This is python.info, produced by makeinfo version 7.1 from python.texi.

     Python 3.13.13, April 07, 2026

     Author name not set

     Copyright © 2001-2026, Python Software Foundation

INFO-DIR-SECTION Miscellaneous
START-INFO-DIR-ENTRY
* python: (python.info). One line description of project
END-INFO-DIR-ENTRY


   Generated by Sphinx 8.2.3.


File: python.info,  Node: Top,  Next: What’s New in Python,  Up: (dir)

Python
******

     Python 3.13.13, April 07, 2026

     Author name not set

     Copyright © 2001-2026, Python Software Foundation

* Menu:

* What’s New in Python::
* The Python Tutorial::
* Python Setup and Usage::
* The Python Language Reference::
* The Python Standard Library::
* Extending and Embedding the Python Interpreter::
* Python/C API Reference Manual::
* Installing Python modules::
* Python HOWTOs::
* Python Frequently Asked Questions::
* Deprecations::
* Glossary::
* About this documentation::
* Dealing with Bugs::
* Copyright::
* History and License::
* Python Module Index::
* Index::

 -- The Detailed Node Listing --

What’s New in Python

* What’s New In Python 3.13: What’s New In Python 3 13.
* What’s New In Python 3.12: What’s New In Python 3 12.
* What’s New In Python 3.11: What’s New In Python 3 11.
* What’s New In Python 3.10: What’s New In Python 3 10.
* What’s New In Python 3.9: What’s New In Python 3 9.
* What’s New In Python 3.8: What’s New In Python 3 8.
* What’s New In Python 3.7: What’s New In Python 3 7.
* What’s New In Python 3.6: What’s New In Python 3 6.
* What’s New In Python 3.5: What’s New In Python 3 5.
* What’s New In Python 3.4: What’s New In Python 3 4.
* What’s New In Python 3.3: What’s New In Python 3 3.
* What’s New In Python 3.2: What’s New In Python 3 2.
* What’s New In Python 3.1: What’s New In Python 3 1.
* What’s New In Python 3.0: What’s New In Python 3 0.
* What’s New in Python 2.7: What’s New in Python 2 7.
* What’s New in Python 2.6: What’s New in Python 2 6.
* What’s New in Python 2.5: What’s New in Python 2 5.
* What’s New in Python 2.4: What’s New in Python 2 4.
* What’s New in Python 2.3: What’s New in Python 2 3.
* What’s New in Python 2.2: What’s New in Python 2 2.
* What’s New in Python 2.1: What’s New in Python 2 1.
* What’s New in Python 2.0: What’s New in Python 2 0.
* Changelog::

What’s New In Python 3.13

* Summary – Release Highlights::
* New Features::
* Other Language Changes::
* New Modules::
* Improved Modules::
* Optimizations::
* Removed Modules And APIs::
* New Deprecations::
* CPython Bytecode Changes::
* C API Changes::
* Build Changes::
* Porting to Python 3.13: Porting to Python 3 13.
* Regression Test Changes::
* Notable changes in 3.13.1: Notable changes in 3 13 1.
* Notable changes in 3.13.4: Notable changes in 3 13 4.

New Features

* A better interactive interpreter::
* Improved error messages::
* Free-threaded CPython::
* An experimental just-in-time (JIT) compiler: An experimental just-in-time JIT compiler.
* Defined mutation semantics for locals(): Defined mutation semantics for locals.
* Support for mobile platforms::

Improved Modules

* argparse::
* array::
* ast::
* asyncio::
* base64::
* compileall::
* concurrent.futures: concurrent futures.
* configparser::
* copy::
* ctypes::
* dbm::
* dis::
* doctest::
* email::
* enum::
* fractions::
* glob::
* importlib::
* io::
* ipaddress::
* itertools::
* marshal::
* math::
* mimetypes::
* mmap::
* multiprocessing::
* os::
* os.path: os path.
* pathlib::
* pdb::
* queue::
* random::
* re::
* shutil::
* site::
* sqlite3::
* ssl::
* statistics::
* subprocess::
* sys::
* tempfile::
* time::
* tkinter::
* traceback::
* types::
* typing::
* unicodedata::
* venv::
* warnings::
* xml::
* zipimport::

Removed Modules And APIs

* PEP 594; Remove “dead batteries” from the standard library: PEP 594 Remove “dead batteries” from the standard library.
* 2to3::
* builtins::
* configparser: configparser<2>.
* importlib.metadata: importlib metadata.
* locale::
* opcode::
* optparse::
* pathlib: pathlib<2>.
* re: re<2>.
* tkinter.tix: tkinter tix.
* turtle::
* typing: typing<2>.
* unittest::
* urllib::
* webbrowser::

New Deprecations

* Pending Removal in Python 3.14: Pending Removal in Python 3 14.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15.
* Pending removal in Python 3.16: Pending removal in Python 3 16.
* Pending removal in Python 3.17: Pending removal in Python 3 17.
* Pending removal in Python 3.18: Pending removal in Python 3 18.
* Pending Removal in Future Versions::

C API Changes

* New Features: New Features<2>.
* Changed C APIs::
* Limited C API Changes::
* Removed C APIs::
* Deprecated C APIs::

Deprecated C APIs

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<2>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<2>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<2>.

Porting to Python 3.13

* Changes in the Python API::
* Changes in the C API::

Notable changes in 3.13.1

* sys: sys<2>.

Notable changes in 3.13.4

* os.path: os path<2>.
* tarfile::

What’s New In Python 3.12

* Summary – Release highlights::
* New Features: New Features<3>.
* New Features Related to Type Hints::
* Other Language Changes: Other Language Changes<2>.
* New Modules: New Modules<2>.
* Improved Modules: Improved Modules<2>.
* Optimizations: Optimizations<2>.
* CPython bytecode changes::
* Demos and Tools::
* Deprecated::
* Removed::
* Porting to Python 3.12: Porting to Python 3 12.
* Build Changes: Build Changes<2>.
* C API Changes: C API Changes<2>.

New Features

* PEP 695; Type Parameter Syntax: PEP 695 Type Parameter Syntax.
* PEP 701; Syntactic formalization of f-strings: PEP 701 Syntactic formalization of f-strings.
* PEP 684; A Per-Interpreter GIL: PEP 684 A Per-Interpreter GIL.
* PEP 669; Low impact monitoring for CPython: PEP 669 Low impact monitoring for CPython.
* PEP 688; Making the buffer protocol accessible in Python: PEP 688 Making the buffer protocol accessible in Python.
* PEP 709; Comprehension inlining: PEP 709 Comprehension inlining.
* Improved Error Messages::

New Features Related to Type Hints

* PEP 692; Using TypedDict for more precise **kwargs typing: PEP 692 Using TypedDict for more precise **kwargs typing.
* PEP 698; Override Decorator for Static Typing: PEP 698 Override Decorator for Static Typing.

Improved Modules

* array: array<2>.
* asyncio: asyncio<2>.
* calendar::
* csv::
* dis: dis<2>.
* fractions: fractions<2>.
* importlib.resources: importlib resources.
* inspect::
* itertools: itertools<2>.
* math: math<2>.
* os: os<2>.
* os.path: os path<3>.
* pathlib: pathlib<3>.
* platform::
* pdb: pdb<2>.
* random: random<2>.
* shutil: shutil<2>.
* sqlite3: sqlite3<2>.
* statistics: statistics<2>.
* sys: sys<3>.
* tempfile: tempfile<2>.
* threading::
* tkinter: tkinter<2>.
* tokenize::
* types: types<2>.
* typing: typing<3>.
* unicodedata: unicodedata<2>.
* unittest: unittest<2>.
* uuid::

Deprecated

* Pending Removal in Python 3.13: Pending Removal in Python 3 13.
* Pending Removal in Python 3.14: Pending Removal in Python 3 14<3>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<3>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<3>.
* Pending removal in Python 3.17: Pending removal in Python 3 17<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<3>.

Removed

* asynchat and asyncore::
* configparser: configparser<3>.
* distutils::
* ensurepip::
* enum: enum<2>.
* ftplib::
* gzip::
* hashlib::
* importlib: importlib<2>.
* imp::
* io: io<2>.
* locale: locale<2>.
* smtpd::
* sqlite3: sqlite3<3>.
* ssl: ssl<2>.
* unittest: unittest<3>.
* webbrowser: webbrowser<2>.
* xml.etree.ElementTree: xml etree ElementTree.
* zipimport: zipimport<2>.
* Others::

Porting to Python 3.12

* Changes in the Python API: Changes in the Python API<2>.

C API Changes

* New Features: New Features<4>.
* Porting to Python 3.12: Porting to Python 3 12<2>.
* Deprecated: Deprecated<2>.
* Removed: Removed<2>.

Deprecated

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<4>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<4>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<4>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<4>.

What’s New In Python 3.11

* Summary – Release highlights: Summary – Release highlights<2>.
* New Features: New Features<5>.
* New Features Related to Type Hints: New Features Related to Type Hints<2>.
* Other Language Changes: Other Language Changes<3>.
* Other CPython Implementation Changes::
* New Modules: New Modules<3>.
* Improved Modules: Improved Modules<3>.
* Optimizations: Optimizations<3>.
* Faster CPython::
* CPython bytecode changes: CPython bytecode changes<2>.
* Deprecated: Deprecated<3>.
* Pending Removal in Python 3.12: Pending Removal in Python 3 12.
* Removed: Removed<3>.
* Porting to Python 3.11: Porting to Python 3 11.
* Build Changes: Build Changes<3>.
* C API Changes: C API Changes<3>.
* Notable changes in 3.11.4: Notable changes in 3 11 4.
* Notable changes in 3.11.5: Notable changes in 3 11 5.

New Features

* PEP 657; Fine-grained error locations in tracebacks: PEP 657 Fine-grained error locations in tracebacks.
* PEP 654; Exception Groups and except*: PEP 654 Exception Groups and except*.
* PEP 678; Exceptions can be enriched with notes: PEP 678 Exceptions can be enriched with notes.
* Windows py.exe launcher improvements: Windows py exe launcher improvements.

New Features Related to Type Hints

* PEP 646; Variadic generics: PEP 646 Variadic generics.
* PEP 655; Marking individual TypedDict items as required or not-required: PEP 655 Marking individual TypedDict items as required or not-required.
* PEP 673; Self type: PEP 673 Self type.
* PEP 675; Arbitrary literal string type: PEP 675 Arbitrary literal string type.
* PEP 681; Data class transforms: PEP 681 Data class transforms.
* PEP 563 may not be the future::

Improved Modules

* asyncio: asyncio<3>.
* contextlib::
* dataclasses::
* datetime::
* enum: enum<3>.
* fcntl::
* fractions: fractions<3>.
* functools::
* gzip: gzip<2>.
* hashlib: hashlib<2>.
* IDLE and idlelib::
* inspect: inspect<2>.
* locale: locale<3>.
* logging::
* math: math<3>.
* operator::
* os: os<3>.
* pathlib: pathlib<4>.
* re: re<3>.
* shutil: shutil<3>.
* socket::
* sqlite3: sqlite3<4>.
* string::
* sys: sys<4>.
* sysconfig::
* tempfile: tempfile<3>.
* threading: threading<2>.
* time: time<2>.
* tkinter: tkinter<3>.
* traceback: traceback<2>.
* typing: typing<4>.
* unicodedata: unicodedata<3>.
* unittest: unittest<4>.
* venv: venv<2>.
* warnings: warnings<2>.
* zipfile::

Faster CPython

* Faster Startup::
* Faster Runtime::
* Misc::
* FAQ::
* About::

Faster Startup

* Frozen imports / Static code objects::

Faster Runtime

* Cheaper, lazy Python frames: Cheaper lazy Python frames.
* Inlined Python function calls::
* PEP 659; Specializing Adaptive Interpreter: PEP 659 Specializing Adaptive Interpreter.

FAQ

* How should I write my code to utilize these speedups?::
* Will CPython 3.11 use more memory?: Will CPython 3 11 use more memory?.
* I don’t see any speedups in my workload. Why?: I don’t see any speedups in my workload Why?.
* Is there a JIT compiler?::

CPython bytecode changes

* New opcodes::
* Replaced opcodes::
* Changed/removed opcodes::

Deprecated

* Language/Builtins::
* Modules::
* Standard Library::

C API Changes

* New Features: New Features<6>.
* Porting to Python 3.11: Porting to Python 3 11<2>.
* Deprecated: Deprecated<4>.
* Pending Removal in Python 3.12: Pending Removal in Python 3 12<2>.
* Removed: Removed<4>.

Notable changes in 3.11.4

* tarfile: tarfile<2>.

Notable changes in 3.11.5

* OpenSSL::

What’s New In Python 3.10

* Summary – Release highlights: Summary – Release highlights<3>.
* New Features: New Features<7>.
* New Features Related to Type Hints: New Features Related to Type Hints<3>.
* Other Language Changes: Other Language Changes<4>.
* New Modules: New Modules<4>.
* Improved Modules: Improved Modules<4>.
* Optimizations: Optimizations<4>.
* Deprecated: Deprecated<5>.
* Removed: Removed<5>.
* Porting to Python 3.10: Porting to Python 3 10.
* CPython bytecode changes: CPython bytecode changes<3>.
* Build Changes: Build Changes<4>.
* C API Changes: C API Changes<4>.
* Notable security feature in 3.10.7: Notable security feature in 3 10 7.
* Notable security feature in 3.10.8: Notable security feature in 3 10 8.
* Notable changes in 3.10.12: Notable changes in 3 10 12.

New Features

* Parenthesized context managers::
* Better error messages::
* PEP 626; Precise line numbers for debugging and other tools: PEP 626 Precise line numbers for debugging and other tools.
* PEP 634; Structural Pattern Matching: PEP 634 Structural Pattern Matching.
* Optional EncodingWarning and encoding="locale" option::

Better error messages

* SyntaxErrors::
* IndentationErrors::
* AttributeErrors::
* NameErrors::

PEP 634: Structural Pattern Matching

* Syntax and operations::
* Declarative approach::
* Simple pattern; match to a literal: Simple pattern match to a literal.
* Patterns with a literal and variable::
* Patterns and classes::
* Nested patterns::
* Complex patterns and the wildcard::
* Guard::
* Other Key Features::

Simple pattern: match to a literal

* Behavior without the wildcard::

Patterns and classes

* Patterns with positional parameters::

New Features Related to Type Hints

* PEP 604; New Type Union Operator: PEP 604 New Type Union Operator.
* PEP 612; Parameter Specification Variables: PEP 612 Parameter Specification Variables.
* PEP 613; TypeAlias: PEP 613 TypeAlias.
* PEP 647; User-Defined Type Guards: PEP 647 User-Defined Type Guards.

Improved Modules

* asyncio: asyncio<4>.
* argparse: argparse<2>.
* array: array<3>.
* asynchat, asyncore, smtpd: asynchat asyncore smtpd.
* base64: base64<2>.
* bdb::
* bisect::
* codecs::
* collections.abc: collections abc.
* contextlib: contextlib<2>.
* curses::
* dataclasses: dataclasses<2>.
* distutils: distutils<2>.
* doctest: doctest<2>.
* encodings::
* enum: enum<4>.
* fileinput::
* faulthandler::
* gc::
* glob: glob<2>.
* hashlib: hashlib<3>.
* hmac::
* IDLE and idlelib: IDLE and idlelib<2>.
* importlib.metadata: importlib metadata<2>.
* inspect: inspect<3>.
* itertools: itertools<3>.
* linecache::
* os: os<4>.
* os.path: os path<4>.
* pathlib: pathlib<5>.
* platform: platform<2>.
* pprint::
* py_compile::
* pyclbr::
* shelve::
* statistics: statistics<3>.
* site: site<2>.
* socket: socket<2>.
* ssl: ssl<3>.
* sqlite3: sqlite3<5>.
* sys: sys<5>.
* _thread::
* threading: threading<3>.
* traceback: traceback<3>.
* types: types<3>.
* typing: typing<5>.
* unittest: unittest<5>.
* urllib.parse: urllib parse.
* xml: xml<2>.
* zipimport: zipimport<3>.

dataclasses

* __slots__::
* Keyword-only fields::

Porting to Python 3.10

* Changes in the Python syntax::
* Changes in the Python API: Changes in the Python API<3>.
* Changes in the C API: Changes in the C API<2>.

C API Changes

* PEP 652; Maintaining the Stable ABI: PEP 652 Maintaining the Stable ABI.
* New Features: New Features<8>.
* Porting to Python 3.10: Porting to Python 3 10<2>.
* Deprecated: Deprecated<6>.
* Removed: Removed<6>.

Notable changes in 3.10.12

* tarfile: tarfile<3>.

What’s New In Python 3.9

* Summary – Release highlights: Summary – Release highlights<4>.
* You should check for DeprecationWarning in your code::
* New Features: New Features<9>.
* Other Language Changes: Other Language Changes<5>.
* New Modules: New Modules<5>.
* Improved Modules: Improved Modules<5>.
* Optimizations: Optimizations<5>.
* Deprecated: Deprecated<7>.
* Removed: Removed<7>.
* Porting to Python 3.9: Porting to Python 3 9.
* Build Changes: Build Changes<5>.
* C API Changes: C API Changes<5>.
* Notable changes in Python 3.9.1: Notable changes in Python 3 9 1.
* Notable changes in Python 3.9.2: Notable changes in Python 3 9 2.
* Notable changes in Python 3.9.3: Notable changes in Python 3 9 3.
* Notable changes in Python 3.9.5: Notable changes in Python 3 9 5.
* Notable security feature in 3.9.14: Notable security feature in 3 9 14.
* Notable changes in 3.9.17: Notable changes in 3 9 17.

New Features

* Dictionary Merge & Update Operators::
* New String Methods to Remove Prefixes and Suffixes::
* Type Hinting Generics in Standard Collections::
* New Parser::

New Modules

* zoneinfo::
* graphlib::

Improved Modules

* ast: ast<2>.
* asyncio: asyncio<5>.
* compileall: compileall<2>.
* concurrent.futures: concurrent futures<2>.
* curses: curses<2>.
* datetime: datetime<2>.
* distutils: distutils<3>.
* fcntl: fcntl<2>.
* ftplib: ftplib<2>.
* gc: gc<2>.
* hashlib: hashlib<4>.
* http::
* IDLE and idlelib: IDLE and idlelib<3>.
* imaplib::
* importlib: importlib<3>.
* inspect: inspect<4>.
* ipaddress: ipaddress<2>.
* math: math<4>.
* multiprocessing: multiprocessing<2>.
* nntplib::
* os: os<5>.
* pathlib: pathlib<6>.
* pdb: pdb<3>.
* poplib::
* pprint: pprint<2>.
* pydoc::
* random: random<3>.
* signal::
* smtplib::
* socket: socket<3>.
* time: time<3>.
* sys: sys<6>.
* tracemalloc::
* typing: typing<6>.
* unicodedata: unicodedata<4>.
* venv: venv<3>.
* xml: xml<3>.

Porting to Python 3.9

* Changes in the Python API: Changes in the Python API<4>.
* Changes in the C API: Changes in the C API<3>.
* CPython bytecode changes: CPython bytecode changes<4>.

C API Changes

* New Features: New Features<10>.
* Porting to Python 3.9: Porting to Python 3 9<2>.
* Removed: Removed<8>.

Notable changes in Python 3.9.1

* typing: typing<7>.
* macOS 11.0 (Big Sur) and Apple Silicon Mac support: macOS 11 0 Big Sur and Apple Silicon Mac support.

Notable changes in Python 3.9.2

* collections.abc: collections abc<2>.
* urllib.parse: urllib parse<2>.

Notable changes in Python 3.9.5

* urllib.parse: urllib parse<3>.

Notable changes in 3.9.17

* tarfile: tarfile<4>.

What’s New In Python 3.8

* Summary – Release highlights: Summary – Release highlights<5>.
* New Features: New Features<11>.
* Other Language Changes: Other Language Changes<6>.
* New Modules: New Modules<6>.
* Improved Modules: Improved Modules<6>.
* Optimizations: Optimizations<6>.
* Build and C API Changes::
* Deprecated: Deprecated<8>.
* API and Feature Removals::
* Porting to Python 3.8: Porting to Python 3 8.
* Notable changes in Python 3.8.1: Notable changes in Python 3 8 1.
* Notable changes in Python 3.8.2: Notable changes in Python 3 8 2.
* Notable changes in Python 3.8.3: Notable changes in Python 3 8 3.
* Notable changes in Python 3.8.8: Notable changes in Python 3 8 8.
* Notable changes in Python 3.8.9: Notable changes in Python 3 8 9.
* Notable changes in Python 3.8.10: Notable changes in Python 3 8 10.
* Notable changes in Python 3.8.10: Notable changes in Python 3 8 10<2>.
* Notable changes in Python 3.8.12: Notable changes in Python 3 8 12.
* Notable security feature in 3.8.14: Notable security feature in 3 8 14.
* Notable changes in 3.8.17: Notable changes in 3 8 17.

New Features

* Assignment expressions::
* Positional-only parameters::
* Parallel filesystem cache for compiled bytecode files::
* Debug build uses the same ABI as release build::
* f-strings support = for self-documenting expressions and debugging::
* PEP 578; Python Runtime Audit Hooks: PEP 578 Python Runtime Audit Hooks.
* PEP 587; Python Initialization Configuration: PEP 587 Python Initialization Configuration.
* PEP 590; Vectorcall; a fast calling protocol for CPython: PEP 590 Vectorcall a fast calling protocol for CPython.
* Pickle protocol 5 with out-of-band data buffers::

Improved Modules

* ast: ast<3>.
* asyncio: asyncio<6>.
* builtins: builtins<2>.
* collections::
* cProfile::
* csv: csv<2>.
* curses: curses<3>.
* ctypes: ctypes<2>.
* datetime: datetime<3>.
* functools: functools<2>.
* gc: gc<3>.
* gettext::
* gzip: gzip<3>.
* IDLE and idlelib: IDLE and idlelib<4>.
* inspect: inspect<5>.
* io: io<3>.
* itertools: itertools<4>.
* json.tool: json tool.
* logging: logging<2>.
* math: math<5>.
* mmap: mmap<2>.
* multiprocessing: multiprocessing<3>.
* os: os<6>.
* os.path: os path<5>.
* pathlib: pathlib<7>.
* pickle::
* plistlib::
* pprint: pprint<3>.
* py_compile: py_compile<2>.
* shlex::
* shutil: shutil<4>.
* socket: socket<4>.
* ssl: ssl<4>.
* statistics: statistics<4>.
* sys: sys<7>.
* tarfile: tarfile<5>.
* threading: threading<4>.
* tokenize: tokenize<2>.
* tkinter: tkinter<4>.
* time: time<4>.
* typing: typing<8>.
* unicodedata: unicodedata<5>.
* unittest: unittest<6>.
* venv: venv<4>.
* weakref::
* xml: xml<4>.
* xmlrpc::

Porting to Python 3.8

* Changes in Python behavior::
* Changes in the Python API: Changes in the Python API<5>.
* Changes in the C API: Changes in the C API<4>.
* CPython bytecode changes: CPython bytecode changes<5>.
* Demos and Tools: Demos and Tools<2>.

Notable changes in Python 3.8.10

* macOS 11.0 (Big Sur) and Apple Silicon Mac support: macOS 11 0 Big Sur and Apple Silicon Mac support<2>.

Notable changes in Python 3.8.10

* urllib.parse: urllib parse<4>.

Notable changes in Python 3.8.12

* Changes in the Python API: Changes in the Python API<6>.

Notable changes in 3.8.17

* tarfile: tarfile<6>.

What’s New In Python 3.7

* Summary – Release Highlights: Summary – Release Highlights<2>.
* New Features: New Features<12>.
* Other Language Changes: Other Language Changes<7>.
* New Modules: New Modules<7>.
* Improved Modules: Improved Modules<7>.
* C API Changes: C API Changes<6>.
* Build Changes: Build Changes<6>.
* Optimizations: Optimizations<7>.
* Other CPython Implementation Changes: Other CPython Implementation Changes<2>.
* Deprecated Python Behavior::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods.
* Deprecated functions and types of the C API::
* Platform Support Removals::
* API and Feature Removals: API and Feature Removals<2>.
* Module Removals::
* Windows-only Changes::
* Porting to Python 3.7: Porting to Python 3 7.
* Notable changes in Python 3.7.1: Notable changes in Python 3 7 1.
* Notable changes in Python 3.7.2: Notable changes in Python 3 7 2.
* Notable changes in Python 3.7.6: Notable changes in Python 3 7 6.
* Notable changes in Python 3.7.10: Notable changes in Python 3 7 10.
* Notable changes in Python 3.7.11: Notable changes in Python 3 7 11.
* Notable security feature in 3.7.14: Notable security feature in 3 7 14.

New Features

* PEP 563; Postponed Evaluation of Annotations: PEP 563 Postponed Evaluation of Annotations.
* PEP 538; Legacy C Locale Coercion: PEP 538 Legacy C Locale Coercion.
* PEP 540; Forced UTF-8 Runtime Mode: PEP 540 Forced UTF-8 Runtime Mode.
* PEP 553; Built-in breakpoint(): PEP 553 Built-in breakpoint.
* PEP 539; New C API for Thread-Local Storage: PEP 539 New C API for Thread-Local Storage.
* PEP 562; Customization of Access to Module Attributes: PEP 562 Customization of Access to Module Attributes.
* PEP 564; New Time Functions With Nanosecond Resolution: PEP 564 New Time Functions With Nanosecond Resolution.
* PEP 565; Show DeprecationWarning in __main__: PEP 565 Show DeprecationWarning in __main__.
* PEP 560; Core Support for typing module and Generic Types: PEP 560 Core Support for typing module and Generic Types.
* PEP 552; Hash-based .pyc Files: PEP 552 Hash-based pyc Files.
* PEP 545; Python Documentation Translations: PEP 545 Python Documentation Translations.
* Python Development Mode (-X dev): Python Development Mode -X dev.

New Modules

* contextvars::
* dataclasses: dataclasses<3>.
* importlib.resources: importlib resources<2>.

Improved Modules

* argparse: argparse<3>.
* asyncio: asyncio<7>.
* binascii::
* calendar: calendar<2>.
* collections: collections<2>.
* compileall: compileall<3>.
* concurrent.futures: concurrent futures<3>.
* contextlib: contextlib<3>.
* cProfile: cProfile<2>.
* crypt::
* datetime: datetime<4>.
* dbm: dbm<2>.
* decimal::
* dis: dis<3>.
* distutils: distutils<4>.
* enum: enum<5>.
* functools: functools<3>.
* gc: gc<4>.
* hmac: hmac<2>.
* http.client: http client.
* http.server: http server.
* idlelib and IDLE::
* importlib: importlib<4>.
* io: io<4>.
* ipaddress: ipaddress<3>.
* itertools: itertools<5>.
* locale: locale<4>.
* logging: logging<3>.
* math: math<6>.
* mimetypes: mimetypes<2>.
* msilib::
* multiprocessing: multiprocessing<4>.
* os: os<7>.
* pathlib: pathlib<8>.
* pdb: pdb<4>.
* py_compile: py_compile<3>.
* pydoc: pydoc<2>.
* queue: queue<2>.
* re: re<4>.
* signal: signal<2>.
* socket: socket<5>.
* socketserver::
* sqlite3: sqlite3<6>.
* ssl: ssl<5>.
* string: string<2>.
* subprocess: subprocess<2>.
* sys: sys<8>.
* time: time<5>.
* tkinter: tkinter<5>.
* tracemalloc: tracemalloc<2>.
* types: types<4>.
* unicodedata: unicodedata<6>.
* unittest: unittest<7>.
* unittest.mock: unittest mock.
* urllib.parse: urllib parse<5>.
* uu::
* uuid: uuid<2>.
* warnings: warnings<3>.
* xml: xml<5>.
* xml.etree: xml etree.
* xmlrpc.server: xmlrpc server.
* zipapp::
* zipfile: zipfile<2>.

Deprecated Python modules, functions and methods

* aifc::
* asyncio: asyncio<8>.
* collections: collections<3>.
* dbm: dbm<3>.
* enum: enum<6>.
* gettext: gettext<2>.
* importlib: importlib<5>.
* locale: locale<5>.
* macpath::
* threading: threading<5>.
* socket: socket<6>.
* ssl: ssl<6>.
* sunau::
* sys: sys<9>.
* wave::

Porting to Python 3.7

* Changes in Python Behavior::
* Changes in the Python API: Changes in the Python API<7>.
* Changes in the C API: Changes in the C API<5>.
* CPython bytecode changes: CPython bytecode changes<6>.
* Windows-only Changes: Windows-only Changes<2>.
* Other CPython implementation changes::

What’s New In Python 3.6

* Summary – Release highlights: Summary – Release highlights<6>.
* New Features: New Features<13>.
* Other Language Changes: Other Language Changes<8>.
* New Modules: New Modules<8>.
* Improved Modules: Improved Modules<8>.
* Optimizations: Optimizations<8>.
* Build and C API Changes: Build and C API Changes<2>.
* Other Improvements::
* Deprecated: Deprecated<9>.
* Removed: Removed<9>.
* Porting to Python 3.6: Porting to Python 3 6.
* Notable changes in Python 3.6.2: Notable changes in Python 3 6 2.
* Notable changes in Python 3.6.4: Notable changes in Python 3 6 4.
* Notable changes in Python 3.6.5: Notable changes in Python 3 6 5.
* Notable changes in Python 3.6.7: Notable changes in Python 3 6 7.
* Notable changes in Python 3.6.10: Notable changes in Python 3 6 10.
* Notable changes in Python 3.6.13: Notable changes in Python 3 6 13.
* Notable changes in Python 3.6.14: Notable changes in Python 3 6 14.

New Features

* PEP 498; Formatted string literals: PEP 498 Formatted string literals.
* PEP 526; Syntax for variable annotations: PEP 526 Syntax for variable annotations.
* PEP 515; Underscores in Numeric Literals: PEP 515 Underscores in Numeric Literals.
* PEP 525; Asynchronous Generators: PEP 525 Asynchronous Generators.
* PEP 530; Asynchronous Comprehensions: PEP 530 Asynchronous Comprehensions.
* PEP 487; Simpler customization of class creation: PEP 487 Simpler customization of class creation.
* PEP 487; Descriptor Protocol Enhancements: PEP 487 Descriptor Protocol Enhancements.
* PEP 519; Adding a file system path protocol: PEP 519 Adding a file system path protocol.
* PEP 495; Local Time Disambiguation: PEP 495 Local Time Disambiguation.
* PEP 529; Change Windows filesystem encoding to UTF-8: PEP 529 Change Windows filesystem encoding to UTF-8.
* PEP 528; Change Windows console encoding to UTF-8: PEP 528 Change Windows console encoding to UTF-8.
* PEP 520; Preserving Class Attribute Definition Order: PEP 520 Preserving Class Attribute Definition Order.
* PEP 468; Preserving Keyword Argument Order: PEP 468 Preserving Keyword Argument Order.
* New dict implementation::
* PEP 523; Adding a frame evaluation API to CPython: PEP 523 Adding a frame evaluation API to CPython.
* PYTHONMALLOC environment variable::
* DTrace and SystemTap probing support::

New Modules

* secrets::

Improved Modules

* array: array<4>.
* ast: ast<4>.
* asyncio: asyncio<9>.
* binascii: binascii<2>.
* cmath::
* collections: collections<4>.
* concurrent.futures: concurrent futures<4>.
* contextlib: contextlib<4>.
* datetime: datetime<5>.
* decimal: decimal<2>.
* distutils: distutils<5>.
* email: email<2>.
* encodings: encodings<2>.
* enum: enum<7>.
* faulthandler: faulthandler<2>.
* fileinput: fileinput<2>.
* hashlib: hashlib<5>.
* http.client: http client<2>.
* idlelib and IDLE: idlelib and IDLE<2>.
* importlib: importlib<6>.
* inspect: inspect<6>.
* json::
* logging: logging<4>.
* math: math<7>.
* multiprocessing: multiprocessing<5>.
* os: os<8>.
* pathlib: pathlib<9>.
* pdb: pdb<5>.
* pickle: pickle<2>.
* pickletools::
* pydoc: pydoc<3>.
* random: random<4>.
* re: re<5>.
* readline::
* rlcompleter::
* shlex: shlex<2>.
* site: site<3>.
* sqlite3: sqlite3<7>.
* socket: socket<7>.
* socketserver: socketserver<2>.
* ssl: ssl<7>.
* statistics: statistics<5>.
* struct::
* subprocess: subprocess<3>.
* sys: sys<10>.
* telnetlib::
* time: time<6>.
* timeit::
* tkinter: tkinter<6>.
* traceback: traceback<4>.
* tracemalloc: tracemalloc<3>.
* typing: typing<9>.
* unicodedata: unicodedata<7>.
* unittest.mock: unittest mock<2>.
* urllib.request: urllib request.
* urllib.robotparser: urllib robotparser.
* venv: venv<5>.
* warnings: warnings<4>.
* winreg::
* winsound::
* xmlrpc.client: xmlrpc client.
* zipfile: zipfile<3>.
* zlib::

Deprecated

* New Keywords::
* Deprecated Python behavior::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<2>.
* xml: xml<6>.
* Deprecated functions and types of the C API: Deprecated functions and types of the C API<2>.
* Deprecated Build Options::

Deprecated Python modules, functions and methods

* asynchat::
* asyncore::
* dbm: dbm<4>.
* distutils: distutils<6>.
* grp::
* importlib: importlib<7>.
* os: os<9>.
* re: re<6>.
* ssl: ssl<8>.
* tkinter: tkinter<7>.
* venv: venv<6>.

Removed

* API and Feature Removals: API and Feature Removals<3>.

Porting to Python 3.6

* Changes in ‘python’ Command Behavior::
* Changes in the Python API: Changes in the Python API<8>.
* Changes in the C API: Changes in the C API<6>.
* CPython bytecode changes: CPython bytecode changes<7>.

Notable changes in Python 3.6.2

* New make regen-all build target::
* Removal of make touch build target::

What’s New In Python 3.5

* Summary – Release highlights: Summary – Release highlights<7>.
* New Features: New Features<14>.
* Other Language Changes: Other Language Changes<9>.
* New Modules: New Modules<9>.
* Improved Modules: Improved Modules<9>.
* Other module-level changes::
* Optimizations: Optimizations<9>.
* Build and C API Changes: Build and C API Changes<3>.
* Deprecated: Deprecated<10>.
* Removed: Removed<10>.
* Porting to Python 3.5: Porting to Python 3 5.
* Notable changes in Python 3.5.4: Notable changes in Python 3 5 4.

New Features

* PEP 492 - Coroutines with async and await syntax::
* PEP 465 - A dedicated infix operator for matrix multiplication::
* PEP 448 - Additional Unpacking Generalizations::
* PEP 461 - percent formatting support for bytes and bytearray::
* PEP 484 - Type Hints::
* PEP 471 - os.scandir() function – a better and faster directory iterator: PEP 471 - os scandir function – a better and faster directory iterator.
* PEP 475; Retry system calls failing with EINTR: PEP 475 Retry system calls failing with EINTR.
* PEP 479; Change StopIteration handling inside generators: PEP 479 Change StopIteration handling inside generators.
* PEP 485; A function for testing approximate equality: PEP 485 A function for testing approximate equality.
* PEP 486; Make the Python Launcher aware of virtual environments: PEP 486 Make the Python Launcher aware of virtual environments.
* PEP 488; Elimination of PYO files: PEP 488 Elimination of PYO files.
* PEP 489; Multi-phase extension module initialization: PEP 489 Multi-phase extension module initialization.

New Modules

* typing: typing<10>.
* zipapp: zipapp<2>.

Improved Modules

* argparse: argparse<4>.
* asyncio: asyncio<10>.
* bz2::
* cgi::
* cmath: cmath<2>.
* code::
* collections: collections<5>.
* collections.abc: collections abc<3>.
* compileall: compileall<4>.
* concurrent.futures: concurrent futures<5>.
* configparser: configparser<4>.
* contextlib: contextlib<5>.
* csv: csv<3>.
* curses: curses<4>.
* dbm: dbm<5>.
* difflib::
* distutils: distutils<7>.
* doctest: doctest<3>.
* email: email<3>.
* enum: enum<8>.
* faulthandler: faulthandler<3>.
* functools: functools<4>.
* glob: glob<3>.
* gzip: gzip<4>.
* heapq::
* http: http<2>.
* http.client: http client<3>.
* idlelib and IDLE: idlelib and IDLE<3>.
* imaplib: imaplib<2>.
* imghdr::
* importlib: importlib<8>.
* inspect: inspect<7>.
* io: io<5>.
* ipaddress: ipaddress<4>.
* json: json<2>.
* linecache: linecache<2>.
* locale: locale<6>.
* logging: logging<5>.
* lzma::
* math: math<8>.
* multiprocessing: multiprocessing<6>.
* operator: operator<2>.
* os: os<10>.
* pathlib: pathlib<10>.
* pickle: pickle<3>.
* poplib: poplib<2>.
* re: re<7>.
* readline: readline<2>.
* selectors::
* shutil: shutil<5>.
* signal: signal<3>.
* smtpd: smtpd<2>.
* smtplib: smtplib<2>.
* sndhdr::
* socket: socket<8>.
* ssl: ssl<9>.
* sqlite3: sqlite3<8>.
* subprocess: subprocess<4>.
* sys: sys<11>.
* sysconfig: sysconfig<2>.
* tarfile: tarfile<7>.
* threading: threading<6>.
* time: time<7>.
* timeit: timeit<2>.
* tkinter: tkinter<8>.
* traceback: traceback<5>.
* types: types<5>.
* unicodedata: unicodedata<8>.
* unittest: unittest<8>.
* unittest.mock: unittest mock<3>.
* urllib: urllib<2>.
* wsgiref::
* xmlrpc: xmlrpc<2>.
* xml.sax: xml sax.
* zipfile: zipfile<4>.

ssl

* Memory BIO Support::
* Application-Layer Protocol Negotiation Support::
* Other Changes::

Deprecated

* New Keywords: New Keywords<2>.
* Deprecated Python Behavior: Deprecated Python Behavior<2>.
* Unsupported Operating Systems::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<3>.

Removed

* API and Feature Removals: API and Feature Removals<4>.

Porting to Python 3.5

* Changes in Python behavior: Changes in Python behavior<2>.
* Changes in the Python API: Changes in the Python API<9>.
* Changes in the C API: Changes in the C API<7>.

Notable changes in Python 3.5.4

* New make regen-all build target: New make regen-all build target<2>.
* Removal of make touch build target: Removal of make touch build target<2>.

What’s New In Python 3.4

* Summary – Release Highlights: Summary – Release Highlights<3>.
* New Features: New Features<15>.
* New Modules: New Modules<10>.
* Improved Modules: Improved Modules<10>.
* CPython Implementation Changes::
* Deprecated: Deprecated<11>.
* Removed: Removed<11>.
* Porting to Python 3.4: Porting to Python 3 4.
* Changed in 3.4.3: Changed in 3 4 3.

New Features

* PEP 453; Explicit Bootstrapping of PIP in Python Installations: PEP 453 Explicit Bootstrapping of PIP in Python Installations.
* PEP 446; Newly Created File Descriptors Are Non-Inheritable: PEP 446 Newly Created File Descriptors Are Non-Inheritable.
* Improvements to Codec Handling::
* PEP 451; A ModuleSpec Type for the Import System: PEP 451 A ModuleSpec Type for the Import System.
* Other Language Changes: Other Language Changes<10>.

PEP 453: Explicit Bootstrapping of PIP in Python Installations

* Bootstrapping pip By Default::
* Documentation Changes::

New Modules

* asyncio: asyncio<11>.
* ensurepip: ensurepip<2>.
* enum: enum<9>.
* pathlib: pathlib<11>.
* selectors: selectors<2>.
* statistics: statistics<6>.
* tracemalloc: tracemalloc<4>.

Improved Modules

* abc::
* aifc: aifc<2>.
* argparse: argparse<5>.
* audioop::
* base64: base64<3>.
* collections: collections<6>.
* colorsys::
* contextlib: contextlib<6>.
* dbm: dbm<6>.
* dis: dis<4>.
* doctest: doctest<4>.
* email: email<4>.
* filecmp::
* functools: functools<5>.
* gc: gc<5>.
* glob: glob<4>.
* hashlib: hashlib<6>.
* hmac: hmac<3>.
* html::
* http: http<3>.
* idlelib and IDLE: idlelib and IDLE<4>.
* importlib: importlib<9>.
* inspect: inspect<8>.
* ipaddress: ipaddress<5>.
* logging: logging<6>.
* marshal: marshal<2>.
* mmap: mmap<3>.
* multiprocessing: multiprocessing<7>.
* operator: operator<3>.
* os: os<11>.
* pdb: pdb<6>.
* pickle: pickle<4>.
* plistlib: plistlib<2>.
* poplib: poplib<3>.
* pprint: pprint<4>.
* pty::
* pydoc: pydoc<4>.
* re: re<8>.
* resource::
* select::
* shelve: shelve<2>.
* shutil: shutil<6>.
* smtpd: smtpd<3>.
* smtplib: smtplib<3>.
* socket: socket<9>.
* sqlite3: sqlite3<9>.
* ssl: ssl<10>.
* stat::
* struct: struct<2>.
* subprocess: subprocess<5>.
* sunau: sunau<2>.
* sys: sys<12>.
* tarfile: tarfile<8>.
* textwrap::
* threading: threading<7>.
* traceback: traceback<6>.
* types: types<6>.
* urllib: urllib<3>.
* unittest: unittest<9>.
* venv: venv<7>.
* wave: wave<2>.
* weakref: weakref<2>.
* xml.etree: xml etree<2>.
* zipfile: zipfile<5>.

CPython Implementation Changes

* PEP 445; Customization of CPython Memory Allocators: PEP 445 Customization of CPython Memory Allocators.
* PEP 442; Safe Object Finalization: PEP 442 Safe Object Finalization.
* PEP 456; Secure and Interchangeable Hash Algorithm: PEP 456 Secure and Interchangeable Hash Algorithm.
* PEP 436; Argument Clinic: PEP 436 Argument Clinic.
* Other Build and C API Changes::
* Other Improvements: Other Improvements<2>.
* Significant Optimizations::

Deprecated

* Deprecations in the Python API::
* Deprecated Features::

Removed

* Operating Systems No Longer Supported::
* API and Feature Removals: API and Feature Removals<5>.
* Code Cleanups::

Porting to Python 3.4

* Changes in ‘python’ Command Behavior: Changes in ‘python’ Command Behavior<2>.
* Changes in the Python API: Changes in the Python API<10>.
* Changes in the C API: Changes in the C API<8>.

Changed in 3.4.3

* PEP 476; Enabling certificate verification by default for stdlib http clients: PEP 476 Enabling certificate verification by default for stdlib http clients.

What’s New In Python 3.3

* Summary – Release highlights: Summary – Release highlights<8>.
* PEP 405; Virtual Environments: PEP 405 Virtual Environments.
* PEP 420; Implicit Namespace Packages: PEP 420 Implicit Namespace Packages.
* PEP 3118; New memoryview implementation and buffer protocol documentation: PEP 3118 New memoryview implementation and buffer protocol documentation.
* PEP 393; Flexible String Representation: PEP 393 Flexible String Representation.
* PEP 397; Python Launcher for Windows: PEP 397 Python Launcher for Windows.
* PEP 3151; Reworking the OS and IO exception hierarchy: PEP 3151 Reworking the OS and IO exception hierarchy.
* PEP 380; Syntax for Delegating to a Subgenerator: PEP 380 Syntax for Delegating to a Subgenerator.
* PEP 409; Suppressing exception context: PEP 409 Suppressing exception context.
* PEP 414; Explicit Unicode literals: PEP 414 Explicit Unicode literals.
* PEP 3155; Qualified name for classes and functions: PEP 3155 Qualified name for classes and functions.
* PEP 412; Key-Sharing Dictionary: PEP 412 Key-Sharing Dictionary.
* PEP 362; Function Signature Object: PEP 362 Function Signature Object.
* PEP 421; Adding sys.implementation: PEP 421 Adding sys implementation.
* Using importlib as the Implementation of Import::
* Other Language Changes: Other Language Changes<11>.
* A Finer-Grained Import Lock::
* Builtin functions and types::
* New Modules: New Modules<11>.
* Improved Modules: Improved Modules<11>.
* Optimizations: Optimizations<10>.
* Build and C API Changes: Build and C API Changes<4>.
* Deprecated: Deprecated<12>.
* Porting to Python 3.3: Porting to Python 3 3.

PEP 3118: New memoryview implementation and buffer protocol documentation

* Features::
* API changes::

PEP 393: Flexible String Representation

* Functionality::
* Performance and resource usage::

PEP 421: Adding sys.implementation

* SimpleNamespace::

Using importlib as the Implementation of Import

* New APIs::
* Visible Changes::

New Modules

* faulthandler: faulthandler<4>.
* ipaddress: ipaddress<6>.
* lzma: lzma<2>.

Improved Modules

* abc: abc<2>.
* array: array<5>.
* base64: base64<4>.
* binascii: binascii<3>.
* bz2: bz2<2>.
* codecs: codecs<2>.
* collections: collections<7>.
* contextlib: contextlib<7>.
* crypt: crypt<2>.
* curses: curses<5>.
* datetime: datetime<6>.
* decimal: decimal<3>.
* email: email<5>.
* ftplib: ftplib<3>.
* functools: functools<6>.
* gc: gc<6>.
* hmac: hmac<4>.
* http: http<4>.
* html: html<2>.
* imaplib: imaplib<3>.
* inspect: inspect<9>.
* io: io<6>.
* itertools: itertools<6>.
* logging: logging<7>.
* math: math<9>.
* mmap: mmap<4>.
* multiprocessing: multiprocessing<8>.
* nntplib: nntplib<2>.
* os: os<12>.
* pdb: pdb<7>.
* pickle: pickle<5>.
* pydoc: pydoc<5>.
* re: re<9>.
* sched::
* select: select<2>.
* shlex: shlex<3>.
* shutil: shutil<7>.
* signal: signal<4>.
* smtpd: smtpd<4>.
* smtplib: smtplib<4>.
* socket: socket<10>.
* socketserver: socketserver<3>.
* sqlite3: sqlite3<10>.
* ssl: ssl<11>.
* stat: stat<2>.
* struct: struct<3>.
* subprocess: subprocess<6>.
* sys: sys<13>.
* tarfile: tarfile<9>.
* tempfile: tempfile<4>.
* textwrap: textwrap<2>.
* threading: threading<8>.
* time: time<8>.
* types: types<7>.
* unittest: unittest<10>.
* urllib: urllib<4>.
* webbrowser: webbrowser<3>.
* xml.etree.ElementTree: xml etree ElementTree<2>.
* zlib: zlib<2>.

decimal

* Features: Features<2>.
* API changes: API changes<2>.

email

* Policy Framework::
* Provisional Policy with New Header API::
* Other API Changes::

Deprecated

* Unsupported Operating Systems: Unsupported Operating Systems<2>.
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<4>.
* Deprecated functions and types of the C API: Deprecated functions and types of the C API<3>.
* Deprecated features::

Porting to Python 3.3

* Porting Python code::
* Porting C code::
* Building C extensions::
* Command Line Switch Changes::

What’s New In Python 3.2

* PEP 384; Defining a Stable ABI: PEP 384 Defining a Stable ABI.
* PEP 389; Argparse Command Line Parsing Module: PEP 389 Argparse Command Line Parsing Module.
* PEP 391; Dictionary Based Configuration for Logging: PEP 391 Dictionary Based Configuration for Logging.
* PEP 3148; The concurrent.futures module: PEP 3148 The concurrent futures module.
* PEP 3147; PYC Repository Directories: PEP 3147 PYC Repository Directories.
* PEP 3149; ABI Version Tagged .so Files: PEP 3149 ABI Version Tagged so Files.
* PEP 3333; Python Web Server Gateway Interface v1.0.1: PEP 3333 Python Web Server Gateway Interface v1 0 1.
* Other Language Changes: Other Language Changes<12>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules.
* Multi-threading::
* Optimizations: Optimizations<11>.
* Unicode::
* Codecs::
* Documentation::
* IDLE::
* Code Repository::
* Build and C API Changes: Build and C API Changes<5>.
* Porting to Python 3.2: Porting to Python 3 2.

New, Improved, and Deprecated Modules

* email: email<6>.
* elementtree::
* functools: functools<7>.
* itertools: itertools<7>.
* collections: collections<8>.
* threading: threading<9>.
* datetime and time::
* math: math<10>.
* abc: abc<3>.
* io: io<7>.
* reprlib::
* logging: logging<8>.
* csv: csv<4>.
* contextlib: contextlib<8>.
* decimal and fractions::
* ftp::
* popen::
* select: select<3>.
* gzip and zipfile::
* tarfile: tarfile<10>.
* hashlib: hashlib<7>.
* ast: ast<5>.
* os: os<13>.
* shutil: shutil<8>.
* sqlite3: sqlite3<11>.
* html: html<3>.
* socket: socket<11>.
* ssl: ssl<12>.
* nntp::
* certificates::
* imaplib: imaplib<4>.
* http.client: http client<4>.
* unittest: unittest<11>.
* random: random<5>.
* poplib: poplib<4>.
* asyncore: asyncore<2>.
* tempfile: tempfile<5>.
* inspect: inspect<10>.
* pydoc: pydoc<6>.
* dis: dis<5>.
* dbm: dbm<7>.
* ctypes: ctypes<3>.
* site: site<4>.
* sysconfig: sysconfig<3>.
* pdb: pdb<8>.
* configparser: configparser<5>.
* urllib.parse: urllib parse<6>.
* mailbox::
* turtledemo::

What’s New In Python 3.1

* PEP 372; Ordered Dictionaries: PEP 372 Ordered Dictionaries.
* PEP 378; Format Specifier for Thousands Separator: PEP 378 Format Specifier for Thousands Separator.
* Other Language Changes: Other Language Changes<13>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<2>.
* Optimizations: Optimizations<12>.
* IDLE: IDLE<2>.
* Build and C API Changes: Build and C API Changes<6>.
* Porting to Python 3.1: Porting to Python 3 1.

What’s New In Python 3.0

* Common Stumbling Blocks::
* Overview Of Syntax Changes::
* Changes Already Present In Python 2.6: Changes Already Present In Python 2 6.
* Library Changes::
* PEP 3101; A New Approach To String Formatting: PEP 3101 A New Approach To String Formatting.
* Changes To Exceptions::
* Miscellaneous Other Changes::
* Build and C API Changes: Build and C API Changes<7>.
* Performance::
* Porting To Python 3.0: Porting To Python 3 0.

Common Stumbling Blocks

* Print Is A Function::
* Views And Iterators Instead Of Lists::
* Ordering Comparisons::
* Integers::
* Text Vs. Data Instead Of Unicode Vs. 8-bit: Text Vs Data Instead Of Unicode Vs 8-bit.

Overview Of Syntax Changes

* New Syntax::
* Changed Syntax::
* Removed Syntax::

Miscellaneous Other Changes

* Operators And Special Methods::
* Builtins::

What’s New in Python 2.7

* The Future for Python 2.x: The Future for Python 2 x.
* Changes to the Handling of Deprecation Warnings::
* Python 3.1 Features: Python 3 1 Features.
* PEP 372; Adding an Ordered Dictionary to collections: PEP 372 Adding an Ordered Dictionary to collections.
* PEP 378; Format Specifier for Thousands Separator: PEP 378 Format Specifier for Thousands Separator<2>.
* PEP 389; The argparse Module for Parsing Command Lines: PEP 389 The argparse Module for Parsing Command Lines.
* PEP 391; Dictionary-Based Configuration For Logging: PEP 391 Dictionary-Based Configuration For Logging.
* PEP 3106; Dictionary Views: PEP 3106 Dictionary Views.
* PEP 3137; The memoryview Object: PEP 3137 The memoryview Object.
* Other Language Changes: Other Language Changes<14>.
* New and Improved Modules::
* Build and C API Changes: Build and C API Changes<8>.
* Other Changes and Fixes::
* Porting to Python 2.7: Porting to Python 2 7.
* New Features Added to Python 2.7 Maintenance Releases: New Features Added to Python 2 7 Maintenance Releases.
* Acknowledgements::

Other Language Changes

* Interpreter Changes::
* Optimizations: Optimizations<13>.

New and Improved Modules

* New module; importlib: New module importlib.
* New module; sysconfig: New module sysconfig.
* ttk; Themed Widgets for Tk: ttk Themed Widgets for Tk.
* Updated module; unittest: Updated module unittest.
* Updated module; ElementTree 1.3: Updated module ElementTree 1 3.

Build and C API Changes

* Capsules::
* Port-Specific Changes; Windows: Port-Specific Changes Windows.
* Port-Specific Changes; Mac OS X: Port-Specific Changes Mac OS X.
* Port-Specific Changes; FreeBSD: Port-Specific Changes FreeBSD.

New Features Added to Python 2.7 Maintenance Releases

* Two new environment variables for debug mode::
* PEP 434; IDLE Enhancement Exception for All Branches: PEP 434 IDLE Enhancement Exception for All Branches.
* PEP 466; Network Security Enhancements for Python 2.7: PEP 466 Network Security Enhancements for Python 2 7.
* PEP 477; Backport ensurepip (PEP 453) to Python 2.7: PEP 477 Backport ensurepip PEP 453 to Python 2 7.
* PEP 476; Enabling certificate verification by default for stdlib http clients: PEP 476 Enabling certificate verification by default for stdlib http clients<2>.
* PEP 493; HTTPS verification migration tools for Python 2.7: PEP 493 HTTPS verification migration tools for Python 2 7.
* New make regen-all build target: New make regen-all build target<3>.
* Removal of make touch build target: Removal of make touch build target<3>.

PEP 477: Backport ensurepip (PEP 453) to Python 2.7

* Bootstrapping pip By Default: Bootstrapping pip By Default<2>.
* Documentation Changes: Documentation Changes<2>.

What’s New in Python 2.6

* Python 3.0: Python 3 0.
* Changes to the Development Process::
* PEP 343; The ‘with’ statement: PEP 343 The ‘with’ statement.
* PEP 366; Explicit Relative Imports From a Main Module: PEP 366 Explicit Relative Imports From a Main Module.
* PEP 370; Per-user site-packages Directory: PEP 370 Per-user site-packages Directory.
* PEP 371; The multiprocessing Package: PEP 371 The multiprocessing Package.
* PEP 3101; Advanced String Formatting: PEP 3101 Advanced String Formatting.
* PEP 3105; print As a Function: PEP 3105 print As a Function.
* PEP 3110; Exception-Handling Changes: PEP 3110 Exception-Handling Changes.
* PEP 3112; Byte Literals: PEP 3112 Byte Literals.
* PEP 3116; New I/O Library: PEP 3116 New I/O Library.
* PEP 3118; Revised Buffer Protocol: PEP 3118 Revised Buffer Protocol.
* PEP 3119; Abstract Base Classes: PEP 3119 Abstract Base Classes.
* PEP 3127; Integer Literal Support and Syntax: PEP 3127 Integer Literal Support and Syntax.
* PEP 3129; Class Decorators: PEP 3129 Class Decorators.
* PEP 3141; A Type Hierarchy for Numbers: PEP 3141 A Type Hierarchy for Numbers.
* Other Language Changes: Other Language Changes<15>.
* New and Improved Modules: New and Improved Modules<2>.
* Deprecations and Removals::
* Build and C API Changes: Build and C API Changes<9>.
* Porting to Python 2.6: Porting to Python 2 6.
* Acknowledgements: Acknowledgements<2>.

Changes to the Development Process

* New Issue Tracker; Roundup: New Issue Tracker Roundup.
* New Documentation Format; reStructuredText Using Sphinx: New Documentation Format reStructuredText Using Sphinx.

PEP 343: The ‘with’ statement

* Writing Context Managers::
* The contextlib module::

PEP 3141: A Type Hierarchy for Numbers

* The fractions Module::

Other Language Changes

* Optimizations: Optimizations<14>.
* Interpreter Changes: Interpreter Changes<2>.

New and Improved Modules

* The ast module::
* The future_builtins module::
* The json module; JavaScript Object Notation: The json module JavaScript Object Notation.
* The plistlib module; A Property-List Parser: The plistlib module A Property-List Parser.
* ctypes Enhancements::
* Improved SSL Support::

Build and C API Changes

* Port-Specific Changes; Windows: Port-Specific Changes Windows<2>.
* Port-Specific Changes; Mac OS X: Port-Specific Changes Mac OS X<2>.
* Port-Specific Changes; IRIX: Port-Specific Changes IRIX.

What’s New in Python 2.5

* PEP 308; Conditional Expressions: PEP 308 Conditional Expressions.
* PEP 309; Partial Function Application: PEP 309 Partial Function Application.
* PEP 314; Metadata for Python Software Packages v1.1: PEP 314 Metadata for Python Software Packages v1 1.
* PEP 328; Absolute and Relative Imports: PEP 328 Absolute and Relative Imports.
* PEP 338; Executing Modules as Scripts: PEP 338 Executing Modules as Scripts.
* PEP 341; Unified try/except/finally: PEP 341 Unified try/except/finally.
* PEP 342; New Generator Features: PEP 342 New Generator Features.
* PEP 343; The ‘with’ statement: PEP 343 The ‘with’ statement<2>.
* PEP 352; Exceptions as New-Style Classes: PEP 352 Exceptions as New-Style Classes.
* PEP 353; Using ssize_t as the index type: PEP 353 Using ssize_t as the index type.
* PEP 357; The ‘__index__’ method: PEP 357 The ‘__index__’ method.
* Other Language Changes: Other Language Changes<16>.
* New, Improved, and Removed Modules: New Improved and Removed Modules.
* Build and C API Changes: Build and C API Changes<10>.
* Porting to Python 2.5: Porting to Python 2 5.
* Acknowledgements: Acknowledgements<3>.

PEP 343: The ‘with’ statement

* Writing Context Managers: Writing Context Managers<2>.
* The contextlib module: The contextlib module<2>.

Other Language Changes

* Interactive Interpreter Changes::
* Optimizations: Optimizations<15>.

New, Improved, and Removed Modules

* The ctypes package::
* The ElementTree package::
* The hashlib package::
* The sqlite3 package::
* The wsgiref package::

Build and C API Changes

* Port-Specific Changes::

What’s New in Python 2.4

* PEP 218; Built-In Set Objects: PEP 218 Built-In Set Objects.
* PEP 237; Unifying Long Integers and Integers: PEP 237 Unifying Long Integers and Integers.
* PEP 289; Generator Expressions: PEP 289 Generator Expressions.
* PEP 292; Simpler String Substitutions: PEP 292 Simpler String Substitutions.
* PEP 318; Decorators for Functions and Methods: PEP 318 Decorators for Functions and Methods.
* PEP 322; Reverse Iteration: PEP 322 Reverse Iteration.
* PEP 324; New subprocess Module: PEP 324 New subprocess Module.
* PEP 327; Decimal Data Type: PEP 327 Decimal Data Type.
* PEP 328; Multi-line Imports: PEP 328 Multi-line Imports.
* PEP 331; Locale-Independent Float/String Conversions: PEP 331 Locale-Independent Float/String Conversions.
* Other Language Changes: Other Language Changes<17>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<3>.
* Build and C API Changes: Build and C API Changes<11>.
* Porting to Python 2.4: Porting to Python 2 4.
* Acknowledgements: Acknowledgements<4>.

PEP 327: Decimal Data Type

* Why is Decimal needed?::
* The Decimal type::
* The Context type::

Other Language Changes

* Optimizations: Optimizations<16>.

New, Improved, and Deprecated Modules

* cookielib::
* doctest: doctest<5>.

Build and C API Changes

* Port-Specific Changes: Port-Specific Changes<2>.

What’s New in Python 2.3

* PEP 218; A Standard Set Datatype: PEP 218 A Standard Set Datatype.
* PEP 255; Simple Generators: PEP 255 Simple Generators.
* PEP 263; Source Code Encodings: PEP 263 Source Code Encodings.
* PEP 273; Importing Modules from ZIP Archives: PEP 273 Importing Modules from ZIP Archives.
* PEP 277; Unicode file name support for Windows NT: PEP 277 Unicode file name support for Windows NT.
* PEP 278; Universal Newline Support: PEP 278 Universal Newline Support.
* PEP 279; enumerate(): PEP 279 enumerate.
* PEP 282; The logging Package: PEP 282 The logging Package.
* PEP 285; A Boolean Type: PEP 285 A Boolean Type.
* PEP 293; Codec Error Handling Callbacks: PEP 293 Codec Error Handling Callbacks.
* PEP 301; Package Index and Metadata for Distutils: PEP 301 Package Index and Metadata for Distutils.
* PEP 302; New Import Hooks: PEP 302 New Import Hooks.
* PEP 305; Comma-separated Files: PEP 305 Comma-separated Files.
* PEP 307; Pickle Enhancements: PEP 307 Pickle Enhancements.
* Extended Slices::
* Other Language Changes: Other Language Changes<18>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<4>.
* Pymalloc; A Specialized Object Allocator: Pymalloc A Specialized Object Allocator.
* Build and C API Changes: Build and C API Changes<12>.
* Other Changes and Fixes: Other Changes and Fixes<2>.
* Porting to Python 2.3: Porting to Python 2 3.
* Acknowledgements: Acknowledgements<5>.

Other Language Changes

* String Changes::
* Optimizations: Optimizations<17>.

New, Improved, and Deprecated Modules

* Date/Time Type::
* The optparse Module::

Build and C API Changes

* Port-Specific Changes: Port-Specific Changes<3>.

What’s New in Python 2.2

* Introduction::
* PEPs 252 and 253; Type and Class Changes: PEPs 252 and 253 Type and Class Changes.
* PEP 234; Iterators: PEP 234 Iterators.
* PEP 255; Simple Generators: PEP 255 Simple Generators<2>.
* PEP 237; Unifying Long Integers and Integers: PEP 237 Unifying Long Integers and Integers<2>.
* PEP 238; Changing the Division Operator: PEP 238 Changing the Division Operator.
* Unicode Changes::
* PEP 227; Nested Scopes: PEP 227 Nested Scopes.
* New and Improved Modules: New and Improved Modules<3>.
* Interpreter Changes and Fixes::
* Other Changes and Fixes: Other Changes and Fixes<3>.
* Acknowledgements: Acknowledgements<6>.

PEPs 252 and 253: Type and Class Changes

* Old and New Classes::
* Descriptors::
* Multiple Inheritance; The Diamond Rule: Multiple Inheritance The Diamond Rule.
* Attribute Access::
* Related Links::

What’s New in Python 2.1

* Introduction: Introduction<2>.
* PEP 227; Nested Scopes: PEP 227 Nested Scopes<2>.
* PEP 236; __future__ Directives: PEP 236 __future__ Directives.
* PEP 207; Rich Comparisons: PEP 207 Rich Comparisons.
* PEP 230; Warning Framework: PEP 230 Warning Framework.
* PEP 229; New Build System: PEP 229 New Build System.
* PEP 205; Weak References: PEP 205 Weak References.
* PEP 232; Function Attributes: PEP 232 Function Attributes.
* PEP 235; Importing Modules on Case-Insensitive Platforms: PEP 235 Importing Modules on Case-Insensitive Platforms.
* PEP 217; Interactive Display Hook: PEP 217 Interactive Display Hook.
* PEP 208; New Coercion Model: PEP 208 New Coercion Model.
* PEP 241; Metadata in Python Packages: PEP 241 Metadata in Python Packages.
* New and Improved Modules: New and Improved Modules<4>.
* Other Changes and Fixes: Other Changes and Fixes<4>.
* Acknowledgements: Acknowledgements<7>.

What’s New in Python 2.0

* Introduction: Introduction<3>.
* What About Python 1.6?: What About Python 1 6?.
* New Development Process::
* Unicode: Unicode<2>.
* List Comprehensions::
* Augmented Assignment::
* String Methods::
* Garbage Collection of Cycles::
* Other Core Changes::
* Porting to 2.0: Porting to 2 0.
* Extending/Embedding Changes::
* Distutils; Making Modules Easy to Install: Distutils Making Modules Easy to Install.
* XML Modules::
* Module changes::
* New modules::
* IDLE Improvements::
* Deleted and Deprecated Modules::
* Acknowledgements: Acknowledgements<8>.

Other Core Changes

* Minor Language Changes::
* Changes to Built-in Functions::

XML Modules

* SAX2 Support::
* DOM Support::
* Relationship to PyXML::

Changelog

* Python 3.13.13 final: Python 3 13 13 final.
* Python 3.13.12 final: Python 3 13 12 final.
* Python 3.13.11 final: Python 3 13 11 final.
* Python 3.13.10 final: Python 3 13 10 final.
* Python 3.13.9 final: Python 3 13 9 final.
* Python 3.13.8 final: Python 3 13 8 final.
* Python 3.13.7 final: Python 3 13 7 final.
* Python 3.13.6 final: Python 3 13 6 final.
* Python 3.13.5 final: Python 3 13 5 final.
* Python 3.13.4 final: Python 3 13 4 final.
* Python 3.13.3 final: Python 3 13 3 final.
* Python 3.13.2 final: Python 3 13 2 final.
* Python 3.13.1 final: Python 3 13 1 final.
* Python 3.13.0 final: Python 3 13 0 final.
* Python 3.13.0 release candidate 3: Python 3 13 0 release candidate 3.
* Python 3.13.0 release candidate 2: Python 3 13 0 release candidate 2.
* Python 3.13.0 release candidate 1: Python 3 13 0 release candidate 1.
* Python 3.13.0 beta 4: Python 3 13 0 beta 4.
* Python 3.13.0 beta 3: Python 3 13 0 beta 3.
* Python 3.13.0 beta 2: Python 3 13 0 beta 2.
* Python 3.13.0 beta 1: Python 3 13 0 beta 1.
* Python 3.13.0 alpha 6: Python 3 13 0 alpha 6.
* Python 3.13.0 alpha 5: Python 3 13 0 alpha 5.
* Python 3.13.0 alpha 4: Python 3 13 0 alpha 4.
* Python 3.13.0 alpha 3: Python 3 13 0 alpha 3.
* Python 3.13.0 alpha 2: Python 3 13 0 alpha 2.
* Python 3.13.0 alpha 1: Python 3 13 0 alpha 1.
* Python 3.12.0 beta 1: Python 3 12 0 beta 1.
* Python 3.12.0 alpha 7: Python 3 12 0 alpha 7.
* Python 3.12.0 alpha 6: Python 3 12 0 alpha 6.
* Python 3.12.0 alpha 5: Python 3 12 0 alpha 5.
* Python 3.12.0 alpha 4: Python 3 12 0 alpha 4.
* Python 3.12.0 alpha 3: Python 3 12 0 alpha 3.
* Python 3.12.0 alpha 2: Python 3 12 0 alpha 2.
* Python 3.12.0 alpha 1: Python 3 12 0 alpha 1.
* Python 3.11.0 beta 1: Python 3 11 0 beta 1.
* Python 3.11.0 alpha 7: Python 3 11 0 alpha 7.
* Python 3.11.0 alpha 6: Python 3 11 0 alpha 6.
* Python 3.11.0 alpha 5: Python 3 11 0 alpha 5.
* Python 3.11.0 alpha 4: Python 3 11 0 alpha 4.
* Python 3.11.0 alpha 3: Python 3 11 0 alpha 3.
* Python 3.11.0 alpha 2: Python 3 11 0 alpha 2.
* Python 3.11.0 alpha 1: Python 3 11 0 alpha 1.
* Python 3.10.0 beta 1: Python 3 10 0 beta 1.
* Python 3.10.0 alpha 7: Python 3 10 0 alpha 7.
* Python 3.10.0 alpha 6: Python 3 10 0 alpha 6.
* Python 3.10.0 alpha 5: Python 3 10 0 alpha 5.
* Python 3.10.0 alpha 4: Python 3 10 0 alpha 4.
* Python 3.10.0 alpha 3: Python 3 10 0 alpha 3.
* Python 3.10.0 alpha 2: Python 3 10 0 alpha 2.
* Python 3.10.0 alpha 1: Python 3 10 0 alpha 1.
* Python 3.9.0 beta 1: Python 3 9 0 beta 1.
* Python 3.9.0 alpha 6: Python 3 9 0 alpha 6.
* Python 3.9.0 alpha 5: Python 3 9 0 alpha 5.
* Python 3.9.0 alpha 4: Python 3 9 0 alpha 4.
* Python 3.9.0 alpha 3: Python 3 9 0 alpha 3.
* Python 3.9.0 alpha 2: Python 3 9 0 alpha 2.
* Python 3.9.0 alpha 1: Python 3 9 0 alpha 1.
* Python 3.8.0 beta 1: Python 3 8 0 beta 1.
* Python 3.8.0 alpha 4: Python 3 8 0 alpha 4.
* Python 3.8.0 alpha 3: Python 3 8 0 alpha 3.
* Python 3.8.0 alpha 2: Python 3 8 0 alpha 2.
* Python 3.8.0 alpha 1: Python 3 8 0 alpha 1.
* Python 3.7.0 final: Python 3 7 0 final.
* Python 3.7.0 release candidate 1: Python 3 7 0 release candidate 1.
* Python 3.7.0 beta 5: Python 3 7 0 beta 5.
* Python 3.7.0 beta 4: Python 3 7 0 beta 4.
* Python 3.7.0 beta 3: Python 3 7 0 beta 3.
* Python 3.7.0 beta 2: Python 3 7 0 beta 2.
* Python 3.7.0 beta 1: Python 3 7 0 beta 1.
* Python 3.7.0 alpha 4: Python 3 7 0 alpha 4.
* Python 3.7.0 alpha 3: Python 3 7 0 alpha 3.
* Python 3.7.0 alpha 2: Python 3 7 0 alpha 2.
* Python 3.7.0 alpha 1: Python 3 7 0 alpha 1.
* Python 3.6.6 final: Python 3 6 6 final.
* Python 3.6.6 release candidate 1: Python 3 6 6 release candidate 1.
* Python 3.6.5 final: Python 3 6 5 final.
* Python 3.6.5 release candidate 1: Python 3 6 5 release candidate 1.
* Python 3.6.4 final: Python 3 6 4 final.
* Python 3.6.4 release candidate 1: Python 3 6 4 release candidate 1.
* Python 3.6.3 final: Python 3 6 3 final.
* Python 3.6.3 release candidate 1: Python 3 6 3 release candidate 1.
* Python 3.6.2 final: Python 3 6 2 final.
* Python 3.6.2 release candidate 2: Python 3 6 2 release candidate 2.
* Python 3.6.2 release candidate 1: Python 3 6 2 release candidate 1.
* Python 3.6.1 final: Python 3 6 1 final.
* Python 3.6.1 release candidate 1: Python 3 6 1 release candidate 1.
* Python 3.6.0 final: Python 3 6 0 final.
* Python 3.6.0 release candidate 2: Python 3 6 0 release candidate 2.
* Python 3.6.0 release candidate 1: Python 3 6 0 release candidate 1.
* Python 3.6.0 beta 4: Python 3 6 0 beta 4.
* Python 3.6.0 beta 3: Python 3 6 0 beta 3.
* Python 3.6.0 beta 2: Python 3 6 0 beta 2.
* Python 3.6.0 beta 1: Python 3 6 0 beta 1.
* Python 3.6.0 alpha 4: Python 3 6 0 alpha 4.
* Python 3.6.0 alpha 3: Python 3 6 0 alpha 3.
* Python 3.6.0 alpha 2: Python 3 6 0 alpha 2.
* Python 3.6.0 alpha 1: Python 3 6 0 alpha 1.
* Python 3.5.5 final: Python 3 5 5 final.
* Python 3.5.5 release candidate 1: Python 3 5 5 release candidate 1.
* Python 3.5.4 final: Python 3 5 4 final.
* Python 3.5.4 release candidate 1: Python 3 5 4 release candidate 1.
* Python 3.5.3 final: Python 3 5 3 final.
* Python 3.5.3 release candidate 1: Python 3 5 3 release candidate 1.
* Python 3.5.2 final: Python 3 5 2 final.
* Python 3.5.2 release candidate 1: Python 3 5 2 release candidate 1.
* Python 3.5.1 final: Python 3 5 1 final.
* Python 3.5.1 release candidate 1: Python 3 5 1 release candidate 1.
* Python 3.5.0 final: Python 3 5 0 final.
* Python 3.5.0 release candidate 4: Python 3 5 0 release candidate 4.
* Python 3.5.0 release candidate 3: Python 3 5 0 release candidate 3.
* Python 3.5.0 release candidate 2: Python 3 5 0 release candidate 2.
* Python 3.5.0 release candidate 1: Python 3 5 0 release candidate 1.
* Python 3.5.0 beta 4: Python 3 5 0 beta 4.
* Python 3.5.0 beta 3: Python 3 5 0 beta 3.
* Python 3.5.0 beta 2: Python 3 5 0 beta 2.
* Python 3.5.0 beta 1: Python 3 5 0 beta 1.
* Python 3.5.0 alpha 4: Python 3 5 0 alpha 4.
* Python 3.5.0 alpha 3: Python 3 5 0 alpha 3.
* Python 3.5.0 alpha 2: Python 3 5 0 alpha 2.
* Python 3.5.0 alpha 1: Python 3 5 0 alpha 1.

Python 3.13.13 final

* macOS::
* Windows::
* Tests::
* Security::
* Library::
* Documentation: Documentation<2>.
* Core and Builtins::
* Build::

Python 3.13.12 final

* Windows: Windows<2>.
* Tools/Demos::
* Tests: Tests<2>.
* Security: Security<2>.
* Library: Library<2>.
* IDLE: IDLE<3>.
* Documentation: Documentation<3>.
* Core and Builtins: Core and Builtins<2>.
* C API::
* Build: Build<2>.

Python 3.13.11 final

* Security: Security<3>.
* Library: Library<3>.
* Core and Builtins: Core and Builtins<3>.

Python 3.13.10 final

* Tools/Demos: Tools/Demos<2>.
* Tests: Tests<3>.
* Security: Security<4>.
* Library: Library<4>.
* IDLE: IDLE<4>.
* Documentation: Documentation<4>.
* Core and Builtins: Core and Builtins<4>.
* C API: C API<2>.

Python 3.13.9 final

* Library: Library<5>.

Python 3.13.8 final

* macOS: macOS<2>.
* Windows: Windows<3>.
* Tools/Demos: Tools/Demos<3>.
* Tests: Tests<4>.
* Security: Security<5>.
* Library: Library<6>.
* Core and Builtins: Core and Builtins<5>.
* C API: C API<3>.
* Build: Build<3>.

Python 3.13.7 final

* Library: Library<7>.
* Documentation: Documentation<5>.
* Core and Builtins: Core and Builtins<6>.

Python 3.13.6 final

* macOS: macOS<3>.
* Windows: Windows<4>.
* Tools/Demos: Tools/Demos<4>.
* Tests: Tests<5>.
* Security: Security<6>.
* Library: Library<8>.
* Documentation: Documentation<6>.
* Core and Builtins: Core and Builtins<7>.
* Build: Build<4>.

Python 3.13.5 final

* Windows: Windows<5>.
* Tests: Tests<6>.
* Library: Library<9>.
* Core and Builtins: Core and Builtins<8>.
* C API: C API<4>.

Python 3.13.4 final

* Windows: Windows<6>.
* Tests: Tests<7>.
* Security: Security<7>.
* Library: Library<10>.
* IDLE: IDLE<5>.
* Documentation: Documentation<7>.
* Library: Library<11>.
* Core and Builtins: Core and Builtins<9>.
* Library: Library<12>.
* Core and Builtins: Core and Builtins<10>.
* C API: C API<5>.
* Build: Build<5>.

Python 3.13.3 final

* macOS: macOS<4>.
* Windows: Windows<7>.
* Tools/Demos: Tools/Demos<5>.
* Tests: Tests<8>.
* Security: Security<8>.
* Library: Library<13>.
* IDLE: IDLE<6>.
* Documentation: Documentation<8>.
* Core and Builtins: Core and Builtins<11>.
* Library: Library<14>.
* Core and Builtins: Core and Builtins<12>.
* C API: C API<6>.
* Build: Build<6>.

Python 3.13.2 final

* macOS: macOS<5>.
* Windows: Windows<8>.
* Tools/Demos: Tools/Demos<6>.
* Tests: Tests<9>.
* Security: Security<9>.
* Library: Library<15>.
* Documentation: Documentation<9>.
* Library: Library<16>.
* Core and Builtins: Core and Builtins<13>.
* C API: C API<7>.
* Build: Build<7>.

Python 3.13.1 final

* macOS: macOS<6>.
* Windows: Windows<9>.
* Tools/Demos: Tools/Demos<7>.
* Tests: Tests<10>.
* Security: Security<10>.
* Library: Library<17>.
* IDLE: IDLE<7>.
* Documentation: Documentation<10>.
* Core and Builtins: Core and Builtins<14>.
* Library: Library<18>.
* Core and Builtins: Core and Builtins<15>.
* Library: Library<19>.
* Core and Builtins: Core and Builtins<16>.
* C API: C API<8>.
* Build: Build<8>.

Python 3.13.0 final

* Library: Library<20>.
* Core and Builtins: Core and Builtins<17>.

Python 3.13.0 release candidate 3

* macOS: macOS<7>.
* Windows: Windows<10>.
* Tests: Tests<11>.
* Library: Library<21>.
* IDLE: IDLE<8>.
* Documentation: Documentation<11>.
* Core and Builtins: Core and Builtins<18>.
* C API: C API<9>.
* Build: Build<9>.

Python 3.13.0 release candidate 2

* macOS: macOS<8>.
* Windows: Windows<11>.
* Tools/Demos: Tools/Demos<8>.
* Tests: Tests<12>.
* Security: Security<11>.
* Library: Library<22>.
* IDLE: IDLE<9>.
* Library: Library<23>.
* Core and Builtins: Core and Builtins<19>.
* C API: C API<10>.
* Build: Build<10>.

Python 3.13.0 release candidate 1

* Tests: Tests<13>.
* Security: Security<12>.
* Library: Library<24>.
* IDLE: IDLE<10>.
* Core and Builtins: Core and Builtins<20>.
* C API: C API<11>.
* Build: Build<11>.

Python 3.13.0 beta 4

* Tests: Tests<14>.
* Library: Library<25>.
* IDLE: IDLE<11>.
* Documentation: Documentation<12>.
* Core and Builtins: Core and Builtins<21>.
* C API: C API<12>.
* Build: Build<12>.

Python 3.13.0 beta 3

* Core and Builtins: Core and Builtins<22>.
* Library: Library<26>.
* Core and Builtins: Core and Builtins<23>.
* Library: Library<27>.
* Build: Build<13>.
* C API: C API<13>.

Python 3.13.0 beta 2

* Security: Security<13>.
* Core and Builtins: Core and Builtins<24>.
* Library: Library<28>.
* Tests: Tests<15>.
* Build: Build<14>.
* Windows: Windows<12>.
* C API: C API<14>.

Python 3.13.0 beta 1

* Security: Security<14>.
* Core and Builtins: Core and Builtins<25>.
* Library: Library<29>.
* Core and Builtins: Core and Builtins<26>.
* Library: Library<30>.
* Documentation: Documentation<13>.
* Build: Build<15>.
* Windows: Windows<13>.
* macOS: macOS<9>.
* IDLE: IDLE<12>.
* C API: C API<15>.

Python 3.13.0 alpha 6

* Core and Builtins: Core and Builtins<27>.
* Library: Library<31>.
* Core and Builtins: Core and Builtins<28>.
* Library: Library<32>.
* Documentation: Documentation<14>.
* Tests: Tests<16>.
* Build: Build<16>.
* Windows: Windows<14>.
* C API: C API<16>.

Python 3.13.0 alpha 5

* Security: Security<15>.
* Core and Builtins: Core and Builtins<29>.
* Library: Library<33>.
* Core and Builtins: Core and Builtins<30>.
* Library: Library<34>.
* Core and Builtins: Core and Builtins<31>.
* Library: Library<35>.
* Documentation: Documentation<15>.
* Tests: Tests<17>.
* Build: Build<17>.
* Windows: Windows<15>.
* macOS: macOS<10>.
* IDLE: IDLE<13>.
* Tools/Demos: Tools/Demos<9>.
* C API: C API<17>.

Python 3.13.0 alpha 4

* Security: Security<16>.
* Core and Builtins: Core and Builtins<32>.
* Library: Library<36>.
* Documentation: Documentation<16>.
* Tests: Tests<18>.
* Build: Build<18>.
* Windows: Windows<16>.
* macOS: macOS<11>.
* IDLE: IDLE<14>.
* Tools/Demos: Tools/Demos<10>.
* C API: C API<18>.

Python 3.13.0 alpha 3

* Security: Security<17>.
* Core and Builtins: Core and Builtins<33>.
* Library: Library<37>.
* Documentation: Documentation<17>.
* Tests: Tests<19>.
* Build: Build<19>.
* Windows: Windows<17>.
* macOS: macOS<12>.
* IDLE: IDLE<15>.
* C API: C API<19>.

Python 3.13.0 alpha 2

* Core and Builtins: Core and Builtins<34>.
* Library: Library<38>.
* Tests: Tests<20>.
* Build: Build<20>.
* Windows: Windows<18>.
* macOS: macOS<13>.
* IDLE: IDLE<16>.
* Tools/Demos: Tools/Demos<11>.
* C API: C API<20>.

Python 3.13.0 alpha 1

* Security: Security<18>.
* Core and Builtins: Core and Builtins<35>.
* Library: Library<39>.
* Documentation: Documentation<18>.
* Tests: Tests<21>.
* Build: Build<21>.
* Windows: Windows<19>.
* macOS: macOS<14>.
* IDLE: IDLE<17>.
* Tools/Demos: Tools/Demos<12>.
* C API: C API<21>.

Python 3.12.0 beta 1

* Security: Security<19>.
* Library: Library<40>.
* Core and Builtins: Core and Builtins<36>.
* Library: Library<41>.
* Core and Builtins: Core and Builtins<37>.
* Library: Library<42>.
* Core and Builtins: Core and Builtins<38>.
* Library: Library<43>.
* Documentation: Documentation<19>.
* Tests: Tests<22>.
* Build: Build<22>.
* Windows: Windows<20>.
* macOS: macOS<15>.
* IDLE: IDLE<18>.
* Tools/Demos: Tools/Demos<13>.
* C API: C API<22>.

Python 3.12.0 alpha 7

* Core and Builtins: Core and Builtins<39>.
* Library: Library<44>.
* Core and Builtins: Core and Builtins<40>.
* Build: Build<23>.
* Core and Builtins: Core and Builtins<41>.
* Library: Library<45>.
* Documentation: Documentation<20>.
* Tests: Tests<23>.
* Build: Build<24>.
* Windows: Windows<21>.
* Tools/Demos: Tools/Demos<14>.
* C API: C API<23>.

Python 3.12.0 alpha 6

* Security: Security<20>.
* Core and Builtins: Core and Builtins<42>.
* Library: Library<46>.
* Documentation: Documentation<21>.
* Tests: Tests<24>.
* Build: Build<25>.
* Windows: Windows<22>.
* macOS: macOS<16>.
* C API: C API<24>.

Python 3.12.0 alpha 5

* Security: Security<21>.
* Core and Builtins: Core and Builtins<43>.
* Library: Library<47>.
* Documentation: Documentation<22>.
* Tests: Tests<25>.
* Build: Build<26>.
* Windows: Windows<23>.

Python 3.12.0 alpha 4

* Core and Builtins: Core and Builtins<44>.
* Library: Library<48>.
* Core and Builtins: Core and Builtins<45>.
* Library: Library<49>.
* Core and Builtins: Core and Builtins<46>.
* Library: Library<50>.
* Documentation: Documentation<23>.
* Tests: Tests<26>.
* Build: Build<27>.
* Windows: Windows<24>.
* macOS: macOS<17>.
* Tools/Demos: Tools/Demos<15>.
* C API: C API<25>.

Python 3.12.0 alpha 3

* Security: Security<22>.
* Core and Builtins: Core and Builtins<47>.
* Library: Library<51>.
* Core and Builtins: Core and Builtins<48>.
* Library: Library<52>.
* Documentation: Documentation<24>.
* Tests: Tests<27>.
* Build: Build<28>.
* Windows: Windows<25>.
* macOS: macOS<18>.
* Tools/Demos: Tools/Demos<16>.
* C API: C API<26>.

Python 3.12.0 alpha 2

* Security: Security<23>.
* Core and Builtins: Core and Builtins<49>.
* Build: Build<29>.
* Core and Builtins: Core and Builtins<50>.
* Library: Library<53>.
* Documentation: Documentation<25>.
* Tests: Tests<28>.
* Build: Build<30>.
* Windows: Windows<26>.
* macOS: macOS<19>.
* C API: C API<27>.

Python 3.12.0 alpha 1

* Security: Security<24>.
* Core and Builtins: Core and Builtins<51>.
* Library: Library<54>.
* Core and Builtins: Core and Builtins<52>.
* Library: Library<55>.
* Core and Builtins: Core and Builtins<53>.
* Library: Library<56>.
* Core and Builtins: Core and Builtins<54>.
* Library: Library<57>.
* Core and Builtins: Core and Builtins<55>.
* Library: Library<58>.
* Core and Builtins: Core and Builtins<56>.
* Library: Library<59>.
* Core and Builtins: Core and Builtins<57>.
* Library: Library<60>.
* Core and Builtins: Core and Builtins<58>.
* Library: Library<61>.
* Core and Builtins: Core and Builtins<59>.
* Library: Library<62>.
* Core and Builtins: Core and Builtins<60>.
* Library: Library<63>.
* Documentation: Documentation<26>.
* Tests: Tests<29>.
* Build: Build<31>.
* Windows: Windows<27>.
* macOS: macOS<20>.
* IDLE: IDLE<19>.
* Tools/Demos: Tools/Demos<17>.
* C API: C API<28>.

Python 3.11.0 beta 1

* Security: Security<25>.
* Core and Builtins: Core and Builtins<61>.
* Library: Library<64>.
* Core and Builtins: Core and Builtins<62>.
* Build: Build<32>.
* Core and Builtins: Core and Builtins<63>.
* Library: Library<65>.
* Documentation: Documentation<27>.
* Tests: Tests<30>.
* Build: Build<33>.
* Windows: Windows<28>.
* macOS: macOS<21>.
* Tools/Demos: Tools/Demos<18>.
* C API: C API<29>.

Python 3.11.0 alpha 7

* Core and Builtins: Core and Builtins<64>.
* Library: Library<66>.
* Core and Builtins: Core and Builtins<65>.
* Library: Library<67>.
* Core and Builtins: Core and Builtins<66>.
* Library: Library<68>.
* Documentation: Documentation<28>.
* Tests: Tests<31>.
* Build: Build<34>.
* Windows: Windows<29>.
* macOS: macOS<22>.
* Tools/Demos: Tools/Demos<19>.
* C API: C API<30>.

Python 3.11.0 alpha 6

* Core and Builtins: Core and Builtins<67>.
* Library: Library<69>.
* Core and Builtins: Core and Builtins<68>.
* Library: Library<70>.
* Core and Builtins: Core and Builtins<69>.
* Library: Library<71>.
* Core and Builtins: Core and Builtins<70>.
* Library: Library<72>.
* Documentation: Documentation<29>.
* Tests: Tests<32>.
* Build: Build<35>.
* Windows: Windows<30>.
* IDLE: IDLE<20>.
* C API: C API<31>.

Python 3.11.0 alpha 5

* Core and Builtins: Core and Builtins<71>.
* Library: Library<73>.
* Core and Builtins: Core and Builtins<72>.
* Library: Library<74>.
* Build: Build<36>.
* Core and Builtins: Core and Builtins<73>.
* Library: Library<75>.
* Documentation: Documentation<30>.
* Tests: Tests<33>.
* Build: Build<37>.
* Windows: Windows<31>.
* macOS: macOS<23>.
* IDLE: IDLE<21>.
* C API: C API<32>.

Python 3.11.0 alpha 4

* Core and Builtins: Core and Builtins<74>.
* Library: Library<76>.
* Core and Builtins: Core and Builtins<75>.
* Library: Library<77>.
* Core and Builtins: Core and Builtins<76>.
* Library: Library<78>.
* Core and Builtins: Core and Builtins<77>.
* Library: Library<79>.
* Documentation: Documentation<31>.
* Tests: Tests<34>.
* Build: Build<38>.
* Windows: Windows<32>.
* macOS: macOS<24>.
* C API: C API<33>.

Python 3.11.0 alpha 3

* Core and Builtins: Core and Builtins<78>.
* Library: Library<80>.
* Core and Builtins: Core and Builtins<79>.
* Library: Library<81>.
* Documentation: Documentation<32>.
* Tests: Tests<35>.
* Build: Build<39>.
* Windows: Windows<33>.
* macOS: macOS<25>.
* C API: C API<34>.

Python 3.11.0 alpha 2

* Core and Builtins: Core and Builtins<80>.
* Library: Library<82>.
* Documentation: Documentation<33>.
* Tests: Tests<36>.
* Build: Build<40>.
* Windows: Windows<34>.
* macOS: macOS<26>.
* IDLE: IDLE<22>.
* C API: C API<35>.

Python 3.11.0 alpha 1

* Security: Security<26>.
* Core and Builtins: Core and Builtins<81>.
* Library: Library<83>.
* Core and Builtins: Core and Builtins<82>.
* Library: Library<84>.
* Core and Builtins: Core and Builtins<83>.
* Library: Library<85>.
* Core and Builtins: Core and Builtins<84>.
* Library: Library<86>.
* Core and Builtins: Core and Builtins<85>.
* Library: Library<87>.
* Core and Builtins: Core and Builtins<86>.
* Library: Library<88>.
* Core and Builtins: Core and Builtins<87>.
* Library: Library<89>.
* Core and Builtins: Core and Builtins<88>.
* Library: Library<90>.
* Core and Builtins: Core and Builtins<89>.
* Library: Library<91>.
* Core and Builtins: Core and Builtins<90>.
* Library: Library<92>.
* Documentation: Documentation<34>.
* Tests: Tests<37>.
* Build: Build<41>.
* Windows: Windows<35>.
* macOS: macOS<27>.
* IDLE: IDLE<23>.
* Tools/Demos: Tools/Demos<20>.
* C API: C API<36>.

Python 3.10.0 beta 1

* Security: Security<27>.
* Core and Builtins: Core and Builtins<91>.
* Library: Library<93>.
* Core and Builtins: Core and Builtins<92>.
* Library: Library<94>.
* Core and Builtins: Core and Builtins<93>.
* Library: Library<95>.
* Documentation: Documentation<35>.
* Tests: Tests<38>.
* Build: Build<42>.
* Windows: Windows<36>.
* macOS: macOS<28>.
* IDLE: IDLE<24>.
* C API: C API<37>.

Python 3.10.0 alpha 7

* Security: Security<28>.
* Core and Builtins: Core and Builtins<94>.
* Library: Library<96>.
* Core and Builtins: Core and Builtins<95>.
* Library: Library<97>.
* Documentation: Documentation<36>.
* Tests: Tests<39>.
* Build: Build<43>.
* Windows: Windows<37>.
* IDLE: IDLE<25>.
* C API: C API<38>.

Python 3.10.0 alpha 6

* Security: Security<29>.
* Core and Builtins: Core and Builtins<96>.
* Library: Library<98>.
* Core and Builtins: Core and Builtins<97>.
* Library: Library<99>.
* Core and Builtins: Core and Builtins<98>.
* Library: Library<100>.
* Documentation: Documentation<37>.
* Tests: Tests<40>.
* Build: Build<44>.
* Windows: Windows<38>.
* macOS: macOS<29>.
* IDLE: IDLE<26>.
* C API: C API<39>.

Python 3.10.0 alpha 5

* Security: Security<30>.
* Core and Builtins: Core and Builtins<99>.
* Library: Library<101>.
* Core and Builtins: Core and Builtins<100>.
* Library: Library<102>.
* Documentation: Documentation<38>.
* Tests: Tests<41>.
* Build: Build<45>.
* Windows: Windows<39>.
* macOS: macOS<30>.
* IDLE: IDLE<27>.
* C API: C API<40>.

Python 3.10.0 alpha 4

* Core and Builtins: Core and Builtins<101>.
* Library: Library<103>.
* Core and Builtins: Core and Builtins<102>.
* Library: Library<104>.
* Core and Builtins: Core and Builtins<103>.
* Library: Library<105>.
* Documentation: Documentation<39>.
* Tests: Tests<42>.
* Build: Build<46>.
* macOS: macOS<31>.
* Tools/Demos: Tools/Demos<21>.
* C API: C API<41>.

Python 3.10.0 alpha 3

* Security: Security<31>.
* Core and Builtins: Core and Builtins<104>.
* Library: Library<106>.
* Core and Builtins: Core and Builtins<105>.
* Library: Library<107>.
* Core and Builtins: Core and Builtins<106>.
* Library: Library<108>.
* Core and Builtins: Core and Builtins<107>.
* Library: Library<109>.
* Documentation: Documentation<40>.
* Tests: Tests<43>.
* Build: Build<47>.
* Windows: Windows<40>.
* macOS: macOS<32>.
* IDLE: IDLE<28>.
* Tools/Demos: Tools/Demos<22>.
* C API: C API<42>.

Python 3.10.0 alpha 2

* Security: Security<32>.
* Core and Builtins: Core and Builtins<108>.
* Library: Library<110>.
* Core and Builtins: Core and Builtins<109>.
* Library: Library<111>.
* Documentation: Documentation<41>.
* Tests: Tests<44>.
* Build: Build<48>.
* Windows: Windows<41>.
* macOS: macOS<33>.
* IDLE: IDLE<29>.
* C API: C API<43>.

Python 3.10.0 alpha 1

* Security: Security<33>.
* Core and Builtins: Core and Builtins<110>.
* Library: Library<112>.
* Core and Builtins: Core and Builtins<111>.
* Library: Library<113>.
* Core and Builtins: Core and Builtins<112>.
* Library: Library<114>.
* Core and Builtins: Core and Builtins<113>.
* Library: Library<115>.
* Core and Builtins: Core and Builtins<114>.
* Library: Library<116>.
* Core and Builtins: Core and Builtins<115>.
* Library: Library<117>.
* Core and Builtins: Core and Builtins<116>.
* Library: Library<118>.
* Core and Builtins: Core and Builtins<117>.
* Library: Library<119>.
* Core and Builtins: Core and Builtins<118>.
* Library: Library<120>.
* Core and Builtins: Core and Builtins<119>.
* Library: Library<121>.
* Core and Builtins: Core and Builtins<120>.
* Library: Library<122>.
* Core and Builtins: Core and Builtins<121>.
* Library: Library<123>.
* Core and Builtins: Core and Builtins<122>.
* Library: Library<124>.
* Core and Builtins: Core and Builtins<123>.
* Library: Library<125>.
* Core and Builtins: Core and Builtins<124>.
* Library: Library<126>.
* Documentation: Documentation<42>.
* Tests: Tests<45>.
* Build: Build<49>.
* Windows: Windows<42>.
* macOS: macOS<34>.
* IDLE: IDLE<30>.
* C API: C API<44>.

Python 3.9.0 beta 1

* Security: Security<34>.
* Core and Builtins: Core and Builtins<125>.
* Library: Library<127>.
* Documentation: Documentation<43>.
* Tests: Tests<46>.
* Build: Build<50>.
* Windows: Windows<43>.
* macOS: macOS<35>.
* Tools/Demos: Tools/Demos<23>.
* C API: C API<45>.

Python 3.9.0 alpha 6

* Security: Security<35>.
* Core and Builtins: Core and Builtins<126>.
* Library: Library<128>.
* Documentation: Documentation<44>.
* Tests: Tests<47>.
* Build: Build<51>.
* Windows: Windows<44>.
* macOS: macOS<36>.
* IDLE: IDLE<31>.
* Tools/Demos: Tools/Demos<24>.
* C API: C API<46>.

Python 3.9.0 alpha 5

* Security: Security<36>.
* Core and Builtins: Core and Builtins<127>.
* Library: Library<129>.
* Documentation: Documentation<45>.
* Tests: Tests<48>.
* Build: Build<52>.
* Windows: Windows<45>.
* macOS: macOS<37>.
* IDLE: IDLE<32>.
* Tools/Demos: Tools/Demos<25>.
* C API: C API<47>.

Python 3.9.0 alpha 4

* Security: Security<37>.
* Core and Builtins: Core and Builtins<128>.
* Library: Library<130>.
* Documentation: Documentation<46>.
* Tests: Tests<49>.
* Build: Build<53>.
* Windows: Windows<46>.
* IDLE: IDLE<33>.
* C API: C API<48>.

Python 3.9.0 alpha 3

* Core and Builtins: Core and Builtins<129>.
* Library: Library<131>.
* Documentation: Documentation<47>.
* Build: Build<54>.
* IDLE: IDLE<34>.
* C API: C API<49>.

Python 3.9.0 alpha 2

* Security: Security<38>.
* Core and Builtins: Core and Builtins<130>.
* Library: Library<132>.
* Documentation: Documentation<48>.
* Tests: Tests<50>.
* Build: Build<55>.
* Windows: Windows<47>.
* macOS: macOS<38>.
* IDLE: IDLE<35>.
* C API: C API<50>.

Python 3.9.0 alpha 1

* Security: Security<39>.
* Core and Builtins: Core and Builtins<131>.
* Library: Library<133>.
* Documentation: Documentation<49>.
* Tests: Tests<51>.
* Build: Build<56>.
* Windows: Windows<48>.
* macOS: macOS<39>.
* IDLE: IDLE<36>.
* Tools/Demos: Tools/Demos<26>.
* C API: C API<51>.

Python 3.8.0 beta 1

* Security: Security<40>.
* Core and Builtins: Core and Builtins<132>.
* Library: Library<134>.
* Documentation: Documentation<50>.
* Tests: Tests<52>.
* Build: Build<57>.
* Windows: Windows<49>.
* macOS: macOS<40>.
* IDLE: IDLE<37>.
* Tools/Demos: Tools/Demos<27>.
* C API: C API<52>.

Python 3.8.0 alpha 4

* Security: Security<41>.
* Core and Builtins: Core and Builtins<133>.
* Library: Library<135>.
* Documentation: Documentation<51>.
* Tests: Tests<53>.
* Build: Build<58>.
* Windows: Windows<50>.
* macOS: macOS<41>.
* IDLE: IDLE<38>.
* Tools/Demos: Tools/Demos<28>.
* C API: C API<53>.

Python 3.8.0 alpha 3

* Security: Security<42>.
* Core and Builtins: Core and Builtins<134>.
* Library: Library<136>.
* Documentation: Documentation<52>.
* Tests: Tests<54>.
* Build: Build<59>.
* Windows: Windows<51>.
* IDLE: IDLE<39>.
* Tools/Demos: Tools/Demos<29>.
* C API: C API<54>.

Python 3.8.0 alpha 2

* Core and Builtins: Core and Builtins<135>.
* Library: Library<137>.
* Documentation: Documentation<53>.
* Tests: Tests<55>.
* Windows: Windows<52>.
* IDLE: IDLE<40>.

Python 3.8.0 alpha 1

* Security: Security<43>.
* Core and Builtins: Core and Builtins<136>.
* Library: Library<138>.
* Documentation: Documentation<54>.
* Tests: Tests<56>.
* Build: Build<60>.
* Windows: Windows<53>.
* macOS: macOS<42>.
* IDLE: IDLE<41>.
* Tools/Demos: Tools/Demos<30>.
* C API: C API<55>.

Python 3.7.0 final

* Library: Library<139>.
* C API: C API<56>.

Python 3.7.0 release candidate 1

* Core and Builtins: Core and Builtins<137>.
* Library: Library<140>.
* Documentation: Documentation<55>.
* Build: Build<61>.
* Windows: Windows<54>.
* IDLE: IDLE<42>.

Python 3.7.0 beta 5

* Core and Builtins: Core and Builtins<138>.
* Library: Library<141>.
* Documentation: Documentation<56>.
* Tests: Tests<57>.
* Build: Build<62>.
* macOS: macOS<43>.
* IDLE: IDLE<43>.

Python 3.7.0 beta 4

* Core and Builtins: Core and Builtins<139>.
* Library: Library<142>.
* Documentation: Documentation<57>.
* Tests: Tests<58>.
* Build: Build<63>.
* Windows: Windows<55>.
* macOS: macOS<44>.
* IDLE: IDLE<44>.
* Tools/Demos: Tools/Demos<31>.

Python 3.7.0 beta 3

* Security: Security<44>.
* Core and Builtins: Core and Builtins<140>.
* Library: Library<143>.
* Documentation: Documentation<58>.
* Tests: Tests<59>.
* Build: Build<64>.
* Windows: Windows<56>.
* macOS: macOS<45>.
* IDLE: IDLE<45>.
* Tools/Demos: Tools/Demos<32>.
* C API: C API<57>.

Python 3.7.0 beta 2

* Security: Security<45>.
* Core and Builtins: Core and Builtins<141>.
* Library: Library<144>.
* Documentation: Documentation<59>.
* Tests: Tests<60>.
* Build: Build<65>.
* Windows: Windows<57>.
* macOS: macOS<46>.
* IDLE: IDLE<46>.
* Tools/Demos: Tools/Demos<33>.

Python 3.7.0 beta 1

* Core and Builtins: Core and Builtins<142>.
* Library: Library<145>.
* Documentation: Documentation<60>.
* Tests: Tests<61>.
* Build: Build<66>.
* Windows: Windows<58>.
* macOS: macOS<47>.
* C API: C API<58>.

Python 3.7.0 alpha 4

* Core and Builtins: Core and Builtins<143>.
* Library: Library<146>.
* Documentation: Documentation<61>.
* Tests: Tests<62>.
* Windows: Windows<59>.
* Tools/Demos: Tools/Demos<34>.
* C API: C API<59>.

Python 3.7.0 alpha 3

* Core and Builtins: Core and Builtins<144>.
* Library: Library<147>.
* Documentation: Documentation<62>.
* Tests: Tests<63>.
* Build: Build<67>.
* Windows: Windows<60>.
* macOS: macOS<48>.
* IDLE: IDLE<47>.
* Tools/Demos: Tools/Demos<35>.
* C API: C API<60>.

Python 3.7.0 alpha 2

* Core and Builtins: Core and Builtins<145>.
* Library: Library<148>.
* Documentation: Documentation<63>.
* Build: Build<68>.
* IDLE: IDLE<48>.
* C API: C API<61>.

Python 3.7.0 alpha 1

* Security: Security<46>.
* Core and Builtins: Core and Builtins<146>.
* Library: Library<149>.
* Documentation: Documentation<64>.
* Tests: Tests<64>.
* Build: Build<69>.
* Windows: Windows<61>.
* IDLE: IDLE<49>.
* Tools/Demos: Tools/Demos<36>.
* C API: C API<62>.

Python 3.6.6 release candidate 1

* Core and Builtins: Core and Builtins<147>.
* Library: Library<150>.
* Documentation: Documentation<65>.
* Tests: Tests<65>.
* Build: Build<70>.
* Windows: Windows<62>.
* macOS: macOS<49>.
* IDLE: IDLE<50>.
* Tools/Demos: Tools/Demos<37>.
* C API: C API<63>.

Python 3.6.5 final

* Tests: Tests<66>.
* Build: Build<71>.

Python 3.6.5 release candidate 1

* Security: Security<47>.
* Core and Builtins: Core and Builtins<148>.
* Library: Library<151>.
* Documentation: Documentation<66>.
* Tests: Tests<67>.
* Build: Build<72>.
* Windows: Windows<63>.
* macOS: macOS<50>.
* IDLE: IDLE<51>.
* Tools/Demos: Tools/Demos<38>.
* C API: C API<64>.

Python 3.6.4 release candidate 1

* Core and Builtins: Core and Builtins<149>.
* Library: Library<152>.
* Documentation: Documentation<67>.
* Tests: Tests<68>.
* Build: Build<73>.
* Windows: Windows<64>.
* macOS: macOS<51>.
* IDLE: IDLE<52>.
* Tools/Demos: Tools/Demos<39>.
* C API: C API<65>.

Python 3.6.3 final

* Library: Library<153>.
* Build: Build<74>.

Python 3.6.3 release candidate 1

* Security: Security<48>.
* Core and Builtins: Core and Builtins<150>.
* Library: Library<154>.
* Documentation: Documentation<68>.
* Tests: Tests<69>.
* Build: Build<75>.
* Windows: Windows<65>.
* IDLE: IDLE<53>.
* Tools/Demos: Tools/Demos<40>.

Python 3.6.2 release candidate 2

* Security: Security<49>.

Python 3.6.2 release candidate 1

* Security: Security<50>.
* Core and Builtins: Core and Builtins<151>.
* Library: Library<155>.
* IDLE: IDLE<54>.
* C API: C API<66>.
* Build: Build<76>.
* Documentation: Documentation<69>.
* Tools/Demos: Tools/Demos<41>.
* Tests: Tests<70>.
* Windows: Windows<66>.

Python 3.6.1 final

* Core and Builtins: Core and Builtins<152>.
* Build: Build<77>.

Python 3.6.1 release candidate 1

* Core and Builtins: Core and Builtins<153>.
* Library: Library<156>.
* IDLE: IDLE<55>.
* Windows: Windows<67>.
* C API: C API<67>.
* Documentation: Documentation<70>.
* Tests: Tests<71>.
* Build: Build<78>.

Python 3.6.0 release candidate 2

* Core and Builtins: Core and Builtins<154>.
* Tools/Demos: Tools/Demos<42>.
* Windows: Windows<68>.
* Build: Build<79>.

Python 3.6.0 release candidate 1

* Core and Builtins: Core and Builtins<155>.
* Library: Library<157>.
* C API: C API<68>.
* Documentation: Documentation<71>.
* Tools/Demos: Tools/Demos<43>.

Python 3.6.0 beta 4

* Core and Builtins: Core and Builtins<156>.
* Library: Library<158>.
* Documentation: Documentation<72>.
* Tests: Tests<72>.
* Build: Build<80>.

Python 3.6.0 beta 3

* Core and Builtins: Core and Builtins<157>.
* Library: Library<159>.
* Windows: Windows<69>.
* Build: Build<81>.
* Tests: Tests<73>.

Python 3.6.0 beta 2

* Core and Builtins: Core and Builtins<158>.
* Library: Library<160>.
* Windows: Windows<70>.
* C API: C API<69>.
* Build: Build<82>.
* Tests: Tests<74>.

Python 3.6.0 beta 1

* Core and Builtins: Core and Builtins<159>.
* Library: Library<161>.
* IDLE: IDLE<56>.
* C API: C API<70>.
* Tests: Tests<75>.
* Build: Build<83>.
* Tools/Demos: Tools/Demos<44>.
* Windows: Windows<71>.

Python 3.6.0 alpha 4

* Core and Builtins: Core and Builtins<160>.
* Library: Library<162>.
* IDLE: IDLE<57>.
* Tests: Tests<76>.
* Windows: Windows<72>.
* Build: Build<84>.

Python 3.6.0 alpha 3

* Security: Security<51>.
* Core and Builtins: Core and Builtins<161>.
* Library: Library<163>.
* IDLE: IDLE<58>.
* C API: C API<71>.
* Build: Build<85>.
* Tools/Demos: Tools/Demos<45>.
* Documentation: Documentation<73>.
* Tests: Tests<77>.

Python 3.6.0 alpha 2

* Security: Security<52>.
* Core and Builtins: Core and Builtins<162>.
* Library: Library<164>.
* IDLE: IDLE<59>.
* Documentation: Documentation<74>.
* Tests: Tests<78>.
* Windows: Windows<73>.
* Build: Build<86>.
* C API: C API<72>.
* Tools/Demos: Tools/Demos<46>.

Python 3.6.0 alpha 1

* Security: Security<53>.
* Core and Builtins: Core and Builtins<163>.
* Library: Library<165>.
* IDLE: IDLE<60>.
* Documentation: Documentation<75>.
* Tests: Tests<79>.
* Build: Build<87>.
* Windows: Windows<74>.
* Tools/Demos: Tools/Demos<47>.
* C API: C API<73>.

Python 3.5.5 release candidate 1

* Security: Security<54>.
* Core and Builtins: Core and Builtins<164>.
* Library: Library<166>.

Python 3.5.4 final

* Library: Library<167>.

Python 3.5.4 release candidate 1

* Security: Security<55>.
* Core and Builtins: Core and Builtins<165>.
* Library: Library<168>.
* Documentation: Documentation<76>.
* Tests: Tests<80>.
* Build: Build<88>.
* Windows: Windows<75>.
* C API: C API<74>.

Python 3.5.3 release candidate 1

* Security: Security<56>.
* Core and Builtins: Core and Builtins<166>.
* Library: Library<169>.
* IDLE: IDLE<61>.
* C API: C API<75>.
* Documentation: Documentation<77>.
* Tests: Tests<81>.
* Tools/Demos: Tools/Demos<48>.
* Windows: Windows<76>.
* Build: Build<89>.

Python 3.5.2 final

* Core and Builtins: Core and Builtins<167>.
* Tests: Tests<82>.
* IDLE: IDLE<62>.

Python 3.5.2 release candidate 1

* Security: Security<57>.
* Core and Builtins: Core and Builtins<168>.
* Library: Library<170>.
* IDLE: IDLE<63>.
* Documentation: Documentation<78>.
* Tests: Tests<83>.
* Build: Build<90>.
* Windows: Windows<77>.
* Tools/Demos: Tools/Demos<49>.

Python 3.5.1 final

* Core and Builtins: Core and Builtins<169>.
* Windows: Windows<78>.

Python 3.5.1 release candidate 1

* Core and Builtins: Core and Builtins<170>.
* Library: Library<171>.
* IDLE: IDLE<64>.
* Documentation: Documentation<79>.
* Tests: Tests<84>.
* Build: Build<91>.
* Windows: Windows<79>.
* Tools/Demos: Tools/Demos<50>.

Python 3.5.0 final

* Build: Build<92>.

Python 3.5.0 release candidate 4

* Library: Library<172>.
* Build: Build<93>.

Python 3.5.0 release candidate 3

* Core and Builtins: Core and Builtins<171>.
* Library: Library<173>.

Python 3.5.0 release candidate 2

* Core and Builtins: Core and Builtins<172>.
* Library: Library<174>.

Python 3.5.0 release candidate 1

* Core and Builtins: Core and Builtins<173>.
* Library: Library<175>.
* IDLE: IDLE<65>.
* Documentation: Documentation<80>.
* Tests: Tests<85>.

Python 3.5.0 beta 4

* Core and Builtins: Core and Builtins<174>.
* Library: Library<176>.
* Build: Build<94>.

Python 3.5.0 beta 3

* Core and Builtins: Core and Builtins<175>.
* Library: Library<177>.
* Tests: Tests<86>.
* Documentation: Documentation<81>.
* Build: Build<95>.

Python 3.5.0 beta 2

* Core and Builtins: Core and Builtins<176>.
* Library: Library<178>.

Python 3.5.0 beta 1

* Core and Builtins: Core and Builtins<177>.
* Library: Library<179>.
* IDLE: IDLE<66>.
* Tests: Tests<87>.
* Documentation: Documentation<82>.
* Tools/Demos: Tools/Demos<51>.

Python 3.5.0 alpha 4

* Core and Builtins: Core and Builtins<178>.
* Library: Library<180>.
* Build: Build<96>.
* Tests: Tests<88>.
* Tools/Demos: Tools/Demos<52>.
* C API: C API<76>.

Python 3.5.0 alpha 3

* Core and Builtins: Core and Builtins<179>.
* Library: Library<181>.
* Build: Build<97>.
* Tests: Tests<89>.
* Tools/Demos: Tools/Demos<53>.

Python 3.5.0 alpha 2

* Core and Builtins: Core and Builtins<180>.
* Library: Library<182>.
* Build: Build<98>.
* C API: C API<77>.
* Windows: Windows<80>.

Python 3.5.0 alpha 1

* Core and Builtins: Core and Builtins<181>.
* Library: Library<183>.
* IDLE: IDLE<67>.
* Build: Build<99>.
* C API: C API<78>.
* Documentation: Documentation<83>.
* Tests: Tests<90>.
* Tools/Demos: Tools/Demos<54>.
* Windows: Windows<81>.

The Python Tutorial

* Whetting Your Appetite::
* Using the Python Interpreter::
* An Informal Introduction to Python::
* More Control Flow Tools::
* Data Structures::
* Modules: Modules<2>.
* Input and Output::
* Errors and Exceptions::
* Classes::
* Brief tour of the standard library::
* Brief Tour of the Standard Library — Part II::
* Virtual Environments and Packages::
* What Now?::
* Interactive Input Editing and History Substitution::
* Floating-Point Arithmetic; Issues and Limitations: Floating-Point Arithmetic Issues and Limitations.
* Appendix::

Using the Python Interpreter

* Invoking the Interpreter::
* The Interpreter and Its Environment::

Invoking the Interpreter

* Argument Passing::
* Interactive Mode::

The Interpreter and Its Environment

* Source Code Encoding::

An Informal Introduction to Python

* Using Python as a Calculator::
* First Steps Towards Programming::

Using Python as a Calculator

* Numbers::
* Text::
* Lists::

More Control Flow Tools

* if Statements::
* for Statements::
* The range() Function: The range Function.
* break and continue Statements::
* else Clauses on Loops::
* pass Statements::
* match Statements::
* Defining Functions::
* More on Defining Functions::
* Intermezzo; Coding Style: Intermezzo Coding Style.

More on Defining Functions

* Default Argument Values::
* Keyword Arguments::
* Special parameters::
* Arbitrary Argument Lists::
* Unpacking Argument Lists::
* Lambda Expressions::
* Documentation Strings::
* Function Annotations::

Special parameters

* Positional-or-Keyword Arguments::
* Positional-Only Parameters::
* Keyword-Only Arguments::
* Function Examples::
* Recap::

Data Structures

* More on Lists::
* The del statement::
* Tuples and Sequences::
* Sets::
* Dictionaries::
* Looping Techniques::
* More on Conditions::
* Comparing Sequences and Other Types::

More on Lists

* Using Lists as Stacks::
* Using Lists as Queues::
* List Comprehensions: List Comprehensions<2>.
* Nested List Comprehensions::

Modules

* More on Modules::
* Standard Modules::
* The dir() Function: The dir Function.
* Packages::

More on Modules

* Executing modules as scripts::
* The Module Search Path::
* “Compiled” Python files::

Packages

* Importing * From a Package::
* Intra-package References::
* Packages in Multiple Directories::

Input and Output

* Fancier Output Formatting::
* Reading and Writing Files::

Fancier Output Formatting

* Formatted String Literals::
* The String format() Method: The String format Method.
* Manual String Formatting::
* Old string formatting::

Reading and Writing Files

* Methods of File Objects::
* Saving structured data with json::

Errors and Exceptions

* Syntax Errors::
* Exceptions::
* Handling Exceptions::
* Raising Exceptions::
* Exception Chaining::
* User-defined Exceptions::
* Defining Clean-up Actions::
* Predefined Clean-up Actions::
* Raising and Handling Multiple Unrelated Exceptions::
* Enriching Exceptions with Notes::

Classes

* A Word About Names and Objects::
* Python Scopes and Namespaces::
* A First Look at Classes::
* Random Remarks::
* Inheritance::
* Private Variables::
* Odds and Ends::
* Iterators::
* Generators::
* Generator Expressions::

Python Scopes and Namespaces

* Scopes and Namespaces Example::

A First Look at Classes

* Class Definition Syntax::
* Class Objects::
* Instance Objects::
* Method Objects::
* Class and Instance Variables::

Inheritance

* Multiple Inheritance::

Brief tour of the standard library

* Operating system interface::
* File wildcards::
* Command-line arguments::
* Error output redirection and program termination::
* String pattern matching::
* Mathematics::
* Internet access::
* Dates and times::
* Data compression::
* Performance measurement::
* Quality control::
* Batteries included::

Brief Tour of the Standard Library — Part II

* Output Formatting::
* Templating::
* Working with Binary Data Record Layouts::
* Multi-threading: Multi-threading<2>.
* Logging::
* Weak References::
* Tools for Working with Lists::
* Decimal Floating-Point Arithmetic::

Virtual Environments and Packages

* Introduction: Introduction<4>.
* Creating Virtual Environments::
* Managing Packages with pip::

Interactive Input Editing and History Substitution

* Tab Completion and History Editing::
* Alternatives to the Interactive Interpreter::

Floating-Point Arithmetic:  Issues and Limitations

* Representation Error::

Appendix

* Interactive Mode: Interactive Mode<2>.

Interactive Mode

* Error Handling::
* Executable Python Scripts::
* The Interactive Startup File::
* The Customization Modules::

Python Setup and Usage

* Command line and environment::
* Using Python on Unix platforms::
* Configure Python::
* Using Python on Windows::
* Using Python on macOS::
* Using Python on Android::
* Using Python on iOS::
* Editors and IDEs::

Command line and environment

* Command line::
* Environment variables::

Command line

* Interface options::
* Generic options::
* Miscellaneous options::
* Controlling color::
* Options you shouldn’t use::

Environment variables

* Debug-mode variables::

Using Python on Unix platforms

* Getting and installing the latest version of Python::
* Building Python::
* Python-related paths and files::
* Miscellaneous::
* Custom OpenSSL::

Getting and installing the latest version of Python

* On Linux::
* On FreeBSD and OpenBSD::

On Linux

* Installing IDLE::

Configure Python

* Build Requirements::
* Generated files::
* Configure Options::
* Python Build System::
* Compiler and linker flags::

Generated files

* configure script::

Configure Options

* General Options::
* C compiler options::
* Linker options::
* Options for third-party dependencies::
* WebAssembly Options::
* Install Options::
* Performance options::
* Python Debug Build::
* Debug options::
* Linker options: Linker options<2>.
* Libraries options::
* Security Options::
* macOS Options::
* iOS Options::
* Cross Compiling Options::

Python Build System

* Main files of the build system::
* Main build steps::
* Main Makefile targets::
* C extensions::

Main Makefile targets

* make::
* make platform::
* make profile-opt::
* make clean::
* make distclean::
* make install::
* make test::
* make buildbottest::
* make regen-all::

Compiler and linker flags

* Preprocessor flags::
* Compiler flags::
* Linker flags::

Using Python on Windows

* The full installer::
* The Microsoft Store package::
* The nuget.org packages: The nuget org packages.
* The embeddable package::
* Alternative bundles::
* Configuring Python::
* UTF-8 mode::
* Python Launcher for Windows::
* Finding modules::
* Additional modules::
* Compiling Python on Windows::
* Other Platforms::

The full installer

* Installation steps::
* Removing the MAX_PATH Limitation::
* Installing Without UI::
* Installing Without Downloading::
* Modifying an install::
* Installing Free-threaded Binaries::

The Microsoft Store package

* Known issues::

Known issues

* Redirection of local data, registry, and temporary paths: Redirection of local data registry and temporary paths.

The nuget.org packages

* Free-threaded packages::

The embeddable package

* Python Application::
* Embedding Python::

Configuring Python

* Excursus; Setting environment variables: Excursus Setting environment variables.
* Finding the Python executable::

Python Launcher for Windows

* Getting started::
* Shebang Lines::
* Arguments in shebang lines::
* Customization::
* Diagnostics::
* Dry Run::
* Install on demand::
* Return codes::

Getting started

* From the command-line::
* Virtual environments::
* From a script::
* From file associations::

Customization

* Customization via INI files::
* Customizing default Python versions::

Additional modules

* PyWin32::
* cx_Freeze::

Using Python on macOS

* Using Python for macOS from python.org: Using Python for macOS from python org.
* Alternative Distributions::
* Installing Additional Python Packages::
* GUI Programming::
* Advanced Topics::
* Other Resources::

Using Python for macOS from python.org

* Installation steps: Installation steps<2>.
* How to run a Python script::

Advanced Topics

* Installing Free-threaded Binaries: Installing Free-threaded Binaries<2>.
* Installing using the command line::
* Distributing Python Applications::
* App Store Compliance::

Using Python on Android

* Adding Python to an Android app::
* Building a Python package for Android::

Using Python on iOS

* Python at runtime on iOS::
* Installing Python on iOS::
* App Store Compliance: App Store Compliance<2>.

Python at runtime on iOS

* iOS version compatibility::
* Platform identification::
* Standard library availability::
* Binary extension modules::
* Compiler stub binaries::

Installing Python on iOS

* Tools for building iOS apps::
* Adding Python to an iOS project::
* Testing a Python package::

Editors and IDEs

* IDLE — Python editor and shell::
* Other Editors and IDEs::

The Python Language Reference

* Introduction: Introduction<5>.
* Lexical analysis::
* Data model::
* Execution model::
* The import system::
* Expressions::
* Simple statements::
* Compound statements::
* Top-level components::
* Full Grammar specification::

Introduction

* Alternate Implementations::
* Notation::

Lexical analysis

* Line structure::
* Other tokens::
* Identifiers and keywords::
* Literals::
* Operators::
* Delimiters::

Line structure

* Logical lines::
* Physical lines::
* Comments::
* Encoding declarations::
* Explicit line joining::
* Implicit line joining::
* Blank lines::
* Indentation::
* Whitespace between tokens::

Identifiers and keywords

* Keywords::
* Soft Keywords::
* Reserved classes of identifiers::

Literals

* String and Bytes literals::
* String literal concatenation::
* f-strings::
* Numeric literals::
* Integer literals::
* Floating-point literals::
* Imaginary literals::

String and Bytes literals

* Escape sequences::

Data model

* Objects, values and types: Objects values and types.
* The standard type hierarchy::
* Special method names::
* Coroutines::

The standard type hierarchy

* None::
* NotImplemented::
* Ellipsis::
* numbers.Number: numbers Number.
* Sequences::
* Set types::
* Mappings::
* Callable types::
* Modules: Modules<3>.
* Custom classes::
* Class instances::
* I/O objects (also known as file objects): I/O objects also known as file objects.
* Internal types::

numbers.Number

* numbers.Integral: numbers Integral.
* numbers.Real (float): numbers Real float.
* numbers.Complex (complex): numbers Complex complex.

Sequences

* Immutable sequences::
* Mutable sequences::

Mappings

* Dictionaries: Dictionaries<2>.

Callable types

* User-defined functions::
* Instance methods::
* Generator functions::
* Coroutine functions::
* Asynchronous generator functions::
* Built-in functions::
* Built-in methods::
* Classes: Classes<2>.
* Class Instances::

User-defined functions

* Special read-only attributes::
* Special writable attributes::

Modules

* Import-related attributes on module objects::
* Other writable attributes on module objects::
* Module dictionaries::

Custom classes

* Special attributes::
* Special methods::

Class instances

* Special attributes: Special attributes<2>.

Internal types

* Code objects::
* Frame objects::
* Traceback objects::
* Slice objects::
* Static method objects::
* Class method objects::

Code objects

* Special read-only attributes: Special read-only attributes<2>.
* Methods on code objects::

Frame objects

* Special read-only attributes: Special read-only attributes<3>.
* Special writable attributes: Special writable attributes<2>.
* Frame object methods::

Special method names

* Basic customization::
* Customizing attribute access::
* Customizing class creation::
* Customizing instance and subclass checks::
* Emulating generic types::
* Emulating callable objects::
* Emulating container types::
* Emulating numeric types::
* With Statement Context Managers::
* Customizing positional arguments in class pattern matching::
* Emulating buffer types::
* Special method lookup::

Customizing attribute access

* Customizing module attribute access::
* Implementing Descriptors::
* Invoking Descriptors::
* __slots__: __slots__<2>.

Customizing class creation

* Metaclasses::
* Resolving MRO entries::
* Determining the appropriate metaclass::
* Preparing the class namespace::
* Executing the class body::
* Creating the class object::
* Uses for metaclasses::

Emulating generic types

* The purpose of __class_getitem__::
* __class_getitem__ versus __getitem__::

Coroutines

* Awaitable Objects::
* Coroutine Objects::
* Asynchronous Iterators::
* Asynchronous Context Managers::

Execution model

* Structure of a program::
* Naming and binding::
* Exceptions: Exceptions<2>.

Naming and binding

* Binding of names::
* Resolution of names::
* Annotation scopes::
* Lazy evaluation::
* Builtins and restricted execution::
* Interaction with dynamic features::

The import system

* importlib: importlib<10>.
* Packages: Packages<2>.
* Searching::
* Loading::
* The Path Based Finder::
* Replacing the standard import system::
* Package Relative Imports::
* Special considerations for __main__::
* References::

Packages

* Regular packages::
* Namespace packages::

Searching

* The module cache::
* Finders and loaders::
* Import hooks::
* The meta path::

Loading

* Loaders::
* Submodules::
* Module specs::
* __path__ attributes on modules::
* Module reprs::
* Cached bytecode invalidation::

The Path Based Finder

* Path entry finders::
* Path entry finder protocol::

Special considerations for __main__

* __main__.__spec__: __main__ __spec__.

Expressions

* Arithmetic conversions::
* Atoms::
* Primaries::
* Await expression::
* The power operator::
* Unary arithmetic and bitwise operations::
* Binary arithmetic operations::
* Shifting operations::
* Binary bitwise operations::
* Comparisons::
* Boolean operations::
* Assignment expressions: Assignment expressions<2>.
* Conditional expressions::
* Lambdas::
* Expression lists::
* Evaluation order::
* Operator precedence::

Atoms

* Identifiers (Names): Identifiers Names.
* Literals: Literals<2>.
* Parenthesized forms::
* Displays for lists, sets and dictionaries: Displays for lists sets and dictionaries.
* List displays::
* Set displays::
* Dictionary displays::
* Generator expressions::
* Yield expressions::

Identifiers (Names)

* Private name mangling::

Yield expressions

* Generator-iterator methods::
* Examples::
* Asynchronous generator functions: Asynchronous generator functions<2>.
* Asynchronous generator-iterator methods::

Primaries

* Attribute references::
* Subscriptions::
* Slicings::
* Calls::

Comparisons

* Value comparisons::
* Membership test operations::
* Identity comparisons::

Simple statements

* Expression statements::
* Assignment statements::
* The assert statement::
* The pass statement::
* The del statement: The del statement<2>.
* The return statement::
* The yield statement::
* The raise statement::
* The break statement::
* The continue statement::
* The import statement::
* The global statement::
* The nonlocal statement::
* The type statement::

Assignment statements

* Augmented assignment statements::
* Annotated assignment statements::

The import statement

* Future statements::

Compound statements

* The if statement::
* The while statement::
* The for statement::
* The try statement::
* The with statement::
* The match statement::
* Function definitions::
* Class definitions::
* Coroutines: Coroutines<2>.
* Type parameter lists::

The try statement

* except clause::
* except* clause::
* else clause::
* finally clause::

The match statement

* Overview::
* Guards::
* Irrefutable Case Blocks::
* Patterns::

Patterns

* OR Patterns::
* AS Patterns::
* Literal Patterns::
* Capture Patterns::
* Wildcard Patterns::
* Value Patterns::
* Group Patterns::
* Sequence Patterns::
* Mapping Patterns::
* Class Patterns::

Coroutines

* Coroutine function definition::
* The async for statement::
* The async with statement::

Type parameter lists

* Generic functions::
* Generic classes::
* Generic type aliases::

Top-level components

* Complete Python programs::
* File input::
* Interactive input::
* Expression input::

The Python Standard Library

* Introduction: Introduction<6>.
* Built-in Functions::
* Built-in Constants::
* Built-in Types::
* Built-in Exceptions::
* Text Processing Services::
* Binary Data Services::
* Data Types::
* Numeric and Mathematical Modules::
* Functional Programming Modules::
* File and Directory Access::
* Data Persistence::
* Data Compression and Archiving::
* File Formats::
* Cryptographic Services::
* Generic Operating System Services::
* Command-line interface libraries::
* Concurrent Execution::
* Networking and Interprocess Communication::
* Internet Data Handling::
* Structured Markup Processing Tools::
* Internet Protocols and Support::
* Multimedia Services::
* Internationalization::
* Graphical user interfaces with Tk::
* Development Tools::
* Debugging and Profiling::
* Software Packaging and Distribution::
* Python Runtime Services::
* Custom Python Interpreters::
* Importing Modules::
* Python Language Services::
* MS Windows Specific Services::
* Unix-specific services::
* Modules command-line interface (CLI): Modules command-line interface CLI.
* Superseded Modules::
* Removed Modules::
* Security Considerations: Security Considerations<3>.

Introduction

* Notes on availability::

Notes on availability

* WebAssembly platforms::
* Mobile platforms::

Built-in Constants

* Constants added by the site module::

Built-in Types

* Truth Value Testing::
* Boolean Operations — and, or, not: Boolean Operations — and or not.
* Comparisons: Comparisons<2>.
* Numeric Types — int, float, complex: Numeric Types — int float complex.
* Boolean Type - bool::
* Iterator Types::
* Sequence Types — list, tuple, range: Sequence Types — list tuple range.
* Text Sequence Type — str::
* Binary Sequence Types — bytes, bytearray, memoryview: Binary Sequence Types — bytes bytearray memoryview.
* Set Types — set, frozenset: Set Types — set frozenset.
* Mapping Types — dict::
* Context Manager Types::
* Type Annotation Types — Generic Alias, Union: Type Annotation Types — Generic Alias Union.
* Other Built-in Types::
* Special Attributes::
* Integer string conversion length limitation::

Numeric Types — int, float, complex

* Bitwise Operations on Integer Types::
* Additional Methods on Integer Types::
* Additional Methods on Float::
* Hashing of numeric types::

Iterator Types

* Generator Types::

Sequence Types — list, tuple, range

* Common Sequence Operations::
* Immutable Sequence Types::
* Mutable Sequence Types::
* Lists: Lists<2>.
* Tuples::
* Ranges::

Text Sequence Type — str

* String Methods: String Methods<2>.
* Formatted String Literals (f-strings): Formatted String Literals f-strings.
* printf-style String Formatting::

Binary Sequence Types — bytes, bytearray, memoryview

* Bytes Objects::
* Bytearray Objects::
* Bytes and Bytearray Operations::
* printf-style Bytes Formatting::
* Memory Views::

Mapping Types — dict

* Dictionary view objects::

Type Annotation Types — Generic Alias, Union

* Generic Alias Type::
* Union Type::

Generic Alias Type

* Standard Generic Classes::
* Special Attributes of GenericAlias objects::

Other Built-in Types

* Modules: Modules<4>.
* Classes and Class Instances::
* Functions::
* Methods::
* Code Objects::
* Type Objects::
* The Null Object::
* The Ellipsis Object::
* The NotImplemented Object::
* Internal Objects::

Integer string conversion length limitation

* Affected APIs::
* Configuring the limit::
* Recommended configuration::

Built-in Exceptions

* Exception context::
* Inheriting from built-in exceptions::
* Base classes::
* Concrete exceptions::
* Warnings::
* Exception groups::
* Exception hierarchy::

Concrete exceptions

* OS exceptions::

Text Processing Services

* string — Common string operations::
* re — Regular expression operations::
* difflib — Helpers for computing deltas::
* textwrap — Text wrapping and filling::
* unicodedata — Unicode Database::
* stringprep — Internet String Preparation::
* readline — GNU readline interface::
* rlcompleter — Completion function for GNU readline::

string — Common string operations

* String constants::
* Custom string formatting::
* Format string syntax::
* Template strings::
* Helper functions::

Format string syntax

* Format specification mini-language::
* Format examples::

re — Regular expression operations

* Regular Expression Syntax::
* Module Contents::
* Regular Expression Objects::
* Match Objects::
* Regular Expression Examples::

Module Contents

* Flags::
* Functions: Functions<2>.
* Exceptions: Exceptions<3>.

Regular Expression Examples

* Checking for a Pair::
* Simulating scanf(): Simulating scanf.
* search() vs. match(): search vs match.
* Making a Phonebook::
* Text Munging::
* Finding all Adverbs::
* Finding all Adverbs and their Positions::
* Raw String Notation::
* Writing a Tokenizer::

difflib — Helpers for computing deltas

* SequenceMatcher objects::
* SequenceMatcher examples::
* Differ objects::
* Differ example::
* A command-line interface to difflib::
* ndiff example::

readline — GNU readline interface

* Init file::
* Line buffer::
* History file::
* History list::
* Startup hooks::
* Completion::
* Example::

Binary Data Services

* struct — Interpret bytes as packed binary data::
* codecs — Codec registry and base classes::

struct — Interpret bytes as packed binary data

* Functions and Exceptions::
* Format Strings::
* Applications::
* Classes: Classes<3>.

Format Strings

* Byte Order, Size, and Alignment: Byte Order Size and Alignment.
* Format Characters::
* Examples: Examples<2>.

Applications

* Native Formats::
* Standard Formats::

codecs — Codec registry and base classes

* Codec Base Classes::
* Encodings and Unicode::
* Standard Encodings::
* Python Specific Encodings::
* encodings — Encodings package::
* encodings.idna — Internationalized Domain Names in Applications: encodings idna — Internationalized Domain Names in Applications.
* encodings.mbcs — Windows ANSI codepage: encodings mbcs — Windows ANSI codepage.
* encodings.utf_8_sig — UTF-8 codec with BOM signature: encodings utf_8_sig — UTF-8 codec with BOM signature.

Codec Base Classes

* Error Handlers::
* Stateless Encoding and Decoding::
* Incremental Encoding and Decoding::
* Stream Encoding and Decoding::

Incremental Encoding and Decoding

* IncrementalEncoder Objects::
* IncrementalDecoder Objects::

Stream Encoding and Decoding

* StreamWriter Objects::
* StreamReader Objects::
* StreamReaderWriter Objects::
* StreamRecoder Objects::

Python Specific Encodings

* Text Encodings::
* Binary Transforms::
* Standalone Codec Functions::
* Text Transforms::

Data Types

* datetime — Basic date and time types::
* zoneinfo — IANA time zone support::
* calendar — General calendar-related functions::
* collections — Container datatypes::
* collections.abc — Abstract Base Classes for Containers: collections abc — Abstract Base Classes for Containers.
* heapq — Heap queue algorithm::
* bisect — Array bisection algorithm::
* array — Efficient arrays of numeric values::
* weakref — Weak references::
* types — Dynamic type creation and names for built-in types::
* copy — Shallow and deep copy operations::
* pprint — Data pretty printer::
* reprlib — Alternate repr() implementation: reprlib — Alternate repr implementation.
* enum — Support for enumerations::
* graphlib — Functionality to operate with graph-like structures::

datetime — Basic date and time types

* Aware and Naive Objects::
* Constants::
* Available Types::
* timedelta Objects::
* date Objects::
* datetime Objects::
* time Objects::
* tzinfo Objects::
* timezone Objects::
* strftime() and strptime() Behavior: strftime and strptime Behavior.

Available Types

* Common Properties::
* Determining if an Object is Aware or Naive::

timedelta Objects

* Examples of usage; timedelta: Examples of usage timedelta.

date Objects

* Examples of Usage; date: Examples of Usage date.

datetime Objects

* Examples of Usage; datetime: Examples of Usage datetime.

time Objects

* Examples of Usage; time: Examples of Usage time.

strftime() and strptime() Behavior

* strftime() and strptime() Format Codes: strftime and strptime Format Codes.
* Technical Detail::

zoneinfo — IANA time zone support

* Using ZoneInfo::
* Data sources::
* The ZoneInfo class::
* Functions: Functions<3>.
* Globals::
* Exceptions and warnings::

Data sources

* Configuring the data sources::

Configuring the data sources

* Compile-time configuration::
* Environment configuration::
* Runtime configuration::

The ZoneInfo class

* String representations::
* Pickle serialization::

calendar — General calendar-related functions

* Command-Line Usage::

collections — Container datatypes

* ChainMap objects::
* Counter objects::
* deque objects::
* defaultdict objects::
* namedtuple() Factory Function for Tuples with Named Fields: namedtuple Factory Function for Tuples with Named Fields.
* OrderedDict objects::
* UserDict objects::
* UserList objects::
* UserString objects::

ChainMap objects

* ChainMap Examples and Recipes::

deque objects

* deque Recipes::

defaultdict objects

* defaultdict Examples::

OrderedDict objects

* OrderedDict Examples and Recipes::

collections.abc — Abstract Base Classes for Containers

* Collections Abstract Base Classes::
* Collections Abstract Base Classes – Detailed Descriptions::
* Examples and Recipes::

heapq — Heap queue algorithm

* Basic Examples::
* Priority Queue Implementation Notes::
* Theory::

bisect — Array bisection algorithm

* Performance Notes::
* Searching Sorted Lists::
* Examples: Examples<3>.

weakref — Weak references

* Weak Reference Objects::
* Example: Example<2>.
* Finalizer Objects::
* Comparing finalizers with __del__() methods: Comparing finalizers with __del__ methods.

types — Dynamic type creation and names for built-in types

* Dynamic Type Creation::
* Standard Interpreter Types::
* Additional Utility Classes and Functions::
* Coroutine Utility Functions::

pprint — Data pretty printer

* Functions: Functions<4>.
* PrettyPrinter Objects::
* Example: Example<3>.

reprlib — Alternate repr() implementation

* Repr Objects::
* Subclassing Repr Objects::

enum — Support for enumerations

* Module contents::
* Data types::
* Utilities and decorators::
* Notes::

Data types

* Supported __dunder__ names::
* Supported _sunder_ names::

graphlib — Functionality to operate with graph-like structures

* Exceptions: Exceptions<4>.

Numeric and Mathematical Modules

* numbers — Numeric abstract base classes::
* math — Mathematical functions::
* cmath — Mathematical functions for complex numbers::
* decimal — Decimal fixed-point and floating-point arithmetic::
* fractions — Rational numbers::
* random — Generate pseudo-random numbers::
* statistics — Mathematical statistics functions::

numbers — Numeric abstract base classes

* The numeric tower::
* Notes for type implementers::

Notes for type implementers

* Adding More Numeric ABCs::
* Implementing the arithmetic operations::

math — Mathematical functions

* Number-theoretic functions::
* Floating point arithmetic::
* Floating point manipulation functions::
* Power, exponential and logarithmic functions: Power exponential and logarithmic functions.
* Summation and product functions::
* Angular conversion::
* Trigonometric functions::
* Hyperbolic functions::
* Special functions::
* Constants: Constants<2>.

cmath — Mathematical functions for complex numbers

* Conversions to and from polar coordinates::
* Power and logarithmic functions::
* Trigonometric functions: Trigonometric functions<2>.
* Hyperbolic functions: Hyperbolic functions<2>.
* Classification functions::
* Constants: Constants<3>.

decimal — Decimal fixed-point and floating-point arithmetic

* Quick-start tutorial::
* Decimal objects::
* Context objects::
* Constants: Constants<4>.
* Rounding modes::
* Signals::
* Floating-point notes::
* Working with threads::
* Recipes::
* Decimal FAQ::

Decimal objects

* Logical operands::

Floating-point notes

* Mitigating round-off error with increased precision::
* Special values::

random — Generate pseudo-random numbers

* Bookkeeping functions::
* Functions for bytes::
* Functions for integers::
* Functions for sequences::
* Discrete distributions::
* Real-valued distributions::
* Alternative Generator::
* Notes on Reproducibility::
* Examples: Examples<4>.
* Recipes: Recipes<2>.
* Command-line usage::
* Command-line example::

statistics — Mathematical statistics functions

* Averages and measures of central location::
* Measures of spread::
* Statistics for relations between two inputs::
* Function details::
* Exceptions: Exceptions<5>.
* NormalDist objects::
* Examples and Recipes: Examples and Recipes<2>.

Examples and Recipes

* Classic probability problems::
* Monte Carlo inputs for simulations::
* Approximating binomial distributions::
* Naive bayesian classifier::

Functional Programming Modules

* itertools — Functions creating iterators for efficient looping::
* functools — Higher-order functions and operations on callable objects::
* operator — Standard operators as functions::

itertools — Functions creating iterators for efficient looping

* Itertool Functions::
* Itertools Recipes::

functools — Higher-order functions and operations on callable objects

* partial Objects::

operator — Standard operators as functions

* Mapping Operators to Functions::
* In-place Operators::

File and Directory Access

* pathlib — Object-oriented filesystem paths::
* os.path — Common pathname manipulations: os path — Common pathname manipulations.
* stat — Interpreting stat() results: stat — Interpreting stat results.
* filecmp — File and Directory Comparisons::
* tempfile — Generate temporary files and directories::
* glob — Unix style pathname pattern expansion::
* fnmatch — Unix filename pattern matching::
* linecache — Random access to text lines::
* shutil — High-level file operations::

pathlib — Object-oriented filesystem paths

* Basic use::
* Exceptions: Exceptions<6>.
* Pure paths::
* Concrete paths::
* Pattern language::
* Comparison to the glob module::
* Comparison to the os and os.path modules: Comparison to the os and os path modules.

Pure paths

* General properties::
* Operators: Operators<2>.
* Accessing individual parts::
* Methods and properties::

Concrete paths

* Parsing and generating URIs::
* Expanding and resolving paths::
* Querying file type and status::
* Reading and writing files::
* Reading directories::
* Creating files and directories::
* Renaming and deleting::
* Permissions and ownership::

Comparison to the os and os.path modules

* Corresponding tools::

filecmp — File and Directory Comparisons

* The dircmp class::

tempfile — Generate temporary files and directories

* Examples: Examples<5>.
* Deprecated functions and variables::

glob — Unix style pathname pattern expansion

* Examples: Examples<6>.

shutil — High-level file operations

* Directory and files operations::
* Archiving operations::
* Querying the size of the output terminal::

Directory and files operations

* Platform-dependent efficient copy operations::
* copytree example::
* rmtree example::

Archiving operations

* Archiving example::
* Archiving example with base_dir::

Data Persistence

* pickle — Python object serialization::
* copyreg — Register pickle support functions::
* shelve — Python object persistence::
* marshal — Internal Python object serialization::
* dbm — Interfaces to Unix “databases”::
* sqlite3 — DB-API 2.0 interface for SQLite databases: sqlite3 — DB-API 2 0 interface for SQLite databases.

pickle — Python object serialization

* Relationship to other Python modules::
* Data stream format::
* Module Interface::
* What can be pickled and unpickled?::
* Pickling Class Instances::
* Custom Reduction for Types, Functions, and Other Objects: Custom Reduction for Types Functions and Other Objects.
* Out-of-band Buffers::
* Restricting Globals::
* Performance: Performance<2>.
* Examples: Examples<7>.

Relationship to other Python modules

* Comparison with marshal::
* Comparison with json::

Pickling Class Instances

* Persistence of External Objects::
* Dispatch Tables::
* Handling Stateful Objects::

Out-of-band Buffers

* Provider API::
* Consumer API::
* Example: Example<4>.

copyreg — Register pickle support functions

* Example: Example<5>.

shelve — Python object persistence

* Restrictions::
* Example: Example<6>.

dbm — Interfaces to Unix “databases”

* dbm.sqlite3 — SQLite backend for dbm: dbm sqlite3 — SQLite backend for dbm.
* dbm.gnu — GNU database manager: dbm gnu — GNU database manager.
* dbm.ndbm — New Database Manager: dbm ndbm — New Database Manager.
* dbm.dumb — Portable DBM implementation: dbm dumb — Portable DBM implementation.

sqlite3 — DB-API 2.0 interface for SQLite databases

* Tutorial::
* Reference::
* How-to guides::
* Explanation::

Reference

* Module functions::
* Module constants::
* Connection objects::
* Cursor objects::
* Row objects::
* Blob objects::
* PrepareProtocol objects::
* Exceptions: Exceptions<7>.
* SQLite and Python types::
* Default adapters and converters (deprecated): Default adapters and converters deprecated.
* Command-line interface::

How-to guides

* How to use placeholders to bind values in SQL queries::
* How to adapt custom Python types to SQLite values::
* How to convert SQLite values to custom Python types::
* Adapter and converter recipes::
* How to use connection shortcut methods::
* How to use the connection context manager::
* How to work with SQLite URIs::
* How to create and use row factories::
* How to handle non-UTF-8 text encodings::

How to adapt custom Python types to SQLite values

* How to write adaptable objects::
* How to register adapter callables::

Explanation

* Transaction control::

Transaction control

* Transaction control via the autocommit attribute::
* Transaction control via the isolation_level attribute::

Data Compression and Archiving

* zlib — Compression compatible with gzip::
* gzip — Support for gzip files::
* bz2 — Support for bzip2 compression::
* lzma — Compression using the LZMA algorithm::
* zipfile — Work with ZIP archives::
* tarfile — Read and write tar archive files::

gzip — Support for gzip files

* Examples of usage::
* Command-line interface: Command-line interface<2>.

Command-line interface

* Command-line options::

bz2 — Support for bzip2 compression

* (De)compression of files: De compression of files.
* Incremental (de)compression: Incremental de compression.
* One-shot (de)compression: One-shot de compression.
* Examples of usage: Examples of usage<2>.

lzma — Compression using the LZMA algorithm

* Reading and writing compressed files::
* Compressing and decompressing data in memory::
* Miscellaneous: Miscellaneous<2>.
* Specifying custom filter chains::
* Examples: Examples<8>.

zipfile — Work with ZIP archives

* ZipFile objects::
* Path objects::
* PyZipFile objects::
* ZipInfo objects::
* Command-line interface: Command-line interface<3>.
* Decompression pitfalls::

Command-line interface

* Command-line options: Command-line options<2>.

Decompression pitfalls

* From file itself::
* File system limitations::
* Resources limitations::
* Interruption::
* Default behaviors of extraction::

tarfile — Read and write tar archive files

* TarFile Objects::
* TarInfo Objects::
* Extraction filters::
* Command-Line Interface::
* Examples: Examples<9>.
* Supported tar formats::
* Unicode issues::

Extraction filters

* Default named filters::
* Filter errors::
* Hints for further verification::
* Supporting older Python versions::
* Stateful extraction filter example::

Command-Line Interface

* Command-line options: Command-line options<3>.

Examples

* Reading examples::
* Writing examples::

File Formats

* csv — CSV File Reading and Writing::
* configparser — Configuration file parser::
* tomllib — Parse TOML files::
* netrc — netrc file processing::
* plistlib — Generate and parse Apple .plist files: plistlib — Generate and parse Apple plist files.

csv — CSV File Reading and Writing

* Module Contents: Module Contents<2>.
* Dialects and Formatting Parameters::
* Reader Objects::
* Writer Objects::
* Examples: Examples<10>.

configparser — Configuration file parser

* Quick Start::
* Supported Datatypes::
* Fallback Values::
* Supported INI File Structure::
* Unnamed Sections::
* Interpolation of values::
* Mapping Protocol Access::
* Customizing Parser Behaviour::
* Legacy API Examples::
* ConfigParser Objects::
* RawConfigParser Objects::
* Exceptions: Exceptions<8>.

tomllib — Parse TOML files

* Examples: Examples<11>.
* Conversion Table::

netrc — netrc file processing

* netrc Objects::

plistlib — Generate and parse Apple .plist files

* Examples: Examples<12>.

Cryptographic Services

* hashlib — Secure hashes and message digests::
* hmac — Keyed-Hashing for Message Authentication::
* secrets — Generate secure random numbers for managing secrets::

hashlib — Secure hashes and message digests

* Hash algorithms::
* Usage::
* Constructors::
* Attributes::
* Hash Objects::
* SHAKE variable length digests::
* File hashing::
* Key derivation::
* BLAKE2::

BLAKE2

* Creating hash objects::
* Constants: Constants<5>.
* Examples: Examples<13>.
* Credits::

Examples

* Simple hashing::
* Using different digest sizes::
* Keyed hashing::
* Randomized hashing::
* Personalization::
* Tree mode::

secrets — Generate secure random numbers for managing secrets

* Random numbers::
* Generating tokens::
* Other functions::
* Recipes and best practices::

Generating tokens

* How many bytes should tokens use?::

Generic Operating System Services

* os — Miscellaneous operating system interfaces::
* io — Core tools for working with streams::
* time — Time access and conversions::
* logging — Logging facility for Python::
* logging.config — Logging configuration: logging config — Logging configuration.
* logging.handlers — Logging handlers: logging handlers — Logging handlers.
* platform — Access to underlying platform’s identifying data::
* errno — Standard errno system symbols::
* ctypes — A foreign function library for Python::

os — Miscellaneous operating system interfaces

* File Names, Command Line Arguments, and Environment Variables: File Names Command Line Arguments and Environment Variables.
* Python UTF-8 Mode::
* Process Parameters::
* File Object Creation::
* File Descriptor Operations::
* Files and Directories::
* Process Management::
* Interface to the scheduler::
* Miscellaneous System Information::
* Random numbers: Random numbers<2>.

File Descriptor Operations

* Querying the size of a terminal::
* Inheritance of File Descriptors::

Files and Directories

* Timer File Descriptors::
* Linux extended attributes::

io — Core tools for working with streams

* Overview: Overview<2>.
* Text Encoding::
* High-level Module Interface::
* Class hierarchy::
* Performance: Performance<3>.

Overview

* Text I/O::
* Binary I/O::
* Raw I/O::

Text Encoding

* Opt-in EncodingWarning::

Class hierarchy

* I/O Base Classes::
* Raw File I/O::
* Buffered Streams::
* Text I/O: Text I/O<2>.

Performance

* Binary I/O: Binary I/O<2>.
* Text I/O: Text I/O<3>.
* Multi-threading: Multi-threading<3>.
* Reentrancy::

time — Time access and conversions

* Functions: Functions<5>.
* Clock ID Constants::
* Timezone Constants::

logging — Logging facility for Python

* Logger Objects::
* Logging Levels::
* Handler Objects::
* Formatter Objects::
* Filter Objects::
* LogRecord Objects::
* LogRecord attributes::
* LoggerAdapter Objects::
* Thread Safety::
* Module-Level Functions::
* Module-Level Attributes::
* Integration with the warnings module::

logging.config — Logging configuration

* Configuration functions::
* Security considerations::
* Configuration dictionary schema::
* Configuration file format::

Configuration dictionary schema

* Dictionary Schema Details::
* Incremental Configuration::
* Object connections::
* User-defined objects::
* Handler configuration order::
* Access to external objects::
* Access to internal objects::
* Import resolution and custom importers::
* Configuring QueueHandler and QueueListener::

logging.handlers — Logging handlers

* StreamHandler::
* FileHandler::
* NullHandler::
* WatchedFileHandler::
* BaseRotatingHandler::
* RotatingFileHandler::
* TimedRotatingFileHandler::
* SocketHandler::
* DatagramHandler::
* SysLogHandler::
* NTEventLogHandler::
* SMTPHandler::
* MemoryHandler::
* HTTPHandler::
* QueueHandler::
* QueueListener::

platform —  Access to underlying platform’s identifying data

* Cross platform::
* Java platform::
* Windows platform::
* macOS platform::
* iOS platform::
* Unix platforms::
* Linux platforms::
* Android platform::
* Command-line usage: Command-line usage<2>.

ctypes — A foreign function library for Python

* ctypes tutorial::
* ctypes reference::

ctypes tutorial

* Loading dynamic link libraries::
* Accessing functions from loaded dlls::
* Calling functions::
* Fundamental data types::
* Calling functions, continued: Calling functions continued.
* Calling variadic functions::
* Calling functions with your own custom data types::
* Specifying the required argument types (function prototypes): Specifying the required argument types function prototypes.
* Return types::
* Passing pointers (or; passing parameters by reference): Passing pointers or passing parameters by reference.
* Structures and unions::
* Structure/union alignment and byte order::
* Bit fields in structures and unions::
* Arrays::
* Pointers::
* Type conversions::
* Incomplete Types::
* Callback functions::
* Accessing values exported from dlls::
* Surprises::
* Variable-sized data types::

ctypes reference

* Finding shared libraries::
* Loading shared libraries::
* Foreign functions::
* Function prototypes::
* Utility functions::
* Data types: Data types<2>.
* Fundamental data types: Fundamental data types<2>.
* Structured data types::
* Arrays and pointers::

Command-line interface libraries

* argparse — Parser for command-line options, arguments and subcommands: argparse — Parser for command-line options arguments and subcommands.
* optparse — Parser for command line options::
* getpass — Portable password input::
* fileinput — Iterate over lines from multiple input streams::
* curses — Terminal handling for character-cell displays::
* curses.textpad — Text input widget for curses programs: curses textpad — Text input widget for curses programs.
* curses.ascii — Utilities for ASCII characters: curses ascii — Utilities for ASCII characters.
* curses.panel — A panel stack extension for curses: curses panel — A panel stack extension for curses.
* cmd — Support for line-oriented command interpreters::

argparse — Parser for command-line options, arguments and subcommands

* ArgumentParser objects::
* The add_argument() method: The add_argument method.
* The parse_args() method: The parse_args method.
* Other utilities::
* Exceptions: Exceptions<9>.

ArgumentParser objects

* prog::
* usage::
* description::
* epilog::
* parents::
* formatter_class::
* prefix_chars::
* fromfile_prefix_chars::
* argument_default::
* allow_abbrev::
* conflict_handler::
* add_help::
* exit_on_error::

The add_argument() method

* name or flags::
* action::
* nargs::
* const::
* default::
* type::
* choices::
* required::
* help::
* metavar::
* dest::
* deprecated::
* Action classes::

The parse_args() method

* Option value syntax::
* Invalid arguments::
* Arguments containing -::
* Argument abbreviations (prefix matching): Argument abbreviations prefix matching.
* Beyond sys.argv: Beyond sys argv.
* The Namespace object::

Other utilities

* Subcommands::
* FileType objects::
* Argument groups::
* Mutual exclusion::
* Parser defaults::
* Printing help::
* Partial parsing::
* Customizing file parsing::
* Exiting methods::
* Intermixed parsing::
* Registering custom types or actions::

Exceptions

* Argparse Tutorial::
* Migrating optparse code to argparse::

Argparse Tutorial

* Concepts::
* The basics::
* Introducing Positional arguments::
* Introducing Optional arguments::
* Combining Positional and Optional arguments::
* Getting a little more advanced::
* How to translate the argparse output::
* Custom type converters::
* Conclusion::

Introducing Optional arguments

* Short options::

Getting a little more advanced

* Specifying ambiguous arguments::
* Conflicting options::

optparse — Parser for command line options

* Choosing an argument parsing library::
* Introduction: Introduction<7>.
* Background::
* Tutorial: Tutorial<2>.
* Reference Guide::
* Option Callbacks::
* Extending optparse::
* Exceptions: Exceptions<10>.

Background

* Terminology::
* What are options for?::
* What are positional arguments for?::

Tutorial

* Understanding option actions::
* The store action::
* Handling boolean (flag) options: Handling boolean flag options.
* Other actions::
* Default values::
* Generating help::
* Printing a version string::
* How optparse handles errors::
* Putting it all together::

Generating help

* Grouping Options::

Reference Guide

* Creating the parser::
* Populating the parser::
* Defining options::
* Option attributes::
* Standard option actions::
* Standard option types::
* Parsing arguments::
* Querying and manipulating your option parser::
* Conflicts between options::
* Cleanup::
* Other methods::

Option Callbacks

* Defining a callback option::
* How callbacks are called::
* Raising errors in a callback::
* Callback example 1; trivial callback: Callback example 1 trivial callback.
* Callback example 2; check option order: Callback example 2 check option order.
* Callback example 3; check option order (generalized): Callback example 3 check option order generalized.
* Callback example 4; check arbitrary condition: Callback example 4 check arbitrary condition.
* Callback example 5; fixed arguments: Callback example 5 fixed arguments.
* Callback example 6; variable arguments: Callback example 6 variable arguments.

Extending optparse

* Adding new types::
* Adding new actions::

curses — Terminal handling for character-cell displays

* Functions: Functions<6>.
* Window Objects::
* Constants: Constants<6>.

curses.textpad — Text input widget for curses programs

* Textbox objects::

curses.panel — A panel stack extension for curses

* Functions: Functions<7>.
* Panel Objects::

cmd — Support for line-oriented command interpreters

* Cmd Objects::
* Cmd Example::

Concurrent Execution

* threading — Thread-based parallelism::
* multiprocessing — Process-based parallelism::
* multiprocessing.shared_memory — Shared memory for direct access across processes: multiprocessing shared_memory — Shared memory for direct access across processes.
* The concurrent package::
* concurrent.futures — Launching parallel tasks: concurrent futures — Launching parallel tasks.
* subprocess — Subprocess management::
* sched — Event scheduler::
* queue — A synchronized queue class::
* contextvars — Context Variables::
* _thread — Low-level threading API::

threading — Thread-based parallelism

* Introduction: Introduction<8>.
* GIL and performance considerations::
* Reference: Reference<2>.
* Using locks, conditions, and semaphores in the with statement: Using locks conditions and semaphores in the with statement.

Reference

* Thread-local data::
* Thread objects::
* Lock objects::
* RLock objects::
* Condition objects::
* Semaphore objects::
* Semaphore example::
* Event objects::
* Timer objects::
* Barrier objects::

multiprocessing — Process-based parallelism

* Introduction: Introduction<9>.
* Reference: Reference<3>.
* Programming guidelines::
* Examples: Examples<14>.

Introduction

* The Process class::
* Contexts and start methods::
* Exchanging objects between processes::
* Synchronization between processes::
* Sharing state between processes::
* Using a pool of workers::

Reference

* Global start method::
* Process and exceptions::
* Pipes and Queues::
* Miscellaneous: Miscellaneous<3>.
* Connection Objects::
* Synchronization primitives::
* Shared ctypes Objects::
* Managers::
* Proxy Objects::
* Process Pools::
* Listeners and Clients::
* Authentication keys::
* Logging: Logging<2>.
* The multiprocessing.dummy module: The multiprocessing dummy module.

Shared ctypes Objects

* The multiprocessing.sharedctypes module: The multiprocessing sharedctypes module.

Managers

* Customized managers::
* Using a remote manager::

Proxy Objects

* Cleanup: Cleanup<2>.

Listeners and Clients

* Address Formats::

Programming guidelines

* All start methods::
* The spawn and forkserver start methods::

concurrent.futures — Launching parallel tasks

* Executor Objects::
* ThreadPoolExecutor::
* ProcessPoolExecutor::
* Future Objects::
* Module Functions::
* Exception classes::

ThreadPoolExecutor

* ThreadPoolExecutor Example::

ProcessPoolExecutor

* ProcessPoolExecutor Example::

subprocess — Subprocess management

* Using the subprocess Module::
* Security Considerations::
* Popen Objects::
* Windows Popen Helpers::
* Older high-level API::
* Replacing Older Functions with the subprocess Module::
* Legacy Shell Invocation Functions::
* Notes: Notes<2>.

Using the subprocess Module

* Frequently Used Arguments::
* Popen Constructor::
* Exceptions: Exceptions<11>.

Windows Popen Helpers

* Windows Constants::

Replacing Older Functions with the subprocess Module

* Replacing /bin/sh shell command substitution::
* Replacing shell pipeline::
* Replacing os.system(): Replacing os system.
* Replacing the os.spawn family: Replacing the os spawn family.
* Replacing os.popen(), os.popen2(), os.popen3(): Replacing os popen os popen2 os popen3.
* Replacing functions from the popen2 module::

Notes

* Timeout Behavior::
* Converting an argument sequence to a string on Windows::
* Disabling use of vfork() or posix_spawn(): Disabling use of vfork or posix_spawn.

sched — Event scheduler

* Scheduler Objects::

queue — A synchronized queue class

* Queue Objects::
* SimpleQueue Objects::

Queue Objects

* Waiting for task completion::
* Terminating queues::

contextvars — Context Variables

* Context Variables::
* Manual Context Management::
* asyncio support::

Networking and Interprocess Communication

* asyncio — Asynchronous I/O::
* socket — Low-level networking interface::
* ssl — TLS/SSL wrapper for socket objects::
* select — Waiting for I/O completion::
* selectors — High-level I/O multiplexing::
* signal — Set handlers for asynchronous events::
* mmap — Memory-mapped file support::

asyncio — Asynchronous I/O

* Runners::
* Coroutines and tasks::
* Streams::
* Synchronization Primitives::
* Subprocesses::
* Queues::
* Exceptions: Exceptions<13>.
* Event loop::
* Futures::
* Transports and Protocols::
* Policies::
* Platform Support::
* Extending::
* High-level API Index::
* Low-level API Index::
* Developing with asyncio::

Runners

* Running an asyncio Program::
* Runner context manager::
* Handling Keyboard Interruption::

Coroutines and tasks

* Coroutines: Coroutines<3>.
* Awaitables::
* Creating tasks::
* Task cancellation::
* Task groups::
* Sleeping::
* Running tasks concurrently::
* Eager task factory::
* Shielding from cancellation::
* Timeouts::
* Waiting primitives::
* Running in threads::
* Scheduling from other threads::
* Introspection::
* Task object::

Task groups

* Terminating a task group::

Streams

* StreamReader::
* StreamWriter::
* Examples: Examples<15>.

Examples

* TCP echo client using streams::
* TCP echo server using streams::
* Get HTTP headers::
* Register an open socket to wait for data using streams::

Synchronization Primitives

* Lock::
* Event::
* Condition::
* Semaphore::
* BoundedSemaphore::
* Barrier::

Subprocesses

* Creating Subprocesses::
* Constants: Constants<7>.
* Interacting with Subprocesses::

Interacting with Subprocesses

* Subprocess and Threads::
* Examples: Examples<16>.

Queues

* Queue::
* Priority Queue::
* LIFO Queue::
* Exceptions: Exceptions<12>.
* Examples: Examples<17>.

Event loop

* Event loop methods::
* Callback handles::
* Server objects::
* Event loop implementations::
* Examples: Examples<18>.

Event loop methods

* Running and stopping the loop::
* Scheduling callbacks::
* Scheduling delayed callbacks::
* Creating futures and tasks::
* Opening network connections::
* Creating network servers::
* Transferring files::
* TLS upgrade::
* Watching file descriptors::
* Working with socket objects directly::
* DNS::
* Working with pipes::
* Unix signals::
* Executing code in thread or process pools::
* Error handling API::
* Enabling debug mode::
* Running subprocesses::

Examples

* Hello World with call_soon(): Hello World with call_soon.
* Display the current date with call_later(): Display the current date with call_later.
* Watch a file descriptor for read events::
* Set signal handlers for SIGINT and SIGTERM::

Futures

* Future Functions::
* Future Object::

Transports and Protocols

* Transports::
* Protocols::
* Examples: Examples<19>.

Transports

* Transports Hierarchy::
* Base Transport::
* Read-only Transports::
* Write-only Transports::
* Datagram Transports::
* Subprocess Transports::

Protocols

* Base Protocols::
* Base Protocol::
* Streaming Protocols::
* Buffered Streaming Protocols::
* Datagram Protocols::
* Subprocess Protocols::

Examples

* TCP Echo Server::
* TCP Echo Client::
* UDP Echo Server::
* UDP Echo Client::
* Connecting Existing Sockets::
* loop.subprocess_exec() and SubprocessProtocol: loop subprocess_exec and SubprocessProtocol.

Policies

* Getting and Setting the Policy::
* Policy Objects::
* Process Watchers::
* Custom Policies::

Platform Support

* All Platforms::
* Windows: Windows<82>.
* macOS: macOS<52>.

Windows

* Subprocess Support on Windows::

Extending

* Writing a Custom Event Loop::
* Future and Task private constructors::
* Task lifetime support::

High-level API Index

* Tasks::
* Queues: Queues<2>.
* Subprocesses: Subprocesses<2>.
* Streams: Streams<2>.
* Synchronization::
* Exceptions: Exceptions<14>.

Low-level API Index

* Obtaining the Event Loop::
* Event Loop Methods::
* Transports: Transports<2>.
* Protocols: Protocols<2>.
* Event Loop Policies::

Developing with asyncio

* Debug Mode::
* Concurrency and Multithreading::
* Running Blocking Code::
* Logging: Logging<3>.
* Detect never-awaited coroutines::
* Detect never-retrieved exceptions::
* Asynchronous generators best practices::

Asynchronous generators best practices

* Close asynchronous generators explicitly::
* Create asynchronous generators only when the event loop is running::
* Avoid concurrent iteration and closure of the same generator::

socket — Low-level networking interface

* Socket families::
* Module contents: Module contents<2>.
* Socket Objects::
* Notes on socket timeouts::
* Example: Example<7>.

Module contents

* Exceptions: Exceptions<15>.
* Constants: Constants<8>.
* Functions: Functions<8>.

Functions

* Creating sockets::
* Other functions: Other functions<2>.

Notes on socket timeouts

* Timeouts and the connect method::
* Timeouts and the accept method::

ssl — TLS/SSL wrapper for socket objects

* Functions, constants, and exceptions: Functions constants and exceptions.
* SSL sockets::
* SSL contexts::
* Certificates::
* Examples: Examples<20>.
* Notes on non-blocking sockets::
* Memory BIO support::
* SSL session::
* Security considerations: Security considerations<2>.
* TLS 1.3: TLS 1 3.

Functions, constants, and exceptions

* Socket creation::
* Context creation::
* Exceptions: Exceptions<16>.
* Random generation::
* Certificate handling::
* Constants: Constants<9>.

Certificates

* Certificate chains::
* CA certificates::
* Combined key and certificate::
* Self-signed certificates::

Examples

* Testing for SSL support::
* Client-side operation::
* Server-side operation::

Security considerations

* Best defaults::
* Manual settings::
* Multi-processing::

Manual settings

* Verifying certificates::
* Protocol versions::
* Cipher selection::

select — Waiting for I/O completion

* /dev/poll Polling Objects::
* Edge and Level Trigger Polling (epoll) Objects: Edge and Level Trigger Polling epoll Objects.
* Polling Objects::
* Kqueue Objects::
* Kevent Objects::

selectors — High-level I/O multiplexing

* Introduction: Introduction<10>.
* Classes: Classes<4>.
* Examples: Examples<21>.

signal — Set handlers for asynchronous events

* General rules::
* Module contents: Module contents<3>.
* Examples: Examples<22>.
* Note on SIGPIPE::
* Note on Signal Handlers and Exceptions::

General rules

* Execution of Python signal handlers::
* Signals and threads::

mmap — Memory-mapped file support

* MADV_* Constants::
* MAP_* Constants::

Internet Data Handling

* email — An email and MIME handling package::
* json — JSON encoder and decoder::
* mailbox — Manipulate mailboxes in various formats::
* mimetypes — Map filenames to MIME types::
* base64 — Base16, Base32, Base64, Base85 Data Encodings: base64 — Base16 Base32 Base64 Base85 Data Encodings.
* binascii — Convert between binary and ASCII::
* quopri — Encode and decode MIME quoted-printable data::

email — An email and MIME handling package

* email.message; Representing an email message: email message Representing an email message.
* email.parser; Parsing email messages: email parser Parsing email messages.
* email.generator; Generating MIME documents: email generator Generating MIME documents.
* email.policy; Policy Objects: email policy Policy Objects.
* email.errors; Exception and Defect classes: email errors Exception and Defect classes.
* email.headerregistry; Custom Header Objects: email headerregistry Custom Header Objects.
* email.contentmanager; Managing MIME Content: email contentmanager Managing MIME Content.
* email; Examples: email Examples.
* email.message.Message; Representing an email message using the compat32 API: email message Message Representing an email message using the compat32 API.
* email.mime; Creating email and MIME objects from scratch: email mime Creating email and MIME objects from scratch.
* email.header; Internationalized headers: email header Internationalized headers.
* email.charset; Representing character sets: email charset Representing character sets.
* email.encoders; Encoders: email encoders Encoders.
* email.utils; Miscellaneous utilities: email utils Miscellaneous utilities.
* email.iterators; Iterators: email iterators Iterators.

email.parser: Parsing email messages

* FeedParser API::
* Parser API::
* Additional notes::

email.contentmanager: Managing MIME Content

* Content Manager Instances::

json — JSON encoder and decoder

* Basic Usage::
* Encoders and Decoders::
* Exceptions: Exceptions<17>.
* Standard Compliance and Interoperability::
* Command Line Interface::

Standard Compliance and Interoperability

* Character Encodings::
* Infinite and NaN Number Values::
* Repeated Names Within an Object::
* Top-level Non-Object, Non-Array Values: Top-level Non-Object Non-Array Values.
* Implementation Limitations::

Command Line Interface

* Command line options::

mailbox — Manipulate mailboxes in various formats

* Mailbox objects::
* Message objects::
* Exceptions: Exceptions<18>.
* Examples: Examples<23>.

Mailbox objects

* Maildir objects::
* mbox objects::
* MH objects::
* Babyl objects::
* MMDF objects::

Message objects

* MaildirMessage objects::
* mboxMessage objects::
* MHMessage objects::
* BabylMessage objects::
* MMDFMessage objects::

mimetypes — Map filenames to MIME types

* MimeTypes Objects::

base64 — Base16, Base32, Base64, Base85 Data Encodings

* RFC 4648 Encodings::
* Base85 Encodings::
* Legacy Interface::
* Security Considerations: Security Considerations<2>.

Structured Markup Processing Tools

* html — HyperText Markup Language support::
* html.parser — Simple HTML and XHTML parser: html parser — Simple HTML and XHTML parser.
* html.entities — Definitions of HTML general entities: html entities — Definitions of HTML general entities.
* XML Processing Modules::
* xml.etree.ElementTree — The ElementTree XML API: xml etree ElementTree — The ElementTree XML API.
* xml.dom — The Document Object Model API: xml dom — The Document Object Model API.
* xml.dom.minidom — Minimal DOM implementation: xml dom minidom — Minimal DOM implementation.
* xml.dom.pulldom — Support for building partial DOM trees: xml dom pulldom — Support for building partial DOM trees.
* xml.sax — Support for SAX2 parsers: xml sax — Support for SAX2 parsers.
* xml.sax.handler — Base classes for SAX handlers: xml sax handler — Base classes for SAX handlers.
* xml.sax.saxutils — SAX Utilities: xml sax saxutils — SAX Utilities.
* xml.sax.xmlreader — Interface for XML parsers: xml sax xmlreader — Interface for XML parsers.
* xml.parsers.expat — Fast XML parsing using Expat: xml parsers expat — Fast XML parsing using Expat.

html.parser — Simple HTML and XHTML parser

* Example HTML Parser Application::
* HTMLParser Methods::
* Examples: Examples<24>.

XML Processing Modules

* XML security::

xml.etree.ElementTree — The ElementTree XML API

* Tutorial: Tutorial<3>.
* XPath support::
* Reference: Reference<4>.
* XInclude support::
* Reference: Reference<5>.

Tutorial

* XML tree and elements::
* Parsing XML::
* Pull API for non-blocking parsing::
* Finding interesting elements::
* Modifying an XML File::
* Building XML documents::
* Parsing XML with Namespaces::

XPath support

* Example: Example<8>.
* Supported XPath syntax::

Reference

* Functions: Functions<9>.

XInclude support

* Example: Example<9>.

Reference

* Functions: Functions<10>.
* Element Objects::
* ElementTree Objects::
* QName Objects::
* TreeBuilder Objects::
* XMLParser Objects::
* XMLPullParser Objects::
* Exceptions: Exceptions<19>.

xml.dom — The Document Object Model API

* Module Contents: Module Contents<3>.
* Objects in the DOM::
* Conformance::

Objects in the DOM

* DOMImplementation Objects::
* Node Objects::
* NodeList Objects::
* DocumentType Objects::
* Document Objects::
* Element Objects: Element Objects<2>.
* Attr Objects::
* NamedNodeMap Objects::
* Comment Objects::
* Text and CDATASection Objects::
* ProcessingInstruction Objects::
* Exceptions: Exceptions<20>.

Conformance

* Type Mapping::
* Accessor Methods::

xml.dom.minidom — Minimal DOM implementation

* DOM Objects::
* DOM Example::
* minidom and the DOM standard::

xml.dom.pulldom — Support for building partial DOM trees

* DOMEventStream Objects::

xml.sax — Support for SAX2 parsers

* SAXException Objects::

xml.sax.handler — Base classes for SAX handlers

* ContentHandler Objects::
* DTDHandler Objects::
* EntityResolver Objects::
* ErrorHandler Objects::
* LexicalHandler Objects::

xml.sax.xmlreader — Interface for XML parsers

* XMLReader Objects::
* IncrementalParser Objects::
* Locator Objects::
* InputSource Objects::
* The Attributes Interface::
* The AttributesNS Interface::

xml.parsers.expat — Fast XML parsing using Expat

* XMLParser Objects: XMLParser Objects<2>.
* ExpatError Exceptions::
* Example: Example<10>.
* Content Model Descriptions::
* Expat error constants::

Internet Protocols and Support

* webbrowser — Convenient web-browser controller::
* wsgiref — WSGI Utilities and Reference Implementation::
* urllib — URL handling modules::
* urllib.request — Extensible library for opening URLs: urllib request — Extensible library for opening URLs.
* urllib.response — Response classes used by urllib: urllib response — Response classes used by urllib.
* urllib.parse — Parse URLs into components: urllib parse — Parse URLs into components.
* urllib.error — Exception classes raised by urllib.request: urllib error — Exception classes raised by urllib request.
* urllib.robotparser — Parser for robots.txt: urllib robotparser — Parser for robots txt.
* http — HTTP modules::
* http.client — HTTP protocol client: http client — HTTP protocol client.
* ftplib — FTP protocol client::
* poplib — POP3 protocol client::
* imaplib — IMAP4 protocol client::
* smtplib — SMTP protocol client::
* uuid — UUID objects according to RFC 4122::
* socketserver — A framework for network servers::
* http.server — HTTP servers: http server — HTTP servers.
* http.cookies — HTTP state management: http cookies — HTTP state management.
* http.cookiejar — Cookie handling for HTTP clients: http cookiejar — Cookie handling for HTTP clients.
* xmlrpc — XMLRPC server and client modules::
* xmlrpc.client — XML-RPC client access: xmlrpc client — XML-RPC client access.
* xmlrpc.server — Basic XML-RPC servers: xmlrpc server — Basic XML-RPC servers.
* ipaddress — IPv4/IPv6 manipulation library::

webbrowser — Convenient web-browser controller

* Command-line interface: Command-line interface<4>.
* Browser controller objects::

wsgiref — WSGI Utilities and Reference Implementation

* wsgiref.util – WSGI environment utilities: wsgiref util – WSGI environment utilities.
* wsgiref.headers – WSGI response header tools: wsgiref headers – WSGI response header tools.
* wsgiref.simple_server – a simple WSGI HTTP server: wsgiref simple_server – a simple WSGI HTTP server.
* wsgiref.validate — WSGI conformance checker: wsgiref validate — WSGI conformance checker.
* wsgiref.handlers – server/gateway base classes: wsgiref handlers – server/gateway base classes.
* wsgiref.types – WSGI types for static type checking: wsgiref types – WSGI types for static type checking.
* Examples: Examples<25>.

urllib.request — Extensible library for opening URLs

* Request Objects::
* OpenerDirector Objects::
* BaseHandler Objects::
* HTTPRedirectHandler Objects::
* HTTPCookieProcessor Objects::
* ProxyHandler Objects::
* HTTPPasswordMgr Objects::
* HTTPPasswordMgrWithPriorAuth Objects::
* AbstractBasicAuthHandler Objects::
* HTTPBasicAuthHandler Objects::
* ProxyBasicAuthHandler Objects::
* AbstractDigestAuthHandler Objects::
* HTTPDigestAuthHandler Objects::
* ProxyDigestAuthHandler Objects::
* HTTPHandler Objects::
* HTTPSHandler Objects::
* FileHandler Objects::
* DataHandler Objects::
* FTPHandler Objects::
* CacheFTPHandler Objects::
* UnknownHandler Objects::
* HTTPErrorProcessor Objects::
* Examples: Examples<26>.
* Legacy interface::
* urllib.request Restrictions: urllib request Restrictions.

urllib.parse — Parse URLs into components

* URL Parsing::
* URL parsing security::
* Parsing ASCII Encoded Bytes::
* Structured Parse Results::
* URL Quoting::

http — HTTP modules

* HTTP status codes::
* HTTP status category::
* HTTP methods::

http.client — HTTP protocol client

* HTTPConnection Objects::
* HTTPResponse Objects::
* Examples: Examples<27>.
* HTTPMessage Objects::

ftplib — FTP protocol client

* Reference: Reference<6>.

Reference

* FTP objects::
* FTP_TLS objects::
* Module variables::

poplib — POP3 protocol client

* POP3 Objects::
* POP3 Example::

imaplib — IMAP4 protocol client

* IMAP4 Objects::
* IMAP4 Example::

smtplib — SMTP protocol client

* SMTP Objects::
* SMTP Example::

uuid — UUID objects according to RFC 4122

* Command-Line Usage: Command-Line Usage<2>.
* Example: Example<11>.
* Command-Line Example::

socketserver — A framework for network servers

* Server Creation Notes::
* Server Objects::
* Request Handler Objects::
* Examples: Examples<28>.

Examples

* socketserver.TCPServer Example: socketserver TCPServer Example.
* socketserver.UDPServer Example: socketserver UDPServer Example.
* Asynchronous Mixins::

http.server — HTTP servers

* Command-line interface: Command-line interface<5>.
* Security considerations: Security considerations<3>.

http.cookies — HTTP state management

* Cookie Objects::
* Morsel Objects::
* Example: Example<12>.

http.cookiejar — Cookie handling for HTTP clients

* CookieJar and FileCookieJar Objects::
* FileCookieJar subclasses and co-operation with web browsers::
* CookiePolicy Objects::
* DefaultCookiePolicy Objects::
* Cookie Objects: Cookie Objects<2>.
* Examples: Examples<29>.

xmlrpc.client — XML-RPC client access

* ServerProxy Objects::
* DateTime Objects::
* Binary Objects::
* Fault Objects::
* ProtocolError Objects::
* MultiCall Objects::
* Convenience Functions::
* Example of Client Usage::
* Example of Client and Server Usage::

xmlrpc.server — Basic XML-RPC servers

* SimpleXMLRPCServer objects::
* CGIXMLRPCRequestHandler::
* Documenting XMLRPC server::
* DocXMLRPCServer objects::
* DocCGIXMLRPCRequestHandler::

SimpleXMLRPCServer objects

* SimpleXMLRPCServer example::

ipaddress — IPv4/IPv6 manipulation library

* Convenience factory functions::
* IP Addresses::
* IP Network definitions::
* Interface objects::
* Other Module Level Functions::
* Custom Exceptions::

IP Addresses

* Address objects::
* Conversion to Strings and Integers::
* Operators: Operators<3>.

Operators

* Comparison operators::
* Arithmetic operators::

IP Network definitions

* Prefix, net mask and host mask: Prefix net mask and host mask.
* Network objects::
* Operators: Operators<4>.

Operators

* Logical operators::
* Iteration::
* Networks as containers of addresses::

Interface objects

* Operators: Operators<5>.

Operators

* Logical operators: Logical operators<2>.

Multimedia Services

* wave — Read and write WAV files::
* colorsys — Conversions between color systems::

wave — Read and write WAV files

* Wave_read Objects::
* Wave_write Objects::

Internationalization

* gettext — Multilingual internationalization services::
* locale — Internationalization services::

gettext — Multilingual internationalization services

* GNU gettext API::
* Class-based API::
* Internationalizing your programs and modules::
* Acknowledgements: Acknowledgements<9>.

Class-based API

* The NullTranslations class::
* The GNUTranslations class::
* Solaris message catalog support::
* The Catalog constructor::

Internationalizing your programs and modules

* Localizing your module::
* Localizing your application::
* Changing languages on the fly::
* Deferred translations::

locale — Internationalization services

* Background, details, hints, tips and caveats: Background details hints tips and caveats.
* Locale names::
* For extension writers and programs that embed Python::
* Access to message catalogs::

Graphical user interfaces with Tk

* tkinter — Python interface to Tcl/Tk::
* tkinter.colorchooser — Color choosing dialog: tkinter colorchooser — Color choosing dialog.
* tkinter.font — Tkinter font wrapper: tkinter font — Tkinter font wrapper.
* Tkinter Dialogs::
* tkinter.messagebox — Tkinter message prompts: tkinter messagebox — Tkinter message prompts.
* tkinter.scrolledtext — Scrolled Text Widget: tkinter scrolledtext — Scrolled Text Widget.
* tkinter.dnd — Drag and drop support: tkinter dnd — Drag and drop support.
* tkinter.ttk — Tk themed widgets: tkinter ttk — Tk themed widgets.
* IDLE — Python editor and shell: IDLE — Python editor and shell<2>.
* turtle — Turtle graphics::

tkinter — Python interface to Tcl/Tk

* Architecture::
* Tkinter Modules::
* Tkinter Life Preserver::
* Threading model::
* Handy Reference::
* File Handlers::

Tkinter Life Preserver

* A Hello World Program::
* Important Tk Concepts::
* Understanding How Tkinter Wraps Tcl/Tk::
* How do I…? What option does…?::
* Navigating the Tcl/Tk Reference Manual::

Handy Reference

* Setting Options::
* The Packer::
* Packer Options::
* Coupling Widget Variables::
* The Window Manager::
* Tk Option Data Types::
* Bindings and Events::
* The index Parameter::
* Images::

Tkinter Dialogs

* tkinter.simpledialog — Standard Tkinter input dialogs: tkinter simpledialog — Standard Tkinter input dialogs.
* tkinter.filedialog — File selection dialogs: tkinter filedialog — File selection dialogs.
* tkinter.commondialog — Dialog window templates: tkinter commondialog — Dialog window templates.

tkinter.filedialog — File selection dialogs

* Native Load/Save Dialogs::

tkinter.ttk — Tk themed widgets

* Using Ttk::
* Ttk Widgets::
* Widget::
* Combobox::
* Spinbox::
* Notebook::
* Progressbar::
* Separator::
* Sizegrip::
* Treeview::
* Ttk Styling::

Widget

* Standard Options::
* Scrollable Widget Options::
* Label Options::
* Compatibility Options::
* Widget States::
* ttk.Widget: ttk Widget.

Combobox

* Options::
* Virtual events::
* ttk.Combobox: ttk Combobox.

Spinbox

* Options: Options<2>.
* Virtual events: Virtual events<2>.
* ttk.Spinbox: ttk Spinbox.

Notebook

* Options: Options<3>.
* Tab Options::
* Tab Identifiers::
* Virtual Events::
* ttk.Notebook: ttk Notebook.

Progressbar

* Options: Options<4>.
* ttk.Progressbar: ttk Progressbar.

Separator

* Options: Options<5>.

Sizegrip

* Platform-specific notes::
* Bugs::

Treeview

* Options: Options<6>.
* Item Options::
* Tag Options::
* Column Identifiers::
* Virtual Events: Virtual Events<2>.
* ttk.Treeview: ttk Treeview.

Ttk Styling

* Layouts::

IDLE — Python editor and shell

* Menus::
* Editing and Navigation::
* Startup and Code Execution::
* Help and Preferences::
* idlelib — implementation of IDLE application::

Menus

* File menu (Shell and Editor): File menu Shell and Editor.
* Edit menu (Shell and Editor): Edit menu Shell and Editor.
* Format menu (Editor window only): Format menu Editor window only.
* Run menu (Editor window only): Run menu Editor window only.
* Shell menu (Shell window only): Shell menu Shell window only.
* Debug menu (Shell window only): Debug menu Shell window only.
* Options menu (Shell and Editor): Options menu Shell and Editor.
* Window menu (Shell and Editor): Window menu Shell and Editor.
* Help menu (Shell and Editor): Help menu Shell and Editor.
* Context menus::

Editing and Navigation

* Editor windows::
* Key bindings::
* Automatic indentation::
* Search and Replace::
* Completions::
* Calltips::
* Format block::
* Code Context::
* Shell window::
* Text colors::

Startup and Code Execution

* Command-line usage: Command-line usage<3>.
* Startup failure::
* Running user code::
* User output in Shell::
* Developing tkinter applications::
* Running without a subprocess::

Help and Preferences

* Help sources::
* Setting preferences::
* IDLE on macOS::
* Extensions::

turtle — Turtle graphics

* Introduction: Introduction<11>.
* Get started::
* Tutorial: Tutorial<4>.
* How to…::
* Turtle graphics reference::
* Methods of RawTurtle/Turtle and corresponding functions::
* Methods of TurtleScreen/Screen and corresponding functions::
* Public classes::
* Explanation: Explanation<2>.
* Help and configuration::
* turtledemo — Demo scripts::
* Changes since Python 2.6: Changes since Python 2 6.
* Changes since Python 3.0: Changes since Python 3 0.

Tutorial

* Starting a turtle environment::
* Basic drawing::
* Making algorithmic patterns::

Basic drawing

* Pen control::
* The turtle’s position::

How to…

* Get started as quickly as possible::
* Use the turtle module namespace::
* Use turtle graphics in a script::
* Use object-oriented turtle graphics::

Turtle graphics reference

* Turtle methods::
* Methods of TurtleScreen/Screen::

Methods of RawTurtle/Turtle and corresponding functions

* Turtle motion::
* Tell Turtle’s state::
* Settings for measurement::
* Pen control: Pen control<2>.
* Turtle state::
* Using events::
* Special Turtle methods::
* Compound shapes::

Pen control

* Drawing state::
* Color control::
* Filling::
* More drawing control::

Turtle state

* Visibility::
* Appearance::

Methods of TurtleScreen/Screen and corresponding functions

* Window control::
* Animation control::
* Using screen events::
* Input methods::
* Settings and special methods::
* Methods specific to Screen, not inherited from TurtleScreen: Methods specific to Screen not inherited from TurtleScreen.

Help and configuration

* How to use help::
* Translation of docstrings into different languages::
* How to configure Screen and Turtles::

Development Tools

* typing — Support for type hints::
* pydoc — Documentation generator and online help system::
* Python Development Mode::
* doctest — Test interactive Python examples::
* unittest — Unit testing framework::
* unittest.mock — mock object library: unittest mock — mock object library.
* unittest.mock — getting started: unittest mock — getting started.
* test — Regression tests package for Python::
* test.support — Utilities for the Python test suite: test support — Utilities for the Python test suite.
* test.support.socket_helper — Utilities for socket tests: test support socket_helper — Utilities for socket tests.
* test.support.script_helper — Utilities for the Python execution tests: test support script_helper — Utilities for the Python execution tests.
* test.support.bytecode_helper — Support tools for testing correct bytecode generation: test support bytecode_helper — Support tools for testing correct bytecode generation.
* test.support.threading_helper — Utilities for threading tests: test support threading_helper — Utilities for threading tests.
* test.support.os_helper — Utilities for os tests: test support os_helper — Utilities for os tests.
* test.support.import_helper — Utilities for import tests: test support import_helper — Utilities for import tests.
* test.support.warnings_helper — Utilities for warnings tests: test support warnings_helper — Utilities for warnings tests.

typing — Support for type hints

* Specification for the Python Type System::
* Type aliases::
* NewType::
* Annotating callable objects::
* Generics::
* Annotating tuples::
* The type of class objects::
* Annotating generators and coroutines::
* User-defined generic types::
* The Any type::
* Nominal vs structural subtyping::
* Module contents: Module contents<4>.
* Deprecation Timeline of Major Features::

Module contents

* Special typing primitives::
* Protocols: Protocols<3>.
* ABCs for working with IO::
* Functions and decorators::
* Introspection helpers::
* Constant::
* Deprecated aliases::

Special typing primitives

* Special types::
* Special forms::
* Building generic types and type aliases::
* Other special directives::

Deprecated aliases

* Aliases to built-in types::
* Aliases to types in collections::
* Aliases to other concrete types::
* Aliases to container ABCs in collections.abc: Aliases to container ABCs in collections abc.
* Aliases to asynchronous ABCs in collections.abc: Aliases to asynchronous ABCs in collections abc.
* Aliases to other ABCs in collections.abc: Aliases to other ABCs in collections abc.
* Aliases to contextlib ABCs::

Python Development Mode

* Effects of the Python Development Mode::
* ResourceWarning Example::
* Bad file descriptor error example::

doctest — Test interactive Python examples

* Simple Usage; Checking Examples in Docstrings: Simple Usage Checking Examples in Docstrings.
* Simple Usage; Checking Examples in a Text File: Simple Usage Checking Examples in a Text File.
* Command-line Usage::
* How It Works::
* Basic API::
* Unittest API::
* Advanced API::
* Debugging::
* Soapbox::

How It Works

* Which Docstrings Are Examined?::
* How are Docstring Examples Recognized?::
* What’s the Execution Context?::
* What About Exceptions?::
* Option Flags::
* Directives::
* Warnings: Warnings<2>.

Advanced API

* DocTest Objects::
* Example Objects::
* DocTestFinder objects::
* DocTestParser objects::
* TestResults objects::
* DocTestRunner objects::
* OutputChecker objects::

unittest — Unit testing framework

* Basic example::
* Command-Line Interface: Command-Line Interface<2>.
* Test Discovery::
* Organizing test code::
* Re-using old test code::
* Skipping tests and expected failures::
* Distinguishing test iterations using subtests::
* Classes and functions::
* Class and Module Fixtures::
* Signal Handling::

Command-Line Interface

* Command-line options: Command-line options<4>.

Classes and functions

* Test cases::
* Grouping tests::
* Loading and running tests::

Loading and running tests

* load_tests Protocol::

Class and Module Fixtures

* setUpClass and tearDownClass::
* setUpModule and tearDownModule::

unittest.mock — mock object library

* Quick Guide::
* The Mock Class::
* The patchers::
* MagicMock and magic method support::
* Helpers::
* Order of precedence of side_effect, return_value and wraps: Order of precedence of side_effect return_value and wraps.

The Mock Class

* Calling::
* Deleting Attributes::
* Mock names and the name attribute::
* Attaching Mocks as Attributes::

The patchers

* patch::
* patch.object: patch object.
* patch.dict: patch dict.
* patch.multiple: patch multiple.
* patch methods; start and stop: patch methods start and stop.
* patch builtins::
* TEST_PREFIX::
* Nesting Patch Decorators::
* Where to patch::
* Patching Descriptors and Proxy Objects::

MagicMock and magic method support

* Mocking Magic Methods::
* Magic Mock::

Helpers

* sentinel::
* DEFAULT::
* call::
* create_autospec::
* ANY::
* FILTER_DIR::
* mock_open::
* Autospeccing::
* Sealing mocks::

unittest.mock — getting started

* Using Mock::
* Patch decorators::
* Further examples::

Using Mock

* Mock patching methods::
* Mock for method calls on an object::
* Mocking classes::
* Naming your mocks::
* Tracking all calls::
* Setting return values and attributes::
* Raising exceptions with mocks::
* Side effect functions and iterables::
* Mocking asynchronous iterators::
* Mocking asynchronous context manager::
* Creating a mock from an existing object::
* Using side_effect to return per file content::

Further examples

* Mocking chained calls::
* Partial mocking::
* Mocking a generator method::
* Applying the same patch to every test method::
* Mocking unbound methods::
* Checking multiple calls with mock::
* Coping with mutable arguments::
* Nesting patches::
* Mocking a dictionary with MagicMock::
* Mock subclasses and their attributes::
* Mocking imports with patch.dict: Mocking imports with patch dict.
* Tracking order of calls and less verbose call assertions::
* More complex argument matching::

test — Regression tests package for Python

* Writing Unit Tests for the test package::
* Running tests using the command-line interface::

Debugging and Profiling

* Audit events table::
* bdb — Debugger framework::
* faulthandler — Dump the Python traceback::
* pdb — The Python Debugger::
* The Python Profilers::
* timeit — Measure execution time of small code snippets::
* trace — Trace or track Python statement execution::
* tracemalloc — Trace memory allocations::

faulthandler — Dump the Python traceback

* Dumping the traceback::
* Fault handler state::
* Dumping the tracebacks after a timeout::
* Dumping the traceback on a user signal::
* Issue with file descriptors::
* Example: Example<13>.

pdb — The Python Debugger

* Command-line interface: Command-line interface<6>.
* Debugger commands::

The Python Profilers

* Introduction to the profilers::
* Instant User’s Manual::
* profile and cProfile Module Reference::
* The Stats Class::
* What Is Deterministic Profiling?::
* Limitations::
* Calibration::
* Using a custom timer::

timeit — Measure execution time of small code snippets

* Basic Examples: Basic Examples<2>.
* Python Interface::
* Command-Line Interface: Command-Line Interface<3>.
* Examples: Examples<30>.

trace — Trace or track Python statement execution

* Command-Line Usage: Command-Line Usage<3>.
* Programmatic Interface::

Command-Line Usage

* Main options::
* Modifiers::
* Filters::

tracemalloc — Trace memory allocations

* Examples: Examples<31>.
* API::

Examples

* Display the top 10::
* Compute differences::
* Get the traceback of a memory block::
* Pretty top::

Pretty top

* Record the current and peak size of all traced memory blocks::

API

* Functions: Functions<11>.
* DomainFilter::
* Filter::
* Frame::
* Snapshot::
* Statistic::
* StatisticDiff::
* Trace::
* Traceback::

Software Packaging and Distribution

* ensurepip — Bootstrapping the pip installer::
* venv — Creation of virtual environments::
* zipapp — Manage executable Python zip archives::

ensurepip — Bootstrapping the pip installer

* Command-line interface: Command-line interface<7>.
* Module API::

venv — Creation of virtual environments

* Creating virtual environments::
* How venvs work::
* API: API<2>.
* An example of extending EnvBuilder::

zipapp — Manage executable Python zip archives

* Basic Example::
* Command-Line Interface: Command-Line Interface<4>.
* Python API::
* Examples: Examples<32>.
* Specifying the Interpreter::
* Creating Standalone Applications with zipapp::
* The Python Zip Application Archive Format::

Creating Standalone Applications with zipapp

* Caveats::

Python Runtime Services

* sys — System-specific parameters and functions::
* sys.monitoring — Execution event monitoring: sys monitoring — Execution event monitoring.
* sysconfig — Provide access to Python’s configuration information::
* builtins — Built-in objects::
* __main__ — Top-level code environment::
* warnings — Warning control::
* dataclasses — Data Classes::
* contextlib — Utilities for with-statement contexts::
* abc — Abstract Base Classes::
* atexit — Exit handlers::
* traceback — Print or retrieve a stack traceback::
* __future__ — Future statement definitions::
* gc — Garbage Collector interface::
* inspect — Inspect live objects::
* site — Site-specific configuration hook::

sys.monitoring — Execution event monitoring

* Tool identifiers::
* Events::
* Turning events on and off::
* Registering callback functions::

Tool identifiers

* Registering and using tools::

Events

* Local events::
* Ancillary events::
* Other events::
* The STOP_ITERATION event::

Turning events on and off

* Setting events globally::
* Per code object events::
* Disabling events::

Registering callback functions

* Callback function arguments::

sysconfig — Provide access to Python’s configuration information

* Configuration variables::
* Installation paths::
* User scheme::
* Home scheme::
* Prefix scheme::
* Installation path functions::
* Other functions: Other functions<3>.
* Command-line usage: Command-line usage<4>.

User scheme

* posix_user::
* nt_user::
* osx_framework_user::

Home scheme

* posix_home::

Prefix scheme

* posix_prefix::
* nt::

__main__ — Top-level code environment

* __name__ == '__main__'::
* __main__.py in Python Packages: __main__ py in Python Packages.
* import __main__::

__name__ == '__main__'

* What is the “top-level code environment”?::
* Idiomatic Usage::
* Packaging Considerations::

__main__.py in Python Packages

* Idiomatic Usage: Idiomatic Usage<2>.

warnings — Warning control

* Warning Categories::
* The Warnings Filter::
* Temporarily Suppressing Warnings::
* Testing Warnings::
* Updating Code For New Versions of Dependencies::
* Available Functions::
* Available Context Managers::

The Warnings Filter

* Repeated Warning Suppression Criteria::
* Describing Warning Filters::
* Default Warning Filter::
* Overriding the default filter::

dataclasses — Data Classes

* Module contents: Module contents<5>.
* Post-init processing::
* Class variables::
* Init-only variables::
* Frozen instances::
* Inheritance: Inheritance<2>.
* Re-ordering of keyword-only parameters in __init__(): Re-ordering of keyword-only parameters in __init__.
* Default factory functions::
* Mutable default values::
* Descriptor-typed fields::

contextlib — Utilities for with-statement contexts

* Utilities::
* Examples and Recipes: Examples and Recipes<3>.
* Single use, reusable and reentrant context managers: Single use reusable and reentrant context managers.

Examples and Recipes

* Supporting a variable number of context managers::
* Catching exceptions from __enter__ methods::
* Cleaning up in an __enter__ implementation::
* Replacing any use of try-finally and flag variables::
* Using a context manager as a function decorator::

Single use, reusable and reentrant context managers

* Reentrant context managers::
* Reusable context managers::

atexit — Exit handlers

* atexit Example::

traceback — Print or retrieve a stack traceback

* Module-Level Functions: Module-Level Functions<2>.
* TracebackException Objects::
* StackSummary Objects::
* FrameSummary Objects::
* Examples of Using the Module-Level Functions::
* Examples of Using TracebackException::

__future__ — Future statement definitions

* Module Contents: Module Contents<4>.

inspect — Inspect live objects

* Types and members::
* Retrieving source code::
* Introspecting callables with the Signature object::
* Classes and functions: Classes and functions<2>.
* The interpreter stack::
* Fetching attributes statically::
* Current State of Generators, Coroutines, and Asynchronous Generators: Current State of Generators Coroutines and Asynchronous Generators.
* Code Objects Bit Flags::
* Buffer flags::
* Command-line interface: Command-line interface<8>.

site — Site-specific configuration hook

* sitecustomize::
* usercustomize::
* Readline configuration::
* Module contents: Module contents<6>.
* Command-line interface: Command-line interface<9>.

Custom Python Interpreters

* code — Interpreter base classes::
* codeop — Compile Python code::

code — Interpreter base classes

* Interactive Interpreter Objects::
* Interactive Console Objects::

Importing Modules

* zipimport — Import modules from Zip archives::
* pkgutil — Package extension utility::
* modulefinder — Find modules used by a script::
* runpy — Locating and executing Python modules::
* importlib — The implementation of import::
* importlib.resources – Package resource reading, opening and access: importlib resources – Package resource reading opening and access.
* importlib.resources.abc – Abstract base classes for resources: importlib resources abc – Abstract base classes for resources.
* importlib.metadata – Accessing package metadata: importlib metadata – Accessing package metadata.
* The initialization of the sys.path module search path: The initialization of the sys path module search path.

zipimport — Import modules from Zip archives

* zipimporter Objects::
* Examples: Examples<33>.

modulefinder — Find modules used by a script

* Example usage of ModuleFinder::

importlib — The implementation of import

* Introduction: Introduction<12>.
* Functions: Functions<12>.
* importlib.abc – Abstract base classes related to import: importlib abc – Abstract base classes related to import.
* importlib.machinery – Importers and path hooks: importlib machinery – Importers and path hooks.
* importlib.util – Utility code for importers: importlib util – Utility code for importers.
* Examples: Examples<34>.

Examples

* Importing programmatically::
* Checking if a module can be imported::
* Importing a source file directly::
* Implementing lazy imports::
* Setting up an importer::
* Approximating importlib.import_module(): Approximating importlib import_module.

importlib.resources – Package resource reading, opening and access

* Functional API::

importlib.metadata – Accessing package metadata

* Overview: Overview<3>.
* Functional API: Functional API<2>.
* Distributions::
* Distribution Discovery::
* Extending the search algorithm::

Functional API

* Entry points::
* Distribution metadata::
* Distribution versions::
* Distribution files::
* Distribution requirements::
* Mapping import to distribution packages::

Extending the search algorithm

* Example: Example<14>.

The initialization of the sys.path module search path

* Virtual environments: Virtual environments<2>.
* _pth files::
* Embedded Python::

Python Language Services

* ast — Abstract Syntax Trees::
* symtable — Access to the compiler’s symbol tables::
* token — Constants used with Python parse trees::
* keyword — Testing for Python keywords::
* tokenize — Tokenizer for Python source::
* tabnanny — Detection of ambiguous indentation::
* pyclbr — Python module browser support::
* py_compile — Compile Python source files::
* compileall — Byte-compile Python libraries::
* dis — Disassembler for Python bytecode::
* pickletools — Tools for pickle developers::

ast — Abstract Syntax Trees

* Abstract Grammar::
* Node classes::
* ast Helpers::
* Compiler Flags::
* Command-Line Usage: Command-Line Usage<4>.

Node classes

* Root nodes::
* Literals: Literals<3>.
* Variables::
* Expressions: Expressions<2>.
* Statements::
* Control flow::
* Pattern matching::
* Type annotations::
* Type parameters::
* Function and class definitions::
* Async and await::

Expressions

* Subscripting::
* Comprehensions::

Statements

* Imports::

symtable — Access to the compiler’s symbol tables

* Generating Symbol Tables::
* Examining Symbol Tables::
* Command-Line Usage: Command-Line Usage<5>.

tokenize — Tokenizer for Python source

* Tokenizing Input::
* Command-Line Usage: Command-Line Usage<6>.
* Examples: Examples<35>.

pyclbr — Python module browser support

* Function Objects::
* Class Objects: Class Objects<2>.

py_compile — Compile Python source files

* Command-Line Interface: Command-Line Interface<5>.

compileall — Byte-compile Python libraries

* Command-line use::
* Public functions::

dis — Disassembler for Python bytecode

* Command-line interface: Command-line interface<10>.
* Bytecode analysis::
* Analysis functions::
* Python Bytecode Instructions::
* Opcode collections::

pickletools — Tools for pickle developers

* Command line usage::
* Programmatic Interface: Programmatic Interface<2>.

Command line usage

* Command line options: Command line options<2>.

MS Windows Specific Services

* msvcrt — Useful routines from the MS VC++ runtime::
* winreg — Windows registry access::
* winsound — Sound-playing interface for Windows::

msvcrt — Useful routines from the MS VC++ runtime

* File Operations::
* Console I/O::
* Other Functions::

winreg — Windows registry access

* Functions: Functions<13>.
* Constants: Constants<10>.
* Registry Handle Objects::

Constants

* HKEY_* Constants::
* Access Rights::
* Value Types::

Access Rights

* 64-bit Specific::

Unix-specific services

* shlex — Simple lexical analysis::
* posix — The most common POSIX system calls::
* pwd — The password database::
* grp — The group database::
* termios — POSIX style tty control::
* tty — Terminal control functions::
* pty — Pseudo-terminal utilities::
* fcntl — The fcntl and ioctl system calls::
* resource — Resource usage information::
* syslog — Unix syslog library routines::

shlex — Simple lexical analysis

* shlex Objects::
* Parsing Rules::
* Improved Compatibility with Shells::

posix — The most common POSIX system calls

* Large File Support::
* Notable Module Contents::

termios — POSIX style tty control

* Example: Example<15>.

pty — Pseudo-terminal utilities

* Example: Example<16>.

resource — Resource usage information

* Resource Limits::
* Resource Usage::

syslog — Unix syslog library routines

* Examples: Examples<36>.

Examples

* Simple example::

Superseded Modules

* getopt — C-style parser for command line options::

Removed Modules

* aifc — Read and write AIFF and AIFC files::
* asynchat — Asynchronous socket command/response handler::
* asyncore — Asynchronous socket handler::
* audioop — Manipulate raw audio data::
* cgi — Common Gateway Interface support::
* cgitb — Traceback manager for CGI scripts::
* chunk — Read IFF chunked data::
* crypt — Function to check Unix passwords::
* distutils — Building and installing Python modules::
* imghdr — Determine the type of an image::
* imp — Access the import internals::
* mailcap — Mailcap file handling::
* msilib — Read and write Microsoft Installer files::
* nis — Interface to Sun’s NIS (Yellow Pages): nis — Interface to Sun’s NIS Yellow Pages.
* nntplib — NNTP protocol client::
* ossaudiodev — Access to OSS-compatible audio devices::
* pipes — Interface to shell pipelines::
* smtpd — SMTP Server::
* sndhdr — Determine type of sound file::
* spwd — The shadow password database::
* sunau — Read and write Sun AU files::
* telnetlib — Telnet client::
* uu — Encode and decode uuencode files::
* xdrlib — Encode and decode XDR data::

Extending and Embedding the Python Interpreter

* Recommended third party tools::
* Creating extensions without third party tools::
* Embedding the CPython runtime in a larger application::

Creating extensions without third party tools

* Extending Python with C or C++::
* Defining Extension Types; Tutorial: Defining Extension Types Tutorial.
* Defining Extension Types; Assorted Topics: Defining Extension Types Assorted Topics.
* Building C and C++ Extensions::
* Building C and C++ Extensions on Windows::

Extending Python with C or C++

* A Simple Example::
* Intermezzo; Errors and Exceptions: Intermezzo Errors and Exceptions.
* Back to the Example::
* The Module’s Method Table and Initialization Function::
* Compilation and Linkage::
* Calling Python Functions from C::
* Extracting Parameters in Extension Functions::
* Keyword Parameters for Extension Functions::
* Building Arbitrary Values::
* Reference Counts::
* Writing Extensions in C++::
* Providing a C API for an Extension Module::

Reference Counts

* Reference Counting in Python::
* Ownership Rules::
* Thin Ice::
* NULL Pointers::

Defining Extension Types: Tutorial

* The Basics::
* Adding data and methods to the Basic example::
* Providing finer control over data attributes::
* Supporting cyclic garbage collection::
* Subclassing other types::

Defining Extension Types: Assorted Topics

* Finalization and De-allocation::
* Object Presentation::
* Attribute Management::
* Object Comparison::
* Abstract Protocol Support::
* Weak Reference Support::
* More Suggestions::

Attribute Management

* Generic Attribute Management::
* Type-specific Attribute Management::

Building C and C++ Extensions

* Building C and C++ Extensions with setuptools::

Building C and C++ Extensions on Windows

* A Cookbook Approach::
* Differences Between Unix and Windows::
* Using DLLs in Practice::

Embedding the CPython runtime in a larger application

* Embedding Python in Another Application::

Embedding Python in Another Application

* Very High Level Embedding::
* Beyond Very High Level Embedding; An overview: Beyond Very High Level Embedding An overview.
* Pure Embedding::
* Extending Embedded Python::
* Embedding Python in C++::
* Compiling and Linking under Unix-like systems::

Python/C API Reference Manual

* Introduction: Introduction<13>.
* C API Stability::
* The Very High Level Layer::
* Reference Counting::
* Exception Handling::
* Utilities: Utilities<2>.
* Abstract Objects Layer::
* Concrete Objects Layer::
* Initialization, Finalization, and Threads: Initialization Finalization and Threads.
* Python Initialization Configuration::
* Memory Management::
* Object Implementation Support::
* API and ABI Versioning::
* Monitoring C API::
* Generating Execution Events::

Introduction

* Coding standards::
* Include Files::
* Useful macros::
* Objects, Types and Reference Counts: Objects Types and Reference Counts.
* Exceptions: Exceptions<21>.
* Embedding Python: Embedding Python<2>.
* Debugging Builds::
* Recommended third party tools: Recommended third party tools<2>.

Objects, Types and Reference Counts

* Reference Counts: Reference Counts<2>.
* Types::

Reference Counts

* Reference Count Details::

C API Stability

* Unstable C API::
* Stable Application Binary Interface::
* Platform Considerations::
* Contents of Limited API::

Stable Application Binary Interface

* Limited C API::
* Stable ABI::
* Limited API Scope and Performance::
* Limited API Caveats::

The Very High Level Layer

* Available start symbols::
* Stack Effects::

Exception Handling

* Printing and clearing::
* Raising exceptions::
* Issuing warnings::
* Querying the error indicator::
* Signal Handling: Signal Handling<2>.
* Exception Classes::
* Exception Objects::
* Unicode Exception Objects::
* Recursion Control::
* Exception and warning types::
* Tracebacks::

Exception and warning types

* Exception types::
* OSError aliases::
* Warning types::

Utilities

* Operating System Utilities::
* System Functions::
* Process Control::
* Importing Modules: Importing Modules<2>.
* Data marshalling support::
* Parsing arguments and building values::
* String conversion and formatting::
* Character classification and conversion::
* PyHash API::
* Reflection::
* Codec registry and support functions::
* PyTime C API::
* Support for Perf Maps::

Parsing arguments and building values

* Parsing arguments: Parsing arguments<2>.
* Building values::

Parsing arguments

* Strings and buffers::
* Numbers: Numbers<2>.
* Other objects::
* API Functions::

Codec registry and support functions

* Codec lookup API::
* Registry API for Unicode encoding error handlers::
* Codec utility variables::

PyTime C API

* Types: Types<2>.
* Clock Functions::
* Raw Clock Functions::
* Conversion functions::

Abstract Objects Layer

* Object Protocol::
* Call Protocol::
* Number Protocol::
* Sequence Protocol::
* Mapping Protocol::
* Iterator Protocol::
* Buffer Protocol::

Call Protocol

* The tp_call Protocol::
* The Vectorcall Protocol::
* Object Calling API::
* Call Support API::

The Vectorcall Protocol

* Recursion Control: Recursion Control<2>.
* Vectorcall Support API::

Buffer Protocol

* Buffer structure::
* Buffer request types::
* Complex arrays::
* Buffer-related functions::

Buffer request types

* request-independent fields::
* readonly, format: readonly format.
* shape, strides, suboffsets: shape strides suboffsets.
* contiguity requests::
* compound requests::

Complex arrays

* NumPy-style; shape and strides: NumPy-style shape and strides.
* PIL-style; shape, strides and suboffsets: PIL-style shape strides and suboffsets.

Concrete Objects Layer

* Fundamental Objects::
* Numeric Objects::
* Sequence Objects::
* Container Objects::
* Function Objects: Function Objects<2>.
* Other Objects::
* C API for extension modules::

Fundamental Objects

* Type Objects: Type Objects<2>.
* The None Object::

Type Objects

* Creating Heap-Allocated Types::

Numeric Objects

* Integer Objects::
* Boolean Objects::
* Floating-Point Objects::
* Complex Number Objects::

Floating-Point Objects

* Pack and Unpack functions::

Pack and Unpack functions

* Pack functions::
* Unpack functions::

Complex Number Objects

* Complex Numbers as C Structures::
* Complex Numbers as Python Objects::

Sequence Objects

* Bytes Objects: Bytes Objects<2>.
* Byte Array Objects::
* Unicode Objects and Codecs::
* Tuple Objects::
* Struct Sequence Objects::
* List Objects::

Byte Array Objects

* Type check macros::
* Direct API functions::
* Macros::

Unicode Objects and Codecs

* Unicode Objects::
* Built-in Codecs::
* Methods and Slot Functions::

Unicode Objects

* Unicode Type::
* Unicode Character Properties::
* Creating and accessing Unicode strings::
* Locale Encoding::
* File System Encoding::
* wchar_t Support::

Built-in Codecs

* Generic Codecs::
* UTF-8 Codecs::
* UTF-32 Codecs::
* UTF-16 Codecs::
* UTF-7 Codecs::
* Unicode-Escape Codecs::
* Raw-Unicode-Escape Codecs::
* Latin-1 Codecs::
* ASCII Codecs::
* Character Map Codecs::
* MBCS codecs for Windows::

Container Objects

* Dictionary Objects::
* Set Objects::

Dictionary Objects

* Dictionary View Objects::
* Ordered Dictionaries::

Function Objects

* Function Objects: Function Objects<3>.
* Instance Method Objects::
* Method Objects: Method Objects<2>.
* Cell Objects::
* Code Objects: Code Objects<2>.
* Code Object Flags::
* Extra information::

Other Objects

* File Objects::
* Module Objects::
* Iterator Objects::
* Descriptor Objects::
* Slice Objects::
* MemoryView objects::
* Pickle buffer objects::
* Weak Reference Objects: Weak Reference Objects<2>.
* Capsules: Capsules<2>.
* Frame Objects::
* Generator Objects::
* Coroutine Objects: Coroutine Objects<2>.
* Context Variables Objects::
* Objects for Type Hinting::

Module Objects

* Initializing C modules::
* Module lookup::

Initializing C modules

* Single-phase initialization::
* Multi-phase initialization::
* Low-level module creation functions::
* Support functions::

Iterator Objects

* Range Objects::
* Builtin Iterator Types::
* Other Iterator Objects::

Descriptor Objects

* Built-in descriptors::

Slice Objects

* Ellipsis Object::

Frame Objects

* Frame Locals Proxies::
* Legacy Local Variable APIs::
* Internal Frames::

Generator Objects

* Asynchronous Generator Objects::

C API for extension modules

* Curses C API::
* Internal data::
* DateTime Objects: DateTime Objects<2>.
* Internal data: Internal data<2>.

Initialization, Finalization, and Threads

* Before Python Initialization::
* Global configuration variables::
* Initializing and finalizing the interpreter::
* Process-wide parameters::
* Thread State and the Global Interpreter Lock::
* Sub-interpreter support::
* Asynchronous Notifications::
* Profiling and Tracing::
* Reference tracing::
* Advanced Debugger Support::
* Thread Local Storage Support::
* Synchronization Primitives: Synchronization Primitives<2>.
* Operating System Thread APIs::

Thread State and the Global Interpreter Lock

* Releasing the GIL from extension code::
* Non-Python created threads::
* Cautions about fork(): Cautions about fork.
* Cautions regarding runtime finalization::
* High-level API::
* Low-level API::

Sub-interpreter support

* A Per-Interpreter GIL::
* Bugs and caveats::

Thread Local Storage Support

* Thread Specific Storage (TSS) API: Thread Specific Storage TSS API.
* Thread Local Storage (TLS) API: Thread Local Storage TLS API.

Thread Specific Storage (TSS) API

* Dynamic Allocation::
* Methods: Methods<2>.

Synchronization Primitives

* Python Critical Section API::
* Legacy Locking APIs::

Python Initialization Configuration

* Example: Example<17>.
* PyWideStringList::
* PyStatus::
* PyPreConfig::
* Preinitialize Python with PyPreConfig::
* PyConfig::
* Initialization with PyConfig::
* Isolated Configuration::
* Python Configuration::
* Python Path Configuration::
* Py_GetArgcArgv(): Py_GetArgcArgv.
* Multi-Phase Initialization Private Provisional API::

Memory Management

* Overview: Overview<4>.
* Allocator Domains::
* Raw Memory Interface::
* Memory Interface::
* Object allocators::
* Default Memory Allocators::
* Customize Memory Allocators::
* Debug hooks on the Python memory allocators::
* The pymalloc allocator::
* The mimalloc allocator::
* tracemalloc C API::
* Examples: Examples<37>.

Memory Interface

* Deprecated aliases: Deprecated aliases<2>.

The pymalloc allocator

* Customize pymalloc Arena Allocator::

Object Implementation Support

* Allocating Objects on the Heap::
* Common Object Structures::
* Type Object Structures::
* Supporting Cyclic Garbage Collection::

Allocating Objects on the Heap

* Deprecated aliases: Deprecated aliases<3>.

Common Object Structures

* Base object types and macros::
* Implementing functions and methods::
* Accessing attributes of extension types::

Accessing attributes of extension types

* Member flags::
* Member types::
* Defining Getters and Setters::

Type Object Structures

* Quick Reference::
* PyTypeObject Definition::
* PyObject Slots::
* PyVarObject Slots::
* PyTypeObject Slots::
* Static Types::
* Heap Types::
* Number Object Structures::
* Mapping Object Structures::
* Sequence Object Structures::
* Buffer Object Structures::
* Async Object Structures::
* Slot Type typedefs::
* Examples: Examples<38>.

Quick Reference

* “tp slots”::
* sub-slots::
* slot typedefs::

Supporting Cyclic Garbage Collection

* Controlling the Garbage Collector State::
* Querying Garbage Collector State::

Generating Execution Events

* Managing the Monitoring State::

Installing Python modules

* Key terms::
* Basic usage::
* How do I …?::
* Common installation issues::

How do I …?

* … install packages just for the current user?::
* … install scientific Python packages?::
* … work with multiple versions of Python installed in parallel?::

Common installation issues

* Installing into the system Python on Linux::
* Pip not installed::
* Installing binary extensions::

Python HOWTOs

* A Conceptual Overview of asyncio::
* Porting Extension Modules to Python 3::
* Curses Programming with Python::
* Descriptor Guide::
* Debugging C API extensions and CPython Internals with GDB::
* Enum HOWTO::
* Functional Programming HOWTO::
* Logging HOWTO::
* Logging Cookbook::
* Regular expression HOWTO::
* Socket Programming HOWTO::
* Sorting Techniques::
* Unicode HOWTO::
* HOWTO Fetch Internet Resources Using The urllib Package::
* An introduction to the ipaddress module::
* Instrumenting CPython with DTrace and SystemTap::
* Python support for the Linux perf profiler::
* Annotations Best Practices::
* Isolating Extension Modules::
* timer file descriptor HOWTO::
* The Python 2.3 Method Resolution Order: The Python 2 3 Method Resolution Order.
* Python experimental support for free threading::
* C API Extension Support for Free Threading::

A Conceptual Overview of asyncio

* A conceptual overview part 1; the high-level: A conceptual overview part 1 the high-level.
* A conceptual overview part 2; the nuts and bolts: A conceptual overview part 2 the nuts and bolts.

A conceptual overview part 1: the high-level

* Event Loop::
* Asynchronous functions and coroutines::
* Tasks: Tasks<2>.
* await::

A conceptual overview part 2: the nuts and bolts

* The inner workings of coroutines::
* Futures: Futures<2>.
* A homemade asyncio.sleep: A homemade asyncio sleep.

Curses Programming with Python

* What is curses?::
* Starting and ending a curses application::
* Windows and Pads::
* Displaying Text::
* User Input::
* For More Information::

What is curses?

* The Python curses module::

Displaying Text

* Attributes and Color::

Descriptor Guide

* Primer::
* Complete Practical Example::
* Technical Tutorial::
* Pure Python Equivalents::

Primer

* Simple example; A descriptor that returns a constant: Simple example A descriptor that returns a constant.
* Dynamic lookups::
* Managed attributes::
* Customized names::
* Closing thoughts::

Complete Practical Example

* Validator class::
* Custom validators::
* Practical application::

Technical Tutorial

* Abstract::
* Definition and introduction::
* Descriptor protocol::
* Overview of descriptor invocation::
* Invocation from an instance::
* Invocation from a class::
* Invocation from super::
* Summary of invocation logic::
* Automatic name notification::
* ORM example::

Pure Python Equivalents

* Properties::
* Functions and methods::
* Kinds of methods::
* Static methods::
* Class methods::
* Member objects and __slots__::

Debugging C API extensions and CPython Internals with GDB

* Prerequisites::
* Using the Debug build and Development mode::
* Using the python-gdb extension::
* Use with GDB commands::

Prerequisites

* Setup with Python built from source::
* Setup for Python from a Linux distro::

Using the python-gdb extension

* Pretty-printers::
* py-list::
* py-up and py-down::
* py-bt::
* py-print::
* py-locals::

Enum HOWTO

* Programmatic access to enumeration members and their attributes::
* Duplicating enum members and values::
* Ensuring unique enumeration values::
* Using automatic values::
* Iteration: Iteration<2>.
* Comparisons: Comparisons<3>.
* Allowed members and attributes of enumerations::
* Restricted Enum subclassing::
* Dataclass support::
* Pickling::
* Functional API: Functional API<3>.
* Derived Enumerations::
* When to use __new__() vs. __init__(): When to use __new__ vs __init__.
* Finer Points::
* How are Enums and Flags different?::
* Enum Cookbook::
* Subclassing EnumType::

Derived Enumerations

* IntEnum::
* StrEnum::
* IntFlag::
* Flag::
* Others: Others<2>.

Finer Points

* Supported __dunder__ and _sunder_ names::
* _Private__names::
* Enum member type::
* Creating members that are mixed with other data types::
* Boolean value of Enum classes and members::
* Enum classes with methods::
* Combining members of Flag::
* Flag and IntFlag minutia::

How are Enums and Flags different?

* Enum Classes::
* Flag Classes::
* Enum Members (aka instances): Enum Members aka instances.
* Flag Members::

Enum Cookbook

* Omitting values::
* OrderedEnum::
* DuplicateFreeEnum::
* MultiValueEnum::
* Planet::
* TimePeriod::

Omitting values

* Using auto::
* Using object::
* Using a descriptive string::
* Using a custom __new__(): Using a custom __new__.

Functional Programming HOWTO

* Introduction: Introduction<14>.
* Iterators: Iterators<2>.
* Generator expressions and list comprehensions::
* Generators: Generators<2>.
* Built-in functions: Built-in functions<2>.
* The itertools module::
* The functools module::
* Small functions and the lambda expression::
* Revision History and Acknowledgements::
* References: References<2>.

Introduction

* Formal provability::
* Modularity::
* Ease of debugging and testing::
* Composability::

Iterators

* Data Types That Support Iterators::

Generators

* Passing values into a generator::

The itertools module

* Creating new iterators::
* Calling functions on elements::
* Selecting elements::
* Combinatoric functions::
* Grouping elements::

The functools module

* The operator module::

References

* General::
* Python-specific::
* Python documentation::

Logging HOWTO

* Basic Logging Tutorial::
* Advanced Logging Tutorial::
* Logging Levels: Logging Levels<2>.
* Useful Handlers::
* Exceptions raised during logging::
* Using arbitrary objects as messages::
* Optimization::
* Other resources::

Basic Logging Tutorial

* When to use logging::
* A simple example::
* Logging to a file::
* Logging variable data::
* Changing the format of displayed messages::
* Displaying the date/time in messages::
* Next Steps::

Advanced Logging Tutorial

* Logging Flow::
* Loggers::
* Handlers::
* Formatters::
* Configuring Logging::
* What happens if no configuration is provided::
* Configuring Logging for a Library::

Logging Levels

* Custom Levels::

Logging Cookbook

* Using logging in multiple modules::
* Logging from multiple threads::
* Multiple handlers and formatters::
* Logging to multiple destinations::
* Custom handling of levels::
* Configuration server example::
* Dealing with handlers that block::
* Sending and receiving logging events across a network::
* Adding contextual information to your logging output::
* Use of contextvars::
* Imparting contextual information in handlers::
* Logging to a single file from multiple processes::
* Using file rotation::
* Use of alternative formatting styles::
* Customizing LogRecord::
* Subclassing QueueHandler and QueueListener- a ZeroMQ example::
* Subclassing QueueHandler and QueueListener- a pynng example::
* An example dictionary-based configuration::
* Using a rotator and namer to customize log rotation processing::
* A more elaborate multiprocessing example::
* Inserting a BOM into messages sent to a SysLogHandler::
* Implementing structured logging::
* Customizing handlers with dictConfig(): Customizing handlers with dictConfig.
* Using particular formatting styles throughout your application::
* Configuring filters with dictConfig(): Configuring filters with dictConfig.
* Customized exception formatting::
* Speaking logging messages::
* Buffering logging messages and outputting them conditionally::
* Sending logging messages to email, with buffering: Sending logging messages to email with buffering.
* Formatting times using UTC (GMT) via configuration: Formatting times using UTC GMT via configuration.
* Using a context manager for selective logging::
* A CLI application starter template::
* A Qt GUI for logging::
* Logging to syslog with RFC5424 support::
* How to treat a logger like an output stream::
* How to uniformly handle newlines in logging output::
* Patterns to avoid::
* Other resources: Other resources<2>.

Sending and receiving logging events across a network

* Running a logging socket listener in production::

Adding contextual information to your logging output

* Using LoggerAdapters to impart contextual information::
* Using Filters to impart contextual information::

Using LoggerAdapters to impart contextual information

* Using objects other than dicts to pass contextual information::

Logging to a single file from multiple processes

* Using concurrent.futures.ProcessPoolExecutor: Using concurrent futures ProcessPoolExecutor.
* Deploying web applications using Gunicorn and uWSGI::

Subclassing QueueHandler and QueueListener- a ZeroMQ example

* Subclass QueueHandler::
* Subclass QueueListener::

Subclassing QueueHandler and QueueListener- a pynng example

* Subclass QueueListener: Subclass QueueListener<2>.
* Subclass QueueHandler: Subclass QueueHandler<2>.

Using particular formatting styles throughout your application

* Using LogRecord factories::
* Using custom message objects::

Patterns to avoid

* Opening the same log file multiple times::
* Using loggers as attributes in a class or passing them as parameters::
* Adding handlers other than NullHandler to a logger in a library::
* Creating a lot of loggers::

Regular expression HOWTO

* Introduction: Introduction<15>.
* Simple patterns::
* Using regular expressions::
* More pattern power::
* Modifying strings::
* Common problems::
* Feedback::

Simple patterns

* Matching characters::
* Repeating things::

Using regular expressions

* Compiling regular expressions::
* The backslash plague::
* Performing matches::
* Module-level functions::
* Compilation flags::

More pattern power

* More metacharacters::
* Grouping::
* Non-capturing and named groups::
* Lookahead assertions::

Modifying strings

* Splitting strings::
* Search and replace::

Common problems

* Use string methods::
* match() versus search(): match versus search.
* Greedy versus non-greedy::
* Using re.VERBOSE: Using re VERBOSE.

Socket Programming HOWTO

* Sockets::
* Creating a Socket::
* Using a Socket::
* Disconnecting::
* Non-blocking Sockets::

Sockets

* History::

Creating a Socket

* IPC::

Using a Socket

* Binary Data::

Disconnecting

* When Sockets Die::

Sorting Techniques

* Sorting Basics::
* Key Functions::
* Operator Module Functions and Partial Function Evaluation::
* Ascending and Descending::
* Sort Stability and Complex Sorts::
* Decorate-Sort-Undecorate::
* Comparison Functions::
* Odds and Ends: Odds and Ends<2>.
* Partial Sorts::

Unicode HOWTO

* Introduction to Unicode::
* Python’s Unicode Support::
* Reading and Writing Unicode Data::
* Acknowledgements: Acknowledgements<10>.

Introduction to Unicode

* Definitions::
* Encodings::
* References: References<3>.

Python’s Unicode Support

* The String Type::
* Converting to Bytes::
* Unicode Literals in Python Source Code::
* Unicode Properties::
* Comparing Strings::
* Unicode Regular Expressions::
* References: References<4>.

Reading and Writing Unicode Data

* Unicode filenames::
* Tips for Writing Unicode-aware Programs::
* References: References<5>.

Tips for Writing Unicode-aware Programs

* Converting Between File Encodings::
* Files in an Unknown Encoding::

HOWTO Fetch Internet Resources Using The urllib Package

* Introduction: Introduction<16>.
* Fetching URLs::
* Handling Exceptions: Handling Exceptions<2>.
* info and geturl::
* Openers and Handlers::
* Basic Authentication::
* Proxies::
* Sockets and Layers::
* Footnotes::

Fetching URLs

* Data::
* Headers::

Handling Exceptions

* URLError::
* HTTPError::
* Wrapping it Up::

HTTPError

* Error Codes::

Wrapping it Up

* Number 1::
* Number 2::

An introduction to the ipaddress module

* Creating Address/Network/Interface objects::
* Inspecting Address/Network/Interface Objects::
* Networks as lists of Addresses::
* Comparisons: Comparisons<4>.
* Using IP Addresses with other modules::
* Getting more detail when instance creation fails::

Creating Address/Network/Interface objects

* A Note on IP Versions::
* IP Host Addresses::
* Defining Networks::
* Host Interfaces::

Instrumenting CPython with DTrace and SystemTap

* Enabling the static markers::
* Static DTrace probes::
* Static SystemTap markers::
* Available static markers::
* SystemTap Tapsets::
* Examples: Examples<39>.

Available static markers

* C Entry Points::
* C Probing Checks::

Python support for the Linux perf profiler

* How to enable perf profiling support::
* How to obtain the best results::
* How to work without frame pointers::

Annotations Best Practices

* Accessing The Annotations Dict Of An Object In Python 3.10 And Newer: Accessing The Annotations Dict Of An Object In Python 3 10 And Newer.
* Accessing The Annotations Dict Of An Object In Python 3.9 And Older: Accessing The Annotations Dict Of An Object In Python 3 9 And Older.
* Manually Un-Stringizing Stringized Annotations::
* Best Practices For __annotations__ In Any Python Version::
* __annotations__ Quirks::

Isolating Extension Modules

* Who should read this::
* Background: Background<2>.
* Making Modules Safe with Multiple Interpreters::
* Heap Types: Heap Types<2>.
* Open Issues::

Background

* Enter Per-Module State::
* Isolated Module Objects::
* Surprising Edge Cases::

Making Modules Safe with Multiple Interpreters

* Managing Global State::
* Managing Per-Module State::
* Opt-Out; Limiting to One Module Object per Process: Opt-Out Limiting to One Module Object per Process.
* Module State Access from Functions::

Heap Types

* Changing Static Types to Heap Types::
* Defining Heap Types::
* Garbage-Collection Protocol::
* Module State Access from Classes::
* Module State Access from Regular Methods::
* Module State Access from Slot Methods, Getters and Setters: Module State Access from Slot Methods Getters and Setters.
* Lifetime of the Module State::

Garbage-Collection Protocol

* tp_traverse in Python 3.8 and lower: tp_traverse in Python 3 8 and lower.
* Delegating tp_traverse::
* Defining tp_dealloc::
* Not overriding tp_free::
* Avoiding PyObject_New::

Open Issues

* Per-Class Scope::
* Lossless Conversion to Heap Types::

timer file descriptor HOWTO

* Examples: Examples<40>.

The Python 2.3 Method Resolution Order

* The beginning::
* The C3 Method Resolution Order::
* Examples: Examples<41>.
* Bad Method Resolution Orders::
* The end::
* Resources::

Python experimental support for free threading

* Installation::
* Identifying free-threaded Python::
* The global interpreter lock in free-threaded Python::
* Thread safety::
* Known limitations::

Known limitations

* Immortalization::
* Frame objects: Frame objects<2>.
* Iterators: Iterators<3>.
* Single-threaded performance::

C API Extension Support for Free Threading

* Identifying the Free-Threaded Build in C::
* Module Initialization::
* General API Guidelines::
* Borrowed References::
* Memory Allocation APIs::
* Thread State and GIL APIs::
* Protecting Internal Extension State::
* Building Extensions for the Free-Threaded Build::

Module Initialization

* Multi-Phase Initialization::
* Single-Phase Initialization::

General API Guidelines

* Container Thread Safety::

Container Thread Safety

* PyDict_Next::

Building Extensions for the Free-Threaded Build

* Limited C API and Stable ABI::
* Windows: Windows<83>.

Python Frequently Asked Questions

* General Python FAQ::
* Programming FAQ::
* Design and History FAQ::
* Library and Extension FAQ::
* Extending/Embedding FAQ::
* Python on Windows FAQ::
* Graphic User Interface FAQ::
* “Why is Python Installed on my Computer?” FAQ::

General Python FAQ

* General Information::
* Python in the real world::

General Information

* What is Python?::
* What is the Python Software Foundation?::
* Are there copyright restrictions on the use of Python?::
* Why was Python created in the first place?::
* What is Python good for?::
* How does the Python version numbering scheme work?::
* How do I obtain a copy of the Python source?::
* How do I get documentation on Python?::
* I’ve never programmed before. Is there a Python tutorial?: I’ve never programmed before Is there a Python tutorial?.
* Is there a newsgroup or mailing list devoted to Python?::
* How do I get a beta test version of Python?::
* How do I submit bug reports and patches for Python?::
* Are there any published articles about Python that I can reference?::
* Are there any books on Python?::
* Where in the world is www.python.org located?: Where in the world is www python org located?.
* Why is it called Python?::
* Do I have to like “Monty Python’s Flying Circus”?::

Python in the real world

* How stable is Python?::
* How many people are using Python?::
* Have any significant projects been done in Python?::
* What new developments are expected for Python in the future?::
* Is it reasonable to propose incompatible changes to Python?::
* Is Python a good language for beginning programmers?::

Programming FAQ

* General questions::
* Core language::
* Numbers and strings::
* Performance: Performance<4>.
* Sequences (tuples/lists): Sequences tuples/lists.
* Objects::
* Modules: Modules<5>.

General questions

* Is there a source code-level debugger with breakpoints and single-stepping?::
* Are there tools to help find bugs or perform static analysis?::
* How can I create a stand-alone binary from a Python script?::
* Are there coding standards or a style guide for Python programs?::

Core language

* Why am I getting an UnboundLocalError when the variable has a value?::
* What are the rules for local and global variables in Python?::
* Why do lambdas defined in a loop with different values all return the same result?::
* How do I share global variables across modules?::
* What are the “best practices” for using import in a module?::
* Why are default values shared between objects?::
* How can I pass optional or keyword parameters from one function to another?::
* What is the difference between arguments and parameters?::
* Why did changing list ‘y’ also change list ‘x’?::
* How do I write a function with output parameters (call by reference)?: How do I write a function with output parameters call by reference ?.
* How do you make a higher order function in Python?::
* How do I copy an object in Python?::
* How can I find the methods or attributes of an object?::
* How can my code discover the name of an object?::
* What’s up with the comma operator’s precedence?::
* Is there an equivalent of C’s “?;” ternary operator?: Is there an equivalent of C’s “? ” ternary operator?.
* Is it possible to write obfuscated one-liners in Python?::
* What does the slash(/) in the parameter list of a function mean?: What does the slash / in the parameter list of a function mean?.

Numbers and strings

* How do I specify hexadecimal and octal integers?::
* Why does -22 // 10 return -3?::
* How do I get int literal attribute instead of SyntaxError?::
* How do I convert a string to a number?::
* How do I convert a number to a string?::
* How do I modify a string in place?::
* How do I use strings to call functions/methods?::
* Is there an equivalent to Perl’s chomp() for removing trailing newlines from strings?: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?.
* Is there a scanf() or sscanf() equivalent?: Is there a scanf or sscanf equivalent?.
* What does UnicodeDecodeError or UnicodeEncodeError error mean?::
* Can I end a raw string with an odd number of backslashes?::

Performance

* My program is too slow. How do I speed it up?: My program is too slow How do I speed it up?.
* What is the most efficient way to concatenate many strings together?::

Sequences (tuples/lists)

* How do I convert between tuples and lists?::
* What’s a negative index?::
* How do I iterate over a sequence in reverse order?::
* How do you remove duplicates from a list?::
* How do you remove multiple items from a list?::
* How do you make an array in Python?::
* How do I create a multidimensional list?::
* How do I apply a method or function to a sequence of objects?::
* Why does a_tuple[i] += [‘item’] raise an exception when the addition works?::
* I want to do a complicated sort; can you do a Schwartzian Transform in Python?: I want to do a complicated sort can you do a Schwartzian Transform in Python?.
* How can I sort one list by values from another list?::

Objects

* What is a class?::
* What is a method?::
* What is self?::
* How do I check if an object is an instance of a given class or of a subclass of it?::
* What is delegation?::
* How do I call a method defined in a base class from a derived class that extends it?::
* How can I organize my code to make it easier to change the base class?::
* How do I create static class data and static class methods?::
* How can I overload constructors (or methods) in Python?: How can I overload constructors or methods in Python?.
* I try to use __spam and I get an error about _SomeClassName__spam.: I try to use __spam and I get an error about _SomeClassName__spam.
* My class defines __del__ but it is not called when I delete the object.: My class defines __del__ but it is not called when I delete the object.
* How do I get a list of all instances of a given class?::
* Why does the result of id() appear to be not unique?: Why does the result of id appear to be not unique?.
* When can I rely on identity tests with the is operator?::
* How can a subclass control what data is stored in an immutable instance?::
* How do I cache method calls?::

Modules

* How do I create a .pyc file?: How do I create a pyc file?.
* How do I find the current module name?::
* How can I have modules that mutually import each other?::
* __import__(‘x.y.z’) returns <module ‘x’>; how do I get z?: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?.
* When I edit an imported module and reimport it, the changes don’t show up. Why does this happen?: When I edit an imported module and reimport it the changes don’t show up Why does this happen?.

Design and History FAQ

* Why does Python use indentation for grouping of statements?::
* Why am I getting strange results with simple arithmetic operations?::
* Why are floating-point calculations so inaccurate?::
* Why are Python strings immutable?::
* Why must ‘self’ be used explicitly in method definitions and calls?::
* Why can’t I use an assignment in an expression?::
* Why does Python use methods for some functionality (e.g. list.index()) but functions for other (e.g. len(list))?: Why does Python use methods for some functionality e g list index but functions for other e g len list ?.
* Why is join() a string method instead of a list or tuple method?: Why is join a string method instead of a list or tuple method?.
* How fast are exceptions?::
* Why isn’t there a switch or case statement in Python?::
* Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?::
* Why can’t lambda expressions contain statements?::
* Can Python be compiled to machine code, C or some other language?: Can Python be compiled to machine code C or some other language?.
* How does Python manage memory?::
* Why doesn’t CPython use a more traditional garbage collection scheme?::
* Why isn’t all memory freed when CPython exits?::
* Why are there separate tuple and list data types?::
* How are lists implemented in CPython?::
* How are dictionaries implemented in CPython?::
* Why must dictionary keys be immutable?::
* Why doesn’t list.sort() return the sorted list?: Why doesn’t list sort return the sorted list?.
* How do you specify and enforce an interface spec in Python?::
* Why is there no goto?::
* Why can’t raw strings (r-strings) end with a backslash?: Why can’t raw strings r-strings end with a backslash?.
* Why doesn’t Python have a “with” statement for attribute assignments?::
* Why don’t generators support the with statement?::
* Why are colons required for the if/while/def/class statements?::
* Why does Python allow commas at the end of lists and tuples?::

Library and Extension FAQ

* General Library Questions::
* Common tasks::
* Threads::
* Input and Output: Input and Output<2>.
* Network/Internet Programming::
* Databases::
* Mathematics and Numerics::

General Library Questions

* How do I find a module or application to perform task X?::
* Where is the math.py (socket.py, regex.py, etc.) source file?: Where is the math py socket py regex py etc source file?.
* How do I make a Python script executable on Unix?::
* Is there a curses/termcap package for Python?::
* Is there an equivalent to C’s onexit() in Python?: Is there an equivalent to C’s onexit in Python?.
* Why don’t my signal handlers work?::

Common tasks

* How do I test a Python program or component?::
* How do I create documentation from doc strings?::
* How do I get a single keypress at a time?::

Threads

* How do I program using threads?::
* None of my threads seem to run; why?: None of my threads seem to run why?.
* How do I parcel out work among a bunch of worker threads?::
* What kinds of global value mutation are thread-safe?::
* Can’t we get rid of the Global Interpreter Lock?::

Input and Output

* How do I delete a file? (And other file questions…): How do I delete a file? And other file questions….
* How do I copy a file?::
* How do I read (or write) binary data?: How do I read or write binary data?.
* I can’t seem to use os.read() on a pipe created with os.popen(); why?: I can’t seem to use os read on a pipe created with os popen ; why?.
* How do I access the serial (RS232) port?: How do I access the serial RS232 port?.
* Why doesn’t closing sys.stdout (stdin, stderr) really close it?: Why doesn’t closing sys stdout stdin stderr really close it?.

Network/Internet Programming

* What WWW tools are there for Python?::
* What module should I use to help with generating HTML?::
* How do I send mail from a Python script?::
* How do I avoid blocking in the connect() method of a socket?: How do I avoid blocking in the connect method of a socket?.

Databases

* Are there any interfaces to database packages in Python?::
* How do you implement persistent objects in Python?::

Mathematics and Numerics

* How do I generate random numbers in Python?::

Extending/Embedding FAQ

* Can I create my own functions in C?::
* Can I create my own functions in C++?::
* Writing C is hard; are there any alternatives?::
* How can I execute arbitrary Python statements from C?::
* How can I evaluate an arbitrary Python expression from C?::
* How do I extract C values from a Python object?::
* How do I use Py_BuildValue() to create a tuple of arbitrary length?: How do I use Py_BuildValue to create a tuple of arbitrary length?.
* How do I call an object’s method from C?::
* How do I catch the output from PyErr_Print() (or anything that prints to stdout/stderr)?: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?.
* How do I access a module written in Python from C?::
* How do I interface to C++ objects from Python?::
* I added a module using the Setup file and the make fails; why?::
* How do I debug an extension?::
* I want to compile a Python module on my Linux system, but some files are missing. Why?: I want to compile a Python module on my Linux system but some files are missing Why?.
* How do I tell “incomplete input” from “invalid input”?::
* How do I find undefined g++ symbols __builtin_new or __pure_virtual?::
* Can I create an object class with some methods implemented in C and others in Python (e.g. through inheritance)?: Can I create an object class with some methods implemented in C and others in Python e g through inheritance ?.

Python on Windows FAQ

* How do I run a Python program under Windows?::
* How do I make Python scripts executable?::
* Why does Python sometimes take so long to start?::
* How do I make an executable from a Python script?::
* Is a *.pyd file the same as a DLL?: Is a * pyd file the same as a DLL?.
* How can I embed Python into a Windows application?::
* How do I keep editors from inserting tabs into my Python source?::
* How do I check for a keypress without blocking?::
* How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?.

Graphic User Interface FAQ

* General GUI Questions::
* What GUI toolkits exist for Python?::
* Tkinter questions::

Tkinter questions

* How do I freeze Tkinter applications?::
* Can I have Tk events handled while waiting for I/O?::
* I can’t get key bindings to work in Tkinter; why?: I can’t get key bindings to work in Tkinter why?.

“Why is Python Installed on my Computer?” FAQ

* What is Python?: What is Python?<2>.
* Why is Python installed on my machine?::
* Can I delete Python?::

Deprecations

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<5>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<5>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<5>.
* Pending removal in Python 3.17: Pending removal in Python 3 17<3>.
* Pending removal in Python 3.18: Pending removal in Python 3 18<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<5>.
* C API Deprecations::

C API Deprecations

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<6>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<6>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<6>.

About this documentation

* Contributors to the Python documentation::

Dealing with Bugs

* Documentation bugs::
* Using the Python issue tracker::
* Getting started contributing to Python yourself::

History and License

* History of the software::
* Terms and conditions for accessing or otherwise using Python::
* Licenses and Acknowledgements for Incorporated Software::

Terms and conditions for accessing or otherwise using Python

* PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2::
* BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 0.
* CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 1.
* CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 2.
* ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION::

Licenses and Acknowledgements for Incorporated Software

* Mersenne Twister::
* Sockets: Sockets<2>.
* Asynchronous socket services::
* Cookie management::
* Execution tracing::
* UUencode and UUdecode functions::
* XML Remote Procedure Calls::
* test_epoll::
* Select kqueue::
* SipHash24::
* strtod and dtoa::
* OpenSSL: OpenSSL<2>.
* expat::
* libffi::
* zlib: zlib<3>.
* cfuhash::
* libmpdec::
* W3C C14N test suite::
* mimalloc::
* asyncio: asyncio<12>.
* Global Unbounded Sequences (GUS): Global Unbounded Sequences GUS.



File: python.info,  Node: What’s New in Python,  Next: The Python Tutorial,  Prev: Top,  Up: Top

1 What’s New in Python
**********************

The “What’s New in Python” series of essays takes tours through the most
important changes between major Python versions.  They are a “must read”
for anyone wishing to stay up-to-date after a new release.

* Menu:

* What’s New In Python 3.13: What’s New In Python 3 13.
* What’s New In Python 3.12: What’s New In Python 3 12.
* What’s New In Python 3.11: What’s New In Python 3 11.
* What’s New In Python 3.10: What’s New In Python 3 10.
* What’s New In Python 3.9: What’s New In Python 3 9.
* What’s New In Python 3.8: What’s New In Python 3 8.
* What’s New In Python 3.7: What’s New In Python 3 7.
* What’s New In Python 3.6: What’s New In Python 3 6.
* What’s New In Python 3.5: What’s New In Python 3 5.
* What’s New In Python 3.4: What’s New In Python 3 4.
* What’s New In Python 3.3: What’s New In Python 3 3.
* What’s New In Python 3.2: What’s New In Python 3 2.
* What’s New In Python 3.1: What’s New In Python 3 1.
* What’s New In Python 3.0: What’s New In Python 3 0.
* What’s New in Python 2.7: What’s New in Python 2 7.
* What’s New in Python 2.6: What’s New in Python 2 6.
* What’s New in Python 2.5: What’s New in Python 2 5.
* What’s New in Python 2.4: What’s New in Python 2 4.
* What’s New in Python 2.3: What’s New in Python 2 3.
* What’s New in Python 2.2: What’s New in Python 2 2.
* What’s New in Python 2.1: What’s New in Python 2 1.
* What’s New in Python 2.0: What’s New in Python 2 0.
* Changelog::


File: python.info,  Node: What’s New In Python 3 13,  Next: What’s New In Python 3 12,  Up: What’s New in Python

1.1 What’s New In Python 3.13
=============================


Editors: Adam Turner and Thomas Wouters

This article explains the new features in Python 3.13, compared to 3.12.
Python 3.13 was released on October 7, 2024.  For full details, see the
*note changelog: 13c.

See also
........

PEP 719(1) – Python 3.13 Release Schedule

* Menu:

* Summary – Release Highlights::
* New Features::
* Other Language Changes::
* New Modules::
* Improved Modules::
* Optimizations::
* Removed Modules And APIs::
* New Deprecations::
* CPython Bytecode Changes::
* C API Changes::
* Build Changes::
* Porting to Python 3.13: Porting to Python 3 13.
* Regression Test Changes::
* Notable changes in 3.13.1: Notable changes in 3 13 1.
* Notable changes in 3.13.4: Notable changes in 3 13 4.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0719/


File: python.info,  Node: Summary – Release Highlights,  Next: New Features,  Up: What’s New In Python 3 13

1.1.1 Summary – Release Highlights
----------------------------------

Python 3.13 is the latest stable release of the Python programming
language, with a mix of changes to the language, the implementation and
the standard library.  The biggest changes include a new *note
interactive interpreter: 13e., experimental support for running in a
*note free-threaded mode: 13f.( PEP 703(1)), and a *note Just-In-Time
compiler: 140.( PEP 744(2)).

Error messages continue to improve, with tracebacks now highlighted in
color by default.  The *note locals(): 141. builtin now has *note
defined semantics: 142. for changing the returned mapping, and type
parameters now support default values.

The library changes contain removal of deprecated APIs and modules, as
well as the usual improvements in user-friendliness and correctness.
Several legacy standard library modules have now *note been removed:
143.following their deprecation in Python 3.11 ( PEP 594(3)).

This article doesn’t attempt to provide a complete specification of all
new features, but instead gives a convenient overview.  For full details
refer to the documentation, such as the *note Library Reference: 144.
and *note Language Reference: 145.  To understand the complete
implementation and design rationale for a change, refer to the PEP for a
particular new feature; but note that PEPs usually are not kept
up-to-date once a feature has been fully implemented.  See *note Porting
to Python 3.13: 146. for guidance on upgrading from earlier versions of
Python.

__________________________________________________________________

Interpreter improvements:

   * A greatly improved *note interactive interpreter: 13e. and *note
     improved error messages: 147.

   * PEP 667(4): The *note locals(): 141. builtin now has *note defined
     semantics: 142. when mutating the returned mapping.  Python
     debuggers and similar tools may now more reliably update local
     variables in optimized scopes even during concurrent code
     execution.

   * PEP 703(5): CPython 3.13 has experimental support for running with
     the *note global interpreter lock: 148. disabled.  See *note
     Free-threaded CPython: 13f. for more details.

   * PEP 744(6): A basic *note JIT compiler: 140. was added.  It is
     currently disabled by default (though we may turn it on later).
     Performance improvements are modest – we expect to improve this
     over the next few releases.

   * Color support in the new *note interactive interpreter: 13e, as
     well as in *note tracebacks: 147. and *note doctest: 149. output.
     This can be disabled through the *note PYTHON_COLORS: 14a. and
     NO_COLOR(7) environment variables.

Python data model improvements:

   * *note __static_attributes__: 14b. stores the names of attributes
     accessed through ‘self.X’ in any function in a class body.

   * *note __firstlineno__: 14c. records the first line number of a
     class definition.

Significant improvements in the standard library:

   * Add a new *note PythonFinalizationError: 14d. exception, raised
     when an operation is blocked during *note finalization: 14e.

   * The *note argparse: 6. module now supports deprecating command-line
     options, positional arguments, and subcommands.

   * The new functions *note base64.z85encode(): 14f. and *note
     base64.z85decode(): 150. support encoding and decoding Z85 data(8).

   * The *note copy: 25. module now has a *note copy.replace(): 151.
     function, with support for many builtin types and any class
     defining the *note __replace__(): 152. method.

   * The new *note dbm.sqlite3: 35. module is now the default *note dbm:
     31. backend.

   * The *note os: a1. module has a *note suite of new functions: 153.
     for working with Linux’s timer notification file descriptors.

   * The *note random: b8. module now has a *note command-line
     interface: 154.

Security improvements:

   * *note ssl.create_default_context(): 155. sets *note
     ssl.VERIFY_X509_PARTIAL_CHAIN: 156. and *note
     ssl.VERIFY_X509_STRICT: 157. as default flags.

C API improvements:

   * The *note Py_mod_gil: 158. slot is now used to indicate that an
     extension module supports running with the *note GIL: 159.
     disabled.

   * The *note PyTime C API: 15a. has been added, providing access to
     system clocks.

   * *note PyMutex: 15b. is a new lightweight mutex that occupies a
     single byte.

   * There is a new *note suite of functions: 15c. for generating PEP
     669(9) monitoring events in the C API.

New typing features:

   * PEP 696(10): Type parameters (*note typing.TypeVar: 15d, *note
     typing.ParamSpec: 15e, and *note typing.TypeVarTuple: 15f.) now
     support defaults.

   * PEP 702(11): The new *note warnings.deprecated(): 160. decorator
     adds support for marking deprecations in the type system and at
     runtime.

   * PEP 705(12): *note typing.ReadOnly: 161. can be used to mark an
     item of a *note typing.TypedDict: 162. as read-only for type
     checkers.

   * PEP 742(13): *note typing.TypeIs: 163. provides more intuitive type
     narrowing behavior, as an alternative to *note typing.TypeGuard:
     164.

Platform support:

   * PEP 730(14): Apple’s iOS is now an *note officially supported
     platform: 165, at tier 3(15).

   * PEP 738(16): Android is now an *note officially supported platform:
     165, at tier 3(17).

   * ‘wasm32-wasi’ is now supported as a tier 2(18) platform.

   * ‘wasm32-emscripten’ is no longer an officially supported platform.

Important removals:

   * *note PEP 594: 143.: The remaining 19 “dead batteries” (legacy
     stdlib modules) have been removed from the standard library:
     ‘aifc’, ‘audioop’, ‘cgi’, ‘cgitb’, ‘chunk’, ‘crypt’, ‘imghdr’,
     ‘mailcap’, ‘msilib’, ‘nis’, ‘nntplib’, ‘ossaudiodev’, ‘pipes’,
     ‘sndhdr’, ‘spwd’, ‘sunau’, ‘telnetlib’, ‘uu’ and ‘xdrlib’.

   * Remove the ‘2to3’ tool and ‘lib2to3’ module (deprecated in Python
     3.11).

   * Remove the ‘tkinter.tix’ module (deprecated in Python 3.6).

   * Remove the ‘locale.resetlocale()’ function.

   * Remove the ‘typing.io’ and ‘typing.re’ namespaces.

   * Remove chained *note classmethod: 166. descriptors.

Release schedule changes:

PEP 602(19) (“Annual Release Cycle for Python”) has been updated to
extend the full support (‘bugfix’) period for new releases to two years.
This updated policy means that:

   * Python 3.9–3.12 have one and a half years of full support, followed
     by three and a half years of security fixes.

   * Python 3.13 and later have two years of full support, followed by
     three years of security fixes.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/

   (2) https://peps.python.org/pep-0744/

   (3) https://peps.python.org/pep-0594/

   (4) https://peps.python.org/pep-0667/

   (5) https://peps.python.org/pep-0703/

   (6) https://peps.python.org/pep-0744/

   (7) https://no-color.org/

   (8) https://rfc.zeromq.org/spec/32/

   (9) https://peps.python.org/pep-0669/

   (10) https://peps.python.org/pep-0696/

   (11) https://peps.python.org/pep-0702/

   (12) https://peps.python.org/pep-0705/

   (13) https://peps.python.org/pep-0742/

   (14) https://peps.python.org/pep-0730/

   (15) https://peps.python.org/pep-0011/#tier-3

   (16) https://peps.python.org/pep-0738/

   (17) https://peps.python.org/pep-0011/#tier-3

   (18) https://peps.python.org/pep-0011/#tier-2

   (19) https://peps.python.org/pep-0602/


File: python.info,  Node: New Features,  Next: Other Language Changes,  Prev: Summary – Release Highlights,  Up: What’s New In Python 3 13

1.1.2 New Features
------------------

* Menu:

* A better interactive interpreter::
* Improved error messages::
* Free-threaded CPython::
* An experimental just-in-time (JIT) compiler: An experimental just-in-time JIT compiler.
* Defined mutation semantics for locals(): Defined mutation semantics for locals.
* Support for mobile platforms::


File: python.info,  Node: A better interactive interpreter,  Next: Improved error messages,  Up: New Features

1.1.2.1 A better interactive interpreter
........................................

Python now uses a new *note interactive: 169. shell by default, based on
code from the PyPy project(1).  When the user starts the *note REPL:
16a. from an interactive terminal, the following new features are now
supported:

   * Multiline editing with history preservation.

   * Direct support for REPL-specific commands like ‘help’, ‘exit’, and
     ‘quit’, without the need to call them as functions.

   * Prompts and tracebacks with *note color enabled by default: 16b.

   * Interactive help browsing using ‘F1’ with a separate command
     history.

   * History browsing using ‘F2’ that skips output as well as the *note
     >>>: 16c. and *note …: 16d. prompts.

   * “Paste mode” with ‘F3’ that makes pasting larger blocks of code
     easier (press ‘F3’ again to return to the regular prompt).

To disable the new interactive shell, set the *note PYTHON_BASIC_REPL:
16e. environment variable.  For more on interactive mode, see *note
Interactive Mode: 16f.

(Contributed by Pablo Galindo Salgado, Łukasz Langa, and Lysandros
Nikolaou in gh-111201(2) based on code from the PyPy project.  Windows
support contributed by Dino Viehland and Anthony Shaw.)

   ---------- Footnotes ----------

   (1) https://pypy.org/

   (2) https://github.com/python/cpython/issues/111201


File: python.info,  Node: Improved error messages,  Next: Free-threaded CPython,  Prev: A better interactive interpreter,  Up: New Features

1.1.2.2 Improved error messages
...............................

   * The interpreter now uses color by default when displaying
     tracebacks in the terminal.  This feature *note can be controlled:
     16b. via the new *note PYTHON_COLORS: 14a. environment variable as
     well as the canonical NO_COLOR(1) and FORCE_COLOR(2) environment
     variables.  (Contributed by Pablo Galindo Salgado in gh-112730(3).)

   * A common mistake is to write a script with the same name as a
     standard library module.  When this results in errors, we now
     display a more helpful error message:

          $ python random.py
          Traceback (most recent call last):
            File "/home/me/random.py", line 1, in <module>
              import random
            File "/home/me/random.py", line 3, in <module>
              print(random.randint(5))
                    ^^^^^^^^^^^^^^
          AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/me/random.py' since it has the same name as the standard library module named 'random' and prevents importing that standard library module)

     Similarly, if a script has the same name as a third-party module
     that it attempts to import and this results in errors, we also
     display a more helpful error message:

          $ python numpy.py
          Traceback (most recent call last):
            File "/home/me/numpy.py", line 1, in <module>
              import numpy as np
            File "/home/me/numpy.py", line 3, in <module>
              np.array([1, 2, 3])
              ^^^^^^^^
          AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/me/numpy.py' if it has the same name as a library you intended to import)

     (Contributed by Shantanu Jain in gh-95754(4).)

   * The error message now tries to suggest the correct keyword argument
     when an incorrect keyword argument is passed to a function.

          >>> "Better error messages!".split(max_split=1)
          Traceback (most recent call last):
            File "<python-input-0>", line 1, in <module>
              "Better error messages!".split(max_split=1)
              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^
          TypeError: split() got an unexpected keyword argument 'max_split'. Did you mean 'maxsplit'?

     (Contributed by Pablo Galindo Salgado and Shantanu Jain in
     gh-107944(5).)

   ---------- Footnotes ----------

   (1) https://no-color.org/

   (2) https://force-color.org/

   (3) https://github.com/python/cpython/issues/112730

   (4) https://github.com/python/cpython/issues/95754

   (5) https://github.com/python/cpython/issues/107944


File: python.info,  Node: Free-threaded CPython,  Next: An experimental just-in-time JIT compiler,  Prev: Improved error messages,  Up: New Features

1.1.2.3 Free-threaded CPython
.............................

CPython now has experimental support for running in a free-threaded
mode, with the *note global interpreter lock: 148. (GIL) disabled.  This
is an experimental feature and therefore is not enabled by default.  The
free-threaded mode requires a different executable, usually called
‘python3.13t’ or ‘python3.13t.exe’.  Pre-built binaries marked as
'free-threaded' can be installed as part of the official *note Windows:
172. and *note macOS: 173. installers, or CPython can be built from
source with the *note -disable-gil: 174. option.

Free-threaded execution allows for full utilization of the available
processing power by running threads in parallel on available CPU cores.
While not all software will benefit from this automatically, programs
designed with threading in mind will run faster on multi-core hardware.
'The free-threaded mode is experimental' and work is ongoing to improve
it: expect some bugs and a substantial single-threaded performance hit.
Free-threaded builds of CPython support optionally running with the GIL
enabled at runtime using the environment variable *note PYTHON_GIL: 175.
or the command-line option *note -X gil=1: 176.

To check if the current interpreter supports free-threading, *note
python -VV: 177. and *note sys.version: 178. contain “experimental
free-threading build”.  The new ‘sys._is_gil_enabled()’ function can be
used to check whether the GIL is actually disabled in the running
process.

C-API extension modules need to be built specifically for the
free-threaded build.  Extensions that support running with the *note
GIL: 159. disabled should use the *note Py_mod_gil: 158. slot.
Extensions using single-phase init should use *note
PyUnstable_Module_SetGIL(): 179. to indicate whether they support
running with the GIL disabled.  Importing C extensions that don’t use
these mechanisms will cause the GIL to be enabled, unless the GIL was
explicitly disabled with the *note PYTHON_GIL: 175. environment variable
or the *note -X gil=0: 176. option.  pip 24.1 or newer is required to
install packages with C extensions in the free-threaded build.

This work was made possible thanks to many individuals and
organizations, including the large community of contributors to Python
and third-party projects to test and enable free-threading support.
Notable contributors include: Sam Gross, Ken Jin, Donghee Na, Itamar
Oren, Matt Page, Brett Simmers, Dino Viehland, Carl Meyer, Nathan
Goldbaum, Ralf Gommers, Lysandros Nikolaou, and many others.  Many of
these contributors are employed by Meta, which has provided significant
engineering resources to support this project.

See also
........

PEP 703(1) “Making the Global Interpreter Lock Optional in CPython”
contains rationale and information surrounding this work.

Porting Extension Modules to Support Free-Threading(2): A
community-maintained porting guide for extension authors.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/

   (2) https://py-free-threading.github.io/porting/


File: python.info,  Node: An experimental just-in-time JIT compiler,  Next: Defined mutation semantics for locals,  Prev: Free-threaded CPython,  Up: New Features

1.1.2.4 An experimental just-in-time (JIT) compiler
...................................................

When CPython is configured and built using the
‘--enable-experimental-jit’ option, a just-in-time (JIT) compiler is
added which may speed up some Python programs.  On Windows, use
‘PCbuild/build.bat --experimental-jit’ to enable the JIT or
‘--experimental-jit-interpreter’ to enable the Tier 2 interpreter.
Build requirements and further supporting information are contained
at(1) ‘Tools/jit/README.md’.

The ‘--enable-experimental-jit’ option takes these (optional) values,
defaulting to ‘yes’ if ‘--enable-experimental-jit’ is present without
the optional value.

   * ‘no’: Disable the entire Tier 2 and JIT pipeline.

   * ‘yes’: Enable the JIT. To disable the JIT at runtime, pass the
     environment variable *note PYTHON_JIT=0: 17b.

   * ‘yes-off’: Build the JIT but disable it by default.  To enable the
     JIT at runtime, pass the environment variable *note PYTHON_JIT=1:
     17b.

   * ‘interpreter’: Enable the Tier 2 interpreter but disable the JIT.
     The interpreter can be disabled by running with *note PYTHON_JIT=0:
     17b.

The internal architecture is roughly as follows:

   * We start with specialized 'Tier 1 bytecode'.  See *note What’s new
     in 3.11: 17c. for details.

   * When the Tier 1 bytecode gets hot enough, it gets translated to a
     new purely internal intermediate representation (IR), called the
     'Tier 2 IR', and sometimes referred to as micro-ops (“uops”).

   * The Tier 2 IR uses the same stack-based virtual machine as Tier 1,
     but the instruction format is better suited to translation to
     machine code.

   * We have several optimization passes for Tier 2 IR, which are
     applied before it is interpreted or translated to machine code.

   * There is a Tier 2 interpreter, but it is mostly intended for
     debugging the earlier stages of the optimization pipeline.  The
     Tier 2 interpreter can be enabled by configuring Python with
     ‘--enable-experimental-jit=interpreter’.

   * When the JIT is enabled, the optimized Tier 2 IR is translated to
     machine code, which is then executed.

   * The machine code translation process uses a technique called
     'copy-and-patch'.  It has no runtime dependencies, but there is a
     new build-time dependency on LLVM.

See also
........

PEP 744(2)

(JIT by Brandt Bucher, inspired by a paper by Haoran Xu and Fredrik
Kjolstad.  Tier 2 IR by Mark Shannon and Guido van Rossum.  Tier 2
optimizer by Ken Jin.)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/blob/main/Tools/jit/README.md

   (2) https://peps.python.org/pep-0744/


File: python.info,  Node: Defined mutation semantics for locals,  Next: Support for mobile platforms,  Prev: An experimental just-in-time JIT compiler,  Up: New Features

1.1.2.5 Defined mutation semantics for ‘locals()’
.................................................

Historically, the expected result of mutating the return value of *note
locals(): 141. has been left to individual Python implementations to
define.  Starting from Python 3.13, PEP 667(1) standardises the
historical behavior of CPython for most code execution scopes, but
changes *note optimized scopes: 17e. (functions, generators, coroutines,
comprehensions, and generator expressions) to explicitly return
independent snapshots of the currently assigned local variables,
including locally referenced nonlocal variables captured in closures.

This change to the semantics of *note locals(): 141. in optimized scopes
also affects the default behavior of code execution functions that
implicitly target ‘locals()’ if no explicit namespace is provided (such
as *note exec(): 17f. and *note eval(): 180.).  In previous versions,
whether or not changes could be accessed by calling ‘locals()’ after
calling the code execution function was implementation-dependent.  In
CPython specifically, such code would typically appear to work as
desired, but could sometimes fail in optimized scopes based on other
code (including debuggers and code execution tracing tools) potentially
resetting the shared snapshot in that scope.  Now, the code will always
run against an independent snapshot of the local variables in optimized
scopes, and hence the changes will never be visible in subsequent calls
to ‘locals()’.  To access the changes made in these cases, an explicit
namespace reference must now be passed to the relevant function.
Alternatively, it may make sense to update affected code to use a higher
level code execution API that returns the resulting code execution
namespace (e.g.  *note runpy.run_path(): 181. when executing Python
files from disk).

To ensure debuggers and similar tools can reliably update local
variables in scopes affected by this change, *note FrameType.f_locals:
182. now returns a write-through proxy to the frame’s local and locally
referenced nonlocal variables in these scopes, rather than returning an
inconsistently updated shared ‘dict’ instance with undefined runtime
semantics.

See PEP 667(2) for more details, including related C API changes and
deprecations.  Porting notes are also provided below for the affected
*note Python APIs: 183. and *note C APIs: 184.

(PEP and implementation contributed by Mark Shannon and Tian Gao in
gh-74929(3).  Documentation updates provided by Guido van Rossum and
Alyssa Coghlan.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/

   (2) https://peps.python.org/pep-0667/

   (3) https://github.com/python/cpython/issues/74929


File: python.info,  Node: Support for mobile platforms,  Prev: Defined mutation semantics for locals,  Up: New Features

1.1.2.6 Support for mobile platforms
....................................

PEP 730(1): iOS is now a PEP 11(2) supported platform, with the
‘arm64-apple-ios’ and ‘arm64-apple-ios-simulator’ targets at tier 3
(iPhone and iPad devices released after 2013 and the Xcode iOS simulator
running on Apple silicon hardware, respectively).
‘x86_64-apple-ios-simulator’ (the Xcode iOS simulator running on older
‘x86_64’ hardware) is not a tier 3 supported platform, but will have
best-effort support.  (PEP written and implementation contributed by
Russell Keith-Magee in gh-114099(3).)

PEP 738(4): Android is now a PEP 11(5) supported platform, with the
‘aarch64-linux-android’ and ‘x86_64-linux-android’ targets at tier 3.
The 32-bit targets ‘arm-linux-androideabi’ and ‘i686-linux-android’ are
not tier 3 supported platforms, but will have best-effort support.  (PEP
written and implementation contributed by Malcolm Smith in
gh-116622(6).)

See also
........

PEP 730(7), PEP 738(8)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0730/

   (2) https://peps.python.org/pep-0011/

   (3) https://github.com/python/cpython/issues/114099

   (4) https://peps.python.org/pep-0738/

   (5) https://peps.python.org/pep-0011/

   (6) https://github.com/python/cpython/issues/116622

   (7) https://peps.python.org/pep-0730/

   (8) https://peps.python.org/pep-0738/


File: python.info,  Node: Other Language Changes,  Next: New Modules,  Prev: New Features,  Up: What’s New In Python 3 13

1.1.3 Other Language Changes
----------------------------

   * The compiler now strips common leading whitespace from every line
     in a docstring.  This reduces the size of the *note bytecode cache:
     187. (such as ‘.pyc’ files), with reductions in file size of around
     5%, for example in ‘sqlalchemy.orm.session’ from SQLAlchemy 2.0.
     This change affects tools that use docstrings, such as *note
     doctest: 3a.

          >>> def spam():
          ...     """
          ...         This is a docstring with
          ...           leading whitespace.
          ...
          ...         It even has multiple paragraphs!
          ...     """
          ...
          >>> spam.__doc__
          '\nThis is a docstring with\n  leading whitespace.\n\nIt even has multiple paragraphs!\n'

     (Contributed by Inada Naoki in gh-81283(1).)

   * *note Annotation scopes: 188. within class scopes can now contain
     lambdas and comprehensions.  Comprehensions that are located within
     class scopes are not inlined into their parent scope.

          class C[T]:
              type Alias = lambda: T

     (Contributed by Jelle Zijlstra in gh-109118(2) and gh-118160(3).)

   * *note Future statements: 189. are no longer triggered by relative
     imports of the *note __future__: 0. module, meaning that statements
     of the form ‘from .__future__ import ...’ are now simply standard
     relative imports, with no special features activated.  (Contributed
     by Jeremiah Gabriel Pascual in gh-118216(4).)

   * *note global: 18a. declarations are now permitted in *note except:
     18b. blocks when that global is used in the *note else: 18c. block.
     Previously this raised an erroneous *note SyntaxError: 18d.
     (Contributed by Irit Katriel in gh-111123(5).)

   * Add *note PYTHON_FROZEN_MODULES: 18e, a new environment variable
     that determines whether frozen modules are ignored by the import
     machinery, equivalent to the *note -X frozen_modules: 176.
     command-line option.  (Contributed by Yilei Yang in gh-111374(6).)

   * Add *note support for the perf profiler: 18f. working without frame
     pointers(7) through the new environment variable *note
     PYTHON_PERF_JIT_SUPPORT: 190. and command-line option *note -X
     perf_jit: 176.  (Contributed by Pablo Galindo in gh-118518(8).)

   * The location of a ‘.python_history’ file can be changed via the new
     *note PYTHON_HISTORY: 191. environment variable.  (Contributed by
     Levi Sabah, Zackery Spytz and Hugo van Kemenade in gh-73965(9).)

   * Classes have a new *note __static_attributes__: 14b. attribute.
     This is populated by the compiler with a tuple of the class’s
     attribute names which are assigned through ‘self.<name>’ from any
     function in its body.  (Contributed by Irit Katriel in
     gh-115775(10).)

   * The compiler now creates a ‘__firstlineno__’ attribute on classes
     with the line number of the first line of the class definition.
     (Contributed by Serhiy Storchaka in gh-118465(11).)

   * The *note exec(): 17f. and *note eval(): 180. builtins now accept
     the 'globals' and 'locals' arguments as keywords.  (Contributed by
     Raphael Gaschignard in gh-105879(12))

   * The *note compile(): 192. builtin now accepts a new flag,
     ‘ast.PyCF_OPTIMIZED_AST’, which is similar to ‘ast.PyCF_ONLY_AST’
     except that the returned AST is optimized according to the value of
     the 'optimize' argument.  (Contributed by Irit Katriel in
     gh-108113(13)).

   * Add a *note __name__: 193. attribute on *note property: 194.
     objects.  (Contributed by Eugene Toder in gh-101860(14).)

   * Add *note PythonFinalizationError: 14d, a new exception derived
     from *note RuntimeError: 195. and used to signal when operations
     are blocked during *note finalization: 14e.  The following
     callables now raise ‘PythonFinalizationError’, instead of
     ‘RuntimeError’:

        * *note _thread.start_new_thread(): 196.

        * *note os.fork(): 197.

        * *note os.forkpty(): 198.

        * *note subprocess.Popen: 199.

     (Contributed by Victor Stinner in gh-114570(15).)

   * Allow the 'count' argument of *note str.replace(): 19a. to be a
     keyword.  (Contributed by Hugo van Kemenade in gh-106487(16).)

   * Many functions now emit a warning if a boolean value is passed as a
     file descriptor argument.  This can help catch some errors earlier.
     (Contributed by Serhiy Storchaka in gh-82626(17).)

   * Added ‘name’ and ‘mode’ attributes for compressed and archived
     file-like objects in the *note bz2: 13, *note lzma: 8a, *note
     tarfile: de, and *note zipfile: 131. modules.  (Contributed by
     Serhiy Storchaka in gh-115961(18).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/81283

   (2) https://github.com/python/cpython/issues/109118

   (3) https://github.com/python/cpython/issues/118160

   (4) https://github.com/python/cpython/issues/118216

   (5) https://github.com/python/cpython/issues/111123

   (6) https://github.com/python/cpython/issues/111374

   (7) https://en.wikipedia.org/wiki/Call_stack

   (8) https://github.com/python/cpython/issues/118518

   (9) https://github.com/python/cpython/issues/73965

   (10) https://github.com/python/cpython/issues/115775

   (11) https://github.com/python/cpython/issues/118465

   (12) https://github.com/python/cpython/issues/105879

   (13) https://github.com/python/cpython/issues/108113

   (14) https://github.com/python/cpython/issues/101860

   (15) https://github.com/python/cpython/issues/114570

   (16) https://github.com/python/cpython/issues/106487

   (17) https://github.com/python/cpython/issues/82626

   (18) https://github.com/python/cpython/issues/115961


File: python.info,  Node: New Modules,  Next: Improved Modules,  Prev: Other Language Changes,  Up: What’s New In Python 3 13

1.1.4 New Modules
-----------------

   * *note dbm.sqlite3: 35.: An SQLite backend for *note dbm: 31.
     (Contributed by Raymond Hettinger and Erlend E. Aasland in
     gh-100414(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100414


File: python.info,  Node: Improved Modules,  Next: Optimizations,  Prev: New Modules,  Up: What’s New In Python 3 13

1.1.5 Improved Modules
----------------------

* Menu:

* argparse::
* array::
* ast::
* asyncio::
* base64::
* compileall::
* concurrent.futures: concurrent futures.
* configparser::
* copy::
* ctypes::
* dbm::
* dis::
* doctest::
* email::
* enum::
* fractions::
* glob::
* importlib::
* io::
* ipaddress::
* itertools::
* marshal::
* math::
* mimetypes::
* mmap::
* multiprocessing::
* os::
* os.path: os path.
* pathlib::
* pdb::
* queue::
* random::
* re::
* shutil::
* site::
* sqlite3::
* ssl::
* statistics::
* subprocess::
* sys::
* tempfile::
* time::
* tkinter::
* traceback::
* types::
* typing::
* unicodedata::
* venv::
* warnings::
* xml::
* zipimport::


File: python.info,  Node: argparse,  Next: array,  Up: Improved Modules

1.1.5.1 argparse
................

   * Add the 'deprecated' parameter to the *note add_argument(): 19e.
     and ‘add_parser()’ methods, to enable deprecating command-line
     options, positional arguments, and subcommands.  (Contributed by
     Serhiy Storchaka in gh-83648(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/83648


File: python.info,  Node: array,  Next: ast,  Prev: argparse,  Up: Improved Modules

1.1.5.2 array
.............

   * Add the ‘'w'’ type code (‘Py_UCS4’) for Unicode characters.  It
     should be used instead of the deprecated ‘'u'’ type code.
     (Contributed by Inada Naoki in gh-80480(1).)

   * Register *note array.array: 1a0. as a *note MutableSequence: 1a1.
     by implementing the *note clear(): 1a2. method.  (Contributed by
     Mike Zimin in gh-114894(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/80480

   (2) https://github.com/python/cpython/issues/114894


File: python.info,  Node: ast,  Next: asyncio,  Prev: array,  Up: Improved Modules

1.1.5.3 ast
...........

   * The constructors of node types in the *note ast: 8. module are now
     stricter in the arguments they accept, with more intuitive behavior
     when arguments are omitted.

     If an optional field on an AST node is not included as an argument
     when constructing an instance, the field will now be set to ‘None’.
     Similarly, if a list field is omitted, that field will now be set
     to an empty list, and if an ‘expr_context’ field is omitted, it
     defaults to *note Load(): 1a4.  (Previously, in all cases, the
     attribute would be missing on the newly constructed AST node
     instance.)

     In all other cases, where a required argument is omitted, the node
     constructor will emit a *note DeprecationWarning: 1a5.  This will
     raise an exception in Python 3.15.  Similarly, passing a keyword
     argument to the constructor that does not map to a field on the AST
     node is now deprecated, and will raise an exception in Python 3.15.

     These changes do not apply to user-defined subclasses of *note
     ast.AST: 1a6. unless the class opts in to the new behavior by
     defining the *note AST._field_types: 1a7. mapping.

     (Contributed by Jelle Zijlstra in gh-105858(1), gh-117486(2), and
     gh-118851(3).)

   * *note ast.parse(): 1a8. now accepts an optional argument 'optimize'
     which is passed on to *note compile(): 192.  This makes it possible
     to obtain an optimized AST. (Contributed by Irit Katriel in
     gh-108113(4).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105858

   (2) https://github.com/python/cpython/issues/117486

   (3) https://github.com/python/cpython/issues/118851

   (4) https://github.com/python/cpython/issues/108113


File: python.info,  Node: asyncio,  Next: base64,  Prev: ast,  Up: Improved Modules

1.1.5.4 asyncio
...............

   * *note asyncio.as_completed(): 1aa. now returns an object that is
     both an *note asynchronous iterator: 1ab. and a plain *note
     iterator: 1ac. of *note awaitables: 1ad.  The awaitables yielded by
     asynchronous iteration include original task or future objects that
     were passed in, making it easier to associate results with the
     tasks being completed.  (Contributed by Justin Arthur in
     gh-77714(1).)

   * *note asyncio.loop.create_unix_server(): 1ae. will now
     automatically remove the Unix socket when the server is closed.
     (Contributed by Pierre Ossman in gh-111246(2).)

   * *note DatagramTransport.sendto(): 1af. will now send zero-length
     datagrams if called with an empty bytes object.  The transport flow
     control also now accounts for the datagram header when calculating
     the buffer size.  (Contributed by Jamie Phan in gh-115199(3).)

   * Add *note Queue.shutdown: 1b0. and *note QueueShutDown: 1b1. to
     manage queue termination.  (Contributed by Laurie Opperman and Yves
     Duprat in gh-104228(4).)

   * Add the *note Server.close_clients(): 1b2. and *note
     Server.abort_clients(): 1b3. methods, which more forcefully close
     an asyncio server.  (Contributed by Pierre Ossman in gh-113538(5).)

   * Accept a tuple of separators in *note StreamReader.readuntil():
     1b4, stopping when any one of them is encountered.  (Contributed by
     Bruce Merry in gh-81322(6).)

   * Improve the behavior of *note TaskGroup: 1b5. when an external
     cancellation collides with an internal cancellation.  For example,
     when two task groups are nested and both experience an exception in
     a child task simultaneously, it was possible that the outer task
     group would hang, because its internal cancellation was swallowed
     by the inner task group.

     In the case where a task group is cancelled externally and also
     must raise an *note ExceptionGroup: 1b6, it will now call the
     parent task’s *note cancel(): 1b7. method.  This ensures that a
     *note CancelledError: 1b8. will be raised at the next *note await:
     1b9, so the cancellation is not lost.

     An added benefit of these changes is that task groups now preserve
     the cancellation count (*note cancelling(): 1ba.).

     In order to handle some corner cases, *note uncancel(): 1bb. may
     now reset the undocumented ‘_must_cancel’ flag when the
     cancellation count reaches zero.

     (Inspired by an issue reported by Arthur Tacca in gh-116720(7).)

   * When *note TaskGroup.create_task(): 1bc. is called on an inactive
     *note TaskGroup: 1b5, the given coroutine will be closed (which
     prevents a *note RuntimeWarning: 1bd. about the given coroutine
     being never awaited).  (Contributed by Arthur Tacca and Jason Zhang
     in gh-115957(8).)

   * The function and methods named ‘create_task’ have received a new
     ‘**kwargs’ argument that is passed through to the task constructor.
     This change was accidentally added in 3.13.3, and broke the API
     contract for custom task factories.  Several third-party task
     factories implemented workarounds for this.  In 3.13.4 and later
     releases the old factory contract is honored once again (until
     3.14).  To keep the workarounds working, the extra ‘**kwargs’
     argument still allows passing additional keyword arguments to *note
     Task: 1be. and to custom task factories.

     This affects the following function and methods: *note
     asyncio.create_task(): 1bf, *note asyncio.loop.create_task(): 1c0,
     *note asyncio.TaskGroup.create_task(): 1bc.  (Contributed by Thomas
     Grainger in gh-128307(9).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/77714

   (2) https://github.com/python/cpython/issues/111246

   (3) https://github.com/python/cpython/issues/115199

   (4) https://github.com/python/cpython/issues/104228

   (5) https://github.com/python/cpython/issues/113538

   (6) https://github.com/python/cpython/issues/81322

   (7) https://github.com/python/cpython/issues/116720

   (8) https://github.com/python/cpython/issues/115957

   (9) https://github.com/python/cpython/issues/128307


File: python.info,  Node: base64,  Next: compileall,  Prev: asyncio,  Up: Improved Modules

1.1.5.5 base64
..............

   * Add *note z85encode(): 14f. and *note z85decode(): 150. functions
     for encoding *note bytes: 1c2. as Z85 data(1) and decoding
     Z85-encoded data to ‘bytes’.  (Contributed by Matan Perelman in
     gh-75299(2).)

   ---------- Footnotes ----------

   (1) https://rfc.zeromq.org/spec/32/

   (2) https://github.com/python/cpython/issues/75299


File: python.info,  Node: compileall,  Next: concurrent futures,  Prev: base64,  Up: Improved Modules

1.1.5.6 compileall
..................

   * The default number of worker threads and processes is now selected
     using *note os.process_cpu_count(): 1c4. instead of *note
     os.cpu_count(): 1c5.  (Contributed by Victor Stinner in
     gh-109649(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109649


File: python.info,  Node: concurrent futures,  Next: configparser,  Prev: compileall,  Up: Improved Modules

1.1.5.7 concurrent.futures
..........................

   * The default number of worker threads and processes is now selected
     using *note os.process_cpu_count(): 1c4. instead of *note
     os.cpu_count(): 1c5.  (Contributed by Victor Stinner in
     gh-109649(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109649


File: python.info,  Node: configparser,  Next: copy,  Prev: concurrent futures,  Up: Improved Modules

1.1.5.8 configparser
....................

   * *note ConfigParser: 1c8. now has support for unnamed sections,
     which allows for top-level key-value pairs.  This can be enabled
     with the new 'allow_unnamed_section' parameter.  (Contributed by
     Pedro Sousa Lacerda in gh-66449(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/66449


File: python.info,  Node: copy,  Next: ctypes,  Prev: configparser,  Up: Improved Modules

1.1.5.9 copy
............

   * The new *note replace(): 151. function and the *note replace
     protocol: 152. make creating modified copies of objects much
     simpler.  This is especially useful when working with immutable
     objects.  The following types support the ‘replace()’ function and
     implement the replace protocol:

        * *note collections.namedtuple(): 1ca.

        * *note dataclasses.dataclass: 1cb.

        * *note datetime.datetime: 1cc, *note datetime.date: 1cd, *note
          datetime.time: 1ce.

        * *note inspect.Signature: 1cf, *note inspect.Parameter: 1d0.

        * *note types.SimpleNamespace: 1d1.

        * *note code objects: 1d2.

     Any user-defined class can also support *note copy.replace(): 151.
     by defining the *note __replace__(): 152. method.  (Contributed by
     Serhiy Storchaka in gh-108751(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/108751


File: python.info,  Node: ctypes,  Next: dbm,  Prev: copy,  Up: Improved Modules

1.1.5.10 ctypes
...............

   * As a consequence of necessary internal refactoring, initialization
     of internal metaclasses now happens in ‘__init__’ rather than in
     ‘__new__’.  This affects projects that subclass these internal
     metaclasses to provide custom initialization.  Generally:

        - Custom logic that was done in ‘__new__’ after calling
          ‘super().__new__’ should be moved to ‘__init__’.

        - To create a class, call the metaclass, not only the
          metaclass’s ‘__new__’ method.

     See gh-124520(1) for discussion and links to changes in some
     affected projects.

   * *note ctypes.Structure: 1d4. objects have a new *note _align_: 1d5.
     attribute which allows the alignment of the structure being packed
     to/from memory to be specified explicitly.  (Contributed by Matt
     Sanderson in gh-112433(2))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124520

   (2) https://github.com/python/cpython/issues/112433


File: python.info,  Node: dbm,  Next: dis,  Prev: ctypes,  Up: Improved Modules

1.1.5.11 dbm
............

   * Add *note dbm.sqlite3: 35, a new module which implements an SQLite
     backend, and make it the default ‘dbm’ backend.  (Contributed by
     Raymond Hettinger and Erlend E. Aasland in gh-100414(1).)

   * Allow removing all items from the database through the new
     ‘clear()’ methods of the GDBM and NDBM database objects.
     (Contributed by Donghee Na in gh-107122(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100414

   (2) https://github.com/python/cpython/issues/107122


File: python.info,  Node: dis,  Next: doctest,  Prev: dbm,  Up: Improved Modules

1.1.5.12 dis
............

   * Change the output of *note dis: 38. module functions to show
     logical labels for jump targets and exception handlers, rather than
     offsets.  The offsets can be added with the new *note -O: 1d8.
     command-line option or the 'show_offsets' argument.  (Contributed
     by Irit Katriel in gh-112137(1).)

   * *note get_instructions(): 1d9. no longer represents cache entries
     as separate instructions.  Instead, it returns them as part of the
     *note Instruction: 1da, in the new 'cache_info' field.  The
     'show_caches' argument to ‘get_instructions()’ is deprecated and no
     longer has any effect.  (Contributed by Irit Katriel in
     gh-112962(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112137

   (2) https://github.com/python/cpython/issues/112962


File: python.info,  Node: doctest,  Next: email,  Prev: dis,  Up: Improved Modules

1.1.5.13 doctest
................

   * *note doctest: 3a. output is now colored by default.  This can be
     controlled via the new *note PYTHON_COLORS: 14a. environment
     variable as well as the canonical NO_COLOR(1) and FORCE_COLOR(2)
     environment variables.  See also *note Controlling color: 16b.
     (Contributed by Hugo van Kemenade in gh-117225(3).)

   * The *note DocTestRunner.run(): 1dc. method now counts the number of
     skipped tests.  Add the *note DocTestRunner.skips: 1dd. and *note
     TestResults.skipped: 1de. attributes.  (Contributed by Victor
     Stinner in gh-108794(4).)

   ---------- Footnotes ----------

   (1) https://no-color.org/

   (2) https://force-color.org/

   (3) https://github.com/python/cpython/issues/117225

   (4) https://github.com/python/cpython/issues/108794


File: python.info,  Node: email,  Next: enum,  Prev: doctest,  Up: Improved Modules

1.1.5.14 email
..............

   * Headers with embedded newlines are now quoted on output.  The *note
     generator: 40. will now refuse to serialize (write) headers that
     are improperly folded or delimited, such that they would be parsed
     as multiple headers or joined with adjacent data.  If you need to
     turn this safety feature off, set *note verify_generated_headers:
     1e0.  (Contributed by Bas Bloemsaat and Petr Viktorin in
     gh-121650(1).)

   * *note getaddresses(): 1e1. and *note parseaddr(): 1e2. now return
     ‘('', '')’ pairs in more situations where invalid email addresses
     are encountered instead of potentially inaccurate values.  The two
     functions have a new optional 'strict' parameter (default ‘True’).
     To get the old behavior (accepting malformed input), use
     ‘strict=False’.  ‘getattr(email.utils, 'supports_strict_parsing',
     False)’ can be used to check if the 'strict' parameter is
     available.  (Contributed by Thomas Dwyer and Victor Stinner for
     gh-102988(2) to improve the CVE 2023-27043(3) fix.)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/121650

   (2) https://github.com/python/cpython/issues/102988

   (3) https://www.cve.org/CVERecord?id=CVE-2023-27043


File: python.info,  Node: enum,  Next: fractions,  Prev: email,  Up: Improved Modules

1.1.5.15 enum
.............

   * *note EnumDict: 1e4. has been made public to better support
     subclassing *note EnumType: 1e5.


File: python.info,  Node: fractions,  Next: glob,  Prev: enum,  Up: Improved Modules

1.1.5.16 fractions
..................

   * *note Fraction: 1e7. objects now support the standard *note format
     specification mini-language: 1e8. rules for fill, alignment, sign
     handling, minimum width, and grouping.  (Contributed by Mark
     Dickinson in gh-111320(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111320


File: python.info,  Node: glob,  Next: importlib,  Prev: fractions,  Up: Improved Modules

1.1.5.17 glob
.............

   * Add *note translate(): 1ea, a function to convert a path
     specification with shell-style wildcards to a regular expression.
     (Contributed by Barney Gale in gh-72904(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/72904


File: python.info,  Node: importlib,  Next: io,  Prev: glob,  Up: Improved Modules

1.1.5.18 importlib
..................

   * The following functions in *note importlib.resources: 7b. now allow
     accessing a directory (or tree) of resources, using multiple
     positional arguments (the 'encoding' and 'errors' arguments in the
     text-reading functions are now keyword-only):

        * *note is_resource(): 1ec.

        * *note open_binary(): 1ed.

        * *note open_text(): 1ee.

        * *note path(): 1ef.

        * *note read_binary(): 1f0.

        * *note read_text(): 1f1.

     These functions are no longer deprecated and are not scheduled for
     removal.  (Contributed by Petr Viktorin in gh-116608(1).)

   * *note contents(): 1f2. remains deprecated in favor of the
     fully-featured *note Traversable: 1f3. API. However, there is now
     no plan to remove it.  (Contributed by Petr Viktorin in
     gh-116608(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116608

   (2) https://github.com/python/cpython/issues/116608


File: python.info,  Node: io,  Next: ipaddress,  Prev: importlib,  Up: Improved Modules

1.1.5.19 io
...........

   * The *note IOBase: 1f5. finalizer now logs any errors raised by the
     *note close(): 1f6. method with *note sys.unraisablehook: 1f7.
     Previously, errors were ignored silently by default, and only
     logged in *note Python Development Mode: 1f8. or when using a *note
     Python debug build: 1f9.  (Contributed by Victor Stinner in
     gh-62948(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/62948


File: python.info,  Node: ipaddress,  Next: itertools,  Prev: io,  Up: Improved Modules

1.1.5.20 ipaddress
..................

   * Add the *note IPv4Address.ipv6_mapped: 1fb. property, which returns
     the IPv4-mapped IPv6 address.  (Contributed by Charles Machalow in
     gh-109466(1).)

   * Fix ‘is_global’ and ‘is_private’ behavior in *note IPv4Address:
     1fc, *note IPv6Address: 1fd, *note IPv4Network: 1fe, and *note
     IPv6Network: 1ff.  (Contributed by Jakub Stasiak in gh-113171(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109466

   (2) https://github.com/python/cpython/issues/113171


File: python.info,  Node: itertools,  Next: marshal,  Prev: ipaddress,  Up: Improved Modules

1.1.5.21 itertools
..................

   * *note batched(): 201. has a new 'strict' parameter, which raises a
     *note ValueError: 202. if the final batch is shorter than the
     specified batch size.  (Contributed by Raymond Hettinger in
     gh-113202(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113202


File: python.info,  Node: marshal,  Next: math,  Prev: itertools,  Up: Improved Modules

1.1.5.22 marshal
................

   * Add the 'allow_code' parameter in module functions.  Passing
     ‘allow_code=False’ prevents serialization and de-serialization of
     code objects which are incompatible between Python versions.
     (Contributed by Serhiy Storchaka in gh-113626(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113626


File: python.info,  Node: math,  Next: mimetypes,  Prev: marshal,  Up: Improved Modules

1.1.5.23 math
.............

   * The new function *note fma(): 205. performs fused multiply-add
     operations.  This computes ‘x * y + z’ with only a single round,
     and so avoids any intermediate loss of precision.  It wraps the
     ‘fma()’ function provided by C99, and follows the specification of
     the IEEE 754 “fusedMultiplyAdd” operation for special cases.
     (Contributed by Mark Dickinson and Victor Stinner in gh-73468(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/73468


File: python.info,  Node: mimetypes,  Next: mmap,  Prev: math,  Up: Improved Modules

1.1.5.24 mimetypes
..................

   * Add the *note guess_file_type(): 207. function to guess a MIME type
     from a filesystem path.  Using paths with *note guess_type(): 208.
     is now *note soft deprecated: 209.  (Contributed by Serhiy
     Storchaka in gh-66543(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/66543


File: python.info,  Node: mmap,  Next: multiprocessing,  Prev: mimetypes,  Up: Improved Modules

1.1.5.25 mmap
.............

   * *note mmap: 20b. is now protected from crashing on Windows when the
     mapped memory is inaccessible due to file system errors or access
     violations.  (Contributed by Jannis Weigend in gh-118209(1).)

   * *note mmap: 20b. has a new *note seekable(): 20c. method that can
     be used when a seekable file-like object is required.  The *note
     seek(): 20d. method now returns the new absolute position.
     (Contributed by Donghee Na and Sylvie Liberman in gh-111835(2).)

   * The new UNIX-only 'trackfd' parameter for *note mmap: 20b. controls
     file descriptor duplication; if false, the file descriptor
     specified by 'fileno' will not be duplicated.  (Contributed by
     Zackery Spytz and Petr Viktorin in gh-78502(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118209

   (2) https://github.com/python/cpython/issues/111835

   (3) https://github.com/python/cpython/issues/78502


File: python.info,  Node: multiprocessing,  Next: os,  Prev: mmap,  Up: Improved Modules

1.1.5.26 multiprocessing
........................

   * The default number of worker threads and processes is now selected
     using *note os.process_cpu_count(): 1c4. instead of *note
     os.cpu_count(): 1c5.  (Contributed by Victor Stinner in
     gh-109649(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109649


File: python.info,  Node: os,  Next: os path,  Prev: multiprocessing,  Up: Improved Modules

1.1.5.27 os
...........

   * Add *note process_cpu_count(): 1c4. function to get the number of
     logical CPU cores usable by the calling thread of the current
     process.  (Contributed by Victor Stinner in gh-109649(1).)

   * *note cpu_count(): 1c5. and *note process_cpu_count(): 1c4. can be
     overridden through the new environment variable *note
     PYTHON_CPU_COUNT: 210. or the new command-line option *note -X
     cpu_count: 176.  This option is useful for users who need to limit
     CPU resources of a container system without having to modify
     application code or the container itself.  (Contributed by Donghee
     Na in gh-109595(2).)

   * Add a *note low level interface: 153. to Linux’s ‘timer file
     descriptors(3)’ via *note timerfd_create(): 211, *note
     timerfd_settime(): 212, *note timerfd_settime_ns(): 213, *note
     timerfd_gettime(): 214, *note timerfd_gettime_ns(): 215, *note
     TFD_NONBLOCK: 216, *note TFD_CLOEXEC: 217, *note TFD_TIMER_ABSTIME:
     218, and *note TFD_TIMER_CANCEL_ON_SET: 219. (Contributed by Masaru
     Tsuchiyama in gh-108277(4).)

   * *note lchmod(): 21a. and the 'follow_symlinks' argument of *note
     chmod(): 21b. are both now available on Windows.  Note that the
     default value of 'follow_symlinks' in ‘lchmod()’ is ‘False’ on
     Windows.  (Contributed by Serhiy Storchaka in gh-59616(5).)

   * *note fchmod(): 21c. and support for file descriptors in *note
     chmod(): 21b. are both now available on Windows.  (Contributed by
     Serhiy Storchaka in gh-113191(6).)

   * On Windows, *note mkdir(): 21d. and *note makedirs(): 21e. now
     support passing a 'mode' value of ‘0o700’ to apply access control
     to the new directory.  This implicitly affects *note
     tempfile.mkdtemp(): 21f. and is a mitigation for CVE 2024-4030(7).
     Other values for 'mode' continue to be ignored.  (Contributed by
     Steve Dower in gh-118486(8).)

   * *note posix_spawn(): 220. now accepts ‘None’ for the 'env'
     argument, which makes the newly spawned process use the current
     process environment.  (Contributed by Jakub Kulik in gh-113119(9).)

   * *note posix_spawn(): 220. can now use the *note
     POSIX_SPAWN_CLOSEFROM: 221. attribute in the 'file_actions'
     parameter on platforms that support
     ‘posix_spawn_file_actions_addclosefrom_np()’.  (Contributed by
     Jakub Kulik in gh-113117(10).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109649

   (2) https://github.com/python/cpython/issues/109595

   (3) https://manpages.debian.org/timerfd_create(2)

   (4) https://github.com/python/cpython/issues/108277

   (5) https://github.com/python/cpython/issues/59616

   (6) https://github.com/python/cpython/issues/113191

   (7) https://www.cve.org/CVERecord?id=CVE-2024-4030

   (8) https://github.com/python/cpython/issues/118486

   (9) https://github.com/python/cpython/issues/113119

   (10) https://github.com/python/cpython/issues/113117


File: python.info,  Node: os path,  Next: pathlib,  Prev: os,  Up: Improved Modules

1.1.5.28 os.path
................

   * Add *note isreserved(): 223. to check if a path is reserved on the
     current system.  This function is only available on Windows.
     (Contributed by Barney Gale in gh-88569(1).)

   * On Windows, *note isabs(): 224. no longer considers paths starting
     with exactly one slash (‘\’ or ‘/’) to be absolute.  (Contributed
     by Barney Gale and Jon Foster in gh-44626(2).)

   * *note realpath(): 225. now resolves MS-DOS style file names even if
     the file is not accessible.  (Contributed by Moonsik Park in
     gh-82367(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88569

   (2) https://github.com/python/cpython/issues/44626

   (3) https://github.com/python/cpython/issues/82367


File: python.info,  Node: pathlib,  Next: pdb,  Prev: os path,  Up: Improved Modules

1.1.5.29 pathlib
................

   * Add *note UnsupportedOperation: 227, which is raised instead of
     *note NotImplementedError: 228. when a path operation isn’t
     supported.  (Contributed by Barney Gale in gh-89812(1).)

   * Add a new constructor for creating *note Path: 229. objects from
     ‘file’ URIs (‘file:///’), *note Path.from_uri(): 22a.  (Contributed
     by Barney Gale in gh-107465(2).)

   * Add *note PurePath.full_match(): 22b. for matching paths with
     shell-style wildcards, including the recursive wildcard “‘**’”.
     (Contributed by Barney Gale in gh-73435(3).)

   * Add the *note PurePath.parser: 22c. class attribute to store the
     implementation of *note os.path: a2. used for low-level path
     parsing and joining.  This will be either ‘posixpath’ or ‘ntpath’.

   * Add 'recurse_symlinks' keyword-only argument to *note Path.glob():
     22d. and *note rglob(): 22e.  (Contributed by Barney Gale in
     gh-77609(4).)

   * *note Path.glob(): 22d. and *note rglob(): 22e. now return files
     and directories when given a pattern that ends with “‘**’”.
     Previously, only directories were returned.  (Contributed by Barney
     Gale in gh-70303(5).)

   * Add the 'follow_symlinks' keyword-only argument to *note
     Path.is_file: 22f, *note Path.is_dir: 230, *note Path.owner(): 231,
     and *note Path.group(): 232.  (Contributed by Barney Gale in
     gh-105793(6) and Kamil Turek in gh-107962(7).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89812

   (2) https://github.com/python/cpython/issues/107465

   (3) https://github.com/python/cpython/issues/73435

   (4) https://github.com/python/cpython/issues/77609

   (5) https://github.com/python/cpython/issues/70303

   (6) https://github.com/python/cpython/issues/105793

   (7) https://github.com/python/cpython/issues/107962


File: python.info,  Node: pdb,  Next: queue,  Prev: pathlib,  Up: Improved Modules

1.1.5.30 pdb
............

   * *note breakpoint(): 234. and *note set_trace(): 235. now enter the
     debugger immediately rather than on the next line of code to be
     executed.  This change prevents the debugger from breaking outside
     of the context when ‘breakpoint()’ is positioned at the end of the
     context.  (Contributed by Tian Gao in gh-118579(1).)

   * ‘sys.path[0]’ is no longer replaced by the directory of the script
     being debugged when *note sys.flags.safe_path: 236. is set.
     (Contributed by Tian Gao and Christian Walther in gh-111762(2).)

   * *note zipapp: 130. is now supported as a debugging target.
     (Contributed by Tian Gao in gh-118501(3).)

   * Add ability to move between chained exceptions during post-mortem
     debugging in *note pm(): 237. using the new *note exceptions
     [exc_number]: 238. command for Pdb.  (Contributed by Matthias
     Bussonnier in gh-106676(4).)

   * Expressions and statements whose prefix is a pdb command are now
     correctly identified and executed.  (Contributed by Tian Gao in
     gh-108464(5).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118579

   (2) https://github.com/python/cpython/issues/111762

   (3) https://github.com/python/cpython/issues/118501

   (4) https://github.com/python/cpython/issues/106676

   (5) https://github.com/python/cpython/issues/108464


File: python.info,  Node: queue,  Next: random,  Prev: pdb,  Up: Improved Modules

1.1.5.31 queue
..............

   * Add *note Queue.shutdown: 23a. and *note ShutDown: 23b. to manage
     queue termination.  (Contributed by Laurie Opperman and Yves Duprat
     in gh-104750(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104750


File: python.info,  Node: random,  Next: re,  Prev: queue,  Up: Improved Modules

1.1.5.32 random
...............

   * Add a *note command-line interface: 154.  (Contributed by Hugo van
     Kemenade in gh-118131(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118131


File: python.info,  Node: re,  Next: shutil,  Prev: random,  Up: Improved Modules

1.1.5.33 re
...........

   * Rename ‘re.error’ to *note PatternError: 23e. for improved clarity.
     ‘re.error’ is kept for backward compatibility.


File: python.info,  Node: shutil,  Next: site,  Prev: re,  Up: Improved Modules

1.1.5.34 shutil
...............

   * Support the 'dir_fd' and 'follow_symlinks' keyword arguments in
     *note chown(): 240.  (Contributed by Berker Peksag and Tahia K in
     gh-62308(1))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/62308


File: python.info,  Node: site,  Next: sqlite3,  Prev: shutil,  Up: Improved Modules

1.1.5.35 site
.............

   * ‘.pth’ files are now decoded using UTF-8 first, and then with the
     *note locale encoding: 242. if UTF-8 decoding fails.  (Contributed
     by Inada Naoki in gh-117802(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117802


File: python.info,  Node: sqlite3,  Next: ssl,  Prev: site,  Up: Improved Modules

1.1.5.36 sqlite3
................

   * A *note ResourceWarning: 244. is now emitted if a *note Connection:
     245. object is not *note closed: 246. explicitly.  (Contributed by
     Erlend E. Aasland in gh-105539(1).)

   * Add the 'filter' keyword-only parameter to *note
     Connection.iterdump(): 247. for filtering database objects to dump.
     (Contributed by Mariusz Felisiak in gh-91602(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105539

   (2) https://github.com/python/cpython/issues/91602


File: python.info,  Node: ssl,  Next: statistics,  Prev: sqlite3,  Up: Improved Modules

1.1.5.37 ssl
............

   * The *note create_default_context(): 155. API now includes *note
     VERIFY_X509_PARTIAL_CHAIN: 156. and *note VERIFY_X509_STRICT: 157.
     in its default flags.

          Note: *note VERIFY_X509_STRICT: 157. may reject pre- RFC
          5280(1) or malformed certificates that the underlying OpenSSL
          implementation might otherwise accept.  Whilst disabling this
          is not recommended, you can do so using:

               import ssl

               ctx = ssl.create_default_context()
               ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT

     (Contributed by William Woodruff in gh-112389(2).)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5280.html

   (2) https://github.com/python/cpython/issues/112389


File: python.info,  Node: statistics,  Next: subprocess,  Prev: ssl,  Up: Improved Modules

1.1.5.38 statistics
...................

   * Add *note kde(): 24a. for kernel density estimation.  This makes it
     possible to estimate a continuous probability density function from
     a fixed number of discrete samples.  (Contributed by Raymond
     Hettinger in gh-115863(1).)

   * Add *note kde_random(): 24b. for sampling from an estimated
     probability density function created by *note kde(): 24a.
     (Contributed by Raymond Hettinger in gh-115863(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115863

   (2) https://github.com/python/cpython/issues/115863


File: python.info,  Node: subprocess,  Next: sys,  Prev: statistics,  Up: Improved Modules

1.1.5.39 subprocess
...................

   * The *note subprocess: d6. module now uses the *note posix_spawn():
     220. function in more situations.

     Notably, when 'close_fds' is ‘True’ (the default), *note
     posix_spawn(): 220. will be used when the C library provides
     ‘posix_spawn_file_actions_addclosefrom_np()’, which includes recent
     versions of Linux, FreeBSD, and Solaris.  On Linux, this should
     perform similarly to the existing Linux ‘vfork()’ based code.

     A private control knob ‘subprocess._USE_POSIX_SPAWN’ can be set to
     ‘False’ if you need to force *note subprocess: d6. to never use
     *note posix_spawn(): 220.  Please report your reason and platform
     details in the *note issue tracker: 24e. if you set this so that we
     can improve our API selection logic for everyone.  (Contributed by
     Jakub Kulik in gh-113117(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113117


File: python.info,  Node: sys,  Next: tempfile,  Prev: subprocess,  Up: Improved Modules

1.1.5.40 sys
............

   * Add the *note _is_interned(): 250. function to test if a string was
     interned.  This function is not guaranteed to exist in all
     implementations of Python.  (Contributed by Serhiy Storchaka in
     gh-78573(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/78573


File: python.info,  Node: tempfile,  Next: time,  Prev: sys,  Up: Improved Modules

1.1.5.41 tempfile
.................

   * On Windows, the default mode ‘0o700’ used by *note
     tempfile.mkdtemp(): 21f. now limits access to the new directory due
     to changes to *note os.mkdir(): 21d.  This is a mitigation for CVE
     2024-4030(1).  (Contributed by Steve Dower in gh-118486(2).)

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2024-4030

   (2) https://github.com/python/cpython/issues/118486


File: python.info,  Node: time,  Next: tkinter,  Prev: tempfile,  Up: Improved Modules

1.1.5.42 time
.............

   * On Windows, *note monotonic(): 253. now uses the
     ‘QueryPerformanceCounter()’ clock for a resolution of 1
     microsecond, instead of the ‘GetTickCount64()’ clock which has a
     resolution of 15.6 milliseconds.  (Contributed by Victor Stinner in
     gh-88494(1).)

   * On Windows, *note time(): 254. now uses the
     ‘GetSystemTimePreciseAsFileTime()’ clock for a resolution of 1
     microsecond, instead of the ‘GetSystemTimeAsFileTime()’ clock which
     has a resolution of 15.6 milliseconds.  (Contributed by Victor
     Stinner in gh-63207(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88494

   (2) https://github.com/python/cpython/issues/63207


File: python.info,  Node: tkinter,  Next: traceback,  Prev: time,  Up: Improved Modules

1.1.5.43 tkinter
................

   * Add *note tkinter: f0. widget methods: ‘tk_busy_hold()’,
     ‘tk_busy_configure()’, ‘tk_busy_cget()’, ‘tk_busy_forget()’,
     ‘tk_busy_current()’, and ‘tk_busy_status()’.  (Contributed by
     Miguel, klappnase and Serhiy Storchaka in gh-72684(1).)

   * The *note tkinter: f0. widget method ‘wm_attributes()’ now accepts
     the attribute name without the minus prefix to get window
     attributes, for example ‘w.wm_attributes('alpha')’ and allows
     specifying attributes and values to set as keyword arguments, for
     example ‘w.wm_attributes(alpha=0.5)’.  (Contributed by Serhiy
     Storchaka in gh-43457(2).)

   * ‘wm_attributes()’ can now return attributes as a *note dict: 256,
     by using the new optional keyword-only parameter
     'return_python_dict'.  (Contributed by Serhiy Storchaka in
     gh-43457(3).)

   * ‘Text.count()’ can now return a simple *note int: 257. when the new
     optional keyword-only parameter 'return_ints' is used.  Otherwise,
     the single count is returned as a 1-tuple or ‘None’.  (Contributed
     by Serhiy Storchaka in gh-97928(4).)

   * Support the “vsapi” element type in the *note element_create():
     258. method of *note tkinter.ttk.Style: 259.  (Contributed by
     Serhiy Storchaka in gh-68166(5).)

   * Add the ‘after_info()’ method for Tkinter widgets.  (Contributed by
     Cheryl Sabella in gh-77020(6).)

   * Add a new ‘copy_replace()’ method to ‘PhotoImage’ to copy a region
     from one image to another, possibly with pixel zooming,
     subsampling, or both.  (Contributed by Serhiy Storchaka in
     gh-118225(7).)

   * Add 'from_coords' parameter to the ‘PhotoImage’ methods ‘copy()’,
     ‘zoom()’ and ‘subsample()’.  Add 'zoom' and 'subsample' parameters
     to the ‘PhotoImage’ method ‘copy()’.  (Contributed by Serhiy
     Storchaka in gh-118225(8).)

   * Add the ‘PhotoImage’ methods ‘read()’ to read an image from a file
     and ‘data()’ to get the image data.  Add 'background' and
     'grayscale' parameters to the ‘write()’ method.  (Contributed by
     Serhiy Storchaka in gh-118271(9).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/72684

   (2) https://github.com/python/cpython/issues/43457

   (3) https://github.com/python/cpython/issues/43457

   (4) https://github.com/python/cpython/issues/97928

   (5) https://github.com/python/cpython/issues/68166

   (6) https://github.com/python/cpython/issues/77020

   (7) https://github.com/python/cpython/issues/118225

   (8) https://github.com/python/cpython/issues/118225

   (9) https://github.com/python/cpython/issues/118271


File: python.info,  Node: traceback,  Next: types,  Prev: tkinter,  Up: Improved Modules

1.1.5.44 traceback
..................

   * Add the *note exc_type_str: 25b. attribute to *note
     TracebackException: 25c, which holds a string display of the
     'exc_type'.  Deprecate the *note exc_type: 25d. attribute, which
     holds the type object itself.  Add parameter 'save_exc_type'
     (default ‘True’) to indicate whether ‘exc_type’ should be saved.
     (Contributed by Irit Katriel in gh-112332(1).)

   * Add a new 'show_group' keyword-only parameter to *note
     TracebackException.format_exception_only(): 25e. to (recursively)
     format the nested exceptions of a *note BaseExceptionGroup: 25f.
     instance.  (Contributed by Irit Katriel in gh-105292(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112332

   (2) https://github.com/python/cpython/issues/105292


File: python.info,  Node: types,  Next: typing,  Prev: traceback,  Up: Improved Modules

1.1.5.45 types
..............

   * *note SimpleNamespace: 1d1. can now take a single positional
     argument to initialise the namespace’s arguments.  This argument
     must either be a mapping or an iterable of key-value pairs.
     (Contributed by Serhiy Storchaka in gh-108191(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/108191


File: python.info,  Node: typing,  Next: unicodedata,  Prev: types,  Up: Improved Modules

1.1.5.46 typing
...............

   * PEP 705(1): Add *note ReadOnly: 161, a special typing construct to
     mark a *note TypedDict: 162. item as read-only for type checkers.

   * PEP 742(2): Add *note TypeIs: 163, a typing construct that can be
     used to instruct a type checker how to narrow a type.

   * Add *note NoDefault: 262, a sentinel object used to represent the
     defaults of some parameters in the *note typing: 104. module.
     (Contributed by Jelle Zijlstra in gh-116126(3).)

   * Add *note get_protocol_members(): 263. to return the set of members
     defining a *note typing.Protocol: 264.  (Contributed by Jelle
     Zijlstra in gh-104873(4).)

   * Add *note is_protocol(): 265. to check whether a class is a *note
     Protocol: 264.  (Contributed by Jelle Zijlstra in gh-104873(5).)

   * *note ClassVar: 266. can now be nested in *note Final: 267, and
     vice versa.  (Contributed by Mehdi Drissi in gh-89547(6).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0705/

   (2) https://peps.python.org/pep-0742/

   (3) https://github.com/python/cpython/issues/116126

   (4) https://github.com/python/cpython/issues/104873

   (5) https://github.com/python/cpython/issues/104873

   (6) https://github.com/python/cpython/issues/89547


File: python.info,  Node: unicodedata,  Next: venv,  Prev: typing,  Up: Improved Modules

1.1.5.47 unicodedata
....................

   * Update the Unicode database to version 15.1.0(1).  (Contributed by
     James Gerity in gh-109559(2).)

   ---------- Footnotes ----------

   (1) https://www.unicode.org/versions/Unicode15.1.0/

   (2) https://github.com/python/cpython/issues/109559


File: python.info,  Node: venv,  Next: warnings,  Prev: unicodedata,  Up: Improved Modules

1.1.5.48 venv
.............

   * Add support for creating source control management (SCM) ignore
     files in a virtual environment’s directory.  By default, Git is
     supported.  This is implemented as opt-in via the API, which can be
     extended to support other SCMs (*note EnvBuilder: 26a. and *note
     create(): 26b.), and opt-out via the CLI, using
     ‘--without-scm-ignore-files’.  (Contributed by Brett Cannon in
     gh-108125(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/108125


File: python.info,  Node: warnings,  Next: xml,  Prev: venv,  Up: Improved Modules

1.1.5.49 warnings
.................

   * PEP 702(1): The new *note warnings.deprecated(): 160. decorator
     provides a way to communicate deprecations to a *note static type
     checker: 26d. and to warn on usage of deprecated classes and
     functions.  A *note DeprecationWarning: 1a5. may also be emitted
     when a decorated function or class is used at runtime.
     (Contributed by Jelle Zijlstra in gh-104003(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0702/

   (2) https://github.com/python/cpython/issues/104003


File: python.info,  Node: xml,  Next: zipimport,  Prev: warnings,  Up: Improved Modules

1.1.5.50 xml
............

   * Allow controlling Expat >=2.6.0 reparse deferral ( CVE
     2023-52425(1)) by adding five new methods:

        * *note xml.etree.ElementTree.XMLParser.flush(): 26f.

        * *note xml.etree.ElementTree.XMLPullParser.flush(): 270.

        * *note xml.parsers.expat.xmlparser.GetReparseDeferralEnabled():
          271.

        * *note xml.parsers.expat.xmlparser.SetReparseDeferralEnabled():
          272.

        * ‘xml.sax.expatreader.ExpatParser.flush()’

     (Contributed by Sebastian Pipping in gh-115623(2).)

   * Add the ‘close()’ method for the iterator returned by *note
     iterparse(): 273. for explicit cleanup.  (Contributed by Serhiy
     Storchaka in gh-69893(3).)

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2023-52425

   (2) https://github.com/python/cpython/issues/115623

   (3) https://github.com/python/cpython/issues/69893


File: python.info,  Node: zipimport,  Prev: xml,  Up: Improved Modules

1.1.5.51 zipimport
..................

   * Add support for ZIP64(1) format files.  Everybody loves huge data,
     right?  (Contributed by Tim Hatch in gh-94146(2).)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Zip_(file_format)#ZIP64

   (2) https://github.com/python/cpython/issues/94146


File: python.info,  Node: Optimizations,  Next: Removed Modules And APIs,  Prev: Improved Modules,  Up: What’s New In Python 3 13

1.1.6 Optimizations
-------------------

   * Several standard library modules have had their import times
     significantly improved.  For example, the import time of the *note
     typing: 104. module has been reduced by around a third by removing
     dependencies on *note re: b9. and *note contextlib: 23.  Other
     modules to enjoy import-time speedups include *note email.utils:
     50, *note enum: 56, *note functools: 5f, *note importlib.metadata:
     7a, and *note threading: ed.  (Contributed by Alex Waygood,
     Shantanu Jain, Adam Turner, Daniel Hollas, and others in
     gh-109653(1).)

   * *note textwrap.indent(): 276. is now around 30% faster than before
     for large input.  (Contributed by Inada Naoki in gh-107369(2).)

   * The *note subprocess: d6. module now uses the *note posix_spawn():
     220. function in more situations, including when 'close_fds' is
     ‘True’ (the default) on many modern platforms.  This should provide
     a notable performance increase when launching processes on FreeBSD
     and Solaris.  See the *note subprocess: 24d. section above for
     details.  (Contributed by Jakub Kulik in gh-113117(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109653

   (2) https://github.com/python/cpython/issues/107369

   (3) https://github.com/python/cpython/issues/113117


File: python.info,  Node: Removed Modules And APIs,  Next: New Deprecations,  Prev: Optimizations,  Up: What’s New In Python 3 13

1.1.7 Removed Modules And APIs
------------------------------

* Menu:

* PEP 594; Remove “dead batteries” from the standard library: PEP 594 Remove “dead batteries” from the standard library.
* 2to3::
* builtins::
* configparser: configparser<2>.
* importlib.metadata: importlib metadata.
* locale::
* opcode::
* optparse::
* pathlib: pathlib<2>.
* re: re<2>.
* tkinter.tix: tkinter tix.
* turtle::
* typing: typing<2>.
* unittest::
* urllib::
* webbrowser::


File: python.info,  Node: PEP 594 Remove “dead batteries” from the standard library,  Next: 2to3,  Up: Removed Modules And APIs

1.1.7.1 PEP 594: Remove “dead batteries” from the standard library
..................................................................

PEP 594(1) proposed removing 19 modules from the standard library,
colloquially referred to as ‘dead batteries’ due to their historic,
obsolete, or insecure status.  All of the following modules were
deprecated in Python 3.11, and are now removed:

   * ‘aifc’

        * standard-aifc(2): Use the redistribution of ‘aifc’ library
          from PyPI.

   * ‘audioop’

        * audioop-lts(3): Use ‘audioop-lts’ library from PyPI.

   * ‘chunk’

        * standard-chunk(4): Use the redistribution of ‘chunk’ library
          from PyPI.

   * ‘cgi’ and ‘cgitb’

        * ‘cgi.FieldStorage’ can typically be replaced with *note
          urllib.parse.parse_qsl(): 279. for ‘GET’ and ‘HEAD’ requests,
          and the *note email.message: 44. module or the multipart(5)
          library for ‘POST’ and ‘PUT’ requests.

        * ‘cgi.parse()’ can be replaced by calling *note
          urllib.parse.parse_qs(): 27a. directly on the desired query
          string, unless the input is ‘multipart/form-data’, which
          should be replaced as described below for
          ‘cgi.parse_multipart()’.

        * ‘cgi.parse_header()’ can be replaced with the functionality in
          the *note email: 3b. package, which implements the same MIME
          RFCs.  For example, with *note email.message.EmailMessage:
          27b.:

               from email.message import EmailMessage

               msg = EmailMessage()
               msg['content-type'] = 'application/json; charset="utf8"'
               main, params = msg.get_content_type(), msg['content-type'].params

        * ‘cgi.parse_multipart()’ can be replaced with the functionality
          in the *note email: 3b. package, which implements the same
          MIME RFCs, or with the multipart(6) library.  For example, the
          *note email.message.EmailMessage: 27b. and *note
          email.message.Message: 27c. classes.

        * standard-cgi(7): and standard-cgitb(8): Use the redistribution
          of ‘cgi’ and ‘cgitb’ library from PyPI.

   * ‘crypt’ and the private ‘_crypt’ extension.  The *note hashlib: 68.
     module may be an appropriate replacement when simply hashing a
     value is required.  Otherwise, various third-party libraries on
     PyPI are available:

        * bcrypt(9): Modern password hashing for your software and your
          servers.

        * argon2-cffi(10): The secure Argon2 password hashing algorithm.

        * legacycrypt(11): *note ctypes: 2a. wrapper to the POSIX crypt
          library call and associated functionality.

        * crypt_r(12): Fork of the ‘crypt’ module, wrapper to the
          ‘crypt_r(3)(13)’ library call and associated functionality.

        * standard-crypt(14) and deprecated-crypt-alternative(15): Use
          the redistribution of ‘crypt’ and reimplementation of ‘_crypt’
          libraries from PyPI.

   * ‘imghdr’: The filetype(16), puremagic(17), or python-magic(18)
     libraries should be used as replacements.  For example, the
     ‘puremagic.what()’ function can be used to replace the
     ‘imghdr.what()’ function for all file formats that were supported
     by ‘imghdr’.

        * standard-imghdr(19): Use the redistribution of ‘imghdr’
          library from PyPI.

   * ‘mailcap’: Use the *note mimetypes: 8f. module instead.

        * standard-mailcap(20): Use the redistribution of ‘mailcap’
          library from PyPI.

   * ‘msilib’

   * ‘nis’

   * ‘nntplib’: Use the pynntp(21) library from PyPI instead.

        * standard-nntplib(22): Use the redistribution of ‘nntplib’
          library from PyPI.

   * ‘ossaudiodev’: For audio playback, use the pygame(23) library from
     PyPI instead.

   * ‘pipes’: Use the *note subprocess: d6. module instead.  Use *note
     shlex.quote(): 27d. to replace the undocumented ‘pipes.quote’
     function.

        * standard-pipes(24): Use the redistribution of ‘pipes’ library
          from PyPI.

   * ‘sndhdr’: The filetype(25), puremagic(26), or python-magic(27)
     libraries should be used as replacements.

        * standard-sndhdr(28): Use the redistribution of ‘sndhdr’
          library from PyPI.

   * ‘spwd’: Use the python-pam(29) library from PyPI instead.

   * ‘sunau’

        * standard-sunau(30): Use the redistribution of ‘sunau’ library
          from PyPI.

   * ‘telnetlib’, Use the telnetlib3(31) or Exscript(32) libraries from
     PyPI instead.

        * standard-telnetlib(33): Use the redistribution of ‘telnetlib’
          library from PyPI.

   * ‘uu’: Use the *note base64: e. module instead, as a modern
     alternative.

        * standard-uu(34): Use the redistribution of ‘uu’ library from
          PyPI.

   * ‘xdrlib’

        * standard-xdrlib(35): Use the redistribution of ‘xdrlib’
          library from PyPI.

(Contributed by Victor Stinner and Zachary Ware in gh-104773(36) and
gh-104780(37).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/standard-aifc/

   (3) https://pypi.org/project/audioop-lts/

   (4) https://pypi.org/project/standard-chunk/

   (5) https://pypi.org/project/multipart/

   (6) https://pypi.org/project/multipart/

   (7) https://pypi.org/project/standard-cgi/

   (8) https://pypi.org/project/standard-cgitb/

   (9) https://pypi.org/project/bcrypt/

   (10) https://pypi.org/project/argon2-cffi/

   (11) https://pypi.org/project/legacycrypt/

   (12) https://pypi.org/project/crypt_r/

   (13) https://manpages.debian.org/crypt_r(3)

   (14) https://pypi.org/project/standard-crypt/

   (15) https://pypi.org/project/deprecated-crypt-alternative/

   (16) https://pypi.org/project/filetype/

   (17) https://pypi.org/project/puremagic/

   (18) https://pypi.org/project/python-magic/

   (19) https://pypi.org/project/standard-imghdr/

   (20) https://pypi.org/project/standard-mailcap/

   (21) https://pypi.org/project/pynntp/

   (22) https://pypi.org/project/standard-nntplib/

   (23) https://pypi.org/project/pygame/

   (24) https://pypi.org/project/standard-pipes/

   (25) https://pypi.org/project/filetype/

   (26) https://pypi.org/project/puremagic/

   (27) https://pypi.org/project/python-magic/

   (28) https://pypi.org/project/standard-sndhdr/

   (29) https://pypi.org/project/python-pam/

   (30) https://pypi.org/project/standard-sunau/

   (31) https://pypi.org/project/telnetlib3/

   (32) https://pypi.org/project/Exscript/

   (33) https://pypi.org/project/standard-telnetlib/

   (34) https://pypi.org/project/standard-uu/

   (35) https://pypi.org/project/standard-xdrlib/

   (36) https://github.com/python/cpython/issues/104773

   (37) https://github.com/python/cpython/issues/104780


File: python.info,  Node: 2to3,  Next: builtins,  Prev: PEP 594 Remove “dead batteries” from the standard library,  Up: Removed Modules And APIs

1.1.7.2 2to3
............

   * Remove the ‘2to3’ program and the ‘lib2to3’ module, previously
     deprecated in Python 3.11.  (Contributed by Victor Stinner in
     gh-104780(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104780


File: python.info,  Node: builtins,  Next: configparser<2>,  Prev: 2to3,  Up: Removed Modules And APIs

1.1.7.3 builtins
................

   * Remove support for chained *note classmethod: 166. descriptors
     (introduced in gh-63272(1)).  These can no longer be used to wrap
     other descriptors, such as *note property: 194.  The core design of
     this feature was flawed and led to several problems.  To
     “pass-through” a ‘classmethod’, consider using the ‘__wrapped__’
     attribute that was added in Python 3.10.  (Contributed by Raymond
     Hettinger in gh-89519(2).)

   * Raise a *note RuntimeError: 195. when calling *note frame.clear():
     280. on a suspended frame (as has always been the case for an
     executing frame).  (Contributed by Irit Katriel in gh-79932(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/63272

   (2) https://github.com/python/cpython/issues/89519

   (3) https://github.com/python/cpython/issues/79932


File: python.info,  Node: configparser<2>,  Next: importlib metadata,  Prev: builtins,  Up: Removed Modules And APIs

1.1.7.4 configparser
....................

   * Remove the undocumented ‘LegacyInterpolation’ class, deprecated in
     the docstring since Python 3.2, and at runtime since Python 3.11.
     (Contributed by Hugo van Kemenade in gh-104886(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104886


File: python.info,  Node: importlib metadata,  Next: locale,  Prev: configparser<2>,  Up: Removed Modules And APIs

1.1.7.5 importlib.metadata
..........................

   * Remove deprecated subscript (*note __getitem__(): 283.) access for
     *note EntryPoint: 284. objects.  (Contributed by Jason R. Coombs in
     gh-113175(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113175


File: python.info,  Node: locale,  Next: opcode,  Prev: importlib metadata,  Up: Removed Modules And APIs

1.1.7.6 locale
..............

   * Remove the ‘locale.resetlocale()’ function, deprecated in Python
     3.11.  Use ‘locale.setlocale(locale.LC_ALL, "")’ instead.
     (Contributed by Victor Stinner in gh-104783(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104783


File: python.info,  Node: opcode,  Next: optparse,  Prev: locale,  Up: Removed Modules And APIs

1.1.7.7 opcode
..............

   * Move ‘opcode.ENABLE_SPECIALIZATION’ to
     ‘_opcode.ENABLE_SPECIALIZATION’.  This field was added in 3.12, it
     was never documented, and is not intended for external use.
     (Contributed by Irit Katriel in gh-105481(1).)

   * Remove ‘opcode.is_pseudo()’, ‘opcode.MIN_PSEUDO_OPCODE’, and
     ‘opcode.MAX_PSEUDO_OPCODE’, which were added in Python 3.12, but
     were neither documented nor exposed through *note dis: 38, and were
     not intended to be used externally.  (Contributed by Irit Katriel
     in gh-105481(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105481

   (2) https://github.com/python/cpython/issues/105481


File: python.info,  Node: optparse,  Next: pathlib<2>,  Prev: opcode,  Up: Removed Modules And APIs

1.1.7.8 optparse
................

   * This module is no longer considered *note soft deprecated: 209.
     While *note argparse: 6. remains preferred for new projects that
     aren’t using a third party command line argument processing
     library, there are aspects of the way ‘argparse’ works that mean
     the lower level ‘optparse’ module may provide a better foundation
     for 'writing' argument processing libraries, and for implementing
     command line applications which adhere more strictly than
     ‘argparse’ does to various Unix command line processing conventions
     that originate in the behaviour of the C ‘getopt()’ function .
     (Contributed by Alyssa Coghlan and Serhiy Storchaka in
     gh-126180(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126180


File: python.info,  Node: pathlib<2>,  Next: re<2>,  Prev: optparse,  Up: Removed Modules And APIs

1.1.7.9 pathlib
...............

   * Remove the ability to use *note Path: 229. objects as context
     managers.  This functionality was deprecated and has had no effect
     since Python 3.9.  (Contributed by Barney Gale in gh-83863(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/83863


File: python.info,  Node: re<2>,  Next: tkinter tix,  Prev: pathlib<2>,  Up: Removed Modules And APIs

1.1.7.10 re
...........

   * Remove the undocumented, deprecated, and broken ‘re.template()’
     function and ‘re.TEMPLATE’ / ‘re.T’ flag.  (Contributed by Serhiy
     Storchaka and Nikita Sobolev in gh-105687(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105687


File: python.info,  Node: tkinter tix,  Next: turtle,  Prev: re<2>,  Up: Removed Modules And APIs

1.1.7.11 tkinter.tix
....................

   * Remove the ‘tkinter.tix’ module, deprecated in Python 3.6.  The
     third-party Tix library which the module wrapped is unmaintained.
     (Contributed by Zachary Ware in gh-75552(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/75552


File: python.info,  Node: turtle,  Next: typing<2>,  Prev: tkinter tix,  Up: Removed Modules And APIs

1.1.7.12 turtle
...............

   * Remove the ‘RawTurtle.settiltangle()’ method, deprecated in the
     documentation since Python 3.1 and at runtime since Python 3.11.
     (Contributed by Hugo van Kemenade in gh-104876(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104876


File: python.info,  Node: typing<2>,  Next: unittest,  Prev: turtle,  Up: Removed Modules And APIs

1.1.7.13 typing
...............

   * Remove the ‘typing.io’ and ‘typing.re’ namespaces, deprecated since
     Python 3.8.  The items in those namespaces can be imported directly
     from the *note typing: 104. module.  (Contributed by Sebastian
     Rittau in gh-92871(1).)

   * Remove the keyword-argument method of creating *note TypedDict:
     162. types, deprecated in Python 3.11.  (Contributed by Tomas Roun
     in gh-104786(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92871

   (2) https://github.com/python/cpython/issues/104786


File: python.info,  Node: unittest,  Next: urllib,  Prev: typing<2>,  Up: Removed Modules And APIs

1.1.7.14 unittest
.................

   * Remove the following *note unittest: 106. functions, deprecated in
     Python 3.11:

        * ‘unittest.findTestCases()’

        * ‘unittest.makeSuite()’

        * ‘unittest.getTestCaseNames()’

     Use *note TestLoader: 28e. methods instead:

        * *note loadTestsFromModule(): 28f.

        * *note loadTestsFromTestCase(): 290.

        * *note getTestCaseNames(): 291.

     (Contributed by Hugo van Kemenade in gh-104835(1).)

   * Remove the untested and undocumented ‘TestProgram.usageExit()’
     method, deprecated in Python 3.11.  (Contributed by Hugo van
     Kemenade in gh-104992(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104835

   (2) https://github.com/python/cpython/issues/104992


File: python.info,  Node: urllib,  Next: webbrowser,  Prev: unittest,  Up: Removed Modules And APIs

1.1.7.15 urllib
...............

   * Remove the 'cafile', 'capath', and 'cadefault' parameters of the
     *note urllib.request.urlopen(): 293. function, deprecated in Python
     3.6.  Use the 'context' parameter instead with an *note SSLContext:
     294. instance.  The *note ssl.SSLContext.load_cert_chain(): 295.
     function can be used to load specific certificates, or let *note
     ssl.create_default_context(): 155. select the operating system’s
     trusted certificate authority (CA) certificates.  (Contributed by
     Victor Stinner in gh-105382(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105382


File: python.info,  Node: webbrowser,  Prev: urllib,  Up: Removed Modules And APIs

1.1.7.16 webbrowser
...................

   * Remove the untested and undocumented ‘MacOSX’ class, deprecated in
     Python 3.11.  Use the ‘MacOSXOSAScript’ class (introduced in Python
     3.2) instead.  (Contributed by Hugo van Kemenade in gh-104804(1).)

   * Remove the deprecated ‘MacOSXOSAScript._name’ attribute.  Use the
     *note MacOSXOSAScript.name: 297. attribute instead.  (Contributed
     by Nikita Sobolev in gh-105546(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104804

   (2) https://github.com/python/cpython/issues/105546


File: python.info,  Node: New Deprecations,  Next: CPython Bytecode Changes,  Prev: Removed Modules And APIs,  Up: What’s New In Python 3 13

1.1.8 New Deprecations
----------------------

   * *note User-defined functions: 299.:

        * Deprecate assignment to a function’s *note __code__: 29a.
          attribute, where the new code object’s type does not match the
          function’s type.  The different types are: plain function,
          generator, async generator, and coroutine.  (Contributed by
          Irit Katriel in gh-81137(1).)

   * *note array: 7.:

        * Deprecate the ‘'u'’ format code (‘wchar_t’) at runtime.  This
          format code has been deprecated in documentation since Python
          3.3, and will be removed in Python 3.16.  Use the ‘'w'’ format
          code (*note Py_UCS4: 29b.) for Unicode characters instead.
          (Contributed by Hugo van Kemenade in gh-80480(2).)

   * *note ctypes: 2a.:

        * Deprecate the undocumented ‘SetPointerType()’ function, to be
          removed in Python 3.15.  (Contributed by Victor Stinner in
          gh-105733(3).)

        * *note Soft-deprecate: 209. the *note ARRAY(): 29c. function in
          favour of ‘type * length’ multiplication.  (Contributed by
          Victor Stinner in gh-105733(4).)

   * *note decimal: 36.:

        * Deprecate the non-standard and undocumented *note Decimal:
          29d. format specifier ‘'N'’, which is only supported in the
          ‘decimal’ module’s C implementation.  Scheduled to be removed
          in Python 3.18.  (Contributed by Serhiy Storchaka in
          gh-89902(5).)

   * *note dis: 38.:

        * Deprecate the ‘HAVE_ARGUMENT’ separator.  Check membership in
          *note hasarg: 29e. instead.  (Contributed by Irit Katriel in
          gh-109319(6).)

   * *note gettext: 63.:

        * Deprecate non-integer numbers as arguments to functions and
          methods that consider plural forms in the ‘gettext’ module,
          even if no translation was found.  (Contributed by Serhiy
          Storchaka in gh-88434(7).)

   * *note glob: 64.:

        * Deprecate the undocumented ‘glob0()’ and ‘glob1()’ functions.
          Use *note glob(): 29f. and pass a *note path-like object: 2a0.
          specifying the root directory to the 'root_dir' parameter
          instead.  (Contributed by Barney Gale in gh-117337(8).)

   * *note http.server: 72.:

        * Deprecate *note CGIHTTPRequestHandler: 2a1, to be removed in
          Python 3.15.  Process-based CGI HTTP servers have been out of
          favor for a very long time.  This code was outdated,
          unmaintained, and rarely used.  It has a high potential for
          both security and functionality bugs.  (Contributed by Gregory
          P. Smith in gh-109096(9).)

        * Deprecate the ‘--cgi’ flag to the ‘python -m http.server’
          command-line interface, to be removed in Python 3.15.
          (Contributed by Gregory P. Smith in gh-109096(10).)

   * *note mimetypes: 8f.:

        * *note Soft-deprecate: 209. file path arguments to *note
          guess_type(): 208, use *note guess_file_type(): 207. instead.
          (Contributed by Serhiy Storchaka in gh-66543(11).)

   * *note re: b9.:

        * Deprecate passing the optional 'maxsplit', 'count', or 'flags'
          arguments as positional arguments to the module-level *note
          split(): 2a2, *note sub(): 2a3, and *note subn(): 2a4.
          functions.  These parameters will become *note keyword-only:
          2a5. in a future version of Python.  (Contributed by Serhiy
          Storchaka in gh-56166(12).)

   * *note pathlib: a4.:

        * Deprecate *note PurePath.is_reserved(): 2a6, to be removed in
          Python 3.15.  Use *note os.path.isreserved(): 223. to detect
          reserved paths on Windows.  (Contributed by Barney Gale in
          gh-88569(13).)

   * *note platform: aa.:

        * Deprecate *note java_ver(): 2a7, to be removed in Python 3.15.
          This function is only useful for Jython support, has a
          confusing API, and is largely untested.  (Contributed by
          Nikita Sobolev in gh-116349(14).)

   * *note pydoc: b5.:

        * Deprecate the undocumented ‘ispackage()’ function.
          (Contributed by Zackery Spytz in gh-64020(15).)

   * *note sqlite3: cf.:

        * Deprecate passing more than one positional argument to the
          *note connect(): 2a8. function and the *note Connection: 245.
          constructor.  The remaining parameters will become
          keyword-only in Python 3.15.  (Contributed by Erlend E.
          Aasland in gh-107948(16).)

        * Deprecate passing name, number of arguments, and the callable
          as keyword arguments for *note Connection.create_function():
          2a9. and *note Connection.create_aggregate(): 2aa. These
          parameters will become positional-only in Python 3.15.
          (Contributed by Erlend E. Aasland in gh-108278(17).)

        * Deprecate passing the callback callable by keyword for the
          *note set_authorizer(): 2ab, *note set_progress_handler():
          2ac, and *note set_trace_callback(): 2ad. *note Connection:
          245. methods.  The callback callables will become
          positional-only in Python 3.15.  (Contributed by Erlend E.
          Aasland in gh-108278(18).)

   * *note sys: d9.:

        * Deprecate the *note _enablelegacywindowsfsencoding(): 2ae.
          function, to be removed in Python 3.16.  Use the *note
          PYTHONLEGACYWINDOWSFSENCODING: 2af. environment variable
          instead.  (Contributed by Inada Naoki in gh-73427(19).)

   * *note tarfile: de.:

        * Deprecate the undocumented and unused ‘TarFile.tarfile’
          attribute, to be removed in Python 3.16.  (Contributed in
          gh-115256(20).)

   * *note traceback: fe.:

        * Deprecate the *note TracebackException.exc_type: 25d.
          attribute.  Use *note TracebackException.exc_type_str: 25b.
          instead.  (Contributed by Irit Katriel in gh-112332(21).)

   * *note typing: 104.:

        * Deprecate the undocumented keyword argument syntax for
          creating *note NamedTuple: 2b0. classes (e.g.  ‘Point =
          NamedTuple("Point", x=int, y=int)’), to be removed in Python
          3.15.  Use the class-based syntax or the functional syntax
          instead.  (Contributed by Alex Waygood in gh-105566(22).)

        * Deprecate omitting the 'fields' parameter when creating a
          *note NamedTuple: 2b0. or *note typing.TypedDict: 162. class,
          and deprecate passing ‘None’ to the 'fields' parameter of both
          types.  Python 3.15 will require a valid sequence for the
          'fields' parameter.  To create a NamedTuple class with zero
          fields, use ‘class NT(NamedTuple): pass’ or ‘NT =
          NamedTuple("NT", ())’.  To create a TypedDict class with zero
          fields, use ‘class TD(TypedDict): pass’ or ‘TD =
          TypedDict("TD", {})’.  (Contributed by Alex Waygood in
          gh-105566(23) and gh-105570(24).)

        * Deprecate the *note typing.no_type_check_decorator(): 2b1.
          decorator function, to be removed in Python 3.15.  After eight
          years in the *note typing: 104. module, it has yet to be
          supported by any major type checker.  (Contributed by Alex
          Waygood in gh-106309(25).)

        * Deprecate *note typing.AnyStr: 2b2.  In Python 3.16, it will
          be removed from ‘typing.__all__’, and a *note
          DeprecationWarning: 1a5. will be emitted at runtime when it is
          imported or accessed.  It will be removed entirely in Python
          3.18.  Use the new *note type parameter syntax: 2b3. instead.
          (Contributed by Michael The in gh-107116(26).)

   * *note wave: 113.:

        * Deprecate the *note getmark(): 2b4, ‘setmark()’, and *note
          getmarkers(): 2b5. methods of the *note Wave_read: 2b6. and
          *note Wave_write: 2b7. classes, to be removed in Python 3.15.
          (Contributed by Victor Stinner in gh-105096(27).)

* Menu:

* Pending Removal in Python 3.14: Pending Removal in Python 3 14.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15.
* Pending removal in Python 3.16: Pending removal in Python 3 16.
* Pending removal in Python 3.17: Pending removal in Python 3 17.
* Pending removal in Python 3.18: Pending removal in Python 3 18.
* Pending Removal in Future Versions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/81137

   (2) https://github.com/python/cpython/issues/80480

   (3) https://github.com/python/cpython/issues/105733

   (4) https://github.com/python/cpython/issues/105733

   (5) https://github.com/python/cpython/issues/89902

   (6) https://github.com/python/cpython/issues/109319

   (7) https://github.com/python/cpython/issues/88434

   (8) https://github.com/python/cpython/issues/117337

   (9) https://github.com/python/cpython/issues/109096

   (10) https://github.com/python/cpython/issues/109096

   (11) https://github.com/python/cpython/issues/66543

   (12) https://github.com/python/cpython/issues/56166

   (13) https://github.com/python/cpython/issues/88569

   (14) https://github.com/python/cpython/issues/116349

   (15) https://github.com/python/cpython/issues/64020

   (16) https://github.com/python/cpython/issues/107948

   (17) https://github.com/python/cpython/issues/108278

   (18) https://github.com/python/cpython/issues/108278

   (19) https://github.com/python/cpython/issues/73427

   (20) https://github.com/python/cpython/issues/115256

   (21) https://github.com/python/cpython/issues/112332

   (22) https://github.com/python/cpython/issues/105566

   (23) https://github.com/python/cpython/issues/105566

   (24) https://github.com/python/cpython/issues/105570

   (25) https://github.com/python/cpython/issues/106309

   (26) https://github.com/python/cpython/issues/107116

   (27) https://github.com/python/cpython/issues/105096


File: python.info,  Node: Pending Removal in Python 3 14,  Next: Pending Removal in Python 3 15,  Up: New Deprecations

1.1.8.1 Pending Removal in Python 3.14
......................................

   * *note argparse: 6.: The 'type', 'choices', and 'metavar' parameters
     of ‘argparse.BooleanOptionalAction’ are deprecated and will be
     removed in 3.14.  (Contributed by Nikita Sobolev in gh-92248(1).)

   * *note ast: 8.: The following features have been deprecated in
     documentation since Python 3.8, now cause a *note
     DeprecationWarning: 1a5. to be emitted at runtime when they are
     accessed or used, and will be removed in Python 3.14:

        * ‘ast.Num’

        * ‘ast.Str’

        * ‘ast.Bytes’

        * ‘ast.NameConstant’

        * ‘ast.Ellipsis’

     Use *note ast.Constant: 2b9. instead.  (Contributed by Serhiy
     Storchaka in gh-90953(2).)

   * *note asyncio: a.:

        * The child watcher classes *note MultiLoopChildWatcher: 2ba,
          *note FastChildWatcher: 2bb, *note AbstractChildWatcher: 2bc.
          and *note SafeChildWatcher: 2bd. are deprecated and will be
          removed in Python 3.14.  (Contributed by Kumar Aditya in
          gh-94597(3).)

        * *note asyncio.set_child_watcher(): 2be, *note
          asyncio.get_child_watcher(): 2bf, *note
          asyncio.AbstractEventLoopPolicy.set_child_watcher(): 2c0. and
          *note asyncio.AbstractEventLoopPolicy.get_child_watcher():
          2c1. are deprecated and will be removed in Python 3.14.
          (Contributed by Kumar Aditya in gh-94597(4).)

        * The *note get_event_loop(): 2c2. method of the default event
          loop policy now emits a *note DeprecationWarning: 1a5. if
          there is no current event loop set and it decides to create
          one.  (Contributed by Serhiy Storchaka and Guido van Rossum in
          gh-100160(5).)

   * *note builtins: 12.: ‘bool(NotImplemented)’ now emits a *note
     DeprecationWarning: 1a5. and will raise a *note TypeError: 2c3. in
     Python 3.14.  (Contributed by Jelle Zijlstra in gh-118767(6).)

   * *note email: 3b.: Deprecated the 'isdst' parameter in *note
     email.utils.localtime(): 2c4.  (Contributed by Alan Williams in
     gh-72346(7).)

   * *note importlib.abc: 78. deprecated classes:

        * ‘importlib.abc.ResourceReader’

        * ‘importlib.abc.Traversable’

        * ‘importlib.abc.TraversableResources’

     Use *note importlib.resources.abc: 7c. classes instead:

        * *note importlib.resources.abc.Traversable: 1f3.

        * *note importlib.resources.abc.TraversableResources: 2c5.

     (Contributed by Jason R. Coombs and Hugo van Kemenade in
     gh-93963(8).)

   * *note itertools: 81. had undocumented, inefficient, historically
     buggy, and inconsistent support for copy, deepcopy, and pickle
     operations.  This will be removed in 3.14 for a significant
     reduction in code volume and maintenance burden.  (Contributed by
     Raymond Hettinger in gh-101588(9).)

   * *note multiprocessing: 94.: The default start method will change to
     a safer one on Linux, BSDs, and other non-macOS POSIX platforms
     where ‘'fork'’ is currently the default (gh-84559(10)).  Adding a
     runtime warning about this was deemed too disruptive as the
     majority of code is not expected to care.  Use the *note
     get_context(): 2c6. or *note set_start_method(): 2c7. APIs to
     explicitly specify when your code 'requires' ‘'fork'’.  See *note
     Contexts and start methods: 2c8.

   * *note pathlib: a4.: *note is_relative_to(): 2c9. and *note
     relative_to(): 2ca.: passing additional arguments is deprecated.

   * *note pkgutil: a9.: *note find_loader(): 2cb. and *note
     get_loader(): 2cc. now raise *note DeprecationWarning: 1a5.; use
     *note importlib.util.find_spec(): 2cd. instead.  (Contributed by
     Nikita Sobolev in gh-97850(11).)

   * *note pty: b1.:

        * ‘master_open()’: use *note pty.openpty(): 2ce.

        * ‘slave_open()’: use *note pty.openpty(): 2ce.

   * *note sqlite3: cf.:

        * *note version: 2cf. and *note version_info: 2d0.

        * *note execute(): 2d1. and *note executemany(): 2d2. if *note
          named placeholders: 2d3. are used and 'parameters' is a
          sequence instead of a *note dict: 256.

   * *note urllib: 108.: ‘urllib.parse.Quoter’ is deprecated: it was not
     intended to be a public API. (Contributed by Gregory P. Smith in
     gh-88168(12).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92248

   (2) https://github.com/python/cpython/issues/90953

   (3) https://github.com/python/cpython/issues/94597

   (4) https://github.com/python/cpython/issues/94597

   (5) https://github.com/python/cpython/issues/100160

   (6) https://github.com/python/cpython/issues/118767

   (7) https://github.com/python/cpython/issues/72346

   (8) https://github.com/python/cpython/issues/93963

   (9) https://github.com/python/cpython/issues/101588

   (10) https://github.com/python/cpython/issues/84559

   (11) https://github.com/python/cpython/issues/97850

   (12) https://github.com/python/cpython/issues/88168


File: python.info,  Node: Pending Removal in Python 3 15,  Next: Pending removal in Python 3 16,  Prev: Pending Removal in Python 3 14,  Up: New Deprecations

1.1.8.2 Pending Removal in Python 3.15
......................................

   * The import system:

        * Setting *note __cached__: 2d5. on a module while failing to
          set *note __spec__.cached: 2d6. is deprecated.  In Python
          3.15, ‘__cached__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(1))

        * Setting *note __package__: 2d7. on a module while failing to
          set *note __spec__.parent: 2d8. is deprecated.  In Python
          3.15, ‘__package__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(2))

   * *note ctypes: 2a.:

        * The undocumented ‘ctypes.SetPointerType()’ function has been
          deprecated since Python 3.13.

   * *note http.server: 72.:

        * The obsolete and rarely used *note CGIHTTPRequestHandler: 2a1.
          has been deprecated since Python 3.13.  No direct replacement
          exists.  'Anything' is better than CGI to interface a web
          server with a request handler.

        * The ‘--cgi’ flag to the ‘python -m http.server’ command-line
          interface has been deprecated since Python 3.13.

   * *note importlib: 77.:

        * ‘load_module()’ method: use ‘exec_module()’ instead.

   * *note locale: 86.:

        * The *note getdefaultlocale(): 2d9. function has been
          deprecated since Python 3.11.  Its removal was originally
          planned for Python 3.13 (gh-90817(3)), but has been postponed
          to Python 3.15.  Use *note getlocale(): 2da, *note
          setlocale(): 2db, and *note getencoding(): 2dc. instead.
          (Contributed by Hugo van Kemenade in gh-111187(4).)

   * *note pathlib: a4.:

        * *note PurePath.is_reserved(): 2a6. has been deprecated since
          Python 3.13.  Use *note os.path.isreserved(): 223. to detect
          reserved paths on Windows.

   * *note platform: aa.:

        * *note java_ver(): 2a7. has been deprecated since Python 3.13.
          This function is only useful for Jython support, has a
          confusing API, and is largely untested.

   * *note sysconfig: db.:

        * The 'check_home' argument of *note
          sysconfig.is_python_build(): 2dd. has been deprecated since
          Python 3.12.

   * *note threading: ed.:

        * *note RLock(): 2de. will take no arguments in Python 3.15.
          Passing any arguments has been deprecated since Python 3.14,
          as the Python version does not permit any arguments, but the C
          version allows any number of positional or keyword arguments,
          ignoring every argument.

   * *note types: 103.:

        * *note types.CodeType: 2df.: Accessing *note co_lnotab: 2e0.
          was deprecated in PEP 626(5) since 3.10 and was planned to be
          removed in 3.12, but it only got a proper *note
          DeprecationWarning: 1a5. in 3.12.  May be removed in 3.15.
          (Contributed by Nikita Sobolev in gh-101866(6).)

   * *note typing: 104.:

        * The undocumented keyword argument syntax for creating *note
          NamedTuple: 2b0. classes (e.g.  ‘Point = NamedTuple("Point",
          x=int, y=int)’) has been deprecated since Python 3.13.  Use
          the class-based syntax or the functional syntax instead.

        * When using the functional syntax of *note TypedDict: 162.s,
          failing to pass a value to the 'fields' parameter (‘TD =
          TypedDict("TD")’) or passing ‘None’ (‘TD = TypedDict("TD",
          None)’) has been deprecated since Python 3.13.  Use ‘class
          TD(TypedDict): pass’ or ‘TD = TypedDict("TD", {})’ to create a
          TypedDict with zero field.

        * The *note typing.no_type_check_decorator(): 2b1. decorator
          function has been deprecated since Python 3.13.  After eight
          years in the *note typing: 104. module, it has yet to be
          supported by any major type checker.

   * *note wave: 113.:

        * The *note getmark(): 2b4, ‘setmark()’, and *note getmarkers():
          2b5. methods of the *note Wave_read: 2b6. and *note
          Wave_write: 2b7. classes have been deprecated since Python
          3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97879

   (2) https://github.com/python/cpython/issues/97879

   (3) https://github.com/python/cpython/issues/90817

   (4) https://github.com/python/cpython/issues/111187

   (5) https://peps.python.org/pep-0626/

   (6) https://github.com/python/cpython/issues/101866


File: python.info,  Node: Pending removal in Python 3 16,  Next: Pending removal in Python 3 17,  Prev: Pending Removal in Python 3 15,  Up: New Deprecations

1.1.8.3 Pending removal in Python 3.16
......................................

   * The import system:

        * Setting *note __loader__: 2e2. on a module while failing to
          set *note __spec__.loader: 2e3. is deprecated.  In Python
          3.16, ‘__loader__’ will cease to be set or taken into
          consideration by the import system or the standard library.

   * *note array: 7.:

        * The ‘'u'’ format code (‘wchar_t’) has been deprecated in
          documentation since Python 3.3 and at runtime since Python
          3.13.  Use the ‘'w'’ format code (*note Py_UCS4: 29b.) for
          Unicode characters instead.

   * *note asyncio: a.:

        * ‘asyncio.iscoroutinefunction()’ is deprecated and will be
          removed in Python 3.16, use *note
          inspect.iscoroutinefunction(): 2e4. instead.  (Contributed by
          Jiahao Li and Kumar Aditya in gh-122875(1).)

   * *note builtins: 12.:

        * Bitwise inversion on boolean types, ‘~True’ or ‘~False’ has
          been deprecated since Python 3.12, as it produces surprising
          and unintuitive results (‘-2’ and ‘-1’).  Use ‘not x’ instead
          for the logical negation of a Boolean.  In the rare case that
          you need the bitwise inversion of the underlying integer,
          convert to ‘int’ explicitly (‘~int(x)’).

   * *note shutil: c5.:

        * The ‘ExecError’ exception has been deprecated since Python
          3.14.  It has not been used by any function in ‘shutil’ since
          Python 3.4, and is now an alias of *note RuntimeError: 195.

   * *note symtable: d8.:

        * The *note Class.get_methods: 2e5. method has been deprecated
          since Python 3.14.

   * *note sys: d9.:

        * The *note _enablelegacywindowsfsencoding(): 2ae. function has
          been deprecated since Python 3.13.  Use the *note
          PYTHONLEGACYWINDOWSFSENCODING: 2af. environment variable
          instead.

   * *note tarfile: de.:

        * The undocumented and unused ‘TarFile.tarfile’ attribute has
          been deprecated since Python 3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122875


File: python.info,  Node: Pending removal in Python 3 17,  Next: Pending removal in Python 3 18,  Prev: Pending removal in Python 3 16,  Up: New Deprecations

1.1.8.4 Pending removal in Python 3.17
......................................

   * *note collections.abc: 1e.:

        - *note collections.abc.ByteString: 2e7. is scheduled for
          removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(1) for more details.  (Contributed by Shantanu
          Jain in gh-91896(2).)

   * *note typing: 104.:

        - Before Python 3.14, old-style unions were implemented using
          the private class ‘typing._UnionGenericAlias’.  This class is
          no longer needed for the implementation, but it has been
          retained for backward compatibility, with removal scheduled
          for Python 3.17.  Users should use documented introspection
          helpers like *note typing.get_origin(): 2ec. and *note
          typing.get_args(): 2ed. instead of relying on private
          implementation details.

        - *note typing.ByteString: 2ee, deprecated since Python 3.9, is
          scheduled for removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(3) for more details.  (Contributed by Shantanu
          Jain in gh-91896(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0688/#current-options

   (2) https://github.com/python/cpython/issues/91896

   (3) https://peps.python.org/pep-0688/#current-options

   (4) https://github.com/python/cpython/issues/91896


File: python.info,  Node: Pending removal in Python 3 18,  Next: Pending Removal in Future Versions,  Prev: Pending removal in Python 3 17,  Up: New Deprecations

1.1.8.5 Pending removal in Python 3.18
......................................

   * *note decimal: 36.:

        * The non-standard and undocumented *note Decimal: 29d. format
          specifier ‘'N'’, which is only supported in the ‘decimal’
          module’s C implementation, has been deprecated since Python
          3.13.  (Contributed by Serhiy Storchaka in gh-89902(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89902


File: python.info,  Node: Pending Removal in Future Versions,  Prev: Pending removal in Python 3 18,  Up: New Deprecations

1.1.8.6 Pending Removal in Future Versions
..........................................

The following APIs will be removed in the future, although there is
currently no date scheduled for their removal.

   * *note argparse: 6.: Nesting argument groups and nesting mutually
     exclusive groups are deprecated.

   * *note builtins: 12.:

        * Generators: ‘throw(type, exc, tb)’ and ‘athrow(type, exc, tb)’
          signature is deprecated: use ‘throw(exc)’ and ‘athrow(exc)’
          instead, the single argument signature.

        * Currently Python accepts numeric literals immediately followed
          by keywords, for example ‘0in x’, ‘1or x’, ‘0if 1else 2’.  It
          allows confusing and ambiguous expressions like ‘[0x1for x in
          y]’ (which can be interpreted as ‘[0x1 for x in y]’ or ‘[0x1f
          or x in y]’).  A syntax warning is raised if the numeric
          literal is immediately followed by one of keywords *note and:
          2f1, *note else: 18c, *note for: 2f2, *note if: 2f3, *note in:
          2f4, *note is: 2f5. and *note or: 2f6.  In a future release it
          will be changed to a syntax error.  (gh-87999(1))

        * Support for ‘__index__()’ and ‘__int__()’ method returning
          non-int type: these methods will be required to return an
          instance of a strict subclass of *note int: 257.

        * Support for ‘__float__()’ method returning a strict subclass
          of *note float: 2f7.: these methods will be required to return
          an instance of ‘float’.

        * Support for ‘__complex__()’ method returning a strict subclass
          of *note complex: 2f8.: these methods will be required to
          return an instance of ‘complex’.

        * Delegation of ‘int()’ to ‘__trunc__()’ method.

        * Passing a complex number as the 'real' or 'imag' argument in
          the *note complex(): 2f8. constructor is now deprecated; it
          should only be passed as a single positional argument.
          (Contributed by Serhiy Storchaka in gh-109218(2).)

   * *note calendar: 14.: ‘calendar.January’ and ‘calendar.February’
     constants are deprecated and replaced by *note calendar.JANUARY:
     2f9. and *note calendar.FEBRUARY: 2fa.  (Contributed by Prince
     Roshan in gh-103636(3).)

   * *note codeobject.co_lnotab: 2e0.: use the *note
     codeobject.co_lines(): 2fb. method instead.

   * *note datetime: 30.:

        * *note utcnow(): 2fc.: use
          ‘datetime.datetime.now(tz=datetime.UTC)’.

        * *note utcfromtimestamp(): 2fd.: use
          ‘datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)’.

   * *note gettext: 63.: Plural value must be an integer.

   * *note importlib: 77.:

        * *note cache_from_source(): 2fe. 'debug_override' parameter is
          deprecated: use the 'optimization' parameter instead.

   * *note importlib.metadata: 7a.:

        * ‘EntryPoints’ tuple interface.

        * Implicit ‘None’ on return values.

   * *note logging: 87.: the ‘warn()’ method has been deprecated since
     Python 3.3, use *note warning(): 2ff. instead.

   * *note mailbox: 8b.: Use of StringIO input and text mode is
     deprecated, use BytesIO and binary mode instead.

   * *note os: a1.: Calling *note os.register_at_fork(): 300. in
     multi-threaded process.

   * ‘pydoc.ErrorDuringImport’: A tuple value for 'exc_info' parameter
     is deprecated, use an exception instance.

   * *note re: b9.: More strict rules are now applied for numerical
     group references and group names in regular expressions.  Only
     sequence of ASCII digits is now accepted as a numerical reference.
     The group name in bytes patterns and replacement strings can now
     only contain ASCII letters and digits and underscore.  (Contributed
     by Serhiy Storchaka in gh-91760(4).)

   * ‘sre_compile’, ‘sre_constants’ and ‘sre_parse’ modules.

   * *note shutil: c5.: *note rmtree(): 301.’s 'onerror' parameter is
     deprecated in Python 3.12; use the 'onexc' parameter instead.

   * *note ssl: d0. options and protocols:

        * *note ssl.SSLContext: 294. without protocol argument is
          deprecated.

        * *note ssl.SSLContext: 294.: *note set_npn_protocols(): 302.
          and ‘selected_npn_protocol()’ are deprecated: use ALPN
          instead.

        * ‘ssl.OP_NO_SSL*’ options

        * ‘ssl.OP_NO_TLS*’ options

        * ‘ssl.PROTOCOL_SSLv3’

        * ‘ssl.PROTOCOL_TLS’

        * ‘ssl.PROTOCOL_TLSv1’

        * ‘ssl.PROTOCOL_TLSv1_1’

        * ‘ssl.PROTOCOL_TLSv1_2’

        * ‘ssl.TLSVersion.SSLv3’

        * ‘ssl.TLSVersion.TLSv1’

        * ‘ssl.TLSVersion.TLSv1_1’

   * *note threading: ed. methods:

        * ‘threading.Condition.notifyAll()’: use *note notify_all():
          303.

        * ‘threading.Event.isSet()’: use *note is_set(): 304.

        * ‘threading.Thread.isDaemon()’, *note
          threading.Thread.setDaemon(): 305.: use *note
          threading.Thread.daemon: 306. attribute.

        * ‘threading.Thread.getName()’, *note
          threading.Thread.setName(): 307.: use *note
          threading.Thread.name: 308. attribute.

        * ‘threading.currentThread()’: use *note
          threading.current_thread(): 309.

        * ‘threading.activeCount()’: use *note threading.active_count():
          30a.

   * *note typing.Text: 30b. (gh-92332(5)).

   * *note unittest.IsolatedAsyncioTestCase: 30c.: it is deprecated to
     return a value that is not ‘None’ from a test case.

   * *note urllib.parse: 10a. deprecated functions: *note urlparse():
     30d. instead

        * ‘splitattr()’

        * ‘splithost()’

        * ‘splitnport()’

        * ‘splitpasswd()’

        * ‘splitport()’

        * ‘splitquery()’

        * ‘splittag()’

        * ‘splittype()’

        * ‘splituser()’

        * ‘splitvalue()’

        * ‘to_bytes()’

   * *note urllib.request: 10b.: *note URLopener: 30e. and *note
     FancyURLopener: 30f. style of invoking requests is deprecated.  Use
     newer *note urlopen(): 293. functions and methods.

   * *note wsgiref: 118.: ‘SimpleHandler.stdout.write()’ should not do
     partial writes.

   * *note xml.etree.ElementTree: 125.: Testing the truth value of an
     *note Element: 310. is deprecated.  In a future release it will
     always return ‘True’.  Prefer explicit ‘len(elem)’ or ‘elem is not
     None’ tests instead.

   * *note zipimport.zipimporter.load_module(): 311. is deprecated: use
     *note exec_module(): 312. instead.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87999

   (2) https://github.com/python/cpython/issues/109218

   (3) https://github.com/python/cpython/issues/103636

   (4) https://github.com/python/cpython/issues/91760

   (5) https://github.com/python/cpython/issues/92332


File: python.info,  Node: CPython Bytecode Changes,  Next: C API Changes,  Prev: New Deprecations,  Up: What’s New In Python 3 13

1.1.9 CPython Bytecode Changes
------------------------------

   * The oparg of *note YIELD_VALUE: 314. is now ‘1’ if the yield is
     part of a yield-from or await, and ‘0’ otherwise.  The oparg of
     *note RESUME: 315. was changed to add a bit indicating if the
     except-depth is 1, which is needed to optimize closing of
     generators.  (Contributed by Irit Katriel in gh-111354(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111354


File: python.info,  Node: C API Changes,  Next: Build Changes,  Prev: CPython Bytecode Changes,  Up: What’s New In Python 3 13

1.1.10 C API Changes
--------------------

* Menu:

* New Features: New Features<2>.
* Changed C APIs::
* Limited C API Changes::
* Removed C APIs::
* Deprecated C APIs::


File: python.info,  Node: New Features<2>,  Next: Changed C APIs,  Up: C API Changes

1.1.10.1 New Features
.....................

   * Add the *note PyMonitoring C API: 15c. for generating PEP 669(1)
     monitoring events:

        * *note PyMonitoringState: 318.

        * *note PyMonitoring_FirePyStartEvent(): 319.

        * *note PyMonitoring_FirePyResumeEvent(): 31a.

        * *note PyMonitoring_FirePyReturnEvent(): 31b.

        * *note PyMonitoring_FirePyYieldEvent(): 31c.

        * *note PyMonitoring_FireCallEvent(): 31d.

        * *note PyMonitoring_FireLineEvent(): 31e.

        * *note PyMonitoring_FireJumpEvent(): 31f.

        * *note PyMonitoring_FireBranchEvent(): 320.

        * *note PyMonitoring_FireCReturnEvent(): 321.

        * *note PyMonitoring_FirePyThrowEvent(): 322.

        * *note PyMonitoring_FireRaiseEvent(): 323.

        * *note PyMonitoring_FireCRaiseEvent(): 324.

        * *note PyMonitoring_FireReraiseEvent(): 325.

        * *note PyMonitoring_FireExceptionHandledEvent(): 326.

        * *note PyMonitoring_FirePyUnwindEvent(): 327.

        * *note PyMonitoring_FireStopIterationEvent(): 328.

        * *note PyMonitoring_EnterScope(): 329.

        * *note PyMonitoring_ExitScope(): 32a.

     (Contributed by Irit Katriel in gh-111997(2)).

   * Add *note PyMutex: 15b, a lightweight mutex that occupies a single
     byte, and the new *note PyMutex_Lock(): 32b. and *note
     PyMutex_Unlock(): 32c. functions.  ‘PyMutex_Lock()’ will release
     the *note GIL: 159. (if currently held) if the operation needs to
     block.  (Contributed by Sam Gross in gh-108724(3).)

   * Add the *note PyTime C API: 32d. to provide access to system
     clocks:

        * *note PyTime_t: 32e.

        * *note PyTime_MIN: 32f. and *note PyTime_MAX: 330.

        * *note PyTime_AsSecondsDouble(): 331.

        * *note PyTime_Monotonic(): 332.

        * *note PyTime_MonotonicRaw(): 333.

        * *note PyTime_PerfCounter(): 334.

        * *note PyTime_PerfCounterRaw(): 335.

        * *note PyTime_Time(): 336.

        * *note PyTime_TimeRaw(): 337.

     (Contributed by Victor Stinner and Petr Viktorin in gh-110850(4).)

   * Add the *note PyDict_ContainsString(): 338. function with the same
     behavior as *note PyDict_Contains(): 339, but 'key' is specified as
     a const char* UTF-8 encoded bytes string, rather than a *note
     PyObject: 33a.*.  (Contributed by Victor Stinner in gh-108314(5).)

   * Add the *note PyDict_GetItemRef(): 33b. and *note
     PyDict_GetItemStringRef(): 33c. functions, which behave similarly
     to *note PyDict_GetItemWithError(): 33d, but return a *note strong
     reference: 33e. instead of a *note borrowed reference: 33f.
     Moreover, these functions return ‘-1’ on error, removing the need
     to check ‘PyErr_Occurred()’.  (Contributed by Victor Stinner in
     gh-106004(6).)

   * Add the *note PyDict_SetDefaultRef(): 340. function, which behaves
     similarly to *note PyDict_SetDefault(): 341, but returns a *note
     strong reference: 33e. instead of a *note borrowed reference: 33f.
     This function returns ‘-1’ on error, ‘0’ on insertion, and ‘1’ if
     the key was already present in the dictionary.  (Contributed by Sam
     Gross in gh-112066(7).)

   * Add the *note PyDict_Pop(): 342. and *note PyDict_PopString(): 343.
     functions to remove a key from a dictionary and optionally return
     the removed value.  This is similar to *note dict.pop(): 344,
     though there is no default value, and *note KeyError: 345. is not
     raised for missing keys.  (Contributed by Stefan Behnel and Victor
     Stinner in gh-111262(8).)

   * Add the *note PyMapping_GetOptionalItem(): 346. and *note
     PyMapping_GetOptionalItemString(): 347. functions as alternatives
     to *note PyObject_GetItem(): 348. and *note
     PyMapping_GetItemString(): 349. respectively.  The new functions do
     not raise *note KeyError: 345. if the requested key is missing from
     the mapping.  These variants are more convenient and faster if a
     missing key should not be treated as a failure.  (Contributed by
     Serhiy Storchaka in gh-106307(9).)

   * Add the *note PyObject_GetOptionalAttr(): 34a. and *note
     PyObject_GetOptionalAttrString(): 34b. functions as alternatives to
     *note PyObject_GetAttr(): 34c. and *note PyObject_GetAttrString():
     34d. respectively.  The new functions do not raise *note
     AttributeError: 34e. if the requested attribute is not found on the
     object.  These variants are more convenient and faster if the
     missing attribute should not be treated as a failure.  (Contributed
     by Serhiy Storchaka in gh-106521(10).)

   * Add the *note PyErr_FormatUnraisable(): 34f. function as an
     extension to *note PyErr_WriteUnraisable(): 350. that allows
     customizing the warning message.  (Contributed by Serhiy Storchaka
     in gh-108082(11).)

   * Add new functions that return a *note strong reference: 33e.
     instead of a *note borrowed reference: 33f. for frame locals,
     globals, and builtins, as part of *note PEP 667: 142.:

        * *note PyEval_GetFrameBuiltins(): 351. replaces *note
          PyEval_GetBuiltins(): 352.

        * *note PyEval_GetFrameGlobals(): 353. replaces *note
          PyEval_GetGlobals(): 354.

        * *note PyEval_GetFrameLocals(): 355. replaces *note
          PyEval_GetLocals(): 356.

     (Contributed by Mark Shannon and Tian Gao in gh-74929(12).)

   * Add the *note Py_GetConstant(): 357. and *note
     Py_GetConstantBorrowed(): 358. functions to get *note strong: 33e.
     or *note borrowed: 33f. references to constants.  For example,
     ‘Py_GetConstant(Py_CONSTANT_ZERO)’ returns a strong reference to
     the constant zero.  (Contributed by Victor Stinner in
     gh-115754(13).)

   * Add the *note PyImport_AddModuleRef(): 359. function as a
     replacement for *note PyImport_AddModule(): 35a. that returns a
     *note strong reference: 33e. instead of a *note borrowed reference:
     33f.  (Contributed by Victor Stinner in gh-105922(14).)

   * Add the *note Py_IsFinalizing(): 35b. function to check whether the
     main Python interpreter is *note shutting down: 14e.  (Contributed
     by Victor Stinner in gh-108014(15).)

   * Add the *note PyList_GetItemRef(): 35c. function as a replacement
     for *note PyList_GetItem(): 35d. that returns a *note strong
     reference: 33e. instead of a *note borrowed reference: 33f.
     (Contributed by Sam Gross in gh-114329(16).)

   * Add the *note PyList_Extend(): 35e. and *note PyList_Clear(): 35f.
     functions, mirroring the Python *note list.extend(): 360. and *note
     list.clear(): 361. methods.  (Contributed by Victor Stinner in
     gh-111138(17).)

   * Add the *note PyLong_AsInt(): 362. function.  It behaves similarly
     to *note PyLong_AsLong(): 363, but stores the result in a C int
     instead of a C long.  (Contributed by Victor Stinner in
     gh-108014(18).)

   * Add the *note PyLong_AsNativeBytes(): 364, *note
     PyLong_FromNativeBytes(): 365, and *note
     PyLong_FromUnsignedNativeBytes(): 366. functions to simplify
     converting between native integer types and Python *note int: 257.
     objects.  (Contributed by Steve Dower in gh-111140(19).)

   * Add *note PyModule_Add(): 367. function, which is similar to *note
     PyModule_AddObjectRef(): 368. and *note PyModule_AddObject(): 369,
     but always steals a reference to the value.  (Contributed by Serhiy
     Storchaka in gh-86493(20).)

   * Add the *note PyObject_GenericHash(): 36a. function that implements
     the default hashing function of a Python object.  (Contributed by
     Serhiy Storchaka in gh-113024(21).)

   * Add the *note Py_HashPointer(): 36b. function to hash a raw
     pointer.  (Contributed by Victor Stinner in gh-111545(22).)

   * Add the *note PyObject_VisitManagedDict(): 36c. and *note
     PyObject_ClearManagedDict(): 36d. functions.  which must be called
     by the traverse and clear functions of a type using the *note
     Py_TPFLAGS_MANAGED_DICT: 36e. flag.  The pythoncapi-compat
     project(23) can be used to use these functions with Python 3.11 and
     3.12.  (Contributed by Victor Stinner in gh-107073(24).)

   * Add the *note PyRefTracer_SetTracer(): 36f. and *note
     PyRefTracer_GetTracer(): 370. functions, which enable tracking
     object creation and destruction in the same way that the *note
     tracemalloc: ff. module does.  (Contributed by Pablo Galindo in
     gh-93502(25).)

   * Add the *note PySys_AuditTuple(): 371. function as an alternative
     to *note PySys_Audit(): 372. that takes event arguments as a Python
     *note tuple: 373. object.  (Contributed by Victor Stinner in
     gh-85283(26).)

   * Add the *note PyThreadState_GetUnchecked(): 374. function as an
     alternative to *note PyThreadState_Get(): 375. that doesn’t kill
     the process with a fatal error if it is ‘NULL’.  The caller is
     responsible for checking if the result is ‘NULL’.  (Contributed by
     Victor Stinner in gh-108867(27).)

   * Add the *note PyType_GetFullyQualifiedName(): 376. function to get
     the type’s fully qualified name.  The module name is prepended if
     *note type.__module__: 377. is a string and is not equal to either
     ‘'builtins'’ or ‘'__main__'’.  (Contributed by Victor Stinner in
     gh-111696(28).)

   * Add the *note PyType_GetModuleName(): 378. function to get the
     type’s module name.  This is equivalent to getting the *note
     type.__module__: 377. attribute.  (Contributed by Eric Snow and
     Victor Stinner in gh-111696(29).)

   * Add the *note PyUnicode_EqualToUTF8AndSize(): 379. and *note
     PyUnicode_EqualToUTF8(): 37a. functions to compare a Unicode object
     with a const char* UTF-8 encoded string and ‘1’ if they are equal
     or ‘0’ otherwise.  These functions do not raise exceptions.
     (Contributed by Serhiy Storchaka in gh-110289(30).)

   * Add the *note PyWeakref_GetRef(): 37b. function as an alternative
     to *note PyWeakref_GetObject(): 37c. that returns a *note strong
     reference: 33e. or ‘NULL’ if the referent is no longer live.
     (Contributed by Victor Stinner in gh-105927(31).)

   * Add fixed variants of functions which silently ignore errors:

        * *note PyObject_HasAttrWithError(): 37d. replaces *note
          PyObject_HasAttr(): 37e.

        * *note PyObject_HasAttrStringWithError(): 37f. replaces *note
          PyObject_HasAttrString(): 380.

        * *note PyMapping_HasKeyWithError(): 381. replaces *note
          PyMapping_HasKey(): 382.

        * *note PyMapping_HasKeyStringWithError(): 383. replaces *note
          PyMapping_HasKeyString(): 384.

     The new functions return ‘-1’ for errors and the standard ‘1’ for
     true and ‘0’ for false.

     (Contributed by Serhiy Storchaka in gh-108511(32).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0669/

   (2) https://github.com/python/cpython/issues/111997

   (3) https://github.com/python/cpython/issues/108724

   (4) https://github.com/python/cpython/issues/110850

   (5) https://github.com/python/cpython/issues/108314

   (6) https://github.com/python/cpython/issues/106004

   (7) https://github.com/python/cpython/issues/112066

   (8) https://github.com/python/cpython/issues/111262

   (9) https://github.com/python/cpython/issues/106307

   (10) https://github.com/python/cpython/issues/106521

   (11) https://github.com/python/cpython/issues/108082

   (12) https://github.com/python/cpython/issues/74929

   (13) https://github.com/python/cpython/issues/115754

   (14) https://github.com/python/cpython/issues/105922

   (15) https://github.com/python/cpython/issues/108014

   (16) https://github.com/python/cpython/issues/114329

   (17) https://github.com/python/cpython/issues/111138

   (18) https://github.com/python/cpython/issues/108014

   (19) https://github.com/python/cpython/issues/111140

   (20) https://github.com/python/cpython/issues/86493

   (21) https://github.com/python/cpython/issues/113024

   (22) https://github.com/python/cpython/issues/111545

   (23) https://github.com/python/pythoncapi-compat/

   (24) https://github.com/python/cpython/issues/107073

   (25) https://github.com/python/cpython/issues/93502

   (26) https://github.com/python/cpython/issues/85283

   (27) https://github.com/python/cpython/issues/108867

   (28) https://github.com/python/cpython/issues/111696

   (29) https://github.com/python/cpython/issues/111696

   (30) https://github.com/python/cpython/issues/110289

   (31) https://github.com/python/cpython/issues/105927

   (32) https://github.com/python/cpython/issues/108511


File: python.info,  Node: Changed C APIs,  Next: Limited C API Changes,  Prev: New Features<2>,  Up: C API Changes

1.1.10.2 Changed C APIs
.......................

   * The 'keywords' parameter of *note PyArg_ParseTupleAndKeywords():
     386. and *note PyArg_VaParseTupleAndKeywords(): 387. now has type
     char *const* in C and const char *const* in C++, instead of char**.
     In C++, this makes these functions compatible with arguments of
     type const char *const*, const char**, or char *const* without an
     explicit type cast.  In C, the functions only support arguments of
     type char *const*.  This can be overridden with the *note
     PY_CXX_CONST: 388. macro.  (Contributed by Serhiy Storchaka in
     gh-65210(1).)

   * *note PyArg_ParseTupleAndKeywords(): 386. now supports non-ASCII
     keyword parameter names.  (Contributed by Serhiy Storchaka in
     gh-110815(2).)

   * The ‘PyCode_GetFirstFree()’ function is now unstable API and is now
     named *note PyUnstable_Code_GetFirstFree(): 389.  (Contributed by
     Bogdan Romanyuk in gh-115781(3).)

   * The *note PyDict_GetItem(): 38a, *note PyDict_GetItemString(): 38b,
     *note PyMapping_HasKey(): 382, *note PyMapping_HasKeyString(): 384,
     *note PyObject_HasAttr(): 37e, *note PyObject_HasAttrString(): 380,
     and *note PySys_GetObject(): 38c. functions, each of which clears
     all errors which occurred when calling them now reports these
     errors using *note sys.unraisablehook(): 1f7.  You may replace them
     with other functions as recommended in the documentation.
     (Contributed by Serhiy Storchaka in gh-106672(4).)

   * Add support for the ‘%T’, ‘%#T’, ‘%N’ and ‘%#N’ formats to *note
     PyUnicode_FromFormat(): 38d.:

        * ‘%T’: Get the fully qualified name of an object type

        * ‘%#T’: As above, but use a colon as the separator

        * ‘%N’: Get the fully qualified name of a type

        * ‘%#N’: As above, but use a colon as the separator

     See PEP 737(5) for more information.  (Contributed by Victor
     Stinner in gh-111696(6).)

   * You no longer have to define the ‘PY_SSIZE_T_CLEAN’ macro before
     including ‘Python.h’ when using ‘#’ formats in *note format codes:
     38e.  APIs accepting the format codes always use ‘Py_ssize_t’ for
     ‘#’ formats.  (Contributed by Inada Naoki in gh-104922(7).)

   * If Python is built in *note debug mode: 1f9. or *note with
     assertions: 38f, *note PyTuple_SET_ITEM(): 390. and *note
     PyList_SET_ITEM(): 391. now check the index argument with an
     assertion.  (Contributed by Victor Stinner in gh-106168(8).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/65210

   (2) https://github.com/python/cpython/issues/110815

   (3) https://github.com/python/cpython/issues/115781

   (4) https://github.com/python/cpython/issues/106672

   (5) https://peps.python.org/pep-0737/

   (6) https://github.com/python/cpython/issues/111696

   (7) https://github.com/python/cpython/issues/104922

   (8) https://github.com/python/cpython/issues/106168


File: python.info,  Node: Limited C API Changes,  Next: Removed C APIs,  Prev: Changed C APIs,  Up: C API Changes

1.1.10.3 Limited C API Changes
..............................

   * The following functions are now included in the Limited C API:

        * *note PyMem_RawMalloc(): 393.

        * *note PyMem_RawCalloc(): 394.

        * *note PyMem_RawRealloc(): 395.

        * *note PyMem_RawFree(): 396.

        * *note PySys_Audit(): 372.

        * *note PySys_AuditTuple(): 371.

        * *note PyType_GetModuleByDef(): 397.

     (Contributed by Victor Stinner in gh-85283(1) and gh-116936(2).)

   * Python built with *note -with-trace-refs: 398. (tracing references)
     now supports the *note Limited API: 399.  (Contributed by Victor
     Stinner in gh-108634(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/85283

   (2) https://github.com/python/cpython/issues/116936

   (3) https://github.com/python/cpython/issues/108634


File: python.info,  Node: Removed C APIs,  Next: Deprecated C APIs,  Prev: Limited C API Changes,  Up: C API Changes

1.1.10.4 Removed C APIs
.......................

   * Remove several functions, macros, variables, etc with names
     prefixed by ‘_Py’ or ‘_PY’ (which are considered private).  If your
     project is affected by one of these removals and you believe that
     the removed API should remain available, please *note open a new
     issue: 24e. to request a public C API and add ‘cc: @vstinner’ to
     the issue to notify Victor Stinner.  (Contributed by Victor Stinner
     in gh-106320(1).)

   * Remove old buffer protocols deprecated in Python 3.0.  Use *note
     Buffer Protocol: 2e8. instead.

        * ‘PyObject_CheckReadBuffer()’: Use *note
          PyObject_CheckBuffer(): 39b. to test whether the object
          supports the buffer protocol.  Note that
          ‘PyObject_CheckBuffer()’ doesn’t guarantee that *note
          PyObject_GetBuffer(): 39c. will succeed.  To test if the
          object is actually readable, see the next example of
          ‘PyObject_GetBuffer()’.

        * ‘PyObject_AsCharBuffer()’, ‘PyObject_AsReadBuffer()’: Use
          *note PyObject_GetBuffer(): 39c. and *note PyBuffer_Release():
          39d. instead:

               Py_buffer view;
               if (PyObject_GetBuffer(obj, &view, PyBUF_SIMPLE) < 0) {
                   return NULL;
               }
               // Use `view.buf` and `view.len` to read from the buffer.
               // You may need to cast buf as `(const char*)view.buf`.
               PyBuffer_Release(&view);

        * ‘PyObject_AsWriteBuffer()’: Use *note PyObject_GetBuffer():
          39c. and *note PyBuffer_Release(): 39d. instead:

               Py_buffer view;
               if (PyObject_GetBuffer(obj, &view, PyBUF_WRITABLE) < 0) {
                   return NULL;
               }
               // Use `view.buf` and `view.len` to write to the buffer.
               PyBuffer_Release(&view);

     (Contributed by Inada Naoki in gh-85275(2).)

   * Remove various functions deprecated in Python 3.9:

        * ‘PyEval_CallObject()’, ‘PyEval_CallObjectWithKeywords()’: Use
          *note PyObject_CallNoArgs(): 39e. or *note PyObject_Call():
          39f. instead.

               Warning: In *note PyObject_Call(): 39f, positional
               arguments must be a *note tuple: 373. and must not be
               ‘NULL’, and keyword arguments must be a *note dict: 256.
               or ‘NULL’, whereas the removed functions checked argument
               types and accepted ‘NULL’ positional and keyword
               arguments.  To replace
               ‘PyEval_CallObjectWithKeywords(func, NULL, kwargs)’ with
               ‘PyObject_Call()’, pass an empty tuple as positional
               arguments using *note PyTuple_New(0): 3a0.

        * ‘PyEval_CallFunction()’: Use *note PyObject_CallFunction():
          3a1. instead.

        * ‘PyEval_CallMethod()’: Use *note PyObject_CallMethod(): 3a2.
          instead.

        * ‘PyCFunction_Call()’: Use *note PyObject_Call(): 39f. instead.

     (Contributed by Victor Stinner in gh-105107(3).)

   * Remove the following old functions to configure the Python
     initialization, deprecated in Python 3.11:

        * ‘PySys_AddWarnOptionUnicode()’: Use *note
          PyConfig.warnoptions: 3a3. instead.

        * ‘PySys_AddWarnOption()’: Use *note PyConfig.warnoptions: 3a3.
          instead.

        * ‘PySys_AddXOption()’: Use *note PyConfig.xoptions: 3a4.
          instead.

        * ‘PySys_HasWarnOptions()’: Use *note PyConfig.xoptions: 3a4.
          instead.

        * ‘PySys_SetPath()’: Set *note PyConfig.module_search_paths:
          3a5. instead.

        * ‘Py_SetPath()’: Set *note PyConfig.module_search_paths: 3a5.
          instead.

        * ‘Py_SetStandardStreamEncoding()’: Set *note
          PyConfig.stdio_encoding: 3a6. instead, and set also maybe
          *note PyConfig.legacy_windows_stdio: 3a7. (on Windows).

        * ‘_Py_SetProgramFullPath()’: Set *note PyConfig.executable:
          3a8. instead.

     Use the new *note PyConfig: 3a9. API of the *note Python
     Initialization Configuration: 3aa. instead ( PEP 587(4)), added to
     Python 3.8.  (Contributed by Victor Stinner in gh-105145(5).)

   * Remove ‘PyEval_AcquireLock()’ and ‘PyEval_ReleaseLock()’ functions,
     deprecated in Python 3.2.  They didn’t update the current thread
     state.  They can be replaced with:

        * *note PyEval_SaveThread(): 3ab. and *note
          PyEval_RestoreThread(): 3ac.;

        * low-level *note PyEval_AcquireThread(): 3ad. and *note
          PyEval_RestoreThread(): 3ac.;

        * or *note PyGILState_Ensure(): 3ae. and *note
          PyGILState_Release(): 3af.

     (Contributed by Victor Stinner in gh-105182(6).)

   * Remove the ‘PyEval_ThreadsInitialized()’ function, deprecated in
     Python 3.9.  Since Python 3.7, ‘Py_Initialize()’ always creates the
     GIL: calling ‘PyEval_InitThreads()’ does nothing and
     ‘PyEval_ThreadsInitialized()’ always returns non-zero.
     (Contributed by Victor Stinner in gh-105182(7).)

   * Remove the ‘_PyInterpreterState_Get()’ alias to *note
     PyInterpreterState_Get(): 3b0. which was kept for backward
     compatibility with Python 3.8.  The pythoncapi-compat project(8)
     can be used to get ‘PyInterpreterState_Get()’ on Python 3.8 and
     older.  (Contributed by Victor Stinner in gh-106320(9).)

   * Remove the private ‘_PyObject_FastCall()’ function: use
     ‘PyObject_Vectorcall()’ which is available since Python 3.8 ( PEP
     590(10)).  (Contributed by Victor Stinner in gh-106023(11).)

   * Remove the ‘cpython/pytime.h’ header file, which only contained
     private functions.  (Contributed by Victor Stinner in
     gh-106316(12).)

   * Remove the undocumented ‘PY_TIMEOUT_MAX’ constant from the limited
     C API. (Contributed by Victor Stinner in gh-110014(13).)

   * Remove the old trashcan macros ‘Py_TRASHCAN_SAFE_BEGIN’ and
     ‘Py_TRASHCAN_SAFE_END’.  Replace both with the new macros
     ‘Py_TRASHCAN_BEGIN’ and ‘Py_TRASHCAN_END’.  (Contributed by Irit
     Katriel in gh-105111(14).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/106320

   (2) https://github.com/python/cpython/issues/85275

   (3) https://github.com/python/cpython/issues/105107

   (4) https://peps.python.org/pep-0587/

   (5) https://github.com/python/cpython/issues/105145

   (6) https://github.com/python/cpython/issues/105182

   (7) https://github.com/python/cpython/issues/105182

   (8) https://github.com/python/pythoncapi-compat/

   (9) https://github.com/python/cpython/issues/106320

   (10) https://peps.python.org/pep-0590/

   (11) https://github.com/python/cpython/issues/106023

   (12) https://github.com/python/cpython/issues/106316

   (13) https://github.com/python/cpython/issues/110014

   (14) https://github.com/python/cpython/issues/105111


File: python.info,  Node: Deprecated C APIs,  Prev: Removed C APIs,  Up: C API Changes

1.1.10.5 Deprecated C APIs
..........................

   * Deprecate old Python initialization functions:

        * *note PySys_ResetWarnOptions(): 3b2.: Clear *note
          sys.warnoptions: 3b3. and ‘warnings.filters’ instead.

        * *note Py_GetExecPrefix(): 3b4.: Get *note sys.exec_prefix:
          3b5. instead.

        * *note Py_GetPath(): 3b6.: Get *note sys.path: 3b7. instead.

        * *note Py_GetPrefix(): 3b8.: Get *note sys.prefix: 3b9.
          instead.

        * *note Py_GetProgramFullPath(): 3ba.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetProgramName(): 3bc.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetPythonHome(): 3bd.: Get *note PyConfig.home: 3be.
          or the *note PYTHONHOME: 3bf. environment variable instead.

     (Contributed by Victor Stinner in gh-105145(1).)

   * *note Soft deprecate: 209. the *note PyEval_GetBuiltins(): 352,
     *note PyEval_GetGlobals(): 354, and *note PyEval_GetLocals(): 356.
     functions, which return a *note borrowed reference: 33f.  (Soft
     deprecated as part of PEP 667(2).)

   * Deprecate the *note PyImport_ImportModuleNoBlock(): 3c0. function,
     which is just an alias to *note PyImport_ImportModule(): 3c1. since
     Python 3.3.  (Contributed by Victor Stinner in gh-105396(3).)

   * *note Soft deprecate: 209. the *note PyModule_AddObject(): 369.
     function.  It should be replaced with *note PyModule_Add(): 367. or
     *note PyModule_AddObjectRef(): 368.  (Contributed by Serhiy
     Storchaka in gh-86493(4).)

   * Deprecate the old ‘Py_UNICODE’ and ‘PY_UNICODE_TYPE’ types and the
     ‘Py_UNICODE_WIDE’ define.  Use the ‘wchar_t’ type directly instead.
     Since Python 3.3, ‘Py_UNICODE’ and ‘PY_UNICODE_TYPE’ are just
     aliases to ‘wchar_t’.  (Contributed by Victor Stinner in
     gh-105156(5).)

   * Deprecate the *note PyWeakref_GetObject(): 37c. and *note
     PyWeakref_GET_OBJECT(): 3c2. functions, which return a *note
     borrowed reference: 33f.  Replace them with the new *note
     PyWeakref_GetRef(): 37b. function, which returns a *note strong
     reference: 33e.  The pythoncapi-compat project(6) can be used to
     get ‘PyWeakref_GetRef()’ on Python 3.12 and older.  (Contributed by
     Victor Stinner in gh-105927(7).)

* Menu:

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<2>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<2>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105145

   (2) https://peps.python.org/pep-0667/

   (3) https://github.com/python/cpython/issues/105396

   (4) https://github.com/python/cpython/issues/86493

   (5) https://github.com/python/cpython/issues/105156

   (6) https://github.com/python/pythoncapi-compat/

   (7) https://github.com/python/cpython/issues/105927


File: python.info,  Node: Pending Removal in Python 3 14<2>,  Next: Pending Removal in Python 3 15<2>,  Up: Deprecated C APIs

1.1.10.6 Pending Removal in Python 3.14
.......................................

   * The ‘ma_version_tag’ field in *note PyDictObject: 3c4. for
     extension modules ( PEP 699(1); gh-101193(2)).

   * Creating *note immutable types: 3c5. with mutable bases
     (gh-95388(3)).

   * Functions to configure Python’s initialization, deprecated in
     Python 3.11:

        * ‘PySys_SetArgvEx()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘PySys_SetArgv()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘Py_SetProgramName()’: Set *note PyConfig.program_name: 3c7.
          instead.

        * ‘Py_SetPythonHome()’: Set *note PyConfig.home: 3be. instead.

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   * Global configuration variables:

        * *note Py_DebugFlag: 3c9.: Use *note PyConfig.parser_debug:
          3ca. instead.

        * *note Py_VerboseFlag: 3cb.: Use *note PyConfig.verbose: 3cc.
          instead.

        * *note Py_QuietFlag: 3cd.: Use *note PyConfig.quiet: 3ce.
          instead.

        * *note Py_InteractiveFlag: 3cf.: Use *note
          PyConfig.interactive: 3d0. instead.

        * *note Py_InspectFlag: 3d1.: Use *note PyConfig.inspect: 3d2.
          instead.

        * *note Py_OptimizeFlag: 3d3.: Use *note
          PyConfig.optimization_level: 3d4. instead.

        * *note Py_NoSiteFlag: 3d5.: Use *note PyConfig.site_import:
          3d6. instead.

        * *note Py_BytesWarningFlag: 3d7.: Use *note
          PyConfig.bytes_warning: 3d8. instead.

        * *note Py_FrozenFlag: 3d9.: Use *note
          PyConfig.pathconfig_warnings: 3da. instead.

        * *note Py_IgnoreEnvironmentFlag: 3db.: Use *note
          PyConfig.use_environment: 3dc. instead.

        * *note Py_DontWriteBytecodeFlag: 3dd.: Use *note
          PyConfig.write_bytecode: 3de. instead.

        * *note Py_NoUserSiteDirectory: 3df.: Use *note
          PyConfig.user_site_directory: 3e0. instead.

        * *note Py_UnbufferedStdioFlag: 3e1.: Use *note
          PyConfig.buffered_stdio: 3e2. instead.

        * *note Py_HashRandomizationFlag: 3e3.: Use *note
          PyConfig.use_hash_seed: 3e4. and *note PyConfig.hash_seed:
          3e5. instead.

        * *note Py_IsolatedFlag: 3e6.: Use *note PyConfig.isolated: 3e7.
          instead.

        * *note Py_LegacyWindowsFSEncodingFlag: 3e8.: Use *note
          PyPreConfig.legacy_windows_fs_encoding: 3e9. instead.

        * *note Py_LegacyWindowsStdioFlag: 3ea.: Use *note
          PyConfig.legacy_windows_stdio: 3a7. instead.

        * ‘Py_FileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_HasFileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_FileSystemDefaultEncodeErrors’: Use *note
          PyConfig.filesystem_errors: 3ec. instead.

        * ‘Py_UTF8Mode’: Use *note PyPreConfig.utf8_mode: 3ed. instead.
          (see *note Py_PreInitialize(): 3ee.)

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0699/

   (2) https://github.com/python/cpython/issues/101193

   (3) https://github.com/python/cpython/issues/95388


File: python.info,  Node: Pending Removal in Python 3 15<2>,  Next: Pending removal in Python 3 16<2>,  Prev: Pending Removal in Python 3 14<2>,  Up: Deprecated C APIs

1.1.10.7 Pending Removal in Python 3.15
.......................................

   * The *note PyImport_ImportModuleNoBlock(): 3c0.: Use *note
     PyImport_ImportModule(): 3c1. instead.

   * *note PyWeakref_GetObject(): 37c. and *note PyWeakref_GET_OBJECT():
     3c2.: Use *note PyWeakref_GetRef(): 37b. instead.

   * *note Py_UNICODE: 3f0. type and the ‘Py_UNICODE_WIDE’ macro: Use
     ‘wchar_t’ instead.

   * Python initialization functions:

        * *note PySys_ResetWarnOptions(): 3b2.: Clear *note
          sys.warnoptions: 3b3. and ‘warnings.filters’ instead.

        * *note Py_GetExecPrefix(): 3b4.: Get *note
          sys.base_exec_prefix: 3f1. and *note sys.exec_prefix: 3b5.
          instead.

        * *note Py_GetPath(): 3b6.: Get *note sys.path: 3b7. instead.

        * *note Py_GetPrefix(): 3b8.: Get *note sys.base_prefix: 3f2.
          and *note sys.prefix: 3b9. instead.

        * *note Py_GetProgramFullPath(): 3ba.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetProgramName(): 3bc.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetPythonHome(): 3bd.: Get *note PyConfig.home: 3be.
          or the *note PYTHONHOME: 3bf. environment variable instead.


File: python.info,  Node: Pending removal in Python 3 16<2>,  Next: Pending Removal in Future Versions<2>,  Prev: Pending Removal in Python 3 15<2>,  Up: Deprecated C APIs

1.1.10.8 Pending removal in Python 3.16
.......................................

   * The bundled copy of ‘libmpdec’.


File: python.info,  Node: Pending Removal in Future Versions<2>,  Prev: Pending removal in Python 3 16<2>,  Up: Deprecated C APIs

1.1.10.9 Pending Removal in Future Versions
...........................................

The following APIs are deprecated and will be removed, although there is
currently no date scheduled for their removal.

   * *note Py_TPFLAGS_HAVE_FINALIZE: 3f5.: Unneeded since Python 3.8.

   * *note PyErr_Fetch(): 3f6.: Use *note PyErr_GetRaisedException():
     3f7. instead.

   * *note PyErr_NormalizeException(): 3f8.: Use *note
     PyErr_GetRaisedException(): 3f7. instead.

   * *note PyErr_Restore(): 3f9.: Use *note PyErr_SetRaisedException():
     3fa. instead.

   * *note PyModule_GetFilename(): 3fb.: Use *note
     PyModule_GetFilenameObject(): 3fc. instead.

   * *note PyOS_AfterFork(): 3fd.: Use *note PyOS_AfterFork_Child():
     3fe. instead.

   * *note PySlice_GetIndicesEx(): 3ff.: Use *note PySlice_Unpack():
     400. and *note PySlice_AdjustIndices(): 401. instead.

   * ‘PyUnicode_AsDecodedObject()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsDecodedUnicode()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsEncodedObject()’: Use *note PyCodec_Encode(): 403.
     instead.

   * ‘PyUnicode_AsEncodedUnicode()’: Use *note PyCodec_Encode(): 403.
     instead.

   * *note PyUnicode_READY(): 404.: Unneeded since Python 3.12

   * ‘PyErr_Display()’: Use *note PyErr_DisplayException(): 405.
     instead.

   * ‘_PyErr_ChainExceptions()’: Use ‘_PyErr_ChainExceptions1()’
     instead.

   * ‘PyBytesObject.ob_shash’ member: call *note PyObject_Hash(): 406.
     instead.

   * ‘PyDictObject.ma_version_tag’ member.

   * Thread Local Storage (TLS) API:

        * *note PyThread_create_key(): 407.: Use *note
          PyThread_tss_alloc(): 408. instead.

        * *note PyThread_delete_key(): 409.: Use *note
          PyThread_tss_free(): 40a. instead.

        * *note PyThread_set_key_value(): 40b.: Use *note
          PyThread_tss_set(): 40c. instead.

        * *note PyThread_get_key_value(): 40d.: Use *note
          PyThread_tss_get(): 40e. instead.

        * *note PyThread_delete_key_value(): 40f.: Use *note
          PyThread_tss_delete(): 410. instead.

        * *note PyThread_ReInitTLS(): 411.: Unneeded since Python 3.7.


File: python.info,  Node: Build Changes,  Next: Porting to Python 3 13,  Prev: C API Changes,  Up: What’s New In Python 3 13

1.1.11 Build Changes
--------------------

   * ‘arm64-apple-ios’ and ‘arm64-apple-ios-simulator’ are both now PEP
     11(1) tier 3 platforms.  (*note PEP 730: 165. written and
     implementation contributed by Russell Keith-Magee in gh-114099(2).)

   * ‘aarch64-linux-android’ and ‘x86_64-linux-android’ are both now PEP
     11(3) tier 3 platforms.  (*note PEP 738: 165. written and
     implementation contributed by Malcolm Smith in gh-116622(4).)

   * ‘wasm32-wasi’ is now a PEP 11(5) tier 2 platform.  (Contributed by
     Brett Cannon in gh-115192(6).)

   * ‘wasm32-emscripten’ is no longer a PEP 11(7) supported platform.
     (Contributed by Brett Cannon in gh-115192(8).)

   * Building CPython now requires a compiler with support for the C11
     atomic library, GCC built-in atomic functions, or MSVC interlocked
     intrinsics.

   * Autoconf 2.71 and aclocal 1.16.5 are now required to regenerate the
     ‘configure’ script.  (Contributed by Christian Heimes in
     gh-89886(9) and by Victor Stinner in gh-112090(10).)

   * SQLite 3.15.2 or newer is required to build the *note sqlite3: cf.
     extension module.  (Contributed by Erlend Aasland in
     gh-105875(11).)

   * CPython now bundles the mimalloc library(12) by default.  It is
     licensed under the MIT license; see *note mimalloc license: 414.
     The bundled mimalloc has custom changes, see gh-113141(13) for
     details.  (Contributed by Dino Viehland in gh-109914(14).)

   * The ‘configure’ option *note -with-system-libmpdec: 415. now
     defaults to ‘yes’.  The bundled copy of ‘libmpdec’ will be removed
     in Python 3.16.

   * Python built with ‘configure’ *note -with-trace-refs: 398. (tracing
     references) is now ABI compatible with the Python release build and
     *note debug build: 1f9.  (Contributed by Victor Stinner in
     gh-108634(15).)

   * On POSIX systems, the pkg-config (‘.pc’) filenames now include the
     ABI flags.  For example, the free-threaded build generates
     ‘python-3.13t.pc’ and the debug build generates ‘python-3.13d.pc’.

   * The ‘errno’, ‘fcntl’, ‘grp’, ‘md5’, ‘pwd’, ‘resource’, ‘termios’,
     ‘winsound’, ‘_ctypes_test’, ‘_multiprocessing.posixshmem’,
     ‘_scproxy’, ‘_stat’, ‘_statistics’, ‘_testconsole’,
     ‘_testimportmultiple’ and ‘_uuid’ C extensions are now built with
     the *note limited C API: 399.  (Contributed by Victor Stinner in
     gh-85283(16).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0011/

   (2) https://github.com/python/cpython/issues/114099

   (3) https://peps.python.org/pep-0011/

   (4) https://github.com/python/cpython/issues/116622

   (5) https://peps.python.org/pep-0011/

   (6) https://github.com/python/cpython/issues/115192

   (7) https://peps.python.org/pep-0011/

   (8) https://github.com/python/cpython/issues/115192

   (9) https://github.com/python/cpython/issues/89886

   (10) https://github.com/python/cpython/issues/112090

   (11) https://github.com/python/cpython/issues/105875

   (12) https://github.com/microsoft/mimalloc/

   (13) https://github.com/python/cpython/issues/113141

   (14) https://github.com/python/cpython/issues/109914

   (15) https://github.com/python/cpython/issues/108634

   (16) https://github.com/python/cpython/issues/85283


File: python.info,  Node: Porting to Python 3 13,  Next: Regression Test Changes,  Prev: Build Changes,  Up: What’s New In Python 3 13

1.1.12 Porting to Python 3.13
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in the Python API::
* Changes in the C API::


File: python.info,  Node: Changes in the Python API,  Next: Changes in the C API,  Up: Porting to Python 3 13

1.1.12.1 Changes in the Python API
..................................

   * *note PEP 667: 142. introduces several changes to the semantics of
     *note locals(): 141. and *note f_locals: 182.:

        * Calling *note locals(): 141. in an *note optimized scope: 17e.
          now produces an independent snapshot on each call, and hence
          no longer implicitly updates previously returned references.
          Obtaining the legacy CPython behavior now requires explicit
          calls to update the initially returned dictionary with the
          results of subsequent calls to ‘locals()’.  Code execution
          functions that implicitly target ‘locals()’ (such as ‘exec’
          and ‘eval’) must be passed an explicit namespace to access
          their results in an optimized scope.  (Changed as part of PEP
          667(1).)

        * Calling *note locals(): 141. from a comprehension at module or
          class scope (including via ‘exec’ or ‘eval’) once more behaves
          as if the comprehension were running as an independent nested
          function (i.e.  the local variables from the containing scope
          are not included).  In Python 3.12, this had changed to
          include the local variables from the containing scope when
          implementing PEP 709(2).  (Changed as part of PEP 667(3).)

        * Accessing *note FrameType.f_locals: 182. in an *note optimized
          scope: 17e. now returns a write-through proxy rather than a
          snapshot that gets updated at ill-specified times.  If a
          snapshot is desired, it must be created explicitly with ‘dict’
          or the proxy’s ‘.copy()’ method.  (Changed as part of PEP
          667(4).)

   * *note functools.partial: 417. now emits a *note FutureWarning: 418.
     when used as a method.  The behavior will change in future Python
     versions.  Wrap it in *note staticmethod(): 419. if you want to
     preserve the old behavior.  (Contributed by Serhiy Storchaka in
     gh-121027(5).)

   * An *note OSError: 41a. is now raised by *note getpass.getuser():
     41b. for any failure to retrieve a username, instead of *note
     ImportError: 41c. on non-Unix platforms or *note KeyError: 345. on
     Unix platforms where the password database is empty.

   * The value of the ‘mode’ attribute of *note gzip.GzipFile: 41d. is
     now a string (‘'rb'’ or ‘'wb'’) instead of an integer (‘1’ or ‘2’).
     The value of the ‘mode’ attribute of the readable file-like object
     returned by *note zipfile.ZipFile.open(): 41e. is now ‘'rb'’
     instead of ‘'r'’.  (Contributed by Serhiy Storchaka in
     gh-115961(6).)

   * *note mailbox.Maildir: 41f. now ignores files with a leading dot
     (‘.’).  (Contributed by Zackery Spytz in gh-65559(7).)

   * *note pathlib.Path.glob(): 22d. and *note rglob(): 22e. now return
     both files and directories if a pattern that ends with “‘**’” is
     given, rather than directories only.  Add a trailing slash to keep
     the previous behavior and only match directories.

   * The *note threading: ed. module now expects the ‘_thread’ module to
     have an ‘_is_main_interpreter()’ function.  This function takes no
     arguments and returns ‘True’ if the current interpreter is the main
     interpreter.

     Any library or application that provides a custom ‘_thread’ module
     must provide ‘_is_main_interpreter()’, just like the module’s other
     “private” attributes.  (gh-112826(8).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/

   (2) https://peps.python.org/pep-0709/

   (3) https://peps.python.org/pep-0667/

   (4) https://peps.python.org/pep-0667/

   (5) https://github.com/python/cpython/issues/121027

   (6) https://github.com/python/cpython/issues/115961

   (7) https://github.com/python/cpython/issues/65559

   (8) https://github.com/python/cpython/issues/112826


File: python.info,  Node: Changes in the C API,  Prev: Changes in the Python API,  Up: Porting to Python 3 13

1.1.12.2 Changes in the C API
.............................

   * ‘Python.h’ no longer includes the ‘<ieeefp.h>’ standard header.  It
     was included for the ‘finite()’ function which is now provided by
     the ‘<math.h>’ header.  It should now be included explicitly if
     needed.  Remove also the ‘HAVE_IEEEFP_H’ macro.  (Contributed by
     Victor Stinner in gh-108765(1).)

   * ‘Python.h’ no longer includes these standard header files:
     ‘<time.h>’, ‘<sys/select.h>’ and ‘<sys/time.h>’.  If needed, they
     should now be included explicitly.  For example, ‘<time.h>’
     provides the ‘clock()’ and ‘gmtime()’ functions, ‘<sys/select.h>’
     provides the ‘select()’ function, and ‘<sys/time.h>’ provides the
     ‘futimes()’, ‘gettimeofday()’ and ‘setitimer()’ functions.
     (Contributed by Victor Stinner in gh-108765(2).)

   * On Windows, ‘Python.h’ no longer includes the ‘<stddef.h>’ standard
     header file.  If needed, it should now be included explicitly.  For
     example, it provides ‘offsetof()’ function, and ‘size_t’ and
     ‘ptrdiff_t’ types.  Including ‘<stddef.h>’ explicitly was already
     needed by all other platforms, the ‘HAVE_STDDEF_H’ macro is only
     defined on Windows.  (Contributed by Victor Stinner in
     gh-108765(3).)

   * If the *note Py_LIMITED_API: 421. macro is defined,
     ‘Py_BUILD_CORE’, ‘Py_BUILD_CORE_BUILTIN’ and ‘Py_BUILD_CORE_MODULE’
     macros are now undefined by ‘<Python.h>’.  (Contributed by Victor
     Stinner in gh-85283(4).)

   * The old trashcan macros ‘Py_TRASHCAN_SAFE_BEGIN’ and
     ‘Py_TRASHCAN_SAFE_END’ were removed.  They should be replaced by
     the new macros ‘Py_TRASHCAN_BEGIN’ and ‘Py_TRASHCAN_END’.

     A ‘tp_dealloc’ function that has the old macros, such as:

          static void
          mytype_dealloc(mytype *p)
          {
              PyObject_GC_UnTrack(p);
              Py_TRASHCAN_SAFE_BEGIN(p);
              ...
              Py_TRASHCAN_SAFE_END
          }

     should migrate to the new macros as follows:

          static void
          mytype_dealloc(mytype *p)
          {
              PyObject_GC_UnTrack(p);
              Py_TRASHCAN_BEGIN(p, mytype_dealloc)
              ...
              Py_TRASHCAN_END
          }

     Note that ‘Py_TRASHCAN_BEGIN’ has a second argument which should be
     the deallocation function it is in.  The new macros were added in
     Python 3.8 and the old macros were deprecated in Python 3.11.
     (Contributed by Irit Katriel in gh-105111(5).)

   * *note PEP 667: 142. introduces several changes to frame-related
     functions:

        * The effects of mutating the dictionary returned from *note
          PyEval_GetLocals(): 356. in an *note optimized scope: 17e.
          have changed.  New dict entries added this way will now 'only'
          be visible to subsequent ‘PyEval_GetLocals()’ calls in that
          frame, as *note PyFrame_GetLocals(): 422, *note locals(): 141,
          and *note FrameType.f_locals: 182. no longer access the same
          underlying cached dictionary.  Changes made to entries for
          actual variable names and names added via the write-through
          proxy interfaces will be overwritten on subsequent calls to
          ‘PyEval_GetLocals()’ in that frame.  The recommended code
          update depends on how the function was being used, so refer to
          the deprecation notice on the function for details.

        * Calling *note PyFrame_GetLocals(): 422. in an *note optimized
          scope: 17e. now returns a write-through proxy rather than a
          snapshot that gets updated at ill-specified times.  If a
          snapshot is desired, it must be created explicitly (e.g.  with
          *note PyDict_Copy(): 423.), or by calling the new *note
          PyEval_GetFrameLocals(): 355. API.

        * ‘PyFrame_FastToLocals()’ and ‘PyFrame_FastToLocalsWithError()’
          no longer have any effect.  Calling these functions has been
          redundant since Python 3.11, when *note PyFrame_GetLocals():
          422. was first introduced.

        * ‘PyFrame_LocalsToFast()’ no longer has any effect.  Calling
          this function is redundant now that *note PyFrame_GetLocals():
          422. returns a write-through proxy for *note optimized scopes:
          17e.

   * Python 3.13 removed many private functions.  Some of them can be
     replaced using these alternatives:

        * ‘_PyDict_Pop()’: *note PyDict_Pop(): 342. or *note
          PyDict_PopString(): 343.;

        * ‘_PyDict_GetItemWithError()’: *note PyDict_GetItemRef(): 33b.;

        * ‘_PyErr_WriteUnraisableMsg()’: *note PyErr_FormatUnraisable():
          34f.;

        * ‘_PyEval_SetTrace()’: *note PyEval_SetTrace(): 424. or *note
          PyEval_SetTraceAllThreads(): 425.;

        * ‘_PyList_Extend()’: *note PyList_Extend(): 35e.;

        * ‘_PyLong_AsInt()’: *note PyLong_AsInt(): 362.;

        * ‘_PyMem_RawStrdup()’: ‘strdup()’;

        * ‘_PyMem_Strdup()’: ‘strdup()’;

        * ‘_PyObject_ClearManagedDict()’: *note
          PyObject_ClearManagedDict(): 36d.;

        * ‘_PyObject_VisitManagedDict()’: *note
          PyObject_VisitManagedDict(): 36c.;

        * ‘_PyThreadState_UncheckedGet()’: *note
          PyThreadState_GetUnchecked(): 374.;

        * ‘_PyTime_AsSecondsDouble()’: *note PyTime_AsSecondsDouble():
          331.;

        * ‘_PyTime_GetMonotonicClock()’: *note PyTime_Monotonic(): 332.
          or *note PyTime_MonotonicRaw(): 333.;

        * ‘_PyTime_GetPerfCounter()’: *note PyTime_PerfCounter(): 334.
          or *note PyTime_PerfCounterRaw(): 335.;

        * ‘_PyTime_GetSystemClock()’: *note PyTime_Time(): 336. or *note
          PyTime_TimeRaw(): 337.;

        * ‘_PyTime_MAX’: *note PyTime_MAX: 330.;

        * ‘_PyTime_MIN’: *note PyTime_MIN: 32f.;

        * ‘_PyTime_t’: *note PyTime_t: 32e.;

        * ‘_Py_HashPointer()’: *note Py_HashPointer(): 36b.;

        * ‘_Py_IsFinalizing()’: *note Py_IsFinalizing(): 35b.

     The pythoncapi-compat project(6) can be used to get most of these
     new functions on Python 3.12 and older.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/108765

   (2) https://github.com/python/cpython/issues/108765

   (3) https://github.com/python/cpython/issues/108765

   (4) https://github.com/python/cpython/issues/85283

   (5) https://github.com/python/cpython/issues/105111

   (6) https://github.com/python/pythoncapi-compat/


File: python.info,  Node: Regression Test Changes,  Next: Notable changes in 3 13 1,  Prev: Porting to Python 3 13,  Up: What’s New In Python 3 13

1.1.13 Regression Test Changes
------------------------------

   * Python built with ‘configure’ *note -with-pydebug: 427. now
     supports a *note -X presite=package.module: 176. command-line
     option.  If used, it specifies a module that should be imported
     early in the lifecycle of the interpreter, before ‘site.py’ is
     executed.  (Contributed by Łukasz Langa in gh-110769(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/110769


File: python.info,  Node: Notable changes in 3 13 1,  Next: Notable changes in 3 13 4,  Prev: Regression Test Changes,  Up: What’s New In Python 3 13

1.1.14 Notable changes in 3.13.1
--------------------------------

* Menu:

* sys: sys<2>.


File: python.info,  Node: sys<2>,  Up: Notable changes in 3 13 1

1.1.14.1 sys
............

   * The previously undocumented special function *note
     sys.getobjects(): 42a, which only exists in specialized builds of
     Python, may now return objects from other interpreters than the one
     it’s called in.


File: python.info,  Node: Notable changes in 3 13 4,  Prev: Notable changes in 3 13 1,  Up: What’s New In Python 3 13

1.1.15 Notable changes in 3.13.4
--------------------------------

* Menu:

* os.path: os path<2>.
* tarfile::


File: python.info,  Node: os path<2>,  Next: tarfile,  Up: Notable changes in 3 13 4

1.1.15.1 os.path
................

   * The 'strict' parameter to *note os.path.realpath(): 225. accepts a
     new value, *note os.path.ALLOW_MISSING: 42d.  If used, errors other
     than *note FileNotFoundError: 42e. will be re-raised; the resulting
     path can be missing but it will be free of symlinks.  (Contributed
     by Petr Viktorin for CVE 2025-4517(1).)

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2025-4517


File: python.info,  Node: tarfile,  Prev: os path<2>,  Up: Notable changes in 3 13 4

1.1.15.2 tarfile
................

   * *note data_filter(): 430. now normalizes symbolic link targets in
     order to avoid path traversal attacks.  (Contributed by Petr
     Viktorin in gh-127987(1) and CVE 2025-4138(2).)

   * *note extractall(): 431. now skips fixing up directory attributes
     when a directory was removed or replaced by another kind of file.
     (Contributed by Petr Viktorin in gh-127987(3) and CVE
     2024-12718(4).)

   * *note extract(): 432. and *note extractall(): 431. now (re-)apply
     the extraction filter when substituting a link (hard or symbolic)
     with a copy of another archive member, and when fixing up directory
     attributes.  The former raises a new exception, *note
     LinkFallbackError: 433.  (Contributed by Petr Viktorin for CVE
     2025-4330(5) and CVE 2024-12718(6).)

   * *note extract(): 432. and *note extractall(): 431. no longer
     extract rejected members when *note errorlevel(): 434. is zero.
     (Contributed by Matt Prodani and Petr Viktorin in gh-112887(7) and
     CVE 2025-4435(8).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127987

   (2) https://www.cve.org/CVERecord?id=CVE-2025-4138

   (3) https://github.com/python/cpython/issues/127987

   (4) https://www.cve.org/CVERecord?id=CVE-2024-12718

   (5) https://www.cve.org/CVERecord?id=CVE-2025-4330

   (6) https://www.cve.org/CVERecord?id=CVE-2024-12718

   (7) https://github.com/python/cpython/issues/112887

   (8) https://www.cve.org/CVERecord?id=CVE-2025-4435


File: python.info,  Node: What’s New In Python 3 12,  Next: What’s New In Python 3 11,  Prev: What’s New In Python 3 13,  Up: What’s New in Python

1.2 What’s New In Python 3.12
=============================


Editor: Adam Turner

This article explains the new features in Python 3.12, compared to 3.11.
Python 3.12 was released on October 2, 2023.  For full details, see the
*note changelog: 13c.

See also
........

PEP 693(1) – Python 3.12 Release Schedule

* Menu:

* Summary – Release highlights::
* New Features: New Features<3>.
* New Features Related to Type Hints::
* Other Language Changes: Other Language Changes<2>.
* New Modules: New Modules<2>.
* Improved Modules: Improved Modules<2>.
* Optimizations: Optimizations<2>.
* CPython bytecode changes::
* Demos and Tools::
* Deprecated::
* Removed::
* Porting to Python 3.12: Porting to Python 3 12.
* Build Changes: Build Changes<2>.
* C API Changes: C API Changes<2>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0693/


File: python.info,  Node: Summary – Release highlights,  Next: New Features<3>,  Up: What’s New In Python 3 12

1.2.1 Summary – Release highlights
----------------------------------

Python 3.12 is a stable release of the Python programming language, with
a mix of changes to the language and the standard library.  The library
changes focus on cleaning up deprecated APIs, usability, and
correctness.  Of note, the ‘distutils’ package has been removed from the
standard library.  Filesystem support in *note os: a1. and *note
pathlib: a4. has seen a number of improvements, and several modules have
better performance.

The language changes focus on usability, as *note f-strings: 439. have
had many limitations removed and ‘Did you mean …’ suggestions continue
to improve.  The new *note type parameter syntax: 43a. and *note type:
43b. statement improve ergonomics for using *note generic types: 43c.
and *note type aliases: 43d. with static type checkers.

This article doesn’t attempt to provide a complete specification of all
new features, but instead gives a convenient overview.  For full
details, you should refer to the documentation, such as the *note
Library Reference: 144. and *note Language Reference: 145.  If you want
to understand the complete implementation and design rationale for a
change, refer to the PEP for a particular new feature; but note that
PEPs usually are not kept up-to-date once a feature has been fully
implemented.

__________________________________________________________________

New syntax features:

   * *note PEP 695: 43a, type parameter syntax and the *note type: 43b.
     statement

New grammar features:

   * *note PEP 701: 43e, *note f-strings: 439. in the grammar

Interpreter improvements:

   * *note PEP 684: 43f, a unique per-interpreter *note GIL: 148.

   * *note PEP 669: 440, low impact monitoring

   * *note Improved 'Did you mean ...'  suggestions: 441.for *note
     NameError: 442, *note ImportError: 41c, and *note SyntaxError: 18d.
     exceptions

Python data model improvements:

   * *note PEP 688: 443, using the *note buffer protocol: 2e8. from
     Python

Significant improvements in the standard library:

   * The *note pathlib.Path: 229. class now supports subclassing

   * The *note os: a1. module received several improvements for Windows
     support

   * A *note command-line interface: 444. has been added to the *note
     sqlite3: cf. module

   * *note isinstance(): 445. checks against *note runtime-checkable
     protocols: 446. enjoy a speed up of between two and 20 times

   * The *note asyncio: a. package has had a number of performance
     improvements, with some benchmarks showing a 75% speed up.

   * A *note command-line interface: 447. has been added to the *note
     uuid: 110. module

   * Due to the changes in *note PEP 701: 43e, producing tokens via the
     *note tokenize: fb. module is up to 64% faster.

Security improvements:

   * Replace the builtin *note hashlib: 68. implementations of SHA1,
     SHA3, SHA2-384, SHA2-512, and MD5 with formally verified code from
     the HACL*(1) project.  These builtin implementations remain as
     fallbacks that are only used when OpenSSL does not provide them.

C API improvements:

   * *note PEP 697: 448, unstable C API tier

   * *note PEP 683: 449, immortal objects

CPython implementation improvements:

   * *note PEP 709: 44a, comprehension inlining

   * *note CPython support: 18f. for the Linux ‘perf’ profiler

   * Implement stack overflow protection on supported platforms

New typing features:

   * *note PEP 692: 44b, using *note TypedDict: 162. to annotate *note
     **kwargs: 44c.

   * *note PEP 698: 44d, *note typing.override(): 44e. decorator

Important deprecations, removals or restrictions:

   * PEP 623(2): Remove ‘wstr’ from Unicode objects in Python’s C API,
     reducing the size of every *note str: 44f. object by at least 8
     bytes.

   * PEP 632(3): Remove the ‘distutils’ package.  See the migration
     guide(4) for advice replacing the APIs it provided.  The
     third-party Setuptools(5) package continues to provide ‘distutils’,
     if you still require it in Python 3.12 and beyond.

   * gh-95299(6): Do not pre-install ‘setuptools’ in virtual
     environments created with *note venv: 111.  This means that
     ‘distutils’, ‘setuptools’, ‘pkg_resources’, and ‘easy_install’ will
     no longer available by default; to access these run ‘pip install
     setuptools’ in the *note activated: 450. virtual environment.

   * The ‘asynchat’, ‘asyncore’, and ‘imp’ modules have been removed,
     along with several *note unittest.TestCase: 451. *note method
     aliases: 452..

   ---------- Footnotes ----------

   (1) https://github.com/hacl-star/hacl-star/

   (2) https://peps.python.org/pep-0623/

   (3) https://peps.python.org/pep-0632/

   (4) https://peps.python.org/pep-0632/#migration-advice

   (5) 
https://setuptools.pypa.io/en/latest/deprecated/distutils-legacy.html

   (6) https://github.com/python/cpython/issues/95299


File: python.info,  Node: New Features<3>,  Next: New Features Related to Type Hints,  Prev: Summary – Release highlights,  Up: What’s New In Python 3 12

1.2.2 New Features
------------------

* Menu:

* PEP 695; Type Parameter Syntax: PEP 695 Type Parameter Syntax.
* PEP 701; Syntactic formalization of f-strings: PEP 701 Syntactic formalization of f-strings.
* PEP 684; A Per-Interpreter GIL: PEP 684 A Per-Interpreter GIL.
* PEP 669; Low impact monitoring for CPython: PEP 669 Low impact monitoring for CPython.
* PEP 688; Making the buffer protocol accessible in Python: PEP 688 Making the buffer protocol accessible in Python.
* PEP 709; Comprehension inlining: PEP 709 Comprehension inlining.
* Improved Error Messages::


File: python.info,  Node: PEP 695 Type Parameter Syntax,  Next: PEP 701 Syntactic formalization of f-strings,  Up: New Features<3>

1.2.2.1 PEP 695: Type Parameter Syntax
......................................

Generic classes and functions under PEP 484(1) were declared using a
verbose syntax that left the scope of type parameters unclear and
required explicit declarations of variance.

PEP 695(2) introduces a new, more compact and explicit way to create
*note generic classes: 455. and *note functions: 456.:

     def max[T](args: Iterable[T]) -> T:
         ...

     class list[T]:
         def __getitem__(self, index: int, /) -> T:
             ...

         def append(self, element: T) -> None:
             ...

In addition, the PEP introduces a new way to declare *note type aliases:
457. using the *note type: 43b. statement, which creates an instance of
*note TypeAliasType: 458.:

     type Point = tuple[float, float]

Type aliases can also be *note generic: 459.:

     type Point[T] = tuple[T, T]

The new syntax allows declaring *note TypeVarTuple: 15f. and *note
ParamSpec: 15e. parameters, as well as *note TypeVar: 15d. parameters
with bounds or constraints:

     type IntFunc[**P] = Callable[P, int]  # ParamSpec
     type LabeledTuple[*Ts] = tuple[str, *Ts]  # TypeVarTuple
     type HashableSequence[T: Hashable] = Sequence[T]  # TypeVar with bound
     type IntOrStrSequence[T: (int, str)] = Sequence[T]  # TypeVar with constraints

The value of type aliases and the bound and constraints of type
variables created through this syntax are evaluated only on demand (see
*note lazy evaluation: 45a.).  This means type aliases are able to refer
to other types defined later in the file.

Type parameters declared through a type parameter list are visible
within the scope of the declaration and any nested scopes, but not in
the outer scope.  For example, they can be used in the type annotations
for the methods of a generic class or in the class body.  However, they
cannot be used in the module scope after the class is defined.  See
*note Type parameter lists: 2b3. for a detailed description of the
runtime semantics of type parameters.

In order to support these scoping semantics, a new kind of scope is
introduced, the *note annotation scope: 188.  Annotation scopes behave
for the most part like function scopes, but interact differently with
enclosing class scopes.  In Python 3.13, *note annotations: 45b. will
also be evaluated in annotation scopes.

See PEP 695(3) for more details.

(PEP written by Eric Traut.  Implementation by Jelle Zijlstra, Eric
Traut, and others in gh-103764(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0695/

   (3) https://peps.python.org/pep-0695/

   (4) https://github.com/python/cpython/issues/103764


File: python.info,  Node: PEP 701 Syntactic formalization of f-strings,  Next: PEP 684 A Per-Interpreter GIL,  Prev: PEP 695 Type Parameter Syntax,  Up: New Features<3>

1.2.2.2 PEP 701: Syntactic formalization of f-strings
.....................................................

PEP 701(1) lifts some restrictions on the usage of *note f-strings: 439.
Expression components inside f-strings can now be any valid Python
expression, including strings reusing the same quote as the containing
f-string, multi-line expressions, comments, backslashes, and unicode
escape sequences.  Let’s cover these in detail:

   * Quote reuse: in Python 3.11, reusing the same quotes as the
     enclosing f-string raises a *note SyntaxError: 18d, forcing the
     user to either use other available quotes (like using double quotes
     or triple quotes if the f-string uses single quotes).  In Python
     3.12, you can now do things like this:

          >>> songs = ['Take me back to Eden', 'Alkaline', 'Ascensionism']
          >>> f"This is the playlist: {", ".join(songs)}"
          'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

     Note that before this change there was no explicit limit in how
     f-strings can be nested, but the fact that string quotes cannot be
     reused inside the expression component of f-strings made it
     impossible to nest f-strings arbitrarily.  In fact, this is the
     most nested f-string that could be written:

          >>> f"""{f'''{f'{f"{1+1}"}'}'''}"""
          '2'

     As now f-strings can contain any valid Python expression inside
     expression components, it is now possible to nest f-strings
     arbitrarily:

          >>> f"{f"{f"{f"{f"{f"{1+1}"}"}"}"}"}"
          '2'

   * Multi-line expressions and comments: In Python 3.11, f-string
     expressions must be defined in a single line, even if the
     expression within the f-string could normally span multiple lines
     (like literal lists being defined over multiple lines), making them
     harder to read.  In Python 3.12 you can now define f-strings
     spanning multiple lines, and add inline comments:

          >>> f"This is the playlist: {", ".join([
          ...     'Take me back to Eden',  # My, my, those eyes like fire
          ...     'Alkaline',              # Not acid nor alkaline
          ...     'Ascensionism'           # Take to the broken skies at last
          ... ])}"
          'This is the playlist: Take me back to Eden, Alkaline, Ascensionism'

   * Backslashes and unicode characters: before Python 3.12 f-string
     expressions couldn’t contain any ‘\’ character.  This also affected
     unicode *note escape sequences: 45d. (such as ‘\N{snowman}’) as
     these contain the ‘\N’ part that previously could not be part of
     expression components of f-strings.  Now, you can define
     expressions like this:

          >>> print(f"This is the playlist: {"\n".join(songs)}")
          This is the playlist: Take me back to Eden
          Alkaline
          Ascensionism
          >>> print(f"This is the playlist: {"\N{BLACK HEART SUIT}".join(songs)}")
          This is the playlist: Take me back to Eden♥Alkaline♥Ascensionism

See PEP 701(2) for more details.

As a positive side-effect of how this feature has been implemented (by
parsing f-strings with the PEG parser(3)), now error messages for
f-strings are more precise and include the exact location of the error.
For example, in Python 3.11, the following f-string raises a *note
SyntaxError: 18d.:

     >>> my_string = f"{x z y}" + f"{1 + 1}"
       File "<stdin>", line 1
         (x z y)
          ^^^
     SyntaxError: f-string: invalid syntax. Perhaps you forgot a comma?

but the error message doesn’t include the exact location of the error
within the line and also has the expression artificially surrounded by
parentheses.  In Python 3.12, as f-strings are parsed with the PEG
parser, error messages can be more precise and show the entire line:

     >>> my_string = f"{x z y}" + f"{1 + 1}"
       File "<stdin>", line 1
         my_string = f"{x z y}" + f"{1 + 1}"
                        ^^^
     SyntaxError: invalid syntax. Perhaps you forgot a comma?

(Contributed by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou,
Cristián Maureira-Fredes and Marta Gómez in gh-102856(4).  PEP written
by Pablo Galindo, Batuhan Taskaya, Lysandros Nikolaou and Marta Gómez).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0701/

   (2) https://peps.python.org/pep-0701/

   (3) https://peps.python.org/pep-0617/

   (4) https://github.com/python/cpython/issues/102856


File: python.info,  Node: PEP 684 A Per-Interpreter GIL,  Next: PEP 669 Low impact monitoring for CPython,  Prev: PEP 701 Syntactic formalization of f-strings,  Up: New Features<3>

1.2.2.3 PEP 684: A Per-Interpreter GIL
......................................

PEP 684(1) introduces a per-interpreter *note GIL: 148, so that
sub-interpreters may now be created with a unique GIL per interpreter.
This allows Python programs to take full advantage of multiple CPU
cores.  This is currently only available through the C-API, though a
Python API is anticipated for 3.13(2).

Use the new *note Py_NewInterpreterFromConfig(): 45f. function to create
an interpreter with its own GIL:

     PyInterpreterConfig config = {
         .check_multi_interp_extensions = 1,
         .gil = PyInterpreterConfig_OWN_GIL,
     };
     PyThreadState *tstate = NULL;
     PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
     if (PyStatus_Exception(status)) {
         return -1;
     }
     /* The new interpreter is now active in the current thread. */

For further examples how to use the C-API for sub-interpreters with a
per-interpreter GIL, see ‘Modules/_xxsubinterpretersmodule.c’.

(Contributed by Eric Snow in gh-104210(3), etc.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0684/

   (2) https://peps.python.org/pep-0554/

   (3) https://github.com/python/cpython/issues/104210


File: python.info,  Node: PEP 669 Low impact monitoring for CPython,  Next: PEP 688 Making the buffer protocol accessible in Python,  Prev: PEP 684 A Per-Interpreter GIL,  Up: New Features<3>

1.2.2.4 PEP 669: Low impact monitoring for CPython
..................................................

PEP 669(1) defines a new *note API: da. for profilers, debuggers, and
other tools to monitor events in CPython.  It covers a wide range of
events, including calls, returns, lines, exceptions, jumps, and more.
This means that you only pay for what you use, providing support for
near-zero overhead debuggers and coverage tools.  See ‘sys.monitoring’
for details.

(Contributed by Mark Shannon in gh-103082(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0669/

   (2) https://github.com/python/cpython/issues/103082


File: python.info,  Node: PEP 688 Making the buffer protocol accessible in Python,  Next: PEP 709 Comprehension inlining,  Prev: PEP 669 Low impact monitoring for CPython,  Up: New Features<3>

1.2.2.5 PEP 688: Making the buffer protocol accessible in Python
................................................................

PEP 688(1) introduces a way to use the *note buffer protocol: 2e8. from
Python code.  Classes that implement the *note __buffer__(): 462. method
are now usable as buffer types.

The new *note collections.abc.Buffer: 2e9. ABC provides a standard way
to represent buffer objects, for example in type annotations.  The new
*note inspect.BufferFlags: 463. enum represents the flags that can be
used to customize buffer creation.  (Contributed by Jelle Zijlstra in
gh-102500(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0688/

   (2) https://github.com/python/cpython/issues/102500


File: python.info,  Node: PEP 709 Comprehension inlining,  Next: Improved Error Messages,  Prev: PEP 688 Making the buffer protocol accessible in Python,  Up: New Features<3>

1.2.2.6 PEP 709: Comprehension inlining
.......................................

Dictionary, list, and set comprehensions are now inlined, rather than
creating a new single-use function object for each execution of the
comprehension.  This speeds up execution of a comprehension by up to two
times.  See PEP 709(1) for further details.

Comprehension iteration variables remain isolated and don’t overwrite a
variable of the same name in the outer scope, nor are they visible after
the comprehension.  Inlining does result in a few visible behavior
changes:

   * There is no longer a separate frame for the comprehension in
     tracebacks, and tracing/profiling no longer shows the comprehension
     as a function call.

   * The *note symtable: d8. module will no longer produce child symbol
     tables for each comprehension; instead, the comprehension’s locals
     will be included in the parent function’s symbol table.

   * Calling *note locals(): 141. inside a comprehension now includes
     variables from outside the comprehension, and no longer includes
     the synthetic ‘.0’ variable for the comprehension “argument”.

   * A comprehension iterating directly over ‘locals()’ (e.g.  ‘[k for k
     in locals()]’) may see “RuntimeError: dictionary changed size
     during iteration” when run under tracing (e.g.  code coverage
     measurement).  This is the same behavior already seen in e.g.  ‘for
     k in locals():’.  To avoid the error, first create a list of keys
     to iterate over: ‘keys = list(locals()); [k for k in keys]’.

(Contributed by Carl Meyer and Vladimir Matveev in PEP 709(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0709/

   (2) https://peps.python.org/pep-0709/


File: python.info,  Node: Improved Error Messages,  Prev: PEP 709 Comprehension inlining,  Up: New Features<3>

1.2.2.7 Improved Error Messages
...............................

   * Modules from the standard library are now potentially suggested as
     part of the error messages displayed by the interpreter when a
     *note NameError: 442. is raised to the top level.  (Contributed by
     Pablo Galindo in gh-98254(1).)

          >>> sys.version_info
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          NameError: name 'sys' is not defined. Did you forget to import 'sys'?

   * Improve the error suggestion for *note NameError: 442. exceptions
     for instances.  Now if a ‘NameError’ is raised in a method and the
     instance has an attribute that’s exactly equal to the name in the
     exception, the suggestion will include ‘self.<NAME>’ instead of the
     closest match in the method scope.  (Contributed by Pablo Galindo
     in gh-99139(2).)

          >>> class A:
          ...    def __init__(self):
          ...        self.blech = 1
          ...
          ...    def foo(self):
          ...        somethin = blech
          ...
          >>> A().foo()
          Traceback (most recent call last):
            File "<stdin>", line 1
              somethin = blech
                         ^^^^^
          NameError: name 'blech' is not defined. Did you mean: 'self.blech'?

   * Improve the *note SyntaxError: 18d. error message when the user
     types ‘import x from y’ instead of ‘from y import x’.  (Contributed
     by Pablo Galindo in gh-98931(3).)

          >>> import a.y.z from b.y.z
          Traceback (most recent call last):
            File "<stdin>", line 1
              import a.y.z from b.y.z
              ^^^^^^^^^^^^^^^^^^^^^^^
          SyntaxError: Did you mean to use 'from ... import ...' instead?

   * *note ImportError: 41c. exceptions raised from failed ‘from
     <module> import <name>’ statements now include suggestions for the
     value of ‘<name>’ based on the available names in ‘<module>’.
     (Contributed by Pablo Galindo in gh-91058(4).)

          >>> from collections import chainmap
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          ImportError: cannot import name 'chainmap' from 'collections'. Did you mean: 'ChainMap'?

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98254

   (2) https://github.com/python/cpython/issues/99139

   (3) https://github.com/python/cpython/issues/98931

   (4) https://github.com/python/cpython/issues/91058


File: python.info,  Node: New Features Related to Type Hints,  Next: Other Language Changes<2>,  Prev: New Features<3>,  Up: What’s New In Python 3 12

1.2.3 New Features Related to Type Hints
----------------------------------------

This section covers major changes affecting type hints(1) and the *note
typing: 104. module.

* Menu:

* PEP 692; Using TypedDict for more precise **kwargs typing: PEP 692 Using TypedDict for more precise **kwargs typing.
* PEP 698; Override Decorator for Static Typing: PEP 698 Override Decorator for Static Typing.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: PEP 692 Using TypedDict for more precise **kwargs typing,  Next: PEP 698 Override Decorator for Static Typing,  Up: New Features Related to Type Hints

1.2.3.1 PEP 692: Using ‘TypedDict’ for more precise ‘**kwargs’ typing
.....................................................................

Typing ‘**kwargs’ in a function signature as introduced by PEP 484(1)
allowed for valid annotations only in cases where all of the ‘**kwargs’
were of the same type.

PEP 692(2) specifies a more precise way of typing ‘**kwargs’ by relying
on typed dictionaries:

     from typing import TypedDict, Unpack

     class Movie(TypedDict):
       name: str
       year: int

     def foo(**kwargs: Unpack[Movie]): ...

See PEP 692(3) for more details.

(Contributed by Franek Magiera in gh-103629(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0692/

   (3) https://peps.python.org/pep-0692/

   (4) https://github.com/python/cpython/issues/103629


File: python.info,  Node: PEP 698 Override Decorator for Static Typing,  Prev: PEP 692 Using TypedDict for more precise **kwargs typing,  Up: New Features Related to Type Hints

1.2.3.2 PEP 698: Override Decorator for Static Typing
.....................................................

A new decorator *note typing.override(): 44e. has been added to the
*note typing: 104. module.  It indicates to type checkers that the
method is intended to override a method in a superclass.  This allows
type checkers to catch mistakes where a method that is intended to
override something in a base class does not in fact do so.

Example:

     from typing import override

     class Base:
       def get_color(self) -> str:
         return "blue"

     class GoodChild(Base):
       @override  # ok: overrides Base.get_color
       def get_color(self) -> str:
         return "yellow"

     class BadChild(Base):
       @override  # type checker error: does not override Base.get_color
       def get_colour(self) -> str:
         return "red"

See PEP 698(1) for more details.

(Contributed by Steven Troxler in gh-101561(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0698/

   (2) https://github.com/python/cpython/issues/101561


File: python.info,  Node: Other Language Changes<2>,  Next: New Modules<2>,  Prev: New Features Related to Type Hints,  Up: What’s New In Python 3 12

1.2.4 Other Language Changes
----------------------------

   * The parser now raises *note SyntaxError: 18d. when parsing source
     code containing null bytes.  (Contributed by Pablo Galindo in
     gh-96670(1).)

   * A backslash-character pair that is not a valid escape sequence now
     generates a *note SyntaxWarning: 469, instead of *note
     DeprecationWarning: 1a5.  For example, ‘re.compile("\d+\.\d+")’ now
     emits a ‘SyntaxWarning’ (‘"\d"’ is an invalid escape sequence, use
     raw strings for regular expression: ‘re.compile(r"\d+\.\d+")’).  In
     a future Python version, *note SyntaxError: 18d. will eventually be
     raised, instead of ‘SyntaxWarning’.  (Contributed by Victor Stinner
     in gh-98401(2).)

   * Octal escapes with value larger than ‘0o377’ (ex: ‘"\477"’),
     deprecated in Python 3.11, now produce a *note SyntaxWarning: 469,
     instead of *note DeprecationWarning: 1a5.  In a future Python
     version they will be eventually a *note SyntaxError: 18d.
     (Contributed by Victor Stinner in gh-98401(3).)

   * Variables used in the target part of comprehensions that are not
     stored to can now be used in assignment expressions (‘:=’).  For
     example, in ‘[(b := 1) for a, b.prop in some_iter]’, the assignment
     to ‘b’ is now allowed.  Note that assigning to variables stored to
     in the target part of comprehensions (like ‘a’) is still
     disallowed, as per PEP 572(4).  (Contributed by Nikita Sobolev in
     gh-100581(5).)

   * Exceptions raised in a class or type’s ‘__set_name__’ method are no
     longer wrapped by a *note RuntimeError: 195.  Context information
     is added to the exception as a PEP 678(6) note.  (Contributed by
     Irit Katriel in gh-77757(7).)

   * When a ‘try-except*’ construct handles the entire *note
     ExceptionGroup: 1b6. and raises one other exception, that exception
     is no longer wrapped in an ‘ExceptionGroup’.  Also changed in
     version 3.11.4.  (Contributed by Irit Katriel in gh-103590(8).)

   * The Garbage Collector now runs only on the eval breaker mechanism
     of the Python bytecode evaluation loop instead of object
     allocations.  The GC can also run when *note PyErr_CheckSignals():
     46a. is called so C extensions that need to run for a long time
     without executing any Python code also have a chance to execute the
     GC periodically.  (Contributed by Pablo Galindo in gh-97922(9).)

   * All builtin and extension callables expecting boolean parameters
     now accept arguments of any type instead of just *note bool: 46b.
     and *note int: 257.  (Contributed by Serhiy Storchaka in
     gh-60203(10).)

   * *note memoryview: 2eb. now supports the half-float type (the “e”
     format code).  (Contributed by Donghee Na and Antoine Pitrou in
     gh-90751(11).)

   * *note slice: 46c. objects are now hashable, allowing them to be
     used as dict keys and set items.  (Contributed by Will Bradshaw,
     Furkan Onder, and Raymond Hettinger in gh-101264(12).)

   * *note sum(): 46d. now uses Neumaier summation to improve accuracy
     and commutativity when summing floats or mixed ints and floats.
     (Contributed by Raymond Hettinger in gh-100425(13).)

   * *note ast.parse(): 1a8. now raises *note SyntaxError: 18d. instead
     of *note ValueError: 202. when parsing source code containing null
     bytes.  (Contributed by Pablo Galindo in gh-96670(14).)

   * The extraction methods in *note tarfile: de, and *note
     shutil.unpack_archive(): 46e, have a new a 'filter' argument that
     allows limiting tar features than may be surprising or dangerous,
     such as creating files outside the destination directory.  See
     *note tarfile extraction filters: 46f. for details.  In Python
     3.14, the default will switch to ‘'data'’.  (Contributed by Petr
     Viktorin in PEP 706(15).)

   * *note types.MappingProxyType: 470. instances are now hashable if
     the underlying mapping is hashable.  (Contributed by Serhiy
     Storchaka in gh-87995(16).)

   * Add *note support for the perf profiler: 18f. through the new
     environment variable *note PYTHONPERFSUPPORT: 471. and command-line
     option *note -X perf: 176, as well as the new *note
     sys.activate_stack_trampoline(): 472, *note
     sys.deactivate_stack_trampoline(): 473, and *note
     sys.is_stack_trampoline_active(): 474. functions.  (Design by Pablo
     Galindo.  Contributed by Pablo Galindo and Christian Heimes with
     contributions from Gregory P. Smith [Google] and Mark Shannon in
     gh-96123(17).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96670

   (2) https://github.com/python/cpython/issues/98401

   (3) https://github.com/python/cpython/issues/98401

   (4) https://peps.python.org/pep-0572/

   (5) https://github.com/python/cpython/issues/100581

   (6) https://peps.python.org/pep-0678/

   (7) https://github.com/python/cpython/issues/77757

   (8) https://github.com/python/cpython/issues/103590

   (9) https://github.com/python/cpython/issues/97922

   (10) https://github.com/python/cpython/issues/60203

   (11) https://github.com/python/cpython/issues/90751

   (12) https://github.com/python/cpython/issues/101264

   (13) https://github.com/python/cpython/issues/100425

   (14) https://github.com/python/cpython/issues/96670

   (15) https://peps.python.org/pep-0706/

   (16) https://github.com/python/cpython/issues/87995

   (17) https://github.com/python/cpython/issues/96123


File: python.info,  Node: New Modules<2>,  Next: Improved Modules<2>,  Prev: Other Language Changes<2>,  Up: What’s New In Python 3 12

1.2.5 New Modules
-----------------

   * None.


File: python.info,  Node: Improved Modules<2>,  Next: Optimizations<2>,  Prev: New Modules<2>,  Up: What’s New In Python 3 12

1.2.6 Improved Modules
----------------------

* Menu:

* array: array<2>.
* asyncio: asyncio<2>.
* calendar::
* csv::
* dis: dis<2>.
* fractions: fractions<2>.
* importlib.resources: importlib resources.
* inspect::
* itertools: itertools<2>.
* math: math<2>.
* os: os<2>.
* os.path: os path<3>.
* pathlib: pathlib<3>.
* platform::
* pdb: pdb<2>.
* random: random<2>.
* shutil: shutil<2>.
* sqlite3: sqlite3<2>.
* statistics: statistics<2>.
* sys: sys<3>.
* tempfile: tempfile<2>.
* threading::
* tkinter: tkinter<2>.
* tokenize::
* types: types<2>.
* typing: typing<3>.
* unicodedata: unicodedata<2>.
* unittest: unittest<2>.
* uuid::


File: python.info,  Node: array<2>,  Next: asyncio<2>,  Up: Improved Modules<2>

1.2.6.1 array
.............

   * The *note array.array: 1a0. class now supports subscripting, making
     it a *note generic type: 43c.  (Contributed by Jelle Zijlstra in
     gh-98658(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98658


File: python.info,  Node: asyncio<2>,  Next: calendar,  Prev: array<2>,  Up: Improved Modules<2>

1.2.6.2 asyncio
...............

   * The performance of writing to sockets in *note asyncio: a. has been
     significantly improved.  ‘asyncio’ now avoids unnecessary copying
     when writing to sockets and uses *note sendmsg(): 479. if the
     platform supports it.  (Contributed by Kumar Aditya in
     gh-91166(1).)

   * Add *note asyncio.eager_task_factory(): 47a. and *note
     asyncio.create_eager_task_factory(): 47b. functions to allow opting
     an event loop in to eager task execution, making some use-cases 2x
     to 5x faster.  (Contributed by Jacob Bower & Itamar Oren in
     gh-102853(2), gh-104140(3), and gh-104138(4))

   * On Linux, *note asyncio: a. uses *note asyncio.PidfdChildWatcher:
     47c. by default if *note os.pidfd_open(): 47d. is available and
     functional instead of *note asyncio.ThreadedChildWatcher: 47e.
     (Contributed by Kumar Aditya in gh-98024(5).)

   * The event loop now uses the best available child watcher for each
     platform (*note asyncio.PidfdChildWatcher: 47c. if supported and
     *note asyncio.ThreadedChildWatcher: 47e. otherwise), so manually
     configuring a child watcher is not recommended.  (Contributed by
     Kumar Aditya in gh-94597(6).)

   * Add 'loop_factory' parameter to *note asyncio.run(): 47f. to allow
     specifying a custom event loop factory.  (Contributed by Kumar
     Aditya in gh-99388(7).)

   * Add C implementation of *note asyncio.current_task(): 480. for
     4x-6x speedup.  (Contributed by Itamar Oren and Pranav Thulasiram
     Bhat in gh-100344(8).)

   * *note asyncio.iscoroutine(): 481. now returns ‘False’ for
     generators as *note asyncio: a. does not support legacy
     generator-based coroutines.  (Contributed by Kumar Aditya in
     gh-102748(9).)

   * *note asyncio.wait(): 482. and *note asyncio.as_completed(): 1aa.
     now accepts generators yielding tasks.  (Contributed by Kumar
     Aditya in gh-78530(10).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91166

   (2) https://github.com/python/cpython/issues/102853

   (3) https://github.com/python/cpython/issues/104140

   (4) https://github.com/python/cpython/issues/104138

   (5) https://github.com/python/cpython/issues/98024

   (6) https://github.com/python/cpython/issues/94597

   (7) https://github.com/python/cpython/issues/99388

   (8) https://github.com/python/cpython/issues/100344

   (9) https://github.com/python/cpython/issues/102748

   (10) https://github.com/python/cpython/issues/78530


File: python.info,  Node: calendar,  Next: csv,  Prev: asyncio<2>,  Up: Improved Modules<2>

1.2.6.3 calendar
................

   * Add enums *note calendar.Month: 484. and *note calendar.Day: 485.
     defining months of the year and days of the week.  (Contributed by
     Prince Roshan in gh-103636(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103636


File: python.info,  Node: csv,  Next: dis<2>,  Prev: calendar,  Up: Improved Modules<2>

1.2.6.4 csv
...........

   * Add *note csv.QUOTE_NOTNULL: 487. and *note csv.QUOTE_STRINGS: 488.
     flags to provide finer grained control of ‘None’ and empty strings
     by *note reader: 489. and *note writer: 48a. objects.


File: python.info,  Node: dis<2>,  Next: fractions<2>,  Prev: csv,  Up: Improved Modules<2>

1.2.6.5 dis
...........

   * Pseudo instruction opcodes (which are used by the compiler but do
     not appear in executable bytecode) are now exposed in the *note
     dis: 38. module.  *note HAVE_ARGUMENT: 48c. is still relevant to
     real opcodes, but it is not useful for pseudo instructions.  Use
     the new *note dis.hasarg: 29e. collection instead.  (Contributed by
     Irit Katriel in gh-94216(1).)

   * Add the *note dis.hasexc: 48d. collection to signify instructions
     that set an exception handler.  (Contributed by Irit Katriel in
     gh-94216(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94216

   (2) https://github.com/python/cpython/issues/94216


File: python.info,  Node: fractions<2>,  Next: importlib resources,  Prev: dis<2>,  Up: Improved Modules<2>

1.2.6.6 fractions
.................

   * Objects of type *note fractions.Fraction: 1e7. now support
     float-style formatting.  (Contributed by Mark Dickinson in
     gh-100161(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100161


File: python.info,  Node: importlib resources,  Next: inspect,  Prev: fractions<2>,  Up: Improved Modules<2>

1.2.6.7 importlib.resources
...........................

   * *note importlib.resources.as_file(): 490. now supports resource
     directories.  (Contributed by Jason R. Coombs in gh-97930(1).)

   * Rename first parameter of *note importlib.resources.files(): 491.
     to 'anchor'.  (Contributed by Jason R. Coombs in gh-100598(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97930

   (2) https://github.com/python/cpython/issues/100598


File: python.info,  Node: inspect,  Next: itertools<2>,  Prev: importlib resources,  Up: Improved Modules<2>

1.2.6.8 inspect
...............

   * Add *note inspect.markcoroutinefunction(): 493. to mark sync
     functions that return a *note coroutine: 494. for use with *note
     inspect.iscoroutinefunction(): 2e4.  (Contributed by Carlton Gibson
     in gh-99247(1).)

   * Add *note inspect.getasyncgenstate(): 495. and *note
     inspect.getasyncgenlocals(): 496. for determining the current state
     of asynchronous generators.  (Contributed by Thomas Krennwallner in
     gh-79940(2).)

   * The performance of *note inspect.getattr_static(): 497. has been
     considerably improved.  Most calls to the function should be at
     least 2x faster than they were in Python 3.11.  (Contributed by
     Alex Waygood in gh-103193(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99247

   (2) https://github.com/python/cpython/issues/79940

   (3) https://github.com/python/cpython/issues/103193


File: python.info,  Node: itertools<2>,  Next: math<2>,  Prev: inspect,  Up: Improved Modules<2>

1.2.6.9 itertools
.................

   * Add *note itertools.batched(): 201. for collecting into even-sized
     tuples where the last batch may be shorter than the rest.
     (Contributed by Raymond Hettinger in gh-98363(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98363


File: python.info,  Node: math<2>,  Next: os<2>,  Prev: itertools<2>,  Up: Improved Modules<2>

1.2.6.10 math
.............

   * Add *note math.sumprod(): 49a. for computing a sum of products.
     (Contributed by Raymond Hettinger in gh-100485(1).)

   * Extend *note math.nextafter(): 49b. to include a 'steps' argument
     for moving up or down multiple steps at a time.  (Contributed by
     Matthias Goergens, Mark Dickinson, and Raymond Hettinger in
     gh-94906(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100485

   (2) https://github.com/python/cpython/issues/94906


File: python.info,  Node: os<2>,  Next: os path<3>,  Prev: math<2>,  Up: Improved Modules<2>

1.2.6.11 os
...........

   * Add *note os.PIDFD_NONBLOCK: 49d. to open a file descriptor for a
     process with *note os.pidfd_open(): 47d. in non-blocking mode.
     (Contributed by Kumar Aditya in gh-93312(1).)

   * *note os.DirEntry: 49e. now includes an *note
     os.DirEntry.is_junction(): 49f. method to check if the entry is a
     junction.  (Contributed by Charles Machalow in gh-99547(2).)

   * Add *note os.listdrives(): 4a0, *note os.listvolumes(): 4a1. and
     *note os.listmounts(): 4a2. functions on Windows for enumerating
     drives, volumes and mount points.  (Contributed by Steve Dower in
     gh-102519(3).)

   * *note os.stat(): 4a3. and *note os.lstat(): 4a4. are now more
     accurate on Windows.  The ‘st_birthtime’ field will now be filled
     with the creation time of the file, and ‘st_ctime’ is deprecated
     but still contains the creation time (but in the future will return
     the last metadata change, for consistency with other platforms).
     ‘st_dev’ may be up to 64 bits and ‘st_ino’ up to 128 bits depending
     on your file system, and ‘st_rdev’ is always set to zero rather
     than incorrect values.  Both functions may be significantly faster
     on newer releases of Windows.  (Contributed by Steve Dower in
     gh-99726(4).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93312

   (2) https://github.com/python/cpython/issues/99547

   (3) https://github.com/python/cpython/issues/102519

   (4) https://github.com/python/cpython/issues/99726


File: python.info,  Node: os path<3>,  Next: pathlib<3>,  Prev: os<2>,  Up: Improved Modules<2>

1.2.6.12 os.path
................

   * Add *note os.path.isjunction(): 4a6. to check if a given path is a
     junction.  (Contributed by Charles Machalow in gh-99547(1).)

   * Add *note os.path.splitroot(): 4a7. to split a path into a triad
     ‘(drive, root, tail)’.  (Contributed by Barney Gale in
     gh-101000(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99547

   (2) https://github.com/python/cpython/issues/101000


File: python.info,  Node: pathlib<3>,  Next: platform,  Prev: os path<3>,  Up: Improved Modules<2>

1.2.6.13 pathlib
................

   * Add support for subclassing *note pathlib.PurePath: 4a9. and *note
     pathlib.Path: 229, plus their Posix- and Windows-specific variants.
     Subclasses may override the *note pathlib.PurePath.with_segments():
     4aa. method to pass information between path instances.

   * Add *note pathlib.Path.walk(): 4ab. for walking the directory trees
     and generating all file or directory names within them, similar to
     *note os.walk(): 4ac.  (Contributed by Stanislav Zmiev in
     gh-90385(1).)

   * Add 'walk_up' optional parameter to *note
     pathlib.PurePath.relative_to(): 2ca. to allow the insertion of ‘..’
     entries in the result; this behavior is more consistent with *note
     os.path.relpath(): 4ad.  (Contributed by Domenico Ragusa in
     gh-84538(2).)

   * Add *note pathlib.Path.is_junction(): 4ae. as a proxy to *note
     os.path.isjunction(): 4a6.  (Contributed by Charles Machalow in
     gh-99547(3).)

   * Add 'case_sensitive' optional parameter to *note
     pathlib.Path.glob(): 22d, *note pathlib.Path.rglob(): 22e. and
     *note pathlib.PurePath.match(): 4af. for matching the path’s case
     sensitivity, allowing for more precise control over the matching
     process.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/90385

   (2) https://github.com/python/cpython/issues/84538

   (3) https://github.com/python/cpython/issues/99547


File: python.info,  Node: platform,  Next: pdb<2>,  Prev: pathlib<3>,  Up: Improved Modules<2>

1.2.6.14 platform
.................

   * Add support for detecting Windows 11 and Windows Server releases
     past 2012.  Previously, lookups on Windows Server platforms newer
     than Windows Server 2012 and on Windows 11 would return
     ‘Windows-10’.  (Contributed by Steve Dower in gh-89545(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89545


File: python.info,  Node: pdb<2>,  Next: random<2>,  Prev: platform,  Up: Improved Modules<2>

1.2.6.15 pdb
............

   * Add convenience variables to hold values temporarily for debug
     session and provide quick access to values like the current frame
     or the return value.  (Contributed by Tian Gao in gh-103693(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103693


File: python.info,  Node: random<2>,  Next: shutil<2>,  Prev: pdb<2>,  Up: Improved Modules<2>

1.2.6.16 random
...............

   * Add *note random.binomialvariate(): 4b3.  (Contributed by Raymond
     Hettinger in gh-81620(1).)

   * Add a default of ‘lambd=1.0’ to *note random.expovariate(): 4b4.
     (Contributed by Raymond Hettinger in gh-100234(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/81620

   (2) https://github.com/python/cpython/issues/100234


File: python.info,  Node: shutil<2>,  Next: sqlite3<2>,  Prev: random<2>,  Up: Improved Modules<2>

1.2.6.17 shutil
...............

   * *note shutil.make_archive(): 4b6. now passes the 'root_dir'
     argument to custom archivers which support it.  In this case it no
     longer temporarily changes the current working directory of the
     process to 'root_dir' to perform archiving.  (Contributed by Serhiy
     Storchaka in gh-74696(1).)

   * *note shutil.rmtree(): 301. now accepts a new argument 'onexc'
     which is an error handler like 'onerror' but which expects an
     exception instance rather than a '(typ, val, tb)' triplet.
     'onerror' is deprecated.  (Contributed by Irit Katriel in
     gh-102828(2).)

   * *note shutil.which(): 4b7. now consults the 'PATHEXT' environment
     variable to find matches within 'PATH' on Windows even when the
     given 'cmd' includes a directory component.  (Contributed by
     Charles Machalow in gh-103179(3).)

     *note shutil.which(): 4b7. will call
     ‘NeedCurrentDirectoryForExePathW’ when querying for executables on
     Windows to determine if the current working directory should be
     prepended to the search path.  (Contributed by Charles Machalow in
     gh-103179(4).)

     *note shutil.which(): 4b7. will return a path matching the 'cmd'
     with a component from ‘PATHEXT’ prior to a direct match elsewhere
     in the search path on Windows.  (Contributed by Charles Machalow in
     gh-103179(5).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/74696

   (2) https://github.com/python/cpython/issues/102828

   (3) https://github.com/python/cpython/issues/103179

   (4) https://github.com/python/cpython/issues/103179

   (5) https://github.com/python/cpython/issues/103179


File: python.info,  Node: sqlite3<2>,  Next: statistics<2>,  Prev: shutil<2>,  Up: Improved Modules<2>

1.2.6.18 sqlite3
................

   * Add a *note command-line interface: 444.  (Contributed by Erlend E.
     Aasland in gh-77617(1).)

   * Add the *note sqlite3.Connection.autocommit: 4b9. attribute to
     *note sqlite3.Connection: 245. and the 'autocommit' parameter to
     *note sqlite3.connect(): 2a8. to control PEP 249(2)-compliant *note
     transaction handling: 4ba.  (Contributed by Erlend E. Aasland in
     gh-83638(3).)

   * Add 'entrypoint' keyword-only parameter to *note
     sqlite3.Connection.load_extension(): 4bb, for overriding the SQLite
     extension entry point.  (Contributed by Erlend E. Aasland in
     gh-103015(4).)

   * Add *note sqlite3.Connection.getconfig(): 4bc. and *note
     sqlite3.Connection.setconfig(): 4bd. to *note sqlite3.Connection:
     245. to make configuration changes to a database connection.
     (Contributed by Erlend E. Aasland in gh-103489(5).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/77617

   (2) https://peps.python.org/pep-0249/

   (3) https://github.com/python/cpython/issues/83638

   (4) https://github.com/python/cpython/issues/103015

   (5) https://github.com/python/cpython/issues/103489


File: python.info,  Node: statistics<2>,  Next: sys<3>,  Prev: sqlite3<2>,  Up: Improved Modules<2>

1.2.6.19 statistics
...................

   * Extend *note statistics.correlation(): 4bf. to include as a
     ‘ranked’ method for computing the Spearman correlation of ranked
     data.  (Contributed by Raymond Hettinger in gh-95861(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95861


File: python.info,  Node: sys<3>,  Next: tempfile<2>,  Prev: statistics<2>,  Up: Improved Modules<2>

1.2.6.20 sys
............

   * Add the *note sys.monitoring: da. namespace to expose the new *note
     PEP 669: 440. monitoring API. (Contributed by Mark Shannon in
     gh-103082(1).)

   * Add *note sys.activate_stack_trampoline(): 472. and *note
     sys.deactivate_stack_trampoline(): 473. for activating and
     deactivating stack profiler trampolines, and *note
     sys.is_stack_trampoline_active(): 474. for querying if stack
     profiler trampolines are active.  (Contributed by Pablo Galindo and
     Christian Heimes with contributions from Gregory P. Smith [Google]
     and Mark Shannon in gh-96123(2).)

   * Add *note sys.last_exc: 4c1. which holds the last unhandled
     exception that was raised (for post-mortem debugging use cases).
     Deprecate the three fields that have the same information in its
     legacy form: *note sys.last_type: 4c2, *note sys.last_value: 4c3.
     and *note sys.last_traceback: 4c4.  (Contributed by Irit Katriel in
     gh-102778(3).)

   * *note sys._current_exceptions(): 4c5. now returns a mapping from
     thread-id to an exception instance, rather than to a ‘(typ, exc,
     tb)’ tuple.  (Contributed by Irit Katriel in gh-103176(4).)

   * *note sys.setrecursionlimit(): 4c6. and *note
     sys.getrecursionlimit(): 4c7.  The recursion limit now applies only
     to Python code.  Builtin functions do not use the recursion limit,
     but are protected by a different mechanism that prevents recursion
     from causing a virtual machine crash.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103082

   (2) https://github.com/python/cpython/issues/96123

   (3) https://github.com/python/cpython/issues/102778

   (4) https://github.com/python/cpython/issues/103176


File: python.info,  Node: tempfile<2>,  Next: threading,  Prev: sys<3>,  Up: Improved Modules<2>

1.2.6.21 tempfile
.................

   * The *note tempfile.NamedTemporaryFile: 4c9. function has a new
     optional parameter 'delete_on_close' (Contributed by Evgeny Zorin
     in gh-58451(1).)

   * *note tempfile.mkdtemp(): 21f. now always returns an absolute path,
     even if the argument provided to the 'dir' parameter is a relative
     path.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/58451


File: python.info,  Node: threading,  Next: tkinter<2>,  Prev: tempfile<2>,  Up: Improved Modules<2>

1.2.6.22 threading
..................

   * Add *note threading.settrace_all_threads(): 4cb. and *note
     threading.setprofile_all_threads(): 4cc. that allow to set tracing
     and profiling functions in all running threads in addition to the
     calling one.  (Contributed by Pablo Galindo in gh-93503(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93503


File: python.info,  Node: tkinter<2>,  Next: tokenize,  Prev: threading,  Up: Improved Modules<2>

1.2.6.23 tkinter
................

   * ‘tkinter.Canvas.coords()’ now flattens its arguments.  It now
     accepts not only coordinates as separate arguments (‘x1, y1, x2,
     y2, ...’) and a sequence of coordinates (‘[x1, y1, x2, y2, ...]’),
     but also coordinates grouped in pairs (‘(x1, y1), (x2, y2), ...’
     and ‘[(x1, y1), (x2, y2), ...]’), like ‘create_*()’ methods.
     (Contributed by Serhiy Storchaka in gh-94473(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94473


File: python.info,  Node: tokenize,  Next: types<2>,  Prev: tkinter<2>,  Up: Improved Modules<2>

1.2.6.24 tokenize
.................

   * The *note tokenize: fb. module includes the changes introduced in
     PEP 701(1).  (Contributed by Marta Gómez Macías and Pablo Galindo
     in gh-102856(2).)  See *note Porting to Python 3.12: 4cf. for more
     information on the changes to the ‘tokenize’ module.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0701/

   (2) https://github.com/python/cpython/issues/102856


File: python.info,  Node: types<2>,  Next: typing<3>,  Prev: tokenize,  Up: Improved Modules<2>

1.2.6.25 types
..............

   * Add *note types.get_original_bases(): 4d1. to allow for further
     introspection of *note User-defined generic types: 4d2. when
     subclassed.  (Contributed by James Hilton-Balfe and Alex Waygood in
     gh-101827(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101827


File: python.info,  Node: typing<3>,  Next: unicodedata<2>,  Prev: types<2>,  Up: Improved Modules<2>

1.2.6.26 typing
...............

   * *note isinstance(): 445. checks against *note runtime-checkable
     protocols: 446. now use *note inspect.getattr_static(): 497. rather
     than *note hasattr(): 4d5. to lookup whether attributes exist.
     This means that descriptors and *note __getattr__(): 4d6. methods
     are no longer unexpectedly evaluated during ‘isinstance()’ checks
     against runtime-checkable protocols.  However, it may also mean
     that some objects which used to be considered instances of a
     runtime-checkable protocol may no longer be considered instances of
     that protocol on Python 3.12+, and vice versa.  Most users are
     unlikely to be affected by this change.  (Contributed by Alex
     Waygood in gh-102433(1).)

   * The members of a runtime-checkable protocol are now considered
     “frozen” at runtime as soon as the class has been created.
     Monkey-patching attributes onto a runtime-checkable protocol will
     still work, but will have no impact on *note isinstance(): 445.
     checks comparing objects to the protocol.  For example:

          >>> from typing import Protocol, runtime_checkable
          >>> @runtime_checkable
          ... class HasX(Protocol):
          ...     x = 1
          ...
          >>> class Foo: ...
          ...
          >>> f = Foo()
          >>> isinstance(f, HasX)
          False
          >>> f.x = 1
          >>> isinstance(f, HasX)
          True
          >>> HasX.y = 2
          >>> isinstance(f, HasX)  # unchanged, even though HasX now also has a "y" attribute
          True

     This change was made in order to speed up ‘isinstance()’ checks
     against runtime-checkable protocols.

   * The performance profile of *note isinstance(): 445. checks against
     *note runtime-checkable protocols: 446. has changed significantly.
     Most ‘isinstance()’ checks against protocols with only a few
     members should be at least 2x faster than in 3.11, and some may be
     20x faster or more.  However, ‘isinstance()’ checks against
     protocols with many members may be slower than in Python 3.11.
     (Contributed by Alex Waygood in gh-74690(2) and gh-103193(3).)

   * All *note typing.TypedDict: 162. and *note typing.NamedTuple: 2b0.
     classes now have the ‘__orig_bases__’ attribute.  (Contributed by
     Adrian Garcia Badaracco in gh-103699(4).)

   * Add ‘frozen_default’ parameter to *note
     typing.dataclass_transform(): 4d7.  (Contributed by Erik De Bonte
     in gh-99957(5).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102433

   (2) https://github.com/python/cpython/issues/74690

   (3) https://github.com/python/cpython/issues/103193

   (4) https://github.com/python/cpython/issues/103699

   (5) https://github.com/python/cpython/issues/99957


File: python.info,  Node: unicodedata<2>,  Next: unittest<2>,  Prev: typing<3>,  Up: Improved Modules<2>

1.2.6.27 unicodedata
....................

   * The Unicode database has been updated to version 15.0.0.
     (Contributed by Benjamin Peterson in gh-96734(1)).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96734


File: python.info,  Node: unittest<2>,  Next: uuid,  Prev: unicodedata<2>,  Up: Improved Modules<2>

1.2.6.28 unittest
.................

Add a ‘--durations’ command line option, showing the N slowest test
cases:

     python3 -m unittest --durations=3 lib.tests.test_threading
     .....
     Slowest test durations
     ----------------------------------------------------------------------
     1.210s     test_timeout (Lib.test.test_threading.BarrierTests)
     1.003s     test_default_timeout (Lib.test.test_threading.BarrierTests)
     0.518s     test_timeout (Lib.test.test_threading.EventTests)

     (0.000 durations hidden.  Use -v to show these durations.)
     ----------------------------------------------------------------------
     Ran 158 tests in 9.869s

     OK (skipped=3)

(Contributed by Giampaolo Rodola in gh-48330(1))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/48330


File: python.info,  Node: uuid,  Prev: unittest<2>,  Up: Improved Modules<2>

1.2.6.29 uuid
.............

   * Add a *note command-line interface: 447.  (Contributed by Adam
     Chhina in gh-88597(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88597


File: python.info,  Node: Optimizations<2>,  Next: CPython bytecode changes,  Prev: Improved Modules<2>,  Up: What’s New In Python 3 12

1.2.7 Optimizations
-------------------

   * Remove ‘wstr’ and ‘wstr_length’ members from Unicode objects.  It
     reduces object size by 8 or 16 bytes on 64bit platform.  ( PEP
     623(1)) (Contributed by Inada Naoki in gh-92536(2).)

   * Add experimental support for using the BOLT binary optimizer in the
     build process, which improves performance by 1-5%.  (Contributed by
     Kevin Modzelewski in gh-90536(3) and tuned by Donghee Na in
     gh-101525(4))

   * Speed up the regular expression substitution (functions *note
     re.sub(): 2a3. and *note re.subn(): 2a4. and corresponding
     ‘re.Pattern’ methods) for replacement strings containing group
     references by 2–3 times.  (Contributed by Serhiy Storchaka in
     gh-91524(5).)

   * Speed up *note asyncio.Task: 1be. creation by deferring expensive
     string formatting.  (Contributed by Itamar Oren in gh-103793(6).)

   * The *note tokenize.tokenize(): 4dc. and *note
     tokenize.generate_tokens(): 4dd. functions are up to 64% faster as
     a side effect of the changes required to cover PEP 701(7) in the
     *note tokenize: fb. module.  (Contributed by Marta Gómez Macías and
     Pablo Galindo in gh-102856(8).)

   * Speed up *note super(): 4de. method calls and attribute loads via
     the new *note LOAD_SUPER_ATTR: 4df. instruction.  (Contributed by
     Carl Meyer and Vladimir Matveev in gh-103497(9).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0623/

   (2) https://github.com/python/cpython/issues/92536

   (3) https://github.com/python/cpython/issues/90536

   (4) https://github.com/python/cpython/issues/101525

   (5) https://github.com/python/cpython/issues/91524

   (6) https://github.com/python/cpython/issues/103793

   (7) https://peps.python.org/pep-0701/

   (8) https://github.com/python/cpython/issues/102856

   (9) https://github.com/python/cpython/issues/103497


File: python.info,  Node: CPython bytecode changes,  Next: Demos and Tools,  Prev: Optimizations<2>,  Up: What’s New In Python 3 12

1.2.8 CPython bytecode changes
------------------------------

   * Remove the ‘LOAD_METHOD’ instruction.  It has been merged into
     *note LOAD_ATTR: 4e1.  ‘LOAD_ATTR’ will now behave like the old
     ‘LOAD_METHOD’ instruction if the low bit of its oparg is set.
     (Contributed by Ken Jin in gh-93429(1).)

   * Remove the ‘JUMP_IF_FALSE_OR_POP’ and ‘JUMP_IF_TRUE_OR_POP’
     instructions.  (Contributed by Irit Katriel in gh-102859(2).)

   * Remove the ‘PRECALL’ instruction.  (Contributed by Mark Shannon in
     gh-92925(3).)

   * Add the *note BINARY_SLICE: 4e2. and *note STORE_SLICE: 4e3.
     instructions.  (Contributed by Mark Shannon in gh-94163(4).)

   * Add the *note CALL_INTRINSIC_1: 4e4. instructions.  (Contributed by
     Mark Shannon in gh-99005(5).)

   * Add the *note CALL_INTRINSIC_2: 4e5. instruction.  (Contributed by
     Irit Katriel in gh-101799(6).)

   * Add the *note CLEANUP_THROW: 4e6. instruction.  (Contributed by
     Brandt Bucher in gh-90997(7).)

   * Add the ‘END_SEND’ instruction.  (Contributed by Mark Shannon in
     gh-103082(8).)

   * Add the *note LOAD_FAST_AND_CLEAR: 4e7. instruction as part of the
     implementation of PEP 709(9).  (Contributed by Carl Meyer in
     gh-101441(10).)

   * Add the *note LOAD_FAST_CHECK: 4e8. instruction.  (Contributed by
     Dennis Sweeney in gh-93143(11).)

   * Add the *note LOAD_FROM_DICT_OR_DEREF: 4e9, *note
     LOAD_FROM_DICT_OR_GLOBALS: 4ea, and *note LOAD_LOCALS: 4eb. opcodes
     as part of the implementation of PEP 695(12).  Remove the
     ‘LOAD_CLASSDEREF’ opcode, which can be replaced with ‘LOAD_LOCALS’
     plus ‘LOAD_FROM_DICT_OR_DEREF’.  (Contributed by Jelle Zijlstra in
     gh-103764(13).)

   * Add the *note LOAD_SUPER_ATTR: 4df. instruction.  (Contributed by
     Carl Meyer and Vladimir Matveev in gh-103497(14).)

   * Add the *note RETURN_CONST: 4ec. instruction.  (Contributed by
     Wenyang Wang in gh-101632(15).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93429

   (2) https://github.com/python/cpython/issues/102859

   (3) https://github.com/python/cpython/issues/92925

   (4) https://github.com/python/cpython/issues/94163

   (5) https://github.com/python/cpython/issues/99005

   (6) https://github.com/python/cpython/issues/101799

   (7) https://github.com/python/cpython/issues/90997

   (8) https://github.com/python/cpython/issues/103082

   (9) https://peps.python.org/pep-0709/

   (10) https://github.com/python/cpython/issues/101441

   (11) https://github.com/python/cpython/issues/93143

   (12) https://peps.python.org/pep-0695/

   (13) https://github.com/python/cpython/issues/103764

   (14) https://github.com/python/cpython/issues/103497

   (15) https://github.com/python/cpython/issues/101632


File: python.info,  Node: Demos and Tools,  Next: Deprecated,  Prev: CPython bytecode changes,  Up: What’s New In Python 3 12

1.2.9 Demos and Tools
---------------------

   * Remove the ‘Tools/demo/’ directory which contained old demo
     scripts.  A copy can be found in the old-demos project(1).
     (Contributed by Victor Stinner in gh-97681(2).)

   * Remove outdated example scripts of the ‘Tools/scripts/’ directory.
     A copy can be found in the old-demos project(3).  (Contributed by
     Victor Stinner in gh-97669(4).)

   ---------- Footnotes ----------

   (1) https://github.com/gvanrossum/old-demos

   (2) https://github.com/python/cpython/issues/97681

   (3) https://github.com/gvanrossum/old-demos

   (4) https://github.com/python/cpython/issues/97669


File: python.info,  Node: Deprecated,  Next: Removed,  Prev: Demos and Tools,  Up: What’s New In Python 3 12

1.2.10 Deprecated
-----------------

   * *note argparse: 6.: The 'type', 'choices', and 'metavar' parameters
     of ‘argparse.BooleanOptionalAction’ are deprecated and will be
     removed in 3.14.  (Contributed by Nikita Sobolev in gh-92248(1).)

   * *note ast: 8.: The following ‘ast’ features have been deprecated in
     documentation since Python 3.8, now cause a *note
     DeprecationWarning: 1a5. to be emitted at runtime when they are
     accessed or used, and will be removed in Python 3.14:

        * ‘ast.Num’

        * ‘ast.Str’

        * ‘ast.Bytes’

        * ‘ast.NameConstant’

        * ‘ast.Ellipsis’

     Use *note ast.Constant: 2b9. instead.  (Contributed by Serhiy
     Storchaka in gh-90953(2).)

   * *note asyncio: a.:

        * The child watcher classes *note asyncio.MultiLoopChildWatcher:
          2ba, *note asyncio.FastChildWatcher: 2bb, *note
          asyncio.AbstractChildWatcher: 2bc. and *note
          asyncio.SafeChildWatcher: 2bd. are deprecated and will be
          removed in Python 3.14.  (Contributed by Kumar Aditya in
          gh-94597(3).)

        * *note asyncio.set_child_watcher(): 2be, *note
          asyncio.get_child_watcher(): 2bf, *note
          asyncio.AbstractEventLoopPolicy.set_child_watcher(): 2c0. and
          *note asyncio.AbstractEventLoopPolicy.get_child_watcher():
          2c1. are deprecated and will be removed in Python 3.14.
          (Contributed by Kumar Aditya in gh-94597(4).)

        * The *note get_event_loop(): 2c2. method of the default event
          loop policy now emits a *note DeprecationWarning: 1a5. if
          there is no current event loop set and it decides to create
          one.  (Contributed by Serhiy Storchaka and Guido van Rossum in
          gh-100160(5).)

   * *note calendar: 14.: ‘calendar.January’ and ‘calendar.February’
     constants are deprecated and replaced by *note calendar.JANUARY:
     2f9. and *note calendar.FEBRUARY: 2fa.  (Contributed by Prince
     Roshan in gh-103636(6).)

   * *note collections.abc: 1e.: Deprecated *note
     collections.abc.ByteString: 2e7.

     Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
     implements the *note buffer protocol: 2e8. at runtime.  For use in
     type annotations, either use *note Buffer: 2e9. or a union that
     explicitly specifies the types your code supports (e.g., ‘bytes |
     bytearray | memoryview’).

     ‘ByteString’ was originally intended to be an abstract class that
     would serve as a supertype of both *note bytes: 1c2. and *note
     bytearray: 2ea.  However, since the ABC never had any methods,
     knowing that an object was an instance of ‘ByteString’ never
     actually told you anything useful about the object.  Other common
     buffer types such as *note memoryview: 2eb. were also never
     understood as subtypes of ‘ByteString’ (either at runtime or by
     static type checkers).

     See PEP 688(7) for more details.  (Contributed by Shantanu Jain in
     gh-91896(8).)

   * *note datetime: 30.: *note datetime.datetime: 1cc.’s *note
     utcnow(): 2fc. and *note utcfromtimestamp(): 2fd. are deprecated
     and will be removed in a future version.  Instead, use
     timezone-aware objects to represent datetimes in UTC: respectively,
     call *note now(): 4ef. and *note fromtimestamp(): 4f0. with the
     'tz' parameter set to *note datetime.UTC: 4f1.  (Contributed by
     Paul Ganssle in gh-103857(9).)

   * *note email: 3b.: Deprecate the 'isdst' parameter in *note
     email.utils.localtime(): 2c4.  (Contributed by Alan Williams in
     gh-72346(10).)

   * *note importlib.abc: 78.: Deprecated the following classes,
     scheduled for removal in Python 3.14:

        * ‘importlib.abc.ResourceReader’

        * ‘importlib.abc.Traversable’

        * ‘importlib.abc.TraversableResources’

     Use *note importlib.resources.abc: 7c. classes instead:

        * *note importlib.resources.abc.Traversable: 1f3.

        * *note importlib.resources.abc.TraversableResources: 2c5.

     (Contributed by Jason R. Coombs and Hugo van Kemenade in
     gh-93963(11).)

   * *note itertools: 81.: Deprecate the support for copy, deepcopy, and
     pickle operations, which is undocumented, inefficient, historically
     buggy, and inconsistent.  This will be removed in 3.14 for a
     significant reduction in code volume and maintenance burden.
     (Contributed by Raymond Hettinger in gh-101588(12).)

   * *note multiprocessing: 94.: In Python 3.14, the default
     ‘multiprocessing’ start method will change to a safer one on Linux,
     BSDs, and other non-macOS POSIX platforms where ‘'fork'’ is
     currently the default (gh-84559(13)).  Adding a runtime warning
     about this was deemed too disruptive as the majority of code is not
     expected to care.  Use the *note get_context(): 2c6. or *note
     set_start_method(): 2c7. APIs to explicitly specify when your code
     'requires' ‘'fork'’.  See *note contexts and start methods: 2c8.

   * *note pkgutil: a9.: *note pkgutil.find_loader(): 2cb. and *note
     pkgutil.get_loader(): 2cc. are deprecated and will be removed in
     Python 3.14; use *note importlib.util.find_spec(): 2cd. instead.
     (Contributed by Nikita Sobolev in gh-97850(14).)

   * *note pty: b1.: The module has two undocumented ‘master_open()’ and
     ‘slave_open()’ functions that have been deprecated since Python 2
     but only gained a proper *note DeprecationWarning: 1a5. in 3.12.
     Remove them in 3.14.  (Contributed by Soumendra Ganguly and Gregory
     P. Smith in gh-85984(15).)

   * *note os: a1.:

        * The ‘st_ctime’ fields return by *note os.stat(): 4a3. and
          *note os.lstat(): 4a4. on Windows are deprecated.  In a future
          release, they will contain the last metadata change time,
          consistent with other platforms.  For now, they still contain
          the creation time, which is also available in the new
          ‘st_birthtime’ field.  (Contributed by Steve Dower in
          gh-99726(16).)

        * On POSIX platforms, *note os.fork(): 197. can now raise a
          *note DeprecationWarning: 1a5. when it can detect being called
          from a multithreaded process.  There has always been a
          fundamental incompatibility with the POSIX platform when doing
          so.  Even if such code 'appeared' to work.  We added the
          warning to raise awareness as issues encountered by code doing
          this are becoming more frequent.  See the ‘os.fork()’
          documentation for more details along with this discussion on
          fork being incompatible with threads(17) for 'why' we’re now
          surfacing this longstanding platform compatibility problem to
          developers.

     When this warning appears due to usage of *note multiprocessing:
     94. or *note concurrent.futures: 21. the fix is to use a different
     ‘multiprocessing’ start method such as ‘"spawn"’ or ‘"forkserver"’.

   * *note shutil: c5.: The 'onerror' argument of *note shutil.rmtree():
     301. is deprecated; use 'onexc' instead.  (Contributed by Irit
     Katriel in gh-102828(18).)

   * *note sqlite3: cf.:

        * *note default adapters and converters: 4f2. are now
          deprecated.  Instead, use the *note Adapter and converter
          recipes: 4f3. and tailor them to your needs.  (Contributed by
          Erlend E. Aasland in gh-90016(19).)

        * In *note execute(): 2d1, *note DeprecationWarning: 1a5. is now
          emitted when *note named placeholders: 2d3. are used together
          with parameters supplied as a *note sequence: 4f4. instead of
          as a *note dict: 256.  Starting from Python 3.14, using named
          placeholders with parameters supplied as a sequence will raise
          a *note ProgrammingError: 4f5.  (Contributed by Erlend E.
          Aasland in gh-101698(20).)

   * *note sys: d9.: The *note sys.last_type: 4c2, *note sys.last_value:
     4c3. and *note sys.last_traceback: 4c4. fields are deprecated.  Use
     *note sys.last_exc: 4c1. instead.  (Contributed by Irit Katriel in
     gh-102778(21).)

   * *note tarfile: de.: Extracting tar archives without specifying
     'filter' is deprecated until Python 3.14, when ‘'data'’ filter will
     become the default.  See *note Extraction filters: 46f. for
     details.

   * *note typing: 104.:

        * *note typing.Hashable: 4f6. and *note typing.Sized: 4f7,
          aliases for *note collections.abc.Hashable: 4f8. and *note
          collections.abc.Sized: 4f9. respectively, are deprecated.
          (gh-94309(22).)

        * *note typing.ByteString: 2ee, deprecated since Python 3.9, now
          causes a *note DeprecationWarning: 1a5. to be emitted when it
          is used.  (Contributed by Alex Waygood in gh-91896(23).)

   * *note xml.etree.ElementTree: 125.: The module now emits *note
     DeprecationWarning: 1a5. when testing the truth value of an *note
     xml.etree.ElementTree.Element: 310.  Before, the Python
     implementation emitted *note FutureWarning: 418, and the C
     implementation emitted nothing.  (Contributed by Jacob Walls in
     gh-83122(24).)

   * The 3-arg signatures (type, value, traceback) of *note coroutine
     throw(): 4fa, *note generator throw(): 4fb. and *note async
     generator throw(): 4fc. are deprecated and may be removed in a
     future version of Python.  Use the single-arg versions of these
     functions instead.  (Contributed by Ofey Chan in gh-89874(25).)

   * *note DeprecationWarning: 1a5. is now raised when *note
     __package__: 2d7. on a module differs from *note __spec__.parent:
     2d8. (previously it was *note ImportWarning: 4fd.).  (Contributed
     by Brett Cannon in gh-65961(26).)

   * Setting *note __package__: 2d7. or *note __cached__: 2d5. on a
     module is deprecated, and will cease to be set or taken into
     consideration by the import system in Python 3.14.  (Contributed by
     Brett Cannon in gh-65961(27).)

   * The bitwise inversion operator (‘~’) on bool is deprecated.  It
     will throw an error in Python 3.16.  Use ‘not’ for logical negation
     of bools instead.  In the rare case that you really need the
     bitwise inversion of the underlying ‘int’, convert to int
     explicitly: ‘~int(x)’.  (Contributed by Tim Hoffmann in
     gh-103487(28).)

   * Accessing *note co_lnotab: 2e0. on code objects was deprecated in
     Python 3.10 via PEP 626(29), but it only got a proper *note
     DeprecationWarning: 1a5. in 3.12.  May be removed in 3.15.
     (Contributed by Nikita Sobolev in gh-101866(30).)

* Menu:

* Pending Removal in Python 3.13: Pending Removal in Python 3 13.
* Pending Removal in Python 3.14: Pending Removal in Python 3 14<3>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<3>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<3>.
* Pending removal in Python 3.17: Pending removal in Python 3 17<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92248

   (2) https://github.com/python/cpython/issues/90953

   (3) https://github.com/python/cpython/issues/94597

   (4) https://github.com/python/cpython/issues/94597

   (5) https://github.com/python/cpython/issues/100160

   (6) https://github.com/python/cpython/issues/103636

   (7) https://peps.python.org/pep-0688/#current-options

   (8) https://github.com/python/cpython/issues/91896

   (9) https://github.com/python/cpython/issues/103857

   (10) https://github.com/python/cpython/issues/72346

   (11) https://github.com/python/cpython/issues/93963

   (12) https://github.com/python/cpython/issues/101588

   (13) https://github.com/python/cpython/issues/84559

   (14) https://github.com/python/cpython/issues/97850

   (15) https://github.com/python/cpython/issues/85984

   (16) https://github.com/python/cpython/issues/99726

   (17) 
https://discuss.python.org/t/concerns-regarding-deprecation-of-fork-with-alive-threads/33555

   (18) https://github.com/python/cpython/issues/102828

   (19) https://github.com/python/cpython/issues/90016

   (20) https://github.com/python/cpython/issues/101698

   (21) https://github.com/python/cpython/issues/102778

   (22) https://github.com/python/cpython/issues/94309

   (23) https://github.com/python/cpython/issues/91896

   (24) https://github.com/python/cpython/issues/83122

   (25) https://github.com/python/cpython/issues/89874

   (26) https://github.com/python/cpython/issues/65961

   (27) https://github.com/python/cpython/issues/65961

   (28) https://github.com/python/cpython/issues/103487

   (29) https://peps.python.org/pep-0626/

   (30) https://github.com/python/cpython/issues/101866


File: python.info,  Node: Pending Removal in Python 3 13,  Next: Pending Removal in Python 3 14<3>,  Up: Deprecated

1.2.10.1 Pending Removal in Python 3.13
.......................................

Modules (see PEP 594(1)):

   * ‘aifc’

   * ‘audioop’

   * ‘cgi’

   * ‘cgitb’

   * ‘chunk’

   * ‘crypt’

   * ‘imghdr’

   * ‘mailcap’

   * ‘msilib’

   * ‘nis’

   * ‘nntplib’

   * ‘ossaudiodev’

   * ‘pipes’

   * ‘sndhdr’

   * ‘spwd’

   * ‘sunau’

   * ‘telnetlib’

   * ‘uu’

   * ‘xdrlib’

Other modules:

   * ‘lib2to3’, and the ‘2to3’ program (gh-84540(2))

APIs:

   * ‘configparser.LegacyInterpolation’ (gh-90765(3))

   * ‘locale.resetlocale()’ (gh-90817(4))

   * ‘turtle.RawTurtle.settiltangle()’ (gh-50096(5))

   * ‘unittest.findTestCases()’ (gh-50096(6))

   * ‘unittest.getTestCaseNames()’ (gh-50096(7))

   * ‘unittest.makeSuite()’ (gh-50096(8))

   * ‘unittest.TestProgram.usageExit()’ (gh-67048(9))

   * ‘webbrowser.MacOSX’ (gh-86421(10))

   * *note classmethod: 166. descriptor chaining (gh-89519(11))

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://github.com/python/cpython/issues/84540

   (3) https://github.com/python/cpython/issues/90765

   (4) https://github.com/python/cpython/issues/90817

   (5) https://github.com/python/cpython/issues/50096

   (6) https://github.com/python/cpython/issues/50096

   (7) https://github.com/python/cpython/issues/50096

   (8) https://github.com/python/cpython/issues/50096

   (9) https://github.com/python/cpython/issues/67048

   (10) https://github.com/python/cpython/issues/86421

   (11) https://github.com/python/cpython/issues/89519


File: python.info,  Node: Pending Removal in Python 3 14<3>,  Next: Pending Removal in Python 3 15<3>,  Prev: Pending Removal in Python 3 13,  Up: Deprecated

1.2.10.2 Pending Removal in Python 3.14
.......................................

   * *note argparse: 6.: The 'type', 'choices', and 'metavar' parameters
     of ‘argparse.BooleanOptionalAction’ are deprecated and will be
     removed in 3.14.  (Contributed by Nikita Sobolev in gh-92248(1).)

   * *note ast: 8.: The following features have been deprecated in
     documentation since Python 3.8, now cause a *note
     DeprecationWarning: 1a5. to be emitted at runtime when they are
     accessed or used, and will be removed in Python 3.14:

        * ‘ast.Num’

        * ‘ast.Str’

        * ‘ast.Bytes’

        * ‘ast.NameConstant’

        * ‘ast.Ellipsis’

     Use *note ast.Constant: 2b9. instead.  (Contributed by Serhiy
     Storchaka in gh-90953(2).)

   * *note asyncio: a.:

        * The child watcher classes *note MultiLoopChildWatcher: 2ba,
          *note FastChildWatcher: 2bb, *note AbstractChildWatcher: 2bc.
          and *note SafeChildWatcher: 2bd. are deprecated and will be
          removed in Python 3.14.  (Contributed by Kumar Aditya in
          gh-94597(3).)

        * *note asyncio.set_child_watcher(): 2be, *note
          asyncio.get_child_watcher(): 2bf, *note
          asyncio.AbstractEventLoopPolicy.set_child_watcher(): 2c0. and
          *note asyncio.AbstractEventLoopPolicy.get_child_watcher():
          2c1. are deprecated and will be removed in Python 3.14.
          (Contributed by Kumar Aditya in gh-94597(4).)

        * The *note get_event_loop(): 2c2. method of the default event
          loop policy now emits a *note DeprecationWarning: 1a5. if
          there is no current event loop set and it decides to create
          one.  (Contributed by Serhiy Storchaka and Guido van Rossum in
          gh-100160(5).)

   * *note builtins: 12.: ‘bool(NotImplemented)’ now emits a *note
     DeprecationWarning: 1a5. and will raise a *note TypeError: 2c3. in
     Python 3.14.  (Contributed by Jelle Zijlstra in gh-118767(6).)

   * *note email: 3b.: Deprecated the 'isdst' parameter in *note
     email.utils.localtime(): 2c4.  (Contributed by Alan Williams in
     gh-72346(7).)

   * *note importlib.abc: 78. deprecated classes:

        * ‘importlib.abc.ResourceReader’

        * ‘importlib.abc.Traversable’

        * ‘importlib.abc.TraversableResources’

     Use *note importlib.resources.abc: 7c. classes instead:

        * *note importlib.resources.abc.Traversable: 1f3.

        * *note importlib.resources.abc.TraversableResources: 2c5.

     (Contributed by Jason R. Coombs and Hugo van Kemenade in
     gh-93963(8).)

   * *note itertools: 81. had undocumented, inefficient, historically
     buggy, and inconsistent support for copy, deepcopy, and pickle
     operations.  This will be removed in 3.14 for a significant
     reduction in code volume and maintenance burden.  (Contributed by
     Raymond Hettinger in gh-101588(9).)

   * *note multiprocessing: 94.: The default start method will change to
     a safer one on Linux, BSDs, and other non-macOS POSIX platforms
     where ‘'fork'’ is currently the default (gh-84559(10)).  Adding a
     runtime warning about this was deemed too disruptive as the
     majority of code is not expected to care.  Use the *note
     get_context(): 2c6. or *note set_start_method(): 2c7. APIs to
     explicitly specify when your code 'requires' ‘'fork'’.  See *note
     Contexts and start methods: 2c8.

   * *note pathlib: a4.: *note is_relative_to(): 2c9. and *note
     relative_to(): 2ca.: passing additional arguments is deprecated.

   * *note pkgutil: a9.: *note find_loader(): 2cb. and *note
     get_loader(): 2cc. now raise *note DeprecationWarning: 1a5.; use
     *note importlib.util.find_spec(): 2cd. instead.  (Contributed by
     Nikita Sobolev in gh-97850(11).)

   * *note pty: b1.:

        * ‘master_open()’: use *note pty.openpty(): 2ce.

        * ‘slave_open()’: use *note pty.openpty(): 2ce.

   * *note sqlite3: cf.:

        * *note version: 2cf. and *note version_info: 2d0.

        * *note execute(): 2d1. and *note executemany(): 2d2. if *note
          named placeholders: 2d3. are used and 'parameters' is a
          sequence instead of a *note dict: 256.

   * *note urllib: 108.: ‘urllib.parse.Quoter’ is deprecated: it was not
     intended to be a public API. (Contributed by Gregory P. Smith in
     gh-88168(12).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92248

   (2) https://github.com/python/cpython/issues/90953

   (3) https://github.com/python/cpython/issues/94597

   (4) https://github.com/python/cpython/issues/94597

   (5) https://github.com/python/cpython/issues/100160

   (6) https://github.com/python/cpython/issues/118767

   (7) https://github.com/python/cpython/issues/72346

   (8) https://github.com/python/cpython/issues/93963

   (9) https://github.com/python/cpython/issues/101588

   (10) https://github.com/python/cpython/issues/84559

   (11) https://github.com/python/cpython/issues/97850

   (12) https://github.com/python/cpython/issues/88168


File: python.info,  Node: Pending Removal in Python 3 15<3>,  Next: Pending removal in Python 3 16<3>,  Prev: Pending Removal in Python 3 14<3>,  Up: Deprecated

1.2.10.3 Pending Removal in Python 3.15
.......................................

   * The import system:

        * Setting *note __cached__: 2d5. on a module while failing to
          set *note __spec__.cached: 2d6. is deprecated.  In Python
          3.15, ‘__cached__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(1))

        * Setting *note __package__: 2d7. on a module while failing to
          set *note __spec__.parent: 2d8. is deprecated.  In Python
          3.15, ‘__package__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(2))

   * *note ctypes: 2a.:

        * The undocumented ‘ctypes.SetPointerType()’ function has been
          deprecated since Python 3.13.

   * *note http.server: 72.:

        * The obsolete and rarely used *note CGIHTTPRequestHandler: 2a1.
          has been deprecated since Python 3.13.  No direct replacement
          exists.  'Anything' is better than CGI to interface a web
          server with a request handler.

        * The ‘--cgi’ flag to the ‘python -m http.server’ command-line
          interface has been deprecated since Python 3.13.

   * *note importlib: 77.:

        * ‘load_module()’ method: use ‘exec_module()’ instead.

   * *note locale: 86.:

        * The *note getdefaultlocale(): 2d9. function has been
          deprecated since Python 3.11.  Its removal was originally
          planned for Python 3.13 (gh-90817(3)), but has been postponed
          to Python 3.15.  Use *note getlocale(): 2da, *note
          setlocale(): 2db, and *note getencoding(): 2dc. instead.
          (Contributed by Hugo van Kemenade in gh-111187(4).)

   * *note pathlib: a4.:

        * *note PurePath.is_reserved(): 2a6. has been deprecated since
          Python 3.13.  Use *note os.path.isreserved(): 223. to detect
          reserved paths on Windows.

   * *note platform: aa.:

        * *note java_ver(): 2a7. has been deprecated since Python 3.13.
          This function is only useful for Jython support, has a
          confusing API, and is largely untested.

   * *note sysconfig: db.:

        * The 'check_home' argument of *note
          sysconfig.is_python_build(): 2dd. has been deprecated since
          Python 3.12.

   * *note threading: ed.:

        * *note RLock(): 2de. will take no arguments in Python 3.15.
          Passing any arguments has been deprecated since Python 3.14,
          as the Python version does not permit any arguments, but the C
          version allows any number of positional or keyword arguments,
          ignoring every argument.

   * *note types: 103.:

        * *note types.CodeType: 2df.: Accessing *note co_lnotab: 2e0.
          was deprecated in PEP 626(5) since 3.10 and was planned to be
          removed in 3.12, but it only got a proper *note
          DeprecationWarning: 1a5. in 3.12.  May be removed in 3.15.
          (Contributed by Nikita Sobolev in gh-101866(6).)

   * *note typing: 104.:

        * The undocumented keyword argument syntax for creating *note
          NamedTuple: 2b0. classes (e.g.  ‘Point = NamedTuple("Point",
          x=int, y=int)’) has been deprecated since Python 3.13.  Use
          the class-based syntax or the functional syntax instead.

        * When using the functional syntax of *note TypedDict: 162.s,
          failing to pass a value to the 'fields' parameter (‘TD =
          TypedDict("TD")’) or passing ‘None’ (‘TD = TypedDict("TD",
          None)’) has been deprecated since Python 3.13.  Use ‘class
          TD(TypedDict): pass’ or ‘TD = TypedDict("TD", {})’ to create a
          TypedDict with zero field.

        * The *note typing.no_type_check_decorator(): 2b1. decorator
          function has been deprecated since Python 3.13.  After eight
          years in the *note typing: 104. module, it has yet to be
          supported by any major type checker.

   * *note wave: 113.:

        * The *note getmark(): 2b4, ‘setmark()’, and *note getmarkers():
          2b5. methods of the *note Wave_read: 2b6. and *note
          Wave_write: 2b7. classes have been deprecated since Python
          3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97879

   (2) https://github.com/python/cpython/issues/97879

   (3) https://github.com/python/cpython/issues/90817

   (4) https://github.com/python/cpython/issues/111187

   (5) https://peps.python.org/pep-0626/

   (6) https://github.com/python/cpython/issues/101866


File: python.info,  Node: Pending removal in Python 3 16<3>,  Next: Pending removal in Python 3 17<2>,  Prev: Pending Removal in Python 3 15<3>,  Up: Deprecated

1.2.10.4 Pending removal in Python 3.16
.......................................

   * The import system:

        * Setting *note __loader__: 2e2. on a module while failing to
          set *note __spec__.loader: 2e3. is deprecated.  In Python
          3.16, ‘__loader__’ will cease to be set or taken into
          consideration by the import system or the standard library.

   * *note array: 7.:

        * The ‘'u'’ format code (‘wchar_t’) has been deprecated in
          documentation since Python 3.3 and at runtime since Python
          3.13.  Use the ‘'w'’ format code (*note Py_UCS4: 29b.) for
          Unicode characters instead.

   * *note asyncio: a.:

        * ‘asyncio.iscoroutinefunction()’ is deprecated and will be
          removed in Python 3.16, use *note
          inspect.iscoroutinefunction(): 2e4. instead.  (Contributed by
          Jiahao Li and Kumar Aditya in gh-122875(1).)

   * *note builtins: 12.:

        * Bitwise inversion on boolean types, ‘~True’ or ‘~False’ has
          been deprecated since Python 3.12, as it produces surprising
          and unintuitive results (‘-2’ and ‘-1’).  Use ‘not x’ instead
          for the logical negation of a Boolean.  In the rare case that
          you need the bitwise inversion of the underlying integer,
          convert to ‘int’ explicitly (‘~int(x)’).

   * *note shutil: c5.:

        * The ‘ExecError’ exception has been deprecated since Python
          3.14.  It has not been used by any function in ‘shutil’ since
          Python 3.4, and is now an alias of *note RuntimeError: 195.

   * *note symtable: d8.:

        * The *note Class.get_methods: 2e5. method has been deprecated
          since Python 3.14.

   * *note sys: d9.:

        * The *note _enablelegacywindowsfsencoding(): 2ae. function has
          been deprecated since Python 3.13.  Use the *note
          PYTHONLEGACYWINDOWSFSENCODING: 2af. environment variable
          instead.

   * *note tarfile: de.:

        * The undocumented and unused ‘TarFile.tarfile’ attribute has
          been deprecated since Python 3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122875


File: python.info,  Node: Pending removal in Python 3 17<2>,  Next: Pending Removal in Future Versions<3>,  Prev: Pending removal in Python 3 16<3>,  Up: Deprecated

1.2.10.5 Pending removal in Python 3.17
.......................................

   * *note collections.abc: 1e.:

        - *note collections.abc.ByteString: 2e7. is scheduled for
          removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(1) for more details.  (Contributed by Shantanu
          Jain in gh-91896(2).)

   * *note typing: 104.:

        - Before Python 3.14, old-style unions were implemented using
          the private class ‘typing._UnionGenericAlias’.  This class is
          no longer needed for the implementation, but it has been
          retained for backward compatibility, with removal scheduled
          for Python 3.17.  Users should use documented introspection
          helpers like *note typing.get_origin(): 2ec. and *note
          typing.get_args(): 2ed. instead of relying on private
          implementation details.

        - *note typing.ByteString: 2ee, deprecated since Python 3.9, is
          scheduled for removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(3) for more details.  (Contributed by Shantanu
          Jain in gh-91896(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0688/#current-options

   (2) https://github.com/python/cpython/issues/91896

   (3) https://peps.python.org/pep-0688/#current-options

   (4) https://github.com/python/cpython/issues/91896


File: python.info,  Node: Pending Removal in Future Versions<3>,  Prev: Pending removal in Python 3 17<2>,  Up: Deprecated

1.2.10.6 Pending Removal in Future Versions
...........................................

The following APIs will be removed in the future, although there is
currently no date scheduled for their removal.

   * *note argparse: 6.: Nesting argument groups and nesting mutually
     exclusive groups are deprecated.

   * *note builtins: 12.:

        * Generators: ‘throw(type, exc, tb)’ and ‘athrow(type, exc, tb)’
          signature is deprecated: use ‘throw(exc)’ and ‘athrow(exc)’
          instead, the single argument signature.

        * Currently Python accepts numeric literals immediately followed
          by keywords, for example ‘0in x’, ‘1or x’, ‘0if 1else 2’.  It
          allows confusing and ambiguous expressions like ‘[0x1for x in
          y]’ (which can be interpreted as ‘[0x1 for x in y]’ or ‘[0x1f
          or x in y]’).  A syntax warning is raised if the numeric
          literal is immediately followed by one of keywords *note and:
          2f1, *note else: 18c, *note for: 2f2, *note if: 2f3, *note in:
          2f4, *note is: 2f5. and *note or: 2f6.  In a future release it
          will be changed to a syntax error.  (gh-87999(1))

        * Support for ‘__index__()’ and ‘__int__()’ method returning
          non-int type: these methods will be required to return an
          instance of a strict subclass of *note int: 257.

        * Support for ‘__float__()’ method returning a strict subclass
          of *note float: 2f7.: these methods will be required to return
          an instance of ‘float’.

        * Support for ‘__complex__()’ method returning a strict subclass
          of *note complex: 2f8.: these methods will be required to
          return an instance of ‘complex’.

        * Delegation of ‘int()’ to ‘__trunc__()’ method.

        * Passing a complex number as the 'real' or 'imag' argument in
          the *note complex(): 2f8. constructor is now deprecated; it
          should only be passed as a single positional argument.
          (Contributed by Serhiy Storchaka in gh-109218(2).)

   * *note calendar: 14.: ‘calendar.January’ and ‘calendar.February’
     constants are deprecated and replaced by *note calendar.JANUARY:
     2f9. and *note calendar.FEBRUARY: 2fa.  (Contributed by Prince
     Roshan in gh-103636(3).)

   * *note codeobject.co_lnotab: 2e0.: use the *note
     codeobject.co_lines(): 2fb. method instead.

   * *note datetime: 30.:

        * *note utcnow(): 2fc.: use
          ‘datetime.datetime.now(tz=datetime.UTC)’.

        * *note utcfromtimestamp(): 2fd.: use
          ‘datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)’.

   * *note gettext: 63.: Plural value must be an integer.

   * *note importlib: 77.:

        * *note cache_from_source(): 2fe. 'debug_override' parameter is
          deprecated: use the 'optimization' parameter instead.

   * *note importlib.metadata: 7a.:

        * ‘EntryPoints’ tuple interface.

        * Implicit ‘None’ on return values.

   * *note logging: 87.: the ‘warn()’ method has been deprecated since
     Python 3.3, use *note warning(): 2ff. instead.

   * *note mailbox: 8b.: Use of StringIO input and text mode is
     deprecated, use BytesIO and binary mode instead.

   * *note os: a1.: Calling *note os.register_at_fork(): 300. in
     multi-threaded process.

   * ‘pydoc.ErrorDuringImport’: A tuple value for 'exc_info' parameter
     is deprecated, use an exception instance.

   * *note re: b9.: More strict rules are now applied for numerical
     group references and group names in regular expressions.  Only
     sequence of ASCII digits is now accepted as a numerical reference.
     The group name in bytes patterns and replacement strings can now
     only contain ASCII letters and digits and underscore.  (Contributed
     by Serhiy Storchaka in gh-91760(4).)

   * ‘sre_compile’, ‘sre_constants’ and ‘sre_parse’ modules.

   * *note shutil: c5.: *note rmtree(): 301.’s 'onerror' parameter is
     deprecated in Python 3.12; use the 'onexc' parameter instead.

   * *note ssl: d0. options and protocols:

        * *note ssl.SSLContext: 294. without protocol argument is
          deprecated.

        * *note ssl.SSLContext: 294.: *note set_npn_protocols(): 302.
          and ‘selected_npn_protocol()’ are deprecated: use ALPN
          instead.

        * ‘ssl.OP_NO_SSL*’ options

        * ‘ssl.OP_NO_TLS*’ options

        * ‘ssl.PROTOCOL_SSLv3’

        * ‘ssl.PROTOCOL_TLS’

        * ‘ssl.PROTOCOL_TLSv1’

        * ‘ssl.PROTOCOL_TLSv1_1’

        * ‘ssl.PROTOCOL_TLSv1_2’

        * ‘ssl.TLSVersion.SSLv3’

        * ‘ssl.TLSVersion.TLSv1’

        * ‘ssl.TLSVersion.TLSv1_1’

   * *note threading: ed. methods:

        * ‘threading.Condition.notifyAll()’: use *note notify_all():
          303.

        * ‘threading.Event.isSet()’: use *note is_set(): 304.

        * ‘threading.Thread.isDaemon()’, *note
          threading.Thread.setDaemon(): 305.: use *note
          threading.Thread.daemon: 306. attribute.

        * ‘threading.Thread.getName()’, *note
          threading.Thread.setName(): 307.: use *note
          threading.Thread.name: 308. attribute.

        * ‘threading.currentThread()’: use *note
          threading.current_thread(): 309.

        * ‘threading.activeCount()’: use *note threading.active_count():
          30a.

   * *note typing.Text: 30b. (gh-92332(5)).

   * *note unittest.IsolatedAsyncioTestCase: 30c.: it is deprecated to
     return a value that is not ‘None’ from a test case.

   * *note urllib.parse: 10a. deprecated functions: *note urlparse():
     30d. instead

        * ‘splitattr()’

        * ‘splithost()’

        * ‘splitnport()’

        * ‘splitpasswd()’

        * ‘splitport()’

        * ‘splitquery()’

        * ‘splittag()’

        * ‘splittype()’

        * ‘splituser()’

        * ‘splitvalue()’

        * ‘to_bytes()’

   * *note urllib.request: 10b.: *note URLopener: 30e. and *note
     FancyURLopener: 30f. style of invoking requests is deprecated.  Use
     newer *note urlopen(): 293. functions and methods.

   * *note wsgiref: 118.: ‘SimpleHandler.stdout.write()’ should not do
     partial writes.

   * *note xml.etree.ElementTree: 125.: Testing the truth value of an
     *note Element: 310. is deprecated.  In a future release it will
     always return ‘True’.  Prefer explicit ‘len(elem)’ or ‘elem is not
     None’ tests instead.

   * *note zipimport.zipimporter.load_module(): 311. is deprecated: use
     *note exec_module(): 312. instead.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87999

   (2) https://github.com/python/cpython/issues/109218

   (3) https://github.com/python/cpython/issues/103636

   (4) https://github.com/python/cpython/issues/91760

   (5) https://github.com/python/cpython/issues/92332


File: python.info,  Node: Removed,  Next: Porting to Python 3 12,  Prev: Deprecated,  Up: What’s New In Python 3 12

1.2.11 Removed
--------------

* Menu:

* asynchat and asyncore::
* configparser: configparser<3>.
* distutils::
* ensurepip::
* enum: enum<2>.
* ftplib::
* gzip::
* hashlib::
* importlib: importlib<2>.
* imp::
* io: io<2>.
* locale: locale<2>.
* smtpd::
* sqlite3: sqlite3<3>.
* ssl: ssl<2>.
* unittest: unittest<3>.
* webbrowser: webbrowser<2>.
* xml.etree.ElementTree: xml etree ElementTree.
* zipimport: zipimport<2>.
* Others::


File: python.info,  Node: asynchat and asyncore,  Next: configparser<3>,  Up: Removed

1.2.11.1 asynchat and asyncore
..............................

   * These two modules have been removed according to the schedule in
     PEP 594(1), having been deprecated in Python 3.6.  Use *note
     asyncio: a. instead.  (Contributed by Nikita Sobolev in
     gh-96580(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://github.com/python/cpython/issues/96580


File: python.info,  Node: configparser<3>,  Next: distutils,  Prev: asynchat and asyncore,  Up: Removed

1.2.11.2 configparser
.....................

   * Several names deprecated in the *note configparser: 22. way back in
     3.2 have been removed per gh-89336(1):

        * *note configparser.ParsingError: 508. no longer has a
          ‘filename’ attribute or argument.  Use the ‘source’ attribute
          and argument instead.

        * *note configparser: 22. no longer has a ‘SafeConfigParser’
          class.  Use the shorter *note ConfigParser: 1c8. name instead.

        * *note configparser.ConfigParser: 1c8. no longer has a ‘readfp’
          method.  Use *note read_file(): 509. instead.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89336


File: python.info,  Node: distutils,  Next: ensurepip,  Prev: configparser<3>,  Up: Removed

1.2.11.3 distutils
..................

   * Remove the ‘distutils’ package.  It was deprecated in Python 3.10
     by PEP 632(1) “Deprecate distutils module”.  For projects still
     using ‘distutils’ and cannot be updated to something else, the
     ‘setuptools’ project can be installed: it still provides
     ‘distutils’.  (Contributed by Victor Stinner in gh-92584(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0632/

   (2) https://github.com/python/cpython/issues/92584


File: python.info,  Node: ensurepip,  Next: enum<2>,  Prev: distutils,  Up: Removed

1.2.11.4 ensurepip
..................

   * Remove the bundled setuptools wheel from *note ensurepip: 55, and
     stop installing setuptools in environments created by *note venv:
     111.

     ‘pip (>= 22.1)’ does not require setuptools to be installed in the
     environment.  ‘setuptools’-based (and ‘distutils’-based) packages
     can still be used with ‘pip install’, since pip will provide
     ‘setuptools’ in the build environment it uses for building a
     package.

     ‘easy_install’, ‘pkg_resources’, ‘setuptools’ and ‘distutils’ are
     no longer provided by default in environments created with ‘venv’
     or bootstrapped with ‘ensurepip’, since they are part of the
     ‘setuptools’ package.  For projects relying on these at runtime,
     the ‘setuptools’ project should be declared as a dependency and
     installed separately (typically, using pip).

     (Contributed by Pradyun Gedam in gh-95299(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95299


File: python.info,  Node: enum<2>,  Next: ftplib,  Prev: ensurepip,  Up: Removed

1.2.11.5 enum
.............

   * Remove *note enum: 56.’s ‘EnumMeta.__getattr__’, which is no longer
     needed for enum attribute access.  (Contributed by Ethan Furman in
     gh-95083(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95083


File: python.info,  Node: ftplib,  Next: gzip,  Prev: enum<2>,  Up: Removed

1.2.11.6 ftplib
...............

   * Remove *note ftplib: 5e.’s ‘FTP_TLS.ssl_version’ class attribute:
     use the 'context' parameter instead.  (Contributed by Victor
     Stinner in gh-94172(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94172


File: python.info,  Node: gzip,  Next: hashlib,  Prev: ftplib,  Up: Removed

1.2.11.7 gzip
.............

   * Remove the ‘filename’ attribute of *note gzip: 67.’s *note
     gzip.GzipFile: 41d, deprecated since Python 2.6, use the *note
     name: 510. attribute instead.  In write mode, the ‘filename’
     attribute added ‘'.gz'’ file extension if it was not present.
     (Contributed by Victor Stinner in gh-94196(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94196


File: python.info,  Node: hashlib,  Next: importlib<2>,  Prev: gzip,  Up: Removed

1.2.11.8 hashlib
................

   * Remove the pure Python implementation of *note hashlib: 68.’s *note
     hashlib.pbkdf2_hmac(): 512, deprecated in Python 3.10.  Python 3.10
     and newer requires OpenSSL 1.1.1 ( PEP 644(1)): this OpenSSL
     version provides a C implementation of ‘pbkdf2_hmac()’ which is
     faster.  (Contributed by Victor Stinner in gh-94199(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0644/

   (2) https://github.com/python/cpython/issues/94199


File: python.info,  Node: importlib<2>,  Next: imp,  Prev: hashlib,  Up: Removed

1.2.11.9 importlib
..................

   * Many previously deprecated cleanups in *note importlib: 77. have
     now been completed:

        * References to, and support for ‘module_repr()’ has been
          removed.  (Contributed by Barry Warsaw in gh-97850(1).)

        * ‘importlib.util.set_package’, ‘importlib.util.set_loader’ and
          ‘importlib.util.module_for_loader’ have all been removed.
          (Contributed by Brett Cannon and Nikita Sobolev in gh-65961(2)
          and gh-97850(3).)

        * Support for ‘find_loader()’ and ‘find_module()’ APIs have been
          removed.  (Contributed by Barry Warsaw in gh-98040(4).)

        * ‘importlib.abc.Finder’, ‘pkgutil.ImpImporter’, and
          ‘pkgutil.ImpLoader’ have been removed.  (Contributed by Barry
          Warsaw in gh-98040(5).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97850

   (2) https://github.com/python/cpython/issues/65961

   (3) https://github.com/python/cpython/issues/97850

   (4) https://github.com/python/cpython/issues/98040

   (5) https://github.com/python/cpython/issues/98040


File: python.info,  Node: imp,  Next: io<2>,  Prev: importlib<2>,  Up: Removed

1.2.11.10 imp
.............

   * The ‘imp’ module has been removed.  (Contributed by Barry Warsaw in
     gh-98040(1).)

     To migrate, consult the following correspondence table:

          imp                                   importlib
                                                
          --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                
          ‘imp.NullImporter’                    Insert ‘None’ into ‘sys.path_importer_cache’
                                                
                                                
          ‘imp.cache_from_source()’             *note importlib.util.cache_from_source(): 2fe.
                                                
                                                
          ‘imp.find_module()’                   *note importlib.util.find_spec(): 2cd.
                                                
                                                
          ‘imp.get_magic()’                     *note importlib.util.MAGIC_NUMBER: 516.
                                                
                                                
          ‘imp.get_suffixes()’                  *note importlib.machinery.SOURCE_SUFFIXES: 517, *note importlib.machinery.EXTENSION_SUFFIXES: 518, and
                                                *note importlib.machinery.BYTECODE_SUFFIXES: 519.
                                                
                                                
          ‘imp.get_tag()’                       *note sys.implementation.cache_tag: 51a.
                                                
                                                
          ‘imp.load_module()’                   *note importlib.import_module(): 51b.
                                                
                                                
          ‘imp.new_module(name)’                ‘types.ModuleType(name)’
                                                
                                                
          ‘imp.reload()’                        *note importlib.reload(): 51c.
                                                
                                                
          ‘imp.source_from_cache()’             *note importlib.util.source_from_cache(): 51d.
                                                
                                                
          ‘imp.load_source()’                   'See below'
                                                

     Replace ‘imp.load_source()’ with:

          import importlib.util
          import importlib.machinery

          def load_source(modname, filename):
              loader = importlib.machinery.SourceFileLoader(modname, filename)
              spec = importlib.util.spec_from_file_location(modname, filename, loader=loader)
              module = importlib.util.module_from_spec(spec)
              # The module is always executed and not cached in sys.modules.
              # Uncomment the following line to cache the module.
              # sys.modules[module.__name__] = module
              loader.exec_module(module)
              return module

   * Remove ‘imp’ functions and attributes with no replacements:

        * Undocumented functions:

             * ‘imp.init_builtin()’

             * ‘imp.load_compiled()’

             * ‘imp.load_dynamic()’

             * ‘imp.load_package()’

        * ‘imp.lock_held()’, ‘imp.acquire_lock()’, ‘imp.release_lock()’:
          the locking scheme has changed in Python 3.3 to per-module
          locks.

        * ‘imp.find_module()’ constants: ‘SEARCH_ERROR’, ‘PY_SOURCE’,
          ‘PY_COMPILED’, ‘C_EXTENSION’, ‘PY_RESOURCE’, ‘PKG_DIRECTORY’,
          ‘C_BUILTIN’, ‘PY_FROZEN’, ‘PY_CODERESOURCE’, ‘IMP_HOOK’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98040


File: python.info,  Node: io<2>,  Next: locale<2>,  Prev: imp,  Up: Removed

1.2.11.11 io
............

   * Remove *note io: 7f.’s ‘io.OpenWrapper’ and ‘_pyio.OpenWrapper’,
     deprecated in Python 3.10: just use *note open(): 51f. instead.
     The ‘open()’ (*note io.open(): 520.) function is a built-in
     function.  Since Python 3.10, ‘_pyio.open()’ is also a static
     method.  (Contributed by Victor Stinner in gh-94169(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94169


File: python.info,  Node: locale<2>,  Next: smtpd,  Prev: io<2>,  Up: Removed

1.2.11.12 locale
................

   * Remove *note locale: 86.’s ‘locale.format()’ function, deprecated
     in Python 3.7: use *note locale.format_string(): 522. instead.
     (Contributed by Victor Stinner in gh-94226(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94226


File: python.info,  Node: smtpd,  Next: sqlite3<3>,  Prev: locale<2>,  Up: Removed

1.2.11.13 smtpd
...............

   * The ‘smtpd’ module has been removed according to the schedule in
     PEP 594(1), having been deprecated in Python 3.4.7 and 3.5.4.  Use
     the aiosmtpd(2) PyPI module or any other *note asyncio: a.-based
     server instead.  (Contributed by Oleg Iarygin in gh-93243(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/aiosmtpd/

   (3) https://github.com/python/cpython/issues/93243


File: python.info,  Node: sqlite3<3>,  Next: ssl<2>,  Prev: smtpd,  Up: Removed

1.2.11.14 sqlite3
.................

   * The following undocumented *note sqlite3: cf. features, deprecated
     in Python 3.10, are now removed:

        * ‘sqlite3.enable_shared_cache()’

        * ‘sqlite3.OptimizedUnicode’

     If a shared cache must be used, open the database in URI mode using
     the ‘cache=shared’ query parameter.

     The ‘sqlite3.OptimizedUnicode’ text factory has been an alias for
     *note str: 44f. since Python 3.3.  Code that previously set the
     text factory to ‘OptimizedUnicode’ can either use ‘str’ explicitly,
     or rely on the default value which is also ‘str’.

     (Contributed by Erlend E. Aasland in gh-92548(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92548


File: python.info,  Node: ssl<2>,  Next: unittest<3>,  Prev: sqlite3<3>,  Up: Removed

1.2.11.15 ssl
.............

   * Remove *note ssl: d0.’s ‘ssl.RAND_pseudo_bytes()’ function,
     deprecated in Python 3.6: use *note os.urandom(): 526. or *note
     ssl.RAND_bytes(): 527. instead.  (Contributed by Victor Stinner in
     gh-94199(1).)

   * Remove the ‘ssl.match_hostname()’ function.  It was deprecated in
     Python 3.7.  OpenSSL performs hostname matching since Python 3.7,
     Python no longer uses the ‘ssl.match_hostname()’ function.
     (Contributed by Victor Stinner in gh-94199(2).)

   * Remove the ‘ssl.wrap_socket()’ function, deprecated in Python 3.7:
     instead, create a *note ssl.SSLContext: 294. object and call its
     *note ssl.SSLContext.wrap_socket: 528. method.  Any package that
     still uses ‘ssl.wrap_socket()’ is broken and insecure.  The
     function neither sends a SNI TLS extension nor validates the server
     hostname.  Code is subject to CWE 295(3) (Improper Certificate
     Validation).  (Contributed by Victor Stinner in gh-94199(4).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94199

   (2) https://github.com/python/cpython/issues/94199

   (3) https://cwe.mitre.org/data/definitions/295.html

   (4) https://github.com/python/cpython/issues/94199


File: python.info,  Node: unittest<3>,  Next: webbrowser<2>,  Prev: ssl<2>,  Up: Removed

1.2.11.16 unittest
..................

   * Remove many long-deprecated *note unittest: 106. features:

        * A number of *note TestCase: 451. method aliases:

          Deprecated alias                 Method Name                         Deprecated in
                                                                               
          -----------------------------------------------------------------------------------------
                                                                               
          ‘failUnless’                     *note assertTrue(): 52a.            3.1
                                                                               
                                                                               
          ‘failIf’                         *note assertFalse(): 52b.           3.1
                                                                               
                                                                               
          ‘failUnlessEqual’                *note assertEqual(): 52c.           3.1
                                                                               
                                                                               
          ‘failIfEqual’                    *note assertNotEqual(): 52d.        3.1
                                                                               
                                                                               
          ‘failUnlessAlmostEqual’          *note assertAlmostEqual(): 52e.     3.1
                                                                               
                                                                               
          ‘failIfAlmostEqual’              *note assertNotAlmostEqual(): 52f.  3.1
                                                                               
                                                                               
          ‘failUnlessRaises’               *note assertRaises(): 530.          3.1
                                                                               
                                                                               
          ‘assert_’                        *note assertTrue(): 52a.            3.2
                                                                               
                                                                               
          ‘assertEquals’                   *note assertEqual(): 52c.           3.2
                                                                               
                                                                               
          ‘assertNotEquals’                *note assertNotEqual(): 52d.        3.2
                                                                               
                                                                               
          ‘assertAlmostEquals’             *note assertAlmostEqual(): 52e.     3.2
                                                                               
                                                                               
          ‘assertNotAlmostEquals’          *note assertNotAlmostEqual(): 52f.  3.2
                                                                               
                                                                               
          ‘assertRegexpMatches’            *note assertRegex(): 531.           3.2
                                                                               
                                                                               
          ‘assertRaisesRegexp’             *note assertRaisesRegex(): 532.     3.2
                                                                               
                                                                               
          ‘assertNotRegexpMatches’         *note assertNotRegex(): 533.        3.5
                                                                               

          You can use ‘https://github.com/isidentical/teyit’ to
          automatically modernise your unit tests.

        * Undocumented and broken *note TestCase: 451. method
          ‘assertDictContainsSubset’ (deprecated in Python 3.2).

        * Undocumented *note TestLoader.loadTestsFromModule: 28f.
          parameter 'use_load_tests' (deprecated and ignored since
          Python 3.5).

        * An alias of the *note TextTestResult: 534. class:
          ‘_TextTestResult’ (deprecated in Python 3.2).

     (Contributed by Serhiy Storchaka in gh-89325(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89325


File: python.info,  Node: webbrowser<2>,  Next: xml etree ElementTree,  Prev: unittest<3>,  Up: Removed

1.2.11.17 webbrowser
....................

   * Remove support for obsolete browsers from *note webbrowser: 115.
     The removed browsers include: Grail, Mosaic, Netscape, Galeon,
     Skipstone, Iceape, Firebird, and Firefox versions 35 and below
     (gh-102871(1)).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102871


File: python.info,  Node: xml etree ElementTree,  Next: zipimport<2>,  Prev: webbrowser<2>,  Up: Removed

1.2.11.18 xml.etree.ElementTree
...............................

   * Remove the ‘ElementTree.Element.copy()’ method of the pure Python
     implementation, deprecated in Python 3.10, use the *note
     copy.copy(): 537. function instead.  The C implementation of *note
     xml.etree.ElementTree: 125. has no ‘copy()’ method, only a
     ‘__copy__()’ method.  (Contributed by Victor Stinner in
     gh-94383(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94383


File: python.info,  Node: zipimport<2>,  Next: Others,  Prev: xml etree ElementTree,  Up: Removed

1.2.11.19 zipimport
...................

   * Remove *note zipimport: 132.’s ‘find_loader()’ and ‘find_module()’
     methods, deprecated in Python 3.10: use the ‘find_spec()’ method
     instead.  See PEP 451(1) for the rationale.  (Contributed by Victor
     Stinner in gh-94379(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0451/

   (2) https://github.com/python/cpython/issues/94379


File: python.info,  Node: Others,  Prev: zipimport<2>,  Up: Removed

1.2.11.20 Others
................

   * Remove the ‘suspicious’ rule from the documentation ‘Makefile’ and
     ‘Doc/tools/rstlint.py’, both in favor of sphinx-lint(1).
     (Contributed by Julien Palard in gh-98179(2).)

   * Remove the 'keyfile' and 'certfile' parameters from the *note
     ftplib: 5e, *note imaplib: 74, *note poplib: ac. and *note smtplib:
     ca. modules, and the 'key_file', 'cert_file' and 'check_hostname'
     parameters from the *note http.client: 6f. module, all deprecated
     since Python 3.6.  Use the 'context' parameter ('ssl_context' in
     ‘imaplib’) instead.  (Contributed by Victor Stinner in
     gh-94172(3).)

   * Remove ‘Jython’ compatibility hacks from several stdlib modules and
     tests.  (Contributed by Nikita Sobolev in gh-99482(4).)

   * Remove ‘_use_broken_old_ctypes_structure_semantics_’ flag from
     *note ctypes: 2a. module.  (Contributed by Nikita Sobolev in
     gh-99285(5).)

   ---------- Footnotes ----------

   (1) https://github.com/sphinx-contrib/sphinx-lint

   (2) https://github.com/python/cpython/issues/98179

   (3) https://github.com/python/cpython/issues/94172

   (4) https://github.com/python/cpython/issues/99482

   (5) https://github.com/python/cpython/issues/99285


File: python.info,  Node: Porting to Python 3 12,  Next: Build Changes<2>,  Prev: Removed,  Up: What’s New In Python 3 12

1.2.12 Porting to Python 3.12
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in the Python API: Changes in the Python API<2>.


File: python.info,  Node: Changes in the Python API<2>,  Up: Porting to Python 3 12

1.2.12.1 Changes in the Python API
..................................

   * More strict rules are now applied for numerical group references
     and group names in regular expressions.  Only sequence of ASCII
     digits is now accepted as a numerical reference.  The group name in
     bytes patterns and replacement strings can now only contain ASCII
     letters and digits and underscore.  (Contributed by Serhiy
     Storchaka in gh-91760(1).)

   * Remove ‘randrange()’ functionality deprecated since Python 3.10.
     Formerly, ‘randrange(10.0)’ losslessly converted to
     ‘randrange(10)’.  Now, it raises a *note TypeError: 2c3.  Also, the
     exception raised for non-integer values such as ‘randrange(10.5)’
     or ‘randrange('10')’ has been changed from *note ValueError: 202.
     to ‘TypeError’.  This also prevents bugs where ‘randrange(1e25)’
     would silently select from a larger range than ‘randrange(10**25)’.
     (Originally suggested by Serhiy Storchaka gh-86388(2).)

   * *note argparse.ArgumentParser: 53c. changed encoding and error
     handler for reading arguments from file (e.g.
     ‘fromfile_prefix_chars’ option) from default text encoding (e.g.
     *note locale.getpreferredencoding(False): 53d.) to *note filesystem
     encoding and error handler: 53e.  Argument files should be encoded
     in UTF-8 instead of ANSI Codepage on Windows.

   * Remove the ‘asyncore’-based ‘smtpd’ module deprecated in Python
     3.4.7 and 3.5.4.  A recommended replacement is the *note asyncio:
     a.-based aiosmtpd(3) PyPI module.

   * *note shlex.split(): 53f.: Passing ‘None’ for 's' argument now
     raises an exception, rather than reading *note sys.stdin: 540.  The
     feature was deprecated in Python 3.9.  (Contributed by Victor
     Stinner in gh-94352(4).)

   * The *note os: a1. module no longer accepts bytes-like paths, like
     *note bytearray: 2ea. and *note memoryview: 2eb. types: only the
     exact *note bytes: 1c2. type is accepted for bytes strings.
     (Contributed by Victor Stinner in gh-98393(5).)

   * *note syslog.openlog(): 541. and *note syslog.closelog(): 542. now
     fail if used in subinterpreters.  *note syslog.syslog(): 543. may
     still be used in subinterpreters, but now only if
     ‘syslog.openlog()’ has already been called in the main interpreter.
     These new restrictions do not apply to the main interpreter, so
     only a very small set of users might be affected.  This change
     helps with interpreter isolation.  Furthermore, *note syslog: dc.
     is a wrapper around process-global resources, which are best
     managed from the main interpreter.  (Contributed by Donghee Na in
     gh-99127(6).)

   * The undocumented locking behavior of *note cached_property(): 544.
     is removed, because it locked across all instances of the class,
     leading to high lock contention.  This means that a cached property
     getter function could now run more than once for a single instance,
     if two threads race.  For most simple cached properties (e.g.
     those that are idempotent and simply calculate a value based on
     other attributes of the instance) this will be fine.  If
     synchronization is needed, implement locking within the cached
     property getter function or around multi-threaded access points.

   * *note sys._current_exceptions(): 4c5. now returns a mapping from
     thread-id to an exception instance, rather than to a ‘(typ, exc,
     tb)’ tuple.  (Contributed by Irit Katriel in gh-103176(7).)

   * When extracting tar files using *note tarfile: de. or *note
     shutil.unpack_archive(): 46e, pass the 'filter' argument to limit
     features that may be surprising or dangerous.  See *note Extraction
     filters: 46f. for details.

   * The output of the *note tokenize.tokenize(): 4dc. and *note
     tokenize.generate_tokens(): 4dd. functions is now changed due to
     the changes introduced in PEP 701(8).  This means that ‘STRING’
     tokens are not emitted any more for f-strings and the tokens
     described in PEP 701(9) are now produced instead: ‘FSTRING_START’,
     ‘FSTRING_MIDDLE’ and ‘FSTRING_END’ are now emitted for f-string
     “string” parts in addition to the appropriate tokens for the
     tokenization in the expression components.  For example for the
     f-string ‘f"start {1+1} end"’ the old version of the tokenizer
     emitted:

          1,0-1,18:           STRING         'f"start {1+1} end"'

     while the new version emits:

          1,0-1,2:            FSTRING_START  'f"'
          1,2-1,8:            FSTRING_MIDDLE 'start '
          1,8-1,9:            OP             '{'
          1,9-1,10:           NUMBER         '1'
          1,10-1,11:          OP             '+'
          1,11-1,12:          NUMBER         '1'
          1,12-1,13:          OP             '}'
          1,13-1,17:          FSTRING_MIDDLE ' end'
          1,17-1,18:          FSTRING_END    '"'

     Additionally, there may be some minor behavioral changes as a
     consequence of the changes required to support PEP 701(10).  Some
     of these changes include:

        * The ‘type’ attribute of the tokens emitted when tokenizing
          some invalid Python characters such as ‘!’ has changed from
          ‘ERRORTOKEN’ to ‘OP’.

        * Incomplete single-line strings now also raise *note
          tokenize.TokenError: 545. as incomplete multiline strings do.

        * Some incomplete or invalid Python code now raises *note
          tokenize.TokenError: 545. instead of returning arbitrary
          ‘ERRORTOKEN’ tokens when tokenizing it.

        * Mixing tabs and spaces as indentation in the same file is not
          supported anymore and will raise a *note TabError: 546.

   * The *note threading: ed. module now expects the ‘_thread’ module to
     have an ‘_is_main_interpreter’ attribute.  It is a function with no
     arguments that returns ‘True’ if the current interpreter is the
     main interpreter.

     Any library or application that provides a custom ‘_thread’ module
     should provide ‘_is_main_interpreter()’.  (See gh-112826(11).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91760

   (2) https://github.com/python/cpython/issues/86388

   (3) https://pypi.org/project/aiosmtpd/

   (4) https://github.com/python/cpython/issues/94352

   (5) https://github.com/python/cpython/issues/98393

   (6) https://github.com/python/cpython/issues/99127

   (7) https://github.com/python/cpython/issues/103176

   (8) https://peps.python.org/pep-0701/

   (9) https://peps.python.org/pep-0701/

   (10) https://peps.python.org/pep-0701/

   (11) https://github.com/python/cpython/issues/112826


File: python.info,  Node: Build Changes<2>,  Next: C API Changes<2>,  Prev: Porting to Python 3 12,  Up: What’s New In Python 3 12

1.2.13 Build Changes
--------------------

   * Python no longer uses ‘setup.py’ to build shared C extension
     modules.  Build parameters like headers and libraries are detected
     in ‘configure’ script.  Extensions are built by ‘Makefile’.  Most
     extensions use ‘pkg-config’ and fall back to manual detection.
     (Contributed by Christian Heimes in gh-93939(1).)

   * ‘va_start()’ with two parameters, like ‘va_start(args, format),’ is
     now required to build Python.  ‘va_start()’ is no longer called
     with a single parameter.  (Contributed by Kumar Aditya in
     gh-93207(2).)

   * CPython now uses the ThinLTO option as the default link time
     optimization policy if the Clang compiler accepts the flag.
     (Contributed by Donghee Na in gh-89536(3).)

   * Add ‘COMPILEALL_OPTS’ variable in ‘Makefile’ to override *note
     compileall: 20. options (default: ‘-j0’) in ‘make install’.  Also
     merged the 3 ‘compileall’ commands into a single command to build
     .pyc files for all optimization levels (0, 1, 2) at once.
     (Contributed by Victor Stinner in gh-99289(4).)

   * Add platform triplets for 64-bit LoongArch:

        * loongarch64-linux-gnusf

        * loongarch64-linux-gnuf32

        * loongarch64-linux-gnu

     (Contributed by Zhang Na in gh-90656(5).)

   * ‘PYTHON_FOR_REGEN’ now require Python 3.10 or newer.

   * Autoconf 2.71 and aclocal 1.16.4 is now required to regenerate
     ‘!configure’.  (Contributed by Christian Heimes in gh-89886(6).)

   * Windows builds and macOS installers from python.org now use OpenSSL
     3.0.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93939

   (2) https://github.com/python/cpython/issues/93207

   (3) https://github.com/python/cpython/issues/89536

   (4) https://github.com/python/cpython/issues/99289

   (5) https://github.com/python/cpython/issues/90656

   (6) https://github.com/python/cpython/issues/89886


File: python.info,  Node: C API Changes<2>,  Prev: Build Changes<2>,  Up: What’s New In Python 3 12

1.2.14 C API Changes
--------------------

* Menu:

* New Features: New Features<4>.
* Porting to Python 3.12: Porting to Python 3 12<2>.
* Deprecated: Deprecated<2>.
* Removed: Removed<2>.


File: python.info,  Node: New Features<4>,  Next: Porting to Python 3 12<2>,  Up: C API Changes<2>

1.2.14.1 New Features
.....................

   * PEP 697(1): Introduce the *note Unstable C API tier: 54a, intended
     for low-level tools like debuggers and JIT compilers.  This API may
     change in each minor release of CPython without deprecation
     warnings.  Its contents are marked by the ‘PyUnstable_’ prefix in
     names.

     Code object constructors:

        - ‘PyUnstable_Code_New()’ (renamed from ‘PyCode_New’)

        - ‘PyUnstable_Code_NewWithPosOnlyArgs()’ (renamed from
          ‘PyCode_NewWithPosOnlyArgs’)

     Extra storage for code objects ( PEP 523(2)):

        - ‘PyUnstable_Eval_RequestCodeExtraIndex()’ (renamed from
          ‘_PyEval_RequestCodeExtraIndex’)

        - ‘PyUnstable_Code_GetExtra()’ (renamed from ‘_PyCode_GetExtra’)

        - ‘PyUnstable_Code_SetExtra()’ (renamed from ‘_PyCode_SetExtra’)

     The original names will continue to be available until the
     respective API changes.

     (Contributed by Petr Viktorin in gh-101101(3).)

   * PEP 697(4): Add an API for extending types whose instance memory
     layout is opaque:

        - *note PyType_Spec.basicsize: 54b. can be zero or negative to
          specify inheriting or extending the base class size.

        - *note PyObject_GetTypeData(): 54c. and *note
          PyType_GetTypeDataSize(): 54d. added to allow access to
          subclass-specific instance data.

        - *note Py_TPFLAGS_ITEMS_AT_END: 54e. and *note
          PyObject_GetItemData(): 54f. added to allow safely extending
          certain variable-sized types, including *note PyType_Type:
          550.

        - *note Py_RELATIVE_OFFSET: 551. added to allow defining *note
          members: 552. in terms of a subclass-specific struct.

     (Contributed by Petr Viktorin in gh-103509(5).)

   * Add the new *note limited C API: 399. function *note
     PyType_FromMetaclass(): 553, which generalizes the existing *note
     PyType_FromModuleAndSpec(): 554. using an additional metaclass
     argument.  (Contributed by Wenzel Jakob in gh-93012(6).)

   * API for creating objects that can be called using *note the
     vectorcall protocol: 555. was added to the *note Limited API: 556.:

        * *note Py_TPFLAGS_HAVE_VECTORCALL: 557.

        * *note PyVectorcall_NARGS(): 558.

        * *note PyVectorcall_Call(): 559.

        * *note vectorcallfunc: 55a.

     The *note Py_TPFLAGS_HAVE_VECTORCALL: 557. flag is now removed from
     a class when the class’s *note __call__(): 55b. method is
     reassigned.  This makes vectorcall safe to use with mutable types
     (i.e.  heap types without the immutable flag, *note
     Py_TPFLAGS_IMMUTABLETYPE: 3c5.).  Mutable types that do not
     override *note tp_call: 55c. now inherit the
     ‘Py_TPFLAGS_HAVE_VECTORCALL’ flag.  (Contributed by Petr Viktorin
     in gh-93274(7).)

     The *note Py_TPFLAGS_MANAGED_DICT: 36e. and *note
     Py_TPFLAGS_MANAGED_WEAKREF: 55d. flags have been added.  This
     allows extensions classes to support object *note __dict__: 55e.
     and weakrefs with less bookkeeping, using less memory and with
     faster access.

   * API for performing calls using *note the vectorcall protocol: 555.
     was added to the *note Limited API: 556.:

        * *note PyObject_Vectorcall(): 55f.

        * *note PyObject_VectorcallMethod(): 560.

        * *note PY_VECTORCALL_ARGUMENTS_OFFSET: 561.

     This means that both the incoming and outgoing ends of the vector
     call protocol are now available in the *note Limited API: 556.
     (Contributed by Wenzel Jakob in gh-98586(8).)

   * Add two new public functions, *note PyEval_SetProfileAllThreads():
     562. and *note PyEval_SetTraceAllThreads(): 425, that allow to set
     tracing and profiling functions in all running threads in addition
     to the calling one.  (Contributed by Pablo Galindo in gh-93503(9).)

   * Add new function *note PyFunction_SetVectorcall(): 563. to the C
     API which sets the vectorcall field of a given *note
     PyFunctionObject: 564.  (Contributed by Andrew Frost in
     gh-92257(10).)

   * The C API now permits registering callbacks via *note
     PyDict_AddWatcher(): 565, *note PyDict_Watch(): 566. and related
     APIs to be called whenever a dictionary is modified.  This is
     intended for use by optimizing interpreters, JIT compilers, or
     debuggers.  (Contributed by Carl Meyer in gh-91052(11).)

   * Add *note PyType_AddWatcher(): 567. and *note PyType_Watch(): 568.
     API to register callbacks to receive notification on changes to a
     type.  (Contributed by Carl Meyer in gh-91051(12).)

   * Add *note PyCode_AddWatcher(): 569. and *note
     PyCode_ClearWatcher(): 56a. APIs to register callbacks to receive
     notification on creation and destruction of code objects.
     (Contributed by Itamar Oren in gh-91054(13).)

   * Add *note PyFrame_GetVar(): 56b. and *note PyFrame_GetVarString():
     56c. functions to get a frame variable by its name.  (Contributed
     by Victor Stinner in gh-91248(14).)

   * Add *note PyErr_GetRaisedException(): 3f7. and *note
     PyErr_SetRaisedException(): 3fa. for saving and restoring the
     current exception.  These functions return and accept a single
     exception object, rather than the triple arguments of the
     now-deprecated *note PyErr_Fetch(): 3f6. and *note PyErr_Restore():
     3f9.  This is less error prone and a bit more efficient.
     (Contributed by Mark Shannon in gh-101578(15).)

   * Add ‘_PyErr_ChainExceptions1’, which takes an exception instance,
     to replace the legacy-API ‘_PyErr_ChainExceptions’, which is now
     deprecated.  (Contributed by Mark Shannon in gh-101578(16).)

   * Add *note PyException_GetArgs(): 56d. and *note
     PyException_SetArgs(): 56e. as convenience functions for retrieving
     and modifying the *note args: 56f. passed to the exception’s
     constructor.  (Contributed by Mark Shannon in gh-101578(17).)

   * Add *note PyErr_DisplayException(): 405, which takes an exception
     instance, to replace the legacy-api ‘PyErr_Display()’.
     (Contributed by Irit Katriel in gh-102755(18)).

   * PEP 683(19): Introduce 'Immortal Objects', which allows objects to
     bypass reference counts, and related changes to the C-API:

        - 
          ‘_Py_IMMORTAL_REFCNT’: The reference count that defines an object

               as immortal.

        - ‘_Py_IsImmortal’ Checks if an object has the immortal
          reference count.

        - 
          ‘PyObject_HEAD_INIT’ This will now initialize reference count to

               ‘_Py_IMMORTAL_REFCNT’ when used with ‘Py_BUILD_CORE’.

        - 
          ‘SSTATE_INTERNED_IMMORTAL’ An identifier for interned unicode objects

               that are immortal.

        - 
          ‘SSTATE_INTERNED_IMMORTAL_STATIC’ An identifier for interned unicode

               objects that are immortal and static

        - 
          ‘sys.getunicodeinternedsize’ This returns the total number of unicode

               objects that have been interned.  This is now needed for
               ‘refleak.py’ to correctly track reference counts and
               allocated blocks

     (Contributed by Eddie Elizondo in gh-84436(20).)

   * PEP 684(21): Add the new *note Py_NewInterpreterFromConfig(): 45f.
     function and *note PyInterpreterConfig: 570, which may be used to
     create sub-interpreters with their own GILs.  (See *note PEP 684; A
     Per-Interpreter GIL: 43f. for more info.)  (Contributed by Eric
     Snow in gh-104110(22).)

   * In the limited C API version 3.12, *note Py_INCREF(): 571. and
     *note Py_DECREF(): 572. functions are now implemented as opaque
     function calls to hide implementation details.  (Contributed by
     Victor Stinner in gh-105387(23).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0697/

   (2) https://peps.python.org/pep-0523/

   (3) https://github.com/python/cpython/issues/101101

   (4) https://peps.python.org/pep-0697/

   (5) https://github.com/python/cpython/issues/103509

   (6) https://github.com/python/cpython/issues/93012

   (7) https://github.com/python/cpython/issues/93274

   (8) https://github.com/python/cpython/issues/98586

   (9) https://github.com/python/cpython/issues/93503

   (10) https://github.com/python/cpython/issues/92257

   (11) https://github.com/python/cpython/issues/91052

   (12) https://github.com/python/cpython/issues/91051

   (13) https://github.com/python/cpython/issues/91054

   (14) https://github.com/python/cpython/issues/91248

   (15) https://github.com/python/cpython/issues/101578

   (16) https://github.com/python/cpython/issues/101578

   (17) https://github.com/python/cpython/issues/101578

   (18) https://github.com/python/cpython/issues/102755

   (19) https://peps.python.org/pep-0683/

   (20) https://github.com/python/cpython/issues/84436

   (21) https://peps.python.org/pep-0684/

   (22) https://github.com/python/cpython/issues/104110

   (23) https://github.com/python/cpython/issues/105387


File: python.info,  Node: Porting to Python 3 12<2>,  Next: Deprecated<2>,  Prev: New Features<4>,  Up: C API Changes<2>

1.2.14.2 Porting to Python 3.12
...............................

   * Legacy Unicode APIs based on ‘Py_UNICODE*’ representation has been
     removed.  Please migrate to APIs based on UTF-8 or ‘wchar_t*’.

   * Argument parsing functions like *note PyArg_ParseTuple(): 574.
     doesn’t support ‘Py_UNICODE*’ based format (e.g.  ‘u’, ‘Z’)
     anymore.  Please migrate to other formats for Unicode like ‘s’,
     ‘z’, ‘es’, and ‘U’.

   * ‘tp_weaklist’ for all static builtin types is always ‘NULL’.  This
     is an internal-only field on ‘PyTypeObject’ but we’re pointing out
     the change in case someone happens to be accessing the field
     directly anyway.  To avoid breakage, consider using the existing
     public C-API instead, or, if necessary, the (internal-only)
     ‘_PyObject_GET_WEAKREFS_LISTPTR()’ macro.

   * This internal-only *note PyTypeObject.tp_subclasses: 575. may now
     not be a valid object pointer.  Its type was changed to void* to
     reflect this.  We mention this in case someone happens to be
     accessing the internal-only field directly.

     To get a list of subclasses, call the Python method *note
     __subclasses__(): 576. (using *note PyObject_CallMethod(): 3a2, for
     example).

   * Add support of more formatting options (left aligning, octals,
     uppercase hexadecimals, ‘intmax_t’, ‘ptrdiff_t’, ‘wchar_t’ C
     strings, variable width and precision) in *note
     PyUnicode_FromFormat(): 38d. and *note PyUnicode_FromFormatV():
     577.  (Contributed by Serhiy Storchaka in gh-98836(1).)

   * An unrecognized format character in *note PyUnicode_FromFormat():
     38d. and *note PyUnicode_FromFormatV(): 577. now sets a *note
     SystemError: 578.  In previous versions it caused all the rest of
     the format string to be copied as-is to the result string, and any
     extra arguments discarded.  (Contributed by Serhiy Storchaka in
     gh-95781(2).)

   * Fix wrong sign placement in *note PyUnicode_FromFormat(): 38d. and
     *note PyUnicode_FromFormatV(): 577.  (Contributed by Philip Georgi
     in gh-95504(3).)

   * Extension classes wanting to add a *note __dict__: 55e. or weak
     reference slot should use *note Py_TPFLAGS_MANAGED_DICT: 36e. and
     *note Py_TPFLAGS_MANAGED_WEAKREF: 55d. instead of ‘tp_dictoffset’
     and ‘tp_weaklistoffset’, respectively.  The use of ‘tp_dictoffset’
     and ‘tp_weaklistoffset’ is still supported, but does not fully
     support multiple inheritance (gh-95589(4)), and performance may be
     worse.  Classes declaring ‘Py_TPFLAGS_MANAGED_DICT’ must call
     ‘_PyObject_VisitManagedDict()’ and ‘_PyObject_ClearManagedDict()’
     to traverse and clear their instance’s dictionaries.  To clear
     weakrefs, call *note PyObject_ClearWeakRefs(): 579, as before.

   * The *note PyUnicode_FSDecoder(): 57a. function no longer accepts
     bytes-like paths, like *note bytearray: 2ea. and *note memoryview:
     2eb. types: only the exact *note bytes: 1c2. type is accepted for
     bytes strings.  (Contributed by Victor Stinner in gh-98393(5).)

   * The *note Py_CLEAR: 57b, *note Py_SETREF: 57c. and *note
     Py_XSETREF: 57d. macros now only evaluate their arguments once.  If
     an argument has side effects, these side effects are no longer
     duplicated.  (Contributed by Victor Stinner in gh-98724(6).)

   * The interpreter’s error indicator is now always normalized.  This
     means that *note PyErr_SetObject(): 57e, *note PyErr_SetString():
     57f. and the other functions that set the error indicator now
     normalize the exception before storing it.  (Contributed by Mark
     Shannon in gh-101578(7).)

   * ‘_Py_RefTotal’ is no longer authoritative and only kept around for
     ABI compatibility.  Note that it is an internal global and only
     available on debug builds.  If you happen to be using it then
     you’ll need to start using ‘_Py_GetGlobalRefTotal()’.

   * The following functions now select an appropriate metaclass for the
     newly created type:

        * *note PyType_FromSpec(): 580.

        * *note PyType_FromSpecWithBases(): 581.

        * *note PyType_FromModuleAndSpec(): 554.

     Creating classes whose metaclass overrides *note tp_new: 582. is
     deprecated, and in Python 3.14+ it will be disallowed.  Note that
     these functions ignore ‘tp_new’ of the metaclass, possibly allowing
     incomplete initialization.

     Note that *note PyType_FromMetaclass(): 553. (added in Python 3.12)
     already disallows creating classes whose metaclass overrides
     ‘tp_new’ (*note __new__(): 583. in Python).

     Since ‘tp_new’ overrides almost everything ‘PyType_From*’ functions
     do, the two are incompatible with each other.  The existing
     behavior – ignoring the metaclass for several steps of type
     creation – is unsafe in general, since (meta)classes assume that
     ‘tp_new’ was called.  There is no simple general workaround.  One
     of the following may work for you:

        - If you control the metaclass, avoid using ‘tp_new’ in it:

             - If initialization can be skipped, it can be done in *note
               tp_init: 584. instead.

             - If the metaclass doesn’t need to be instantiated from
               Python, set its ‘tp_new’ to ‘NULL’ using the *note
               Py_TPFLAGS_DISALLOW_INSTANTIATION: 585. flag.  This makes
               it acceptable for ‘PyType_From*’ functions.

        - Avoid ‘PyType_From*’ functions: if you don’t need C-specific
          features (slots or setting the instance size), create types by
          *note calling: 586. the metaclass.

        - If you 'know' the ‘tp_new’ can be skipped safely, filter the
          deprecation warning out using *note warnings.catch_warnings():
          587. from Python.

   * *note PyOS_InputHook: 588. and *note PyOS_ReadlineFunctionPointer:
     589. are no longer called in *note subinterpreters: 58a.  This is
     because clients generally rely on process-wide global state (since
     these callbacks have no way of recovering extension module state).

     This also avoids situations where extensions may find themselves
     running in a subinterpreter that they don’t support (or haven’t yet
     been loaded in).  See gh-104668(8) for more info.

   * *note PyLongObject: 58b. has had its internals changed for better
     performance.  Although the internals of ‘PyLongObject’ are private,
     they are used by some extension modules.  The internal fields
     should no longer be accessed directly, instead the API functions
     beginning ‘PyLong_...’ should be used instead.  Two new 'unstable'
     API functions are provided for efficient access to the value of
     ‘PyLongObject’s which fit into a single machine word:

        * *note PyUnstable_Long_IsCompact(): 58c.

        * *note PyUnstable_Long_CompactValue(): 58d.

   * Custom allocators, set via *note PyMem_SetAllocator(): 58e, are now
     required to be thread-safe, regardless of memory domain.
     Allocators that don’t have their own state, including “hooks”, are
     not affected.  If your custom allocator is not already thread-safe
     and you need guidance then please create a new GitHub issue and CC
     ‘@ericsnowcurrently’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98836

   (2) https://github.com/python/cpython/issues/95781

   (3) https://github.com/python/cpython/issues/95504

   (4) https://github.com/python/cpython/issues/95589

   (5) https://github.com/python/cpython/issues/98393

   (6) https://github.com/python/cpython/issues/98724

   (7) https://github.com/python/cpython/issues/101578

   (8) https://github.com/python/cpython/issues/104668


File: python.info,  Node: Deprecated<2>,  Next: Removed<2>,  Prev: Porting to Python 3 12<2>,  Up: C API Changes<2>

1.2.14.3 Deprecated
...................

   * In accordance with PEP 699(1), the ‘ma_version_tag’ field in *note
     PyDictObject: 3c4. is deprecated for extension modules.  Accessing
     this field will generate a compiler warning at compile time.  This
     field will be removed in Python 3.14.  (Contributed by Ramvikrams
     and Kumar Aditya in gh-101193(2).  PEP by Ken Jin.)

   * Deprecate global configuration variable:

        * *note Py_DebugFlag: 3c9.: use *note PyConfig.parser_debug:
          3ca.

        * *note Py_VerboseFlag: 3cb.: use *note PyConfig.verbose: 3cc.

        * *note Py_QuietFlag: 3cd.: use *note PyConfig.quiet: 3ce.

        * *note Py_InteractiveFlag: 3cf.: use *note
          PyConfig.interactive: 3d0.

        * *note Py_InspectFlag: 3d1.: use *note PyConfig.inspect: 3d2.

        * *note Py_OptimizeFlag: 3d3.: use *note
          PyConfig.optimization_level: 3d4.

        * *note Py_NoSiteFlag: 3d5.: use *note PyConfig.site_import:
          3d6.

        * *note Py_BytesWarningFlag: 3d7.: use *note
          PyConfig.bytes_warning: 3d8.

        * *note Py_FrozenFlag: 3d9.: use *note
          PyConfig.pathconfig_warnings: 3da.

        * *note Py_IgnoreEnvironmentFlag: 3db.: use *note
          PyConfig.use_environment: 3dc.

        * *note Py_DontWriteBytecodeFlag: 3dd.: use *note
          PyConfig.write_bytecode: 3de.

        * *note Py_NoUserSiteDirectory: 3df.: use *note
          PyConfig.user_site_directory: 3e0.

        * *note Py_UnbufferedStdioFlag: 3e1.: use *note
          PyConfig.buffered_stdio: 3e2.

        * *note Py_HashRandomizationFlag: 3e3.: use *note
          PyConfig.use_hash_seed: 3e4. and *note PyConfig.hash_seed:
          3e5.

        * *note Py_IsolatedFlag: 3e6.: use *note PyConfig.isolated: 3e7.

        * *note Py_LegacyWindowsFSEncodingFlag: 3e8.: use *note
          PyPreConfig.legacy_windows_fs_encoding: 3e9.

        * *note Py_LegacyWindowsStdioFlag: 3ea.: use *note
          PyConfig.legacy_windows_stdio: 3a7.

        * ‘Py_FileSystemDefaultEncoding’: use *note
          PyConfig.filesystem_encoding: 3eb.

        * ‘Py_HasFileSystemDefaultEncoding’: use *note
          PyConfig.filesystem_encoding: 3eb.

        * ‘Py_FileSystemDefaultEncodeErrors’: use *note
          PyConfig.filesystem_errors: 3ec.

        * ‘Py_UTF8Mode’: use *note PyPreConfig.utf8_mode: 3ed. (see
          *note Py_PreInitialize(): 3ee.)

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.  (Contributed by Victor Stinner in
     gh-77782(3).)

   * Creating *note immutable types: 3c5. with mutable bases is
     deprecated and will be disabled in Python 3.14.  (gh-95388(4))

   * The ‘structmember.h’ header is deprecated, though it continues to
     be available and there are no plans to remove it.

     Its contents are now available just by including ‘Python.h’, with a
     ‘Py’ prefix added if it was missing:

        - *note PyMemberDef: 552, *note PyMember_GetOne(): 590. and
          *note PyMember_SetOne(): 591.

        - Type macros like *note Py_T_INT: 592, *note Py_T_DOUBLE: 593,
          etc.  (previously ‘T_INT’, ‘T_DOUBLE’, etc.)

        - The flags *note Py_READONLY: 594. (previously ‘READONLY’) and
          *note Py_AUDIT_READ: 595. (previously all uppercase)

     Several items are not exposed from ‘Python.h’:

        - *note T_OBJECT: 596. (use *note Py_T_OBJECT_EX: 597.)

        - *note T_NONE: 598. (previously undocumented, and pretty
          quirky)

        - The macro ‘WRITE_RESTRICTED’ which does nothing.

        - The macros ‘RESTRICTED’ and ‘READ_RESTRICTED’, equivalents of
          *note Py_AUDIT_READ: 595.

        - In some configurations, ‘<stddef.h>’ is not included from
          ‘Python.h’.  It should be included manually when using
          ‘offsetof()’.

     The deprecated header continues to provide its original contents
     under the original names.  Your old code can stay unchanged, unless
     the extra include and non-namespaced macros bother you greatly.

     (Contributed in gh-47146(5) by Petr Viktorin, based on earlier work
     by Alexander Belopolsky and Matthias Braun.)

   * *note PyErr_Fetch(): 3f6. and *note PyErr_Restore(): 3f9. are
     deprecated.  Use *note PyErr_GetRaisedException(): 3f7. and *note
     PyErr_SetRaisedException(): 3fa. instead.  (Contributed by Mark
     Shannon in gh-101578(6).)

   * ‘PyErr_Display()’ is deprecated.  Use *note
     PyErr_DisplayException(): 405. instead.  (Contributed by Irit
     Katriel in gh-102755(7)).

   * ‘_PyErr_ChainExceptions’ is deprecated.  Use
     ‘_PyErr_ChainExceptions1’ instead.  (Contributed by Irit Katriel in
     gh-102192(8).)

   * Using *note PyType_FromSpec(): 580, *note
     PyType_FromSpecWithBases(): 581. or *note
     PyType_FromModuleAndSpec(): 554. to create a class whose metaclass
     overrides *note tp_new: 582. is deprecated.  Call the metaclass
     instead.

* Menu:

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<4>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<4>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<4>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<4>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0699/

   (2) https://github.com/python/cpython/issues/101193

   (3) https://github.com/python/cpython/issues/77782

   (4) https://github.com/python/cpython/issues/95388

   (5) https://github.com/python/cpython/issues/47146

   (6) https://github.com/python/cpython/issues/101578

   (7) https://github.com/python/cpython/issues/102755

   (8) https://github.com/python/cpython/issues/102192


File: python.info,  Node: Pending Removal in Python 3 14<4>,  Next: Pending Removal in Python 3 15<4>,  Up: Deprecated<2>

1.2.14.4 Pending Removal in Python 3.14
.......................................

   * The ‘ma_version_tag’ field in *note PyDictObject: 3c4. for
     extension modules ( PEP 699(1); gh-101193(2)).

   * Creating *note immutable types: 3c5. with mutable bases
     (gh-95388(3)).

   * Functions to configure Python’s initialization, deprecated in
     Python 3.11:

        * ‘PySys_SetArgvEx()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘PySys_SetArgv()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘Py_SetProgramName()’: Set *note PyConfig.program_name: 3c7.
          instead.

        * ‘Py_SetPythonHome()’: Set *note PyConfig.home: 3be. instead.

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   * Global configuration variables:

        * *note Py_DebugFlag: 3c9.: Use *note PyConfig.parser_debug:
          3ca. instead.

        * *note Py_VerboseFlag: 3cb.: Use *note PyConfig.verbose: 3cc.
          instead.

        * *note Py_QuietFlag: 3cd.: Use *note PyConfig.quiet: 3ce.
          instead.

        * *note Py_InteractiveFlag: 3cf.: Use *note
          PyConfig.interactive: 3d0. instead.

        * *note Py_InspectFlag: 3d1.: Use *note PyConfig.inspect: 3d2.
          instead.

        * *note Py_OptimizeFlag: 3d3.: Use *note
          PyConfig.optimization_level: 3d4. instead.

        * *note Py_NoSiteFlag: 3d5.: Use *note PyConfig.site_import:
          3d6. instead.

        * *note Py_BytesWarningFlag: 3d7.: Use *note
          PyConfig.bytes_warning: 3d8. instead.

        * *note Py_FrozenFlag: 3d9.: Use *note
          PyConfig.pathconfig_warnings: 3da. instead.

        * *note Py_IgnoreEnvironmentFlag: 3db.: Use *note
          PyConfig.use_environment: 3dc. instead.

        * *note Py_DontWriteBytecodeFlag: 3dd.: Use *note
          PyConfig.write_bytecode: 3de. instead.

        * *note Py_NoUserSiteDirectory: 3df.: Use *note
          PyConfig.user_site_directory: 3e0. instead.

        * *note Py_UnbufferedStdioFlag: 3e1.: Use *note
          PyConfig.buffered_stdio: 3e2. instead.

        * *note Py_HashRandomizationFlag: 3e3.: Use *note
          PyConfig.use_hash_seed: 3e4. and *note PyConfig.hash_seed:
          3e5. instead.

        * *note Py_IsolatedFlag: 3e6.: Use *note PyConfig.isolated: 3e7.
          instead.

        * *note Py_LegacyWindowsFSEncodingFlag: 3e8.: Use *note
          PyPreConfig.legacy_windows_fs_encoding: 3e9. instead.

        * *note Py_LegacyWindowsStdioFlag: 3ea.: Use *note
          PyConfig.legacy_windows_stdio: 3a7. instead.

        * ‘Py_FileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_HasFileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_FileSystemDefaultEncodeErrors’: Use *note
          PyConfig.filesystem_errors: 3ec. instead.

        * ‘Py_UTF8Mode’: Use *note PyPreConfig.utf8_mode: 3ed. instead.
          (see *note Py_PreInitialize(): 3ee.)

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0699/

   (2) https://github.com/python/cpython/issues/101193

   (3) https://github.com/python/cpython/issues/95388


File: python.info,  Node: Pending Removal in Python 3 15<4>,  Next: Pending removal in Python 3 16<4>,  Prev: Pending Removal in Python 3 14<4>,  Up: Deprecated<2>

1.2.14.5 Pending Removal in Python 3.15
.......................................

   * The *note PyImport_ImportModuleNoBlock(): 3c0.: Use *note
     PyImport_ImportModule(): 3c1. instead.

   * *note PyWeakref_GetObject(): 37c. and *note PyWeakref_GET_OBJECT():
     3c2.: Use *note PyWeakref_GetRef(): 37b. instead.

   * *note Py_UNICODE: 3f0. type and the ‘Py_UNICODE_WIDE’ macro: Use
     ‘wchar_t’ instead.

   * Python initialization functions:

        * *note PySys_ResetWarnOptions(): 3b2.: Clear *note
          sys.warnoptions: 3b3. and ‘warnings.filters’ instead.

        * *note Py_GetExecPrefix(): 3b4.: Get *note
          sys.base_exec_prefix: 3f1. and *note sys.exec_prefix: 3b5.
          instead.

        * *note Py_GetPath(): 3b6.: Get *note sys.path: 3b7. instead.

        * *note Py_GetPrefix(): 3b8.: Get *note sys.base_prefix: 3f2.
          and *note sys.prefix: 3b9. instead.

        * *note Py_GetProgramFullPath(): 3ba.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetProgramName(): 3bc.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetPythonHome(): 3bd.: Get *note PyConfig.home: 3be.
          or the *note PYTHONHOME: 3bf. environment variable instead.


File: python.info,  Node: Pending removal in Python 3 16<4>,  Next: Pending Removal in Future Versions<4>,  Prev: Pending Removal in Python 3 15<4>,  Up: Deprecated<2>

1.2.14.6 Pending removal in Python 3.16
.......................................

   * The bundled copy of ‘libmpdec’.


File: python.info,  Node: Pending Removal in Future Versions<4>,  Prev: Pending removal in Python 3 16<4>,  Up: Deprecated<2>

1.2.14.7 Pending Removal in Future Versions
...........................................

The following APIs are deprecated and will be removed, although there is
currently no date scheduled for their removal.

   * *note Py_TPFLAGS_HAVE_FINALIZE: 3f5.: Unneeded since Python 3.8.

   * *note PyErr_Fetch(): 3f6.: Use *note PyErr_GetRaisedException():
     3f7. instead.

   * *note PyErr_NormalizeException(): 3f8.: Use *note
     PyErr_GetRaisedException(): 3f7. instead.

   * *note PyErr_Restore(): 3f9.: Use *note PyErr_SetRaisedException():
     3fa. instead.

   * *note PyModule_GetFilename(): 3fb.: Use *note
     PyModule_GetFilenameObject(): 3fc. instead.

   * *note PyOS_AfterFork(): 3fd.: Use *note PyOS_AfterFork_Child():
     3fe. instead.

   * *note PySlice_GetIndicesEx(): 3ff.: Use *note PySlice_Unpack():
     400. and *note PySlice_AdjustIndices(): 401. instead.

   * ‘PyUnicode_AsDecodedObject()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsDecodedUnicode()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsEncodedObject()’: Use *note PyCodec_Encode(): 403.
     instead.

   * ‘PyUnicode_AsEncodedUnicode()’: Use *note PyCodec_Encode(): 403.
     instead.

   * *note PyUnicode_READY(): 404.: Unneeded since Python 3.12

   * ‘PyErr_Display()’: Use *note PyErr_DisplayException(): 405.
     instead.

   * ‘_PyErr_ChainExceptions()’: Use ‘_PyErr_ChainExceptions1()’
     instead.

   * ‘PyBytesObject.ob_shash’ member: call *note PyObject_Hash(): 406.
     instead.

   * ‘PyDictObject.ma_version_tag’ member.

   * Thread Local Storage (TLS) API:

        * *note PyThread_create_key(): 407.: Use *note
          PyThread_tss_alloc(): 408. instead.

        * *note PyThread_delete_key(): 409.: Use *note
          PyThread_tss_free(): 40a. instead.

        * *note PyThread_set_key_value(): 40b.: Use *note
          PyThread_tss_set(): 40c. instead.

        * *note PyThread_get_key_value(): 40d.: Use *note
          PyThread_tss_get(): 40e. instead.

        * *note PyThread_delete_key_value(): 40f.: Use *note
          PyThread_tss_delete(): 410. instead.

        * *note PyThread_ReInitTLS(): 411.: Unneeded since Python 3.7.


File: python.info,  Node: Removed<2>,  Prev: Deprecated<2>,  Up: C API Changes<2>

1.2.14.8 Removed
................

   * Remove the ‘token.h’ header file.  There was never any public
     tokenizer C API. The ‘token.h’ header file was only designed to be
     used by Python internals.  (Contributed by Victor Stinner in
     gh-92651(1).)

   * Legacy Unicode APIs have been removed.  See PEP 623(2) for detail.

        * ‘PyUnicode_WCHAR_KIND’

        * ‘PyUnicode_AS_UNICODE()’

        * ‘PyUnicode_AsUnicode()’

        * ‘PyUnicode_AsUnicodeAndSize()’

        * ‘PyUnicode_AS_DATA()’

        * ‘PyUnicode_FromUnicode()’

        * ‘PyUnicode_GET_SIZE()’

        * ‘PyUnicode_GetSize()’

        * ‘PyUnicode_GET_DATA_SIZE()’

   * Remove the ‘PyUnicode_InternImmortal()’ function macro.
     (Contributed by Victor Stinner in gh-85858(3).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92651

   (2) https://peps.python.org/pep-0623/

   (3) https://github.com/python/cpython/issues/85858


File: python.info,  Node: What’s New In Python 3 11,  Next: What’s New In Python 3 10,  Prev: What’s New In Python 3 12,  Up: What’s New in Python

1.3 What’s New In Python 3.11
=============================


Editor: Pablo Galindo Salgado

This article explains the new features in Python 3.11, compared to 3.10.
Python 3.11 was released on October 24, 2022.  For full details, see the
*note changelog: 13c.

* Menu:

* Summary – Release highlights: Summary – Release highlights<2>.
* New Features: New Features<5>.
* New Features Related to Type Hints: New Features Related to Type Hints<2>.
* Other Language Changes: Other Language Changes<3>.
* Other CPython Implementation Changes::
* New Modules: New Modules<3>.
* Improved Modules: Improved Modules<3>.
* Optimizations: Optimizations<3>.
* Faster CPython::
* CPython bytecode changes: CPython bytecode changes<2>.
* Deprecated: Deprecated<3>.
* Pending Removal in Python 3.12: Pending Removal in Python 3 12.
* Removed: Removed<3>.
* Porting to Python 3.11: Porting to Python 3 11.
* Build Changes: Build Changes<3>.
* C API Changes: C API Changes<3>.
* Notable changes in 3.11.4: Notable changes in 3 11 4.
* Notable changes in 3.11.5: Notable changes in 3 11 5.


File: python.info,  Node: Summary – Release highlights<2>,  Next: New Features<5>,  Up: What’s New In Python 3 11

1.3.1 Summary – Release highlights
----------------------------------

   * Python 3.11 is between 10-60% faster than Python 3.10.  On average,
     we measured a 1.25x speedup on the standard benchmark suite.  See
     *note Faster CPython: 5a3. for details.

New syntax features:

   * *note PEP 654; Exception Groups and except*: 5a4.

New built-in features:

   * *note PEP 678; Exceptions can be enriched with notes: 5a5.

New standard library modules:

   * PEP 680(1): *note tomllib: fc. — Support for parsing TOML(2) in the
     Standard Library

Interpreter improvements:

   * *note PEP 657; Fine-grained error locations in tracebacks: 5a6.

   * New *note -P: 5a7. command line option and *note PYTHONSAFEPATH:
     5a8. environment variable to *note disable automatically prepending
     potentially unsafe paths: 5a9. to *note sys.path: 3b7.

New typing features:

   * *note PEP 646; Variadic generics: 5aa.

   * *note PEP 655; Marking individual TypedDict items as required or
     not-required: 5ab.

   * *note PEP 673; Self type: 5ac.

   * *note PEP 675; Arbitrary literal string type: 5ad.

   * *note PEP 681; Data class transforms: 5ae.

Important deprecations, removals and restrictions:

   * PEP 594(3): *note Many legacy standard library modules have been
     deprecated: 5af. and will be removed in Python 3.13

   * PEP 624(4): *note Py_UNICODE encoder APIs have been removed: 5b0.

   * PEP 670(5): *note Macros converted to static inline functions: 5b1.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0680/

   (2) https://toml.io/

   (3) https://peps.python.org/pep-0594/

   (4) https://peps.python.org/pep-0624/

   (5) https://peps.python.org/pep-0670/


File: python.info,  Node: New Features<5>,  Next: New Features Related to Type Hints<2>,  Prev: Summary – Release highlights<2>,  Up: What’s New In Python 3 11

1.3.2 New Features
------------------

* Menu:

* PEP 657; Fine-grained error locations in tracebacks: PEP 657 Fine-grained error locations in tracebacks.
* PEP 654; Exception Groups and except*: PEP 654 Exception Groups and except*.
* PEP 678; Exceptions can be enriched with notes: PEP 678 Exceptions can be enriched with notes.
* Windows py.exe launcher improvements: Windows py exe launcher improvements.


File: python.info,  Node: PEP 657 Fine-grained error locations in tracebacks,  Next: PEP 654 Exception Groups and except*,  Up: New Features<5>

1.3.2.1 PEP 657: Fine-grained error locations in tracebacks
...........................................................

When printing tracebacks, the interpreter will now point to the exact
expression that caused the error, instead of just the line.  For
example:

     Traceback (most recent call last):
       File "distance.py", line 11, in <module>
         print(manhattan_distance(p1, p2))
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
       File "distance.py", line 6, in manhattan_distance
         return abs(point_1.x - point_2.x) + abs(point_1.y - point_2.y)
                                ^^^^^^^^^
     AttributeError: 'NoneType' object has no attribute 'x'

Previous versions of the interpreter would point to just the line,
making it ambiguous which object was ‘None’.  These enhanced errors can
also be helpful when dealing with deeply nested *note dict: 256. objects
and multiple function calls:

     Traceback (most recent call last):
       File "query.py", line 37, in <module>
         magic_arithmetic('foo')
       File "query.py", line 18, in magic_arithmetic
         return add_counts(x) / 25
                ^^^^^^^^^^^^^
       File "query.py", line 24, in add_counts
         return 25 + query_user(user1) + query_user(user2)
                     ^^^^^^^^^^^^^^^^^
       File "query.py", line 32, in query_user
         return 1 + query_count(db, response['a']['b']['c']['user'], retry=True)
                                    ~~~~~~~~~~~~~~~~~~^^^^^
     TypeError: 'NoneType' object is not subscriptable

As well as complex arithmetic expressions:

     Traceback (most recent call last):
       File "calculation.py", line 54, in <module>
         result = (x / y / z) * (a / b / c)
                   ~~~~~~^~~
     ZeroDivisionError: division by zero

Additionally, the information used by the enhanced traceback feature is
made available via a general API, that can be used to correlate *note
bytecode: 187. *note instructions: 5b5. with source code location.  This
information can be retrieved using:

   - The *note codeobject.co_positions(): 5b6. method in Python.

   - The *note PyCode_Addr2Location(): 5b7. function in the C API.

See PEP 657(1) for more details.  (Contributed by Pablo Galindo, Batuhan
Taskaya and Ammar Askar in bpo-43950(2).)

     Note: This feature requires storing column positions in *note Code
     Objects: 5b8, which may result in a small increase in interpreter
     memory usage and disk usage for compiled Python files.  To avoid
     storing the extra information and deactivate printing the extra
     traceback information, use the *note -X no_debug_ranges: 176.
     command line option or the *note PYTHONNODEBUGRANGES: 5b9.
     environment variable.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0657/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43950


File: python.info,  Node: PEP 654 Exception Groups and except*,  Next: PEP 678 Exceptions can be enriched with notes,  Prev: PEP 657 Fine-grained error locations in tracebacks,  Up: New Features<5>

1.3.2.2 PEP 654: Exception Groups and ‘except*’
...............................................

PEP 654(1) introduces language features that enable a program to raise
and handle multiple unrelated exceptions simultaneously.  The builtin
types *note ExceptionGroup: 1b6. and *note BaseExceptionGroup: 25f. make
it possible to group exceptions and raise them together, and the new
*note except*: 5bb. syntax generalizes *note except: 18b. to match
subgroups of exception groups.

See PEP 654(2) for more details.

(Contributed by Irit Katriel in bpo-45292(3).  PEP written by Irit
Katriel, Yury Selivanov and Guido van Rossum.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0654/

   (2) https://peps.python.org/pep-0654/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45292


File: python.info,  Node: PEP 678 Exceptions can be enriched with notes,  Next: Windows py exe launcher improvements,  Prev: PEP 654 Exception Groups and except*,  Up: New Features<5>

1.3.2.3 PEP 678: Exceptions can be enriched with notes
......................................................

The *note add_note(): 5bd. method is added to *note BaseException: 5be.
It can be used to enrich exceptions with context information that is not
available at the time when the exception is raised.  The added notes
appear in the default traceback.

See PEP 678(1) for more details.

(Contributed by Irit Katriel in bpo-45607(2).  PEP written by Zac
Hatfield-Dodds.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0678/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45607


File: python.info,  Node: Windows py exe launcher improvements,  Prev: PEP 678 Exceptions can be enriched with notes,  Up: New Features<5>

1.3.2.4 Windows ‘py.exe’ launcher improvements
..............................................

The copy of the *note Python Launcher for Windows: 5c1. included with
Python 3.11 has been significantly updated.  It now supports company/tag
syntax as defined in PEP 514(1) using the ‘-V:<COMPANY>/<TAG>’ argument
instead of the limited ‘-<MAJOR>.<MINOR>’.  This allows launching
distributions other than ‘PythonCore’, the one hosted on python.org(2).

When using ‘-V:’ selectors, either company or tag can be omitted, but
all installs will be searched.  For example, ‘-V:OtherPython/’ will
select the “best” tag registered for ‘OtherPython’, while ‘-V:3.11’ or
‘-V:/3.11’ will select the “best” distribution with tag ‘3.11’.

When using the legacy ‘-<MAJOR>’, ‘-<MAJOR>.<MINOR>’,
‘-<MAJOR>-<BITNESS>’ or ‘-<MAJOR>.<MINOR>-<BITNESS>’ arguments, all
existing behaviour should be preserved from past versions, and only
releases from ‘PythonCore’ will be selected.  However, the ‘-64’ suffix
now implies “not 32-bit” (not necessarily x86-64), as there are multiple
supported 64-bit platforms.  32-bit runtimes are detected by checking
the runtime’s tag for a ‘-32’ suffix.  All releases of Python since 3.5
have included this in their 32-bit builds.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0514/

   (2) https://www.python.org


File: python.info,  Node: New Features Related to Type Hints<2>,  Next: Other Language Changes<3>,  Prev: New Features<5>,  Up: What’s New In Python 3 11

1.3.3 New Features Related to Type Hints
----------------------------------------

This section covers major changes affecting PEP 484(1) type hints and
the *note typing: 104. module.

* Menu:

* PEP 646; Variadic generics: PEP 646 Variadic generics.
* PEP 655; Marking individual TypedDict items as required or not-required: PEP 655 Marking individual TypedDict items as required or not-required.
* PEP 673; Self type: PEP 673 Self type.
* PEP 675; Arbitrary literal string type: PEP 675 Arbitrary literal string type.
* PEP 681; Data class transforms: PEP 681 Data class transforms.
* PEP 563 may not be the future::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: PEP 646 Variadic generics,  Next: PEP 655 Marking individual TypedDict items as required or not-required,  Up: New Features Related to Type Hints<2>

1.3.3.1 PEP 646: Variadic generics
..................................

PEP 484(1) previously introduced *note TypeVar: 15d, enabling creation
of generics parameterised with a single type.  PEP 646(2) adds *note
TypeVarTuple: 15f, enabling parameterisation with an 'arbitrary' number
of types.  In other words, a ‘TypeVarTuple’ is a 'variadic' type
variable, enabling 'variadic' generics.

This enables a wide variety of use cases.  In particular, it allows the
type of array-like structures in numerical computing libraries such as
NumPy and TensorFlow to be parameterised with the array 'shape'.  Static
type checkers will now be able to catch shape-related bugs in code that
uses these libraries.

See PEP 646(3) for more details.

(Contributed by Matthew Rahtz in bpo-43224(4), with contributions by
Serhiy Storchaka and Jelle Zijlstra.  PEP written by Mark Mendoza,
Matthew Rahtz, Pradeep Kumar Srinivasan, and Vincent Siles.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0646/

   (3) https://peps.python.org/pep-0646/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43224


File: python.info,  Node: PEP 655 Marking individual TypedDict items as required or not-required,  Next: PEP 673 Self type,  Prev: PEP 646 Variadic generics,  Up: New Features Related to Type Hints<2>

1.3.3.2 PEP 655: Marking individual ‘TypedDict’ items as required or not-required
.................................................................................

*note Required: 5c7. and *note NotRequired: 5c8. provide a
straightforward way to mark whether individual items in a *note
TypedDict: 162. must be present.  Previously, this was only possible
using inheritance.

All fields are still required by default, unless the 'total' parameter
is set to ‘False’, in which case all fields are still not-required by
default.  For example, the following specifies a ‘TypedDict’ with one
required and one not-required key:

     class Movie(TypedDict):
        title: str
        year: NotRequired[int]

     m1: Movie = {"title": "Black Panther", "year": 2018}  # OK
     m2: Movie = {"title": "Star Wars"}  # OK (year is not required)
     m3: Movie = {"year": 2022}  # ERROR (missing required field title)

The following definition is equivalent:

     class Movie(TypedDict, total=False):
        title: Required[str]
        year: int

See PEP 655(1) for more details.

(Contributed by David Foster and Jelle Zijlstra in bpo-47087(2).  PEP
written by David Foster.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0655/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47087


File: python.info,  Node: PEP 673 Self type,  Next: PEP 675 Arbitrary literal string type,  Prev: PEP 655 Marking individual TypedDict items as required or not-required,  Up: New Features Related to Type Hints<2>

1.3.3.3 PEP 673: ‘Self’ type
............................

The new *note Self: 5ca. annotation provides a simple and intuitive way
to annotate methods that return an instance of their class.  This
behaves the same as the *note TypeVar: 15d.-based approach specified in
PEP 484(1), but is more concise and easier to follow.

Common use cases include alternative constructors provided as *note
classmethod: 166.s, and *note __enter__(): 5cb. methods that return
‘self’:

     class MyLock:
         def __enter__(self) -> Self:
             self.lock()
             return self

         ...

     class MyInt:
         @classmethod
         def fromhex(cls, s: str) -> Self:
             return cls(int(s, 16))

         ...

*note Self: 5ca. can also be used to annotate method parameters or
attributes of the same type as their enclosing class.

See PEP 673(2) for more details.

(Contributed by James Hilton-Balfe in bpo-46534(3).  PEP written by
Pradeep Kumar Srinivasan and James Hilton-Balfe.)

   ---------- Footnotes ----------

   (1) 
https://peps.python.org/pep-0484/#annotating-instance-and-class-methods

   (2) https://peps.python.org/pep-0673/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46534


File: python.info,  Node: PEP 675 Arbitrary literal string type,  Next: PEP 681 Data class transforms,  Prev: PEP 673 Self type,  Up: New Features Related to Type Hints<2>

1.3.3.4 PEP 675: Arbitrary literal string type
..............................................

The new *note LiteralString: 5cd. annotation may be used to indicate
that a function parameter can be of any literal string type.  This
allows a function to accept arbitrary literal string types, as well as
strings created from other literal strings.  Type checkers can then
enforce that sensitive functions, such as those that execute SQL
statements or shell commands, are called only with static arguments,
providing protection against injection attacks.

For example, a SQL query function could be annotated as follows:

     def run_query(sql: LiteralString) -> ...
         ...

     def caller(
         arbitrary_string: str,
         query_string: LiteralString,
         table_name: LiteralString,
     ) -> None:
         run_query("SELECT * FROM students")       # ok
         run_query(query_string)                   # ok
         run_query("SELECT * FROM " + table_name)  # ok
         run_query(arbitrary_string)               # type checker error
         run_query(                                # type checker error
             f"SELECT * FROM students WHERE name = {arbitrary_string}"
         )

See PEP 675(1) for more details.

(Contributed by Jelle Zijlstra in bpo-47088(2).  PEP written by Pradeep
Kumar Srinivasan and Graham Bleaney.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0675/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47088


File: python.info,  Node: PEP 681 Data class transforms,  Next: PEP 563 may not be the future,  Prev: PEP 675 Arbitrary literal string type,  Up: New Features Related to Type Hints<2>

1.3.3.5 PEP 681: Data class transforms
......................................

*note dataclass_transform: 4d7. may be used to decorate a class,
metaclass, or a function that is itself a decorator.  The presence of
‘@dataclass_transform()’ tells a static type checker that the decorated
object performs runtime “magic” that transforms a class, giving it *note
dataclass: 1cb.-like behaviors.

For example:

     # The create_model decorator is defined by a library.
     @typing.dataclass_transform()
     def create_model(cls: Type[T]) -> Type[T]:
         cls.__init__ = ...
         cls.__eq__ = ...
         cls.__ne__ = ...
         return cls

     # The create_model decorator can now be used to create new model classes:
     @create_model
     class CustomerModel:
         id: int
         name: str

     c = CustomerModel(id=327, name="Eric Idle")

See PEP 681(1) for more details.

(Contributed by Jelle Zijlstra in gh-91860(2).  PEP written by Erik De
Bonte and Eric Traut.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0681/

   (2) https://github.com/python/cpython/issues/91860


File: python.info,  Node: PEP 563 may not be the future,  Prev: PEP 681 Data class transforms,  Up: New Features Related to Type Hints<2>

1.3.3.6 PEP 563 may not be the future
.....................................

PEP 563(1) Postponed Evaluation of Annotations (the ‘from __future__
import annotations’ *note future statement: 189.) that was originally
planned for release in Python 3.10 has been put on hold indefinitely.
See this message from the Steering Council(2) for more information.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0563/

   (2) 
https://mail.python.org/archives/list/python-dev@python.org/message/VIZEBX5EYMSYIJNDBF6DMUMZOCWHARSO/


File: python.info,  Node: Other Language Changes<3>,  Next: Other CPython Implementation Changes,  Prev: New Features Related to Type Hints<2>,  Up: What’s New In Python 3 11

1.3.4 Other Language Changes
----------------------------

   * Starred unpacking expressions can now be used in *note for: 2f2.
     statements.  (See bpo-46725(1) for more details.)

   * Asynchronous *note comprehensions: 5d3. are now allowed inside
     comprehensions in *note asynchronous functions: 5d4.  Outer
     comprehensions implicitly become asynchronous in this case.
     (Contributed by Serhiy Storchaka in bpo-33346(2).)

   * A *note TypeError: 2c3. is now raised instead of an *note
     AttributeError: 34e. in *note with: 5d5. statements and *note
     contextlib.ExitStack.enter_context(): 5d6. for objects that do not
     support the *note context manager: 5d7. protocol, and in *note
     async with: 5d8. statements and *note
     contextlib.AsyncExitStack.enter_async_context(): 5d9. for objects
     not supporting the *note asynchronous context manager: 5da.
     protocol.  (Contributed by Serhiy Storchaka in bpo-12022(3) and
     bpo-44471(4).)

   * Added *note object.__getstate__(): 5db, which provides the default
     implementation of the ‘__getstate__()’ method.  *note copy: 25.ing
     and *note pickle: a6.ing instances of subclasses of builtin types
     *note bytearray: 2ea, *note set: 5dc, *note frozenset: 5dd, *note
     collections.OrderedDict: 5de, *note collections.deque: 5df, *note
     weakref.WeakSet: 5e0, and *note datetime.tzinfo: 5e1. now copies
     and pickles instance attributes implemented as *note slots: 5e2.
     This change has an unintended side effect: It trips up a small
     minority of existing Python projects not expecting
     ‘object.__getstate__()’ to exist.  See the later comments on
     gh-70766(5) for discussions of what workarounds such code may need.
     (Contributed by Serhiy Storchaka in bpo-26579(6).)

   * Added a *note -P: 5a7. command line option and a *note
     PYTHONSAFEPATH: 5a8. environment variable, which disable the
     automatic prepending to *note sys.path: 3b7. of the script’s
     directory when running a script, or the current directory when
     using *note -c: 5e3. and *note -m: 5e4.  This ensures only stdlib
     and installed modules are picked up by *note import: 5e5, and
     avoids unintentionally or maliciously shadowing modules with those
     in a local (and typically user-writable) directory.  (Contributed
     by Victor Stinner in gh-57684(7).)

   * A ‘"z"’ option was added to the *note Format specification
     mini-language: 1e8. that coerces negative to positive zero after
     rounding to the format precision.  See PEP 682(8) for more details.
     (Contributed by John Belmonte in gh-90153(9).)

   * Bytes are no longer accepted on *note sys.path: 3b7.  Support broke
     sometime between Python 3.2 and 3.6, with no one noticing until
     after Python 3.10.0 was released.  In addition, bringing back
     support would be problematic due to interactions between *note -b:
     5e6. and *note sys.path_importer_cache: 5e7. when there is a
     mixture of *note str: 44f. and *note bytes: 1c2. keys.
     (Contributed by Thomas Grainger in gh-91181(10).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46725

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33346

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12022

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44471

   (5) https://github.com/python/cpython/issues/70766

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26579

   (7) https://github.com/python/cpython/issues/57684

   (8) https://peps.python.org/pep-0682/

   (9) https://github.com/python/cpython/issues/90153

   (10) https://github.com/python/cpython/issues/91181


File: python.info,  Node: Other CPython Implementation Changes,  Next: New Modules<3>,  Prev: Other Language Changes<3>,  Up: What’s New In Python 3 11

1.3.5 Other CPython Implementation Changes
------------------------------------------

   * The special methods *note __complex__(): 5ea. for *note complex:
     2f8. and *note __bytes__(): 5eb. for *note bytes: 1c2. are
     implemented to support the *note typing.SupportsComplex: 5ec. and
     *note typing.SupportsBytes: 5ed. protocols.  (Contributed by Mark
     Dickinson and Donghee Na in bpo-24234(1).)

   * ‘siphash13’ is added as a new internal hashing algorithm.  It has
     similar security properties as ‘siphash24’, but it is slightly
     faster for long inputs.  *note str: 44f, *note bytes: 1c2, and some
     other types now use it as the default algorithm for *note hash():
     5ee.  PEP 552(2) *note hash-based .pyc files: 5ef. now use
     ‘siphash13’ too.  (Contributed by Inada Naoki in bpo-29410(3).)

   * When an active exception is re-raised by a *note raise: 5f0.
     statement with no parameters, the traceback attached to this
     exception is now always ‘sys.exc_info()[1].__traceback__’.  This
     means that changes made to the traceback in the current *note
     except: 18b. clause are reflected in the re-raised exception.
     (Contributed by Irit Katriel in bpo-45711(4).)

   * The interpreter state’s representation of handled exceptions (aka
     ‘exc_info’ or ‘_PyErr_StackItem’) now only has the ‘exc_value’
     field; ‘exc_type’ and ‘exc_traceback’ have been removed, as they
     can be derived from ‘exc_value’.  (Contributed by Irit Katriel in
     bpo-45711(5).)

   * A new *note command line option: 5f1, ‘AppendPath’, has been added
     for the Windows installer.  It behaves similarly to ‘PrependPath’,
     but appends the install and scripts directories instead of
     prepending them.  (Contributed by Bastian Neuburger in
     bpo-44934(6).)

   * The *note PyConfig.module_search_paths_set: 5f2. field must now be
     set to ‘1’ for initialization to use *note
     PyConfig.module_search_paths: 3a5. to initialize *note sys.path:
     3b7.  Otherwise, initialization will recalculate the path and
     replace any values added to ‘module_search_paths’.

   * The output of the *note -help: 5f3. option now fits in 50 lines/80
     columns.  Information about *note Python environment variables:
     5f4. and *note -X: 176. options is now available using the
     respective *note -help-env: 5f5. and *note -help-xoptions: 5f6.
     flags, and with the new *note -help-all: 5f7.  (Contributed by Éric
     Araujo in bpo-46142(7).)

   * Converting between *note int: 257. and *note str: 44f. in bases
     other than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such
     as base 10 (decimal) now raises a *note ValueError: 202. if the
     number of digits in string form is above a limit to avoid potential
     denial of service attacks due to the algorithmic complexity.  This
     is a mitigation for CVE 2020-10735(8).  This limit can be
     configured or disabled by environment variable, command line flag,
     or *note sys: d9. APIs.  See the *note integer string conversion
     length limitation: 5f8. documentation.  The default limit is 4300
     digits in string form.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24234

   (2) https://peps.python.org/pep-0552/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29410

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44934

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46142

   (8) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: New Modules<3>,  Next: Improved Modules<3>,  Prev: Other CPython Implementation Changes,  Up: What’s New In Python 3 11

1.3.6 New Modules
-----------------

   * *note tomllib: fc.: For parsing TOML(1). See PEP 680(2) for more
     details.  (Contributed by Taneli Hukkinen in bpo-40059(3).)

   * *note wsgiref.types: 11c.: WSGI(4)-specific types for static type
     checking.  (Contributed by Sebastian Rittau in bpo-42012(5).)

   ---------- Footnotes ----------

   (1) https://toml.io/

   (2) https://peps.python.org/pep-0680/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40059

   (4) https://peps.python.org/pep-3333/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42012


File: python.info,  Node: Improved Modules<3>,  Next: Optimizations<3>,  Prev: New Modules<3>,  Up: What’s New In Python 3 11

1.3.7 Improved Modules
----------------------

* Menu:

* asyncio: asyncio<3>.
* contextlib::
* dataclasses::
* datetime::
* enum: enum<3>.
* fcntl::
* fractions: fractions<3>.
* functools::
* gzip: gzip<2>.
* hashlib: hashlib<2>.
* IDLE and idlelib::
* inspect: inspect<2>.
* locale: locale<3>.
* logging::
* math: math<3>.
* operator::
* os: os<3>.
* pathlib: pathlib<4>.
* re: re<3>.
* shutil: shutil<3>.
* socket::
* sqlite3: sqlite3<4>.
* string::
* sys: sys<4>.
* sysconfig::
* tempfile: tempfile<3>.
* threading: threading<2>.
* time: time<2>.
* tkinter: tkinter<3>.
* traceback: traceback<2>.
* typing: typing<4>.
* unicodedata: unicodedata<3>.
* unittest: unittest<4>.
* venv: venv<2>.
* warnings: warnings<2>.
* zipfile::


File: python.info,  Node: asyncio<3>,  Next: contextlib,  Up: Improved Modules<3>

1.3.7.1 asyncio
...............

   * Added the *note TaskGroup: 1b5. class, an *note asynchronous
     context manager: 5ff. holding a group of tasks that will wait for
     all of them upon exit.  For new code this is recommended over using
     *note create_task(): 1bf. and *note gather(): 600. directly.
     (Contributed by Yury Selivanov and others in gh-90908(1).)

   * Added *note timeout(): 601, an asynchronous context manager for
     setting a timeout on asynchronous operations.  For new code this is
     recommended over using *note wait_for(): 602. directly.
     (Contributed by Andrew Svetlov in gh-90927(2).)

   * Added the *note Runner: 603. class, which exposes the machinery
     used by *note run(): 47f.  (Contributed by Andrew Svetlov in
     gh-91218(3).)

   * Added the *note Barrier: 604. class to the synchronization
     primitives in the asyncio library, and the related *note
     BrokenBarrierError: 605. exception.  (Contributed by Yves Duprat
     and Andrew Svetlov in gh-87518(4).)

   * Added keyword argument 'all_errors' to *note
     asyncio.loop.create_connection(): 606. so that multiple connection
     errors can be raised as an *note ExceptionGroup: 1b6.

   * Added the *note asyncio.StreamWriter.start_tls(): 607. method for
     upgrading existing stream-based connections to TLS. (Contributed by
     Ian Good in bpo-34975(5).)

   * Added raw datagram socket functions to the event loop: *note
     sock_sendto(): 608, *note sock_recvfrom(): 609. and *note
     sock_recvfrom_into(): 60a.  These have implementations in *note
     SelectorEventLoop: 60b. and *note ProactorEventLoop: 60c.
     (Contributed by Alex Grönholm in bpo-46805(6).)

   * Added *note cancelling(): 1ba. and *note uncancel(): 1bb. methods
     to *note Task: 1be.  These are primarily intended for internal use,
     notably by *note TaskGroup: 1b5.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/90908

   (2) https://github.com/python/cpython/issues/90927

   (3) https://github.com/python/cpython/issues/91218

   (4) https://github.com/python/cpython/issues/87518

   (5) https://bugs.python.org/issue?@action=redirect&bpo=34975

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46805


File: python.info,  Node: contextlib,  Next: dataclasses,  Prev: asyncio<3>,  Up: Improved Modules<3>

1.3.7.2 contextlib
..................

   * Added non parallel-safe *note chdir(): 60f. context manager to
     change the current working directory and then restore it on exit.
     Simple wrapper around *note chdir(): 610.  (Contributed by Filipe
     Laíns in bpo-25625(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25625


File: python.info,  Node: dataclasses,  Next: datetime,  Prev: contextlib,  Up: Improved Modules<3>

1.3.7.3 dataclasses
...................

   * Change field default mutability check, allowing only defaults which
     are *note hashable: 613. instead of any object which is not an
     instance of *note dict: 256, *note list: 614. or *note set: 5dc.
     (Contributed by Eric V. Smith in bpo-44674(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44674


File: python.info,  Node: datetime,  Next: enum<3>,  Prev: dataclasses,  Up: Improved Modules<3>

1.3.7.4 datetime
................

   * Add *note datetime.UTC: 4f1, a convenience alias for *note
     datetime.timezone.utc: 617.  (Contributed by Kabir Kwatra in
     gh-91973(1).)

   * *note datetime.date.fromisoformat(): 618, *note
     datetime.time.fromisoformat(): 619. and *note
     datetime.datetime.fromisoformat(): 61a. can now be used to parse
     most ISO 8601 formats (barring only those that support fractional
     hours and minutes).  (Contributed by Paul Ganssle in gh-80010(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91973

   (2) https://github.com/python/cpython/issues/80010


File: python.info,  Node: enum<3>,  Next: fcntl,  Prev: datetime,  Up: Improved Modules<3>

1.3.7.5 enum
............

   * Renamed ‘EnumMeta’ to *note EnumType: 1e5. (‘EnumMeta’ kept as an
     alias).

   * Added *note StrEnum: 61d, with members that can be used as (and
     must be) strings.

   * Added *note ReprEnum: 61e, which only modifies the *note
     __repr__(): 61f. of members while returning their literal values
     (rather than names) for *note __str__(): 620. and *note
     __format__(): 621. (used by *note str(): 44f, *note format(): 622.
     and *note f-string: 439.s).

   * Changed *note Enum.__format__(): 623. (the default for *note
     format(): 622, *note str.format(): 624. and *note f-string: 439.s)
     to always produce the same result as *note Enum.__str__(): 625.:
     for enums inheriting from *note ReprEnum: 61e. it will be the
     member’s value; for all other enums it will be the enum and member
     name (e.g.  ‘Color.RED’).

   * Added a new 'boundary' class parameter to *note Flag: 626. enums
     and the *note FlagBoundary: 627. enum with its options, to control
     how to handle out-of-range flag values.

   * Added the *note verify(): 628. enum decorator and the *note
     EnumCheck: 629. enum with its options, to check enum classes
     against several specific constraints.

   * Added the *note member(): 62a. and *note nonmember(): 62b.
     decorators, to ensure the decorated object is/is not converted to
     an enum member.

   * Added the *note property(): 62c. decorator, which works like *note
     property(): 194. except for enums.  Use this instead of *note
     types.DynamicClassAttribute(): 62d.

   * Added the *note global_enum(): 62e. enum decorator, which adjusts
     *note __repr__(): 61f. and *note __str__(): 620. to show values as
     members of their module rather than the enum class.  For example,
     ‘'re.ASCII'’ for the *note ASCII: 62f. member of *note
     re.RegexFlag: 630. rather than ‘'RegexFlag.ASCII'’.

   * Enhanced *note Flag: 626. to support *note len(): 631, iteration
     and *note in: 2f4./*note not in: 632. on its members.  For example,
     the following now works: ‘len(AFlag(3)) == 2 and list(AFlag(3)) ==
     (AFlag.ONE, AFlag.TWO)’

   * Changed *note Enum: 633. and *note Flag: 626. so that members are
     now defined before *note __init_subclass__(): 634. is called; *note
     dir(): 635. now includes methods, etc., from mixed-in data types.

   * Changed *note Flag: 626. to only consider primary values (power of
     two) canonical while composite values (‘3’, ‘6’, ‘10’, etc.)  are
     considered aliases; inverted flags are coerced to their positive
     equivalent.


File: python.info,  Node: fcntl,  Next: fractions<3>,  Prev: enum<3>,  Up: Improved Modules<3>

1.3.7.6 fcntl
.............

   * On FreeBSD, the ‘F_DUP2FD’ and ‘F_DUP2FD_CLOEXEC’ flags
     respectively are supported, the former equals to ‘dup2’ usage while
     the latter set the ‘FD_CLOEXEC’ flag in addition.


File: python.info,  Node: fractions<3>,  Next: functools,  Prev: fcntl,  Up: Improved Modules<3>

1.3.7.7 fractions
.................

   * Support PEP 515(1)-style initialization of *note Fraction: 1e7.
     from string.  (Contributed by Sergey B Kirpichev in bpo-44258(2).)

   * *note Fraction: 1e7. now implements an ‘__int__’ method, so that an
     ‘isinstance(some_fraction, typing.SupportsInt)’ check passes.
     (Contributed by Mark Dickinson in bpo-44547(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0515/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44258

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44547


File: python.info,  Node: functools,  Next: gzip<2>,  Prev: fractions<3>,  Up: Improved Modules<3>

1.3.7.8 functools
.................

   * *note functools.singledispatch(): 63c. now supports *note
     types.UnionType: 63d. and *note typing.Union: 63e. as annotations
     to the dispatch argument.:

          >>> from functools import singledispatch
          >>> @singledispatch
          ... def fun(arg, verbose=False):
          ...     if verbose:
          ...         print("Let me just say,", end=" ")
          ...     print(arg)
          ...
          >>> @fun.register
          ... def _(arg: int | float, verbose=False):
          ...     if verbose:
          ...         print("Strength in numbers, eh?", end=" ")
          ...     print(arg)
          ...
          >>> from typing import Union
          >>> @fun.register
          ... def _(arg: Union[list, set], verbose=False):
          ...     if verbose:
          ...         print("Enumerate this:")
          ...     for i, elem in enumerate(arg):
          ...         print(i, elem)
          ...

     (Contributed by Yurii Karabas in bpo-46014(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46014


File: python.info,  Node: gzip<2>,  Next: hashlib<2>,  Prev: functools,  Up: Improved Modules<3>

1.3.7.9 gzip
............

   * The *note gzip.compress(): 641. function is now faster when used
     with the 'mtime=0' argument as it delegates the compression
     entirely to a single *note zlib.compress(): 642. operation.  There
     is one side effect of this change: The gzip file header contains an
     “OS” byte in its header.  That was traditionally always set to a
     value of 255 representing “unknown” by the *note gzip: 67. module.
     Now, when using ‘compress()’ with 'mtime=0', it may be set to a
     different value by the underlying zlib C library Python was linked
     against.  (See gh-112346(1) for details on the side effect.)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112346


File: python.info,  Node: hashlib<2>,  Next: IDLE and idlelib,  Prev: gzip<2>,  Up: Improved Modules<3>

1.3.7.10 hashlib
................

   * *note hashlib.blake2b(): 645. and *note hashlib.blake2s(): 646. now
     prefer libb2(1) over Python’s vendored copy.  (Contributed by
     Christian Heimes in bpo-47095(2).)

   * The internal ‘_sha3’ module with SHA3 and SHAKE algorithms now uses
     'tiny_sha3' instead of the 'Keccak Code Package' to reduce code and
     binary size.  The *note hashlib: 68. module prefers optimized SHA3
     and SHAKE implementations from OpenSSL. The change affects only
     installations without OpenSSL support.  (Contributed by Christian
     Heimes in bpo-47098(3).)

   * Add *note hashlib.file_digest(): 647, a helper function for
     efficient hashing of files or file-like objects.  (Contributed by
     Christian Heimes in gh-89313(4).)

   ---------- Footnotes ----------

   (1) https://www.blake2.net/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47095

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47098

   (4) https://github.com/python/cpython/issues/89313


File: python.info,  Node: IDLE and idlelib,  Next: inspect<2>,  Prev: hashlib<2>,  Up: Improved Modules<3>

1.3.7.11 IDLE and idlelib
.........................

   * Apply syntax highlighting to ‘.pyi’ files.  (Contributed by Alex
     Waygood and Terry Jan Reedy in bpo-45447(1).)

   * Include prompts when saving Shell with inputs and outputs.
     (Contributed by Terry Jan Reedy in gh-95191(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45447

   (2) https://github.com/python/cpython/issues/95191


File: python.info,  Node: inspect<2>,  Next: locale<3>,  Prev: IDLE and idlelib,  Up: Improved Modules<3>

1.3.7.12 inspect
................

   * Add *note getmembers_static(): 64c. to return all members without
     triggering dynamic lookup via the descriptor protocol.
     (Contributed by Weipeng Hong in bpo-30533(1).)

   * Add *note ismethodwrapper(): 64d. for checking if the type of an
     object is a *note MethodWrapperType: 64e.  (Contributed by Hakan
     Çelik in bpo-29418(2).)

   * Change the frame-related functions in the *note inspect: 7e. module
     to return new *note FrameInfo: 64f. and *note Traceback: 650. class
     instances (backwards compatible with the previous *note named
     tuple: 651.-like interfaces) that includes the extended PEP 657(3)
     position information (end line number, column and end column).  The
     affected functions are:

        * *note inspect.getframeinfo(): 652.

        * *note inspect.getouterframes(): 653.

        * *note inspect.getinnerframes(): 654,

        * *note inspect.stack(): 655.

        * *note inspect.trace(): 656.

     (Contributed by Pablo Galindo in gh-88116(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30533

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29418

   (3) https://peps.python.org/pep-0657/

   (4) https://github.com/python/cpython/issues/88116


File: python.info,  Node: locale<3>,  Next: logging,  Prev: inspect<2>,  Up: Improved Modules<3>

1.3.7.13 locale
...............

   * Add *note locale.getencoding(): 2dc. to get the current locale
     encoding.  It is similar to ‘locale.getpreferredencoding(False)’
     but ignores the *note Python UTF-8 Mode: 659.


File: python.info,  Node: logging,  Next: math<3>,  Prev: locale<3>,  Up: Improved Modules<3>

1.3.7.14 logging
................

   * Added *note getLevelNamesMapping(): 65c. to return a mapping from
     logging level names (e.g.  ‘'CRITICAL'’) to the values of their
     corresponding *note Logging Levels: 65d. (e.g.  ‘50’, by default).
     (Contributed by Andrei Kulakovin in gh-88024(1).)

   * Added a *note createSocket(): 65e. method to *note SysLogHandler:
     65f, to match *note SocketHandler.createSocket(): 660.  It is
     called automatically during handler initialization and when
     emitting an event, if there is no active socket.  (Contributed by
     Kirill Pinchuk in gh-88457(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88024

   (2) https://github.com/python/cpython/issues/88457


File: python.info,  Node: math<3>,  Next: operator,  Prev: logging,  Up: Improved Modules<3>

1.3.7.15 math
.............

   * Add *note math.exp2(): 663.: return 2 raised to the power of x.
     (Contributed by Gideon Mitchell in bpo-45917(1).)

   * Add *note math.cbrt(): 664.: return the cube root of x.
     (Contributed by Ajith Ramachandran in bpo-44357(2).)

   * The behaviour of two *note math.pow(): 665. corner cases was
     changed, for consistency with the IEEE 754 specification.  The
     operations ‘math.pow(0.0, -math.inf)’ and ‘math.pow(-0.0,
     -math.inf)’ now return ‘inf’.  Previously they raised *note
     ValueError: 202.  (Contributed by Mark Dickinson in bpo-44339(3).)

   * The *note math.nan: 666. value is now always available.
     (Contributed by Victor Stinner in bpo-46917(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45917

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44357

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44339

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46917


File: python.info,  Node: operator,  Next: os<3>,  Prev: math<3>,  Up: Improved Modules<3>

1.3.7.16 operator
.................

   * A new function ‘operator.call’ has been added, such that
     ‘operator.call(obj, *args, **kwargs) == obj(*args, **kwargs)’.
     (Contributed by Antony Lee in bpo-44019(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44019


File: python.info,  Node: os<3>,  Next: pathlib<4>,  Prev: operator,  Up: Improved Modules<3>

1.3.7.17 os
...........

   * On Windows, *note os.urandom(): 526. now uses ‘BCryptGenRandom()’,
     instead of ‘CryptGenRandom()’ which is deprecated.  (Contributed by
     Donghee Na in bpo-44611(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44611


File: python.info,  Node: pathlib<4>,  Next: re<3>,  Prev: os<3>,  Up: Improved Modules<3>

1.3.7.18 pathlib
................

   * *note glob(): 22d. and *note rglob(): 22e. return only directories
     if 'pattern' ends with a pathname components separator: *note sep:
     66d. or *note altsep: 66e.  (Contributed by Eisuke Kawasima in
     bpo-22276(1) and bpo-33392(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22276

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33392


File: python.info,  Node: re<3>,  Next: shutil<3>,  Prev: pathlib<4>,  Up: Improved Modules<3>

1.3.7.19 re
...........

   * Atomic grouping (‘(?>...)’) and possessive quantifiers (‘*+’, ‘++’,
     ‘?+’, ‘{m,n}+’) are now supported in regular expressions.
     (Contributed by Jeffrey C. Jacobs and Serhiy Storchaka in
     bpo-433030(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=433030


File: python.info,  Node: shutil<3>,  Next: socket,  Prev: re<3>,  Up: Improved Modules<3>

1.3.7.20 shutil
...............

   * Add optional parameter 'dir_fd' in *note shutil.rmtree(): 301.
     (Contributed by Serhiy Storchaka in bpo-46245(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46245


File: python.info,  Node: socket,  Next: sqlite3<4>,  Prev: shutil<3>,  Up: Improved Modules<3>

1.3.7.21 socket
...............

   * Add CAN Socket support for NetBSD. (Contributed by Thomas Klausner
     in bpo-30512(1).)

   * *note create_connection(): 675. has an option to raise, in case of
     failure to connect, an *note ExceptionGroup: 1b6. containing all
     errors instead of only raising the last error.  (Contributed by
     Irit Katriel in bpo-29980(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30512

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29980


File: python.info,  Node: sqlite3<4>,  Next: string,  Prev: socket,  Up: Improved Modules<3>

1.3.7.22 sqlite3
................

   * You can now disable the authorizer by passing *note None: 678. to
     *note set_authorizer(): 2ab.  (Contributed by Erlend E. Aasland in
     bpo-44491(1).)

   * Collation name *note create_collation(): 679. can now contain any
     Unicode character.  Collation names with invalid characters now
     raise *note UnicodeEncodeError: 67a. instead of *note
     sqlite3.ProgrammingError: 4f5.  (Contributed by Erlend E. Aasland
     in bpo-44688(2).)

   * *note sqlite3: cf. exceptions now include the SQLite extended error
     code as *note sqlite_errorcode: 67b. and the SQLite error name as
     *note sqlite_errorname: 67c.  (Contributed by Aviv Palivoda, Daniel
     Shahaf, and Erlend E. Aasland in bpo-16379(3) and bpo-24139(4).)

   * Add *note setlimit(): 67d. and *note getlimit(): 67e. to *note
     sqlite3.Connection: 245. for setting and getting SQLite limits by
     connection basis.  (Contributed by Erlend E. Aasland in
     bpo-45243(5).)

   * *note sqlite3: cf. now sets *note sqlite3.threadsafety: 67f. based
     on the default threading mode the underlying SQLite library has
     been compiled with.  (Contributed by Erlend E. Aasland in
     bpo-45613(6).)

   * *note sqlite3: cf. C callbacks now use unraisable exceptions if
     callback tracebacks are enabled.  Users can now register an *note
     unraisable hook handler: 1f7. to improve their debug experience.
     (Contributed by Erlend E. Aasland in bpo-45828(7).)

   * Fetch across rollback no longer raises *note InterfaceError: 680.
     Instead we leave it to the SQLite library to handle these cases.
     (Contributed by Erlend E. Aasland in bpo-44092(8).)

   * Add *note serialize(): 681. and *note deserialize(): 682. to *note
     sqlite3.Connection: 245. for serializing and deserializing
     databases.  (Contributed by Erlend E. Aasland in bpo-41930(9).)

   * Add *note create_window_function(): 683. to *note
     sqlite3.Connection: 245. for creating aggregate window functions.
     (Contributed by Erlend E. Aasland in bpo-34916(10).)

   * Add *note blobopen(): 684. to *note sqlite3.Connection: 245.  *note
     sqlite3.Blob: 685. allows incremental I/O operations on blobs.
     (Contributed by Aviv Palivoda and Erlend E. Aasland in
     bpo-24905(11).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44491

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44688

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16379

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24139

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45243

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45613

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45828

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44092

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41930

   (10) https://bugs.python.org/issue?@action=redirect&bpo=34916

   (11) https://bugs.python.org/issue?@action=redirect&bpo=24905


File: python.info,  Node: string,  Next: sys<4>,  Prev: sqlite3<4>,  Up: Improved Modules<3>

1.3.7.23 string
...............

   * Add *note get_identifiers(): 688. and *note is_valid(): 689. to
     *note string.Template: 68a, which respectively return all valid
     placeholders, and whether any invalid placeholders are present.
     (Contributed by Ben Kehoe in gh-90465(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/90465


File: python.info,  Node: sys<4>,  Next: sysconfig,  Prev: string,  Up: Improved Modules<3>

1.3.7.24 sys
............

   * *note sys.exc_info(): 68d. now derives the ‘type’ and ‘traceback’
     fields from the ‘value’ (the exception instance), so when an
     exception is modified while it is being handled, the changes are
     reflected in the results of subsequent calls to ‘exc_info()’.
     (Contributed by Irit Katriel in bpo-45711(1).)

   * Add *note sys.exception(): 68e. which returns the active exception
     instance (equivalent to ‘sys.exc_info()[1]’).  (Contributed by Irit
     Katriel in bpo-46328(2).)

   * Add the *note sys.flags.safe_path: 68f. flag.  (Contributed by
     Victor Stinner in gh-57684(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46328

   (3) https://github.com/python/cpython/issues/57684


File: python.info,  Node: sysconfig,  Next: tempfile<3>,  Prev: sys<4>,  Up: Improved Modules<3>

1.3.7.25 sysconfig
..................

   * Three new *note installation schemes: 692. ('posix_venv', 'nt_venv'
     and 'venv') were added and are used when Python creates new virtual
     environments or when it is running from a virtual environment.  The
     first two schemes ('posix_venv' and 'nt_venv') are OS-specific for
     non-Windows and Windows, the 'venv' is essentially an alias to one
     of them according to the OS Python runs on.  This is useful for
     downstream distributors who modify *note
     sysconfig.get_preferred_scheme(): 693.  Third party code that
     creates new virtual environments should use the new 'venv'
     installation scheme to determine the paths, as does *note venv:
     111.  (Contributed by Miro Hrončok in bpo-45413(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45413


File: python.info,  Node: tempfile<3>,  Next: threading<2>,  Prev: sysconfig,  Up: Improved Modules<3>

1.3.7.26 tempfile
.................

   * *note SpooledTemporaryFile: 696. objects now fully implement the
     methods of *note io.BufferedIOBase: 697. or *note io.TextIOBase:
     698. (depending on file mode).  This lets them work correctly with
     APIs that expect file-like objects, such as compression modules.
     (Contributed by Carey Metcalfe in gh-70363(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/70363


File: python.info,  Node: threading<2>,  Next: time<2>,  Prev: tempfile<3>,  Up: Improved Modules<3>

1.3.7.27 threading
..................

   * On Unix, if the ‘sem_clockwait()’ function is available in the C
     library (glibc 2.30 and newer), the *note threading.Lock.acquire():
     69b. method now uses the monotonic clock (*note
     time.CLOCK_MONOTONIC: 69c.) for the timeout, rather than using the
     system clock (*note time.CLOCK_REALTIME: 69d.), to not be affected
     by system clock changes.  (Contributed by Victor Stinner in
     bpo-41710(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41710


File: python.info,  Node: time<2>,  Next: tkinter<3>,  Prev: threading<2>,  Up: Improved Modules<3>

1.3.7.28 time
.............

   * On Unix, *note time.sleep(): 6a0. now uses the ‘clock_nanosleep()’
     or ‘nanosleep()’ function, if available, which has a resolution of
     1 nanosecond (10^-9 seconds), rather than using ‘select()’ which
     has a resolution of 1 microsecond (10^-6 seconds).  (Contributed by
     Benjamin Szőke and Victor Stinner in bpo-21302(1).)

   * On Windows 8.1 and newer, *note time.sleep(): 6a0. now uses a
     waitable timer based on high-resolution timers(2) which has a
     resolution of 100 nanoseconds (10^-7 seconds).  Previously, it had
     a resolution of 1 millisecond (10^-3 seconds).  (Contributed by
     Benjamin Szőke, Donghee Na, Eryk Sun and Victor Stinner in
     bpo-21302(3) and bpo-45429(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21302

   (2) 
https://docs.microsoft.com/en-us/windows-hardware/drivers/kernel/high-resolution-timers

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21302

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45429


File: python.info,  Node: tkinter<3>,  Next: traceback<2>,  Prev: time<2>,  Up: Improved Modules<3>

1.3.7.29 tkinter
................

   * Added method ‘info_patchlevel()’ which returns the exact version of
     the Tcl library as a named tuple similar to *note sys.version_info:
     6a3.  (Contributed by Serhiy Storchaka in gh-91827(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91827


File: python.info,  Node: traceback<2>,  Next: typing<4>,  Prev: tkinter<3>,  Up: Improved Modules<3>

1.3.7.30 traceback
..................

   * Add *note traceback.StackSummary.format_frame_summary(): 6a6. to
     allow users to override which frames appear in the traceback, and
     how they are formatted.  (Contributed by Ammar Askar in
     bpo-44569(1).)

   * Add *note traceback.TracebackException.print(): 6a7, which prints
     the formatted *note TracebackException: 25c. instance to a file.
     (Contributed by Irit Katriel in bpo-33809(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44569

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33809


File: python.info,  Node: typing<4>,  Next: unicodedata<3>,  Prev: traceback<2>,  Up: Improved Modules<3>

1.3.7.31 typing
...............

For major changes, see *note New Features Related to Type Hints: 5c2.

   * Add *note typing.assert_never(): 6aa. and *note typing.Never: 6ab.
     ‘typing.assert_never()’ is useful for asking a type checker to
     confirm that a line of code is not reachable.  At runtime, it
     raises an *note AssertionError: 6ac.  (Contributed by Jelle
     Zijlstra in gh-90633(1).)

   * Add *note typing.reveal_type(): 6ad.  This is useful for asking a
     type checker what type it has inferred for a given expression.  At
     runtime it prints the type of the received value.  (Contributed by
     Jelle Zijlstra in gh-90572(2).)

   * Add *note typing.assert_type(): 6ae.  This is useful for asking a
     type checker to confirm that the type it has inferred for a given
     expression matches the given type.  At runtime it simply returns
     the received value.  (Contributed by Jelle Zijlstra in
     gh-90638(3).)

   * *note typing.TypedDict: 162. types can now be generic.
     (Contributed by Samodya Abeysiriwardane in gh-89026(4).)

   * *note NamedTuple: 2b0. types can now be generic.  (Contributed by
     Serhiy Storchaka in bpo-43923(5).)

   * Allow subclassing of *note typing.Any: 6af.  This is useful for
     avoiding type checker errors related to highly dynamic class, such
     as mocks.  (Contributed by Shantanu Jain in gh-91154(6).)

   * The *note typing.final(): 6b0. decorator now sets the ‘__final__’
     attributed on the decorated object.  (Contributed by Jelle Zijlstra
     in gh-90500(7).)

   * The *note typing.get_overloads(): 6b1. function can be used for
     introspecting the overloads of a function.  *note
     typing.clear_overloads(): 6b2. can be used to clear all registered
     overloads of a function.  (Contributed by Jelle Zijlstra in
     gh-89263(8).)

   * The *note __init__(): 6b3. method of *note Protocol: 264.
     subclasses is now preserved.  (Contributed by Adrian Garcia
     Badarasco in gh-88970(9).)

   * The representation of empty tuple types (‘Tuple[()]’) is
     simplified.  This affects introspection, e.g.
     ‘get_args(Tuple[()])’ now evaluates to ‘()’ instead of ‘((),)’.
     (Contributed by Serhiy Storchaka in gh-91137(10).)

   * Loosen runtime requirements for type annotations by removing the
     callable check in the private ‘typing._type_check’ function.
     (Contributed by Gregory Beauregard in gh-90802(11).)

   * *note typing.get_type_hints(): 6b4. now supports evaluating strings
     as forward references in *note PEP 585 generic aliases: 6b5.
     (Contributed by Niklas Rosenstein in gh-85542(12).)

   * *note typing.get_type_hints(): 6b4. no longer adds *note Optional:
     6b6. to parameters with ‘None’ as a default.  (Contributed by
     Nikita Sobolev in gh-90353(13).)

   * *note typing.get_type_hints(): 6b4. now supports evaluating bare
     stringified *note ClassVar: 266. annotations.  (Contributed by
     Gregory Beauregard in gh-90711(14).)

   * *note typing.no_type_check(): 6b7. no longer modifies external
     classes and functions.  It also now correctly marks classmethods as
     not to be type checked.  (Contributed by Nikita Sobolev in
     gh-90729(15).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/90633

   (2) https://github.com/python/cpython/issues/90572

   (3) https://github.com/python/cpython/issues/90638

   (4) https://github.com/python/cpython/issues/89026

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43923

   (6) https://github.com/python/cpython/issues/91154

   (7) https://github.com/python/cpython/issues/90500

   (8) https://github.com/python/cpython/issues/89263

   (9) https://github.com/python/cpython/issues/88970

   (10) https://github.com/python/cpython/issues/91137

   (11) https://github.com/python/cpython/issues/90802

   (12) https://github.com/python/cpython/issues/85542

   (13) https://github.com/python/cpython/issues/90353

   (14) https://github.com/python/cpython/issues/90711

   (15) https://github.com/python/cpython/issues/90729


File: python.info,  Node: unicodedata<3>,  Next: unittest<4>,  Prev: typing<4>,  Up: Improved Modules<3>

1.3.7.32 unicodedata
....................

   * The Unicode database has been updated to version 14.0.0.
     (Contributed by Benjamin Peterson in bpo-45190(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45190


File: python.info,  Node: unittest<4>,  Next: venv<2>,  Prev: unicodedata<3>,  Up: Improved Modules<3>

1.3.7.33 unittest
.................

   * Added methods *note enterContext(): 6bc. and *note
     enterClassContext(): 6bd. of class *note TestCase: 451, method
     *note enterAsyncContext(): 6be. of class *note
     IsolatedAsyncioTestCase: 30c. and function *note
     unittest.enterModuleContext(): 6bf.  (Contributed by Serhiy
     Storchaka in bpo-45046(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45046


File: python.info,  Node: venv<2>,  Next: warnings<2>,  Prev: unittest<4>,  Up: Improved Modules<3>

1.3.7.34 venv
.............

   * When new Python virtual environments are created, the 'venv' *note
     sysconfig installation scheme: 692. is used to determine the paths
     inside the environment.  When Python runs in a virtual environment,
     the same installation scheme is the default.  That means that
     downstream distributors can change the default sysconfig install
     scheme without changing behavior of virtual environments.  Third
     party code that also creates new virtual environments should do the
     same.  (Contributed by Miro Hrončok in bpo-45413(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45413


File: python.info,  Node: warnings<2>,  Next: zipfile,  Prev: venv<2>,  Up: Improved Modules<3>

1.3.7.35 warnings
.................

   * *note warnings.catch_warnings(): 587. now accepts arguments for
     *note warnings.simplefilter(): 6c4, providing a more concise way to
     locally ignore warnings or convert them to errors.  (Contributed by
     Zac Hatfield-Dodds in bpo-47074(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47074


File: python.info,  Node: zipfile,  Prev: warnings<2>,  Up: Improved Modules<3>

1.3.7.36 zipfile
................

   * Added support for specifying member name encoding for reading
     metadata in a *note ZipFile: 6c7.’s directory and file headers.
     (Contributed by Stephen J. Turnbull and Serhiy Storchaka in
     bpo-28080(1).)

   * Added *note ZipFile.mkdir(): 6c8. for creating new directories
     inside ZIP archives.  (Contributed by Sam Ezeh in gh-49083(2).)

   * Added *note stem: 6c9, *note suffix: 6ca. and *note suffixes: 6cb.
     to *note zipfile.Path: 6cc.  (Contributed by Miguel Brito in
     gh-88261(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28080

   (2) https://github.com/python/cpython/issues/49083

   (3) https://github.com/python/cpython/issues/88261


File: python.info,  Node: Optimizations<3>,  Next: Faster CPython,  Prev: Improved Modules<3>,  Up: What’s New In Python 3 11

1.3.8 Optimizations
-------------------

This section covers specific optimizations independent of the *note
Faster CPython: 5a3. project, which is covered in its own section.

   * The compiler now optimizes simple *note printf-style % formatting:
     6cf. on string literals containing only the format codes ‘%s’, ‘%r’
     and ‘%a’ and makes it as fast as a corresponding *note f-string:
     439. expression.  (Contributed by Serhiy Storchaka in
     bpo-28307(1).)

   * Integer division (‘//’) is better tuned for optimization by
     compilers.  It is now around 20% faster on x86-64 when dividing an
     *note int: 257. by a value smaller than ‘2**30’.  (Contributed by
     Gregory P. Smith and Tim Peters in gh-90564(2).)

   * *note sum(): 46d. is now nearly 30% faster for integers smaller
     than ‘2**30’.  (Contributed by Stefan Behnel in gh-68264(3).)

   * Resizing lists is streamlined for the common case, speeding up
     *note list.append(): 6d0. by ≈15% and simple *note list
     comprehension: 6d1.s by up to 20-30% (Contributed by Dennis Sweeney
     in gh-91165(4).)

   * Dictionaries don’t store hash values when all keys are Unicode
     objects, decreasing *note dict: 256. size.  For example,
     ‘sys.getsizeof(dict.fromkeys("abcdefg"))’ is reduced from 352 bytes
     to 272 bytes (23% smaller) on 64-bit platforms.  (Contributed by
     Inada Naoki in bpo-46845(5).)

   * Using *note asyncio.DatagramProtocol: 6d2. is now orders of
     magnitude faster when transferring large files over UDP, with
     speeds over 100 times higher for a ≈60 MiB file.  (Contributed by
     msoxzw in gh-91487(6).)

   * *note math: 8e. functions *note comb(): 6d3. and *note perm(): 6d4.
     are now ≈10 times faster for large arguments (with a larger speedup
     for larger 'k').  (Contributed by Serhiy Storchaka in
     bpo-37295(7).)

   * The *note statistics: d2. functions *note mean(): 6d5, *note
     variance(): 6d6. and *note stdev(): 6d7. now consume iterators in
     one pass rather than converting them to a *note list: 614. first.
     This is twice as fast and can save substantial memory.
     (Contributed by Raymond Hettinger in gh-90415(8).)

   * *note unicodedata.normalize(): 6d8. now normalizes pure-ASCII
     strings in constant time.  (Contributed by Donghee Na in
     bpo-44987(9).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28307

   (2) https://github.com/python/cpython/issues/90564

   (3) https://github.com/python/cpython/issues/68264

   (4) https://github.com/python/cpython/issues/91165

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46845

   (6) https://github.com/python/cpython/issues/91487

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37295

   (8) https://github.com/python/cpython/issues/90415

   (9) https://bugs.python.org/issue?@action=redirect&bpo=44987


File: python.info,  Node: Faster CPython,  Next: CPython bytecode changes<2>,  Prev: Optimizations<3>,  Up: What’s New In Python 3 11

1.3.9 Faster CPython
--------------------

CPython 3.11 is an average of 25% faster(1) than CPython 3.10 as
measured with the pyperformance(2) benchmark suite, when compiled with
GCC on Ubuntu Linux.  Depending on your workload, the overall speedup
could be 10-60%.

This project focuses on two major areas in Python: *note Faster Startup:
6da. and *note Faster Runtime: 6db.  Optimizations not covered by this
project are listed separately under *note Optimizations: 6ce.

* Menu:

* Faster Startup::
* Faster Runtime::
* Misc::
* FAQ::
* About::

   ---------- Footnotes ----------

   (1) https://github.com/faster-cpython/ideas#published-results

   (2) https://github.com/python/pyperformance


File: python.info,  Node: Faster Startup,  Next: Faster Runtime,  Up: Faster CPython

1.3.9.1 Faster Startup
......................

* Menu:

* Frozen imports / Static code objects::


File: python.info,  Node: Frozen imports / Static code objects,  Up: Faster Startup

1.3.9.2 Frozen imports / Static code objects
............................................

Python caches *note bytecode: 187. in the *note __pycache__: 6df.
directory to speed up module loading.

Previously in 3.10, Python module execution looked like this:

     Read __pycache__ -> Unmarshal -> Heap allocated code object -> Evaluate

In Python 3.11, the core modules essential for Python startup are
“frozen”.  This means that their *note Code Objects: 5b8. (and bytecode)
are statically allocated by the interpreter.  This reduces the steps in
module execution process to:

     Statically allocated code object -> Evaluate

Interpreter startup is now 10-15% faster in Python 3.11.  This has a big
impact for short-running programs using Python.

(Contributed by Eric Snow, Guido van Rossum and Kumar Aditya in many
issues.)


File: python.info,  Node: Faster Runtime,  Next: Misc,  Prev: Faster Startup,  Up: Faster CPython

1.3.9.3 Faster Runtime
......................

* Menu:

* Cheaper, lazy Python frames: Cheaper lazy Python frames.
* Inlined Python function calls::
* PEP 659; Specializing Adaptive Interpreter: PEP 659 Specializing Adaptive Interpreter.


File: python.info,  Node: Cheaper lazy Python frames,  Next: Inlined Python function calls,  Up: Faster Runtime

1.3.9.4 Cheaper, lazy Python frames
...................................

Python frames, holding execution information, are created whenever
Python calls a Python function.  The following are new frame
optimizations:

   - Streamlined the frame creation process.

   - Avoided memory allocation by generously re-using frame space on the
     C stack.

   - Streamlined the internal frame struct to contain only essential
     information.  Frames previously held extra debugging and memory
     management information.

Old-style *note frame objects: 6e3. are now created only when requested
by debuggers or by Python introspection functions such as *note
sys._getframe(): 6e4. and *note inspect.currentframe(): 6e5.  For most
user code, no frame objects are created at all.  As a result, nearly all
Python functions calls have sped up significantly.  We measured a 3-7%
speedup in pyperformance.

(Contributed by Mark Shannon in bpo-44590(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44590


File: python.info,  Node: Inlined Python function calls,  Next: PEP 659 Specializing Adaptive Interpreter,  Prev: Cheaper lazy Python frames,  Up: Faster Runtime

1.3.9.5 Inlined Python function calls
.....................................

During a Python function call, Python will call an evaluating C function
to interpret that function’s code.  This effectively limits pure Python
recursion to what’s safe for the C stack.

In 3.11, when CPython detects Python code calling another Python
function, it sets up a new frame, and “jumps” to the new code inside the
new frame.  This avoids calling the C interpreting function altogether.

Most Python function calls now consume no C stack space, speeding them
up.  In simple recursive functions like fibonacci or factorial, we
observed a 1.7x speedup.  This also means recursive functions can
recurse significantly deeper (if the user increases the recursion limit
with *note sys.setrecursionlimit(): 4c6.).  We measured a 1-3%
improvement in pyperformance.

(Contributed by Pablo Galindo and Mark Shannon in bpo-45256(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45256


File: python.info,  Node: PEP 659 Specializing Adaptive Interpreter,  Prev: Inlined Python function calls,  Up: Faster Runtime

1.3.9.6 PEP 659: Specializing Adaptive Interpreter
..................................................

PEP 659(1) is one of the key parts of the Faster CPython project.  The
general idea is that while Python is a dynamic language, most code has
regions where objects and types rarely change.  This concept is known as
'type stability'.

At runtime, Python will try to look for common patterns and type
stability in the executing code.  Python will then replace the current
operation with a more specialized one.  This specialized operation uses
fast paths available only to those use cases/types, which generally
outperform their generic counterparts.  This also brings in another
concept called 'inline caching', where Python caches the results of
expensive operations directly in the *note bytecode: 187.

The specializer will also combine certain common instruction pairs into
one superinstruction, reducing the overhead during execution.

Python will only specialize when it sees code that is “hot” (executed
multiple times).  This prevents Python from wasting time on run-once
code.  Python can also de-specialize when code is too dynamic or when
the use changes.  Specialization is attempted periodically, and
specialization attempts are not too expensive, allowing specialization
to adapt to new circumstances.

(PEP written by Mark Shannon, with ideas inspired by Stefan Brunthaler.
See PEP 659(2) for more information.  Implementation by Mark Shannon and
Brandt Bucher, with additional help from Irit Katriel and Dennis
Sweeney.)

Operation           Form                     Specialization                                              Operation speedup (up   Contributor(s)
                                                                                                         to)                     
                                                                                                         
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                 
Binary operations   ‘x + x’                  Binary add, multiply and subtract for common types such     10%                     Mark Shannon, Donghee
                                             as *note int: 257, *note float: 2f7. and *note str: 44f.                            Na, Brandt Bucher,
                    ‘x - x’                  take custom fast paths for their underlying types.                                  Dennis Sweeney
                                                                                                                                 
                    ‘x * x’
                    
                                                                                                                                 
Subscript           ‘a[i]’                   Subscripting container types such as *note list: 614,       10-25%                  Irit Katriel, Mark
                                             *note tuple: 373. and *note dict: 256. directly index the                           Shannon
                                             underlying data structures.                                                         
                                             
                                             Subscripting custom *note __getitem__(): 283. is also
                                             inlined similar to
                                             *note Inlined Python function calls: 6e6.
                                             
                                                                                                                                 
Store subscript     ‘a[i] = z’               Similar to subscripting specialization above.               10-25%                  Dennis Sweeney
                                                                                                                                 
                                                                                                                                 
Calls               ‘f(arg)’                 Calls to common builtin (C) functions and types such as     20%                     Mark Shannon, Ken Jin
                                             *note len(): 631. and *note str: 44f. directly call their                           
                    ‘C(arg)’                 underlying C version.  This avoids going through the
                                             internal calling convention.
                                             
                                                                                                                                 
Load global         ‘print’                  The object’s index in the globals/builtins namespace is     (3)                     Mark Shannon
variable                                     cached.  Loading globals and builtins require zero                                  
                    ‘len’                    namespace lookups.
                                             
                                                                                                                                 
Load attribute      ‘o.attr’                 Similar to loading global variables.  The attribute’s       (4)                     Mark Shannon
                                             index inside the class/object’s namespace is cached.  In                            
                                             most cases, attribute loading will require zero namespace
                                             lookups.
                                             
                                                                                                                                 
Load methods for    ‘o.meth()’               The actual address of the method is cached.  Method         10-20%                  Ken Jin, Mark Shannon
call                                         loading now has no namespace lookups – even for classes                             
                                             with long inheritance chains.
                                             
                                                                                                                                 
Store attribute     ‘o.attr = z’             Similar to load attribute optimization.                     2% in pyperformance     Mark Shannon
                                                                                                                                 
                                                                                                                                 
Unpack Sequence     ‘*seq’                   Specialized for common containers such as                   8%                      Brandt Bucher
                                             *note list: 614. and *note tuple: 373.  Avoids internal                             
                                             calling convention.
                                             

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0659/

   (2) https://peps.python.org/pep-0659/

   (3) A similar optimization already existed since Python 3.8.  3.11
specializes for more forms and reduces some overhead.

   (4) A similar optimization already existed since Python 3.10.  3.11
specializes for more forms.  Furthermore, all attribute loads should be
sped up by bpo-45947
(https://bugs.python.org/issue?@action=redirect&bpo=45947).


File: python.info,  Node: Misc,  Next: FAQ,  Prev: Faster Runtime,  Up: Faster CPython

1.3.9.7 Misc
............

   * Objects now require less memory due to lazily created object
     namespaces.  Their namespace dictionaries now also share keys more
     freely.  (Contributed Mark Shannon in bpo-45340(1) and
     bpo-40116(2).)

   * “Zero-cost” exceptions are implemented, eliminating the cost of
     *note try: 6ec. statements when no exception is raised.
     (Contributed by Mark Shannon in bpo-40222(3).)

   * A more concise representation of exceptions in the interpreter
     reduced the time required for catching an exception by about 10%.
     (Contributed by Irit Katriel in bpo-45711(4).)

   * *note re: b9.’s regular expression matching engine has been
     partially refactored, and now uses computed gotos (or “threaded
     code”) on supported platforms.  As a result, Python 3.11 executes
     the pyperformance regular expression benchmarks(5) up to 10% faster
     than Python 3.10.  (Contributed by Brandt Bucher in gh-91404(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45340

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40116

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40222

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (5) https://pyperformance.readthedocs.io/benchmarks.html#regex-dna

   (6) https://github.com/python/cpython/issues/91404


File: python.info,  Node: FAQ,  Next: About,  Prev: Misc,  Up: Faster CPython

1.3.9.8 FAQ
...........

* Menu:

* How should I write my code to utilize these speedups?::
* Will CPython 3.11 use more memory?: Will CPython 3 11 use more memory?.
* I don’t see any speedups in my workload. Why?: I don’t see any speedups in my workload Why?.
* Is there a JIT compiler?::


File: python.info,  Node: How should I write my code to utilize these speedups?,  Next: Will CPython 3 11 use more memory?,  Up: FAQ

1.3.9.9 How should I write my code to utilize these speedups?
.............................................................

Write Pythonic code that follows common best practices; you don’t have
to change your code.  The Faster CPython project optimizes for common
code patterns we observe.


File: python.info,  Node: Will CPython 3 11 use more memory?,  Next: I don’t see any speedups in my workload Why?,  Prev: How should I write my code to utilize these speedups?,  Up: FAQ

1.3.9.10 Will CPython 3.11 use more memory?
...........................................

Maybe not; we don’t expect memory use to exceed 20% higher than 3.10.
This is offset by memory optimizations for frame objects and object
dictionaries as mentioned above.


File: python.info,  Node: I don’t see any speedups in my workload Why?,  Next: Is there a JIT compiler?,  Prev: Will CPython 3 11 use more memory?,  Up: FAQ

1.3.9.11 I don’t see any speedups in my workload. Why?
......................................................

Certain code won’t have noticeable benefits.  If your code spends most
of its time on I/O operations, or already does most of its computation
in a C extension library like NumPy, there won’t be significant
speedups.  This project currently benefits pure-Python workloads the
most.

Furthermore, the pyperformance figures are a geometric mean.  Even
within the pyperformance benchmarks, certain benchmarks have slowed down
slightly, while others have sped up by nearly 2x!


File: python.info,  Node: Is there a JIT compiler?,  Prev: I don’t see any speedups in my workload Why?,  Up: FAQ

1.3.9.12 Is there a JIT compiler?
.................................

No.  We’re still exploring other optimizations.


File: python.info,  Node: About,  Prev: FAQ,  Up: Faster CPython

1.3.9.13 About
..............

Faster CPython explores optimizations for *note CPython: 6f9.  The main
team is funded by Microsoft to work on this full-time.  Pablo Galindo
Salgado is also funded by Bloomberg LP to work on the project part-time.
Finally, many contributors are volunteers from the community.


File: python.info,  Node: CPython bytecode changes<2>,  Next: Deprecated<3>,  Prev: Faster CPython,  Up: What’s New In Python 3 11

1.3.10 CPython bytecode changes
-------------------------------

The bytecode now contains inline cache entries, which take the form of
the newly-added *note CACHE: 6fc. instructions.  Many opcodes expect to
be followed by an exact number of caches, and instruct the interpreter
to skip over them at runtime.  Populated caches can look like arbitrary
instructions, so great care should be taken when reading or modifying
raw, adaptive bytecode containing quickened data.

* Menu:

* New opcodes::
* Replaced opcodes::
* Changed/removed opcodes::


File: python.info,  Node: New opcodes,  Next: Replaced opcodes,  Up: CPython bytecode changes<2>

1.3.10.1 New opcodes
....................

   * ‘ASYNC_GEN_WRAP’, *note RETURN_GENERATOR: 6ff. and *note SEND: 700,
     used in generators and co-routines.

   * *note COPY_FREE_VARS: 701, which avoids needing special caller-side
     code for closures.

   * *note JUMP_BACKWARD_NO_INTERRUPT: 702, for use in certain loops
     where handling interrupts is undesirable.

   * *note MAKE_CELL: 703, to create *note Cell Objects: 704.

   * *note CHECK_EG_MATCH: 705. and ‘PREP_RERAISE_STAR’, to handle the
     *note new exception groups and except*: 5a4. added in PEP 654(1).

   * *note PUSH_EXC_INFO: 706, for use in exception handlers.

   * *note RESUME: 315, a no-op, for internal tracing, debugging and
     optimization checks.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0654/


File: python.info,  Node: Replaced opcodes,  Next: Changed/removed opcodes,  Prev: New opcodes,  Up: CPython bytecode changes<2>

1.3.10.2 Replaced opcodes
.........................

Replaced Opcode(s)                       New Opcode(s)                            Notes
                                                                                  
--------------------------------------------------------------------------------------------------------------------------------
                                                                                  
     ‘BINARY_*’                          *note BINARY_OP: 709.                    Replaced all numeric binary/in-place
     ‘INPLACE_*’                                                                  opcodes with a single opcode
                                                                                  
                                                                                  
     ‘CALL_FUNCTION’                          *note CALL: 70a.                    Decouples argument shifting for methods
     ‘CALL_FUNCTION_KW’                       ‘KW_NAMES’                          from handling of keyword arguments; allows
     ‘CALL_METHOD’                            ‘PRECALL’                           better specialization of calls
                                              *note PUSH_NULL: 70b.               
                                         
                                                                                  
     ‘DUP_TOP’                                *note COPY: 70c.                    Stack manipulation instructions
     ‘DUP_TOP_TWO’                            *note SWAP: 70d.                    
     ‘ROT_TWO’                           
     ‘ROT_THREE’
     ‘ROT_FOUR’
     ‘ROT_N’

     ‘JUMP_IF_NOT_EXC_MATCH’                  *note CHECK_EXC_MATCH: 70e.         Now performs check but doesn’t jump
                                                                                  
                                                                                  
     ‘JUMP_ABSOLUTE’                          *note JUMP_BACKWARD: 70f.           See (1); ‘TRUE’, ‘FALSE’, ‘NONE’ and
     ‘POP_JUMP_IF_FALSE’                      ‘POP_JUMP_BACKWARD_IF_*’            ‘NOT_NONE’ variants for each direction
     ‘POP_JUMP_IF_TRUE’                       ‘POP_JUMP_FORWARD_IF_*’             
                                         
                                                                                  
     ‘SETUP_WITH’                        *note BEFORE_WITH: 710.                  *note with: 5d5. block setup
     ‘SETUP_ASYNC_WITH’                                                           

   ---------- Footnotes ----------

   (1) All jump opcodes are now relative, including the existing
‘JUMP_IF_TRUE_OR_POP’ and ‘JUMP_IF_FALSE_OR_POP’.  The argument is now
an offset from the current instruction rather than an absolute location.


File: python.info,  Node: Changed/removed opcodes,  Prev: Replaced opcodes,  Up: CPython bytecode changes<2>

1.3.10.3 Changed/removed opcodes
................................

   * Changed *note MATCH_CLASS: 715. and *note MATCH_KEYS: 716. to no
     longer push an additional boolean value to indicate
     success/failure.  Instead, ‘None’ is pushed on failure in place of
     the tuple of extracted values.

   * Changed opcodes that work with exceptions to reflect them now being
     represented as one item on the stack instead of three (see
     gh-89874(1)).

   * Removed ‘COPY_DICT_WITHOUT_KEYS’, ‘GEN_START’, ‘POP_BLOCK’,
     ‘SETUP_FINALLY’ and ‘YIELD_FROM’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89874


File: python.info,  Node: Deprecated<3>,  Next: Pending Removal in Python 3 12,  Prev: CPython bytecode changes<2>,  Up: What’s New In Python 3 11

1.3.11 Deprecated
-----------------

This section lists Python APIs that have been deprecated in Python 3.11.

Deprecated C APIs are *note listed separately: 71a.
* Menu:

* Language/Builtins::
* Modules::
* Standard Library::


File: python.info,  Node: Language/Builtins,  Next: Modules,  Up: Deprecated<3>

1.3.11.1 Language/Builtins
..........................

   * Chaining *note classmethod: 166. descriptors (introduced in
     bpo-19072(1)) is now deprecated.  It can no longer be used to wrap
     other descriptors such as *note property: 194.  The core design of
     this feature was flawed and caused a number of downstream problems.
     To “pass-through” a ‘classmethod’, consider using the ‘__wrapped__’
     attribute that was added in Python 3.10.  (Contributed by Raymond
     Hettinger in gh-89519(2).)

   * Octal escapes in string and bytes literals with values larger than
     ‘0o377’ (255 in decimal) now produce a *note DeprecationWarning:
     1a5.  In a future Python version, they will raise a *note
     SyntaxWarning: 469. and eventually a *note SyntaxError: 18d.
     (Contributed by Serhiy Storchaka in gh-81548(3).)

   * The delegation of *note int(): 257. to *note __trunc__(): 71e. is
     now deprecated.  Calling ‘int(a)’ when ‘type(a)’ implements
     ‘__trunc__()’ but not *note __int__(): 71f. or *note __index__():
     720. now raises a *note DeprecationWarning: 1a5.  (Contributed by
     Zackery Spytz in bpo-44977(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19072

   (2) https://github.com/python/cpython/issues/89519

   (3) https://github.com/python/cpython/issues/81548

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44977


File: python.info,  Node: Modules,  Next: Standard Library,  Prev: Language/Builtins,  Up: Deprecated<3>

1.3.11.2 Modules
................

   * PEP 594(1) led to the deprecations of the following modules slated
     for removal in Python 3.13:

     ‘aifc’                    ‘chunk’                   ‘msilib’                  ‘pipes’                   ‘telnetlib’
                                                                                                             
                                                                                                             
     ‘audioop’                 ‘crypt’                   ‘nis’                     ‘sndhdr’                  ‘uu’
                                                                                                             
                                                                                                             
     ‘cgi’                     ‘imghdr’                  ‘nntplib’                 ‘spwd’                    ‘xdrlib’
                                                                                                             
                                                                                                             
     ‘cgitb’                   ‘mailcap’                 ‘ossaudiodev’             ‘sunau’
                                                                                   

     (Contributed by Brett Cannon in bpo-47061(2) and Victor Stinner in
     gh-68966(3).)

   * The ‘asynchat’, ‘asyncore’ and ‘smtpd’ modules have been deprecated
     since at least Python 3.6.  Their documentation and deprecation
     warnings have now been updated to note they will be removed in
     Python 3.12.  (Contributed by Hugo van Kemenade in bpo-47022(4).)

   * The ‘lib2to3’ package and ‘2to3’ tool are now deprecated and may
     not be able to parse Python 3.10 or newer.  See PEP 617(5),
     introducing the new PEG parser, for details.  (Contributed by
     Victor Stinner in bpo-40360(6).)

   * Undocumented modules ‘sre_compile’, ‘sre_constants’ and ‘sre_parse’
     are now deprecated.  (Contributed by Serhiy Storchaka in
     bpo-47152(7).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47061

   (3) https://github.com/python/cpython/issues/68966

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47022

   (5) https://peps.python.org/pep-0617/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40360

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47152


File: python.info,  Node: Standard Library,  Prev: Modules,  Up: Deprecated<3>

1.3.11.3 Standard Library
.........................

   * The following have been deprecated in *note configparser: 22. since
     Python 3.2.  Their deprecation warnings have now been updated to
     note they will be removed in Python 3.12:

        * the ‘configparser.SafeConfigParser’ class

        * the ‘configparser.ParsingError.filename’ property

        * the ‘configparser.RawConfigParser.readfp()’ method

     (Contributed by Hugo van Kemenade in bpo-45173(1).)

   * ‘configparser.LegacyInterpolation’ has been deprecated in the
     docstring since Python 3.2, and is not listed in the *note
     configparser: 22. documentation.  It now emits a *note
     DeprecationWarning: 1a5. and will be removed in Python 3.13.  Use
     *note configparser.BasicInterpolation: 725. or *note
     configparser.ExtendedInterpolation: 726. instead.  (Contributed by
     Hugo van Kemenade in bpo-46607(2).)

   * The older set of *note importlib.resources: 7b. functions were
     deprecated in favor of the replacements added in Python 3.9 and
     will be removed in a future Python version, due to not supporting
     resources located within package subdirectories:

        * ‘importlib.resources.contents()’

        * ‘importlib.resources.is_resource()’

        * ‘importlib.resources.open_binary()’

        * ‘importlib.resources.open_text()’

        * ‘importlib.resources.read_binary()’

        * ‘importlib.resources.read_text()’

        * ‘importlib.resources.path()’

   * The *note locale.getdefaultlocale(): 2d9. function is deprecated
     and will be removed in Python 3.15.  Use *note locale.setlocale():
     2db, *note locale.getpreferredencoding(False): 53d. and *note
     locale.getlocale(): 2da. functions instead.  (Contributed by Victor
     Stinner in gh-90817(3).)

   * The ‘locale.resetlocale()’ function is deprecated and will be
     removed in Python 3.13.  Use ‘locale.setlocale(locale.LC_ALL, "")’
     instead.  (Contributed by Victor Stinner in gh-90817(4).)

   * Stricter rules will now be applied for numerical group references
     and group names in *note regular expressions: 727.  Only sequences
     of ASCII digits will now be accepted as a numerical reference, and
     the group name in *note bytes: 1c2. patterns and replacement
     strings can only contain ASCII letters, digits and underscores.
     For now, a deprecation warning is raised for syntax violating these
     rules.  (Contributed by Serhiy Storchaka in gh-91760(5).)

   * In the *note re: b9. module, the ‘re.template()’ function and the
     corresponding ‘re.TEMPLATE’ and ‘re.T’ flags are deprecated, as
     they were undocumented and lacked an obvious purpose.  They will be
     removed in Python 3.13.  (Contributed by Serhiy Storchaka and Miro
     Hrončok in gh-92728(6).)

   * ‘turtle.settiltangle()’ has been deprecated since Python 3.1; it
     now emits a deprecation warning and will be removed in Python 3.13.
     Use *note turtle.tiltangle(): 728. instead (it was earlier
     incorrectly marked as deprecated, and its docstring is now
     corrected).  (Contributed by Hugo van Kemenade in bpo-45837(7).)

   * *note typing.Text: 30b, which exists solely to provide
     compatibility support between Python 2 and Python 3 code, is now
     deprecated.  Its removal is currently unplanned, but users are
     encouraged to use *note str: 44f. instead wherever possible.
     (Contributed by Alex Waygood in gh-92332(8).)

   * The keyword argument syntax for constructing *note
     typing.TypedDict: 162. types is now deprecated.  Support will be
     removed in Python 3.13.  (Contributed by Jingchen Ye in
     gh-90224(9).)

   * ‘webbrowser.MacOSX’ is deprecated and will be removed in Python
     3.13.  It is untested, undocumented, and not used by *note
     webbrowser: 115. itself.  (Contributed by Donghee Na in
     bpo-42255(10).)

   * The behavior of returning a value from a *note TestCase: 451. and
     *note IsolatedAsyncioTestCase: 30c. test methods (other than the
     default ‘None’ value) is now deprecated.

   * Deprecated the following not-formally-documented *note unittest:
     106. functions, scheduled for removal in Python 3.13:

        * ‘unittest.findTestCases()’

        * ‘unittest.makeSuite()’

        * ‘unittest.getTestCaseNames()’

     Use *note TestLoader: 28e. methods instead:

        * *note unittest.TestLoader.loadTestsFromModule(): 28f.

        * *note unittest.TestLoader.loadTestsFromTestCase(): 290.

        * *note unittest.TestLoader.getTestCaseNames(): 291.

     (Contributed by Erlend E. Aasland in bpo-5846(11).)

   * ‘unittest.TestProgram.usageExit()’ is marked deprecated, to be
     removed in 3.13.  (Contributed by Carlos Damázio in gh-67048(12).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45173

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46607

   (3) https://github.com/python/cpython/issues/90817

   (4) https://github.com/python/cpython/issues/90817

   (5) https://github.com/python/cpython/issues/91760

   (6) https://github.com/python/cpython/issues/92728

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45837

   (8) https://github.com/python/cpython/issues/92332

   (9) https://github.com/python/cpython/issues/90224

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42255

   (11) https://bugs.python.org/issue?@action=redirect&bpo=5846

   (12) https://github.com/python/cpython/issues/67048


File: python.info,  Node: Pending Removal in Python 3 12,  Next: Removed<3>,  Prev: Deprecated<3>,  Up: What’s New In Python 3 11

1.3.12 Pending Removal in Python 3.12
-------------------------------------

The following Python APIs have been deprecated in earlier Python
releases, and will be removed in Python 3.12.

C APIs pending removal are *note listed separately: 72c.

   * The ‘asynchat’ module

   * The ‘asyncore’ module

   * The *note entire distutils package: 72d.

   * The ‘imp’ module

   * The *note typing.io: 72e. namespace

   * The *note typing.re: 72f. namespace

   * ‘cgi.log()’

   * ‘importlib.find_loader()’

   * ‘importlib.abc.Loader.module_repr()’

   * ‘importlib.abc.MetaPathFinder.find_module()’

   * ‘importlib.abc.PathEntryFinder.find_loader()’

   * ‘importlib.abc.PathEntryFinder.find_module()’

   * ‘importlib.machinery.BuiltinImporter.find_module()’

   * ‘importlib.machinery.BuiltinLoader.module_repr()’

   * ‘importlib.machinery.FileFinder.find_loader()’

   * ‘importlib.machinery.FileFinder.find_module()’

   * ‘importlib.machinery.FrozenImporter.find_module()’

   * ‘importlib.machinery.FrozenLoader.module_repr()’

   * ‘importlib.machinery.PathFinder.find_module()’

   * ‘importlib.machinery.WindowsRegistryFinder.find_module()’

   * ‘importlib.util.module_for_loader()’

   * ‘importlib.util.set_loader_wrapper()’

   * ‘importlib.util.set_package_wrapper()’

   * ‘pkgutil.ImpImporter’

   * ‘pkgutil.ImpLoader’

   * ‘pathlib.Path.link_to()’

   * ‘sqlite3.enable_shared_cache()’

   * ‘sqlite3.OptimizedUnicode()’

   * ‘PYTHONTHREADDEBUG’ environment variable

   * The following deprecated aliases in *note unittest: 106.:

          Deprecated alias                 Method Name                         Deprecated in
                                                                               
          -----------------------------------------------------------------------------------------
                                                                               
          ‘failUnless’                     *note assertTrue(): 52a.            3.1
                                                                               
                                                                               
          ‘failIf’                         *note assertFalse(): 52b.           3.1
                                                                               
                                                                               
          ‘failUnlessEqual’                *note assertEqual(): 52c.           3.1
                                                                               
                                                                               
          ‘failIfEqual’                    *note assertNotEqual(): 52d.        3.1
                                                                               
                                                                               
          ‘failUnlessAlmostEqual’          *note assertAlmostEqual(): 52e.     3.1
                                                                               
                                                                               
          ‘failIfAlmostEqual’              *note assertNotAlmostEqual(): 52f.  3.1
                                                                               
                                                                               
          ‘failUnlessRaises’               *note assertRaises(): 530.          3.1
                                                                               
                                                                               
          ‘assert_’                        *note assertTrue(): 52a.            3.2
                                                                               
                                                                               
          ‘assertEquals’                   *note assertEqual(): 52c.           3.2
                                                                               
                                                                               
          ‘assertNotEquals’                *note assertNotEqual(): 52d.        3.2
                                                                               
                                                                               
          ‘assertAlmostEquals’             *note assertAlmostEqual(): 52e.     3.2
                                                                               
                                                                               
          ‘assertNotAlmostEquals’          *note assertNotAlmostEqual(): 52f.  3.2
                                                                               
                                                                               
          ‘assertRegexpMatches’            *note assertRegex(): 531.           3.2
                                                                               
                                                                               
          ‘assertRaisesRegexp’             *note assertRaisesRegex(): 532.     3.2
                                                                               
                                                                               
          ‘assertNotRegexpMatches’         *note assertNotRegex(): 533.        3.5
                                                                               


File: python.info,  Node: Removed<3>,  Next: Porting to Python 3 11,  Prev: Pending Removal in Python 3 12,  Up: What’s New In Python 3 11

1.3.13 Removed
--------------

This section lists Python APIs that have been removed in Python 3.11.

Removed C APIs are *note listed separately: 733.

   * Removed the ‘@asyncio.coroutine()’ *note decorator: 734. enabling
     legacy generator-based coroutines to be compatible with *note
     async: 735. / *note await: 1b9. code.  The function has been
     deprecated since Python 3.8 and the removal was initially scheduled
     for Python 3.10.  Use *note async def: 5d4. instead.  (Contributed
     by Illia Volochii in bpo-43216(1).)

   * Removed ‘asyncio.coroutines.CoroWrapper’ used for wrapping legacy
     generator-based coroutine objects in the debug mode.  (Contributed
     by Illia Volochii in bpo-43216(2).)

   * Due to significant security concerns, the 'reuse_address' parameter
     of *note asyncio.loop.create_datagram_endpoint(): 736, disabled in
     Python 3.9, is now entirely removed.  This is because of the
     behavior of the socket option ‘SO_REUSEADDR’ in UDP. (Contributed
     by Hugo van Kemenade in bpo-45129(3).)

   * Removed the ‘binhex’ module, deprecated in Python 3.9.  Also
     removed the related, similarly-deprecated *note binascii: 10.
     functions:

        * ‘binascii.a2b_hqx()’

        * ‘binascii.b2a_hqx()’

        * ‘binascii.rlecode_hqx()’

        * ‘binascii.rldecode_hqx()’

     The *note binascii.crc_hqx(): 737. function remains available.

     (Contributed by Victor Stinner in bpo-45085(4).)

   * Removed the ‘distutils’ ‘bdist_msi’ command deprecated in Python
     3.9.  Use ‘bdist_wheel’ (wheel packages) instead.  (Contributed by
     Hugo van Kemenade in bpo-45124(5).)

   * Removed the *note __getitem__(): 283. methods of *note
     xml.dom.pulldom.DOMEventStream: 738, *note
     wsgiref.util.FileWrapper: 739. and *note fileinput.FileInput: 73a,
     deprecated since Python 3.9.  (Contributed by Hugo van Kemenade in
     bpo-45132(6).)

   * Removed the deprecated *note gettext: 63. functions ‘lgettext()’,
     ‘ldgettext()’, ‘lngettext()’ and ‘ldngettext()’.  Also removed the
     ‘bind_textdomain_codeset()’ function, the
     ‘NullTranslations.output_charset()’ and
     ‘NullTranslations.set_output_charset()’ methods, and the 'codeset'
     parameter of ‘translation()’ and ‘install()’, since they are only
     used for the ‘l*gettext()’ functions.  (Contributed by Donghee Na
     and Serhiy Storchaka in bpo-44235(7).)

   * Removed from the *note inspect: 7e. module:

        * The ‘getargspec()’ function, deprecated since Python 3.0; use
          *note inspect.signature(): 73b. or *note
          inspect.getfullargspec(): 73c. instead.

        * The ‘formatargspec()’ function, deprecated since Python 3.5;
          use the *note inspect.signature(): 73b. function or the *note
          inspect.Signature: 1cf. object directly.

        * The undocumented ‘Signature.from_builtin()’ and
          ‘Signature.from_function()’ methods, deprecated since Python
          3.5; use the *note Signature.from_callable(): 73d. method
          instead.

     (Contributed by Hugo van Kemenade in bpo-45320(8).)

   * Removed the *note __class_getitem__(): 73e. method from *note
     pathlib.PurePath: 4a9, because it was not used and added by mistake
     in previous versions.  (Contributed by Nikita Sobolev in
     bpo-46483(9).)

   * Removed the ‘MailmanProxy’ class in the ‘smtpd’ module, as it is
     unusable without the external ‘mailman’ package.  (Contributed by
     Donghee Na in bpo-35800(10).)

   * Removed the deprecated ‘split()’ method of ‘_tkinter.TkappType’.
     (Contributed by Erlend E. Aasland in bpo-38371(11).)

   * Removed namespace package support from *note unittest: 106.
     discovery.  It was introduced in Python 3.4 but has been broken
     since Python 3.7.  (Contributed by Inada Naoki in bpo-23882(12).)

   * Removed the undocumented private ‘float.__set_format__()’ method,
     previously known as ‘float.__setformat__()’ in Python 3.7.  Its
     docstring said: “You probably don’t want to use this function.  It
     exists mainly to be used in Python’s test suite.” (Contributed by
     Victor Stinner in bpo-46852(13).)

   * The ‘--experimental-isolated-subinterpreters’ configure flag (and
     corresponding ‘EXPERIMENTAL_ISOLATED_SUBINTERPRETERS’ macro) have
     been removed.

   * Pynche(14) — The Pythonically Natural Color and Hue Editor — has
     been moved out of ‘Tools/scripts’ and is being developed
     independently(15) from the Python source tree.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43216

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43216

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45129

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45085

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45124

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45132

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44235

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45320

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46483

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35800

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38371

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23882

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46852

   (14) https://pypi.org/project/Pynche/

   (15) https://gitlab.com/warsaw/pynche/-/tree/main


File: python.info,  Node: Porting to Python 3 11,  Next: Build Changes<3>,  Prev: Removed<3>,  Up: What’s New In Python 3 11

1.3.14 Porting to Python 3.11
-----------------------------

This section lists previously described changes and other bugfixes in
the Python API that may require changes to your Python code.

Porting notes for the C API are *note listed separately: 742.

   * *note open(): 51f, *note io.open(): 520, *note codecs.open(): 743.
     and *note fileinput.FileInput: 73a. no longer accept ‘'U'’
     (“universal newline”) in the file mode.  In Python 3, “universal
     newline” mode is used by default whenever a file is opened in text
     mode, and the ‘'U'’ flag has been deprecated since Python 3.3.  The
     *note newline parameter: 744. to these functions controls how
     universal newlines work.  (Contributed by Victor Stinner in
     bpo-37330(1).)

   * *note ast.AST: 1a6. node positions are now validated when provided
     to *note compile(): 192. and other related functions.  If invalid
     positions are detected, a *note ValueError: 202. will be raised.
     (Contributed by Pablo Galindo in gh-93351(2))

   * Prohibited passing non-*note concurrent.futures.ThreadPoolExecutor:
     745. executors to *note asyncio.loop.set_default_executor(): 746.
     following a deprecation in Python 3.8.  (Contributed by Illia
     Volochii in bpo-43234(3).)

   * *note calendar: 14.: The *note calendar.LocaleTextCalendar: 747.
     and *note calendar.LocaleHTMLCalendar: 748. classes now use *note
     locale.getlocale(): 2da, instead of using *note
     locale.getdefaultlocale(): 2d9, if no locale is specified.
     (Contributed by Victor Stinner in bpo-46659(4).)

   * The *note pdb: a5. module now reads the ‘.pdbrc’ configuration file
     with the ‘'UTF-8'’ encoding.  (Contributed by Srinivas Reddy
     Thatiparthy (శ్రీనివాస్ రెడ్డి తాటిపర్తి) in bpo-41137(5).)

   * The 'population' parameter of *note random.sample(): 749. must be a
     sequence, and automatic conversion of *note set: 5dc.s to *note
     list: 614.s is no longer supported.  Also, if the sample size is
     larger than the population size, a *note ValueError: 202. is
     raised.  (Contributed by Raymond Hettinger in bpo-40465(6).)

   * The 'random' optional parameter of *note random.shuffle(): 74a. was
     removed.  It was previously an arbitrary random function to use for
     the shuffle; now, *note random.random(): 74b. (its previous
     default) will always be used.

   * In *note re: b9. *note Regular Expression Syntax: 727, global
     inline flags (e.g.  ‘(?i)’) can now only be used at the start of
     regular expressions.  Using them elsewhere has been deprecated
     since Python 3.6.  (Contributed by Serhiy Storchaka in
     bpo-47066(7).)

   * In the *note re: b9. module, several long-standing bugs where fixed
     that, in rare cases, could cause capture groups to get the wrong
     result.  Therefore, this could change the captured output in these
     cases.  (Contributed by Ma Lin in bpo-35859(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37330

   (2) https://github.com/python/cpython/issues/93351

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43234

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46659

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41137

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40465

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47066

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35859


File: python.info,  Node: Build Changes<3>,  Next: C API Changes<3>,  Prev: Porting to Python 3 11,  Up: What’s New In Python 3 11

1.3.15 Build Changes
--------------------

   * CPython now has PEP 11(1) Tier 3 support(2) for cross compiling to
     the WebAssembly(3) platforms Emscripten(4)
     (‘wasm32-unknown-emscripten’, i.e.  Python in the browser) and
     WebAssembly System Interface (WASI)(5) (‘wasm32-unknown-wasi’).
     The effort is inspired by previous work like Pyodide(6).  These
     platforms provide a limited subset of POSIX APIs; Python standard
     libraries features and modules related to networking, processes,
     threading, signals, mmap, and users/groups are not available or
     don’t work.  (Emscripten contributed by Christian Heimes and Ethan
     Smith in gh-84461(7) and WASI contributed by Christian Heimes in
     gh-90473(8); platforms promoted in gh-95085(9))

   * Building CPython now requires:

        * A C11(10) compiler and standard library.  Optional C11
          features(11) are not required.  (Contributed by Victor Stinner
          in bpo-46656(12), bpo-45440(13) and bpo-46640(14).)

        * Support for IEEE 754(15) floating-point numbers.  (Contributed
          by Victor Stinner in bpo-46917(16).)

   * The ‘Py_NO_NAN’ macro has been removed.  Since CPython now requires
     IEEE 754 floats, NaN values are always available.  (Contributed by
     Victor Stinner in bpo-46656(17).)

   * The *note tkinter: f0. package now requires Tcl/Tk(18) version
     8.5.12 or newer.  (Contributed by Serhiy Storchaka in
     bpo-46996(19).)

   * Build dependencies, compiler flags, and linker flags for most
     stdlib extension modules are now detected by ‘configure’.  libffi,
     libnsl, libsqlite3, zlib, bzip2, liblzma, libcrypt, Tcl/Tk, and
     uuid flags are detected by pkg-config(20) (when available).  *note
     tkinter: f0. now requires a pkg-config command to detect
     development settings for Tcl/Tk(21) headers and libraries.
     (Contributed by Christian Heimes and Erlend Egeberg Aasland in
     bpo-45847(22), bpo-45747(23), and bpo-45763(24).)

   * libpython is no longer linked against libcrypt.  (Contributed by
     Mike Gilbert in bpo-45433(25).)

   * CPython can now be built with the ThinLTO(26) option via passing
     ‘thin’ to *note -with-lto: 74e, i.e.  ‘--with-lto=thin’.
     (Contributed by Donghee Na and Brett Holman in bpo-44340(27).)

   * Freelists for object structs can now be disabled.  A new
     ‘configure’ option *note -without-freelists: 74f. can be used to
     disable all freelists except empty tuple singleton.  (Contributed
     by Christian Heimes in bpo-45522(28).)

   * ‘Modules/Setup’ and ‘Modules/makesetup’ have been improved and tied
     up.  Extension modules can now be built through ‘makesetup’.  All
     except some test modules can be linked statically into a main
     binary or library.  (Contributed by Brett Cannon and Christian
     Heimes in bpo-45548(29), bpo-45570(30), bpo-45571(31), and
     bpo-43974(32).)

          Note: Use the environment variables ‘TCLTK_CFLAGS’ and
          ‘TCLTK_LIBS’ to manually specify the location of Tcl/Tk
          headers and libraries.  The ‘configure’ options
          ‘--with-tcltk-includes’ and ‘--with-tcltk-libs’ have been
          removed.

          On RHEL 7 and CentOS 7 the development packages do not provide
          ‘tcl.pc’ and ‘tk.pc’; use ‘TCLTK_LIBS="-ltk8.5 -ltkstub8.5
          -ltcl8.5"’.  The directory ‘Misc/rhel7’ contains ‘.pc’ files
          and instructions on how to build Python with RHEL 7’s and
          CentOS 7’s Tcl/Tk and OpenSSL.

   * CPython will now use 30-bit digits by default for the Python *note
     int: 257. implementation.  Previously, the default was to use
     30-bit digits on platforms with ‘SIZEOF_VOID_P >= 8’, and 15-bit
     digits otherwise.  It’s still possible to explicitly request use of
     15-bit digits via either the *note -enable-big-digits: 750. option
     to the configure script or (for Windows) the ‘PYLONG_BITS_IN_DIGIT’
     variable in ‘PC/pyconfig.h’, but this option may be removed at some
     point in the future.  (Contributed by Mark Dickinson in
     bpo-45569(33).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0011/

   (2) https://peps.python.org/pep-0011/#tier-3

   (3) https://webassembly.org/

   (4) https://emscripten.org/

   (5) https://wasi.dev/

   (6) https://pyodide.org/

   (7) https://github.com/python/cpython/issues/84461

   (8) https://github.com/python/cpython/issues/90473

   (9) https://github.com/python/cpython/issues/95085

   (10) https://en.cppreference.com/w/c/11

   (11) 
https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features

   (12) https://bugs.python.org/issue?@action=redirect&bpo=46656

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45440

   (14) https://bugs.python.org/issue?@action=redirect&bpo=46640

   (15) https://en.wikipedia.org/wiki/IEEE_754

   (16) https://bugs.python.org/issue?@action=redirect&bpo=46917

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46656

   (18) https://www.tcl.tk

   (19) https://bugs.python.org/issue?@action=redirect&bpo=46996

   (20) https://www.freedesktop.org/wiki/Software/pkg-config/

   (21) https://www.tcl.tk

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45847

   (23) https://bugs.python.org/issue?@action=redirect&bpo=45747

   (24) https://bugs.python.org/issue?@action=redirect&bpo=45763

   (25) https://bugs.python.org/issue?@action=redirect&bpo=45433

   (26) https://clang.llvm.org/docs/ThinLTO.html

   (27) https://bugs.python.org/issue?@action=redirect&bpo=44340

   (28) https://bugs.python.org/issue?@action=redirect&bpo=45522

   (29) https://bugs.python.org/issue?@action=redirect&bpo=45548

   (30) https://bugs.python.org/issue?@action=redirect&bpo=45570

   (31) https://bugs.python.org/issue?@action=redirect&bpo=45571

   (32) https://bugs.python.org/issue?@action=redirect&bpo=43974

   (33) https://bugs.python.org/issue?@action=redirect&bpo=45569


File: python.info,  Node: C API Changes<3>,  Next: Notable changes in 3 11 4,  Prev: Build Changes<3>,  Up: What’s New In Python 3 11

1.3.16 C API Changes
--------------------

* Menu:

* New Features: New Features<6>.
* Porting to Python 3.11: Porting to Python 3 11<2>.
* Deprecated: Deprecated<4>.
* Pending Removal in Python 3.12: Pending Removal in Python 3 12<2>.
* Removed: Removed<4>.


File: python.info,  Node: New Features<6>,  Next: Porting to Python 3 11<2>,  Up: C API Changes<3>

1.3.16.1 New Features
.....................

   * Add a new *note PyType_GetName(): 755. function to get type’s short
     name.  (Contributed by Hai Shi in bpo-42035(1).)

   * Add a new *note PyType_GetQualName(): 756. function to get type’s
     qualified name.  (Contributed by Hai Shi in bpo-42035(2).)

   * Add new *note PyThreadState_EnterTracing(): 757. and *note
     PyThreadState_LeaveTracing(): 758. functions to the limited C API
     to suspend and resume tracing and profiling.  (Contributed by
     Victor Stinner in bpo-43760(3).)

   * Added the *note Py_Version: 759. constant which bears the same
     value as *note PY_VERSION_HEX: 75a.  (Contributed by Gabriele N.
     Tornetta in bpo-43931(4).)

   * *note Py_buffer: 75b. and APIs are now part of the limited API and
     the stable ABI:

        * *note PyObject_CheckBuffer(): 39b.

        * *note PyObject_GetBuffer(): 39c.

        * *note PyBuffer_GetPointer(): 75c.

        * *note PyBuffer_SizeFromFormat(): 75d.

        * *note PyBuffer_ToContiguous(): 75e.

        * *note PyBuffer_FromContiguous(): 75f.

        * *note PyObject_CopyData(): 760.

        * *note PyBuffer_IsContiguous(): 761.

        * *note PyBuffer_FillContiguousStrides(): 762.

        * *note PyBuffer_FillInfo(): 763.

        * *note PyBuffer_Release(): 39d.

        * *note PyMemoryView_FromBuffer(): 764.

        * *note bf_getbuffer: 765. and *note bf_releasebuffer: 766. type
          slots

     (Contributed by Christian Heimes in bpo-45459(5).)

   * Added the *note PyType_GetModuleByDef(): 397. function, used to get
     the module in which a method was defined, in cases where this
     information is not available directly (via *note PyCMethod: 767.).
     (Contributed by Petr Viktorin in bpo-46613(6).)

   * Add new functions to pack and unpack C double (serialize and
     deserialize): *note PyFloat_Pack2(): 768, *note PyFloat_Pack4():
     769, *note PyFloat_Pack8(): 76a, *note PyFloat_Unpack2(): 76b,
     *note PyFloat_Unpack4(): 76c. and *note PyFloat_Unpack8(): 76d.
     (Contributed by Victor Stinner in bpo-46906(7).)

   * Add new functions to get frame object attributes: *note
     PyFrame_GetBuiltins(): 76e, *note PyFrame_GetGenerator(): 76f,
     *note PyFrame_GetGlobals(): 770, *note PyFrame_GetLasti(): 771.

   * Added two new functions to get and set the active exception
     instance: *note PyErr_GetHandledException(): 772. and *note
     PyErr_SetHandledException(): 773.  These are alternatives to *note
     PyErr_SetExcInfo(): 774. and *note PyErr_GetExcInfo(): 775. which
     work with the legacy 3-tuple representation of exceptions.
     (Contributed by Irit Katriel in bpo-46343(8).)

   * Added the *note PyConfig.safe_path: 776. member.  (Contributed by
     Victor Stinner in gh-57684(9).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42035

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42035

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43760

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43931

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45459

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46613

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46906

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46343

   (9) https://github.com/python/cpython/issues/57684


File: python.info,  Node: Porting to Python 3 11<2>,  Next: Deprecated<4>,  Prev: New Features<6>,  Up: C API Changes<3>

1.3.16.2 Porting to Python 3.11
...............................

   * Some macros have been converted to static inline functions to avoid
     macro pitfalls(1).  The change should be mostly transparent to
     users, as the replacement functions will cast their arguments to
     the expected types to avoid compiler warnings due to static type
     checks.  However, when the limited C API is set to >=3.11, these
     casts are not done, and callers will need to cast arguments to
     their expected types.  See PEP 670(2) for more details.
     (Contributed by Victor Stinner and Erlend E. Aasland in
     gh-89653(3).)

   * *note PyErr_SetExcInfo(): 774. no longer uses the ‘type’ and
     ‘traceback’ arguments, the interpreter now derives those values
     from the exception instance (the ‘value’ argument).  The function
     still steals references of all three arguments.  (Contributed by
     Irit Katriel in bpo-45711(4).)

   * *note PyErr_GetExcInfo(): 775. now derives the ‘type’ and
     ‘traceback’ fields of the result from the exception instance (the
     ‘value’ field).  (Contributed by Irit Katriel in bpo-45711(5).)

   * *note _frozen: 778. has a new ‘is_package’ field to indicate
     whether or not the frozen module is a package.  Previously, a
     negative value in the ‘size’ field was the indicator.  Now only
     non-negative values be used for ‘size’.  (Contributed by Kumar
     Aditya in bpo-46608(6).)

   * *note _PyFrameEvalFunction(): 779. now takes ‘_PyInterpreterFrame*’
     as its second parameter, instead of ‘PyFrameObject*’.  See PEP
     523(7) for more details of how to use this function pointer type.

   * ‘PyCode_New()’ and ‘PyCode_NewWithPosOnlyArgs()’ now take an
     additional ‘exception_table’ argument.  Using these functions
     should be avoided, if at all possible.  To get a custom code
     object: create a code object using the compiler, then get a
     modified version with the ‘replace’ method.

   * *note PyCodeObject: 77a. no longer has the ‘co_code’,
     ‘co_varnames’, ‘co_cellvars’ and ‘co_freevars’ fields.  Instead,
     use *note PyCode_GetCode(): 77b, *note PyCode_GetVarnames(): 77c,
     *note PyCode_GetCellvars(): 77d. and *note PyCode_GetFreevars():
     77e. respectively to access them via the C API. (Contributed by
     Brandt Bucher in bpo-46841(8) and Ken Jin in gh-92154(9) and
     gh-94936(10).)

   * The old trashcan macros
     (‘Py_TRASHCAN_SAFE_BEGIN’/‘Py_TRASHCAN_SAFE_END’) are now
     deprecated.  They should be replaced by the new macros
     ‘Py_TRASHCAN_BEGIN’ and ‘Py_TRASHCAN_END’.

     A tp_dealloc function that has the old macros, such as:

          static void
          mytype_dealloc(mytype *p)
          {
              PyObject_GC_UnTrack(p);
              Py_TRASHCAN_SAFE_BEGIN(p);
              ...
              Py_TRASHCAN_SAFE_END
          }

     should migrate to the new macros as follows:

          static void
          mytype_dealloc(mytype *p)
          {
              PyObject_GC_UnTrack(p);
              Py_TRASHCAN_BEGIN(p, mytype_dealloc)
              ...
              Py_TRASHCAN_END
          }

     Note that ‘Py_TRASHCAN_BEGIN’ has a second argument which should be
     the deallocation function it is in.

     To support older Python versions in the same codebase, you can
     define the following macros and use them throughout the code
     (credit: these were copied from the ‘mypy’ codebase):

          #if PY_VERSION_HEX >= 0x03080000
          #  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_BEGIN(op, dealloc)
          #  define CPy_TRASHCAN_END(op) Py_TRASHCAN_END
          #else
          #  define CPy_TRASHCAN_BEGIN(op, dealloc) Py_TRASHCAN_SAFE_BEGIN(op)
          #  define CPy_TRASHCAN_END(op) Py_TRASHCAN_SAFE_END(op)
          #endif

   * The *note PyType_Ready(): 77f. function now raises an error if a
     type is defined with the *note Py_TPFLAGS_HAVE_GC: 780. flag set
     but has no traverse function (*note PyTypeObject.tp_traverse:
     781.).  (Contributed by Victor Stinner in bpo-44263(11).)

   * Heap types with the *note Py_TPFLAGS_IMMUTABLETYPE: 3c5. flag can
     now inherit the PEP 590(12) vectorcall protocol.  Previously, this
     was only possible for *note static types: 782.  (Contributed by
     Erlend E. Aasland in bpo-43908(13))

   * Since *note Py_TYPE(): 783. is changed to a inline static function,
     ‘Py_TYPE(obj) = new_type’ must be replaced with ‘Py_SET_TYPE(obj,
     new_type)’: see the *note Py_SET_TYPE(): 784. function (available
     since Python 3.9).  For backward compatibility, this macro can be
     used:

          #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_TYPE)
          static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type)
          { ob->ob_type = type; }
          #define Py_SET_TYPE(ob, type) _Py_SET_TYPE((PyObject*)(ob), type)
          #endif

     (Contributed by Victor Stinner in bpo-39573(14).)

   * Since *note Py_SIZE(): 785. is changed to a inline static function,
     ‘Py_SIZE(obj) = new_size’ must be replaced with ‘Py_SET_SIZE(obj,
     new_size)’: see the *note Py_SET_SIZE(): 786. function (available
     since Python 3.9).  For backward compatibility, this macro can be
     used:

          #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_SIZE)
          static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size)
          { ob->ob_size = size; }
          #define Py_SET_SIZE(ob, size) _Py_SET_SIZE((PyVarObject*)(ob), size)
          #endif

     (Contributed by Victor Stinner in bpo-39573(15).)

   * ‘<Python.h>’ no longer includes the header files ‘<stdlib.h>’,
     ‘<stdio.h>’, ‘<errno.h>’ and ‘<string.h>’ when the ‘Py_LIMITED_API’
     macro is set to ‘0x030b0000’ (Python 3.11) or higher.  C extensions
     should explicitly include the header files after ‘#include
     <Python.h>’.  (Contributed by Victor Stinner in bpo-45434(16).)

   * The non-limited API files ‘cellobject.h’, ‘classobject.h’,
     ‘code.h’, ‘context.h’, ‘funcobject.h’, ‘genobject.h’ and
     ‘longintrepr.h’ have been moved to the ‘Include/cpython’ directory.
     Moreover, the ‘eval.h’ header file was removed.  These files must
     not be included directly, as they are already included in
     ‘Python.h’: *note Include Files: 787.  If they have been included
     directly, consider including ‘Python.h’ instead.  (Contributed by
     Victor Stinner in bpo-35134(17).)

   * The ‘PyUnicode_CHECK_INTERNED()’ macro has been excluded from the
     limited C API. It was never usable there, because it used internal
     structures which are not available in the limited C API.
     (Contributed by Victor Stinner in bpo-46007(18).)

   * The following frame functions and type are now directly available
     with ‘#include <Python.h>’, it’s no longer needed to add ‘#include
     <frameobject.h>’:

        * *note PyFrame_Check(): 788.

        * *note PyFrame_GetBack(): 789.

        * *note PyFrame_GetBuiltins(): 76e.

        * *note PyFrame_GetGenerator(): 76f.

        * *note PyFrame_GetGlobals(): 770.

        * *note PyFrame_GetLasti(): 771.

        * *note PyFrame_GetLocals(): 422.

        * *note PyFrame_Type: 78a.

     (Contributed by Victor Stinner in gh-93937(19).)

   * The *note PyFrameObject: 78c. structure members have been removed
     from the public C API.

     While the documentation notes that the *note PyFrameObject: 78c.
     fields are subject to change at any time, they have been stable for
     a long time and were used in several popular extensions.

     In Python 3.11, the frame struct was reorganized to allow
     performance optimizations.  Some fields were removed entirely, as
     they were details of the old implementation.

     *note PyFrameObject: 78c. fields:

        * ‘f_back’: use *note PyFrame_GetBack(): 789.

        * ‘f_blockstack’: removed.

        * ‘f_builtins’: use *note PyFrame_GetBuiltins(): 76e.

        * ‘f_code’: use *note PyFrame_GetCode(): 78d.

        * ‘f_gen’: use *note PyFrame_GetGenerator(): 76f.

        * ‘f_globals’: use *note PyFrame_GetGlobals(): 770.

        * ‘f_iblock’: removed.

        * ‘f_lasti’: use *note PyFrame_GetLasti(): 771.  Code using
          ‘f_lasti’ with ‘PyCode_Addr2Line()’ should use *note
          PyFrame_GetLineNumber(): 78e. instead; it may be faster.

        * ‘f_lineno’: use *note PyFrame_GetLineNumber(): 78e.

        * ‘f_locals’: use *note PyFrame_GetLocals(): 422.

        * ‘f_stackdepth’: removed.

        * ‘f_state’: no public API (renamed to ‘f_frame.f_state’).

        * ‘f_trace’: no public API.

        * ‘f_trace_lines’: use ‘PyObject_GetAttrString((PyObject*)frame,
          "f_trace_lines")’.

        * ‘f_trace_opcodes’: use
          ‘PyObject_GetAttrString((PyObject*)frame, "f_trace_opcodes")’.

        * ‘f_localsplus’: no public API (renamed to
          ‘f_frame.localsplus’).

        * ‘f_valuestack’: removed.

     The Python frame object is now created lazily.  A side effect is
     that the *note f_back: 78f. member must not be accessed directly,
     since its value is now also computed lazily.  The *note
     PyFrame_GetBack(): 789. function must be called instead.

     Debuggers that accessed the *note f_locals: 182. directly 'must'
     call *note PyFrame_GetLocals(): 422. instead.  They no longer need
     to call ‘PyFrame_FastToLocalsWithError()’ or
     ‘PyFrame_LocalsToFast()’, in fact they should not call those
     functions.  The necessary updating of the frame is now managed by
     the virtual machine.

     Code defining ‘PyFrame_GetCode()’ on Python 3.8 and older:

          #if PY_VERSION_HEX < 0x030900B1
          static inline PyCodeObject* PyFrame_GetCode(PyFrameObject *frame)
          {
              Py_INCREF(frame->f_code);
              return frame->f_code;
          }
          #endif

     Code defining ‘PyFrame_GetBack()’ on Python 3.8 and older:

          #if PY_VERSION_HEX < 0x030900B1
          static inline PyFrameObject* PyFrame_GetBack(PyFrameObject *frame)
          {
              Py_XINCREF(frame->f_back);
              return frame->f_back;
          }
          #endif

     Or use the pythoncapi_compat project(20) to get these two functions
     on older Python versions.

   * Changes of the *note PyThreadState: 790. structure members:

        * ‘frame’: removed, use *note PyThreadState_GetFrame(): 791.
          (function added to Python 3.9 by bpo-40429(21)).  Warning: the
          function returns a *note strong reference: 33e, need to call
          *note Py_XDECREF(): 792.

        * ‘tracing’: changed, use *note PyThreadState_EnterTracing():
          757. and *note PyThreadState_LeaveTracing(): 758. (functions
          added to Python 3.11 by bpo-43760(22)).

        * ‘recursion_depth’: removed, use ‘(tstate->recursion_limit -
          tstate->recursion_remaining)’ instead.

        * ‘stackcheck_counter’: removed.

     Code defining ‘PyThreadState_GetFrame()’ on Python 3.8 and older:

          #if PY_VERSION_HEX < 0x030900B1
          static inline PyFrameObject* PyThreadState_GetFrame(PyThreadState *tstate)
          {
              Py_XINCREF(tstate->frame);
              return tstate->frame;
          }
          #endif

     Code defining ‘PyThreadState_EnterTracing()’ and
     ‘PyThreadState_LeaveTracing()’ on Python 3.10 and older:

          #if PY_VERSION_HEX < 0x030B00A2
          static inline void PyThreadState_EnterTracing(PyThreadState *tstate)
          {
              tstate->tracing++;
          #if PY_VERSION_HEX >= 0x030A00A1
              tstate->cframe->use_tracing = 0;
          #else
              tstate->use_tracing = 0;
          #endif
          }

          static inline void PyThreadState_LeaveTracing(PyThreadState *tstate)
          {
              int use_tracing = (tstate->c_tracefunc != NULL || tstate->c_profilefunc != NULL);
              tstate->tracing--;
          #if PY_VERSION_HEX >= 0x030A00A1
              tstate->cframe->use_tracing = use_tracing;
          #else
              tstate->use_tracing = use_tracing;
          #endif
          }
          #endif

     Or use the pythoncapi-compat project(23) to get these functions on
     old Python functions.

   * Distributors are encouraged to build Python with the optimized
     Blake2 library libb2(24).

   * The *note PyConfig.module_search_paths_set: 5f2. field must now be
     set to 1 for initialization to use *note
     PyConfig.module_search_paths: 3a5. to initialize *note sys.path:
     3b7.  Otherwise, initialization will recalculate the path and
     replace any values added to ‘module_search_paths’.

   * *note PyConfig_Read(): 793. no longer calculates the initial search
     path, and will not fill any values into *note
     PyConfig.module_search_paths: 3a5.  To calculate default paths and
     then modify them, finish initialization and use *note
     PySys_GetObject(): 38c. to retrieve *note sys.path: 3b7. as a
     Python list object and modify it directly.

   ---------- Footnotes ----------

   (1) https://gcc.gnu.org/onlinedocs/cpp/Macro-Pitfalls.html

   (2) https://peps.python.org/pep-0670/

   (3) https://github.com/python/cpython/issues/89653

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46608

   (7) https://peps.python.org/pep-0523/

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (9) https://github.com/python/cpython/issues/92154

   (10) https://github.com/python/cpython/issues/94936

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44263

   (12) https://peps.python.org/pep-0590/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43908

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (16) https://bugs.python.org/issue?@action=redirect&bpo=45434

   (17) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (18) https://bugs.python.org/issue?@action=redirect&bpo=46007

   (19) https://github.com/python/cpython/issues/93937

   (20) https://github.com/python/pythoncapi-compat

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40429

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43760

   (23) https://github.com/python/pythoncapi-compat

   (24) https://www.blake2.net/


File: python.info,  Node: Deprecated<4>,  Next: Pending Removal in Python 3 12<2>,  Prev: Porting to Python 3 11<2>,  Up: C API Changes<3>

1.3.16.3 Deprecated
...................

   * Deprecate the following functions to configure the Python
     initialization:

        * ‘PySys_AddWarnOptionUnicode()’

        * ‘PySys_AddWarnOption()’

        * ‘PySys_AddXOption()’

        * ‘PySys_HasWarnOptions()’

        * ‘PySys_SetArgvEx()’

        * ‘PySys_SetArgv()’

        * ‘PySys_SetPath()’

        * ‘Py_SetPath()’

        * ‘Py_SetProgramName()’

        * ‘Py_SetPythonHome()’

        * ‘Py_SetStandardStreamEncoding()’

        * ‘_Py_SetProgramFullPath()’

     Use the new *note PyConfig: 3a9. API of the *note Python
     Initialization Configuration: 3aa. instead ( PEP 587(1)).
     (Contributed by Victor Stinner in gh-88279(2).)

   * Deprecate the ‘ob_shash’ member of the *note PyBytesObject: 795.
     Use *note PyObject_Hash(): 406. instead.  (Contributed by Inada
     Naoki in bpo-46864(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0587/

   (2) https://github.com/python/cpython/issues/88279

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46864


File: python.info,  Node: Pending Removal in Python 3 12<2>,  Next: Removed<4>,  Prev: Deprecated<4>,  Up: C API Changes<3>

1.3.16.4 Pending Removal in Python 3.12
.......................................

The following C APIs have been deprecated in earlier Python releases,
and will be removed in Python 3.12.

   * ‘PyUnicode_AS_DATA()’

   * ‘PyUnicode_AS_UNICODE()’

   * ‘PyUnicode_AsUnicodeAndSize()’

   * ‘PyUnicode_AsUnicode()’

   * ‘PyUnicode_FromUnicode()’

   * ‘PyUnicode_GET_DATA_SIZE()’

   * ‘PyUnicode_GET_SIZE()’

   * ‘PyUnicode_GetSize()’

   * ‘PyUnicode_IS_COMPACT()’

   * ‘PyUnicode_IS_READY()’

   * *note PyUnicode_READY(): 404.

   * ‘PyUnicode_WSTR_LENGTH()’

   * ‘_PyUnicode_AsUnicode()’

   * ‘PyUnicode_WCHAR_KIND’

   * *note PyUnicodeObject: 797.

   * ‘PyUnicode_InternImmortal()’


File: python.info,  Node: Removed<4>,  Prev: Pending Removal in Python 3 12<2>,  Up: C API Changes<3>

1.3.16.5 Removed
................

   * ‘PyFrame_BlockSetup()’ and ‘PyFrame_BlockPop()’ have been removed.
     (Contributed by Mark Shannon in bpo-40222(1).)

   * Remove the following math macros using the ‘errno’ variable:

        * ‘Py_ADJUST_ERANGE1()’

        * ‘Py_ADJUST_ERANGE2()’

        * ‘Py_OVERFLOWED()’

        * ‘Py_SET_ERANGE_IF_OVERFLOW()’

        * ‘Py_SET_ERRNO_ON_MATH_ERROR()’

     (Contributed by Victor Stinner in bpo-45412(2).)

   * Remove ‘Py_UNICODE_COPY()’ and ‘Py_UNICODE_FILL()’ macros,
     deprecated since Python 3.3.  Use ‘PyUnicode_CopyCharacters()’ or
     ‘memcpy()’ (‘wchar_t*’ string), and ‘PyUnicode_Fill()’ functions
     instead.  (Contributed by Victor Stinner in bpo-41123(3).)

   * Remove the ‘pystrhex.h’ header file.  It only contains private
     functions.  C extensions should only include the main ‘<Python.h>’
     header file.  (Contributed by Victor Stinner in bpo-45434(4).)

   * Remove the ‘Py_FORCE_DOUBLE()’ macro.  It was used by the
     ‘Py_IS_INFINITY()’ macro.  (Contributed by Victor Stinner in
     bpo-45440(5).)

   * The following items are no longer available when *note
     Py_LIMITED_API: 421. is defined:

        * *note PyMarshal_WriteLongToFile(): 799.

        * *note PyMarshal_WriteObjectToFile(): 79a.

        * *note PyMarshal_ReadObjectFromString(): 79b.

        * *note PyMarshal_WriteObjectToString(): 79c.

        * the ‘Py_MARSHAL_VERSION’ macro

     These are not part of the *note limited API: 79d.

     (Contributed by Victor Stinner in bpo-45474(6).)

   * Exclude *note PyWeakref_GET_OBJECT(): 3c2. from the limited C API.
     It never worked since the ‘PyWeakReference’ structure is opaque in
     the limited C API. (Contributed by Victor Stinner in bpo-35134(7).)

   * Remove the ‘PyHeapType_GET_MEMBERS()’ macro.  It was exposed in the
     public C API by mistake, it must only be used by Python internally.
     Use the ‘PyTypeObject.tp_members’ member instead.  (Contributed by
     Victor Stinner in bpo-40170(8).)

   * Remove the ‘HAVE_PY_SET_53BIT_PRECISION’ macro (moved to the
     internal C API). (Contributed by Victor Stinner in bpo-45412(9).)

   * Remove the *note Py_UNICODE: 3f0. encoder APIs, as they have been
     deprecated since Python 3.3, are little used and are inefficient
     relative to the recommended alternatives.

     The removed functions are:

        * ‘PyUnicode_Encode()’

        * ‘PyUnicode_EncodeASCII()’

        * ‘PyUnicode_EncodeLatin1()’

        * ‘PyUnicode_EncodeUTF7()’

        * ‘PyUnicode_EncodeUTF8()’

        * ‘PyUnicode_EncodeUTF16()’

        * ‘PyUnicode_EncodeUTF32()’

        * ‘PyUnicode_EncodeUnicodeEscape()’

        * ‘PyUnicode_EncodeRawUnicodeEscape()’

        * ‘PyUnicode_EncodeCharmap()’

        * ‘PyUnicode_TranslateCharmap()’

        * ‘PyUnicode_EncodeDecimal()’

        * ‘PyUnicode_TransformDecimalToASCII()’

     See PEP 624(10) for details and migration guidance(11).
     (Contributed by Inada Naoki in bpo-44029(12).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40222

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45412

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45434

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45440

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45474

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45412

   (10) https://peps.python.org/pep-0624/

   (11) https://peps.python.org/pep-0624/#alternative-apis

   (12) https://bugs.python.org/issue?@action=redirect&bpo=44029


File: python.info,  Node: Notable changes in 3 11 4,  Next: Notable changes in 3 11 5,  Prev: C API Changes<3>,  Up: What’s New In Python 3 11

1.3.17 Notable changes in 3.11.4
--------------------------------

* Menu:

* tarfile: tarfile<2>.


File: python.info,  Node: tarfile<2>,  Up: Notable changes in 3 11 4

1.3.17.1 tarfile
................

   * The extraction methods in *note tarfile: de, and *note
     shutil.unpack_archive(): 46e, have a new a 'filter' argument that
     allows limiting tar features than may be surprising or dangerous,
     such as creating files outside the destination directory.  See
     *note Extraction filters: 46f. for details.  In Python 3.12, use
     without the 'filter' argument will show a *note DeprecationWarning:
     1a5.  In Python 3.14, the default will switch to ‘'data'’.
     (Contributed by Petr Viktorin in PEP 706(1).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0706/


File: python.info,  Node: Notable changes in 3 11 5,  Prev: Notable changes in 3 11 4,  Up: What’s New In Python 3 11

1.3.18 Notable changes in 3.11.5
--------------------------------

* Menu:

* OpenSSL::


File: python.info,  Node: OpenSSL,  Up: Notable changes in 3 11 5

1.3.18.1 OpenSSL
................

   * Windows builds and macOS installers from python.org now use OpenSSL
     3.0.


File: python.info,  Node: What’s New In Python 3 10,  Next: What’s New In Python 3 9,  Prev: What’s New In Python 3 11,  Up: What’s New in Python

1.4 What’s New In Python 3.10
=============================


Editor: Pablo Galindo Salgado

This article explains the new features in Python 3.10, compared to 3.9.
Python 3.10 was released on October 4, 2021.  For full details, see the
*note changelog: 13c.

* Menu:

* Summary – Release highlights: Summary – Release highlights<3>.
* New Features: New Features<7>.
* New Features Related to Type Hints: New Features Related to Type Hints<3>.
* Other Language Changes: Other Language Changes<4>.
* New Modules: New Modules<4>.
* Improved Modules: Improved Modules<4>.
* Optimizations: Optimizations<4>.
* Deprecated: Deprecated<5>.
* Removed: Removed<5>.
* Porting to Python 3.10: Porting to Python 3 10.
* CPython bytecode changes: CPython bytecode changes<3>.
* Build Changes: Build Changes<4>.
* C API Changes: C API Changes<4>.
* Notable security feature in 3.10.7: Notable security feature in 3 10 7.
* Notable security feature in 3.10.8: Notable security feature in 3 10 8.
* Notable changes in 3.10.12: Notable changes in 3 10 12.


File: python.info,  Node: Summary – Release highlights<3>,  Next: New Features<7>,  Up: What’s New In Python 3 10

1.4.1 Summary – Release highlights
----------------------------------

New syntax features:

   * PEP 634(1), Structural Pattern Matching: Specification

   * PEP 635(2), Structural Pattern Matching: Motivation and Rationale

   * PEP 636(3), Structural Pattern Matching: Tutorial

   * bpo-12782(4), Parenthesized context managers are now officially
     allowed.

New features in the standard library:

   * PEP 618(5), Add Optional Length-Checking To zip.

Interpreter improvements:

   * PEP 626(6), Precise line numbers for debugging and other tools.

New typing features:

   * PEP 604(7), Allow writing union types as X | Y

   * PEP 612(8), Parameter Specification Variables

   * PEP 613(9), Explicit Type Aliases

   * PEP 647(10), User-Defined Type Guards

Important deprecations, removals or restrictions:

   * PEP 644(11), Require OpenSSL 1.1.1 or newer

   * PEP 632(12), Deprecate distutils module.

   * PEP 623(13), Deprecate and prepare for the removal of the wstr
     member in PyUnicodeObject.

   * PEP 624(14), Remove Py_UNICODE encoder APIs

   * PEP 597(15), Add optional EncodingWarning

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/

   (2) https://peps.python.org/pep-0635/

   (3) https://peps.python.org/pep-0636/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=12782

   (5) https://peps.python.org/pep-0618/

   (6) https://peps.python.org/pep-0626/

   (7) https://peps.python.org/pep-0604/

   (8) https://peps.python.org/pep-0612/

   (9) https://peps.python.org/pep-0613/

   (10) https://peps.python.org/pep-0647/

   (11) https://peps.python.org/pep-0644/

   (12) https://peps.python.org/pep-0632/

   (13) https://peps.python.org/pep-0623/

   (14) https://peps.python.org/pep-0624/

   (15) https://peps.python.org/pep-0597/


File: python.info,  Node: New Features<7>,  Next: New Features Related to Type Hints<3>,  Prev: Summary – Release highlights<3>,  Up: What’s New In Python 3 10

1.4.2 New Features
------------------

* Menu:

* Parenthesized context managers::
* Better error messages::
* PEP 626; Precise line numbers for debugging and other tools: PEP 626 Precise line numbers for debugging and other tools.
* PEP 634; Structural Pattern Matching: PEP 634 Structural Pattern Matching.
* Optional EncodingWarning and encoding="locale" option::


File: python.info,  Node: Parenthesized context managers,  Next: Better error messages,  Up: New Features<7>

1.4.2.1 Parenthesized context managers
......................................

Using enclosing parentheses for continuation across multiple lines in
context managers is now supported.  This allows formatting a long
collection of context managers in multiple lines in a similar way as it
was previously possible with import statements.  For instance, all these
examples are now valid:

     with (CtxManager() as example):
         ...

     with (
         CtxManager1(),
         CtxManager2()
     ):
         ...

     with (CtxManager1() as example,
           CtxManager2()):
         ...

     with (CtxManager1(),
           CtxManager2() as example):
         ...

     with (
         CtxManager1() as example1,
         CtxManager2() as example2
     ):
         ...

it is also possible to use a trailing comma at the end of the enclosed
group:

     with (
         CtxManager1() as example1,
         CtxManager2() as example2,
         CtxManager3() as example3,
     ):
         ...

This new syntax uses the non LL(1) capacities of the new parser.  Check
PEP 617(1) for more details.

(Contributed by Guido van Rossum, Pablo Galindo and Lysandros Nikolaou
in bpo-12782(2) and bpo-40334(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0617/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12782

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40334


File: python.info,  Node: Better error messages,  Next: PEP 626 Precise line numbers for debugging and other tools,  Prev: Parenthesized context managers,  Up: New Features<7>

1.4.2.2 Better error messages
.............................

* Menu:

* SyntaxErrors::
* IndentationErrors::
* AttributeErrors::
* NameErrors::


File: python.info,  Node: SyntaxErrors,  Next: IndentationErrors,  Up: Better error messages

1.4.2.3 SyntaxErrors
....................

When parsing code that contains unclosed parentheses or brackets the
interpreter now includes the location of the unclosed bracket of
parentheses instead of displaying 'SyntaxError: unexpected EOF while
parsing' or pointing to some incorrect location.  For instance, consider
the following code (notice the unclosed ‘{‘):

     expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
                 38: 4, 39: 4, 45: 5, 46: 5, 47: 5, 48: 5, 49: 5, 54: 6,
     some_other_code = foo()

Previous versions of the interpreter reported confusing places as the
location of the syntax error:

     File "example.py", line 3
         some_other_code = foo()
                         ^
     SyntaxError: invalid syntax

but in Python 3.10 a more informative error is emitted:

     File "example.py", line 1
         expected = {9: 1, 18: 2, 19: 2, 27: 3, 28: 3, 29: 3, 36: 4, 37: 4,
                    ^
     SyntaxError: '{' was never closed

In a similar way, errors involving unclosed string literals (single and
triple quoted) now point to the start of the string instead of reporting
EOF/EOL.

These improvements are inspired by previous work in the PyPy
interpreter.

(Contributed by Pablo Galindo in bpo-42864(1) and Batuhan Taskaya in
bpo-40176(2).)

*note SyntaxError: 18d. exceptions raised by the interpreter will now
highlight the full error range of the expression that constitutes the
syntax error itself, instead of just where the problem is detected.  In
this way, instead of displaying (before Python 3.10):

     >>> foo(x, z for z in range(10), t, w)
       File "<stdin>", line 1
         foo(x, z for z in range(10), t, w)
                ^
     SyntaxError: Generator expression must be parenthesized

now Python 3.10 will display the exception as:

     >>> foo(x, z for z in range(10), t, w)
       File "<stdin>", line 1
         foo(x, z for z in range(10), t, w)
                ^^^^^^^^^^^^^^^^^^^^
     SyntaxError: Generator expression must be parenthesized

This improvement was contributed by Pablo Galindo in bpo-43914(3).

A considerable amount of new specialized messages for *note SyntaxError:
18d. exceptions have been incorporated.  Some of the most notable ones
are as follows:

   * Missing ‘:’ before blocks:

          >>> if rocket.position > event_horizon
            File "<stdin>", line 1
              if rocket.position > event_horizon
                                                ^
          SyntaxError: expected ':'

     (Contributed by Pablo Galindo in bpo-42997(4).)

   * Unparenthesised tuples in comprehensions targets:

          >>> {x,y for x,y in zip('abcd', '1234')}
            File "<stdin>", line 1
              {x,y for x,y in zip('abcd', '1234')}
               ^
          SyntaxError: did you forget parentheses around the comprehension target?

     (Contributed by Pablo Galindo in bpo-43017(5).)

   * Missing commas in collection literals and between expressions:

          >>> items = {
          ... x: 1,
          ... y: 2
          ... z: 3,
            File "<stdin>", line 3
              y: 2
                 ^
          SyntaxError: invalid syntax. Perhaps you forgot a comma?

     (Contributed by Pablo Galindo in bpo-43822(6).)

   * Multiple Exception types without parentheses:

          >>> try:
          ...     build_dyson_sphere()
          ... except NotEnoughScienceError, NotEnoughResourcesError:
            File "<stdin>", line 3
              except NotEnoughScienceError, NotEnoughResourcesError:
                     ^
          SyntaxError: multiple exception types must be parenthesized

     (Contributed by Pablo Galindo in bpo-43149(7).)

   * Missing ‘:’ and values in dictionary literals:

          >>> values = {
          ... x: 1,
          ... y: 2,
          ... z:
          ... }
            File "<stdin>", line 4
              z:
               ^
          SyntaxError: expression expected after dictionary key and ':'

          >>> values = {x:1, y:2, z w:3}
            File "<stdin>", line 1
              values = {x:1, y:2, z w:3}
                                  ^
          SyntaxError: ':' expected after dictionary key

     (Contributed by Pablo Galindo in bpo-43823(8).)

   * ‘try’ blocks without ‘except’ or ‘finally’ blocks:

          >>> try:
          ...     x = 2
          ... something = 3
            File "<stdin>", line 3
              something  = 3
              ^^^^^^^^^
          SyntaxError: expected 'except' or 'finally' block

     (Contributed by Pablo Galindo in bpo-44305(9).)

   * Usage of ‘=’ instead of ‘==’ in comparisons:

          >>> if rocket.position = event_horizon:
            File "<stdin>", line 1
              if rocket.position = event_horizon:
                                 ^
          SyntaxError: cannot assign to attribute here. Maybe you meant '==' instead of '='?

     (Contributed by Pablo Galindo in bpo-43797(10).)

   * Usage of ‘*’ in f-strings:

          >>> f"Black holes {*all_black_holes} and revelations"
            File "<stdin>", line 1
              (*all_black_holes)
               ^
          SyntaxError: f-string: cannot use starred expression here

     (Contributed by Pablo Galindo in bpo-41064(11).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42864

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40176

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43914

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42997

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43017

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43822

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43149

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43823

   (9) https://bugs.python.org/issue?@action=redirect&bpo=44305

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43797

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41064


File: python.info,  Node: IndentationErrors,  Next: AttributeErrors,  Prev: SyntaxErrors,  Up: Better error messages

1.4.2.4 IndentationErrors
.........................

Many *note IndentationError: 7ac. exceptions now have more context
regarding what kind of block was expecting an indentation, including the
location of the statement:

     >>> def foo():
     ...    if lel:
     ...    x = 2
       File "<stdin>", line 3
         x = 2
         ^
     IndentationError: expected an indented block after 'if' statement in line 2


File: python.info,  Node: AttributeErrors,  Next: NameErrors,  Prev: IndentationErrors,  Up: Better error messages

1.4.2.5 AttributeErrors
.......................

When printing *note AttributeError: 34e, ‘PyErr_Display()’ will offer
suggestions of similar attribute names in the object that the exception
was raised from:

     >>> collections.namedtoplo
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     AttributeError: module 'collections' has no attribute 'namedtoplo'. Did you mean: namedtuple?

(Contributed by Pablo Galindo in bpo-38530(1).)

     Warning: Notice this won’t work if ‘PyErr_Display()’ is not called
     to display the error which can happen if some other custom error
     display function is used.  This is a common scenario in some REPLs
     like IPython.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38530


File: python.info,  Node: NameErrors,  Prev: AttributeErrors,  Up: Better error messages

1.4.2.6 NameErrors
..................

When printing *note NameError: 442. raised by the interpreter,
‘PyErr_Display()’ will offer suggestions of similar variable names in
the function that the exception was raised from:

     >>> schwarzschild_black_hole = None
     >>> schwarschild_black_hole
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?

(Contributed by Pablo Galindo in bpo-38530(1).)

     Warning: Notice this won’t work if ‘PyErr_Display()’ is not called
     to display the error, which can happen if some other custom error
     display function is used.  This is a common scenario in some REPLs
     like IPython.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38530


File: python.info,  Node: PEP 626 Precise line numbers for debugging and other tools,  Next: PEP 634 Structural Pattern Matching,  Prev: Better error messages,  Up: New Features<7>

1.4.2.7 PEP 626: Precise line numbers for debugging and other tools
...................................................................

PEP 626 brings more precise and reliable line numbers for debugging,
profiling and coverage tools.  Tracing events, with the correct line
number, are generated for all lines of code executed and only for lines
of code that are executed.

The *note f_lineno: 7b0. attribute of frame objects will always contain
the expected line number.

The *note co_lnotab: 2e0. attribute of *note code objects: 1d2. is
deprecated and will be removed in 3.12.  Code that needs to convert from
offset to line number should use the new *note co_lines(): 2fb. method
instead.


File: python.info,  Node: PEP 634 Structural Pattern Matching,  Next: Optional EncodingWarning and encoding="locale" option,  Prev: PEP 626 Precise line numbers for debugging and other tools,  Up: New Features<7>

1.4.2.8 PEP 634: Structural Pattern Matching
............................................

Structural pattern matching has been added in the form of a 'match
statement' and 'case statements' of patterns with associated actions.
Patterns consist of sequences, mappings, primitive data types as well as
class instances.  Pattern matching enables programs to extract
information from complex data types, branch on the structure of data,
and apply specific actions based on different forms of data.

* Menu:

* Syntax and operations::
* Declarative approach::
* Simple pattern; match to a literal: Simple pattern match to a literal.
* Patterns with a literal and variable::
* Patterns and classes::
* Nested patterns::
* Complex patterns and the wildcard::
* Guard::
* Other Key Features::


File: python.info,  Node: Syntax and operations,  Next: Declarative approach,  Up: PEP 634 Structural Pattern Matching

1.4.2.9 Syntax and operations
.............................

The generic syntax of pattern matching is:

     match subject:
         case <pattern_1>:
             <action_1>
         case <pattern_2>:
             <action_2>
         case <pattern_3>:
             <action_3>
         case _:
             <action_wildcard>

A match statement takes an expression and compares its value to
successive patterns given as one or more case blocks.  Specifically,
pattern matching operates by:

  1. using data with type and shape (the ‘subject’)

  2. evaluating the ‘subject’ in the ‘match’ statement

  3. comparing the subject with each pattern in a ‘case’ statement from
     top to bottom until a match is confirmed.

  4. executing the action associated with the pattern of the confirmed
     match

  5. If an exact match is not confirmed, the last case, a wildcard ‘_’,
     if provided, will be used as the matching case.  If an exact match
     is not confirmed and a wildcard case does not exist, the entire
     match block is a no-op.


File: python.info,  Node: Declarative approach,  Next: Simple pattern match to a literal,  Prev: Syntax and operations,  Up: PEP 634 Structural Pattern Matching

1.4.2.10 Declarative approach
.............................

Readers may be aware of pattern matching through the simple example of
matching a subject (data object) to a literal (pattern) with the switch
statement found in C, Java or JavaScript (and many other languages).
Often the switch statement is used for comparison of an
object/expression with case statements containing literals.

More powerful examples of pattern matching can be found in languages
such as Scala and Elixir.  With structural pattern matching, the
approach is “declarative” and explicitly states the conditions (the
patterns) for data to match.

While an “imperative” series of instructions using nested “if”
statements could be used to accomplish something similar to structural
pattern matching, it is less clear than the “declarative” approach.
Instead the “declarative” approach states the conditions to meet for a
match and is more readable through its explicit patterns.  While
structural pattern matching can be used in its simplest form comparing a
variable to a literal in a case statement, its true value for Python
lies in its handling of the subject’s type and shape.


File: python.info,  Node: Simple pattern match to a literal,  Next: Patterns with a literal and variable,  Prev: Declarative approach,  Up: PEP 634 Structural Pattern Matching

1.4.2.11 Simple pattern: match to a literal
...........................................

Let’s look at this example as pattern matching in its simplest form: a
value, the subject, being matched to several literals, the patterns.  In
the example below, ‘status’ is the subject of the match statement.  The
patterns are each of the case statements, where literals represent
request status codes.  The associated action to the case is executed
after a match:

     def http_error(status):
         match status:
             case 400:
                 return "Bad request"
             case 404:
                 return "Not found"
             case 418:
                 return "I'm a teapot"
             case _:
                 return "Something's wrong with the internet"

If the above function is passed a ‘status’ of 418, “I’m a teapot” is
returned.  If the above function is passed a ‘status’ of 500, the case
statement with ‘_’ will match as a wildcard, and “Something’s wrong with
the internet” is returned.  Note the last block: the variable name, ‘_’,
acts as a 'wildcard' and insures the subject will always match.  The use
of ‘_’ is optional.

You can combine several literals in a single pattern using ‘|’ (“or”):

     case 401 | 403 | 404:
         return "Not allowed"

* Menu:

* Behavior without the wildcard::


File: python.info,  Node: Behavior without the wildcard,  Up: Simple pattern match to a literal

1.4.2.12 Behavior without the wildcard
......................................

If we modify the above example by removing the last case block, the
example becomes:

     def http_error(status):
         match status:
             case 400:
                 return "Bad request"
             case 404:
                 return "Not found"
             case 418:
                 return "I'm a teapot"

Without the use of ‘_’ in a case statement, a match may not exist.  If
no match exists, the behavior is a no-op.  For example, if ‘status’ of
500 is passed, a no-op occurs.


File: python.info,  Node: Patterns with a literal and variable,  Next: Patterns and classes,  Prev: Simple pattern match to a literal,  Up: PEP 634 Structural Pattern Matching

1.4.2.13 Patterns with a literal and variable
.............................................

Patterns can look like unpacking assignments, and a pattern may be used
to bind variables.  In this example, a data point can be unpacked to its
x-coordinate and y-coordinate:

     # point is an (x, y) tuple
     match point:
         case (0, 0):
             print("Origin")
         case (0, y):
             print(f"Y={y}")
         case (x, 0):
             print(f"X={x}")
         case (x, y):
             print(f"X={x}, Y={y}")
         case _:
             raise ValueError("Not a point")

The first pattern has two literals, ‘(0, 0)’, and may be thought of as
an extension of the literal pattern shown above.  The next two patterns
combine a literal and a variable, and the variable 'binds' a value from
the subject (‘point’).  The fourth pattern captures two values, which
makes it conceptually similar to the unpacking assignment ‘(x, y) =
point’.


File: python.info,  Node: Patterns and classes,  Next: Nested patterns,  Prev: Patterns with a literal and variable,  Up: PEP 634 Structural Pattern Matching

1.4.2.14 Patterns and classes
.............................

If you are using classes to structure your data, you can use as a
pattern the class name followed by an argument list resembling a
constructor.  This pattern has the ability to capture instance
attributes into variables:

     class Point:
         def __init__(self, x, y):
             self.x = x
             self.y = y

     def location(point):
         match point:
             case Point(x=0, y=0):
                 print("Origin is the point's location.")
             case Point(x=0, y=y):
                 print(f"Y={y} and the point is on the y-axis.")
             case Point(x=x, y=0):
                 print(f"X={x} and the point is on the x-axis.")
             case Point():
                 print("The point is located somewhere else on the plane.")
             case _:
                 print("Not a point")

* Menu:

* Patterns with positional parameters::


File: python.info,  Node: Patterns with positional parameters,  Up: Patterns and classes

1.4.2.15 Patterns with positional parameters
............................................

You can use positional parameters with some builtin classes that provide
an ordering for their attributes (e.g.  dataclasses).  You can also
define a specific position for attributes in patterns by setting the
‘__match_args__’ special attribute in your classes.  If it’s set to
(“x”, “y”), the following patterns are all equivalent (and all bind the
‘y’ attribute to the ‘var’ variable):

     Point(1, var)
     Point(1, y=var)
     Point(x=1, y=var)
     Point(y=var, x=1)


File: python.info,  Node: Nested patterns,  Next: Complex patterns and the wildcard,  Prev: Patterns and classes,  Up: PEP 634 Structural Pattern Matching

1.4.2.16 Nested patterns
........................

Patterns can be arbitrarily nested.  For example, if our data is a short
list of points, it could be matched like this:

     match points:
         case []:
             print("No points in the list.")
         case [Point(0, 0)]:
             print("The origin is the only point in the list.")
         case [Point(x, y)]:
             print(f"A single point {x}, {y} is in the list.")
         case [Point(0, y1), Point(0, y2)]:
             print(f"Two points on the Y axis at {y1}, {y2} are in the list.")
         case _:
             print("Something else is found in the list.")


File: python.info,  Node: Complex patterns and the wildcard,  Next: Guard,  Prev: Nested patterns,  Up: PEP 634 Structural Pattern Matching

1.4.2.17 Complex patterns and the wildcard
..........................................

To this point, the examples have used ‘_’ alone in the last case
statement.  A wildcard can be used in more complex patterns, such as
‘('error', code, _)’.  For example:

     match test_variable:
         case ('warning', code, 40):
             print("A warning has been received.")
         case ('error', code, _):
             print(f"An error {code} occurred.")

In the above case, ‘test_variable’ will match for (‘error’, code, 100)
and (‘error’, code, 800).


File: python.info,  Node: Guard,  Next: Other Key Features,  Prev: Complex patterns and the wildcard,  Up: PEP 634 Structural Pattern Matching

1.4.2.18 Guard
..............

We can add an ‘if’ clause to a pattern, known as a “guard”.  If the
guard is false, ‘match’ goes on to try the next case block.  Note that
value capture happens before the guard is evaluated:

     match point:
         case Point(x, y) if x == y:
             print(f"The point is located on the diagonal Y=X at {x}.")
         case Point(x, y):
             print(f"Point is not on the diagonal.")


File: python.info,  Node: Other Key Features,  Prev: Guard,  Up: PEP 634 Structural Pattern Matching

1.4.2.19 Other Key Features
...........................

Several other key features:

   - Like unpacking assignments, tuple and list patterns have exactly
     the same meaning and actually match arbitrary sequences.
     Technically, the subject must be a sequence.  Therefore, an
     important exception is that patterns don’t match iterators.  Also,
     to prevent a common mistake, sequence patterns don’t match strings.

   - Sequence patterns support wildcards: ‘[x, y, *rest]’ and ‘(x, y,
     *rest)’ work similar to wildcards in unpacking assignments.  The
     name after ‘*’ may also be ‘_’, so ‘(x, y, *_)’ matches a sequence
     of at least two items without binding the remaining items.

   - Mapping patterns: ‘{"bandwidth": b, "latency": l}’ captures the
     ‘"bandwidth"’ and ‘"latency"’ values from a dict.  Unlike sequence
     patterns, extra keys are ignored.  A wildcard ‘**rest’ is also
     supported.  (But ‘**_’ would be redundant, so is not allowed.)

   - Subpatterns may be captured using the ‘as’ keyword:

          case (Point(x1, y1), Point(x2, y2) as p2): ...

     This binds x1, y1, x2, y2 like you would expect without the ‘as’
     clause, and p2 to the entire second item of the subject.

   - Most literals are compared by equality.  However, the singletons
     ‘True’, ‘False’ and ‘None’ are compared by identity.

   - Named constants may be used in patterns.  These named constants
     must be dotted names to prevent the constant from being interpreted
     as a capture variable:

          from enum import Enum
          class Color(Enum):
              RED = 0
              GREEN = 1
              BLUE = 2

          color = Color.GREEN
          match color:
              case Color.RED:
                  print("I see red!")
              case Color.GREEN:
                  print("Grass is green")
              case Color.BLUE:
                  print("I'm feeling the blues :(")

For the full specification see PEP 634(1).  Motivation and rationale are
in PEP 635(2), and a longer tutorial is in PEP 636(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/

   (2) https://peps.python.org/pep-0635/

   (3) https://peps.python.org/pep-0636/


File: python.info,  Node: Optional EncodingWarning and encoding="locale" option,  Prev: PEP 634 Structural Pattern Matching,  Up: New Features<7>

1.4.2.20 Optional ‘EncodingWarning’ and ‘encoding="locale"’ option
..................................................................

The default encoding of *note TextIOWrapper: 7bf. and *note open(): 51f.
is platform and locale dependent.  Since UTF-8 is used on most Unix
platforms, omitting ‘encoding’ option when opening UTF-8 files (e.g.
JSON, YAML, TOML, Markdown) is a very common bug.  For example:

     # BUG: "rb" mode or encoding="utf-8" should be used.
     with open("data.json") as f:
         data = json.load(f)

To find this type of bug, an optional ‘EncodingWarning’ is added.  It is
emitted when *note sys.flags.warn_default_encoding: 68f. is true and
locale-specific default encoding is used.

‘-X warn_default_encoding’ option and *note PYTHONWARNDEFAULTENCODING:
7c0. are added to enable the warning.

See *note Text Encoding: 7c1. for more information.


File: python.info,  Node: New Features Related to Type Hints<3>,  Next: Other Language Changes<4>,  Prev: New Features<7>,  Up: What’s New In Python 3 10

1.4.3 New Features Related to Type Hints
----------------------------------------

This section covers major changes affecting PEP 484(1) type hints and
the *note typing: 104. module.

* Menu:

* PEP 604; New Type Union Operator: PEP 604 New Type Union Operator.
* PEP 612; Parameter Specification Variables: PEP 612 Parameter Specification Variables.
* PEP 613; TypeAlias: PEP 613 TypeAlias.
* PEP 647; User-Defined Type Guards: PEP 647 User-Defined Type Guards.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: PEP 604 New Type Union Operator,  Next: PEP 612 Parameter Specification Variables,  Up: New Features Related to Type Hints<3>

1.4.3.1 PEP 604: New Type Union Operator
........................................

A new type union operator was introduced which enables the syntax ‘X |
Y’.  This provides a cleaner way of expressing ‘either type X or type Y’
instead of using *note typing.Union: 63e, especially in type hints.

In previous versions of Python, to apply a type hint for functions
accepting arguments of multiple types, *note typing.Union: 63e. was
used:

     def square(number: Union[int, float]) -> Union[int, float]:
         return number ** 2

Type hints can now be written in a more succinct manner:

     def square(number: int | float) -> int | float:
         return number ** 2

This new syntax is also accepted as the second argument to *note
isinstance(): 445. and *note issubclass(): 7c5.:

     >>> isinstance(1, int | str)
     True

See *note Union Type: 7c6. and PEP 604(1) for more details.

(Contributed by Maggie Moss and Philippe Prados in bpo-41428(2), with
additions by Yurii Karabas and Serhiy Storchaka in bpo-44490(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0604/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41428

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44490


File: python.info,  Node: PEP 612 Parameter Specification Variables,  Next: PEP 613 TypeAlias,  Prev: PEP 604 New Type Union Operator,  Up: New Features Related to Type Hints<3>

1.4.3.2 PEP 612: Parameter Specification Variables
..................................................

Two new options to improve the information provided to static type
checkers for PEP 484(1)‘s ‘Callable’ have been added to the *note
typing: 104. module.

The first is the parameter specification variable.  They are used to
forward the parameter types of one callable to another callable – a
pattern commonly found in higher order functions and decorators.
Examples of usage can be found in *note typing.ParamSpec: 15e.
Previously, there was no easy way to type annotate dependency of
parameter types in such a precise manner.

The second option is the new ‘Concatenate’ operator.  It’s used in
conjunction with parameter specification variables to type annotate a
higher order callable which adds or removes parameters of another
callable.  Examples of usage can be found in *note typing.Concatenate:
7c8.

See *note typing.Callable: 7c9, *note typing.ParamSpec: 15e, *note
typing.Concatenate: 7c8, *note typing.ParamSpecArgs: 7ca, *note
typing.ParamSpecKwargs: 7cb, and PEP 612(2) for more details.

(Contributed by Ken Jin in bpo-41559(3), with minor enhancements by
Jelle Zijlstra in bpo-43783(4).  PEP written by Mark Mendoza.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0612/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41559

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43783


File: python.info,  Node: PEP 613 TypeAlias,  Next: PEP 647 User-Defined Type Guards,  Prev: PEP 612 Parameter Specification Variables,  Up: New Features Related to Type Hints<3>

1.4.3.3 PEP 613: TypeAlias
..........................

PEP 484(1) introduced the concept of type aliases, only requiring them
to be top-level unannotated assignments.  This simplicity sometimes made
it difficult for type checkers to distinguish between type aliases and
ordinary assignments, especially when forward references or invalid
types were involved.  Compare:

     StrCache = 'Cache[str]'  # a type alias
     LOG_PREFIX = 'LOG[DEBUG]'  # a module constant

Now the *note typing: 104. module has a special value *note TypeAlias:
7cd. which lets you declare type aliases more explicitly:

     StrCache: TypeAlias = 'Cache[str]'  # a type alias
     LOG_PREFIX = 'LOG[DEBUG]'  # a module constant

See PEP 613(2) for more details.

(Contributed by Mikhail Golubev in bpo-41923(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0613/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41923


File: python.info,  Node: PEP 647 User-Defined Type Guards,  Prev: PEP 613 TypeAlias,  Up: New Features Related to Type Hints<3>

1.4.3.4 PEP 647: User-Defined Type Guards
.........................................

*note TypeGuard: 164. has been added to the *note typing: 104. module to
annotate type guard functions and improve information provided to static
type checkers during type narrowing.  For more information, please see
‘TypeGuard’‘s documentation, and PEP 647(1).

(Contributed by Ken Jin and Guido van Rossum in bpo-43766(2).  PEP
written by Eric Traut.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0647/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43766


File: python.info,  Node: Other Language Changes<4>,  Next: New Modules<4>,  Prev: New Features Related to Type Hints<3>,  Up: What’s New In Python 3 10

1.4.4 Other Language Changes
----------------------------

   * The *note int: 257. type has a new method *note int.bit_count():
     7d0, returning the number of ones in the binary expansion of a
     given integer, also known as the population count.  (Contributed by
     Niklas Fiekas in bpo-29882(1).)

   * The views returned by *note dict.keys(): 7d1, *note dict.values():
     7d2. and *note dict.items(): 7d3. now all have a ‘mapping’
     attribute that gives a *note types.MappingProxyType: 470. object
     wrapping the original dictionary.  (Contributed by Dennis Sweeney
     in bpo-40890(2).)

   * PEP 618(3): The *note zip(): 7d4. function now has an optional
     ‘strict’ flag, used to require that all the iterables have an equal
     length.

   * Builtin and extension functions that take integer arguments no
     longer accept *note Decimal: 29d.s, *note Fraction: 1e7.s and other
     objects that can be converted to integers only with a loss (e.g.
     that have the *note __int__(): 71f. method but do not have the
     *note __index__(): 720. method).  (Contributed by Serhiy Storchaka
     in bpo-37999(4).)

   * If *note object.__ipow__(): 7d5. returns *note NotImplemented: 7d6,
     the operator will correctly fall back to *note object.__pow__():
     7d7. and *note object.__rpow__(): 7d8. as expected.  (Contributed
     by Alex Shkop in bpo-38302(5).)

   * Assignment expressions can now be used unparenthesized within set
     literals and set comprehensions, as well as in sequence indexes
     (but not slices).

   * Functions have a new ‘__builtins__’ attribute which is used to look
     for builtin symbols when a function is executed, instead of looking
     into ‘__globals__['__builtins__']’.  The attribute is initialized
     from ‘__globals__["__builtins__"]’ if it exists, else from the
     current builtins.  (Contributed by Mark Shannon in bpo-42990(6).)

   * Two new builtin functions – *note aiter(): 7d9. and *note anext():
     7da. have been added to provide asynchronous counterparts to *note
     iter(): 7db. and *note next(): 7dc, respectively.  (Contributed by
     Joshua Bronson, Daniel Pope, and Justin Wang in bpo-31861(7).)

   * Static methods (*note @staticmethod: 419.) and class methods (*note
     @classmethod: 166.) now inherit the method attributes
     (‘__module__’, ‘__name__’, ‘__qualname__’, ‘__doc__’,
     ‘__annotations__’) and have a new ‘__wrapped__’ attribute.
     Moreover, static methods are now callable as regular functions.
     (Contributed by Victor Stinner in bpo-43682(8).)

   * Annotations for complex targets (everything beside ‘simple name’
     targets defined by PEP 526(9)) no longer cause any runtime effects
     with ‘from __future__ import annotations’.  (Contributed by Batuhan
     Taskaya in bpo-42737(10).)

   * Class and module objects now lazy-create empty annotations dicts on
     demand.  The annotations dicts are stored in the object’s
     ‘__dict__’ for backwards compatibility.  This improves the best
     practices for working with ‘__annotations__’; for more information,
     please see *note Annotations Best Practices: 7dd.  (Contributed by
     Larry Hastings in bpo-43901(11).)

   * Annotations consist of ‘yield’, ‘yield from’, ‘await’ or named
     expressions are now forbidden under ‘from __future__ import
     annotations’ due to their side effects.  (Contributed by Batuhan
     Taskaya in bpo-42725(12).)

   * Usage of unbound variables, ‘super()’ and other expressions that
     might alter the processing of symbol table as annotations are now
     rendered effectless under ‘from __future__ import annotations’.
     (Contributed by Batuhan Taskaya in bpo-42725(13).)

   * Hashes of NaN values of both *note float: 2f7. type and *note
     decimal.Decimal: 29d. type now depend on object identity.
     Formerly, they always hashed to ‘0’ even though NaN values are not
     equal to one another.  This caused potentially quadratic runtime
     behavior due to excessive hash collisions when creating
     dictionaries and sets containing multiple NaNs.  (Contributed by
     Raymond Hettinger in bpo-43475(14).)

   * A *note SyntaxError: 18d. (instead of a *note NameError: 442.) will
     be raised when deleting the *note __debug__: 7de. constant.
     (Contributed by Donghee Na in bpo-45000(15).)

   * *note SyntaxError: 18d. exceptions now have ‘end_lineno’ and
     ‘end_offset’ attributes.  They will be ‘None’ if not determined.
     (Contributed by Pablo Galindo in bpo-43914(16).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29882

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40890

   (3) https://peps.python.org/pep-0618/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37999

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38302

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42990

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31861

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43682

   (9) https://peps.python.org/pep-0526/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42737

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43901

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42725

   (13) https://bugs.python.org/issue?@action=redirect&bpo=42725

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43475

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45000

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43914


File: python.info,  Node: New Modules<4>,  Next: Improved Modules<4>,  Prev: Other Language Changes<4>,  Up: What’s New In Python 3 10

1.4.5 New Modules
-----------------

   * None.


File: python.info,  Node: Improved Modules<4>,  Next: Optimizations<4>,  Prev: New Modules<4>,  Up: What’s New In Python 3 10

1.4.6 Improved Modules
----------------------

* Menu:

* asyncio: asyncio<4>.
* argparse: argparse<2>.
* array: array<3>.
* asynchat, asyncore, smtpd: asynchat asyncore smtpd.
* base64: base64<2>.
* bdb::
* bisect::
* codecs::
* collections.abc: collections abc.
* contextlib: contextlib<2>.
* curses::
* dataclasses: dataclasses<2>.
* distutils: distutils<2>.
* doctest: doctest<2>.
* encodings::
* enum: enum<4>.
* fileinput::
* faulthandler::
* gc::
* glob: glob<2>.
* hashlib: hashlib<3>.
* hmac::
* IDLE and idlelib: IDLE and idlelib<2>.
* importlib.metadata: importlib metadata<2>.
* inspect: inspect<3>.
* itertools: itertools<3>.
* linecache::
* os: os<4>.
* os.path: os path<4>.
* pathlib: pathlib<5>.
* platform: platform<2>.
* pprint::
* py_compile::
* pyclbr::
* shelve::
* statistics: statistics<3>.
* site: site<2>.
* socket: socket<2>.
* ssl: ssl<3>.
* sqlite3: sqlite3<5>.
* sys: sys<5>.
* _thread::
* threading: threading<3>.
* traceback: traceback<3>.
* types: types<3>.
* typing: typing<5>.
* unittest: unittest<5>.
* urllib.parse: urllib parse.
* xml: xml<2>.
* zipimport: zipimport<3>.


File: python.info,  Node: asyncio<4>,  Next: argparse<2>,  Up: Improved Modules<4>

1.4.6.1 asyncio
...............

Add missing *note connect_accepted_socket(): 7e2. method.  (Contributed
by Alex Grönholm in bpo-41332(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41332


File: python.info,  Node: argparse<2>,  Next: array<3>,  Prev: asyncio<4>,  Up: Improved Modules<4>

1.4.6.2 argparse
................

Misleading phrase “optional arguments” was replaced with “options” in
argparse help.  Some tests might require adaptation if they rely on
exact output match.  (Contributed by Raymond Hettinger in bpo-9694(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9694


File: python.info,  Node: array<3>,  Next: asynchat asyncore smtpd,  Prev: argparse<2>,  Up: Improved Modules<4>

1.4.6.3 array
.............

The *note index(): 7e5. method of *note array.array: 1a0. now has
optional 'start' and 'stop' parameters.  (Contributed by Anders
Lorentsen and Zackery Spytz in bpo-31956(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31956


File: python.info,  Node: asynchat asyncore smtpd,  Next: base64<2>,  Prev: array<3>,  Up: Improved Modules<4>

1.4.6.4 asynchat, asyncore, smtpd
.................................

These modules have been marked as deprecated in their module
documentation since Python 3.6.  An import-time *note
DeprecationWarning: 1a5. has now been added to all three of these
modules.


File: python.info,  Node: base64<2>,  Next: bdb,  Prev: asynchat asyncore smtpd,  Up: Improved Modules<4>

1.4.6.5 base64
..............

Add *note base64.b32hexencode(): 7e8. and *note base64.b32hexdecode():
7e9. to support the Base32 Encoding with Extended Hex Alphabet.


File: python.info,  Node: bdb,  Next: bisect,  Prev: base64<2>,  Up: Improved Modules<4>

1.4.6.6 bdb
...........

Add ‘clearBreakpoints()’ to reset all set breakpoints.  (Contributed by
Irit Katriel in bpo-24160(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24160


File: python.info,  Node: bisect,  Next: codecs,  Prev: bdb,  Up: Improved Modules<4>

1.4.6.7 bisect
..............

Added the possibility of providing a 'key' function to the APIs in the
*note bisect: 11. module.  (Contributed by Raymond Hettinger in
bpo-4356(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4356


File: python.info,  Node: codecs,  Next: collections abc,  Prev: bisect,  Up: Improved Modules<4>

1.4.6.8 codecs
..............

Add a *note codecs.unregister(): 7ed. function to unregister a codec
search function.  (Contributed by Hai Shi in bpo-41842(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41842


File: python.info,  Node: collections abc,  Next: contextlib<2>,  Prev: codecs,  Up: Improved Modules<4>

1.4.6.9 collections.abc
.......................

The ‘__args__’ of the *note parameterized generic: 6b5. for *note
collections.abc.Callable: 7ef. are now consistent with *note
typing.Callable: 7c9.  ‘collections.abc.Callable’ generic now flattens
type parameters, similar to what ‘typing.Callable’ currently does.  This
means that ‘collections.abc.Callable[[int, str], str]’ will have
‘__args__’ of ‘(int, str, str)’; previously this was ‘([int, str],
str)’.  To allow this change, *note types.GenericAlias: 7f0. can now be
subclassed, and a subclass will be returned when subscripting the
‘collections.abc.Callable’ type.  Note that a *note TypeError: 2c3. may
be raised for invalid forms of parameterizing ‘collections.abc.Callable’
which may have passed silently in Python 3.9.  (Contributed by Ken Jin
in bpo-42195(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42195


File: python.info,  Node: contextlib<2>,  Next: curses,  Prev: collections abc,  Up: Improved Modules<4>

1.4.6.10 contextlib
...................

Add a *note contextlib.aclosing(): 7f2. context manager to safely close
async generators and objects representing asynchronously released
resources.  (Contributed by Joongi Kim and John Belmonte in
bpo-41229(1).)

Add asynchronous context manager support to *note
contextlib.nullcontext(): 7f3.  (Contributed by Tom Gringauz in
bpo-41543(2).)

Add *note AsyncContextDecorator: 7f4, for supporting usage of async
context managers as decorators.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41229

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41543


File: python.info,  Node: curses,  Next: dataclasses<2>,  Prev: contextlib<2>,  Up: Improved Modules<4>

1.4.6.11 curses
...............

The extended color functions added in ncurses 6.1 will be used
transparently by *note curses.color_content(): 7f6, *note
curses.init_color(): 7f7, *note curses.init_pair(): 7f8, and *note
curses.pair_content(): 7f9.  A new function, *note
curses.has_extended_color_support(): 7fa, indicates whether extended
color support is provided by the underlying ncurses library.
(Contributed by Jeffrey Kintscher and Hans Petter Jansson in
bpo-36982(1).)

The ‘BUTTON5_*’ constants are now exposed in the *note curses: 2b.
module if they are provided by the underlying curses library.
(Contributed by Zackery Spytz in bpo-39273(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36982

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39273


File: python.info,  Node: dataclasses<2>,  Next: distutils<2>,  Prev: curses,  Up: Improved Modules<4>

1.4.6.12 dataclasses
....................

* Menu:

* __slots__::
* Keyword-only fields::


File: python.info,  Node: __slots__,  Next: Keyword-only fields,  Up: dataclasses<2>

1.4.6.13 __slots__
..................

Added ‘slots’ parameter in *note dataclasses.dataclass(): 1cb.
decorator.  (Contributed by Yurii Karabas in bpo-42269(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42269


File: python.info,  Node: Keyword-only fields,  Prev: __slots__,  Up: dataclasses<2>

1.4.6.14 Keyword-only fields
............................

dataclasses now supports fields that are keyword-only in the generated
__init__ method.  There are a number of ways of specifying keyword-only
fields.

You can say that every field is keyword-only:

     from dataclasses import dataclass

     @dataclass(kw_only=True)
     class Birthday:
         name: str
         birthday: datetime.date

Both ‘name’ and ‘birthday’ are keyword-only parameters to the generated
__init__ method.

You can specify keyword-only on a per-field basis:

     from dataclasses import dataclass, field

     @dataclass
     class Birthday:
         name: str
         birthday: datetime.date = field(kw_only=True)

Here only ‘birthday’ is keyword-only.  If you set ‘kw_only’ on
individual fields, be aware that there are rules about re-ordering
fields due to keyword-only fields needing to follow non-keyword-only
fields.  See the full dataclasses documentation for details.

You can also specify that all fields following a KW_ONLY marker are
keyword-only.  This will probably be the most common usage:

     from dataclasses import dataclass, KW_ONLY

     @dataclass
     class Point:
         x: float
         y: float
         _: KW_ONLY
         z: float = 0.0
         t: float = 0.0

Here, ‘z’ and ‘t’ are keyword-only parameters, while ‘x’ and ‘y’ are
not.  (Contributed by Eric V. Smith in bpo-43532(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43532


File: python.info,  Node: distutils<2>,  Next: doctest<2>,  Prev: dataclasses<2>,  Up: Improved Modules<4>

1.4.6.15 distutils
..................

The entire ‘distutils’ package is deprecated, to be removed in Python
3.12.  Its functionality for specifying package builds has already been
completely replaced by third-party packages ‘setuptools’ and
‘packaging’, and most other commonly used APIs are available elsewhere
in the standard library (such as *note platform: aa, *note shutil: c5,
*note subprocess: d6. or *note sysconfig: db.).  There are no plans to
migrate any other functionality from ‘distutils’, and applications that
are using other functions should plan to make private copies of the
code.  Refer to PEP 632(1) for discussion.

The ‘bdist_wininst’ command deprecated in Python 3.8 has been removed.
The ‘bdist_wheel’ command is now recommended to distribute binary
packages on Windows.  (Contributed by Victor Stinner in bpo-42802(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0632/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42802


File: python.info,  Node: doctest<2>,  Next: encodings,  Prev: distutils<2>,  Up: Improved Modules<4>

1.4.6.16 doctest
................

When a module does not define ‘__loader__’, fall back to
‘__spec__.loader’.  (Contributed by Brett Cannon in bpo-42133(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42133


File: python.info,  Node: encodings,  Next: enum<4>,  Prev: doctest<2>,  Up: Improved Modules<4>

1.4.6.17 encodings
..................

*note encodings.normalize_encoding(): 801. now ignores non-ASCII
characters.  (Contributed by Hai Shi in bpo-39337(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39337


File: python.info,  Node: enum<4>,  Next: fileinput,  Prev: encodings,  Up: Improved Modules<4>

1.4.6.18 enum
.............

*note Enum: 633. *note __repr__(): 61f. now returns
‘enum_name.member_name’ and *note __str__(): 620. now returns
‘member_name’.  Stdlib enums available as module constants have a *note
repr(): 803. of ‘module_name.member_name’.  (Contributed by Ethan Furman
in bpo-40066(1).)

Add *note enum.StrEnum: 61d. for enums where all members are strings.
(Contributed by Ethan Furman in bpo-41816(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40066

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41816


File: python.info,  Node: fileinput,  Next: faulthandler,  Prev: enum<4>,  Up: Improved Modules<4>

1.4.6.19 fileinput
..................

Add 'encoding' and 'errors' parameters in *note fileinput.input(): 805.
and *note fileinput.FileInput: 73a.  (Contributed by Inada Naoki in
bpo-43712(1).)

*note fileinput.hook_compressed(): 806. now returns *note TextIOWrapper:
7bf. object when 'mode' is “r” and file is compressed, like uncompressed
files.  (Contributed by Inada Naoki in bpo-5758(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43712

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5758


File: python.info,  Node: faulthandler,  Next: gc,  Prev: fileinput,  Up: Improved Modules<4>

1.4.6.20 faulthandler
.....................

The *note faulthandler: 58. module now detects if a fatal error occurs
during a garbage collector collection.  (Contributed by Victor Stinner
in bpo-44466(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44466


File: python.info,  Node: gc,  Next: glob<2>,  Prev: faulthandler,  Up: Improved Modules<4>

1.4.6.21 gc
...........

Add audit hooks for *note gc.get_objects(): 809, *note
gc.get_referrers(): 80a. and *note gc.get_referents(): 80b.
(Contributed by Pablo Galindo in bpo-43439(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43439


File: python.info,  Node: glob<2>,  Next: hashlib<3>,  Prev: gc,  Up: Improved Modules<4>

1.4.6.22 glob
.............

Add the 'root_dir' and 'dir_fd' parameters in *note glob(): 29f. and
*note iglob(): 80d. which allow to specify the root directory for
searching.  (Contributed by Serhiy Storchaka in bpo-38144(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38144


File: python.info,  Node: hashlib<3>,  Next: hmac,  Prev: glob<2>,  Up: Improved Modules<4>

1.4.6.23 hashlib
................

The hashlib module requires OpenSSL 1.1.1 or newer.  (Contributed by
Christian Heimes in PEP 644(1) and bpo-43669(2).)

The hashlib module has preliminary support for OpenSSL 3.0.0.
(Contributed by Christian Heimes in bpo-38820(3) and other issues.)

The pure-Python fallback of *note pbkdf2_hmac(): 512. is deprecated.  In
the future PBKDF2-HMAC will only be available when Python has been built
with OpenSSL support.  (Contributed by Christian Heimes in
bpo-43880(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0644/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43669

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38820

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43880


File: python.info,  Node: hmac,  Next: IDLE and idlelib<2>,  Prev: hashlib<3>,  Up: Improved Modules<4>

1.4.6.24 hmac
.............

The hmac module now uses OpenSSL’s HMAC implementation internally.
(Contributed by Christian Heimes in bpo-40645(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40645


File: python.info,  Node: IDLE and idlelib<2>,  Next: importlib metadata<2>,  Prev: hmac,  Up: Improved Modules<4>

1.4.6.25 IDLE and idlelib
.........................

Make IDLE invoke *note sys.excepthook(): 811. (when started without
‘-n’).  User hooks were previously ignored.  (Contributed by Ken Hilton
in bpo-43008(1).)

Rearrange the settings dialog.  Split the General tab into Windows and
Shell/Ed tabs.  Move help sources, which extend the Help menu, to the
Extensions tab.  Make space for new options and shorten the dialog.  The
latter makes the dialog better fit small screens.  (Contributed by Terry
Jan Reedy in bpo-40468(2).)  Move the indent space setting from the Font
tab to the new Windows tab.  (Contributed by Mark Roseman and Terry Jan
Reedy in bpo-33962(3).)

The changes above were backported to a 3.9 maintenance release.

Add a Shell sidebar.  Move the primary prompt (‘>>>’) to the sidebar.
Add secondary prompts (’…’) to the sidebar.  Left click and optional
drag selects one or more lines of text, as with the editor line number
sidebar.  Right click after selecting text lines displays a context menu
with ‘copy with prompts’.  This zips together prompts from the sidebar
with lines from the selected text.  This option also appears on the
context menu for the text.  (Contributed by Tal Einat in bpo-37903(4).)

Use spaces instead of tabs to indent interactive code.  This makes
interactive code entries ‘look right’.  Making this feasible was a major
motivation for adding the shell sidebar.  (Contributed by Terry Jan
Reedy in bpo-37892(5).)

Highlight the new *note soft keywords: 812. *note match: 813, ‘case’,
and *note _: 814. in pattern-matching statements.  However, this
highlighting is not perfect and will be incorrect in some rare cases,
including some ‘_’-s in ‘case’ patterns.  (Contributed by Tal Einat in
bpo-44010(6).)

New in 3.10 maintenance releases.

Apply syntax highlighting to ‘.pyi’ files.  (Contributed by Alex Waygood
and Terry Jan Reedy in bpo-45447(7).)

Include prompts when saving Shell with inputs and outputs.  (Contributed
by Terry Jan Reedy in gh-95191(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43008

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40468

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33962

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37903

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37892

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44010

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45447

   (8) https://github.com/python/cpython/issues/95191


File: python.info,  Node: importlib metadata<2>,  Next: inspect<3>,  Prev: IDLE and idlelib<2>,  Up: Improved Modules<4>

1.4.6.26 importlib.metadata
...........................

Feature parity with ‘importlib_metadata’ 4.6 (history(1)).

*note importlib.metadata entry points: 284. now provide a nicer
experience for selecting entry points by group and name through a new
*note importlib.metadata.EntryPoints: 284. class.  See the Compatibility
Note in the docs for more info on the deprecation and usage.

Added *note importlib.metadata.packages_distributions(): 816. for
resolving top-level Python modules and packages to their *note
importlib.metadata.Distribution: 817.

   ---------- Footnotes ----------

   (1) https://importlib-metadata.readthedocs.io/en/latest/history.html


File: python.info,  Node: inspect<3>,  Next: itertools<3>,  Prev: importlib metadata<2>,  Up: Improved Modules<4>

1.4.6.27 inspect
................

When a module does not define ‘__loader__’, fall back to
‘__spec__.loader’.  (Contributed by Brett Cannon in bpo-42133(1).)

Add *note inspect.get_annotations(): 819, which safely computes the
annotations defined on an object.  It works around the quirks of
accessing the annotations on various types of objects, and makes very
few assumptions about the object it examines.
‘inspect.get_annotations()’ can also correctly un-stringize stringized
annotations.  ‘inspect.get_annotations()’ is now considered best
practice for accessing the annotations dict defined on any Python
object; for more information on best practices for working with
annotations, please see *note Annotations Best Practices: 7dd.
Relatedly, *note inspect.signature(): 73b, *note
inspect.Signature.from_callable(): 73d, and
‘inspect.Signature.from_function()’ now call ‘inspect.get_annotations()’
to retrieve annotations.  This means ‘inspect.signature()’ and
‘inspect.Signature.from_callable()’ can also now un-stringize stringized
annotations.  (Contributed by Larry Hastings in bpo-43817(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42133

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43817


File: python.info,  Node: itertools<3>,  Next: linecache,  Prev: inspect<3>,  Up: Improved Modules<4>

1.4.6.28 itertools
..................

Add *note itertools.pairwise(): 81b.  (Contributed by Raymond Hettinger
in bpo-38200(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38200


File: python.info,  Node: linecache,  Next: os<4>,  Prev: itertools<3>,  Up: Improved Modules<4>

1.4.6.29 linecache
..................

When a module does not define ‘__loader__’, fall back to
‘__spec__.loader’.  (Contributed by Brett Cannon in bpo-42133(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42133


File: python.info,  Node: os<4>,  Next: os path<4>,  Prev: linecache,  Up: Improved Modules<4>

1.4.6.30 os
...........

Add *note os.cpu_count(): 1c5. support for VxWorks RTOS. (Contributed by
Peixing Xin in bpo-41440(1).)

Add a new function *note os.eventfd(): 81e. and related helpers to wrap
the ‘eventfd2’ syscall on Linux.  (Contributed by Christian Heimes in
bpo-41001(2).)

Add *note os.splice(): 81f. that allows to move data between two file
descriptors without copying between kernel address space and user
address space, where one of the file descriptors must refer to a pipe.
(Contributed by Pablo Galindo in bpo-41625(3).)

Add *note O_EVTONLY: 820, *note O_FSYNC: 821, *note O_SYMLINK: 822. and
*note O_NOFOLLOW_ANY: 823. for macOS. (Contributed by Donghee Na in
bpo-43106(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41440

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41001

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41625

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43106


File: python.info,  Node: os path<4>,  Next: pathlib<5>,  Prev: os<4>,  Up: Improved Modules<4>

1.4.6.31 os.path
................

*note os.path.realpath(): 225. now accepts a 'strict' keyword-only
argument.  When set to ‘True’, *note OSError: 41a. is raised if a path
doesn’t exist or a symlink loop is encountered.  (Contributed by Barney
Gale in bpo-43757(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43757


File: python.info,  Node: pathlib<5>,  Next: platform<2>,  Prev: os path<4>,  Up: Improved Modules<4>

1.4.6.32 pathlib
................

Add slice support to *note PurePath.parents: 826.  (Contributed by
Joshua Cannon in bpo-35498(1).)

Add negative indexing support to *note PurePath.parents: 826.
(Contributed by Yaroslav Pankovych in bpo-21041(2).)

Add *note Path.hardlink_to: 827. method that supersedes ‘link_to()’.
The new method has the same argument order as *note symlink_to(): 828.
(Contributed by Barney Gale in bpo-39950(3).)

*note pathlib.Path.stat(): 829. and *note chmod(): 82a. now accept a
'follow_symlinks' keyword-only argument for consistency with
corresponding functions in the *note os: a1. module.  (Contributed by
Barney Gale in bpo-39906(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35498

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21041

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39950

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39906


File: python.info,  Node: platform<2>,  Next: pprint,  Prev: pathlib<5>,  Up: Improved Modules<4>

1.4.6.33 platform
.................

Add *note platform.freedesktop_os_release(): 82c. to retrieve operation
system identification from freedesktop.org os-release(1) standard file.
(Contributed by Christian Heimes in bpo-28468(2).)

   ---------- Footnotes ----------

   (1) https://www.freedesktop.org/software/systemd/man/os-release.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28468


File: python.info,  Node: pprint,  Next: py_compile,  Prev: platform<2>,  Up: Improved Modules<4>

1.4.6.34 pprint
...............

*note pprint.pprint(): 82e. now accepts a new ‘underscore_numbers’
keyword argument.  (Contributed by sblondon in bpo-42914(1).)

*note pprint: ae. can now pretty-print *note dataclasses.dataclass: 1cb.
instances.  (Contributed by Lewis Gaul in bpo-43080(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42914

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43080


File: python.info,  Node: py_compile,  Next: pyclbr,  Prev: pprint,  Up: Improved Modules<4>

1.4.6.35 py_compile
...................

Add ‘--quiet’ option to command-line interface of *note py_compile: b3.
(Contributed by Gregory Schevchenko in bpo-38731(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38731


File: python.info,  Node: pyclbr,  Next: shelve,  Prev: py_compile,  Up: Improved Modules<4>

1.4.6.36 pyclbr
...............

Add an ‘end_lineno’ attribute to the ‘Function’ and ‘Class’ objects in
the tree returned by *note pyclbr.readmodule(): 831. and *note
pyclbr.readmodule_ex(): 832.  It matches the existing (start) ‘lineno’.
(Contributed by Aviral Srivastava in bpo-38307(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38307


File: python.info,  Node: shelve,  Next: statistics<3>,  Prev: pyclbr,  Up: Improved Modules<4>

1.4.6.37 shelve
...............

The *note shelve: c3. module now uses *note pickle.DEFAULT_PROTOCOL:
834. by default instead of *note pickle: a6. protocol ‘3’ when creating
shelves.  (Contributed by Zackery Spytz in bpo-34204(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34204


File: python.info,  Node: statistics<3>,  Next: site<2>,  Prev: shelve,  Up: Improved Modules<4>

1.4.6.38 statistics
...................

Add *note covariance(): 836, Pearson’s *note correlation(): 4bf, and
simple *note linear_regression(): 837. functions.  (Contributed by
Tymoteusz Wołodźko in bpo-38490(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38490


File: python.info,  Node: site<2>,  Next: socket<2>,  Prev: statistics<3>,  Up: Improved Modules<4>

1.4.6.39 site
.............

When a module does not define ‘__loader__’, fall back to
‘__spec__.loader’.  (Contributed by Brett Cannon in bpo-42133(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42133


File: python.info,  Node: socket<2>,  Next: ssl<3>,  Prev: site<2>,  Up: Improved Modules<4>

1.4.6.40 socket
...............

The exception *note socket.timeout: 83a. is now an alias of *note
TimeoutError: 83b.  (Contributed by Christian Heimes in bpo-42413(1).)

Add option to create MPTCP sockets with ‘IPPROTO_MPTCP’ (Contributed by
Rui Cunha in bpo-43571(2).)

Add ‘IP_RECVTOS’ option to receive the type of service (ToS) or DSCP/ECN
fields (Contributed by Georg Sauthoff in bpo-44077(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42413

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43571

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44077


File: python.info,  Node: ssl<3>,  Next: sqlite3<5>,  Prev: socket<2>,  Up: Improved Modules<4>

1.4.6.41 ssl
............

The ssl module requires OpenSSL 1.1.1 or newer.  (Contributed by
Christian Heimes in PEP 644(1) and bpo-43669(2).)

The ssl module has preliminary support for OpenSSL 3.0.0 and new option
*note OP_IGNORE_UNEXPECTED_EOF: 83d.  (Contributed by Christian Heimes
in bpo-38820(3), bpo-43794(4), bpo-43788(5), bpo-43791(6), bpo-43799(7),
bpo-43920(8), bpo-43789(9), and bpo-43811(10).)

Deprecated function and use of deprecated constants now result in a
*note DeprecationWarning: 1a5.  *note ssl.SSLContext.options: 83e. has
*note OP_NO_SSLv2: 83f. and *note OP_NO_SSLv3: 840. set by default and
therefore cannot warn about setting the flag again.  The *note
deprecation section: 841. has a list of deprecated features.
(Contributed by Christian Heimes in bpo-43880(11).)

The ssl module now has more secure default settings.  Ciphers without
forward secrecy or SHA-1 MAC are disabled by default.  Security level 2
prohibits weak RSA, DH, and ECC keys with less than 112 bits of
security.  *note SSLContext: 294. defaults to minimum protocol version
TLS 1.2.  Settings are based on Hynek Schlawack’s research.
(Contributed by Christian Heimes in bpo-43998(12).)

The deprecated protocols SSL 3.0, TLS 1.0, and TLS 1.1 are no longer
officially supported.  Python does not block them actively.  However
OpenSSL build options, distro configurations, vendor patches, and cipher
suites may prevent a successful handshake.

Add a 'timeout' parameter to the *note ssl.get_server_certificate():
842. function.  (Contributed by Zackery Spytz in bpo-31870(13).)

The ssl module uses heap-types and multi-phase initialization.
(Contributed by Christian Heimes in bpo-42333(14).)

A new verify flag *note VERIFY_X509_PARTIAL_CHAIN: 156. has been added.
(Contributed by l0x in bpo-40849(15).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0644/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43669

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38820

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43794

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43788

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43791

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43799

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43920

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43789

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43811

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43880

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43998

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31870

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42333

   (15) https://bugs.python.org/issue?@action=redirect&bpo=40849


File: python.info,  Node: sqlite3<5>,  Next: sys<5>,  Prev: ssl<3>,  Up: Improved Modules<4>

1.4.6.42 sqlite3
................

Add audit events for *note connect(): 2a8, *note
enable_load_extension(): 844, and *note load_extension(): 4bb.
(Contributed by Erlend E. Aasland in bpo-43762(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43762


File: python.info,  Node: sys<5>,  Next: _thread,  Prev: sqlite3<5>,  Up: Improved Modules<4>

1.4.6.43 sys
............

Add *note sys.orig_argv: 846. attribute: the list of the original
command line arguments passed to the Python executable.  (Contributed by
Victor Stinner in bpo-23427(1).)

Add *note sys.stdlib_module_names: 847, containing the list of the
standard library module names.  (Contributed by Victor Stinner in
bpo-42955(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23427

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42955


File: python.info,  Node: _thread,  Next: threading<3>,  Prev: sys<5>,  Up: Improved Modules<4>

1.4.6.44 _thread
................

*note _thread.interrupt_main(): 849. now takes an optional signal number
to simulate (the default is still *note signal.SIGINT: 84a.).
(Contributed by Antoine Pitrou in bpo-43356(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43356


File: python.info,  Node: threading<3>,  Next: traceback<3>,  Prev: _thread,  Up: Improved Modules<4>

1.4.6.45 threading
..................

Add *note threading.gettrace(): 84c. and *note threading.getprofile():
84d. to retrieve the functions set by *note threading.settrace(): 84e.
and *note threading.setprofile(): 84f. respectively.  (Contributed by
Mario Corchero in bpo-42251(1).)

Add *note threading.__excepthook__: 850. to allow retrieving the
original value of *note threading.excepthook(): 851. in case it is set
to a broken or a different value.  (Contributed by Mario Corchero in
bpo-42308(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42251

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42308


File: python.info,  Node: traceback<3>,  Next: types<3>,  Prev: threading<3>,  Up: Improved Modules<4>

1.4.6.46 traceback
..................

The *note format_exception(): 853, *note format_exception_only(): 854,
and *note print_exception(): 855. functions can now take an exception
object as a positional-only argument.  (Contributed by Zackery Spytz and
Matthias Bussonnier in bpo-26389(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26389


File: python.info,  Node: types<3>,  Next: typing<5>,  Prev: traceback<3>,  Up: Improved Modules<4>

1.4.6.47 types
..............

Reintroduce the *note types.EllipsisType: 857, *note types.NoneType:
858. and *note types.NotImplementedType: 859. classes, providing a new
set of types readily interpretable by type checkers.  (Contributed by
Bas van Beek in bpo-41810(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41810


File: python.info,  Node: typing<5>,  Next: unittest<5>,  Prev: types<3>,  Up: Improved Modules<4>

1.4.6.48 typing
...............

For major changes, see *note New Features Related to Type Hints: 7c2.

The behavior of *note typing.Literal: 85b. was changed to conform with
PEP 586(1) and to match the behavior of static type checkers specified
in the PEP.

  1. ‘Literal’ now de-duplicates parameters.

  2. Equality comparisons between ‘Literal’ objects are now order
     independent.

  3. ‘Literal’ comparisons now respect types.  For example, ‘Literal[0]
     == Literal[False]’ previously evaluated to ‘True’.  It is now
     ‘False’.  To support this change, the internally used type cache
     now supports differentiating types.

  4. ‘Literal’ objects will now raise a *note TypeError: 2c3. exception
     during equality comparisons if any of their parameters are not
     *note hashable: 613.  Note that declaring ‘Literal’ with unhashable
     parameters will not throw an error:

          >>> from typing import Literal
          >>> Literal[{0}]
          >>> Literal[{0}] == Literal[{False}]
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          TypeError: unhashable type: 'set'

(Contributed by Yurii Karabas in bpo-42345(2).)

Add new function *note typing.is_typeddict(): 85c. to introspect if an
annotation is a *note typing.TypedDict: 162.  (Contributed by Patrick
Reader in bpo-41792(3).)

Subclasses of ‘typing.Protocol’ which only have data variables declared
will now raise a ‘TypeError’ when checked with ‘isinstance’ unless they
are decorated with *note runtime_checkable(): 446.  Previously, these
checks passed silently.  Users should decorate their subclasses with the
‘runtime_checkable()’ decorator if they want runtime protocols.
(Contributed by Yurii Karabas in bpo-38908(4).)

Importing from the ‘typing.io’ and ‘typing.re’ submodules will now emit
*note DeprecationWarning: 1a5.  These submodules have been deprecated
since Python 3.8 and will be removed in a future version of Python.
Anything belonging to those submodules should be imported directly from
*note typing: 104. instead.  (Contributed by Sebastian Rittau in
bpo-38291(5).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0586/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42345

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41792

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38908

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38291


File: python.info,  Node: unittest<5>,  Next: urllib parse,  Prev: typing<5>,  Up: Improved Modules<4>

1.4.6.49 unittest
.................

Add new method *note assertNoLogs(): 85e. to complement the existing
*note assertLogs(): 85f.  (Contributed by Kit Yan Choi in bpo-39385(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39385


File: python.info,  Node: urllib parse,  Next: xml<2>,  Prev: unittest<5>,  Up: Improved Modules<4>

1.4.6.50 urllib.parse
.....................

Python versions earlier than Python 3.10 allowed using both ‘;’ and ‘&’
as query parameter separators in *note urllib.parse.parse_qs(): 27a. and
*note urllib.parse.parse_qsl(): 279.  Due to security concerns, and to
conform with newer W3C recommendations, this has been changed to allow
only a single separator key, with ‘&’ as the default.  This change also
affects ‘cgi.parse()’ and ‘cgi.parse_multipart()’ as they use the
affected functions internally.  For more details, please see their
respective documentation.  (Contributed by Adam Goldschmidt, Senthil
Kumaran and Ken Jin in bpo-42967(1).)

The presence of newline or tab characters in parts of a URL allows for
some forms of attacks.  Following the WHATWG specification that updates
RFC 3986(2), ASCII newline ‘\n’, ‘\r’ and tab ‘\t’ characters are
stripped from the URL by the parser in *note urllib.parse: 10a.
preventing such attacks.  The removal characters are controlled by a new
module level variable ‘urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE’.  (See
gh-88048(3))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967

   (2) https://datatracker.ietf.org/doc/html/rfc3986.html

   (3) https://github.com/python/cpython/issues/88048


File: python.info,  Node: xml<2>,  Next: zipimport<3>,  Prev: urllib parse,  Up: Improved Modules<4>

1.4.6.51 xml
............

Add a *note LexicalHandler: 862. class to the *note xml.sax.handler:
12a. module.  (Contributed by Jonathan Gossage and Zackery Spytz in
bpo-35018(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35018


File: python.info,  Node: zipimport<3>,  Prev: xml<2>,  Up: Improved Modules<4>

1.4.6.52 zipimport
..................

Add methods related to PEP 451(1): *note find_spec(): 864, *note
zipimport.zipimporter.create_module(): 865, and *note
zipimport.zipimporter.exec_module(): 312.  (Contributed by Brett Cannon
in bpo-42131(2).)

Add *note invalidate_caches(): 866. method.  (Contributed by Desmond
Cheong in bpo-14678(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0451/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42131

   (3) https://bugs.python.org/issue?@action=redirect&bpo=14678


File: python.info,  Node: Optimizations<4>,  Next: Deprecated<5>,  Prev: Improved Modules<4>,  Up: What’s New In Python 3 10

1.4.7 Optimizations
-------------------

   * Constructors *note str(): 44f, *note bytes(): 1c2. and *note
     bytearray(): 2ea. are now faster (around 30–40% for small objects).
     (Contributed by Serhiy Storchaka in bpo-41334(1).)

   * The *note runpy: be. module now imports fewer modules.  The
     ‘python3 -m module-name’ command startup time is 1.4x faster in
     average.  On Linux, ‘python3 -I -m module-name’ imports 69 modules
     on Python 3.9, whereas it only imports 51 modules (-18) on Python
     3.10.  (Contributed by Victor Stinner in bpo-41006(2) and
     bpo-41718(3).)

   * The ‘LOAD_ATTR’ instruction now uses new “per opcode cache”
     mechanism.  It is about 36% faster now for regular attributes and
     44% faster for slots.  (Contributed by Pablo Galindo and Yury
     Selivanov in bpo-42093(4) and Guido van Rossum in bpo-42927(5),
     based on ideas implemented originally in PyPy and MicroPython.)

   * When building Python with *note -enable-optimizations: 868. now
     ‘-fno-semantic-interposition’ is added to both the compile and link
     line.  This speeds builds of the Python interpreter created with
     *note -enable-shared: 869. with ‘gcc’ by up to 30%.  See this
     article(6) for more details.  (Contributed by Victor Stinner and
     Pablo Galindo in bpo-38980(7).)

   * Use a new output buffer management code for *note bz2: 13. / *note
     lzma: 8a. / *note zlib: 133. modules, and add ‘.readall()’ function
     to ‘_compression.DecompressReader’ class.  bz2 decompression is now
     1.09x ~ 1.17x faster, lzma decompression 1.20x ~ 1.32x faster,
     ‘GzipFile.read(-1)’ 1.11x ~ 1.18x faster.  (Contributed by Ma Lin,
     reviewed by Gregory P. Smith, in bpo-41486(8))

   * When using stringized annotations, annotations dicts for functions
     are no longer created when the function is created.  Instead, they
     are stored as a tuple of strings, and the function object lazily
     converts this into the annotations dict on demand.  This
     optimization cuts the CPU time needed to define an annotated
     function by half.  (Contributed by Yurii Karabas and Inada Naoki in
     bpo-42202(9).)

   * Substring search functions such as ‘str1 in str2’ and
     ‘str2.find(str1)’ now sometimes use Crochemore & Perrin’s “Two-Way”
     string searching algorithm to avoid quadratic behavior on long
     strings.  (Contributed by Dennis Sweeney in bpo-41972(10))

   * Add micro-optimizations to ‘_PyType_Lookup()’ to improve type
     attribute cache lookup performance in the common case of cache
     hits.  This makes the interpreter 1.04 times faster on average.
     (Contributed by Dino Viehland in bpo-43452(11).)

   * The following built-in functions now support the faster PEP 590(12)
     vectorcall calling convention: *note map(): 86a, *note filter():
     86b, *note reversed(): 86c, *note bool(): 46b. and *note float():
     2f7.  (Contributed by Donghee Na and Jeroen Demeyer in
     bpo-43575(13), bpo-43287(14), bpo-41922(15), bpo-41873(16) and
     bpo-41870(17).)

   * *note BZ2File: 86d. performance is improved by removing internal
     ‘RLock’.  This makes ‘BZ2File’ thread unsafe in the face of
     multiple simultaneous readers or writers, just like its equivalent
     classes in *note gzip: 67. and *note lzma: 8a. have always been.
     (Contributed by Inada Naoki in bpo-43785(18).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41334

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41006

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41718

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42093

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42927

   (6) 
https://developers.redhat.com/blog/2020/06/25/red-hat-enterprise-linux-8-2-brings-faster-python-3-8-run-speeds/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38980

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41486

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42202

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41972

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43452

   (12) https://peps.python.org/pep-0590/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43575

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43287

   (15) https://bugs.python.org/issue?@action=redirect&bpo=41922

   (16) https://bugs.python.org/issue?@action=redirect&bpo=41873

   (17) https://bugs.python.org/issue?@action=redirect&bpo=41870

   (18) https://bugs.python.org/issue?@action=redirect&bpo=43785


File: python.info,  Node: Deprecated<5>,  Next: Removed<5>,  Prev: Optimizations<4>,  Up: What’s New In Python 3 10

1.4.8 Deprecated
----------------

   * Currently Python accepts numeric literals immediately followed by
     keywords, for example ‘0in x’, ‘1or x’, ‘0if 1else 2’.  It allows
     confusing and ambiguous expressions like ‘[0x1for x in y]’ (which
     can be interpreted as ‘[0x1 for x in y]’ or ‘[0x1f or x in y]’).
     Starting in this release, a deprecation warning is raised if the
     numeric literal is immediately followed by one of keywords *note
     and: 2f1, *note else: 18c, *note for: 2f2, *note if: 2f3, *note in:
     2f4, *note is: 2f5. and *note or: 2f6.  In future releases it will
     be changed to syntax warning, and finally to syntax error.
     (Contributed by Serhiy Storchaka in bpo-43833(1).)

   * Starting in this release, there will be a concerted effort to begin
     cleaning up old import semantics that were kept for Python 2.7
     compatibility.  Specifically, ‘find_loader()’/‘find_module()’
     (superseded by *note find_spec(): 86f.), *note load_module(): 870.
     (superseded by *note exec_module(): 871.), ‘module_repr()’ (which
     the import system takes care of for you), the ‘__package__’
     attribute (superseded by ‘__spec__.parent’), the ‘__loader__’
     attribute (superseded by ‘__spec__.loader’), and the ‘__cached__’
     attribute (superseded by ‘__spec__.cached’) will slowly be removed
     (as well as other classes and methods in *note importlib: 77.).
     *note ImportWarning: 4fd. and/or *note DeprecationWarning: 1a5.
     will be raised as appropriate to help identify code which needs
     updating during this transition.

   * The entire ‘distutils’ namespace is deprecated, to be removed in
     Python 3.12.  Refer to the *note module changes: 72d. section for
     more information.

   * Non-integer arguments to *note random.randrange(): 872. are
     deprecated.  The *note ValueError: 202. is deprecated in favor of a
     *note TypeError: 2c3.  (Contributed by Serhiy Storchaka and Raymond
     Hettinger in bpo-37319(2).)

   * The various ‘load_module()’ methods of *note importlib: 77. have
     been documented as deprecated since Python 3.6, but will now also
     trigger a *note DeprecationWarning: 1a5.  Use *note exec_module():
     871. instead.  (Contributed by Brett Cannon in bpo-26131(3).)

   * ‘zimport.zipimporter.load_module()’ has been deprecated in
     preference for *note exec_module(): 312.  (Contributed by Brett
     Cannon in bpo-26131(4).)

   * The use of *note load_module(): 870. by the import system now
     triggers an *note ImportWarning: 4fd. as *note exec_module(): 871.
     is preferred.  (Contributed by Brett Cannon in bpo-26131(5).)

   * The use of ‘importlib.abc.MetaPathFinder.find_module()’ and
     ‘importlib.abc.PathEntryFinder.find_module()’ by the import system
     now trigger an *note ImportWarning: 4fd. as *note
     importlib.abc.MetaPathFinder.find_spec(): 86f. and *note
     importlib.abc.PathEntryFinder.find_spec(): 873. are preferred,
     respectively.  You can use *note importlib.util.spec_from_loader():
     874. to help in porting.  (Contributed by Brett Cannon in
     bpo-42134(6).)

   * The use of ‘importlib.abc.PathEntryFinder.find_loader()’ by the
     import system now triggers an *note ImportWarning: 4fd. as *note
     importlib.abc.PathEntryFinder.find_spec(): 873. is preferred.  You
     can use *note importlib.util.spec_from_loader(): 874. to help in
     porting.  (Contributed by Brett Cannon in bpo-43672(7).)

   * The various implementations of
     ‘importlib.abc.MetaPathFinder.find_module()’ (
     ‘importlib.machinery.BuiltinImporter.find_module()’,
     ‘importlib.machinery.FrozenImporter.find_module()’,
     ‘importlib.machinery.WindowsRegistryFinder.find_module()’,
     ‘importlib.machinery.PathFinder.find_module()’,
     ‘importlib.abc.MetaPathFinder.find_module()’ ),
     ‘importlib.abc.PathEntryFinder.find_module()’ (
     ‘importlib.machinery.FileFinder.find_module()’ ), and
     ‘importlib.abc.PathEntryFinder.find_loader()’ (
     ‘importlib.machinery.FileFinder.find_loader()’ ) now raise *note
     DeprecationWarning: 1a5. and are slated for removal in Python 3.12
     (previously they were documented as deprecated in Python 3.4).
     (Contributed by Brett Cannon in bpo-42135(8).)

   * ‘importlib.abc.Finder’ is deprecated (including its sole method,
     ‘find_module()’).  Both *note importlib.abc.MetaPathFinder: 875.
     and *note importlib.abc.PathEntryFinder: 876. no longer inherit
     from the class.  Users should inherit from one of these two classes
     as appropriate instead.  (Contributed by Brett Cannon in
     bpo-42135(9).)

   * The deprecations of ‘imp’, ‘importlib.find_loader()’,
     ‘importlib.util.set_package_wrapper()’,
     ‘importlib.util.set_loader_wrapper()’,
     ‘importlib.util.module_for_loader()’, ‘pkgutil.ImpImporter’, and
     ‘pkgutil.ImpLoader’ have all been updated to list Python 3.12 as
     the slated version of removal (they began raising *note
     DeprecationWarning: 1a5. in previous versions of Python).
     (Contributed by Brett Cannon in bpo-43720(10).)

   * The import system now uses the ‘__spec__’ attribute on modules
     before falling back on ‘module_repr()’ for a module’s ‘__repr__()’
     method.  Removal of the use of ‘module_repr()’ is scheduled for
     Python 3.12.  (Contributed by Brett Cannon in bpo-42137(11).)

   * ‘importlib.abc.Loader.module_repr()’,
     ‘importlib.machinery.FrozenLoader.module_repr()’, and
     ‘importlib.machinery.BuiltinLoader.module_repr()’ are deprecated
     and slated for removal in Python 3.12.  (Contributed by Brett
     Cannon in bpo-42136(12).)

   * ‘sqlite3.OptimizedUnicode’ has been undocumented and obsolete since
     Python 3.3, when it was made an alias to *note str: 44f.  It is now
     deprecated, scheduled for removal in Python 3.12.  (Contributed by
     Erlend E. Aasland in bpo-42264(13).)

   * The undocumented built-in function ‘sqlite3.enable_shared_cache’ is
     now deprecated, scheduled for removal in Python 3.12.  Its use is
     strongly discouraged by the SQLite3 documentation.  See the SQLite3
     docs(14) for more details.  If a shared cache must be used, open
     the database in URI mode using the ‘cache=shared’ query parameter.
     (Contributed by Erlend E. Aasland in bpo-24464(15).)

   * The following ‘threading’ methods are now deprecated:

        * ‘threading.currentThread’ => *note threading.current_thread():
          309.

        * ‘threading.activeCount’ => *note threading.active_count():
          30a.

        * ‘threading.Condition.notifyAll’ => *note
          threading.Condition.notify_all(): 303.

        * ‘threading.Event.isSet’ => *note threading.Event.is_set():
          304.

        * ‘threading.Thread.setName’ => *note threading.Thread.name:
          308.

        * ‘threading.thread.getName’ => *note threading.Thread.name:
          308.

        * ‘threading.Thread.isDaemon’ => *note threading.Thread.daemon:
          306.

        * ‘threading.Thread.setDaemon’ => *note threading.Thread.daemon:
          306.

     (Contributed by Jelle Zijlstra in gh-87889(16).)

   * ‘pathlib.Path.link_to()’ is deprecated and slated for removal in
     Python 3.12.  Use *note pathlib.Path.hardlink_to(): 827. instead.
     (Contributed by Barney Gale in bpo-39950(17).)

   * ‘cgi.log()’ is deprecated and slated for removal in Python 3.12.
     (Contributed by Inada Naoki in bpo-41139(18).)

   * The following *note ssl: d0. features have been deprecated since
     Python 3.6, Python 3.7, or OpenSSL 1.1.0 and will be removed in
     3.11:

        * ‘OP_NO_SSLv2’, ‘OP_NO_SSLv3’, ‘OP_NO_TLSv1’, ‘OP_NO_TLSv1_1’,
          ‘OP_NO_TLSv1_2’, and ‘OP_NO_TLSv1_3’ are replaced by *note
          minimum_version: 877. and *note maximum_version: 878.

        * ‘PROTOCOL_SSLv2’, ‘PROTOCOL_SSLv3’, ‘PROTOCOL_SSLv23’,
          ‘PROTOCOL_TLSv1’, ‘PROTOCOL_TLSv1_1’, ‘PROTOCOL_TLSv1_2’, and
          ‘PROTOCOL_TLS’ are deprecated in favor of *note
          PROTOCOL_TLS_CLIENT: 879. and *note PROTOCOL_TLS_SERVER: 87a.

        * ‘wrap_socket()’ is replaced by *note
          ssl.SSLContext.wrap_socket(): 528.

        * ‘match_hostname()’

        * ‘RAND_pseudo_bytes()’, ‘RAND_egd()’

        * NPN features like *note ssl.SSLSocket.selected_npn_protocol():
          87b. and *note ssl.SSLContext.set_npn_protocols(): 302. are
          replaced by ALPN.

   * The threading debug (‘PYTHONTHREADDEBUG’ environment variable) is
     deprecated in Python 3.10 and will be removed in Python 3.12.  This
     feature requires a *note debug build of Python: 1f9.  (Contributed
     by Victor Stinner in bpo-44584(19).)

   * Importing from the ‘typing.io’ and ‘typing.re’ submodules will now
     emit *note DeprecationWarning: 1a5.  These submodules will be
     removed in a future version of Python.  Anything belonging to these
     submodules should be imported directly from *note typing: 104.
     instead.  (Contributed by Sebastian Rittau in bpo-38291(20).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43833

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37319

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26131

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26131

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26131

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42134

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43672

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42135

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42135

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43720

   (11) https://bugs.python.org/issue?@action=redirect&bpo=42137

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42136

   (13) https://bugs.python.org/issue?@action=redirect&bpo=42264

   (14) https://sqlite.org/c3ref/enable_shared_cache.html

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24464

   (16) https://github.com/python/cpython/issues/87889

   (17) https://bugs.python.org/issue?@action=redirect&bpo=39950

   (18) https://bugs.python.org/issue?@action=redirect&bpo=41139

   (19) https://bugs.python.org/issue?@action=redirect&bpo=44584

   (20) https://bugs.python.org/issue?@action=redirect&bpo=38291


File: python.info,  Node: Removed<5>,  Next: Porting to Python 3 10,  Prev: Deprecated<5>,  Up: What’s New In Python 3 10

1.4.9 Removed
-------------

   * Removed special methods ‘__int__’, ‘__float__’, ‘__floordiv__’,
     ‘__mod__’, ‘__divmod__’, ‘__rfloordiv__’, ‘__rmod__’ and
     ‘__rdivmod__’ of the *note complex: 2f8. class.  They always raised
     a *note TypeError: 2c3.  (Contributed by Serhiy Storchaka in
     bpo-41974(1).)

   * The ‘ParserBase.error()’ method from the private and undocumented
     ‘_markupbase’ module has been removed.  *note
     html.parser.HTMLParser: 87e. is the only subclass of ‘ParserBase’
     and its ‘error()’ implementation was already removed in Python 3.5.
     (Contributed by Berker Peksag in bpo-31844(2).)

   * Removed the ‘unicodedata.ucnhash_CAPI’ attribute which was an
     internal PyCapsule object.  The related private
     ‘_PyUnicode_Name_CAPI’ structure was moved to the internal C API.
     (Contributed by Victor Stinner in bpo-42157(3).)

   * Removed the ‘parser’ module, which was deprecated in 3.9 due to the
     switch to the new PEG parser, as well as all the C source and
     header files that were only being used by the old parser, including
     ‘node.h’, ‘parser.h’, ‘graminit.h’ and ‘grammar.h’.

   * Removed the Public C API functions
     ‘PyParser_SimpleParseStringFlags’,
     ‘PyParser_SimpleParseStringFlagsFilename’,
     ‘PyParser_SimpleParseFileFlags’ and ‘PyNode_Compile’ that were
     deprecated in 3.9 due to the switch to the new PEG parser.

   * Removed the ‘formatter’ module, which was deprecated in Python 3.4.
     It is somewhat obsolete, little used, and not tested.  It was
     originally scheduled to be removed in Python 3.6, but such removals
     were delayed until after Python 2.7 EOL. Existing users should copy
     whatever classes they use into their code.  (Contributed by Donghee
     Na and Terry J. Reedy in bpo-42299(4).)

   * Removed the ‘PyModule_GetWarningsModule()’ function that was
     useless now due to the ‘_warnings’ module was converted to a
     builtin module in 2.6.  (Contributed by Hai Shi in bpo-42599(5).)

   * Remove deprecated aliases to *note Collections Abstract Base
     Classes: 87f. from the *note collections: 1d. module.  (Contributed
     by Victor Stinner in bpo-37324(6).)

   * The ‘loop’ parameter has been removed from most of *note asyncio:
     a.‘s *note high-level API: 880. following deprecation in Python
     3.8.  The motivation behind this change is multifold:

       1. This simplifies the high-level API.

       2. The functions in the high-level API have been implicitly
          getting the current thread’s running event loop since Python
          3.7.  There isn’t a need to pass the event loop to the API in
          most normal use cases.

       3. Event loop passing is error-prone especially when dealing with
          loops running in different threads.

     Note that the low-level API will still accept ‘loop’.  See *note
     Changes in the Python API: 881. for examples of how to replace
     existing code.

     (Contributed by Yurii Karabas, Andrew Svetlov, Yury Selivanov and
     Kyle Stanley in bpo-42392(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41974

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31844

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42157

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42299

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42599

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37324

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42392


File: python.info,  Node: Porting to Python 3 10,  Next: CPython bytecode changes<3>,  Prev: Removed<5>,  Up: What’s New In Python 3 10

1.4.10 Porting to Python 3.10
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in the Python syntax::
* Changes in the Python API: Changes in the Python API<3>.
* Changes in the C API: Changes in the C API<2>.


File: python.info,  Node: Changes in the Python syntax,  Next: Changes in the Python API<3>,  Up: Porting to Python 3 10

1.4.10.1 Changes in the Python syntax
.....................................

   * Deprecation warning is now emitted when compiling previously valid
     syntax if the numeric literal is immediately followed by a keyword
     (like in ‘0in x’).  In future releases it will be changed to syntax
     warning, and finally to a syntax error.  To get rid of the warning
     and make the code compatible with future releases just add a space
     between the numeric literal and the following keyword.
     (Contributed by Serhiy Storchaka in bpo-43833(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43833


File: python.info,  Node: Changes in the Python API<3>,  Next: Changes in the C API<2>,  Prev: Changes in the Python syntax,  Up: Porting to Python 3 10

1.4.10.2 Changes in the Python API
..................................

   * The 'etype' parameters of the *note format_exception(): 853, *note
     format_exception_only(): 854, and *note print_exception(): 855.
     functions in the *note traceback: fe. module have been renamed to
     'exc'.  (Contributed by Zackery Spytz and Matthias Bussonnier in
     bpo-26389(1).)

   * *note atexit: c.: At Python exit, if a callback registered with
     *note atexit.register(): 885. fails, its exception is now logged.
     Previously, only some exceptions were logged, and the last
     exception was always silently ignored.  (Contributed by Victor
     Stinner in bpo-42639(2).)

   * *note collections.abc.Callable: 7ef. generic now flattens type
     parameters, similar to what *note typing.Callable: 7c9. currently
     does.  This means that ‘collections.abc.Callable[[int, str], str]’
     will have ‘__args__’ of ‘(int, str, str)’; previously this was
     ‘([int, str], str)’.  Code which accesses the arguments via *note
     typing.get_args(): 2ed. or ‘__args__’ need to account for this
     change.  Furthermore, *note TypeError: 2c3. may be raised for
     invalid forms of parameterizing ‘collections.abc.Callable’ which
     may have passed silently in Python 3.9.  (Contributed by Ken Jin in
     bpo-42195(3).)

   * *note socket.htons(): 886. and *note socket.ntohs(): 887. now raise
     *note OverflowError: 888. instead of *note DeprecationWarning: 1a5.
     if the given parameter will not fit in a 16-bit unsigned integer.
     (Contributed by Erlend E. Aasland in bpo-42393(4).)

   * The ‘loop’ parameter has been removed from most of *note asyncio:
     a.‘s *note high-level API: 880. following deprecation in Python
     3.8.

     A coroutine that currently looks like this:

          async def foo(loop):
              await asyncio.sleep(1, loop=loop)

     Should be replaced with this:

          async def foo():
              await asyncio.sleep(1)

     If ‘foo()’ was specifically designed 'not' to run in the current
     thread’s running event loop (e.g.  running in another thread’s
     event loop), consider using *note
     asyncio.run_coroutine_threadsafe(): 889. instead.

     (Contributed by Yurii Karabas, Andrew Svetlov, Yury Selivanov and
     Kyle Stanley in bpo-42392(5).)

   * The *note types.FunctionType: 88a. constructor now inherits the
     current builtins if the 'globals' dictionary has no
     ‘"__builtins__"’ key, rather than using ‘{"None": None}’ as
     builtins: same behavior as *note eval(): 180. and *note exec():
     17f. functions.  Defining a function with ‘def function(...): ...’
     in Python is not affected, globals cannot be overridden with this
     syntax: it also inherits the current builtins.  (Contributed by
     Victor Stinner in bpo-42990(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26389

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42639

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42195

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42393

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42392

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42990


File: python.info,  Node: Changes in the C API<2>,  Prev: Changes in the Python API<3>,  Up: Porting to Python 3 10

1.4.10.3 Changes in the C API
.............................

   * The C API functions ‘PyParser_SimpleParseStringFlags’,
     ‘PyParser_SimpleParseStringFlagsFilename’,
     ‘PyParser_SimpleParseFileFlags’, ‘PyNode_Compile’ and the type used
     by these functions, ‘struct _node’, were removed due to the switch
     to the new PEG parser.

     Source should be now be compiled directly to a code object using,
     for example, *note Py_CompileString(): 88c.  The resulting code
     object can then be evaluated using, for example, *note
     PyEval_EvalCode(): 88d.

     Specifically:

        * A call to ‘PyParser_SimpleParseStringFlags’ followed by
          ‘PyNode_Compile’ can be replaced by calling *note
          Py_CompileString(): 88c.

        * There is no direct replacement for
          ‘PyParser_SimpleParseFileFlags’.  To compile code from a ‘FILE
          *’ argument, you will need to read the file in C and pass the
          resulting buffer to *note Py_CompileString(): 88c.

        * To compile a file given a ‘char *’ filename, explicitly open
          the file, read it and compile the result.  One way to do this
          is using the *note io: 7f. module with *note
          PyImport_ImportModule(): 3c1, *note PyObject_CallMethod():
          3a2, *note PyBytes_AsString(): 88e. and *note
          Py_CompileString(): 88c, as sketched below.  (Declarations and
          error handling are omitted.)

               io_module = Import_ImportModule("io");
               fileobject = PyObject_CallMethod(io_module, "open", "ss", filename, "rb");
               source_bytes_object = PyObject_CallMethod(fileobject, "read", "");
               result = PyObject_CallMethod(fileobject, "close", "");
               source_buf = PyBytes_AsString(source_bytes_object);
               code = Py_CompileString(source_buf, filename, Py_file_input);

        * For ‘FrameObject’ objects, the *note f_lasti: 88f. member now
          represents a wordcode offset instead of a simple offset into
          the bytecode string.  This means that this number needs to be
          multiplied by 2 to be used with APIs that expect a byte offset
          instead (like *note PyCode_Addr2Line(): 890. for example).
          Notice as well that the ‘f_lasti’ member of ‘FrameObject’
          objects is not considered stable: please use *note
          PyFrame_GetLineNumber(): 78e. instead.


File: python.info,  Node: CPython bytecode changes<3>,  Next: Build Changes<4>,  Prev: Porting to Python 3 10,  Up: What’s New In Python 3 10

1.4.11 CPython bytecode changes
-------------------------------

   * The ‘MAKE_FUNCTION’ instruction now accepts either a dict or a
     tuple of strings as the function’s annotations.  (Contributed by
     Yurii Karabas and Inada Naoki in bpo-42202(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42202


File: python.info,  Node: Build Changes<4>,  Next: C API Changes<4>,  Prev: CPython bytecode changes<3>,  Up: What’s New In Python 3 10

1.4.12 Build Changes
--------------------

   * PEP 644(1): Python now requires OpenSSL 1.1.1 or newer.  OpenSSL
     1.0.2 is no longer supported.  (Contributed by Christian Heimes in
     bpo-43669(2).)

   * The C99 functions ‘snprintf()’ and ‘vsnprintf()’ are now required
     to build Python.  (Contributed by Victor Stinner in bpo-36020(3).)

   * *note sqlite3: cf. requires SQLite 3.7.15 or higher.  (Contributed
     by Sergey Fedoseev and Erlend E. Aasland in bpo-40744(4) and
     bpo-40810(5).)

   * The *note atexit: c. module must now always be built as a built-in
     module.  (Contributed by Victor Stinner in bpo-42639(6).)

   * Add *note -disable-test-modules: 893. option to the ‘configure’
     script: don’t build nor install test modules.  (Contributed by
     Xavier de Gaye, Thomas Petazzoni and Peixing Xin in bpo-27640(7).)

   * Add *note -with-wheel-pkg-dir=PATH option: 894. to the
     ‘./configure’ script.  If specified, the *note ensurepip: 55.
     module looks for ‘setuptools’ and ‘pip’ wheel packages in this
     directory: if both are present, these wheel packages are used
     instead of ensurepip bundled wheel packages.

     Some Linux distribution packaging policies recommend against
     bundling dependencies.  For example, Fedora installs wheel packages
     in the ‘/usr/share/python-wheels/’ directory and don’t install the
     ‘ensurepip._bundled’ package.

     (Contributed by Victor Stinner in bpo-42856(8).)

   * Add a new *note configure -without-static-libpython option: 895. to
     not build the ‘libpythonMAJOR.MINOR.a’ static library and not
     install the ‘python.o’ object file.

     (Contributed by Victor Stinner in bpo-43103(9).)

   * The ‘configure’ script now uses the ‘pkg-config’ utility, if
     available, to detect the location of Tcl/Tk headers and libraries.
     As before, those locations can be explicitly specified with the
     ‘--with-tcltk-includes’ and ‘--with-tcltk-libs’ configuration
     options.  (Contributed by Manolis Stamatogiannakis in
     bpo-42603(10).)

   * Add *note -with-openssl-rpath: 896. option to ‘configure’ script.
     The option simplifies building Python with a custom OpenSSL
     installation, e.g.  ‘./configure --with-openssl=/path/to/openssl
     --with-openssl-rpath=auto’.  (Contributed by Christian Heimes in
     bpo-43466(11).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0644/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43669

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36020

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40744

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40810

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42639

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27640

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42856

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43103

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42603

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43466


File: python.info,  Node: C API Changes<4>,  Next: Notable security feature in 3 10 7,  Prev: Build Changes<4>,  Up: What’s New In Python 3 10

1.4.13 C API Changes
--------------------

* Menu:

* PEP 652; Maintaining the Stable ABI: PEP 652 Maintaining the Stable ABI.
* New Features: New Features<8>.
* Porting to Python 3.10: Porting to Python 3 10<2>.
* Deprecated: Deprecated<6>.
* Removed: Removed<6>.


File: python.info,  Node: PEP 652 Maintaining the Stable ABI,  Next: New Features<8>,  Up: C API Changes<4>

1.4.13.1 PEP 652: Maintaining the Stable ABI
............................................

The Stable ABI (Application Binary Interface) for extension modules or
embedding Python is now explicitly defined.  *note C API Stability: 556.
describes C API and ABI stability guarantees along with best practices
for using the Stable ABI.

(Contributed by Petr Viktorin in PEP 652(1) and bpo-43795(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0652/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43795


File: python.info,  Node: New Features<8>,  Next: Porting to Python 3 10<2>,  Prev: PEP 652 Maintaining the Stable ABI,  Up: C API Changes<4>

1.4.13.2 New Features
.....................

   * The result of *note PyNumber_Index(): 89a. now always has exact
     type *note int: 257.  Previously, the result could have been an
     instance of a subclass of ‘int’.  (Contributed by Serhiy Storchaka
     in bpo-40792(1).)

   * Add a new *note orig_argv: 89b. member to the *note PyConfig: 3a9.
     structure: the list of the original command line arguments passed
     to the Python executable.  (Contributed by Victor Stinner in
     bpo-23427(2).)

   * The *note PyDateTime_DATE_GET_TZINFO(): 89c. and *note
     PyDateTime_TIME_GET_TZINFO(): 89d. macros have been added for
     accessing the ‘tzinfo’ attributes of *note datetime.datetime: 1cc.
     and *note datetime.time: 1ce. objects.  (Contributed by Zackery
     Spytz in bpo-30155(3).)

   * Add a *note PyCodec_Unregister(): 89e. function to unregister a
     codec search function.  (Contributed by Hai Shi in bpo-41842(4).)

   * The *note PyIter_Send(): 89f. function was added to allow sending
     value into iterator without raising ‘StopIteration’ exception.
     (Contributed by Vladimir Matveev in bpo-41756(5).)

   * Add *note PyUnicode_AsUTF8AndSize(): 8a0. to the limited C API.
     (Contributed by Alex Gaynor in bpo-41784(6).)

   * Add *note PyModule_AddObjectRef(): 368. function: similar to *note
     PyModule_AddObject(): 369. but don’t steal a reference to the value
     on success.  (Contributed by Victor Stinner in bpo-1635741(7).)

   * Add *note Py_NewRef(): 8a1. and *note Py_XNewRef(): 8a2. functions
     to increment the reference count of an object and return the
     object.  (Contributed by Victor Stinner in bpo-42262(8).)

   * The *note PyType_FromSpecWithBases(): 581. and *note
     PyType_FromModuleAndSpec(): 554. functions now accept a single
     class as the 'bases' argument.  (Contributed by Serhiy Storchaka in
     bpo-42423(9).)

   * The *note PyType_FromModuleAndSpec(): 554. function now accepts
     NULL ‘tp_doc’ slot.  (Contributed by Hai Shi in bpo-41832(10).)

   * The *note PyType_GetSlot(): 8a3. function can accept *note static
     types: 782.  (Contributed by Hai Shi and Petr Viktorin in
     bpo-41073(11).)

   * Add a new *note PySet_CheckExact(): 8a4. function to the C-API to
     check if an object is an instance of *note set: 5dc. but not an
     instance of a subtype.  (Contributed by Pablo Galindo in
     bpo-43277(12).)

   * Add *note PyErr_SetInterruptEx(): 8a5. which allows passing a
     signal number to simulate.  (Contributed by Antoine Pitrou in
     bpo-43356(13).)

   * The limited C API is now supported if *note Python is built in
     debug mode: 1f9. (if the ‘Py_DEBUG’ macro is defined).  In the
     limited C API, the *note Py_INCREF(): 571. and *note Py_DECREF():
     572. functions are now implemented as opaque function calls, rather
     than accessing directly the *note PyObject.ob_refcnt: 8a6. member,
     if Python is built in debug mode and the ‘Py_LIMITED_API’ macro
     targets Python 3.10 or newer.  It became possible to support the
     limited C API in debug mode because the *note PyObject: 33a.
     structure is the same in release and debug mode since Python 3.8
     (see bpo-36465(14)).

     The limited C API is still not supported in the *note
     -with-trace-refs: 398. special build (‘Py_TRACE_REFS’ macro).
     (Contributed by Victor Stinner in bpo-43688(15).)

   * Add the *note Py_Is(x, y): 8a7. function to test if the 'x' object
     is the 'y' object, the same as ‘x is y’ in Python.  Add also the
     *note Py_IsNone(): 8a8, *note Py_IsTrue(): 8a9, *note Py_IsFalse():
     8aa. functions to test if an object is, respectively, the ‘None’
     singleton, the ‘True’ singleton or the ‘False’ singleton.
     (Contributed by Victor Stinner in bpo-43753(16).)

   * Add new functions to control the garbage collector from C code:
     *note PyGC_Enable(): 8ab, *note PyGC_Disable(): 8ac, *note
     PyGC_IsEnabled(): 8ad.  These functions allow to activate,
     deactivate and query the state of the garbage collector from C code
     without having to import the *note gc: 60. module.

   * Add a new *note Py_TPFLAGS_DISALLOW_INSTANTIATION: 585. type flag
     to disallow creating type instances.  (Contributed by Victor
     Stinner in bpo-43916(17).)

   * Add a new *note Py_TPFLAGS_IMMUTABLETYPE: 3c5. type flag for
     creating immutable type objects: type attributes cannot be set nor
     deleted.  (Contributed by Victor Stinner and Erlend E. Aasland in
     bpo-43908(18).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40792

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23427

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30155

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41842

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41756

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41784

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42262

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42423

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41832

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41073

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43277

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43356

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36465

   (15) https://bugs.python.org/issue?@action=redirect&bpo=43688

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43753

   (17) https://bugs.python.org/issue?@action=redirect&bpo=43916

   (18) https://bugs.python.org/issue?@action=redirect&bpo=43908


File: python.info,  Node: Porting to Python 3 10<2>,  Next: Deprecated<6>,  Prev: New Features<8>,  Up: C API Changes<4>

1.4.13.3 Porting to Python 3.10
...............................

   * The ‘PY_SSIZE_T_CLEAN’ macro must now be defined to use *note
     PyArg_ParseTuple(): 574. and *note Py_BuildValue(): 8af. formats
     which use ‘#’: ‘es#’, ‘et#’, ‘s#’, ‘u#’, ‘y#’, ‘z#’, ‘U#’ and ‘Z#’.
     See *note Parsing arguments and building values: 8b0. and PEP
     353(1).  (Contributed by Victor Stinner in bpo-40943(2).)

   * Since *note Py_REFCNT(): 8b1. is changed to the inline static
     function, ‘Py_REFCNT(obj) = new_refcnt’ must be replaced with
     ‘Py_SET_REFCNT(obj, new_refcnt)’: see *note Py_SET_REFCNT(): 8b2.
     (available since Python 3.9).  For backward compatibility, this
     macro can be used:

          #if PY_VERSION_HEX < 0x030900A4
          #  define Py_SET_REFCNT(obj, refcnt) ((Py_REFCNT(obj) = (refcnt)), (void)0)
          #endif

     (Contributed by Victor Stinner in bpo-39573(3).)

   * Calling *note PyDict_GetItem(): 38a. without *note GIL: 159. held
     had been allowed for historical reason.  It is no longer allowed.
     (Contributed by Victor Stinner in bpo-40839(4).)

   * ‘PyUnicode_FromUnicode(NULL, size)’ and
     ‘PyUnicode_FromStringAndSize(NULL, size)’ raise
     ‘DeprecationWarning’ now.  Use *note PyUnicode_New(): 8b3. to
     allocate Unicode object without initial data.  (Contributed by
     Inada Naoki in bpo-36346(5).)

   * The private ‘_PyUnicode_Name_CAPI’ structure of the PyCapsule API
     ‘unicodedata.ucnhash_CAPI’ has been moved to the internal C API.
     (Contributed by Victor Stinner in bpo-42157(6).)

   * *note Py_GetPath(): 3b6, *note Py_GetPrefix(): 3b8, *note
     Py_GetExecPrefix(): 3b4, *note Py_GetProgramFullPath(): 3ba, *note
     Py_GetPythonHome(): 3bd. and *note Py_GetProgramName(): 3bc.
     functions now return ‘NULL’ if called before *note Py_Initialize():
     8b4. (before Python is initialized).  Use the new *note Python
     Initialization Configuration: 3aa. API to get the *note Python Path
     Configuration: 8b5.  (Contributed by Victor Stinner in
     bpo-42260(7).)

   * *note PyList_SET_ITEM(): 391, *note PyTuple_SET_ITEM(): 390. and
     *note PyCell_SET(): 8b6. macros can no longer be used as l-value or
     r-value.  For example, ‘x = PyList_SET_ITEM(a, b, c)’ and
     ‘PyList_SET_ITEM(a, b, c) = x’ now fail with a compiler error.  It
     prevents bugs like ‘if (PyList_SET_ITEM (a, b, c) < 0) ...’ test.
     (Contributed by Zackery Spytz and Victor Stinner in bpo-30459(8).)

   * The non-limited API files ‘odictobject.h’, ‘parser_interface.h’,
     ‘picklebufobject.h’, ‘pyarena.h’, ‘pyctype.h’, ‘pydebug.h’,
     ‘pyfpe.h’, and ‘pytime.h’ have been moved to the ‘Include/cpython’
     directory.  These files must not be included directly, as they are
     already included in ‘Python.h’; see *note Include Files: 787.  If
     they have been included directly, consider including ‘Python.h’
     instead.  (Contributed by Nicholas Sim in bpo-35134(9).)

   * Use the *note Py_TPFLAGS_IMMUTABLETYPE: 3c5. type flag to create
     immutable type objects.  Do not rely on *note Py_TPFLAGS_HEAPTYPE:
     8b7. to decide if a type object is mutable or not; check if
     ‘Py_TPFLAGS_IMMUTABLETYPE’ is set instead.  (Contributed by Victor
     Stinner and Erlend E. Aasland in bpo-43908(10).)

   * The undocumented function ‘Py_FrozenMain’ has been removed from the
     limited API. The function is mainly useful for custom builds of
     Python.  (Contributed by Petr Viktorin in bpo-26241(11).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0353/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40943

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40839

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42157

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42260

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30459

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43908

   (11) https://bugs.python.org/issue?@action=redirect&bpo=26241


File: python.info,  Node: Deprecated<6>,  Next: Removed<6>,  Prev: Porting to Python 3 10<2>,  Up: C API Changes<4>

1.4.13.4 Deprecated
...................

   * The ‘PyUnicode_InternImmortal()’ function is now deprecated and
     will be removed in Python 3.12: use *note
     PyUnicode_InternInPlace(): 8b9. instead.  (Contributed by Victor
     Stinner in bpo-41692(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41692


File: python.info,  Node: Removed<6>,  Prev: Deprecated<6>,  Up: C API Changes<4>

1.4.13.5 Removed
................

   * Removed ‘Py_UNICODE_str*’ functions manipulating ‘Py_UNICODE*’
     strings.  (Contributed by Inada Naoki in bpo-41123(1).)

        * ‘Py_UNICODE_strlen’: use *note PyUnicode_GetLength(): 8bb. or
          *note PyUnicode_GET_LENGTH: 8bc.

        * ‘Py_UNICODE_strcat’: use *note PyUnicode_CopyCharacters():
          8bd. or *note PyUnicode_FromFormat(): 38d.

        * ‘Py_UNICODE_strcpy’, ‘Py_UNICODE_strncpy’: use *note
          PyUnicode_CopyCharacters(): 8bd. or *note
          PyUnicode_Substring(): 8be.

        * ‘Py_UNICODE_strcmp’: use *note PyUnicode_Compare(): 8bf.

        * ‘Py_UNICODE_strncmp’: use *note PyUnicode_Tailmatch(): 8c0.

        * ‘Py_UNICODE_strchr’, ‘Py_UNICODE_strrchr’: use *note
          PyUnicode_FindChar(): 8c1.

   * Removed ‘PyUnicode_GetMax()’.  Please migrate to new ( PEP 393(2))
     APIs.  (Contributed by Inada Naoki in bpo-41103(3).)

   * Removed ‘PyLong_FromUnicode()’.  Please migrate to *note
     PyLong_FromUnicodeObject(): 8c2.  (Contributed by Inada Naoki in
     bpo-41103(4).)

   * Removed ‘PyUnicode_AsUnicodeCopy()’.  Please use *note
     PyUnicode_AsUCS4Copy(): 8c3. or *note PyUnicode_AsWideCharString():
     8c4. (Contributed by Inada Naoki in bpo-41103(5).)

   * Removed ‘_Py_CheckRecursionLimit’ variable: it has been replaced by
     ‘ceval.recursion_limit’ of the *note PyInterpreterState: 8c5.
     structure.  (Contributed by Victor Stinner in bpo-41834(6).)

   * Removed undocumented macros ‘Py_ALLOW_RECURSION’ and
     ‘Py_END_ALLOW_RECURSION’ and the ‘recursion_critical’ field of the
     *note PyInterpreterState: 8c5. structure.  (Contributed by Serhiy
     Storchaka in bpo-41936(7).)

   * Removed the undocumented ‘PyOS_InitInterrupts()’ function.
     Initializing Python already implicitly installs signal handlers:
     see *note PyConfig.install_signal_handlers: 8c6.  (Contributed by
     Victor Stinner in bpo-41713(8).)

   * Remove the ‘PyAST_Validate()’ function.  It is no longer possible
     to build a AST object (‘mod_ty’ type) with the public C API. The
     function was already excluded from the limited C API ( PEP 384(9)).
     (Contributed by Victor Stinner in bpo-43244(10).)

   * Remove the ‘symtable.h’ header file and the undocumented functions:

        * ‘PyST_GetScope()’

        * ‘PySymtable_Build()’

        * ‘PySymtable_BuildObject()’

        * ‘PySymtable_Free()’

        * ‘Py_SymtableString()’

        * ‘Py_SymtableStringObject()’

     The ‘Py_SymtableString()’ function was part the stable ABI by
     mistake but it could not be used, because the ‘symtable.h’ header
     file was excluded from the limited C API.

     Use Python *note symtable: d8. module instead.  (Contributed by
     Victor Stinner in bpo-43244(11).)

   * Remove *note PyOS_ReadlineFunctionPointer(): 589. from the limited
     C API headers and from ‘python3.dll’, the library that provides the
     stable ABI on Windows.  Since the function takes a ‘FILE*’
     argument, its ABI stability cannot be guaranteed.  (Contributed by
     Petr Viktorin in bpo-43868(12).)

   * Remove ‘ast.h’, ‘asdl.h’, and ‘Python-ast.h’ header files.  These
     functions were undocumented and excluded from the limited C API.
     Most names defined by these header files were not prefixed by ‘Py’
     and so could create names conflicts.  For example, ‘Python-ast.h’
     defined a ‘Yield’ macro which was conflict with the ‘Yield’ name
     used by the Windows ‘<winbase.h>’ header.  Use the Python *note
     ast: 8. module instead.  (Contributed by Victor Stinner in
     bpo-43244(13).)

   * Remove the compiler and parser functions using ‘struct _mod’ type,
     because the public AST C API was removed:

        * ‘PyAST_Compile()’

        * ‘PyAST_CompileEx()’

        * ‘PyAST_CompileObject()’

        * ‘PyFuture_FromAST()’

        * ‘PyFuture_FromASTObject()’

        * ‘PyParser_ASTFromFile()’

        * ‘PyParser_ASTFromFileObject()’

        * ‘PyParser_ASTFromFilename()’

        * ‘PyParser_ASTFromString()’

        * ‘PyParser_ASTFromStringObject()’

     These functions were undocumented and excluded from the limited C
     API. (Contributed by Victor Stinner in bpo-43244(14).)

   * Remove the ‘pyarena.h’ header file with functions:

        * ‘PyArena_New()’

        * ‘PyArena_Free()’

        * ‘PyArena_Malloc()’

        * ‘PyArena_AddPyObject()’

     These functions were undocumented, excluded from the limited C API,
     and were only used internally by the compiler.  (Contributed by
     Victor Stinner in bpo-43244(15).)

   * The ‘PyThreadState.use_tracing’ member has been removed to optimize
     Python.  (Contributed by Mark Shannon in bpo-43760(16).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (2) https://peps.python.org/pep-0393/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41103

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41103

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41103

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41834

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41936

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41713

   (9) https://peps.python.org/pep-0384/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43868

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (15) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43760


File: python.info,  Node: Notable security feature in 3 10 7,  Next: Notable security feature in 3 10 8,  Prev: C API Changes<4>,  Up: What’s New In Python 3 10

1.4.14 Notable security feature in 3.10.7
-----------------------------------------

Converting between *note int: 257. and *note str: 44f. in bases other
than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10
(decimal) now raises a *note ValueError: 202. if the number of digits in
string form is above a limit to avoid potential denial of service
attacks due to the algorithmic complexity.  This is a mitigation for CVE
2020-10735(1).  This limit can be configured or disabled by environment
variable, command line flag, or *note sys: d9. APIs.  See the *note
integer string conversion length limitation: 5f8. documentation.  The
default limit is 4300 digits in string form.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: Notable security feature in 3 10 8,  Next: Notable changes in 3 10 12,  Prev: Notable security feature in 3 10 7,  Up: What’s New In Python 3 10

1.4.15 Notable security feature in 3.10.8
-----------------------------------------

The deprecated ‘mailcap’ module now refuses to inject unsafe text
(filenames, MIME types, parameters) into shell commands.  Instead of
using such text, it will warn and act as if a match was not found (or
for test commands, as if the test failed).  (Contributed by Petr
Viktorin in gh-98966(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98966


File: python.info,  Node: Notable changes in 3 10 12,  Prev: Notable security feature in 3 10 8,  Up: What’s New In Python 3 10

1.4.16 Notable changes in 3.10.12
---------------------------------

* Menu:

* tarfile: tarfile<3>.


File: python.info,  Node: tarfile<3>,  Up: Notable changes in 3 10 12

1.4.16.1 tarfile
................

   * The extraction methods in *note tarfile: de, and *note
     shutil.unpack_archive(): 46e, have a new a 'filter' argument that
     allows limiting tar features than may be surprising or dangerous,
     such as creating files outside the destination directory.  See
     *note Extraction filters: 46f. for details.  In Python 3.12, use
     without the 'filter' argument will show a *note DeprecationWarning:
     1a5.  In Python 3.14, the default will switch to ‘'data'’.
     (Contributed by Petr Viktorin in PEP 706(1).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0706/


File: python.info,  Node: What’s New In Python 3 9,  Next: What’s New In Python 3 8,  Prev: What’s New In Python 3 10,  Up: What’s New in Python

1.5 What’s New In Python 3.9
============================


Editor: Łukasz Langa

This article explains the new features in Python 3.9, compared to 3.8.
Python 3.9 was released on October 5, 2020.  For full details, see the
*note changelog: 13c.

See also
........

PEP 596(1) - Python 3.9 Release Schedule

* Menu:

* Summary – Release highlights: Summary – Release highlights<4>.
* You should check for DeprecationWarning in your code::
* New Features: New Features<9>.
* Other Language Changes: Other Language Changes<5>.
* New Modules: New Modules<5>.
* Improved Modules: Improved Modules<5>.
* Optimizations: Optimizations<5>.
* Deprecated: Deprecated<7>.
* Removed: Removed<7>.
* Porting to Python 3.9: Porting to Python 3 9.
* Build Changes: Build Changes<5>.
* C API Changes: C API Changes<5>.
* Notable changes in Python 3.9.1: Notable changes in Python 3 9 1.
* Notable changes in Python 3.9.2: Notable changes in Python 3 9 2.
* Notable changes in Python 3.9.3: Notable changes in Python 3 9 3.
* Notable changes in Python 3.9.5: Notable changes in Python 3 9 5.
* Notable security feature in 3.9.14: Notable security feature in 3 9 14.
* Notable changes in 3.9.17: Notable changes in 3 9 17.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0596/


File: python.info,  Node: Summary – Release highlights<4>,  Next: You should check for DeprecationWarning in your code,  Up: What’s New In Python 3 9

1.5.1 Summary – Release highlights
----------------------------------

New syntax features:

   * PEP 584(1), union operators added to ‘dict’;

   * PEP 585(2), type hinting generics in standard collections;

   * PEP 614(3), relaxed grammar restrictions on decorators.

New built-in features:

   * PEP 616(4), string methods to remove prefixes and suffixes.

New features in the standard library:

   * PEP 593(5), flexible function and variable annotations;

   * *note os.pidfd_open(): 47d. added that allows process management
     without races and signals.

Interpreter improvements:

   * PEP 573(6), fast access to module state from methods of C extension
     types;

   * PEP 617(7), CPython now uses a new parser based on PEG;

   * a number of Python builtins (range, tuple, set, frozenset, list,
     dict) are now sped up using PEP 590(8) vectorcall;

   * garbage collection does not block on resurrected objects;

   * a number of Python modules (‘_abc’, ‘audioop’, ‘_bz2’, ‘_codecs’,
     ‘_contextvars’, ‘_crypt’, ‘_functools’, ‘_json’, ‘_locale’, *note
     math: 8e, *note operator: 9f, *note resource: bc, *note time: ee,
     ‘_weakref’) now use multiphase initialization as defined by PEP
     489;

   * a number of standard library modules (‘audioop’, *note ast: 8,
     *note grp: 66, ‘_hashlib’, *note pwd: b2, ‘_posixsubprocess’, *note
     random: b8, *note select: c1, *note struct: d5, *note termios: e1,
     *note zlib: 133.) are now using the stable ABI defined by PEP 384.

New library modules:

   * PEP 615(9), the IANA Time Zone Database is now present in the
     standard library in the *note zoneinfo: 134. module;

   * an implementation of a topological sort of a graph is now provided
     in the new *note graphlib: 65. module.

Release process changes:

   * PEP 602(10), CPython adopts an annual release cycle.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0584/

   (2) https://peps.python.org/pep-0585/

   (3) https://peps.python.org/pep-0614/

   (4) https://peps.python.org/pep-0616/

   (5) https://peps.python.org/pep-0593/

   (6) https://peps.python.org/pep-0573/

   (7) https://peps.python.org/pep-0617/

   (8) https://peps.python.org/pep-0590/

   (9) https://peps.python.org/pep-0615/

   (10) https://peps.python.org/pep-0602/


File: python.info,  Node: You should check for DeprecationWarning in your code,  Next: New Features<9>,  Prev: Summary – Release highlights<4>,  Up: What’s New In Python 3 9

1.5.2 You should check for DeprecationWarning in your code
----------------------------------------------------------

When Python 2.7 was still supported, a lot of functionality in Python 3
was kept for backward compatibility with Python 2.7.  With the end of
Python 2 support, these backward compatibility layers have been removed,
or will be removed soon.  Most of them emitted a *note
DeprecationWarning: 1a5. warning for several years.  For example, using
‘collections.Mapping’ instead of ‘collections.abc.Mapping’ emits a
‘DeprecationWarning’ since Python 3.3, released in 2012.

Test your application with the *note -W: 8d0. ‘default’ command-line
option to see *note DeprecationWarning: 1a5. and *note
PendingDeprecationWarning: 8d1, or even with ‘-W’ ‘error’ to treat them
as errors.  *note Warnings Filter: 8d2. can be used to ignore warnings
from third-party code.

Python 3.9 is the last version providing those Python 2 backward
compatibility layers, to give more time to Python projects maintainers
to organize the removal of the Python 2 support and add support for
Python 3.9.

Aliases to *note Abstract Base Classes: 87f. in the *note collections:
1d. module, like ‘collections.Mapping’ alias to *note
collections.abc.Mapping: 8d3, are kept for one last release for backward
compatibility.  They will be removed from Python 3.10.

More generally, try to run your tests in the *note Python Development
Mode: 1f8. which helps to prepare your code to make it compatible with
the next Python version.

Note: a number of pre-existing deprecations were removed in this version
of Python as well.  Consult the *note Removed: 8d4. section.


File: python.info,  Node: New Features<9>,  Next: Other Language Changes<5>,  Prev: You should check for DeprecationWarning in your code,  Up: What’s New In Python 3 9

1.5.3 New Features
------------------

* Menu:

* Dictionary Merge & Update Operators::
* New String Methods to Remove Prefixes and Suffixes::
* Type Hinting Generics in Standard Collections::
* New Parser::


File: python.info,  Node: Dictionary Merge & Update Operators,  Next: New String Methods to Remove Prefixes and Suffixes,  Up: New Features<9>

1.5.3.1 Dictionary Merge & Update Operators
...........................................

Merge (‘|’) and update (‘|=’) operators have been added to the built-in
*note dict: 256. class.  Those complement the existing ‘dict.update’ and
‘{**d1, **d2}’ methods of merging dictionaries.

Example:

     >>> x = {"key1": "value1 from x", "key2": "value2 from x"}
     >>> y = {"key2": "value2 from y", "key3": "value3 from y"}
     >>> x | y
     {'key1': 'value1 from x', 'key2': 'value2 from y', 'key3': 'value3 from y'}
     >>> y | x
     {'key2': 'value2 from x', 'key3': 'value3 from y', 'key1': 'value1 from x'}

See PEP 584(1) for a full description.  (Contributed by Brandt Bucher in
bpo-36144(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0584/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36144


File: python.info,  Node: New String Methods to Remove Prefixes and Suffixes,  Next: Type Hinting Generics in Standard Collections,  Prev: Dictionary Merge & Update Operators,  Up: New Features<9>

1.5.3.2 New String Methods to Remove Prefixes and Suffixes
..........................................................

*note str.removeprefix(prefix): 8d8. and *note str.removesuffix(suffix):
8d9. have been added to easily remove an unneeded prefix or a suffix
from a string.  Corresponding ‘bytes’, ‘bytearray’, and
‘collections.UserString’ methods have also been added.  See PEP 616(1)
for a full description.  (Contributed by Dennis Sweeney in
bpo-39939(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0616/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39939


File: python.info,  Node: Type Hinting Generics in Standard Collections,  Next: New Parser,  Prev: New String Methods to Remove Prefixes and Suffixes,  Up: New Features<9>

1.5.3.3 Type Hinting Generics in Standard Collections
.....................................................

In type annotations you can now use built-in collection types such as
‘list’ and ‘dict’ as generic types instead of importing the
corresponding capitalized types (e.g.  ‘List’ or ‘Dict’) from ‘typing’.
Some other types in the standard library are also now generic, for
example ‘queue.Queue’.

Example:

     def greet_all(names: list[str]) -> None:
         for name in names:
             print("Hello", name)

See PEP 585(1) for more details.  (Contributed by Guido van Rossum,
Ethan Smith, and Batuhan Taşkaya in bpo-39481(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39481


File: python.info,  Node: New Parser,  Prev: Type Hinting Generics in Standard Collections,  Up: New Features<9>

1.5.3.4 New Parser
..................

Python 3.9 uses a new parser, based on PEG(1) instead of LL(1)(2).  The
new parser’s performance is roughly comparable to that of the old
parser, but the PEG formalism is more flexible than LL(1) when it comes
to designing new language features.  We’ll start using this flexibility
in Python 3.10 and later.

The *note ast: 8. module uses the new parser and produces the same AST
as the old parser.

In Python 3.10, the old parser will be deleted and so will all
functionality that depends on it (primarily the ‘parser’ module, which
has long been deprecated).  In Python 3.9 'only', you can switch back to
the LL(1) parser using a command line switch (‘-X oldparser’) or an
environment variable (‘PYTHONOLDPARSER=1’).

See PEP 617(3) for more details.  (Contributed by Guido van Rossum,
Pablo Galindo and Lysandros Nikolaou in bpo-40334(4).)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Parsing_expression_grammar

   (2) https://en.wikipedia.org/wiki/LL_parser

   (3) https://peps.python.org/pep-0617/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40334


File: python.info,  Node: Other Language Changes<5>,  Next: New Modules<5>,  Prev: New Features<9>,  Up: What’s New In Python 3 9

1.5.4 Other Language Changes
----------------------------

   * *note __import__(): 8dd. now raises *note ImportError: 41c. instead
     of *note ValueError: 202, which used to occur when a relative
     import went past its top-level package.  (Contributed by Ngalim
     Siregar in bpo-37444(1).)

   * Python now gets the absolute path of the script filename specified
     on the command line (ex: ‘python3 script.py’): the ‘__file__’
     attribute of the *note __main__: 1. module became an absolute path,
     rather than a relative path.  These paths now remain valid after
     the current directory is changed by *note os.chdir(): 610.  As a
     side effect, the traceback also displays the absolute path for
     ‘__main__’ module frames in this case.  (Contributed by Victor
     Stinner in bpo-20443(2).)

   * In the *note Python Development Mode: 1f8. and in *note debug
     build: 1f9, the 'encoding' and 'errors' arguments are now checked
     for string encoding and decoding operations.  Examples: *note
     open(): 51f, *note str.encode(): 8de. and *note bytes.decode():
     8df.

     By default, for best performance, the 'errors' argument is only
     checked at the first encoding/decoding error and the 'encoding'
     argument is sometimes ignored for empty strings.  (Contributed by
     Victor Stinner in bpo-37388(3).)

   * ‘"".replace("", s, n)’ now returns ‘s’ instead of an empty string
     for all non-zero ‘n’.  It is now consistent with ‘"".replace("",
     s)’.  There are similar changes for *note bytes: 1c2. and *note
     bytearray: 2ea. objects.  (Contributed by Serhiy Storchaka in
     bpo-28029(4).)

   * Any valid expression can now be used as a *note decorator: 734.
     Previously, the grammar was much more restrictive.  See PEP 614(5)
     for details.  (Contributed by Brandt Bucher in bpo-39702(6).)

   * Improved help for the *note typing: 104. module.  Docstrings are
     now shown for all special forms and special generic aliases (like
     ‘Union’ and ‘List’).  Using *note help(): 8e0. with generic alias
     like ‘List[int]’ will show the help for the correspondent concrete
     type (‘list’ in this case).  (Contributed by Serhiy Storchaka in
     bpo-40257(7).)

   * Parallel running of *note aclose(): 8e1. / *note asend(): 8e2. /
     *note athrow(): 4fc. is now prohibited, and ‘ag_running’ now
     reflects the actual running status of the async generator.
     (Contributed by Yury Selivanov in bpo-30773(8).)

   * Unexpected errors in calling the ‘__iter__’ method are no longer
     masked by ‘TypeError’ in the *note in: 2f4. operator and functions
     *note contains(): 8e3, *note indexOf(): 8e4. and *note countOf():
     8e5. of the *note operator: 9f. module.  (Contributed by Serhiy
     Storchaka in bpo-40824(9).)

   * Unparenthesized lambda expressions can no longer be the expression
     part in an ‘if’ clause in comprehensions and generator expressions.
     See bpo-41848(10) and bpo-43755(11) for details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37444

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20443

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37388

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28029

   (5) https://peps.python.org/pep-0614/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39702

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40257

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30773

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40824

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41848

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43755


File: python.info,  Node: New Modules<5>,  Next: Improved Modules<5>,  Prev: Other Language Changes<5>,  Up: What’s New In Python 3 9

1.5.5 New Modules
-----------------

* Menu:

* zoneinfo::
* graphlib::


File: python.info,  Node: zoneinfo,  Next: graphlib,  Up: New Modules<5>

1.5.5.1 zoneinfo
................

The *note zoneinfo: 134. module brings support for the IANA time zone
database to the standard library.  It adds *note zoneinfo.ZoneInfo: 8e8,
a concrete *note datetime.tzinfo: 5e1. implementation backed by the
system’s time zone data.

Example:

     >>> from zoneinfo import ZoneInfo
     >>> import datetime as dt

     >>> # Daylight saving time
     >>> when = dt.datetime(2020, 10, 31, 12, tzinfo=ZoneInfo("America/Los_Angeles"))
     >>> print(when)
     2020-10-31 12:00:00-07:00
     >>> when.tzname()
     'PDT'

     >>> # Standard time
     >>> when += dt.timedelta(days=7)
     >>> print(when)
     2020-11-07 12:00:00-08:00
     >>> print(when.tzname())
     PST

As a fall-back source of data for platforms that don’t ship the IANA
database, the tzdata(1) module was released as a first-party package –
distributed via PyPI and maintained by the CPython core team.

See also
........

PEP 615(2) – Support for the IANA Time Zone Database in the Standard Library

     PEP written and implemented by Paul Ganssle

   ---------- Footnotes ----------

   (1) https://pypi.org/project/tzdata/

   (2) https://peps.python.org/pep-0615/


File: python.info,  Node: graphlib,  Prev: zoneinfo,  Up: New Modules<5>

1.5.5.2 graphlib
................

A new module, *note graphlib: 65, was added that contains the *note
graphlib.TopologicalSorter: 8ea. class to offer functionality to perform
topological sorting of graphs.  (Contributed by Pablo Galindo, Tim
Peters and Larry Hastings in bpo-17005(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17005


File: python.info,  Node: Improved Modules<5>,  Next: Optimizations<5>,  Prev: New Modules<5>,  Up: What’s New In Python 3 9

1.5.6 Improved Modules
----------------------

* Menu:

* ast: ast<2>.
* asyncio: asyncio<5>.
* compileall: compileall<2>.
* concurrent.futures: concurrent futures<2>.
* curses: curses<2>.
* datetime: datetime<2>.
* distutils: distutils<3>.
* fcntl: fcntl<2>.
* ftplib: ftplib<2>.
* gc: gc<2>.
* hashlib: hashlib<4>.
* http::
* IDLE and idlelib: IDLE and idlelib<3>.
* imaplib::
* importlib: importlib<3>.
* inspect: inspect<4>.
* ipaddress: ipaddress<2>.
* math: math<4>.
* multiprocessing: multiprocessing<2>.
* nntplib::
* os: os<5>.
* pathlib: pathlib<6>.
* pdb: pdb<3>.
* poplib::
* pprint: pprint<2>.
* pydoc::
* random: random<3>.
* signal::
* smtplib::
* socket: socket<3>.
* time: time<3>.
* sys: sys<6>.
* tracemalloc::
* typing: typing<6>.
* unicodedata: unicodedata<4>.
* venv: venv<3>.
* xml: xml<3>.


File: python.info,  Node: ast<2>,  Next: asyncio<5>,  Up: Improved Modules<5>

1.5.6.1 ast
...........

Added the 'indent' option to *note dump(): 8ed. which allows it to
produce a multiline indented output.  (Contributed by Serhiy Storchaka
in bpo-37995(1).)

Added *note ast.unparse(): 8ee. as a function in the *note ast: 8.
module that can be used to unparse an *note ast.AST: 1a6. object and
produce a string with code that would produce an equivalent ‘ast.AST’
object when parsed.  (Contributed by Pablo Galindo and Batuhan Taskaya
in bpo-38870(2).)

Added docstrings to AST nodes that contains the ASDL signature used to
construct that node.  (Contributed by Batuhan Taskaya in bpo-39638(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37995

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38870

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39638


File: python.info,  Node: asyncio<5>,  Next: compileall<2>,  Prev: ast<2>,  Up: Improved Modules<5>

1.5.6.2 asyncio
...............

Due to significant security concerns, the 'reuse_address' parameter of
*note asyncio.loop.create_datagram_endpoint(): 736. is no longer
supported.  This is because of the behavior of the socket option
‘SO_REUSEADDR’ in UDP. For more details, see the documentation for
‘loop.create_datagram_endpoint()’.  (Contributed by Kyle Stanley,
Antoine Pitrou, and Yury Selivanov in bpo-37228(1).)

Added a new *note coroutine: 494. *note shutdown_default_executor():
8f0. that schedules a shutdown for the default executor that waits on
the *note ThreadPoolExecutor: 745. to finish closing.  Also, *note
asyncio.run(): 47f. has been updated to use the new coroutine.
(Contributed by Kyle Stanley in bpo-34037(2).)

Added *note asyncio.PidfdChildWatcher: 47c, a Linux-specific child
watcher implementation that polls process file descriptors.
(bpo-38692(3))

Added a new *note coroutine: 494. *note asyncio.to_thread(): 8f1.  It is
mainly used for running IO-bound functions in a separate thread to avoid
blocking the event loop, and essentially works as a high-level version
of *note run_in_executor(): 8f2. that can directly take keyword
arguments.  (Contributed by Kyle Stanley and Yury Selivanov in
bpo-32309(4).)

When cancelling the task due to a timeout, *note asyncio.wait_for():
602. will now wait until the cancellation is complete also in the case
when 'timeout' is <= 0, like it does with positive timeouts.
(Contributed by Elvis Pranskevichus in bpo-32751(5).)

*note asyncio: a. now raises *note TypeError: 2c3. when calling
incompatible methods with an *note ssl.SSLSocket: 8f3. socket.
(Contributed by Ido Michael in bpo-37404(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37228

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34037

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38692

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32309

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32751

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37404


File: python.info,  Node: compileall<2>,  Next: concurrent futures<2>,  Prev: asyncio<5>,  Up: Improved Modules<5>

1.5.6.3 compileall
..................

Added new possibility to use hardlinks for duplicated ‘.pyc’ files:
'hardlink_dupes' parameter and –hardlink-dupes command line option.
(Contributed by Lumír ‘Frenzy’ Balhar in bpo-40495(1).)

Added new options for path manipulation in resulting ‘.pyc’ files:
'stripdir', 'prependdir', 'limit_sl_dest' parameters and -s, -p, -e
command line options.  Added the possibility to specify the option for
an optimization level multiple times.  (Contributed by Lumír ‘Frenzy’
Balhar in bpo-38112(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40495

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38112


File: python.info,  Node: concurrent futures<2>,  Next: curses<2>,  Prev: compileall<2>,  Up: Improved Modules<5>

1.5.6.4 concurrent.futures
..........................

Added a new 'cancel_futures' parameter to *note
concurrent.futures.Executor.shutdown(): 8f6. that cancels all pending
futures which have not started running, instead of waiting for them to
complete before shutting down the executor.  (Contributed by Kyle
Stanley in bpo-39349(1).)

Removed daemon threads from *note ThreadPoolExecutor: 745. and *note
ProcessPoolExecutor: 8f7.  This improves compatibility with
subinterpreters and predictability in their shutdown processes.
(Contributed by Kyle Stanley in bpo-39812(2).)

Workers in *note ProcessPoolExecutor: 8f7. are now spawned on demand,
only when there are no available idle workers to reuse.  This optimizes
startup overhead and reduces the amount of lost CPU time to idle
workers.  (Contributed by Kyle Stanley in bpo-39207(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39349

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39812

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39207


File: python.info,  Node: curses<2>,  Next: datetime<2>,  Prev: concurrent futures<2>,  Up: Improved Modules<5>

1.5.6.5 curses
..............

Added *note curses.get_escdelay(): 8f9, *note curses.set_escdelay():
8fa, *note curses.get_tabsize(): 8fb, and *note curses.set_tabsize():
8fc. functions.  (Contributed by Anthony Sottile in bpo-38312(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38312


File: python.info,  Node: datetime<2>,  Next: distutils<3>,  Prev: curses<2>,  Up: Improved Modules<5>

1.5.6.6 datetime
................

The *note isocalendar(): 8fe. of *note datetime.date: 1cd. and *note
isocalendar(): 8ff. of *note datetime.datetime: 1cc. methods now returns
a *note namedtuple(): 1ca. instead of a *note tuple: 373.  (Contributed
by Donghee Na in bpo-24416(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24416


File: python.info,  Node: distutils<3>,  Next: fcntl<2>,  Prev: datetime<2>,  Up: Improved Modules<5>

1.5.6.7 distutils
.................

The ‘upload’ command now creates SHA2-256 and Blake2b-256 hash digests.
It skips MD5 on platforms that block MD5 digest.  (Contributed by
Christian Heimes in bpo-40698(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40698


File: python.info,  Node: fcntl<2>,  Next: ftplib<2>,  Prev: distutils<3>,  Up: Improved Modules<5>

1.5.6.8 fcntl
.............

Added constants ‘fcntl.F_OFD_GETLK’, ‘fcntl.F_OFD_SETLK’ and
‘fcntl.F_OFD_SETLKW’.  (Contributed by Donghee Na in bpo-38602(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38602


File: python.info,  Node: ftplib<2>,  Next: gc<2>,  Prev: fcntl<2>,  Up: Improved Modules<5>

1.5.6.9 ftplib
..............

*note FTP: 903. and *note FTP_TLS: 904. now raise a *note ValueError:
202. if the given timeout for their constructor is zero to prevent the
creation of a non-blocking socket.  (Contributed by Donghee Na in
bpo-39259(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39259


File: python.info,  Node: gc<2>,  Next: hashlib<4>,  Prev: ftplib<2>,  Up: Improved Modules<5>

1.5.6.10 gc
...........

When the garbage collector makes a collection in which some objects
resurrect (they are reachable from outside the isolated cycles after the
finalizers have been executed), do not block the collection of all
objects that are still unreachable.  (Contributed by Pablo Galindo and
Tim Peters in bpo-38379(1).)

Added a new function *note gc.is_finalized(): 906. to check if an object
has been finalized by the garbage collector.  (Contributed by Pablo
Galindo in bpo-39322(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38379

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39322


File: python.info,  Node: hashlib<4>,  Next: http,  Prev: gc<2>,  Up: Improved Modules<5>

1.5.6.11 hashlib
................

The *note hashlib: 68. module can now use SHA3 hashes and SHAKE XOF from
OpenSSL when available.  (Contributed by Christian Heimes in
bpo-37630(1).)

Builtin hash modules can now be disabled with ‘./configure
--without-builtin-hashlib-hashes’ or selectively enabled with e.g.
‘./configure --with-builtin-hashlib-hashes=sha3,blake2’ to force use of
OpenSSL based implementation.  (Contributed by Christian Heimes in
bpo-40479(2))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37630

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40479


File: python.info,  Node: http,  Next: IDLE and idlelib<3>,  Prev: hashlib<4>,  Up: Improved Modules<5>

1.5.6.12 http
.............

HTTP status codes ‘103 EARLY_HINTS’, ‘418 IM_A_TEAPOT’ and ‘425
TOO_EARLY’ are added to *note http.HTTPStatus: 909.  (Contributed by
Donghee Na in bpo-39509(1) and Ross Rhodes in bpo-39507(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39509

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39507


File: python.info,  Node: IDLE and idlelib<3>,  Next: imaplib,  Prev: http,  Up: Improved Modules<5>

1.5.6.13 IDLE and idlelib
.........................

Added option to toggle cursor blink off.  (Contributed by Zackery Spytz
in bpo-4603(1).)

Escape key now closes IDLE completion windows.  (Contributed by Johnny
Najera in bpo-38944(2).)

Added keywords to module name completion list.  (Contributed by Terry J.
Reedy in bpo-37765(3).)

New in 3.9 maintenance releases

Make IDLE invoke *note sys.excepthook(): 811. (when started without
‘-n’).  User hooks were previously ignored.  (Contributed by Ken Hilton
in bpo-43008(4).)

The changes above have been backported to 3.8 maintenance releases.

Rearrange the settings dialog.  Split the General tab into Windows and
Shell/Ed tabs.  Move help sources, which extend the Help menu, to the
Extensions tab.  Make space for new options and shorten the dialog.  The
latter makes the dialog better fit small screens.  (Contributed by Terry
Jan Reedy in bpo-40468(5).)  Move the indent space setting from the Font
tab to the new Windows tab.  (Contributed by Mark Roseman and Terry Jan
Reedy in bpo-33962(6).)

Apply syntax highlighting to ‘.pyi’ files.  (Contributed by Alex Waygood
and Terry Jan Reedy in bpo-45447(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4603

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38944

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37765

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43008

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40468

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33962

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45447


File: python.info,  Node: imaplib,  Next: importlib<3>,  Prev: IDLE and idlelib<3>,  Up: Improved Modules<5>

1.5.6.14 imaplib
................

*note IMAP4: 90c. and *note IMAP4_SSL: 90d. now have an optional
'timeout' parameter for their constructors.  Also, the *note open():
90e. method now has an optional 'timeout' parameter with this change.
The overridden methods of ‘IMAP4_SSL’ and *note IMAP4_stream: 90f. were
applied to this change.  (Contributed by Donghee Na in bpo-38615(1).)

*note imaplib.IMAP4.unselect(): 910. is added.
‘imaplib.IMAP4.unselect()’ frees server’s resources associated with the
selected mailbox and returns the server to the authenticated state.
This command performs the same actions as *note imaplib.IMAP4.close():
911, except that no messages are permanently removed from the currently
selected mailbox.  (Contributed by Donghee Na in bpo-40375(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38615

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40375


File: python.info,  Node: importlib<3>,  Next: inspect<4>,  Prev: imaplib,  Up: Improved Modules<5>

1.5.6.15 importlib
..................

To improve consistency with import statements, *note
importlib.util.resolve_name(): 913. now raises *note ImportError: 41c.
instead of *note ValueError: 202. for invalid relative import attempts.
(Contributed by Ngalim Siregar in bpo-37444(1).)

Import loaders which publish immutable module objects can now publish
immutable packages in addition to individual modules.  (Contributed by
Dino Viehland in bpo-39336(2).)

Added *note importlib.resources.files(): 491. function with support for
subdirectories in package data, matching backport in
‘importlib_resources’ version 1.5.  (Contributed by Jason R. Coombs in
bpo-39791(3).)

Refreshed ‘importlib.metadata’ from ‘importlib_metadata’ version 1.6.1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37444

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39336

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39791


File: python.info,  Node: inspect<4>,  Next: ipaddress<2>,  Prev: importlib<3>,  Up: Improved Modules<5>

1.5.6.16 inspect
................

*note inspect.BoundArguments.arguments: 915. is changed from
‘OrderedDict’ to regular dict.  (Contributed by Inada Naoki in
bpo-36350(1) and bpo-39775(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36350

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39775


File: python.info,  Node: ipaddress<2>,  Next: math<4>,  Prev: inspect<4>,  Up: Improved Modules<5>

1.5.6.17 ipaddress
..................

*note ipaddress: 80. now supports IPv6 Scoped Addresses (IPv6 address
with suffix ‘%<scope_id>’).

Scoped IPv6 addresses can be parsed using *note ipaddress.IPv6Address:
1fd.  If present, scope zone ID is available through the *note scope_id:
917. attribute.  (Contributed by Oleksandr Pavliuk in bpo-34788(1).)

Starting with Python 3.9.5 the *note ipaddress: 80. module no longer
accepts any leading zeros in IPv4 address strings.  (Contributed by
Christian Heimes in bpo-36384(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34788

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36384


File: python.info,  Node: math<4>,  Next: multiprocessing<2>,  Prev: ipaddress<2>,  Up: Improved Modules<5>

1.5.6.18 math
.............

Expanded the *note math.gcd(): 919. function to handle multiple
arguments.  Formerly, it only supported two arguments.  (Contributed by
Serhiy Storchaka in bpo-39648(1).)

Added *note math.lcm(): 91a.: return the least common multiple of
specified arguments.  (Contributed by Mark Dickinson, Ananthakrishnan
and Serhiy Storchaka in bpo-39479(2) and bpo-39648(3).)

Added *note math.nextafter(): 49b.: return the next floating-point value
after 'x' towards 'y'.  (Contributed by Victor Stinner in bpo-39288(4).)

Added *note math.ulp(): 91b.: return the value of the least significant
bit of a float.  (Contributed by Victor Stinner in bpo-39310(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39648

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39479

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39648

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39288

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39310


File: python.info,  Node: multiprocessing<2>,  Next: nntplib,  Prev: math<4>,  Up: Improved Modules<5>

1.5.6.19 multiprocessing
........................

The *note multiprocessing.SimpleQueue: 91d. class has a new *note
close(): 91e. method to explicitly close the queue.  (Contributed by
Victor Stinner in bpo-30966(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30966


File: python.info,  Node: nntplib,  Next: os<5>,  Prev: multiprocessing<2>,  Up: Improved Modules<5>

1.5.6.20 nntplib
................

‘NNTP’ and ‘NNTP_SSL’ now raise a *note ValueError: 202. if the given
timeout for their constructor is zero to prevent the creation of a
non-blocking socket.  (Contributed by Donghee Na in bpo-39259(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39259


File: python.info,  Node: os<5>,  Next: pathlib<6>,  Prev: nntplib,  Up: Improved Modules<5>

1.5.6.21 os
...........

Added *note CLD_KILLED: 921. and *note CLD_STOPPED: 922. for ‘si_code’.
(Contributed by Donghee Na in bpo-38493(1).)

Exposed the Linux-specific *note os.pidfd_open(): 47d. (bpo-38692(2))
and *note os.P_PIDFD: 923. (bpo-38713(3)) for process management with
file descriptors.

The *note os.unsetenv(): 924. function is now also available on Windows.
(Contributed by Victor Stinner in bpo-39413(4).)

The *note os.putenv(): 925. and *note os.unsetenv(): 924. functions are
now always available.  (Contributed by Victor Stinner in bpo-39395(5).)

Added *note os.waitstatus_to_exitcode(): 926. function: convert a wait
status to an exit code.  (Contributed by Victor Stinner in
bpo-40094(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38493

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38692

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38713

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39413

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39395

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40094


File: python.info,  Node: pathlib<6>,  Next: pdb<3>,  Prev: os<5>,  Up: Improved Modules<5>

1.5.6.22 pathlib
................

Added *note pathlib.Path.readlink(): 928. which acts similarly to *note
os.readlink(): 929.  (Contributed by Girts Folkmanis in bpo-30618(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30618


File: python.info,  Node: pdb<3>,  Next: poplib,  Prev: pathlib<6>,  Up: Improved Modules<5>

1.5.6.23 pdb
............

On Windows now *note Pdb: 92b. supports ‘~/.pdbrc’.  (Contributed by Tim
Hopper and Dan Lidral-Porter in bpo-20523(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20523


File: python.info,  Node: poplib,  Next: pprint<2>,  Prev: pdb<3>,  Up: Improved Modules<5>

1.5.6.24 poplib
...............

*note POP3: 92d. and *note POP3_SSL: 92e. now raise a *note ValueError:
202. if the given timeout for their constructor is zero to prevent the
creation of a non-blocking socket.  (Contributed by Donghee Na in
bpo-39259(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39259


File: python.info,  Node: pprint<2>,  Next: pydoc,  Prev: poplib,  Up: Improved Modules<5>

1.5.6.25 pprint
...............

*note pprint: ae. can now pretty-print *note types.SimpleNamespace: 1d1.
(Contributed by Carl Bordum Hansen in bpo-37376(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37376


File: python.info,  Node: pydoc,  Next: random<3>,  Prev: pprint<2>,  Up: Improved Modules<5>

1.5.6.26 pydoc
..............

The documentation string is now shown not only for class, function,
method etc, but for any object that has its own *note __doc__: 931.
attribute.  (Contributed by Serhiy Storchaka in bpo-40257(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40257


File: python.info,  Node: random<3>,  Next: signal,  Prev: pydoc,  Up: Improved Modules<5>

1.5.6.27 random
...............

Added a new *note random.Random.randbytes(): 933. method: generate
random bytes.  (Contributed by Victor Stinner in bpo-40286(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40286


File: python.info,  Node: signal,  Next: smtplib,  Prev: random<3>,  Up: Improved Modules<5>

1.5.6.28 signal
...............

Exposed the Linux-specific *note signal.pidfd_send_signal(): 935. for
sending to signals to a process using a file descriptor instead of a
pid.  (bpo-38712(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38712


File: python.info,  Node: smtplib,  Next: socket<3>,  Prev: signal,  Up: Improved Modules<5>

1.5.6.29 smtplib
................

*note SMTP: 937. and *note SMTP_SSL: 938. now raise a *note ValueError:
202. if the given timeout for their constructor is zero to prevent the
creation of a non-blocking socket.  (Contributed by Donghee Na in
bpo-39259(1).)

*note LMTP: 939. constructor now has an optional 'timeout' parameter.
(Contributed by Donghee Na in bpo-39329(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39259

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39329


File: python.info,  Node: socket<3>,  Next: time<3>,  Prev: smtplib,  Up: Improved Modules<5>

1.5.6.30 socket
...............

The *note socket: cc. module now exports the *note CAN_RAW_JOIN_FILTERS:
93b. constant on Linux 4.1 and greater.  (Contributed by Stefan
Tatschner and Zackery Spytz in bpo-25780(1).)

The socket module now supports the *note CAN_J1939: 93c. protocol on
platforms that support it.  (Contributed by Karl Ding in bpo-40291(2).)

The socket module now has the *note socket.send_fds(): 93d. and *note
socket.recv_fds(): 93e. functions.  (Contributed by Joannah Nanjekye,
Shinya Okano and Victor Stinner in bpo-28724(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25780

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40291

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28724


File: python.info,  Node: time<3>,  Next: sys<6>,  Prev: socket<3>,  Up: Improved Modules<5>

1.5.6.31 time
.............

On AIX, *note thread_time(): 940. is now implemented with
‘thread_cputime()’ which has nanosecond resolution, rather than
‘clock_gettime(CLOCK_THREAD_CPUTIME_ID)’ which has a resolution of 10
milliseconds.  (Contributed by Batuhan Taskaya in bpo-40192(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40192


File: python.info,  Node: sys<6>,  Next: tracemalloc,  Prev: time<3>,  Up: Improved Modules<5>

1.5.6.32 sys
............

Added a new *note sys.platlibdir: 942. attribute: name of the
platform-specific library directory.  It is used to build the path of
standard library and the paths of installed extension modules.  It is
equal to ‘"lib"’ on most platforms.  On Fedora and SuSE, it is equal to
‘"lib64"’ on 64-bit platforms.  (Contributed by Jan Matějek, Matěj Cepl,
Charalampos Stratakis and Victor Stinner in bpo-1294959(1).)

Previously, *note sys.stderr: 943. was block-buffered when
non-interactive.  Now ‘stderr’ defaults to always being line-buffered.
(Contributed by Jendrik Seipp in bpo-13601(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1294959

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13601


File: python.info,  Node: tracemalloc,  Next: typing<6>,  Prev: sys<6>,  Up: Improved Modules<5>

1.5.6.33 tracemalloc
....................

Added *note tracemalloc.reset_peak(): 945. to set the peak size of
traced memory blocks to the current size, to measure the peak of
specific pieces of code.  (Contributed by Huon Wilson in bpo-40630(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40630


File: python.info,  Node: typing<6>,  Next: unicodedata<4>,  Prev: tracemalloc,  Up: Improved Modules<5>

1.5.6.34 typing
...............

PEP 593(1) introduced an *note typing.Annotated: 947. type to decorate
existing types with context-specific metadata and new ‘include_extras’
parameter to *note typing.get_type_hints(): 6b4. to access the metadata
at runtime.  (Contributed by Till Varoquaux and Konstantin Kashin.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0593/


File: python.info,  Node: unicodedata<4>,  Next: venv<3>,  Prev: typing<6>,  Up: Improved Modules<5>

1.5.6.35 unicodedata
....................

The Unicode database has been updated to version 13.0.0.
(bpo-39926(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39926


File: python.info,  Node: venv<3>,  Next: xml<3>,  Prev: unicodedata<4>,  Up: Improved Modules<5>

1.5.6.36 venv
.............

The activation scripts provided by *note venv: 111. now all specify
their prompt customization consistently by always using the value
specified by ‘__VENV_PROMPT__’.  Previously some scripts unconditionally
used ‘__VENV_PROMPT__’, others only if it happened to be set (which was
the default case), and one used ‘__VENV_NAME__’ instead.  (Contributed
by Brett Cannon in bpo-37663(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37663


File: python.info,  Node: xml<3>,  Prev: venv<3>,  Up: Improved Modules<5>

1.5.6.37 xml
............

White space characters within attributes are now preserved when
serializing *note xml.etree.ElementTree: 125. to XML file.  EOLNs are no
longer normalized to “n”.  This is the result of discussion about how to
interpret section 2.11 of XML spec.  (Contributed by Mefistotelis in
bpo-39011(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39011


File: python.info,  Node: Optimizations<5>,  Next: Deprecated<7>,  Prev: Improved Modules<5>,  Up: What’s New In Python 3 9

1.5.7 Optimizations
-------------------

   * Optimized the idiom for assignment a temporary variable in
     comprehensions.  Now ‘for y in [expr]’ in comprehensions is as fast
     as a simple assignment ‘y = expr’.  For example:

          sums = [s for s in [0] for x in data for s in [s + x]]

     Unlike the ‘:=’ operator this idiom does not leak a variable to the
     outer scope.

     (Contributed by Serhiy Storchaka in bpo-32856(1).)

   * Optimized signal handling in multithreaded applications.  If a
     thread different than the main thread gets a signal, the bytecode
     evaluation loop is no longer interrupted at each bytecode
     instruction to check for pending signals which cannot be handled.
     Only the main thread of the main interpreter can handle signals.

     Previously, the bytecode evaluation loop was interrupted at each
     instruction until the main thread handles signals.  (Contributed by
     Victor Stinner in bpo-40010(2).)

   * Optimized the *note subprocess: d6. module on FreeBSD using
     ‘closefrom()’.  (Contributed by Ed Maste, Conrad Meyer, Kyle Evans,
     Kubilay Kocak and Victor Stinner in bpo-38061(3).)

   * *note PyLong_FromDouble(): 94c. is now up to 1.87x faster for
     values that fit into long.  (Contributed by Sergey Fedoseev in
     bpo-37986(4).)

   * A number of Python builtins (*note range: 94d, *note tuple: 373,
     *note set: 5dc, *note frozenset: 5dd, *note list: 614, *note dict:
     256.) are now sped up by using PEP 590(5) vectorcall protocol.
     (Contributed by Donghee Na, Mark Shannon, Jeroen Demeyer and Petr
     Viktorin in bpo-37207(6).)

   * Optimized ‘set.difference_update()’ for the case when the other set
     is much larger than the base set.  (Suggested by Evgeny Kapun with
     code contributed by Michele Orrù in bpo-8425(7).)

   * Python’s small object allocator (‘obmalloc.c’) now allows (no more
     than) one empty arena to remain available for immediate reuse,
     without returning it to the OS. This prevents thrashing in simple
     loops where an arena could be created and destroyed anew on each
     iteration.  (Contributed by Tim Peters in bpo-37257(8).)

   * *note floor division: 94e. of float operation now has a better
     performance.  Also the message of *note ZeroDivisionError: 94f. for
     this operation is updated.  (Contributed by Donghee Na in
     bpo-39434(9).)

   * Decoding short ASCII strings with UTF-8 and ascii codecs is now
     about 15% faster.  (Contributed by Inada Naoki in bpo-37348(10).)

Here’s a summary of performance improvements from Python 3.4 through
Python 3.9:

     Python version                       3.4     3.5     3.6     3.7     3.8    3.9
     --------------                       ---     ---     ---     ---     ---    ---

     Variable and attribute read access:
         read_local                       7.1     7.1     5.4     5.1     3.9    3.9
         read_nonlocal                    7.1     8.1     5.8     5.4     4.4    4.5
         read_global                     15.5    19.0    14.3    13.6     7.6    7.8
         read_builtin                    21.1    21.6    18.5    19.0     7.5    7.8
         read_classvar_from_class        25.6    26.5    20.7    19.5    18.4   17.9
         read_classvar_from_instance     22.8    23.5    18.8    17.1    16.4   16.9
         read_instancevar                32.4    33.1    28.0    26.3    25.4   25.3
         read_instancevar_slots          27.8    31.3    20.8    20.8    20.2   20.5
         read_namedtuple                 73.8    57.5    45.0    46.8    18.4   18.7
         read_boundmethod                37.6    37.9    29.6    26.9    27.7   41.1

     Variable and attribute write access:
         write_local                      8.7     9.3     5.5     5.3     4.3    4.3
         write_nonlocal                  10.5    11.1     5.6     5.5     4.7    4.8
         write_global                    19.7    21.2    18.0    18.0    15.8   16.7
         write_classvar                  92.9    96.0   104.6   102.1    39.2   39.8
         write_instancevar               44.6    45.8    40.0    38.9    35.5   37.4
         write_instancevar_slots         35.6    36.1    27.3    26.6    25.7   25.8

     Data structure read access:
         read_list                       24.2    24.5    20.8    20.8    19.0   19.5
         read_deque                      24.7    25.5    20.2    20.6    19.8   20.2
         read_dict                       24.3    25.7    22.3    23.0    21.0   22.4
         read_strdict                    22.6    24.3    19.5    21.2    18.9   21.5

     Data structure write access:
         write_list                      27.1    28.5    22.5    21.6    20.0   20.0
         write_deque                     28.7    30.1    22.7    21.8    23.5   21.7
         write_dict                      31.4    33.3    29.3    29.2    24.7   25.4
         write_strdict                   28.4    29.9    27.5    25.2    23.1   24.5

     Stack (or queue) operations:
         list_append_pop                 93.4   112.7    75.4    74.2    50.8   50.6
         deque_append_pop                43.5    57.0    49.4    49.2    42.5   44.2
         deque_append_popleft            43.7    57.3    49.7    49.7    42.8   46.4

     Timing loop:
         loop_overhead                    0.5     0.6     0.4     0.3     0.3    0.3

These results were generated from the variable access benchmark script
at: ‘Tools/scripts/var_access_benchmark.py’.  The benchmark script
displays timings in nanoseconds.  The benchmarks were measured on an
Intel® Core™ i7-4960HQ processor(11) running the macOS 64-bit builds
found at python.org(12).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32856

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40010

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38061

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37986

   (5) https://peps.python.org/pep-0590/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (7) https://bugs.python.org/issue?@action=redirect&bpo=8425

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37257

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39434

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37348

   (11) 
https://ark.intel.com/content/www/us/en/ark/products/76088/intel-core-i7-4960hq-processor-6m-cache-up-to-3-80-ghz.html

   (12) https://www.python.org/downloads/macos/


File: python.info,  Node: Deprecated<7>,  Next: Removed<7>,  Prev: Optimizations<5>,  Up: What’s New In Python 3 9

1.5.8 Deprecated
----------------

   * The distutils ‘bdist_msi’ command is now deprecated, use
     ‘bdist_wheel’ (wheel packages) instead.  (Contributed by Hugo van
     Kemenade in bpo-39586(1).)

   * Currently *note math.factorial(): 951. accepts *note float: 2f7.
     instances with non-negative integer values (like ‘5.0’).  It raises
     a *note ValueError: 202. for non-integral and negative floats.  It
     is now deprecated.  In future Python versions it will raise a *note
     TypeError: 2c3. for all floats.  (Contributed by Serhiy Storchaka
     in bpo-37315(2).)

   * The ‘parser’ and ‘symbol’ modules are deprecated and will be
     removed in future versions of Python.  For the majority of use
     cases, users can leverage the Abstract Syntax Tree (AST) generation
     and compilation stage, using the *note ast: 8. module.

   * The Public C API functions ‘PyParser_SimpleParseStringFlags()’,
     ‘PyParser_SimpleParseStringFlagsFilename()’,
     ‘PyParser_SimpleParseFileFlags()’ and ‘PyNode_Compile()’ are
     deprecated and will be removed in Python 3.10 together with the old
     parser.

   * Using *note NotImplemented: 7d6. in a boolean context has been
     deprecated, as it is almost exclusively the result of incorrect
     rich comparator implementations.  It will be made a *note
     TypeError: 2c3. in a future version of Python.  (Contributed by
     Josh Rosenberg in bpo-35712(3).)

   * The *note random: b8. module currently accepts any hashable type as
     a possible seed value.  Unfortunately, some of those types are not
     guaranteed to have a deterministic hash value.  After Python 3.9,
     the module will restrict its seeds to *note None: 678, *note int:
     257, *note float: 2f7, *note str: 44f, *note bytes: 1c2, and *note
     bytearray: 2ea.

   * Opening the *note GzipFile: 41d. file for writing without
     specifying the 'mode' argument is deprecated.  In future Python
     versions it will always be opened for reading by default.  Specify
     the 'mode' argument for opening it for writing and silencing a
     warning.  (Contributed by Serhiy Storchaka in bpo-28286(4).)

   * Deprecated the ‘split()’ method of ‘_tkinter.TkappType’ in favour
     of the ‘splitlist()’ method which has more consistent and
     predictable behavior.  (Contributed by Serhiy Storchaka in
     bpo-38371(5).)

   * The explicit passing of coroutine objects to *note asyncio.wait():
     482. has been deprecated and will be removed in version 3.11.
     (Contributed by Yury Selivanov and Kyle Stanley in bpo-34790(6).)

   * binhex4 and hexbin4 standards are now deprecated.  The ‘binhex’
     module and the following *note binascii: 10. functions are now
     deprecated:

        * ‘b2a_hqx()’, ‘a2b_hqx()’

        * ‘rlecode_hqx()’, ‘rledecode_hqx()’

     (Contributed by Victor Stinner in bpo-39353(7).)

   * *note ast: 8. classes ‘slice’, ‘Index’ and ‘ExtSlice’ are
     considered deprecated and will be removed in future Python
     versions.  ‘value’ itself should be used instead of ‘Index(value)’.
     ‘Tuple(slices, Load())’ should be used instead of
     ‘ExtSlice(slices)’.  (Contributed by Serhiy Storchaka in
     bpo-34822(8).)

   * *note ast: 8. classes ‘Suite’, ‘Param’, ‘AugLoad’ and ‘AugStore’
     are considered deprecated and will be removed in future Python
     versions.  They were not generated by the parser and not accepted
     by the code generator in Python 3.  (Contributed by Batuhan Taskaya
     in bpo-39639(9) and bpo-39969(10) and Serhiy Storchaka in
     bpo-39988(11).)

   * The ‘PyEval_InitThreads()’ and ‘PyEval_ThreadsInitialized()’
     functions are now deprecated and will be removed in Python 3.11.
     Calling ‘PyEval_InitThreads()’ now does nothing.  The *note GIL:
     159. is initialized by *note Py_Initialize(): 8b4. since Python
     3.7.  (Contributed by Victor Stinner in bpo-39877(12).)

   * Passing ‘None’ as the first argument to the *note shlex.split():
     53f. function has been deprecated.  (Contributed by Zackery Spytz
     in bpo-33262(13).)

   * ‘smtpd.MailmanProxy()’ is now deprecated as it is unusable without
     an external module, ‘mailman’.  (Contributed by Samuel Colvin in
     bpo-35800(14).)

   * The ‘lib2to3’ module now emits a *note PendingDeprecationWarning:
     8d1.  Python 3.9 switched to a PEG parser (see PEP 617(15)), and
     Python 3.10 may include new language syntax that is not parsable by
     lib2to3’s LL(1) parser.  The ‘lib2to3’ module may be removed from
     the standard library in a future Python version.  Consider
     third-party alternatives such as LibCST(16) or parso(17).
     (Contributed by Carl Meyer in bpo-40360(18).)

   * The 'random' parameter of *note random.shuffle(): 74a. has been
     deprecated.  (Contributed by Raymond Hettinger in bpo-40465(19))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39586

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37315

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35712

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28286

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38371

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34790

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39353

   (8) https://bugs.python.org/issue?@action=redirect&bpo=34822

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39639

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39969

   (11) https://bugs.python.org/issue?@action=redirect&bpo=39988

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39877

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33262

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35800

   (15) https://peps.python.org/pep-0617/

   (16) https://libcst.readthedocs.io/

   (17) https://parso.readthedocs.io/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=40360

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40465


File: python.info,  Node: Removed<7>,  Next: Porting to Python 3 9,  Prev: Deprecated<7>,  Up: What’s New In Python 3 9

1.5.9 Removed
-------------

   * The erroneous version at ‘unittest.mock.__version__’ has been
     removed.

   * ‘nntplib.NNTP’: ‘xpath()’ and ‘xgtitle()’ methods have been
     removed.  These methods are deprecated since Python 3.3.
     Generally, these extensions are not supported or not enabled by
     NNTP server administrators.  For ‘xgtitle()’, please use
     ‘nntplib.NNTP.descriptions()’ or ‘nntplib.NNTP.description()’
     instead.  (Contributed by Donghee Na in bpo-39366(1).)

   * *note array.array: 1a0.: ‘tostring()’ and ‘fromstring()’ methods
     have been removed.  They were aliases to ‘tobytes()’ and
     ‘frombytes()’, deprecated since Python 3.2.  (Contributed by Victor
     Stinner in bpo-38916(2).)

   * The undocumented ‘sys.callstats()’ function has been removed.
     Since Python 3.7, it was deprecated and always returned *note None:
     678.  It required a special build option ‘CALL_PROFILE’ which was
     already removed in Python 3.7.  (Contributed by Victor Stinner in
     bpo-37414(3).)

   * The ‘sys.getcheckinterval()’ and ‘sys.setcheckinterval()’ functions
     have been removed.  They were deprecated since Python 3.2.  Use
     *note sys.getswitchinterval(): 953. and *note
     sys.setswitchinterval(): 954. instead.  (Contributed by Victor
     Stinner in bpo-37392(4).)

   * The C function ‘PyImport_Cleanup()’ has been removed.  It was
     documented as: “Empty the module table.  For internal use only.”
     (Contributed by Victor Stinner in bpo-36710(5).)

   * ‘_dummy_thread’ and ‘dummy_threading’ modules have been removed.
     These modules were deprecated since Python 3.7 which requires
     threading support.  (Contributed by Victor Stinner in
     bpo-37312(6).)

   * ‘aifc.openfp()’ alias to ‘aifc.open()’, ‘sunau.openfp()’ alias to
     ‘sunau.open()’, and ‘wave.openfp()’ alias to *note wave.open():
     955. have been removed.  They were deprecated since Python 3.7.
     (Contributed by Victor Stinner in bpo-37320(7).)

   * The ‘isAlive()’ method of *note threading.Thread: 956. has been
     removed.  It was deprecated since Python 3.8.  Use *note
     is_alive(): 957. instead.  (Contributed by Donghee Na in
     bpo-37804(8).)

   * Methods ‘getchildren()’ and ‘getiterator()’ of classes *note
     ElementTree: 958. and *note Element: 310. in the *note ElementTree:
     125. module have been removed.  They were deprecated in Python 3.2.
     Use ‘iter(x)’ or ‘list(x)’ instead of ‘x.getchildren()’ and
     ‘x.iter()’ or ‘list(x.iter())’ instead of ‘x.getiterator()’.
     (Contributed by Serhiy Storchaka in bpo-36543(9).)

   * The old *note plistlib: ab. API has been removed, it was deprecated
     since Python 3.4.  Use the *note load(): 959, *note loads(): 95a,
     *note dump(): 95b, and *note dumps(): 95c. functions.
     Additionally, the 'use_builtin_types' parameter was removed,
     standard *note bytes: 1c2. objects are always used instead.
     (Contributed by Jon Janzen in bpo-36409(10).)

   * The C function ‘PyGen_NeedsFinalizing’ has been removed.  It was
     not documented, tested, or used anywhere within CPython after the
     implementation of PEP 442(11).  Patch by Joannah Nanjekye.
     (Contributed by Joannah Nanjekye in bpo-15088(12))

   * ‘base64.encodestring()’ and ‘base64.decodestring()’, aliases
     deprecated since Python 3.1, have been removed: use *note
     base64.encodebytes(): 95d. and *note base64.decodebytes(): 95e.
     instead.  (Contributed by Victor Stinner in bpo-39351(13).)

   * ‘fractions.gcd()’ function has been removed, it was deprecated
     since Python 3.5 (bpo-22486(14)): use *note math.gcd(): 919.
     instead.  (Contributed by Victor Stinner in bpo-39350(15).)

   * The 'buffering' parameter of *note bz2.BZ2File: 86d. has been
     removed.  Since Python 3.0, it was ignored and using it emitted a
     *note DeprecationWarning: 1a5.  Pass an open file object to control
     how the file is opened.  (Contributed by Victor Stinner in
     bpo-39357(16).)

   * The 'encoding' parameter of *note json.loads(): 95f. has been
     removed.  As of Python 3.1, it was deprecated and ignored; using it
     has emitted a *note DeprecationWarning: 1a5. since Python 3.8.
     (Contributed by Inada Naoki in bpo-39377(17))

   * ‘with (await asyncio.lock):’ and ‘with (yield from asyncio.lock):’
     statements are not longer supported, use ‘async with lock’ instead.
     The same is correct for ‘asyncio.Condition’ and
     ‘asyncio.Semaphore’.  (Contributed by Andrew Svetlov in
     bpo-34793(18).)

   * The ‘sys.getcounts()’ function, the ‘-X showalloccount’ command
     line option and the ‘show_alloc_count’ field of the C structure
     *note PyConfig: 3a9. have been removed.  They required a special
     Python build by defining ‘COUNT_ALLOCS’ macro.  (Contributed by
     Victor Stinner in bpo-39489(19).)

   * The ‘_field_types’ attribute of the *note typing.NamedTuple: 2b0.
     class has been removed.  It was deprecated since Python 3.8.  Use
     the ‘__annotations__’ attribute instead.  (Contributed by Serhiy
     Storchaka in bpo-40182(20).)

   * The ‘symtable.SymbolTable.has_exec()’ method has been removed.  It
     was deprecated since 2006, and only returning ‘False’ when it’s
     called.  (Contributed by Batuhan Taskaya in bpo-40208(21))

   * The ‘asyncio.Task.current_task()’ and ‘asyncio.Task.all_tasks()’
     have been removed.  They were deprecated since Python 3.7 and you
     can use *note asyncio.current_task(): 480. and *note
     asyncio.all_tasks(): 960. instead.  (Contributed by Rémi Lapeyre in
     bpo-40967(22))

   * The ‘unescape()’ method in the *note html.parser.HTMLParser: 87e.
     class has been removed (it was deprecated since Python 3.4).  *note
     html.unescape(): 961. should be used for converting character
     references to the corresponding unicode characters.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39366

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38916

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37414

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37392

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36710

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37312

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37320

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37804

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36543

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36409

   (11) https://peps.python.org/pep-0442/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=15088

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39351

   (14) https://bugs.python.org/issue?@action=redirect&bpo=22486

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39350

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39357

   (17) https://bugs.python.org/issue?@action=redirect&bpo=39377

   (18) https://bugs.python.org/issue?@action=redirect&bpo=34793

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39489

   (20) https://bugs.python.org/issue?@action=redirect&bpo=40182

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40208

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40967


File: python.info,  Node: Porting to Python 3 9,  Next: Build Changes<5>,  Prev: Removed<7>,  Up: What’s New In Python 3 9

1.5.10 Porting to Python 3.9
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in the Python API: Changes in the Python API<4>.
* Changes in the C API: Changes in the C API<3>.
* CPython bytecode changes: CPython bytecode changes<4>.


File: python.info,  Node: Changes in the Python API<4>,  Next: Changes in the C API<3>,  Up: Porting to Python 3 9

1.5.10.1 Changes in the Python API
..................................

   * *note __import__(): 8dd. and *note importlib.util.resolve_name():
     913. now raise *note ImportError: 41c. where it previously raised
     *note ValueError: 202.  Callers catching the specific exception
     type and supporting both Python 3.9 and earlier versions will need
     to catch both using ‘except (ImportError, ValueError):’.

   * The *note venv: 111. activation scripts no longer special-case when
     ‘__VENV_PROMPT__’ is set to ‘""’.

   * The *note select.epoll.unregister(): 964. method no longer ignores
     the *note EBADF: 965. error.  (Contributed by Victor Stinner in
     bpo-39239(1).)

   * The 'compresslevel' parameter of *note bz2.BZ2File: 86d. became
     keyword-only, since the 'buffering' parameter has been removed.
     (Contributed by Victor Stinner in bpo-39357(2).)

   * Simplified AST for subscription.  Simple indices will be
     represented by their value, extended slices will be represented as
     tuples.  ‘Index(value)’ will return a ‘value’ itself,
     ‘ExtSlice(slices)’ will return ‘Tuple(slices, Load())’.
     (Contributed by Serhiy Storchaka in bpo-34822(3).)

   * The *note importlib: 77. module now ignores the *note PYTHONCASEOK:
     966. environment variable when the *note -E: 967. or *note -I: 968.
     command line options are being used.

   * The 'encoding' parameter has been added to the classes *note
     ftplib.FTP: 903. and *note ftplib.FTP_TLS: 904. as a keyword-only
     parameter, and the default encoding is changed from Latin-1 to
     UTF-8 to follow RFC 2640(4).

   * *note asyncio.loop.shutdown_default_executor(): 8f0. has been added
     to *note AbstractEventLoop: 969, meaning alternative event loops
     that inherit from it should have this method defined.  (Contributed
     by Kyle Stanley in bpo-34037(5).)

   * The constant values of future flags in the *note __future__: 0.
     module is updated in order to prevent collision with compiler
     flags.  Previously ‘PyCF_ALLOW_TOP_LEVEL_AWAIT’ was clashing with
     ‘CO_FUTURE_DIVISION’.  (Contributed by Batuhan Taskaya in
     bpo-39562(6))

   * ‘array('u')’ now uses ‘wchar_t’ as C type instead of ‘Py_UNICODE’.
     This change doesn’t affect to its behavior because ‘Py_UNICODE’ is
     alias of ‘wchar_t’ since Python 3.3.  (Contributed by Inada Naoki
     in bpo-34538(7).)

   * The *note logging.getLogger(): 96a. API now returns the root logger
     when passed the name ‘'root'’, whereas previously it returned a
     non-root logger named ‘'root'’.  This could affect cases where user
     code explicitly wants a non-root logger named ‘'root'’, or
     instantiates a logger using ‘logging.getLogger(__name__)’ in some
     top-level module called ‘'root.py'’.  (Contributed by Vinay Sajip
     in bpo-37742(8).)

   * Division handling of *note PurePath: 4a9. now returns *note
     NotImplemented: 7d6. instead of raising a *note TypeError: 2c3.
     when passed something other than an instance of ‘str’ or
     ‘PurePath’.  This allows creating compatible classes that don’t
     inherit from those mentioned types.  (Contributed by Roger Aiudi in
     bpo-34775(9)).

   * Starting with Python 3.9.5 the *note ipaddress: 80. module no
     longer accepts any leading zeros in IPv4 address strings.  Leading
     zeros are ambiguous and interpreted as octal notation by some
     libraries.  For example the legacy function *note
     socket.inet_aton(): 96b. treats leading zeros as octal notatation.
     glibc implementation of modern *note inet_pton(): 96c. does not
     accept any leading zeros.  (Contributed by Christian Heimes in
     bpo-36384(10)).

   * *note codecs.lookup(): 96d. now normalizes the encoding name the
     same way as *note encodings.normalize_encoding(): 801, except that
     ‘codecs.lookup()’ also converts the name to lower case.  For
     example, ‘"latex+latin1"’ encoding name is now normalized to
     ‘"latex_latin1"’.  (Contributed by Jordon Xu in bpo-37751(11).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39239

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39357

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34822

   (4) https://datatracker.ietf.org/doc/html/rfc2640.html

   (5) https://bugs.python.org/issue?@action=redirect&bpo=34037

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39562

   (7) https://bugs.python.org/issue?@action=redirect&bpo=34538

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37742

   (9) https://bugs.python.org/issue?@action=redirect&bpo=34775

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36384

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37751


File: python.info,  Node: Changes in the C API<3>,  Next: CPython bytecode changes<4>,  Prev: Changes in the Python API<4>,  Up: Porting to Python 3 9

1.5.10.2 Changes in the C API
.............................

   * Instances of *note heap-allocated types: 96f. (such as those
     created with *note PyType_FromSpec(): 580. and similar APIs) hold a
     reference to their type object since Python 3.8.  As indicated in
     the “Changes in the C API” of Python 3.8, for the vast majority of
     cases, there should be no side effect but for types that have a
     custom *note tp_traverse: 781. function, ensure that all custom
     ‘tp_traverse’ functions of heap-allocated types visit the object’s
     type.

          Example:

               int
               foo_traverse(foo_struct *self, visitproc visit, void *arg) {
               // Rest of the traverse function
               #if PY_VERSION_HEX >= 0x03090000
                   // This was not needed before Python 3.9 (Python issue 35810 and 40217)
                   Py_VISIT(Py_TYPE(self));
               #endif
               }

     If your traverse function delegates to ‘tp_traverse’ of its base
     class (or another type), ensure that ‘Py_TYPE(self)’ is visited
     only once.  Note that only *note heap type: 96f. are expected to
     visit the type in ‘tp_traverse’.

          For example, if your ‘tp_traverse’ function includes:

               base->tp_traverse(self, visit, arg)

          then add:

               #if PY_VERSION_HEX >= 0x03090000
                   // This was not needed before Python 3.9 (bpo-35810 and bpo-40217)
                   if (base->tp_flags & Py_TPFLAGS_HEAPTYPE) {
                       // a heap type's tp_traverse already visited Py_TYPE(self)
                   } else {
                       Py_VISIT(Py_TYPE(self));
                   }
               #else

     (See bpo-35810(1) and bpo-40217(2) for more information.)

   * The functions ‘PyEval_CallObject’, ‘PyEval_CallFunction’,
     ‘PyEval_CallMethod’ and ‘PyEval_CallObjectWithKeywords’ are
     deprecated.  Use *note PyObject_Call(): 39f. and its variants
     instead.  (See more details in bpo-29548(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35810

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40217

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29548


File: python.info,  Node: CPython bytecode changes<4>,  Prev: Changes in the C API<3>,  Up: Porting to Python 3 9

1.5.10.3 CPython bytecode changes
.................................

   * The *note LOAD_ASSERTION_ERROR: 971. opcode was added for handling
     the *note assert: 972. statement.  Previously, the assert statement
     would not work correctly if the *note AssertionError: 6ac.
     exception was being shadowed.  (Contributed by Zackery Spytz in
     bpo-34880(1).)

   * The *note COMPARE_OP: 973. opcode was split into four distinct
     instructions:

        * ‘COMPARE_OP’ for rich comparisons

        * ‘IS_OP’ for ‘is’ and ‘is not’ tests

        * ‘CONTAINS_OP’ for ‘in’ and ‘not in’ tests

        * ‘JUMP_IF_NOT_EXC_MATCH’ for checking exceptions in
          ‘try-except’ statements.

     (Contributed by Mark Shannon in bpo-39156(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34880

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39156


File: python.info,  Node: Build Changes<5>,  Next: C API Changes<5>,  Prev: Porting to Python 3 9,  Up: What’s New In Python 3 9

1.5.11 Build Changes
--------------------

   * Added ‘--with-platlibdir’ option to the ‘configure’ script: name of
     the platform-specific library directory, stored in the new *note
     sys.platlibdir: 942. attribute.  See ‘sys.platlibdir’ attribute for
     more information.  (Contributed by Jan Matějek, Matěj Cepl,
     Charalampos Stratakis and Victor Stinner in bpo-1294959(1).)

   * The ‘COUNT_ALLOCS’ special build macro has been removed.
     (Contributed by Victor Stinner in bpo-39489(2).)

   * On non-Windows platforms, the ‘setenv()’ and ‘unsetenv()’ functions
     are now required to build Python.  (Contributed by Victor Stinner
     in bpo-39395(3).)

   * On non-Windows platforms, creating ‘bdist_wininst’ installers is
     now officially unsupported.  (See bpo-10945(4) for more details.)

   * When building Python on macOS from source, ‘_tkinter’ now links
     with non-system Tcl and Tk frameworks if they are installed in
     ‘/Library/Frameworks’, as had been the case on older releases of
     macOS. If a macOS SDK is explicitly configured, by using *note
     -enable-universalsdk: 975. or ‘-isysroot’, only the SDK itself is
     searched.  The default behavior can still be overridden with
     ‘--with-tcltk-includes’ and ‘--with-tcltk-libs’.  (Contributed by
     Ned Deily in bpo-34956(5).)

   * Python can now be built for Windows 10 ARM64.  (Contributed by
     Steve Dower in bpo-33125(6).)

   * Some individual tests are now skipped when ‘--pgo’ is used.  The
     tests in question increased the PGO task time significantly and
     likely didn’t help improve optimization of the final executable.
     This speeds up the task by a factor of about 15x.  Running the full
     unit test suite is slow.  This change may result in a slightly less
     optimized build since not as many code branches will be executed.
     If you are willing to wait for the much slower build, the old
     behavior can be restored using ‘./configure [..] PROFILE_TASK="-m
     test --pgo-extended"’.  We make no guarantees as to which PGO task
     set produces a faster build.  Users who care should run their own
     relevant benchmarks as results can depend on the environment,
     workload, and compiler tool chain.  (See bpo-36044(7) and
     bpo-37707(8) for more details.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1294959

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39489

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39395

   (4) https://bugs.python.org/issue?@action=redirect&bpo=10945

   (5) https://bugs.python.org/issue?@action=redirect&bpo=34956

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33125

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36044

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37707


File: python.info,  Node: C API Changes<5>,  Next: Notable changes in Python 3 9 1,  Prev: Build Changes<5>,  Up: What’s New In Python 3 9

1.5.12 C API Changes
--------------------

* Menu:

* New Features: New Features<10>.
* Porting to Python 3.9: Porting to Python 3 9<2>.
* Removed: Removed<8>.


File: python.info,  Node: New Features<10>,  Next: Porting to Python 3 9<2>,  Up: C API Changes<5>

1.5.12.1 New Features
.....................

   * PEP 573(1): Added *note PyType_FromModuleAndSpec(): 554. to
     associate a module with a class; *note PyType_GetModule(): 978. and
     *note PyType_GetModuleState(): 979. to retrieve the module and its
     state; and *note PyCMethod: 767. and *note METH_METHOD: 97a. to
     allow a method to access the class it was defined in.  (Contributed
     by Marcel Plch and Petr Viktorin in bpo-38787(2).)

   * Added *note PyFrame_GetCode(): 78d. function: get a frame code.
     Added *note PyFrame_GetBack(): 789. function: get the frame next
     outer frame.  (Contributed by Victor Stinner in bpo-40421(3).)

   * Added *note PyFrame_GetLineNumber(): 78e. to the limited C API.
     (Contributed by Victor Stinner in bpo-40421(4).)

   * Added *note PyThreadState_GetInterpreter(): 97b. and *note
     PyInterpreterState_Get(): 3b0. functions to get the interpreter.
     Added *note PyThreadState_GetFrame(): 791. function to get the
     current frame of a Python thread state.  Added *note
     PyThreadState_GetID(): 97c. function: get the unique identifier of
     a Python thread state.  (Contributed by Victor Stinner in
     bpo-39947(5).)

   * Added a new public *note PyObject_CallNoArgs(): 39e. function to
     the C API, which calls a callable Python object without any
     arguments.  It is the most efficient way to call a callable Python
     object without any argument.  (Contributed by Victor Stinner in
     bpo-37194(6).)

   * Changes in the limited C API (if ‘Py_LIMITED_API’ macro is
     defined):

        * Provide *note Py_EnterRecursiveCall(): 97d. and *note
          Py_LeaveRecursiveCall(): 97e. as regular functions for the
          limited API. Previously, there were defined as macros, but
          these macros didn’t compile with the limited C API which
          cannot access ‘PyThreadState.recursion_depth’ field (the
          structure is opaque in the limited C API).

        * ‘PyObject_INIT()’ and ‘PyObject_INIT_VAR()’ become regular
          “opaque” function to hide implementation details.

     (Contributed by Victor Stinner in bpo-38644(7) and bpo-39542(8).)

   * The *note PyModule_AddType(): 97f. function is added to help adding
     a type to a module.  (Contributed by Donghee Na in bpo-40024(9).)

   * Added the functions *note PyObject_GC_IsTracked(): 980. and *note
     PyObject_GC_IsFinalized(): 981. to the public API to allow to query
     if Python objects are being currently tracked or have been already
     finalized by the garbage collector respectively.  (Contributed by
     Pablo Galindo Salgado in bpo-40241(10).)

   * Added ‘_PyObject_FunctionStr()’ to get a user-friendly string
     representation of a function-like object.  (Patch by Jeroen Demeyer
     in bpo-37645(11).)

   * Added *note PyObject_CallOneArg(): 982. for calling an object with
     one positional argument (Patch by Jeroen Demeyer in bpo-37483(12).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0573/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38787

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37194

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38644

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39542

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40024

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40241

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37645

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37483


File: python.info,  Node: Porting to Python 3 9<2>,  Next: Removed<8>,  Prev: New Features<10>,  Up: C API Changes<5>

1.5.12.2 Porting to Python 3.9
..............................

   * ‘PyInterpreterState.eval_frame’ ( PEP 523(1)) now requires a new
     mandatory 'tstate' parameter (‘PyThreadState*’).  (Contributed by
     Victor Stinner in bpo-38500(2).)

   * Extension modules: *note m_traverse: 984, *note m_clear: 985. and
     *note m_free: 986. functions of *note PyModuleDef: 987. are no
     longer called if the module state was requested but is not
     allocated yet.  This is the case immediately after the module is
     created and before the module is executed (*note Py_mod_exec: 988.
     function).  More precisely, these functions are not called if *note
     m_size: 989. is greater than 0 and the module state (as returned by
     *note PyModule_GetState(): 98a.) is ‘NULL’.

     Extension modules without module state (‘m_size <= 0’) are not
     affected.

   * If *note Py_AddPendingCall(): 98b. is called in a subinterpreter,
     the function is now scheduled to be called from the subinterpreter,
     rather than being called from the main interpreter.  Each
     subinterpreter now has its own list of scheduled calls.
     (Contributed by Victor Stinner in bpo-39984(3).)

   * The Windows registry is no longer used to initialize *note
     sys.path: 3b7. when the ‘-E’ option is used (if *note
     PyConfig.use_environment: 3dc. is set to ‘0’).  This is significant
     when embedding Python on Windows.  (Contributed by Zackery Spytz in
     bpo-8901(4).)

   * The global variable *note PyStructSequence_UnnamedField: 98c. is
     now a constant and refers to a constant string.  (Contributed by
     Serhiy Storchaka in bpo-38650(5).)

   * The ‘PyGC_Head’ structure is now opaque.  It is only defined in the
     internal C API (‘pycore_gc.h’).  (Contributed by Victor Stinner in
     bpo-40241(6).)

   * The ‘Py_UNICODE_COPY’, ‘Py_UNICODE_FILL’, ‘PyUnicode_WSTR_LENGTH’,
     ‘PyUnicode_FromUnicode()’, ‘PyUnicode_AsUnicode()’,
     ‘_PyUnicode_AsUnicode’, and ‘PyUnicode_AsUnicodeAndSize()’ are
     marked as deprecated in C. They have been deprecated by PEP 393(7)
     since Python 3.3.  (Contributed by Inada Naoki in bpo-36346(8).)

   * The *note Py_FatalError(): 98d. function is replaced with a macro
     which logs automatically the name of the current function, unless
     the ‘Py_LIMITED_API’ macro is defined.  (Contributed by Victor
     Stinner in bpo-39882(9).)

   * The vectorcall protocol now requires that the caller passes only
     strings as keyword names.  (See bpo-37540(10) for more
     information.)

   * Implementation details of a number of macros and functions are now
     hidden:

        * *note PyObject_IS_GC(): 98e. macro was converted to a
          function.

        * The ‘PyObject_NEW()’ macro becomes an alias to the *note
          PyObject_New: 98f. macro, and the ‘PyObject_NEW_VAR()’ macro
          becomes an alias to the *note PyObject_NewVar: 990. macro.
          They no longer access directly the *note
          PyTypeObject.tp_basicsize: 991. member.

        * ‘PyObject_GET_WEAKREFS_LISTPTR()’ macro was converted to a
          function: the macro accessed directly the *note
          PyTypeObject.tp_weaklistoffset: 992. member.

        * *note PyObject_CheckBuffer(): 39b. macro was converted to a
          function: the macro accessed directly the *note
          PyTypeObject.tp_as_buffer: 993. member.

        * *note PyIndex_Check(): 994. is now always declared as an
          opaque function to hide implementation details: removed the
          ‘PyIndex_Check()’ macro.  The macro accessed directly the
          *note PyTypeObject.tp_as_number: 995. member.

     (See bpo-40170(11) for more details.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0523/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38500

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39984

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8901

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38650

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40241

   (7) https://peps.python.org/pep-0393/

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39882

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37540

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40170


File: python.info,  Node: Removed<8>,  Prev: Porting to Python 3 9<2>,  Up: C API Changes<5>

1.5.12.3 Removed
................

   * Excluded ‘PyFPE_START_PROTECT()’ and ‘PyFPE_END_PROTECT()’ macros
     of ‘pyfpe.h’ from the limited C API. (Contributed by Victor Stinner
     in bpo-38835(1).)

   * The ‘tp_print’ slot of *note PyTypeObject: 997. has been removed.
     It was used for printing objects to files in Python 2.7 and before.
     Since Python 3.0, it has been ignored and unused.  (Contributed by
     Jeroen Demeyer in bpo-36974(2).)

   * Changes in the limited C API (if ‘Py_LIMITED_API’ macro is
     defined):

        * Excluded the following functions from the limited C API:

             * ‘PyThreadState_DeleteCurrent()’ (Contributed by Joannah
               Nanjekye in bpo-37878(3).)

             * ‘_Py_CheckRecursionLimit’

             * ‘_Py_NewReference()’

             * ‘_Py_ForgetReference()’

             * ‘_PyTraceMalloc_NewReference()’

             * ‘_Py_GetRefTotal()’

             * The trashcan mechanism which never worked in the limited
               C API.

             * ‘PyTrash_UNWIND_LEVEL’

             * ‘Py_TRASHCAN_BEGIN_CONDITION’

             * ‘Py_TRASHCAN_BEGIN’

             * ‘Py_TRASHCAN_END’

             * ‘Py_TRASHCAN_SAFE_BEGIN’

             * ‘Py_TRASHCAN_SAFE_END’

        * Moved following functions and definitions to the internal C
          API:

             * ‘_PyDebug_PrintTotalRefs()’

             * ‘_Py_PrintReferences()’

             * ‘_Py_PrintReferenceAddresses()’

             * ‘_Py_tracemalloc_config’

             * ‘_Py_AddToAllObjects()’ (specific to ‘Py_TRACE_REFS’
               build)

     (Contributed by Victor Stinner in bpo-38644(4) and bpo-39542(5).)

   * Removed ‘_PyRuntime.getframe’ hook and removed
     ‘_PyThreadState_GetFrame’ macro which was an alias to
     ‘_PyRuntime.getframe’.  They were only exposed by the internal C
     API. Removed also ‘PyThreadFrameGetter’ type.  (Contributed by
     Victor Stinner in bpo-39946(6).)

   * Removed the following functions from the C API. Call *note
     PyGC_Collect(): 998. explicitly to clear all free lists.
     (Contributed by Inada Naoki and Victor Stinner in bpo-37340(7),
     bpo-38896(8) and bpo-40428(9).)

        * ‘PyAsyncGen_ClearFreeLists()’

        * ‘PyContext_ClearFreeList()’

        * ‘PyDict_ClearFreeList()’

        * ‘PyFloat_ClearFreeList()’

        * ‘PyFrame_ClearFreeList()’

        * ‘PyList_ClearFreeList()’

        * ‘PyMethod_ClearFreeList()’ and ‘PyCFunction_ClearFreeList()’:
          the free lists of bound method objects have been removed.

        * ‘PySet_ClearFreeList()’: the set free list has been removed in
          Python 3.4.

        * ‘PyTuple_ClearFreeList()’

        * ‘PyUnicode_ClearFreeList()’: the Unicode free list has been
          removed in Python 3.3.

   * Removed ‘_PyUnicode_ClearStaticStrings()’ function.  (Contributed
     by Victor Stinner in bpo-39465(10).)

   * Removed ‘Py_UNICODE_MATCH’.  It has been deprecated by PEP 393(11),
     and broken since Python 3.3.  The *note PyUnicode_Tailmatch(): 8c0.
     function can be used instead.  (Contributed by Inada Naoki in
     bpo-36346(12).)

   * Cleaned header files of interfaces defined but with no
     implementation.  The public API symbols being removed are:
     ‘_PyBytes_InsertThousandsGroupingLocale’,
     ‘_PyBytes_InsertThousandsGrouping’, ‘_Py_InitializeFromArgs’,
     ‘_Py_InitializeFromWideArgs’, ‘_PyFloat_Repr’, ‘_PyFloat_Digits’,
     ‘_PyFloat_DigitsInit’, ‘PyFrame_ExtendStack’,
     ‘_PyAIterWrapper_Type’, ‘PyNullImporter_Type’, ‘PyCmpWrapper_Type’,
     ‘PySortWrapper_Type’, ‘PyNoArgsFunction’.  (Contributed by Pablo
     Galindo Salgado in bpo-39372(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38835

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36974

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37878

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38644

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39542

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39946

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37340

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38896

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40428

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39465

   (11) https://peps.python.org/pep-0393/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39372


File: python.info,  Node: Notable changes in Python 3 9 1,  Next: Notable changes in Python 3 9 2,  Prev: C API Changes<5>,  Up: What’s New In Python 3 9

1.5.13 Notable changes in Python 3.9.1
--------------------------------------

* Menu:

* typing: typing<7>.
* macOS 11.0 (Big Sur) and Apple Silicon Mac support: macOS 11 0 Big Sur and Apple Silicon Mac support.


File: python.info,  Node: typing<7>,  Next: macOS 11 0 Big Sur and Apple Silicon Mac support,  Up: Notable changes in Python 3 9 1

1.5.13.1 typing
...............

The behavior of *note typing.Literal: 85b. was changed to conform with
PEP 586(1) and to match the behavior of static type checkers specified
in the PEP.

  1. ‘Literal’ now de-duplicates parameters.

  2. Equality comparisons between ‘Literal’ objects are now order
     independent.

  3. ‘Literal’ comparisons now respect types.  For example, ‘Literal[0]
     == Literal[False]’ previously evaluated to ‘True’.  It is now
     ‘False’.  To support this change, the internally used type cache
     now supports differentiating types.

  4. ‘Literal’ objects will now raise a *note TypeError: 2c3. exception
     during equality comparisons if any of their parameters are not
     *note hashable: 613.  Note that declaring ‘Literal’ with mutable
     parameters will not throw an error:

          >>> from typing import Literal
          >>> Literal[{0}]
          >>> Literal[{0}] == Literal[{False}]
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          TypeError: unhashable type: 'set'

(Contributed by Yurii Karabas in bpo-42345(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0586/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42345


File: python.info,  Node: macOS 11 0 Big Sur and Apple Silicon Mac support,  Prev: typing<7>,  Up: Notable changes in Python 3 9 1

1.5.13.2 macOS 11.0 (Big Sur) and Apple Silicon Mac support
...........................................................

As of 3.9.1, Python now fully supports building and running on macOS
11.0 (Big Sur) and on Apple Silicon Macs (based on the ‘ARM64’
architecture).  A new universal build variant, ‘universal2’, is now
available to natively support both ‘ARM64’ and ‘Intel 64’ in one set of
executables.  Binaries can also now be built on current versions of
macOS to be deployed on a range of older macOS versions (tested to 10.9)
while making some newer OS functions and options conditionally available
based on the operating system version in use at runtime (“weaklinking”).

(Contributed by Ronald Oussoren and Lawrence D’Anna in bpo-41100(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41100


File: python.info,  Node: Notable changes in Python 3 9 2,  Next: Notable changes in Python 3 9 3,  Prev: Notable changes in Python 3 9 1,  Up: What’s New In Python 3 9

1.5.14 Notable changes in Python 3.9.2
--------------------------------------

* Menu:

* collections.abc: collections abc<2>.
* urllib.parse: urllib parse<2>.


File: python.info,  Node: collections abc<2>,  Next: urllib parse<2>,  Up: Notable changes in Python 3 9 2

1.5.14.1 collections.abc
........................

*note collections.abc.Callable: 7ef. generic now flattens type
parameters, similar to what *note typing.Callable: 7c9. currently does.
This means that ‘collections.abc.Callable[[int, str], str]’ will have
‘__args__’ of ‘(int, str, str)’; previously this was ‘([int, str],
str)’.  To allow this change, *note types.GenericAlias: 7f0. can now be
subclassed, and a subclass will be returned when subscripting the
‘collections.abc.Callable’ type.  Code which accesses the arguments via
*note typing.get_args(): 2ed. or ‘__args__’ need to account for this
change.  A *note DeprecationWarning: 1a5. may be emitted for invalid
forms of parameterizing ‘collections.abc.Callable’ which may have passed
silently in Python 3.9.1.  This ‘DeprecationWarning’ will become a *note
TypeError: 2c3. in Python 3.10.  (Contributed by Ken Jin in
bpo-42195(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42195


File: python.info,  Node: urllib parse<2>,  Prev: collections abc<2>,  Up: Notable changes in Python 3 9 2

1.5.14.2 urllib.parse
.....................

Earlier Python versions allowed using both ‘;’ and ‘&’ as query
parameter separators in *note urllib.parse.parse_qs(): 27a. and *note
urllib.parse.parse_qsl(): 279.  Due to security concerns, and to conform
with newer W3C recommendations, this has been changed to allow only a
single separator key, with ‘&’ as the default.  This change also affects
‘cgi.parse()’ and ‘cgi.parse_multipart()’ as they use the affected
functions internally.  For more details, please see their respective
documentation.  (Contributed by Adam Goldschmidt, Senthil Kumaran and
Ken Jin in bpo-42967(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967


File: python.info,  Node: Notable changes in Python 3 9 3,  Next: Notable changes in Python 3 9 5,  Prev: Notable changes in Python 3 9 2,  Up: What’s New In Python 3 9

1.5.15 Notable changes in Python 3.9.3
--------------------------------------

A security fix alters the *note ftplib.FTP: 903. behavior to not trust
the IPv4 address sent from the remote server when setting up a passive
data channel.  We reuse the ftp server IP address instead.  For unusual
code requiring the old behavior, set a ‘trust_server_pasv_ipv4_address’
attribute on your FTP instance to ‘True’.  (See gh-87451(1))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87451


File: python.info,  Node: Notable changes in Python 3 9 5,  Next: Notable security feature in 3 9 14,  Prev: Notable changes in Python 3 9 3,  Up: What’s New In Python 3 9

1.5.16 Notable changes in Python 3.9.5
--------------------------------------

* Menu:

* urllib.parse: urllib parse<3>.


File: python.info,  Node: urllib parse<3>,  Up: Notable changes in Python 3 9 5

1.5.16.1 urllib.parse
.....................

The presence of newline or tab characters in parts of a URL allows for
some forms of attacks.  Following the WHATWG specification that updates
RFC 3986(1), ASCII newline ‘\n’, ‘\r’ and tab ‘\t’ characters are
stripped from the URL by the parser in *note urllib.parse: 10a.
preventing such attacks.  The removal characters are controlled by a new
module level variable ‘urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE’.  (See
gh-88048(2))

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3986.html

   (2) https://github.com/python/cpython/issues/88048


File: python.info,  Node: Notable security feature in 3 9 14,  Next: Notable changes in 3 9 17,  Prev: Notable changes in Python 3 9 5,  Up: What’s New In Python 3 9

1.5.17 Notable security feature in 3.9.14
-----------------------------------------

Converting between *note int: 257. and *note str: 44f. in bases other
than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10
(decimal) now raises a *note ValueError: 202. if the number of digits in
string form is above a limit to avoid potential denial of service
attacks due to the algorithmic complexity.  This is a mitigation for CVE
2020-10735(1).  This limit can be configured or disabled by environment
variable, command line flag, or *note sys: d9. APIs.  See the *note
integer string conversion length limitation: 5f8. documentation.  The
default limit is 4300 digits in string form.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: Notable changes in 3 9 17,  Prev: Notable security feature in 3 9 14,  Up: What’s New In Python 3 9

1.5.18 Notable changes in 3.9.17
--------------------------------

* Menu:

* tarfile: tarfile<4>.


File: python.info,  Node: tarfile<4>,  Up: Notable changes in 3 9 17

1.5.18.1 tarfile
................

   * The extraction methods in *note tarfile: de, and *note
     shutil.unpack_archive(): 46e, have a new a 'filter' argument that
     allows limiting tar features than may be surprising or dangerous,
     such as creating files outside the destination directory.  See
     *note Extraction filters: 46f. for details.  In Python 3.12, use
     without the 'filter' argument will show a *note DeprecationWarning:
     1a5.  In Python 3.14, the default will switch to ‘'data'’.
     (Contributed by Petr Viktorin in PEP 706(1).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0706/


File: python.info,  Node: What’s New In Python 3 8,  Next: What’s New In Python 3 7,  Prev: What’s New In Python 3 9,  Up: What’s New in Python

1.6 What’s New In Python 3.8
============================


Editor: Raymond Hettinger

This article explains the new features in Python 3.8, compared to 3.7.
Python 3.8 was released on October 14, 2019.  For full details, see the
*note changelog: 13c.

* Menu:

* Summary – Release highlights: Summary – Release highlights<5>.
* New Features: New Features<11>.
* Other Language Changes: Other Language Changes<6>.
* New Modules: New Modules<6>.
* Improved Modules: Improved Modules<6>.
* Optimizations: Optimizations<6>.
* Build and C API Changes::
* Deprecated: Deprecated<8>.
* API and Feature Removals::
* Porting to Python 3.8: Porting to Python 3 8.
* Notable changes in Python 3.8.1: Notable changes in Python 3 8 1.
* Notable changes in Python 3.8.2: Notable changes in Python 3 8 2.
* Notable changes in Python 3.8.3: Notable changes in Python 3 8 3.
* Notable changes in Python 3.8.8: Notable changes in Python 3 8 8.
* Notable changes in Python 3.8.9: Notable changes in Python 3 8 9.
* Notable changes in Python 3.8.10: Notable changes in Python 3 8 10.
* Notable changes in Python 3.8.10: Notable changes in Python 3 8 10<2>.
* Notable changes in Python 3.8.12: Notable changes in Python 3 8 12.
* Notable security feature in 3.8.14: Notable security feature in 3 8 14.
* Notable changes in 3.8.17: Notable changes in 3 8 17.


File: python.info,  Node: Summary – Release highlights<5>,  Next: New Features<11>,  Up: What’s New In Python 3 8

1.6.1 Summary – Release highlights
----------------------------------


File: python.info,  Node: New Features<11>,  Next: Other Language Changes<6>,  Prev: Summary – Release highlights<5>,  Up: What’s New In Python 3 8

1.6.2 New Features
------------------

* Menu:

* Assignment expressions::
* Positional-only parameters::
* Parallel filesystem cache for compiled bytecode files::
* Debug build uses the same ABI as release build::
* f-strings support = for self-documenting expressions and debugging::
* PEP 578; Python Runtime Audit Hooks: PEP 578 Python Runtime Audit Hooks.
* PEP 587; Python Initialization Configuration: PEP 587 Python Initialization Configuration.
* PEP 590; Vectorcall; a fast calling protocol for CPython: PEP 590 Vectorcall a fast calling protocol for CPython.
* Pickle protocol 5 with out-of-band data buffers::


File: python.info,  Node: Assignment expressions,  Next: Positional-only parameters,  Up: New Features<11>

1.6.2.1 Assignment expressions
..............................

There is new syntax ‘:=’ that assigns values to variables as part of a
larger expression.  It is affectionately known as “the walrus operator”
due to its resemblance to the eyes and tusks of a walrus(1).

In this example, the assignment expression helps avoid calling *note
len(): 631. twice:

     if (n := len(a)) > 10:
         print(f"List is too long ({n} elements, expected <= 10)")

A similar benefit arises during regular expression matching where match
objects are needed twice, once to test whether a match occurred and
another to extract a subgroup:

     discount = 0.0
     if (mo := re.search(r'(\d+)% discount', advertisement)):
         discount = float(mo.group(1)) / 100.0

The operator is also useful with while-loops that compute a value to
test loop termination and then need that same value again in the body of
the loop:

     # Loop over fixed length blocks
     while (block := f.read(256)) != '':
         process(block)

Another motivating use case arises in list comprehensions where a value
computed in a filtering condition is also needed in the expression body:

     [clean_name.title() for name in names
      if (clean_name := normalize('NFC', name)) in allowed_names]

Try to limit use of the walrus operator to clean cases that reduce
complexity and improve readability.

See PEP 572(2) for a full description.

(Contributed by Emily Morehouse in bpo-35224(3).)

   ---------- Footnotes ----------

   (1) 
https://en.wikipedia.org/wiki/Walrus#/media/File:Pacific_Walrus_-_Bull_(8247646168).jpg

   (2) https://peps.python.org/pep-0572/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35224


File: python.info,  Node: Positional-only parameters,  Next: Parallel filesystem cache for compiled bytecode files,  Prev: Assignment expressions,  Up: New Features<11>

1.6.2.2 Positional-only parameters
..................................

There is a new function parameter syntax ‘/’ to indicate that some
function parameters must be specified positionally and cannot be used as
keyword arguments.  This is the same notation shown by ‘help()’ for C
functions annotated with Larry Hastings’ Argument Clinic(1) tool.

In the following example, parameters 'a' and 'b' are positional-only,
while 'c' or 'd' can be positional or keyword, and 'e' or 'f' are
required to be keywords:

     def f(a, b, /, c, d, *, e, f):
         print(a, b, c, d, e, f)

The following is a valid call:

     f(10, 20, 30, d=40, e=50, f=60)

However, these are invalid calls:

     f(10, b=20, c=30, d=40, e=50, f=60)   # b cannot be a keyword argument
     f(10, 20, 30, 40, 50, f=60)           # e must be a keyword argument

One use case for this notation is that it allows pure Python functions
to fully emulate behaviors of existing C coded functions.  For example,
the built-in *note divmod(): 9ac. function does not accept keyword
arguments:

     def divmod(a, b, /):
         "Emulate the built in divmod() function"
         return (a // b, a % b)

Another use case is to preclude keyword arguments when the parameter
name is not helpful.  For example, the builtin *note len(): 631.
function has the signature ‘len(obj, /)’.  This precludes awkward calls
such as:

     len(obj='hello')  # The "obj" keyword argument impairs readability

A further benefit of marking a parameter as positional-only is that it
allows the parameter name to be changed in the future without risk of
breaking client code.  For example, in the *note statistics: d2. module,
the parameter name 'dist' may be changed in the future.  This was made
possible with the following function specification:

     def quantiles(dist, /, *, n=4, method='exclusive')
         ...

Since the parameters to the left of ‘/’ are not exposed as possible
keywords, the parameters names remain available for use in ‘**kwargs’:

     >>> def f(a, b, /, **kwargs):
     ...     print(a, b, kwargs)
     ...
     >>> f(10, 20, a=1, b=2, c=3)         # a and b are used in two ways
     10 20 {'a': 1, 'b': 2, 'c': 3}

This greatly simplifies the implementation of functions and methods that
need to accept arbitrary keyword arguments.  For example, here is an
excerpt from code in the *note collections: 1d. module:

     class Counter(dict):

         def __init__(self, iterable=None, /, **kwds):
             # Note "iterable" is a possible keyword argument

See PEP 570(2) for a full description.

(Contributed by Pablo Galindo in bpo-36540(3).)

   ---------- Footnotes ----------

   (1) https://devguide.python.org/development-tools/clinic/

   (2) https://peps.python.org/pep-0570/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36540


File: python.info,  Node: Parallel filesystem cache for compiled bytecode files,  Next: Debug build uses the same ABI as release build,  Prev: Positional-only parameters,  Up: New Features<11>

1.6.2.3 Parallel filesystem cache for compiled bytecode files
.............................................................

The new *note PYTHONPYCACHEPREFIX: 9ae. setting (also available as *note
-X: 176. ‘pycache_prefix’) configures the implicit bytecode cache to use
a separate parallel filesystem tree, rather than the default
‘__pycache__’ subdirectories within each source directory.

The location of the cache is reported in *note sys.pycache_prefix: 9af.
(*note None: 678. indicates the default location in ‘__pycache__’
subdirectories).

(Contributed by Carl Meyer in bpo-33499(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33499


File: python.info,  Node: Debug build uses the same ABI as release build,  Next: f-strings support = for self-documenting expressions and debugging,  Prev: Parallel filesystem cache for compiled bytecode files,  Up: New Features<11>

1.6.2.4 Debug build uses the same ABI as release build
......................................................

The ABI of Python *note debug builds: 1f9. is now compatible with Python
release builds.  On Unix, when Python is built in debug mode, it is now
possible to load C extensions built in release mode and C extensions
built using the stable ABI. The inverse is not true, as debug builds
expose additional symbols not available in release builds.

Defining the ‘Py_DEBUG’ macro no longer implies the ‘Py_TRACE_REFS’
macro, which introduces the only ABI incompatibility.  The
‘Py_TRACE_REFS’ macro, which adds the *note sys.getobjects(): 42a.
function and the *note PYTHONDUMPREFS: 9b1. environment variable, can be
set using the new *note ./configure -with-trace-refs: 398. build option.
(Contributed by Victor Stinner in bpo-36465(1).)

On Unix, C extensions are no longer linked to libpython except on
Android and Cygwin.  It is now possible for a statically linked Python
to load a C extension built using a shared library Python.  (Contributed
by Victor Stinner in bpo-21536(2).)

On Unix, when Python is built in debug mode, import now also looks for C
extensions compiled in release mode and for C extensions compiled with
the stable ABI. (Contributed by Victor Stinner in bpo-36722(3).)

To embed Python into an application, a new ‘--embed’ option must be
passed to ‘python3-config --libs --embed’ to get ‘-lpython3.8’ (link the
application to libpython).  To support both 3.8 and older, try
‘python3-config --libs --embed’ first and fallback to ‘python3-config
--libs’ (without ‘--embed’) if the previous command fails.

Add a pkg-config ‘python-3.8-embed’ module to embed Python into an
application: ‘pkg-config python-3.8-embed --libs’ includes
‘-lpython3.8’.  To support both 3.8 and older, try ‘pkg-config
python-X.Y-embed --libs’ first and fallback to ‘pkg-config python-X.Y
--libs’ (without ‘--embed’) if the previous command fails (replace ‘X.Y’
with the Python version).

On the other hand, ‘pkg-config python3.8 --libs’ no longer contains
‘-lpython3.8’.  C extensions must not be linked to libpython (except on
Android and Cygwin, whose cases are handled by the script); this change
is backward incompatible on purpose.  (Contributed by Victor Stinner in
bpo-36721(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36465

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21536

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36722

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36721


File: python.info,  Node: f-strings support = for self-documenting expressions and debugging,  Next: PEP 578 Python Runtime Audit Hooks,  Prev: Debug build uses the same ABI as release build,  Up: New Features<11>

1.6.2.5 f-strings support ‘=’ for self-documenting expressions and debugging
............................................................................

Added an ‘=’ specifier to *note f-string: 439.s.  An f-string such as
‘f'{expr=}'’ will expand to the text of the expression, an equal sign,
then the representation of the evaluated expression.  For example:

     >>> import datetime as dt
     >>> user = 'eric_idle'
     >>> member_since = dt.date(1975, 7, 31)
     >>> f'{user=} {member_since=}'
     "user='eric_idle' member_since=datetime.date(1975, 7, 31)"

The usual *note f-string format specifiers: 9b4. allow more control over
how the result of the expression is displayed:

     >>> delta = dt.date.today() - member_since
     >>> f'{user=!s}  {delta.days=:,d}'
     'user=eric_idle  delta.days=16,075'

The ‘=’ specifier will display the whole expression so that calculations
can be shown:

     >>> print(f'{theta=}  {cos(radians(theta))=:.3f}')
     theta=30  cos(radians(theta))=0.866

(Contributed by Eric V. Smith and Larry Hastings in bpo-36817(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36817


File: python.info,  Node: PEP 578 Python Runtime Audit Hooks,  Next: PEP 587 Python Initialization Configuration,  Prev: f-strings support = for self-documenting expressions and debugging,  Up: New Features<11>

1.6.2.6 PEP 578: Python Runtime Audit Hooks
...........................................

The PEP adds an Audit Hook and Verified Open Hook.  Both are available
from Python and native code, allowing applications and frameworks
written in pure Python code to take advantage of extra notifications,
while also allowing embedders or system administrators to deploy builds
of Python where auditing is always enabled.

See PEP 578(1) for full details.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0578/


File: python.info,  Node: PEP 587 Python Initialization Configuration,  Next: PEP 590 Vectorcall a fast calling protocol for CPython,  Prev: PEP 578 Python Runtime Audit Hooks,  Up: New Features<11>

1.6.2.7 PEP 587: Python Initialization Configuration
....................................................

The PEP 587(1) adds a new C API to configure the Python Initialization
providing finer control on the whole configuration and better error
reporting.

New structures:

   * *note PyConfig: 3a9.

   * *note PyPreConfig: 9b7.

   * *note PyStatus: 9b8.

   * *note PyWideStringList: 9b9.

New functions:

   * *note PyConfig_Clear(): 9ba.

   * *note PyConfig_InitIsolatedConfig(): 9bb.

   * *note PyConfig_InitPythonConfig(): 9bc.

   * *note PyConfig_Read(): 793.

   * *note PyConfig_SetArgv(): 9bd.

   * *note PyConfig_SetBytesArgv(): 9be.

   * *note PyConfig_SetBytesString(): 9bf.

   * *note PyConfig_SetString(): 9c0.

   * *note PyPreConfig_InitIsolatedConfig(): 9c1.

   * *note PyPreConfig_InitPythonConfig(): 9c2.

   * *note PyStatus_Error(): 9c3.

   * *note PyStatus_Exception(): 9c4.

   * *note PyStatus_Exit(): 9c5.

   * *note PyStatus_IsError(): 9c6.

   * *note PyStatus_IsExit(): 9c7.

   * *note PyStatus_NoMemory(): 9c8.

   * *note PyStatus_Ok(): 9c9.

   * *note PyWideStringList_Append(): 9ca.

   * *note PyWideStringList_Insert(): 9cb.

   * *note Py_BytesMain(): 9cc.

   * *note Py_ExitStatusException(): 9cd.

   * *note Py_InitializeFromConfig(): 3c8.

   * *note Py_PreInitialize(): 3ee.

   * *note Py_PreInitializeFromArgs(): 9ce.

   * *note Py_PreInitializeFromBytesArgs(): 9cf.

   * *note Py_RunMain(): 9d0.

This PEP also adds ‘_PyRuntimeState.preconfig’ (*note PyPreConfig: 9b7.
type) and ‘PyInterpreterState.config’ (*note PyConfig: 3a9. type) fields
to these internal structures.  ‘PyInterpreterState.config’ becomes the
new reference configuration, replacing global configuration variables
and other private variables.

See *note Python Initialization Configuration: 3aa. for the
documentation.

See PEP 587(2) for a full description.

(Contributed by Victor Stinner in bpo-36763(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0587/

   (2) https://peps.python.org/pep-0587/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36763


File: python.info,  Node: PEP 590 Vectorcall a fast calling protocol for CPython,  Next: Pickle protocol 5 with out-of-band data buffers,  Prev: PEP 587 Python Initialization Configuration,  Up: New Features<11>

1.6.2.8 PEP 590: Vectorcall: a fast calling protocol for CPython
................................................................

*note The Vectorcall Protocol: 555. is added to the Python/C API. It is
meant to formalize existing optimizations which were already done for
various classes.  Any *note static type: 782. implementing a callable
can use this protocol.

This is currently provisional.  The aim is to make it fully public in
Python 3.9.

See PEP 590(1) for a full description.

(Contributed by Jeroen Demeyer, Mark Shannon and Petr Viktorin in
bpo-36974(2).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0590/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36974


File: python.info,  Node: Pickle protocol 5 with out-of-band data buffers,  Prev: PEP 590 Vectorcall a fast calling protocol for CPython,  Up: New Features<11>

1.6.2.9 Pickle protocol 5 with out-of-band data buffers
.......................................................

When *note pickle: a6. is used to transfer large data between Python
processes in order to take advantage of multi-core or multi-machine
processing, it is important to optimize the transfer by reducing memory
copies, and possibly by applying custom techniques such as
data-dependent compression.

The *note pickle: a6. protocol 5 introduces support for out-of-band
buffers where PEP 3118(1)-compatible data can be transmitted separately
from the main pickle stream, at the discretion of the communication
layer.

See PEP 574(2) for a full description.

(Contributed by Antoine Pitrou in bpo-36785(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/

   (2) https://peps.python.org/pep-0574/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36785


File: python.info,  Node: Other Language Changes<6>,  Next: New Modules<6>,  Prev: New Features<11>,  Up: What’s New In Python 3 8

1.6.3 Other Language Changes
----------------------------

   * A *note continue: 9d4. statement was illegal in the *note finally:
     9d5. clause due to a problem with the implementation.  In Python
     3.8 this restriction was lifted.  (Contributed by Serhiy Storchaka
     in bpo-32489(1).)

   * The *note bool: 46b, *note int: 257, and *note fractions.Fraction:
     1e7. types now have an *note as_integer_ratio(): 9d6. method like
     that found in *note float: 2f7. and *note decimal.Decimal: 29d.
     This minor API extension makes it possible to write ‘numerator,
     denominator = x.as_integer_ratio()’ and have it work across
     multiple numeric types.  (Contributed by Lisa Roach in bpo-33073(2)
     and Raymond Hettinger in bpo-37819(3).)

   * Constructors of *note int: 257, *note float: 2f7. and *note
     complex: 2f8. will now use the *note __index__(): 720. special
     method, if available and the corresponding method *note __int__():
     71f, *note __float__(): 9d7. or *note __complex__(): 5ea. is not
     available.  (Contributed by Serhiy Storchaka in bpo-20092(4).)

   * Added support of ‘\N{NAME}’ escapes in *note regular expressions:
     b9.:

          >>> notice = 'Copyright © 2019'
          >>> copyright_year_pattern = re.compile(r'\N{copyright sign}\s*(\d{4})')
          >>> int(copyright_year_pattern.search(notice).group(1))
          2019

     (Contributed by Jonathan Eunice and Serhiy Storchaka in
     bpo-30688(5).)

   * Dict and dictviews are now iterable in reversed insertion order
     using *note reversed(): 86c.  (Contributed by Rémi Lapeyre in
     bpo-33462(6).)

   * The syntax allowed for keyword names in function calls was further
     restricted.  In particular, ‘f((keyword)=arg)’ is no longer
     allowed.  It was never intended to permit more than a bare name on
     the left-hand side of a keyword argument assignment term.
     (Contributed by Benjamin Peterson in bpo-34641(7).)

   * Generalized iterable unpacking in *note yield: 9d8. and *note
     return: 9d9. statements no longer requires enclosing parentheses.
     This brings the 'yield' and 'return' syntax into better agreement
     with normal assignment syntax:

          >>> def parse(family):
                  lastname, *members = family.split()
                  return lastname.upper(), *members

          >>> parse('simpsons homer marge bart lisa maggie')
          ('SIMPSONS', 'homer', 'marge', 'bart', 'lisa', 'maggie')

     (Contributed by David Cuthbert and Jordan Chapman in bpo-32117(8).)

   * When a comma is missed in code such as ‘[(10, 20) (30, 40)]’, the
     compiler displays a *note SyntaxWarning: 469. with a helpful
     suggestion.  This improves on just having a *note TypeError: 2c3.
     indicating that the first tuple was not callable.  (Contributed by
     Serhiy Storchaka in bpo-15248(9).)

   * Arithmetic operations between subclasses of *note datetime.date:
     1cd. or *note datetime.datetime: 1cc. and *note datetime.timedelta:
     9da. objects now return an instance of the subclass, rather than
     the base class.  This also affects the return type of operations
     whose implementation (directly or indirectly) uses
     ‘datetime.timedelta’ arithmetic, such as *note astimezone(): 9db.
     (Contributed by Paul Ganssle in bpo-32417(10).)

   * When the Python interpreter is interrupted by Ctrl-C (SIGINT) and
     the resulting *note KeyboardInterrupt: 9dc. exception is not
     caught, the Python process now exits via a SIGINT signal or with
     the correct exit code such that the calling process can detect that
     it died due to a Ctrl-C. Shells on POSIX and Windows use this to
     properly terminate scripts in interactive sessions.  (Contributed
     by Google via Gregory P. Smith in bpo-1054041(11).)

   * Some advanced styles of programming require updating the *note
     types.CodeType: 2df. object for an existing function.  Since code
     objects are immutable, a new code object needs to be created, one
     that is modeled on the existing code object.  With 19 parameters,
     this was somewhat tedious.  Now, the new ‘replace()’ method makes
     it possible to create a clone with a few altered parameters.

     Here’s an example that alters the *note statistics.mean(): 6d5.
     function to prevent the 'data' parameter from being used as a
     keyword argument:

          >>> from statistics import mean
          >>> mean(data=[10, 20, 90])
          40
          >>> mean.__code__ = mean.__code__.replace(co_posonlyargcount=1)
          >>> mean(data=[10, 20, 90])
          Traceback (most recent call last):
            ...
          TypeError: mean() got some positional-only arguments passed as keyword arguments: 'data'

     (Contributed by Victor Stinner in bpo-37032(12).)

   * For integers, the three-argument form of the *note pow(): 9dd.
     function now permits the exponent to be negative in the case where
     the base is relatively prime to the modulus.  It then computes a
     modular inverse to the base when the exponent is ‘-1’, and a
     suitable power of that inverse for other negative exponents.  For
     example, to compute the modular multiplicative inverse(13) of 38
     modulo 137, write:

          >>> pow(38, -1, 137)
          119
          >>> 119 * 38 % 137
          1

     Modular inverses arise in the solution of linear Diophantine
     equations(14).  For example, to find integer solutions for ‘4258𝑥 +
     147𝑦 = 369’, first rewrite as ‘4258𝑥 ≡ 369 (mod 147)’ then solve:

          >>> x = 369 * pow(4258, -1, 147) % 147
          >>> y = (4258 * x - 369) // -147
          >>> 4258 * x + 147 * y
          369

     (Contributed by Mark Dickinson in bpo-36027(15).)

   * Dict comprehensions have been synced-up with dict literals so that
     the key is computed first and the value second:

          >>> # Dict comprehension
          >>> cast = {input('role? '): input('actor? ') for i in range(2)}
          role? King Arthur
          actor? Chapman
          role? Black Knight
          actor? Cleese

          >>> # Dict literal
          >>> cast = {input('role? '): input('actor? ')}
          role? Sir Robin
          actor? Eric Idle

     The guaranteed execution order is helpful with assignment
     expressions because variables assigned in the key expression will
     be available in the value expression:

          >>> names = ['Martin von Löwis', 'Łukasz Langa', 'Walter Dörwald']
          >>> {(n := normalize('NFC', name)).casefold() : n for name in names}
          {'martin von löwis': 'Martin von Löwis',
           'łukasz langa': 'Łukasz Langa',
           'walter dörwald': 'Walter Dörwald'}

     (Contributed by Jörn Heissler in bpo-35224(16).)

   * The *note object.__reduce__(): 9de. method can now return a tuple
     from two to six elements long.  Formerly, five was the limit.  The
     new, optional sixth element is a callable with a ‘(obj, state)’
     signature.  This allows the direct control over the state-updating
     behavior of a specific object.  If not 'None', this callable will
     have priority over the object’s *note __setstate__(): 9df. method.
     (Contributed by Pierre Glaser and Olivier Grisel in bpo-35900(17).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32489

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33073

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37819

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20092

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30688

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33462

   (7) https://bugs.python.org/issue?@action=redirect&bpo=34641

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32117

   (9) https://bugs.python.org/issue?@action=redirect&bpo=15248

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32417

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1054041

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37032

   (13) https://en.wikipedia.org/wiki/Modular_multiplicative_inverse

   (14) https://en.wikipedia.org/wiki/Diophantine_equation

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36027

   (16) https://bugs.python.org/issue?@action=redirect&bpo=35224

   (17) https://bugs.python.org/issue?@action=redirect&bpo=35900


File: python.info,  Node: New Modules<6>,  Next: Improved Modules<6>,  Prev: Other Language Changes<6>,  Up: What’s New In Python 3 8

1.6.4 New Modules
-----------------

   * The new *note importlib.metadata: 7a. module provides (provisional)
     support for reading metadata from third-party packages.  For
     example, it can extract an installed package’s version number, list
     of entry points, and more:

          >>> # Note following example requires that the popular "requests"
          >>> # package has been installed.
          >>>
          >>> from importlib.metadata import version, requires, files
          >>> version('requests')
          '2.22.0'
          >>> list(requires('requests'))
          ['chardet (<3.1.0,>=3.0.2)']
          >>> list(files('requests'))[:5]
          [PackagePath('requests-2.22.0.dist-info/INSTALLER'),
           PackagePath('requests-2.22.0.dist-info/LICENSE'),
           PackagePath('requests-2.22.0.dist-info/METADATA'),
           PackagePath('requests-2.22.0.dist-info/RECORD'),
           PackagePath('requests-2.22.0.dist-info/WHEEL')]

     (Contributed by Barry Warsaw and Jason R. Coombs in bpo-34632(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34632


File: python.info,  Node: Improved Modules<6>,  Next: Optimizations<6>,  Prev: New Modules<6>,  Up: What’s New In Python 3 8

1.6.5 Improved Modules
----------------------

* Menu:

* ast: ast<3>.
* asyncio: asyncio<6>.
* builtins: builtins<2>.
* collections::
* cProfile::
* csv: csv<2>.
* curses: curses<3>.
* ctypes: ctypes<2>.
* datetime: datetime<3>.
* functools: functools<2>.
* gc: gc<3>.
* gettext::
* gzip: gzip<3>.
* IDLE and idlelib: IDLE and idlelib<4>.
* inspect: inspect<5>.
* io: io<3>.
* itertools: itertools<4>.
* json.tool: json tool.
* logging: logging<2>.
* math: math<5>.
* mmap: mmap<2>.
* multiprocessing: multiprocessing<3>.
* os: os<6>.
* os.path: os path<5>.
* pathlib: pathlib<7>.
* pickle::
* plistlib::
* pprint: pprint<3>.
* py_compile: py_compile<2>.
* shlex::
* shutil: shutil<4>.
* socket: socket<4>.
* ssl: ssl<4>.
* statistics: statistics<4>.
* sys: sys<7>.
* tarfile: tarfile<5>.
* threading: threading<4>.
* tokenize: tokenize<2>.
* tkinter: tkinter<4>.
* time: time<4>.
* typing: typing<8>.
* unicodedata: unicodedata<5>.
* unittest: unittest<6>.
* venv: venv<4>.
* weakref::
* xml: xml<4>.
* xmlrpc::


File: python.info,  Node: ast<3>,  Next: asyncio<6>,  Up: Improved Modules<6>

1.6.5.1 ast
...........

AST nodes now have ‘end_lineno’ and ‘end_col_offset’ attributes, which
give the precise location of the end of the node.  (This only applies to
nodes that have ‘lineno’ and ‘col_offset’ attributes.)

New function *note ast.get_source_segment(): 9e3. returns the source
code for a specific AST node.

(Contributed by Ivan Levkivskyi in bpo-33416(1).)

The *note ast.parse(): 1a8. function has some new flags:

   * ‘type_comments=True’ causes it to return the text of PEP 484(2) and
     PEP 526(3) type comments associated with certain AST nodes;

   * ‘mode='func_type'’ can be used to parse PEP 484(4) “signature type
     comments” (returned for function definition AST nodes);

   * ‘feature_version=(3, N)’ allows specifying an earlier Python 3
     version.  For example, ‘feature_version=(3, 4)’ will treat *note
     async: 735. and *note await: 1b9. as non-reserved words.

(Contributed by Guido van Rossum in bpo-35766(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33416

   (2) https://peps.python.org/pep-0484/

   (3) https://peps.python.org/pep-0526/

   (4) https://peps.python.org/pep-0484/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35766


File: python.info,  Node: asyncio<6>,  Next: builtins<2>,  Prev: ast<3>,  Up: Improved Modules<6>

1.6.5.2 asyncio
...............

*note asyncio.run(): 47f. has graduated from the provisional to stable
API. This function can be used to execute a *note coroutine: 494. and
return the result while automatically managing the event loop.  For
example:

     import asyncio

     async def main():
         await asyncio.sleep(0)
         return 42

     asyncio.run(main())

This is 'roughly' equivalent to:

     import asyncio

     async def main():
         await asyncio.sleep(0)
         return 42

     loop = asyncio.new_event_loop()
     asyncio.set_event_loop(loop)
     try:
         loop.run_until_complete(main())
     finally:
         asyncio.set_event_loop(None)
         loop.close()

The actual implementation is significantly more complex.  Thus, *note
asyncio.run(): 47f. should be the preferred way of running asyncio
programs.

(Contributed by Yury Selivanov in bpo-32314(1).)

Running ‘python -m asyncio’ launches a natively async REPL. This allows
rapid experimentation with code that has a top-level *note await: 1b9.
There is no longer a need to directly call ‘asyncio.run()’ which would
spawn a new event loop on every invocation:

     $ python -m asyncio
     asyncio REPL 3.8.0
     Use "await" directly instead of "asyncio.run()".
     Type "help", "copyright", "credits" or "license" for more information.
     >>> import asyncio
     >>> await asyncio.sleep(10, result='hello')
     hello

(Contributed by Yury Selivanov in bpo-37028(2).)

The exception *note asyncio.CancelledError: 1b8. now inherits from *note
BaseException: 5be. rather than *note Exception: 9e5. and no longer
inherits from *note concurrent.futures.CancelledError: 9e6.
(Contributed by Yury Selivanov in bpo-32528(3).)

On Windows, the default event loop is now *note ProactorEventLoop: 60c.
(Contributed by Victor Stinner in bpo-34687(4).)

*note ProactorEventLoop: 60c. now also supports UDP. (Contributed by
Adam Meily and Andrew Svetlov in bpo-29883(5).)

*note ProactorEventLoop: 60c. can now be interrupted by *note
KeyboardInterrupt: 9dc. (“CTRL+C”).  (Contributed by Vladimir Matveev in
bpo-23057(6).)

Added *note asyncio.Task.get_coro(): 9e7. for getting the wrapped
coroutine within an *note asyncio.Task: 1be.  (Contributed by Alex
Grönholm in bpo-36999(7).)

Asyncio tasks can now be named, either by passing the ‘name’ keyword
argument to *note asyncio.create_task(): 1bf. or the *note
create_task(): 1c0. event loop method, or by calling the *note
set_name(): 9e8. method on the task object.  The task name is visible in
the ‘repr()’ output of *note asyncio.Task: 1be. and can also be
retrieved using the *note get_name(): 9e9. method.  (Contributed by Alex
Grönholm in bpo-34270(8).)

Added support for Happy Eyeballs(9) to *note
asyncio.loop.create_connection(): 606.  To specify the behavior, two new
parameters have been added: 'happy_eyeballs_delay' and 'interleave'.
The Happy Eyeballs algorithm improves responsiveness in applications
that support IPv4 and IPv6 by attempting to simultaneously connect using
both.  (Contributed by twisteroid ambassador in bpo-33530(10).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32314

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37028

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32528

   (4) https://bugs.python.org/issue?@action=redirect&bpo=34687

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29883

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23057

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36999

   (8) https://bugs.python.org/issue?@action=redirect&bpo=34270

   (9) https://en.wikipedia.org/wiki/Happy_Eyeballs

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33530


File: python.info,  Node: builtins<2>,  Next: collections,  Prev: asyncio<6>,  Up: Improved Modules<6>

1.6.5.3 builtins
................

The *note compile(): 192. built-in has been improved to accept the
‘ast.PyCF_ALLOW_TOP_LEVEL_AWAIT’ flag.  With this new flag passed,
‘compile()’ will allow top-level ‘await’, ‘async for’ and ‘async with’
constructs that are usually considered invalid syntax.  Asynchronous
code object marked with the ‘CO_COROUTINE’ flag may then be returned.
(Contributed by Matthias Bussonnier in bpo-34616(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34616


File: python.info,  Node: collections,  Next: cProfile,  Prev: builtins<2>,  Up: Improved Modules<6>

1.6.5.4 collections
...................

The *note _asdict(): 9ec. method for *note collections.namedtuple():
1ca. now returns a *note dict: 256. instead of a *note
collections.OrderedDict: 5de.  This works because regular dicts have
guaranteed ordering since Python 3.7.  If the extra features of
‘OrderedDict’ are required, the suggested remediation is to cast the
result to the desired type: ‘OrderedDict(nt._asdict())’.  (Contributed
by Raymond Hettinger in bpo-35864(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35864


File: python.info,  Node: cProfile,  Next: csv<2>,  Prev: collections,  Up: Improved Modules<6>

1.6.5.5 cProfile
................

The *note cProfile.Profile: 9ee. class can now be used as a context
manager.  Profile a block of code by running:

     import cProfile

     with cProfile.Profile() as profiler:
           # code to be profiled
           ...

(Contributed by Scott Sanderson in bpo-29235(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29235


File: python.info,  Node: csv<2>,  Next: curses<3>,  Prev: cProfile,  Up: Improved Modules<6>

1.6.5.6 csv
...........

The *note csv.DictReader: 9f0. now returns instances of *note dict: 256.
instead of a *note collections.OrderedDict: 5de.  The tool is now faster
and uses less memory while still preserving the field order.
(Contributed by Michael Selik in bpo-34003(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34003


File: python.info,  Node: curses<3>,  Next: ctypes<2>,  Prev: csv<2>,  Up: Improved Modules<6>

1.6.5.7 curses
..............

Added a new variable holding structured version information for the
underlying ncurses library: *note ncurses_version: 9f2.  (Contributed by
Serhiy Storchaka in bpo-31680(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31680


File: python.info,  Node: ctypes<2>,  Next: datetime<3>,  Prev: curses<3>,  Up: Improved Modules<6>

1.6.5.8 ctypes
..............

On Windows, *note CDLL: 9f4. and subclasses now accept a 'winmode'
parameter to specify flags for the underlying ‘LoadLibraryEx’ call.  The
default flags are set to only load DLL dependencies from trusted
locations, including the path where the DLL is stored (if a full or
partial path is used to load the initial DLL) and paths added by *note
add_dll_directory(): 9f5.  (Contributed by Steve Dower in bpo-36085(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36085


File: python.info,  Node: datetime<3>,  Next: functools<2>,  Prev: ctypes<2>,  Up: Improved Modules<6>

1.6.5.9 datetime
................

Added new alternate constructors *note datetime.date.fromisocalendar():
9f7. and *note datetime.datetime.fromisocalendar(): 9f8, which construct
*note date: 1cd. and *note datetime: 1cc. objects respectively from ISO
year, week number, and weekday; these are the inverse of each class’s
‘isocalendar’ method.  (Contributed by Paul Ganssle in bpo-36004(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36004


File: python.info,  Node: functools<2>,  Next: gc<3>,  Prev: datetime<3>,  Up: Improved Modules<6>

1.6.5.10 functools
..................

*note functools.lru_cache(): 9fa. can now be used as a straight
decorator rather than as a function returning a decorator.  So both of
these are now supported:

     @lru_cache
     def f(x):
         ...

     @lru_cache(maxsize=256)
     def f(x):
         ...

(Contributed by Raymond Hettinger in bpo-36772(1).)

Added a new *note functools.cached_property(): 544. decorator, for
computed properties cached for the life of the instance.

     import functools
     import statistics

     class Dataset:
        def __init__(self, sequence_of_numbers):
           self.data = sequence_of_numbers

        @functools.cached_property
        def variance(self):
           return statistics.variance(self.data)

(Contributed by Carl Meyer in bpo-21145(2))

Added a new *note functools.singledispatchmethod(): 9fb. decorator that
converts methods into *note generic functions: 9fc. using *note single
dispatch: 9fd.:

     from functools import singledispatchmethod
     from contextlib import suppress

     class TaskManager:

         def __init__(self, tasks):
             self.tasks = list(tasks)

         @singledispatchmethod
         def discard(self, value):
             with suppress(ValueError):
                 self.tasks.remove(value)

         @discard.register(list)
         def _(self, tasks):
             targets = set(tasks)
             self.tasks = [x for x in self.tasks if x not in targets]

(Contributed by Ethan Smith in bpo-32380(3))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36772

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21145

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32380


File: python.info,  Node: gc<3>,  Next: gettext,  Prev: functools<2>,  Up: Improved Modules<6>

1.6.5.11 gc
...........

*note get_objects(): 809. can now receive an optional 'generation'
parameter indicating a generation to get objects from.  (Contributed by
Pablo Galindo in bpo-36016(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36016


File: python.info,  Node: gettext,  Next: gzip<3>,  Prev: gc<3>,  Up: Improved Modules<6>

1.6.5.12 gettext
................

Added *note pgettext(): a00. and its variants.  (Contributed by Franz
Glasner, Éric Araujo, and Cheryl Sabella in bpo-2504(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2504


File: python.info,  Node: gzip<3>,  Next: IDLE and idlelib<4>,  Prev: gettext,  Up: Improved Modules<6>

1.6.5.13 gzip
.............

Added the 'mtime' parameter to *note gzip.compress(): 641. for
reproducible output.  (Contributed by Guo Ci Teo in bpo-34898(1).)

A *note BadGzipFile: a02. exception is now raised instead of *note
OSError: 41a. for certain types of invalid or corrupt gzip files.
(Contributed by Filip Gruszczyński, Michele Orrù, and Zackery Spytz in
bpo-6584(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34898

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6584


File: python.info,  Node: IDLE and idlelib<4>,  Next: inspect<5>,  Prev: gzip<3>,  Up: Improved Modules<6>

1.6.5.14 IDLE and idlelib
.........................

Output over N lines (50 by default) is squeezed down to a button.  N can
be changed in the PyShell section of the General page of the Settings
dialog.  Fewer, but possibly extra long, lines can be squeezed by right
clicking on the output.  Squeezed output can be expanded in place by
double-clicking the button or into the clipboard or a separate window by
right-clicking the button.  (Contributed by Tal Einat in
bpo-1529353(1).)

Add “Run Customized” to the Run menu to run a module with customized
settings.  Any command line arguments entered are added to sys.argv.
They also re-appear in the box for the next customized run.  One can
also suppress the normal Shell main module restart.  (Contributed by
Cheryl Sabella, Terry Jan Reedy, and others in bpo-5680(2) and
bpo-37627(3).)

Added optional line numbers for IDLE editor windows.  Windows open
without line numbers unless set otherwise in the General tab of the
configuration dialog.  Line numbers for an existing window are shown and
hidden in the Options menu.  (Contributed by Tal Einat and Saimadhav
Heblikar in bpo-17535(4).)

OS native encoding is now used for converting between Python strings and
Tcl objects.  This allows IDLE to work with emoji and other non-BMP
characters.  These characters can be displayed or copied and pasted to
or from the clipboard.  Converting strings from Tcl to Python and back
now never fails.  (Many people worked on this for eight years but the
problem was finally solved by Serhiy Storchaka in bpo-13153(5).)

New in 3.8.1:

Add option to toggle cursor blink off.  (Contributed by Zackery Spytz in
bpo-4603(6).)

Escape key now closes IDLE completion windows.  (Contributed by Johnny
Najera in bpo-38944(7).)

The changes above have been backported to 3.7 maintenance releases.

Add keywords to module name completion list.  (Contributed by Terry J.
Reedy in bpo-37765(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1529353

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5680

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37627

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17535

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13153

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4603

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38944

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37765


File: python.info,  Node: inspect<5>,  Next: io<3>,  Prev: IDLE and idlelib<4>,  Up: Improved Modules<6>

1.6.5.15 inspect
................

The *note inspect.getdoc(): a05. function can now find docstrings for
‘__slots__’ if that attribute is a *note dict: 256. where the values are
docstrings.  This provides documentation options similar to what we
already have for *note property(): 194, *note classmethod(): 166, and
*note staticmethod(): 419.:

     class AudioClip:
         __slots__ = {'bit_rate': 'expressed in kilohertz to one decimal place',
                      'duration': 'in seconds, rounded up to an integer'}
         def __init__(self, bit_rate, duration):
             self.bit_rate = round(bit_rate / 1000.0, 1)
             self.duration = ceil(duration)

(Contributed by Raymond Hettinger in bpo-36326(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36326


File: python.info,  Node: io<3>,  Next: itertools<4>,  Prev: inspect<5>,  Up: Improved Modules<6>

1.6.5.16 io
...........

In development mode (*note -X: 176. ‘env’) and in *note debug build:
1f9, the *note io.IOBase: 1f5. finalizer now logs the exception if the
‘close()’ method fails.  The exception is ignored silently by default in
release build.  (Contributed by Victor Stinner in bpo-18748(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18748


File: python.info,  Node: itertools<4>,  Next: json tool,  Prev: io<3>,  Up: Improved Modules<6>

1.6.5.17 itertools
..................

The *note itertools.accumulate(): a08. function added an option
'initial' keyword argument to specify an initial value:

     >>> from itertools import accumulate
     >>> list(accumulate([10, 5, 30, 15], initial=1000))
     [1000, 1010, 1015, 1045, 1060]

(Contributed by Lisa Roach in bpo-34659(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34659


File: python.info,  Node: json tool,  Next: logging<2>,  Prev: itertools<4>,  Up: Improved Modules<6>

1.6.5.18 json.tool
..................

Add option ‘--json-lines’ to parse every input line as a separate JSON
object.  (Contributed by Weipeng Hong in bpo-31553(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31553


File: python.info,  Node: logging<2>,  Next: math<5>,  Prev: json tool,  Up: Improved Modules<6>

1.6.5.19 logging
................

Added a 'force' keyword argument to *note logging.basicConfig(): a0b.
When set to true, any existing handlers attached to the root logger are
removed and closed before carrying out the configuration specified by
the other arguments.

This solves a long-standing problem.  Once a logger or 'basicConfig()'
had been called, subsequent calls to 'basicConfig()' were silently
ignored.  This made it difficult to update, experiment with, or teach
the various logging configuration options using the interactive prompt
or a Jupyter notebook.

(Suggested by Raymond Hettinger, implemented by Donghee Na, and reviewed
by Vinay Sajip in bpo-33897(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33897


File: python.info,  Node: math<5>,  Next: mmap<2>,  Prev: logging<2>,  Up: Improved Modules<6>

1.6.5.20 math
.............

Added new function *note math.dist(): a0d. for computing Euclidean
distance between two points.  (Contributed by Raymond Hettinger in
bpo-33089(1).)

Expanded the *note math.hypot(): a0e. function to handle multiple
dimensions.  Formerly, it only supported the 2-D case.  (Contributed by
Raymond Hettinger in bpo-33089(2).)

Added new function, *note math.prod(): a0f, as analogous function to
*note sum(): 46d. that returns the product of a ‘start’ value (default:
1) times an iterable of numbers:

     >>> prior = 0.8
     >>> likelihoods = [0.625, 0.84, 0.30]
     >>> math.prod(likelihoods, start=prior)
     0.126

(Contributed by Pablo Galindo in bpo-35606(3).)

Added two new combinatoric functions *note math.perm(): 6d4. and *note
math.comb(): 6d3.:

     >>> math.perm(10, 3)    # Permutations of 10 things taken 3 at a time
     720
     >>> math.comb(10, 3)    # Combinations of 10 things taken 3 at a time
     120

(Contributed by Yash Aggarwal, Keller Fuchs, Serhiy Storchaka, and
Raymond Hettinger in bpo-37128(4), bpo-37178(5), and bpo-35431(6).)

Added a new function *note math.isqrt(): a10. for computing accurate
integer square roots without conversion to floating point.  The new
function supports arbitrarily large integers.  It is faster than
‘floor(sqrt(n))’ but slower than *note math.sqrt(): a11.:

     >>> r = 650320427
     >>> s = r ** 2
     >>> isqrt(s - 1)         # correct
     650320426
     >>> floor(sqrt(s - 1))   # incorrect
     650320427

(Contributed by Mark Dickinson in bpo-36887(7).)

The function *note math.factorial(): 951. no longer accepts arguments
that are not int-like.  (Contributed by Pablo Galindo in bpo-33083(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33089

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33089

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35606

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37128

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37178

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35431

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36887

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33083


File: python.info,  Node: mmap<2>,  Next: multiprocessing<3>,  Prev: math<5>,  Up: Improved Modules<6>

1.6.5.21 mmap
.............

The *note mmap.mmap: 20b. class now has an *note madvise(): a13. method
to access the ‘madvise()’ system call.  (Contributed by Zackery Spytz in
bpo-32941(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32941


File: python.info,  Node: multiprocessing<3>,  Next: os<6>,  Prev: mmap<2>,  Up: Improved Modules<6>

1.6.5.22 multiprocessing
........................

Added new *note multiprocessing.shared_memory: 99. module.  (Contributed
by Davin Potts in bpo-35813(1).)

On macOS, the 'spawn' start method is now used by default.  (Contributed
by Victor Stinner in bpo-33725(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35813

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33725


File: python.info,  Node: os<6>,  Next: os path<5>,  Prev: multiprocessing<3>,  Up: Improved Modules<6>

1.6.5.23 os
...........

Added new function *note add_dll_directory(): 9f5. on Windows for
providing additional search paths for native dependencies when importing
extension modules or loading DLLs using *note ctypes: 2a.  (Contributed
by Steve Dower in bpo-36085(1).)

A new *note os.memfd_create(): a16. function was added to wrap the
‘memfd_create()’ syscall.  (Contributed by Zackery Spytz and Christian
Heimes in bpo-26836(2).)

On Windows, much of the manual logic for handling reparse points
(including symlinks and directory junctions) has been delegated to the
operating system.  Specifically, *note os.stat(): 4a3. will now traverse
anything supported by the operating system, while *note os.lstat(): 4a4.
will only open reparse points that identify as “name surrogates” while
others are opened as for ‘os.stat()’.  In all cases, *note
os.stat_result.st_mode: a17. will only have ‘S_IFLNK’ set for symbolic
links and not other kinds of reparse points.  To identify other kinds of
reparse point, check the new *note os.stat_result.st_reparse_tag: a18.
attribute.

On Windows, *note os.readlink(): 929. is now able to read directory
junctions.  Note that *note islink(): a19. will return ‘False’ for
directory junctions, and so code that checks ‘islink’ first will
continue to treat junctions as directories, while code that handles
errors from ‘os.readlink()’ may now treat junctions as links.

(Contributed by Steve Dower in bpo-37834(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36085

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26836

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37834


File: python.info,  Node: os path<5>,  Next: pathlib<7>,  Prev: os<6>,  Up: Improved Modules<6>

1.6.5.24 os.path
................

*note os.path: a2. functions that return a boolean result like *note
exists(): a1b, *note lexists(): a1c, *note isdir(): a1d, *note isfile():
a1e, *note islink(): a19, and *note ismount(): a1f. now return ‘False’
instead of raising *note ValueError: 202. or its subclasses *note
UnicodeEncodeError: 67a. and *note UnicodeDecodeError: a20. for paths
that contain characters or bytes unrepresentable at the OS level.
(Contributed by Serhiy Storchaka in bpo-33721(1).)

*note expanduser(): a21. on Windows now prefers the ‘USERPROFILE’
environment variable and does not use ‘HOME’, which is not normally set
for regular user accounts.  (Contributed by Anthony Sottile in
bpo-36264(2).)

*note isdir(): a1d. on Windows no longer returns ‘True’ for a link to a
non-existent directory.

*note realpath(): 225. on Windows now resolves reparse points, including
symlinks and directory junctions.

(Contributed by Steve Dower in bpo-37834(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33721

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36264

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37834


File: python.info,  Node: pathlib<7>,  Next: pickle,  Prev: os path<5>,  Up: Improved Modules<6>

1.6.5.25 pathlib
................

*note pathlib.Path: 229. methods that return a boolean result like *note
exists(): a23, *note is_dir(): 230, *note is_file(): 22f, *note
is_mount(): a24, *note is_symlink(): a25, *note is_block_device(): a26,
*note is_char_device(): a27, *note is_fifo(): a28, *note is_socket():
a29. now return ‘False’ instead of raising *note ValueError: 202. or its
subclass *note UnicodeEncodeError: 67a. for paths that contain
characters unrepresentable at the OS level.  (Contributed by Serhiy
Storchaka in bpo-33721(1).)

Added ‘pathlib.Path.link_to()’ which creates a hard link pointing to a
path.  (Contributed by Joannah Nanjekye in bpo-26978(2)) Note that
‘link_to’ was deprecated in 3.10 and removed in 3.12 in favor of a
‘hardlink_to’ method added in 3.10 which matches the semantics of the
existing ‘symlink_to’ method.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33721

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26978


File: python.info,  Node: pickle,  Next: plistlib,  Prev: pathlib<7>,  Up: Improved Modules<6>

1.6.5.26 pickle
...............

*note pickle: a6. extensions subclassing the C-optimized *note Pickler:
a2b. can now override the pickling logic of functions and classes by
defining the special *note reducer_override(): a2c. method.
(Contributed by Pierre Glaser and Olivier Grisel in bpo-35900(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35900


File: python.info,  Node: plistlib,  Next: pprint<3>,  Prev: pickle,  Up: Improved Modules<6>

1.6.5.27 plistlib
.................

Added new *note plistlib.UID: a2e. and enabled support for reading and
writing NSKeyedArchiver-encoded binary plists.  (Contributed by Jon
Janzen in bpo-26707(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26707


File: python.info,  Node: pprint<3>,  Next: py_compile<2>,  Prev: plistlib,  Up: Improved Modules<6>

1.6.5.28 pprint
...............

The *note pprint: ae. module added a 'sort_dicts' parameter to several
functions.  By default, those functions continue to sort dictionaries
before rendering or printing.  However, if 'sort_dicts' is set to false,
the dictionaries retain the order that keys were inserted.  This can be
useful for comparison to JSON inputs during debugging.

In addition, there is a convenience new function, *note pprint.pp():
a30. that is like *note pprint.pprint(): 82e. but with 'sort_dicts'
defaulting to ‘False’:

     >>> from pprint import pprint, pp
     >>> d = dict(source='input.txt', operation='filter', destination='output.txt')
     >>> pp(d, width=40)                  # Original order
     {'source': 'input.txt',
      'operation': 'filter',
      'destination': 'output.txt'}
     >>> pprint(d, width=40)              # Keys sorted alphabetically
     {'destination': 'output.txt',
      'operation': 'filter',
      'source': 'input.txt'}

(Contributed by Rémi Lapeyre in bpo-30670(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30670


File: python.info,  Node: py_compile<2>,  Next: shlex,  Prev: pprint<3>,  Up: Improved Modules<6>

1.6.5.29 py_compile
...................

*note py_compile.compile(): a32. now supports silent mode.  (Contributed
by Joannah Nanjekye in bpo-22640(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22640


File: python.info,  Node: shlex,  Next: shutil<4>,  Prev: py_compile<2>,  Up: Improved Modules<6>

1.6.5.30 shlex
..............

The new *note shlex.join(): a34. function acts as the inverse of *note
shlex.split(): 53f.  (Contributed by Bo Bayles in bpo-32102(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32102


File: python.info,  Node: shutil<4>,  Next: socket<4>,  Prev: shlex,  Up: Improved Modules<6>

1.6.5.31 shutil
...............

*note shutil.copytree(): a36. now accepts a new ‘dirs_exist_ok’ keyword
argument.  (Contributed by Josh Bronson in bpo-20849(1).)

*note shutil.make_archive(): 4b6. now defaults to the modern pax
(POSIX.1-2001) format for new archives to improve portability and
standards conformance, inherited from the corresponding change to the
*note tarfile: de. module.  (Contributed by C.A.M. Gerlach in
bpo-30661(2).)

*note shutil.rmtree(): 301. on Windows now removes directory junctions
without recursively removing their contents first.  (Contributed by
Steve Dower in bpo-37834(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20849

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30661

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37834


File: python.info,  Node: socket<4>,  Next: ssl<4>,  Prev: shutil<4>,  Up: Improved Modules<6>

1.6.5.32 socket
...............

Added *note create_server(): a38. and *note has_dualstack_ipv6(): a39.
convenience functions to automate the necessary tasks usually involved
when creating a server socket, including accepting both IPv4 and IPv6
connections on the same socket.  (Contributed by Giampaolo Rodolà in
bpo-17561(1).)

The *note socket.if_nameindex(): a3a, *note socket.if_nametoindex():
a3b, and *note socket.if_indextoname(): a3c. functions have been
implemented on Windows.  (Contributed by Zackery Spytz in bpo-37007(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17561

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37007


File: python.info,  Node: ssl<4>,  Next: statistics<4>,  Prev: socket<4>,  Up: Improved Modules<6>

1.6.5.33 ssl
............

Added *note post_handshake_auth: a3e. to enable and *note
verify_client_post_handshake(): a3f. to initiate TLS 1.3 post-handshake
authentication.  (Contributed by Christian Heimes in bpo-34670(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34670


File: python.info,  Node: statistics<4>,  Next: sys<7>,  Prev: ssl<4>,  Up: Improved Modules<6>

1.6.5.34 statistics
...................

Added *note statistics.fmean(): a41. as a faster, floating-point variant
of *note statistics.mean(): 6d5.  (Contributed by Raymond Hettinger and
Steven D’Aprano in bpo-35904(1).)

Added *note statistics.geometric_mean(): a42. (Contributed by Raymond
Hettinger in bpo-27181(2).)

Added *note statistics.multimode(): a43. that returns a list of the most
common values.  (Contributed by Raymond Hettinger in bpo-35892(3).)

Added *note statistics.quantiles(): a44. that divides data or a
distribution in to equiprobable intervals (e.g.  quartiles, deciles, or
percentiles).  (Contributed by Raymond Hettinger in bpo-36546(4).)

Added *note statistics.NormalDist: a45, a tool for creating and
manipulating normal distributions of a random variable.  (Contributed by
Raymond Hettinger in bpo-36018(5).)

     >>> temperature_feb = NormalDist.from_samples([4, 12, -3, 2, 7, 14])
     >>> temperature_feb.mean
     6.0
     >>> temperature_feb.stdev
     6.356099432828281

     >>> temperature_feb.cdf(3)            # Chance of being under 3 degrees
     0.3184678262814532
     >>> # Relative chance of being 7 degrees versus 10 degrees
     >>> temperature_feb.pdf(7) / temperature_feb.pdf(10)
     1.2039930378537762

     >>> el_niño = NormalDist(4, 2.5)
     >>> temperature_feb += el_niño        # Add in a climate effect
     >>> temperature_feb
     NormalDist(mu=10.0, sigma=6.830080526611674)

     >>> temperature_feb * (9/5) + 32      # Convert to Fahrenheit
     NormalDist(mu=50.0, sigma=12.294144947901014)
     >>> temperature_feb.samples(3)        # Generate random samples
     [7.672102882379219, 12.000027119750287, 4.647488369766392]

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35904

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27181

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35892

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36546

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36018


File: python.info,  Node: sys<7>,  Next: tarfile<5>,  Prev: statistics<4>,  Up: Improved Modules<6>

1.6.5.35 sys
............

Add new *note sys.unraisablehook(): 1f7. function which can be
overridden to control how “unraisable exceptions” are handled.  It is
called when an exception has occurred but there is no way for Python to
handle it.  For example, when a destructor raises an exception or during
garbage collection (*note gc.collect(): a47.).  (Contributed by Victor
Stinner in bpo-36829(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36829


File: python.info,  Node: tarfile<5>,  Next: threading<4>,  Prev: sys<7>,  Up: Improved Modules<6>

1.6.5.36 tarfile
................

The *note tarfile: de. module now defaults to the modern pax
(POSIX.1-2001) format for new archives, instead of the previous
GNU-specific one.  This improves cross-platform portability with a
consistent encoding (UTF-8) in a standardized and extensible format, and
offers several other benefits.  (Contributed by C.A.M. Gerlach in
bpo-36268(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36268


File: python.info,  Node: threading<4>,  Next: tokenize<2>,  Prev: tarfile<5>,  Up: Improved Modules<6>

1.6.5.37 threading
..................

Add a new *note threading.excepthook(): 851. function which handles
uncaught *note threading.Thread.run(): a4a. exception.  It can be
overridden to control how uncaught ‘threading.Thread.run()’ exceptions
are handled.  (Contributed by Victor Stinner in bpo-1230540(1).)

Add a new *note threading.get_native_id(): a4b. function and a *note
native_id: a4c. attribute to the *note threading.Thread: 956. class.
These return the native integral Thread ID of the current thread
assigned by the kernel.  This feature is only available on certain
platforms, see ‘get_native_id’ for more information.  (Contributed by
Jake Tesler in bpo-36084(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1230540

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36084


File: python.info,  Node: tokenize<2>,  Next: tkinter<4>,  Prev: threading<4>,  Up: Improved Modules<6>

1.6.5.38 tokenize
.................

The *note tokenize: fb. module now implicitly emits a ‘NEWLINE’ token
when provided with input that does not have a trailing new line.  This
behavior now matches what the C tokenizer does internally.  (Contributed
by Ammar Askar in bpo-33899(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33899


File: python.info,  Node: tkinter<4>,  Next: time<4>,  Prev: tokenize<2>,  Up: Improved Modules<6>

1.6.5.39 tkinter
................

Added methods ‘selection_from()’, ‘selection_present()’,
‘selection_range()’ and ‘selection_to()’ in the ‘tkinter.Spinbox’ class.
(Contributed by Juliette Monsel in bpo-34829(1).)

Added method ‘moveto()’ in the ‘tkinter.Canvas’ class.  (Contributed by
Juliette Monsel in bpo-23831(2).)

The ‘tkinter.PhotoImage’ class now has ‘transparency_get()’ and
‘transparency_set()’ methods.  (Contributed by Zackery Spytz in
bpo-25451(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34829

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23831

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25451


File: python.info,  Node: time<4>,  Next: typing<8>,  Prev: tkinter<4>,  Up: Improved Modules<6>

1.6.5.40 time
.............

Added new clock *note CLOCK_UPTIME_RAW: a50. for macOS 10.12.
(Contributed by Joannah Nanjekye in bpo-35702(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35702


File: python.info,  Node: typing<8>,  Next: unicodedata<5>,  Prev: time<4>,  Up: Improved Modules<6>

1.6.5.41 typing
...............

The *note typing: 104. module incorporates several new features:

   * A dictionary type with per-key types.  See PEP 589(1) and *note
     typing.TypedDict: 162.  TypedDict uses only string keys.  By
     default, every key is required to be present.  Specify
     “total=False” to allow keys to be optional:

          class Location(TypedDict, total=False):
              lat_long: tuple
              grid_square: str
              xy_coordinate: tuple

   * Literal types.  See PEP 586(2) and *note typing.Literal: 85b.
     Literal types indicate that a parameter or return value is
     constrained to one or more specific literal values:

          def get_status(port: int) -> Literal['connected', 'disconnected']:
              ...

   * “Final” variables, functions, methods and classes.  See PEP 591(3),
     *note typing.Final: 267. and *note typing.final(): 6b0.  The final
     qualifier instructs a static type checker to restrict subclassing,
     overriding, or reassignment:

          pi: Final[float] = 3.1415926536

   * Protocol definitions.  See PEP 544(4), *note typing.Protocol: 264.
     and *note typing.runtime_checkable(): 446.  Simple ABCs like *note
     typing.SupportsInt: a52. are now ‘Protocol’ subclasses.

   * New protocol class *note typing.SupportsIndex: a53.

   * New functions *note typing.get_origin(): 2ec. and *note
     typing.get_args(): 2ed.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0589/

   (2) https://peps.python.org/pep-0586/

   (3) https://peps.python.org/pep-0591/

   (4) https://peps.python.org/pep-0544/


File: python.info,  Node: unicodedata<5>,  Next: unittest<6>,  Prev: typing<8>,  Up: Improved Modules<6>

1.6.5.42 unicodedata
....................

The *note unicodedata: 105. module has been upgraded to use the Unicode
12.1.0(1) release.

New function *note is_normalized(): a55. can be used to verify a string
is in a specific normal form, often much faster than by actually
normalizing the string.  (Contributed by Max Belanger, David Euresti,
and Greg Price in bpo-32285(2) and bpo-37966(3)).

   ---------- Footnotes ----------

   (1) https://blog.unicode.org/2019/05/unicode-12-1-en.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32285

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37966


File: python.info,  Node: unittest<6>,  Next: venv<4>,  Prev: unicodedata<5>,  Up: Improved Modules<6>

1.6.5.43 unittest
.................

Added *note AsyncMock: a57. to support an asynchronous version of *note
Mock: a58.  Appropriate new assert functions for testing have been added
as well.  (Contributed by Lisa Roach in bpo-26467(1)).

Added *note addModuleCleanup(): a59. and *note addClassCleanup(): a5a.
to unittest to support cleanups for *note setUpModule(): a5b. and *note
setUpClass(): a5c.  (Contributed by Lisa Roach in bpo-24412(2).)

Several mock assert functions now also print a list of actual calls upon
failure.  (Contributed by Petter Strandmark in bpo-35047(3).)

*note unittest: 106. module gained support for coroutines to be used as
test cases with *note unittest.IsolatedAsyncioTestCase: 30c.
(Contributed by Andrew Svetlov in bpo-32972(4).)

Example:

     import unittest


     class TestRequest(unittest.IsolatedAsyncioTestCase):

         async def asyncSetUp(self):
             self.connection = await AsyncConnection()

         async def test_get(self):
             response = await self.connection.get("https://example.com")
             self.assertEqual(response.status_code, 200)

         async def asyncTearDown(self):
             await self.connection.close()


     if __name__ == "__main__":
         unittest.main()

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26467

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24412

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35047

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32972


File: python.info,  Node: venv<4>,  Next: weakref,  Prev: unittest<6>,  Up: Improved Modules<6>

1.6.5.44 venv
.............

*note venv: 111. now includes an ‘Activate.ps1’ script on all platforms
for activating virtual environments under PowerShell Core 6.1.
(Contributed by Brett Cannon in bpo-32718(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32718


File: python.info,  Node: weakref,  Next: xml<4>,  Prev: venv<4>,  Up: Improved Modules<6>

1.6.5.45 weakref
................

The proxy objects returned by *note weakref.proxy(): a5f. now support
the matrix multiplication operators ‘@’ and ‘@=’ in addition to the
other numeric operators.  (Contributed by Mark Dickinson in
bpo-36669(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36669


File: python.info,  Node: xml<4>,  Next: xmlrpc,  Prev: weakref,  Up: Improved Modules<6>

1.6.5.46 xml
............

As mitigation against DTD and external entity retrieval, the *note
xml.dom.minidom: 122. and *note xml.sax: 129. modules no longer process
external entities by default.  (Contributed by Christian Heimes in
bpo-17239(1).)

The ‘.find*()’ methods in the *note xml.etree.ElementTree: 125. module
support wildcard searches like ‘{*}tag’ which ignores the namespace and
‘{namespace}*’ which returns all tags in the given namespace.
(Contributed by Stefan Behnel in bpo-28238(2).)

The *note xml.etree.ElementTree: 125. module provides a new function
*note canonicalize(): a61. that implements C14N 2.0.  (Contributed by
Stefan Behnel in bpo-13611(3).)

The target object of *note xml.etree.ElementTree.XMLParser: a62. can
receive namespace declaration events through the new callback methods
‘start_ns()’ and ‘end_ns()’.  Additionally, the *note
xml.etree.ElementTree.TreeBuilder: a63. target can be configured to
process events about comments and processing instructions to include
them in the generated tree.  (Contributed by Stefan Behnel in
bpo-36676(4) and bpo-36673(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17239

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28238

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13611

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36676

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36673


File: python.info,  Node: xmlrpc,  Prev: xml<4>,  Up: Improved Modules<6>

1.6.5.47 xmlrpc
...............

*note xmlrpc.client.ServerProxy: a65. now supports an optional 'headers'
keyword argument for a sequence of HTTP headers to be sent with each
request.  Among other things, this makes it possible to upgrade from
default basic authentication to faster session authentication.
(Contributed by Cédric Krier in bpo-35153(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35153


File: python.info,  Node: Optimizations<6>,  Next: Build and C API Changes,  Prev: Improved Modules<6>,  Up: What’s New In Python 3 8

1.6.6 Optimizations
-------------------

   * The *note subprocess: d6. module can now use the *note
     os.posix_spawn(): 220. function in some cases for better
     performance.  Currently, it is only used on macOS and Linux (using
     glibc 2.24 or newer) if all these conditions are met:

        * 'close_fds' is false;

        * 'preexec_fn', 'pass_fds', 'cwd' and 'start_new_session'
          parameters are not set;

        * the 'executable' path contains a directory.

     (Contributed by Joannah Nanjekye and Victor Stinner in
     bpo-35537(1).)

   * *note shutil.copyfile(): a67, *note shutil.copy(): a68, *note
     shutil.copy2(): a69, *note shutil.copytree(): a36. and *note
     shutil.move(): a6a. use platform-specific “fast-copy” syscalls on
     Linux and macOS in order to copy the file more efficiently.
     “fast-copy” means that the copying operation occurs within the
     kernel, avoiding the use of userspace buffers in Python as in
     “‘outfd.write(infd.read())’”.  On Windows ‘shutil.copyfile()’ uses
     a bigger default buffer size (1 MiB instead of 16 KiB) and a *note
     memoryview(): 2eb.-based variant of *note shutil.copyfileobj():
     a6b. is used.  The speedup for copying a 512 MiB file within the
     same partition is about +26% on Linux, +50% on macOS and +40% on
     Windows.  Also, much less CPU cycles are consumed.  See *note
     Platform-dependent efficient copy operations: a6c. section.
     (Contributed by Giampaolo Rodolà in bpo-33671(2).)

   * *note shutil.copytree(): a36. uses *note os.scandir(): a6d.
     function and all copy functions depending from it use cached *note
     os.stat(): 4a3. values.  The speedup for copying a directory with
     8000 files is around +9% on Linux, +20% on Windows and +30% on a
     Windows SMB share.  Also the number of ‘os.stat()’ syscalls is
     reduced by 38% making ‘shutil.copytree()’ especially faster on
     network filesystems.  (Contributed by Giampaolo Rodolà in
     bpo-33695(3).)

   * The default protocol in the *note pickle: a6. module is now
     Protocol 4, first introduced in Python 3.4.  It offers better
     performance and smaller size compared to Protocol 3 available since
     Python 3.0.

   * Removed one *note Py_ssize_t: a6e. member from ‘PyGC_Head’.  All GC
     tracked objects (e.g.  tuple, list, dict) size is reduced 4 or 8
     bytes.  (Contributed by Inada Naoki in bpo-33597(4).)

   * *note uuid.UUID: a6f. now uses ‘__slots__’ to reduce its memory
     footprint.  (Contributed by Wouter Bolsterlee and Tal Einat in
     bpo-30977(5))

   * Improved performance of *note operator.itemgetter(): a70. by 33%.
     Optimized argument handling and added a fast path for the common
     case of a single non-negative integer index into a tuple (which is
     the typical use case in the standard library).  (Contributed by
     Raymond Hettinger in bpo-35664(6).)

   * Sped-up field lookups in *note collections.namedtuple(): 1ca.  They
     are now more than two times faster, making them the fastest form of
     instance variable lookup in Python.  (Contributed by Raymond
     Hettinger, Pablo Galindo, and Joe Jevnik, Serhiy Storchaka in
     bpo-32492(7).)

   * The *note list: 614. constructor does not overallocate the internal
     item buffer if the input iterable has a known length (the input
     implements ‘__len__’).  This makes the created list 12% smaller on
     average.  (Contributed by Raymond Hettinger and Pablo Galindo in
     bpo-33234(8).)

   * Doubled the speed of class variable writes.  When a non-dunder
     attribute was updated, there was an unnecessary call to update
     slots.  (Contributed by Stefan Behnel, Pablo Galindo Salgado,
     Raymond Hettinger, Neil Schemenauer, and Serhiy Storchaka in
     bpo-36012(9).)

   * Reduced an overhead of converting arguments passed to many builtin
     functions and methods.  This sped up calling some simple builtin
     functions and methods up to 20–50%.  (Contributed by Serhiy
     Storchaka in bpo-23867(10), bpo-35582(11) and bpo-36127(12).)

   * ‘LOAD_GLOBAL’ instruction now uses new “per opcode cache”
     mechanism.  It is about 40% faster now.  (Contributed by Yury
     Selivanov and Inada Naoki in bpo-26219(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35537

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33671

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33695

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33597

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30977

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35664

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32492

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33234

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36012

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23867

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35582

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36127

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26219


File: python.info,  Node: Build and C API Changes,  Next: Deprecated<8>,  Prev: Optimizations<6>,  Up: What’s New In Python 3 8

1.6.7 Build and C API Changes
-----------------------------

   * Default *note sys.abiflags: a72. became an empty string: the ‘m’
     flag for pymalloc became useless (builds with and without pymalloc
     are ABI compatible) and so has been removed.  (Contributed by
     Victor Stinner in bpo-36707(1).)

     Example of changes:

        * Only ‘python3.8’ program is installed, ‘python3.8m’ program is
          gone.

        * Only ‘python3.8-config’ script is installed,
          ‘python3.8m-config’ script is gone.

        * The ‘m’ flag has been removed from the suffix of dynamic
          library filenames: extension modules in the standard library
          as well as those produced and installed by third-party
          packages, like those downloaded from PyPI. On Linux, for
          example, the Python 3.7 suffix
          ‘.cpython-37m-x86_64-linux-gnu.so’ became
          ‘.cpython-38-x86_64-linux-gnu.so’ in Python 3.8.

   * The header files have been reorganized to better separate the
     different kinds of APIs:

        * ‘Include/*.h’ should be the portable public stable C API.

        * ‘Include/cpython/*.h’ should be the unstable C API specific to
          CPython; public API, with some private API prefixed by ‘_Py’
          or ‘_PY’.

        * ‘Include/internal/*.h’ is the private internal C API very
          specific to CPython.  This API comes with no backward
          compatibility warranty and should not be used outside CPython.
          It is only exposed for very specific needs like debuggers and
          profiles which has to access to CPython internals without
          calling functions.  This API is now installed by ‘make
          install’.

     (Contributed by Victor Stinner in bpo-35134(2) and bpo-35081(3),
     work initiated by Eric Snow in Python 3.7.)

   * Some macros have been converted to static inline functions:
     parameter types and return type are well defined, they don’t have
     issues specific to macros, variables have a local scopes.
     Examples:

        * *note Py_INCREF(): 571, *note Py_DECREF(): 572.

        * *note Py_XINCREF(): a73, *note Py_XDECREF(): 792.

        * ‘PyObject_INIT’, ‘PyObject_INIT_VAR’

        * Private functions: ‘_PyObject_GC_TRACK()’,
          ‘_PyObject_GC_UNTRACK()’, ‘_Py_Dealloc()’

     (Contributed by Victor Stinner in bpo-35059(4).)

   * The ‘PyByteArray_Init()’ and ‘PyByteArray_Fini()’ functions have
     been removed.  They did nothing since Python 2.7.4 and Python
     3.2.0, were excluded from the limited API (stable ABI), and were
     not documented.  (Contributed by Victor Stinner in bpo-35713(5).)

   * The result of *note PyExceptionClass_Name(): a74. is now of type
     ‘const char *’ rather of ‘char *’.  (Contributed by Serhiy
     Storchaka in bpo-33818(6).)

   * The duality of ‘Modules/Setup.dist’ and ‘Modules/Setup’ has been
     removed.  Previously, when updating the CPython source tree, one
     had to manually copy ‘Modules/Setup.dist’ (inside the source tree)
     to ‘Modules/Setup’ (inside the build tree) in order to reflect any
     changes upstream.  This was of a small benefit to packagers at the
     expense of a frequent annoyance to developers following CPython
     development, as forgetting to copy the file could produce build
     failures.

     Now the build system always reads from ‘Modules/Setup’ inside the
     source tree.  People who want to customize that file are encouraged
     to maintain their changes in a git fork of CPython or as patch
     files, as they would do for any other change to the source tree.

     (Contributed by Antoine Pitrou in bpo-32430(7).)

   * Functions that convert Python number to C integer like *note
     PyLong_AsLong(): 363. and argument parsing functions like *note
     PyArg_ParseTuple(): 574. with integer converting format units like
     ‘'i'’ will now use the *note __index__(): 720. special method
     instead of *note __int__(): 71f, if available.  The deprecation
     warning will be emitted for objects with the ‘__int__()’ method but
     without the ‘__index__()’ method (like *note Decimal: 29d. and
     *note Fraction: 1e7.).  *note PyNumber_Check(): a75. will now
     return ‘1’ for objects implementing ‘__index__()’.  *note
     PyNumber_Long(): a76, *note PyNumber_Float(): a77. and *note
     PyFloat_AsDouble(): a78. also now use the ‘__index__()’ method if
     available.  (Contributed by Serhiy Storchaka in bpo-36048(8) and
     bpo-20092(9).)

   * Heap-allocated type objects will now increase their reference count
     in *note PyObject_Init(): a79. (and its parallel macro
     ‘PyObject_INIT’) instead of in *note PyType_GenericAlloc(): a7a.
     Types that modify instance allocation or deallocation may need to
     be adjusted.  (Contributed by Eddie Elizondo in bpo-35810(10).)

   * The new function ‘PyCode_NewWithPosOnlyArgs()’ allows to create
     code objects like ‘PyCode_New()’, but with an extra
     'posonlyargcount' parameter for indicating the number of
     positional-only arguments.  (Contributed by Pablo Galindo in
     bpo-37221(11).)

   * ‘Py_SetPath()’ now sets *note sys.executable: 3bb. to the program
     full path (*note Py_GetProgramFullPath(): 3ba.) rather than to the
     program name (*note Py_GetProgramName(): 3bc.).  (Contributed by
     Victor Stinner in bpo-38234(12).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36707

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35059

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35713

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33818

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32430

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36048

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20092

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35810

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37221

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38234


File: python.info,  Node: Deprecated<8>,  Next: API and Feature Removals,  Prev: Build and C API Changes,  Up: What’s New In Python 3 8

1.6.8 Deprecated
----------------

   * The distutils ‘bdist_wininst’ command is now deprecated, use
     ‘bdist_wheel’ (wheel packages) instead.  (Contributed by Victor
     Stinner in bpo-37481(1).)

   * Deprecated methods ‘getchildren()’ and ‘getiterator()’ in the *note
     ElementTree: 125. module now emit a *note DeprecationWarning: 1a5.
     instead of *note PendingDeprecationWarning: 8d1.  They will be
     removed in Python 3.9.  (Contributed by Serhiy Storchaka in
     bpo-29209(2).)

   * Passing an object that is not an instance of *note
     concurrent.futures.ThreadPoolExecutor: 745. to *note
     loop.set_default_executor(): 746. is deprecated and will be
     prohibited in Python 3.9.  (Contributed by Elvis Pranskevichus in
     bpo-34075(3).)

   * The *note __getitem__(): 283. methods of *note
     xml.dom.pulldom.DOMEventStream: 738, *note
     wsgiref.util.FileWrapper: 739. and *note fileinput.FileInput: 73a.
     have been deprecated.

     Implementations of these methods have been ignoring their 'index'
     parameter, and returning the next item instead.  (Contributed by
     Berker Peksag in bpo-9372(4).)

   * The *note typing.NamedTuple: 2b0. class has deprecated the
     ‘_field_types’ attribute in favor of the ‘__annotations__’
     attribute which has the same information.  (Contributed by Raymond
     Hettinger in bpo-36320(5).)

   * *note ast: 8. classes ‘Num’, ‘Str’, ‘Bytes’, ‘NameConstant’ and
     ‘Ellipsis’ are considered deprecated and will be removed in future
     Python versions.  *note Constant: 2b9. should be used instead.
     (Contributed by Serhiy Storchaka in bpo-32892(6).)

   * *note ast.NodeVisitor: a7c. methods ‘visit_Num()’, ‘visit_Str()’,
     ‘visit_Bytes()’, ‘visit_NameConstant()’ and ‘visit_Ellipsis()’ are
     deprecated now and will not be called in future Python versions.
     Add the *note visit_Constant(): a7d. method to handle all constant
     nodes.  (Contributed by Serhiy Storchaka in bpo-36917(7).)

   * The ‘@asyncio.coroutine’ *note decorator: 734. is deprecated and
     will be removed in version 3.10.  Instead of ‘@asyncio.coroutine’,
     use *note async def: 5d4. instead.  (Contributed by Andrew Svetlov
     in bpo-36921(8).)

   * In *note asyncio: a, the explicit passing of a 'loop' argument has
     been deprecated and will be removed in version 3.10 for the
     following: *note asyncio.sleep(): a7e, *note asyncio.gather(): 600,
     *note asyncio.shield(): a7f, *note asyncio.wait_for(): 602, *note
     asyncio.wait(): 482, *note asyncio.as_completed(): 1aa, *note
     asyncio.Task: 1be, *note asyncio.Lock: a80, *note asyncio.Event:
     a81, *note asyncio.Condition: a82, *note asyncio.Semaphore: a83,
     *note asyncio.BoundedSemaphore: a84, *note asyncio.Queue: a85,
     *note asyncio.create_subprocess_exec(): a86, and *note
     asyncio.create_subprocess_shell(): a87.

   * The explicit passing of coroutine objects to *note asyncio.wait():
     482. has been deprecated and will be removed in version 3.11.
     (Contributed by Yury Selivanov in bpo-34790(9).)

   * The following functions and methods are deprecated in the *note
     gettext: 63. module: ‘lgettext()’, ‘ldgettext()’, ‘lngettext()’ and
     ‘ldngettext()’.  They return encoded bytes, and it’s possible that
     you will get unexpected Unicode-related exceptions if there are
     encoding problems with the translated strings.  It’s much better to
     use alternatives which return Unicode strings in Python 3.  These
     functions have been broken for a long time.

     Function ‘bind_textdomain_codeset()’, methods
     ‘NullTranslations.output_charset()’ and
     ‘NullTranslations.set_output_charset()’, and the 'codeset'
     parameter of functions *note translation(): a88. and *note
     install(): a89. are also deprecated, since they are only used for
     the ‘l*gettext()’ functions.  (Contributed by Serhiy Storchaka in
     bpo-33710(10).)

   * The ‘isAlive()’ method of *note threading.Thread: 956. has been
     deprecated.  (Contributed by Donghee Na in bpo-35283(11).)

   * Many builtin and extension functions that take integer arguments
     will now emit a deprecation warning for *note Decimal: 29d.s, *note
     Fraction: 1e7.s and any other objects that can be converted to
     integers only with a loss (e.g.  that have the *note __int__():
     71f. method but do not have the *note __index__(): 720. method).
     In future version they will be errors.  (Contributed by Serhiy
     Storchaka in bpo-36048(12).)

   * Deprecated passing the following arguments as keyword arguments:

        - 'func' in *note functools.partialmethod(): a8a, *note
          weakref.finalize(): a8b, *note profile.Profile.runcall(): a8c,
          ‘cProfile.Profile.runcall()’, *note bdb.Bdb.runcall(): a8d,
          *note trace.Trace.runfunc(): a8e. and *note curses.wrapper():
          a8f.

        - 'function' in *note unittest.TestCase.addCleanup(): a90.

        - 'fn' in the *note submit(): a91. method of *note
          concurrent.futures.ThreadPoolExecutor: 745. and *note
          concurrent.futures.ProcessPoolExecutor: 8f7.

        - 'callback' in *note contextlib.ExitStack.callback(): a92,
          ‘contextlib.AsyncExitStack.callback()’ and *note
          contextlib.AsyncExitStack.push_async_callback(): a93.

        - 'c' and 'typeid' in the ‘create()’ method of
          ‘multiprocessing.managers.Server’ and
          ‘multiprocessing.managers.SharedMemoryServer’.

        - 'obj' in *note weakref.finalize(): a8b.

     In future releases of Python, they will be *note positional-only:
     a94.  (Contributed by Serhiy Storchaka in bpo-36492(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37481

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29209

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34075

   (4) https://bugs.python.org/issue?@action=redirect&bpo=9372

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36320

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32892

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36917

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36921

   (9) https://bugs.python.org/issue?@action=redirect&bpo=34790

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33710

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35283

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36048

   (13) https://bugs.python.org/issue?@action=redirect&bpo=36492


File: python.info,  Node: API and Feature Removals,  Next: Porting to Python 3 8,  Prev: Deprecated<8>,  Up: What’s New In Python 3 8

1.6.9 API and Feature Removals
------------------------------

The following features and APIs have been removed from Python 3.8:

   * Starting with Python 3.3, importing ABCs from *note collections:
     1d. was deprecated, and importing should be done from *note
     collections.abc: 1e.  Being able to import from collections was
     marked for removal in 3.8, but has been delayed to 3.9.  (See
     gh-81134(1).)

   * The ‘macpath’ module, deprecated in Python 3.7, has been removed.
     (Contributed by Victor Stinner in bpo-35471(2).)

   * The function ‘platform.popen()’ has been removed, after having been
     deprecated since Python 3.3: use *note os.popen(): a96. instead.
     (Contributed by Victor Stinner in bpo-35345(3).)

   * The function ‘time.clock()’ has been removed, after having been
     deprecated since Python 3.3: use *note time.perf_counter(): a97. or
     *note time.process_time(): a98. instead, depending on your
     requirements, to have well-defined behavior.  (Contributed by
     Matthias Bussonnier in bpo-36895(4).)

   * The ‘pyvenv’ script has been removed in favor of ‘python3.8 -m
     venv’ to help eliminate confusion as to what Python interpreter the
     ‘pyvenv’ script is tied to.  (Contributed by Brett Cannon in
     bpo-25427(5).)

   * ‘parse_qs’, ‘parse_qsl’, and ‘escape’ are removed from the ‘cgi’
     module.  They are deprecated in Python 3.2 or older.  They should
     be imported from the ‘urllib.parse’ and ‘html’ modules instead.

   * ‘filemode’ function is removed from the *note tarfile: de. module.
     It is not documented and deprecated since Python 3.3.

   * The *note XMLParser: a62. constructor no longer accepts the 'html'
     argument.  It never had an effect and was deprecated in Python 3.4.
     All other parameters are now *note keyword-only: 2a5.  (Contributed
     by Serhiy Storchaka in bpo-29209(6).)

   * Removed the ‘doctype()’ method of *note XMLParser: a62.
     (Contributed by Serhiy Storchaka in bpo-29209(7).)

   * “unicode_internal” codec is removed.  (Contributed by Inada Naoki
     in bpo-36297(8).)

   * The ‘Cache’ and ‘Statement’ objects of the *note sqlite3: cf.
     module are not exposed to the user.  (Contributed by Aviv Palivoda
     in bpo-30262(9).)

   * The ‘bufsize’ keyword argument of *note fileinput.input(): 805. and
     *note fileinput.FileInput(): 73a. which was ignored and deprecated
     since Python 3.6 has been removed.  bpo-36952(10) (Contributed by
     Matthias Bussonnier.)

   * The functions ‘sys.set_coroutine_wrapper()’ and
     ‘sys.get_coroutine_wrapper()’ deprecated in Python 3.7 have been
     removed; bpo-36933(11) (Contributed by Matthias Bussonnier.)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/81134

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35471

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35345

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36895

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25427

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29209

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29209

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36297

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30262

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36952

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36933


File: python.info,  Node: Porting to Python 3 8,  Next: Notable changes in Python 3 8 1,  Prev: API and Feature Removals,  Up: What’s New In Python 3 8

1.6.10 Porting to Python 3.8
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in Python behavior::
* Changes in the Python API: Changes in the Python API<5>.
* Changes in the C API: Changes in the C API<4>.
* CPython bytecode changes: CPython bytecode changes<5>.
* Demos and Tools: Demos and Tools<2>.


File: python.info,  Node: Changes in Python behavior,  Next: Changes in the Python API<5>,  Up: Porting to Python 3 8

1.6.10.1 Changes in Python behavior
...................................

   * Yield expressions (both ‘yield’ and ‘yield from’ clauses) are now
     disallowed in comprehensions and generator expressions (aside from
     the iterable expression in the leftmost ‘for’ clause).
     (Contributed by Serhiy Storchaka in bpo-10544(1).)

   * The compiler now produces a *note SyntaxWarning: 469. when identity
     checks (‘is’ and ‘is not’) are used with certain types of literals
     (e.g.  strings, numbers).  These can often work by accident in
     CPython, but are not guaranteed by the language spec.  The warning
     advises users to use equality tests (‘==’ and ‘!=’) instead.
     (Contributed by Serhiy Storchaka in bpo-34850(2).)

   * The CPython interpreter can swallow exceptions in some
     circumstances.  In Python 3.8 this happens in fewer cases.  In
     particular, exceptions raised when getting the attribute from the
     type dictionary are no longer ignored.  (Contributed by Serhiy
     Storchaka in bpo-35459(3).)

   * Removed ‘__str__’ implementations from builtin types *note bool:
     46b, *note int: 257, *note float: 2f7, *note complex: 2f8. and few
     classes from the standard library.  They now inherit ‘__str__()’
     from *note object: a9b.  As result, defining the ‘__repr__()’
     method in the subclass of these classes will affect their string
     representation.  (Contributed by Serhiy Storchaka in bpo-36793(4).)

   * On AIX, *note sys.platform: a9c. doesn’t contain the major version
     anymore.  It is always ‘'aix'’, instead of ‘'aix3'’ ..  ‘'aix7'’.
     Since older Python versions include the version number, so it is
     recommended to always use ‘sys.platform.startswith('aix')’.
     (Contributed by M. Felt in bpo-36588(5).)

   * ‘PyEval_AcquireLock()’ and ‘PyEval_AcquireThread()’ now terminate
     the current thread if called while the interpreter is finalizing,
     making them consistent with *note PyEval_RestoreThread(): 3ac,
     *note Py_END_ALLOW_THREADS(): a9d, and *note PyGILState_Ensure():
     3ae.  If this behavior is not desired, guard the call by checking
     ‘_Py_IsFinalizing()’ or *note sys.is_finalizing(): a9e.
     (Contributed by Joannah Nanjekye in bpo-36475(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10544

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34850

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35459

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36793

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36588

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36475


File: python.info,  Node: Changes in the Python API<5>,  Next: Changes in the C API<4>,  Prev: Changes in Python behavior,  Up: Porting to Python 3 8

1.6.10.2 Changes in the Python API
..................................

   * The *note os.getcwdb(): aa0. function now uses the UTF-8 encoding
     on Windows, rather than the ANSI code page: see PEP 529(1) for the
     rationale.  The function is no longer deprecated on Windows.
     (Contributed by Victor Stinner in bpo-37412(2).)

   * *note subprocess.Popen: 199. can now use *note os.posix_spawn():
     220. in some cases for better performance.  On Windows Subsystem
     for Linux and QEMU User Emulation, the ‘Popen’ constructor using
     ‘os.posix_spawn()’ no longer raises an exception on errors like
     “missing program”.  Instead the child process fails with a non-zero
     *note returncode: aa1.  (Contributed by Joannah Nanjekye and Victor
     Stinner in bpo-35537(3).)

   * The 'preexec_fn' argument of * *note subprocess.Popen: 199. is no
     longer compatible with subinterpreters.  The use of the parameter
     in a subinterpreter now raises *note RuntimeError: 195.
     (Contributed by Eric Snow in bpo-34651(4), modified by Christian
     Heimes in bpo-37951(5).)

   * The *note imaplib.IMAP4.logout(): aa2. method no longer silently
     ignores arbitrary exceptions.  (Contributed by Victor Stinner in
     bpo-36348(6).)

   * The function ‘platform.popen()’ has been removed, after having been
     deprecated since Python 3.3: use *note os.popen(): a96. instead.
     (Contributed by Victor Stinner in bpo-35345(7).)

   * The *note statistics.mode(): aa3. function no longer raises an
     exception when given multimodal data.  Instead, it returns the
     first mode encountered in the input data.  (Contributed by Raymond
     Hettinger in bpo-35892(8).)

   * The *note selection(): aa4. method of the *note
     tkinter.ttk.Treeview: aa5. class no longer takes arguments.  Using
     it with arguments for changing the selection was deprecated in
     Python 3.6.  Use specialized methods like *note selection_set():
     aa6. for changing the selection.  (Contributed by Serhiy Storchaka
     in bpo-31508(9).)

   * The *note writexml(): aa7, *note toxml(): aa8. and *note
     toprettyxml(): aa9. methods of *note xml.dom.minidom: 122. and the
     *note write(): aaa. method of *note xml.etree.ElementTree: 125. now
     preserve the attribute order specified by the user.  (Contributed
     by Diego Rojas and Raymond Hettinger in bpo-34160(10).)

   * A *note dbm.dumb: 32. database opened with flags ‘'r'’ is now
     read-only.  *note dbm.dumb.open(): aab. with flags ‘'r'’ and ‘'w'’
     no longer creates a database if it does not exist.  (Contributed by
     Serhiy Storchaka in bpo-32749(11).)

   * The ‘doctype()’ method defined in a subclass of *note XMLParser:
     a62. will no longer be called and will emit a *note RuntimeWarning:
     1bd. instead of a *note DeprecationWarning: 1a5.  Define the *note
     doctype(): aac. method on a target for handling an XML doctype
     declaration.  (Contributed by Serhiy Storchaka in bpo-29209(12).)

   * A *note RuntimeError: 195. is now raised when the custom metaclass
     doesn’t provide the ‘__classcell__’ entry in the namespace passed
     to ‘type.__new__’.  A *note DeprecationWarning: 1a5. was emitted in
     Python 3.6–3.7.  (Contributed by Serhiy Storchaka in
     bpo-23722(13).)

   * The *note cProfile.Profile: 9ee. class can now be used as a context
     manager.  (Contributed by Scott Sanderson in bpo-29235(14).)

   * *note shutil.copyfile(): a67, *note shutil.copy(): a68, *note
     shutil.copy2(): a69, *note shutil.copytree(): a36. and *note
     shutil.move(): a6a. use platform-specific “fast-copy” syscalls (see
     *note Platform-dependent efficient copy operations: a6c. section).

   * *note shutil.copyfile(): a67. default buffer size on Windows was
     changed from 16 KiB to 1 MiB.

   * The ‘PyGC_Head’ struct has changed completely.  All code that
     touched the struct member should be rewritten.  (See
     bpo-33597(15).)

   * The *note PyInterpreterState: 8c5. struct has been moved into the
     “internal” header files (specifically
     Include/internal/pycore_pystate.h).  An opaque ‘PyInterpreterState’
     is still available as part of the public API (and stable ABI). The
     docs indicate that none of the struct’s fields are public, so we
     hope no one has been using them.  However, if you do rely on one or
     more of those private fields and have no alternative then please
     open a BPO issue.  We’ll work on helping you adjust (possibly
     including adding accessor functions to the public API). (See
     bpo-35886(16).)

   * The *note mmap.flush(): aad. method now returns ‘None’ on success
     and raises an exception on error under all platforms.  Previously,
     its behavior was platform-dependent: a nonzero value was returned
     on success; zero was returned on error under Windows.  A zero value
     was returned on success; an exception was raised on error under
     Unix.  (Contributed by Berker Peksag in bpo-2122(17).)

   * *note xml.dom.minidom: 122. and *note xml.sax: 129. modules no
     longer process external entities by default.  (Contributed by
     Christian Heimes in bpo-17239(18).)

   * Deleting a key from a read-only *note dbm: 31. database (*note
     dbm.dumb: 32, *note dbm.gnu: 33. or *note dbm.ndbm: 34.) raises
     ‘error’ (*note dbm.dumb.error: aae, *note dbm.gnu.error: aaf. or
     *note dbm.ndbm.error: ab0.) instead of *note KeyError: 345.
     (Contributed by Xiang Zhang in bpo-33106(19).)

   * Simplified AST for literals.  All constants will be represented as
     *note ast.Constant: 2b9. instances.  Instantiating old classes
     ‘Num’, ‘Str’, ‘Bytes’, ‘NameConstant’ and ‘Ellipsis’ will return an
     instance of ‘Constant’.  (Contributed by Serhiy Storchaka in
     bpo-32892(20).)

   * *note expanduser(): a21. on Windows now prefers the ‘USERPROFILE’
     environment variable and does not use ‘HOME’, which is not normally
     set for regular user accounts.  (Contributed by Anthony Sottile in
     bpo-36264(21).)

   * The exception *note asyncio.CancelledError: 1b8. now inherits from
     *note BaseException: 5be. rather than *note Exception: 9e5. and no
     longer inherits from *note concurrent.futures.CancelledError: 9e6.
     (Contributed by Yury Selivanov in bpo-32528(22).)

   * The function *note asyncio.wait_for(): 602. now correctly waits for
     cancellation when using an instance of *note asyncio.Task: 1be.
     Previously, upon reaching 'timeout', it was cancelled and
     immediately returned.  (Contributed by Elvis Pranskevichus in
     bpo-32751(23).)

   * The function *note asyncio.BaseTransport.get_extra_info(): ab1. now
     returns a safe to use socket object when ‘socket’ is passed to the
     'name' parameter.  (Contributed by Yury Selivanov in
     bpo-37027(24).)

   * *note asyncio.BufferedProtocol: ab2. has graduated to the stable
     API.

   * DLL dependencies for extension modules and DLLs loaded with *note
     ctypes: 2a. on Windows are now resolved more securely.  Only the
     system paths, the directory containing the DLL or PYD file, and
     directories added with *note add_dll_directory(): 9f5. are searched
     for load-time dependencies.  Specifically, ‘PATH’ and the current
     working directory are no longer used, and modifications to these
     will no longer have any effect on normal DLL resolution.  If your
     application relies on these mechanisms, you should check for
     ‘add_dll_directory()’ and if it exists, use it to add your DLLs
     directory while loading your library.  Note that Windows 7 users
     will need to ensure that Windows Update KB2533623 has been
     installed (this is also verified by the installer).  (Contributed
     by Steve Dower in bpo-36085(25).)

   * The header files and functions related to pgen have been removed
     after its replacement by a pure Python implementation.
     (Contributed by Pablo Galindo in bpo-36623(26).)

   * *note types.CodeType: 2df. has a new parameter in the second
     position of the constructor ('posonlyargcount') to support
     positional-only arguments defined in PEP 570(27).  The first
     argument ('argcount') now represents the total number of positional
     arguments (including positional-only arguments).  The new
     ‘replace()’ method of ‘types.CodeType’ can be used to make the code
     future-proof.

   * The parameter ‘digestmod’ for *note hmac.new(): ab4. no longer uses
     the MD5 digest by default.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0529/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37412

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35537

   (4) https://bugs.python.org/issue?@action=redirect&bpo=34651

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37951

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36348

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35345

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35892

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31508

   (10) https://bugs.python.org/issue?@action=redirect&bpo=34160

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32749

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29209

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29235

   (15) https://bugs.python.org/issue?@action=redirect&bpo=33597

   (16) https://bugs.python.org/issue?@action=redirect&bpo=35886

   (17) https://bugs.python.org/issue?@action=redirect&bpo=2122

   (18) https://bugs.python.org/issue?@action=redirect&bpo=17239

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33106

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32892

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36264

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32528

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32751

   (24) https://bugs.python.org/issue?@action=redirect&bpo=37027

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36085

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36623

   (27) https://peps.python.org/pep-0570/


File: python.info,  Node: Changes in the C API<4>,  Next: CPython bytecode changes<5>,  Prev: Changes in the Python API<5>,  Up: Porting to Python 3 8

1.6.10.3 Changes in the C API
.............................

   * The *note PyCompilerFlags: ab6. structure got a new
     'cf_feature_version' field.  It should be initialized to
     ‘PY_MINOR_VERSION’.  The field is ignored by default, and is used
     if and only if ‘PyCF_ONLY_AST’ flag is set in 'cf_flags'.
     (Contributed by Guido van Rossum in bpo-35766(1).)

   * The ‘PyEval_ReInitThreads()’ function has been removed from the C
     API. It should not be called explicitly: use *note
     PyOS_AfterFork_Child(): 3fe. instead.  (Contributed by Victor
     Stinner in bpo-36728(2).)

   * On Unix, C extensions are no longer linked to libpython except on
     Android and Cygwin.  When Python is embedded, ‘libpython’ must not
     be loaded with ‘RTLD_LOCAL’, but ‘RTLD_GLOBAL’ instead.
     Previously, using ‘RTLD_LOCAL’, it was already not possible to load
     C extensions which were not linked to ‘libpython’, like C
     extensions of the standard library built by the ‘*shared*’ section
     of ‘Modules/Setup’.  (Contributed by Victor Stinner in
     bpo-21536(3).)

   * Use of ‘#’ variants of formats in parsing or building value (e.g.
     *note PyArg_ParseTuple(): 574, *note Py_BuildValue(): 8af, *note
     PyObject_CallFunction(): 3a1, etc.)  without ‘PY_SSIZE_T_CLEAN’
     defined raises ‘DeprecationWarning’ now.  It will be removed in
     3.10 or 4.0.  Read *note Parsing arguments and building values:
     8b0. for detail.  (Contributed by Inada Naoki in bpo-36381(4).)

   * Instances of heap-allocated types (such as those created with *note
     PyType_FromSpec(): 580.) hold a reference to their type object.
     Increasing the reference count of these type objects has been moved
     from *note PyType_GenericAlloc(): a7a. to the more low-level
     functions, *note PyObject_Init(): a79. and ‘PyObject_INIT’.  This
     makes types created through ‘PyType_FromSpec()’ behave like other
     classes in managed code.

     *note Statically allocated types: 782. are not affected.

     For the vast majority of cases, there should be no side effect.
     However, types that manually increase the reference count after
     allocating an instance (perhaps to work around the bug) may now
     become immortal.  To avoid this, these classes need to call
     Py_DECREF on the type object during instance deallocation.

     To correctly port these types into 3.8, please apply the following
     changes:

        * Remove *note Py_INCREF: 571. on the type object after
          allocating an instance - if any.  This may happen after
          calling *note PyObject_New: 98f, *note PyObject_NewVar: 990,
          *note PyObject_GC_New(): ab7, *note PyObject_GC_NewVar(): ab8,
          or any other custom allocator that uses *note PyObject_Init():
          a79. or ‘PyObject_INIT’.

          Example:

               static foo_struct *
               foo_new(PyObject *type) {
                   foo_struct *foo = PyObject_GC_New(foo_struct, (PyTypeObject *) type);
                   if (foo == NULL)
                       return NULL;
               #if PY_VERSION_HEX < 0x03080000
                   // Workaround for Python issue 35810; no longer necessary in Python 3.8
                   PY_INCREF(type)
               #endif
                   return foo;
               }

        * Ensure that all custom ‘tp_dealloc’ functions of
          heap-allocated types decrease the type’s reference count.

          Example:

               static void
               foo_dealloc(foo_struct *instance) {
                   PyObject *type = Py_TYPE(instance);
                   PyObject_GC_Del(instance);
               #if PY_VERSION_HEX >= 0x03080000
                   // This was not needed before Python 3.8 (Python issue 35810)
                   Py_DECREF(type);
               #endif
               }

     (Contributed by Eddie Elizondo in bpo-35810(5).)

   * The *note Py_DEPRECATED(): ab9. macro has been implemented for
     MSVC.  The macro now must be placed before the symbol name.

     Example:

          Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);

     (Contributed by Zackery Spytz in bpo-33407(6).)

   * The interpreter does not pretend to support binary compatibility of
     extension types across feature releases, anymore.  A *note
     PyTypeObject: aba. exported by a third-party extension module is
     supposed to have all the slots expected in the current Python
     version, including *note tp_finalize: abb. (*note
     Py_TPFLAGS_HAVE_FINALIZE: 3f5. is not checked anymore before
     reading ‘tp_finalize’).

     (Contributed by Antoine Pitrou in bpo-32388(7).)

   * The functions ‘PyNode_AddChild()’ and ‘PyParser_AddToken()’ now
     accept two additional ‘int’ arguments 'end_lineno' and
     'end_col_offset'.

   * The ‘libpython38.a’ file to allow MinGW tools to link directly
     against ‘python38.dll’ is no longer included in the regular Windows
     distribution.  If you require this file, it may be generated with
     the ‘gendef’ and ‘dlltool’ tools, which are part of the MinGW
     binutils package:

          gendef - python38.dll > tmp.def
          dlltool --dllname python38.dll --def tmp.def --output-lib libpython38.a

     The location of an installed ‘pythonXY.dll’ will depend on the
     installation options and the version and language of Windows.  See
     *note Using Python on Windows: abc. for more information.  The
     resulting library should be placed in the same directory as
     ‘pythonXY.lib’, which is generally the ‘libs’ directory under your
     Python installation.

     (Contributed by Steve Dower in bpo-37351(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35766

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36728

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21536

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36381

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35810

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33407

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32388

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37351


File: python.info,  Node: CPython bytecode changes<5>,  Next: Demos and Tools<2>,  Prev: Changes in the C API<4>,  Up: Porting to Python 3 8

1.6.10.4 CPython bytecode changes
.................................

   * The interpreter loop has been simplified by moving the logic of
     unrolling the stack of blocks into the compiler.  The compiler
     emits now explicit instructions for adjusting the stack of values
     and calling the cleaning-up code for *note break: abe, *note
     continue: 9d4. and *note return: 9d9.

     Removed opcodes ‘BREAK_LOOP’, ‘CONTINUE_LOOP’, ‘SETUP_LOOP’ and
     ‘SETUP_EXCEPT’.  Added new opcodes ‘ROT_FOUR’, ‘BEGIN_FINALLY’,
     ‘CALL_FINALLY’ and ‘POP_FINALLY’.  Changed the behavior of
     ‘END_FINALLY’ and ‘WITH_CLEANUP_START’.

     (Contributed by Mark Shannon, Antoine Pitrou and Serhiy Storchaka
     in bpo-17611(1).)

   * Added new opcode *note END_ASYNC_FOR: abf. for handling exceptions
     raised when awaiting a next item in an *note async for: ac0. loop.
     (Contributed by Serhiy Storchaka in bpo-33041(2).)

   * The *note MAP_ADD: ac1. now expects the value as the first element
     in the stack and the key as the second element.  This change was
     made so the key is always evaluated before the value in dictionary
     comprehensions, as proposed by PEP 572(3).  (Contributed by Jörn
     Heissler in bpo-35224(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17611

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33041

   (3) https://peps.python.org/pep-0572/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35224


File: python.info,  Node: Demos and Tools<2>,  Prev: CPython bytecode changes<5>,  Up: Porting to Python 3 8

1.6.10.5 Demos and Tools
........................

Added a benchmark script for timing various ways to access variables:
‘Tools/scripts/var_access_benchmark.py’.  (Contributed by Raymond
Hettinger in bpo-35884(1).)

Here’s a summary of performance improvements since Python 3.3:

     Python version                       3.3     3.4     3.5     3.6     3.7     3.8
     --------------                       ---     ---     ---     ---     ---     ---

     Variable and attribute read access:
         read_local                       4.0     7.1     7.1     5.4     5.1     3.9
         read_nonlocal                    5.3     7.1     8.1     5.8     5.4     4.4
         read_global                     13.3    15.5    19.0    14.3    13.6     7.6
         read_builtin                    20.0    21.1    21.6    18.5    19.0     7.5
         read_classvar_from_class        20.5    25.6    26.5    20.7    19.5    18.4
         read_classvar_from_instance     18.5    22.8    23.5    18.8    17.1    16.4
         read_instancevar                26.8    32.4    33.1    28.0    26.3    25.4
         read_instancevar_slots          23.7    27.8    31.3    20.8    20.8    20.2
         read_namedtuple                 68.5    73.8    57.5    45.0    46.8    18.4
         read_boundmethod                29.8    37.6    37.9    29.6    26.9    27.7

     Variable and attribute write access:
         write_local                      4.6     8.7     9.3     5.5     5.3     4.3
         write_nonlocal                   7.3    10.5    11.1     5.6     5.5     4.7
         write_global                    15.9    19.7    21.2    18.0    18.0    15.8
         write_classvar                  81.9    92.9    96.0   104.6   102.1    39.2
         write_instancevar               36.4    44.6    45.8    40.0    38.9    35.5
         write_instancevar_slots         28.7    35.6    36.1    27.3    26.6    25.7

     Data structure read access:
         read_list                       19.2    24.2    24.5    20.8    20.8    19.0
         read_deque                      19.9    24.7    25.5    20.2    20.6    19.8
         read_dict                       19.7    24.3    25.7    22.3    23.0    21.0
         read_strdict                    17.9    22.6    24.3    19.5    21.2    18.9

     Data structure write access:
         write_list                      21.2    27.1    28.5    22.5    21.6    20.0
         write_deque                     23.8    28.7    30.1    22.7    21.8    23.5
         write_dict                      25.9    31.4    33.3    29.3    29.2    24.7
         write_strdict                   22.9    28.4    29.9    27.5    25.2    23.1

     Stack (or queue) operations:
         list_append_pop                144.2    93.4   112.7    75.4    74.2    50.8
         deque_append_pop                30.4    43.5    57.0    49.4    49.2    42.5
         deque_append_popleft            30.8    43.7    57.3    49.7    49.7    42.8

     Timing loop:
         loop_overhead                    0.3     0.5     0.6     0.4     0.3     0.3

The benchmarks were measured on an Intel® Core™ i7-4960HQ processor(2)
running the macOS 64-bit builds found at python.org(3).  The benchmark
script displays timings in nanoseconds.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35884

   (2) 
https://ark.intel.com/content/www/us/en/ark/products/76088/intel-core-i7-4960hq-processor-6m-cache-up-to-3-80-ghz.html

   (3) https://www.python.org/downloads/macos/


File: python.info,  Node: Notable changes in Python 3 8 1,  Next: Notable changes in Python 3 8 2,  Prev: Porting to Python 3 8,  Up: What’s New In Python 3 8

1.6.11 Notable changes in Python 3.8.1
--------------------------------------

Due to significant security concerns, the 'reuse_address' parameter of
*note asyncio.loop.create_datagram_endpoint(): 736. is no longer
supported.  This is because of the behavior of the socket option
‘SO_REUSEADDR’ in UDP. For more details, see the documentation for
‘loop.create_datagram_endpoint()’.  (Contributed by Kyle Stanley,
Antoine Pitrou, and Yury Selivanov in bpo-37228(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37228


File: python.info,  Node: Notable changes in Python 3 8 2,  Next: Notable changes in Python 3 8 3,  Prev: Notable changes in Python 3 8 1,  Up: What’s New In Python 3 8

1.6.12 Notable changes in Python 3.8.2
--------------------------------------

Fixed a regression with the ‘ignore’ callback of *note
shutil.copytree(): a36.  The argument types are now str and List[str]
again.  (Contributed by Manuel Barkhau and Giampaolo Rodola in
gh-83571(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/83571


File: python.info,  Node: Notable changes in Python 3 8 3,  Next: Notable changes in Python 3 8 8,  Prev: Notable changes in Python 3 8 2,  Up: What’s New In Python 3 8

1.6.13 Notable changes in Python 3.8.3
--------------------------------------

The constant values of future flags in the *note __future__: 0. module
are updated in order to prevent collision with compiler flags.
Previously ‘PyCF_ALLOW_TOP_LEVEL_AWAIT’ was clashing with
‘CO_FUTURE_DIVISION’.  (Contributed by Batuhan Taskaya in gh-83743(1))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/83743


File: python.info,  Node: Notable changes in Python 3 8 8,  Next: Notable changes in Python 3 8 9,  Prev: Notable changes in Python 3 8 3,  Up: What’s New In Python 3 8

1.6.14 Notable changes in Python 3.8.8
--------------------------------------

Earlier Python versions allowed using both ‘;’ and ‘&’ as query
parameter separators in *note urllib.parse.parse_qs(): 27a. and *note
urllib.parse.parse_qsl(): 279.  Due to security concerns, and to conform
with newer W3C recommendations, this has been changed to allow only a
single separator key, with ‘&’ as the default.  This change also affects
‘cgi.parse()’ and ‘cgi.parse_multipart()’ as they use the affected
functions internally.  For more details, please see their respective
documentation.  (Contributed by Adam Goldschmidt, Senthil Kumaran and
Ken Jin in bpo-42967(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967


File: python.info,  Node: Notable changes in Python 3 8 9,  Next: Notable changes in Python 3 8 10,  Prev: Notable changes in Python 3 8 8,  Up: What’s New In Python 3 8

1.6.15 Notable changes in Python 3.8.9
--------------------------------------

A security fix alters the *note ftplib.FTP: 903. behavior to not trust
the IPv4 address sent from the remote server when setting up a passive
data channel.  We reuse the ftp server IP address instead.  For unusual
code requiring the old behavior, set a ‘trust_server_pasv_ipv4_address’
attribute on your FTP instance to ‘True’.  (See gh-87451(1))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87451


File: python.info,  Node: Notable changes in Python 3 8 10,  Next: Notable changes in Python 3 8 10<2>,  Prev: Notable changes in Python 3 8 9,  Up: What’s New In Python 3 8

1.6.16 Notable changes in Python 3.8.10
---------------------------------------

* Menu:

* macOS 11.0 (Big Sur) and Apple Silicon Mac support: macOS 11 0 Big Sur and Apple Silicon Mac support<2>.


File: python.info,  Node: macOS 11 0 Big Sur and Apple Silicon Mac support<2>,  Up: Notable changes in Python 3 8 10

1.6.16.1 macOS 11.0 (Big Sur) and Apple Silicon Mac support
...........................................................

As of 3.8.10, Python now supports building and running on macOS 11 (Big
Sur) and on Apple Silicon Macs (based on the ‘ARM64’ architecture).  A
new universal build variant, ‘universal2’, is now available to natively
support both ‘ARM64’ and ‘Intel 64’ in one set of executables.  Note
that support for “weaklinking”, building binaries targeted for newer
versions of macOS that will also run correctly on older versions by
testing at runtime for missing features, is not included in this
backport from Python 3.9; to support a range of macOS versions, continue
to target for and build on the oldest version in the range.

(Originally contributed by Ronald Oussoren and Lawrence D’Anna in
gh-85272(1), with fixes by FX Coudert and Eli Rykoff, and backported to
3.8 by Maxime Bélanger and Ned Deily)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/85272


File: python.info,  Node: Notable changes in Python 3 8 10<2>,  Next: Notable changes in Python 3 8 12,  Prev: Notable changes in Python 3 8 10,  Up: What’s New In Python 3 8

1.6.17 Notable changes in Python 3.8.10
---------------------------------------

* Menu:

* urllib.parse: urllib parse<4>.


File: python.info,  Node: urllib parse<4>,  Up: Notable changes in Python 3 8 10<2>

1.6.17.1 urllib.parse
.....................

The presence of newline or tab characters in parts of a URL allows for
some forms of attacks.  Following the WHATWG specification that updates
RFC 3986(1), ASCII newline ‘\n’, ‘\r’ and tab ‘\t’ characters are
stripped from the URL by the parser in *note urllib.parse: 10a.
preventing such attacks.  The removal characters are controlled by a new
module level variable ‘urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE’.  (See
bpo-43882(2))

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3986.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43882


File: python.info,  Node: Notable changes in Python 3 8 12,  Next: Notable security feature in 3 8 14,  Prev: Notable changes in Python 3 8 10<2>,  Up: What’s New In Python 3 8

1.6.18 Notable changes in Python 3.8.12
---------------------------------------

* Menu:

* Changes in the Python API: Changes in the Python API<6>.


File: python.info,  Node: Changes in the Python API<6>,  Up: Notable changes in Python 3 8 12

1.6.18.1 Changes in the Python API
..................................

Starting with Python 3.8.12 the *note ipaddress: 80. module no longer
accepts any leading zeros in IPv4 address strings.  Leading zeros are
ambiguous and interpreted as octal notation by some libraries.  For
example the legacy function *note socket.inet_aton(): 96b. treats
leading zeros as octal notation.  glibc implementation of modern *note
inet_pton(): 96c. does not accept any leading zeros.

(Originally contributed by Christian Heimes in bpo-36384(1), and
backported to 3.8 by Achraf Merzouki.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36384


File: python.info,  Node: Notable security feature in 3 8 14,  Next: Notable changes in 3 8 17,  Prev: Notable changes in Python 3 8 12,  Up: What’s New In Python 3 8

1.6.19 Notable security feature in 3.8.14
-----------------------------------------

Converting between *note int: 257. and *note str: 44f. in bases other
than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10
(decimal) now raises a *note ValueError: 202. if the number of digits in
string form is above a limit to avoid potential denial of service
attacks due to the algorithmic complexity.  This is a mitigation for CVE
2020-10735(1).  This limit can be configured or disabled by environment
variable, command line flag, or *note sys: d9. APIs.  See the *note
integer string conversion length limitation: 5f8. documentation.  The
default limit is 4300 digits in string form.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: Notable changes in 3 8 17,  Prev: Notable security feature in 3 8 14,  Up: What’s New In Python 3 8

1.6.20 Notable changes in 3.8.17
--------------------------------

* Menu:

* tarfile: tarfile<6>.


File: python.info,  Node: tarfile<6>,  Up: Notable changes in 3 8 17

1.6.20.1 tarfile
................

   * The extraction methods in *note tarfile: de, and *note
     shutil.unpack_archive(): 46e, have a new a 'filter' argument that
     allows limiting tar features than may be surprising or dangerous,
     such as creating files outside the destination directory.  See
     *note Extraction filters: 46f. for details.  In Python 3.12, use
     without the 'filter' argument will show a *note DeprecationWarning:
     1a5.  In Python 3.14, the default will switch to ‘'data'’.
     (Contributed by Petr Viktorin in PEP 706(1).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0706/


File: python.info,  Node: What’s New In Python 3 7,  Next: What’s New In Python 3 6,  Prev: What’s New In Python 3 8,  Up: What’s New in Python

1.7 What’s New In Python 3.7
============================


Editor: Elvis Pranskevichus <<elvis@magic.io>>

This article explains the new features in Python 3.7, compared to 3.6.
Python 3.7 was released on June 27, 2018.  For full details, see the
*note changelog: 13c.

* Menu:

* Summary – Release Highlights: Summary – Release Highlights<2>.
* New Features: New Features<12>.
* Other Language Changes: Other Language Changes<7>.
* New Modules: New Modules<7>.
* Improved Modules: Improved Modules<7>.
* C API Changes: C API Changes<6>.
* Build Changes: Build Changes<6>.
* Optimizations: Optimizations<7>.
* Other CPython Implementation Changes: Other CPython Implementation Changes<2>.
* Deprecated Python Behavior::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods.
* Deprecated functions and types of the C API::
* Platform Support Removals::
* API and Feature Removals: API and Feature Removals<2>.
* Module Removals::
* Windows-only Changes::
* Porting to Python 3.7: Porting to Python 3 7.
* Notable changes in Python 3.7.1: Notable changes in Python 3 7 1.
* Notable changes in Python 3.7.2: Notable changes in Python 3 7 2.
* Notable changes in Python 3.7.6: Notable changes in Python 3 7 6.
* Notable changes in Python 3.7.10: Notable changes in Python 3 7 10.
* Notable changes in Python 3.7.11: Notable changes in Python 3 7 11.
* Notable security feature in 3.7.14: Notable security feature in 3 7 14.


File: python.info,  Node: Summary – Release Highlights<2>,  Next: New Features<12>,  Up: What’s New In Python 3 7

1.7.1 Summary – Release Highlights
----------------------------------

New syntax features:

   * *note PEP 563: ad5, postponed evaluation of type annotations.

Backwards incompatible syntax changes:

   * *note async: 735. and *note await: 1b9. are now reserved keywords.

New library modules:

   * *note contextvars: 24.: *note PEP 567 – Context Variables: ad6.

   * *note dataclasses: 2f.: *note PEP 557 – Data Classes: ad7.

   * *note importlib.resources: ad8.

New built-in features:

   * *note PEP 553: ad9, the new *note breakpoint(): 234. function.

Python data model improvements:

   * *note PEP 562: ada, customization of access to module attributes.

   * *note PEP 560: adb, core support for typing module and generic
     types.

   * the insertion-order preservation nature of *note dict: adc. objects
     has been declared(1) to be an official part of the Python language
     spec.

Significant improvements in the standard library:

   * The *note asyncio: a. module has received new features, significant
     *note usability and performance improvements: add.

   * The *note time: ee. module gained support for *note functions with
     nanosecond resolution: ade.

CPython implementation improvements:

   * Avoiding the use of ASCII as a default text encoding:

        * *note PEP 538: adf, legacy C locale coercion

        * *note PEP 540: ae0, forced UTF-8 runtime mode

   * *note PEP 552: ae1, deterministic .pycs

   * *note New Python Development Mode: ae2.

   * *note PEP 565: ae3, improved *note DeprecationWarning: 1a5.
     handling

C API improvements:

   * *note PEP 539: ae4, new C API for thread-local storage

Documentation improvements:

   * *note PEP 545: ae5, Python documentation translations

   * New documentation translations: Japanese(2), French(3), and
     Korean(4).

This release features notable performance improvements in many areas.
The *note Optimizations: ae6. section lists them in detail.

For a list of changes that may affect compatibility with previous Python
releases please refer to the *note Porting to Python 3.7: ae7. section.

   ---------- Footnotes ----------

   (1) 
https://mail.python.org/pipermail/python-dev/2017-December/151283.html

   (2) https://docs.python.org/ja/

   (3) https://docs.python.org/fr/

   (4) https://docs.python.org/ko/


File: python.info,  Node: New Features<12>,  Next: Other Language Changes<7>,  Prev: Summary – Release Highlights<2>,  Up: What’s New In Python 3 7

1.7.2 New Features
------------------

* Menu:

* PEP 563; Postponed Evaluation of Annotations: PEP 563 Postponed Evaluation of Annotations.
* PEP 538; Legacy C Locale Coercion: PEP 538 Legacy C Locale Coercion.
* PEP 540; Forced UTF-8 Runtime Mode: PEP 540 Forced UTF-8 Runtime Mode.
* PEP 553; Built-in breakpoint(): PEP 553 Built-in breakpoint.
* PEP 539; New C API for Thread-Local Storage: PEP 539 New C API for Thread-Local Storage.
* PEP 562; Customization of Access to Module Attributes: PEP 562 Customization of Access to Module Attributes.
* PEP 564; New Time Functions With Nanosecond Resolution: PEP 564 New Time Functions With Nanosecond Resolution.
* PEP 565; Show DeprecationWarning in __main__: PEP 565 Show DeprecationWarning in __main__.
* PEP 560; Core Support for typing module and Generic Types: PEP 560 Core Support for typing module and Generic Types.
* PEP 552; Hash-based .pyc Files: PEP 552 Hash-based pyc Files.
* PEP 545; Python Documentation Translations: PEP 545 Python Documentation Translations.
* Python Development Mode (-X dev): Python Development Mode -X dev.


File: python.info,  Node: PEP 563 Postponed Evaluation of Annotations,  Next: PEP 538 Legacy C Locale Coercion,  Up: New Features<12>

1.7.2.1 PEP 563: Postponed Evaluation of Annotations
....................................................

The advent of type hints in Python uncovered two glaring usability
issues with the functionality of annotations added in PEP 3107(1) and
refined further in PEP 526(2):

   * annotations could only use names which were already available in
     the current scope, in other words they didn’t support forward
     references of any kind; and

   * annotating source code had adverse effects on startup time of
     Python programs.

Both of these issues are fixed by postponing the evaluation of
annotations.  Instead of compiling code which executes expressions in
annotations at their definition time, the compiler stores the annotation
in a string form equivalent to the AST of the expression in question.
If needed, annotations can be resolved at runtime using *note
typing.get_type_hints(): 6b4.  In the common case where this is not
required, the annotations are cheaper to store (since short strings are
interned by the interpreter) and make startup time faster.

Usability-wise, annotations now support forward references, making the
following syntax valid:

     class C:
         @classmethod
         def from_string(cls, source: str) -> C:
             ...

         def validate_b(self, obj: B) -> bool:
             ...

     class B:
         ...

Since this change breaks compatibility, the new behavior needs to be
enabled on a per-module basis in Python 3.7 using a *note __future__: 0.
import:

     from __future__ import annotations

It will become the default in Python 3.10.

See also
........

PEP 563(3) – Postponed evaluation of annotations

     PEP written and implemented by Łukasz Langa.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3107/

   (2) https://peps.python.org/pep-0526/

   (3) https://peps.python.org/pep-0563/


File: python.info,  Node: PEP 538 Legacy C Locale Coercion,  Next: PEP 540 Forced UTF-8 Runtime Mode,  Prev: PEP 563 Postponed Evaluation of Annotations,  Up: New Features<12>

1.7.2.2 PEP 538: Legacy C Locale Coercion
.........................................

An ongoing challenge within the Python 3 series has been determining a
sensible default strategy for handling the “7-bit ASCII” text encoding
assumption currently implied by the use of the default C or POSIX locale
on non-Windows platforms.

PEP 538(1) updates the default interpreter command line interface to
automatically coerce that locale to an available UTF-8 based locale as
described in the documentation of the new *note PYTHONCOERCECLOCALE:
aeb. environment variable.  Automatically setting ‘LC_CTYPE’ this way
means that both the core interpreter and locale-aware C extensions (such
as *note readline: ba.) will assume the use of UTF-8 as the default text
encoding, rather than ASCII.

The platform support definition in PEP 11(2) has also been updated to
limit full text handling support to suitably configured non-ASCII based
locales.

As part of this change, the default error handler for *note stdin: 540.
and *note stdout: aec. is now ‘surrogateescape’ (rather than ‘strict’)
when using any of the defined coercion target locales (currently
‘C.UTF-8’, ‘C.utf8’, and ‘UTF-8’).  The default error handler for *note
stderr: 943. continues to be ‘backslashreplace’, regardless of locale.

Locale coercion is silent by default, but to assist in debugging
potentially locale related integration problems, explicit warnings
(emitted directly on *note stderr: 943.) can be requested by setting
‘PYTHONCOERCECLOCALE=warn’.  This setting will also cause the Python
runtime to emit a warning if the legacy C locale remains active when the
core interpreter is initialized.

While PEP 538(3)’s locale coercion has the benefit of also affecting
extension modules (such as GNU ‘readline’), as well as child processes
(including those running non-Python applications and older versions of
Python), it has the downside of requiring that a suitable target locale
be present on the running system.  To better handle the case where no
suitable target locale is available (as occurs on RHEL/CentOS 7, for
example), Python 3.7 also implements *note PEP 540; Forced UTF-8 Runtime
Mode: ae0.

See also
........

PEP 538(4) – Coercing the legacy C locale to a UTF-8 based locale

     PEP written and implemented by Nick Coghlan.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0538/

   (2) https://peps.python.org/pep-0011/

   (3) https://peps.python.org/pep-0538/

   (4) https://peps.python.org/pep-0538/


File: python.info,  Node: PEP 540 Forced UTF-8 Runtime Mode,  Next: PEP 553 Built-in breakpoint,  Prev: PEP 538 Legacy C Locale Coercion,  Up: New Features<12>

1.7.2.3 PEP 540: Forced UTF-8 Runtime Mode
..........................................

The new *note -X: 176. ‘utf8’ command line option and *note PYTHONUTF8:
aee. environment variable can be used to enable the *note Python UTF-8
Mode: 659.

When in UTF-8 mode, CPython ignores the locale settings, and uses the
UTF-8 encoding by default.  The error handlers for *note sys.stdin: 540.
and *note sys.stdout: aec. streams are set to ‘surrogateescape’.

The forced UTF-8 mode can be used to change the text handling behavior
in an embedded Python interpreter without changing the locale settings
of an embedding application.

While PEP 540(1)’s UTF-8 mode has the benefit of working regardless of
which locales are available on the running system, it has the downside
of having no effect on extension modules (such as GNU ‘readline’), child
processes running non-Python applications, and child processes running
older versions of Python.  To reduce the risk of corrupting text data
when communicating with such components, Python 3.7 also implements
*note PEP 540; Forced UTF-8 Runtime Mode: ae0.).

The UTF-8 mode is enabled by default when the locale is ‘C’ or ‘POSIX’,
and the PEP 538(2) locale coercion feature fails to change it to a UTF-8
based alternative (whether that failure is due to
‘PYTHONCOERCECLOCALE=0’ being set, ‘LC_ALL’ being set, or the lack of a
suitable target locale).

See also
........

PEP 540(3) – Add a new UTF-8 mode

     PEP written and implemented by Victor Stinner

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0540/

   (2) https://peps.python.org/pep-0538/

   (3) https://peps.python.org/pep-0540/


File: python.info,  Node: PEP 553 Built-in breakpoint,  Next: PEP 539 New C API for Thread-Local Storage,  Prev: PEP 540 Forced UTF-8 Runtime Mode,  Up: New Features<12>

1.7.2.4 PEP 553: Built-in ‘breakpoint()’
........................................

Python 3.7 includes the new built-in *note breakpoint(): 234. function
as an easy and consistent way to enter the Python debugger.

Built-in ‘breakpoint()’ calls *note sys.breakpointhook(): af0.  By
default, the latter imports *note pdb: a5. and then calls
‘pdb.set_trace()’, but by binding ‘sys.breakpointhook()’ to the function
of your choosing, ‘breakpoint()’ can enter any debugger.  Additionally,
the environment variable *note PYTHONBREAKPOINT: af1. can be set to the
callable of your debugger of choice.  Set ‘PYTHONBREAKPOINT=0’ to
completely disable built-in ‘breakpoint()’.

See also
........

PEP 553(1) – Built-in breakpoint()

     PEP written and implemented by Barry Warsaw

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0553/


File: python.info,  Node: PEP 539 New C API for Thread-Local Storage,  Next: PEP 562 Customization of Access to Module Attributes,  Prev: PEP 553 Built-in breakpoint,  Up: New Features<12>

1.7.2.5 PEP 539: New C API for Thread-Local Storage
...................................................

While Python provides a C API for thread-local storage support; the
existing *note Thread Local Storage (TLS) API: af3. has used int to
represent TLS keys across all platforms.  This has not generally been a
problem for officially support platforms, but that is neither
POSIX-compliant, nor portable in any practical sense.

PEP 539(1) changes this by providing a new *note Thread Specific Storage
(TSS) API: af4. to CPython which supersedes use of the existing TLS API
within the CPython interpreter, while deprecating the existing API. The
TSS API uses a new type *note Py_tss_t: af5. instead of int to represent
TSS keys–an opaque type the definition of which may depend on the
underlying TLS implementation.  Therefore, this will allow to build
CPython on platforms where the native TLS key is defined in a way that
cannot be safely cast to int.

Note that on platforms where the native TLS key is defined in a way that
cannot be safely cast to int, all functions of the existing TLS API will
be no-op and immediately return failure.  This indicates clearly that
the old API is not supported on platforms where it cannot be used
reliably, and that no effort will be made to add such support.

See also
........

PEP 539(2) – A New C-API for Thread-Local Storage in CPython

     PEP written by Erik M. Bray; implementation by Masayuki Yamamoto.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0539/

   (2) https://peps.python.org/pep-0539/


File: python.info,  Node: PEP 562 Customization of Access to Module Attributes,  Next: PEP 564 New Time Functions With Nanosecond Resolution,  Prev: PEP 539 New C API for Thread-Local Storage,  Up: New Features<12>

1.7.2.6 PEP 562: Customization of Access to Module Attributes
.............................................................

Python 3.7 allows defining *note __getattr__(): af7. on modules and will
call it whenever a module attribute is otherwise not found.  Defining
*note __dir__(): af8. on modules is now also allowed.

A typical example of where this may be useful is module attribute
deprecation and lazy loading.

See also
........

PEP 562(1) – Module ‘__getattr__’ and ‘__dir__’

     PEP written and implemented by Ivan Levkivskyi

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0562/


File: python.info,  Node: PEP 564 New Time Functions With Nanosecond Resolution,  Next: PEP 565 Show DeprecationWarning in __main__,  Prev: PEP 562 Customization of Access to Module Attributes,  Up: New Features<12>

1.7.2.7 PEP 564: New Time Functions With Nanosecond Resolution
..............................................................

The resolution of clocks in modern systems can exceed the limited
precision of a floating-point number returned by the *note time.time():
254. function and its variants.  To avoid loss of precision, PEP 564(1)
adds six new “nanosecond” variants of the existing timer functions to
the *note time: ee. module:

   * *note time.clock_gettime_ns(): afa.

   * *note time.clock_settime_ns(): afb.

   * *note time.monotonic_ns(): afc.

   * *note time.perf_counter_ns(): afd.

   * *note time.process_time_ns(): afe.

   * *note time.time_ns(): aff.

The new functions return the number of nanoseconds as an integer value.

Measurements(2) show that on Linux and Windows the resolution of *note
time.time_ns(): aff. is approximately 3 times better than that of *note
time.time(): 254.

See also
........

PEP 564(3) – Add new time functions with nanosecond resolution

     PEP written and implemented by Victor Stinner

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0564/

   (2) 
https://peps.python.org/pep-0564/#annex-clocks-resolution-in-python

   (3) https://peps.python.org/pep-0564/


File: python.info,  Node: PEP 565 Show DeprecationWarning in __main__,  Next: PEP 560 Core Support for typing module and Generic Types,  Prev: PEP 564 New Time Functions With Nanosecond Resolution,  Up: New Features<12>

1.7.2.8 PEP 565: Show DeprecationWarning in ‘__main__’
......................................................

The default handling of *note DeprecationWarning: 1a5. has been changed
such that these warnings are once more shown by default, but only when
the code triggering them is running directly in the *note __main__: 1.
module.  As a result, developers of single file scripts and those using
Python interactively should once again start seeing deprecation warnings
for the APIs they use, but deprecation warnings triggered by imported
application, library and framework modules will continue to be hidden by
default.

As a result of this change, the standard library now allows developers
to choose between three different deprecation warning behaviours:

   * *note FutureWarning: 418.: always displayed by default, recommended
     for warnings intended to be seen by application end users (e.g.
     for deprecated application configuration settings).

   * *note DeprecationWarning: 1a5.: displayed by default only in *note
     __main__: 1. and when running tests, recommended for warnings
     intended to be seen by other Python developers where a version
     upgrade may result in changed behaviour or an error.

   * *note PendingDeprecationWarning: 8d1.: displayed by default only
     when running tests, intended for cases where a future version
     upgrade will change the warning category to *note
     DeprecationWarning: 1a5. or *note FutureWarning: 418.

Previously both *note DeprecationWarning: 1a5. and *note
PendingDeprecationWarning: 8d1. were only visible when running tests,
which meant that developers primarily writing single file scripts or
using Python interactively could be surprised by breaking changes in the
APIs they used.

See also
........

PEP 565(1) – Show DeprecationWarning in ‘__main__’

     PEP written and implemented by Nick Coghlan

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0565/


File: python.info,  Node: PEP 560 Core Support for typing module and Generic Types,  Next: PEP 552 Hash-based pyc Files,  Prev: PEP 565 Show DeprecationWarning in __main__,  Up: New Features<12>

1.7.2.9 PEP 560: Core Support for ‘typing’ module and Generic Types
...................................................................

Initially PEP 484(1) was designed in such way that it would not
introduce 'any' changes to the core CPython interpreter.  Now type hints
and the *note typing: 104. module are extensively used by the community,
so this restriction is removed.  The PEP introduces two special methods
*note __class_getitem__(): 73e. and *note __mro_entries__(): b02, these
methods are now used by most classes and special constructs in ‘typing’.
As a result, the speed of various operations with types increased up to
7 times, the generic types can be used without metaclass conflicts, and
several long standing bugs in ‘typing’ module are fixed.

See also
........

PEP 560(2) – Core support for typing module and generic types

     PEP written and implemented by Ivan Levkivskyi

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0560/


File: python.info,  Node: PEP 552 Hash-based pyc Files,  Next: PEP 545 Python Documentation Translations,  Prev: PEP 560 Core Support for typing module and Generic Types,  Up: New Features<12>

1.7.2.10 PEP 552: Hash-based .pyc Files
.......................................

Python has traditionally checked the up-to-dateness of bytecode cache
files (i.e., ‘.pyc’ files) by comparing the source metadata
(last-modified timestamp and size) with source metadata saved in the
cache file header when it was generated.  While effective, this
invalidation method has its drawbacks.  When filesystem timestamps are
too coarse, Python can miss source updates, leading to user confusion.
Additionally, having a timestamp in the cache file is problematic for
build reproducibility(1) and content-based build systems.

PEP 552(2) extends the pyc format to allow the hash of the source file
to be used for invalidation instead of the source timestamp.  Such
‘.pyc’ files are called “hash-based”.  By default, Python still uses
timestamp-based invalidation and does not generate hash-based ‘.pyc’
files at runtime.  Hash-based ‘.pyc’ files may be generated with *note
py_compile: b3. or *note compileall: 20.

Hash-based ‘.pyc’ files come in two variants: checked and unchecked.
Python validates checked hash-based ‘.pyc’ files against the
corresponding source files at runtime but doesn’t do so for unchecked
hash-based pycs.  Unchecked hash-based ‘.pyc’ files are a useful
performance optimization for environments where a system external to
Python (e.g., the build system) is responsible for keeping ‘.pyc’ files
up-to-date.

See *note Cached bytecode invalidation: 5ef. for more information.

See also
........

PEP 552(3) – Deterministic pycs

     PEP written and implemented by Benjamin Peterson

   ---------- Footnotes ----------

   (1) https://reproducible-builds.org/

   (2) https://peps.python.org/pep-0552/

   (3) https://peps.python.org/pep-0552/


File: python.info,  Node: PEP 545 Python Documentation Translations,  Next: Python Development Mode -X dev,  Prev: PEP 552 Hash-based pyc Files,  Up: New Features<12>

1.7.2.11 PEP 545: Python Documentation Translations
...................................................

PEP 545(1) describes the process of creating and maintaining Python
documentation translations.

Three new translations have been added:

   - Japanese: ‘https://docs.python.org/ja/’

   - French: ‘https://docs.python.org/fr/’

   - Korean: ‘https://docs.python.org/ko/’

See also
........

PEP 545(2) – Python Documentation Translations

     PEP written and implemented by Julien Palard, Inada Naoki, and
     Victor Stinner.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0545/

   (2) https://peps.python.org/pep-0545/


File: python.info,  Node: Python Development Mode -X dev,  Prev: PEP 545 Python Documentation Translations,  Up: New Features<12>

1.7.2.12 Python Development Mode (-X dev)
.........................................

The new *note -X: 176. ‘dev’ command line option or the new *note
PYTHONDEVMODE: b06. environment variable can be used to enable *note
Python Development Mode: 1f8.  When in development mode, Python performs
additional runtime checks that are too expensive to be enabled by
default.  See *note Python Development Mode: 1f8. documentation for the
full description.


File: python.info,  Node: Other Language Changes<7>,  Next: New Modules<7>,  Prev: New Features<12>,  Up: What’s New In Python 3 7

1.7.3 Other Language Changes
----------------------------

   * An *note await: 1b9. expression and comprehensions containing an
     *note async for: ac0. clause were illegal in the expressions in
     *note formatted string literals: 9b4. due to a problem with the
     implementation.  In Python 3.7 this restriction was lifted.

   * More than 255 arguments can now be passed to a function, and a
     function can now have more than 255 parameters.  (Contributed by
     Serhiy Storchaka in bpo-12844(1) and bpo-18896(2).)

   * *note bytes.fromhex(): b08. and *note bytearray.fromhex(): b09. now
     ignore all ASCII whitespace, not only spaces.  (Contributed by
     Robert Xiao in bpo-28927(3).)

   * *note str: 44f, *note bytes: 1c2, and *note bytearray: 2ea. gained
     support for the new *note isascii(): b0a. method, which can be used
     to test if a string or bytes contain only the ASCII characters.
     (Contributed by INADA Naoki in bpo-32677(4).)

   * *note ImportError: 41c. now displays module name and module
     ‘__file__’ path when ‘from ... import ...’ fails.  (Contributed by
     Matthias Bussonnier in bpo-29546(5).)

   * Circular imports involving absolute imports with binding a
     submodule to a name are now supported.  (Contributed by Serhiy
     Storchaka in bpo-30024(6).)

   * ‘object.__format__(x, '')’ is now equivalent to ‘str(x)’ rather
     than ‘format(str(self), '')’.  (Contributed by Serhiy Storchaka in
     bpo-28974(7).)

   * In order to better support dynamic creation of stack traces, *note
     types.TracebackType: b0b. can now be instantiated from Python code,
     and the *note tb_next: b0c. attribute on *note tracebacks: b0d. is
     now writable.  (Contributed by Nathaniel J. Smith in bpo-30579(8).)

   * When using the *note -m: 5e4. switch, ‘sys.path[0]’ is now eagerly
     expanded to the full starting directory path, rather than being
     left as the empty directory (which allows imports from the
     'current' working directory at the time when an import occurs)
     (Contributed by Nick Coghlan in bpo-33053(9).)

   * The new *note -X: 176. ‘importtime’ option or the *note
     PYTHONPROFILEIMPORTTIME: b0e. environment variable can be used to
     show the timing of each module import.  (Contributed by Inada Naoki
     in bpo-31415(10).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12844

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18896

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28927

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32677

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29546

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30024

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28974

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30579

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33053

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31415


File: python.info,  Node: New Modules<7>,  Next: Improved Modules<7>,  Prev: Other Language Changes<7>,  Up: What’s New In Python 3 7

1.7.4 New Modules
-----------------

* Menu:

* contextvars::
* dataclasses: dataclasses<3>.
* importlib.resources: importlib resources<2>.


File: python.info,  Node: contextvars,  Next: dataclasses<3>,  Up: New Modules<7>

1.7.4.1 contextvars
...................

The new *note contextvars: 24. module and a set of *note new C APIs:
b11. introduce support for 'context variables'.  Context variables are
conceptually similar to thread-local variables.  Unlike TLS, context
variables support asynchronous code correctly.

The *note asyncio: a. and *note decimal: 36. modules have been updated
to use and support context variables out of the box.  Particularly the
active decimal context is now stored in a context variable, which allows
decimal operations to work with the correct context in asynchronous
code.

See also
........

PEP 567(1) – Context Variables

     PEP written and implemented by Yury Selivanov

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0567/


File: python.info,  Node: dataclasses<3>,  Next: importlib resources<2>,  Prev: contextvars,  Up: New Modules<7>

1.7.4.2 dataclasses
...................

The new *note dataclass(): 1cb. decorator provides a way to declare
'data classes'.  A data class describes its attributes using class
variable annotations.  Its constructor and other magic methods, such as
*note __repr__(): 61f, *note __eq__(): b13, and *note __hash__(): b14.
are generated automatically.

Example:

     @dataclass
     class Point:
         x: float
         y: float
         z: float = 0.0

     p = Point(1.5, 2.5)
     print(p)   # produces "Point(x=1.5, y=2.5, z=0.0)"

See also
........

PEP 557(1) – Data Classes

     PEP written and implemented by Eric V. Smith

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0557/


File: python.info,  Node: importlib resources<2>,  Prev: dataclasses<3>,  Up: New Modules<7>

1.7.4.3 importlib.resources
...........................

The new *note importlib.resources: 7b. module provides several new APIs
and one new ABC for access to, opening, and reading 'resources' inside
packages.  Resources are roughly similar to files inside packages, but
they needn’t be actual files on the physical file system.  Module
loaders can provide a ‘get_resource_reader()’ function which returns a
*note importlib.abc.ResourceReader: b16. instance to support this new
API. Built-in file path loaders and zip file loaders both support this.

Contributed by Barry Warsaw and Brett Cannon in bpo-32248(1).

See also
........

importlib_resources(2) – a PyPI backport for earlier Python versions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32248

   (2) https://importlib-resources.readthedocs.io/en/latest/


File: python.info,  Node: Improved Modules<7>,  Next: C API Changes<6>,  Prev: New Modules<7>,  Up: What’s New In Python 3 7

1.7.5 Improved Modules
----------------------

* Menu:

* argparse: argparse<3>.
* asyncio: asyncio<7>.
* binascii::
* calendar: calendar<2>.
* collections: collections<2>.
* compileall: compileall<3>.
* concurrent.futures: concurrent futures<3>.
* contextlib: contextlib<3>.
* cProfile: cProfile<2>.
* crypt::
* datetime: datetime<4>.
* dbm: dbm<2>.
* decimal::
* dis: dis<3>.
* distutils: distutils<4>.
* enum: enum<5>.
* functools: functools<3>.
* gc: gc<4>.
* hmac: hmac<2>.
* http.client: http client.
* http.server: http server.
* idlelib and IDLE::
* importlib: importlib<4>.
* io: io<4>.
* ipaddress: ipaddress<3>.
* itertools: itertools<5>.
* locale: locale<4>.
* logging: logging<3>.
* math: math<6>.
* mimetypes: mimetypes<2>.
* msilib::
* multiprocessing: multiprocessing<4>.
* os: os<7>.
* pathlib: pathlib<8>.
* pdb: pdb<4>.
* py_compile: py_compile<3>.
* pydoc: pydoc<2>.
* queue: queue<2>.
* re: re<4>.
* signal: signal<2>.
* socket: socket<5>.
* socketserver::
* sqlite3: sqlite3<6>.
* ssl: ssl<5>.
* string: string<2>.
* subprocess: subprocess<2>.
* sys: sys<8>.
* time: time<5>.
* tkinter: tkinter<5>.
* tracemalloc: tracemalloc<2>.
* types: types<4>.
* unicodedata: unicodedata<6>.
* unittest: unittest<7>.
* unittest.mock: unittest mock.
* urllib.parse: urllib parse<5>.
* uu::
* uuid: uuid<2>.
* warnings: warnings<3>.
* xml: xml<5>.
* xml.etree: xml etree.
* xmlrpc.server: xmlrpc server.
* zipapp::
* zipfile: zipfile<2>.


File: python.info,  Node: argparse<3>,  Next: asyncio<7>,  Up: Improved Modules<7>

1.7.5.1 argparse
................

The new *note ArgumentParser.parse_intermixed_args(): b19. method allows
intermixing options and positional arguments.  (Contributed by paul.j3
in bpo-14191(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14191


File: python.info,  Node: asyncio<7>,  Next: binascii,  Prev: argparse<3>,  Up: Improved Modules<7>

1.7.5.2 asyncio
...............

The *note asyncio: a. module has received many new features, usability
and *note performance improvements: b1b.  Notable changes include:

   * The new *note provisional: b1c. *note asyncio.run(): 47f. function
     can be used to run a coroutine from synchronous code by
     automatically creating and destroying the event loop.  (Contributed
     by Yury Selivanov in bpo-32314(1).)

   * asyncio gained support for *note contextvars: 24.  *note
     loop.call_soon(): b1d, *note loop.call_soon_threadsafe(): b1e,
     *note loop.call_later(): b1f, *note loop.call_at(): b20, and *note
     Future.add_done_callback(): b21. have a new optional keyword-only
     'context' parameter.  *note Tasks: 1be. now track their context
     automatically.  See PEP 567(2) for more details.  (Contributed by
     Yury Selivanov in bpo-32436(3).)

   * The new *note asyncio.create_task(): 1bf. function has been added
     as a shortcut to ‘asyncio.get_event_loop().create_task()’.
     (Contributed by Andrew Svetlov in bpo-32311(4).)

   * The new *note loop.start_tls(): b22. method can be used to upgrade
     an existing connection to TLS. (Contributed by Yury Selivanov in
     bpo-23749(5).)

   * The new *note loop.sock_recv_into(): b23. method allows reading
     data from a socket directly into a provided buffer making it
     possible to reduce data copies.  (Contributed by Antoine Pitrou in
     bpo-31819(6).)

   * The new *note asyncio.current_task(): 480. function returns the
     currently running *note Task: 1be. instance, and the new *note
     asyncio.all_tasks(): 960. function returns a set of all existing
     ‘Task’ instances in a given loop.  The ‘Task.current_task()’ and
     ‘Task.all_tasks()’ methods have been deprecated.  (Contributed by
     Andrew Svetlov in bpo-32250(7).)

   * The new 'provisional' *note BufferedProtocol: ab2. class allows
     implementing streaming protocols with manual control over the
     receive buffer.  (Contributed by Yury Selivanov in bpo-32251(8).)

   * The new *note asyncio.get_running_loop(): b24. function returns the
     currently running loop, and raises a *note RuntimeError: 195. if no
     loop is running.  This is in contrast with *note
     asyncio.get_event_loop(): 2c2, which will 'create' a new event loop
     if none is running.  (Contributed by Yury Selivanov in
     bpo-32269(9).)

   * The new *note StreamWriter.wait_closed(): b25. coroutine method
     allows waiting until the stream writer is closed.  The new *note
     StreamWriter.is_closing(): b26. method can be used to determine if
     the writer is closing.  (Contributed by Andrew Svetlov in
     bpo-32391(10).)

   * The new *note loop.sock_sendfile(): b27. coroutine method allows
     sending files using *note os.sendfile: b28. when possible.
     (Contributed by Andrew Svetlov in bpo-32410(11).)

   * The new *note Future.get_loop(): b29. and ‘Task.get_loop()’ methods
     return the instance of the loop on which a task or a future were
     created.  *note Server.get_loop(): b2a. allows doing the same for
     *note asyncio.Server: b2b. objects.  (Contributed by Yury Selivanov
     in bpo-32415(12) and Srinivas Reddy Thatiparthy in bpo-32418(13).)

   * It is now possible to control how instances of *note
     asyncio.Server: b2b. begin serving.  Previously, the server would
     start serving immediately when created.  The new 'start_serving'
     keyword argument to *note loop.create_server(): b2c. and *note
     loop.create_unix_server(): 1ae, as well as *note
     Server.start_serving(): b2d, and *note Server.serve_forever(): b2e.
     can be used to decouple server instantiation and serving.  The new
     *note Server.is_serving(): b2f. method returns ‘True’ if the server
     is serving.  ‘Server’ objects are now asynchronous context
     managers:

          srv = await loop.create_server(...)

          async with srv:
              # some code

          # At this point, srv is closed and no longer accepts new connections.

     (Contributed by Yury Selivanov in bpo-32662(14).)

   * Callback objects returned by *note loop.call_later(): b1f. gained
     the new *note when(): b30. method which returns an absolute
     scheduled callback timestamp.  (Contributed by Andrew Svetlov in
     bpo-32741(15).)

   * The *note loop.create_datagram_endpoint(): 736. method gained
     support for Unix sockets.  (Contributed by Quentin Dawans in
     bpo-31245(16).)

   * The *note asyncio.open_connection(): b31, *note
     asyncio.start_server(): b32. functions, *note
     loop.create_connection(): 606, *note loop.create_server(): b2c,
     *note loop.create_accepted_socket(): 7e2. methods and their
     corresponding UNIX socket variants now accept the
     'ssl_handshake_timeout' keyword argument.  (Contributed by Neil
     Aspinall in bpo-29970(17).)

   * The new *note Handle.cancelled(): b33. method returns ‘True’ if the
     callback was cancelled.  (Contributed by Marat Sharafutdinov in
     bpo-31943(18).)

   * The asyncio source has been converted to use the *note async:
     735./*note await: 1b9. syntax.  (Contributed by Andrew Svetlov in
     bpo-32193(19).)

   * The new *note ReadTransport.is_reading(): b34. method can be used
     to determine the reading state of the transport.  Additionally,
     calls to *note ReadTransport.resume_reading(): b35. and *note
     ReadTransport.pause_reading(): b36. are now idempotent.
     (Contributed by Yury Selivanov in bpo-32356(20).)

   * Loop methods which accept socket paths now support passing *note
     path-like objects: 2a0.  (Contributed by Yury Selivanov in
     bpo-32066(21).)

   * In *note asyncio: a. TCP sockets on Linux are now created with
     ‘TCP_NODELAY’ flag set by default.  (Contributed by Yury Selivanov
     and Victor Stinner in bpo-27456(22).)

   * Exceptions occurring in cancelled tasks are no longer logged.
     (Contributed by Yury Selivanov in bpo-30508(23).)

   * New ‘WindowsSelectorEventLoopPolicy’ and
     ‘WindowsProactorEventLoopPolicy’ classes.  (Contributed by Yury
     Selivanov in bpo-33792(24).)

Several ‘asyncio’ APIs have been *note deprecated: b37.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32314

   (2) https://peps.python.org/pep-0567/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32311

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23749

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31819

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32250

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32251

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32269

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32391

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32410

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32415

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32418

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32662

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32741

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31245

   (17) https://bugs.python.org/issue?@action=redirect&bpo=29970

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31943

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32193

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32356

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32066

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27456

   (23) https://bugs.python.org/issue?@action=redirect&bpo=30508

   (24) https://bugs.python.org/issue?@action=redirect&bpo=33792


File: python.info,  Node: binascii,  Next: calendar<2>,  Prev: asyncio<7>,  Up: Improved Modules<7>

1.7.5.3 binascii
................

The *note b2a_uu(): b39. function now accepts an optional 'backtick'
keyword argument.  When it’s true, zeros are represented by ‘'`'’
instead of spaces.  (Contributed by Xiang Zhang in bpo-30103(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30103


File: python.info,  Node: calendar<2>,  Next: collections<2>,  Prev: binascii,  Up: Improved Modules<7>

1.7.5.4 calendar
................

The *note HTMLCalendar: b3b. class has new class attributes which ease
the customization of CSS classes in the produced HTML calendar.
(Contributed by Oz Tiram in bpo-30095(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30095


File: python.info,  Node: collections<2>,  Next: compileall<3>,  Prev: calendar<2>,  Up: Improved Modules<7>

1.7.5.5 collections
...................

‘collections.namedtuple()’ now supports default values.  (Contributed by
Raymond Hettinger in bpo-32320(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32320


File: python.info,  Node: compileall<3>,  Next: concurrent futures<3>,  Prev: collections<2>,  Up: Improved Modules<7>

1.7.5.6 compileall
..................

*note compileall.compile_dir(): b3e. learned the new 'invalidation_mode'
parameter, which can be used to enable *note hash-based .pyc
invalidation: ae1.  The invalidation mode can also be specified on the
command line using the new ‘--invalidation-mode’ argument.  (Contributed
by Benjamin Peterson in bpo-31650(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31650


File: python.info,  Node: concurrent futures<3>,  Next: contextlib<3>,  Prev: compileall<3>,  Up: Improved Modules<7>

1.7.5.7 concurrent.futures
..........................

*note ProcessPoolExecutor: 8f7. and *note ThreadPoolExecutor: 745. now
support the new 'initializer' and 'initargs' constructor arguments.
(Contributed by Antoine Pitrou in bpo-21423(1).)

The *note ProcessPoolExecutor: 8f7. can now take the multiprocessing
context via the new 'mp_context' argument.  (Contributed by Thomas
Moreau in bpo-31540(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21423

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31540


File: python.info,  Node: contextlib<3>,  Next: cProfile<2>,  Prev: concurrent futures<3>,  Up: Improved Modules<7>

1.7.5.8 contextlib
..................

The new *note nullcontext(): 7f3. is a simpler and faster no-op context
manager than *note ExitStack: b41.  (Contributed by Jesse-Bakker in
bpo-10049(1).)

The new *note asynccontextmanager(): b42, *note
AbstractAsyncContextManager: b43, and *note AsyncExitStack: b44. have
been added to complement their synchronous counterparts.  (Contributed
by Jelle Zijlstra in bpo-29679(2) and bpo-30241(3), and by Alexander
Mohr and Ilya Kulakov in bpo-29302(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10049

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29679

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30241

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29302


File: python.info,  Node: cProfile<2>,  Next: crypt,  Prev: contextlib<3>,  Up: Improved Modules<7>

1.7.5.9 cProfile
................

The *note cProfile: 27. command line now accepts ‘-m module_name’ as an
alternative to script path.  (Contributed by Sanyam Khurana in
bpo-21862(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21862


File: python.info,  Node: crypt,  Next: datetime<4>,  Prev: cProfile<2>,  Up: Improved Modules<7>

1.7.5.10 crypt
..............

The ‘crypt’ module now supports the Blowfish hashing method.
(Contributed by Serhiy Storchaka in bpo-31664(1).)

The ‘mksalt()’ function now allows specifying the number of rounds for
hashing.  (Contributed by Serhiy Storchaka in bpo-31702(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31664

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31702


File: python.info,  Node: datetime<4>,  Next: dbm<2>,  Prev: crypt,  Up: Improved Modules<7>

1.7.5.11 datetime
.................

The new *note datetime.fromisoformat(): 61a. method constructs a *note
datetime: 1cc. object from a string in one of the formats output by
*note datetime.isoformat(): b48.  (Contributed by Paul Ganssle in
bpo-15873(1).)

The *note tzinfo: 5e1. class now supports sub-minute offsets.
(Contributed by Alexander Belopolsky in bpo-5288(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15873

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5288


File: python.info,  Node: dbm<2>,  Next: decimal,  Prev: datetime<4>,  Up: Improved Modules<7>

1.7.5.12 dbm
............

*note dbm.dumb: 32. now supports reading read-only files and no longer
writes the index file when it is not changed.


File: python.info,  Node: decimal,  Next: dis<3>,  Prev: dbm<2>,  Up: Improved Modules<7>

1.7.5.13 decimal
................

The *note decimal: 36. module now uses *note context variables: ad6. to
store the decimal context.  (Contributed by Yury Selivanov in
bpo-32630(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32630


File: python.info,  Node: dis<3>,  Next: distutils<4>,  Prev: decimal,  Up: Improved Modules<7>

1.7.5.14 dis
............

The *note dis(): b4c. function is now able to disassemble nested code
objects (the code of comprehensions, generator expressions and nested
functions, and the code used for building nested classes).  The maximum
depth of disassembly recursion is controlled by the new 'depth'
parameter.  (Contributed by Serhiy Storchaka in bpo-11822(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11822


File: python.info,  Node: distutils<4>,  Next: enum<5>,  Prev: dis<3>,  Up: Improved Modules<7>

1.7.5.15 distutils
..................

‘README.rst’ is now included in the list of distutils standard READMEs
and therefore included in source distributions.  (Contributed by Ryan
Gonzalez in bpo-11913(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11913


File: python.info,  Node: enum<5>,  Next: functools<3>,  Prev: distutils<4>,  Up: Improved Modules<7>

1.7.5.16 enum
.............

The *note Enum: 633. learned the new ‘_ignore_’ class property, which
allows listing the names of properties which should not become enum
members.  (Contributed by Ethan Furman in bpo-31801(1).)

In Python 3.8, attempting to check for non-Enum objects in *note Enum:
633. classes will raise a *note TypeError: 2c3. (e.g.  ‘1 in Color’);
similarly, attempting to check for non-Flag objects in a *note Flag:
626. member will raise ‘TypeError’ (e.g.  ‘1 in Perm.RW’); currently,
both operations return *note False: b4f. instead and are deprecated.
(Contributed by Ethan Furman in bpo-33217(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31801

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33217


File: python.info,  Node: functools<3>,  Next: gc<4>,  Prev: enum<5>,  Up: Improved Modules<7>

1.7.5.17 functools
..................

*note functools.singledispatch(): 63c. now supports registering
implementations using type annotations.  (Contributed by Łukasz Langa in
bpo-32227(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32227


File: python.info,  Node: gc<4>,  Next: hmac<2>,  Prev: functools<3>,  Up: Improved Modules<7>

1.7.5.18 gc
...........

The new *note gc.freeze(): b52. function allows freezing all objects
tracked by the garbage collector and excluding them from future
collections.  This can be used before a POSIX ‘fork()’ call to make the
GC copy-on-write friendly or to speed up collection.  The new *note
gc.unfreeze(): b53. functions reverses this operation.  Additionally,
*note gc.get_freeze_count(): b54. can be used to obtain the number of
frozen objects.  (Contributed by Li Zekun in bpo-31558(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31558


File: python.info,  Node: hmac<2>,  Next: http client,  Prev: gc<4>,  Up: Improved Modules<7>

1.7.5.19 hmac
.............

The *note hmac: 6a. module now has an optimized one-shot *note digest():
b56. function, which is up to three times faster than *note HMAC(): b57.
(Contributed by Christian Heimes in bpo-32433(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32433


File: python.info,  Node: http client,  Next: http server,  Prev: hmac<2>,  Up: Improved Modules<7>

1.7.5.20 http.client
....................

*note HTTPConnection: b59. and *note HTTPSConnection: b5a. now support
the new 'blocksize' argument for improved upload throughput.
(Contributed by Nir Soffer in bpo-31945(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31945


File: python.info,  Node: http server,  Next: idlelib and IDLE,  Prev: http client,  Up: Improved Modules<7>

1.7.5.21 http.server
....................

*note SimpleHTTPRequestHandler: b5c. now supports the HTTP
‘If-Modified-Since’ header.  The server returns the 304 response status
if the target file was not modified after the time specified in the
header.  (Contributed by Pierre Quentel in bpo-29654(1).)

*note SimpleHTTPRequestHandler: b5c. accepts the new 'directory'
argument, in addition to the new ‘--directory’ command line argument.
With this parameter, the server serves the specified directory, by
default it uses the current working directory.  (Contributed by Stéphane
Wirtel and Julien Palard in bpo-28707(2).)

The new *note ThreadingHTTPServer: b5d. class uses threads to handle
requests using *note ThreadingMixIn: b5e.  It is used when ‘http.server’
is run with ‘-m’.  (Contributed by Julien Palard in bpo-31639(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29654

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28707

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31639


File: python.info,  Node: idlelib and IDLE,  Next: importlib<4>,  Prev: http server,  Up: Improved Modules<7>

1.7.5.22 idlelib and IDLE
.........................

Multiple fixes for autocompletion.  (Contributed by Louie Lu in
bpo-15786(1).)

Module Browser (on the File menu, formerly called Class Browser), now
displays nested functions and classes in addition to top-level functions
and classes.  (Contributed by Guilherme Polo, Cheryl Sabella, and Terry
Jan Reedy in bpo-1612262(2).)

The Settings dialog (Options, Configure IDLE) has been partly rewritten
to improve both appearance and function.  (Contributed by Cheryl Sabella
and Terry Jan Reedy in multiple issues.)

The font sample now includes a selection of non-Latin characters so that
users can better see the effect of selecting a particular font.
(Contributed by Terry Jan Reedy in bpo-13802(3).)  The sample can be
edited to include other characters.  (Contributed by Serhiy Storchaka in
bpo-31860(4).)

The IDLE features formerly implemented as extensions have been
reimplemented as normal features.  Their settings have been moved from
the Extensions tab to other dialog tabs.  (Contributed by Charles
Wohlganger and Terry Jan Reedy in bpo-27099(5).)

Editor code context option revised.  Box displays all context lines up
to maxlines.  Clicking on a context line jumps the editor to that line.
Context colors for custom themes is added to Highlights tab of Settings
dialog.  (Contributed by Cheryl Sabella and Terry Jan Reedy in
bpo-33642(6), bpo-33768(7), and bpo-33679(8).)

On Windows, a new API call tells Windows that tk scales for DPI. On
Windows 8.1+ or 10, with DPI compatibility properties of the Python
binary unchanged, and a monitor resolution greater than 96 DPI, this
should make text and lines sharper.  It should otherwise have no effect.
(Contributed by Terry Jan Reedy in bpo-33656(9).)

New in 3.7.1:

Output over N lines (50 by default) is squeezed down to a button.  N can
be changed in the PyShell section of the General page of the Settings
dialog.  Fewer, but possibly extra long, lines can be squeezed by right
clicking on the output.  Squeezed output can be expanded in place by
double-clicking the button or into the clipboard or a separate window by
right-clicking the button.  (Contributed by Tal Einat in
bpo-1529353(10).)

The changes above have been backported to 3.6 maintenance releases.

NEW in 3.7.4:

Add “Run Customized” to the Run menu to run a module with customized
settings.  Any command line arguments entered are added to sys.argv.
They re-appear in the box for the next customized run.  One can also
suppress the normal Shell main module restart.  (Contributed by Cheryl
Sabella, Terry Jan Reedy, and others in bpo-5680(11) and bpo-37627(12).)

New in 3.7.5:

Add optional line numbers for IDLE editor windows.  Windows open without
line numbers unless set otherwise in the General tab of the
configuration dialog.  Line numbers for an existing window are shown and
hidden in the Options menu.  (Contributed by Tal Einat and Saimadhav
Heblikar in bpo-17535(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15786

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1612262

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13802

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31860

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27099

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33642

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33768

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33679

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33656

   (10) https://bugs.python.org/issue?@action=redirect&bpo=1529353

   (11) https://bugs.python.org/issue?@action=redirect&bpo=5680

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37627

   (13) https://bugs.python.org/issue?@action=redirect&bpo=17535


File: python.info,  Node: importlib<4>,  Next: io<4>,  Prev: idlelib and IDLE,  Up: Improved Modules<7>

1.7.5.23 importlib
..................

The *note importlib.abc.ResourceReader: b16. ABC was introduced to
support the loading of resources from packages.  See also *note
importlib.resources: ad8.  (Contributed by Barry Warsaw, Brett Cannon in
bpo-32248(1).)

*note importlib.reload(): 51c. now raises *note ModuleNotFoundError:
b61. if the module lacks a spec.  (Contributed by Garvit Khatri in
bpo-29851(2).)

*note importlib.util.find_spec(): 2cd. now raises *note
ModuleNotFoundError: b61. instead of *note AttributeError: 34e. if the
specified parent module is not a package (i.e.  lacks a ‘__path__’
attribute).  (Contributed by Milan Oberkirch in bpo-30436(3).)

The new *note importlib.util.source_hash(): b62. can be used to compute
the hash of the passed source.  A *note hash-based .pyc file: ae1.
embeds the value returned by this function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32248

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29851

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30436


File: python.info,  Node: io<4>,  Next: ipaddress<3>,  Prev: importlib<4>,  Up: Improved Modules<7>

1.7.5.24 io
...........

The new *note TextIOWrapper.reconfigure(): b64. method can be used to
reconfigure the text stream with the new settings.  (Contributed by
Antoine Pitrou in bpo-30526(1) and INADA Naoki in bpo-15216(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30526

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15216


File: python.info,  Node: ipaddress<3>,  Next: itertools<5>,  Prev: io<4>,  Up: Improved Modules<7>

1.7.5.25 ipaddress
..................

The new ‘subnet_of()’ and ‘supernet_of()’ methods of *note
ipaddress.IPv6Network: 1ff. and *note ipaddress.IPv4Network: 1fe. can be
used for network containment tests.  (Contributed by Michel Albert and
Cheryl Sabella in bpo-20825(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20825


File: python.info,  Node: itertools<5>,  Next: locale<4>,  Prev: ipaddress<3>,  Up: Improved Modules<7>

1.7.5.26 itertools
..................

*note itertools.islice(): b67. now accepts *note integer-like objects:
720. as start, stop, and slice arguments.  (Contributed by Will Roberts
in bpo-30537(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30537


File: python.info,  Node: locale<4>,  Next: logging<3>,  Prev: itertools<5>,  Up: Improved Modules<7>

1.7.5.27 locale
...............

The new 'monetary' argument to *note locale.format_string(): 522. can be
used to make the conversion use monetary thousands separators and
grouping strings.  (Contributed by Garvit in bpo-10379(1).)

The *note locale.getpreferredencoding(): 53d. function now always
returns ‘'UTF-8'’ on Android or when in the *note forced UTF-8 mode:
ae0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10379


File: python.info,  Node: logging<3>,  Next: math<6>,  Prev: locale<4>,  Up: Improved Modules<7>

1.7.5.28 logging
................

*note Logger: b6a. instances can now be pickled.  (Contributed by Vinay
Sajip in bpo-30520(1).)

The new *note StreamHandler.setStream(): b6b. method can be used to
replace the logger stream after handler creation.  (Contributed by Vinay
Sajip in bpo-30522(2).)

It is now possible to specify keyword arguments to handler constructors
in configuration passed to *note logging.config.fileConfig(): b6c.
(Contributed by Preston Landers in bpo-31080(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30520

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30522

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31080


File: python.info,  Node: math<6>,  Next: mimetypes<2>,  Prev: logging<3>,  Up: Improved Modules<7>

1.7.5.29 math
.............

The new *note math.remainder(): b6e. function implements the IEEE
754-style remainder operation.  (Contributed by Mark Dickinson in
bpo-29962(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29962


File: python.info,  Node: mimetypes<2>,  Next: msilib,  Prev: math<6>,  Up: Improved Modules<7>

1.7.5.30 mimetypes
..................

The MIME type of .bmp has been changed from ‘'image/x-ms-bmp'’ to
‘'image/bmp'’.  (Contributed by Nitish Chandra in bpo-22589(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22589


File: python.info,  Node: msilib,  Next: multiprocessing<4>,  Prev: mimetypes<2>,  Up: Improved Modules<7>

1.7.5.31 msilib
...............

The new ‘Database.Close()’ method can be used to close the MSI database.
(Contributed by Berker Peksag in bpo-20486(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20486


File: python.info,  Node: multiprocessing<4>,  Next: os<7>,  Prev: msilib,  Up: Improved Modules<7>

1.7.5.32 multiprocessing
........................

The new *note Process.close(): b72. method explicitly closes the process
object and releases all resources associated with it.  *note ValueError:
202. is raised if the underlying process is still running.  (Contributed
by Antoine Pitrou in bpo-30596(1).)

The new *note Process.kill(): b73. method can be used to terminate the
process using the *note SIGKILL: b74. signal on Unix.  (Contributed by
Vitor Pereira in bpo-30794(2).)

Non-daemonic threads created by *note Process: b75. are now joined on
process exit.  (Contributed by Antoine Pitrou in bpo-18966(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30596

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30794

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18966


File: python.info,  Node: os<7>,  Next: pathlib<8>,  Prev: multiprocessing<4>,  Up: Improved Modules<7>

1.7.5.33 os
...........

*note os.fwalk(): b77. now accepts the 'path' argument as *note bytes:
1c2.  (Contributed by Serhiy Storchaka in bpo-28682(1).)

*note os.scandir(): a6d. gained support for *note file descriptors: b78.
(Contributed by Serhiy Storchaka in bpo-25996(2).)

The new *note register_at_fork(): 300. function allows registering
Python callbacks to be executed at process fork.  (Contributed by
Antoine Pitrou in bpo-16500(3).)

Added *note os.preadv(): b79. (combine the functionality of *note
os.readv(): b7a. and *note os.pread(): b7b.) and *note os.pwritev():
b7c. functions (combine the functionality of *note os.writev(): b7d. and
*note os.pwrite(): b7e.).  (Contributed by Pablo Galindo in
bpo-31368(4).)

The mode argument of *note os.makedirs(): 21e. no longer affects the
file permission bits of newly created intermediate-level directories.
(Contributed by Serhiy Storchaka in bpo-19930(5).)

*note os.dup2(): b7f. now returns the new file descriptor.  Previously,
‘None’ was always returned.  (Contributed by Benjamin Peterson in
bpo-32441(6).)

The structure returned by *note os.stat(): 4a3. now contains the *note
st_fstype: b80. attribute on Solaris and its derivatives.  (Contributed
by Jesús Cea Avión in bpo-32659(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28682

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25996

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16500

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31368

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19930

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32441

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32659


File: python.info,  Node: pathlib<8>,  Next: pdb<4>,  Prev: os<7>,  Up: Improved Modules<7>

1.7.5.34 pathlib
................

The new *note Path.is_mount(): a24. method is now available on POSIX
systems and can be used to determine whether a path is a mount point.
(Contributed by Cooper Ry Lees in bpo-30897(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30897


File: python.info,  Node: pdb<4>,  Next: py_compile<3>,  Prev: pathlib<8>,  Up: Improved Modules<7>

1.7.5.35 pdb
............

*note pdb.set_trace(): 235. now takes an optional 'header' keyword-only
argument.  If given, it is printed to the console just before debugging
begins.  (Contributed by Barry Warsaw in bpo-31389(1).)

*note pdb: a5. command line now accepts ‘-m module_name’ as an
alternative to script file.  (Contributed by Mario Corchero in
bpo-32206(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31389

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32206


File: python.info,  Node: py_compile<3>,  Next: pydoc<2>,  Prev: pdb<4>,  Up: Improved Modules<7>

1.7.5.36 py_compile
...................

*note py_compile.compile(): a32. – and by extension, *note compileall:
20. – now respects the ‘SOURCE_DATE_EPOCH’ environment variable by
unconditionally creating ‘.pyc’ files for hash-based validation.  This
allows for guaranteeing reproducible builds(1) of ‘.pyc’ files when they
are created eagerly.  (Contributed by Bernhard M. Wiedemann in
bpo-29708(2).)

   ---------- Footnotes ----------

   (1) https://reproducible-builds.org/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29708


File: python.info,  Node: pydoc<2>,  Next: queue<2>,  Prev: py_compile<3>,  Up: Improved Modules<7>

1.7.5.37 pydoc
..............

The pydoc server can now bind to an arbitrary hostname specified by the
new ‘-n’ command-line argument.  (Contributed by Feanil Patel in
bpo-31128(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31128


File: python.info,  Node: queue<2>,  Next: re<4>,  Prev: pydoc<2>,  Up: Improved Modules<7>

1.7.5.38 queue
..............

The new *note SimpleQueue: b86. class is an unbounded FIFO queue.
(Contributed by Antoine Pitrou in bpo-14976(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14976


File: python.info,  Node: re<4>,  Next: signal<2>,  Prev: queue<2>,  Up: Improved Modules<7>

1.7.5.39 re
...........

The flags *note re.ASCII: 62f, *note re.LOCALE: b88. and *note
re.UNICODE: b89. can be set within the scope of a group.  (Contributed
by Serhiy Storchaka in bpo-31690(1).)

*note re.split(): 2a2. now supports splitting on a pattern like ‘r'\b'’,
‘'^$'’ or ‘(?=-)’ that matches an empty string.  (Contributed by Serhiy
Storchaka in bpo-25054(2).)

Regular expressions compiled with the *note re.LOCALE: b88. flag no
longer depend on the locale at compile time.  Locale settings are
applied only when the compiled regular expression is used.  (Contributed
by Serhiy Storchaka in bpo-30215(3).)

*note FutureWarning: 418. is now emitted if a regular expression
contains character set constructs that will change semantically in the
future, such as nested sets and set operations.  (Contributed by Serhiy
Storchaka in bpo-30349(4).)

Compiled regular expression and match objects can now be copied using
*note copy.copy(): 537. and *note copy.deepcopy(): b8a.  (Contributed by
Serhiy Storchaka in bpo-10076(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31690

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25054

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30215

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30349

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10076


File: python.info,  Node: signal<2>,  Next: socket<5>,  Prev: re<4>,  Up: Improved Modules<7>

1.7.5.40 signal
...............

The new 'warn_on_full_buffer' argument to the *note
signal.set_wakeup_fd(): b8c. function makes it possible to specify
whether Python prints a warning on stderr when the wakeup buffer
overflows.  (Contributed by Nathaniel J. Smith in bpo-30050(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30050


File: python.info,  Node: socket<5>,  Next: socketserver,  Prev: signal<2>,  Up: Improved Modules<7>

1.7.5.41 socket
...............

The new *note socket.getblocking(): b8e. method returns ‘True’ if the
socket is in blocking mode and ‘False’ otherwise.  (Contributed by Yury
Selivanov in bpo-32373(1).)

The new *note socket.close(): b8f. function closes the passed socket
file descriptor.  This function should be used instead of *note
os.close(): b90. for better compatibility across platforms.
(Contributed by Christian Heimes in bpo-32454(2).)

The *note socket: cc. module now exposes the *note
socket.TCP_CONGESTION: b91. (Linux 2.6.13), *note
socket.TCP_USER_TIMEOUT: b91. (Linux 2.6.37), and *note
socket.TCP_NOTSENT_LOWAT: b91. (Linux 3.12) constants.  (Contributed by
Omar Sandoval in bpo-26273(3) and Nathaniel J. Smith in bpo-29728(4).)

Support for *note socket.AF_VSOCK: b92. sockets has been added to allow
communication between virtual machines and their hosts.  (Contributed by
Cathy Avery in bpo-27584(5).)

Sockets now auto-detect family, type and protocol from file descriptor
by default.  (Contributed by Christian Heimes in bpo-28134(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32373

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32454

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26273

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29728

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27584

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28134


File: python.info,  Node: socketserver,  Next: sqlite3<6>,  Prev: socket<5>,  Up: Improved Modules<7>

1.7.5.42 socketserver
.....................

*note socketserver.ThreadingMixIn.server_close: b94. now waits until all
non-daemon threads complete.  ‘socketserver.ForkingMixIn.server_close’
now waits until all child processes complete.

Add a new *note socketserver.ForkingMixIn.block_on_close: b95. class
attribute to *note socketserver.ForkingMixIn: b96. and *note
socketserver.ThreadingMixIn: b5e. classes.  Set the class attribute to
‘False’ to get the pre-3.7 behaviour.


File: python.info,  Node: sqlite3<6>,  Next: ssl<5>,  Prev: socketserver,  Up: Improved Modules<7>

1.7.5.43 sqlite3
................

*note sqlite3.Connection: 245. now exposes the *note backup(): b98.
method when the underlying SQLite library is at version 3.6.11 or
higher.  (Contributed by Lele Gaifax in bpo-27645(1).)

The 'database' argument of *note sqlite3.connect(): 2a8. now accepts any
*note path-like object: 2a0, instead of just a string.  (Contributed by
Anders Lorentsen in bpo-31843(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27645

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31843


File: python.info,  Node: ssl<5>,  Next: string<2>,  Prev: sqlite3<6>,  Up: Improved Modules<7>

1.7.5.44 ssl
............

The *note ssl: d0. module now uses OpenSSL’s builtin API instead of
‘match_hostname()’ to check a host name or an IP address.  Values are
validated during TLS handshake.  Any certificate validation error
including failing the host name check now raises *note
SSLCertVerificationError: b9a. and aborts the handshake with a proper
TLS Alert message.  The new exception contains additional information.
Host name validation can be customized with *note
SSLContext.hostname_checks_common_name: b9b.  (Contributed by Christian
Heimes in bpo-31399(1).)

     Note: The improved host name check requires a 'libssl'
     implementation compatible with OpenSSL 1.0.2 or 1.1.  Consequently,
     OpenSSL 0.9.8 and 1.0.1 are no longer supported (see *note Platform
     Support Removals: b9c. for more details).  The ssl module is mostly
     compatible with LibreSSL 2.7.2 and newer.

The ‘ssl’ module no longer sends IP addresses in SNI TLS extension.
(Contributed by Christian Heimes in bpo-32185(2).)

‘match_hostname()’ no longer supports partial wildcards like
‘www*.example.org’.  (Contributed by Mandeep Singh in bpo-23033(3) and
Christian Heimes in bpo-31399(4).)

The default cipher suite selection of the ‘ssl’ module now uses a
blacklist approach rather than a hard-coded whitelist.  Python no longer
re-enables ciphers that have been blocked by OpenSSL security updates.
Default cipher suite selection can be configured at compile time.
(Contributed by Christian Heimes in bpo-31429(5).)

Validation of server certificates containing internationalized domain
names (IDNs) is now supported.  As part of this change, the *note
SSLSocket.server_hostname: b9d. attribute now stores the expected
hostname in A-label form (‘"xn--pythn-mua.org"’), rather than the
U-label form (‘"pythön.org"’).  (Contributed by Nathaniel J. Smith and
Christian Heimes in bpo-28414(6).)

The ‘ssl’ module has preliminary and experimental support for TLS 1.3
and OpenSSL 1.1.1.  At the time of Python 3.7.0 release, OpenSSL 1.1.1
is still under development and TLS 1.3 hasn’t been finalized yet.  The
TLS 1.3 handshake and protocol behaves slightly differently than TLS 1.2
and earlier, see *note TLS 1.3: b9e.  (Contributed by Christian Heimes
in bpo-32947(7), bpo-20995(8), bpo-29136(9), bpo-30622(10) and
bpo-33618(11))

*note SSLSocket: 8f3. and *note SSLObject: b9f. no longer have a public
constructor.  Direct instantiation was never a documented and supported
feature.  Instances must be created with *note SSLContext: 294. methods
*note wrap_socket(): 528. and *note wrap_bio(): ba0.  (Contributed by
Christian Heimes in bpo-32951(12))

OpenSSL 1.1 APIs for setting the minimum and maximum TLS protocol
version are available as *note SSLContext.minimum_version: 877. and
*note SSLContext.maximum_version: 878.  Supported protocols are
indicated by several new flags, such as *note HAS_TLSv1_1: ba1.
(Contributed by Christian Heimes in bpo-32609(13).)

Added *note ssl.SSLContext.post_handshake_auth: a3e. to enable and *note
ssl.SSLSocket.verify_client_post_handshake(): a3f. to initiate TLS 1.3
post-handshake authentication.  (Contributed by Christian Heimes in
gh-78851(14).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31399

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32185

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23033

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31399

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31429

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28414

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32947

   (8) https://bugs.python.org/issue?@action=redirect&bpo=20995

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29136

   (10) https://bugs.python.org/issue?@action=redirect&bpo=30622

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33618

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32951

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32609

   (14) https://github.com/python/cpython/issues/78851


File: python.info,  Node: string<2>,  Next: subprocess<2>,  Prev: ssl<5>,  Up: Improved Modules<7>

1.7.5.45 string
...............

*note string.Template: 68a. now lets you to optionally modify the
regular expression pattern for braced placeholders and non-braced
placeholders separately.  (Contributed by Barry Warsaw in
bpo-1198569(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1198569


File: python.info,  Node: subprocess<2>,  Next: sys<8>,  Prev: string<2>,  Up: Improved Modules<7>

1.7.5.46 subprocess
...................

The *note subprocess.run(): ba4. function accepts the new
'capture_output' keyword argument.  When true, stdout and stderr will be
captured.  This is equivalent to passing *note subprocess.PIPE: ba5. as
'stdout' and 'stderr' arguments.  (Contributed by Bo Bayles in
bpo-32102(1).)

The ‘subprocess.run’ function and the *note subprocess.Popen: 199.
constructor now accept the 'text' keyword argument as an alias to
'universal_newlines'.  (Contributed by Andrew Clegg in bpo-31756(2).)

On Windows the default for 'close_fds' was changed from ‘False’ to
‘True’ when redirecting the standard handles.  It’s now possible to set
'close_fds' to true when redirecting the standard handles.  See *note
subprocess.Popen: 199.  This means that 'close_fds' now defaults to
‘True’ on all supported platforms.  (Contributed by Segev Finer in
bpo-19764(3).)

The subprocess module is now more graceful when handling *note
KeyboardInterrupt: 9dc. during *note subprocess.call(): ba6, *note
subprocess.run(): ba4, or in a *note Popen: 199. context manager.  It
now waits a short amount of time for the child to exit, before
continuing the handling of the ‘KeyboardInterrupt’ exception.
(Contributed by Gregory P. Smith in bpo-25942(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32102

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31756

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19764

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25942


File: python.info,  Node: sys<8>,  Next: time<5>,  Prev: subprocess<2>,  Up: Improved Modules<7>

1.7.5.47 sys
............

The new *note sys.breakpointhook(): af0. hook function is called by the
built-in *note breakpoint(): 234.  (Contributed by Barry Warsaw in
bpo-31353(1).)

On Android, the new *note sys.getandroidapilevel(): ba8. returns the
build-time Android API version.  (Contributed by Victor Stinner in
bpo-28740(2).)

The new *note sys.get_coroutine_origin_tracking_depth(): ba9. function
returns the current coroutine origin tracking depth, as set by the new
*note sys.set_coroutine_origin_tracking_depth(): baa.  *note asyncio: a.
has been converted to use this new API instead of the deprecated
‘sys.set_coroutine_wrapper()’.  (Contributed by Nathaniel J. Smith in
bpo-32591(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31353

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28740

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32591


File: python.info,  Node: time<5>,  Next: tkinter<5>,  Prev: sys<8>,  Up: Improved Modules<7>

1.7.5.48 time
.............

PEP 564(1) adds six new functions with nanosecond resolution to the
*note time: ee. module:

   * *note time.clock_gettime_ns(): afa.

   * *note time.clock_settime_ns(): afb.

   * *note time.monotonic_ns(): afc.

   * *note time.perf_counter_ns(): afd.

   * *note time.process_time_ns(): afe.

   * *note time.time_ns(): aff.

New clock identifiers have been added:

   * *note time.CLOCK_BOOTTIME: bac. (Linux): Identical to *note
     time.CLOCK_MONOTONIC: 69c, except it also includes any time that
     the system is suspended.

   * *note time.CLOCK_PROF: bad. (FreeBSD, NetBSD and OpenBSD):
     High-resolution per-process CPU timer.

   * *note time.CLOCK_UPTIME: bae. (FreeBSD, OpenBSD): Time whose
     absolute value is the time the system has been running and not
     suspended, providing accurate uptime measurement.

The new *note time.thread_time(): 940. and *note time.thread_time_ns():
baf. functions can be used to get per-thread CPU time measurements.
(Contributed by Antoine Pitrou in bpo-32025(2).)

The new *note time.pthread_getcpuclockid(): bb0. function returns the
clock ID of the thread-specific CPU-time clock.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0564/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32025


File: python.info,  Node: tkinter<5>,  Next: tracemalloc<2>,  Prev: time<5>,  Up: Improved Modules<7>

1.7.5.49 tkinter
................

The new *note tkinter.ttk.Spinbox: bb2. class is now available.
(Contributed by Alan Moore in bpo-32585(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32585


File: python.info,  Node: tracemalloc<2>,  Next: types<4>,  Prev: tkinter<5>,  Up: Improved Modules<7>

1.7.5.50 tracemalloc
....................

*note tracemalloc.Traceback: bb4. behaves more like regular tracebacks,
sorting the frames from oldest to most recent.  *note
Traceback.format(): bb5. now accepts negative 'limit', truncating the
result to the ‘abs(limit)’ oldest frames.  To get the old behaviour, use
the new 'most_recent_first' argument to ‘Traceback.format()’.
(Contributed by Jesse Bakker in bpo-32121(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32121


File: python.info,  Node: types<4>,  Next: unicodedata<6>,  Prev: tracemalloc<2>,  Up: Improved Modules<7>

1.7.5.51 types
..............

The new *note WrapperDescriptorType: bb7, *note MethodWrapperType: 64e,
*note MethodDescriptorType: bb8, and *note ClassMethodDescriptorType:
bb9. classes are now available.  (Contributed by Manuel Krebber and
Guido van Rossum in bpo-29377(1), and Serhiy Storchaka in bpo-32265(2).)

The new *note types.resolve_bases(): bba. function resolves MRO entries
dynamically as specified by PEP 560(3).  (Contributed by Ivan Levkivskyi
in bpo-32717(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29377

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32265

   (3) https://peps.python.org/pep-0560/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32717


File: python.info,  Node: unicodedata<6>,  Next: unittest<7>,  Prev: types<4>,  Up: Improved Modules<7>

1.7.5.52 unicodedata
....................

The internal *note unicodedata: 105. database has been upgraded to use
Unicode 11(1).  (Contributed by Benjamin Peterson.)

   ---------- Footnotes ----------

   (1) https://www.unicode.org/versions/Unicode11.0.0/


File: python.info,  Node: unittest<7>,  Next: unittest mock,  Prev: unicodedata<6>,  Up: Improved Modules<7>

1.7.5.53 unittest
.................

The new ‘-k’ command-line option allows filtering tests by a name
substring or a Unix shell-like pattern.  For example, ‘python -m
unittest -k foo’ runs ‘foo_tests.SomeTest.test_something’,
‘bar_tests.SomeTest.test_foo’, but not
‘bar_tests.FooTest.test_something’.  (Contributed by Jonas Haag in
bpo-32071(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32071


File: python.info,  Node: unittest mock,  Next: urllib parse<5>,  Prev: unittest<7>,  Up: Improved Modules<7>

1.7.5.54 unittest.mock
......................

The *note sentinel: bbe. attributes now preserve their identity when
they are *note copied: 25. or *note pickled: a6.  (Contributed by Serhiy
Storchaka in bpo-20804(1).)

The new *note seal(): bbf. function allows sealing *note Mock: a58.
instances, which will disallow further creation of attribute mocks.  The
seal is applied recursively to all attributes that are themselves mocks.
(Contributed by Mario Corchero in bpo-30541(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20804

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30541


File: python.info,  Node: urllib parse<5>,  Next: uu,  Prev: unittest mock,  Up: Improved Modules<7>

1.7.5.55 urllib.parse
.....................

*note urllib.parse.quote(): bc1. has been updated from RFC 2396(1) to
RFC 3986(2), adding ‘~’ to the set of characters that are never quoted
by default.  (Contributed by Christian Theune and Ratnadeep Debnath in
bpo-16285(3).)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2396.html

   (2) https://datatracker.ietf.org/doc/html/rfc3986.html

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16285


File: python.info,  Node: uu,  Next: uuid<2>,  Prev: urllib parse<5>,  Up: Improved Modules<7>

1.7.5.56 uu
...........

The ‘uu.encode()’ function now accepts an optional 'backtick' keyword
argument.  When it’s true, zeros are represented by ‘'`'’ instead of
spaces.  (Contributed by Xiang Zhang in bpo-30103(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30103


File: python.info,  Node: uuid<2>,  Next: warnings<3>,  Prev: uu,  Up: Improved Modules<7>

1.7.5.57 uuid
.............

The new *note UUID.is_safe: bc4. attribute relays information from the
platform about whether generated UUIDs are generated with a
multiprocessing-safe method.  (Contributed by Barry Warsaw in
bpo-22807(1).)

*note uuid.getnode(): bc5. now prefers universally administered MAC
addresses over locally administered MAC addresses.  This makes a better
guarantee for global uniqueness of UUIDs returned from *note
uuid.uuid1(): bc6.  If only locally administered MAC addresses are
available, the first such one found is returned.  (Contributed by Barry
Warsaw in bpo-32107(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22807

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32107


File: python.info,  Node: warnings<3>,  Next: xml<5>,  Prev: uuid<2>,  Up: Improved Modules<7>

1.7.5.58 warnings
.................

The initialization of the default warnings filters has changed as
follows:

   * warnings enabled via command line options (including those for
     *note -b: 5e6. and the new CPython-specific *note -X: 176. ‘dev’
     option) are always passed to the warnings machinery via the *note
     sys.warnoptions: 3b3. attribute.

   * warnings filters enabled via the command line or the environment
     now have the following order of precedence:

        * the ‘BytesWarning’ filter for *note -b: 5e6. (or ‘-bb’)

        * any filters specified with the *note -W: 8d0. option

        * any filters specified with the *note PYTHONWARNINGS: bc8.
          environment variable

        * any other CPython specific filters (e.g.  the ‘default’ filter
          added for the new ‘-X dev’ mode)

        * any implicit filters defined directly by the warnings
          machinery

   * in *note CPython debug builds: 1f9, all warnings are now displayed
     by default (the implicit filter list is empty)

(Contributed by Nick Coghlan and Victor Stinner in bpo-20361(1),
bpo-32043(2), and bpo-32230(3).)

Deprecation warnings are once again shown by default in single-file
scripts and at the interactive prompt.  See *note PEP 565; Show
DeprecationWarning in __main__: ae3. for details.  (Contributed by Nick
Coghlan in bpo-31975(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20361

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32043

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32230

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31975


File: python.info,  Node: xml<5>,  Next: xml etree,  Prev: warnings<3>,  Up: Improved Modules<7>

1.7.5.59 xml
............

As mitigation against DTD and external entity retrieval, the *note
xml.dom.minidom: 122. and *note xml.sax: 129. modules no longer process
external entities by default.  (Contributed by Christian Heimes in
gh-61441(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/61441


File: python.info,  Node: xml etree,  Next: xmlrpc server,  Prev: xml<5>,  Up: Improved Modules<7>

1.7.5.60 xml.etree
..................

*note ElementPath: bcb. predicates in the ‘find()’ methods can now
compare text of the current node with ‘[. = "text"]’, not only text in
children.  Predicates also allow adding spaces for better readability.
(Contributed by Stefan Behnel in bpo-31648(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31648


File: python.info,  Node: xmlrpc server,  Next: zipapp,  Prev: xml etree,  Up: Improved Modules<7>

1.7.5.61 xmlrpc.server
......................

‘SimpleXMLRPCDispatcher.register_function()’ can now be used as a
decorator.  (Contributed by Xiang Zhang in bpo-7769(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7769


File: python.info,  Node: zipapp,  Next: zipfile<2>,  Prev: xmlrpc server,  Up: Improved Modules<7>

1.7.5.62 zipapp
...............

Function *note create_archive(): bce. now accepts an optional 'filter'
argument to allow the user to select which files should be included in
the archive.  (Contributed by Irmen de Jong in bpo-31072(1).)

Function *note create_archive(): bce. now accepts an optional
'compressed' argument to generate a compressed archive.  A command line
option ‘--compress’ has also been added to support compression.
(Contributed by Zhiming Wang in bpo-31638(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31072

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31638


File: python.info,  Node: zipfile<2>,  Prev: zipapp,  Up: Improved Modules<7>

1.7.5.63 zipfile
................

*note ZipFile: 6c7. now accepts the new 'compresslevel' parameter to
control the compression level.  (Contributed by Bo Bayles in
bpo-21417(1).)

Subdirectories in archives created by ‘ZipFile’ are now stored in
alphabetical order.  (Contributed by Bernhard M. Wiedemann in
bpo-30693(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21417

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30693


File: python.info,  Node: C API Changes<6>,  Next: Build Changes<6>,  Prev: Improved Modules<7>,  Up: What’s New In Python 3 7

1.7.6 C API Changes
-------------------

A new API for thread-local storage has been implemented.  See *note PEP
539; New C API for Thread-Local Storage: ae4. for an overview and *note
Thread Specific Storage (TSS) API: af4. for a complete reference.
(Contributed by Masayuki Yamamoto in bpo-25658(1).)

The new *note context variables: ad6. functionality exposes a number of
*note new C APIs: b11.

The new *note PyImport_GetModule(): bd1. function returns the previously
imported module with the given name.  (Contributed by Eric Snow in
bpo-28411(2).)

The new *note Py_RETURN_RICHCOMPARE: bd2. macro eases writing rich
comparison functions.  (Contributed by Petr Victorin in bpo-23699(3).)

The new *note Py_UNREACHABLE: bd3. macro can be used to mark unreachable
code paths.  (Contributed by Barry Warsaw in bpo-31338(4).)

The *note tracemalloc: ff. now exposes a C API through the new *note
PyTraceMalloc_Track(): bd4. and *note PyTraceMalloc_Untrack(): bd5.
functions.  (Contributed by Victor Stinner in bpo-30054(5).)

The new *note import__find__load__start: bd6. and *note
import__find__load__done: bd6. static markers can be used to trace
module imports.  (Contributed by Christian Heimes in bpo-31574(6).)

The fields ‘name’ and ‘doc’ of structures *note PyMemberDef: 552, *note
PyGetSetDef: bd7, *note PyStructSequence_Field: bd8, *note
PyStructSequence_Desc: bd9, and ‘wrapperbase’ are now of type ‘const
char *’ rather of ‘char *’.  (Contributed by Serhiy Storchaka in
bpo-28761(7).)

The result of *note PyUnicode_AsUTF8AndSize(): 8a0. and *note
PyUnicode_AsUTF8(): bda. is now of type ‘const char *’ rather of ‘char
*’.  (Contributed by Serhiy Storchaka in bpo-28769(8).)

The result of *note PyMapping_Keys(): bdb, *note PyMapping_Values():
bdc. and *note PyMapping_Items(): bdd. is now always a list, rather than
a list or a tuple.  (Contributed by Oren Milman in bpo-28280(9).)

Added functions *note PySlice_Unpack(): 400. and *note
PySlice_AdjustIndices(): 401.  (Contributed by Serhiy Storchaka in
bpo-27867(10).)

*note PyOS_AfterFork(): 3fd. is deprecated in favour of the new
functions *note PyOS_BeforeFork(): bde, *note PyOS_AfterFork_Parent():
bdf. and *note PyOS_AfterFork_Child(): 3fe.  (Contributed by Antoine
Pitrou in bpo-16500(11).)

The ‘PyExc_RecursionErrorInst’ singleton that was part of the public API
has been removed as its members being never cleared may cause a segfault
during finalization of the interpreter.  Contributed by Xavier de Gaye
in bpo-22898(12) and bpo-30697(13).

Added C API support for timezones with timezone constructors *note
PyTimeZone_FromOffset(): be0. and *note PyTimeZone_FromOffsetAndName():
be1, and access to the UTC singleton with *note PyDateTime_TimeZone_UTC:
be2.  Contributed by Paul Ganssle in bpo-10381(14).

The type of results of ‘PyThread_start_new_thread()’ and
‘PyThread_get_thread_ident()’, and the 'id' parameter of *note
PyThreadState_SetAsyncExc(): be3. changed from long to unsigned long.
(Contributed by Serhiy Storchaka in bpo-6532(15).)

*note PyUnicode_AsWideCharString(): 8c4. now raises a *note ValueError:
202. if the second argument is ‘NULL’ and the wchar_t* string contains
null characters.  (Contributed by Serhiy Storchaka in bpo-30708(16).)

Changes to the startup sequence and the management of dynamic memory
allocators mean that the long documented requirement to call *note
Py_Initialize(): 8b4. before calling most C API functions is now relied
on more heavily, and failing to abide by it may lead to segfaults in
embedding applications.  See the *note Porting to Python 3.7: ae7.
section in this document and the *note Before Python Initialization:
be4. section in the C API documentation for more details.

The new *note PyInterpreterState_GetID(): be5. returns the unique ID for
a given interpreter.  (Contributed by Eric Snow in bpo-29102(17).)

*note Py_DecodeLocale(): be6, *note Py_EncodeLocale(): be7. now use the
UTF-8 encoding when the *note UTF-8 mode: ae0. is enabled.  (Contributed
by Victor Stinner in bpo-29240(18).)

*note PyUnicode_DecodeLocaleAndSize(): be8. and *note
PyUnicode_EncodeLocale(): be9. now use the current locale encoding for
‘surrogateescape’ error handler.  (Contributed by Victor Stinner in
bpo-29240(19).)

The 'start' and 'end' parameters of *note PyUnicode_FindChar(): 8c1. are
now adjusted to behave like string slices.  (Contributed by Xiang Zhang
in bpo-28822(20).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25658

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28411

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23699

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31338

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30054

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31574

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28761

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28769

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28280

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27867

   (11) https://bugs.python.org/issue?@action=redirect&bpo=16500

   (12) https://bugs.python.org/issue?@action=redirect&bpo=22898

   (13) https://bugs.python.org/issue?@action=redirect&bpo=30697

   (14) https://bugs.python.org/issue?@action=redirect&bpo=10381

   (15) https://bugs.python.org/issue?@action=redirect&bpo=6532

   (16) https://bugs.python.org/issue?@action=redirect&bpo=30708

   (17) https://bugs.python.org/issue?@action=redirect&bpo=29102

   (18) https://bugs.python.org/issue?@action=redirect&bpo=29240

   (19) https://bugs.python.org/issue?@action=redirect&bpo=29240

   (20) https://bugs.python.org/issue?@action=redirect&bpo=28822


File: python.info,  Node: Build Changes<6>,  Next: Optimizations<7>,  Prev: C API Changes<6>,  Up: What’s New In Python 3 7

1.7.7 Build Changes
-------------------

Support for building ‘--without-threads’ has been removed.  The *note
threading: ed. module is now always available.  (Contributed by Antoine
Pitrou in bpo-31370(1).).

A full copy of libffi is no longer bundled for use when building the
*note _ctypes: 2a. module on non-OSX UNIX platforms.  An installed copy
of libffi is now required when building ‘_ctypes’ on such platforms.
(Contributed by Zachary Ware in bpo-27979(2).)

The Windows build process no longer depends on Subversion to pull in
external sources, a Python script is used to download zipfiles from
GitHub instead.  If Python 3.6 is not found on the system (via ‘py
-3.6’), NuGet is used to download a copy of 32-bit Python for this
purpose.  (Contributed by Zachary Ware in bpo-30450(3).)

The *note ssl: d0. module requires OpenSSL 1.0.2 or 1.1 compatible
libssl.  OpenSSL 1.0.1 has reached end of lifetime on 2016-12-31 and is
no longer supported.  LibreSSL is temporarily not supported as well.
LibreSSL releases up to version 2.6.4 are missing required OpenSSL 1.0.2
APIs.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31370

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27979

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30450


File: python.info,  Node: Optimizations<7>,  Next: Other CPython Implementation Changes<2>,  Prev: Build Changes<6>,  Up: What’s New In Python 3 7

1.7.8 Optimizations
-------------------

The overhead of calling many methods of various standard library classes
implemented in C has been significantly reduced by porting more code to
use the ‘METH_FASTCALL’ convention.  (Contributed by Victor Stinner in
bpo-29300(1), bpo-29507(2), bpo-29452(3), and bpo-29286(4).)

Various optimizations have reduced Python startup time by 10% on Linux
and up to 30% on macOS. (Contributed by Victor Stinner, INADA Naoki in
bpo-29585(5), and Ivan Levkivskyi in bpo-31333(6).)

Method calls are now up to 20% faster due to the bytecode changes which
avoid creating bound method instances.  (Contributed by Yury Selivanov
and INADA Naoki in bpo-26110(7).)  The *note asyncio: a. module received
a number of notable optimizations for commonly used functions:

   * The *note asyncio.get_event_loop(): 2c2. function has been
     reimplemented in C to make it up to 15 times faster.  (Contributed
     by Yury Selivanov in bpo-32296(8).)

   * *note asyncio.Future: bec. callback management has been optimized.
     (Contributed by Yury Selivanov in bpo-32348(9).)

   * *note asyncio.gather(): 600. is now up to 15% faster.  (Contributed
     by Yury Selivanov in bpo-32355(10).)

   * *note asyncio.sleep(): a7e. is now up to 2 times faster when the
     'delay' argument is zero or negative.  (Contributed by Andrew
     Svetlov in bpo-32351(11).)

   * The performance overhead of asyncio debug mode has been reduced.
     (Contributed by Antoine Pitrou in bpo-31970(12).)

As a result of *note PEP 560 work: adb, the import time of *note typing:
104. has been reduced by a factor of 7, and many typing operations are
now faster.  (Contributed by Ivan Levkivskyi in bpo-32226(13).)

*note sorted(): bed. and *note list.sort(): bee. have been optimized for
common cases to be up to 40-75% faster.  (Contributed by Elliot
Gorokhovsky in bpo-28685(14).)

*note dict.copy(): bef. is now up to 5.5 times faster.  (Contributed by
Yury Selivanov in bpo-31179(15).)

*note hasattr(): 4d5. and *note getattr(): bf0. are now about 4 times
faster when 'name' is not found and 'obj' does not override *note
object.__getattr__(): 4d6. or *note object.__getattribute__(): bf1.
(Contributed by INADA Naoki in bpo-32544(16).)

Searching for certain Unicode characters (like Ukrainian capital “Є”) in
a string was up to 25 times slower than searching for other characters.
It is now only 3 times slower in the worst case.  (Contributed by Serhiy
Storchaka in bpo-24821(17).)

The *note collections.namedtuple(): 1ca. factory has been reimplemented
to make the creation of named tuples 4 to 6 times faster.  (Contributed
by Jelle Zijlstra with further improvements by INADA Naoki, Serhiy
Storchaka, and Raymond Hettinger in bpo-28638(18).)

*note datetime.date.fromordinal(): bf2. and *note
datetime.date.fromtimestamp(): bf3. are now up to 30% faster in the
common case.  (Contributed by Paul Ganssle in bpo-32403(19).)

The *note os.fwalk(): b77. function is now up to 2 times faster thanks
to the use of *note os.scandir(): a6d.  (Contributed by Serhiy Storchaka
in bpo-25996(20).)

The speed of the *note shutil.rmtree(): 301. function has been improved
by 20–40% thanks to the use of the *note os.scandir(): a6d. function.
(Contributed by Serhiy Storchaka in bpo-28564(21).)

Optimized case-insensitive matching and searching of *note regular
expressions: b9.  Searching some patterns can now be up to 20 times
faster.  (Contributed by Serhiy Storchaka in bpo-30285(22).)

*note re.compile(): bf4. now converts ‘flags’ parameter to int object if
it is ‘RegexFlag’.  It is now as fast as Python 3.5, and faster than
Python 3.6 by about 10% depending on the pattern.  (Contributed by INADA
Naoki in bpo-31671(23).)

The *note modify(): bf5. methods of classes *note
selectors.EpollSelector: bf6, *note selectors.PollSelector: bf7. and
*note selectors.DevpollSelector: bf8. may be around 10% faster under
heavy loads.  (Contributed by Giampaolo Rodola’ in bpo-30014(24))

Constant folding has been moved from the peephole optimizer to the new
AST optimizer, which is able perform optimizations more consistently.
(Contributed by Eugene Toder and INADA Naoki in bpo-29469(25) and
bpo-11549(26).)

Most functions and methods in *note abc: 4. have been rewritten in C.
This makes creation of abstract base classes, and calling *note
isinstance(): 445. and *note issubclass(): 7c5. on them 1.5x faster.
This also reduces Python start-up time by up to 10%.  (Contributed by
Ivan Levkivskyi and INADA Naoki in bpo-31333(27))

Significant speed improvements to alternate constructors for *note
datetime.date: 1cd. and *note datetime.datetime: 1cc. by using fast-path
constructors when not constructing subclasses.  (Contributed by Paul
Ganssle in bpo-32403(28))

The speed of comparison of *note array.array: 1a0. instances has been
improved considerably in certain cases.  It is now from 10x to 70x
faster when comparing arrays holding values of the same integer type.
(Contributed by Adrian Wielgosik in bpo-24700(29).)

The *note math.erf(): bf9. and *note math.erfc(): bfa. functions now use
the (faster) C library implementation on most platforms.  (Contributed
by Serhiy Storchaka in bpo-26121(30).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29300

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29507

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29452

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29286

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29585

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31333

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26110

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32296

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32348

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32355

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32351

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31970

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32226

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28685

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31179

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32544

   (17) https://bugs.python.org/issue?@action=redirect&bpo=24821

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28638

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32403

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25996

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28564

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30285

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31671

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30014

   (25) https://bugs.python.org/issue?@action=redirect&bpo=29469

   (26) https://bugs.python.org/issue?@action=redirect&bpo=11549

   (27) https://bugs.python.org/issue?@action=redirect&bpo=31333

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32403

   (29) https://bugs.python.org/issue?@action=redirect&bpo=24700

   (30) https://bugs.python.org/issue?@action=redirect&bpo=26121


File: python.info,  Node: Other CPython Implementation Changes<2>,  Next: Deprecated Python Behavior,  Prev: Optimizations<7>,  Up: What’s New In Python 3 7

1.7.9 Other CPython Implementation Changes
------------------------------------------

   * Trace hooks may now opt out of receiving the ‘line’ and opt into
     receiving the ‘opcode’ events from the interpreter by setting the
     corresponding new *note f_trace_lines: bfc. and *note
     f_trace_opcodes: bfd. attributes on the frame being traced.
     (Contributed by Nick Coghlan in bpo-31344(1).)

   * Fixed some consistency problems with namespace package module
     attributes.  Namespace module objects now have an ‘__file__’ that
     is set to ‘None’ (previously unset), and their ‘__spec__.origin’ is
     also set to ‘None’ (previously the string ‘"namespace"’).  See
     bpo-32305(2).  Also, the namespace module object’s
     ‘__spec__.loader’ is set to the same value as ‘__loader__’
     (previously, the former was set to ‘None’).  See bpo-32303(3).

   * The *note locals(): 141. dictionary now displays in the lexical
     order that variables were defined.  Previously, the order was
     undefined.  (Contributed by Raymond Hettinger in bpo-32690(4).)

   * The ‘distutils’ ‘upload’ command no longer tries to change CR
     end-of-line characters to CRLF. This fixes a corruption issue with
     sdists that ended with a byte equivalent to CR. (Contributed by Bo
     Bayles in bpo-32304(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31344

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32305

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32303

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32690

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32304


File: python.info,  Node: Deprecated Python Behavior,  Next: Deprecated Python modules functions and methods,  Prev: Other CPython Implementation Changes<2>,  Up: What’s New In Python 3 7

1.7.10 Deprecated Python Behavior
---------------------------------

Yield expressions (both ‘yield’ and ‘yield from’ clauses) are now
deprecated in comprehensions and generator expressions (aside from the
iterable expression in the leftmost ‘for’ clause).  This ensures that
comprehensions always immediately return a container of the appropriate
type (rather than potentially returning a *note generator iterator: bff.
object), while generator expressions won’t attempt to interleave their
implicit output with the output from any explicit yield expressions.  In
Python 3.7, such expressions emit *note DeprecationWarning: 1a5. when
compiled, in Python 3.8 this will be a *note SyntaxError: 18d.
(Contributed by Serhiy Storchaka in bpo-10544(1).)

Returning a subclass of *note complex: 2f8. from *note
object.__complex__(): 5ea. is deprecated and will be an error in future
Python versions.  This makes ‘__complex__()’ consistent with *note
object.__int__(): 71f. and *note object.__float__(): 9d7.  (Contributed
by Serhiy Storchaka in bpo-28894(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10544

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28894


File: python.info,  Node: Deprecated Python modules functions and methods,  Next: Deprecated functions and types of the C API,  Prev: Deprecated Python Behavior,  Up: What’s New In Python 3 7

1.7.11 Deprecated Python modules, functions and methods
-------------------------------------------------------

* Menu:

* aifc::
* asyncio: asyncio<8>.
* collections: collections<3>.
* dbm: dbm<3>.
* enum: enum<6>.
* gettext: gettext<2>.
* importlib: importlib<5>.
* locale: locale<5>.
* macpath::
* threading: threading<5>.
* socket: socket<6>.
* ssl: ssl<6>.
* sunau::
* sys: sys<9>.
* wave::


File: python.info,  Node: aifc,  Next: asyncio<8>,  Up: Deprecated Python modules functions and methods

1.7.11.1 aifc
.............

‘aifc.openfp()’ has been deprecated and will be removed in Python 3.9.
Use ‘aifc.open()’ instead.  (Contributed by Brian Curtin in
bpo-31985(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31985


File: python.info,  Node: asyncio<8>,  Next: collections<3>,  Prev: aifc,  Up: Deprecated Python modules functions and methods

1.7.11.2 asyncio
................

Support for directly ‘await’-ing instances of *note asyncio.Lock: a80.
and other asyncio synchronization primitives has been deprecated.  An
asynchronous context manager must be used in order to acquire and
release the synchronization resource.  (Contributed by Andrew Svetlov in
bpo-32253(1).)

The ‘asyncio.Task.current_task()’ and ‘asyncio.Task.all_tasks()’ methods
have been deprecated.  (Contributed by Andrew Svetlov in bpo-32250(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32253

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32250


File: python.info,  Node: collections<3>,  Next: dbm<3>,  Prev: asyncio<8>,  Up: Deprecated Python modules functions and methods

1.7.11.3 collections
....................

In Python 3.8, the abstract base classes in *note collections.abc: 1e.
will no longer be exposed in the regular *note collections: 1d. module.
This will help create a clearer distinction between the concrete classes
and the abstract base classes.  (Contributed by Serhiy Storchaka in
bpo-25988(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25988


File: python.info,  Node: dbm<3>,  Next: enum<6>,  Prev: collections<3>,  Up: Deprecated Python modules functions and methods

1.7.11.4 dbm
............

*note dbm.dumb: 32. now supports reading read-only files and no longer
writes the index file when it is not changed.  A deprecation warning is
now emitted if the index file is missing and recreated in the ‘'r'’ and
‘'w'’ modes (this will be an error in future Python releases).
(Contributed by Serhiy Storchaka in bpo-28847(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28847


File: python.info,  Node: enum<6>,  Next: gettext<2>,  Prev: dbm<3>,  Up: Deprecated Python modules functions and methods

1.7.11.5 enum
.............

In Python 3.8, attempting to check for non-Enum objects in *note Enum:
633. classes will raise a *note TypeError: 2c3. (e.g.  ‘1 in Color’);
similarly, attempting to check for non-Flag objects in a *note Flag:
626. member will raise ‘TypeError’ (e.g.  ‘1 in Perm.RW’); currently,
both operations return *note False: b4f. instead.  (Contributed by Ethan
Furman in bpo-33217(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33217


File: python.info,  Node: gettext<2>,  Next: importlib<5>,  Prev: enum<6>,  Up: Deprecated Python modules functions and methods

1.7.11.6 gettext
................

Using non-integer value for selecting a plural form in *note gettext:
63. is now deprecated.  It never correctly worked.  (Contributed by
Serhiy Storchaka in bpo-28692(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28692


File: python.info,  Node: importlib<5>,  Next: locale<5>,  Prev: gettext<2>,  Up: Deprecated Python modules functions and methods

1.7.11.7 importlib
..................

Methods ‘MetaPathFinder.find_module()’ (replaced by *note
MetaPathFinder.find_spec(): 86f.) and ‘PathEntryFinder.find_loader()’
(replaced by *note PathEntryFinder.find_spec(): 873.) both deprecated in
Python 3.4 now emit *note DeprecationWarning: 1a5.  (Contributed by
Matthias Bussonnier in bpo-29576(1).)

The *note importlib.abc.ResourceLoader: c08. ABC has been deprecated in
favour of *note importlib.abc.ResourceReader: b16.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29576


File: python.info,  Node: locale<5>,  Next: macpath,  Prev: importlib<5>,  Up: Deprecated Python modules functions and methods

1.7.11.8 locale
...............

‘locale.format()’ has been deprecated, use *note locale.format_string():
522. instead.  (Contributed by Garvit in bpo-10379(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10379


File: python.info,  Node: macpath,  Next: threading<5>,  Prev: locale<5>,  Up: Deprecated Python modules functions and methods

1.7.11.9 macpath
................

The ‘macpath’ is now deprecated and will be removed in Python 3.8.
(Contributed by Chi Hsuan Yen in bpo-9850(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9850


File: python.info,  Node: threading<5>,  Next: socket<6>,  Prev: macpath,  Up: Deprecated Python modules functions and methods

1.7.11.10 threading
...................

‘dummy_threading’ and ‘_dummy_thread’ have been deprecated.  It is no
longer possible to build Python with threading disabled.  Use *note
threading: ed. instead.  (Contributed by Antoine Pitrou in
bpo-31370(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31370


File: python.info,  Node: socket<6>,  Next: ssl<6>,  Prev: threading<5>,  Up: Deprecated Python modules functions and methods

1.7.11.11 socket
................

The silent argument value truncation in *note socket.htons(): 886. and
*note socket.ntohs(): 887. has been deprecated.  In future versions of
Python, if the passed argument is larger than 16 bits, an exception will
be raised.  (Contributed by Oren Milman in bpo-28332(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28332


File: python.info,  Node: ssl<6>,  Next: sunau,  Prev: socket<6>,  Up: Deprecated Python modules functions and methods

1.7.11.12 ssl
.............

‘ssl.wrap_socket()’ is deprecated.  Use *note
ssl.SSLContext.wrap_socket(): 528. instead.  (Contributed by Christian
Heimes in bpo-28124(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28124


File: python.info,  Node: sunau,  Next: sys<9>,  Prev: ssl<6>,  Up: Deprecated Python modules functions and methods

1.7.11.13 sunau
...............

‘sunau.openfp()’ has been deprecated and will be removed in Python 3.9.
Use ‘sunau.open()’ instead.  (Contributed by Brian Curtin in
bpo-31985(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31985


File: python.info,  Node: sys<9>,  Next: wave,  Prev: sunau,  Up: Deprecated Python modules functions and methods

1.7.11.14 sys
.............

Deprecated ‘sys.set_coroutine_wrapper()’ and
‘sys.get_coroutine_wrapper()’.

The undocumented ‘sys.callstats()’ function has been deprecated and will
be removed in a future Python version.  (Contributed by Victor Stinner
in bpo-28799(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28799


File: python.info,  Node: wave,  Prev: sys<9>,  Up: Deprecated Python modules functions and methods

1.7.11.15 wave
..............

‘wave.openfp()’ has been deprecated and will be removed in Python 3.9.
Use *note wave.open(): 955. instead.  (Contributed by Brian Curtin in
bpo-31985(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31985


File: python.info,  Node: Deprecated functions and types of the C API,  Next: Platform Support Removals,  Prev: Deprecated Python modules functions and methods,  Up: What’s New In Python 3 7

1.7.12 Deprecated functions and types of the C API
--------------------------------------------------

Function *note PySlice_GetIndicesEx(): 3ff. is deprecated and replaced
with a macro if ‘Py_LIMITED_API’ is not set or set to a value in the
range between ‘0x03050400’ and ‘0x03060000’ (not inclusive), or is
‘0x03060100’ or higher.  (Contributed by Serhiy Storchaka in
bpo-27867(1).)

*note PyOS_AfterFork(): 3fd. has been deprecated.  Use *note
PyOS_BeforeFork(): bde, *note PyOS_AfterFork_Parent(): bdf. or *note
PyOS_AfterFork_Child(): 3fe. instead.  (Contributed by Antoine Pitrou in
bpo-16500(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27867

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16500


File: python.info,  Node: Platform Support Removals,  Next: API and Feature Removals<2>,  Prev: Deprecated functions and types of the C API,  Up: What’s New In Python 3 7

1.7.13 Platform Support Removals
--------------------------------

   * FreeBSD 9 and older are no longer officially supported.

   * For full Unicode support, including within extension modules, *nix
     platforms are now expected to provide at least one of ‘C.UTF-8’
     (full locale), ‘C.utf8’ (full locale) or ‘UTF-8’ (‘LC_CTYPE’-only
     locale) as an alternative to the legacy ‘ASCII’-based ‘C’ locale.

   * OpenSSL 0.9.8 and 1.0.1 are no longer supported, which means
     building CPython 3.7 with SSL/TLS support on older platforms still
     using these versions requires custom build options that link to a
     more recent version of OpenSSL.

     Notably, this issue affects the Debian 8 (aka “jessie”) and Ubuntu
     14.04 (aka “Trusty”) LTS Linux distributions, as they still use
     OpenSSL 1.0.1 by default.

     Debian 9 (“stretch”) and Ubuntu 16.04 (“xenial”), as well as recent
     releases of other LTS Linux releases (e.g.  RHEL/CentOS 7.5, SLES
     12-SP3), use OpenSSL 1.0.2 or later, and remain supported in the
     default build configuration.

     CPython’s own CI configuration file(1) provides an example of using
     the SSL compatibility testing infrastructure(2) in CPython’s test
     suite to build and link against OpenSSL 1.1.0 rather than an
     outdated system provided OpenSSL.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/blob/v3.7.13/.travis.yml

   (2) 
https://github.com/python/cpython/tree/3.13/Tools/ssl/multissltests.py


File: python.info,  Node: API and Feature Removals<2>,  Next: Module Removals,  Prev: Platform Support Removals,  Up: What’s New In Python 3 7

1.7.14 API and Feature Removals
-------------------------------

The following features and APIs have been removed from Python 3.7:

   * The ‘os.stat_float_times()’ function has been removed.  It was
     introduced in Python 2.3 for backward compatibility with Python
     2.2, and was deprecated since Python 3.1.

   * Unknown escapes consisting of ‘'\'’ and an ASCII letter in
     replacement templates for *note re.sub(): 2a3. were deprecated in
     Python 3.5, and will now cause an error.

   * Removed support of the 'exclude' argument in *note
     tarfile.TarFile.add(): c14.  It was deprecated in Python 2.7 and
     3.2.  Use the 'filter' argument instead.

   * The ‘ntpath.splitunc()’ function was deprecated in Python 3.1, and
     has now been removed.  Use *note splitdrive(): c15. instead.

   * *note collections.namedtuple(): 1ca. no longer supports the
     'verbose' parameter or ‘_source’ attribute which showed the
     generated source code for the named tuple class.  This was part of
     an optimization designed to speed-up class creation.  (Contributed
     by Jelle Zijlstra with further improvements by INADA Naoki, Serhiy
     Storchaka, and Raymond Hettinger in bpo-28638(1).)

   * Functions *note bool(): 46b, *note float(): 2f7, *note list(): 614.
     and *note tuple(): 373. no longer take keyword arguments.  The
     first argument of *note int(): 257. can now be passed only as
     positional argument.

   * Removed previously deprecated in Python 2.4 classes ‘Plist’, ‘Dict’
     and ‘_InternalDict’ in the *note plistlib: ab. module.  Dict values
     in the result of functions ‘readPlist()’ and ‘readPlistFromBytes()’
     are now normal dicts.  You no longer can use attribute access to
     access items of these dictionaries.

   * The ‘asyncio.windows_utils.socketpair()’ function has been removed.
     Use the *note socket.socketpair(): c16. function instead, it is
     available on all platforms since Python 3.5.
     ‘asyncio.windows_utils.socketpair’ was just an alias to
     ‘socket.socketpair’ on Python 3.5 and newer.

   * *note asyncio: a. no longer exports the *note selectors: c2. and
     ‘_overlapped’ modules as ‘asyncio.selectors’ and
     ‘asyncio._overlapped’.  Replace ‘from asyncio import selectors’
     with ‘import selectors’.

   * Direct instantiation of *note ssl.SSLSocket: 8f3. and *note
     ssl.SSLObject: b9f. objects is now prohibited.  The constructors
     were never documented, tested, or designed as public constructors.
     Users were supposed to use ‘ssl.wrap_socket()’ or *note
     ssl.SSLContext: 294.  (Contributed by Christian Heimes in
     bpo-32951(2).)

   * The unused ‘distutils’ ‘install_misc’ command has been removed.
     (Contributed by Eric N. Vander Weele in bpo-29218(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28638

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32951

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29218


File: python.info,  Node: Module Removals,  Next: Windows-only Changes,  Prev: API and Feature Removals<2>,  Up: What’s New In Python 3 7

1.7.15 Module Removals
----------------------

The ‘fpectl’ module has been removed.  It was never enabled by default,
never worked correctly on x86-64, and it changed the Python ABI in ways
that caused unexpected breakage of C extensions.  (Contributed by
Nathaniel J. Smith in bpo-29137(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29137


File: python.info,  Node: Windows-only Changes,  Next: Porting to Python 3 7,  Prev: Module Removals,  Up: What’s New In Python 3 7

1.7.16 Windows-only Changes
---------------------------

The python launcher, (py.exe), can accept 32 & 64 bit specifiers
'without' having to specify a minor version as well.  So ‘py -3-32’ and
‘py -3-64’ become valid as well as ‘py -3.7-32’, also the -'m'-64 and
-'m.n'-64 forms are now accepted to force 64 bit python even if 32 bit
would have otherwise been used.  If the specified version is not
available py.exe will error exit.  (Contributed by Steve Barnes in
bpo-30291(1).)

The launcher can be run as ‘py -0’ to produce a list of the installed
pythons, 'with default marked with an asterisk'.  Running ‘py -0p’ will
include the paths.  If py is run with a version specifier that cannot be
matched it will also print the 'short form' list of available
specifiers.  (Contributed by Steve Barnes in bpo-30362(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30291

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30362


File: python.info,  Node: Porting to Python 3 7,  Next: Notable changes in Python 3 7 1,  Prev: Windows-only Changes,  Up: What’s New In Python 3 7

1.7.17 Porting to Python 3.7
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in Python Behavior::
* Changes in the Python API: Changes in the Python API<7>.
* Changes in the C API: Changes in the C API<5>.
* CPython bytecode changes: CPython bytecode changes<6>.
* Windows-only Changes: Windows-only Changes<2>.
* Other CPython implementation changes::


File: python.info,  Node: Changes in Python Behavior,  Next: Changes in the Python API<7>,  Up: Porting to Python 3 7

1.7.17.1 Changes in Python Behavior
...................................

   * *note async: 735. and *note await: 1b9. names are now reserved
     keywords.  Code using these names as identifiers will now raise a
     *note SyntaxError: 18d.  (Contributed by Jelle Zijlstra in
     bpo-30406(1).)

   * PEP 479(2) is enabled for all code in Python 3.7, meaning that
     *note StopIteration: c1b. exceptions raised directly or indirectly
     in coroutines and generators are transformed into *note
     RuntimeError: 195. exceptions.  (Contributed by Yury Selivanov in
     bpo-32670(3).)

   * *note object.__aiter__(): c1c. methods can no longer be declared as
     asynchronous.  (Contributed by Yury Selivanov in bpo-31709(4).)

   * Due to an oversight, earlier Python versions erroneously accepted
     the following syntax:

          f(1 for x in [1],)

          class C(1 for x in [1]):
              pass

     Python 3.7 now correctly raises a *note SyntaxError: 18d, as a
     generator expression always needs to be directly inside a set of
     parentheses and cannot have a comma on either side, and the
     duplication of the parentheses can be omitted only on calls.
     (Contributed by Serhiy Storchaka in bpo-32012(5) and bpo-32023(6).)

   * When using the *note -m: 5e4. switch, the initial working directory
     is now added to *note sys.path: 3b7, rather than an empty string
     (which dynamically denoted the current working directory at the
     time of each import).  Any programs that are checking for the empty
     string, or otherwise relying on the previous behaviour, will need
     to be updated accordingly (e.g.  by also checking for ‘os.getcwd()’
     or ‘os.path.dirname(__main__.__file__)’, depending on why the code
     was checking for the empty string in the first place).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30406

   (2) https://peps.python.org/pep-0479/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32670

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31709

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32012

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32023


File: python.info,  Node: Changes in the Python API<7>,  Next: Changes in the C API<5>,  Prev: Changes in Python Behavior,  Up: Porting to Python 3 7

1.7.17.2 Changes in the Python API
..................................

   * *note socketserver.ThreadingMixIn.server_close: b94. now waits
     until all non-daemon threads complete.  Set the new *note
     socketserver.ThreadingMixIn.block_on_close: b95. class attribute to
     ‘False’ to get the pre-3.7 behaviour.  (Contributed by Victor
     Stinner in bpo-31233(1) and bpo-33540(2).)

   * *note socketserver.ForkingMixIn.server_close: b94. now waits until
     all child processes complete.  Set the new *note
     socketserver.ForkingMixIn.block_on_close: b95. class attribute to
     ‘False’ to get the pre-3.7 behaviour.  (Contributed by Victor
     Stinner in bpo-31151(3) and bpo-33540(4).)

   * The *note locale.localeconv(): c1e. function now temporarily sets
     the ‘LC_CTYPE’ locale to the value of ‘LC_NUMERIC’ in some cases.
     (Contributed by Victor Stinner in bpo-31900(5).)

   * *note pkgutil.walk_packages(): c1f. now raises a *note ValueError:
     202. if 'path' is a string.  Previously an empty list was returned.
     (Contributed by Sanyam Khurana in bpo-24744(6).)

   * A format string argument for *note string.Formatter.format(): c20.
     is now *note positional-only: a94.  Passing it as a keyword
     argument was deprecated in Python 3.5.  (Contributed by Serhiy
     Storchaka in bpo-29193(7).)

   * Attributes *note key: c21, *note value: c22. and *note coded_value:
     c23. of class *note http.cookies.Morsel: c24. are now read-only.
     Assigning to them was deprecated in Python 3.5.  Use the *note
     set(): c25. method for setting them.  (Contributed by Serhiy
     Storchaka in bpo-29192(8).)

   * The 'mode' argument of *note os.makedirs(): 21e. no longer affects
     the file permission bits of newly created intermediate-level
     directories.  To set their file permission bits you can set the
     umask before invoking ‘makedirs()’.  (Contributed by Serhiy
     Storchaka in bpo-19930(9).)

   * The *note struct.Struct.format: c26. type is now *note str: 44f.
     instead of *note bytes: 1c2.  (Contributed by Victor Stinner in
     bpo-21071(10).)

   * ‘cgi.parse_multipart()’ now accepts the 'encoding' and 'errors'
     arguments and returns the same results as ‘FieldStorage’: for
     non-file fields, the value associated to a key is a list of
     strings, not bytes.  (Contributed by Pierre Quentel in
     bpo-29979(11).)

   * Due to internal changes in *note socket: cc, calling *note
     socket.fromshare(): c27. on a socket created by *note socket.share:
     c28. in older Python versions is not supported.

   * ‘repr’ for *note BaseException: 5be. has changed to not include the
     trailing comma.  Most exceptions are affected by this change.
     (Contributed by Serhiy Storchaka in bpo-30399(12).)

   * ‘repr’ for *note datetime.timedelta: 9da. has changed to include
     the keyword arguments in the output.  (Contributed by Utkarsh
     Upadhyay in bpo-30302(13).)

   * Because *note shutil.rmtree(): 301. is now implemented using the
     *note os.scandir(): a6d. function, the user specified handler
     'onerror' is now called with the first argument ‘os.scandir’
     instead of ‘os.listdir’ when listing the directory is failed.

   * Support for nested sets and set operations in regular expressions
     as in Unicode Technical Standard #18(14) might be added in the
     future.  This would change the syntax.  To facilitate this future
     change a *note FutureWarning: 418. will be raised in ambiguous
     cases for the time being.  That include sets starting with a
     literal ‘'['’ or containing literal character sequences ‘'--'’,
     ‘'&&'’, ‘'~~'’, and ‘'||'’.  To avoid a warning, escape them with a
     backslash.  (Contributed by Serhiy Storchaka in bpo-30349(15).)

   * The result of splitting a string on a *note regular expression: b9.
     that could match an empty string has been changed.  For example
     splitting on ‘r'\s*'’ will now split not only on whitespaces as it
     did previously, but also on empty strings before all non-whitespace
     characters and just before the end of the string.  The previous
     behavior can be restored by changing the pattern to ‘r'\s+'’.  A
     *note FutureWarning: 418. was emitted for such patterns since
     Python 3.5.

     For patterns that match both empty and non-empty strings, the
     result of searching for all matches may also be changed in other
     cases.  For example in the string ‘'a\n\n'’, the pattern
     ‘r'(?m)^\s*?$'’ will not only match empty strings at positions 2
     and 3, but also the string ‘'\n'’ at positions 2–3.  To match only
     blank lines, the pattern should be rewritten as
     ‘r'(?m)^[^\S\n]*$'’.

     *note re.sub(): 2a3. now replaces empty matches adjacent to a
     previous non-empty match.  For example ‘re.sub('x*', '-', 'abxd')’
     returns now ‘'-a-b--d-'’ instead of ‘'-a-b-d-'’ (the first minus
     between ‘b’ and ‘d’ replaces ‘x’, and the second minus replaces an
     empty string between ‘x’ and ‘d’).

     (Contributed by Serhiy Storchaka in bpo-25054(16) and
     bpo-32308(17).)

   * Change *note re.escape(): c29. to only escape regex special
     characters instead of escaping all characters other than ASCII
     letters, numbers, and ‘'_'’.  (Contributed by Serhiy Storchaka in
     bpo-29995(18).)

   * *note tracemalloc.Traceback: bb4. frames are now sorted from oldest
     to most recent to be more consistent with *note traceback: fe.
     (Contributed by Jesse Bakker in bpo-32121(19).)

   * On OSes that support *note socket.SOCK_NONBLOCK: c2a. or *note
     socket.SOCK_CLOEXEC: c2b. bit flags, the *note socket.type: c2c. no
     longer has them applied.  Therefore, checks like ‘if sock.type ==
     socket.SOCK_STREAM’ work as expected on all platforms.
     (Contributed by Yury Selivanov in bpo-32331(20).)

   * On Windows the default for the 'close_fds' argument of *note
     subprocess.Popen: 199. was changed from *note False: b4f. to *note
     True: c2d. when redirecting the standard handles.  If you
     previously depended on handles being inherited when using
     ‘subprocess.Popen’ with standard io redirection, you will have to
     pass ‘close_fds=False’ to preserve the previous behaviour, or use
     *note STARTUPINFO.lpAttributeList: c2e.

   * *note importlib.machinery.PathFinder.invalidate_caches(): c2f. –
     which implicitly affects *note importlib.invalidate_caches(): c30.
     – now deletes entries in *note sys.path_importer_cache: 5e7. which
     are set to ‘None’.  (Contributed by Brett Cannon in bpo-33169(21).)

   * In *note asyncio: a, *note loop.sock_recv(): c31, *note
     loop.sock_sendall(): c32, *note loop.sock_accept(): c33, *note
     loop.getaddrinfo(): c34, *note loop.getnameinfo(): c35. have been
     changed to be proper coroutine methods to match their
     documentation.  Previously, these methods returned *note
     asyncio.Future: bec. instances.  (Contributed by Yury Selivanov in
     bpo-32327(22).)

   * *note asyncio.Server.sockets: c36. now returns a copy of the
     internal list of server sockets, instead of returning it directly.
     (Contributed by Yury Selivanov in bpo-32662(23).)

   * *note Struct.format: c26. is now a *note str: 44f. instance instead
     of a *note bytes: 1c2. instance.  (Contributed by Victor Stinner in
     bpo-21071(24).)

   * *note argparse: 6. subparsers can now be made mandatory by passing
     ‘required=True’ to *note ArgumentParser.add_subparsers(): c37.
     (Contributed by Anthony Sottile in bpo-26510(25).)

   * *note ast.literal_eval(): c38. is now stricter.  Addition and
     subtraction of arbitrary numbers are no longer allowed.
     (Contributed by Serhiy Storchaka in bpo-31778(26).)

   * *note Calendar.itermonthdates: c39. will now consistently raise an
     exception when a date falls outside of the ‘0001-01-01’ through
     ‘9999-12-31’ range.  To support applications that cannot tolerate
     such exceptions, the new *note Calendar.itermonthdays3: c3a. and
     *note Calendar.itermonthdays4: c3b. can be used.  The new methods
     return tuples and are not restricted by the range supported by
     *note datetime.date: 1cd.  (Contributed by Alexander Belopolsky in
     bpo-28292(27).)

   * *note collections.ChainMap: c3c. now preserves the order of the
     underlying mappings.  (Contributed by Raymond Hettinger in
     bpo-32792(28).)

   * The ‘submit()’ method of *note
     concurrent.futures.ThreadPoolExecutor: 745. and *note
     concurrent.futures.ProcessPoolExecutor: 8f7. now raises a *note
     RuntimeError: 195. if called during interpreter shutdown.
     (Contributed by Mark Nemec in bpo-33097(29).)

   * The *note configparser.ConfigParser: 1c8. constructor now uses
     ‘read_dict()’ to process the default values, making its behavior
     consistent with the rest of the parser.  Non-string keys and values
     in the defaults dictionary are now being implicitly converted to
     strings.  (Contributed by James Tocknell in bpo-23835(30).)

   * Several undocumented internal imports were removed.  One example is
     that ‘os.errno’ is no longer available; use ‘import errno’ directly
     instead.  Note that such undocumented internal imports may be
     removed any time without notice, even in micro version releases.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31233

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33540

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31151

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33540

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31900

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24744

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29193

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29192

   (9) https://bugs.python.org/issue?@action=redirect&bpo=19930

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21071

   (11) https://bugs.python.org/issue?@action=redirect&bpo=29979

   (12) https://bugs.python.org/issue?@action=redirect&bpo=30399

   (13) https://bugs.python.org/issue?@action=redirect&bpo=30302

   (14) https://unicode.org/reports/tr18/

   (15) https://bugs.python.org/issue?@action=redirect&bpo=30349

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25054

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32308

   (18) https://bugs.python.org/issue?@action=redirect&bpo=29995

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32121

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32331

   (21) https://bugs.python.org/issue?@action=redirect&bpo=33169

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32327

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32662

   (24) https://bugs.python.org/issue?@action=redirect&bpo=21071

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26510

   (26) https://bugs.python.org/issue?@action=redirect&bpo=31778

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28292

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32792

   (29) https://bugs.python.org/issue?@action=redirect&bpo=33097

   (30) https://bugs.python.org/issue?@action=redirect&bpo=23835


File: python.info,  Node: Changes in the C API<5>,  Next: CPython bytecode changes<6>,  Prev: Changes in the Python API<7>,  Up: Porting to Python 3 7

1.7.17.3 Changes in the C API
.............................

The function *note PySlice_GetIndicesEx(): 3ff. is considered unsafe for
resizable sequences.  If the slice indices are not instances of *note
int: 257, but objects that implement the ‘__index__()’ method, the
sequence can be resized after passing its length to
‘PySlice_GetIndicesEx()’.  This can lead to returning indices out of the
length of the sequence.  For avoiding possible problems use new
functions *note PySlice_Unpack(): 400. and *note
PySlice_AdjustIndices(): 401.  (Contributed by Serhiy Storchaka in
bpo-27867(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27867


File: python.info,  Node: CPython bytecode changes<6>,  Next: Windows-only Changes<2>,  Prev: Changes in the C API<5>,  Up: Porting to Python 3 7

1.7.17.4 CPython bytecode changes
.................................

There are two new opcodes: *note LOAD_METHOD: c3f. and ‘CALL_METHOD’.
(Contributed by Yury Selivanov and INADA Naoki in bpo-26110(1).)

The ‘STORE_ANNOTATION’ opcode has been removed.  (Contributed by Mark
Shannon in bpo-32550(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26110

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32550


File: python.info,  Node: Windows-only Changes<2>,  Next: Other CPython implementation changes,  Prev: CPython bytecode changes<6>,  Up: Porting to Python 3 7

1.7.17.5 Windows-only Changes
.............................

The file used to override *note sys.path: 3b7. is now called
‘<python-executable>._pth’ instead of ‘'sys.path'’.  See *note Finding
modules: c41. for more information.  (Contributed by Steve Dower in
bpo-28137(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28137


File: python.info,  Node: Other CPython implementation changes,  Prev: Windows-only Changes<2>,  Up: Porting to Python 3 7

1.7.17.6 Other CPython implementation changes
.............................................

In preparation for potential future changes to the public CPython
runtime initialization API (see PEP 432(1) for an initial, but somewhat
outdated, draft), CPython’s internal startup and configuration
management logic has been significantly refactored.  While these updates
are intended to be entirely transparent to both embedding applications
and users of the regular CPython CLI, they’re being mentioned here as
the refactoring changes the internal order of various operations during
interpreter startup, and hence may uncover previously latent defects,
either in embedding applications, or in CPython itself.  (Initially
contributed by Nick Coghlan and Eric Snow as part of bpo-22257(2), and
further updated by Nick, Eric, and Victor Stinner in a number of other
issues).  Some known details affected:

   * ‘PySys_AddWarnOptionUnicode()’ is not currently usable by embedding
     applications due to the requirement to create a Unicode object
     prior to calling ‘Py_Initialize’.  Use ‘PySys_AddWarnOption()’
     instead.

   * warnings filters added by an embedding application with
     ‘PySys_AddWarnOption()’ should now more consistently take
     precedence over the default filters set by the interpreter

Due to changes in the way the default warnings filters are configured,
setting *note Py_BytesWarningFlag: 3d7. to a value greater than one is
no longer sufficient to both emit *note BytesWarning: c43. messages and
have them converted to exceptions.  Instead, the flag must be set (to
cause the warnings to be emitted in the first place), and an explicit
‘error::BytesWarning’ warnings filter added to convert them to
exceptions.

Due to a change in the way docstrings are handled by the compiler, the
implicit ‘return None’ in a function body consisting solely of a
docstring is now marked as occurring on the same line as the docstring,
not on the function’s header line.

The current exception state has been moved from the frame object to the
co-routine.  This simplified the interpreter and fixed a couple of
obscure bugs caused by having swap exception state when entering or
exiting a generator.  (Contributed by Mark Shannon in bpo-25612(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0432/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22257

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25612


File: python.info,  Node: Notable changes in Python 3 7 1,  Next: Notable changes in Python 3 7 2,  Prev: Porting to Python 3 7,  Up: What’s New In Python 3 7

1.7.18 Notable changes in Python 3.7.1
--------------------------------------

Starting in 3.7.1, *note Py_Initialize(): 8b4. now consistently reads
and respects all of the same environment settings as *note Py_Main():
c45. (in earlier Python versions, it respected an ill-defined subset of
those environment variables, while in Python 3.7.0 it didn’t read any of
them due to bpo-34247(1)).  If this behavior is unwanted, set *note
Py_IgnoreEnvironmentFlag: 3db. to 1 before calling ‘Py_Initialize()’.

In 3.7.1 the C API for Context Variables *note was updated: c46. to use
*note PyObject: 33a. pointers.  See also bpo-34762(2).

In 3.7.1 the *note tokenize: fb. module now implicitly emits a ‘NEWLINE’
token when provided with input that does not have a trailing new line.
This behavior now matches what the C tokenizer does internally.
(Contributed by Ammar Askar in bpo-33899(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34247

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34762

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33899


File: python.info,  Node: Notable changes in Python 3 7 2,  Next: Notable changes in Python 3 7 6,  Prev: Notable changes in Python 3 7 1,  Up: What’s New In Python 3 7

1.7.19 Notable changes in Python 3.7.2
--------------------------------------

In 3.7.2, *note venv: 111. on Windows no longer copies the original
binaries, but creates redirector scripts named ‘python.exe’ and
‘pythonw.exe’ instead.  This resolves a long standing issue where all
virtual environments would have to be upgraded or recreated with each
Python update.  However, note that this release will still require
recreation of virtual environments in order to get the new scripts.


File: python.info,  Node: Notable changes in Python 3 7 6,  Next: Notable changes in Python 3 7 10,  Prev: Notable changes in Python 3 7 2,  Up: What’s New In Python 3 7

1.7.20 Notable changes in Python 3.7.6
--------------------------------------

Due to significant security concerns, the 'reuse_address' parameter of
*note asyncio.loop.create_datagram_endpoint(): 736. is no longer
supported.  This is because of the behavior of the socket option
‘SO_REUSEADDR’ in UDP. For more details, see the documentation for
‘loop.create_datagram_endpoint()’.  (Contributed by Kyle Stanley,
Antoine Pitrou, and Yury Selivanov in bpo-37228(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37228


File: python.info,  Node: Notable changes in Python 3 7 10,  Next: Notable changes in Python 3 7 11,  Prev: Notable changes in Python 3 7 6,  Up: What’s New In Python 3 7

1.7.21 Notable changes in Python 3.7.10
---------------------------------------

Earlier Python versions allowed using both ‘;’ and ‘&’ as query
parameter separators in *note urllib.parse.parse_qs(): 27a. and *note
urllib.parse.parse_qsl(): 279.  Due to security concerns, and to conform
with newer W3C recommendations, this has been changed to allow only a
single separator key, with ‘&’ as the default.  This change also affects
‘cgi.parse()’ and ‘cgi.parse_multipart()’ as they use the affected
functions internally.  For more details, please see their respective
documentation.  (Contributed by Adam Goldschmidt, Senthil Kumaran and
Ken Jin in bpo-42967(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967


File: python.info,  Node: Notable changes in Python 3 7 11,  Next: Notable security feature in 3 7 14,  Prev: Notable changes in Python 3 7 10,  Up: What’s New In Python 3 7

1.7.22 Notable changes in Python 3.7.11
---------------------------------------

A security fix alters the *note ftplib.FTP: 903. behavior to not trust
the IPv4 address sent from the remote server when setting up a passive
data channel.  We reuse the ftp server IP address instead.  For unusual
code requiring the old behavior, set a ‘trust_server_pasv_ipv4_address’
attribute on your FTP instance to ‘True’.  (See gh-87451(1))

The presence of newline or tab characters in parts of a URL allows for
some forms of attacks.  Following the WHATWG specification that updates
RFC 3986, ASCII newline ‘\n’, ‘\r’ and tab ‘\t’ characters are stripped
from the URL by the parser *note urllib.parse(): 10a. preventing such
attacks.  The removal characters are controlled by a new module level
variable ‘urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE’.  (See gh-88048(2))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87451

   (2) https://github.com/python/cpython/issues/88048


File: python.info,  Node: Notable security feature in 3 7 14,  Prev: Notable changes in Python 3 7 11,  Up: What’s New In Python 3 7

1.7.23 Notable security feature in 3.7.14
-----------------------------------------

Converting between *note int: 257. and *note str: 44f. in bases other
than 2 (binary), 4, 8 (octal), 16 (hexadecimal), or 32 such as base 10
(decimal) now raises a *note ValueError: 202. if the number of digits in
string form is above a limit to avoid potential denial of service
attacks due to the algorithmic complexity.  This is a mitigation for CVE
2020-10735(1).  This limit can be configured or disabled by environment
variable, command line flag, or *note sys: d9. APIs.  See the *note
integer string conversion length limitation: 5f8. documentation.  The
default limit is 4300 digits in string form.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: What’s New In Python 3 6,  Next: What’s New In Python 3 5,  Prev: What’s New In Python 3 7,  Up: What’s New in Python

1.8 What’s New In Python 3.6
============================


Editors: Elvis Pranskevichus <<elvis@magic.io>>, Yury Selivanov
<<yury@magic.io>>

This article explains the new features in Python 3.6, compared to 3.5.
Python 3.6 was released on December 23, 2016.   See the changelog(1) for
a full list of changes.

See also
........

PEP 494(2) - Python 3.6 Release Schedule

* Menu:

* Summary – Release highlights: Summary – Release highlights<6>.
* New Features: New Features<13>.
* Other Language Changes: Other Language Changes<8>.
* New Modules: New Modules<8>.
* Improved Modules: Improved Modules<8>.
* Optimizations: Optimizations<8>.
* Build and C API Changes: Build and C API Changes<2>.
* Other Improvements::
* Deprecated: Deprecated<9>.
* Removed: Removed<9>.
* Porting to Python 3.6: Porting to Python 3 6.
* Notable changes in Python 3.6.2: Notable changes in Python 3 6 2.
* Notable changes in Python 3.6.4: Notable changes in Python 3 6 4.
* Notable changes in Python 3.6.5: Notable changes in Python 3 6 5.
* Notable changes in Python 3.6.7: Notable changes in Python 3 6 7.
* Notable changes in Python 3.6.10: Notable changes in Python 3 6 10.
* Notable changes in Python 3.6.13: Notable changes in Python 3 6 13.
* Notable changes in Python 3.6.14: Notable changes in Python 3 6 14.

   ---------- Footnotes ----------

   (1) https://docs.python.org/3.6/whatsnew/changelog.html

   (2) https://peps.python.org/pep-0494/


File: python.info,  Node: Summary – Release highlights<6>,  Next: New Features<13>,  Up: What’s New In Python 3 6

1.8.1 Summary – Release highlights
----------------------------------

New syntax features:

   * *note PEP 498: c50, formatted string literals.

   * *note PEP 515: c51, underscores in numeric literals.

   * *note PEP 526: c52, syntax for variable annotations.

   * *note PEP 525: c53, asynchronous generators.

   * *note PEP 530: c54.: asynchronous comprehensions.

New library modules:

   * *note secrets: c0.: *note PEP 506 – Adding A Secrets Module To The
     Standard Library: c55.

CPython implementation improvements:

   * The *note dict: adc. type has been reimplemented to use a *note
     more compact representation: c56. based on a proposal by Raymond
     Hettinger(1) and similar to the PyPy dict implementation(2).  This
     resulted in dictionaries using 20% to 25% less memory when compared
     to Python 3.5.

   * Customization of class creation has been simplified with the *note
     new protocol: c57.

   * The class attribute definition order is *note now preserved: c58.

   * The order of elements in ‘**kwargs’ now *note corresponds to the
     order: c59. in which keyword arguments were passed to the function.

   * DTrace and SystemTap *note probing support: c5a. has been added.

   * The new *note PYTHONMALLOC: c5b. environment variable can now be
     used to debug the interpreter memory allocation and access errors.

Significant improvements in the standard library:

   * The *note asyncio: a. module has received new features, significant
     usability and performance improvements, and a fair amount of bug
     fixes.  Starting with Python 3.6 the ‘asyncio’ module is no longer
     provisional and its API is considered stable.

   * A new *note file system path protocol: c5c. has been implemented to
     support *note path-like objects: 2a0.  All standard library
     functions operating on paths have been updated to work with the new
     protocol.

   * The *note datetime: 30. module has gained support for *note Local
     Time Disambiguation: c5d.

   * The *note typing: 104. module received a number of *note
     improvements: c5e.

   * The *note tracemalloc: ff. module has been significantly reworked
     and is now used to provide better output for *note ResourceWarning:
     244. as well as provide better diagnostics for memory allocation
     errors.  See the *note PYTHONMALLOC section: c5b. for more
     information.

Security improvements:

   * The new *note secrets: c0. module has been added to simplify the
     generation of cryptographically strong pseudo-random numbers
     suitable for managing secrets such as account authentication,
     tokens, and similar.

   * On Linux, *note os.urandom(): 526. now blocks until the system
     urandom entropy pool is initialized to increase the security.  See
     the PEP 524(3) for the rationale.

   * The *note hashlib: 68. and *note ssl: d0. modules now support
     OpenSSL 1.1.0.

   * The default settings and feature set of the *note ssl: d0. module
     have been improved.

   * The *note hashlib: 68. module received support for the BLAKE2,
     SHA-3 and SHAKE hash algorithms and the *note scrypt(): c5f. key
     derivation function.

Windows improvements:

   * *note PEP 528: c60. and *note PEP 529: c61, Windows filesystem and
     console encoding changed to UTF-8.

   * The ‘py.exe’ launcher, when used interactively, no longer prefers
     Python 2 over Python 3 when the user doesn’t specify a version (via
     command line arguments or a config file).  Handling of shebang
     lines remains unchanged - “python” refers to Python 2 in that case.

   * ‘python.exe’ and ‘pythonw.exe’ have been marked as long-path aware,
     which means that the 260 character path limit may no longer apply.
     See *note removing the MAX_PATH limitation: c62. for details.

   * A ‘._pth’ file can be added to force isolated mode and fully
     specify all search paths to avoid registry and environment lookup.
     See *note the documentation: c41. for more information.

   * A ‘python36.zip’ file now works as a landmark to infer *note
     PYTHONHOME: 3bf.  See *note the documentation: c41. for more
     information.

   ---------- Footnotes ----------

   (1) 
https://mail.python.org/pipermail/python-dev/2012-December/123028.html

   (2) 
https://morepypy.blogspot.com/2015/01/faster-more-memory-efficient-and-more.html

   (3) https://peps.python.org/pep-0524/


File: python.info,  Node: New Features<13>,  Next: Other Language Changes<8>,  Prev: Summary – Release highlights<6>,  Up: What’s New In Python 3 6

1.8.2 New Features
------------------

* Menu:

* PEP 498; Formatted string literals: PEP 498 Formatted string literals.
* PEP 526; Syntax for variable annotations: PEP 526 Syntax for variable annotations.
* PEP 515; Underscores in Numeric Literals: PEP 515 Underscores in Numeric Literals.
* PEP 525; Asynchronous Generators: PEP 525 Asynchronous Generators.
* PEP 530; Asynchronous Comprehensions: PEP 530 Asynchronous Comprehensions.
* PEP 487; Simpler customization of class creation: PEP 487 Simpler customization of class creation.
* PEP 487; Descriptor Protocol Enhancements: PEP 487 Descriptor Protocol Enhancements.
* PEP 519; Adding a file system path protocol: PEP 519 Adding a file system path protocol.
* PEP 495; Local Time Disambiguation: PEP 495 Local Time Disambiguation.
* PEP 529; Change Windows filesystem encoding to UTF-8: PEP 529 Change Windows filesystem encoding to UTF-8.
* PEP 528; Change Windows console encoding to UTF-8: PEP 528 Change Windows console encoding to UTF-8.
* PEP 520; Preserving Class Attribute Definition Order: PEP 520 Preserving Class Attribute Definition Order.
* PEP 468; Preserving Keyword Argument Order: PEP 468 Preserving Keyword Argument Order.
* New dict implementation::
* PEP 523; Adding a frame evaluation API to CPython: PEP 523 Adding a frame evaluation API to CPython.
* PYTHONMALLOC environment variable::
* DTrace and SystemTap probing support::


File: python.info,  Node: PEP 498 Formatted string literals,  Next: PEP 526 Syntax for variable annotations,  Up: New Features<13>

1.8.2.1 PEP 498: Formatted string literals
..........................................

PEP 498(1) introduces a new kind of string literals: 'f-strings', or
*note formatted string literals: 9b4.

Formatted string literals are prefixed with ‘'f'’ and are similar to the
format strings accepted by *note str.format(): 624.  They contain
replacement fields surrounded by curly braces.  The replacement fields
are expressions, which are evaluated at run time, and then formatted
using the *note format(): 622. protocol:

     >>> name = "Fred"
     >>> f"He said his name is {name}."
     'He said his name is Fred.'
     >>> width = 10
     >>> precision = 4
     >>> value = decimal.Decimal("12.34567")
     >>> f"result: {value:{width}.{precision}}"  # nested fields
     'result:      12.35'

See also
........

PEP 498(2) – Literal String Interpolation.

     PEP written and implemented by Eric V. Smith.

*note Feature documentation: 9b4.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0498/

   (2) https://peps.python.org/pep-0498/


File: python.info,  Node: PEP 526 Syntax for variable annotations,  Next: PEP 515 Underscores in Numeric Literals,  Prev: PEP 498 Formatted string literals,  Up: New Features<13>

1.8.2.2 PEP 526: Syntax for variable annotations
................................................

PEP 484(1) introduced the standard for type annotations of function
parameters, a.k.a.  type hints.  This PEP adds syntax to Python for
annotating the types of variables including class variables and instance
variables:

     primes: List[int] = []

     captain: str  # Note: no initial value!

     class Starship:
         stats: Dict[str, int] = {}

Just as for function annotations, the Python interpreter does not attach
any particular meaning to variable annotations and only stores them in
the ‘__annotations__’ attribute of a class or module.

In contrast to variable declarations in statically typed languages, the
goal of annotation syntax is to provide an easy way to specify
structured type metadata for third party tools and libraries via the
abstract syntax tree and the ‘__annotations__’ attribute.

See also
........

PEP 526(2) – Syntax for variable annotations.

     PEP written by Ryan Gonzalez, Philip House, Ivan Levkivskyi, Lisa
     Roach, and Guido van Rossum.  Implemented by Ivan Levkivskyi.

Tools that use or will use the new syntax: mypy(3), pytype(4), PyCharm,
etc.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0526/

   (3) https://www.mypy-lang.org/

   (4) https://github.com/google/pytype


File: python.info,  Node: PEP 515 Underscores in Numeric Literals,  Next: PEP 525 Asynchronous Generators,  Prev: PEP 526 Syntax for variable annotations,  Up: New Features<13>

1.8.2.3 PEP 515: Underscores in Numeric Literals
................................................

PEP 515(1) adds the ability to use underscores in numeric literals for
improved readability.  For example:

     >>> 1_000_000_000_000_000
     1000000000000000
     >>> 0x_FF_FF_FF_FF
     4294967295

Single underscores are allowed between digits and after any base
specifier.  Leading, trailing, or multiple underscores in a row are not
allowed.

The *note string formatting: 1e8. language also now has support for the
‘'_'’ option to signal the use of an underscore for a thousands
separator for floating-point presentation types and for integer
presentation type ‘'d'’.  For integer presentation types ‘'b'’, ‘'o'’,
‘'x'’, and ‘'X'’, underscores will be inserted every 4 digits:

     >>> '{:_}'.format(1000000)
     '1_000_000'
     >>> '{:_x}'.format(0xFFFFFFFF)
     'ffff_ffff'

See also
........

PEP 515(2) – Underscores in Numeric Literals

     PEP written by Georg Brandl and Serhiy Storchaka.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0515/

   (2) https://peps.python.org/pep-0515/


File: python.info,  Node: PEP 525 Asynchronous Generators,  Next: PEP 530 Asynchronous Comprehensions,  Prev: PEP 515 Underscores in Numeric Literals,  Up: New Features<13>

1.8.2.4 PEP 525: Asynchronous Generators
........................................

PEP 492(1) introduced support for native coroutines and ‘async’ /
‘await’ syntax to Python 3.5.  A notable limitation of the Python 3.5
implementation is that it was not possible to use ‘await’ and ‘yield’ in
the same function body.  In Python 3.6 this restriction has been lifted,
making it possible to define 'asynchronous generators':

     async def ticker(delay, to):
         """Yield numbers from 0 to *to* every *delay* seconds."""
         for i in range(to):
             yield i
             await asyncio.sleep(delay)

The new syntax allows for faster and more concise code.

See also
........

PEP 525(2) – Asynchronous Generators

     PEP written and implemented by Yury Selivanov.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/

   (2) https://peps.python.org/pep-0525/


File: python.info,  Node: PEP 530 Asynchronous Comprehensions,  Next: PEP 487 Simpler customization of class creation,  Prev: PEP 525 Asynchronous Generators,  Up: New Features<13>

1.8.2.5 PEP 530: Asynchronous Comprehensions
............................................

PEP 530(1) adds support for using ‘async for’ in list, set, dict
comprehensions and generator expressions:

     result = [i async for i in aiter() if i % 2]

Additionally, ‘await’ expressions are supported in all kinds of
comprehensions:

     result = [await fun() for fun in funcs if await condition()]

See also
........

PEP 530(2) – Asynchronous Comprehensions

     PEP written and implemented by Yury Selivanov.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0530/

   (2) https://peps.python.org/pep-0530/


File: python.info,  Node: PEP 487 Simpler customization of class creation,  Next: PEP 487 Descriptor Protocol Enhancements,  Prev: PEP 530 Asynchronous Comprehensions,  Up: New Features<13>

1.8.2.6 PEP 487: Simpler customization of class creation
........................................................

It is now possible to customize subclass creation without using a
metaclass.  The new ‘__init_subclass__’ classmethod will be called on
the base class whenever a new subclass is created:

     class PluginBase:
         subclasses = []

         def __init_subclass__(cls, **kwargs):
             super().__init_subclass__(**kwargs)
             cls.subclasses.append(cls)

     class Plugin1(PluginBase):
         pass

     class Plugin2(PluginBase):
         pass

In order to allow zero-argument *note super(): 4de. calls to work
correctly from *note __init_subclass__(): 634. implementations, custom
metaclasses must ensure that the new ‘__classcell__’ namespace entry is
propagated to ‘type.__new__’ (as described in *note Creating the class
object: c6b.).

See also
........

PEP 487(1) – Simpler customization of class creation

     PEP written and implemented by Martin Teichmann.

*note Feature documentation: c6c.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0487/


File: python.info,  Node: PEP 487 Descriptor Protocol Enhancements,  Next: PEP 519 Adding a file system path protocol,  Prev: PEP 487 Simpler customization of class creation,  Up: New Features<13>

1.8.2.7 PEP 487: Descriptor Protocol Enhancements
.................................................

PEP 487(1) extends the descriptor protocol to include the new optional
*note __set_name__(): c6f. method.  Whenever a new class is defined, the
new method will be called on all descriptors included in the definition,
providing them with a reference to the class being defined and the name
given to the descriptor within the class namespace.  In other words,
instances of descriptors can now know the attribute name of the
descriptor in the owner class:

     class IntField:
         def __get__(self, instance, owner):
             return instance.__dict__[self.name]

         def __set__(self, instance, value):
             if not isinstance(value, int):
                 raise ValueError(f'expecting integer in {self.name}')
             instance.__dict__[self.name] = value

         # this is the new initializer:
         def __set_name__(self, owner, name):
             self.name = name

     class Model:
         int_field = IntField()

See also
........

PEP 487(2) – Simpler customization of class creation

     PEP written and implemented by Martin Teichmann.

*note Feature documentation: c70.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0487/

   (2) https://peps.python.org/pep-0487/


File: python.info,  Node: PEP 519 Adding a file system path protocol,  Next: PEP 495 Local Time Disambiguation,  Prev: PEP 487 Descriptor Protocol Enhancements,  Up: New Features<13>

1.8.2.8 PEP 519: Adding a file system path protocol
...................................................

File system paths have historically been represented as *note str: 44f.
or *note bytes: 1c2. objects.  This has led to people who write code
which operate on file system paths to assume that such objects are only
one of those two types (an *note int: 257. representing a file
descriptor does not count as that is not a file path).  Unfortunately
that assumption prevents alternative object representations of file
system paths like *note pathlib: a4. from working with pre-existing
code, including Python’s standard library.

To fix this situation, a new interface represented by *note os.PathLike:
c72. has been defined.  By implementing the *note __fspath__(): c73.
method, an object signals that it represents a path.  An object can then
provide a low-level representation of a file system path as a *note str:
44f. or *note bytes: 1c2. object.  This means an object is considered
*note path-like: 2a0. if it implements ‘os.PathLike’ or is a ‘str’ or
‘bytes’ object which represents a file system path.  Code can use *note
os.fspath(): c74, *note os.fsdecode(): c75, or *note os.fsencode(): c76.
to explicitly get a ‘str’ and/or ‘bytes’ representation of a path-like
object.

The built-in *note open(): 51f. function has been updated to accept
*note os.PathLike: c72. objects, as have all relevant functions in the
*note os: a1. and *note os.path: a2. modules, and most other functions
and classes in the standard library.  The *note os.DirEntry: 49e. class
and relevant classes in *note pathlib: a4. have also been updated to
implement ‘os.PathLike’.

The hope is that updating the fundamental functions for operating on
file system paths will lead to third-party code to implicitly support
all *note path-like objects: 2a0. without any code changes, or at least
very minimal ones (e.g.  calling *note os.fspath(): c74. at the
beginning of code before operating on a path-like object).

Here are some examples of how the new interface allows for *note
pathlib.Path: 229. to be used more easily and transparently with
pre-existing code:

     >>> import pathlib
     >>> with open(pathlib.Path("README")) as f:
     ...     contents = f.read()
     ...
     >>> import os.path
     >>> os.path.splitext(pathlib.Path("some_file.txt"))
     ('some_file', '.txt')
     >>> os.path.join("/a/b", pathlib.Path("c"))
     '/a/b/c'
     >>> import os
     >>> os.fspath(pathlib.Path("some_file.txt"))
     'some_file.txt'

(Implemented by Brett Cannon, Ethan Furman, Dusty Phillips, and Jelle
Zijlstra.)

See also
........

PEP 519(1) – Adding a file system path protocol

     PEP written by Brett Cannon and Koos Zevenhoven.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0519/


File: python.info,  Node: PEP 495 Local Time Disambiguation,  Next: PEP 529 Change Windows filesystem encoding to UTF-8,  Prev: PEP 519 Adding a file system path protocol,  Up: New Features<13>

1.8.2.9 PEP 495: Local Time Disambiguation
..........................................

In most world locations, there have been and will be times when local
clocks are moved back.  In those times, intervals are introduced in
which local clocks show the same time twice in the same day.  In these
situations, the information displayed on a local clock (or stored in a
Python datetime instance) is insufficient to identify a particular
moment in time.

PEP 495(1) adds the new 'fold' attribute to instances of *note
datetime.datetime: 1cc. and *note datetime.time: 1ce. classes to
differentiate between two moments in time for which local times are the
same:

     >>> u0 = datetime(2016, 11, 6, 4, tzinfo=timezone.utc)
     >>> for i in range(4):
     ...     u = u0 + i*HOUR
     ...     t = u.astimezone(Eastern)
     ...     print(u.time(), 'UTC =', t.time(), t.tzname(), t.fold)
     ...
     04:00:00 UTC = 00:00:00 EDT 0
     05:00:00 UTC = 01:00:00 EDT 0
     06:00:00 UTC = 01:00:00 EST 1
     07:00:00 UTC = 02:00:00 EST 0

The values of the *note fold: c78. attribute have the value ‘0’ for all
instances except those that represent the second (chronologically)
moment in time in an ambiguous case.

See also
........

PEP 495(2) – Local Time Disambiguation

     PEP written by Alexander Belopolsky and Tim Peters, implementation
     by Alexander Belopolsky.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0495/

   (2) https://peps.python.org/pep-0495/


File: python.info,  Node: PEP 529 Change Windows filesystem encoding to UTF-8,  Next: PEP 528 Change Windows console encoding to UTF-8,  Prev: PEP 495 Local Time Disambiguation,  Up: New Features<13>

1.8.2.10 PEP 529: Change Windows filesystem encoding to UTF-8
.............................................................

Representing filesystem paths is best performed with str (Unicode)
rather than bytes.  However, there are some situations where using bytes
is sufficient and correct.

Prior to Python 3.6, data loss could result when using bytes paths on
Windows.  With this change, using bytes to represent paths is now
supported on Windows, provided those bytes are encoded with the encoding
returned by *note sys.getfilesystemencoding(): c7a, which now defaults
to ‘'utf-8'’.

Applications that do not use str to represent paths should use *note
os.fsencode(): c76. and *note os.fsdecode(): c75. to ensure their bytes
are correctly encoded.  To revert to the previous behaviour, set *note
PYTHONLEGACYWINDOWSFSENCODING: 2af. or call *note
sys._enablelegacywindowsfsencoding(): 2ae.

See PEP 529(1) for more information and discussion of code modifications
that may be required.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0529/


File: python.info,  Node: PEP 528 Change Windows console encoding to UTF-8,  Next: PEP 520 Preserving Class Attribute Definition Order,  Prev: PEP 529 Change Windows filesystem encoding to UTF-8,  Up: New Features<13>

1.8.2.11 PEP 528: Change Windows console encoding to UTF-8
..........................................................

The default console on Windows will now accept all Unicode characters
and provide correctly read str objects to Python code.  ‘sys.stdin’,
‘sys.stdout’ and ‘sys.stderr’ now default to utf-8 encoding.

This change only applies when using an interactive console, and not when
redirecting files or pipes.  To revert to the previous behaviour for
interactive console use, set *note PYTHONLEGACYWINDOWSSTDIO: c7c.

See also
........

PEP 528(1) – Change Windows console encoding to UTF-8

     PEP written and implemented by Steve Dower.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0528/


File: python.info,  Node: PEP 520 Preserving Class Attribute Definition Order,  Next: PEP 468 Preserving Keyword Argument Order,  Prev: PEP 528 Change Windows console encoding to UTF-8,  Up: New Features<13>

1.8.2.12 PEP 520: Preserving Class Attribute Definition Order
.............................................................

Attributes in a class definition body have a natural ordering: the same
order in which the names appear in the source.  This order is now
preserved in the new class’s *note __dict__: c7e. attribute.

Also, the effective default class 'execution' namespace (returned from
*note type.__prepare__(): c7f.) is now an insertion-order-preserving
mapping.

See also
........

PEP 520(1) – Preserving Class Attribute Definition Order

     PEP written and implemented by Eric Snow.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0520/


File: python.info,  Node: PEP 468 Preserving Keyword Argument Order,  Next: New dict implementation,  Prev: PEP 520 Preserving Class Attribute Definition Order,  Up: New Features<13>

1.8.2.13 PEP 468: Preserving Keyword Argument Order
...................................................

‘**kwargs’ in a function signature is now guaranteed to be an
insertion-order-preserving mapping.

See also
........

PEP 468(1) – Preserving Keyword Argument Order

     PEP written and implemented by Eric Snow.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0468/


File: python.info,  Node: New dict implementation,  Next: PEP 523 Adding a frame evaluation API to CPython,  Prev: PEP 468 Preserving Keyword Argument Order,  Up: New Features<13>

1.8.2.14 New dict implementation
................................

The *note dict: adc. type now uses a “compact” representation based on a
proposal by Raymond Hettinger(1) which was first implemented by PyPy(2).
The memory usage of the new *note dict(): 256. is between 20% and 25%
smaller compared to Python 3.5.

The order-preserving aspect of this new implementation is considered an
implementation detail and should not be relied upon (this may change in
the future, but it is desired to have this new dict implementation in
the language for a few releases before changing the language spec to
mandate order-preserving semantics for all current and future Python
implementations; this also helps preserve backwards-compatibility with
older versions of the language where random iteration order is still in
effect, e.g.  Python 3.5).

(Contributed by INADA Naoki in bpo-27350(3).  Idea originally suggested
by Raymond Hettinger(4).)

   ---------- Footnotes ----------

   (1) 
https://mail.python.org/pipermail/python-dev/2012-December/123028.html

   (2) 
https://morepypy.blogspot.com/2015/01/faster-more-memory-efficient-and-more.html

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27350

   (4) 
https://mail.python.org/pipermail/python-dev/2012-December/123028.html


File: python.info,  Node: PEP 523 Adding a frame evaluation API to CPython,  Next: PYTHONMALLOC environment variable,  Prev: New dict implementation,  Up: New Features<13>

1.8.2.15 PEP 523: Adding a frame evaluation API to CPython
..........................................................

While Python provides extensive support to customize how code executes,
one place it has not done so is in the evaluation of frame objects.  If
you wanted some way to intercept frame evaluation in Python there really
wasn’t any way without directly manipulating function pointers for
defined functions.

PEP 523(1) changes this by providing an API to make frame evaluation
pluggable at the C level.  This will allow for tools such as debuggers
and JITs to intercept frame evaluation before the execution of Python
code begins.  This enables the use of alternative evaluation
implementations for Python code, tracking frame evaluation, etc.

This API is not part of the limited C API and is marked as private to
signal that usage of this API is expected to be limited and only
applicable to very select, low-level use-cases.  Semantics of the API
will change with Python as necessary.

See also
........

PEP 523(2) – Adding a frame evaluation API to CPython

     PEP written by Brett Cannon and Dino Viehland.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0523/

   (2) https://peps.python.org/pep-0523/


File: python.info,  Node: PYTHONMALLOC environment variable,  Next: DTrace and SystemTap probing support,  Prev: PEP 523 Adding a frame evaluation API to CPython,  Up: New Features<13>

1.8.2.16 PYTHONMALLOC environment variable
..........................................

The new *note PYTHONMALLOC: c85. environment variable allows setting the
Python memory allocators and installing debug hooks.

It is now possible to install debug hooks on Python memory allocators on
Python compiled in release mode using ‘PYTHONMALLOC=debug’.  Effects of
debug hooks:

   * Newly allocated memory is filled with the byte ‘0xCB’

   * Freed memory is filled with the byte ‘0xDB’

   * Detect violations of the Python memory allocator API. For example,
     *note PyObject_Free(): c86. called on a memory block allocated by
     *note PyMem_Malloc(): c87.

   * Detect writes before the start of a buffer (buffer underflows)

   * Detect writes after the end of a buffer (buffer overflows)

   * Check that the *note GIL: 148. is held when allocator functions of
     *note PYMEM_DOMAIN_OBJ: c88. (ex: *note PyObject_Malloc(): c89.)
     and *note PYMEM_DOMAIN_MEM: c8a. (ex: *note PyMem_Malloc(): c87.)
     domains are called.

Checking if the GIL is held is also a new feature of Python 3.6.

See the *note PyMem_SetupDebugHooks(): c8b. function for debug hooks on
Python memory allocators.

It is now also possible to force the usage of the ‘malloc()’ allocator
of the C library for all Python memory allocations using
‘PYTHONMALLOC=malloc’.  This is helpful when using external memory
debuggers like Valgrind on a Python compiled in release mode.

On error, the debug hooks on Python memory allocators now use the *note
tracemalloc: ff. module to get the traceback where a memory block was
allocated.

Example of fatal error on buffer overflow using ‘python3.6 -X
tracemalloc=5’ (store 5 frames in traces):

     Debug memory block at address p=0x7fbcd41666f8: API 'o'
         4 bytes originally requested
         The 7 pad bytes at p-7 are FORBIDDENBYTE, as expected.
         The 8 pad bytes at tail=0x7fbcd41666fc are not all FORBIDDENBYTE (0xfb):
             at tail+0: 0x02 *** OUCH
             at tail+1: 0xfb
             at tail+2: 0xfb
             at tail+3: 0xfb
             at tail+4: 0xfb
             at tail+5: 0xfb
             at tail+6: 0xfb
             at tail+7: 0xfb
         The block was made by call #1233329 to debug malloc/realloc.
         Data at p: 1a 2b 30 00

     Memory block allocated at (most recent call first):
       File "test/test_bytes.py", line 323
       File "unittest/case.py", line 600
       File "unittest/case.py", line 648
       File "unittest/suite.py", line 122
       File "unittest/suite.py", line 84

     Fatal Python error: bad trailing pad byte

     Current thread 0x00007fbcdbd32700 (most recent call first):
       File "test/test_bytes.py", line 323 in test_hex
       File "unittest/case.py", line 600 in run
       File "unittest/case.py", line 648 in __call__
       File "unittest/suite.py", line 122 in run
       File "unittest/suite.py", line 84 in __call__
       File "unittest/suite.py", line 122 in run
       File "unittest/suite.py", line 84 in __call__
       ...

(Contributed by Victor Stinner in bpo-26516(1) and bpo-26564(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26516

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26564


File: python.info,  Node: DTrace and SystemTap probing support,  Prev: PYTHONMALLOC environment variable,  Up: New Features<13>

1.8.2.17 DTrace and SystemTap probing support
.............................................

Python can now be built ‘--with-dtrace’ which enables static markers for
the following events in the interpreter:

   * function call/return

   * garbage collection started/finished

   * line of code executed.

This can be used to instrument running interpreters in production,
without the need to recompile specific *note debug builds: 1f9. or
providing application-specific profiling/debugging code.

More details in *note Instrumenting CPython with DTrace and SystemTap:
c8d.

The current implementation is tested on Linux and macOS. Additional
markers may be added in the future.

(Contributed by Łukasz Langa in bpo-21590(1), based on patches by Jesús
Cea Avión, David Malcolm, and Nikhil Benesch.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21590


File: python.info,  Node: Other Language Changes<8>,  Next: New Modules<8>,  Prev: New Features<13>,  Up: What’s New In Python 3 6

1.8.3 Other Language Changes
----------------------------

Some smaller changes made to the core Python language are:

   * A ‘global’ or ‘nonlocal’ statement must now textually appear before
     the first use of the affected name in the same scope.  Previously
     this was a *note SyntaxWarning: 469.

   * It is now possible to set a *note special method: c8f. to ‘None’ to
     indicate that the corresponding operation is not available.  For
     example, if a class sets *note __iter__(): c90. to ‘None’, the
     class is not iterable.  (Contributed by Andrew Barnert and Ivan
     Levkivskyi in bpo-25958(1).)

   * Long sequences of repeated traceback lines are now abbreviated as
     ‘"[Previous line repeated {count} more times]"’ (see *note
     traceback: c91. for an example).  (Contributed by Emanuel Barry in
     bpo-26823(2).)

   * Import now raises the new exception *note ModuleNotFoundError: b61.
     (subclass of *note ImportError: 41c.) when it cannot find a module.
     Code that currently checks for ImportError (in try-except) will
     still work.  (Contributed by Eric Snow in bpo-15767(3).)

   * Class methods relying on zero-argument ‘super()’ will now work
     correctly when called from metaclass methods during class creation.
     (Contributed by Martin Teichmann in bpo-23722(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25958

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26823

   (3) https://bugs.python.org/issue?@action=redirect&bpo=15767

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23722


File: python.info,  Node: New Modules<8>,  Next: Improved Modules<8>,  Prev: Other Language Changes<8>,  Up: What’s New In Python 3 6

1.8.4 New Modules
-----------------

* Menu:

* secrets::


File: python.info,  Node: secrets,  Up: New Modules<8>

1.8.4.1 secrets
...............

The main purpose of the new *note secrets: c0. module is to provide an
obvious way to reliably generate cryptographically strong pseudo-random
values suitable for managing secrets, such as account authentication,
tokens, and similar.

     Warning: Note that the pseudo-random generators in the *note
     random: b8. module should 'NOT' be used for security purposes.  Use
     *note secrets: c0. on Python 3.6+ and *note os.urandom(): 526. on
     Python 3.5 and earlier.

See also
........

PEP 506(1) – Adding A Secrets Module To The Standard Library

     PEP written and implemented by Steven D’Aprano.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0506/


File: python.info,  Node: Improved Modules<8>,  Next: Optimizations<8>,  Prev: New Modules<8>,  Up: What’s New In Python 3 6

1.8.5 Improved Modules
----------------------

* Menu:

* array: array<4>.
* ast: ast<4>.
* asyncio: asyncio<9>.
* binascii: binascii<2>.
* cmath::
* collections: collections<4>.
* concurrent.futures: concurrent futures<4>.
* contextlib: contextlib<4>.
* datetime: datetime<5>.
* decimal: decimal<2>.
* distutils: distutils<5>.
* email: email<2>.
* encodings: encodings<2>.
* enum: enum<7>.
* faulthandler: faulthandler<2>.
* fileinput: fileinput<2>.
* hashlib: hashlib<5>.
* http.client: http client<2>.
* idlelib and IDLE: idlelib and IDLE<2>.
* importlib: importlib<6>.
* inspect: inspect<6>.
* json::
* logging: logging<4>.
* math: math<7>.
* multiprocessing: multiprocessing<5>.
* os: os<8>.
* pathlib: pathlib<9>.
* pdb: pdb<5>.
* pickle: pickle<2>.
* pickletools::
* pydoc: pydoc<3>.
* random: random<4>.
* re: re<5>.
* readline::
* rlcompleter::
* shlex: shlex<2>.
* site: site<3>.
* sqlite3: sqlite3<7>.
* socket: socket<7>.
* socketserver: socketserver<2>.
* ssl: ssl<7>.
* statistics: statistics<5>.
* struct::
* subprocess: subprocess<3>.
* sys: sys<10>.
* telnetlib::
* time: time<6>.
* timeit::
* tkinter: tkinter<6>.
* traceback: traceback<4>.
* tracemalloc: tracemalloc<3>.
* typing: typing<9>.
* unicodedata: unicodedata<7>.
* unittest.mock: unittest mock<2>.
* urllib.request: urllib request.
* urllib.robotparser: urllib robotparser.
* venv: venv<5>.
* warnings: warnings<4>.
* winreg::
* winsound::
* xmlrpc.client: xmlrpc client.
* zipfile: zipfile<3>.
* zlib::


File: python.info,  Node: array<4>,  Next: ast<4>,  Up: Improved Modules<8>

1.8.5.1 array
.............

Exhausted iterators of *note array.array: 1a0. will now stay exhausted
even if the iterated array is extended.  This is consistent with the
behavior of other mutable sequences.

Contributed by Serhiy Storchaka in bpo-26492(1).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26492


File: python.info,  Node: ast<4>,  Next: asyncio<9>,  Prev: array<4>,  Up: Improved Modules<8>

1.8.5.2 ast
...........

The new *note ast.Constant: 2b9. AST node has been added.  It can be
used by external AST optimizers for the purposes of constant folding.

Contributed by Victor Stinner in bpo-26146(1).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26146


File: python.info,  Node: asyncio<9>,  Next: binascii<2>,  Prev: ast<4>,  Up: Improved Modules<8>

1.8.5.3 asyncio
...............

Starting with Python 3.6 the ‘asyncio’ module is no longer provisional
and its API is considered stable.

Notable changes in the *note asyncio: a. module since Python 3.5.0 (all
backported to 3.5.x due to the provisional status):

   * The *note get_event_loop(): 2c2. function has been changed to
     always return the currently running loop when called from
     coroutines and callbacks.  (Contributed by Yury Selivanov in
     bpo-28613(1).)

   * The *note ensure_future(): c98. function and all functions that use
     it, such as *note loop.run_until_complete(): c99, now accept all
     kinds of *note awaitable objects: 1ad.  (Contributed by Yury
     Selivanov.)

   * New *note run_coroutine_threadsafe(): 889. function to submit
     coroutines to event loops from other threads.  (Contributed by
     Vincent Michel.)

   * New *note Transport.is_closing(): c9a. method to check if the
     transport is closing or closed.  (Contributed by Yury Selivanov.)

   * The *note loop.create_server(): b2c. method can now accept a list
     of hosts.  (Contributed by Yann Sionneau.)

   * New *note loop.create_future(): c9b. method to create Future
     objects.  This allows alternative event loop implementations, such
     as uvloop(2), to provide a faster *note asyncio.Future: bec.
     implementation.  (Contributed by Yury Selivanov in bpo-27041(3).)

   * New *note loop.get_exception_handler(): c9c. method to get the
     current exception handler.  (Contributed by Yury Selivanov in
     bpo-27040(4).)

   * New *note StreamReader.readuntil(): 1b4. method to read data from
     the stream until a separator bytes sequence appears.  (Contributed
     by Mark Korenberg.)

   * The performance of *note StreamReader.readexactly(): c9d. has been
     improved.  (Contributed by Mark Korenberg in bpo-28370(5).)

   * The *note loop.getaddrinfo(): c34. method is optimized to avoid
     calling the system ‘getaddrinfo’ function if the address is already
     resolved.  (Contributed by A. Jesse Jiryu Davis.)

   * The *note loop.stop(): c9e. method has been changed to stop the
     loop immediately after the current iteration.  Any new callbacks
     scheduled as a result of the last iteration will be discarded.
     (Contributed by Guido van Rossum in bpo-25593(6).)

   * *note Future.set_exception: c9f. will now raise *note TypeError:
     2c3. when passed an instance of the *note StopIteration: c1b.
     exception.  (Contributed by Chris Angelico in bpo-26221(7).)

   * New *note loop.connect_accepted_socket(): 7e2. method to be used by
     servers that accept connections outside of asyncio, but that use
     asyncio to handle them.  (Contributed by Jim Fulton in
     bpo-27392(8).)

   * ‘TCP_NODELAY’ flag is now set for all TCP transports by default.
     (Contributed by Yury Selivanov in bpo-27456(9).)

   * New *note loop.shutdown_asyncgens(): ca0. to properly close pending
     asynchronous generators before closing the loop.  (Contributed by
     Yury Selivanov in bpo-28003(10).)

   * *note Future: bec. and *note Task: 1be. classes now have an
     optimized C implementation which makes asyncio code up to 30%
     faster.  (Contributed by Yury Selivanov and INADA Naoki in
     bpo-26081(11) and bpo-28544(12).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28613

   (2) https://github.com/MagicStack/uvloop

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27041

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27040

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28370

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25593

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26221

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27392

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27456

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28003

   (11) https://bugs.python.org/issue?@action=redirect&bpo=26081

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28544


File: python.info,  Node: binascii<2>,  Next: cmath,  Prev: asyncio<9>,  Up: Improved Modules<8>

1.8.5.4 binascii
................

The *note b2a_base64(): ca2. function now accepts an optional 'newline'
keyword argument to control whether the newline character is appended to
the return value.  (Contributed by Victor Stinner in bpo-25357(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25357


File: python.info,  Node: cmath,  Next: collections<4>,  Prev: binascii<2>,  Up: Improved Modules<8>

1.8.5.5 cmath
.............

The new *note cmath.tau: ca4. ('τ') constant has been added.
(Contributed by Lisa Roach in bpo-12345(1), see PEP 628(2) for details.)

New constants: *note cmath.inf: ca5. and *note cmath.nan: ca6. to match
*note math.inf: ca7. and *note math.nan: 666, and also *note cmath.infj:
ca8. and *note cmath.nanj: ca9. to match the format used by complex
repr.  (Contributed by Mark Dickinson in bpo-23229(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12345

   (2) https://peps.python.org/pep-0628/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23229


File: python.info,  Node: collections<4>,  Next: concurrent futures<4>,  Prev: cmath,  Up: Improved Modules<8>

1.8.5.6 collections
...................

The new *note Collection: cab. abstract base class has been added to
represent sized iterable container classes.  (Contributed by Ivan
Levkivskyi, docs by Neil Girdhar in bpo-27598(1).)

The new *note Reversible: cac. abstract base class represents iterable
classes that also provide the *note __reversed__(): cad. method.
(Contributed by Ivan Levkivskyi in bpo-25987(2).)

The new *note AsyncGenerator: cae. abstract base class represents
asynchronous generators.  (Contributed by Yury Selivanov in
bpo-28720(3).)

The *note namedtuple(): 1ca. function now accepts an optional keyword
argument 'module', which, when specified, is used for the *note
__module__: 377. attribute of the returned named tuple class.
(Contributed by Raymond Hettinger in bpo-17941(4).)

The 'verbose' and 'rename' arguments for *note namedtuple(): 1ca. are
now keyword-only.  (Contributed by Raymond Hettinger in bpo-25628(5).)

Recursive *note collections.deque: 5df. instances can now be pickled.
(Contributed by Serhiy Storchaka in bpo-26482(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27598

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25987

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28720

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17941

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25628

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26482


File: python.info,  Node: concurrent futures<4>,  Next: contextlib<4>,  Prev: collections<4>,  Up: Improved Modules<8>

1.8.5.7 concurrent.futures
..........................

The *note ThreadPoolExecutor: 745. class constructor now accepts an
optional 'thread_name_prefix' argument to make it possible to customize
the names of the threads created by the pool.  (Contributed by Gregory
P.  Smith in bpo-27664(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27664


File: python.info,  Node: contextlib<4>,  Next: datetime<5>,  Prev: concurrent futures<4>,  Up: Improved Modules<8>

1.8.5.8 contextlib
..................

The *note contextlib.AbstractContextManager: cb1. class has been added
to provide an abstract base class for context managers.  It provides a
sensible default implementation for ‘__enter__()’ which returns ‘self’
and leaves ‘__exit__()’ an abstract method.  A matching class has been
added to the *note typing: 104. module as *note typing.ContextManager:
cb2.  (Contributed by Brett Cannon in bpo-25609(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25609


File: python.info,  Node: datetime<5>,  Next: decimal<2>,  Prev: contextlib<4>,  Up: Improved Modules<8>

1.8.5.9 datetime
................

The *note datetime: 1cc. and *note time: 1ce. classes have the new *note
fold: cb4. attribute used to disambiguate local time when necessary.
Many functions in the *note datetime: 30. have been updated to support
local time disambiguation.  See *note Local Time Disambiguation: c5d.
section for more information.  (Contributed by Alexander Belopolsky in
bpo-24773(1).)

The *note datetime.strftime(): cb5. and *note date.strftime(): cb6.
methods now support ISO 8601 date directives ‘%G’, ‘%u’ and ‘%V’.
(Contributed by Ashley Anderson in bpo-12006(2).)

The *note datetime.isoformat(): b48. function now accepts an optional
'timespec' argument that specifies the number of additional components
of the time value to include.  (Contributed by Alessandro Cucci and
Alexander Belopolsky in bpo-19475(3).)

The *note datetime.combine(): cb7. now accepts an optional 'tzinfo'
argument.  (Contributed by Alexander Belopolsky in bpo-27661(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24773

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12006

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19475

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27661


File: python.info,  Node: decimal<2>,  Next: distutils<5>,  Prev: datetime<5>,  Up: Improved Modules<8>

1.8.5.10 decimal
................

New *note Decimal.as_integer_ratio(): cb9. method that returns a pair
‘(n, d)’ of integers that represent the given *note Decimal: 29d.
instance as a fraction, in lowest terms and with a positive denominator:

     >>> Decimal('-3.14').as_integer_ratio()
     (-157, 50)

(Contributed by Stefan Krah amd Mark Dickinson in bpo-25928(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25928


File: python.info,  Node: distutils<5>,  Next: email<2>,  Prev: decimal<2>,  Up: Improved Modules<8>

1.8.5.11 distutils
..................

The ‘default_format’ attribute has been removed from
‘distutils.command.sdist.sdist’ and the ‘formats’ attribute defaults to
‘['gztar']’.  Although not anticipated, any code relying on the presence
of ‘default_format’ may need to be adapted.  See bpo-27819(1) for more
details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27819


File: python.info,  Node: email<2>,  Next: encodings<2>,  Prev: distutils<5>,  Up: Improved Modules<8>

1.8.5.12 email
..............

The new email API, enabled via the 'policy' keyword to various
constructors, is no longer provisional.  The *note email: 3b.
documentation has been reorganized and rewritten to focus on the new
API, while retaining the old documentation for the legacy API.
(Contributed by R. David Murray in bpo-24277(1).)

The *note email.mime: 45. classes now all accept an optional 'policy'
keyword.  (Contributed by Berker Peksag in bpo-27331(2).)

The *note DecodedGenerator: cbc. now supports the 'policy' keyword.

There is a new *note policy: 4f. attribute, *note message_factory: cbd,
that controls what class is used by default when the parser creates new
message objects.  For the *note email.policy.compat32: cbe. policy this
is *note Message: 27c, for the new policies it is *note EmailMessage:
27b.  (Contributed by R. David Murray in bpo-20476(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24277

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27331

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20476


File: python.info,  Node: encodings<2>,  Next: enum<7>,  Prev: email<2>,  Up: Improved Modules<8>

1.8.5.13 encodings
..................

On Windows, added the ‘'oem'’ encoding to use ‘CP_OEMCP’, and the
‘'ansi'’ alias for the existing ‘'mbcs'’ encoding, which uses the
‘CP_ACP’ code page.  (Contributed by Steve Dower in bpo-27959(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27959


File: python.info,  Node: enum<7>,  Next: faulthandler<2>,  Prev: encodings<2>,  Up: Improved Modules<8>

1.8.5.14 enum
.............

Two new enumeration base classes have been added to the *note enum: 56.
module: *note Flag: 626. and *note IntFlag: cc1.  Both are used to
define constants that can be combined using the bitwise operators.
(Contributed by Ethan Furman in bpo-23591(1).)

Many standard library modules have been updated to use the *note
IntFlag: cc1. class for their constants.

The new *note enum.auto: cc2. value can be used to assign values to enum
members automatically:

     >>> from enum import Enum, auto
     >>> class Color(Enum):
     ...     red = auto()
     ...     blue = auto()
     ...     green = auto()
     ...
     >>> list(Color)
     [<Color.red: 1>, <Color.blue: 2>, <Color.green: 3>]

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23591


File: python.info,  Node: faulthandler<2>,  Next: fileinput<2>,  Prev: enum<7>,  Up: Improved Modules<8>

1.8.5.15 faulthandler
.....................

On Windows, the *note faulthandler: 58. module now installs a handler
for Windows exceptions: see *note faulthandler.enable(): cc4.
(Contributed by Victor Stinner in bpo-23848(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23848


File: python.info,  Node: fileinput<2>,  Next: hashlib<5>,  Prev: faulthandler<2>,  Up: Improved Modules<8>

1.8.5.16 fileinput
..................

*note hook_encoded(): cc6. now supports the 'errors' argument.
(Contributed by Joseph Hackman in bpo-25788(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25788


File: python.info,  Node: hashlib<5>,  Next: http client<2>,  Prev: fileinput<2>,  Up: Improved Modules<8>

1.8.5.17 hashlib
................

*note hashlib: 68. supports OpenSSL 1.1.0.  The minimum recommend
version is 1.0.2.  (Contributed by Christian Heimes in bpo-26470(1).)

BLAKE2 hash functions were added to the module.  *note blake2b(): 645.
and *note blake2s(): 646. are always available and support the full
feature set of BLAKE2.  (Contributed by Christian Heimes in bpo-26798(2)
based on code by Dmitry Chestnykh and Samuel Neves.  Documentation
written by Dmitry Chestnykh.)

The SHA-3 hash functions *note sha3_224(): cc8, *note sha3_256(): cc9,
*note sha3_384(): cca, *note sha3_512(): ccb, and SHAKE hash functions
*note shake_128(): ccc. and *note shake_256(): ccd. were added.
(Contributed by Christian Heimes in bpo-16113(3).  Keccak Code Package
by Guido Bertoni, Joan Daemen, Michaël Peeters, Gilles Van Assche, and
Ronny Van Keer.)

The password-based key derivation function *note scrypt(): c5f. is now
available with OpenSSL 1.1.0 and newer.  (Contributed by Christian
Heimes in bpo-27928(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26470

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26798

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16113

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27928


File: python.info,  Node: http client<2>,  Next: idlelib and IDLE<2>,  Prev: hashlib<5>,  Up: Improved Modules<8>

1.8.5.18 http.client
....................

*note HTTPConnection.request(): ccf. and *note endheaders(): cd0. both
now support chunked encoding request bodies.  (Contributed by Demian
Brecht and Rolf Krahl in bpo-12319(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12319


File: python.info,  Node: idlelib and IDLE<2>,  Next: importlib<6>,  Prev: http client<2>,  Up: Improved Modules<8>

1.8.5.19 idlelib and IDLE
.........................

The idlelib package is being modernized and refactored to make IDLE look
and work better and to make the code easier to understand, test, and
improve.  Part of making IDLE look better, especially on Linux and Mac,
is using ttk widgets, mostly in the dialogs.  As a result, IDLE no
longer runs with tcl/tk 8.4.  It now requires tcl/tk 8.5 or 8.6.  We
recommend running the latest release of either.

‘Modernizing’ includes renaming and consolidation of idlelib modules.
The renaming of files with partial uppercase names is similar to the
renaming of, for instance, Tkinter and TkFont to tkinter and
tkinter.font in 3.0.  As a result, imports of idlelib files that worked
in 3.5 will usually not work in 3.6.  At least a module name change will
be needed (see idlelib/README.txt), sometimes more.  (Name changes
contributed by Al Swiegart and Terry Reedy in bpo-24225(1).  Most
idlelib patches since have been and will be part of the process.)

In compensation, the eventual result with be that some idlelib classes
will be easier to use, with better APIs and docstrings explaining them.
Additional useful information will be added to idlelib when available.

New in 3.6.2:

Multiple fixes for autocompletion.  (Contributed by Louie Lu in
bpo-15786(2).)

New in 3.6.3:

Module Browser (on the File menu, formerly called Class Browser), now
displays nested functions and classes in addition to top-level functions
and classes.  (Contributed by Guilherme Polo, Cheryl Sabella, and Terry
Jan Reedy in bpo-1612262(3).)

The IDLE features formerly implemented as extensions have been
reimplemented as normal features.  Their settings have been moved from
the Extensions tab to other dialog tabs.  (Contributed by Charles
Wohlganger and Terry Jan Reedy in bpo-27099(4).)

The Settings dialog (Options, Configure IDLE) has been partly rewritten
to improve both appearance and function.  (Contributed by Cheryl Sabella
and Terry Jan Reedy in multiple issues.)

New in 3.6.4:

The font sample now includes a selection of non-Latin characters so that
users can better see the effect of selecting a particular font.
(Contributed by Terry Jan Reedy in bpo-13802(5).)  The sample can be
edited to include other characters.  (Contributed by Serhiy Storchaka in
bpo-31860(6).)

New in 3.6.6:

Editor code context option revised.  Box displays all context lines up
to maxlines.  Clicking on a context line jumps the editor to that line.
Context colors for custom themes is added to Highlights tab of Settings
dialog.  (Contributed by Cheryl Sabella and Terry Jan Reedy in
bpo-33642(7), bpo-33768(8), and bpo-33679(9).)

On Windows, a new API call tells Windows that tk scales for DPI. On
Windows 8.1+ or 10, with DPI compatibility properties of the Python
binary unchanged, and a monitor resolution greater than 96 DPI, this
should make text and lines sharper.  It should otherwise have no effect.
(Contributed by Terry Jan Reedy in bpo-33656(10).)

New in 3.6.7:

Output over N lines (50 by default) is squeezed down to a button.  N can
be changed in the PyShell section of the General page of the Settings
dialog.  Fewer, but possibly extra long, lines can be squeezed by right
clicking on the output.  Squeezed output can be expanded in place by
double-clicking the button or into the clipboard or a separate window by
right-clicking the button.  (Contributed by Tal Einat in
bpo-1529353(11).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24225

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15786

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1612262

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27099

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13802

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31860

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33642

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33768

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33679

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33656

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1529353


File: python.info,  Node: importlib<6>,  Next: inspect<6>,  Prev: idlelib and IDLE<2>,  Up: Improved Modules<8>

1.8.5.20 importlib
..................

Import now raises the new exception *note ModuleNotFoundError: b61.
(subclass of *note ImportError: 41c.) when it cannot find a module.
Code that current checks for ‘ImportError’ (in try-except) will still
work.  (Contributed by Eric Snow in bpo-15767(1).)

*note importlib.util.LazyLoader: cd3. now calls *note create_module():
cd4. on the wrapped loader, removing the restriction that *note
importlib.machinery.BuiltinImporter: cd5. and *note
importlib.machinery.ExtensionFileLoader: cd6. couldn’t be used with
‘importlib.util.LazyLoader’.

*note importlib.util.cache_from_source(): 2fe, *note
importlib.util.source_from_cache(): 51d, and *note
importlib.util.spec_from_file_location(): cd7. now accept a *note
path-like object: 2a0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15767


File: python.info,  Node: inspect<6>,  Next: json,  Prev: importlib<6>,  Up: Improved Modules<8>

1.8.5.21 inspect
................

The *note inspect.signature(): 73b. function now reports the implicit
‘.0’ parameters generated by the compiler for comprehension and
generator expression scopes as if they were positional-only parameters
called ‘implicit0’.  (Contributed by Jelle Zijlstra in bpo-19611(1).)

To reduce code churn when upgrading from Python 2.7 and the legacy
‘inspect.getargspec()’ API, the previously documented deprecation of
*note inspect.getfullargspec(): 73c. has been reversed.  While this
function is convenient for single/source Python 2/3 code bases, the
richer *note inspect.signature(): 73b. interface remains the recommended
approach for new code.  (Contributed by Nick Coghlan in bpo-27172(2))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19611

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27172


File: python.info,  Node: json,  Next: logging<4>,  Prev: inspect<6>,  Up: Improved Modules<8>

1.8.5.22 json
.............

*note json.load(): cda. and *note json.loads(): 95f. now support binary
input.  Encoded JSON should be represented using either UTF-8, UTF-16,
or UTF-32.  (Contributed by Serhiy Storchaka in bpo-17909(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17909


File: python.info,  Node: logging<4>,  Next: math<7>,  Prev: json,  Up: Improved Modules<8>

1.8.5.23 logging
................

The new *note WatchedFileHandler.reopenIfNeeded(): cdc. method has been
added to add the ability to check if the log file needs to be reopened.
(Contributed by Marian Horban in bpo-24884(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24884


File: python.info,  Node: math<7>,  Next: multiprocessing<5>,  Prev: logging<4>,  Up: Improved Modules<8>

1.8.5.24 math
.............

The tau ('τ') constant has been added to the *note math: 8e. and *note
cmath: 18. modules.  (Contributed by Lisa Roach in bpo-12345(1), see PEP
628(2) for details.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12345

   (2) https://peps.python.org/pep-0628/


File: python.info,  Node: multiprocessing<5>,  Next: os<8>,  Prev: math<7>,  Up: Improved Modules<8>

1.8.5.25 multiprocessing
........................

*note Proxy Objects: cdf. returned by *note multiprocessing.Manager():
ce0. can now be nested.  (Contributed by Davin Potts in bpo-6766(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6766


File: python.info,  Node: os<8>,  Next: pathlib<9>,  Prev: multiprocessing<5>,  Up: Improved Modules<8>

1.8.5.26 os
...........

See the summary of *note PEP 519: c5c. for details on how the *note os:
a1. and *note os.path: a2. modules now support *note path-like objects:
2a0.

*note scandir(): a6d. now supports *note bytes: 1c2. paths on Windows.

A new *note close(): ce2. method allows explicitly closing a *note
scandir(): a6d. iterator.  The ‘scandir()’ iterator now supports the
*note context manager: 5d7. protocol.  If a ‘scandir()’ iterator is
neither exhausted nor explicitly closed a *note ResourceWarning: 244.
will be emitted in its destructor.  (Contributed by Serhiy Storchaka in
bpo-25994(1).)

On Linux, *note os.urandom(): 526. now blocks until the system urandom
entropy pool is initialized to increase the security.  See the PEP
524(2) for the rationale.

The Linux ‘getrandom()’ syscall (get random bytes) is now exposed as the
new *note os.getrandom(): ce3. function.  (Contributed by Victor
Stinner, part of the PEP 524(3))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25994

   (2) https://peps.python.org/pep-0524/

   (3) https://peps.python.org/pep-0524/


File: python.info,  Node: pathlib<9>,  Next: pdb<5>,  Prev: os<8>,  Up: Improved Modules<8>

1.8.5.27 pathlib
................

*note pathlib: a4. now supports *note path-like objects: 2a0.
(Contributed by Brett Cannon in bpo-27186(1).)

See the summary of *note PEP 519: c5c. for details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27186


File: python.info,  Node: pdb<5>,  Next: pickle<2>,  Prev: pathlib<9>,  Up: Improved Modules<8>

1.8.5.28 pdb
............

The *note Pdb: 92b. class constructor has a new optional 'readrc'
argument to control whether ‘.pdbrc’ files should be read.


File: python.info,  Node: pickle<2>,  Next: pickletools,  Prev: pdb<5>,  Up: Improved Modules<8>

1.8.5.29 pickle
...............

Objects that need ‘__new__’ called with keyword arguments can now be
pickled using *note pickle protocols: ce7. older than protocol version
4.  Protocol version 4 already supports this case.  (Contributed by
Serhiy Storchaka in bpo-24164(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24164


File: python.info,  Node: pickletools,  Next: pydoc<3>,  Prev: pickle<2>,  Up: Improved Modules<8>

1.8.5.30 pickletools
....................

*note pickletools.dis(): ce9. now outputs the implicit memo index for
the ‘MEMOIZE’ opcode.  (Contributed by Serhiy Storchaka in
bpo-25382(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25382


File: python.info,  Node: pydoc<3>,  Next: random<4>,  Prev: pickletools,  Up: Improved Modules<8>

1.8.5.31 pydoc
..............

The *note pydoc: b5. module has learned to respect the ‘MANPAGER’
environment variable.  (Contributed by Matthias Klose in bpo-8637(1).)

*note help(): 8e0. and *note pydoc: b5. can now list named tuple fields
in the order they were defined rather than alphabetically.  (Contributed
by Raymond Hettinger in bpo-24879(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8637

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24879


File: python.info,  Node: random<4>,  Next: re<5>,  Prev: pydoc<3>,  Up: Improved Modules<8>

1.8.5.32 random
...............

The new *note choices(): cec. function returns a list of elements of
specified size from the given population with optional weights.
(Contributed by Raymond Hettinger in bpo-18844(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18844


File: python.info,  Node: re<5>,  Next: readline,  Prev: random<4>,  Up: Improved Modules<8>

1.8.5.33 re
...........

Added support of modifier spans in regular expressions.  Examples:
‘'(?i:p)ython'’ matches ‘'python'’ and ‘'Python'’, but not ‘'PYTHON'’;
‘'(?i)g(?-i:v)r'’ matches ‘'GvR'’ and ‘'gvr'’, but not ‘'GVR'’.
(Contributed by Serhiy Storchaka in bpo-433028(1).)

Match object groups can be accessed by ‘__getitem__’, which is
equivalent to ‘group()’.  So ‘mo['name']’ is now equivalent to
‘mo.group('name')’.  (Contributed by Eric Smith in bpo-24454(2).)

*note Match: cee. objects now support *note index-like objects: 720. as
group indices.  (Contributed by Jeroen Demeyer and Xiang Zhang in
bpo-27177(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=433028

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24454

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27177


File: python.info,  Node: readline,  Next: rlcompleter,  Prev: re<5>,  Up: Improved Modules<8>

1.8.5.34 readline
.................

Added *note set_auto_history(): cf0. to enable or disable automatic
addition of input to the history list.  (Contributed by Tyler Crompton
in bpo-26870(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26870


File: python.info,  Node: rlcompleter,  Next: shlex<2>,  Prev: readline,  Up: Improved Modules<8>

1.8.5.35 rlcompleter
....................

Private and special attribute names now are omitted unless the prefix
starts with underscores.  A space or a colon is added after some
completed keywords.  (Contributed by Serhiy Storchaka in bpo-25011(1)
and bpo-25209(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25011

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25209


File: python.info,  Node: shlex<2>,  Next: site<3>,  Prev: rlcompleter,  Up: Improved Modules<8>

1.8.5.36 shlex
..............

The *note shlex: cf3. has much *note improved shell compatibility: cf4.
through the new 'punctuation_chars' argument to control which characters
are treated as punctuation.  (Contributed by Vinay Sajip in
bpo-1521950(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1521950


File: python.info,  Node: site<3>,  Next: sqlite3<7>,  Prev: shlex<2>,  Up: Improved Modules<8>

1.8.5.37 site
.............

When specifying paths to add to *note sys.path: 3b7. in a ‘.pth’ file,
you may now specify file paths on top of directories (e.g.  zip files).
(Contributed by Wolfgang Langner in bpo-26587(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26587


File: python.info,  Node: sqlite3<7>,  Next: socket<7>,  Prev: site<3>,  Up: Improved Modules<8>

1.8.5.38 sqlite3
................

*note sqlite3.Cursor.lastrowid: cf7. now supports the ‘REPLACE’
statement.  (Contributed by Alex LordThorsen in bpo-16864(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16864


File: python.info,  Node: socket<7>,  Next: socketserver<2>,  Prev: sqlite3<7>,  Up: Improved Modules<8>

1.8.5.39 socket
...............

The *note ioctl(): cf9. function now supports the *note
SIO_LOOPBACK_FAST_PATH: cfa. control code.  (Contributed by Daniel
Stokes in bpo-26536(1).)

The *note getsockopt(): cfb. constants ‘SO_DOMAIN’, ‘SO_PROTOCOL’,
‘SO_PEERSEC’, and ‘SO_PASSSEC’ are now supported.  (Contributed by
Christian Heimes in bpo-26907(2).)

The *note setsockopt(): cfc. now supports the ‘setsockopt(level,
optname, None, optlen: int)’ form.  (Contributed by Christian Heimes in
bpo-27744(3).)

The socket module now supports the address family *note AF_ALG: cfd. to
interface with Linux Kernel crypto API. ‘ALG_*’, ‘SOL_ALG’ and *note
sendmsg_afalg(): cfe. were added.  (Contributed by Christian Heimes in
bpo-27744(4) with support from Victor Stinner.)

New Linux constants ‘TCP_USER_TIMEOUT’ and ‘TCP_CONGESTION’ were added.
(Contributed by Omar Sandoval, bpo-26273(5)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26536

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26907

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27744

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27744

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26273


File: python.info,  Node: socketserver<2>,  Next: ssl<7>,  Prev: socket<7>,  Up: Improved Modules<8>

1.8.5.40 socketserver
.....................

Servers based on the *note socketserver: cd. module, including those
defined in *note http.server: 72, *note xmlrpc.server: 12f. and *note
wsgiref.simple_server: 11b, now support the *note context manager: 5d7.
protocol.  (Contributed by Aviv Palivoda in bpo-26404(1).)

The *note wfile: d00. attribute of *note StreamRequestHandler: d01.
classes now implements the *note io.BufferedIOBase: 697. writable
interface.  In particular, calling *note write(): d02. is now guaranteed
to send the data in full.  (Contributed by Martin Panter in
bpo-26721(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26404

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26721


File: python.info,  Node: ssl<7>,  Next: statistics<5>,  Prev: socketserver<2>,  Up: Improved Modules<8>

1.8.5.41 ssl
............

*note ssl: d0. supports OpenSSL 1.1.0.  The minimum recommend version is
1.0.2.  (Contributed by Christian Heimes in bpo-26470(1).)

3DES has been removed from the default cipher suites and ChaCha20
Poly1305 cipher suites have been added.  (Contributed by Christian
Heimes in bpo-27850(2) and bpo-27766(3).)

*note SSLContext: 294. has better default configuration for options and
ciphers.  (Contributed by Christian Heimes in bpo-28043(4).)

SSL session can be copied from one client-side connection to another
with the new *note SSLSession: d04. class.  TLS session resumption can
speed up the initial handshake, reduce latency and improve performance
(Contributed by Christian Heimes in bpo-19500(5) based on a draft by
Alex Warhawk.)

The new *note get_ciphers(): d05. method can be used to get a list of
enabled ciphers in order of cipher priority.

All constants and flags have been converted to *note IntEnum: d06. and
*note IntFlag: cc1.  (Contributed by Christian Heimes in bpo-28025(6).)

Server and client-side specific TLS protocols for *note SSLContext: 294.
were added.  (Contributed by Christian Heimes in bpo-28085(7).)

Added *note ssl.SSLContext.post_handshake_auth: a3e. to enable and *note
ssl.SSLSocket.verify_client_post_handshake(): a3f. to initiate TLS 1.3
post-handshake authentication.  (Contributed by Christian Heimes in
gh-78851(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26470

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27850

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27766

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28043

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19500

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28025

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28085

   (8) https://github.com/python/cpython/issues/78851


File: python.info,  Node: statistics<5>,  Next: struct,  Prev: ssl<7>,  Up: Improved Modules<8>

1.8.5.42 statistics
...................

A new *note harmonic_mean(): d08. function has been added.  (Contributed
by Steven D’Aprano in bpo-27181(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27181


File: python.info,  Node: struct,  Next: subprocess<3>,  Prev: statistics<5>,  Up: Improved Modules<8>

1.8.5.43 struct
...............

*note struct: d5. now supports IEEE 754 half-precision floats via the
‘'e'’ format specifier.  (Contributed by Eli Stevens, Mark Dickinson in
bpo-11734(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11734


File: python.info,  Node: subprocess<3>,  Next: sys<10>,  Prev: struct,  Up: Improved Modules<8>

1.8.5.44 subprocess
...................

*note subprocess.Popen: 199. destructor now emits a *note
ResourceWarning: 244. warning if the child process is still running.
Use the context manager protocol (‘with proc: ...’) or explicitly call
the *note wait(): d0b. method to read the exit status of the child
process.  (Contributed by Victor Stinner in bpo-26741(1).)

The *note subprocess.Popen: 199. constructor and all functions that pass
arguments through to it now accept 'encoding' and 'errors' arguments.
Specifying either of these will enable text mode for the 'stdin',
'stdout' and 'stderr' streams.  (Contributed by Steve Dower in
bpo-6135(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26741

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6135


File: python.info,  Node: sys<10>,  Next: telnetlib,  Prev: subprocess<3>,  Up: Improved Modules<8>

1.8.5.45 sys
............

The new *note getfilesystemencodeerrors(): d0d. function returns the
name of the error mode used to convert between Unicode filenames and
bytes filenames.  (Contributed by Steve Dower in bpo-27781(1).)

On Windows the return value of the *note getwindowsversion(): d0e.
function now includes the 'platform_version' field which contains the
accurate major version, minor version and build number of the current
operating system, rather than the version that is being emulated for the
process (Contributed by Steve Dower in bpo-27932(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27781

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27932


File: python.info,  Node: telnetlib,  Next: time<6>,  Prev: sys<10>,  Up: Improved Modules<8>

1.8.5.46 telnetlib
..................

‘telnetlib.Telnet’ is now a context manager (contributed by Stéphane
Wirtel in bpo-25485(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25485


File: python.info,  Node: time<6>,  Next: timeit,  Prev: telnetlib,  Up: Improved Modules<8>

1.8.5.47 time
.............

The *note struct_time: d11. attributes ‘tm_gmtoff’ and ‘tm_zone’ are now
available on all platforms.


File: python.info,  Node: timeit,  Next: tkinter<6>,  Prev: time<6>,  Up: Improved Modules<8>

1.8.5.48 timeit
...............

The new *note Timer.autorange(): d13. convenience method has been added
to call *note Timer.timeit(): d14. repeatedly so that the total run time
is greater or equal to 200 milliseconds.  (Contributed by Steven
D’Aprano in bpo-6422(1).)

*note timeit: ef. now warns when there is substantial (4x) variance
between best and worst times.  (Contributed by Serhiy Storchaka in
bpo-23552(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6422

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23552


File: python.info,  Node: tkinter<6>,  Next: traceback<4>,  Prev: timeit,  Up: Improved Modules<8>

1.8.5.49 tkinter
................

Added methods ‘Variable.trace_add()’, ‘Variable.trace_remove()’ and
‘trace_info()’ in the ‘tkinter.Variable’ class.  They replace old
methods ‘trace_variable()’, ‘trace()’, ‘trace_vdelete()’ and
‘trace_vinfo()’ that use obsolete Tcl commands and might not work in
future versions of Tcl.  (Contributed by Serhiy Storchaka in
bpo-22115(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22115


File: python.info,  Node: traceback<4>,  Next: tracemalloc<3>,  Prev: tkinter<6>,  Up: Improved Modules<8>

1.8.5.50 traceback
..................

Both the traceback module and the interpreter’s builtin exception
display now abbreviate long sequences of repeated lines in tracebacks as
shown in the following example:

     >>> def f(): f()
     ...
     >>> f()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 1, in f
       File "<stdin>", line 1, in f
       File "<stdin>", line 1, in f
       [Previous line repeated 995 more times]
     RecursionError: maximum recursion depth exceeded

(Contributed by Emanuel Barry in bpo-26823(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26823


File: python.info,  Node: tracemalloc<3>,  Next: typing<9>,  Prev: traceback<4>,  Up: Improved Modules<8>

1.8.5.51 tracemalloc
....................

The *note tracemalloc: ff. module now supports tracing memory
allocations in multiple different address spaces.

The new *note DomainFilter: d18. filter class has been added to filter
block traces by their address space (domain).

(Contributed by Victor Stinner in bpo-26588(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26588


File: python.info,  Node: typing<9>,  Next: unicodedata<7>,  Prev: tracemalloc<3>,  Up: Improved Modules<8>

1.8.5.52 typing
...............

Since the *note typing: 104. module is *note provisional: b1c, all
changes introduced in Python 3.6 have also been backported to Python
3.5.x.

The *note typing: 104. module has a much improved support for generic
type aliases.  For example ‘Dict[str, Tuple[S, T]]’ is now a valid type
annotation.  (Contributed by Guido van Rossum in Github #195(1).)

The *note typing.ContextManager: cb2. class has been added for
representing *note contextlib.AbstractContextManager: cb1.  (Contributed
by Brett Cannon in bpo-25609(2).)

The *note typing.Collection: d1a. class has been added for representing
*note collections.abc.Collection: cab.  (Contributed by Ivan Levkivskyi
in bpo-27598(3).)

The *note typing.ClassVar: 266. type construct has been added to mark
class variables.  As introduced in PEP 526(4), a variable annotation
wrapped in ClassVar indicates that a given attribute is intended to be
used as a class variable and should not be set on instances of that
class.  (Contributed by Ivan Levkivskyi in Github #280(5).)

A new *note TYPE_CHECKING: d1b. constant that is assumed to be ‘True’ by
the static type checkers, but is ‘False’ at runtime.  (Contributed by
Guido van Rossum in Github #230(6).)

A new *note NewType(): d1c. helper function has been added to create
lightweight distinct types for annotations:

     from typing import NewType

     UserId = NewType('UserId', int)
     some_id = UserId(524313)

The static type checker will treat the new type as if it were a subclass
of the original type.  (Contributed by Ivan Levkivskyi in Github
#189(7).)

   ---------- Footnotes ----------

   (1) https://github.com/python/typing/pull/195

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25609

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27598

   (4) https://peps.python.org/pep-0526/

   (5) https://github.com/python/typing/pull/280

   (6) https://github.com/python/typing/issues/230

   (7) https://github.com/python/typing/issues/189


File: python.info,  Node: unicodedata<7>,  Next: unittest mock<2>,  Prev: typing<9>,  Up: Improved Modules<8>

1.8.5.53 unicodedata
....................

The *note unicodedata: 105. module now uses data from Unicode 9.0.0(1).
(Contributed by Benjamin Peterson.)

   ---------- Footnotes ----------

   (1) https://unicode.org/versions/Unicode9.0.0/


File: python.info,  Node: unittest mock<2>,  Next: urllib request,  Prev: unicodedata<7>,  Up: Improved Modules<8>

1.8.5.54 unittest.mock
......................

The *note Mock: a58. class has the following improvements:

   * Two new methods, *note Mock.assert_called(): d1f. and *note
     Mock.assert_called_once(): d20. to check if the mock object was
     called.  (Contributed by Amit Saha in bpo-26323(1).)

   * The *note Mock.reset_mock(): d21. method now has two optional
     keyword only arguments: 'return_value' and 'side_effect'.
     (Contributed by Kushal Das in bpo-21271(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26323

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21271


File: python.info,  Node: urllib request,  Next: urllib robotparser,  Prev: unittest mock<2>,  Up: Improved Modules<8>

1.8.5.55 urllib.request
.......................

If a HTTP request has a file or iterable body (other than a bytes
object) but no ‘Content-Length’ header, rather than throwing an error,
*note AbstractHTTPHandler: d23. now falls back to use chunked transfer
encoding.  (Contributed by Demian Brecht and Rolf Krahl in
bpo-12319(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12319


File: python.info,  Node: urllib robotparser,  Next: venv<5>,  Prev: urllib request,  Up: Improved Modules<8>

1.8.5.56 urllib.robotparser
...........................

*note RobotFileParser: d25. now supports the ‘Crawl-delay’ and
‘Request-rate’ extensions.  (Contributed by Nikolay Bogoychev in
bpo-16099(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16099


File: python.info,  Node: venv<5>,  Next: warnings<4>,  Prev: urllib robotparser,  Up: Improved Modules<8>

1.8.5.57 venv
.............

*note venv: 111. accepts a new parameter ‘--prompt’.  This parameter
provides an alternative prefix for the virtual environment.  (Proposed
by Łukasz Balcerzak and ported to 3.6 by Stéphane Wirtel in
bpo-22829(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22829


File: python.info,  Node: warnings<4>,  Next: winreg,  Prev: venv<5>,  Up: Improved Modules<8>

1.8.5.58 warnings
.................

A new optional 'source' parameter has been added to the *note
warnings.warn_explicit(): d28. function: the destroyed object which
emitted a *note ResourceWarning: 244.  A 'source' attribute has also
been added to ‘warnings.WarningMessage’ (contributed by Victor Stinner
in bpo-26568(1) and bpo-26567(2)).

When a *note ResourceWarning: 244. warning is logged, the *note
tracemalloc: ff. module is now used to try to retrieve the traceback
where the destroyed object was allocated.

Example with the script ‘example.py’:

     import warnings

     def func():
         return open(__file__)

     f = func()
     f = None

Output of the command ‘python3.6 -Wd -X tracemalloc=5 example.py’:

     example.py:7: ResourceWarning: unclosed file <_io.TextIOWrapper name='example.py' mode='r' encoding='UTF-8'>
       f = None
     Object allocated at (most recent call first):
       File "example.py", lineno 4
         return open(__file__)
       File "example.py", lineno 6
         f = func()

The “Object allocated at” traceback is new and is only displayed if
*note tracemalloc: ff. is tracing Python memory allocations and if the
*note warnings: 112. module was already imported.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26568

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26567


File: python.info,  Node: winreg,  Next: winsound,  Prev: warnings<4>,  Up: Improved Modules<8>

1.8.5.59 winreg
...............

Added the 64-bit integer type *note REG_QWORD: d2a.  (Contributed by
Clement Rouault in bpo-23026(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23026


File: python.info,  Node: winsound,  Next: xmlrpc client,  Prev: winreg,  Up: Improved Modules<8>

1.8.5.60 winsound
.................

Allowed keyword arguments to be passed to *note Beep: d2c, *note
MessageBeep: d2d, and *note PlaySound: d2e. (bpo-27982(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27982


File: python.info,  Node: xmlrpc client,  Next: zipfile<3>,  Prev: winsound,  Up: Improved Modules<8>

1.8.5.61 xmlrpc.client
......................

The *note xmlrpc.client: 12e. module now supports unmarshalling
additional data types used by the Apache XML-RPC implementation for
numerics and ‘None’.  (Contributed by Serhiy Storchaka in bpo-26885(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26885


File: python.info,  Node: zipfile<3>,  Next: zlib,  Prev: xmlrpc client,  Up: Improved Modules<8>

1.8.5.62 zipfile
................

A new *note ZipInfo.from_file(): d31. class method allows making a *note
ZipInfo: d32. instance from a filesystem file.  A new *note
ZipInfo.is_dir(): d33. method can be used to check if the ‘ZipInfo’
instance represents a directory.  (Contributed by Thomas Kluyver in
bpo-26039(1).)

The *note ZipFile.open(): 41e. method can now be used to write data into
a ZIP file, as well as for extracting data.  (Contributed by Thomas
Kluyver in bpo-26039(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26039

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26039


File: python.info,  Node: zlib,  Prev: zipfile<3>,  Up: Improved Modules<8>

1.8.5.63 zlib
.............

The *note compress(): 642. and *note decompress(): d35. functions now
accept keyword arguments.  (Contributed by Aviv Palivoda in bpo-26243(1)
and Xiang Zhang in bpo-16764(2) respectively.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26243

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16764


File: python.info,  Node: Optimizations<8>,  Next: Build and C API Changes<2>,  Prev: Improved Modules<8>,  Up: What’s New In Python 3 6

1.8.6 Optimizations
-------------------

   * The Python interpreter now uses a 16-bit wordcode instead of
     bytecode which made a number of opcode optimizations possible.
     (Contributed by Demur Rumed with input and reviews from Serhiy
     Storchaka and Victor Stinner in bpo-26647(1) and bpo-28050(2).)

   * The *note asyncio.Future: bec. class now has an optimized C
     implementation.  (Contributed by Yury Selivanov and INADA Naoki in
     bpo-26081(3).)

   * The *note asyncio.Task: 1be. class now has an optimized C
     implementation.  (Contributed by Yury Selivanov in bpo-28544(4).)

   * Various implementation improvements in the *note typing: 104.
     module (such as caching of generic types) allow up to 30 times
     performance improvements and reduced memory footprint.

   * The ASCII decoder is now up to 60 times as fast for error handlers
     ‘surrogateescape’, ‘ignore’ and ‘replace’ (Contributed by Victor
     Stinner in bpo-24870(5)).

   * The ASCII and the Latin1 encoders are now up to 3 times as fast for
     the error handler ‘surrogateescape’ (Contributed by Victor Stinner
     in bpo-25227(6)).

   * The UTF-8 encoder is now up to 75 times as fast for error handlers
     ‘ignore’, ‘replace’, ‘surrogateescape’, ‘surrogatepass’
     (Contributed by Victor Stinner in bpo-25267(7)).

   * The UTF-8 decoder is now up to 15 times as fast for error handlers
     ‘ignore’, ‘replace’ and ‘surrogateescape’ (Contributed by Victor
     Stinner in bpo-25301(8)).

   * ‘bytes % args’ is now up to 2 times faster.  (Contributed by Victor
     Stinner in bpo-25349(9)).

   * ‘bytearray % args’ is now between 2.5 and 5 times faster.
     (Contributed by Victor Stinner in bpo-25399(10)).

   * Optimize *note bytes.fromhex(): b08. and *note bytearray.fromhex():
     b09.: they are now between 2x and 3.5x faster.  (Contributed by
     Victor Stinner in bpo-25401(11)).

   * Optimize ‘bytes.replace(b'', b'.')’ and ‘bytearray.replace(b'',
     b'.')’: up to 80% faster.  (Contributed by Josh Snider in
     bpo-26574(12)).

   * Allocator functions of the *note PyMem_Malloc(): c87. domain (*note
     PYMEM_DOMAIN_MEM: c8a.) now use the *note pymalloc memory
     allocator: d37. instead of ‘malloc()’ function of the C library.
     The pymalloc allocator is optimized for objects smaller or equal to
     512 bytes with a short lifetime, and use ‘malloc()’ for larger
     memory blocks.  (Contributed by Victor Stinner in bpo-26249(13)).

   * *note pickle.load(): d38. and *note pickle.loads(): d39. are now up
     to 10% faster when deserializing many small objects (Contributed by
     Victor Stinner in bpo-27056(14)).

   * Passing *note keyword arguments: d3a. to a function has an overhead
     in comparison with passing *note positional arguments: d3b.  Now in
     extension functions implemented with using Argument Clinic this
     overhead is significantly decreased.  (Contributed by Serhiy
     Storchaka in bpo-27574(15)).

   * Optimized *note glob(): 29f. and *note iglob(): 80d. functions in
     the *note glob: 64. module; they are now about 3–6 times faster.
     (Contributed by Serhiy Storchaka in bpo-25596(16)).

   * Optimized globbing in *note pathlib: a4. by using *note
     os.scandir(): a6d.; it is now about 1.5–4 times faster.
     (Contributed by Serhiy Storchaka in bpo-26032(17)).

   * *note xml.etree.ElementTree: 125. parsing, iteration and deepcopy
     performance has been significantly improved.  (Contributed by
     Serhiy Storchaka in bpo-25638(18), bpo-25873(19), and
     bpo-25869(20).)

   * Creation of *note fractions.Fraction: 1e7. instances from floats
     and decimals is now 2 to 3 times faster.  (Contributed by Serhiy
     Storchaka in bpo-25971(21).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26647

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28050

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26081

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28544

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24870

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25227

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25267

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25301

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25349

   (10) https://bugs.python.org/issue?@action=redirect&bpo=25399

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25401

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26574

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26249

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27056

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27574

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25596

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26032

   (18) https://bugs.python.org/issue?@action=redirect&bpo=25638

   (19) https://bugs.python.org/issue?@action=redirect&bpo=25873

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25869

   (21) https://bugs.python.org/issue?@action=redirect&bpo=25971


File: python.info,  Node: Build and C API Changes<2>,  Next: Other Improvements,  Prev: Optimizations<8>,  Up: What’s New In Python 3 6

1.8.7 Build and C API Changes
-----------------------------

   * Python now requires some C99 support in the toolchain to build.
     Most notably, Python now uses standard integer types and macros in
     place of custom macros like ‘PY_LONG_LONG’.  For more information,
     see PEP 7(1) and bpo-17884(2).

   * Cross-compiling CPython with the Android NDK and the Android API
     level set to 21 (Android 5.0 Lollipop) or greater runs
     successfully.  While Android is not yet a supported platform, the
     Python test suite runs on the Android emulator with only about 16
     tests failures.  See the Android meta-issue bpo-26865(3).

   * The ‘--enable-optimizations’ configure flag has been added.
     Turning it on will activate expensive optimizations like PGO.
     (Original patch by Alecsandru Patrascu of Intel in bpo-26359(4).)

   * The *note GIL: 148. must now be held when allocator functions of
     *note PYMEM_DOMAIN_OBJ: c88. (ex: *note PyObject_Malloc(): c89.)
     and *note PYMEM_DOMAIN_MEM: c8a. (ex: *note PyMem_Malloc(): c87.)
     domains are called.

   * New *note Py_FinalizeEx(): d3d. API which indicates if flushing
     buffered data failed.  (Contributed by Martin Panter in
     bpo-5319(5).)

   * *note PyArg_ParseTupleAndKeywords(): 386. now supports *note
     positional-only parameters: a94.  Positional-only parameters are
     defined by empty names.  (Contributed by Serhiy Storchaka in
     bpo-26282(6)).

   * ‘PyTraceback_Print’ method now abbreviates long sequences of
     repeated lines as ‘"[Previous line repeated {count} more times]"’.
     (Contributed by Emanuel Barry in bpo-26823(7).)

   * The new *note PyErr_SetImportErrorSubclass(): d3e. function allows
     for specifying a subclass of *note ImportError: 41c. to raise.
     (Contributed by Eric Snow in bpo-15767(8).)

   * The new *note PyErr_ResourceWarning(): d3f. function can be used to
     generate a *note ResourceWarning: 244. providing the source of the
     resource allocation.  (Contributed by Victor Stinner in
     bpo-26567(9).)

   * The new *note PyOS_FSPath(): d40. function returns the file system
     representation of a *note path-like object: 2a0.  (Contributed by
     Brett Cannon in bpo-27186(10).)

   * The *note PyUnicode_FSConverter(): d41. and *note
     PyUnicode_FSDecoder(): 57a. functions will now accept *note
     path-like objects: 2a0.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0007/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17884

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26865

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (5) https://bugs.python.org/issue?@action=redirect&bpo=5319

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26282

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26823

   (8) https://bugs.python.org/issue?@action=redirect&bpo=15767

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26567

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27186


File: python.info,  Node: Other Improvements,  Next: Deprecated<9>,  Prev: Build and C API Changes<2>,  Up: What’s New In Python 3 6

1.8.8 Other Improvements
------------------------

   * When *note -version: d43. (short form: *note -V: 177.) is supplied
     twice, Python prints *note sys.version: 178. for detailed
     information.

          $ ./python -VV
          Python 3.6.0b4+ (3.6:223967b49e49+, Nov 21 2016, 20:55:04)
          [GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]


File: python.info,  Node: Deprecated<9>,  Next: Removed<9>,  Prev: Other Improvements,  Up: What’s New In Python 3 6

1.8.9 Deprecated
----------------

* Menu:

* New Keywords::
* Deprecated Python behavior::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<2>.
* xml: xml<6>.
* Deprecated functions and types of the C API: Deprecated functions and types of the C API<2>.
* Deprecated Build Options::


File: python.info,  Node: New Keywords,  Next: Deprecated Python behavior,  Up: Deprecated<9>

1.8.9.1 New Keywords
....................

‘async’ and ‘await’ are not recommended to be used as variable, class,
function or module names.  Introduced by PEP 492(1) in Python 3.5, they
will become proper keywords in Python 3.7.  Starting in Python 3.6, the
use of ‘async’ or ‘await’ as names will generate a *note
DeprecationWarning: 1a5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/


File: python.info,  Node: Deprecated Python behavior,  Next: Deprecated Python modules functions and methods<2>,  Prev: New Keywords,  Up: Deprecated<9>

1.8.9.2 Deprecated Python behavior
..................................

Raising the *note StopIteration: c1b. exception inside a generator will
now generate a *note DeprecationWarning: 1a5, and will trigger a *note
RuntimeError: 195. in Python 3.7.  See *note PEP 479; Change
StopIteration handling inside generators: d47. for details.

The *note __aiter__(): c1c. method is now expected to return an
asynchronous iterator directly instead of returning an awaitable as
previously.  Doing the former will trigger a *note DeprecationWarning:
1a5.  Backward compatibility will be removed in Python 3.7.
(Contributed by Yury Selivanov in bpo-27243(1).)

A backslash-character pair that is not a valid escape sequence now
generates a *note DeprecationWarning: 1a5.  Although this will
eventually become a *note SyntaxError: 18d, that will not be for several
Python releases.  (Contributed by Emanuel Barry in bpo-27364(2).)

When performing a relative import, falling back on ‘__name__’ and
‘__path__’ from the calling module when ‘__spec__’ or ‘__package__’ are
not defined now raises an *note ImportWarning: 4fd.  (Contributed by
Rose Ames in bpo-25791(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27243

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27364

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25791


File: python.info,  Node: Deprecated Python modules functions and methods<2>,  Next: xml<6>,  Prev: Deprecated Python behavior,  Up: Deprecated<9>

1.8.9.3 Deprecated Python modules, functions and methods
........................................................

* Menu:

* asynchat::
* asyncore::
* dbm: dbm<4>.
* distutils: distutils<6>.
* grp::
* importlib: importlib<7>.
* os: os<9>.
* re: re<6>.
* ssl: ssl<8>.
* tkinter: tkinter<7>.
* venv: venv<6>.


File: python.info,  Node: asynchat,  Next: asyncore,  Up: Deprecated Python modules functions and methods<2>

1.8.9.4 asynchat
................

The ‘asynchat’ has been deprecated in favor of *note asyncio: a.
(Contributed by Mariatta in bpo-25002(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25002


File: python.info,  Node: asyncore,  Next: dbm<4>,  Prev: asynchat,  Up: Deprecated Python modules functions and methods<2>

1.8.9.5 asyncore
................

The ‘asyncore’ has been deprecated in favor of *note asyncio: a.
(Contributed by Mariatta in bpo-25002(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25002


File: python.info,  Node: dbm<4>,  Next: distutils<6>,  Prev: asyncore,  Up: Deprecated Python modules functions and methods<2>

1.8.9.6 dbm
...........

Unlike other *note dbm: 31. implementations, the *note dbm.dumb: 32.
module creates databases with the ‘'rw'’ mode and allows modifying the
database opened with the ‘'r'’ mode.  This behavior is now deprecated
and will be removed in 3.8.  (Contributed by Serhiy Storchaka in
bpo-21708(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21708


File: python.info,  Node: distutils<6>,  Next: grp,  Prev: dbm<4>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.7 distutils
.................

The undocumented ‘extra_path’ argument to the ‘distutils.Distribution’
constructor is now considered deprecated and will raise a warning if
set.  Support for this parameter will be removed in a future Python
release.  See bpo-27919(1) for details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27919


File: python.info,  Node: grp,  Next: importlib<7>,  Prev: distutils<6>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.8 grp
...........

The support of non-integer arguments in *note getgrgid(): d4e. has been
deprecated.  (Contributed by Serhiy Storchaka in bpo-26129(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26129


File: python.info,  Node: importlib<7>,  Next: os<9>,  Prev: grp,  Up: Deprecated Python modules functions and methods<2>

1.8.9.9 importlib
.................

The *note importlib.machinery.SourceFileLoader.load_module(): d50. and
*note importlib.machinery.SourcelessFileLoader.load_module(): d51.
methods are now deprecated.  They were the only remaining
implementations of *note importlib.abc.Loader.load_module(): 870. in
*note importlib: 77. that had not been deprecated in previous versions
of Python in favour of *note importlib.abc.Loader.exec_module(): 871.

The *note importlib.machinery.WindowsRegistryFinder: d52. class is now
deprecated.  As of 3.6.0, it is still added to *note sys.meta_path: d53.
by default (on Windows), but this may change in future releases.


File: python.info,  Node: os<9>,  Next: re<6>,  Prev: importlib<7>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.10 os
...........

Undocumented support of general *note bytes-like objects: d55. as paths
in *note os: a1. functions, *note compile(): 192. and similar functions
is now deprecated.  (Contributed by Serhiy Storchaka in bpo-25791(1) and
bpo-26754(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25791

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26754


File: python.info,  Node: re<6>,  Next: ssl<8>,  Prev: os<9>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.11 re
...........

Support for inline flags ‘(?letters)’ in the middle of the regular
expression has been deprecated and will be removed in a future Python
version.  Flags at the start of a regular expression are still allowed.
(Contributed by Serhiy Storchaka in bpo-22493(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22493


File: python.info,  Node: ssl<8>,  Next: tkinter<7>,  Prev: re<6>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.12 ssl
............

OpenSSL 0.9.8, 1.0.0 and 1.0.1 are deprecated and no longer supported.
In the future the *note ssl: d0. module will require at least OpenSSL
1.0.2 or 1.1.0.

SSL-related arguments like ‘certfile’, ‘keyfile’ and ‘check_hostname’ in
*note ftplib: 5e, *note http.client: 6f, *note imaplib: 74, *note
poplib: ac, and *note smtplib: ca. have been deprecated in favor of
‘context’.  (Contributed by Christian Heimes in bpo-28022(1).)

A couple of protocols and functions of the *note ssl: d0. module are now
deprecated.  Some features will no longer be available in future
versions of OpenSSL. Other features are deprecated in favor of a
different API. (Contributed by Christian Heimes in bpo-28022(2) and
bpo-26470(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28022

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28022

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26470


File: python.info,  Node: tkinter<7>,  Next: venv<6>,  Prev: ssl<8>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.13 tkinter
................

The ‘tkinter.tix’ module is now deprecated.  *note tkinter: f0. users
should use *note tkinter.ttk: f9. instead.


File: python.info,  Node: venv<6>,  Prev: tkinter<7>,  Up: Deprecated Python modules functions and methods<2>

1.8.9.14 venv
.............

The ‘pyvenv’ script has been deprecated in favour of ‘python3 -m venv’.
This prevents confusion as to what Python interpreter ‘pyvenv’ is
connected to and thus what Python interpreter will be used by the
virtual environment.  (Contributed by Brett Cannon in bpo-25154(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25154


File: python.info,  Node: xml<6>,  Next: Deprecated functions and types of the C API<2>,  Prev: Deprecated Python modules functions and methods<2>,  Up: Deprecated<9>

1.8.9.15 xml
............

   * As mitigation against DTD and external entity retrieval, the *note
     xml.dom.minidom: 122. and *note xml.sax: 129. modules no longer
     process external entities by default.  (Contributed by Christian
     Heimes in gh-61441(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/61441


File: python.info,  Node: Deprecated functions and types of the C API<2>,  Next: Deprecated Build Options,  Prev: xml<6>,  Up: Deprecated<9>

1.8.9.16 Deprecated functions and types of the C API
....................................................

Undocumented functions ‘PyUnicode_AsEncodedObject()’,
‘PyUnicode_AsDecodedObject()’, ‘PyUnicode_AsEncodedUnicode()’ and
‘PyUnicode_AsDecodedUnicode()’ are deprecated now.  Use the *note
generic codec based API: d5d. instead.


File: python.info,  Node: Deprecated Build Options,  Prev: Deprecated functions and types of the C API<2>,  Up: Deprecated<9>

1.8.9.17 Deprecated Build Options
.................................

The ‘--with-system-ffi’ configure flag is now on by default on non-macOS
UNIX platforms.  It may be disabled by using ‘--without-system-ffi’, but
using the flag is deprecated and will not be accepted in Python 3.7.
macOS is unaffected by this change.  Note that many OS distributors
already use the ‘--with-system-ffi’ flag when building their system
Python.


File: python.info,  Node: Removed<9>,  Next: Porting to Python 3 6,  Prev: Deprecated<9>,  Up: What’s New In Python 3 6

1.8.10 Removed
--------------

* Menu:

* API and Feature Removals: API and Feature Removals<3>.


File: python.info,  Node: API and Feature Removals<3>,  Up: Removed<9>

1.8.10.1 API and Feature Removals
.................................

   * Unknown escapes consisting of ‘'\'’ and an ASCII letter in regular
     expressions will now cause an error.  In replacement templates for
     *note re.sub(): 2a3. they are still allowed, but deprecated.  The
     *note re.LOCALE: b88. flag can now only be used with binary
     patterns.

   * ‘inspect.getmoduleinfo()’ was removed (was deprecated since CPython
     3.3).  *note inspect.getmodulename(): d61. should be used for
     obtaining the module name for a given path.  (Contributed by Yury
     Selivanov in bpo-13248(1).)

   * ‘traceback.Ignore’ class and ‘traceback.usage’,
     ‘traceback.modname’, ‘traceback.fullmodname’,
     ‘traceback.find_lines_from_code’, ‘traceback.find_lines’,
     ‘traceback.find_strings’, ‘traceback.find_executable_lines’ methods
     were removed from the *note traceback: fe. module.  They were
     undocumented methods deprecated since Python 3.2 and equivalent
     functionality is available from private methods.

   * The ‘tk_menuBar()’ and ‘tk_bindForTraversal()’ dummy methods in
     *note tkinter: f0. widget classes were removed (corresponding Tk
     commands were obsolete since Tk 4.0).

   * The *note open(): 41e. method of the *note zipfile.ZipFile: 6c7.
     class no longer supports the ‘'U'’ mode (was deprecated since
     Python 3.4).  Use *note io.TextIOWrapper: 7bf. for reading
     compressed text files in *note universal newlines: d62. mode.

   * The undocumented ‘IN’, ‘CDROM’, ‘DLFCN’, ‘TYPES’, ‘CDIO’, and
     ‘STROPTS’ modules have been removed.  They had been available in
     the platform specific ‘Lib/plat-*/’ directories, but were
     chronically out of date, inconsistently available across platforms,
     and unmaintained.  The script that created these modules is still
     available in the source distribution at Tools/scripts/h2py.py(2).

   * The deprecated ‘asynchat.fifo’ class has been removed.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13248

   (2) 
https://github.com/python/cpython/blob/v3.6.15/Tools/scripts/h2py.py


File: python.info,  Node: Porting to Python 3 6,  Next: Notable changes in Python 3 6 2,  Prev: Removed<9>,  Up: What’s New In Python 3 6

1.8.11 Porting to Python 3.6
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in ‘python’ Command Behavior::
* Changes in the Python API: Changes in the Python API<8>.
* Changes in the C API: Changes in the C API<6>.
* CPython bytecode changes: CPython bytecode changes<7>.


File: python.info,  Node: Changes in ‘python’ Command Behavior,  Next: Changes in the Python API<8>,  Up: Porting to Python 3 6

1.8.11.1 Changes in ‘python’ Command Behavior
.............................................

   * The output of a special Python build with defined ‘COUNT_ALLOCS’,
     ‘SHOW_ALLOC_COUNT’ or ‘SHOW_TRACK_COUNT’ macros is now off by
     default.  It can be re-enabled using the ‘-X showalloccount’
     option.  It now outputs to ‘stderr’ instead of ‘stdout’.
     (Contributed by Serhiy Storchaka in bpo-23034(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23034


File: python.info,  Node: Changes in the Python API<8>,  Next: Changes in the C API<6>,  Prev: Changes in ‘python’ Command Behavior,  Up: Porting to Python 3 6

1.8.11.2 Changes in the Python API
..................................

   * *note open(): 51f. will no longer allow combining the ‘'U'’ mode
     flag with ‘'+'’.  (Contributed by Jeff Balogh and John O’Connor in
     bpo-2091(1).)

   * *note sqlite3: cf. no longer implicitly commits an open transaction
     before DDL statements.

   * On Linux, *note os.urandom(): 526. now blocks until the system
     urandom entropy pool is initialized to increase the security.

   * When *note importlib.abc.Loader.exec_module(): 871. is defined,
     *note importlib.abc.Loader.create_module(): cd4. must also be
     defined.

   * *note PyErr_SetImportError(): d66. now sets *note TypeError: 2c3.
     when its 'msg' argument is not set.  Previously only ‘NULL’ was
     returned.

   * The format of the *note co_lnotab: 2e0. attribute of code objects
     changed to support a negative line number delta.  By default,
     Python does not emit bytecode with a negative line number delta.
     Functions using *note frame.f_lineno: 7b0,
     ‘PyFrame_GetLineNumber()’ or ‘PyCode_Addr2Line()’ are not affected.
     Functions directly decoding ‘co_lnotab’ should be updated to use a
     signed 8-bit integer type for the line number delta, but this is
     only required to support applications using a negative line number
     delta.  See ‘Objects/lnotab_notes.txt’ for the ‘co_lnotab’ format
     and how to decode it, and see the PEP 511(2) for the rationale.

   * The functions in the *note compileall: 20. module now return
     booleans instead of ‘1’ or ‘0’ to represent success or failure,
     respectively.  Thanks to booleans being a subclass of integers,
     this should only be an issue if you were doing identity checks for
     ‘1’ or ‘0’.  See bpo-25768(3).

   * Reading the ‘port’ attribute of *note urllib.parse.urlsplit(): d67.
     and *note urlparse(): 30d. results now raises *note ValueError:
     202. for out-of-range values, rather than returning *note None:
     678.  See bpo-20059(4).

   * The ‘imp’ module now raises a *note DeprecationWarning: 1a5.
     instead of *note PendingDeprecationWarning: 8d1.

   * The following modules have had missing APIs added to their *note
     __all__: d68. attributes to match the documented APIs: *note
     calendar: 14, ‘cgi’, *note csv: 29, *note ElementTree: 125, *note
     enum: 56, *note fileinput: 5b, *note ftplib: 5e, *note logging: 87,
     *note mailbox: 8b, *note mimetypes: 8f, *note optparse: a0, *note
     plistlib: ab, ‘smtpd’, *note subprocess: d6, *note tarfile: de,
     *note threading: ed. and *note wave: 113.  This means they will
     export new symbols when ‘import *’ is used.  (Contributed by Joel
     Taddei and Jacek Kołodziej in bpo-23883(5).)

   * When performing a relative import, if ‘__package__’ does not
     compare equal to ‘__spec__.parent’ then *note ImportWarning: 4fd.
     is raised.  (Contributed by Brett Cannon in bpo-25791(6).)

   * When a relative import is performed and no parent package is known,
     then *note ImportError: 41c. will be raised.  Previously, *note
     SystemError: 578. could be raised.  (Contributed by Brett Cannon in
     bpo-18018(7).)

   * Servers based on the *note socketserver: cd. module, including
     those defined in *note http.server: 72, *note xmlrpc.server: 12f.
     and *note wsgiref.simple_server: 11b, now only catch exceptions
     derived from *note Exception: 9e5.  Therefore if a request handler
     raises an exception like *note SystemExit: d69. or *note
     KeyboardInterrupt: 9dc, *note handle_error(): d6a. is no longer
     called, and the exception will stop a single-threaded server.
     (Contributed by Martin Panter in bpo-23430(8).)

   * ‘spwd.getspnam()’ now raises a *note PermissionError: d6b. instead
     of *note KeyError: 345. if the user doesn’t have privileges.

   * The *note socket.socket.close(): d6c. method now raises an
     exception if an error (e.g.  ‘EBADF’) was reported by the
     underlying system call.  (Contributed by Martin Panter in
     bpo-26685(9).)

   * The 'decode_data' argument for the ‘smtpd.SMTPChannel’ and
     ‘smtpd.SMTPServer’ constructors is now ‘False’ by default.  This
     means that the argument passed to ‘process_message()’ is now a
     bytes object by default, and ‘process_message()’ will be passed
     keyword arguments.  Code that has already been updated in
     accordance with the deprecation warning generated by 3.5 will not
     be affected.

   * All optional arguments of the *note dump(): d6d, *note dumps():
     d6e, *note load(): cda. and *note loads(): 95f. functions and *note
     JSONEncoder: d6f. and *note JSONDecoder: d70. class constructors in
     the *note json: 82. module are now *note keyword-only: 2a5.
     (Contributed by Serhiy Storchaka in bpo-18726(10).)

   * Subclasses of *note type: d71. which don’t override ‘type.__new__’
     may no longer use the one-argument form to get the type of an
     object.

   * As part of PEP 487(11), the handling of keyword arguments passed to
     *note type: d71. (other than the metaclass hint, ‘metaclass’) is
     now consistently delegated to *note object.__init_subclass__():
     634.  This means that *note type.__new__: 583. and *note
     type.__init__: 6b3. both now accept arbitrary keyword arguments,
     but ‘object.__init_subclass__()’ (which is called from
     ‘type.__new__’) will reject them by default.  Custom metaclasses
     accepting additional keyword arguments will need to adjust their
     calls to ‘type.__new__’ (whether direct or via *note super: 4de.)
     accordingly.

   * In ‘distutils.command.sdist.sdist’, the ‘default_format’ attribute
     has been removed and is no longer honored.  Instead, the gzipped
     tarfile format is the default on all platforms and no
     platform-specific selection is made.  In environments where
     distributions are built on Windows and zip distributions are
     required, configure the project with a ‘setup.cfg’ file containing
     the following:

          [sdist]
          formats=zip

     This behavior has also been backported to earlier Python versions
     by Setuptools 26.0.0.

   * In the *note urllib.request: 10b. module and the *note
     http.client.HTTPConnection.request(): ccf. method, if no
     Content-Length header field has been specified and the request body
     is a file object, it is now sent with HTTP 1.1 chunked encoding.
     If a file object has to be sent to a HTTP 1.0 server, the
     Content-Length value now has to be specified by the caller.
     (Contributed by Demian Brecht and Rolf Krahl with tweaks from
     Martin Panter in bpo-12319(12).)

   * The *note DictReader: 9f0. now returns rows of type *note
     OrderedDict: 5de.  (Contributed by Steve Holden in bpo-27842(13).)

   * The ‘crypt.METHOD_CRYPT’ will no longer be added to ‘crypt.methods’
     if unsupported by the platform.  (Contributed by Victor Stinner in
     bpo-25287(14).)

   * The 'verbose' and 'rename' arguments for *note namedtuple(): 1ca.
     are now keyword-only.  (Contributed by Raymond Hettinger in
     bpo-25628(15).)

   * On Linux, *note ctypes.util.find_library(): d72. now looks in
     ‘LD_LIBRARY_PATH’ for shared libraries.  (Contributed by Vinay
     Sajip in bpo-9998(16).)

   * The *note imaplib.IMAP4: 90c. class now handles flags containing
     the ‘']'’ character in messages sent from the server to improve
     real-world compatibility.  (Contributed by Lita Cho in
     bpo-21815(17).)

   * The *note mmap.mmap.write(): d73. function now returns the number
     of bytes written like other write methods.  (Contributed by Jakub
     Stasiak in bpo-26335(18).)

   * The *note pkgutil.iter_modules(): d74. and *note
     pkgutil.walk_packages(): c1f. functions now return *note
     ModuleInfo: d75. named tuples.  (Contributed by Ramchandra Apte in
     bpo-17211(19).)

   * *note re.sub(): 2a3. now raises an error for invalid numerical
     group references in replacement templates even if the pattern is
     not found in the string.  The error message for invalid group
     references now includes the group index and the position of the
     reference.  (Contributed by SilentGhost, Serhiy Storchaka in
     bpo-25953(20).)

   * *note zipfile.ZipFile: 6c7. will now raise *note
     NotImplementedError: 228. for unrecognized compression values.
     Previously a plain *note RuntimeError: 195. was raised.
     Additionally, calling ‘ZipFile’ methods on a closed ZipFile or
     calling the *note write(): d76. method on a ZipFile created with
     mode ‘'r'’ will raise a *note ValueError: 202.  Previously, a
     ‘RuntimeError’ was raised in those scenarios.

   * when custom metaclasses are combined with zero-argument *note
     super(): 4de. or direct references from methods to the implicit
     ‘__class__’ closure variable, the implicit ‘__classcell__’
     namespace entry must now be passed up to ‘type.__new__’ for
     initialisation.  Failing to do so will result in a *note
     DeprecationWarning: 1a5. in Python 3.6 and a *note RuntimeError:
     195. in Python 3.8.

   * With the introduction of *note ModuleNotFoundError: b61, import
     system consumers may start expecting import system replacements to
     raise that more specific exception when appropriate, rather than
     the less-specific *note ImportError: 41c.  To provide future
     compatibility with such consumers, implementers of alternative
     import systems that completely replace *note __import__(): 8dd.
     will need to update their implementations to raise the new subclass
     when a module can’t be found at all.  Implementers of compliant
     plugins to the default import system shouldn’t need to make any
     changes, as the default import system will raise the new subclass
     when appropriate.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2091

   (2) https://peps.python.org/pep-0511/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25768

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20059

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23883

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25791

   (7) https://bugs.python.org/issue?@action=redirect&bpo=18018

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23430

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26685

   (10) https://bugs.python.org/issue?@action=redirect&bpo=18726

   (11) https://peps.python.org/pep-0487/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=12319

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27842

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25287

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25628

   (16) https://bugs.python.org/issue?@action=redirect&bpo=9998

   (17) https://bugs.python.org/issue?@action=redirect&bpo=21815

   (18) https://bugs.python.org/issue?@action=redirect&bpo=26335

   (19) https://bugs.python.org/issue?@action=redirect&bpo=17211

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25953


File: python.info,  Node: Changes in the C API<6>,  Next: CPython bytecode changes<7>,  Prev: Changes in the Python API<8>,  Up: Porting to Python 3 6

1.8.11.3 Changes in the C API
.............................

   * The *note PyMem_Malloc(): c87. allocator family now uses the *note
     pymalloc allocator: d37. rather than the system ‘malloc()’.
     Applications calling ‘PyMem_Malloc()’ without holding the GIL can
     now crash.  Set the *note PYTHONMALLOC: c85. environment variable
     to ‘debug’ to validate the usage of memory allocators in your
     application.  See bpo-26249(1).

   * *note Py_Exit(): d78. (and the main interpreter) now override the
     exit status with 120 if flushing buffered data failed.  See
     bpo-5319(2).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26249

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5319


File: python.info,  Node: CPython bytecode changes<7>,  Prev: Changes in the C API<6>,  Up: Porting to Python 3 6

1.8.11.4 CPython bytecode changes
.................................

There have been several major changes to the *note bytecode: 187. in
Python 3.6.

   * The Python interpreter now uses a 16-bit wordcode instead of
     bytecode.  (Contributed by Demur Rumed with input and reviews from
     Serhiy Storchaka and Victor Stinner in bpo-26647(1) and
     bpo-28050(2).)

   * The new ‘FORMAT_VALUE’ and *note BUILD_STRING: d7a. opcodes as part
     of the *note formatted string literal: c50. implementation.
     (Contributed by Eric Smith in bpo-25483(3) and Serhiy Storchaka in
     bpo-27078(4).)

   * The new *note BUILD_CONST_KEY_MAP: d7b. opcode to optimize the
     creation of dictionaries with constant keys.  (Contributed by
     Serhiy Storchaka in bpo-27140(5).)

   * The function call opcodes have been heavily reworked for better
     performance and simpler implementation.  The *note MAKE_FUNCTION:
     d7c, ‘CALL_FUNCTION’, ‘CALL_FUNCTION_KW’ and
     ‘BUILD_MAP_UNPACK_WITH_CALL’ opcodes have been modified, the new
     *note CALL_FUNCTION_EX: d7d. and ‘BUILD_TUPLE_UNPACK_WITH_CALL’
     have been added, and ‘CALL_FUNCTION_VAR’, ‘CALL_FUNCTION_VAR_KW’
     and ‘MAKE_CLOSURE’ opcodes have been removed.  (Contributed by
     Demur Rumed in bpo-27095(6), and Serhiy Storchaka in bpo-27213(7),
     bpo-28257(8).)

   * The new *note SETUP_ANNOTATIONS: d7e. and ‘STORE_ANNOTATION’
     opcodes have been added to support the new *note variable
     annotation: d7f. syntax.  (Contributed by Ivan Levkivskyi in
     bpo-27985(9).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26647

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28050

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25483

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27078

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27140

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27095

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27213

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28257

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27985


File: python.info,  Node: Notable changes in Python 3 6 2,  Next: Notable changes in Python 3 6 4,  Prev: Porting to Python 3 6,  Up: What’s New In Python 3 6

1.8.12 Notable changes in Python 3.6.2
--------------------------------------

* Menu:

* New make regen-all build target::
* Removal of make touch build target::


File: python.info,  Node: New make regen-all build target,  Next: Removal of make touch build target,  Up: Notable changes in Python 3 6 2

1.8.12.1 New ‘make regen-all’ build target
..........................................

To simplify cross-compilation, and to ensure that CPython can reliably
be compiled without requiring an existing version of Python to already
be available, the autotools-based build system no longer attempts to
implicitly recompile generated files based on file modification times.

Instead, a new ‘make regen-all’ command has been added to force
regeneration of these files when desired (e.g.  after an initial version
of Python has already been built based on the pregenerated versions).

More selective regeneration targets are also defined - see
Makefile.pre.in(1) for details.

(Contributed by Victor Stinner in bpo-23404(2).)

Added in version 3.6.2.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Makefile.pre.in

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: Removal of make touch build target,  Prev: New make regen-all build target,  Up: Notable changes in Python 3 6 2

1.8.12.2 Removal of ‘make touch’ build target
.............................................

The ‘make touch’ build target previously used to request implicit
regeneration of generated files by updating their modification times has
been removed.

It has been replaced by the new ‘make regen-all’ target.

(Contributed by Victor Stinner in bpo-23404(1).)

Changed in version 3.6.2.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: Notable changes in Python 3 6 4,  Next: Notable changes in Python 3 6 5,  Prev: Notable changes in Python 3 6 2,  Up: What’s New In Python 3 6

1.8.13 Notable changes in Python 3.6.4
--------------------------------------

The ‘PyExc_RecursionErrorInst’ singleton that was part of the public API
has been removed as its members being never cleared may cause a segfault
during finalization of the interpreter.  (Contributed by Xavier de Gaye
in bpo-22898(1) and bpo-30697(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22898

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30697


File: python.info,  Node: Notable changes in Python 3 6 5,  Next: Notable changes in Python 3 6 7,  Prev: Notable changes in Python 3 6 4,  Up: What’s New In Python 3 6

1.8.14 Notable changes in Python 3.6.5
--------------------------------------

The *note locale.localeconv(): c1e. function now sets temporarily the
‘LC_CTYPE’ locale to the ‘LC_NUMERIC’ locale in some cases.
(Contributed by Victor Stinner in bpo-31900(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31900


File: python.info,  Node: Notable changes in Python 3 6 7,  Next: Notable changes in Python 3 6 10,  Prev: Notable changes in Python 3 6 5,  Up: What’s New In Python 3 6

1.8.15 Notable changes in Python 3.6.7
--------------------------------------

*note xml.dom.minidom: 122. and *note xml.sax: 129. modules no longer
process external entities by default.  See also gh-61441(1).

In 3.6.7 the *note tokenize: fb. module now implicitly emits a ‘NEWLINE’
token when provided with input that does not have a trailing new line.
This behavior now matches what the C tokenizer does internally.
(Contributed by Ammar Askar in bpo-33899(2).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/61441

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33899


File: python.info,  Node: Notable changes in Python 3 6 10,  Next: Notable changes in Python 3 6 13,  Prev: Notable changes in Python 3 6 7,  Up: What’s New In Python 3 6

1.8.16 Notable changes in Python 3.6.10
---------------------------------------

Due to significant security concerns, the 'reuse_address' parameter of
*note asyncio.loop.create_datagram_endpoint(): 736. is no longer
supported.  This is because of the behavior of the socket option
‘SO_REUSEADDR’ in UDP. For more details, see the documentation for
‘loop.create_datagram_endpoint()’.  (Contributed by Kyle Stanley,
Antoine Pitrou, and Yury Selivanov in bpo-37228(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37228


File: python.info,  Node: Notable changes in Python 3 6 13,  Next: Notable changes in Python 3 6 14,  Prev: Notable changes in Python 3 6 10,  Up: What’s New In Python 3 6

1.8.17 Notable changes in Python 3.6.13
---------------------------------------

Earlier Python versions allowed using both ‘;’ and ‘&’ as query
parameter separators in *note urllib.parse.parse_qs(): 27a. and *note
urllib.parse.parse_qsl(): 279.  Due to security concerns, and to conform
with newer W3C recommendations, this has been changed to allow only a
single separator key, with ‘&’ as the default.  This change also affects
‘cgi.parse()’ and ‘cgi.parse_multipart()’ as they use the affected
functions internally.  For more details, please see their respective
documentation.  (Contributed by Adam Goldschmidt, Senthil Kumaran and
Ken Jin in bpo-42967(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967


File: python.info,  Node: Notable changes in Python 3 6 14,  Prev: Notable changes in Python 3 6 13,  Up: What’s New In Python 3 6

1.8.18 Notable changes in Python 3.6.14
---------------------------------------

A security fix alters the *note ftplib.FTP: 903. behavior to not trust
the IPv4 address sent from the remote server when setting up a passive
data channel.  We reuse the ftp server IP address instead.  For unusual
code requiring the old behavior, set a ‘trust_server_pasv_ipv4_address’
attribute on your FTP instance to ‘True’.  (See gh-87451(1))

The presence of newline or tab characters in parts of a URL allows for
some forms of attacks.  Following the WHATWG specification that updates
RFC 3986, ASCII newline ‘\n’, ‘\r’ and tab ‘\t’ characters are stripped
from the URL by the parser *note urllib.parse(): 10a. preventing such
attacks.  The removal characters are controlled by a new module level
variable ‘urllib.parse._UNSAFE_URL_BYTES_TO_REMOVE’.  (See gh-88048(2))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87451

   (2) https://github.com/python/cpython/issues/88048


File: python.info,  Node: What’s New In Python 3 5,  Next: What’s New In Python 3 4,  Prev: What’s New In Python 3 6,  Up: What’s New in Python

1.9 What’s New In Python 3.5
============================


Editors: Elvis Pranskevichus <<elvis@magic.io>>, Yury Selivanov
<<yury@magic.io>>

This article explains the new features in Python 3.5, compared to 3.4.
Python 3.5 was released on September 13, 2015.   See the changelog(1)
for a full list of changes.

See also
........

PEP 478(2) - Python 3.5 Release Schedule

* Menu:

* Summary – Release highlights: Summary – Release highlights<7>.
* New Features: New Features<14>.
* Other Language Changes: Other Language Changes<9>.
* New Modules: New Modules<9>.
* Improved Modules: Improved Modules<9>.
* Other module-level changes::
* Optimizations: Optimizations<9>.
* Build and C API Changes: Build and C API Changes<3>.
* Deprecated: Deprecated<10>.
* Removed: Removed<10>.
* Porting to Python 3.5: Porting to Python 3 5.
* Notable changes in Python 3.5.4: Notable changes in Python 3 5 4.

   ---------- Footnotes ----------

   (1) https://docs.python.org/3.5/whatsnew/changelog.html

   (2) https://peps.python.org/pep-0478/


File: python.info,  Node: Summary – Release highlights<7>,  Next: New Features<14>,  Up: What’s New In Python 3 5

1.9.1 Summary – Release highlights
----------------------------------

New syntax features:

   * *note PEP 492: d8d, coroutines with async and await syntax.

   * *note PEP 465: d8e, a new matrix multiplication operator: ‘a @ b’.

   * *note PEP 448: d8f, additional unpacking generalizations.

New library modules:

   * *note typing: 104.: *note PEP 484 – Type Hints: d90.

   * *note zipapp: 130.: *note PEP 441 Improving Python ZIP Application
     Support: d91.

New built-in features:

   * ‘bytes % args’, ‘bytearray % args’: *note PEP 461: d92. – Adding
     ‘%’ formatting to bytes and bytearray.

   * New *note bytes.hex(): d93, *note bytearray.hex(): d94. and *note
     memoryview.hex(): d95. methods.  (Contributed by Arnon Yaari in
     bpo-9951(1).)

   * *note memoryview: 2eb. now supports tuple indexing (including
     multi-dimensional).  (Contributed by Antoine Pitrou in
     bpo-23632(2).)

   * Generators have a new ‘gi_yieldfrom’ attribute, which returns the
     object being iterated by ‘yield from’ expressions.  (Contributed by
     Benno Leslie and Yury Selivanov in bpo-24450(3).)

   * A new *note RecursionError: d96. exception is now raised when
     maximum recursion depth is reached.  (Contributed by Georg Brandl
     in bpo-19235(4).)

CPython implementation improvements:

   * When the ‘LC_TYPE’ locale is the POSIX locale (‘C’ locale), *note
     sys.stdin: 540. and *note sys.stdout: aec. now use the
     ‘surrogateescape’ error handler, instead of the ‘strict’ error
     handler.  (Contributed by Victor Stinner in bpo-19977(5).)

   * ‘.pyo’ files are no longer used and have been replaced by a more
     flexible scheme that includes the optimization level explicitly in
     ‘.pyc’ name.  (See *note PEP 488 overview: d97.)

   * Builtin and extension modules are now initialized in a multi-phase
     process, which is similar to how Python modules are loaded.  (See
     *note PEP 489 overview: d98.)

Significant improvements in the standard library:

   * *note collections.OrderedDict: 5de. is now *note implemented in C:
     d99, which makes it 4 to 100 times faster.

   * The *note ssl: d0. module gained *note support for Memory BIO: d9a,
     which decouples SSL protocol handling from network IO.

   * The new *note os.scandir(): a6d. function provides a *note better
     and significantly faster way: d9b. of directory traversal.

   * *note functools.lru_cache(): 9fa. has been mostly *note
     reimplemented in C: d9c, yielding much better performance.

   * The new *note subprocess.run(): ba4. function provides a *note
     streamlined way to run subprocesses: d9d.

   * The *note traceback: fe. module has been significantly *note
     enhanced: d9e. for improved performance and developer convenience.

Security improvements:

   * SSLv3 is now disabled throughout the standard library.  It can
     still be enabled by instantiating a *note ssl.SSLContext: 294.
     manually.  (See bpo-22638(6) for more details; this change was
     backported to CPython 3.4 and 2.7.)

   * HTTP cookie parsing is now stricter, in order to protect against
     potential injection attacks.  (Contributed by Antoine Pitrou in
     bpo-22796(7).)

Windows improvements:

   * A new installer for Windows has replaced the old MSI. See *note
     Using Python on Windows: abc. for more information.

   * Windows builds now use Microsoft Visual C++ 14.0, and extension
     modules should use the same.

Please read on for a comprehensive list of user-facing changes,
including many other smaller improvements, CPython optimizations,
deprecations, and potential porting issues.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9951

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23632

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24450

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19235

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19977

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22638

   (7) https://bugs.python.org/issue?@action=redirect&bpo=22796


File: python.info,  Node: New Features<14>,  Next: Other Language Changes<9>,  Prev: Summary – Release highlights<7>,  Up: What’s New In Python 3 5

1.9.2 New Features
------------------

* Menu:

* PEP 492 - Coroutines with async and await syntax::
* PEP 465 - A dedicated infix operator for matrix multiplication::
* PEP 448 - Additional Unpacking Generalizations::
* PEP 461 - percent formatting support for bytes and bytearray::
* PEP 484 - Type Hints::
* PEP 471 - os.scandir() function – a better and faster directory iterator: PEP 471 - os scandir function – a better and faster directory iterator.
* PEP 475; Retry system calls failing with EINTR: PEP 475 Retry system calls failing with EINTR.
* PEP 479; Change StopIteration handling inside generators: PEP 479 Change StopIteration handling inside generators.
* PEP 485; A function for testing approximate equality: PEP 485 A function for testing approximate equality.
* PEP 486; Make the Python Launcher aware of virtual environments: PEP 486 Make the Python Launcher aware of virtual environments.
* PEP 488; Elimination of PYO files: PEP 488 Elimination of PYO files.
* PEP 489; Multi-phase extension module initialization: PEP 489 Multi-phase extension module initialization.


File: python.info,  Node: PEP 492 - Coroutines with async and await syntax,  Next: PEP 465 - A dedicated infix operator for matrix multiplication,  Up: New Features<14>

1.9.2.1 PEP 492 - Coroutines with async and await syntax
........................................................

PEP 492(1) greatly improves support for asynchronous programming in
Python by adding *note awaitable objects: 1ad, *note coroutine
functions: da1, *note asynchronous iteration: da2, and *note
asynchronous context managers: 5da.

Coroutine functions are declared using the new *note async def: 5d4.
syntax:

     >>> async def coro():
     ...     return 'spam'

Inside a coroutine function, the new *note await: 1b9. expression can be
used to suspend coroutine execution until the result is available.  Any
object can be 'awaited', as long as it implements the *note awaitable:
1ad. protocol by defining the *note __await__(): da3. method.

PEP 492 also adds *note async for: ac0. statement for convenient
iteration over asynchronous iterables.

An example of a rudimentary HTTP client written using the new syntax:

     import asyncio

     async def http_get(domain):
         reader, writer = await asyncio.open_connection(domain, 80)

         writer.write(b'\r\n'.join([
             b'GET / HTTP/1.1',
             b'Host: %b' % domain.encode('latin-1'),
             b'Connection: close',
             b'', b''
         ]))

         async for line in reader:
             print('>>>', line)

         writer.close()

     loop = asyncio.get_event_loop()
     try:
         loop.run_until_complete(http_get('example.com'))
     finally:
         loop.close()

Similarly to asynchronous iteration, there is a new syntax for
asynchronous context managers.  The following script:

     import asyncio

     async def coro(name, lock):
         print('coro {}: waiting for lock'.format(name))
         async with lock:
             print('coro {}: holding the lock'.format(name))
             await asyncio.sleep(1)
             print('coro {}: releasing the lock'.format(name))

     loop = asyncio.get_event_loop()
     lock = asyncio.Lock()
     coros = asyncio.gather(coro(1, lock), coro(2, lock))
     try:
         loop.run_until_complete(coros)
     finally:
         loop.close()

will output:

     coro 2: waiting for lock
     coro 2: holding the lock
     coro 1: waiting for lock
     coro 2: releasing the lock
     coro 1: holding the lock
     coro 1: releasing the lock

Note that both *note async for: ac0. and *note async with: 5d8. can only
be used inside a coroutine function declared with *note async def: 5d4.

Coroutine functions are intended to be run inside a compatible event
loop, such as the *note asyncio loop: da4.

     Note: 
     Changed in version 3.5.2: Starting with CPython 3.5.2, ‘__aiter__’
     can directly return *note asynchronous iterators: 1ab.  Returning
     an *note awaitable: 1ad. object will result in a *note
     PendingDeprecationWarning: 8d1.

     See more details in the *note Asynchronous Iterators: da5.
     documentation section.

See also
........

PEP 492(2) – Coroutines with async and await syntax

     PEP written and implemented by Yury Selivanov.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/

   (2) https://peps.python.org/pep-0492/


File: python.info,  Node: PEP 465 - A dedicated infix operator for matrix multiplication,  Next: PEP 448 - Additional Unpacking Generalizations,  Prev: PEP 492 - Coroutines with async and await syntax,  Up: New Features<14>

1.9.2.2 PEP 465 - A dedicated infix operator for matrix multiplication
......................................................................

PEP 465(1) adds the ‘@’ infix operator for matrix multiplication.
Currently, no builtin Python types implement the new operator, however,
it can be implemented by defining *note __matmul__(): da7, *note
__rmatmul__(): da8, and *note __imatmul__(): da9. for regular,
reflected, and in-place matrix multiplication.  The semantics of these
methods is similar to that of methods defining other infix arithmetic
operators.

Matrix multiplication is a notably common operation in many fields of
mathematics, science, engineering, and the addition of ‘@’ allows
writing cleaner code:

     S = (H @ beta - r).T @ inv(H @ V @ H.T) @ (H @ beta - r)

instead of:

     S = dot((dot(H, beta) - r).T,
             dot(inv(dot(dot(H, V), H.T)), dot(H, beta) - r))

NumPy 1.10 has support for the new operator:

     >>> import numpy

     >>> x = numpy.ones(3)
     >>> x
     array([ 1., 1., 1.])

     >>> m = numpy.eye(3)
     >>> m
     array([[ 1., 0., 0.],
            [ 0., 1., 0.],
            [ 0., 0., 1.]])

     >>> x @ m
     array([ 1., 1., 1.])

See also
........

PEP 465(2) – A dedicated infix operator for matrix multiplication

     PEP written by Nathaniel J. Smith; implemented by Benjamin
     Peterson.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0465/

   (2) https://peps.python.org/pep-0465/


File: python.info,  Node: PEP 448 - Additional Unpacking Generalizations,  Next: PEP 461 - percent formatting support for bytes and bytearray,  Prev: PEP 465 - A dedicated infix operator for matrix multiplication,  Up: New Features<14>

1.9.2.3 PEP 448 - Additional Unpacking Generalizations
......................................................

PEP 448(1) extends the allowed uses of the ‘*’ iterable unpacking
operator and ‘**’ dictionary unpacking operator.  It is now possible to
use an arbitrary number of unpackings in *note function calls: dab.:

     >>> print(*[1], *[2], 3, *[4, 5])
     1 2 3 4 5

     >>> def fn(a, b, c, d):
     ...     print(a, b, c, d)
     ...

     >>> fn(**{'a': 1, 'c': 3}, **{'b': 2, 'd': 4})
     1 2 3 4

Similarly, tuple, list, set, and dictionary displays allow multiple
unpackings (see *note Expression lists: dac. and *note Dictionary
displays: dad.):

     >>> *range(4), 4
     (0, 1, 2, 3, 4)

     >>> [*range(4), 4]
     [0, 1, 2, 3, 4]

     >>> {*range(4), 4, *(5, 6, 7)}
     {0, 1, 2, 3, 4, 5, 6, 7}

     >>> {'x': 1, **{'y': 2}}
     {'x': 1, 'y': 2}

See also
........

PEP 448(2) – Additional Unpacking Generalizations

     PEP written by Joshua Landau; implemented by Neil Girdhar, Thomas
     Wouters, and Joshua Landau.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0448/

   (2) https://peps.python.org/pep-0448/


File: python.info,  Node: PEP 461 - percent formatting support for bytes and bytearray,  Next: PEP 484 - Type Hints,  Prev: PEP 448 - Additional Unpacking Generalizations,  Up: New Features<14>

1.9.2.4 PEP 461 - percent formatting support for bytes and bytearray
....................................................................

PEP 461(1) adds support for the ‘%’ *note interpolation operator: daf.
to *note bytes: 1c2. and *note bytearray: 2ea.

While interpolation is usually thought of as a string operation, there
are cases where interpolation on ‘bytes’ or ‘bytearrays’ makes sense,
and the work needed to make up for this missing functionality detracts
from the overall readability of the code.  This issue is particularly
important when dealing with wire format protocols, which are often a
mixture of binary and ASCII compatible text.

Examples:

     >>> b'Hello %b!' % b'World'
     b'Hello World!'

     >>> b'x=%i y=%f' % (1, 2.5)
     b'x=1 y=2.500000'

Unicode is not allowed for ‘%b’, but it is accepted by ‘%a’ (equivalent
of ‘repr(obj).encode('ascii', 'backslashreplace')’):

     >>> b'Hello %b!' % 'World'
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: %b requires bytes, or an object that implements __bytes__, not 'str'

     >>> b'price: %a' % '10€'
     b"price: '10\\u20ac'"

Note that ‘%s’ and ‘%r’ conversion types, although supported, should
only be used in codebases that need compatibility with Python 2.

See also
........

PEP 461(2) – Adding % formatting to bytes and bytearray

     PEP written by Ethan Furman; implemented by Neil Schemenauer and
     Ethan Furman.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0461/

   (2) https://peps.python.org/pep-0461/


File: python.info,  Node: PEP 484 - Type Hints,  Next: PEP 471 - os scandir function – a better and faster directory iterator,  Prev: PEP 461 - percent formatting support for bytes and bytearray,  Up: New Features<14>

1.9.2.5 PEP 484 - Type Hints
............................

Function annotation syntax has been a Python feature since version 3.0 (
PEP 3107(1)), however the semantics of annotations has been left
undefined.

Experience has shown that the majority of function annotation uses were
to provide type hints to function parameters and return values.  It
became evident that it would be beneficial for Python users, if the
standard library included the base definitions and tools for type
annotations.

PEP 484(2) introduces a *note provisional module: b1c. to provide these
standard definitions and tools, along with some conventions for
situations where annotations are not available.

For example, here is a simple function whose argument and return type
are declared in the annotations:

     def greeting(name: str) -> str:
         return 'Hello ' + name

While these annotations are available at runtime through the usual
‘__annotations__’ attribute, 'no automatic type checking happens at
runtime'.  Instead, it is assumed that a separate off-line type checker
(e.g.  mypy(3)) will be used for on-demand source code analysis.

The type system supports unions, generic types, and a special type named
*note Any: 6af. which is consistent with (i.e.  assignable to and from)
all types.

See also
........

   * *note typing: 104. module documentation

   * 
     PEP 484(4) – Type Hints

          PEP written by Guido van Rossum, Jukka Lehtosalo, and Łukasz
          Langa; implemented by Guido van Rossum.

   * 
     PEP 483(5) – The Theory of Type Hints

          PEP written by Guido van Rossum

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3107/

   (2) https://peps.python.org/pep-0484/

   (3) https://mypy-lang.org

   (4) https://peps.python.org/pep-0484/

   (5) https://peps.python.org/pep-0483/


File: python.info,  Node: PEP 471 - os scandir function – a better and faster directory iterator,  Next: PEP 475 Retry system calls failing with EINTR,  Prev: PEP 484 - Type Hints,  Up: New Features<14>

1.9.2.6 PEP 471 - os.scandir() function – a better and faster directory iterator
................................................................................

PEP 471(1) adds a new directory iteration function, *note os.scandir():
a6d, to the standard library.  Additionally, *note os.walk(): 4ac. is
now implemented using ‘scandir’, which makes it 3 to 5 times faster on
POSIX systems and 7 to 20 times faster on Windows systems.  This is
largely achieved by greatly reducing the number of calls to *note
os.stat(): 4a3. required to walk a directory tree.

Additionally, ‘scandir’ returns an iterator, as opposed to returning a
list of file names, which improves memory efficiency when iterating over
very large directories.

The following example shows a simple use of *note os.scandir(): a6d. to
display all the files (excluding directories) in the given 'path' that
don’t start with ‘'.'’.  The *note entry.is_file(): db2. call will
generally not make an additional system call:

     for entry in os.scandir(path):
         if not entry.name.startswith('.') and entry.is_file():
             print(entry.name)

See also
........

PEP 471(2) – os.scandir() function – a better and faster directory iterator

     PEP written and implemented by Ben Hoyt with the help of Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0471/

   (2) https://peps.python.org/pep-0471/


File: python.info,  Node: PEP 475 Retry system calls failing with EINTR,  Next: PEP 479 Change StopIteration handling inside generators,  Prev: PEP 471 - os scandir function – a better and faster directory iterator,  Up: New Features<14>

1.9.2.7 PEP 475: Retry system calls failing with EINTR
......................................................

An *note errno.EINTR: db5. error code is returned whenever a system
call, that is waiting for I/O, is interrupted by a signal.  Previously,
Python would raise *note InterruptedError: db6. in such cases.  This
meant that, when writing a Python application, the developer had two
choices:

  1. Ignore the ‘InterruptedError’.

  2. Handle the ‘InterruptedError’ and attempt to restart the
     interrupted system call at every call site.

The first option makes an application fail intermittently.  The second
option adds a large amount of boilerplate that makes the code nearly
unreadable.  Compare:

     print("Hello World")

and:

     while True:
         try:
             print("Hello World")
             break
         except InterruptedError:
             continue

PEP 475(1) implements automatic retry of system calls on ‘EINTR’.  This
removes the burden of dealing with ‘EINTR’ or *note InterruptedError:
db6. in user code in most situations and makes Python programs,
including the standard library, more robust.  Note that the system call
is only retried if the signal handler does not raise an exception.

Below is a list of functions which are now retried when interrupted by a
signal:

   * *note open(): 51f. and *note io.open(): 520.;

   * functions of the *note faulthandler: 58. module;

   * *note os: a1. functions: *note fchdir(): db7, *note fchmod(): 21c,
     *note fchown(): db8, *note fdatasync(): db9, *note fstat(): dba,
     *note fstatvfs(): dbb, *note fsync(): dbc, *note ftruncate(): dbd,
     *note mkfifo(): dbe, *note mknod(): dbf, *note open(): dc0, *note
     posix_fadvise(): dc1, *note posix_fallocate(): dc2, *note pread():
     b7b, *note pwrite(): b7e, *note read(): dc3, *note readv(): b7a,
     *note sendfile(): b28, *note wait3(): dc4, *note wait4(): dc5,
     *note wait(): dc6, *note waitid(): dc7, *note waitpid(): dc8, *note
     write(): dc9, *note writev(): b7d.;

   * special cases: *note os.close(): b90. and *note os.dup2(): b7f. now
     ignore *note EINTR: db5. errors; the syscall is not retried (see
     the PEP for the rationale);

   * *note select: c1. functions: *note devpoll.poll(): dca, *note
     epoll.poll(): dcb, *note kqueue.control(): dcc, *note poll.poll():
     dcd, *note select(): dce.;

   * methods of the *note socket: dcf. class: *note accept(): dd0, *note
     connect(): dd1. (except for non-blocking sockets), *note recv():
     dd2, *note recvfrom(): dd3, *note recvmsg(): dd4, *note send():
     dd5, *note sendall(): dd6, *note sendmsg(): 479, *note sendto():
     dd7.;

   * *note signal.sigtimedwait(): dd8. and *note signal.sigwaitinfo():
     dd9.;

   * *note time.sleep(): 6a0.

See also
........

PEP 475(2) – Retry system calls failing with EINTR

     PEP and implementation written by Charles-François Natali and
     Victor Stinner, with the help of Antoine Pitrou (the French
     connection).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://peps.python.org/pep-0475/


File: python.info,  Node: PEP 479 Change StopIteration handling inside generators,  Next: PEP 485 A function for testing approximate equality,  Prev: PEP 475 Retry system calls failing with EINTR,  Up: New Features<14>

1.9.2.8 PEP 479: Change StopIteration handling inside generators
................................................................

The interaction of generators and *note StopIteration: c1b. in Python
3.4 and earlier was sometimes surprising, and could conceal obscure
bugs.  Previously, ‘StopIteration’ raised accidentally inside a
generator function was interpreted as the end of the iteration by the
loop construct driving the generator.

PEP 479(1) changes the behavior of generators: when a ‘StopIteration’
exception is raised inside a generator, it is replaced with a *note
RuntimeError: 195. before it exits the generator frame.  The main goal
of this change is to ease debugging in the situation where an unguarded
*note next(): 7dc. call raises ‘StopIteration’ and causes the iteration
controlled by the generator to terminate silently.  This is particularly
pernicious in combination with the ‘yield from’ construct.

This is a backwards incompatible change, so to enable the new behavior,
a *note __future__: ddb. import is necessary:

     >>> from __future__ import generator_stop

     >>> def gen():
     ...     next(iter([]))
     ...     yield
     ...
     >>> next(gen())
     Traceback (most recent call last):
       File "<stdin>", line 2, in gen
     StopIteration

     The above exception was the direct cause of the following exception:

     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     RuntimeError: generator raised StopIteration

Without a ‘__future__’ import, a *note PendingDeprecationWarning: 8d1.
will be raised whenever a *note StopIteration: c1b. exception is raised
inside a generator.

See also
........

PEP 479(2) – Change StopIteration handling inside generators

     PEP written by Chris Angelico and Guido van Rossum.  Implemented by
     Chris Angelico, Yury Selivanov and Nick Coghlan.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0479/

   (2) https://peps.python.org/pep-0479/


File: python.info,  Node: PEP 485 A function for testing approximate equality,  Next: PEP 486 Make the Python Launcher aware of virtual environments,  Prev: PEP 479 Change StopIteration handling inside generators,  Up: New Features<14>

1.9.2.9 PEP 485: A function for testing approximate equality
............................................................

PEP 485(1) adds the *note math.isclose(): dde. and *note
cmath.isclose(): ddf. functions which tell whether two values are
approximately equal or “close” to each other.  Whether or not two values
are considered close is determined according to given absolute and
relative tolerances.  Relative tolerance is the maximum allowed
difference between ‘isclose’ arguments, relative to the larger absolute
value:

     >>> import math
     >>> a = 5.0
     >>> b = 4.99998
     >>> math.isclose(a, b, rel_tol=1e-5)
     True
     >>> math.isclose(a, b, rel_tol=1e-6)
     False

It is also possible to compare two values using absolute tolerance,
which must be a non-negative value:

     >>> import math
     >>> a = 5.0
     >>> b = 4.99998
     >>> math.isclose(a, b, abs_tol=0.00003)
     True
     >>> math.isclose(a, b, abs_tol=0.00001)
     False

See also
........

PEP 485(2) – A function for testing approximate equality

     PEP written by Christopher Barker; implemented by Chris Barker and
     Tal Einat.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0485/

   (2) https://peps.python.org/pep-0485/


File: python.info,  Node: PEP 486 Make the Python Launcher aware of virtual environments,  Next: PEP 488 Elimination of PYO files,  Prev: PEP 485 A function for testing approximate equality,  Up: New Features<14>

1.9.2.10 PEP 486: Make the Python Launcher aware of virtual environments
........................................................................

PEP 486(1) makes the Windows launcher (see PEP 397(2)) aware of an
active virtual environment.  When the default interpreter would be used
and the ‘VIRTUAL_ENV’ environment variable is set, the interpreter in
the virtual environment will be used.

See also
........

PEP 486(3) – Make the Python Launcher aware of virtual environments

     PEP written and implemented by Paul Moore.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0486/

   (2) https://peps.python.org/pep-0397/

   (3) https://peps.python.org/pep-0486/


File: python.info,  Node: PEP 488 Elimination of PYO files,  Next: PEP 489 Multi-phase extension module initialization,  Prev: PEP 486 Make the Python Launcher aware of virtual environments,  Up: New Features<14>

1.9.2.11 PEP 488: Elimination of PYO files
..........................................

PEP 488(1) does away with the concept of ‘.pyo’ files.  This means that
‘.pyc’ files represent both unoptimized and optimized bytecode.  To
prevent the need to constantly regenerate bytecode files, ‘.pyc’ files
now have an optional ‘opt-’ tag in their name when the bytecode is
optimized.  This has the side-effect of no more bytecode file name
clashes when running under either *note -O: de3. or *note -OO: de4.
Consequently, bytecode files generated from ‘-O’, and ‘-OO’ may now
exist simultaneously.  *note importlib.util.cache_from_source(): 2fe.
has an updated API to help with this change.

See also
........

PEP 488(2) – Elimination of PYO files

     PEP written and implemented by Brett Cannon.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0488/

   (2) https://peps.python.org/pep-0488/


File: python.info,  Node: PEP 489 Multi-phase extension module initialization,  Prev: PEP 488 Elimination of PYO files,  Up: New Features<14>

1.9.2.12 PEP 489: Multi-phase extension module initialization
.............................................................

PEP 489(1) updates extension module initialization to take advantage of
the two step module loading mechanism introduced by PEP 451(2) in Python
3.4.

This change brings the import semantics of extension modules that opt-in
to using the new mechanism much closer to those of Python source and
bytecode modules, including the ability to use any valid identifier as a
module name, rather than being restricted to ASCII.

See also
........

PEP 489(3) – Multi-phase extension module initialization

     PEP written by Petr Viktorin, Stefan Behnel, and Nick Coghlan;
     implemented by Petr Viktorin.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0489/

   (2) https://peps.python.org/pep-0451/

   (3) https://peps.python.org/pep-0489/


File: python.info,  Node: Other Language Changes<9>,  Next: New Modules<9>,  Prev: New Features<14>,  Up: What’s New In Python 3 5

1.9.3 Other Language Changes
----------------------------

Some smaller changes made to the core Python language are:

   * Added the ‘"namereplace"’ error handlers.  The ‘"backslashreplace"’
     error handlers now work with decoding and translating.
     (Contributed by Serhiy Storchaka in bpo-19676(1) and bpo-22286(2).)

   * The *note -b: 5e6. option now affects comparisons of *note bytes:
     1c2. with *note int: 257.  (Contributed by Serhiy Storchaka in
     bpo-23681(3).)

   * New Kazakh ‘kz1048’ and Tajik ‘koi8_t’ *note codecs: de7.
     (Contributed by Serhiy Storchaka in bpo-22682(4) and bpo-22681(5).)

   * Property docstrings are now writable.  This is especially useful
     for *note collections.namedtuple(): 1ca. docstrings.  (Contributed
     by Berker Peksag in bpo-24064(6).)

   * Circular imports involving relative imports are now supported.
     (Contributed by Brett Cannon and Antoine Pitrou in bpo-17636(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19676

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22286

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23681

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22682

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22681

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24064

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17636


File: python.info,  Node: New Modules<9>,  Next: Improved Modules<9>,  Prev: Other Language Changes<9>,  Up: What’s New In Python 3 5

1.9.4 New Modules
-----------------

* Menu:

* typing: typing<10>.
* zipapp: zipapp<2>.


File: python.info,  Node: typing<10>,  Next: zipapp<2>,  Up: New Modules<9>

1.9.4.1 typing
..............

The new *note typing: 104. *note provisional: b1c. module provides
standard definitions and tools for function type annotations.  See *note
Type Hints: d90. for more information.


File: python.info,  Node: zipapp<2>,  Prev: typing<10>,  Up: New Modules<9>

1.9.4.2 zipapp
..............

The new *note zipapp: 130. module (specified in PEP 441(1)) provides an
API and command line tool for creating executable Python Zip
Applications, which were introduced in Python 2.6 in bpo-1739468(2), but
which were not well publicized, either at the time or since.

With the new module, bundling your application is as simple as putting
all the files, including a ‘__main__.py’ file, into a directory ‘myapp’
and running:

     $ python -m zipapp myapp
     $ python myapp.pyz

The module implementation has been contributed by Paul Moore in
bpo-23491(3).

See also
........

PEP 441(4) – Improving Python ZIP Application Support

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0441/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1739468

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23491

   (4) https://peps.python.org/pep-0441/


File: python.info,  Node: Improved Modules<9>,  Next: Other module-level changes,  Prev: New Modules<9>,  Up: What’s New In Python 3 5

1.9.5 Improved Modules
----------------------

* Menu:

* argparse: argparse<4>.
* asyncio: asyncio<10>.
* bz2::
* cgi::
* cmath: cmath<2>.
* code::
* collections: collections<5>.
* collections.abc: collections abc<3>.
* compileall: compileall<4>.
* concurrent.futures: concurrent futures<5>.
* configparser: configparser<4>.
* contextlib: contextlib<5>.
* csv: csv<3>.
* curses: curses<4>.
* dbm: dbm<5>.
* difflib::
* distutils: distutils<7>.
* doctest: doctest<3>.
* email: email<3>.
* enum: enum<8>.
* faulthandler: faulthandler<3>.
* functools: functools<4>.
* glob: glob<3>.
* gzip: gzip<4>.
* heapq::
* http: http<2>.
* http.client: http client<3>.
* idlelib and IDLE: idlelib and IDLE<3>.
* imaplib: imaplib<2>.
* imghdr::
* importlib: importlib<8>.
* inspect: inspect<7>.
* io: io<5>.
* ipaddress: ipaddress<4>.
* json: json<2>.
* linecache: linecache<2>.
* locale: locale<6>.
* logging: logging<5>.
* lzma::
* math: math<8>.
* multiprocessing: multiprocessing<6>.
* operator: operator<2>.
* os: os<10>.
* pathlib: pathlib<10>.
* pickle: pickle<3>.
* poplib: poplib<2>.
* re: re<7>.
* readline: readline<2>.
* selectors::
* shutil: shutil<5>.
* signal: signal<3>.
* smtpd: smtpd<2>.
* smtplib: smtplib<2>.
* sndhdr::
* socket: socket<8>.
* ssl: ssl<9>.
* sqlite3: sqlite3<8>.
* subprocess: subprocess<4>.
* sys: sys<11>.
* sysconfig: sysconfig<2>.
* tarfile: tarfile<7>.
* threading: threading<6>.
* time: time<7>.
* timeit: timeit<2>.
* tkinter: tkinter<8>.
* traceback: traceback<5>.
* types: types<5>.
* unicodedata: unicodedata<8>.
* unittest: unittest<8>.
* unittest.mock: unittest mock<3>.
* urllib: urllib<2>.
* wsgiref::
* xmlrpc: xmlrpc<2>.
* xml.sax: xml sax.
* zipfile: zipfile<4>.


File: python.info,  Node: argparse<4>,  Next: asyncio<10>,  Up: Improved Modules<9>

1.9.5.1 argparse
................

The *note ArgumentParser: 53c. class now allows disabling *note
abbreviated usage: ded. of long options by setting *note allow_abbrev:
dee. to ‘False’.  (Contributed by Jonathan Paugh, Steven Bethard, paul
j3 and Daniel Eriksson in bpo-14910(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14910


File: python.info,  Node: asyncio<10>,  Next: bz2,  Prev: argparse<4>,  Up: Improved Modules<9>

1.9.5.2 asyncio
...............

Since the *note asyncio: a. module is *note provisional: b1c, all
changes introduced in Python 3.5 have also been backported to Python
3.4.x.

Notable changes in the *note asyncio: a. module since Python 3.4.0:

   * New debugging APIs: *note loop.set_debug(): df0. and *note
     loop.get_debug(): df1. methods.  (Contributed by Victor Stinner.)

   * The proactor event loop now supports SSL. (Contributed by Antoine
     Pitrou and Victor Stinner in bpo-22560(1).)

   * A new *note loop.is_closed(): df2. method to check if the event
     loop is closed.  (Contributed by Victor Stinner in bpo-21326(2).)

   * A new *note loop.create_task(): 1c0. to conveniently create and
     schedule a new *note Task: 1be. for a coroutine.  The ‘create_task’
     method is also used by all asyncio functions that wrap coroutines
     into tasks, such as *note asyncio.wait(): 482, *note
     asyncio.gather(): 600, etc.  (Contributed by Victor Stinner.)

   * A new *note transport.get_write_buffer_limits(): df3. method to
     inquire for 'high-' and 'low-' water limits of the flow control.
     (Contributed by Victor Stinner.)

   * The ‘async()’ function is deprecated in favor of *note
     ensure_future(): c98.  (Contributed by Yury Selivanov.)

   * New *note loop.set_task_factory(): df4. and *note
     loop.get_task_factory(): df5. methods to customize the task factory
     that *note loop.create_task(): 1c0. method uses.  (Contributed by
     Yury Selivanov.)

   * New *note Queue.join(): df6. and *note Queue.task_done(): df7.
     queue methods.  (Contributed by Victor Stinner.)

   * The ‘JoinableQueue’ class was removed, in favor of the *note
     asyncio.Queue: a85. class.  (Contributed by Victor Stinner.)

Updates in 3.5.1:

   * The *note ensure_future(): c98. function and all functions that use
     it, such as *note loop.run_until_complete(): c99, now accept all
     kinds of *note awaitable objects: 1ad.  (Contributed by Yury
     Selivanov.)

   * New *note run_coroutine_threadsafe(): 889. function to submit
     coroutines to event loops from other threads.  (Contributed by
     Vincent Michel.)

   * New *note Transport.is_closing(): c9a. method to check if the
     transport is closing or closed.  (Contributed by Yury Selivanov.)

   * The *note loop.create_server(): b2c. method can now accept a list
     of hosts.  (Contributed by Yann Sionneau.)

Updates in 3.5.2:

   * New *note loop.create_future(): c9b. method to create Future
     objects.  This allows alternative event loop implementations, such
     as uvloop(3), to provide a faster *note asyncio.Future: bec.
     implementation.  (Contributed by Yury Selivanov.)

   * New *note loop.get_exception_handler(): c9c. method to get the
     current exception handler.  (Contributed by Yury Selivanov.)

   * New *note StreamReader.readuntil(): 1b4. method to read data from
     the stream until a separator bytes sequence appears.  (Contributed
     by Mark Korenberg.)

   * The *note loop.create_connection(): 606. and *note
     loop.create_server(): b2c. methods are optimized to avoid calling
     the system ‘getaddrinfo’ function if the address is already
     resolved.  (Contributed by A. Jesse Jiryu Davis.)

   * The *note loop.sock_connect(sock, address): df8. no longer requires
     the 'address' to be resolved prior to the call.  (Contributed by A.
     Jesse Jiryu Davis.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22560

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21326

   (3) https://github.com/MagicStack/uvloop


File: python.info,  Node: bz2,  Next: cgi,  Prev: asyncio<10>,  Up: Improved Modules<9>

1.9.5.3 bz2
...........

The *note BZ2Decompressor.decompress: dfa. method now accepts an
optional 'max_length' argument to limit the maximum size of decompressed
data.  (Contributed by Nikolaus Rath in bpo-15955(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15955


File: python.info,  Node: cgi,  Next: cmath<2>,  Prev: bz2,  Up: Improved Modules<9>

1.9.5.4 cgi
...........

The ‘FieldStorage’ class now supports the *note context manager: 5d7.
protocol.  (Contributed by Berker Peksag in bpo-20289(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20289


File: python.info,  Node: cmath<2>,  Next: code,  Prev: cgi,  Up: Improved Modules<9>

1.9.5.5 cmath
.............

A new function *note isclose(): ddf. provides a way to test for
approximate equality.  (Contributed by Chris Barker and Tal Einat in
bpo-24270(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24270


File: python.info,  Node: code,  Next: collections<5>,  Prev: cmath<2>,  Up: Improved Modules<9>

1.9.5.6 code
............

The *note InteractiveInterpreter.showtraceback(): dfe. method now prints
the full chained traceback, just like the interactive interpreter.
(Contributed by Claudiu Popa in bpo-17442(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17442


File: python.info,  Node: collections<5>,  Next: collections abc<3>,  Prev: code,  Up: Improved Modules<9>

1.9.5.7 collections
...................

The *note OrderedDict: 5de. class is now implemented in C, which makes
it 4 to 100 times faster.  (Contributed by Eric Snow in bpo-16991(1).)

‘OrderedDict.items()’, ‘OrderedDict.keys()’, and ‘OrderedDict.values()’
views now support *note reversed(): 86c. iteration.  (Contributed by
Serhiy Storchaka in bpo-19505(2).)

The *note deque: 5df. class now defines *note index(): e00, *note
insert(): e01, and *note copy(): e02, and supports the ‘+’ and ‘*’
operators.  This allows deques to be recognized as a *note
MutableSequence: 1a1. and improves their substitutability for lists.
(Contributed by Raymond Hettinger in bpo-23704(3).)

Docstrings produced by *note namedtuple(): 1ca. can now be updated:

     Point = namedtuple('Point', ['x', 'y'])
     Point.__doc__ += ': Cartesian coordinate'
     Point.x.__doc__ = 'abscissa'
     Point.y.__doc__ = 'ordinate'

(Contributed by Berker Peksag in bpo-24064(4).)

The *note UserString: e03. class now implements the *note
__getnewargs__(): e04, *note __rmod__(): e05, *note casefold(): e06,
*note format_map(): e07, *note isprintable(): e08, and *note
maketrans(): e09. methods to match the corresponding methods of *note
str: 44f.  (Contributed by Joe Jevnik in bpo-22189(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16991

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19505

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23704

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24064

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22189


File: python.info,  Node: collections abc<3>,  Next: compileall<4>,  Prev: collections<5>,  Up: Improved Modules<9>

1.9.5.8 collections.abc
.......................

The ‘Sequence.index()’ method now accepts 'start' and 'stop' arguments
to match the corresponding methods of *note tuple: 373, *note list: 614,
etc.  (Contributed by Devin Jeanpierre in bpo-23086(1).)

A new *note Generator: e0b. abstract base class.  (Contributed by Stefan
Behnel in bpo-24018(2).)

New *note Awaitable: e0c, *note Coroutine: e0d, *note AsyncIterator:
e0e, and *note AsyncIterable: e0f. abstract base classes.  (Contributed
by Yury Selivanov in bpo-24184(3).)

For earlier Python versions, a backport of the new ABCs is available in
an external PyPI package(4).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23086

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24018

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24184

   (4) https://pypi.org/project/backports_abc/


File: python.info,  Node: compileall<4>,  Next: concurrent futures<5>,  Prev: collections abc<3>,  Up: Improved Modules<9>

1.9.5.9 compileall
..................

A new *note compileall: 20. option, ‘-j N’, allows running 'N' workers
simultaneously to perform parallel bytecode compilation.  The *note
compile_dir(): b3e. function has a corresponding ‘workers’ parameter.
(Contributed by Claudiu Popa in bpo-16104(1).)

Another new option, ‘-r’, allows controlling the maximum recursion level
for subdirectories.  (Contributed by Claudiu Popa in bpo-19628(2).)

The ‘-q’ command line option can now be specified more than once, in
which case all output, including errors, will be suppressed.  The
corresponding ‘quiet’ parameter in *note compile_dir(): b3e, *note
compile_file(): e11, and *note compile_path(): e12. can now accept an
integer value indicating the level of output suppression.  (Contributed
by Thomas Kluyver in bpo-21338(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16104

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19628

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21338


File: python.info,  Node: concurrent futures<5>,  Next: configparser<4>,  Prev: compileall<4>,  Up: Improved Modules<9>

1.9.5.10 concurrent.futures
...........................

The *note Executor.map(): e14. method now accepts a 'chunksize' argument
to allow batching of tasks to improve performance when *note
ProcessPoolExecutor(): 8f7. is used.  (Contributed by Dan O’Reilly in
bpo-11271(1).)

The number of workers in the *note ThreadPoolExecutor: 745. constructor
is optional now.  The default value is 5 times the number of CPUs.
(Contributed by Claudiu Popa in bpo-21527(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11271

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21527


File: python.info,  Node: configparser<4>,  Next: contextlib<5>,  Prev: concurrent futures<5>,  Up: Improved Modules<9>

1.9.5.11 configparser
.....................

*note configparser: 22. now provides a way to customize the conversion
of values by specifying a dictionary of converters in the *note
ConfigParser: 1c8. constructor, or by defining them as methods in
‘ConfigParser’ subclasses.  Converters defined in a parser instance are
inherited by its section proxies.

Example:

     >>> import configparser
     >>> conv = {}
     >>> conv['list'] = lambda v: [e.strip() for e in v.split() if e.strip()]
     >>> cfg = configparser.ConfigParser(converters=conv)
     >>> cfg.read_string("""
     ... [s]
     ... list = a b c d e f g
     ... """)
     >>> cfg.get('s', 'list')
     'a b c d e f g'
     >>> cfg.getlist('s', 'list')
     ['a', 'b', 'c', 'd', 'e', 'f', 'g']
     >>> section = cfg['s']
     >>> section.getlist('list')
     ['a', 'b', 'c', 'd', 'e', 'f', 'g']

(Contributed by Łukasz Langa in bpo-18159(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18159


File: python.info,  Node: contextlib<5>,  Next: csv<3>,  Prev: configparser<4>,  Up: Improved Modules<9>

1.9.5.12 contextlib
...................

The new *note redirect_stderr(): e17. *note context manager: 5d7.
(similar to *note redirect_stdout(): e18.) makes it easier for utility
scripts to handle inflexible APIs that write their output to *note
sys.stderr: 943. and don’t provide any options to redirect it:

     >>> import contextlib, io, logging
     >>> f = io.StringIO()
     >>> with contextlib.redirect_stderr(f):
     ...     logging.warning('warning')
     ...
     >>> f.getvalue()
     'WARNING:root:warning\n'

(Contributed by Berker Peksag in bpo-22389(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22389


File: python.info,  Node: csv<3>,  Next: curses<4>,  Prev: contextlib<5>,  Up: Improved Modules<9>

1.9.5.13 csv
............

The *note writerow(): e1a. method now supports arbitrary iterables, not
just sequences.  (Contributed by Serhiy Storchaka in bpo-23171(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23171


File: python.info,  Node: curses<4>,  Next: dbm<5>,  Prev: csv<3>,  Up: Improved Modules<9>

1.9.5.14 curses
...............

The new *note update_lines_cols(): e1c. function updates the *note
LINES: e1d. and *note COLS: e1e. module variables.  This is useful for
detecting manual screen resizing.  (Contributed by Arnon Yaari in
bpo-4254(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4254


File: python.info,  Node: dbm<5>,  Next: difflib,  Prev: curses<4>,  Up: Improved Modules<9>

1.9.5.15 dbm
............

*note dumb.open: aab. always creates a new database when the flag has
the value ‘"n"’.  (Contributed by Claudiu Popa in bpo-18039(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18039


File: python.info,  Node: difflib,  Next: distutils<7>,  Prev: dbm<5>,  Up: Improved Modules<9>

1.9.5.16 difflib
................

The charset of HTML documents generated by *note HtmlDiff.make_file():
e21. can now be customized by using a new 'charset' keyword-only
argument.  The default charset of HTML document changed from
‘"ISO-8859-1"’ to ‘"utf-8"’.  (Contributed by Berker Peksag in
bpo-2052(1).)

The *note diff_bytes(): e22. function can now compare lists of byte
strings.  This fixes a regression from Python 2.  (Contributed by Terry
J. Reedy and Greg Ward in bpo-17445(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2052

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17445


File: python.info,  Node: distutils<7>,  Next: doctest<3>,  Prev: difflib,  Up: Improved Modules<9>

1.9.5.17 distutils
..................

Both the ‘build’ and ‘build_ext’ commands now accept a ‘-j’ option to
enable parallel building of extension modules.  (Contributed by Antoine
Pitrou in bpo-5309(1).)

The ‘distutils’ module now supports ‘xz’ compression, and can be enabled
by passing ‘xztar’ as an argument to ‘bdist --format’.  (Contributed by
Serhiy Storchaka in bpo-16314(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5309

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16314


File: python.info,  Node: doctest<3>,  Next: email<3>,  Prev: distutils<7>,  Up: Improved Modules<9>

1.9.5.18 doctest
................

The *note DocTestSuite(): e25. function returns an empty *note
unittest.TestSuite: e26. if 'module' contains no docstrings, instead of
raising *note ValueError: 202.  (Contributed by Glenn Jones in
bpo-15916(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15916


File: python.info,  Node: email<3>,  Next: enum<8>,  Prev: doctest<3>,  Up: Improved Modules<9>

1.9.5.19 email
..............

A new policy option *note Policy.mangle_from_: e28. controls whether or
not lines that start with ‘"From "’ in email bodies are prefixed with a
‘">"’ character by generators.  The default is ‘True’ for *note
compat32: cbe. and ‘False’ for all other policies.  (Contributed by
Milan Oberkirch in bpo-20098(1).)

A new *note Message.get_content_disposition(): e29. method provides easy
access to a canonical value for the ‘Content-Disposition’ header.
(Contributed by Abhilash Raj in bpo-21083(2).)

A new policy option *note EmailPolicy.utf8: e2a. can be set to ‘True’ to
encode email headers using the UTF-8 charset instead of using encoded
words.  This allows ‘Messages’ to be formatted according to RFC 6532(3)
and used with an SMTP server that supports the RFC 6531(4) ‘SMTPUTF8’
extension.  (Contributed by R. David Murray in bpo-24211(5).)

The *note mime.text.MIMEText: e2b. constructor now accepts a *note
charset.Charset: e2c. instance.  (Contributed by Claude Paroz and Berker
Peksag in bpo-16324(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20098

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21083

   (3) https://datatracker.ietf.org/doc/html/rfc6532.html

   (4) https://datatracker.ietf.org/doc/html/rfc6531.html

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24211

   (6) https://bugs.python.org/issue?@action=redirect&bpo=16324


File: python.info,  Node: enum<8>,  Next: faulthandler<3>,  Prev: email<3>,  Up: Improved Modules<9>

1.9.5.20 enum
.............

The *note Enum: 633. callable has a new parameter 'start' to specify the
initial number of enum values if only 'names' are provided:

     >>> Animal = enum.Enum('Animal', 'cat dog', start=10)
     >>> Animal.cat
     <Animal.cat: 10>
     >>> Animal.dog
     <Animal.dog: 11>

(Contributed by Ethan Furman in bpo-21706(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21706


File: python.info,  Node: faulthandler<3>,  Next: functools<4>,  Prev: enum<8>,  Up: Improved Modules<9>

1.9.5.21 faulthandler
.....................

The *note enable(): cc4, *note register(): e2f, *note dump_traceback():
e30. and *note dump_traceback_later(): e31. functions now accept file
descriptors in addition to file-like objects.  (Contributed by Wei Wu in
bpo-23566(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23566


File: python.info,  Node: functools<4>,  Next: glob<3>,  Prev: faulthandler<3>,  Up: Improved Modules<9>

1.9.5.22 functools
..................

Most of the *note lru_cache(): 9fa. machinery is now implemented in C,
making it significantly faster.  (Contributed by Matt Joiner, Alexey
Kachayev, and Serhiy Storchaka in bpo-14373(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14373


File: python.info,  Node: glob<3>,  Next: gzip<4>,  Prev: functools<4>,  Up: Improved Modules<9>

1.9.5.23 glob
.............

The *note iglob(): 80d. and *note glob(): 29f. functions now support
recursive search in subdirectories, using the ‘"**"’ pattern.
(Contributed by Serhiy Storchaka in bpo-13968(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13968


File: python.info,  Node: gzip<4>,  Next: heapq,  Prev: glob<3>,  Up: Improved Modules<9>

1.9.5.24 gzip
.............

The 'mode' argument of the *note GzipFile: 41d. constructor now accepts
‘"x"’ to request exclusive creation.  (Contributed by Tim Heaney in
bpo-19222(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19222


File: python.info,  Node: heapq,  Next: http<2>,  Prev: gzip<4>,  Up: Improved Modules<9>

1.9.5.25 heapq
..............

Element comparison in *note merge(): e36. can now be customized by
passing a *note key function: e37. in a new optional 'key' keyword
argument, and a new optional 'reverse' keyword argument can be used to
reverse element comparison:

     >>> import heapq
     >>> a = ['9', '777', '55555']
     >>> b = ['88', '6666']
     >>> list(heapq.merge(a, b, key=len))
     ['9', '88', '777', '6666', '55555']
     >>> list(heapq.merge(reversed(a), reversed(b), key=len, reverse=True))
     ['55555', '6666', '777', '88', '9']

(Contributed by Raymond Hettinger in bpo-13742(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13742


File: python.info,  Node: http<2>,  Next: http client<3>,  Prev: heapq,  Up: Improved Modules<9>

1.9.5.26 http
.............

A new *note HTTPStatus: 909. enum that defines a set of HTTP status
codes, reason phrases and long descriptions written in English.
(Contributed by Demian Brecht in bpo-21793(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21793


File: python.info,  Node: http client<3>,  Next: idlelib and IDLE<3>,  Prev: http<2>,  Up: Improved Modules<9>

1.9.5.27 http.client
....................

*note HTTPConnection.getresponse(): e3a. now raises a *note
RemoteDisconnected: e3b. exception when a remote server connection is
closed unexpectedly.  Additionally, if a *note ConnectionError: e3c. (of
which ‘RemoteDisconnected’ is a subclass) is raised, the client socket
is now closed automatically, and will reconnect on the next request:

     import http.client
     conn = http.client.HTTPConnection('www.python.org')
     for retries in range(3):
         try:
             conn.request('GET', '/')
             resp = conn.getresponse()
         except http.client.RemoteDisconnected:
             pass

(Contributed by Martin Panter in bpo-3566(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3566


File: python.info,  Node: idlelib and IDLE<3>,  Next: imaplib<2>,  Prev: http client<3>,  Up: Improved Modules<9>

1.9.5.28 idlelib and IDLE
.........................

Since idlelib implements the IDLE shell and editor and is not intended
for import by other programs, it gets improvements with every release.
See ‘Lib/idlelib/NEWS.txt’ for a cumulative list of changes since 3.4.0,
as well as changes made in future 3.5.x releases.  This file is also
available from the IDLE Help ‣ About IDLE dialog.


File: python.info,  Node: imaplib<2>,  Next: imghdr,  Prev: idlelib and IDLE<3>,  Up: Improved Modules<9>

1.9.5.29 imaplib
................

The *note IMAP4: 90c. class now supports the *note context manager: 5d7.
protocol.  When used in a *note with: 5d5. statement, the IMAP4 ‘LOGOUT’
command will be called automatically at the end of the block.
(Contributed by Tarek Ziadé and Serhiy Storchaka in bpo-4972(1).)

The *note imaplib: 74. module now supports RFC 5161(2) (ENABLE
Extension) and RFC 6855(3) (UTF-8 Support) via the *note IMAP4.enable():
e3f. method.  A new *note IMAP4.utf8_enabled: e40. attribute tracks
whether or not RFC 6855(4) support is enabled.  (Contributed by Milan
Oberkirch, R. David Murray, and Maciej Szulik in bpo-21800(5).)

The *note imaplib: 74. module now automatically encodes non-ASCII string
usernames and passwords using UTF-8, as recommended by the RFCs.
(Contributed by Milan Oberkirch in bpo-21800(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4972

   (2) https://datatracker.ietf.org/doc/html/rfc5161.html

   (3) https://datatracker.ietf.org/doc/html/rfc6855.html

   (4) https://datatracker.ietf.org/doc/html/rfc6855.html

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21800

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21800


File: python.info,  Node: imghdr,  Next: importlib<8>,  Prev: imaplib<2>,  Up: Improved Modules<9>

1.9.5.30 imghdr
...............

The ‘what()’ function now recognizes the OpenEXR(1) format (contributed
by Martin Vignali and Claudiu Popa in bpo-20295(2)), and the WebP(3)
format (contributed by Fabrice Aneche and Claudiu Popa in bpo-20197(4).)

   ---------- Footnotes ----------

   (1) https://www.openexr.com

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20295

   (3) https://en.wikipedia.org/wiki/WebP

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20197


File: python.info,  Node: importlib<8>,  Next: inspect<7>,  Prev: imghdr,  Up: Improved Modules<9>

1.9.5.31 importlib
..................

The *note util.LazyLoader: cd3. class allows for lazy loading of modules
in applications where startup time is important.  (Contributed by Brett
Cannon in bpo-17621(1).)

The *note abc.InspectLoader.source_to_code(): e43. method is now a
static method.  This makes it easier to initialize a module object with
code compiled from a string by running ‘exec(code, module.__dict__)’.
(Contributed by Brett Cannon in bpo-21156(2).)

The new *note util.module_from_spec(): e44. function is now the
preferred way to create a new module.  As opposed to creating a *note
types.ModuleType: e45. instance directly, this new function will set the
various import-controlled attributes based on the passed-in spec object.
(Contributed by Brett Cannon in bpo-20383(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17621

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21156

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20383


File: python.info,  Node: inspect<7>,  Next: io<5>,  Prev: importlib<8>,  Up: Improved Modules<9>

1.9.5.32 inspect
................

Both the *note Signature: 1cf. and *note Parameter: 1d0. classes are now
picklable and hashable.  (Contributed by Yury Selivanov in bpo-20726(1)
and bpo-20334(2).)

A new *note BoundArguments.apply_defaults(): e47. method provides a way
to set default values for missing arguments:

     >>> def foo(a, b='ham', *args): pass
     >>> ba = inspect.signature(foo).bind('spam')
     >>> ba.apply_defaults()
     >>> ba.arguments
     OrderedDict([('a', 'spam'), ('b', 'ham'), ('args', ())])

(Contributed by Yury Selivanov in bpo-24190(3).)

A new class method *note Signature.from_callable(): 73d. makes
subclassing of *note Signature: 1cf. easier.  (Contributed by Yury
Selivanov and Eric Snow in bpo-17373(4).)

The *note signature(): 73b. function now accepts a 'follow_wrapped'
optional keyword argument, which, when set to ‘False’, disables
automatic following of ‘__wrapped__’ links.  (Contributed by Yury
Selivanov in bpo-20691(5).)

A set of new functions to inspect *note coroutine functions: da1. and
*note coroutine objects: 494. has been added: *note iscoroutine(): e48,
*note iscoroutinefunction(): 2e4, *note isawaitable(): e49, *note
getcoroutinelocals(): e4a, and *note getcoroutinestate(): e4b.
(Contributed by Yury Selivanov in bpo-24017(6) and bpo-24400(7).)

The *note stack(): 655, *note trace(): 656, *note getouterframes(): 653,
and *note getinnerframes(): 654. functions now return a list of named
tuples.  (Contributed by Daniel Shahaf in bpo-16808(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20726

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20334

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24190

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17373

   (5) https://bugs.python.org/issue?@action=redirect&bpo=20691

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24017

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24400

   (8) https://bugs.python.org/issue?@action=redirect&bpo=16808


File: python.info,  Node: io<5>,  Next: ipaddress<4>,  Prev: inspect<7>,  Up: Improved Modules<9>

1.9.5.33 io
...........

A new *note BufferedIOBase.readinto1(): e4d. method, that uses at most
one call to the underlying raw stream’s *note RawIOBase.read(): e4e. or
*note RawIOBase.readinto(): e4f. methods.  (Contributed by Nikolaus Rath
in bpo-20578(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20578


File: python.info,  Node: ipaddress<4>,  Next: json<2>,  Prev: io<5>,  Up: Improved Modules<9>

1.9.5.34 ipaddress
..................

Both the *note IPv4Network: 1fe. and *note IPv6Network: 1ff. classes now
accept an ‘(address, netmask)’ tuple argument, so as to easily construct
network objects from existing addresses:

     >>> import ipaddress
     >>> ipaddress.IPv4Network(('127.0.0.0', 8))
     IPv4Network('127.0.0.0/8')
     >>> ipaddress.IPv4Network(('127.0.0.0', '255.0.0.0'))
     IPv4Network('127.0.0.0/8')

(Contributed by Peter Moody and Antoine Pitrou in bpo-16531(1).)

A new *note reverse_pointer: e51. attribute for the *note IPv4Address:
1fc. and *note IPv6Address: 1fd. classes returns the name of the reverse
DNS PTR record:

     >>> import ipaddress
     >>> addr = ipaddress.IPv4Address('127.0.0.1')
     >>> addr.reverse_pointer
     '1.0.0.127.in-addr.arpa'
     >>> addr6 = ipaddress.IPv6Address('::1')
     >>> addr6.reverse_pointer
     '1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa'

(Contributed by Leon Weber in bpo-20480(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16531

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20480


File: python.info,  Node: json<2>,  Next: linecache<2>,  Prev: ipaddress<4>,  Up: Improved Modules<9>

1.9.5.35 json
.............

The *note json.tool: 83. command line interface now preserves the order
of keys in JSON objects passed in input.  The new ‘--sort-keys’ option
can be used to sort the keys alphabetically.  (Contributed by Berker
Peksag in bpo-21650(1).)

JSON decoder now raises *note JSONDecodeError: e53. instead of *note
ValueError: 202. to provide better context information about the error.
(Contributed by Serhiy Storchaka in bpo-19361(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21650

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19361


File: python.info,  Node: linecache<2>,  Next: locale<6>,  Prev: json<2>,  Up: Improved Modules<9>

1.9.5.36 linecache
..................

A new *note lazycache(): e55. function can be used to capture
information about a non-file-based module to permit getting its lines
later via *note getline(): e56.  This avoids doing I/O until a line is
actually needed, without having to carry the module globals around
indefinitely.  (Contributed by Robert Collins in bpo-17911(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17911


File: python.info,  Node: locale<6>,  Next: logging<5>,  Prev: linecache<2>,  Up: Improved Modules<9>

1.9.5.37 locale
...............

A new *note delocalize(): e58. function can be used to convert a string
into a normalized number string, taking the ‘LC_NUMERIC’ settings into
account:

     >>> import locale
     >>> locale.setlocale(locale.LC_NUMERIC, 'de_DE.UTF-8')
     'de_DE.UTF-8'
     >>> locale.delocalize('1.234,56')
     '1234.56'
     >>> locale.setlocale(locale.LC_NUMERIC, 'en_US.UTF-8')
     'en_US.UTF-8'
     >>> locale.delocalize('1,234.56')
     '1234.56'

(Contributed by Cédric Krier in bpo-13918(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13918


File: python.info,  Node: logging<5>,  Next: lzma,  Prev: locale<6>,  Up: Improved Modules<9>

1.9.5.38 logging
................

All logging methods (*note Logger: b6a. *note log(): e5a, *note
exception(): e5b, *note critical(): e5c, *note debug(): e5d, etc.), now
accept exception instances as an 'exc_info' argument, in addition to
boolean values and exception tuples:

     >>> import logging
     >>> try:
     ...     1/0
     ... except ZeroDivisionError as ex:
     ...     logging.error('exception', exc_info=ex)
     ERROR:root:exception

(Contributed by Yury Selivanov in bpo-20537(1).)

The *note handlers.HTTPHandler: e5e. class now accepts an optional *note
ssl.SSLContext: 294. instance to configure SSL settings used in an HTTP
connection.  (Contributed by Alex Gaynor in bpo-22788(2).)

The *note handlers.QueueListener: e5f. class now takes a
'respect_handler_level' keyword argument which, if set to ‘True’, will
pass messages to handlers taking handler levels into account.
(Contributed by Vinay Sajip.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20537

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22788


File: python.info,  Node: lzma,  Next: math<8>,  Prev: logging<5>,  Up: Improved Modules<9>

1.9.5.39 lzma
.............

The *note LZMADecompressor.decompress(): e61. method now accepts an
optional 'max_length' argument to limit the maximum size of decompressed
data.  (Contributed by Martin Panter in bpo-15955(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15955


File: python.info,  Node: math<8>,  Next: multiprocessing<6>,  Prev: lzma,  Up: Improved Modules<9>

1.9.5.40 math
.............

Two new constants have been added to the *note math: 8e. module: *note
inf: ca7. and *note nan: 666.  (Contributed by Mark Dickinson in
bpo-23185(1).)

A new function *note isclose(): dde. provides a way to test for
approximate equality.  (Contributed by Chris Barker and Tal Einat in
bpo-24270(2).)

A new *note gcd(): 919. function has been added.  The ‘fractions.gcd()’
function is now deprecated.  (Contributed by Mark Dickinson and Serhiy
Storchaka in bpo-22486(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23185

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24270

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22486


File: python.info,  Node: multiprocessing<6>,  Next: operator<2>,  Prev: math<8>,  Up: Improved Modules<9>

1.9.5.41 multiprocessing
........................

*note sharedctypes.synchronized(): e64. objects now support the *note
context manager: 5d7. protocol.  (Contributed by Charles-François Natali
in bpo-21565(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21565


File: python.info,  Node: operator<2>,  Next: os<10>,  Prev: multiprocessing<6>,  Up: Improved Modules<9>

1.9.5.42 operator
.................

*note attrgetter(): e66, *note itemgetter(): a70, and *note
methodcaller(): e67. objects now support pickling.  (Contributed by Josh
Rosenberg and Serhiy Storchaka in bpo-22955(1).)

New *note matmul(): e68. and *note imatmul(): e69. functions to perform
matrix multiplication.  (Contributed by Benjamin Peterson in
bpo-21176(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22955

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21176


File: python.info,  Node: os<10>,  Next: pathlib<10>,  Prev: operator<2>,  Up: Improved Modules<9>

1.9.5.43 os
...........

The new *note scandir(): a6d. function returning an iterator of *note
DirEntry: 49e. objects has been added.  If possible, ‘scandir()’
extracts file attributes while scanning a directory, removing the need
to perform subsequent system calls to determine file type or attributes,
which may significantly improve performance.  (Contributed by Ben Hoyt
with the help of Victor Stinner in bpo-22524(1).)

On Windows, a new *note stat_result.st_file_attributes: e6b. attribute
is now available.  It corresponds to the ‘dwFileAttributes’ member of
the ‘BY_HANDLE_FILE_INFORMATION’ structure returned by
‘GetFileInformationByHandle()’.  (Contributed by Ben Hoyt in
bpo-21719(2).)

The *note urandom(): 526. function now uses the ‘getrandom()’ syscall on
Linux 3.17 or newer, and ‘getentropy()’ on OpenBSD 5.6 and newer,
removing the need to use ‘/dev/urandom’ and avoiding failures due to
potential file descriptor exhaustion.  (Contributed by Victor Stinner in
bpo-22181(3).)

New *note get_blocking(): e6c. and *note set_blocking(): e6d. functions
allow getting and setting a file descriptor’s blocking mode (*note
O_NONBLOCK: e6e.)  (Contributed by Victor Stinner in bpo-22054(4).)

The *note truncate(): e6f. and *note ftruncate(): dbd. functions are now
supported on Windows.  (Contributed by Steve Dower in bpo-23668(5).)

There is a new *note os.path.commonpath(): e70. function returning the
longest common sub-path of each passed pathname.  Unlike the *note
os.path.commonprefix(): e71. function, it always returns a valid path:

     >>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])
     '/usr/l'

     >>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])
     '/usr'

(Contributed by Rafik Draoui and Serhiy Storchaka in bpo-10395(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22524

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21719

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22181

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22054

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23668

   (6) https://bugs.python.org/issue?@action=redirect&bpo=10395


File: python.info,  Node: pathlib<10>,  Next: pickle<3>,  Prev: os<10>,  Up: Improved Modules<9>

1.9.5.44 pathlib
................

The new *note Path.samefile(): e73. method can be used to check whether
the path points to the same file as another path, which can be either
another *note Path: 229. object, or a string:

     >>> import pathlib
     >>> p1 = pathlib.Path('/etc/hosts')
     >>> p2 = pathlib.Path('/etc/../etc/hosts')
     >>> p1.samefile(p2)
     True

(Contributed by Vajrasky Kok and Antoine Pitrou in bpo-19775(1).)

The *note Path.mkdir(): e74. method now accepts a new optional
'exist_ok' argument to match ‘mkdir -p’ and *note os.makedirs(): 21e.
functionality.  (Contributed by Berker Peksag in bpo-21539(2).)

There is a new *note Path.expanduser(): e75. method to expand ‘~’ and
‘~user’ prefixes.  (Contributed by Serhiy Storchaka and Claudiu Popa in
bpo-19776(3).)

A new *note Path.home(): e76. class method can be used to get a *note
Path: 229. instance representing the user’s home directory.
(Contributed by Victor Salgado and Mayank Tripathi in bpo-19777(4).)

New *note Path.write_text(): e77, *note Path.read_text(): e78, *note
Path.write_bytes(): e79, *note Path.read_bytes(): e7a. methods to
simplify read/write operations on files.

The following code snippet will create or rewrite existing file
‘~/spam42’:

     >>> import pathlib
     >>> p = pathlib.Path('~/spam42')
     >>> p.expanduser().write_text('ham')
     3

(Contributed by Christopher Welborn in bpo-20218(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19775

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21539

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19776

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19777

   (5) https://bugs.python.org/issue?@action=redirect&bpo=20218


File: python.info,  Node: pickle<3>,  Next: poplib<2>,  Prev: pathlib<10>,  Up: Improved Modules<9>

1.9.5.45 pickle
...............

Nested objects, such as unbound methods or nested classes, can now be
pickled using *note pickle protocols: ce7. older than protocol version
4.  Protocol version 4 already supports these cases.  (Contributed by
Serhiy Storchaka in bpo-23611(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23611


File: python.info,  Node: poplib<2>,  Next: re<7>,  Prev: pickle<3>,  Up: Improved Modules<9>

1.9.5.46 poplib
...............

A new *note POP3.utf8(): e7d. command enables RFC 6856(1)
(Internationalized Email) support, if a POP server supports it.
(Contributed by Milan OberKirch in bpo-21804(2).)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc6856.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21804


File: python.info,  Node: re<7>,  Next: readline<2>,  Prev: poplib<2>,  Up: Improved Modules<9>

1.9.5.47 re
...........

References and conditional references to groups with fixed length are
now allowed in lookbehind assertions:

     >>> import re
     >>> pat = re.compile(r'(a|b).(?<=\1)c')
     >>> pat.match('aac')
     <_sre.SRE_Match object; span=(0, 3), match='aac'>
     >>> pat.match('bbc')
     <_sre.SRE_Match object; span=(0, 3), match='bbc'>

(Contributed by Serhiy Storchaka in bpo-9179(1).)

The number of capturing groups in regular expressions is no longer
limited to 100.  (Contributed by Serhiy Storchaka in bpo-22437(2).)

The *note sub(): 2a3. and *note subn(): 2a4. functions now replace
unmatched groups with empty strings instead of raising an exception.
(Contributed by Serhiy Storchaka in bpo-1519638(3).)

The *note re.error: 23e. exceptions have new attributes, *note msg: e7f,
*note pattern: e80, *note pos: e81, *note lineno: e82, and *note colno:
e83, that provide better context information about the error:

     >>> re.compile("""
     ...     (?x)
     ...     .++
     ... """)
     Traceback (most recent call last):
        ...
     sre_constants.error: multiple repeat at position 16 (line 3, column 7)

(Contributed by Serhiy Storchaka in bpo-22578(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9179

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22437

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1519638

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22578


File: python.info,  Node: readline<2>,  Next: selectors,  Prev: re<7>,  Up: Improved Modules<9>

1.9.5.48 readline
.................

A new *note append_history_file(): e85. function can be used to append
the specified number of trailing elements in history to the given file.
(Contributed by Bruno Cauet in bpo-22940(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22940


File: python.info,  Node: selectors,  Next: shutil<5>,  Prev: readline<2>,  Up: Improved Modules<9>

1.9.5.49 selectors
..................

The new *note DevpollSelector: bf8. supports efficient ‘/dev/poll’
polling on Solaris.  (Contributed by Giampaolo Rodola’ in bpo-18931(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18931


File: python.info,  Node: shutil<5>,  Next: signal<3>,  Prev: selectors,  Up: Improved Modules<9>

1.9.5.50 shutil
...............

The *note move(): a6a. function now accepts a 'copy_function' argument,
allowing, for example, the *note copy(): a68. function to be used
instead of the default *note copy2(): a69. if there is a need to ignore
file metadata when moving.  (Contributed by Claudiu Popa in
bpo-19840(1).)

The *note make_archive(): 4b6. function now supports the 'xztar' format.
(Contributed by Serhiy Storchaka in bpo-5411(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19840

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5411


File: python.info,  Node: signal<3>,  Next: smtpd<2>,  Prev: shutil<5>,  Up: Improved Modules<9>

1.9.5.51 signal
...............

On Windows, the *note set_wakeup_fd(): b8c. function now also supports
socket handles.  (Contributed by Victor Stinner in bpo-22018(1).)

Various ‘SIG*’ constants in the *note signal: c6. module have been
converted into *note Enums: 56.  This allows meaningful names to be
printed during debugging, instead of integer “magic numbers”.
(Contributed by Giampaolo Rodola’ in bpo-21076(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22018

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21076


File: python.info,  Node: smtpd<2>,  Next: smtplib<2>,  Prev: signal<3>,  Up: Improved Modules<9>

1.9.5.52 smtpd
..............

Both the ‘SMTPServer’ and ‘SMTPChannel’ classes now accept a
'decode_data' keyword argument to determine if the ‘DATA’ portion of the
SMTP transaction is decoded using the ‘"utf-8"’ codec or is instead
provided to the ‘SMTPServer.process_message()’ method as a byte string.
The default is ‘True’ for backward compatibility reasons, but will
change to ‘False’ in Python 3.6.  If 'decode_data' is set to ‘False’,
the ‘process_message’ method must be prepared to accept keyword
arguments.  (Contributed by Maciej Szulik in bpo-19662(1).)

The ‘SMTPServer’ class now advertises the ‘8BITMIME’ extension ( RFC
6152(2)) if 'decode_data' has been set ‘True’.  If the client specifies
‘BODY=8BITMIME’ on the ‘MAIL’ command, it is passed to
‘SMTPServer.process_message()’ via the 'mail_options' keyword.
(Contributed by Milan Oberkirch and R. David Murray in bpo-21795(3).)

The ‘SMTPServer’ class now also supports the ‘SMTPUTF8’ extension ( RFC
6531(4): Internationalized Email).  If the client specified ‘SMTPUTF8
BODY=8BITMIME’ on the ‘MAIL’ command, they are passed to
‘SMTPServer.process_message()’ via the 'mail_options' keyword.  It is
the responsibility of the ‘process_message’ method to correctly handle
the ‘SMTPUTF8’ data.  (Contributed by Milan Oberkirch in bpo-21725(5).)

It is now possible to provide, directly or via name resolution, IPv6
addresses in the ‘SMTPServer’ constructor, and have it successfully
connect.  (Contributed by Milan Oberkirch in bpo-14758(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19662

   (2) https://datatracker.ietf.org/doc/html/rfc6152.html

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21795

   (4) https://datatracker.ietf.org/doc/html/rfc6531.html

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21725

   (6) https://bugs.python.org/issue?@action=redirect&bpo=14758


File: python.info,  Node: smtplib<2>,  Next: sndhdr,  Prev: smtpd<2>,  Up: Improved Modules<9>

1.9.5.53 smtplib
................

A new *note SMTP.auth(): e8b. method provides a convenient way to
implement custom authentication mechanisms.  (Contributed by Milan
Oberkirch in bpo-15014(1).)

The *note SMTP.set_debuglevel(): e8c. method now accepts an additional
debuglevel (2), which enables timestamps in debug messages.
(Contributed by Gavin Chappell and Maciej Szulik in bpo-16914(2).)

Both the *note SMTP.sendmail(): e8d. and *note SMTP.send_message(): e8e.
methods now support RFC 6531(3) (SMTPUTF8).  (Contributed by Milan
Oberkirch and R. David Murray in bpo-22027(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15014

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16914

   (3) https://datatracker.ietf.org/doc/html/rfc6531.html

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22027


File: python.info,  Node: sndhdr,  Next: socket<8>,  Prev: smtplib<2>,  Up: Improved Modules<9>

1.9.5.54 sndhdr
...............

The ‘what()’ and ‘whathdr()’ functions now return a *note namedtuple():
1ca.  (Contributed by Claudiu Popa in bpo-18615(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18615


File: python.info,  Node: socket<8>,  Next: ssl<9>,  Prev: sndhdr,  Up: Improved Modules<9>

1.9.5.55 socket
...............

Functions with timeouts now use a monotonic clock, instead of a system
clock.  (Contributed by Victor Stinner in bpo-22043(1).)

A new *note socket.sendfile(): e91. method allows sending a file over a
socket by using the high-performance *note os.sendfile(): b28. function
on UNIX, resulting in uploads being from 2 to 3 times faster than when
using plain *note socket.send(): dd5.  (Contributed by Giampaolo Rodola’
in bpo-17552(2).)

The *note socket.sendall(): dd6. method no longer resets the socket
timeout every time bytes are received or sent.  The socket timeout is
now the maximum total duration to send all data.  (Contributed by Victor
Stinner in bpo-23853(3).)

The 'backlog' argument of the *note socket.listen(): e92. method is now
optional.  By default it is set to *note SOMAXCONN: e93. or to ‘128’,
whichever is less.  (Contributed by Charles-François Natali in
bpo-21455(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22043

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17552

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23853

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21455


File: python.info,  Node: ssl<9>,  Next: sqlite3<8>,  Prev: socket<8>,  Up: Improved Modules<9>

1.9.5.56 ssl
............

* Menu:

* Memory BIO Support::
* Application-Layer Protocol Negotiation Support::
* Other Changes::


File: python.info,  Node: Memory BIO Support,  Next: Application-Layer Protocol Negotiation Support,  Up: ssl<9>

1.9.5.57 Memory BIO Support
...........................

(Contributed by Geert Jansen in bpo-21965(1).)

The new *note SSLObject: b9f. class has been added to provide SSL
protocol support for cases when the network I/O capabilities of *note
SSLSocket: 8f3. are not necessary or are suboptimal.  ‘SSLObject’
represents an SSL protocol instance, but does not implement any network
I/O methods, and instead provides a memory buffer interface.  The new
*note MemoryBIO: e96. class can be used to pass data between Python and
an SSL protocol instance.

The memory BIO SSL support is primarily intended to be used in
frameworks implementing asynchronous I/O for which *note SSLSocket:
8f3.’s readiness model (“select/poll”) is inefficient.

A new *note SSLContext.wrap_bio(): ba0. method can be used to create a
new ‘SSLObject’ instance.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21965


File: python.info,  Node: Application-Layer Protocol Negotiation Support,  Next: Other Changes,  Prev: Memory BIO Support,  Up: ssl<9>

1.9.5.58 Application-Layer Protocol Negotiation Support
.......................................................

(Contributed by Benjamin Peterson in bpo-20188(1).)

Where OpenSSL support is present, the *note ssl: d0. module now
implements the 'Application-Layer Protocol Negotiation' TLS extension as
described in RFC 7301(2).

The new *note SSLContext.set_alpn_protocols(): e98. can be used to
specify which protocols a socket should advertise during the TLS
handshake.

The new *note SSLSocket.selected_alpn_protocol(): e99. returns the
protocol that was selected during the TLS handshake.  The *note
HAS_ALPN: e9a. flag indicates whether ALPN support is present.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20188

   (2) https://datatracker.ietf.org/doc/html/rfc7301.html


File: python.info,  Node: Other Changes,  Prev: Application-Layer Protocol Negotiation Support,  Up: ssl<9>

1.9.5.59 Other Changes
......................

There is a new *note SSLSocket.version(): e9c. method to query the
actual protocol version in use.  (Contributed by Antoine Pitrou in
bpo-20421(1).)

The *note SSLSocket: 8f3. class now implements a ‘SSLSocket.sendfile()’
method.  (Contributed by Giampaolo Rodola’ in bpo-17552(2).)

The ‘SSLSocket.send()’ method now raises either the *note
ssl.SSLWantReadError: e9d. or *note ssl.SSLWantWriteError: e9e.
exception on a non-blocking socket if the operation would block.
Previously, it would return ‘0’.  (Contributed by Nikolaus Rath in
bpo-20951(3).)

The *note cert_time_to_seconds(): e9f. function now interprets the input
time as UTC and not as local time, per RFC 5280(4).  Additionally, the
return value is always an *note int: 257.  (Contributed by Akira Li in
bpo-19940(5).)

New ‘SSLObject.shared_ciphers()’ and *note SSLSocket.shared_ciphers():
ea0. methods return the list of ciphers sent by the client during the
handshake.  (Contributed by Benjamin Peterson in bpo-23186(6).)

The *note SSLSocket.do_handshake(): ea1, *note SSLSocket.read(): ea2,
‘SSLSocket.shutdown()’, and *note SSLSocket.write(): ea3. methods of the
*note SSLSocket: 8f3. class no longer reset the socket timeout every
time bytes are received or sent.  The socket timeout is now the maximum
total duration of the method.  (Contributed by Victor Stinner in
bpo-23853(7).)

The ‘match_hostname()’ function now supports matching of IP addresses.
(Contributed by Antoine Pitrou in bpo-23239(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20421

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17552

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20951

   (4) https://datatracker.ietf.org/doc/html/rfc5280.html

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19940

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23186

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23853

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23239


File: python.info,  Node: sqlite3<8>,  Next: subprocess<4>,  Prev: ssl<9>,  Up: Improved Modules<9>

1.9.5.60 sqlite3
................

The *note Row: ea5. class now fully supports the sequence protocol, in
particular *note reversed(): 86c. iteration and slice indexing.
(Contributed by Claudiu Popa in bpo-10203(1); by Lucas Sinclair, Jessica
McKellar, and Serhiy Storchaka in bpo-13583(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10203

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13583


File: python.info,  Node: subprocess<4>,  Next: sys<11>,  Prev: sqlite3<8>,  Up: Improved Modules<9>

1.9.5.61 subprocess
...................

The new *note run(): ba4. function has been added.  It runs the
specified command and returns a *note CompletedProcess: ea7. object,
which describes a finished process.  The new API is more consistent and
is the recommended approach to invoking subprocesses in Python code that
does not need to maintain compatibility with earlier Python versions.
(Contributed by Thomas Kluyver in bpo-23342(1).)

Examples:

     >>> subprocess.run(["ls", "-l"])  # doesn't capture output
     CompletedProcess(args=['ls', '-l'], returncode=0)

     >>> subprocess.run("exit 1", shell=True, check=True)
     Traceback (most recent call last):
       ...
     subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

     >>> subprocess.run(["ls", "-l", "/dev/null"], stdout=subprocess.PIPE)
     CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
     stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n')

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23342


File: python.info,  Node: sys<11>,  Next: sysconfig<2>,  Prev: subprocess<4>,  Up: Improved Modules<9>

1.9.5.62 sys
............

A new ‘set_coroutine_wrapper()’ function allows setting a global hook
that will be called whenever a *note coroutine object: 494. is created
by an *note async def: 5d4. function.  A corresponding
‘get_coroutine_wrapper()’ can be used to obtain a currently set wrapper.
Both functions are *note provisional: b1c, and are intended for
debugging purposes only.  (Contributed by Yury Selivanov in
bpo-24017(1).)

A new *note is_finalizing(): a9e. function can be used to check if the
Python interpreter is *note shutting down: 14e.  (Contributed by Antoine
Pitrou in bpo-22696(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24017

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22696


File: python.info,  Node: sysconfig<2>,  Next: tarfile<7>,  Prev: sys<11>,  Up: Improved Modules<9>

1.9.5.63 sysconfig
..................

The name of the user scripts directory on Windows now includes the first
two components of the Python version.  (Contributed by Paul Moore in
bpo-23437(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23437


File: python.info,  Node: tarfile<7>,  Next: threading<6>,  Prev: sysconfig<2>,  Up: Improved Modules<9>

1.9.5.64 tarfile
................

The 'mode' argument of the *note open(): eab. function now accepts ‘"x"’
to request exclusive creation.  (Contributed by Berker Peksag in
bpo-21717(1).)

The *note TarFile.extractall(): 431. and *note TarFile.extract(): 432.
methods now take a keyword argument 'numeric_owner'.  If set to ‘True’,
the extracted files and directories will be owned by the numeric ‘uid’
and ‘gid’ from the tarfile.  If set to ‘False’ (the default, and the
behavior in versions prior to 3.5), they will be owned by the named user
and group in the tarfile.  (Contributed by Michael Vogt and Eric Smith
in bpo-23193(2).)

The *note TarFile.list(): eac. now accepts an optional 'members' keyword
argument that can be set to a subset of the list returned by *note
TarFile.getmembers(): ead.  (Contributed by Serhiy Storchaka in
bpo-21549(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21717

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23193

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21549


File: python.info,  Node: threading<6>,  Next: time<7>,  Prev: tarfile<7>,  Up: Improved Modules<9>

1.9.5.65 threading
..................

Both the *note Lock.acquire(): 69b. and *note RLock.acquire(): eaf.
methods now use a monotonic clock for timeout management.  (Contributed
by Victor Stinner in bpo-22043(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22043


File: python.info,  Node: time<7>,  Next: timeit<2>,  Prev: threading<6>,  Up: Improved Modules<9>

1.9.5.66 time
.............

The *note monotonic(): 253. function is now always available.
(Contributed by Victor Stinner in bpo-22043(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22043


File: python.info,  Node: timeit<2>,  Next: tkinter<8>,  Prev: time<7>,  Up: Improved Modules<9>

1.9.5.67 timeit
...............

A new command line option ‘-u’ or ‘--unit=U’ can be used to specify the
time unit for the timer output.  Supported options are ‘usec’, ‘msec’,
or ‘sec’.  (Contributed by Julian Gindi in bpo-18983(1).)

The *note timeit(): eb2. function has a new 'globals' parameter for
specifying the namespace in which the code will be running.
(Contributed by Ben Roberts in bpo-2527(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18983

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2527


File: python.info,  Node: tkinter<8>,  Next: traceback<5>,  Prev: timeit<2>,  Up: Improved Modules<9>

1.9.5.68 tkinter
................

The ‘tkinter._fix’ module used for setting up the Tcl/Tk environment on
Windows has been replaced by a private function in the ‘_tkinter’ module
which makes no permanent changes to environment variables.  (Contributed
by Zachary Ware in bpo-20035(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20035


File: python.info,  Node: traceback<5>,  Next: types<5>,  Prev: tkinter<8>,  Up: Improved Modules<9>

1.9.5.69 traceback
..................

New *note walk_stack(): eb5. and *note walk_tb(): eb6. functions to
conveniently traverse frame and *note traceback objects: b0d.
(Contributed by Robert Collins in bpo-17911(1).)

New lightweight classes: *note TracebackException: 25c, *note
StackSummary: eb7, and *note FrameSummary: eb8.  (Contributed by Robert
Collins in bpo-17911(2).)

Both the *note print_tb(): eb9. and *note print_stack(): eba. functions
now support negative values for the 'limit' argument.  (Contributed by
Dmitry Kazakov in bpo-22619(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17911

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17911

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22619


File: python.info,  Node: types<5>,  Next: unicodedata<8>,  Prev: traceback<5>,  Up: Improved Modules<9>

1.9.5.70 types
..............

A new *note coroutine(): ebc. function to transform *note generator:
bff. and *note generator-like: e0b. objects into *note awaitables: 1ad.
(Contributed by Yury Selivanov in bpo-24017(1).)

A new type called *note CoroutineType: ebd, which is used for *note
coroutine: 494. objects created by *note async def: 5d4. functions.
(Contributed by Yury Selivanov in bpo-24400(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24017

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24400


File: python.info,  Node: unicodedata<8>,  Next: unittest<8>,  Prev: types<5>,  Up: Improved Modules<9>

1.9.5.71 unicodedata
....................

The *note unicodedata: 105. module now uses data from Unicode 8.0.0(1).

   ---------- Footnotes ----------

   (1) https://unicode.org/versions/Unicode8.0.0/


File: python.info,  Node: unittest<8>,  Next: unittest mock<3>,  Prev: unicodedata<8>,  Up: Improved Modules<9>

1.9.5.72 unittest
.................

The *note TestLoader.loadTestsFromModule(): 28f. method now accepts a
keyword-only argument 'pattern' which is passed to ‘load_tests’ as the
third argument.  Found packages are now checked for ‘load_tests’
regardless of whether their path matches 'pattern', because it is
impossible for a package name to match the default pattern.
(Contributed by Robert Collins and Barry A. Warsaw in bpo-16662(1).)

Unittest discovery errors now are exposed in the *note
TestLoader.errors: ec0. attribute of the *note TestLoader: 28e.
instance.  (Contributed by Robert Collins in bpo-19746(2).)

A new command line option ‘--locals’ to show local variables in
tracebacks.  (Contributed by Robert Collins in bpo-22936(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16662

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19746

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22936


File: python.info,  Node: unittest mock<3>,  Next: urllib<2>,  Prev: unittest<8>,  Up: Improved Modules<9>

1.9.5.73 unittest.mock
......................

The *note Mock: a58. class has the following improvements:

   * The class constructor has a new 'unsafe' parameter, which causes
     mock objects to raise *note AttributeError: 34e. on attribute names
     starting with ‘"assert"’.  (Contributed by Kushal Das in
     bpo-21238(1).)

   * A new *note Mock.assert_not_called(): ec2. method to check if the
     mock object was called.  (Contributed by Kushal Das in
     bpo-21262(2).)

The *note MagicMock: ec3. class now supports *note __truediv__(): ec4,
*note __divmod__(): ec5. and *note __matmul__(): da7. operators.
(Contributed by Johannes Baiter in bpo-20968(3), and Håkan Lövdahl in
bpo-23581(4) and bpo-23568(5).)

It is no longer necessary to explicitly pass ‘create=True’ to the *note
patch(): ec6. function when patching builtin names.  (Contributed by
Kushal Das in bpo-17660(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21238

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21262

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20968

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23581

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23568

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17660


File: python.info,  Node: urllib<2>,  Next: wsgiref,  Prev: unittest mock<3>,  Up: Improved Modules<9>

1.9.5.74 urllib
...............

A new *note request.HTTPPasswordMgrWithPriorAuth: ec8. class allows HTTP
Basic Authentication credentials to be managed so as to eliminate
unnecessary ‘401’ response handling, or to unconditionally send
credentials on the first request in order to communicate with servers
that return a ‘404’ response instead of a ‘401’ if the ‘Authorization’
header is not sent.  (Contributed by Matej Cepl in bpo-19494(1) and
Akshit Khurana in bpo-7159(2).)

A new 'quote_via' argument for the *note parse.urlencode(): ec9.
function provides a way to control the encoding of query parts if
needed.  (Contributed by Samwyse and Arnon Yaari in bpo-13866(3).)

The *note request.urlopen(): 293. function accepts an *note
ssl.SSLContext: 294. object as a 'context' argument, which will be used
for the HTTPS connection.  (Contributed by Alex Gaynor in bpo-22366(4).)

The *note parse.urljoin(): eca. was updated to use the RFC 3986(5)
semantics for the resolution of relative URLs, rather than RFC 1808(6)
and RFC 2396(7).  (Contributed by Demian Brecht and Senthil Kumaran in
bpo-22118(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19494

   (2) https://bugs.python.org/issue?@action=redirect&bpo=7159

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13866

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22366

   (5) https://datatracker.ietf.org/doc/html/rfc3986.html

   (6) https://datatracker.ietf.org/doc/html/rfc1808.html

   (7) https://datatracker.ietf.org/doc/html/rfc2396.html

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22118


File: python.info,  Node: wsgiref,  Next: xmlrpc<2>,  Prev: urllib<2>,  Up: Improved Modules<9>

1.9.5.75 wsgiref
................

The 'headers' argument of the *note headers.Headers: ecc. class
constructor is now optional.  (Contributed by Pablo Torres Navarrete and
SilentGhost in bpo-5800(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5800


File: python.info,  Node: xmlrpc<2>,  Next: xml sax,  Prev: wsgiref,  Up: Improved Modules<9>

1.9.5.76 xmlrpc
...............

The *note client.ServerProxy: a65. class now supports the *note context
manager: 5d7. protocol.  (Contributed by Claudiu Popa in bpo-20627(1).)

The *note client.ServerProxy: a65. constructor now accepts an optional
*note ssl.SSLContext: 294. instance.  (Contributed by Alex Gaynor in
bpo-22960(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20627

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22960


File: python.info,  Node: xml sax,  Next: zipfile<4>,  Prev: xmlrpc<2>,  Up: Improved Modules<9>

1.9.5.77 xml.sax
................

SAX parsers now support a character stream of the *note
xmlreader.InputSource: ecf. object.  (Contributed by Serhiy Storchaka in
bpo-2175(1).)

*note parseString(): ed0. now accepts a *note str: 44f. instance.
(Contributed by Serhiy Storchaka in bpo-10590(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2175

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10590


File: python.info,  Node: zipfile<4>,  Prev: xml sax,  Up: Improved Modules<9>

1.9.5.78 zipfile
................

ZIP output can now be written to unseekable streams.  (Contributed by
Serhiy Storchaka in bpo-23252(1).)

The 'mode' argument of *note ZipFile.open(): 41e. method now accepts
‘"x"’ to request exclusive creation.  (Contributed by Serhiy Storchaka
in bpo-21717(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23252

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21717


File: python.info,  Node: Other module-level changes,  Next: Optimizations<9>,  Prev: Improved Modules<9>,  Up: What’s New In Python 3 5

1.9.6 Other module-level changes
--------------------------------

Many functions in the *note mmap: 90, ‘ossaudiodev’, *note socket: cc,
*note ssl: d0, and *note codecs: 1b. modules now accept writable *note
bytes-like objects: d55.  (Contributed by Serhiy Storchaka in
bpo-23001(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23001


File: python.info,  Node: Optimizations<9>,  Next: Build and C API Changes<3>,  Prev: Other module-level changes,  Up: What’s New In Python 3 5

1.9.7 Optimizations
-------------------

The *note os.walk(): 4ac. function has been sped up by 3 to 5 times on
POSIX systems, and by 7 to 20 times on Windows.  This was done using the
new *note os.scandir(): a6d. function, which exposes file information
from the underlying ‘readdir’ or ‘FindFirstFile’/‘FindNextFile’ system
calls.  (Contributed by Ben Hoyt with help from Victor Stinner in
bpo-23605(1).)

Construction of ‘bytes(int)’ (filled by zero bytes) is faster and uses
less memory for large objects.  ‘calloc()’ is used instead of ‘malloc()’
to allocate memory for these objects.  (Contributed by Victor Stinner in
bpo-21233(2).)

Some operations on *note ipaddress: 80. *note IPv4Network: 1fe. and
*note IPv6Network: 1ff. have been massively sped up, such as *note
subnets(): ed4, *note supernet(): ed5, *note summarize_address_range():
ed6, *note collapse_addresses(): ed7.  The speed up can range from 3 to
15 times.  (Contributed by Antoine Pitrou, Michel Albert, and Markus in
bpo-21486(3), bpo-21487(4), bpo-20826(5), bpo-23266(6).)

Pickling of *note ipaddress: 80. objects was optimized to produce
significantly smaller output.  (Contributed by Serhiy Storchaka in
bpo-23133(7).)

Many operations on *note io.BytesIO: ed8. are now 50% to 100% faster.
(Contributed by Serhiy Storchaka in bpo-15381(8) and David Wilson in
bpo-22003(9).)

The *note marshal.dumps(): ed9. function is now faster: 65–85% with
versions 3 and 4, 20–25% with versions 0 to 2 on typical data, and up to
5 times in best cases.  (Contributed by Serhiy Storchaka in
bpo-20416(10) and bpo-23344(11).)

The UTF-32 encoder is now 3 to 7 times faster.  (Contributed by Serhiy
Storchaka in bpo-15027(12).)

Regular expressions are now parsed up to 10% faster.  (Contributed by
Serhiy Storchaka in bpo-19380(13).)

The *note json.dumps(): d6e. function was optimized to run with
‘ensure_ascii=False’ as fast as with ‘ensure_ascii=True’.  (Contributed
by Naoki Inada in bpo-23206(14).)

The *note PyObject_IsInstance(): eda. and *note PyObject_IsSubclass():
edb. functions have been sped up in the common case that the second
argument has *note type: d71. as its metaclass.  (Contributed Georg
Brandl by in bpo-22540(15).)

Method caching was slightly improved, yielding up to 5% performance
improvement in some benchmarks.  (Contributed by Antoine Pitrou in
bpo-22847(16).)

Objects from the *note random: b8. module now use 50% less memory on
64-bit builds.  (Contributed by Serhiy Storchaka in bpo-23488(17).)

The *note property(): 194. getter calls are up to 25% faster.
(Contributed by Joe Jevnik in bpo-23910(18).)

Instantiation of *note fractions.Fraction: 1e7. is now up to 30% faster.
(Contributed by Stefan Behnel in bpo-22464(19).)

String methods *note find(): edc, *note rfind(): edd, *note split():
ede, *note partition(): edf. and the *note in: 2f4. string operator are
now significantly faster for searching 1-character substrings.
(Contributed by Serhiy Storchaka in bpo-23573(20).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23605

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21233

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21486

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21487

   (5) https://bugs.python.org/issue?@action=redirect&bpo=20826

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23266

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23133

   (8) https://bugs.python.org/issue?@action=redirect&bpo=15381

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22003

   (10) https://bugs.python.org/issue?@action=redirect&bpo=20416

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23344

   (12) https://bugs.python.org/issue?@action=redirect&bpo=15027

   (13) https://bugs.python.org/issue?@action=redirect&bpo=19380

   (14) https://bugs.python.org/issue?@action=redirect&bpo=23206

   (15) https://bugs.python.org/issue?@action=redirect&bpo=22540

   (16) https://bugs.python.org/issue?@action=redirect&bpo=22847

   (17) https://bugs.python.org/issue?@action=redirect&bpo=23488

   (18) https://bugs.python.org/issue?@action=redirect&bpo=23910

   (19) https://bugs.python.org/issue?@action=redirect&bpo=22464

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23573


File: python.info,  Node: Build and C API Changes<3>,  Next: Deprecated<10>,  Prev: Optimizations<9>,  Up: What’s New In Python 3 5

1.9.8 Build and C API Changes
-----------------------------

New ‘calloc’ functions were added:

   * *note PyMem_RawCalloc(): 394,

   * *note PyMem_Calloc(): ee1,

   * *note PyObject_Calloc(): ee2.

(Contributed by Victor Stinner in bpo-21233(1).)

New encoding/decoding helper functions:

   * *note Py_DecodeLocale(): be6. (replaced ‘_Py_char2wchar()’),

   * *note Py_EncodeLocale(): be7. (replaced ‘_Py_wchar2char()’).

(Contributed by Victor Stinner in bpo-18395(2).)

A new *note PyCodec_NameReplaceErrors(): ee3. function to replace the
unicode encode error with ‘\N{...}’ escapes.  (Contributed by Serhiy
Storchaka in bpo-19676(3).)

A new *note PyErr_FormatV(): ee4. function similar to *note
PyErr_Format(): ee5, but accepts a ‘va_list’ argument.  (Contributed by
Antoine Pitrou in bpo-18711(4).)

A new *note PyExc_RecursionError: ee6. exception.  (Contributed by Georg
Brandl in bpo-19235(5).)

New *note PyModule_FromDefAndSpec(): ee7, *note
PyModule_FromDefAndSpec2(): ee8, and *note PyModule_ExecDef(): ee9.
functions introduced by PEP 489(6) – multi-phase extension module
initialization.  (Contributed by Petr Viktorin in bpo-24268(7).)

New *note PyNumber_MatrixMultiply(): eea. and *note
PyNumber_InPlaceMatrixMultiply(): eeb. functions to perform matrix
multiplication.  (Contributed by Benjamin Peterson in bpo-21176(8).  See
also PEP 465(9) for details.)

The *note PyTypeObject.tp_finalize: abb. slot is now part of the stable
ABI.

Windows builds now require Microsoft Visual C++ 14.0, which is available
as part of Visual Studio 2015(10).

Extension modules now include a platform information tag in their
filename on some platforms (the tag is optional, and CPython will import
extensions without it, although if the tag is present and mismatched,
the extension won’t be loaded):

   * On Linux, extension module filenames end with
     ‘.cpython-<major><minor>m-<architecture>-<os>.pyd’:

        * ‘<major>’ is the major number of the Python version; for
          Python 3.5 this is ‘3’.

        * ‘<minor>’ is the minor number of the Python version; for
          Python 3.5 this is ‘5’.

        * ‘<architecture>’ is the hardware architecture the extension
          module was built to run on.  It’s most commonly either ‘i386’
          for 32-bit Intel platforms or ‘x86_64’ for 64-bit Intel (and
          AMD) platforms.

        * ‘<os>’ is always ‘linux-gnu’, except for extensions built to
          talk to the 32-bit ABI on 64-bit platforms, in which case it
          is ‘linux-gnu32’ (and ‘<architecture>’ will be ‘x86_64’).

   * On Windows, extension module filenames end with
     ‘<debug>.cp<major><minor>-<platform>.pyd’:

        * ‘<major>’ is the major number of the Python version; for
          Python 3.5 this is ‘3’.

        * ‘<minor>’ is the minor number of the Python version; for
          Python 3.5 this is ‘5’.

        * ‘<platform>’ is the platform the extension module was built
          for, either ‘win32’ for Win32, ‘win_amd64’ for Win64,
          ‘win_ia64’ for Windows Itanium 64, and ‘win_arm’ for Windows
          on ARM.

        * If built in debug mode, ‘<debug>’ will be ‘_d’, otherwise it
          will be blank.

   * On OS X platforms, extension module filenames now end with
     ‘-darwin.so’.

   * On all other platforms, extension module filenames are the same as
     they were with Python 3.4.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21233

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18395

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19676

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18711

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19235

   (6) https://peps.python.org/pep-0489/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24268

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21176

   (9) https://peps.python.org/pep-0465/

   (10) 
https://visualstudio.microsoft.com/en/vs/older-downloads/#visual-studio-2015-and-other-products


File: python.info,  Node: Deprecated<10>,  Next: Removed<10>,  Prev: Build and C API Changes<3>,  Up: What’s New In Python 3 5

1.9.9 Deprecated
----------------

* Menu:

* New Keywords: New Keywords<2>.
* Deprecated Python Behavior: Deprecated Python Behavior<2>.
* Unsupported Operating Systems::
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<3>.


File: python.info,  Node: New Keywords<2>,  Next: Deprecated Python Behavior<2>,  Up: Deprecated<10>

1.9.9.1 New Keywords
....................

‘async’ and ‘await’ are not recommended to be used as variable, class,
function or module names.  Introduced by PEP 492(1) in Python 3.5, they
will become proper keywords in Python 3.7.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/


File: python.info,  Node: Deprecated Python Behavior<2>,  Next: Unsupported Operating Systems,  Prev: New Keywords<2>,  Up: Deprecated<10>

1.9.9.2 Deprecated Python Behavior
..................................

Raising the *note StopIteration: c1b. exception inside a generator will
now generate a silent *note PendingDeprecationWarning: 8d1, which will
become a non-silent deprecation warning in Python 3.6 and will trigger a
*note RuntimeError: 195. in Python 3.7.  See *note PEP 479; Change
StopIteration handling inside generators: d47. for details.


File: python.info,  Node: Unsupported Operating Systems,  Next: Deprecated Python modules functions and methods<3>,  Prev: Deprecated Python Behavior<2>,  Up: Deprecated<10>

1.9.9.3 Unsupported Operating Systems
.....................................

Windows XP is no longer supported by Microsoft, thus, per PEP 11(1),
CPython 3.5 is no longer officially supported on this OS.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0011/


File: python.info,  Node: Deprecated Python modules functions and methods<3>,  Prev: Unsupported Operating Systems,  Up: Deprecated<10>

1.9.9.4 Deprecated Python modules, functions and methods
........................................................

The ‘formatter’ module has now graduated to full deprecation and is
still slated for removal in Python 3.6.

The ‘asyncio.async()’ function is deprecated in favor of *note
ensure_future(): c98.

The ‘smtpd’ module has in the past always decoded the DATA portion of
email messages using the ‘utf-8’ codec.  This can now be controlled by
the new 'decode_data' keyword to ‘SMTPServer’.  The default value is
‘True’, but this default is deprecated.  Specify the 'decode_data'
keyword with an appropriate value to avoid the deprecation warning.

Directly assigning values to the *note key: c21, *note value: c22. and
*note coded_value: c23. of *note http.cookies.Morsel: c24. objects is
deprecated.  Use the *note set(): c25. method instead.  In addition, the
undocumented 'LegalChars' parameter of ‘set()’ is deprecated, and is now
ignored.

Passing a format string as keyword argument 'format_string' to the *note
format(): c20. method of the *note string.Formatter: ef1. class has been
deprecated.  (Contributed by Serhiy Storchaka in bpo-23671(1).)

The ‘platform.dist()’ and ‘platform.linux_distribution()’ functions are
now deprecated.  Linux distributions use too many different ways of
describing themselves, so the functionality is left to a package.
(Contributed by Vajrasky Kok and Berker Peksag in bpo-1322(2).)

The previously undocumented ‘from_function’ and ‘from_builtin’ methods
of *note inspect.Signature: 1cf. are deprecated.  Use the new *note
Signature.from_callable(): 73d. method instead.  (Contributed by Yury
Selivanov in bpo-24248(3).)

The ‘inspect.getargspec()’ function is deprecated and scheduled to be
removed in Python 3.6.  (See bpo-20438(4) for details.)

The *note inspect: 7e. *note getfullargspec(): 73c, *note getcallargs():
ef2, and ‘formatargspec()’ functions are deprecated in favor of the
*note inspect.signature(): 73b. API. (Contributed by Yury Selivanov in
bpo-20438(5).)

*note getargvalues(): ef3. and *note formatargvalues(): ef4. functions
were inadvertently marked as deprecated with the release of Python
3.5.0.

Use of *note re.LOCALE: b88. flag with str patterns or *note re.ASCII:
62f. is now deprecated.  (Contributed by Serhiy Storchaka in
bpo-22407(6).)

Use of unrecognized special sequences consisting of ‘'\'’ and an ASCII
letter in regular expression patterns and replacement patterns now
raises a deprecation warning and will be forbidden in Python 3.6.
(Contributed by Serhiy Storchaka in bpo-23622(7).)

The undocumented and unofficial 'use_load_tests' default argument of the
*note unittest.TestLoader.loadTestsFromModule(): 28f. method now is
deprecated and ignored.  (Contributed by Robert Collins and Barry A.
Warsaw in bpo-16662(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23671

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1322

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24248

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20438

   (5) https://bugs.python.org/issue?@action=redirect&bpo=20438

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22407

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23622

   (8) https://bugs.python.org/issue?@action=redirect&bpo=16662


File: python.info,  Node: Removed<10>,  Next: Porting to Python 3 5,  Prev: Deprecated<10>,  Up: What’s New In Python 3 5

1.9.10 Removed
--------------

* Menu:

* API and Feature Removals: API and Feature Removals<4>.


File: python.info,  Node: API and Feature Removals<4>,  Up: Removed<10>

1.9.10.1 API and Feature Removals
.................................

The following obsolete and previously deprecated APIs and features have
been removed:

   * The ‘__version__’ attribute has been dropped from the email
     package.  The email code hasn’t been shipped separately from the
     stdlib for a long time, and the ‘__version__’ string was not
     updated in the last few releases.

   * The internal ‘Netrc’ class in the *note ftplib: 5e. module was
     deprecated in 3.4, and has now been removed.  (Contributed by Matt
     Chaput in bpo-6623(1).)

   * The concept of ‘.pyo’ files has been removed.

   * The JoinableQueue class in the provisional *note asyncio: a. module
     was deprecated in 3.4.4 and is now removed.  (Contributed by A.
     Jesse Jiryu Davis in bpo-23464(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6623

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23464


File: python.info,  Node: Porting to Python 3 5,  Next: Notable changes in Python 3 5 4,  Prev: Removed<10>,  Up: What’s New In Python 3 5

1.9.11 Porting to Python 3.5
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in Python behavior: Changes in Python behavior<2>.
* Changes in the Python API: Changes in the Python API<9>.
* Changes in the C API: Changes in the C API<7>.


File: python.info,  Node: Changes in Python behavior<2>,  Next: Changes in the Python API<9>,  Up: Porting to Python 3 5

1.9.11.1 Changes in Python behavior
...................................

   * Due to an oversight, earlier Python versions erroneously accepted
     the following syntax:

          f(1 for x in [1], *args)
          f(1 for x in [1], **kwargs)

     Python 3.5 now correctly raises a *note SyntaxError: 18d, as
     generator expressions must be put in parentheses if not a sole
     argument to a function.


File: python.info,  Node: Changes in the Python API<9>,  Next: Changes in the C API<7>,  Prev: Changes in Python behavior<2>,  Up: Porting to Python 3 5

1.9.11.2 Changes in the Python API
..................................

   * PEP 475(1): System calls are now retried when interrupted by a
     signal instead of raising *note InterruptedError: db6. if the
     Python signal handler does not raise an exception.

   * Before Python 3.5, a *note datetime.time: 1ce. object was
     considered to be false if it represented midnight in UTC. This
     behavior was considered obscure and error-prone and has been
     removed in Python 3.5.  See bpo-13936(2) for full details.

   * The ‘ssl.SSLSocket.send()’ method now raises either *note
     ssl.SSLWantReadError: e9d. or *note ssl.SSLWantWriteError: e9e. on
     a non-blocking socket if the operation would block.  Previously, it
     would return ‘0’.  (Contributed by Nikolaus Rath in bpo-20951(3).)

   * The ‘__name__’ attribute of generators is now set from the function
     name, instead of being set from the code name.  Use
     ‘gen.gi_code.co_name’ to retrieve the code name.  Generators also
     have a new ‘__qualname__’ attribute, the qualified name, which is
     now used for the representation of a generator (‘repr(gen)’).
     (Contributed by Victor Stinner in bpo-21205(4).)

   * The deprecated “strict” mode and argument of *note HTMLParser: 87e,
     ‘HTMLParser.error()’, and the ‘HTMLParserError’ exception have been
     removed.  (Contributed by Ezio Melotti in bpo-15114(5).)  The
     'convert_charrefs' argument of ‘HTMLParser’ is now ‘True’ by
     default.  (Contributed by Berker Peksag in bpo-21047(6).)

   * Although it is not formally part of the API, it is worth noting for
     porting purposes (ie: fixing tests) that error messages that were
     previously of the form “‘sometype’ does not support the buffer
     protocol” are now of the form “a *note bytes-like object: d55. is
     required, not ‘sometype’”.  (Contributed by Ezio Melotti in
     bpo-16518(7).)

   * If the current directory is set to a directory that no longer
     exists then *note FileNotFoundError: 42e. will no longer be raised
     and instead *note find_spec(): efa. will return ‘None’ 'without'
     caching ‘None’ in *note sys.path_importer_cache: 5e7, which is
     different than the typical case (bpo-22834(8)).

   * HTTP status code and messages from *note http.client: 6f. and *note
     http.server: 72. were refactored into a common *note HTTPStatus:
     909. enum.  The values in ‘http.client’ and ‘http.server’ remain
     available for backwards compatibility.  (Contributed by Demian
     Brecht in bpo-21793(9).)

   * When an import loader defines *note exec_module(): 871. it is now
     expected to also define *note create_module(): cd4. (raises a *note
     DeprecationWarning: 1a5. now, will be an error in Python 3.6).  If
     the loader inherits from *note importlib.abc.Loader: efb. then
     there is nothing to do, else simply define ‘create_module()’ to
     return ‘None’.  (Contributed by Brett Cannon in bpo-23014(10).)

   * The *note re.split(): 2a2. function always ignored empty pattern
     matches, so the ‘"x*"’ pattern worked the same as ‘"x+"’, and the
     ‘"\b"’ pattern never worked.  Now ‘re.split()’ raises a warning if
     the pattern could match an empty string.  For compatibility, use
     patterns that never match an empty string (e.g.  ‘"x+"’ instead of
     ‘"x*"’).  Patterns that could only match an empty string (such as
     ‘"\b"’) now raise an error.  (Contributed by Serhiy Storchaka in
     bpo-22818(11).)

   * The *note http.cookies.Morsel: c24. dict-like interface has been
     made self consistent: morsel comparison now takes the *note key:
     c21. and *note value: c22. into account, *note copy(): efc. now
     results in a ‘Morsel’ instance rather than a *note dict: 256, and
     *note update(): efd. will now raise an exception if any of the keys
     in the update dictionary are invalid.  In addition, the
     undocumented 'LegalChars' parameter of *note set(): c25. is
     deprecated and is now ignored.  (Contributed by Demian Brecht in
     bpo-2211(12).)

   * PEP 488(13) has removed ‘.pyo’ files from Python and introduced the
     optional ‘opt-’ tag in ‘.pyc’ file names.  The *note
     importlib.util.cache_from_source(): 2fe. has gained an
     'optimization' parameter to help control the ‘opt-’ tag.  Because
     of this, the 'debug_override' parameter of the function is now
     deprecated.  ‘.pyo’ files are also no longer supported as a file
     argument to the Python interpreter and thus serve no purpose when
     distributed on their own (i.e.  sourceless code distribution).  Due
     to the fact that the magic number for bytecode has changed in
     Python 3.5, all old ‘.pyo’ files from previous versions of Python
     are invalid regardless of this PEP.

   * The *note socket: cc. module now exports the *note
     CAN_RAW_FD_FRAMES: efe. constant on linux 3.6 and greater.

   * The *note ssl.cert_time_to_seconds(): e9f. function now interprets
     the input time as UTC and not as local time, per RFC 5280(14).
     Additionally, the return value is always an *note int: 257.
     (Contributed by Akira Li in bpo-19940(15).)

   * The ‘pygettext.py’ Tool now uses the standard +NNNN format for
     timezones in the POT-Creation-Date header.

   * The *note smtplib: ca. module now uses *note sys.stderr: 943.
     instead of the previous module-level ‘stderr’ variable for debug
     output.  If your (test) program depends on patching the
     module-level variable to capture the debug output, you will need to
     update it to capture sys.stderr instead.

   * The *note str.startswith(): eff. and *note str.endswith(): f00.
     methods no longer return ‘True’ when finding the empty string and
     the indexes are completely out of range.  (Contributed by Serhiy
     Storchaka in bpo-24284(16).)

   * The *note inspect.getdoc(): a05. function now returns documentation
     strings inherited from base classes.  Documentation strings no
     longer need to be duplicated if the inherited documentation is
     appropriate.  To suppress an inherited string, an empty string must
     be specified (or the documentation may be filled in).  This change
     affects the output of the *note pydoc: b5. module and the *note
     help(): 8e0. function.  (Contributed by Serhiy Storchaka in
     bpo-15582(17).)

   * Nested *note functools.partial(): 417. calls are now flattened.  If
     you were relying on the previous behavior, you can now either add
     an attribute to a ‘functools.partial()’ object or you can create a
     subclass of ‘functools.partial()’.  (Contributed by Alexander
     Belopolsky in bpo-7830(18).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13936

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20951

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21205

   (5) https://bugs.python.org/issue?@action=redirect&bpo=15114

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21047

   (7) https://bugs.python.org/issue?@action=redirect&bpo=16518

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22834

   (9) https://bugs.python.org/issue?@action=redirect&bpo=21793

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23014

   (11) https://bugs.python.org/issue?@action=redirect&bpo=22818

   (12) https://bugs.python.org/issue?@action=redirect&bpo=2211

   (13) https://peps.python.org/pep-0488/

   (14) https://datatracker.ietf.org/doc/html/rfc5280.html

   (15) https://bugs.python.org/issue?@action=redirect&bpo=19940

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24284

   (17) https://bugs.python.org/issue?@action=redirect&bpo=15582

   (18) https://bugs.python.org/issue?@action=redirect&bpo=7830


File: python.info,  Node: Changes in the C API<7>,  Prev: Changes in the Python API<9>,  Up: Porting to Python 3 5

1.9.11.3 Changes in the C API
.............................

   * The undocumented ‘format’ member of the (non-public)
     ‘PyMemoryViewObject’ structure has been removed.  All extensions
     relying on the relevant parts in ‘memoryobject.h’ must be rebuilt.

   * The ‘PyMemAllocator’ structure was renamed to *note
     PyMemAllocatorEx: f02. and a new ‘calloc’ field was added.

   * Removed non-documented macro ‘PyObject_REPR()’ which leaked
     references.  Use format character ‘%R’ in *note
     PyUnicode_FromFormat(): 38d.-like functions to format the *note
     repr(): 803. of the object.  (Contributed by Serhiy Storchaka in
     bpo-22453(1).)

   * Because the lack of the *note __module__: 377. attribute breaks
     pickling and introspection, a deprecation warning is now raised for
     builtin types without the ‘__module__’ attribute.  This will be an
     *note AttributeError: 34e. in the future.  (Contributed by Serhiy
     Storchaka in bpo-20204(2).)

   * As part of the PEP 492(3) implementation, the ‘tp_reserved’ slot of
     *note PyTypeObject: aba. was replaced with a *note tp_as_async:
     f03. slot.  Refer to *note Coroutine Objects: f04. for new types,
     structures and functions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22453

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20204

   (3) https://peps.python.org/pep-0492/


File: python.info,  Node: Notable changes in Python 3 5 4,  Prev: Porting to Python 3 5,  Up: What’s New In Python 3 5

1.9.12 Notable changes in Python 3.5.4
--------------------------------------

* Menu:

* New make regen-all build target: New make regen-all build target<2>.
* Removal of make touch build target: Removal of make touch build target<2>.


File: python.info,  Node: New make regen-all build target<2>,  Next: Removal of make touch build target<2>,  Up: Notable changes in Python 3 5 4

1.9.12.1 New ‘make regen-all’ build target
..........................................

To simplify cross-compilation, and to ensure that CPython can reliably
be compiled without requiring an existing version of Python to already
be available, the autotools-based build system no longer attempts to
implicitly recompile generated files based on file modification times.

Instead, a new ‘make regen-all’ command has been added to force
regeneration of these files when desired (e.g.  after an initial version
of Python has already been built based on the pregenerated versions).

More selective regeneration targets are also defined - see
Makefile.pre.in(1) for details.

(Contributed by Victor Stinner in bpo-23404(2).)

Added in version 3.5.4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Makefile.pre.in

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: Removal of make touch build target<2>,  Prev: New make regen-all build target<2>,  Up: Notable changes in Python 3 5 4

1.9.12.2 Removal of ‘make touch’ build target
.............................................

The ‘make touch’ build target previously used to request implicit
regeneration of generated files by updating their modification times has
been removed.

It has been replaced by the new ‘make regen-all’ target.

(Contributed by Victor Stinner in bpo-23404(1).)

Changed in version 3.5.4.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: What’s New In Python 3 4,  Next: What’s New In Python 3 3,  Prev: What’s New In Python 3 5,  Up: What’s New in Python

1.10 What’s New In Python 3.4
=============================


Author: R. David Murray <<rdmurray@bitdance.com>> (Editor)

This article explains the new features in Python 3.4, compared to 3.3.
Python 3.4 was released on March 16, 2014.  For full details, see the
changelog(1).

See also
........

PEP 429(2) – Python 3.4 Release Schedule

* Menu:

* Summary – Release Highlights: Summary – Release Highlights<3>.
* New Features: New Features<15>.
* New Modules: New Modules<10>.
* Improved Modules: Improved Modules<10>.
* CPython Implementation Changes::
* Deprecated: Deprecated<11>.
* Removed: Removed<11>.
* Porting to Python 3.4: Porting to Python 3 4.
* Changed in 3.4.3: Changed in 3 4 3.

   ---------- Footnotes ----------

   (1) https://docs.python.org/3.4/whatsnew/changelog.html

   (2) https://peps.python.org/pep-0429/


File: python.info,  Node: Summary – Release Highlights<3>,  Next: New Features<15>,  Up: What’s New In Python 3 4

1.10.1 Summary – Release Highlights
-----------------------------------

New syntax features:

   * No new syntax features were added in Python 3.4.

Other new features:

   * *note pip should always be available: f0c. ( PEP 453(1)).

   * *note Newly created file descriptors are non-inheritable: f0d. (
     PEP 446(2)).

   * command line option for *note isolated mode: f0e. (bpo-16499(3)).

   * *note improvements in the handling of codecs: f0f. that are not
     text encodings (multiple issues).

   * *note A ModuleSpec Type: f10. for the Import System ( PEP 451(4)).
     (Affects importer authors.)

   * The *note marshal: 8d. format has been made *note more compact and
     efficient: f11. (bpo-16475(5)).

New library modules:

   * *note asyncio: a.: *note New provisional API for asynchronous IO:
     f12. ( PEP 3156(6)).

   * *note ensurepip: 55.: *note Bootstrapping the pip installer: f13. (
     PEP 453(7)).

   * *note enum: 56.: *note Support for enumeration types: f14. ( PEP
     435(8)).

   * *note pathlib: a4.: *note Object-oriented filesystem paths: f15. (
     PEP 428(9)).

   * *note selectors: c2.: *note High-level and efficient I/O
     multiplexing: f16, built upon the *note select: c1. module
     primitives (part of PEP 3156(10)).

   * *note statistics: d2.: A basic *note numerically stable statistics
     library: f17. ( PEP 450(11)).

   * *note tracemalloc: ff.: *note Trace Python memory allocations: f18.
     ( PEP 454(12)).

Significantly improved library modules:

   * *note Single-dispatch generic functions: f19. in *note functools:
     5f. ( PEP 443(13)).

   * New *note pickle: a6. *note protocol 4: f1a. ( PEP 3154(14)).

   * *note multiprocessing: 94. now has *note an option to avoid using
     os.fork on Unix: f1b. (bpo-8713(15)).

   * *note email: 3b. has a new submodule, *note contentmanager: 3d, and
     a new *note Message: 27c. subclass (*note EmailMessage: 27b.) that
     *note simplify MIME handling: f1c. (bpo-18891(16)).

   * The *note inspect: 7e. and *note pydoc: b5. modules are now capable
     of correct introspection of a much wider variety of callable
     objects, which improves the output of the Python *note help(): 8e0.
     system.

   * The *note ipaddress: 80. module API has been declared stable

Security improvements:

   * *note Secure and interchangeable hash algorithm: f1d. ( PEP
     456(17)).

   * *note Make newly created file descriptors non-inheritable: f0d. (
     PEP 446(18)) to avoid leaking file descriptors to child processes.

   * New command line option for *note isolated mode: f0e,
     (bpo-16499(19)).

   * *note multiprocessing: 94. now has *note an option to avoid using
     os.fork on Unix: f1b.  'spawn' and 'forkserver' are more secure
     because they avoid sharing data with child processes.

   * *note multiprocessing: 94. child processes on Windows no longer
     inherit all of the parent’s inheritable handles, only the necessary
     ones.

   * A new *note hashlib.pbkdf2_hmac(): 512. function provides the
     PKCS#5 password-based key derivation function 2(20).

   * *note TLSv1.1 and TLSv1.2 support: f1e. for *note ssl: d0.

   * *note Retrieving certificates from the Windows system cert store
     support: f1f. for *note ssl: d0.

   * *note Server-side SNI (Server Name Indication) support: f20. for
     *note ssl: d0.

   * The *note ssl.SSLContext: 294. class has a *note lot of
     improvements: f21.

   * All modules in the standard library that support SSL now support
     server certificate verification, including hostname matching
     (‘ssl.match_hostname()’) and CRLs (Certificate Revocation lists,
     see *note ssl.SSLContext.load_verify_locations(): f22.).

CPython implementation improvements:

   * *note Safe object finalization: f23. ( PEP 442(21)).

   * Leveraging PEP 442(22), in most cases *note module globals are no
     longer set to None during finalization: f23. (bpo-18214(23)).

   * *note Configurable memory allocators: f24. ( PEP 445(24)).

   * *note Argument Clinic: f25. ( PEP 436(25)).

Please read on for a comprehensive list of user-facing changes,
including many other smaller improvements, CPython optimizations,
deprecations, and potential porting issues.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0453/

   (2) https://peps.python.org/pep-0446/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16499

   (4) https://peps.python.org/pep-0451/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=16475

   (6) https://peps.python.org/pep-3156/

   (7) https://peps.python.org/pep-0453/

   (8) https://peps.python.org/pep-0435/

   (9) https://peps.python.org/pep-0428/

   (10) https://peps.python.org/pep-3156/

   (11) https://peps.python.org/pep-0450/

   (12) https://peps.python.org/pep-0454/

   (13) https://peps.python.org/pep-0443/

   (14) https://peps.python.org/pep-3154/

   (15) https://bugs.python.org/issue?@action=redirect&bpo=8713

   (16) https://bugs.python.org/issue?@action=redirect&bpo=18891

   (17) https://peps.python.org/pep-0456/

   (18) https://peps.python.org/pep-0446/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=16499

   (20) https://en.wikipedia.org/wiki/PBKDF2

   (21) https://peps.python.org/pep-0442/

   (22) https://peps.python.org/pep-0442/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=18214

   (24) https://peps.python.org/pep-0445/

   (25) https://peps.python.org/pep-0436/


File: python.info,  Node: New Features<15>,  Next: New Modules<10>,  Prev: Summary – Release Highlights<3>,  Up: What’s New In Python 3 4

1.10.2 New Features
-------------------

* Menu:

* PEP 453; Explicit Bootstrapping of PIP in Python Installations: PEP 453 Explicit Bootstrapping of PIP in Python Installations.
* PEP 446; Newly Created File Descriptors Are Non-Inheritable: PEP 446 Newly Created File Descriptors Are Non-Inheritable.
* Improvements to Codec Handling::
* PEP 451; A ModuleSpec Type for the Import System: PEP 451 A ModuleSpec Type for the Import System.
* Other Language Changes: Other Language Changes<10>.


File: python.info,  Node: PEP 453 Explicit Bootstrapping of PIP in Python Installations,  Next: PEP 446 Newly Created File Descriptors Are Non-Inheritable,  Up: New Features<15>

1.10.2.1 PEP 453: Explicit Bootstrapping of PIP in Python Installations
.......................................................................

* Menu:

* Bootstrapping pip By Default::
* Documentation Changes::


File: python.info,  Node: Bootstrapping pip By Default,  Next: Documentation Changes,  Up: PEP 453 Explicit Bootstrapping of PIP in Python Installations

1.10.2.2 Bootstrapping pip By Default
.....................................

The new *note ensurepip: 55. module (defined in PEP 453(1)) provides a
standard cross-platform mechanism to bootstrap the pip installer into
Python installations and virtual environments.  The version of ‘pip’
included with Python 3.4.0 is ‘pip’ 1.5.4, and future 3.4.x maintenance
releases will update the bundled version to the latest version of ‘pip’
that is available at the time of creating the release candidate.

By default, the commands ‘pipX’ and ‘pipX.Y’ will be installed on all
platforms (where X.Y stands for the version of the Python installation),
along with the ‘pip’ Python package and its dependencies.  On Windows
and in virtual environments on all platforms, the unversioned ‘pip’
command will also be installed.  On other platforms, the system wide
unversioned ‘pip’ command typically refers to the separately installed
Python 2 version.

The ‘pyvenv’ command line utility and the *note venv: 111. module make
use of the *note ensurepip: 55. module to make ‘pip’ readily available
in virtual environments.  When using the command line utility, ‘pip’ is
installed by default, while when using the ‘venv’ module *note API: f29.
installation of ‘pip’ must be requested explicitly.

For CPython *note source builds on POSIX systems: f2a, the ‘make
install’ and ‘make altinstall’ commands bootstrap ‘pip’ by default.
This behaviour can be controlled through configure options, and
overridden through Makefile options.

On Windows and Mac OS X, the CPython installers now default to
installing ‘pip’ along with CPython itself (users may opt out of
installing it during the installation process).  Window users will need
to opt in to the automatic ‘PATH’ modifications to have ‘pip’ available
from the command line by default, otherwise it can still be accessed
through the Python launcher for Windows as ‘py -m pip’.

As discussed in the PEP(2) platform packagers may choose not to install
these commands by default, as long as, when invoked, they provide clear
and simple directions on how to install them on that platform (usually
using the system package manager).

     Note: To avoid conflicts between parallel Python 2 and Python 3
     installations, only the versioned ‘pip3’ and ‘pip3.4’ commands are
     bootstrapped by default when ‘ensurepip’ is invoked directly - the
     ‘--default-pip’ option is needed to also request the unversioned
     ‘pip’ command.  ‘pyvenv’ and the Windows installer ensure that the
     unqualified ‘pip’ command is made available in those environments,
     and ‘pip’ can always be invoked via the ‘-m’ switch rather than
     directly to avoid ambiguity on systems with multiple Python
     installations.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0453/

   (2) 
https://peps.python.org/pep-0453/#recommendations-for-downstream-distributors


File: python.info,  Node: Documentation Changes,  Prev: Bootstrapping pip By Default,  Up: PEP 453 Explicit Bootstrapping of PIP in Python Installations

1.10.2.3 Documentation Changes
..............................

As part of this change, the *note Installing Python modules: f2c. and
distributing-index sections of the documentation have been completely
redesigned as short getting started and FAQ documents.  Most packaging
documentation has now been moved out to the Python Packaging Authority
maintained Python Packaging User Guide(1) and the documentation of the
individual projects.

However, as this migration is currently still incomplete, the legacy
versions of those guides remaining available as *note Building C and C++
Extensions with setuptools: f2d. and *note Building C and C++ Extensions
with setuptools: f2e.

See also
........

PEP 453(2) – Explicit bootstrapping of pip in Python installations

     PEP written by Donald Stufft and Nick Coghlan, implemented by
     Donald Stufft, Nick Coghlan, Martin von Löwis and Ned Deily.

   ---------- Footnotes ----------

   (1) https://packaging.python.org

   (2) https://peps.python.org/pep-0453/


File: python.info,  Node: PEP 446 Newly Created File Descriptors Are Non-Inheritable,  Next: Improvements to Codec Handling,  Prev: PEP 453 Explicit Bootstrapping of PIP in Python Installations,  Up: New Features<15>

1.10.2.4 PEP 446: Newly Created File Descriptors Are Non-Inheritable
....................................................................

PEP 446(1) makes newly created file descriptors *note non-inheritable:
f30.  In general, this is the behavior an application will want: when
launching a new process, having currently open files also open in the
new process can lead to all sorts of hard to find bugs, and potentially
to security issues.

However, there are occasions when inheritance is desired.  To support
these cases, the following new functions and methods are available:

   * *note os.get_inheritable(): f31, *note os.set_inheritable(): f32.

   * *note os.get_handle_inheritable(): f33, *note
     os.set_handle_inheritable(): f34.

   * *note socket.socket.get_inheritable(): f35, *note
     socket.socket.set_inheritable(): f36.

See also
........

PEP 446(2) – Make newly created file descriptors non-inheritable

     PEP written and implemented by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0446/

   (2) https://peps.python.org/pep-0446/


File: python.info,  Node: Improvements to Codec Handling,  Next: PEP 451 A ModuleSpec Type for the Import System,  Prev: PEP 446 Newly Created File Descriptors Are Non-Inheritable,  Up: New Features<15>

1.10.2.5 Improvements to Codec Handling
.......................................

Since it was first introduced, the *note codecs: 1b. module has always
been intended to operate as a type-neutral dynamic encoding and decoding
system.  However, its close coupling with the Python text model,
especially the type restricted convenience methods on the builtin *note
str: 44f, *note bytes: 1c2. and *note bytearray: 2ea. types, has
historically obscured that fact.

As a key step in clarifying the situation, the *note codecs.encode():
f38. and *note codecs.decode(): f39. convenience functions are now
properly documented in Python 2.7, 3.3 and 3.4.  These functions have
existed in the *note codecs: 1b. module (and have been covered by the
regression test suite) since Python 2.4, but were previously only
discoverable through runtime introspection.

Unlike the convenience methods on *note str: 44f, *note bytes: 1c2. and
*note bytearray: 2ea, the *note codecs: 1b. convenience functions
support arbitrary codecs in both Python 2 and Python 3, rather than
being limited to Unicode text encodings (in Python 3) or ‘basestring’
<-> ‘basestring’ conversions (in Python 2).

In Python 3.4, the interpreter is able to identify the known non-text
encodings provided in the standard library and direct users towards
these general purpose convenience functions when appropriate:

     >>> b"abcdef".decode("hex")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     LookupError: 'hex' is not a text encoding; use codecs.decode() to handle arbitrary codecs

     >>> "hello".encode("rot13")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     LookupError: 'rot13' is not a text encoding; use codecs.encode() to handle arbitrary codecs

     >>> open("foo.txt", encoding="hex")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     LookupError: 'hex' is not a text encoding; use codecs.open() to handle arbitrary codecs

In a related change, whenever it is feasible without breaking backwards
compatibility, exceptions raised during encoding and decoding operations
are wrapped in a chained exception of the same type that mentions the
name of the codec responsible for producing the error:

     >>> import codecs

     >>> codecs.decode(b"abcdefgh", "hex")
     Traceback (most recent call last):
       File "/usr/lib/python3.4/encodings/hex_codec.py", line 20, in hex_decode
         return (binascii.a2b_hex(input), len(input))
     binascii.Error: Non-hexadecimal digit found

     The above exception was the direct cause of the following exception:

     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     binascii.Error: decoding with 'hex' codec failed (Error: Non-hexadecimal digit found)

     >>> codecs.encode("hello", "bz2")
     Traceback (most recent call last):
       File "/usr/lib/python3.4/encodings/bz2_codec.py", line 17, in bz2_encode
         return (bz2.compress(input), len(input))
       File "/usr/lib/python3.4/bz2.py", line 498, in compress
         return comp.compress(data) + comp.flush()
     TypeError: 'str' does not support the buffer interface

     The above exception was the direct cause of the following exception:

     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: encoding with 'bz2' codec failed (TypeError: 'str' does not support the buffer interface)

Finally, as the examples above show, these improvements have permitted
the restoration of the convenience aliases for the non-Unicode codecs
that were themselves restored in Python 3.2.  This means that encoding
binary data to and from its hexadecimal representation (for example) can
now be written as:

     >>> from codecs import encode, decode
     >>> encode(b"hello", "hex")
     b'68656c6c6f'
     >>> decode(b"68656c6c6f", "hex")
     b'hello'

The binary and text transforms provided in the standard library are
detailed in *note Binary Transforms: f3a. and *note Text Transforms:
f3b.

(Contributed by Nick Coghlan in bpo-7475(1), bpo-17827(2), bpo-17828(3)
and bpo-19619(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7475

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17827

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17828

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19619


File: python.info,  Node: PEP 451 A ModuleSpec Type for the Import System,  Next: Other Language Changes<10>,  Prev: Improvements to Codec Handling,  Up: New Features<15>

1.10.2.6 PEP 451: A ModuleSpec Type for the Import System
.........................................................

PEP 451(1) provides an encapsulation of the information about a module
that the import machinery will use to load it (that is, a module
specification).  This helps simplify both the import implementation and
several import-related APIs.  The change is also a stepping stone for
several future import-related improvements(2).

The public-facing changes from the PEP are entirely backward-compatible.
Furthermore, they should be transparent to everyone but importer
authors.  Key finder and loader methods have been deprecated, but they
will continue working.  New importers should use the new methods
described in the PEP. Existing importers should be updated to implement
the new methods.  See the *note Deprecated: f3d. section for a list of
methods that should be replaced and their replacements.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0451/

   (2) 
https://mail.python.org/pipermail/python-dev/2013-November/130111.html


File: python.info,  Node: Other Language Changes<10>,  Prev: PEP 451 A ModuleSpec Type for the Import System,  Up: New Features<15>

1.10.2.7 Other Language Changes
...............................

Some smaller changes made to the core Python language are:

   * Unicode database updated to UCD version 6.3.

   * *note min(): f3f. and *note max(): f40. now accept a 'default'
     keyword-only argument that can be used to specify the value they
     return if the iterable they are evaluating has no elements.
     (Contributed by Julian Berman in bpo-18111(1).)

   * Module objects are now *note weakly referenceable: f41.

   * Module ‘__file__’ attributes (and related values) should now always
     contain absolute paths by default, with the sole exception of
     ‘__main__.__file__’ when a script has been executed directly using
     a relative path.  (Contributed by Brett Cannon in bpo-18416(2).)

   * All the UTF-* codecs (except UTF-7) now reject surrogates during
     both encoding and decoding unless the ‘surrogatepass’ error handler
     is used, with the exception of the UTF-16 decoder (which accepts
     valid surrogate pairs) and the UTF-16 encoder (which produces them
     while encoding non-BMP characters).  (Contributed by Victor
     Stinner, Kang-Hao (Kenny) Lu and Serhiy Storchaka in bpo-12892(3).)

   * New German EBCDIC *note codec: de7. ‘cp273’.  (Contributed by
     Michael Bierenfeld and Andrew Kuchling in bpo-1097797(4).)

   * New Ukrainian *note codec: de7. ‘cp1125’.  (Contributed by Serhiy
     Storchaka in bpo-19668(5).)

   * *note bytes: 1c2.join() and *note bytearray: 2ea.join() now accept
     arbitrary buffer objects as arguments.  (Contributed by Antoine
     Pitrou in bpo-15958(6).)

   * The *note int: 257. constructor now accepts any object that has an
     ‘__index__’ method for its 'base' argument.  (Contributed by Mark
     Dickinson in bpo-16772(7).)

   * Frame objects now have a *note clear(): 280. method that clears all
     references to local variables from the frame.  (Contributed by
     Antoine Pitrou in bpo-17934(8).)

   * *note memoryview: 2eb. is now registered as a *note Sequence: 1e,
     and supports the *note reversed(): 86c. builtin.  (Contributed by
     Nick Coghlan and Claudiu Popa in bpo-18690(9) and bpo-19078(10).)

   * Signatures reported by *note help(): 8e0. have been modified and
     improved in several cases as a result of the introduction of
     Argument Clinic and other changes to the *note inspect: 7e. and
     *note pydoc: b5. modules.

   * *note __length_hint__(): f42. is now part of the formal language
     specification (see PEP 424(11)).  (Contributed by Armin Ronacher in
     bpo-16148(12).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18111

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18416

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12892

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1097797

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19668

   (6) https://bugs.python.org/issue?@action=redirect&bpo=15958

   (7) https://bugs.python.org/issue?@action=redirect&bpo=16772

   (8) https://bugs.python.org/issue?@action=redirect&bpo=17934

   (9) https://bugs.python.org/issue?@action=redirect&bpo=18690

   (10) https://bugs.python.org/issue?@action=redirect&bpo=19078

   (11) https://peps.python.org/pep-0424/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=16148


File: python.info,  Node: New Modules<10>,  Next: Improved Modules<10>,  Prev: New Features<15>,  Up: What’s New In Python 3 4

1.10.3 New Modules
------------------

* Menu:

* asyncio: asyncio<11>.
* ensurepip: ensurepip<2>.
* enum: enum<9>.
* pathlib: pathlib<11>.
* selectors: selectors<2>.
* statistics: statistics<6>.
* tracemalloc: tracemalloc<4>.


File: python.info,  Node: asyncio<11>,  Next: ensurepip<2>,  Up: New Modules<10>

1.10.3.1 asyncio
................

The new *note asyncio: a. module (defined in PEP 3156(1)) provides a
standard pluggable event loop model for Python, providing solid
asynchronous IO support in the standard library, and making it easier
for other event loop implementations to interoperate with the standard
library and each other.

For Python 3.4, this module is considered a *note provisional API: b1c.

See also
........

PEP 3156(2) – Asynchronous IO Support Rebooted: the “asyncio” Module

     PEP written and implementation led by Guido van Rossum.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3156/

   (2) https://peps.python.org/pep-3156/


File: python.info,  Node: ensurepip<2>,  Next: enum<9>,  Prev: asyncio<11>,  Up: New Modules<10>

1.10.3.2 ensurepip
..................

The new *note ensurepip: 55. module is the primary infrastructure for
the PEP 453(1) implementation.  In the normal course of events end users
will not need to interact with this module, but it can be used to
manually bootstrap ‘pip’ if the automated bootstrapping into an
installation or virtual environment was declined.

*note ensurepip: 55. includes a bundled copy of ‘pip’, up-to-date as of
the first release candidate of the release of CPython with which it
ships (this applies to both maintenance releases and feature releases).
‘ensurepip’ does not access the internet.  If the installation has
internet access, after ‘ensurepip’ is run the bundled ‘pip’ can be used
to upgrade ‘pip’ to a more recent release than the bundled one.  (Note
that such an upgraded version of ‘pip’ is considered to be a separately
installed package and will not be removed if Python is uninstalled.)

The module is named 'ensure'pip because if called when ‘pip’ is already
installed, it does nothing.  It also has an ‘--upgrade’ option that will
cause it to install the bundled copy of ‘pip’ if the existing installed
version of ‘pip’ is older than the bundled copy.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0453/


File: python.info,  Node: enum<9>,  Next: pathlib<11>,  Prev: ensurepip<2>,  Up: New Modules<10>

1.10.3.3 enum
.............

The new *note enum: 56. module (defined in PEP 435(1)) provides a
standard implementation of enumeration types, allowing other modules
(such as *note socket: cc.) to provide more informative error messages
and better debugging support by replacing opaque integer constants with
backwards compatible enumeration values.

See also
........

PEP 435(2) – Adding an Enum type to the Python standard library

     PEP written by Barry Warsaw, Eli Bendersky and Ethan Furman,
     implemented by Ethan Furman.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0435/

   (2) https://peps.python.org/pep-0435/


File: python.info,  Node: pathlib<11>,  Next: selectors<2>,  Prev: enum<9>,  Up: New Modules<10>

1.10.3.4 pathlib
................

The new *note pathlib: a4. module offers classes representing filesystem
paths with semantics appropriate for different operating systems.  Path
classes are divided between 'pure paths', which provide purely
computational operations without I/O, and 'concrete paths', which
inherit from pure paths but also provide I/O operations.

For Python 3.4, this module is considered a *note provisional API: b1c.

See also
........

PEP 428(1) – The pathlib module – object-oriented filesystem paths

     PEP written and implemented by Antoine Pitrou.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0428/


File: python.info,  Node: selectors<2>,  Next: statistics<6>,  Prev: pathlib<11>,  Up: New Modules<10>

1.10.3.5 selectors
..................

The new *note selectors: c2. module (created as part of implementing PEP
3156(1)) allows high-level and efficient I/O multiplexing, built upon
the *note select: c1. module primitives.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3156/


File: python.info,  Node: statistics<6>,  Next: tracemalloc<4>,  Prev: selectors<2>,  Up: New Modules<10>

1.10.3.6 statistics
...................

The new *note statistics: d2. module (defined in PEP 450(1)) offers some
core statistics functionality directly in the standard library.  This
module supports calculation of the mean, median, mode, variance and
standard deviation of a data series.

See also
........

PEP 450(2) – Adding A Statistics Module To The Standard Library

     PEP written and implemented by Steven D’Aprano

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0450/

   (2) https://peps.python.org/pep-0450/


File: python.info,  Node: tracemalloc<4>,  Prev: statistics<6>,  Up: New Modules<10>

1.10.3.7 tracemalloc
....................

The new *note tracemalloc: ff. module (defined in PEP 454(1)) is a debug
tool to trace memory blocks allocated by Python.  It provides the
following information:

   * Trace where an object was allocated

   * Statistics on allocated memory blocks per filename and per line
     number: total size, number and average size of allocated memory
     blocks

   * Compute the differences between two snapshots to detect memory
     leaks

See also
........

PEP 454(2) – Add a new tracemalloc module to trace Python memory allocations

     PEP written and implemented by Victor Stinner

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0454/

   (2) https://peps.python.org/pep-0454/


File: python.info,  Node: Improved Modules<10>,  Next: CPython Implementation Changes,  Prev: New Modules<10>,  Up: What’s New In Python 3 4

1.10.4 Improved Modules
-----------------------

* Menu:

* abc::
* aifc: aifc<2>.
* argparse: argparse<5>.
* audioop::
* base64: base64<3>.
* collections: collections<6>.
* colorsys::
* contextlib: contextlib<6>.
* dbm: dbm<6>.
* dis: dis<4>.
* doctest: doctest<4>.
* email: email<4>.
* filecmp::
* functools: functools<5>.
* gc: gc<5>.
* glob: glob<4>.
* hashlib: hashlib<6>.
* hmac: hmac<3>.
* html::
* http: http<3>.
* idlelib and IDLE: idlelib and IDLE<4>.
* importlib: importlib<9>.
* inspect: inspect<8>.
* ipaddress: ipaddress<5>.
* logging: logging<6>.
* marshal: marshal<2>.
* mmap: mmap<3>.
* multiprocessing: multiprocessing<7>.
* operator: operator<3>.
* os: os<11>.
* pdb: pdb<6>.
* pickle: pickle<4>.
* plistlib: plistlib<2>.
* poplib: poplib<3>.
* pprint: pprint<4>.
* pty::
* pydoc: pydoc<4>.
* re: re<8>.
* resource::
* select::
* shelve: shelve<2>.
* shutil: shutil<6>.
* smtpd: smtpd<3>.
* smtplib: smtplib<3>.
* socket: socket<9>.
* sqlite3: sqlite3<9>.
* ssl: ssl<10>.
* stat::
* struct: struct<2>.
* subprocess: subprocess<5>.
* sunau: sunau<2>.
* sys: sys<12>.
* tarfile: tarfile<8>.
* textwrap::
* threading: threading<7>.
* traceback: traceback<6>.
* types: types<6>.
* urllib: urllib<3>.
* unittest: unittest<9>.
* venv: venv<7>.
* wave: wave<2>.
* weakref: weakref<2>.
* xml.etree: xml etree<2>.
* zipfile: zipfile<5>.


File: python.info,  Node: abc,  Next: aifc<2>,  Up: Improved Modules<10>

1.10.4.1 abc
............

New function *note abc.get_cache_token(): f4d. can be used to know when
to invalidate caches that are affected by changes in the object graph.
(Contributed by Łukasz Langa in bpo-16832(1).)

New class *note ABC: f4e. has *note ABCMeta: f4f. as its meta class.
Using ‘ABC’ as a base class has essentially the same effect as
specifying ‘metaclass=abc.ABCMeta’, but is simpler to type and easier to
read.  (Contributed by Bruno Dupuis in bpo-16049(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16832

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16049


File: python.info,  Node: aifc<2>,  Next: argparse<5>,  Prev: abc,  Up: Improved Modules<10>

1.10.4.2 aifc
.............

The ‘getparams()’ method now returns a namedtuple rather than a plain
tuple.  (Contributed by Claudiu Popa in bpo-17818(1).)

‘aifc.open()’ now supports the context management protocol: when used in
a *note with: 5d5. block, the ‘close()’ method of the returned object
will be called automatically at the end of the block.  (Contributed by
Serhiy Storchacha in bpo-16486(2).)

The ‘writeframesraw()’ and ‘writeframes()’ methods now accept any *note
bytes-like object: d55.  (Contributed by Serhiy Storchaka in
bpo-8311(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17818

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16486

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8311


File: python.info,  Node: argparse<5>,  Next: audioop,  Prev: aifc<2>,  Up: Improved Modules<10>

1.10.4.3 argparse
.................

The *note FileType: f52. class now accepts 'encoding' and 'errors'
arguments, which are passed through to *note open(): 51f.  (Contributed
by Lucas Maystre in bpo-11175(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11175


File: python.info,  Node: audioop,  Next: base64<3>,  Prev: argparse<5>,  Up: Improved Modules<10>

1.10.4.4 audioop
................

‘audioop’ now supports 24-bit samples.  (Contributed by Serhiy Storchaka
in bpo-12866(1).)

New ‘byteswap()’ function converts big-endian samples to little-endian
and vice versa.  (Contributed by Serhiy Storchaka in bpo-19641(2).)

All ‘audioop’ functions now accept any *note bytes-like object: d55.
Strings are not accepted: they didn’t work before, now they raise an
error right away.  (Contributed by Serhiy Storchaka in bpo-16685(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12866

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19641

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16685


File: python.info,  Node: base64<3>,  Next: collections<6>,  Prev: audioop,  Up: Improved Modules<10>

1.10.4.5 base64
...............

The encoding and decoding functions in *note base64: e. now accept any
*note bytes-like object: d55. in cases where it previously required a
*note bytes: 1c2. or *note bytearray: 2ea. instance.  (Contributed by
Nick Coghlan in bpo-17839(1).)

New functions *note a85encode(): f55, *note a85decode(): f56, *note
b85encode(): f57, and *note b85decode(): f58. provide the ability to
encode and decode binary data from and to ‘Ascii85’ and the
git/mercurial ‘Base85’ formats, respectively.  The ‘a85’ functions have
options that can be used to make them compatible with the variants of
the ‘Ascii85’ encoding, including the Adobe variant.  (Contributed by
Martin Morrison, the Mercurial project, Serhiy Storchaka, and Antoine
Pitrou in bpo-17618(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17839

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17618


File: python.info,  Node: collections<6>,  Next: colorsys,  Prev: base64<3>,  Up: Improved Modules<10>

1.10.4.6 collections
....................

The *note ChainMap.new_child(): f5a. method now accepts an 'm' argument
specifying the child map to add to the chain.  This allows an existing
mapping and/or a custom mapping type to be used for the child.
(Contributed by Vinay Sajip in bpo-16613(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16613


File: python.info,  Node: colorsys,  Next: contextlib<6>,  Prev: collections<6>,  Up: Improved Modules<10>

1.10.4.7 colorsys
.................

The number of digits in the coefficients for the RGB — YIQ conversions
have been expanded so that they match the FCC NTSC versions.  The change
in results should be less than 1% and may better match results found
elsewhere.  (Contributed by Brian Landers and Serhiy Storchaka in
bpo-14323(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14323


File: python.info,  Node: contextlib<6>,  Next: dbm<6>,  Prev: colorsys,  Up: Improved Modules<10>

1.10.4.8 contextlib
...................

The new *note contextlib.suppress: f5d. context manager helps to clarify
the intent of code that deliberately suppresses exceptions from a single
statement.  (Contributed by Raymond Hettinger in bpo-15806(1) and Zero
Piraeus in bpo-19266(2).)

The new *note contextlib.redirect_stdout(): e18. context manager makes
it easier for utility scripts to handle inflexible APIs that write their
output to *note sys.stdout: aec. and don’t provide any options to
redirect it.  Using the context manager, the ‘sys.stdout’ output can be
redirected to any other stream or, in conjunction with *note
io.StringIO: f5e, to a string.  The latter can be especially useful, for
example, to capture output from a function that was written to implement
a command line interface.  It is recommended only for utility scripts
because it affects the global state of ‘sys.stdout’.  (Contributed by
Raymond Hettinger in bpo-15805(3).)

The *note contextlib: 23. documentation has also been updated to include
a *note discussion: f5f. of the differences between single use, reusable
and reentrant context managers.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15806

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19266

   (3) https://bugs.python.org/issue?@action=redirect&bpo=15805


File: python.info,  Node: dbm<6>,  Next: dis<4>,  Prev: contextlib<6>,  Up: Improved Modules<10>

1.10.4.9 dbm
............

*note dbm.open(): f61. objects now support the context management
protocol.  When used in a *note with: 5d5. statement, the ‘close’ method
of the database object will be called automatically at the end of the
block.  (Contributed by Claudiu Popa and Nick Coghlan in bpo-19282(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19282


File: python.info,  Node: dis<4>,  Next: doctest<4>,  Prev: dbm<6>,  Up: Improved Modules<10>

1.10.4.10 dis
.............

Functions *note show_code(): f63, *note dis(): b4c, *note distb(): f64,
and *note disassemble(): f65. now accept a keyword-only 'file' argument
that controls where they write their output.

The *note dis: 38. module is now built around an *note Instruction: 1da.
class that provides object oriented access to the details of each
individual bytecode operation.

A new method, *note get_instructions(): 1d9, provides an iterator that
emits the Instruction stream for a given piece of Python code.  Thus it
is now possible to write a program that inspects and manipulates a
bytecode object in ways different from those provided by the *note dis:
38. module itself.  For example:

     >>> import dis
     >>> for instr in dis.get_instructions(lambda x: x + 1):
     ...     print(instr.opname)
     LOAD_FAST
     LOAD_CONST
     BINARY_ADD
     RETURN_VALUE

The various display tools in the *note dis: 38. module have been
rewritten to use these new components.

In addition, a new application-friendly class *note Bytecode: f66.
provides an object-oriented API for inspecting bytecode in both in
human-readable form and for iterating over instructions.  The ‘Bytecode’
constructor takes the same arguments that *note get_instructions(): 1d9.
does (plus an optional 'current_offset'), and the resulting object can
be iterated to produce *note Instruction: 1da. objects.  But it also has
a *note dis: f67. method, equivalent to calling *note dis: b4c. on the
constructor argument, but returned as a multi-line string:

     >>> bytecode = dis.Bytecode(lambda x: x + 1, current_offset=3)
     >>> for instr in bytecode:
     ...     print('{} ({})'.format(instr.opname, instr.opcode))
     LOAD_FAST (124)
     LOAD_CONST (100)
     BINARY_ADD (23)
     RETURN_VALUE (83)
     >>> bytecode.dis().splitlines()
     ['  1           0 LOAD_FAST                0 (x)',
      '      -->     3 LOAD_CONST               1 (1)',
      '              6 BINARY_ADD',
      '              7 RETURN_VALUE']

*note Bytecode: f66. also has a class method, *note from_traceback():
f68, that provides the ability to manipulate a traceback (that is,
‘print(Bytecode.from_traceback(tb).dis())’ is equivalent to
‘distb(tb)’).

(Contributed by Nick Coghlan, Ryan Kelly and Thomas Kluyver in
bpo-11816(1) and Claudiu Popa in bpo-17916(2).)

New function *note stack_effect(): f69. computes the effect on the
Python stack of a given opcode and argument, information that is not
otherwise available.  (Contributed by Larry Hastings in bpo-19722(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11816

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17916

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19722


File: python.info,  Node: doctest<4>,  Next: email<4>,  Prev: dis<4>,  Up: Improved Modules<10>

1.10.4.11 doctest
.................

A new *note option flag: f6b, *note FAIL_FAST: f6c, halts test running
as soon as the first failure is detected.  (Contributed by R. David
Murray and Daniel Urban in bpo-16522(1).)

The *note doctest: 3a. command line interface now uses *note argparse:
6, and has two new options, ‘-o’ and ‘-f’.  ‘-o’ allows *note doctest
options: f6b. to be specified on the command line, and ‘-f’ is a
shorthand for ‘-o FAIL_FAST’ (to parallel the similar option supported
by the *note unittest: 106. CLI). (Contributed by R. David Murray in
bpo-11390(2).)

*note doctest: 3a. will now find doctests in extension module ‘__doc__’
strings.  (Contributed by Zachary Ware in bpo-3158(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16522

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11390

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3158


File: python.info,  Node: email<4>,  Next: filecmp,  Prev: doctest<4>,  Up: Improved Modules<10>

1.10.4.12 email
...............

*note as_string(): f6e. now accepts a 'policy' argument to override the
default policy of the message when generating a string representation of
it.  This means that ‘as_string’ can now be used in more circumstances,
instead of having to create and use a *note generator: 40. in order to
pass formatting parameters to its ‘flatten’ method.  (Contributed by R.
David Murray in bpo-18600(1).)

New method *note as_bytes(): f6f. added to produce a bytes
representation of the message in a fashion similar to how ‘as_string’
produces a string representation.  It does not accept the 'maxheaderlen'
argument, but does accept the 'unixfrom' and 'policy' arguments.  The
*note Message: 27c. *note __bytes__(): f70. method calls it, meaning
that ‘bytes(mymsg)’ will now produce the intuitive result: a bytes
object containing the fully formatted message.  (Contributed by R. David
Murray in bpo-18600(2).)

The *note Message.set_param(): f71. message now accepts a 'replace'
keyword argument.  When specified, the associated header will be updated
without changing its location in the list of headers.  For backward
compatibility, the default is ‘False’.  (Contributed by R. David Murray
in bpo-18891(3).)  A pair of new subclasses of *note Message: 27c. have
been added (*note EmailMessage: 27b. and *note MIMEPart: f72.), along
with a new sub-module, *note contentmanager: 3d. and a new *note policy:
4f. attribute *note content_manager: f73.  All documentation is
currently in the new module, which is being added as part of email’s new
*note provisional API: b1c.  These classes provide a number of new
methods that make extracting content from and inserting content into
email messages much easier.  For details, see the ‘contentmanager’
documentation and the *note email; Examples: f74.  These API additions
complete the bulk of the work that was planned as part of the email6
project.  The currently provisional API is scheduled to become final in
Python 3.5 (possibly with a few minor additions in the area of error
handling).  (Contributed by R. David Murray in bpo-18891(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18600

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18600

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18891

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18891


File: python.info,  Node: filecmp,  Next: functools<5>,  Prev: email<4>,  Up: Improved Modules<10>

1.10.4.13 filecmp
.................

A new *note clear_cache(): f76. function provides the ability to clear
the *note filecmp: 5a. comparison cache, which uses *note os.stat():
4a3. information to determine if the file has changed since the last
compare.  This can be used, for example, if the file might have been
changed and re-checked in less time than the resolution of a particular
filesystem’s file modification time field.  (Contributed by Mark Levitt
in bpo-18149(1).)

New module attribute *note DEFAULT_IGNORES: f77. provides the list of
directories that are used as the default value for the 'ignore'
parameter of the *note dircmp(): f78. function.  (Contributed by Eli
Bendersky in bpo-15442(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18149

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15442


File: python.info,  Node: functools<5>,  Next: gc<5>,  Prev: filecmp,  Up: Improved Modules<10>

1.10.4.14 functools
...................

The new *note partialmethod(): a8a. descriptor brings partial argument
application to descriptors, just as *note partial(): 417. provides for
normal callables.  The new descriptor also makes it easier to get
arbitrary callables (including ‘partial()’ instances) to behave like
normal instance methods when included in a class definition.
(Contributed by Alon Horev and Nick Coghlan in bpo-4331(1).)  The new
*note singledispatch(): 63c. decorator brings support for
single-dispatch generic functions to the Python standard library.  Where
object oriented programming focuses on grouping multiple operations on a
common set of data into a class, a generic function focuses on grouping
multiple implementations of an operation that allows it to work with
'different' kinds of data.

See also
........

PEP 443(2) – Single-dispatch generic functions

     PEP written and implemented by Łukasz Langa.

*note total_ordering(): f7a. now supports a return value of *note
NotImplemented: 7d6. from the underlying comparison function.
(Contributed by Katie Miller in bpo-10042(3).)

A pure-python version of the *note partial(): 417. function is now in
the stdlib; in CPython it is overridden by the C accelerated version,
but it is available for other implementations to use.  (Contributed by
Brian Thorne in bpo-12428(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4331

   (2) https://peps.python.org/pep-0443/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=10042

   (4) https://bugs.python.org/issue?@action=redirect&bpo=12428


File: python.info,  Node: gc<5>,  Next: glob<4>,  Prev: functools<5>,  Up: Improved Modules<10>

1.10.4.15 gc
............

New function *note get_stats(): f7c. returns a list of three
per-generation dictionaries containing the collections statistics since
interpreter startup.  (Contributed by Antoine Pitrou in bpo-16351(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16351


File: python.info,  Node: glob<4>,  Next: hashlib<6>,  Prev: gc<5>,  Up: Improved Modules<10>

1.10.4.16 glob
..............

A new function *note escape(): f7e. provides a way to escape special
characters in a filename so that they do not become part of the globbing
expansion but are instead matched literally.  (Contributed by Serhiy
Storchaka in bpo-8402(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8402


File: python.info,  Node: hashlib<6>,  Next: hmac<3>,  Prev: glob<4>,  Up: Improved Modules<10>

1.10.4.17 hashlib
.................

A new *note hashlib.pbkdf2_hmac(): 512. function provides the PKCS#5
password-based key derivation function 2(1).  (Contributed by Christian
Heimes in bpo-18582(2).)

The *note name: f80. attribute of *note hashlib: 68. hash objects is now
a formally supported interface.  It has always existed in CPython’s
‘hashlib’ (although it did not return lower case names for all supported
hashes), but it was not a public interface and so some other Python
implementations have not previously supported it.  (Contributed by Jason
R. Coombs in bpo-18532(3).)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/PBKDF2

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18582

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18532


File: python.info,  Node: hmac<3>,  Next: html,  Prev: hashlib<6>,  Up: Improved Modules<10>

1.10.4.18 hmac
..............

*note hmac: 6a. now accepts ‘bytearray’ as well as ‘bytes’ for the 'key'
argument to the *note new(): ab4. function, and the 'msg' parameter to
both the ‘new()’ function and the *note update(): f82. method now
accepts any type supported by the *note hashlib: 68. module.
(Contributed by Jonas Borgström in bpo-18240(1).)

The 'digestmod' argument to the *note hmac.new(): ab4. function may now
be any hash digest name recognized by *note hashlib: 68.  In addition,
the current behavior in which the value of 'digestmod' defaults to ‘MD5’
is deprecated: in a future version of Python there will be no default
value.  (Contributed by Christian Heimes in bpo-17276(2).)

With the addition of *note block_size: f83. and *note name: f84.
attributes (and the formal documentation of the *note digest_size: f85.
attribute), the *note hmac: 6a. module now conforms fully to the PEP
247(3) API. (Contributed by Christian Heimes in bpo-18775(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18240

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17276

   (3) https://peps.python.org/pep-0247/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18775


File: python.info,  Node: html,  Next: http<3>,  Prev: hmac<3>,  Up: Improved Modules<10>

1.10.4.19 html
..............

New function *note unescape(): 961. function converts HTML5 character
references to the corresponding Unicode characters.  (Contributed by
Ezio Melotti in bpo-2927(1).)

*note HTMLParser: 87e. accepts a new keyword argument 'convert_charrefs'
that, when ‘True’, automatically converts all character references.  For
backward-compatibility, its value defaults to ‘False’, but it will
change to ‘True’ in a future version of Python, so you are invited to
set it explicitly and update your code to use this new feature.
(Contributed by Ezio Melotti in bpo-13633(2).)

The 'strict' argument of *note HTMLParser: 87e. is now deprecated.
(Contributed by Ezio Melotti in bpo-15114(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2927

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13633

   (3) https://bugs.python.org/issue?@action=redirect&bpo=15114


File: python.info,  Node: http<3>,  Next: idlelib and IDLE<4>,  Prev: html,  Up: Improved Modules<10>

1.10.4.20 http
..............

*note send_error(): f88. now accepts an optional additional 'explain'
parameter which can be used to provide an extended error description,
overriding the hardcoded default if there is one.  This extended error
description will be formatted using the *note error_message_format: f89.
attribute and sent as the body of the error response.  (Contributed by
Karl Cow in bpo-12921(1).)

The *note http.server: 72. *note command line interface: f8a. now has a
‘-b/--bind’ option that causes the server to listen on a specific
address.  (Contributed by Malte Swart in bpo-17764(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12921

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17764


File: python.info,  Node: idlelib and IDLE<4>,  Next: importlib<9>,  Prev: http<3>,  Up: Improved Modules<10>

1.10.4.21 idlelib and IDLE
..........................

Since idlelib implements the IDLE shell and editor and is not intended
for import by other programs, it gets improvements with every release.
See ‘Lib/idlelib/NEWS.txt’ for a cumulative list of changes since 3.3.0,
as well as changes made in future 3.4.x releases.  This file is also
available from the IDLE Help ‣ About IDLE dialog.


File: python.info,  Node: importlib<9>,  Next: inspect<8>,  Prev: idlelib and IDLE<4>,  Up: Improved Modules<10>

1.10.4.22 importlib
...................

The *note InspectLoader: f8d. ABC defines a new method, *note
source_to_code(): e43. that accepts source data and a path and returns a
code object.  The default implementation is equivalent to ‘compile(data,
path, 'exec', dont_inherit=True)’.  (Contributed by Eric Snow and Brett
Cannon in bpo-15627(1).)

*note InspectLoader: f8d. also now has a default implementation for the
*note get_code(): f8e. method.  However, it will normally be desirable
to override the default implementation for performance reasons.
(Contributed by Brett Cannon in bpo-18072(2).)

The *note reload(): 51c. function has been moved from ‘imp’ to *note
importlib: 77. as part of the ‘imp’ module deprecation.  (Contributed by
Berker Peksag in bpo-18193(3).)

*note importlib.util: 7d. now has a *note MAGIC_NUMBER: 516. attribute
providing access to the bytecode version number.  This replaces the
‘get_magic()’ function in the deprecated ‘imp’ module.  (Contributed by
Brett Cannon in bpo-18192(4).)

New *note importlib.util: 7d. functions *note cache_from_source(): 2fe.
and *note source_from_cache(): 51d. replace the same-named functions in
the deprecated ‘imp’ module.  (Contributed by Brett Cannon in
bpo-18194(5).)

The *note importlib: 77. bootstrap *note NamespaceLoader: f8f. now
conforms to the *note InspectLoader: f8d. ABC, which means that ‘runpy’
and ‘python -m’ can now be used with namespace packages.  (Contributed
by Brett Cannon in bpo-18058(6).)

*note importlib.util: 7d. has a new function *note decode_source(): f90.
that decodes source from bytes using universal newline processing.  This
is useful for implementing *note InspectLoader.get_source(): f91.
methods.

*note importlib.machinery.ExtensionFileLoader: cd6. now has a *note
get_filename(): f92. method.  This was inadvertently omitted in the
original implementation.  (Contributed by Eric Snow in bpo-19152(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15627

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18072

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18193

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18192

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18194

   (6) https://bugs.python.org/issue?@action=redirect&bpo=18058

   (7) https://bugs.python.org/issue?@action=redirect&bpo=19152


File: python.info,  Node: inspect<8>,  Next: ipaddress<5>,  Prev: importlib<9>,  Up: Improved Modules<10>

1.10.4.23 inspect
.................

The *note inspect: 7e. module now offers a basic *note command line
interface: f94. to quickly display source code and other information for
modules, classes and functions.  (Contributed by Claudiu Popa and Nick
Coghlan in bpo-18626(1).)

*note unwrap(): f95. makes it easy to unravel wrapper function chains
created by *note functools.wraps(): f96. (and any other API that sets
the ‘__wrapped__’ attribute on a wrapper function).  (Contributed by
Daniel Urban, Aaron Iles and Nick Coghlan in bpo-13266(2).)

As part of the implementation of the new *note enum: 56. module, the
*note inspect: 7e. module now has substantially better support for
custom ‘__dir__’ methods and dynamic class attributes provided through
metaclasses.  (Contributed by Ethan Furman in bpo-18929(3) and
bpo-19030(4).)

*note getfullargspec(): 73c. and ‘getargspec()’ now use the *note
signature(): 73b. API. This allows them to support a much broader range
of callables, including those with ‘__signature__’ attributes, those
with metadata provided by argument clinic, *note functools.partial():
417. objects and more.  Note that, unlike ‘signature()’, these functions
still ignore ‘__wrapped__’ attributes, and report the already bound
first argument for bound methods, so it is still necessary to update
your code to use ‘signature()’ directly if those features are desired.
(Contributed by Yury Selivanov in bpo-17481(5).)

*note signature(): 73b. now supports duck types of CPython functions,
which adds support for functions compiled with Cython.  (Contributed by
Stefan Behnel and Yury Selivanov in bpo-17159(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18626

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13266

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18929

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19030

   (5) https://bugs.python.org/issue?@action=redirect&bpo=17481

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17159


File: python.info,  Node: ipaddress<5>,  Next: logging<6>,  Prev: inspect<8>,  Up: Improved Modules<10>

1.10.4.24 ipaddress
...................

*note ipaddress: 80. was added to the standard library in Python 3.3 as
a *note provisional API: b1c.  With the release of Python 3.4, this
qualification has been removed: ‘ipaddress’ is now considered a stable
API, covered by the normal standard library requirements to maintain
backwards compatibility.

A new *note is_global: f98. property is ‘True’ if an address is globally
routeable.  (Contributed by Peter Moody in bpo-17400(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17400


File: python.info,  Node: logging<6>,  Next: marshal<2>,  Prev: ipaddress<5>,  Up: Improved Modules<10>

1.10.4.25 logging
.................

The *note TimedRotatingFileHandler: f9a. has a new 'atTime' parameter
that can be used to specify the time of day when rollover should happen.
(Contributed by Ronald Oussoren in bpo-9556(1).)

*note SocketHandler: f9b. and *note DatagramHandler: f9c. now support
Unix domain sockets (by setting 'port' to ‘None’).  (Contributed by
Vinay Sajip in commit ce46195b56a9.)

*note fileConfig(): b6c. now accepts a *note
configparser.RawConfigParser: f9d. subclass instance for the 'fname'
parameter.  This facilitates using a configuration file when logging
configuration is just a part of the overall application configuration,
or where the application modifies the configuration before passing it to
‘fileConfig()’.  (Contributed by Vinay Sajip in bpo-16110(2).)

Logging configuration data received from a socket via the *note
logging.config.listen(): f9e. function can now be validated before being
processed by supplying a verification function as the argument to the
new 'verify' keyword argument.  (Contributed by Vinay Sajip in
bpo-15452(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9556

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16110

   (3) https://bugs.python.org/issue?@action=redirect&bpo=15452


File: python.info,  Node: marshal<2>,  Next: mmap<3>,  Prev: logging<6>,  Up: Improved Modules<10>

1.10.4.26 marshal
.................

The default *note marshal: 8d. version has been bumped to 3.  The code
implementing the new version restores the Python2 behavior of recording
only one copy of interned strings and preserving the interning on
deserialization, and extends this “one copy” ability to any object type
(including handling recursive references).  This reduces both the size
of ‘.pyc’ files and the amount of memory a module occupies in memory
when it is loaded from a ‘.pyc’ (or ‘.pyo’) file.  (Contributed by
Kristján Valur Jónsson in bpo-16475(1), with additional speedups by
Antoine Pitrou in bpo-19219(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16475

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19219


File: python.info,  Node: mmap<3>,  Next: multiprocessing<7>,  Prev: marshal<2>,  Up: Improved Modules<10>

1.10.4.27 mmap
..............

mmap objects are now *note weakly referenceable: f41.  (Contributed by
Valerie Lambert in bpo-4885(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4885


File: python.info,  Node: multiprocessing<7>,  Next: operator<3>,  Prev: mmap<3>,  Up: Improved Modules<10>

1.10.4.28 multiprocessing
.........................

On Unix two new *note start methods: 2c8, ‘spawn’ and ‘forkserver’, have
been added for starting processes using *note multiprocessing: 94.
These make the mixing of processes with threads more robust, and the
‘spawn’ method matches the semantics that multiprocessing has always
used on Windows.  New function *note get_all_start_methods(): fa2.
reports all start methods available on the platform, *note
get_start_method(): fa3. reports the current start method, and *note
set_start_method(): 2c7. sets the start method.  (Contributed by Richard
Oudkerk in bpo-8713(1).)

*note multiprocessing: 94. also now has the concept of a ‘context’,
which determines how child processes are created.  New function *note
get_context(): 2c6. returns a context that uses a specified start
method.  It has the same API as the ‘multiprocessing’ module itself, so
you can use it to create *note Pool: fa4.s and other objects that will
operate within that context.  This allows a framework and an application
or different parts of the same application to use multiprocessing
without interfering with each other.  (Contributed by Richard Oudkerk in
bpo-18999(2).)

Except when using the old 'fork' start method, child processes no longer
inherit unneeded handles/file descriptors from their parents (part of
bpo-8713(3)).

*note multiprocessing: 94. now relies on *note runpy: be. (which
implements the ‘-m’ switch) to initialise ‘__main__’ appropriately in
child processes when using the ‘spawn’ or ‘forkserver’ start methods.
This resolves some edge cases where combining multiprocessing, the ‘-m’
command line switch, and explicit relative imports could cause obscure
failures in child processes.  (Contributed by Nick Coghlan in
bpo-19946(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8713

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18999

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8713

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19946


File: python.info,  Node: operator<3>,  Next: os<11>,  Prev: multiprocessing<7>,  Up: Improved Modules<10>

1.10.4.29 operator
..................

New function *note length_hint(): fa6. provides an implementation of the
specification for how the *note __length_hint__(): f42. special method
should be used, as part of the PEP 424(1) formal specification of this
language feature.  (Contributed by Armin Ronacher in bpo-16148(2).)

There is now a pure-python version of the *note operator: 9f. module
available for reference and for use by alternate implementations of
Python.  (Contributed by Zachary Ware in bpo-16694(3).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0424/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16148

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16694


File: python.info,  Node: os<11>,  Next: pdb<6>,  Prev: operator<3>,  Up: Improved Modules<10>

1.10.4.30 os
............

There are new functions to get and set the *note inheritable flag: f30.
of a file descriptor (*note os.get_inheritable(): f31, *note
os.set_inheritable(): f32.) or a Windows handle (*note
os.get_handle_inheritable(): f33, *note os.set_handle_inheritable():
f34.).

New function *note cpu_count(): 1c5. reports the number of CPUs
available on the platform on which Python is running (or ‘None’ if the
count can’t be determined).  The *note multiprocessing.cpu_count(): fa8.
function is now implemented in terms of this function).  (Contributed by
Trent Nelson, Yogesh Chaudhari, Victor Stinner, and Charles-François
Natali in bpo-17914(1).)

*note os.path.samestat(): fa9. is now available on the Windows platform
(and the *note os.path.samefile(): faa. implementation is now shared
between Unix and Windows).  (Contributed by Brian Curtin in
bpo-11939(2).)

*note os.path.ismount(): a1f. now recognizes volumes mounted below a
drive root on Windows.  (Contributed by Tim Golden in bpo-9035(3).)

*note os.open(): dc0. supports two new flags on platforms that provide
them, *note O_PATH: fab. (un-opened file descriptor), and *note
O_TMPFILE: fac. (unnamed temporary file; as of 3.4.0 release available
only on Linux systems with a kernel version of 3.11 or newer that have
uapi headers).  (Contributed by Christian Heimes in bpo-18673(4) and
Benjamin Peterson, respectively.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17914

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11939

   (3) https://bugs.python.org/issue?@action=redirect&bpo=9035

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18673


File: python.info,  Node: pdb<6>,  Next: pickle<4>,  Prev: os<11>,  Up: Improved Modules<10>

1.10.4.31 pdb
.............

*note pdb: a5. has been enhanced to handle generators, *note yield: 9d8,
and ‘yield from’ in a more useful fashion.  This is especially helpful
when debugging *note asyncio: a. based programs.  (Contributed by Andrew
Svetlov and Xavier de Gaye in bpo-16596(1).)

The ‘print’ command has been removed from *note pdb: a5, restoring
access to the Python *note print(): fae. function from the pdb command
line.  Python2’s ‘pdb’ did not have a ‘print’ command; instead, entering
‘print’ executed the ‘print’ statement.  In Python3 ‘print’ was
mistakenly made an alias for the pdb *note p: faf. command.  ‘p’,
however, prints the ‘repr’ of its argument, not the ‘str’ like the
Python2 ‘print’ command did.  Worse, the Python3 ‘pdb print’ command
shadowed the Python3 ‘print’ function, making it inaccessible at the
‘pdb’ prompt.  (Contributed by Connor Osborn in bpo-18764(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16596

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18764


File: python.info,  Node: pickle<4>,  Next: plistlib<2>,  Prev: pdb<6>,  Up: Improved Modules<10>

1.10.4.32 pickle
................

*note pickle: a6. now supports (but does not use by default) a new
pickle protocol, protocol 4.  This new protocol addresses a number of
issues that were present in previous protocols, such as the
serialization of nested classes, very large strings and containers, and
classes whose *note __new__(): 583. method takes keyword-only arguments.
It also provides some efficiency improvements.

See also
........

PEP 3154(1) – Pickle protocol 4

     PEP written by Antoine Pitrou and implemented by Alexandre
     Vassalotti.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3154/


File: python.info,  Node: plistlib<2>,  Next: poplib<3>,  Prev: pickle<4>,  Up: Improved Modules<10>

1.10.4.33 plistlib
..................

*note plistlib: ab. now has an API that is similar to the standard
pattern for stdlib serialization protocols, with new *note load(): 959,
*note dump(): 95b, *note loads(): 95a, and *note dumps(): 95c.
functions.  (The older API is now deprecated.)  In addition to the
already supported XML plist format (*note FMT_XML: fb2.), it also now
supports the binary plist format (*note FMT_BINARY: fb3.).  (Contributed
by Ronald Oussoren and others in bpo-14455(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14455


File: python.info,  Node: poplib<3>,  Next: pprint<4>,  Prev: plistlib<2>,  Up: Improved Modules<10>

1.10.4.34 poplib
................

Two new methods have been added to *note poplib: ac.: *note capa(): fb5,
which returns the list of capabilities advertised by the POP server, and
*note stls(): fb6, which switches a clear-text POP3 session into an
encrypted POP3 session if the POP server supports it.  (Contributed by
Lorenzo Catucci in bpo-4473(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4473


File: python.info,  Node: pprint<4>,  Next: pty,  Prev: poplib<3>,  Up: Improved Modules<10>

1.10.4.35 pprint
................

The *note pprint: ae. module’s *note PrettyPrinter: fb8. class and its
*note pformat(): fb9, and *note pprint(): 82e. functions have a new
option, 'compact', that controls how the output is formatted.  Currently
setting 'compact' to ‘True’ means that sequences will be printed with as
many sequence elements as will fit within 'width' on each (indented)
line.  (Contributed by Serhiy Storchaka in bpo-19132(1).)

Long strings are now wrapped using Python’s normal line continuation
syntax.  (Contributed by Antoine Pitrou in bpo-17150(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19132

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17150


File: python.info,  Node: pty,  Next: pydoc<4>,  Prev: pprint<4>,  Up: Improved Modules<10>

1.10.4.36 pty
.............

*note pty.spawn(): fbb. now returns the status value from *note
os.waitpid(): dc8. on the child process, instead of ‘None’.
(Contributed by Gregory P. Smith.)


File: python.info,  Node: pydoc<4>,  Next: re<8>,  Prev: pty,  Up: Improved Modules<10>

1.10.4.37 pydoc
...............

The *note pydoc: b5. module is now based directly on the *note
inspect.signature(): 73b. introspection API, allowing it to provide
signature information for a wider variety of callable objects.  This
change also means that ‘__wrapped__’ attributes are now taken into
account when displaying help information.  (Contributed by Larry
Hastings in bpo-19674(1).)

The *note pydoc: b5. module no longer displays the ‘self’ parameter for
already bound methods.  Instead, it aims to always display the exact
current signature of the supplied callable.  (Contributed by Larry
Hastings in bpo-20710(2).)

In addition to the changes that have been made to *note pydoc: b5.
directly, its handling of custom ‘__dir__’ methods and various
descriptor behaviours has also been improved substantially by the
underlying changes in the *note inspect: 7e. module.

As the *note help(): 8e0. builtin is based on *note pydoc: b5, the above
changes also affect the behaviour of ‘help()’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19674

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20710


File: python.info,  Node: re<8>,  Next: resource,  Prev: pydoc<4>,  Up: Improved Modules<10>

1.10.4.38 re
............

New *note fullmatch(): fbe. function and *note Pattern.fullmatch(): fbf.
method anchor the pattern at both ends of the string to match.  This
provides a way to be explicit about the goal of the match, which avoids
a class of subtle bugs where ‘$’ characters get lost during code changes
or the addition of alternatives to an existing regular expression.
(Contributed by Matthew Barnett in bpo-16203(1).)

The repr of *note regex objects: fc0. now includes the pattern and the
flags; the repr of *note match objects: fc1. now includes the start,
end, and the part of the string that matched.  (Contributed by Hugo
Lopes Tavares and Serhiy Storchaka in bpo-13592(2) and bpo-17087(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16203

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13592

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17087


File: python.info,  Node: resource,  Next: select,  Prev: re<8>,  Up: Improved Modules<10>

1.10.4.39 resource
..................

New *note prlimit(): fc3. function, available on Linux platforms with a
kernel version of 2.6.36 or later and glibc of 2.13 or later, provides
the ability to query or set the resource limits for processes other than
the one making the call.  (Contributed by Christian Heimes in
bpo-16595(1).)

On Linux kernel version 2.6.36 or later, there are also some new Linux
specific constants: *note RLIMIT_MSGQUEUE: fc4, *note RLIMIT_NICE: fc5,
*note RLIMIT_RTPRIO: fc6, *note RLIMIT_RTTIME: fc7, and *note
RLIMIT_SIGPENDING: fc8.  (Contributed by Christian Heimes in
bpo-19324(2).)

On FreeBSD version 9 and later, there some new FreeBSD specific
constants: *note RLIMIT_SBSIZE: fc9, *note RLIMIT_SWAP: fca, and *note
RLIMIT_NPTS: fcb.  (Contributed by Claudiu Popa in bpo-19343(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16595

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19324

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19343


File: python.info,  Node: select,  Next: shelve<2>,  Prev: resource,  Up: Improved Modules<10>

1.10.4.40 select
................

*note epoll: fcd. objects now support the context management protocol.
When used in a *note with: 5d5. statement, the *note close(): fce.
method will be called automatically at the end of the block.
(Contributed by Serhiy Storchaka in bpo-16488(1).)

*note devpoll: fcf. objects now have *note fileno(): fd0. and *note
close(): fd1. methods, as well as a new attribute *note closed: fd2.
(Contributed by Victor Stinner in bpo-18794(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16488

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18794


File: python.info,  Node: shelve<2>,  Next: shutil<6>,  Prev: select,  Up: Improved Modules<10>

1.10.4.41 shelve
................

*note Shelf: fd4. instances may now be used in *note with: 5d5.
statements, and will be automatically closed at the end of the ‘with’
block.  (Contributed by Filip Gruszczyński in bpo-13896(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13896


File: python.info,  Node: shutil<6>,  Next: smtpd<3>,  Prev: shelve<2>,  Up: Improved Modules<10>

1.10.4.42 shutil
................

*note copyfile(): a67. now raises a specific *note Error: fd6. subclass,
*note SameFileError: fd7, when the source and destination are the same
file, which allows an application to take appropriate action on this
specific error.  (Contributed by Atsuo Ishimoto and Hynek Schlawack in
bpo-1492704(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1492704


File: python.info,  Node: smtpd<3>,  Next: smtplib<3>,  Prev: shutil<6>,  Up: Improved Modules<10>

1.10.4.43 smtpd
...............

The ‘SMTPServer’ and ‘SMTPChannel’ classes now accept a 'map' keyword
argument which, if specified, is passed in to ‘asynchat.async_chat’ as
its 'map' argument.  This allows an application to avoid affecting the
global socket map.  (Contributed by Vinay Sajip in bpo-11959(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11959


File: python.info,  Node: smtplib<3>,  Next: socket<9>,  Prev: smtpd<3>,  Up: Improved Modules<10>

1.10.4.44 smtplib
.................

*note SMTPException: fda. is now a subclass of *note OSError: 41a, which
allows both socket level errors and SMTP protocol level errors to be
caught in one try/except statement by code that only cares whether or
not an error occurred.  (Contributed by Ned Jackson Lovely in
bpo-2118(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2118


File: python.info,  Node: socket<9>,  Next: sqlite3<9>,  Prev: smtplib<3>,  Up: Improved Modules<10>

1.10.4.45 socket
................

The socket module now supports the *note CAN_BCM: fdc. protocol on
platforms that support it.  (Contributed by Brian Thorne in
bpo-15359(1).)

Socket objects have new methods to get or set their *note inheritable
flag: f30, *note get_inheritable(): f35. and *note set_inheritable():
f36.

The ‘socket.AF_*’ and ‘socket.SOCK_*’ constants are now enumeration
values using the new *note enum: 56. module.  This allows meaningful
names to be printed during debugging, instead of integer “magic
numbers”.

The *note AF_LINK: fdd. constant is now available on BSD and OSX.

*note inet_pton(): 96c. and *note inet_ntop(): fde. are now supported on
Windows.  (Contributed by Atsuo Ishimoto in bpo-7171(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15359

   (2) https://bugs.python.org/issue?@action=redirect&bpo=7171


File: python.info,  Node: sqlite3<9>,  Next: ssl<10>,  Prev: socket<9>,  Up: Improved Modules<10>

1.10.4.46 sqlite3
.................

A new boolean parameter to the *note connect(): 2a8. function, 'uri',
can be used to indicate that the 'database' parameter is a ‘uri’ (see
the SQLite URI documentation(1)).  (Contributed by poq in bpo-13773(2).)

   ---------- Footnotes ----------

   (1) https://www.sqlite.org/uri.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13773


File: python.info,  Node: ssl<10>,  Next: stat,  Prev: sqlite3<9>,  Up: Improved Modules<10>

1.10.4.47 ssl
.............

*note PROTOCOL_TLSv1_1: fe1. and *note PROTOCOL_TLSv1_2: fe2. (TLSv1.1
and TLSv1.2 support) have been added; support for these protocols is
only available if Python is linked with OpenSSL 1.0.1 or later.
(Contributed by Michele Orrù and Antoine Pitrou in bpo-16692(1).)  New
function *note create_default_context(): 155. provides a standard way to
obtain an *note SSLContext: 294. whose settings are intended to be a
reasonable balance between compatibility and security.  These settings
are more stringent than the defaults provided by the ‘SSLContext’
constructor, and may be adjusted in the future, without prior
deprecation, if best-practice security requirements change.  The new
recommended best practice for using stdlib libraries that support SSL is
to use ‘create_default_context()’ to obtain an ‘SSLContext’ object,
modify it if needed, and then pass it as the 'context' argument of the
appropriate stdlib API. (Contributed by Christian Heimes in
bpo-19689(2).)

*note SSLContext: 294. method *note load_verify_locations(): f22.
accepts a new optional argument 'cadata', which can be used to provide
PEM or DER encoded certificates directly via strings or bytes,
respectively.  (Contributed by Christian Heimes in bpo-18138(3).)

New function *note get_default_verify_paths(): fe3. returns a named
tuple of the paths and environment variables that the *note
set_default_verify_paths(): fe4. method uses to set OpenSSL’s default
‘cafile’ and ‘capath’.  This can be an aid in debugging default
verification issues.  (Contributed by Christian Heimes in bpo-18143(4).)

*note SSLContext: 294. has a new method, *note cert_store_stats(): fe5,
that reports the number of loaded ‘X.509’ certs, ‘X.509 CA’ certs, and
certificate revocation lists (‘crl’s), as well as a *note
get_ca_certs(): fe6. method that returns a list of the loaded ‘CA’
certificates.  (Contributed by Christian Heimes in bpo-18147(5).)

If OpenSSL 0.9.8 or later is available, *note SSLContext: 294. has a new
attribute *note verify_flags: fe7. that can be used to control the
certificate verification process by setting it to some combination of
the new constants *note VERIFY_DEFAULT: fe8, *note
VERIFY_CRL_CHECK_LEAF: fe9, *note VERIFY_CRL_CHECK_CHAIN: fea, or *note
VERIFY_X509_STRICT: 157.  OpenSSL does not do any CRL verification by
default.  (Contributed by Christien Heimes in bpo-8813(6).)

New *note SSLContext: 294. method *note load_default_certs(): feb. loads
a set of default “certificate authority” (CA) certificates from default
locations, which vary according to the platform.  It can be used to load
both TLS web server authentication certificates (‘purpose=’*note
SERVER_AUTH: fec.) for a client to use to verify a server, and
certificates for a server to use in verifying client certificates
(‘purpose=’*note CLIENT_AUTH: fed.).  (Contributed by Christian Heimes
in bpo-19292(7).)  Two new windows-only functions, *note
enum_certificates(): fee. and *note enum_crls(): fef. provide the
ability to retrieve certificates, certificate information, and CRLs from
the Windows cert store.  (Contributed by Christian Heimes in
bpo-17134(8).)  Support for server-side SNI (Server Name Indication)
using the new *note ssl.SSLContext.set_servername_callback(): ff0.
method.  (Contributed by Daniel Black in bpo-8109(9).)

The dictionary returned by *note SSLSocket.getpeercert(): ff1. contains
additional ‘X509v3’ extension items: ‘crlDistributionPoints’,
‘calIssuers’, and ‘OCSP’ URIs.  (Contributed by Christian Heimes in
bpo-18379(10).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16692

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19689

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18138

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18143

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18147

   (6) https://bugs.python.org/issue?@action=redirect&bpo=8813

   (7) https://bugs.python.org/issue?@action=redirect&bpo=19292

   (8) https://bugs.python.org/issue?@action=redirect&bpo=17134

   (9) https://bugs.python.org/issue?@action=redirect&bpo=8109

   (10) https://bugs.python.org/issue?@action=redirect&bpo=18379


File: python.info,  Node: stat,  Next: struct<2>,  Prev: ssl<10>,  Up: Improved Modules<10>

1.10.4.48 stat
..............

The *note stat: d1. module is now backed by a C implementation in
‘_stat’.  A C implementation is required as most of the values aren’t
standardized and are platform-dependent.  (Contributed by Christian
Heimes in bpo-11016(1).)

The module supports new *note ST_MODE: ff3. flags, *note S_IFDOOR: ff4,
*note S_IFPORT: ff5, and *note S_IFWHT: ff6.  (Contributed by Christian
Hiemes in bpo-11016(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11016

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11016


File: python.info,  Node: struct<2>,  Next: subprocess<5>,  Prev: stat,  Up: Improved Modules<10>

1.10.4.49 struct
................

New function *note iter_unpack: ff8. and a new *note
struct.Struct.iter_unpack(): ff9. method on compiled formats provide
streamed unpacking of a buffer containing repeated instances of a given
format of data.  (Contributed by Antoine Pitrou in bpo-17804(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17804


File: python.info,  Node: subprocess<5>,  Next: sunau<2>,  Prev: struct<2>,  Up: Improved Modules<10>

1.10.4.50 subprocess
....................

*note check_output(): ffb. now accepts an 'input' argument that can be
used to provide the contents of ‘stdin’ for the command that is run.
(Contributed by Zack Weinberg in bpo-16624(1).)

*note getoutput(): ffc. and *note getstatusoutput(): ffd. now work on
Windows.  This change was actually inadvertently made in 3.3.4.
(Contributed by Tim Golden in bpo-10197(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16624

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10197


File: python.info,  Node: sunau<2>,  Next: sys<12>,  Prev: subprocess<5>,  Up: Improved Modules<10>

1.10.4.51 sunau
...............

The ‘getparams()’ method now returns a namedtuple rather than a plain
tuple.  (Contributed by Claudiu Popa in bpo-18901(1).)

‘sunau.open()’ now supports the context management protocol: when used
in a *note with: 5d5. block, the ‘close’ method of the returned object
will be called automatically at the end of the block.  (Contributed by
Serhiy Storchaka in bpo-18878(2).)

‘AU_write.setsampwidth()’ now supports 24 bit samples, thus adding
support for writing 24 sample using the module.  (Contributed by Serhiy
Storchaka in bpo-19261(3).)

The ‘writeframesraw()’ and ‘writeframes()’ methods now accept any *note
bytes-like object: d55.  (Contributed by Serhiy Storchaka in
bpo-8311(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18901

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18878

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19261

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8311


File: python.info,  Node: sys<12>,  Next: tarfile<8>,  Prev: sunau<2>,  Up: Improved Modules<10>

1.10.4.52 sys
.............

New function *note sys.getallocatedblocks(): 1000. returns the current
number of blocks allocated by the interpreter.  (In CPython with the
default ‘--with-pymalloc’ setting, this is allocations made through the
*note PyObject_Malloc(): c89. API.) This can be useful for tracking
memory leaks, especially if automated via a test suite.  (Contributed by
Antoine Pitrou in bpo-13390(1).)

When the Python interpreter starts in *note interactive mode: 1001, it
checks for an *note __interactivehook__: 1002. attribute on the *note
sys: d9. module.  If the attribute exists, its value is called with no
arguments just before interactive mode is started.  The check is made
after the *note PYTHONSTARTUP: 1003. file is read, so it can be set
there.  The *note site: c7. module *note sets it: 1004. to a function
that enables tab completion and history saving (in ‘~/.python-history’)
if the platform supports *note readline: ba.  If you do not want this
(new) behavior, you can override it in ‘PYTHONSTARTUP’, *note
sitecustomize: c8, or *note usercustomize: 10e. by deleting this
attribute from ‘sys’ (or setting it to some other callable).
(Contributed by Éric Araujo and Antoine Pitrou in bpo-5845(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13390

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5845


File: python.info,  Node: tarfile<8>,  Next: textwrap,  Prev: sys<12>,  Up: Improved Modules<10>

1.10.4.53 tarfile
.................

The *note tarfile: de. module now supports a simple *note Command-Line
Interface: 1006. when called as a script directly or via ‘-m’.  This can
be used to create and extract tarfile archives.  (Contributed by Berker
Peksag in bpo-13477(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13477


File: python.info,  Node: textwrap,  Next: threading<7>,  Prev: tarfile<8>,  Up: Improved Modules<10>

1.10.4.54 textwrap
..................

The *note TextWrapper: 1008. class has two new attributes/constructor
arguments: *note max_lines: 1009, which limits the number of lines in
the output, and *note placeholder: 100a, which is a string that will
appear at the end of the output if it has been truncated because of
'max_lines'.  Building on these capabilities, a new convenience function
*note shorten(): 100b. collapses all of the whitespace in the input to
single spaces and produces a single line of a given 'width' that ends
with the 'placeholder' (by default, ‘[...]’).  (Contributed by Antoine
Pitrou and Serhiy Storchaka in bpo-18585(1) and bpo-18725(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18585

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18725


File: python.info,  Node: threading<7>,  Next: traceback<6>,  Prev: textwrap,  Up: Improved Modules<10>

1.10.4.55 threading
...................

The *note Thread: 956. object representing the main thread can be
obtained from the new *note main_thread(): 100d. function.  In normal
conditions this will be the thread from which the Python interpreter was
started.  (Contributed by Andrew Svetlov in bpo-18882(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18882


File: python.info,  Node: traceback<6>,  Next: types<6>,  Prev: threading<7>,  Up: Improved Modules<10>

1.10.4.56 traceback
...................

A new *note traceback.clear_frames(): 100f. function takes a traceback
object and clears the local variables in all of the frames it
references, reducing the amount of memory consumed.  (Contributed by
Andrew Kuchling in bpo-1565525(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1565525


File: python.info,  Node: types<6>,  Next: urllib<3>,  Prev: traceback<6>,  Up: Improved Modules<10>

1.10.4.57 types
...............

A new *note DynamicClassAttribute(): 62d. descriptor provides a way to
define an attribute that acts normally when looked up through an
instance object, but which is routed to the 'class' ‘__getattr__’ when
looked up through the class.  This allows one to have properties active
on a class, and have virtual attributes on the class with the same name
(see *note enum: 56. for an example).  (Contributed by Ethan Furman in
bpo-19030(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19030


File: python.info,  Node: urllib<3>,  Next: unittest<9>,  Prev: types<6>,  Up: Improved Modules<10>

1.10.4.58 urllib
................

*note urllib.request: 10b. now supports ‘data:’ URLs via the *note
DataHandler: 1012. class.  (Contributed by Mathias Panzenböck in
bpo-16423(1).)

The http method that will be used by a *note Request: 1013. class can
now be specified by setting a *note method: 1014. class attribute on the
subclass.  (Contributed by Jason R Coombs in bpo-18978(2).)

*note Request: 1013. objects are now reusable: if the *note full_url:
1015. or *note data: 1016. attributes are modified, all relevant
internal properties are updated.  This means, for example, that it is
now possible to use the same ‘Request’ object in more than one *note
OpenerDirector.open(): 1017. call with different 'data' arguments, or to
modify a ‘Request’‘s ‘url’ rather than recomputing it from scratch.
There is also a new *note remove_header(): 1018. method that can be used
to remove headers from a ‘Request’.  (Contributed by Alexey Kachayev in
bpo-16464(3), Daniel Wozniak in bpo-17485(4), and Damien Brecht and
Senthil Kumaran in bpo-17272(5).)

*note HTTPError: 1019. objects now have a *note headers: 101a. attribute
that provides access to the HTTP response headers associated with the
error.  (Contributed by Berker Peksag in bpo-15701(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16423

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18978

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16464

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17485

   (5) https://bugs.python.org/issue?@action=redirect&bpo=17272

   (6) https://bugs.python.org/issue?@action=redirect&bpo=15701


File: python.info,  Node: unittest<9>,  Next: venv<7>,  Prev: urllib<3>,  Up: Improved Modules<10>

1.10.4.59 unittest
..................

The *note TestCase: 451. class has a new method, *note subTest(): 101c,
that produces a context manager whose *note with: 5d5. block becomes a
“sub-test”.  This context manager allows a test method to dynamically
generate subtests by, say, calling the ‘subTest’ context manager inside
a loop.  A single test method can thereby produce an indefinite number
of separately identified and separately counted tests, all of which will
run even if one or more of them fail.  For example:

     class NumbersTest(unittest.TestCase):
         def test_even(self):
             for i in range(6):
                 with self.subTest(i=i):
                     self.assertEqual(i % 2, 0)

will result in six subtests, each identified in the unittest verbose
output with a label consisting of the variable name ‘i’ and a particular
value for that variable (‘i=0’, ‘i=1’, etc).  See *note Distinguishing
test iterations using subtests: 101d. for the full version of this
example.  (Contributed by Antoine Pitrou in bpo-16997(1).)

*note unittest.main(): 101e. now accepts an iterable of test names for
'defaultTest', where previously it only accepted a single test name as a
string.  (Contributed by Jyrki Pulliainen in bpo-15132(2).)

If *note SkipTest: 101f. is raised during test discovery (that is, at
the module level in the test file), it is now reported as a skip instead
of an error.  (Contributed by Zach Ware in bpo-16935(3).)

*note discover(): 1020. now sorts the discovered files to provide
consistent test ordering.  (Contributed by Martin Melin and Jeff Ramnani
in bpo-16709(4).)

*note TestSuite: e26. now drops references to tests as soon as the test
has been run, if the test is successful.  On Python interpreters that do
garbage collection, this allows the tests to be garbage collected if
nothing else is holding a reference to the test.  It is possible to
override this behavior by creating a ‘TestSuite’ subclass that defines a
custom ‘_removeTestAtIndex’ method.  (Contributed by Tom Wardill, Matt
McClure, and Andrew Svetlov in bpo-11798(5).)

A new test assertion context-manager, *note assertLogs(): 85f, will
ensure that a given block of code emits a log message using the *note
logging: 87. module.  By default the message can come from any logger
and have a priority of ‘INFO’ or higher, but both the logger name and an
alternative minimum logging level may be specified.  The object returned
by the context manager can be queried for the *note LogRecord: 1021.s
and/or formatted messages that were logged.  (Contributed by Antoine
Pitrou in bpo-18937(6).)

Test discovery now works with namespace packages (Contributed by Claudiu
Popa in bpo-17457(7).)

*note unittest.mock: 107. objects now inspect their specification
signatures when matching calls, which means an argument can now be
matched by either position or name, instead of only by position.
(Contributed by Antoine Pitrou in bpo-17015(8).)

*note mock_open(): 1022. objects now have ‘readline’ and ‘readlines’
methods.  (Contributed by Toshio Kuratomi in bpo-17467(9).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16997

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15132

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16935

   (4) https://bugs.python.org/issue?@action=redirect&bpo=16709

   (5) https://bugs.python.org/issue?@action=redirect&bpo=11798

   (6) https://bugs.python.org/issue?@action=redirect&bpo=18937

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17457

   (8) https://bugs.python.org/issue?@action=redirect&bpo=17015

   (9) https://bugs.python.org/issue?@action=redirect&bpo=17467


File: python.info,  Node: venv<7>,  Next: wave<2>,  Prev: unittest<9>,  Up: Improved Modules<10>

1.10.4.60 venv
..............

*note venv: 111. now includes activation scripts for the ‘csh’ and
‘fish’ shells.  (Contributed by Andrew Svetlov in bpo-15417(1).)

*note EnvBuilder: 26a. and the *note create(): 26b. convenience function
take a new keyword argument 'with_pip', which defaults to ‘False’, that
controls whether or not ‘EnvBuilder’ ensures that ‘pip’ is installed in
the virtual environment.  (Contributed by Nick Coghlan in bpo-19552(2)
as part of the PEP 453(3) implementation.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15417

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19552

   (3) https://peps.python.org/pep-0453/


File: python.info,  Node: wave<2>,  Next: weakref<2>,  Prev: venv<7>,  Up: Improved Modules<10>

1.10.4.61 wave
..............

The *note getparams(): 1025. method now returns a namedtuple rather than
a plain tuple.  (Contributed by Claudiu Popa in bpo-17487(1).)

*note wave.open(): 955. now supports the context management protocol.
(Contributed by Claudiu Popa in bpo-17616(2).)

*note wave: 113. can now *note write output to unseekable files: 1026.
(Contributed by David Jones, Guilherme Polo, and Serhiy Storchaka in
bpo-5202(3).)

The *note writeframesraw(): 1027. and *note writeframes(): 1028. methods
now accept any *note bytes-like object: d55.  (Contributed by Serhiy
Storchaka in bpo-8311(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17487

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17616

   (3) https://bugs.python.org/issue?@action=redirect&bpo=5202

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8311


File: python.info,  Node: weakref<2>,  Next: xml etree<2>,  Prev: wave<2>,  Up: Improved Modules<10>

1.10.4.62 weakref
.................

New *note WeakMethod: 102a. class simulates weak references to bound
methods.  (Contributed by Antoine Pitrou in bpo-14631(1).)

New *note finalize: a8b. class makes it possible to register a callback
to be invoked when an object is garbage collected, without needing to
carefully manage the lifecycle of the weak reference itself.
(Contributed by Richard Oudkerk in bpo-15528(2).)

The callback, if any, associated with a *note ref: 102b. is now exposed
via the *note __callback__: 102c. attribute.  (Contributed by Mark
Dickinson in bpo-17643(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14631

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15528

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17643


File: python.info,  Node: xml etree<2>,  Next: zipfile<5>,  Prev: weakref<2>,  Up: Improved Modules<10>

1.10.4.63 xml.etree
...................

A new parser, *note XMLPullParser: 102e, allows a non-blocking
applications to parse XML documents.  An example can be seen at *note
Pull API for non-blocking parsing: 102f.  (Contributed by Antoine Pitrou
in bpo-17741(1).)

The *note xml.etree.ElementTree: 125. *note tostring(): 1030. and *note
tostringlist(): 1031. functions, and the *note ElementTree: 958. *note
write(): aaa. method, now have a 'short_empty_elements' *note
keyword-only parameter: 2a5. providing control over whether elements
with no content are written in abbreviated (‘<tag />’) or expanded
(‘<tag></tag>’) form.  (Contributed by Ariel Poliak and Serhiy Storchaka
in bpo-14377(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17741

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14377


File: python.info,  Node: zipfile<5>,  Prev: xml etree<2>,  Up: Improved Modules<10>

1.10.4.64 zipfile
.................

The *note writepy(): 1033. method of the *note PyZipFile: 1034. class
has a new 'filterfunc' option that can be used to control which
directories and files are added to the archive.  For example, this could
be used to exclude test files from the archive.  (Contributed by
Christian Tismer in bpo-19274(1).)

The 'allowZip64' parameter to *note ZipFile: 6c7. and *note PyZipFile:
1034. is now ‘True’ by default.  (Contributed by William Mallard in
bpo-17201(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19274

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17201


File: python.info,  Node: CPython Implementation Changes,  Next: Deprecated<11>,  Prev: Improved Modules<10>,  Up: What’s New In Python 3 4

1.10.5 CPython Implementation Changes
-------------------------------------

* Menu:

* PEP 445; Customization of CPython Memory Allocators: PEP 445 Customization of CPython Memory Allocators.
* PEP 442; Safe Object Finalization: PEP 442 Safe Object Finalization.
* PEP 456; Secure and Interchangeable Hash Algorithm: PEP 456 Secure and Interchangeable Hash Algorithm.
* PEP 436; Argument Clinic: PEP 436 Argument Clinic.
* Other Build and C API Changes::
* Other Improvements: Other Improvements<2>.
* Significant Optimizations::


File: python.info,  Node: PEP 445 Customization of CPython Memory Allocators,  Next: PEP 442 Safe Object Finalization,  Up: CPython Implementation Changes

1.10.5.1 PEP 445: Customization of CPython Memory Allocators
............................................................

PEP 445(1) adds new C level interfaces to customize memory allocation in
the CPython interpreter.

See also
........

PEP 445(2) – Add new APIs to customize Python memory allocators

     PEP written and implemented by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0445/

   (2) https://peps.python.org/pep-0445/


File: python.info,  Node: PEP 442 Safe Object Finalization,  Next: PEP 456 Secure and Interchangeable Hash Algorithm,  Prev: PEP 445 Customization of CPython Memory Allocators,  Up: CPython Implementation Changes

1.10.5.2 PEP 442: Safe Object Finalization
..........................................

PEP 442(1) removes the current limitations and quirks of object
finalization in CPython.  With it, objects with *note __del__(): 1038.
methods, as well as generators with *note finally: 9d5. clauses, can be
finalized when they are part of a reference cycle.

As part of this change, module globals are no longer forcibly set to
*note None: 678. during interpreter shutdown in most cases, instead
relying on the normal operation of the cyclic garbage collector.  This
avoids a whole class of interpreter-shutdown-time errors, usually
involving ‘__del__’ methods, that have plagued Python since the cyclic
GC was first introduced.

See also
........

PEP 442(2) – Safe object finalization

     PEP written and implemented by Antoine Pitrou.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0442/

   (2) https://peps.python.org/pep-0442/


File: python.info,  Node: PEP 456 Secure and Interchangeable Hash Algorithm,  Next: PEP 436 Argument Clinic,  Prev: PEP 442 Safe Object Finalization,  Up: CPython Implementation Changes

1.10.5.3 PEP 456: Secure and Interchangeable Hash Algorithm
...........................................................

PEP 456(1) follows up on earlier security fix work done on Python’s hash
algorithm to address certain DOS attacks to which public facing APIs
backed by dictionary lookups may be subject.  (See bpo-14621(2) for the
start of the current round of improvements.)  The PEP unifies CPython’s
hash code to make it easier for a packager to substitute a different
hash algorithm, and switches Python’s default implementation to a
SipHash implementation on platforms that have a 64 bit data type.  Any
performance differences in comparison with the older FNV algorithm are
trivial.

The PEP adds additional fields to the *note sys.hash_info: 103a. named
tuple to describe the hash algorithm in use by the currently executing
binary.  Otherwise, the PEP does not alter any existing CPython APIs.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0456/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14621


File: python.info,  Node: PEP 436 Argument Clinic,  Next: Other Build and C API Changes,  Prev: PEP 456 Secure and Interchangeable Hash Algorithm,  Up: CPython Implementation Changes

1.10.5.4 PEP 436: Argument Clinic
.................................

“Argument Clinic” ( PEP 436(1)) is now part of the CPython build process
and can be used to simplify the process of defining and maintaining
accurate signatures for builtins and standard library extension modules
implemented in C.

Some standard library extension modules have been converted to use
Argument Clinic in Python 3.4, and *note pydoc: b5. and *note inspect:
7e. have been updated accordingly.

It is expected that signature metadata for programmatic introspection
will be added to additional callables implemented in C as part of Python
3.4 maintenance releases.

     Note: The Argument Clinic PEP is not fully up to date with the
     state of the implementation.  This has been deemed acceptable by
     the release manager and core development team in this case, as
     Argument Clinic will not be made available as a public API for
     third party use in Python 3.4.

See also
........

PEP 436(2) – The Argument Clinic DSL

     PEP written and implemented by Larry Hastings.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0436/

   (2) https://peps.python.org/pep-0436/


File: python.info,  Node: Other Build and C API Changes,  Next: Other Improvements<2>,  Prev: PEP 436 Argument Clinic,  Up: CPython Implementation Changes

1.10.5.5 Other Build and C API Changes
......................................

   * The new *note PyType_GetSlot(): 8a3. function has been added to the
     stable ABI, allowing retrieval of function pointers from named type
     slots when using the limited API. (Contributed by Martin von Löwis
     in bpo-17162(1).)

   * The new ‘Py_SetStandardStreamEncoding()’ pre-initialization API
     allows applications embedding the CPython interpreter to reliably
     force a particular encoding and error handler for the standard
     streams.  (Contributed by Bastien Montagne and Nick Coghlan in
     bpo-16129(2).)

   * Most Python C APIs that don’t mutate string arguments are now
     correctly marked as accepting ‘const char *’ rather than ‘char *’.
     (Contributed by Serhiy Storchaka in bpo-1772673(3).)

   * A new shell version of ‘python-config’ can be used even when a
     python interpreter is not available (for example, in cross
     compilation scenarios).

   * *note PyUnicode_FromFormat(): 38d. now supports width and precision
     specifications for ‘%s’, ‘%A’, ‘%U’, ‘%V’, ‘%S’, and ‘%R’.
     (Contributed by Ysj Ray and Victor Stinner in bpo-7330(4).)

   * New function *note PyStructSequence_InitType2(): 103d. supplements
     the existing *note PyStructSequence_InitType(): 103e. function.
     The difference is that it returns ‘0’ on success and ‘-1’ on
     failure.

   * The CPython source can now be compiled using the address sanity
     checking features of recent versions of GCC and clang: the false
     alarms in the small object allocator have been silenced.
     (Contributed by Dhiru Kholia in bpo-18596(5).)

   * The Windows build now uses Address Space Layout Randomization(6)
     and Data Execution Prevention(7).  (Contributed by Christian Heimes
     in bpo-16632(8).)

   * New function *note PyObject_LengthHint(): 103f. is the C API
     equivalent of *note operator.length_hint(): fa6.  (Contributed by
     Armin Ronacher in bpo-16148(9).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17162

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16129

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1772673

   (4) https://bugs.python.org/issue?@action=redirect&bpo=7330

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18596

   (6) https://en.wikipedia.org/wiki/Address_space_layout_randomization

   (7) https://en.wikipedia.org/wiki/Data_Execution_Prevention

   (8) https://bugs.python.org/issue?@action=redirect&bpo=16632

   (9) https://bugs.python.org/issue?@action=redirect&bpo=16148


File: python.info,  Node: Other Improvements<2>,  Next: Significant Optimizations,  Prev: Other Build and C API Changes,  Up: CPython Implementation Changes

1.10.5.6 Other Improvements
...........................

   * The *note python: 1042. command has a new *note option: 1043, ‘-I’,
     which causes it to run in “isolated mode”, which means that *note
     sys.path: 3b7. contains neither the script’s directory nor the
     user’s ‘site-packages’ directory, and all ‘PYTHON*’ environment
     variables are ignored (it implies both ‘-s’ and ‘-E’).  Other
     restrictions may also be applied in the future, with the goal being
     to isolate the execution of a script from the user’s environment.
     This is appropriate, for example, when Python is used to run a
     system script.  On most POSIX systems it can and should be used in
     the ‘#!’ line of system scripts.  (Contributed by Christian Heimes
     in bpo-16499(1).)

   * Tab-completion is now enabled by default in the interactive
     interpreter on systems that support *note readline: ba.  History is
     also enabled by default, and is written to (and read from) the file
     ‘~/.python-history’.  (Contributed by Antoine Pitrou and Éric
     Araujo in bpo-5845(2).)

   * Invoking the Python interpreter with ‘--version’ now outputs the
     version to standard output instead of standard error
     (bpo-18338(3)).  Similar changes were made to *note argparse: 6.
     (bpo-18920(4)) and other modules that have script-like invocation
     capabilities (bpo-18922(5)).

   * The CPython Windows installer now adds ‘.py’ to the ‘PATHEXT’
     variable when extensions are registered, allowing users to run a
     python script at the windows command prompt by just typing its name
     without the ‘.py’ extension.  (Contributed by Paul Moore in
     bpo-18569(6).)

   * A new ‘make’ target coverage-report(7) will build python, run the
     test suite, and generate an HTML coverage report for the C codebase
     using ‘gcov’ and lcov(8).

   * The ‘-R’ option to the *note python regression test suite: 1044.
     now also checks for memory allocation leaks, using *note
     sys.getallocatedblocks(): 1000.  (Contributed by Antoine Pitrou in
     bpo-13390(9).)

   * ‘python -m’ now works with namespace packages.

   * The *note stat: d1. module is now implemented in C, which means it
     gets the values for its constants from the C header files, instead
     of having the values hard-coded in the python module as was
     previously the case.

   * Loading multiple python modules from a single OS module (‘.so’,
     ‘.dll’) now works correctly (previously it silently returned the
     first python module in the file).  (Contributed by Václav Šmilauer
     in bpo-16421(10).)

   * A new opcode, ‘LOAD_CLASSDEREF’, has been added to fix a bug in the
     loading of free variables in class bodies that could be triggered
     by certain uses of *note __prepare__: c7f.  (Contributed by
     Benjamin Peterson in bpo-17853(11).)

   * A number of MemoryError-related crashes were identified and fixed
     by Victor Stinner using his PEP 445(12)-based ‘pyfailmalloc’ tool
     (bpo-18408(13), bpo-18520(14)).

   * The ‘pyvenv’ command now accepts a ‘--copies’ option to use copies
     rather than symlinks even on systems where symlinks are the
     default.  (Contributed by Vinay Sajip in bpo-18807(15).)

   * The ‘pyvenv’ command also accepts a ‘--without-pip’ option to
     suppress the otherwise-automatic bootstrapping of pip into the
     virtual environment.  (Contributed by Nick Coghlan in bpo-19552(16)
     as part of the PEP 453(17) implementation.)

   * The encoding name is now optional in the value set for the *note
     PYTHONIOENCODING: 1045. environment variable.  This makes it
     possible to set just the error handler, without changing the
     default encoding.  (Contributed by Serhiy Storchaka in
     bpo-18818(18).)

   * The *note bz2: 13, *note lzma: 8a, and *note gzip: 67. module
     ‘open’ functions now support ‘x’ (exclusive creation) mode.
     (Contributed by Tim Heaney and Vajrasky Kok in bpo-19201(19),
     bpo-19222(20), and bpo-19223(21).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16499

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5845

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18338

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18920

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18922

   (6) https://bugs.python.org/issue?@action=redirect&bpo=18569

   (7) 
https://devguide.python.org/coverage/#measuring-coverage-of-c-code-with-gcov-and-lcov

   (8) https://github.com/linux-test-project/lcov

   (9) https://bugs.python.org/issue?@action=redirect&bpo=13390

   (10) https://bugs.python.org/issue?@action=redirect&bpo=16421

   (11) https://bugs.python.org/issue?@action=redirect&bpo=17853

   (12) https://peps.python.org/pep-0445/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=18408

   (14) https://bugs.python.org/issue?@action=redirect&bpo=18520

   (15) https://bugs.python.org/issue?@action=redirect&bpo=18807

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19552

   (17) https://peps.python.org/pep-0453/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=18818

   (19) https://bugs.python.org/issue?@action=redirect&bpo=19201

   (20) https://bugs.python.org/issue?@action=redirect&bpo=19222

   (21) https://bugs.python.org/issue?@action=redirect&bpo=19223


File: python.info,  Node: Significant Optimizations,  Prev: Other Improvements<2>,  Up: CPython Implementation Changes

1.10.5.7 Significant Optimizations
..................................

   * The UTF-32 decoder is now 3x to 4x faster.  (Contributed by Serhiy
     Storchaka in bpo-14625(1).)

   * The cost of hash collisions for sets is now reduced.  Each hash
     table probe now checks a series of consecutive, adjacent key/hash
     pairs before continuing to make random probes through the hash
     table.  This exploits cache locality to make collision resolution
     less expensive.  The collision resolution scheme can be described
     as a hybrid of linear probing and open addressing.  The number of
     additional linear probes defaults to nine.  This can be changed at
     compile-time by defining LINEAR_PROBES to be any value.  Set
     LINEAR_PROBES=0 to turn-off linear probing entirely.  (Contributed
     by Raymond Hettinger in bpo-18771(2).)

   * The interpreter starts about 30% faster.  A couple of measures lead
     to the speedup.  The interpreter loads fewer modules on startup,
     e.g.  the *note re: b9, *note collections: 1d. and *note locale:
     86. modules and their dependencies are no longer imported by
     default.  The marshal module has been improved to load compiled
     Python code faster.  (Contributed by Antoine Pitrou, Christian
     Heimes and Victor Stinner in bpo-19219(3), bpo-19218(4),
     bpo-19209(5), bpo-19205(6) and bpo-9548(7).)

   * *note bz2.BZ2File: 86d. is now as fast or faster than the Python2
     version for most cases.  *note lzma.LZMAFile: 1047. has also been
     optimized.  (Contributed by Serhiy Storchaka and Nadeem Vawda in
     bpo-16034(8).)

   * *note random.getrandbits(): 1048. is 20%-40% faster for small
     integers (the most common use case).  (Contributed by Serhiy
     Storchaka in bpo-16674(9).)

   * By taking advantage of the new storage format for strings, pickling
     of strings is now significantly faster.  (Contributed by Victor
     Stinner and Antoine Pitrou in bpo-15596(10).)

   * A performance issue in ‘io.FileIO.readall()’ has been solved.  This
     particularly affects Windows, and significantly speeds up the case
     of piping significant amounts of data through *note subprocess: d6.
     (Contributed by Richard Oudkerk in bpo-15758(11).)

   * *note html.escape(): 1049. is now 10x faster.  (Contributed by Matt
     Bryant in bpo-18020(12).)

   * On Windows, the native ‘VirtualAlloc’ is now used instead of the
     CRT ‘malloc’ in ‘obmalloc’.  Artificial benchmarks show about a 3%
     memory savings.

   * *note os.urandom(): 526. now uses a lazily opened persistent file
     descriptor so as to avoid using many file descriptors when run in
     parallel from multiple threads.  (Contributed by Antoine Pitrou in
     bpo-18756(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14625

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18771

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19219

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19218

   (5) https://bugs.python.org/issue?@action=redirect&bpo=19209

   (6) https://bugs.python.org/issue?@action=redirect&bpo=19205

   (7) https://bugs.python.org/issue?@action=redirect&bpo=9548

   (8) https://bugs.python.org/issue?@action=redirect&bpo=16034

   (9) https://bugs.python.org/issue?@action=redirect&bpo=16674

   (10) https://bugs.python.org/issue?@action=redirect&bpo=15596

   (11) https://bugs.python.org/issue?@action=redirect&bpo=15758

   (12) https://bugs.python.org/issue?@action=redirect&bpo=18020

   (13) https://bugs.python.org/issue?@action=redirect&bpo=18756


File: python.info,  Node: Deprecated<11>,  Next: Removed<11>,  Prev: CPython Implementation Changes,  Up: What’s New In Python 3 4

1.10.6 Deprecated
-----------------

This section covers various APIs and other features that have been
deprecated in Python 3.4, and will be removed in Python 3.5 or later.
In most (but not all) cases, using the deprecated APIs will produce a
*note DeprecationWarning: 1a5. when the interpreter is run with
deprecation warnings enabled (for example, by using ‘-Wd’).

* Menu:

* Deprecations in the Python API::
* Deprecated Features::


File: python.info,  Node: Deprecations in the Python API,  Next: Deprecated Features,  Up: Deprecated<11>

1.10.6.1 Deprecations in the Python API
.......................................

   * As mentioned in *note PEP 451; A ModuleSpec Type for the Import
     System: f10, a number of *note importlib: 77. methods and functions
     are deprecated: ‘importlib.find_loader()’ is replaced by *note
     importlib.util.find_spec(): 2cd.;
     ‘importlib.machinery.PathFinder.find_module()’ is replaced by *note
     importlib.machinery.PathFinder.find_spec(): 104c.;
     ‘importlib.abc.MetaPathFinder.find_module()’ is replaced by *note
     importlib.abc.MetaPathFinder.find_spec(): 86f.;
     ‘importlib.abc.PathEntryFinder.find_loader()’ and ‘find_module()’
     are replaced by *note importlib.abc.PathEntryFinder.find_spec():
     873.; all of the ‘XXXLoader’ ABC ‘load_module’ methods
     (‘importlib.abc.Loader.load_module()’,
     ‘importlib.abc.InspectLoader.load_module()’,
     ‘importlib.abc.FileLoader.load_module()’,
     ‘importlib.abc.SourceLoader.load_module()’) should no longer be
     implemented, instead loaders should implement an ‘exec_module’
     method (*note importlib.abc.Loader.exec_module(): 871, *note
     importlib.abc.InspectLoader.exec_module(): 104d. *note
     importlib.abc.SourceLoader.exec_module(): 104e.) and let the import
     system take care of the rest; and
     ‘importlib.abc.Loader.module_repr()’,
     ‘importlib.util.module_for_loader()’,
     ‘importlib.util.set_loader()’, and ‘importlib.util.set_package()’
     are no longer needed because their functions are now handled
     automatically by the import system.

   * The ‘imp’ module is pending deprecation.  To keep compatibility
     with Python 2/3 code bases, the module’s removal is currently not
     scheduled.

   * The ‘formatter’ module is pending deprecation and is slated for
     removal in Python 3.6.

   * ‘MD5’ as the default 'digestmod' for the *note hmac.new(): ab4.
     function is deprecated.  Python 3.6 will require an explicit digest
     name or constructor as 'digestmod' argument.

   * The internal ‘Netrc’ class in the *note ftplib: 5e. module has been
     documented as deprecated in its docstring for quite some time.  It
     now emits a *note DeprecationWarning: 1a5. and will be removed
     completely in Python 3.5.

   * The undocumented 'endtime' argument to *note
     subprocess.Popen.wait(): d0b. should not have been exposed and is
     hopefully not in use; it is deprecated and will mostly likely be
     removed in Python 3.5.

   * The 'strict' argument of *note HTMLParser: 87e. is deprecated.

   * The *note plistlib: ab. ‘readPlist()’, ‘writePlist()’,
     ‘readPlistFromBytes()’, and ‘writePlistToBytes()’ functions are
     deprecated in favor of the corresponding new functions *note
     load(): 959, *note dump(): 95b, *note loads(): 95a, and *note
     dumps(): 95c.  ‘Data()’ is deprecated in favor of just using the
     *note bytes: 1c2. constructor.

   * The *note sysconfig: db. key ‘SO’ is deprecated, it has been
     replaced by ‘EXT_SUFFIX’.

   * The ‘U’ mode accepted by various ‘open’ functions is deprecated.
     In Python3 it does not do anything useful, and should be replaced
     by appropriate uses of *note io.TextIOWrapper: 7bf. (if needed) and
     its 'newline' argument.

   * The 'parser' argument of *note xml.etree.ElementTree.iterparse():
     273. has been deprecated, as has the 'html' argument of *note
     XMLParser(): a62.  To prepare for the removal of the latter, all
     arguments to ‘XMLParser’ should be passed by keyword.


File: python.info,  Node: Deprecated Features,  Prev: Deprecations in the Python API,  Up: Deprecated<11>

1.10.6.2 Deprecated Features
............................

   * Running *note IDLE — Python editor and shell: 1050. with the ‘-n’
     flag (no subprocess) is deprecated.  However, the feature will not
     be removed until bpo-18823(1) is resolved.

   * The site module adding a “site-python” directory to sys.path, if it
     exists, is deprecated (bpo-19375(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18823

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19375


File: python.info,  Node: Removed<11>,  Next: Porting to Python 3 4,  Prev: Deprecated<11>,  Up: What’s New In Python 3 4

1.10.7 Removed
--------------

* Menu:

* Operating Systems No Longer Supported::
* API and Feature Removals: API and Feature Removals<5>.
* Code Cleanups::


File: python.info,  Node: Operating Systems No Longer Supported,  Next: API and Feature Removals<5>,  Up: Removed<11>

1.10.7.1 Operating Systems No Longer Supported
..............................................

Support for the following operating systems has been removed from the
source and build tools:

   * OS/2 (bpo-16135(1)).

   * Windows 2000 (changeset e52df05b496a).

   * Windows systems where ‘COMSPEC’ points to ‘command.com’
     (bpo-14470(2)).

   * VMS (bpo-16136(3)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16135

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14470

   (3) https://bugs.python.org/issue?@action=redirect&bpo=16136


File: python.info,  Node: API and Feature Removals<5>,  Next: Code Cleanups,  Prev: Operating Systems No Longer Supported,  Up: Removed<11>

1.10.7.2 API and Feature Removals
.................................

The following obsolete and previously deprecated APIs and features have
been removed:

   * The unmaintained ‘Misc/TextMate’ and ‘Misc/vim’ directories have
     been removed (see the devguide(1) for suggestions on what to use
     instead).

   * The ‘SO’ makefile macro is removed (it was replaced by the
     ‘SHLIB_SUFFIX’ and ‘EXT_SUFFIX’ macros) (bpo-16754(2)).

   * The ‘PyThreadState.tick_counter’ field has been removed; its value
     has been meaningless since Python 3.2, when the “new GIL” was
     introduced (bpo-19199(3)).

   * ‘PyLoader’ and ‘PyPycLoader’ have been removed from *note
     importlib: 77.  (Contributed by Taras Lyapun in bpo-15641(4).)

   * The 'strict' argument to *note HTTPConnection: b59. and *note
     HTTPSConnection: b5a. has been removed.  HTTP 0.9-style “Simple
     Responses” are no longer supported.

   * The deprecated *note urllib.request.Request: 1013. getter and
     setter methods ‘add_data’, ‘has_data’, ‘get_data’, ‘get_type’,
     ‘get_host’, ‘get_selector’, ‘set_proxy’, ‘get_origin_req_host’, and
     ‘is_unverifiable’ have been removed (use direct attribute access
     instead).

   * Support for loading the deprecated ‘TYPE_INT64’ has been removed
     from *note marshal: 8d.  (Contributed by Dan Riti in bpo-15480(5).)

   * *note inspect.Signature: 1cf.: positional-only parameters are now
     required to have a valid name.

   * *note object.__format__(): 621. no longer accepts non-empty format
     strings, it now raises a *note TypeError: 2c3. instead.  Using a
     non-empty string has been deprecated since Python 3.2.  This change
     has been made to prevent a situation where previously working (but
     incorrect) code would start failing if an object gained a
     __format__ method, which means that your code may now raise a
     ‘TypeError’ if you are using an ‘'s'’ format code with objects that
     do not have a __format__ method that handles it.  See bpo-7994(6)
     for background.

   * ‘difflib.SequenceMatcher.isbjunk()’ and
     ‘difflib.SequenceMatcher.isbpopular()’ were deprecated in 3.2, and
     have now been removed: use ‘x in sm.bjunk’ and ‘x in sm.bpopular’,
     where 'sm' is a *note SequenceMatcher: 1054. object (bpo-13248(7)).

   ---------- Footnotes ----------

   (1) https://devguide.python.org

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16754

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19199

   (4) https://bugs.python.org/issue?@action=redirect&bpo=15641

   (5) https://bugs.python.org/issue?@action=redirect&bpo=15480

   (6) https://bugs.python.org/issue?@action=redirect&bpo=7994

   (7) https://bugs.python.org/issue?@action=redirect&bpo=13248


File: python.info,  Node: Code Cleanups,  Prev: API and Feature Removals<5>,  Up: Removed<11>

1.10.7.3 Code Cleanups
......................

   * The unused and undocumented internal ‘Scanner’ class has been
     removed from the *note pydoc: b5. module.

   * The private and effectively unused ‘_gestalt’ module has been
     removed, along with the private *note platform: aa. functions
     ‘_mac_ver_lookup’, ‘_mac_ver_gstalt’, and ‘_bcd2str’, which would
     only have ever been called on badly broken OSX systems (see
     bpo-18393(1)).

   * The hardcoded copies of certain *note stat: d1. constants that were
     included in the *note tarfile: de. module namespace have been
     removed.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18393


File: python.info,  Node: Porting to Python 3 4,  Next: Changed in 3 4 3,  Prev: Removed<11>,  Up: What’s New In Python 3 4

1.10.8 Porting to Python 3.4
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Changes in ‘python’ Command Behavior: Changes in ‘python’ Command Behavior<2>.
* Changes in the Python API: Changes in the Python API<10>.
* Changes in the C API: Changes in the C API<8>.


File: python.info,  Node: Changes in ‘python’ Command Behavior<2>,  Next: Changes in the Python API<10>,  Up: Porting to Python 3 4

1.10.8.1 Changes in ‘python’ Command Behavior
.............................................

   * In a posix shell, setting the ‘PATH’ environment variable to an
     empty value is equivalent to not setting it at all.  However,
     setting *note PYTHONPATH: 1058. to an empty value was 'not'
     equivalent to not setting it at all: setting ‘PYTHONPATH’ to an
     empty value was equivalent to setting it to ‘.’, which leads to
     confusion when reasoning by analogy to how ‘PATH’ works.  The
     behavior now conforms to the posix convention for ‘PATH’.

   * The [X refs, Y blocks] output of a debug (‘--with-pydebug’) build
     of the CPython interpreter is now off by default.  It can be
     re-enabled using the ‘-X showrefcount’ option.  (Contributed by
     Ezio Melotti in bpo-17323(1).)

   * The python command and most stdlib scripts (as well as *note
     argparse: 6.) now output ‘--version’ information to ‘stdout’
     instead of ‘stderr’ (for issue list see *note Other Improvements:
     1041. above).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17323


File: python.info,  Node: Changes in the Python API<10>,  Next: Changes in the C API<8>,  Prev: Changes in ‘python’ Command Behavior<2>,  Up: Porting to Python 3 4

1.10.8.2 Changes in the Python API
..................................

   * The ABCs defined in *note importlib.abc: 78. now either raise the
     appropriate exception or return a default value instead of raising
     *note NotImplementedError: 228. blindly.  This will only affect
     code calling *note super(): 4de. and falling through all the way to
     the ABCs.  For compatibility, catch both ‘NotImplementedError’ or
     the appropriate exception as needed.

   * The module type now initializes the *note __package__: 2d7. and
     *note __loader__: 2e2. attributes to ‘None’ by default.  To
     determine if these attributes were set in a backwards-compatible
     fashion, use e.g.  ‘getattr(module, '__loader__', None) is not
     None’.  (bpo-17115(1).)

   * ‘importlib.util.module_for_loader()’ now sets ‘__loader__’ and
     ‘__package__’ unconditionally to properly support reloading.  If
     this is not desired then you will need to set these attributes
     manually.  You can use ‘importlib.util.module_to_load()’ for module
     management.

   * Import now resets relevant attributes (e.g.  ‘__name__’,
     ‘__loader__’, ‘__package__’, ‘__file__’, ‘__cached__’)
     unconditionally when reloading.  Note that this restores a pre-3.3
     behavior in that it means a module is re-found when re-loaded
     (bpo-19413(2)).

   * Frozen packages no longer set ‘__path__’ to a list containing the
     package name, they now set it to an empty list.  The previous
     behavior could cause the import system to do the wrong thing on
     submodule imports if there was also a directory with the same name
     as the frozen package.  The correct way to determine if a module is
     a package or not is to use ‘hasattr(module, '__path__')’
     (bpo-18065(3)).

   * Frozen modules no longer define a ‘__file__’ attribute.  It’s
     semantically incorrect for frozen modules to set the attribute as
     they are not loaded from any explicit location.  If you must know
     that a module comes from frozen code then you can see if the
     module’s ‘__spec__.location’ is set to ‘'frozen'’, check if the
     loader is a subclass of *note importlib.machinery.FrozenImporter:
     105a, or if Python 2 compatibility is necessary you can use
     ‘imp.is_frozen()’.

   * *note py_compile.compile(): a32. now raises *note FileExistsError:
     105b. if the file path it would write to is a symlink or a
     non-regular file.  This is to act as a warning that import will
     overwrite those files with a regular file regardless of what type
     of file path they were originally.

   * *note importlib.abc.SourceLoader.get_source(): 105c. no longer
     raises *note ImportError: 41c. when the source code being loaded
     triggers a *note SyntaxError: 18d. or *note UnicodeDecodeError:
     a20.  As ‘ImportError’ is meant to be raised only when source code
     cannot be found but it should, it was felt to be
     over-reaching/overloading of that meaning when the source code is
     found but improperly structured.  If you were catching ImportError
     before and wish to continue to ignore syntax or decoding issues,
     catch all three exceptions now.

   * *note functools.update_wrapper(): 105d. and *note
     functools.wraps(): f96. now correctly set the ‘__wrapped__’
     attribute to the function being wrapped, even if that function also
     had its ‘__wrapped__’ attribute set.  This means ‘__wrapped__’
     attributes now correctly link a stack of decorated functions rather
     than every ‘__wrapped__’ attribute in the chain referring to the
     innermost function.  Introspection libraries that assumed the
     previous behaviour was intentional can use *note inspect.unwrap():
     f95. to access the first function in the chain that has no
     ‘__wrapped__’ attribute.

   * *note inspect.getfullargspec(): 73c. has been reimplemented on top
     of *note inspect.signature(): 73b. and hence handles a much wider
     variety of callable objects than it did in the past.  It is
     expected that additional builtin and extension module callables
     will gain signature metadata over the course of the Python 3.4
     series.  Code that assumes that ‘inspect.getfullargspec()’ will
     fail on non-Python callables may need to be adjusted accordingly.

   * *note importlib.machinery.PathFinder: 105e. now passes on the
     current working directory to objects in *note sys.path_hooks: 105f.
     for the empty string.  This results in *note
     sys.path_importer_cache: 5e7. never containing ‘''’, thus iterating
     through ‘sys.path_importer_cache’ based on *note sys.path: 3b7.
     will not find all keys.  A module’s ‘__file__’ when imported in the
     current working directory will also now have an absolute path,
     including when using ‘-m’ with the interpreter (except for
     ‘__main__.__file__’ when a script has been executed directly using
     a relative path) (Contributed by Brett Cannon in bpo-18416(4)).  is
     specified on the command-line) (bpo-18416(5)).

   * The removal of the 'strict' argument to *note HTTPConnection: b59.
     and *note HTTPSConnection: b5a. changes the meaning of the
     remaining arguments if you are specifying them positionally rather
     than by keyword.  If you’ve been paying attention to deprecation
     warnings your code should already be specifying any additional
     arguments via keywords.

   * Strings between ‘from __future__ import ...’ statements now
     'always' raise a *note SyntaxError: 18d.  Previously if there was
     no leading docstring, an interstitial string would sometimes be
     ignored.  This brings CPython into compliance with the language
     spec; Jython and PyPy already were.  (bpo-17434(6)).

   * *note ssl.SSLSocket.getpeercert(): ff1. and *note
     ssl.SSLSocket.do_handshake(): ea1. now raise an *note OSError: 41a.
     with ‘ENOTCONN’ when the ‘SSLSocket’ is not connected, instead of
     the previous behavior of raising an *note AttributeError: 34e.  In
     addition, ‘getpeercert()’ will raise a *note ValueError: 202. if
     the handshake has not yet been done.

   * *note base64.b32decode(): 1060. now raises a *note binascii.Error:
     1061. when the input string contains non-b32-alphabet characters,
     instead of a *note TypeError: 2c3.  This particular ‘TypeError’ was
     missed when the other ‘TypeError’s were converted.  (Contributed by
     Serhiy Storchaka in bpo-18011(7).)  Note: this change was also
     inadvertently applied in Python 3.3.3.

   * The ‘file’ attribute is now automatically closed when the creating
     ‘cgi.FieldStorage’ instance is garbage collected.  If you were
     pulling the file object out separately from the ‘cgi.FieldStorage’
     instance and not keeping the instance alive, then you should either
     store the entire ‘cgi.FieldStorage’ instance or read the contents
     of the file before the ‘cgi.FieldStorage’ instance is garbage
     collected.

   * Calling ‘read’ or ‘write’ on a closed SSL socket now raises an
     informative *note ValueError: 202. rather than the previous more
     mysterious *note AttributeError: 34e. (bpo-9177(8)).

   * *note slice.indices(): 1062. no longer produces an *note
     OverflowError: 888. for huge values.  As a consequence of this fix,
     ‘slice.indices()’ now raises a *note ValueError: 202. if given a
     negative length; previously it returned nonsense values
     (bpo-14794(9)).

   * The *note complex: 2f8. constructor, unlike the *note cmath: 18.
     functions, was incorrectly accepting *note float: 2f7. values if an
     object’s ‘__complex__’ special method returned one.  This now
     raises a *note TypeError: 2c3.  (bpo-16290(10).)

   * The *note int: 257. constructor in 3.2 and 3.3 erroneously accepts
     *note float: 2f7. values for the 'base' parameter.  It is unlikely
     anyone was doing this, but if so, it will now raise a *note
     TypeError: 2c3. (bpo-16772(11)).

   * Defaults for keyword-only arguments are now evaluated 'after'
     defaults for regular keyword arguments, instead of before.
     Hopefully no one wrote any code that depends on the previous buggy
     behavior (bpo-16967(12)).

   * Stale thread states are now cleared after *note fork(): 197.  This
     may cause some system resources to be released that previously were
     incorrectly kept perpetually alive (for example, database
     connections kept in thread-local storage).  (bpo-17094(13).)

   * Parameter names in ‘__annotations__’ dicts are now mangled
     properly, similarly to *note __kwdefaults__: 1063.  (Contributed by
     Yury Selivanov in bpo-20625(14).)

   * *note hashlib.hash.name: f80. now always returns the identifier in
     lower case.  Previously some builtin hashes had uppercase names,
     but now that it is a formal public interface the naming has been
     made consistent (bpo-18532(15)).

   * Because *note unittest.TestSuite: e26. now drops references to
     tests after they are run, test harnesses that reuse a *note
     TestSuite: e26. to re-run a set of tests may fail.  Test suites
     should not be re-used in this fashion since it means state is
     retained between test runs, breaking the test isolation that *note
     unittest: 106. is designed to provide.  However, if the lack of
     isolation is considered acceptable, the old behavior can be
     restored by creating a ‘TestSuite’ subclass that defines a
     ‘_removeTestAtIndex’ method that does nothing (see *note
     TestSuite.__iter__(): 1064.) (bpo-11798(16)).

   * *note unittest: 106. now uses *note argparse: 6. for command line
     parsing.  There are certain invalid command forms that used to work
     that are no longer allowed; in theory this should not cause
     backward compatibility issues since the disallowed command forms
     didn’t make any sense and are unlikely to be in use.

   * The *note re.split(): 2a2, *note re.findall(): 1065, and *note
     re.sub(): 2a3. functions, and the *note group(): 1066. and *note
     groups(): 1067. methods of ‘match’ objects now always return a
     'bytes' object when the string to be matched is a *note bytes-like
     object: d55.  Previously the return type matched the input type, so
     if your code was depending on the return value being, say, a
     ‘bytearray’, you will need to change your code.

   * ‘audioop’ functions now raise an error immediately if passed string
     input, instead of failing randomly later on (bpo-16685(17)).

   * The new 'convert_charrefs' argument to *note HTMLParser: 87e.
     currently defaults to ‘False’ for backward compatibility, but will
     eventually be changed to default to ‘True’.  It is recommended that
     you add this keyword, with the appropriate value, to any
     ‘HTMLParser’ calls in your code (bpo-13633(18)).

   * Since the 'digestmod' argument to the *note hmac.new(): ab4.
     function will in the future have no default, all calls to
     ‘hmac.new()’ should be changed to explicitly specify a 'digestmod'
     (bpo-17276(19)).

   * Calling *note sysconfig.get_config_var(): 1068. with the ‘SO’ key,
     or looking ‘SO’ up in the results of a call to *note
     sysconfig.get_config_vars(): 1069. is deprecated.  This key should
     be replaced by ‘EXT_SUFFIX’ or ‘SHLIB_SUFFIX’, depending on the
     context (bpo-19555(20)).

   * Any calls to ‘open’ functions that specify ‘U’ should be modified.
     ‘U’ is ineffective in Python3 and will eventually raise an error if
     used.  Depending on the function, the equivalent of its old Python2
     behavior can be achieved using either a 'newline' argument, or if
     necessary by wrapping the stream in *note TextIOWrapper: 7bf. to
     use its 'newline' argument (bpo-15204(21)).

   * If you use ‘pyvenv’ in a script and desire that pip 'not' be
     installed, you must add ‘--without-pip’ to your command invocation.

   * The default behavior of *note json.dump(): d6d. and *note
     json.dumps(): d6e. when an indent is specified has changed: it no
     longer produces trailing spaces after the item separating commas at
     the ends of lines.  This will matter only if you have tests that
     are doing white-space-sensitive comparisons of such output
     (bpo-16333(22)).

   * *note doctest: 3a. now looks for doctests in extension module
     ‘__doc__’ strings, so if your doctest test discovery includes
     extension modules that have things that look like doctests in them
     you may see test failures you’ve never seen before when running
     your tests (bpo-3158(23)).

   * The *note collections.abc: 1e. module has been slightly refactored
     as part of the Python startup improvements.  As a consequence of
     this, it is no longer the case that importing *note collections:
     1d. automatically imports ‘collections.abc’.  If your program
     depended on the (undocumented) implicit import, you will need to
     add an explicit ‘import collections.abc’ (bpo-20784(24)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17115

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19413

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18065

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18416

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18416

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17434

   (7) https://bugs.python.org/issue?@action=redirect&bpo=18011

   (8) https://bugs.python.org/issue?@action=redirect&bpo=9177

   (9) https://bugs.python.org/issue?@action=redirect&bpo=14794

   (10) https://bugs.python.org/issue?@action=redirect&bpo=16290

   (11) https://bugs.python.org/issue?@action=redirect&bpo=16772

   (12) https://bugs.python.org/issue?@action=redirect&bpo=16967

   (13) https://bugs.python.org/issue?@action=redirect&bpo=17094

   (14) https://bugs.python.org/issue?@action=redirect&bpo=20625

   (15) https://bugs.python.org/issue?@action=redirect&bpo=18532

   (16) https://bugs.python.org/issue?@action=redirect&bpo=11798

   (17) https://bugs.python.org/issue?@action=redirect&bpo=16685

   (18) https://bugs.python.org/issue?@action=redirect&bpo=13633

   (19) https://bugs.python.org/issue?@action=redirect&bpo=17276

   (20) https://bugs.python.org/issue?@action=redirect&bpo=19555

   (21) https://bugs.python.org/issue?@action=redirect&bpo=15204

   (22) https://bugs.python.org/issue?@action=redirect&bpo=16333

   (23) https://bugs.python.org/issue?@action=redirect&bpo=3158

   (24) https://bugs.python.org/issue?@action=redirect&bpo=20784


File: python.info,  Node: Changes in the C API<8>,  Prev: Changes in the Python API<10>,  Up: Porting to Python 3 4

1.10.8.3 Changes in the C API
.............................

   * *note PyEval_EvalFrameEx(): 106b, *note PyObject_Repr(): 106c, and
     *note PyObject_Str(): 106d, along with some other internal C APIs,
     now include a debugging assertion that ensures they are not used in
     situations where they may silently discard a currently active
     exception.  In cases where discarding the active exception is
     expected and desired (for example, because it has already been
     saved locally with *note PyErr_Fetch(): 3f6. or is being
     deliberately replaced with a different exception), an explicit
     *note PyErr_Clear(): 106e. call will be needed to avoid triggering
     the assertion when invoking these operations (directly or
     indirectly) and running against a version of Python that is
     compiled with assertions enabled.

   * *note PyErr_SetImportError(): d66. now sets *note TypeError: 2c3.
     when its 'msg' argument is not set.  Previously only ‘NULL’ was
     returned with no exception set.

   * The result of the *note PyOS_ReadlineFunctionPointer: 589. callback
     must now be a string allocated by *note PyMem_RawMalloc(): 393. or
     *note PyMem_RawRealloc(): 395, or ‘NULL’ if an error occurred,
     instead of a string allocated by *note PyMem_Malloc(): c87. or
     *note PyMem_Realloc(): 106f. (bpo-16742(1))

   * *note PyThread_set_key_value(): 40b. now always set the value.  In
     Python 3.3, the function did nothing if the key already exists (if
     the current value is a non-‘NULL’ pointer).

   * The ‘f_tstate’ (thread state) field of the *note PyFrameObject:
     78c. structure has been removed to fix a bug: see bpo-14432(2) for
     the rationale.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16742

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14432


File: python.info,  Node: Changed in 3 4 3,  Prev: Porting to Python 3 4,  Up: What’s New In Python 3 4

1.10.9 Changed in 3.4.3
-----------------------

* Menu:

* PEP 476; Enabling certificate verification by default for stdlib http clients: PEP 476 Enabling certificate verification by default for stdlib http clients.


File: python.info,  Node: PEP 476 Enabling certificate verification by default for stdlib http clients,  Up: Changed in 3 4 3

1.10.9.1 PEP 476: Enabling certificate verification by default for stdlib http clients
......................................................................................

*note http.client: 6f. and modules which use it, such as *note
urllib.request: 10b. and *note xmlrpc.client: 12e, will now verify that
the server presents a certificate which is signed by a CA in the
platform trust store and whose hostname matches the hostname being
requested by default, significantly improving security for many
applications.

For applications which require the old previous behavior, they can pass
an alternate context:

     import urllib.request
     import ssl

     # This disables all verification
     context = ssl._create_unverified_context()

     # This allows using a specific certificate for the host, which doesn't need
     # to be in the trust store
     context = ssl.create_default_context(cafile="/path/to/file.crt")

     urllib.request.urlopen("https://invalid-cert", context=context)


File: python.info,  Node: What’s New In Python 3 3,  Next: What’s New In Python 3 2,  Prev: What’s New In Python 3 4,  Up: What’s New in Python

1.11 What’s New In Python 3.3
=============================

This article explains the new features in Python 3.3, compared to 3.2.
Python 3.3 was released on September 29, 2012.  For full details, see
the changelog(1).

See also
........

PEP 398(2) - Python 3.3 Release Schedule

* Menu:

* Summary – Release highlights: Summary – Release highlights<8>.
* PEP 405; Virtual Environments: PEP 405 Virtual Environments.
* PEP 420; Implicit Namespace Packages: PEP 420 Implicit Namespace Packages.
* PEP 3118; New memoryview implementation and buffer protocol documentation: PEP 3118 New memoryview implementation and buffer protocol documentation.
* PEP 393; Flexible String Representation: PEP 393 Flexible String Representation.
* PEP 397; Python Launcher for Windows: PEP 397 Python Launcher for Windows.
* PEP 3151; Reworking the OS and IO exception hierarchy: PEP 3151 Reworking the OS and IO exception hierarchy.
* PEP 380; Syntax for Delegating to a Subgenerator: PEP 380 Syntax for Delegating to a Subgenerator.
* PEP 409; Suppressing exception context: PEP 409 Suppressing exception context.
* PEP 414; Explicit Unicode literals: PEP 414 Explicit Unicode literals.
* PEP 3155; Qualified name for classes and functions: PEP 3155 Qualified name for classes and functions.
* PEP 412; Key-Sharing Dictionary: PEP 412 Key-Sharing Dictionary.
* PEP 362; Function Signature Object: PEP 362 Function Signature Object.
* PEP 421; Adding sys.implementation: PEP 421 Adding sys implementation.
* Using importlib as the Implementation of Import::
* Other Language Changes: Other Language Changes<11>.
* A Finer-Grained Import Lock::
* Builtin functions and types::
* New Modules: New Modules<11>.
* Improved Modules: Improved Modules<11>.
* Optimizations: Optimizations<10>.
* Build and C API Changes: Build and C API Changes<4>.
* Deprecated: Deprecated<12>.
* Porting to Python 3.3: Porting to Python 3 3.

   ---------- Footnotes ----------

   (1) https://docs.python.org/3.3/whatsnew/changelog.html

   (2) https://peps.python.org/pep-0398/


File: python.info,  Node: Summary – Release highlights<8>,  Next: PEP 405 Virtual Environments,  Up: What’s New In Python 3 3

1.11.1 Summary – Release highlights
-----------------------------------

New syntax features:

   * New ‘yield from’ expression for *note generator delegation: 1077.

   * The ‘u'unicode'’ syntax is accepted again for *note str: 44f.
     objects.

New library modules:

   * *note faulthandler: 58. (helps debugging low-level crashes)

   * *note ipaddress: 80. (high-level objects representing IP addresses
     and masks)

   * *note lzma: 8a. (compress data using the XZ / LZMA algorithm)

   * *note unittest.mock: 107. (replace parts of your system under test
     with mock objects)

   * *note venv: 111. (Python *note virtual environments: 1078, as in
     the popular ‘virtualenv’ package)

New built-in features:

   * Reworked *note I/O exception hierarchy: 1079.

Implementation improvements:

   * Rewritten *note import machinery: 107a. based on *note importlib:
     77.

   * More compact *note unicode strings: 107b.

   * More compact *note attribute dictionaries: 107c.

Significantly Improved Library Modules:

   * C Accelerator for the *note decimal: 107d. module.

   * Better unicode handling in the *note email: 107e. module (*note
     provisional: 107f.).

Security improvements:

   * Hash randomization is switched on by default.

Please read on for a comprehensive list of user-facing changes.


File: python.info,  Node: PEP 405 Virtual Environments,  Next: PEP 420 Implicit Namespace Packages,  Prev: Summary – Release highlights<8>,  Up: What’s New In Python 3 3

1.11.2 PEP 405: Virtual Environments
------------------------------------

Virtual environments help create separate Python setups while sharing a
system-wide base install, for ease of maintenance.  Virtual environments
have their own set of private site packages (i.e.  locally installed
libraries), and are optionally segregated from the system-wide site
packages.  Their concept and implementation are inspired by the popular
‘virtualenv’ third-party package, but benefit from tighter integration
with the interpreter core.

This PEP adds the *note venv: 111. module for programmatic access, and
the ‘pyvenv’ script for command-line access and administration.  The
Python interpreter checks for a ‘pyvenv.cfg’, file whose existence
signals the base of a virtual environment’s directory tree.

See also
........

PEP 405(1) - Python Virtual Environments

     PEP written by Carl Meyer; implementation by Carl Meyer and Vinay
     Sajip

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0405/


File: python.info,  Node: PEP 420 Implicit Namespace Packages,  Next: PEP 3118 New memoryview implementation and buffer protocol documentation,  Prev: PEP 405 Virtual Environments,  Up: What’s New In Python 3 3

1.11.3 PEP 420: Implicit Namespace Packages
-------------------------------------------

Native support for package directories that don’t require ‘__init__.py’
marker files and can automatically span multiple path segments (inspired
by various third party approaches to namespace packages, as described in
PEP 420(1))

See also
........

PEP 420(2) - Implicit Namespace Packages

     PEP written by Eric V. Smith; implementation by Eric V. Smith and
     Barry Warsaw

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0420/

   (2) https://peps.python.org/pep-0420/


File: python.info,  Node: PEP 3118 New memoryview implementation and buffer protocol documentation,  Next: PEP 393 Flexible String Representation,  Prev: PEP 420 Implicit Namespace Packages,  Up: What’s New In Python 3 3

1.11.4 PEP 3118: New memoryview implementation and buffer protocol documentation
--------------------------------------------------------------------------------

The implementation of PEP 3118(1) has been significantly improved.

The new memoryview implementation comprehensively fixes all ownership
and lifetime issues of dynamically allocated fields in the Py_buffer
struct that led to multiple crash reports.  Additionally, several
functions that crashed or returned incorrect results for non-contiguous
or multi-dimensional input have been fixed.

The memoryview object now has a PEP-3118 compliant getbufferproc() that
checks the consumer’s request type.  Many new features have been added,
most of them work in full generality for non-contiguous arrays and
arrays with suboffsets.

The documentation has been updated, clearly spelling out
responsibilities for both exporters and consumers.  Buffer request flags
are grouped into basic and compound flags.  The memory layout of
non-contiguous and multi-dimensional NumPy-style arrays is explained.

* Menu:

* Features::
* API changes::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/


File: python.info,  Node: Features,  Next: API changes,  Up: PEP 3118 New memoryview implementation and buffer protocol documentation

1.11.4.1 Features
.................

   * All native single character format specifiers in struct module
     syntax (optionally prefixed with ‘@’) are now supported.

   * With some restrictions, the cast() method allows changing of format
     and shape of C-contiguous arrays.

   * Multi-dimensional list representations are supported for any array
     type.

   * Multi-dimensional comparisons are supported for any array type.

   * One-dimensional memoryviews of hashable (read-only) types with
     formats B, b or c are now hashable.  (Contributed by Antoine Pitrou
     in bpo-13411(1).)

   * Arbitrary slicing of any 1-D arrays type is supported.  For
     example, it is now possible to reverse a memoryview in 'O'(1) by
     using a negative step.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13411


File: python.info,  Node: API changes,  Prev: Features,  Up: PEP 3118 New memoryview implementation and buffer protocol documentation

1.11.4.2 API changes
....................

   * The maximum number of dimensions is officially limited to 64.

   * The representation of empty shape, strides and suboffsets is now an
     empty tuple instead of ‘None’.

   * Accessing a memoryview element with format ‘B’ (unsigned bytes) now
     returns an integer (in accordance with the struct module syntax).
     For returning a bytes object the view must be cast to ‘c’ first.

   * memoryview comparisons now use the logical structure of the
     operands and compare all array elements by value.  All format
     strings in struct module syntax are supported.  Views with
     unrecognised format strings are still permitted, but will always
     compare as unequal, regardless of view contents.

   * For further changes see *note Build and C API Changes: 1086. and
     *note Porting C code: 1087.

(Contributed by Stefan Krah in bpo-10181(1).)

See also
........

PEP 3118(2) - Revising the Buffer Protocol

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10181

   (2) https://peps.python.org/pep-3118/


File: python.info,  Node: PEP 393 Flexible String Representation,  Next: PEP 397 Python Launcher for Windows,  Prev: PEP 3118 New memoryview implementation and buffer protocol documentation,  Up: What’s New In Python 3 3

1.11.5 PEP 393: Flexible String Representation
----------------------------------------------

The Unicode string type is changed to support multiple internal
representations, depending on the character with the largest Unicode
ordinal (1, 2, or 4 bytes) in the represented string.  This allows a
space-efficient representation in common cases, but gives access to full
UCS-4 on all systems.  For compatibility with existing APIs, several
representations may exist in parallel; over time, this compatibility
should be phased out.

On the Python side, there should be no downside to this change.

On the C API side, PEP 393(1) is fully backward compatible.  The legacy
API should remain available at least five years.  Applications using the
legacy API will not fully benefit of the memory reduction, or - worse -
may use a bit more memory, because Python may have to maintain two
versions of each string (in the legacy format and in the new efficient
storage).

* Menu:

* Functionality::
* Performance and resource usage::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/


File: python.info,  Node: Functionality,  Next: Performance and resource usage,  Up: PEP 393 Flexible String Representation

1.11.5.1 Functionality
......................

Changes introduced by PEP 393(1) are the following:

   * Python now always supports the full range of Unicode code points,
     including non-BMP ones (i.e.  from ‘U+0000’ to ‘U+10FFFF’).  The
     distinction between narrow and wide builds no longer exists and
     Python now behaves like a wide build, even under Windows.

   * With the death of narrow builds, the problems specific to narrow
     builds have also been fixed, for example:

        * *note len(): 631. now always returns 1 for non-BMP characters,
          so ‘len('\U0010FFFF') == 1’;

        * surrogate pairs are not recombined in string literals, so
          ‘'\uDBFF\uDFFF' != '\U0010FFFF'’;

        * indexing or slicing non-BMP characters returns the expected
          value, so ‘'\U0010FFFF'[0]’ now returns ‘'\U0010FFFF'’ and not
          ‘'\uDBFF'’;

        * all other functions in the standard library now correctly
          handle non-BMP code points.

   * The value of *note sys.maxunicode: 108a. is now always ‘1114111’
     (‘0x10FFFF’ in hexadecimal).  The ‘PyUnicode_GetMax()’ function
     still returns either ‘0xFFFF’ or ‘0x10FFFF’ for backward
     compatibility, and it should not be used with the new Unicode API
     (see bpo-13054(2)).

   * The ‘./configure’ flag ‘--with-wide-unicode’ has been removed.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13054


File: python.info,  Node: Performance and resource usage,  Prev: Functionality,  Up: PEP 393 Flexible String Representation

1.11.5.2 Performance and resource usage
.......................................

The storage of Unicode strings now depends on the highest code point in
the string:

   * pure ASCII and Latin1 strings (‘U+0000-U+00FF’) use 1 byte per code
     point;

   * BMP strings (‘U+0000-U+FFFF’) use 2 bytes per code point;

   * non-BMP strings (‘U+10000-U+10FFFF’) use 4 bytes per code point.

The net effect is that for most applications, memory usage of string
storage should decrease significantly - especially compared to former
wide unicode builds - as, in many cases, strings will be pure ASCII even
in international contexts (because many strings store non-human language
data, such as XML fragments, HTTP headers, JSON-encoded data, etc.).  We
also hope that it will, for the same reasons, increase CPU cache
efficiency on non-trivial applications.  The memory usage of Python 3.3
is two to three times smaller than Python 3.2, and a little bit better
than Python 2.7, on a Django benchmark (see the PEP for details).

See also
........

PEP 393(1) - Flexible String Representation

     PEP written by Martin von Löwis; implementation by Torsten Becker
     and Martin von Löwis.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/


File: python.info,  Node: PEP 397 Python Launcher for Windows,  Next: PEP 3151 Reworking the OS and IO exception hierarchy,  Prev: PEP 393 Flexible String Representation,  Up: What’s New In Python 3 3

1.11.6 PEP 397: Python Launcher for Windows
-------------------------------------------

The Python 3.3 Windows installer now includes a ‘py’ launcher
application that can be used to launch Python applications in a version
independent fashion.

This launcher is invoked implicitly when double-clicking ‘*.py’ files.
If only a single Python version is installed on the system, that version
will be used to run the file.  If multiple versions are installed, the
most recent version is used by default, but this can be overridden by
including a Unix-style “shebang line” in the Python script.

The launcher can also be used explicitly from the command line as the
‘py’ application.  Running ‘py’ follows the same version selection rules
as implicitly launching scripts, but a more specific version can be
selected by passing appropriate arguments (such as ‘-3’ to request
Python 3 when Python 2 is also installed, or ‘-2.6’ to specifically
request an earlier Python version when a more recent version is
installed).

In addition to the launcher, the Windows installer now includes an
option to add the newly installed Python to the system PATH.
(Contributed by Brian Curtin in bpo-3561(1).)

See also
........

PEP 397(2) - Python Launcher for Windows

     PEP written by Mark Hammond and Martin v.  Löwis; implementation by
     Vinay Sajip.

Launcher documentation: *note Python Launcher for Windows: 5c1.

Installer PATH modification: *note Finding the Python executable: 108e.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3561

   (2) https://peps.python.org/pep-0397/


File: python.info,  Node: PEP 3151 Reworking the OS and IO exception hierarchy,  Next: PEP 380 Syntax for Delegating to a Subgenerator,  Prev: PEP 397 Python Launcher for Windows,  Up: What’s New In Python 3 3

1.11.7 PEP 3151: Reworking the OS and IO exception hierarchy
------------------------------------------------------------

The hierarchy of exceptions raised by operating system errors is now
both simplified and finer-grained.

You don’t have to worry anymore about choosing the appropriate exception
type between *note OSError: 41a, *note IOError: 1090, *note
EnvironmentError: 1091, *note WindowsError: 1092, ‘mmap.error’, *note
socket.error: 1093. or *note select.error: 1094.  All these exception
types are now only one: ‘OSError’.  The other names are kept as aliases
for compatibility reasons.

Also, it is now easier to catch a specific error condition.  Instead of
inspecting the ‘errno’ attribute (or ‘args[0]’) for a particular
constant from the *note errno: 57. module, you can catch the adequate
*note OSError: 41a. subclass.  The available subclasses are the
following:

   * *note BlockingIOError: 1095.

   * *note ChildProcessError: 1096.

   * *note ConnectionError: e3c.

   * *note FileExistsError: 105b.

   * *note FileNotFoundError: 42e.

   * *note InterruptedError: db6.

   * *note IsADirectoryError: 1097.

   * *note NotADirectoryError: 1098.

   * *note PermissionError: d6b.

   * *note ProcessLookupError: 1099.

   * *note TimeoutError: 83b.

And the *note ConnectionError: e3c. itself has finer-grained subclasses:

   * *note BrokenPipeError: 109a.

   * *note ConnectionAbortedError: 109b.

   * *note ConnectionRefusedError: 109c.

   * *note ConnectionResetError: 109d.

Thanks to the new exceptions, common usages of the *note errno: 57. can
now be avoided.  For example, the following code written for Python 3.2:

     from errno import ENOENT, EACCES, EPERM

     try:
         with open("document.txt") as f:
             content = f.read()
     except IOError as err:
         if err.errno == ENOENT:
             print("document.txt file is missing")
         elif err.errno in (EACCES, EPERM):
             print("You are not allowed to read document.txt")
         else:
             raise

can now be written without the *note errno: 57. import and without
manual inspection of exception attributes:

     try:
         with open("document.txt") as f:
             content = f.read()
     except FileNotFoundError:
         print("document.txt file is missing")
     except PermissionError:
         print("You are not allowed to read document.txt")

See also
........

PEP 3151(1) - Reworking the OS and IO Exception Hierarchy

     PEP written and implemented by Antoine Pitrou

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3151/


File: python.info,  Node: PEP 380 Syntax for Delegating to a Subgenerator,  Next: PEP 409 Suppressing exception context,  Prev: PEP 3151 Reworking the OS and IO exception hierarchy,  Up: What’s New In Python 3 3

1.11.8 PEP 380: Syntax for Delegating to a Subgenerator
-------------------------------------------------------

PEP 380 adds the ‘yield from’ expression, allowing a *note generator:
109f. to delegate part of its operations to another generator.  This
allows a section of code containing *note yield: 9d8. to be factored out
and placed in another generator.  Additionally, the subgenerator is
allowed to return with a value, and the value is made available to the
delegating generator.

While designed primarily for use in delegating to a subgenerator, the
‘yield from’ expression actually allows delegation to arbitrary
subiterators.

For simple iterators, ‘yield from iterable’ is essentially just a
shortened form of ‘for item in iterable: yield item’:

     >>> def g(x):
     ...     yield from range(x, 0, -1)
     ...     yield from range(x)
     ...
     >>> list(g(5))
     [5, 4, 3, 2, 1, 0, 1, 2, 3, 4]

However, unlike an ordinary loop, ‘yield from’ allows subgenerators to
receive sent and thrown values directly from the calling scope, and
return a final value to the outer generator:

     >>> def accumulate():
     ...     tally = 0
     ...     while 1:
     ...         next = yield
     ...         if next is None:
     ...             return tally
     ...         tally += next
     ...
     >>> def gather_tallies(tallies):
     ...     while 1:
     ...         tally = yield from accumulate()
     ...         tallies.append(tally)
     ...
     >>> tallies = []
     >>> acc = gather_tallies(tallies)
     >>> next(acc)  # Ensure the accumulator is ready to accept values
     >>> for i in range(4):
     ...     acc.send(i)
     ...
     >>> acc.send(None)  # Finish the first tally
     >>> for i in range(5):
     ...     acc.send(i)
     ...
     >>> acc.send(None)  # Finish the second tally
     >>> tallies
     [6, 10]

The main principle driving this change is to allow even generators that
are designed to be used with the ‘send’ and ‘throw’ methods to be split
into multiple subgenerators as easily as a single large function can be
split into multiple subfunctions.

See also
........

PEP 380(1) - Syntax for Delegating to a Subgenerator

     PEP written by Greg Ewing; implementation by Greg Ewing, integrated
     into 3.3 by Renaud Blanch, Ryan Kelly and Nick Coghlan;
     documentation by Zbigniew Jędrzejewski-Szmek and Nick Coghlan

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0380/


File: python.info,  Node: PEP 409 Suppressing exception context,  Next: PEP 414 Explicit Unicode literals,  Prev: PEP 380 Syntax for Delegating to a Subgenerator,  Up: What’s New In Python 3 3

1.11.9 PEP 409: Suppressing exception context
---------------------------------------------

PEP 409 introduces new syntax that allows the display of the chained
exception context to be disabled.  This allows cleaner error messages in
applications that convert between exception types:

     >>> class D:
     ...     def __init__(self, extra):
     ...         self._extra_attributes = extra
     ...     def __getattr__(self, attr):
     ...         try:
     ...             return self._extra_attributes[attr]
     ...         except KeyError:
     ...             raise AttributeError(attr) from None
     ...
     >>> D({}).x
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 8, in __getattr__
     AttributeError: x

Without the ‘from None’ suffix to suppress the cause, the original
exception would be displayed by default:

     >>> class C:
     ...     def __init__(self, extra):
     ...         self._extra_attributes = extra
     ...     def __getattr__(self, attr):
     ...         try:
     ...             return self._extra_attributes[attr]
     ...         except KeyError:
     ...             raise AttributeError(attr)
     ...
     >>> C({}).x
     Traceback (most recent call last):
       File "<stdin>", line 6, in __getattr__
     KeyError: 'x'

     During handling of the above exception, another exception occurred:

     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 8, in __getattr__
     AttributeError: x

No debugging capability is lost, as the original exception context
remains available if needed (for example, if an intervening library has
incorrectly suppressed valuable underlying details):

     >>> try:
     ...     D({}).x
     ... except AttributeError as exc:
     ...     print(repr(exc.__context__))
     ...
     KeyError('x',)

See also
........

PEP 409(1) - Suppressing exception context

     PEP written by Ethan Furman; implemented by Ethan Furman and Nick
     Coghlan.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0409/


File: python.info,  Node: PEP 414 Explicit Unicode literals,  Next: PEP 3155 Qualified name for classes and functions,  Prev: PEP 409 Suppressing exception context,  Up: What’s New In Python 3 3

1.11.10 PEP 414: Explicit Unicode literals
------------------------------------------

To ease the transition from Python 2 for Unicode aware Python
applications that make heavy use of Unicode literals, Python 3.3 once
again supports the “‘u’” prefix for string literals.  This prefix has no
semantic significance in Python 3, it is provided solely to reduce the
number of purely mechanical changes in migrating to Python 3, making it
easier for developers to focus on the more significant semantic changes
(such as the stricter default separation of binary and text data).

See also
........

PEP 414(1) - Explicit Unicode literals

     PEP written by Armin Ronacher.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0414/


File: python.info,  Node: PEP 3155 Qualified name for classes and functions,  Next: PEP 412 Key-Sharing Dictionary,  Prev: PEP 414 Explicit Unicode literals,  Up: What’s New In Python 3 3

1.11.11 PEP 3155: Qualified name for classes and functions
----------------------------------------------------------

Functions and class objects have a new *note __qualname__: 10a3.
attribute representing the “path” from the module top-level to their
definition.  For global functions and classes, this is the same as *note
__name__: 10a4.  For other functions and classes, it provides better
information about where they were actually defined, and how they might
be accessible from the global scope.

Example with (non-bound) methods:

     >>> class C:
     ...     def meth(self):
     ...         pass
     ...
     >>> C.meth.__name__
     'meth'
     >>> C.meth.__qualname__
     'C.meth'

Example with nested classes:

     >>> class C:
     ...     class D:
     ...         def meth(self):
     ...             pass
     ...
     >>> C.D.__name__
     'D'
     >>> C.D.__qualname__
     'C.D'
     >>> C.D.meth.__name__
     'meth'
     >>> C.D.meth.__qualname__
     'C.D.meth'

Example with nested functions:

     >>> def outer():
     ...     def inner():
     ...         pass
     ...     return inner
     ...
     >>> outer().__name__
     'inner'
     >>> outer().__qualname__
     'outer.<locals>.inner'

The string representation of those objects is also changed to include
the new, more precise information:

     >>> str(C.D)
     "<class '__main__.C.D'>"
     >>> str(C.D.meth)
     '<function C.D.meth at 0x7f46b9fe31e0>'

See also
........

PEP 3155(1) - Qualified name for classes and functions

     PEP written and implemented by Antoine Pitrou.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3155/


File: python.info,  Node: PEP 412 Key-Sharing Dictionary,  Next: PEP 362 Function Signature Object,  Prev: PEP 3155 Qualified name for classes and functions,  Up: What’s New In Python 3 3

1.11.12 PEP 412: Key-Sharing Dictionary
---------------------------------------

Dictionaries used for the storage of objects’ attributes are now able to
share part of their internal storage between each other (namely, the
part which stores the keys and their respective hashes).  This reduces
the memory consumption of programs creating many instances of
non-builtin types.

See also
........

PEP 412(1) - Key-Sharing Dictionary

     PEP written and implemented by Mark Shannon.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0412/


File: python.info,  Node: PEP 362 Function Signature Object,  Next: PEP 421 Adding sys implementation,  Prev: PEP 412 Key-Sharing Dictionary,  Up: What’s New In Python 3 3

1.11.13 PEP 362: Function Signature Object
------------------------------------------

A new function *note inspect.signature(): 73b. makes introspection of
python callables easy and straightforward.  A broad range of callables
is supported: python functions, decorated or not, classes, and *note
functools.partial(): 417. objects.  New classes *note inspect.Signature:
1cf, *note inspect.Parameter: 1d0. and *note inspect.BoundArguments:
10a7. hold information about the call signatures, such as, annotations,
default values, parameters kinds, and bound arguments, which
considerably simplifies writing decorators and any code that validates
or amends calling signatures or arguments.

See also
........

PEP 362(1): - Function Signature Object

     PEP written by Brett Cannon, Yury Selivanov, Larry Hastings, Jiwon
     Seo; implemented by Yury Selivanov.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0362/


File: python.info,  Node: PEP 421 Adding sys implementation,  Next: Using importlib as the Implementation of Import,  Prev: PEP 362 Function Signature Object,  Up: What’s New In Python 3 3

1.11.14 PEP 421: Adding sys.implementation
------------------------------------------

A new attribute on the *note sys: d9. module exposes details specific to
the implementation of the currently running interpreter.  The initial
set of attributes on *note sys.implementation: 51a. are ‘name’,
‘version’, ‘hexversion’, and ‘cache_tag’.

The intention of ‘sys.implementation’ is to consolidate into one
namespace the implementation-specific data used by the standard library.
This allows different Python implementations to share a single standard
library code base much more easily.  In its initial state,
‘sys.implementation’ holds only a small portion of the
implementation-specific data.  Over time that ratio will shift in order
to make the standard library more portable.

One example of improved standard library portability is ‘cache_tag’.  As
of Python 3.3, ‘sys.implementation.cache_tag’ is used by *note
importlib: 77. to support PEP 3147(1) compliance.  Any Python
implementation that uses ‘importlib’ for its built-in import system may
use ‘cache_tag’ to control the caching behavior for modules.

* Menu:

* SimpleNamespace::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: SimpleNamespace,  Up: PEP 421 Adding sys implementation

1.11.14.1 SimpleNamespace
.........................

The implementation of ‘sys.implementation’ also introduces a new type to
Python: *note types.SimpleNamespace: 1d1.  In contrast to a
mapping-based namespace, like *note dict: 256, ‘SimpleNamespace’ is
attribute-based, like *note object: a9b.  However, unlike ‘object’,
‘SimpleNamespace’ instances are writable.  This means that you can add,
remove, and modify the namespace through normal attribute access.

See also
........

PEP 421(1) - Adding sys.implementation

     PEP written and implemented by Eric Snow.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0421/


File: python.info,  Node: Using importlib as the Implementation of Import,  Next: Other Language Changes<11>,  Prev: PEP 421 Adding sys implementation,  Up: What’s New In Python 3 3

1.11.15 Using importlib as the Implementation of Import
-------------------------------------------------------

bpo-2377(1) - Replace __import__ w/ importlib.__import__ bpo-13959(2) -
Re-implement parts of ‘imp’ in pure Python bpo-14605(3) - Make import
machinery explicit bpo-14646(4) - Require loaders set __loader__ and
__package__

The *note __import__(): 8dd. function is now powered by *note
importlib.__import__(): 10ab.  This work leads to the completion of
“phase 2” of PEP 302(5).  There are multiple benefits to this change.
First, it has allowed for more of the machinery powering import to be
exposed instead of being implicit and hidden within the C code.  It also
provides a single implementation for all Python VMs supporting Python
3.3 to use, helping to end any VM-specific deviations in import
semantics.  And finally it eases the maintenance of import, allowing for
future growth to occur.

For the common user, there should be no visible change in semantics.
For those whose code currently manipulates import or calls import
programmatically, the code changes that might possibly be required are
covered in the *note Porting Python code: 10ac. section of this
document.

* Menu:

* New APIs::
* Visible Changes::

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2377

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13959

   (3) https://bugs.python.org/issue?@action=redirect&bpo=14605

   (4) https://bugs.python.org/issue?@action=redirect&bpo=14646

   (5) https://peps.python.org/pep-0302/


File: python.info,  Node: New APIs,  Next: Visible Changes,  Up: Using importlib as the Implementation of Import

1.11.15.1 New APIs
..................

One of the large benefits of this work is the exposure of what goes into
making the import statement work.  That means the various importers that
were once implicit are now fully exposed as part of the *note importlib:
77. package.

The abstract base classes defined in *note importlib.abc: 78. have been
expanded to properly delineate between *note meta path finders: 10ae.
and *note path entry finders: 10af. by introducing *note
importlib.abc.MetaPathFinder: 875. and *note
importlib.abc.PathEntryFinder: 876, respectively.  The old ABC of
‘importlib.abc.Finder’ is now only provided for backwards-compatibility
and does not enforce any method requirements.

In terms of finders, *note importlib.machinery.FileFinder: 10b0. exposes
the mechanism used to search for source and bytecode files of a module.
Previously this class was an implicit member of *note sys.path_hooks:
105f.

For loaders, the new abstract base class *note importlib.abc.FileLoader:
10b1. helps write a loader that uses the file system as the storage
mechanism for a module’s code.  The loader for source files (*note
importlib.machinery.SourceFileLoader: 10b2.), sourceless bytecode files
(*note importlib.machinery.SourcelessFileLoader: 10b3.), and extension
modules (*note importlib.machinery.ExtensionFileLoader: cd6.) are now
available for direct use.

*note ImportError: 41c. now has ‘name’ and ‘path’ attributes which are
set when there is relevant data to provide.  The message for failed
imports will also provide the full name of the module now instead of
just the tail end of the module’s name.

The *note importlib.invalidate_caches(): c30. function will now call the
method with the same name on all finders cached in *note
sys.path_importer_cache: 5e7. to help clean up any stored state as
necessary.


File: python.info,  Node: Visible Changes,  Prev: New APIs,  Up: Using importlib as the Implementation of Import

1.11.15.2 Visible Changes
.........................

For potential required changes to code, see the *note Porting Python
code: 10ac. section.

Beyond the expanse of what *note importlib: 77. now exposes, there are
other visible changes to import.  The biggest is that *note
sys.meta_path: d53. and *note sys.path_hooks: 105f. now store all of the
meta path finders and path entry hooks used by import.  Previously the
finders were implicit and hidden within the C code of import instead of
being directly exposed.  This means that one can now easily remove or
change the order of the various finders to fit one’s needs.

Another change is that all modules have a ‘__loader__’ attribute,
storing the loader used to create the module.  PEP 302(1) has been
updated to make this attribute mandatory for loaders to implement, so in
the future once 3rd-party loaders have been updated people will be able
to rely on the existence of the attribute.  Until such time, though,
import is setting the module post-load.

Loaders are also now expected to set the ‘__package__’ attribute from
PEP 366(2).  Once again, import itself is already setting this on all
loaders from *note importlib: 77. and import itself is setting the
attribute post-load.

‘None’ is now inserted into *note sys.path_importer_cache: 5e7. when no
finder can be found on *note sys.path_hooks: 105f.  Since
‘imp.NullImporter’ is not directly exposed on ‘sys.path_hooks’ it could
no longer be relied upon to always be available to use as a value
representing no finder found.

All other changes relate to semantic changes which should be taken into
consideration when updating code for Python 3.3, and thus should be read
about in the *note Porting Python code: 10ac. section of this document.

(Implementation by Brett Cannon)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0302/

   (2) https://peps.python.org/pep-0366/


File: python.info,  Node: Other Language Changes<11>,  Next: A Finer-Grained Import Lock,  Prev: Using importlib as the Implementation of Import,  Up: What’s New In Python 3 3

1.11.16 Other Language Changes
------------------------------

Some smaller changes made to the core Python language are:

   * Added support for Unicode name aliases and named sequences.  Both
     *note unicodedata.lookup(): 10b6. and ‘'\N{...}'’ now resolve name
     aliases, and ‘unicodedata.lookup()’ resolves named sequences too.

     (Contributed by Ezio Melotti in bpo-12753(1).)

   * Unicode database updated to UCD version 6.1.0

   * Equality comparisons on *note range(): 94d. objects now return a
     result reflecting the equality of the underlying sequences
     generated by those range objects.  (bpo-13201(2))

   * The ‘count()’, ‘find()’, ‘rfind()’, ‘index()’ and ‘rindex()’
     methods of *note bytes: 1c2. and *note bytearray: 2ea. objects now
     accept an integer between 0 and 255 as their first argument.

     (Contributed by Petri Lehtinen in bpo-12170(3).)

   * The ‘rjust()’, ‘ljust()’, and ‘center()’ methods of *note bytes:
     1c2. and *note bytearray: 2ea. now accept a ‘bytearray’ for the
     ‘fill’ argument.  (Contributed by Petri Lehtinen in bpo-12380(4).)

   * New methods have been added to *note list: 614. and *note
     bytearray: 2ea.: ‘copy()’ and ‘clear()’ (bpo-10516(5)).
     Consequently, *note MutableSequence: 1a1. now also defines a
     ‘clear()’ method (bpo-11388(6)).

   * Raw bytes literals can now be written ‘rb"..."’ as well as
     ‘br"..."’.

     (Contributed by Antoine Pitrou in bpo-13748(7).)

   * *note dict.setdefault(): 10b7. now does only one lookup for the
     given key, making it atomic when used with built-in types.

     (Contributed by Filip Gruszczyński in bpo-13521(8).)

   * The error messages produced when a function call does not match the
     function signature have been significantly improved.

     (Contributed by Benjamin Peterson.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12753

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13201

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12170

   (4) https://bugs.python.org/issue?@action=redirect&bpo=12380

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10516

   (6) https://bugs.python.org/issue?@action=redirect&bpo=11388

   (7) https://bugs.python.org/issue?@action=redirect&bpo=13748

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13521


File: python.info,  Node: A Finer-Grained Import Lock,  Next: Builtin functions and types,  Prev: Other Language Changes<11>,  Up: What’s New In Python 3 3

1.11.17 A Finer-Grained Import Lock
-----------------------------------

Previous versions of CPython have always relied on a global import lock.
This led to unexpected annoyances, such as deadlocks when importing a
module would trigger code execution in a different thread as a
side-effect.  Clumsy workarounds were sometimes employed, such as the
*note PyImport_ImportModuleNoBlock(): 3c0. C API function.

In Python 3.3, importing a module takes a per-module lock.  This
correctly serializes importation of a given module from multiple threads
(preventing the exposure of incompletely initialized modules), while
eliminating the aforementioned annoyances.

(Contributed by Antoine Pitrou in bpo-9260(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9260


File: python.info,  Node: Builtin functions and types,  Next: New Modules<11>,  Prev: A Finer-Grained Import Lock,  Up: What’s New In Python 3 3

1.11.18 Builtin functions and types
-----------------------------------

   * *note open(): 51f. gets a new 'opener' parameter: the underlying
     file descriptor for the file object is then obtained by calling
     'opener' with ('file', 'flags').  It can be used to use custom
     flags like *note os.O_CLOEXEC: 10ba. for example.  The ‘'x'’ mode
     was added: open for exclusive creation, failing if the file already
     exists.

   * *note print(): fae.: added the 'flush' keyword argument.  If the
     'flush' keyword argument is true, the stream is forcibly flushed.

   * *note hash(): 5ee.: hash randomization is enabled by default, see
     *note object.__hash__(): b14. and *note PYTHONHASHSEED: 10bb.

   * The *note str: 44f. type gets a new *note casefold(): e06. method:
     return a casefolded copy of the string, casefolded strings may be
     used for caseless matching.  For example, ‘'ß'.casefold()’ returns
     ‘'ss'’.

   * The sequence documentation has been substantially rewritten to
     better explain the binary/text sequence distinction and to provide
     specific documentation sections for the individual builtin sequence
     types (bpo-4966(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4966


File: python.info,  Node: New Modules<11>,  Next: Improved Modules<11>,  Prev: Builtin functions and types,  Up: What’s New In Python 3 3

1.11.19 New Modules
-------------------

* Menu:

* faulthandler: faulthandler<4>.
* ipaddress: ipaddress<6>.
* lzma: lzma<2>.


File: python.info,  Node: faulthandler<4>,  Next: ipaddress<6>,  Up: New Modules<11>

1.11.19.1 faulthandler
......................

This new debug module *note faulthandler: 58. contains functions to dump
Python tracebacks explicitly, on a fault (a crash like a segmentation
fault), after a timeout, or on a user signal.  Call *note
faulthandler.enable(): cc4. to install fault handlers for the *note
SIGSEGV: 10be, *note SIGFPE: 10bf, *note SIGABRT: 10c0, *note SIGBUS:
10c1, and *note SIGILL: 10c2. signals.  You can also enable them at
startup by setting the *note PYTHONFAULTHANDLER: 10c3. environment
variable or by using *note -X: 176. ‘faulthandler’ command line option.

Example of a segmentation fault on Linux:

     $ python -q -X faulthandler
     >>> import ctypes
     >>> ctypes.string_at(0)
     Fatal Python error: Segmentation fault

     Current thread 0x00007fb899f39700:
       File "/home/python/cpython/Lib/ctypes/__init__.py", line 486 in string_at
       File "<stdin>", line 1 in <module>
     Segmentation fault


File: python.info,  Node: ipaddress<6>,  Next: lzma<2>,  Prev: faulthandler<4>,  Up: New Modules<11>

1.11.19.2 ipaddress
...................

The new *note ipaddress: 80. module provides tools for creating and
manipulating objects representing IPv4 and IPv6 addresses, networks and
interfaces (i.e.  an IP address associated with a specific IP subnet).

(Contributed by Google and Peter Moody in PEP 3144(1).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3144/


File: python.info,  Node: lzma<2>,  Prev: ipaddress<6>,  Up: New Modules<11>

1.11.19.3 lzma
..............

The newly added *note lzma: 8a. module provides data compression and
decompression using the LZMA algorithm, including support for the ‘.xz’
and ‘.lzma’ file formats.

(Contributed by Nadeem Vawda and Per Øyvind Karlsen in bpo-6715(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6715


File: python.info,  Node: Improved Modules<11>,  Next: Optimizations<10>,  Prev: New Modules<11>,  Up: What’s New In Python 3 3

1.11.20 Improved Modules
------------------------

* Menu:

* abc: abc<2>.
* array: array<5>.
* base64: base64<4>.
* binascii: binascii<3>.
* bz2: bz2<2>.
* codecs: codecs<2>.
* collections: collections<7>.
* contextlib: contextlib<7>.
* crypt: crypt<2>.
* curses: curses<5>.
* datetime: datetime<6>.
* decimal: decimal<3>.
* email: email<5>.
* ftplib: ftplib<3>.
* functools: functools<6>.
* gc: gc<6>.
* hmac: hmac<4>.
* http: http<4>.
* html: html<2>.
* imaplib: imaplib<3>.
* inspect: inspect<9>.
* io: io<6>.
* itertools: itertools<6>.
* logging: logging<7>.
* math: math<9>.
* mmap: mmap<4>.
* multiprocessing: multiprocessing<8>.
* nntplib: nntplib<2>.
* os: os<12>.
* pdb: pdb<7>.
* pickle: pickle<5>.
* pydoc: pydoc<5>.
* re: re<9>.
* sched::
* select: select<2>.
* shlex: shlex<3>.
* shutil: shutil<7>.
* signal: signal<4>.
* smtpd: smtpd<4>.
* smtplib: smtplib<4>.
* socket: socket<10>.
* socketserver: socketserver<3>.
* sqlite3: sqlite3<10>.
* ssl: ssl<11>.
* stat: stat<2>.
* struct: struct<3>.
* subprocess: subprocess<6>.
* sys: sys<13>.
* tarfile: tarfile<9>.
* tempfile: tempfile<4>.
* textwrap: textwrap<2>.
* threading: threading<8>.
* time: time<8>.
* types: types<7>.
* unittest: unittest<10>.
* urllib: urllib<4>.
* webbrowser: webbrowser<3>.
* xml.etree.ElementTree: xml etree ElementTree<2>.
* zlib: zlib<2>.


File: python.info,  Node: abc<2>,  Next: array<5>,  Up: Improved Modules<11>

1.11.20.1 abc
.............

Improved support for abstract base classes containing descriptors
composed with abstract methods.  The recommended approach to declaring
abstract descriptors is now to provide ‘__isabstractmethod__’ as a
dynamically updated property.  The built-in descriptors have been
updated accordingly.

   * *note abc.abstractproperty: 10c8. has been deprecated, use *note
     property: 194. with *note abc.abstractmethod(): 10c9. instead.

   * *note abc.abstractclassmethod: 10ca. has been deprecated, use *note
     classmethod: 166. with *note abc.abstractmethod(): 10c9. instead.

   * *note abc.abstractstaticmethod: 10cb. has been deprecated, use
     *note staticmethod: 419. with *note abc.abstractmethod(): 10c9.
     instead.

(Contributed by Darren Dale in bpo-11610(1).)

*note abc.ABCMeta.register(): 10cc. now returns the registered subclass,
which means it can now be used as a class decorator (bpo-10868(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11610

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10868


File: python.info,  Node: array<5>,  Next: base64<4>,  Prev: abc<2>,  Up: Improved Modules<11>

1.11.20.2 array
...............

The *note array: 7. module supports the long long type using ‘q’ and ‘Q’
type codes.

(Contributed by Oren Tirosh and Hirokazu Yamamoto in bpo-1172711(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1172711


File: python.info,  Node: base64<4>,  Next: binascii<3>,  Prev: array<5>,  Up: Improved Modules<11>

1.11.20.3 base64
................

ASCII-only Unicode strings are now accepted by the decoding functions of
the *note base64: e. modern interface.  For example,
‘base64.b64decode('YWJj')’ returns ‘b'abc'’.  (Contributed by Catalin
Iacob in bpo-13641(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13641


File: python.info,  Node: binascii<3>,  Next: bz2<2>,  Prev: base64<4>,  Up: Improved Modules<11>

1.11.20.4 binascii
..................

In addition to the binary objects they normally accept, the ‘a2b_’
functions now all also accept ASCII-only strings as input.  (Contributed
by Antoine Pitrou in bpo-13637(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13637


File: python.info,  Node: bz2<2>,  Next: codecs<2>,  Prev: binascii<3>,  Up: Improved Modules<11>

1.11.20.5 bz2
.............

The *note bz2: 13. module has been rewritten from scratch.  In the
process, several new features have been added:

   * New *note bz2.open(): 10d1. function: open a bzip2-compressed file
     in binary or text mode.

   * *note bz2.BZ2File: 86d. can now read from and write to arbitrary
     file-like objects, by means of its constructor’s 'fileobj'
     argument.

     (Contributed by Nadeem Vawda in bpo-5863(1).)

   * *note bz2.BZ2File: 86d. and *note bz2.decompress(): 10d2. can now
     decompress multi-stream inputs (such as those produced by the
     ‘pbzip2’ tool).  ‘bz2.BZ2File’ can now also be used to create this
     type of file, using the ‘'a'’ (append) mode.

     (Contributed by Nir Aides in bpo-1625(2).)

   * *note bz2.BZ2File: 86d. now implements all of the *note
     io.BufferedIOBase: 697. API, except for the ‘detach()’ and
     ‘truncate()’ methods.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5863

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1625


File: python.info,  Node: codecs<2>,  Next: collections<7>,  Prev: bz2<2>,  Up: Improved Modules<11>

1.11.20.6 codecs
................

The *note mbcs: 53. codec has been rewritten to handle correctly
‘replace’ and ‘ignore’ error handlers on all Windows versions.  The
‘mbcs’ codec now supports all error handlers, instead of only ‘replace’
to encode and ‘ignore’ to decode.

A new Windows-only codec has been added: ‘cp65001’ (bpo-13216(1)).  It
is the Windows code page 65001 (Windows UTF-8, ‘CP_UTF8’).  For example,
it is used by ‘sys.stdout’ if the console output code page is set to
cp65001 (e.g., using ‘chcp 65001’ command).

Multibyte CJK decoders now resynchronize faster.  They only ignore the
first byte of an invalid byte sequence.  For example,
‘b'\xff\n'.decode('gb2312', 'replace')’ now returns a ‘\n’ after the
replacement character.

(bpo-12016(2))

Incremental CJK codec encoders are no longer reset at each call to their
encode() methods.  For example:

     >>> import codecs
     >>> encoder = codecs.getincrementalencoder('hz')('strict')
     >>> b''.join(encoder.encode(x) for x in '\u52ff\u65bd\u65bc\u4eba\u3002 Bye.')
     b'~{NpJ)l6HK!#~} Bye.'

This example gives ‘b'~{Np~}~{J)~}~{l6~}~{HK~}~{!#~} Bye.'’ with older
Python versions.

(bpo-12100(3))

The ‘unicode_internal’ codec has been deprecated.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13216

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12016

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12100


File: python.info,  Node: collections<7>,  Next: contextlib<7>,  Prev: codecs<2>,  Up: Improved Modules<11>

1.11.20.7 collections
.....................

Addition of a new *note ChainMap: c3c. class to allow treating a number
of mappings as a single unit.  (Written by Raymond Hettinger for
bpo-11089(1), made public in bpo-11297(2).)

The abstract base classes have been moved in a new *note
collections.abc: 1e. module, to better differentiate between the
abstract and the concrete collections classes.  Aliases for ABCs are
still present in the *note collections: 1d. module to preserve existing
imports.  (bpo-11085(3))

The *note Counter: 10d5. class now supports the unary ‘+’ and ‘-’
operators, as well as the in-place operators ‘+=’, ‘-=’, ‘|=’, and ‘&=’.
(Contributed by Raymond Hettinger in bpo-13121(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11089

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11297

   (3) https://bugs.python.org/issue?@action=redirect&bpo=11085

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13121


File: python.info,  Node: contextlib<7>,  Next: crypt<2>,  Prev: collections<7>,  Up: Improved Modules<11>

1.11.20.8 contextlib
....................

*note ExitStack: b41. now provides a solid foundation for programmatic
manipulation of context managers and similar cleanup functionality.
Unlike the previous ‘contextlib.nested’ API (which was deprecated and
removed), the new API is designed to work correctly regardless of
whether context managers acquire their resources in their ‘__init__’
method (for example, file objects) or in their ‘__enter__’ method (for
example, synchronisation objects from the *note threading: ed. module).

(bpo-13585(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13585


File: python.info,  Node: crypt<2>,  Next: curses<5>,  Prev: contextlib<7>,  Up: Improved Modules<11>

1.11.20.9 crypt
...............

Addition of salt and modular crypt format (hashing method) and the
‘mksalt()’ function to the ‘crypt’ module.

(bpo-10924(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10924


File: python.info,  Node: curses<5>,  Next: datetime<6>,  Prev: crypt<2>,  Up: Improved Modules<11>

1.11.20.10 curses
.................

   * If the *note curses: 2b. module is linked to the ncursesw library,
     use Unicode functions when Unicode strings or characters are passed
     (e.g.  ‘waddwstr()’), and bytes functions otherwise (e.g.
     ‘waddstr()’).

   * Use the locale encoding instead of ‘utf-8’ to encode Unicode
     strings.

   * *note curses.window: 10d9. has a new *note curses.window.encoding:
     10da. attribute.

   * The *note curses.window: 10d9. class has a new *note get_wch():
     10db. method to get a wide character

   * The *note curses: 2b. module has a new *note unget_wch(): 10dc.
     function to push a wide character so the next *note get_wch():
     10db. will return it

(Contributed by Iñigo Serna in bpo-6755(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6755


File: python.info,  Node: datetime<6>,  Next: decimal<3>,  Prev: curses<5>,  Up: Improved Modules<11>

1.11.20.11 datetime
...................

   * Equality comparisons between naive and aware *note datetime: 1cc.
     instances now return *note False: b4f. instead of raising *note
     TypeError: 2c3. (bpo-15006(1)).

   * New *note datetime.datetime.timestamp(): 10de. method: Return POSIX
     timestamp corresponding to the *note datetime: 1cc. instance.

   * The *note datetime.datetime.strftime(): cb5. method supports
     formatting years older than 1000.

   * The *note datetime.datetime.astimezone(): 9db. method can now be
     called without arguments to convert datetime instance to the system
     timezone.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15006


File: python.info,  Node: decimal<3>,  Next: email<5>,  Prev: datetime<6>,  Up: Improved Modules<11>

1.11.20.12 decimal
..................

bpo-7652(1) - integrate fast native decimal arithmetic.

     C-module and libmpdec written by Stefan Krah.

The new C version of the decimal module integrates the high speed
libmpdec library for arbitrary precision correctly rounded decimal
floating-point arithmetic.  libmpdec conforms to IBM’s General Decimal
Arithmetic Specification.

Performance gains range from 10x for database applications to 100x for
numerically intensive applications.  These numbers are expected gains
for standard precisions used in decimal floating-point arithmetic.
Since the precision is user configurable, the exact figures may vary.
For example, in integer bignum arithmetic the differences can be
significantly higher.

The following table is meant as an illustration.  Benchmarks are
available at ‘https://www.bytereef.org/mpdecimal/quickstart.html’.

                   decimal.py        _decimal           speedup
                                                        
     ---------------------------------------------------------------------
                                                        
     pi            42.02s            0.345s             120x
                                                        
                                                        
     telco         172.19s           5.68s              30x
                                                        
                                                        
     psycopg       3.57s             0.29s              12x
                                                        

* Menu:

* Features: Features<2>.
* API changes: API changes<2>.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7652


File: python.info,  Node: Features<2>,  Next: API changes<2>,  Up: decimal<3>

1.11.20.13 Features
...................

   * The *note FloatOperation: 10e1. signal optionally enables stricter
     semantics for mixing floats and Decimals.

   * If Python is compiled without threads, the C version automatically
     disables the expensive thread local context machinery.  In this
     case, the variable *note HAVE_THREADS: 10e2. is set to ‘False’.


File: python.info,  Node: API changes<2>,  Prev: Features<2>,  Up: decimal<3>

1.11.20.14 API changes
......................

   * The C module has the following context limits, depending on the
     machine architecture:

                                           32-bit               64-bit
                                                                
          ------------------------------------------------------------------------------------
                                                                
          *note MAX_PREC: 10e4.            ‘425000000’          ‘999999999999999999’
                                                                
                                                                
          *note MAX_EMAX: 10e5.            ‘425000000’          ‘999999999999999999’
                                                                
                                                                
          *note MIN_EMIN: 10e6.            ‘-425000000’         ‘-999999999999999999’
                                                                

   * In the context templates (*note DefaultContext: 10e7, *note
     BasicContext: 10e8. and *note ExtendedContext: 10e9.) the magnitude
     of *note Emax: 10ea. and *note Emin: 10eb. has changed to ‘999999’.

   * The *note Decimal: 29d. constructor in decimal.py does not observe
     the context limits and converts values with arbitrary exponents or
     precision exactly.  Since the C version has internal limits, the
     following scheme is used: If possible, values are converted
     exactly, otherwise *note InvalidOperation: 10ec. is raised and the
     result is NaN. In the latter case it is always possible to use
     *note create_decimal(): 10ed. in order to obtain a rounded or
     inexact value.

   * The power function in decimal.py is always correctly rounded.  In
     the C version, it is defined in terms of the correctly rounded
     *note exp(): 10ee. and *note ln(): 10ef. functions, but the final
     result is only “almost always correctly rounded”.

   * In the C version, the context dictionary containing the signals is
     a *note MutableMapping: 10f0.  For speed reasons, *note flags:
     10f1. and *note traps: 10f2. always refer to the same
     ‘MutableMapping’ that the context was initialized with.  If a new
     signal dictionary is assigned, ‘flags’ and ‘traps’ are updated with
     the new values, but they do not reference the RHS dictionary.

   * Pickling a *note Context: 10f3. produces a different output in
     order to have a common interchange format for the Python and C
     versions.

   * The order of arguments in the *note Context: 10f3. constructor has
     been changed to match the order displayed by *note repr(): 803.

   * The ‘watchexp’ parameter in the *note quantize(): 10f4. method is
     deprecated.


File: python.info,  Node: email<5>,  Next: ftplib<3>,  Prev: decimal<3>,  Up: Improved Modules<11>

1.11.20.15 email
................

* Menu:

* Policy Framework::
* Provisional Policy with New Header API::
* Other API Changes::


File: python.info,  Node: Policy Framework,  Next: Provisional Policy with New Header API,  Up: email<5>

1.11.20.16 Policy Framework
...........................

The email package now has a *note policy: 4f. framework.  A *note
Policy: 10f7. is an object with several methods and properties that
control how the email package behaves.  The primary policy for Python
3.3 is the *note Compat32: 10f8. policy, which provides backward
compatibility with the email package in Python 3.2.  A ‘policy’ can be
specified when an email message is parsed by a *note parser: 4e, or when
a *note Message: 27c. object is created, or when an email is serialized
using a *note generator: 40.  Unless overridden, a policy passed to a
‘parser’ is inherited by all the ‘Message’ object and sub-objects
created by the ‘parser’.  By default a ‘generator’ will use the policy
of the ‘Message’ object it is serializing.  The default policy is *note
compat32: cbe.

The minimum set of controls implemented by all ‘policy’ objects are:

max_line_length     The maximum length, excluding the linesep character(s),
                    individual lines may have when a ‘Message’ is serialized.
                    Defaults to 78.
                    
                    
linesep             The character used to separate individual lines when a
                    ‘Message’ is serialized.  Defaults to ‘\n’.
                    
                    
cte_type            ‘7bit’ or ‘8bit’.  ‘8bit’ applies only to a ‘Bytes’
                    ‘generator’, and means that non-ASCII may be used where
                    allowed by the protocol (or where it exists in the
                    original input).
                    
                    
raise_on_defect     Causes a ‘parser’ to raise error when defects are
                    encountered instead of adding them to the ‘Message’
                    object’s ‘defects’ list.
                    

A new policy instance, with new settings, is created using the *note
clone(): 10f9. method of policy objects.  ‘clone’ takes any of the above
controls as keyword arguments.  Any control not specified in the call
retains its default value.  Thus you can create a policy that uses
‘\r\n’ linesep characters like this:

     mypolicy = compat32.clone(linesep='\r\n')

Policies can be used to make the generation of messages in the format
needed by your application simpler.  Instead of having to remember to
specify ‘linesep='\r\n'’ in all the places you call a ‘generator’, you
can specify it once, when you set the policy used by the ‘parser’ or the
‘Message’, whichever your program uses to create ‘Message’ objects.  On
the other hand, if you need to generate messages in multiple forms, you
can still specify the parameters in the appropriate ‘generator’ call.
Or you can have custom policy instances for your different cases, and
pass those in when you create the ‘generator’.


File: python.info,  Node: Provisional Policy with New Header API,  Next: Other API Changes,  Prev: Policy Framework,  Up: email<5>

1.11.20.17 Provisional Policy with New Header API
.................................................

While the policy framework is worthwhile all by itself, the main
motivation for introducing it is to allow the creation of new policies
that implement new features for the email package in a way that
maintains backward compatibility for those who do not use the new
policies.  Because the new policies introduce a new API, we are
releasing them in Python 3.3 as a *note provisional policy: 107f.
Backwards incompatible changes (up to and including removal of the code)
may occur if deemed necessary by the core developers.

The new policies are instances of *note EmailPolicy: 10fb, and add the
following additional controls:

refold_source       Controls whether or not headers parsed by a
                    *note parser: 4e. are refolded by the
                    *note generator: 40.  It can be ‘none’, ‘long’, or ‘all’.
                    The default is ‘long’, which means that source headers
                    with a line longer than ‘max_line_length’ get refolded.
                    ‘none’ means no line get refolded, and ‘all’ means that
                    all lines get refolded.
                    
                    
header_factory      A callable that take a ‘name’ and ‘value’ and produces a
                    custom header object.
                    

The ‘header_factory’ is the key to the new features provided by the new
policies.  When one of the new policies is used, any header retrieved
from a ‘Message’ object is an object produced by the ‘header_factory’,
and any time you set a header on a ‘Message’ it becomes an object
produced by ‘header_factory’.  All such header objects have a ‘name’
attribute equal to the header name.  Address and Date headers have
additional attributes that give you access to the parsed data of the
header.  This means you can now do things like this:

     >>> m = Message(policy=SMTP)
     >>> m['To'] = 'Éric <foo@example.com>'
     >>> m['to']
     'Éric <foo@example.com>'
     >>> m['to'].addresses
     (Address(display_name='Éric', username='foo', domain='example.com'),)
     >>> m['to'].addresses[0].username
     'foo'
     >>> m['to'].addresses[0].display_name
     'Éric'
     >>> m['Date'] = email.utils.localtime()
     >>> m['Date'].datetime
     datetime.datetime(2012, 5, 25, 21, 39, 24, 465484, tzinfo=datetime.timezone(datetime.timedelta(-1, 72000), 'EDT'))
     >>> m['Date']
     'Fri, 25 May 2012 21:44:27 -0400'
     >>> print(m)
     To: =?utf-8?q?=C3=89ric?= <foo@example.com>
     Date: Fri, 25 May 2012 21:44:27 -0400

You will note that the unicode display name is automatically encoded as
‘utf-8’ when the message is serialized, but that when the header is
accessed directly, you get the unicode version.  This eliminates any
need to deal with the *note email.header: 41. *note decode_header():
10fc. or *note make_header(): 10fd. functions.

You can also create addresses from parts:

     >>> m['cc'] = [Group('pals', [Address('Bob', 'bob', 'example.com'),
     ...                           Address('Sally', 'sally', 'example.com')]),
     ...            Address('Bonzo', addr_spec='bonz@laugh.com')]
     >>> print(m)
     To: =?utf-8?q?=C3=89ric?= <foo@example.com>
     Date: Fri, 25 May 2012 21:44:27 -0400
     cc: pals: Bob <bob@example.com>, Sally <sally@example.com>;, Bonzo <bonz@laugh.com>

Decoding to unicode is done automatically:

     >>> m2 = message_from_string(str(m))
     >>> m2['to']
     'Éric <foo@example.com>'

When you parse a message, you can use the ‘addresses’ and ‘groups’
attributes of the header objects to access the groups and individual
addresses:

     >>> m2['cc'].addresses
     (Address(display_name='Bob', username='bob', domain='example.com'), Address(display_name='Sally', username='sally', domain='example.com'), Address(display_name='Bonzo', username='bonz', domain='laugh.com'))
     >>> m2['cc'].groups
     (Group(display_name='pals', addresses=(Address(display_name='Bob', username='bob', domain='example.com'), Address(display_name='Sally', username='sally', domain='example.com')), Group(display_name=None, addresses=(Address(display_name='Bonzo', username='bonz', domain='laugh.com'),))

In summary, if you use one of the new policies, header manipulation
works the way it ought to: your application works with unicode strings,
and the email package transparently encodes and decodes the unicode to
and from the RFC standard Content Transfer Encodings.


File: python.info,  Node: Other API Changes,  Prev: Provisional Policy with New Header API,  Up: email<5>

1.11.20.18 Other API Changes
............................

New *note BytesHeaderParser: 10ff, added to the *note parser: 4e. module
to complement *note HeaderParser: 1100. and complete the Bytes API.

New utility functions:

   * *note format_datetime(): 1101.: given a *note datetime: 1cc,
     produce a string formatted for use in an email header.

   * *note parsedate_to_datetime(): 1102.: given a date string from an
     email header, convert it into an aware *note datetime: 1cc, or a
     naive ‘datetime’ if the offset is ‘-0000’.

   * *note localtime(): 2c4.: With no argument, returns the current
     local time as an aware *note datetime: 1cc. using the local *note
     timezone: 1103.  Given an aware ‘datetime’, converts it into an
     aware ‘datetime’ using the local ‘timezone’.


File: python.info,  Node: ftplib<3>,  Next: functools<6>,  Prev: email<5>,  Up: Improved Modules<11>

1.11.20.19 ftplib
.................

   * *note ftplib.FTP: 903. now accepts a ‘source_address’ keyword
     argument to specify the ‘(host, port)’ to use as the source address
     in the bind call when creating the outgoing socket.  (Contributed
     by Giampaolo Rodolà in bpo-8594(1).)

   * The *note FTP_TLS: 904. class now provides a new *note ccc(): 1105.
     function to revert control channel back to plaintext.  This can be
     useful to take advantage of firewalls that know how to handle NAT
     with non-secure FTP without opening fixed ports.  (Contributed by
     Giampaolo Rodolà in bpo-12139(2).)

   * Added *note ftplib.FTP.mlsd(): 1106. method which provides a
     parsable directory listing format and deprecates *note
     ftplib.FTP.nlst(): 1107. and *note ftplib.FTP.dir(): 1108.
     (Contributed by Giampaolo Rodolà in bpo-11072(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8594

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12139

   (3) https://bugs.python.org/issue?@action=redirect&bpo=11072


File: python.info,  Node: functools<6>,  Next: gc<6>,  Prev: ftplib<3>,  Up: Improved Modules<11>

1.11.20.20 functools
....................

The *note functools.lru_cache(): 9fa. decorator now accepts a ‘typed’
keyword argument (that defaults to ‘False’ to ensure that it caches
values of different types that compare equal in separate cache slots.
(Contributed by Raymond Hettinger in bpo-13227(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13227


File: python.info,  Node: gc<6>,  Next: hmac<4>,  Prev: functools<6>,  Up: Improved Modules<11>

1.11.20.21 gc
.............

It is now possible to register callbacks invoked by the garbage
collector before and after collection using the new *note callbacks:
110b. list.


File: python.info,  Node: hmac<4>,  Next: http<4>,  Prev: gc<6>,  Up: Improved Modules<11>

1.11.20.22 hmac
...............

A new *note compare_digest(): 110d. function has been added to prevent
side channel attacks on digests through timing analysis.  (Contributed
by Nick Coghlan and Christian Heimes in bpo-15061(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15061


File: python.info,  Node: http<4>,  Next: html<2>,  Prev: hmac<4>,  Up: Improved Modules<11>

1.11.20.23 http
...............

*note http.server.BaseHTTPRequestHandler: 110f. now buffers the headers
and writes them all at once when *note end_headers(): 1110. is called.
A new method *note flush_headers(): 1111. can be used to directly manage
when the accumulated headers are sent.  (Contributed by Andrew Schaaf in
bpo-3709(1).)

*note http.server: 72. now produces valid ‘HTML 4.01 strict’ output.
(Contributed by Ezio Melotti in bpo-13295(2).)

*note http.client.HTTPResponse: 1112. now has a *note readinto(): 1113.
method, which means it can be used as an *note io.RawIOBase: 1114.
class.  (Contributed by John Kuhn in bpo-13464(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3709

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13295

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13464


File: python.info,  Node: html<2>,  Next: imaplib<3>,  Prev: http<4>,  Up: Improved Modules<11>

1.11.20.24 html
...............

*note html.parser.HTMLParser: 87e. is now able to parse broken markup
without raising errors, therefore the 'strict' argument of the
constructor and the ‘HTMLParseError’ exception are now deprecated.  The
ability to parse broken markup is the result of a number of bug fixes
that are also available on the latest bug fix releases of Python
2.7/3.2.  (Contributed by Ezio Melotti in bpo-15114(1), and
bpo-14538(2), bpo-13993(3), bpo-13960(4), bpo-13358(5), bpo-1745761(6),
bpo-755670(7), bpo-13357(8), bpo-12629(9), bpo-1200313(10),
bpo-670664(11), bpo-13273(12), bpo-12888(13), bpo-7311(14).)

A new *note html5: 1116. dictionary that maps HTML5 named character
references to the equivalent Unicode character(s) (e.g.  ‘html5['gt;']
== '>'’) has been added to the *note html.entities: 6c. module.  The
dictionary is now also used by *note HTMLParser: 87e.  (Contributed by
Ezio Melotti in bpo-11113(15) and bpo-15156(16).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15114

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14538

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13993

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13960

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13358

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1745761

   (7) https://bugs.python.org/issue?@action=redirect&bpo=755670

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13357

   (9) https://bugs.python.org/issue?@action=redirect&bpo=12629

   (10) https://bugs.python.org/issue?@action=redirect&bpo=1200313

   (11) https://bugs.python.org/issue?@action=redirect&bpo=670664

   (12) https://bugs.python.org/issue?@action=redirect&bpo=13273

   (13) https://bugs.python.org/issue?@action=redirect&bpo=12888

   (14) https://bugs.python.org/issue?@action=redirect&bpo=7311

   (15) https://bugs.python.org/issue?@action=redirect&bpo=11113

   (16) https://bugs.python.org/issue?@action=redirect&bpo=15156


File: python.info,  Node: imaplib<3>,  Next: inspect<9>,  Prev: html<2>,  Up: Improved Modules<11>

1.11.20.25 imaplib
..................

The *note IMAP4_SSL: 90d. constructor now accepts an SSLContext
parameter to control parameters of the secure channel.

(Contributed by Sijin Joseph in bpo-8808(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8808


File: python.info,  Node: inspect<9>,  Next: io<6>,  Prev: imaplib<3>,  Up: Improved Modules<11>

1.11.20.26 inspect
..................

A new *note getclosurevars(): 1119. function has been added.  This
function reports the current binding of all names referenced from the
function body and where those names were resolved, making it easier to
verify correct internal state when testing code that relies on stateful
closures.

(Contributed by Meador Inge and Nick Coghlan in bpo-13062(1).)

A new *note getgeneratorlocals(): 111a. function has been added.  This
function reports the current binding of local variables in the
generator’s stack frame, making it easier to verify correct internal
state when testing generators.

(Contributed by Meador Inge in bpo-15153(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13062

   (2) https://bugs.python.org/issue?@action=redirect&bpo=15153


File: python.info,  Node: io<6>,  Next: itertools<6>,  Prev: inspect<9>,  Up: Improved Modules<11>

1.11.20.27 io
.............

The *note open(): 520. function has a new ‘'x'’ mode that can be used to
exclusively create a new file, and raise a *note FileExistsError: 105b.
if the file already exists.  It is based on the C11 ‘x’ mode to fopen().

(Contributed by David Townshend in bpo-12760(1).)

The constructor of the *note TextIOWrapper: 7bf. class has a new
'write_through' optional argument.  If 'write_through' is ‘True’, calls
to ‘write()’ are guaranteed not to be buffered: any data written on the
‘TextIOWrapper’ object is immediately handled to its underlying binary
buffer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12760


File: python.info,  Node: itertools<6>,  Next: logging<7>,  Prev: io<6>,  Up: Improved Modules<11>

1.11.20.28 itertools
....................

*note accumulate(): a08. now takes an optional ‘func’ argument for
providing a user-supplied binary function.


File: python.info,  Node: logging<7>,  Next: math<9>,  Prev: itertools<6>,  Up: Improved Modules<11>

1.11.20.29 logging
..................

The *note basicConfig(): a0b. function now supports an optional
‘handlers’ argument taking an iterable of handlers to be added to the
root logger.

A class level attribute ‘append_nul’ has been added to *note
SysLogHandler: 65f. to allow control of the appending of the ‘NUL’
(‘\000’) byte to syslog records, since for some daemons it is required
while for others it is passed through to the log.


File: python.info,  Node: math<9>,  Next: mmap<4>,  Prev: logging<7>,  Up: Improved Modules<11>

1.11.20.30 math
...............

The *note math: 8e. module has a new function, *note log2(): 111f, which
returns the base-2 logarithm of 'x'.

(Written by Mark Dickinson in bpo-11888(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11888


File: python.info,  Node: mmap<4>,  Next: multiprocessing<8>,  Prev: math<9>,  Up: Improved Modules<11>

1.11.20.31 mmap
...............

The *note read(): 1121. method is now more compatible with other
file-like objects: if the argument is omitted or specified as ‘None’, it
returns the bytes from the current file position to the end of the
mapping.  (Contributed by Petri Lehtinen in bpo-12021(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12021


File: python.info,  Node: multiprocessing<8>,  Next: nntplib<2>,  Prev: mmap<4>,  Up: Improved Modules<11>

1.11.20.32 multiprocessing
..........................

The new *note multiprocessing.connection.wait(): 1123. function allows
polling multiple objects (such as connections, sockets and pipes) with a
timeout.  (Contributed by Richard Oudkerk in bpo-12328(1).)

*note multiprocessing.connection.Connection: 1124. objects can now be
transferred over multiprocessing connections.  (Contributed by Richard
Oudkerk in bpo-4892(2).)

*note multiprocessing.Process: b75. now accepts a ‘daemon’ keyword
argument to override the default behavior of inheriting the ‘daemon’
flag from the parent process (bpo-6064(3)).

New attribute *note multiprocessing.Process.sentinel: 1125. allows a
program to wait on multiple *note Process: b75. objects at one time
using the appropriate OS primitives (for example, *note select: c1. on
posix systems).

New methods *note multiprocessing.pool.Pool.starmap(): 1126. and *note
starmap_async(): 1127. provide *note itertools.starmap(): 1128.
equivalents to the existing *note multiprocessing.pool.Pool.map(): 1129.
and *note map_async(): 112a. functions.  (Contributed by Hynek Schlawack
in bpo-12708(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12328

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4892

   (3) https://bugs.python.org/issue?@action=redirect&bpo=6064

   (4) https://bugs.python.org/issue?@action=redirect&bpo=12708


File: python.info,  Node: nntplib<2>,  Next: os<12>,  Prev: multiprocessing<8>,  Up: Improved Modules<11>

1.11.20.33 nntplib
..................

The ‘nntplib.NNTP’ class now supports the context management protocol to
unconditionally consume *note socket.error: 1093. exceptions and to
close the NNTP connection when done:

     >>> from nntplib import NNTP
     >>> with NNTP('news.gmane.org') as n:
     ...     n.group('gmane.comp.python.committers')
     ...
     ('211 1755 1 1755 gmane.comp.python.committers', 1755, 1, 1755, 'gmane.comp.python.committers')
     >>>

(Contributed by Giampaolo Rodolà in bpo-9795(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9795


File: python.info,  Node: os<12>,  Next: pdb<7>,  Prev: nntplib<2>,  Up: Improved Modules<11>

1.11.20.34 os
.............

   * The *note os: a1. module has a new *note pipe2(): 112d. function
     that makes it possible to create a pipe with *note O_CLOEXEC: 10ba.
     or *note O_NONBLOCK: e6e. flags set atomically.  This is especially
     useful to avoid race conditions in multi-threaded programs.

   * The *note os: a1. module has a new *note sendfile(): b28. function
     which provides an efficient “zero-copy” way for copying data from
     one file (or socket) descriptor to another.  The phrase “zero-copy”
     refers to the fact that all of the copying of data between the two
     descriptors is done entirely by the kernel, with no copying of data
     into userspace buffers.  ‘sendfile()’ can be used to efficiently
     copy data from a file on disk to a network socket, e.g.  for
     downloading a file.

     (Patch submitted by Ross Lagerwall and Giampaolo Rodolà in
     bpo-10882(1).)

   * To avoid race conditions like symlink attacks and issues with
     temporary files and directories, it is more reliable (and also
     faster) to manipulate file descriptors instead of file names.
     Python 3.3 enhances existing functions and introduces new functions
     to work on file descriptors (bpo-4761(2), bpo-10755(3) and
     bpo-14626(4)).

        - The *note os: a1. module has a new *note fwalk(): b77.
          function similar to *note walk(): 4ac. except that it also
          yields file descriptors referring to the directories visited.
          This is especially useful to avoid symlink races.

        - The following functions get new optional 'dir_fd' (*note paths
          relative to directory descriptors: 112e.) and/or
          'follow_symlinks' (*note not following symlinks: 112f.): *note
          access(): 1130, *note chflags(): 1131, *note chmod(): 21b,
          *note chown(): 1132, *note link(): 1133, *note lstat(): 4a4,
          *note mkdir(): 21d, *note mkfifo(): dbe, *note mknod(): dbf,
          *note open(): dc0, *note readlink(): 929, *note remove():
          1134, *note rename(): 1135, *note replace(): 1136, *note
          rmdir(): 1137, *note stat(): 4a3, *note symlink(): 1138, *note
          unlink(): 1139, *note utime(): 113a.  Platform support for
          using these parameters can be checked via the sets *note
          os.supports_dir_fd: 113b. and *note
          os.supports_follow_symlinks: 113c.

        - The following functions now support a file descriptor for
          their path argument: *note chdir(): 610, *note chmod(): 21b,
          *note chown(): 1132, *note execve(): 113d, *note listdir():
          113e, *note pathconf(): 113f, *note exists(): a1b, *note
          stat(): 4a3, *note statvfs(): 1140, *note utime(): 113a.
          Platform support for this can be checked via the *note
          os.supports_fd: 1141. set.

   * *note access(): 1130. accepts an ‘effective_ids’ keyword argument
     to turn on using the effective uid/gid rather than the real uid/gid
     in the access check.  Platform support for this can be checked via
     the *note supports_effective_ids: 1142. set.

   * The *note os: a1. module has two new functions: *note
     getpriority(): 1143. and *note setpriority(): 1144.  They can be
     used to get or set process niceness/priority in a fashion similar
     to *note os.nice(): 1145. but extended to all processes instead of
     just the current one.

     (Patch submitted by Giampaolo Rodolà in bpo-10784(5).)

   * The new *note os.replace(): 1136. function allows cross-platform
     renaming of a file with overwriting the destination.  With *note
     os.rename(): 1135, an existing destination file is overwritten
     under POSIX, but raises an error under Windows.  (Contributed by
     Antoine Pitrou in bpo-8828(6).)

   * The stat family of functions (*note stat(): 4a3, *note fstat():
     dba, and *note lstat(): 4a4.) now support reading a file’s
     timestamps with nanosecond precision.  Symmetrically, *note
     utime(): 113a. can now write file timestamps with nanosecond
     precision.  (Contributed by Larry Hastings in bpo-14127(7).)

   * The new *note os.get_terminal_size(): 1146. function queries the
     size of the terminal attached to a file descriptor.  See also *note
     shutil.get_terminal_size(): 1147.  (Contributed by Zbigniew
     Jędrzejewski-Szmek in bpo-13609(8).)

   * New functions to support Linux extended attributes (bpo-12720(9)):
     *note getxattr(): 1148, *note listxattr(): 1149, *note
     removexattr(): 114a, *note setxattr(): 114b.

   * New interface to the scheduler.  These functions control how a
     process is allocated CPU time by the operating system.  New
     functions: *note sched_get_priority_max(): 114c, *note
     sched_get_priority_min(): 114d, *note sched_getaffinity(): 114e,
     *note sched_getparam(): 114f, *note sched_getscheduler(): 1150,
     *note sched_rr_get_interval(): 1151, *note sched_setaffinity():
     1152, *note sched_setparam(): 1153, *note sched_setscheduler():
     1154, *note sched_yield(): 1155,

   * New functions to control the file system:

        * *note posix_fadvise(): dc1.: Announces an intention to access
          data in a specific pattern thus allowing the kernel to make
          optimizations.

        * *note posix_fallocate(): dc2.: Ensures that enough disk space
          is allocated for a file.

        * *note sync(): 1156.: Force write of everything to disk.

   * Additional new posix functions:

        * *note lockf(): 1157.: Apply, test or remove a POSIX lock on an
          open file descriptor.

        * *note pread(): b7b.: Read from a file descriptor at an offset,
          the file offset remains unchanged.

        * *note pwrite(): b7e.: Write to a file descriptor from an
          offset, leaving the file offset unchanged.

        * *note readv(): b7a.: Read from a file descriptor into a number
          of writable buffers.

        * *note truncate(): e6f.: Truncate the file corresponding to
          'path', so that it is at most 'length' bytes in size.

        * *note waitid(): dc7.: Wait for the completion of one or more
          child processes.

        * *note writev(): b7d.: Write the contents of 'buffers' to a
          file descriptor, where 'buffers' is an arbitrary sequence of
          buffers.

        * *note getgrouplist(): 1158. (bpo-9344(10)): Return list of
          group ids that specified user belongs to.

   * *note times(): 1159. and *note uname(): 115a.: Return type changed
     from a tuple to a tuple-like object with named attributes.

   * Some platforms now support additional constants for the *note
     lseek(): 115b. function, such as ‘os.SEEK_HOLE’ and ‘os.SEEK_DATA’.

   * New constants *note RTLD_LAZY: 115c, *note RTLD_NOW: 115d, *note
     RTLD_GLOBAL: 115e, *note RTLD_LOCAL: 115f, *note RTLD_NODELETE:
     1160, *note RTLD_NOLOAD: 1161, and *note RTLD_DEEPBIND: 1162. are
     available on platforms that support them.  These are for use with
     the *note sys.setdlopenflags(): 1163. function, and supersede the
     similar constants defined in *note ctypes: 2a. and ‘DLFCN’.
     (Contributed by Victor Stinner in bpo-13226(11).)

   * *note os.symlink(): 1138. now accepts (and ignores) the
     ‘target_is_directory’ keyword argument on non-Windows platforms, to
     ease cross-platform support.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10882

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4761

   (3) https://bugs.python.org/issue?@action=redirect&bpo=10755

   (4) https://bugs.python.org/issue?@action=redirect&bpo=14626

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10784

   (6) https://bugs.python.org/issue?@action=redirect&bpo=8828

   (7) https://bugs.python.org/issue?@action=redirect&bpo=14127

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13609

   (9) https://bugs.python.org/issue?@action=redirect&bpo=12720

   (10) https://bugs.python.org/issue?@action=redirect&bpo=9344

   (11) https://bugs.python.org/issue?@action=redirect&bpo=13226


File: python.info,  Node: pdb<7>,  Next: pickle<5>,  Prev: os<12>,  Up: Improved Modules<11>

1.11.20.35 pdb
..............

Tab-completion is now available not only for command names, but also
their arguments.  For example, for the ‘break’ command, function and
file names are completed.

(Contributed by Georg Brandl in bpo-14210(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14210


File: python.info,  Node: pickle<5>,  Next: pydoc<5>,  Prev: pdb<7>,  Up: Improved Modules<11>

1.11.20.36 pickle
.................

*note pickle.Pickler: a2b. objects now have an optional *note
dispatch_table: 1166. attribute allowing per-pickler reduction functions
to be set.

(Contributed by Richard Oudkerk in bpo-14166(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14166


File: python.info,  Node: pydoc<5>,  Next: re<9>,  Prev: pickle<5>,  Up: Improved Modules<11>

1.11.20.37 pydoc
................

The Tk GUI and the ‘serve()’ function have been removed from the *note
pydoc: b5. module: ‘pydoc -g’ and ‘serve()’ have been deprecated in
Python 3.2.


File: python.info,  Node: re<9>,  Next: sched,  Prev: pydoc<5>,  Up: Improved Modules<11>

1.11.20.38 re
.............

*note str: 44f. regular expressions now support ‘\u’ and ‘\U’ escapes.

(Contributed by Serhiy Storchaka in bpo-3665(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3665


File: python.info,  Node: sched,  Next: select<2>,  Prev: re<9>,  Up: Improved Modules<11>

1.11.20.39 sched
................

   * *note run(): 116a. now accepts a 'blocking' parameter which when
     set to false makes the method execute the scheduled events due to
     expire soonest (if any) and then return immediately.  This is
     useful in case you want to use the *note scheduler: 116b. in
     non-blocking applications.  (Contributed by Giampaolo Rodolà in
     bpo-13449(1).)

   * *note scheduler: 116b. class can now be safely used in
     multi-threaded environments.  (Contributed by Josiah Carlson and
     Giampaolo Rodolà in bpo-8684(2).)

   * 'timefunc' and 'delayfunct' parameters of *note scheduler: 116b.
     class constructor are now optional and defaults to *note
     time.time(): 254. and *note time.sleep(): 6a0. respectively.
     (Contributed by Chris Clark in bpo-13245(3).)

   * *note enter(): 116c. and *note enterabs(): 116d. 'argument'
     parameter is now optional.  (Contributed by Chris Clark in
     bpo-13245(4).)

   * *note enter(): 116c. and *note enterabs(): 116d. now accept a
     'kwargs' parameter.  (Contributed by Chris Clark in bpo-13245(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13449

   (2) https://bugs.python.org/issue?@action=redirect&bpo=8684

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13245

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13245

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13245


File: python.info,  Node: select<2>,  Next: shlex<3>,  Prev: sched,  Up: Improved Modules<11>

1.11.20.40 select
.................

Solaris and derivative platforms have a new class *note select.devpoll:
fcf. for high performance asynchronous sockets via ‘/dev/poll’.
(Contributed by Jesús Cea Avión in bpo-6397(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6397


File: python.info,  Node: shlex<3>,  Next: shutil<7>,  Prev: select<2>,  Up: Improved Modules<11>

1.11.20.41 shlex
................

The previously undocumented helper function ‘quote’ from the ‘pipes’
modules has been moved to the *note shlex: c4. module and documented.
*note quote(): 27d. properly escapes all characters in a string that
might be otherwise given special meaning by the shell.


File: python.info,  Node: shutil<7>,  Next: signal<4>,  Prev: shlex<3>,  Up: Improved Modules<11>

1.11.20.42 shutil
.................

   * New functions:

        * *note disk_usage(): 1171.: provides total, used and free disk
          space statistics.  (Contributed by Giampaolo Rodolà in
          bpo-12442(1).)

        * *note chown(): 240.: allows one to change user and/or group of
          the given path also specifying the user/group names and not
          only their numeric ids.  (Contributed by Sandro Tosi in
          bpo-12191(2).)

        * *note shutil.get_terminal_size(): 1147.: returns the size of
          the terminal window to which the interpreter is attached.
          (Contributed by Zbigniew Jędrzejewski-Szmek in bpo-13609(3).)

   * *note copy2(): a69. and *note copystat(): 1172. now preserve file
     timestamps with nanosecond precision on platforms that support it.
     They also preserve file “extended attributes” on Linux.
     (Contributed by Larry Hastings in bpo-14127(4) and bpo-15238(5).)

   * Several functions now take an optional ‘symlinks’ argument: when
     that parameter is true, symlinks aren’t dereferenced and the
     operation instead acts on the symlink itself (or creates one, if
     relevant).  (Contributed by Hynek Schlawack in bpo-12715(6).)

   * When copying files to a different file system, *note move(): a6a.
     now handles symlinks the way the posix ‘mv’ command does,
     recreating the symlink rather than copying the target file
     contents.  (Contributed by Jonathan Niehof in bpo-9993(7).)
     ‘move()’ now also returns the ‘dst’ argument as its result.

   * *note rmtree(): 301. is now resistant to symlink attacks on
     platforms which support the new ‘dir_fd’ parameter in *note
     os.open(): dc0. and *note os.unlink(): 1139.  (Contributed by
     Martin von Löwis and Hynek Schlawack in bpo-4489(8).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12442

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12191

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13609

   (4) https://bugs.python.org/issue?@action=redirect&bpo=14127

   (5) https://bugs.python.org/issue?@action=redirect&bpo=15238

   (6) https://bugs.python.org/issue?@action=redirect&bpo=12715

   (7) https://bugs.python.org/issue?@action=redirect&bpo=9993

   (8) https://bugs.python.org/issue?@action=redirect&bpo=4489


File: python.info,  Node: signal<4>,  Next: smtpd<4>,  Prev: shutil<7>,  Up: Improved Modules<11>

1.11.20.43 signal
.................

   * The *note signal: c6. module has new functions:

        * *note pthread_sigmask(): 1174.: fetch and/or change the signal
          mask of the calling thread (Contributed by Jean-Paul Calderone
          in bpo-8407(1));

        * *note pthread_kill(): 1175.: send a signal to a thread;

        * *note sigpending(): 1176.: examine pending functions;

        * *note sigwait(): 1177.: wait a signal;

        * *note sigwaitinfo(): dd9.: wait for a signal, returning
          detailed information about it;

        * *note sigtimedwait(): dd8.: like *note sigwaitinfo(): dd9. but
          with a timeout.

   * The signal handler writes the signal number as a single byte
     instead of a nul byte into the wakeup file descriptor.  So it is
     possible to wait more than one signal and know which signals were
     raised.

   * *note signal.signal(): 1178. and *note signal.siginterrupt(): 1179.
     raise an OSError, instead of a RuntimeError: OSError has an errno
     attribute.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8407


File: python.info,  Node: smtpd<4>,  Next: smtplib<4>,  Prev: signal<4>,  Up: Improved Modules<11>

1.11.20.44 smtpd
................

The ‘smtpd’ module now supports RFC 5321(1) (extended SMTP) and RFC
1870(2) (size extension).  Per the standard, these extensions are
enabled if and only if the client initiates the session with an ‘EHLO’
command.

(Initial ‘ELHO’ support by Alberto Trevino.  Size extension by Juhana
Jauhiainen.  Substantial additional work on the patch contributed by
Michele Orrù and Dan Boswell.  bpo-8739(3))

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5321.html

   (2) https://datatracker.ietf.org/doc/html/rfc1870.html

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8739


File: python.info,  Node: smtplib<4>,  Next: socket<10>,  Prev: smtpd<4>,  Up: Improved Modules<11>

1.11.20.45 smtplib
..................

The *note SMTP: 937, *note SMTP_SSL: 938, and *note LMTP: 939. classes
now accept a ‘source_address’ keyword argument to specify the ‘(host,
port)’ to use as the source address in the bind call when creating the
outgoing socket.  (Contributed by Paulo Scardine in bpo-11281(1).)

*note SMTP: 937. now supports the context management protocol, allowing
an ‘SMTP’ instance to be used in a ‘with’ statement.  (Contributed by
Giampaolo Rodolà in bpo-11289(2).)

The *note SMTP_SSL: 938. constructor and the *note starttls(): 117c.
method now accept an SSLContext parameter to control parameters of the
secure channel.  (Contributed by Kasun Herath in bpo-8809(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11281

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11289

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8809


File: python.info,  Node: socket<10>,  Next: socketserver<3>,  Prev: smtplib<4>,  Up: Improved Modules<11>

1.11.20.46 socket
.................

   * The *note socket: dcf. class now exposes additional methods to
     process ancillary data when supported by the underlying platform:

        * *note sendmsg(): 479.

        * *note recvmsg(): dd4.

        * *note recvmsg_into(): 117e.

     (Contributed by David Watson in bpo-6560(1), based on an earlier
     patch by Heiko Wundram)

   * The *note socket: dcf. class now supports the PF_CAN protocol
     family (‘https://en.wikipedia.org/wiki/Socketcan’), on Linux
     (‘https://lwn.net/Articles/253425’).

     (Contributed by Matthias Fuchs, updated by Tiago Gonçalves in
     bpo-10141(2).)

   * The *note socket: dcf. class now supports the PF_RDS protocol
     family (‘https://en.wikipedia.org/wiki/Reliable_Datagram_Sockets’
     and https://oss.oracle.com/projects/rds(3)).

   * The *note socket: dcf. class now supports the ‘PF_SYSTEM’ protocol
     family on OS X. (Contributed by Michael Goderbauer in
     bpo-13777(4).)

   * New function *note sethostname(): 117f. allows the hostname to be
     set on Unix systems if the calling process has sufficient
     privileges.  (Contributed by Ross Lagerwall in bpo-10866(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6560

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10141

   (3) 
https://web.archive.org/web/20130115155505/https://oss.oracle.com/projects/rds/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13777

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10866


File: python.info,  Node: socketserver<3>,  Next: sqlite3<10>,  Prev: socket<10>,  Up: Improved Modules<11>

1.11.20.47 socketserver
.......................

*note BaseServer: 1181. now has an overridable method *note
service_actions(): 1182. that is called by the *note serve_forever():
1183. method in the service loop.  *note ForkingMixIn: b96. now uses
this to clean up zombie child processes.  (Contributed by Justin
Warkentin in bpo-11109(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11109


File: python.info,  Node: sqlite3<10>,  Next: ssl<11>,  Prev: socketserver<3>,  Up: Improved Modules<11>

1.11.20.48 sqlite3
..................

New *note sqlite3.Connection: 245. method *note set_trace_callback():
2ad. can be used to capture a trace of all sql commands processed by
sqlite.  (Contributed by Torsten Landschoff in bpo-11688(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11688


File: python.info,  Node: ssl<11>,  Next: stat<2>,  Prev: sqlite3<10>,  Up: Improved Modules<11>

1.11.20.49 ssl
..............

   * The *note ssl: d0. module has two new random generation functions:

        * *note RAND_bytes(): 527.: generate cryptographically strong
          pseudo-random bytes.

        * ‘RAND_pseudo_bytes()’: generate pseudo-random bytes.

     (Contributed by Victor Stinner in bpo-12049(1).)

   * The *note ssl: d0. module now exposes a finer-grained exception
     hierarchy in order to make it easier to inspect the various kinds
     of errors.  (Contributed by Antoine Pitrou in bpo-11183(2).)

   * *note load_cert_chain(): 295. now accepts a 'password' argument to
     be used if the private key is encrypted.  (Contributed by Adam
     Simpkins in bpo-12803(3).)

   * Diffie-Hellman key exchange, both regular and Elliptic Curve-based,
     is now supported through the *note load_dh_params(): 1186. and
     *note set_ecdh_curve(): 1187. methods.  (Contributed by Antoine
     Pitrou in bpo-13626(4) and bpo-13627(5).)

   * SSL sockets have a new *note get_channel_binding(): 1188. method
     allowing the implementation of certain authentication mechanisms
     such as SCRAM-SHA-1-PLUS. (Contributed by Jacek Konieczny in
     bpo-12551(6).)

   * You can query the SSL compression algorithm used by an SSL socket,
     thanks to its new *note compression(): 1189. method.  The new
     attribute *note OP_NO_COMPRESSION: 118a. can be used to disable
     compression.  (Contributed by Antoine Pitrou in bpo-13634(7).)

   * Support has been added for the Next Protocol Negotiation extension
     using the *note ssl.SSLContext.set_npn_protocols(): 302. method.
     (Contributed by Colin Marc in bpo-14204(8).)

   * SSL errors can now be introspected more easily thanks to *note
     library: 118b. and *note reason: 118c. attributes.  (Contributed by
     Antoine Pitrou in bpo-14837(9).)

   * The *note get_server_certificate(): 842. function now supports
     IPv6.  (Contributed by Charles-François Natali in bpo-11811(10).)

   * New attribute *note OP_CIPHER_SERVER_PREFERENCE: 118d. allows
     setting SSLv3 server sockets to use the server’s cipher ordering
     preference rather than the client’s (bpo-13635(11)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12049

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11183

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12803

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13626

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13627

   (6) https://bugs.python.org/issue?@action=redirect&bpo=12551

   (7) https://bugs.python.org/issue?@action=redirect&bpo=13634

   (8) https://bugs.python.org/issue?@action=redirect&bpo=14204

   (9) https://bugs.python.org/issue?@action=redirect&bpo=14837

   (10) https://bugs.python.org/issue?@action=redirect&bpo=11811

   (11) https://bugs.python.org/issue?@action=redirect&bpo=13635


File: python.info,  Node: stat<2>,  Next: struct<3>,  Prev: ssl<11>,  Up: Improved Modules<11>

1.11.20.50 stat
...............

The undocumented tarfile.filemode function has been moved to *note
stat.filemode(): 118f.  It can be used to convert a file’s mode to a
string of the form ‘-rwxrwxrwx’.

(Contributed by Giampaolo Rodolà in bpo-14807(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14807


File: python.info,  Node: struct<3>,  Next: subprocess<6>,  Prev: stat<2>,  Up: Improved Modules<11>

1.11.20.51 struct
.................

The *note struct: d5. module now supports ‘ssize_t’ and ‘size_t’ via the
new codes ‘n’ and ‘N’, respectively.  (Contributed by Antoine Pitrou in
bpo-3163(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3163


File: python.info,  Node: subprocess<6>,  Next: sys<13>,  Prev: struct<3>,  Up: Improved Modules<11>

1.11.20.52 subprocess
.....................

Command strings can now be bytes objects on posix platforms.
(Contributed by Victor Stinner in bpo-8513(1).)

A new constant *note DEVNULL: 1192. allows suppressing output in a
platform-independent fashion.  (Contributed by Ross Lagerwall in
bpo-5870(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8513

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5870


File: python.info,  Node: sys<13>,  Next: tarfile<9>,  Prev: subprocess<6>,  Up: Improved Modules<11>

1.11.20.53 sys
..............

The *note sys: d9. module has a new *note thread_info: 1194. *note named
tuple: 651. holding information about the thread implementation
(bpo-11223(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=11223


File: python.info,  Node: tarfile<9>,  Next: tempfile<4>,  Prev: sys<13>,  Up: Improved Modules<11>

1.11.20.54 tarfile
..................

*note tarfile: de. now supports ‘lzma’ encoding via the *note lzma: 8a.
module.  (Contributed by Lars Gustäbel in bpo-5689(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5689


File: python.info,  Node: tempfile<4>,  Next: textwrap<2>,  Prev: tarfile<9>,  Up: Improved Modules<11>

1.11.20.55 tempfile
...................

*note tempfile.SpooledTemporaryFile: 696.'s ‘truncate()’ method now
accepts a ‘size’ parameter.  (Contributed by Ryan Kelly in bpo-9957(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9957


File: python.info,  Node: textwrap<2>,  Next: threading<8>,  Prev: tempfile<4>,  Up: Improved Modules<11>

1.11.20.56 textwrap
...................

The *note textwrap: ec. module has a new *note indent(): 276. that makes
it straightforward to add a common prefix to selected lines in a block
of text (bpo-13857(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13857


File: python.info,  Node: threading<8>,  Next: time<8>,  Prev: textwrap<2>,  Up: Improved Modules<11>

1.11.20.57 threading
....................

*note threading.Condition: 1199, *note threading.Semaphore: 119a, *note
threading.BoundedSemaphore: 119b, *note threading.Event: 119c, and *note
threading.Timer: 119d, all of which used to be factory functions
returning a class instance, are now classes and may be subclassed.
(Contributed by Éric Araujo in bpo-10968(1).)

The *note threading.Thread: 956. constructor now accepts a ‘daemon’
keyword argument to override the default behavior of inheriting the
‘daemon’ flag value from the parent thread (bpo-6064(2)).

The formerly private function ‘_thread.get_ident’ is now available as
the public function *note threading.get_ident(): 119e.  This eliminates
several cases of direct access to the ‘_thread’ module in the stdlib.
Third party code that used ‘_thread.get_ident’ should likewise be
changed to use the new public interface.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10968

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6064


File: python.info,  Node: time<8>,  Next: types<7>,  Prev: threading<8>,  Up: Improved Modules<11>

1.11.20.58 time
...............

The PEP 418(1) added new functions to the *note time: ee. module:

   * *note get_clock_info(): 11a0.: Get information on a clock.

   * *note monotonic(): 253.: Monotonic clock (cannot go backward), not
     affected by system clock updates.

   * *note perf_counter(): a97.: Performance counter with the highest
     available resolution to measure a short duration.

   * *note process_time(): a98.: Sum of the system and user CPU time of
     the current process.

Other new functions:

   * *note clock_getres(): 11a1, *note clock_gettime(): 11a2. and *note
     clock_settime(): 11a3. functions with ‘CLOCK_XXX’ constants.
     (Contributed by Victor Stinner in bpo-10278(2).)

To improve cross platform consistency, *note sleep(): 6a0. now raises a
*note ValueError: 202. when passed a negative sleep value.  Previously
this was an error on posix, but produced an infinite sleep on Windows.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0418/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10278


File: python.info,  Node: types<7>,  Next: unittest<10>,  Prev: time<8>,  Up: Improved Modules<11>

1.11.20.59 types
................

Add a new *note types.MappingProxyType: 470. class: Read-only proxy of a
mapping.  (bpo-14386(1))

The new functions *note types.new_class(): 11a5. and *note
types.prepare_class(): 11a6. provide support for PEP 3115(2) compliant
dynamic type creation.  (bpo-14588(3))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14386

   (2) https://peps.python.org/pep-3115/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=14588


File: python.info,  Node: unittest<10>,  Next: urllib<4>,  Prev: types<7>,  Up: Improved Modules<11>

1.11.20.60 unittest
...................

*note assertRaises(): 530, *note assertRaisesRegex(): 532, *note
assertWarns(): 11a8, and *note assertWarnsRegex(): 11a9. now accept a
keyword argument 'msg' when used as context managers.  (Contributed by
Ezio Melotti and Winston Ewert in bpo-10775(1).)

*note unittest.TestCase.run(): 11aa. now returns the *note TestResult:
11ab. object.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10775


File: python.info,  Node: urllib<4>,  Next: webbrowser<3>,  Prev: unittest<10>,  Up: Improved Modules<11>

1.11.20.61 urllib
.................

The *note Request: 1013. class, now accepts a 'method' argument used by
*note get_method(): 11ad. to determine what HTTP method should be used.
For example, this will send a ‘'HEAD'’ request:

     >>> urlopen(Request('https://www.python.org', method='HEAD'))

(bpo-1673007(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1673007


File: python.info,  Node: webbrowser<3>,  Next: xml etree ElementTree<2>,  Prev: urllib<4>,  Up: Improved Modules<11>

1.11.20.62 webbrowser
.....................

The *note webbrowser: 115. module supports more “browsers”: Google
Chrome (named ‘chrome’, ‘chromium’, ‘chrome-browser’ or
‘chromium-browser’ depending on the version and operating system), and
the generic launchers ‘xdg-open’, from the FreeDesktop.org project, and
‘gvfs-open’, which is the default URI handler for GNOME 3.  (The former
contributed by Arnaud Calmettes in bpo-13620(1), the latter by Matthias
Klose in bpo-14493(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13620

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14493


File: python.info,  Node: xml etree ElementTree<2>,  Next: zlib<2>,  Prev: webbrowser<3>,  Up: Improved Modules<11>

1.11.20.63 xml.etree.ElementTree
................................

The *note xml.etree.ElementTree: 125. module now imports its C
accelerator by default; there is no longer a need to explicitly import
‘xml.etree.cElementTree’ (this module stays for backwards compatibility,
but is now deprecated).  In addition, the ‘iter’ family of methods of
*note Element: 310. has been optimized (rewritten in C). The module’s
documentation has also been greatly improved with added examples and a
more detailed reference.


File: python.info,  Node: zlib<2>,  Prev: xml etree ElementTree<2>,  Up: Improved Modules<11>

1.11.20.64 zlib
...............

New attribute *note zlib.Decompress.eof: 11b1. makes it possible to
distinguish between a properly formed compressed stream and an
incomplete or truncated one.  (Contributed by Nadeem Vawda in
bpo-12646(1).)

New attribute *note zlib.ZLIB_RUNTIME_VERSION: 11b2. reports the version
string of the underlying ‘zlib’ library that is loaded at runtime.
(Contributed by Torsten Landschoff in bpo-12306(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12646

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12306


File: python.info,  Node: Optimizations<10>,  Next: Build and C API Changes<4>,  Prev: Improved Modules<11>,  Up: What’s New In Python 3 3

1.11.21 Optimizations
---------------------

Major performance enhancements have been added:

   * Thanks to PEP 393(1), some operations on Unicode strings have been
     optimized:

        * the memory footprint is divided by 2 to 4 depending on the
          text

        * encode an ASCII string to UTF-8 doesn’t need to encode
          characters anymore, the UTF-8 representation is shared with
          the ASCII representation

        * the UTF-8 encoder has been optimized

        * repeating a single ASCII letter and getting a substring of an
          ASCII string is 4 times faster

   * UTF-8 is now 2x to 4x faster.  UTF-16 encoding is now up to 10x
     faster.

     (Contributed by Serhiy Storchaka, bpo-14624(2), bpo-14738(3) and
     bpo-15026(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=14624

   (3) https://bugs.python.org/issue?@action=redirect&bpo=14738

   (4) https://bugs.python.org/issue?@action=redirect&bpo=15026


File: python.info,  Node: Build and C API Changes<4>,  Next: Deprecated<12>,  Prev: Optimizations<10>,  Up: What’s New In Python 3 3

1.11.22 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * New PEP 3118(1) related function:

        * *note PyMemoryView_FromMemory(): 11b4.

   * PEP 393(2) added new Unicode types, macros and functions:

        * High-level API:

             * *note PyUnicode_CopyCharacters(): 8bd.

             * *note PyUnicode_FindChar(): 8c1.

             * *note PyUnicode_GetLength(): 8bb, *note
               PyUnicode_GET_LENGTH: 8bc.

             * *note PyUnicode_New(): 8b3.

             * *note PyUnicode_Substring(): 8be.

             * *note PyUnicode_ReadChar(): 11b5, *note
               PyUnicode_WriteChar(): 11b6.

        * Low-level API:

             * *note Py_UCS1: 11b7, *note Py_UCS2: 11b8, *note Py_UCS4:
               29b. types

             * *note PyASCIIObject: 11b9. and *note
               PyCompactUnicodeObject: 11ba. structures

             * *note PyUnicode_READY: 404.

             * *note PyUnicode_FromKindAndData(): 11bb.

             * *note PyUnicode_AsUCS4(): 11bc, *note
               PyUnicode_AsUCS4Copy(): 8c3.

             * *note PyUnicode_DATA: 11bd, *note PyUnicode_1BYTE_DATA:
               11be, *note PyUnicode_2BYTE_DATA: 11bf, *note
               PyUnicode_4BYTE_DATA: 11c0.

             * *note PyUnicode_KIND: 11c1. with ‘PyUnicode_Kind’ enum:
               ‘PyUnicode_WCHAR_KIND’, *note PyUnicode_1BYTE_KIND: 11c2,
               *note PyUnicode_2BYTE_KIND: 11c3, *note
               PyUnicode_4BYTE_KIND: 11c4.

             * *note PyUnicode_READ: 11c5, *note PyUnicode_READ_CHAR:
               11c6, *note PyUnicode_WRITE: 11c7.

             * *note PyUnicode_MAX_CHAR_VALUE: 11c8.

   * *note PyArg_ParseTuple: 574. now accepts a *note bytearray: 2ea.
     for the ‘c’ format (bpo-12380(3)).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/

   (2) https://peps.python.org/pep-0393/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12380


File: python.info,  Node: Deprecated<12>,  Next: Porting to Python 3 3,  Prev: Build and C API Changes<4>,  Up: What’s New In Python 3 3

1.11.23 Deprecated
------------------

* Menu:

* Unsupported Operating Systems: Unsupported Operating Systems<2>.
* Deprecated Python modules, functions and methods: Deprecated Python modules functions and methods<4>.
* Deprecated functions and types of the C API: Deprecated functions and types of the C API<3>.
* Deprecated features::


File: python.info,  Node: Unsupported Operating Systems<2>,  Next: Deprecated Python modules functions and methods<4>,  Up: Deprecated<12>

1.11.23.1 Unsupported Operating Systems
.......................................

OS/2 and VMS are no longer supported due to the lack of a maintainer.

Windows 2000 and Windows platforms which set ‘COMSPEC’ to ‘command.com’
are no longer supported due to maintenance burden.

OSF support, which was deprecated in 3.2, has been completely removed.


File: python.info,  Node: Deprecated Python modules functions and methods<4>,  Next: Deprecated functions and types of the C API<3>,  Prev: Unsupported Operating Systems<2>,  Up: Deprecated<12>

1.11.23.2 Deprecated Python modules, functions and methods
..........................................................

   * Passing a non-empty string to ‘object.__format__()’ is deprecated,
     and will produce a *note TypeError: 2c3. in Python 3.4
     (bpo-9856(1)).

   * The ‘unicode_internal’ codec has been deprecated because of the PEP
     393(2), use UTF-8, UTF-16 (‘utf-16-le’ or ‘utf-16-be’), or UTF-32
     (‘utf-32-le’ or ‘utf-32-be’)

   * *note ftplib.FTP.nlst(): 1107. and *note ftplib.FTP.dir(): 1108.:
     use *note ftplib.FTP.mlsd(): 1106.

   * ‘platform.popen()’: use the *note subprocess: d6. module.  Check
     especially the *note Replacing Older Functions with the subprocess
     Module: 11cc. section (bpo-11377(3)).

   * bpo-13374(4): The Windows bytes API has been deprecated in the
     *note os: a1. module.  Use Unicode filenames, instead of bytes
     filenames, to not depend on the ANSI code page anymore and to
     support any filename.

   * bpo-13988(5): The ‘xml.etree.cElementTree’ module is deprecated.
     The accelerator is used automatically whenever available.

   * The behaviour of ‘time.clock()’ depends on the platform: use the
     new *note time.perf_counter(): a97. or *note time.process_time():
     a98. function instead, depending on your requirements, to have a
     well defined behaviour.

   * The ‘os.stat_float_times()’ function is deprecated.

   * *note abc: 4. module:

        * *note abc.abstractproperty: 10c8. has been deprecated, use
          *note property: 194. with *note abc.abstractmethod(): 10c9.
          instead.

        * *note abc.abstractclassmethod: 10ca. has been deprecated, use
          *note classmethod: 166. with *note abc.abstractmethod(): 10c9.
          instead.

        * *note abc.abstractstaticmethod: 10cb. has been deprecated, use
          *note staticmethod: 419. with *note abc.abstractmethod():
          10c9. instead.

   * *note importlib: 77. package:

        * *note importlib.abc.SourceLoader.path_mtime(): 11cd. is now
          deprecated in favour of *note
          importlib.abc.SourceLoader.path_stats(): 11ce. as bytecode
          files now store both the modification time and size of the
          source file the bytecode file was compiled from.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9856

   (2) https://peps.python.org/pep-0393/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=11377

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13374

   (5) https://bugs.python.org/issue?@action=redirect&bpo=13988


File: python.info,  Node: Deprecated functions and types of the C API<3>,  Next: Deprecated features,  Prev: Deprecated Python modules functions and methods<4>,  Up: Deprecated<12>

1.11.23.3 Deprecated functions and types of the C API
.....................................................

The *note Py_UNICODE: 3f0. has been deprecated by PEP 393(1) and will be
removed in Python 4.  All functions using this type are deprecated:

Unicode functions and methods using *note Py_UNICODE: 3f0. and *note
Py_UNICODE: 3f0.* types:

   * ‘PyUnicode_FromUnicode’: use *note PyUnicode_FromWideChar(): 11d0.
     or *note PyUnicode_FromKindAndData(): 11bb.

   * ‘PyUnicode_AS_UNICODE’, ‘PyUnicode_AsUnicode()’,
     ‘PyUnicode_AsUnicodeAndSize()’: use *note
     PyUnicode_AsWideCharString(): 8c4.

   * ‘PyUnicode_AS_DATA’: use *note PyUnicode_DATA: 11bd. with *note
     PyUnicode_READ: 11c5. and *note PyUnicode_WRITE: 11c7.

   * ‘PyUnicode_GET_SIZE’, ‘PyUnicode_GetSize()’: use *note
     PyUnicode_GET_LENGTH: 8bc. or *note PyUnicode_GetLength(): 8bb.

   * ‘PyUnicode_GET_DATA_SIZE’: use ‘PyUnicode_GET_LENGTH(str) *
     PyUnicode_KIND(str)’ (only work on ready strings)

   * ‘PyUnicode_AsUnicodeCopy()’: use *note PyUnicode_AsUCS4Copy(): 8c3.
     or *note PyUnicode_AsWideCharString(): 8c4.

   * ‘PyUnicode_GetMax()’

Functions and macros manipulating Py_UNICODE* strings:

   * ‘Py_UNICODE_strlen()’: use *note PyUnicode_GetLength(): 8bb. or
     *note PyUnicode_GET_LENGTH: 8bc.

   * ‘Py_UNICODE_strcat()’: use *note PyUnicode_CopyCharacters(): 8bd.
     or *note PyUnicode_FromFormat(): 38d.

   * ‘Py_UNICODE_strcpy()’, ‘Py_UNICODE_strncpy()’, ‘Py_UNICODE_COPY()’:
     use *note PyUnicode_CopyCharacters(): 8bd. or *note
     PyUnicode_Substring(): 8be.

   * ‘Py_UNICODE_strcmp()’: use *note PyUnicode_Compare(): 8bf.

   * ‘Py_UNICODE_strncmp()’: use *note PyUnicode_Tailmatch(): 8c0.

   * ‘Py_UNICODE_strchr()’, ‘Py_UNICODE_strrchr()’: use *note
     PyUnicode_FindChar(): 8c1.

   * ‘Py_UNICODE_FILL()’: use *note PyUnicode_Fill(): 11d1.

   * ‘Py_UNICODE_MATCH’

Encoders:

   * ‘PyUnicode_Encode()’: use ‘PyUnicode_AsEncodedObject()’

   * ‘PyUnicode_EncodeUTF7()’

   * ‘PyUnicode_EncodeUTF8()’: use *note PyUnicode_AsUTF8(): bda. or
     *note PyUnicode_AsUTF8String(): 11d2.

   * ‘PyUnicode_EncodeUTF32()’

   * ‘PyUnicode_EncodeUTF16()’

   * ‘PyUnicode_EncodeUnicodeEscape()’ use *note
     PyUnicode_AsUnicodeEscapeString(): 11d3.

   * ‘PyUnicode_EncodeRawUnicodeEscape()’ use *note
     PyUnicode_AsRawUnicodeEscapeString(): 11d4.

   * ‘PyUnicode_EncodeLatin1()’: use *note PyUnicode_AsLatin1String():
     11d5.

   * ‘PyUnicode_EncodeASCII()’: use *note PyUnicode_AsASCIIString():
     11d6.

   * ‘PyUnicode_EncodeCharmap()’

   * ‘PyUnicode_TranslateCharmap()’

   * ‘PyUnicode_EncodeMBCS()’: use *note PyUnicode_AsMBCSString(): 11d7.
     or *note PyUnicode_EncodeCodePage(): 11d8. (with ‘CP_ACP’
     code_page)

   * ‘PyUnicode_EncodeDecimal()’, ‘PyUnicode_TransformDecimalToASCII()’

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/


File: python.info,  Node: Deprecated features,  Prev: Deprecated functions and types of the C API<3>,  Up: Deprecated<12>

1.11.23.4 Deprecated features
.............................

The *note array: 7. module’s ‘'u'’ format code is now deprecated and
will be removed in Python 4 together with the rest of the (*note
Py_UNICODE: 3f0.) API.


File: python.info,  Node: Porting to Python 3 3,  Prev: Deprecated<12>,  Up: What’s New In Python 3 3

1.11.24 Porting to Python 3.3
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code.

* Menu:

* Porting Python code::
* Porting C code::
* Building C extensions::
* Command Line Switch Changes::


File: python.info,  Node: Porting Python code,  Next: Porting C code,  Up: Porting to Python 3 3

1.11.24.1 Porting Python code
.............................

   * Hash randomization is enabled by default.  Set the *note
     PYTHONHASHSEED: 10bb. environment variable to ‘0’ to disable hash
     randomization.  See also the *note object.__hash__(): b14. method.

   * bpo-12326(1): On Linux, sys.platform doesn’t contain the major
     version anymore.  It is now always ‘linux’, instead of ‘linux2’ or
     ‘linux3’ depending on the Linux version used to build Python.
     Replace sys.platform == ‘linux2’ with
     sys.platform.startswith(‘linux’), or directly sys.platform ==
     ‘linux’ if you don’t need to support older Python versions.

   * bpo-13847(2), bpo-14180(3): *note time: ee. and *note datetime:
     30.: *note OverflowError: 888. is now raised instead of *note
     ValueError: 202. if a timestamp is out of range.  *note OSError:
     41a. is now raised if C functions ‘gmtime()’ or ‘localtime()’
     failed.

   * The default finders used by import now utilize a cache of what is
     contained within a specific directory.  If you create a Python
     source file or sourceless bytecode file, make sure to call *note
     importlib.invalidate_caches(): c30. to clear out the cache for the
     finders to notice the new file.

   * *note ImportError: 41c. now uses the full name of the module that
     was attempted to be imported.  Doctests that check ImportErrors’
     message will need to be updated to use the full name of the module
     instead of just the tail of the name.

   * The 'index' argument to *note __import__(): 8dd. now defaults to 0
     instead of -1 and no longer support negative values.  It was an
     oversight when PEP 328(4) was implemented that the default value
     remained -1.  If you need to continue to perform a relative import
     followed by an absolute import, then perform the relative import
     using an index of 1, followed by another import using an index of
     0.  It is preferred, though, that you use *note
     importlib.import_module(): 51b. rather than call ‘__import__()’
     directly.

   * *note __import__(): 8dd. no longer allows one to use an index value
     other than 0 for top-level modules.  E.g.  ‘__import__('sys',
     level=1)’ is now an error.

   * Because *note sys.meta_path: d53. and *note sys.path_hooks: 105f.
     now have finders on them by default, you will most likely want to
     use *note list.insert(): 11dc. instead of *note list.append(): 6d0.
     to add to those lists.

   * Because ‘None’ is now inserted into *note sys.path_importer_cache:
     5e7, if you are clearing out entries in the dictionary of paths
     that do not have a finder, you will need to remove keys paired with
     values of ‘None’ 'and' ‘imp.NullImporter’ to be
     backwards-compatible.  This will lead to extra overhead on older
     versions of Python that re-insert ‘None’ into
     ‘sys.path_importer_cache’ where it represents the use of implicit
     finders, but semantically it should not change anything.

   * ‘importlib.abc.Finder’ no longer specifies a ‘find_module()’
     abstract method that must be implemented.  If you were relying on
     subclasses to implement that method, make sure to check for the
     method’s existence first.  You will probably want to check for
     ‘find_loader()’ first, though, in the case of working with *note
     path entry finders: 10af.

   * *note pkgutil: a9. has been converted to use *note importlib: 77.
     internally.  This eliminates many edge cases where the old
     behaviour of the PEP 302(5) import emulation failed to match the
     behaviour of the real import system.  The import emulation itself
     is still present, but is now deprecated.  The *note
     pkgutil.iter_importers(): 11dd. and *note pkgutil.walk_packages():
     c1f. functions special case the standard import hooks so they are
     still supported even though they do not provide the non-standard
     ‘iter_modules()’ method.

   * A longstanding RFC-compliance bug (bpo-1079(6)) in the parsing done
     by *note email.header.decode_header(): 10fc. has been fixed.  Code
     that uses the standard idiom to convert encoded headers into
     unicode (‘str(make_header(decode_header(h))’) will see no change,
     but code that looks at the individual tuples returned by
     decode_header will see that whitespace that precedes or follows
     ‘ASCII’ sections is now included in the ‘ASCII’ section.  Code that
     builds headers using ‘make_header’ should also continue to work
     without change, since ‘make_header’ continues to add whitespace
     between ‘ASCII’ and non-‘ASCII’ sections if it is not already
     present in the input strings.

   * *note email.utils.formataddr(): 11de. now does the correct content
     transfer encoding when passed non-‘ASCII’ display names.  Any code
     that depended on the previous buggy behavior that preserved the
     non-‘ASCII’ unicode in the formatted output string will need to be
     changed (bpo-1690608(7)).

   * *note poplib.POP3.quit(): 11df. may now raise protocol errors like
     all other ‘poplib’ methods.  Code that assumes ‘quit’ does not
     raise *note poplib.error_proto: 11e0. errors may need to be changed
     if errors on ‘quit’ are encountered by a particular application
     (bpo-11291(8)).

   * The ‘strict’ argument to *note email.parser.Parser: 11e1,
     deprecated since Python 2.4, has finally been removed.

   * The deprecated method ‘unittest.TestCase.assertSameElements’ has
     been removed.

   * The deprecated variable ‘time.accept2dyear’ has been removed.

   * The deprecated ‘Context._clamp’ attribute has been removed from the
     *note decimal: 36. module.  It was previously replaced by the
     public attribute *note clamp: 11e2.  (See bpo-8540(9).)

   * The undocumented internal helper class ‘SSLFakeFile’ has been
     removed from *note smtplib: ca, since its functionality has long
     been provided directly by *note socket.socket.makefile(): 11e3.

   * Passing a negative value to *note time.sleep(): 6a0. on Windows now
     raises an error instead of sleeping forever.  It has always raised
     an error on posix.

   * The ‘ast.__version__’ constant has been removed.  If you need to
     make decisions affected by the AST version, use *note
     sys.version_info: 6a3. to make the decision.

   * Code that used to work around the fact that the *note threading:
     ed. module used factory functions by subclassing the private
     classes will need to change to subclass the now-public classes.

   * The undocumented debugging machinery in the threading module has
     been removed, simplifying the code.  This should have no effect on
     production code, but is mentioned here in case any application
     debug frameworks were interacting with it (bpo-13550(10)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=12326

   (2) https://bugs.python.org/issue?@action=redirect&bpo=13847

   (3) https://bugs.python.org/issue?@action=redirect&bpo=14180

   (4) https://peps.python.org/pep-0328/

   (5) https://peps.python.org/pep-0302/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1079

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1690608

   (8) https://bugs.python.org/issue?@action=redirect&bpo=11291

   (9) https://bugs.python.org/issue?@action=redirect&bpo=8540

   (10) https://bugs.python.org/issue?@action=redirect&bpo=13550


File: python.info,  Node: Porting C code,  Next: Building C extensions,  Prev: Porting Python code,  Up: Porting to Python 3 3

1.11.24.2 Porting C code
........................

   * In the course of changes to the buffer API the undocumented
     ‘smalltable’ member of the *note Py_buffer: 75b. structure has been
     removed and the layout of the ‘PyMemoryViewObject’ has changed.

     All extensions relying on the relevant parts in ‘memoryobject.h’ or
     ‘object.h’ must be rebuilt.

   * Due to *note PEP 393: 107b, the *note Py_UNICODE: 3f0. type and all
     functions using this type are deprecated (but will stay available
     for at least five years).  If you were using low-level Unicode APIs
     to construct and access unicode objects and you want to benefit of
     the memory footprint reduction provided by PEP 393(1), you have to
     convert your code to the new *note Unicode API: 11e4.

     However, if you only have been using high-level functions such as
     *note PyUnicode_Concat(): 11e5, *note PyUnicode_Join(): 11e6. or
     *note PyUnicode_FromFormat(): 38d, your code will automatically
     take advantage of the new unicode representations.

   * *note PyImport_GetMagicNumber(): 11e7. now returns ‘-1’ upon
     failure.

   * As a negative value for the 'level' argument to *note __import__():
     8dd. is no longer valid, the same now holds for *note
     PyImport_ImportModuleLevel(): 11e8.  This also means that the value
     of 'level' used by *note PyImport_ImportModuleEx(): 11e9. is now
     ‘0’ instead of ‘-1’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/


File: python.info,  Node: Building C extensions,  Next: Command Line Switch Changes,  Prev: Porting C code,  Up: Porting to Python 3 3

1.11.24.3 Building C extensions
...............................

   * The range of possible file names for C extensions has been
     narrowed.  Very rarely used spellings have been suppressed: under
     POSIX, files named ‘xxxmodule.so’, ‘xxxmodule.abi3.so’ and
     ‘xxxmodule.cpython-*.so’ are no longer recognized as implementing
     the ‘xxx’ module.  If you had been generating such files, you have
     to switch to the other spellings (i.e., remove the ‘module’ string
     from the file names).

     (implemented in bpo-14040(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14040


File: python.info,  Node: Command Line Switch Changes,  Prev: Building C extensions,  Up: Porting to Python 3 3

1.11.24.4 Command Line Switch Changes
.....................................

   * The -Q command-line flag and related artifacts have been removed.
     Code checking sys.flags.division_warning will need updating.

     (bpo-10998(1), contributed by Éric Araujo.)

   * When ‘python’ is started with *note -S: 11ec, ‘import site’ will no
     longer add site-specific paths to the module search paths.  In
     previous versions, it did.

     (bpo-11591(2), contributed by Carl Meyer with editions by Éric
     Araujo.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10998

   (2) https://bugs.python.org/issue?@action=redirect&bpo=11591


File: python.info,  Node: What’s New In Python 3 2,  Next: What’s New In Python 3 1,  Prev: What’s New In Python 3 3,  Up: What’s New in Python

1.12 What’s New In Python 3.2
=============================


Author: Raymond Hettinger

This article explains the new features in Python 3.2 as compared to 3.1.
Python 3.2 was released on February 20, 2011.  It focuses on a few
highlights and gives a few examples.  For full details, see the
Misc/NEWS(1) file.

See also
........

PEP 392(2) - Python 3.2 Release Schedule

* Menu:

* PEP 384; Defining a Stable ABI: PEP 384 Defining a Stable ABI.
* PEP 389; Argparse Command Line Parsing Module: PEP 389 Argparse Command Line Parsing Module.
* PEP 391; Dictionary Based Configuration for Logging: PEP 391 Dictionary Based Configuration for Logging.
* PEP 3148; The concurrent.futures module: PEP 3148 The concurrent futures module.
* PEP 3147; PYC Repository Directories: PEP 3147 PYC Repository Directories.
* PEP 3149; ABI Version Tagged .so Files: PEP 3149 ABI Version Tagged so Files.
* PEP 3333; Python Web Server Gateway Interface v1.0.1: PEP 3333 Python Web Server Gateway Interface v1 0 1.
* Other Language Changes: Other Language Changes<12>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules.
* Multi-threading::
* Optimizations: Optimizations<11>.
* Unicode::
* Codecs::
* Documentation::
* IDLE::
* Code Repository::
* Build and C API Changes: Build and C API Changes<5>.
* Porting to Python 3.2: Porting to Python 3 2.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/blob/076ca6c3c8df3030307e548d9be792ce3c1c6eea/Misc/NEWS

   (2) https://peps.python.org/pep-0392/


File: python.info,  Node: PEP 384 Defining a Stable ABI,  Next: PEP 389 Argparse Command Line Parsing Module,  Up: What’s New In Python 3 2

1.12.1 PEP 384: Defining a Stable ABI
-------------------------------------

In the past, extension modules built for one Python version were often
not usable with other Python versions.  Particularly on Windows, every
feature release of Python required rebuilding all extension modules that
one wanted to use.  This requirement was the result of the free access
to Python interpreter internals that extension modules could use.

With Python 3.2, an alternative approach becomes available: extension
modules which restrict themselves to a limited API (by defining
Py_LIMITED_API) cannot use many of the internals, but are constrained to
a set of API functions that are promised to be stable for several
releases.  As a consequence, extension modules built for 3.2 in that
mode will also work with 3.3, 3.4, and so on.  Extension modules that
make use of details of memory structures can still be built, but will
need to be recompiled for every feature release.

See also
........

PEP 384(1) - Defining a Stable ABI

     PEP written by Martin von Löwis.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0384/


File: python.info,  Node: PEP 389 Argparse Command Line Parsing Module,  Next: PEP 391 Dictionary Based Configuration for Logging,  Prev: PEP 384 Defining a Stable ABI,  Up: What’s New In Python 3 2

1.12.2 PEP 389: Argparse Command Line Parsing Module
----------------------------------------------------

A new module for command line parsing, *note argparse: 6, was introduced
to overcome the limitations of *note optparse: a0. which did not provide
support for positional arguments (not just options), subcommands,
required options and other common patterns of specifying and validating
options.

This module has already had widespread success in the community as a
third-party module.  Being more fully featured than its predecessor, the
*note argparse: 6. module is now the preferred module for command-line
processing.  The older module is still being kept available because of
the substantial amount of legacy code that depends on it.

Here’s an annotated example parser showing features like limiting
results to a set of choices, specifying a 'metavar' in the help screen,
validating that one or more positional arguments is present, and making
a required option:

     import argparse
     parser = argparse.ArgumentParser(
                 description = 'Manage servers',         # main description for help
                 epilog = 'Tested on Solaris and Linux') # displayed after help
     parser.add_argument('action',                       # argument name
                 choices = ['deploy', 'start', 'stop'],  # three allowed values
                 help = 'action on each target')         # help msg
     parser.add_argument('targets',
                 metavar = 'HOSTNAME',                   # var name used in help msg
                 nargs = '+',                            # require one or more targets
                 help = 'url for target machines')       # help msg explanation
     parser.add_argument('-u', '--user',                 # -u or --user option
                 required = True,                        # make it a required argument
                 help = 'login as user')

Example of calling the parser on a command string:

     >>> cmd = 'deploy sneezy.example.com sleepy.example.com -u skycaptain'
     >>> result = parser.parse_args(cmd.split())
     >>> result.action
     'deploy'
     >>> result.targets
     ['sneezy.example.com', 'sleepy.example.com']
     >>> result.user
     'skycaptain'

Example of the parser’s automatically generated help:

     >>> parser.parse_args('-h'.split())

     usage: manage_cloud.py [-h] -u USER
                            {deploy,start,stop} HOSTNAME [HOSTNAME ...]

     Manage servers

     positional arguments:
       {deploy,start,stop}   action on each target
       HOSTNAME              url for target machines

     optional arguments:
       -h, --help            show this help message and exit
       -u USER, --user USER  login as user

     Tested on Solaris and Linux

An especially nice *note argparse: 6. feature is the ability to define
subparsers, each with their own argument patterns and help displays:

     import argparse
     parser = argparse.ArgumentParser(prog='HELM')
     subparsers = parser.add_subparsers()

     parser_l = subparsers.add_parser('launch', help='Launch Control')   # first subgroup
     parser_l.add_argument('-m', '--missiles', action='store_true')
     parser_l.add_argument('-t', '--torpedos', action='store_true')

     parser_m = subparsers.add_parser('move', help='Move Vessel',        # second subgroup
                                      aliases=('steer', 'turn'))         # equivalent names
     parser_m.add_argument('-c', '--course', type=int, required=True)
     parser_m.add_argument('-s', '--speed', type=int, default=0)

     $ ./helm.py --help                         # top level help (launch and move)
     $ ./helm.py launch --help                  # help for launch options
     $ ./helm.py launch --missiles              # set missiles=True and torpedos=False
     $ ./helm.py steer --course 180 --speed 5   # set movement parameters

See also
........

PEP 389(1) - New Command Line Parsing Module

     PEP written by Steven Bethard.

*note Migrating optparse code to argparse: 11f2. for details on the
differences from *note optparse: a0.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0389/


File: python.info,  Node: PEP 391 Dictionary Based Configuration for Logging,  Next: PEP 3148 The concurrent futures module,  Prev: PEP 389 Argparse Command Line Parsing Module,  Up: What’s New In Python 3 2

1.12.3 PEP 391: Dictionary Based Configuration for Logging
----------------------------------------------------------

The *note logging: 87. module provided two kinds of configuration, one
style with function calls for each option or another style driven by an
external file saved in a *note configparser: 22. format.  Those options
did not provide the flexibility to create configurations from JSON or
YAML files, nor did they support incremental configuration, which is
needed for specifying logger options from a command line.

To support a more flexible style, the module now offers *note
logging.config.dictConfig(): 11f4. for specifying logging configuration
with plain Python dictionaries.  The configuration options include
formatters, handlers, filters, and loggers.  Here’s a working example of
a configuration dictionary:

     {"version": 1,
      "formatters": {"brief": {"format": "%(levelname)-8s: %(name)-15s: %(message)s"},
                     "full": {"format": "%(asctime)s %(name)-15s %(levelname)-8s %(message)s"}
                     },
      "handlers": {"console": {
                        "class": "logging.StreamHandler",
                        "formatter": "brief",
                        "level": "INFO",
                        "stream": "ext://sys.stdout"},
                   "console_priority": {
                        "class": "logging.StreamHandler",
                        "formatter": "full",
                        "level": "ERROR",
                        "stream": "ext://sys.stderr"}
                   },
      "root": {"level": "DEBUG", "handlers": ["console", "console_priority"]}}

If that dictionary is stored in a file called ‘conf.json’, it can be
loaded and called with code like this:

     >>> import json, logging.config
     >>> with open('conf.json') as f:
     ...     conf = json.load(f)
     ...
     >>> logging.config.dictConfig(conf)
     >>> logging.info("Transaction completed normally")
     INFO    : root           : Transaction completed normally
     >>> logging.critical("Abnormal termination")
     2011-02-17 11:14:36,694 root            CRITICAL Abnormal termination

See also
........

PEP 391(1) - Dictionary Based Configuration for Logging

     PEP written by Vinay Sajip.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0391/


File: python.info,  Node: PEP 3148 The concurrent futures module,  Next: PEP 3147 PYC Repository Directories,  Prev: PEP 391 Dictionary Based Configuration for Logging,  Up: What’s New In Python 3 2

1.12.4 PEP 3148: The ‘concurrent.futures’ module
------------------------------------------------

Code for creating and managing concurrency is being collected in a new
top-level namespace, 'concurrent'.  Its first member is a 'futures'
package which provides a uniform high-level interface for managing
threads and processes.

The design for *note concurrent.futures: 21. was inspired by the
'java.util.concurrent' package.  In that model, a running call and its
result are represented by a *note Future: 11f6. object that abstracts
features common to threads, processes, and remote procedure calls.  That
object supports status checks (running or done), timeouts,
cancellations, adding callbacks, and access to results or exceptions.

The primary offering of the new module is a pair of executor classes for
launching and managing calls.  The goal of the executors is to make it
easier to use existing tools for making parallel calls.  They save the
effort needed to setup a pool of resources, launch the calls, create a
results queue, add time-out handling, and limit the total number of
threads, processes, or remote procedure calls.

Ideally, each application should share a single executor across multiple
components so that process and thread limits can be centrally managed.
This solves the design challenge that arises when each component has its
own competing strategy for resource management.

Both classes share a common interface with three methods: *note
submit(): a91. for scheduling a callable and returning a *note Future:
11f6. object; *note map(): e14. for scheduling many asynchronous calls
at a time, and *note shutdown(): 8f6. for freeing resources.  The class
is a *note context manager: 5d7. and can be used in a *note with: 5d5.
statement to assure that resources are automatically released when
currently pending futures are done executing.

A simple of example of *note ThreadPoolExecutor: 745. is a launch of
four parallel threads for copying files:

     import concurrent.futures, shutil
     with concurrent.futures.ThreadPoolExecutor(max_workers=4) as e:
         e.submit(shutil.copy, 'src1.txt', 'dest1.txt')
         e.submit(shutil.copy, 'src2.txt', 'dest2.txt')
         e.submit(shutil.copy, 'src3.txt', 'dest3.txt')
         e.submit(shutil.copy, 'src3.txt', 'dest4.txt')

See also
........

PEP 3148(1) - Futures – Execute Computations Asynchronously

     PEP written by Brian Quinlan.

*note Code for Threaded Parallel URL reads: 11f7, an example using
threads to fetch multiple web pages in parallel.

*note Code for computing prime numbers in parallel: 11f8, an example
demonstrating *note ProcessPoolExecutor: 8f7.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3148/


File: python.info,  Node: PEP 3147 PYC Repository Directories,  Next: PEP 3149 ABI Version Tagged so Files,  Prev: PEP 3148 The concurrent futures module,  Up: What’s New In Python 3 2

1.12.5 PEP 3147: PYC Repository Directories
-------------------------------------------

Python’s scheme for caching bytecode in '.pyc' files did not work well
in environments with multiple Python interpreters.  If one interpreter
encountered a cached file created by another interpreter, it would
recompile the source and overwrite the cached file, thus losing the
benefits of caching.

The issue of “pyc fights” has become more pronounced as it has become
commonplace for Linux distributions to ship with multiple versions of
Python.  These conflicts also arise with CPython alternatives such as
Unladen Swallow.

To solve this problem, Python’s import machinery has been extended to
use distinct filenames for each interpreter.  Instead of Python 3.2 and
Python 3.3 and Unladen Swallow each competing for a file called
“mymodule.pyc”, they will now look for “mymodule.cpython-32.pyc”,
“mymodule.cpython-33.pyc”, and “mymodule.unladen10.pyc”.  And to prevent
all of these new files from cluttering source directories, the 'pyc'
files are now collected in a “__pycache__” directory stored under the
package directory.

Aside from the filenames and target directories, the new scheme has a
few aspects that are visible to the programmer:

   * Imported modules now have a *note __cached__: 2d5. attribute which
     stores the name of the actual file that was imported:

          >>> import collections
          >>> collections.__cached__
          'c:/py32/lib/__pycache__/collections.cpython-32.pyc'

   * The tag that is unique to each interpreter is accessible from the
     ‘imp’ module:

          >>> import imp
          >>> imp.get_tag()
          'cpython-32'

   * Scripts that try to deduce source filename from the imported file
     now need to be smarter.  It is no longer sufficient to simply strip
     the “c” from a “.pyc” filename.  Instead, use the new functions in
     the ‘imp’ module:

          >>> imp.source_from_cache('c:/py32/lib/__pycache__/collections.cpython-32.pyc')
          'c:/py32/lib/collections.py'
          >>> imp.cache_from_source('c:/py32/lib/collections.py')
          'c:/py32/lib/__pycache__/collections.cpython-32.pyc'

   * The *note py_compile: b3. and *note compileall: 20. modules have
     been updated to reflect the new naming convention and target
     directory.  The command-line invocation of 'compileall' has new
     options: ‘-i’ for specifying a list of files and directories to
     compile and ‘-b’ which causes bytecode files to be written to their
     legacy location rather than '__pycache__'.

   * The *note importlib.abc: 78. module has been updated with new *note
     abstract base classes: 11fa. for loading bytecode files.  The
     obsolete ABCs, ‘PyLoader’ and ‘PyPycLoader’, have been deprecated
     (instructions on how to stay Python 3.1 compatible are included
     with the documentation).

See also
........

PEP 3147(1) - PYC Repository Directories

     PEP written by Barry Warsaw.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: PEP 3149 ABI Version Tagged so Files,  Next: PEP 3333 Python Web Server Gateway Interface v1 0 1,  Prev: PEP 3147 PYC Repository Directories,  Up: What’s New In Python 3 2

1.12.6 PEP 3149: ABI Version Tagged .so Files
---------------------------------------------

The PYC repository directory allows multiple bytecode cache files to be
co-located.  This PEP implements a similar mechanism for shared object
files by giving them a common directory and distinct names for each
version.

The common directory is “pyshared” and the file names are made distinct
by identifying the Python implementation (such as CPython, PyPy, Jython,
etc.), the major and minor version numbers, and optional build flags
(such as “d” for debug, “m” for pymalloc, “u” for wide-unicode).  For an
arbitrary package “foo”, you may see these files when the distribution
package is installed:

     /usr/share/pyshared/foo.cpython-32m.so
     /usr/share/pyshared/foo.cpython-33md.so

In Python itself, the tags are accessible from functions in the *note
sysconfig: db. module:

     >>> import sysconfig
     >>> sysconfig.get_config_var('SOABI')       # find the version tag
     'cpython-32mu'
     >>> sysconfig.get_config_var('EXT_SUFFIX')  # find the full filename extension
     '.cpython-32mu.so'

See also
........

PEP 3149(1) - ABI Version Tagged .so Files

     PEP written by Barry Warsaw.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3149/


File: python.info,  Node: PEP 3333 Python Web Server Gateway Interface v1 0 1,  Next: Other Language Changes<12>,  Prev: PEP 3149 ABI Version Tagged so Files,  Up: What’s New In Python 3 2

1.12.7 PEP 3333: Python Web Server Gateway Interface v1.0.1
-----------------------------------------------------------

This informational PEP clarifies how bytes/text issues are to be handled
by the WSGI protocol.  The challenge is that string handling in Python 3
is most conveniently handled with the *note str: 44f. type even though
the HTTP protocol is itself bytes oriented.

The PEP differentiates so-called 'native strings' that are used for
request/response headers and metadata versus 'byte strings' which are
used for the bodies of requests and responses.

The 'native strings' are always of type *note str: 44f. but are
restricted to code points between 'U+0000' through 'U+00FF' which are
translatable to bytes using 'Latin-1' encoding.  These strings are used
for the keys and values in the environment dictionary and for response
headers and statuses in the ‘start_response()’ function.  They must
follow RFC 2616(1) with respect to encoding.  That is, they must either
be 'ISO-8859-1' characters or use RFC 2047(2) MIME encoding.

For developers porting WSGI applications from Python 2, here are the
salient points:

   * If the app already used strings for headers in Python 2, no change
     is needed.

   * If instead, the app encoded output headers or decoded input
     headers, then the headers will need to be re-encoded to Latin-1.
     For example, an output header encoded in utf-8 was using
     ‘h.encode('utf-8')’ now needs to convert from bytes to native
     strings using ‘h.encode('utf-8').decode('latin-1')’.

   * Values yielded by an application or sent using the ‘write()’ method
     must be byte strings.  The ‘start_response()’ function and environ
     must use native strings.  The two cannot be mixed.

For server implementers writing CGI-to-WSGI pathways or other CGI-style
protocols, the users must to be able access the environment using native
strings even though the underlying platform may have a different
convention.  To bridge this gap, the *note wsgiref: 118. module has a
new function, *note wsgiref.handlers.read_environ(): 11fd. for
transcoding CGI variables from *note os.environ: 11fe. into native
strings and returning a new dictionary.

See also
........

PEP 3333(3) - Python Web Server Gateway Interface v1.0.1

     PEP written by Phillip Eby.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html

   (2) https://datatracker.ietf.org/doc/html/rfc2047.html

   (3) https://peps.python.org/pep-3333/


File: python.info,  Node: Other Language Changes<12>,  Next: New Improved and Deprecated Modules,  Prev: PEP 3333 Python Web Server Gateway Interface v1 0 1,  Up: What’s New In Python 3 2

1.12.8 Other Language Changes
-----------------------------

Some smaller changes made to the core Python language are:

   * String formatting for *note format(): 622. and *note str.format():
     624. gained new capabilities for the format character '#'.
     Previously, for integers in binary, octal, or hexadecimal, it
     caused the output to be prefixed with ‘0b’, ‘0o’, or ‘0x’
     respectively.  Now it can also handle floats, complex, and Decimal,
     causing the output to always have a decimal point even when no
     digits follow it.

          >>> format(20, '#o')
          '0o24'
          >>> format(12.34, '#5.0f')
          '  12.'

     (Suggested by Mark Dickinson and implemented by Eric Smith in
     bpo-7094(1).)

   * There is also a new *note str.format_map(): e07. method that
     extends the capabilities of the existing *note str.format(): 624.
     method by accepting arbitrary *note mapping: 1200. objects.  This
     new method makes it possible to use string formatting with any of
     Python’s many dictionary-like objects such as *note defaultdict:
     1201, *note Shelf: fd4, *note ConfigParser: 1c8, or *note dbm: 31.
     It is also useful with custom *note dict: 256. subclasses that
     normalize keys before look-up or that supply a *note __missing__():
     1202. method for unknown keys:

          >>> import shelve
          >>> d = shelve.open('tmp.shl')
          >>> 'The {project_name} status is {status} as of {date}'.format_map(d)
          'The testing project status is green as of February 15, 2011'

          >>> class LowerCasedDict(dict):
          ...     def __getitem__(self, key):
          ...         return dict.__getitem__(self, key.lower())
          ...
          >>> lcd = LowerCasedDict(part='widgets', quantity=10)
          >>> 'There are {QUANTITY} {Part} in stock'.format_map(lcd)
          'There are 10 widgets in stock'

          >>> class PlaceholderDict(dict):
          ...     def __missing__(self, key):
          ...         return '<{}>'.format(key)
          ...
          >>> 'Hello {name}, welcome to {location}'.format_map(PlaceholderDict())
          'Hello <name>, welcome to <location>'

     (Suggested by Raymond Hettinger and implemented by Eric Smith in
     bpo-6081(2).)

   * The interpreter can now be started with a quiet option, ‘-q’, to
     prevent the copyright and version information from being displayed
     in the interactive mode.  The option can be introspected using the
     *note sys.flags: 68f. attribute:

          $ python -q
          >>> sys.flags
          sys.flags(debug=0, division_warning=0, inspect=0, interactive=0,
          optimize=0, dont_write_bytecode=0, no_user_site=0, no_site=0,
          ignore_environment=0, verbose=0, bytes_warning=0, quiet=1)

     (Contributed by Marcin Wojdyr in bpo-1772833(3)).

   * The *note hasattr(): 4d5. function works by calling *note
     getattr(): bf0. and detecting whether an exception is raised.  This
     technique allows it to detect methods created dynamically by *note
     __getattr__(): 4d6. or *note __getattribute__(): bf1. which would
     otherwise be absent from the class dictionary.  Formerly, 'hasattr'
     would catch any exception, possibly masking genuine errors.  Now,
     'hasattr' has been tightened to only catch *note AttributeError:
     34e. and let other exceptions pass through:

          >>> class A:
          ...     @property
          ...     def f(self):
          ...         return 1 // 0
          ...
          >>> a = A()
          >>> hasattr(a, 'f')
          Traceback (most recent call last):
            ...
          ZeroDivisionError: integer division or modulo by zero

     (Discovered by Yury Selivanov and fixed by Benjamin Peterson;
     bpo-9666(4).)

   * The *note str(): 44f. of a float or complex number is now the same
     as its *note repr(): 803.  Previously, the ‘str()’ form was shorter
     but that just caused confusion and is no longer needed now that the
     shortest possible ‘repr()’ is displayed by default:

          >>> import math
          >>> repr(math.pi)
          '3.141592653589793'
          >>> str(math.pi)
          '3.141592653589793'

     (Proposed and implemented by Mark Dickinson; bpo-9337(5).)

   * *note memoryview: 2eb. objects now have a *note release(): 1203.
     method and they also now support the context management protocol.
     This allows timely release of any resources that were acquired when
     requesting a buffer from the original object.

          >>> with memoryview(b'abcdefgh') as v:
          ...     print(v.tolist())
          [97, 98, 99, 100, 101, 102, 103, 104]

     (Added by Antoine Pitrou; bpo-9757(6).)

   * Previously it was illegal to delete a name from the local namespace
     if it occurs as a free variable in a nested block:

          def outer(x):
              def inner():
                  return x
              inner()
              del x

     This is now allowed.  Remember that the target of an *note except:
     18b. clause is cleared, so this code which used to work with Python
     2.6, raised a *note SyntaxError: 18d. with Python 3.1 and now works
     again:

          def f():
              def print_error():
                  print(e)
              try:
                  something
              except Exception as e:
                  print_error()
                  # implicit "del e" here

     (See bpo-4617(7).)

   * *note Struct sequence types: 1204. are now subclasses of tuple.
     This means that C structures like those returned by *note
     os.stat(): 4a3, *note time.gmtime(): 1205, and *note
     sys.version_info: 6a3. now work like a *note named tuple: 651. and
     now work with functions and methods that expect a tuple as an
     argument.  This is a big step forward in making the C structures as
     flexible as their pure Python counterparts:

          >>> import sys
          >>> isinstance(sys.version_info, tuple)
          True
          >>> 'Version %d.%d.%d %s(%d)' % sys.version_info
          'Version 3.2.0 final(0)'

     (Suggested by Arfrever Frehtes Taifersar Arahesis and implemented
     by Benjamin Peterson in bpo-8413(8).)

   * Warnings are now easier to control using the *note PYTHONWARNINGS:
     bc8. environment variable as an alternative to using ‘-W’ at the
     command line:

          $ export PYTHONWARNINGS='ignore::RuntimeWarning::,once::UnicodeWarning::'

     (Suggested by Barry Warsaw and implemented by Philip Jenvey in
     bpo-7301(9).)

   * A new warning category, *note ResourceWarning: 244, has been added.
     It is emitted when potential issues with resource consumption or
     cleanup are detected.  It is silenced by default in normal release
     builds but can be enabled through the means provided by the *note
     warnings: 112. module, or on the command line.

     A *note ResourceWarning: 244. is issued at interpreter shutdown if
     the *note gc.garbage: 1206. list isn’t empty, and if *note
     gc.DEBUG_UNCOLLECTABLE: 1207. is set, all uncollectable objects are
     printed.  This is meant to make the programmer aware that their
     code contains object finalization issues.

     A *note ResourceWarning: 244. is also issued when a *note file
     object: 1208. is destroyed without having been explicitly closed.
     While the deallocator for such object ensures it closes the
     underlying operating system resource (usually, a file descriptor),
     the delay in deallocating the object could produce various issues,
     especially under Windows.  Here is an example of enabling the
     warning from the command line:

          $ python -q -Wdefault
          >>> f = open("foo", "wb")
          >>> del f
          __main__:1: ResourceWarning: unclosed file <_io.BufferedWriter name='foo'>

     (Added by Antoine Pitrou and Georg Brandl in bpo-10093(10) and
     bpo-477863(11).)

   * *note range: 94d. objects now support 'index' and 'count' methods.
     This is part of an effort to make more objects fully implement the
     *note collections.Sequence: 1209. *note abstract base class: 11fa.
     As a result, the language will have a more uniform API. In
     addition, ‘range’ objects now support slicing and negative indices,
     even with values larger than *note sys.maxsize: 120a.  This makes
     'range' more interoperable with lists:

          >>> range(0, 100, 2).count(10)
          1
          >>> range(0, 100, 2).index(10)
          5
          >>> range(0, 100, 2)[5]
          10
          >>> range(0, 100, 2)[0:5]
          range(0, 10, 2)

     (Contributed by Daniel Stutzbach in bpo-9213(12), by Alexander
     Belopolsky in bpo-2690(13), and by Nick Coghlan in bpo-10889(14).)

   * The *note callable(): 120b. builtin function from Py2.x was
     resurrected.  It provides a concise, readable alternative to using
     an *note abstract base class: 11fa. in an expression like
     ‘isinstance(x, collections.Callable)’:

          >>> callable(max)
          True
          >>> callable(20)
          False

     (See bpo-10518(15).)

   * Python’s import mechanism can now load modules installed in
     directories with non-ASCII characters in the path name.  This
     solved an aggravating problem with home directories for users with
     non-ASCII characters in their usernames.

     (Required extensive work by Victor Stinner in bpo-9425(16).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7094

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6081

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1772833

   (4) https://bugs.python.org/issue?@action=redirect&bpo=9666

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9337

   (6) https://bugs.python.org/issue?@action=redirect&bpo=9757

   (7) https://bugs.python.org/issue?@action=redirect&bpo=4617

   (8) https://bugs.python.org/issue?@action=redirect&bpo=8413

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7301

   (10) https://bugs.python.org/issue?@action=redirect&bpo=10093

   (11) https://bugs.python.org/issue?@action=redirect&bpo=477863

   (12) https://bugs.python.org/issue?@action=redirect&bpo=9213

   (13) https://bugs.python.org/issue?@action=redirect&bpo=2690

   (14) https://bugs.python.org/issue?@action=redirect&bpo=10889

   (15) https://bugs.python.org/issue?@action=redirect&bpo=10518

   (16) https://bugs.python.org/issue?@action=redirect&bpo=9425


File: python.info,  Node: New Improved and Deprecated Modules,  Next: Multi-threading,  Prev: Other Language Changes<12>,  Up: What’s New In Python 3 2

1.12.9 New, Improved, and Deprecated Modules
--------------------------------------------

Python’s standard library has undergone significant maintenance efforts
and quality improvements.

The biggest news for Python 3.2 is that the *note email: 3b. package,
*note mailbox: 8b. module, and ‘nntplib’ modules now work correctly with
the bytes/text model in Python 3.  For the first time, there is correct
handling of messages with mixed encodings.

Throughout the standard library, there has been more careful attention
to encodings and text versus bytes issues.  In particular, interactions
with the operating system are now better able to exchange non-ASCII data
using the Windows MBCS encoding, locale-aware encodings, or UTF-8.

Another significant win is the addition of substantially better support
for 'SSL' connections and security certificates.

In addition, more classes now implement a *note context manager: 5d7. to
support convenient and reliable resource clean-up using a *note with:
5d5. statement.

* Menu:

* email: email<6>.
* elementtree::
* functools: functools<7>.
* itertools: itertools<7>.
* collections: collections<8>.
* threading: threading<9>.
* datetime and time::
* math: math<10>.
* abc: abc<3>.
* io: io<7>.
* reprlib::
* logging: logging<8>.
* csv: csv<4>.
* contextlib: contextlib<8>.
* decimal and fractions::
* ftp::
* popen::
* select: select<3>.
* gzip and zipfile::
* tarfile: tarfile<10>.
* hashlib: hashlib<7>.
* ast: ast<5>.
* os: os<13>.
* shutil: shutil<8>.
* sqlite3: sqlite3<11>.
* html: html<3>.
* socket: socket<11>.
* ssl: ssl<12>.
* nntp::
* certificates::
* imaplib: imaplib<4>.
* http.client: http client<4>.
* unittest: unittest<11>.
* random: random<5>.
* poplib: poplib<4>.
* asyncore: asyncore<2>.
* tempfile: tempfile<5>.
* inspect: inspect<10>.
* pydoc: pydoc<6>.
* dis: dis<5>.
* dbm: dbm<7>.
* ctypes: ctypes<3>.
* site: site<4>.
* sysconfig: sysconfig<3>.
* pdb: pdb<8>.
* configparser: configparser<5>.
* urllib.parse: urllib parse<6>.
* mailbox::
* turtledemo::


File: python.info,  Node: email<6>,  Next: elementtree,  Up: New Improved and Deprecated Modules

1.12.9.1 email
..............

The usability of the *note email: 3b. package in Python 3 has been
mostly fixed by the extensive efforts of R. David Murray.  The problem
was that emails are typically read and stored in the form of *note
bytes: 1c2. rather than *note str: 44f. text, and they may contain
multiple encodings within a single email.  So, the email package had to
be extended to parse and generate email messages in bytes format.

   * New functions *note message_from_bytes(): 120e. and *note
     message_from_binary_file(): 120f, and new classes *note
     BytesFeedParser: 1210. and *note BytesParser: 1211. allow binary
     message data to be parsed into model objects.

   * Given bytes input to the model, *note get_payload(): 1212. will by
     default decode a message body that has a
     ‘Content-Transfer-Encoding’ of '8bit' using the charset specified
     in the MIME headers and return the resulting string.

   * Given bytes input to the model, *note Generator: 1213. will convert
     message bodies that have a ‘Content-Transfer-Encoding’ of '8bit' to
     instead have a '7bit' ‘Content-Transfer-Encoding’.

     Headers with unencoded non-ASCII bytes are deemed to be RFC
     2047(1)-encoded using the 'unknown-8bit' character set.

   * A new class *note BytesGenerator: 1214. produces bytes as output,
     preserving any unchanged non-ASCII data that was present in the
     input used to build the model, including message bodies with a
     ‘Content-Transfer-Encoding’ of '8bit'.

   * The *note smtplib: ca. *note SMTP: 937. class now accepts a byte
     string for the 'msg' argument to the *note sendmail(): e8d. method,
     and a new method, *note send_message(): e8e. accepts a *note
     Message: 27c. object and can optionally obtain the 'from_addr' and
     'to_addrs' addresses directly from the object.

(Proposed and implemented by R. David Murray, bpo-4661(2) and
bpo-10321(3).)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2047.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4661

   (3) https://bugs.python.org/issue?@action=redirect&bpo=10321


File: python.info,  Node: elementtree,  Next: functools<7>,  Prev: email<6>,  Up: New Improved and Deprecated Modules

1.12.9.2 elementtree
....................

The *note xml.etree.ElementTree: 125. package and its
‘xml.etree.cElementTree’ counterpart have been updated to version 1.3.

Several new and useful functions and methods have been added:

   * *note xml.etree.ElementTree.fromstringlist(): 1216. which builds an
     XML document from a sequence of fragments

   * *note xml.etree.ElementTree.register_namespace(): 1217. for
     registering a global namespace prefix

   * *note xml.etree.ElementTree.tostringlist(): 1031. for string
     representation including all sublists

   * *note xml.etree.ElementTree.Element.extend(): 1218. for appending a
     sequence of zero or more elements

   * *note xml.etree.ElementTree.Element.iterfind(): 1219. searches an
     element and subelements

   * *note xml.etree.ElementTree.Element.itertext(): 121a. creates a
     text iterator over an element and its subelements

   * *note xml.etree.ElementTree.TreeBuilder.end(): 121b. closes the
     current element

   * *note xml.etree.ElementTree.TreeBuilder.doctype(): aac. handles a
     doctype declaration

Two methods have been deprecated:

   * ‘xml.etree.ElementTree.getchildren()’ use ‘list(elem)’ instead.

   * ‘xml.etree.ElementTree.getiterator()’ use ‘Element.iter’ instead.

For details of the update, see Introducing ElementTree(1) on Fredrik
Lundh’s website.

(Contributed by Florent Xicluna and Fredrik Lundh, bpo-6472(2).)

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20200703234532/http://effbot.org/zone/elementtree-13-intro.htm

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6472


File: python.info,  Node: functools<7>,  Next: itertools<7>,  Prev: elementtree,  Up: New Improved and Deprecated Modules

1.12.9.3 functools
..................

   * The *note functools: 5f. module includes a new decorator for
     caching function calls.  *note functools.lru_cache(): 9fa. can save
     repeated queries to an external resource whenever the results are
     expected to be the same.

     For example, adding a caching decorator to a database query
     function can save database accesses for popular searches:

          >>> import functools
          >>> @functools.lru_cache(maxsize=300)
          ... def get_phone_number(name):
          ...     c = conn.cursor()
          ...     c.execute('SELECT phonenumber FROM phonelist WHERE name=?', (name,))
          ...     return c.fetchone()[0]

          >>> for name in user_requests:
          ...     get_phone_number(name)        # cached lookup

     To help with choosing an effective cache size, the wrapped function
     is instrumented for tracking cache statistics:

          >>> get_phone_number.cache_info()
          CacheInfo(hits=4805, misses=980, maxsize=300, currsize=300)

     If the phonelist table gets updated, the outdated contents of the
     cache can be cleared with:

          >>> get_phone_number.cache_clear()

     (Contributed by Raymond Hettinger and incorporating design ideas
     from Jim Baker, Miki Tebeka, and Nick Coghlan; see recipe
     498245(1), recipe 577479(2), bpo-10586(3), and bpo-10593(4).)

   * The *note functools.wraps(): f96. decorator now adds a
     ‘__wrapped__’ attribute pointing to the original callable function.
     This allows wrapped functions to be introspected.  It also copies
     *note __annotations__: 121d. if defined.  And now it also
     gracefully skips over missing attributes such as *note __doc__:
     121e. which might not be defined for the wrapped callable.

     In the above example, the cache can be removed by recovering the
     original function:

          >>> get_phone_number = get_phone_number.__wrapped__    # uncached function

     (By Nick Coghlan and Terrence Cole; bpo-9567(5), bpo-3445(6), and
     bpo-8814(7).)

   * To help write classes with rich comparison methods, a new decorator
     *note functools.total_ordering(): f7a. will use existing equality
     and inequality methods to fill in the remaining methods.

     For example, supplying '__eq__' and '__lt__' will enable *note
     total_ordering(): f7a. to fill-in '__le__', '__gt__' and '__ge__':

          @total_ordering
          class Student:
              def __eq__(self, other):
                  return ((self.lastname.lower(), self.firstname.lower()) ==
                          (other.lastname.lower(), other.firstname.lower()))

              def __lt__(self, other):
                  return ((self.lastname.lower(), self.firstname.lower()) <
                          (other.lastname.lower(), other.firstname.lower()))

     With the 'total_ordering' decorator, the remaining comparison
     methods are filled in automatically.

     (Contributed by Raymond Hettinger.)

   * To aid in porting programs from Python 2, the *note
     functools.cmp_to_key(): 121f. function converts an old-style
     comparison function to modern *note key function: e37.:

          >>> # locale-aware sort order
          >>> sorted(iterable, key=cmp_to_key(locale.strcoll))

     For sorting examples and a brief sorting tutorial, see the Sorting
     HowTo(8) tutorial.

     (Contributed by Raymond Hettinger.)

   ---------- Footnotes ----------

   (1) 
https://code.activestate.com/recipes/498245-lru-and-lfu-cache-decorators/

   (2) 
https://code.activestate.com/recipes/577479-simple-caching-decorator/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=10586

   (4) https://bugs.python.org/issue?@action=redirect&bpo=10593

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9567

   (6) https://bugs.python.org/issue?@action=redirect&bpo=3445

   (7) https://bugs.python.org/issue?@action=redirect&bpo=8814

   (8) https://wiki.python.org/moin/HowTo/Sorting/


File: python.info,  Node: itertools<7>,  Next: collections<8>,  Prev: functools<7>,  Up: New Improved and Deprecated Modules

1.12.9.4 itertools
..................

   * The *note itertools: 81. module has a new *note accumulate(): a08.
     function modeled on APL’s 'scan' operator and Numpy’s 'accumulate'
     function:

          >>> from itertools import accumulate
          >>> list(accumulate([8, 2, 50]))
          [8, 10, 60]

          >>> prob_dist = [0.1, 0.4, 0.2, 0.3]
          >>> list(accumulate(prob_dist))      # cumulative probability distribution
          [0.1, 0.5, 0.7, 1.0]

     For an example using *note accumulate(): a08, see the *note
     examples for the random module: 1221.

     (Contributed by Raymond Hettinger and incorporating design
     suggestions from Mark Dickinson.)


File: python.info,  Node: collections<8>,  Next: threading<9>,  Prev: itertools<7>,  Up: New Improved and Deprecated Modules

1.12.9.5 collections
....................

   * The *note collections.Counter: 10d5. class now has two forms of
     in-place subtraction, the existing '-=' operator for saturating
     subtraction(1) and the new *note subtract(): 1223. method for
     regular subtraction.  The former is suitable for multisets(2) which
     only have positive counts, and the latter is more suitable for use
     cases that allow negative counts:

          >>> from collections import Counter
          >>> tally = Counter(dogs=5, cats=3)
          >>> tally -= Counter(dogs=2, cats=8)    # saturating subtraction
          >>> tally
          Counter({'dogs': 3})

          >>> tally = Counter(dogs=5, cats=3)
          >>> tally.subtract(dogs=2, cats=8)      # regular subtraction
          >>> tally
          Counter({'dogs': 3, 'cats': -5})

     (Contributed by Raymond Hettinger.)

   * The *note collections.OrderedDict: 5de. class has a new method
     *note move_to_end(): 1224. which takes an existing key and moves it
     to either the first or last position in the ordered sequence.

     The default is to move an item to the last position.  This is
     equivalent of renewing an entry with ‘od[k] = od.pop(k)’.

     A fast move-to-end operation is useful for resequencing entries.
     For example, an ordered dictionary can be used to track order of
     access by aging entries from the oldest to the most recently
     accessed.

          >>> from collections import OrderedDict
          >>> d = OrderedDict.fromkeys(['a', 'b', 'X', 'd', 'e'])
          >>> list(d)
          ['a', 'b', 'X', 'd', 'e']
          >>> d.move_to_end('X')
          >>> list(d)
          ['a', 'b', 'd', 'e', 'X']

     (Contributed by Raymond Hettinger.)

   * The *note collections.deque: 5df. class grew two new methods *note
     count(): 1225. and *note reverse(): 1226. that make them more
     substitutable for *note list: 614. objects:

          >>> from collections import deque
          >>> d = deque('simsalabim')
          >>> d.count('s')
          2
          >>> d.reverse()
          >>> d
          deque(['m', 'i', 'b', 'a', 'l', 'a', 's', 'm', 'i', 's'])

     (Contributed by Raymond Hettinger.)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Saturation_arithmetic

   (2) https://en.wikipedia.org/wiki/Multiset


File: python.info,  Node: threading<9>,  Next: datetime and time,  Prev: collections<8>,  Up: New Improved and Deprecated Modules

1.12.9.6 threading
..................

The *note threading: ed. module has a new *note Barrier: 1228.
synchronization class for making multiple threads wait until all of them
have reached a common barrier point.  Barriers are useful for making
sure that a task with multiple preconditions does not run until all of
the predecessor tasks are complete.

Barriers can work with an arbitrary number of threads.  This is a
generalization of a Rendezvous(1) which is defined for only two threads.

Implemented as a two-phase cyclic barrier, *note Barrier: 1228. objects
are suitable for use in loops.  The separate 'filling' and 'draining'
phases assure that all threads get released (drained) before any one of
them can loop back and re-enter the barrier.  The barrier fully resets
after each cycle.

Example of using barriers:

     from threading import Barrier, Thread

     def get_votes(site):
         ballots = conduct_election(site)
         all_polls_closed.wait()        # do not count until all polls are closed
         totals = summarize(ballots)
         publish(site, totals)

     all_polls_closed = Barrier(len(sites))
     for site in sites:
         Thread(target=get_votes, args=(site,)).start()

In this example, the barrier enforces a rule that votes cannot be
counted at any polling site until all polls are closed.  Notice how a
solution with a barrier is similar to one with *note
threading.Thread.join(): 1229, but the threads stay alive and continue
to do work (summarizing ballots) after the barrier point is crossed.

If any of the predecessor tasks can hang or be delayed, a barrier can be
created with an optional 'timeout' parameter.  Then if the timeout
period elapses before all the predecessor tasks reach the barrier point,
all waiting threads are released and a *note BrokenBarrierError: 122a.
exception is raised:

     def get_votes(site):
         ballots = conduct_election(site)
         try:
             all_polls_closed.wait(timeout=midnight - time.now())
         except BrokenBarrierError:
             lockbox = seal_ballots(ballots)
             queue.put(lockbox)
         else:
             totals = summarize(ballots)
             publish(site, totals)

In this example, the barrier enforces a more robust rule.  If some
election sites do not finish before midnight, the barrier times-out and
the ballots are sealed and deposited in a queue for later handling.

See Barrier Synchronization Patterns(2) for more examples of how
barriers can be used in parallel computing.  Also, there is a simple but
thorough explanation of barriers in The Little Book of Semaphores(3),
'section 3.6'.

(Contributed by Kristján Valur Jónsson with an API review by Jeffrey
Yasskin in bpo-8777(4).)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Synchronous_rendezvous

   (2) 
https://osl.cs.illinois.edu/media/papers/karmani-2009-barrier_synchronization_pattern.pdf

   (3) https://greenteapress.com/semaphores/LittleBookOfSemaphores.pdf

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8777


File: python.info,  Node: datetime and time,  Next: math<10>,  Prev: threading<9>,  Up: New Improved and Deprecated Modules

1.12.9.7 datetime and time
..........................

   * The *note datetime: 30. module has a new type *note timezone: 1103.
     that implements the *note tzinfo: 5e1. interface by returning a
     fixed UTC offset and timezone name.  This makes it easier to create
     timezone-aware datetime objects:

          >>> import datetime as dt

          >>> dt.datetime.now(dt.timezone.utc)
          datetime.datetime(2010, 12, 8, 21, 4, 2, 923754, tzinfo=datetime.timezone.utc)

          >>> dt.datetime.strptime("01/01/2000 12:00 +0000", "%m/%d/%Y %H:%M %z")
          datetime.datetime(2000, 1, 1, 12, 0, tzinfo=datetime.timezone.utc)

   * Also, *note timedelta: 9da. objects can now be multiplied by *note
     float: 2f7. and divided by ‘float’ and *note int: 257. objects.
     And ‘timedelta’ objects can now divide one another.

   * The *note datetime.date.strftime(): cb6. method is no longer
     restricted to years after 1900.  The new supported year range is
     from 1000 to 9999 inclusive.

   * Whenever a two-digit year is used in a time tuple, the
     interpretation has been governed by ‘time.accept2dyear’.  The
     default is ‘True’ which means that for a two-digit year, the
     century is guessed according to the POSIX rules governing the ‘%y’
     strptime format.

     Starting with Py3.2, use of the century guessing heuristic will
     emit a *note DeprecationWarning: 1a5.  Instead, it is recommended
     that ‘time.accept2dyear’ be set to ‘False’ so that large date
     ranges can be used without guesswork:

          >>> import time, warnings
          >>> warnings.resetwarnings()      # remove the default warning filters

          >>> time.accept2dyear = True      # guess whether 11 means 11 or 2011
          >>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
          Warning (from warnings module):
            ...
          DeprecationWarning: Century info guessed for a 2-digit year.
          'Fri Jan  1 12:34:56 2011'

          >>> time.accept2dyear = False     # use the full range of allowable dates
          >>> time.asctime((11, 1, 1, 12, 34, 56, 4, 1, 0))
          'Fri Jan  1 12:34:56 11'

     Several functions now have significantly expanded date ranges.
     When ‘time.accept2dyear’ is false, the *note time.asctime(): 122c.
     function will accept any year that fits in a C int, while the *note
     time.mktime(): 122d. and *note time.strftime(): 122e. functions
     will accept the full range supported by the corresponding operating
     system functions.

(Contributed by Alexander Belopolsky and Victor Stinner in
bpo-1289118(1), bpo-5094(2), bpo-6641(3), bpo-2706(4), bpo-1777412(5),
bpo-8013(6), and bpo-10827(7).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1289118

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5094

   (3) https://bugs.python.org/issue?@action=redirect&bpo=6641

   (4) https://bugs.python.org/issue?@action=redirect&bpo=2706

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1777412

   (6) https://bugs.python.org/issue?@action=redirect&bpo=8013

   (7) https://bugs.python.org/issue?@action=redirect&bpo=10827


File: python.info,  Node: math<10>,  Next: abc<3>,  Prev: datetime and time,  Up: New Improved and Deprecated Modules

1.12.9.8 math
.............

The *note math: 8e. module has been updated with six new functions
inspired by the C99 standard.

The *note isfinite(): 1230. function provides a reliable and fast way to
detect special values.  It returns ‘True’ for regular numbers and
‘False’ for 'Nan' or 'Infinity':

     >>> from math import isfinite
     >>> [isfinite(x) for x in (123, 4.56, float('Nan'), float('Inf'))]
     [True, True, False, False]

The *note expm1(): 1231. function computes ‘e**x-1’ for small values of
'x' without incurring the loss of precision that usually accompanies the
subtraction of nearly equal quantities:

     >>> from math import expm1
     >>> expm1(0.013671875)   # more accurate way to compute e**x-1 for a small x
     0.013765762467652909

The *note erf(): bf9. function computes a probability integral or
Gaussian error function(1).  The complementary error function, *note
erfc(): bfa, is ‘1 - erf(x)’:

     >>> from math import erf, erfc, sqrt
     >>> erf(1.0/sqrt(2.0))   # portion of normal distribution within 1 standard deviation
     0.682689492137086
     >>> erfc(1.0/sqrt(2.0))  # portion of normal distribution outside 1 standard deviation
     0.31731050786291404
     >>> erf(1.0/sqrt(2.0)) + erfc(1.0/sqrt(2.0))
     1.0

The *note gamma(): 1232. function is a continuous extension of the
factorial function.  See ‘https://en.wikipedia.org/wiki/Gamma_function’
for details.  Because the function is related to factorials, it grows
large even for small values of 'x', so there is also a *note lgamma():
1233. function for computing the natural logarithm of the gamma
function:

     >>> from math import gamma, lgamma
     >>> gamma(7.0)           # six factorial
     720.0
     >>> lgamma(801.0)        # log(800 factorial)
     4551.950730698041

(Contributed by Mark Dickinson.)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Error_function


File: python.info,  Node: abc<3>,  Next: io<7>,  Prev: math<10>,  Up: New Improved and Deprecated Modules

1.12.9.9 abc
............

The *note abc: 4. module now supports *note abstractclassmethod(): 10ca.
and *note abstractstaticmethod(): 10cb.

These tools make it possible to define an *note abstract base class:
11fa. that requires a particular *note classmethod(): 166. or *note
staticmethod(): 419. to be implemented:

     class Temperature(metaclass=abc.ABCMeta):
         @abc.abstractclassmethod
         def from_fahrenheit(cls, t):
             ...
         @abc.abstractclassmethod
         def from_celsius(cls, t):
             ...

(Patch submitted by Daniel Urban; bpo-5867(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5867


File: python.info,  Node: io<7>,  Next: reprlib,  Prev: abc<3>,  Up: New Improved and Deprecated Modules

1.12.9.10 io
............

The *note io.BytesIO: ed8. has a new method, *note getbuffer(): 1236,
which provides functionality similar to *note memoryview(): 2eb.  It
creates an editable view of the data without making a copy.  The
buffer’s random access and support for slice notation are well-suited to
in-place editing:

     >>> REC_LEN, LOC_START, LOC_LEN = 34, 7, 11

     >>> def change_location(buffer, record_number, location):
     ...     start = record_number * REC_LEN + LOC_START
     ...     buffer[start: start+LOC_LEN] = location

     >>> import io

     >>> byte_stream = io.BytesIO(
     ...     b'G3805  storeroom  Main chassis    '
     ...     b'X7899  shipping   Reserve cog     '
     ...     b'L6988  receiving  Primary sprocket'
     ... )
     >>> buffer = byte_stream.getbuffer()
     >>> change_location(buffer, 1, b'warehouse  ')
     >>> change_location(buffer, 0, b'showroom   ')
     >>> print(byte_stream.getvalue())
     b'G3805  showroom   Main chassis    '
     b'X7899  warehouse  Reserve cog     '
     b'L6988  receiving  Primary sprocket'

(Contributed by Antoine Pitrou in bpo-5506(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5506


File: python.info,  Node: reprlib,  Next: logging<8>,  Prev: io<7>,  Up: New Improved and Deprecated Modules

1.12.9.11 reprlib
.................

When writing a *note __repr__(): 61f. method for a custom container, it
is easy to forget to handle the case where a member refers back to the
container itself.  Python’s builtin objects such as *note list: 614. and
*note set: 5dc. handle self-reference by displaying “…” in the recursive
part of the representation string.

To help write such *note __repr__(): 61f. methods, the *note reprlib:
bb. module has a new decorator, *note recursive_repr(): 1238, for
detecting recursive calls to ‘__repr__()’ and substituting a placeholder
string instead:

     >>> class MyList(list):
     ...     @recursive_repr()
     ...     def __repr__(self):
     ...         return '<' + '|'.join(map(repr, self)) + '>'
     ...
     >>> m = MyList('abc')
     >>> m.append(m)
     >>> m.append('x')
     >>> print(m)
     <'a'|'b'|'c'|...|'x'>

(Contributed by Raymond Hettinger in bpo-9826(1) and bpo-9840(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9826

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9840


File: python.info,  Node: logging<8>,  Next: csv<4>,  Prev: reprlib,  Up: New Improved and Deprecated Modules

1.12.9.12 logging
.................

In addition to dictionary-based configuration described above, the *note
logging: 87. package has many other improvements.

The logging documentation has been augmented by a *note basic tutorial:
123a, an *note advanced tutorial: 123b, and a *note cookbook: 123c. of
logging recipes.  These documents are the fastest way to learn about
logging.

The *note logging.basicConfig(): a0b. set-up function gained a 'style'
argument to support three different types of string formatting.  It
defaults to “%” for traditional %-formatting, can be set to “{” for the
new *note str.format(): 624. style, or can be set to “$” for the
shell-style formatting provided by *note string.Template: 68a.  The
following three configurations are equivalent:

     >>> from logging import basicConfig
     >>> basicConfig(style='%', format="%(name)s -> %(levelname)s: %(message)s")
     >>> basicConfig(style='{', format="{name} -> {levelname} {message}")
     >>> basicConfig(style='$', format="$name -> $levelname: $message")

If no configuration is set-up before a logging event occurs, there is
now a default configuration using a *note StreamHandler: 123d. directed
to *note sys.stderr: 943. for events of ‘WARNING’ level or higher.
Formerly, an event occurring before a configuration was set-up would
either raise an exception or silently drop the event depending on the
value of *note logging.raiseExceptions: 123e.  The new default handler
is stored in *note logging.lastResort: 123f.

The use of filters has been simplified.  Instead of creating a *note
Filter: 1240. object, the predicate can be any Python callable that
returns ‘True’ or ‘False’.

There were a number of other improvements that add flexibility and
simplify configuration.  See the module documentation for a full listing
of changes in Python 3.2.


File: python.info,  Node: csv<4>,  Next: contextlib<8>,  Prev: logging<8>,  Up: New Improved and Deprecated Modules

1.12.9.13 csv
.............

The *note csv: 29. module now supports a new dialect, *note
unix_dialect: 1242, which applies quoting for all fields and a
traditional Unix style with ‘'\n'’ as the line terminator.  The
registered dialect name is ‘unix’.

The *note csv.DictWriter: 1243. has a new method, *note writeheader():
1244. for writing-out an initial row to document the field names:

     >>> import csv, sys
     >>> w = csv.DictWriter(sys.stdout, ['name', 'dept'], dialect='unix')
     >>> w.writeheader()
     "name","dept"
     >>> w.writerows([
     ...     {'name': 'tom', 'dept': 'accounting'},
     ...     {'name': 'susan', 'dept': 'Salesl'}])
     "tom","accounting"
     "susan","sales"

(New dialect suggested by Jay Talbot in bpo-5975(1), and the new method
suggested by Ed Abraham in bpo-1537721(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5975

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1537721


File: python.info,  Node: contextlib<8>,  Next: decimal and fractions,  Prev: csv<4>,  Up: New Improved and Deprecated Modules

1.12.9.14 contextlib
....................

There is a new and slightly mind-blowing tool *note ContextDecorator:
1246. that is helpful for creating a *note context manager: 5d7. that
does double duty as a function decorator.

As a convenience, this new functionality is used by *note
contextmanager(): 1247. so that no extra effort is needed to support
both roles.

The basic idea is that both context managers and function decorators can
be used for pre-action and post-action wrappers.  Context managers wrap
a group of statements using a *note with: 5d5. statement, and function
decorators wrap a group of statements enclosed in a function.  So,
occasionally there is a need to write a pre-action or post-action
wrapper that can be used in either role.

For example, it is sometimes useful to wrap functions or groups of
statements with a logger that can track the time of entry and time of
exit.  Rather than writing both a function decorator and a context
manager for the task, the *note contextmanager(): 1247. provides both
capabilities in a single definition:

     from contextlib import contextmanager
     import logging

     logging.basicConfig(level=logging.INFO)

     @contextmanager
     def track_entry_and_exit(name):
         logging.info('Entering: %s', name)
         yield
         logging.info('Exiting: %s', name)

Formerly, this would have only been usable as a context manager:

     with track_entry_and_exit('widget loader'):
         print('Some time consuming activity goes here')
         load_widget()

Now, it can be used as a decorator as well:

     @track_entry_and_exit('widget loader')
     def activity():
         print('Some time consuming activity goes here')
         load_widget()

Trying to fulfill two roles at once places some limitations on the
technique.  Context managers normally have the flexibility to return an
argument usable by a *note with: 5d5. statement, but there is no
parallel for function decorators.

In the above example, there is not a clean way for the
'track_entry_and_exit' context manager to return a logging instance for
use in the body of enclosed statements.

(Contributed by Michael Foord in bpo-9110(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9110


File: python.info,  Node: decimal and fractions,  Next: ftp,  Prev: contextlib<8>,  Up: New Improved and Deprecated Modules

1.12.9.15 decimal and fractions
...............................

Mark Dickinson crafted an elegant and efficient scheme for assuring that
different numeric datatypes will have the same hash value whenever their
actual values are equal (bpo-8188(1)):

     assert hash(Fraction(3, 2)) == hash(1.5) == \
            hash(Decimal("1.5")) == hash(complex(1.5, 0))

Some of the hashing details are exposed through a new attribute, *note
sys.hash_info: 103a, which describes the bit width of the hash value,
the prime modulus, the hash values for 'infinity' and 'nan', and the
multiplier used for the imaginary part of a number:

     >>> sys.hash_info
     sys.hash_info(width=64, modulus=2305843009213693951, inf=314159, nan=0, imag=1000003)

An early decision to limit the interoperability of various numeric types
has been relaxed.  It is still unsupported (and ill-advised) to have
implicit mixing in arithmetic expressions such as ‘Decimal('1.1') +
float('1.1')’ because the latter loses information in the process of
constructing the binary float.  However, since existing floating-point
value can be converted losslessly to either a decimal or rational
representation, it makes sense to add them to the constructor and to
support mixed-type comparisons.

   * The *note decimal.Decimal: 29d. constructor now accepts *note
     float: 2f7. objects directly so there in no longer a need to use
     the *note from_float(): 1249. method (bpo-8257(2)).

   * Mixed type comparisons are now fully supported so that *note
     Decimal: 29d. objects can be directly compared with *note float:
     2f7. and *note fractions.Fraction: 1e7. (bpo-2531(3) and
     bpo-8188(4)).

Similar changes were made to *note fractions.Fraction: 1e7. so that the
*note from_float(): 124a. and *note from_decimal(): 124b. methods are no
longer needed (bpo-8294(5)):

     >>> from decimal import Decimal
     >>> from fractions import Fraction
     >>> Decimal(1.1)
     Decimal('1.100000000000000088817841970012523233890533447265625')
     >>> Fraction(1.1)
     Fraction(2476979795053773, 2251799813685248)

Another useful change for the *note decimal: 36. module is that the
*note Context.clamp: 11e2. attribute is now public.  This is useful in
creating contexts that correspond to the decimal interchange formats
specified in IEEE 754 (see bpo-8540(6)).

(Contributed by Mark Dickinson and Raymond Hettinger.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8188

   (2) https://bugs.python.org/issue?@action=redirect&bpo=8257

   (3) https://bugs.python.org/issue?@action=redirect&bpo=2531

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8188

   (5) https://bugs.python.org/issue?@action=redirect&bpo=8294

   (6) https://bugs.python.org/issue?@action=redirect&bpo=8540


File: python.info,  Node: ftp,  Next: popen,  Prev: decimal and fractions,  Up: New Improved and Deprecated Modules

1.12.9.16 ftp
.............

The *note ftplib.FTP: 903. class now supports the context management
protocol to unconditionally consume *note socket.error: 1093. exceptions
and to close the FTP connection when done:

     >>> from ftplib import FTP
     >>> with FTP("ftp1.at.proftpd.org") as ftp:
             ftp.login()
             ftp.dir()

     '230 Anonymous login ok, restrictions apply.'
     dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 .
     dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 ..
     dr-xr-xr-x   5 ftp      ftp          4096 May  6 10:43 CentOS
     dr-xr-xr-x   3 ftp      ftp            18 Jul 10  2008 Fedora

Other file-like objects such as *note mmap.mmap: 20b. and *note
fileinput.input(): 805. also grew auto-closing context managers:

     with fileinput.input(files=('log1.txt', 'log2.txt')) as f:
         for line in f:
             process(line)

(Contributed by Tarek Ziadé and Giampaolo Rodolà in bpo-4972(1), and by
Georg Brandl in bpo-8046(2) and bpo-1286(3).)

The *note FTP_TLS: 904. class now accepts a 'context' parameter, which
is a *note ssl.SSLContext: 294. object allowing bundling SSL
configuration options, certificates and private keys into a single
(potentially long-lived) structure.

(Contributed by Giampaolo Rodolà; bpo-8806(4).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4972

   (2) https://bugs.python.org/issue?@action=redirect&bpo=8046

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1286

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8806


File: python.info,  Node: popen,  Next: select<3>,  Prev: ftp,  Up: New Improved and Deprecated Modules

1.12.9.17 popen
...............

The *note os.popen(): a96. and *note subprocess.Popen(): 199. functions
now support *note with: 5d5. statements for auto-closing of the file
descriptors.

(Contributed by Antoine Pitrou and Brian Curtin in bpo-7461(1) and
bpo-10554(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7461

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10554


File: python.info,  Node: select<3>,  Next: gzip and zipfile,  Prev: popen,  Up: New Improved and Deprecated Modules

1.12.9.18 select
................

The *note select: c1. module now exposes a new, constant attribute,
*note PIPE_BUF: 124f, which gives the minimum number of bytes which are
guaranteed not to block when *note select.select(): dce. says a pipe is
ready for writing.

     >>> import select
     >>> select.PIPE_BUF
     512

(Available on Unix systems.  Patch by Sébastien Sablé in bpo-9862(1))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9862


File: python.info,  Node: gzip and zipfile,  Next: tarfile<10>,  Prev: select<3>,  Up: New Improved and Deprecated Modules

1.12.9.19 gzip and zipfile
..........................

*note gzip.GzipFile: 41d. now implements the *note io.BufferedIOBase:
697. *note abstract base class: 11fa. (except for ‘truncate()’).  It
also has a *note peek(): 1251. method and supports unseekable as well as
zero-padded file objects.

The *note gzip: 67. module also gains the *note compress(): 641. and
*note decompress(): 1252. functions for easier in-memory compression and
decompression.  Keep in mind that text needs to be encoded as *note
bytes: 1c2. before compressing and decompressing:

     >>> import gzip
     >>> s = 'Three shall be the number thou shalt count, '
     >>> s += 'and the number of the counting shall be three'
     >>> b = s.encode()                        # convert to utf-8
     >>> len(b)
     89
     >>> c = gzip.compress(b)
     >>> len(c)
     77
     >>> gzip.decompress(c).decode()[:42]      # decompress and convert to text
     'Three shall be the number thou shalt count'

(Contributed by Anand B. Pillai in bpo-3488(1); and by Antoine Pitrou,
Nir Aides and Brian Curtin in bpo-9962(2), bpo-1675951(3), bpo-7471(4)
and bpo-2846(5).)

Also, the *note zipfile.ZipExtFile: 41e. class was reworked internally
to represent files stored inside an archive.  The new implementation is
significantly faster and can be wrapped in an *note io.BufferedReader:
1253. object for more speedups.  It also solves an issue where
interleaved calls to 'read' and 'readline' gave the wrong results.

(Patch submitted by Nir Aides in bpo-7610(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3488

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9962

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1675951

   (4) https://bugs.python.org/issue?@action=redirect&bpo=7471

   (5) https://bugs.python.org/issue?@action=redirect&bpo=2846

   (6) https://bugs.python.org/issue?@action=redirect&bpo=7610


File: python.info,  Node: tarfile<10>,  Next: hashlib<7>,  Prev: gzip and zipfile,  Up: New Improved and Deprecated Modules

1.12.9.20 tarfile
.................

The *note TarFile: 1255. class can now be used as a context manager.  In
addition, its *note add(): c14. method has a new option, 'filter', that
controls which files are added to the archive and allows the file
metadata to be edited.

The new 'filter' option replaces the older, less flexible 'exclude'
parameter which is now deprecated.  If specified, the optional 'filter'
parameter needs to be a *note keyword argument: d3a.  The user-supplied
filter function accepts a *note TarInfo: 1256. object and returns an
updated ‘TarInfo’ object, or if it wants the file to be excluded, the
function can return ‘None’:

     >>> import tarfile, glob

     >>> def myfilter(tarinfo):
     ...     if tarinfo.isfile():             # only save real files
     ...         tarinfo.uname = 'monty'      # redact the user name
     ...         return tarinfo

     >>> with tarfile.open(name='myarchive.tar.gz', mode='w:gz') as tf:
     ...     for filename in glob.glob('*.txt'):
     ...         tf.add(filename, filter=myfilter)
     ...     tf.list()
     -rw-r--r-- monty/501        902 2011-01-26 17:59:11 annotations.txt
     -rw-r--r-- monty/501        123 2011-01-26 17:59:11 general_questions.txt
     -rw-r--r-- monty/501       3514 2011-01-26 17:59:11 prion.txt
     -rw-r--r-- monty/501        124 2011-01-26 17:59:11 py_todo.txt
     -rw-r--r-- monty/501       1399 2011-01-26 17:59:11 semaphore_notes.txt

(Proposed by Tarek Ziadé and implemented by Lars Gustäbel in
bpo-6856(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6856


File: python.info,  Node: hashlib<7>,  Next: ast<5>,  Prev: tarfile<10>,  Up: New Improved and Deprecated Modules

1.12.9.21 hashlib
.................

The *note hashlib: 68. module has two new constant attributes listing
the hashing algorithms guaranteed to be present in all implementations
and those available on the current implementation:

     >>> import hashlib

     >>> hashlib.algorithms_guaranteed
     {'sha1', 'sha224', 'sha384', 'sha256', 'sha512', 'md5'}

     >>> hashlib.algorithms_available
     {'md2', 'SHA256', 'SHA512', 'dsaWithSHA', 'mdc2', 'SHA224', 'MD4', 'sha256',
     'sha512', 'ripemd160', 'SHA1', 'MDC2', 'SHA', 'SHA384', 'MD2',
     'ecdsa-with-SHA1','md4', 'md5', 'sha1', 'DSA-SHA', 'sha224',
     'dsaEncryption', 'DSA', 'RIPEMD160', 'sha', 'MD5', 'sha384'}

(Suggested by Carl Chenet in bpo-7418(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7418


File: python.info,  Node: ast<5>,  Next: os<13>,  Prev: hashlib<7>,  Up: New Improved and Deprecated Modules

1.12.9.22 ast
.............

The *note ast: 8. module has a wonderful a general-purpose tool for
safely evaluating expression strings using the Python literal syntax.
The *note ast.literal_eval(): c38. function serves as a secure
alternative to the builtin *note eval(): 180. function which is easily
abused.  Python 3.2 adds *note bytes: 1c2. and *note set: 5dc. literals
to the list of supported types: strings, bytes, numbers, tuples, lists,
dicts, sets, booleans, and ‘None’.

     >>> from ast import literal_eval

     >>> request = "{'req': 3, 'func': 'pow', 'args': (2, 0.5)}"
     >>> literal_eval(request)
     {'args': (2, 0.5), 'req': 3, 'func': 'pow'}

     >>> request = "os.system('do something harmful')"
     >>> literal_eval(request)
     Traceback (most recent call last):
       ...
     ValueError: malformed node or string: <_ast.Call object at 0x101739a10>

(Implemented by Benjamin Peterson and Georg Brandl.)


File: python.info,  Node: os<13>,  Next: shutil<8>,  Prev: ast<5>,  Up: New Improved and Deprecated Modules

1.12.9.23 os
............

Different operating systems use various encodings for filenames and
environment variables.  The *note os: a1. module provides two new
functions, *note fsencode(): c76. and *note fsdecode(): c75, for
encoding and decoding filenames:

     >>> import os
     >>> filename = 'Sehenswürdigkeiten'
     >>> os.fsencode(filename)
     b'Sehensw\xc3\xbcrdigkeiten'

Some operating systems allow direct access to encoded bytes in the
environment.  If so, the *note os.supports_bytes_environ: 125a. constant
will be true.

For direct access to encoded environment variables (if available), use
the new *note os.getenvb(): 125b. function or use *note os.environb:
125c. which is a bytes version of *note os.environ: 11fe.

(Contributed by Victor Stinner.)


File: python.info,  Node: shutil<8>,  Next: sqlite3<11>,  Prev: os<13>,  Up: New Improved and Deprecated Modules

1.12.9.24 shutil
................

The *note shutil.copytree(): a36. function has two new options:

   * 'ignore_dangling_symlinks': when ‘symlinks=False’ so that the
     function copies a file pointed to by a symlink, not the symlink
     itself.  This option will silence the error raised if the file
     doesn’t exist.

   * 'copy_function': is a callable that will be used to copy files.
     *note shutil.copy2(): a69. is used by default.

(Contributed by Tarek Ziadé.)

In addition, the *note shutil: c5. module now supports *note archiving
operations: 125e. for zipfiles, uncompressed tarfiles, gzipped tarfiles,
and bzipped tarfiles.  And there are functions for registering
additional archiving file formats (such as xz compressed tarfiles or
custom formats).

The principal functions are *note make_archive(): 4b6. and *note
unpack_archive(): 46e.  By default, both operate on the current
directory (which can be set by *note os.chdir(): 610.) and on any
sub-directories.  The archive filename needs to be specified with a full
pathname.  The archiving step is non-destructive (the original files are
left unchanged).

     >>> import shutil, pprint

     >>> os.chdir('mydata')  # change to the source directory
     >>> f = shutil.make_archive('/var/backup/mydata',
     ...                         'zip')      # archive the current directory
     >>> f                                   # show the name of archive
     '/var/backup/mydata.zip'
     >>> os.chdir('tmp')                     # change to an unpacking
     >>> shutil.unpack_archive('/var/backup/mydata.zip')  # recover the data

     >>> pprint.pprint(shutil.get_archive_formats())  # display known formats
     [('bztar', "bzip2'ed tar-file"),
      ('gztar', "gzip'ed tar-file"),
      ('tar', 'uncompressed tar file'),
      ('zip', 'ZIP file')]

     >>> shutil.register_archive_format(     # register a new archive format
     ...     name='xz',
     ...     function=xz.compress,           # callable archiving function
     ...     extra_args=[('level', 8)],      # arguments to the function
     ...     description='xz compression'
     ... )

(Contributed by Tarek Ziadé.)


File: python.info,  Node: sqlite3<11>,  Next: html<3>,  Prev: shutil<8>,  Up: New Improved and Deprecated Modules

1.12.9.25 sqlite3
.................

The *note sqlite3: cf. module was updated to pysqlite version 2.6.0.  It
has two new capabilities.

   * The ‘sqlite3.Connection.in_transit’ attribute is true if there is
     an active transaction for uncommitted changes.

   * The *note sqlite3.Connection.enable_load_extension(): 844. and
     *note sqlite3.Connection.load_extension(): 4bb. methods allows you
     to load SQLite extensions from “.so” files.  One well-known
     extension is the fulltext-search extension distributed with SQLite.

(Contributed by R. David Murray and Shashwat Anand; bpo-8845(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8845


File: python.info,  Node: html<3>,  Next: socket<11>,  Prev: sqlite3<11>,  Up: New Improved and Deprecated Modules

1.12.9.26 html
..............

A new *note html: 6b. module was introduced with only a single function,
*note escape(): 1049, which is used for escaping reserved characters
from HTML markup:

     >>> import html
     >>> html.escape('x > 2 && x < 7')
     'x &gt; 2 &amp;&amp; x &lt; 7'


File: python.info,  Node: socket<11>,  Next: ssl<12>,  Prev: html<3>,  Up: New Improved and Deprecated Modules

1.12.9.27 socket
................

The *note socket: cc. module has two new improvements.

   * Socket objects now have a *note detach(): 1262. method which puts
     the socket into closed state without actually closing the
     underlying file descriptor.  The latter can then be reused for
     other purposes.  (Added by Antoine Pitrou; bpo-8524(1).)

   * *note socket.create_connection(): 675. now supports the context
     management protocol to unconditionally consume *note socket.error:
     1093. exceptions and to close the socket when done.  (Contributed
     by Giampaolo Rodolà; bpo-9794(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8524

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9794


File: python.info,  Node: ssl<12>,  Next: nntp,  Prev: socket<11>,  Up: New Improved and Deprecated Modules

1.12.9.28 ssl
.............

The *note ssl: d0. module added a number of features to satisfy common
requirements for secure (encrypted, authenticated) internet connections:

   * A new class, *note SSLContext: 294, serves as a container for
     persistent SSL data, such as protocol settings, certificates,
     private keys, and various other options.  It includes a *note
     wrap_socket(): 528. for creating an SSL socket from an SSL context.

   * A new function, ‘ssl.match_hostname()’, supports server identity
     verification for higher-level protocols by implementing the rules
     of HTTPS (from RFC 2818(1)) which are also suitable for other
     protocols.

   * The *note ssl.wrap_socket(): 528. constructor function now takes a
     'ciphers' argument.  The 'ciphers' string lists the allowed
     encryption algorithms using the format described in the OpenSSL
     documentation(2).

   * When linked against recent versions of OpenSSL, the *note ssl: d0.
     module now supports the Server Name Indication extension to the TLS
     protocol, allowing multiple “virtual hosts” using different
     certificates on a single IP port.  This extension is only supported
     in client mode, and is activated by passing the 'server_hostname'
     argument to *note ssl.SSLContext.wrap_socket(): 528.

   * Various options have been added to the *note ssl: d0. module, such
     as *note OP_NO_SSLv2: 83f. which disables the insecure and obsolete
     SSLv2 protocol.

   * The extension now loads all the OpenSSL ciphers and digest
     algorithms.  If some SSL certificates cannot be verified, they are
     reported as an “unknown algorithm” error.

   * The version of OpenSSL being used is now accessible using the
     module attributes *note ssl.OPENSSL_VERSION: 1264. (a string),
     *note ssl.OPENSSL_VERSION_INFO: 1265. (a 5-tuple), and *note
     ssl.OPENSSL_VERSION_NUMBER: 1266. (an integer).

(Contributed by Antoine Pitrou in bpo-8850(3), bpo-1589(4), bpo-8322(5),
bpo-5639(6), bpo-4870(7), bpo-8484(8), and bpo-8321(9).)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2818.html

   (2) https://docs.openssl.org/1.0.2/man1/ciphers/#cipher-list-format

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8850

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1589

   (5) https://bugs.python.org/issue?@action=redirect&bpo=8322

   (6) https://bugs.python.org/issue?@action=redirect&bpo=5639

   (7) https://bugs.python.org/issue?@action=redirect&bpo=4870

   (8) https://bugs.python.org/issue?@action=redirect&bpo=8484

   (9) https://bugs.python.org/issue?@action=redirect&bpo=8321


File: python.info,  Node: nntp,  Next: certificates,  Prev: ssl<12>,  Up: New Improved and Deprecated Modules

1.12.9.29 nntp
..............

The ‘nntplib’ module has a revamped implementation with better bytes and
text semantics as well as more practical APIs.  These improvements break
compatibility with the nntplib version in Python 3.1, which was partly
dysfunctional in itself.

Support for secure connections through both implicit (using
‘nntplib.NNTP_SSL’) and explicit (using ‘nntplib.NNTP.starttls()’) TLS
has also been added.

(Contributed by Antoine Pitrou in bpo-9360(1) and Andrew Vant in
bpo-1926(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9360

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1926


File: python.info,  Node: certificates,  Next: imaplib<4>,  Prev: nntp,  Up: New Improved and Deprecated Modules

1.12.9.30 certificates
......................

*note http.client.HTTPSConnection: b5a, *note
urllib.request.HTTPSHandler: 1269. and *note urllib.request.urlopen():
293. now take optional arguments to allow for server certificate
checking against a set of Certificate Authorities, as recommended in
public uses of HTTPS.

(Added by Antoine Pitrou, bpo-9003(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9003


File: python.info,  Node: imaplib<4>,  Next: http client<4>,  Prev: certificates,  Up: New Improved and Deprecated Modules

1.12.9.31 imaplib
.................

Support for explicit TLS on standard IMAP4 connections has been added
through the new *note imaplib.IMAP4.starttls: 126b. method.

(Contributed by Lorenzo M. Catucci and Antoine Pitrou, bpo-4471(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4471


File: python.info,  Node: http client<4>,  Next: unittest<11>,  Prev: imaplib<4>,  Up: New Improved and Deprecated Modules

1.12.9.32 http.client
.....................

There were a number of small API improvements in the *note http.client:
6f. module.  The old-style HTTP 0.9 simple responses are no longer
supported and the 'strict' parameter is deprecated in all classes.

The *note HTTPConnection: b59. and *note HTTPSConnection: b5a. classes
now have a 'source_address' parameter for a (host, port) tuple
indicating where the HTTP connection is made from.

Support for certificate checking and HTTPS virtual hosts were added to
*note HTTPSConnection: b5a.

The *note request(): ccf. method on connection objects allowed an
optional 'body' argument so that a *note file object: 1208. could be
used to supply the content of the request.  Conveniently, the 'body'
argument now also accepts an *note iterable: 126d. object so long as it
includes an explicit ‘Content-Length’ header.  This extended interface
is much more flexible than before.

To establish an HTTPS connection through a proxy server, there is a new
*note set_tunnel(): 126e. method that sets the host and port for HTTP
Connect tunneling.

To match the behavior of *note http.server: 72, the HTTP client library
now also encodes headers with ISO-8859-1 (Latin-1) encoding.  It was
already doing that for incoming headers, so now the behavior is
consistent for both incoming and outgoing traffic.  (See work by Armin
Ronacher in bpo-10980(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10980


File: python.info,  Node: unittest<11>,  Next: random<5>,  Prev: http client<4>,  Up: New Improved and Deprecated Modules

1.12.9.33 unittest
..................

The unittest module has a number of improvements supporting test
discovery for packages, easier experimentation at the interactive
prompt, new testcase methods, improved diagnostic messages for test
failures, and better method names.

   * The command-line call ‘python -m unittest’ can now accept file
     paths instead of module names for running specific tests
     (bpo-10620(1)).  The new test discovery can find tests within
     packages, locating any test importable from the top-level
     directory.  The top-level directory can be specified with the ‘-t’
     option, a pattern for matching files with ‘-p’, and a directory to
     start discovery with ‘-s’:

          $ python -m unittest discover -s my_proj_dir -p _test.py

     (Contributed by Michael Foord.)

   * Experimentation at the interactive prompt is now easier because the
     *note unittest.TestCase: 451. class can now be instantiated without
     arguments:

          >>> from unittest import TestCase
          >>> TestCase().assertEqual(pow(2, 3), 8)

     (Contributed by Michael Foord.)

   * The *note unittest: 106. module has two new methods, *note
     assertWarns(): 11a8. and *note assertWarnsRegex(): 11a9. to verify
     that a given warning type is triggered by the code under test:

          with self.assertWarns(DeprecationWarning):
              legacy_function('XYZ')

     (Contributed by Antoine Pitrou, bpo-9754(2).)

     Another new method, *note assertCountEqual(): 1270. is used to
     compare two iterables to determine if their element counts are
     equal (whether the same elements are present with the same number
     of occurrences regardless of order):

          def test_anagram(self):
              self.assertCountEqual('algorithm', 'logarithm')

     (Contributed by Raymond Hettinger.)

   * A principal feature of the unittest module is an effort to produce
     meaningful diagnostics when a test fails.  When possible, the
     failure is recorded along with a diff of the output.  This is
     especially helpful for analyzing log files of failed test runs.
     However, since diffs can sometime be voluminous, there is a new
     *note maxDiff: 1271. attribute that sets maximum length of diffs
     displayed.

   * In addition, the method names in the module have undergone a number
     of clean-ups.

     For example, *note assertRegex(): 531. is the new name for
     ‘assertRegexpMatches()’ which was misnamed because the test uses
     *note re.search(): 1272, not *note re.match(): 1273.  Other methods
     using regular expressions are now named using short form “Regex” in
     preference to “Regexp” – this matches the names used in other
     unittest implementations, matches Python’s old name for the *note
     re: b9. module, and it has unambiguous camel-casing.

     (Contributed by Raymond Hettinger and implemented by Ezio Melotti.)

   * To improve consistency, some long-standing method aliases are being
     deprecated in favor of the preferred names:

          Old Name                            Preferred Name
                                              
          -----------------------------------------------------------------------
                                              
          ‘assert_()’                         *note assertTrue(): 52a.
                                              
                                              
          ‘assertEquals()’                    *note assertEqual(): 52c.
                                              
                                              
          ‘assertNotEquals()’                 *note assertNotEqual(): 52d.
                                              
                                              
          ‘assertAlmostEquals()’              *note assertAlmostEqual(): 52e.
                                              
                                              
          ‘assertNotAlmostEquals()’           *note assertNotAlmostEqual(): 52f.
                                              

     Likewise, the ‘TestCase.fail*’ methods deprecated in Python 3.1 are
     expected to be removed in Python 3.3.

     (Contributed by Ezio Melotti; bpo-9424(3).)

   * The ‘assertDictContainsSubset()’ method was deprecated because it
     was misimplemented with the arguments in the wrong order.  This
     created hard-to-debug optical illusions where tests like
     ‘TestCase().assertDictContainsSubset({'a':1, 'b':2}, {'a':1})’
     would fail.

     (Contributed by Raymond Hettinger.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10620

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9754

   (3) https://bugs.python.org/issue?@action=redirect&bpo=9424


File: python.info,  Node: random<5>,  Next: poplib<4>,  Prev: unittest<11>,  Up: New Improved and Deprecated Modules

1.12.9.34 random
................

The integer methods in the *note random: b8. module now do a better job
of producing uniform distributions.  Previously, they computed
selections with ‘int(n*random())’ which had a slight bias whenever 'n'
was not a power of two.  Now, multiple selections are made from a range
up to the next power of two and a selection is kept only when it falls
within the range ‘0 <= x < n’.  The functions and methods affected are
*note randrange(): 872, *note randint(): 1275, *note choice(): 1276,
*note shuffle(): 74a. and *note sample(): 749.

(Contributed by Raymond Hettinger; bpo-9025(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9025


File: python.info,  Node: poplib<4>,  Next: asyncore<2>,  Prev: random<5>,  Up: New Improved and Deprecated Modules

1.12.9.35 poplib
................

*note POP3_SSL: 92e. class now accepts a 'context' parameter, which is a
*note ssl.SSLContext: 294. object allowing bundling SSL configuration
options, certificates and private keys into a single (potentially
long-lived) structure.

(Contributed by Giampaolo Rodolà; bpo-8807(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8807


File: python.info,  Node: asyncore<2>,  Next: tempfile<5>,  Prev: poplib<4>,  Up: New Improved and Deprecated Modules

1.12.9.36 asyncore
..................

‘asyncore.dispatcher’ now provides a ‘handle_accepted()’ method
returning a ‘(sock, addr)’ pair which is called when a connection has
actually been established with a new remote endpoint.  This is supposed
to be used as a replacement for old ‘handle_accept()’ and avoids the
user to call ‘accept()’ directly.

(Contributed by Giampaolo Rodolà; bpo-6706(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6706


File: python.info,  Node: tempfile<5>,  Next: inspect<10>,  Prev: asyncore<2>,  Up: New Improved and Deprecated Modules

1.12.9.37 tempfile
..................

The *note tempfile: e0. module has a new context manager, *note
TemporaryDirectory: 127a. which provides easy deterministic cleanup of
temporary directories:

     with tempfile.TemporaryDirectory() as tmpdirname:
         print('created temporary dir:', tmpdirname)

(Contributed by Neil Schemenauer and Nick Coghlan; bpo-5178(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5178


File: python.info,  Node: inspect<10>,  Next: pydoc<6>,  Prev: tempfile<5>,  Up: New Improved and Deprecated Modules

1.12.9.38 inspect
.................

   * The *note inspect: 7e. module has a new function *note
     getgeneratorstate(): 127c. to easily identify the current state of
     a generator-iterator:

          >>> from inspect import getgeneratorstate
          >>> def gen():
          ...     yield 'demo'
          ...
          >>> g = gen()
          >>> getgeneratorstate(g)
          'GEN_CREATED'
          >>> next(g)
          'demo'
          >>> getgeneratorstate(g)
          'GEN_SUSPENDED'
          >>> next(g, None)
          >>> getgeneratorstate(g)
          'GEN_CLOSED'

     (Contributed by Rodolpho Eckhardt and Nick Coghlan, bpo-10220(1).)

   * To support lookups without the possibility of activating a dynamic
     attribute, the *note inspect: 7e. module has a new function, *note
     getattr_static(): 497.  Unlike *note hasattr(): 4d5, this is a true
     read-only search, guaranteed not to change state while it is
     searching:

          >>> class A:
          ...     @property
          ...     def f(self):
          ...         print('Running')
          ...         return 10
          ...
          >>> a = A()
          >>> getattr(a, 'f')
          Running
          10
          >>> inspect.getattr_static(a, 'f')
          <property object at 0x1022bd788>

     (Contributed by Michael Foord.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10220


File: python.info,  Node: pydoc<6>,  Next: dis<5>,  Prev: inspect<10>,  Up: New Improved and Deprecated Modules

1.12.9.39 pydoc
...............

The *note pydoc: b5. module now provides a much-improved web server
interface, as well as a new command-line option ‘-b’ to automatically
open a browser window to display that server:

     $ pydoc3.2 -b

(Contributed by Ron Adam; bpo-2001(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2001


File: python.info,  Node: dis<5>,  Next: dbm<7>,  Prev: pydoc<6>,  Up: New Improved and Deprecated Modules

1.12.9.40 dis
.............

The *note dis: 38. module gained two new functions for inspecting code,
*note code_info(): 127f. and *note show_code(): f63.  Both provide
detailed code object information for the supplied function, method,
source code string or code object.  The former returns a string and the
latter prints it:

     >>> import dis, random
     >>> dis.show_code(random.choice)
     Name:              choice
     Filename:          /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/random.py
     Argument count:    2
     Kw-only arguments: 0
     Number of locals:  3
     Stack size:        11
     Flags:             OPTIMIZED, NEWLOCALS, NOFREE
     Constants:
        0: 'Choose a random element from a non-empty sequence.'
        1: 'Cannot choose from an empty sequence'
     Names:
        0: _randbelow
        1: len
        2: ValueError
        3: IndexError
     Variable names:
        0: self
        1: seq
        2: i

In addition, the *note dis(): b4c. function now accepts string arguments
so that the common idiom ‘dis(compile(s, '', 'eval'))’ can be shortened
to ‘dis(s)’:

     >>> dis('3*x+1 if x%2==1 else x//2')
       1           0 LOAD_NAME                0 (x)
                   3 LOAD_CONST               0 (2)
                   6 BINARY_MODULO
                   7 LOAD_CONST               1 (1)
                  10 COMPARE_OP               2 (==)
                  13 POP_JUMP_IF_FALSE       28
                  16 LOAD_CONST               2 (3)
                  19 LOAD_NAME                0 (x)
                  22 BINARY_MULTIPLY
                  23 LOAD_CONST               1 (1)
                  26 BINARY_ADD
                  27 RETURN_VALUE
             >>   28 LOAD_NAME                0 (x)
                  31 LOAD_CONST               0 (2)
                  34 BINARY_FLOOR_DIVIDE
                  35 RETURN_VALUE

Taken together, these improvements make it easier to explore how CPython
is implemented and to see for yourself what the language syntax does
under-the-hood.

(Contributed by Nick Coghlan in bpo-9147(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9147


File: python.info,  Node: dbm<7>,  Next: ctypes<3>,  Prev: dis<5>,  Up: New Improved and Deprecated Modules

1.12.9.41 dbm
.............

All database modules now support the ‘get()’ and ‘setdefault()’ methods.

(Suggested by Ray Allen in bpo-9523(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9523


File: python.info,  Node: ctypes<3>,  Next: site<4>,  Prev: dbm<7>,  Up: New Improved and Deprecated Modules

1.12.9.42 ctypes
................

A new type, *note ctypes.c_ssize_t: 1282. represents the C ‘ssize_t’
datatype.


File: python.info,  Node: site<4>,  Next: sysconfig<3>,  Prev: ctypes<3>,  Up: New Improved and Deprecated Modules

1.12.9.43 site
..............

The *note site: c7. module has three new functions useful for reporting
on the details of a given Python installation.

   * *note getsitepackages(): 1284. lists all global site-packages
     directories.

   * *note getuserbase(): 1285. reports on the user’s base directory
     where data can be stored.

   * *note getusersitepackages(): 1286. reveals the user-specific
     site-packages directory path.

     >>> import site
     >>> site.getsitepackages()
     ['/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages',
      '/Library/Frameworks/Python.framework/Versions/3.2/lib/site-python',
      '/Library/Python/3.2/site-packages']
     >>> site.getuserbase()
     '/Users/raymondhettinger/Library/Python/3.2'
     >>> site.getusersitepackages()
     '/Users/raymondhettinger/Library/Python/3.2/lib/python/site-packages'

Conveniently, some of site’s functionality is accessible directly from
the command-line:

     $ python -m site --user-base
     /Users/raymondhettinger/.local
     $ python -m site --user-site
     /Users/raymondhettinger/.local/lib/python3.2/site-packages

(Contributed by Tarek Ziadé in bpo-6693(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6693


File: python.info,  Node: sysconfig<3>,  Next: pdb<8>,  Prev: site<4>,  Up: New Improved and Deprecated Modules

1.12.9.44 sysconfig
...................

The new *note sysconfig: db. module makes it straightforward to discover
installation paths and configuration variables that vary across
platforms and installations.

The module offers access simple access functions for platform and
version information:

   * *note get_platform(): 1288. returning values like 'linux-i586' or
     'macosx-10.6-ppc'.

   * *note get_python_version(): 1289. returns a Python version string
     such as “3.2”.

It also provides access to the paths and variables corresponding to one
of seven named schemes used by ‘distutils’.  Those include
'posix_prefix', 'posix_home', 'posix_user', 'nt', 'nt_user', 'os2',
'os2_home':

   * *note get_paths(): 128a. makes a dictionary containing installation
     paths for the current installation scheme.

   * *note get_config_vars(): 1069. returns a dictionary of platform
     specific variables.

There is also a convenient command-line interface:

     C:\Python32>python -m sysconfig
     Platform: "win32"
     Python version: "3.2"
     Current installation scheme: "nt"

     Paths:
             data = "C:\Python32"
             include = "C:\Python32\Include"
             platinclude = "C:\Python32\Include"
             platlib = "C:\Python32\Lib\site-packages"
             platstdlib = "C:\Python32\Lib"
             purelib = "C:\Python32\Lib\site-packages"
             scripts = "C:\Python32\Scripts"
             stdlib = "C:\Python32\Lib"

     Variables:
             BINDIR = "C:\Python32"
             BINLIBDEST = "C:\Python32\Lib"
             EXE = ".exe"
             INCLUDEPY = "C:\Python32\Include"
             LIBDEST = "C:\Python32\Lib"
             SO = ".pyd"
             VERSION = "32"
             abiflags = ""
             base = "C:\Python32"
             exec_prefix = "C:\Python32"
             platbase = "C:\Python32"
             prefix = "C:\Python32"
             projectbase = "C:\Python32"
             py_version = "3.2"
             py_version_nodot = "32"
             py_version_short = "3.2"
             srcdir = "C:\Python32"
             userbase = "C:\Documents and Settings\Raymond\Application Data\Python"

(Moved out of Distutils by Tarek Ziadé.)


File: python.info,  Node: pdb<8>,  Next: configparser<5>,  Prev: sysconfig<3>,  Up: New Improved and Deprecated Modules

1.12.9.45 pdb
.............

The *note pdb: a5. debugger module gained a number of usability
improvements:

   * ‘pdb.py’ now has a ‘-c’ option that executes commands as given in a
     ‘.pdbrc’ script file.

   * A ‘.pdbrc’ script file can contain ‘continue’ and ‘next’ commands
     that continue debugging.

   * The *note Pdb: 92b. class constructor now accepts a 'nosigint'
     argument.

   * New commands: ‘l(list)’, ‘ll(long list)’ and ‘source’ for listing
     source code.

   * New commands: ‘display’ and ‘undisplay’ for showing or hiding the
     value of an expression if it has changed.

   * New command: ‘interact’ for starting an interactive interpreter
     containing the global and local names found in the current scope.

   * Breakpoints can be cleared by breakpoint number.

(Contributed by Georg Brandl, Antonio Cuni and Ilya Sandler.)


File: python.info,  Node: configparser<5>,  Next: urllib parse<6>,  Prev: pdb<8>,  Up: New Improved and Deprecated Modules

1.12.9.46 configparser
......................

The *note configparser: 22. module was modified to improve usability and
predictability of the default parser and its supported INI syntax.  The
old ‘ConfigParser’ class was removed in favor of ‘SafeConfigParser’
which has in turn been renamed to *note ConfigParser: 1c8.  Support for
inline comments is now turned off by default and section or option
duplicates are not allowed in a single configuration source.

Config parsers gained a new API based on the mapping protocol:

     >>> parser = ConfigParser()
     >>> parser.read_string("""
     ... [DEFAULT]
     ... location = upper left
     ... visible = yes
     ... editable = no
     ... color = blue
     ...
     ... [main]
     ... title = Main Menu
     ... color = green
     ...
     ... [options]
     ... title = Options
     ... """)
     >>> parser['main']['color']
     'green'
     >>> parser['main']['editable']
     'no'
     >>> section = parser['options']
     >>> section['title']
     'Options'
     >>> section['title'] = 'Options (editable: %(editable)s)'
     >>> section['title']
     'Options (editable: no)'

The new API is implemented on top of the classical API, so custom parser
subclasses should be able to use it without modifications.

The INI file structure accepted by config parsers can now be customized.
Users can specify alternative option/value delimiters and comment
prefixes, change the name of the 'DEFAULT' section or switch the
interpolation syntax.

There is support for pluggable interpolation including an additional
interpolation handler *note ExtendedInterpolation: 726.:

     >>> parser = ConfigParser(interpolation=ExtendedInterpolation())
     >>> parser.read_dict({'buildout': {'directory': '/home/ambv/zope9'},
     ...                   'custom': {'prefix': '/usr/local'}})
     >>> parser.read_string("""
     ... [buildout]
     ... parts =
     ...   zope9
     ...   instance
     ... find-links =
     ...   ${buildout:directory}/downloads/dist
     ...
     ... [zope9]
     ... recipe = plone.recipe.zope9install
     ... location = /opt/zope
     ...
     ... [instance]
     ... recipe = plone.recipe.zope9instance
     ... zope9-location = ${zope9:location}
     ... zope-conf = ${custom:prefix}/etc/zope.conf
     ... """)
     >>> parser['buildout']['find-links']
     '\n/home/ambv/zope9/downloads/dist'
     >>> parser['instance']['zope-conf']
     '/usr/local/etc/zope.conf'
     >>> instance = parser['instance']
     >>> instance['zope-conf']
     '/usr/local/etc/zope.conf'
     >>> instance['zope9-location']
     '/opt/zope'

A number of smaller features were also introduced, like support for
specifying encoding in read operations, specifying fallback values for
get-functions, or reading directly from dictionaries and strings.

(All changes contributed by Łukasz Langa.)


File: python.info,  Node: urllib parse<6>,  Next: mailbox,  Prev: configparser<5>,  Up: New Improved and Deprecated Modules

1.12.9.47 urllib.parse
......................

A number of usability improvements were made for the *note urllib.parse:
10a. module.

The *note urlparse(): 30d. function now supports IPv6(1) addresses as
described in RFC 2732(2):

     >>> import urllib.parse
     >>> urllib.parse.urlparse('http://[dead:beef:cafe:5417:affe:8FA3:deaf:feed]/foo/')
     ParseResult(scheme='http',
                 netloc='[dead:beef:cafe:5417:affe:8FA3:deaf:feed]',
                 path='/foo/',
                 params='',
                 query='',
                 fragment='')

The *note urldefrag(): 128e. function now returns a *note named tuple:
651.:

     >>> r = urllib.parse.urldefrag('http://python.org/about/#target')
     >>> r
     DefragResult(url='http://python.org/about/', fragment='target')
     >>> r[0]
     'http://python.org/about/'
     >>> r.fragment
     'target'

And, the *note urlencode(): ec9. function is now much more flexible,
accepting either a string or bytes type for the 'query' argument.  If it
is a string, then the 'safe', 'encoding', and 'error' parameters are
sent to *note quote_plus(): 128f. for encoding:

     >>> urllib.parse.urlencode([
     ...      ('type', 'telenovela'),
     ...      ('name', '¿Dónde Está Elisa?')],
     ...      encoding='latin-1')
     'type=telenovela&name=%BFD%F3nde+Est%E1+Elisa%3F'

As detailed in *note Parsing ASCII Encoded Bytes: 1290, all the *note
urllib.parse: 10a. functions now accept ASCII-encoded byte strings as
input, so long as they are not mixed with regular strings.  If
ASCII-encoded byte strings are given as parameters, the return types
will also be an ASCII-encoded byte strings:

     >>> urllib.parse.urlparse(b'http://www.python.org:80/about/')
     ParseResultBytes(scheme=b'http', netloc=b'www.python.org:80',
                      path=b'/about/', params=b'', query=b'', fragment=b'')

(Work by Nick Coghlan, Dan Mahn, and Senthil Kumaran in bpo-2987(3),
bpo-5468(4), and bpo-9873(5).)

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/IPv6

   (2) https://datatracker.ietf.org/doc/html/rfc2732.html

   (3) https://bugs.python.org/issue?@action=redirect&bpo=2987

   (4) https://bugs.python.org/issue?@action=redirect&bpo=5468

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9873


File: python.info,  Node: mailbox,  Next: turtledemo,  Prev: urllib parse<6>,  Up: New Improved and Deprecated Modules

1.12.9.48 mailbox
.................

Thanks to a concerted effort by R. David Murray, the *note mailbox: 8b.
module has been fixed for Python 3.2.  The challenge was that mailbox
had been originally designed with a text interface, but email messages
are best represented with *note bytes: 1c2. because various parts of a
message may have different encodings.

The solution harnessed the *note email: 3b. package’s binary support for
parsing arbitrary email messages.  In addition, the solution required a
number of API changes.

As expected, the *note add(): 1292. method for *note mailbox.Mailbox:
1293. objects now accepts binary input.

*note StringIO: f5e. and text file input are deprecated.  Also, string
input will fail early if non-ASCII characters are used.  Previously it
would fail when the email was processed in a later step.

There is also support for binary output.  The *note get_file(): 1294.
method now returns a file in the binary mode (where it used to
incorrectly set the file to text-mode).  There is also a new *note
get_bytes(): 1295. method that returns a *note bytes: 1c2.
representation of a message corresponding to a given 'key'.

It is still possible to get non-binary output using the old API’s *note
get_string(): 1296. method, but that approach is not very useful.
Instead, it is best to extract messages from a *note Message: 1297.
object or to load them from binary input.

(Contributed by R. David Murray, with efforts from Steffen Daode
Nurpmeso and an initial patch by Victor Stinner in bpo-9124(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=9124


File: python.info,  Node: turtledemo,  Prev: mailbox,  Up: New Improved and Deprecated Modules

1.12.9.49 turtledemo
....................

The demonstration code for the *note turtle: 101. module was moved from
the 'Demo' directory to main library.  It includes over a dozen sample
scripts with lively displays.  Being on *note sys.path: 3b7, it can now
be run directly from the command-line:

     $ python -m turtledemo

(Moved from the Demo directory by Alexander Belopolsky in bpo-10199(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10199


File: python.info,  Node: Multi-threading,  Next: Optimizations<11>,  Prev: New Improved and Deprecated Modules,  Up: What’s New In Python 3 2

1.12.10 Multi-threading
-----------------------

   * The mechanism for serializing execution of concurrently running
     Python threads (generally known as the *note GIL: 159. or Global
     Interpreter Lock) has been rewritten.  Among the objectives were
     more predictable switching intervals and reduced overhead due to
     lock contention and the number of ensuing system calls.  The notion
     of a “check interval” to allow thread switches has been abandoned
     and replaced by an absolute duration expressed in seconds.  This
     parameter is tunable through *note sys.setswitchinterval(): 954.
     It currently defaults to 5 milliseconds.

     Additional details about the implementation can be read from a
     python-dev mailing-list message(1) (however, “priority requests” as
     exposed in this message have not been kept for inclusion).

     (Contributed by Antoine Pitrou.)

   * Regular and recursive locks now accept an optional 'timeout'
     argument to their *note acquire(): 69b. method.  (Contributed by
     Antoine Pitrou; bpo-7316(2).)

   * Similarly, *note threading.Semaphore.acquire(): 129a. also gained a
     'timeout' argument.  (Contributed by Torsten Landschoff;
     bpo-850728(3).)

   * Regular and recursive lock acquisitions can now be interrupted by
     signals on platforms using Pthreads.  This means that Python
     programs that deadlock while acquiring locks can be successfully
     killed by repeatedly sending SIGINT to the process (by pressing
     ‘Ctrl’+‘C’ in most shells).  (Contributed by Reid Kleckner;
     bpo-8844(4).)

   ---------- Footnotes ----------

   (1) 
https://mail.python.org/pipermail/python-dev/2009-October/093321.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=7316

   (3) https://bugs.python.org/issue?@action=redirect&bpo=850728

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8844


File: python.info,  Node: Optimizations<11>,  Next: Unicode,  Prev: Multi-threading,  Up: What’s New In Python 3 2

1.12.11 Optimizations
---------------------

A number of small performance enhancements have been added:

   * Python’s peephole optimizer now recognizes patterns such ‘x in {1,
     2, 3}’ as being a test for membership in a set of constants.  The
     optimizer recasts the *note set: 5dc. as a *note frozenset: 5dd.
     and stores the pre-built constant.

     Now that the speed penalty is gone, it is practical to start
     writing membership tests using set-notation.  This style is both
     semantically clear and operationally fast:

          extension = name.rpartition('.')[2]
          if extension in {'xml', 'html', 'xhtml', 'css'}:
              handle(name)

     (Patch and additional tests contributed by Dave Malcolm;
     bpo-6690(1)).

   * Serializing and unserializing data using the *note pickle: a6.
     module is now several times faster.

     (Contributed by Alexandre Vassalotti, Antoine Pitrou and the
     Unladen Swallow team in bpo-9410(2) and bpo-3873(3).)

   * The Timsort algorithm(4) used in *note list.sort(): bee. and *note
     sorted(): bed. now runs faster and uses less memory when called
     with a *note key function: e37.  Previously, every element of a
     list was wrapped with a temporary object that remembered the key
     value associated with each element.  Now, two arrays of keys and
     values are sorted in parallel.  This saves the memory consumed by
     the sort wrappers, and it saves time lost to delegating
     comparisons.

     (Patch by Daniel Stutzbach in bpo-9915(5).)

   * JSON decoding performance is improved and memory consumption is
     reduced whenever the same string is repeated for multiple keys.
     Also, JSON encoding now uses the C speedups when the ‘sort_keys’
     argument is true.

     (Contributed by Antoine Pitrou in bpo-7451(6) and by Raymond
     Hettinger and Antoine Pitrou in bpo-10314(7).)

   * Recursive locks (created with the *note threading.RLock(): 2de.
     API) now benefit from a C implementation which makes them as fast
     as regular locks, and between 10x and 15x faster than their
     previous pure Python implementation.

     (Contributed by Antoine Pitrou; bpo-3001(8).)

   * The fast-search algorithm in stringlib is now used by the *note
     split(): ede, *note rsplit(): 129c, *note splitlines(): 129d. and
     *note replace(): 19a. methods on *note bytes: 1c2, *note bytearray:
     2ea. and *note str: 44f. objects.  Likewise, the algorithm is also
     used by *note rfind(): edd, *note rindex(): 129e, ‘rsplit()’ and
     *note rpartition(): 129f.

     (Patch by Florent Xicluna in bpo-7622(9) and bpo-7462(10).)

   * Integer to string conversions now work two “digits” at a time,
     reducing the number of division and modulo operations.

     (bpo-6713(11) by Gawain Bolton, Mark Dickinson, and Victor
     Stinner.)

There were several other minor optimizations.  Set differencing now runs
faster when one operand is much larger than the other (patch by Andress
Bennetts in bpo-8685(12)).  The ‘array.repeat()’ method has a faster
implementation (bpo-1569291(13) by Alexander Belopolsky).  The *note
BaseHTTPRequestHandler: 110f. has more efficient buffering (bpo-3709(14)
by Andrew Schaaf).  The *note operator.attrgetter(): e66. function has
been sped-up (bpo-10160(15) by Christos Georgiou).  And *note
ConfigParser: 1c8. loads multi-line arguments a bit faster (bpo-7113(16)
by Łukasz Langa).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6690

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9410

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3873

   (4) https://en.wikipedia.org/wiki/Timsort

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9915

   (6) https://bugs.python.org/issue?@action=redirect&bpo=7451

   (7) https://bugs.python.org/issue?@action=redirect&bpo=10314

   (8) https://bugs.python.org/issue?@action=redirect&bpo=3001

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7622

   (10) https://bugs.python.org/issue?@action=redirect&bpo=7462

   (11) https://bugs.python.org/issue?@action=redirect&bpo=6713

   (12) https://bugs.python.org/issue?@action=redirect&bpo=8685

   (13) https://bugs.python.org/issue?@action=redirect&bpo=1569291

   (14) https://bugs.python.org/issue?@action=redirect&bpo=3709

   (15) https://bugs.python.org/issue?@action=redirect&bpo=10160

   (16) https://bugs.python.org/issue?@action=redirect&bpo=7113


File: python.info,  Node: Unicode,  Next: Codecs,  Prev: Optimizations<11>,  Up: What’s New In Python 3 2

1.12.12 Unicode
---------------

Python has been updated to Unicode 6.0.0(1).  The update to the standard
adds over 2,000 new characters including emoji(2) symbols which are
important for mobile phones.

In addition, the updated standard has altered the character properties
for two Kannada characters (U+0CF1, U+0CF2) and one New Tai Lue numeric
character (U+19DA), making the former eligible for use in identifiers
while disqualifying the latter.  For more information, see Unicode
Character Database Changes(3).

   ---------- Footnotes ----------

   (1) https://unicode.org/versions/Unicode6.0.0/

   (2) https://en.wikipedia.org/wiki/Emoji

   (3) https://www.unicode.org/versions/Unicode6.0.0/#Database_Changes


File: python.info,  Node: Codecs,  Next: Documentation,  Prev: Unicode,  Up: What’s New In Python 3 2

1.12.13 Codecs
--------------

Support was added for 'cp720' Arabic DOS encoding (bpo-1616979(1)).

MBCS encoding no longer ignores the error handler argument.  In the
default strict mode, it raises an *note UnicodeDecodeError: a20. when it
encounters an undecodable byte sequence and an *note UnicodeEncodeError:
67a. for an unencodable character.

The MBCS codec supports ‘'strict'’ and ‘'ignore'’ error handlers for
decoding, and ‘'strict'’ and ‘'replace'’ for encoding.

To emulate Python3.1 MBCS encoding, select the ‘'ignore'’ handler for
decoding and the ‘'replace'’ handler for encoding.

On Mac OS X, Python decodes command line arguments with ‘'utf-8'’ rather
than the locale encoding.

By default, *note tarfile: de. uses ‘'utf-8'’ encoding on Windows
(instead of ‘'mbcs'’) and the ‘'surrogateescape'’ error handler on all
operating systems.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1616979


File: python.info,  Node: Documentation,  Next: IDLE,  Prev: Codecs,  Up: What’s New In Python 3 2

1.12.14 Documentation
---------------------

The documentation continues to be improved.

   * A table of quick links has been added to the top of lengthy
     sections such as *note Built-in Functions: 12a3.  In the case of
     *note itertools: 81, the links are accompanied by tables of
     cheatsheet-style summaries to provide an overview and memory jog
     without having to read all of the docs.

   * In some cases, the pure Python source code can be a helpful adjunct
     to the documentation, so now many modules now feature quick links
     to the latest version of the source code.  For example, the *note
     functools: 5f. module documentation has a quick link at the top
     labeled:

          'Source code' Lib/functools.py(1).

     (Contributed by Raymond Hettinger; see rationale(2).)

   * The docs now contain more examples and recipes.  In particular,
     *note re: b9. module has an extensive section, *note Regular
     Expression Examples: 12a4.  Likewise, the *note itertools: 81.
     module continues to be updated with new *note Itertools Recipes:
     12a5.

   * The *note datetime: 30. module now has an auxiliary implementation
     in pure Python.  No functionality was changed.  This just provides
     an easier-to-read alternate implementation.

     (Contributed by Alexander Belopolsky in bpo-9528(3).)

   * The unmaintained ‘Demo’ directory has been removed.  Some demos
     were integrated into the documentation, some were moved to the
     ‘Tools/demo’ directory, and others were removed altogether.

     (Contributed by Georg Brandl in bpo-7962(4).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/functools.py

   (2) 
https://rhettinger.wordpress.com/2011/01/28/open-your-source-more/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=9528

   (4) https://bugs.python.org/issue?@action=redirect&bpo=7962


File: python.info,  Node: IDLE,  Next: Code Repository,  Prev: Documentation,  Up: What’s New In Python 3 2

1.12.15 IDLE
------------

   * The format menu now has an option to clean source files by
     stripping trailing whitespace.

     (Contributed by Raymond Hettinger; bpo-5150(1).)

   * IDLE on Mac OS X now works with both Carbon AquaTk and Cocoa
     AquaTk.

     (Contributed by Kevin Walzer, Ned Deily, and Ronald Oussoren;
     bpo-6075(2).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5150

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6075


File: python.info,  Node: Code Repository,  Next: Build and C API Changes<5>,  Prev: IDLE,  Up: What’s New In Python 3 2

1.12.16 Code Repository
-----------------------

In addition to the existing Subversion code repository at
‘https://svn.python.org’ there is now a Mercurial(1) repository at
‘https://hg.python.org/’.

After the 3.2 release, there are plans to switch to Mercurial as the
primary repository.  This distributed version control system should make
it easier for members of the community to create and share external
changesets.  See PEP 385(2) for details.

To learn to use the new version control system, see the Quick Start(3)
or the Guide to Mercurial Workflows(4).

   ---------- Footnotes ----------

   (1) https://www.mercurial-scm.org/

   (2) https://peps.python.org/pep-0385/

   (3) https://www.mercurial-scm.org/wiki/QuickStart

   (4) https://www.mercurial-scm.org/guide


File: python.info,  Node: Build and C API Changes<5>,  Next: Porting to Python 3 2,  Prev: Code Repository,  Up: What’s New In Python 3 2

1.12.17 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * The 'idle', 'pydoc' and '2to3' scripts are now installed with a
     version-specific suffix on ‘make altinstall’ (bpo-10679(1)).

   * The C functions that access the Unicode Database now accept and
     return characters from the full Unicode range, even on narrow
     unicode builds (Py_UNICODE_TOLOWER, Py_UNICODE_ISDECIMAL, and
     others).  A visible difference in Python is that *note
     unicodedata.numeric(): 12a9. now returns the correct value for
     large code points, and *note repr(): 803. may consider more
     characters as printable.

     (Reported by Bupjoe Lee and fixed by Amaury Forgeot D’Arc;
     bpo-5127(2).)

   * Computed gotos are now enabled by default on supported compilers
     (which are detected by the configure script).  They can still be
     disabled selectively by specifying ‘--without-computed-gotos’.

     (Contributed by Antoine Pitrou; bpo-9203(3).)

   * The option ‘--with-wctype-functions’ was removed.  The built-in
     unicode database is now used for all functions.

     (Contributed by Amaury Forgeot D’Arc; bpo-9210(4).)

   * Hash values are now values of a new type, *note Py_hash_t: 12aa,
     which is defined to be the same size as a pointer.  Previously they
     were of type long, which on some 64-bit operating systems is still
     only 32 bits long.  As a result of this fix, *note set: 5dc. and
     *note dict: 256. can now hold more than ‘2**32’ entries on builds
     with 64-bit pointers (previously, they could grow to that size but
     their performance degraded catastrophically).

     (Suggested by Raymond Hettinger and implemented by Benjamin
     Peterson; bpo-9778(5).)

   * A new macro ‘Py_VA_COPY’ copies the state of the variable argument
     list.  It is equivalent to C99 'va_copy' but available on all
     Python platforms (bpo-2443(6)).

   * A new C API function ‘PySys_SetArgvEx()’ allows an embedded
     interpreter to set *note sys.argv: 12ab. without also modifying
     *note sys.path: 3b7. (bpo-5753(7)).

   * ‘PyEval_CallObject()’ is now only available in macro form.  The
     function declaration, which was kept for backwards compatibility
     reasons, is now removed – the macro was introduced in 1997
     (bpo-8276(8)).

   * There is a new function *note PyLong_AsLongLongAndOverflow(): 12ac.
     which is analogous to *note PyLong_AsLongAndOverflow(): 12ad.  They
     both serve to convert Python *note int: 257. into a native
     fixed-width type while providing detection of cases where the
     conversion won’t fit (bpo-7767(9)).

   * The *note PyUnicode_CompareWithASCIIString(): 12ae. function now
     returns 'not equal' if the Python string is 'NUL' terminated.

   * There is a new function *note PyErr_NewExceptionWithDoc(): 12af.
     that is like *note PyErr_NewException(): 12b0. but allows a
     docstring to be specified.  This lets C exceptions have the same
     self-documenting capabilities as their pure Python counterparts
     (bpo-7033(10)).

   * When compiled with the ‘--with-valgrind’ option, the pymalloc
     allocator will be automatically disabled when running under
     Valgrind.  This gives improved memory leak detection when running
     under Valgrind, while taking advantage of pymalloc at other times
     (bpo-2422(11)).

   * Removed the ‘O?’ format from the 'PyArg_Parse' functions.  The
     format is no longer used and it had never been documented
     (bpo-8837(12)).

There were a number of other small changes to the C-API. See the
Misc/NEWS(13) file for a complete list.

Also, there were a number of updates to the Mac OS X build, see
Mac/BuildScript/README.txt(14) for details.  For users running a
32/64-bit build, there is a known problem with the default Tcl/Tk on Mac
OS X 10.6.  Accordingly, we recommend installing an updated alternative
such as ActiveState Tcl/Tk 8.5.9(15).  See
‘https://www.python.org/download/mac/tcltk/’ for additional details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10679

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5127

   (3) https://bugs.python.org/issue?@action=redirect&bpo=9203

   (4) https://bugs.python.org/issue?@action=redirect&bpo=9210

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9778

   (6) https://bugs.python.org/issue?@action=redirect&bpo=2443

   (7) https://bugs.python.org/issue?@action=redirect&bpo=5753

   (8) https://bugs.python.org/issue?@action=redirect&bpo=8276

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7767

   (10) https://bugs.python.org/issue?@action=redirect&bpo=7033

   (11) https://bugs.python.org/issue?@action=redirect&bpo=2422

   (12) https://bugs.python.org/issue?@action=redirect&bpo=8837

   (13) https://github.com/python/cpython/blob/v3.2.6/Misc/NEWS

   (14) 
https://github.com/python/cpython/blob/v3.2.6/Mac/BuildScript/README.txt

   (15) 
https://web.archive.org/web/20101208191259/https://www.activestate.com/activetcl/downloads


File: python.info,  Node: Porting to Python 3 2,  Prev: Build and C API Changes<5>,  Up: What’s New In Python 3 2

1.12.18 Porting to Python 3.2
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code:

   * The *note configparser: 22. module has a number of clean-ups.  The
     major change is to replace the old ‘ConfigParser’ class with
     long-standing preferred alternative ‘SafeConfigParser’.  In
     addition there are a number of smaller incompatibilities:

        * The interpolation syntax is now validated on *note get():
          12b2. and *note set(): 12b3. operations.  In the default
          interpolation scheme, only two tokens with percent signs are
          valid: ‘%(name)s’ and ‘%%’, the latter being an escaped
          percent sign.

        * The *note set(): 12b3. and *note add_section(): 12b4. methods
          now verify that values are actual strings.  Formerly,
          unsupported types could be introduced unintentionally.

        * Duplicate sections or options from a single source now raise
          either *note DuplicateSectionError: 12b5. or *note
          DuplicateOptionError: 12b6.  Formerly, duplicates would
          silently overwrite a previous entry.

        * Inline comments are now disabled by default so now the ';'
          character can be safely used in values.

        * Comments now can be indented.  Consequently, for ';' or '#' to
          appear at the start of a line in multiline values, it has to
          be interpolated.  This keeps comment prefix characters in
          values from being mistaken as comments.

        * ‘""’ is now a valid value and is no longer automatically
          converted to an empty string.  For empty strings, use ‘"option
          ="’ in a line.

   * The ‘nntplib’ module was reworked extensively, meaning that its
     APIs are often incompatible with the 3.1 APIs.

   * *note bytearray: 2ea. objects can no longer be used as filenames;
     instead, they should be converted to *note bytes: 1c2.

   * The ‘array.tostring()’ and ‘array.fromstring()’ have been renamed
     to *note array.tobytes(): 12b7. and *note array.frombytes(): 12b8.
     for clarity.  The old names have been deprecated.  (See
     bpo-8990(1).)

   * ‘PyArg_Parse*()’ functions:

        * “t#” format has been removed: use “s#” or “s*” instead

        * “w” and “w#” formats has been removed: use “w*” instead

   * The ‘PyCObject’ type, deprecated in 3.1, has been removed.  To wrap
     opaque C pointers in Python objects, the *note PyCapsule: 12b9. API
     should be used instead; the new type has a well-defined interface
     for passing typing safety information and a less complicated
     signature for calling a destructor.

   * The ‘sys.setfilesystemencoding()’ function was removed because it
     had a flawed design.

   * The *note random.seed(): 12ba. function and method now salt string
     seeds with an sha512 hash function.  To access the previous version
     of 'seed' in order to reproduce Python 3.1 sequences, set the
     'version' argument to '1', ‘random.seed(s, version=1)’.

   * The previously deprecated ‘string.maketrans()’ function has been
     removed in favor of the static methods *note bytes.maketrans():
     12bb. and *note bytearray.maketrans(): 12bc.  This change solves
     the confusion around which types were supported by the *note
     string: d3. module.  Now, *note str: 44f, *note bytes: 1c2, and
     *note bytearray: 2ea. each have their own 'maketrans' and
     'translate' methods with intermediate translation tables of the
     appropriate type.

     (Contributed by Georg Brandl; bpo-5675(2).)

   * The previously deprecated ‘contextlib.nested()’ function has been
     removed in favor of a plain *note with: 5d5. statement which can
     accept multiple context managers.  The latter technique is faster
     (because it is built-in), and it does a better job finalizing
     multiple context managers when one of them raises an exception:

          with open('mylog.txt') as infile, open('a.out', 'w') as outfile:
              for line in infile:
                  if '<critical>' in line:
                      outfile.write(line)

     (Contributed by Georg Brandl and Mattias Brändström; appspot issue
     53094(3).)

   * *note struct.pack(): 12bd. now only allows bytes for the ‘s’ string
     pack code.  Formerly, it would accept text arguments and implicitly
     encode them to bytes using UTF-8.  This was problematic because it
     made assumptions about the correct encoding and because a
     variable-length encoding can fail when writing to fixed length
     segment of a structure.

     Code such as ‘struct.pack('<6sHHBBB', 'GIF87a', x, y)’ should be
     rewritten with to use bytes instead of text,
     ‘struct.pack('<6sHHBBB', b'GIF87a', x, y)’.

     (Discovered by David Beazley and fixed by Victor Stinner;
     bpo-10783(4).)

   * The *note xml.etree.ElementTree: 125. class now raises an *note
     xml.etree.ElementTree.ParseError: 12be. when a parse fails.
     Previously it raised an *note xml.parsers.expat.ExpatError: 12bf.

   * The new, longer *note str(): 44f. value on floats may break
     doctests which rely on the old output format.

   * In *note subprocess.Popen: 199, the default value for 'close_fds'
     is now ‘True’ under Unix; under Windows, it is ‘True’ if the three
     standard streams are set to ‘None’, ‘False’ otherwise.  Previously,
     'close_fds' was always ‘False’ by default, which produced difficult
     to solve bugs or race conditions when open file descriptors would
     leak into the child process.

   * Support for legacy HTTP 0.9 has been removed from *note
     urllib.request: 10b. and *note http.client: 6f.  Such support is
     still present on the server side (in *note http.server: 72.).

     (Contributed by Antoine Pitrou, bpo-10711(5).)

   * SSL sockets in timeout mode now raise *note socket.timeout: 83a.
     when a timeout occurs, rather than a generic *note SSLError: 12c0.

     (Contributed by Antoine Pitrou, bpo-10272(6).)

   * The misleading functions ‘PyEval_AcquireLock()’ and
     ‘PyEval_ReleaseLock()’ have been officially deprecated.  The
     thread-state aware APIs (such as *note PyEval_SaveThread(): 3ab.
     and *note PyEval_RestoreThread(): 3ac.) should be used instead.

   * Due to security risks, ‘asyncore.handle_accept()’ has been
     deprecated, and a new function, ‘asyncore.handle_accepted()’, was
     added to replace it.

     (Contributed by Giampaolo Rodola in bpo-6706(7).)

   * Due to the new *note GIL: 159. implementation,
     ‘PyEval_InitThreads()’ cannot be called before *note
     Py_Initialize(): 8b4. anymore.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8990

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5675

   (3) https://codereview.appspot.com/53094

   (4) https://bugs.python.org/issue?@action=redirect&bpo=10783

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10711

   (6) https://bugs.python.org/issue?@action=redirect&bpo=10272

   (7) https://bugs.python.org/issue?@action=redirect&bpo=6706


File: python.info,  Node: What’s New In Python 3 1,  Next: What’s New In Python 3 0,  Prev: What’s New In Python 3 2,  Up: What’s New in Python

1.13 What’s New In Python 3.1
=============================


Author: Raymond Hettinger

This article explains the new features in Python 3.1, compared to 3.0.
Python 3.1 was released on June 27, 2009.

* Menu:

* PEP 372; Ordered Dictionaries: PEP 372 Ordered Dictionaries.
* PEP 378; Format Specifier for Thousands Separator: PEP 378 Format Specifier for Thousands Separator.
* Other Language Changes: Other Language Changes<13>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<2>.
* Optimizations: Optimizations<12>.
* IDLE: IDLE<2>.
* Build and C API Changes: Build and C API Changes<6>.
* Porting to Python 3.1: Porting to Python 3 1.


File: python.info,  Node: PEP 372 Ordered Dictionaries,  Next: PEP 378 Format Specifier for Thousands Separator,  Up: What’s New In Python 3 1

1.13.1 PEP 372: Ordered Dictionaries
------------------------------------

Regular Python dictionaries iterate over key/value pairs in arbitrary
order.  Over the years, a number of authors have written alternative
implementations that remember the order that the keys were originally
inserted.  Based on the experiences from those implementations, a new
*note collections.OrderedDict: 5de. class has been introduced.

The OrderedDict API is substantially the same as regular dictionaries
but will iterate over keys and values in a guaranteed order depending on
when a key was first inserted.  If a new entry overwrites an existing
entry, the original insertion position is left unchanged.  Deleting an
entry and reinserting it will move it to the end.

The standard library now supports use of ordered dictionaries in several
modules.  The *note configparser: 22. module uses them by default.  This
lets configuration files be read, modified, and then written back in
their original order.  The '_asdict()' method for *note
collections.namedtuple(): 1ca. now returns an ordered dictionary with
the values appearing in the same order as the underlying tuple indices.
The *note json: 82. module is being built-out with an
'object_pairs_hook' to allow OrderedDicts to be built by the decoder.
Support was also added for third-party tools like PyYAML(1).

See also
........

PEP 372(2) - Ordered Dictionaries

     PEP written by Armin Ronacher and Raymond Hettinger.
     Implementation written by Raymond Hettinger.

Since an ordered dictionary remembers its insertion order, it can be
used in conjunction with sorting to make a sorted dictionary:

     >>> # regular unsorted dictionary
     >>> d = {'banana': 3, 'apple':4, 'pear': 1, 'orange': 2}

     >>> # dictionary sorted by key
     >>> OrderedDict(sorted(d.items(), key=lambda t: t[0]))
     OrderedDict([('apple', 4), ('banana', 3), ('orange', 2), ('pear', 1)])

     >>> # dictionary sorted by value
     >>> OrderedDict(sorted(d.items(), key=lambda t: t[1]))
     OrderedDict([('pear', 1), ('orange', 2), ('banana', 3), ('apple', 4)])

     >>> # dictionary sorted by length of the key string
     >>> OrderedDict(sorted(d.items(), key=lambda t: len(t[0])))
     OrderedDict([('pear', 1), ('apple', 4), ('orange', 2), ('banana', 3)])

The new sorted dictionaries maintain their sort order when entries are
deleted.  But when new keys are added, the keys are appended to the end
and the sort is not maintained.

   ---------- Footnotes ----------

   (1) https://pyyaml.org/

   (2) https://peps.python.org/pep-0372/


File: python.info,  Node: PEP 378 Format Specifier for Thousands Separator,  Next: Other Language Changes<13>,  Prev: PEP 372 Ordered Dictionaries,  Up: What’s New In Python 3 1

1.13.2 PEP 378: Format Specifier for Thousands Separator
--------------------------------------------------------

The built-in *note format(): 622. function and the *note str.format():
624. method use a mini-language that now includes a simple, non-locale
aware way to format a number with a thousands separator.  That provides
a way to humanize a program’s output, improving its professional
appearance and readability:

     >>> format(1234567, ',d')
     '1,234,567'
     >>> format(1234567.89, ',.2f')
     '1,234,567.89'
     >>> format(12345.6 + 8901234.12j, ',f')
     '12,345.600000+8,901,234.120000j'
     >>> format(Decimal('1234567.89'), ',f')
     '1,234,567.89'

The supported types are *note int: 257, *note float: 2f7, *note complex:
2f8. and *note decimal.Decimal: 29d.

Discussions are underway about how to specify alternative separators
like dots, spaces, apostrophes, or underscores.  Locale-aware
applications should use the existing 'n' format specifier which already
has some support for thousands separators.

See also
........

PEP 378(1) - Format Specifier for Thousands Separator

     PEP written by Raymond Hettinger and implemented by Eric Smith and
     Mark Dickinson.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0378/


File: python.info,  Node: Other Language Changes<13>,  Next: New Improved and Deprecated Modules<2>,  Prev: PEP 378 Format Specifier for Thousands Separator,  Up: What’s New In Python 3 1

1.13.3 Other Language Changes
-----------------------------

Some smaller changes made to the core Python language are:

   * Directories and zip archives containing a ‘__main__.py’ file can
     now be executed directly by passing their name to the interpreter.
     The directory/zipfile is automatically inserted as the first entry
     in sys.path.  (Suggestion and initial patch by Andy Chu; revised
     patch by Phillip J. Eby and Nick Coghlan; bpo-1739468(1).)

   * The *note int(): 257. type gained a ‘bit_length’ method that
     returns the number of bits necessary to represent its argument in
     binary:

          >>> n = 37
          >>> bin(37)
          '0b100101'
          >>> n.bit_length()
          6
          >>> n = 2**123-1
          >>> n.bit_length()
          123
          >>> (n+1).bit_length()
          124

     (Contributed by Fredrik Johansson, Victor Stinner, Raymond
     Hettinger, and Mark Dickinson; bpo-3439(2).)

   * The fields in *note format(): 622. strings can now be automatically
     numbered:

          >>> 'Sir {} of {}'.format('Gallahad', 'Camelot')
          'Sir Gallahad of Camelot'

     Formerly, the string would have required numbered fields such as:
     ‘'Sir {0} of {1}'’.

     (Contributed by Eric Smith; bpo-5237(3).)

   * The ‘string.maketrans()’ function is deprecated and is replaced by
     new static methods, *note bytes.maketrans(): 12bb. and *note
     bytearray.maketrans(): 12bc.  This change solves the confusion
     around which types were supported by the *note string: d3. module.
     Now, *note str: 44f, *note bytes: 1c2, and *note bytearray: 2ea.
     each have their own 'maketrans' and 'translate' methods with
     intermediate translation tables of the appropriate type.

     (Contributed by Georg Brandl; bpo-5675(4).)

   * The syntax of the *note with: 5d5. statement now allows multiple
     context managers in a single statement:

          >>> with open('mylog.txt') as infile, open('a.out', 'w') as outfile:
          ...     for line in infile:
          ...         if '<critical>' in line:
          ...             outfile.write(line)

     With the new syntax, the ‘contextlib.nested()’ function is no
     longer needed and is now deprecated.

     (Contributed by Georg Brandl and Mattias Brändström; appspot issue
     53094(5).)

   * ‘round(x, n)’ now returns an integer if 'x' is an integer.
     Previously it returned a float:

          >>> round(1123, -2)
          1100

     (Contributed by Mark Dickinson; bpo-4707(6).)

   * Python now uses David Gay’s algorithm for finding the shortest
     floating-point representation that doesn’t change its value.  This
     should help mitigate some of the confusion surrounding binary
     floating-point numbers.

     The significance is easily seen with a number like ‘1.1’ which does
     not have an exact equivalent in binary floating point.  Since there
     is no exact equivalent, an expression like ‘float('1.1')’ evaluates
     to the nearest representable value which is ‘0x1.199999999999ap+0’
     in hex or ‘1.100000000000000088817841970012523233890533447265625’
     in decimal.  That nearest value was and still is used in subsequent
     floating-point calculations.

     What is new is how the number gets displayed.  Formerly, Python
     used a simple approach.  The value of ‘repr(1.1)’ was computed as
     ‘format(1.1, '.17g')’ which evaluated to ‘'1.1000000000000001'’.
     The advantage of using 17 digits was that it relied on IEEE-754
     guarantees to assure that ‘eval(repr(1.1))’ would round-trip
     exactly to its original value.  The disadvantage is that many
     people found the output to be confusing (mistaking intrinsic
     limitations of binary floating-point representation as being a
     problem with Python itself).

     The new algorithm for ‘repr(1.1)’ is smarter and returns ‘'1.1'’.
     Effectively, it searches all equivalent string representations
     (ones that get stored with the same underlying float value) and
     returns the shortest representation.

     The new algorithm tends to emit cleaner representations when
     possible, but it does not change the underlying values.  So, it is
     still the case that ‘1.1 + 2.2 != 3.3’ even though the
     representations may suggest otherwise.

     The new algorithm depends on certain features in the underlying
     floating-point implementation.  If the required features are not
     found, the old algorithm will continue to be used.  Also, the text
     pickle protocols assure cross-platform portability by using the old
     algorithm.

     (Contributed by Eric Smith and Mark Dickinson; bpo-1580(7))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1739468

   (2) https://bugs.python.org/issue?@action=redirect&bpo=3439

   (3) https://bugs.python.org/issue?@action=redirect&bpo=5237

   (4) https://bugs.python.org/issue?@action=redirect&bpo=5675

   (5) https://codereview.appspot.com/53094

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4707

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1580


File: python.info,  Node: New Improved and Deprecated Modules<2>,  Next: Optimizations<12>,  Prev: Other Language Changes<13>,  Up: What’s New In Python 3 1

1.13.4 New, Improved, and Deprecated Modules
--------------------------------------------

   * Added a *note collections.Counter: 10d5. class to support
     convenient counting of unique items in a sequence or iterable:

          >>> Counter(['red', 'blue', 'red', 'green', 'blue', 'blue'])
          Counter({'blue': 3, 'red': 2, 'green': 1})

     (Contributed by Raymond Hettinger; bpo-1696199(1).)

   * Added a new module, *note tkinter.ttk: f9. for access to the Tk
     themed widget set.  The basic idea of ttk is to separate, to the
     extent possible, the code implementing a widget’s behavior from the
     code implementing its appearance.

     (Contributed by Guilherme Polo; bpo-2983(2).)

   * The *note gzip.GzipFile: 41d. and *note bz2.BZ2File: 86d. classes
     now support the context management protocol:

          >>> # Automatically close file after writing
          >>> with gzip.GzipFile(filename, "wb") as f:
          ...     f.write(b"xxx")

     (Contributed by Antoine Pitrou.)

   * The *note decimal: 36. module now supports methods for creating a
     decimal object from a binary *note float: 2f7.  The conversion is
     exact but can sometimes be surprising:

          >>> Decimal.from_float(1.1)
          Decimal('1.100000000000000088817841970012523233890533447265625')

     The long decimal result shows the actual binary fraction being
     stored for '1.1'.  The fraction has many digits because '1.1'
     cannot be exactly represented in binary.

     (Contributed by Raymond Hettinger and Mark Dickinson.)

   * The *note itertools: 81. module grew two new functions.  The *note
     itertools.combinations_with_replacement(): 12c8. function is one of
     four for generating combinatorics including permutations and
     Cartesian products.  The *note itertools.compress(): 12c9. function
     mimics its namesake from APL. Also, the existing *note
     itertools.count(): 12ca. function now has an optional 'step'
     argument and can accept any type of counting sequence including
     *note fractions.Fraction: 1e7. and *note decimal.Decimal: 29d.:

          >>> [p+q for p,q in combinations_with_replacement('LOVE', 2)]
          ['LL', 'LO', 'LV', 'LE', 'OO', 'OV', 'OE', 'VV', 'VE', 'EE']

          >>> list(compress(data=range(10), selectors=[0,0,1,1,0,1,0,1,0,0]))
          [2, 3, 5, 7]

          >>> c = count(start=Fraction(1,2), step=Fraction(1,6))
          >>> [next(c), next(c), next(c), next(c)]
          [Fraction(1, 2), Fraction(2, 3), Fraction(5, 6), Fraction(1, 1)]

     (Contributed by Raymond Hettinger.)

   * *note collections.namedtuple(): 1ca. now supports a keyword
     argument 'rename' which lets invalid fieldnames be automatically
     converted to positional names in the form _0, _1, etc.  This is
     useful when the field names are being created by an external source
     such as a CSV header, SQL field list, or user input:

          >>> query = input()
          SELECT region, dept, count(*) FROM main GROUPBY region, dept

          >>> cursor.execute(query)
          >>> query_fields = [desc[0] for desc in cursor.description]
          >>> UserQuery = namedtuple('UserQuery', query_fields, rename=True)
          >>> pprint.pprint([UserQuery(*row) for row in cursor])
          [UserQuery(region='South', dept='Shipping', _2=185),
           UserQuery(region='North', dept='Accounting', _2=37),
           UserQuery(region='West', dept='Sales', _2=419)]

     (Contributed by Raymond Hettinger; bpo-1818(3).)

   * The *note re.sub(): 2a3, *note re.subn(): 2a4. and *note
     re.split(): 2a2. functions now accept a flags parameter.

     (Contributed by Gregory Smith.)

   * The *note logging: 87. module now implements a simple *note
     logging.NullHandler: 12cb. class for applications that are not
     using logging but are calling library code that does.  Setting-up a
     null handler will suppress spurious warnings such as “No handlers
     could be found for logger foo”:

          >>> h = logging.NullHandler()
          >>> logging.getLogger("foo").addHandler(h)

     (Contributed by Vinay Sajip; bpo-4384(4)).

   * The *note runpy: be. module which supports the ‘-m’ command line
     switch now supports the execution of packages by looking for and
     executing a ‘__main__’ submodule when a package name is supplied.

     (Contributed by Andi Vajda; bpo-4195(5).)

   * The *note pdb: a5. module can now access and display source code
     loaded via *note zipimport: 132. (or any other conformant PEP
     302(6) loader).

     (Contributed by Alexander Belopolsky; bpo-4201(7).)

   * *note functools.partial: 417. objects can now be pickled.

     (Suggested by Antoine Pitrou and Jesse Noller.  Implemented by Jack
     Diederich; bpo-5228(8).)

   * Add *note pydoc: b5. help topics for symbols so that ‘help('@')’
     works as expected in the interactive environment.

     (Contributed by David Laban; bpo-4739(9).)

   * The *note unittest: 106. module now supports skipping individual
     tests or classes of tests.  And it supports marking a test as an
     expected failure, a test that is known to be broken, but shouldn’t
     be counted as a failure on a TestResult:

          class TestGizmo(unittest.TestCase):

              @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
              def test_gizmo_on_windows(self):
                  ...

              @unittest.expectedFailure
              def test_gimzo_without_required_library(self):
                  ...

     Also, tests for exceptions have been builtout to work with context
     managers using the *note with: 5d5. statement:

          def test_division_by_zero(self):
              with self.assertRaises(ZeroDivisionError):
                  x / 0

     In addition, several new assertion methods were added including
     *note assertSetEqual(): 12cc, *note assertDictEqual(): 12cd,
     ‘assertDictContainsSubset()’, *note assertListEqual(): 12ce, *note
     assertTupleEqual(): 12cf, *note assertSequenceEqual(): 12d0, *note
     assertRaisesRegexp(): 532, *note assertIsNone(): 12d1, and *note
     assertIsNotNone(): 12d2.

     (Contributed by Benjamin Peterson and Antoine Pitrou.)

   * The *note io: 7f. module has three new constants for the *note
     seek(): 12d3. method: *note SEEK_SET: 12d4, *note SEEK_CUR: 12d5,
     and *note SEEK_END: 12d6.

   * The *note sys.version_info: 6a3. tuple is now a named tuple:

          >>> sys.version_info
          sys.version_info(major=3, minor=1, micro=0, releaselevel='alpha', serial=2)

     (Contributed by Ross Light; bpo-4285(10).)

   * The ‘nntplib’ and *note imaplib: 74. modules now support IPv6.

     (Contributed by Derek Morr; bpo-1655(11) and bpo-1664(12).)

   * The *note pickle: a6. module has been adapted for better
     interoperability with Python 2.x when used with protocol 2 or
     lower.  The reorganization of the standard library changed the
     formal reference for many objects.  For example, ‘__builtin__.set’
     in Python 2 is called ‘builtins.set’ in Python 3.  This change
     confounded efforts to share data between different versions of
     Python.  But now when protocol 2 or lower is selected, the pickler
     will automatically use the old Python 2 names for both loading and
     dumping.  This remapping is turned-on by default but can be
     disabled with the 'fix_imports' option:

          >>> s = {1, 2, 3}
          >>> pickle.dumps(s, protocol=0)
          b'c__builtin__\nset\np0\n((lp1\nL1L\naL2L\naL3L\natp2\nRp3\n.'
          >>> pickle.dumps(s, protocol=0, fix_imports=False)
          b'cbuiltins\nset\np0\n((lp1\nL1L\naL2L\naL3L\natp2\nRp3\n.'

     An unfortunate but unavoidable side-effect of this change is that
     protocol 2 pickles produced by Python 3.1 won’t be readable with
     Python 3.0.  The latest pickle protocol, protocol 3, should be used
     when migrating data between Python 3.x implementations, as it
     doesn’t attempt to remain compatible with Python 2.x.

     (Contributed by Alexandre Vassalotti and Antoine Pitrou,
     bpo-6137(13).)

   * A new module, *note importlib: 77. was added.  It provides a
     complete, portable, pure Python reference implementation of the
     *note import: 5e5. statement and its counterpart, the *note
     __import__(): 8dd. function.  It represents a substantial step
     forward in documenting and defining the actions that take place
     during imports.

     (Contributed by Brett Cannon.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1696199

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2983

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1818

   (4) https://bugs.python.org/issue?@action=redirect&bpo=4384

   (5) https://bugs.python.org/issue?@action=redirect&bpo=4195

   (6) https://peps.python.org/pep-0302/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=4201

   (8) https://bugs.python.org/issue?@action=redirect&bpo=5228

   (9) https://bugs.python.org/issue?@action=redirect&bpo=4739

   (10) https://bugs.python.org/issue?@action=redirect&bpo=4285

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1655

   (12) https://bugs.python.org/issue?@action=redirect&bpo=1664

   (13) https://bugs.python.org/issue?@action=redirect&bpo=6137


File: python.info,  Node: Optimizations<12>,  Next: IDLE<2>,  Prev: New Improved and Deprecated Modules<2>,  Up: What’s New In Python 3 1

1.13.5 Optimizations
--------------------

Major performance enhancements have been added:

   * The new I/O library (as defined in PEP 3116(1)) was mostly written
     in Python and quickly proved to be a problematic bottleneck in
     Python 3.0.  In Python 3.1, the I/O library has been entirely
     rewritten in C and is 2 to 20 times faster depending on the task at
     hand.  The pure Python version is still available for
     experimentation purposes through the ‘_pyio’ module.

     (Contributed by Amaury Forgeot d’Arc and Antoine Pitrou.)

   * Added a heuristic so that tuples and dicts containing only
     untrackable objects are not tracked by the garbage collector.  This
     can reduce the size of collections and therefore the garbage
     collection overhead on long-running programs, depending on their
     particular use of datatypes.

     (Contributed by Antoine Pitrou, bpo-4688(2).)

   * Enabling a configure option named ‘--with-computed-gotos’ on
     compilers that support it (notably: gcc, SunPro, icc), the bytecode
     evaluation loop is compiled with a new dispatch mechanism which
     gives speedups of up to 20%, depending on the system, the compiler,
     and the benchmark.

     (Contributed by Antoine Pitrou along with a number of other
     participants, bpo-4753(3)).

   * The decoding of UTF-8, UTF-16 and LATIN-1 is now two to four times
     faster.

     (Contributed by Antoine Pitrou and Amaury Forgeot d’Arc,
     bpo-4868(4).)

   * The *note json: 82. module now has a C extension to substantially
     improve its performance.  In addition, the API was modified so that
     json works only with *note str: 44f, not with *note bytes: 1c2.
     That change makes the module closely match the JSON
     specification(5) which is defined in terms of Unicode.

     (Contributed by Bob Ippolito and converted to Py3.1 by Antoine
     Pitrou and Benjamin Peterson; bpo-4136(6).)

   * Unpickling now interns the attribute names of pickled objects.
     This saves memory and allows pickles to be smaller.

     (Contributed by Jake McGuire and Antoine Pitrou; bpo-5084(7).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3116/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4688

   (3) https://bugs.python.org/issue?@action=redirect&bpo=4753

   (4) https://bugs.python.org/issue?@action=redirect&bpo=4868

   (5) https://json.org/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4136

   (7) https://bugs.python.org/issue?@action=redirect&bpo=5084


File: python.info,  Node: IDLE<2>,  Next: Build and C API Changes<6>,  Prev: Optimizations<12>,  Up: What’s New In Python 3 1

1.13.6 IDLE
-----------

   * IDLE’s format menu now provides an option to strip trailing
     whitespace from a source file.

     (Contributed by Roger D. Serwy; bpo-5150(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5150


File: python.info,  Node: Build and C API Changes<6>,  Next: Porting to Python 3 1,  Prev: IDLE<2>,  Up: What’s New In Python 3 1

1.13.7 Build and C API Changes
------------------------------

Changes to Python’s build process and to the C API include:

   * Integers are now stored internally either in base ‘2**15’ or in
     base ‘2**30’, the base being determined at build time.  Previously,
     they were always stored in base ‘2**15’.  Using base ‘2**30’ gives
     significant performance improvements on 64-bit machines, but
     benchmark results on 32-bit machines have been mixed.  Therefore,
     the default is to use base ‘2**30’ on 64-bit machines and base
     ‘2**15’ on 32-bit machines; on Unix, there’s a new configure option
     ‘--enable-big-digits’ that can be used to override this default.

     Apart from the performance improvements this change should be
     invisible to end users, with one exception: for testing and
     debugging purposes there’s a new *note sys.int_info: 12da. that
     provides information about the internal format, giving the number
     of bits per digit and the size in bytes of the C type used to store
     each digit:

          >>> import sys
          >>> sys.int_info
          sys.int_info(bits_per_digit=30, sizeof_digit=4)

     (Contributed by Mark Dickinson; bpo-4258(1).)

   * The *note PyLong_AsUnsignedLongLong(): 12db. function now handles a
     negative 'pylong' by raising *note OverflowError: 888. instead of
     *note TypeError: 2c3.

     (Contributed by Mark Dickinson and Lisandro Dalcrin; bpo-5175(2).)

   * Deprecated ‘PyNumber_Int()’.  Use *note PyNumber_Long(): a76.
     instead.

     (Contributed by Mark Dickinson; bpo-4910(3).)

   * Added a new *note PyOS_string_to_double(): 12dc. function to
     replace the deprecated functions ‘PyOS_ascii_strtod()’ and
     ‘PyOS_ascii_atof()’.

     (Contributed by Mark Dickinson; bpo-5914(4).)

   * Added *note PyCapsule: 12b9. as a replacement for the ‘PyCObject’
     API. The principal difference is that the new type has a well
     defined interface for passing typing safety information and a less
     complicated signature for calling a destructor.  The old type had a
     problematic API and is now deprecated.

     (Contributed by Larry Hastings; bpo-5630(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4258

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5175

   (3) https://bugs.python.org/issue?@action=redirect&bpo=4910

   (4) https://bugs.python.org/issue?@action=redirect&bpo=5914

   (5) https://bugs.python.org/issue?@action=redirect&bpo=5630


File: python.info,  Node: Porting to Python 3 1,  Prev: Build and C API Changes<6>,  Up: What’s New In Python 3 1

1.13.8 Porting to Python 3.1
----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code:

   * The new floating-point string representations can break existing
     doctests.  For example:

          def e():
              '''Compute the base of natural logarithms.

              >>> e()
              2.7182818284590451

              '''
              return sum(1/math.factorial(x) for x in reversed(range(30)))

          doctest.testmod()

          **********************************************************************
          Failed example:
              e()
          Expected:
              2.7182818284590451
          Got:
              2.718281828459045
          **********************************************************************

   * The automatic name remapping in the pickle module for protocol 2 or
     lower can make Python 3.1 pickles unreadable in Python 3.0.  One
     solution is to use protocol 3.  Another solution is to set the
     'fix_imports' option to ‘False’.  See the discussion above for more
     details.


File: python.info,  Node: What’s New In Python 3 0,  Next: What’s New in Python 2 7,  Prev: What’s New In Python 3 1,  Up: What’s New in Python

1.14 What’s New In Python 3.0
=============================


Author: Guido van Rossum

This article explains the new features in Python 3.0, compared to 2.6.
Python 3.0, also known as “Python 3000” or “Py3K”, is the first ever
'intentionally backwards incompatible' Python release.  Python 3.0 was
released on December 3, 2008.  There are more changes than in a typical
release, and more that are important for all Python users.
Nevertheless, after digesting the changes, you’ll find that Python
really hasn’t changed all that much – by and large, we’re mostly fixing
well-known annoyances and warts, and removing a lot of old cruft.

This article doesn’t attempt to provide a complete specification of all
new features, but instead tries to give a convenient overview.  For full
details, you should refer to the documentation for Python 3.0, and/or
the many PEPs referenced in the text.  If you want to understand the
complete implementation and design rationale for a particular feature,
PEPs usually have more details than the regular documentation; but note
that PEPs usually are not kept up-to-date once a feature has been fully
implemented.

Due to time constraints this document is not as complete as it should
have been.  As always for a new release, the ‘Misc/NEWS’ file in the
source distribution contains a wealth of detailed information about
every small thing that was changed.

* Menu:

* Common Stumbling Blocks::
* Overview Of Syntax Changes::
* Changes Already Present In Python 2.6: Changes Already Present In Python 2 6.
* Library Changes::
* PEP 3101; A New Approach To String Formatting: PEP 3101 A New Approach To String Formatting.
* Changes To Exceptions::
* Miscellaneous Other Changes::
* Build and C API Changes: Build and C API Changes<7>.
* Performance::
* Porting To Python 3.0: Porting To Python 3 0.


File: python.info,  Node: Common Stumbling Blocks,  Next: Overview Of Syntax Changes,  Up: What’s New In Python 3 0

1.14.1 Common Stumbling Blocks
------------------------------

This section lists those few changes that are most likely to trip you up
if you’re used to Python 2.5.

* Menu:

* Print Is A Function::
* Views And Iterators Instead Of Lists::
* Ordering Comparisons::
* Integers::
* Text Vs. Data Instead Of Unicode Vs. 8-bit: Text Vs Data Instead Of Unicode Vs 8-bit.


File: python.info,  Node: Print Is A Function,  Next: Views And Iterators Instead Of Lists,  Up: Common Stumbling Blocks

1.14.1.1 Print Is A Function
............................

The ‘print’ statement has been replaced with a *note print(): fae.
function, with keyword arguments to replace most of the special syntax
of the old ‘print’ statement ( PEP 3105(1)).  Examples:

     Old: print "The answer is", 2*2
     New: print("The answer is", 2*2)

     Old: print x,           # Trailing comma suppresses newline
     New: print(x, end=" ")  # Appends a space instead of a newline

     Old: print              # Prints a newline
     New: print()            # You must call the function!

     Old: print >>sys.stderr, "fatal error"
     New: print("fatal error", file=sys.stderr)

     Old: print (x, y)       # prints repr((x, y))
     New: print((x, y))      # Not the same as print(x, y)!

You can also customize the separator between items, e.g.:

     print("There are <", 2**32, "> possibilities!", sep="")

which produces:

     There are <4294967296> possibilities!

Note:

   * The *note print(): fae. function doesn’t support the “softspace”
     feature of the old ‘print’ statement.  For example, in Python 2.x,
     ‘print "A\n", "B"’ would write ‘"A\nB\n"’; but in Python 3.0,
     ‘print("A\n", "B")’ writes ‘"A\n B\n"’.

   * Initially, you’ll be finding yourself typing the old ‘print x’ a
     lot in interactive mode.  Time to retrain your fingers to type
     ‘print(x)’ instead!

   * When using the ‘2to3’ source-to-source conversion tool, all ‘print’
     statements are automatically converted to *note print(): fae.
     function calls, so this is mostly a non-issue for larger projects.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3105/


File: python.info,  Node: Views And Iterators Instead Of Lists,  Next: Ordering Comparisons,  Prev: Print Is A Function,  Up: Common Stumbling Blocks

1.14.1.2 Views And Iterators Instead Of Lists
.............................................

Some well-known APIs no longer return lists:

   * *note dict: 256. methods *note dict.keys(): 7d1, *note
     dict.items(): 7d3. and *note dict.values(): 7d2. return “views”
     instead of lists.  For example, this no longer works: ‘k =
     d.keys(); k.sort()’.  Use ‘k = sorted(d)’ instead (this works in
     Python 2.5 too and is just as efficient).

   * Also, the ‘dict.iterkeys()’, ‘dict.iteritems()’ and
     ‘dict.itervalues()’ methods are no longer supported.

   * *note map(): 86a. and *note filter(): 86b. return iterators.  If
     you really need a list and the input sequences are all of equal
     length, a quick fix is to wrap ‘map()’ in *note list(): 614, e.g.
     ‘list(map(...))’, but a better fix is often to use a list
     comprehension (especially when the original code uses *note lambda:
     12e4.), or rewriting the code so it doesn’t need a list at all.
     Particularly tricky is ‘map()’ invoked for the side effects of the
     function; the correct transformation is to use a regular *note for:
     2f2. loop (since creating a list would just be wasteful).

     If the input sequences are not of equal length, *note map(): 86a.
     will stop at the termination of the shortest of the sequences.  For
     full compatibility with ‘map()’ from Python 2.x, also wrap the
     sequences in *note itertools.zip_longest(): 12e5, e.g.  ‘map(func,
     *sequences)’ becomes ‘list(map(func,
     itertools.zip_longest(*sequences)))’.

   * *note range(): 94d. now behaves like ‘xrange()’ used to behave,
     except it works with values of arbitrary size.  The latter no
     longer exists.

   * *note zip(): 7d4. now returns an iterator.


File: python.info,  Node: Ordering Comparisons,  Next: Integers,  Prev: Views And Iterators Instead Of Lists,  Up: Common Stumbling Blocks

1.14.1.3 Ordering Comparisons
.............................

Python 3.0 has simplified the rules for ordering comparisons:

   * The ordering comparison operators (‘<’, ‘<=’, ‘>=’, ‘>’) raise a
     TypeError exception when the operands don’t have a meaningful
     natural ordering.  Thus, expressions like ‘1 < ''’, ‘0 > None’ or
     ‘len <= len’ are no longer valid, and e.g.  ‘None < None’ raises
     *note TypeError: 2c3. instead of returning ‘False’.  A corollary is
     that sorting a heterogeneous list no longer makes sense – all the
     elements must be comparable to each other.  Note that this does not
     apply to the ‘==’ and ‘!=’ operators: objects of different
     incomparable types always compare unequal to each other.

   * *note sorted(): bed. and *note list.sort(): bee. no longer accept
     the 'cmp' argument providing a comparison function.  Use the 'key'
     argument instead.  N.B. the 'key' and 'reverse' arguments are now
     “keyword-only”.

   * The ‘cmp()’ function should be treated as gone, and the ‘__cmp__()’
     special method is no longer supported.  Use *note __lt__(): 12e7.
     for sorting, *note __eq__(): b13. with *note __hash__(): b14, and
     other rich comparisons as needed.  (If you really need the ‘cmp()’
     functionality, you could use the expression ‘(a > b) - (a < b)’ as
     the equivalent for ‘cmp(a, b)’.)


File: python.info,  Node: Integers,  Next: Text Vs Data Instead Of Unicode Vs 8-bit,  Prev: Ordering Comparisons,  Up: Common Stumbling Blocks

1.14.1.4 Integers
.................

   * PEP 237(1): Essentially, ‘long’ renamed to *note int: 257.  That
     is, there is only one built-in integral type, named ‘int’; but it
     behaves mostly like the old ‘long’ type.

   * PEP 238(2): An expression like ‘1/2’ returns a float.  Use ‘1//2’
     to get the truncating behavior.  (The latter syntax has existed for
     years, at least since Python 2.2.)

   * The ‘sys.maxint’ constant was removed, since there is no longer a
     limit to the value of integers.  However, *note sys.maxsize: 120a.
     can be used as an integer larger than any practical list or string
     index.  It conforms to the implementation’s “natural” integer size
     and is typically the same as ‘sys.maxint’ in previous releases on
     the same platform (assuming the same build options).

   * The *note repr(): 803. of a long integer doesn’t include the
     trailing ‘L’ anymore, so code that unconditionally strips that
     character will chop off the last digit instead.  (Use *note str():
     44f. instead.)

   * Octal literals are no longer of the form ‘0720’; use ‘0o720’
     instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0237/

   (2) https://peps.python.org/pep-0238/


File: python.info,  Node: Text Vs Data Instead Of Unicode Vs 8-bit,  Prev: Integers,  Up: Common Stumbling Blocks

1.14.1.5 Text Vs. Data Instead Of Unicode Vs. 8-bit
...................................................

Everything you thought you knew about binary data and Unicode has
changed.

   * Python 3.0 uses the concepts of 'text' and (binary) 'data' instead
     of Unicode strings and 8-bit strings.  All text is Unicode; however
     'encoded' Unicode is represented as binary data.  The type used to
     hold text is *note str: 44f, the type used to hold data is *note
     bytes: 1c2.  The biggest difference with the 2.x situation is that
     any attempt to mix text and data in Python 3.0 raises *note
     TypeError: 2c3, whereas if you were to mix Unicode and 8-bit
     strings in Python 2.x, it would work if the 8-bit string happened
     to contain only 7-bit (ASCII) bytes, but you would get *note
     UnicodeDecodeError: a20. if it contained non-ASCII values.  This
     value-specific behavior has caused numerous sad faces over the
     years.

   * As a consequence of this change in philosophy, pretty much all code
     that uses Unicode, encodings or binary data most likely has to
     change.  The change is for the better, as in the 2.x world there
     were numerous bugs having to do with mixing encoded and unencoded
     text.  To be prepared in Python 2.x, start using ‘unicode’ for all
     unencoded text, and *note str: 44f. for binary or encoded data
     only.  Then the ‘2to3’ tool will do most of the work for you.

   * You can no longer use ‘u"..."’ literals for Unicode text.  However,
     you must use ‘b"..."’ literals for binary data.

   * As the *note str: 44f. and *note bytes: 1c2. types cannot be mixed,
     you must always explicitly convert between them.  Use *note
     str.encode(): 8de. to go from ‘str’ to ‘bytes’, and *note
     bytes.decode(): 8df. to go from ‘bytes’ to ‘str’.  You can also use
     ‘bytes(s, encoding=...)’ and ‘str(b, encoding=...)’, respectively.

   * Like *note str: 44f, the *note bytes: 1c2. type is immutable.
     There is a separate 'mutable' type to hold buffered binary data,
     *note bytearray: 2ea.  Nearly all APIs that accept ‘bytes’ also
     accept ‘bytearray’.  The mutable API is based on *note
     collections.MutableSequence: 1a1.

   * All backslashes in raw string literals are interpreted literally.
     This means that ‘'\U'’ and ‘'\u'’ escapes in raw strings are not
     treated specially.  For example, ‘r'\u20ac'’ is a string of 6
     characters in Python 3.0, whereas in 2.6, ‘ur'\u20ac'’ was the
     single “euro” character.  (Of course, this change only affects raw
     string literals; the euro character is ‘'\u20ac'’ in Python 3.0.)

   * The built-in ‘basestring’ abstract type was removed.  Use *note
     str: 44f. instead.  The ‘str’ and *note bytes: 1c2. types don’t
     have functionality enough in common to warrant a shared base class.
     The ‘2to3’ tool (see below) replaces every occurrence of
     ‘basestring’ with ‘str’.

   * Files opened as text files (still the default mode for *note
     open(): 51f.) always use an encoding to map between strings (in
     memory) and bytes (on disk).  Binary files (opened with a ‘b’ in
     the mode argument) always use bytes in memory.  This means that if
     a file is opened using an incorrect mode or encoding, I/O will
     likely fail loudly, instead of silently producing incorrect data.
     It also means that even Unix users will have to specify the correct
     mode (text or binary) when opening a file.  There is a
     platform-dependent default encoding, which on Unixy platforms can
     be set with the ‘LANG’ environment variable (and sometimes also
     with some other platform-specific locale-related environment
     variables).  In many cases, but not all, the system default is
     UTF-8; you should never count on this default.  Any application
     reading or writing more than pure ASCII text should probably have a
     way to override the encoding.  There is no longer any need for
     using the encoding-aware streams in the *note codecs: 1b. module.

   * The initial values of *note sys.stdin: 540, *note sys.stdout: aec.
     and *note sys.stderr: 943. are now unicode-only text files (i.e.,
     they are instances of *note io.TextIOBase: 698.).  To read and
     write bytes data with these streams, you need to use their *note
     io.TextIOBase.buffer: 12ea. attribute.

   * Filenames are passed to and returned from APIs as (Unicode)
     strings.  This can present platform-specific problems because on
     some platforms filenames are arbitrary byte strings.  (On the other
     hand, on Windows filenames are natively stored as Unicode.)  As a
     work-around, most APIs (e.g.  *note open(): 51f. and many functions
     in the *note os: a1. module) that take filenames accept *note
     bytes: 1c2. objects as well as strings, and a few APIs have a way
     to ask for a ‘bytes’ return value.  Thus, *note os.listdir(): 113e.
     returns a list of ‘bytes’ instances if the argument is a ‘bytes’
     instance, and *note os.getcwdb(): aa0. returns the current working
     directory as a ‘bytes’ instance.  Note that when ‘os.listdir()’
     returns a list of strings, filenames that cannot be decoded
     properly are omitted rather than raising *note UnicodeError: 12eb.

   * Some system APIs like *note os.environ: 11fe. and *note sys.argv:
     12ab. can also present problems when the bytes made available by
     the system is not interpretable using the default encoding.
     Setting the ‘LANG’ variable and rerunning the program is probably
     the best approach.

   * PEP 3138(1): The *note repr(): 803. of a string no longer escapes
     non-ASCII characters.  It still escapes control characters and code
     points with non-printable status in the Unicode standard, however.

   * PEP 3120(2): The default source encoding is now UTF-8.

   * PEP 3131(3): Non-ASCII letters are now allowed in identifiers.
     (However, the standard library remains ASCII-only with the
     exception of contributor names in comments.)

   * The ‘StringIO’ and ‘cStringIO’ modules are gone.  Instead, import
     the *note io: 7f. module and use *note io.StringIO: f5e. or *note
     io.BytesIO: ed8. for text and data respectively.

   * See also the *note Unicode HOWTO: 12ec, which was updated for
     Python 3.0.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3138/

   (2) https://peps.python.org/pep-3120/

   (3) https://peps.python.org/pep-3131/


File: python.info,  Node: Overview Of Syntax Changes,  Next: Changes Already Present In Python 2 6,  Prev: Common Stumbling Blocks,  Up: What’s New In Python 3 0

1.14.2 Overview Of Syntax Changes
---------------------------------

This section gives a brief overview of every 'syntactic' change in
Python 3.0.

* Menu:

* New Syntax::
* Changed Syntax::
* Removed Syntax::


File: python.info,  Node: New Syntax,  Next: Changed Syntax,  Up: Overview Of Syntax Changes

1.14.2.1 New Syntax
...................

   * PEP 3107(1): Function argument and return value annotations.  This
     provides a standardized way of annotating a function’s parameters
     and return value.  There are no semantics attached to such
     annotations except that they can be introspected at runtime using
     the ‘__annotations__’ attribute.  The intent is to encourage
     experimentation through metaclasses, decorators or frameworks.

   * PEP 3102(2): Keyword-only arguments.  Named parameters occurring
     after ‘*args’ in the parameter list 'must' be specified using
     keyword syntax in the call.  You can also use a bare ‘*’ in the
     parameter list to indicate that you don’t accept a variable-length
     argument list, but you do have keyword-only arguments.

   * Keyword arguments are allowed after the list of base classes in a
     class definition.  This is used by the new convention for
     specifying a metaclass (see next section), but can be used for
     other purposes as well, as long as the metaclass supports it.

   * PEP 3104(3): *note nonlocal: 12ef. statement.  Using ‘nonlocal x’
     you can now assign directly to a variable in an outer (but
     non-global) scope.  ‘nonlocal’ is a new reserved word.

   * PEP 3132(4): Extended Iterable Unpacking.  You can now write things
     like ‘a, b, *rest = some_sequence’.  And even ‘*rest, a = stuff’.
     The ‘rest’ object is always a (possibly empty) list; the right-hand
     side may be any iterable.  Example:

          (a, *rest, b) = range(5)

     This sets 'a' to ‘0’, 'b' to ‘4’, and 'rest' to ‘[1, 2, 3]’.

   * Dictionary comprehensions: ‘{k: v for k, v in stuff}’ means the
     same thing as ‘dict(stuff)’ but is more flexible.  (This is PEP
     274(5) vindicated.  :-)

   * Set literals, e.g.  ‘{1, 2}’.  Note that ‘{}’ is an empty
     dictionary; use ‘set()’ for an empty set.  Set comprehensions are
     also supported; e.g., ‘{x for x in stuff}’ means the same thing as
     ‘set(stuff)’ but is more flexible.

   * New octal literals, e.g.  ‘0o720’ (already in 2.6).  The old octal
     literals (‘0720’) are gone.

   * New binary literals, e.g.  ‘0b1010’ (already in 2.6), and there is
     a new corresponding built-in function, *note bin(): 12f0.

   * Bytes literals are introduced with a leading ‘b’ or ‘B’, and there
     is a new corresponding built-in function, *note bytes(): 1c2.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3107/

   (2) https://peps.python.org/pep-3102/

   (3) https://peps.python.org/pep-3104/

   (4) https://peps.python.org/pep-3132/

   (5) https://peps.python.org/pep-0274/


File: python.info,  Node: Changed Syntax,  Next: Removed Syntax,  Prev: New Syntax,  Up: Overview Of Syntax Changes

1.14.2.2 Changed Syntax
.......................

   * PEP 3109(1) and PEP 3134(2): new *note raise: 5f0. statement
     syntax: ‘raise [EXPR [from EXPR]]’.  See below.

   * ‘as’ and *note with: 5d5. are now reserved words.  (Since 2.6,
     actually.)

   * ‘True’, ‘False’, and ‘None’ are reserved words.  (2.6 partially
     enforced the restrictions on ‘None’ already.)

   * Change from *note except: 18b. 'exc', 'var' to ‘except’ 'exc' ‘as’
     'var'.  See PEP 3110(3).

   * PEP 3115(4): New Metaclass Syntax.  Instead of:

          class C:
              __metaclass__ = M
              ...

     you must now use:

          class C(metaclass=M):
              ...

     The module-global ‘__metaclass__’ variable is no longer supported.
     (It was a crutch to make it easier to default to new-style classes
     without deriving every class from *note object: a9b.)

   * List comprehensions no longer support the syntactic form ‘[... for
     VAR in ITEM1, ITEM2, ...]’.  Use ‘[... for VAR in (ITEM1, ITEM2,
     ...)]’ instead.  Also note that list comprehensions have different
     semantics: they are closer to syntactic sugar for a generator
     expression inside a *note list(): 614. constructor, and in
     particular the loop control variables are no longer leaked into the
     surrounding scope.

   * The 'ellipsis' (‘...’) can be used as an atomic expression
     anywhere.  (Previously it was only allowed in slices.)  Also, it
     'must' now be spelled as ‘...’.  (Previously it could also be
     spelled as ‘. . .’, by a mere accident of the grammar.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3109/

   (2) https://peps.python.org/pep-3134/

   (3) https://peps.python.org/pep-3110/

   (4) https://peps.python.org/pep-3115/


File: python.info,  Node: Removed Syntax,  Prev: Changed Syntax,  Up: Overview Of Syntax Changes

1.14.2.3 Removed Syntax
.......................

   * PEP 3113(1): Tuple parameter unpacking removed.  You can no longer
     write ‘def foo(a, (b, c)): ...’.  Use ‘def foo(a, b_c): b, c = b_c’
     instead.

   * Removed backticks (use *note repr(): 803. instead).

   * Removed ‘<>’ (use ‘!=’ instead).

   * Removed keyword: *note exec(): 17f. is no longer a keyword; it
     remains as a function.  (Fortunately the function syntax was also
     accepted in 2.x.)  Also note that ‘exec()’ no longer takes a stream
     argument; instead of ‘exec(f)’ you can use ‘exec(f.read())’.

   * Integer literals no longer support a trailing ‘l’ or ‘L’.

   * String literals no longer support a leading ‘u’ or ‘U’.

   * The *note from: 12f3. 'module' *note import: 5e5. ‘*’ syntax is
     only allowed at the module level, no longer inside functions.

   * The only acceptable syntax for relative imports is ‘from .[MODULE]
     import NAME’.  All *note import: 5e5. forms not starting with ‘.’
     are interpreted as absolute imports.  ( PEP 328(2))

   * Classic classes are gone.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3113/

   (2) https://peps.python.org/pep-0328/


File: python.info,  Node: Changes Already Present In Python 2 6,  Next: Library Changes,  Prev: Overview Of Syntax Changes,  Up: What’s New In Python 3 0

1.14.3 Changes Already Present In Python 2.6
--------------------------------------------

Since many users presumably make the jump straight from Python 2.5 to
Python 3.0, this section reminds the reader of new features that were
originally designed for Python 3.0 but that were back-ported to Python
2.6.  The corresponding sections in *note What’s New in Python 2.6:
12f5. should be consulted for longer descriptions.

   * *note PEP 343; The ‘with’ statement: 12f6.  The *note with: 5d5.
     statement is now a standard feature and no longer needs to be
     imported from the *note __future__: 0.  Also check out *note
     Writing Context Managers: 12f7. and *note The contextlib module:
     12f8.

   * *note PEP 366; Explicit Relative Imports From a Main Module: 12f9.
     This enhances the usefulness of the *note -m: 5e4. option when the
     referenced module lives in a package.

   * *note PEP 370; Per-user site-packages Directory: 12fa.

   * *note PEP 371; The multiprocessing Package: 12fb.

   * *note PEP 3101; Advanced String Formatting: 12fc.  Note: the 2.6
     description mentions the *note format(): 622. method for both 8-bit
     and Unicode strings.  In 3.0, only the *note str: 44f. type (text
     strings with Unicode support) supports this method; the *note
     bytes: 1c2. type does not.  The plan is to eventually make this the
     only API for string formatting, and to start deprecating the ‘%’
     operator in Python 3.1.

   * *note PEP 3105; print As a Function: 12fd.  This is now a standard
     feature and no longer needs to be imported from *note __future__:
     0.  More details were given above.

   * *note PEP 3110; Exception-Handling Changes: 12fe.  The *note
     except: 18b. 'exc' ‘as’ 'var' syntax is now standard and ‘except’
     'exc', 'var' is no longer supported.  (Of course, the ‘as’ 'var'
     part is still optional.)

   * *note PEP 3112; Byte Literals: 12ff.  The ‘b"..."’ string literal
     notation (and its variants like ‘b'...'’, ‘b"""..."""’, and
     ‘br"..."’) now produces a literal of type *note bytes: 1c2.

   * *note PEP 3116; New I/O Library: 1300.  The *note io: 7f. module is
     now the standard way of doing file I/O. The built-in *note open():
     51f. function is now an alias for *note io.open(): 520. and has
     additional keyword arguments 'encoding', 'errors', 'newline' and
     'closefd'.  Also note that an invalid 'mode' argument now raises
     *note ValueError: 202, not *note IOError: 1090.  The binary file
     object underlying a text file object can be accessed as ‘f.buffer’
     (but beware that the text object maintains a buffer of itself in
     order to speed up the encoding and decoding operations).

   * *note PEP 3118; Revised Buffer Protocol: 1301.  The old builtin
     ‘buffer()’ is now really gone; the new builtin *note memoryview():
     2eb. provides (mostly) similar functionality.

   * *note PEP 3119; Abstract Base Classes: 1302.  The *note abc: 4.
     module and the ABCs defined in the *note collections: 1d. module
     plays a somewhat more prominent role in the language now, and
     built-in collection types like *note dict: 256. and *note list:
     614. conform to the *note collections.MutableMapping: 10f0. and
     *note collections.MutableSequence: 1a1. ABCs, respectively.

   * *note PEP 3127; Integer Literal Support and Syntax: 1303.  As
     mentioned above, the new octal literal notation is the only one
     supported, and binary literals have been added.

   * *note PEP 3129; Class Decorators: 1304.

   * *note PEP 3141; A Type Hierarchy for Numbers: 1305.  The *note
     numbers: 9e. module is another new use of ABCs, defining Python’s
     “numeric tower”.  Also note the new *note fractions: 5d. module
     which implements *note numbers.Rational: 1306.


File: python.info,  Node: Library Changes,  Next: PEP 3101 A New Approach To String Formatting,  Prev: Changes Already Present In Python 2 6,  Up: What’s New In Python 3 0

1.14.4 Library Changes
----------------------

Due to time constraints, this document does not exhaustively cover the
very extensive changes to the standard library.  PEP 3108(1) is the
reference for the major changes to the library.  Here’s a capsule
review:

   * Many old modules were removed.  Some, like ‘gopherlib’ (no longer
     used) and ‘md5’ (replaced by *note hashlib: 68.), were already
     deprecated by PEP 4(2).  Others were removed as a result of the
     removal of support for various platforms such as Irix, BeOS and Mac
     OS 9 (see PEP 11(3)).  Some modules were also selected for removal
     in Python 3.0 due to lack of use or because a better replacement
     exists.  See PEP 3108(4) for an exhaustive list.

   * The ‘bsddb3’ package was removed because its presence in the core
     standard library has proved over time to be a particular burden for
     the core developers due to testing instability and Berkeley DB’s
     release schedule.  However, the package is alive and well,
     externally maintained at
     ‘https://www.jcea.es/programacion/pybsddb.htm’.

   * Some modules were renamed because their old name disobeyed PEP
     8(5), or for various other reasons.  Here’s the list:

     Old Name                    New Name
                                 
     --------------------------------------------------------
                                 
     _winreg                     winreg
                                 
                                 
     ConfigParser                configparser
                                 
                                 
     copy_reg                    copyreg
                                 
                                 
     Queue                       queue
                                 
                                 
     SocketServer                socketserver
                                 
                                 
     markupbase                  _markupbase
                                 
                                 
     repr                        reprlib
                                 
                                 
     test.test_support           test.support
                                 

   * A common pattern in Python 2.x is to have one version of a module
     implemented in pure Python, with an optional accelerated version
     implemented as a C extension; for example, *note pickle: a6. and
     ‘cPickle’.  This places the burden of importing the accelerated
     version and falling back on the pure Python version on each user of
     these modules.  In Python 3.0, the accelerated versions are
     considered implementation details of the pure Python versions.
     Users should always import the standard version, which attempts to
     import the accelerated version and falls back to the pure Python
     version.  The ‘pickle’ / ‘cPickle’ pair received this treatment.
     The *note profile: af. module is on the list for 3.1.  The
     ‘StringIO’ module has been turned into a class in the *note io: 7f.
     module.

   * Some related modules have been grouped into packages, and usually
     the submodule names have been simplified.  The resulting new
     packages are:

        * *note dbm: 31. (‘anydbm’, ‘dbhash’, ‘dbm’, ‘dumbdbm’, ‘gdbm’,
          ‘whichdb’).

        * *note html: 6b. (‘HTMLParser’, ‘htmlentitydefs’).

        * *note http: 6e. (‘httplib’, ‘BaseHTTPServer’, ‘CGIHTTPServer’,
          ‘SimpleHTTPServer’, ‘Cookie’, ‘cookielib’).

        * *note tkinter: f0. (all ‘Tkinter’-related modules except *note
          turtle: 101.).  The target audience of ‘turtle’ doesn’t really
          care about ‘tkinter’.  Also note that as of Python 2.6, the
          functionality of ‘turtle’ has been greatly enhanced.

        * *note urllib: 108. (‘urllib’, ‘urllib2’, ‘urlparse’,
          ‘robotparse’).

        * *note xmlrpc: 12d. (‘xmlrpclib’, ‘DocXMLRPCServer’,
          ‘SimpleXMLRPCServer’).

Some other changes to standard library modules, not covered by PEP
3108(6):

   * Killed ‘sets’.  Use the built-in *note set(): 5dc. class.

   * Cleanup of the *note sys: d9. module: removed ‘sys.exitfunc()’,
     ‘sys.exc_clear()’, ‘sys.exc_type’, ‘sys.exc_value’,
     ‘sys.exc_traceback’.  (Note that *note sys.last_type: 4c2. etc.
     remain.)

   * Cleanup of the *note array.array: 1a0. type: the ‘read()’ and
     ‘write()’ methods are gone; use *note fromfile(): 1308. and *note
     tofile(): 1309. instead.  Also, the ‘'c'’ typecode for array is
     gone – use either ‘'b'’ for bytes or ‘'u'’ for Unicode characters.

   * Cleanup of the *note operator: 9f. module: removed
     ‘sequenceIncludes()’ and ‘isCallable()’.

   * Cleanup of the ‘thread’ module: ‘acquire_lock()’ and
     ‘release_lock()’ are gone; use *note acquire(): 69b. and *note
     release(): 130a. instead.

   * Cleanup of the *note random: b8. module: removed the ‘jumpahead()’
     API.

   * The ‘new’ module is gone.

   * The functions ‘os.tmpnam()’, ‘os.tempnam()’ and ‘os.tmpfile()’ have
     been removed in favor of the *note tempfile: e0. module.

   * The *note tokenize: fb. module has been changed to work with bytes.
     The main entry point is now *note tokenize.tokenize(): 4dc, instead
     of generate_tokens.

   * ‘string.letters’ and its friends (‘string.lowercase’ and
     ‘string.uppercase’) are gone.  Use *note string.ascii_letters:
     130b. etc.  instead.  (The reason for the removal is that
     ‘string.letters’ and friends had locale-specific behavior, which is
     a bad idea for such attractively named global “constants”.)

   * Renamed module ‘__builtin__’ to *note builtins: 12. (removing the
     underscores, adding an ‘s’).  The ‘__builtins__’ variable found in
     most global namespaces is unchanged.  To modify a builtin, you
     should use ‘builtins’, not ‘__builtins__’!

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3108/

   (2) https://peps.python.org/pep-0004/

   (3) https://peps.python.org/pep-0011/

   (4) https://peps.python.org/pep-3108/

   (5) https://peps.python.org/pep-0008/

   (6) https://peps.python.org/pep-3108/


File: python.info,  Node: PEP 3101 A New Approach To String Formatting,  Next: Changes To Exceptions,  Prev: Library Changes,  Up: What’s New In Python 3 0

'PEP 3101': A New Approach To String Formatting

   * A new system for built-in string formatting operations replaces the
     ‘%’ string formatting operator.  (However, the ‘%’ operator is
     still supported; it will be deprecated in Python 3.1 and removed
     from the language at some later time.)  Read PEP 3101(1) for the
     full scoop.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3101/


File: python.info,  Node: Changes To Exceptions,  Next: Miscellaneous Other Changes,  Prev: PEP 3101 A New Approach To String Formatting,  Up: What’s New In Python 3 0

1.14.6 Changes To Exceptions
----------------------------

The APIs for raising and catching exception have been cleaned up and new
powerful features added:

   * PEP 352(1): All exceptions must be derived (directly or indirectly)
     from *note BaseException: 5be.  This is the root of the exception
     hierarchy.  This is not new as a recommendation, but the
     'requirement' to inherit from ‘BaseException’ is new.  (Python 2.6
     still allowed classic classes to be raised, and placed no
     restriction on what you can catch.)  As a consequence, string
     exceptions are finally truly and utterly dead.

   * Almost all exceptions should actually derive from *note Exception:
     9e5.; *note BaseException: 5be. should only be used as a base class
     for exceptions that should only be handled at the top level, such
     as *note SystemExit: d69. or *note KeyboardInterrupt: 9dc.  The
     recommended idiom for handling all exceptions except for this
     latter category is to use *note except: 18b. ‘Exception’.

   * ‘StandardError’ was removed.

   * Exceptions no longer behave as sequences.  Use the *note args: 56f.
     attribute instead.

   * PEP 3109(2): Raising exceptions.  You must now use ‘raise
     EXCEPTION(ARGS)’ instead of ‘raise EXCEPTION, ARGS’.  Additionally,
     you can no longer explicitly specify a traceback; instead, if you
     'have' to do this, you can assign directly to the *note
     __traceback__: 130e. attribute (see below).

   * PEP 3110(3): Catching exceptions.  You must now use ‘except
     SOMEEXCEPTION as VARIABLE’ instead of ‘except SOMEEXCEPTION,
     VARIABLE’.  Moreover, the 'variable' is explicitly deleted when the
     *note except: 18b. block is left.

   * PEP 3134(4): Exception chaining.  There are two cases: implicit
     chaining and explicit chaining.  Implicit chaining happens when an
     exception is raised in an *note except: 18b. or *note finally: 9d5.
     handler block.  This usually happens due to a bug in the handler
     block; we call this a 'secondary' exception.  In this case, the
     original exception (that was being handled) is saved as the *note
     __context__: 130f. attribute of the secondary exception.  Explicit
     chaining is invoked with this syntax:

          raise SecondaryException() from primary_exception

     (where 'primary_exception' is any expression that produces an
     exception object, probably an exception that was previously
     caught).  In this case, the primary exception is stored on the
     *note __cause__: 1310. attribute of the secondary exception.  The
     traceback printed when an unhandled exception occurs walks the
     chain of ‘__cause__’ and *note __context__: 130f. attributes and
     prints a separate traceback for each component of the chain, with
     the primary exception at the top.  (Java users may recognize this
     behavior.)

   * PEP 3134(5): Exception objects now store their traceback as the
     *note __traceback__: 130e. attribute.  This means that an exception
     object now contains all the information pertaining to an exception,
     and there are fewer reasons to use *note sys.exc_info(): 68d.
     (though the latter is not removed).

   * A few exception messages are improved when Windows fails to load an
     extension module.  For example, ‘error code 193’ is now ‘%1 is not
     a valid Win32 application’.  Strings now deal with non-English
     locales.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0352/

   (2) https://peps.python.org/pep-3109/

   (3) https://peps.python.org/pep-3110/

   (4) https://peps.python.org/pep-3134/

   (5) https://peps.python.org/pep-3134/


File: python.info,  Node: Miscellaneous Other Changes,  Next: Build and C API Changes<7>,  Prev: Changes To Exceptions,  Up: What’s New In Python 3 0

1.14.7 Miscellaneous Other Changes
----------------------------------

* Menu:

* Operators And Special Methods::
* Builtins::


File: python.info,  Node: Operators And Special Methods,  Next: Builtins,  Up: Miscellaneous Other Changes

1.14.7.1 Operators And Special Methods
......................................

   * ‘!=’ now returns the opposite of ‘==’, unless ‘==’ returns *note
     NotImplemented: 7d6.

   * The concept of “unbound methods” has been removed from the
     language.  When referencing a method as a class attribute, you now
     get a plain function object.

   * ‘__getslice__()’, ‘__setslice__()’ and ‘__delslice__()’ were
     killed.  The syntax ‘a[i:j]’ now translates to
     ‘a.__getitem__(slice(i, j))’ (or *note __setitem__(): 1313. or
     *note __delitem__(): 1314, when used as an assignment or deletion
     target, respectively).

   * PEP 3114(1): the standard *note next(): 7dc. method has been
     renamed to *note __next__(): 1315.

   * The ‘__oct__()’ and ‘__hex__()’ special methods are removed – *note
     oct(): 1316. and *note hex(): 1317. use *note __index__(): 720. now
     to convert the argument to an integer.

   * Removed support for ‘__members__’ and ‘__methods__’.

   * The function attributes named ‘func_X’ have been renamed to use the
     ‘__X__’ form, freeing up these names in the function attribute
     namespace for user-defined attributes.  To wit, ‘func_closure’,
     ‘func_code’, ‘func_defaults’, ‘func_dict’, ‘func_doc’,
     ‘func_globals’, ‘func_name’ were renamed to *note __closure__:
     1318, *note __code__: 29a, *note __defaults__: 1319, *note
     __dict__: 131a, *note __doc__: 121e, *note __globals__: 131b, *note
     __name__: 131c, respectively.

   * ‘__nonzero__()’ is now *note __bool__(): 131d.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3114/


File: python.info,  Node: Builtins,  Prev: Operators And Special Methods,  Up: Miscellaneous Other Changes

1.14.7.2 Builtins
.................

   * PEP 3135(1): New *note super(): 4de.  You can now invoke ‘super()’
     without arguments and (assuming this is in a regular instance
     method defined inside a *note class: 131f. statement) the right
     class and instance will automatically be chosen.  With arguments,
     the behavior of ‘super()’ is unchanged.

   * PEP 3111(2): ‘raw_input()’ was renamed to *note input(): 1320.
     That is, the new ‘input()’ function reads a line from *note
     sys.stdin: 540. and returns it with the trailing newline stripped.
     It raises *note EOFError: 1321. if the input is terminated
     prematurely.  To get the old behavior of ‘input()’, use
     ‘eval(input())’.

   * A new built-in function *note next(): 7dc. was added to call the
     *note __next__(): 1315. method on an object.

   * The *note round(): 1322. function rounding strategy and return type
     have changed.  Exact halfway cases are now rounded to the nearest
     even result instead of away from zero.  (For example, ‘round(2.5)’
     now returns ‘2’ rather than ‘3’.)  ‘round(x[, n])’ now delegates to
     ‘x.__round__([n])’ instead of always returning a float.  It
     generally returns an integer when called with a single argument and
     a value of the same type as ‘x’ when called with two arguments.

   * Moved ‘intern()’ to *note sys.intern(): 1323.

   * Removed: ‘apply()’.  Instead of ‘apply(f, args)’ use ‘f(*args)’.

   * Removed *note callable(): 120b.  Instead of ‘callable(f)’ you can
     use ‘isinstance(f, collections.Callable)’.  The
     ‘operator.isCallable()’ function is also gone.

   * Removed ‘coerce()’.  This function no longer serves a purpose now
     that classic classes are gone.

   * Removed ‘execfile()’.  Instead of ‘execfile(fn)’ use
     ‘exec(open(fn).read())’.

   * Removed the ‘file’ type.  Use *note open(): 51f.  There are now
     several different kinds of streams that open can return in the
     *note io: 7f. module.

   * Removed ‘reduce()’.  Use *note functools.reduce(): 1324. if you
     really need it; however, 99 percent of the time an explicit *note
     for: 2f2. loop is more readable.

   * Removed ‘reload()’.  Use ‘imp.reload()’.

   * Removed.  ‘dict.has_key()’ – use the *note in: 2f4. operator
     instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3135/

   (2) https://peps.python.org/pep-3111/


File: python.info,  Node: Build and C API Changes<7>,  Next: Performance,  Prev: Miscellaneous Other Changes,  Up: What’s New In Python 3 0

1.14.8 Build and C API Changes
------------------------------

Due to time constraints, here is a 'very' incomplete list of changes to
the C API.

   * Support for several platforms was dropped, including but not
     limited to Mac OS 9, BeOS, RISCOS, Irix, and Tru64.

   * PEP 3118(1): New Buffer API.

   * PEP 3121(2): Extension Module Initialization & Finalization.

   * PEP 3123(3): Making *note PyObject_HEAD: 1326. conform to standard
     C.

   * No more C API support for restricted execution.

   * ‘PyNumber_Coerce()’, ‘PyNumber_CoerceEx()’, ‘PyMember_Get()’, and
     ‘PyMember_Set()’ C APIs are removed.

   * New C API *note PyImport_ImportModuleNoBlock(): 3c0, works like
     *note PyImport_ImportModule(): 3c1. but won’t block on the import
     lock (returning an error instead).

   * Renamed the boolean conversion C-level slot and method:
     ‘nb_nonzero’ is now ‘nb_bool’.

   * Removed ‘METH_OLDARGS’ and ‘WITH_CYCLE_GC’ from the C API.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/

   (2) https://peps.python.org/pep-3121/

   (3) https://peps.python.org/pep-3123/


File: python.info,  Node: Performance,  Next: Porting To Python 3 0,  Prev: Build and C API Changes<7>,  Up: What’s New In Python 3 0

1.14.9 Performance
------------------

The net result of the 3.0 generalizations is that Python 3.0 runs the
pystone benchmark around 10% slower than Python 2.5.  Most likely the
biggest cause is the removal of special-casing for small integers.
There’s room for improvement, but it will happen after 3.0 is released!


File: python.info,  Node: Porting To Python 3 0,  Prev: Performance,  Up: What’s New In Python 3 0

1.14.10 Porting To Python 3.0
-----------------------------

For porting existing Python 2.5 or 2.6 source code to Python 3.0, the
best strategy is the following:

  0. (Prerequisite:) Start with excellent test coverage.

  1. Port to Python 2.6.  This should be no more work than the average
     port from Python 2.x to Python 2.(x+1).  Make sure all your tests
     pass.

  2. (Still using 2.6:) Turn on the ‘-3’ command line switch.  This
     enables warnings about features that will be removed (or change) in
     3.0.  Run your test suite again, and fix code that you get warnings
     about until there are no warnings left, and all your tests still
     pass.

  3. Run the ‘2to3’ source-to-source translator over your source code
     tree.  Run the result of the translation under Python 3.0.
     Manually fix up any remaining issues, fixing problems until all
     tests pass again.

It is not recommended to try to write source code that runs unchanged
under both Python 2.6 and 3.0; you’d have to use a very contorted coding
style, e.g.  avoiding ‘print’ statements, metaclasses, and much more.
If you are maintaining a library that needs to support both Python 2.6
and Python 3.0, the best approach is to modify step 3 above by editing
the 2.6 version of the source code and running the ‘2to3’ translator
again, rather than editing the 3.0 version of the source code.

For porting C extensions to Python 3.0, please see *note Porting
Extension Modules to Python 3: 1329.


File: python.info,  Node: What’s New in Python 2 7,  Next: What’s New in Python 2 6,  Prev: What’s New In Python 3 0,  Up: What’s New in Python

1.15 What’s New in Python 2.7
=============================


Author: A.M. Kuchling (amk at amk.ca)

This article explains the new features in Python 2.7.  Python 2.7 was
released on July 3, 2010.

Numeric handling has been improved in many ways, for both floating-point
numbers and for the *note Decimal: 29d. class.  There are some useful
additions to the standard library, such as a greatly enhanced *note
unittest: 106. module, the *note argparse: 6. module for parsing
command-line options, convenient *note OrderedDict: 5de. and *note
Counter: 10d5. classes in the *note collections: 1d. module, and many
other improvements.

Python 2.7 is planned to be the last of the 2.x releases, so we worked
on making it a good release for the long term.  To help with porting to
Python 3, several new features from the Python 3.x series have been
included in 2.7.

This article doesn’t attempt to provide a complete specification of the
new features, but instead provides a convenient overview.  For full
details, you should refer to the documentation for Python 2.7 at
‘https://docs.python.org’.  If you want to understand the rationale for
the design and implementation, refer to the PEP for a particular new
feature or the issue on ‘https://bugs.python.org’ in which a change was
discussed.  Whenever possible, “What’s New in Python” links to the
bug/patch item for each change.

* Menu:

* The Future for Python 2.x: The Future for Python 2 x.
* Changes to the Handling of Deprecation Warnings::
* Python 3.1 Features: Python 3 1 Features.
* PEP 372; Adding an Ordered Dictionary to collections: PEP 372 Adding an Ordered Dictionary to collections.
* PEP 378; Format Specifier for Thousands Separator: PEP 378 Format Specifier for Thousands Separator<2>.
* PEP 389; The argparse Module for Parsing Command Lines: PEP 389 The argparse Module for Parsing Command Lines.
* PEP 391; Dictionary-Based Configuration For Logging: PEP 391 Dictionary-Based Configuration For Logging.
* PEP 3106; Dictionary Views: PEP 3106 Dictionary Views.
* PEP 3137; The memoryview Object: PEP 3137 The memoryview Object.
* Other Language Changes: Other Language Changes<14>.
* New and Improved Modules::
* Build and C API Changes: Build and C API Changes<8>.
* Other Changes and Fixes::
* Porting to Python 2.7: Porting to Python 2 7.
* New Features Added to Python 2.7 Maintenance Releases: New Features Added to Python 2 7 Maintenance Releases.
* Acknowledgements::


File: python.info,  Node: The Future for Python 2 x,  Next: Changes to the Handling of Deprecation Warnings,  Up: What’s New in Python 2 7

1.15.1 The Future for Python 2.x
--------------------------------

Python 2.7 is the last major release in the 2.x series, as the Python
maintainers have shifted the focus of their new feature development
efforts to the Python 3.x series.  This means that while Python 2
continues to receive bug fixes, and to be updated to build correctly on
new hardware and versions of supported operated systems, there will be
no new full feature releases for the language or standard library.

However, while there is a large common subset between Python 2.7 and
Python 3, and many of the changes involved in migrating to that common
subset, or directly to Python 3, can be safely automated, some other
changes (notably those associated with Unicode handling) may require
careful consideration, and preferably robust automated regression test
suites, to migrate effectively.

This means that Python 2.7 will remain in place for a long time,
providing a stable and supported base platform for production systems
that have not yet been ported to Python 3.  The full expected lifecycle
of the Python 2.7 series is detailed in PEP 373(1).

Some key consequences of the long-term significance of 2.7 are:

   * As noted above, the 2.7 release has a much longer period of
     maintenance when compared to earlier 2.x versions.  Python 2.7 is
     currently expected to remain supported by the core development team
     (receiving security updates and other bug fixes) until at least
     2020 (10 years after its initial release, compared to the more
     typical support period of 18–24 months).

   * As the Python 2.7 standard library ages, making effective use of
     the Python Package Index (either directly or via a redistributor)
     becomes more important for Python 2 users.  In addition to a wide
     variety of third party packages for various tasks, the available
     packages include backports of new modules and features from the
     Python 3 standard library that are compatible with Python 2, as
     well as various tools and libraries that can make it easier to
     migrate to Python 3.  The Python Packaging User Guide(2) provides
     guidance on downloading and installing software from the Python
     Package Index.

   * While the preferred approach to enhancing Python 2 is now the
     publication of new packages on the Python Package Index, this
     approach doesn’t necessarily work in all cases, especially those
     related to network security.  In exceptional cases that cannot be
     handled adequately by publishing new or updated packages on PyPI,
     the Python Enhancement Proposal process may be used to make the
     case for adding new features directly to the Python 2 standard
     library.  Any such additions, and the maintenance releases where
     they were added, will be noted in the *note New Features Added to
     Python 2.7 Maintenance Releases: 132f. section below.

For projects wishing to migrate from Python 2 to Python 3, or for
library and framework developers wishing to support users on both Python
2 and Python 3, there are a variety of tools and guides available to
help decide on a suitable approach and manage some of the technical
details involved.  The recommended starting point is the pyporting-howto
HOWTO guide.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0373/

   (2) https://packaging.python.org


File: python.info,  Node: Changes to the Handling of Deprecation Warnings,  Next: Python 3 1 Features,  Prev: The Future for Python 2 x,  Up: What’s New in Python 2 7

1.15.2 Changes to the Handling of Deprecation Warnings
------------------------------------------------------

For Python 2.7, a policy decision was made to silence warnings only of
interest to developers by default.  *note DeprecationWarning: 1a5. and
its descendants are now ignored unless otherwise requested, preventing
users from seeing warnings triggered by an application.  This change was
also made in the branch that became Python 3.2.  (Discussed on
stdlib-sig and carried out in bpo-7319(1).)

In previous releases, *note DeprecationWarning: 1a5. messages were
enabled by default, providing Python developers with a clear indication
of where their code may break in a future major version of Python.

However, there are increasingly many users of Python-based applications
who are not directly involved in the development of those applications.
*note DeprecationWarning: 1a5. messages are irrelevant to such users,
making them worry about an application that’s actually working correctly
and burdening application developers with responding to these concerns.

You can re-enable display of *note DeprecationWarning: 1a5. messages by
running Python with the *note -Wdefault: 8d0. (short form: ‘-Wd’)
switch, or by setting the *note PYTHONWARNINGS: bc8. environment
variable to ‘"default"’ (or ‘"d"’) before running Python.  Python code
can also re-enable them by calling ‘warnings.simplefilter('default')’.

The ‘unittest’ module also automatically reenables deprecation warnings
when running tests.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7319


File: python.info,  Node: Python 3 1 Features,  Next: PEP 372 Adding an Ordered Dictionary to collections,  Prev: Changes to the Handling of Deprecation Warnings,  Up: What’s New in Python 2 7

1.15.3 Python 3.1 Features
--------------------------

Much as Python 2.6 incorporated features from Python 3.0, version 2.7
incorporates some of the new features in Python 3.1.  The 2.x series
continues to provide tools for migrating to the 3.x series.

A partial list of 3.1 features that were backported to 2.7:

   * The syntax for set literals (‘{1,2,3}’ is a mutable set).

   * Dictionary and set comprehensions (‘{i: i*2 for i in range(3)}’).

   * Multiple context managers in a single *note with: 5d5. statement.

   * A new version of the *note io: 7f. library, rewritten in C for
     performance.

   * The ordered-dictionary type described in *note PEP 372; Adding an
     Ordered Dictionary to collections: 1332.

   * The new ‘","’ format specifier described in *note PEP 378; Format
     Specifier for Thousands Separator: 1333.

   * The *note memoryview: 2eb. object.

   * A small subset of the *note importlib: 77. module, *note described
     below: 1334.

   * The *note repr(): 803. of a float ‘x’ is shorter in many cases:
     it’s now based on the shortest decimal string that’s guaranteed to
     round back to ‘x’.  As in previous versions of Python, it’s
     guaranteed that ‘float(repr(x))’ recovers ‘x’.

   * Float-to-string and string-to-float conversions are correctly
     rounded.  The *note round(): 1322. function is also now correctly
     rounded.

   * The *note PyCapsule: 12b9. type, used to provide a C API for
     extension modules.

   * The *note PyLong_AsLongAndOverflow(): 12ad. C API function.

Other new Python3-mode warnings include:

   * ‘operator.isCallable()’ and ‘operator.sequenceIncludes()’, which
     are not supported in 3.x, now trigger warnings.

   * The ‘-3’ switch now automatically enables the ‘-Qwarn’ switch that
     causes warnings about using classic division with integers and long
     integers.


File: python.info,  Node: PEP 372 Adding an Ordered Dictionary to collections,  Next: PEP 378 Format Specifier for Thousands Separator<2>,  Prev: Python 3 1 Features,  Up: What’s New in Python 2 7

1.15.4 PEP 372: Adding an Ordered Dictionary to collections
-----------------------------------------------------------

Regular Python dictionaries iterate over key/value pairs in arbitrary
order.  Over the years, a number of authors have written alternative
implementations that remember the order that the keys were originally
inserted.  Based on the experiences from those implementations, 2.7
introduces a new *note OrderedDict: 5de. class in the *note collections:
1d. module.

The *note OrderedDict: 5de. API provides the same interface as regular
dictionaries but iterates over keys and values in a guaranteed order
depending on when a key was first inserted:

     >>> from collections import OrderedDict
     >>> d = OrderedDict([('first', 1),
     ...                  ('second', 2),
     ...                  ('third', 3)])
     >>> d.items()
     [('first', 1), ('second', 2), ('third', 3)]

If a new entry overwrites an existing entry, the original insertion
position is left unchanged:

     >>> d['second'] = 4
     >>> d.items()
     [('first', 1), ('second', 4), ('third', 3)]

Deleting an entry and reinserting it will move it to the end:

     >>> del d['second']
     >>> d['second'] = 5
     >>> d.items()
     [('first', 1), ('third', 3), ('second', 5)]

The *note popitem(): 1336. method has an optional 'last' argument that
defaults to ‘True’.  If 'last' is true, the most recently added key is
returned and removed; if it’s false, the oldest key is selected:

     >>> od = OrderedDict([(x,0) for x in range(20)])
     >>> od.popitem()
     (19, 0)
     >>> od.popitem()
     (18, 0)
     >>> od.popitem(last=False)
     (0, 0)
     >>> od.popitem(last=False)
     (1, 0)

Comparing two ordered dictionaries checks both the keys and values, and
requires that the insertion order was the same:

     >>> od1 = OrderedDict([('first', 1),
     ...                    ('second', 2),
     ...                    ('third', 3)])
     >>> od2 = OrderedDict([('third', 3),
     ...                    ('first', 1),
     ...                    ('second', 2)])
     >>> od1 == od2
     False
     >>> # Move 'third' key to the end
     >>> del od2['third']; od2['third'] = 3
     >>> od1 == od2
     True

Comparing an *note OrderedDict: 5de. with a regular dictionary ignores
the insertion order and just compares the keys and values.

How does the *note OrderedDict: 5de. work?  It maintains a doubly linked
list of keys, appending new keys to the list as they’re inserted.  A
secondary dictionary maps keys to their corresponding list node, so
deletion doesn’t have to traverse the entire linked list and therefore
remains 'O'(1).

The standard library now supports use of ordered dictionaries in several
modules.

   * The *note ConfigParser: 22. module uses them by default, meaning
     that configuration files can now be read, modified, and then
     written back in their original order.

   * The *note _asdict(): 9ec. method for *note
     collections.namedtuple(): 1ca. now returns an ordered dictionary
     with the values appearing in the same order as the underlying tuple
     indices.

   * The *note json: 82. module’s *note JSONDecoder: d70. class
     constructor was extended with an 'object_pairs_hook' parameter to
     allow ‘OrderedDict’ instances to be built by the decoder.  Support
     was also added for third-party tools like PyYAML(1).

See also
........

PEP 372(2) - Adding an ordered dictionary to collections

     PEP written by Armin Ronacher and Raymond Hettinger; implemented by
     Raymond Hettinger.

   ---------- Footnotes ----------

   (1) https://pyyaml.org/

   (2) https://peps.python.org/pep-0372/


File: python.info,  Node: PEP 378 Format Specifier for Thousands Separator<2>,  Next: PEP 389 The argparse Module for Parsing Command Lines,  Prev: PEP 372 Adding an Ordered Dictionary to collections,  Up: What’s New in Python 2 7

1.15.5 PEP 378: Format Specifier for Thousands Separator
--------------------------------------------------------

To make program output more readable, it can be useful to add separators
to large numbers, rendering them as 18,446,744,073,709,551,616 instead
of 18446744073709551616.

The fully general solution for doing this is the *note locale: 86.
module, which can use different separators (“,” in North America, “.” in
Europe) and different grouping sizes, but ‘locale’ is complicated to use
and unsuitable for multi-threaded applications where different threads
are producing output for different locales.

Therefore, a simple comma-grouping mechanism has been added to the
mini-language used by the *note str.format(): 624. method.  When
formatting a floating-point number, simply include a comma between the
width and the precision:

     >>> '{:20,.2f}'.format(18446744073709551616.0)
     '18,446,744,073,709,551,616.00'

When formatting an integer, include the comma after the width:

     >>> '{:20,d}'.format(18446744073709551616)
     '18,446,744,073,709,551,616'

This mechanism is not adaptable at all; commas are always used as the
separator and the grouping is always into three-digit groups.  The
comma-formatting mechanism isn’t as general as the *note locale: 86.
module, but it’s easier to use.

See also
........

PEP 378(1) - Format Specifier for Thousands Separator

     PEP written by Raymond Hettinger; implemented by Eric Smith.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0378/


File: python.info,  Node: PEP 389 The argparse Module for Parsing Command Lines,  Next: PEP 391 Dictionary-Based Configuration For Logging,  Prev: PEP 378 Format Specifier for Thousands Separator<2>,  Up: What’s New in Python 2 7

1.15.6 PEP 389: The argparse Module for Parsing Command Lines
-------------------------------------------------------------

The *note argparse: 6. module for parsing command-line arguments was
added as a more powerful replacement for the *note optparse: a0. module.

This means Python now supports three different modules for parsing
command-line arguments: *note getopt: 61, *note optparse: a0, and *note
argparse: 6.  The ‘getopt’ module closely resembles the C library’s
‘getopt()’ function, so it remains useful if you’re writing a Python
prototype that will eventually be rewritten in C. ‘optparse’ becomes
redundant, but there are no plans to remove it because there are many
scripts still using it, and there’s no automated way to update these
scripts.  (Making the ‘argparse’ API consistent with ‘optparse’’s
interface was discussed but rejected as too messy and difficult.)

In short, if you’re writing a new script and don’t need to worry about
compatibility with earlier versions of Python, use *note argparse: 6.
instead of *note optparse: a0.

Here’s an example:

     import argparse

     parser = argparse.ArgumentParser(description='Command-line example.')

     # Add optional switches
     parser.add_argument('-v', action='store_true', dest='is_verbose',
                         help='produce verbose output')
     parser.add_argument('-o', action='store', dest='output',
                         metavar='FILE',
                         help='direct output to FILE instead of stdout')
     parser.add_argument('-C', action='store', type=int, dest='context',
                         metavar='NUM', default=0,
                         help='display NUM lines of added context')

     # Allow any number of additional arguments.
     parser.add_argument(nargs='*', action='store', dest='inputs',
                         help='input filenames (default is stdin)')

     args = parser.parse_args()
     print args.__dict__

Unless you override it, ‘-h’ and ‘--help’ switches are automatically
added, and produce neatly formatted output:

     -> ./python.exe argparse-example.py --help
     usage: argparse-example.py [-h] [-v] [-o FILE] [-C NUM] [inputs [inputs ...]]

     Command-line example.

     positional arguments:
       inputs      input filenames (default is stdin)

     optional arguments:
       -h, --help  show this help message and exit
       -v          produce verbose output
       -o FILE     direct output to FILE instead of stdout
       -C NUM      display NUM lines of added context

As with *note optparse: a0, the command-line switches and arguments are
returned as an object with attributes named by the 'dest' parameters:

     -> ./python.exe argparse-example.py -v
     {'output': None,
      'is_verbose': True,
      'context': 0,
      'inputs': []}

     -> ./python.exe argparse-example.py -v -o /tmp/output -C 4 file1 file2
     {'output': '/tmp/output',
      'is_verbose': True,
      'context': 4,
      'inputs': ['file1', 'file2']}

*note argparse: 6. has much fancier validation than *note optparse: a0.;
you can specify an exact number of arguments as an integer, 0 or more
arguments by passing ‘'*'’, 1 or more by passing ‘'+'’, or an optional
argument with ‘'?'’.  A top-level parser can contain sub-parsers to
define subcommands that have different sets of switches, as in ‘svn
commit’, ‘svn checkout’, etc.  You can specify an argument’s type as
*note FileType: f52, which will automatically open files for you and
understands that ‘'-'’ means standard input or output.

See also
........

*note argparse: 6. documentation

     The documentation page of the argparse module.

*note Migrating optparse code to argparse: 11f2.

     Part of the Python documentation, describing how to convert code
     that uses *note optparse: a0.

PEP 389(1) - argparse - New Command Line Parsing Module

     PEP written and implemented by Steven Bethard.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0389/


File: python.info,  Node: PEP 391 Dictionary-Based Configuration For Logging,  Next: PEP 3106 Dictionary Views,  Prev: PEP 389 The argparse Module for Parsing Command Lines,  Up: What’s New in Python 2 7

1.15.7 PEP 391: Dictionary-Based Configuration For Logging
----------------------------------------------------------

The *note logging: 87. module is very flexible; applications can define
a tree of logging subsystems, and each logger in this tree can filter
out certain messages, format them differently, and direct messages to a
varying number of handlers.

All this flexibility can require a lot of configuration.  You can write
Python statements to create objects and set their properties, but a
complex set-up requires verbose but boring code.  *note logging: 87.
also supports a *note fileConfig(): b6c. function that parses a file,
but the file format doesn’t support configuring filters, and it’s
messier to generate programmatically.

Python 2.7 adds a *note dictConfig(): 11f4. function that uses a
dictionary to configure logging.  There are many ways to produce a
dictionary from different sources: construct one with code; parse a file
containing JSON; or use a YAML parsing library if one is installed.  For
more information see *note Configuration functions: 133a.

The following example configures two loggers, the root logger and a
logger named “network”.  Messages sent to the root logger will be sent
to the system log using the syslog protocol, and messages to the
“network” logger will be written to a ‘network.log’ file that will be
rotated once the log reaches 1MB.

     import logging
     import logging.config

     configdict = {
      'version': 1,    # Configuration schema in use; must be 1 for now
      'formatters': {
          'standard': {
              'format': ('%(asctime)s %(name)-15s '
                         '%(levelname)-8s %(message)s')}},

      'handlers': {'netlog': {'backupCount': 10,
                          'class': 'logging.handlers.RotatingFileHandler',
                          'filename': '/logs/network.log',
                          'formatter': 'standard',
                          'level': 'INFO',
                          'maxBytes': 1000000},
                   'syslog': {'class': 'logging.handlers.SysLogHandler',
                              'formatter': 'standard',
                              'level': 'ERROR'}},

      # Specify all the subordinate loggers
      'loggers': {
                  'network': {
                              'handlers': ['netlog']
                  }
      },
      # Specify properties of the root logger
      'root': {
               'handlers': ['syslog']
      },
     }

     # Set up configuration
     logging.config.dictConfig(configdict)

     # As an example, log two error messages
     logger = logging.getLogger('/')
     logger.error('Database not found')

     netlogger = logging.getLogger('network')
     netlogger.error('Connection failed')

Three smaller enhancements to the *note logging: 87. module, all
implemented by Vinay Sajip, are:

   * The *note SysLogHandler: 65f. class now supports syslogging over
     TCP. The constructor has a 'socktype' parameter giving the type of
     socket to use, either *note socket.SOCK_DGRAM: 133b. for UDP or
     *note socket.SOCK_STREAM: 133c. for TCP. The default protocol
     remains UDP.

   * *note Logger: b6a. instances gained a *note getChild(): 133d.
     method that retrieves a descendant logger using a relative path.
     For example, once you retrieve a logger by doing ‘log =
     getLogger('app')’, calling ‘log.getChild('network.listen')’ is
     equivalent to ‘getLogger('app.network.listen')’.

   * The *note LoggerAdapter: 133e. class gained an *note
     isEnabledFor(): 133f. method that takes a 'level' and returns
     whether the underlying logger would process a message of that level
     of importance.

See also
........

PEP 391(1) - Dictionary-Based Configuration For Logging

     PEP written and implemented by Vinay Sajip.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0391/


File: python.info,  Node: PEP 3106 Dictionary Views,  Next: PEP 3137 The memoryview Object,  Prev: PEP 391 Dictionary-Based Configuration For Logging,  Up: What’s New in Python 2 7

1.15.8 PEP 3106: Dictionary Views
---------------------------------

The dictionary methods *note keys(): 7d1, *note values(): 7d2, and *note
items(): 7d3. are different in Python 3.x.  They return an object called
a 'view' instead of a fully materialized list.

It’s not possible to change the return values of *note keys(): 7d1,
*note values(): 7d2, and *note items(): 7d3. in Python 2.7 because too
much code would break.  Instead the 3.x versions were added under the
new names ‘viewkeys()’, ‘viewvalues()’, and ‘viewitems()’.

     >>> d = dict((i*10, chr(65+i)) for i in range(26))
     >>> d
     {0: 'A', 130: 'N', 10: 'B', 140: 'O', 20: ..., 250: 'Z'}
     >>> d.viewkeys()
     dict_keys([0, 130, 10, 140, 20, 150, 30, ..., 250])

Views can be iterated over, but the key and item views also behave like
sets.  The ‘&’ operator performs intersection, and ‘|’ performs a union:

     >>> d1 = dict((i*10, chr(65+i)) for i in range(26))
     >>> d2 = dict((i**.5, i) for i in range(1000))
     >>> d1.viewkeys() & d2.viewkeys()
     set([0.0, 10.0, 20.0, 30.0])
     >>> d1.viewkeys() | range(0, 30)
     set([0, 1, 130, 3, 4, 5, 6, ..., 120, 250])

The view keeps track of the dictionary and its contents change as the
dictionary is modified:

     >>> vk = d.viewkeys()
     >>> vk
     dict_keys([0, 130, 10, ..., 250])
     >>> d[260] = '&'
     >>> vk
     dict_keys([0, 130, 260, 10, ..., 250])

However, note that you can’t add or remove keys while you’re iterating
over the view:

     >>> for k in vk:
     ...     d[k*2] = k
     ...
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     RuntimeError: dictionary changed size during iteration

You can use the view methods in Python 2.x code, and the 2to3 converter
will change them to the standard *note keys(): 7d1, *note values(): 7d2,
and *note items(): 7d3. methods.

See also
........

PEP 3106(1) - Revamping dict.keys(), .values() and .items()

     PEP written by Guido van Rossum.  Backported to 2.7 by Alexandre
     Vassalotti; bpo-1967(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3106/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1967


File: python.info,  Node: PEP 3137 The memoryview Object,  Next: Other Language Changes<14>,  Prev: PEP 3106 Dictionary Views,  Up: What’s New in Python 2 7

1.15.9 PEP 3137: The memoryview Object
--------------------------------------

The *note memoryview: 2eb. object provides a view of another object’s
memory content that matches the *note bytes: 1c2. type’s interface.

     >>> import string
     >>> m = memoryview(string.letters)
     >>> m
     <memory at 0x37f850>
     >>> len(m)           # Returns length of underlying object
     52
     >>> m[0], m[25], m[26]   # Indexing returns one byte
     ('a', 'z', 'A')
     >>> m2 = m[0:26]         # Slicing returns another memoryview
     >>> m2
     <memory at 0x37f080>

The content of the view can be converted to a string of bytes or a list
of integers:

     >>> m2.tobytes()
     'abcdefghijklmnopqrstuvwxyz'
     >>> m2.tolist()
     [97, 98, 99, 100, 101, 102, 103, ... 121, 122]
     >>>

*note memoryview: 2eb. objects allow modifying the underlying object if
it’s a mutable object.

     >>> m2[0] = 75
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: cannot modify read-only memory
     >>> b = bytearray(string.letters)  # Creating a mutable object
     >>> b
     bytearray(b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
     >>> mb = memoryview(b)
     >>> mb[0] = '*'         # Assign to view, changing the bytearray.
     >>> b[0:5]              # The bytearray has been changed.
     bytearray(b'*bcde')
     >>>

See also
........

PEP 3137(1) - Immutable Bytes and Mutable Buffer

     PEP written by Guido van Rossum.  Implemented by Travis Oliphant,
     Antoine Pitrou and others.  Backported to 2.7 by Antoine Pitrou;
     bpo-2396(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3137/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2396


File: python.info,  Node: Other Language Changes<14>,  Next: New and Improved Modules,  Prev: PEP 3137 The memoryview Object,  Up: What’s New in Python 2 7

1.15.10 Other Language Changes
------------------------------

Some smaller changes made to the core Python language are:

   * The syntax for set literals has been backported from Python 3.x.
     Curly brackets are used to surround the contents of the resulting
     mutable set; set literals are distinguished from dictionaries by
     not containing colons and values.  ‘{}’ continues to represent an
     empty dictionary; use ‘set()’ for an empty set.

          >>> {1, 2, 3, 4, 5}
          set([1, 2, 3, 4, 5])
          >>> set() # empty set
          set([])
          >>> {}    # empty dict
          {}

     Backported by Alexandre Vassalotti; bpo-2335(1).

   * Dictionary and set comprehensions are another feature backported
     from 3.x, generalizing list/generator comprehensions to use the
     literal syntax for sets and dictionaries.

          >>> {x: x*x for x in range(6)}
          {0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
          >>> {('a'*x) for x in range(6)}
          set(['', 'a', 'aa', 'aaa', 'aaaa', 'aaaaa'])

     Backported by Alexandre Vassalotti; bpo-2333(2).

   * The *note with: 5d5. statement can now use multiple context
     managers in one statement.  Context managers are processed from
     left to right and each one is treated as beginning a new ‘with’
     statement.  This means that:

          with A() as a, B() as b:
              ... suite of statements ...

     is equivalent to:

          with A() as a:
              with B() as b:
                  ... suite of statements ...

     The ‘contextlib.nested()’ function provides a very similar
     function, so it’s no longer necessary and has been deprecated.

     (Proposed in ‘https://codereview.appspot.com/53094’; implemented by
     Georg Brandl.)

   * Conversions between floating-point numbers and strings are now
     correctly rounded on most platforms.  These conversions occur in
     many different places: *note str(): 44f. on floats and complex
     numbers; the *note float: 2f7. and *note complex: 2f8.
     constructors; numeric formatting; serializing and deserializing
     floats and complex numbers using the *note marshal: 8d, *note
     pickle: a6. and *note json: 82. modules; parsing of float and
     imaginary literals in Python code; and *note Decimal: 29d.-to-float
     conversion.

     Related to this, the *note repr(): 803. of a floating-point number
     'x' now returns a result based on the shortest decimal string
     that’s guaranteed to round back to 'x' under correct rounding (with
     round-half-to-even rounding mode).  Previously it gave a string
     based on rounding x to 17 decimal digits.

     The rounding library responsible for this improvement works on
     Windows and on Unix platforms using the gcc, icc, or suncc
     compilers.  There may be a small number of platforms where correct
     operation of this code cannot be guaranteed, so the code is not
     used on such systems.  You can find out which code is being used by
     checking *note sys.float_repr_style: 1343, which will be ‘short’ if
     the new code is in use and ‘legacy’ if it isn’t.

     Implemented by Eric Smith and Mark Dickinson, using David Gay’s
     ‘dtoa.c’ library; bpo-7117(3).

   * Conversions from long integers and regular integers to floating
     point now round differently, returning the floating-point number
     closest to the number.  This doesn’t matter for small integers that
     can be converted exactly, but for large numbers that will
     unavoidably lose precision, Python 2.7 now approximates more
     closely.  For example, Python 2.6 computed the following:

          >>> n = 295147905179352891391
          >>> float(n)
          2.9514790517935283e+20
          >>> n - long(float(n))
          65535L

     Python 2.7’s floating-point result is larger, but much closer to
     the true value:

          >>> n = 295147905179352891391
          >>> float(n)
          2.9514790517935289e+20
          >>> n - long(float(n))
          -1L

     (Implemented by Mark Dickinson; bpo-3166(4).)

     Integer division is also more accurate in its rounding behaviours.
     (Also implemented by Mark Dickinson; bpo-1811(5).)

   * Implicit coercion for complex numbers has been removed; the
     interpreter will no longer ever attempt to call a ‘__coerce__()’
     method on complex objects.  (Removed by Meador Inge and Mark
     Dickinson; bpo-5211(6).)

   * The *note str.format(): 624. method now supports automatic
     numbering of the replacement fields.  This makes using
     ‘str.format()’ more closely resemble using ‘%s’ formatting:

          >>> '{}:{}:{}'.format(2009, 04, 'Sunday')
          '2009:4:Sunday'
          >>> '{}:{}:{day}'.format(2009, 4, day='Sunday')
          '2009:4:Sunday'

     The auto-numbering takes the fields from left to right, so the
     first ‘{...}’ specifier will use the first argument to *note
     str.format(): 624, the next specifier will use the next argument,
     and so on.  You can’t mix auto-numbering and explicit numbering –
     either number all of your specifier fields or none of them – but
     you can mix auto-numbering and named fields, as in the second
     example above.  (Contributed by Eric Smith; bpo-5237(7).)

     Complex numbers now correctly support usage with *note format():
     622, and default to being right-aligned.  Specifying a precision or
     comma-separation applies to both the real and imaginary parts of
     the number, but a specified field width and alignment is applied to
     the whole of the resulting ‘1.5+3j’ output.  (Contributed by Eric
     Smith; bpo-1588(8) and bpo-7988(9).)

     The ‘F’ format code now always formats its output using uppercase
     characters, so it will now produce ‘INF’ and ‘NAN’.  (Contributed
     by Eric Smith; bpo-3382(10).)

     A low-level change: the *note object.__format__(): 621. method now
     triggers a *note PendingDeprecationWarning: 8d1. if it’s passed a
     format string, because the ‘__format__()’ method for *note object:
     a9b. converts the object to a string representation and formats
     that.  Previously the method silently applied the format string to
     the string representation, but that could hide mistakes in Python
     code.  If you’re supplying formatting information such as an
     alignment or precision, presumably you’re expecting the formatting
     to be applied in some object-specific way.  (Fixed by Eric Smith;
     bpo-7994(11).)

   * The *note int(): 257. and ‘long()’ types gained a ‘bit_length’
     method that returns the number of bits necessary to represent its
     argument in binary:

          >>> n = 37
          >>> bin(n)
          '0b100101'
          >>> n.bit_length()
          6
          >>> n = 2**123-1
          >>> n.bit_length()
          123
          >>> (n+1).bit_length()
          124

     (Contributed by Fredrik Johansson and Victor Stinner;
     bpo-3439(12).)

   * The *note import: 5e5. statement will no longer try an absolute
     import if a relative import (e.g.  ‘from .os import sep’) fails.
     This fixes a bug, but could possibly break certain ‘import’
     statements that were only working by accident.  (Fixed by Meador
     Inge; bpo-7902(13).)

   * It’s now possible for a subclass of the built-in ‘unicode’ type to
     override the ‘__unicode__()’ method.  (Implemented by Victor
     Stinner; bpo-1583863(14).)

   * The *note bytearray: 2ea. type’s *note translate(): 1344. method
     now accepts ‘None’ as its first argument.  (Fixed by Georg Brandl;
     bpo-4759(15).)

   * When using *note @classmethod: 166. and *note @staticmethod: 419.
     to wrap methods as class or static methods, the wrapper object now
     exposes the wrapped function as their *note __func__: 1345.
     attribute.  (Contributed by Amaury Forgeot d’Arc, after a
     suggestion by George Sakkis; bpo-5982(16).)

   * When a restricted set of attributes were set using ‘__slots__’,
     deleting an unset attribute would not raise *note AttributeError:
     34e. as you would expect.  Fixed by Benjamin Peterson;
     bpo-7604(17).)

   * Two new encodings are now supported: “cp720”, used primarily for
     Arabic text; and “cp858”, a variant of CP 850 that adds the euro
     symbol.  (CP720 contributed by Alexander Belchenko and Amaury
     Forgeot d’Arc in bpo-1616979(18); CP858 contributed by Tim Hatch in
     bpo-8016(19).)

   * The ‘file’ object will now set the ‘filename’ attribute on the
     *note IOError: 1090. exception when trying to open a directory on
     POSIX platforms (noted by Jan Kaliszewski; bpo-4764(20)), and now
     explicitly checks for and forbids writing to read-only file objects
     instead of trusting the C library to catch and report the error
     (fixed by Stefan Krah; bpo-5677(21)).

   * The Python tokenizer now translates line endings itself, so the
     *note compile(): 192. built-in function now accepts code using any
     line-ending convention.  Additionally, it no longer requires that
     the code end in a newline.

   * Extra parentheses in function definitions are illegal in Python
     3.x, meaning that you get a syntax error from ‘def f((x)): pass’.
     In Python3-warning mode, Python 2.7 will now warn about this odd
     usage.  (Noted by James Lingard; bpo-7362(22).)

   * It’s now possible to create weak references to old-style class
     objects.  New-style classes were always weak-referenceable.  (Fixed
     by Antoine Pitrou; bpo-8268(23).)

   * When a module object is garbage-collected, the module’s dictionary
     is now only cleared if no one else is holding a reference to the
     dictionary (bpo-7140(24)).

* Menu:

* Interpreter Changes::
* Optimizations: Optimizations<13>.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2335

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2333

   (3) https://bugs.python.org/issue?@action=redirect&bpo=7117

   (4) https://bugs.python.org/issue?@action=redirect&bpo=3166

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1811

   (6) https://bugs.python.org/issue?@action=redirect&bpo=5211

   (7) https://bugs.python.org/issue?@action=redirect&bpo=5237

   (8) https://bugs.python.org/issue?@action=redirect&bpo=1588

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7988

   (10) https://bugs.python.org/issue?@action=redirect&bpo=3382

   (11) https://bugs.python.org/issue?@action=redirect&bpo=7994

   (12) https://bugs.python.org/issue?@action=redirect&bpo=3439

   (13) https://bugs.python.org/issue?@action=redirect&bpo=7902

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1583863

   (15) https://bugs.python.org/issue?@action=redirect&bpo=4759

   (16) https://bugs.python.org/issue?@action=redirect&bpo=5982

   (17) https://bugs.python.org/issue?@action=redirect&bpo=7604

   (18) https://bugs.python.org/issue?@action=redirect&bpo=1616979

   (19) https://bugs.python.org/issue?@action=redirect&bpo=8016

   (20) https://bugs.python.org/issue?@action=redirect&bpo=4764

   (21) https://bugs.python.org/issue?@action=redirect&bpo=5677

   (22) https://bugs.python.org/issue?@action=redirect&bpo=7362

   (23) https://bugs.python.org/issue?@action=redirect&bpo=8268

   (24) https://bugs.python.org/issue?@action=redirect&bpo=7140


File: python.info,  Node: Interpreter Changes,  Next: Optimizations<13>,  Up: Other Language Changes<14>

1.15.10.1 Interpreter Changes
.............................

A new environment variable, *note PYTHONWARNINGS: bc8, allows
controlling warnings.  It should be set to a string containing warning
settings, equivalent to those used with the *note -W: 8d0. switch,
separated by commas.  (Contributed by Brian Curtin; bpo-7301(1).)

For example, the following setting will print warnings every time they
occur, but turn warnings from the *note Cookie: 71. module into an
error.  (The exact syntax for setting an environment variable varies
across operating systems and shells.)

     export PYTHONWARNINGS=all,error:::Cookie:0

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=7301


File: python.info,  Node: Optimizations<13>,  Prev: Interpreter Changes,  Up: Other Language Changes<14>

1.15.10.2 Optimizations
.......................

Several performance enhancements have been added:

   * A new opcode was added to perform the initial setup for *note with:
     5d5. statements, looking up the *note __enter__(): 5cb. and *note
     __exit__(): 1349. methods.  (Contributed by Benjamin Peterson.)

   * The garbage collector now performs better for one common usage
     pattern: when many objects are being allocated without deallocating
     any of them.  This would previously take quadratic time for garbage
     collection, but now the number of full garbage collections is
     reduced as the number of objects on the heap grows.  The new logic
     only performs a full garbage collection pass when the middle
     generation has been collected 10 times and when the number of
     survivor objects from the middle generation exceeds 10% of the
     number of objects in the oldest generation.  (Suggested by Martin
     von Löwis and implemented by Antoine Pitrou; bpo-4074(1).)

   * The garbage collector tries to avoid tracking simple containers
     which can’t be part of a cycle.  In Python 2.7, this is now true
     for tuples and dicts containing atomic types (such as ints,
     strings, etc.).  Transitively, a dict containing tuples of atomic
     types won’t be tracked either.  This helps reduce the cost of each
     garbage collection by decreasing the number of objects to be
     considered and traversed by the collector.  (Contributed by Antoine
     Pitrou; bpo-4688(2).)

   * Long integers are now stored internally either in base ‘2**15’ or
     in base ‘2**30’, the base being determined at build time.
     Previously, they were always stored in base ‘2**15’.  Using base
     ‘2**30’ gives significant performance improvements on 64-bit
     machines, but benchmark results on 32-bit machines have been mixed.
     Therefore, the default is to use base ‘2**30’ on 64-bit machines
     and base ‘2**15’ on 32-bit machines; on Unix, there’s a new
     configure option ‘--enable-big-digits’ that can be used to override
     this default.

     Apart from the performance improvements this change should be
     invisible to end users, with one exception: for testing and
     debugging purposes there’s a new structseq ‘sys.long_info’ that
     provides information about the internal format, giving the number
     of bits per digit and the size in bytes of the C type used to store
     each digit:

          >>> import sys
          >>> sys.long_info
          sys.long_info(bits_per_digit=30, sizeof_digit=4)

     (Contributed by Mark Dickinson; bpo-4258(3).)

     Another set of changes made long objects a few bytes smaller: 2
     bytes smaller on 32-bit systems and 6 bytes on 64-bit.
     (Contributed by Mark Dickinson; bpo-5260(4).)

   * The division algorithm for long integers has been made faster by
     tightening the inner loop, doing shifts instead of multiplications,
     and fixing an unnecessary extra iteration.  Various benchmarks show
     speedups of between 50% and 150% for long integer divisions and
     modulo operations.  (Contributed by Mark Dickinson; bpo-5512(5).)
     Bitwise operations are also significantly faster (initial patch by
     Gregory Smith; bpo-1087418(6)).

   * The implementation of ‘%’ checks for the left-side operand being a
     Python string and special-cases it; this results in a 1–3%
     performance increase for applications that frequently use ‘%’ with
     strings, such as templating libraries.  (Implemented by Collin
     Winter; bpo-5176(7).)

   * List comprehensions with an ‘if’ condition are compiled into faster
     bytecode.  (Patch by Antoine Pitrou, back-ported to 2.7 by Jeffrey
     Yasskin; bpo-4715(8).)

   * Converting an integer or long integer to a decimal string was made
     faster by special-casing base 10 instead of using a generalized
     conversion function that supports arbitrary bases.  (Patch by
     Gawain Bolton; bpo-6713(9).)

   * The ‘split()’, ‘replace()’, ‘rindex()’, ‘rpartition()’, and
     ‘rsplit()’ methods of string-like types (strings, Unicode strings,
     and *note bytearray: 2ea. objects) now use a fast reverse-search
     algorithm instead of a character-by-character scan.  This is
     sometimes faster by a factor of 10.  (Added by Florent Xicluna;
     bpo-7462(10) and bpo-7622(11).)

   * The *note pickle: a6. and ‘cPickle’ modules now automatically
     intern the strings used for attribute names, reducing memory usage
     of the objects resulting from unpickling.  (Contributed by Jake
     McGuire; bpo-5084(12).)

   * The ‘cPickle’ module now special-cases dictionaries, nearly halving
     the time required to pickle them.  (Contributed by Collin Winter;
     bpo-5670(13).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4074

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4688

   (3) https://bugs.python.org/issue?@action=redirect&bpo=4258

   (4) https://bugs.python.org/issue?@action=redirect&bpo=5260

   (5) https://bugs.python.org/issue?@action=redirect&bpo=5512

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1087418

   (7) https://bugs.python.org/issue?@action=redirect&bpo=5176

   (8) https://bugs.python.org/issue?@action=redirect&bpo=4715

   (9) https://bugs.python.org/issue?@action=redirect&bpo=6713

   (10) https://bugs.python.org/issue?@action=redirect&bpo=7462

   (11) https://bugs.python.org/issue?@action=redirect&bpo=7622

   (12) https://bugs.python.org/issue?@action=redirect&bpo=5084

   (13) https://bugs.python.org/issue?@action=redirect&bpo=5670


File: python.info,  Node: New and Improved Modules,  Next: Build and C API Changes<8>,  Prev: Other Language Changes<14>,  Up: What’s New in Python 2 7

1.15.11 New and Improved Modules
--------------------------------

As in every release, Python’s standard library received a number of
enhancements and bug fixes.  Here’s a partial list of the most notable
changes, sorted alphabetically by module name.  Consult the ‘Misc/NEWS’
file in the source tree for a more complete list of changes, or look
through the Subversion logs for all the details.

   * The *note bdb: f. module’s base debugging class *note Bdb: 134b.
     gained a feature for skipping modules.  The constructor now takes
     an iterable containing glob-style patterns such as ‘django.*’; the
     debugger will not step into stack frames from a module that matches
     one of these patterns.  (Contributed by Maru Newby after a
     suggestion by Senthil Kumaran; bpo-5142(1).)

   * The *note binascii: 10. module now supports the buffer API, so it
     can be used with *note memoryview: 2eb. instances and other similar
     buffer objects.  (Backported from 3.x by Florent Xicluna;
     bpo-7703(2).)

   * Updated module: the ‘bsddb’ module has been updated from
     4.7.2devel9 to version 4.8.4 of the pybsddb package(3).  The new
     version features better Python 3.x compatibility, various bug
     fixes, and adds several new BerkeleyDB flags and methods.  (Updated
     by Jesús Cea Avión; bpo-8156(4).  The pybsddb changelog can be read
     at ‘https://hg.jcea.es/pybsddb/file/tip/ChangeLog’.)

   * The *note bz2: 13. module’s *note BZ2File: 86d. now supports the
     context management protocol, so you can write ‘with
     bz2.BZ2File(...) as f:’.  (Contributed by Hagen Fürstenau;
     bpo-3860(5).)

   * New class: the *note Counter: 10d5. class in the *note collections:
     1d. module is useful for tallying data.  ‘Counter’ instances behave
     mostly like dictionaries but return zero for missing keys instead
     of raising a *note KeyError: 345.:

          >>> from collections import Counter
          >>> c = Counter()
          >>> for letter in 'here is a sample of english text':
          ...   c[letter] += 1
          ...
          >>> c
          Counter({' ': 6, 'e': 5, 's': 3, 'a': 2, 'i': 2, 'h': 2,
          'l': 2, 't': 2, 'g': 1, 'f': 1, 'm': 1, 'o': 1, 'n': 1,
          'p': 1, 'r': 1, 'x': 1})
          >>> c['e']
          5
          >>> c['z']
          0

     There are three additional *note Counter: 10d5. methods.  *note
     most_common(): 134c. returns the N most common elements and their
     counts.  *note elements(): 134d. returns an iterator over the
     contained elements, repeating each element as many times as its
     count.  *note subtract(): 1223. takes an iterable and subtracts one
     for each element instead of adding; if the argument is a dictionary
     or another ‘Counter’, the counts are subtracted.

          >>> c.most_common(5)
          [(' ', 6), ('e', 5), ('s', 3), ('a', 2), ('i', 2)]
          >>> c.elements() ->
             'a', 'a', ' ', ' ', ' ', ' ', ' ', ' ',
             'e', 'e', 'e', 'e', 'e', 'g', 'f', 'i', 'i',
             'h', 'h', 'm', 'l', 'l', 'o', 'n', 'p', 's',
             's', 's', 'r', 't', 't', 'x'
          >>> c['e']
          5
          >>> c.subtract('very heavy on the letter e')
          >>> c['e']    # Count is now lower
          -1

     Contributed by Raymond Hettinger; bpo-1696199(6).

     New class: *note OrderedDict: 5de. is described in the earlier
     section *note PEP 372; Adding an Ordered Dictionary to collections:
     1332.

     New method: The *note deque: 5df. data type now has a *note
     count(): 1225. method that returns the number of contained elements
     equal to the supplied argument 'x', and a *note reverse(): 1226.
     method that reverses the elements of the deque in-place.  ‘deque’
     also exposes its maximum length as the read-only *note maxlen:
     134e. attribute.  (Both features added by Raymond Hettinger.)

     The *note namedtuple: 1ca. class now has an optional 'rename'
     parameter.  If 'rename' is true, field names that are invalid
     because they’ve been repeated or aren’t legal Python identifiers
     will be renamed to legal names that are derived from the field’s
     position within the list of fields:

          >>> from collections import namedtuple
          >>> T = namedtuple('T', ['field1', '$illegal', 'for', 'field2'], rename=True)
          >>> T._fields
          ('field1', '_1', '_2', 'field2')

     (Added by Raymond Hettinger; bpo-1818(7).)

     Finally, the *note Mapping: 8d3. abstract base class now returns
     *note NotImplemented: 7d6. if a mapping is compared to another type
     that isn’t a ‘Mapping’.  (Fixed by Daniel Stutzbach; bpo-8729(8).)

   * Constructors for the parsing classes in the *note ConfigParser: 22.
     module now take an 'allow_no_value' parameter, defaulting to false;
     if true, options without values will be allowed.  For example:

          >>> import ConfigParser, StringIO
          >>> sample_config = """
          ... [mysqld]
          ... user = mysql
          ... pid-file = /var/run/mysqld/mysqld.pid
          ... skip-bdb
          ... """
          >>> config = ConfigParser.RawConfigParser(allow_no_value=True)
          >>> config.readfp(StringIO.StringIO(sample_config))
          >>> config.get('mysqld', 'user')
          'mysql'
          >>> print config.get('mysqld', 'skip-bdb')
          None
          >>> print config.get('mysqld', 'unknown')
          Traceback (most recent call last):
            ...
          NoOptionError: No option 'unknown' in section: 'mysqld'

     (Contributed by Mats Kindahl; bpo-7005(9).)

   * Deprecated function: ‘contextlib.nested()’, which allows handling
     more than one context manager with a single *note with: 5d5.
     statement, has been deprecated, because the ‘with’ statement now
     supports multiple context managers.

   * The *note cookielib: 70. module now ignores cookies that have an
     invalid version field, one that doesn’t contain an integer value.
     (Fixed by John J. Lee; bpo-3924(10).)

   * The *note copy: 25. module’s *note deepcopy(): b8a. function will
     now correctly copy bound instance methods.  (Implemented by Robert
     Collins; bpo-1515(11).)

   * The *note ctypes: 2a. module now always converts ‘None’ to a C
     ‘NULL’ pointer for arguments declared as pointers.  (Changed by
     Thomas Heller; bpo-4606(12).)  The underlying libffi library(13)
     has been updated to version 3.0.9, containing various fixes for
     different platforms.  (Updated by Matthias Klose; bpo-8142(14).)

   * New method: the *note datetime: 30. module’s *note timedelta: 9da.
     class gained a *note total_seconds(): 134f. method that returns the
     number of seconds in the duration.  (Contributed by Brian Quinlan;
     bpo-5788(15).)

   * New method: the *note Decimal: 29d. class gained a *note
     from_float(): 1249. class method that performs an exact conversion
     of a floating-point number to a ‘Decimal’.  This exact conversion
     strives for the closest decimal approximation to the floating-point
     representation’s value; the resulting decimal value will therefore
     still include the inaccuracy, if any.  For example,
     ‘Decimal.from_float(0.1)’ returns
     ‘Decimal('0.1000000000000000055511151231257827021181583404541015625')’.
     (Implemented by Raymond Hettinger; bpo-4796(16).)

     Comparing instances of *note Decimal: 29d. with floating-point
     numbers now produces sensible results based on the numeric values
     of the operands.  Previously such comparisons would fall back to
     Python’s default rules for comparing objects, which produced
     arbitrary results based on their type.  Note that you still cannot
     combine ‘Decimal’ and floating point in other operations such as
     addition, since you should be explicitly choosing how to convert
     between float and ‘Decimal’.  (Fixed by Mark Dickinson;
     bpo-2531(17).)

     The constructor for *note Decimal: 29d. now accepts floating-point
     numbers (added by Raymond Hettinger; bpo-8257(18)) and non-European
     Unicode characters such as Arabic-Indic digits (contributed by Mark
     Dickinson; bpo-6595(19)).

     Most of the methods of the *note Context: 10f3. class now accept
     integers as well as *note Decimal: 29d. instances; the only
     exceptions are the *note canonical(): 1350. and *note
     is_canonical(): 1351. methods.  (Patch by Juan José Conti;
     bpo-7633(20).)

     When using *note Decimal: 29d. instances with a string’s *note
     format(): 624. method, the default alignment was previously
     left-alignment.  This has been changed to right-alignment, which is
     more sensible for numeric types.  (Changed by Mark Dickinson;
     bpo-6857(21).)

     Comparisons involving a signaling NaN value (or ‘sNAN’) now signal
     *note InvalidOperation: 10ec. instead of silently returning a true
     or false value depending on the comparison operator.  Quiet NaN
     values (or ‘NaN’) are now hashable.  (Fixed by Mark Dickinson;
     bpo-7279(22).)

   * The *note difflib: 37. module now produces output that is more
     compatible with modern ‘diff’/‘patch’ tools through one small
     change, using a tab character instead of spaces as a separator in
     the header giving the filename.  (Fixed by Anatoly Techtonik;
     bpo-7585(23).)

   * The Distutils ‘sdist’ command now always regenerates the ‘MANIFEST’
     file, since even if the ‘MANIFEST.in’ or ‘setup.py’ files haven’t
     been modified, the user might have created some new files that
     should be included.  (Fixed by Tarek Ziadé; bpo-8688(24).)

   * The *note doctest: 3a. module’s *note IGNORE_EXCEPTION_DETAIL:
     1352. flag will now ignore the name of the module containing the
     exception being tested.  (Patch by Lennart Regebro; bpo-7490(25).)

   * The *note email: 3b. module’s *note Message: 27c. class will now
     accept a Unicode-valued payload, automatically converting the
     payload to the encoding specified by ‘output_charset’.  (Added by
     R.  David Murray; bpo-1368247(26).)

   * The *note Fraction: 1e7. class now accepts a single float or *note
     Decimal: 29d. instance, or two rational numbers, as arguments to
     its constructor.  (Implemented by Mark Dickinson; rationals added
     in bpo-5812(27), and float/decimal in bpo-8294(28).)

     Ordering comparisons (‘<’, ‘<=’, ‘>’, ‘>=’) between fractions and
     complex numbers now raise a *note TypeError: 2c3.  This fixes an
     oversight, making the *note Fraction: 1e7. match the other numeric
     types.

   * New class: *note FTP_TLS: 904. in the *note ftplib: 5e. module
     provides secure FTP connections using TLS encapsulation of
     authentication as well as subsequent control and data transfers.
     (Contributed by Giampaolo Rodola; bpo-2054(29).)

     The *note storbinary(): 1353. method for binary uploads can now
     restart uploads thanks to an added 'rest' parameter (patch by Pablo
     Mouzo; bpo-6845(30).)

   * New class decorator: *note total_ordering(): f7a. in the *note
     functools: 5f. module takes a class that defines an *note __eq__():
     b13. method and one of *note __lt__(): 12e7, *note __le__(): 1354,
     *note __gt__(): 1355, or *note __ge__(): 1356, and generates the
     missing comparison methods.  Since the ‘__cmp__()’ method is being
     deprecated in Python 3.x, this decorator makes it easier to define
     ordered classes.  (Added by Raymond Hettinger; bpo-5479(31).)

     New function: *note cmp_to_key(): 121f. will take an old-style
     comparison function that expects two arguments and return a new
     callable that can be used as the 'key' parameter to functions such
     as *note sorted(): bed, *note min(): f3f. and *note max(): f40,
     etc.  The primary intended use is to help with making code
     compatible with Python 3.x.  (Added by Raymond Hettinger.)

   * New function: the *note gc: 60. module’s *note is_tracked(): 1357.
     returns true if a given instance is tracked by the garbage
     collector, false otherwise.  (Contributed by Antoine Pitrou;
     bpo-4688(32).)

   * The *note gzip: 67. module’s *note GzipFile: 41d. now supports the
     context management protocol, so you can write ‘with
     gzip.GzipFile(...) as f:’ (contributed by Hagen Fürstenau;
     bpo-3860(33)), and it now implements the *note io.BufferedIOBase:
     697. ABC, so you can wrap it with *note io.BufferedReader: 1253.
     for faster processing (contributed by Nir Aides; bpo-7471(34)).
     It’s also now possible to override the modification time recorded
     in a gzipped file by providing an optional timestamp to the
     constructor.  (Contributed by Jacques Frechet; bpo-4272(35).)

     Files in gzip format can be padded with trailing zero bytes; the
     *note gzip: 67. module will now consume these trailing bytes.
     (Fixed by Tadek Pietraszek and Brian Curtin; bpo-2846(36).)

   * New attribute: the *note hashlib: 68. module now has an
     ‘algorithms’ attribute containing a tuple naming the supported
     algorithms.  In Python 2.7, ‘hashlib.algorithms’ contains ‘('md5',
     'sha1', 'sha224', 'sha256', 'sha384', 'sha512')’.  (Contributed by
     Carl Chenet; bpo-7418(37).)

   * The default *note HTTPResponse: 1112. class used by the *note
     httplib: 6e. module now supports buffering, resulting in much
     faster reading of HTTP responses.  (Contributed by Kristján Valur
     Jónsson; bpo-4879(38).)

     The *note HTTPConnection: b59. and *note HTTPSConnection: b5a.
     classes now support a 'source_address' parameter, a ‘(host, port)’
     2-tuple giving the source address that will be used for the
     connection.  (Contributed by Eldon Ziegler; bpo-3972(39).)

   * The ‘ihooks’ module now supports relative imports.  Note that
     ‘ihooks’ is an older module for customizing imports, superseded by
     the ‘imputil’ module added in Python 2.0.  (Relative import support
     added by Neil Schemenauer.)

   * The *note imaplib: 74. module now supports IPv6 addresses.
     (Contributed by Derek Morr; bpo-1655(40).)

   * New function: the *note inspect: 7e. module’s *note getcallargs():
     ef2. takes a callable and its positional and keyword arguments, and
     figures out which of the callable’s parameters will receive each
     argument, returning a dictionary mapping argument names to their
     values.  For example:

          >>> from inspect import getcallargs
          >>> def f(a, b=1, *pos, **named):
          ...     pass
          ...
          >>> getcallargs(f, 1, 2, 3)
          {'a': 1, 'b': 2, 'pos': (3,), 'named': {}}
          >>> getcallargs(f, a=2, x=4)
          {'a': 2, 'b': 1, 'pos': (), 'named': {'x': 4}}
          >>> getcallargs(f)
          Traceback (most recent call last):
          ...
          TypeError: f() takes at least 1 argument (0 given)

     Contributed by George Sakkis; bpo-3135(41).

   * Updated module: The *note io: 7f. library has been upgraded to the
     version shipped with Python 3.1.  For 3.1, the I/O library was
     entirely rewritten in C and is 2 to 20 times faster depending on
     the task being performed.  The original Python version was renamed
     to the ‘_pyio’ module.

     One minor resulting change: the *note io.TextIOBase: 698. class now
     has an *note errors: 1358. attribute giving the error setting used
     for encoding and decoding errors (one of ‘'strict'’, ‘'replace'’,
     ‘'ignore'’).

     The *note io.FileIO: 1359. class now raises an *note OSError: 41a.
     when passed an invalid file descriptor.  (Implemented by Benjamin
     Peterson; bpo-4991(42).)  The *note truncate(): 135a. method now
     preserves the file position; previously it would change the file
     position to the end of the new file.  (Fixed by Pascal Chambon;
     bpo-6939(43).)

   * New function: ‘itertools.compress(data, selectors)’ takes two
     iterators.  Elements of 'data' are returned if the corresponding
     value in 'selectors' is true:

          itertools.compress('ABCDEF', [1,0,1,0,1,1]) =>
            A, C, E, F

     New function: ‘itertools.combinations_with_replacement(iter, r)’
     returns all the possible 'r'-length combinations of elements from
     the iterable 'iter'.  Unlike *note combinations(): 135b, individual
     elements can be repeated in the generated combinations:

          itertools.combinations_with_replacement('abc', 2) =>
            ('a', 'a'), ('a', 'b'), ('a', 'c'),
            ('b', 'b'), ('b', 'c'), ('c', 'c')

     Note that elements are treated as unique depending on their
     position in the input, not their actual values.

     The *note itertools.count(): 12ca. function now has a 'step'
     argument that allows incrementing by values other than 1.
     ‘count()’ also now allows keyword arguments, and using non-integer
     values such as floats or *note Decimal: 29d. instances.
     (Implemented by Raymond Hettinger; bpo-5032(44).)

     *note itertools.combinations(): 135b. and *note
     itertools.product(): 135c. previously raised *note ValueError: 202.
     for values of 'r' larger than the input iterable.  This was deemed
     a specification error, so they now return an empty iterator.
     (Fixed by Raymond Hettinger; bpo-4816(45).)

   * Updated module: The *note json: 82. module was upgraded to version
     2.0.9 of the simplejson package, which includes a C extension that
     makes encoding and decoding faster.  (Contributed by Bob Ippolito;
     bpo-4136(46).)

     To support the new *note collections.OrderedDict: 5de. type, *note
     json.load(): cda. now has an optional 'object_pairs_hook' parameter
     that will be called with any object literal that decodes to a list
     of pairs.  (Contributed by Raymond Hettinger; bpo-5381(47).)

   * The *note mailbox: 8b. module’s *note Maildir: 41f. class now
     records the timestamp on the directories it reads, and only
     re-reads them if the modification time has subsequently changed.
     This improves performance by avoiding unneeded directory scans.
     (Fixed by A.M. Kuchling and Antoine Pitrou; bpo-1607951(48),
     bpo-6896(49).)

   * New functions: the *note math: 8e. module gained *note erf(): bf9.
     and *note erfc(): bfa. for the error function and the complementary
     error function, *note expm1(): 1231. which computes ‘e**x - 1’ with
     more precision than using *note exp(): 135d. and subtracting 1,
     *note gamma(): 1232. for the Gamma function, and *note lgamma():
     1233. for the natural log of the Gamma function.  (Contributed by
     Mark Dickinson and nirinA raseliarison; bpo-3366(50).)

   * The *note multiprocessing: 94. module’s ‘Manager*’ classes can now
     be passed a callable that will be called whenever a subprocess is
     started, along with a set of arguments that will be passed to the
     callable.  (Contributed by lekma; bpo-5585(51).)

     The *note Pool: fa4. class, which controls a pool of worker
     processes, now has an optional 'maxtasksperchild' parameter.
     Worker processes will perform the specified number of tasks and
     then exit, causing the ‘Pool’ to start a new worker.  This is
     useful if tasks may leak memory or other resources, or if some
     tasks will cause the worker to become very large.  (Contributed by
     Charles Cazabon; bpo-6963(52).)

   * The ‘nntplib’ module now supports IPv6 addresses.  (Contributed by
     Derek Morr; bpo-1664(53).)

   * New functions: the *note os: a1. module wraps the following POSIX
     system calls: *note getresgid(): 135e. and *note getresuid(): 135f,
     which return the real, effective, and saved GIDs and UIDs; *note
     setresgid(): 1360. and *note setresuid(): 1361, which set real,
     effective, and saved GIDs and UIDs to new values; *note
     initgroups(): 1362, which initialize the group access list for the
     current process.  (GID/UID functions contributed by Travis H.;
     bpo-6508(54).  Support for initgroups added by Jean-Paul Calderone;
     bpo-7333(55).)

     The *note os.fork(): 197. function now re-initializes the import
     lock in the child process; this fixes problems on Solaris when
     ‘fork()’ is called from a thread.  (Fixed by Zsolt Cserna;
     bpo-7242(56).)

   * In the *note os.path: a2. module, the *note normpath(): 1363. and
     *note abspath(): 1364. functions now preserve Unicode; if their
     input path is a Unicode string, the return value is also a Unicode
     string.  (*note normpath(): 1363. fixed by Matt Giuca in
     bpo-5827(57); *note abspath(): 1364. fixed by Ezio Melotti in
     bpo-3426(58).)

   * The *note pydoc: b5. module now has help for the various symbols
     that Python uses.  You can now do ‘help('<<')’ or ‘help('@')’, for
     example.  (Contributed by David Laban; bpo-4739(59).)

   * The *note re: b9. module’s *note split(): 2a2, *note sub(): 2a3,
     and *note subn(): 2a4. now accept an optional 'flags' argument, for
     consistency with the other functions in the module.  (Added by
     Gregory P. Smith.)

   * New function: *note run_path(): 181. in the *note runpy: be. module
     will execute the code at a provided 'path' argument.  'path' can be
     the path of a Python source file (‘example.py’), a compiled
     bytecode file (‘example.pyc’), a directory (‘./package/’), or a zip
     archive (‘example.zip’).  If a directory or zip path is provided,
     it will be added to the front of ‘sys.path’ and the module *note
     __main__: 1. will be imported.  It’s expected that the directory or
     zip contains a ‘__main__.py’; if it doesn’t, some other
     ‘__main__.py’ might be imported from a location later in
     ‘sys.path’.  This makes more of the machinery of ‘runpy’ available
     to scripts that want to mimic the way Python’s command line
     processes an explicit path name.  (Added by Nick Coghlan;
     bpo-6816(60).)

   * New function: in the *note shutil: c5. module, *note
     make_archive(): 4b6. takes a filename, archive type (zip or
     tar-format), and a directory path, and creates an archive
     containing the directory’s contents.  (Added by Tarek Ziadé.)

     *note shutil: c5.’s *note copyfile(): a67. and *note copytree():
     a36. functions now raise a *note SpecialFileError: 1365. exception
     when asked to copy a named pipe.  Previously the code would treat
     named pipes like a regular file by opening them for reading, and
     this would block indefinitely.  (Fixed by Antoine Pitrou;
     bpo-3002(61).)

   * The *note signal: c6. module no longer re-installs the signal
     handler unless this is truly necessary, which fixes a bug that
     could make it impossible to catch the EINTR signal robustly.
     (Fixed by Charles-Francois Natali; bpo-8354(62).)

   * New functions: in the *note site: c7. module, three new functions
     return various site- and user-specific paths.  *note
     getsitepackages(): 1284. returns a list containing all global
     site-packages directories, *note getusersitepackages(): 1286.
     returns the path of the user’s site-packages directory, and *note
     getuserbase(): 1285. returns the value of the *note USER_BASE:
     1366. environment variable, giving the path to a directory that can
     be used to store data.  (Contributed by Tarek Ziadé; bpo-6693(63).)

     The *note site: c7. module now reports exceptions occurring when
     the *note sitecustomize: c8. module is imported, and will no longer
     catch and swallow the *note KeyboardInterrupt: 9dc. exception.
     (Fixed by Victor Stinner; bpo-3137(64).)

   * The *note create_connection(): 675. function gained a
     'source_address' parameter, a ‘(host, port)’ 2-tuple giving the
     source address that will be used for the connection.  (Contributed
     by Eldon Ziegler; bpo-3972(65).)

     The *note recv_into(): 1367. and *note recvfrom_into(): 1368.
     methods will now write into objects that support the buffer API,
     most usefully the *note bytearray: 2ea. and *note memoryview: 2eb.
     objects.  (Implemented by Antoine Pitrou; bpo-8104(66).)

   * The *note SocketServer: cd. module’s *note TCPServer: 1369. class
     now supports socket timeouts and disabling the Nagle algorithm.
     The ‘disable_nagle_algorithm’ class attribute defaults to ‘False’;
     if overridden to be true, new request connections will have the
     TCP_NODELAY option set to prevent buffering many small sends into a
     single TCP packet.  The *note timeout: 136a. class attribute can
     hold a timeout in seconds that will be applied to the request
     socket; if no request is received within that time, *note
     handle_timeout(): 136b. will be called and *note handle_request():
     136c. will return.  (Contributed by Kristján Valur Jónsson;
     bpo-6192(67) and bpo-6267(68).)

   * Updated module: the *note sqlite3: cf. module has been updated to
     version 2.6.0 of the pysqlite package(69).  Version 2.6.0 includes
     a number of bugfixes, and adds the ability to load SQLite
     extensions from shared libraries.  Call the
     ‘enable_load_extension(True)’ method to enable extensions, and then
     call *note load_extension(): 4bb. to load a particular shared
     library.  (Updated by Gerhard Häring.)

   * The *note ssl: d0. module’s *note SSLSocket: 8f3. objects now
     support the buffer API, which fixed a test suite failure (fix by
     Antoine Pitrou; bpo-7133(70)) and automatically set OpenSSL’s
     ‘SSL_MODE_AUTO_RETRY’, which will prevent an error code being
     returned from ‘recv()’ operations that trigger an SSL renegotiation
     (fix by Antoine Pitrou; bpo-8222(71)).

     The *note wrap_socket(): 528. constructor function now takes a
     'ciphers' argument that’s a string listing the encryption
     algorithms to be allowed; the format of the string is described in
     the OpenSSL documentation(72).  (Added by Antoine Pitrou;
     bpo-8322(73).)

     Another change makes the extension load all of OpenSSL’s ciphers
     and digest algorithms so that they’re all available.  Some SSL
     certificates couldn’t be verified, reporting an “unknown algorithm”
     error.  (Reported by Beda Kosata, and fixed by Antoine Pitrou;
     bpo-8484(74).)

     The version of OpenSSL being used is now available as the module
     attributes *note ssl.OPENSSL_VERSION: 1264. (a string), *note
     ssl.OPENSSL_VERSION_INFO: 1265. (a 5-tuple), and *note
     ssl.OPENSSL_VERSION_NUMBER: 1266. (an integer).  (Added by Antoine
     Pitrou; bpo-8321(75).)

   * The *note struct: d5. module will no longer silently ignore
     overflow errors when a value is too large for a particular integer
     format code (one of ‘bBhHiIlLqQ’); it now always raises a *note
     struct.error: 136d. exception.  (Changed by Mark Dickinson;
     bpo-1523(76).)  The *note pack(): 12bd. function will also attempt
     to use *note __index__(): 720. to convert and pack non-integers
     before trying the *note __int__(): 71f. method or reporting an
     error.  (Changed by Mark Dickinson; bpo-8300(77).)

   * New function: the *note subprocess: d6. module’s *note
     check_output(): ffb. runs a command with a specified set of
     arguments and returns the command’s output as a string when the
     command runs without error, or raises a *note CalledProcessError:
     136e. exception otherwise.

          >>> subprocess.check_output(['df', '-h', '.'])
          'Filesystem     Size   Used  Avail Capacity  Mounted on\n
          /dev/disk0s2    52G    49G   3.0G    94%    /\n'

          >>> subprocess.check_output(['df', '-h', '/bogus'])
            ...
          subprocess.CalledProcessError: Command '['df', '-h', '/bogus']' returned non-zero exit status 1

     (Contributed by Gregory P. Smith.)

     The *note subprocess: d6. module will now retry its internal system
     calls on receiving an *note EINTR: db5. signal.  (Reported by
     several people; final patch by Gregory P. Smith in
     bpo-1068268(78).)

   * New function: *note is_declared_global(): 136f. in the *note
     symtable: d8. module returns true for variables that are explicitly
     declared to be global, false for ones that are implicitly global.
     (Contributed by Jeremy Hylton.)

   * The *note syslog: dc. module will now use the value of
     ‘sys.argv[0]’ as the identifier instead of the previous default
     value of ‘'python'’.  (Changed by Sean Reifschneider;
     bpo-8451(79).)

   * The *note sys.version_info: 6a3. value is now a named tuple, with
     attributes named ‘major’, ‘minor’, ‘micro’, ‘releaselevel’, and
     ‘serial’.  (Contributed by Ross Light; bpo-4285(80).)

     *note sys.getwindowsversion(): d0e. also returns a named tuple,
     with attributes named ‘major’, ‘minor’, ‘build’, ‘platform’,
     ‘service_pack’, ‘service_pack_major’, ‘service_pack_minor’,
     ‘suite_mask’, and ‘product_type’.  (Contributed by Brian Curtin;
     bpo-7766(81).)

   * The *note tarfile: de. module’s default error handling has changed,
     to no longer suppress fatal errors.  The default error level was
     previously 0, which meant that errors would only result in a
     message being written to the debug log, but because the debug log
     is not activated by default, these errors go unnoticed.  The
     default error level is now 1, which raises an exception if there’s
     an error.  (Changed by Lars Gustäbel; bpo-7357(82).)

     *note tarfile: de. now supports filtering the *note TarInfo: 1256.
     objects being added to a tar file.  When you call *note add(): c14,
     you may supply an optional 'filter' argument that’s a callable.
     The 'filter' callable will be passed the ‘TarInfo’ for every file
     being added, and can modify and return it.  If the callable returns
     ‘None’, the file will be excluded from the resulting archive.  This
     is more powerful than the existing 'exclude' argument, which has
     therefore been deprecated.  (Added by Lars Gustäbel; bpo-6856(83).)
     The *note TarFile: 1255. class also now supports the context
     management protocol.  (Added by Lars Gustäbel; bpo-7232(84).)

   * The *note wait(): 1370. method of the *note threading.Event: 119c.
     class now returns the internal flag on exit.  This means the method
     will usually return true because ‘wait()’ is supposed to block
     until the internal flag becomes true.  The return value will only
     be false if a timeout was provided and the operation timed out.
     (Contributed by Tim Lesher; bpo-1674032(85).)

   * The Unicode database provided by the *note unicodedata: 105. module
     is now used internally to determine which characters are numeric,
     whitespace, or represent line breaks.  The database also includes
     information from the ‘Unihan.txt’ data file (patch by Anders
     Chrigström and Amaury Forgeot d’Arc; bpo-1571184(86)) and has been
     updated to version 5.2.0 (updated by Florent Xicluna;
     bpo-8024(87)).

   * The *note urlparse: 10a. module’s *note urlsplit(): d67. now
     handles unknown URL schemes in a fashion compliant with RFC
     3986(88): if the URL is of the form ‘"<something>://..."’, the text
     before the ‘://’ is treated as the scheme, even if it’s a made-up
     scheme that the module doesn’t know about.  This change may break
     code that worked around the old behaviour.  For example, Python
     2.6.4 or 2.5 will return the following:

          >>> import urlparse
          >>> urlparse.urlsplit('invented://host/filename?query')
          ('invented', '', '//host/filename?query', '', '')

     Python 2.7 (and Python 2.6.5) will return:

          >>> import urlparse
          >>> urlparse.urlsplit('invented://host/filename?query')
          ('invented', 'host', '/filename?query', '', '')

     (Python 2.7 actually produces slightly different output, since it
     returns a named tuple instead of a standard tuple.)

     The *note urlparse: 10a. module also supports IPv6 literal
     addresses as defined by RFC 2732(89) (contributed by Senthil
     Kumaran; bpo-2987(90)).

          >>> urlparse.urlparse('http://[1080::8:800:200C:417A]/foo')
          ParseResult(scheme='http', netloc='[1080::8:800:200C:417A]',
                      path='/foo', params='', query='', fragment='')

   * New class: the *note WeakSet: 5e0. class in the *note weakref: 114.
     module is a set that only holds weak references to its elements;
     elements will be removed once there are no references pointing to
     them.  (Originally implemented in Python 3.x by Raymond Hettinger,
     and backported to 2.7 by Michael Foord.)

   * The *note xml.etree.ElementTree: 125. library, no longer escapes
     ampersands and angle brackets when outputting an XML processing
     instruction (which looks like ‘<?xml-stylesheet href="#style1"?>’)
     or comment (which looks like ‘<!-- comment -->’).  (Patch by Neil
     Muller; bpo-2746(91).)

   * The XML-RPC client and server, provided by the *note xmlrpclib:
     12e. and *note SimpleXMLRPCServer: 12f. modules, have improved
     performance by supporting HTTP/1.1 keep-alive and by optionally
     using gzip encoding to compress the XML being exchanged.  The gzip
     compression is controlled by the ‘encode_threshold’ attribute of
     *note SimpleXMLRPCRequestHandler: 1371, which contains a size in
     bytes; responses larger than this will be compressed.  (Contributed
     by Kristján Valur Jónsson; bpo-6267(92).)

   * The *note zipfile: 131. module’s *note ZipFile: 6c7. now supports
     the context management protocol, so you can write ‘with
     zipfile.ZipFile(...) as f:’.  (Contributed by Brian Curtin;
     bpo-5511(93).)

     *note zipfile: 131. now also supports archiving empty directories
     and extracts them correctly.  (Fixed by Kuba Wieczorek;
     bpo-4710(94).)  Reading files out of an archive is faster, and
     interleaving *note read(): 1372. and *note readline(): 1373. now
     works correctly.  (Contributed by Nir Aides; bpo-7610(95).)

     The *note is_zipfile(): 1374. function now accepts a file object,
     in addition to the path names accepted in earlier versions.
     (Contributed by Gabriel Genellina; bpo-4756(96).)

     The *note writestr(): 1375. method now has an optional
     'compress_type' parameter that lets you override the default
     compression method specified in the *note ZipFile: 6c7.
     constructor.  (Contributed by Ronald Oussoren; bpo-6003(97).)

* Menu:

* New module; importlib: New module importlib.
* New module; sysconfig: New module sysconfig.
* ttk; Themed Widgets for Tk: ttk Themed Widgets for Tk.
* Updated module; unittest: Updated module unittest.
* Updated module; ElementTree 1.3: Updated module ElementTree 1 3.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5142

   (2) https://bugs.python.org/issue?@action=redirect&bpo=7703

   (3) https://www.jcea.es/programacion/pybsddb.htm

   (4) https://bugs.python.org/issue?@action=redirect&bpo=8156

   (5) https://bugs.python.org/issue?@action=redirect&bpo=3860

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1696199

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1818

   (8) https://bugs.python.org/issue?@action=redirect&bpo=8729

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7005

   (10) https://bugs.python.org/issue?@action=redirect&bpo=3924

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1515

   (12) https://bugs.python.org/issue?@action=redirect&bpo=4606

   (13) https://sourceware.org/libffi/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=8142

   (15) https://bugs.python.org/issue?@action=redirect&bpo=5788

   (16) https://bugs.python.org/issue?@action=redirect&bpo=4796

   (17) https://bugs.python.org/issue?@action=redirect&bpo=2531

   (18) https://bugs.python.org/issue?@action=redirect&bpo=8257

   (19) https://bugs.python.org/issue?@action=redirect&bpo=6595

   (20) https://bugs.python.org/issue?@action=redirect&bpo=7633

   (21) https://bugs.python.org/issue?@action=redirect&bpo=6857

   (22) https://bugs.python.org/issue?@action=redirect&bpo=7279

   (23) https://bugs.python.org/issue?@action=redirect&bpo=7585

   (24) https://bugs.python.org/issue?@action=redirect&bpo=8688

   (25) https://bugs.python.org/issue?@action=redirect&bpo=7490

   (26) https://bugs.python.org/issue?@action=redirect&bpo=1368247

   (27) https://bugs.python.org/issue?@action=redirect&bpo=5812

   (28) https://bugs.python.org/issue?@action=redirect&bpo=8294

   (29) https://bugs.python.org/issue?@action=redirect&bpo=2054

   (30) https://bugs.python.org/issue?@action=redirect&bpo=6845

   (31) https://bugs.python.org/issue?@action=redirect&bpo=5479

   (32) https://bugs.python.org/issue?@action=redirect&bpo=4688

   (33) https://bugs.python.org/issue?@action=redirect&bpo=3860

   (34) https://bugs.python.org/issue?@action=redirect&bpo=7471

   (35) https://bugs.python.org/issue?@action=redirect&bpo=4272

   (36) https://bugs.python.org/issue?@action=redirect&bpo=2846

   (37) https://bugs.python.org/issue?@action=redirect&bpo=7418

   (38) https://bugs.python.org/issue?@action=redirect&bpo=4879

   (39) https://bugs.python.org/issue?@action=redirect&bpo=3972

   (40) https://bugs.python.org/issue?@action=redirect&bpo=1655

   (41) https://bugs.python.org/issue?@action=redirect&bpo=3135

   (42) https://bugs.python.org/issue?@action=redirect&bpo=4991

   (43) https://bugs.python.org/issue?@action=redirect&bpo=6939

   (44) https://bugs.python.org/issue?@action=redirect&bpo=5032

   (45) https://bugs.python.org/issue?@action=redirect&bpo=4816

   (46) https://bugs.python.org/issue?@action=redirect&bpo=4136

   (47) https://bugs.python.org/issue?@action=redirect&bpo=5381

   (48) https://bugs.python.org/issue?@action=redirect&bpo=1607951

   (49) https://bugs.python.org/issue?@action=redirect&bpo=6896

   (50) https://bugs.python.org/issue?@action=redirect&bpo=3366

   (51) https://bugs.python.org/issue?@action=redirect&bpo=5585

   (52) https://bugs.python.org/issue?@action=redirect&bpo=6963

   (53) https://bugs.python.org/issue?@action=redirect&bpo=1664

   (54) https://bugs.python.org/issue?@action=redirect&bpo=6508

   (55) https://bugs.python.org/issue?@action=redirect&bpo=7333

   (56) https://bugs.python.org/issue?@action=redirect&bpo=7242

   (57) https://bugs.python.org/issue?@action=redirect&bpo=5827

   (58) https://bugs.python.org/issue?@action=redirect&bpo=3426

   (59) https://bugs.python.org/issue?@action=redirect&bpo=4739

   (60) https://bugs.python.org/issue?@action=redirect&bpo=6816

   (61) https://bugs.python.org/issue?@action=redirect&bpo=3002

   (62) https://bugs.python.org/issue?@action=redirect&bpo=8354

   (63) https://bugs.python.org/issue?@action=redirect&bpo=6693

   (64) https://bugs.python.org/issue?@action=redirect&bpo=3137

   (65) https://bugs.python.org/issue?@action=redirect&bpo=3972

   (66) https://bugs.python.org/issue?@action=redirect&bpo=8104

   (67) https://bugs.python.org/issue?@action=redirect&bpo=6192

   (68) https://bugs.python.org/issue?@action=redirect&bpo=6267

   (69) https://github.com/ghaering/pysqlite

   (70) https://bugs.python.org/issue?@action=redirect&bpo=7133

   (71) https://bugs.python.org/issue?@action=redirect&bpo=8222

   (72) https://docs.openssl.org/1.0.2/man1/ciphers/

   (73) https://bugs.python.org/issue?@action=redirect&bpo=8322

   (74) https://bugs.python.org/issue?@action=redirect&bpo=8484

   (75) https://bugs.python.org/issue?@action=redirect&bpo=8321

   (76) https://bugs.python.org/issue?@action=redirect&bpo=1523

   (77) https://bugs.python.org/issue?@action=redirect&bpo=8300

   (78) https://bugs.python.org/issue?@action=redirect&bpo=1068268

   (79) https://bugs.python.org/issue?@action=redirect&bpo=8451

   (80) https://bugs.python.org/issue?@action=redirect&bpo=4285

   (81) https://bugs.python.org/issue?@action=redirect&bpo=7766

   (82) https://bugs.python.org/issue?@action=redirect&bpo=7357

   (83) https://bugs.python.org/issue?@action=redirect&bpo=6856

   (84) https://bugs.python.org/issue?@action=redirect&bpo=7232

   (85) https://bugs.python.org/issue?@action=redirect&bpo=1674032

   (86) https://bugs.python.org/issue?@action=redirect&bpo=1571184

   (87) https://bugs.python.org/issue?@action=redirect&bpo=8024

   (88) https://datatracker.ietf.org/doc/html/rfc3986.html

   (89) https://datatracker.ietf.org/doc/html/rfc2732.html

   (90) https://bugs.python.org/issue?@action=redirect&bpo=2987

   (91) https://bugs.python.org/issue?@action=redirect&bpo=2746

   (92) https://bugs.python.org/issue?@action=redirect&bpo=6267

   (93) https://bugs.python.org/issue?@action=redirect&bpo=5511

   (94) https://bugs.python.org/issue?@action=redirect&bpo=4710

   (95) https://bugs.python.org/issue?@action=redirect&bpo=7610

   (96) https://bugs.python.org/issue?@action=redirect&bpo=4756

   (97) https://bugs.python.org/issue?@action=redirect&bpo=6003


File: python.info,  Node: New module importlib,  Next: New module sysconfig,  Up: New and Improved Modules

1.15.11.1 New module: importlib
...............................

Python 3.1 includes the *note importlib: 77. package, a
re-implementation of the logic underlying Python’s *note import: 5e5.
statement.  ‘importlib’ is useful for implementers of Python
interpreters and to users who wish to write new importers that can
participate in the import process.  Python 2.7 doesn’t contain the
complete ‘importlib’ package, but instead has a tiny subset that
contains a single function, *note import_module(): 51b.

‘import_module(name, package=None)’ imports a module.  'name' is a
string containing the module or package’s name.  It’s possible to do
relative imports by providing a string that begins with a ‘.’ character,
such as ‘..utils.errors’.  For relative imports, the 'package' argument
must be provided and is the name of the package that will be used as the
anchor for the relative import.  *note import_module(): 51b. both
inserts the imported module into ‘sys.modules’ and returns the module
object.

Here are some examples:

     >>> from importlib import import_module
     >>> anydbm = import_module('anydbm')  # Standard absolute import
     >>> anydbm
     <module 'anydbm' from '/p/python/Lib/anydbm.py'>
     >>> # Relative import
     >>> file_util = import_module('..file_util', 'distutils.command')
     >>> file_util
     <module 'distutils.file_util' from '/python/Lib/distutils/file_util.pyc'>

*note importlib: 77. was implemented by Brett Cannon and introduced in
Python 3.1.


File: python.info,  Node: New module sysconfig,  Next: ttk Themed Widgets for Tk,  Prev: New module importlib,  Up: New and Improved Modules

1.15.11.2 New module: sysconfig
...............................

The *note sysconfig: db. module has been pulled out of the Distutils
package, becoming a new top-level module in its own right.  ‘sysconfig’
provides functions for getting information about Python’s build process:
compiler switches, installation paths, the platform name, and whether
Python is running from its source directory.

Some of the functions in the module are:

   * *note get_config_var(): 1068. returns variables from Python’s
     Makefile and the ‘pyconfig.h’ file.

   * *note get_config_vars(): 1069. returns a dictionary containing all
     of the configuration variables.

   * *note get_path(): 1378. returns the configured path for a
     particular type of module: the standard library, site-specific
     modules, platform-specific modules, etc.

   * *note is_python_build(): 2dd. returns true if you’re running a
     binary from a Python source tree, and false otherwise.

Consult the *note sysconfig: db. documentation for more details and for
a complete list of functions.

The Distutils package and *note sysconfig: db. are now maintained by
Tarek Ziadé, who has also started a Distutils2 package (source
repository at ‘https://hg.python.org/distutils2/’) for developing a
next-generation version of Distutils.


File: python.info,  Node: ttk Themed Widgets for Tk,  Next: Updated module unittest,  Prev: New module sysconfig,  Up: New and Improved Modules

1.15.11.3 ttk: Themed Widgets for Tk
....................................

Tcl/Tk 8.5 includes a set of themed widgets that re-implement basic Tk
widgets but have a more customizable appearance and can therefore more
closely resemble the native platform’s widgets.  This widget set was
originally called Tile, but was renamed to Ttk (for “themed Tk”) on
being added to Tcl/Tck release 8.5.

To learn more, read the *note ttk: f9. module documentation.  You may
also wish to read the Tcl/Tk manual page describing the Ttk theme
engine, available at
‘https://www.tcl.tk/man/tcl8.5/TkCmd/ttk_intro.html’.  Some screenshots
of the Python/Ttk code in use are at
‘https://code.google.com/archive/p/python-ttk/wikis/Screenshots.wiki’.

The *note tkinter.ttk: f9. module was written by Guilherme Polo and
added in bpo-2983(1).  An alternate version called ‘Tile.py’, written by
Martin Franklin and maintained by Kevin Walzer, was proposed for
inclusion in bpo-2618(2), but the authors argued that Guilherme Polo’s
work was more comprehensive.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2983

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2618


File: python.info,  Node: Updated module unittest,  Next: Updated module ElementTree 1 3,  Prev: ttk Themed Widgets for Tk,  Up: New and Improved Modules

1.15.11.4 Updated module: unittest
..................................

The *note unittest: 106. module was greatly enhanced; many new features
were added.  Most of these features were implemented by Michael Foord,
unless otherwise noted.  The enhanced version of the module is
downloadable separately for use with Python versions 2.4 to 2.6,
packaged as the ‘unittest2’ package, from unittest2(1).

When used from the command line, the module can automatically discover
tests.  It’s not as fancy as py.test(2) or nose(3), but provides a
simple way to run tests kept within a set of package directories.  For
example, the following command will search the ‘test/’ subdirectory for
any importable test files named ‘test*.py’:

     python -m unittest discover -s test

Consult the *note unittest: 106. module documentation for more details.
(Developed in bpo-6001(4).)

The *note main(): 101e. function supports some other new options:

   * *note -b: 137c. or ‘--buffer’ will buffer the standard output and
     standard error streams during each test.  If the test passes, any
     resulting output will be discarded; on failure, the buffered output
     will be displayed.

   * *note -c: 137d. or ‘--catch’ will cause the control-C interrupt to
     be handled more gracefully.  Instead of interrupting the test
     process immediately, the currently running test will be completed
     and then the partial results up to the interruption will be
     reported.  If you’re impatient, a second press of control-C will
     cause an immediate interruption.

     This control-C handler tries to avoid causing problems when the
     code being tested or the tests being run have defined a signal
     handler of their own, by noticing that a signal handler was already
     set and calling it.  If this doesn’t work for you, there’s a *note
     removeHandler(): 137e. decorator that can be used to mark tests
     that should have the control-C handling disabled.

   * *note -f: 137f. or ‘--failfast’ makes test execution stop
     immediately when a test fails instead of continuing to execute
     further tests.  (Suggested by Cliff Dyer and implemented by Michael
     Foord; bpo-8074(5).)

The progress messages now show ‘x’ for expected failures and ‘u’ for
unexpected successes when run in verbose mode.  (Contributed by Benjamin
Peterson.)

Test cases can raise the *note SkipTest: 101f. exception to skip a test
(bpo-1034053(6)).

The error messages for *note assertEqual(): 52c, *note assertTrue():
52a, and *note assertFalse(): 52b. failures now provide more
information.  If you set the *note longMessage: 1380. attribute of your
*note TestCase: 451. classes to true, both the standard error message
and any additional message you provide will be printed for failures.
(Added by Michael Foord; bpo-5663(7).)

The *note assertRaises(): 530. method now returns a context handler when
called without providing a callable object to run.  For example, you can
write this:

     with self.assertRaises(KeyError):
         {}['foo']

(Implemented by Antoine Pitrou; bpo-4444(8).)

Module- and class-level setup and teardown fixtures are now supported.
Modules can contain *note setUpModule(): a5b. and *note
tearDownModule(): 1381. functions.  Classes can have *note setUpClass():
a5c. and *note tearDownClass(): 1382. methods that must be defined as
class methods (using ‘@classmethod’ or equivalent).  These functions and
methods are invoked when the test runner switches to a test case in a
different module or class.

The methods *note addCleanup(): a90. and *note doCleanups(): 1383. were
added.  ‘addCleanup()’ lets you add cleanup functions that will be
called unconditionally (after *note setUp(): 1384. if ‘setUp()’ fails,
otherwise after *note tearDown(): 1385.).  This allows for much simpler
resource allocation and deallocation during tests (bpo-5679(9)).

A number of new methods were added that provide more specialized tests.
Many of these methods were written by Google engineers for use in their
test suites; Gregory P. Smith, Michael Foord, and GvR worked on merging
them into Python’s version of *note unittest: 106.

   * *note assertIsNone(): 12d1. and *note assertIsNotNone(): 12d2. take
     one expression and verify that the result is or is not ‘None’.

   * *note assertIs(): 1386. and *note assertIsNot(): 1387. take two
     values and check whether the two values evaluate to the same object
     or not.  (Added by Michael Foord; bpo-2578(10).)

   * *note assertIsInstance(): 1388. and *note assertNotIsInstance():
     1389. check whether the resulting object is an instance of a
     particular class, or of one of a tuple of classes.  (Added by Georg
     Brandl; bpo-7031(11).)

   * *note assertGreater(): 138a, *note assertGreaterEqual(): 138b,
     *note assertLess(): 138c, and *note assertLessEqual(): 138d.
     compare two quantities.

   * *note assertMultiLineEqual(): 138e. compares two strings, and if
     they’re not equal, displays a helpful comparison that highlights
     the differences in the two strings.  This comparison is now used by
     default when Unicode strings are compared with *note assertEqual():
     52c.

   * *note assertRegexpMatches(): 531. and *note
     assertNotRegexpMatches(): 533. checks whether the first argument is
     a string matching or not matching the regular expression provided
     as the second argument (bpo-8038(12)).

   * *note assertRaisesRegexp(): 532. checks whether a particular
     exception is raised, and then also checks that the string
     representation of the exception matches the provided regular
     expression.

   * *note assertIn(): 138f. and *note assertNotIn(): 1390. tests
     whether 'first' is or is not in 'second'.

   * *note assertItemsEqual(): 1270. tests whether two provided
     sequences contain the same elements.

   * *note assertSetEqual(): 12cc. compares whether two sets are equal,
     and only reports the differences between the sets in case of error.

   * Similarly, *note assertListEqual(): 12ce. and *note
     assertTupleEqual(): 12cf. compare the specified types and explain
     any differences without necessarily printing their full values;
     these methods are now used by default when comparing lists and
     tuples using *note assertEqual(): 52c.  More generally, *note
     assertSequenceEqual(): 12d0. compares two sequences and can
     optionally check whether both sequences are of a particular type.

   * *note assertDictEqual(): 12cd. compares two dictionaries and
     reports the differences; it’s now used by default when you compare
     two dictionaries using *note assertEqual(): 52c.
     ‘assertDictContainsSubset()’ checks whether all of the key/value
     pairs in 'first' are found in 'second'.

   * *note assertAlmostEqual(): 52e. and *note assertNotAlmostEqual():
     52f. test whether 'first' and 'second' are approximately equal.
     This method can either round their difference to an optionally
     specified number of 'places' (the default is 7) and compare it to
     zero, or require the difference to be smaller than a supplied
     'delta' value.

   * *note loadTestsFromName(): 1391. properly honors the *note
     suiteClass: 1392. attribute of the *note TestLoader: 28e.  (Fixed
     by Mark Roddy; bpo-6866(13).)

   * A new hook lets you extend the *note assertEqual(): 52c. method to
     handle new data types.  The *note addTypeEqualityFunc(): 1393.
     method takes a type object and a function.  The function will be
     used when both of the objects being compared are of the specified
     type.  This function should compare the two objects and raise an
     exception if they don’t match; it’s a good idea for the function to
     provide additional information about why the two objects aren’t
     matching, much as the new sequence comparison methods do.

*note unittest.main(): 101e. now takes an optional ‘exit’ argument.  If
false, ‘main()’ doesn’t call *note sys.exit(): 1394, allowing ‘main()’
to be used from the interactive interpreter.  (Contributed by J. Pablo
Fernández; bpo-3379(14).)

*note TestResult: 11ab. has new *note startTestRun(): 1395. and *note
stopTestRun(): 1396. methods that are called immediately before and
after a test run.  (Contributed by Robert Collins; bpo-5728(15).)

With all these changes, the ‘unittest.py’ was becoming awkwardly large,
so the module was turned into a package and the code split into several
files (by Benjamin Peterson).  This doesn’t affect how the module is
imported or used.

See also
........

‘https://web.archive.org/web/20210619163128/http://www.voidspace.org.uk/python/articles/unittest2.shtml’

     Describes the new features, how to use them, and the rationale for
     various design decisions.  (By Michael Foord.)

   ---------- Footnotes ----------

   (1) https://pypi.org/project/unittest2/

   (2) https://pytest.org

   (3) https://nose.readthedocs.io/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=6001

   (5) https://bugs.python.org/issue?@action=redirect&bpo=8074

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1034053

   (7) https://bugs.python.org/issue?@action=redirect&bpo=5663

   (8) https://bugs.python.org/issue?@action=redirect&bpo=4444

   (9) https://bugs.python.org/issue?@action=redirect&bpo=5679

   (10) https://bugs.python.org/issue?@action=redirect&bpo=2578

   (11) https://bugs.python.org/issue?@action=redirect&bpo=7031

   (12) https://bugs.python.org/issue?@action=redirect&bpo=8038

   (13) https://bugs.python.org/issue?@action=redirect&bpo=6866

   (14) https://bugs.python.org/issue?@action=redirect&bpo=3379

   (15) https://bugs.python.org/issue?@action=redirect&bpo=5728


File: python.info,  Node: Updated module ElementTree 1 3,  Prev: Updated module unittest,  Up: New and Improved Modules

1.15.11.5 Updated module: ElementTree 1.3
.........................................

The version of the ElementTree library included with Python was updated
to version 1.3.  Some of the new features are:

   * The various parsing functions now take a 'parser' keyword argument
     giving an *note XMLParser: a62. instance that will be used.  This
     makes it possible to override the file’s internal encoding:

          p = ET.XMLParser(encoding='utf-8')
          t = ET.XML("""<root/>""", parser=p)

     Errors in parsing XML now raise a *note ParseError: 12be.
     exception, whose instances have a ‘position’ attribute containing a
     ('line', 'column') tuple giving the location of the problem.

   * ElementTree’s code for converting trees to a string has been
     significantly reworked, making it roughly twice as fast in many
     cases.  The *note ElementTree.write(): aaa. and ‘Element.write()’
     methods now have a 'method' parameter that can be “xml” (the
     default), “html”, or “text”.  HTML mode will output empty elements
     as ‘<empty></empty>’ instead of ‘<empty/>’, and text mode will skip
     over elements and only output the text chunks.  If you set the
     *note tag: 1399. attribute of an element to ‘None’ but leave its
     children in place, the element will be omitted when the tree is
     written out, so you don’t need to do more extensive rearrangement
     to remove a single element.

     Namespace handling has also been improved.  All ‘xmlns:<whatever>’
     declarations are now output on the root element, not scattered
     throughout the resulting XML. You can set the default namespace for
     a tree by setting the ‘default_namespace’ attribute and can
     register new prefixes with *note register_namespace(): 1217.  In
     XML mode, you can use the true/false 'xml_declaration' parameter to
     suppress the XML declaration.

   * New *note Element: 310. method: *note extend(): 1218. appends the
     items from a sequence to the element’s children.  Elements
     themselves behave like sequences, so it’s easy to move children
     from one element to another:

          from xml.etree import ElementTree as ET

          t = ET.XML("""<list>
            <item>1</item> <item>2</item>  <item>3</item>
          </list>""")
          new = ET.XML('<root/>')
          new.extend(t)

          # Outputs <root><item>1</item>...</root>
          print ET.tostring(new)

   * New *note Element: 310. method: *note iter(): 139a. yields the
     children of the element as a generator.  It’s also possible to
     write ‘for child in elem:’ to loop over an element’s children.  The
     existing method ‘getiterator()’ is now deprecated, as is
     ‘getchildren()’ which constructs and returns a list of children.

   * New *note Element: 310. method: *note itertext(): 121a. yields all
     chunks of text that are descendants of the element.  For example:

          t = ET.XML("""<list>
            <item>1</item> <item>2</item>  <item>3</item>
          </list>""")

          # Outputs ['\n  ', '1', ' ', '2', '  ', '3', '\n']
          print list(t.itertext())

   * Deprecated: using an element as a Boolean (i.e., ‘if elem:’) would
     return true if the element had any children, or false if there were
     no children.  This behaviour is confusing – ‘None’ is false, but so
     is a childless element?  – so it will now trigger a *note
     FutureWarning: 418.  In your code, you should be explicit: write
     ‘len(elem) != 0’ if you’re interested in the number of children, or
     ‘elem is not None’.

Fredrik Lundh develops ElementTree and produced the 1.3 version; you can
read his article describing 1.3 at
‘https://web.archive.org/web/20200703234532/http://effbot.org/zone/elementtree-13-intro.htm’.
Florent Xicluna updated the version included with Python, after
discussions on python-dev and in bpo-6472(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=6472


File: python.info,  Node: Build and C API Changes<8>,  Next: Other Changes and Fixes,  Prev: New and Improved Modules,  Up: What’s New in Python 2 7

1.15.12 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * The latest release of the GNU Debugger, GDB 7, can be scripted
     using Python(1).  When you begin debugging an executable program P,
     GDB will look for a file named ‘P-gdb.py’ and automatically read
     it.  Dave Malcolm contributed a ‘python-gdb.py’ that adds a number
     of commands useful when debugging Python itself.  For example,
     ‘py-up’ and ‘py-down’ go up or down one Python stack frame, which
     usually corresponds to several C stack frames.  ‘py-print’ prints
     the value of a Python variable, and ‘py-bt’ prints the Python stack
     trace.  (Added as a result of bpo-8032(2).)

   * If you use the ‘.gdbinit’ file provided with Python, the “pyo”
     macro in the 2.7 version now works correctly when the thread being
     debugged doesn’t hold the GIL; the macro now acquires it before
     printing.  (Contributed by Victor Stinner; bpo-3632(3).)

   * *note Py_AddPendingCall(): 98b. is now thread-safe, letting any
     worker thread submit notifications to the main Python thread.  This
     is particularly useful for asynchronous IO operations.
     (Contributed by Kristján Valur Jónsson; bpo-4293(4).)

   * New function: *note PyCode_NewEmpty(): 139c. creates an empty code
     object; only the filename, function name, and first line number are
     required.  This is useful for extension modules that are attempting
     to construct a more useful traceback stack.  Previously such
     extensions needed to call ‘PyCode_New()’, which had many more
     arguments.  (Added by Jeffrey Yasskin.)

   * New function: *note PyErr_NewExceptionWithDoc(): 12af. creates a
     new exception class, just as the existing *note
     PyErr_NewException(): 12b0. does, but takes an extra ‘char *’
     argument containing the docstring for the new exception class.
     (Added by ‘lekma’ on the Python bug tracker; bpo-7033(5).)

   * New function: *note PyFrame_GetLineNumber(): 78e. takes a frame
     object and returns the line number that the frame is currently
     executing.  Previously code would need to get the index of the
     bytecode instruction currently executing, and then look up the line
     number corresponding to that address.  (Added by Jeffrey Yasskin.)

   * New functions: *note PyLong_AsLongAndOverflow(): 12ad. and *note
     PyLong_AsLongLongAndOverflow(): 12ac. approximates a Python long
     integer as a C long or long long.  If the number is too large to
     fit into the output type, an 'overflow' flag is set and returned to
     the caller.  (Contributed by Case Van Horsen; bpo-7528(6) and
     bpo-7767(7).)

   * New function: stemming from the rewrite of string-to-float
     conversion, a new *note PyOS_string_to_double(): 12dc. function was
     added.  The old ‘PyOS_ascii_strtod()’ and ‘PyOS_ascii_atof()’
     functions are now deprecated.

   * New function: ‘PySys_SetArgvEx()’ sets the value of ‘sys.argv’ and
     can optionally update ‘sys.path’ to include the directory
     containing the script named by ‘sys.argv[0]’ depending on the value
     of an 'updatepath' parameter.

     This function was added to close a security hole for applications
     that embed Python.  The old function, ‘PySys_SetArgv()’, would
     always update ‘sys.path’, and sometimes it would add the current
     directory.  This meant that, if you ran an application embedding
     Python in a directory controlled by someone else, attackers could
     put a Trojan-horse module in the directory (say, a file named
     ‘os.py’) that your application would then import and run.

     If you maintain a C/C++ application that embeds Python, check
     whether you’re calling ‘PySys_SetArgv()’ and carefully consider
     whether the application should be using ‘PySys_SetArgvEx()’ with
     'updatepath' set to false.

     Security issue reported as CVE 2008-5983(8); discussed in
     bpo-5753(9), and fixed by Antoine Pitrou.

   * New macros: the Python header files now define the following
     macros: *note Py_ISALNUM: 139d, *note Py_ISALPHA: 139e, *note
     Py_ISDIGIT: 139f, *note Py_ISLOWER: 13a0, *note Py_ISSPACE: 13a1,
     *note Py_ISUPPER: 13a2, *note Py_ISXDIGIT: 13a3, *note Py_TOLOWER:
     13a4, and *note Py_TOUPPER: 13a5.  All of these functions are
     analogous to the C standard macros for classifying characters, but
     ignore the current locale setting, because in several places Python
     needs to analyze characters in a locale-independent way.  (Added by
     Eric Smith; bpo-5793(10).)

   * Removed function: ‘PyEval_CallObject()’ is now only available as a
     macro.  A function version was being kept around to preserve ABI
     linking compatibility, but that was in 1997; it can certainly be
     deleted by now.  (Removed by Antoine Pitrou; bpo-8276(11).)

   * New format codes: the ‘PyString_FromFormat()’,
     ‘PyString_FromFormatV()’, and *note PyErr_Format(): ee5. functions
     now accept ‘%lld’ and ‘%llu’ format codes for displaying C’s long
     long types.  (Contributed by Mark Dickinson; bpo-7228(12).)

   * The complicated interaction between threads and process forking has
     been changed.  Previously, the child process created by *note
     os.fork(): 197. might fail because the child is created with only a
     single thread running, the thread performing the ‘os.fork()’.  If
     other threads were holding a lock, such as Python’s import lock,
     when the fork was performed, the lock would still be marked as
     “held” in the new process.  But in the child process nothing would
     ever release the lock, since the other threads weren’t replicated,
     and the child process would no longer be able to perform imports.

     Python 2.7 acquires the import lock before performing an *note
     os.fork(): 197, and will also clean up any locks created using the
     *note threading: ed. module.  C extension modules that have
     internal locks, or that call ‘fork()’ themselves, will not benefit
     from this clean-up.

     (Fixed by Thomas Wouters; bpo-1590864(13).)

   * The *note Py_Finalize(): 13a6. function now calls the internal
     ‘threading._shutdown()’ function; this prevents some exceptions
     from being raised when an interpreter shuts down.  (Patch by Adam
     Olsen; bpo-1722344(14).)

   * When using the *note PyMemberDef: 552. structure to define
     attributes of a type, Python will no longer let you try to delete
     or set a ‘T_STRING_INPLACE’ attribute.

   * Global symbols defined by the *note ctypes: 2a. module are now
     prefixed with ‘Py’, or with ‘_ctypes’.  (Implemented by Thomas
     Heller; bpo-3102(15).)

   * New configure option: the ‘--with-system-expat’ switch allows
     building the *note pyexpat: 126. module to use the system Expat
     library.  (Contributed by Arfrever Frehtes Taifersar Arahesis;
     bpo-7609(16).)

   * New configure option: the ‘--with-valgrind’ option will now disable
     the pymalloc allocator, which is difficult for the Valgrind
     memory-error detector to analyze correctly.  Valgrind will
     therefore be better at detecting memory leaks and overruns.
     (Contributed by James Henstridge; bpo-2422(17).)

   * New configure option: you can now supply an empty string to
     ‘--with-dbmliborder=’ in order to disable all of the various DBM
     modules.  (Added by Arfrever Frehtes Taifersar Arahesis;
     bpo-6491(18).)

   * The ‘configure’ script now checks for floating-point rounding bugs
     on certain 32-bit Intel chips and defines a ‘X87_DOUBLE_ROUNDING’
     preprocessor definition.  No code currently uses this definition,
     but it’s available if anyone wishes to use it.  (Added by Mark
     Dickinson; bpo-2937(19).)

     ‘configure’ also now sets a ‘LDCXXSHARED’ Makefile variable for
     supporting C++ linking.  (Contributed by Arfrever Frehtes Taifersar
     Arahesis; bpo-1222585(20).)

   * The build process now creates the necessary files for pkg-config
     support.  (Contributed by Clinton Roy; bpo-3585(21).)

   * The build process now supports Subversion 1.7.  (Contributed by
     Arfrever Frehtes Taifersar Arahesis; bpo-6094(22).)

* Menu:

* Capsules::
* Port-Specific Changes; Windows: Port-Specific Changes Windows.
* Port-Specific Changes; Mac OS X: Port-Specific Changes Mac OS X.
* Port-Specific Changes; FreeBSD: Port-Specific Changes FreeBSD.

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20110715084810/http://sourceware.org/gdb/current/onlinedocs/gdb/Python.html

   (2) https://bugs.python.org/issue?@action=redirect&bpo=8032

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3632

   (4) https://bugs.python.org/issue?@action=redirect&bpo=4293

   (5) https://bugs.python.org/issue?@action=redirect&bpo=7033

   (6) https://bugs.python.org/issue?@action=redirect&bpo=7528

   (7) https://bugs.python.org/issue?@action=redirect&bpo=7767

   (8) https://www.cve.org/CVERecord?id=CVE-2008-5983

   (9) https://bugs.python.org/issue?@action=redirect&bpo=5753

   (10) https://bugs.python.org/issue?@action=redirect&bpo=5793

   (11) https://bugs.python.org/issue?@action=redirect&bpo=8276

   (12) https://bugs.python.org/issue?@action=redirect&bpo=7228

   (13) https://bugs.python.org/issue?@action=redirect&bpo=1590864

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1722344

   (15) https://bugs.python.org/issue?@action=redirect&bpo=3102

   (16) https://bugs.python.org/issue?@action=redirect&bpo=7609

   (17) https://bugs.python.org/issue?@action=redirect&bpo=2422

   (18) https://bugs.python.org/issue?@action=redirect&bpo=6491

   (19) https://bugs.python.org/issue?@action=redirect&bpo=2937

   (20) https://bugs.python.org/issue?@action=redirect&bpo=1222585

   (21) https://bugs.python.org/issue?@action=redirect&bpo=3585

   (22) https://bugs.python.org/issue?@action=redirect&bpo=6094


File: python.info,  Node: Capsules,  Next: Port-Specific Changes Windows,  Up: Build and C API Changes<8>

1.15.12.1 Capsules
..................

Python 3.1 adds a new C datatype, *note PyCapsule: 12b9, for providing a
C API to an extension module.  A capsule is essentially the holder of a
C ‘void *’ pointer, and is made available as a module attribute; for
example, the *note socket: cc. module’s API is exposed as ‘socket.CAPI’,
and *note unicodedata: 105. exposes ‘ucnhash_CAPI’.  Other extensions
can import the module, access its dictionary to get the capsule object,
and then get the ‘void *’ pointer, which will usually point to an array
of pointers to the module’s various API functions.

There is an existing data type already used for this, ‘PyCObject’, but
it doesn’t provide type safety.  Evil code written in pure Python could
cause a segmentation fault by taking a ‘PyCObject’ from module A and
somehow substituting it for the ‘PyCObject’ in module B. Capsules know
their own name, and getting the pointer requires providing the name:

     void *vtable;

     if (!PyCapsule_IsValid(capsule, "mymodule.CAPI") {
             PyErr_SetString(PyExc_ValueError, "argument type invalid");
             return NULL;
     }

     vtable = PyCapsule_GetPointer(capsule, "mymodule.CAPI");

You are assured that ‘vtable’ points to whatever you’re expecting.  If a
different capsule was passed in, *note PyCapsule_IsValid(): 13a9. would
detect the mismatched name and return false.  Refer to *note Providing a
C API for an Extension Module: 13aa. for more information on using these
objects.

Python 2.7 now uses capsules internally to provide various
extension-module APIs, but the ‘PyCObject_AsVoidPtr()’ was modified to
handle capsules, preserving compile-time compatibility with the
‘PyCObject’ interface.  Use of ‘PyCObject_AsVoidPtr()’ will signal a
*note PendingDeprecationWarning: 8d1, which is silent by default.

Implemented in Python 3.1 and backported to 2.7 by Larry Hastings;
discussed in bpo-5630(1).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5630


File: python.info,  Node: Port-Specific Changes Windows,  Next: Port-Specific Changes Mac OS X,  Prev: Capsules,  Up: Build and C API Changes<8>

1.15.12.2 Port-Specific Changes: Windows
........................................

   * The *note msvcrt: 93. module now contains some constants from the
     ‘crtassem.h’ header file: *note CRT_ASSEMBLY_VERSION: 13ac, *note
     VC_ASSEMBLY_PUBLICKEYTOKEN: 13ad, and *note
     LIBRARIES_ASSEMBLY_NAME_PREFIX: 13ae.  (Contributed by David
     Cournapeau; bpo-4365(1).)

   * The *note _winreg: 116. module for accessing the registry now
     implements the *note CreateKeyEx(): 13af. and *note DeleteKeyEx():
     13b0. functions, extended versions of previously supported
     functions that take several extra arguments.  The *note
     DisableReflectionKey(): 13b1, *note EnableReflectionKey(): 13b2,
     and *note QueryReflectionKey(): 13b3. were also tested and
     documented.  (Implemented by Brian Curtin: bpo-7347(2).)

   * The new ‘_beginthreadex()’ API is used to start threads, and the
     native thread-local storage functions are now used.  (Contributed
     by Kristján Valur Jónsson; bpo-3582(3).)

   * The *note os.kill(): 13b4. function now works on Windows.  The
     signal value can be the constants *note CTRL_C_EVENT: 13b5, *note
     CTRL_BREAK_EVENT: 13b6, or any integer.  The first two constants
     will send ‘Control’-‘C’ and ‘Control’-‘Break’ keystroke events to
     subprocesses; any other value will use the ‘TerminateProcess()’
     API.  (Contributed by Miki Tebeka; bpo-1220212(4).)

   * The *note os.listdir(): 113e. function now correctly fails for an
     empty path.  (Fixed by Hirokazu Yamamoto; bpo-5913(5).)

   * The *note mimetypes: 8f. module will now read the MIME database
     from the Windows registry when initializing.  (Patch by Gabriel
     Genellina; bpo-4969(6).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4365

   (2) https://bugs.python.org/issue?@action=redirect&bpo=7347

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3582

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1220212

   (5) https://bugs.python.org/issue?@action=redirect&bpo=5913

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4969


File: python.info,  Node: Port-Specific Changes Mac OS X,  Next: Port-Specific Changes FreeBSD,  Prev: Port-Specific Changes Windows,  Up: Build and C API Changes<8>

1.15.12.3 Port-Specific Changes: Mac OS X
.........................................

   * The path ‘/Library/Python/2.7/site-packages’ is now appended to
     ‘sys.path’, in order to share added packages between the system
     installation and a user-installed copy of the same version.
     (Changed by Ronald Oussoren; bpo-4865(1).)

     Changed in version 2.7.13: As of 2.7.13, this change was removed.
     ‘/Library/Python/2.7/site-packages’, the site-packages directory
     used by the Apple-supplied system Python 2.7 is no longer appended
     to ‘sys.path’ for user-installed Pythons such as from the
     python.org installers.  As of macOS 10.12, Apple changed how the
     system site-packages directory is configured, which could cause
     installation of pip components, like setuptools, to fail.  Packages
     installed for the system Python will no longer be shared with
     user-installed Pythons.  (bpo-28440(2))

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=4865

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28440


File: python.info,  Node: Port-Specific Changes FreeBSD,  Prev: Port-Specific Changes Mac OS X,  Up: Build and C API Changes<8>

1.15.12.4 Port-Specific Changes: FreeBSD
........................................

   * FreeBSD 7.1’s ‘SO_SETFIB’ constant, used with the *note socket():
     dcf. methods *note getsockopt(): cfb./*note setsockopt(): cfc. to
     select an alternate routing table, is now available in the *note
     socket: cc. module.  (Added by Kyle VanderBeek; bpo-8235(1).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=8235


File: python.info,  Node: Other Changes and Fixes,  Next: Porting to Python 2 7,  Prev: Build and C API Changes<8>,  Up: What’s New in Python 2 7

1.15.13 Other Changes and Fixes
-------------------------------

   * Two benchmark scripts, ‘iobench’ and ‘ccbench’, were added to the
     ‘Tools’ directory.  ‘iobench’ measures the speed of the built-in
     file I/O objects returned by *note open(): 51f. while performing
     various operations, and ‘ccbench’ is a concurrency benchmark that
     tries to measure computing throughput, thread switching latency,
     and IO processing bandwidth when performing several tasks using a
     varying number of threads.

   * The ‘Tools/i18n/msgfmt.py’ script now understands plural forms in
     ‘.po’ files.  (Fixed by Martin von Löwis; bpo-5464(1).)

   * When importing a module from a ‘.pyc’ or ‘.pyo’ file with an
     existing ‘.py’ counterpart, the *note co_filename: 13ba. attributes
     of the resulting code objects are overwritten when the original
     filename is obsolete.  This can happen if the file has been
     renamed, moved, or is accessed through different paths.  (Patch by
     Ziga Seilnacht and Jean-Paul Calderone; bpo-1180193(2).)

   * The ‘regrtest.py’ script now takes a ‘--randseed=’ switch that
     takes an integer that will be used as the random seed for the ‘-r’
     option that executes tests in random order.  The ‘-r’ option also
     reports the seed that was used (Added by Collin Winter.)

   * Another ‘regrtest.py’ switch is ‘-j’, which takes an integer
     specifying how many tests run in parallel.  This allows reducing
     the total runtime on multi-core machines.  This option is
     compatible with several other options, including the ‘-R’ switch
     which is known to produce long runtimes.  (Added by Antoine Pitrou,
     bpo-6152(3).)  This can also be used with a new ‘-F’ switch that
     runs selected tests in a loop until they fail.  (Added by Antoine
     Pitrou; bpo-7312(4).)

   * When executed as a script, the ‘py_compile.py’ module now accepts
     ‘'-'’ as an argument, which will read standard input for the list
     of filenames to be compiled.  (Contributed by Piotr Ożarowski;
     bpo-8233(5).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5464

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1180193

   (3) https://bugs.python.org/issue?@action=redirect&bpo=6152

   (4) https://bugs.python.org/issue?@action=redirect&bpo=7312

   (5) https://bugs.python.org/issue?@action=redirect&bpo=8233


File: python.info,  Node: Porting to Python 2 7,  Next: New Features Added to Python 2 7 Maintenance Releases,  Prev: Other Changes and Fixes,  Up: What’s New in Python 2 7

1.15.14 Porting to Python 2.7
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code:

   * The *note range(): 94d. function processes its arguments more
     consistently; it will now call *note __int__(): 71f. on non-float,
     non-integer arguments that are supplied to it.  (Fixed by Alexander
     Belopolsky; bpo-1533(1).)

   * The string *note format(): 622. method changed the default
     precision used for floating-point and complex numbers from 6
     decimal places to 12, which matches the precision used by *note
     str(): 44f.  (Changed by Eric Smith; bpo-5920(2).)

   * Because of an optimization for the *note with: 5d5. statement, the
     special methods *note __enter__(): 5cb. and *note __exit__(): 1349.
     must belong to the object’s type, and cannot be directly attached
     to the object’s instance.  This affects new-style classes (derived
     from *note object: a9b.) and C extension types.  (bpo-6101(3).)

   * Due to a bug in Python 2.6, the 'exc_value' parameter to *note
     __exit__(): 1349. methods was often the string representation of
     the exception, not an instance.  This was fixed in 2.7, so
     'exc_value' will be an instance as expected.  (Fixed by Florent
     Xicluna; bpo-7853(4).)

   * When a restricted set of attributes were set using ‘__slots__’,
     deleting an unset attribute would not raise *note AttributeError:
     34e. as you would expect.  Fixed by Benjamin Peterson;
     bpo-7604(5).)

In the standard library:

   * Operations with *note datetime: 1cc. instances that resulted in a
     year falling outside the supported range didn’t always raise *note
     OverflowError: 888.  Such errors are now checked more carefully and
     will now raise the exception.  (Reported by Mark Leander, patch by
     Anand B. Pillai and Alexander Belopolsky; bpo-7150(6).)

   * When using *note Decimal: 29d. instances with a string’s *note
     format(): 622. method, the default alignment was previously
     left-alignment.  This has been changed to right-alignment, which
     might change the output of your programs.  (Changed by Mark
     Dickinson; bpo-6857(7).)

     Comparisons involving a signaling NaN value (or ‘sNAN’) now signal
     *note InvalidOperation: 10ec. instead of silently returning a true
     or false value depending on the comparison operator.  Quiet NaN
     values (or ‘NaN’) are now hashable.  (Fixed by Mark Dickinson;
     bpo-7279(8).)

   * The *note xml.etree.ElementTree: 125. library no longer escapes
     ampersands and angle brackets when outputting an XML processing
     instruction (which looks like ‘<?xml-stylesheet href="#style1"?>’)
     or comment (which looks like ‘<!-- comment -->’).  (Patch by Neil
     Muller; bpo-2746(9).)

   * The ‘readline()’ method of *note StringIO: f5e. objects now does
     nothing when a negative length is requested, as other file-like
     objects do.  (bpo-7348(10)).

   * The *note syslog: dc. module will now use the value of
     ‘sys.argv[0]’ as the identifier instead of the previous default
     value of ‘'python'’.  (Changed by Sean Reifschneider;
     bpo-8451(11).)

   * The *note tarfile: de. module’s default error handling has changed,
     to no longer suppress fatal errors.  The default error level was
     previously 0, which meant that errors would only result in a
     message being written to the debug log, but because the debug log
     is not activated by default, these errors go unnoticed.  The
     default error level is now 1, which raises an exception if there’s
     an error.  (Changed by Lars Gustäbel; bpo-7357(12).)

   * The *note urlparse: 10a. module’s *note urlsplit(): d67. now
     handles unknown URL schemes in a fashion compliant with RFC
     3986(13): if the URL is of the form ‘"<something>://..."’, the text
     before the ‘://’ is treated as the scheme, even if it’s a made-up
     scheme that the module doesn’t know about.  This change may break
     code that worked around the old behaviour.  For example, Python
     2.6.4 or 2.5 will return the following:

          >>> import urlparse
          >>> urlparse.urlsplit('invented://host/filename?query')
          ('invented', '', '//host/filename?query', '', '')

     Python 2.7 (and Python 2.6.5) will return:

          >>> import urlparse
          >>> urlparse.urlsplit('invented://host/filename?query')
          ('invented', 'host', '/filename?query', '', '')

     (Python 2.7 actually produces slightly different output, since it
     returns a named tuple instead of a standard tuple.)

For C extensions:

   * C extensions that use integer format codes with the ‘PyArg_Parse*’
     family of functions will now raise a *note TypeError: 2c3.
     exception instead of triggering a *note DeprecationWarning: 1a5.
     (bpo-5080(14)).

   * Use the new *note PyOS_string_to_double(): 12dc. function instead
     of the old ‘PyOS_ascii_strtod()’ and ‘PyOS_ascii_atof()’ functions,
     which are now deprecated.

For applications that embed Python:

   * The ‘PySys_SetArgvEx()’ function was added, letting applications
     close a security hole when the existing ‘PySys_SetArgv()’ function
     was used.  Check whether you’re calling ‘PySys_SetArgv()’ and
     carefully consider whether the application should be using
     ‘PySys_SetArgvEx()’ with 'updatepath' set to false.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1533

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5920

   (3) https://bugs.python.org/issue?@action=redirect&bpo=6101

   (4) https://bugs.python.org/issue?@action=redirect&bpo=7853

   (5) https://bugs.python.org/issue?@action=redirect&bpo=7604

   (6) https://bugs.python.org/issue?@action=redirect&bpo=7150

   (7) https://bugs.python.org/issue?@action=redirect&bpo=6857

   (8) https://bugs.python.org/issue?@action=redirect&bpo=7279

   (9) https://bugs.python.org/issue?@action=redirect&bpo=2746

   (10) https://bugs.python.org/issue?@action=redirect&bpo=7348

   (11) https://bugs.python.org/issue?@action=redirect&bpo=8451

   (12) https://bugs.python.org/issue?@action=redirect&bpo=7357

   (13) https://datatracker.ietf.org/doc/html/rfc3986.html

   (14) https://bugs.python.org/issue?@action=redirect&bpo=5080


File: python.info,  Node: New Features Added to Python 2 7 Maintenance Releases,  Next: Acknowledgements,  Prev: Porting to Python 2 7,  Up: What’s New in Python 2 7

1.15.15 New Features Added to Python 2.7 Maintenance Releases
-------------------------------------------------------------

New features may be added to Python 2.7 maintenance releases when the
situation genuinely calls for it.  Any such additions must go through
the Python Enhancement Proposal process, and make a compelling case for
why they can’t be adequately addressed by either adding the new feature
solely to Python 3, or else by publishing it on the Python Package
Index.

In addition to the specific proposals listed below, there is a general
exemption allowing new ‘-3’ warnings to be added in any Python 2.7
maintenance release.

* Menu:

* Two new environment variables for debug mode::
* PEP 434; IDLE Enhancement Exception for All Branches: PEP 434 IDLE Enhancement Exception for All Branches.
* PEP 466; Network Security Enhancements for Python 2.7: PEP 466 Network Security Enhancements for Python 2 7.
* PEP 477; Backport ensurepip (PEP 453) to Python 2.7: PEP 477 Backport ensurepip PEP 453 to Python 2 7.
* PEP 476; Enabling certificate verification by default for stdlib http clients: PEP 476 Enabling certificate verification by default for stdlib http clients<2>.
* PEP 493; HTTPS verification migration tools for Python 2.7: PEP 493 HTTPS verification migration tools for Python 2 7.
* New make regen-all build target: New make regen-all build target<3>.
* Removal of make touch build target: Removal of make touch build target<3>.


File: python.info,  Node: Two new environment variables for debug mode,  Next: PEP 434 IDLE Enhancement Exception for All Branches,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.1 Two new environment variables for debug mode
......................................................

In debug mode, the ‘[xxx refs]’ statistic is not written by default, the
‘PYTHONSHOWREFCOUNT’ environment variable now must also be set.
(Contributed by Victor Stinner; bpo-31733(1).)

When Python is compiled with ‘COUNT_ALLOC’ defined, allocation counts
are no longer dumped by default anymore: the ‘PYTHONSHOWALLOCCOUNT’
environment variable must now also be set.  Moreover, allocation counts
are now dumped into stderr, rather than stdout.  (Contributed by Victor
Stinner; bpo-31692(2).)

Added in version 2.7.15.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31733

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31692


File: python.info,  Node: PEP 434 IDLE Enhancement Exception for All Branches,  Next: PEP 466 Network Security Enhancements for Python 2 7,  Prev: Two new environment variables for debug mode,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.2 PEP 434: IDLE Enhancement Exception for All Branches
..............................................................

PEP 434(1) describes a general exemption for changes made to the IDLE
development environment shipped along with Python.  This exemption makes
it possible for the IDLE developers to provide a more consistent user
experience across all supported versions of Python 2 and 3.

For details of any IDLE changes, refer to the NEWS file for the specific
release.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0434/


File: python.info,  Node: PEP 466 Network Security Enhancements for Python 2 7,  Next: PEP 477 Backport ensurepip PEP 453 to Python 2 7,  Prev: PEP 434 IDLE Enhancement Exception for All Branches,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.3 PEP 466: Network Security Enhancements for Python 2.7
...............................................................

PEP 466(1) describes a number of network security enhancement proposals
that have been approved for inclusion in Python 2.7 maintenance
releases, with the first of those changes appearing in the Python 2.7.7
release.

PEP 466(2) related features added in Python 2.7.7:

   * *note hmac.compare_digest(): 110d. was backported from Python 3 to
     make a timing attack resistant comparison operation available to
     Python 2 applications.  (Contributed by Alex Gaynor; bpo-21306(3).)

   * OpenSSL 1.0.1g was upgraded in the official Windows installers
     published on python.org.  (Contributed by Zachary Ware;
     bpo-21462(4).)

PEP 466(5) related features added in Python 2.7.8:

   * *note hashlib.pbkdf2_hmac(): 512. was backported from Python 3 to
     make a hashing algorithm suitable for secure password storage
     broadly available to Python 2 applications.  (Contributed by Alex
     Gaynor; bpo-21304(6).)

   * OpenSSL 1.0.1h was upgraded for the official Windows installers
     published on python.org.  (Contributed by Zachary Ware in
     bpo-21671(7) for CVE 2014-0224(8).)

PEP 466(9) related features added in Python 2.7.9:

   * Most of Python 3.4’s *note ssl: d0. module was backported.  This
     means ‘ssl’ now supports Server Name Indication, TLS1.x settings,
     access to the platform certificate store, the *note SSLContext:
     294. class, and other features.  (Contributed by Alex Gaynor and
     David Reid; bpo-21308(10).)

     Refer to the “Version added: 2.7.9” notes in the module
     documentation for specific details.

   * *note os.urandom(): 526. was changed to cache a file descriptor to
     ‘/dev/urandom’ instead of reopening ‘/dev/urandom’ on every call.
     (Contributed by Alex Gaynor; bpo-21305(11).)

   * *note hashlib.algorithms_guaranteed: 13c0. and *note
     hashlib.algorithms_available: 13c1. were backported from Python 3
     to make it easier for Python 2 applications to select the strongest
     available hash algorithm.  (Contributed by Alex Gaynor in
     bpo-21307(12))

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0466/

   (2) https://peps.python.org/pep-0466/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21306

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21462

   (5) https://peps.python.org/pep-0466/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21304

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21671

   (8) https://www.cve.org/CVERecord?id=CVE-2014-0224

   (9) https://peps.python.org/pep-0466/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21308

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21305

   (12) https://bugs.python.org/issue?@action=redirect&bpo=21307


File: python.info,  Node: PEP 477 Backport ensurepip PEP 453 to Python 2 7,  Next: PEP 476 Enabling certificate verification by default for stdlib http clients<2>,  Prev: PEP 466 Network Security Enhancements for Python 2 7,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.4 PEP 477: Backport ensurepip (PEP 453) to Python 2.7
.............................................................

PEP 477(1) approves the inclusion of the PEP 453(2) ensurepip module and
the improved documentation that was enabled by it in the Python 2.7
maintenance releases, appearing first in the Python 2.7.9 release.

* Menu:

* Bootstrapping pip By Default: Bootstrapping pip By Default<2>.
* Documentation Changes: Documentation Changes<2>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0477/

   (2) https://peps.python.org/pep-0453/


File: python.info,  Node: Bootstrapping pip By Default<2>,  Next: Documentation Changes<2>,  Up: PEP 477 Backport ensurepip PEP 453 to Python 2 7

1.15.15.5 Bootstrapping pip By Default
......................................

The new *note ensurepip: 55. module (defined in PEP 453(1)) provides a
standard cross-platform mechanism to bootstrap the pip installer into
Python installations.  The version of ‘pip’ included with Python 2.7.9
is ‘pip’ 1.5.6, and future 2.7.x maintenance releases will update the
bundled version to the latest version of ‘pip’ that is available at the
time of creating the release candidate.

By default, the commands ‘pip’, ‘pipX’ and ‘pipX.Y’ will be installed on
all platforms (where X.Y stands for the version of the Python
installation), along with the ‘pip’ Python package and its dependencies.

For CPython *note source builds on POSIX systems: f2a, the ‘make
install’ and ‘make altinstall’ commands do not bootstrap ‘pip’ by
default.  This behaviour can be controlled through configure options,
and overridden through Makefile options.

On Windows and Mac OS X, the CPython installers now default to
installing ‘pip’ along with CPython itself (users may opt out of
installing it during the installation process).  Window users will need
to opt in to the automatic ‘PATH’ modifications to have ‘pip’ available
from the command line by default, otherwise it can still be accessed
through the Python launcher for Windows as ‘py -m pip’.

As discussed in the PEP(2), platform packagers may choose not to install
these commands by default, as long as, when invoked, they provide clear
and simple directions on how to install them on that platform (usually
using the system package manager).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0453/

   (2) 
https://peps.python.org/pep-0477/#disabling-ensurepip-by-downstream-distributors


File: python.info,  Node: Documentation Changes<2>,  Prev: Bootstrapping pip By Default<2>,  Up: PEP 477 Backport ensurepip PEP 453 to Python 2 7

1.15.15.6 Documentation Changes
...............................

As part of this change, the *note Installing Python modules: f2c. and
distributing-index sections of the documentation have been completely
redesigned as short getting started and FAQ documents.  Most packaging
documentation has now been moved out to the Python Packaging Authority
maintained Python Packaging User Guide(1) and the documentation of the
individual projects.

However, as this migration is currently still incomplete, the legacy
versions of those guides remaining available as *note Building C and C++
Extensions with setuptools: f2d. and *note Building C and C++ Extensions
with setuptools: f2e.

See also
........

PEP 453(2) – Explicit bootstrapping of pip in Python installations

     PEP written by Donald Stufft and Nick Coghlan, implemented by
     Donald Stufft, Nick Coghlan, Martin von Löwis and Ned Deily.

   ---------- Footnotes ----------

   (1) https://packaging.python.org

   (2) https://peps.python.org/pep-0453/


File: python.info,  Node: PEP 476 Enabling certificate verification by default for stdlib http clients<2>,  Next: PEP 493 HTTPS verification migration tools for Python 2 7,  Prev: PEP 477 Backport ensurepip PEP 453 to Python 2 7,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.7 PEP 476: Enabling certificate verification by default for stdlib http clients
.......................................................................................

PEP 476(1) updated *note httplib: 6e. and modules which use it, such as
*note urllib2: 10b. and *note xmlrpclib: 12e, to now verify that the
server presents a certificate which is signed by a Certificate Authority
in the platform trust store and whose hostname matches the hostname
being requested by default, significantly improving security for many
applications.  This change was made in the Python 2.7.9 release.

For applications which require the old previous behavior, they can pass
an alternate context:

     import urllib2
     import ssl

     # This disables all verification
     context = ssl._create_unverified_context()

     # This allows using a specific certificate for the host, which doesn't need
     # to be in the trust store
     context = ssl.create_default_context(cafile="/path/to/file.crt")

     urllib2.urlopen("https://invalid-cert", context=context)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0476/


File: python.info,  Node: PEP 493 HTTPS verification migration tools for Python 2 7,  Next: New make regen-all build target<3>,  Prev: PEP 476 Enabling certificate verification by default for stdlib http clients<2>,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.8 PEP 493: HTTPS verification migration tools for Python 2.7
....................................................................

PEP 493(1) provides additional migration tools to support a more
incremental infrastructure upgrade process for environments containing
applications and services relying on the historically permissive
processing of server certificates when establishing client HTTPS
connections.  These additions were made in the Python 2.7.12 release.

These tools are intended for use in cases where affected applications
and services can’t be modified to explicitly pass a more permissive SSL
context when establishing the connection.

For applications and services which can’t be modified at all, the new
‘PYTHONHTTPSVERIFY’ environment variable may be set to ‘0’ to revert an
entire Python process back to the default permissive behaviour of Python
2.7.8 and earlier.

For cases where the connection establishment code can’t be modified, but
the overall application can be, the new
‘ssl._https_verify_certificates()’ function can be used to adjust the
default behaviour at runtime.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0493/


File: python.info,  Node: New make regen-all build target<3>,  Next: Removal of make touch build target<3>,  Prev: PEP 493 HTTPS verification migration tools for Python 2 7,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.9 New ‘make regen-all’ build target
...........................................

To simplify cross-compilation, and to ensure that CPython can reliably
be compiled without requiring an existing version of Python to already
be available, the autotools-based build system no longer attempts to
implicitly recompile generated files based on file modification times.

Instead, a new ‘make regen-all’ command has been added to force
regeneration of these files when desired (e.g.  after an initial version
of Python has already been built based on the pregenerated versions).

More selective regeneration targets are also defined - see
Makefile.pre.in(1) for details.

(Contributed by Victor Stinner in bpo-23404(2).)

Added in version 2.7.14.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Makefile.pre.in

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: Removal of make touch build target<3>,  Prev: New make regen-all build target<3>,  Up: New Features Added to Python 2 7 Maintenance Releases

1.15.15.10 Removal of ‘make touch’ build target
...............................................

The ‘make touch’ build target previously used to request implicit
regeneration of generated files by updating their modification times has
been removed.

It has been replaced by the new ‘make regen-all’ target.

(Contributed by Victor Stinner in bpo-23404(1).)

Changed in version 2.7.14.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23404


File: python.info,  Node: Acknowledgements,  Prev: New Features Added to Python 2 7 Maintenance Releases,  Up: What’s New in Python 2 7

1.15.16 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Nick Coghlan, Philip Jenvey, Ryan Lovett, R. David Murray, Hugh
Secker-Walker.


File: python.info,  Node: What’s New in Python 2 6,  Next: What’s New in Python 2 5,  Prev: What’s New in Python 2 7,  Up: What’s New in Python

1.16 What’s New in Python 2.6
=============================


Author: A.M. Kuchling (amk at amk.ca)

This article explains the new features in Python 2.6, released on
October 1, 2008.  The release schedule is described in PEP 361(1).

The major theme of Python 2.6 is preparing the migration path to Python
3.0, a major redesign of the language.  Whenever possible, Python 2.6
incorporates new features and syntax from 3.0 while remaining compatible
with existing code by not removing older features or syntax.  When it’s
not possible to do that, Python 2.6 tries to do what it can, adding
compatibility functions in a ‘future_builtins’ module and a ‘-3’ switch
to warn about usages that will become unsupported in 3.0.

Some significant new packages have been added to the standard library,
such as the *note multiprocessing: 94. and *note json: 82. modules, but
there aren’t many new features that aren’t related to Python 3.0 in some
way.

Python 2.6 also sees a number of improvements and bugfixes throughout
the source.  A search through the change logs finds there were 259
patches applied and 612 bugs fixed between Python 2.5 and 2.6.  Both
figures are likely to be underestimates.

This article doesn’t attempt to provide a complete specification of the
new features, but instead provides a convenient overview.  For full
details, you should refer to the documentation for Python 2.6.  If you
want to understand the rationale for the design and implementation,
refer to the PEP for a particular new feature.  Whenever possible,
“What’s New in Python” links to the bug/patch item for each change.

* Menu:

* Python 3.0: Python 3 0.
* Changes to the Development Process::
* PEP 343; The ‘with’ statement: PEP 343 The ‘with’ statement.
* PEP 366; Explicit Relative Imports From a Main Module: PEP 366 Explicit Relative Imports From a Main Module.
* PEP 370; Per-user site-packages Directory: PEP 370 Per-user site-packages Directory.
* PEP 371; The multiprocessing Package: PEP 371 The multiprocessing Package.
* PEP 3101; Advanced String Formatting: PEP 3101 Advanced String Formatting.
* PEP 3105; print As a Function: PEP 3105 print As a Function.
* PEP 3110; Exception-Handling Changes: PEP 3110 Exception-Handling Changes.
* PEP 3112; Byte Literals: PEP 3112 Byte Literals.
* PEP 3116; New I/O Library: PEP 3116 New I/O Library.
* PEP 3118; Revised Buffer Protocol: PEP 3118 Revised Buffer Protocol.
* PEP 3119; Abstract Base Classes: PEP 3119 Abstract Base Classes.
* PEP 3127; Integer Literal Support and Syntax: PEP 3127 Integer Literal Support and Syntax.
* PEP 3129; Class Decorators: PEP 3129 Class Decorators.
* PEP 3141; A Type Hierarchy for Numbers: PEP 3141 A Type Hierarchy for Numbers.
* Other Language Changes: Other Language Changes<15>.
* New and Improved Modules: New and Improved Modules<2>.
* Deprecations and Removals::
* Build and C API Changes: Build and C API Changes<9>.
* Porting to Python 2.6: Porting to Python 2 6.
* Acknowledgements: Acknowledgements<2>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0361/


File: python.info,  Node: Python 3 0,  Next: Changes to the Development Process,  Up: What’s New in Python 2 6

1.16.1 Python 3.0
-----------------

The development cycle for Python versions 2.6 and 3.0 was synchronized,
with the alpha and beta releases for both versions being made on the
same days.  The development of 3.0 has influenced many features in 2.6.

Python 3.0 is a far-ranging redesign of Python that breaks compatibility
with the 2.x series.  This means that existing Python code will need
some conversion in order to run on Python 3.0.  However, not all the
changes in 3.0 necessarily break compatibility.  In cases where new
features won’t cause existing code to break, they’ve been backported to
2.6 and are described in this document in the appropriate place.  Some
of the 3.0-derived features are:

   * A ‘__complex__()’ method for converting objects to a complex
     number.

   * Alternate syntax for catching exceptions: ‘except TypeError as
     exc’.

   * The addition of *note functools.reduce(): 1324. as a synonym for
     the built-in ‘reduce()’ function.

Python 3.0 adds several new built-in functions and changes the semantics
of some existing builtins.  Functions that are new in 3.0 such as *note
bin(): 12f0. have simply been added to Python 2.6, but existing builtins
haven’t been changed; instead, the ‘future_builtins’ module has versions
with the new 3.0 semantics.  Code written to be compatible with 3.0 can
do ‘from future_builtins import hex, map’ as necessary.

A new command-line switch, ‘-3’, enables warnings about features that
will be removed in Python 3.0.  You can run code with this switch to see
how much work will be necessary to port code to 3.0.  The value of this
switch is available to Python code as the boolean variable
‘sys.py3kwarning’, and to C extension code as ‘Py_Py3kWarningFlag’.

See also
........

The 3'xxx' series of PEPs, which contains proposals for Python 3.0.  PEP
3000(1) describes the development process for Python 3.0.  Start with
PEP 3100(2) that describes the general goals for Python 3.0, and then
explore the higher-numbered PEPs that propose specific features.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3000/

   (2) https://peps.python.org/pep-3100/


File: python.info,  Node: Changes to the Development Process,  Next: PEP 343 The ‘with’ statement,  Prev: Python 3 0,  Up: What’s New in Python 2 6

1.16.2 Changes to the Development Process
-----------------------------------------

While 2.6 was being developed, the Python development process underwent
two significant changes: we switched from SourceForge’s issue tracker to
a customized Roundup installation, and the documentation was converted
from LaTeX to reStructuredText.

* Menu:

* New Issue Tracker; Roundup: New Issue Tracker Roundup.
* New Documentation Format; reStructuredText Using Sphinx: New Documentation Format reStructuredText Using Sphinx.


File: python.info,  Node: New Issue Tracker Roundup,  Next: New Documentation Format reStructuredText Using Sphinx,  Up: Changes to the Development Process

1.16.2.1 New Issue Tracker: Roundup
...................................

For a long time, the Python developers had been growing increasingly
annoyed by SourceForge’s bug tracker.  SourceForge’s hosted solution
doesn’t permit much customization; for example, it wasn’t possible to
customize the life cycle of issues.

The infrastructure committee of the Python Software Foundation therefore
posted a call for issue trackers, asking volunteers to set up different
products and import some of the bugs and patches from SourceForge.  Four
different trackers were examined: Jira(1), Launchpad(2), Roundup(3), and
Trac(4).  The committee eventually settled on Jira and Roundup as the
two candidates.  Jira is a commercial product that offers no-cost hosted
instances to free-software projects; Roundup is an open-source project
that requires volunteers to administer it and a server to host it.

After posting a call for volunteers, a new Roundup installation was set
up at ‘https://bugs.python.org’.  One installation of Roundup can host
multiple trackers, and this server now also hosts issue trackers for
Jython and for the Python web site.  It will surely find other uses in
the future.  Where possible, this edition of “What’s New in Python”
links to the bug/patch item for each change.

Hosting of the Python bug tracker is kindly provided by Upfront
Systems(5) of Stellenbosch, South Africa.  Martin von Löwis put a lot of
effort into importing existing bugs and patches from SourceForge; his
scripts for this import operation are at
‘https://svn.python.org/view/tracker/importer/’ and may be useful to
other projects wishing to move from SourceForge to Roundup.

See also
........

‘https://bugs.python.org’

     The Python bug tracker.

‘https://bugs.jython.org’:

     The Jython bug tracker.

‘https://roundup.sourceforge.io/’

     Roundup downloads and documentation.

‘https://svn.python.org/view/tracker/importer/’

     Martin von Löwis’s conversion scripts.

   ---------- Footnotes ----------

   (1) https://www.atlassian.com/software/jira/

   (2) https://launchpad.net/

   (3) https://roundup.sourceforge.io/

   (4) https://trac.edgewall.org/

   (5) https://upfrontsoftware.co.za


File: python.info,  Node: New Documentation Format reStructuredText Using Sphinx,  Prev: New Issue Tracker Roundup,  Up: Changes to the Development Process

1.16.2.2 New Documentation Format: reStructuredText Using Sphinx
................................................................

The Python documentation was written using LaTeX since the project
started around 1989.  In the 1980s and early 1990s, most documentation
was printed out for later study, not viewed online.  LaTeX was widely
used because it provided attractive printed output while remaining
straightforward to write once the basic rules of the markup were
learned.

Today LaTeX is still used for writing publications destined for
printing, but the landscape for programming tools has shifted.  We no
longer print out reams of documentation; instead, we browse through it
online and HTML has become the most important format to support.
Unfortunately, converting LaTeX to HTML is fairly complicated and Fred
L.  Drake Jr., the long-time Python documentation editor, spent a lot of
time maintaining the conversion process.  Occasionally people would
suggest converting the documentation into SGML and later XML, but
performing a good conversion is a major task and no one ever committed
the time required to finish the job.

During the 2.6 development cycle, Georg Brandl put a lot of effort into
building a new toolchain for processing the documentation.  The
resulting package is called Sphinx, and is available from
‘https://www.sphinx-doc.org/’.

Sphinx concentrates on HTML output, producing attractively styled and
modern HTML; printed output is still supported through conversion to
LaTeX. The input format is reStructuredText, a markup syntax supporting
custom extensions and directives that is commonly used in the Python
community.

Sphinx is a standalone package that can be used for writing, and almost
two dozen other projects (listed on the Sphinx web site(1)) have adopted
Sphinx as their documentation tool.

See also
........

Documenting Python(2)

     Describes how to write for Python’s documentation.

Sphinx(3)

     Documentation and code for the Sphinx toolchain.

Docutils(4)

     The underlying reStructuredText parser and toolset.

   ---------- Footnotes ----------

   (1) https://www.sphinx-doc.org/en/master/examples.html

   (2) https://devguide.python.org/documenting/

   (3) https://www.sphinx-doc.org/

   (4) https://docutils.sourceforge.io


File: python.info,  Node: PEP 343 The ‘with’ statement,  Next: PEP 366 Explicit Relative Imports From a Main Module,  Prev: Changes to the Development Process,  Up: What’s New in Python 2 6

1.16.3 PEP 343: The ‘with’ statement
------------------------------------

The previous version, Python 2.5, added the ‘*note with: 5d5.’ statement
as an optional feature, to be enabled by a ‘from __future__ import
with_statement’ directive.  In 2.6 the statement no longer needs to be
specially enabled; this means that ‘with’ is now always a keyword.  The
rest of this section is a copy of the corresponding section from the
“What’s New in Python 2.5” document; if you’re familiar with the
‘‘with’’ statement from Python 2.5, you can skip this section.

The ‘*note with: 5d5.’ statement clarifies code that previously would
use ‘try...finally’ blocks to ensure that clean-up code is executed.  In
this section, I’ll discuss the statement as it will commonly be used.
In the next section, I’ll examine the implementation details and show
how to write objects for use with this statement.

The ‘*note with: 5d5.’ statement is a control-flow structure whose basic
structure is:

     with expression [as variable]:
         with-block

The expression is evaluated, and it should result in an object that
supports the context management protocol (that is, has *note
__enter__(): 5cb. and *note __exit__(): 1349. methods).

The object’s *note __enter__(): 5cb. is called before 'with-block' is
executed and therefore can run set-up code.  It also may return a value
that is bound to the name 'variable', if given.  (Note carefully that
'variable' is 'not' assigned the result of 'expression'.)

After execution of the 'with-block' is finished, the object’s *note
__exit__(): 1349. method is called, even if the block raised an
exception, and can therefore run clean-up code.

Some standard Python objects now support the context management protocol
and can be used with the ‘*note with: 5d5.’ statement.  File objects are
one example:

     with open('/etc/passwd', 'r') as f:
         for line in f:
             print line
             ... more processing code ...

After this statement has executed, the file object in 'f' will have been
automatically closed, even if the *note for: 2f2. loop raised an
exception part-way through the block.

     Note: In this case, 'f' is the same object created by *note open():
     51f, because *note __enter__(): 5cb. returns 'self'.

The *note threading: ed. module’s locks and condition variables also
support the ‘*note with: 5d5.’ statement:

     lock = threading.Lock()
     with lock:
         # Critical section of code
         ...

The lock is acquired before the block is executed and always released
once the block is complete.

The *note localcontext(): 13d3. function in the *note decimal: 36.
module makes it easy to save and restore the current decimal context,
which encapsulates the desired precision and rounding characteristics
for computations:

     from decimal import Decimal, Context, localcontext

     # Displays with default precision of 28 digits
     v = Decimal('578')
     print v.sqrt()

     with localcontext(Context(prec=16)):
         # All code in this block uses a precision of 16 digits.
         # The original context is restored on exiting the block.
         print v.sqrt()

* Menu:

* Writing Context Managers::
* The contextlib module::


File: python.info,  Node: Writing Context Managers,  Next: The contextlib module,  Up: PEP 343 The ‘with’ statement

1.16.3.1 Writing Context Managers
.................................

Under the hood, the ‘*note with: 5d5.’ statement is fairly complicated.
Most people will only use ‘‘with’’ in company with existing objects and
don’t need to know these details, so you can skip the rest of this
section if you like.  Authors of new objects will need to understand the
details of the underlying implementation and should keep reading.

A high-level explanation of the context management protocol is:

   * The expression is evaluated and should result in an object called a
     “context manager”.  The context manager must have *note
     __enter__(): 5cb. and *note __exit__(): 1349. methods.

   * The context manager’s *note __enter__(): 5cb. method is called.
     The value returned is assigned to 'VAR'. If no ‘as VAR’ clause is
     present, the value is simply discarded.

   * The code in 'BLOCK' is executed.

   * If 'BLOCK' raises an exception, the context manager’s *note
     __exit__(): 1349. method is called with three arguments, the
     exception details (‘type, value, traceback’, the same values
     returned by *note sys.exc_info(): 68d, which can also be ‘None’ if
     no exception occurred).  The method’s return value controls whether
     an exception is re-raised: any false value re-raises the exception,
     and ‘True’ will result in suppressing it.  You’ll only rarely want
     to suppress the exception, because if you do the author of the code
     containing the ‘*note with: 5d5.’ statement will never realize
     anything went wrong.

   * If 'BLOCK' didn’t raise an exception, the *note __exit__(): 1349.
     method is still called, but 'type', 'value', and 'traceback' are
     all ‘None’.

Let’s think through an example.  I won’t present detailed code but will
only sketch the methods necessary for a database that supports
transactions.

(For people unfamiliar with database terminology: a set of changes to
the database are grouped into a transaction.  Transactions can be either
committed, meaning that all the changes are written into the database,
or rolled back, meaning that the changes are all discarded and the
database is unchanged.  See any database textbook for more information.)

Let’s assume there’s an object representing a database connection.  Our
goal will be to let the user write code like this:

     db_connection = DatabaseConnection()
     with db_connection as cursor:
         cursor.execute('insert into ...')
         cursor.execute('delete from ...')
         # ... more operations ...

The transaction should be committed if the code in the block runs
flawlessly or rolled back if there’s an exception.  Here’s the basic
interface for ‘DatabaseConnection’ that I’ll assume:

     class DatabaseConnection:
         # Database interface
         def cursor(self):
             "Returns a cursor object and starts a new transaction"
         def commit(self):
             "Commits current transaction"
         def rollback(self):
             "Rolls back current transaction"

The *note __enter__(): 5cb. method is pretty easy, having only to start
a new transaction.  For this application the resulting cursor object
would be a useful result, so the method will return it.  The user can
then add ‘as cursor’ to their ‘*note with: 5d5.’ statement to bind the
cursor to a variable name.

     class DatabaseConnection:
         ...
         def __enter__(self):
             # Code to start a new transaction
             cursor = self.cursor()
             return cursor

The *note __exit__(): 1349. method is the most complicated because it’s
where most of the work has to be done.  The method has to check if an
exception occurred.  If there was no exception, the transaction is
committed.  The transaction is rolled back if there was an exception.

In the code below, execution will just fall off the end of the function,
returning the default value of ‘None’.  ‘None’ is false, so the
exception will be re-raised automatically.  If you wished, you could be
more explicit and add a *note return: 9d9. statement at the marked
location.

     class DatabaseConnection:
         ...
         def __exit__(self, type, value, tb):
             if tb is None:
                 # No exception, so commit
                 self.commit()
             else:
                 # Exception occurred, so rollback.
                 self.rollback()
                 # return False


File: python.info,  Node: The contextlib module,  Prev: Writing Context Managers,  Up: PEP 343 The ‘with’ statement

1.16.3.2 The contextlib module
..............................

The *note contextlib: 23. module provides some functions and a decorator
that are useful when writing objects for use with the ‘*note with: 5d5.’
statement.

The decorator is called *note contextmanager(): 1247, and lets you write
a single generator function instead of defining a new class.  The
generator should yield exactly one value.  The code up to the *note
yield: 9d8. will be executed as the *note __enter__(): 5cb. method, and
the value yielded will be the method’s return value that will get bound
to the variable in the ‘*note with: 5d5.’ statement’s ‘as’ clause, if
any.  The code after the ‘yield’ will be executed in the *note
__exit__(): 1349. method.  Any exception raised in the block will be
raised by the ‘yield’ statement.

Using this decorator, our database example from the previous section
could be written as:

     from contextlib import contextmanager

     @contextmanager
     def db_transaction(connection):
         cursor = connection.cursor()
         try:
             yield cursor
         except:
             connection.rollback()
             raise
         else:
             connection.commit()

     db = DatabaseConnection()
     with db_transaction(db) as cursor:
         ...

The *note contextlib: 23. module also has a ‘nested(mgr1, mgr2, ...)’
function that combines a number of context managers so you don’t need to
write nested ‘*note with: 5d5.’ statements.  In this example, the single
‘‘with’’ statement both starts a database transaction and acquires a
thread lock:

     lock = threading.Lock()
     with nested (db_transaction(db), lock) as (cursor, locked):
         ...

Finally, the *note closing(): 13d6. function returns its argument so
that it can be bound to a variable, and calls the argument’s ‘.close()’
method at the end of the block.

     import urllib, sys
     from contextlib import closing

     with closing(urllib.urlopen('http://www.yahoo.com')) as f:
         for line in f:
             sys.stdout.write(line)

See also
........

PEP 343(1) - The “with” statement

     PEP written by Guido van Rossum and Nick Coghlan; implemented by
     Mike Bland, Guido van Rossum, and Neal Norwitz.  The PEP shows the
     code generated for a ‘*note with: 5d5.’ statement, which can be
     helpful in learning how the statement works.

The documentation for the *note contextlib: 23. module.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0343/


File: python.info,  Node: PEP 366 Explicit Relative Imports From a Main Module,  Next: PEP 370 Per-user site-packages Directory,  Prev: PEP 343 The ‘with’ statement,  Up: What’s New in Python 2 6

1.16.4 PEP 366: Explicit Relative Imports From a Main Module
------------------------------------------------------------

Python’s *note -m: 5e4. switch allows running a module as a script.
When you ran a module that was located inside a package, relative
imports didn’t work correctly.

The fix for Python 2.6 adds a *note module.__package__: 2d7. attribute.
When this attribute is present, relative imports will be relative to the
value of this attribute instead of the *note __name__: 13d8. attribute.

PEP 302-style importers can then set *note __package__: 2d7. as
necessary.  The *note runpy: be. module that implements the *note -m:
5e4. switch now does this, so relative imports will now work correctly
in scripts running from inside a package.


File: python.info,  Node: PEP 370 Per-user site-packages Directory,  Next: PEP 371 The multiprocessing Package,  Prev: PEP 366 Explicit Relative Imports From a Main Module,  Up: What’s New in Python 2 6

1.16.5 PEP 370: Per-user ‘site-packages’ Directory
--------------------------------------------------

When you run Python, the module search path ‘sys.path’ usually includes
a directory whose path ends in ‘"site-packages"’.  This directory is
intended to hold locally installed packages available to all users using
a machine or a particular site installation.

Python 2.6 introduces a convention for user-specific site directories.
The directory varies depending on the platform:

   * Unix and Mac OS X: ‘~/.local/’

   * Windows: ‘%APPDATA%/Python’

Within this directory, there will be version-specific subdirectories,
such as ‘lib/python2.6/site-packages’ on Unix/Mac OS and
‘Python26/site-packages’ on Windows.

If you don’t like the default directory, it can be overridden by an
environment variable.  *note PYTHONUSERBASE: 13da. sets the root
directory used for all Python versions supporting this feature.  On
Windows, the directory for application-specific data can be changed by
setting the ‘APPDATA’ environment variable.  You can also modify the
‘site.py’ file for your Python installation.

The feature can be disabled entirely by running Python with the *note
-s: 13db. option or setting the *note PYTHONNOUSERSITE: 13dc.
environment variable.

See also
........

PEP 370(1) - Per-user ‘site-packages’ Directory

     PEP written and implemented by Christian Heimes.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0370/


File: python.info,  Node: PEP 371 The multiprocessing Package,  Next: PEP 3101 Advanced String Formatting,  Prev: PEP 370 Per-user site-packages Directory,  Up: What’s New in Python 2 6

1.16.6 PEP 371: The ‘multiprocessing’ Package
---------------------------------------------

The new *note multiprocessing: 94. package lets Python programs create
new processes that will perform a computation and return a result to the
parent.  The parent and child processes can communicate using queues and
pipes, synchronize their operations using locks and semaphores, and can
share simple arrays of data.

The *note multiprocessing: 94. module started out as an exact emulation
of the *note threading: ed. module using processes instead of threads.
That goal was discarded along the path to Python 2.6, but the general
approach of the module is still similar.  The fundamental class is the
*note Process: b75, which is passed a callable object and a collection
of arguments.  The *note start(): 13de. method sets the callable running
in a subprocess, after which you can call the *note is_alive(): 13df.
method to check whether the subprocess is still running and the *note
join(): 13e0. method to wait for the process to exit.

Here’s a simple example where the subprocess will calculate a factorial.
The function doing the calculation is written strangely so that it takes
significantly longer when the input argument is a multiple of 4.

     import time
     from multiprocessing import Process, Queue


     def factorial(queue, N):
         "Compute a factorial."
         # If N is a multiple of 4, this function will take much longer.
         if (N % 4) == 0:
             time.sleep(.05 * N/4)

         # Calculate the result
         fact = 1L
         for i in range(1, N+1):
             fact = fact * i

         # Put the result on the queue
         queue.put(fact)

     if __name__ == '__main__':
         queue = Queue()

         N = 5

         p = Process(target=factorial, args=(queue, N))
         p.start()
         p.join()

         result = queue.get()
         print 'Factorial', N, '=', result

A *note Queue: 13e1. is used to communicate the result of the factorial.
The ‘Queue’ object is stored in a global variable.  The child process
will use the value of the variable when the child was created; because
it’s a ‘Queue’, parent and child can use the object to communicate.  (If
the parent were to change the value of the global variable, the child’s
value would be unaffected, and vice versa.)

Two other classes, *note Pool: fa4. and *note Manager: ce0, provide
higher-level interfaces.  ‘Pool’ will create a fixed number of worker
processes, and requests can then be distributed to the workers by
calling *note apply(): 13e2. or *note apply_async(): 13e3. to add a
single request, and *note map(): 1129. or *note map_async(): 112a. to
add a number of requests.  The following code uses a ‘Pool’ to spread
requests across 5 worker processes and retrieve a list of results:

     from multiprocessing import Pool

     def factorial(N, dictionary):
         "Compute a factorial."
         ...
     p = Pool(5)
     result = p.map(factorial, range(1, 1000, 10))
     for v in result:
         print v

This produces the following output:

     1
     39916800
     51090942171709440000
     8222838654177922817725562880000000
     33452526613163807108170062053440751665152000000000
     ...

The other high-level interface, the *note Manager: ce0. class, creates a
separate server process that can hold master copies of Python data
structures.  Other processes can then access and modify these data
structures using proxy objects.  The following example creates a shared
dictionary by calling the *note dict(): 256. method; the worker
processes then insert values into the dictionary.  (Locking is not done
for you automatically, which doesn’t matter in this example.
‘Manager’’s methods also include *note Lock(): 13e4, *note RLock():
13e5, and *note Semaphore(): 13e6. to create shared locks.)

     import time
     from multiprocessing import Pool, Manager

     def factorial(N, dictionary):
         "Compute a factorial."
         # Calculate the result
         fact = 1L
         for i in range(1, N+1):
             fact = fact * i

         # Store result in dictionary
         dictionary[N] = fact

     if __name__ == '__main__':
         p = Pool(5)
         mgr = Manager()
         d = mgr.dict()         # Create shared dictionary

         # Run tasks using the pool
         for N in range(1, 1000, 10):
             p.apply_async(factorial, (N, d))

         # Mark pool as closed -- no more tasks can be added.
         p.close()

         # Wait for tasks to exit
         p.join()

         # Output results
         for k, v in sorted(d.items()):
             print k, v

This will produce the output:

     1 1
     11 39916800
     21 51090942171709440000
     31 8222838654177922817725562880000000
     41 33452526613163807108170062053440751665152000000000
     51 15511187532873822802242430164693032110632597200169861120000...

See also
........

The documentation for the *note multiprocessing: 94. module.

PEP 371(1) - Addition of the multiprocessing package

     PEP written by Jesse Noller and Richard Oudkerk; implemented by
     Richard Oudkerk and Jesse Noller.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0371/


File: python.info,  Node: PEP 3101 Advanced String Formatting,  Next: PEP 3105 print As a Function,  Prev: PEP 371 The multiprocessing Package,  Up: What’s New in Python 2 6

1.16.7 PEP 3101: Advanced String Formatting
-------------------------------------------

In Python 3.0, the ‘%’ operator is supplemented by a more powerful
string formatting method, *note format(): 622.  Support for the *note
str.format(): 624. method has been backported to Python 2.6.

In 2.6, both 8-bit and Unicode strings have a ‘.format()’ method that
treats the string as a template and takes the arguments to be formatted.
The formatting template uses curly brackets (‘{’, ‘}’) as special
characters:

     >>> # Substitute positional argument 0 into the string.
     >>> "User ID: {0}".format("root")
     'User ID: root'
     >>> # Use the named keyword arguments
     >>> "User ID: {uid}   Last seen: {last_login}".format(
     ...    uid="root",
     ...    last_login = "5 Mar 2008 07:20")
     'User ID: root   Last seen: 5 Mar 2008 07:20'

Curly brackets can be escaped by doubling them:

     >>> "Empty dict: {{}}".format()
     "Empty dict: {}"

Field names can be integers indicating positional arguments, such as
‘{0}’, ‘{1}’, etc.  or names of keyword arguments.  You can also supply
compound field names that read attributes or access dictionary keys:

     >>> import sys
     >>> print 'Platform: {0.platform}\nPython version: {0.version}'.format(sys)
     Platform: darwin
     Python version: 2.6a1+ (trunk:61261M, Mar  5 2008, 20:29:41)
     [GCC 4.0.1 (Apple Computer, Inc. build 5367)]'

     >>> import mimetypes
     >>> 'Content-type: {0[.mp4]}'.format(mimetypes.types_map)
     'Content-type: video/mp4'

Note that when using dictionary-style notation such as ‘[.mp4]’, you
don’t need to put any quotation marks around the string; it will look up
the value using ‘.mp4’ as the key.  Strings beginning with a number will
be converted to an integer.  You can’t write more complicated
expressions inside a format string.

So far we’ve shown how to specify which field to substitute into the
resulting string.  The precise formatting used is also controllable by
adding a colon followed by a format specifier.  For example:

     >>> # Field 0: left justify, pad to 15 characters
     >>> # Field 1: right justify, pad to 6 characters
     >>> fmt = '{0:15} ${1:>6}'
     >>> fmt.format('Registration', 35)
     'Registration    $    35'
     >>> fmt.format('Tutorial', 50)
     'Tutorial        $    50'
     >>> fmt.format('Banquet', 125)
     'Banquet         $   125'

Format specifiers can reference other fields through nesting:

     >>> fmt = '{0:{1}}'
     >>> width = 15
     >>> fmt.format('Invoice #1234', width)
     'Invoice #1234  '
     >>> width = 35
     >>> fmt.format('Invoice #1234', width)
     'Invoice #1234                      '

The alignment of a field within the desired width can be specified:

Character            Effect
                     
----------------------------------------------------------------------
                     
< (default)          Left-align
                     
                     
>                    Right-align
                     
                     
^                    Center
                     
                     
=                    (For numeric types only) Pad after the sign.
                     

Format specifiers can also include a presentation type, which controls
how the value is formatted.  For example, floating-point numbers can be
formatted as a general number or in exponential notation:

     >>> '{0:g}'.format(3.75)
     '3.75'
     >>> '{0:e}'.format(3.75)
     '3.750000e+00'

A variety of presentation types are available.  Consult the 2.6
documentation for a *note complete list: 13e8.; here’s a sample:

‘b’       Binary.  Outputs the number in base 2.
          
          
‘c’       Character.  Converts the integer to the corresponding Unicode character
          before printing.
          
          
‘d’       Decimal Integer.  Outputs the number in base 10.
          
          
‘o’       Octal format.  Outputs the number in base 8.
          
          
‘x’       Hex format.  Outputs the number in base 16, using lower-case letters for
          the digits above 9.
          
          
‘e’       Exponent notation.  Prints the number in scientific notation using the
          letter ‘e’ to indicate the exponent.
          
          
‘g’       General format.  This prints the number as a fixed-point number, unless
          the number is too large, in which case it switches to ‘e’ exponent
          notation.
          
          
‘n’       Number.  This is the same as ‘g’ (for floats) or ‘d’ (for integers),
          except that it uses the current locale setting to insert the appropriate
          number separator characters.
          
          
‘%’       Percentage.  Multiplies the number by 100 and displays in fixed (‘f’)
          format, followed by a percent sign.
          

Classes and types can define a *note __format__(): 621. method to
control how they’re formatted.  It receives a single argument, the
format specifier:

     def __format__(self, format_spec):
         if isinstance(format_spec, unicode):
             return unicode(str(self))
         else:
             return str(self)

There’s also a *note format(): 622. builtin that will format a single
value.  It calls the type’s *note __format__(): 621. method with the
provided specifier:

     >>> format(75.6564, '.2f')
     '75.66'

See also
........

*note Format string syntax: 13e8.

     The reference documentation for format fields.

PEP 3101(1) - Advanced String Formatting

     PEP written by Talin.  Implemented by Eric Smith.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3101/


File: python.info,  Node: PEP 3105 print As a Function,  Next: PEP 3110 Exception-Handling Changes,  Prev: PEP 3101 Advanced String Formatting,  Up: What’s New in Python 2 6

1.16.8 PEP 3105: ‘print’ As a Function
--------------------------------------

The ‘print’ statement becomes the *note print(): fae. function in Python
3.0.  Making ‘print()’ a function makes it possible to replace the
function by doing ‘def print(...)’ or importing a new function from
somewhere else.

Python 2.6 has a ‘__future__’ import that removes ‘print’ as language
syntax, letting you use the functional form instead.  For example:

     >>> from __future__ import print_function
     >>> print('# of entries', len(dictionary), file=sys.stderr)

The signature of the new function is:

     def print(*args, sep=' ', end='\n', file=None)

The parameters are:

   * 'args': positional arguments whose values will be printed out.

   * 'sep': the separator, which will be printed between arguments.

   * 'end': the ending text, which will be printed after all of the
     arguments have been output.

   * 'file': the file object to which the output will be sent.

See also
........

PEP 3105(1) - Make print a function

     PEP written by Georg Brandl.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3105/


File: python.info,  Node: PEP 3110 Exception-Handling Changes,  Next: PEP 3112 Byte Literals,  Prev: PEP 3105 print As a Function,  Up: What’s New in Python 2 6

1.16.9 PEP 3110: Exception-Handling Changes
-------------------------------------------

One error that Python programmers occasionally make is writing the
following code:

     try:
         ...
     except TypeError, ValueError:  # Wrong!
         ...

The author is probably trying to catch both *note TypeError: 2c3. and
*note ValueError: 202. exceptions, but this code actually does something
different: it will catch ‘TypeError’ and bind the resulting exception
object to the local name ‘"ValueError"’.  The ‘ValueError’ exception
will not be caught at all.  The correct code specifies a tuple of
exceptions:

     try:
         ...
     except (TypeError, ValueError):
         ...

This error happens because the use of the comma here is ambiguous: does
it indicate two different nodes in the parse tree, or a single node
that’s a tuple?

Python 3.0 makes this unambiguous by replacing the comma with the word
“as”.  To catch an exception and store the exception object in the
variable ‘exc’, you must write:

     try:
         ...
     except TypeError as exc:
         ...

Python 3.0 will only support the use of “as”, and therefore interprets
the first example as catching two different exceptions.  Python 2.6
supports both the comma and “as”, so existing code will continue to
work.  We therefore suggest using “as” when writing new Python code that
will only be executed with 2.6.

See also
........

PEP 3110(1) - Catching Exceptions in Python 3000

     PEP written and implemented by Collin Winter.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3110/


File: python.info,  Node: PEP 3112 Byte Literals,  Next: PEP 3116 New I/O Library,  Prev: PEP 3110 Exception-Handling Changes,  Up: What’s New in Python 2 6

1.16.10 PEP 3112: Byte Literals
-------------------------------

Python 3.0 adopts Unicode as the language’s fundamental string type and
denotes 8-bit literals differently, either as ‘b'string'’ or using a
*note bytes: 1c2. constructor.  For future compatibility, Python 2.6
adds ‘bytes’ as a synonym for the *note str: 44f. type, and it also
supports the ‘b''’ notation.

The 2.6 *note str: 44f. differs from 3.0’s *note bytes: 1c2. type in
various ways; most notably, the constructor is completely different.  In
3.0, ‘bytes([65, 66, 67])’ is 3 elements long, containing the bytes
representing ‘ABC’; in 2.6, ‘bytes([65, 66, 67])’ returns the 12-byte
string representing the *note str(): 44f. of the list.

The primary use of *note bytes: 1c2. in 2.6 will be to write tests of
object type such as ‘isinstance(x, bytes)’.  This will help the 2to3
converter, which can’t tell whether 2.x code intends strings to contain
either characters or 8-bit bytes; you can now use either ‘bytes’ or
*note str: 44f. to represent your intention exactly, and the resulting
code will also be correct in Python 3.0.

There’s also a ‘__future__’ import that causes all string literals to
become Unicode strings.  This means that ‘\u’ escape sequences can be
used to include Unicode characters:

     from __future__ import unicode_literals

     s = ('\u751f\u3080\u304e\u3000\u751f\u3054'
          '\u3081\u3000\u751f\u305f\u307e\u3054')

     print len(s)               # 12 Unicode characters

At the C level, Python 3.0 will rename the existing 8-bit string type,
called ‘PyStringObject’ in Python 2.x, to *note PyBytesObject: 795.
Python 2.6 uses ‘#define’ to support using the names *note
PyBytesObject(): 795, *note PyBytes_Check(): 13ec, *note
PyBytes_FromStringAndSize(): 13ed, and all the other functions and
macros used with strings.

Instances of the *note bytes: 1c2. type are immutable just as strings
are.  A new *note bytearray: 2ea. type stores a mutable sequence of
bytes:

     >>> bytearray([65, 66, 67])
     bytearray(b'ABC')
     >>> b = bytearray(u'\u21ef\u3244', 'utf-8')
     >>> b
     bytearray(b'\xe2\x87\xaf\xe3\x89\x84')
     >>> b[0] = '\xe3'
     >>> b
     bytearray(b'\xe3\x87\xaf\xe3\x89\x84')
     >>> unicode(str(b), 'utf-8')
     u'\u31ef \u3244'

Byte arrays support most of the methods of string types, such as *note
startswith(): 13ee./*note endswith(): 13ef, *note find(): 13f0./*note
rfind(): 13f1, and some of the methods of lists, such as *note append():
13f2, *note pop(): 13f3, and *note reverse(): 13f4.

     >>> b = bytearray('ABC')
     >>> b.append('d')
     >>> b.append(ord('e'))
     >>> b
     bytearray(b'ABCde')

There’s also a corresponding C API, with *note PyByteArray_FromObject():
13f5, *note PyByteArray_FromStringAndSize(): 13f6, and various other
functions.

See also
........

PEP 3112(1) - Bytes literals in Python 3000

     PEP written by Jason Orendorff; backported to 2.6 by Christian
     Heimes.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3112/


File: python.info,  Node: PEP 3116 New I/O Library,  Next: PEP 3118 Revised Buffer Protocol,  Prev: PEP 3112 Byte Literals,  Up: What’s New in Python 2 6

1.16.11 PEP 3116: New I/O Library
---------------------------------

Python’s built-in file objects support a number of methods, but
file-like objects don’t necessarily support all of them.  Objects that
imitate files usually support ‘read()’ and ‘write()’, but they may not
support ‘readline()’, for example.  Python 3.0 introduces a layered I/O
library in the *note io: 7f. module that separates buffering and
text-handling features from the fundamental read and write operations.

There are three levels of abstract base classes provided by the *note
io: 7f. module:

   * *note RawIOBase: 1114. defines raw I/O operations: *note read():
     e4e, *note readinto(): e4f, *note write(): 13f8, *note seek():
     12d3, *note tell(): 13f9, *note truncate(): 135a, and *note
     close(): 1f6.  Most of the methods of this class will often map to
     a single system call.  There are also *note readable(): 13fa, *note
     writable(): 13fb, and *note seekable(): 13fc. methods for
     determining what operations a given object will allow.

     Python 3.0 has concrete implementations of this class for files and
     sockets, but Python 2.6 hasn’t restructured its file and socket
     objects in this way.

   * *note BufferedIOBase: 697. is an abstract base class that buffers
     data in memory to reduce the number of system calls used, making
     I/O processing more efficient.  It supports all of the methods of
     *note RawIOBase: 1114, and adds a *note raw: 13fd. attribute
     holding the underlying raw object.

     There are five concrete classes implementing this ABC. *note
     BufferedWriter: 13fe. and *note BufferedReader: 1253. are for
     objects that support write-only or read-only usage that have a
     *note seek(): 12d3. method for random access.  *note
     BufferedRandom: 13ff. objects support read and write access upon
     the same underlying stream, and *note BufferedRWPair: 1400. is for
     objects such as TTYs that have both read and write operations
     acting upon unconnected streams of data.  The *note BytesIO: ed8.
     class supports reading, writing, and seeking over an in-memory
     buffer.

   * *note TextIOBase: 698.: Provides functions for reading and writing
     strings (remember, strings will be Unicode in Python 3.0), and
     supporting *note universal newlines: d62.  ‘TextIOBase’ defines the
     *note readline(): ba. method and supports iteration upon objects.

     There are two concrete implementations.  *note TextIOWrapper: 7bf.
     wraps a buffered I/O object, supporting all of the methods for text
     I/O and adding a *note buffer: 12ea. attribute for access to the
     underlying object.  *note StringIO: f5e. simply buffers everything
     in memory without ever writing anything to disk.

     (In Python 2.6, *note io.StringIO: f5e. is implemented in pure
     Python, so it’s pretty slow.  You should therefore stick with the
     existing ‘StringIO’ module or ‘cStringIO’ for now.  At some point
     Python 3.0’s *note io: 7f. module will be rewritten into C for
     speed, and perhaps the C implementation will be backported to the
     2.x releases.)

In Python 2.6, the underlying implementations haven’t been restructured
to build on top of the *note io: 7f. module’s classes.  The module is
being provided to make it easier to write code that’s forward-compatible
with 3.0, and to save developers the effort of writing their own
implementations of buffering and text I/O.

See also
........

PEP 3116(1) - New I/O

     PEP written by Daniel Stutzbach, Mike Verdone, and Guido van
     Rossum.  Code by Guido van Rossum, Georg Brandl, Walter Doerwald,
     Jeremy Hylton, Martin von Löwis, Tony Lownds, and others.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3116/


File: python.info,  Node: PEP 3118 Revised Buffer Protocol,  Next: PEP 3119 Abstract Base Classes,  Prev: PEP 3116 New I/O Library,  Up: What’s New in Python 2 6

1.16.12 PEP 3118: Revised Buffer Protocol
-----------------------------------------

The buffer protocol is a C-level API that lets Python types exchange
pointers into their internal representations.  A memory-mapped file can
be viewed as a buffer of characters, for example, and this lets another
module such as *note re: b9. treat memory-mapped files as a string of
characters to be searched.

The primary users of the buffer protocol are numeric-processing packages
such as NumPy, which expose the internal representation of arrays so
that callers can write data directly into an array instead of going
through a slower API. This PEP updates the buffer protocol in light of
experience from NumPy development, adding a number of new features such
as indicating the shape of an array or locking a memory region.

The most important new C API function is ‘PyObject_GetBuffer(PyObject
*obj, Py_buffer *view, int flags)’, which takes an object and a set of
flags, and fills in the ‘Py_buffer’ structure with information about the
object’s memory representation.  Objects can use this operation to lock
memory in place while an external caller could be modifying the
contents, so there’s a corresponding ‘PyBuffer_Release(Py_buffer *view)’
to indicate that the external caller is done.

The 'flags' argument to *note PyObject_GetBuffer(): 39c. specifies
constraints upon the memory returned.  Some examples are:

   * *note PyBUF_WRITABLE: 1402. indicates that the memory must be
     writable.

   * ‘PyBUF_LOCK’ requests a read-only or exclusive lock on the memory.

   * *note PyBUF_C_CONTIGUOUS: 1403. and *note PyBUF_F_CONTIGUOUS: 1404.
     requests a C-contiguous (last dimension varies the fastest) or
     Fortran-contiguous (first dimension varies the fastest) array
     layout.

Two new argument codes for *note PyArg_ParseTuple(): 574, ‘s*’ and ‘z*’,
return locked buffer objects for a parameter.

See also
........

PEP 3118(1) - Revising the buffer protocol

     PEP written by Travis Oliphant and Carl Banks; implemented by
     Travis Oliphant.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/


File: python.info,  Node: PEP 3119 Abstract Base Classes,  Next: PEP 3127 Integer Literal Support and Syntax,  Prev: PEP 3118 Revised Buffer Protocol,  Up: What’s New in Python 2 6

1.16.13 PEP 3119: Abstract Base Classes
---------------------------------------

Some object-oriented languages such as Java support interfaces,
declaring that a class has a given set of methods or supports a given
access protocol.  Abstract Base Classes (or ABCs) are an equivalent
feature for Python.  The ABC support consists of an *note abc: 4. module
containing a metaclass called *note ABCMeta: f4f, special handling of
this metaclass by the *note isinstance(): 445. and *note issubclass():
7c5. builtins, and a collection of basic ABCs that the Python developers
think will be widely useful.  Future versions of Python will probably
add more ABCs.

Let’s say you have a particular class and wish to know whether it
supports dictionary-style access.  The phrase “dictionary-style” is
vague, however.  It probably means that accessing items with ‘obj[1]’
works.  Does it imply that setting items with ‘obj[2] = value’ works?
Or that the object will have ‘keys()’, ‘values()’, and ‘items()’
methods?  What about the iterative variants such as ‘iterkeys()’?
‘copy`and :meth:()’!update'?  Iterating over the object with ‘iter()’?

The Python 2.6 *note collections: 1d. module includes a number of
different ABCs that represent these distinctions.  ‘Iterable’ indicates
that a class defines *note __iter__(): c90, and ‘Container’ means the
class defines a *note __contains__(): 1406. method and therefore
supports ‘x in y’ expressions.  The basic dictionary interface of
getting items, setting items, and ‘keys()’, ‘values()’, and ‘items()’,
is defined by the ‘MutableMapping’ ABC.

You can derive your own classes from a particular ABC to indicate they
support that ABC’s interface:

     import collections

     class Storage(collections.MutableMapping):
         ...

Alternatively, you could write the class without deriving from the
desired ABC and instead register the class by calling the ABC’s *note
register(): 10cc. method:

     import collections

     class Storage:
         ...

     collections.MutableMapping.register(Storage)

For classes that you write, deriving from the ABC is probably clearer.
The *note register(): 10cc. method is useful when you’ve written a new
ABC that can describe an existing type or class, or if you want to
declare that some third-party class implements an ABC. For example, if
you defined a ‘PrintableType’ ABC, it’s legal to do:

     # Register Python's types
     PrintableType.register(int)
     PrintableType.register(float)
     PrintableType.register(str)

Classes should obey the semantics specified by an ABC, but Python can’t
check this; it’s up to the class author to understand the ABC’s
requirements and to implement the code accordingly.

To check whether an object supports a particular interface, you can now
write:

     def func(d):
         if not isinstance(d, collections.MutableMapping):
             raise ValueError("Mapping object expected, not %r" % d)

Don’t feel that you must now begin writing lots of checks as in the
above example.  Python has a strong tradition of duck-typing, where
explicit type-checking is never done and code simply calls methods on an
object, trusting that those methods will be there and raising an
exception if they aren’t.  Be judicious in checking for ABCs and only do
it where it’s absolutely necessary.

You can write your own ABCs by using ‘abc.ABCMeta’ as the metaclass in a
class definition:

     from abc import ABCMeta, abstractmethod

     class Drawable():
         __metaclass__ = ABCMeta

         @abstractmethod
         def draw(self, x, y, scale=1.0):
             pass

         def draw_doubled(self, x, y):
             self.draw(x, y, scale=2.0)


     class Square(Drawable):
         def draw(self, x, y, scale):
             ...

In the ‘Drawable’ ABC above, the ‘draw_doubled()’ method renders the
object at twice its size and can be implemented in terms of other
methods described in ‘Drawable’.  Classes implementing this ABC
therefore don’t need to provide their own implementation of
‘draw_doubled()’, though they can do so.  An implementation of ‘draw()’
is necessary, though; the ABC can’t provide a useful generic
implementation.

You can apply the *note @~abc.abstractmethod: 10c9. decorator to methods
such as ‘draw()’ that must be implemented; Python will then raise an
exception for classes that don’t define the method.  Note that the
exception is only raised when you actually try to create an instance of
a subclass lacking the method:

     >>> class Circle(Drawable):
     ...     pass
     ...
     >>> c = Circle()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: Can't instantiate abstract class Circle with abstract methods draw
     >>>

Abstract data attributes can be declared using the ‘@abstractproperty’
decorator:

     from abc import abstractproperty
     ...

     @abstractproperty
     def readonly(self):
        return self._x

Subclasses must then define a ‘readonly’ property.

See also
........

PEP 3119(1) - Introducing Abstract Base Classes

     PEP written by Guido van Rossum and Talin.  Implemented by Guido
     van Rossum.  Backported to 2.6 by Benjamin Aranguren, with Alex
     Martelli.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3119/


File: python.info,  Node: PEP 3127 Integer Literal Support and Syntax,  Next: PEP 3129 Class Decorators,  Prev: PEP 3119 Abstract Base Classes,  Up: What’s New in Python 2 6

1.16.14 PEP 3127: Integer Literal Support and Syntax
----------------------------------------------------

Python 3.0 changes the syntax for octal (base-8) integer literals,
prefixing them with “0o” or “0O” instead of a leading zero, and adds
support for binary (base-2) integer literals, signalled by a “0b” or
“0B” prefix.

Python 2.6 doesn’t drop support for a leading 0 signalling an octal
number, but it does add support for “0o” and “0b”:

     >>> 0o21, 2*8 + 1
     (17, 17)
     >>> 0b101111
     47

The *note oct(): 1316. builtin still returns numbers prefixed with a
leading zero, and a new *note bin(): 12f0. builtin returns the binary
representation for a number:

     >>> oct(42)
     '052'
     >>> future_builtins.oct(42)
     '0o52'
     >>> bin(173)
     '0b10101101'

The *note int(): 257. and ‘long()’ builtins will now accept the “0o” and
“0b” prefixes when base-8 or base-2 are requested, or when the 'base'
argument is zero (signalling that the base used should be determined
from the string):

     >>> int ('0o52', 0)
     42
     >>> int('1101', 2)
     13
     >>> int('0b1101', 2)
     13
     >>> int('0b1101', 0)
     13

See also
........

PEP 3127(1) - Integer Literal Support and Syntax

     PEP written by Patrick Maupin; backported to 2.6 by Eric Smith.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3127/


File: python.info,  Node: PEP 3129 Class Decorators,  Next: PEP 3141 A Type Hierarchy for Numbers,  Prev: PEP 3127 Integer Literal Support and Syntax,  Up: What’s New in Python 2 6

1.16.15 PEP 3129: Class Decorators
----------------------------------

Decorators have been extended from functions to classes.  It’s now legal
to write:

     @foo
     @bar
     class A:
       pass

This is equivalent to:

     class A:
       pass

     A = foo(bar(A))

See also
........

PEP 3129(1) - Class Decorators

     PEP written by Collin Winter.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3129/


File: python.info,  Node: PEP 3141 A Type Hierarchy for Numbers,  Next: Other Language Changes<15>,  Prev: PEP 3129 Class Decorators,  Up: What’s New in Python 2 6

1.16.16 PEP 3141: A Type Hierarchy for Numbers
----------------------------------------------

Python 3.0 adds several abstract base classes for numeric types inspired
by Scheme’s numeric tower.  These classes were backported to 2.6 as the
*note numbers: 9e. module.

The most general ABC is ‘Number’.  It defines no operations at all, and
only exists to allow checking if an object is a number by doing
‘isinstance(obj, Number)’.

‘Complex’ is a subclass of ‘Number’.  Complex numbers can undergo the
basic operations of addition, subtraction, multiplication, division, and
exponentiation, and you can retrieve the real and imaginary parts and
obtain a number’s conjugate.  Python’s built-in complex type is an
implementation of ‘Complex’.

‘Real’ further derives from ‘Complex’, and adds operations that only
work on real numbers: ‘floor()’, ‘trunc()’, rounding, taking the
remainder mod N, floor division, and comparisons.

‘Rational’ numbers derive from ‘Real’, have ‘numerator’ and
‘denominator’ properties, and can be converted to floats.  Python 2.6
adds a simple rational-number class, ‘Fraction’, in the *note fractions:
5d. module.  (It’s called ‘Fraction’ instead of ‘Rational’ to avoid a
name clash with *note numbers.Rational: 1306.)

‘Integral’ numbers derive from ‘Rational’, and can be shifted left and
right with ‘<<’ and ‘>>’, combined using bitwise operations such as ‘&’
and ‘|’, and can be used as array indexes and slice boundaries.

In Python 3.0, the PEP slightly redefines the existing builtins *note
round(): 1322, *note math.floor(): 140a, *note math.ceil(): 140b, and
adds a new one, *note math.trunc(): 140c, that’s been backported to
Python 2.6.  ‘math.trunc()’ rounds toward zero, returning the closest
‘Integral’ that’s between the function’s argument and zero.

See also
........

PEP 3141(1) - A Type Hierarchy for Numbers

     PEP written by Jeffrey Yasskin.

Scheme's numerical tower(2), from the Guile manual.

Scheme's number datatypes(3) from the R5RS Scheme specification.

* Menu:

* The fractions Module::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3141/

   (2) 
https://www.gnu.org/software/guile/manual/html_node/Numerical-Tower.html#Numerical-Tower

   (3) 
https://conservatory.scheme.org/schemers/Documents/Standards/R5RS/HTML/r5rs-Z-H-9.html#%_sec_6.2


File: python.info,  Node: The fractions Module,  Up: PEP 3141 A Type Hierarchy for Numbers

1.16.16.1 The ‘fractions’ Module
................................

To fill out the hierarchy of numeric types, the *note fractions: 5d.
module provides a rational-number class.  Rational numbers store their
values as a numerator and denominator forming a fraction, and can
exactly represent numbers such as ‘2/3’ that floating-point numbers can
only approximate.

The ‘Fraction’ constructor takes two ‘Integral’ values that will be the
numerator and denominator of the resulting fraction.

     >>> from fractions import Fraction
     >>> a = Fraction(2, 3)
     >>> b = Fraction(2, 5)
     >>> float(a), float(b)
     (0.66666666666666663, 0.40000000000000002)
     >>> a+b
     Fraction(16, 15)
     >>> a/b
     Fraction(5, 3)

For converting floating-point numbers to rationals, the float type now
has an ‘as_integer_ratio()’ method that returns the numerator and
denominator for a fraction that evaluates to the same floating-point
value:

     >>> (2.5) .as_integer_ratio()
     (5, 2)
     >>> (3.1415) .as_integer_ratio()
     (7074029114692207L, 2251799813685248L)
     >>> (1./3) .as_integer_ratio()
     (6004799503160661L, 18014398509481984L)

Note that values that can only be approximated by floating-point
numbers, such as 1./3, are not simplified to the number being
approximated; the fraction attempts to match the floating-point value
'exactly'.

The *note fractions: 5d. module is based upon an implementation by
Sjoerd Mullender that was in Python’s ‘Demo/classes/’ directory for a
long time.  This implementation was significantly updated by Jeffrey
Yasskin.


File: python.info,  Node: Other Language Changes<15>,  Next: New and Improved Modules<2>,  Prev: PEP 3141 A Type Hierarchy for Numbers,  Up: What’s New in Python 2 6

1.16.17 Other Language Changes
------------------------------

Some smaller changes made to the core Python language are:

   * Directories and zip archives containing a ‘__main__.py’ file can
     now be executed directly by passing their name to the interpreter.
     The directory or zip archive is automatically inserted as the first
     entry in sys.path.  (Suggestion and initial patch by Andy Chu,
     subsequently revised by Phillip J. Eby and Nick Coghlan;
     bpo-1739468(1).)

   * The *note hasattr(): 4d5. function was catching and ignoring all
     errors, under the assumption that they meant a ‘__getattr__()’
     method was failing somehow and the return value of ‘hasattr()’
     would therefore be ‘False’.  This logic shouldn’t be applied to
     *note KeyboardInterrupt: 9dc. and *note SystemExit: d69, however;
     Python 2.6 will no longer discard such exceptions when ‘hasattr()’
     encounters them.  (Fixed by Benjamin Peterson; bpo-2196(2).)

   * When calling a function using the ‘**’ syntax to provide keyword
     arguments, you are no longer required to use a Python dictionary;
     any mapping will now work:

          >>> def f(**kw):
          ...    print sorted(kw)
          ...
          >>> ud=UserDict.UserDict()
          >>> ud['a'] = 1
          >>> ud['b'] = 'string'
          >>> f(**ud)
          ['a', 'b']

     (Contributed by Alexander Belopolsky; bpo-1686487(3).)

     It’s also become legal to provide keyword arguments after a ‘*args’
     argument to a function call.

          >>> def f(*args, **kw):
          ...     print args, kw
          ...
          >>> f(1,2,3, *(4,5,6), keyword=13)
          (1, 2, 3, 4, 5, 6) {'keyword': 13}

     Previously this would have been a syntax error.  (Contributed by
     Amaury Forgeot d’Arc; bpo-3473(4).)

   * A new builtin, ‘next(iterator, [default])’ returns the next item
     from the specified iterator.  If the 'default' argument is
     supplied, it will be returned if 'iterator' has been exhausted;
     otherwise, the *note StopIteration: c1b. exception will be raised.
     (Backported in bpo-2719(5).)

   * Tuples now have *note index(): 140f. and *note count(): 1410.
     methods matching the list type’s *note index(): 1411. and *note
     count(): 1412. methods:

          >>> t = (0,1,2,3,4,0,1,2)
          >>> t.index(3)
          3
          >>> t.count(0)
          2

     (Contributed by Raymond Hettinger)

   * The built-in types now have improved support for extended slicing
     syntax, accepting various combinations of ‘(start, stop, step)’.
     Previously, the support was partial and certain corner cases
     wouldn’t work.  (Implemented by Thomas Wouters.)

   * Properties now have three attributes, ‘getter’, ‘setter’ and
     ‘deleter’, that are decorators providing useful shortcuts for
     adding a getter, setter or deleter function to an existing
     property.  You would use them like this:

          class C(object):
              @property
              def x(self):
                  return self._x

              @x.setter
              def x(self, value):
                  self._x = value

              @x.deleter
              def x(self):
                  del self._x

          class D(C):
              @C.x.getter
              def x(self):
                  return self._x * 2

              @x.setter
              def x(self, value):
                  self._x = value / 2

   * Several methods of the built-in set types now accept multiple
     iterables: ‘intersection()’, ‘intersection_update()’, ‘union()’,
     ‘update()’, ‘difference()’ and ‘difference_update()’.

          >>> s=set('1234567890')
          >>> s.intersection('abc123', 'cdf246')  # Intersection between all inputs
          set(['2'])
          >>> s.difference('246', '789')
          set(['1', '0', '3', '5'])

     (Contributed by Raymond Hettinger.)

   * Many floating-point features were added.  The *note float(): 2f7.
     function will now turn the string ‘nan’ into an IEEE 754 Not A
     Number value, and ‘+inf’ and ‘-inf’ into positive or negative
     infinity.  This works on any platform with IEEE 754 semantics.
     (Contributed by Christian Heimes; bpo-1635(6).)

     Other functions in the *note math: 8e. module, ‘isinf()’ and
     ‘isnan()’, return true if their floating-point argument is infinite
     or Not A Number.  (bpo-1640(7))

     Conversion functions were added to convert floating-point numbers
     into hexadecimal strings (bpo-3008(8)).  These functions convert
     floats to and from a string representation without introducing
     rounding errors from the conversion between decimal and binary.
     Floats have a *note hex(): 1317. method that returns a string
     representation, and the ‘float.fromhex()’ method converts a string
     back into a number:

          >>> a = 3.75
          >>> a.hex()
          '0x1.e000000000000p+1'
          >>> float.fromhex('0x1.e000000000000p+1')
          3.75
          >>> b=1./3
          >>> b.hex()
          '0x1.5555555555555p-2'

   * A numerical nicety: when creating a complex number from two floats
     on systems that support signed zeros (-0 and +0), the *note
     complex(): 2f8. constructor will now preserve the sign of the zero.
     (Fixed by Mark T. Dickinson; bpo-1507(9).)

   * Classes that inherit a ‘__hash__()’ method from a parent class can
     set ‘__hash__ = None’ to indicate that the class isn’t hashable.
     This will make ‘hash(obj)’ raise a *note TypeError: 2c3. and the
     class will not be indicated as implementing the ‘Hashable’ ABC.

     You should do this when you’ve defined a ‘__cmp__()’ or ‘__eq__()’
     method that compares objects by their value rather than by
     identity.  All objects have a default hash method that uses
     ‘id(obj)’ as the hash value.  There’s no tidy way to remove the
     ‘__hash__()’ method inherited from a parent class, so assigning
     ‘None’ was implemented as an override.  At the C level, extensions
     can set ‘tp_hash’ to *note PyObject_HashNotImplemented(): 1413.
     (Fixed by Nick Coghlan and Amaury Forgeot d’Arc; bpo-2235(10).)

   * The *note GeneratorExit: 1414. exception now subclasses *note
     BaseException: 5be. instead of *note Exception: 9e5.  This means
     that an exception handler that does ‘except Exception:’ will not
     inadvertently catch ‘GeneratorExit’.  (Contributed by Chad Austin;
     bpo-1537(11).)

   * Generator objects now have a ‘gi_code’ attribute that refers to the
     original code object backing the generator.  (Contributed by Collin
     Winter; bpo-1473257(12).)

   * The *note compile(): 192. built-in function now accepts keyword
     arguments as well as positional parameters.  (Contributed by Thomas
     Wouters; bpo-1444529(13).)

   * The *note complex(): 2f8. constructor now accepts strings
     containing parenthesized complex numbers, meaning that
     ‘complex(repr(cplx))’ will now round-trip values.  For example,
     ‘complex('(3+4j)')’ now returns the value (3+4j).
     (bpo-1491866(14))

   * The string ‘translate()’ method now accepts ‘None’ as the
     translation table parameter, which is treated as the identity
     transformation.  This makes it easier to carry out operations that
     only delete characters.  (Contributed by Bengt Richter and
     implemented by Raymond Hettinger; bpo-1193128(15).)

   * The built-in *note dir(): 635. function now checks for a
     ‘__dir__()’ method on the objects it receives.  This method must
     return a list of strings containing the names of valid attributes
     for the object, and lets the object control the value that ‘dir()’
     produces.  Objects that have ‘__getattr__()’ or
     ‘__getattribute__()’ methods can use this to advertise
     pseudo-attributes they will honor.  (bpo-1591665(16))

   * Instance method objects have new attributes for the object and
     function comprising the method; the new synonym for ‘im_self’ is
     *note __self__: 1415, and ‘im_func’ is also available as *note
     __func__: 1345.  The old names are still supported in Python 2.6,
     but are gone in 3.0.

   * An obscure change: when you use the *note locals(): 141. function
     inside a *note class: 131f. statement, the resulting dictionary no
     longer returns free variables.  (Free variables, in this case, are
     variables referenced in the ‘class’ statement that aren’t
     attributes of the class.)

* Menu:

* Optimizations: Optimizations<14>.
* Interpreter Changes: Interpreter Changes<2>.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1739468

   (2) https://bugs.python.org/issue?@action=redirect&bpo=2196

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1686487

   (4) https://bugs.python.org/issue?@action=redirect&bpo=3473

   (5) https://bugs.python.org/issue?@action=redirect&bpo=2719

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1635

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1640

   (8) https://bugs.python.org/issue?@action=redirect&bpo=3008

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1507

   (10) https://bugs.python.org/issue?@action=redirect&bpo=2235

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1537

   (12) https://bugs.python.org/issue?@action=redirect&bpo=1473257

   (13) https://bugs.python.org/issue?@action=redirect&bpo=1444529

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1491866

   (15) https://bugs.python.org/issue?@action=redirect&bpo=1193128

   (16) https://bugs.python.org/issue?@action=redirect&bpo=1591665


File: python.info,  Node: Optimizations<14>,  Next: Interpreter Changes<2>,  Up: Other Language Changes<15>

1.16.17.1 Optimizations
.......................

   * The *note warnings: 112. module has been rewritten in C. This makes
     it possible to invoke warnings from the parser, and may also make
     the interpreter’s startup faster.  (Contributed by Neal Norwitz and
     Brett Cannon; bpo-1631171(1).)

   * Type objects now have a cache of methods that can reduce the work
     required to find the correct method implementation for a particular
     class; once cached, the interpreter doesn’t need to traverse base
     classes to figure out the right method to call.  The cache is
     cleared if a base class or the class itself is modified, so the
     cache should remain correct even in the face of Python’s dynamic
     nature.  (Original optimization implemented by Armin Rigo, updated
     for Python 2.6 by Kevin Jacobs; bpo-1700288(2).)

     By default, this change is only applied to types that are included
     with the Python core.  Extension modules may not necessarily be
     compatible with this cache, so they must explicitly add *note
     Py_TPFLAGS_HAVE_VERSION_TAG: 1417. to the module’s ‘tp_flags’ field
     to enable the method cache.  (To be compatible with the method
     cache, the extension module’s code must not directly access and
     modify the ‘tp_dict’ member of any of the types it implements.
     Most modules don’t do this, but it’s impossible for the Python
     interpreter to determine that.  See bpo-1878(3) for some
     discussion.)

   * Function calls that use keyword arguments are significantly faster
     by doing a quick pointer comparison, usually saving the time of a
     full string comparison.  (Contributed by Raymond Hettinger, after
     an initial implementation by Antoine Pitrou; bpo-1819(4).)

   * All of the functions in the *note struct: d5. module have been
     rewritten in C, thanks to work at the Need For Speed sprint.
     (Contributed by Raymond Hettinger.)

   * Some of the standard built-in types now set a bit in their type
     objects.  This speeds up checking whether an object is a subclass
     of one of these types.  (Contributed by Neal Norwitz.)

   * Unicode strings now use faster code for detecting whitespace and
     line breaks; this speeds up the ‘split()’ method by about 25% and
     ‘splitlines()’ by 35%.  (Contributed by Antoine Pitrou.)  Memory
     usage is reduced by using pymalloc for the Unicode string’s data.

   * The ‘with’ statement now stores the *note __exit__(): 1349. method
     on the stack, producing a small speedup.  (Implemented by Jeffrey
     Yasskin.)

   * To reduce memory usage, the garbage collector will now clear
     internal free lists when garbage-collecting the highest generation
     of objects.  This may return memory to the operating system sooner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1631171

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1700288

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1878

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1819


File: python.info,  Node: Interpreter Changes<2>,  Prev: Optimizations<14>,  Up: Other Language Changes<15>

1.16.17.2 Interpreter Changes
.............................

Two command-line options have been reserved for use by other Python
implementations.  The *note -J: 141a. switch has been reserved for use
by Jython for Jython-specific options, such as switches that are passed
to the underlying JVM. *note -X: 176. has been reserved for options
specific to a particular implementation of Python such as CPython,
Jython, or IronPython.  If either option is used with Python 2.6, the
interpreter will report that the option isn’t currently used.

Python can now be prevented from writing ‘.pyc’ or ‘.pyo’ files by
supplying the *note -B: 141b. switch to the Python interpreter, or by
setting the *note PYTHONDONTWRITEBYTECODE: 141c. environment variable
before running the interpreter.  This setting is available to Python
programs as the ‘sys.dont_write_bytecode’ variable, and Python code can
change the value to modify the interpreter’s behaviour.  (Contributed by
Neal Norwitz and Georg Brandl.)

The encoding used for standard input, output, and standard error can be
specified by setting the *note PYTHONIOENCODING: 1045. environment
variable before running the interpreter.  The value should be a string
in the form ‘<encoding>’ or ‘<encoding>:<errorhandler>’.  The 'encoding'
part specifies the encoding’s name, e.g.  ‘utf-8’ or ‘latin-1’; the
optional 'errorhandler' part specifies what to do with characters that
can’t be handled by the encoding, and should be one of “error”,
“ignore”, or “replace”.  (Contributed by Martin von Löwis.)


File: python.info,  Node: New and Improved Modules<2>,  Next: Deprecations and Removals,  Prev: Other Language Changes<15>,  Up: What’s New in Python 2 6

1.16.18 New and Improved Modules
--------------------------------

As in every release, Python’s standard library received a number of
enhancements and bug fixes.  Here’s a partial list of the most notable
changes, sorted alphabetically by module name.  Consult the ‘Misc/NEWS’
file in the source tree for a more complete list of changes, or look
through the Subversion logs for all the details.

   * The ‘asyncore’ and ‘asynchat’ modules are being actively maintained
     again, and a number of patches and bugfixes were applied.
     (Maintained by Josiah Carlson; see bpo-1736190(1) for one patch.)

   * The ‘bsddb’ module also has a new maintainer, Jesús Cea Avión, and
     the package is now available as a standalone package.  The web page
     for the package is www.jcea.es/programacion/pybsddb.htm(2).  The
     plan is to remove the package from the standard library in Python
     3.0, because its pace of releases is much more frequent than
     Python’s.

     The ‘bsddb.dbshelve’ module now uses the highest pickling protocol
     available, instead of restricting itself to protocol 1.
     (Contributed by W. Barnes.)

   * The ‘cgi’ module will now read variables from the query string of
     an HTTP POST request.  This makes it possible to use form actions
     with URLs that include query strings such as
     “/cgi-bin/add.py?category=1”.  (Contributed by Alexandre Fiori and
     Nubis; bpo-1817(3).)

     The ‘parse_qs()’ and ‘parse_qsl()’ functions have been relocated
     from the ‘cgi’ module to the *note urlparse: 10a. module.  The
     versions still available in the ‘cgi’ module will trigger *note
     PendingDeprecationWarning: 8d1. messages in 2.6 (bpo-600362(4)).

   * The *note cmath: 18. module underwent extensive revision,
     contributed by Mark Dickinson and Christian Heimes.  Five new
     functions were added:

        * ‘polar()’ converts a complex number to polar form, returning
          the modulus and argument of the complex number.

        * ‘rect()’ does the opposite, turning a modulus, argument pair
          back into the corresponding complex number.

        * ‘phase()’ returns the argument (also called the angle) of a
          complex number.

        * ‘isnan()’ returns True if either the real or imaginary part of
          its argument is a NaN.

        * ‘isinf()’ returns True if either the real or imaginary part of
          its argument is infinite.

     The revisions also improved the numerical soundness of the *note
     cmath: 18. module.  For all functions, the real and imaginary parts
     of the results are accurate to within a few units of least
     precision (ulps) whenever possible.  See bpo-1381(5) for the
     details.  The branch cuts for ‘asinh()’, ‘atanh()’: and ‘atan()’
     have also been corrected.

     The tests for the module have been greatly expanded; nearly 2000
     new test cases exercise the algebraic functions.

     On IEEE 754 platforms, the *note cmath: 18. module now handles IEEE
     754 special values and floating-point exceptions in a manner
     consistent with Annex ‘G’ of the C99 standard.

   * A new data type in the *note collections: 1d. module:
     ‘namedtuple(typename, fieldnames)’ is a factory function that
     creates subclasses of the standard tuple whose fields are
     accessible by name as well as index.  For example:

          >>> var_type = collections.namedtuple('variable',
          ...             'id name type size')
          >>> # Names are separated by spaces or commas.
          >>> # 'id, name, type, size' would also work.
          >>> var_type._fields
          ('id', 'name', 'type', 'size')

          >>> var = var_type(1, 'frequency', 'int', 4)
          >>> print var[0], var.id    # Equivalent
          1 1
          >>> print var[2], var.type  # Equivalent
          int int
          >>> var._asdict()
          {'size': 4, 'type': 'int', 'id': 1, 'name': 'frequency'}
          >>> v2 = var._replace(name='amplitude')
          >>> v2
          variable(id=1, name='amplitude', type='int', size=4)

     Several places in the standard library that returned tuples have
     been modified to return ‘namedtuple()’ instances.  For example, the
     ‘Decimal.as_tuple()’ method now returns a named tuple with ‘sign’,
     ‘digits’, and ‘exponent’ fields.

     (Contributed by Raymond Hettinger.)

   * Another change to the *note collections: 1d. module is that the
     ‘deque’ type now supports an optional 'maxlen' parameter; if
     supplied, the deque’s size will be restricted to no more than
     'maxlen' items.  Adding more items to a full deque causes old items
     to be discarded.

          >>> from collections import deque
          >>> dq=deque(maxlen=3)
          >>> dq
          deque([], maxlen=3)
          >>> dq.append(1); dq.append(2); dq.append(3)
          >>> dq
          deque([1, 2, 3], maxlen=3)
          >>> dq.append(4)
          >>> dq
          deque([2, 3, 4], maxlen=3)

     (Contributed by Raymond Hettinger.)

   * The *note Cookie: 71. module’s *note Morsel: c24. objects now
     support an *note httponly: 141e. attribute.  In some browsers.
     cookies with this attribute set cannot be accessed or manipulated
     by JavaScript code.  (Contributed by Arvin Schnell;
     bpo-1638033(6).)

   * A new window method in the *note curses: 2b. module, ‘chgat()’,
     changes the display attributes for a certain number of characters
     on a single line.  (Contributed by Fabian Kreutz.)

          # Boldface text starting at y=0,x=21
          # and affecting the rest of the line.
          stdscr.chgat(0, 21, curses.A_BOLD)

     The ‘Textbox’ class in the *note curses.textpad: 2e. module now
     supports editing in insert mode as well as overwrite mode.  Insert
     mode is enabled by supplying a true value for the 'insert_mode'
     parameter when creating the ‘Textbox’ instance.

   * The *note datetime: 30. module’s ‘strftime()’ methods now support a
     ‘%f’ format code that expands to the number of microseconds in the
     object, zero-padded on the left to six places.  (Contributed by
     Skip Montanaro; bpo-1158(7).)

   * The *note decimal: 36. module was updated to version 1.66 of the
     General Decimal Specification(8).  New features include some
     methods for some basic mathematical functions such as ‘exp()’ and
     ‘log10()’:

          >>> Decimal(1).exp()
          Decimal("2.718281828459045235360287471")
          >>> Decimal("2.7182818").ln()
          Decimal("0.9999999895305022877376682436")
          >>> Decimal(1000).log10()
          Decimal("3")

     The ‘as_tuple()’ method of ‘Decimal’ objects now returns a named
     tuple with ‘sign’, ‘digits’, and ‘exponent’ fields.

     (Implemented by Facundo Batista and Mark Dickinson.  Named tuple
     support added by Raymond Hettinger.)

   * The *note difflib: 37. module’s ‘SequenceMatcher’ class now returns
     named tuples representing matches, with ‘a’, ‘b’, and ‘size’
     attributes.  (Contributed by Raymond Hettinger.)

   * An optional ‘timeout’ parameter, specifying a timeout measured in
     seconds, was added to the *note ftplib.FTP: 903. class constructor
     as well as the ‘connect()’ method.  (Added by Facundo Batista.)
     Also, the ‘FTP’ class’s ‘storbinary()’ and ‘storlines()’ now take
     an optional 'callback' parameter that will be called with each
     block of data after the data has been sent.  (Contributed by Phil
     Schwartz; bpo-1221598(9).)

   * The ‘reduce()’ built-in function is also available in the *note
     functools: 5f. module.  In Python 3.0, the builtin has been dropped
     and ‘reduce()’ is only available from ‘functools’; currently there
     are no plans to drop the builtin in the 2.x series.  (Patched by
     Christian Heimes; bpo-1739906(10).)

   * When possible, the *note getpass: 62. module will now use
     ‘/dev/tty’ to print a prompt message and read the password, falling
     back to standard error and standard input.  If the password may be
     echoed to the terminal, a warning is printed before the prompt is
     displayed.  (Contributed by Gregory P. Smith.)

   * The *note glob.glob(): 29f. function can now return Unicode
     filenames if a Unicode path was used and Unicode filenames are
     matched within the directory.  (bpo-1001604(11))

   * A new function in the *note heapq: 69. module, ‘merge(iter1, iter2,
     ...)’, takes any number of iterables returning data in sorted
     order, and returns a new generator that returns the contents of all
     the iterators, also in sorted order.  For example:

          >>> list(heapq.merge([1, 3, 5, 9], [2, 8, 16]))
          [1, 2, 3, 5, 8, 9, 16]

     Another new function, ‘heappushpop(heap, item)’, pushes 'item' onto
     'heap', then pops off and returns the smallest item.  This is more
     efficient than making a call to ‘heappush()’ and then ‘heappop()’.

     *note heapq: 69. is now implemented to only use less-than
     comparison, instead of the less-than-or-equal comparison it
     previously used.  This makes ‘heapq’’s usage of a type match the
     *note list.sort(): bee. method.  (Contributed by Raymond
     Hettinger.)

   * An optional ‘timeout’ parameter, specifying a timeout measured in
     seconds, was added to the *note httplib.HTTPConnection: b59. and
     *note HTTPSConnection: b5a. class constructors.  (Added by Facundo
     Batista.)

   * Most of the *note inspect: 7e. module’s functions, such as
     ‘getmoduleinfo()’ and ‘getargs()’, now return named tuples.  In
     addition to behaving like tuples, the elements of the return value
     can also be accessed as attributes.  (Contributed by Raymond
     Hettinger.)

     Some new functions in the module include ‘isgenerator()’,
     ‘isgeneratorfunction()’, and ‘isabstract()’.

   * The *note itertools: 81. module gained several new functions.

     ‘izip_longest(iter1, iter2, ...[, fillvalue])’ makes tuples from
     each of the elements; if some of the iterables are shorter than
     others, the missing values are set to 'fillvalue'.  For example:

          >>> tuple(itertools.izip_longest([1,2,3], [1,2,3,4,5]))
          ((1, 1), (2, 2), (3, 3), (None, 4), (None, 5))

     ‘product(iter1, iter2, ..., [repeat=N])’ returns the Cartesian
     product of the supplied iterables, a set of tuples containing every
     possible combination of the elements returned from each iterable.

          >>> list(itertools.product([1,2,3], [4,5,6]))
          [(1, 4), (1, 5), (1, 6),
           (2, 4), (2, 5), (2, 6),
           (3, 4), (3, 5), (3, 6)]

     The optional 'repeat' keyword argument is used for taking the
     product of an iterable or a set of iterables with themselves,
     repeated 'N' times.  With a single iterable argument, 'N'-tuples
     are returned:

          >>> list(itertools.product([1,2], repeat=3))
          [(1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 2),
           (2, 1, 1), (2, 1, 2), (2, 2, 1), (2, 2, 2)]

     With two iterables, '2N'-tuples are returned.

          >>> list(itertools.product([1,2], [3,4], repeat=2))
          [(1, 3, 1, 3), (1, 3, 1, 4), (1, 3, 2, 3), (1, 3, 2, 4),
           (1, 4, 1, 3), (1, 4, 1, 4), (1, 4, 2, 3), (1, 4, 2, 4),
           (2, 3, 1, 3), (2, 3, 1, 4), (2, 3, 2, 3), (2, 3, 2, 4),
           (2, 4, 1, 3), (2, 4, 1, 4), (2, 4, 2, 3), (2, 4, 2, 4)]

     ‘combinations(iterable, r)’ returns sub-sequences of length 'r'
     from the elements of 'iterable'.

          >>> list(itertools.combinations('123', 2))
          [('1', '2'), ('1', '3'), ('2', '3')]
          >>> list(itertools.combinations('123', 3))
          [('1', '2', '3')]
          >>> list(itertools.combinations('1234', 3))
          [('1', '2', '3'), ('1', '2', '4'),
           ('1', '3', '4'), ('2', '3', '4')]

     ‘permutations(iter[, r])’ returns all the permutations of length
     'r' of the iterable’s elements.  If 'r' is not specified, it will
     default to the number of elements produced by the iterable.

          >>> list(itertools.permutations([1,2,3,4], 2))
          [(1, 2), (1, 3), (1, 4),
           (2, 1), (2, 3), (2, 4),
           (3, 1), (3, 2), (3, 4),
           (4, 1), (4, 2), (4, 3)]

     ‘itertools.chain(*iterables)’ is an existing function in *note
     itertools: 81. that gained a new constructor in Python 2.6.
     ‘itertools.chain.from_iterable(iterable)’ takes a single iterable
     that should return other iterables.  ‘chain()’ will then return all
     the elements of the first iterable, then all the elements of the
     second, and so on.

          >>> list(itertools.chain.from_iterable([[1,2,3], [4,5,6]]))
          [1, 2, 3, 4, 5, 6]

     (All contributed by Raymond Hettinger.)

   * The *note logging: 87. module’s ‘FileHandler’ class and its
     subclasses ‘WatchedFileHandler’, ‘RotatingFileHandler’, and
     ‘TimedRotatingFileHandler’ now have an optional 'delay' parameter
     to their constructors.  If 'delay' is true, opening of the log file
     is deferred until the first ‘emit()’ call is made.  (Contributed by
     Vinay Sajip.)

     ‘TimedRotatingFileHandler’ also has a 'utc' constructor parameter.
     If the argument is true, UTC time will be used in determining when
     midnight occurs and in generating filenames; otherwise local time
     will be used.

   * Several new functions were added to the *note math: 8e. module:

        * *note isinf(): 141f. and *note isnan(): 1420. determine
          whether a given float is a (positive or negative) infinity or
          a NaN (Not a Number), respectively.

        * *note copysign(): 1421. copies the sign bit of an IEEE 754
          number, returning the absolute value of 'x' combined with the
          sign bit of 'y'.  For example, ‘math.copysign(1, -0.0)’
          returns -1.0.  (Contributed by Christian Heimes.)

        * *note factorial(): 951. computes the factorial of a number.
          (Contributed by Raymond Hettinger; bpo-2138(12).)

        * *note fsum(): 1422. adds up the stream of numbers from an
          iterable, and is careful to avoid loss of precision through
          using partial sums.  (Contributed by Jean Brouwers, Raymond
          Hettinger, and Mark Dickinson; bpo-2819(13).)

        * *note acosh(): 1423, *note asinh(): 1424. and *note atanh():
          1425. compute the inverse hyperbolic functions.

        * *note log1p(): 1426. returns the natural logarithm of '1+x'
          (base 'e').

        * ‘trunc()’ rounds a number toward zero, returning the closest
          ‘Integral’ that’s between the function’s argument and zero.
          Added as part of the backport of *note PEP 3141's type
          hierarchy for numbers: 1305.

   * The *note math: 8e. module has been improved to give more
     consistent behaviour across platforms, especially with respect to
     handling of floating-point exceptions and IEEE 754 special values.

     Whenever possible, the module follows the recommendations of the
     C99 standard about 754’s special values.  For example, ‘sqrt(-1.)’
     should now give a *note ValueError: 202. across almost all
     platforms, while ‘sqrt(float('NaN'))’ should return a NaN on all
     IEEE 754 platforms.  Where Annex ‘F’ of the C99 standard recommends
     signaling ‘divide-by-zero’ or ‘invalid’, Python will raise
     ‘ValueError’.  Where Annex ‘F’ of the C99 standard recommends
     signaling ‘overflow’, Python will raise *note OverflowError: 888.
     (See bpo-711019(14) and bpo-1640(15).)

     (Contributed by Christian Heimes and Mark Dickinson.)

   * *note mmap: 20b. objects now have a ‘rfind()’ method that searches
     for a substring beginning at the end of the string and searching
     backwards.  The ‘find()’ method also gained an 'end' parameter
     giving an index at which to stop searching.  (Contributed by John
     Lenton.)

   * The *note operator: 9f. module gained a ‘methodcaller()’ function
     that takes a name and an optional set of arguments, returning a
     callable that will call the named function on any arguments passed
     to it.  For example:

          >>> # Equivalent to lambda s: s.replace('old', 'new')
          >>> replacer = operator.methodcaller('replace', 'old', 'new')
          >>> replacer('old wine in old bottles')
          'new wine in new bottles'

     (Contributed by Georg Brandl, after a suggestion by Gregory
     Petrosyan.)

     The ‘attrgetter()’ function now accepts dotted names and performs
     the corresponding attribute lookups:

          >>> inst_name = operator.attrgetter(
          ...        '__class__.__name__')
          >>> inst_name('')
          'str'
          >>> inst_name(help)
          '_Helper'

     (Contributed by Georg Brandl, after a suggestion by Barry Warsaw.)

   * The *note os: a1. module now wraps several new system calls.
     ‘fchmod(fd, mode)’ and ‘fchown(fd, uid, gid)’ change the mode and
     ownership of an opened file, and ‘lchmod(path, mode)’ changes the
     mode of a symlink.  (Contributed by Georg Brandl and Christian
     Heimes.)

     ‘chflags()’ and ‘lchflags()’ are wrappers for the corresponding
     system calls (where they’re available), changing the flags set on a
     file.  Constants for the flag values are defined in the *note stat:
     d1. module; some possible values include ‘UF_IMMUTABLE’ to signal
     the file may not be changed and ‘UF_APPEND’ to indicate that data
     can only be appended to the file.  (Contributed by M. Levinson.)

     ‘os.closerange(low, high)’ efficiently closes all file descriptors
     from 'low' to 'high', ignoring any errors and not including 'high'
     itself.  This function is now used by the *note subprocess: d6.
     module to make starting processes faster.  (Contributed by Georg
     Brandl; bpo-1663329(16).)

   * The ‘os.environ’ object’s ‘clear()’ method will now unset the
     environment variables using *note os.unsetenv(): 924. in addition
     to clearing the object’s keys.  (Contributed by Martin Horcicka;
     bpo-1181(17).)

   * The *note os.walk(): 4ac. function now has a ‘followlinks’
     parameter.  If set to True, it will follow symlinks pointing to
     directories and visit the directory’s contents.  For backward
     compatibility, the parameter’s default value is false.  Note that
     the function can fall into an infinite recursion if there’s a
     symlink that points to a parent directory.  (bpo-1273829(18))

   * In the *note os.path: a2. module, the ‘splitext()’ function has
     been changed to not split on leading period characters.  This
     produces better results when operating on Unix’s dot-files.  For
     example, ‘os.path.splitext('.ipython')’ now returns ‘('.ipython',
     '')’ instead of ‘('', '.ipython')’.  (bpo-1115886(19))

     A new function, ‘os.path.relpath(path, start='.')’, returns a
     relative path from the ‘start’ path, if it’s supplied, or from the
     current working directory to the destination ‘path’.  (Contributed
     by Richard Barran; bpo-1339796(20).)

     On Windows, *note os.path.expandvars(): 1427. will now expand
     environment variables given in the form “%var%”, and “~user” will
     be expanded into the user’s home directory path.  (Contributed by
     Josiah Carlson; bpo-957650(21).)

   * The Python debugger provided by the *note pdb: a5. module gained a
     new command: “run” restarts the Python program being debugged and
     can optionally take new command-line arguments for the program.
     (Contributed by Rocky Bernstein; bpo-1393667(22).)

   * The *note pdb.post_mortem(): 1428. function, used to begin
     debugging a traceback, will now use the traceback returned by *note
     sys.exc_info(): 68d. if no traceback is supplied.  (Contributed by
     Facundo Batista; bpo-1106316(23).)

   * The *note pickletools: a7. module now has an ‘optimize()’ function
     that takes a string containing a pickle and removes some unused
     opcodes, returning a shorter pickle that contains the same data
     structure.  (Contributed by Raymond Hettinger.)

   * A ‘get_data()’ function was added to the *note pkgutil: a9. module
     that returns the contents of resource files included with an
     installed Python package.  For example:

          >>> import pkgutil
          >>> print pkgutil.get_data('test', 'exception_hierarchy.txt')
          BaseException
           +-- SystemExit
           +-- KeyboardInterrupt
           +-- GeneratorExit
           +-- Exception
                +-- StopIteration
                +-- StandardError
           ...

     (Contributed by Paul Moore; bpo-2439(24).)

   * The ‘pyexpat’ module’s ‘Parser’ objects now allow setting their
     ‘buffer_size’ attribute to change the size of the buffer used to
     hold character data.  (Contributed by Achim Gaedke; bpo-1137(25).)

   * The ‘Queue’ module now provides queue variants that retrieve
     entries in different orders.  The ‘PriorityQueue’ class stores
     queued items in a heap and retrieves them in priority order, and
     ‘LifoQueue’ retrieves the most recently added entries first,
     meaning that it behaves like a stack.  (Contributed by Raymond
     Hettinger.)

   * The *note random: b8. module’s ‘Random’ objects can now be pickled
     on a 32-bit system and unpickled on a 64-bit system, and vice
     versa.  Unfortunately, this change also means that Python 2.6’s
     ‘Random’ objects can’t be unpickled correctly on earlier versions
     of Python.  (Contributed by Shawn Ligocki; bpo-1727780(26).)

     The new ‘triangular(low, high, mode)’ function returns random
     numbers following a triangular distribution.  The returned values
     are between 'low' and 'high', not including 'high' itself, and with
     'mode' as the most frequently occurring value in the distribution.
     (Contributed by Wladmir van der Laan and Raymond Hettinger;
     bpo-1681432(27).)

   * Long regular expression searches carried out by the *note re: b9.
     module will check for signals being delivered, so time-consuming
     searches can now be interrupted.  (Contributed by Josh Hoyt and
     Ralf Schmitt; bpo-846388(28).)

     The regular expression module is implemented by compiling bytecodes
     for a tiny regex-specific virtual machine.  Untrusted code could
     create malicious strings of bytecode directly and cause crashes, so
     Python 2.6 includes a verifier for the regex bytecode.
     (Contributed by Guido van Rossum from work for Google App Engine;
     bpo-3487(29).)

   * The *note rlcompleter: bd. module’s ‘Completer.complete()’ method
     will now ignore exceptions triggered while evaluating a name.
     (Fixed by Lorenz Quack; bpo-2250(30).)

   * The *note sched: bf. module’s ‘scheduler’ instances now have a
     read-only *note queue: b6. attribute that returns the contents of
     the scheduler’s queue, represented as a list of named tuples with
     the fields ‘(time, priority, action, argument)’.  (Contributed by
     Raymond Hettinger; bpo-1861(31).)

   * The *note select: c1. module now has wrapper functions for the
     Linux ‘epoll()’ and BSD ‘kqueue()’ system calls.  ‘modify()’ method
     was added to the existing ‘poll’ objects; ‘pollobj.modify(fd,
     eventmask)’ takes a file descriptor or file object and an event
     mask, modifying the recorded event mask for that file.
     (Contributed by Christian Heimes; bpo-1657(32).)

   * The *note shutil.copytree(): a36. function now has an optional
     'ignore' argument that takes a callable object.  This callable will
     receive each directory path and a list of the directory’s contents,
     and returns a list of names that will be ignored, not copied.

     The *note shutil: c5. module also provides an ‘ignore_patterns()’
     function for use with this new parameter.  ‘ignore_patterns()’
     takes an arbitrary number of glob-style patterns and returns a
     callable that will ignore any files and directories that match any
     of these patterns.  The following example copies a directory tree,
     but skips both ‘.svn’ directories and Emacs backup files, which
     have names ending with ‘~’:

          shutil.copytree('Doc/library', '/tmp/library',
                          ignore=shutil.ignore_patterns('*~', '.svn'))

     (Contributed by Tarek Ziadé; bpo-2663(33).)

   * Integrating signal handling with GUI handling event loops like
     those used by Tkinter or GTk+ has long been a problem; most
     software ends up polling, waking up every fraction of a second to
     check if any GUI events have occurred.  The *note signal: c6.
     module can now make this more efficient.  Calling
     ‘signal.set_wakeup_fd(fd)’ sets a file descriptor to be used; when
     a signal is received, a byte is written to that file descriptor.
     There’s also a C-level function, *note PySignal_SetWakeupFd():
     1429, for setting the descriptor.

     Event loops will use this by opening a pipe to create two
     descriptors, one for reading and one for writing.  The writable
     descriptor will be passed to ‘set_wakeup_fd()’, and the readable
     descriptor will be added to the list of descriptors monitored by
     the event loop via ‘select()’ or ‘poll()’.  On receiving a signal,
     a byte will be written and the main event loop will be woken up,
     avoiding the need to poll.

     (Contributed by Adam Olsen; bpo-1583(34).)

     The ‘siginterrupt()’ function is now available from Python code,
     and allows changing whether signals can interrupt system calls or
     not.  (Contributed by Ralf Schmitt.)

     The ‘setitimer()’ and ‘getitimer()’ functions have also been added
     (where they’re available).  ‘setitimer()’ allows setting interval
     timers that will cause a signal to be delivered to the process
     after a specified time, measured in wall-clock time, consumed
     process time, or combined process+system time.  (Contributed by
     Guilherme Polo; bpo-2240(35).)

   * The *note smtplib: ca. module now supports SMTP over SSL thanks to
     the addition of the ‘SMTP_SSL’ class.  This class supports an
     interface identical to the existing ‘SMTP’ class.  (Contributed by
     Monty Taylor.)  Both class constructors also have an optional
     ‘timeout’ parameter that specifies a timeout for the initial
     connection attempt, measured in seconds.  (Contributed by Facundo
     Batista.)

     An implementation of the LMTP protocol ( RFC 2033(36)) was also
     added to the module.  LMTP is used in place of SMTP when
     transferring e-mail between agents that don’t manage a mail queue.
     (LMTP implemented by Leif Hedstrom; bpo-957003(37).)

     ‘SMTP.starttls()’ now complies with RFC 3207(38) and forgets any
     knowledge obtained from the server not obtained from the TLS
     negotiation itself.  (Patch contributed by Bill Fenner;
     bpo-829951(39).)

   * The *note socket: cc. module now supports TIPC
     (‘https://tipc.sourceforge.net/’), a high-performance non-IP-based
     protocol designed for use in clustered environments.  TIPC
     addresses are 4- or 5-tuples.  (Contributed by Alberto Bertogli;
     bpo-1646(40).)

     A new function, ‘create_connection()’, takes an address and
     connects to it using an optional timeout value, returning the
     connected socket object.  This function also looks up the address’s
     type and connects to it using IPv4 or IPv6 as appropriate.
     Changing your code to use ‘create_connection()’ instead of
     ‘socket(socket.AF_INET, ...)’ may be all that’s required to make
     your code work with IPv6.

   * The base classes in the *note SocketServer: cd. module now support
     calling a *note handle_timeout(): 136b. method after a span of
     inactivity specified by the server’s *note timeout: 136a.
     attribute.  (Contributed by Michael Pomraning.)  The *note
     serve_forever(): 1183. method now takes an optional poll interval
     measured in seconds, controlling how often the server will check
     for a shutdown request.  (Contributed by Pedro Werneck and Jeffrey
     Yasskin; bpo-742598(41), bpo-1193577(42).)

   * The *note sqlite3: cf. module, maintained by Gerhard Häring, has
     been updated from version 2.3.2 in Python 2.5 to version 2.4.1.

   * The *note struct: d5. module now supports the C99 _Bool type, using
     the format character ‘'?'’.  (Contributed by David Remahl.)

   * The *note Popen: 199. objects provided by the *note subprocess: d6.
     module now have *note terminate(): 142a, *note kill(): 142b, and
     *note send_signal(): 142c. methods.  On Windows, ‘send_signal()’
     only supports the *note SIGTERM: 142d. signal, and all these
     methods are aliases for the Win32 API function
     ‘TerminateProcess()’.  (Contributed by Christian Heimes.)

   * A new variable in the *note sys: d9. module, ‘float_info’, is an
     object containing information derived from the ‘float.h’ file about
     the platform’s floating-point support.  Attributes of this object
     include ‘mant_dig’ (number of digits in the mantissa), ‘epsilon’
     (smallest difference between 1.0 and the next largest value
     representable), and several others.  (Contributed by Christian
     Heimes; bpo-1534(43).)

     Another new variable, ‘dont_write_bytecode’, controls whether
     Python writes any ‘.pyc’ or ‘.pyo’ files on importing a module.  If
     this variable is true, the compiled files are not written.  The
     variable is initially set on start-up by supplying the *note -B:
     141b. switch to the Python interpreter, or by setting the *note
     PYTHONDONTWRITEBYTECODE: 141c. environment variable before running
     the interpreter.  Python code can subsequently change the value of
     this variable to control whether bytecode files are written or not.
     (Contributed by Neal Norwitz and Georg Brandl.)

     Information about the command-line arguments supplied to the Python
     interpreter is available by reading attributes of a named tuple
     available as ‘sys.flags’.  For example, the ‘verbose’ attribute is
     true if Python was executed in verbose mode, ‘debug’ is true in
     debugging mode, etc.  These attributes are all read-only.
     (Contributed by Christian Heimes.)

     A new function, ‘getsizeof()’, takes a Python object and returns
     the amount of memory used by the object, measured in bytes.
     Built-in objects return correct results; third-party extensions may
     not, but can define a ‘__sizeof__()’ method to return the object’s
     size.  (Contributed by Robert Schuppenies; bpo-2898(44).)

     It’s now possible to determine the current profiler and tracer
     functions by calling *note sys.getprofile(): 142e. and *note
     sys.gettrace(): 142f.  (Contributed by Georg Brandl; bpo-1648(45).)

   * The *note tarfile: de. module now supports POSIX.1-2001 (pax)
     tarfiles in addition to the POSIX.1-1988 (ustar) and GNU tar
     formats that were already supported.  The default format is GNU
     tar; specify the ‘format’ parameter to open a file using a
     different format:

          tar = tarfile.open("output.tar", "w",
                             format=tarfile.PAX_FORMAT)

     The new ‘encoding’ and ‘errors’ parameters specify an encoding and
     an error handling scheme for character conversions.  ‘'strict'’,
     ‘'ignore'’, and ‘'replace'’ are the three standard ways Python can
     handle errors,; ‘'utf-8'’ is a special value that replaces bad
     characters with their UTF-8 representation.  (Character conversions
     occur because the PAX format supports Unicode filenames, defaulting
     to UTF-8 encoding.)

     The ‘TarFile.add()’ method now accepts an ‘exclude’ argument that’s
     a function that can be used to exclude certain filenames from an
     archive.  The function must take a filename and return true if the
     file should be excluded or false if it should be archived.  The
     function is applied to both the name initially passed to ‘add()’
     and to the names of files in recursively added directories.

     (All changes contributed by Lars Gustäbel).

   * An optional ‘timeout’ parameter was added to the ‘telnetlib.Telnet’
     class constructor, specifying a timeout measured in seconds.
     (Added by Facundo Batista.)

   * The *note tempfile.NamedTemporaryFile: 4c9. class usually deletes
     the temporary file it created when the file is closed.  This
     behaviour can now be changed by passing ‘delete=False’ to the
     constructor.  (Contributed by Damien Miller; bpo-1537850(46).)

     A new class, ‘SpooledTemporaryFile’, behaves like a temporary file
     but stores its data in memory until a maximum size is exceeded.  On
     reaching that limit, the contents will be written to an on-disk
     temporary file.  (Contributed by Dustin J. Mitchell.)

     The ‘NamedTemporaryFile’ and ‘SpooledTemporaryFile’ classes both
     work as context managers, so you can write ‘with
     tempfile.NamedTemporaryFile() as tmp: ...’.  (Contributed by
     Alexander Belopolsky; bpo-2021(47).)

   * The *note test.test_support: e4. module gained a number of context
     managers useful for writing tests.  *note EnvironmentVarGuard():
     1430. is a context manager that temporarily changes environment
     variables and automatically restores them to their old values.

     Another context manager, ‘TransientResource’, can surround calls to
     resources that may or may not be available; it will catch and
     ignore a specified list of exceptions.  For example, a network test
     may ignore certain failures when connecting to an external web
     site:

          with test_support.TransientResource(IOError,
                                          errno=errno.ETIMEDOUT):
              f = urllib.urlopen('https://sf.net')
              ...

     Finally, ‘check_warnings()’ resets the ‘warning’ module’s warning
     filters and returns an object that will record all warning messages
     triggered (bpo-3781(48)):

          with test_support.check_warnings() as wrec:
              warnings.simplefilter("always")
              # ... code that triggers a warning ...
              assert str(wrec.message) == "function is outdated"
              assert len(wrec.warnings) == 1, "Multiple warnings raised"

     (Contributed by Brett Cannon.)

   * The *note textwrap: ec. module can now preserve existing whitespace
     at the beginnings and ends of the newly created lines by specifying
     ‘drop_whitespace=False’ as an argument:

          >>> S = """This  sentence  has a bunch   of
          ...   extra   whitespace."""
          >>> print textwrap.fill(S, width=15)
          This  sentence
          has a bunch
          of    extra
          whitespace.
          >>> print textwrap.fill(S, drop_whitespace=False, width=15)
          This  sentence
            has a bunch
             of    extra
             whitespace.
          >>>

     (Contributed by Dwayne Bailey; bpo-1581073(49).)

   * The *note threading: ed. module API is being changed to use
     properties such as ‘daemon’ instead of ‘setDaemon()’ and
     ‘isDaemon()’ methods, and some methods have been renamed to use
     underscores instead of camel-case; for example, the ‘activeCount()’
     method is renamed to ‘active_count()’.  Both the 2.6 and 3.0
     versions of the module support the same properties and renamed
     methods, but don’t remove the old methods.  No date has been set
     for the deprecation of the old APIs in Python 3.x; the old APIs
     won’t be removed in any 2.x version.  (Carried out by several
     people, most notably Benjamin Peterson.)

     The *note threading: ed. module’s ‘Thread’ objects gained an
     ‘ident’ property that returns the thread’s identifier, a nonzero
     integer.  (Contributed by Gregory P. Smith; bpo-2871(50).)

   * The *note timeit: ef. module now accepts callables as well as
     strings for the statement being timed and for the setup code.  Two
     convenience functions were added for creating ‘Timer’ instances:
     ‘repeat(stmt, setup, time, repeat, number)’ and ‘timeit(stmt,
     setup, time, number)’ create an instance and call the corresponding
     method.  (Contributed by Erik Demaine; bpo-1533909(51).)

   * The ‘Tkinter’ module now accepts lists and tuples for options,
     separating the elements by spaces before passing the resulting
     value to Tcl/Tk.  (Contributed by Guilherme Polo; bpo-2906(52).)

   * The *note turtle: 101. module for turtle graphics was greatly
     enhanced by Gregor Lingl.  New features in the module include:

        * Better animation of turtle movement and rotation.

        * Control over turtle movement using the new ‘delay()’,
          ‘tracer()’, and ‘speed()’ methods.

        * The ability to set new shapes for the turtle, and to define a
          new coordinate system.

        * Turtles now have an ‘undo()’ method that can roll back
          actions.

        * Simple support for reacting to input events such as mouse and
          keyboard activity, making it possible to write simple games.

        * A ‘turtle.cfg’ file can be used to customize the starting
          appearance of the turtle’s screen.

        * The module’s docstrings can be replaced by new docstrings that
          have been translated into another language.

     (bpo-1513695(53))

   * An optional ‘timeout’ parameter was added to the *note
     urllib.urlopen: 293. function and the ‘urllib.ftpwrapper’ class
     constructor, as well as the ‘urllib2.urlopen’ function.  The
     parameter specifies a timeout measured in seconds.  For example:

          >>> u = urllib2.urlopen("http://slow.example.com",
                                  timeout=3)
          Traceback (most recent call last):
            ...
          urllib2.URLError: <urlopen error timed out>
          >>>

     (Added by Facundo Batista.)

   * The Unicode database provided by the *note unicodedata: 105. module
     has been updated to version 5.1.0.  (Updated by Martin von Löwis;
     bpo-3811(54).)

   * The *note warnings: 112. module’s ‘formatwarning()’ and
     ‘showwarning()’ gained an optional 'line' argument that can be used
     to supply the line of source code.  (Added as part of
     bpo-1631171(55), which re-implemented part of the ‘warnings’ module
     in C code.)

     A new function, ‘catch_warnings()’, is a context manager intended
     for testing purposes that lets you temporarily modify the warning
     filters and then restore their original values (bpo-3781(56)).

   * The XML-RPC *note SimpleXMLRPCServer: 12f. and ‘DocXMLRPCServer’
     classes can now be prevented from immediately opening and binding
     to their socket by passing ‘False’ as the 'bind_and_activate'
     constructor parameter.  This can be used to modify the instance’s
     ‘allow_reuse_address’ attribute before calling the ‘server_bind()’
     and ‘server_activate()’ methods to open the socket and begin
     listening for connections.  (Contributed by Peter Parente;
     bpo-1599845(57).)

     ‘SimpleXMLRPCServer’ also has a ‘_send_traceback_header’ attribute;
     if true, the exception and formatted traceback are returned as HTTP
     headers “X-Exception” and “X-Traceback”.  This feature is for
     debugging purposes only and should not be used on production
     servers because the tracebacks might reveal passwords or other
     sensitive information.  (Contributed by Alan McIntyre as part of
     his project for Google’s Summer of Code 2007.)

   * The *note xmlrpclib: 12e. module no longer automatically converts
     *note datetime.date: 1cd. and *note datetime.time: 1ce. to the
     *note xmlrpclib.DateTime: 1431. type; the conversion semantics were
     not necessarily correct for all applications.  Code using
     ‘xmlrpclib’ should convert ‘date’ and ‘time’ instances.
     (bpo-1330538(58)) The code can also handle dates before 1900
     (contributed by Ralf Schmitt; bpo-2014(59)) and 64-bit integers
     represented by using ‘<i8>’ in XML-RPC responses (contributed by
     Riku Lindblad; bpo-2985(60)).

   * The *note zipfile: 131. module’s ‘ZipFile’ class now has
     ‘extract()’ and ‘extractall()’ methods that will unpack a single
     file or all the files in the archive to the current directory, or
     to a specified directory:

          z = zipfile.ZipFile('python-251.zip')

          # Unpack a single file, writing it relative
          # to the /tmp directory.
          z.extract('Python/sysmodule.c', '/tmp')

          # Unpack all the files in the archive.
          z.extractall()

     (Contributed by Alan McIntyre; bpo-467924(61).)

     The *note open(): 51f, ‘read()’ and ‘extract()’ methods can now
     take either a filename or a ‘ZipInfo’ object.  This is useful when
     an archive accidentally contains a duplicated filename.
     (Contributed by Graham Horler; bpo-1775025(62).)

     Finally, *note zipfile: 131. now supports using Unicode filenames
     for archived files.  (Contributed by Alexey Borzenkov;
     bpo-1734346(63).)

* Menu:

* The ast module::
* The future_builtins module::
* The json module; JavaScript Object Notation: The json module JavaScript Object Notation.
* The plistlib module; A Property-List Parser: The plistlib module A Property-List Parser.
* ctypes Enhancements::
* Improved SSL Support::

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1736190

   (2) https://www.jcea.es/programacion/pybsddb.htm

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1817

   (4) https://bugs.python.org/issue?@action=redirect&bpo=600362

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1381

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1638033

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1158

   (8) https://speleotrove.com/decimal/decarith.html

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1221598

   (10) https://bugs.python.org/issue?@action=redirect&bpo=1739906

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1001604

   (12) https://bugs.python.org/issue?@action=redirect&bpo=2138

   (13) https://bugs.python.org/issue?@action=redirect&bpo=2819

   (14) https://bugs.python.org/issue?@action=redirect&bpo=711019

   (15) https://bugs.python.org/issue?@action=redirect&bpo=1640

   (16) https://bugs.python.org/issue?@action=redirect&bpo=1663329

   (17) https://bugs.python.org/issue?@action=redirect&bpo=1181

   (18) https://bugs.python.org/issue?@action=redirect&bpo=1273829

   (19) https://bugs.python.org/issue?@action=redirect&bpo=1115886

   (20) https://bugs.python.org/issue?@action=redirect&bpo=1339796

   (21) https://bugs.python.org/issue?@action=redirect&bpo=957650

   (22) https://bugs.python.org/issue?@action=redirect&bpo=1393667

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1106316

   (24) https://bugs.python.org/issue?@action=redirect&bpo=2439

   (25) https://bugs.python.org/issue?@action=redirect&bpo=1137

   (26) https://bugs.python.org/issue?@action=redirect&bpo=1727780

   (27) https://bugs.python.org/issue?@action=redirect&bpo=1681432

   (28) https://bugs.python.org/issue?@action=redirect&bpo=846388

   (29) https://bugs.python.org/issue?@action=redirect&bpo=3487

   (30) https://bugs.python.org/issue?@action=redirect&bpo=2250

   (31) https://bugs.python.org/issue?@action=redirect&bpo=1861

   (32) https://bugs.python.org/issue?@action=redirect&bpo=1657

   (33) https://bugs.python.org/issue?@action=redirect&bpo=2663

   (34) https://bugs.python.org/issue?@action=redirect&bpo=1583

   (35) https://bugs.python.org/issue?@action=redirect&bpo=2240

   (36) https://datatracker.ietf.org/doc/html/rfc2033.html

   (37) https://bugs.python.org/issue?@action=redirect&bpo=957003

   (38) https://datatracker.ietf.org/doc/html/rfc3207.html

   (39) https://bugs.python.org/issue?@action=redirect&bpo=829951

   (40) https://bugs.python.org/issue?@action=redirect&bpo=1646

   (41) https://bugs.python.org/issue?@action=redirect&bpo=742598

   (42) https://bugs.python.org/issue?@action=redirect&bpo=1193577

   (43) https://bugs.python.org/issue?@action=redirect&bpo=1534

   (44) https://bugs.python.org/issue?@action=redirect&bpo=2898

   (45) https://bugs.python.org/issue?@action=redirect&bpo=1648

   (46) https://bugs.python.org/issue?@action=redirect&bpo=1537850

   (47) https://bugs.python.org/issue?@action=redirect&bpo=2021

   (48) https://bugs.python.org/issue?@action=redirect&bpo=3781

   (49) https://bugs.python.org/issue?@action=redirect&bpo=1581073

   (50) https://bugs.python.org/issue?@action=redirect&bpo=2871

   (51) https://bugs.python.org/issue?@action=redirect&bpo=1533909

   (52) https://bugs.python.org/issue?@action=redirect&bpo=2906

   (53) https://bugs.python.org/issue?@action=redirect&bpo=1513695

   (54) https://bugs.python.org/issue?@action=redirect&bpo=3811

   (55) https://bugs.python.org/issue?@action=redirect&bpo=1631171

   (56) https://bugs.python.org/issue?@action=redirect&bpo=3781

   (57) https://bugs.python.org/issue?@action=redirect&bpo=1599845

   (58) https://bugs.python.org/issue?@action=redirect&bpo=1330538

   (59) https://bugs.python.org/issue?@action=redirect&bpo=2014

   (60) https://bugs.python.org/issue?@action=redirect&bpo=2985

   (61) https://bugs.python.org/issue?@action=redirect&bpo=467924

   (62) https://bugs.python.org/issue?@action=redirect&bpo=1775025

   (63) https://bugs.python.org/issue?@action=redirect&bpo=1734346


File: python.info,  Node: The ast module,  Next: The future_builtins module,  Up: New and Improved Modules<2>

1.16.18.1 The ‘ast’ module
..........................

The *note ast: 8. module provides an Abstract Syntax Tree representation
of Python code, and Armin Ronacher contributed a set of helper functions
that perform a variety of common tasks.  These will be useful for HTML
templating packages, code analyzers, and similar tools that process
Python code.

The ‘parse()’ function takes an expression and returns an AST. The
‘dump()’ function outputs a representation of a tree, suitable for
debugging:

     import ast

     t = ast.parse("""
     d = {}
     for i in 'abcdefghijklm':
         d[i + i] = ord(i) - ord('a') + 1
     print d
     """)
     print ast.dump(t)

This outputs a deeply nested tree:

     Module(body=[
       Assign(targets=[
         Name(id='d', ctx=Store())
        ], value=Dict(keys=[], values=[]))
       For(target=Name(id='i', ctx=Store()),
           iter=Str(s='abcdefghijklm'), body=[
         Assign(targets=[
           Subscript(value=
             Name(id='d', ctx=Load()),
               slice=
               Index(value=
                 BinOp(left=Name(id='i', ctx=Load()), op=Add(),
                  right=Name(id='i', ctx=Load()))), ctx=Store())
          ], value=
          BinOp(left=
           BinOp(left=
            Call(func=
             Name(id='ord', ctx=Load()), args=[
               Name(id='i', ctx=Load())
              ], keywords=[], starargs=None, kwargs=None),
            op=Sub(), right=Call(func=
             Name(id='ord', ctx=Load()), args=[
               Str(s='a')
              ], keywords=[], starargs=None, kwargs=None)),
            op=Add(), right=Num(n=1)))
         ], orelse=[])
        Print(dest=None, values=[
          Name(id='d', ctx=Load())
        ], nl=True)
      ])

The ‘literal_eval()’ method takes a string or an AST representing a
literal expression, parses and evaluates it, and returns the resulting
value.  A literal expression is a Python expression containing only
strings, numbers, dictionaries, etc.  but no statements or function
calls.  If you need to evaluate an expression but cannot accept the
security risk of using an *note eval(): 180. call, ‘literal_eval()’ will
handle it safely:

     >>> literal = '("a", "b", {2:4, 3:8, 1:2})'
     >>> print ast.literal_eval(literal)
     ('a', 'b', {1: 2, 2: 4, 3: 8})
     >>> print ast.literal_eval('"a" + "b"')
     Traceback (most recent call last):
       ...
     ValueError: malformed string

The module also includes ‘NodeVisitor’ and ‘NodeTransformer’ classes for
traversing and modifying an AST, and functions for common
transformations such as changing line numbers.


File: python.info,  Node: The future_builtins module,  Next: The json module JavaScript Object Notation,  Prev: The ast module,  Up: New and Improved Modules<2>

1.16.18.2 The ‘future_builtins’ module
......................................

Python 3.0 makes many changes to the repertoire of built-in functions,
and most of the changes can’t be introduced in the Python 2.x series
because they would break compatibility.  The ‘future_builtins’ module
provides versions of these built-in functions that can be imported when
writing 3.0-compatible code.

The functions in this module currently include:

   * ‘ascii(obj)’: equivalent to *note repr(): 803.  In Python 3.0,
     ‘repr()’ will return a Unicode string, while *note ascii(): 1434.
     will return a pure ASCII bytestring.

   * ‘filter(predicate, iterable)’, ‘map(func, iterable1, ...)’: the 3.0
     versions return iterators, unlike the 2.x builtins which return
     lists.

   * ‘hex(value)’, ‘oct(value)’: instead of calling the ‘__hex__()’ or
     ‘__oct__()’ methods, these versions will call the ‘__index__()’
     method and convert the result to hexadecimal or octal.  *note
     oct(): 1316. will use the new ‘0o’ notation for its result.


File: python.info,  Node: The json module JavaScript Object Notation,  Next: The plistlib module A Property-List Parser,  Prev: The future_builtins module,  Up: New and Improved Modules<2>

1.16.18.3 The ‘json’ module: JavaScript Object Notation
.......................................................

The new *note json: 82. module supports the encoding and decoding of
Python types in JSON (Javascript Object Notation).  JSON is a
lightweight interchange format often used in web applications.  For more
information about JSON, see ‘http://www.json.org’.

*note json: 82. comes with support for decoding and encoding most
built-in Python types.  The following example encodes and decodes a
dictionary:

     >>> import json
     >>> data = {"spam": "foo", "parrot": 42}
     >>> in_json = json.dumps(data) # Encode the data
     >>> in_json
     '{"parrot": 42, "spam": "foo"}'
     >>> json.loads(in_json) # Decode into a Python object
     {"spam": "foo", "parrot": 42}

It’s also possible to write your own decoders and encoders to support
more types.  Pretty-printing of the JSON strings is also supported.

*note json: 82. (originally called simplejson) was written by Bob
Ippolito.


File: python.info,  Node: The plistlib module A Property-List Parser,  Next: ctypes Enhancements,  Prev: The json module JavaScript Object Notation,  Up: New and Improved Modules<2>

1.16.18.4 The ‘plistlib’ module: A Property-List Parser
.......................................................

The ‘.plist’ format is commonly used on Mac OS X to store basic data
types (numbers, strings, lists, and dictionaries) by serializing them
into an XML-based format.  It resembles the XML-RPC serialization of
data types.

Despite being primarily used on Mac OS X, the format has nothing
Mac-specific about it and the Python implementation works on any
platform that Python supports, so the *note plistlib: ab. module has
been promoted to the standard library.

Using the module is simple:

     import sys
     import plistlib
     import datetime as dt

     # Create data structure
     data_struct = dict(lastAccessed=dt.datetime.now(),
                        version=1,
                        categories=('Personal','Shared','Private'))

     # Create string containing XML.
     plist_str = plistlib.writePlistToString(data_struct)
     new_struct = plistlib.readPlistFromString(plist_str)
     print data_struct
     print new_struct

     # Write data structure to a file and read it back.
     plistlib.writePlist(data_struct, '/tmp/customizations.plist')
     new_struct = plistlib.readPlist('/tmp/customizations.plist')

     # read/writePlist accepts file-like objects as well as paths.
     plistlib.writePlist(data_struct, sys.stdout)


File: python.info,  Node: ctypes Enhancements,  Next: Improved SSL Support,  Prev: The plistlib module A Property-List Parser,  Up: New and Improved Modules<2>

1.16.18.5 ctypes Enhancements
.............................

Thomas Heller continued to maintain and enhance the *note ctypes: 2a.
module.

*note ctypes: 2a. now supports a ‘c_bool’ datatype that represents the
C99 ‘bool’ type.  (Contributed by David Remahl; bpo-1649190(1).)

The *note ctypes: 2a. string, buffer and array types have improved
support for extended slicing syntax, where various combinations of
‘(start, stop, step)’ are supplied.  (Implemented by Thomas Wouters.)

All *note ctypes: 2a. data types now support ‘from_buffer()’ and
‘from_buffer_copy()’ methods that create a ctypes instance based on a
provided buffer object.  ‘from_buffer_copy()’ copies the contents of the
object, while ‘from_buffer()’ will share the same memory area.

A new calling convention tells *note ctypes: 2a. to clear the ‘errno’ or
Win32 LastError variables at the outset of each wrapped call.
(Implemented by Thomas Heller; bpo-1798(2).)

You can now retrieve the Unix ‘errno’ variable after a function call.
When creating a wrapped function, you can supply ‘use_errno=True’ as a
keyword parameter to the ‘DLL()’ function and then call the module-level
methods ‘set_errno()’ and ‘get_errno()’ to set and retrieve the error
value.

The Win32 LastError variable is similarly supported by the ‘DLL()’,
‘OleDLL()’, and ‘WinDLL()’ functions.  You supply ‘use_last_error=True’
as a keyword parameter and then call the module-level methods
‘set_last_error()’ and ‘get_last_error()’.

The ‘byref()’ function, used to retrieve a pointer to a ctypes instance,
now has an optional 'offset' parameter that is a byte count that will be
added to the returned pointer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1649190

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1798


File: python.info,  Node: Improved SSL Support,  Prev: ctypes Enhancements,  Up: New and Improved Modules<2>

1.16.18.6 Improved SSL Support
..............................

Bill Janssen made extensive improvements to Python 2.6’s support for the
Secure Sockets Layer by adding a new module, *note ssl: d0, that’s built
atop the OpenSSL(1) library.  This new module provides more control over
the protocol negotiated, the X.509 certificates used, and has better
support for writing SSL servers (as opposed to clients) in Python.  The
existing SSL support in the *note socket: cc. module hasn’t been removed
and continues to work, though it will be removed in Python 3.0.

To use the new module, you must first create a TCP connection in the
usual way and then pass it to the ‘ssl.wrap_socket()’ function.  It’s
possible to specify whether a certificate is required, and to obtain
certificate info by calling the ‘getpeercert()’ method.

See also
........

The documentation for the *note ssl: d0. module.

   ---------- Footnotes ----------

   (1) https://www.openssl.org/


File: python.info,  Node: Deprecations and Removals,  Next: Build and C API Changes<9>,  Prev: New and Improved Modules<2>,  Up: What’s New in Python 2 6

1.16.19 Deprecations and Removals
---------------------------------

   * String exceptions have been removed.  Attempting to use them raises
     a *note TypeError: 2c3.

   * Changes to the *note Exception: 9e5. interface as dictated by PEP
     352(1) continue to be made.  For 2.6, the ‘message’ attribute is
     being deprecated in favor of the *note args: 56f. attribute.

   * (3.0-warning mode) Python 3.0 will feature a reorganized standard
     library that will drop many outdated modules and rename others.
     Python 2.6 running in 3.0-warning mode will warn about these
     modules when they are imported.

     The list of deprecated modules is: ‘audiodev’, ‘bgenlocations’,
     ‘buildtools’, ‘bundlebuilder’, ‘Canvas’, ‘compiler’, ‘dircache’,
     ‘dl’, ‘fpformat’, ‘gensuitemodule’, ‘ihooks’, ‘imageop’, ‘imgfile’,
     ‘linuxaudiodev’, ‘mhlib’, ‘mimetools’, ‘multifile’, ‘new’, ‘pure’,
     ‘statvfs’, ‘sunaudiodev’, ‘test.testall’, and ‘toaiff’.

   * The ‘gopherlib’ module has been removed.

   * The ‘MimeWriter’ module and ‘mimify’ module have been deprecated;
     use the *note email: 3b. package instead.

   * The ‘md5’ module has been deprecated; use the *note hashlib: 68.
     module instead.

   * The ‘posixfile’ module has been deprecated; *note fcntl.lockf():
     143a. provides better locking.

   * The ‘popen2’ module has been deprecated; use the *note subprocess:
     d6. module.

   * The ‘rgbimg’ module has been removed.

   * The ‘sets’ module has been deprecated; it’s better to use the
     built-in *note set: 5dc. and *note frozenset: 5dd. types.

   * The ‘sha’ module has been deprecated; use the *note hashlib: 68.
     module instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0352/


File: python.info,  Node: Build and C API Changes<9>,  Next: Porting to Python 2 6,  Prev: Deprecations and Removals,  Up: What’s New in Python 2 6

1.16.20 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * Python now must be compiled with C89 compilers (after 19 years!).
     This means that the Python source tree has dropped its own
     implementations of ‘memmove()’ and ‘strerror()’, which are in the
     C89 standard library.

   * Python 2.6 can be built with Microsoft Visual Studio 2008 (version
     9.0), and this is the new default compiler.  See the ‘PCbuild’
     directory for the build files.  (Implemented by Christian Heimes.)

   * On Mac OS X, Python 2.6 can be compiled as a 4-way universal build.
     The ‘configure’ script can take a
     ‘--with-universal-archs=[32-bit|64-bit|all]’ switch, controlling
     whether the binaries are built for 32-bit architectures (x86,
     PowerPC), 64-bit (x86-64 and PPC-64), or both.  (Contributed by
     Ronald Oussoren.)

   * A new function added in Python 2.6.6, ‘PySys_SetArgvEx()’, sets the
     value of ‘sys.argv’ and can optionally update ‘sys.path’ to include
     the directory containing the script named by ‘sys.argv[0]’
     depending on the value of an 'updatepath' parameter.

     This function was added to close a security hole for applications
     that embed Python.  The old function, ‘PySys_SetArgv()’, would
     always update ‘sys.path’, and sometimes it would add the current
     directory.  This meant that, if you ran an application embedding
     Python in a directory controlled by someone else, attackers could
     put a Trojan-horse module in the directory (say, a file named
     ‘os.py’) that your application would then import and run.

     If you maintain a C/C++ application that embeds Python, check
     whether you’re calling ‘PySys_SetArgv()’ and carefully consider
     whether the application should be using ‘PySys_SetArgvEx()’ with
     'updatepath' set to false.  Note that using this function will
     break compatibility with Python versions 2.6.5 and earlier; if you
     have to continue working with earlier versions, you can leave the
     call to ‘PySys_SetArgv()’ alone and call
     ‘PyRun_SimpleString("sys.path.pop(0)\n")’ afterwards to discard the
     first ‘sys.path’ component.

     Security issue reported as CVE 2008-5983(1); discussed in
     gh-50003(2), and fixed by Antoine Pitrou.

   * The BerkeleyDB module now has a C API object, available as
     ‘bsddb.db.api’.  This object can be used by other C extensions that
     wish to use the ‘bsddb’ module for their own purposes.
     (Contributed by Duncan Grisby.)

   * The new buffer interface, previously described in *note the PEP
     3118 section: 1401, adds *note PyObject_GetBuffer(): 39c. and *note
     PyBuffer_Release(): 39d, as well as a few other functions.

   * Python’s use of the C stdio library is now thread-safe, or at least
     as thread-safe as the underlying library is.  A long-standing
     potential bug occurred if one thread closed a file object while
     another thread was reading from or writing to the object.  In 2.6
     file objects have a reference count, manipulated by the
     ‘PyFile_IncUseCount()’ and ‘PyFile_DecUseCount()’ functions.  File
     objects can’t be closed unless the reference count is zero.
     ‘PyFile_IncUseCount()’ should be called while the GIL is still
     held, before carrying out an I/O operation using the ‘FILE *’
     pointer, and ‘PyFile_DecUseCount()’ should be called immediately
     after the GIL is re-acquired.  (Contributed by Antoine Pitrou and
     Gregory P. Smith.)

   * Importing modules simultaneously in two different threads no longer
     deadlocks; it will now raise an *note ImportError: 41c.  A new API
     function, *note PyImport_ImportModuleNoBlock(): 3c0, will look for
     a module in ‘sys.modules’ first, then try to import it after
     acquiring an import lock.  If the import lock is held by another
     thread, an ‘ImportError’ is raised.  (Contributed by Christian
     Heimes.)

   * Several functions return information about the platform’s
     floating-point support.  *note PyFloat_GetMax(): 143c. returns the
     maximum representable floating-point value, and *note
     PyFloat_GetMin(): 143d. returns the minimum positive value.  *note
     PyFloat_GetInfo(): 143e. returns an object containing more
     information from the ‘float.h’ file, such as ‘"mant_dig"’ (number
     of digits in the mantissa), ‘"epsilon"’ (smallest difference
     between 1.0 and the next largest value representable), and several
     others.  (Contributed by Christian Heimes; bpo-1534(3).)

   * C functions and methods that use *note PyComplex_AsCComplex():
     143f. will now accept arguments that have a ‘__complex__()’ method.
     In particular, the functions in the *note cmath: 18. module will
     now accept objects with this method.  This is a backport of a
     Python 3.0 change.  (Contributed by Mark Dickinson;
     bpo-1675423(4).)

   * Python’s C API now includes two functions for case-insensitive
     string comparisons, ‘PyOS_stricmp(char*, char*)’ and
     ‘PyOS_strnicmp(char*, char*, Py_ssize_t)’.  (Contributed by
     Christian Heimes; bpo-1635(5).)

   * Many C extensions define their own little macro for adding integers
     and strings to the module’s dictionary in the ‘init*’ function.
     Python 2.6 finally defines standard macros for adding values to a
     module, *note PyModule_AddStringMacro: 1440. and *note
     PyModule_AddIntMacro(): 1441.  (Contributed by Christian Heimes.)

   * Some macros were renamed in both 3.0 and 2.6 to make it clearer
     that they are macros, not functions.  ‘Py_Size()’ became *note
     Py_SIZE(): 785, ‘Py_Type()’ became *note Py_TYPE(): 783, and
     ‘Py_Refcnt()’ became *note Py_REFCNT(): 8b1.  The mixed-case macros
     are still available in Python 2.6 for backward compatibility.
     (bpo-1629(6))

   * Distutils now places C extensions it builds in a different
     directory when running on a debug version of Python.  (Contributed
     by Collin Winter; bpo-1530959(7).)

   * Several basic data types, such as integers and strings, maintain
     internal free lists of objects that can be re-used.  The data
     structures for these free lists now follow a naming convention: the
     variable is always named ‘free_list’, the counter is always named
     ‘numfree’, and a macro ‘Py<typename>_MAXFREELIST’ is always
     defined.

   * A new Makefile target, “make patchcheck”, prepares the Python
     source tree for making a patch: it fixes trailing whitespace in all
     modified ‘.py’ files, checks whether the documentation has been
     changed, and reports whether the ‘Misc/ACKS’ and ‘Misc/NEWS’ files
     have been updated.  (Contributed by Brett Cannon.)

     Another new target, “make profile-opt”, compiles a Python binary
     using GCC’s profile-guided optimization.  It compiles Python with
     profiling enabled, runs the test suite to obtain a set of profiling
     results, and then compiles using these results for optimization.
     (Contributed by Gregory P. Smith.)

* Menu:

* Port-Specific Changes; Windows: Port-Specific Changes Windows<2>.
* Port-Specific Changes; Mac OS X: Port-Specific Changes Mac OS X<2>.
* Port-Specific Changes; IRIX: Port-Specific Changes IRIX.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2008-5983

   (2) https://github.com/python/cpython/issues/50003

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1534

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1675423

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1635

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1629

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1530959


File: python.info,  Node: Port-Specific Changes Windows<2>,  Next: Port-Specific Changes Mac OS X<2>,  Up: Build and C API Changes<9>

1.16.20.1 Port-Specific Changes: Windows
........................................

   * The support for Windows 95, 98, ME and NT4 has been dropped.
     Python 2.6 requires at least Windows 2000 SP4.

   * The new default compiler on Windows is Visual Studio 2008 (version
     9.0).  The build directories for Visual Studio 2003 (version 7.1)
     and 2005 (version 8.0) were moved into the PC/ directory.  The new
     ‘PCbuild’ directory supports cross compilation for X64, debug
     builds and Profile Guided Optimization (PGO). PGO builds are
     roughly 10% faster than normal builds.  (Contributed by Christian
     Heimes with help from Amaury Forgeot d’Arc and Martin von Löwis.)

   * The *note msvcrt: 93. module now supports both the normal and wide
     char variants of the console I/O API. The *note getwch(): 1443.
     function reads a keypress and returns a Unicode value, as does the
     *note getwche(): 1444. function.  The *note putwch(): 1445.
     function takes a Unicode character and writes it to the console.
     (Contributed by Christian Heimes.)

   * *note os.path.expandvars(): 1427. will now expand environment
     variables in the form “%var%”, and “~user” will be expanded into
     the user’s home directory path.  (Contributed by Josiah Carlson;
     bpo-957650(1).)

   * The *note socket: cc. module’s socket objects now have an *note
     ioctl(): cf9. method that provides a limited interface to the
     ‘WSAIoctl()’ system interface.

   * The *note _winreg: 116. module now has a function, *note
     ExpandEnvironmentStrings(): 1446, that expands environment variable
     references such as ‘%NAME%’ in an input string.  The handle objects
     provided by this module now support the context protocol, so they
     can be used in *note with: 5d5. statements.  (Contributed by
     Christian Heimes.)

     *note _winreg: 116. also has better support for x64 systems,
     exposing the *note DisableReflectionKey(): 13b1, *note
     EnableReflectionKey(): 13b2, and *note QueryReflectionKey(): 13b3.
     functions, which enable and disable registry reflection for 32-bit
     processes running on 64-bit systems.  (bpo-1753245(2))

   * The ‘msilib’ module’s ‘Record’ object gained ‘GetInteger()’ and
     ‘GetString()’ methods that return field values as an integer or a
     string.  (Contributed by Floris Bruynooghe; bpo-2125(3).)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=957650

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1753245

   (3) https://bugs.python.org/issue?@action=redirect&bpo=2125


File: python.info,  Node: Port-Specific Changes Mac OS X<2>,  Next: Port-Specific Changes IRIX,  Prev: Port-Specific Changes Windows<2>,  Up: Build and C API Changes<9>

1.16.20.2 Port-Specific Changes: Mac OS X
.........................................

   * When compiling a framework build of Python, you can now specify the
     framework name to be used by providing the ‘--with-framework-name=’
     option to the ‘configure’ script.

   * The ‘macfs’ module has been removed.  This in turn required the
     ‘macostools.touched()’ function to be removed because it depended
     on the ‘macfs’ module.  (bpo-1490190(1))

   * Many other Mac OS modules have been deprecated and will be removed
     in Python 3.0: ‘_builtinSuites’, ‘aepack’, ‘aetools’, ‘aetypes’,
     ‘applesingle’, ‘appletrawmain’, ‘appletrunner’, ‘argvemulator’,
     ‘Audio_mac’, ‘autoGIL’, ‘Carbon’, ‘cfmfile’, ‘CodeWarrior’,
     ‘ColorPicker’, ‘EasyDialogs’, ‘Explorer’, ‘Finder’, ‘FrameWork’,
     ‘findertools’, ‘ic’, ‘icglue’, ‘icopen’, ‘macerrors’, ‘MacOS’,
     ‘macfs’, ‘macostools’, ‘macresource’, ‘MiniAEFrame’, ‘Nav’,
     ‘Netscape’, ‘OSATerminology’, ‘pimp’, ‘PixMapWrapper’, ‘StdSuites’,
     ‘SystemEvents’, ‘Terminal’, and ‘terminalcommand’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1490190


File: python.info,  Node: Port-Specific Changes IRIX,  Prev: Port-Specific Changes Mac OS X<2>,  Up: Build and C API Changes<9>

1.16.20.3 Port-Specific Changes: IRIX
.....................................

A number of old IRIX-specific modules were deprecated and will be
removed in Python 3.0: ‘al’ and ‘AL’, ‘cd’, ‘cddb’, ‘cdplayer’, ‘CL’ and
‘cl’, ‘DEVICE’, ‘ERRNO’, ‘FILE’, ‘FL’ and ‘fl’, ‘flp’, ‘fm’, ‘GET’,
‘GLWS’, ‘GL’ and ‘gl’, ‘IN’, ‘IOCTL’, ‘jpeg’, ‘panelparser’, ‘readcd’,
‘SV’ and ‘sv’, ‘torgb’, ‘videoreader’, and ‘WAIT’.


File: python.info,  Node: Porting to Python 2 6,  Next: Acknowledgements<2>,  Prev: Build and C API Changes<9>,  Up: What’s New in Python 2 6

1.16.21 Porting to Python 2.6
-----------------------------

This section lists previously described changes and other bugfixes that
may require changes to your code:

   * Classes that aren’t supposed to be hashable should set ‘__hash__ =
     None’ in their definitions to indicate the fact.

   * String exceptions have been removed.  Attempting to use them raises
     a *note TypeError: 2c3.

   * The ‘__init__()’ method of *note collections.deque: 5df. now clears
     any existing contents of the deque before adding elements from the
     iterable.  This change makes the behavior match ‘list.__init__()’.

   * *note object.__init__(): 6b3. previously accepted arbitrary
     arguments and keyword arguments, ignoring them.  In Python 2.6,
     this is no longer allowed and will result in a *note TypeError:
     2c3.  This will affect ‘__init__()’ methods that end up calling the
     corresponding method on *note object: a9b. (perhaps through using
     *note super(): 4de.).  See bpo-1683368(1) for discussion.

   * The ‘Decimal’ constructor now accepts leading and trailing
     whitespace when passed a string.  Previously it would raise an
     ‘InvalidOperation’ exception.  On the other hand, the
     ‘create_decimal()’ method of ‘Context’ objects now explicitly
     disallows extra whitespace, raising a ‘ConversionSyntax’ exception.

   * Due to an implementation accident, if you passed a file path to the
     built-in *note __import__(): 8dd. function, it would actually
     import the specified file.  This was never intended to work,
     however, and the implementation now explicitly checks for this case
     and raises an *note ImportError: 41c.

   * C API: the *note PyImport_Import(): 144a. and *note
     PyImport_ImportModule(): 3c1. functions now default to absolute
     imports, not relative imports.  This will affect C extensions that
     import other modules.

   * C API: extension data types that shouldn’t be hashable should
     define their ‘tp_hash’ slot to *note PyObject_HashNotImplemented():
     1413.

   * The *note socket: cc. module exception *note socket.error: 1093.
     now inherits from *note IOError: 1090.  Previously it wasn’t a
     subclass of ‘StandardError’ but now it is, through ‘IOError’.
     (Implemented by Gregory P. Smith; bpo-1706815(2).)

   * The *note xmlrpclib: 12e. module no longer automatically converts
     *note datetime.date: 1cd. and *note datetime.time: 1ce. to the
     *note xmlrpclib.DateTime: 1431. type; the conversion semantics were
     not necessarily correct for all applications.  Code using
     ‘xmlrpclib’ should convert ‘date’ and ‘time’ instances.
     (bpo-1330538(3))

   * (3.0-warning mode) The *note Exception: 9e5. class now warns when
     accessed using slicing or index access; having ‘Exception’ behave
     like a tuple is being phased out.

   * (3.0-warning mode) inequality comparisons between two dictionaries
     or two objects that don’t implement comparison methods are reported
     as warnings.  ‘dict1 == dict2’ still works, but ‘dict1 < dict2’ is
     being phased out.

     Comparisons between cells, which are an implementation detail of
     Python’s scoping rules, also cause warnings because such
     comparisons are forbidden entirely in 3.0.

For applications that embed Python:

   * The ‘PySys_SetArgvEx()’ function was added in Python 2.6.6, letting
     applications close a security hole when the existing
     ‘PySys_SetArgv()’ function was used.  Check whether you’re calling
     ‘PySys_SetArgv()’ and carefully consider whether the application
     should be using ‘PySys_SetArgvEx()’ with 'updatepath' set to false.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1683368

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1706815

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1330538


File: python.info,  Node: Acknowledgements<2>,  Prev: Porting to Python 2 6,  Up: What’s New in Python 2 6

1.16.22 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Georg Brandl, Steve Brown, Nick Coghlan, Ralph Corderoy, Jim
Jewett, Kent Johnson, Chris Lambacher, Martin Michlmayr, Antoine Pitrou,
Brian Warner.


File: python.info,  Node: What’s New in Python 2 5,  Next: What’s New in Python 2 4,  Prev: What’s New in Python 2 6,  Up: What’s New in Python

1.17 What’s New in Python 2.5
=============================


Author: A.M. Kuchling

This article explains the new features in Python 2.5.  The final release
of Python 2.5 is scheduled for August 2006; PEP 356(1) describes the
planned release schedule.  Python 2.5 was released on September 19,
2006.

The changes in Python 2.5 are an interesting mix of language and library
improvements.  The library enhancements will be more important to
Python’s user community, I think, because several widely useful packages
were added.  New modules include ElementTree for XML processing
(‘xml.etree’), the SQLite database module (‘sqlite’), and the *note
ctypes: 2a. module for calling C functions.

The language changes are of middling significance.  Some pleasant new
features were added, but most of them aren’t features that you’ll use
every day.  Conditional expressions were finally added to the language
using a novel syntax; see section *note PEP 308; Conditional
Expressions: 1450.  The new ‘*note with: 5d5.’ statement will make
writing cleanup code easier (section *note PEP 343; The ‘with’
statement: 1451.).  Values can now be passed into generators (section
*note PEP 342; New Generator Features: 1452.).  Imports are now visible
as either absolute or relative (section *note PEP 328; Absolute and
Relative Imports: 1453.).  Some corner cases of exception handling are
handled better (section *note PEP 341; Unified try/except/finally:
1454.).  All these improvements are worthwhile, but they’re improvements
to one specific language feature or another; none of them are broad
modifications to Python’s semantics.

As well as the language and library additions, other improvements and
bugfixes were made throughout the source tree.  A search through the SVN
change logs finds there were 353 patches applied and 458 bugs fixed
between Python 2.4 and 2.5.  (Both figures are likely to be
underestimates.)

This article doesn’t try to be a complete specification of the new
features; instead changes are briefly introduced using helpful examples.
For full details, you should always refer to the documentation for
Python 2.5 at ‘https://docs.python.org’.  If you want to understand the
complete implementation and design rationale, refer to the PEP for a
particular new feature.

Comments, suggestions, and error reports for this document are welcome;
please e-mail them to the author or open a bug in the Python bug
tracker.

* Menu:

* PEP 308; Conditional Expressions: PEP 308 Conditional Expressions.
* PEP 309; Partial Function Application: PEP 309 Partial Function Application.
* PEP 314; Metadata for Python Software Packages v1.1: PEP 314 Metadata for Python Software Packages v1 1.
* PEP 328; Absolute and Relative Imports: PEP 328 Absolute and Relative Imports.
* PEP 338; Executing Modules as Scripts: PEP 338 Executing Modules as Scripts.
* PEP 341; Unified try/except/finally: PEP 341 Unified try/except/finally.
* PEP 342; New Generator Features: PEP 342 New Generator Features.
* PEP 343; The ‘with’ statement: PEP 343 The ‘with’ statement<2>.
* PEP 352; Exceptions as New-Style Classes: PEP 352 Exceptions as New-Style Classes.
* PEP 353; Using ssize_t as the index type: PEP 353 Using ssize_t as the index type.
* PEP 357; The ‘__index__’ method: PEP 357 The ‘__index__’ method.
* Other Language Changes: Other Language Changes<16>.
* New, Improved, and Removed Modules: New Improved and Removed Modules.
* Build and C API Changes: Build and C API Changes<10>.
* Porting to Python 2.5: Porting to Python 2 5.
* Acknowledgements: Acknowledgements<3>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0356/


File: python.info,  Node: PEP 308 Conditional Expressions,  Next: PEP 309 Partial Function Application,  Up: What’s New in Python 2 5

1.17.1 PEP 308: Conditional Expressions
---------------------------------------

For a long time, people have been requesting a way to write conditional
expressions, which are expressions that return value A or value B
depending on whether a Boolean value is true or false.  A conditional
expression lets you write a single assignment statement that has the
same effect as the following:

     if condition:
         x = true_value
     else:
         x = false_value

There have been endless tedious discussions of syntax on both python-dev
and comp.lang.python.  A vote was even held that found the majority of
voters wanted conditional expressions in some form, but there was no
syntax that was preferred by a clear majority.  Candidates included C’s
‘cond ? true_v : false_v’, ‘if cond then true_v else false_v’, and 16
other variations.

Guido van Rossum eventually chose a surprising syntax:

     x = true_value if condition else false_value

Evaluation is still lazy as in existing Boolean expressions, so the
order of evaluation jumps around a bit.  The 'condition' expression in
the middle is evaluated first, and the 'true_value' expression is
evaluated only if the condition was true.  Similarly, the 'false_value'
expression is only evaluated when the condition is false.

This syntax may seem strange and backwards; why does the condition go in
the 'middle' of the expression, and not in the front as in C’s ‘c ? x :
y’?  The decision was checked by applying the new syntax to the modules
in the standard library and seeing how the resulting code read.  In many
cases where a conditional expression is used, one value seems to be the
‘common case’ and one value is an ‘exceptional case’, used only on rarer
occasions when the condition isn’t met.  The conditional syntax makes
this pattern a bit more obvious:

     contents = ((doc + '\n') if doc else '')

I read the above statement as meaning “here 'contents' is usually
assigned a value of ‘doc+'\n'’; sometimes 'doc' is empty, in which
special case an empty string is returned.” I doubt I will use
conditional expressions very often where there isn’t a clear common and
uncommon case.

There was some discussion of whether the language should require
surrounding conditional expressions with parentheses.  The decision was
made to 'not' require parentheses in the Python language’s grammar, but
as a matter of style I think you should always use them.  Consider these
two statements:

     # First version -- no parens
     level = 1 if logging else 0

     # Second version -- with parens
     level = (1 if logging else 0)

In the first version, I think a reader’s eye might group the statement
into ‘level = 1’, ‘if logging’, ‘else 0’, and think that the condition
decides whether the assignment to 'level' is performed.  The second
version reads better, in my opinion, because it makes it clear that the
assignment is always performed and the choice is being made between two
values.

Another reason for including the brackets: a few odd combinations of
list comprehensions and lambdas could look like incorrect conditional
expressions.  See PEP 308(1) for some examples.  If you put parentheses
around your conditional expressions, you won’t run into this case.

See also
........

PEP 308(2) - Conditional Expressions

     PEP written by Guido van Rossum and Raymond D. Hettinger;
     implemented by Thomas Wouters.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0308/

   (2) https://peps.python.org/pep-0308/


File: python.info,  Node: PEP 309 Partial Function Application,  Next: PEP 314 Metadata for Python Software Packages v1 1,  Prev: PEP 308 Conditional Expressions,  Up: What’s New in Python 2 5

1.17.2 PEP 309: Partial Function Application
--------------------------------------------

The *note functools: 5f. module is intended to contain tools for
functional-style programming.

One useful tool in this module is the ‘partial()’ function.  For
programs written in a functional style, you’ll sometimes want to
construct variants of existing functions that have some of the
parameters filled in.  Consider a Python function ‘f(a, b, c)’; you
could create a new function ‘g(b, c)’ that was equivalent to ‘f(1, b,
c)’.  This is called “partial function application”.

‘partial()’ takes the arguments ‘(function, arg1, arg2, ...
kwarg1=value1, kwarg2=value2)’.  The resulting object is callable, so
you can just call it to invoke 'function' with the filled-in arguments.

Here’s a small but realistic example:

     import functools

     def log (message, subsystem):
         "Write the contents of 'message' to the specified subsystem."
         print '%s: %s' % (subsystem, message)
         ...

     server_log = functools.partial(log, subsystem='server')
     server_log('Unable to open socket')

Here’s another example, from a program that uses PyGTK. Here a
context-sensitive pop-up menu is being constructed dynamically.  The
callback provided for the menu option is a partially applied version of
the ‘open_item()’ method, where the first argument has been provided.

     ...
     class Application:
         def open_item(self, path):
            ...
         def init (self):
             open_func = functools.partial(self.open_item, item_path)
             popup_menu.append( ("Open", open_func, 1) )

Another function in the *note functools: 5f. module is the
‘update_wrapper(wrapper, wrapped)’ function that helps you write
well-behaved decorators.  ‘update_wrapper()’ copies the name, module,
and docstring attribute to a wrapper function so that tracebacks inside
the wrapped function are easier to understand.  For example, you might
write:

     def my_decorator(f):
         def wrapper(*args, **kwds):
             print 'Calling decorated function'
             return f(*args, **kwds)
         functools.update_wrapper(wrapper, f)
         return wrapper

‘wraps()’ is a decorator that can be used inside your own decorators to
copy the wrapped function’s information.  An alternate version of the
previous example would be:

     def my_decorator(f):
         @functools.wraps(f)
         def wrapper(*args, **kwds):
             print 'Calling decorated function'
             return f(*args, **kwds)
         return wrapper

See also
........

PEP 309(1) - Partial Function Application

     PEP proposed and written by Peter Harris; implemented by Hye-Shik
     Chang and Nick Coghlan, with adaptations by Raymond Hettinger.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0309/


File: python.info,  Node: PEP 314 Metadata for Python Software Packages v1 1,  Next: PEP 328 Absolute and Relative Imports,  Prev: PEP 309 Partial Function Application,  Up: What’s New in Python 2 5

1.17.3 PEP 314: Metadata for Python Software Packages v1.1
----------------------------------------------------------

Some simple dependency support was added to Distutils.  The ‘setup()’
function now has ‘requires’, ‘provides’, and ‘obsoletes’ keyword
parameters.  When you build a source distribution using the ‘sdist’
command, the dependency information will be recorded in the ‘PKG-INFO’
file.

Another new keyword parameter is ‘download_url’, which should be set to
a URL for the package’s source code.  This means it’s now possible to
look up an entry in the package index, determine the dependencies for a
package, and download the required packages.

     VERSION = '1.0'
     setup(name='PyPackage',
           version=VERSION,
           requires=['numarray', 'zlib (>=1.1.4)'],
           obsoletes=['OldPackage']
           download_url=('http://www.example.com/pypackage/dist/pkg-%s.tar.gz'
                         % VERSION),
          )

Another new enhancement to the Python package index at
‘https://pypi.org’ is storing source and binary archives for a package.
The new ‘upload’ Distutils command will upload a package to the
repository.

Before a package can be uploaded, you must be able to build a
distribution using the ‘sdist’ Distutils command.  Once that works, you
can run ‘python setup.py upload’ to add your package to the PyPI
archive.  Optionally you can GPG-sign the package by supplying the
‘--sign’ and ‘--identity’ options.

Package uploading was implemented by Martin von Löwis and Richard Jones.

See also
........

PEP 314(1) - Metadata for Python Software Packages v1.1

     PEP proposed and written by A.M. Kuchling, Richard Jones, and Fred
     Drake; implemented by Richard Jones and Fred Drake.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0314/


File: python.info,  Node: PEP 328 Absolute and Relative Imports,  Next: PEP 338 Executing Modules as Scripts,  Prev: PEP 314 Metadata for Python Software Packages v1 1,  Up: What’s New in Python 2 5

1.17.4 PEP 328: Absolute and Relative Imports
---------------------------------------------

The simpler part of PEP 328(1) was implemented in Python 2.4:
parentheses could now be used to enclose the names imported from a
module using the ‘from ... import ...’ statement, making it easier to
import many different names.

The more complicated part has been implemented in Python 2.5: importing
a module can be specified to use absolute or package-relative imports.
The plan is to move toward making absolute imports the default in future
versions of Python.

Let’s say you have a package directory like this:

     pkg/
     pkg/__init__.py
     pkg/main.py
     pkg/string.py

This defines a package named ‘pkg’ containing the ‘pkg.main’ and
‘pkg.string’ submodules.

Consider the code in the ‘main.py’ module.  What happens if it executes
the statement ‘import string’?  In Python 2.4 and earlier, it will first
look in the package’s directory to perform a relative import, finds
‘pkg/string.py’, imports the contents of that file as the ‘pkg.string’
module, and that module is bound to the name ‘string’ in the ‘pkg.main’
module’s namespace.

That’s fine if ‘pkg.string’ was what you wanted.  But what if you wanted
Python’s standard *note string: d3. module?  There’s no clean way to
ignore ‘pkg.string’ and look for the standard module; generally you had
to look at the contents of ‘sys.modules’, which is slightly unclean.
Holger Krekel’s ‘py.std’ package provides a tidier way to perform
imports from the standard library, ‘import py; py.std.string.join()’,
but that package isn’t available on all Python installations.

Reading code which relies on relative imports is also less clear,
because a reader may be confused about which module, *note string: d3.
or ‘pkg.string’, is intended to be used.  Python users soon learned not
to duplicate the names of standard library modules in the names of their
packages’ submodules, but you can’t protect against having your
submodule’s name being used for a new module added in a future version
of Python.

In Python 2.5, you can switch *note import: 5e5.’s behaviour to absolute
imports using a ‘from __future__ import absolute_import’ directive.
This absolute-import behaviour will become the default in a future
version (probably Python 2.7).  Once absolute imports are the default,
‘import string’ will always find the standard library’s version.  It’s
suggested that users should begin using absolute imports as much as
possible, so it’s preferable to begin writing ‘from pkg import string’
in your code.

Relative imports are still possible by adding a leading period to the
module name when using the ‘from ... import’ form:

     # Import names from pkg.string
     from .string import name1, name2
     # Import pkg.string
     from . import string

This imports the *note string: d3. module relative to the current
package, so in ‘pkg.main’ this will import 'name1' and 'name2' from
‘pkg.string’.  Additional leading periods perform the relative import
starting from the parent of the current package.  For example, code in
the ‘A.B.C’ module can do:

     from . import D                 # Imports A.B.D
     from .. import E                # Imports A.E
     from ..F import G               # Imports A.F.G

Leading periods cannot be used with the ‘import modname’ form of the
import statement, only the ‘from ... import’ form.

See also
........

PEP 328(2) - Imports: Multi-Line and Absolute/Relative

     PEP written by Aahz; implemented by Thomas Wouters.

‘https://pylib.readthedocs.io/’

     The py library by Holger Krekel, which contains the ‘py.std’
     package.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0328/

   (2) https://peps.python.org/pep-0328/


File: python.info,  Node: PEP 338 Executing Modules as Scripts,  Next: PEP 341 Unified try/except/finally,  Prev: PEP 328 Absolute and Relative Imports,  Up: What’s New in Python 2 5

1.17.5 PEP 338: Executing Modules as Scripts
--------------------------------------------

The *note -m: 5e4. switch added in Python 2.4 to execute a module as a
script gained a few more abilities.  Instead of being implemented in C
code inside the Python interpreter, the switch now uses an
implementation in a new module, *note runpy: be.

The *note runpy: be. module implements a more sophisticated import
mechanism so that it’s now possible to run modules in a package such as
‘pychecker.checker’.  The module also supports alternative import
mechanisms such as the *note zipimport: 132. module.  This means you can
add a .zip archive’s path to ‘sys.path’ and then use the *note -m: 5e4.
switch to execute code from the archive.

See also
........

PEP 338(1) - Executing modules as scripts

     PEP written and implemented by Nick Coghlan.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0338/


File: python.info,  Node: PEP 341 Unified try/except/finally,  Next: PEP 342 New Generator Features,  Prev: PEP 338 Executing Modules as Scripts,  Up: What’s New in Python 2 5

1.17.6 PEP 341: Unified try/except/finally
------------------------------------------

Until Python 2.5, the *note try: 6ec. statement came in two flavours.
You could use a *note finally: 9d5. block to ensure that code is always
executed, or one or more *note except: 18b. blocks to catch specific
exceptions.  You couldn’t combine both ‘except’ blocks and a ‘finally’
block, because generating the right bytecode for the combined version
was complicated and it wasn’t clear what the semantics of the combined
statement should be.

Guido van Rossum spent some time working with Java, which does support
the equivalent of combining *note except: 18b. blocks and a *note
finally: 9d5. block, and this clarified what the statement should mean.
In Python 2.5, you can now write:

     try:
         block-1 ...
     except Exception1:
         handler-1 ...
     except Exception2:
         handler-2 ...
     else:
         else-block
     finally:
         final-block

The code in 'block-1' is executed.  If the code raises an exception, the
various *note except: 18b. blocks are tested: if the exception is of
class ‘Exception1’, 'handler-1' is executed; otherwise if it’s of class
‘Exception2’, 'handler-2' is executed, and so forth.  If no exception is
raised, the 'else-block' is executed.

No matter what happened previously, the 'final-block' is executed once
the code block is complete and any raised exceptions handled.  Even if
there’s an error in an exception handler or the 'else-block' and a new
exception is raised, the code in the 'final-block' is still run.

See also
........

PEP 341(1) - Unifying try-except and try-finally

     PEP written by Georg Brandl; implementation by Thomas Lee.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0341/


File: python.info,  Node: PEP 342 New Generator Features,  Next: PEP 343 The ‘with’ statement<2>,  Prev: PEP 341 Unified try/except/finally,  Up: What’s New in Python 2 5

1.17.7 PEP 342: New Generator Features
--------------------------------------

Python 2.5 adds a simple way to pass values 'into' a generator.  As
introduced in Python 2.3, generators only produce output; once a
generator’s code was invoked to create an iterator, there was no way to
pass any new information into the function when its execution is
resumed.  Sometimes the ability to pass in some information would be
useful.  Hackish solutions to this include making the generator’s code
look at a global variable and then changing the global variable’s value,
or passing in some mutable object that callers then modify.

To refresh your memory of basic generators, here’s a simple example:

     def counter (maximum):
         i = 0
         while i < maximum:
             yield i
             i += 1

When you call ‘counter(10)’, the result is an iterator that returns the
values from 0 up to 9.  On encountering the *note yield: 9d8. statement,
the iterator returns the provided value and suspends the function’s
execution, preserving the local variables.  Execution resumes on the
following call to the iterator’s *note next(): 7dc. method, picking up
after the ‘yield’ statement.

In Python 2.3, *note yield: 9d8. was a statement; it didn’t return any
value.  In 2.5, ‘yield’ is now an expression, returning a value that can
be assigned to a variable or otherwise operated on:

     val = (yield i)

I recommend that you always put parentheses around a *note yield: 9d8.
expression when you’re doing something with the returned value, as in
the above example.  The parentheses aren’t always necessary, but it’s
easier to always add them instead of having to remember when they’re
needed.

( PEP 342(1) explains the exact rules, which are that a *note yield:
9d8.-expression must always be parenthesized except when it occurs at
the top-level expression on the right-hand side of an assignment.  This
means you can write ‘val = yield i’ but have to use parentheses when
there’s an operation, as in ‘val = (yield i) + 12’.)

Values are sent into a generator by calling its ‘send(value)’ method.
The generator’s code is then resumed and the *note yield: 9d8.
expression returns the specified 'value'.  If the regular *note next():
7dc. method is called, the ‘yield’ returns *note None: 678.

Here’s the previous example, modified to allow changing the value of the
internal counter.

     def counter (maximum):
         i = 0
         while i < maximum:
             val = (yield i)
             # If value provided, change counter
             if val is not None:
                 i = val
             else:
                 i += 1

And here’s an example of changing the counter:

     >>> it = counter(10)
     >>> print it.next()
     0
     >>> print it.next()
     1
     >>> print it.send(8)
     8
     >>> print it.next()
     9
     >>> print it.next()
     Traceback (most recent call last):
       File "t.py", line 15, in ?
         print it.next()
     StopIteration

*note yield: 9d8. will usually return *note None: 678, so you should
always check for this case.  Don’t just use its value in expressions
unless you’re sure that the ‘send()’ method will be the only method used
to resume your generator function.

In addition to ‘send()’, there are two other new methods on generators:

   * ‘throw(type, value=None, traceback=None)’ is used to raise an
     exception inside the generator; the exception is raised by the
     *note yield: 9d8. expression where the generator’s execution is
     paused.

   * ‘close()’ raises a new *note GeneratorExit: 1414. exception inside
     the generator to terminate the iteration.  On receiving this
     exception, the generator’s code must either raise ‘GeneratorExit’
     or *note StopIteration: c1b.  Catching the ‘GeneratorExit’
     exception and returning a value is illegal and will trigger a *note
     RuntimeError: 195.; if the function raises some other exception,
     that exception is propagated to the caller.  ‘close()’ will also be
     called by Python’s garbage collector when the generator is
     garbage-collected.

     If you need to run cleanup code when a *note GeneratorExit: 1414.
     occurs, I suggest using a ‘try: ... finally:’ suite instead of
     catching ‘GeneratorExit’.

The cumulative effect of these changes is to turn generators from
one-way producers of information into both producers and consumers.

Generators also become 'coroutines', a more generalized form of
subroutines.  Subroutines are entered at one point and exited at another
point (the top of the function, and a *note return: 9d9. statement), but
coroutines can be entered, exited, and resumed at many different points
(the *note yield: 9d8. statements).  We’ll have to figure out patterns
for using coroutines effectively in Python.

The addition of the ‘close()’ method has one side effect that isn’t
obvious.  ‘close()’ is called when a generator is garbage-collected, so
this means the generator’s code gets one last chance to run before the
generator is destroyed.  This last chance means that ‘try...finally’
statements in generators can now be guaranteed to work; the *note
finally: 9d5. clause will now always get a chance to run.  The syntactic
restriction that you couldn’t mix *note yield: 9d8. statements with a
‘try...finally’ suite has therefore been removed.  This seems like a
minor bit of language trivia, but using generators and ‘try...finally’
is actually necessary in order to implement the *note with: 5d5.
statement described by PEP 343(2).  I’ll look at this new statement in
the following section.

Another even more esoteric effect of this change: previously, the
‘gi_frame’ attribute of a generator was always a frame object.  It’s now
possible for ‘gi_frame’ to be ‘None’ once the generator has been
exhausted.

See also
........

PEP 342(3) - Coroutines via Enhanced Generators

     PEP written by Guido van Rossum and Phillip J. Eby; implemented by
     Phillip J. Eby.  Includes examples of some fancier uses of
     generators as coroutines.

     Earlier versions of these features were proposed in PEP 288(4) by
     Raymond Hettinger and PEP 325(5) by Samuele Pedroni.

‘https://en.wikipedia.org/wiki/Coroutine’

     The Wikipedia entry for coroutines.

‘https://web.archive.org/web/20160321211320/http://www.sidhe.org/~dan/blog/archives/000178.html’

     An explanation of coroutines from a Perl point of view, written by
     Dan Sugalski.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0342/

   (2) https://peps.python.org/pep-0343/

   (3) https://peps.python.org/pep-0342/

   (4) https://peps.python.org/pep-0288/

   (5) https://peps.python.org/pep-0325/


File: python.info,  Node: PEP 343 The ‘with’ statement<2>,  Next: PEP 352 Exceptions as New-Style Classes,  Prev: PEP 342 New Generator Features,  Up: What’s New in Python 2 5

1.17.8 PEP 343: The ‘with’ statement
------------------------------------

The ‘*note with: 5d5.’ statement clarifies code that previously would
use ‘try...finally’ blocks to ensure that clean-up code is executed.  In
this section, I’ll discuss the statement as it will commonly be used.
In the next section, I’ll examine the implementation details and show
how to write objects for use with this statement.

The ‘*note with: 5d5.’ statement is a new control-flow structure whose
basic structure is:

     with expression [as variable]:
         with-block

The expression is evaluated, and it should result in an object that
supports the context management protocol (that is, has *note
__enter__(): 5cb. and *note __exit__(): 1349. methods.

The object’s *note __enter__(): 5cb. is called before 'with-block' is
executed and therefore can run set-up code.  It also may return a value
that is bound to the name 'variable', if given.  (Note carefully that
'variable' is 'not' assigned the result of 'expression'.)

After execution of the 'with-block' is finished, the object’s *note
__exit__(): 1349. method is called, even if the block raised an
exception, and can therefore run clean-up code.

To enable the statement in Python 2.5, you need to add the following
directive to your module:

     from __future__ import with_statement

The statement will always be enabled in Python 2.6.

Some standard Python objects now support the context management protocol
and can be used with the ‘*note with: 5d5.’ statement.  File objects are
one example:

     with open('/etc/passwd', 'r') as f:
         for line in f:
             print line
             ... more processing code ...

After this statement has executed, the file object in 'f' will have been
automatically closed, even if the *note for: 2f2. loop raised an
exception part-way through the block.

     Note: In this case, 'f' is the same object created by *note open():
     51f, because *note __enter__(): 5cb. returns 'self'.

The *note threading: ed. module’s locks and condition variables also
support the ‘*note with: 5d5.’ statement:

     lock = threading.Lock()
     with lock:
         # Critical section of code
         ...

The lock is acquired before the block is executed and always released
once the block is complete.

The new ‘localcontext()’ function in the *note decimal: 36. module makes
it easy to save and restore the current decimal context, which
encapsulates the desired precision and rounding characteristics for
computations:

     from decimal import Decimal, Context, localcontext

     # Displays with default precision of 28 digits
     v = Decimal('578')
     print v.sqrt()

     with localcontext(Context(prec=16)):
         # All code in this block uses a precision of 16 digits.
         # The original context is restored on exiting the block.
         print v.sqrt()

* Menu:

* Writing Context Managers: Writing Context Managers<2>.
* The contextlib module: The contextlib module<2>.


File: python.info,  Node: Writing Context Managers<2>,  Next: The contextlib module<2>,  Up: PEP 343 The ‘with’ statement<2>

1.17.8.1 Writing Context Managers
.................................

Under the hood, the ‘*note with: 5d5.’ statement is fairly complicated.
Most people will only use ‘‘with’’ in company with existing objects and
don’t need to know these details, so you can skip the rest of this
section if you like.  Authors of new objects will need to understand the
details of the underlying implementation and should keep reading.

A high-level explanation of the context management protocol is:

   * The expression is evaluated and should result in an object called a
     “context manager”.  The context manager must have *note
     __enter__(): 5cb. and *note __exit__(): 1349. methods.

   * The context manager’s *note __enter__(): 5cb. method is called.
     The value returned is assigned to 'VAR'. If no ‘'as VAR'’ clause is
     present, the value is simply discarded.

   * The code in 'BLOCK' is executed.

   * If 'BLOCK' raises an exception, the ‘__exit__(type, value,
     traceback)’ is called with the exception details, the same values
     returned by *note sys.exc_info(): 68d.  The method’s return value
     controls whether the exception is re-raised: any false value
     re-raises the exception, and ‘True’ will result in suppressing it.
     You’ll only rarely want to suppress the exception, because if you
     do the author of the code containing the ‘*note with: 5d5.’
     statement will never realize anything went wrong.

   * If 'BLOCK' didn’t raise an exception, the *note __exit__(): 1349.
     method is still called, but 'type', 'value', and 'traceback' are
     all ‘None’.

Let’s think through an example.  I won’t present detailed code but will
only sketch the methods necessary for a database that supports
transactions.

(For people unfamiliar with database terminology: a set of changes to
the database are grouped into a transaction.  Transactions can be either
committed, meaning that all the changes are written into the database,
or rolled back, meaning that the changes are all discarded and the
database is unchanged.  See any database textbook for more information.)

Let’s assume there’s an object representing a database connection.  Our
goal will be to let the user write code like this:

     db_connection = DatabaseConnection()
     with db_connection as cursor:
         cursor.execute('insert into ...')
         cursor.execute('delete from ...')
         # ... more operations ...

The transaction should be committed if the code in the block runs
flawlessly or rolled back if there’s an exception.  Here’s the basic
interface for ‘DatabaseConnection’ that I’ll assume:

     class DatabaseConnection:
         # Database interface
         def cursor (self):
             "Returns a cursor object and starts a new transaction"
         def commit (self):
             "Commits current transaction"
         def rollback (self):
             "Rolls back current transaction"

The *note __enter__(): 5cb. method is pretty easy, having only to start
a new transaction.  For this application the resulting cursor object
would be a useful result, so the method will return it.  The user can
then add ‘as cursor’ to their ‘*note with: 5d5.’ statement to bind the
cursor to a variable name.

     class DatabaseConnection:
         ...
         def __enter__ (self):
             # Code to start a new transaction
             cursor = self.cursor()
             return cursor

The *note __exit__(): 1349. method is the most complicated because it’s
where most of the work has to be done.  The method has to check if an
exception occurred.  If there was no exception, the transaction is
committed.  The transaction is rolled back if there was an exception.

In the code below, execution will just fall off the end of the function,
returning the default value of ‘None’.  ‘None’ is false, so the
exception will be re-raised automatically.  If you wished, you could be
more explicit and add a *note return: 9d9. statement at the marked
location.

     class DatabaseConnection:
         ...
         def __exit__ (self, type, value, tb):
             if tb is None:
                 # No exception, so commit
                 self.commit()
             else:
                 # Exception occurred, so rollback.
                 self.rollback()
                 # return False


File: python.info,  Node: The contextlib module<2>,  Prev: Writing Context Managers<2>,  Up: PEP 343 The ‘with’ statement<2>

1.17.8.2 The contextlib module
..............................

The new *note contextlib: 23. module provides some functions and a
decorator that are useful for writing objects for use with the ‘*note
with: 5d5.’ statement.

The decorator is called ‘contextmanager()’, and lets you write a single
generator function instead of defining a new class.  The generator
should yield exactly one value.  The code up to the *note yield: 9d8.
will be executed as the *note __enter__(): 5cb. method, and the value
yielded will be the method’s return value that will get bound to the
variable in the ‘*note with: 5d5.’ statement’s ‘as’ clause, if any.  The
code after the ‘yield’ will be executed in the *note __exit__(): 1349.
method.  Any exception raised in the block will be raised by the ‘yield’
statement.

Our database example from the previous section could be written using
this decorator as:

     from contextlib import contextmanager

     @contextmanager
     def db_transaction (connection):
         cursor = connection.cursor()
         try:
             yield cursor
         except:
             connection.rollback()
             raise
         else:
             connection.commit()

     db = DatabaseConnection()
     with db_transaction(db) as cursor:
         ...

The *note contextlib: 23. module also has a ‘nested(mgr1, mgr2, ...)’
function that combines a number of context managers so you don’t need to
write nested ‘*note with: 5d5.’ statements.  In this example, the single
‘‘with’’ statement both starts a database transaction and acquires a
thread lock:

     lock = threading.Lock()
     with nested (db_transaction(db), lock) as (cursor, locked):
         ...

Finally, the ‘closing(object)’ function returns 'object' so that it can
be bound to a variable, and calls ‘object.close’ at the end of the
block.

     import urllib, sys
     from contextlib import closing

     with closing(urllib.urlopen('http://www.yahoo.com')) as f:
         for line in f:
             sys.stdout.write(line)

See also
........

PEP 343(1) - The “with” statement

     PEP written by Guido van Rossum and Nick Coghlan; implemented by
     Mike Bland, Guido van Rossum, and Neal Norwitz.  The PEP shows the
     code generated for a ‘*note with: 5d5.’ statement, which can be
     helpful in learning how the statement works.

The documentation for the *note contextlib: 23. module.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0343/


File: python.info,  Node: PEP 352 Exceptions as New-Style Classes,  Next: PEP 353 Using ssize_t as the index type,  Prev: PEP 343 The ‘with’ statement<2>,  Up: What’s New in Python 2 5

1.17.9 PEP 352: Exceptions as New-Style Classes
-----------------------------------------------

Exception classes can now be new-style classes, not just classic
classes, and the built-in *note Exception: 9e5. class and all the
standard built-in exceptions (*note NameError: 442, *note ValueError:
202, etc.)  are now new-style classes.

The inheritance hierarchy for exceptions has been rearranged a bit.  In
2.5, the inheritance relationships are:

     BaseException       # New in Python 2.5
     |- KeyboardInterrupt
     |- SystemExit
     |- Exception
        |- (all other current built-in exceptions)

This rearrangement was done because people often want to catch all
exceptions that indicate program errors.  *note KeyboardInterrupt: 9dc.
and *note SystemExit: d69. aren’t errors, though, and usually represent
an explicit action such as the user hitting ‘Control’-‘C’ or code
calling *note sys.exit(): 1394.  A bare ‘except:’ will catch all
exceptions, so you commonly need to list ‘KeyboardInterrupt’ and
‘SystemExit’ in order to re-raise them.  The usual pattern is:

     try:
         ...
     except (KeyboardInterrupt, SystemExit):
         raise
     except:
         # Log error...
         # Continue running program...

In Python 2.5, you can now write ‘except Exception’ to achieve the same
result, catching all the exceptions that usually indicate errors but
leaving *note KeyboardInterrupt: 9dc. and *note SystemExit: d69. alone.
As in previous versions, a bare ‘except:’ still catches all exceptions.

The goal for Python 3.0 is to require any class raised as an exception
to derive from *note BaseException: 5be. or some descendant of
‘BaseException’, and future releases in the Python 2.x series may begin
to enforce this constraint.  Therefore, I suggest you begin making all
your exception classes derive from *note Exception: 9e5. now.  It’s been
suggested that the bare ‘except:’ form should be removed in Python 3.0,
but Guido van Rossum hasn’t decided whether to do this or not.

Raising of strings as exceptions, as in the statement ‘raise "Error
occurred"’, is deprecated in Python 2.5 and will trigger a warning.  The
aim is to be able to remove the string-exception feature in a few
releases.

See also
........

PEP 352(1) - Required Superclass for Exceptions

     PEP written by Brett Cannon and Guido van Rossum; implemented by
     Brett Cannon.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0352/


File: python.info,  Node: PEP 353 Using ssize_t as the index type,  Next: PEP 357 The ‘__index__’ method,  Prev: PEP 352 Exceptions as New-Style Classes,  Up: What’s New in Python 2 5

1.17.10 PEP 353: Using ssize_t as the index type
------------------------------------------------

A wide-ranging change to Python’s C API, using a new *note Py_ssize_t:
a6e. type definition instead of int, will permit the interpreter to
handle more data on 64-bit platforms.  This change doesn’t affect
Python’s capacity on 32-bit platforms.

Various pieces of the Python interpreter used C’s int type to store
sizes or counts; for example, the number of items in a list or tuple
were stored in an int.  The C compilers for most 64-bit platforms still
define int as a 32-bit type, so that meant that lists could only hold up
to ‘2**31 - 1’ = 2147483647 items.  (There are actually a few different
programming models that 64-bit C compilers can use – see
‘https://unix.org/version2/whatsnew/lp64_wp.html’ for a discussion – but
the most commonly available model leaves int as 32 bits.)

A limit of 2147483647 items doesn’t really matter on a 32-bit platform
because you’ll run out of memory before hitting the length limit.  Each
list item requires space for a pointer, which is 4 bytes, plus space for
a *note PyObject: 33a. representing the item.  2147483647*4 is already
more bytes than a 32-bit address space can contain.

It’s possible to address that much memory on a 64-bit platform, however.
The pointers for a list that size would only require 16 GiB of space, so
it’s not unreasonable that Python programmers might construct lists that
large.  Therefore, the Python interpreter had to be changed to use some
type other than int, and this will be a 64-bit type on 64-bit platforms.
The change will cause incompatibilities on 64-bit machines, so it was
deemed worth making the transition now, while the number of 64-bit users
is still relatively small.  (In 5 or 10 years, we may 'all' be on 64-bit
machines, and the transition would be more painful then.)

This change most strongly affects authors of C extension modules.
Python strings and container types such as lists and tuples now use
*note Py_ssize_t: a6e. to store their size.  Functions such as *note
PyList_Size(): 1468. now return ‘Py_ssize_t’.  Code in extension modules
may therefore need to have some variables changed to ‘Py_ssize_t’.

The *note PyArg_ParseTuple(): 574. and *note Py_BuildValue(): 8af.
functions have a new conversion code, ‘n’, for *note Py_ssize_t: a6e.
‘PyArg_ParseTuple()’’s ‘s#’ and ‘t#’ still output int by default, but
you can define the macro ‘PY_SSIZE_T_CLEAN’ before including ‘Python.h’
to make them return ‘Py_ssize_t’.

PEP 353(1) has a section on conversion guidelines that extension authors
should read to learn about supporting 64-bit platforms.

See also
........

PEP 353(2) - Using ssize_t as the index type

     PEP written and implemented by Martin von Löwis.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0353/

   (2) https://peps.python.org/pep-0353/


File: python.info,  Node: PEP 357 The ‘__index__’ method,  Next: Other Language Changes<16>,  Prev: PEP 353 Using ssize_t as the index type,  Up: What’s New in Python 2 5

1.17.11 PEP 357: The ‘__index__’ method
---------------------------------------

The NumPy developers had a problem that could only be solved by adding a
new special method, ‘__index__()’.  When using slice notation, as in
‘[start:stop:step]’, the values of the 'start', 'stop', and 'step'
indexes must all be either integers or long integers.  NumPy defines a
variety of specialized integer types corresponding to unsigned and
signed integers of 8, 16, 32, and 64 bits, but there was no way to
signal that these types could be used as slice indexes.

Slicing can’t just use the existing ‘__int__()’ method because that
method is also used to implement coercion to integers.  If slicing used
‘__int__()’, floating-point numbers would also become legal slice
indexes and that’s clearly an undesirable behaviour.

Instead, a new special method called ‘__index__()’ was added.  It takes
no arguments and returns an integer giving the slice index to use.  For
example:

     class C:
         def __index__ (self):
             return self.value

The return value must be either a Python integer or long integer.  The
interpreter will check that the type returned is correct, and raises a
*note TypeError: 2c3. if this requirement isn’t met.

A corresponding *note nb_index: 146b. slot was added to the C-level
*note PyNumberMethods: 146c. structure to let C extensions implement
this protocol.  ‘PyNumber_Index(obj)’ can be used in extension code to
call the ‘__index__()’ function and retrieve its result.

See also
........

PEP 357(1) - Allowing Any Object to be Used for Slicing

     PEP written and implemented by Travis Oliphant.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0357/


File: python.info,  Node: Other Language Changes<16>,  Next: New Improved and Removed Modules,  Prev: PEP 357 The ‘__index__’ method,  Up: What’s New in Python 2 5

1.17.12 Other Language Changes
------------------------------

Here are all of the changes that Python 2.5 makes to the core Python
language.

   * The *note dict: 256. type has a new hook for letting subclasses
     provide a default value when a key isn’t contained in the
     dictionary.  When a key isn’t found, the dictionary’s
     ‘__missing__(key)’ method will be called.  This hook is used to
     implement the new ‘defaultdict’ class in the *note collections: 1d.
     module.  The following example defines a dictionary that returns
     zero for any missing key:

          class zerodict (dict):
              def __missing__ (self, key):
                  return 0

          d = zerodict({1:1, 2:2})
          print d[1], d[2]   # Prints 1, 2
          print d[3], d[4]   # Prints 0, 0

   * Both 8-bit and Unicode strings have new ‘partition(sep)’ and
     ‘rpartition(sep)’ methods that simplify a common use case.

     The ‘find(S)’ method is often used to get an index which is then
     used to slice the string and obtain the pieces that are before and
     after the separator.  ‘partition(sep)’ condenses this pattern into
     a single method call that returns a 3-tuple containing the
     substring before the separator, the separator itself, and the
     substring after the separator.  If the separator isn’t found, the
     first element of the tuple is the entire string and the other two
     elements are empty.  ‘rpartition(sep)’ also returns a 3-tuple but
     starts searching from the end of the string; the ‘r’ stands for
     ‘reverse’.

     Some examples:

          >>> ('http://www.python.org').partition('://')
          ('http', '://', 'www.python.org')
          >>> ('file:/usr/share/doc/index.html').partition('://')
          ('file:/usr/share/doc/index.html', '', '')
          >>> (u'Subject: a quick question').partition(':')
          (u'Subject', u':', u' a quick question')
          >>> 'www.python.org'.rpartition('.')
          ('www.python', '.', 'org')
          >>> 'www.python.org'.rpartition(':')
          ('', '', 'www.python.org')

     (Implemented by Fredrik Lundh following a suggestion by Raymond
     Hettinger.)

   * The ‘startswith()’ and ‘endswith()’ methods of string types now
     accept tuples of strings to check for.

          def is_image_file (filename):
              return filename.endswith(('.gif', '.jpg', '.tiff'))

     (Implemented by Georg Brandl following a suggestion by Tom Lynn.)

   * The *note min(): f3f. and *note max(): f40. built-in functions
     gained a ‘key’ keyword parameter analogous to the ‘key’ argument
     for ‘sort()’.  This parameter supplies a function that takes a
     single argument and is called for every value in the list;
     ‘min()’/‘max()’ will return the element with the smallest/largest
     return value from this function.  For example, to find the longest
     string in a list, you can do:

          L = ['medium', 'longest', 'short']
          # Prints 'longest'
          print max(L, key=len)
          # Prints 'short', because lexicographically 'short' has the largest value
          print max(L)

     (Contributed by Steven Bethard and Raymond Hettinger.)

   * Two new built-in functions, *note any(): 146f. and *note all():
     1470, evaluate whether an iterator contains any true or false
     values.  ‘any()’ returns *note True: c2d. if any value returned by
     the iterator is true; otherwise it will return *note False: b4f.
     ‘all()’ returns ‘True’ only if all of the values returned by the
     iterator evaluate as true.  (Suggested by Guido van Rossum, and
     implemented by Raymond Hettinger.)

   * The result of a class’s ‘__hash__()’ method can now be either a
     long integer or a regular integer.  If a long integer is returned,
     the hash of that value is taken.  In earlier versions the hash
     value was required to be a regular integer, but in 2.5 the *note
     id(): 1471. built-in was changed to always return non-negative
     numbers, and users often seem to use ‘id(self)’ in ‘__hash__()’
     methods (though this is discouraged).

   * ASCII is now the default encoding for modules.  It’s now a syntax
     error if a module contains string literals with 8-bit characters
     but doesn’t have an encoding declaration.  In Python 2.4 this
     triggered a warning, not a syntax error.  See PEP 263(1) for how to
     declare a module’s encoding; for example, you might add a line like
     this near the top of the source file:

          # -*- coding: latin1 -*-

   * A new warning, *note UnicodeWarning: 1472, is triggered when you
     attempt to compare a Unicode string and an 8-bit string that can’t
     be converted to Unicode using the default ASCII encoding.  The
     result of the comparison is false:

          >>> chr(128) == unichr(128)   # Can't convert chr(128) to Unicode
          __main__:1: UnicodeWarning: Unicode equal comparison failed
            to convert both arguments to Unicode - interpreting them
            as being unequal
          False
          >>> chr(127) == unichr(127)   # chr(127) can be converted
          True

     Previously this would raise a *note UnicodeDecodeError: a20.
     exception, but in 2.5 this could result in puzzling problems when
     accessing a dictionary.  If you looked up ‘unichr(128)’ and
     ‘chr(128)’ was being used as a key, you’d get a
     ‘UnicodeDecodeError’ exception.  Other changes in 2.5 resulted in
     this exception being raised instead of suppressed by the code in
     ‘dictobject.c’ that implements dictionaries.

     Raising an exception for such a comparison is strictly correct, but
     the change might have broken code, so instead *note UnicodeWarning:
     1472. was introduced.

     (Implemented by Marc-André Lemburg.)

   * One error that Python programmers sometimes make is forgetting to
     include an ‘__init__.py’ module in a package directory.  Debugging
     this mistake can be confusing, and usually requires running Python
     with the *note -v: 1473. switch to log all the paths searched.  In
     Python 2.5, a new *note ImportWarning: 4fd. warning is triggered
     when an import would have picked up a directory as a package but no
     ‘__init__.py’ was found.  This warning is silently ignored by
     default; provide the *note -Wd: 8d0. option when running the Python
     executable to display the warning message.  (Implemented by Thomas
     Wouters.)

   * The list of base classes in a class definition can now be empty.
     As an example, this is now legal:

          class C():
              pass

     (Implemented by Brett Cannon.)

* Menu:

* Interactive Interpreter Changes::
* Optimizations: Optimizations<15>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0263/


File: python.info,  Node: Interactive Interpreter Changes,  Next: Optimizations<15>,  Up: Other Language Changes<16>

1.17.12.1 Interactive Interpreter Changes
.........................................

In the interactive interpreter, ‘quit’ and ‘exit’ have long been strings
so that new users get a somewhat helpful message when they try to quit:

     >>> quit
     'Use Ctrl-D (i.e. EOF) to exit.'

In Python 2.5, ‘quit’ and ‘exit’ are now objects that still produce
string representations of themselves, but are also callable.  Newbies
who try ‘quit()’ or ‘exit()’ will now exit the interpreter as they
expect.  (Implemented by Georg Brandl.)

The Python executable now accepts the standard long options *note -help:
5f3. and *note -version: d43.; on Windows, it also accepts the *note /?:
1476. option for displaying a help message.  (Implemented by Georg
Brandl.)


File: python.info,  Node: Optimizations<15>,  Prev: Interactive Interpreter Changes,  Up: Other Language Changes<16>

1.17.12.2 Optimizations
.......................

Several of the optimizations were developed at the NeedForSpeed sprint,
an event held in Reykjavik, Iceland, from May 21–28 2006.  The sprint
focused on speed enhancements to the CPython implementation and was
funded by EWT LLC with local support from CCP Games.  Those
optimizations added at this sprint are specially marked in the following
list.

   * When they were introduced in Python 2.4, the built-in *note set:
     5dc. and *note frozenset: 5dd. types were built on top of Python’s
     dictionary type.  In 2.5 the internal data structure has been
     customized for implementing sets, and as a result sets will use a
     third less memory and are somewhat faster.  (Implemented by Raymond
     Hettinger.)

   * The speed of some Unicode operations, such as finding substrings,
     string splitting, and character map encoding and decoding, has been
     improved.  (Substring search and splitting improvements were added
     by Fredrik Lundh and Andrew Dalke at the NeedForSpeed sprint.
     Character maps were improved by Walter Dörwald and Martin von
     Löwis.)

   * The ‘long(str, base)’ function is now faster on long digit strings
     because fewer intermediate results are calculated.  The peak is for
     strings of around 800–1000 digits where the function is 6 times
     faster.  (Contributed by Alan McIntyre and committed at the
     NeedForSpeed sprint.)

   * It’s now illegal to mix iterating over a file with ‘for line in
     file’ and calling the file object’s ‘read()’/*note readline():
     ba./‘readlines()’ methods.  Iteration uses an internal buffer and
     the ‘read*()’ methods don’t use that buffer.  Instead they would
     return the data following the buffer, causing the data to appear
     out of order.  Mixing iteration and these methods will now trigger
     a *note ValueError: 202. from the ‘read*()’ method.  (Implemented
     by Thomas Wouters.)

   * The *note struct: d5. module now compiles structure format strings
     into an internal representation and caches this representation,
     yielding a 20% speedup.  (Contributed by Bob Ippolito at the
     NeedForSpeed sprint.)

   * The *note re: b9. module got a 1 or 2% speedup by switching to
     Python’s allocator functions instead of the system’s ‘malloc()’ and
     ‘free()’.  (Contributed by Jack Diederich at the NeedForSpeed
     sprint.)

   * The code generator’s peephole optimizer now performs simple
     constant folding in expressions.  If you write something like ‘a =
     2+3’, the code generator will do the arithmetic and produce code
     corresponding to ‘a = 5’.  (Proposed and implemented by Raymond
     Hettinger.)

   * Function calls are now faster because code objects now keep the
     most recently finished frame (a “zombie frame”) in an internal
     field of the code object, reusing it the next time the code object
     is invoked.  (Original patch by Michael Hudson, modified by Armin
     Rigo and Richard Jones; committed at the NeedForSpeed sprint.)
     Frame objects are also slightly smaller, which may improve cache
     locality and reduce memory usage a bit.  (Contributed by Neal
     Norwitz.)

   * Python’s built-in exceptions are now new-style classes, a change
     that speeds up instantiation considerably.  Exception handling in
     Python 2.5 is therefore about 30% faster than in 2.4.  (Contributed
     by Richard Jones, Georg Brandl and Sean Reifschneider at the
     NeedForSpeed sprint.)

   * Importing now caches the paths tried, recording whether they exist
     or not so that the interpreter makes fewer ‘open()’ and ‘stat()’
     calls on startup.  (Contributed by Martin von Löwis and Georg
     Brandl.)


File: python.info,  Node: New Improved and Removed Modules,  Next: Build and C API Changes<10>,  Prev: Other Language Changes<16>,  Up: What’s New in Python 2 5

1.17.13 New, Improved, and Removed Modules
------------------------------------------

The standard library received many enhancements and bug fixes in Python
2.5.  Here’s a partial list of the most notable changes, sorted
alphabetically by module name.  Consult the ‘Misc/NEWS’ file in the
source tree for a more complete list of changes, or look through the SVN
logs for all the details.

   * The ‘audioop’ module now supports the a-LAW encoding, and the code
     for u-LAW encoding has been improved.  (Contributed by Lars
     Immisch.)

   * The *note codecs: 1b. module gained support for incremental codecs.
     The ‘codec.lookup()’ function now returns a ‘CodecInfo’ instance
     instead of a tuple.  ‘CodecInfo’ instances behave like a 4-tuple to
     preserve backward compatibility but also have the attributes
     ‘encode’, ‘decode’, ‘incrementalencoder’, ‘incrementaldecoder’,
     ‘streamwriter’, and ‘streamreader’.  Incremental codecs can receive
     input and produce output in multiple chunks; the output is the same
     as if the entire input was fed to the non-incremental codec.  See
     the ‘codecs’ module documentation for details.  (Designed and
     implemented by Walter Dörwald.)

   * The *note collections: 1d. module gained a new type, ‘defaultdict’,
     that subclasses the standard *note dict: 256. type.  The new type
     mostly behaves like a dictionary but constructs a default value
     when a key isn’t present, automatically adding it to the dictionary
     for the requested key value.

     The first argument to ‘defaultdict’’s constructor is a factory
     function that gets called whenever a key is requested but not
     found.  This factory function receives no arguments, so you can use
     built-in type constructors such as *note list(): 614. or *note
     int(): 257.  For example, you can make an index of words based on
     their initial letter like this:

          words = """Nel mezzo del cammin di nostra vita
          mi ritrovai per una selva oscura
          che la diritta via era smarrita""".lower().split()

          index = defaultdict(list)

          for w in words:
              init_letter = w[0]
              index[init_letter].append(w)

     Printing ‘index’ results in the following output:

          defaultdict(<type 'list'>, {'c': ['cammin', 'che'], 'e': ['era'],
                  'd': ['del', 'di', 'diritta'], 'm': ['mezzo', 'mi'],
                  'l': ['la'], 'o': ['oscura'], 'n': ['nel', 'nostra'],
                  'p': ['per'], 's': ['selva', 'smarrita'],
                  'r': ['ritrovai'], 'u': ['una'], 'v': ['vita', 'via']}

     (Contributed by Guido van Rossum.)

   * The ‘deque’ double-ended queue type supplied by the *note
     collections: 1d. module now has a ‘remove(value)’ method that
     removes the first occurrence of 'value' in the queue, raising *note
     ValueError: 202. if the value isn’t found.  (Contributed by Raymond
     Hettinger.)

   * New module: The *note contextlib: 23. module contains helper
     functions for use with the new ‘*note with: 5d5.’ statement.  See
     section *note The contextlib module: 1462. for more about this
     module.

   * New module: The *note cProfile: 27. module is a C implementation of
     the existing *note profile: af. module that has much lower
     overhead.  The module’s interface is the same as ‘profile’: you run
     ‘cProfile.run('main()')’ to profile a function, can save profile
     data to a file, etc.  It’s not yet known if the Hotshot profiler,
     which is also written in C but doesn’t match the ‘profile’ module’s
     interface, will continue to be maintained in future versions of
     Python.  (Contributed by Armin Rigo.)

     Also, the *note pstats: b0. module for analyzing the data measured
     by the profiler now supports directing the output to any file
     object by supplying a 'stream' argument to the ‘Stats’ constructor.
     (Contributed by Skip Montanaro.)

   * The *note csv: 29. module, which parses files in comma-separated
     value format, received several enhancements and a number of
     bugfixes.  You can now set the maximum size in bytes of a field by
     calling the ‘csv.field_size_limit(new_limit)’ function; omitting
     the 'new_limit' argument will return the currently set limit.  The
     ‘reader’ class now has a ‘line_num’ attribute that counts the
     number of physical lines read from the source; records can span
     multiple physical lines, so ‘line_num’ is not the same as the
     number of records read.

     The CSV parser is now stricter about multi-line quoted fields.
     Previously, if a line ended within a quoted field without a
     terminating newline character, a newline would be inserted into the
     returned field.  This behavior caused problems when reading files
     that contained carriage return characters within fields, so the
     code was changed to return the field without inserting newlines.
     As a consequence, if newlines embedded within fields are important,
     the input should be split into lines in a manner that preserves the
     newline characters.

     (Contributed by Skip Montanaro and Andrew McNamara.)

   * The *note datetime: 1cc. class in the *note datetime: 30. module
     now has a ‘strptime(string, format)’ method for parsing date
     strings, contributed by Josh Spoerri.  It uses the same format
     characters as *note time.strptime(): 147b. and *note
     time.strftime(): 122e.:

          import datetime as dt

          ts = dt.datetime.strptime('10:13:15 2006-03-07',
                                    '%H:%M:%S %Y-%m-%d')

   * The ‘SequenceMatcher.get_matching_blocks()’ method in the *note
     difflib: 37. module now guarantees to return a minimal list of
     blocks describing matching subsequences.  Previously, the algorithm
     would occasionally break a block of matching elements into two list
     entries.  (Enhancement by Tim Peters.)

   * The *note doctest: 3a. module gained a ‘SKIP’ option that keeps an
     example from being executed at all.  This is intended for code
     snippets that are usage examples intended for the reader and aren’t
     actually test cases.

     An 'encoding' parameter was added to the ‘testfile()’ function and
     the ‘DocFileSuite’ class to specify the file’s encoding.  This
     makes it easier to use non-ASCII characters in tests contained
     within a docstring.  (Contributed by Bjorn Tillenius.)

   * The *note email: 3b. package has been updated to version 4.0.
     (Contributed by Barry Warsaw.)

   * The *note fileinput: 5b. module was made more flexible.  Unicode
     filenames are now supported, and a 'mode' parameter that defaults
     to ‘"r"’ was added to the *note input(): 1320. function to allow
     opening files in binary or *note universal newlines: d62. mode.
     Another new parameter, 'openhook', lets you use a function other
     than *note open(): 51f. to open the input files.  Once you’re
     iterating over the set of files, the ‘FileInput’ object’s new *note
     fileno(): 147c. returns the file descriptor for the currently
     opened file.  (Contributed by Georg Brandl.)

   * In the *note gc: 60. module, the new ‘get_count()’ function returns
     a 3-tuple containing the current collection counts for the three GC
     generations.  This is accounting information for the garbage
     collector; when these counts reach a specified threshold, a garbage
     collection sweep will be made.  The existing *note gc.collect():
     a47. function now takes an optional 'generation' argument of 0, 1,
     or 2 to specify which generation to collect.  (Contributed by Barry
     Warsaw.)

   * The ‘nsmallest()’ and ‘nlargest()’ functions in the *note heapq:
     69. module now support a ‘key’ keyword parameter similar to the one
     provided by the *note min(): f3f./*note max(): f40. functions and
     the ‘sort()’ methods.  For example:

          >>> import heapq
          >>> L = ["short", 'medium', 'longest', 'longer still']
          >>> heapq.nsmallest(2, L)  # Return two lowest elements, lexicographically
          ['longer still', 'longest']
          >>> heapq.nsmallest(2, L, key=len)   # Return two shortest elements
          ['short', 'medium']

     (Contributed by Raymond Hettinger.)

   * The *note itertools.islice(): b67. function now accepts ‘None’ for
     the start and step arguments.  This makes it more compatible with
     the attributes of slice objects, so that you can now write the
     following:

          s = slice(5)     # Create slice object
          itertools.islice(iterable, s.start, s.stop, s.step)

     (Contributed by Raymond Hettinger.)

   * The *note format(): 622. function in the *note locale: 86. module
     has been modified and two new functions were added,
     ‘format_string()’ and ‘currency()’.

     The *note format(): 622. function’s 'val' parameter could
     previously be a string as long as no more than one %char specifier
     appeared; now the parameter must be exactly one %char specifier
     with no surrounding text.  An optional 'monetary' parameter was
     also added which, if ‘True’, will use the locale’s rules for
     formatting currency in placing a separator between groups of three
     digits.

     To format strings with multiple %char specifiers, use the new
     ‘format_string()’ function that works like *note format(): 622. but
     also supports mixing %char specifiers with arbitrary text.

     A new ‘currency()’ function was also added that formats a number
     according to the current locale’s settings.

     (Contributed by Georg Brandl.)

   * The *note mailbox: 8b. module underwent a massive rewrite to add
     the capability to modify mailboxes in addition to reading them.  A
     new set of classes that include ‘mbox’, ‘MH’, and ‘Maildir’ are
     used to read mailboxes, and have an ‘add(message)’ method to add
     messages, ‘remove(key)’ to remove messages, and ‘lock()’/‘unlock()’
     to lock/unlock the mailbox.  The following example converts a
     maildir-format mailbox into an mbox-format one:

          import mailbox

          # 'factory=None' uses email.Message.Message as the class representing
          # individual messages.
          src = mailbox.Maildir('maildir', factory=None)
          dest = mailbox.mbox('/tmp/mbox')

          for msg in src:
              dest.add(msg)

     (Contributed by Gregory K. Johnson.  Funding was provided by
     Google’s 2005 Summer of Code.)

   * New module: the ‘msilib’ module allows creating Microsoft Installer
     ‘.msi’ files and CAB files.  Some support for reading the ‘.msi’
     database is also included.  (Contributed by Martin von Löwis.)

   * The ‘nis’ module now supports accessing domains other than the
     system default domain by supplying a 'domain' argument to the
     ‘nis.match()’ and ‘nis.maps()’ functions.  (Contributed by Ben
     Bell.)

   * The *note operator: 9f. module’s ‘itemgetter()’ and ‘attrgetter()’
     functions now support multiple fields.  A call such as
     ‘operator.attrgetter('a', 'b')’ will return a function that
     retrieves the ‘a’ and ‘b’ attributes.  Combining this new feature
     with the ‘sort()’ method’s ‘key’ parameter lets you easily sort
     lists using multiple fields.  (Contributed by Raymond Hettinger.)

   * The *note optparse: a0. module was updated to version 1.5.1 of the
     Optik library.  The ‘OptionParser’ class gained an ‘epilog’
     attribute, a string that will be printed after the help message,
     and a ‘destroy()’ method to break reference cycles created by the
     object.  (Contributed by Greg Ward.)

   * The *note os: a1. module underwent several changes.  The
     ‘stat_float_times’ variable now defaults to true, meaning that
     *note os.stat(): 4a3. will now return time values as floats.  (This
     doesn’t necessarily mean that ‘os.stat()’ will return times that
     are precise to fractions of a second; not all systems support such
     precision.)

     Constants named *note os.SEEK_SET: 12d4, *note os.SEEK_CUR: 12d5,
     and *note os.SEEK_END: 12d6. have been added; these are the
     parameters to the *note os.lseek(): 115b. function.  Two new
     constants for locking are *note os.O_SHLOCK: 147d. and *note
     os.O_EXLOCK: 147e.

     Two new functions, ‘wait3()’ and ‘wait4()’, were added.  They’re
     similar the ‘waitpid()’ function which waits for a child process to
     exit and returns a tuple of the process ID and its exit status, but
     ‘wait3()’ and ‘wait4()’ return additional information.  ‘wait3()’
     doesn’t take a process ID as input, so it waits for any child
     process to exit and returns a 3-tuple of 'process-id',
     'exit-status', 'resource-usage' as returned from the *note
     resource.getrusage(): 147f. function.  ‘wait4(pid)’ does take a
     process ID. (Contributed by Chad J. Schroeder.)

     On FreeBSD, the *note os.stat(): 4a3. function now returns times
     with nanosecond resolution, and the returned object now has
     ‘st_gen’ and ‘st_birthtime’.  The ‘st_flags’ attribute is also
     available, if the platform supports it.  (Contributed by Antti
     Louko and Diego Pettenò.)

   * The Python debugger provided by the *note pdb: a5. module can now
     store lists of commands to execute when a breakpoint is reached and
     execution stops.  Once breakpoint #1 has been created, enter
     ‘commands 1’ and enter a series of commands to be executed,
     finishing the list with ‘end’.  The command list can include
     commands that resume execution, such as ‘continue’ or ‘next’.
     (Contributed by Grégoire Dooms.)

   * The *note pickle: a6. and ‘cPickle’ modules no longer accept a
     return value of ‘None’ from the *note __reduce__(): 9de. method;
     the method must return a tuple of arguments instead.  The ability
     to return ‘None’ was deprecated in Python 2.4, so this completes
     the removal of the feature.

   * The *note pkgutil: a9. module, containing various utility functions
     for finding packages, was enhanced to support PEP 302(1)’s import
     hooks and now also works for packages stored in ZIP-format
     archives.  (Contributed by Phillip J. Eby.)

   * The pybench benchmark suite by Marc-André Lemburg is now included
     in the ‘Tools/pybench’ directory.  The pybench suite is an
     improvement on the commonly used ‘pystone.py’ program because
     pybench provides a more detailed measurement of the interpreter’s
     speed.  It times particular operations such as function calls,
     tuple slicing, method lookups, and numeric operations, instead of
     performing many different operations and reducing the result to a
     single number as ‘pystone.py’ does.

   * The ‘pyexpat’ module now uses version 2.0 of the Expat parser.
     (Contributed by Trent Mick.)

   * The *note Queue: 13e1. class provided by the ‘Queue’ module gained
     two new methods.  ‘join()’ blocks until all items in the queue have
     been retrieved and all processing work on the items have been
     completed.  Worker threads call the other new method,
     ‘task_done()’, to signal that processing for an item has been
     completed.  (Contributed by Raymond Hettinger.)

   * The old ‘regex’ and ‘regsub’ modules, which have been deprecated
     ever since Python 2.0, have finally been deleted.  Other deleted
     modules: ‘statcache’, ‘tzparse’, ‘whrandom’.

   * Also deleted: the ‘lib-old’ directory, which includes ancient
     modules such as ‘dircmp’ and ‘ni’, was removed.  ‘lib-old’ wasn’t
     on the default ‘sys.path’, so unless your programs explicitly added
     the directory to ‘sys.path’, this removal shouldn’t affect your
     code.

   * The *note rlcompleter: bd. module is no longer dependent on
     importing the *note readline: ba. module and therefore now works on
     non-Unix platforms.  (Patch from Robert Kiendl.)

   * The *note SimpleXMLRPCServer: 12f. and ‘DocXMLRPCServer’ classes
     now have a ‘rpc_paths’ attribute that constrains XML-RPC operations
     to a limited set of URL paths; the default is to allow only ‘'/'’
     and ‘'/RPC2'’.  Setting ‘rpc_paths’ to ‘None’ or an empty tuple
     disables this path checking.

   * The *note socket: cc. module now supports ‘AF_NETLINK’ sockets on
     Linux, thanks to a patch from Philippe Biondi.  Netlink sockets are
     a Linux-specific mechanism for communications between a user-space
     process and kernel code; an introductory article about them is at
     ‘https://www.linuxjournal.com/article/7356’.  In Python code,
     netlink addresses are represented as a tuple of 2 integers, ‘(pid,
     group_mask)’.

     Two new methods on socket objects, ‘recv_into(buffer)’ and
     ‘recvfrom_into(buffer)’, store the received data in an object that
     supports the buffer protocol instead of returning the data as a
     string.  This means you can put the data directly into an array or
     a memory-mapped file.

     Socket objects also gained ‘getfamily()’, ‘gettype()’, and
     ‘getproto()’ accessor methods to retrieve the family, type, and
     protocol values for the socket.

   * New module: the ‘spwd’ module provides functions for accessing the
     shadow password database on systems that support shadow passwords.

   * The *note struct: d5. is now faster because it compiles format
     strings into ‘Struct’ objects with ‘pack()’ and ‘unpack()’ methods.
     This is similar to how the *note re: b9. module lets you create
     compiled regular expression objects.  You can still use the
     module-level ‘pack()’ and ‘unpack()’ functions; they’ll create
     ‘Struct’ objects and cache them.  Or you can use ‘Struct’ instances
     directly:

          s = struct.Struct('ih3s')

          data = s.pack(1972, 187, 'abc')
          year, number, name = s.unpack(data)

     You can also pack and unpack data to and from buffer objects
     directly using the ‘pack_into(buffer, offset, v1, v2, ...)’ and
     ‘unpack_from(buffer, offset)’ methods.  This lets you store data
     directly into an array or a memory-mapped file.

     (‘Struct’ objects were implemented by Bob Ippolito at the
     NeedForSpeed sprint.  Support for buffer objects was added by
     Martin Blais, also at the NeedForSpeed sprint.)

   * The Python developers switched from CVS to Subversion during the
     2.5 development process.  Information about the exact build version
     is available as the ‘sys.subversion’ variable, a 3-tuple of
     ‘(interpreter-name, branch-name, revision-range)’.  For example, at
     the time of writing my copy of 2.5 was reporting ‘('CPython',
     'trunk', '45313:45315')’.

     This information is also available to C extensions via the *note
     Py_GetBuildInfo(): 1480. function that returns a string of build
     information like this: ‘"trunk:45355:45356M, Apr 13 2006,
     07:42:19"’.  (Contributed by Barry Warsaw.)

   * Another new function, *note sys._current_frames(): 1481, returns
     the current stack frames for all running threads as a dictionary
     mapping thread identifiers to the topmost stack frame currently
     active in that thread at the time the function is called.
     (Contributed by Tim Peters.)

   * The ‘TarFile’ class in the *note tarfile: de. module now has an
     ‘extractall()’ method that extracts all members from the archive
     into the current working directory.  It’s also possible to set a
     different directory as the extraction target, and to unpack only a
     subset of the archive’s members.

     The compression used for a tarfile opened in stream mode can now be
     autodetected using the mode ‘'r|*'’.  (Contributed by Lars
     Gustäbel.)

   * The *note threading: ed. module now lets you set the stack size
     used when new threads are created.  The ‘stack_size([*size*])’
     function returns the currently configured stack size, and supplying
     the optional 'size' parameter sets a new value.  Not all platforms
     support changing the stack size, but Windows, POSIX threading, and
     OS/2 all do.  (Contributed by Andrew MacIntyre.)

   * The *note unicodedata: 105. module has been updated to use version
     4.1.0 of the Unicode character database.  Version 3.2.0 is required
     by some specifications, so it’s still available as *note
     unicodedata.ucd_3_2_0: 1482.

   * New module: the *note uuid: 110. module generates universally
     unique identifiers (UUIDs) according to RFC 4122(2).  The RFC
     defines several different UUID versions that are generated from a
     starting string, from system properties, or purely randomly.  This
     module contains a ‘UUID’ class and functions named ‘uuid1()’,
     ‘uuid3()’, ‘uuid4()’, and ‘uuid5()’ to generate different versions
     of UUID. (Version 2 UUIDs are not specified in RFC 4122(3) and are
     not supported by this module.)

          >>> import uuid
          >>> # make a UUID based on the host ID and current time
          >>> uuid.uuid1()
          UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')

          >>> # make a UUID using an MD5 hash of a namespace UUID and a name
          >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
          UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')

          >>> # make a random UUID
          >>> uuid.uuid4()
          UUID('16fd2706-8baf-433b-82eb-8c7fada847da')

          >>> # make a UUID using a SHA-1 hash of a namespace UUID and a name
          >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
          UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')

     (Contributed by Ka-Ping Yee.)

   * The *note weakref: 114. module’s ‘WeakKeyDictionary’ and
     ‘WeakValueDictionary’ types gained new methods for iterating over
     the weak references contained in the dictionary.  ‘iterkeyrefs()’
     and ‘keyrefs()’ methods were added to ‘WeakKeyDictionary’, and
     ‘itervaluerefs()’ and ‘valuerefs()’ were added to
     ‘WeakValueDictionary’.  (Contributed by Fred L. Drake, Jr.)

   * The *note webbrowser: 115. module received a number of
     enhancements.  It’s now usable as a script with ‘python -m
     webbrowser’, taking a URL as the argument; there are a number of
     switches to control the behaviour (‘-n’ for a new browser window,
     ‘-t’ for a new tab).  New module-level functions, ‘open_new()’ and
     ‘open_new_tab()’, were added to support this.  The module’s *note
     open(): 51f. function supports an additional feature, an
     'autoraise' parameter that signals whether to raise the open window
     when possible.  A number of additional browsers were added to the
     supported list such as Firefox, Opera, Konqueror, and elinks.
     (Contributed by Oleg Broytmann and Georg Brandl.)

   * The *note xmlrpclib: 12e. module now supports returning *note
     datetime: 1cc. objects for the XML-RPC date type.  Supply
     ‘use_datetime=True’ to the *note loads(): 1483. function or the
     ‘Unmarshaller’ class to enable this feature.  (Contributed by Skip
     Montanaro.)

   * The *note zipfile: 131. module now supports the ZIP64 version of
     the format, meaning that a .zip archive can now be larger than 4
     GiB and can contain individual files larger than 4 GiB.
     (Contributed by Ronald Oussoren.)

   * The *note zlib: 133. module’s ‘Compress’ and ‘Decompress’ objects
     now support a *note copy(): 25. method that makes a copy of the
     object’s internal state and returns a new ‘Compress’ or
     ‘Decompress’ object.  (Contributed by Chris AtLee.)

* Menu:

* The ctypes package::
* The ElementTree package::
* The hashlib package::
* The sqlite3 package::
* The wsgiref package::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0302/

   (2) https://datatracker.ietf.org/doc/html/rfc4122.html

   (3) https://datatracker.ietf.org/doc/html/rfc4122.html


File: python.info,  Node: The ctypes package,  Next: The ElementTree package,  Up: New Improved and Removed Modules

1.17.13.1 The ctypes package
............................

The *note ctypes: 2a. package, written by Thomas Heller, has been added
to the standard library.  ‘ctypes’ lets you call arbitrary functions in
shared libraries or DLLs.  Long-time users may remember the ‘dl’ module,
which provides functions for loading shared libraries and calling
functions in them.  The ‘ctypes’ package is much fancier.

To load a shared library or DLL, you must create an instance of the
‘CDLL’ class and provide the name or path of the shared library or DLL.
Once that’s done, you can call arbitrary functions by accessing them as
attributes of the ‘CDLL’ object.

     import ctypes

     libc = ctypes.CDLL('libc.so.6')
     result = libc.printf("Line of output\n")

Type constructors for the various C types are provided: ‘c_int()’,
‘c_float()’, ‘c_double()’, ‘c_char_p()’ (equivalent to char*), and so
forth.  Unlike Python’s types, the C versions are all mutable; you can
assign to their ‘value’ attribute to change the wrapped value.  Python
integers and strings will be automatically converted to the
corresponding C types, but for other types you must call the correct
type constructor.  (And I mean 'must'; getting it wrong will often
result in the interpreter crashing with a segmentation fault.)

You shouldn’t use ‘c_char_p()’ with a Python string when the C function
will be modifying the memory area, because Python strings are supposed
to be immutable; breaking this rule will cause puzzling bugs.  When you
need a modifiable memory area, use ‘create_string_buffer()’:

     s = "this is a string"
     buf = ctypes.create_string_buffer(s)
     libc.strfry(buf)

C functions are assumed to return integers, but you can set the
‘restype’ attribute of the function object to change this:

     >>> libc.atof('2.71828')
     -1783957616
     >>> libc.atof.restype = ctypes.c_double
     >>> libc.atof('2.71828')
     2.71828

*note ctypes: 2a. also provides a wrapper for Python’s C API as the
‘ctypes.pythonapi’ object.  This object does 'not' release the global
interpreter lock before calling a function, because the lock must be
held when calling into the interpreter’s code.  There’s a *note
py_object: 1486. type constructor that will create a *note PyObject:
33a.* pointer.  A simple usage:

     import ctypes

     d = {}
     ctypes.pythonapi.PyObject_SetItem(ctypes.py_object(d),
               ctypes.py_object("abc"),  ctypes.py_object(1))
     # d is now {'abc', 1}.

Don’t forget to use *note py_object(): 1486.; if it’s omitted you end up
with a segmentation fault.

*note ctypes: 2a. has been around for a while, but people still write
and distribution hand-coded extension modules because you can’t rely on
‘ctypes’ being present.  Perhaps developers will begin to write Python
wrappers atop a library accessed through ‘ctypes’ instead of extension
modules, now that ‘ctypes’ is included with core Python.

See also
........

‘https://web.archive.org/web/20180410025338/http://starship.python.net/crew/theller/ctypes/’

     The pre-stdlib ctypes web page, with a tutorial, reference, and
     FAQ.

The documentation for the *note ctypes: 2a. module.


File: python.info,  Node: The ElementTree package,  Next: The hashlib package,  Prev: The ctypes package,  Up: New Improved and Removed Modules

1.17.13.2 The ElementTree package
.................................

A subset of Fredrik Lundh’s ElementTree library for processing XML has
been added to the standard library as ‘xml.etree’.  The available
modules are ‘ElementTree’, ‘ElementPath’, and ‘ElementInclude’ from
ElementTree 1.2.6.  The ‘cElementTree’ accelerator module is also
included.

The rest of this section will provide a brief overview of using
ElementTree.  Full documentation for ElementTree is available at
‘https://web.archive.org/web/20201124024954/http://effbot.org/zone/element-index.htm’.

ElementTree represents an XML document as a tree of element nodes.  The
text content of the document is stored as the ‘text’ and ‘tail’
attributes of (This is one of the major differences between ElementTree
and the Document Object Model; in the DOM there are many different types
of node, including ‘TextNode’.)

The most commonly used parsing function is ‘parse()’, that takes either
a string (assumed to contain a filename) or a file-like object and
returns an ‘ElementTree’ instance:

     from xml.etree import ElementTree as ET

     tree = ET.parse('ex-1.xml')

     feed = urllib.urlopen(
               'http://planet.python.org/rss10.xml')
     tree = ET.parse(feed)

Once you have an ‘ElementTree’ instance, you can call its ‘getroot()’
method to get the root ‘Element’ node.

There’s also an ‘XML()’ function that takes a string literal and returns
an ‘Element’ node (not an ‘ElementTree’).  This function provides a tidy
way to incorporate XML fragments, approaching the convenience of an XML
literal:

     svg = ET.XML("""<svg width="10px" version="1.0">
                  </svg>""")
     svg.set('height', '320px')
     svg.append(elem1)

Each XML element supports some dictionary-like and some list-like access
methods.  Dictionary-like operations are used to access attribute
values, and list-like operations are used to access child nodes.

Operation                           Result
                                    
-------------------------------------------------------------------------------------
                                    
‘elem[n]’                           Returns n’th child element.
                                    
                                    
‘elem[m:n]’                         Returns list of m’th through n’th child
                                    elements.
                                    
                                    
‘len(elem)’                         Returns number of child elements.
                                    
                                    
‘list(elem)’                        Returns list of child elements.
                                    
                                    
‘elem.append(elem2)’                Adds 'elem2' as a child.
                                    
                                    
‘elem.insert(index, elem2)’         Inserts 'elem2' at the specified location.
                                    
                                    
‘del elem[n]’                       Deletes n’th child element.
                                    
                                    
‘elem.keys()’                       Returns list of attribute names.
                                    
                                    
‘elem.get(name)’                    Returns value of attribute 'name'.
                                    
                                    
‘elem.set(name, value)’             Sets new value for attribute 'name'.
                                    
                                    
‘elem.attrib’                       Retrieves the dictionary containing
                                    attributes.
                                    
                                    
‘del elem.attrib[name]’             Deletes attribute 'name'.
                                    

Comments and processing instructions are also represented as ‘Element’
nodes.  To check if a node is a comment or processing instructions:

     if elem.tag is ET.Comment:
         ...
     elif elem.tag is ET.ProcessingInstruction:
         ...

To generate XML output, you should call the ‘ElementTree.write()’
method.  Like ‘parse()’, it can take either a string or a file-like
object:

     # Encoding is US-ASCII
     tree.write('output.xml')

     # Encoding is UTF-8
     f = open('output.xml', 'w')
     tree.write(f, encoding='utf-8')

(Caution: the default encoding used for output is ASCII. For general XML
work, where an element’s name may contain arbitrary Unicode characters,
ASCII isn’t a very useful encoding because it will raise an exception if
an element’s name contains any characters with values greater than 127.
Therefore, it’s best to specify a different encoding such as UTF-8 that
can handle any Unicode character.)

This section is only a partial description of the ElementTree
interfaces.  Please read the package’s official documentation for more
details.

See also
........

‘https://web.archive.org/web/20201124024954/http://effbot.org/zone/element-index.htm’

     Official documentation for ElementTree.


File: python.info,  Node: The hashlib package,  Next: The sqlite3 package,  Prev: The ElementTree package,  Up: New Improved and Removed Modules

1.17.13.3 The hashlib package
.............................

A new *note hashlib: 68. module, written by Gregory P. Smith, has been
added to replace the ‘md5’ and ‘sha’ modules.  ‘hashlib’ adds support
for additional secure hashes (SHA-224, SHA-256, SHA-384, and SHA-512).
When available, the module uses OpenSSL for fast platform optimized
implementations of algorithms.

The old ‘md5’ and ‘sha’ modules still exist as wrappers around hashlib
to preserve backwards compatibility.  The new module’s interface is very
close to that of the old modules, but not identical.  The most
significant difference is that the constructor functions for creating
new hashing objects are named differently.

     # Old versions
     h = md5.md5()
     h = md5.new()

     # New version
     h = hashlib.md5()

     # Old versions
     h = sha.sha()
     h = sha.new()

     # New version
     h = hashlib.sha1()

     # Hash that weren't previously available
     h = hashlib.sha224()
     h = hashlib.sha256()
     h = hashlib.sha384()
     h = hashlib.sha512()

     # Alternative form
     h = hashlib.new('md5')          # Provide algorithm as a string

Once a hash object has been created, its methods are the same as before:
‘update(string)’ hashes the specified string into the current digest
state, ‘digest()’ and ‘hexdigest()’ return the digest value as a binary
string or a string of hex digits, and *note copy(): 25. returns a new
hashing object with the same digest state.

See also
........

The documentation for the *note hashlib: 68. module.


File: python.info,  Node: The sqlite3 package,  Next: The wsgiref package,  Prev: The hashlib package,  Up: New Improved and Removed Modules

1.17.13.4 The sqlite3 package
.............................

The pysqlite module (‘https://www.pysqlite.org’), a wrapper for the
SQLite embedded database, has been added to the standard library under
the package name *note sqlite3: cf.

SQLite is a C library that provides a lightweight disk-based database
that doesn’t require a separate server process and allows accessing the
database using a nonstandard variant of the SQL query language.  Some
applications can use SQLite for internal data storage.  It’s also
possible to prototype an application using SQLite and then port the code
to a larger database such as PostgreSQL or Oracle.

pysqlite was written by Gerhard Häring and provides a SQL interface
compliant with the DB-API 2.0 specification described by PEP 249(1).

If you’re compiling the Python source yourself, note that the source
tree doesn’t include the SQLite code, only the wrapper module.  You’ll
need to have the SQLite libraries and headers installed before compiling
Python, and the build process will compile the module when the necessary
headers are available.

To use the module, you must first create a ‘Connection’ object that
represents the database.  Here the data will be stored in the
‘/tmp/example’ file:

     conn = sqlite3.connect('/tmp/example')

You can also supply the special name ‘:memory:’ to create a database in
RAM.

Once you have a ‘Connection’, you can create a ‘Cursor’ object and call
its ‘execute()’ method to perform SQL commands:

     c = conn.cursor()

     # Create table
     c.execute('''create table stocks
     (date text, trans text, symbol text,
      qty real, price real)''')

     # Insert a row of data
     c.execute("""insert into stocks
               values ('2006-01-05','BUY','RHAT',100,35.14)""")

Usually your SQL operations will need to use values from Python
variables.  You shouldn’t assemble your query using Python’s string
operations because doing so is insecure; it makes your program
vulnerable to an SQL injection attack.

Instead, use the DB-API’s parameter substitution.  Put ‘?’ as a
placeholder wherever you want to use a value, and then provide a tuple
of values as the second argument to the cursor’s ‘execute()’ method.
(Other database modules may use a different placeholder, such as ‘%s’ or
‘:1’.)  For example:

     # Never do this -- insecure!
     symbol = 'IBM'
     c.execute("... where symbol = '%s'" % symbol)

     # Do this instead
     t = (symbol,)
     c.execute('select * from stocks where symbol=?', t)

     # Larger example
     for t in (('2006-03-28', 'BUY', 'IBM', 1000, 45.00),
               ('2006-04-05', 'BUY', 'MSOFT', 1000, 72.00),
               ('2006-04-06', 'SELL', 'IBM', 500, 53.00),
              ):
         c.execute('insert into stocks values (?,?,?,?,?)', t)

To retrieve data after executing a SELECT statement, you can either
treat the cursor as an iterator, call the cursor’s ‘fetchone()’ method
to retrieve a single matching row, or call ‘fetchall()’ to get a list of
the matching rows.

This example uses the iterator form:

     >>> c = conn.cursor()
     >>> c.execute('select * from stocks order by price')
     >>> for row in c:
     ...    print row
     ...
     (u'2006-01-05', u'BUY', u'RHAT', 100, 35.140000000000001)
     (u'2006-03-28', u'BUY', u'IBM', 1000, 45.0)
     (u'2006-04-06', u'SELL', u'IBM', 500, 53.0)
     (u'2006-04-05', u'BUY', u'MSOFT', 1000, 72.0)
     >>>

For more information about the SQL dialect supported by SQLite, see
‘https://www.sqlite.org’.

See also
........

‘https://www.pysqlite.org’

     The pysqlite web page.

‘https://www.sqlite.org’

     The SQLite web page; the documentation describes the syntax and the
     available data types for the supported SQL dialect.

The documentation for the *note sqlite3: cf. module.

PEP 249(2) - Database API Specification 2.0

     PEP written by Marc-André Lemburg.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0249/

   (2) https://peps.python.org/pep-0249/


File: python.info,  Node: The wsgiref package,  Prev: The sqlite3 package,  Up: New Improved and Removed Modules

1.17.13.5 The wsgiref package
.............................

The Web Server Gateway Interface (WSGI) v1.0 defines a standard
interface between web servers and Python web applications and is
described in PEP 333(1).  The *note wsgiref: 118. package is a reference
implementation of the WSGI specification.

The package includes a basic HTTP server that will run a WSGI
application; this server is useful for debugging but isn’t intended for
production use.  Setting up a server takes only a few lines of code:

     from wsgiref import simple_server

     wsgi_app = ...

     host = ''
     port = 8000
     httpd = simple_server.make_server(host, port, wsgi_app)
     httpd.serve_forever()

See also
........

‘https://web.archive.org/web/20160331090247/http://wsgi.readthedocs.org/en/latest/’

     A central web site for WSGI-related resources.

PEP 333(2) - Python Web Server Gateway Interface v1.0

     PEP written by Phillip J. Eby.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0333/

   (2) https://peps.python.org/pep-0333/


File: python.info,  Node: Build and C API Changes<10>,  Next: Porting to Python 2 5,  Prev: New Improved and Removed Modules,  Up: What’s New in Python 2 5

1.17.14 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * The Python source tree was converted from CVS to Subversion, in a
     complex migration procedure that was supervised and flawlessly
     carried out by Martin von Löwis.  The procedure was developed as
     PEP 347(1).

   * Coverity, a company that markets a source code analysis tool called
     Prevent, provided the results of their examination of the Python
     source code.  The analysis found about 60 bugs that were quickly
     fixed.  Many of the bugs were refcounting problems, often occurring
     in error-handling code.  See ‘https://scan.coverity.com’ for the
     statistics.

   * The largest change to the C API came from PEP 353(2), which
     modifies the interpreter to use a *note Py_ssize_t: a6e. type
     definition instead of int.  See the earlier section *note PEP 353;
     Using ssize_t as the index type: 1466. for a discussion of this
     change.

   * The design of the bytecode compiler has changed a great deal, no
     longer generating bytecode by traversing the parse tree.  Instead
     the parse tree is converted to an abstract syntax tree (or AST),
     and it is the abstract syntax tree that’s traversed to produce the
     bytecode.

     It’s possible for Python code to obtain AST objects by using the
     *note compile(): 192. built-in and specifying ‘_ast.PyCF_ONLY_AST’
     as the value of the 'flags' parameter:

          from _ast import PyCF_ONLY_AST
          ast = compile("""a=0
          for i in range(10):
              a += i
          """, "<string>", 'exec', PyCF_ONLY_AST)

          assignment = ast.body[0]
          for_loop = ast.body[1]

     No official documentation has been written for the AST code yet,
     but PEP 339(3) discusses the design.  To start learning about the
     code, read the definition of the various AST nodes in
     ‘Parser/Python.asdl’.  A Python script reads this file and
     generates a set of C structure definitions in
     ‘Include/Python-ast.h’.  The ‘PyParser_ASTFromString()’ and
     ‘PyParser_ASTFromFile()’, defined in ‘Include/pythonrun.h’, take
     Python source as input and return the root of an AST representing
     the contents.  This AST can then be turned into a code object by
     ‘PyAST_Compile()’.  For more information, read the source code, and
     then ask questions on python-dev.

     The AST code was developed under Jeremy Hylton’s management, and
     implemented by (in alphabetical order) Brett Cannon, Nick Coghlan,
     Grant Edwards, John Ehresman, Kurt Kaiser, Neal Norwitz, Tim
     Peters, Armin Rigo, and Neil Schemenauer, plus the participants in
     a number of AST sprints at conferences such as PyCon.

   * Evan Jones’s patch to obmalloc, first described in a talk at PyCon
     DC 2005, was applied.  Python 2.4 allocated small objects in
     256K-sized arenas, but never freed arenas.  With this patch, Python
     will free arenas when they’re empty.  The net effect is that on
     some platforms, when you allocate many objects, Python’s memory
     usage may actually drop when you delete them and the memory may be
     returned to the operating system.  (Implemented by Evan Jones, and
     reworked by Tim Peters.)

     Note that this change means extension modules must be more careful
     when allocating memory.  Python’s API has many different functions
     for allocating memory that are grouped into families.  For example,
     *note PyMem_Malloc(): c87, *note PyMem_Realloc(): 106f, and *note
     PyMem_Free(): 1491. are one family that allocates raw memory, while
     *note PyObject_Malloc(): c89, *note PyObject_Realloc(): 1492, and
     *note PyObject_Free(): c86. are another family that’s supposed to
     be used for creating Python objects.

     Previously these different families all reduced to the platform’s
     ‘malloc()’ and ‘free()’ functions.  This meant it didn’t matter if
     you got things wrong and allocated memory with the ‘PyMem’ function
     but freed it with the ‘PyObject’ function.  With 2.5’s changes to
     obmalloc, these families now do different things and mismatches
     will probably result in a segfault.  You should carefully test your
     C extension modules with Python 2.5.

   * The built-in set types now have an official C API. Call *note
     PySet_New(): 1493. and *note PyFrozenSet_New(): 1494. to create a
     new set, *note PySet_Add(): 1495. and *note PySet_Discard(): 1496.
     to add and remove elements, and *note PySet_Contains(): 1497. and
     *note PySet_Size(): 1498. to examine the set’s state.  (Contributed
     by Raymond Hettinger.)

   * C code can now obtain information about the exact revision of the
     Python interpreter by calling the *note Py_GetBuildInfo(): 1480.
     function that returns a string of build information like this:
     ‘"trunk:45355:45356M, Apr 13 2006, 07:42:19"’.  (Contributed by
     Barry Warsaw.)

   * Two new macros can be used to indicate C functions that are local
     to the current file so that a faster calling convention can be
     used.  *note Py_LOCAL: 1499. declares the function as returning a
     value of the specified 'type' and uses a fast-calling qualifier.
     *note Py_LOCAL_INLINE: 149a. does the same thing and also requests
     the function be inlined.  If macro ‘PY_LOCAL_AGGRESSIVE’ is defined
     before ‘python.h’ is included, a set of more aggressive
     optimizations are enabled for the module; you should benchmark the
     results to find out if these optimizations actually make the code
     faster.  (Contributed by Fredrik Lundh at the NeedForSpeed sprint.)

   * ‘PyErr_NewException(name, base, dict)’ can now accept a tuple of
     base classes as its 'base' argument.  (Contributed by Georg
     Brandl.)

   * The ‘PyErr_Warn()’ function for issuing warnings is now deprecated
     in favour of ‘PyErr_WarnEx(category, message, stacklevel)’ which
     lets you specify the number of stack frames separating this
     function and the caller.  A 'stacklevel' of 1 is the function
     calling *note PyErr_WarnEx(): 149b, 2 is the function above that,
     and so forth.  (Added by Neal Norwitz.)

   * The CPython interpreter is still written in C, but the code can now
     be compiled with a C++ compiler without errors.  (Implemented by
     Anthony Baxter, Martin von Löwis, Skip Montanaro.)

   * The ‘PyRange_New()’ function was removed.  It was never documented,
     never used in the core code, and had dangerously lax error
     checking.  In the unlikely case that your extensions were using it,
     you can replace it by something like the following:

          range = PyObject_CallFunction((PyObject*) &PyRange_Type, "lll",
                                        start, stop, step);

* Menu:

* Port-Specific Changes::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0347/

   (2) https://peps.python.org/pep-0353/

   (3) https://peps.python.org/pep-0339/


File: python.info,  Node: Port-Specific Changes,  Up: Build and C API Changes<10>

1.17.14.1 Port-Specific Changes
...............................

   * MacOS X (10.3 and higher): dynamic loading of modules now uses the
     ‘dlopen()’ function instead of MacOS-specific functions.

   * MacOS X: an ‘--enable-universalsdk’ switch was added to the
     ‘configure’ script that compiles the interpreter as a universal
     binary able to run on both PowerPC and Intel processors.
     (Contributed by Ronald Oussoren; bpo-2573(1).)

   * Windows: ‘.dll’ is no longer supported as a filename extension for
     extension modules.  ‘.pyd’ is now the only filename extension that
     will be searched for.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=2573


File: python.info,  Node: Porting to Python 2 5,  Next: Acknowledgements<3>,  Prev: Build and C API Changes<10>,  Up: What’s New in Python 2 5

1.17.15 Porting to Python 2.5
-----------------------------

This section lists previously described changes that may require changes
to your code:

   * ASCII is now the default encoding for modules.  It’s now a syntax
     error if a module contains string literals with 8-bit characters
     but doesn’t have an encoding declaration.  In Python 2.4 this
     triggered a warning, not a syntax error.

   * Previously, the ‘gi_frame’ attribute of a generator was always a
     frame object.  Because of the PEP 342(1) changes described in
     section *note PEP 342; New Generator Features: 1452, it’s now
     possible for ‘gi_frame’ to be ‘None’.

   * A new warning, *note UnicodeWarning: 1472, is triggered when you
     attempt to compare a Unicode string and an 8-bit string that can’t
     be converted to Unicode using the default ASCII encoding.
     Previously such comparisons would raise a *note UnicodeDecodeError:
     a20. exception.

   * Library: the *note csv: 29. module is now stricter about multi-line
     quoted fields.  If your files contain newlines embedded within
     fields, the input should be split into lines in a manner which
     preserves the newline characters.

   * Library: the *note locale: 86. module’s *note format(): 622.
     function’s would previously accept any string as long as no more
     than one %char specifier appeared.  In Python 2.5, the argument
     must be exactly one %char specifier with no surrounding text.

   * Library: The *note pickle: a6. and ‘cPickle’ modules no longer
     accept a return value of ‘None’ from the *note __reduce__(): 9de.
     method; the method must return a tuple of arguments instead.  The
     modules also no longer accept the deprecated 'bin' keyword
     parameter.

   * Library: The *note SimpleXMLRPCServer: 12f. and ‘DocXMLRPCServer’
     classes now have a ‘rpc_paths’ attribute that constrains XML-RPC
     operations to a limited set of URL paths; the default is to allow
     only ‘'/'’ and ‘'/RPC2'’.  Setting ‘rpc_paths’ to ‘None’ or an
     empty tuple disables this path checking.

   * C API: Many functions now use *note Py_ssize_t: a6e. instead of int
     to allow processing more data on 64-bit machines.  Extension code
     may need to make the same change to avoid warnings and to support
     64-bit machines.  See the earlier section *note PEP 353; Using
     ssize_t as the index type: 1466. for a discussion of this change.

   * C API: The obmalloc changes mean that you must be careful to not
     mix usage of the ‘PyMem_*’ and ‘PyObject_*’ families of functions.
     Memory allocated with one family’s ‘*_Malloc’ must be freed with
     the corresponding family’s ‘*_Free’ function.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0342/


File: python.info,  Node: Acknowledgements<3>,  Prev: Porting to Python 2 5,  Up: What’s New in Python 2 5

1.17.16 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Georg Brandl, Nick Coghlan, Phillip J. Eby, Lars Gustäbel,
Raymond Hettinger, Ralf W. Grosse-Kunstleve, Kent Johnson, Iain Lowe,
Martin von Löwis, Fredrik Lundh, Andrew McNamara, Skip Montanaro,
Gustavo Niemeyer, Paul Prescod, James Pryor, Mike Rovner, Scott Weikart,
Barry Warsaw, Thomas Wouters.


File: python.info,  Node: What’s New in Python 2 4,  Next: What’s New in Python 2 3,  Prev: What’s New in Python 2 5,  Up: What’s New in Python

1.18 What’s New in Python 2.4
=============================


Author: A.M. Kuchling

This article explains the new features in Python 2.4.1, released on
March 30, 2005.

Python 2.4 is a medium-sized release.  It doesn’t introduce as many
changes as the radical Python 2.2, but introduces more features than the
conservative 2.3 release.  The most significant new language features
are function decorators and generator expressions; most other changes
are to the standard library.

According to the CVS change logs, there were 481 patches applied and 502
bugs fixed between Python 2.3 and 2.4.  Both figures are likely to be
underestimates.

This article doesn’t attempt to provide a complete specification of
every single new feature, but instead provides a brief introduction to
each feature.  For full details, you should refer to the documentation
for Python 2.4, such as the Python Library Reference and the Python
Reference Manual.  Often you will be referred to the PEP for a
particular new feature for explanations of the implementation and design
rationale.

* Menu:

* PEP 218; Built-In Set Objects: PEP 218 Built-In Set Objects.
* PEP 237; Unifying Long Integers and Integers: PEP 237 Unifying Long Integers and Integers.
* PEP 289; Generator Expressions: PEP 289 Generator Expressions.
* PEP 292; Simpler String Substitutions: PEP 292 Simpler String Substitutions.
* PEP 318; Decorators for Functions and Methods: PEP 318 Decorators for Functions and Methods.
* PEP 322; Reverse Iteration: PEP 322 Reverse Iteration.
* PEP 324; New subprocess Module: PEP 324 New subprocess Module.
* PEP 327; Decimal Data Type: PEP 327 Decimal Data Type.
* PEP 328; Multi-line Imports: PEP 328 Multi-line Imports.
* PEP 331; Locale-Independent Float/String Conversions: PEP 331 Locale-Independent Float/String Conversions.
* Other Language Changes: Other Language Changes<17>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<3>.
* Build and C API Changes: Build and C API Changes<11>.
* Porting to Python 2.4: Porting to Python 2 4.
* Acknowledgements: Acknowledgements<4>.


File: python.info,  Node: PEP 218 Built-In Set Objects,  Next: PEP 237 Unifying Long Integers and Integers,  Up: What’s New in Python 2 4

1.18.1 PEP 218: Built-In Set Objects
------------------------------------

Python 2.3 introduced the ‘sets’ module.  C implementations of set data
types have now been added to the Python core as two new built-in types,
‘set(iterable)’ and ‘frozenset(iterable)’.  They provide high speed
operations for membership testing, for eliminating duplicates from
sequences, and for mathematical operations like unions, intersections,
differences, and symmetric differences.

     >>> a = set('abracadabra')              # form a set from a string
     >>> 'z' in a                            # fast membership testing
     False
     >>> a                                   # unique letters in a
     set(['a', 'r', 'b', 'c', 'd'])
     >>> ''.join(a)                          # convert back into a string
     'arbcd'

     >>> b = set('alacazam')                 # form a second set
     >>> a - b                               # letters in a but not in b
     set(['r', 'd', 'b'])
     >>> a | b                               # letters in either a or b
     set(['a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'])
     >>> a & b                               # letters in both a and b
     set(['a', 'c'])
     >>> a ^ b                               # letters in a or b but not both
     set(['r', 'd', 'b', 'm', 'z', 'l'])

     >>> a.add('z')                          # add a new element
     >>> a.update('wxy')                     # add multiple new elements
     >>> a
     set(['a', 'c', 'b', 'd', 'r', 'w', 'y', 'x', 'z'])
     >>> a.remove('x')                       # take one element out
     >>> a
     set(['a', 'c', 'b', 'd', 'r', 'w', 'y', 'z'])

The *note frozenset(): 5dd. type is an immutable version of *note set():
5dc.  Since it is immutable and hashable, it may be used as a dictionary
key or as a member of another set.

The ‘sets’ module remains in the standard library, and may be useful if
you wish to subclass the ‘Set’ or ‘ImmutableSet’ classes.  There are
currently no plans to deprecate the module.

See also
........

PEP 218(1) - Adding a Built-In Set Object Type

     Originally proposed by Greg Wilson and ultimately implemented by
     Raymond Hettinger.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0218/


File: python.info,  Node: PEP 237 Unifying Long Integers and Integers,  Next: PEP 289 Generator Expressions,  Prev: PEP 218 Built-In Set Objects,  Up: What’s New in Python 2 4

1.18.2 PEP 237: Unifying Long Integers and Integers
---------------------------------------------------

The lengthy transition process for this PEP, begun in Python 2.2, takes
another step forward in Python 2.4.  In 2.3, certain integer operations
that would behave differently after int/long unification triggered *note
FutureWarning: 418. warnings and returned values limited to 32 or 64
bits (depending on your platform).  In 2.4, these expressions no longer
produce a warning and instead produce a different result that’s usually
a long integer.

The problematic expressions are primarily left shifts and lengthy
hexadecimal and octal constants.  For example, ‘2 << 32’ results in a
warning in 2.3, evaluating to 0 on 32-bit platforms.  In Python 2.4,
this expression now returns the correct answer, 8589934592.

See also
........

PEP 237(1) - Unifying Long Integers and Integers

     Original PEP written by Moshe Zadka and GvR. The changes for 2.4
     were implemented by Kalle Svensson.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0237/


File: python.info,  Node: PEP 289 Generator Expressions,  Next: PEP 292 Simpler String Substitutions,  Prev: PEP 237 Unifying Long Integers and Integers,  Up: What’s New in Python 2 4

1.18.3 PEP 289: Generator Expressions
-------------------------------------

The iterator feature introduced in Python 2.2 and the *note itertools:
81. module make it easier to write programs that loop through large data
sets without having the entire data set in memory at one time.  List
comprehensions don’t fit into this picture very well because they
produce a Python list object containing all of the items.  This
unavoidably pulls all of the objects into memory, which can be a problem
if your data set is very large.  When trying to write a functionally
styled program, it would be natural to write something like:

     links = [link for link in get_all_links() if not link.followed]
     for link in links:
         ...

instead of

     for link in get_all_links():
         if link.followed:
             continue
         ...

The first form is more concise and perhaps more readable, but if you’re
dealing with a large number of link objects you’d have to write the
second form to avoid having all link objects in memory at the same time.

Generator expressions work similarly to list comprehensions but don’t
materialize the entire list; instead they create a generator that will
return elements one by one.  The above example could be written as:

     links = (link for link in get_all_links() if not link.followed)
     for link in links:
         ...

Generator expressions always have to be written inside parentheses, as
in the above example.  The parentheses signalling a function call also
count, so if you want to create an iterator that will be immediately
passed to a function you could write:

     print sum(obj.count for obj in list_all_objects())

Generator expressions differ from list comprehensions in various small
ways.  Most notably, the loop variable ('obj' in the above example) is
not accessible outside of the generator expression.  List comprehensions
leave the variable assigned to its last value; future versions of Python
will change this, making list comprehensions match generator expressions
in this respect.

See also
........

PEP 289(1) - Generator Expressions

     Proposed by Raymond Hettinger and implemented by Jiwon Seo with
     early efforts steered by Hye-Shik Chang.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0289/


File: python.info,  Node: PEP 292 Simpler String Substitutions,  Next: PEP 318 Decorators for Functions and Methods,  Prev: PEP 289 Generator Expressions,  Up: What’s New in Python 2 4

1.18.4 PEP 292: Simpler String Substitutions
--------------------------------------------

Some new classes in the standard library provide an alternative
mechanism for substituting variables into strings; this style of
substitution may be better for applications where untrained users need
to edit templates.

The usual way of substituting variables by name is the ‘%’ operator:

     >>> '%(page)i: %(title)s' % {'page':2, 'title': 'The Best of Times'}
     '2: The Best of Times'

When writing the template string, it can be easy to forget the ‘i’ or
‘s’ after the closing parenthesis.  This isn’t a big problem if the
template is in a Python module, because you run the code, get an
“Unsupported format character” *note ValueError: 202, and fix the
problem.  However, consider an application such as Mailman where
template strings or translations are being edited by users who aren’t
aware of the Python language.  The format string’s syntax is complicated
to explain to such users, and if they make a mistake, it’s difficult to
provide helpful feedback to them.

PEP 292 adds a ‘Template’ class to the *note string: d3. module that
uses ‘$’ to indicate a substitution:

     >>> import string
     >>> t = string.Template('$page: $title')
     >>> t.substitute({'page':2, 'title': 'The Best of Times'})
     '2: The Best of Times'

If a key is missing from the dictionary, the ‘substitute()’ method will
raise a *note KeyError: 345.  There’s also a ‘safe_substitute()’ method
that ignores missing keys:

     >>> t = string.Template('$page: $title')
     >>> t.safe_substitute({'page':3})
     '3: $title'

See also
........

PEP 292(1) - Simpler String Substitutions

     Written and implemented by Barry Warsaw.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0292/


File: python.info,  Node: PEP 318 Decorators for Functions and Methods,  Next: PEP 322 Reverse Iteration,  Prev: PEP 292 Simpler String Substitutions,  Up: What’s New in Python 2 4

1.18.5 PEP 318: Decorators for Functions and Methods
----------------------------------------------------

Python 2.2 extended Python’s object model by adding static methods and
class methods, but it didn’t extend Python’s syntax to provide any new
way of defining static or class methods.  Instead, you had to write a
*note def: 14a9. statement in the usual way, and pass the resulting
method to a *note staticmethod(): 419. or *note classmethod(): 166.
function that would wrap up the function as a method of the new type.
Your code would look like this:

     class C:
        def meth (cls):
            ...

        meth = classmethod(meth)   # Rebind name to wrapped-up class method

If the method was very long, it would be easy to miss or forget the
*note classmethod(): 166. invocation after the function body.

The intention was always to add some syntax to make such definitions
more readable, but at the time of 2.2’s release a good syntax was not
obvious.  Today a good syntax 'still' isn’t obvious but users are asking
for easier access to the feature; a new syntactic feature has been added
to meet this need.

The new feature is called “function decorators”.  The name comes from
the idea that *note classmethod(): 166, *note staticmethod(): 419, and
friends are storing additional information on a function object; they’re
'decorating' functions with more details.

The notation borrows from Java and uses the ‘'@'’ character as an
indicator.  Using the new syntax, the example above would be written:

     class C:

        @classmethod
        def meth (cls):
            ...

The ‘@classmethod’ is shorthand for the ‘meth=classmethod(meth)’
assignment.  More generally, if you have the following:

     @A
     @B
     @C
     def f ():
         ...

It’s equivalent to the following pre-decorator code:

     def f(): ...
     f = A(B(C(f)))

Decorators must come on the line before a function definition, one
decorator per line, and can’t be on the same line as the def statement,
meaning that ‘@A def f(): ...’ is illegal.  You can only decorate
function definitions, either at the module level or inside a class; you
can’t decorate class definitions.

A decorator is just a function that takes the function to be decorated
as an argument and returns either the same function or some new object.
The return value of the decorator need not be callable (though it
typically is), unless further decorators will be applied to the result.
It’s easy to write your own decorators.  The following simple example
just sets an attribute on the function object:

     >>> def deco(func):
     ...    func.attr = 'decorated'
     ...    return func
     ...
     >>> @deco
     ... def f(): pass
     ...
     >>> f
     <function f at 0x402ef0d4>
     >>> f.attr
     'decorated'
     >>>

As a slightly more realistic example, the following decorator checks
that the supplied argument is an integer:

     def require_int (func):
         def wrapper (arg):
             assert isinstance(arg, int)
             return func(arg)

         return wrapper

     @require_int
     def p1 (arg):
         print arg

     @require_int
     def p2(arg):
         print arg*2

An example in PEP 318(1) contains a fancier version of this idea that
lets you both specify the required type and check the returned type.

Decorator functions can take arguments.  If arguments are supplied, your
decorator function is called with only those arguments and must return a
new decorator function; this function must take a single function and
return a function, as previously described.  In other words, ‘@A @B
@C(args)’ becomes:

     def f(): ...
     _deco = C(args)
     f = A(B(_deco(f)))

Getting this right can be slightly brain-bending, but it’s not too
difficult.

A small related change makes the *note func_name: 131c. attribute of
functions writable.  This attribute is used to display function names in
tracebacks, so decorators should change the name of any new function
that’s constructed and returned.

See also
........

PEP 318(2) - Decorators for Functions, Methods and Classes

     Written by Kevin D. Smith, Jim Jewett, and Skip Montanaro.  Several
     people wrote patches implementing function decorators, but the one
     that was actually checked in was patch #979728, written by Mark
     Russell.

‘https://wiki.python.org/moin/PythonDecoratorLibrary’

     This Wiki page contains several examples of decorators.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0318/

   (2) https://peps.python.org/pep-0318/


File: python.info,  Node: PEP 322 Reverse Iteration,  Next: PEP 324 New subprocess Module,  Prev: PEP 318 Decorators for Functions and Methods,  Up: What’s New in Python 2 4

1.18.6 PEP 322: Reverse Iteration
---------------------------------

A new built-in function, ‘reversed(seq)’, takes a sequence and returns
an iterator that loops over the elements of the sequence in reverse
order.

     >>> for i in reversed(xrange(1,4)):
     ...    print i
     ...
     3
     2
     1

Compared to extended slicing, such as ‘range(1,4)[::-1]’, *note
reversed(): 86c. is easier to read, runs faster, and uses substantially
less memory.

Note that *note reversed(): 86c. only accepts sequences, not arbitrary
iterators.  If you want to reverse an iterator, first convert it to a
list with *note list(): 614.

     >>> input = open('/etc/passwd', 'r')
     >>> for line in reversed(list(input)):
     ...   print line
     ...
     root:*:0:0:System Administrator:/var/root:/bin/tcsh
       ...

See also
........

PEP 322(1) - Reverse Iteration

     Written and implemented by Raymond Hettinger.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0322/


File: python.info,  Node: PEP 324 New subprocess Module,  Next: PEP 327 Decimal Data Type,  Prev: PEP 322 Reverse Iteration,  Up: What’s New in Python 2 4

1.18.7 PEP 324: New subprocess Module
-------------------------------------

The standard library provides a number of ways to execute a subprocess,
offering different features and different levels of complexity.
‘os.system(command)’ is easy to use, but slow (it runs a shell process
which executes the command) and dangerous (you have to be careful about
escaping the shell’s metacharacters).  The ‘popen2’ module offers
classes that can capture standard output and standard error from the
subprocess, but the naming is confusing.  The *note subprocess: d6.
module cleans this up, providing a unified interface that offers all the
features you might need.

Instead of ‘popen2’’s collection of classes, *note subprocess: d6.
contains a single class called *note subprocess.Popen: 199. whose
constructor supports a number of different keyword arguments.

     class Popen(args, bufsize=0, executable=None,
                 stdin=None, stdout=None, stderr=None,
                 preexec_fn=None, close_fds=False, shell=False,
                 cwd=None, env=None, universal_newlines=False,
                 startupinfo=None, creationflags=0):

'args' is commonly a sequence of strings that will be the arguments to
the program executed as the subprocess.  (If the 'shell' argument is
true, 'args' can be a string which will then be passed on to the shell
for interpretation, just as *note os.system(): 14ac. does.)

'stdin', 'stdout', and 'stderr' specify what the subprocess’s input,
output, and error streams will be.  You can provide a file object or a
file descriptor, or you can use the constant ‘subprocess.PIPE’ to create
a pipe between the subprocess and the parent.

The constructor has a number of handy options:

   * 'close_fds' requests that all file descriptors be closed before
     running the subprocess.

   * 'cwd' specifies the working directory in which the subprocess will
     be executed (defaulting to whatever the parent’s working directory
     is).

   * 'env' is a dictionary specifying environment variables.

   * 'preexec_fn' is a function that gets called before the child is
     started.

   * 'universal_newlines' opens the child’s input and output using
     Python’s *note universal newlines: d62. feature.

Once you’ve created the ‘Popen’ instance, you can call its ‘wait()’
method to pause until the subprocess has exited, ‘poll()’ to check if
it’s exited without pausing, or ‘communicate(data)’ to send the string
'data' to the subprocess’s standard input.  ‘communicate(data)’ then
reads any data that the subprocess has sent to its standard output or
standard error, returning a tuple ‘(stdout_data, stderr_data)’.

‘call()’ is a shortcut that passes its arguments along to the ‘Popen’
constructor, waits for the command to complete, and returns the status
code of the subprocess.  It can serve as a safer analog to *note
os.system(): 14ac.:

     sts = subprocess.call(['dpkg', '-i', '/tmp/new-package.deb'])
     if sts == 0:
         # Success
         ...
     else:
         # dpkg returned an error
         ...

The command is invoked without use of the shell.  If you really do want
to use the shell, you can add ‘shell=True’ as a keyword argument and
provide a string instead of a sequence:

     sts = subprocess.call('dpkg -i /tmp/new-package.deb', shell=True)

The PEP takes various examples of shell and Python code and shows how
they’d be translated into Python code that uses *note subprocess: d6.
Reading this section of the PEP is highly recommended.

See also
........

PEP 324(1) - subprocess - New process module

     Written and implemented by Peter Åstrand, with assistance from
     Fredrik Lundh and others.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0324/


File: python.info,  Node: PEP 327 Decimal Data Type,  Next: PEP 328 Multi-line Imports,  Prev: PEP 324 New subprocess Module,  Up: What’s New in Python 2 4

1.18.8 PEP 327: Decimal Data Type
---------------------------------

Python has always supported floating-point (FP) numbers, based on the
underlying C double type, as a data type.  However, while most
programming languages provide a floating-point type, many people (even
programmers) are unaware that floating-point numbers don’t represent
certain decimal fractions accurately.  The new ‘Decimal’ type can
represent these fractions accurately, up to a user-specified precision
limit.

* Menu:

* Why is Decimal needed?::
* The Decimal type::
* The Context type::


File: python.info,  Node: Why is Decimal needed?,  Next: The Decimal type,  Up: PEP 327 Decimal Data Type

1.18.8.1 Why is Decimal needed?
...............................

The limitations arise from the representation used for floating-point
numbers.  FP numbers are made up of three components:

   * The sign, which is positive or negative.

   * The mantissa, which is a single-digit binary number followed by a
     fractional part.  For example, ‘1.01’ in base-2 notation is ‘1 +
     0/2 + 1/4’, or 1.25 in decimal notation.

   * The exponent, which tells where the decimal point is located in the
     number represented.

For example, the number 1.25 has positive sign, a mantissa value of 1.01
(in binary), and an exponent of 0 (the decimal point doesn’t need to be
shifted).  The number 5 has the same sign and mantissa, but the exponent
is 2 because the mantissa is multiplied by 4 (2 to the power of the
exponent 2); 1.25 * 4 equals 5.

Modern systems usually provide floating-point support that conforms to a
standard called IEEE 754.  C’s double type is usually implemented as a
64-bit IEEE 754 number, which uses 52 bits of space for the mantissa.
This means that numbers can only be specified to 52 bits of precision.
If you’re trying to represent numbers whose expansion repeats endlessly,
the expansion is cut off after 52 bits.  Unfortunately, most software
needs to produce output in base 10, and common fractions in base 10 are
often repeating decimals in binary.  For example, 1.1 decimal is binary
‘1.0001100110011 ...’; .1 = 1/16 + 1/32 + 1/256 plus an infinite number
of additional terms.  IEEE 754 has to chop off that infinitely repeated
decimal after 52 digits, so the representation is slightly inaccurate.

Sometimes you can see this inaccuracy when the number is printed:

     >>> 1.1
     1.1000000000000001

The inaccuracy isn’t always visible when you print the number because
the FP-to-decimal-string conversion is provided by the C library, and
most C libraries try to produce sensible output.  Even if it’s not
displayed, however, the inaccuracy is still there and subsequent
operations can magnify the error.

For many applications this doesn’t matter.  If I’m plotting points and
displaying them on my monitor, the difference between 1.1 and
1.1000000000000001 is too small to be visible.  Reports often limit
output to a certain number of decimal places, and if you round the
number to two or three or even eight decimal places, the error is never
apparent.  However, for applications where it does matter, it’s a lot of
work to implement your own custom arithmetic routines.

Hence, the ‘Decimal’ type was created.


File: python.info,  Node: The Decimal type,  Next: The Context type,  Prev: Why is Decimal needed?,  Up: PEP 327 Decimal Data Type

1.18.8.2 The ‘Decimal’ type
...........................

A new module, *note decimal: 36, was added to Python’s standard library.
It contains two classes, ‘Decimal’ and ‘Context’.  ‘Decimal’ instances
represent numbers, and ‘Context’ instances are used to wrap up various
settings such as the precision and default rounding mode.

‘Decimal’ instances are immutable, like regular Python integers and FP
numbers; once it’s been created, you can’t change the value an instance
represents.  ‘Decimal’ instances can be created from integers or
strings:

     >>> import decimal
     >>> decimal.Decimal(1972)
     Decimal("1972")
     >>> decimal.Decimal("1.1")
     Decimal("1.1")

You can also provide tuples containing the sign, the mantissa
represented as a tuple of decimal digits, and the exponent:

     >>> decimal.Decimal((1, (1, 4, 7, 5), -2))
     Decimal("-14.75")

Cautionary note: the sign bit is a Boolean value, so 0 is positive and 1
is negative.

Converting from floating-point numbers poses a bit of a problem: should
the FP number representing 1.1 turn into the decimal number for exactly
1.1, or for 1.1 plus whatever inaccuracies are introduced?  The decision
was to dodge the issue and leave such a conversion out of the API.
Instead, you should convert the floating-point number into a string
using the desired precision and pass the string to the ‘Decimal’
constructor:

     >>> f = 1.1
     >>> decimal.Decimal(str(f))
     Decimal("1.1")
     >>> decimal.Decimal('%.12f' % f)
     Decimal("1.100000000000")

Once you have ‘Decimal’ instances, you can perform the usual
mathematical operations on them.  One limitation: exponentiation
requires an integer exponent:

     >>> a = decimal.Decimal('35.72')
     >>> b = decimal.Decimal('1.73')
     >>> a+b
     Decimal("37.45")
     >>> a-b
     Decimal("33.99")
     >>> a*b
     Decimal("61.7956")
     >>> a/b
     Decimal("20.64739884393063583815028902")
     >>> a ** 2
     Decimal("1275.9184")
     >>> a**b
     Traceback (most recent call last):
       ...
     decimal.InvalidOperation: x ** (non-integer)

You can combine ‘Decimal’ instances with integers, but not with
floating-point numbers:

     >>> a + 4
     Decimal("39.72")
     >>> a + 4.5
     Traceback (most recent call last):
       ...
     TypeError: You can interact Decimal only with int, long or Decimal data types.
     >>>

‘Decimal’ numbers can be used with the *note math: 8e. and *note cmath:
18. modules, but note that they’ll be immediately converted to
floating-point numbers before the operation is performed, resulting in a
possible loss of precision and accuracy.  You’ll also get back a regular
floating-point number and not a ‘Decimal’.

     >>> import math, cmath
     >>> d = decimal.Decimal('123456789012.345')
     >>> math.sqrt(d)
     351364.18288201344
     >>> cmath.sqrt(-d)
     351364.18288201344j

‘Decimal’ instances have a ‘sqrt()’ method that returns a ‘Decimal’, but
if you need other things such as trigonometric functions you’ll have to
implement them.

     >>> d.sqrt()
     Decimal("351364.1828820134592177245001")


File: python.info,  Node: The Context type,  Prev: The Decimal type,  Up: PEP 327 Decimal Data Type

1.18.8.3 The ‘Context’ type
...........................

Instances of the ‘Context’ class encapsulate several settings for
decimal operations:

   * ‘prec’ is the precision, the number of decimal places.

   * ‘rounding’ specifies the rounding mode.  The *note decimal: 36.
     module has constants for the various possibilities: ‘ROUND_DOWN’,
     ‘ROUND_CEILING’, ‘ROUND_HALF_EVEN’, and various others.

   * ‘traps’ is a dictionary specifying what happens on encountering
     certain error conditions: either an exception is raised or a value
     is returned.  Some examples of error conditions are division by
     zero, loss of precision, and overflow.

There’s a thread-local default context available by calling
‘getcontext()’; you can change the properties of this context to alter
the default precision, rounding, or trap handling.  The following
example shows the effect of changing the precision of the default
context:

     >>> decimal.getcontext().prec
     28
     >>> decimal.Decimal(1) / decimal.Decimal(7)
     Decimal("0.1428571428571428571428571429")
     >>> decimal.getcontext().prec = 9
     >>> decimal.Decimal(1) / decimal.Decimal(7)
     Decimal("0.142857143")

The default action for error conditions is selectable; the module can
either return a special value such as infinity or not-a-number, or
exceptions can be raised:

     >>> decimal.Decimal(1) / decimal.Decimal(0)
     Traceback (most recent call last):
       ...
     decimal.DivisionByZero: x / 0
     >>> decimal.getcontext().traps[decimal.DivisionByZero] = False
     >>> decimal.Decimal(1) / decimal.Decimal(0)
     Decimal("Infinity")
     >>>

The ‘Context’ instance also has various methods for formatting numbers
such as ‘to_eng_string()’ and ‘to_sci_string()’.

For more information, see the documentation for the *note decimal: 36.
module, which includes a quick-start tutorial and a reference.

See also
........

PEP 327(1) - Decimal Data Type

     Written by Facundo Batista and implemented by Facundo Batista, Eric
     Price, Raymond Hettinger, Aahz, and Tim Peters.

http://www.lahey.com/float.htm(2)

     The article uses Fortran code to illustrate many of the problems
     that floating-point inaccuracy can cause.

‘https://speleotrove.com/decimal/’

     A description of a decimal-based representation.  This
     representation is being proposed as a standard, and underlies the
     new Python decimal type.  Much of this material was written by Mike
     Cowlishaw, designer of the Rexx language.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0327/

   (2) 
https://web.archive.org/web/20230604072523/http://www.lahey.com/float.htm


File: python.info,  Node: PEP 328 Multi-line Imports,  Next: PEP 331 Locale-Independent Float/String Conversions,  Prev: PEP 327 Decimal Data Type,  Up: What’s New in Python 2 4

1.18.9 PEP 328: Multi-line Imports
----------------------------------

One language change is a small syntactic tweak aimed at making it easier
to import many names from a module.  In a ‘from module import names’
statement, 'names' is a sequence of names separated by commas.  If the
sequence is very long, you can either write multiple imports from the
same module, or you can use backslashes to escape the line endings like
this:

     from SimpleXMLRPCServer import SimpleXMLRPCServer,\
                 SimpleXMLRPCRequestHandler,\
                 CGIXMLRPCRequestHandler,\
                 resolve_dotted_attribute

The syntactic change in Python 2.4 simply allows putting the names
within parentheses.  Python ignores newlines within a parenthesized
expression, so the backslashes are no longer needed:

     from SimpleXMLRPCServer import (SimpleXMLRPCServer,
                                     SimpleXMLRPCRequestHandler,
                                     CGIXMLRPCRequestHandler,
                                     resolve_dotted_attribute)

The PEP also proposes that all *note import: 5e5. statements be absolute
imports, with a leading ‘.’ character to indicate a relative import.
This part of the PEP was not implemented for Python 2.4, but was
completed for Python 2.5.

See also
........

PEP 328(1) - Imports: Multi-Line and Absolute/Relative

     Written by Aahz.  Multi-line imports were implemented by Dima
     Dorfman.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0328/


File: python.info,  Node: PEP 331 Locale-Independent Float/String Conversions,  Next: Other Language Changes<17>,  Prev: PEP 328 Multi-line Imports,  Up: What’s New in Python 2 4

1.18.10 PEP 331: Locale-Independent Float/String Conversions
------------------------------------------------------------

The *note locale: 86. modules lets Python software select various
conversions and display conventions that are localized to a particular
country or language.  However, the module was careful to not change the
numeric locale because various functions in Python’s implementation
required that the numeric locale remain set to the ‘'C'’ locale.  Often
this was because the code was using the C library’s ‘atof()’ function.

Not setting the numeric locale caused trouble for extensions that used
third-party C libraries, however, because they wouldn’t have the correct
locale set.  The motivating example was GTK+, whose user interface
widgets weren’t displaying numbers in the current locale.

The solution described in the PEP is to add three new functions to the
Python API that perform ASCII-only conversions, ignoring the locale
setting:

   * ‘PyOS_ascii_strtod(str, ptr)’ and ‘PyOS_ascii_atof(str, ptr)’ both
     convert a string to a C double.

   * ‘PyOS_ascii_formatd(buffer, buf_len, format, d)’ converts a double
     to an ASCII string.

The code for these functions came from the GLib library
(https://developer-old.gnome.org/glib/2.26/(1)), whose developers kindly
relicensed the relevant functions and donated them to the Python
Software Foundation.  The *note locale: 86. module can now change the
numeric locale, letting extensions such as GTK+ produce the correct
results.

See also
........

PEP 331(2) - Locale-Independent Float/String Conversions

     Written by Christian R. Reis, and implemented by Gustavo Carneiro.

   ---------- Footnotes ----------

   (1) 
http://web.archive.org/web/20210306104320/https://developer.gnome.org/glib/2.26/

   (2) https://peps.python.org/pep-0331/


File: python.info,  Node: Other Language Changes<17>,  Next: New Improved and Deprecated Modules<3>,  Prev: PEP 331 Locale-Independent Float/String Conversions,  Up: What’s New in Python 2 4

1.18.11 Other Language Changes
------------------------------

Here are all of the changes that Python 2.4 makes to the core Python
language.

   * Decorators for functions and methods were added ( PEP 318(1)).

   * Built-in *note set(): 5dc. and *note frozenset(): 5dd. types were
     added ( PEP 218(2)).  Other new built-ins include the
     ‘reversed(seq)’ function ( PEP 322(3)).

   * Generator expressions were added ( PEP 289(4)).

   * Certain numeric expressions no longer return values restricted to
     32 or 64 bits ( PEP 237(5)).

   * You can now put parentheses around the list of names in a ‘from
     module import names’ statement ( PEP 328(6)).

   * The *note dict.update(): 14b4. method now accepts the same argument
     forms as the *note dict: 256. constructor.  This includes any
     mapping, any iterable of key/value pairs, and keyword arguments.
     (Contributed by Raymond Hettinger.)

   * The string methods ‘ljust()’, ‘rjust()’, and ‘center()’ now take an
     optional argument for specifying a fill character other than a
     space.  (Contributed by Raymond Hettinger.)

   * Strings also gained an ‘rsplit()’ method that works like the
     ‘split()’ method but splits from the end of the string.
     (Contributed by Sean Reifschneider.)

          >>> 'www.python.org'.split('.', 1)
          ['www', 'python.org']
          'www.python.org'.rsplit('.', 1)
          ['www.python', 'org']

   * Three keyword parameters, 'cmp', 'key', and 'reverse', were added
     to the ‘sort()’ method of lists.  These parameters make some common
     usages of ‘sort()’ simpler.  All of these parameters are optional.

     For the 'cmp' parameter, the value should be a comparison function
     that takes two parameters and returns -1, 0, or +1 depending on how
     the parameters compare.  This function will then be used to sort
     the list.  Previously this was the only parameter that could be
     provided to ‘sort()’.

     'key' should be a single-parameter function that takes a list
     element and returns a comparison key for the element.  The list is
     then sorted using the comparison keys.  The following example sorts
     a list case-insensitively:

          >>> L = ['A', 'b', 'c', 'D']
          >>> L.sort()                 # Case-sensitive sort
          >>> L
          ['A', 'D', 'b', 'c']
          >>> # Using 'key' parameter to sort list
          >>> L.sort(key=lambda x: x.lower())
          >>> L
          ['A', 'b', 'c', 'D']
          >>> # Old-fashioned way
          >>> L.sort(cmp=lambda x,y: cmp(x.lower(), y.lower()))
          >>> L
          ['A', 'b', 'c', 'D']

     The last example, which uses the 'cmp' parameter, is the old way to
     perform a case-insensitive sort.  It works but is slower than using
     a 'key' parameter.  Using 'key' calls ‘lower()’ method once for
     each element in the list while using 'cmp' will call it twice for
     each comparison, so using 'key' saves on invocations of the
     ‘lower()’ method.

     For simple key functions and comparison functions, it is often
     possible to avoid a *note lambda: 12e4. expression by using an
     unbound method instead.  For example, the above case-insensitive
     sort is best written as:

          >>> L.sort(key=str.lower)
          >>> L
          ['A', 'b', 'c', 'D']

     Finally, the 'reverse' parameter takes a Boolean value.  If the
     value is true, the list will be sorted into reverse order.  Instead
     of ‘L.sort(); L.reverse()’, you can now write
     ‘L.sort(reverse=True)’.

     The results of sorting are now guaranteed to be stable.  This means
     that two entries with equal keys will be returned in the same order
     as they were input.  For example, you can sort a list of people by
     name, and then sort the list by age, resulting in a list sorted by
     age where people with the same age are in name-sorted order.

     (All changes to ‘sort()’ contributed by Raymond Hettinger.)

   * There is a new built-in function ‘sorted(iterable)’ that works like
     the in-place *note list.sort(): bee. method but can be used in
     expressions.  The differences are:

   * the input may be any iterable;

   * a newly formed copy is sorted, leaving the original intact; and

   * the expression returns the new sorted copy

          >>> L = [9,7,8,3,2,4,1,6,5]
          >>> [10+i for i in sorted(L)]       # usable in a list comprehension
          [11, 12, 13, 14, 15, 16, 17, 18, 19]
          >>> L                               # original is left unchanged
          [9,7,8,3,2,4,1,6,5]
          >>> sorted('Monty Python')          # any iterable may be an input
          [' ', 'M', 'P', 'h', 'n', 'n', 'o', 'o', 't', 't', 'y', 'y']

          >>> # List the contents of a dict sorted by key values
          >>> colormap = dict(red=1, blue=2, green=3, black=4, yellow=5)
          >>> for k, v in sorted(colormap.iteritems()):
          ...     print k, v
          ...
          black 4
          blue 2
          green 3
          red 1
          yellow 5

     (Contributed by Raymond Hettinger.)

   * Integer operations will no longer trigger an ‘OverflowWarning’.
     The ‘OverflowWarning’ warning will disappear in Python 2.5.

   * The interpreter gained a new switch, *note -m: 5e4, that takes a
     name, searches for the corresponding module on ‘sys.path’, and runs
     the module as a script.  For example, you can now run the Python
     profiler with ‘python -m profile’.  (Contributed by Nick Coghlan.)

   * The ‘eval(expr, globals, locals)’ and ‘execfile(filename, globals,
     locals)’ functions and the ‘exec’ statement now accept any mapping
     type for the 'locals' parameter.  Previously this had to be a
     regular Python dictionary.  (Contributed by Raymond Hettinger.)

   * The *note zip(): 7d4. built-in function and ‘itertools.izip()’ now
     return an empty list if called with no arguments.  Previously they
     raised a *note TypeError: 2c3. exception.  This makes them more
     suitable for use with variable length argument lists:

          >>> def transpose(array):
          ...    return zip(*array)
          ...
          >>> transpose([(1,2,3), (4,5,6)])
          [(1, 4), (2, 5), (3, 6)]
          >>> transpose([])
          []

     (Contributed by Raymond Hettinger.)

   * Encountering a failure while importing a module no longer leaves a
     partially initialized module object in ‘sys.modules’.  The
     incomplete module object left behind would fool further imports of
     the same module into succeeding, leading to confusing errors.
     (Fixed by Tim Peters.)

   * *note None: 678. is now a constant; code that binds a new value to
     the name ‘None’ is now a syntax error.  (Contributed by Raymond
     Hettinger.)

* Menu:

* Optimizations: Optimizations<16>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0318/

   (2) https://peps.python.org/pep-0218/

   (3) https://peps.python.org/pep-0322/

   (4) https://peps.python.org/pep-0289/

   (5) https://peps.python.org/pep-0237/

   (6) https://peps.python.org/pep-0328/


File: python.info,  Node: Optimizations<16>,  Up: Other Language Changes<17>

1.18.11.1 Optimizations
.......................

   * The inner loops for list and tuple slicing were optimized and now
     run about one-third faster.  The inner loops for dictionaries were
     also optimized, resulting in performance boosts for ‘keys()’,
     ‘values()’, ‘items()’, ‘iterkeys()’, ‘itervalues()’, and
     ‘iteritems()’.  (Contributed by Raymond Hettinger.)

   * The machinery for growing and shrinking lists was optimized for
     speed and for space efficiency.  Appending and popping from lists
     now runs faster due to more efficient code paths and less frequent
     use of the underlying system ‘realloc()’.  List comprehensions also
     benefit.  *note list.extend(): 360. was also optimized and no
     longer converts its argument into a temporary list before extending
     the base list.  (Contributed by Raymond Hettinger.)

   * *note list(): 614, *note tuple(): 373, *note map(): 86a, *note
     filter(): 86b, and *note zip(): 7d4. now run several times faster
     with non-sequence arguments that supply a ‘__len__()’ method.
     (Contributed by Raymond Hettinger.)

   * The methods ‘list.__getitem__()’, ‘dict.__getitem__()’, and
     ‘dict.__contains__()’ are now implemented as ‘method_descriptor’
     objects rather than ‘wrapper_descriptor’ objects.  This form of
     access doubles their performance and makes them more suitable for
     use as arguments to functionals: ‘map(mydict.__getitem__,
     keylist)’.  (Contributed by Raymond Hettinger.)

   * Added a new opcode, ‘LIST_APPEND’, that simplifies the generated
     bytecode for list comprehensions and speeds them up by about a
     third.  (Contributed by Raymond Hettinger.)

   * The peephole bytecode optimizer has been improved to produce
     shorter, faster bytecode; remarkably, the resulting bytecode is
     more readable.  (Enhanced by Raymond Hettinger.)

   * String concatenations in statements of the form ‘s = s + "abc"’ and
     ‘s += "abc"’ are now performed more efficiently in certain
     circumstances.  This optimization won’t be present in other Python
     implementations such as Jython, so you shouldn’t rely on it; using
     the ‘join()’ method of strings is still recommended when you want
     to efficiently glue a large number of strings together.
     (Contributed by Armin Rigo.)

The net result of the 2.4 optimizations is that Python 2.4 runs the
pystone benchmark around 5% faster than Python 2.3 and 35% faster than
Python 2.2.  (pystone is not a particularly good benchmark, but it’s the
most commonly used measurement of Python’s performance.  Your own
applications may show greater or smaller benefits from Python 2.4.)


File: python.info,  Node: New Improved and Deprecated Modules<3>,  Next: Build and C API Changes<11>,  Prev: Other Language Changes<17>,  Up: What’s New in Python 2 4

1.18.12 New, Improved, and Deprecated Modules
---------------------------------------------

As usual, Python’s standard library received a number of enhancements
and bug fixes.  Here’s a partial list of the most notable changes,
sorted alphabetically by module name.  Consult the ‘Misc/NEWS’ file in
the source tree for a more complete list of changes, or look through the
CVS logs for all the details.

   * The ‘asyncore’ module’s ‘loop()’ function now has a 'count'
     parameter that lets you perform a limited number of passes through
     the polling loop.  The default is still to loop forever.

   * The *note base64: e. module now has more complete RFC 3548(1)
     support for Base64, Base32, and Base16 encoding and decoding,
     including optional case folding and optional alternative alphabets.
     (Contributed by Barry Warsaw.)

   * The *note bisect: 11. module now has an underlying C implementation
     for improved performance.  (Contributed by Dmitry Vasiliev.)

   * The CJKCodecs collections of East Asian codecs, maintained by
     Hye-Shik Chang, was integrated into 2.4.  The new encodings are:

   * Chinese (PRC): gb2312, gbk, gb18030, big5hkscs, hz

   * Chinese (ROC): big5, cp950

   * 
     Japanese: cp932, euc-jis-2004, euc-jp, euc-jisx0213, iso-2022-jp,

          iso-2022-jp-1, iso-2022-jp-2, iso-2022-jp-3, iso-2022-jp-ext,
          iso-2022-jp-2004, shift-jis, shift-jisx0213, shift-jis-2004

   * Korean: cp949, euc-kr, johab, iso-2022-kr

   * Some other new encodings were added: HP Roman8, ISO_8859-11,
     ISO_8859-16, PCTP-154, and TIS-620.

   * The UTF-8 and UTF-16 codecs now cope better with receiving partial
     input.  Previously the ‘StreamReader’ class would try to read more
     data, making it impossible to resume decoding from the stream.  The
     ‘read()’ method will now return as much data as it can and future
     calls will resume decoding where previous ones left off.
     (Implemented by Walter Dörwald.)

   * There is a new *note collections: 1d. module for various
     specialized collection datatypes.  Currently it contains just one
     type, ‘deque’, a double-ended queue that supports efficiently
     adding and removing elements from either end:

          >>> from collections import deque
          >>> d = deque('ghi')        # make a new deque with three items
          >>> d.append('j')           # add a new entry to the right side
          >>> d.appendleft('f')       # add a new entry to the left side
          >>> d                       # show the representation of the deque
          deque(['f', 'g', 'h', 'i', 'j'])
          >>> d.pop()                 # return and remove the rightmost item
          'j'
          >>> d.popleft()             # return and remove the leftmost item
          'f'
          >>> list(d)                 # list the contents of the deque
          ['g', 'h', 'i']
          >>> 'h' in d                # search the deque
          True

     Several modules, such as the ‘Queue’ and *note threading: ed.
     modules, now take advantage of *note collections.deque: 5df. for
     improved performance.  (Contributed by Raymond Hettinger.)

   * The *note ConfigParser: 22. classes have been enhanced slightly.
     The *note read(): 14b7. method now returns a list of the files that
     were successfully parsed, and the *note set(): 12b3. method raises
     *note TypeError: 2c3. if passed a 'value' argument that isn’t a
     string.  (Contributed by John Belmonte and David Goodger.)

   * The *note curses: 2b. module now supports the ncurses extension
     ‘use_default_colors()’.  On platforms where the terminal supports
     transparency, this makes it possible to use a transparent
     background.  (Contributed by Jörg Lehmann.)

   * The *note difflib: 37. module now includes an ‘HtmlDiff’ class that
     creates an HTML table showing a side by side comparison of two
     versions of a text.  (Contributed by Dan Gass.)

   * The *note email: 3b. package was updated to version 3.0, which
     dropped various deprecated APIs and removes support for Python
     versions earlier than 2.3.  The 3.0 version of the package uses a
     new incremental parser for MIME messages, available in the
     ‘email.FeedParser’ module.  The new parser doesn’t require reading
     the entire message into memory, and doesn’t raise exceptions if a
     message is malformed; instead it records any problems in the
     ‘defect’ attribute of the message.  (Developed by Anthony Baxter,
     Barry Warsaw, Thomas Wouters, and others.)

   * The *note heapq: 69. module has been converted to C. The resulting
     tenfold improvement in speed makes the module suitable for handling
     high volumes of data.  In addition, the module has two new
     functions ‘nlargest()’ and ‘nsmallest()’ that use heaps to find the
     N largest or smallest values in a dataset without the expense of a
     full sort.  (Contributed by Raymond Hettinger.)

   * The *note httplib: 6e. module now contains constants for HTTP
     status codes defined in various HTTP-related RFC documents.
     Constants have names such as ‘OK’, ‘CREATED’, ‘CONTINUE’, and
     ‘MOVED_PERMANENTLY’; use pydoc to get a full list.  (Contributed by
     Andrew Eland.)

   * The *note imaplib: 74. module now supports IMAP’s THREAD command
     (contributed by Yves Dionne) and new ‘deleteacl()’ and ‘myrights()’
     methods (contributed by Arnaud Mazin).

   * The *note itertools: 81. module gained a ‘groupby(iterable[,
     *func*])’ function.  'iterable' is something that can be iterated
     over to return a stream of elements, and the optional 'func'
     parameter is a function that takes an element and returns a key
     value; if omitted, the key is simply the element itself.
     ‘groupby()’ then groups the elements into subsequences which have
     matching values of the key, and returns a series of 2-tuples
     containing the key value and an iterator over the subsequence.

     Here’s an example to make this clearer.  The 'key' function simply
     returns whether a number is even or odd, so the result of
     ‘groupby()’ is to return consecutive runs of odd or even numbers.

          >>> import itertools
          >>> L = [2, 4, 6, 7, 8, 9, 11, 12, 14]
          >>> for key_val, it in itertools.groupby(L, lambda x: x % 2):
          ...    print key_val, list(it)
          ...
          0 [2, 4, 6]
          1 [7]
          0 [8]
          1 [9, 11]
          0 [12, 14]
          >>>

     ‘groupby()’ is typically used with sorted input.  The logic for
     ‘groupby()’ is similar to the Unix ‘uniq’ filter which makes it
     handy for eliminating, counting, or identifying duplicate elements:

          >>> word = 'abracadabra'
          >>> letters = sorted(word)   # Turn string into a sorted list of letters
          >>> letters
          ['a', 'a', 'a', 'a', 'a', 'b', 'b', 'c', 'd', 'r', 'r']
          >>> for k, g in itertools.groupby(letters):
          ...    print k, list(g)
          ...
          a ['a', 'a', 'a', 'a', 'a']
          b ['b', 'b']
          c ['c']
          d ['d']
          r ['r', 'r']
          >>> # List unique letters
          >>> [k for k, g in groupby(letters)]
          ['a', 'b', 'c', 'd', 'r']
          >>> # Count letter occurrences
          >>> [(k, len(list(g))) for k, g in groupby(letters)]
          [('a', 5), ('b', 2), ('c', 1), ('d', 1), ('r', 2)]

     (Contributed by Hye-Shik Chang.)

   * *note itertools: 81. also gained a function named ‘tee(iterator,
     N)’ that returns 'N' independent iterators that replicate
     'iterator'.  If 'N' is omitted, the default is 2.

          >>> L = [1,2,3]
          >>> i1, i2 = itertools.tee(L)
          >>> i1,i2
          (<itertools.tee object at 0x402c2080>, <itertools.tee object at 0x402c2090>)
          >>> list(i1)               # Run the first iterator to exhaustion
          [1, 2, 3]
          >>> list(i2)               # Run the second iterator to exhaustion
          [1, 2, 3]

     Note that ‘tee()’ has to keep copies of the values returned by the
     iterator; in the worst case, it may need to keep all of them.  This
     should therefore be used carefully if the leading iterator can run
     far ahead of the trailing iterator in a long stream of inputs.  If
     the separation is large, then you might as well use *note list():
     614. instead.  When the iterators track closely with one another,
     ‘tee()’ is ideal.  Possible applications include bookmarking,
     windowing, or lookahead iterators.  (Contributed by Raymond
     Hettinger.)

   * A number of functions were added to the *note locale: 86. module,
     such as ‘bind_textdomain_codeset()’ to specify a particular
     encoding and a family of ‘l*gettext()’ functions that return
     messages in the chosen encoding.  (Contributed by Gustavo
     Niemeyer.)

   * Some keyword arguments were added to the *note logging: 87.
     package’s ‘basicConfig()’ function to simplify log configuration.
     The default behavior is to log messages to standard error, but
     various keyword arguments can be specified to log to a particular
     file, change the logging format, or set the logging level.  For
     example:

          import logging
          logging.basicConfig(filename='/var/log/application.log',
              level=0,  # Log all messages
              format='%(levelname):%(process):%(thread):%(message)')

     Other additions to the *note logging: 87. package include a
     ‘log(level, msg)’ convenience method, as well as a
     ‘TimedRotatingFileHandler’ class that rotates its log files at a
     timed interval.  The module already had ‘RotatingFileHandler’,
     which rotated logs once the file exceeded a certain size.  Both
     classes derive from a new ‘BaseRotatingHandler’ class that can be
     used to implement other rotating handlers.

     (Changes implemented by Vinay Sajip.)

   * The *note marshal: 8d. module now shares interned strings on
     unpacking a data structure.  This may shrink the size of certain
     pickle strings, but the primary effect is to make ‘.pyc’ files
     significantly smaller.  (Contributed by Martin von Löwis.)

   * The ‘nntplib’ module’s ‘NNTP’ class gained ‘description()’ and
     ‘descriptions()’ methods to retrieve newsgroup descriptions for a
     single group or for a range of groups.  (Contributed by Jürgen A.
     Erhard.)

   * Two new functions were added to the *note operator: 9f. module,
     ‘attrgetter(attr)’ and ‘itemgetter(index)’.  Both functions return
     callables that take a single argument and return the corresponding
     attribute or item; these callables make excellent data extractors
     when used with *note map(): 86a. or *note sorted(): bed.  For
     example:

          >>> L = [('c', 2), ('d', 1), ('a', 4), ('b', 3)]
          >>> map(operator.itemgetter(0), L)
          ['c', 'd', 'a', 'b']
          >>> map(operator.itemgetter(1), L)
          [2, 1, 4, 3]
          >>> sorted(L, key=operator.itemgetter(1)) # Sort list by second tuple item
          [('d', 1), ('c', 2), ('b', 3), ('a', 4)]

     (Contributed by Raymond Hettinger.)

   * The *note optparse: a0. module was updated in various ways.  The
     module now passes its messages through *note gettext.gettext():
     14b8, making it possible to internationalize Optik’s help and error
     messages.  Help messages for options can now include the string
     ‘'%default'’, which will be replaced by the option’s default value.
     (Contributed by Greg Ward.)

   * The long-term plan is to deprecate the ‘rfc822’ module in some
     future Python release in favor of the *note email: 3b. package.  To
     this end, the *note email.Utils.formatdate: 14b9. function has been
     changed to make it usable as a replacement for
     ‘rfc822.formatdate()’.  You may want to write new e-mail processing
     code with this in mind.  (Change implemented by Anthony Baxter.)

   * A new ‘urandom(n)’ function was added to the *note os: a1. module,
     returning a string containing 'n' bytes of random data.  This
     function provides access to platform-specific sources of randomness
     such as ‘/dev/urandom’ on Linux or the Windows CryptoAPI.
     (Contributed by Trevor Perrin.)

   * Another new function: ‘os.path.lexists(path)’ returns true if the
     file specified by 'path' exists, whether or not it’s a symbolic
     link.  This differs from the existing ‘os.path.exists(path)’
     function, which returns false if 'path' is a symlink that points to
     a destination that doesn’t exist.  (Contributed by Beni
     Cherniavsky.)

   * A new ‘getsid()’ function was added to the *note posix: ad. module
     that underlies the *note os: a1. module.  (Contributed by J.
     Raynor.)

   * The *note poplib: ac. module now supports POP over SSL.
     (Contributed by Hector Urtubia.)

   * The *note profile: af. module can now profile C extension
     functions.  (Contributed by Nick Bastin.)

   * The *note random: b8. module has a new method called
     ‘getrandbits(N)’ that returns a long integer 'N' bits in length.
     The existing ‘randrange()’ method now uses ‘getrandbits()’ where
     appropriate, making generation of arbitrarily large random numbers
     more efficient.  (Contributed by Raymond Hettinger.)

   * The regular expression language accepted by the *note re: b9.
     module was extended with simple conditional expressions, written as
     ‘(?(group)A|B)’.  'group' is either a numeric group ID or a group
     name defined with ‘(?P<group>...)’ earlier in the expression.  If
     the specified group matched, the regular expression pattern 'A'
     will be tested against the string; if the group didn’t match, the
     pattern 'B' will be used instead.  (Contributed by Gustavo
     Niemeyer.)

   * The *note re: b9. module is also no longer recursive, thanks to a
     massive amount of work by Gustavo Niemeyer.  In a recursive regular
     expression engine, certain patterns result in a large amount of C
     stack space being consumed, and it was possible to overflow the
     stack.  For example, if you matched a 30000-byte string of ‘a’
     characters against the expression ‘(a|b)+’, one stack frame was
     consumed per character.  Python 2.3 tried to check for stack
     overflow and raise a *note RuntimeError: 195. exception, but
     certain patterns could sidestep the checking and if you were
     unlucky Python could segfault.  Python 2.4’s regular expression
     engine can match this pattern without problems.

   * The *note signal: c6. module now performs tighter error-checking on
     the parameters to the *note signal.signal(): 1178. function.  For
     example, you can’t set a handler on the ‘SIGKILL’ signal; previous
     versions of Python would quietly accept this, but 2.4 will raise a
     *note RuntimeError: 195. exception.

   * Two new functions were added to the *note socket: cc. module.
     ‘socketpair()’ returns a pair of connected sockets and
     ‘getservbyport(port)’ looks up the service name for a given port
     number.  (Contributed by Dave Cole and Barry Warsaw.)

   * The ‘sys.exitfunc()’ function has been deprecated.  Code should be
     using the existing *note atexit: c. module, which correctly handles
     calling multiple exit functions.  Eventually ‘sys.exitfunc()’ will
     become a purely internal interface, accessed only by ‘atexit’.

   * The *note tarfile: de. module now generates GNU-format tar files by
     default.  (Contributed by Lars Gustäbel.)

   * The *note threading: ed. module now has an elegantly simple way to
     support thread-local data.  The module contains a ‘local’ class
     whose attribute values are local to different threads.

          import threading

          data = threading.local()
          data.number = 42
          data.url = ('www.python.org', 80)

     Other threads can assign and retrieve their own values for the
     ‘number’ and ‘url’ attributes.  You can subclass ‘local’ to
     initialize attributes or to add methods.  (Contributed by Jim
     Fulton.)

   * The *note timeit: ef. module now automatically disables periodic
     garbage collection during the timing loop.  This change makes
     consecutive timings more comparable.  (Contributed by Raymond
     Hettinger.)

   * The *note weakref: 114. module now supports a wider variety of
     objects including Python functions, class instances, sets,
     frozensets, deques, arrays, files, sockets, and regular expression
     pattern objects.  (Contributed by Raymond Hettinger.)

   * The *note xmlrpclib: 12e. module now supports a multi-call
     extension for transmitting multiple XML-RPC calls in a single HTTP
     operation.  (Contributed by Brian Quinlan.)

   * The ‘mpz’, ‘rotor’, and ‘xreadlines’ modules have been removed.

* Menu:

* cookielib::
* doctest: doctest<5>.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3548.html


File: python.info,  Node: cookielib,  Next: doctest<5>,  Up: New Improved and Deprecated Modules<3>

1.18.12.1 cookielib
...................

The *note cookielib: 70. library supports client-side handling for HTTP
cookies, mirroring the *note Cookie: 71. module’s server-side cookie
support.  Cookies are stored in cookie jars; the library transparently
stores cookies offered by the web server in the cookie jar, and fetches
the cookie from the jar when connecting to the server.  As in web
browsers, policy objects control whether cookies are accepted or not.

In order to store cookies across sessions, two implementations of cookie
jars are provided: one that stores cookies in the Netscape format so
applications can use the Mozilla or Lynx cookie files, and one that
stores cookies in the same format as the Perl libwww library.

*note urllib2: 10b. has been changed to interact with *note cookielib:
70.: ‘HTTPCookieProcessor’ manages a cookie jar that is used when
accessing URLs.

This module was contributed by John J. Lee.


File: python.info,  Node: doctest<5>,  Prev: cookielib,  Up: New Improved and Deprecated Modules<3>

1.18.12.2 doctest
.................

The *note doctest: 3a. module underwent considerable refactoring thanks
to Edward Loper and Tim Peters.  Testing can still be as simple as
running *note doctest.testmod(): 14bc, but the refactorings allow
customizing the module’s operation in various ways

The new ‘DocTestFinder’ class extracts the tests from a given object’s
docstrings:

     def f (x, y):
         """>>> f(2,2)
     4
     >>> f(3,2)
     6
         """
         return x*y

     finder = doctest.DocTestFinder()

     # Get list of DocTest instances
     tests = finder.find(f)

The new ‘DocTestRunner’ class then runs individual tests and can produce
a summary of the results:

     runner = doctest.DocTestRunner()
     for t in tests:
         tried, failed = runner.run(t)

     runner.summarize(verbose=1)

The above example produces the following output:

     1 items passed all tests:
        2 tests in f
     2 tests in 1 items.
     2 passed and 0 failed.
     Test passed.

‘DocTestRunner’ uses an instance of the ‘OutputChecker’ class to compare
the expected output with the actual output.  This class takes a number
of different flags that customize its behaviour; ambitious users can
also write a completely new subclass of ‘OutputChecker’.

The default output checker provides a number of handy features.  For
example, with the *note doctest.ELLIPSIS: 14bd. option flag, an ellipsis
(‘...’) in the expected output matches any substring, making it easier
to accommodate outputs that vary in minor ways:

     def o (n):
         """>>> o(1)
     <__main__.C instance at 0x...>
     >>>
     """

Another special string, ‘<BLANKLINE>’, matches a blank line:

     def p (n):
         """>>> p(1)
     <BLANKLINE>
     >>>
     """

Another new capability is producing a diff-style display of the output
by specifying the *note doctest.REPORT_UDIFF: 14be. (unified diffs),
*note doctest.REPORT_CDIFF: 14bf. (context diffs), or *note
doctest.REPORT_NDIFF: 14c0. (delta-style) option flags.  For example:

     def g (n):
         """>>> g(4)
     here
     is
     a
     lengthy
     >>>"""
         L = 'here is a rather lengthy list of words'.split()
         for word in L[:n]:
             print word

Running the above function’s tests with *note doctest.REPORT_UDIFF:
14be. specified, you get the following output:

     **********************************************************************
     File "t.py", line 15, in g
     Failed example:
         g(4)
     Differences (unified diff with -expected +actual):
         @@ -2,3 +2,3 @@
          is
          a
         -lengthy
         +rather
     **********************************************************************


File: python.info,  Node: Build and C API Changes<11>,  Next: Porting to Python 2 4,  Prev: New Improved and Deprecated Modules<3>,  Up: What’s New in Python 2 4

1.18.13 Build and C API Changes
-------------------------------

Some of the changes to Python’s build process and to the C API are:

   * Three new convenience macros were added for common return values
     from extension functions: *note Py_RETURN_NONE: 14c2, *note
     Py_RETURN_TRUE: 14c3, and *note Py_RETURN_FALSE: 14c4.
     (Contributed by Brett Cannon.)

   * Another new macro, *note Py_CLEAR: 57b, decreases the reference
     count of 'obj' and sets 'obj' to the null pointer.  (Contributed by
     Jim Fulton.)

   * A new function, ‘PyTuple_Pack(N, obj1, obj2, ..., objN)’,
     constructs tuples from a variable length argument list of Python
     objects.  (Contributed by Raymond Hettinger.)

   * A new function, ‘PyDict_Contains(d, k)’, implements fast dictionary
     lookups without masking exceptions raised during the look-up
     process.  (Contributed by Raymond Hettinger.)

   * The *note Py_IS_NAN: 14c5.(X) macro returns 1 if its float or
     double argument 'X' is a NaN. (Contributed by Tim Peters.)

   * C code can avoid unnecessary locking by using the new
     ‘PyEval_ThreadsInitialized()’ function to tell if any thread
     operations have been performed.  If this function returns false, no
     lock operations are needed.  (Contributed by Nick Coghlan.)

   * A new function, *note PyArg_VaParseTupleAndKeywords(): 387, is the
     same as *note PyArg_ParseTupleAndKeywords(): 386. but takes a
     ‘va_list’ instead of a number of arguments.  (Contributed by Greg
     Chapman.)

   * A new method flag, *note METH_COEXIST: 14c6, allows a function
     defined in slots to co-exist with a *note PyCFunction: 14c7. having
     the same name.  This can halve the access time for a method such as
     ‘set.__contains__()’.  (Contributed by Raymond Hettinger.)

   * Python can now be built with additional profiling for the
     interpreter itself, intended as an aid to people developing the
     Python core.  Providing ‘--enable-profiling’ to the ‘configure’
     script will let you profile the interpreter with ‘gprof’, and
     providing the ‘--with-tsc’ switch enables profiling using the
     Pentium’s Time-Stamp-Counter register.  Note that the ‘--with-tsc’
     switch is slightly misnamed, because the profiling feature also
     works on the PowerPC platform, though that processor architecture
     doesn’t call that register “the TSC register”.  (Contributed by
     Jeremy Hylton.)

   * The ‘tracebackobject’ type has been renamed to ‘PyTracebackObject’.

* Menu:

* Port-Specific Changes: Port-Specific Changes<2>.


File: python.info,  Node: Port-Specific Changes<2>,  Up: Build and C API Changes<11>

1.18.13.1 Port-Specific Changes
...............................

   * The Windows port now builds under MSVC++ 7.1 as well as version 6.
     (Contributed by Martin von Löwis.)


File: python.info,  Node: Porting to Python 2 4,  Next: Acknowledgements<4>,  Prev: Build and C API Changes<11>,  Up: What’s New in Python 2 4

1.18.14 Porting to Python 2.4
-----------------------------

This section lists previously described changes that may require changes
to your code:

   * Left shifts and hexadecimal/octal constants that are too large no
     longer trigger a *note FutureWarning: 418. and return a value
     limited to 32 or 64 bits; instead they return a long integer.

   * Integer operations will no longer trigger an ‘OverflowWarning’.
     The ‘OverflowWarning’ warning will disappear in Python 2.5.

   * The *note zip(): 7d4. built-in function and ‘itertools.izip()’ now
     return an empty list instead of raising a *note TypeError: 2c3.
     exception if called with no arguments.

   * You can no longer compare the ‘date’ and *note datetime: 1cc.
     instances provided by the *note datetime: 30. module.  Two
     instances of different classes will now always be unequal, and
     relative comparisons (‘<’, ‘>’) will raise a *note TypeError: 2c3.

   * ‘dircache.listdir()’ now passes exceptions to the caller instead of
     returning empty lists.

   * ‘LexicalHandler.startDTD()’ used to receive the public and system
     IDs in the wrong order.  This has been corrected; applications
     relying on the wrong order need to be fixed.

   * *note fcntl.ioctl(): 14ca. now warns if the 'mutate' argument is
     omitted and relevant.

   * The *note tarfile: de. module now generates GNU-format tar files by
     default.

   * Encountering a failure while importing a module no longer leaves a
     partially initialized module object in ‘sys.modules’.

   * *note None: 678. is now a constant; code that binds a new value to
     the name ‘None’ is now a syntax error.

   * The ‘signals.signal()’ function now raises a *note RuntimeError:
     195. exception for certain illegal values; previously these errors
     would pass silently.  For example, you can no longer set a handler
     on the ‘SIGKILL’ signal.


File: python.info,  Node: Acknowledgements<4>,  Prev: Porting to Python 2 4,  Up: What’s New in Python 2 4

1.18.15 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Koray Can, Hye-Shik Chang, Michael Dyck, Raymond Hettinger,
Brian Hurt, Hamish Lawson, Fredrik Lundh, Sean Reifschneider, Sadruddin
Rejeb.


File: python.info,  Node: What’s New in Python 2 3,  Next: What’s New in Python 2 2,  Prev: What’s New in Python 2 4,  Up: What’s New in Python

1.19 What’s New in Python 2.3
=============================


Author: A.M. Kuchling

This article explains the new features in Python 2.3.  Python 2.3 was
released on July 29, 2003.

The main themes for Python 2.3 are polishing some of the features added
in 2.2, adding various small but useful enhancements to the core
language, and expanding the standard library.  The new object model
introduced in the previous version has benefited from 18 months of
bugfixes and from optimization efforts that have improved the
performance of new-style classes.  A few new built-in functions have
been added such as *note sum(): 46d. and *note enumerate(): 14d0.  The
*note in: 2f4. operator can now be used for substring searches (e.g.
‘"ab" in "abc"’ returns *note True: c2d.).

Some of the many new library features include Boolean, set, heap, and
date/time data types, the ability to import modules from ZIP-format
archives, metadata support for the long-awaited Python catalog, an
updated version of IDLE, and modules for logging messages, wrapping
text, parsing CSV files, processing command-line options, using
BerkeleyDB databases… the list of new and enhanced modules is lengthy.

This article doesn’t attempt to provide a complete specification of the
new features, but instead provides a convenient overview.  For full
details, you should refer to the documentation for Python 2.3, such as
the Python Library Reference and the Python Reference Manual.  If you
want to understand the complete implementation and design rationale,
refer to the PEP for a particular new feature.

* Menu:

* PEP 218; A Standard Set Datatype: PEP 218 A Standard Set Datatype.
* PEP 255; Simple Generators: PEP 255 Simple Generators.
* PEP 263; Source Code Encodings: PEP 263 Source Code Encodings.
* PEP 273; Importing Modules from ZIP Archives: PEP 273 Importing Modules from ZIP Archives.
* PEP 277; Unicode file name support for Windows NT: PEP 277 Unicode file name support for Windows NT.
* PEP 278; Universal Newline Support: PEP 278 Universal Newline Support.
* PEP 279; enumerate(): PEP 279 enumerate.
* PEP 282; The logging Package: PEP 282 The logging Package.
* PEP 285; A Boolean Type: PEP 285 A Boolean Type.
* PEP 293; Codec Error Handling Callbacks: PEP 293 Codec Error Handling Callbacks.
* PEP 301; Package Index and Metadata for Distutils: PEP 301 Package Index and Metadata for Distutils.
* PEP 302; New Import Hooks: PEP 302 New Import Hooks.
* PEP 305; Comma-separated Files: PEP 305 Comma-separated Files.
* PEP 307; Pickle Enhancements: PEP 307 Pickle Enhancements.
* Extended Slices::
* Other Language Changes: Other Language Changes<18>.
* New, Improved, and Deprecated Modules: New Improved and Deprecated Modules<4>.
* Pymalloc; A Specialized Object Allocator: Pymalloc A Specialized Object Allocator.
* Build and C API Changes: Build and C API Changes<12>.
* Other Changes and Fixes: Other Changes and Fixes<2>.
* Porting to Python 2.3: Porting to Python 2 3.
* Acknowledgements: Acknowledgements<5>.


File: python.info,  Node: PEP 218 A Standard Set Datatype,  Next: PEP 255 Simple Generators,  Up: What’s New in Python 2 3

1.19.1 PEP 218: A Standard Set Datatype
---------------------------------------

The new ‘sets’ module contains an implementation of a set datatype.  The
‘Set’ class is for mutable sets, sets that can have members added and
removed.  The ‘ImmutableSet’ class is for sets that can’t be modified,
and instances of ‘ImmutableSet’ can therefore be used as dictionary
keys.  Sets are built on top of dictionaries, so the elements within a
set must be hashable.

Here’s a simple example:

     >>> import sets
     >>> S = sets.Set([1,2,3])
     >>> S
     Set([1, 2, 3])
     >>> 1 in S
     True
     >>> 0 in S
     False
     >>> S.add(5)
     >>> S.remove(3)
     >>> S
     Set([1, 2, 5])
     >>>

The union and intersection of sets can be computed with the *note
union(): 14d2. and *note intersection(): 14d3. methods; an alternative
notation uses the bitwise operators ‘&’ and ‘|’.  Mutable sets also have
in-place versions of these methods, ‘union_update()’ and *note
intersection_update(): 14d4.

     >>> S1 = sets.Set([1,2,3])
     >>> S2 = sets.Set([4,5,6])
     >>> S1.union(S2)
     Set([1, 2, 3, 4, 5, 6])
     >>> S1 | S2                  # Alternative notation
     Set([1, 2, 3, 4, 5, 6])
     >>> S1.intersection(S2)
     Set([])
     >>> S1 & S2                  # Alternative notation
     Set([])
     >>> S1.union_update(S2)
     >>> S1
     Set([1, 2, 3, 4, 5, 6])
     >>>

It’s also possible to take the symmetric difference of two sets.  This
is the set of all elements in the union that aren’t in the intersection.
Another way of putting it is that the symmetric difference contains all
elements that are in exactly one set.  Again, there’s an alternative
notation (‘^’), and an in-place version with the ungainly name *note
symmetric_difference_update(): 14d5.

     >>> S1 = sets.Set([1,2,3,4])
     >>> S2 = sets.Set([3,4,5,6])
     >>> S1.symmetric_difference(S2)
     Set([1, 2, 5, 6])
     >>> S1 ^ S2
     Set([1, 2, 5, 6])
     >>>

There are also ‘issubset()’ and ‘issuperset()’ methods for checking
whether one set is a subset or superset of another:

     >>> S1 = sets.Set([1,2,3])
     >>> S2 = sets.Set([2,3])
     >>> S2.issubset(S1)
     True
     >>> S1.issubset(S2)
     False
     >>> S1.issuperset(S2)
     True
     >>>

See also
........

PEP 218(1) - Adding a Built-In Set Object Type

     PEP written by Greg V. Wilson.  Implemented by Greg V. Wilson, Alex
     Martelli, and GvR.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0218/


File: python.info,  Node: PEP 255 Simple Generators,  Next: PEP 263 Source Code Encodings,  Prev: PEP 218 A Standard Set Datatype,  Up: What’s New in Python 2 3

1.19.2 PEP 255: Simple Generators
---------------------------------

In Python 2.2, generators were added as an optional feature, to be
enabled by a ‘from __future__ import generators’ directive.  In 2.3
generators no longer need to be specially enabled, and are now always
present; this means that *note yield: 9d8. is now always a keyword.  The
rest of this section is a copy of the description of generators from the
“What’s New in Python 2.2” document; if you read it back when Python 2.2
came out, you can skip the rest of this section.

You’re doubtless familiar with how function calls work in Python or C.
When you call a function, it gets a private namespace where its local
variables are created.  When the function reaches a *note return: 9d9.
statement, the local variables are destroyed and the resulting value is
returned to the caller.  A later call to the same function will get a
fresh new set of local variables.  But, what if the local variables
weren’t thrown away on exiting a function?  What if you could later
resume the function where it left off?  This is what generators provide;
they can be thought of as resumable functions.

Here’s the simplest example of a generator function:

     def generate_ints(N):
         for i in range(N):
             yield i

A new keyword, *note yield: 9d8, was introduced for generators.  Any
function containing a ‘yield’ statement is a generator function; this is
detected by Python’s bytecode compiler which compiles the function
specially as a result.

When you call a generator function, it doesn’t return a single value;
instead it returns a generator object that supports the iterator
protocol.  On executing the *note yield: 9d8. statement, the generator
outputs the value of ‘i’, similar to a *note return: 9d9. statement.
The big difference between ‘yield’ and a ‘return’ statement is that on
reaching a ‘yield’ the generator’s state of execution is suspended and
local variables are preserved.  On the next call to the generator’s
‘.next()’ method, the function will resume executing immediately after
the ‘yield’ statement.  (For complicated reasons, the ‘yield’ statement
isn’t allowed inside the *note try: 6ec. block of a ‘try’…‘finally’
statement; read PEP 255(1) for a full explanation of the interaction
between ‘yield’ and exceptions.)

Here’s a sample usage of the ‘generate_ints()’ generator:

     >>> gen = generate_ints(3)
     >>> gen
     <generator object at 0x8117f90>
     >>> gen.next()
     0
     >>> gen.next()
     1
     >>> gen.next()
     2
     >>> gen.next()
     Traceback (most recent call last):
       File "stdin", line 1, in ?
       File "stdin", line 2, in generate_ints
     StopIteration

You could equally write ‘for i in generate_ints(5)’, or ‘a,b,c =
generate_ints(3)’.

Inside a generator function, the *note return: 9d9. statement can only
be used without a value, and signals the end of the procession of
values; afterwards the generator cannot return any further values.
‘return’ with a value, such as ‘return 5’, is a syntax error inside a
generator function.  The end of the generator’s results can also be
indicated by raising *note StopIteration: c1b. manually, or by just
letting the flow of execution fall off the bottom of the function.

You could achieve the effect of generators manually by writing your own
class and storing all the local variables of the generator as instance
variables.  For example, returning a list of integers could be done by
setting ‘self.count’ to 0, and having the *note next(): 7dc. method
increment ‘self.count’ and return it.  However, for a moderately
complicated generator, writing a corresponding class would be much
messier.  ‘Lib/test/test_generators.py’ contains a number of more
interesting examples.  The simplest one implements an in-order traversal
of a tree using generators recursively.

     # A recursive generator that generates Tree leaves in in-order.
     def inorder(t):
         if t:
             for x in inorder(t.left):
                 yield x
             yield t.label
             for x in inorder(t.right):
                 yield x

Two other examples in ‘Lib/test/test_generators.py’ produce solutions
for the N-Queens problem (placing $N$ queens on an $NxN$ chess board so
that no queen threatens another) and the Knight’s Tour (a route that
takes a knight to every square of an $NxN$ chessboard without visiting
any square twice).

The idea of generators comes from other programming languages,
especially Icon (‘https://www2.cs.arizona.edu/icon/’), where the idea of
generators is central.  In Icon, every expression and function call
behaves like a generator.  One example from “An Overview of the Icon
Programming Language” at
‘https://www2.cs.arizona.edu/icon/docs/ipd266.htm’ gives an idea of what
this looks like:

     sentence := "Store it in the neighboring harbor"
     if (i := find("or", sentence)) > 5 then write(i)

In Icon the ‘find()’ function returns the indexes at which the substring
“or” is found: 3, 23, 33.  In the *note if: 2f3. statement, ‘i’ is first
assigned a value of 3, but 3 is less than 5, so the comparison fails,
and Icon retries it with the second value of 23.  23 is greater than 5,
so the comparison now succeeds, and the code prints the value 23 to the
screen.

Python doesn’t go nearly as far as Icon in adopting generators as a
central concept.  Generators are considered part of the core Python
language, but learning or using them isn’t compulsory; if they don’t
solve any problems that you have, feel free to ignore them.  One novel
feature of Python’s interface as compared to Icon’s is that a
generator’s state is represented as a concrete object (the iterator)
that can be passed around to other functions or stored in a data
structure.

See also
........

PEP 255(2) - Simple Generators

     Written by Neil Schemenauer, Tim Peters, Magnus Lie Hetland.
     Implemented mostly by Neil Schemenauer and Tim Peters, with other
     fixes from the Python Labs crew.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0255/

   (2) https://peps.python.org/pep-0255/


File: python.info,  Node: PEP 263 Source Code Encodings,  Next: PEP 273 Importing Modules from ZIP Archives,  Prev: PEP 255 Simple Generators,  Up: What’s New in Python 2 3

1.19.3 PEP 263: Source Code Encodings
-------------------------------------

Python source files can now be declared as being in different character
set encodings.  Encodings are declared by including a specially
formatted comment in the first or second line of the source file.  For
example, a UTF-8 file can be declared with:

     #!/usr/bin/env python
     # -*- coding: UTF-8 -*-

Without such an encoding declaration, the default encoding used is 7-bit
ASCII. Executing or importing modules that contain string literals with
8-bit characters and have no encoding declaration will result in a *note
DeprecationWarning: 1a5. being signalled by Python 2.3; in 2.4 this will
be a syntax error.

The encoding declaration only affects Unicode string literals, which
will be converted to Unicode using the specified encoding.  Note that
Python identifiers are still restricted to ASCII characters, so you
can’t have variable names that use characters outside of the usual
alphanumerics.

See also
........

PEP 263(1) - Defining Python Source Code Encodings

     Written by Marc-André Lemburg and Martin von Löwis; implemented by
     Suzuki Hisao and Martin von Löwis.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0263/


File: python.info,  Node: PEP 273 Importing Modules from ZIP Archives,  Next: PEP 277 Unicode file name support for Windows NT,  Prev: PEP 263 Source Code Encodings,  Up: What’s New in Python 2 3

1.19.4 PEP 273: Importing Modules from ZIP Archives
---------------------------------------------------

The new *note zipimport: 132. module adds support for importing modules
from a ZIP-format archive.  You don’t need to import the module
explicitly; it will be automatically imported if a ZIP archive’s
filename is added to ‘sys.path’.  For example:

     amk@nyman:~/src/python$ unzip -l /tmp/example.zip
     Archive:  /tmp/example.zip
       Length     Date   Time    Name
      --------    ----   ----    ----
          8467  11-26-02 22:30   jwzthreading.py
      --------                   -------
          8467                   1 file
     amk@nyman:~/src/python$ ./python
     Python 2.3 (#1, Aug 1 2003, 19:54:32)
     >>> import sys
     >>> sys.path.insert(0, '/tmp/example.zip')  # Add .zip file to front of path
     >>> import jwzthreading
     >>> jwzthreading.__file__
     '/tmp/example.zip/jwzthreading.py'
     >>>

An entry in ‘sys.path’ can now be the filename of a ZIP archive.  The
ZIP archive can contain any kind of files, but only files named ‘*.py’,
‘*.pyc’, or ‘*.pyo’ can be imported.  If an archive only contains ‘*.py’
files, Python will not attempt to modify the archive by adding the
corresponding ‘*.pyc’ file, meaning that if a ZIP archive doesn’t
contain ‘*.pyc’ files, importing may be rather slow.

A path within the archive can also be specified to only import from a
subdirectory; for example, the path ‘/tmp/example.zip/lib/’ would only
import from the ‘lib/’ subdirectory within the archive.

See also
........

PEP 273(1) - Import Modules from Zip Archives

     Written by James C. Ahlstrom, who also provided an implementation.
     Python 2.3 follows the specification in PEP 273(2), but uses an
     implementation written by Just van Rossum that uses the import
     hooks described in PEP 302(3).  See section *note PEP 302; New
     Import Hooks: 14db. for a description of the new import hooks.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0273/

   (2) https://peps.python.org/pep-0273/

   (3) https://peps.python.org/pep-0302/


File: python.info,  Node: PEP 277 Unicode file name support for Windows NT,  Next: PEP 278 Universal Newline Support,  Prev: PEP 273 Importing Modules from ZIP Archives,  Up: What’s New in Python 2 3

1.19.5 PEP 277: Unicode file name support for Windows NT
--------------------------------------------------------

On Windows NT, 2000, and XP, the system stores file names as Unicode
strings.  Traditionally, Python has represented file names as byte
strings, which is inadequate because it renders some file names
inaccessible.

Python now allows using arbitrary Unicode strings (within the
limitations of the file system) for all functions that expect file
names, most notably the *note open(): 51f. built-in function.  If a
Unicode string is passed to *note os.listdir(): 113e, Python now returns
a list of Unicode strings.  A new function, ‘os.getcwdu()’, returns the
current directory as a Unicode string.

Byte strings still work as file names, and on Windows Python will
transparently convert them to Unicode using the ‘mbcs’ encoding.

Other systems also allow Unicode strings as file names but convert them
to byte strings before passing them to the system, which can cause a
*note UnicodeError: 12eb. to be raised.  Applications can test whether
arbitrary Unicode strings are supported as file names by checking *note
os.path.supports_unicode_filenames: 14dd, a Boolean value.

Under MacOS, *note os.listdir(): 113e. may now return Unicode filenames.

See also
........

PEP 277(1) - Unicode file name support for Windows NT

     Written by Neil Hodgson; implemented by Neil Hodgson, Martin von
     Löwis, and Mark Hammond.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0277/


File: python.info,  Node: PEP 278 Universal Newline Support,  Next: PEP 279 enumerate,  Prev: PEP 277 Unicode file name support for Windows NT,  Up: What’s New in Python 2 3

1.19.6 PEP 278: Universal Newline Support
-----------------------------------------

The three major operating systems used today are Microsoft Windows,
Apple’s Macintosh OS, and the various Unix derivatives.  A minor
irritation of cross-platform work is that these three platforms all use
different characters to mark the ends of lines in text files.  Unix uses
the linefeed (ASCII character 10), MacOS uses the carriage return (ASCII
character 13), and Windows uses a two-character sequence of a carriage
return plus a newline.

Python’s file objects can now support end of line conventions other than
the one followed by the platform on which Python is running.  Opening a
file with the mode ‘'U'’ or ‘'rU'’ will open a file for reading in *note
universal newlines: d62. mode.  All three line ending conventions will
be translated to a ‘'\n'’ in the strings returned by the various file
methods such as ‘read()’ and ‘readline()’.

Universal newline support is also used when importing modules and when
executing a file with the ‘execfile()’ function.  This means that Python
modules can be shared between all three operating systems without
needing to convert the line-endings.

This feature can be disabled when compiling Python by specifying the
‘--without-universal-newlines’ switch when running Python’s ‘configure’
script.

See also
........

PEP 278(1) - Universal Newline Support

     Written and implemented by Jack Jansen.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0278/


File: python.info,  Node: PEP 279 enumerate,  Next: PEP 282 The logging Package,  Prev: PEP 278 Universal Newline Support,  Up: What’s New in Python 2 3

1.19.7 PEP 279: enumerate()
---------------------------

A new built-in function, *note enumerate(): 14d0, will make certain
loops a bit clearer.  ‘enumerate(thing)’, where 'thing' is either an
iterator or a sequence, returns an iterator that will return ‘(0,
thing[0])’, ‘(1, thing[1])’, ‘(2, thing[2])’, and so forth.

A common idiom to change every element of a list looks like this:

     for i in range(len(L)):
         item = L[i]
         # ... compute some result based on item ...
         L[i] = result

This can be rewritten using *note enumerate(): 14d0. as:

     for i, item in enumerate(L):
         # ... compute some result based on item ...
         L[i] = result

See also
........

PEP 279(1) - The enumerate() built-in function

     Written and implemented by Raymond D. Hettinger.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0279/


File: python.info,  Node: PEP 282 The logging Package,  Next: PEP 285 A Boolean Type,  Prev: PEP 279 enumerate,  Up: What’s New in Python 2 3

1.19.8 PEP 282: The logging Package
-----------------------------------

A standard package for writing logs, *note logging: 87, has been added
to Python 2.3.  It provides a powerful and flexible mechanism for
generating logging output which can then be filtered and processed in
various ways.  A configuration file written in a standard format can be
used to control the logging behavior of a program.  Python includes
handlers that will write log records to standard error or to a file or
socket, send them to the system log, or even e-mail them to a particular
address; of course, it’s also possible to write your own handler
classes.

The *note Logger: b6a. class is the primary class.  Most application
code will deal with one or more ‘Logger’ objects, each one used by a
particular subsystem of the application.  Each ‘Logger’ is identified by
a name, and names are organized into a hierarchy using ‘.’ as the
component separator.  For example, you might have ‘Logger’ instances
named ‘server’, ‘server.auth’ and ‘server.network’.  The latter two
instances are below ‘server’ in the hierarchy.  This means that if you
turn up the verbosity for ‘server’ or direct ‘server’ messages to a
different handler, the changes will also apply to records logged to
‘server.auth’ and ‘server.network’.  There’s also a root ‘Logger’ that’s
the parent of all other loggers.

For simple uses, the *note logging: 87. package contains some
convenience functions that always use the root log:

     import logging

     logging.debug('Debugging information')
     logging.info('Informational message')
     logging.warning('Warning:config file %s not found', 'server.conf')
     logging.error('Error occurred')
     logging.critical('Critical error -- shutting down')

This produces the following output:

     WARNING:root:Warning:config file server.conf not found
     ERROR:root:Error occurred
     CRITICAL:root:Critical error -- shutting down

In the default configuration, informational and debugging messages are
suppressed and the output is sent to standard error.  You can enable the
display of informational and debugging messages by calling the *note
setLevel(): 14e2. method on the root logger.

Notice the *note warning(): 2ff. call’s use of string formatting
operators; all of the functions for logging messages take the arguments
‘(msg, arg1, arg2, ...)’ and log the string resulting from ‘msg % (arg1,
arg2, ...)’.

There’s also an *note exception(): 14e3. function that records the most
recent traceback.  Any of the other functions will also record the
traceback if you specify a true value for the keyword argument
'exc_info'.

     def f():
         try:    1/0
         except: logging.exception('Problem recorded')

     f()

This produces the following output:

     ERROR:root:Problem recorded
     Traceback (most recent call last):
       File "t.py", line 6, in f
         1/0
     ZeroDivisionError: integer division or modulo by zero

Slightly more advanced programs will use a logger other than the root
logger.  The ‘getLogger(name)’ function is used to get a particular log,
creating it if it doesn’t exist yet.  ‘getLogger(None)’ returns the root
logger.

     log = logging.getLogger('server')
      ...
     log.info('Listening on port %i', port)
      ...
     log.critical('Disk full')
      ...

Log records are usually propagated up the hierarchy, so a message logged
to ‘server.auth’ is also seen by ‘server’ and ‘root’, but a *note
Logger: b6a. can prevent this by setting its *note propagate: 14e4.
attribute to *note False: b4f.

There are more classes provided by the *note logging: 87. package that
can be customized.  When a *note Logger: b6a. instance is told to log a
message, it creates a *note LogRecord: 1021. instance that is sent to
any number of different *note Handler: 14e5. instances.  Loggers and
handlers can also have an attached list of filters, and each filter can
cause the ‘LogRecord’ to be ignored or can modify the record before
passing it along.  When they’re finally output, ‘LogRecord’ instances
are converted to text by a *note Formatter: 14e6. class.  All of these
classes can be replaced by your own specially written classes.

With all of these features the *note logging: 87. package should provide
enough flexibility for even the most complicated applications.  This is
only an incomplete overview of its features, so please see the package’s
reference documentation for all of the details.  Reading PEP 282(1) will
also be helpful.

See also
........

PEP 282(2) - A Logging System

     Written by Vinay Sajip and Trent Mick; implemented by Vinay Sajip.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0282/

   (2) https://peps.python.org/pep-0282/


File: python.info,  Node: PEP 285 A Boolean Type,  Next: PEP 293 Codec Error Handling Callbacks,  Prev: PEP 282 The logging Package,  Up: What’s New in Python 2 3

1.19.9 PEP 285: A Boolean Type
------------------------------

A Boolean type was added to Python 2.3.  Two new constants were added to
the ‘__builtin__’ module, *note True: c2d. and *note False: b4f.
(‘True’ and ‘False’ constants were added to the built-ins in Python
2.2.1, but the 2.2.1 versions are simply set to integer values of 1 and
0 and aren’t a different type.)

The type object for this new type is named *note bool: 46b.; the
constructor for it takes any Python value and converts it to *note True:
c2d. or *note False: b4f.

     >>> bool(1)
     True
     >>> bool(0)
     False
     >>> bool([])
     False
     >>> bool( (1,) )
     True

Most of the standard library modules and built-in functions have been
changed to return Booleans.

     >>> obj = []
     >>> hasattr(obj, 'append')
     True
     >>> isinstance(obj, list)
     True
     >>> isinstance(obj, tuple)
     False

Python’s Booleans were added with the primary goal of making code
clearer.  For example, if you’re reading a function and encounter the
statement ‘return 1’, you might wonder whether the ‘1’ represents a
Boolean truth value, an index, or a coefficient that multiplies some
other quantity.  If the statement is ‘return True’, however, the meaning
of the return value is quite clear.

Python’s Booleans were 'not' added for the sake of strict type-checking.
A very strict language such as Pascal would also prevent you performing
arithmetic with Booleans, and would require that the expression in an
*note if: 2f3. statement always evaluate to a Boolean result.  Python is
not this strict and never will be, as PEP 285(1) explicitly says.  This
means you can still use any expression in an ‘if’ statement, even ones
that evaluate to a list or tuple or some random object.  The Boolean
type is a subclass of the *note int: 257. class so that arithmetic using
a Boolean still works.

     >>> True + 1
     2
     >>> False + 1
     1
     >>> False * 75
     0
     >>> True * 75
     75

To sum up *note True: c2d. and *note False: b4f. in a sentence: they’re
alternative ways to spell the integer values 1 and 0, with the single
difference that *note str(): 44f. and *note repr(): 803. return the
strings ‘'True'’ and ‘'False'’ instead of ‘'1'’ and ‘'0'’.

See also
........

PEP 285(2) - Adding a bool type

     Written and implemented by GvR.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0285/

   (2) https://peps.python.org/pep-0285/


File: python.info,  Node: PEP 293 Codec Error Handling Callbacks,  Next: PEP 301 Package Index and Metadata for Distutils,  Prev: PEP 285 A Boolean Type,  Up: What’s New in Python 2 3

1.19.10 PEP 293: Codec Error Handling Callbacks
-----------------------------------------------

When encoding a Unicode string into a byte string, unencodable
characters may be encountered.  So far, Python has allowed specifying
the error processing as either “strict” (raising *note UnicodeError:
12eb.), “ignore” (skipping the character), or “replace” (using a
question mark in the output string), with “strict” being the default
behavior.  It may be desirable to specify alternative processing of such
errors, such as inserting an XML character reference or HTML entity
reference into the converted string.

Python now has a flexible framework to add different processing
strategies.  New error handlers can be added with *note
codecs.register_error(): 14ea, and codecs then can access the error
handler with *note codecs.lookup_error(): 14eb.  An equivalent C API has
been added for codecs written in C. The error handler gets the necessary
state information such as the string being converted, the position in
the string where the error was detected, and the target encoding.  The
handler can then either raise an exception or return a replacement
string.

Two additional error handlers have been implemented using this
framework: “backslashreplace” uses Python backslash quoting to represent
unencodable characters and “xmlcharrefreplace” emits XML character
references.

See also
........

PEP 293(1) - Codec Error Handling Callbacks

     Written and implemented by Walter Dörwald.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0293/


File: python.info,  Node: PEP 301 Package Index and Metadata for Distutils,  Next: PEP 302 New Import Hooks,  Prev: PEP 293 Codec Error Handling Callbacks,  Up: What’s New in Python 2 3

1.19.11 PEP 301: Package Index and Metadata for Distutils
---------------------------------------------------------

Support for the long-requested Python catalog makes its first appearance
in 2.3.

The heart of the catalog is the new Distutils ‘register’ command.
Running ‘python setup.py register’ will collect the metadata describing
a package, such as its name, version, maintainer, description, &c., and
send it to a central catalog server.  The resulting catalog is available
from ‘https://pypi.org’.

To make the catalog a bit more useful, a new optional 'classifiers'
keyword argument has been added to the Distutils ‘setup()’ function.  A
list of Trove(1)-style strings can be supplied to help classify the
software.

Here’s an example ‘setup.py’ with classifiers, written to be compatible
with older versions of the Distutils:

     from distutils import core
     kw = {'name': "Quixote",
           'version': "0.5.1",
           'description': "A highly Pythonic Web application framework",
           # ...
           }

     if (hasattr(core, 'setup_keywords') and
         'classifiers' in core.setup_keywords):
         kw['classifiers'] = \
             ['Topic :: Internet :: WWW/HTTP :: Dynamic Content',
              'Environment :: No Input/Output (Daemon)',
              'Intended Audience :: Developers'],

     core.setup(**kw)

The full list of classifiers can be obtained by running ‘python setup.py
register --list-classifiers’.

See also
........

PEP 301(2) - Package Index and Metadata for Distutils

     Written and implemented by Richard Jones.

   ---------- Footnotes ----------

   (1) http://catb.org/~esr/trove/

   (2) https://peps.python.org/pep-0301/


File: python.info,  Node: PEP 302 New Import Hooks,  Next: PEP 305 Comma-separated Files,  Prev: PEP 301 Package Index and Metadata for Distutils,  Up: What’s New in Python 2 3

1.19.12 PEP 302: New Import Hooks
---------------------------------

While it’s been possible to write custom import hooks ever since the
‘ihooks’ module was introduced in Python 1.3, no one has ever been
really happy with it because writing new import hooks is difficult and
messy.  There have been various proposed alternatives such as the
‘imputil’ and ‘iu’ modules, but none of them has ever gained much
acceptance, and none of them were easily usable from C code.

PEP 302(1) borrows ideas from its predecessors, especially from Gordon
McMillan’s ‘iu’ module.  Three new items are added to the *note sys: d9.
module:

   * ‘sys.path_hooks’ is a list of callable objects; most often they’ll
     be classes.  Each callable takes a string containing a path and
     either returns an importer object that will handle imports from
     this path or raises an *note ImportError: 41c. exception if it
     can’t handle this path.

   * ‘sys.path_importer_cache’ caches importer objects for each path, so
     ‘sys.path_hooks’ will only need to be traversed once for each path.

   * ‘sys.meta_path’ is a list of importer objects that will be
     traversed before ‘sys.path’ is checked.  This list is initially
     empty, but user code can add objects to it.  Additional built-in
     and frozen modules can be imported by an object added to this list.

Importer objects must have a single method, ‘find_module(fullname,
path=None)’.  'fullname' will be a module or package name, e.g.
‘string’ or ‘distutils.core’.  ‘find_module()’ must return a loader
object that has a single method, ‘load_module(fullname)’, that creates
and returns the corresponding module object.

Pseudo-code for Python’s new import logic, therefore, looks something
like this (simplified a bit; see PEP 302(2) for the full details):

     for mp in sys.meta_path:
         loader = mp(fullname)
         if loader is not None:
             <module> = loader.load_module(fullname)

     for path in sys.path:
         for hook in sys.path_hooks:
             try:
                 importer = hook(path)
             except ImportError:
                 # ImportError, so try the other path hooks
                 pass
             else:
                 loader = importer.find_module(fullname)
                 <module> = loader.load_module(fullname)

     # Not found!
     raise ImportError

See also
........

PEP 302(3) - New Import Hooks

     Written by Just van Rossum and Paul Moore.  Implemented by Just van
     Rossum.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0302/

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-0302/


File: python.info,  Node: PEP 305 Comma-separated Files,  Next: PEP 307 Pickle Enhancements,  Prev: PEP 302 New Import Hooks,  Up: What’s New in Python 2 3

1.19.13 PEP 305: Comma-separated Files
--------------------------------------

Comma-separated files are a format frequently used for exporting data
from databases and spreadsheets.  Python 2.3 adds a parser for
comma-separated files.

Comma-separated format is deceptively simple at first glance:

     Costs,150,200,3.95

Read a line and call ‘line.split(',')’: what could be simpler?  But toss
in string data that can contain commas, and things get more complicated:

     "Costs",150,200,3.95,"Includes taxes, shipping, and sundry items"

A big ugly regular expression can parse this, but using the new *note
csv: 29. package is much simpler:

     import csv

     input = open('datafile', 'rb')
     reader = csv.reader(input)
     for line in reader:
         print line

The *note reader(): 489. function takes a number of different options.
The field separator isn’t limited to the comma and can be changed to any
character, and so can the quoting and line-ending characters.

Different dialects of comma-separated files can be defined and
registered; currently there are two dialects, both used by Microsoft
Excel.  A separate *note csv.writer: 48a. class will generate
comma-separated files from a succession of tuples or lists, quoting
strings that contain the delimiter.

See also
........

PEP 305(1) - CSV File API

     Written and implemented by Kevin Altis, Dave Cole, Andrew McNamara,
     Skip Montanaro, Cliff Wells.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0305/


File: python.info,  Node: PEP 307 Pickle Enhancements,  Next: Extended Slices,  Prev: PEP 305 Comma-separated Files,  Up: What’s New in Python 2 3

1.19.14 PEP 307: Pickle Enhancements
------------------------------------

The *note pickle: a6. and ‘cPickle’ modules received some attention
during the 2.3 development cycle.  In 2.2, new-style classes could be
pickled without difficulty, but they weren’t pickled very compactly; PEP
307(1) quotes a trivial example where a new-style class results in a
pickled string three times longer than that for a classic class.

The solution was to invent a new pickle protocol.  The *note
pickle.dumps(): 14f3. function has supported a text-or-binary flag for a
long time.  In 2.3, this flag is redefined from a Boolean to an integer:
0 is the old text-mode pickle format, 1 is the old binary format, and
now 2 is a new 2.3-specific format.  A new constant, *note
pickle.HIGHEST_PROTOCOL: 14f4, can be used to select the fanciest
protocol available.

Unpickling is no longer considered a safe operation.  2.2’s *note
pickle: a6. provided hooks for trying to prevent unsafe classes from
being unpickled (specifically, a ‘__safe_for_unpickling__’ attribute),
but none of this code was ever audited and therefore it’s all been
ripped out in 2.3.  You should not unpickle untrusted data in any
version of Python.

To reduce the pickling overhead for new-style classes, a new interface
for customizing pickling was added using three special methods: *note
__getstate__(): 5db, *note __setstate__(): 9df, and *note
__getnewargs__(): e04.  Consult PEP 307(2) for the full semantics of
these methods.

As a way to compress pickles yet further, it’s now possible to use
integer codes instead of long strings to identify pickled classes.  The
Python Software Foundation will maintain a list of standardized codes;
there’s also a range of codes for private use.  Currently no codes have
been specified.

See also
........

PEP 307(3) - Extensions to the pickle protocol

     Written and implemented by Guido van Rossum and Tim Peters.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0307/

   (2) https://peps.python.org/pep-0307/

   (3) https://peps.python.org/pep-0307/


File: python.info,  Node: Extended Slices,  Next: Other Language Changes<18>,  Prev: PEP 307 Pickle Enhancements,  Up: What’s New in Python 2 3

1.19.15 Extended Slices
-----------------------

Ever since Python 1.4, the slicing syntax has supported an optional
third “step” or “stride” argument.  For example, these are all legal
Python syntax: ‘L[1:10:2]’, ‘L[:-1:1]’, ‘L[::-1]’.  This was added to
Python at the request of the developers of Numerical Python, which uses
the third argument extensively.  However, Python’s built-in list, tuple,
and string sequence types have never supported this feature, raising a
*note TypeError: 2c3. if you tried it.  Michael Hudson contributed a
patch to fix this shortcoming.

For example, you can now easily extract the elements of a list that have
even indexes:

     >>> L = range(10)
     >>> L[::2]
     [0, 2, 4, 6, 8]

Negative values also work to make a copy of the same list in reverse
order:

     >>> L[::-1]
     [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

This also works for tuples, arrays, and strings:

     >>> s='abcd'
     >>> s[::2]
     'ac'
     >>> s[::-1]
     'dcba'

If you have a mutable sequence such as a list or an array you can assign
to or delete an extended slice, but there are some differences between
assignment to extended and regular slices.  Assignment to a regular
slice can be used to change the length of the sequence:

     >>> a = range(3)
     >>> a
     [0, 1, 2]
     >>> a[1:3] = [4, 5, 6]
     >>> a
     [0, 4, 5, 6]

Extended slices aren’t this flexible.  When assigning to an extended
slice, the list on the right hand side of the statement must contain the
same number of items as the slice it is replacing:

     >>> a = range(4)
     >>> a
     [0, 1, 2, 3]
     >>> a[::2]
     [0, 2]
     >>> a[::2] = [0, -1]
     >>> a
     [0, 1, -1, 3]
     >>> a[::2] = [0,1,2]
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     ValueError: attempt to assign sequence of size 3 to extended slice of size 2

Deletion is more straightforward:

     >>> a = range(4)
     >>> a
     [0, 1, 2, 3]
     >>> a[::2]
     [0, 2]
     >>> del a[::2]
     >>> a
     [1, 3]

One can also now pass slice objects to the *note __getitem__(): 283.
methods of the built-in sequences:

     >>> range(10).__getitem__(slice(0, 5, 2))
     [0, 2, 4]

Or use slice objects directly in subscripts:

     >>> range(10)[slice(0, 5, 2)]
     [0, 2, 4]

To simplify implementing sequences that support extended slicing, slice
objects now have a method ‘indices(length)’ which, given the length of a
sequence, returns a ‘(start, stop, step)’ tuple that can be passed
directly to *note range(): 94d.  ‘indices()’ handles omitted and
out-of-bounds indices in a manner consistent with regular slices (and
this innocuous phrase hides a welter of confusing details!).  The method
is intended to be used like this:

     class FakeSeq:
         ...
         def calc_item(self, i):
             ...
         def __getitem__(self, item):
             if isinstance(item, slice):
                 indices = item.indices(len(self))
                 return FakeSeq([self.calc_item(i) for i in range(*indices)])
             else:
                 return self.calc_item(i)

From this example you can also see that the built-in *note slice: 46c.
object is now the type object for the slice type, and is no longer a
function.  This is consistent with Python 2.2, where *note int: 257,
*note str: 44f, etc., underwent the same change.


File: python.info,  Node: Other Language Changes<18>,  Next: New Improved and Deprecated Modules<4>,  Prev: Extended Slices,  Up: What’s New in Python 2 3

1.19.16 Other Language Changes
------------------------------

Here are all of the changes that Python 2.3 makes to the core Python
language.

   * The *note yield: 9d8. statement is now always a keyword, as
     described in section *note PEP 255; Simple Generators: 14d7. of
     this document.

   * A new built-in function *note enumerate(): 14d0. was added, as
     described in section *note PEP 279; enumerate(): 14e0. of this
     document.

   * Two new constants, *note True: c2d. and *note False: b4f. were
     added along with the built-in *note bool: 46b. type, as described
     in section *note PEP 285; A Boolean Type: 14e8. of this document.

   * The *note int(): 257. type constructor will now return a long
     integer instead of raising an *note OverflowError: 888. when a
     string or floating-point number is too large to fit into an
     integer.  This can lead to the paradoxical result that
     ‘isinstance(int(expression), int)’ is false, but that seems
     unlikely to cause problems in practice.

   * Built-in types now support the extended slicing syntax, as
     described in section *note Extended Slices: 14f6. of this document.

   * A new built-in function, ‘sum(iterable, start=0)’, adds up the
     numeric items in the iterable object and returns their sum.  *note
     sum(): 46d. only accepts numbers, meaning that you can’t use it to
     concatenate a bunch of strings.  (Contributed by Alex Martelli.)

   * ‘list.insert(pos, value)’ used to insert 'value' at the front of
     the list when 'pos' was negative.  The behaviour has now been
     changed to be consistent with slice indexing, so when 'pos' is -1
     the value will be inserted before the last element, and so forth.

   * ‘list.index(value)’, which searches for 'value' within the list and
     returns its index, now takes optional 'start' and 'stop' arguments
     to limit the search to only part of the list.

   * Dictionaries have a new method, ‘pop(key[, *default*])’, that
     returns the value corresponding to 'key' and removes that key/value
     pair from the dictionary.  If the requested key isn’t present in
     the dictionary, 'default' is returned if it’s specified and *note
     KeyError: 345. raised if it isn’t.

          >>> d = {1:2}
          >>> d
          {1: 2}
          >>> d.pop(4)
          Traceback (most recent call last):
            File "stdin", line 1, in ?
          KeyError: 4
          >>> d.pop(1)
          2
          >>> d.pop(1)
          Traceback (most recent call last):
            File "stdin", line 1, in ?
          KeyError: 'pop(): dictionary is empty'
          >>> d
          {}
          >>>

     There’s also a new class method, ‘dict.fromkeys(iterable, value)’,
     that creates a dictionary with keys taken from the supplied
     iterator 'iterable' and all values set to 'value', defaulting to
     ‘None’.

     (Patches contributed by Raymond Hettinger.)

     Also, the *note dict(): 256. constructor now accepts keyword
     arguments to simplify creating small dictionaries:

          >>> dict(red=1, blue=2, green=3, black=4)
          {'blue': 2, 'black': 4, 'green': 3, 'red': 1}

     (Contributed by Just van Rossum.)

   * The *note assert: 972. statement no longer checks the ‘__debug__’
     flag, so you can no longer disable assertions by assigning to
     ‘__debug__’.  Running Python with the *note -O: de3. switch will
     still generate code that doesn’t execute any assertions.

   * Most type objects are now callable, so you can use them to create
     new objects such as functions, classes, and modules.  (This means
     that the ‘new’ module can be deprecated in a future Python version,
     because you can now use the type objects available in the *note
     types: 103. module.)  For example, you can create a new module
     object with the following code:

          >>> import types
          >>> m = types.ModuleType('abc','docstring')
          >>> m
          <module 'abc' (built-in)>
          >>> m.__doc__
          'docstring'

   * A new warning, *note PendingDeprecationWarning: 8d1. was added to
     indicate features which are in the process of being deprecated.
     The warning will 'not' be printed by default.  To check for use of
     features that will be deprecated in the future, supply *note
     -Walways;;PendingDeprecationWarning;;: 8d0. on the command line or
     use *note warnings.filterwarnings(): 14f8.

   * The process of deprecating string-based exceptions, as in ‘raise
     "Error occurred"’, has begun.  Raising a string will now trigger
     *note PendingDeprecationWarning: 8d1.

   * Using ‘None’ as a variable name will now result in a *note
     SyntaxWarning: 469. warning.  In a future version of Python, ‘None’
     may finally become a keyword.

   * The ‘xreadlines()’ method of file objects, introduced in Python
     2.1, is no longer necessary because files now behave as their own
     iterator.  ‘xreadlines()’ was originally introduced as a faster way
     to loop over all the lines in a file, but now you can simply write
     ‘for line in file_obj’.  File objects also have a new read-only
     ‘encoding’ attribute that gives the encoding used by the file;
     Unicode strings written to the file will be automatically converted
     to bytes using the given encoding.

   * The method resolution order used by new-style classes has changed,
     though you’ll only notice the difference if you have a really
     complicated inheritance hierarchy.  Classic classes are unaffected
     by this change.  Python 2.2 originally used a topological sort of a
     class’s ancestors, but 2.3 now uses the C3 algorithm as described
     in the paper "A Monotonic Superclass Linearization for Dylan"(1).
     To understand the motivation for this change, read Michele
     Simionato’s article *note The Python 2.3 Method Resolution Order:
     14f9, or read the thread on python-dev starting with the message at
     ‘https://mail.python.org/pipermail/python-dev/2002-October/029035.html’.
     Samuele Pedroni first pointed out the problem and also implemented
     the fix by coding the C3 algorithm.

   * Python runs multithreaded programs by switching between threads
     after executing N bytecodes.  The default value for N has been
     increased from 10 to 100 bytecodes, speeding up single-threaded
     applications by reducing the switching overhead.  Some
     multithreaded applications may suffer slower response time, but
     that’s easily fixed by setting the limit back to a lower number
     using ‘sys.setcheckinterval(N)’.  The limit can be retrieved with
     the new ‘sys.getcheckinterval()’ function.

   * One minor but far-reaching change is that the names of extension
     types defined by the modules included with Python now contain the
     module and a ‘'.'’ in front of the type name.  For example, in
     Python 2.2, if you created a socket and printed its ‘__class__’,
     you’d get this output:

          >>> s = socket.socket()
          >>> s.__class__
          <type 'socket'>

     In 2.3, you get this:

          >>> s.__class__
          <type '_socket.socket'>

   * One of the noted incompatibilities between old- and new-style
     classes has been removed: you can now assign to the *note __name__:
     14fa. and *note __bases__: 14fb. attributes of new-style classes.
     There are some restrictions on what can be assigned to ‘__bases__’
     along the lines of those relating to assigning to an instance’s
     *note __class__: 14fc. attribute.

* Menu:

* String Changes::
* Optimizations: Optimizations<17>.

   ---------- Footnotes ----------

   (1) https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.19.3910


File: python.info,  Node: String Changes,  Next: Optimizations<17>,  Up: Other Language Changes<18>

1.19.16.1 String Changes
........................

   * The *note in: 2f4. operator now works differently for strings.
     Previously, when evaluating ‘X in Y’ where 'X' and 'Y' are strings,
     'X' could only be a single character.  That’s now changed; 'X' can
     be a string of any length, and ‘X in Y’ will return *note True:
     c2d. if 'X' is a substring of 'Y'. If 'X' is the empty string, the
     result is always ‘True’.

          >>> 'ab' in 'abcd'
          True
          >>> 'ad' in 'abcd'
          False
          >>> '' in 'abcd'
          True

     Note that this doesn’t tell you where the substring starts; if you
     need that information, use the *note find(): edc. string method.

   * The *note strip(): 14fe, *note lstrip(): 14ff, and *note rstrip():
     1500. string methods now have an optional argument for specifying
     the characters to strip.  The default is still to remove all
     whitespace characters:

          >>> '   abc '.strip()
          'abc'
          >>> '><><abc<><><>'.strip('<>')
          'abc'
          >>> '><><abc<><><>\n'.strip('<>')
          'abc<><><>\n'
          >>> u'\u4000\u4001abc\u4000'.strip(u'\u4000')
          u'\u4001abc'
          >>>

     (Suggested by Simon Brunning and implemented by Walter Dörwald.)

   * The *note startswith(): eff. and *note endswith(): f00. string
     methods now accept negative numbers for the 'start' and 'end'
     parameters.

   * Another new string method is *note zfill(): 1501, originally a
     function in the *note string: d3. module.  ‘zfill()’ pads a numeric
     string with zeros on the left until it’s the specified width.  Note
     that the ‘%’ operator is still more flexible and powerful than
     ‘zfill()’.

          >>> '45'.zfill(4)
          '0045'
          >>> '12345'.zfill(4)
          '12345'
          >>> 'goofy'.zfill(6)
          '0goofy'

     (Contributed by Walter Dörwald.)

   * A new type object, ‘basestring’, has been added.  Both 8-bit
     strings and Unicode strings inherit from this type, so
     ‘isinstance(obj, basestring)’ will return *note True: c2d. for
     either kind of string.  It’s a completely abstract type, so you
     can’t create ‘basestring’ instances.

   * Interned strings are no longer immortal and will now be
     garbage-collected in the usual way when the only reference to them
     is from the internal dictionary of interned strings.  (Implemented
     by Oren Tirosh.)


File: python.info,  Node: Optimizations<17>,  Prev: String Changes,  Up: Other Language Changes<18>

1.19.16.2 Optimizations
.......................

   * The creation of new-style class instances has been made much
     faster; they’re now faster than classic classes!

   * The *note sort(): bee. method of list objects has been extensively
     rewritten by Tim Peters, and the implementation is significantly
     faster.

   * Multiplication of large long integers is now much faster thanks to
     an implementation of Karatsuba multiplication, an algorithm that
     scales better than the 'O'('n'^2) required for the grade-school
     multiplication algorithm.  (Original patch by Christopher A. Craig,
     and significantly reworked by Tim Peters.)

   * The ‘SET_LINENO’ opcode is now gone.  This may provide a small
     speed increase, depending on your compiler’s idiosyncrasies.  See
     section *note Other Changes and Fixes: 1503. for a longer
     explanation.  (Removed by Michael Hudson.)

   * ‘xrange()’ objects now have their own iterator, making ‘for i in
     xrange(n)’ slightly faster than ‘for i in range(n)’.  (Patch by
     Raymond Hettinger.)

   * A number of small rearrangements have been made in various hotspots
     to improve performance, such as inlining a function or removing
     some code.  (Implemented mostly by GvR, but lots of people have
     contributed single changes.)

The net result of the 2.3 optimizations is that Python 2.3 runs the
pystone benchmark around 25% faster than Python 2.2.


File: python.info,  Node: New Improved and Deprecated Modules<4>,  Next: Pymalloc A Specialized Object Allocator,  Prev: Other Language Changes<18>,  Up: What’s New in Python 2 3

1.19.17 New, Improved, and Deprecated Modules
---------------------------------------------

As usual, Python’s standard library received a number of enhancements
and bug fixes.  Here’s a partial list of the most notable changes,
sorted alphabetically by module name.  Consult the ‘Misc/NEWS’ file in
the source tree for a more complete list of changes, or look through the
CVS logs for all the details.

   * The *note array: 7. module now supports arrays of Unicode
     characters using the ‘'u'’ format character.  Arrays also now
     support using the ‘+=’ assignment operator to add another array’s
     contents, and the ‘*=’ assignment operator to repeat an array.
     (Contributed by Jason Orendorff.)

   * The ‘bsddb’ module has been replaced by version 4.1.6 of the
     PyBSDDB(1) package, providing a more complete interface to the
     transactional features of the BerkeleyDB library.

     The old version of the module has been renamed to ‘bsddb185’ and is
     no longer built automatically; you’ll have to edit ‘Modules/Setup’
     to enable it.  Note that the new ‘bsddb’ package is intended to be
     compatible with the old module, so be sure to file bugs if you
     discover any incompatibilities.  When upgrading to Python 2.3, if
     the new interpreter is compiled with a new version of the
     underlying BerkeleyDB library, you will almost certainly have to
     convert your database files to the new version.  You can do this
     fairly easily with the new scripts ‘db2pickle.py’ and
     ‘pickle2db.py’ which you will find in the distribution’s
     ‘Tools/scripts’ directory.  If you’ve already been using the
     PyBSDDB package and importing it as ‘bsddb3’, you will have to
     change your ‘import’ statements to import it as ‘bsddb’.

   * The new *note bz2: 13. module is an interface to the bz2 data
     compression library.  bz2-compressed data is usually smaller than
     corresponding *note zlib: 133.-compressed data.  (Contributed by
     Gustavo Niemeyer.)

   * A set of standard date/time types has been added in the new *note
     datetime: 30. module.  See the following section for more details.

   * The Distutils ‘Extension’ class now supports an extra constructor
     argument named 'depends' for listing additional source files that
     an extension depends on.  This lets Distutils recompile the module
     if any of the dependency files are modified.  For example, if
     ‘sampmodule.c’ includes the header file ‘sample.h’, you would
     create the ‘Extension’ object like this:

          ext = Extension("samp",
                          sources=["sampmodule.c"],
                          depends=["sample.h"])

     Modifying ‘sample.h’ would then cause the module to be recompiled.
     (Contributed by Jeremy Hylton.)

   * Other minor changes to Distutils: it now checks for the *note CC:
     1505, *note CFLAGS: 1506, ‘CPP’, *note LDFLAGS: 1507, and *note
     CPPFLAGS: 1508. environment variables, using them to override the
     settings in Python’s configuration (contributed by Robert Weber).

   * Previously the *note doctest: 3a. module would only search the
     docstrings of public methods and functions for test cases, but it
     now also examines private ones as well.  The *note DocTestSuite():
     e25. function creates a *note unittest.TestSuite: e26. object from
     a set of ‘doctest’ tests.

   * The new ‘gc.get_referents(object)’ function returns a list of all
     the objects referenced by 'object'.

   * The *note getopt: 61. module gained a new function, *note
     gnu_getopt(): 1509, that supports the same arguments as the
     existing *note getopt(): 150a. function but uses GNU-style scanning
     mode.  The existing ‘getopt()’ stops processing options as soon as
     a non-option argument is encountered, but in GNU-style mode
     processing continues, meaning that options and arguments can be
     mixed.  For example:

          >>> getopt.getopt(['-f', 'filename', 'output', '-v'], 'f:v')
          ([('-f', 'filename')], ['output', '-v'])
          >>> getopt.gnu_getopt(['-f', 'filename', 'output', '-v'], 'f:v')
          ([('-f', 'filename'), ('-v', '')], ['output'])

     (Contributed by Peter Åstrand.)

   * The *note grp: 66, *note pwd: b2, and *note resource: bc. modules
     now return enhanced tuples:

          >>> import grp
          >>> g = grp.getgrnam('amk')
          >>> g.gr_name, g.gr_gid
          ('amk', 500)

   * The *note gzip: 67. module can now handle files exceeding 2 GiB.

   * The new *note heapq: 69. module contains an implementation of a
     heap queue algorithm.  A heap is an array-like data structure that
     keeps items in a partially sorted order such that, for every index
     'k', ‘heap[k] <= heap[2*k+1]’ and ‘heap[k] <= heap[2*k+2]’.  This
     makes it quick to remove the smallest item, and inserting a new
     item while maintaining the heap property is 'O'(log 'n').  (See
     ‘https://xlinux.nist.gov/dads//HTML/priorityque.html’ for more
     information about the priority queue data structure.)

     The *note heapq: 69. module provides *note heappush(): 150b. and
     *note heappop(): 150c. functions for adding and removing items
     while maintaining the heap property on top of some other mutable
     Python sequence type.  Here’s an example that uses a Python list:

          >>> import heapq
          >>> heap = []
          >>> for item in [3, 7, 5, 11, 1]:
          ...    heapq.heappush(heap, item)
          ...
          >>> heap
          [1, 3, 5, 11, 7]
          >>> heapq.heappop(heap)
          1
          >>> heapq.heappop(heap)
          3
          >>> heap
          [5, 7, 11]

     (Contributed by Kevin O’Connor.)

   * The IDLE integrated development environment has been updated using
     the code from the IDLEfork project
     (‘https://idlefork.sourceforge.net’).  The most notable feature is
     that the code being developed is now executed in a subprocess,
     meaning that there’s no longer any need for manual ‘reload()’
     operations.  IDLE’s core code has been incorporated into the
     standard library as the *note idlelib: 73. package.

   * The *note imaplib: 74. module now supports IMAP over SSL.
     (Contributed by Piers Lauder and Tino Lange.)

   * The *note itertools: 81. contains a number of useful functions for
     use with iterators, inspired by various functions provided by the
     ML and Haskell languages.  For example,
     ‘itertools.ifilter(predicate, iterator)’ returns all elements in
     the iterator for which the function ‘predicate()’ returns *note
     True: c2d, and ‘itertools.repeat(obj, N)’ returns ‘obj’ 'N' times.
     There are a number of other functions in the module; see the
     package’s reference documentation for details.  (Contributed by
     Raymond Hettinger.)

   * Two new functions in the *note math: 8e. module, ‘degrees(rads)’
     and ‘radians(degs)’, convert between radians and degrees.  Other
     functions in the ‘math’ module such as *note math.sin(): 150d. and
     *note math.cos(): 150e. have always required input values measured
     in radians.  Also, an optional 'base' argument was added to *note
     math.log(): 150f. to make it easier to compute logarithms for bases
     other than ‘e’ and ‘10’.  (Contributed by Raymond Hettinger.)

   * Several new POSIX functions (‘getpgid()’, ‘killpg()’, ‘lchown()’,
     ‘loadavg()’, ‘major()’, ‘makedev()’, ‘minor()’, and ‘mknod()’) were
     added to the *note posix: ad. module that underlies the *note os:
     a1. module.  (Contributed by Gustavo Niemeyer, Geert Jansen, and
     Denis S. Otkidach.)

   * In the *note os: a1. module, the ‘*stat()’ family of functions can
     now report fractions of a second in a timestamp.  Such time stamps
     are represented as floats, similar to the value returned by *note
     time.time(): 254.

     During testing, it was found that some applications will break if
     time stamps are floats.  For compatibility, when using the tuple
     interface of the *note stat_result: 1510. time stamps will be
     represented as integers.  When using named fields (a feature first
     introduced in Python 2.2), time stamps are still represented as
     integers, unless ‘os.stat_float_times()’ is invoked to enable float
     return values:

          >>> os.stat("/tmp").st_mtime
          1034791200
          >>> os.stat_float_times(True)
          >>> os.stat("/tmp").st_mtime
          1034791200.6335014

     In Python 2.4, the default will change to always returning floats.

     Application developers should enable this feature only if all their
     libraries work properly when confronted with floating-point time
     stamps, or if they use the tuple API. If used, the feature should
     be activated on an application level instead of trying to enable it
     on a per-use basis.

   * The *note optparse: a0. module contains a new parser for
     command-line arguments that can convert option values to a
     particular Python type and will automatically generate a usage
     message.  See the following section for more details.

   * The old and never-documented ‘linuxaudiodev’ module has been
     deprecated, and a new version named ‘ossaudiodev’ has been added.
     The module was renamed because the OSS sound drivers can be used on
     platforms other than Linux, and the interface has also been tidied
     and brought up to date in various ways.  (Contributed by Greg Ward
     and Nicholas FitzRoy-Dale.)

   * The new *note platform: aa. module contains a number of functions
     that try to determine various properties of the platform you’re
     running on.  There are functions for getting the architecture, CPU
     type, the Windows OS version, and even the Linux distribution
     version.  (Contributed by Marc-André Lemburg.)

   * The parser objects provided by the *note pyexpat: 126. module can
     now optionally buffer character data, resulting in fewer calls to
     your character data handler and therefore faster performance.
     Setting the parser object’s *note buffer_text: 1511. attribute to
     *note True: c2d. will enable buffering.

   * The ‘sample(population, k)’ function was added to the *note random:
     b8. module.  'population' is a sequence or ‘xrange’ object
     containing the elements of a population, and *note sample(): 749.
     chooses 'k' elements from the population without replacing chosen
     elements.  'k' can be any value up to ‘len(population)’.  For
     example:

          >>> days = ['Mo', 'Tu', 'We', 'Th', 'Fr', 'St', 'Sn']
          >>> random.sample(days, 3)      # Choose 3 elements
          ['St', 'Sn', 'Th']
          >>> random.sample(days, 7)      # Choose 7 elements
          ['Tu', 'Th', 'Mo', 'We', 'St', 'Fr', 'Sn']
          >>> random.sample(days, 7)      # Choose 7 again
          ['We', 'Mo', 'Sn', 'Fr', 'Tu', 'St', 'Th']
          >>> random.sample(days, 8)      # Can't choose eight
          Traceback (most recent call last):
            File "<stdin>", line 1, in ?
            File "random.py", line 414, in sample
                raise ValueError, "sample larger than population"
          ValueError: sample larger than population
          >>> random.sample(xrange(1,10000,2), 10)   # Choose ten odd nos. under 10000
          [3407, 3805, 1505, 7023, 2401, 2267, 9733, 3151, 8083, 9195]

     The *note random: b8. module now uses a new algorithm, the Mersenne
     Twister, implemented in C. It’s faster and more extensively studied
     than the previous algorithm.

     (All changes contributed by Raymond Hettinger.)

   * The *note readline: ba. module also gained a number of new
     functions: *note get_history_item(): 1512, *note
     get_current_history_length(): 1513, and *note redisplay(): 1514.

   * The ‘rexec’ and ‘Bastion’ modules have been declared dead, and
     attempts to import them will fail with a *note RuntimeError: 195.
     New-style classes provide new ways to break out of the restricted
     execution environment provided by ‘rexec’, and no one has interest
     in fixing them or time to do so.  If you have applications using
     ‘rexec’, rewrite them to use something else.

     (Sticking with Python 2.2 or 2.1 will not make your applications
     any safer because there are known bugs in the ‘rexec’ module in
     those versions.  To repeat: if you’re using ‘rexec’, stop using it
     immediately.)

   * The ‘rotor’ module has been deprecated because the algorithm it
     uses for encryption is not believed to be secure.  If you need
     encryption, use one of the several AES Python modules that are
     available separately.

   * The *note shutil: c5. module gained a ‘move(src, dest)’ function
     that recursively moves a file or directory to a new location.

   * Support for more advanced POSIX signal handling was added to the
     *note signal: c6. but then removed again as it proved impossible to
     make it work reliably across platforms.

   * The *note socket: cc. module now supports timeouts.  You can call
     the ‘settimeout(t)’ method on a socket object to set a timeout of
     't' seconds.  Subsequent socket operations that take longer than
     't' seconds to complete will abort and raise a *note
     socket.timeout: 83a. exception.

     The original timeout implementation was by Tim O’Malley.  Michael
     Gilfix integrated it into the Python *note socket: cc. module and
     shepherded it through a lengthy review.  After the code was checked
     in, Guido van Rossum rewrote parts of it.  (This is a good example
     of a collaborative development process in action.)

   * On Windows, the *note socket: cc. module now ships with Secure
     Sockets Layer (SSL) support.

   * The value of the C ‘PYTHON_API_VERSION’ macro is now exposed at the
     Python level as ‘sys.api_version’.  The current exception can be
     cleared by calling the new ‘sys.exc_clear()’ function.

   * The new *note tarfile: de. module allows reading from and writing
     to ‘tar’-format archive files.  (Contributed by Lars Gustäbel.)

   * The new *note textwrap: ec. module contains functions for wrapping
     strings containing paragraphs of text.  The ‘wrap(text, width)’
     function takes a string and returns a list containing the text
     split into lines of no more than the chosen width.  The ‘fill(text,
     width)’ function returns a single string, reformatted to fit into
     lines no longer than the chosen width.  (As you can guess, *note
     fill(): 1515. is built on top of *note wrap(): 1516.  For example:

          >>> import textwrap
          >>> paragraph = "Not a whit, we defy augury: ... more text ..."
          >>> textwrap.wrap(paragraph, 60)
          ["Not a whit, we defy augury: there's a special providence in",
           "the fall of a sparrow. If it be now, 'tis not to come; if it",
           ...]
          >>> print textwrap.fill(paragraph, 35)
          Not a whit, we defy augury: there's
          a special providence in the fall of
          a sparrow. If it be now, 'tis not
          to come; if it be not to come, it
          will be now; if it be not now, yet
          it will come: the readiness is all.
          >>>

     The module also contains a *note TextWrapper: 1008. class that
     actually implements the text wrapping strategy.  Both the
     ‘TextWrapper’ class and the *note wrap(): 1516. and *note fill():
     1515. functions support a number of additional keyword arguments
     for fine-tuning the formatting; consult the module’s documentation
     for details.  (Contributed by Greg Ward.)

   * The ‘thread’ and *note threading: ed. modules now have companion
     modules, ‘dummy_thread’ and ‘dummy_threading’, that provide a
     do-nothing implementation of the ‘thread’ module’s interface for
     platforms where threads are not supported.  The intention is to
     simplify thread-aware modules (ones that 'don’t' rely on threads to
     run) by putting the following code at the top:

          try:
              import threading as _threading
          except ImportError:
              import dummy_threading as _threading

     In this example, ‘_threading’ is used as the module name to make it
     clear that the module being used is not necessarily the actual
     *note threading: ed. module.  Code can call functions and use
     classes in ‘_threading’ whether or not threads are supported,
     avoiding an *note if: 2f3. statement and making the code slightly
     clearer.  This module will not magically make multithreaded code
     run without threads; code that waits for another thread to return
     or to do something will simply hang forever.

   * The *note time: ee. module’s *note strptime(): 147b. function has
     long been an annoyance because it uses the platform C library’s
     ‘strptime()’ implementation, and different platforms sometimes have
     odd bugs.  Brett Cannon contributed a portable implementation
     that’s written in pure Python and should behave identically on all
     platforms.

   * The new *note timeit: ef. module helps measure how long snippets of
     Python code take to execute.  The ‘timeit.py’ file can be run
     directly from the command line, or the module’s *note Timer: 1517.
     class can be imported and used directly.  Here’s a short example
     that figures out whether it’s faster to convert an 8-bit string to
     Unicode by appending an empty Unicode string to it or by using the
     ‘unicode()’ function:

          import timeit

          timer1 = timeit.Timer('unicode("abc")')
          timer2 = timeit.Timer('"abc" + u""')

          # Run three trials
          print timer1.repeat(repeat=3, number=100000)
          print timer2.repeat(repeat=3, number=100000)

          # On my laptop this outputs:
          # [0.36831796169281006, 0.37441694736480713, 0.35304892063140869]
          # [0.17574405670166016, 0.18193507194519043, 0.17565798759460449]

   * The ‘Tix’ module has received various bug fixes and updates for the
     current version of the Tix package.

   * The ‘Tkinter’ module now works with a thread-enabled version of
     Tcl.  Tcl’s threading model requires that widgets only be accessed
     from the thread in which they’re created; accesses from another
     thread can cause Tcl to panic.  For certain Tcl interfaces,
     ‘Tkinter’ will now automatically avoid this when a widget is
     accessed from a different thread by marshalling a command, passing
     it to the correct thread, and waiting for the results.  Other
     interfaces can’t be handled automatically but ‘Tkinter’ will now
     raise an exception on such an access so that you can at least find
     out about the problem.  See
     ‘https://mail.python.org/pipermail/python-dev/2002-December/031107.html’
     for a more detailed explanation of this change.  (Implemented by
     Martin von Löwis.)

   * Calling Tcl methods through ‘_tkinter’ no longer returns only
     strings.  Instead, if Tcl returns other objects those objects are
     converted to their Python equivalent, if one exists, or wrapped
     with a ‘_tkinter.Tcl_Obj’ object if no Python equivalent exists.
     This behavior can be controlled through the ‘wantobjects()’ method
     of ‘tkapp’ objects.

     When using ‘_tkinter’ through the ‘Tkinter’ module (as most Tkinter
     applications will), this feature is always activated.  It should
     not cause compatibility problems, since Tkinter would always
     convert string results to Python types where possible.

     If any incompatibilities are found, the old behavior can be
     restored by setting the ‘wantobjects’ variable in the ‘Tkinter’
     module to false before creating the first ‘tkapp’ object.

          import Tkinter
          Tkinter.wantobjects = 0

     Any breakage caused by this change should be reported as a bug.

   * The ‘UserDict’ module has a new ‘DictMixin’ class which defines all
     dictionary methods for classes that already have a minimum mapping
     interface.  This greatly simplifies writing classes that need to be
     substitutable for dictionaries, such as the classes in the *note
     shelve: c3. module.

     Adding the mix-in as a superclass provides the full dictionary
     interface whenever the class defines *note __getitem__(): 283,
     *note __setitem__(): 1313, *note __delitem__(): 1314, and ‘keys()’.
     For example:

          >>> import UserDict
          >>> class SeqDict(UserDict.DictMixin):
          ...     """Dictionary lookalike implemented with lists."""
          ...     def __init__(self):
          ...         self.keylist = []
          ...         self.valuelist = []
          ...     def __getitem__(self, key):
          ...         try:
          ...             i = self.keylist.index(key)
          ...         except ValueError:
          ...             raise KeyError
          ...         return self.valuelist[i]
          ...     def __setitem__(self, key, value):
          ...         try:
          ...             i = self.keylist.index(key)
          ...             self.valuelist[i] = value
          ...         except ValueError:
          ...             self.keylist.append(key)
          ...             self.valuelist.append(value)
          ...     def __delitem__(self, key):
          ...         try:
          ...             i = self.keylist.index(key)
          ...         except ValueError:
          ...             raise KeyError
          ...         self.keylist.pop(i)
          ...         self.valuelist.pop(i)
          ...     def keys(self):
          ...         return list(self.keylist)
          ...
          >>> s = SeqDict()
          >>> dir(s)      # See that other dictionary methods are implemented
          ['__cmp__', '__contains__', '__delitem__', '__doc__', '__getitem__',
           '__init__', '__iter__', '__len__', '__module__', '__repr__',
           '__setitem__', 'clear', 'get', 'has_key', 'items', 'iteritems',
           'iterkeys', 'itervalues', 'keylist', 'keys', 'pop', 'popitem',
           'setdefault', 'update', 'valuelist', 'values']

     (Contributed by Raymond Hettinger.)

   * The DOM implementation in *note xml.dom.minidom: 122. can now
     generate XML output in a particular encoding by providing an
     optional encoding argument to the *note toxml(): aa8. and *note
     toprettyxml(): aa9. methods of DOM nodes.

   * The ‘xmlrpclib’ module now supports an XML-RPC extension for
     handling nil data values such as Python’s ‘None’.  Nil values are
     always supported on unmarshalling an XML-RPC response.  To generate
     requests containing ‘None’, you must supply a true value for the
     'allow_none' parameter when creating a ‘Marshaller’ instance.

   * The new ‘DocXMLRPCServer’ module allows writing self-documenting
     XML-RPC servers.  Run it in demo mode (as a program) to see it in
     action.  Pointing the web browser to the RPC server produces
     pydoc-style documentation; pointing xmlrpclib to the server allows
     invoking the actual methods.  (Contributed by Brian Quinlan.)

   * Support for internationalized domain names (RFCs 3454, 3490, 3491,
     and 3492) has been added.  The “idna” encoding can be used to
     convert between a Unicode domain name and the ASCII-compatible
     encoding (ACE) of that name.

          >{}>{}> u"www.Alliancefrançaise.nu".encode("idna")
          'www.xn--alliancefranaise-npb.nu'

     The *note socket: cc. module has also been extended to
     transparently convert Unicode hostnames to the ACE version before
     passing them to the C library.  Modules that deal with hostnames
     such as ‘httplib’ and *note ftplib: 5e.) also support Unicode host
     names; ‘httplib’ also sends HTTP ‘Host’ headers using the ACE
     version of the domain name.  *note urllib: 108. supports Unicode
     URLs with non-ASCII host names as long as the ‘path’ part of the
     URL is ASCII only.

     To implement this change, the *note stringprep: d4. module, the
     ‘mkstringprep’ tool and the ‘punycode’ encoding have been added.

* Menu:

* Date/Time Type::
* The optparse Module::

   ---------- Footnotes ----------

   (1) https://pybsddb.sourceforge.net


File: python.info,  Node: Date/Time Type,  Next: The optparse Module,  Up: New Improved and Deprecated Modules<4>

1.19.17.1 Date/Time Type
........................

Date and time types suitable for expressing timestamps were added as the
*note datetime: 30. module.  The types don’t support different calendars
or many fancy features, and just stick to the basics of representing
time.

The three primary types are: *note date: 1cd, representing a day, month,
and year; *note time: 1ce, consisting of hour, minute, and second; and
*note datetime: 1cc, which contains all the attributes of both ‘date’
and ‘time’.  There’s also a *note timedelta: 9da. class representing
differences between two points in time, and time zone logic is
implemented by classes inheriting from the abstract *note tzinfo: 5e1.
class.

You can create instances of *note date: 1cd. and *note time: 1ce. by
either supplying keyword arguments to the appropriate constructor, e.g.
‘datetime.date(year=1972, month=10, day=15)’, or by using one of a
number of class methods.  For example, the *note today(): 1519. class
method returns the current local date.

Once created, instances of the date/time classes are all immutable.
There are a number of methods for producing formatted strings from
objects:

     >>> import datetime as dt
     >>> now = dt.datetime.now()
     >>> now.isoformat()
     '2002-12-30T21:27:03.994956'
     >>> now.ctime()  # Only available on date, datetime
     'Mon Dec 30 21:27:03 2002'
     >>> now.strftime('%Y %d %b')
     '2002 30 Dec'

The *note replace(): 151a. method allows modifying one or more fields of
a *note date: 1cd. or *note datetime: 1cc. instance, returning a new
instance:

     >>> d = dt.datetime.now()
     >>> d
     datetime.datetime(2002, 12, 30, 22, 15, 38, 827738)
     >>> d.replace(year=2001, hour=12)
     datetime.datetime(2001, 12, 30, 12, 15, 38, 827738)
     >>>

Instances can be compared, hashed, and converted to strings (the result
is the same as that of *note isoformat(): b48.).  *note date: 1cd. and
*note datetime: 1cc. instances can be subtracted from each other, and
added to *note timedelta: 9da. instances.  The largest missing feature
is that there’s no standard library support for parsing strings and
getting back a ‘date’ or ‘datetime’.

For more information, refer to the module’s reference documentation.
(Contributed by Tim Peters.)


File: python.info,  Node: The optparse Module,  Prev: Date/Time Type,  Up: New Improved and Deprecated Modules<4>

1.19.17.2 The optparse Module
.............................

The *note getopt: 61. module provides simple parsing of command-line
arguments.  The new *note optparse: a0. module (originally named Optik)
provides more elaborate command-line parsing that follows the Unix
conventions, automatically creates the output for ‘--help’, and can
perform different actions for different options.

You start by creating an instance of *note OptionParser: 151c. and
telling it what your program’s options are.

     import sys
     from optparse import OptionParser

     op = OptionParser()
     op.add_option('-i', '--input',
                   action='store', type='string', dest='input',
                   help='set input filename')
     op.add_option('-l', '--length',
                   action='store', type='int', dest='length',
                   help='set maximum length of output')

Parsing a command line is then done by calling the *note parse_args():
151d. method.

     options, args = op.parse_args(sys.argv[1:])
     print options
     print args

This returns an object containing all of the option values, and a list
of strings containing the remaining arguments.

Invoking the script with the various arguments now works as you’d expect
it to.  Note that the length argument is automatically converted to an
integer.

     $ ./python opt.py -i data arg1
     <Values at 0x400cad4c: {'input': 'data', 'length': None}>
     ['arg1']
     $ ./python opt.py --input=data --length=4
     <Values at 0x400cad2c: {'input': 'data', 'length': 4}>
     []
     $

The help message is automatically generated for you:

     $ ./python opt.py --help
     usage: opt.py [options]

     options:
       -h, --help            show this help message and exit
       -iINPUT, --input=INPUT
                             set input filename
       -lLENGTH, --length=LENGTH
                             set maximum length of output
     $

See the module’s documentation for more details.

Optik was written by Greg Ward, with suggestions from the readers of the
Getopt SIG.


File: python.info,  Node: Pymalloc A Specialized Object Allocator,  Next: Build and C API Changes<12>,  Prev: New Improved and Deprecated Modules<4>,  Up: What’s New in Python 2 3

1.19.18 Pymalloc: A Specialized Object Allocator
------------------------------------------------

Pymalloc, a specialized object allocator written by Vladimir Marangozov,
was a feature added to Python 2.1.  Pymalloc is intended to be faster
than the system ‘malloc()’ and to have less memory overhead for
allocation patterns typical of Python programs.  The allocator uses C’s
‘malloc()’ function to get large pools of memory and then fulfills
smaller memory requests from these pools.

In 2.1 and 2.2, pymalloc was an experimental feature and wasn’t enabled
by default; you had to explicitly enable it when compiling Python by
providing the ‘--with-pymalloc’ option to the ‘configure’ script.  In
2.3, pymalloc has had further enhancements and is now enabled by
default; you’ll have to supply ‘--without-pymalloc’ to disable it.

This change is transparent to code written in Python; however, pymalloc
may expose bugs in C extensions.  Authors of C extension modules should
test their code with pymalloc enabled, because some incorrect code may
cause core dumps at runtime.

There’s one particularly common error that causes problems.  There are a
number of memory allocation functions in Python’s C API that have
previously just been aliases for the C library’s ‘malloc()’ and
‘free()’, meaning that if you accidentally called mismatched functions
the error wouldn’t be noticeable.  When the object allocator is enabled,
these functions aren’t aliases of ‘malloc()’ and ‘free()’ any more, and
calling the wrong function to free memory may get you a core dump.  For
example, if memory was allocated using *note PyObject_Malloc(): c89, it
has to be freed using *note PyObject_Free(): c86, not ‘free()’.  A few
modules included with Python fell afoul of this and had to be fixed;
doubtless there are more third-party modules that will have the same
problem.

As part of this change, the confusing multiple interfaces for allocating
memory have been consolidated down into two API families.  Memory
allocated with one family must not be manipulated with functions from
the other family.  There is one family for allocating chunks of memory
and another family of functions specifically for allocating Python
objects.

   * To allocate and free an undistinguished chunk of memory use the
     “raw memory” family: *note PyMem_Malloc(): c87, *note
     PyMem_Realloc(): 106f, and *note PyMem_Free(): 1491.

   * The “object memory” family is the interface to the pymalloc
     facility described above and is biased towards a large number of
     “small” allocations: *note PyObject_Malloc(): c89, *note
     PyObject_Realloc(): 1492, and *note PyObject_Free(): c86.

   * To allocate and free Python objects, use the “object” family *note
     PyObject_New: 98f, *note PyObject_NewVar: 990, and *note
     PyObject_Del(): 1520.

Thanks to lots of work by Tim Peters, pymalloc in 2.3 also provides
debugging features to catch memory overwrites and doubled frees in both
extension modules and in the interpreter itself.  To enable this
support, compile a debugging version of the Python interpreter by
running ‘configure’ with ‘--with-pydebug’.

To aid extension writers, a header file ‘Misc/pymemcompat.h’ is
distributed with the source to Python 2.3 that allows Python extensions
to use the 2.3 interfaces to memory allocation while compiling against
any version of Python since 1.5.2.  You would copy the file from
Python’s source distribution and bundle it with the source of your
extension.

See also
........

‘https://hg.python.org/cpython/file/default/Objects/obmalloc.c’

     For the full details of the pymalloc implementation, see the
     comments at the top of the file ‘Objects/obmalloc.c’ in the Python
     source code.  The above link points to the file within the
     python.org SVN browser.


File: python.info,  Node: Build and C API Changes<12>,  Next: Other Changes and Fixes<2>,  Prev: Pymalloc A Specialized Object Allocator,  Up: What’s New in Python 2 3

1.19.19 Build and C API Changes
-------------------------------

Changes to Python’s build process and to the C API include:

   * The cycle detection implementation used by the garbage collection
     has proven to be stable, so it’s now been made mandatory.  You can
     no longer compile Python without it, and the ‘--with-cycle-gc’
     switch to ‘configure’ has been removed.

   * Python can now optionally be built as a shared library
     (‘libpython2.3.so’) by supplying ‘--enable-shared’ when running
     Python’s ‘configure’ script.  (Contributed by Ondrej Palkovsky.)

   * The ‘DL_EXPORT’ and ‘DL_IMPORT’ macros are now deprecated.
     Initialization functions for Python extension modules should now be
     declared using the new macro *note PyMODINIT_FUNC: 1522, while the
     Python core will generally use the ‘PyAPI_FUNC’ and ‘PyAPI_DATA’
     macros.

   * The interpreter can be compiled without any docstrings for the
     built-in functions and modules by supplying ‘--without-doc-strings’
     to the ‘configure’ script.  This makes the Python executable about
     10% smaller, but will also mean that you can’t get help for
     Python’s built-ins.  (Contributed by Gustavo Niemeyer.)

   * The ‘PyArg_NoArgs()’ macro is now deprecated, and code that uses it
     should be changed.  For Python 2.2 and later, the method definition
     table can specify the *note METH_NOARGS: 1523. flag, signalling
     that there are no arguments, and the argument checking can then be
     removed.  If compatibility with pre-2.2 versions of Python is
     important, the code could use ‘PyArg_ParseTuple(args, "")’ instead,
     but this will be slower than using ‘METH_NOARGS’.

   * *note PyArg_ParseTuple(): 574. accepts new format characters for
     various sizes of unsigned integers: ‘B’ for unsigned char, ‘H’ for
     unsigned short int, ‘I’ for unsigned int, and ‘K’ for unsigned long
     long.

   * A new function, ‘PyObject_DelItemString(mapping, char *key)’ was
     added as shorthand for ‘PyObject_DelItem(mapping,
     PyString_New(key))’.

   * File objects now manage their internal string buffer differently,
     increasing it exponentially when needed.  This results in the
     benchmark tests in ‘Lib/test/test_bufio.py’ speeding up
     considerably (from 57 seconds to 1.7 seconds, according to one
     measurement).

   * It’s now possible to define class and static methods for a C
     extension type by setting either the *note METH_CLASS: 1524. or
     *note METH_STATIC: 1525. flags in a method’s *note PyMethodDef:
     1526. structure.

   * Python now includes a copy of the Expat XML parser’s source code,
     removing any dependence on a system version or local installation
     of Expat.

   * If you dynamically allocate type objects in your extension, you
     should be aware of a change in the rules relating to the *note
     __module__: 377. and *note __name__: 14fa. attributes.  In summary,
     you will want to ensure the type’s dictionary contains a
     ‘'__module__'’ key; making the module name the part of the type
     name leading up to the final period will no longer have the desired
     effect.  For more detail, read the API reference documentation or
     the source.

* Menu:

* Port-Specific Changes: Port-Specific Changes<3>.


File: python.info,  Node: Port-Specific Changes<3>,  Up: Build and C API Changes<12>

1.19.19.1 Port-Specific Changes
...............................

Support for a port to IBM’s OS/2 using the EMX runtime environment was
merged into the main Python source tree.  EMX is a POSIX emulation layer
over the OS/2 system APIs.  The Python port for EMX tries to support all
the POSIX-like capability exposed by the EMX runtime, and mostly
succeeds; ‘fork()’ and *note fcntl(): 59. are restricted by the
limitations of the underlying emulation layer.  The standard OS/2 port,
which uses IBM’s Visual Age compiler, also gained support for
case-sensitive import semantics as part of the integration of the EMX
port into CVS. (Contributed by Andrew MacIntyre.)

On MacOS, most toolbox modules have been weaklinked to improve backward
compatibility.  This means that modules will no longer fail to load if a
single routine is missing on the current OS version.  Instead calling
the missing routine will raise an exception.  (Contributed by Jack
Jansen.)

The RPM spec files, found in the ‘Misc/RPM/’ directory in the Python
source distribution, were updated for 2.3.  (Contributed by Sean
Reifschneider.)

Other new platforms now supported by Python include AtheOS
(‘http://www.atheos.cx/’), GNU/Hurd, and OpenVMS.


File: python.info,  Node: Other Changes and Fixes<2>,  Next: Porting to Python 2 3,  Prev: Build and C API Changes<12>,  Up: What’s New in Python 2 3

1.19.20 Other Changes and Fixes
-------------------------------

As usual, there were a bunch of other improvements and bugfixes
scattered throughout the source tree.  A search through the CVS change
logs finds there were 523 patches applied and 514 bugs fixed between
Python 2.2 and 2.3.  Both figures are likely to be underestimates.

Some of the more notable changes are:

   * If the *note PYTHONINSPECT: 1529. environment variable is set, the
     Python interpreter will enter the interactive prompt after running
     a Python program, as if Python had been invoked with the *note -i:
     152a. option.  The environment variable can be set before running
     the Python interpreter, or it can be set by the Python program as
     part of its execution.

   * The ‘regrtest.py’ script now provides a way to allow “all resources
     except 'foo'.” A resource name passed to the ‘-u’ option can now be
     prefixed with a hyphen (‘'-'’) to mean “remove this resource.” For
     example, the option ‘‘-uall,-bsddb’’ could be used to enable the
     use of all resources except ‘bsddb’.

   * The tools used to build the documentation now work under Cygwin as
     well as Unix.

   * The ‘SET_LINENO’ opcode has been removed.  Back in the mists of
     time, this opcode was needed to produce line numbers in tracebacks
     and support trace functions (for, e.g., *note pdb: a5.).  Since
     Python 1.5, the line numbers in tracebacks have been computed using
     a different mechanism that works with “python -O”.  For Python 2.3
     Michael Hudson implemented a similar scheme to determine when to
     call the trace function, removing the need for ‘SET_LINENO’
     entirely.

     It would be difficult to detect any resulting difference from
     Python code, apart from a slight speed up when Python is run
     without *note -O: de3.

     C extensions that access the *note f_lineno: 7b0. field of frame
     objects should instead call ‘PyCode_Addr2Line(f->f_code,
     f->f_lasti)’.  This will have the added effect of making the code
     work as desired under “python -O” in earlier versions of Python.

     A nifty new feature is that trace functions can now assign to the
     *note f_lineno: 7b0. attribute of frame objects, changing the line
     that will be executed next.  A ‘jump’ command has been added to the
     *note pdb: a5. debugger taking advantage of this new feature.
     (Implemented by Richie Hindle.)


File: python.info,  Node: Porting to Python 2 3,  Next: Acknowledgements<5>,  Prev: Other Changes and Fixes<2>,  Up: What’s New in Python 2 3

1.19.21 Porting to Python 2.3
-----------------------------

This section lists previously described changes that may require changes
to your code:

   * *note yield: 9d8. is now always a keyword; if it’s used as a
     variable name in your code, a different name must be chosen.

   * For strings 'X' and 'Y', ‘X in Y’ now works if 'X' is more than one
     character long.

   * The *note int(): 257. type constructor will now return a long
     integer instead of raising an *note OverflowError: 888. when a
     string or floating-point number is too large to fit into an
     integer.

   * If you have Unicode strings that contain 8-bit characters, you must
     declare the file’s encoding (UTF-8, Latin-1, or whatever) by adding
     a comment to the top of the file.  See section *note PEP 263;
     Source Code Encodings: 14d9. for more information.

   * Calling Tcl methods through ‘_tkinter’ no longer returns only
     strings.  Instead, if Tcl returns other objects those objects are
     converted to their Python equivalent, if one exists, or wrapped
     with a ‘_tkinter.Tcl_Obj’ object if no Python equivalent exists.

   * Large octal and hex literals such as ‘0xffffffff’ now trigger a
     *note FutureWarning: 418.  Currently they’re stored as 32-bit
     numbers and result in a negative value, but in Python 2.4 they’ll
     become positive long integers.

     There are a few ways to fix this warning.  If you really need a
     positive number, just add an ‘L’ to the end of the literal.  If
     you’re trying to get a 32-bit integer with low bits set and have
     previously used an expression such as ‘~(1 << 31)’, it’s probably
     clearest to start with all bits set and clear the desired upper
     bits.  For example, to clear just the top bit (bit 31), you could
     write ‘0xffffffffL &~(1L<<31)’.

   * You can no longer disable assertions by assigning to ‘__debug__’.

   * The Distutils ‘setup()’ function has gained various new keyword
     arguments such as 'depends'.  Old versions of the Distutils will
     abort if passed unknown keywords.  A solution is to check for the
     presence of the new ‘get_distutil_options()’ function in your
     ‘setup.py’ and only uses the new keywords with a version of the
     Distutils that supports them:

          from distutils import core

          kw = {'sources': 'foo.c', ...}
          if hasattr(core, 'get_distutil_options'):
              kw['depends'] = ['foo.h']
          ext = Extension(**kw)

   * Using ‘None’ as a variable name will now result in a *note
     SyntaxWarning: 469. warning.

   * Names of extension types defined by the modules included with
     Python now contain the module and a ‘'.'’ in front of the type
     name.


File: python.info,  Node: Acknowledgements<5>,  Prev: Porting to Python 2 3,  Up: What’s New in Python 2 3

1.19.22 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Jeff Bauer, Simon Brunning, Brett Cannon, Michael Chermside,
Andrew Dalke, Scott David Daniels, Fred L. Drake, Jr., David Fraser,
Kelly Gerber, Raymond Hettinger, Michael Hudson, Chris Lambert, Detlef
Lannert, Martin von Löwis, Andrew MacIntyre, Lalo Martins, Chad Netzer,
Gustavo Niemeyer, Neal Norwitz, Hans Nowak, Chris Reedy, Francesco
Ricciardi, Vinay Sajip, Neil Schemenauer, Roman Suzi, Jason Tishler,
Just van Rossum.


File: python.info,  Node: What’s New in Python 2 2,  Next: What’s New in Python 2 1,  Prev: What’s New in Python 2 3,  Up: What’s New in Python

1.20 What’s New in Python 2.2
=============================


Author: A.M. Kuchling

* Menu:

* Introduction::
* PEPs 252 and 253; Type and Class Changes: PEPs 252 and 253 Type and Class Changes.
* PEP 234; Iterators: PEP 234 Iterators.
* PEP 255; Simple Generators: PEP 255 Simple Generators<2>.
* PEP 237; Unifying Long Integers and Integers: PEP 237 Unifying Long Integers and Integers<2>.
* PEP 238; Changing the Division Operator: PEP 238 Changing the Division Operator.
* Unicode Changes::
* PEP 227; Nested Scopes: PEP 227 Nested Scopes.
* New and Improved Modules: New and Improved Modules<3>.
* Interpreter Changes and Fixes::
* Other Changes and Fixes: Other Changes and Fixes<3>.
* Acknowledgements: Acknowledgements<6>.


File: python.info,  Node: Introduction,  Next: PEPs 252 and 253 Type and Class Changes,  Up: What’s New in Python 2 2

1.20.1 Introduction
-------------------

This article explains the new features in Python 2.2.2, released on
October 14, 2002.  Python 2.2.2 is a bugfix release of Python 2.2,
originally released on December 21, 2001.

Python 2.2 can be thought of as the “cleanup release”.  There are some
features such as generators and iterators that are completely new, but
most of the changes, significant and far-reaching though they may be,
are aimed at cleaning up irregularities and dark corners of the language
design.

This article doesn’t attempt to provide a complete specification of the
new features, but instead provides a convenient overview.  For full
details, you should refer to the documentation for Python 2.2, such as
the Python Library Reference(1) and the Python Reference Manual(2).  If
you want to understand the complete implementation and design rationale
for a change, refer to the PEP for a particular new feature.

   ---------- Footnotes ----------

   (1) https://docs.python.org/2.2/lib/lib.html

   (2) https://docs.python.org/2.2/ref/ref.html


File: python.info,  Node: PEPs 252 and 253 Type and Class Changes,  Next: PEP 234 Iterators,  Prev: Introduction,  Up: What’s New in Python 2 2

1.20.2 PEPs 252 and 253: Type and Class Changes
-----------------------------------------------

The largest and most far-reaching changes in Python 2.2 are to Python’s
model of objects and classes.  The changes should be backward
compatible, so it’s likely that your code will continue to run
unchanged, but the changes provide some amazing new capabilities.
Before beginning this, the longest and most complicated section of this
article, I’ll provide an overview of the changes and offer some
comments.

A long time ago I wrote a web page listing flaws in Python’s design.
One of the most significant flaws was that it’s impossible to subclass
Python types implemented in C. In particular, it’s not possible to
subclass built-in types, so you can’t just subclass, say, lists in order
to add a single useful method to them.  The ‘UserList’ module provides a
class that supports all of the methods of lists and that can be
subclassed further, but there’s lots of C code that expects a regular
Python list and won’t accept a *note UserList: 1533. instance.

Python 2.2 fixes this, and in the process adds some exciting new
capabilities.  A brief summary:

   * You can subclass built-in types such as lists and even integers,
     and your subclasses should work in every place that requires the
     original type.

   * It’s now possible to define static and class methods, in addition
     to the instance methods available in previous versions of Python.

   * It’s also possible to automatically call methods on accessing or
     setting an instance attribute by using a new mechanism called
     'properties'.  Many uses of *note __getattr__(): 4d6. can be
     rewritten to use properties instead, making the resulting code
     simpler and faster.  As a small side benefit, attributes can now
     have docstrings, too.

   * The list of legal attributes for an instance can be limited to a
     particular set using 'slots', making it possible to safeguard
     against typos and perhaps make more optimizations possible in
     future versions of Python.

Some users have voiced concern about all these changes.  Sure, they say,
the new features are neat and lend themselves to all sorts of tricks
that weren’t possible in previous versions of Python, but they also make
the language more complicated.  Some people have said that they’ve
always recommended Python for its simplicity, and feel that its
simplicity is being lost.

Personally, I think there’s no need to worry.  Many of the new features
are quite esoteric, and you can write a lot of Python code without ever
needed to be aware of them.  Writing a simple class is no more difficult
than it ever was, so you don’t need to bother learning or teaching them
unless they’re actually needed.  Some very complicated tasks that were
previously only possible from C will now be possible in pure Python, and
to my mind that’s all for the better.

I’m not going to attempt to cover every single corner case and small
change that were required to make the new features work.  Instead this
section will paint only the broad strokes.  See section *note Related
Links: 1534, “Related Links”, for further sources of information about
Python 2.2’s new object model.

* Menu:

* Old and New Classes::
* Descriptors::
* Multiple Inheritance; The Diamond Rule: Multiple Inheritance The Diamond Rule.
* Attribute Access::
* Related Links::


File: python.info,  Node: Old and New Classes,  Next: Descriptors,  Up: PEPs 252 and 253 Type and Class Changes

1.20.2.1 Old and New Classes
............................

First, you should know that Python 2.2 really has two kinds of classes:
classic or old-style classes, and new-style classes.  The old-style
class model is exactly the same as the class model in earlier versions
of Python.  All the new features described in this section apply only to
new-style classes.  This divergence isn’t intended to last forever;
eventually old-style classes will be dropped, possibly in Python 3.0.

So how do you define a new-style class?  You do it by subclassing an
existing new-style class.  Most of Python’s built-in types, such as
integers, lists, dictionaries, and even files, are new-style classes
now.  A new-style class named *note object: a9b, the base class for all
built-in types, has also been added so if no built-in type is suitable,
you can just subclass ‘object’:

     class C(object):
         def __init__ (self):
             ...
         ...

This means that *note class: 131f. statements that don’t have any base
classes are always classic classes in Python 2.2.  (Actually you can
also change this by setting a module-level variable named
‘__metaclass__’ — see PEP 253(1) for the details — but it’s easier to
just subclass *note object: a9b.)

The type objects for the built-in types are available as built-ins,
named using a clever trick.  Python has always had built-in functions
named *note int(): 257, *note float(): 2f7, and *note str(): 44f.  In
2.2, they aren’t functions any more, but type objects that behave as
factories when called.

     >>> int
     <type 'int'>
     >>> int('123')
     123

To make the set of types complete, new type objects such as *note
dict(): 256. and ‘file()’ have been added.  Here’s a more interesting
example, adding a ‘lock()’ method to file objects:

     class LockableFile(file):
         def lock (self, operation, length=0, start=0, whence=0):
             import fcntl
             return fcntl.lockf(self.fileno(), operation,
                                length, start, whence)

The now-obsolete ‘posixfile’ module contained a class that emulated all
of a file object’s methods and also added a ‘lock()’ method, but this
class couldn’t be passed to internal functions that expected a built-in
file, something which is possible with our new ‘LockableFile’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0253/


File: python.info,  Node: Descriptors,  Next: Multiple Inheritance The Diamond Rule,  Prev: Old and New Classes,  Up: PEPs 252 and 253 Type and Class Changes

1.20.2.2 Descriptors
....................

In previous versions of Python, there was no consistent way to discover
what attributes and methods were supported by an object.  There were
some informal conventions, such as defining ‘__members__’ and
‘__methods__’ attributes that were lists of names, but often the author
of an extension type or a class wouldn’t bother to define them.  You
could fall back on inspecting the *note __dict__: 55e. of an object, but
when class inheritance or an arbitrary ‘__getattr__()’ hook were in use
this could still be inaccurate.

The one big idea underlying the new class model is that an API for
describing the attributes of an object using 'descriptors' has been
formalized.  Descriptors specify the value of an attribute, stating
whether it’s a method or a field.  With the descriptor API, static
methods and class methods become possible, as well as more exotic
constructs.

Attribute descriptors are objects that live inside class objects, and
have a few attributes of their own:

   * *note __name__: 10a4. is the attribute’s name.

   * *note __doc__: 931. is the attribute’s docstring.

   * ‘__get__(object)’ is a method that retrieves the attribute value
     from 'object'.

   * ‘__set__(object, value)’ sets the attribute on 'object' to 'value'.

   * ‘__delete__(object, value)’ deletes the 'value' attribute of
     'object'.

For example, when you write ‘obj.x’, the steps that Python actually
performs are:

     descriptor = obj.__class__.x
     descriptor.__get__(obj)

For methods, *note descriptor.__get__: 1537. returns a temporary object
that’s callable, and wraps up the instance and the method to be called
on it.  This is also why static methods and class methods are now
possible; they have descriptors that wrap up just the method, or the
method and the class.  As a brief explanation of these new kinds of
methods, static methods aren’t passed the instance, and therefore
resemble regular functions.  Class methods are passed the class of the
object, but not the object itself.  Static and class methods are defined
like this:

     class C(object):
         def f(arg1, arg2):
             ...
         f = staticmethod(f)

         def g(cls, arg1, arg2):
             ...
         g = classmethod(g)

The *note staticmethod(): 419. function takes the function ‘f()’, and
returns it wrapped up in a descriptor so it can be stored in the class
object.  You might expect there to be special syntax for creating such
methods (‘def static f’, ‘defstatic f()’, or something like that) but no
such syntax has been defined yet; that’s been left for future versions
of Python.

More new features, such as slots and properties, are also implemented as
new kinds of descriptors, and it’s not difficult to write a descriptor
class that does something novel.  For example, it would be possible to
write a descriptor class that made it possible to write Eiffel-style
preconditions and postconditions for a method.  A class that used this
feature might be defined like this:

     from eiffel import eiffelmethod

     class C(object):
         def f(self, arg1, arg2):
             # The actual function
             ...
         def pre_f(self):
             # Check preconditions
             ...
         def post_f(self):
             # Check postconditions
             ...

         f = eiffelmethod(f, pre_f, post_f)

Note that a person using the new ‘eiffelmethod()’ doesn’t have to
understand anything about descriptors.  This is why I think the new
features don’t increase the basic complexity of the language.  There
will be a few wizards who need to know about it in order to write
‘eiffelmethod()’ or the ZODB or whatever, but most users will just write
code on top of the resulting libraries and ignore the implementation
details.


File: python.info,  Node: Multiple Inheritance The Diamond Rule,  Next: Attribute Access,  Prev: Descriptors,  Up: PEPs 252 and 253 Type and Class Changes

1.20.2.3 Multiple Inheritance: The Diamond Rule
...............................................

Multiple inheritance has also been made more useful through changing the
rules under which names are resolved.  Consider this set of classes
(diagram taken from PEP 253(1) by Guido van Rossum):

           class A:
             ^ ^  def save(self): ...
            /   \
           /     \
          /       \
         /         \
     class B     class C:
         ^         ^  def save(self): ...
          \       /
           \     /
            \   /
             \ /
           class D

The lookup rule for classic classes is simple but not very smart; the
base classes are searched depth-first, going from left to right.  A
reference to ‘D.save()’ will search the classes ‘D’, ‘B’, and then ‘A’,
where ‘save()’ would be found and returned.  ‘C.save()’ would never be
found at all.  This is bad, because if ‘C’’s ‘save()’ method is saving
some internal state specific to ‘C’, not calling it will result in that
state never getting saved.

New-style classes follow a different algorithm that’s a bit more
complicated to explain, but does the right thing in this situation.
(Note that Python 2.3 changes this algorithm to one that produces the
same results in most cases, but produces more useful results for really
complicated inheritance graphs.)

  1. List all the base classes, following the classic lookup rule and
     include a class multiple times if it’s visited repeatedly.  In the
     above example, the list of visited classes is [‘D’, ‘B’, ‘A’, ‘C’,
     ‘A’].

  2. Scan the list for duplicated classes.  If any are found, remove all
     but one occurrence, leaving the 'last' one in the list.  In the
     above example, the list becomes [‘D’, ‘B’, ‘C’, ‘A’] after dropping
     duplicates.

Following this rule, referring to ‘D.save()’ will return ‘C.save()’,
which is the behaviour we’re after.  This lookup rule is the same as the
one followed by Common Lisp.  A new built-in function, *note super():
4de, provides a way to get at a class’s superclasses without having to
reimplement Python’s algorithm.  The most commonly used form will be
‘super(class, obj)’, which returns a bound superclass object (not the
actual class object).  This form will be used in methods to call a
method in the superclass; for example, ‘D’’s ‘save()’ method would look
like this:

     class D (B,C):
         def save (self):
             # Call superclass .save()
             super(D, self).save()
             # Save D's private information here
             ...

*note super(): 4de. can also return unbound superclass objects when
called as ‘super(class)’ or ‘super(class1, class2)’, but this probably
won’t often be useful.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0253/


File: python.info,  Node: Attribute Access,  Next: Related Links,  Prev: Multiple Inheritance The Diamond Rule,  Up: PEPs 252 and 253 Type and Class Changes

1.20.2.4 Attribute Access
.........................

A fair number of sophisticated Python classes define hooks for attribute
access using *note __getattr__(): 4d6.; most commonly this is done for
convenience, to make code more readable by automatically mapping an
attribute access such as ‘obj.parent’ into a method call such as
‘obj.get_parent’.  Python 2.2 adds some new ways of controlling
attribute access.

First, ‘__getattr__(attr_name)’ is still supported by new-style classes,
and nothing about it has changed.  As before, it will be called when an
attempt is made to access ‘obj.foo’ and no attribute named ‘foo’ is
found in the instance’s dictionary.

New-style classes also support a new method,
‘__getattribute__(attr_name)’.  The difference between the two methods
is that *note __getattribute__(): bf1. is 'always' called whenever any
attribute is accessed, while the old *note __getattr__(): 4d6. is only
called if ‘foo’ isn’t found in the instance’s dictionary.

However, Python 2.2’s support for 'properties' will often be a simpler
way to trap attribute references.  Writing a ‘__getattr__()’ method is
complicated because to avoid recursion you can’t use regular attribute
accesses inside them, and instead have to mess around with the contents
of *note __dict__: 55e.  *note __getattr__(): 4d6. methods also end up
being called by Python when it checks for other methods such as *note
__repr__(): 61f. or ‘__coerce__()’, and so have to be written with this
in mind.  Finally, calling a function on every attribute access results
in a sizable performance loss.

*note property: 194. is a new built-in type that packages up three
functions that get, set, or delete an attribute, and a docstring.  For
example, if you want to define a ‘size’ attribute that’s computed, but
also settable, you could write:

     class C(object):
         def get_size (self):
             result = ... computation ...
             return result
         def set_size (self, size):
             ... compute something based on the size
             and set internal state appropriately ...

         # Define a property.  The 'delete this attribute'
         # method is defined as None, so the attribute
         # can't be deleted.
         size = property(get_size, set_size,
                         None,
                         "Storage size of this instance")

That is certainly clearer and easier to write than a pair of
‘__getattr__()’/‘__setattr__()’ methods that check for the ‘size’
attribute and handle it specially while retrieving all other attributes
from the instance’s *note __dict__: 55e.  Accesses to ‘size’ are also
the only ones which have to perform the work of calling a function, so
references to other attributes run at their usual speed.

Finally, it’s possible to constrain the list of attributes that can be
referenced on an object using the new *note __slots__: 153a. class
attribute.  Python objects are usually very dynamic; at any time it’s
possible to define a new attribute on an instance by just doing
‘obj.new_attr=1’.  A new-style class can define a class attribute named
‘__slots__’ to limit the legal attributes to a particular set of names.
An example will make this clear:

     >>> class C(object):
     ...     __slots__ = ('template', 'name')
     ...
     >>> obj = C()
     >>> print obj.template
     None
     >>> obj.template = 'Test'
     >>> print obj.template
     Test
     >>> obj.newattr = None
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     AttributeError: 'C' object has no attribute 'newattr'

Note how you get an *note AttributeError: 34e. on the attempt to assign
to an attribute not listed in *note __slots__: 153a.


File: python.info,  Node: Related Links,  Prev: Attribute Access,  Up: PEPs 252 and 253 Type and Class Changes

1.20.2.5 Related Links
......................

This section has just been a quick overview of the new features, giving
enough of an explanation to start you programming, but many details have
been simplified or ignored.  Where should you go to get a more complete
picture?

The *note Descriptor Guide: 153c. is a lengthy tutorial introduction to
the descriptor features, written by Guido van Rossum.  If my description
has whetted your appetite, go read this tutorial next, because it goes
into much more detail about the new features while still remaining quite
easy to read.

Next, there are two relevant PEPs, PEP 252(1) and PEP 253(2).  PEP
252(3) is titled “Making Types Look More Like Classes”, and covers the
descriptor API. PEP 253(4) is titled “Subtyping Built-in Types”, and
describes the changes to type objects that make it possible to subtype
built-in objects.  PEP 253(5) is the more complicated PEP of the two,
and at a few points the necessary explanations of types and meta-types
may cause your head to explode.  Both PEPs were written and implemented
by Guido van Rossum, with substantial assistance from the rest of the
Zope Corp.  team.

Finally, there’s the ultimate authority: the source code.  Most of the
machinery for the type handling is in ‘Objects/typeobject.c’, but you
should only resort to it after all other avenues have been exhausted,
including posting a question to python-list or python-dev.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0252/

   (2) https://peps.python.org/pep-0253/

   (3) https://peps.python.org/pep-0252/

   (4) https://peps.python.org/pep-0253/

   (5) https://peps.python.org/pep-0253/


File: python.info,  Node: PEP 234 Iterators,  Next: PEP 255 Simple Generators<2>,  Prev: PEPs 252 and 253 Type and Class Changes,  Up: What’s New in Python 2 2

1.20.3 PEP 234: Iterators
-------------------------

Another significant addition to 2.2 is an iteration interface at both
the C and Python levels.  Objects can define how they can be looped over
by callers.

In Python versions up to 2.1, the usual way to make ‘for item in obj’
work is to define a *note __getitem__(): 283. method that looks
something like this:

     def __getitem__(self, index):
         return <next item>

*note __getitem__(): 283. is more properly used to define an indexing
operation on an object so that you can write ‘obj[5]’ to retrieve the
sixth element.  It’s a bit misleading when you’re using this only to
support *note for: 2f2. loops.  Consider some file-like object that
wants to be looped over; the 'index' parameter is essentially
meaningless, as the class probably assumes that a series of
‘__getitem__()’ calls will be made with 'index' incrementing by one each
time.  In other words, the presence of the ‘__getitem__()’ method
doesn’t mean that using ‘file[5]’ to randomly access the sixth element
will work, though it really should.

In Python 2.2, iteration can be implemented separately, and *note
__getitem__(): 283. methods can be limited to classes that really do
support random access.  The basic idea of iterators is simple.  A new
built-in function, ‘iter(obj)’ or ‘iter(C, sentinel)’, is used to get an
iterator.  ‘iter(obj)’ returns an iterator for the object 'obj', while
‘iter(C, sentinel)’ returns an iterator that will invoke the callable
object 'C' until it returns 'sentinel' to signal that the iterator is
done.

Python classes can define an ‘__iter__()’ method, which should create
and return a new iterator for the object; if the object is its own
iterator, this method can just return ‘self’.  In particular, iterators
will usually be their own iterators.  Extension types implemented in C
can implement a *note tp_iter: 153e. function in order to return an
iterator, and extension types that want to behave as iterators can
define a *note tp_iternext: 153f. function.

So, after all this, what do iterators actually do?  They have one
required method, *note next(): 7dc, which takes no arguments and returns
the next value.  When there are no more values to be returned, calling
‘next()’ should raise the *note StopIteration: c1b. exception.

     >>> L = [1,2,3]
     >>> i = iter(L)
     >>> print i
     <iterator object at 0x8116870>
     >>> i.next()
     1
     >>> i.next()
     2
     >>> i.next()
     3
     >>> i.next()
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     StopIteration
     >>>

In 2.2, Python’s *note for: 2f2. statement no longer expects a sequence;
it expects something for which *note iter(): 7db. will return an
iterator.  For backward compatibility and convenience, an iterator is
automatically constructed for sequences that don’t implement
‘__iter__()’ or a *note tp_iter: 153e. slot, so ‘for i in [1,2,3]’ will
still work.  Wherever the Python interpreter loops over a sequence, it’s
been changed to use the iterator protocol.  This means you can do things
like this:

     >>> L = [1,2,3]
     >>> i = iter(L)
     >>> a,b,c = i
     >>> a,b,c
     (1, 2, 3)

Iterator support has been added to some of Python’s basic types.
Calling *note iter(): 7db. on a dictionary will return an iterator which
loops over its keys:

     >>> m = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
     ...      'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
     >>> for key in m: print key, m[key]
     ...
     Mar 3
     Feb 2
     Aug 8
     Sep 9
     May 5
     Jun 6
     Jul 7
     Jan 1
     Apr 4
     Nov 11
     Dec 12
     Oct 10

That’s just the default behaviour.  If you want to iterate over keys,
values, or key/value pairs, you can explicitly call the ‘iterkeys()’,
‘itervalues()’, or ‘iteritems()’ methods to get an appropriate iterator.
In a minor related change, the *note in: 2f4. operator now works on
dictionaries, so ‘key in dict’ is now equivalent to ‘dict.has_key(key)’.

Files also provide an iterator, which calls the *note readline(): ba.
method until there are no more lines in the file.  This means you can
now read each line of a file using code like this:

     for line in file:
         # do something for each line
         ...

Note that you can only go forward in an iterator; there’s no way to get
the previous element, reset the iterator, or make a copy of it.  An
iterator object could provide such additional capabilities, but the
iterator protocol only requires a *note next(): 7dc. method.

See also
........

PEP 234(1) - Iterators

     Written by Ka-Ping Yee and GvR; implemented by the Python Labs
     crew, mostly by GvR and Tim Peters.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0234/


File: python.info,  Node: PEP 255 Simple Generators<2>,  Next: PEP 237 Unifying Long Integers and Integers<2>,  Prev: PEP 234 Iterators,  Up: What’s New in Python 2 2

1.20.4 PEP 255: Simple Generators
---------------------------------

Generators are another new feature, one that interacts with the
introduction of iterators.

You’re doubtless familiar with how function calls work in Python or C.
When you call a function, it gets a private namespace where its local
variables are created.  When the function reaches a *note return: 9d9.
statement, the local variables are destroyed and the resulting value is
returned to the caller.  A later call to the same function will get a
fresh new set of local variables.  But, what if the local variables
weren’t thrown away on exiting a function?  What if you could later
resume the function where it left off?  This is what generators provide;
they can be thought of as resumable functions.

Here’s the simplest example of a generator function:

     def generate_ints(N):
         for i in range(N):
             yield i

A new keyword, *note yield: 9d8, was introduced for generators.  Any
function containing a ‘yield’ statement is a generator function; this is
detected by Python’s bytecode compiler which compiles the function
specially as a result.  Because a new keyword was introduced, generators
must be explicitly enabled in a module by including a ‘from __future__
import generators’ statement near the top of the module’s source code.
In Python 2.3 this statement will become unnecessary.

When you call a generator function, it doesn’t return a single value;
instead it returns a generator object that supports the iterator
protocol.  On executing the *note yield: 9d8. statement, the generator
outputs the value of ‘i’, similar to a *note return: 9d9. statement.
The big difference between ‘yield’ and a ‘return’ statement is that on
reaching a ‘yield’ the generator’s state of execution is suspended and
local variables are preserved.  On the next call to the generator’s
‘next()’ method, the function will resume executing immediately after
the ‘yield’ statement.  (For complicated reasons, the ‘yield’ statement
isn’t allowed inside the ‘try’ block of a *note try: 6ec.…*note finally:
9d5. statement; read PEP 255(1) for a full explanation of the
interaction between ‘yield’ and exceptions.)

Here’s a sample usage of the ‘generate_ints()’ generator:

     >>> gen = generate_ints(3)
     >>> gen
     <generator object at 0x8117f90>
     >>> gen.next()
     0
     >>> gen.next()
     1
     >>> gen.next()
     2
     >>> gen.next()
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
       File "<stdin>", line 2, in generate_ints
     StopIteration

You could equally write ‘for i in generate_ints(5)’, or ‘a,b,c =
generate_ints(3)’.

Inside a generator function, the *note return: 9d9. statement can only
be used without a value, and signals the end of the procession of
values; afterwards the generator cannot return any further values.
‘return’ with a value, such as ‘return 5’, is a syntax error inside a
generator function.  The end of the generator’s results can also be
indicated by raising *note StopIteration: c1b. manually, or by just
letting the flow of execution fall off the bottom of the function.

You could achieve the effect of generators manually by writing your own
class and storing all the local variables of the generator as instance
variables.  For example, returning a list of integers could be done by
setting ‘self.count’ to 0, and having the *note next(): 7dc. method
increment ‘self.count’ and return it.  However, for a moderately
complicated generator, writing a corresponding class would be much
messier.  ‘Lib/test/test_generators.py’ contains a number of more
interesting examples.  The simplest one implements an in-order traversal
of a tree using generators recursively.

     # A recursive generator that generates Tree leaves in in-order.
     def inorder(t):
         if t:
             for x in inorder(t.left):
                 yield x
             yield t.label
             for x in inorder(t.right):
                 yield x

Two other examples in ‘Lib/test/test_generators.py’ produce solutions
for the N-Queens problem (placing $N$ queens on an $NxN$ chess board so
that no queen threatens another) and the Knight’s Tour (a route that
takes a knight to every square of an $NxN$ chessboard without visiting
any square twice).

The idea of generators comes from other programming languages,
especially Icon (‘https://www2.cs.arizona.edu/icon/’), where the idea of
generators is central.  In Icon, every expression and function call
behaves like a generator.  One example from “An Overview of the Icon
Programming Language” at
‘https://www2.cs.arizona.edu/icon/docs/ipd266.htm’ gives an idea of what
this looks like:

     sentence := "Store it in the neighboring harbor"
     if (i := find("or", sentence)) > 5 then write(i)

In Icon the ‘find()’ function returns the indexes at which the substring
“or” is found: 3, 23, 33.  In the *note if: 2f3. statement, ‘i’ is first
assigned a value of 3, but 3 is less than 5, so the comparison fails,
and Icon retries it with the second value of 23.  23 is greater than 5,
so the comparison now succeeds, and the code prints the value 23 to the
screen.

Python doesn’t go nearly as far as Icon in adopting generators as a
central concept.  Generators are considered a new part of the core
Python language, but learning or using them isn’t compulsory; if they
don’t solve any problems that you have, feel free to ignore them.  One
novel feature of Python’s interface as compared to Icon’s is that a
generator’s state is represented as a concrete object (the iterator)
that can be passed around to other functions or stored in a data
structure.

See also
........

PEP 255(2) - Simple Generators

     Written by Neil Schemenauer, Tim Peters, Magnus Lie Hetland.
     Implemented mostly by Neil Schemenauer and Tim Peters, with other
     fixes from the Python Labs crew.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0255/

   (2) https://peps.python.org/pep-0255/


File: python.info,  Node: PEP 237 Unifying Long Integers and Integers<2>,  Next: PEP 238 Changing the Division Operator,  Prev: PEP 255 Simple Generators<2>,  Up: What’s New in Python 2 2

1.20.5 PEP 237: Unifying Long Integers and Integers
---------------------------------------------------

In recent versions, the distinction between regular integers, which are
32-bit values on most machines, and long integers, which can be of
arbitrary size, was becoming an annoyance.  For example, on platforms
that support files larger than ‘2**32’ bytes, the ‘tell()’ method of
file objects has to return a long integer.  However, there were various
bits of Python that expected plain integers and would raise an error if
a long integer was provided instead.  For example, in Python 1.5, only
regular integers could be used as a slice index, and ‘'abc'[1L:]’ would
raise a *note TypeError: 2c3. exception with the message ‘slice index
must be int’.

Python 2.2 will shift values from short to long integers as required.
The ‘L’ suffix is no longer needed to indicate a long integer literal,
as now the compiler will choose the appropriate type.  (Using the ‘L’
suffix will be discouraged in future 2.x versions of Python, triggering
a warning in Python 2.4, and probably dropped in Python 3.0.)  Many
operations that used to raise an *note OverflowError: 888. will now
return a long integer as their result.  For example:

     >>> 1234567890123
     1234567890123L
     >>> 2 ** 64
     18446744073709551616L

In most cases, integers and long integers will now be treated
identically.  You can still distinguish them with the *note type(): d71.
built-in function, but that’s rarely needed.

See also
........

PEP 237(1) - Unifying Long Integers and Integers

     Written by Moshe Zadka and Guido van Rossum.  Implemented mostly by
     Guido van Rossum.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0237/


File: python.info,  Node: PEP 238 Changing the Division Operator,  Next: Unicode Changes,  Prev: PEP 237 Unifying Long Integers and Integers<2>,  Up: What’s New in Python 2 2

1.20.6 PEP 238: Changing the Division Operator
----------------------------------------------

The most controversial change in Python 2.2 heralds the start of an
effort to fix an old design flaw that’s been in Python from the
beginning.  Currently Python’s division operator, ‘/’, behaves like C’s
division operator when presented with two integer arguments: it returns
an integer result that’s truncated down when there would be a fractional
part.  For example, ‘3/2’ is 1, not 1.5, and ‘(-1)/2’ is -1, not -0.5.
This means that the results of division can vary unexpectedly depending
on the type of the two operands and because Python is dynamically typed,
it can be difficult to determine the possible types of the operands.

(The controversy is over whether this is 'really' a design flaw, and
whether it’s worth breaking existing code to fix this.  It’s caused
endless discussions on python-dev, and in July 2001 erupted into a storm
of acidly sarcastic postings on ‘comp.lang.python’.  I won’t argue for
either side here and will stick to describing what’s implemented in 2.2.
Read PEP 238(1) for a summary of arguments and counter-arguments.)

Because this change might break code, it’s being introduced very
gradually.  Python 2.2 begins the transition, but the switch won’t be
complete until Python 3.0.

First, I’ll borrow some terminology from PEP 238(2).  “True division” is
the division that most non-programmers are familiar with: 3/2 is 1.5,
1/4 is 0.25, and so forth.  “Floor division” is what Python’s ‘/’
operator currently does when given integer operands; the result is the
floor of the value returned by true division.  “Classic division” is the
current mixed behaviour of ‘/’; it returns the result of floor division
when the operands are integers, and returns the result of true division
when one of the operands is a floating-point number.

Here are the changes 2.2 introduces:

   * A new operator, ‘//’, is the floor division operator.  (Yes, we
     know it looks like C++’s comment symbol.)  ‘//’ 'always' performs
     floor division no matter what the types of its operands are, so ‘1
     // 2’ is 0 and ‘1.0 // 2.0’ is also 0.0.

     ‘//’ is always available in Python 2.2; you don’t need to enable it
     using a ‘__future__’ statement.

   * By including a ‘from __future__ import division’ in a module, the
     ‘/’ operator will be changed to return the result of true division,
     so ‘1/2’ is 0.5.  Without the ‘__future__’ statement, ‘/’ still
     means classic division.  The default meaning of ‘/’ will not change
     until Python 3.0.

   * Classes can define methods called *note __truediv__(): ec4. and
     *note __floordiv__(): 1543. to overload the two division operators.
     At the C level, there are also slots in the *note PyNumberMethods:
     146c. structure so extension types can define the two operators.

   * Python 2.2 supports some command-line arguments for testing whether
     code will work with the changed division semantics.  Running python
     with ‘-Q warn’ will cause a warning to be issued whenever division
     is applied to two integers.  You can use this to find code that’s
     affected by the change and fix it.  By default, Python 2.2 will
     simply perform classic division without a warning; the warning will
     be turned on by default in Python 2.3.

See also
........

PEP 238(3) - Changing the Division Operator

     Written by Moshe Zadka and Guido van Rossum.  Implemented by Guido
     van Rossum..

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0238/

   (2) https://peps.python.org/pep-0238/

   (3) https://peps.python.org/pep-0238/


File: python.info,  Node: Unicode Changes,  Next: PEP 227 Nested Scopes,  Prev: PEP 238 Changing the Division Operator,  Up: What’s New in Python 2 2

1.20.7 Unicode Changes
----------------------

Python’s Unicode support has been enhanced a bit in 2.2.  Unicode
strings are usually stored as UCS-2, as 16-bit unsigned integers.
Python 2.2 can also be compiled to use UCS-4, 32-bit unsigned integers,
as its internal encoding by supplying ‘--enable-unicode=ucs4’ to the
configure script.  (It’s also possible to specify ‘--disable-unicode’ to
completely disable Unicode support.)

When built to use UCS-4 (a “wide Python”), the interpreter can natively
handle Unicode characters from U+000000 to U+110000, so the range of
legal values for the ‘unichr()’ function is expanded accordingly.  Using
an interpreter compiled to use UCS-2 (a “narrow Python”), values greater
than 65535 will still cause ‘unichr()’ to raise a *note ValueError: 202.
exception.  This is all described in PEP 261(1), “Support for ‘wide’
Unicode characters”; consult it for further details.

Another change is simpler to explain.  Since their introduction, Unicode
strings have supported an ‘encode()’ method to convert the string to a
selected encoding such as UTF-8 or Latin-1.  A symmetric
‘decode([*encoding*])’ method has been added to 8-bit strings (though
not to Unicode strings) in 2.2.  ‘decode()’ assumes that the string is
in the specified encoding and decodes it, returning whatever is returned
by the codec.

Using this new feature, codecs have been added for tasks not directly
related to Unicode.  For example, codecs have been added for
uu-encoding, MIME’s base64 encoding, and compression with the *note
zlib: 133. module:

     >>> s = """Here is a lengthy piece of redundant, overly verbose,
     ... and repetitive text.
     ... """
     >>> data = s.encode('zlib')
     >>> data
     'x\x9c\r\xc9\xc1\r\x80 \x10\x04\xc0?Ul...'
     >>> data.decode('zlib')
     'Here is a lengthy piece of redundant, overly verbose,\nand repetitive text.\n'
     >>> print s.encode('uu')
     begin 666 <data>
     M2&5R92!I<R!A(&QE;F=T:'D@<&EE8V4@;V8@<F5D=6YD86YT+"!O=F5R;'D@
     >=F5R8F]S92P*86YD(')E<&5T:71I=F4@=&5X="X*

     end
     >>> "sheesh".encode('rot-13')
     'furrfu'

To convert a class instance to Unicode, a ‘__unicode__()’ method can be
defined by a class, analogous to ‘__str__()’.

‘encode()’, ‘decode()’, and ‘__unicode__()’ were implemented by
Marc-André Lemburg.  The changes to support using UCS-4 internally were
implemented by Fredrik Lundh and Martin von Löwis.

See also
........

PEP 261(2) - Support for ‘wide’ Unicode characters

     Written by Paul Prescod.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0261/

   (2) https://peps.python.org/pep-0261/


File: python.info,  Node: PEP 227 Nested Scopes,  Next: New and Improved Modules<3>,  Prev: Unicode Changes,  Up: What’s New in Python 2 2

1.20.8 PEP 227: Nested Scopes
-----------------------------

In Python 2.1, statically nested scopes were added as an optional
feature, to be enabled by a ‘from __future__ import nested_scopes’
directive.  In 2.2 nested scopes no longer need to be specially enabled,
and are now always present.  The rest of this section is a copy of the
description of nested scopes from my “What’s New in Python 2.1”
document; if you read it when 2.1 came out, you can skip the rest of
this section.

The largest change introduced in Python 2.1, and made complete in 2.2,
is to Python’s scoping rules.  In Python 2.0, at any given time there
are at most three namespaces used to look up variable names: local,
module-level, and the built-in namespace.  This often surprised people
because it didn’t match their intuitive expectations.  For example, a
nested recursive function definition doesn’t work:

     def f():
         ...
         def g(value):
             ...
             return g(value-1) + 1
         ...

The function ‘g()’ will always raise a *note NameError: 442. exception,
because the binding of the name ‘g’ isn’t in either its local namespace
or in the module-level namespace.  This isn’t much of a problem in
practice (how often do you recursively define interior functions like
this?), but this also made using the *note lambda: 12e4. expression
clumsier, and this was a problem in practice.  In code which uses
‘lambda’ you can often find local variables being copied by passing them
as the default values of arguments.

     def find(self, name):
         "Return list of any entries equal to 'name'"
         L = filter(lambda x, name=name: x == name,
                    self.list_attribute)
         return L

The readability of Python code written in a strongly functional style
suffers greatly as a result.

The most significant change to Python 2.2 is that static scoping has
been added to the language to fix this problem.  As a first effect, the
‘name=name’ default argument is now unnecessary in the above example.
Put simply, when a given variable name is not assigned a value within a
function (by an assignment, or the *note def: 14a9, *note class: 131f,
or *note import: 5e5. statements), references to the variable will be
looked up in the local namespace of the enclosing scope.  A more
detailed explanation of the rules, and a dissection of the
implementation, can be found in the PEP.

This change may cause some compatibility problems for code where the
same variable name is used both at the module level and as a local
variable within a function that contains further function definitions.
This seems rather unlikely though, since such code would have been
pretty confusing to read in the first place.

One side effect of the change is that the ‘from module import *’ and
‘exec’ statements have been made illegal inside a function scope under
certain conditions.  The Python reference manual has said all along that
‘from module import *’ is only legal at the top level of a module, but
the CPython interpreter has never enforced this before.  As part of the
implementation of nested scopes, the compiler which turns Python source
into bytecodes has to generate different code to access variables in a
containing scope.  ‘from module import *’ and ‘exec’ make it impossible
for the compiler to figure this out, because they add names to the local
namespace that are unknowable at compile time.  Therefore, if a function
contains function definitions or *note lambda: 12e4. expressions with
free variables, the compiler will flag this by raising a *note
SyntaxError: 18d. exception.

To make the preceding explanation a bit clearer, here’s an example:

     x = 1
     def f():
         # The next line is a syntax error
         exec 'x=2'
         def g():
             return x

Line 4 containing the ‘exec’ statement is a syntax error, since ‘exec’
would define a new local variable named ‘x’ whose value should be
accessed by ‘g()’.

This shouldn’t be much of a limitation, since ‘exec’ is rarely used in
most Python code (and when it is used, it’s often a sign of a poor
design anyway).

See also
........

PEP 227(1) - Statically Nested Scopes

     Written and implemented by Jeremy Hylton.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0227/


File: python.info,  Node: New and Improved Modules<3>,  Next: Interpreter Changes and Fixes,  Prev: PEP 227 Nested Scopes,  Up: What’s New in Python 2 2

1.20.9 New and Improved Modules
-------------------------------

   * The *note xmlrpclib: 12e. module was contributed to the standard
     library by Fredrik Lundh, providing support for writing XML-RPC
     clients.  XML-RPC is a simple remote procedure call protocol built
     on top of HTTP and XML. For example, the following snippet
     retrieves a list of RSS channels from the O’Reilly Network, and
     then lists the recent headlines for one channel:

          import xmlrpclib
          s = xmlrpclib.Server(
                'http://www.oreillynet.com/meerkat/xml-rpc/server.php')
          channels = s.meerkat.getChannels()
          # channels is a list of dictionaries, like this:
          # [{'id': 4, 'title': 'Freshmeat Daily News'}
          #  {'id': 190, 'title': '32Bits Online'},
          #  {'id': 4549, 'title': '3DGamers'}, ... ]

          # Get the items for one channel
          items = s.meerkat.getItems( {'channel': 4} )

          # 'items' is another list of dictionaries, like this:
          # [{'link': 'http://freshmeat.net/releases/52719/',
          #   'description': 'A utility which converts HTML to XSL FO.',
          #   'title': 'html2fo 0.3 (Default)'}, ... ]

     The *note SimpleXMLRPCServer: 12f. module makes it easy to create
     straightforward XML-RPC servers.  See
     ‘http://xmlrpc.scripting.com/’ for more information about XML-RPC.

   * The new *note hmac: 6a. module implements the HMAC algorithm
     described by RFC 2104(1).  (Contributed by Gerhard Häring.)

   * Several functions that originally returned lengthy tuples now
     return pseudo-sequences that still behave like tuples but also have
     mnemonic attributes such as ‘memberst_mtime’ or *note tm_year:
     1547.  The enhanced functions include *note stat(): 4a3, *note
     fstat(): dba, *note statvfs(): 1140, and *note fstatvfs(): dbb. in
     the *note os: a1. module, and *note localtime(): 1548, *note
     gmtime(): 1205, and *note strptime(): 147b. in the *note time: ee.
     module.

     For example, to obtain a file’s size using the old tuples, you’d
     end up writing something like ‘file_size =
     os.stat(filename)[stat.ST_SIZE]’, but now this can be written more
     clearly as ‘file_size = os.stat(filename).st_size’.

     The original patch for this feature was contributed by Nick
     Mathewson.

   * The Python profiler has been extensively reworked and various
     errors in its output have been corrected.  (Contributed by Fred L.
     Drake, Jr.  and Tim Peters.)

   * The *note socket: cc. module can be compiled to support IPv6;
     specify the ‘--enable-ipv6’ option to Python’s configure script.
     (Contributed by Jun-ichiro “itojun” Hagino.)

   * Two new format characters were added to the *note struct: d5.
     module for 64-bit integers on platforms that support the C long
     long type.  ‘q’ is for a signed 64-bit integer, and ‘Q’ is for an
     unsigned one.  The value is returned in Python’s long integer type.
     (Contributed by Tim Peters.)

   * In the interpreter’s interactive mode, there’s a new built-in
     function *note help(): 8e0. that uses the *note pydoc: b5. module
     introduced in Python 2.1 to provide interactive help.
     ‘help(object)’ displays any available help text about 'object'.
     ‘help()’ with no argument puts you in an online help utility, where
     you can enter the names of functions, classes, or modules to read
     their help text.  (Contributed by Guido van Rossum, using Ka-Ping
     Yee’s ‘pydoc’ module.)

   * Various bugfixes and performance improvements have been made to the
     SRE engine underlying the *note re: b9. module.  For example, the
     *note re.sub(): 2a3. and *note re.split(): 2a2. functions have been
     rewritten in C. Another contributed patch speeds up certain Unicode
     character ranges by a factor of two, and a new *note finditer():
     1549. method that returns an iterator over all the non-overlapping
     matches in a given string.  (SRE is maintained by Fredrik Lundh.
     The BIGCHARSET patch was contributed by Martin von Löwis.)

   * The *note smtplib: ca. module now supports RFC 2487(2), “Secure
     SMTP over TLS”, so it’s now possible to encrypt the SMTP traffic
     between a Python program and the mail transport agent being handed
     a message.  ‘smtplib’ also supports SMTP authentication.
     (Contributed by Gerhard Häring.)

   * The *note imaplib: 74. module, maintained by Piers Lauder, has
     support for several new extensions: the NAMESPACE extension defined
     in RFC 2342(3), SORT, GETACL and SETACL. (Contributed by Anthony
     Baxter and Michel Pelletier.)

   * The ‘rfc822’ module’s parsing of email addresses is now compliant
     with RFC 2822(4), an update to RFC 822(5).  (The module’s name is
     'not' going to be changed to ‘rfc2822’.)  A new package, *note
     email: 3b, has also been added for parsing and generating e-mail
     messages.  (Contributed by Barry Warsaw, and arising out of his
     work on Mailman.)

   * The *note difflib: 37. module now contains a new ‘Differ’ class for
     producing human-readable lists of changes (a “delta”) between two
     sequences of lines of text.  There are also two generator
     functions, ‘ndiff()’ and ‘restore()’, which respectively return a
     delta from two sequences, or one of the original sequences from a
     delta.  (Grunt work contributed by David Goodger, from ndiff.py
     code by Tim Peters who then did the generatorization.)

   * New constants ‘ascii_letters’, ‘ascii_lowercase’, and
     ‘ascii_uppercase’ were added to the *note string: d3. module.
     There were several modules in the standard library that used
     ‘string.letters’ to mean the ranges A-Za-z, but that assumption is
     incorrect when locales are in use, because ‘string.letters’ varies
     depending on the set of legal characters defined by the current
     locale.  The buggy modules have all been fixed to use
     ‘ascii_letters’ instead.  (Reported by an unknown person; fixed by
     Fred L. Drake, Jr.)

   * The *note mimetypes: 8f. module now makes it easier to use
     alternative MIME-type databases by the addition of a *note
     MimeTypes: 154a. class, which takes a list of filenames to be
     parsed.  (Contributed by Fred L. Drake, Jr.)

   * A *note Timer: 119d. class was added to the *note threading: ed.
     module that allows scheduling an activity to happen at some future
     time.  (Contributed by Itamar Shtull-Trauring.)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2104.html

   (2) https://datatracker.ietf.org/doc/html/rfc2487.html

   (3) https://datatracker.ietf.org/doc/html/rfc2342.html

   (4) https://datatracker.ietf.org/doc/html/rfc2822.html

   (5) https://datatracker.ietf.org/doc/html/rfc822.html


File: python.info,  Node: Interpreter Changes and Fixes,  Next: Other Changes and Fixes<3>,  Prev: New and Improved Modules<3>,  Up: What’s New in Python 2 2

1.20.10 Interpreter Changes and Fixes
-------------------------------------

Some of the changes only affect people who deal with the Python
interpreter at the C level because they’re writing Python extension
modules, embedding the interpreter, or just hacking on the interpreter
itself.  If you only write Python code, none of the changes described
here will affect you very much.

   * Profiling and tracing functions can now be implemented in C, which
     can operate at much higher speeds than Python-based functions and
     should reduce the overhead of profiling and tracing.  This will be
     of interest to authors of development environments for Python.  Two
     new C functions were added to Python’s API, *note
     PyEval_SetProfile(): 154c. and *note PyEval_SetTrace(): 424.  The
     existing *note sys.setprofile(): 154d. and *note sys.settrace():
     154e. functions still exist, and have simply been changed to use
     the new C-level interface.  (Contributed by Fred L. Drake, Jr.)

   * Another low-level API, primarily of interest to implementers of
     Python debuggers and development tools, was added.  *note
     PyInterpreterState_Head(): 154f. and *note
     PyInterpreterState_Next(): 1550. let a caller walk through all the
     existing interpreter objects; *note
     PyInterpreterState_ThreadHead(): 1551. and *note
     PyThreadState_Next(): 1552. allow looping over all the thread
     states for a given interpreter.  (Contributed by David Beazley.)

   * The C-level interface to the garbage collector has been changed to
     make it easier to write extension types that support garbage
     collection and to debug misuses of the functions.  Various
     functions have slightly different semantics, so a bunch of
     functions had to be renamed.  Extensions that use the old API will
     still compile but will 'not' participate in garbage collection, so
     updating them for 2.2 should be considered fairly high priority.

     To upgrade an extension module to the new API, perform the
     following steps:

   * Rename ‘Py_TPFLAGS_GC’ to *note Py_TPFLAGS_HAVE_GC: 780.

   * 
     Use *note PyObject_GC_New(): ab7. or *note PyObject_GC_NewVar(): ab8. to allocate

          objects, and *note PyObject_GC_Del(): 1553. to deallocate
          them.

   * Rename ‘PyObject_GC_Init()’ to *note PyObject_GC_Track(): 1554. and
     ‘PyObject_GC_Fini()’ to *note PyObject_GC_UnTrack(): 1555.

   * Remove ‘PyGC_HEAD_SIZE’ from object size calculations.

   * Remove calls to ‘PyObject_AS_GC()’ and ‘PyObject_FROM_GC()’.

   * A new ‘et’ format sequence was added to *note PyArg_ParseTuple():
     574.; ‘et’ takes both a parameter and an encoding name, and
     converts the parameter to the given encoding if the parameter turns
     out to be a Unicode string, or leaves it alone if it’s an 8-bit
     string, assuming it to already be in the desired encoding.  This
     differs from the ‘es’ format character, which assumes that 8-bit
     strings are in Python’s default ASCII encoding and converts them to
     the specified new encoding.  (Contributed by M.-A. Lemburg, and
     used for the MBCS support on Windows described in the following
     section.)

   * A different argument parsing function, *note PyArg_UnpackTuple():
     1556, has been added that’s simpler and presumably faster.  Instead
     of specifying a format string, the caller simply gives the minimum
     and maximum number of arguments expected, and a set of pointers to
     *note PyObject: 33a.* variables that will be filled in with
     argument values.

   * Two new flags *note METH_NOARGS: 1523. and *note METH_O: 1557. are
     available in method definition tables to simplify implementation of
     methods with no arguments or a single untyped argument.  Calling
     such methods is more efficient than calling a corresponding method
     that uses *note METH_VARARGS: 1558.  Also, the old ‘METH_OLDARGS’
     style of writing C methods is now officially deprecated.

   * Two new wrapper functions, *note PyOS_snprintf(): 1559. and *note
     PyOS_vsnprintf(): 155a. were added to provide cross-platform
     implementations for the relatively new ‘snprintf()’ and
     ‘vsnprintf()’ C lib APIs.  In contrast to the standard ‘sprintf()’
     and ‘vsprintf()’ functions, the Python versions check the bounds of
     the buffer used to protect against buffer overruns.  (Contributed
     by M.-A. Lemburg.)

   * The *note _PyTuple_Resize(): 155b. function has lost an unused
     parameter, so now it takes 2 parameters instead of 3.  The third
     argument was never used, and can simply be discarded when porting
     code from earlier versions to Python 2.2.


File: python.info,  Node: Other Changes and Fixes<3>,  Next: Acknowledgements<6>,  Prev: Interpreter Changes and Fixes,  Up: What’s New in Python 2 2

1.20.11 Other Changes and Fixes
-------------------------------

As usual there were a bunch of other improvements and bugfixes scattered
throughout the source tree.  A search through the CVS change logs finds
there were 527 patches applied and 683 bugs fixed between Python 2.1 and
2.2; 2.2.1 applied 139 patches and fixed 143 bugs; 2.2.2 applied 106
patches and fixed 82 bugs.  These figures are likely to be
underestimates.

Some of the more notable changes are:

   * The code for the MacOS port for Python, maintained by Jack Jansen,
     is now kept in the main Python CVS tree, and many changes have been
     made to support MacOS X.

     The most significant change is the ability to build Python as a
     framework, enabled by supplying the ‘--enable-framework’ option to
     the configure script when compiling Python.  According to Jack
     Jansen, “This installs a self-contained Python installation plus
     the OS X framework “glue” into
     ‘/Library/Frameworks/Python.framework’ (or another location of
     choice).  For now there is little immediate added benefit to this
     (actually, there is the disadvantage that you have to change your
     PATH to be able to find Python), but it is the basis for creating a
     full-blown Python application, porting the MacPython IDE, possibly
     using Python as a standard OSA scripting language and much more.”

     Most of the MacPython toolbox modules, which interface to MacOS
     APIs such as windowing, QuickTime, scripting, etc.  have been
     ported to OS X, but they’ve been left commented out in ‘setup.py’.
     People who want to experiment with these modules can uncomment them
     manually.

   * Keyword arguments passed to built-in functions that don’t take them
     now cause a *note TypeError: 2c3. exception to be raised, with the
     message “'function' takes no keyword arguments”.

   * Weak references, added in Python 2.1 as an extension module, are
     now part of the core because they’re used in the implementation of
     new-style classes.  The *note ReferenceError: 155d. exception has
     therefore moved from the *note weakref: 114. module to become a
     built-in exception.

   * A new script, ‘Tools/scripts/cleanfuture.py’ by Tim Peters,
     automatically removes obsolete ‘__future__’ statements from Python
     source code.

   * An additional 'flags' argument has been added to the built-in
     function *note compile(): 192, so the behaviour of ‘__future__’
     statements can now be correctly observed in simulated shells, such
     as those presented by IDLE and other development environments.
     This is described in PEP 264(1).  (Contributed by Michael Hudson.)

   * The new license introduced with Python 1.6 wasn’t GPL-compatible.
     This is fixed by some minor textual changes to the 2.2 license, so
     it’s now legal to embed Python inside a GPLed program again.  Note
     that Python itself is not GPLed, but instead is under a license
     that’s essentially equivalent to the BSD license, same as it always
     was.  The license changes were also applied to the Python 2.0.1 and
     2.1.1 releases.

   * When presented with a Unicode filename on Windows, Python will now
     convert it to an MBCS encoded string, as used by the Microsoft file
     APIs.  As MBCS is explicitly used by the file APIs, Python’s choice
     of ASCII as the default encoding turns out to be an annoyance.  On
     Unix, the locale’s character set is used if
     ‘locale.nl_langinfo(CODESET)’ is available.  (Windows support was
     contributed by Mark Hammond with assistance from Marc-André
     Lemburg.  Unix support was added by Martin von Löwis.)

   * Large file support is now enabled on Windows.  (Contributed by Tim
     Peters.)

   * The ‘Tools/scripts/ftpmirror.py’ script now parses a ‘.netrc’ file,
     if you have one.  (Contributed by Mike Romberg.)

   * Some features of the object returned by the ‘xrange()’ function are
     now deprecated, and trigger warnings when they’re accessed; they’ll
     disappear in Python 2.3.  ‘xrange’ objects tried to pretend they
     were full sequence types by supporting slicing, sequence
     multiplication, and the *note in: 2f4. operator, but these features
     were rarely used and therefore buggy.  The ‘tolist()’ method and
     the ‘start’, ‘stop’, and ‘step’ attributes are also being
     deprecated.  At the C level, the fourth argument to the
     ‘PyRange_New()’ function, ‘repeat’, has also been deprecated.

   * There were a bunch of patches to the dictionary implementation,
     mostly to fix potential core dumps if a dictionary contains objects
     that sneakily changed their hash value, or mutated the dictionary
     they were contained in.  For a while python-dev fell into a gentle
     rhythm of Michael Hudson finding a case that dumped core, Tim
     Peters fixing the bug, Michael finding another case, and round and
     round it went.

   * On Windows, Python can now be compiled with Borland C thanks to a
     number of patches contributed by Stephen Hansen, though the result
     isn’t fully functional yet.  (But this 'is' progress…)

   * Another Windows enhancement: Wise Solutions generously offered
     PythonLabs use of their InstallerMaster 8.1 system.  Earlier
     PythonLabs Windows installers used Wise 5.0a, which was beginning
     to show its age.  (Packaged up by Tim Peters.)

   * Files ending in ‘.pyw’ can now be imported on Windows.  ‘.pyw’ is a
     Windows-only thing, used to indicate that a script needs to be run
     using PYTHONW.EXE instead of PYTHON.EXE in order to prevent a DOS
     console from popping up to display the output.  This patch makes it
     possible to import such scripts, in case they’re also usable as
     modules.  (Implemented by David Bolen.)

   * On platforms where Python uses the C ‘dlopen()’ function to load
     extension modules, it’s now possible to set the flags used by
     ‘dlopen()’ using the *note sys.getdlopenflags(): 155e. and *note
     sys.setdlopenflags(): 1163. functions.  (Contributed by Bram
     Stolk.)

   * The *note pow(): 9dd. built-in function no longer supports 3
     arguments when floating-point numbers are supplied.  ‘pow(x, y, z)’
     returns ‘(x**y) % z’, but this is never useful for floating-point
     numbers, and the final result varies unpredictably depending on the
     platform.  A call such as ‘pow(2.0, 8.0, 7.0)’ will now raise a
     *note TypeError: 2c3. exception.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0264/


File: python.info,  Node: Acknowledgements<6>,  Prev: Other Changes and Fixes<3>,  Up: What’s New in Python 2 2

1.20.12 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Fred Bremmer, Keith Briggs, Andrew Dalke, Fred L. Drake, Jr.,
Carel Fellinger, David Goodger, Mark Hammond, Stephen Hansen, Michael
Hudson, Jack Jansen, Marc-André Lemburg, Martin von Löwis, Fredrik
Lundh, Michael McLay, Nick Mathewson, Paul Moore, Gustavo Niemeyer, Don
O’Donnell, Joonas Paalasma, Tim Peters, Jens Quade, Tom Reinhardt, Neil
Schemenauer, Guido van Rossum, Greg Ward, Edward Welbourne.


File: python.info,  Node: What’s New in Python 2 1,  Next: What’s New in Python 2 0,  Prev: What’s New in Python 2 2,  Up: What’s New in Python

1.21 What’s New in Python 2.1
=============================


Author: A.M. Kuchling

* Menu:

* Introduction: Introduction<2>.
* PEP 227; Nested Scopes: PEP 227 Nested Scopes<2>.
* PEP 236; __future__ Directives: PEP 236 __future__ Directives.
* PEP 207; Rich Comparisons: PEP 207 Rich Comparisons.
* PEP 230; Warning Framework: PEP 230 Warning Framework.
* PEP 229; New Build System: PEP 229 New Build System.
* PEP 205; Weak References: PEP 205 Weak References.
* PEP 232; Function Attributes: PEP 232 Function Attributes.
* PEP 235; Importing Modules on Case-Insensitive Platforms: PEP 235 Importing Modules on Case-Insensitive Platforms.
* PEP 217; Interactive Display Hook: PEP 217 Interactive Display Hook.
* PEP 208; New Coercion Model: PEP 208 New Coercion Model.
* PEP 241; Metadata in Python Packages: PEP 241 Metadata in Python Packages.
* New and Improved Modules: New and Improved Modules<4>.
* Other Changes and Fixes: Other Changes and Fixes<4>.
* Acknowledgements: Acknowledgements<7>.


File: python.info,  Node: Introduction<2>,  Next: PEP 227 Nested Scopes<2>,  Up: What’s New in Python 2 1

1.21.1 Introduction
-------------------

This article explains the new features in Python 2.1.  While there
aren’t as many changes in 2.1 as there were in Python 2.0, there are
still some pleasant surprises in store.  2.1 is the first release to be
steered through the use of Python Enhancement Proposals, or PEPs, so
most of the sizable changes have accompanying PEPs that provide more
complete documentation and a design rationale for the change.  This
article doesn’t attempt to document the new features completely, but
simply provides an overview of the new features for Python programmers.
Refer to the Python 2.1 documentation, or to the specific PEP, for more
details about any new feature that particularly interests you.

One recent goal of the Python development team has been to accelerate
the pace of new releases, with a new release coming every 6 to 9 months.
2.1 is the first release to come out at this faster pace, with the first
alpha appearing in January, 3 months after the final version of 2.0 was
released.

The final release of Python 2.1 was made on April 17, 2001.


File: python.info,  Node: PEP 227 Nested Scopes<2>,  Next: PEP 236 __future__ Directives,  Prev: Introduction<2>,  Up: What’s New in Python 2 1

1.21.2 PEP 227: Nested Scopes
-----------------------------

The largest change in Python 2.1 is to Python’s scoping rules.  In
Python 2.0, at any given time there are at most three namespaces used to
look up variable names: local, module-level, and the built-in namespace.
This often surprised people because it didn’t match their intuitive
expectations.  For example, a nested recursive function definition
doesn’t work:

     def f():
         ...
         def g(value):
             ...
             return g(value-1) + 1
         ...

The function ‘g()’ will always raise a *note NameError: 442. exception,
because the binding of the name ‘g’ isn’t in either its local namespace
or in the module-level namespace.  This isn’t much of a problem in
practice (how often do you recursively define interior functions like
this?), but this also made using the *note lambda: 12e4. expression
clumsier, and this was a problem in practice.  In code which uses
‘lambda’ you can often find local variables being copied by passing them
as the default values of arguments.

     def find(self, name):
         "Return list of any entries equal to 'name'"
         L = filter(lambda x, name=name: x == name,
                    self.list_attribute)
         return L

The readability of Python code written in a strongly functional style
suffers greatly as a result.

The most significant change to Python 2.1 is that static scoping has
been added to the language to fix this problem.  As a first effect, the
‘name=name’ default argument is now unnecessary in the above example.
Put simply, when a given variable name is not assigned a value within a
function (by an assignment, or the *note def: 14a9, *note class: 131f,
or *note import: 5e5. statements), references to the variable will be
looked up in the local namespace of the enclosing scope.  A more
detailed explanation of the rules, and a dissection of the
implementation, can be found in the PEP.

This change may cause some compatibility problems for code where the
same variable name is used both at the module level and as a local
variable within a function that contains further function definitions.
This seems rather unlikely though, since such code would have been
pretty confusing to read in the first place.

One side effect of the change is that the ‘from module import *’ and
‘exec’ statements have been made illegal inside a function scope under
certain conditions.  The Python reference manual has said all along that
‘from module import *’ is only legal at the top level of a module, but
the CPython interpreter has never enforced this before.  As part of the
implementation of nested scopes, the compiler which turns Python source
into bytecodes has to generate different code to access variables in a
containing scope.  ‘from module import *’ and ‘exec’ make it impossible
for the compiler to figure this out, because they add names to the local
namespace that are unknowable at compile time.  Therefore, if a function
contains function definitions or *note lambda: 12e4. expressions with
free variables, the compiler will flag this by raising a *note
SyntaxError: 18d. exception.

To make the preceding explanation a bit clearer, here’s an example:

     x = 1
     def f():
         # The next line is a syntax error
         exec 'x=2'
         def g():
             return x

Line 4 containing the ‘exec’ statement is a syntax error, since ‘exec’
would define a new local variable named ‘x’ whose value should be
accessed by ‘g()’.

This shouldn’t be much of a limitation, since ‘exec’ is rarely used in
most Python code (and when it is used, it’s often a sign of a poor
design anyway).

Compatibility concerns have led to nested scopes being introduced
gradually; in Python 2.1, they aren’t enabled by default, but can be
turned on within a module by using a future statement as described in
PEP 236(1).  (See the following section for further discussion of PEP
236(2).)  In Python 2.2, nested scopes will become the default and there
will be no way to turn them off, but users will have had all of 2.1’s
lifetime to fix any breakage resulting from their introduction.

See also
........

PEP 227(3) - Statically Nested Scopes

     Written and implemented by Jeremy Hylton.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0236/

   (2) https://peps.python.org/pep-0236/

   (3) https://peps.python.org/pep-0227/


File: python.info,  Node: PEP 236 __future__ Directives,  Next: PEP 207 Rich Comparisons,  Prev: PEP 227 Nested Scopes<2>,  Up: What’s New in Python 2 1

1.21.3 PEP 236: __future__ Directives
-------------------------------------

The reaction to nested scopes was widespread concern about the dangers
of breaking code with the 2.1 release, and it was strong enough to make
the Pythoneers take a more conservative approach.  This approach
consists of introducing a convention for enabling optional functionality
in release N that will become compulsory in release N+1.

The syntax uses a ‘from...import’ statement using the reserved module
name *note __future__: 0.  Nested scopes can be enabled by the following
statement:

     from __future__ import nested_scopes

While it looks like a normal *note import: 5e5. statement, it’s not;
there are strict rules on where such a future statement can be put.
They can only be at the top of a module, and must precede any Python
code or regular ‘import’ statements.  This is because such statements
can affect how the Python bytecode compiler parses code and generates
bytecode, so they must precede any statement that will result in
bytecodes being produced.

See also
........

PEP 236(1) - Back to the *note __future__: 0.

     Written by Tim Peters, and primarily implemented by Jeremy Hylton.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0236/


File: python.info,  Node: PEP 207 Rich Comparisons,  Next: PEP 230 Warning Framework,  Prev: PEP 236 __future__ Directives,  Up: What’s New in Python 2 1

1.21.4 PEP 207: Rich Comparisons
--------------------------------

In earlier versions, Python’s support for implementing comparisons on
user-defined classes and extension types was quite simple.  Classes
could implement a ‘__cmp__()’ method that was given two instances of a
class, and could only return 0 if they were equal or +1 or -1 if they
weren’t; the method couldn’t raise an exception or return anything other
than a Boolean value.  Users of Numeric Python often found this model
too weak and restrictive, because in the number-crunching programs that
numeric Python is used for, it would be more useful to be able to
perform elementwise comparisons of two matrices, returning a matrix
containing the results of a given comparison for each element.  If the
two matrices are of different sizes, then the compare has to be able to
raise an exception to signal the error.

In Python 2.1, rich comparisons were added in order to support this
need.  Python classes can now individually overload each of the ‘<’,
‘<=’, ‘>’, ‘>=’, ‘==’, and ‘!=’ operations.  The new magic method names
are:

Operation       Method name
                
---------------------------------------------
                
‘<’             *note __lt__(): 12e7.
                
                
‘<=’            *note __le__(): 1354.
                
                
‘>’             *note __gt__(): 1355.
                
                
‘>=’            *note __ge__(): 1356.
                
                
‘==’            *note __eq__(): b13.
                
                
‘!=’            *note __ne__(): 1567.
                

(The magic methods are named after the corresponding Fortran operators
‘.LT.’.  ‘.LE.’, &c.  Numeric programmers are almost certainly quite
familiar with these names and will find them easy to remember.)

Each of these magic methods is of the form ‘method(self, other)’, where
‘self’ will be the object on the left-hand side of the operator, while
‘other’ will be the object on the right-hand side.  For example, the
expression ‘A < B’ will cause ‘A.__lt__(B)’ to be called.

Each of these magic methods can return anything at all: a Boolean, a
matrix, a list, or any other Python object.  Alternatively they can
raise an exception if the comparison is impossible, inconsistent, or
otherwise meaningless.

The built-in ‘cmp(A,B)’ function can use the rich comparison machinery,
and now accepts an optional argument specifying which comparison
operation to use; this is given as one of the strings ‘"<"’, ‘"<="’,
‘">"’, ‘">="’, ‘"=="’, or ‘"!="’.  If called without the optional third
argument, ‘cmp()’ will only return -1, 0, or +1 as in previous versions
of Python; otherwise it will call the appropriate method and can return
any Python object.

There are also corresponding changes of interest to C programmers;
there’s a new slot ‘tp_richcmp’ in type objects and an API for
performing a given rich comparison.  I won’t cover the C API here, but
will refer you to PEP 207(1), or to 2.1’s C API documentation, for the
full list of related functions.

See also
........

PEP 207(2) - Rich Comparisons

     Written by Guido van Rossum, heavily based on earlier work by David
     Ascher, and implemented by Guido van Rossum.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0207/

   (2) https://peps.python.org/pep-0207/


File: python.info,  Node: PEP 230 Warning Framework,  Next: PEP 229 New Build System,  Prev: PEP 207 Rich Comparisons,  Up: What’s New in Python 2 1

1.21.5 PEP 230: Warning Framework
---------------------------------

Over its 10 years of existence, Python has accumulated a certain number
of obsolete modules and features along the way.  It’s difficult to know
when a feature is safe to remove, since there’s no way of knowing how
much code uses it — perhaps no programs depend on the feature, or
perhaps many do.  To enable removing old features in a more structured
way, a warning framework was added.  When the Python developers want to
get rid of a feature, it will first trigger a warning in the next
version of Python.  The following Python version can then drop the
feature, and users will have had a full release cycle to remove uses of
the old feature.

Python 2.1 adds the warning framework to be used in this scheme.  It
adds a *note warnings: 112. module that provide functions to issue
warnings, and to filter out warnings that you don’t want to be
displayed.  Third-party modules can also use this framework to deprecate
old features that they no longer wish to support.

For example, in Python 2.1 the ‘regex’ module is deprecated, so
importing it causes a warning to be printed:

     >>> import regex
     __main__:1: DeprecationWarning: the regex module
              is deprecated; please use the re module
     >>>

Warnings can be issued by calling the *note warnings.warn(): 1569.
function:

     warnings.warn("feature X no longer supported")

The first parameter is the warning message; an additional optional
parameters can be used to specify a particular warning category.

Filters can be added to disable certain warnings; a regular expression
pattern can be applied to the message or to the module name in order to
suppress a warning.  For example, you may have a program that uses the
‘regex’ module and not want to spare the time to convert it to use the
*note re: b9. module right now.  The warning can be suppressed by
calling

     import warnings
     warnings.filterwarnings(action = 'ignore',
                             message='.*regex module is deprecated',
                             category=DeprecationWarning,
                             module = '__main__')

This adds a filter that will apply only to warnings of the class *note
DeprecationWarning: 1a5. triggered in the *note __main__: 1. module, and
applies a regular expression to only match the message about the ‘regex’
module being deprecated, and will cause such warnings to be ignored.
Warnings can also be printed only once, printed every time the offending
code is executed, or turned into exceptions that will cause the program
to stop (unless the exceptions are caught in the usual way, of course).

Functions were also added to Python’s C API for issuing warnings; refer
to PEP 230 or to Python’s API documentation for the details.

See also
........

PEP 5(1) - Guidelines for Language Evolution

     Written by Paul Prescod, to specify procedures to be followed when
     removing old features from Python.  The policy described in this
     PEP hasn’t been officially adopted, but the eventual policy
     probably won’t be too different from Prescod’s proposal.

PEP 230(2) - Warning Framework

     Written and implemented by Guido van Rossum.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0005/

   (2) https://peps.python.org/pep-0230/


File: python.info,  Node: PEP 229 New Build System,  Next: PEP 205 Weak References,  Prev: PEP 230 Warning Framework,  Up: What’s New in Python 2 1

1.21.6 PEP 229: New Build System
--------------------------------

When compiling Python, the user had to go in and edit the
‘Modules/Setup’ file in order to enable various additional modules; the
default set is relatively small and limited to modules that compile on
most Unix platforms.  This means that on Unix platforms with many more
features, most notably Linux, Python installations often don’t contain
all useful modules they could.

Python 2.0 added the Distutils, a set of modules for distributing and
installing extensions.  In Python 2.1, the Distutils are used to compile
much of the standard library of extension modules, autodetecting which
ones are supported on the current machine.  It’s hoped that this will
make Python installations easier and more featureful.

Instead of having to edit the ‘Modules/Setup’ file in order to enable
modules, a ‘setup.py’ script in the top directory of the Python source
distribution is run at build time, and attempts to discover which
modules can be enabled by examining the modules and header files on the
system.  If a module is configured in ‘Modules/Setup’, the ‘setup.py’
script won’t attempt to compile that module and will defer to the
‘Modules/Setup’ file’s contents.  This provides a way to specific any
strange command-line flags or libraries that are required for a specific
platform.

In another far-reaching change to the build mechanism, Neil Schemenauer
restructured things so Python now uses a single makefile that isn’t
recursive, instead of makefiles in the top directory and in each of the
‘Python/’, ‘Parser/’, ‘Objects/’, and ‘Modules/’ subdirectories.  This
makes building Python faster and also makes hacking the Makefiles
clearer and simpler.

See also
........

PEP 229(1) - Using Distutils to Build Python

     Written and implemented by A.M. Kuchling.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0229/


File: python.info,  Node: PEP 205 Weak References,  Next: PEP 232 Function Attributes,  Prev: PEP 229 New Build System,  Up: What’s New in Python 2 1

1.21.7 PEP 205: Weak References
-------------------------------

Weak references, available through the *note weakref: 114. module, are a
minor but useful new data type in the Python programmer’s toolbox.

Storing a reference to an object (say, in a dictionary or a list) has
the side effect of keeping that object alive forever.  There are a few
specific cases where this behaviour is undesirable, object caches being
the most common one, and another being circular references in data
structures such as trees.

For example, consider a memoizing function that caches the results of
another function ‘f(x)’ by storing the function’s argument and its
result in a dictionary:

     _cache = {}
     def memoize(x):
         if _cache.has_key(x):
             return _cache[x]

         retval = f(x)

         # Cache the returned object
         _cache[x] = retval

         return retval

This version works for simple things such as integers, but it has a side
effect; the ‘_cache’ dictionary holds a reference to the return values,
so they’ll never be deallocated until the Python process exits and
cleans up.  This isn’t very noticeable for integers, but if ‘f()’
returns an object, or a data structure that takes up a lot of memory,
this can be a problem.

Weak references provide a way to implement a cache that won’t keep
objects alive beyond their time.  If an object is only accessible
through weak references, the object will be deallocated and the weak
references will now indicate that the object it referred to no longer
exists.  A weak reference to an object 'obj' is created by calling ‘wr =
weakref.ref(obj)’.  The object being referred to is returned by calling
the weak reference as if it were a function: ‘wr()’.  It will return the
referenced object, or ‘None’ if the object no longer exists.

This makes it possible to write a ‘memoize()’ function whose cache
doesn’t keep objects alive, by storing weak references in the cache.

     _cache = {}
     def memoize(x):
         if _cache.has_key(x):
             obj = _cache[x]()
             # If weak reference object still exists,
             # return it
             if obj is not None: return obj

         retval = f(x)

         # Cache a weak reference
         _cache[x] = weakref.ref(retval)

         return retval

The *note weakref: 114. module also allows creating proxy objects which
behave like weak references — an object referenced only by proxy objects
is deallocated – but instead of requiring an explicit call to retrieve
the object, the proxy transparently forwards all operations to the
object as long as the object still exists.  If the object is
deallocated, attempting to use a proxy will cause a
‘weakref.ReferenceError’ exception to be raised.

     proxy = weakref.proxy(obj)
     proxy.attr   # Equivalent to obj.attr
     proxy.meth() # Equivalent to obj.meth()
     del obj
     proxy.attr   # raises weakref.ReferenceError

See also
........

PEP 205(1) - Weak References

     Written and implemented by Fred L. Drake, Jr.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0205/


File: python.info,  Node: PEP 232 Function Attributes,  Next: PEP 235 Importing Modules on Case-Insensitive Platforms,  Prev: PEP 205 Weak References,  Up: What’s New in Python 2 1

1.21.8 PEP 232: Function Attributes
-----------------------------------

In Python 2.1, functions can now have arbitrary information attached to
them.  People were often using docstrings to hold information about
functions and methods, because the *note __doc__: 121e. attribute was
the only way of attaching any information to a function.  For example,
in the Zope web application server, functions are marked as safe for
public access by having a docstring, and in John Aycock’s SPARK parsing
framework, docstrings hold parts of the BNF grammar to be parsed.  This
overloading is unfortunate, since docstrings are really intended to hold
a function’s documentation; for example, it means you can’t properly
document functions intended for private use in Zope.

Arbitrary attributes can now be set and retrieved on functions using the
regular Python syntax:

     def f(): pass

     f.publish = 1
     f.secure = 1
     f.grammar = "A ::= B (C D)*"

The dictionary containing attributes can be accessed as the function’s
*note __dict__: 131a.  Unlike the *note __dict__: c7e. attribute of
class instances, in functions you can actually assign a new dictionary
to ‘__dict__’, though the new value is restricted to a regular Python
dictionary; you 'can’t' be tricky and set it to a ‘UserDict’ instance,
or any other random object that behaves like a mapping.

See also
........

PEP 232(1) - Function Attributes

     Written and implemented by Barry Warsaw.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0232/


File: python.info,  Node: PEP 235 Importing Modules on Case-Insensitive Platforms,  Next: PEP 217 Interactive Display Hook,  Prev: PEP 232 Function Attributes,  Up: What’s New in Python 2 1

1.21.9 PEP 235: Importing Modules on Case-Insensitive Platforms
---------------------------------------------------------------

Some operating systems have filesystems that are case-insensitive, MacOS
and Windows being the primary examples; on these systems, it’s
impossible to distinguish the filenames ‘FILE.PY’ and ‘file.py’, even
though they do store the file’s name in its original case (they’re
case-preserving, too).

In Python 2.1, the *note import: 5e5. statement will work to simulate
case-sensitivity on case-insensitive platforms.  Python will now search
for the first case-sensitive match by default, raising an *note
ImportError: 41c. if no such file is found, so ‘import file’ will not
import a module named ‘FILE.PY’.  Case-insensitive matching can be
requested by setting the *note PYTHONCASEOK: 966. environment variable
before starting the Python interpreter.


File: python.info,  Node: PEP 217 Interactive Display Hook,  Next: PEP 208 New Coercion Model,  Prev: PEP 235 Importing Modules on Case-Insensitive Platforms,  Up: What’s New in Python 2 1

1.21.10 PEP 217: Interactive Display Hook
-----------------------------------------

When using the Python interpreter interactively, the output of commands
is displayed using the built-in *note repr(): 803. function.  In Python
2.1, the variable *note sys.displayhook(): 156f. can be set to a
callable object which will be called instead of ‘repr()’.  For example,
you can set it to a special pretty-printing function:

     >>> # Create a recursive data structure
     ... L = [1,2,3]
     >>> L.append(L)
     >>> L # Show Python's default output
     [1, 2, 3, [...]]
     >>> # Use pprint.pprint() as the display function
     ... import sys, pprint
     >>> sys.displayhook = pprint.pprint
     >>> L
     [1, 2, 3,  <Recursion on list with id=135143996>]
     >>>

See also
........

PEP 217(1) - Display Hook for Interactive Use

     Written and implemented by Moshe Zadka.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0217/


File: python.info,  Node: PEP 208 New Coercion Model,  Next: PEP 241 Metadata in Python Packages,  Prev: PEP 217 Interactive Display Hook,  Up: What’s New in Python 2 1

1.21.11 PEP 208: New Coercion Model
-----------------------------------

How numeric coercion is done at the C level was significantly modified.
This will only affect the authors of C extensions to Python, allowing
them more flexibility in writing extension types that support numeric
operations.

Extension types can now set the type flag ‘Py_TPFLAGS_CHECKTYPES’ in
their ‘PyTypeObject’ structure to indicate that they support the new
coercion model.  In such extension types, the numeric slot functions can
no longer assume that they’ll be passed two arguments of the same type;
instead they may be passed two arguments of differing types, and can
then perform their own internal coercion.  If the slot function is
passed a type it can’t handle, it can indicate the failure by returning
a reference to the ‘Py_NotImplemented’ singleton value.  The numeric
functions of the other type will then be tried, and perhaps they can
handle the operation; if the other type also returns
‘Py_NotImplemented’, then a *note TypeError: 2c3. will be raised.
Numeric methods written in Python can also return ‘Py_NotImplemented’,
causing the interpreter to act as if the method did not exist (perhaps
raising a ‘TypeError’, perhaps trying another object’s numeric methods).

See also
........

PEP 208(1) - Reworking the Coercion Model

     Written and implemented by Neil Schemenauer, heavily based upon
     earlier work by Marc-André Lemburg.  Read this to understand the
     fine points of how numeric operations will now be processed at the
     C level.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0208/


File: python.info,  Node: PEP 241 Metadata in Python Packages,  Next: New and Improved Modules<4>,  Prev: PEP 208 New Coercion Model,  Up: What’s New in Python 2 1

1.21.12 PEP 241: Metadata in Python Packages
--------------------------------------------

A common complaint from Python users is that there’s no single catalog
of all the Python modules in existence.  T. Middleton’s Vaults of
Parnassus at ‘www.vex.net/parnassus/’ (retired in February 2009,
available in the Internet Archive Wayback Machine(1)) was the largest
catalog of Python modules, but registering software at the Vaults is
optional, and many people did not bother.

As a first small step toward fixing the problem, Python software
packaged using the Distutils ‘sdist’ command will include a file named
‘PKG-INFO’ containing information about the package such as its name,
version, and author (metadata, in cataloguing terminology).  PEP 241(2)
contains the full list of fields that can be present in the ‘PKG-INFO’
file.  As people began to package their software using Python 2.1, more
and more packages will include metadata, making it possible to build
automated cataloguing systems and experiment with them.  With the result
experience, perhaps it’ll be possible to design a really good catalog
and then build support for it into Python 2.2.  For example, the
Distutils ‘sdist’ and ‘bdist_*’ commands could support an ‘upload’
option that would automatically upload your package to a catalog server.

You can start creating packages containing ‘PKG-INFO’ even if you’re not
using Python 2.1, since a new release of the Distutils will be made for
users of earlier Python versions.  Version 1.0.2 of the Distutils
includes the changes described in PEP 241(3), as well as various
bugfixes and enhancements.  It will be available from the Distutils SIG
at ‘https://www.python.org/community/sigs/current/distutils-sig/’.

See also
........

PEP 241(4) - Metadata for Python Software Packages

     Written and implemented by A.M. Kuchling.

PEP 243(5) - Module Repository Upload Mechanism

     Written by Sean Reifschneider, this draft PEP describes a proposed
     mechanism for uploading Python packages to a central server.

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20090130140102/http://www.vex.net/parnassus/

   (2) https://peps.python.org/pep-0241/

   (3) https://peps.python.org/pep-0241/

   (4) https://peps.python.org/pep-0241/

   (5) https://peps.python.org/pep-0243/


File: python.info,  Node: New and Improved Modules<4>,  Next: Other Changes and Fixes<4>,  Prev: PEP 241 Metadata in Python Packages,  Up: What’s New in Python 2 1

1.21.13 New and Improved Modules
--------------------------------

   * Ka-Ping Yee contributed two new modules: ‘inspect.py’, a module for
     getting information about live Python code, and ‘pydoc.py’, a
     module for interactively converting docstrings to HTML or text.  As
     a bonus, ‘Tools/scripts/pydoc’, which is now automatically
     installed, uses ‘pydoc.py’ to display documentation given a Python
     module, package, or class name.  For example, ‘pydoc xml.dom’
     displays the following:

          Python Library Documentation: package xml.dom in xml

          NAME
              xml.dom - W3C Document Object Model implementation for Python.

          FILE
              /usr/local/lib/python2.1/xml/dom/__init__.pyc

          DESCRIPTION
              The Python mapping of the Document Object Model is documented in the
              Python Library Reference in the section on the xml.dom package.

              This package contains the following modules:
                ...

     ‘pydoc’ also includes a Tk-based interactive help browser.  ‘pydoc’
     quickly becomes addictive; try it out!

   * Two different modules for unit testing were added to the standard
     library.  The *note doctest: 3a. module, contributed by Tim Peters,
     provides a testing framework based on running embedded examples in
     docstrings and comparing the results against the expected output.
     PyUnit, contributed by Steve Purcell, is a unit testing framework
     inspired by JUnit, which was in turn an adaptation of Kent Beck’s
     Smalltalk testing framework.  See ‘https://pyunit.sourceforge.net/’
     for more information about PyUnit.

   * The *note difflib: 37. module contains a class, *note
     SequenceMatcher: 1054, which compares two sequences and computes
     the changes required to transform one sequence into the other.  For
     example, this module can be used to write a tool similar to the
     Unix ‘diff’ program, and in fact the sample program
     ‘Tools/scripts/ndiff.py’ demonstrates how to write such a script.

   * *note curses.panel: 2d, a wrapper for the panel library, part of
     ncurses and of SYSV curses, was contributed by Thomas Gellekum.
     The panel library provides windows with the additional feature of
     depth.  Windows can be moved higher or lower in the depth ordering,
     and the panel library figures out where panels overlap and which
     sections are visible.

   * The PyXML package has gone through a few releases since Python 2.0,
     and Python 2.1 includes an updated version of the *note xml: 120.
     package.  Some of the noteworthy changes include support for Expat
     1.2 and later versions, the ability for Expat parsers to handle
     files in any encoding supported by Python, and various bugfixes for
     SAX, DOM, and the ‘minidom’ module.

   * Ping also contributed another hook for handling uncaught
     exceptions.  *note sys.excepthook(): 811. can be set to a callable
     object.  When an exception isn’t caught by any *note try:
     6ec.…*note except: 18b. blocks, the exception will be passed to
     ‘sys.excepthook()’, which can then do whatever it likes.  At the
     Ninth Python Conference, Ping demonstrated an application for this
     hook: printing an extended traceback that not only lists the stack
     frames, but also lists the function arguments and the local
     variables for each frame.

   * Various functions in the *note time: ee. module, such as *note
     asctime(): 122c. and *note localtime(): 1548, require a
     floating-point argument containing the time in seconds since the
     epoch.  The most common use of these functions is to work with the
     current time, so the floating-point argument has been made
     optional; when a value isn’t provided, the current time will be
     used.  For example, log file entries usually need a string
     containing the current time; in Python 2.1, ‘time.asctime()’ can be
     used, instead of the lengthier
     ‘time.asctime(time.localtime(time.time()))’ that was previously
     required.

     This change was proposed and implemented by Thomas Wouters.

   * The *note ftplib: 5e. module now defaults to retrieving files in
     passive mode, because passive mode is more likely to work from
     behind a firewall.  This request came from the Debian bug tracking
     system, since other Debian packages use ‘ftplib’ to retrieve files
     and then don’t work from behind a firewall.  It’s deemed unlikely
     that this will cause problems for anyone, because Netscape defaults
     to passive mode and few people complain, but if passive mode is
     unsuitable for your application or network setup, call
     ‘set_pasv(0)’ on FTP objects to disable passive mode.

   * Support for raw socket access has been added to the *note socket:
     cc. module, contributed by Grant Edwards.

   * The *note pstats: b0. module now contains a simple interactive
     statistics browser for displaying timing profiles for Python
     programs, invoked when the module is run as a script.  Contributed
     by Eric S. Raymond.

   * A new implementation-dependent function, ‘sys._getframe([depth])’,
     has been added to return a given frame object from the current call
     stack.  *note sys._getframe(): 6e4. returns the frame at the top of
     the call stack; if the optional integer argument 'depth' is
     supplied, the function returns the frame that is 'depth' calls
     below the top of the stack.  For example, ‘sys._getframe(1)’
     returns the caller’s frame object.

     This function is only present in CPython, not in Jython or the .NET
     implementation.  Use it for debugging, and resist the temptation to
     put it into production code.


File: python.info,  Node: Other Changes and Fixes<4>,  Next: Acknowledgements<7>,  Prev: New and Improved Modules<4>,  Up: What’s New in Python 2 1

1.21.14 Other Changes and Fixes
-------------------------------

There were relatively few smaller changes made in Python 2.1 due to the
shorter release cycle.  A search through the CVS change logs turns up
117 patches applied, and 136 bugs fixed; both figures are likely to be
underestimates.  Some of the more notable changes are:

   * A specialized object allocator is now optionally available, that
     should be faster than the system ‘malloc()’ and have less memory
     overhead.  The allocator uses C’s ‘malloc()’ function to get large
     pools of memory, and then fulfills smaller memory requests from
     these pools.  It can be enabled by providing the ‘--with-pymalloc’
     option to the ‘configure’ script; see ‘Objects/obmalloc.c’ for the
     implementation details.

     Authors of C extension modules should test their code with the
     object allocator enabled, because some incorrect code may break,
     causing core dumps at runtime.  There are a bunch of memory
     allocation functions in Python’s C API that have previously been
     just aliases for the C library’s ‘malloc()’ and ‘free()’, meaning
     that if you accidentally called mismatched functions, the error
     wouldn’t be noticeable.  When the object allocator is enabled,
     these functions aren’t aliases of ‘malloc()’ and ‘free()’ any more,
     and calling the wrong function to free memory will get you a core
     dump.  For example, if memory was allocated using *note PyMem_New:
     1574, it has to be freed using *note PyMem_Del(): 1575, not
     ‘free()’.  A few modules included with Python fell afoul of this
     and had to be fixed; doubtless there are more third-party modules
     that will have the same problem.

     The object allocator was contributed by Vladimir Marangozov.

   * The speed of line-oriented file I/O has been improved because
     people often complain about its lack of speed, and because it’s
     often been used as a naïve benchmark.  The *note readline(): ba.
     method of file objects has therefore been rewritten to be much
     faster.  The exact amount of the speedup will vary from platform to
     platform depending on how slow the C library’s ‘getc()’ was, but is
     around 66%, and potentially much faster on some particular
     operating systems.  Tim Peters did much of the benchmarking and
     coding for this change, motivated by a discussion in
     comp.lang.python.

     A new module and method for file objects was also added,
     contributed by Jeff Epler.  The new method, ‘xreadlines()’, is
     similar to the existing ‘xrange()’ built-in.  ‘xreadlines()’
     returns an opaque sequence object that only supports being iterated
     over, reading a line on every iteration but not reading the entire
     file into memory as the existing ‘readlines()’ method does.  You’d
     use it like this:

          for line in sys.stdin.xreadlines():
              # ... do something for each line ...
              ...

     For a fuller discussion of the line I/O changes, see the python-dev
     summary for January 1–15, 2001 at
     ‘https://mail.python.org/pipermail/python-dev/2001-January/’.

   * A new method, *note popitem(): 1576, was added to dictionaries to
     enable destructively iterating through the contents of a
     dictionary; this can be faster for large dictionaries because
     there’s no need to construct a list containing all the keys or
     values.  ‘D.popitem()’ removes a random ‘(key, value)’ pair from
     the dictionary ‘D’ and returns it as a 2-tuple.  This was
     implemented mostly by Tim Peters and Guido van Rossum, after a
     suggestion and preliminary patch by Moshe Zadka.

   * Modules can now control which names are imported when ‘from module
     import *’ is used, by defining an ‘__all__’ attribute containing a
     list of names that will be imported.  One common complaint is that
     if the module imports other modules such as *note sys: d9. or *note
     string: d3, ‘from module import *’ will add them to the importing
     module’s namespace.  To fix this, simply list the public names in
     ‘__all__’:

          # List public names
          __all__ = ['Database', 'open']

     A stricter version of this patch was first suggested and
     implemented by Ben Wolfson, but after some python-dev discussion, a
     weaker final version was checked in.

   * Applying *note repr(): 803. to strings previously used octal
     escapes for non-printable characters; for example, a newline was
     ‘'\012'’.  This was a vestigial trace of Python’s C ancestry, but
     today octal is of very little practical use.  Ka-Ping Yee suggested
     using hex escapes instead of octal ones, and using the ‘\n’, ‘\t’,
     ‘\r’ escapes for the appropriate characters, and implemented this
     new formatting.

   * Syntax errors detected at compile-time can now raise exceptions
     containing the filename and line number of the error, a pleasant
     side effect of the compiler reorganization done by Jeremy Hylton.

   * C extensions which import other modules have been changed to use
     *note PyImport_ImportModule(): 3c1, which means that they will use
     any import hooks that have been installed.  This is also encouraged
     for third-party extensions that need to import some other module
     from C code.

   * The size of the Unicode character database was shrunk by another
     340K thanks to Fredrik Lundh.

   * Some new ports were contributed: MacOS X (by Steven Majewski),
     Cygwin (by Jason Tishler); RISCOS (by Dietmar Schwertberger);
     Unixware 7 (by Billy G. Allie).

And there’s the usual list of minor bugfixes, minor memory leaks,
docstring edits, and other tweaks, too lengthy to be worth itemizing;
see the CVS logs for the full details if you want them.


File: python.info,  Node: Acknowledgements<7>,  Prev: Other Changes and Fixes<4>,  Up: What’s New in Python 2 1

1.21.15 Acknowledgements
------------------------

The author would like to thank the following people for offering
suggestions on various drafts of this article: Graeme Cross, David
Goodger, Jay Graves, Michael Hudson, Marc-André Lemburg, Fredrik Lundh,
Neil Schemenauer, Thomas Wouters.


File: python.info,  Node: What’s New in Python 2 0,  Next: Changelog,  Prev: What’s New in Python 2 1,  Up: What’s New in Python

1.22 What’s New in Python 2.0
=============================


Author: A.M. Kuchling and Moshe Zadka

* Menu:

* Introduction: Introduction<3>.
* What About Python 1.6?: What About Python 1 6?.
* New Development Process::
* Unicode: Unicode<2>.
* List Comprehensions::
* Augmented Assignment::
* String Methods::
* Garbage Collection of Cycles::
* Other Core Changes::
* Porting to 2.0: Porting to 2 0.
* Extending/Embedding Changes::
* Distutils; Making Modules Easy to Install: Distutils Making Modules Easy to Install.
* XML Modules::
* Module changes::
* New modules::
* IDLE Improvements::
* Deleted and Deprecated Modules::
* Acknowledgements: Acknowledgements<8>.


File: python.info,  Node: Introduction<3>,  Next: What About Python 1 6?,  Up: What’s New in Python 2 0

1.22.1 Introduction
-------------------

A new release of Python, version 2.0, was released on October 16, 2000.
This article covers the exciting new features in 2.0, highlights some
other useful changes, and points out a few incompatible changes that may
require rewriting code.

Python’s development never completely stops between releases, and a
steady flow of bug fixes and improvements are always being submitted.  A
host of minor fixes, a few optimizations, additional docstrings, and
better error messages went into 2.0; to list them all would be
impossible, but they’re certainly significant.  Consult the publicly
available CVS logs if you want to see the full list.  This progress is
due to the five developers working for PythonLabs are now getting paid
to spend their days fixing bugs, and also due to the improved
communication resulting from moving to SourceForge.


File: python.info,  Node: What About Python 1 6?,  Next: New Development Process,  Prev: Introduction<3>,  Up: What’s New in Python 2 0

1.22.2 What About Python 1.6?
-----------------------------

Python 1.6 can be thought of as the Contractual Obligations Python
release.  After the core development team left CNRI in May 2000, CNRI
requested that a 1.6 release be created, containing all the work on
Python that had been performed at CNRI. Python 1.6 therefore represents
the state of the CVS tree as of May 2000, with the most significant new
feature being Unicode support.  Development continued after May, of
course, so the 1.6 tree received a few fixes to ensure that it’s
forward-compatible with Python 2.0.  1.6 is therefore part of Python’s
evolution, and not a side branch.

So, should you take much interest in Python 1.6?  Probably not.  The
1.6final and 2.0beta1 releases were made on the same day (September 5,
2000), the plan being to finalize Python 2.0 within a month or so.  If
you have applications to maintain, there seems little point in breaking
things by moving to 1.6, fixing them, and then having another round of
breakage within a month by moving to 2.0; you’re better off just going
straight to 2.0.  Most of the really interesting features described in
this document are only in 2.0, because a lot of work was done between
May and September.


File: python.info,  Node: New Development Process,  Next: Unicode<2>,  Prev: What About Python 1 6?,  Up: What’s New in Python 2 0

1.22.3 New Development Process
------------------------------

The most important change in Python 2.0 may not be to the code at all,
but to how Python is developed: in May 2000 the Python developers began
using the tools made available by SourceForge for storing source code,
tracking bug reports, and managing the queue of patch submissions.  To
report bugs or submit patches for Python 2.0, use the bug tracking and
patch manager tools available from Python’s project page, located at
‘https://sourceforge.net/projects/python/’.

The most important of the services now hosted at SourceForge is the
Python CVS tree, the version-controlled repository containing the source
code for Python.  Previously, there were roughly 7 or so people who had
write access to the CVS tree, and all patches had to be inspected and
checked in by one of the people on this short list.  Obviously, this
wasn’t very scalable.  By moving the CVS tree to SourceForge, it became
possible to grant write access to more people; as of September 2000
there were 27 people able to check in changes, a fourfold increase.
This makes possible large-scale changes that wouldn’t be attempted if
they’d have to be filtered through the small group of core developers.
For example, one day Peter Schneider-Kamp took it into his head to drop
K&R C compatibility and convert the C source for Python to ANSI C. After
getting approval on the python-dev mailing list, he launched into a
flurry of checkins that lasted about a week, other developers joined in
to help, and the job was done.  If there were only 5 people with write
access, probably that task would have been viewed as “nice, but not
worth the time and effort needed” and it would never have gotten done.

The shift to using SourceForge’s services has resulted in a remarkable
increase in the speed of development.  Patches now get submitted,
commented on, revised by people other than the original submitter, and
bounced back and forth between people until the patch is deemed worth
checking in.  Bugs are tracked in one central location and can be
assigned to a specific person for fixing, and we can count the number of
open bugs to measure progress.  This didn’t come without a cost:
developers now have more e-mail to deal with, more mailing lists to
follow, and special tools had to be written for the new environment.
For example, SourceForge sends default patch and bug notification e-mail
messages that are completely unhelpful, so Ka-Ping Yee wrote an HTML
screen-scraper that sends more useful messages.

The ease of adding code caused a few initial growing pains, such as code
was checked in before it was ready or without getting clear agreement
from the developer group.  The approval process that has emerged is
somewhat similar to that used by the Apache group.  Developers can vote
+1, +0, -0, or -1 on a patch; +1 and -1 denote acceptance or rejection,
while +0 and -0 mean the developer is mostly indifferent to the change,
though with a slight positive or negative slant.  The most significant
change from the Apache model is that the voting is essentially advisory,
letting Guido van Rossum, who has Benevolent Dictator For Life status,
know what the general opinion is.  He can still ignore the result of a
vote, and approve or reject a change even if the community disagrees
with him.

Producing an actual patch is the last step in adding a new feature, and
is usually easy compared to the earlier task of coming up with a good
design.  Discussions of new features can often explode into lengthy
mailing list threads, making the discussion hard to follow, and no one
can read every posting to python-dev.  Therefore, a relatively formal
process has been set up to write Python Enhancement Proposals (PEPs),
modelled on the internet RFC process.  PEPs are draft documents that
describe a proposed new feature, and are continually revised until the
community reaches a consensus, either accepting or rejecting the
proposal.  Quoting from the introduction to PEP 1(1), “PEP Purpose and
Guidelines”:

     PEP stands for Python Enhancement Proposal.  A PEP is a design
     document providing information to the Python community, or
     describing a new feature for Python.  The PEP should provide a
     concise technical specification of the feature and a rationale for
     the feature.

     We intend PEPs to be the primary mechanisms for proposing new
     features, for collecting community input on an issue, and for
     documenting the design decisions that have gone into Python.  The
     PEP author is responsible for building consensus within the
     community and documenting dissenting opinions.

Read the rest of PEP 1(2) for the details of the PEP editorial process,
style, and format.  PEPs are kept in the Python CVS tree on SourceForge,
though they’re not part of the Python 2.0 distribution, and are also
available in HTML form from ‘https://peps.python.org/’.  As of September
2000, there are 25 PEPs, ranging from PEP 201(3), “Lockstep Iteration”,
to PEP 225, “Elementwise/Objectwise Operators”.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0001/

   (2) https://peps.python.org/pep-0001/

   (3) https://peps.python.org/pep-0201/


File: python.info,  Node: Unicode<2>,  Next: List Comprehensions,  Prev: New Development Process,  Up: What’s New in Python 2 0

1.22.4 Unicode
--------------

The largest new feature in Python 2.0 is a new fundamental data type:
Unicode strings.  Unicode uses 16-bit numbers to represent characters
instead of the 8-bit number used by ASCII, meaning that 65,536 distinct
characters can be supported.

The final interface for Unicode support was arrived at through countless
often-stormy discussions on the python-dev mailing list, and mostly
implemented by Marc-André Lemburg, based on a Unicode string type
implementation by Fredrik Lundh.  A detailed explanation of the
interface was written up as PEP 100(1), “Python Unicode Integration”.
This article will simply cover the most significant points about the
Unicode interfaces.

In Python source code, Unicode strings are written as ‘u"string"’.
Arbitrary Unicode characters can be written using a new escape sequence,
‘\uHHHH’, where 'HHHH' is a 4-digit hexadecimal number from 0000 to
FFFF.  The existing ‘\xHH’ escape sequence can also be used, and octal
escapes can be used for characters up to U+01FF, which is represented by
‘\777’.

Unicode strings, just like regular strings, are an immutable sequence
type.  They can be indexed and sliced, but not modified in place.
Unicode strings have an ‘encode( [encoding] )’ method that returns an
8-bit string in the desired encoding.  Encodings are named by strings,
such as ‘'ascii'’, ‘'utf-8'’, ‘'iso-8859-1'’, or whatever.  A codec API
is defined for implementing and registering new encodings that are then
available throughout a Python program.  If an encoding isn’t specified,
the default encoding is usually 7-bit ASCII, though it can be changed
for your Python installation by calling the
‘sys.setdefaultencoding(encoding)’ function in a customized version of
‘site.py’.

Combining 8-bit and Unicode strings always coerces to Unicode, using the
default ASCII encoding; the result of ‘'a' + u'bc'’ is ‘u'abc'’.

New built-in functions have been added, and existing built-ins modified
to support Unicode:

   * ‘unichr(ch)’ returns a Unicode string 1 character long, containing
     the character 'ch'.

   * ‘ord(u)’, where 'u' is a 1-character regular or Unicode string,
     returns the number of the character as an integer.

   * ‘unicode(string [, encoding] [, errors] )’ creates a Unicode string
     from an 8-bit string.  ‘encoding’ is a string naming the encoding
     to use.  The ‘errors’ parameter specifies the treatment of
     characters that are invalid for the current encoding; passing
     ‘'strict'’ as the value causes an exception to be raised on any
     encoding error, while ‘'ignore'’ causes errors to be silently
     ignored and ‘'replace'’ uses U+FFFD, the official replacement
     character, in case of any problems.

   * The ‘exec’ statement, and various built-ins such as ‘eval()’,
     ‘getattr()’, and ‘setattr()’ will also accept Unicode strings as
     well as regular strings.  (It’s possible that the process of fixing
     this missed some built-ins; if you find a built-in function that
     accepts strings but doesn’t accept Unicode strings at all, please
     report it as a bug.)

A new module, *note unicodedata: 105, provides an interface to Unicode
character properties.  For example, ‘unicodedata.category(u'A')’ returns
the 2-character string ‘Lu’, the ‘L’ denoting it’s a letter, and ‘u’
meaning that it’s uppercase.  ‘unicodedata.bidirectional(u'\u0660')’
returns ‘AN’, meaning that U+0660 is an Arabic number.

The *note codecs: 1b. module contains functions to look up existing
encodings and register new ones.  Unless you want to implement a new
encoding, you’ll most often use the ‘codecs.lookup(encoding)’ function,
which returns a 4-element tuple: ‘(encode_func, decode_func,
stream_reader, stream_writer)’.

   * 'encode_func' is a function that takes a Unicode string, and
     returns a 2-tuple ‘(string, length)’.  'string' is an 8-bit string
     containing a portion (perhaps all) of the Unicode string converted
     into the given encoding, and 'length' tells you how much of the
     Unicode string was converted.

   * 'decode_func' is the opposite of 'encode_func', taking an 8-bit
     string and returning a 2-tuple ‘(ustring, length)’, consisting of
     the resulting Unicode string 'ustring' and the integer 'length'
     telling how much of the 8-bit string was consumed.

   * 'stream_reader' is a class that supports decoding input from a
     stream.  'stream_reader(file_obj)' returns an object that supports
     the ‘read()’, ‘readline()’, and ‘readlines()’ methods.  These
     methods will all translate from the given encoding and return
     Unicode strings.

   * 'stream_writer', similarly, is a class that supports encoding
     output to a stream.  'stream_writer(file_obj)' returns an object
     that supports the ‘write()’ and ‘writelines()’ methods.  These
     methods expect Unicode strings, translating them to the given
     encoding on output.

For example, the following code writes a Unicode string into a file,
encoding it as UTF-8:

     import codecs

     unistr = u'\u0660\u2000ab ...'

     (UTF8_encode, UTF8_decode,
      UTF8_streamreader, UTF8_streamwriter) = codecs.lookup('UTF-8')

     output = UTF8_streamwriter( open( '/tmp/output', 'wb') )
     output.write( unistr )
     output.close()

The following code would then read UTF-8 input from the file:

     input = UTF8_streamreader( open( '/tmp/output', 'rb') )
     print repr(input.read())
     input.close()

Unicode-aware regular expressions are available through the *note re:
b9. module, which has a new underlying implementation called SRE written
by Fredrik Lundh of Secret Labs AB.

A ‘-U’ command line option was added which causes the Python compiler to
interpret all string literals as Unicode string literals.  This is
intended to be used in testing and future-proofing your Python code,
since some future version of Python may drop support for 8-bit strings
and provide only Unicode strings.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0100/


File: python.info,  Node: List Comprehensions,  Next: Augmented Assignment,  Prev: Unicode<2>,  Up: What’s New in Python 2 0

1.22.5 List Comprehensions
--------------------------

Lists are a workhorse data type in Python, and many programs manipulate
a list at some point.  Two common operations on lists are to loop over
them, and either pick out the elements that meet a certain criterion, or
apply some function to each element.  For example, given a list of
strings, you might want to pull out all the strings containing a given
substring, or strip off trailing whitespace from each line.

The existing *note map(): 86a. and *note filter(): 86b. functions can be
used for this purpose, but they require a function as one of their
arguments.  This is fine if there’s an existing built-in function that
can be passed directly, but if there isn’t, you have to create a little
function to do the required work, and Python’s scoping rules make the
result ugly if the little function needs additional information.  Take
the first example in the previous paragraph, finding all the strings in
the list containing a given substring.  You could write the following to
do it:

     # Given the list L, make a list of all strings
     # containing the substring S.
     sublist = filter( lambda s, substring=S:
                          string.find(s, substring) != -1,
                       L)

Because of Python’s scoping rules, a default argument is used so that
the anonymous function created by the *note lambda: 12e4. expression
knows what substring is being searched for.  List comprehensions make
this cleaner:

     sublist = [ s for s in L if string.find(s, S) != -1 ]

List comprehensions have the form:

     [ expression for expr in sequence1
                  for expr2 in sequence2 ...
                  for exprN in sequenceN
                  if condition ]

The ‘for’…‘in’ clauses contain the sequences to be iterated over.  The
sequences do not have to be the same length, because they are 'not'
iterated over in parallel, but from left to right; this is explained
more clearly in the following paragraphs.  The elements of the generated
list will be the successive values of 'expression'.  The final ‘if’
clause is optional; if present, 'expression' is only evaluated and added
to the result if 'condition' is true.

To make the semantics very clear, a list comprehension is equivalent to
the following Python code:

     for expr1 in sequence1:
         for expr2 in sequence2:
         ...
             for exprN in sequenceN:
                  if (condition):
                       # Append the value of
                       # the expression to the
                       # resulting list.

This means that when there are multiple ‘for’…‘in’ clauses, the
resulting list will be equal to the product of the lengths of all the
sequences.  If you have two lists of length 3, the output list is 9
elements long:

     seq1 = 'abc'
     seq2 = (1,2,3)
     >>> [ (x,y) for x in seq1 for y in seq2]
     [('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('b', 3), ('c', 1),
     ('c', 2), ('c', 3)]

To avoid introducing an ambiguity into Python’s grammar, if 'expression'
is creating a tuple, it must be surrounded with parentheses.  The first
list comprehension below is a syntax error, while the second one is
correct:

     # Syntax error
     [ x,y for x in seq1 for y in seq2]
     # Correct
     [ (x,y) for x in seq1 for y in seq2]

The idea of list comprehensions originally comes from the functional
programming language Haskell (‘https://www.haskell.org’).  Greg Ewing
argued most effectively for adding them to Python and wrote the initial
list comprehension patch, which was then discussed for a seemingly
endless time on the python-dev mailing list and kept up-to-date by Skip
Montanaro.


File: python.info,  Node: Augmented Assignment,  Next: String Methods,  Prev: List Comprehensions,  Up: What’s New in Python 2 0

1.22.6 Augmented Assignment
---------------------------

Augmented assignment operators, another long-requested feature, have
been added to Python 2.0.  Augmented assignment operators include ‘+=’,
‘-=’, ‘*=’, and so forth.  For example, the statement ‘a += 2’
increments the value of the variable ‘a’ by 2, equivalent to the
slightly lengthier ‘a = a + 2’.

The full list of supported assignment operators is ‘+=’, ‘-=’, ‘*=’,
‘/=’, ‘%=’, ‘**=’, ‘&=’, ‘|=’, ‘^=’, ‘>>=’, and ‘<<=’.  Python classes
can override the augmented assignment operators by defining methods
named ‘__iadd__()’, ‘__isub__()’, etc.  For example, the following
‘Number’ class stores a number and supports using += to create a new
instance with an incremented value.

     class Number:
         def __init__(self, value):
             self.value = value
         def __iadd__(self, increment):
             return Number( self.value + increment)

     n = Number(5)
     n += 3
     print n.value

The ‘__iadd__()’ special method is called with the value of the
increment, and should return a new instance with an appropriately
modified value; this return value is bound as the new value of the
variable on the left-hand side.

Augmented assignment operators were first introduced in the C
programming language, and most C-derived languages, such as ‘awk’, C++,
Java, Perl, and PHP also support them.  The augmented assignment patch
was implemented by Thomas Wouters.


File: python.info,  Node: String Methods,  Next: Garbage Collection of Cycles,  Prev: Augmented Assignment,  Up: What’s New in Python 2 0

1.22.7 String Methods
---------------------

Until now string-manipulation functionality was in the *note string: d3.
module, which was usually a front-end for the ‘strop’ module written in
C. The addition of Unicode posed a difficulty for the ‘strop’ module,
because the functions would all need to be rewritten in order to accept
either 8-bit or Unicode strings.  For functions such as
‘string.replace()’, which takes 3 string arguments, that means eight
possible permutations, and correspondingly complicated code.

Instead, Python 2.0 pushes the problem onto the string type, making
string manipulation functionality available through methods on both
8-bit strings and Unicode strings.

     >>> 'andrew'.capitalize()
     'Andrew'
     >>> 'hostname'.replace('os', 'linux')
     'hlinuxtname'
     >>> 'moshe'.find('sh')
     2

One thing that hasn’t changed, a noteworthy April Fools’ joke
notwithstanding, is that Python strings are immutable.  Thus, the string
methods return new strings, and do not modify the string on which they
operate.

The old *note string: d3. module is still around for backwards
compatibility, but it mostly acts as a front-end to the new string
methods.

Two methods which have no parallel in pre-2.0 versions, although they
did exist in JPython for quite some time, are ‘startswith()’ and
‘endswith()’.  ‘s.startswith(t)’ is equivalent to ‘s[:len(t)] == t’,
while ‘s.endswith(t)’ is equivalent to ‘s[-len(t):] == t’.

One other method which deserves special mention is ‘join()’.  The
‘join()’ method of a string receives one parameter, a sequence of
strings, and is equivalent to the ‘string.join()’ function from the old
*note string: d3. module, with the arguments reversed.  In other words,
‘s.join(seq)’ is equivalent to the old ‘string.join(seq, s)’.


File: python.info,  Node: Garbage Collection of Cycles,  Next: Other Core Changes,  Prev: String Methods,  Up: What’s New in Python 2 0

1.22.8 Garbage Collection of Cycles
-----------------------------------

The C implementation of Python uses reference counting to implement
garbage collection.  Every Python object maintains a count of the number
of references pointing to itself, and adjusts the count as references
are created or destroyed.  Once the reference count reaches zero, the
object is no longer accessible, since you need to have a reference to an
object to access it, and if the count is zero, no references exist any
longer.

Reference counting has some pleasant properties: it’s easy to understand
and implement, and the resulting implementation is portable, fairly
fast, and reacts well with other libraries that implement their own
memory handling schemes.  The major problem with reference counting is
that it sometimes doesn’t realise that objects are no longer accessible,
resulting in a memory leak.  This happens when there are cycles of
references.

Consider the simplest possible cycle, a class instance which has a
reference to itself:

     instance = SomeClass()
     instance.myself = instance

After the above two lines of code have been executed, the reference
count of ‘instance’ is 2; one reference is from the variable named
‘'instance'’, and the other is from the ‘myself’ attribute of the
instance.

If the next line of code is ‘del instance’, what happens?  The reference
count of ‘instance’ is decreased by 1, so it has a reference count of 1;
the reference in the ‘myself’ attribute still exists.  Yet the instance
is no longer accessible through Python code, and it could be deleted.
Several objects can participate in a cycle if they have references to
each other, causing all of the objects to be leaked.

Python 2.0 fixes this problem by periodically executing a cycle
detection algorithm which looks for inaccessible cycles and deletes the
objects involved.  A new *note gc: 60. module provides functions to
perform a garbage collection, obtain debugging statistics, and tuning
the collector’s parameters.

Running the cycle detection algorithm takes some time, and therefore
will result in some additional overhead.  It is hoped that after we’ve
gotten experience with the cycle collection from using 2.0, Python 2.1
will be able to minimize the overhead with careful tuning.  It’s not yet
obvious how much performance is lost, because benchmarking this is
tricky and depends crucially on how often the program creates and
destroys objects.  The detection of cycles can be disabled when Python
is compiled, if you can’t afford even a tiny speed penalty or suspect
that the cycle collection is buggy, by specifying the
‘--without-cycle-gc’ switch when running the ‘configure’ script.

Several people tackled this problem and contributed to a solution.  An
early implementation of the cycle detection approach was written by Toby
Kelsey.  The current algorithm was suggested by Eric Tiedemann during a
visit to CNRI, and Guido van Rossum and Neil Schemenauer wrote two
different implementations, which were later integrated by Neil.  Lots of
other people offered suggestions along the way; the March 2000 archives
of the python-dev mailing list contain most of the relevant discussion,
especially in the threads titled “Reference cycle collection for Python”
and “Finalization again”.


File: python.info,  Node: Other Core Changes,  Next: Porting to 2 0,  Prev: Garbage Collection of Cycles,  Up: What’s New in Python 2 0

1.22.9 Other Core Changes
-------------------------

Various minor changes have been made to Python’s syntax and built-in
functions.  None of the changes are very far-reaching, but they’re handy
conveniences.

* Menu:

* Minor Language Changes::
* Changes to Built-in Functions::


File: python.info,  Node: Minor Language Changes,  Next: Changes to Built-in Functions,  Up: Other Core Changes

1.22.9.1 Minor Language Changes
...............................

A new syntax makes it more convenient to call a given function with a
tuple of arguments and/or a dictionary of keyword arguments.  In Python
1.5 and earlier, you’d use the ‘apply()’ built-in function: ‘apply(f,
args, kw)’ calls the function ‘f()’ with the argument tuple 'args' and
the keyword arguments in the dictionary 'kw'.  ‘apply()’ is the same in
2.0, but thanks to a patch from Greg Ewing, ‘f(*args, **kw)’ is a
shorter and clearer way to achieve the same effect.  This syntax is
symmetrical with the syntax for defining functions:

     def f(*args, **kw):
         # args is a tuple of positional args,
         # kw is a dictionary of keyword args
         ...

The ‘print’ statement can now have its output directed to a file-like
object by following the ‘print’ with ‘>> file’, similar to the
redirection operator in Unix shells.  Previously you’d either have to
use the ‘write()’ method of the file-like object, which lacks the
convenience and simplicity of ‘print’, or you could assign a new value
to ‘sys.stdout’ and then restore the old value.  For sending output to
standard error, it’s much easier to write this:

     print >> sys.stderr, "Warning: action field not supplied"

Modules can now be renamed on importing them, using the syntax ‘import
module as name’ or ‘from module import name as othername’.  The patch
was submitted by Thomas Wouters.

A new format style is available when using the ‘%’ operator; ‘%r’ will
insert the *note repr(): 803. of its argument.  This was also added from
symmetry considerations, this time for symmetry with the existing ‘%s’
format style, which inserts the *note str(): 44f. of its argument.  For
example, ‘'%r %s' % ('abc', 'abc')’ returns a string containing ‘'abc'
abc’.

Previously there was no way to implement a class that overrode Python’s
built-in *note in: 2f4. operator and implemented a custom version.  ‘obj
in seq’ returns true if 'obj' is present in the sequence 'seq'; Python
computes this by simply trying every index of the sequence until either
'obj' is found or an *note IndexError: 1585. is encountered.  Moshe
Zadka contributed a patch which adds a ‘__contains__()’ magic method for
providing a custom implementation for ‘in’.  Additionally, new built-in
objects written in C can define what ‘in’ means for them via a new slot
in the sequence protocol.

Earlier versions of Python used a recursive algorithm for deleting
objects.  Deeply nested data structures could cause the interpreter to
fill up the C stack and crash; Christian Tismer rewrote the deletion
logic to fix this problem.  On a related note, comparing recursive
objects recursed infinitely and crashed; Jeremy Hylton rewrote the code
to no longer crash, producing a useful result instead.  For example,
after this code:

     a = []
     b = []
     a.append(a)
     b.append(b)

The comparison ‘a==b’ returns true, because the two recursive data
structures are isomorphic.  See the thread “trashcan and PR#7” in the
April 2000 archives of the python-dev mailing list for the discussion
leading up to this implementation, and some useful relevant links.  Note
that comparisons can now also raise exceptions.  In earlier versions of
Python, a comparison operation such as ‘cmp(a,b)’ would always produce
an answer, even if a user-defined ‘__cmp__()’ method encountered an
error, since the resulting exception would simply be silently swallowed.

Work has been done on porting Python to 64-bit Windows on the Itanium
processor, mostly by Trent Mick of ActiveState.  (Confusingly,
‘sys.platform’ is still ‘'win32'’ on Win64 because it seems that for
ease of porting, MS Visual C++ treats code as 32 bit on Itanium.)
PythonWin also supports Windows CE; see the Python CE page at
‘https://pythonce.sourceforge.net/’ for more information.

Another new platform is Darwin/MacOS X; initial support for it is in
Python 2.0.  Dynamic loading works, if you specify “configure –with-dyld
–with-suffix=.x”.  Consult the README in the Python source distribution
for more instructions.

An attempt has been made to alleviate one of Python’s warts, the
often-confusing *note NameError: 442. exception when code refers to a
local variable before the variable has been assigned a value.  For
example, the following code raises an exception on the ‘print’ statement
in both 1.5.2 and 2.0; in 1.5.2 a ‘NameError’ exception is raised, while
2.0 raises a new *note UnboundLocalError: 1586. exception.
‘UnboundLocalError’ is a subclass of ‘NameError’, so any existing code
that expects ‘NameError’ to be raised should still work.

     def f():
         print "i=",i
         i = i + 1
     f()

Two new exceptions, *note TabError: 546. and *note IndentationError:
7ac, have been introduced.  They’re both subclasses of *note
SyntaxError: 18d, and are raised when Python code is found to be
improperly indented.


File: python.info,  Node: Changes to Built-in Functions,  Prev: Minor Language Changes,  Up: Other Core Changes

1.22.9.2 Changes to Built-in Functions
......................................

A new built-in, ‘zip(seq1, seq2, ...)’, has been added.  *note zip():
7d4. returns a list of tuples where each tuple contains the i-th element
from each of the argument sequences.  The difference between ‘zip()’ and
‘map(None, seq1, seq2)’ is that *note map(): 86a. pads the sequences
with ‘None’ if the sequences aren’t all of the same length, while
‘zip()’ truncates the returned list to the length of the shortest
argument sequence.

The *note int(): 257. and ‘long()’ functions now accept an optional
“base” parameter when the first argument is a string.  ‘int('123', 10)’
returns 123, while ‘int('123', 16)’ returns 291.  ‘int(123, 16)’ raises
a *note TypeError: 2c3. exception with the message “can’t convert
non-string with explicit base”.

A new variable holding more detailed version information has been added
to the *note sys: d9. module.  ‘sys.version_info’ is a tuple ‘(major,
minor, micro, level, serial)’ For example, in a hypothetical 2.0.1beta1,
‘sys.version_info’ would be ‘(2, 0, 1, 'beta', 1)’.  'level' is a string
such as ‘"alpha"’, ‘"beta"’, or ‘"final"’ for a final release.

Dictionaries have an odd new method, ‘setdefault(key, default)’, which
behaves similarly to the existing ‘get()’ method.  However, if the key
is missing, ‘setdefault()’ both returns the value of 'default' as
‘get()’ would do, and also inserts it into the dictionary as the value
for 'key'.  Thus, the following lines of code:

     if dict.has_key( key ): return dict[key]
     else:
         dict[key] = []
         return dict[key]

can be reduced to a single ‘return dict.setdefault(key, [])’ statement.

The interpreter sets a maximum recursion depth in order to catch runaway
recursion before filling the C stack and causing a core dump or GPF..
Previously this limit was fixed when you compiled Python, but in 2.0 the
maximum recursion depth can be read and modified using *note
sys.getrecursionlimit(): 4c7. and *note sys.setrecursionlimit(): 4c6.
The default value is 1000, and a rough maximum value for a given
platform can be found by running a new script,
‘Misc/find_recursionlimit.py’.


File: python.info,  Node: Porting to 2 0,  Next: Extending/Embedding Changes,  Prev: Other Core Changes,  Up: What’s New in Python 2 0

1.22.10 Porting to 2.0
----------------------

New Python releases try hard to be compatible with previous releases,
and the record has been pretty good.  However, some changes are
considered useful enough, usually because they fix initial design
decisions that turned out to be actively mistaken, that breaking
backward compatibility can’t always be avoided.  This section lists the
changes in Python 2.0 that may cause old Python code to break.

The change which will probably break the most code is tightening up the
arguments accepted by some methods.  Some methods would take multiple
arguments and treat them as a tuple, particularly various list methods
such as *note append(): 6d0. and *note insert(): 11dc.  In earlier
versions of Python, if ‘L’ is a list, ‘L.append( 1,2 )’ appends the
tuple ‘(1,2)’ to the list.  In Python 2.0 this causes a *note TypeError:
2c3. exception to be raised, with the message: ‘append requires exactly
1 argument; 2 given’.  The fix is to simply add an extra set of
parentheses to pass both values as a tuple: ‘L.append( (1,2) )’.

The earlier versions of these methods were more forgiving because they
used an old function in Python’s C interface to parse their arguments;
2.0 modernizes them to use *note PyArg_ParseTuple(): 574, the current
argument parsing function, which provides more helpful error messages
and treats multi-argument calls as errors.  If you absolutely must use
2.0 but can’t fix your code, you can edit ‘Objects/listobject.c’ and
define the preprocessor symbol ‘NO_STRICT_LIST_APPEND’ to preserve the
old behaviour; this isn’t recommended.

Some of the functions in the *note socket: cc. module are still
forgiving in this way.  For example, ‘socket.connect( ('hostname', 25)
)’ is the correct form, passing a tuple representing an IP address, but
‘socket.connect('hostname', 25)’ also works.  *note socket.connect_ex:
1589. and *note socket.bind: 158a. are similarly easy-going.  2.0alpha1
tightened these functions up, but because the documentation actually
used the erroneous multiple argument form, many people wrote code which
would break with the stricter checking.  GvR backed out the changes in
the face of public reaction, so for the ‘socket’ module, the
documentation was fixed and the multiple argument form is simply marked
as deprecated; it 'will' be tightened up again in a future Python
version.

The ‘\x’ escape in string literals now takes exactly 2 hex digits.
Previously it would consume all the hex digits following the ‘x’ and
take the lowest 8 bits of the result, so ‘\x123456’ was equivalent to
‘\x56’.

The *note AttributeError: 34e. and *note NameError: 442. exceptions have
a more friendly error message, whose text will be something like ‘'Spam'
instance has no attribute 'eggs'’ or ‘name 'eggs' is not defined’.
Previously the error message was just the missing attribute name ‘eggs’,
and code written to take advantage of this fact will break in 2.0.

Some work has been done to make integers and long integers a bit more
interchangeable.  In 1.5.2, large-file support was added for Solaris, to
allow reading files larger than 2 GiB; this made the ‘tell()’ method of
file objects return a long integer instead of a regular integer.  Some
code would subtract two file offsets and attempt to use the result to
multiply a sequence or slice a string, but this raised a *note
TypeError: 2c3.  In 2.0, long integers can be used to multiply or slice
a sequence, and it’ll behave as you’d intuitively expect it to; ‘3L *
'abc'’ produces ‘abcabcabc’, and ‘(0,1,2,3)[2L:4L]’ produces (2,3).
Long integers can also be used in various contexts where previously only
integers were accepted, such as in the ‘seek()’ method of file objects,
and in the formats supported by the ‘%’ operator (‘%d’, ‘%i’, ‘%x’,
etc.).  For example, ‘"%d" % 2L**64’ will produce the string
‘18446744073709551616’.

The subtlest long integer change of all is that the *note str(): 44f. of
a long integer no longer has a trailing ‘L’ character, though *note
repr(): 803. still includes it.  The ‘L’ annoyed many people who wanted
to print long integers that looked just like regular integers, since
they had to go out of their way to chop off the character.  This is no
longer a problem in 2.0, but code which does ‘str(longval)[:-1]’ and
assumes the ‘L’ is there, will now lose the final digit.

Taking the *note repr(): 803. of a float now uses a different formatting
precision than *note str(): 44f.  ‘repr()’ uses ‘%.17g’ format string
for C’s ‘sprintf()’, while ‘str()’ uses ‘%.12g’ as before.  The effect
is that ‘repr()’ may occasionally show more decimal places than ‘str()’,
for certain numbers.  For example, the number 8.1 can’t be represented
exactly in binary, so ‘repr(8.1)’ is ‘'8.0999999999999996'’, while
str(8.1) is ‘'8.1'’.

The ‘-X’ command-line option, which turned all standard exceptions into
strings instead of classes, has been removed; the standard exceptions
will now always be classes.  The ‘exceptions’ module containing the
standard exceptions was translated from Python to a built-in C module,
written by Barry Warsaw and Fredrik Lundh.


File: python.info,  Node: Extending/Embedding Changes,  Next: Distutils Making Modules Easy to Install,  Prev: Porting to 2 0,  Up: What’s New in Python 2 0

1.22.11 Extending/Embedding Changes
-----------------------------------

Some of the changes are under the covers, and will only be apparent to
people writing C extension modules or embedding a Python interpreter in
a larger application.  If you aren’t dealing with Python’s C API, you
can safely skip this section.

The version number of the Python C API was incremented, so C extensions
compiled for 1.5.2 must be recompiled in order to work with 2.0.  On
Windows, it’s not possible for Python 2.0 to import a third party
extension built for Python 1.5.x due to how Windows DLLs work, so Python
will raise an exception and the import will fail.

Users of Jim Fulton’s ExtensionClass module will be pleased to find out
that hooks have been added so that ExtensionClasses are now supported by
*note isinstance(): 445. and *note issubclass(): 7c5.  This means you no
longer have to remember to write code such as ‘if type(obj) ==
myExtensionClass’, but can use the more natural ‘if isinstance(obj,
myExtensionClass)’.

The ‘Python/importdl.c’ file, which was a mass of #ifdefs to support
dynamic loading on many different platforms, was cleaned up and
reorganised by Greg Stein.  ‘importdl.c’ is now quite small, and
platform-specific code has been moved into a bunch of
‘Python/dynload_*.c’ files.  Another cleanup: there were also a number
of ‘my*.h’ files in the Include/ directory that held various portability
hacks; they’ve been merged into a single file, ‘Include/pyport.h’.

Vladimir Marangozov’s long-awaited malloc restructuring was completed,
to make it easy to have the Python interpreter use a custom allocator
instead of C’s standard ‘malloc()’.  For documentation, read the
comments in ‘Include/pymem.h’ and ‘Include/objimpl.h’.  For the lengthy
discussions during which the interface was hammered out, see the web
archives of the ‘patches’ and ‘python-dev’ lists at python.org.

Recent versions of the GUSI development environment for MacOS support
POSIX threads.  Therefore, Python’s POSIX threading support now works on
the Macintosh.  Threading support using the user-space GNU ‘pth’ library
was also contributed.

Threading support on Windows was enhanced, too.  Windows supports thread
locks that use kernel objects only in case of contention; in the common
case when there’s no contention, they use simpler functions which are an
order of magnitude faster.  A threaded version of Python 1.5.2 on NT is
twice as slow as an unthreaded version; with the 2.0 changes, the
difference is only 10%.  These improvements were contributed by Yakov
Markovitch.

Python 2.0’s source now uses only ANSI C prototypes, so compiling Python
now requires an ANSI C compiler, and can no longer be done using a
compiler that only supports K&R C.

Previously the Python virtual machine used 16-bit numbers in its
bytecode, limiting the size of source files.  In particular, this
affected the maximum size of literal lists and dictionaries in Python
source; occasionally people who are generating Python code would run
into this limit.  A patch by Charles G. Waldman raises the limit from
‘2**16’ to ‘2**32’.

Three new convenience functions intended for adding constants to a
module’s dictionary at module initialization time were added: *note
PyModule_AddObject(): 369, *note PyModule_AddIntConstant(): 158c, and
*note PyModule_AddStringConstant(): 158d.  Each of these functions takes
a module object, a null-terminated C string containing the name to be
added, and a third argument for the value to be assigned to the name.
This third argument is, respectively, a Python object, a C long, or a C
string.

A wrapper API was added for Unix-style signal handlers.  *note
PyOS_getsig(): 158e. gets a signal handler and *note PyOS_setsig():
158f. will set a new handler.


File: python.info,  Node: Distutils Making Modules Easy to Install,  Next: XML Modules,  Prev: Extending/Embedding Changes,  Up: What’s New in Python 2 0

1.22.12 Distutils: Making Modules Easy to Install
-------------------------------------------------

Before Python 2.0, installing modules was a tedious affair – there was
no way to figure out automatically where Python is installed, or what
compiler options to use for extension modules.  Software authors had to
go through an arduous ritual of editing Makefiles and configuration
files, which only really work on Unix and leave Windows and MacOS
unsupported.  Python users faced wildly differing installation
instructions which varied between different extension packages, which
made administering a Python installation something of a chore.

The SIG for distribution utilities, shepherded by Greg Ward, has created
the Distutils, a system to make package installation much easier.  They
form the ‘distutils’ package, a new part of Python’s standard library.
In the best case, installing a Python module from source will require
the same steps: first you simply mean unpack the tarball or zip archive,
and the run “‘python setup.py install’”.  The platform will be
automatically detected, the compiler will be recognized, C extension
modules will be compiled, and the distribution installed into the proper
directory.  Optional command-line arguments provide more control over
the installation process, the distutils package offers many places to
override defaults – separating the build from the install, building or
installing in non-default directories, and more.

In order to use the Distutils, you need to write a ‘setup.py’ script.
For the simple case, when the software contains only .py files, a
minimal ‘setup.py’ can be just a few lines long:

     from distutils.core import setup
     setup (name = "foo", version = "1.0",
            py_modules = ["module1", "module2"])

The ‘setup.py’ file isn’t much more complicated if the software consists
of a few packages:

     from distutils.core import setup
     setup (name = "foo", version = "1.0",
            packages = ["package", "package.subpackage"])

A C extension can be the most complicated case; here’s an example taken
from the PyXML package:

     from distutils.core import setup, Extension

     expat_extension = Extension('xml.parsers.pyexpat',
          define_macros = [('XML_NS', None)],
          include_dirs = [ 'extensions/expat/xmltok',
                           'extensions/expat/xmlparse' ],
          sources = [ 'extensions/pyexpat.c',
                      'extensions/expat/xmltok/xmltok.c',
                      'extensions/expat/xmltok/xmlrole.c', ]
            )
     setup (name = "PyXML", version = "0.5.4",
            ext_modules =[ expat_extension ] )

The Distutils can also take care of creating source and binary
distributions.  The “sdist” command, run by “‘python setup.py sdist’’,
builds a source distribution such as ‘foo-1.0.tar.gz’.  Adding new
commands isn’t difficult, “bdist_rpm” and “bdist_wininst” commands have
already been contributed to create an RPM distribution and a Windows
installer for the software, respectively.  Commands to create other
distribution formats such as Debian packages and Solaris ‘.pkg’ files
are in various stages of development.

All this is documented in a new manual, 'Distributing Python Modules',
that joins the basic set of Python documentation.


File: python.info,  Node: XML Modules,  Next: Module changes,  Prev: Distutils Making Modules Easy to Install,  Up: What’s New in Python 2 0

1.22.13 XML Modules
-------------------

Python 1.5.2 included a simple XML parser in the form of the ‘xmllib’
module, contributed by Sjoerd Mullender.  Since 1.5.2’s release, two
different interfaces for processing XML have become common: SAX2
(version 2 of the Simple API for XML) provides an event-driven interface
with some similarities to ‘xmllib’, and the DOM (Document Object Model)
provides a tree-based interface, transforming an XML document into a
tree of nodes that can be traversed and modified.  Python 2.0 includes a
SAX2 interface and a stripped-down DOM interface as part of the *note
xml: 120. package.  Here we will give a brief overview of these new
interfaces; consult the Python documentation or the source code for
complete details.  The Python XML SIG is also working on improved
documentation.

* Menu:

* SAX2 Support::
* DOM Support::
* Relationship to PyXML::


File: python.info,  Node: SAX2 Support,  Next: DOM Support,  Up: XML Modules

1.22.13.1 SAX2 Support
......................

SAX defines an event-driven interface for parsing XML. To use SAX, you
must write a SAX handler class.  Handler classes inherit from various
classes provided by SAX, and override various methods that will then be
called by the XML parser.  For example, the *note startElement(): 1593.
and *note endElement(): 1594. methods are called for every starting and
end tag encountered by the parser, the *note characters(): 1595. method
is called for every chunk of character data, and so forth.

The advantage of the event-driven approach is that the whole document
doesn’t have to be resident in memory at any one time, which matters if
you are processing really huge documents.  However, writing the SAX
handler class can get very complicated if you’re trying to modify the
document structure in some elaborate way.

For example, this little example program defines a handler that prints a
message for every starting and ending tag, and then parses the file
‘hamlet.xml’ using it:

     from xml import sax

     class SimpleHandler(sax.ContentHandler):
         def startElement(self, name, attrs):
             print 'Start of element:', name, attrs.keys()

         def endElement(self, name):
             print 'End of element:', name

     # Create a parser object
     parser = sax.make_parser()

     # Tell it what handler to use
     handler = SimpleHandler()
     parser.setContentHandler( handler )

     # Parse a file!
     parser.parse( 'hamlet.xml' )

For more information, consult the Python documentation, or the XML HOWTO
at ‘https://pyxml.sourceforge.net/topics/howto/xml-howto.html’.


File: python.info,  Node: DOM Support,  Next: Relationship to PyXML,  Prev: SAX2 Support,  Up: XML Modules

1.22.13.2 DOM Support
.....................

The Document Object Model is a tree-based representation for an XML
document.  A top-level ‘Document’ instance is the root of the tree, and
has a single child which is the top-level ‘Element’ instance.  This
‘Element’ has children nodes representing character data and any
sub-elements, which may have further children of their own, and so
forth.  Using the DOM you can traverse the resulting tree any way you
like, access element and attribute values, insert and delete nodes, and
convert the tree back into XML.

The DOM is useful for modifying XML documents, because you can create a
DOM tree, modify it by adding new nodes or rearranging subtrees, and
then produce a new XML document as output.  You can also construct a DOM
tree manually and convert it to XML, which can be a more flexible way of
producing XML output than simply writing ‘<tag1>’…‘</tag1>’ to a file.

The DOM implementation included with Python lives in the *note
xml.dom.minidom: 122. module.  It’s a lightweight implementation of the
Level 1 DOM with support for XML namespaces.  The ‘parse()’ and
‘parseString()’ convenience functions are provided for generating a DOM
tree:

     from xml.dom import minidom
     doc = minidom.parse('hamlet.xml')

‘doc’ is a ‘Document’ instance.  ‘Document’, like all the other DOM
classes such as ‘Element’ and ‘Text’, is a subclass of the ‘Node’ base
class.  All the nodes in a DOM tree therefore support certain common
methods, such as ‘toxml()’ which returns a string containing the XML
representation of the node and its children.  Each class also has
special methods of its own; for example, ‘Element’ and ‘Document’
instances have a method to find all child elements with a given tag
name.  Continuing from the previous 2-line example:

     perslist = doc.getElementsByTagName( 'PERSONA' )
     print perslist[0].toxml()
     print perslist[1].toxml()

For the 'Hamlet' XML file, the above few lines output:

     <PERSONA>CLAUDIUS, king of Denmark. </PERSONA>
     <PERSONA>HAMLET, son to the late, and nephew to the present king.</PERSONA>

The root element of the document is available as ‘doc.documentElement’,
and its children can be easily modified by deleting, adding, or removing
nodes:

     root = doc.documentElement

     # Remove the first child
     root.removeChild( root.childNodes[0] )

     # Move the new first child to the end
     root.appendChild( root.childNodes[0] )

     # Insert the new first child (originally,
     # the third child) before the 20th child.
     root.insertBefore( root.childNodes[0], root.childNodes[20] )

Again, I will refer you to the Python documentation for a complete
listing of the different ‘Node’ classes and their various methods.


File: python.info,  Node: Relationship to PyXML,  Prev: DOM Support,  Up: XML Modules

1.22.13.3 Relationship to PyXML
...............................

The XML Special Interest Group has been working on XML-related Python
code for a while.  Its code distribution, called PyXML, is available
from the SIG’s web pages at
‘https://www.python.org/community/sigs/current/xml-sig’.  The PyXML
distribution also used the package name ‘xml’.  If you’ve written
programs that used PyXML, you’re probably wondering about its
compatibility with the 2.0 *note xml: 120. package.

The answer is that Python 2.0’s *note xml: 120. package isn’t compatible
with PyXML, but can be made compatible by installing a recent version
PyXML. Many applications can get by with the XML support that is
included with Python 2.0, but more complicated applications will require
that the full PyXML package will be installed.  When installed, PyXML
versions 0.6.0 or greater will replace the ‘xml’ package shipped with
Python, and will be a strict superset of the standard package, adding a
bunch of additional features.  Some of the additional features in PyXML
include:

   * 4DOM, a full DOM implementation from FourThought, Inc.

   * The xmlproc validating parser, written by Lars Marius Garshol.

   * The ‘sgmlop’ parser accelerator module, written by Fredrik Lundh.


File: python.info,  Node: Module changes,  Next: New modules,  Prev: XML Modules,  Up: What’s New in Python 2 0

1.22.14 Module changes
----------------------

Lots of improvements and bugfixes were made to Python’s extensive
standard library; some of the affected modules include *note readline:
ba, *note ConfigParser: 22, ‘cgi’, *note calendar: 14, *note posix: ad,
‘readline’, ‘xmllib’, ‘aifc’, ‘chunk’, *note wave: 113, *note random:
b8, *note shelve: c3, and ‘nntplib’.  Consult the CVS logs for the exact
patch-by-patch details.

Brian Gallew contributed OpenSSL support for the *note socket: cc.
module.  OpenSSL is an implementation of the Secure Socket Layer, which
encrypts the data being sent over a socket.  When compiling Python, you
can edit ‘Modules/Setup’ to include SSL support, which adds an
additional function to the ‘socket’ module: ‘socket.ssl(socket, keyfile,
certfile)’, which takes a socket object and returns an SSL socket.  The
*note httplib: 6e. and *note urllib: 108. modules were also changed to
support ‘https://’ URLs, though no one has implemented FTP or SMTP over
SSL.

The *note httplib: 6e. module has been rewritten by Greg Stein to
support HTTP/1.1.

Backward compatibility with the 1.5 version of ‘httplib’ is provided,
though using HTTP/1.1 features such as pipelining will require rewriting
code to use a different set of interfaces.

The ‘Tkinter’ module now supports Tcl/Tk version 8.1, 8.2, or 8.3, and
support for the older 7.x versions has been dropped.  The Tkinter module
now supports displaying Unicode strings in Tk widgets.  Also, Fredrik
Lundh contributed an optimization which makes operations like
‘create_line’ and ‘create_polygon’ much faster, especially when using
lots of coordinates.

The *note curses: 2b. module has been greatly extended, starting from
Oliver Andrich’s enhanced version, to provide many additional functions
from ncurses and SYSV curses, such as colour, alternative character set
support, pads, and mouse support.  This means the module is no longer
compatible with operating systems that only have BSD curses, but there
don’t seem to be any currently maintained OSes that fall into this
category.

As mentioned in the earlier discussion of 2.0’s Unicode support, the
underlying implementation of the regular expressions provided by the
*note re: b9. module has been changed.  SRE, a new regular expression
engine written by Fredrik Lundh and partially funded by Hewlett Packard,
supports matching against both 8-bit strings and Unicode strings.


File: python.info,  Node: New modules,  Next: IDLE Improvements,  Prev: Module changes,  Up: What’s New in Python 2 0

1.22.15 New modules
-------------------

A number of new modules were added.  We’ll simply list them with brief
descriptions; consult the 2.0 documentation for the details of a
particular module.

   * *note atexit: c.: For registering functions to be called before the
     Python interpreter exits.  Code that currently sets ‘sys.exitfunc’
     directly should be changed to use the ‘atexit’ module instead,
     importing ‘atexit’ and calling *note atexit.register(): 885. with
     the function to be called on exit.  (Contributed by Skip
     Montanaro.)

   * *note codecs: 1b, ‘encodings’, *note unicodedata: 105.: Added as
     part of the new Unicode support.

   * *note filecmp: 5a.: Supersedes the old ‘cmp’, ‘cmpcache’ and
     ‘dircmp’ modules, which have now become deprecated.  (Contributed
     by Gordon MacMillan and Moshe Zadka.)

   * *note gettext: 63.: This module provides internationalization
     (I18N) and localization (L10N) support for Python programs by
     providing an interface to the GNU gettext message catalog library.
     (Integrated by Barry Warsaw, from separate contributions by Martin
     von Löwis, Peter Funk, and James Henstridge.)

   * ‘linuxaudiodev’: Support for the ‘/dev/audio’ device on Linux, a
     twin to the existing ‘sunaudiodev’ module.  (Contributed by Peter
     Bosch, with fixes by Jeremy Hylton.)

   * *note mmap: 90.: An interface to memory-mapped files on both
     Windows and Unix.  A file’s contents can be mapped directly into
     memory, at which point it behaves like a mutable string, so its
     contents can be read and modified.  They can even be passed to
     functions that expect ordinary strings, such as the *note re: b9.
     module.  (Contributed by Sam Rushing, with some extensions by A.M.
     Kuchling.)

   * ‘pyexpat’: An interface to the Expat XML parser.  (Contributed by
     Paul Prescod.)

   * *note robotparser: 10d.: Parse a ‘robots.txt’ file, which is used
     for writing web spiders that politely avoid certain areas of a web
     site.  The parser accepts the contents of a ‘robots.txt’ file,
     builds a set of rules from it, and can then answer questions about
     the fetchability of a given URL. (Contributed by Skip Montanaro.)

   * *note tabnanny: dd.: A module/script to check Python source code
     for ambiguous indentation.  (Contributed by Tim Peters.)

   * ‘UserString’: A base class useful for deriving objects that behave
     like strings.

   * *note webbrowser: 115.: A module that provides a platform
     independent way to launch a web browser on a specific URL. For each
     platform, various browsers are tried in a specific order.  The user
     can alter which browser is launched by setting the 'BROWSER'
     environment variable.  (Originally inspired by Eric S. Raymond’s
     patch to *note urllib: 108. which added similar functionality, but
     the final module comes from code originally implemented by Fred
     Drake as ‘Tools/idle/BrowserControl.py’, and adapted for the
     standard library by Fred.)

   * *note _winreg: 116.: An interface to the Windows registry.
     ‘_winreg’ is an adaptation of functions that have been part of
     PythonWin since 1995, but has now been added to the core
     distribution, and enhanced to support Unicode.  ‘_winreg’ was
     written by Bill Tutt and Mark Hammond.

   * *note zipfile: 131.: A module for reading and writing ZIP-format
     archives.  These are archives produced by ‘PKZIP’ on DOS/Windows or
     ‘zip’ on Unix, not to be confused with ‘gzip’-format files (which
     are supported by the *note gzip: 67. module) (Contributed by James
     C. Ahlstrom.)

   * ‘imputil’: A module that provides a simpler way for writing
     customized import hooks, in comparison to the existing ‘ihooks’
     module.  (Implemented by Greg Stein, with much discussion on
     python-dev along the way.)


File: python.info,  Node: IDLE Improvements,  Next: Deleted and Deprecated Modules,  Prev: New modules,  Up: What’s New in Python 2 0

1.22.16 IDLE Improvements
-------------------------

IDLE is the official Python cross-platform IDE, written using Tkinter.
Python 2.0 includes IDLE 0.6, which adds a number of new features and
improvements.  A partial list:

   * UI improvements and optimizations, especially in the area of syntax
     highlighting and auto-indentation.

   * The class browser now shows more information, such as the top level
     functions in a module.

   * Tab width is now a user settable option.  When opening an existing
     Python file, IDLE automatically detects the indentation
     conventions, and adapts.

   * There is now support for calling browsers on various platforms,
     used to open the Python documentation in a browser.

   * IDLE now has a command line, which is largely similar to the
     vanilla Python interpreter.

   * Call tips were added in many places.

   * IDLE can now be installed as a package.

   * In the editor window, there is now a line/column bar at the bottom.

   * Three new keystroke commands: Check module (‘Alt’-‘F5’), Import
     module (‘F5’) and Run script (‘Ctrl’-‘F5’).


File: python.info,  Node: Deleted and Deprecated Modules,  Next: Acknowledgements<8>,  Prev: IDLE Improvements,  Up: What’s New in Python 2 0

1.22.17 Deleted and Deprecated Modules
--------------------------------------

A few modules have been dropped because they’re obsolete, or because
there are now better ways to do the same thing.  The ‘stdwin’ module is
gone; it was for a platform-independent windowing toolkit that’s no
longer developed.

A number of modules have been moved to the ‘lib-old’ subdirectory:
‘cmp’, ‘cmpcache’, ‘dircmp’, ‘dump’, ‘find’, ‘grep’, ‘packmail’, ‘poly’,
‘util’, ‘whatsound’, ‘zmod’.  If you have code which relies on a module
that’s been moved to ‘lib-old’, you can simply add that directory to
‘sys.path’ to get them back, but you’re encouraged to update any code
that uses these modules.


File: python.info,  Node: Acknowledgements<8>,  Prev: Deleted and Deprecated Modules,  Up: What’s New in Python 2 0

1.22.18 Acknowledgements
------------------------

The authors would like to thank the following people for offering
suggestions on various drafts of this article: David Bolen, Mark
Hammond, Gregg Hauser, Jeremy Hylton, Fredrik Lundh, Detlef Lannert,
Aahz Maruch, Skip Montanaro, Vladimir Marangozov, Tobias Polzin, Guido
van Rossum, Neil Schemenauer, and Russ Schmidt.

The “Changelog” is an HTML version of the file built(1) from the
contents of the Misc/NEWS.d(2) directory tree, which contains 'all'
nontrivial changes to Python for the current version.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/blurb/

   (2) https://github.com/python/cpython/tree/3.13/Misc/NEWS.d


File: python.info,  Node: Changelog,  Prev: What’s New in Python 2 0,  Up: What’s New in Python

1.23 Changelog
==============

* Menu:

* Python 3.13.13 final: Python 3 13 13 final.
* Python 3.13.12 final: Python 3 13 12 final.
* Python 3.13.11 final: Python 3 13 11 final.
* Python 3.13.10 final: Python 3 13 10 final.
* Python 3.13.9 final: Python 3 13 9 final.
* Python 3.13.8 final: Python 3 13 8 final.
* Python 3.13.7 final: Python 3 13 7 final.
* Python 3.13.6 final: Python 3 13 6 final.
* Python 3.13.5 final: Python 3 13 5 final.
* Python 3.13.4 final: Python 3 13 4 final.
* Python 3.13.3 final: Python 3 13 3 final.
* Python 3.13.2 final: Python 3 13 2 final.
* Python 3.13.1 final: Python 3 13 1 final.
* Python 3.13.0 final: Python 3 13 0 final.
* Python 3.13.0 release candidate 3: Python 3 13 0 release candidate 3.
* Python 3.13.0 release candidate 2: Python 3 13 0 release candidate 2.
* Python 3.13.0 release candidate 1: Python 3 13 0 release candidate 1.
* Python 3.13.0 beta 4: Python 3 13 0 beta 4.
* Python 3.13.0 beta 3: Python 3 13 0 beta 3.
* Python 3.13.0 beta 2: Python 3 13 0 beta 2.
* Python 3.13.0 beta 1: Python 3 13 0 beta 1.
* Python 3.13.0 alpha 6: Python 3 13 0 alpha 6.
* Python 3.13.0 alpha 5: Python 3 13 0 alpha 5.
* Python 3.13.0 alpha 4: Python 3 13 0 alpha 4.
* Python 3.13.0 alpha 3: Python 3 13 0 alpha 3.
* Python 3.13.0 alpha 2: Python 3 13 0 alpha 2.
* Python 3.13.0 alpha 1: Python 3 13 0 alpha 1.
* Python 3.12.0 beta 1: Python 3 12 0 beta 1.
* Python 3.12.0 alpha 7: Python 3 12 0 alpha 7.
* Python 3.12.0 alpha 6: Python 3 12 0 alpha 6.
* Python 3.12.0 alpha 5: Python 3 12 0 alpha 5.
* Python 3.12.0 alpha 4: Python 3 12 0 alpha 4.
* Python 3.12.0 alpha 3: Python 3 12 0 alpha 3.
* Python 3.12.0 alpha 2: Python 3 12 0 alpha 2.
* Python 3.12.0 alpha 1: Python 3 12 0 alpha 1.
* Python 3.11.0 beta 1: Python 3 11 0 beta 1.
* Python 3.11.0 alpha 7: Python 3 11 0 alpha 7.
* Python 3.11.0 alpha 6: Python 3 11 0 alpha 6.
* Python 3.11.0 alpha 5: Python 3 11 0 alpha 5.
* Python 3.11.0 alpha 4: Python 3 11 0 alpha 4.
* Python 3.11.0 alpha 3: Python 3 11 0 alpha 3.
* Python 3.11.0 alpha 2: Python 3 11 0 alpha 2.
* Python 3.11.0 alpha 1: Python 3 11 0 alpha 1.
* Python 3.10.0 beta 1: Python 3 10 0 beta 1.
* Python 3.10.0 alpha 7: Python 3 10 0 alpha 7.
* Python 3.10.0 alpha 6: Python 3 10 0 alpha 6.
* Python 3.10.0 alpha 5: Python 3 10 0 alpha 5.
* Python 3.10.0 alpha 4: Python 3 10 0 alpha 4.
* Python 3.10.0 alpha 3: Python 3 10 0 alpha 3.
* Python 3.10.0 alpha 2: Python 3 10 0 alpha 2.
* Python 3.10.0 alpha 1: Python 3 10 0 alpha 1.
* Python 3.9.0 beta 1: Python 3 9 0 beta 1.
* Python 3.9.0 alpha 6: Python 3 9 0 alpha 6.
* Python 3.9.0 alpha 5: Python 3 9 0 alpha 5.
* Python 3.9.0 alpha 4: Python 3 9 0 alpha 4.
* Python 3.9.0 alpha 3: Python 3 9 0 alpha 3.
* Python 3.9.0 alpha 2: Python 3 9 0 alpha 2.
* Python 3.9.0 alpha 1: Python 3 9 0 alpha 1.
* Python 3.8.0 beta 1: Python 3 8 0 beta 1.
* Python 3.8.0 alpha 4: Python 3 8 0 alpha 4.
* Python 3.8.0 alpha 3: Python 3 8 0 alpha 3.
* Python 3.8.0 alpha 2: Python 3 8 0 alpha 2.
* Python 3.8.0 alpha 1: Python 3 8 0 alpha 1.
* Python 3.7.0 final: Python 3 7 0 final.
* Python 3.7.0 release candidate 1: Python 3 7 0 release candidate 1.
* Python 3.7.0 beta 5: Python 3 7 0 beta 5.
* Python 3.7.0 beta 4: Python 3 7 0 beta 4.
* Python 3.7.0 beta 3: Python 3 7 0 beta 3.
* Python 3.7.0 beta 2: Python 3 7 0 beta 2.
* Python 3.7.0 beta 1: Python 3 7 0 beta 1.
* Python 3.7.0 alpha 4: Python 3 7 0 alpha 4.
* Python 3.7.0 alpha 3: Python 3 7 0 alpha 3.
* Python 3.7.0 alpha 2: Python 3 7 0 alpha 2.
* Python 3.7.0 alpha 1: Python 3 7 0 alpha 1.
* Python 3.6.6 final: Python 3 6 6 final.
* Python 3.6.6 release candidate 1: Python 3 6 6 release candidate 1.
* Python 3.6.5 final: Python 3 6 5 final.
* Python 3.6.5 release candidate 1: Python 3 6 5 release candidate 1.
* Python 3.6.4 final: Python 3 6 4 final.
* Python 3.6.4 release candidate 1: Python 3 6 4 release candidate 1.
* Python 3.6.3 final: Python 3 6 3 final.
* Python 3.6.3 release candidate 1: Python 3 6 3 release candidate 1.
* Python 3.6.2 final: Python 3 6 2 final.
* Python 3.6.2 release candidate 2: Python 3 6 2 release candidate 2.
* Python 3.6.2 release candidate 1: Python 3 6 2 release candidate 1.
* Python 3.6.1 final: Python 3 6 1 final.
* Python 3.6.1 release candidate 1: Python 3 6 1 release candidate 1.
* Python 3.6.0 final: Python 3 6 0 final.
* Python 3.6.0 release candidate 2: Python 3 6 0 release candidate 2.
* Python 3.6.0 release candidate 1: Python 3 6 0 release candidate 1.
* Python 3.6.0 beta 4: Python 3 6 0 beta 4.
* Python 3.6.0 beta 3: Python 3 6 0 beta 3.
* Python 3.6.0 beta 2: Python 3 6 0 beta 2.
* Python 3.6.0 beta 1: Python 3 6 0 beta 1.
* Python 3.6.0 alpha 4: Python 3 6 0 alpha 4.
* Python 3.6.0 alpha 3: Python 3 6 0 alpha 3.
* Python 3.6.0 alpha 2: Python 3 6 0 alpha 2.
* Python 3.6.0 alpha 1: Python 3 6 0 alpha 1.
* Python 3.5.5 final: Python 3 5 5 final.
* Python 3.5.5 release candidate 1: Python 3 5 5 release candidate 1.
* Python 3.5.4 final: Python 3 5 4 final.
* Python 3.5.4 release candidate 1: Python 3 5 4 release candidate 1.
* Python 3.5.3 final: Python 3 5 3 final.
* Python 3.5.3 release candidate 1: Python 3 5 3 release candidate 1.
* Python 3.5.2 final: Python 3 5 2 final.
* Python 3.5.2 release candidate 1: Python 3 5 2 release candidate 1.
* Python 3.5.1 final: Python 3 5 1 final.
* Python 3.5.1 release candidate 1: Python 3 5 1 release candidate 1.
* Python 3.5.0 final: Python 3 5 0 final.
* Python 3.5.0 release candidate 4: Python 3 5 0 release candidate 4.
* Python 3.5.0 release candidate 3: Python 3 5 0 release candidate 3.
* Python 3.5.0 release candidate 2: Python 3 5 0 release candidate 2.
* Python 3.5.0 release candidate 1: Python 3 5 0 release candidate 1.
* Python 3.5.0 beta 4: Python 3 5 0 beta 4.
* Python 3.5.0 beta 3: Python 3 5 0 beta 3.
* Python 3.5.0 beta 2: Python 3 5 0 beta 2.
* Python 3.5.0 beta 1: Python 3 5 0 beta 1.
* Python 3.5.0 alpha 4: Python 3 5 0 alpha 4.
* Python 3.5.0 alpha 3: Python 3 5 0 alpha 3.
* Python 3.5.0 alpha 2: Python 3 5 0 alpha 2.
* Python 3.5.0 alpha 1: Python 3 5 0 alpha 1.


File: python.info,  Node: Python 3 13 13 final,  Next: Python 3 13 12 final,  Up: Changelog

1.23.1 Python 3.13.13 final
---------------------------

'Release date: 2026-04-07'

* Menu:

* macOS::
* Windows::
* Tests::
* Security::
* Library::
* Documentation: Documentation<2>.
* Core and Builtins::
* Build::


File: python.info,  Node: macOS,  Next: Windows,  Up: Python 3 13 13 final

1.23.1.1 macOS
..............

   - gh-144551(1): Update macOS installer to use OpenSSL 3.0.19.

   - gh-137586(2): Invoke ‘osascript’ with absolute path in *note
     webbrowser: 115. and ‘turtledemo’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144551

   (2) https://github.com/python/cpython/issues/137586


File: python.info,  Node: Windows,  Next: Tests,  Prev: macOS,  Up: Python 3 13 13 final

1.23.1.2 Windows
................

   - gh-144551(1): Updated bundled version of OpenSSL to 3.0.19.

   - gh-140131(2): Fix REPL cursor position on Windows when module
     completion suggestion line hits console width.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144551

   (2) https://github.com/python/cpython/issues/140131


File: python.info,  Node: Tests,  Next: Security,  Prev: Windows,  Up: Python 3 13 13 final

1.23.1.3 Tests
..............

   - gh-144418(1): The Android testbed’s emulator RAM has been increased
     from 2 GB to 4 GB.

   - gh-146202(2): Fix a race condition in regrtest: make sure that the
     temporary directory is created in the worker process.  Previously,
     temp_cwd() could fail on Windows if the “build” directory was not
     created.  Patch by Victor Stinner.

   - gh-144739(3): When Python was compiled with system expat older then
     2.7.2 but tests run with newer expat, still skip
     ‘test.test_pyexpat.MemoryProtectionTest’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144418

   (2) https://github.com/python/cpython/issues/146202

   (3) https://github.com/python/cpython/issues/144739


File: python.info,  Node: Security,  Next: Library,  Prev: Tests,  Up: Python 3 13 13 final

1.23.1.4 Security
.................

   - gh-145986(1): *note xml.parsers.expat: 126.: Fixed a crash caused
     by unbounded C recursion when converting deeply nested XML content
     models with *note ElementDeclHandler(): 15a5.  This addresses CVE
     2026-4224(2).

   - gh-145599(3): Reject control characters in *note
     http.cookies.Morsel: c24. *note update(): efd. and *note
     js_output(): 15a6.  This addresses CVE 2026-3644(4).

   - gh-145506(5): Fixes CVE 2026-2297(6) by ensuring that
     ‘SourcelessFileLoader’ uses *note io.open_code(): 15a7. when
     opening ‘.pyc’ files.

   - gh-144370(7): Disallow usage of control characters in status in
     *note wsgiref.handlers: 119. to prevent HTTP header injections.
     Patch by Benedikt Johannes.

   - gh-143930(8): Reject leading dashes in URLs passed to *note
     webbrowser.open(): 15a8.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/145986

   (2) https://www.cve.org/CVERecord?id=CVE-2026-4224

   (3) https://github.com/python/cpython/issues/145599

   (4) https://www.cve.org/CVERecord?id=CVE-2026-3644

   (5) https://github.com/python/cpython/issues/145506

   (6) https://www.cve.org/CVERecord?id=CVE-2026-2297

   (7) https://github.com/python/cpython/issues/144370

   (8) https://github.com/python/cpython/issues/143930


File: python.info,  Node: Library,  Next: Documentation<2>,  Prev: Security,  Up: Python 3 13 13 final

1.23.1.5 Library
................

   - gh-144503(1): Fix a regression introduced in 3.14.3 and 3.13.12
     where the *note multiprocessing: 94. ‘forkserver’ start method
     would fail with *note BrokenPipeError: 109a. when the parent
     process had a very large *note sys.argv: 12ab.  The argv is now
     passed to the forkserver as separate command-line arguments rather
     than being embedded in the ‘-c’ command string, avoiding the
     operating system’s per-argument length limit.

   - gh-146613(2): *note itertools: 81.: Fix a crash in *note
     itertools.groupby(): 15aa. when the grouper iterator is
     concurrently mutated.

   - gh-146080(3): *note ssl: d0.: fix a crash when an SNI callback
     tries to use an SSL object that has already been garbage-collected.
     Patch by Bénédikt Tran.

   - gh-146090(4): *note sqlite3: cf.: fix a crash when *note
     sqlite3.Connection.create_collation(): 679. fails with
     SQLITE_BUSY(5).  Patch by Bénédikt Tran.

   - gh-146090(6): *note sqlite3: cf.: properly raise *note MemoryError:
     15ab. instead of *note SystemError: 578. when a context callback
     fails to be allocated.  Patch by Bénédikt Tran.

   - gh-145633(7): Fix ‘struct.pack('f', float)’: use *note
     PyFloat_Pack4(): 769. to raise *note OverflowError: 888.  Patch by
     Sergey B Kirpichev and Victor Stinner.

   - gh-146310(8): The *note ensurepip: 55. module no longer looks for
     ‘pip-*.whl’ wheel packages in the current directory.

   - gh-146083(9): Update bundled libexpat(10) to version 2.7.5.

   - gh-146076(11): *note zoneinfo: 134.: fix crashes when deleting
     ‘_weak_cache’ from a *note zoneinfo.ZoneInfo: 8e8. subclass.

   - gh-146054(12): Limit the size of *note encodings.search_function():
     15ac. cache.  Found by OSS Fuzz in #493449985(13).

   - gh-145883(14): *note zoneinfo: 134.: Fix heap buffer overflow reads
     from malformed TZif data.  Found by OSS Fuzz, issues #492245058(15)
     and #492230068(16).

   - gh-145750(17): Avoid undefined behaviour from signed integer
     overflow when parsing format strings in the *note struct: d5.
     module.  Found by OSS Fuzz in #488466741(18).

   - gh-145492(19): Fix infinite recursion in *note
     collections.defaultdict: 1201. ‘__repr__’ when a ‘defaultdict’
     contains itself.  Based on analysis by KowalskiThomas in
     gh-145492(20).

   - gh-145623(21): Fix crash in *note struct: d5. when calling *note
     repr(): 803. or ‘__sizeof__()’ on an uninitialized *note
     struct.Struct: 15ad. object created via ‘Struct.__new__()’ without
     calling ‘__init__()’.

   - gh-145616(22): Detect Android sysconfig ABI correctly on 32-bit ARM
     Android on 64-bit ARM kernel

   - gh-145376(23): Fix null pointer dereference in unusual error
     scenario in *note hashlib: 68.

   - gh-145551(24): Fix InvalidStateError when cancelling process
     created by *note asyncio.create_subprocess_exec(): a86. or *note
     asyncio.create_subprocess_shell(): a87.  Patch by Daan De Meyer.

   - gh-145417(25): *note venv: 111.: Prevent incorrect preservation of
     SELinux context when copying the ‘Activate.ps1’ script.  The script
     inherited the SELinux security context of the system template
     directory, rather than the destination project directory.

   - gh-145301(26): *note hashlib: 68.: fix a crash when the
     initialization of the underlying C extension module fails.

   - gh-145264(27): Base64 decoder (see *note binascii.a2b_base64():
     15ae, *note base64.b64decode(): 15af, etc) no longer ignores excess
     data after the first padded quad in non-strict (default) mode.
     Instead, in conformance with RFC 4648(28), section 3.3, it now
     ignores the pad character, “=”, if it is present before the end of
     the encoded data.

   - gh-145158(29): Avoid undefined behaviour from signed integer
     overflow when parsing format strings in the *note struct: d5.
     module.

   - gh-144984(30): Fix crash in *note
     xml.parsers.expat.xmlparser.ExternalEntityParserCreate(): 15b0.
     when an allocation fails.  The error paths could dereference NULL
     ‘handlers’ and double-decrement the parent parser’s reference
     count.

   - gh-88091(31): Fix *note unicodedata.decomposition(): 15b1. for
     Hangul characters.

   - gh-144835(32): Added missing explanations for some parameters in
     *note glob.glob(): 29f. and *note glob.iglob(): 80d.

   - gh-144833(33): Fixed a use-after-free in *note ssl: d0. when
     ‘SSL_new()’ returns NULL in ‘newPySSLSocket()’.  The error was
     reported via a dangling pointer after the object had already been
     freed.

   - gh-144259(34): Fix inconsistent display of long multiline pasted
     content in the REPL.

   - gh-144156(35): Fix the folding of headers by the *note email: 3b.
     library when RFC 2047(36) encoded words are used.  Now whitespace
     is correctly preserved and also correctly added between adjacent
     encoded words.  The latter property was broken by the fix for
     gh-92081(37), which mostly fixed previous failures to preserve
     whitespace.

   - gh-66305(38): Fixed a hang on Windows in the *note tempfile: e0.
     module when trying to create a temporary file or subdirectory in a
     non-writable directory.

   - gh-140814(39): *note multiprocessing.freeze_support(): 15b2. no
     longer sets the default start method as a side effect, which
     previously caused a subsequent *note
     multiprocessing.set_start_method(): 2c7. call to raise *note
     RuntimeError: 195.

   - gh-144475(40): Calling *note repr(): 803. on *note
     functools.partial(): 417. is now safer when the partial object’s
     internal attributes are replaced while the string representation is
     being generated.

   - gh-144538(41): Bump the version of pip bundled in ensurepip to
     version 26.0.1

   - gh-144363(42): Update bundled libexpat(43) to 2.7.4

   - gh-143637(44): Fixed a crash in socket.sendmsg() that could occur
     if ancillary data is mutated re-entrantly during argument parsing.

   - gh-143880(45): Fix data race in *note functools.partial(): 417. in
     the *note free threading: 15b3. build.

   - gh-143543(46): Fix a crash in itertools.groupby that could occur
     when a user-defined *note __eq__(): b13. method re-enters the
     iterator during key comparison.

   - gh-140652(47): Fix a crash in ‘_interpchannels.list_all()’ after
     closing a channel.

   - gh-143698(48): Allow 'scheduler' and 'setpgroup' arguments to be
     explicitly *note None: 678. when calling *note os.posix_spawn():
     220. or *note os.posix_spawnp(): 15b4.  Patch by Bénédikt Tran.

   - gh-143698(49): Raise *note TypeError: 2c3. instead of *note
     SystemError: 578. when the 'scheduler' in *note os.posix_spawn():
     220. or *note os.posix_spawnp(): 15b4. is not a tuple.  Patch by
     Bénédikt Tran.

   - gh-143304(50): Fix *note ctypes.CDLL: 9f4. to honor the ‘handle’
     parameter on POSIX systems.

   - gh-142781(51): *note zoneinfo: 134.: fix a crash when instantiating
     *note ZoneInfo: 8e8. objects for which the internal class-level
     cache is inconsistent.

   - gh-142763(52): Fix a race condition between *note
     zoneinfo.ZoneInfo: 8e8. creation and *note
     zoneinfo.ZoneInfo.clear_cache(): 15b5. that could raise *note
     KeyError: 345.

   - gh-142787(53): Fix assertion failure in *note sqlite3: cf. blob
     subscript when slicing with indices that result in an empty slice.

   - gh-142352(54): Fix *note asyncio.StreamWriter.start_tls(): 607. to
     transfer buffered data from *note StreamReader: 15b6. to the SSL
     layer, preventing data loss when upgrading a connection to TLS
     mid-stream (e.g., when implementing PROXY protocol support).

   - gh-141707(55): Don’t change *note tarfile.TarInfo: 1256. type from
     ‘AREGTYPE’ to ‘DIRTYPE’ when parsing GNU long name or link headers.

   - gh-139933(56): Improve *note AttributeError: 34e. suggestions for
     classes with a custom *note __dir__(): 15b7. method returning a
     list of unsortable values.  Patch by Bénédikt Tran.

   - gh-138891(57): Fix ‘SyntaxError’ when ‘inspect.get_annotations(f,
     eval_str=True)’ is called on a function annotated with a PEP
     646(58) ‘star_expression’

   - gh-137335(59): Get rid of any possibility of a name conflict for
     named pipes in *note multiprocessing: 94. and *note asyncio: a. on
     Windows, no matter how small.

   - gh-80667(60): Support lookup for Tangut Ideographs in *note
     unicodedata: 105.

   - bpo-40243(61): Fix ‘unicodedata.ucd_3_2_0.numeric()’ for
     non-decimal values.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144503

   (2) https://github.com/python/cpython/issues/146613

   (3) https://github.com/python/cpython/issues/146080

   (4) https://github.com/python/cpython/issues/146090

   (5) https://sqlite.org/rescode.html#busy

   (6) https://github.com/python/cpython/issues/146090

   (7) https://github.com/python/cpython/issues/145633

   (8) https://github.com/python/cpython/issues/146310

   (9) https://github.com/python/cpython/issues/146083

   (10) https://libexpat.github.io/

   (11) https://github.com/python/cpython/issues/146076

   (12) https://github.com/python/cpython/issues/146054

   (13) https://issues.oss-fuzz.com/issues/493449985

   (14) https://github.com/python/cpython/issues/145883

   (15) https://issues.oss-fuzz.com/issues/492245058

   (16) https://issues.oss-fuzz.com/issues/492230068

   (17) https://github.com/python/cpython/issues/145750

   (18) https://issues.oss-fuzz.com/issues/488466741

   (19) https://github.com/python/cpython/issues/145492

   (20) https://github.com/python/cpython/issues/145492

   (21) https://github.com/python/cpython/issues/145623

   (22) https://github.com/python/cpython/issues/145616

   (23) https://github.com/python/cpython/issues/145376

   (24) https://github.com/python/cpython/issues/145551

   (25) https://github.com/python/cpython/issues/145417

   (26) https://github.com/python/cpython/issues/145301

   (27) https://github.com/python/cpython/issues/145264

   (28) https://datatracker.ietf.org/doc/html/rfc4648.html

   (29) https://github.com/python/cpython/issues/145158

   (30) https://github.com/python/cpython/issues/144984

   (31) https://github.com/python/cpython/issues/88091

   (32) https://github.com/python/cpython/issues/144835

   (33) https://github.com/python/cpython/issues/144833

   (34) https://github.com/python/cpython/issues/144259

   (35) https://github.com/python/cpython/issues/144156

   (36) https://datatracker.ietf.org/doc/html/rfc2047.html

   (37) https://github.com/python/cpython/issues/92081

   (38) https://github.com/python/cpython/issues/66305

   (39) https://github.com/python/cpython/issues/140814

   (40) https://github.com/python/cpython/issues/144475

   (41) https://github.com/python/cpython/issues/144538

   (42) https://github.com/python/cpython/issues/144363

   (43) https://libexpat.github.io/

   (44) https://github.com/python/cpython/issues/143637

   (45) https://github.com/python/cpython/issues/143880

   (46) https://github.com/python/cpython/issues/143543

   (47) https://github.com/python/cpython/issues/140652

   (48) https://github.com/python/cpython/issues/143698

   (49) https://github.com/python/cpython/issues/143698

   (50) https://github.com/python/cpython/issues/143304

   (51) https://github.com/python/cpython/issues/142781

   (52) https://github.com/python/cpython/issues/142763

   (53) https://github.com/python/cpython/issues/142787

   (54) https://github.com/python/cpython/issues/142352

   (55) https://github.com/python/cpython/issues/141707

   (56) https://github.com/python/cpython/issues/139933

   (57) https://github.com/python/cpython/issues/138891

   (58) https://peps.python.org/pep-0646/

   (59) https://github.com/python/cpython/issues/137335

   (60) https://github.com/python/cpython/issues/80667

   (61) https://bugs.python.org/issue?@action=redirect&bpo=40243


File: python.info,  Node: Documentation<2>,  Next: Core and Builtins,  Prev: Library,  Up: Python 3 13 13 final

1.23.1.6 Documentation
......................

   - gh-126676(1): Expand *note argparse: 6. documentation for
     ‘type=bool’ with a demonstration of the surprising behavior and
     pointers to common alternatives.

   - gh-145450(2): Document missing public *note wave.Wave_write: 2b7.
     getter methods.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126676

   (2) https://github.com/python/cpython/issues/145450


File: python.info,  Node: Core and Builtins,  Next: Build,  Prev: Documentation<2>,  Up: Python 3 13 13 final

1.23.1.7 Core and Builtins
..........................

   - gh-148157(1): Fix an unlikely crash when parsing an invalid type
     comments for function parameters.  Found by OSS Fuzz in
     #492782951(2).

   - gh-146615(3): Fix a crash in *note __get__(): 1537. for *note
     METH_METHOD: 97a. descriptors when an invalid (non-type) object is
     passed as the second argument.  Patch by Steven Sun.

   - gh-146128(4): Fix a bug which could cause constant values to be
     partially corrupted in AArch64 JIT code.  This issue is
     theoretical, and hasn’t actually been observed in unmodified Python
     interpreters.

   - gh-146250(5): Fixed a memory leak in *note SyntaxError: 18d. when
     re-initializing it.

   - gh-146245(6): Fixed reference leaks in *note socket: cc. when audit
     hooks raise exceptions in *note socket.getaddrinfo(): 15ba. and
     ‘socket.sendto()’.

   - gh-146227(7): Fix wrong type in ‘_Py_atomic_load_uint16’ in the C11
     atomics backend (‘pyatomic_std.h’), which used a 32-bit atomic load
     instead of 16-bit.  Found by Mohammed Zuhaib.

   - gh-146056(8): Fix *note repr(): 803. for lists containing ‘NULL’s.

   - gh-145990(9): ‘python --help-env’ sections are now sorted by
     environment variable name.

   - gh-145376(10): Fix GC tracking in ‘structseq.__replace__()’.

   - gh-142183(11): Avoid a pathological case where repeated calls at a
     specific stack depth could be significantly slower.

   - gh-145783(12): Fix an unlikely crash in the parser when certain
     errors were erroneously not propagated.  Found by OSS Fuzz in
     #491369109(13).

   - gh-145701(14): Fix *note SystemError: 578. when ‘__classdict__’ or
     ‘__conditional_annotations__’ is in a class-scope inlined
     comprehension.  Found by OSS Fuzz in #491105000(15).

   - gh-145335(16): Fix a crash in *note os.pathconf(): 113f. when
     called with ‘-1’ as the path argument.

   - gh-145234(17): Fixed a ‘SystemError’ in the parser when an encoding
     cookie (for example, UTF-7) decodes to carriage returns (‘\r’).
     Newlines are now normalized after decoding in the string tokenizer.

     Patch by Pablo Galindo.

   - gh-130555(18): Fix use-after-free in *note dict.clear(): 15bb. when
     the dictionary values are embedded in an object and a destructor
     causes re-entrant mutation of the dictionary.

   - gh-145008(19): Fix a bug when calling certain methods at the
     recursion limit which manifested as a corruption of Python’s
     operand stack.  Patch by Ken Jin.

   - gh-144872(20): Fix heap buffer overflow in the parser found by
     OSS-Fuzz.

   - gh-144766(21): Fix a crash in fork child process when perf support
     is enabled.

   - gh-144759(22): Fix undefined behavior in the lexer when ‘start’ and
     ‘multi_line_start’ pointers are ‘NULL’ in
     ‘_PyLexer_remember_fstring_buffers()’ and
     ‘_PyLexer_restore_fstring_buffers()’.  The ‘NULL’ pointer
     arithmetic (‘NULL - valid_pointer’) is now guarded with explicit
     ‘NULL’ checks.

   - gh-144601(23): Fix crash when importing a module whose ‘PyInit’
     function raises an exception from a subinterpreter.

   - gh-143636(24): Fix a crash when calling *note
     SimpleNamespace.__replace__(): 1d1. on non-namespace instances.
     Patch by Bénédikt Tran.

   - gh-143650(25): Fix race condition in *note importlib: 77. where a
     thread could receive a stale module reference when another thread’s
     import fails.

   - gh-140594(26): Fix an out of bounds read when a single NUL
     character is read from the standard input.  Patch by Shamil
     Abdulaev.

   - gh-91636(27): While performing garbage collection, clear weakrefs
     to unreachable objects that are created during running of
     finalizers.  If those weakrefs were are not cleared, they could
     reveal unreachable objects.

   - gh-130327(28): Fix erroneous clearing of an object’s *note
     __dict__: 55e. if overwritten at runtime.

   - gh-80667(29): Literals using the ‘\N{name}’ escape syntax can now
     construct CJK ideographs and Hangul syllables using
     case-insensitive names.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/148157

   (2) https://issues.oss-fuzz.com/issues/492782951

   (3) https://github.com/python/cpython/issues/146615

   (4) https://github.com/python/cpython/issues/146128

   (5) https://github.com/python/cpython/issues/146250

   (6) https://github.com/python/cpython/issues/146245

   (7) https://github.com/python/cpython/issues/146227

   (8) https://github.com/python/cpython/issues/146056

   (9) https://github.com/python/cpython/issues/145990

   (10) https://github.com/python/cpython/issues/145376

   (11) https://github.com/python/cpython/issues/142183

   (12) https://github.com/python/cpython/issues/145783

   (13) https://issues.oss-fuzz.com/issues/491369109

   (14) https://github.com/python/cpython/issues/145701

   (15) https://issues.oss-fuzz.com/issues/491105000

   (16) https://github.com/python/cpython/issues/145335

   (17) https://github.com/python/cpython/issues/145234

   (18) https://github.com/python/cpython/issues/130555

   (19) https://github.com/python/cpython/issues/145008

   (20) https://github.com/python/cpython/issues/144872

   (21) https://github.com/python/cpython/issues/144766

   (22) https://github.com/python/cpython/issues/144759

   (23) https://github.com/python/cpython/issues/144601

   (24) https://github.com/python/cpython/issues/143636

   (25) https://github.com/python/cpython/issues/143650

   (26) https://github.com/python/cpython/issues/140594

   (27) https://github.com/python/cpython/issues/91636

   (28) https://github.com/python/cpython/issues/130327

   (29) https://github.com/python/cpython/issues/80667


File: python.info,  Node: Build,  Prev: Core and Builtins,  Up: Python 3 13 13 final

1.23.1.8 Build
..............

   - gh-146541(1): The Android testbed can now be built for 32-bit ARM
     and x86 targets.

   - gh-146450(2): The Android build script was modified to improve
     parity with other platform build scripts.

   - gh-145801(3): When Python build is optimized with GCC using PGO,
     use ‘-fprofile-update=atomic’ option to use atomic operations when
     updating profile information.  This option reduces the risk of gcov
     Data Files (.gcda) corruption which can cause random GCC crashes.
     Patch by Victor Stinner.

   - gh-129259(4): Fix AIX build failures caused by incorrect struct
     alignment in ‘_Py_CODEUNIT’ and ‘_Py_BackoffCounter’ by adding
     AIX-specific ‘#pragma pack’ directives.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/146541

   (2) https://github.com/python/cpython/issues/146450

   (3) https://github.com/python/cpython/issues/145801

   (4) https://github.com/python/cpython/issues/129259


File: python.info,  Node: Python 3 13 12 final,  Next: Python 3 13 11 final,  Prev: Python 3 13 13 final,  Up: Changelog

1.23.2 Python 3.13.12 final
---------------------------

'Release date: 2026-02-03'

* Menu:

* Windows: Windows<2>.
* Tools/Demos::
* Tests: Tests<2>.
* Security: Security<2>.
* Library: Library<2>.
* IDLE: IDLE<3>.
* Documentation: Documentation<3>.
* Core and Builtins: Core and Builtins<2>.
* C API::
* Build: Build<2>.


File: python.info,  Node: Windows<2>,  Next: Tools/Demos,  Up: Python 3 13 12 final

1.23.2.1 Windows
................

   - gh-128067(1): Fix a bug in PyREPL on Windows where output without a
     trailing newline was overwritten by the next prompt.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/128067


File: python.info,  Node: Tools/Demos,  Next: Tests<2>,  Prev: Windows<2>,  Up: Python 3 13 12 final

1.23.2.2 Tools/Demos
....................

   - gh-142095(1): Make gdb ‘py-bt’ command use frame from thread local
     state when available.  Patch by Sam Gross and Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142095


File: python.info,  Node: Tests<2>,  Next: Security<2>,  Prev: Tools/Demos,  Up: Python 3 13 12 final

1.23.2.3 Tests
..............

   - gh-144415(1): The Android testbed now distinguishes between
     stdout/stderr messages which were triggered by a newline, and those
     triggered by a manual call to ‘flush’.  This fixes logging of
     progress indicators and similar content.

   - gh-65784(2): Add support for parametrized resource ‘wantobjects’ in
     regrtests, which allows to run Tkinter tests with the specified
     value of ‘tkinter.wantobjects’, for example ‘-u wantobjects=0’.

   - gh-143553(3): Add support for parametrized resources, such as ‘-u
     xpickle=2.7’.

   - gh-142836(4): Accommodated Solaris in
     ‘test_pdb.test_script_target_anonymous_pipe’.

   - gh-129401(5): Fix a flaky test in ‘test_repr_rlock’ that checks the
     representation of *note multiprocessing.RLock: 15c1.

   - bpo-31391(6): Forward-port test_xpickle from Python 2 to Python 3
     and add the resource back to test’s command line.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144415

   (2) https://github.com/python/cpython/issues/65784

   (3) https://github.com/python/cpython/issues/143553

   (4) https://github.com/python/cpython/issues/142836

   (5) https://github.com/python/cpython/issues/129401

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31391


File: python.info,  Node: Security<2>,  Next: Library<2>,  Prev: Tests<2>,  Up: Python 3 13 12 final

1.23.2.4 Security
.................

   - gh-144125(1): *note BytesGenerator: 1214. will now refuse to
     serialize (write) headers that are unsafely folded or delimited;
     see *note verify_generated_headers: 1e0.  (Contributed by Bas
     Bloemsaat and Petr Viktorin in gh-121650(2)).

   - gh-143935(3): Fixed a bug in the folding of comments when
     flattening an email message using a modern email policy.  Comments
     consisting of a very long sequence of non-foldable characters could
     trigger a forced line wrap that omitted the required leading space
     on the continuation line, causing the remainder of the comment to
     be interpreted as a new header field.  This enabled header
     injection with carefully crafted inputs.

   - gh-143925(4): Reject control characters in ‘data:’ URL media types.

   - gh-143919(5): Reject control characters in *note
     http.cookies.Morsel: c24. fields and values.

   - gh-143916(6): Reject C0 control characters within
     wsgiref.headers.Headers fields, values, and parameters.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144125

   (2) https://github.com/python/cpython/issues/121650

   (3) https://github.com/python/cpython/issues/143935

   (4) https://github.com/python/cpython/issues/143925

   (5) https://github.com/python/cpython/issues/143919

   (6) https://github.com/python/cpython/issues/143916


File: python.info,  Node: Library<2>,  Next: IDLE<3>,  Prev: Security<2>,  Up: Python 3 13 12 final

1.23.2.5 Library
................

   - gh-144380(1): Improve performance of *note io.BufferedReader: 1253.
     line iteration by ~49%.

   - gh-144169(2): Fix three crashes when non-string keyword arguments
     are supplied to objects in the *note ast: 8. module.

   - gh-144100(3): Fixed a crash in ctypes when using a deprecated
     ‘POINTER(str)’ type in ‘argtypes’.  Instead of aborting, ctypes now
     raises a proper Python exception when the pointer target type is
     unresolved.

   - gh-144050(4): Fix *note stat.filemode(): 118f. in the pure-Python
     implementation to avoid misclassifying invalid mode values as block
     devices.

   - gh-144023(5): Fixed validation of file descriptor 0 in posix
     functions when used with follow_symlinks parameter.

   - gh-143999(6): Fix an issue where *note inspect.getgeneratorstate():
     127c. and *note inspect.getcoroutinestate(): e4b. could fail for
     generators wrapped by *note types.coroutine(): ebc. in the
     suspended state.

   - gh-143706(7): Fix *note multiprocessing: 94. forkserver so that
     *note sys.argv: 12ab. is correctly set before ‘__main__’ is
     preloaded.  Previously, ‘sys.argv’ was empty during main module
     import in forkserver child processes.  This fixes a regression
     introduced in 3.13.8 and 3.14.1.  Root caused by Aaron Wieczorek,
     test provided by Thomas Watson, thanks!

   - gh-143638(8): Forbid reentrant calls of the *note pickle.Pickler:
     a2b. and *note pickle.Unpickler: 15c4. methods for the C
     implementation.  Previously, this could cause crash or data
     corruption, now concurrent calls of methods of the same object
     raise *note RuntimeError: 195.

   - gh-78724(9): Raise *note RuntimeError: 195.’s when user attempts to
     call methods on half-initialized *note Struct: 15ad. objects, For
     example, created by ‘Struct.__new__(Struct)’.  Patch by Sergey B
     Kirpichev.

   - gh-143602(10): Fix a inconsistency issue in *note write(): 13f8.
     that leads to unexpected buffer overwrite by deduplicating the
     buffer exports.

   - gh-143547(11): Fix *note sys.unraisablehook(): 1f7. when the hook
     raises an exception and changes ‘sys.unraisablehook()’: hold a
     strong reference to the old hook.  Patch by Victor Stinner.

   - gh-143378(12): Fix use-after-free crashes when a *note BytesIO:
     ed8. object is concurrently mutated during *note write(): 13f8. or
     *note writelines(): 15c5.

   - gh-143346(13): Fix incorrect wrapping of the Base64 data in
     ‘plistlib._PlistWriter’ when the indent contains a mix of tabs and
     spaces.

   - gh-143310(14): *note tkinter: f0.: fix a crash when a Python *note
     list: 614. is mutated during the conversion to a Tcl object (e.g.,
     when setting a Tcl variable).  Patch by Bénédikt Tran.

   - gh-143309(15): Fix a crash in *note os.execve(): 113d. on
     non-Windows platforms when given a custom environment mapping which
     is then mutated during parsing.  Patch by Bénédikt Tran.

   - gh-143308(16): *note pickle: a6.: fix use-after-free crashes when a
     *note PickleBuffer: 15c6. is concurrently mutated by a custom
     buffer callback during pickling.  Patch by Bénédikt Tran and Aaron
     Wieczorek.

   - gh-143237(17): Fix support of named pipes in the rotating *note
     logging: 87. handlers.

   - gh-143249(18): Fix possible buffer leaks in Windows overlapped I/O
     on error handling.

   - gh-143241(19): *note zoneinfo: 134.: fix infinite loop in *note
     ZoneInfo.from_file: 15c7. when parsing a malformed TZif file.
     Patch by Fatih Celik.

   - gh-142830(20): *note sqlite3: cf.: fix use-after-free crashes when
     the connection’s callbacks are mutated during a callback execution.
     Patch by Bénédikt Tran.

   - gh-143200(21): *note xml.etree.ElementTree: 125.: fix
     use-after-free crashes in *note __getitem__(): 283. and *note
     __setitem__(): 1313. methods of *note Element: 310. when the
     element is concurrently mutated.  Patch by Bénédikt Tran.

   - gh-142195(22): Updated timeout evaluation logic in *note
     subprocess: d6. to be compatible with deterministic environments
     like Shadow where time moves exactly as requested.

   - gh-143145(23): Fixed a possible reference leak in ctypes when
     constructing results with multiple output parameters on error.

   - gh-122431(24): Corrected the error message in *note
     readline.append_history_file(): e85. to state that ‘nelements’ must
     be non-negative instead of positive.

   - gh-143004(25): Fix a potential use-after-free in *note
     collections.Counter.update(): 15c8. when user code mutates the
     Counter during an update.

   - gh-143046(26): The *note asyncio: a. REPL no longer prints
     copyright and version messages in the quiet mode (*note -q: 15c9.).
     Patch by Bartosz Sławecki.

   - gh-140648(27): The *note asyncio: a. REPL now respects the *note
     -I: 968. flag (isolated mode).  Previously, it would load and
     execute *note PYTHONSTARTUP: 1003. even if the flag was set.
     Contributed by Bartosz Sławecki.

   - gh-142991(28): Fixed socket operations such as recvfrom() and
     sendto() for FreeBSD divert(4) socket.

   - gh-143010(29): Fixed a bug in *note mailbox: 8b. where the precise
     timing of an external event could result in the library opening an
     existing file instead of a file it expected to create.

   - gh-142881(30): Fix concurrent and reentrant call of *note
     atexit.unregister(): 15ca.

   - gh-112127(31): Fix possible use-after-free in *note
     atexit.unregister(): 15ca. when the callback is unregistered during
     comparison.

   - gh-142783(32): Fix zoneinfo use-after-free with descriptor
     _weak_cache.  a descriptor as _weak_cache could cause crashes
     during object creation.  The fix ensures proper reference counting
     for descriptor-provided objects.

   - gh-142754(33): Add the 'ownerDocument' attribute to *note
     xml.dom.minidom: 122. elements and attributes created by directly
     instantiating the ‘Element’ or ‘Attr’ class.  Note that this way of
     creating nodes is not supported; creator functions like *note
     xml.dom.Document.documentElement(): 15cb. should be used instead.

   - gh-142784(34): The *note asyncio: a. REPL now properly closes the
     loop upon the end of interactive session.  Previously, it could
     cause surprising warnings.  Contributed by Bartosz Sławecki.

   - gh-142555(35): *note array: 7.: fix a crash in ‘a[i] = v’ when
     converting 'i' to an index via *note i.__index__: 720. or *note
     i.__float__: 9d7. mutates the array.

   - gh-142594(36): Fix crash in ‘TextIOWrapper.close()’ when the
     underlying buffer’s ‘closed’ property calls *note detach(): 15cc.

   - gh-142451(37): *note hmac: 6a.: Ensure that the *note
     HMAC.block_size: f83. attribute is correctly copied by *note
     HMAC.copy: 15cd.  Patch by Bénédikt Tran.

   - gh-142495(38): *note collections.defaultdict: 1201. now prioritizes
     *note __setitem__(): 1313. when inserting default values from
     ‘default_factory’.  This prevents race conditions where a default
     value would overwrite a value set before ‘default_factory’ returns.

   - gh-142651(39): *note unittest.mock: 107.: fix a thread safety issue
     where *note Mock.call_count: 15ce. may return inaccurate values
     when the mock is called concurrently from multiple threads.

   - gh-142595(40): Added type check during initialization of the *note
     decimal: 36. module to prevent a crash in case of broken stdlib.
     Patch by Sergey B Kirpichev.

   - gh-142517(41): The non-‘compat32’ *note email: 3b. policies now
     correctly handle refolding encoded words that contain bytes that
     can not be decoded in their specified character set.  Previously
     this resulted in an encoding exception during folding.

   - gh-112527(42): The help text for required options in *note
     argparse: 6. no longer extended with “ (default: None)”.

   - gh-142315(43): Pdb can now run scripts from anonymous pipes used in
     process substitution.  Patch by Bartosz Sławecki.

   - gh-142282(44): Fix *note winreg.QueryValueEx(): 15cf. to not
     accidentally read garbage buffer under race condition.

   - gh-75949(45): Fix *note argparse: 6. to preserve ‘|’ separators in
     mutually exclusive groups when the usage line wraps due to length.

   - gh-68552(46): ‘MisplacedEnvelopeHeaderDefect’ and ‘Missing header
     name’ defects are now correctly passed to the ‘handle_defect’
     method of ‘policy’ in *note FeedParser: 15d0.

   - gh-142006(47): Fix a bug in the *note email.policy.default: 15d1.
     folding algorithm which incorrectly resulted in a doubled newline
     when a line ending at exactly max_line_length was followed by an
     unfoldable token.

   - gh-105836(48): Fix *note asyncio.run_coroutine_threadsafe(): 889.
     leaving underlying cancelled asyncio task running.

   - gh-139971(49): *note pydoc: b5.: Ensure that the link to the online
     documentation of a *note stdlib: 15d2. module is correct.

   - gh-139262(50): Some keystrokes can be swallowed in the new ‘PyREPL’
     on Windows, especially when used together with the ALT key.  Fix by
     Chris Eibl.

   - gh-138897(51): Improved *note license: 15d3./*note copyright:
     15d4./*note credits: 15d5. display in the *note REPL: 16a.: now
     uses a pager.

   - gh-79986(52): Add parsing for ‘References’ and ‘In-Reply-To’
     headers to the *note email: 3b. library that parses the header
     content as lists of message id tokens.  This prevents them from
     being folded incorrectly.

   - gh-109263(53): Starting a process from spawn context in *note
     multiprocessing: 94. no longer sets the start method globally.

   - gh-90871(54): Fixed an off by one error concerning the backlog
     parameter in *note create_unix_server(): 1ae.  Contributed by
     Christian Harries.

   - gh-133253(55): Fix thread-safety issues in *note linecache: 85.

   - gh-132715(56): Skip writing objects during marshalling once a
     failure has occurred.

   - gh-127529(57): Correct behavior of
     ‘asyncio.selector_events.BaseSelectorEventLoop._accept_connection()’
     in handling *note ConnectionAbortedError: 109b. in a loop.  This
     improves performance on OpenBSD.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144380

   (2) https://github.com/python/cpython/issues/144169

   (3) https://github.com/python/cpython/issues/144100

   (4) https://github.com/python/cpython/issues/144050

   (5) https://github.com/python/cpython/issues/144023

   (6) https://github.com/python/cpython/issues/143999

   (7) https://github.com/python/cpython/issues/143706

   (8) https://github.com/python/cpython/issues/143638

   (9) https://github.com/python/cpython/issues/78724

   (10) https://github.com/python/cpython/issues/143602

   (11) https://github.com/python/cpython/issues/143547

   (12) https://github.com/python/cpython/issues/143378

   (13) https://github.com/python/cpython/issues/143346

   (14) https://github.com/python/cpython/issues/143310

   (15) https://github.com/python/cpython/issues/143309

   (16) https://github.com/python/cpython/issues/143308

   (17) https://github.com/python/cpython/issues/143237

   (18) https://github.com/python/cpython/issues/143249

   (19) https://github.com/python/cpython/issues/143241

   (20) https://github.com/python/cpython/issues/142830

   (21) https://github.com/python/cpython/issues/143200

   (22) https://github.com/python/cpython/issues/142195

   (23) https://github.com/python/cpython/issues/143145

   (24) https://github.com/python/cpython/issues/122431

   (25) https://github.com/python/cpython/issues/143004

   (26) https://github.com/python/cpython/issues/143046

   (27) https://github.com/python/cpython/issues/140648

   (28) https://github.com/python/cpython/issues/142991

   (29) https://github.com/python/cpython/issues/143010

   (30) https://github.com/python/cpython/issues/142881

   (31) https://github.com/python/cpython/issues/112127

   (32) https://github.com/python/cpython/issues/142783

   (33) https://github.com/python/cpython/issues/142754

   (34) https://github.com/python/cpython/issues/142784

   (35) https://github.com/python/cpython/issues/142555

   (36) https://github.com/python/cpython/issues/142594

   (37) https://github.com/python/cpython/issues/142451

   (38) https://github.com/python/cpython/issues/142495

   (39) https://github.com/python/cpython/issues/142651

   (40) https://github.com/python/cpython/issues/142595

   (41) https://github.com/python/cpython/issues/142517

   (42) https://github.com/python/cpython/issues/112527

   (43) https://github.com/python/cpython/issues/142315

   (44) https://github.com/python/cpython/issues/142282

   (45) https://github.com/python/cpython/issues/75949

   (46) https://github.com/python/cpython/issues/68552

   (47) https://github.com/python/cpython/issues/142006

   (48) https://github.com/python/cpython/issues/105836

   (49) https://github.com/python/cpython/issues/139971

   (50) https://github.com/python/cpython/issues/139262

   (51) https://github.com/python/cpython/issues/138897

   (52) https://github.com/python/cpython/issues/79986

   (53) https://github.com/python/cpython/issues/109263

   (54) https://github.com/python/cpython/issues/90871

   (55) https://github.com/python/cpython/issues/133253

   (56) https://github.com/python/cpython/issues/132715

   (57) https://github.com/python/cpython/issues/127529


File: python.info,  Node: IDLE<3>,  Next: Documentation<3>,  Prev: Library<2>,  Up: Python 3 13 12 final

1.23.2.6 IDLE
.............

   - gh-143774(1): Better explain the operation of Format / Format
     Paragraph.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/143774


File: python.info,  Node: Documentation<3>,  Next: Core and Builtins<2>,  Prev: IDLE<3>,  Up: Python 3 13 12 final

1.23.2.7 Documentation
......................

   - gh-140806(1): Add documentation for *note enum.bin(): 15d8.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/140806


File: python.info,  Node: Core and Builtins<2>,  Next: C API,  Prev: Documentation<3>,  Up: Python 3 13 12 final

1.23.2.8 Core and Builtins
..........................

   - gh-144307(1): Prevent a reference leak in module teardown at
     interpreter finalization.

   - gh-144194(2): Fix error handling in perf jitdump initialization on
     memory allocation failure.

   - gh-141805(3): Fix crash in *note set: 5dc. when objects with the
     same hash are concurrently added to the set after removing an
     element with the same hash while the set still contains elements
     with the same hash.

   - gh-143670(4): Fixes a crash in ‘ga_repr_items_list’ function.

   - gh-143377(5): Fix a crash in ‘_interpreters.capture_exception()’
     when the exception is incorrectly formatted.  Patch by Bénédikt
     Tran.

   - gh-143189(6): Fix crash when inserting a non-*note str: 44f. key
     into a split table dictionary when the key matches an existing key
     in the split table but has no corresponding value in the dict.

   - gh-143228(7): Fix use-after-free in perf trampoline when toggling
     profiling while threads are running or during interpreter
     finalization with daemon threads active.  The fix uses reference
     counting to ensure trampolines are not freed while any code object
     could still reference them.  Pach by Pablo Galindo

   - gh-142664(8): Fix a use-after-free crash in *note
     memoryview.__hash__: b14. when the ‘__hash__’ method of the
     referenced object mutates that object or the view.  Patch by
     Bénédikt Tran.

   - gh-142557(9): Fix a use-after-free crash in *note
     bytearray.__mod__: daf. when the ‘bytearray’ is mutated while
     formatting the ‘%’-style arguments.  Patch by Bénédikt Tran.

   - gh-143195(10): Fix use-after-free crashes in *note bytearray.hex():
     d94. and *note memoryview.hex(): d95. when the separator’s *note
     __len__(): 15da. mutates the original object.  Patch by Bénédikt
     Tran.

   - gh-143135(11): Set *note sys.flags.inspect: 15db. to ‘1’ when *note
     PYTHONINSPECT: 1529. is ‘0’.  Previously, it was set to ‘0’ in this
     case.

   - gh-143003(12): Fix an overflow of the shared empty buffer in *note
     bytearray.extend(): 15dc. when ‘__length_hint__()’ returns 0 for
     non-empty iterator.

   - gh-143006(13): Fix a possible assertion error when comparing
     negative non-integer ‘float’ and ‘int’ with the same number of bits
     in the integer part.

   - gh-142776(14): Fix a file descriptor leak in import.c

   - gh-142829(15): Fix a use-after-free crash in *note
     contextvars.Context: 15dd. comparison when a custom ‘__eq__’ method
     modifies the context via *note set(): 15de.

   - gh-142766(16): Clear the frame of a generator when *note
     generator.close(): 15df. is called.

   - gh-142737(17): Tracebacks will be displayed in fallback mode even
     if *note io.open(): 520. is lost.  Previously, this would crash the
     interpreter.  Patch by Bartosz Sławecki.

   - gh-142554(18): Fix a crash in *note divmod(): 9ac. when
     ‘_pylong.int_divmod()’ does not return a tuple of length two
     exactly.  Patch by Bénédikt Tran.

   - gh-142560(19): Fix use-after-free in *note bytearray: 2ea.
     search-like methods (*note find(): 13f0, *note count(): 15e0, *note
     index(): 15e1, *note rindex(): 15e2, and *note rfind(): 13f1.) by
     marking the storage as exported which causes reallocation attempts
     to raise *note BufferError: 15e3.  For *note contains(): 8e3, *note
     split(): 15e4, and *note rsplit(): 15e5. the *note buffer protocol:
     2e8. is used for this.

   - gh-142343(20): Fix SIGILL crash on m68k due to incorrect assembly
     constraint.

   - gh-141732(21): Ensure the *note __repr__(): 61f. for *note
     ExceptionGroup: 1b6. and *note BaseExceptionGroup: 25f. does not
     change when the exception sequence that was original passed in to
     its constructor is subsequently mutated.

   - gh-100964(22): Fix reference cycle in exhausted generator frames.
     Patch by Savannah Ostrowski.

   - gh-140373(23): Correctly emit ‘PY_UNWIND’ event when generator
     object is closed.  Patch by Mikhail Efimov.

   - gh-138568(24): Adjusted the built-in *note help(): 8e0. function so
     that empty inputs are ignored in interactive mode.

   - gh-127773(25): Do not use the type attribute cache for types with
     incompatible *note MRO: 15e6.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/144307

   (2) https://github.com/python/cpython/issues/144194

   (3) https://github.com/python/cpython/issues/141805

   (4) https://github.com/python/cpython/issues/143670

   (5) https://github.com/python/cpython/issues/143377

   (6) https://github.com/python/cpython/issues/143189

   (7) https://github.com/python/cpython/issues/143228

   (8) https://github.com/python/cpython/issues/142664

   (9) https://github.com/python/cpython/issues/142557

   (10) https://github.com/python/cpython/issues/143195

   (11) https://github.com/python/cpython/issues/143135

   (12) https://github.com/python/cpython/issues/143003

   (13) https://github.com/python/cpython/issues/143006

   (14) https://github.com/python/cpython/issues/142776

   (15) https://github.com/python/cpython/issues/142829

   (16) https://github.com/python/cpython/issues/142766

   (17) https://github.com/python/cpython/issues/142737

   (18) https://github.com/python/cpython/issues/142554

   (19) https://github.com/python/cpython/issues/142560

   (20) https://github.com/python/cpython/issues/142343

   (21) https://github.com/python/cpython/issues/141732

   (22) https://github.com/python/cpython/issues/100964

   (23) https://github.com/python/cpython/issues/140373

   (24) https://github.com/python/cpython/issues/138568

   (25) https://github.com/python/cpython/issues/127773


File: python.info,  Node: C API,  Next: Build<2>,  Prev: Core and Builtins<2>,  Up: Python 3 13 12 final

1.23.2.9 C API
..............

   - gh-142571(1): ‘PyUnstable_CopyPerfMapFile()’ now checks that
     opening the file succeeded before flushing.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142571


File: python.info,  Node: Build<2>,  Prev: C API,  Up: Python 3 13 12 final

1.23.2.10 Build
...............

   - gh-142454(1): When calculating the digest of the JIT stencils
     input, sort the hashed files by filenames before adding their
     content to the hasher.  This ensures deterministic hash input and
     hence deterministic hash, independent on filesystem order.

   - gh-141808(2): When running ‘make clean-retain-profile’, keep the
     generated JIT stencils.  That way, the stencils are not generated
     twice when Profile-guided optimization (PGO) is used.  It also
     allows distributors to supply their own pre-built JIT stencils.

   - gh-138061(3): Ensure reproducible builds by making JIT stencil
     header generation deterministic.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142454

   (2) https://github.com/python/cpython/issues/141808

   (3) https://github.com/python/cpython/issues/138061


File: python.info,  Node: Python 3 13 11 final,  Next: Python 3 13 10 final,  Prev: Python 3 13 12 final,  Up: Changelog

1.23.3 Python 3.13.11 final
---------------------------

'Release date: 2025-12-05'

* Menu:

* Security: Security<3>.
* Library: Library<3>.
* Core and Builtins: Core and Builtins<3>.


File: python.info,  Node: Security<3>,  Next: Library<3>,  Up: Python 3 13 11 final

1.23.3.1 Security
.................

   - gh-142145(1): Remove quadratic behavior in ‘xml.minidom’ node ID
     cache clearing.

   - gh-119451(2): Fix a potential memory denial of service in the *note
     http.client: 6f. module.  When connecting to a malicious server, it
     could cause an arbitrary amount of memory to be allocated.  This
     could have led to symptoms including a *note MemoryError: 15ab,
     swapping, out of memory (OOM) killed processes or containers, or
     even system crashes.

   - gh-119452(3): Fix a potential memory denial of service in the *note
     http.server: 72. module.  When a malicious user is connected to the
     CGI server on Windows, it could cause an arbitrary amount of memory
     to be allocated.  This could have led to symptoms including a *note
     MemoryError: 15ab, swapping, out of memory (OOM) killed processes
     or containers, or even system crashes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142145

   (2) https://github.com/python/cpython/issues/119451

   (3) https://github.com/python/cpython/issues/119452


File: python.info,  Node: Library<3>,  Next: Core and Builtins<3>,  Prev: Security<3>,  Up: Python 3 13 11 final

1.23.3.2 Library
................

   - gh-140797(1): Revert changes to the undocumented ‘re.Scanner’
     class.  Capturing groups are still allowed for backward
     compatibility, although using them can lead to incorrect result.
     They will be forbidden in future Python versions.

   - gh-142206(2): The resource tracker in the *note multiprocessing:
     94. module now uses the original communication protocol, as in
     Python 3.14.0 and below, by default.  This avoids issues with
     upgrading Python while it is running.  (Note that such ‘in-place’
     upgrades are not tested.)  The tracker remains compatible with
     subprocesses that use new protocol (that is, subprocesses using
     Python 3.13.10, 3.14.1 and 3.15).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/140797

   (2) https://github.com/python/cpython/issues/142206


File: python.info,  Node: Core and Builtins<3>,  Prev: Library<3>,  Up: Python 3 13 11 final

1.23.3.3 Core and Builtins
..........................

   - gh-142218(1): Fix crash when inserting into a split table
     dictionary with a non *note str: 44f. key that matches an existing
     key.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142218


File: python.info,  Node: Python 3 13 10 final,  Next: Python 3 13 9 final,  Prev: Python 3 13 11 final,  Up: Changelog

1.23.4 Python 3.13.10 final
---------------------------

'Release date: 2025-12-02'

* Menu:

* Tools/Demos: Tools/Demos<2>.
* Tests: Tests<3>.
* Security: Security<4>.
* Library: Library<4>.
* IDLE: IDLE<4>.
* Documentation: Documentation<4>.
* Core and Builtins: Core and Builtins<4>.
* C API: C API<2>.


File: python.info,  Node: Tools/Demos<2>,  Next: Tests<3>,  Up: Python 3 13 10 final

1.23.4.1 Tools/Demos
....................

   - gh-141442(1): The iOS testbed now correctly handles test arguments
     that contain spaces.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/141442


File: python.info,  Node: Tests<3>,  Next: Security<4>,  Prev: Tools/Demos<2>,  Up: Python 3 13 10 final

1.23.4.2 Tests
..............

   - gh-140482(1): Preserve and restore the state of ‘stty echo’ as part
     of the test environment.

   - gh-140082(2): Update ‘python -m test’ to set ‘FORCE_COLOR=1’ when
     being run with color enabled so that *note unittest: 106. which is
     run by it with redirected output will output in color.

   - gh-136442(3): Use exitcode ‘1’ instead of ‘5’ if *note
     unittest.TestCase.setUpClass(): a5c. raises an exception

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/140482

   (2) https://github.com/python/cpython/issues/140082

   (3) https://github.com/python/cpython/issues/136442


File: python.info,  Node: Security<4>,  Next: Library<4>,  Prev: Tests<3>,  Up: Python 3 13 10 final

1.23.4.3 Security
.................

   - gh-139700(1): Check consistency of the zip64 end of central
     directory record.  Support records with “zip64 extensible data” if
     there are no bytes prepended to the ZIP file.

   - gh-137836(2): Add support of the “plaintext” element, RAWTEXT
     elements “xmp”, “iframe”, “noembed” and “noframes”, and optionally
     RAWTEXT element “noscript” in *note html.parser.HTMLParser: 87e.

   - gh-136063(3): *note email.message: 44.: ensure linear complexity
     for legacy HTTP parameters parsing.  Patch by Bénédikt Tran.

   - gh-136065(4): Fix quadratic complexity in *note
     os.path.expandvars(): 1427.

   - gh-119342(5): Fix a potential memory denial of service in the *note
     plistlib: ab. module.  When reading a Plist file received from
     untrusted source, it could cause an arbitrary amount of memory to
     be allocated.  This could have led to symptoms including a *note
     MemoryError: 15ab, swapping, out of memory (OOM) killed processes
     or containers, or even system crashes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139700

   (2) https://github.com/python/cpython/issues/137836

   (3) https://github.com/python/cpython/issues/136063

   (4) https://github.com/python/cpython/issues/136065

   (5) https://github.com/python/cpython/issues/119342


File: python.info,  Node: Library<4>,  Next: IDLE<4>,  Prev: Security<4>,  Up: Python 3 13 10 final

1.23.4.4 Library
................

   - gh-74389(1): When the stdin being used by a *note subprocess.Popen:
     199. instance is closed, this is now ignored in *note
     subprocess.Popen.communicate(): 15f2. instead of leaving the class
     in an inconsistent state.

   - gh-87512(2): Fix *note subprocess.Popen.communicate(): 15f2.
     timeout handling on Windows when writing large input.  Previously,
     the timeout was ignored during stdin writing, causing the method to
     block indefinitely if the child process did not consume input
     quickly.  The stdin write is now performed in a background thread,
     allowing the timeout to be properly enforced.

   - gh-141473(3): When *note subprocess.Popen.communicate(): 15f2. was
     called with 'input' and a 'timeout' and is called for a second time
     after a *note TimeoutExpired: 15f3. exception before the process
     has died, it should no longer hang.

   - gh-59000(4): Fix *note pdb: a5. breakpoint resolution for class
     methods when the module defining the class is not imported.

   - gh-141570(5): Support *note file-like object: 15f4. raising *note
     OSError: 41a. from *note fileno(): 15f5. in color detection
     (‘_colorize.can_colorize()’).  This can occur when ‘sys.stdout’ is
     redirected.

   - gh-141659(6): Fix bad file descriptor errors from
     ‘_posixsubprocess’ on AIX.

   - gh-141497(7): *note ipaddress: 80.: ensure that the methods *note
     IPv4Network.hosts(): 15f6. and *note IPv6Network.hosts(): 15f7.
     always return an iterator.

   - gh-140938(8): The *note statistics.stdev(): 6d7. and *note
     statistics.pstdev(): 15f8. functions now raise a *note ValueError:
     202. when the input contains an infinity or a NaN.

   - gh-124111(9): Updated Tcl threading configuration in *note
     _tkinter: 3. to assume that threads are always available in Tcl 9
     and later.

   - gh-137109(10): The *note os.fork: 197. and related forking APIs
     will no longer warn in the common case where Linux or macOS
     platform APIs return the number of threads in a process and find
     the answer to be 1 even when a *note os.register_at_fork(): 300.
     ‘after_in_parent=’ callback (re)starts a thread.

   - gh-141314(11): Fix assertion failure in *note
     io.TextIOWrapper.tell(): 15f9. when reading files with standalone
     carriage return (‘\r’) line endings.

   - gh-141311(12): Fix assertion failure in ‘io.BytesIO.readinto()’ and
     undefined behavior arising when read position is above capcity in
     *note io.BytesIO: ed8.

   - gh-141141(13): Fix a thread safety issue with *note
     base64.b85decode(): f58.  Contributed by Benel Tayar.

   - gh-140911(14): *note collections: 1d.: Ensure that the methods
     ‘UserString.rindex()’ and ‘UserString.index()’ accept *note
     collections.UserString: e03. instances as the sub argument.

   - gh-140797(15): The undocumented ‘re.Scanner’ class now forbids
     regular expressions containing capturing groups in its lexicon
     patterns.  Patterns using capturing groups could previously lead to
     crashes with segmentation fault.  Use non-capturing groups (?:…)
     instead.

   - gh-140815(16): *note faulthandler: 58. now detects if a frame or a
     code object is invalid or freed.  Patch by Victor Stinner.

   - gh-100218(17): Correctly set *note errno: 15fa. when *note
     socket.if_nametoindex(): a3b. or *note socket.if_indextoname():
     a3c. raise an *note OSError: 41a.  Patch by Bénédikt Tran.

   - gh-140875(18): Fix handling of unclosed character references (named
     and numerical) followed by the end of file in *note
     html.parser.HTMLParser: 87e. with ‘convert_charrefs=False’.

   - gh-140734(19): *note multiprocessing: 94.: fix off-by-one error
     when checking the length of a temporary socket file path.  Patch by
     Bénédikt Tran.

   - gh-140874(20): Bump the version of pip bundled in *note ensurepip:
     55. to version 25.3

   - gh-140691(21): In *note urllib.request: 10b, when opening a FTP URL
     fails because a data connection cannot be made, the control
     connection’s socket is now closed to avoid a *note ResourceWarning:
     244.

   - gh-103847(22): Fix hang when cancelling process created by *note
     asyncio.create_subprocess_exec(): a86. or *note
     asyncio.create_subprocess_shell(): a87.  Patch by Kumar Aditya.

   - gh-140590(23): Fix arguments checking for the
     ‘functools.partial.__setstate__()’ that may lead to internal state
     corruption and crash.  Patch by Sergey Miryanov.

   - gh-140634(24): Fix a reference counting bug in
     ‘os.sched_param.__reduce__()’.

   - gh-140633(25): Ignore *note AttributeError: 34e. when setting a
     module’s ‘__file__’ attribute when loading an extension module
     packaged as Apple Framework.

   - gh-140593(26): *note xml.parsers.expat: 126.: Fix a memory leak
     that could affect users with *note ElementDeclHandler(): 15a5. set
     to a custom element declaration handler.  Patch by Sebastian
     Pipping.

   - gh-140607(27): Inside *note io.RawIOBase.read(): e4e, validate that
     the count of bytes returned by *note io.RawIOBase.readinto(): e4f.
     is valid (inside the provided buffer).

   - gh-138162(28): Fix *note logging.LoggerAdapter: 133e. with
     ‘merge_extra=True’ and without the 'extra' argument.

   - gh-140474(29): Fix memory leak in *note array.array: 1a0. when
     creating arrays from an empty *note str: 44f. and the ‘u’ type
     code.

   - gh-140272(30): Fix memory leak in the ‘clear()’ method of the *note
     dbm.gnu: 33. database.

   - gh-140041(31): Fix import of *note ctypes: 2a. on Android and
     Cygwin when ABI flags are present.

   - gh-139905(32): Add suggestion to error message for *note
     typing.Generic: 15fb. subclasses when ‘cls.__parameters__’ is
     missing due to a parent class failing to call *note
     super().__init_subclass__(): 634. in its ‘__init_subclass__’.

   - gh-139845(33): Fix to not print KeyboardInterrupt twice in default
     asyncio REPL.

   - gh-139783(34): Fix *note inspect.getsourcelines(): 15fc. for the
     case when a decorator is followed by a comment or an empty line.

   - gh-70765(35): *note http.server: 72.: fix default handling of
     HTTP/0.9 requests in *note BaseHTTPRequestHandler: 110f.
     Previously, ‘BaseHTTPRequestHandler.parse_request()’ incorrectly
     waited for headers in the request although those are not supported
     in HTTP/0.9.  Patch by Bénédikt Tran.

   - gh-139391(36): Fix an issue when, on non-Windows platforms, it was
     not possible to gracefully exit a ‘python -m asyncio’ process
     suspended by Ctrl+Z and later resumed by ‘fg(37)’ other than with
     ‘kill(38)’.

   - gh-101828(39): Fix ‘'shift_jisx0213'’, ‘'shift_jis_2004'’,
     ‘'euc_jisx0213'’ and ‘'euc_jis_2004'’ codecs truncating null chars
     as they were treated as part of multi-character sequences.

   - gh-139246(40): fix: paste zero-width in default repl width is
     wrong.

   - gh-90949(41): Add *note SetAllocTrackerActivationThreshold(): 15fd.
     and *note SetAllocTrackerMaximumAmplification(): 15fe. to *note
     xmlparser: 15ff. objects to prevent use of disproportional amounts
     of dynamic memory from within an Expat parser.  Patch by Bénédikt
     Tran.

   - gh-139065(42): Fix trailing space before a wrapped long word if the
     line length is exactly 'width' in *note textwrap: ec.

   - gh-138993(43): Dedent *note credits: 15d5. text.

   - gh-138859(44): Fix generic type parameterization raising a *note
     TypeError: 2c3. when omitting a ‘ParamSpec’ that has a default
     which is not a list of types.

   - gh-138775(45): Use of ‘python -m’ with *note base64: e. has been
     fixed to detect input from a terminal so that it properly notices
     EOF.

   - gh-98896(46): Fix a failure in multiprocessing resource_tracker
     when SharedMemory names contain colons.  Patch by Rani Pinchuk.

   - gh-75989(47): *note tarfile.TarFile.extractall(): 431. and *note
     tarfile.TarFile.extract(): 432. now overwrite symlinks when
     extracting hardlinks.  (Contributed by Alexander Enrique Urieles
     Nieto in gh-75989(48).)

   - gh-83424(49): Allows creating a *note ctypes.CDLL: 9f4. without
     name when passing a handle as an argument.

   - gh-136234(50): Fix *note asyncio.WriteTransport.writelines(): 1600.
     to be robust to connection failure, by using the same behavior as
     *note write(): 1601.

   - gh-136057(51): Fixed the bug in *note pdb: a5. and *note bdb: f.
     where ‘next’ and ‘step’ can’t go over the line if a loop exists in
     the line.

   - gh-135307(52): *note email: 3b.: Fix exception in ‘set_content()’
     when encoding text and max_line_length is set to ‘0’ or ‘None’
     (unlimited).

   - gh-134453(53): Fixed *note subprocess.Popen.communicate(): 15f2.
     ‘input=’ handling of *note memoryview: 2eb. instances that were
     non-byte shaped on POSIX platforms.  Those are now properly cast to
     a byte shaped view instead of truncating the input.  Windows
     platforms did not have this bug.

   - gh-102431(54): Clarify constraints for “logical” arguments in
     methods of *note decimal.Context: 10f3.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/74389

   (2) https://github.com/python/cpython/issues/87512

   (3) https://github.com/python/cpython/issues/141473

   (4) https://github.com/python/cpython/issues/59000

   (5) https://github.com/python/cpython/issues/141570

   (6) https://github.com/python/cpython/issues/141659

   (7) https://github.com/python/cpython/issues/141497

   (8) https://github.com/python/cpython/issues/140938

   (9) https://github.com/python/cpython/issues/124111

   (10) https://github.com/python/cpython/issues/137109

   (11) https://github.com/python/cpython/issues/141314

   (12) https://github.com/python/cpython/issues/141311

   (13) https://github.com/python/cpython/issues/141141

   (14) https://github.com/python/cpython/issues/140911

   (15) https://github.com/python/cpython/issues/140797

   (16) https://github.com/python/cpython/issues/140815

   (17) https://github.com/python/cpython/issues/100218

   (18) https://github.com/python/cpython/issues/140875

   (19) https://github.com/python/cpython/issues/140734

   (20) https://github.com/python/cpython/issues/140874

   (21) https://github.com/python/cpython/issues/140691

   (22) https://github.com/python/cpython/issues/103847

   (23) https://github.com/python/cpython/issues/140590

   (24) https://github.com/python/cpython/issues/140634

   (25) https://github.com/python/cpython/issues/140633

   (26) https://github.com/python/cpython/issues/140593

   (27) https://github.com/python/cpython/issues/140607

   (28) https://github.com/python/cpython/issues/138162

   (29) https://github.com/python/cpython/issues/140474

   (30) https://github.com/python/cpython/issues/140272

   (31) https://github.com/python/cpython/issues/140041

   (32) https://github.com/python/cpython/issues/139905

   (33) https://github.com/python/cpython/issues/139845

   (34) https://github.com/python/cpython/issues/139783

   (35) https://github.com/python/cpython/issues/70765

   (36) https://github.com/python/cpython/issues/139391

   (37) https://manpages.debian.org/fg

   (38) https://manpages.debian.org/kill

   (39) https://github.com/python/cpython/issues/101828

   (40) https://github.com/python/cpython/issues/139246

   (41) https://github.com/python/cpython/issues/90949

   (42) https://github.com/python/cpython/issues/139065

   (43) https://github.com/python/cpython/issues/138993

   (44) https://github.com/python/cpython/issues/138859

   (45) https://github.com/python/cpython/issues/138775

   (46) https://github.com/python/cpython/issues/98896

   (47) https://github.com/python/cpython/issues/75989

   (48) https://github.com/python/cpython/issues/75989

   (49) https://github.com/python/cpython/issues/83424

   (50) https://github.com/python/cpython/issues/136234

   (51) https://github.com/python/cpython/issues/136057

   (52) https://github.com/python/cpython/issues/135307

   (53) https://github.com/python/cpython/issues/134453

   (54) https://github.com/python/cpython/issues/102431


File: python.info,  Node: IDLE<4>,  Next: Documentation<4>,  Prev: Library<4>,  Up: Python 3 13 10 final

1.23.4.5 IDLE
.............

   - gh-96491(1): Deduplicate version number in IDLE shell title bar
     after saving to a file.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96491


File: python.info,  Node: Documentation<4>,  Next: Core and Builtins<4>,  Prev: IDLE<4>,  Up: Python 3 13 10 final

1.23.4.6 Documentation
......................

   - gh-141994(1): *note xml.sax.handler: 12a.: Make Documentation of
     *note xml.sax.handler.feature_external_ges: 1604. warn of opening
     up to external entity attacks(2).  Patch by Sebastian Pipping.

   - gh-140578(3): Remove outdated sencence in the documentation for
     *note multiprocessing: 94, that implied that *note
     concurrent.futures.ThreadPoolExecutor: 745. did not exist.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/141994

   (2) https://en.wikipedia.org/wiki/XML_external_entity_attack

   (3) https://github.com/python/cpython/issues/140578


File: python.info,  Node: Core and Builtins<4>,  Next: C API<2>,  Prev: Documentation<4>,  Up: Python 3 13 10 final

1.23.4.7 Core and Builtins
..........................

   - gh-142048(1): Fix quadratically increasing garbage collection
     delays in free-threaded build.

   - gh-141930(2): When importing a module, use Python’s regular file
     object to ensure that writes to ‘.pyc’ files are complete or an
     appropriate error is raised.

   - gh-120158(3): Fix inconsistent state when enabling or disabling
     monitoring events too many times.

   - gh-141579(4): Fix *note sys.activate_stack_trampoline(): 472. to
     properly support the ‘perf_jit’ backend.  Patch by Pablo Galindo.

   - gh-141312(5): Fix the assertion failure in the ‘__setstate__’
     method of the range iterator when a non-integer argument is passed.
     Patch by Sergey Miryanov.

   - gh-140939(6): Fix memory leak when *note bytearray: 2ea. or *note
     bytes: 1c2. is formated with the ‘%*b’ format with a large width
     that results in a *note MemoryError: 15ab.

   - gh-140530(7): Fix a reference leak when ‘raise exc from cause’
     fails.  Patch by Bénédikt Tran.

   - gh-140576(8): Fixed crash in *note tokenize.generate_tokens(): 4dd.
     in case of specific incorrect input.  Patch by Mikhail Efimov.

   - gh-140551(9): Fixed crash in *note dict: 256. if *note
     dict.clear(): 15bb. is called at the lookup stage.  Patch by
     Mikhail Efimov and Inada Naoki.

   - gh-140471(10): Fix potential buffer overflow in *note ast.AST: 1a6.
     node initialization when encountering malformed *note _fields:
     1606. containing non-*note str: 44f.

   - gh-140406(11): Fix memory leak when an object’s *note __hash__():
     b14. method returns an object that isn’t an *note int: 257.

   - gh-140306(12): Fix memory leaks in cross-interpreter channel
     operations and shared namespace handling.

   - gh-140301(13): Fix memory leak of ‘PyConfig’ in subinterpreters.

   - gh-140000(14): Fix potential memory leak when a reference cycle
     exists between an instance of *note typing.TypeAliasType: 458,
     *note typing.TypeVar: 15d, *note typing.ParamSpec: 15e, or *note
     typing.TypeVarTuple: 15f. and its ‘__name__’ attribute.  Patch by
     Mikhail Efimov.

   - gh-139748(15): Fix reference leaks in error branches of functions
     accepting path strings or bytes such as *note compile(): 192. and
     *note os.system(): 14ac.  Patch by Bénédikt Tran.

   - gh-139516(16): Fix lambda colon erroneously start format spec in
     f-string in tokenizer.

   - gh-139640(17): Fix swallowing some syntax warnings in different
     modules if they accidentally have the same message and are emitted
     from the same line.  Fix duplicated warnings in the ‘finally’
     block.

   - gh-137400(18): Fix a crash in the *note free threading: 15b3. build
     when disabling profiling or tracing across all threads with *note
     PyEval_SetProfileAllThreads(): 562. or *note
     PyEval_SetTraceAllThreads(): 425. or their Python equivalents *note
     threading.settrace_all_threads(): 4cb. and *note
     threading.setprofile_all_threads(): 4cc.

   - gh-133400(19): Fixed Ctrl+D (^D) behavior in _pyrepl module to
     match old pre-3.13 REPL behavior.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/142048

   (2) https://github.com/python/cpython/issues/141930

   (3) https://github.com/python/cpython/issues/120158

   (4) https://github.com/python/cpython/issues/141579

   (5) https://github.com/python/cpython/issues/141312

   (6) https://github.com/python/cpython/issues/140939

   (7) https://github.com/python/cpython/issues/140530

   (8) https://github.com/python/cpython/issues/140576

   (9) https://github.com/python/cpython/issues/140551

   (10) https://github.com/python/cpython/issues/140471

   (11) https://github.com/python/cpython/issues/140406

   (12) https://github.com/python/cpython/issues/140306

   (13) https://github.com/python/cpython/issues/140301

   (14) https://github.com/python/cpython/issues/140000

   (15) https://github.com/python/cpython/issues/139748

   (16) https://github.com/python/cpython/issues/139516

   (17) https://github.com/python/cpython/issues/139640

   (18) https://github.com/python/cpython/issues/137400

   (19) https://github.com/python/cpython/issues/133400


File: python.info,  Node: C API<2>,  Prev: Core and Builtins<4>,  Up: Python 3 13 10 final

1.23.4.8 C API
..............

   - gh-140042(1): Removed the sqlite3_shutdown call that could cause
     closing connections for sqlite when used with multiple sub
     interpreters.

   - gh-140487(2): Fix *note Py_RETURN_NOTIMPLEMENTED: 1608. in limited
     C API 3.11 and older: don’t treat ‘Py_NotImplemented’ as immortal.
     Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/140042

   (2) https://github.com/python/cpython/issues/140487


File: python.info,  Node: Python 3 13 9 final,  Next: Python 3 13 8 final,  Prev: Python 3 13 10 final,  Up: Changelog

1.23.5 Python 3.13.9 final
--------------------------

'Release date: 2025-10-14'

* Menu:

* Library: Library<5>.


File: python.info,  Node: Library<5>,  Up: Python 3 13 9 final

1.23.5.1 Library
................

   - gh-139783(1): Fix *note inspect.getsourcelines(): 15fc. for the
     case when a decorator is followed by a comment or an empty line.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139783


File: python.info,  Node: Python 3 13 8 final,  Next: Python 3 13 7 final,  Prev: Python 3 13 9 final,  Up: Changelog

1.23.6 Python 3.13.8 final
--------------------------

'Release date: 2025-10-07'

* Menu:

* macOS: macOS<2>.
* Windows: Windows<3>.
* Tools/Demos: Tools/Demos<3>.
* Tests: Tests<4>.
* Security: Security<5>.
* Library: Library<6>.
* Core and Builtins: Core and Builtins<5>.
* C API: C API<3>.
* Build: Build<3>.


File: python.info,  Node: macOS<2>,  Next: Windows<3>,  Up: Python 3 13 8 final

1.23.6.1 macOS
..............

   - gh-124111(1): Update macOS installer to use Tcl/Tk 8.6.17.

   - gh-139573(2): Updated bundled version of OpenSSL to 3.0.18.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124111

   (2) https://github.com/python/cpython/issues/139573


File: python.info,  Node: Windows<3>,  Next: Tools/Demos<3>,  Prev: macOS<2>,  Up: Python 3 13 8 final

1.23.6.2 Windows
................

   - gh-139573(1): Updated bundled version of OpenSSL to 3.0.18.

   - gh-138896(2): Fix error installing C runtime on non-updated Windows
     machines

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139573

   (2) https://github.com/python/cpython/issues/138896


File: python.info,  Node: Tools/Demos<3>,  Next: Tests<4>,  Prev: Windows<3>,  Up: Python 3 13 8 final

1.23.6.3 Tools/Demos
....................

   - gh-139330(1): SBOM generation tool didn’t cross-check the version
     and checksum values against the ‘Modules/expat/refresh.sh’ script,
     leading to the values becoming out-of-date during routine updates.

   - gh-137873(2): The iOS test runner has been simplified, resolving
     some issues that have been observed using the runner in GitHub
     Actions and Azure Pipelines test environments.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139330

   (2) https://github.com/python/cpython/issues/137873


File: python.info,  Node: Tests<4>,  Next: Security<5>,  Prev: Tools/Demos<3>,  Up: Python 3 13 8 final

1.23.6.4 Tests
..............

   - gh-139208(1): Fix regrtest ‘--fast-ci --verbose’: don’t ignore the
     ‘--verbose’ option anymore.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139208


File: python.info,  Node: Security<5>,  Next: Library<6>,  Prev: Tests<4>,  Up: Python 3 13 8 final

1.23.6.5 Security
.................

   - gh-139400(1): *note xml.parsers.expat: 126.: Make sure that parent
     Expat parsers are only garbage-collected once they are no longer
     referenced by subparsers created by *note
     ExternalEntityParserCreate(): 15b0.  Patch by Sebastian Pipping.

   - gh-139283(2): *note sqlite3: cf.: correctly handle maximum number
     of rows to fetch in *note Cursor.fetchmany: 1611. and reject
     negative values for *note Cursor.arraysize: 1612.  Patch by
     Bénédikt Tran.

   - gh-135661(3): Fix CDATA section parsing in *note
     html.parser.HTMLParser: 87e. according to the HTML5 standard: ‘]
     ]>’ and ‘]] >’ no longer end the CDATA section.  Add private method
     ‘_set_support_cdata()’ which can be used to specify how to parse
     ‘<[CDATA[’ — as a CDATA section in foreign content (SVG or MathML)
     or as a bogus comment in the HTML namespace.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139400

   (2) https://github.com/python/cpython/issues/139283

   (3) https://github.com/python/cpython/issues/135661


File: python.info,  Node: Library<6>,  Next: Core and Builtins<5>,  Prev: Security<5>,  Up: Python 3 13 8 final

1.23.6.6 Library
................

   - gh-139312(1): Upgrade bundled libexpat to 2.7.3

   - gh-139289(2): Do a real lazy-import on *note rlcompleter: bd. in
     *note pdb: a5. and restore the existing completer after importing
     ‘rlcompleter’.

   - gh-139210(3): Fix use-after-free when reporting unknown event in
     *note xml.etree.ElementTree.iterparse(): 273.  Patch by Ken Jin.

   - gh-138860(4): Lazy import *note rlcompleter: bd. in *note pdb: a5.
     to avoid deadlock in subprocess.

   - gh-112729(5): Fix crash when calling ‘_interpreters.create’ when
     the process is out of memory.

   - gh-139076(6): Fix a bug in the *note pydoc: b5. module that was
     hiding functions in a Python module if they were implemented in an
     extension module and the module did not have ‘__all__’.

   - gh-138998(7): Update bundled libexpat to 2.7.2

   - gh-130567(8): Fix possible crash in *note locale.strxfrm(): 1614.
     due to a platform bug on macOS.

   - gh-138779(9): Support device numbers larger than ‘2**63-1’ for the
     *note st_rdev: 1615. field of the *note os.stat_result: 1510.
     structure.

   - gh-128636(10): Fix crash in PyREPL when os.environ is overwritten
     with an invalid value for mac

   - gh-88375(11): Fix normalization of the ‘robots.txt’ rules and URLs
     in the *note urllib.robotparser: 10d. module.  No longer ignore
     trailing ‘?’.  Distinguish raw special characters ‘?’, ‘=’ and ‘&’
     from the percent-encoded ones.

   - gh-138515(12): *note email: 3b. is added to Emscripten build.

   - gh-111788(13): Fix parsing errors in the *note urllib.robotparser:
     10d. module.  Don’t fail trying to parse weird paths.  Don’t fail
     trying to decode non-UTF-8 ‘robots.txt’ files.

   - gh-138432(14): *note zoneinfo.reset_tzpath(): 1616. will now
     convert any *note os.PathLike: c72. objects it receives into
     strings before adding them to ‘TZPATH’.  It will raise ‘TypeError’
     if anything other than a string is found after this conversion.  If
     given an ‘os.PathLike’ object that represents a relative path, it
     will now raise ‘ValueError’ instead of ‘TypeError’, and present a
     more informative error message.

   - gh-138008(15): Fix segmentation faults in the *note ctypes: 2a.
     module due to invalid *note argtypes: 1617.  Patch by Dung Nguyen.

   - gh-60462(16): Fix *note locale.strxfrm(): 1614. on Solaris (and
     possibly other platforms).

   - gh-138204(17): Forbid expansion of shared anonymous *note memory
     maps: 90. on Linux, which caused a bus error.

   - gh-138010(18): Fix an issue where defining a class with a *note
     @warnings.deprecated: 160.-decorated base class may not invoke the
     correct *note __init_subclass__(): 634. method in cases involving
     multiple inheritance.  Patch by Brian Schubert.

   - gh-138133(19): Prevent infinite traceback loop when sending CTRL^C
     to Python through ‘strace’.

   - gh-134869(20): Fix an issue where pressing Ctrl+C during tab
     completion in the REPL would leave the autocompletion menu in a
     corrupted state.

   - gh-137317(21): *note inspect.signature(): 73b. now correctly
     handles classes that use a descriptor on a wrapped ‘__init__()’ or
     ‘__new__()’ method.  Contributed by Yongyu Yan.

   - gh-137754(22): Fix import of the *note zoneinfo: 134. module if the
     C implementation of the *note datetime: 30. module is not
     available.

   - gh-137490(23): Handle *note ECANCELED: 1618. in the same way as
     *note EINTR: db5. in *note signal.sigwaitinfo(): dd9. on NetBSD.

   - gh-137477(24): Fix ‘inspect.getblock()’, *note
     inspect.getsourcelines(): 15fc. and *note inspect.getsource():
     1619. for generator expressions.

   - gh-137017(25): Fix *note threading.Thread.is_alive: 957. to remain
     ‘True’ until the underlying OS thread is fully cleaned up.  This
     avoids false negatives in edge cases involving thread monitoring or
     premature ‘threading.Thread.is_alive’ calls.

   - gh-136134(26): ‘SMTP.auth_cram_md5()’ now raises an *note
     SMTPException: fda. instead of a *note ValueError: 202. if Python
     has been built without MD5 support.  In particular, *note SMTP:
     937. clients will not attempt to use this method even if the remote
     server is assumed to support it.  Patch by Bénédikt Tran.

   - gh-136134(27): *note IMAP4.login_cram_md5: 161a. now raises an
     *note IMAP4.error: 161b. if CRAM-MD5 authentication is not
     supported.  Patch by Bénédikt Tran.

   - gh-135386(28): Fix opening a *note dbm.sqlite3: 35. database for
     reading from read-only file or directory.

   - gh-126631(29): Fix *note multiprocessing: 94. ‘forkserver’ bug
     which prevented ‘__main__’ from being preloaded.

   - gh-123085(30): In a bare call to *note importlib.resources.files():
     491, ensure the caller’s frame is properly detected when
     ‘importlib.resources’ is itself available as a compiled module only
     (no source).

   - gh-118981(31): Fix potential hang in
     ‘multiprocessing.popen_spawn_posix’ that can happen when the child
     proc dies early by closing the child fds right away.

   - gh-78319(32): UTF8 support for the IMAP APPEND command has been
     made RFC compliant.

   - bpo-38735(33): Fix failure when importing a module from the root
     directory on unix-like platforms with sys.pycache_prefix set.

   - bpo-41839(34): Allow negative priority values from *note
     os.sched_get_priority_min(): 114d. and *note
     os.sched_get_priority_max(): 114c. functions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/139312

   (2) https://github.com/python/cpython/issues/139289

   (3) https://github.com/python/cpython/issues/139210

   (4) https://github.com/python/cpython/issues/138860

   (5) https://github.com/python/cpython/issues/112729

   (6) https://github.com/python/cpython/issues/139076

   (7) https://github.com/python/cpython/issues/138998

   (8) https://github.com/python/cpython/issues/130567

   (9) https://github.com/python/cpython/issues/138779

   (10) https://github.com/python/cpython/issues/128636

   (11) https://github.com/python/cpython/issues/88375

   (12) https://github.com/python/cpython/issues/138515

   (13) https://github.com/python/cpython/issues/111788

   (14) https://github.com/python/cpython/issues/138432

   (15) https://github.com/python/cpython/issues/138008

   (16) https://github.com/python/cpython/issues/60462

   (17) https://github.com/python/cpython/issues/138204

   (18) https://github.com/python/cpython/issues/138010

   (19) https://github.com/python/cpython/issues/138133

   (20) https://github.com/python/cpython/issues/134869

   (21) https://github.com/python/cpython/issues/137317

   (22) https://github.com/python/cpython/issues/137754

   (23) https://github.com/python/cpython/issues/137490

   (24) https://github.com/python/cpython/issues/137477

   (25) https://github.com/python/cpython/issues/137017

   (26) https://github.com/python/cpython/issues/136134

   (27) https://github.com/python/cpython/issues/136134

   (28) https://github.com/python/cpython/issues/135386

   (29) https://github.com/python/cpython/issues/126631

   (30) https://github.com/python/cpython/issues/123085

   (31) https://github.com/python/cpython/issues/118981

   (32) https://github.com/python/cpython/issues/78319

   (33) https://bugs.python.org/issue?@action=redirect&bpo=38735

   (34) https://bugs.python.org/issue?@action=redirect&bpo=41839


File: python.info,  Node: Core and Builtins<5>,  Next: C API<3>,  Prev: Library<6>,  Up: Python 3 13 8 final

1.23.6.7 Core and Builtins
..........................

   - gh-134466(1): Don’t run PyREPL in a degraded environment where
     setting termios attributes is not allowed.

   - gh-71810(2): Raise *note OverflowError: 888. for ‘(-1).to_bytes()’
     for signed conversions when bytes count is zero.  Patch by Sergey B
     Kirpichev.

   - gh-105487(3): Remove non-existent *note __copy__(): 161d, *note
     __deepcopy__(): 161e, and *note __bases__: 14fb. from the *note
     __dir__(): 15b7. entries of *note types.GenericAlias: 7f0.

   - gh-134163(4): Fix a hang when the process is out of memory inside
     an exception handler.

   - gh-138479(5): Fix a crash when a generic object’s
     ‘__typing_subst__’ returns an object that isn’t a *note tuple: 373.

   - gh-137576(6): Fix for incorrect source code being shown in
     tracebacks from the Basic REPL when *note PYTHONSTARTUP: 1003. is
     given.  Patch by Adam Hartz.

   - gh-132744(7): Certain calls now check for runaway recursion and
     respect the system recursion limit.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134466

   (2) https://github.com/python/cpython/issues/71810

   (3) https://github.com/python/cpython/issues/105487

   (4) https://github.com/python/cpython/issues/134163

   (5) https://github.com/python/cpython/issues/138479

   (6) https://github.com/python/cpython/issues/137576

   (7) https://github.com/python/cpython/issues/132744


File: python.info,  Node: C API<3>,  Next: Build<3>,  Prev: Core and Builtins<5>,  Up: Python 3 13 8 final

1.23.6.8 C API
..............

   - gh-87135(1): Attempting to acquire the GIL after runtime
     finalization has begun in a different thread now causes the thread
     to hang rather than terminate, which avoids potential crashes or
     memory corruption caused by attempting to terminate a thread that
     is running code not specifically designed to support termination.
     In most cases this hanging is harmless since the process will soon
     exit anyway.

     While not officially marked deprecated until 3.14,
     ‘PyThread_exit_thread’ is no longer called internally and remains
     solely for interface compatibility.  Its behavior is inconsistent
     across platforms, and it can only be used safely in the unlikely
     case that every function in the entire call stack has been designed
     to support the platform-dependent termination mechanism.  It is
     recommended that users of this function change their design to not
     require thread termination.  In the unlikely case that thread
     termination is needed and can be done safely, users may migrate to
     calling platform-specific APIs such as ‘pthread_exit’ (POSIX) or
     ‘_endthreadex’ (Windows) directly.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87135


File: python.info,  Node: Build<3>,  Prev: C API<3>,  Up: Python 3 13 8 final

1.23.6.9 Build
..............

   - gh-135734(1): Python can correctly be configured and built with
     ‘./configure --enable-optimizations --disable-test-modules’.
     Previously, the profile data generation step failed due to PGO
     tests where immortalization couldn’t be properly suppressed.  Patch
     by Bénédikt Tran.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135734


File: python.info,  Node: Python 3 13 7 final,  Next: Python 3 13 6 final,  Prev: Python 3 13 8 final,  Up: Changelog

1.23.7 Python 3.13.7 final
--------------------------

'Release date: 2025-08-14'

* Menu:

* Library: Library<7>.
* Documentation: Documentation<5>.
* Core and Builtins: Core and Builtins<6>.


File: python.info,  Node: Library<7>,  Next: Documentation<5>,  Up: Python 3 13 7 final

1.23.7.1 Library
................

   - gh-137583(1): Fix a deadlock introduced in 3.13.6 when a call to
     *note ssl.SSLSocket.recv: dd2. was blocked in one thread, and then
     another method on the object (such as *note ssl.SSLSocket.send:
     dd5.) was subsequently called in another thread.

   - gh-137044(2): Return large limit values as positive integers
     instead of negative integers in *note resource.getrlimit(): 1623.
     Accept large values and reject negative values (except *note
     RLIM_INFINITY: 1624.) for limits in *note resource.setrlimit():
     1625.

   - gh-136914(3): Fix retrieval of *note doctest.DocTest.lineno: 1626.
     for objects decorated with *note functools.cache(): 1627. or *note
     functools.cached_property: 544.

   - gh-131788(4): Make ‘ResourceTracker.send’ from *note
     multiprocessing: 94. re-entrant safe

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/137583

   (2) https://github.com/python/cpython/issues/137044

   (3) https://github.com/python/cpython/issues/136914

   (4) https://github.com/python/cpython/issues/131788


File: python.info,  Node: Documentation<5>,  Next: Core and Builtins<6>,  Prev: Library<7>,  Up: Python 3 13 7 final

1.23.7.2 Documentation
......................

   - gh-136155(1): We are now checking for fatal errors in EPUB builds
     in CI.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/136155


File: python.info,  Node: Core and Builtins<6>,  Prev: Documentation<5>,  Up: Python 3 13 7 final

1.23.7.3 Core and Builtins
..........................

   - gh-137400(1): Fix a crash in the *note free threading: 15b3. build
     when disabling profiling or tracing across all threads with *note
     PyEval_SetProfileAllThreads(): 562. or *note
     PyEval_SetTraceAllThreads(): 425. or their Python equivalents *note
     threading.settrace_all_threads(): 4cb. and *note
     threading.setprofile_all_threads(): 4cc.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/137400


File: python.info,  Node: Python 3 13 6 final,  Next: Python 3 13 5 final,  Prev: Python 3 13 7 final,  Up: Changelog

1.23.8 Python 3.13.6 final
--------------------------

'Release date: 2025-08-06'

* Menu:

* macOS: macOS<3>.
* Windows: Windows<4>.
* Tools/Demos: Tools/Demos<4>.
* Tests: Tests<5>.
* Security: Security<6>.
* Library: Library<8>.
* Documentation: Documentation<6>.
* Core and Builtins: Core and Builtins<7>.
* Build: Build<4>.


File: python.info,  Node: macOS<3>,  Next: Windows<4>,  Up: Python 3 13 6 final

1.23.8.1 macOS
..............

   - gh-137450(1): macOS installer shell path management improvements:
     separate the installer ‘Shell profile updater’ postinstall script
     from the ‘Update Shell Profile.command’ to enable more robust error
     handling.

   - gh-137134(2): Update macOS installer to ship with SQLite version
     3.50.4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/137450

   (2) https://github.com/python/cpython/issues/137134


File: python.info,  Node: Windows<4>,  Next: Tools/Demos<4>,  Prev: macOS<3>,  Up: Python 3 13 6 final

1.23.8.2 Windows
................

   - gh-137134(1): Update Windows installer to ship with SQLite 3.50.4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/137134


File: python.info,  Node: Tools/Demos<4>,  Next: Tests<5>,  Prev: Windows<4>,  Up: Python 3 13 6 final

1.23.8.3 Tools/Demos
....................

   - gh-135968(1): Stubs for ‘strip’ are now provided as part of an iOS
     install.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135968


File: python.info,  Node: Tests<5>,  Next: Security<6>,  Prev: Tools/Demos<4>,  Up: Python 3 13 6 final

1.23.8.4 Tests
..............

   - gh-135966(1): The iOS testbed now handles the ‘app_packages’ folder
     as a site directory.

   - gh-135494(2): Fix regrtest to support excluding tests from ‘--pgo’
     tests.  Patch by Victor Stinner.

   - gh-135489(3): Show verbose output for failing tests during PGO
     profiling step with –enable-optimizations.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135966

   (2) https://github.com/python/cpython/issues/135494

   (3) https://github.com/python/cpython/issues/135489


File: python.info,  Node: Security<6>,  Next: Library<8>,  Prev: Tests<5>,  Up: Python 3 13 6 final

1.23.8.5 Security
.................

   - gh-135661(1): Fix parsing start and end tags in *note
     html.parser.HTMLParser: 87e. according to the HTML5 standard.

        * Whitespaces no longer accepted between ‘</’ and the tag name.
          E.g.  ‘</ script>’ does not end the script section.

        * Vertical tabulation (‘\v’) and non-ASCII whitespaces no longer
          recognized as whitespaces.  The only whitespaces are
          ‘\t\n\r\f’ and space.

        * Null character (U+0000) no longer ends the tag name.

        * Attributes and slashes after the tag name in end tags are now
          ignored, instead of terminating after the first ‘>’ in quoted
          attribute value.  E.g.  ‘</script/foo=">"/>’.

        * Multiple slashes and whitespaces between the last attribute
          and closing ‘>’ are now ignored in both start and end tags.
          E.g.  ‘<a foo=bar/ //>’.

        * Multiple ‘=’ between attribute name and value are no longer
          collapsed.  E.g.  ‘<a foo==bar>’ produces attribute “foo” with
          value “=bar”.

   - gh-102555(2): Fix comment parsing in *note html.parser.HTMLParser:
     87e. according to the HTML5 standard.  ‘--!>’ now ends the comment.
     ‘-- >’ no longer ends the comment.  Support abnormally ended empty
     comments ‘<-->’ and ‘<--->’.

   - gh-135462(3): Fix quadratic complexity in processing specially
     crafted input in *note html.parser.HTMLParser: 87e.  End-of-file
     errors are now handled according to the HTML5 specs – comments and
     declarations are automatically closed, tags are ignored.

   - gh-118350(4): Fix support of escapable raw text mode (elements
     “textarea” and “title”) in *note html.parser.HTMLParser: 87e.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135661

   (2) https://github.com/python/cpython/issues/102555

   (3) https://github.com/python/cpython/issues/135462

   (4) https://github.com/python/cpython/issues/118350


File: python.info,  Node: Library<8>,  Next: Documentation<6>,  Prev: Security<6>,  Up: Python 3 13 6 final

1.23.8.6 Library
................

   - gh-132710(1): If possible, ensure that *note uuid.getnode(): bc5.
     returns the same result even across different processes.
     Previously, the result was constant only within the same process.
     Patch by Bénédikt Tran.

   - gh-137273(2): Fix debug assertion failure in *note
     locale.setlocale(): 2db. on Windows.

   - gh-137257(3): Bump the version of pip bundled in ensurepip to
     version 25.2

   - gh-81325(4): *note tarfile.TarFile: 1255. now accepts a *note
     path-like: 2a0. when working on a tar archive.  (Contributed by
     Alexander Enrique Urieles Nieto in gh-81325(5).)

   - gh-130522(6): Fix unraisable *note TypeError: 2c3. raised during
     *note interpreter shutdown: 14e. in the *note threading: ed.
     module.

   - gh-130577(7): *note tarfile: de. now validates archives to ensure
     member offsets are non-negative.  (Contributed by Alexander Enrique
     Urieles Nieto in gh-130577(8).)

   - gh-136549(9): Fix signature of *note threading.excepthook(): 851.

   - gh-136523(10): Fix *note wave.Wave_write: 2b7. emitting an
     unraisable when open raises.

   - gh-52876(11): Add missing ‘keepends’ (default ‘True’) parameter to
     ‘codecs.StreamReaderWriter.readline()’ and
     ‘codecs.StreamReaderWriter.readlines()’.

   - gh-85702(12): If ‘zoneinfo._common.load_tzdata’ is given a package
     without a resource a *note zoneinfo.ZoneInfoNotFoundError: 1631. is
     raised rather than a *note PermissionError: d6b.  Patch by Victor
     Stinner.

   - gh-134759(13): Fix *note UnboundLocalError: 1586. in *note
     email.message.Message.get_payload(): 1212. when the payload to
     decode is a *note bytes: 1c2. object.  Patch by Kliment Lamonov.

   - gh-136028(14): Fix parsing month names containing “İ” (U+0130,
     LATIN CAPITAL LETTER I WITH DOT ABOVE) in *note time.strptime():
     147b.  This affects locales az_AZ, ber_DZ, ber_MA and crh_UA.

   - gh-135995(15): In the palmos encoding, make byte ‘0x9b’ decode to
     ‘›’ (U+203A - SINGLE RIGHT-POINTING ANGLE QUOTATION MARK).

   - gh-53203(16): Fix *note time.strptime(): 147b. for ‘%c’ and ‘%x’
     formats on locales byn_ER, wal_ET and lzh_TW, and for ‘%X’ format
     on locales ar_SA, bg_BG and lzh_TW.

   - gh-91555(17): An earlier change, which was introduced in 3.13.4,
     has been reverted.  It disabled logging for a logger during
     handling of log messages for that logger.  Since the reversion, the
     behaviour should be as it was before 3.13.4.

   - gh-135878(18): Fixes a crash of *note types.SimpleNamespace: 1d1.
     on *note free threading: 15b3. builds, when several threads were
     calling its *note __repr__(): 61f. method at the same time.

   - gh-135836(19): Fix *note IndexError: 1585. in *note
     asyncio.loop.create_connection(): 606. that could occur when
     non-*note OSError: 41a. exception is raised during connection and
     socket’s ‘close()’ raises ‘OSError’.

   - gh-135836(20): Fix *note IndexError: 1585. in *note
     asyncio.loop.create_connection(): 606. that could occur when the
     Happy Eyeballs algorithm resulted in an empty exceptions list
     during connection attempts.

   - gh-135855(21): Raise *note TypeError: 2c3. instead of *note
     SystemError: 578. when ‘_interpreters.set___main___attrs()’ is
     passed a non-dict object.  Patch by Brian Schubert.

   - gh-135815(22): *note netrc: 9b.: skip security checks if *note
     os.getuid(): 1632. is missing.  Patch by Bénédikt Tran.

   - gh-135640(23): Address bug where it was possible to call *note
     xml.etree.ElementTree.ElementTree.write(): aaa. on an ElementTree
     object with an invalid root element.  This behavior blanked the
     file passed to ‘write’ if it already existed.

   - gh-135444(24): Fix *note asyncio.DatagramTransport.sendto(): 1af.
     to account for datagram header size when data cannot be sent.

   - gh-135497(25): Fix *note os.getlogin(): 1633. failing for longer
     usernames on BSD-based platforms.

   - gh-135487(26): Fix ‘reprlib.Repr.repr_int()’ when given integers
     with more than *note sys.get_int_max_str_digits(): 1634. digits.
     Patch by Bénédikt Tran.

   - gh-135335(27): *note multiprocessing: 94.: Flush ‘stdout’ and
     ‘stderr’ after preloading modules in the ‘forkserver’.

   - gh-135244(28): *note uuid: 110.: when the MAC address cannot be
     determined, the 48-bit node ID is now generated with a
     cryptographically-secure pseudo-random number generator (CSPRNG) as
     per RFC 9562, §6.10.3(29).  This affects *note uuid1(): bc6.

   - gh-135069(30): Fix the “Invalid error handling” exception in
     ‘encodings.idna.IncrementalDecoder’ to correctly replace the
     ‘errors’ parameter.

   - gh-134698(31): Fix a crash when calling methods of *note
     ssl.SSLContext: 294. or *note ssl.SSLSocket: 8f3. across multiple
     threads.

   - gh-132124(32): On POSIX-compliant systems,
     ‘multiprocessing.util.get_temp_dir()’ now ignores ‘TMPDIR’ (and
     similar environment variables) if the path length of ‘AF_UNIX’
     socket files exceeds the platform-specific maximum length when
     using the 'forkserver' start method.  Patch by Bénédikt Tran.

   - gh-133439(33): Fix dot commands with trailing spaces are mistaken
     for multi-line SQL statements in the sqlite3 command-line
     interface.

   - gh-132969(34): Prevent the *note ProcessPoolExecutor: 8f7. executor
     thread, which remains running when *note shutdown(wait=False): 8f6,
     from attempting to adjust the pool’s worker processes after the
     object state has already been reset during shutdown.  A combination
     of conditions, including a worker process having terminated
     abormally, resulted in an exception and a potential hang when the
     still-running executor thread attempted to replace dead workers
     within the pool.

   - gh-130664(35): Support the ‘'_'’ digit separator in formatting of
     the integral part of *note Decimal: 29d.’s.  Patch by Sergey B
     Kirpichev.

   - gh-85702(36): If ‘zoneinfo._common.load_tzdata’ is given a package
     without a resource a ‘ZoneInfoNotFoundError’ is raised rather than
     a *note IsADirectoryError: 1097.

   - gh-130664(37): Handle corner-case for *note Fraction: 1e7.’s
     formatting: treat zero-padding (preceding the width field by a zero
     (‘'0'’) character) as an equivalent to a fill character of ‘'0'’
     with an alignment type of ‘'='’, just as in case of *note float:
     2f7.’s.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/132710

   (2) https://github.com/python/cpython/issues/137273

   (3) https://github.com/python/cpython/issues/137257

   (4) https://github.com/python/cpython/issues/81325

   (5) https://github.com/python/cpython/issues/81325

   (6) https://github.com/python/cpython/issues/130522

   (7) https://github.com/python/cpython/issues/130577

   (8) https://github.com/python/cpython/issues/130577

   (9) https://github.com/python/cpython/issues/136549

   (10) https://github.com/python/cpython/issues/136523

   (11) https://github.com/python/cpython/issues/52876

   (12) https://github.com/python/cpython/issues/85702

   (13) https://github.com/python/cpython/issues/134759

   (14) https://github.com/python/cpython/issues/136028

   (15) https://github.com/python/cpython/issues/135995

   (16) https://github.com/python/cpython/issues/53203

   (17) https://github.com/python/cpython/issues/91555

   (18) https://github.com/python/cpython/issues/135878

   (19) https://github.com/python/cpython/issues/135836

   (20) https://github.com/python/cpython/issues/135836

   (21) https://github.com/python/cpython/issues/135855

   (22) https://github.com/python/cpython/issues/135815

   (23) https://github.com/python/cpython/issues/135640

   (24) https://github.com/python/cpython/issues/135444

   (25) https://github.com/python/cpython/issues/135497

   (26) https://github.com/python/cpython/issues/135487

   (27) https://github.com/python/cpython/issues/135335

   (28) https://github.com/python/cpython/issues/135244

   (29) 
https://datatracker.ietf.org/doc/html/rfc9562.html#section-6.10-3

   (30) https://github.com/python/cpython/issues/135069

   (31) https://github.com/python/cpython/issues/134698

   (32) https://github.com/python/cpython/issues/132124

   (33) https://github.com/python/cpython/issues/133439

   (34) https://github.com/python/cpython/issues/132969

   (35) https://github.com/python/cpython/issues/130664

   (36) https://github.com/python/cpython/issues/85702

   (37) https://github.com/python/cpython/issues/130664


File: python.info,  Node: Documentation<6>,  Next: Core and Builtins<7>,  Prev: Library<8>,  Up: Python 3 13 6 final

1.23.8.7 Documentation
......................

   - gh-135171(1): Document that the *note iterator: 1ac. for the
     leftmost ‘for’ clause in the generator expression is created
     immediately.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135171


File: python.info,  Node: Core and Builtins<7>,  Next: Build<4>,  Prev: Documentation<6>,  Up: Python 3 13 6 final

1.23.8.8 Core and Builtins
..........................

   - gh-58124(1): Fix name of the Python encoding in Unicode errors of
     the code page codec: use “cp65000” and “cp65001” instead of
     “CP_UTF7” and “CP_UTF8” which are not valid Python code names.
     Patch by Victor Stinner.

   - gh-137314(2): Fixed a regression where raw f-strings incorrectly
     interpreted escape sequences in format specifications.  Raw
     f-strings now properly preserve literal backslashes in format
     specs, matching the behavior from Python 3.11.  For example,
     ‘rf"{obj:\xFF}"’ now correctly produces ‘'\\xFF'’ instead of ‘'ÿ'’.
     Patch by Pablo Galindo.

   - gh-136541(3): Fix some issues with the perf trampolines on x86-64
     and aarch64.  The trampolines were not being generated correctly
     for some cases, which could lead to the perf integration not
     working correctly.  Patch by Pablo Galindo.

   - gh-109700(4): Fix memory error handling in *note
     PyDict_SetDefault(): 341.

   - gh-78465(5): Fix error message for ‘cls.__new__(cls, ...)’ where
     ‘cls’ is not instantiable builtin or extension type (with ‘tp_new’
     set to ‘NULL’).

   - gh-135871(6): Non-blocking mutex lock attempts now return
     immediately when the lock is busy instead of briefly spinning in
     the *note free threading: 15b3. build.

   - gh-135607(7): Fix potential *note weakref: 114. races in an
     object’s destructor on the *note free threaded: 15b3. build.

   - gh-135496(8): Fix typo in the f-string conversion type error
     (“exclamanation” -> “exclamation”).

   - gh-130077(9): Properly raise custom syntax errors when incorrect
     syntax containing names that are prefixes of soft keywords is
     encountered.  Patch by Pablo Galindo.

   - gh-135148(10): Fixed a bug where f-string debug expressions (using
     =) would incorrectly strip out parts of strings containing escaped
     quotes and # characters.  Patch by Pablo Galindo.

   - gh-133136(11): Limit excess memory usage in the *note free
     threading: 15b3. build when a large dictionary or list is resized
     and accessed by multiple threads.

   - gh-132617(12): Fix *note dict.update(): 14b4. modification check
     that could incorrectly raise a “dict mutated during update” error
     when a different dictionary was modified that happens to share the
     same underlying keys object.

   - gh-91153(13): Fix a crash when a *note bytearray: 2ea. is
     concurrently mutated during item assignment.

   - gh-127971(14): Fix off-by-one read beyond the end of a string in
     string search.

   - gh-125723(15): Fix crash with ‘gi_frame.f_locals’ when generator
     frames outlive their generator.  Patch by Mikhail Efimov.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/58124

   (2) https://github.com/python/cpython/issues/137314

   (3) https://github.com/python/cpython/issues/136541

   (4) https://github.com/python/cpython/issues/109700

   (5) https://github.com/python/cpython/issues/78465

   (6) https://github.com/python/cpython/issues/135871

   (7) https://github.com/python/cpython/issues/135607

   (8) https://github.com/python/cpython/issues/135496

   (9) https://github.com/python/cpython/issues/130077

   (10) https://github.com/python/cpython/issues/135148

   (11) https://github.com/python/cpython/issues/133136

   (12) https://github.com/python/cpython/issues/132617

   (13) https://github.com/python/cpython/issues/91153

   (14) https://github.com/python/cpython/issues/127971

   (15) https://github.com/python/cpython/issues/125723


File: python.info,  Node: Build<4>,  Prev: Core and Builtins<7>,  Up: Python 3 13 6 final

1.23.8.9 Build
..............

   - gh-135497(1): Fix the detection of ‘MAXLOGNAME’ in the
     ‘configure.ac’ script.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135497


File: python.info,  Node: Python 3 13 5 final,  Next: Python 3 13 4 final,  Prev: Python 3 13 6 final,  Up: Changelog

1.23.9 Python 3.13.5 final
--------------------------

'Release date: 2025-06-11'

* Menu:

* Windows: Windows<5>.
* Tests: Tests<6>.
* Library: Library<9>.
* Core and Builtins: Core and Builtins<8>.
* C API: C API<4>.


File: python.info,  Node: Windows<5>,  Next: Tests<6>,  Up: Python 3 13 5 final

1.23.9.1 Windows
................

   - gh-135151(1): Avoid distributing modified ‘pyconfig.h’ in the
     traditional installer.  Extension module builds must always specify
     ‘Py_GIL_DISABLED’ when targeting the free-threaded runtime.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135151


File: python.info,  Node: Tests<6>,  Next: Library<9>,  Prev: Windows<5>,  Up: Python 3 13 5 final

1.23.9.2 Tests
..............

   - gh-135120(1): Add ‘test.support.subTests()’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135120


File: python.info,  Node: Library<9>,  Next: Core and Builtins<8>,  Prev: Tests<6>,  Up: Python 3 13 5 final

1.23.9.3 Library
................

   - gh-133967(1): Do not normalize *note locale: 86. name ‘C.UTF-8’ to
     ‘en_US.UTF-8’.

   - gh-135326(2): Restore support of integer-like objects with
     ‘__index__()’ in *note random.getrandbits(): 1048.

   - gh-135321(3): Raise a correct exception for values greater than
     0x7fffffff for the ‘BINSTRING’ opcode in the C implementation of
     *note pickle: a6.

   - gh-135276(4): Backported bugfixes in zipfile.Path from zipp 3.23.
     Fixed ‘.name’, ‘.stem’ and other basename-based properties on
     Windows when working with a zipfile on disk.

   - gh-134151(5): *note email: 3b.: Fix *note TypeError: 2c3. in *note
     email.utils.decode_params(): 163c. when sorting RFC 2231(6)
     continuations that contain an unnumbered section.

   - gh-134152(7): *note email: 3b.: Fix parsing of email message ID
     with invalid domain.

   - gh-127081(8): Fix libc thread safety issues with *note os: a1. by
     replacing ‘getlogin’ with ‘getlogin_r’ re-entrant version.

   - gh-131884(9): Fix formatting issues in *note json.dump(): d6d. when
     both 'indent' and 'skipkeys' are used.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/133967

   (2) https://github.com/python/cpython/issues/135326

   (3) https://github.com/python/cpython/issues/135321

   (4) https://github.com/python/cpython/issues/135276

   (5) https://github.com/python/cpython/issues/134151

   (6) https://datatracker.ietf.org/doc/html/rfc2231.html

   (7) https://github.com/python/cpython/issues/134152

   (8) https://github.com/python/cpython/issues/127081

   (9) https://github.com/python/cpython/issues/131884


File: python.info,  Node: Core and Builtins<8>,  Next: C API<4>,  Prev: Library<9>,  Up: Python 3 13 5 final

1.23.9.4 Core and Builtins
..........................

   - gh-135171(1): Roll back changes to generator and list
     comprehensions that went into 3.13.4 to fix gh-127682(2), but which
     involved semantic and bytecode changes not appropriate for a bugfix
     release.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135171

   (2) https://github.com/python/cpython/issues/127682


File: python.info,  Node: C API<4>,  Prev: Core and Builtins<8>,  Up: Python 3 13 5 final

1.23.9.5 C API
..............

   - gh-134989(1): Fix ‘Py_RETURN_NONE’, ‘Py_RETURN_TRUE’ and
     ‘Py_RETURN_FALSE’ macros in the limited C API 3.11 and older: don’t
     treat ‘Py_None’, ‘Py_True’ and ‘Py_False’ as immortal.  Patch by
     Victor Stinner.

   - gh-134989(2): Implement *note PyObject_DelAttr(): 163f. and *note
     PyObject_DelAttrString(): 1640. as macros in the limited C API 3.12
     and older.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134989

   (2) https://github.com/python/cpython/issues/134989


File: python.info,  Node: Python 3 13 4 final,  Next: Python 3 13 3 final,  Prev: Python 3 13 5 final,  Up: Changelog

1.23.10 Python 3.13.4 final
---------------------------

'Release date: 2025-06-03'

* Menu:

* Windows: Windows<6>.
* Tests: Tests<7>.
* Security: Security<7>.
* Library: Library<10>.
* IDLE: IDLE<5>.
* Documentation: Documentation<7>.
* Library: Library<11>.
* Core and Builtins: Core and Builtins<9>.
* Library: Library<12>.
* Core and Builtins: Core and Builtins<10>.
* C API: C API<5>.
* Build: Build<5>.


File: python.info,  Node: Windows<6>,  Next: Tests<7>,  Up: Python 3 13 4 final

1.23.10.1 Windows
.................

   - gh-130727(1): Fix a race in internal calls into WMI that can result
     in an “invalid handle” exception under high load.  Patch by Chris
     Eibl.

   - gh-76023(2): Make *note os.path.realpath(): 225. ignore Windows
     error 1005 when in non-strict mode.

   - gh-133626(3): Ensures packages are not accidentally bundled into
     the traditional installer.

   - gh-133512(4): Add warnings to *note Python Launcher for Windows:
     5c1. about use of subcommands belonging to the Python install
     manager.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/130727

   (2) https://github.com/python/cpython/issues/76023

   (3) https://github.com/python/cpython/issues/133626

   (4) https://github.com/python/cpython/issues/133512


File: python.info,  Node: Tests<7>,  Next: Security<7>,  Prev: Windows<6>,  Up: Python 3 13 4 final

1.23.10.2 Tests
...............

   - gh-133744(1): Fix multiprocessing interrupt test.  Add an event to
     synchronize the parent process with the child process: wait until
     the child process starts sleeping.  Patch by Victor Stinner.

   - gh-133639(2): Fix ‘TestPyReplAutoindent.test_auto_indent_default()’
     doesn’t run ‘input_code’.

   - gh-133131(3): The iOS testbed will now select the most recently
     released “SE-class” device for testing if a device isn’t explicitly
     specified.

   - gh-109981(4): The test helper that counts the list of open file
     descriptors now uses the optimised ‘/dev/fd’ approach on all Apple
     platforms, not just macOS. This avoids crashes caused by guarded
     file descriptors.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/133744

   (2) https://github.com/python/cpython/issues/133639

   (3) https://github.com/python/cpython/issues/133131

   (4) https://github.com/python/cpython/issues/109981


File: python.info,  Node: Security<7>,  Next: Library<10>,  Prev: Tests<7>,  Up: Python 3 13 4 final

1.23.10.3 Security
..................

   - gh-135034(1): Fixes multiple issues that allowed ‘tarfile’
     extraction filters (‘filter="data"’ and ‘filter="tar"’) to be
     bypassed using crafted symlinks and hard links.

     Addresses CVE 2024-12718(2), CVE 2025-4138(3), CVE 2025-4330(4),
     and CVE 2025-4517(5).

   - gh-133767(6): Fix use-after-free in the “unicode-escape” decoder
     with a non-“strict” error handler.

   - gh-128840(7): Short-circuit the processing of long IPv6 addresses
     early in *note ipaddress: 80. to prevent excessive memory
     consumption and a minor denial-of-service.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/135034

   (2) https://www.cve.org/CVERecord?id=CVE-2024-12718

   (3) https://www.cve.org/CVERecord?id=CVE-2025-4138

   (4) https://www.cve.org/CVERecord?id=CVE-2025-4330

   (5) https://www.cve.org/CVERecord?id=CVE-2025-4517

   (6) https://github.com/python/cpython/issues/133767

   (7) https://github.com/python/cpython/issues/128840


File: python.info,  Node: Library<10>,  Next: IDLE<5>,  Prev: Security<7>,  Up: Python 3 13 4 final

1.23.10.4 Library
.................

   - gh-134718(1): *note ast.dump(): 8ed. now only omits ‘None’ and ‘[]’
     values if they are default values.

   - gh-128840(2): Fix parsing long IPv6 addresses with embedded IPv4
     address.

   - gh-134696(3): Built-in HACL* and OpenSSL implementations of hash
     function constructors now correctly accept the same 'documented'
     named arguments.  For instance, *note md5(): 1646. could be
     previously invoked as ‘md5(data=data)’ or ‘md5(string=string)’
     depending on the underlying implementation but these calls were not
     compatible.  Patch by Bénédikt Tran.

   - gh-134210(4): *note curses.window.getch(): 1647. now correctly
     handles signals.  Patch by Bénédikt Tran.

   - gh-80334(5): *note multiprocessing.freeze_support(): 15b2. now
     checks for work on any “spawn” start method platform rather than
     only on Windows.

   - gh-114177(6): Fix *note asyncio: a. to not close subprocess pipes
     which would otherwise error out when the event loop is already
     closed.

   - gh-134152(7): Fixed *note UnboundLocalError: 1586. that could occur
     during *note email: 3b. header parsing if an expected trailing
     delimiter is missing in some contexts.

   - gh-62184(8): Remove import of C implementation of *note io.FileIO:
     1359. from Python implementation which has its own implementation

   - gh-133982(9): Emit *note RuntimeWarning: 1bd. in the Python
     implementation of *note io: 7f. when the *note file-like object:
     1208. is not closed explicitly in the presence of multiple I/O
     layers.

   - gh-133890(10): The *note tarfile: de. module now handles *note
     UnicodeEncodeError: 67a. in the same way as *note OSError: 41a.
     when cannot extract a member.

   - gh-134097(11): Fix interaction of the new *note REPL: 16a. and
     *note -X showrefcount: 176. command line option.

   - gh-133889(12): The generated directory listing page in *note
     http.server.SimpleHTTPRequestHandler: b5c. now only shows the
     decoded path component of the requested URL, and not the query and
     fragment.

   - gh-134098(13): Fix handling paths that end with a percent-encoded
     slash (‘%2f’ or ‘%2F’) in *note
     http.server.SimpleHTTPRequestHandler: b5c.

   - gh-134062(14): *note ipaddress: 80.: fix collisions in *note
     __hash__(): b14. for *note IPv4Network: 1fe. and *note IPv6Network:
     1ff. objects.

   - gh-133745(15): In 3.13.3 we accidentally changed the signature of
     the asyncio ‘create_task()’ family of methods and how it calls a
     custom task factory in a backwards incompatible way.  Since some
     3rd party libraries have already made changes to work around the
     issue that might break if we simply reverted the changes, we’re
     instead changing things to be backwards compatible with 3.13.2
     while still supporting those workarounds for 3.13.3.  In
     particular, the special-casing of ‘name’ and ‘context’ is back
     (until 3.14) and consequently eager tasks may still find that their
     name hasn’t been set before they execute their first yielding
     await.

   - gh-71253(16): Raise *note ValueError: 202. in *note open(): 51f. if
     'opener' returns a negative file-descriptor in the Python
     implementation of *note io: 7f. to match the C implementation.

   - gh-77057(17): Fix handling of invalid markup declarations in *note
     html.parser.HTMLParser: 87e.

   - gh-133489(18): *note random.getrandbits(): 1048. can now generate
     more that 2^31 bits.  *note random.randbytes(): 1648. can now
     generate more that 256 MiB.

   - gh-133290(19): Fix attribute caching issue when setting *note
     ctypes._Pointer._type_: 1649. in the undocumented and deprecated
     ‘ctypes.SetPointerType()’ function and the undocumented
     ‘set_type()’ method.

   - gh-132876(20): ‘ldexp()’ on Windows doesn’t round subnormal results
     before Windows 11, but should.  Python’s *note math.ldexp(): 164a.
     wrapper now does round them, so results may change slightly, in
     rare cases of very small results, on Windows versions before 11.

   - gh-133089(21): Use original timeout value for *note
     subprocess.TimeoutExpired: 15f3. when the func *note
     subprocess.run(): ba4. is called with a timeout instead of
     sometimes a confusing partial remaining time out value used
     internally on the final ‘wait()’.

   - gh-133009(22): *note xml.etree.ElementTree: 125.: Fix a crash in
     *note Element.__deepcopy__: 161e. when the element is concurrently
     mutated.  Patch by Bénédikt Tran.

   - gh-132995(23): Bump the version of pip bundled in ensurepip to
     version 25.1.1

   - gh-132017(24): Fix error when ‘pyrepl’ is suspended, then resumed
     and terminated.

   - gh-132673(25): Fix a crash when using ‘_align_ = 0’ and ‘_fields_ =
     []’ in a *note ctypes.Structure: 1d4.

   - gh-132527(26): Include the valid typecode ‘w’ in the error message
     when an invalid typecode is passed to *note array.array: 1a0.

   - gh-132439(27): Fix ‘PyREPL’ on Windows: characters entered via
     AltGr are swallowed.  Patch by Chris Eibl.

   - gh-132429(28): Fix support of Bluetooth sockets on NetBSD and
     DragonFly BSD.

   - gh-132106(29): *note QueueListener.start: 164b. now raises a *note
     RuntimeError: 195. if the listener is already started.

   - gh-132417(30): Fix a ‘NULL’ pointer dereference when a C function
     called using *note ctypes: 2a. with ‘restype’ *note py_object:
     1486. returns ‘NULL’.

   - gh-132385(31): Fix instance error suggestions trigger potential
     exceptions in *note object.__getattr__(): 4d6. in *note traceback:
     fe.

   - gh-132308(32): A *note traceback.TracebackException: 25c. now
     correctly renders the ‘__context__’ and ‘__cause__’ attributes from
     *note falsey: 164c. *note Exception: 9e5, and the ‘exceptions’
     attribute from falsey *note ExceptionGroup: 1b6.

   - gh-132250(33): Fixed the *note SystemError: 578. in *note cProfile:
     27. when locating the actual C function of a method raises an
     exception.

   - gh-132063(34): Prevent exceptions that evaluate as falsey (namely,
     when their ‘__bool__’ method returns ‘False’ or their ‘__len__’
     method returns 0) from being ignored by *note
     concurrent.futures.ProcessPoolExecutor: 8f7. and *note
     concurrent.futures.ThreadPoolExecutor: 745.

   - gh-119605(35): Respect ‘follow_wrapped’ for ‘__init__()’ and
     ‘__new__()’ methods when getting the class signature for a class
     with *note inspect.signature(): 73b.  Preserve class signature
     after wrapping with *note warnings.deprecated(): 160.  Patch by
     Xuehai Pan.

   - gh-91555(36): Ignore log messages generated during handling of log
     messages, to avoid deadlock or infinite recursion.  [NOTE: This
     change has since been reverted.]

   - gh-131434(37): Improve error reporting for incorrect format in
     *note time.strptime(): 147b.

   - gh-131127(38): Systems using LibreSSL now successfully build.

   - gh-130999(39): Avoid exiting the new REPL and offer suggestions
     even if there are non-string candidates when errors occur.

   - gh-130941(40): Fix *note configparser.ConfigParser: 1c8. parsing
     empty interpolation with ‘allow_no_value’ set to ‘True’.

   - gh-129098(41): Fix REPL traceback reporting when using *note
     compile(): 192. with an inexisting file.  Patch by Bénédikt Tran.

   - gh-130631(42): ‘http.cookiejar.join_header_words()’ is now more
     similar to the original Perl version.  It now quotes the same set
     of characters and always quote values that end with ‘"\n"’.

   - gh-129719(43): Fix missing ‘socket.CAN_RAW_ERR_FILTER’ constant in
     the socket module on Linux systems.  It was missing since Python
     3.11.

   - gh-124096(44): Turn on virtual terminal mode and enable bracketed
     paste in REPL on Windows console.  (If the terminal does not
     support bracketed paste, enabling it does nothing.)

   - gh-122559(45): Remove ‘__reduce__()’ and ‘__reduce_ex__()’ methods
     that always raise *note TypeError: 2c3. in the C implementation of
     *note io.FileIO: 1359, *note io.BufferedReader: 1253, *note
     io.BufferedWriter: 13fe. and *note io.BufferedRandom: 13ff. and
     replace them with default ‘__getstate__()’ methods that raise
     ‘TypeError’.  This restores fine details of behavior of Python 3.11
     and older versions.

   - gh-122179(46): *note hashlib.file_digest(): 647. now raises *note
     BlockingIOError: 1095. when no data is available during
     non-blocking I/O. Before, it added spurious null bytes to the
     digest.

   - gh-86155(47): *note html.parser.HTMLParser.close(): 164d. no longer
     loses data when the ‘<script>’ tag is not closed.  Patch by Waylan
     Limberg.

   - gh-69426(48): Fix *note html.parser.HTMLParser: 87e. to not
     unescape character entities in attribute values if they are
     followed by an ASCII alphanumeric or an equals sign.

   - bpo-44172(49): Keep a reference to original *note curses: 2b.
     windows in subwindows so that the original window does not get
     deleted before subwindows.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134718

   (2) https://github.com/python/cpython/issues/128840

   (3) https://github.com/python/cpython/issues/134696

   (4) https://github.com/python/cpython/issues/134210

   (5) https://github.com/python/cpython/issues/80334

   (6) https://github.com/python/cpython/issues/114177

   (7) https://github.com/python/cpython/issues/134152

   (8) https://github.com/python/cpython/issues/62184

   (9) https://github.com/python/cpython/issues/133982

   (10) https://github.com/python/cpython/issues/133890

   (11) https://github.com/python/cpython/issues/134097

   (12) https://github.com/python/cpython/issues/133889

   (13) https://github.com/python/cpython/issues/134098

   (14) https://github.com/python/cpython/issues/134062

   (15) https://github.com/python/cpython/issues/133745

   (16) https://github.com/python/cpython/issues/71253

   (17) https://github.com/python/cpython/issues/77057

   (18) https://github.com/python/cpython/issues/133489

   (19) https://github.com/python/cpython/issues/133290

   (20) https://github.com/python/cpython/issues/132876

   (21) https://github.com/python/cpython/issues/133089

   (22) https://github.com/python/cpython/issues/133009

   (23) https://github.com/python/cpython/issues/132995

   (24) https://github.com/python/cpython/issues/132017

   (25) https://github.com/python/cpython/issues/132673

   (26) https://github.com/python/cpython/issues/132527

   (27) https://github.com/python/cpython/issues/132439

   (28) https://github.com/python/cpython/issues/132429

   (29) https://github.com/python/cpython/issues/132106

   (30) https://github.com/python/cpython/issues/132417

   (31) https://github.com/python/cpython/issues/132385

   (32) https://github.com/python/cpython/issues/132308

   (33) https://github.com/python/cpython/issues/132250

   (34) https://github.com/python/cpython/issues/132063

   (35) https://github.com/python/cpython/issues/119605

   (36) https://github.com/python/cpython/issues/91555

   (37) https://github.com/python/cpython/issues/131434

   (38) https://github.com/python/cpython/issues/131127

   (39) https://github.com/python/cpython/issues/130999

   (40) https://github.com/python/cpython/issues/130941

   (41) https://github.com/python/cpython/issues/129098

   (42) https://github.com/python/cpython/issues/130631

   (43) https://github.com/python/cpython/issues/129719

   (44) https://github.com/python/cpython/issues/124096

   (45) https://github.com/python/cpython/issues/122559

   (46) https://github.com/python/cpython/issues/122179

   (47) https://github.com/python/cpython/issues/86155

   (48) https://github.com/python/cpython/issues/69426

   (49) https://bugs.python.org/issue?@action=redirect&bpo=44172


File: python.info,  Node: IDLE<5>,  Next: Documentation<7>,  Prev: Library<10>,  Up: Python 3 13 4 final

1.23.10.5 IDLE
..............

   - gh-112936(1): fix IDLE: no Shell menu item in single-process mode.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112936


File: python.info,  Node: Documentation<7>,  Next: Library<11>,  Prev: IDLE<5>,  Up: Python 3 13 4 final

1.23.10.6 Documentation
.......................

   - gh-107006(1): Move documentation and example code for *note
     threading.local: 1650. from its docstring to the official docs.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/107006


File: python.info,  Node: Library<11>,  Next: Core and Builtins<9>,  Prev: Documentation<7>,  Up: Python 3 13 4 final

1.23.10.7 Library
.................

   - gh-134908(1): Fix crash when iterating over lines in a text file on
     the *note free threaded: 15b3. build.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134908


File: python.info,  Node: Core and Builtins<9>,  Next: Library<12>,  Prev: Library<11>,  Up: Python 3 13 4 final

1.23.10.8 Core and Builtins
...........................

   - gh-127682(1): No longer call ‘__iter__’ twice in list
     comprehensions.  This brings the behavior of list comprehensions in
     line with other forms of iteration

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127682


File: python.info,  Node: Library<12>,  Next: Core and Builtins<10>,  Prev: Core and Builtins<9>,  Up: Python 3 13 4 final

1.23.10.9 Library
.................

   - gh-134381(1): Fix *note RuntimeError: 195. when using a not-started
     *note threading.Thread: 956. after calling *note os.fork(): 197.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134381


File: python.info,  Node: Core and Builtins<10>,  Next: C API<5>,  Prev: Library<12>,  Up: Python 3 13 4 final

1.23.10.10 Core and Builtins
............................

   - gh-128066(1): Fixes an edge case where PyREPL improperly threw an
     error when Python is invoked on a read only filesystem while trying
     to write history file entries.

   - gh-134100(2): Fix a use-after-free bug that occurs when an imported
     module isn’t in *note sys.modules: 1655. after its initial import.
     Patch by Nico-Posada.

   - gh-133703(3): Fix hashtable in dict can be bigger than intended in
     some situations.

   - gh-132869(4): Fix crash in the *note free threading: 15b3. build
     when accessing an object attribute that may be concurrently
     inserted or deleted.

   - gh-132762(5): *note fromkeys(): 1656. no longer loops forever when
     adding a small set of keys to a large base dict.  Patch by Angela
     Liss.

   - gh-133543(6): Fix a possible memory leak that could occur when
     directly accessing instance dictionaries (‘__dict__’) that later
     become part of a reference cycle.

   - gh-133516(7): Raise *note ValueError: 202. when constants ‘True’,
     ‘False’ or ‘None’ are used as an identifier after NFKC
     normalization.

   - gh-133441(8): Fix crash upon setting an attribute with a *note
     dict: 256. subclass.  Patch by Victor Stinner.

   - gh-132942(9): Fix two races in the type lookup cache.  This
     affected the free-threaded build and could cause crashes
     (apparently quite difficult to trigger).

   - gh-132713(10): Fix ‘repr(list)’ race condition: hold a strong
     reference to the item while calling ‘repr(item)’.  Patch by Victor
     Stinner.

   - gh-132747(11): Fix a crash when calling *note __get__(): 1537. of a
     *note method: 1657. with a *note None: 678. second argument.

   - gh-132542(12): Update *note Thread.native_id: a4c. after
     ‘fork(2)(13)’ to ensure accuracy.  Patch by Noam Cohen.

   - gh-124476(14): Fix decoding from the locale encoding in the C.UTF-8
     locale.

   - gh-131927(15): Compiler warnings originating from the same module
     and line number are now only emitted once, matching the behaviour
     of warnings emitted from user code.  This can also be configured
     with *note warnings: 112. filters.

   - gh-127682(16): No longer call ‘__iter__’ twice when creating and
     executing a generator expression.  Creating a generator expression
     from a non-interable will raise only when the generator expression
     is executed.  This brings the behavior of generator expressions in
     line with other generators.

   - gh-131878(17): Handle uncaught exceptions in the main input loop
     for the new REPL.

   - gh-131878(18): Fix support of unicode characters with two or more
     codepoints on Windows in the new REPL.

   - gh-130804(19): Fix support of unicode characters on Windows in the
     new REPL.

   - gh-130070(20): Fixed an assertion error for *note exec(): 17f.
     passed a string ‘source’ and a non-‘None’ ‘closure’.  Patch by
     Bartosz Sławecki.

   - gh-129958(21): Fix a bug that was allowing newlines inconsitently
     in format specifiers for single-quoted f-strings.  Patch by Pablo
     Galindo.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/128066

   (2) https://github.com/python/cpython/issues/134100

   (3) https://github.com/python/cpython/issues/133703

   (4) https://github.com/python/cpython/issues/132869

   (5) https://github.com/python/cpython/issues/132762

   (6) https://github.com/python/cpython/issues/133543

   (7) https://github.com/python/cpython/issues/133516

   (8) https://github.com/python/cpython/issues/133441

   (9) https://github.com/python/cpython/issues/132942

   (10) https://github.com/python/cpython/issues/132713

   (11) https://github.com/python/cpython/issues/132747

   (12) https://github.com/python/cpython/issues/132542

   (13) https://manpages.debian.org/fork(2)

   (14) https://github.com/python/cpython/issues/124476

   (15) https://github.com/python/cpython/issues/131927

   (16) https://github.com/python/cpython/issues/127682

   (17) https://github.com/python/cpython/issues/131878

   (18) https://github.com/python/cpython/issues/131878

   (19) https://github.com/python/cpython/issues/130804

   (20) https://github.com/python/cpython/issues/130070

   (21) https://github.com/python/cpython/issues/129958


File: python.info,  Node: C API<5>,  Next: Build<5>,  Prev: Core and Builtins<10>,  Up: Python 3 13 4 final

1.23.10.11 C API
................

   - gh-132909(1): Fix an overflow when handling the *note K: 1659.
     format in *note Py_BuildValue(): 8af.  Patch by Bénédikt Tran.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/132909


File: python.info,  Node: Build<5>,  Prev: C API<5>,  Up: Python 3 13 4 final

1.23.10.12 Build
................

   - gh-134923(1): Windows builds with profile-guided optimization
     enabled now use ‘/GENPROFILE’ and ‘/USEPROFILE’ instead of
     deprecated ‘/LTCG:’ options.

   - gh-133183(2): iOS compiler shims now include
     ‘IPHONEOS_DEPLOYMENT_TARGET’ in target triples, ensuring that SDK
     version minimums are honored.

   - gh-133167(3): Fix compilation process with ‘--enable-optimizations’
     and ‘--without-docstrings’.

   - gh-132649(4): The ‘PClayout’ script now allows passing
     ‘--include-tcltk’ on Windows ARM64.

   - gh-117088(5): AIX linker don’t support -h option, so avoid it
     through platform check

   - gh-132026(6): Fix use of undefined identifiers in platform triplet
     detection on MIPS Linux platforms.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/134923

   (2) https://github.com/python/cpython/issues/133183

   (3) https://github.com/python/cpython/issues/133167

   (4) https://github.com/python/cpython/issues/132649

   (5) https://github.com/python/cpython/issues/117088

   (6) https://github.com/python/cpython/issues/132026


File: python.info,  Node: Python 3 13 3 final,  Next: Python 3 13 2 final,  Prev: Python 3 13 4 final,  Up: Changelog

1.23.11 Python 3.13.3 final
---------------------------

'Release date: 2025-04-08'

* Menu:

* macOS: macOS<4>.
* Windows: Windows<7>.
* Tools/Demos: Tools/Demos<5>.
* Tests: Tests<8>.
* Security: Security<8>.
* Library: Library<13>.
* IDLE: IDLE<6>.
* Documentation: Documentation<8>.
* Core and Builtins: Core and Builtins<11>.
* Library: Library<14>.
* Core and Builtins: Core and Builtins<12>.
* C API: C API<6>.
* Build: Build<6>.


File: python.info,  Node: macOS<4>,  Next: Windows<7>,  Up: Python 3 13 3 final

1.23.11.1 macOS
...............

   - gh-124111(1): Update macOS installer to use Tcl/Tk 8.6.16.

   - gh-131423(2): Update macOS installer to use OpenSSL 3.0.16.  Patch
     by Bénédikt Tran.

   - gh-131025(3): Update macOS installer to ship with SQLite 3.49.1.

   - gh-91132(4): Update macOS installer to use ncurses 6.5.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124111

   (2) https://github.com/python/cpython/issues/131423

   (3) https://github.com/python/cpython/issues/131025

   (4) https://github.com/python/cpython/issues/91132


File: python.info,  Node: Windows<7>,  Next: Tools/Demos<5>,  Prev: macOS<4>,  Up: Python 3 13 3 final

1.23.11.2 Windows
.................

   - gh-131423(1): Update bundled version of OpenSSL to 3.0.16.  The new
     build also disables uplink support, which may be relevant to
     embedders but has no impact on normal use.

   - gh-131025(2): Update Windows installer to ship with SQLite 3.49.1.

   - gh-131020(3): pylauncher(4) correctly detects a BOM when searching
     for the shebang.  Fix by Chris Eibl.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131423

   (2) https://github.com/python/cpython/issues/131025

   (3) https://github.com/python/cpython/issues/131020

   (4) https://github.com/python/cpython/tree/3.13/PC/launcher2.c


File: python.info,  Node: Tools/Demos<5>,  Next: Tests<8>,  Prev: Windows<7>,  Up: Python 3 13 3 final

1.23.11.3 Tools/Demos
.....................

   - gh-131852(1): ‘msgfmt’ no longer adds the ‘POT-Creation-Date’ to
     generated ‘.mo’ files for consistency with GNU ‘msgfmt’.

   - gh-85012(2): Correctly reset ‘msgctxt’ when compiling messages in
     ‘msgfmt’.

   - gh-130025(3): The iOS testbed now correctly handles symlinks used
     as Python framework references.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131852

   (2) https://github.com/python/cpython/issues/85012

   (3) https://github.com/python/cpython/issues/130025


File: python.info,  Node: Tests<8>,  Next: Security<8>,  Prev: Tools/Demos<5>,  Up: Python 3 13 3 final

1.23.11.4 Tests
...............

   - gh-131050(1): ‘test_ssl.test_dh_params’ is skipped if the
     underlying TLS library does not support finite-field ephemeral
     Diffie-Hellman.

   - gh-129200(2): Multiple iOS testbed runners can now be started at
     the same time without introducing an ambiguity over simulator
     ownership.

   - gh-130292(3): The iOS testbed will now run successfully on a
     machine that has not previously run Xcode tests (such as CI
     configurations).

   - gh-130293(4): The tests of terminal colorization are no longer
     sensitive to the value of the ‘TERM’ variable in the testing
     environment.

   - gh-126332(5): Add unit tests for pyrepl.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131050

   (2) https://github.com/python/cpython/issues/129200

   (3) https://github.com/python/cpython/issues/130292

   (4) https://github.com/python/cpython/issues/130293

   (5) https://github.com/python/cpython/issues/126332


File: python.info,  Node: Security<8>,  Next: Library<13>,  Prev: Tests<8>,  Up: Python 3 13 3 final

1.23.11.5 Security
..................

   - gh-131809(1): Update bundled libexpat to 2.7.1

   - gh-131261(2): Upgrade to libexpat 2.7.0

   - gh-127371(3): Avoid unbounded buffering for
     ‘tempfile.SpooledTemporaryFile.writelines()’.  Previously, disk
     spillover was only checked after the lines iterator had been
     exhausted.  This is now done after each line is written.

   - gh-121284(4): Fix bug in the folding of rfc2047 encoded-words when
     flattening an email message using a modern email policy.
     Previously when an encoded-word was too long for a line, it would
     be decoded, split across lines, and re-encoded.  But commas and
     other special characters in the original text could be left
     unencoded and unquoted.  This could theoretically be used to spoof
     header lines using a carefully constructed encoded-word if the
     resulting rendered email was transmitted or re-parsed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131809

   (2) https://github.com/python/cpython/issues/131261

   (3) https://github.com/python/cpython/issues/127371

   (4) https://github.com/python/cpython/issues/121284


File: python.info,  Node: Library<13>,  Next: IDLE<6>,  Prev: Security<8>,  Up: Python 3 13 3 final

1.23.11.6 Library
.................

   - gh-132174(1): Fix function name in error message of
     ‘_interpreters.run_string’.

   - gh-132171(2): Fix crash of ‘_interpreters.run_string’ on string
     subclasses.

   - gh-129204(3): Introduce new ‘_PYTHON_SUBPROCESS_USE_POSIX_SPAWN’
     environment variable knob in *note subprocess: d6. to control the
     use of *note os.posix_spawn(): 220.

   - gh-132159(4): Do not shadow user arguments in generated ‘__new__()’
     by decorator *note warnings.deprecated: 160.  Patch by Xuehai Pan.

   - gh-132075(5): Fix possible use of *note socket: cc. address
     structures with uninitialized members.  Now all structure members
     are initialized with zeroes by default.

   - gh-132002(6): Fix crash when deallocating *note
     contextvars.ContextVar: 1662. with weird unahashable string names.

   - gh-131668(7): *note socket: cc.: Fix code parsing AF_BLUETOOTH
     socket addresses.

   - gh-131492(8): Fix a resource leak when constructing a *note
     gzip.GzipFile: 41d. with a filename fails, for example when passing
     an invalid ‘compresslevel’.

   - gh-131325(9): Fix sendfile fallback implementation to drain data
     after writing to transport in *note asyncio: a.

   - gh-129843(10): Fix incorrect argument passing in *note
     warnings.warn_explicit(): d28.

   - gh-131204(11): Use monospace font from System Font Stack for
     cross-platform support in *note difflib.HtmlDiff: 1663.

   - gh-130940(12): The ‘PyConfig.use_system_logger’ attribute,
     introduced in Python 3.13.2, has been removed.  The introduction of
     this attribute inadvertently introduced an ABI breakage on macOS
     and iOS. The use of the system logger is now enabled by default on
     iOS, and disabled by default on macOS.

   - gh-131045(13): Fix issue with ‘__contains__’, values, and
     pseudo-members for *note enum.Flag: 626.

   - gh-130959(14): Fix pure-Python implementation of *note
     datetime.time.fromisoformat(): 619. to reject times with spaces in
     fractional part (for example, ‘12:34:56.400 +02:00’), matching the
     C implementation.  Patch by Michał Gorny.

   - gh-130637(15): Add validation for numeric response data in
     poplib.POP3.stat() method

   - gh-130461(16): Remove ‘.. index::’ directives from the *note uuid:
     110. module documentation.  These directives previously created
     entries in the general index for *note getnode(): bc5. as well as
     the *note uuid1(): bc6, *note uuid3(): 1664, *note uuid4(): 1665,
     and *note uuid5(): 1666. constructor functions.

   - gh-130379(17): The zipapp module now calculates the list of files
     to be added to the archive before creating the archive.  This
     avoids accidentally including the target when it is being created
     in the source directory.

   - gh-130285(18): Fix corner case for *note random.sample(): 749.
     allowing the 'counts' parameter to specify an empty population.  So
     now, ‘sample([], 0, counts=[])’ and ‘sample('abc', k=0, counts=[0,
     0, 0])’ both give the same result as ‘sample([], 0)’.

   - gh-130250(19): Fix regression in ‘traceback.print_last()’.

   - gh-130230(20): Fix crash in *note pow(): 9dd. with only *note
     Decimal: 29d. third argument.

   - gh-118761(21): Reverts a change in the previous release attempting
     to make some stdlib imports used within the *note subprocess: d6.
     module lazy as this was causing errors during ‘__del__’ finalizers
     calling methods such as ‘terminate’, or ‘kill’, or ‘send_signal’.

   - gh-130164(22): Fixed failure to raise *note TypeError: 2c3. in
     *note inspect.Signature.bind(): 1667. for positional-only arguments
     provided by keyword when a variadic keyword argument (e.g.
     ‘**kwargs’) is present.

   - gh-130151(23): Fix reference leaks in ‘_hashlib.hmac_new()’ and
     ‘_hashlib.hmac_digest()’.  Patch by Bénédikt Tran.

   - gh-130145(24): Fix ‘asyncio.AbstractEventloop.run_forever()’ when
     another loop is already running.

   - gh-129726(25): Fix *note gzip.GzipFile: 41d. raising an unraisable
     exception during garbage collection when referring to a temporary
     object by breaking the reference loop with *note weakref: 114.

   - gh-127750(26): Remove broken *note
     functools.singledispatchmethod(): 9fb. caching introduced in
     gh-85160(27).

   - gh-129583(28): Update bundled pip to 25.0.1

   - gh-97850(29): Update the deprecation warning of *note
     importlib.abc.Loader.load_module(): 870.

   - gh-129646(30): Update the locale alias mapping in the *note locale:
     86. module to match the latest X Org locale alias mapping and
     support new locales in Glibc 2.41.

   - gh-129603(31): Fix bugs where *note sqlite3.Row: ea5. objects could
     segfault if their inherited *note description: 1668. was set to
     ‘None’.  Patch by Erlend Aasland.

   - gh-128231(32): Execution of multiple statements in the new REPL now
     stops immediately upon the first exception encountered.  Patch by
     Bartosz Sławecki.

   - gh-117779(33): Fix reading duplicated entries in *note zipfile:
     131. by name.  Reading duplicated entries (except the last one) by
     ‘ZipInfo’ now emits a warning instead of raising an exception.

   - gh-128772(34): Fix *note pydoc: b5. for methods with the
     ‘__module__’ attribute equal to ‘None’.

   - gh-92897(35): Scheduled the deprecation of the ‘check_home’
     argument of *note sysconfig.is_python_build(): 2dd. to Python 3.15.

   - gh-128657(36): Fix possible extra reference when using objects
     returned by *note hashlib.sha256(): 1669. under *note free
     threading: 15b3.

   - gh-128703(37): Fix *note mimetypes.guess_type(): 208. to use
     default mapping for empty ‘Content-Type’ in registry.

   - gh-128308(38): Support the 'name' keyword argument for eager tasks
     in *note asyncio.loop.create_task(): 1c0, *note
     asyncio.create_task(): 1bf. and *note
     asyncio.TaskGroup.create_task(): 1bc, by passing on all 'kwargs' to
     the task factory set by *note asyncio.loop.set_task_factory(): df4.

   - gh-128388(39): Fix ‘PyREPL’ on Windows to support more keybindings,
     like the ‘Control’-‘←’ and ‘Control’-‘→’ word-skipping keybindings
     and those with meta (i.e.  ‘Alt’), e.g.  ‘Alt’-‘d’ to ‘kill-word’
     or ‘Alt’-‘Backspace’ ‘backward-kill-word’.

   - gh-126037(40): *note xml.etree.ElementTree: 125.: Fix a crash in
     *note Element.find: 166a, *note Element.findtext: 166b. and *note
     Element.findall: 166c. when the tag to find implements an *note
     __eq__(): b13. method mutating the element being queried.  Patch by
     Bénédikt Tran.

   - gh-127712(41): Fix handling of the ‘secure’ argument of *note
     logging.handlers.SMTPHandler: 166d.

   - gh-126033(42): *note xml.etree.ElementTree: 125.: Fix a crash in
     *note Element.remove: 166e. when the element is concurrently
     mutated.  Patch by Bénédikt Tran.

   - gh-118201(43): Fixed intermittent failures of *note os.confstr:
     166f, *note os.pathconf: 113f. and *note os.sysconf: 1670. on iOS
     and Android.

   - gh-124927(44): Non-printing characters are now properly handled in
     the new REPL.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/132174

   (2) https://github.com/python/cpython/issues/132171

   (3) https://github.com/python/cpython/issues/129204

   (4) https://github.com/python/cpython/issues/132159

   (5) https://github.com/python/cpython/issues/132075

   (6) https://github.com/python/cpython/issues/132002

   (7) https://github.com/python/cpython/issues/131668

   (8) https://github.com/python/cpython/issues/131492

   (9) https://github.com/python/cpython/issues/131325

   (10) https://github.com/python/cpython/issues/129843

   (11) https://github.com/python/cpython/issues/131204

   (12) https://github.com/python/cpython/issues/130940

   (13) https://github.com/python/cpython/issues/131045

   (14) https://github.com/python/cpython/issues/130959

   (15) https://github.com/python/cpython/issues/130637

   (16) https://github.com/python/cpython/issues/130461

   (17) https://github.com/python/cpython/issues/130379

   (18) https://github.com/python/cpython/issues/130285

   (19) https://github.com/python/cpython/issues/130250

   (20) https://github.com/python/cpython/issues/130230

   (21) https://github.com/python/cpython/issues/118761

   (22) https://github.com/python/cpython/issues/130164

   (23) https://github.com/python/cpython/issues/130151

   (24) https://github.com/python/cpython/issues/130145

   (25) https://github.com/python/cpython/issues/129726

   (26) https://github.com/python/cpython/issues/127750

   (27) https://github.com/python/cpython/issues/85160

   (28) https://github.com/python/cpython/issues/129583

   (29) https://github.com/python/cpython/issues/97850

   (30) https://github.com/python/cpython/issues/129646

   (31) https://github.com/python/cpython/issues/129603

   (32) https://github.com/python/cpython/issues/128231

   (33) https://github.com/python/cpython/issues/117779

   (34) https://github.com/python/cpython/issues/128772

   (35) https://github.com/python/cpython/issues/92897

   (36) https://github.com/python/cpython/issues/128657

   (37) https://github.com/python/cpython/issues/128703

   (38) https://github.com/python/cpython/issues/128308

   (39) https://github.com/python/cpython/issues/128388

   (40) https://github.com/python/cpython/issues/126037

   (41) https://github.com/python/cpython/issues/127712

   (42) https://github.com/python/cpython/issues/126033

   (43) https://github.com/python/cpython/issues/118201

   (44) https://github.com/python/cpython/issues/124927


File: python.info,  Node: IDLE<6>,  Next: Documentation<8>,  Prev: Library<13>,  Up: Python 3 13 3 final

1.23.11.7 IDLE
..............

   - gh-129873(1): Simplify displaying the IDLE doc by only copying the
     text section of idle.html to idlelib/help.html.  Patch by Stan
     Ulbrych.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129873


File: python.info,  Node: Documentation<8>,  Next: Core and Builtins<11>,  Prev: IDLE<6>,  Up: Python 3 13 3 final

1.23.11.8 Documentation
.......................

   - gh-131417(1): Mention *note asyncio.Future: bec. and *note
     asyncio.Task: 1be. in generic classes list.

   - gh-125722(2): Require Sphinx 8.2.0 or later to build the Python
     documentation.  Patch by Adam Turner.

   - gh-129712(3): The wheel tags supported by each macOS universal SDK
     option are now documented.

   - gh-46236(4): C API: Document *note PyUnicode_RSplit(): 1673, *note
     PyUnicode_Partition(): 1674. and *note PyUnicode_RPartition():
     1675.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131417

   (2) https://github.com/python/cpython/issues/125722

   (3) https://github.com/python/cpython/issues/129712

   (4) https://github.com/python/cpython/issues/46236


File: python.info,  Node: Core and Builtins<11>,  Next: Library<14>,  Prev: Documentation<8>,  Up: Python 3 13 3 final

1.23.11.9 Core and Builtins
...........................

   - gh-132011(1): Fix crash when calling ‘list.append()’ as an unbound
     method.

   - gh-131998(2): Fix a crash when using an unbound method *note
     descriptor: 1677. object in a function where a bound method
     descriptor was used.

   - gh-131988(3): Fix a performance regression that caused scaling
     bottlenecks in the free threaded build in 3.13.1 and 3.13.2.

   - gh-131719(4): Fix missing NULL check in ‘_PyMem_FreeDelayed’ in
     *note free-threaded: 15b3. build.

   - gh-131670(5): Fix *note anext(): 7da. failing on sync *note
     __anext__(): 1678. raising an exception.

   - gh-131141(6): Fix data race in *note sys.monitoring: da.
     instrumentation while registering callback.

   - gh-130932(7): Fix incorrect exception handling in
     ‘_PyModule_IsPossiblyShadowing’

   - gh-130851(8): Fix a crash in the *note free threading: 15b3. build
     when constructing a *note code: 1a. object with *note co_consts:
     1679. that contains instances of types that are not otherwise
     generated by the bytecode compiler.

   - gh-130794(9): Fix memory leak in the *note free threaded: 15b3.
     build when resizing a shared list or dictionary from multiple
     short-lived threads.

   - gh-130775(10): Do not crash on negative ‘column’ and ‘end_column’
     in *note ast: 8. locations.

   - gh-130382(11): Fix ‘PyRefTracer_DESTROY’ not being sent from
     ‘Python/ceval.c’ ‘Py_DECREF()’.

   - gh-130618(12): Fix a bug that was causing ‘UnicodeDecodeError’ or
     ‘SystemError’ to be raised when using f-strings with ‘lambda’
     expressions with non-ASCII characters.  Patch by Pablo Galindo

   - gh-130163(13): Fix possible crashes related to concurrent change
     and use of the *note sys: d9. module attributes.

   - gh-88887(14): Fixing multiprocessing Resource Tracker process
     leaking, usually observed when running Python as PID 1.

   - gh-130115(15): Fix an issue with thread identifiers being
     sign-extended on some platforms.

   - gh-128396(16): Fix a crash that occurs when calling *note locals():
     141. inside an inline comprehension that uses the same local
     variable as the outer frame scope where the variable is a free or
     cell var.

   - gh-116042(17): Fix location for SyntaxErrors of invalid escapes in
     the tokenizer.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/132011

   (2) https://github.com/python/cpython/issues/131998

   (3) https://github.com/python/cpython/issues/131988

   (4) https://github.com/python/cpython/issues/131719

   (5) https://github.com/python/cpython/issues/131670

   (6) https://github.com/python/cpython/issues/131141

   (7) https://github.com/python/cpython/issues/130932

   (8) https://github.com/python/cpython/issues/130851

   (9) https://github.com/python/cpython/issues/130794

   (10) https://github.com/python/cpython/issues/130775

   (11) https://github.com/python/cpython/issues/130382

   (12) https://github.com/python/cpython/issues/130618

   (13) https://github.com/python/cpython/issues/130163

   (14) https://github.com/python/cpython/issues/88887

   (15) https://github.com/python/cpython/issues/130115

   (16) https://github.com/python/cpython/issues/128396

   (17) https://github.com/python/cpython/issues/116042


File: python.info,  Node: Library<14>,  Next: Core and Builtins<12>,  Prev: Core and Builtins<11>,  Up: Python 3 13 3 final

1.23.11.10 Library
..................

   - gh-129983(1): Fix data race in compile_template in ‘sre.c’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129983


File: python.info,  Node: Core and Builtins<12>,  Next: C API<6>,  Prev: Library<14>,  Up: Python 3 13 3 final

1.23.11.11 Core and Builtins
............................

   - gh-129967(1): Fix a race condition in the *note free threading:
     15b3. build when ‘repr(set)’ is called concurrently with
     ‘set.clear()’.

   - gh-129900(2): Fix return codes inside *note SystemExit: d69. not
     getting returned by the REPL.

   - gh-129732(3): Fixed a race in ‘_Py_qsbr_reserve’ in the free
     threading build.

   - gh-129643(4): Fix thread safety of *note PyList_Insert(): 167c. in
     free-threading builds.

   - gh-129668(5): Fix race condition when raising *note MemoryError:
     15ab. in the free threaded build.

   - gh-129643(6): Fix thread safety of *note PyList_SetItem(): 167d. in
     free-threading builds.  Patch by Kumar Aditya.

   - gh-128714(7): Fix the potential races in get/set dunder methods
     ‘__annotations__’, ‘__annotate__’ and ‘__type_params__’ for
     function object, and add related tests.

   - gh-128632(8): Disallow ‘__classdict__’ as the name of a type
     parameter.  Using this name would previously crash the interpreter
     in some circumstances.

   - gh-127953(9): The time to handle a ‘LINE’ event in sys.monitoring
     (and sys.settrace) is now independent of the number of lines in the
     code object.

   - gh-125331(10): ‘from __future__ import barry_as_FLUFL’ now works in
     more contexts, including when it is used in files, with the ‘-c’
     flag, and in the REPL when there are multiple statements on the
     same line.  Previously, it worked only on subsequent lines in the
     REPL, and when the appropriate flags were passed directly to *note
     compile(): 192.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129967

   (2) https://github.com/python/cpython/issues/129900

   (3) https://github.com/python/cpython/issues/129732

   (4) https://github.com/python/cpython/issues/129643

   (5) https://github.com/python/cpython/issues/129668

   (6) https://github.com/python/cpython/issues/129643

   (7) https://github.com/python/cpython/issues/128714

   (8) https://github.com/python/cpython/issues/128632

   (9) https://github.com/python/cpython/issues/127953

   (10) https://github.com/python/cpython/issues/125331


File: python.info,  Node: C API<6>,  Next: Build<6>,  Prev: Core and Builtins<12>,  Up: Python 3 13 3 final

1.23.11.12 C API
................

   - gh-131740(1): Update PyUnstable_GC_VisitObjects to traverse perm
     gen.

   - gh-129533(2): Update *note PyGC_Enable(): 8ab, *note
     PyGC_Disable(): 8ac, *note PyGC_IsEnabled(): 8ad. to use atomic
     operation for thread-safety at free-threading build.  Patch by
     Donghee Na.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131740

   (2) https://github.com/python/cpython/issues/129533


File: python.info,  Node: Build<6>,  Prev: C API<6>,  Up: Python 3 13 3 final

1.23.11.13 Build
................

   - gh-131865(1): The DTrace build now properly passes the ‘CC’ and
     ‘CFLAGS’ variables to the ‘dtrace’ command when utilizing SystemTap
     on Linux.

   - gh-131675(2): Fix mimalloc library builds for 32-bit ARM targets.

   - gh-130673(3): Fix potential ‘KeyError’ when handling object
     sections during JIT building process.

   - gh-130740(4): Ensure that ‘Python.h’ is included before ‘stdbool.h’
     unless ‘pyconfig.h’ is included before or in some platform-specific
     contexts.

   - gh-129838(5): Don’t redefine ‘_Py_NO_SANITIZE_UNDEFINED’ when
     compiling with a recent GCC version and undefined sanitizer
     enabled.

   - gh-129660(6): Drop ‘test_embed’ from PGO training, whose
     contribution in recent versions is considered to be ignorable.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/131865

   (2) https://github.com/python/cpython/issues/131675

   (3) https://github.com/python/cpython/issues/130673

   (4) https://github.com/python/cpython/issues/130740

   (5) https://github.com/python/cpython/issues/129838

   (6) https://github.com/python/cpython/issues/129660


File: python.info,  Node: Python 3 13 2 final,  Next: Python 3 13 1 final,  Prev: Python 3 13 3 final,  Up: Changelog

1.23.12 Python 3.13.2 final
---------------------------

'Release date: 2025-02-04'

* Menu:

* macOS: macOS<5>.
* Windows: Windows<8>.
* Tools/Demos: Tools/Demos<6>.
* Tests: Tests<9>.
* Security: Security<9>.
* Library: Library<15>.
* Documentation: Documentation<9>.
* Library: Library<16>.
* Core and Builtins: Core and Builtins<13>.
* C API: C API<7>.
* Build: Build<7>.


File: python.info,  Node: macOS<5>,  Next: Windows<8>,  Up: Python 3 13 2 final

1.23.12.1 macOS
...............

   - gh-127592(1): Usage of the unified Apple System Log APIs was
     disabled when the minimum macOS version is earlier than 10.12.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127592


File: python.info,  Node: Windows<8>,  Next: Tools/Demos<6>,  Prev: macOS<5>,  Up: Python 3 13 2 final

1.23.12.2 Windows
.................

   - gh-127353(1): Allow to force color output on Windows using
     environment variables.  Patch by Andrey Efremov.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127353


File: python.info,  Node: Tools/Demos<6>,  Next: Tests<9>,  Prev: Windows<8>,  Up: Python 3 13 2 final

1.23.12.3 Tools/Demos
.....................

   - gh-129248(1): The iOS test runner now strips the log prefix from
     each line output by the test suite.

   - gh-128152(2): Fix a bug where Argument Clinic’s C pre-processor
     parser tried to parse pre-processor directives inside C comments.
     Patch by Erlend Aasland.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129248

   (2) https://github.com/python/cpython/issues/128152


File: python.info,  Node: Tests<9>,  Next: Security<9>,  Prev: Tools/Demos<6>,  Up: Python 3 13 2 final

1.23.12.4 Tests
...............

   - gh-127906(1): Test the limited C API in test_cppext.  Patch by
     Victor Stinner.

   - gh-127637(2): Add tests for the *note dis: 38. command-line
     interface.  Patch by Bénédikt Tran.

   - gh-126925(3): iOS test results are now streamed during test
     execution, and the deprecated xcresulttool is no longer used.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127906

   (2) https://github.com/python/cpython/issues/127637

   (3) https://github.com/python/cpython/issues/126925


File: python.info,  Node: Security<9>,  Next: Library<15>,  Prev: Tests<9>,  Up: Python 3 13 2 final

1.23.12.5 Security
..................

   - gh-105704(1): When using *note urllib.parse.urlsplit(): d67. and
     *note urllib.parse.urlparse(): 30d. host parsing would not reject
     domain names containing square brackets (‘[’ and ‘]’).  Square
     brackets are only valid for IPv6 and IPvFuture hosts according to
     RFC 3986 Section 3.2.2(2).

   - gh-127655(3): Fixed the
     ‘asyncio.selector_events._SelectorSocketTransport’ transport not
     pausing writes for the protocol when the buffer reaches the high
     water mark when using *note asyncio.WriteTransport.writelines():
     1600.

   - gh-126108(4): Fix a possible ‘NULL’ pointer dereference in
     ‘PySys_AddWarnOptionUnicode()’.

   - gh-80222(5): Fix bug in the folding of quoted strings when
     flattening an email message using a modern email policy.
     Previously when a quoted string was folded so that it spanned more
     than one line, the surrounding quotes and internal escapes would be
     omitted.  This could theoretically be used to spoof header lines
     using a carefully constructed quoted string if the resulting
     rendered email was transmitted or re-parsed.

   - gh-119511(6): Fix a potential denial of service in the *note
     imaplib: 74. module.  When connecting to a malicious server, it
     could cause an arbitrary amount of memory to be allocated.  On many
     systems this is harmless as unused virtual memory is only a
     mapping, but if this hit a virtual address size limit it could lead
     to a *note MemoryError: 15ab. or other process crash.  On unusual
     systems or builds where all allocated memory is touched and backed
     by actual ram or storage it could’ve consumed resources doing so
     until similarly crashing.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105704

   (2) https://www.rfc-editor.org/rfc/rfc3986#section-3.2.2

   (3) https://github.com/python/cpython/issues/127655

   (4) https://github.com/python/cpython/issues/126108

   (5) https://github.com/python/cpython/issues/80222

   (6) https://github.com/python/cpython/issues/119511


File: python.info,  Node: Library<15>,  Next: Documentation<9>,  Prev: Security<9>,  Up: Python 3 13 2 final

1.23.12.6 Library
.................

   - gh-129502(1): Unlikely errors in preparing arguments for *note
     ctypes: 2a. callback are now handled in the same way as errors
     raised in the callback of in converting the result of the callback
     – using *note sys.unraisablehook(): 1f7. instead of *note
     sys.excepthook(): 811. and not setting *note sys.last_exc: 4c1. and
     other variables.

   - gh-129403(2): Corrected *note ValueError: 202. message for *note
     asyncio.Barrier: 604. and *note threading.Barrier: 1228.

   - gh-129409(3): Fix an integer overflow in the *note csv: 29. module
     when writing a data field larger than 2GB.

   - gh-118761(4): Improve import time of *note subprocess: d6. by lazy
     importing ‘locale’ and ‘signal’.  Patch by Taneli Hukkinen.

   - gh-129346(5): In *note sqlite3: cf, handle out-of-memory when
     creating user-defined SQL functions.

   - gh-129061(6): Fix FORCE_COLOR and NO_COLOR when empty strings.
     Patch by Hugo van Kemenade.

   - gh-128550(7): Removed an incorrect optimization relating to eager
     tasks in *note asyncio.TaskGroup: 1b5. that resulted in
     cancellations being missed.

   - gh-128991(8): Release the enter frame reference within *note bdb:
     f. callback

   - gh-128978(9): Fix a *note NameError: 442. in
     ‘sysconfig.expand_makefile_vars()’.  Patch by Bénédikt Tran.

   - gh-128961(10): Fix a crash when setting state on an exhausted *note
     array.array: 1a0. iterator.

   - gh-128894(11): Fix
     ‘traceback.TracebackException._format_syntax_error’ not to fail on
     exceptions with custom metadata.

   - gh-128916(12): Do not attempt to set ‘SO_REUSEPORT’ on sockets of
     address families other than ‘AF_INET’ and ‘AF_INET6’, as it is
     meaningless with these address families, and the call with fail
     with Linux kernel 6.12.9 and newer.

   - gh-128679(13): Fix *note tracemalloc.stop(): 1687. race condition.
     Fix *note tracemalloc: ff. to support calling ‘tracemalloc.stop()’
     in one thread, while another thread is tracing memory allocations.
     Patch by Victor Stinner.

   - gh-128636(14): Fix PyREPL failure when *note os.environ: 11fe. is
     overwritten with an invalid value.

   - gh-128562(15): Fix possible conflicts in generated *note tkinter:
     f0. widget names if the widget class name ends with a digit.

   - gh-128498(16): Default to stdout isatty for color detection instead
     of stderr.  Patch by Hugo van Kemenade.

   - gh-128552(17): Fix cyclic garbage introduced by *note
     asyncio.loop.create_task(): 1c0. and *note
     asyncio.TaskGroup.create_task(): 1bc. holding a reference to the
     created task if it is eager.

   - gh-128479(18): Fix ‘asyncio.staggered.staggered_race()’ leaking
     tasks and issuing an unhandled exception.

   - gh-128400(19): Fix crash when using *note
     faulthandler.dump_traceback(): e30. while other threads are active
     on the *note free threaded: 15b3. build.

   - gh-88834(20): Unify the instance check for *note typing.Union: 63e.
     and *note types.UnionType: 63d.: ‘Union’ now uses the instance
     checks against its parameters instead of the subclass checks.

   - gh-128302(21): Fix
     ‘xml.dom.xmlbuilder.DOMEntityResolver.resolveEntity()’, which was
     broken by the Python 3.0 transition.

   - gh-128302(22): Allow ‘xml.dom.xmlbuilder.DOMParser.parse()’ to
     correctly handle ‘xml.dom.xmlbuilder.DOMInputSource’ instances that
     only have a ‘systemId’ attribute set.

   - gh-112064(23): Fix incorrect handling of negative read sizes in
     *note HTTPResponse.read: 1688.  Patch by Yury Manushkin.

   - gh-58956(24): Fixed a frame reference leak in *note bdb: f.

   - gh-128131(25): Completely support random access of uncompressed
     unencrypted read-only zip files obtained by *note ZipFile.open:
     41e.

   - gh-112328(26): *note enum.EnumDict: 1e4. can now be used without
     resorting to private API.

   - gh-127975(27): Avoid reusing quote types in *note ast.unparse():
     8ee. if not needed.

   - gh-128062(28): Revert the font of *note turtledemo: 102.’s menu bar
     to its default value and display the shortcut keys in the correct
     position.

   - gh-128014(29): Fix resetting the default window icon by passing
     ‘default=''’ to the *note tkinter: f0. method ‘wm_iconbitmap()’.

   - gh-115514(30): Fix exceptions and incomplete writes after
     ‘asyncio._SelectorTransport’ is closed before writes are completed.

   - gh-41872(31): Fix quick extraction of module docstrings from a file
     in *note pydoc: b5.  It now supports docstrings with single quotes,
     escape sequences, raw string literals, and other Python syntax.

   - gh-127060(32): Set TERM environment variable to “dumb” to disable
     traceback colors in IDLE, since IDLE doesn’t understand ANSI escape
     sequences.  Patch by Victor Stinner.

   - gh-126742(33): Fix support of localized error messages reported by
     ‘dlerror(3)(34)’ and ‘gdbm_strerror(35)’ in *note ctypes: 2a. and
     *note dbm.gnu: 33. functions respectively.  Patch by Bénédikt Tran.

   - gh-127873(36): When ‘-E’ is set, only ignore ‘PYTHON_COLORS’ and
     not ‘FORCE_COLOR’/‘NO_COLOR’/‘TERM’ when colourising output.  Patch
     by Hugo van Kemenade.

   - gh-127870(37): Detect recursive calls in ctypes ‘_as_parameter_’
     handling.  Patch by Victor Stinner.

   - gh-127847(38): Fix the position when doing interleaved seeks and
     reads in uncompressed, unencrypted zip files returned by *note
     zipfile.ZipFile.open(): 41e.

   - gh-127732(39): The *note platform: aa. module now correctly detects
     Windows Server 2025.

   - gh-126821(40): macOS and iOS apps can now choose to redirect stdout
     and stderr to the system log during interpreter configuration.

   - gh-93312(41): Include ‘<sys/pidfd.h>’ to get ‘os.PIDFD_NONBLOCK’
     constant.  Patch by Victor Stinner.

   - gh-83662(42): Add missing ‘__class_getitem__’ method to the Python
     implementation of *note functools.partial(): 417, to make it
     compatible with the C version.  This is mainly relevant for
     alternative Python implementations like PyPy and GraalPy, because
     CPython will usually use the C-implementation of that function.

   - gh-127586(43): *note multiprocessing.pool.Pool: fa4. now properly
     restores blocked signal handlers of the parent thread when creating
     processes via either 'spawn' or 'forkserver'.

   - gh-98188(44): Fix an issue in *note
     email.message.Message.get_payload(): 1212. where data cannot be
     decoded if the Content Transfer Encoding mechanism contains
     trailing whitespaces or additional junk text.  Patch by Hui Liu.

   - gh-127257(45): In *note ssl: d0, system call failures that OpenSSL
     reports using ‘ERR_LIB_SYS’ are now raised as *note OSError: 41a.

   - gh-127096(46): Do not recreate unnamed section on every read in
     *note configparser.ConfigParser: 1c8.  Patch by Andrey Efremov.

   - gh-127196(47): Fix crash when dict with keys in invalid encoding
     were passed to several functions in ‘_interpreters’ module.

   - gh-126775(48): Make *note linecache.checkcache(): 1689. thread safe
     and GC re-entrancy safe.

   - gh-126332(49): Fix _pyrepl crash when entering a double CTRL-Z on
     an overflowing line.

   - gh-126225(50): *note getopt: 61. and *note optparse: a0. are no
     longer marked as deprecated.  There are legitimate reasons to use
     one of these modules in preference to *note argparse: 6, and none
     of these modules are at risk of being removed from the standard
     library.  Of the three, ‘argparse’ remains the recommended default
     choice, 'unless' one of the concerns noted at the top of the
     ‘optparse’ module documentation applies.

   - gh-125553(51): Fix round-trip invariance for backslash
     continuations in *note tokenize.untokenize(): 168a.

   - gh-123987(52): Fixed issue in NamespaceReader where a non-path item
     in a namespace path, such as a sentinel added by an editable
     installer, would break resource loading.

   - gh-123401(53): The *note http.cookies: 71. module now supports
     parsing obsolete RFC 850(54) date formats, in accordance with RFC
     9110(55) requirements.  Patch by Nano Zheng.

   - gh-122431(56): *note readline.append_history_file(): e85. now
     raises a *note ValueError: 202. when given a negative value.

   - gh-119257(57): Show tab completions menu below the current line,
     which results in less janky behaviour, and fixes a cursor movement
     bug.  Patch by Daniel Hollas

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129502

   (2) https://github.com/python/cpython/issues/129403

   (3) https://github.com/python/cpython/issues/129409

   (4) https://github.com/python/cpython/issues/118761

   (5) https://github.com/python/cpython/issues/129346

   (6) https://github.com/python/cpython/issues/129061

   (7) https://github.com/python/cpython/issues/128550

   (8) https://github.com/python/cpython/issues/128991

   (9) https://github.com/python/cpython/issues/128978

   (10) https://github.com/python/cpython/issues/128961

   (11) https://github.com/python/cpython/issues/128894

   (12) https://github.com/python/cpython/issues/128916

   (13) https://github.com/python/cpython/issues/128679

   (14) https://github.com/python/cpython/issues/128636

   (15) https://github.com/python/cpython/issues/128562

   (16) https://github.com/python/cpython/issues/128498

   (17) https://github.com/python/cpython/issues/128552

   (18) https://github.com/python/cpython/issues/128479

   (19) https://github.com/python/cpython/issues/128400

   (20) https://github.com/python/cpython/issues/88834

   (21) https://github.com/python/cpython/issues/128302

   (22) https://github.com/python/cpython/issues/128302

   (23) https://github.com/python/cpython/issues/112064

   (24) https://github.com/python/cpython/issues/58956

   (25) https://github.com/python/cpython/issues/128131

   (26) https://github.com/python/cpython/issues/112328

   (27) https://github.com/python/cpython/issues/127975

   (28) https://github.com/python/cpython/issues/128062

   (29) https://github.com/python/cpython/issues/128014

   (30) https://github.com/python/cpython/issues/115514

   (31) https://github.com/python/cpython/issues/41872

   (32) https://github.com/python/cpython/issues/127060

   (33) https://github.com/python/cpython/issues/126742

   (34) https://manpages.debian.org/dlerror(3)

   (35) https://manpages.debian.org/gdbm(3)

   (36) https://github.com/python/cpython/issues/127873

   (37) https://github.com/python/cpython/issues/127870

   (38) https://github.com/python/cpython/issues/127847

   (39) https://github.com/python/cpython/issues/127732

   (40) https://github.com/python/cpython/issues/126821

   (41) https://github.com/python/cpython/issues/93312

   (42) https://github.com/python/cpython/issues/83662

   (43) https://github.com/python/cpython/issues/127586

   (44) https://github.com/python/cpython/issues/98188

   (45) https://github.com/python/cpython/issues/127257

   (46) https://github.com/python/cpython/issues/127096

   (47) https://github.com/python/cpython/issues/127196

   (48) https://github.com/python/cpython/issues/126775

   (49) https://github.com/python/cpython/issues/126332

   (50) https://github.com/python/cpython/issues/126225

   (51) https://github.com/python/cpython/issues/125553

   (52) https://github.com/python/cpython/issues/123987

   (53) https://github.com/python/cpython/issues/123401

   (54) https://datatracker.ietf.org/doc/html/rfc850.html

   (55) https://datatracker.ietf.org/doc/html/rfc9110.html

   (56) https://github.com/python/cpython/issues/122431

   (57) https://github.com/python/cpython/issues/119257


File: python.info,  Node: Documentation<9>,  Next: Library<16>,  Prev: Library<15>,  Up: Python 3 13 2 final

1.23.12.7 Documentation
.......................

   - gh-125722(1): Require Sphinx 8.1.3 or later to build the Python
     documentation.  Patch by Adam Turner.

   - gh-67206(2): Document that *note string.printable: 168c. is not
     printable in the POSIX sense.  In particular, *note
     string.printable.isprintable(): e08. returns *note False: b4f.
     Patch by Bénédikt Tran.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/125722

   (2) https://github.com/python/cpython/issues/67206


File: python.info,  Node: Library<16>,  Next: Core and Builtins<13>,  Prev: Documentation<9>,  Up: Python 3 13 2 final

1.23.12.8 Library
.................

   - gh-129345(1): Fix null pointer dereference in *note
     syslog.openlog(): 541. when an audit hook raises an exception.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129345


File: python.info,  Node: Core and Builtins<13>,  Next: C API<7>,  Prev: Library<16>,  Up: Python 3 13 2 final

1.23.12.9 Core and Builtins
...........................

   - gh-129093(1): Fix f-strings such as ‘f'{expr=}'’ sometimes not
     displaying the full expression when the expression contains ‘!=’.

   - gh-124363(2): Treat debug expressions in f-string as raw strings.
     Patch by Pablo Galindo

   - gh-128799(3): Add frame of ‘except*’ to traceback when it wraps a
     naked exception.

   - gh-128078(4): Fix a *note SystemError: 578. when using *note
     anext(): 7da. with a default tuple value.  Patch by Bénédikt Tran.

   - gh-128717(5): Fix a crash when setting the recursion limit while
     other threads are active on the *note free threaded: 15b3. build.

   - gh-128330(6): Restore terminal control characters on REPL exit.

   - gh-128079(7): Fix a bug where *note except*: 5bb. does not properly
     check the return value of an *note ExceptionGroup: 1b6.’s *note
     split(): 168f. function, leading to a crash in some cases.  Now
     when ‘split()’ returns an invalid object, ‘except*’ raises a *note
     TypeError: 2c3. with the original raised ‘ExceptionGroup’ object
     chained to it.

   - gh-128030(8): Avoid error from calling ‘PyModule_GetFilenameObject’
     on a non-module object when importing a non-existent symbol from a
     non-module object.

   - gh-127903(9): ‘Objects/unicodeobject.c’: fix a crash on DEBUG
     builds in ‘_copy_characters’ when there is nothing to copy.

   - gh-127599(10): Fix statistics for increments of object reference
     counts (in particular, when a reference count was increased by more
     than 1 in a single operation).

   - gh-127651(11): When raising *note ImportError: 41c. for missing
     symbols in ‘from’ imports, use ‘__file__’ in the error message if
     ‘__spec__.origin’ is not a location

   - gh-127582(12): Fix non-thread-safe object resurrection when calling
     finalizers and watcher callbacks in the free threading build.

   - gh-127434(13): The iOS compiler shims can now accept arguments with
     spaces.

   - gh-127536(14): Add missing locks around some list assignment
     operations in the free threading build.

   - gh-126862(15): Fix a possible overflow when a class inherits from
     an absurd number of super-classes.  Reported by Valery Fedorenko.
     Patch by Bénédikt Tran.

   - gh-127349(16): Fixed the error when resizing terminal in Python
     REPL. Patch by Semyon Moroz.

   - gh-126076(17): Relocated objects such as ‘tuple’, ‘bytes’ and ‘str’
     objects are properly tracked by *note tracemalloc: ff. and its
     associated hooks.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129093

   (2) https://github.com/python/cpython/issues/124363

   (3) https://github.com/python/cpython/issues/128799

   (4) https://github.com/python/cpython/issues/128078

   (5) https://github.com/python/cpython/issues/128717

   (6) https://github.com/python/cpython/issues/128330

   (7) https://github.com/python/cpython/issues/128079

   (8) https://github.com/python/cpython/issues/128030

   (9) https://github.com/python/cpython/issues/127903

   (10) https://github.com/python/cpython/issues/127599

   (11) https://github.com/python/cpython/issues/127651

   (12) https://github.com/python/cpython/issues/127582

   (13) https://github.com/python/cpython/issues/127434

   (14) https://github.com/python/cpython/issues/127536

   (15) https://github.com/python/cpython/issues/126862

   (16) https://github.com/python/cpython/issues/127349

   (17) https://github.com/python/cpython/issues/126076


File: python.info,  Node: C API<7>,  Next: Build<7>,  Prev: Core and Builtins<13>,  Up: Python 3 13 2 final

1.23.12.10 C API
................

   - gh-127791(1): Fix loss of callbacks after more than one call to
     *note PyUnstable_AtExit(): 1691.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127791


File: python.info,  Node: Build<7>,  Prev: C API<7>,  Up: Python 3 13 2 final

1.23.12.11 Build
................

   - gh-129539(1): Don’t redefine ‘EX_OK’ when the system has the
     ‘sysexits.h’ header.

   - gh-128472(2): Skip BOLT optimization of functions using computed
     gotos, fixing errors on build with LLVM 19.

   - gh-123925(3): Fix building the *note curses: 2b. module on
     platforms with libncurses but without libncursesw.

   - gh-128321(4): Set ‘LIBS’ instead of ‘LDFLAGS’ when checking if
     *note sqlite3: cf. library functions are available.  This fixes the
     ordering of linked libraries during checks, which was incorrect
     when using a statically linked ‘libsqlite3’.

   - gh-127865(5): Fix build failure on systems without thread-locals
     support.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/129539

   (2) https://github.com/python/cpython/issues/128472

   (3) https://github.com/python/cpython/issues/123925

   (4) https://github.com/python/cpython/issues/128321

   (5) https://github.com/python/cpython/issues/127865


File: python.info,  Node: Python 3 13 1 final,  Next: Python 3 13 0 final,  Prev: Python 3 13 2 final,  Up: Changelog

1.23.13 Python 3.13.1 final
---------------------------

'Release date: 2024-12-03'

* Menu:

* macOS: macOS<6>.
* Windows: Windows<9>.
* Tools/Demos: Tools/Demos<7>.
* Tests: Tests<10>.
* Security: Security<10>.
* Library: Library<17>.
* IDLE: IDLE<7>.
* Documentation: Documentation<10>.
* Core and Builtins: Core and Builtins<14>.
* Library: Library<18>.
* Core and Builtins: Core and Builtins<15>.
* Library: Library<19>.
* Core and Builtins: Core and Builtins<16>.
* C API: C API<8>.
* Build: Build<8>.


File: python.info,  Node: macOS<6>,  Next: Windows<9>,  Up: Python 3 13 1 final

1.23.13.1 macOS
...............

   - gh-124448(1): Update bundled Tcl/Tk in macOS installer to 8.6.15.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124448


File: python.info,  Node: Windows<9>,  Next: Tools/Demos<7>,  Prev: macOS<6>,  Up: Python 3 13 1 final

1.23.13.2 Windows
.................

   - gh-126911(1): Update credits command output.

   - gh-118973(2): Ensures the experimental free-threaded install
     includes the ‘_tkinter’ module.  The optional Tcl/Tk component must
     also be installed in order for the module to work.

   - gh-126497(3): Fixes venv failure due to missing redirector
     executables in experimental free-threaded installs.

   - gh-126074(4): Removed unnecessary DLLs from Windows embeddable
     package

   - gh-125315(5): Avoid crashing in *note platform: aa. due to slow WMI
     calls on some Windows machines.

   - gh-126084(6): Fix venvwlauncher to launch pythonw instead of python
     so no extra console window is created.

   - gh-125842(7): Fix a *note SystemError: 578. when *note sys.exit():
     1394. is called with ‘0xffffffff’ on Windows.

   - gh-125550(8): Enable the *note Python Launcher for Windows: 5c1. to
     detect Python 3.14 installs from the Windows Store.

   - gh-124448(9): Updated bundled Tcl/Tk to 8.6.15.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126911

   (2) https://github.com/python/cpython/issues/118973

   (3) https://github.com/python/cpython/issues/126497

   (4) https://github.com/python/cpython/issues/126074

   (5) https://github.com/python/cpython/issues/125315

   (6) https://github.com/python/cpython/issues/126084

   (7) https://github.com/python/cpython/issues/125842

   (8) https://github.com/python/cpython/issues/125550

   (9) https://github.com/python/cpython/issues/124448


File: python.info,  Node: Tools/Demos<7>,  Next: Tests<10>,  Prev: Windows<9>,  Up: Python 3 13 1 final

1.23.13.3 Tools/Demos
.....................

   - gh-126807(1): Fix extraction warnings in ‘pygettext.py’ caused by
     mistaking function definitions for function calls.

   - gh-126167(2): The iOS testbed was modified so that it can be used
     by third-party projects for testing purposes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126807

   (2) https://github.com/python/cpython/issues/126167


File: python.info,  Node: Tests<10>,  Next: Security<10>,  Prev: Tools/Demos<7>,  Up: Python 3 13 1 final

1.23.13.4 Tests
...............

   - gh-126909(1): Fix test_os extended attribute tests to work on
     filesystems with 1 KiB xattr size limit.

   - gh-125041(2): Re-enable skipped tests for *note zlib: 133. on the
     s390x architecture: only skip checks of the compressed bytes, which
     can be different between zlib’s software implementation and the
     hardware-accelerated implementation.

   - gh-124295(3): Add translation tests to the *note argparse: 6.
     module.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126909

   (2) https://github.com/python/cpython/issues/125041

   (3) https://github.com/python/cpython/issues/124295


File: python.info,  Node: Security<10>,  Next: Library<17>,  Prev: Tests<10>,  Up: Python 3 13 1 final

1.23.13.5 Security
..................

   - gh-126623(1): Upgrade libexpat to 2.6.4

   - gh-125140(2): Remove the current directory from ‘sys.path’ when
     using PyREPL.

   - gh-122792(3): Changed IPv4-mapped ‘ipaddress.IPv6Address’ to
     consistently use the mapped IPv4 address value for deciding
     properties.  Properties which have their behavior fixed are
     ‘is_multicast’, ‘is_reserved’, ‘is_link_local’, ‘is_global’, and
     ‘is_unspecified’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126623

   (2) https://github.com/python/cpython/issues/125140

   (3) https://github.com/python/cpython/issues/122792


File: python.info,  Node: Library<17>,  Next: IDLE<7>,  Prev: Security<10>,  Up: Python 3 13 1 final

1.23.13.6 Library
.................

   - gh-127321(1): *note pdb.set_trace(): 235. will not stop at an
     opcode that does not have an associated line number anymore.

   - gh-127303(2): Publicly expose *note EXACT_TOKEN_TYPES: 169a. in
     ‘token.__all__’.

   - gh-123967(3): Fix faulthandler for trampoline frames.  If the
     top-most frame is a trampoline frame, skip it.  Patch by Victor
     Stinner.

   - gh-127182(4): Fix ‘io.StringIO.__setstate__()’ crash, when *note
     None: 678. was passed as the first value.

   - gh-127217(5): Fix *note urllib.request.pathname2url(): 169b. for
     paths starting with multiple slashes on Posix.

   - gh-127035(6): Fix *note shutil.which: 4b7. on Windows.  Now it
     looks at direct match if and only if the command ends with a
     PATHEXT extension or X_OK is not in mode.  Support extensionless
     files if “.” is in PATHEXT. Support PATHEXT extensions that end
     with a dot.

   - gh-122273(7): Support PyREPL history on Windows.  Patch by
     devdanzin and Victor Stinner.

   - gh-127078(8): Fix issue where *note urllib.request.url2pathname():
     169c. failed to discard an extra slash before a UNC drive in the
     URL path on Windows.

   - gh-126766(9): Fix issue where *note urllib.request.url2pathname():
     169c. failed to discard any ‘localhost’ authority present in the
     URL.

   - gh-127065(10): Fix crash when calling a *note
     operator.methodcaller(): e67. instance from multiple threads in the
     free threading build.

   - gh-126997(11): Fix support of STRING and GLOBAL opcodes with
     non-ASCII arguments in *note pickletools: a7.  *note
     pickletools.dis(): ce9. now outputs non-ASCII bytes in STRING,
     BINSTRING and SHORT_BINSTRING arguments as escaped (‘\xXX’).

   - gh-126316(12): *note grp: 66.: Make *note grp.getgrall(): 169d.
     thread-safe by adding a mutex.  Patch by Victor Stinner.

   - gh-126618(13): Fix the representation of *note itertools.count:
     12ca. objects when the count value is *note sys.maxsize: 120a.

   - gh-85168(14): Fix issue where *note urllib.request.url2pathname():
     169c. and *note pathname2url(): 169b. always used UTF-8 when
     quoting and unquoting file URIs.  They now use the *note filesystem
     encoding and error handler: 53e.

   - gh-67877(15): Fix memory leaks when *note regular expression: b9.
     matching terminates abruptly, either because of a signal or because
     memory allocation fails.

   - gh-126789(16): Fixed the values of *note
     sysconfig.get_config_vars(): 1069, *note sysconfig.get_paths():
     128a, and their siblings when the *note site: c7. initialization
     happens after *note sysconfig: db. has built a cache for
     ‘sysconfig.get_config_vars()’.

   - gh-126188(17): Update bundled pip to 24.3.1

   - gh-126780(18): Fix *note os.path.normpath(): 1363. for
     drive-relative paths on Windows.

   - gh-126766(19): Fix issue where *note urllib.request.url2pathname():
     169c. failed to discard two leading slashes introducing an empty
     authority section.

   - gh-126727(20): ‘locale.nl_langinfo(locale.ERA)’ now returns
     multiple era description segments separated by semicolons.
     Previously it only returned the first segment on platforms with
     Glibc.

   - gh-126699(21): Allow *note collections.abc.AsyncIterator: e0e. to
     be a base for Protocols.

   - gh-126654(22): Fix crash when non-dict was passed to several
     functions in ‘_interpreters’ module.

   - gh-104745(23): Limit starting a patcher (from *note
     unittest.mock.patch(): ec6. or *note unittest.mock.patch.object():
     169e.) more than once without stopping it

   - gh-126595(24): Fix a crash when instantiating *note
     itertools.count: 12ca. with an initial count of *note sys.maxsize:
     120a. on debug builds.  Patch by Bénédikt Tran.

   - gh-120423(25): Fix issue where *note urllib.request.pathname2url():
     169b. mishandled Windows paths with embedded forward slashes.

   - gh-126565(26): Improve performances of *note zipfile.Path.open():
     169f. for non-reading modes.

   - gh-126505(27): Fix bugs in compiling case-insensitive *note regular
     expressions: b9. with character classes containing non-BMP
     characters: upper-case non-BMP character did was ignored and the
     ASCII flag was ignored when matching a character range whose upper
     bound is beyond the BMP region.

   - gh-117378(28): Fixed the *note multiprocessing: 94. ‘"forkserver"’
     start method forkserver process to correctly inherit the parent’s
     *note sys.path: 3b7. during the importing of *note
     multiprocessing.set_forkserver_preload(): 16a0. modules in the same
     manner as ‘sys.path’ is configured in workers before executing work
     items.

     This bug caused some forkserver module preloading to silently fail
     to preload.  This manifested as a performance degration in child
     processes when the ‘sys.path’ was required due to additional
     repeated work in every worker.

     It could also have a side effect of ‘""’ remaining in *note
     sys.path: 3b7. during forkserver preload imports instead of the
     absolute path from *note os.getcwd(): 16a1. at multiprocessing
     import time used in the worker ‘sys.path’.

     The ‘sys.path’ differences between phases in the child process
     could potentially have caused preload to import incorrect things
     from the wrong location.  We are unaware of that actually having
     happened in practice.

   - gh-125679(29): The *note multiprocessing.Lock: 16a2. and *note
     multiprocessing.RLock: 15c1. ‘repr’ values no longer say “unknown”
     on macOS.

   - gh-126476(30): Raise *note calendar.IllegalMonthError: 16a3. (now a
     subclass of *note IndexError: 1585.) for *note calendar.month():
     16a4. when the input month is not correct.

   - gh-126489(31): The Python implementation of *note pickle: a6. no
     longer calls *note pickle.Pickler.persistent_id(): 16a5. for the
     result of ‘persistent_id()’.

   - gh-126313(32): Fix an issue in *note curses.napms(): 16a6. when
     *note curses.initscr(): 16a7. has not yet been called.  Patch by
     Bénédikt Tran.

   - gh-126303(33): Fix pickling and copying of *note os.sched_param:
     16a8. objects.

   - gh-126138(34): Fix a use-after-free crash on *note asyncio.Task:
     1be. objects whose underlying coroutine yields an object that
     implements an evil *note __getattribute__(): bf1.  Patch by Nico
     Posada.

   - gh-126220(35): Fix crash in ‘cProfile.Profile’ and
     ‘_lsprof.Profiler’ when their callbacks were directly called with 0
     arguments.

   - gh-126212(36): Fix issue where *note urllib.request.pathname2url():
     169b. and *note url2pathname(): 169c. removed slashes from Windows
     DOS drive paths and URLs.

   - gh-126223(37): Raise a *note UnicodeEncodeError: 67a. instead of a
     *note SystemError: 578. upon calling ‘_interpreters.create()’ with
     an invalid Unicode character.

   - gh-126205(38): Fix issue where *note urllib.request.pathname2url():
     169b. generated URLs beginning with four slashes (rather than two)
     when given a Windows UNC path.

   - gh-126105(39): Fix a crash in *note ast: 8. when the *note
     ast.AST._fields: 1606. attribute is deleted.

   - gh-126106(40): Fixes a possible ‘NULL’ pointer dereference in *note
     ssl: d0.

   - gh-126080(41): Fix a use-after-free crash on *note asyncio.Task:
     1be. objects for which the underlying event loop implements an evil
     *note __getattribute__(): bf1.  Reported by Nico-Posada.  Patch by
     Bénédikt Tran.

   - gh-126083(42): Fixed a reference leak in *note asyncio.Task: 1be.
     objects when reinitializing the same object with a non-‘None’
     context.  Patch by Nico Posada.

   - gh-125984(43): Fix use-after-free crashes on *note asyncio.Future:
     bec. objects for which the underlying event loop implements an evil
     *note __getattribute__(): bf1.  Reported by Nico-Posada.  Patch by
     Bénédikt Tran.

   - gh-125969(44): Fix an out-of-bounds crash when an evil *note
     asyncio.loop.call_soon(): b1d. mutates the length of the internal
     callbacks list.  Patch by Bénédikt Tran.

   - gh-125966(45): Fix a use-after-free crash in *note
     asyncio.Future.remove_done_callback(): 16a9.  Patch by Bénédikt
     Tran.

   - gh-125789(46): Fix possible crash when mutating list of callbacks
     returned by ‘asyncio.Future._callbacks’.  It now always returns a
     new copy in C implementation ‘_asyncio’.  Patch by Kumar Aditya.

   - gh-124452(47): Fix an issue in *note
     email.policy.EmailPolicy.header_source_parse(): 16aa. and *note
     email.policy.Compat32.header_source_parse(): 16ab. that introduced
     spurious leading whitespaces into header values when the header
     includes a newline character after the header name delimiter (‘:’)
     and before the value.

   - gh-125884(48): Fixed the bug for *note pdb: a5. where it can’t set
     breakpoints on functions with certain annotations.

   - gh-125355(49): Fix several bugs in *note
     argparse.ArgumentParser.parse_intermixed_args(): b19.

        * The parser no longer changes temporarily during parsing.

        * Default values are not processed twice.

        * Required mutually exclusive groups containing positional
          arguments are now supported.

        * The missing arguments report now includes the names of all
          required optional and positional arguments.

        * Unknown options can be intermixed with positional arguments in
          parse_known_intermixed_args().

   - gh-125666(50): Avoid the exiting the interpreter if a null byte is
     given as input in the new REPL.

   - gh-125710(51): [Enum] fix hashable<->nonhashable comparisons for
     member values

   - gh-125631(52): Restore ability to set *note persistent_id: 16a5.
     and *note persistent_load: 16ac. attributes of instances of the
     ‘Pickler’ and ‘Unpickler’ classes in the *note pickle: a6. module.

   - gh-125378(53): Fixed the bug in *note pdb: a5. where after a
     multi-line command, an empty line repeats the first line of the
     multi-line command, instead of the full command.

   - gh-125682(54): Reject non-ASCII digits in the Python implementation
     of *note json.loads(): 95f. conforming to the JSON specification.

   - gh-125660(55): Reject invalid unicode escapes for Python
     implementation of *note json.loads(): 95f.

   - gh-125259(56): Fix the notes removal logic for errors thrown in
     enum initialization.

   - gh-125590(57): Allow ‘FrameLocalsProxy’ to delete and pop if the
     key is not a fast variable.

   - gh-125519(58): Improve traceback if *note importlib.reload(): 51c.
     is called with an object that is not a module.  Patch by Alex
     Waygood.

   - gh-125451(59): Fix deadlock when *note
     concurrent.futures.ProcessPoolExecutor: 8f7. shuts down
     concurrently with an error when feeding a job to a worker process.

   - gh-125422(60): Fixed the bug where *note pdb: a5. and *note bdb: f.
     can step into the bottom caller frame.

   - gh-100141(61): Fixed the bug where *note pdb: a5. will be stuck in
     an infinite loop when debugging an empty file.

   - gh-125115(62): Fixed a bug in *note pdb: a5. where arguments
     starting with ‘-’ can’t be passed to the debugged script.

   - gh-53203(63): Fix *note time.strptime(): 147b. for ‘%c’, ‘%x’ and
     ‘%X’ formats in many locales that use non-ASCII digits, like
     Persian, Burmese, Odia and Shan.

   - gh-125398(64): Fix the conversion of the ‘VIRTUAL_ENV’ path in the
     activate script in *note venv: 111. when running in Git Bash for
     Windows.

   - gh-125316(65): Fix using *note functools.partial(): 417. as *note
     enum.Enum: 633. member.  A FutureWarning with suggestion to use
     *note enum.member(): 62a. is now emitted when the ‘partial’
     instance is used as an enum member.

   - gh-125245(66): Fix race condition when importing *note
     collections.abc: 1e, which could incorrectly return an empty
     module.

   - gh-125243(67): Fix data race when creating *note zoneinfo.ZoneInfo:
     8e8. objects in the free threading build.

   - gh-125254(68): Fix a bug where ArgumentError includes the incorrect
     ambiguous option in *note argparse: 6.

   - gh-125235(69): Keep *note tkinter: f0. TCL paths in venv pointing
     to base installation on Windows.

   - gh-61011(70): Fix inheritance of nested mutually exclusive groups
     from parent parser in *note argparse.ArgumentParser: 53c.
     Previously, all nested mutually exclusive groups lost their
     connection to the group containing them and were displayed as
     belonging directly to the parser.

   - gh-52551(71): Fix encoding issues in *note time.strftime(): 122e,
     the *note strftime(): cb5. method of the *note datetime: 30.
     classes *note datetime: 1cc, *note date: 1cd. and *note time: 1ce.
     and formatting of these classes.  Characters not encodable in the
     current locale are now acceptable in the format string.  Surrogate
     pairs and sequence of surrogatescape-encoded bytes are no longer
     recombinated.  Embedded null character no longer terminates the
     format string.

   - gh-125118(72): Don’t copy arbitrary values to _Bool in the *note
     struct: d5. module.

   - gh-125069(73): Fix an issue where providing a *note
     pathlib.PurePath: 4a9. object as an initializer argument to a
     second ‘PurePath’ object with a different *note parser: 22c.
     resulted in arguments to the former object’s initializer being
     joined by the latter object’s parser.

   - gh-125096(74): If the *note PYTHON_BASIC_REPL: 16e. environment
     variable is set, the *note site: c7. module no longer imports the
     ‘_pyrepl’ module.  Moreover, the ‘site’ module now respects *note
     -E: 967. and *note -I: 968. command line options: ignore
     ‘PYTHON_BASIC_REPL’ in this case.  Patch by Victor Stinner.

   - gh-124969(75): Fix ‘locale.nl_langinfo(locale.ALT_DIGITS)’ on
     platforms with glibc.  Now it returns a string consisting of up to
     100 semicolon-separated symbols (an empty string in most locales)
     on all Posix platforms.  Previously it only returned the first
     symbol or an empty string.

   - gh-124960(76): Fix support for the ‘barry_as_FLUFL’ future flag in
     the new REPL.

   - gh-124984(77): Fixed thread safety in *note ssl: d0. in the
     free-threaded build.  OpenSSL operations are now protected by a
     per-object lock.

   - gh-124958(78): Fix refcycles in exceptions raised from *note
     asyncio.TaskGroup: 1b5. and the python implementation of *note
     asyncio.Future: bec.

   - gh-53203(79): Fix *note time.strptime(): 147b. for ‘%c’ and ‘%x’
     formats in many locales: Arabic, Bislama, Breton, Bodo, Kashubian,
     Chuvash, Estonian, French, Irish, Ge’ez, Gurajati, Manx Gaelic,
     Hebrew, Hindi, Chhattisgarhi, Haitian Kreyol, Japanese, Kannada,
     Korean, Marathi, Malay, Norwegian, Nynorsk, Punjabi, Rajasthani,
     Tok Pisin, Yoruba, Yue Chinese, Yau/Nungon and Chinese.

   - gh-124917(80): Allow calling *note os.path.exists(): a1b. and *note
     os.path.lexists(): a1c. with keyword arguments on Windows.  Fixes a
     regression in 3.13.0.

   - gh-124653(81): Fix detection of the minimal Queue API needed by the
     *note logging: 87. module.  Patch by Bénédikt Tran.

   - gh-124858(82): Fix reference cycles left in tracebacks in *note
     asyncio.open_connection(): b31. when used with
     ‘happy_eyeballs_delay’

   - gh-124390(83): Fixed *note AssertionError: 6ac. when using
     ‘asyncio.staggered.staggered_race()’ with *note
     asyncio.eager_task_factory: 47a.

   - gh-124651(84): Properly quote template strings in *note venv: 111.
     activation scripts.

   - gh-116850(85): Fix *note argparse: 6. for namespaces with not
     directly writable dict (e.g.  classes).

   - gh-58573(86): Fix conflicts between abbreviated long options in the
     parent parser and subparsers in *note argparse: 6.

   - gh-124594(87): All *note asyncio: a. REPL prompts run in the same
     *note context: 15dd.  Contributed by Bartosz Sławecki.

   - gh-61181(88): Fix support of *note choices: 16ad. with string value
     in *note argparse: 6.  Substrings of the specified string no longer
     considered valid values.

   - gh-80259(89): Fix *note argparse: 6. support of positional
     arguments with ‘nargs='?'’, ‘default=argparse.SUPPRESS’ and
     specified ‘type’.

   - gh-120378(90): Fix a crash related to an integer overflow in *note
     curses.resizeterm(): 16ae. and *note curses.resize_term(): 16af.

   - gh-123884(91): Fixed bug in itertools.tee() handling of other tee
     inputs (a tee in a tee).  The output now has the promised 'n'
     independent new iterators.  Formerly, the first iterator was
     identical (not independent) to the input iterator.  This would
     sometimes give surprising results.

   - gh-58956(92): Fixed a bug in *note pdb: a5. where sometimes the
     breakpoint won’t trigger if it was set on a function which is
     already in the call stack.

   - gh-124345(93): *note argparse: 6. vim supports abbreviated
     single-dash long options separated by ‘=’ from its value.

   - gh-104860(94): Fix disallowing abbreviation of single-dash long
     options in *note argparse: 6. with ‘allow_abbrev=False’.

   - gh-63143(95): Fix parsing mutually exclusive arguments in *note
     argparse: 6.  Arguments with the value identical to the default
     value (e.g.  booleans, small integers, empty or 1-character
     strings) are no longer considered “not present”.

   - gh-72795(96): Positional arguments with *note nargs: 16b0. equal to
     ‘'*'’ or ‘argparse.REMAINDER’ are no longer required.  This allows
     to use positional argument with ‘nargs='*'’ and without ‘default’
     in mutually exclusive group and improves error message about
     required arguments.

   - gh-59317(97): Fix parsing positional argument with *note nargs:
     16b0. equal to ‘'?'’ or ‘'*'’ if it is preceded by an option and
     another positional argument.

   - gh-53780(98): *note argparse: 6. now ignores the first ‘"--"’
     (double dash) between an option and command.

   - gh-124217(99): Add RFC 9637 reserved IPv6 block ‘3fff::/20’ in
     *note ipaddress: 80. module.

   - gh-81691(100): Fix handling of multiple ‘"--"’ (double dashes) in
     *note argparse: 6.  Only the first one has now been removed, all
     subsequent ones are now taken literally.

   - gh-123978(101): Remove broken *note time.thread_time(): 940. and
     *note time.thread_time_ns(): baf. on NetBSD.

   - gh-124008(102): Fix possible crash (in debug build), incorrect
     output or returning incorrect value from raw binary ‘write()’ when
     writing to console on Windows.

   - gh-123935(103): Fix parent slots detection for dataclasses that
     inherit from classes with ‘__dictoffset__’.

   - gh-122765(104): Fix unbalanced quote errors occurring when
     activate.csh in *note venv: 111. was sourced with a custom prompt
     containing unpaired quotes or newlines.

   - gh-123370(105): Fix the canvas not clearing after running
     turtledemo clock.

   - gh-116810(106): Resolve a memory leak introduced in CPython 3.10’s
     *note ssl: d0. when the *note ssl.SSLSocket.session: 16b1. property
     was accessed.  Speeds up read and write access to said property by
     no longer unnecessarily cloning session objects via serialization.

   - gh-120754(107): Update unbounded ‘read’ calls in *note zipfile:
     131. to specify an explicit ‘size’ putting a limit on how much data
     they may read.  This also updates handling around ZIP max comment
     size to match the standard instead of reading comments that are one
     byte too long.

   - gh-70764(108): Fixed an issue where *note inspect.getclosurevars():
     1119. would incorrectly classify an attribute name as a global
     variable when the name exists both as an attribute name and a
     global variable.

   - gh-118289(109): ‘posixpath.realpath()’ now raises *note
     NotADirectoryError: 1098. when 'strict' mode is enabled and a
     non-directory path with a trailing slash is supplied.

   - gh-119826(110): Always return an absolute path for *note
     os.path.abspath(): 1364. on Windows.

   - gh-117766(111): Always use *note str(): 44f. to print ‘choices’ in
     *note argparse: 6.

   - gh-101955(112): Fix SystemError when match regular expression
     pattern containing some combination of possessive quantifier,
     alternative and capture group.

   - gh-88110(113): Fixed *note multiprocessing.Process: b75. reporting
     a ‘.exitcode’ of 1 even on success when using the ‘"fork"’ start
     method while using a *note concurrent.futures.ThreadPoolExecutor:
     745.

   - gh-71936(114): Fix a race condition in *note
     multiprocessing.pool.Pool: fa4.

   - bpo-46128(115): Strip *note unittest.IsolatedAsyncioTestCase: 30c.
     stack frames from reported stacktraces.

   - bpo-14074(116): Fix *note argparse: 6. metavar processing to allow
     positional arguments to have a tuple metavar.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/127321

   (2) https://github.com/python/cpython/issues/127303

   (3) https://github.com/python/cpython/issues/123967

   (4) https://github.com/python/cpython/issues/127182

   (5) https://github.com/python/cpython/issues/127217

   (6) https://github.com/python/cpython/issues/127035

   (7) https://github.com/python/cpython/issues/122273

   (8) https://github.com/python/cpython/issues/127078

   (9) https://github.com/python/cpython/issues/126766

   (10) https://github.com/python/cpython/issues/127065

   (11) https://github.com/python/cpython/issues/126997

   (12) https://github.com/python/cpython/issues/126316

   (13) https://github.com/python/cpython/issues/126618

   (14) https://github.com/python/cpython/issues/85168

   (15) https://github.com/python/cpython/issues/67877

   (16) https://github.com/python/cpython/issues/126789

   (17) https://github.com/python/cpython/issues/126188

   (18) https://github.com/python/cpython/issues/126780

   (19) https://github.com/python/cpython/issues/126766

   (20) https://github.com/python/cpython/issues/126727

   (21) https://github.com/python/cpython/issues/126699

   (22) https://github.com/python/cpython/issues/126654

   (23) https://github.com/python/cpython/issues/104745

   (24) https://github.com/python/cpython/issues/126595

   (25) https://github.com/python/cpython/issues/120423

   (26) https://github.com/python/cpython/issues/126565

   (27) https://github.com/python/cpython/issues/126505

   (28) https://github.com/python/cpython/issues/117378

   (29) https://github.com/python/cpython/issues/125679

   (30) https://github.com/python/cpython/issues/126476

   (31) https://github.com/python/cpython/issues/126489

   (32) https://github.com/python/cpython/issues/126313

   (33) https://github.com/python/cpython/issues/126303

   (34) https://github.com/python/cpython/issues/126138

   (35) https://github.com/python/cpython/issues/126220

   (36) https://github.com/python/cpython/issues/126212

   (37) https://github.com/python/cpython/issues/126223

   (38) https://github.com/python/cpython/issues/126205

   (39) https://github.com/python/cpython/issues/126105

   (40) https://github.com/python/cpython/issues/126106

   (41) https://github.com/python/cpython/issues/126080

   (42) https://github.com/python/cpython/issues/126083

   (43) https://github.com/python/cpython/issues/125984

   (44) https://github.com/python/cpython/issues/125969

   (45) https://github.com/python/cpython/issues/125966

   (46) https://github.com/python/cpython/issues/125789

   (47) https://github.com/python/cpython/issues/124452

   (48) https://github.com/python/cpython/issues/125884

   (49) https://github.com/python/cpython/issues/125355

   (50) https://github.com/python/cpython/issues/125666

   (51) https://github.com/python/cpython/issues/125710

   (52) https://github.com/python/cpython/issues/125631

   (53) https://github.com/python/cpython/issues/125378

   (54) https://github.com/python/cpython/issues/125682

   (55) https://github.com/python/cpython/issues/125660

   (56) https://github.com/python/cpython/issues/125259

   (57) https://github.com/python/cpython/issues/125590

   (58) https://github.com/python/cpython/issues/125519

   (59) https://github.com/python/cpython/issues/125451

   (60) https://github.com/python/cpython/issues/125422

   (61) https://github.com/python/cpython/issues/100141

   (62) https://github.com/python/cpython/issues/125115

   (63) https://github.com/python/cpython/issues/53203

   (64) https://github.com/python/cpython/issues/125398

   (65) https://github.com/python/cpython/issues/125316

   (66) https://github.com/python/cpython/issues/125245

   (67) https://github.com/python/cpython/issues/125243

   (68) https://github.com/python/cpython/issues/125254

   (69) https://github.com/python/cpython/issues/125235

   (70) https://github.com/python/cpython/issues/61011

   (71) https://github.com/python/cpython/issues/52551

   (72) https://github.com/python/cpython/issues/125118

   (73) https://github.com/python/cpython/issues/125069

   (74) https://github.com/python/cpython/issues/125096

   (75) https://github.com/python/cpython/issues/124969

   (76) https://github.com/python/cpython/issues/124960

   (77) https://github.com/python/cpython/issues/124984

   (78) https://github.com/python/cpython/issues/124958

   (79) https://github.com/python/cpython/issues/53203

   (80) https://github.com/python/cpython/issues/124917

   (81) https://github.com/python/cpython/issues/124653

   (82) https://github.com/python/cpython/issues/124858

   (83) https://github.com/python/cpython/issues/124390

   (84) https://github.com/python/cpython/issues/124651

   (85) https://github.com/python/cpython/issues/116850

   (86) https://github.com/python/cpython/issues/58573

   (87) https://github.com/python/cpython/issues/124594

   (88) https://github.com/python/cpython/issues/61181

   (89) https://github.com/python/cpython/issues/80259

   (90) https://github.com/python/cpython/issues/120378

   (91) https://github.com/python/cpython/issues/123884

   (92) https://github.com/python/cpython/issues/58956

   (93) https://github.com/python/cpython/issues/124345

   (94) https://github.com/python/cpython/issues/104860

   (95) https://github.com/python/cpython/issues/63143

   (96) https://github.com/python/cpython/issues/72795

   (97) https://github.com/python/cpython/issues/59317

   (98) https://github.com/python/cpython/issues/53780

   (99) https://github.com/python/cpython/issues/124217

   (100) https://github.com/python/cpython/issues/81691

   (101) https://github.com/python/cpython/issues/123978

   (102) https://github.com/python/cpython/issues/124008

   (103) https://github.com/python/cpython/issues/123935

   (104) https://github.com/python/cpython/issues/122765

   (105) https://github.com/python/cpython/issues/123370

   (106) https://github.com/python/cpython/issues/116810

   (107) https://github.com/python/cpython/issues/120754

   (108) https://github.com/python/cpython/issues/70764

   (109) https://github.com/python/cpython/issues/118289

   (110) https://github.com/python/cpython/issues/119826

   (111) https://github.com/python/cpython/issues/117766

   (112) https://github.com/python/cpython/issues/101955

   (113) https://github.com/python/cpython/issues/88110

   (114) https://github.com/python/cpython/issues/71936

   (115) https://bugs.python.org/issue?@action=redirect&bpo=46128

   (116) https://bugs.python.org/issue?@action=redirect&bpo=14074


File: python.info,  Node: IDLE<7>,  Next: Documentation<10>,  Prev: Library<17>,  Up: Python 3 13 1 final

1.23.13.7 IDLE
..............

   - gh-122392(1): Increase currently inadequate vertical spacing for
     the IDLE browsers (path, module, and stack) on high-resolution
     monitors.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122392


File: python.info,  Node: Documentation<10>,  Next: Core and Builtins<14>,  Prev: IDLE<7>,  Up: Python 3 13 1 final

1.23.13.8 Documentation
.......................

   - gh-126622(1): Added stub pages for removed modules explaining their
     removal, where to find replacements, and linking to the last Python
     version that supported them.  Contributed by Ned Batchelder.

   - gh-125277(2): Require Sphinx 7.2.6 or later to build the Python
     documentation.  Patch by Adam Turner.

   - gh-124872(3): Added definitions for *note context: 16b4, *note
     current context: 16b5, and *note context management protocol: 16b6,
     updated related definitions to be consistent, and expanded the
     documentation for *note contextvars.Context: 15dd.

   - gh-125018(4): The *note importlib.metadata: 7a. documentation now
     includes semantic cross-reference targets for the significant
     documented APIs.  This means intersphinx references like *note
     importlib.metadata.version(): 16b7. will now work as expected.

   - gh-70870(5): Clarified the dual usage of the term “free variable”
     (both the formal meaning of any reference to names defined outside
     the local scope, and the narrower pragmatic meaning of nonlocal
     variables named in ‘co_freevars’).

   - gh-121277(6): Writers of CPython’s documentation can now use ‘next’
     as the version for the ‘versionchanged’, ‘versionadded’,
     ‘deprecated’ directives.

   - gh-60712(7): Include the *note object: a9b. type in the lists of
     documented types.  Change by Furkan Onder and Martin Panter.

   - bpo-34008(8): The *note Py_Main(): c45. documentation moved from
     the “Very High Level API” section to the “Initialization and
     Finalization” section.

     Also make it explicit that we expect ‘Py_Main’ to typically be
     called instead of ‘Py_Initialize’ rather than after it (since
     ‘Py_Main’ makes its own call to ‘Py_Initialize’).  Document that
     calling both is supported but is version dependent on which
     settings will be applied correctly.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126622

   (2) https://github.com/python/cpython/issues/125277

   (3) https://github.com/python/cpython/issues/124872

   (4) https://github.com/python/cpython/issues/125018

   (5) https://github.com/python/cpython/issues/70870

   (6) https://github.com/python/cpython/issues/121277

   (7) https://github.com/python/cpython/issues/60712

   (8) https://bugs.python.org/issue?@action=redirect&bpo=34008


File: python.info,  Node: Core and Builtins<14>,  Next: Library<18>,  Prev: Documentation<10>,  Up: Python 3 13 1 final

1.23.13.9 Core and Builtins
...........................

   - gh-113841(1): Fix possible undefined behavior division by zero in
     *note complex: 2f8.’s *note _Py_c_pow(): 16b9.

   - gh-127020(2): Fix a crash in the free threading build when *note
     PyCode_GetCode(): 77b, *note PyCode_GetVarnames(): 77c, *note
     PyCode_GetCellvars(): 77d, or *note PyCode_GetFreevars(): 77e. were
     called from multiple threads at the same time.

   - gh-126980(3): Fix *note __buffer__(): 462. of *note bytearray: 2ea.
     crashing when *note READ: 16ba. or *note WRITE: 16bb. are passed as
     flags.

   - gh-126881(4): Fix crash in finalization of dtoa state.  Patch by
     Kumar Aditya.

   - gh-126341(5): Now *note ValueError: 202. is raised instead of *note
     SystemError: 578. when trying to iterate over a released *note
     memoryview: 2eb. object.

   - gh-126688(6): Fix a crash when calling *note os.fork(): 197. on
     some operating systems, including SerenityOS.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113841

   (2) https://github.com/python/cpython/issues/127020

   (3) https://github.com/python/cpython/issues/126980

   (4) https://github.com/python/cpython/issues/126881

   (5) https://github.com/python/cpython/issues/126341

   (6) https://github.com/python/cpython/issues/126688


File: python.info,  Node: Library<18>,  Next: Core and Builtins<15>,  Prev: Core and Builtins<14>,  Up: Python 3 13 1 final

1.23.13.10 Library
..................

   - gh-126066(1): Fix *note importlib: 77. to not write an incomplete
     .pyc files when a ulimit or some other operating system mechanism
     is preventing the write to go through fully.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126066


File: python.info,  Node: Core and Builtins<15>,  Next: Library<19>,  Prev: Library<18>,  Up: Python 3 13 1 final

1.23.13.11 Core and Builtins
............................

   - gh-126312(1): Fix crash during garbage collection on an object
     frozen by *note gc.freeze(): b52. on the free-threaded build.

   - gh-126139(2): Provide better error location when attempting to use
     a *note future statement: ddb. with an unknown future feature.

   - gh-126018(3): Fix a crash in *note sys.audit(): 16be. when passing
     a non-string as first argument and Python was compiled in debug
     mode.

   - gh-125942(4): On Android, the ‘errors’ setting of *note sys.stdout:
     aec. was changed from ‘surrogateescape’ to ‘backslashreplace’.

   - gh-125859(5): Fix a crash in the free threading build when *note
     gc.get_objects(): 809. or *note gc.get_referrers(): 80a. is called
     during an in-progress garbage collection.

   - gh-125703(6): Correctly honour *note tracemalloc: ff. hooks in
     specialized ‘Py_DECREF’ paths.  Patch by Pablo Galindo

   - gh-125593(7): Use color to highlight error locations in traceback
     from exception group

   - gh-125444(8): Fix illegal instruction for older Arm architectures.
     Patch by Diego Russo, testing by Ross Burton.

   - gh-124375(9): Fix a crash in the free threading build when the GC
     runs concurrently with a new thread starting.

   - gh-125221(10): Fix possible race condition when calling *note
     __reduce_ex__(): 16bf. for the first time in the free threading
     build.

   - gh-125038(11): Fix crash when iterating over a generator expression
     after direct changes on ‘gi_frame.f_locals’.  Patch by Mikhail
     Efimov.

   - gh-123378(12): Fix a crash in the *note __str__(): 620. method of
     *note UnicodeError: 12eb. objects when the *note
     UnicodeError.start: 16c0. and *note UnicodeError.end: 16c1. values
     are invalid or out-of-range.  Patch by Bénédikt Tran.

   - gh-116510(13): Fix a crash caused by immortal interned strings
     being shared between sub-interpreters that use basic single-phase
     init.  In that case, the string can be used by an interpreter that
     outlives the interpreter that created and interned it.  For
     interpreters that share obmalloc state, also share the interned
     dict with the main interpreter.

   - gh-122878(14): Use the ‘pager’ binary, if available (e.g.  on
     Debian and derivatives), to display REPL ‘help()’.

   - gh-124188(15): Fix reading and decoding a line from the source file
     witn non-UTF-8 encoding for syntax errors raised in the compiler.

   - gh-123930(16): Improve the error message when a script shadowing a
     module from the standard library causes *note ImportError: 41c. to
     be raised during a “from” import.  Similarly, improve the error
     message when a script shadowing a third party module attempts to
     “from” import an attribute from that third party module while still
     initialising.

   - gh-122907(17): Building with ‘HAVE_DYNAMIC_LOADING’ now works as
     well as it did in 3.12.  Existing deficiences will be addressed
     separately.  (See
     ‘https://github.com/python/cpython/issues/122950’.)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126312

   (2) https://github.com/python/cpython/issues/126139

   (3) https://github.com/python/cpython/issues/126018

   (4) https://github.com/python/cpython/issues/125942

   (5) https://github.com/python/cpython/issues/125859

   (6) https://github.com/python/cpython/issues/125703

   (7) https://github.com/python/cpython/issues/125593

   (8) https://github.com/python/cpython/issues/125444

   (9) https://github.com/python/cpython/issues/124375

   (10) https://github.com/python/cpython/issues/125221

   (11) https://github.com/python/cpython/issues/125038

   (12) https://github.com/python/cpython/issues/123378

   (13) https://github.com/python/cpython/issues/116510

   (14) https://github.com/python/cpython/issues/122878

   (15) https://github.com/python/cpython/issues/124188

   (16) https://github.com/python/cpython/issues/123930

   (17) https://github.com/python/cpython/issues/122907


File: python.info,  Node: Library<19>,  Next: Core and Builtins<16>,  Prev: Core and Builtins<15>,  Up: Python 3 13 1 final

1.23.13.12 Library
..................

   - gh-118950(1): Fix bug where SSLProtocol.connection_lost wasn’t
     getting called when OSError was thrown on writing to socket.

   - gh-113570(2): Fixed a bug in ‘reprlib.repr’ where it incorrectly
     called the repr method on shadowed Python built-in types.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118950

   (2) https://github.com/python/cpython/issues/113570


File: python.info,  Node: Core and Builtins<16>,  Next: C API<8>,  Prev: Library<19>,  Up: Python 3 13 1 final

1.23.13.13 Core and Builtins
............................

   - gh-109746(1): If ‘_thread.start_new_thread()’ fails to start a new
     thread, it deletes its state from interpreter and thus avoids its
     repeated cleanup on finalization.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109746


File: python.info,  Node: C API<8>,  Next: Build<8>,  Prev: Core and Builtins<16>,  Up: Python 3 13 1 final

1.23.13.14 C API
................

   - gh-126554(1): Fix error handling in *note ctypes.CDLL: 9f4. objects
     which could result in a crash in rare situations.

   - gh-125608(2): Fix a bug where dictionary watchers (e.g., *note
     PyDict_Watch(): 566.) on an object’s attribute dictionary (*note
     __dict__: 55e.) were not triggered when the object’s attributes
     were modified.

   - bpo-34008(3): Added ‘Py_IsInitialized’ to the list of APIs that are
     safe to call before the interpreter is initialized, and updated the
     embedding tests to cover it.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/126554

   (2) https://github.com/python/cpython/issues/125608

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34008


File: python.info,  Node: Build<8>,  Prev: C API<8>,  Up: Python 3 13 1 final

1.23.13.15 Build
................

   - gh-123877(1): Set ‘wasm32-wasip1’ as the WASI target.  The old
     ‘wasm32-wasi’ target is deprecated so it can be used for an
     eventual WASI 1.0.

   - gh-89640(2): Hard-code float word ordering as little endian on
     WASM.

   - gh-125940(3): The Android build now supports 16 KB page sizes(4).

   - gh-89640(5): Improve detection of float word ordering on Linux when
     link-time optimizations are enabled.

   - gh-125269(6): Fix detection of whether ‘-latomic’ is needed when
     cross-compiling CPython using the configure script.

   - gh-121634(7): Allow for specifying the target compile triple for
     WASI.

   - gh-122578(8): Use WASI SDK 24 for testing.

   - gh-115382(9): Fix cross compile failures when the host and target
     SOABIs match.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123877

   (2) https://github.com/python/cpython/issues/89640

   (3) https://github.com/python/cpython/issues/125940

   (4) https://developer.android.com/guide/practices/page-sizes

   (5) https://github.com/python/cpython/issues/89640

   (6) https://github.com/python/cpython/issues/125269

   (7) https://github.com/python/cpython/issues/121634

   (8) https://github.com/python/cpython/issues/122578

   (9) https://github.com/python/cpython/issues/115382


File: python.info,  Node: Python 3 13 0 final,  Next: Python 3 13 0 release candidate 3,  Prev: Python 3 13 1 final,  Up: Changelog

1.23.14 Python 3.13.0 final
---------------------------

'Release date: 2024-10-07'

* Menu:

* Library: Library<20>.
* Core and Builtins: Core and Builtins<17>.


File: python.info,  Node: Library<20>,  Next: Core and Builtins<17>,  Up: Python 3 13 0 final

1.23.14.1 Library
.................

   - gh-125008(1): Fix *note tokenize.untokenize(): 168a. producing
     invalid syntax for double braces preceded by certain escape
     characters.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/125008


File: python.info,  Node: Core and Builtins<17>,  Prev: Library<20>,  Up: Python 3 13 0 final

1.23.14.2 Core and Builtins
...........................

   - gh-124871(1): Fix compiler bug (in some versions of 3.13) where an
     assertion fails during reachability analysis.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124871


File: python.info,  Node: Python 3 13 0 release candidate 3,  Next: Python 3 13 0 release candidate 2,  Prev: Python 3 13 0 final,  Up: Changelog

1.23.15 Python 3.13.0 release candidate 3
-----------------------------------------

'Release date: 2024-10-01'

* Menu:

* macOS: macOS<7>.
* Windows: Windows<10>.
* Tests: Tests<11>.
* Library: Library<21>.
* IDLE: IDLE<8>.
* Documentation: Documentation<11>.
* Core and Builtins: Core and Builtins<18>.
* C API: C API<9>.
* Build: Build<9>.


File: python.info,  Node: macOS<7>,  Next: Windows<10>,  Up: Python 3 13 0 release candidate 3

1.23.15.1 macOS
...............

   - gh-123797(1): Check for runtime availability of ‘ptsname_r’
     function on macos.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123797


File: python.info,  Node: Windows<10>,  Next: Tests<11>,  Prev: macOS<7>,  Up: Python 3 13 0 release candidate 3

1.23.15.2 Windows
.................

   - gh-124609(1): Fix ‘_Py_ThreadId’ for Windows builds using MinGW.
     Patch by Tony Roberts.

   - gh-124254(2): Ensures experimental free-threaded binaries remain
     installed when updating.

   - gh-123915(3): Ensure that ‘Tools\msi\buildrelease.bat’ uses
     different directories for AMD64 and ARM64 builds.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124609

   (2) https://github.com/python/cpython/issues/124254

   (3) https://github.com/python/cpython/issues/123915


File: python.info,  Node: Tests<11>,  Next: Library<21>,  Prev: Windows<10>,  Up: Python 3 13 0 release candidate 3

1.23.15.3 Tests
...............

   - gh-124378(1): Updated ‘test_ttk’ to pass with Tcl/Tk 8.6.15.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124378


File: python.info,  Node: Library<21>,  Next: IDLE<8>,  Prev: Tests<11>,  Up: Python 3 13 0 release candidate 3

1.23.15.4 Library
.................

   - gh-124538(1): Fixed crash when using *note gc.get_referents(): 80b.
     on a capsule object.

   - gh-124498(2): Fix *note typing.TypeAliasType: 458. not to be
     generic, when ‘type_params’ is an empty tuple.

   - gh-123017(3): Due to unreliable results on some devices, *note
     time.strftime(): 122e. no longer accepts negative years on Android.

   - gh-123014(4): *note os.pidfd_open(): 47d. and *note
     signal.pidfd_send_signal(): 935. are now unavailable when building
     against Android API levels older than 31, since the underlying
     system calls may cause a crash.

   - gh-124248(5): Fixed potential crash when using *note struct: d5. to
     process zero-width ‘Pascal string’ fields (‘0p’).

   - gh-87041(6): Fix a bug in *note argparse: 6. where lengthy
     subparser argument help is incorrectly indented.

   - gh-124212(7): Fix invalid variable in *note venv: 111. handling of
     failed symlink on Windows

   - gh-124171(8): Add workaround for broken ‘fmod()’ implementations on
     Windows, that loose zero sign (e.g.  ‘fmod(-10, 1)’ returns ‘0.0’).
     Patch by Sergey B Kirpichev.

   - gh-123934(9): Fix *note unittest.mock.MagicMock: ec3. reseting
     magic methods return values after ‘.reset_mock(return_value=True)’
     was called.

   - gh-123968(10): Fix the command-line interface for the *note random:
     b8. module to select floats between 0 and N, not 1 and N.

   - gh-123892(11): Add ‘"_wmi"’ to *note sys.stdlib_module_names: 847.
     Patch by Victor Stinner.

   - gh-123339(12): Fix *note inspect.getsource(): 1619. for classes in
     *note collections.abc: 1e. and *note decimal: 36. (for pure Python
     implementation) modules.  *note inspect.getcomments(): 16ce. now
     raises OSError instead of IndexError if the ‘__firstlineno__’ value
     for a class is out of bound.

   - gh-121735(13): When working with zip archives, importlib.resources
     now properly honors module-adjacent references (e.g.
     ‘files(pkg.mod)’ and not just ‘files(pkg)’).

   - gh-122145(14): Fix an issue when reporting tracebacks corresponding
     to Python code emitting an empty AST body.  Patch by Nikita Sobolev
     and Bénédikt Tran.

   - gh-119004(15): Fix a crash in *note OrderedDict.__eq__: 16cf. when
     operands are mutated during the check.  Patch by Bénédikt Tran.

   - bpo-44864(16): Do not translate user-provided strings in *note
     argparse.ArgumentParser: 53c.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124538

   (2) https://github.com/python/cpython/issues/124498

   (3) https://github.com/python/cpython/issues/123017

   (4) https://github.com/python/cpython/issues/123014

   (5) https://github.com/python/cpython/issues/124248

   (6) https://github.com/python/cpython/issues/87041

   (7) https://github.com/python/cpython/issues/124212

   (8) https://github.com/python/cpython/issues/124171

   (9) https://github.com/python/cpython/issues/123934

   (10) https://github.com/python/cpython/issues/123968

   (11) https://github.com/python/cpython/issues/123892

   (12) https://github.com/python/cpython/issues/123339

   (13) https://github.com/python/cpython/issues/121735

   (14) https://github.com/python/cpython/issues/122145

   (15) https://github.com/python/cpython/issues/119004

   (16) https://bugs.python.org/issue?@action=redirect&bpo=44864


File: python.info,  Node: IDLE<8>,  Next: Documentation<11>,  Prev: Library<21>,  Up: Python 3 13 0 release candidate 3

1.23.15.5 IDLE
..............

   - gh-112938(1): Fix uninteruptable hang when Shell gets rapid
     continuous output.

   - gh-120104(2): Fix padding in config and search dialog windows in
     IDLE.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112938

   (2) https://github.com/python/cpython/issues/120104


File: python.info,  Node: Documentation<11>,  Next: Core and Builtins<18>,  Prev: IDLE<8>,  Up: Python 3 13 0 release candidate 3

1.23.15.6 Documentation
.......................

   - gh-124720(1): Update “Using Python on a Mac” section of the “Python
     Setup and Usage” document and include information on installing
     free-threading support.

   - gh-116622(2): Add an Android platform guide, and flag modules not
     available on Android.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124720

   (2) https://github.com/python/cpython/issues/116622


File: python.info,  Node: Core and Builtins<18>,  Next: C API<9>,  Prev: Documentation<11>,  Up: Python 3 13 0 release candidate 3

1.23.15.7 Core and Builtins
...........................

   - gh-124567(1): Revert the incremental GC (in 3.13), since it’s not
     clear the benefits outweigh the costs at this point.

   - gh-124642(2): Fixed scalability issue in free-threaded builds for
     lock-free reads from dictionaries in multi-threaded scenarios

   - gh-116510(3): Fix a bug that can cause a crash when
     sub-interpreters use “basic” single-phase extension modules.
     Shared objects could refer to PyGC_Head nodes that had been freed
     as part of interpreter cleanup.

   - gh-124547(4): When deallocating an object with inline values whose
     ‘__dict__’ is still live: if memory allocation for the inline
     values fails, clear the dictionary.  Prevents an interpreter crash.

   - gh-124513(5): Fix a crash in FrameLocalsProxy constructor: check
     the number of arguments.  Patch by Victor Stinner.

   - gh-124442(6): Fix nondeterminism in compilation by sorting the
     value of *note __static_attributes__: 14b.  Patch by kp2pml30.

   - gh-123856(7): Fix PyREPL failure when a keyboard interrupt is
     triggered after using a history search

   - gh-65961(8): Document the deprecation of setting and using
     ‘__package__’ and ‘__cached__’.

   - gh-124027(9): Support ‘<page up>’, ‘<page down>’, and ‘<delete>’
     keys in the Python REPL when ‘$TERM’ is set to ‘vt100’.

   - gh-77894(10): Fix possible crash in the garbage collector when it
     tries to break a reference loop containing a *note memoryview: 2eb.
     object.  Now a ‘memoryview’ object can only be cleared if there are
     no buffers that refer it.

   - gh-123339(11): Setting the ‘__module__’ attribute for a class now
     removes the ‘__firstlineno__’ item from the type’s dict, so they
     will no longer be inconsistent.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124567

   (2) https://github.com/python/cpython/issues/124642

   (3) https://github.com/python/cpython/issues/116510

   (4) https://github.com/python/cpython/issues/124547

   (5) https://github.com/python/cpython/issues/124513

   (6) https://github.com/python/cpython/issues/124442

   (7) https://github.com/python/cpython/issues/123856

   (8) https://github.com/python/cpython/issues/65961

   (9) https://github.com/python/cpython/issues/124027

   (10) https://github.com/python/cpython/issues/77894

   (11) https://github.com/python/cpython/issues/123339


File: python.info,  Node: C API<9>,  Next: Build<9>,  Prev: Core and Builtins<18>,  Up: Python 3 13 0 release candidate 3

1.23.15.8 C API
...............

   - gh-124160(1): Fix crash when importing modules containing state and
     single-phase initialization in a subinterpreter.

   - gh-123880(2): Fixed a bug that prevented circular imports of
     extension modules that use single-phase initialization.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124160

   (2) https://github.com/python/cpython/issues/123880


File: python.info,  Node: Build<9>,  Prev: C API<9>,  Up: Python 3 13 0 release candidate 3

1.23.15.9 Build
...............

   - gh-124487(1): Windows builds now use Windows 8.1 as their API
     baseline (installation already required Windows 8.1).

   - gh-124043(2): Building using *note -with-trace-refs: 398. is
     (temporarily) disallowed when the GIL is disabled.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/124487

   (2) https://github.com/python/cpython/issues/124043


File: python.info,  Node: Python 3 13 0 release candidate 2,  Next: Python 3 13 0 release candidate 1,  Prev: Python 3 13 0 release candidate 3,  Up: Changelog

1.23.16 Python 3.13.0 release candidate 2
-----------------------------------------

'Release date: 2024-09-06'

* Menu:

* macOS: macOS<8>.
* Windows: Windows<11>.
* Tools/Demos: Tools/Demos<8>.
* Tests: Tests<12>.
* Security: Security<11>.
* Library: Library<22>.
* IDLE: IDLE<9>.
* Library: Library<23>.
* Core and Builtins: Core and Builtins<19>.
* C API: C API<10>.
* Build: Build<10>.


File: python.info,  Node: macOS<8>,  Next: Windows<11>,  Up: Python 3 13 0 release candidate 2

1.23.16.1 macOS
...............

   - gh-123418(1): Updated macOS installer build to use OpenSSL 3.0.15.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123418


File: python.info,  Node: Windows<11>,  Next: Tools/Demos<8>,  Prev: macOS<8>,  Up: Python 3 13 0 release candidate 2

1.23.16.2 Windows
.................

   - gh-123418(1): Updated Windows build to use OpenSSL 3.0.15.

   - gh-122573(2): The Windows build of CPython now requires 3.10 or
     newer.

   - gh-100256(3): *note mimetypes: 8f. no longer fails when it
     encounters an inaccessible registry key.

   - gh-79846(4): Makes ‘ssl.create_default_context()’ ignore invalid
     certificates in the Windows certificate store

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123418

   (2) https://github.com/python/cpython/issues/122573

   (3) https://github.com/python/cpython/issues/100256

   (4) https://github.com/python/cpython/issues/79846


File: python.info,  Node: Tools/Demos<8>,  Next: Tests<12>,  Prev: Windows<11>,  Up: Python 3 13 0 release candidate 2

1.23.16.3 Tools/Demos
.....................

   - gh-123418(1): Update GitHub CI workflows to use OpenSSL 3.0.15 and
     multissltests to use 3.0.15, 3.1.7, and 3.2.3.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123418


File: python.info,  Node: Tests<12>,  Next: Security<11>,  Prev: Tools/Demos<8>,  Up: Python 3 13 0 release candidate 2

1.23.16.4 Tests
...............

   - gh-119727(1): Add ‘--single-process’ command line option to Python
     test runner (regrtest).  Patch by Victor Stinner.

   - gh-101525(2): Skip ‘test_gdb’ if the binary is relocated by BOLT.
     Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119727

   (2) https://github.com/python/cpython/issues/101525


File: python.info,  Node: Security<11>,  Next: Library<22>,  Prev: Tests<12>,  Up: Python 3 13 0 release candidate 2

1.23.16.5 Security
..................

   - gh-123678(1): Upgrade libexpat to 2.6.3

   - gh-121285(2): Remove backtracking from tarfile header parsing for
     ‘hdrcharset’, PAX, and GNU sparse headers.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123678

   (2) https://github.com/python/cpython/issues/121285


File: python.info,  Node: Library<22>,  Next: IDLE<9>,  Prev: Security<11>,  Up: Python 3 13 0 release candidate 2

1.23.16.6 Library
.................

   - gh-123657(1): Fix crash and memory leak in *note
     decimal.getcontext(): 16dc.  It crashed when using a thread-local
     context by ‘--with-decimal-contextvar=no’.

   - gh-123448(2): Fixed memory leak of *note typing.NoDefault: 262. by
     moving it to the static types array.

   - gh-123409(3): Fix *note ipaddress.IPv6Address.reverse_pointer:
     16dd. output according to RFC 3596, §2.5(4).  Patch by Bénédikt
     Tran.

   - gh-123270(5): Applied a more surgical fix for malformed payloads in
     *note zipfile.Path: 6cc. causing infinite loops (gh-122905(6))
     without breaking contents using legitimate characters.

   - gh-123228(7): Fix return type for
     ‘_pyrepl.readline._ReadlineWrapper.get_line_buffer()’ to be *note
     str(): 44f.  Patch by Sergey B Kirpichev.

   - gh-123240(8): Raise audit events for the *note input(): 1320. in
     the new REPL.

   - gh-123243(9): Fix memory leak in ‘_decimal’.

   - gh-122546(10): Consistently use same file name for different
     exceptions in the new repl.  Patch by Sergey B Kirpichev.

   - gh-123213(11): *note xml.etree.ElementTree.Element.extend(): 1218.
     and *note Element: 310. assignment no longer hide the internal
     exception if an erronous generator is passed.  Patch by Bar Harel.

   - gh-85110(12): Preserve relative path in URL without netloc in *note
     urllib.parse.urlunsplit(): 16de. and *note
     urllib.parse.urlunparse(): 16df.

   - gh-123067(13): Fix quadratic complexity in parsing ‘"’-quoted
     cookie values with backslashes by *note http.cookies: 71.

   - gh-122981(14): Fix *note inspect.getsource(): 1619. for generated
     classes with Python base classes (e.g.  enums).

   - gh-122903(15): ‘zipfile.Path.glob’ now correctly matches
     directories instead of silently omitting them.

   - gh-122905(16): *note zipfile.Path: 6cc. objects now sanitize names
     from the zipfile.

   - gh-122695(17): Fixed double-free when using *note
     gc.get_referents(): 80b. with a freed *note asyncio.Future: bec.
     iterator.

   - gh-116263(18): *note logging.handlers.RotatingFileHandler: 16e0. no
     longer rolls over empty log files.

   - gh-105376(19): Restore the deprecated *note logging: 87. ‘warn()’
     method.  It was removed in Python 3.13 alpha 1.  Keep the
     deprecated ‘warn()’ method in Python 3.13.  Patch by Victor
     Stinner.

   - gh-122744(20): Bump the version of pip bundled in ensurepip to
     version 24.2.

   - gh-118814(21): Fix the *note typing.TypeVar: 15d. constructor when
     name is passed by keyword.

   - gh-122478(22): Remove internal frames from tracebacks shown in
     *note code.InteractiveInterpreter: 16e1. with non-default *note
     sys.excepthook(): 811.  Save correct tracebacks in *note
     sys.last_traceback: 4c4. and update ‘__traceback__’ attribute of
     *note sys.last_value: 4c3. and *note sys.last_exc: 4c1.

   - gh-116622(23): On Android, the ‘FICLONE’ and ‘FICLONERANGE’
     constants are no longer exposed by *note fcntl: 59, as these ioctls
     are blocked by SELinux.

   - gh-82378(24): Make sure that the new *note REPL: 16a. interprets
     *note sys.tracebacklimit: 16e2. in the same way that the classic
     REPL did.

   - gh-122334(25): Fix crash when importing *note ssl: d0. after the
     main interpreter restarts.

   - gh-87320(26): In *note code.InteractiveInterpreter: 16e1, handle
     exceptions caused by calling a non-default *note sys.excepthook():
     811.  Before, the exception bubbled up to the caller, ending the
     *note REPL: 16a.

   - gh-121650(27): *note email: 3b. headers with embedded newlines are
     now quoted on output.  The *note generator: 40. will now refuse to
     serialize (write) headers that are unsafely folded or delimited;
     see *note verify_generated_headers: 1e0.  (Contributed by Bas
     Bloemsaat and Petr Viktorin in gh-121650(28).)

   - gh-121723(29): Make *note logging.config.dictConfig(): 11f4. accept
     any object implementing the Queue public API. See the *note queue
     configuration: 16e3. section for details.  Patch by Bénédikt Tran.

   - gh-122081(30): Fix a crash in the ‘decimal.IEEEContext()’ optional
     function available via the ‘EXTRA_FUNCTIONALITY’ configuration
     flag.

   - gh-121804(31): Correctly show error locations, when *note
     SyntaxError: 18d. raised in new repl.  Patch by Sergey B Kirpichev.

   - gh-121151(32): Fix wrapping of long usage text of arguments inside
     a mutually exclusive group in *note argparse: 6.

   - gh-108172(33): ‘webbrowser’ honors OS preferred browser on Linux
     when its desktop entry name contains the text of a known browser
     name.

   - gh-109109(34): You can now get the raw TLS certificate chains from
     TLS connections via *note ssl.SSLSocket.get_verified_chain(): 16e4.
     and *note ssl.SSLSocket.get_unverified_chain(): 16e5. methods.

     Contributed by Mateusz Nowak.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123657

   (2) https://github.com/python/cpython/issues/123448

   (3) https://github.com/python/cpython/issues/123409

   (4) https://datatracker.ietf.org/doc/html/rfc3596.html#section-2.5

   (5) https://github.com/python/cpython/issues/123270

   (6) https://github.com/python/cpython/issues/122905

   (7) https://github.com/python/cpython/issues/123228

   (8) https://github.com/python/cpython/issues/123240

   (9) https://github.com/python/cpython/issues/123243

   (10) https://github.com/python/cpython/issues/122546

   (11) https://github.com/python/cpython/issues/123213

   (12) https://github.com/python/cpython/issues/85110

   (13) https://github.com/python/cpython/issues/123067

   (14) https://github.com/python/cpython/issues/122981

   (15) https://github.com/python/cpython/issues/122903

   (16) https://github.com/python/cpython/issues/122905

   (17) https://github.com/python/cpython/issues/122695

   (18) https://github.com/python/cpython/issues/116263

   (19) https://github.com/python/cpython/issues/105376

   (20) https://github.com/python/cpython/issues/122744

   (21) https://github.com/python/cpython/issues/118814

   (22) https://github.com/python/cpython/issues/122478

   (23) https://github.com/python/cpython/issues/116622

   (24) https://github.com/python/cpython/issues/82378

   (25) https://github.com/python/cpython/issues/122334

   (26) https://github.com/python/cpython/issues/87320

   (27) https://github.com/python/cpython/issues/121650

   (28) https://github.com/python/cpython/issues/121650

   (29) https://github.com/python/cpython/issues/121723

   (30) https://github.com/python/cpython/issues/122081

   (31) https://github.com/python/cpython/issues/121804

   (32) https://github.com/python/cpython/issues/121151

   (33) https://github.com/python/cpython/issues/108172

   (34) https://github.com/python/cpython/issues/109109


File: python.info,  Node: IDLE<9>,  Next: Library<23>,  Prev: Library<22>,  Up: Python 3 13 0 release candidate 2

1.23.16.7 IDLE
..............

   - gh-120083(1): Add explicit black IDLE Hovertip foreground color
     needed for recent macOS. Fixes Sonoma showing unreadable white on
     pale yellow.  Patch by John Riggles.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120083


File: python.info,  Node: Library<23>,  Next: Core and Builtins<19>,  Prev: IDLE<9>,  Up: Python 3 13 0 release candidate 2

1.23.16.8 Library
.................

   - gh-120221(1): asyncio REPL is now again properly recognizing
     KeyboardInterrupts.  Display of exceptions raised in secondary
     threads is fixed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120221


File: python.info,  Node: Core and Builtins<19>,  Next: C API<10>,  Prev: Library<23>,  Up: Python 3 13 0 release candidate 2

1.23.16.9 Core and Builtins
...........................

   - gh-119310(1): Allow the new interactive shell to read history files
     written with the editline library that use unicode-escaped entries.
     Patch by aorcajo and Łukasz Langa.

   - gh-123572(2): Fix key mappings for various F-keys in Windows for
     the new REPL. Patch by devdanzin

   - gh-119034(3): Change ‘<page up>’ and ‘<page down>’ keys of the
     Python REPL to history search forward/backward.  Patch by Victor
     Stinner.

   - gh-123545(4): Fix a double decref in rare cases on experimental JIT
     builds.

   - gh-123484(5): Fix ‘_Py_DebugOffsets’ for long objects to be
     relative to the start of the object rather than the start of a
     subobject.

   - gh-123344(6): Add AST optimizations for type parameter defaults.

   - gh-123321(7): Prevent Parser/myreadline race condition from
     segfaulting on multi-threaded use.  Patch by Bar Harel and Amit
     Wienner.

   - gh-123177(8): Fix a bug causing stray prompts to appear in the
     middle of wrapped lines in the new REPL.

   - gh-122982(9): Extend the deprecation period for bool inversion
     (‘~’) by two years.

   - gh-123275(10): Support *note -X gil=1: 176. and *note PYTHON_GIL=1:
     175. on non-free-threaded builds.

   - gh-123177(11): Deactivate line wrap in the Apple Terminal via a
     ANSI escape code.  Patch by Pablo Galindo

   - gh-123229(12): Fix valgrind warning by initializing the f-string
     buffers to 0 in the tokenizer.  Patch by Pablo Galindo

   - gh-122298(13): Restore printout of GC stats when
     ‘gc.set_debug(gc.DEBUG_STATS)’ is called.  This featue was
     accidentally removed when implementing incremental GC.

   - gh-121804(14): Correctly show error locations when a *note
     SyntaxError: 18d. is raised in the basic REPL. Patch by Sergey B
     Kirpichev.

   - gh-123142(15): Fix too-wide source location in exception tracebacks
     coming from broken iterables in comprehensions.

   - gh-123048(16): Fix a bug where pattern matching code could emit a
     *note JUMP_FORWARD: 16e9. with no source location.

   - gh-123123(17): Fix displaying *note SyntaxError: 18d. exceptions
     covering multiple lines.  Patch by Pablo Galindo

   - gh-123083(18): Fix a potential use-after-free in
     ‘STORE_ATTR_WITH_HINT’.

   - gh-123022(19): Fix crash in free-threaded build when calling *note
     Py_Initialize(): 8b4. from a non-main thread.

   - gh-122888(20): Fix crash on certain calls to ‘str()’ with
     positional arguments of the wrong type.  Patch by Jelle Zijlstra.

   - gh-116622(21): Fix Android stdout and stderr messages being
     truncated or lost.

   - gh-122527(22): Fix a crash that occurred when a ‘PyStructSequence’
     was deallocated after its type’s dictionary was cleared by the GC.
     The type’s *note tp_basicsize: 991. now accounts for non-sequence
     fields that aren’t included in the *note Py_SIZE: 785. of the
     sequence.

   - gh-122445(23): Add only fields which are modified via self.* to
     *note __static_attributes__: 14b.

   - gh-98442(24): Fix too wide source locations of the cleanup
     instructions of a with statement.

   - gh-93691(25): Fix source locations of instructions generated for
     with statements.

   - gh-120097(26): ‘FrameLocalsProxy’ now subclasses
     ‘collections.abc.Mapping’ and can be matched as a mapping in
     ‘match’ statements

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119310

   (2) https://github.com/python/cpython/issues/123572

   (3) https://github.com/python/cpython/issues/119034

   (4) https://github.com/python/cpython/issues/123545

   (5) https://github.com/python/cpython/issues/123484

   (6) https://github.com/python/cpython/issues/123344

   (7) https://github.com/python/cpython/issues/123321

   (8) https://github.com/python/cpython/issues/123177

   (9) https://github.com/python/cpython/issues/122982

   (10) https://github.com/python/cpython/issues/123275

   (11) https://github.com/python/cpython/issues/123177

   (12) https://github.com/python/cpython/issues/123229

   (13) https://github.com/python/cpython/issues/122298

   (14) https://github.com/python/cpython/issues/121804

   (15) https://github.com/python/cpython/issues/123142

   (16) https://github.com/python/cpython/issues/123048

   (17) https://github.com/python/cpython/issues/123123

   (18) https://github.com/python/cpython/issues/123083

   (19) https://github.com/python/cpython/issues/123022

   (20) https://github.com/python/cpython/issues/122888

   (21) https://github.com/python/cpython/issues/116622

   (22) https://github.com/python/cpython/issues/122527

   (23) https://github.com/python/cpython/issues/122445

   (24) https://github.com/python/cpython/issues/98442

   (25) https://github.com/python/cpython/issues/93691

   (26) https://github.com/python/cpython/issues/120097


File: python.info,  Node: C API<10>,  Next: Build<10>,  Prev: Core and Builtins<19>,  Up: Python 3 13 0 release candidate 2

1.23.16.10 C API
................

   - gh-122728(1): Fix *note PyEval_GetLocals(): 356. to avoid *note
     SystemError: 578. (“bad argument to internal function”).  Patch by
     Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122728


File: python.info,  Node: Build<10>,  Prev: C API<10>,  Up: Python 3 13 0 release candidate 2

1.23.16.11 Build
................

   - gh-123418(1): Updated Android build to use OpenSSL 3.0.15.

   - gh-123297(2): Propagate the value of ‘LDFLAGS’ to ‘LDCXXSHARED’ in
     *note sysconfig: db.  Patch by Pablo Galindo

   - gh-116622(3): Rename build variable ‘MODULE_LDFLAGS’ back to
     ‘LIBPYTHON’, as it’s used by package build systems (e.g.  Meson).

   - gh-118943(4): Fix an issue where the experimental JIT could be
     built several times by the ‘make regen-all’ target, leading to
     possible race conditions on heavily parallelized builds.

   - gh-118943(5): Fix a possible race condition affecting parallel
     builds configured with ‘--enable-experimental-jit’, in which *note
     FileNotFoundError: 42e. could be caused by another process already
     moving ‘jit_stencils.h.new’ to ‘jit_stencils.h’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/123418

   (2) https://github.com/python/cpython/issues/123297

   (3) https://github.com/python/cpython/issues/116622

   (4) https://github.com/python/cpython/issues/118943

   (5) https://github.com/python/cpython/issues/118943


File: python.info,  Node: Python 3 13 0 release candidate 1,  Next: Python 3 13 0 beta 4,  Prev: Python 3 13 0 release candidate 2,  Up: Changelog

1.23.17 Python 3.13.0 release candidate 1
-----------------------------------------

'Release date: 2024-07-31'

* Menu:

* Tests: Tests<13>.
* Security: Security<12>.
* Library: Library<24>.
* IDLE: IDLE<10>.
* Core and Builtins: Core and Builtins<20>.
* C API: C API<11>.
* Build: Build<11>.


File: python.info,  Node: Tests<13>,  Next: Security<12>,  Up: Python 3 13 0 release candidate 1

1.23.17.1 Tests
...............

   - gh-59022(1): Add tests for *note pkgutil.extend_path(): 16ee.
     Patch by Andreas Stocker.

   - gh-99242(2): *note os.getloadavg(): 16ef. may throw *note OSError:
     41a. when running regression tests under certain conditions (e.g.
     chroot).  This error is now caught and ignored, since reporting
     load average is optional.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/59022

   (2) https://github.com/python/cpython/issues/99242


File: python.info,  Node: Security<12>,  Next: Library<24>,  Prev: Tests<13>,  Up: Python 3 13 0 release candidate 1

1.23.17.2 Security
..................

   - gh-122133(1): Authenticate the socket connection for the
     ‘socket.socketpair()’ fallback on platforms where ‘AF_UNIX’ is not
     available like Windows.

     Patch by Gregory P. Smith <<greg@krypto.org>> and Seth Larson
     <<seth@python.org>>.  Reported by Ellie <<el@horse64.org>>

   - gh-121957(2): Fixed missing audit events around interactive use of
     Python, now also properly firing for ‘python -i’, as well as for
     ‘python -m asyncio’.  The events in question are
     ‘cpython.run_stdin’ and ‘cpython.run_startup’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122133

   (2) https://github.com/python/cpython/issues/121957


File: python.info,  Node: Library<24>,  Next: IDLE<10>,  Prev: Security<12>,  Up: Python 3 13 0 release candidate 1

1.23.17.3 Library
.................

   - gh-122400(1): Handle *note ValueError: 202.s raised by *note
     os.stat(): 4a3. in *note filecmp.dircmp: f78. and *note
     filecmp.cmpfiles(): 16f2.  Patch by Bénédikt Tran.

   - gh-122311(2): Fix some error messages in *note pickle: a6.

   - gh-122332(3): Fixed segfault with *note asyncio.Task.get_coro():
     9e7. when using an eager task factory.

   - gh-105733(4): *note ctypes.ARRAY(): 29c. is now *note soft
     deprecated: 209.: it no longer emits deprecation warnings and is
     not scheduled for removal.

   - gh-122087(5): Restore *note inspect.ismethoddescriptor(): 16f3. and
     *note inspect.isroutine(): 16f4. returning ‘False’ for *note
     functools.partial: 417. objects.

   - gh-122170(6): Handle *note ValueError: 202.s raised by *note
     os.stat(): 4a3. in *note linecache: 85.  Patch by Bénédikt Tran.

   - gh-82951(7): Serializing objects with complex ‘__qualname__’ (such
     as unbound methods and nested classes) by name no longer involves
     serializing parent objects by value in pickle protocols < 4.

   - gh-113785(8): *note csv: 29. now correctly parses numeric fields
     (when used with *note csv.QUOTE_NONNUMERIC: 16f5. or *note
     csv.QUOTE_STRINGS: 488.) which start with an escape character.

   - gh-122088(9): *note @warnings.deprecated: 160. now copies the
     coroutine status of functions and methods so that *note
     inspect.iscoroutinefunction(): 2e4. returns the correct result.

   - gh-120930(10): Fixed a bug introduced by gh-92081(11) that added an
     incorrect extra blank to encoded words occurring in wrapped
     headers.

   - gh-121474(12): Fix missing sanity check for ‘parties’ arg in *note
     threading.Barrier: 1228. constructor.  Patch by Clinton Christian
     (pygeek).

   - gh-120289(13): Fixed the use-after-free issue in *note cProfile:
     27. by disallowing ‘disable()’ and ‘clear()’ in external timers.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122400

   (2) https://github.com/python/cpython/issues/122311

   (3) https://github.com/python/cpython/issues/122332

   (4) https://github.com/python/cpython/issues/105733

   (5) https://github.com/python/cpython/issues/122087

   (6) https://github.com/python/cpython/issues/122170

   (7) https://github.com/python/cpython/issues/82951

   (8) https://github.com/python/cpython/issues/113785

   (9) https://github.com/python/cpython/issues/122088

   (10) https://github.com/python/cpython/issues/120930

   (11) https://github.com/python/cpython/issues/92081

   (12) https://github.com/python/cpython/issues/121474

   (13) https://github.com/python/cpython/issues/120289


File: python.info,  Node: IDLE<10>,  Next: Core and Builtins<20>,  Prev: Library<24>,  Up: Python 3 13 0 release candidate 1

1.23.17.4 IDLE
..............

   - gh-122482(1): Change About IDLE to direct users to
     discuss.python.org instead of the now unused idle-dev email and
     mailing list.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122482


File: python.info,  Node: Core and Builtins<20>,  Next: C API<11>,  Prev: IDLE<10>,  Up: Python 3 13 0 release candidate 1

1.23.17.5 Core and Builtins
...........................

   - gh-116090(1): Fix an issue in JIT builds that prevented some *note
     for: 2f2. loops from correctly firing *note RAISE: 16f8. monitoring
     events.

   - gh-122208(2): Dictionary watchers now only deliver the
     PyDict_EVENT_ADDED event when the insertion is in a known good
     state to succeed.

   - gh-122300(3): Preserve AST nodes for f-string with single-element
     format specifiers.  Patch by Pablo Galindo

   - gh-120906(4): *note frame.f_locals: 182. now supports arbitrary
     hashable objects as keys.

   - gh-122029(5): Emit ‘c_call’ events in *note sys.setprofile(): 154d.
     when a ‘PyMethodObject’ pointing to a ‘PyCFunction’ is called.

   - gh-122026(6): Fix a bug that caused the tokenizer to not correctly
     identify mismatched parentheses inside f-strings in some
     situations.  Patch by Pablo Galindo

   - gh-118934(7): Make ‘PyEval_GetLocals’ return borrowed reference

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116090

   (2) https://github.com/python/cpython/issues/122208

   (3) https://github.com/python/cpython/issues/122300

   (4) https://github.com/python/cpython/issues/120906

   (5) https://github.com/python/cpython/issues/122029

   (6) https://github.com/python/cpython/issues/122026

   (7) https://github.com/python/cpython/issues/118934


File: python.info,  Node: C API<11>,  Next: Build<11>,  Prev: Core and Builtins<20>,  Up: Python 3 13 0 release candidate 1

1.23.17.6 C API
...............

   - gh-116622(1): Make *note PyObject_Print: 16fa. work around a bug in
     Android and OpenBSD which prevented it from throwing an exception
     when trying to write to a read-only stream.

   - gh-121489(2): Export private ‘_PyBytes_Join()’ again.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116622

   (2) https://github.com/python/cpython/issues/121489


File: python.info,  Node: Build<11>,  Prev: C API<11>,  Up: Python 3 13 0 release candidate 1

1.23.17.7 Build
...............

   - gh-120522(1): Added a *note -with-app-store-compliance: 16fc.
     option to patch out known issues with macOS/iOS App Store review
     processes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120522


File: python.info,  Node: Python 3 13 0 beta 4,  Next: Python 3 13 0 beta 3,  Prev: Python 3 13 0 release candidate 1,  Up: Changelog

1.23.18 Python 3.13.0 beta 4
----------------------------

'Release date: 2024-07-18'

* Menu:

* Tests: Tests<14>.
* Library: Library<25>.
* IDLE: IDLE<11>.
* Documentation: Documentation<12>.
* Core and Builtins: Core and Builtins<21>.
* C API: C API<12>.
* Build: Build<12>.


File: python.info,  Node: Tests<14>,  Next: Library<25>,  Up: Python 3 13 0 beta 4

1.23.18.1 Tests
...............

   - gh-121084(1): Fix test_typing random leaks.  Clear typing ABC
     caches when running tests for refleaks (‘-R’ option): call
     ‘_abc_caches_clear()’ on typing abstract classes and their
     subclasses.  Patch by Victor Stinner.

   - gh-121160(2): Add a test for *note readline.set_history_length():
     16ff.  Note that this test may fail on readline libraries.

   - gh-121200(3): Fix ‘test_expanduser_pwd2()’ of ‘test_posixpath’.
     Call ‘getpwnam()’ to get ‘pw_dir’, since it can be different than
     ‘getpwall()’ ‘pw_dir’.  Patch by Victor Stinner.

   - gh-121188(4): When creating the JUnit XML file, regrtest now
     escapes characters which are invalid in XML, such as the chr(27)
     control character used in ANSI escape sequences.  Patch by Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/121084

   (2) https://github.com/python/cpython/issues/121160

   (3) https://github.com/python/cpython/issues/121200

   (4) https://github.com/python/cpython/issues/121188


File: python.info,  Node: Library<25>,  Next: IDLE<11>,  Prev: Tests<14>,  Up: Python 3 13 0 beta 4

1.23.18.2 Library
.................

   - gh-57141(1): The 'shallow' argument to *note filecmp.dircmp: f78.
     (new in Python 3.13) is now keyword-only.

   - gh-121245(2): Simplify handling of the history file in
     ‘site.register_readline()’ helper.  The ‘CAN_USE_PYREPL’ variable
     now will be initialized, when imported.  Patch by Sergey B
     Kirpichev.

   - gh-121332(3): Fix constructor of *note ast: 8. nodes with custom
     ‘_attributes’.  Previously, passing custom attributes would raise a
     *note DeprecationWarning: 1a5.  Passing arguments to the
     constructor that are not in ‘_fields’ or ‘_attributes’ remains
     deprecated.  Patch by Jelle Zijlstra.

   - gh-121279(4): Avoid *note NameError: 442. for the *note warnings:
     112. module when accessing the depracated atributes of the *note
     importlib.abc: 78. module.

   - gh-121245(5): Fix a bug in the handling of the command history of
     the new *note REPL: 16a. that caused the history file to be wiped
     at REPL exit.

   - gh-87744(6): Fix waitpid race while calling *note send_signal():
     1701. in asyncio.  Patch by Kumar Aditya.

   - gh-121018(7): Fixed other issues where *note
     argparse.ArgumentParser: 53c. did not honor ‘exit_on_error=False’.

   - gh-120678(8): Fix regression in the new REPL that meant that
     globals from files passed using the ‘-i’ argument would not be
     included in the REPL’s global namespace.  Patch by Alex Waygood.

   - gh-120782(9): Fix wrong references of the *note datetime: 30. types
     after reloading the module.

   - gh-120713(10): *note datetime.datetime.strftime(): cb5. now 0-pads
     years with less than four digits for the format specifiers ‘%Y’ and
     ‘%G’ on Linux.  Patch by Ben Hsing

   - gh-117983(11): Defer the ‘threading’ import in ‘importlib.util’
     until lazy loading is used.

   - gh-119189(12): When using the ‘**’ operator or *note pow(): 9dd.
     with *note Fraction: 1e7. as the base and an exponent that is not
     rational, a float, or a complex, the fraction is no longer
     converted to a float.

   - gh-118714(13): Allow ‘restart’ in post-mortem debugging of *note
     pdb: a5.  Removed restart message when the user quits pdb from
     post-mortem mode.

   - gh-105623(14): Fix performance degradation in *note
     logging.handlers.RotatingFileHandler: 16e0.  Patch by Craig Robson.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/57141

   (2) https://github.com/python/cpython/issues/121245

   (3) https://github.com/python/cpython/issues/121332

   (4) https://github.com/python/cpython/issues/121279

   (5) https://github.com/python/cpython/issues/121245

   (6) https://github.com/python/cpython/issues/87744

   (7) https://github.com/python/cpython/issues/121018

   (8) https://github.com/python/cpython/issues/120678

   (9) https://github.com/python/cpython/issues/120782

   (10) https://github.com/python/cpython/issues/120713

   (11) https://github.com/python/cpython/issues/117983

   (12) https://github.com/python/cpython/issues/119189

   (13) https://github.com/python/cpython/issues/118714

   (14) https://github.com/python/cpython/issues/105623


File: python.info,  Node: IDLE<11>,  Next: Documentation<12>,  Prev: Library<25>,  Up: Python 3 13 0 beta 4

1.23.18.3 IDLE
..............

   - gh-78889(1): Stop Shell freezes by blocking user access to
     non-method sys.stdout.shell attributes, which are all private.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/78889


File: python.info,  Node: Documentation<12>,  Next: Core and Builtins<21>,  Prev: IDLE<11>,  Up: Python 3 13 0 beta 4

1.23.18.4 Documentation
.......................

   - gh-121749(1): Fix documentation for *note PyModule_AddObjectRef():
     368.

   - gh-120012(2): Clarify the behaviours of *note
     multiprocessing.Queue.empty(): 1704. and *note
     multiprocessing.SimpleQueue.empty(): 1705. on closed queues.  Patch
     by Bénédikt Tran.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/121749

   (2) https://github.com/python/cpython/issues/120012


File: python.info,  Node: Core and Builtins<21>,  Next: C API<12>,  Prev: Documentation<12>,  Up: Python 3 13 0 beta 4

1.23.18.5 Core and Builtins
...........................

   - gh-121860(1): Fix crash when rematerializing a managed dictionary
     after it was deleted.

   - gh-121814(2): Fixed the SegFault when *note PyEval_SetTrace(): 424.
     is used with no Python frame on stack.

   - gh-121295(3): Fix PyREPL console getting into a blocked state after
     interrupting a long paste

   - gh-121794(4): Fix bug in free-threaded Python where a resurrected
     object could lead to a negative ref count assertion failure.

   - gh-121657(5): Improve the *note SyntaxError: 18d. message if the
     user tries to use *note yield from: 9d8. outside a function.

   - gh-121609(6): Fix pasting of characters containing unicode
     character joiners in the new REPL. Patch by Marta Gomez Macias

   - gh-117482(7): Unexpected slot wrappers are no longer created for
     builtin static types in subinterpreters.

   - gh-121499(8): Fix a bug affecting how multi-line history was being
     rendered in the new REPL after interacting with the new screen
     cache.  Patch by Pablo Galindo

   - gh-121497(9): Fix a bug that was preventing the REPL to correctly
     respect the history when an input hook was set.  Patch by Pablo
     Galindo

   - gh-121012(10): Tier 2 execution now ensures that list iterators
     remain exhausted, once they become exhausted.

   - gh-121439(11): Allow tuples of length 20 in the freelist to be
     reused.

   - gh-121368(12): Fix race condition in ‘_PyType_Lookup’ in the
     free-threaded build due to a missing memory fence.  This could lead
     to ‘_PyType_Lookup’ returning incorrect results on arm64.

   - gh-121130(13): Fix f-strings with debug expressions in format
     specifiers.  Patch by Pablo Galindo

   - gh-121115(14): *note PyLong_AsNativeBytes(): 364. no longer uses
     *note __index__(): 720. methods by default.  The
     ‘Py_ASNATIVEBYTES_ALLOW_INDEX’ flag has been added to allow it.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/121860

   (2) https://github.com/python/cpython/issues/121814

   (3) https://github.com/python/cpython/issues/121295

   (4) https://github.com/python/cpython/issues/121794

   (5) https://github.com/python/cpython/issues/121657

   (6) https://github.com/python/cpython/issues/121609

   (7) https://github.com/python/cpython/issues/117482

   (8) https://github.com/python/cpython/issues/121499

   (9) https://github.com/python/cpython/issues/121497

   (10) https://github.com/python/cpython/issues/121012

   (11) https://github.com/python/cpython/issues/121439

   (12) https://github.com/python/cpython/issues/121368

   (13) https://github.com/python/cpython/issues/121130

   (14) https://github.com/python/cpython/issues/121115


File: python.info,  Node: C API<12>,  Next: Build<12>,  Prev: Core and Builtins<21>,  Up: Python 3 13 0 beta 4

1.23.18.6 C API
...............

   - gh-89364(1): Export the *note PySignal_SetWakeupFd(): 1429.
     function.  Previously, the function was documented but it couldn’t
     be used in 3rd party code.  Patch by Victor Stinner.

   - gh-113993(2): *note PyUnicode_InternInPlace(): 8b9. no longer
     prevents its argument from being garbage collected.

     Several functions that take ‘char *’ are now documented as possibly
     preventing string objects from being garbage collected; refer to
     their documentation for details: *note
     PyUnicode_InternFromString(): 1708, *note PyDict_SetItemString():
     1709, *note PyObject_SetAttrString(): 170a, *note
     PyObject_DelAttrString(): 1640, ‘PyUnicode_InternFromString()’, and
     ‘PyModule_Add*’ convenience functions.

   - gh-113601(3): Removed debug build assertions related to interning
     strings, which were falsely triggered by stable ABI extensions.

   - gh-112136(4): Restore the private ‘_PyArg_Parser’ structure and the
     private ‘_PyArg_ParseTupleAndKeywordsFast()’ function, previously
     removed in Python 3.13 alpha 1.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89364

   (2) https://github.com/python/cpython/issues/113993

   (3) https://github.com/python/cpython/issues/113601

   (4) https://github.com/python/cpython/issues/112136


File: python.info,  Node: Build<12>,  Prev: C API<12>,  Up: Python 3 13 0 beta 4

1.23.18.7 Build
...............

   - gh-120371(1): Support WASI SDK 22 by explicitly skipping functions
     that are just stubs in wasi-libc.

   - gh-121731(2): Fix mimalloc compile error on GNU/Hurd

   - gh-121487(3): Fix deprecation warning for ATOMIC_VAR_INIT in
     mimalloc.

   - gh-121467(4): Fix a Makefile bug that prevented mimalloc header
     files from being installed.

   - gh-121103(5): On POSIX systems, excluding macOS framework installs,
     the lib directory for the free-threaded build now includes a “t”
     suffix to avoid conflicts with a co-located default build
     installation.

   - gh-120831(6): The default minimum iOS version was increased to
     13.0.

   - gh-113565(7): Improve *note curses: 2b. and *note curses.panel: 2d.
     dependency checks in ‘configure’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120371

   (2) https://github.com/python/cpython/issues/121731

   (3) https://github.com/python/cpython/issues/121487

   (4) https://github.com/python/cpython/issues/121467

   (5) https://github.com/python/cpython/issues/121103

   (6) https://github.com/python/cpython/issues/120831

   (7) https://github.com/python/cpython/issues/113565


File: python.info,  Node: Python 3 13 0 beta 3,  Next: Python 3 13 0 beta 2,  Prev: Python 3 13 0 beta 4,  Up: Changelog

1.23.19 Python 3.13.0 beta 3
----------------------------

'Release date: 2024-06-27'

* Menu:

* Core and Builtins: Core and Builtins<22>.
* Library: Library<26>.
* Core and Builtins: Core and Builtins<23>.
* Library: Library<27>.
* Build: Build<13>.
* C API: C API<13>.


File: python.info,  Node: Core and Builtins<22>,  Next: Library<26>,  Up: Python 3 13 0 beta 3

1.23.19.1 Core and Builtins
...........................

   - gh-120838(1): *note Py_Finalize(): 13a6. and *note Py_FinalizeEx():
     d3d. now always run with the main interpreter active.

   - gh-113433(2): Subinterpreters now get cleaned up automatically
     during runtime finalization.

   - gh-119462(3): Make sure that invariants of type versioning are
     maintained: * Superclasses always have their version number
     assigned before subclasses * The version tag is always zero if the
     tag is not valid.  * The version tag is always non-zero if the tag
     is valid.

   - gh-120437(4): Fix ‘_CHECK_STACK_SPACE’ optimization problems
     introduced in gh-118322(5).

   - gh-120722(6): Correctly set the bytecode position on return
     instructions within lambdas.  Patch by Jelle Zijlstra.

   - gh-120367(7): Fix bug where compiler creates a redundant jump
     during pseudo-op replacement.  Can only happen with a synthetic AST
     that has a try on the same line as the instruction following the
     exception handler.

   - gh-113993(8): Strings interned with *note sys.intern(): 1323. are
     again garbage-collected when no longer used, as per the
     documentation.  Strings interned with the C function *note
     PyUnicode_InternInPlace(): 8b9. are still immortal.  Internals of
     the string interning mechanism have been changed.  This may affect
     performance and identities of *note str: 44f. objects.

   - gh-120384(9): Fix an array out of bounds crash in
     ‘list_ass_subscript’, which could be invoked via some specificly
     tailored input: including concurrent modification of a list object,
     where one thread assigns a slice and another clears it.

   - gh-120367(10): Fix crash in compiler on code with redundant NOPs
     and JUMPs which show up after exception handlers are moved to the
     end of the code.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120838

   (2) https://github.com/python/cpython/issues/113433

   (3) https://github.com/python/cpython/issues/119462

   (4) https://github.com/python/cpython/issues/120437

   (5) https://github.com/python/cpython/issues/118322

   (6) https://github.com/python/cpython/issues/120722

   (7) https://github.com/python/cpython/issues/120367

   (8) https://github.com/python/cpython/issues/113993

   (9) https://github.com/python/cpython/issues/120384

   (10) https://github.com/python/cpython/issues/120367


File: python.info,  Node: Library<26>,  Next: Core and Builtins<23>,  Prev: Core and Builtins<22>,  Up: Python 3 13 0 beta 3

1.23.19.2 Library
.................

   - gh-120380(1): Fix Python implementation of *note pickle.Pickler:
     a2b. for *note bytes: 1c2. and *note bytearray: 2ea. objects when
     using protocol version 5.  Patch by Bénédikt Tran.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120380


File: python.info,  Node: Core and Builtins<23>,  Next: Library<27>,  Prev: Library<26>,  Up: Python 3 13 0 beta 3

1.23.19.3 Core and Builtins
...........................

   - gh-120400(1): Support Linux perf profiler to see Python calls on
     RISC-V architecture.

   - gh-120221(2): Deliver real signals on Ctrl-C and Ctrl-Z in the new
     REPL. Patch by Pablo Galindo

   - gh-120346(3): Respect *note PYTHON_BASIC_REPL: 16e. when running in
     interative inspect mode (‘python -i’).  Patch by Pablo Galindo

   - gh-93691(4): Fix source locations of instructions generated for the
     iterator of a for statement.

   - gh-120198(5): Fix a crash when multiple threads read and write to
     the same ‘__class__’ of an object concurrently.

   - gh-120298(6): Fix use-after free in ‘list_richcompare_impl’ which
     can be invoked via some specificly tailored evil input.

   - gh-119666(7): Fix a compiler crash in the case where two
     comprehensions in class scope both reference ‘__class__’.

   - gh-120225(8): Fix crash in compiler on empty block at end of
     exception handler.

   - gh-119933(9): Improve *note SyntaxError: 18d. messages for invalid
     expressions in a type parameters bound, a type parameter constraint
     tuple or a default type parameter.  Patch by Bénédikt Tran.

   - bpo-24766(10): Fix handling of ‘doc’ argument to subclasses of
     ‘property’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120400

   (2) https://github.com/python/cpython/issues/120221

   (3) https://github.com/python/cpython/issues/120346

   (4) https://github.com/python/cpython/issues/93691

   (5) https://github.com/python/cpython/issues/120198

   (6) https://github.com/python/cpython/issues/120298

   (7) https://github.com/python/cpython/issues/119666

   (8) https://github.com/python/cpython/issues/120225

   (9) https://github.com/python/cpython/issues/119933

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24766


File: python.info,  Node: Library<27>,  Next: Build<13>,  Prev: Core and Builtins<23>,  Up: Python 3 13 0 beta 3

1.23.19.4 Library
.................

   - gh-121027(1): Add a future warning in
     ‘functools.partial.__get__()’.  In future Python versions *note
     functools.partial: 417. will be a method descriptor.

   - gh-121025(2): Improve the *note __repr__(): 61f. of *note
     functools.partialmethod: a8a.  Patch by Bénédikt Tran.

   - gh-121018(3): Fixed an issue where
     ‘argparse.ArgumentParser.parses_args()’ did not honor
     ‘exit_on_error=False’ when given unrecognized arguments.  Patch by
     Ben Hsing.

   - gh-119614(4): Fix truncation of strings with embedded null
     characters in some internal operations in *note tkinter: f0.

   - gh-120910(5): When reading installed files from an egg, use
     ‘relative_to(walk_up=True)’ to honor files installed outside of the
     installation root.

   - gh-120888(6): Upgrade pip wheel bundled with ensurepip (pip 24.1.1)

   - gh-101830(7): Accessing the *note tkinter: f0. object’s string
     representation no longer converts the underlying Tcl object to a
     string on Windows.

   - gh-120811(8): Fix possible memory leak in *note
     contextvars.Context.run(): 1711.

   - gh-120769(9): Make empty line in *note pdb: a5. repeats the last
     command even when the command is from ‘cmdqueue’.

   - gh-120732(10): Fix ‘name’ passing to *note unittest.mock.Mock: a58.
     object when using *note unittest.mock.create_autospec(): 1712.

   - gh-120683(11): Fix an error in *note logging.LogRecord: 1021, when
     the integer part of the timestamp is rounded up, while the
     millisecond calculation truncates, causing the log timestamp to be
     wrong by up to 999 ms (affected roughly 1 in 8 million timestamps).

   - gh-120633(12): Move scrollbar and remove tear-off menus in
     turtledemo.

   - gh-120541(13): Improve the prompt in the “less” pager when *note
     help(): 8e0. is called with non-string argument.

   - gh-120495(14): Fix incorrect exception handling in Tab Nanny.
     Patch by Wulian233.

   - gh-120381(15): Correct *note inspect.ismethoddescriptor(): 16f3. to
     check also for the lack of *note __delete__(): 1713.  Patch by Jan
     Kaliszewski.

   - gh-90425(16): The OS byte in gzip headers is now always set to 255
     when using *note gzip.compress(): 641.

   - gh-120343(17): Fix column offset reporting for tokens that come
     after multiline f-strings in the *note tokenize: fb. module.

   - gh-119600(18): Fix *note unittest.mock.patch(): ec6. to not read
     attributes of the target when ‘new_callable’ is set.  Patch by
     Robert Collins.

   - gh-114053(19): Fix edge-case bug where *note
     typing.get_type_hints(): 6b4. would produce incorrect results if
     type parameters in a class scope were overridden by assignments in
     a class scope and ‘from __future__ import annotations’ semantics
     were enabled.  Patch by Alex Waygood.

   - gh-114053(20): Fix erroneous *note NameError: 442. when calling
     *note inspect.get_annotations(): 819. with ‘eval_str=True`’ on a
     class that made use of PEP 695(21) type parameters in a module that
     had ‘from __future__ import annotations’ at the top of the file.
     Patch by Alex Waygood.

   - gh-120268(22): Prohibit passing ‘None’ to pure-Python *note
     datetime.date.fromtimestamp(): bf3. to achieve consistency with
     C-extension implementation.

   - gh-120244(23): Fix memory leak in *note re.sub(): 2a3. when the
     replacement string contains backreferences.

   - gh-120211(24): Fix *note tkinter.ttk: f9. with Tcl/Tk 9.0.

   - gh-71587(25): Fix crash in C version of *note
     datetime.datetime.strptime(): 1714. when called again on the
     restarted interpreter.

   - gh-120161(26): *note datetime: 30. no longer crashes in certain
     complex reference cycle situations.

   - gh-119698(27): Fix *note symtable.Class.get_methods(): 2e5. and
     document its behaviour.  Patch by Bénédikt Tran.

   - gh-120121(28): Add *note concurrent.futures.InvalidStateError:
     1715. to module’s ‘__all__’.

   - gh-119933(29): Add the *note symtable.SymbolTableType: 1716.
     enumeration to represent the possible outputs of the *note
     symtable.SymbolTable.get_type: 1717. method.  Patch by Bénédikt
     Tran.

   - gh-120108(30): Fix calling *note copy.deepcopy(): b8a. on *note
     ast: 8. trees that have been modified to have references to parent
     nodes.  Patch by Jelle Zijlstra.

   - gh-112672(31): Support building *note tkinter: f0. with Tcl 9.0.

   - gh-65454(32): *note unittest.mock.Mock.attach_mock(): 1718. no
     longer triggers a call to a ‘PropertyMock’ being attached.

   - gh-81936(33): ‘help()’ and ‘showtopic()’ methods now respect a
     configured 'output' argument to ‘pydoc.Helper’ and not use the
     pager in such cases.  Patch by Enrico Tröger.

   - gh-119577(34): The *note DeprecationWarning: 1a5. emitted when
     testing the truth value of an *note xml.etree.ElementTree.Element:
     310. now describes unconditionally returning ‘True’ in a future
     version rather than raising an exception in Python 3.14.

   - gh-118908(35): Limit exposed globals from internal imports and
     definitions on new REPL startup.  Patch by Eugene Triguba and Pablo
     Galindo.

   - gh-119506(36): Fix ‘io.TextIOWrapper.write()’ method breaks
     internal buffer when the method is called again during flushing
     internal buffer.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/121027

   (2) https://github.com/python/cpython/issues/121025

   (3) https://github.com/python/cpython/issues/121018

   (4) https://github.com/python/cpython/issues/119614

   (5) https://github.com/python/cpython/issues/120910

   (6) https://github.com/python/cpython/issues/120888

   (7) https://github.com/python/cpython/issues/101830

   (8) https://github.com/python/cpython/issues/120811

   (9) https://github.com/python/cpython/issues/120769

   (10) https://github.com/python/cpython/issues/120732

   (11) https://github.com/python/cpython/issues/120683

   (12) https://github.com/python/cpython/issues/120633

   (13) https://github.com/python/cpython/issues/120541

   (14) https://github.com/python/cpython/issues/120495

   (15) https://github.com/python/cpython/issues/120381

   (16) https://github.com/python/cpython/issues/90425

   (17) https://github.com/python/cpython/issues/120343

   (18) https://github.com/python/cpython/issues/119600

   (19) https://github.com/python/cpython/issues/114053

   (20) https://github.com/python/cpython/issues/114053

   (21) https://peps.python.org/pep-0695/

   (22) https://github.com/python/cpython/issues/120268

   (23) https://github.com/python/cpython/issues/120244

   (24) https://github.com/python/cpython/issues/120211

   (25) https://github.com/python/cpython/issues/71587

   (26) https://github.com/python/cpython/issues/120161

   (27) https://github.com/python/cpython/issues/119698

   (28) https://github.com/python/cpython/issues/120121

   (29) https://github.com/python/cpython/issues/119933

   (30) https://github.com/python/cpython/issues/120108

   (31) https://github.com/python/cpython/issues/112672

   (32) https://github.com/python/cpython/issues/65454

   (33) https://github.com/python/cpython/issues/81936

   (34) https://github.com/python/cpython/issues/119577

   (35) https://github.com/python/cpython/issues/118908

   (36) https://github.com/python/cpython/issues/119506


File: python.info,  Node: Build<13>,  Next: C API<13>,  Prev: Library<27>,  Up: Python 3 13 0 beta 3

1.23.19.5 Build
...............

   - gh-120671(1): Fix failing configure tests due to a missing space
     when appending to CFLAGS.

   - gh-120602(2): Correctly handle LLVM installs with
     ‘LLVM_VERSION_SUFFIX’ when building with
     ‘--enable-experimental-jit’.

   - gh-120326(3): On Windows, fix build error when ‘--disable-gil’ and
     ‘--experimental-jit’ options are combined.

   - gh-120291(4): Make the ‘python-config’ shell script compatible with
     non-bash shells.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120671

   (2) https://github.com/python/cpython/issues/120602

   (3) https://github.com/python/cpython/issues/120326

   (4) https://github.com/python/cpython/issues/120291


File: python.info,  Node: C API<13>,  Prev: Build<13>,  Up: Python 3 13 0 beta 3

1.23.19.6 C API
...............

   - gh-120642(1): Remove the private ‘_Py_CODEUNIT’ type from the
     public C API. The internal ‘pycore_code.h’ header should now be
     used to get this internal type.  Patch by Victor Stinner.

   - gh-120858(2): *note PyDict_Next(): 171b. no longer locks the
     dictionary in the free-threaded build.  The locking needs to be
     done by the caller around the entire iteration loop.

   - gh-120642(3): Remove the following unstable functions:

        * ‘PyUnstable_Replace_Executor()’

        * ‘PyUnstable_SetOptimizer()’

        * ‘PyUnstable_GetOptimizer()’

        * ‘PyUnstable_GetExecutor()’

        * ‘PyUnstable_Optimizer_NewCounter()’

        * ‘PyUnstable_Optimizer_NewUOpOptimizer()’

     Patch by Victor Stinner.

   - gh-119344(4): The critical section API is now public as part of the
     non-limited C API.

   - gh-118789(5): Add *note
     PyUnstable_Object_ClearWeakRefsNoCallbacks(): 171c, which clears
     weakrefs without calling their callbacks.

   - gh-117511(6): Make the *note PyMutex: 15b. public in the
     non-limited C API.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/120642

   (2) https://github.com/python/cpython/issues/120858

   (3) https://github.com/python/cpython/issues/120642

   (4) https://github.com/python/cpython/issues/119344

   (5) https://github.com/python/cpython/issues/118789

   (6) https://github.com/python/cpython/issues/117511


File: python.info,  Node: Python 3 13 0 beta 2,  Next: Python 3 13 0 beta 1,  Prev: Python 3 13 0 beta 3,  Up: Changelog

1.23.20 Python 3.13.0 beta 2
----------------------------

'Release date: 2024-06-05'

* Menu:

* Security: Security<13>.
* Core and Builtins: Core and Builtins<24>.
* Library: Library<28>.
* Tests: Tests<15>.
* Build: Build<14>.
* Windows: Windows<12>.
* C API: C API<14>.


File: python.info,  Node: Security<13>,  Next: Core and Builtins<24>,  Up: Python 3 13 0 beta 2

1.23.20.1 Security
..................

   - gh-118773(1): Fixes creation of ACLs in *note os.mkdir(): 21d. on
     Windows to work correctly on non-English machines.

   - gh-118486(2): *note os.mkdir(): 21d. on Windows now accepts 'mode'
     of ‘0o700’ to restrict the new directory to the current user.  This
     fixes CVE 2024-4030(3) affecting *note tempfile.mkdtemp(): 21f. in
     scenarios where the base temporary directory is more permissive
     than the default.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118773

   (2) https://github.com/python/cpython/issues/118486

   (3) https://www.cve.org/CVERecord?id=CVE-2024-4030


File: python.info,  Node: Core and Builtins<24>,  Next: Library<28>,  Prev: Security<13>,  Up: Python 3 13 0 beta 2

1.23.20.2 Core and Builtins
...........................

   - gh-119724(1): Reverted improvements to error messages for
     ‘elif’/‘else’ statements not matching any valid statements, which
     made in hard to locate the syntax errors inside those ‘elif’/‘else’
     blocks.

   - gh-119842(2): Honor *note PyOS_InputHook(): 588. in the new REPL.
     Patch by Pablo Galindo

   - gh-119821(3): Fix execution of *note annotation scopes: 188. within
     classes when ‘globals’ is set to a non-dict.  Patch by Jelle
     Zijlstra.

   - gh-119548(4): Add a ‘clear’ command to the REPL. Patch by Pablo
     Galindo

   - gh-111999(5): Fix the signature of *note str.format_map(): e07.

   - gh-119560(6): An invalid assert in beta 1 has been removed.  The
     assert would fail if ‘PyState_FindModule()’ was used in an
     extension module’s init function before the module def had been
     initialized.

   - gh-119369(7): Fix deadlock during thread deletion in free-threaded
     build, which could occur when the GIL was enabled at runtime.

   - gh-119525(8): Fix deadlock involving ‘_PyType_Lookup()’ cache in
     the free-threaded build when the GIL is dynamically enabled at
     runtime.

   - gh-119311(9): Fix bug where names are unexpectedly mangled in the
     bases of generic classes.

   - gh-119395(10): Fix bug where names appearing after a generic class
     are mangled as if they are in the generic class.

   - gh-119213(11): Non-builtin modules built with argument clinic were
     crashing if used in a subinterpreter before the main interpreter.
     The objects that were causing the problem by leaking between
     interpreters carelessly have been fixed.

   - gh-119011(12): Fixes ‘type.__type_params__’ to return an empty
     tuple instead of a descriptor.

   - gh-118692(13): Avoid creating unnecessary *note StopIteration: c1b.
     instances for monitoring.

   - gh-119049(14): Fix displaying the source line for warnings created
     by the C API if the *note warnings: 112. module had not yet been
     imported.

   - gh-118844(15): Fix build failures when configuring with both
     ‘--disable-gil’ and ‘--enable-experimental-jit’.

   - gh-118921(16): Add ‘copy()’ method for ‘FrameLocalsProxy’ which
     returns a snapshot ‘dict’ for local variables.

   - gh-117657(17): Fix data races on the field that stores a pointer to
     the interpreter’s main thread that occur in free-threaded builds.

   - gh-118561(18): Fix race condition in free-threaded build where
     ‘list.extend()’ could expose uninitialised memory to concurrent
     readers.

   - gh-117195(19): Avoid assertion failure for debug builds when
     calling ‘object.__sizeof__(1)’

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119724

   (2) https://github.com/python/cpython/issues/119842

   (3) https://github.com/python/cpython/issues/119821

   (4) https://github.com/python/cpython/issues/119548

   (5) https://github.com/python/cpython/issues/111999

   (6) https://github.com/python/cpython/issues/119560

   (7) https://github.com/python/cpython/issues/119369

   (8) https://github.com/python/cpython/issues/119525

   (9) https://github.com/python/cpython/issues/119311

   (10) https://github.com/python/cpython/issues/119395

   (11) https://github.com/python/cpython/issues/119213

   (12) https://github.com/python/cpython/issues/119011

   (13) https://github.com/python/cpython/issues/118692

   (14) https://github.com/python/cpython/issues/119049

   (15) https://github.com/python/cpython/issues/118844

   (16) https://github.com/python/cpython/issues/118921

   (17) https://github.com/python/cpython/issues/117657

   (18) https://github.com/python/cpython/issues/118561

   (19) https://github.com/python/cpython/issues/117195


File: python.info,  Node: Library<28>,  Next: Tests<15>,  Prev: Core and Builtins<24>,  Up: Python 3 13 0 beta 2

1.23.20.3 Library
.................

   - gh-119819(1): Fix regression to allow logging configuration with
     multiprocessing queue types.

   - gh-117142(2): The *note ctypes: 2a. module may now be imported in
     all subinterpreters, including those that have their own GIL.

   - gh-118835(3): Fix _pyrepl crash when using custom prompt with ANSI
     escape codes.

   - gh-117398(4): The ‘_datetime’ module (C implementation for *note
     datetime: 30.) now supports being imported in multiple
     interpreters.

   - gh-89727(5): Fix issue with *note shutil.rmtree(): 301. where a
     *note RecursionError: d96. is raised on deep directory trees.

   - gh-89727(6): Partially fix issue with *note shutil.rmtree(): 301.
     where a *note RecursionError: d96. is raised on deep directory
     trees.  A recursion error is no longer raised when
     ‘rmtree.avoids_symlink_attacks’ is false.

   - gh-119118(7): Fix performance regression in the *note tokenize: fb.
     module by caching the ‘line’ token attribute and calculating the
     column offset more efficiently.

   - gh-89727(8): Fix issue with *note os.fwalk(): b77. where a *note
     RecursionError: d96. was raised on deep directory trees by
     adjusting the implementation to be iterative instead of recursive.

   - gh-119588(9): ‘zipfile.Path.is_symlink’ now assesses if the given
     path is a symlink.

   - gh-119555(10): Catch *note SyntaxError: 18d. from *note compile():
     192. in the runsource() method of the InteractiveColoredConsole.
     Patch by Sergey B Kirpichev.

   - gh-113892(11): Now, the method ‘sock_connect’ of *note
     asyncio.ProactorEventLoop: 60c. raises a *note ValueError: 202. if
     given socket is not in non-blocking mode, as well as in other loop
     implementations.

   - gh-119443(12): The interactive REPL no longer runs with ‘from
     __future__ import annotations’ enabled.  Patch by Jelle Zijlstra.

   - gh-117398(13): Objects in the datetime C-API are now all statically
     allocated, which means better memory safety, especially when the
     module is reloaded.  This should be transparent to users.

   - gh-118894(14): *note asyncio: a. REPL now has the same capabilities
     as PyREPL.

   - gh-118911(15): In PyREPL, updated ‘maybe-accept’’s logic so that if
     the user hits ‘Enter’ twice, they are able to terminate the block
     even if there’s trailing whitespace.  Also, now when the user hits
     arrow up, the cursor is on the last functional line.  This matches
     IPython’s behavior.  Patch by Aya Elsayed.

   - gh-111201(16): Remove dependency to *note readline: ba. from the
     new Python REPL.

   - gh-119174(17): Fix high DPI causes turtledemo(turtle-graphics
     examples) windows blurry Patch by Wulian233 and Terry Jan Reedy

   - gh-119121(18): Fix a NameError happening in
     ‘asyncio.staggered.staggered_race’.  This function is now tested.

   - gh-119113(19): Fix issue where *note
     pathlib.PurePath.with_suffix(): 1721. didn’t raise *note TypeError:
     2c3. when given ‘None’ as a suffix.

   - gh-118643(20): Fix an AttributeError in the *note email: 3b. module
     when re-fold a long address list.  Also fix more cases of incorrect
     encoding of the address separator in the address list.

   - gh-58933(21): Make *note pdb: a5. return to caller frame correctly
     when ‘f_trace’ of the caller frame is not set

   - gh-118895(22): Setting attributes on *note typing.NoDefault: 262.
     now raises *note AttributeError: 34e. instead of *note TypeError:
     2c3.

   - gh-118868(23): Fixed issue where kwargs were no longer passed to
     the logging handler QueueHandler

   - gh-118851(24): ‘ctx’ arguments to the constructors of *note ast: 8.
     node classes now default to *note ast.Load(): 1a4.  Patch by Jelle
     Zijlstra.

   - gh-118760(25): Restore the default value of ‘tkiter.wantobjects’ to
     ‘1’.

   - gh-118760(26): Fix errors in calling Tkinter bindings on Windows.

   - gh-118507(27): Fix *note os.path.isfile(): a1e. on Windows for
     pipes.  Speedup *note os.path.isjunction(): 4a6. and *note
     os.path.lexists(): a1c. on Windows with a native implementation.

   - gh-118772(28): Allow *note typing.TypeVar: 15d. instances without a
     default to follow instances without a default in some cases.  Patch
     by Jelle Zijlstra.

   - gh-110863(29): *note os.path.realpath(): 225. now suppresses any
     *note OSError: 41a. from *note os.readlink(): 929. when 'strict'
     mode is disabled (the default).

   - gh-118263(30): Speed up *note os.path.splitroot(): 4a7. & *note
     os.path.normpath(): 1363. with a direct C call.

   - gh-118033(31): Fix *note dataclasses.dataclass(): 1cb. not creating
     a ‘__weakref__’ slot when subclassing *note typing.Generic: 15fb.

   - gh-106531(32): In *note importlib.resources: 7b, sync with
     importlib_resources 6.3.2(33), including: ‘MultiplexedPath’ now
     expects ‘Traversable’ paths, deprecating string arguments to
     ‘MultiplexedPath’; Enabled support for resources in namespace
     packages in zip files; Fixed ‘NotADirectoryError’ when calling
     files on a subdirectory of a namespace package.

   - gh-113978(34): Ignore warnings on text completion inside REPL.

   - gh-103956(35): Fix lack of newline characters in *note trace: fd.
     module output when line tracing is enabled but source code line for
     current frame is not available.

   - gh-92081(36): Fix missing spaces in email headers when the spaces
     are mixed with encoded 8-bit characters.

   - gh-103194(37): Prepare Tkinter for C API changes in Tcl 8.7/9.0 to
     avoid ‘_tkinter.Tcl_Obj’ being unexpectedly returned instead of
     *note bool: 46b, *note str: 44f, *note bytearray: 2ea, or *note
     int: 257.

   - gh-87106(38): Fixed handling in *note inspect.Signature.bind():
     1667. of keyword arguments having the same name as positional-only
     arguments when a variadic keyword argument (e.g.  ‘**kwargs’) is
     present.

   - bpo-45767(39): Fix integer conversion in *note os.major(): 1722,
     *note os.minor(): 1723, and *note os.makedev(): 1724.  Support
     device numbers larger than ‘2**63-1’.  Support non-existent device
     number (‘NODEV’).

   - gh-67693(40): Fix *note urllib.parse.urlunparse(): 16df. and *note
     urllib.parse.urlunsplit(): 16de. for URIs with path starting with
     multiple slashes and no authority.  Based on patch by Ashwin
     Ramaswami.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119819

   (2) https://github.com/python/cpython/issues/117142

   (3) https://github.com/python/cpython/issues/118835

   (4) https://github.com/python/cpython/issues/117398

   (5) https://github.com/python/cpython/issues/89727

   (6) https://github.com/python/cpython/issues/89727

   (7) https://github.com/python/cpython/issues/119118

   (8) https://github.com/python/cpython/issues/89727

   (9) https://github.com/python/cpython/issues/119588

   (10) https://github.com/python/cpython/issues/119555

   (11) https://github.com/python/cpython/issues/113892

   (12) https://github.com/python/cpython/issues/119443

   (13) https://github.com/python/cpython/issues/117398

   (14) https://github.com/python/cpython/issues/118894

   (15) https://github.com/python/cpython/issues/118911

   (16) https://github.com/python/cpython/issues/111201

   (17) https://github.com/python/cpython/issues/119174

   (18) https://github.com/python/cpython/issues/119121

   (19) https://github.com/python/cpython/issues/119113

   (20) https://github.com/python/cpython/issues/118643

   (21) https://github.com/python/cpython/issues/58933

   (22) https://github.com/python/cpython/issues/118895

   (23) https://github.com/python/cpython/issues/118868

   (24) https://github.com/python/cpython/issues/118851

   (25) https://github.com/python/cpython/issues/118760

   (26) https://github.com/python/cpython/issues/118760

   (27) https://github.com/python/cpython/issues/118507

   (28) https://github.com/python/cpython/issues/118772

   (29) https://github.com/python/cpython/issues/110863

   (30) https://github.com/python/cpython/issues/118263

   (31) https://github.com/python/cpython/issues/118033

   (32) https://github.com/python/cpython/issues/106531

   (33) 
https://importlib-resources.readthedocs.io/en/latest/history.html#v6-3-2

   (34) https://github.com/python/cpython/issues/113978

   (35) https://github.com/python/cpython/issues/103956

   (36) https://github.com/python/cpython/issues/92081

   (37) https://github.com/python/cpython/issues/103194

   (38) https://github.com/python/cpython/issues/87106

   (39) https://bugs.python.org/issue?@action=redirect&bpo=45767

   (40) https://github.com/python/cpython/issues/67693


File: python.info,  Node: Tests<15>,  Next: Build<14>,  Prev: Library<28>,  Up: Python 3 13 0 beta 2

1.23.20.4 Tests
...............

   - gh-119050(1): regrtest test runner: Add XML support to the refleak
     checker (-R option).  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119050


File: python.info,  Node: Build<14>,  Next: Windows<12>,  Prev: Tests<15>,  Up: Python 3 13 0 beta 2

1.23.20.5 Build
...............

   - gh-119729(1): On POSIX systems, the pkg-config (‘.pc’) filenames
     now include the ABI flags, which may include debug (“d”) and
     free-threaded (“t”).  For example: * ‘python-3.14.pc’ (default,
     non-debug build) * ‘python-3.14d.pc’ (default, debug build) *
     ‘python-3.14t.pc’ (free-threaded build)

   - gh-115119(2): Fall back to the bundled libmpdec if a system version
     cannot be found.

   - gh-119132(3): Update *note sys.version: 178. to identify whether
     the build is default build or free-threading build.  Patch By
     Donghee Na.

   - gh-118836(4): Fix an ‘AssertionError’ when building with
     ‘--enable-experimental-jit’ and the compiler emits a ‘SHT_NOTE’
     section.

   - gh-118943(5): Fix a possible race condition affecting parallel
     builds configured with ‘--enable-experimental-jit’, in which
     compilation errors could be caused by an incompletely-generated
     header file.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119729

   (2) https://github.com/python/cpython/issues/115119

   (3) https://github.com/python/cpython/issues/119132

   (4) https://github.com/python/cpython/issues/118836

   (5) https://github.com/python/cpython/issues/118943


File: python.info,  Node: Windows<12>,  Next: C API<14>,  Prev: Build<14>,  Up: Python 3 13 0 beta 2

1.23.20.6 Windows
.................

   - gh-119679(1): Ensures correct import libraries are included in
     Windows installs.

   - gh-119690(2): Adds Unicode support and fixes audit events for
     ‘_winapi.CreateNamedPipe’.

   - gh-111201(3): Add support for new pyrepl on Windows

   - gh-119070(4): Fixes ‘py.exe’ handling of shebangs like
     ‘/usr/bin/env python3.12’, which were previously interpreted as
     ‘python3.exe’ instead of ‘python3.12.exe’.

   - gh-117505(5): Fixes an issue with the Windows installer not running
     ensurepip in a fully isolated environment.  This could cause
     unexpected interactions with the user site-packages.

   - gh-118209(6): Avoid crashing in *note mmap: 90. on Windows when the
     mapped memory is inaccessible due to file system errors or access
     violations.

   - gh-116145(7): Updated bundled Tcl/Tk to 8.6.14.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119679

   (2) https://github.com/python/cpython/issues/119690

   (3) https://github.com/python/cpython/issues/111201

   (4) https://github.com/python/cpython/issues/119070

   (5) https://github.com/python/cpython/issues/117505

   (6) https://github.com/python/cpython/issues/118209

   (7) https://github.com/python/cpython/issues/116145


File: python.info,  Node: C API<14>,  Prev: Windows<12>,  Up: Python 3 13 0 beta 2

1.23.20.7 C API
...............

   - gh-119585(1): Fix crash when a thread state that was created by
     *note PyGILState_Ensure(): 3ae. calls a destructor that during
     *note PyThreadState_Clear(): 1729. that calls back into
     ‘PyGILState_Ensure()’ and *note PyGILState_Release(): 3af.  This
     might occur when in the free-threaded build or when using
     thread-local variables whose destructors call
     ‘PyGILState_Ensure()’.

   - gh-119336(2): Restore the removed ‘_PyLong_NumBits()’ function.  It
     is used by the pywin32 project.  Patch by Ethan Smith

   - gh-119247(3): Added ‘Py_BEGIN_CRITICAL_SECTION_SEQUENCE_FAST’ and
     ‘Py_END_CRITICAL_SECTION_SEQUENCE_FAST’ macros to make it possible
     to use PySequence_Fast APIs safely when free-threaded, and update
     str.join to work without the GIL using them.

   - gh-111389(4): Add *note PyHASH_MULTIPLIER: 172a. constant: prime
     multiplier used in string and various other hashes.  Patch by
     Victor Stinner.

   - gh-116984(5): Make mimalloc includes relative to the current file
     to avoid embedders or extensions needing to include
     ‘Internal/mimalloc’ if they are already including internal CPython
     headers.

   - gh-118789(6): Restore ‘_PyWeakref_ClearRef’ that was previously
     removed in Python 3.13 alpha 1.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/119585

   (2) https://github.com/python/cpython/issues/119336

   (3) https://github.com/python/cpython/issues/119247

   (4) https://github.com/python/cpython/issues/111389

   (5) https://github.com/python/cpython/issues/116984

   (6) https://github.com/python/cpython/issues/118789


File: python.info,  Node: Python 3 13 0 beta 1,  Next: Python 3 13 0 alpha 6,  Prev: Python 3 13 0 beta 2,  Up: Changelog

1.23.21 Python 3.13.0 beta 1
----------------------------

'Release date: 2024-05-08'

* Menu:

* Security: Security<14>.
* Core and Builtins: Core and Builtins<25>.
* Library: Library<29>.
* Core and Builtins: Core and Builtins<26>.
* Library: Library<30>.
* Documentation: Documentation<13>.
* Build: Build<15>.
* Windows: Windows<13>.
* macOS: macOS<9>.
* IDLE: IDLE<12>.
* C API: C API<15>.


File: python.info,  Node: Security<14>,  Next: Core and Builtins<25>,  Up: Python 3 13 0 beta 1

1.23.21.1 Security
..................

   - gh-116741(1): Update bundled libexpat to 2.6.2

   - gh-117233(2): Detect BLAKE2, SHA3, Shake, & truncated SHA512
     support in the OpenSSL-ish libcrypto library at build time.  This
     allows *note hashlib: 68. to be used with libraries that do not to
     support every algorithm that upstream OpenSSL does.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116741

   (2) https://github.com/python/cpython/issues/117233


File: python.info,  Node: Core and Builtins<25>,  Next: Library<29>,  Prev: Security<14>,  Up: Python 3 13 0 beta 1

1.23.21.2 Core and Builtins
...........................

   - gh-118414(1): Add instrumented opcodes to YIELD_VALUE assertion for
     tracing cases.

   - gh-117953(2): When a builtin or extension module is imported for
     the first time, while a subinterpreter is active, the module’s init
     function is now run by the main interpreter first before import
     continues in the subinterpreter.  Consequently, single-phase init
     modules now fail in an isolated subinterpreter without the init
     function running under that interpreter, whereas before it would
     run under the subinterpreter 'before' failing, potentially leaving
     behind global state and callbacks and otherwise leaving the module
     in an inconsistent state.

   - gh-117549(3): Don’t use designated initializer syntax in inline
     functions in internal headers.  They cause problems for C++ or MSVC
     users who aren’t yet using the latest C++ standard (C++20).  While
     internal, pycore_backoff.h, is included (indirectly, via
     pycore_code.h) by some key 3rd party software that does so for
     speed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118414

   (2) https://github.com/python/cpython/issues/117953

   (3) https://github.com/python/cpython/issues/117549


File: python.info,  Node: Library<29>,  Next: Core and Builtins<26>,  Prev: Core and Builtins<25>,  Up: Python 3 13 0 beta 1

1.23.21.3 Library
.................

   - gh-95382(1): Improve performance of *note json.dumps(): d6e. and
     *note json.dump(): d6d. when using the argument 'indent'.
     Depending on the data the encoding using ‘json.dumps()’ with
     'indent' can be up to 2 to 3 times faster.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95382


File: python.info,  Node: Core and Builtins<26>,  Next: Library<30>,  Prev: Library<29>,  Up: Python 3 13 0 beta 1

1.23.21.4 Core and Builtins
...........................

   - gh-116322(1): In ‘--disable-gil’ builds, the GIL will be enabled
     while loading C extension modules.  If the module indicates that it
     supports running without the GIL, the GIL will be disabled once
     loading is complete.  Otherwise, the GIL will remain enabled for
     the remainder of the interpreter’s lifetime.  This behavior does
     not apply if the GIL has been explicitly enabled or disabled with
     ‘PYTHON_GIL’ or ‘-Xgil’.

   - gh-118513(2): Fix incorrect *note UnboundLocalError: 1586. when two
     comprehensions in the same function both reference the same name,
     and in one comprehension the name is bound while in the other it’s
     an implicit global.

   - gh-118518(3): Allow the Linux perf support to work without frame
     pointers using perf’s advanced JIT support.  The feature is
     activated when using the ‘PYTHON_PERF_JIT_SUPPORT’ environment
     variable or when running Python with ‘-Xperf_jit’.  Patch by Pablo
     Galindo.

   - gh-117514(4): Add ‘sys._is_gil_enabled()’ function that returns
     whether the GIL is currently enabled.  In the default build it
     always returns ‘True’ because the GIL is always enabled.  In the
     free-threaded build, it may return ‘True’ or ‘False’.

   - gh-118164(5): Break a loop between the Python implementation of the
     *note decimal: 36. module and the Python code for integer to string
     conversion.  Also optimize integer to string conversion for values
     in the range from 9_000 to 135_000 decimal digits.

   - gh-118473(6): Fix *note sys.set_asyncgen_hooks(): 1730. not to be
     partially set when raising *note TypeError: 2c3.

   - gh-118465(7): Compiler populates the new ‘__firstlineno__’ field on
     a class with the line number of the first line of the class
     definition.

   - gh-118492(8): Fix an issue where the type cache can expose a
     previously accessed attribute when a finalizer is run.

   - gh-117714(9): update ‘async_generator.athrow().close()’ and
     ‘async_generator.asend().close()’ to close their section of the
     underlying async generator

   - gh-111201(10): The *note interactive: 169. interpreter is now
     implemented in Python, which allows for a number of new features
     like colors, multiline input, history viewing, and paste mode.
     Contributed by Pablo Galindo, Łukasz Langa and Lysandros Nikolaou
     based on code from the PyPy project.

   - gh-74929(11): Implement PEP 667: converted *note
     FrameType.f_locals: 182. and *note PyFrame_GetLocals(): 422. to
     return a write-through proxy object when the frame refers to a
     function or comprehension.

   - gh-116767(12): Fix crash in compiler on ‘async with’ that has many
     context managers.

   - gh-118335(13): Change how to use the tier 2 interpreter.  Instead
     of running Python with ‘-X uops’ or setting the environment
     variable ‘PYTHON_UOPS=1’, this choice is now made at build time by
     configuring with ‘--enable-experimental-jit=interpreter’.

     'Beware!'  This changes the environment variable to enable or
     disable micro-ops to ‘PYTHON_JIT’.  The old ‘PYTHON_UOPS’ is no
     longer used.

   - gh-118306(14): Update JIT compilation to use LLVM 18

   - gh-118160(15): *note Annotation scopes: 188. within classes can now
     contain comprehensions.  However, such comprehensions are not
     inlined into their parent scope at runtime.  Patch by Jelle
     Zijlstra.

   - gh-118272(16): Fix bug where ‘generator.close’ does not free the
     generator frame’s locals.

   - gh-118216(17): Don’t consider *note __future__: 0. imports with
     dots before the module name.

   - gh-118074(18): Make sure that the Executor objects in the
     COLD_EXITS array aren’t assumed to be GC-able (which would access
     bytes outside the object).

   - gh-107674(19): Lazy load frame line number to improve performance
     of tracing

   - gh-118082(20): Improve *note SyntaxError: 18d. message for imports
     without names, like in ‘from x import’ and ‘import’ cases.  It now
     points out to users that *note import: 5e5. expects at least one
     name after it.

   - gh-118090(21): Improve *note SyntaxError: 18d. message for empty
     type param brackets.

   - gh-117958(22): Added a ‘get_jit_code()’ method to access JIT
     compiled machine code from the UOp Executor when the experimental
     JIT is enabled.  Patch by Anthony Shaw.

   - gh-117901(23): Add option for compiler’s codegen to save nested
     instruction sequences for introspection.

   - gh-116622(24): Redirect stdout and stderr to system log when
     embedded in an Android app.

   - gh-109118(25): *note annotation scope: 188. within class scopes can
     now contain lambdas.

   - gh-117894(26): Prevent ‘agen.aclose()’ objects being re-used after
     ‘.throw()’.

   - gh-117881(27): prevent concurrent access to an async generator via
     athrow().throw() or asend().throw()

   - gh-117536(28): Fix a *note RuntimeWarning: 1bd. when calling
     ‘agen.aclose().throw(Exception)’.

   - gh-117755(29): Fix mimalloc allocator for huge memory allocation
     (around 8,589,934,592 GiB) on s390x.  Patch by Victor Stinner.

   - gh-117750(30): Fix issue where an object’s dict would get out of
     sync with the object’s internal values when being cleared.
     ‘obj.__dict__.clear()’ now clears the internal values, but leaves
     the dict attached to the object.

   - gh-117431(31): Improve the performance of the following *note
     bytes: 1c2. and *note bytearray: 2ea. methods by adapting them to
     the *note METH_FASTCALL: 1731. calling convention:

        * ‘count()’

        * ‘find()’

        * ‘index()’

        * ‘rfind()’

        * ‘rindex()’

   - gh-117709(32): Speed up calls to *note str(): 44f. with
     positional-only argument, by using the PEP 590(33) ‘vectorcall’
     calling convention.  Patch by Erlend Aasland.

   - gh-117680(34): Give ‘_PyInstructionSequence’ a Python interface and
     use it in tests.

   - gh-115776(35): Statically allocated objects are, by definition,
     immortal so must be marked as such regardless of whether they are
     in extension modules or not.

   - gh-117385(36): Remove unhandled ‘PY_MONITORING_EVENT_BRANCH’ and
     ‘PY_MONITORING_EVENT_EXCEPTION_HANDLED’ events from *note
     sys.settrace(): 154e.

   - gh-116322(37): Extension modules may indicate to the runtime that
     they can run without the GIL. Multi-phase init modules do so by
     calling providing ‘Py_MOD_GIL_NOT_USED’ for the ‘Py_mod_gil’ slot,
     while single-phase init modules call ‘PyUnstable_Module_SetGIL(mod,
     Py_MOD_GIL_NOT_USED)’ from their init function.

   - gh-116129(38): Implement PEP 696(39), adding support for defaults
     on type parameters.  Patch by Jelle Zijlstra.

   - gh-93502(40): Add two new functions to the C-API, *note
     PyRefTracer_SetTracer(): 36f. and *note PyRefTracer_GetTracer():
     370, that allows to track object creation and destruction the same
     way the *note tracemalloc: ff. module does.  Patch by Pablo Galindo

   - gh-107674(41): Improved the performance of *note sys.settrace():
     154e. significantly

   - gh-95754(42): Improve the error message when a script shadowing a
     module from the standard library causes *note AttributeError: 34e.
     to be raised.  Similarly, improve the error message when a script
     shadowing a third party module attempts to access an attribute from
     that third party module while still initialising.

   - gh-99180(43): Elide uninformative traceback indicators in ‘return’
     and simple ‘assignment’ statements.  Patch by Pablo Galindo.

   - gh-105879(44): Allow the 'globals' and 'locals' arguments to *note
     exec(): 17f. and *note eval(): 180. to be passed as keywords.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116322

   (2) https://github.com/python/cpython/issues/118513

   (3) https://github.com/python/cpython/issues/118518

   (4) https://github.com/python/cpython/issues/117514

   (5) https://github.com/python/cpython/issues/118164

   (6) https://github.com/python/cpython/issues/118473

   (7) https://github.com/python/cpython/issues/118465

   (8) https://github.com/python/cpython/issues/118492

   (9) https://github.com/python/cpython/issues/117714

   (10) https://github.com/python/cpython/issues/111201

   (11) https://github.com/python/cpython/issues/74929

   (12) https://github.com/python/cpython/issues/116767

   (13) https://github.com/python/cpython/issues/118335

   (14) https://github.com/python/cpython/issues/118306

   (15) https://github.com/python/cpython/issues/118160

   (16) https://github.com/python/cpython/issues/118272

   (17) https://github.com/python/cpython/issues/118216

   (18) https://github.com/python/cpython/issues/118074

   (19) https://github.com/python/cpython/issues/107674

   (20) https://github.com/python/cpython/issues/118082

   (21) https://github.com/python/cpython/issues/118090

   (22) https://github.com/python/cpython/issues/117958

   (23) https://github.com/python/cpython/issues/117901

   (24) https://github.com/python/cpython/issues/116622

   (25) https://github.com/python/cpython/issues/109118

   (26) https://github.com/python/cpython/issues/117894

   (27) https://github.com/python/cpython/issues/117881

   (28) https://github.com/python/cpython/issues/117536

   (29) https://github.com/python/cpython/issues/117755

   (30) https://github.com/python/cpython/issues/117750

   (31) https://github.com/python/cpython/issues/117431

   (32) https://github.com/python/cpython/issues/117709

   (33) https://peps.python.org/pep-0590/

   (34) https://github.com/python/cpython/issues/117680

   (35) https://github.com/python/cpython/issues/115776

   (36) https://github.com/python/cpython/issues/117385

   (37) https://github.com/python/cpython/issues/116322

   (38) https://github.com/python/cpython/issues/116129

   (39) https://peps.python.org/pep-0696/

   (40) https://github.com/python/cpython/issues/93502

   (41) https://github.com/python/cpython/issues/107674

   (42) https://github.com/python/cpython/issues/95754

   (43) https://github.com/python/cpython/issues/99180

   (44) https://github.com/python/cpython/issues/105879


File: python.info,  Node: Library<30>,  Next: Documentation<13>,  Prev: Core and Builtins<26>,  Up: Python 3 13 0 beta 1

1.23.21.5 Library
.................

   - gh-118418(1): A *note DeprecationWarning: 1a5. is now emitted if
     you fail to pass a value to the new 'type_params' parameter of
     ‘typing._eval_type()’ or ‘typing.ForwardRef._evaluate()’.  (Using
     either of these private and undocumented functions is discouraged
     to begin with, but failing to pass a value to the ‘type_params’
     parameter may lead to incorrect behaviour on Python 3.12 or newer.)

   - gh-118660(2): Add an optional second type parameter to *note
     typing.ContextManager: cb2. and *note typing.AsyncContextManager:
     1733, representing the return types of *note __exit__(): 1349. and
     *note __aexit__(): 1734. respectively.  This parameter defaults to
     ‘bool | None’.

   - gh-118650(3): The ‘enum’ module allows method named ‘_repr_*’ to be
     defined on ‘Enum’ types.

   - gh-118648(4): Add type parameter defaults to *note
     typing.Generator: 1735. and *note typing.AsyncGenerator: 1736.

   - gh-101137(5): Mime type ‘text/x-rst’ is now supported by *note
     mimetypes: 8f.

   - gh-118164(6): The Python implementation of the ‘decimal’ module
     could appear to hang in relatively small power cases (like
     ‘2**117’) if context precision was set to a very high value.  A
     different method to check for exactly representable results is used
     now that doesn’t rely on computing ‘10**precision’ (which could be
     effectively too large to compute).

   - gh-111744(7): ‘breakpoint()’ and ‘pdb.set_trace()’ now enter the
     debugger immediately after the call rather than before the next
     line is executed.

   - gh-118500(8): Add *note pdb: a5. support for zipapps

   - gh-118406(9): Add signature for *note sqlite3.Connection: 245.
     objects.

   - gh-101732(10): Use a Y2038 compatible openssl time function when
     available.

   - gh-118404(11): Fix *note inspect.signature(): 73b. for
     non-comparable callables.

   - gh-118402(12): Fix *note inspect.signature(): 73b. for the result
     of the *note functools.cmp_to_key(): 121f. call.

   - gh-116622(13): On Android, *note sysconfig.get_platform: 1288. now
     returns the format specified by PEP 738(14).

   - gh-118285(15): Allow to specify the signature of custom callable
     instances of extension type by the ‘__text_signature__’ attribute.
     Specify signatures of *note operator.attrgetter: e66, *note
     operator.itemgetter: a70, and *note operator.methodcaller: e67.
     instances.

   - gh-118314(16): Fix an edge case in *note binascii.a2b_base64():
     15ae. strict mode, where excessive padding is not detected when no
     padding is necessary.

   - gh-118271(17): Add the ‘PhotoImage’ methods ‘read()’ to read an
     image from a file and ‘data()’ to get the image data.  Add
     'background' and 'grayscale' parameters to ‘PhotoImage’ method
     ‘write()’.

   - gh-118225(18): Add the ‘PhotoImage’ method ‘copy_replace()’ to copy
     a region from one image to other image, possibly with pixel zooming
     and/or subsampling.  Add 'from_coords' parameter to ‘PhotoImage’
     methods ‘copy()’, ‘zoom()’ and ‘subsample()’.  Add 'zoom' and
     'subsample' parameters to ‘PhotoImage’ method ‘copy()’.

   - gh-118221(19): Fix a bug where *note sqlite3.Connection.iterdump():
     247. could fail if a custom *note row factory: 1737. was used.
     Patch by Erlend Aasland.

   - gh-118013(20): Fix regression introduced in gh-103193(21) that
     meant that calling *note inspect.getattr_static(): 497. on an
     instance would cause a strong reference to that instance’s class to
     persist in an internal cache in the *note inspect: 7e. module.
     This caused unexpected memory consumption if the class was
     dynamically created, the class held strong references to other
     objects which took up a significant amount of memory, and the cache
     contained the sole strong reference to the class.  The fix for the
     regression leads to a slowdown in ‘getattr_static()’, but the
     function should still be significantly faster than it was in Python
     3.11.  Patch by Alex Waygood.

   - gh-118218(22): Speed up *note itertools.pairwise(): 81b. in the
     common case by up to 1.8x.

   - gh-117486(23): Improve the behavior of user-defined subclasses of
     *note ast.AST: 1a6.  Such classes will now require no changes in
     the usual case to conform with the behavior changes of the *note
     ast: 8. module in Python 3.13.  Patch by Jelle Zijlstra.

   - gh-90848(24): Fixed *note unittest.mock.create_autospec(): 1712. to
     configure parent mock with keyword arguments.

   - gh-118168(25): Fix incorrect argument substitution when *note
     typing.Unpack: 1738. is used with the builtin *note tuple: 373.
     ‘typing.Unpack’ now raises *note TypeError: 2c3. when used with
     certain invalid types.  Patch by Jelle Zijlstra.

   - gh-118131(26): Add command-line interface for the *note random: b8.
     module.  Patch by Hugo van Kemenade.

   - gh-118107(27): Fix *note zipimport: 132. reading of ZIP64 files
     with file entries that are too big or offset too far.

   - gh-102511(28): Fix *note os.path.normpath(): 1363. for UNC paths on
     Windows.  Speed up *note os.path.splitroot(): 4a7. with a native
     implementation.

   - gh-117535(29): Change the unknown filename of *note warnings: 112.
     from ‘sys’ to ‘<sys>’ to clarify that it’s not a real filename.

   - gh-114053(30): Fix erroneous *note NameError: 442. when calling
     *note typing.get_type_hints(): 6b4. on a class that made use of PEP
     695(31) type parameters in a module that had ‘from __future__
     import annotations’ at the top of the file.  Patch by Alex Waygood.

   - gh-116931(32): Add parameter 'fileobj' check for *note
     tarfile.TarFile.addfile(): 1739.

   - gh-117995(33): Don’t raise *note DeprecationWarning: 1a5. when a
     *note sequence: 4f4. of parameters is used to bind indexed,
     nameless placeholders.  See also gh-100668(34).

   - gh-80361(35): Fix TypeError in *note
     email.message.Message.get_payload(): 1212. when the charset is RFC
     2231(36) encoded.

   - gh-86650(37): Fix IndexError when parse some emails with invalid
     Message-ID (including one-off addresses generated by Microsoft
     Outlook).

   - gh-117691(38): Improve the error messages emitted by *note tarfile:
     de. deprecation warnings relating to PEP 706.  If a ‘filter’
     argument is not provided to ‘extract()’ or ‘extractall’, the
     deprecation warning now points to the line in the user’s code where
     the relevant function was called.  Patch by Alex Waygood.

   - gh-115874(39): Fixed a possible segfault during garbage collection
     of ‘_asyncio.FutureIter’ objects.  Patch by Savannah Ostrowski.

   - gh-115060(40): Speed up *note pathlib.Path.glob(): 22d. by omitting
     an initial *note is_dir(): 230. call.  As a result of this change,
     ‘glob()’ can no longer raise *note OSError: 41a.

   - gh-77102(41): *note site: c7. module now parses ‘.pth’ file with
     UTF-8 first, and *note locale encoding: 242. if
     ‘UnicodeDecodeError’ happened.  It supported only locale encoding
     before.

   - gh-76785(42): We’ve exposed the low-level ‘_interpreters’ module
     for the sake of the PyPI implementation of PEP 734(43).  It was
     sometimes available as the ‘_xxsubinterpreters’ module and was
     formerly used only for testing.  For the most part, it should be
     considered an internal module, like ‘_thread’ and ‘_imp’.  See
     ‘https://discuss.python.org/t/pep-734-multiple-interpreters-in-the-stdlib/41147/26’.

   - gh-115060(44): Speed up *note pathlib.Path.glob(): 22d. by not
     scanning directories for non-wildcard pattern segments.

   - gh-117727(45): Speed up *note pathlib.Path.iterdir(): 173a. by
     using *note os.scandir(): a6d. internally.

   - gh-117586(46): Speed up *note pathlib.Path.walk(): 4ab. by working
     with strings internally.

   - gh-117722(47): Change the new multi-separator support in *note
     asyncio.StreamReader.readuntil(): 1b4. to only accept tuples of
     separators rather than arbitrary iterables.

   - gh-117692(48): Fixes a bug when *note doctest.DocTestFinder: 173b.
     was failing on wrapped ‘builtin_function_or_method’.

   - gh-117348(49): Largely restored import time performance of
     configparser by avoiding dataclasses.

   - gh-117641(50): Speedup *note os.path.commonpath(): e70. on Unix.

   - gh-117663(51): Fix ‘_simple_enum’ to detect aliases when multiple
     arguments are present but only one is the member value.

   - gh-117636(52): Speedup *note os.path.join(): 173c.

   - gh-117618(53): Support ‘package.module’ as ‘filename’ for ‘break’
     command of *note pdb: a5.

   - gh-102247(54): the status codes enum with constants in
     http.HTTPStatus are updated to include the names from RFC9110.
     This RFC includes some HTTP statuses previously only used for
     WEBDAV and assigns more generic names to them.

     The old constants are preserved for backwards compatibility.

   - gh-117607(55): Speedup *note os.path.relpath(): 4ad.

   - gh-117586(56): Speed up *note pathlib.Path.glob(): 22d. by working
     with strings internally.

   - gh-117225(57): Add colour to doctest output.  Patch by Hugo van
     Kemenade.

   - gh-117566(58): *note ipaddress.IPv6Address.is_loopback(): 173d.
     will now return ‘True’ for IPv4-mapped loopback addresses, i.e.
     addresses in the ‘::ffff:127.0.0.0/104’ address space.

   - gh-117546(59): Fix issue where *note os.path.realpath(): 225.
     stopped resolving symlinks after encountering a symlink loop on
     POSIX.

   - gh-116720(60): Improved behavior of *note asyncio.TaskGroup: 1b5.
     when an external cancellation collides with an internal
     cancellation.  For example, when two task groups are nested and
     both experience an exception in a child task simultaneously, it was
     possible that the outer task group would misbehave, because its
     internal cancellation was swallowed by the inner task group.

     In the case where a task group is cancelled externally and also
     must raise an *note ExceptionGroup: 1b6, it will now call the
     parent task’s *note cancel(): 1b7. method.  This ensures that a
     *note asyncio.CancelledError: 1b8. will be raised at the next *note
     await: 1b9, so the cancellation is not lost.

     An added benefit of these changes is that task groups now preserve
     the cancellation count (*note asyncio.Task.cancelling(): 1ba.).

     In order to handle some corner cases, *note
     asyncio.Task.uncancel(): 1bb. may now reset the undocumented
     ‘_must_cancel’ flag when the cancellation count reaches zero.

   - gh-117516(61): Add *note typing.TypeIs: 163, implementing PEP
     742(62).  Patch by Jelle Zijlstra.

   - gh-117503(63): Fix support of non-ASCII user names in bytes paths
     in *note os.path.expanduser(): a21. on Posix.

   - gh-117394(64): *note os.path.ismount(): a1f. is now 2-3 times
     faster if the user has permissions.

   - gh-117313(65): Only treat ‘'\n'’, ‘'\r'’ and ‘'\r\n'’ as line
     separators in re-folding the *note email: 3b. messages.  Preserve
     control characters ‘'\v'’, ‘'\f'’, ‘'\x1c'’, ‘'\x1d'’ and ‘'\x1e'’
     and Unicode line separators ‘'\x85'’, ‘'\u2028'’ and ‘'\u2029'’ as
     is.

   - gh-117142(66): Convert ‘_ctypes’ to multi-phase initialisation (
     PEP 489(67)).

   - gh-66543(68): Add the *note mimetypes.guess_file_type(): 207.
     function which works with file path.  Passing file path instead of
     URL in *note guess_type(): 208. is *note soft deprecated: 209.

   - gh-68583(69): webbrowser CLI: replace getopt with argparse, add
     long options.  Patch by Hugo van Kemenade.

   - gh-116871(70): Name suggestions for *note AttributeError: 34e. and
     *note ImportError: 41c. now only include underscored names if the
     original name was underscored.

   - gh-116023(71): Don’t show empty fields (value ‘None’ or ‘[]’) in
     *note ast.dump(): 8ed. by default.  Add ‘show_empty=False’
     parameter to optionally show them.

   - gh-115961(72): Added ‘name’ and ‘mode’ attributes for compressed
     and archived file-like objects in modules *note bz2: 13, *note
     lzma: 8a, *note tarfile: de. and *note zipfile: 131.  The value of
     the ‘mode’ attribute of *note gzip.GzipFile: 41d. was changed from
     integer (‘1’ or ‘2’) to string (‘'rb'’ or ‘'wb'’).  The value of
     the ‘mode’ attribute of the readable file-like object returned by
     *note zipfile.ZipFile.open(): 41e. was changed from ‘'r'’ to
     ‘'rb'’.

   - gh-82062(73): Fix *note inspect.signature(): 73b. to correctly
     handle parameter defaults on methods in extension modules that use
     names defined in the module namespace.

   - gh-83856(74): Honor *note atexit: c. for all *note multiprocessing:
     94. start methods

   - gh-113081(75): Print colorized exception just like built-in
     traceback in *note pdb: a5.

   - gh-112855(76): Speed up pickling of *note pathlib.PurePath: 4a9.
     objects.  Patch by Barney Gale.

   - gh-111744(77): Support opcode events in *note bdb: f.

   - gh-109617(78): ‘ncurses’: fixed a crash that could occur on macOS
     13 or earlier when Python was built with Apple Xcode 15’s SDK.

   - gh-83151(79): Enabled arbitrary statements and evaluations in *note
     pdb: a5. shell to access the local variables of the current frame,
     which made it possible for multi-scope code like generators or
     nested function to work.

   - gh-110209(80): Add *note __class_getitem__(): 73e. to *note
     types.GeneratorType: 173e. and *note types.CoroutineType: ebd. for
     type hinting purposes.  Patch by James Hilton-Balfe.

   - gh-108191(81): The *note types.SimpleNamespace: 1d1. now accepts an
     optional positional argument which specifies initial values of
     attributes as a dict or an iterable of key-value pairs.

   - gh-62090(82): Fix assertion errors caused by whitespace in metavars
     or ‘SUPPRESS’-ed groups in *note argparse: 6. by simplifying usage
     formatting.  Patch by Ali Hamdan.

   - gh-102402(83): Adjust ‘logging.LogRecord’ to use ‘time.time_ns()’
     and fix minor bug related to floating-point math.

   - gh-100242(84): Bring pure Python implementation
     ‘functools.partial.__new__’ more in line with the C-implementation
     by not just always checking for the presence of the attribute
     ‘'func'’ on the first argument of ‘partial’.  Instead, both the
     Python version and the C version perform an ‘isinstance(func,
     partial)’ check on the first argument of ‘partial’.

   - gh-99730(85): HEAD requests are no longer upgraded to GET request
     during redirects in urllib.

   - gh-66410(86): Setting the ‘tkinter’ module global ‘wantobjects’ to
     ‘2’ before creating the *note Tk: 173f. object or call the
     ‘wantobjects()’ method of the ‘Tk’ object with argument ‘2’ makes
     now arguments to callbacks registered in the *note tkinter: f0.
     module to be passed as various Python objects (‘int’, ‘float’,
     ‘bytes’, ‘tuple’), depending on their internal representation in
     Tcl, instead of always ‘str’.  ‘tkinter.wantobjects’ is now set to
     ‘2’ by default.

   - bpo-40943(87): Fix several IndexError when parse emails with
     truncated Message-ID, address, routes, etc, e.g.  ‘example@’.

   - bpo-39324(88): Add mime type mapping for .md <-> text/markdown

   - bpo-18108(89): *note shutil.chown(): 240. now supports 'dir_fd' and
     'follow_symlinks' keyword arguments.

   - bpo-30988(90): Fix parsing of emails with invalid address headers
     having a leading or trailing dot.  Patch by tsufeki.

   - bpo-32839(91): Add the ‘after_info()’ method for Tkinter widgets.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118418

   (2) https://github.com/python/cpython/issues/118660

   (3) https://github.com/python/cpython/issues/118650

   (4) https://github.com/python/cpython/issues/118648

   (5) https://github.com/python/cpython/issues/101137

   (6) https://github.com/python/cpython/issues/118164

   (7) https://github.com/python/cpython/issues/111744

   (8) https://github.com/python/cpython/issues/118500

   (9) https://github.com/python/cpython/issues/118406

   (10) https://github.com/python/cpython/issues/101732

   (11) https://github.com/python/cpython/issues/118404

   (12) https://github.com/python/cpython/issues/118402

   (13) https://github.com/python/cpython/issues/116622

   (14) https://peps.python.org/pep-0738/

   (15) https://github.com/python/cpython/issues/118285

   (16) https://github.com/python/cpython/issues/118314

   (17) https://github.com/python/cpython/issues/118271

   (18) https://github.com/python/cpython/issues/118225

   (19) https://github.com/python/cpython/issues/118221

   (20) https://github.com/python/cpython/issues/118013

   (21) https://github.com/python/cpython/issues/103193

   (22) https://github.com/python/cpython/issues/118218

   (23) https://github.com/python/cpython/issues/117486

   (24) https://github.com/python/cpython/issues/90848

   (25) https://github.com/python/cpython/issues/118168

   (26) https://github.com/python/cpython/issues/118131

   (27) https://github.com/python/cpython/issues/118107

   (28) https://github.com/python/cpython/issues/102511

   (29) https://github.com/python/cpython/issues/117535

   (30) https://github.com/python/cpython/issues/114053

   (31) https://peps.python.org/pep-0695/

   (32) https://github.com/python/cpython/issues/116931

   (33) https://github.com/python/cpython/issues/117995

   (34) https://github.com/python/cpython/issues/100668

   (35) https://github.com/python/cpython/issues/80361

   (36) https://datatracker.ietf.org/doc/html/rfc2231.html

   (37) https://github.com/python/cpython/issues/86650

   (38) https://github.com/python/cpython/issues/117691

   (39) https://github.com/python/cpython/issues/115874

   (40) https://github.com/python/cpython/issues/115060

   (41) https://github.com/python/cpython/issues/77102

   (42) https://github.com/python/cpython/issues/76785

   (43) https://peps.python.org/pep-0734/

   (44) https://github.com/python/cpython/issues/115060

   (45) https://github.com/python/cpython/issues/117727

   (46) https://github.com/python/cpython/issues/117586

   (47) https://github.com/python/cpython/issues/117722

   (48) https://github.com/python/cpython/issues/117692

   (49) https://github.com/python/cpython/issues/117348

   (50) https://github.com/python/cpython/issues/117641

   (51) https://github.com/python/cpython/issues/117663

   (52) https://github.com/python/cpython/issues/117636

   (53) https://github.com/python/cpython/issues/117618

   (54) https://github.com/python/cpython/issues/102247

   (55) https://github.com/python/cpython/issues/117607

   (56) https://github.com/python/cpython/issues/117586

   (57) https://github.com/python/cpython/issues/117225

   (58) https://github.com/python/cpython/issues/117566

   (59) https://github.com/python/cpython/issues/117546

   (60) https://github.com/python/cpython/issues/116720

   (61) https://github.com/python/cpython/issues/117516

   (62) https://peps.python.org/pep-0742/

   (63) https://github.com/python/cpython/issues/117503

   (64) https://github.com/python/cpython/issues/117394

   (65) https://github.com/python/cpython/issues/117313

   (66) https://github.com/python/cpython/issues/117142

   (67) https://peps.python.org/pep-0489/

   (68) https://github.com/python/cpython/issues/66543

   (69) https://github.com/python/cpython/issues/68583

   (70) https://github.com/python/cpython/issues/116871

   (71) https://github.com/python/cpython/issues/116023

   (72) https://github.com/python/cpython/issues/115961

   (73) https://github.com/python/cpython/issues/82062

   (74) https://github.com/python/cpython/issues/83856

   (75) https://github.com/python/cpython/issues/113081

   (76) https://github.com/python/cpython/issues/112855

   (77) https://github.com/python/cpython/issues/111744

   (78) https://github.com/python/cpython/issues/109617

   (79) https://github.com/python/cpython/issues/83151

   (80) https://github.com/python/cpython/issues/110209

   (81) https://github.com/python/cpython/issues/108191

   (82) https://github.com/python/cpython/issues/62090

   (83) https://github.com/python/cpython/issues/102402

   (84) https://github.com/python/cpython/issues/100242

   (85) https://github.com/python/cpython/issues/99730

   (86) https://github.com/python/cpython/issues/66410

   (87) https://bugs.python.org/issue?@action=redirect&bpo=40943

   (88) https://bugs.python.org/issue?@action=redirect&bpo=39324

   (89) https://bugs.python.org/issue?@action=redirect&bpo=18108

   (90) https://bugs.python.org/issue?@action=redirect&bpo=30988

   (91) https://bugs.python.org/issue?@action=redirect&bpo=32839


File: python.info,  Node: Documentation<13>,  Next: Build<15>,  Prev: Library<30>,  Up: Python 3 13 0 beta 1

1.23.21.6 Documentation
.......................

   - gh-117928(1): The minimum Sphinx version required for the
     documentation is now 6.2.1.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117928


File: python.info,  Node: Build<15>,  Next: Windows<13>,  Prev: Documentation<13>,  Up: Python 3 13 0 beta 1

1.23.21.7 Build
...............

   - gh-118734(1): Fixes Windows build when invoked directly (not
     through the ‘build.bat’ script) without specifying a value for
     ‘UseTIER2’.

   - gh-115119(2): The ‘configure’ option *note -with-system-libmpdec:
     415. now defaults to ‘yes’.  The bundled copy of ‘libmpdecimal’
     will be removed in Python 3.15.

   - gh-117845(3): Fix building against recent libedit versions by
     detecting readline hook signatures in ‘configure’.

   - gh-116622(4): A testbed project was added to run the test suite on
     Android.

   - gh-117645(5): Increase WASI stack size from 512 KiB to 8 MiB and
     the initial memory from 10 MiB to 20 MiB. Patch by Victor Stinner.

   - gh-115119(6): ‘configure’ now uses ‘pkg-config’ to detect *note
     decimal: 36. dependencies if the *note -with-system-libmpdec: 415.
     option is given.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118734

   (2) https://github.com/python/cpython/issues/115119

   (3) https://github.com/python/cpython/issues/117845

   (4) https://github.com/python/cpython/issues/116622

   (5) https://github.com/python/cpython/issues/117645

   (6) https://github.com/python/cpython/issues/115119


File: python.info,  Node: Windows<13>,  Next: macOS<9>,  Prev: Build<15>,  Up: Python 3 13 0 beta 1

1.23.21.8 Windows
.................

   - gh-115119(1): Update Windows installer to use libmpdecimal 4.0.0.

   - gh-118486(2): *note os.mkdir(): 21d. now accepts 'mode' of ‘0o700’
     to restrict the new directory to the current user.

   - gh-118347(3): Fixes launcher updates not being installed.

   - gh-118293(4): The ‘multiprocessing’ module now passes the
     ‘STARTF_FORCEOFFFEEDBACK’ flag when spawning processes to tell
     Windows not to change the mouse cursor.

   - gh-115009(5): Update Windows installer to use SQLite 3.45.3.

   - gh-90329(6): Suppress the warning displayed on virtual environment
     creation when the requested and created paths differ only by a
     short (8.3 style) name.  Warnings will continue to be shown if a
     junction or symlink in the path caused the venv to be created in a
     different location than originally requested.

   - gh-117786(7): Fixes virtual environments not correctly launching
     when created from a Store install.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115119

   (2) https://github.com/python/cpython/issues/118486

   (3) https://github.com/python/cpython/issues/118347

   (4) https://github.com/python/cpython/issues/118293

   (5) https://github.com/python/cpython/issues/115009

   (6) https://github.com/python/cpython/issues/90329

   (7) https://github.com/python/cpython/issues/117786


File: python.info,  Node: macOS<9>,  Next: IDLE<12>,  Prev: Windows<13>,  Up: Python 3 13 0 beta 1

1.23.21.9 macOS
...............

   - gh-115119(1): Update macOS installer to use libmpdecimal 4.0.0.

   - gh-114099(2): iOS preprocessor symbol usage was made compatible
     with older macOS SDKs.

   - gh-115009(3): Update macOS installer to use SQLite 3.45.3.

   - gh-91629(4): Use ‘~/.config/fish/conf.d’ configs and
     ‘fish_add_path’ to set ‘PATH’ when installing for the Fish shell.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115119

   (2) https://github.com/python/cpython/issues/114099

   (3) https://github.com/python/cpython/issues/115009

   (4) https://github.com/python/cpython/issues/91629


File: python.info,  Node: IDLE<12>,  Next: C API<15>,  Prev: macOS<9>,  Up: Python 3 13 0 beta 1

1.23.21.10 IDLE
...............

   - bpo-34774(1): Use user-selected color theme for Help => IDLE Doc.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34774


File: python.info,  Node: C API<15>,  Prev: IDLE<12>,  Up: Python 3 13 0 beta 1

1.23.21.11 C API
................

   - gh-118124(1): Fix *note Py_BUILD_ASSERT: 1746. and *note
     Py_BUILD_ASSERT_EXPR: 1747. for non-constant expressions: use
     ‘static_assert()’ on C11 and newer.  Patch by Victor Stinner.

   - gh-110850(2): Add “Raw” variant of PyTime functions

        * *note PyTime_MonotonicRaw(): 333.

        * *note PyTime_PerfCounterRaw(): 335.

        * *note PyTime_TimeRaw(): 337.

     Patch by Victor Stinner.

   - gh-117987(3): Restore functions removed in Python 3.13 alpha 1:

        * *note Py_SetPythonHome(): 1748.

        * *note Py_SetProgramName(): 1749.

        * *note PySys_SetArgvEx(): 174a.

        * *note PySys_SetArgv(): 174b.

     Patch by Victor Stinner.

   - gh-117929(4): Restore removed *note PyEval_InitThreads(): 174c.
     function.  Patch by Victor Stinner.

   - gh-117534(5): Improve validation logic in the C implementation of
     *note datetime.datetime.fromisoformat(): 61a. to better handle
     invalid years.  Patch by Vlad Efanov.

   - gh-68114(6): Fixed skipitem()’s handling of the old ‘w’ and ‘w#’
     formatters.  These are no longer supported and now raise an
     exception if used.

   - gh-111997(7): Add a C-API for firing monitoring events.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/118124

   (2) https://github.com/python/cpython/issues/110850

   (3) https://github.com/python/cpython/issues/117987

   (4) https://github.com/python/cpython/issues/117929

   (5) https://github.com/python/cpython/issues/117534

   (6) https://github.com/python/cpython/issues/68114

   (7) https://github.com/python/cpython/issues/111997


File: python.info,  Node: Python 3 13 0 alpha 6,  Next: Python 3 13 0 alpha 5,  Prev: Python 3 13 0 beta 1,  Up: Changelog

1.23.22 Python 3.13.0 alpha 6
-----------------------------

'Release date: 2024-04-09'

* Menu:

* Core and Builtins: Core and Builtins<27>.
* Library: Library<31>.
* Core and Builtins: Core and Builtins<28>.
* Library: Library<32>.
* Documentation: Documentation<14>.
* Tests: Tests<16>.
* Build: Build<16>.
* Windows: Windows<14>.
* C API: C API<16>.


File: python.info,  Node: Core and Builtins<27>,  Next: Library<31>,  Up: Python 3 13 0 alpha 6

1.23.22.1 Core and Builtins
...........................

   - gh-117494(1): Refactored the instruction sequence data structure
     out of compile.c into instruction_sequence.c.

   - gh-116968(2): Introduce a unified 16-bit backoff counter type
     (‘_Py_BackoffCounter’), shared between the Tier 1 adaptive
     specializer and the Tier 2 optimizer.  The API used for adaptive
     specialization counters is changed but the behavior is (supposed to
     be) identical.

     The behavior of the Tier 2 counters is changed:

        * There are no longer dynamic thresholds (we never varied
          these).

        * All counters now use the same exponential backoff.

        * The counter for ‘JUMP_BACKWARD’ starts counting down from 16.

        * The ‘temperature’ in side exits starts counting down from 64.

   - gh-117431(3): Improve the performance of the following *note bytes:
     1c2. and *note bytearray: 2ea. methods by adapting them to the
     *note METH_FASTCALL: 1731. calling convention:

        * ‘endswith()’

        * ‘startswith()’

   - gh-117431(4): Improve the performance of the following *note str:
     44f. methods by adapting them to the *note METH_FASTCALL: 1731.
     calling convention:

        * *note count(): 174f.

        * *note endswith(): f00.

        * *note find(): edc.

        * *note index(): 1750.

        * *note rfind(): edd.

        * *note rindex(): 129e.

        * *note startswith(): eff.

   - gh-117411(5): Move ‘PyFutureFeatures’ to an internal header and
     make it private.

   - gh-109120(6): Added handle of incorrect star expressions, e.g ‘f(3,
     *)’.  Patch by Grigoryev Semyon

   - gh-117266(7): Fix crashes for certain user-created subclasses of
     *note ast.AST: 1a6.  Such classes are now expected to set the
     ‘_field_types’ attribute.

   - gh-99108(8): Updated the *note hashlib: 68. built-in HACL*
     project(9) C code from upstream that we use for many
     implementations when they are not present via OpenSSL in a given
     build.  This also avoids the rare potential for a C symbol name one
     definition rule linking issue.

   - gh-117108(10): Change the old space bit of objects in the young
     generation from 0 to gcstate->visited, so that any objects created
     during GC will have the old bit set correctly if they get moved
     into the old generation.

   - gh-117108(11): The cycle GC now chooses the size of increments
     based on the total heap size, instead of the rate of object
     creation.  This ensures that it can keep up with growing heaps.

   - gh-116735(12): For ‘INSTRUMENTED_CALL_FUNCTION_EX’, set ‘arg0’ to
     ‘sys.monitoring.MISSING’ instead of ‘None’ for *note CALL: 1751.
     event.

   - gh-113964(13): Starting new threads and process creation through
     *note os.fork(): 197. are now only prevented once all non-daemon
     threads exit.

   - gh-116626(14): Ensure ‘INSTRUMENTED_CALL_FUNCTION_EX’ always emits
     *note CALL: 1751.

   - gh-116554(15): ‘list.sort()’ now exploits more cases of partial
     ordering, particularly those with long descending runs with
     sub-runs of equal values.  Those are recognized as single runs now
     (previously, each block of repeated values caused a new run to be
     created).

   - gh-114099(16): Added a Loader that can discover extension modules
     in an iOS-style Frameworks folder.

   - gh-115775(17): Compiler populates the new ‘__static_attributes__’
     field on a class with the names of attributes of this class which
     are accessed through self.X from any function in its body.

   - gh-115776(18): The array of values, the ‘PyDictValues’ struct is
     now embedded in the object during allocation.  This provides better
     performance in the common case, and does not degrade as much when
     the object’s ‘__dict__’ is materialized.

   - gh-108362(19): Implement an incremental cyclic garbage collector.
     By collecting the old generation in increments, there is no need
     for a full heap scan.  This can hugely reduce maximum pause time
     for programs with large heaps.

     Reduce the number of generations from three to two.  The old
     generation is split into two spaces, “visited” and “pending”.

     Collection happens in two steps:: * An increment is formed from the
     young generation and a small part of the pending space.  * This
     increment is scanned and the survivors moved to the end of the
     visited space.

     When the collecting space becomes empty, the two spaces are
     swapped.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117494

   (2) https://github.com/python/cpython/issues/116968

   (3) https://github.com/python/cpython/issues/117431

   (4) https://github.com/python/cpython/issues/117431

   (5) https://github.com/python/cpython/issues/117411

   (6) https://github.com/python/cpython/issues/109120

   (7) https://github.com/python/cpython/issues/117266

   (8) https://github.com/python/cpython/issues/99108

   (9) https://github.com/hacl-star/hacl-star

   (10) https://github.com/python/cpython/issues/117108

   (11) https://github.com/python/cpython/issues/117108

   (12) https://github.com/python/cpython/issues/116735

   (13) https://github.com/python/cpython/issues/113964

   (14) https://github.com/python/cpython/issues/116626

   (15) https://github.com/python/cpython/issues/116554

   (16) https://github.com/python/cpython/issues/114099

   (17) https://github.com/python/cpython/issues/115775

   (18) https://github.com/python/cpython/issues/115776

   (19) https://github.com/python/cpython/issues/108362


File: python.info,  Node: Library<31>,  Next: Core and Builtins<28>,  Prev: Core and Builtins<27>,  Up: Python 3 13 0 alpha 6

1.23.22.2 Library
.................

   - gh-109870(1): Dataclasses now calls *note exec(): 17f. once per
     dataclass, instead of once per method being added.  This can speed
     up dataclass creation by up to 20%.

   - gh-97901(2): Mime type ‘text/rtf’ is now supported by *note
     mimetypes: 8f.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109870

   (2) https://github.com/python/cpython/issues/97901


File: python.info,  Node: Core and Builtins<28>,  Next: Library<32>,  Prev: Library<31>,  Up: Python 3 13 0 alpha 6

1.23.22.3 Core and Builtins
...........................

   - bpo-24612(1): Improve the *note SyntaxError: 18d. that happens when
     ‘not’ appears after an operator.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24612


File: python.info,  Node: Library<32>,  Next: Documentation<14>,  Prev: Core and Builtins<28>,  Up: Python 3 13 0 alpha 6

1.23.22.4 Library
.................

   - gh-117648(1): Improve performance of *note os.path.join(): 173c.
     and *note os.path.expanduser(): a21.

   - gh-117584(2): Raise *note TypeError: 2c3. for non-paths in *note
     posixpath.relpath: 4ad.

   - gh-117467(3): Preserve mailbox ownership when rewriting in *note
     mailbox.mbox.flush: 1755.  Patch by Tony Mountifield.

   - gh-114848(4): Raise *note FileNotFoundError: 42e. when ‘getcwd()’
     returns ‘(unreachable)’, which can happen on Linux >= 2.6.36 with
     glibc < 2.27.

   - gh-117459(5): ‘asyncio.asyncio.run_coroutine_threadsafe()’ now
     keeps the traceback of ‘CancelledError’, *note TimeoutError: 83b.
     and ‘InvalidStateError’ which are raised in the coroutine.

   - gh-117381(6): Fix error message for ‘ntpath.commonpath()’.

   - gh-117337(7): Deprecate undocumented ‘glob.glob0()’ and
     ‘glob.glob1()’ functions.  Use *note glob.glob(): 29f. and pass a
     directory to its 'root_dir' argument instead.

   - gh-117349(8): Optimise several functions in *note os.path: a2.

   - gh-117348(9): Refactored ‘configparser.RawConfigParser._read()’ to
     reduce cyclometric complexity and improve comprehensibility.

   - gh-117335(10): Raise TypeError for non-sequences for
     ‘ntpath.commonpath()’.

   - gh-66449(11): *note configparser.ConfigParser: 1c8. now accepts
     unnamed sections before named ones, if configured to do so.

   - gh-88014(12): In documentation of *note gzip.GzipFile: 41d. in
     module gzip, explain data type of optional constructor argument
     'mtime', and recommend ‘mtime = 0’ for generating deterministic
     streams.

   - gh-117310(13): Fixed an unlikely early & extra ‘Py_DECREF’
     triggered crash in *note ssl: d0. when creating a new
     ‘_ssl._SSLContext’ if CPython was built implausibly such that the
     default cipher list is empty 'or' the SSL library it was linked
     against reports a failure from its C ‘SSL_CTX_set_cipher_list()’
     API.

   - gh-117294(14): A ‘DocTestCase’ now reports as skipped if all
     examples in the doctest are skipped.

   - gh-98966(15): In *note subprocess: d6, raise a more informative
     message when ‘stdout=STDOUT’.

   - gh-117225(16): doctest: only print “and X failed” when non-zero,
     don’t pluralise “1 items”.  Patch by Hugo van Kemenade.

   - gh-117205(17): Speed up *note compileall.compile_dir(): b3e. by 20%
     when using multiprocessing by increasing ‘chunksize’.

   - gh-117178(18): Fix regression in lazy loading of self-referential
     modules, introduced in gh-114781(19).

   - gh-112383(20): Fix *note dis: 38. module’s handling of
     ‘ENTER_EXECUTOR’ instructions.

   - gh-117182(21): Lazy-loading of modules that modify their own
     ‘__class__’ no longer reverts the ‘__class__’ to *note
     types.ModuleType: e45.

   - gh-117084(22): Fix *note zipfile: 131. extraction for directory
     entries with the name containing backslashes on Windows.

   - gh-117114(23): Make *note os.path.isdevdrive(): 1756. available on
     all platforms.  For those that do not offer Dev Drives, it will
     always return ‘False’.

   - gh-117110(24): Fix a bug that prevents subclasses of *note
     typing.Any: 6af. to be instantiated with arguments.  Patch by Chris
     Fu.

   - gh-109653(25): Deferred select imports in importlib.metadata and
     importlib.resources for a 14% speedup.

   - gh-70647(26): Start the deprecation period for the current behavior
     of *note datetime.datetime.strptime(): 1714. and *note
     time.strptime(): 147b. which always fails to parse a date string
     with a *note ValueError: 202. involving a day of month such as
     ‘strptime("02-29", "%m-%d")’ when a year is 'not' specified and the
     date happen to be February 29th.  This should help avoid users
     finding new bugs every four years due to a natural mistaken
     assumption about the API when parsing partial date values.

   - gh-116987(27): Fixed ‘inspect.findsource()’ for class code objects.

   - gh-114099(28): Modify standard library to allow for iOS platform
     differences.

   - gh-90872(29): On Windows, *note subprocess.Popen.wait(): d0b. no
     longer calls ‘WaitForSingleObject()’ with a negative timeout: pass
     ‘0’ ms if the timeout is negative.  Patch by Victor Stinner.

   - gh-116957(30): configparser: Don’t leave ConfigParser values in an
     invalid state (stored as a list instead of a str) after an earlier
     read raised DuplicateSectionError or DuplicateOptionError.

   - gh-115538(31): ‘_io.WindowsConsoleIO’ now emit a warning if a
     boolean value is passed as a filedescriptor argument.

   - gh-90095(32): Ignore empty lines and comments in ‘.pdbrc’

   - gh-106531(33): Refreshed zipfile._path from zipp 3.18(34),
     providing better compatibility for PyPy, better glob performance
     for deeply nested zipfiles, and providing internal access to
     ‘CompleteDirs.inject’ for use in other tests (like
     importlib.resources).

   - gh-63207(35): On Windows, *note time.time(): 254. now uses the
     ‘GetSystemTimePreciseAsFileTime()’ clock to have a resolution
     better than 1 us, instead of the ‘GetSystemTimeAsFileTime()’ clock
     which has a resolution of 15.6 ms.  Patch by Victor Stinner.

   - gh-116764(36): Restore support of ‘None’ and other false values in
     *note urllib.parse: 10a. functions *note parse_qs(): 27a. and *note
     parse_qsl(): 279.  Also, they now raise a TypeError for non-zero
     integers and non-empty sequences.

   - gh-116811(37): In ‘PathFinder.invalidate_caches’, delegate to
     ‘MetadataPathFinder.invalidate_caches’.

   - gh-116647(38): Fix recursive child in dataclasses

   - gh-113171(39): Fixed various false positives and false negatives in

        * *note ipaddress.IPv4Address.is_private: 1757. (see these docs
          for details)

        * *note ipaddress.IPv4Address.is_global: f98.

        * *note ipaddress.IPv6Address.is_private: 1758.

        * *note ipaddress.IPv6Address.is_global: 1759.

     Also in the corresponding *note ipaddress.IPv4Network: 1fe. and
     *note ipaddress.IPv6Network: 1ff. attributes.

   - gh-63283(40): In *note encodings.idna: 52, any capitalization of
     the ACE prefix (‘xn--’) is now acceptable.  Patch by Pepijn de Vos
     and Zackery Spytz.

   - gh-71042(41): Add *note platform.android_ver(): 175a, which
     provides device and OS information on Android.

   - gh-73468(42): Added new *note math.fma(): 205. function, wrapping
     C99’s ‘fma()’ operation: fused multiply-add function.  Patch by
     Mark Dickinson and Victor Stinner.

   - gh-116608(43): The *note importlib.resources: 7b. functions *note
     is_resource(): 1ec, *note open_binary(): 1ed, *note open_text():
     1ee, *note path(): 1ef, *note read_binary(): 1f0, and *note
     read_text(): 1f1. are un-deprecated, and support subdirectories via
     multiple positional arguments.  The *note contents(): 1f2. function
     also allows subdirectories, but remains deprecated.

   - gh-116484(44): Change automatically generated ‘tkinter.Checkbutton’
     widget names to avoid collisions with automatically generated
     ‘tkinter.ttk.Checkbutton’ widget names within the same parent
     widget.

   - gh-114314(45): In *note ctypes: 2a, ctype data is now stored in
     type objects directly rather than in a dict subclass.  This is an
     internal change that should not affect usage.

   - gh-116401(46): Fix blocking *note os.fwalk(): b77. and *note
     shutil.rmtree(): 301. on opening named pipe.

   - gh-71052(47): Implement *note ctypes.util.find_library(): d72. on
     Android.

   - gh-90535(48): Fix support of 'interval' values > 1 in
     ‘logging.TimedRotatingFileHandler’ for ‘when='MIDNIGHT'’ and
     ‘when='Wx'’.

   - gh-113308(49): Remove some internal protected parts from *note
     uuid: 110.: ‘_has_uuid_generate_time_safe’, ‘_netbios_getnode’,
     ‘_ipconfig_getnode’, and ‘_load_system_functions’.  They were
     unused.

   - gh-115627(50): Fix the *note ssl: d0. module error handling of
     connection terminate by peer.  It now throws an OSError with the
     appropriate error code instead of an EOFError.

   - gh-114847(51): Speed up *note os.path.realpath(): 225. on
     non-Windows platforms.

   - gh-114271(52): Fix a race in ‘threading.Thread.join()’.

     ‘threading._MainThread’ now always represents the main thread of
     the main interpreter.

     ‘PyThreadState.on_delete’ and ‘PyThreadState.on_delete_data’ have
     been removed.

   - gh-113538(53): Add *note asyncio.Server.close_clients(): 1b2. and
     *note asyncio.Server.abort_clients(): 1b3. methods which allow to
     more forcefully close an asyncio server.

   - gh-85287(54): Changes Unicode codecs to return UnicodeEncodeError
     or UnicodeDecodeError, rather than just UnicodeError.

   - gh-113548(55): *note pdb: a5. now allows CLI arguments to ‘pdb -m’.

   - gh-112948(56): Make completion of *note pdb: a5. similar to Python
     REPL

   - gh-105866(57): Fixed ‘_get_slots’ bug which caused error when
     defining dataclasses with slots and a weakref_slot.

   - gh-96471(58): Add *note asyncio.Queue: a85. termination with *note
     shutdown(): 1b0. method.

   - gh-89739(59): The *note zipimport: 132. module can now read ZIP64
     files.

   - bpo-33533(60): *note asyncio.as_completed(): 1aa. now returns an
     object that is both an asynchronous iterator and plain iterator.
     The new asynchronous iteration pattern allows for easier
     correlation between prior tasks and their completed results.  This
     is a closer match to *note concurrent.futures.as_completed():
     175b.’s iteration pattern.  Patch by Justin Arthur.

   - bpo-27578(61): *note inspect.getsource(): 1619. (and related
     functions) work with empty module files, returning ‘'\n'’ (or
     reasonable equivalent) instead of raising ‘OSError’.  Patch by
     Kernc.

   - bpo-37141(62): Accept an iterable of separators in *note
     asyncio.StreamReader.readuntil(): 1b4, stopping when one of them is
     encountered.

   - gh-66543(63): Make *note mimetypes.guess_type(): 208. properly
     parsing of URLs with only a host name, URLs containing fragment or
     query, and filenames with only a UNC sharepoint on Windows.  Based
     on patch by Dong-hee Na.

   - bpo-15010(64): *note unittest.TestLoader.discover(): 1020. now
     saves the original value of ‘unittest.TestLoader._top_level_dir’
     and restores it at the end of the call.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117648

   (2) https://github.com/python/cpython/issues/117584

   (3) https://github.com/python/cpython/issues/117467

   (4) https://github.com/python/cpython/issues/114848

   (5) https://github.com/python/cpython/issues/117459

   (6) https://github.com/python/cpython/issues/117381

   (7) https://github.com/python/cpython/issues/117337

   (8) https://github.com/python/cpython/issues/117349

   (9) https://github.com/python/cpython/issues/117348

   (10) https://github.com/python/cpython/issues/117335

   (11) https://github.com/python/cpython/issues/66449

   (12) https://github.com/python/cpython/issues/88014

   (13) https://github.com/python/cpython/issues/117310

   (14) https://github.com/python/cpython/issues/117294

   (15) https://github.com/python/cpython/issues/98966

   (16) https://github.com/python/cpython/issues/117225

   (17) https://github.com/python/cpython/issues/117205

   (18) https://github.com/python/cpython/issues/117178

   (19) https://github.com/python/cpython/issues/114781

   (20) https://github.com/python/cpython/issues/112383

   (21) https://github.com/python/cpython/issues/117182

   (22) https://github.com/python/cpython/issues/117084

   (23) https://github.com/python/cpython/issues/117114

   (24) https://github.com/python/cpython/issues/117110

   (25) https://github.com/python/cpython/issues/109653

   (26) https://github.com/python/cpython/issues/70647

   (27) https://github.com/python/cpython/issues/116987

   (28) https://github.com/python/cpython/issues/114099

   (29) https://github.com/python/cpython/issues/90872

   (30) https://github.com/python/cpython/issues/116957

   (31) https://github.com/python/cpython/issues/115538

   (32) https://github.com/python/cpython/issues/90095

   (33) https://github.com/python/cpython/issues/106531

   (34) https://zipp.readthedocs.io/en/latest/history.html#v3-18-0

   (35) https://github.com/python/cpython/issues/63207

   (36) https://github.com/python/cpython/issues/116764

   (37) https://github.com/python/cpython/issues/116811

   (38) https://github.com/python/cpython/issues/116647

   (39) https://github.com/python/cpython/issues/113171

   (40) https://github.com/python/cpython/issues/63283

   (41) https://github.com/python/cpython/issues/71042

   (42) https://github.com/python/cpython/issues/73468

   (43) https://github.com/python/cpython/issues/116608

   (44) https://github.com/python/cpython/issues/116484

   (45) https://github.com/python/cpython/issues/114314

   (46) https://github.com/python/cpython/issues/116401

   (47) https://github.com/python/cpython/issues/71052

   (48) https://github.com/python/cpython/issues/90535

   (49) https://github.com/python/cpython/issues/113308

   (50) https://github.com/python/cpython/issues/115627

   (51) https://github.com/python/cpython/issues/114847

   (52) https://github.com/python/cpython/issues/114271

   (53) https://github.com/python/cpython/issues/113538

   (54) https://github.com/python/cpython/issues/85287

   (55) https://github.com/python/cpython/issues/113548

   (56) https://github.com/python/cpython/issues/112948

   (57) https://github.com/python/cpython/issues/105866

   (58) https://github.com/python/cpython/issues/96471

   (59) https://github.com/python/cpython/issues/89739

   (60) https://bugs.python.org/issue?@action=redirect&bpo=33533

   (61) https://bugs.python.org/issue?@action=redirect&bpo=27578

   (62) https://bugs.python.org/issue?@action=redirect&bpo=37141

   (63) https://github.com/python/cpython/issues/66543

   (64) https://bugs.python.org/issue?@action=redirect&bpo=15010


File: python.info,  Node: Documentation<14>,  Next: Tests<16>,  Prev: Library<32>,  Up: Python 3 13 0 alpha 6

1.23.22.5 Documentation
.......................

   - gh-115977(1): Remove compatibility references to Emscripten.

   - gh-114099(2): Add an iOS platform guide, and flag modules not
     available on iOS.

   - gh-91565(3): Changes to documentation files and config outputs to
     reflect the new location for reporting bugs - i.e.  GitHub rather
     than bugs.python.org.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115977

   (2) https://github.com/python/cpython/issues/114099

   (3) https://github.com/python/cpython/issues/91565


File: python.info,  Node: Tests<16>,  Next: Build<16>,  Prev: Documentation<14>,  Up: Python 3 13 0 alpha 6

1.23.22.6 Tests
...............

   - gh-83434(1): Disable JUnit XML output (‘--junit-xml=FILE’ command
     line option) in regrtest when hunting for reference leaks (‘-R’
     option).  Patch by Victor Stinner.

   - gh-117187(2): Fix XML tests for vanilla Expat <2.6.0.

   - gh-116333(3): Tests of TLS related things (error codes, etc) were
     updated to be more lenient about specific error message strings and
     behaviors as seen in the BoringSSL and AWS-LC forks of OpenSSL.

   - gh-117089(4): Consolidated tests for importlib.metadata in their
     own ‘metadata’ package.

   - gh-115979(5): Update test_importlib so that it passes under WASI
     SDK 21.

   - gh-112536(6): Add –tsan to test.regrtest for running TSAN tests in
     reasonable execution times.  Patch by Donghee Na.

   - gh-116307(7): Added import helper ‘isolated_modules’ as
     ‘CleanImport’ does not remove modules imported during the context.
     Use it in importlib.resources tests to avoid leaving ‘mod’ around
     to impede importlib.metadata tests.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/83434

   (2) https://github.com/python/cpython/issues/117187

   (3) https://github.com/python/cpython/issues/116333

   (4) https://github.com/python/cpython/issues/117089

   (5) https://github.com/python/cpython/issues/115979

   (6) https://github.com/python/cpython/issues/112536

   (7) https://github.com/python/cpython/issues/116307


File: python.info,  Node: Build<16>,  Next: Windows<14>,  Prev: Tests<16>,  Up: Python 3 13 0 alpha 6

1.23.22.7 Build
...............

   - gh-114736(1): Have WASI builds use WASI SDK 21.

   - gh-115983(2): Skip building test modules that must be built as
     shared under WASI.

   - gh-71052(3): Add Android build script and instructions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114736

   (2) https://github.com/python/cpython/issues/115983

   (3) https://github.com/python/cpython/issues/71052


File: python.info,  Node: Windows<14>,  Next: C API<16>,  Prev: Build<16>,  Up: Python 3 13 0 alpha 6

1.23.22.8 Windows
.................

   - gh-117267(1): Ensure ‘DirEntry.stat().st_ctime’ behaves
     consistently with *note os.stat(): 4a3. during the deprecation
     period of ‘st_ctime’ by containing the same value as
     ‘st_birthtime’.  After the deprecation period, ‘st_ctime’ will be
     the metadata change time (or unavailable through ‘DirEntry’), and
     only ‘st_birthtime’ will contain the creation time.

   - gh-116195(2): Improves performance of *note os.getppid(): 1760. by
     using an alternate system API when available.  Contributed by
     vxiiduu.

   - gh-88494(3): On Windows, *note time.monotonic(): 253. now uses the
     ‘QueryPerformanceCounter()’ clock to have a resolution better than
     1 us, instead of the ‘GetTickCount64()’ clock which has a
     resolution of 15.6 ms.  Patch by Victor Stinner.

   - gh-116773(4): Fix instances of ‘<_overlapped.Overlapped object at
     0xXXX> still has pending operation at deallocation, the process may
     crash’.

   - gh-91227(5): Fix the asyncio ProactorEventLoop implementation so
     that sending a datagram to an address that is not listening does
     not prevent receiving any more datagrams.

   - gh-115119(6): Switched from vendored ‘libmpdecimal’ code to a
     separately-hosted external package in the ‘cpython-source-deps’
     repository when building the ‘_decimal’ module.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117267

   (2) https://github.com/python/cpython/issues/116195

   (3) https://github.com/python/cpython/issues/88494

   (4) https://github.com/python/cpython/issues/116773

   (5) https://github.com/python/cpython/issues/91227

   (6) https://github.com/python/cpython/issues/115119


File: python.info,  Node: C API<16>,  Prev: Windows<14>,  Up: Python 3 13 0 alpha 6

1.23.22.9 C API
...............

   - gh-117642(1): Fix PEP 737(2) implementation for ‘%#T’ and ‘%#N’.

   - gh-87193(3): *note _PyBytes_Resize(): 1762. can now be called for
     bytes objects with reference count > 1, including 1-byte bytes
     objects.  It creates a new bytes object and destroys the old one if
     it has reference count > 1.

   - gh-117021(4): Fix integer overflow in *note PyLong_AsPid(): 1763.
     on non-Windows 64-bit platforms.

   - gh-115756(5): ‘PyCode_GetFirstFree()’ is an ustable API now and has
     been renamed to *note PyUnstable_Code_GetFirstFree(): 389.
     (Contributed by Bogdan Romanyuk in gh-115781(6))

   - gh-116869(7): Add ‘test_cext’ test: build a C extension to check if
     the Python C API emits C compiler warnings.  Patch by Victor
     Stinner.

   - gh-116869(8): Make the C API compatible with
     ‘-Werror=declaration-after-statement’ compiler flag again.  Patch
     by Victor Stinner.

   - gh-116936(9): Add *note PyType_GetModuleByDef(): 397. to the
     limited C API. Patch by Victor Stinner.

   - gh-116809(10): Restore removed private ‘_PyErr_ChainExceptions1()’
     function.  Patch by Victor Stinner.

   - gh-115754(11): In the limited C API version 3.13, getting
     ‘Py_None’, ‘Py_False’, ‘Py_True’, ‘Py_Ellipsis’ and
     ‘Py_NotImplemented’ singletons is now implemented as function calls
     at the stable ABI level to hide implementation details.  Getting
     these constants still return borrowed references.  Patch by Victor
     Stinner.

   - gh-115754(12): Add *note Py_GetConstant(): 357. and *note
     Py_GetConstantBorrowed(): 358. functions to get constants.  For
     example, ‘Py_GetConstant(Py_CONSTANT_ZERO)’ returns a *note strong
     reference: 33e. to the constant zero.  Patch by Victor Stinner.

   - gh-111696(13): Add support for ‘%T’, ‘%T#’, ‘%N’ and ‘%N#’ formats
     to *note PyUnicode_FromFormat(): 38d.: format the fully qualified
     name of an object type and of a type: call *note
     PyType_GetModuleName(): 378.  See PEP 737(14) for more information.
     Patch by Victor Stinner.

   - gh-111696(15): Add *note PyType_GetModuleName(): 378. function to
     get the type’s module name.  Equivalent to getting the
     ‘type.__module__’ attribute.  Patch by Eric Snow and Victor
     Stinner.

   - gh-111696(16): Add *note PyType_GetFullyQualifiedName(): 376.
     function to get the type’s fully qualified name.  Equivalent to
     ‘f"{type.__module__}.{type.__qualname__}"’, or ‘type.__qualname__’
     if ‘type.__module__’ is not a string or is equal to ‘"builtins"’.
     Patch by Victor Stinner.

   - gh-85283(17): The ‘fcntl’, ‘grp’, ‘pwd’, ‘termios’, ‘_statistics’
     and ‘_testconsole’ C extensions are now built with the *note
     limited C API: 399.  Patch by Victor Stinner.

   - gh-111140(18): Add additional flags to *note
     PyLong_AsNativeBytes(): 364. and *note PyLong_FromNativeBytes():
     365. to allow the caller to determine how to handle edge cases
     around values that fill the entire buffer.

   - gh-113024(19): Add *note PyObject_GenericHash(): 36a. function.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/117642

   (2) https://peps.python.org/pep-0737/

   (3) https://github.com/python/cpython/issues/87193

   (4) https://github.com/python/cpython/issues/117021

   (5) https://github.com/python/cpython/issues/115756

   (6) https://github.com/python/cpython/issues/115781

   (7) https://github.com/python/cpython/issues/116869

   (8) https://github.com/python/cpython/issues/116869

   (9) https://github.com/python/cpython/issues/116936

   (10) https://github.com/python/cpython/issues/116809

   (11) https://github.com/python/cpython/issues/115754

   (12) https://github.com/python/cpython/issues/115754

   (13) https://github.com/python/cpython/issues/111696

   (14) https://peps.python.org/pep-0737/

   (15) https://github.com/python/cpython/issues/111696

   (16) https://github.com/python/cpython/issues/111696

   (17) https://github.com/python/cpython/issues/85283

   (18) https://github.com/python/cpython/issues/111140

   (19) https://github.com/python/cpython/issues/113024


File: python.info,  Node: Python 3 13 0 alpha 5,  Next: Python 3 13 0 alpha 4,  Prev: Python 3 13 0 alpha 6,  Up: Changelog

1.23.23 Python 3.13.0 alpha 5
-----------------------------

'Release date: 2024-03-12'

* Menu:

* Security: Security<15>.
* Core and Builtins: Core and Builtins<29>.
* Library: Library<33>.
* Core and Builtins: Core and Builtins<30>.
* Library: Library<34>.
* Core and Builtins: Core and Builtins<31>.
* Library: Library<35>.
* Documentation: Documentation<15>.
* Tests: Tests<17>.
* Build: Build<17>.
* Windows: Windows<15>.
* macOS: macOS<10>.
* IDLE: IDLE<13>.
* Tools/Demos: Tools/Demos<9>.
* C API: C API<17>.


File: python.info,  Node: Security<15>,  Next: Core and Builtins<29>,  Up: Python 3 13 0 alpha 5

1.23.23.1 Security
..................

   - gh-115398(1): Allow controlling Expat >=2.6.0 reparse deferral (
     CVE 2023-52425(2)) by adding five new methods:

        * *note xml.etree.ElementTree.XMLParser.flush(): 26f.

        * *note xml.etree.ElementTree.XMLPullParser.flush(): 270.

        * *note xml.parsers.expat.xmlparser.GetReparseDeferralEnabled():
          271.

        * *note xml.parsers.expat.xmlparser.SetReparseDeferralEnabled():
          272.

        * ‘xml.sax.expatreader.ExpatParser.flush()’

   - gh-114572(3): *note ssl.SSLContext.cert_store_stats(): fe5. and
     *note ssl.SSLContext.get_ca_certs(): fe6. now correctly lock access
     to the certificate store, when the *note ssl.SSLContext: 294. is
     shared across multiple threads.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115398

   (2) https://www.cve.org/CVERecord?id=CVE-2023-52425

   (3) https://github.com/python/cpython/issues/114572


File: python.info,  Node: Core and Builtins<29>,  Next: Library<33>,  Prev: Security<15>,  Up: Python 3 13 0 alpha 5

1.23.23.2 Core and Builtins
...........................

   - gh-116604(1): Respect the status of the garbage collector when
     indirect calls are made via *note PyErr_CheckSignals(): 46a. and
     the evaluation breaker.  Patch by Pablo Galindo

   - gh-112087(2): *note list: 614. is now compatible with the
     implementation of PEP 703(3).

   - gh-116381(4): Add specialization for ‘CONTAINS_OP’.

   - gh-116296(5): Fix possible refleak in ‘object.__reduce__()’
     internal error handling.

   - gh-115823(6): Properly calculate error ranges in the parser when
     raising *note SyntaxError: 18d. exceptions caused by invalid byte
     sequences.  Patch by Pablo Galindo

   - gh-115778(7): Add ‘tierN’ annotation for instruction definition in
     interpreter DSL.

   - gh-115733(8): Fix crash when calling ‘next()’ on exhausted list
     iterators.

   - gh-115700(9): The regen-cases build stage now works on Windows.

   - gh-115347(10): Fix bug where docstring was replaced by a redundant
     NOP when Python is run with ‘-OO’.

   - gh-115323(11): Make error message more meaningful for when *note
     bytearray.extend(): 15dc. is called with a *note str: 44f. object.

   - gh-112175(12): Every ‘PyThreadState’ now has its own
     ‘eval_breaker’, allowing specific threads to be interrupted.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116604

   (2) https://github.com/python/cpython/issues/112087

   (3) https://peps.python.org/pep-0703/

   (4) https://github.com/python/cpython/issues/116381

   (5) https://github.com/python/cpython/issues/116296

   (6) https://github.com/python/cpython/issues/115823

   (7) https://github.com/python/cpython/issues/115778

   (8) https://github.com/python/cpython/issues/115733

   (9) https://github.com/python/cpython/issues/115700

   (10) https://github.com/python/cpython/issues/115347

   (11) https://github.com/python/cpython/issues/115323

   (12) https://github.com/python/cpython/issues/112175


File: python.info,  Node: Library<33>,  Next: Core and Builtins<30>,  Prev: Core and Builtins<29>,  Up: Python 3 13 0 alpha 5

1.23.23.3 Library
.................

   - gh-115154(1): Fix a bug that was causing the *note
     tokenize.untokenize(): 168a. function to handle unicode named
     literals incorrectly.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115154


File: python.info,  Node: Core and Builtins<30>,  Next: Library<34>,  Prev: Library<33>,  Up: Python 3 13 0 alpha 5

1.23.23.4 Core and Builtins
...........................

   - gh-112433(1): Add ability to force alignment of *note
     ctypes.Structure: 1d4. by way of the new ‘_align_’ attribute on the
     class.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112433


File: python.info,  Node: Library<34>,  Next: Core and Builtins<31>,  Prev: Core and Builtins<30>,  Up: Python 3 13 0 alpha 5

1.23.23.5 Library
.................

   - gh-104090(1): The multiprocessing resource tracker now exits with
     non-zero status code if a resource leak was detected.  It still
     exits with status code 0 otherwise.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104090


File: python.info,  Node: Core and Builtins<31>,  Next: Library<35>,  Prev: Library<34>,  Up: Python 3 13 0 alpha 5

1.23.23.6 Core and Builtins
...........................

   - gh-105858(1): Improve the constructors for *note ast: 8. nodes.
     Arguments of list types now default to an empty list if omitted,
     and optional fields default to ‘None’.  AST nodes now have an
     ‘__annotations__’ attribute with the expected types of their
     attributes.  Passing unrecognized extra arguments to AST nodes is
     deprecated and will become an error in Python 3.15.  Omitting a
     required argument to an AST node is deprecated and will become an
     error in Python 3.15.  Patch by Jelle Zijlstra.

   - gh-101860(2): Expose ‘__name__’ attribute on property.

   - gh-96497(3): Fix incorrect resolution of mangled class variables
     used in assignment expressions in comprehensions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/105858

   (2) https://github.com/python/cpython/issues/101860

   (3) https://github.com/python/cpython/issues/96497


File: python.info,  Node: Library<35>,  Next: Documentation<15>,  Prev: Core and Builtins<31>,  Up: Python 3 13 0 alpha 5

1.23.23.7 Library
.................

   - gh-116600(1): Fix *note repr(): 803. for global *note Flag: 626.
     members.

   - gh-116349(2): *note platform.java_ver(): 2a7. is deprecated and
     will be removed in 3.15.  It was largely untested, had a confusing
     API, and was only useful for Jython support.

   - gh-116143(3): Fix a race in pydoc ‘_start_server’, eliminating a
     window in which ‘_start_server’ can return a thread that is
     “serving” but without a ‘docserver’ set.

   - gh-116127(4): *note typing: 104.: implement PEP 705(5) which adds
     *note typing.ReadOnly: 161. support to *note typing.TypedDict: 162.

   - gh-116325(6): *note typing: 104.: raise *note SyntaxError: 18d.
     instead of *note AttributeError: 34e. on forward references as
     empty strings.

   - gh-115957(7): When ‘asyncio.TaskGroup.create_task’ is called on an
     inactive ‘asyncio.TaskGroup’, the given coroutine will be closed
     (which prevents a ‘RuntimeWarning’).

   - gh-115978(8): Disable preadv(), readv(), pwritev(), and writev() on
     WASI.

     Under wasmtime for WASI 0.2, these functions don’t pass test_posix
     (‘https://github.com/bytecodealliance/wasmtime/issues/7830’).

   - gh-88352(9): Fix the computation of the next rollover time in the
     ‘logging.TimedRotatingFileHandler’ handler.  ‘computeRollover()’
     now always returns a timestamp larger than the specified time and
     works correctly during the DST change.  ‘doRollover()’ no longer
     overwrite the already rolled over file, saving from data loss when
     run at midnight or during repeated time at the DST change.

   - gh-87115(10): Set ‘__main__.__spec__’ to ‘None’ when running a
     script with *note pdb: a5.

   - gh-76511(11): Fix UnicodeEncodeError in ‘email.Message.as_string()’
     that results when a message that claims to be in the ascii
     character set actually has non-ascii characters.  Non-ascii
     characters are now replaced with the U+FFFD replacement character,
     like in the ‘replace’ error handler.

   - gh-89547(12): Add support for nested typing special forms like
     Final[ClassVar[int]].

   - gh-65824(13): Improve the ‘less’ prompt in *note pydoc: b5.

   - gh-116040(14): [Enum] fix by-value calls when second value is
     falsey; e.g.  Cardinal(1, 0)

   - gh-115821(15): [Enum] Improve error message when calling
     super().__new__() in custom __new__.

   - gh-85644(16): Use the ‘XDG_CURRENT_DESKTOP’ environment variable in
     *note webbrowser: 115. to check desktop.  Prefer it to the
     deprecated ‘GNOME_DESKTOP_SESSION_ID’ for GNOME detection.

   - gh-75988(17): Fixed *note unittest.mock.create_autospec(): 1712. to
     pass the call through to the wrapped object to return the real
     result.

   - gh-115881(18): Fix issue where *note ast.parse(): 1a8. would
     incorrectly flag conditional context managers (such as ‘with (x()
     if y else z()): ...’) as invalid syntax if ‘feature_version=(3, 8)’
     was passed.  This reverts changes to the grammar made as part of
     gh-94949(19).

   - gh-115886(20): Fix silent truncation of the name with an embedded
     null character in *note multiprocessing.shared_memory.SharedMemory:
     176c.

   - gh-115532(21): Add kernel density estimation to the statistics
     module.

   - gh-115714(22): On WASI, the *note time: ee. module no longer get
     process time using ‘times()’ or ‘CLOCK_PROCESS_CPUTIME_ID’, system
     API is that is unreliable and is likely to be removed from WASI.
     The affected clock functions fall back to calling ‘clock()’.

   - gh-115809(23): Improve algorithm for computing which rolled-over
     log files to delete in ‘logging.TimedRotatingFileHandler’.  It is
     now reliable for handlers without ‘namer’ and with arbitrary
     deterministic ‘namer’ that leaves the datetime part in the file
     name unmodified.

   - gh-74668(24): *note urllib.parse: 10a. functions *note parse_qs():
     27a. and *note parse_qsl(): 279. now support bytes arguments
     containing raw and percent-encoded non-ASCII data.

   - gh-67044(25): *note csv.writer(): 48a. now always quotes or escapes
     ‘'\r'’ and ‘'\n'’, regardless of 'lineterminator' value.

   - gh-115712(26): Restore support of space delimiter with
     ‘skipinitialspace=True’ in *note csv: 29.  *note csv.writer(): 48a.
     now quotes empty fields if delimiter is a space and
     skipinitialspace is true and raises exception if quoting is not
     possible.

   - gh-112364(27): Fixed *note ast.unparse(): 8ee. to handle
     format_spec with ‘"’, ‘'’ or ‘\\’.  Patched by Frank Hoffmann.

   - gh-112997(28): Stop logging potentially sensitive callback
     arguments in *note asyncio: a. unless debug mode is active.

   - gh-114914(29): Fix an issue where an abandoned ‘StreamWriter’ would
     not be garbage collected.

   - gh-111358(30): Fix a bug in
     ‘asyncio.BaseEventLoop.shutdown_default_executor()’ to ensure the
     timeout passed to the coroutine behaves as expected.

   - gh-115618(31): Fix improper decreasing the reference count for
     ‘None’ argument in *note property: 194. methods *note getter():
     176d, *note setter(): 176e. and *note deleter(): 176f.

   - gh-112720(32): Refactor ‘dis.ArgResolver’ to make it possible to
     subclass and change the way jump args are interpreted.

   - gh-112006(33): Fix *note inspect.unwrap(): f95. for types with the
     ‘__wrapper__’ data descriptor.  Fix *note
     inspect.Signature.from_callable(): 73d. for builtins *note
     classmethod(): 166. and *note staticmethod(): 419.

   - gh-101293(34): Support callables with the ‘__call__()’ method and
     types with ‘__new__()’ and ‘__init__()’ methods set to class
     methods, static methods, bound methods, partial functions, and
     other types of methods and descriptors in *note
     inspect.Signature.from_callable(): 73d.

   - gh-103092(35): Isolate ‘_lsprof’ (apply PEP 687(36)).

   - gh-113942(37): *note pydoc: b5. no longer skips global functions
     implemented as builtin methods, such as ‘MethodDescriptorType’ and
     ‘WrapperDescriptorType’.

   - gh-115256(38): Added DeprecationWarning when accessing the tarfile
     attribute of TarInfo objects.  The attribute is never used
     internally and is only attached to TarInfos when the tarfile is
     opened in write-mode, not read-mode.  The attribute creates an
     unnecessary reference cycle which may cause corruption when not
     closing the handle after writing a tarfile.

   - gh-115197(39): ‘urllib.request’ no longer resolves the hostname
     before checking it against the system’s proxy bypass list on macOS
     and Windows.

   - gh-113812(40): ‘DatagramTransport.sendto()’ will now send
     zero-length datagrams if called with an empty bytes object.  The
     transport flow control also now accounts for the datagram header
     when calculating the buffer size.

   - gh-114763(41): Protect modules loaded with *note
     importlib.util.LazyLoader: cd3. from race conditions when multiple
     threads try to access attributes before the loading is complete.

   - gh-114709(42): ‘posixpath.commonpath()’ now raises a *note
     ValueError: 202. exception when passed an empty iterable.
     Previously, *note IndexError: 1585. was raised.

     ‘posixpath.commonpath()’ now raises a *note TypeError: 2c3.
     exception when passed ‘None’.  Previously, *note ValueError: 202.
     was raised.

   - gh-114610(43): Fix bug where *note pathlib.PurePath.with_stem():
     1770. converted a non-empty path suffix to a stem when given an
     empty 'stem' argument.  It now raises *note ValueError: 202, just
     like *note pathlib.PurePath.with_suffix(): 1721. does when called
     on a path with an empty stem, given a non-empty 'suffix' argument.

   - gh-107361(44): Add *note ssl.VERIFY_X509_PARTIAL_CHAIN: 156. and
     ‘VERIFY_X509_STRICT’ to the default SSL context created with *note
     ssl.create_default_context(): 155.

   - gh-112281(45): Allow creating *note union of types: 7c6. for *note
     typing.Annotated: 947. with unhashable metadata.

   - gh-111775(46): Fix
     ‘importlib.resources.simple.ResourceHandle.open()’ for text mode,
     added missed ‘stream’ argument.

   - gh-90095(47): Make .pdbrc and -c work with any valid pdb commands.

   - gh-107625(48): Raise *note configparser.ParsingError: 508. from
     *note read(): 14b7. and *note read_file(): 509. methods of *note
     configparser.ConfigParser: 1c8. if a key without a corresponding
     value is continued (that is, followed by an indented line).

   - gh-107155(49): Fix incorrect output of ‘help(x)’ where ‘x’ is a
     *note lambda: 12e4. function, which has an ‘__annotations__’
     dictionary attribute with a ‘"return"’ key.

   - gh-57141(50): Add option for 'non-shallow' comparisons to *note
     filecmp.dircmp: f78. like *note filecmp.cmp(): 1771.  Original
     patch by Steven Ward.  Enhanced by Tobias Rautenkranz

   - gh-69990(51): ‘Profile.print_stats()’ has been improved to accept
     multiple sort arguments.  Patched by Chiu-Hsiang Hsu and Furkan
     Onder.

   - gh-104061(52): Add ‘socket.SO_BINDTOIFINDEX’ constant.

   - gh-60346(53): Fix ArgumentParser inconsistent with
     parse_known_args.

   - gh-102389(54): Add ‘windows_31j’ to aliases for ‘cp932’ codec

   - gh-72249(55): Always include the *note module: 1772. name in the
     *note repr(): 803. of *note functools.partial(): 417. objects.
     Patch by Furkan Onder and Anilyka Barry.

   - gh-100985(56): Update HTTPSConnection to consistently wrap IPv6
     Addresses when using a proxy.

   - gh-100884(57): email: fix misfolding of comma in address-lists over
     multiple lines in combination with unicode encoding.

   - gh-95782(58): Fix ‘io.BufferedReader.tell()’,
     ‘io.BufferedReader.seek()’, ‘_pyio.BufferedReader.tell()’,
     ‘io.BufferedRandom.tell()’, ‘io.BufferedRandom.seek()’ and
     ‘_pyio.BufferedRandom.tell()’ being able to return negative
     offsets.

   - gh-96310(59): Fix a traceback in *note argparse: 6. when all
     options in a mutually exclusive group are suppressed.

   - gh-93205(60): Fixed a bug in *note
     logging.handlers.TimedRotatingFileHandler: f9a. where multiple
     rotating handler instances pointing to files with the same name but
     different extensions would conflict and not delete the correct
     files.

   - bpo-31116(61): Add Z85 encoding to ‘base64’.

   - bpo-44865(62): Add missing call to localization function in *note
     argparse: 6.

   - bpo-43952(63): Fix *note
     multiprocessing.connection.Listener.accept(): 1773. to accept empty
     bytes as authkey.  Not accepting empty bytes as key causes it to
     hang indefinitely.

   - bpo-42125(64): linecache: get module name from ‘__spec__’ if
     available.  This allows getting source code for the ‘__main__’
     module when a custom loader is used.

   - bpo-41122(65): Failing to pass arguments properly to *note
     functools.singledispatchmethod(): 9fb. now throws a TypeError
     instead of hitting an index out of bounds internally.

   - bpo-40818(66): The asyncio REPL now runs *note
     sys.__interactivehook__: 1002. on startup.  The default
     implementation of ‘sys.__interactivehook__’ provides
     auto-completion to the asyncio REPL. Patch contributed by Rémi
     Lapeyre.

   - bpo-33775(67): Add ‘default’ and ‘version’ help text for
     localization in argparse.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116600

   (2) https://github.com/python/cpython/issues/116349

   (3) https://github.com/python/cpython/issues/116143

   (4) https://github.com/python/cpython/issues/116127

   (5) https://peps.python.org/pep-0705/

   (6) https://github.com/python/cpython/issues/116325

   (7) https://github.com/python/cpython/issues/115957

   (8) https://github.com/python/cpython/issues/115978

   (9) https://github.com/python/cpython/issues/88352

   (10) https://github.com/python/cpython/issues/87115

   (11) https://github.com/python/cpython/issues/76511

   (12) https://github.com/python/cpython/issues/89547

   (13) https://github.com/python/cpython/issues/65824

   (14) https://github.com/python/cpython/issues/116040

   (15) https://github.com/python/cpython/issues/115821

   (16) https://github.com/python/cpython/issues/85644

   (17) https://github.com/python/cpython/issues/75988

   (18) https://github.com/python/cpython/issues/115881

   (19) https://github.com/python/cpython/issues/94949

   (20) https://github.com/python/cpython/issues/115886

   (21) https://github.com/python/cpython/issues/115532

   (22) https://github.com/python/cpython/issues/115714

   (23) https://github.com/python/cpython/issues/115809

   (24) https://github.com/python/cpython/issues/74668

   (25) https://github.com/python/cpython/issues/67044

   (26) https://github.com/python/cpython/issues/115712

   (27) https://github.com/python/cpython/issues/112364

   (28) https://github.com/python/cpython/issues/112997

   (29) https://github.com/python/cpython/issues/114914

   (30) https://github.com/python/cpython/issues/111358

   (31) https://github.com/python/cpython/issues/115618

   (32) https://github.com/python/cpython/issues/112720

   (33) https://github.com/python/cpython/issues/112006

   (34) https://github.com/python/cpython/issues/101293

   (35) https://github.com/python/cpython/issues/103092

   (36) https://peps.python.org/pep-0687/

   (37) https://github.com/python/cpython/issues/113942

   (38) https://github.com/python/cpython/issues/115256

   (39) https://github.com/python/cpython/issues/115197

   (40) https://github.com/python/cpython/issues/113812

   (41) https://github.com/python/cpython/issues/114763

   (42) https://github.com/python/cpython/issues/114709

   (43) https://github.com/python/cpython/issues/114610

   (44) https://github.com/python/cpython/issues/107361

   (45) https://github.com/python/cpython/issues/112281

   (46) https://github.com/python/cpython/issues/111775

   (47) https://github.com/python/cpython/issues/90095

   (48) https://github.com/python/cpython/issues/107625

   (49) https://github.com/python/cpython/issues/107155

   (50) https://github.com/python/cpython/issues/57141

   (51) https://github.com/python/cpython/issues/69990

   (52) https://github.com/python/cpython/issues/104061

   (53) https://github.com/python/cpython/issues/60346

   (54) https://github.com/python/cpython/issues/102389

   (55) https://github.com/python/cpython/issues/72249

   (56) https://github.com/python/cpython/issues/100985

   (57) https://github.com/python/cpython/issues/100884

   (58) https://github.com/python/cpython/issues/95782

   (59) https://github.com/python/cpython/issues/96310

   (60) https://github.com/python/cpython/issues/93205

   (61) https://bugs.python.org/issue?@action=redirect&bpo=31116

   (62) https://bugs.python.org/issue?@action=redirect&bpo=44865

   (63) https://bugs.python.org/issue?@action=redirect&bpo=43952

   (64) https://bugs.python.org/issue?@action=redirect&bpo=42125

   (65) https://bugs.python.org/issue?@action=redirect&bpo=41122

   (66) https://bugs.python.org/issue?@action=redirect&bpo=40818

   (67) https://bugs.python.org/issue?@action=redirect&bpo=33775


File: python.info,  Node: Documentation<15>,  Next: Tests<17>,  Prev: Library<35>,  Up: Python 3 13 0 alpha 5

1.23.23.8 Documentation
.......................

   - gh-115399(1): Document CVE 2023-52425(2) of Expat <2.6.0 under “XML
     vulnerabilities”.

   - gh-109653(3): Improve import time of *note uuid: 110. on Linux.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115399

   (2) https://www.cve.org/CVERecord?id=CVE-2023-52425

   (3) https://github.com/python/cpython/issues/109653


File: python.info,  Node: Tests<17>,  Next: Build<17>,  Prev: Documentation<15>,  Up: Python 3 13 0 alpha 5

1.23.23.9 Tests
...............

   - gh-71052(1): Add test exclusions to support running the test suite
     on Android.

   - gh-71052(2): Enable ‘test_concurrent_futures’ on platforms that
     support threading but not multiprocessing.

   - gh-115796(3): Make ‘_testinternalcapi.assemble_code_object’
     construct the exception table for the code object.

   - gh-115720(4): Leak tests (‘-R’, ‘--huntrleaks’) now show a summary
     of the number of leaks found in each iteration.

   - gh-115122(5): Add ‘--bisect’ option to regrtest test runner: run
     failed tests with ‘test.bisect_cmd’ to identify failing tests.
     Patch by Victor Stinner.

   - gh-115596(6): Fix ‘ProgramPriorityTests’ in ‘test_os’ permanently
     changing the process priority.

   - gh-115556(7): On Windows, commas passed in arguments to
     ‘Tools\buildbot\test.bat’ and ‘PCbuild\\rt.bat’ are now properly
     handled.

   - gh-115420(8): Fix translation of exception handler targets by
     ‘_testinternalcapi.optimize_cfg’.

   - gh-115376(9): Fix segfault in ‘_testinternalcapi.compiler_codegen’
     on bad input.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/71052

   (2) https://github.com/python/cpython/issues/71052

   (3) https://github.com/python/cpython/issues/115796

   (4) https://github.com/python/cpython/issues/115720

   (5) https://github.com/python/cpython/issues/115122

   (6) https://github.com/python/cpython/issues/115596

   (7) https://github.com/python/cpython/issues/115556

   (8) https://github.com/python/cpython/issues/115420

   (9) https://github.com/python/cpython/issues/115376


File: python.info,  Node: Build<17>,  Next: Windows<15>,  Prev: Tests<17>,  Up: Python 3 13 0 alpha 5

1.23.23.10 Build
................

   - gh-116313(1): Get WASI builds to work under wasmtime 18 w/ WASI
     0.2/preview2 primitives.

   - gh-71052(2): Change Android’s *note sys.platform: a9c. from
     ‘"linux"’ to ‘"android"’.

   - gh-116117(3): Backport ‘libb2’’s PR #42 to fix compiling CPython on
     32-bit Windows with ‘clang-cl’.

   - gh-71052(4): Fix several Android build issues

   - gh-114099(5): A testbed project was added to run the test suite on
     iOS.

   - gh-115350(6): Fix building ctypes module with -DWIN32_LEAN_AND_MEAN
     defined

   - gh-111225(7): Link extension modules against libpython on Android.

   - gh-115737(8): The install name for libPython is now correctly set
     for non-framework macOS builds.

   - gh-114099(9): Makefile targets were added to support compiling an
     iOS-compatible framework build.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116313

   (2) https://github.com/python/cpython/issues/71052

   (3) https://github.com/python/cpython/issues/116117

   (4) https://github.com/python/cpython/issues/71052

   (5) https://github.com/python/cpython/issues/114099

   (6) https://github.com/python/cpython/issues/115350

   (7) https://github.com/python/cpython/issues/111225

   (8) https://github.com/python/cpython/issues/115737

   (9) https://github.com/python/cpython/issues/114099


File: python.info,  Node: Windows<15>,  Next: macOS<10>,  Prev: Build<17>,  Up: Python 3 13 0 alpha 5

1.23.23.11 Windows
..................

   - gh-116012(1): Ensure the value of ‘GetLastError()’ is preserved
     across GIL operations.

   - gh-115582(2): Building extensions intended for free-threaded builds
     of CPython now require compiling with ‘/DPy_GIL_DISABLED’ manually
     when using a regular install.  This is expected to change in future
     releases.

   - gh-115554(3): The installer now has more strict rules about
     updating the *note Python Launcher for Windows: 5c1.  In general,
     most users only have a single launcher installed and will see no
     difference.  When multiple launchers have been installed, the
     option to install the launcher is disabled until all but one have
     been removed.  Downgrading the launcher (which was never allowed)
     is now more obviously blocked.

   - gh-115543(4): *note Python Launcher for Windows: 5c1. can now
     detect Python 3.13 when installed from the Microsoft Store, and
     will install Python 3.12 by default when ‘PYLAUNCHER_ALLOW_INSTALL’
     is set.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116012

   (2) https://github.com/python/cpython/issues/115582

   (3) https://github.com/python/cpython/issues/115554

   (4) https://github.com/python/cpython/issues/115543


File: python.info,  Node: macOS<10>,  Next: IDLE<13>,  Prev: Windows<15>,  Up: Python 3 13 0 alpha 5

1.23.23.12 macOS
................

   - gh-116145(1): Update macOS installer to Tcl/Tk 8.6.14.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/116145


File: python.info,  Node: IDLE<13>,  Next: Tools/Demos<9>,  Prev: macOS<10>,  Up: Python 3 13 0 alpha 5

1.23.23.13 IDLE
...............

   - gh-88516(1): On macOS show a proxy icon in the title bar of editor
     windows to match platform behaviour.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88516


File: python.info,  Node: Tools/Demos<9>,  Next: C API<17>,  Prev: IDLE<13>,  Up: Python 3 13 0 alpha 5

1.23.23.14 Tools/Demos
......................

   - gh-100176(1): Remove outdated Tools/{io,cc,string}bench

   - bpo-45101(2): Add consistency in usage message IO between 2
     versions of python-config.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100176

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45101


File: python.info,  Node: C API<17>,  Prev: Tools/Demos<9>,  Up: Python 3 13 0 alpha 5

1.23.23.15 C API
................

   - gh-114626(1): Add again ‘_PyCFunctionFastWithKeywords’ name,
     removed in Python 3.13 alpha 4 by mistake.  Keep the old private
     ‘_PyCFunctionFastWithKeywords’ name (Python 3.7) as an alias to the
     new public name ‘PyCFunctionFastWithKeywords’ (Python 3.13a4).
     Patch by Victor Stinner.

   - gh-111418(2): Add *note PyHASH_MODULUS: 177c, *note PyHASH_BITS:
     177d, *note PyHASH_INF: 177e. and *note PyHASH_IMAG: 177f. C
     macros.  Patch by Sergey B Kirpichev.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114626

   (2) https://github.com/python/cpython/issues/111418


File: python.info,  Node: Python 3 13 0 alpha 4,  Next: Python 3 13 0 alpha 3,  Prev: Python 3 13 0 alpha 5,  Up: Changelog

1.23.24 Python 3.13.0 alpha 4
-----------------------------

'Release date: 2024-02-15'

* Menu:

* Security: Security<16>.
* Core and Builtins: Core and Builtins<32>.
* Library: Library<36>.
* Documentation: Documentation<16>.
* Tests: Tests<18>.
* Build: Build<18>.
* Windows: Windows<16>.
* macOS: macOS<11>.
* IDLE: IDLE<14>.
* Tools/Demos: Tools/Demos<10>.
* C API: C API<18>.


File: python.info,  Node: Security<16>,  Next: Core and Builtins<32>,  Up: Python 3 13 0 alpha 4

1.23.24.1 Security
..................

   - gh-115399(1): Update bundled libexpat to 2.6.0

   - gh-115243(2): Fix possible crashes in *note
     collections.deque.index(): e00. when the deque is concurrently
     modified.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115399

   (2) https://github.com/python/cpython/issues/115243


File: python.info,  Node: Core and Builtins<32>,  Next: Library<36>,  Prev: Security<16>,  Up: Python 3 13 0 alpha 4

1.23.24.2 Core and Builtins
...........................

   - gh-112087(1): For an empty reverse iterator for list will be
     reduced to *note reversed(): 86c.  Patch by Donghee Na

   - gh-114570(2): Add *note PythonFinalizationError: 14d. exception.
     This exception derived from *note RuntimeError: 195. is raised when
     an operation is blocked during the *note Python finalization: 14e.
     Patch by Victor Stinner.

   - gh-114695(3): Add *note sys._clear_internal_caches(): 1783, which
     clears all internal performance-related caches (and deprecate the
     less-general *note sys._clear_type_cache(): 1784. function).

   - gh-114828(4): Fix compilation crashes in uncommon code examples
     using *note super(): 4de. inside a comprehension in a class body.

   - gh-112069(5): Adapt *note set: 5dc. and *note frozenset: 5dd.
     methods to Argument Clinic.

   - gh-115011(6): Setters for members with an unsigned integer type now
     support the same range of valid values for objects that has a *note
     __index__(): 720. method as for *note int: 257.

   - gh-114887(7): Changed socket type validation in *note
     create_datagram_endpoint(): 736. to accept all non-stream sockets.
     This fixes a regression in compatibility with raw sockets.

   - gh-114944(8): Fixes a race between ‘PyParkingLot_Park’ and
     ‘_PyParkingLot_UnparkAll’.

   - gh-113462(9): Limit the number of versions that a single class can
     use.  Prevents a few wayward classes using up all the version
     numbers.

   - gh-76763(10): The *note chr(): 1785. builtin function now always
     raises *note ValueError: 202. for values outside the valid range.
     Previously it raised *note OverflowError: 888. for very large or
     small values.

   - gh-114806(11): No longer specialize calls to classes, if those
     classes have metaclasses.  Fixes bug where the ‘__call__’ method of
     the metaclass was not being called.

   - gh-107944(12): Improve error message for function calls with bad
     keyword arguments via getargs

   - gh-112529(13): The free-threaded build no longer allocates space
     for the ‘PyGC_Head’ structure in objects that support cyclic
     garbage collection.  A number of other fields and data structures
     are used as replacements, including ‘ob_gc_bits’, ‘ob_tid’, and
     mimalloc internal data structures.

   - gh-114456(14): Lower the recursion limit under a debug build of
     WASI.

   - gh-114083(15): Compiler applies folding of LOAD_CONST with
     following instruction in a separate pass before other
     optimisations.  This enables jump threading in certain
     circumstances.

   - gh-114388(16): Fix a *note RuntimeWarning: 1bd. emitted when assign
     an integer-like value that is not an instance of *note int: 257. to
     an attribute that corresponds to a C struct member of *note type:
     1786. T_UINT and T_ULONG. Fix a double ‘RuntimeWarning’ emitted
     when assign a negative integer value to an attribute that
     corresponds to a C struct member of type T_UINT.

   - gh-114265(17): Compiler propagates line numbers before
     optimization, leading to more optimization opportunities and
     removing the need for the ‘guarantee_lineno_for_exits’ hack.

   - gh-112529(18): The free-threaded build now has its own thread-safe
     GC implementation that uses mimalloc to find GC tracked objects.
     It is non-generational, unlike the existing GC implementation.

   - gh-114050(19): Fix segmentation fault caused by an incorrect format
     string in ‘TypeError’ exception when more than two arguments are
     passed to ‘int’.

   - gh-112354(20): The ‘END_FOR’ instruction now pops only one value.
     This is to better support side exits in loops.

   - gh-113884(21): Make *note queue.SimpleQueue: b86. thread safe when
     the GIL is disabled.

   - gh-114058(22): Implement the foundations of the Tier 2 redundancy
     eliminator.

   - gh-113939(23): frame.clear(): Clear frame.f_locals as well, and not
     only the fast locals.  This is relevant once frame.f_locals was
     accessed, which would contain also references to all the locals.

   - gh-112050(24): Convert *note collections.deque: 5df. to use
     Argument Clinic.

   - gh-112050(25): Make methods on *note collections.deque: 5df.
     thread-safe when the GIL is disabled.

   - gh-113464(26): Add an option (‘--enable-experimental-jit’ for
     ‘configure’-based builds or ‘--experimental-jit’ for
     ‘PCbuild’-based ones) to build an 'experimental' just-in-time
     compiler, based on copy-and-patch(27)

   - gh-113055(28): Make interp->obmalloc a pointer.  For interpreters
     that share state with the main interpreter, this points to the same
     static memory structure.  For interpreters with their own obmalloc
     state, it is heap allocated.  Add free_obmalloc_arenas() which will
     free the obmalloc arenas and radix tree structures for interpreters
     with their own obmalloc state.

   - gh-55664(29): Add warning when creating *note type: d71. using a
     namespace dictionary with non-string keys.  Patched by Daniel Urban
     and Furkan Onder.

   - gh-104530(30): Use native Win32 condition variables.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112087

   (2) https://github.com/python/cpython/issues/114570

   (3) https://github.com/python/cpython/issues/114695

   (4) https://github.com/python/cpython/issues/114828

   (5) https://github.com/python/cpython/issues/112069

   (6) https://github.com/python/cpython/issues/115011

   (7) https://github.com/python/cpython/issues/114887

   (8) https://github.com/python/cpython/issues/114944

   (9) https://github.com/python/cpython/issues/113462

   (10) https://github.com/python/cpython/issues/76763

   (11) https://github.com/python/cpython/issues/114806

   (12) https://github.com/python/cpython/issues/107944

   (13) https://github.com/python/cpython/issues/112529

   (14) https://github.com/python/cpython/issues/114456

   (15) https://github.com/python/cpython/issues/114083

   (16) https://github.com/python/cpython/issues/114388

   (17) https://github.com/python/cpython/issues/114265

   (18) https://github.com/python/cpython/issues/112529

   (19) https://github.com/python/cpython/issues/114050

   (20) https://github.com/python/cpython/issues/112354

   (21) https://github.com/python/cpython/issues/113884

   (22) https://github.com/python/cpython/issues/114058

   (23) https://github.com/python/cpython/issues/113939

   (24) https://github.com/python/cpython/issues/112050

   (25) https://github.com/python/cpython/issues/112050

   (26) https://github.com/python/cpython/issues/113464

   (27) https://fredrikbk.com/publications/copy-and-patch.pdf

   (28) https://github.com/python/cpython/issues/113055

   (29) https://github.com/python/cpython/issues/55664

   (30) https://github.com/python/cpython/issues/104530


File: python.info,  Node: Library<36>,  Next: Documentation<16>,  Prev: Core and Builtins<32>,  Up: Python 3 13 0 alpha 4

1.23.24.3 Library
.................

   - gh-115392(1): Fix a bug in *note doctest: 3a. where incorrect line
     numbers would be reported for decorated functions.

   - gh-114563(2): Fix several *note format(): 622. bugs when using the
     C implementation of *note Decimal: 29d.: * memory leak in some rare
     cases when using the ‘z’ format option (coerce negative 0) *
     incorrect output when applying the ‘z’ format option to type ‘F’
     (fixed-point with capital ‘NAN’ / ‘INF’) * incorrect output when
     applying the ‘#’ format option (alternate form)

   - gh-102840(3): Fix confused traceback when floordiv, mod, or divmod
     operations happens between instances of *note fractions.Fraction:
     1e7. and *note complex: 2f8.

   - gh-115165(4): Most exceptions are now ignored when attempting to
     set the ‘__orig_class__’ attribute on objects returned when calling
     *note typing: 104. generic aliases (including generic aliases
     created using *note typing.Annotated: 947.).  Previously only *note
     AttributeError: 34e. was ignored.  Patch by Dave Shawley.

   - gh-112903(5): Fix “issubclass() arg 1 must be a class” errors in
     certain cases of multiple inheritance with generic aliases
     (regression in early 3.13 alpha releases).

   - gh-115133(6): Fix tests for *note XMLPullParser: 102e. with Expat
     2.6.0.

   - gh-115059(7): ‘io.BufferedRandom.read1()’ now flushes the
     underlying write buffer.

   - gh-79382(8): Trailing ‘**’ no longer allows to match files and
     non-existing paths in recursive *note glob(): 29f.

   - gh-67837(9): Avoid race conditions in the creation of directories
     during concurrent extraction in *note tarfile: de. and *note
     zipfile: 131.

   - gh-115060(10): Speed up *note pathlib.Path.glob(): 22d. by removing
     redundant regex matching.

   - gh-97928(11): Partially revert the behavior of
     ‘tkinter.Text.count()’.  By default it preserves the behavior of
     older Python versions, except that setting ‘wantobjects’ to 0 no
     longer has effect.  Add a new parameter 'return_ints': specifying
     ‘return_ints=True’ makes ‘Text.count()’ always returning the single
     count as an integer instead of a 1-tuple or ‘None’.

   - gh-114628(12): When csv.Error is raised when handling TypeError, do
     not print the TypeError traceback.

   - gh-85984(13): Added ‘_POSIX_VDISABLE’ from C’s ‘<unistd.h>’ to
     *note termios: e1.

   - gh-114965(14): Update bundled pip to 24.0

   - gh-114959(15): *note tarfile: de. no longer ignores errors when
     trying to extract a directory on top of a file.

   - gh-114894(16): Add *note array.array.clear(): 1a2.

   - gh-114071(17): Support tuple subclasses using auto() for enum
     member value.

   - gh-109475(18): Fix support of explicit option value “–” in *note
     argparse: 6. (e.g.  ‘--option=--’).

   - gh-49766(19): Fix *note date: 1cd.-*note datetime: 1cc. comparison.
     Now the special comparison methods like ‘__eq__’ and ‘__lt__’
     return *note NotImplemented: 7d6. if one of comparands is ‘date’
     and other is ‘datetime’ instead of ignoring the time part and the
     time zone or forcefully return “not equal” or raise *note
     TypeError: 2c3.  It makes comparison of ‘date’ and ‘datetime’
     subclasses more symmetric and allows to change the default behavior
     by overriding the special comparison methods in subclasses.

   - gh-110190(20): Fix ctypes structs with array on Windows ARM64
     platform by setting ‘MAX_STRUCT_SIZE’ to 32 in stgdict.  Patch by
     Diego Russo

   - gh-114678(21): Ensure that deprecation warning for ‘N’ specifier in
     *note Decimal: 29d. format is not raised for cases where ‘N’
     appears in other places in the format specifier.  Based on patch by
     Stefan Krah.

   - gh-70303(22): Return both files and directories from *note
     pathlib.Path.glob(): 22d. if a pattern ends with “‘**’”.
     Previously only directories were returned.

   - gh-109653(23): Improve import time of *note importlib.metadata: 7a.
     and *note email.utils: 50.

   - gh-113280(24): Fix a leak of open socket in rare cases when error
     occurred in *note ssl.SSLSocket: 8f3. creation.

   - gh-77749(25): *note email.policy.EmailPolicy.fold(): 1788. now
     always encodes non-ASCII characters in headers if *note utf8: e2a.
     is false.

   - gh-83383(26): Synchronization of the *note dbm.dumb: 32. database
     is now no-op if there was no modification since opening or last
     synchronization.  The directory file for a newly created empty
     ‘dbm.dumb’ database is now created immediately after opening
     instead of deferring this until synchronizing or closing.

   - gh-91602(27): Add 'filter' keyword-only parameter to *note
     sqlite3.Connection.iterdump(): 247. for filtering database objects
     to dump.  Patch by Mariusz Felisiak.

   - gh-112451(28): Prohibit subclassing pure-Python *note
     datetime.timezone: 1103.  This is consistent with C-extension
     implementation.  Patch by Mariusz Felisiak.

   - gh-69893(29): Add the ‘close()’ method for the iterator returned by
     *note xml.etree.ElementTree.iterparse(): 273.

   - gh-109653(30): Reduce the import time of *note threading: ed.
     module by ~50%.  Patch by Daniel Hollas.

   - gh-114492(31): Make the result of *note termios.tcgetattr(): 1789.
     reproducible on Alpine Linux.  Previously it could leave a random
     garbage in some fields.

   - gh-114315(32): Make *note threading.Lock: 178a. a real class, not a
     factory function.  Add ‘__new__’ to ‘_thread.lock’ type.

   - gh-100414(33): Add *note dbm.sqlite3: 35. as a backend to *note
     dbm: 31, and make it the new default ‘dbm’ backend.  Patch by
     Raymond Hettinger and Erlend E. Aasland.

   - gh-113267(34): Revert changes in gh-106584(35) which made calls of
     ‘TestResult’ methods ‘startTest()’ and ‘stopTest()’ unbalanced.

   - gh-75128(36): Ignore an *note OSError: 41a. in
     ‘asyncio.BaseEventLoop.create_server()’ when IPv6 is available but
     the interface cannot actually support it.

   - gh-114423(37): ‘_DummyThread’ entries in ‘threading._active’ are
     now automatically removed when the related thread dies.

   - gh-114257(38): Dismiss the ‘FileNotFound’ error in *note
     ctypes.util.find_library(): d72. and just return ‘None’ on Linux.

   - gh-114321(39): Expose more platform specific constants in the *note
     fcntl: 59. module on Linux, macOS, FreeBSD and NetBSD.

   - gh-114328(40): The *note tty.setcbreak(): 178b. and new *note
     tty.cfmakecbreak(): 178c. no longer clears the terminal input ICRLF
     flag.  This fixes a regression introduced in 3.12 that no longer
     matched how OSes define cbreak mode in their ‘stty(1)’ manual
     pages.

   - gh-114281(41): Remove type hints from ‘Lib/asyncio/staggered.py’.
     The annotations in the typeshed(42) project should be used instead.

   - gh-101438(43): Avoid reference cycle in ElementTree.iterparse.  The
     iterator returned by ‘ElementTree.iterparse’ may hold on to a file
     descriptor.  The reference cycle prevented prompt clean-up of the
     file descriptor if the returned iterator was not exhausted.

   - gh-114198(44): The signature for the ‘__replace__’ method on *note
     dataclasses: 2f. now has the first argument named ‘self’, rather
     than ‘obj’.

   - gh-104522(45): *note OSError: 41a. raised when run a subprocess now
     only has 'filename' attribute set to 'cwd' if the error was caused
     by a failed attempt to change the current directory.

   - gh-114149(46): Enum: correctly handle tuple subclasses in custom
     ‘__new__’.

   - gh-83648(47): Support deprecation of options, positional arguments
     and subcommands in *note argparse: 6.

   - gh-114087(48): Speed up ‘dataclasses.asdict’ up to 1.35x.

   - gh-109534(49): Fix a reference leak in
     ‘asyncio.selector_events.BaseSelectorEventLoop’ when SSL handshakes
     fail.  Patch contributed by Jamie Phan.

   - gh-79634(50): Accept *note path-like objects: 2a0. as patterns in
     *note pathlib.Path.glob(): 22d. and *note rglob(): 22e.

   - gh-112202(51): Ensure that a *note asyncio.Condition.notify():
     178d. call does not get lost if the awakened ‘Task’ is
     simultaneously cancelled or encounters any other error.

   - gh-113951(52): Fix the behavior of ‘tag_unbind()’ methods of
     ‘tkinter.Text’ and ‘tkinter.Canvas’ classes with three arguments.
     Previously, ‘widget.tag_unbind(tag, sequence, funcid)’ destroyed
     the current binding for 'sequence', leaving 'sequence' unbound, and
     deleted the 'funcid' command.  Now it removes only 'funcid' from
     the binding for 'sequence', keeping other commands, and deletes the
     'funcid' command.  It leaves 'sequence' unbound only if 'funcid'
     was the last bound command.

   - gh-97959(53): Fix rendering class methods, bound methods, method
     and function aliases in *note pydoc: b5.  Class methods no longer
     have “method of builtins.type instance” note.  Corresponding notes
     are now added for class and unbound methods.  Method and function
     aliases now have references to the module or the class where the
     origin was defined if it differs from the current.  Bound methods
     are now listed in the static methods section.  Methods of builtin
     classes are now supported as well as methods of Python classes.

   - gh-113796(54): Add more validation checks in the *note csv.Dialect:
     178e. constructor.  *note ValueError: 202. is now raised if the
     same character is used in different roles.

   - gh-113732(55): Fix support of *note QUOTE_NOTNULL: 487. and *note
     QUOTE_STRINGS: 488. in *note csv.reader(): 489.

   - gh-113225(56): Speed up *note pathlib.Path.walk(): 4ab. by using
     *note os.DirEntry.path: 178f. where possible.

   - gh-89039(57): When replace() method is called on a subclass of
     datetime, date or time, properly call derived constructor.
     Previously, only the base class’s constructor was called.

     Also, make sure to pass non-zero fold values when creating
     subclasses in various methods.  Previously, fold was silently
     ignored.

   - gh-112919(58): Speed-up *note datetime.datetime.replace(): 151a,
     *note datetime.date.replace(): 1790. and *note
     datetime.time.replace(): 1791.

   - gh-59013(59): Set breakpoint on the first executable line of the
     function, instead of the line of function definition when the user
     do ‘break func’ using *note pdb: a5.

   - gh-112343(60): Improve handling of pdb convenience variables to
     avoid replacing string contents.

   - gh-112240(61): Add option to calendar module CLI to specify the
     weekday to start each week.  Patch by Steven Ward.

   - gh-111741(62): Recognise ‘image/webp’ as a standard format in the
     *note mimetypes: 8f. module.

   - gh-43457(63): Fix the *note tkinter: f0. widget method
     ‘wm_attributes()’.  It now accepts the attribute name without the
     minus prefix to get window attributes and allows to specify
     attributes and values to set as keyword arguments.  Add new
     optional keyword argument 'return_python_dict': calling
     ‘w.wm_attributes(return_python_dict=True)’ returns the attributes
     as a dict instead of a tuple.  Calling ‘w.wm_attributes()’ now
     returns a tuple instead of string if 'wantobjects' was set to 0.

   - gh-82626(64): Many functions now emit a warning if a boolean value
     is passed as a file descriptor argument.

   - gh-111051(65): Added check for file modification during debugging
     with *note pdb: a5.

   - gh-110345(66): Show the Tcl/Tk patchlevel (rather than version) in
     ‘tkinter._test()’.

   - gh-38807(67): Fix race condition in *note trace: fd.  Instead of
     checking if a directory exists and creating it, directly call *note
     os.makedirs(): 21e. with the kwarg ‘exist_ok=True’.

   - gh-75705(68): Set unixfrom envelope in *note mailbox.mbox: 1792.
     and *note mailbox.MMDF: 1793.

   - gh-106233(69): Fix stacklevel in ‘InvalidTZPathWarning’ during
     *note zoneinfo: 134. module import.

   - gh-105102(70): Allow *note ctypes.Union: 1794. to be nested in
     *note ctypes.Structure: 1d4. when the system endianness is the
     opposite of the classes.

   - gh-104282(71): Fix null pointer dereference in
     ‘lzma._decode_filter_properties()’ due to improper handling of BCJ
     filters with properties of zero length.  Patch by Radislav
     Chugunov.

   - gh-96471(72): Add *note queue.Queue: 13e1. termination with *note
     shutdown(): 23a.

   - gh-101599(73): Changed argparse flag options formatting to remove
     redundancy.

   - gh-85984(74): Add POSIX pseudo-terminal functions *note
     os.posix_openpt(): 1795, *note os.grantpt(): 1796, *note
     os.unlockpt(): 1797, and *note os.ptsname(): 1798.

   - gh-102512(75): When *note os.fork(): 197. is called from a foreign
     thread (aka ‘_DummyThread’), the type of the thread in a child
     process is changed to ‘_MainThread’.  Also changed its name and
     daemonic status, it can be now joined.

   - gh-88569(76): Add *note os.path.isreserved(): 223, which identifies
     reserved pathnames such as “NUL”, “AUX” and “CON”.  This function
     is only available on Windows.

     Deprecate *note pathlib.PurePath.is_reserved(): 2a6.

   - bpo-38364(77): The ‘inspect’ functions ‘isgeneratorfunction’,
     ‘iscoroutinefunction’, ‘isasyncgenfunction’ now support
     ‘functools.partialmethod’ wrapped functions the same way they
     support ‘functools.partial’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115392

   (2) https://github.com/python/cpython/issues/114563

   (3) https://github.com/python/cpython/issues/102840

   (4) https://github.com/python/cpython/issues/115165

   (5) https://github.com/python/cpython/issues/112903

   (6) https://github.com/python/cpython/issues/115133

   (7) https://github.com/python/cpython/issues/115059

   (8) https://github.com/python/cpython/issues/79382

   (9) https://github.com/python/cpython/issues/67837

   (10) https://github.com/python/cpython/issues/115060

   (11) https://github.com/python/cpython/issues/97928

   (12) https://github.com/python/cpython/issues/114628

   (13) https://github.com/python/cpython/issues/85984

   (14) https://github.com/python/cpython/issues/114965

   (15) https://github.com/python/cpython/issues/114959

   (16) https://github.com/python/cpython/issues/114894

   (17) https://github.com/python/cpython/issues/114071

   (18) https://github.com/python/cpython/issues/109475

   (19) https://github.com/python/cpython/issues/49766

   (20) https://github.com/python/cpython/issues/110190

   (21) https://github.com/python/cpython/issues/114678

   (22) https://github.com/python/cpython/issues/70303

   (23) https://github.com/python/cpython/issues/109653

   (24) https://github.com/python/cpython/issues/113280

   (25) https://github.com/python/cpython/issues/77749

   (26) https://github.com/python/cpython/issues/83383

   (27) https://github.com/python/cpython/issues/91602

   (28) https://github.com/python/cpython/issues/112451

   (29) https://github.com/python/cpython/issues/69893

   (30) https://github.com/python/cpython/issues/109653

   (31) https://github.com/python/cpython/issues/114492

   (32) https://github.com/python/cpython/issues/114315

   (33) https://github.com/python/cpython/issues/100414

   (34) https://github.com/python/cpython/issues/113267

   (35) https://github.com/python/cpython/issues/106584

   (36) https://github.com/python/cpython/issues/75128

   (37) https://github.com/python/cpython/issues/114423

   (38) https://github.com/python/cpython/issues/114257

   (39) https://github.com/python/cpython/issues/114321

   (40) https://github.com/python/cpython/issues/114328

   (41) https://github.com/python/cpython/issues/114281

   (42) https://github.com/python/typeshed

   (43) https://github.com/python/cpython/issues/101438

   (44) https://github.com/python/cpython/issues/114198

   (45) https://github.com/python/cpython/issues/104522

   (46) https://github.com/python/cpython/issues/114149

   (47) https://github.com/python/cpython/issues/83648

   (48) https://github.com/python/cpython/issues/114087

   (49) https://github.com/python/cpython/issues/109534

   (50) https://github.com/python/cpython/issues/79634

   (51) https://github.com/python/cpython/issues/112202

   (52) https://github.com/python/cpython/issues/113951

   (53) https://github.com/python/cpython/issues/97959

   (54) https://github.com/python/cpython/issues/113796

   (55) https://github.com/python/cpython/issues/113732

   (56) https://github.com/python/cpython/issues/113225

   (57) https://github.com/python/cpython/issues/89039

   (58) https://github.com/python/cpython/issues/112919

   (59) https://github.com/python/cpython/issues/59013

   (60) https://github.com/python/cpython/issues/112343

   (61) https://github.com/python/cpython/issues/112240

   (62) https://github.com/python/cpython/issues/111741

   (63) https://github.com/python/cpython/issues/43457

   (64) https://github.com/python/cpython/issues/82626

   (65) https://github.com/python/cpython/issues/111051

   (66) https://github.com/python/cpython/issues/110345

   (67) https://github.com/python/cpython/issues/38807

   (68) https://github.com/python/cpython/issues/75705

   (69) https://github.com/python/cpython/issues/106233

   (70) https://github.com/python/cpython/issues/105102

   (71) https://github.com/python/cpython/issues/104282

   (72) https://github.com/python/cpython/issues/96471

   (73) https://github.com/python/cpython/issues/101599

   (74) https://github.com/python/cpython/issues/85984

   (75) https://github.com/python/cpython/issues/102512

   (76) https://github.com/python/cpython/issues/88569

   (77) https://bugs.python.org/issue?@action=redirect&bpo=38364


File: python.info,  Node: Documentation<16>,  Next: Tests<18>,  Prev: Library<36>,  Up: Python 3 13 0 alpha 4

1.23.24.4 Documentation
.......................

   - gh-115233(1): Fix an example for *note LoggerAdapter: 133e. in the
     Logging Cookbook.

   - gh-114123(2): Move the *note csv: 29. module docstring to the ‘csv’
     module instead of reexporting it from the internal ‘_csv’ module,
     and remove ‘__doc__’ from ‘csv.__all__’.

     Move ‘csv.__version__’ to the ‘csv’ module instead of reexporting
     it from the internal ‘_csv’ module, and remove ‘__version__’ from
     ‘csv.__all__’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115233

   (2) https://github.com/python/cpython/issues/114123


File: python.info,  Node: Tests<18>,  Next: Build<18>,  Prev: Documentation<16>,  Up: Python 3 13 0 alpha 4

1.23.24.5 Tests
...............

   - gh-114099(1): Added test exclusions required to run the test suite
     on iOS.

   - gh-105089(2): Fix
     ‘test.test_zipfile.test_core.TestWithDirectory.test_create_directory_with_write’
     test in AIX by doing a bitwise AND of 0xFFFF on mode , so that it
     will be in sync with ‘zinfo.external_attr’

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114099

   (2) https://github.com/python/cpython/issues/105089


File: python.info,  Node: Build<18>,  Next: Windows<16>,  Prev: Tests<18>,  Up: Python 3 13 0 alpha 4

1.23.24.6 Build
...............

   - gh-115167(1): Avoid vendoring ‘vcruntime140_threads.dll’ when
     building with Visual Studio 2022 version 17.8.

   - gh-113632(2): Promote WASI to a tier 2 platform and drop Emscripten
     from tier 3 in configure.ac.

   - gh-114099(3): configure and Makefile were refactored to accommodate
     framework builds on Apple platforms other than macOS.

   - gh-114875(4): Add ‘getgrent()’ as a prerequisite for building the
     *note grp: 66. module.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115167

   (2) https://github.com/python/cpython/issues/113632

   (3) https://github.com/python/cpython/issues/114099

   (4) https://github.com/python/cpython/issues/114875


File: python.info,  Node: Windows<16>,  Next: macOS<11>,  Prev: Build<18>,  Up: Python 3 13 0 alpha 4

1.23.24.7 Windows
.................

   - gh-115049(1): Fixes ‘py.exe’ launcher failing when run as users
     without user profiles.

   - gh-115009(2): Update Windows installer to use SQLite 3.45.1.

   - gh-109991(3): Update Windows build to use OpenSSL 3.0.13.

   - gh-111239(4): Update Windows builds to use zlib v1.3.1.

   - gh-100107(5): The ‘py.exe’ launcher will no longer attempt to run
     the Microsoft Store redirector when launching a script containing a
     ‘/usr/bin/env’ shebang

   - gh-112984(6): Adds free-threaded binaries to Windows installer as
     an optional component.

   - gh-89240(7): Allows *note multiprocessing: 94. to create pools of
     greater than 62 processes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115049

   (2) https://github.com/python/cpython/issues/115009

   (3) https://github.com/python/cpython/issues/109991

   (4) https://github.com/python/cpython/issues/111239

   (5) https://github.com/python/cpython/issues/100107

   (6) https://github.com/python/cpython/issues/112984

   (7) https://github.com/python/cpython/issues/89240


File: python.info,  Node: macOS<11>,  Next: IDLE<14>,  Prev: Windows<16>,  Up: Python 3 13 0 alpha 4

1.23.24.8 macOS
...............

   - gh-115009(1): Update macOS installer to use SQLite 3.45.1.

   - gh-109991(2): Update macOS installer to use OpenSSL 3.0.13.

   - gh-114490(3): Add Mach-O linkage support for *note
     platform.architecture(): 179e.

   - gh-87804(4): On macOS the result of ‘os.statvfs’ and ‘os.fstatvfs’
     now correctly report the size of very large disks, in previous
     versions the reported number of blocks was wrong for disks with at
     least 2**32 blocks.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115009

   (2) https://github.com/python/cpython/issues/109991

   (3) https://github.com/python/cpython/issues/114490

   (4) https://github.com/python/cpython/issues/87804


File: python.info,  Node: IDLE<14>,  Next: Tools/Demos<10>,  Prev: macOS<11>,  Up: Python 3 13 0 alpha 4

1.23.24.9 IDLE
..............

   - gh-96905(1): In idlelib code, stop redefining built-ins ‘dict’ and
     ‘object’.

   - gh-103820(2): Revise IDLE bindings so that events from mouse button
     4/5 on non-X11 windowing systems (i.e.  Win32 and Aqua) are not
     mistaken for scrolling.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96905

   (2) https://github.com/python/cpython/issues/103820


File: python.info,  Node: Tools/Demos<10>,  Next: C API<18>,  Prev: IDLE<14>,  Up: Python 3 13 0 alpha 4

1.23.24.10 Tools/Demos
......................

   - gh-113516(1): Don’t set ‘LDSHARED’ when building for WASI.

   - gh-109991(2): Update GitHub CI workflows to use OpenSSL 3.0.13 and
     multissltests to use 1.1.1w, 3.0.13, 3.1.5, and 3.2.1.

   - gh-115015(3): Fix a bug in Argument Clinic that generated incorrect
     code for methods with no parameters that use the *note METH_METHOD
     | METH_FASTCALL | METH_KEYWORDS: 17a1. calling convention.  Only
     the positional parameter count was checked; any keyword argument
     passed would be silently accepted.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113516

   (2) https://github.com/python/cpython/issues/109991

   (3) https://github.com/python/cpython/issues/115015


File: python.info,  Node: C API<18>,  Prev: Tools/Demos<10>,  Up: Python 3 13 0 alpha 4

1.23.24.11 C API
................

   - gh-111140(1): Adds *note PyLong_AsNativeBytes(): 364, *note
     PyLong_FromNativeBytes(): 365. and *note
     PyLong_FromUnsignedNativeBytes(): 366. functions.

   - gh-114685(2): *note PyBuffer_FillInfo(): 763. now raises a *note
     SystemError: 578. if called with *note PyBUF_READ: 17a3. or *note
     PyBUF_WRITE: 17a4. as flags.  These flags should only be used with
     the ‘PyMemoryView_*’ C API.

   - gh-114685(3): *note PyObject_GetBuffer(): 39c. now raises a *note
     SystemError: 578. if called with *note PyBUF_READ: 17a3. or *note
     PyBUF_WRITE: 17a4. as flags.  These flags should only be used with
     the ‘PyMemoryView_*’ C API.

   - gh-114626(4): Add ‘PyCFunctionFast’ and
     ‘PyCFunctionFastWithKeywords’ typedefs (identical to the existing
     ‘_PyCFunctionFast’ and ‘_PyCFunctionFastWithKeywords’ typedefs,
     just without a leading ‘_’ prefix).

   - gh-114329(5): Add *note PyList_GetItemRef(): 35c, which is similar
     to *note PyList_GetItem(): 35d. but returns a *note strong
     reference: 33e. instead of a *note borrowed reference: 33f.

   - gh-110850(6): Add PyTime C API:

        * *note PyTime_t: 32e. type.

        * *note PyTime_MIN: 32f. and *note PyTime_MAX: 330. constants.

        * *note PyTime_AsSecondsDouble(): 331, *note PyTime_Monotonic():
          332, *note PyTime_PerfCounter(): 334, and *note PyTime_Time():
          336. functions.

     Patch by Victor Stinner.

   - gh-112066(7): Add *note PyDict_SetDefaultRef(): 340.: insert a key
     and value into a dictionary if the key is not already present.
     This is similar to *note dict.setdefault(): 10b7, but returns an
     integer value indicating if the key was already present.  It is
     also similar to *note PyDict_SetDefault(): 341, but returns a
     strong reference instead of a borrowed reference.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111140

   (2) https://github.com/python/cpython/issues/114685

   (3) https://github.com/python/cpython/issues/114685

   (4) https://github.com/python/cpython/issues/114626

   (5) https://github.com/python/cpython/issues/114329

   (6) https://github.com/python/cpython/issues/110850

   (7) https://github.com/python/cpython/issues/112066


File: python.info,  Node: Python 3 13 0 alpha 3,  Next: Python 3 13 0 alpha 2,  Prev: Python 3 13 0 alpha 4,  Up: Changelog

1.23.25 Python 3.13.0 alpha 3
-----------------------------

'Release date: 2024-01-17'

* Menu:

* Security: Security<17>.
* Core and Builtins: Core and Builtins<33>.
* Library: Library<37>.
* Documentation: Documentation<17>.
* Tests: Tests<19>.
* Build: Build<19>.
* Windows: Windows<17>.
* macOS: macOS<12>.
* IDLE: IDLE<15>.
* C API: C API<19>.


File: python.info,  Node: Security<17>,  Next: Core and Builtins<33>,  Up: Python 3 13 0 alpha 3

1.23.25.1 Security
..................

   - gh-113659(1): Skip ‘.pth’ files with names starting with a dot or
     hidden file attribute.

   - gh-112302(2): Created a Software Bill-of-Materials document and
     tooling for tracking dependencies.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113659

   (2) https://github.com/python/cpython/issues/112302


File: python.info,  Node: Core and Builtins<33>,  Next: Library<37>,  Prev: Security<17>,  Up: Python 3 13 0 alpha 3

1.23.25.2 Core and Builtins
...........................

   - gh-107901(1): Compiler duplicates basic blocks that have an eval
     breaker check, no line number, and multiple predecessors.

   - gh-107901(2): A jump leaving an exception handler back to normal
     code no longer checks the eval breaker.

   - gh-113655(3): Set the C recursion limit to 4000 on Windows, and
     10000 on Linux/OSX. This seems to be near the sweet spot to
     maintain safety, but not compromise backwards compatibility.

   - gh-113710(4): Add typed stack effects to the interpreter DSL, along
     with various instruction annotations.

   - gh-77046(5): On Windows, file descriptors wrapping Windows handles
     are now created non inheritable by default ( PEP 446(6)).  Patch by
     Zackery Spytz and Victor Stinner.

   - gh-113853(7): Guarantee that all executors make progress.  This
     then guarantees that tier 2 execution always makes progress.

   - gh-113753(8): Fix an issue where the finalizer of ‘PyAsyncGenASend’
     objects might not be called if they were allocated from a free
     list.

   - gh-107901(9): Compiler changed so that synthetic jumps which are
     not at loop end no longer check the eval breaker.

   - gh-113703(10): Fix a regression in the *note codeop: 1c. module
     that was causing it to incorrectly identify incomplete f-strings.
     Patch by Pablo Galindo

   - gh-89811(11): Check for a valid ‘tp_version_tag’ before performing
     bytecode specializations that rely on this value being usable.

   - gh-111488(12): Changed error message in case of no ‘in’ keyword
     after ‘for’ in list comprehensions

   - gh-113657(13): Fix an issue that caused important instruction
     pointer updates to be optimized out of tier two traces.

   - gh-113603(14): Fixed bug where a redundant NOP is not removed,
     causing an assertion to fail in the compiler in debug mode.

   - gh-113602(15): Fix an error that was causing the parser to try to
     overwrite existing errors and crashing in the process.  Patch by
     Pablo Galindo

   - gh-113486(16): No longer issue spurious ‘PY_UNWIND’ events for
     optimized calls to classes.

   - gh-113297(17): Fix segfault in the compiler on with statement with
     19 context managers.

   - gh-113212(18): Improve *note super: 4de. error messages.

   - gh-111375(19): Only use ‘NULL’ in the exception stack to indicate
     an exception was handled.  Patch by Carey Metcalfe.

   - gh-112215(20): Increase the C recursion limit by a factor of 3 for
     non-debug builds, except for webassembly and s390 platforms which
     are unchanged.  This mitigates some regressions in 3.12 with deep
     recursion mixing builtin (C) and Python code.

   - gh-113054(21): Fixed bug where a redundant NOP is not removed,
     causing an assertion to fail in the compiler in debug mode.

   - gh-106905(22): Use per AST-parser state rather than global state to
     track recursion depth within the AST parser to prevent potential
     race condition due to simultaneous parsing.

     The issue primarily showed up in 3.11 by multithreaded users of
     *note ast.parse(): 1a8.  In 3.12 a change to when garbage
     collection can be triggered prevented the race condition from
     occurring.

   - gh-108866(23): Change the API and contract of ‘_PyExecutorObject’
     to return the next_instr pointer, instead of the frame, and to
     always execute at least one instruction.

   - gh-90350(24): Optimize builtin functions *note min(): f3f. and
     *note max(): f40.

   - gh-112943(25): Correctly compute end column offsets for multiline
     tokens in the *note tokenize: fb. module.  Patch by Pablo Galindo

   - gh-112125(26): Fix ‘None.__ne__(None)’ returning ‘NotImplemented’
     instead of ‘False’.

   - gh-74616(27): *note input(): 1320. now raises a ValueError when
     output on the terminal if the prompt contains embedded null
     characters instead of silently truncating it.

   - gh-112716(28): Fix SystemError in the ‘import’ statement and in
     ‘__reduce__()’ methods of builtin types when ‘__builtins__’ is not
     a dict.

   - gh-112730(29): Use color to highlight error locations in
     tracebacks.  Patch by Pablo Galindo

   - gh-112625(30): Fixes a bug where a bytearray object could be
     cleared while iterating over an argument in the ‘bytearray.join()’
     method that could result in reading memory after it was freed.

   - gh-112660(31): Do not clear unexpected errors during formatting
     error messages for ImportError and AttributeError for modules.

   - gh-105967(32): Workaround a bug in Apple’s macOS platform zlib
     library where *note zlib.crc32(): 17a8. and *note binascii.crc32():
     17a9. could produce incorrect results on multi-gigabyte inputs.
     Including when using *note zipfile: 131. on zips containing large
     data.

   - gh-95754(33): Provide a better error message when accessing invalid
     attributes on partially initialized modules.  The origin of the
     module being accessed is now included in the message to help with
     the common issue of shadowing other modules.

   - gh-112217(34): Add check for the type of ‘__cause__’ returned from
     calling the type ‘T’ in ‘raise from T’.

   - gh-111058(35): Change coro.cr_frame/gen.gi_frame to return ‘None’
     after the coroutine/generator has been closed.  This fixes a bug
     where *note getcoroutinestate(): e4b. and *note
     getgeneratorstate(): 127c. return the wrong state for a closed
     coroutine/generator.

   - gh-112388(36): Fix an error that was causing the parser to try to
     overwrite tokenizer errors.  Patch by pablo Galindo

   - gh-112387(37): Fix error positions for decoded strings with
     backwards tokenize errors.  Patch by Pablo Galindo

   - gh-99606(38): Make code generated for an empty f-string identical
     to the code of an empty normal string.

   - gh-112367(39): Avoid undefined behaviour when using the perf
     trampolines by not freeing the code arenas until shutdown.  Patch
     by Pablo Galindo

   - gh-112320(40): The Tier 2 translator now tracks the confidence
     level for staying “on trace” (i.e.  not exiting back to the Tier 1
     interpreter) for branch instructions based on the number of bits
     set in the branch “counter”.  Trace translation ends when the
     confidence drops below 1/3rd.

   - gh-109598(41): *note PyComplex_RealAsDouble(): 17aa./*note
     PyComplex_ImagAsDouble(): 17ab. now tries to convert an object to a
     *note complex: 2f8. instance using its ‘__complex__()’ method
     before falling back to the ‘__float__()’ method.  Patch by Sergey B
     Kirpichev.

   - gh-94606(42): Fix UnicodeEncodeError when
     ‘email.message.get_payload()’ reads a message with a Unicode
     surrogate character and the message content is not well-formed for
     surrogateescape encoding.  Patch by Sidney Markowitz.

   - bpo-21861(43): Use the object’s actual class name in
     ‘_io.FileIO.__repr__()’, ‘_io._WindowsConsoleIO()’ and
     ‘_io.TextIOWrapper.__repr__()’, to make these methods subclass
     friendly.

   - bpo-45369(44): Remove LibreSSL workarounds as per PEP 644(45).

   - bpo-34392(46): Added *note sys._is_interned(): 250.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/107901

   (2) https://github.com/python/cpython/issues/107901

   (3) https://github.com/python/cpython/issues/113655

   (4) https://github.com/python/cpython/issues/113710

   (5) https://github.com/python/cpython/issues/77046

   (6) https://peps.python.org/pep-0446/

   (7) https://github.com/python/cpython/issues/113853

   (8) https://github.com/python/cpython/issues/113753

   (9) https://github.com/python/cpython/issues/107901

   (10) https://github.com/python/cpython/issues/113703

   (11) https://github.com/python/cpython/issues/89811

   (12) https://github.com/python/cpython/issues/111488

   (13) https://github.com/python/cpython/issues/113657

   (14) https://github.com/python/cpython/issues/113603

   (15) https://github.com/python/cpython/issues/113602

   (16) https://github.com/python/cpython/issues/113486

   (17) https://github.com/python/cpython/issues/113297

   (18) https://github.com/python/cpython/issues/113212

   (19) https://github.com/python/cpython/issues/111375

   (20) https://github.com/python/cpython/issues/112215

   (21) https://github.com/python/cpython/issues/113054

   (22) https://github.com/python/cpython/issues/106905

   (23) https://github.com/python/cpython/issues/108866

   (24) https://github.com/python/cpython/issues/90350

   (25) https://github.com/python/cpython/issues/112943

   (26) https://github.com/python/cpython/issues/112125

   (27) https://github.com/python/cpython/issues/74616

   (28) https://github.com/python/cpython/issues/112716

   (29) https://github.com/python/cpython/issues/112730

   (30) https://github.com/python/cpython/issues/112625

   (31) https://github.com/python/cpython/issues/112660

   (32) https://github.com/python/cpython/issues/105967

   (33) https://github.com/python/cpython/issues/95754

   (34) https://github.com/python/cpython/issues/112217

   (35) https://github.com/python/cpython/issues/111058

   (36) https://github.com/python/cpython/issues/112388

   (37) https://github.com/python/cpython/issues/112387

   (38) https://github.com/python/cpython/issues/99606

   (39) https://github.com/python/cpython/issues/112367

   (40) https://github.com/python/cpython/issues/112320

   (41) https://github.com/python/cpython/issues/109598

   (42) https://github.com/python/cpython/issues/94606

   (43) https://bugs.python.org/issue?@action=redirect&bpo=21861

   (44) https://bugs.python.org/issue?@action=redirect&bpo=45369

   (45) https://peps.python.org/pep-0644/

   (46) https://bugs.python.org/issue?@action=redirect&bpo=34392


File: python.info,  Node: Library<37>,  Next: Documentation<17>,  Prev: Core and Builtins<33>,  Up: Python 3 13 0 alpha 3

1.23.25.3 Library
.................

   - gh-114077(1): Fix possible *note OverflowError: 888. in *note
     socket.socket.sendfile(): e91. when pass 'count' larger than 2 GiB
     on 32-bit platform.

   - gh-111803(2): *note plistlib: ab. now supports loading more deeply
     nested lists in binary format.

   - gh-114014(3): Fixed a bug in *note fractions.Fraction: 1e7. where
     an invalid string using ‘d’ in the decimals part creates a
     different error compared to other invalid letters/characters.
     Patch by Jeremiah Gabriel Pascual.

   - gh-108364(4): *note sqlite3.Connection.iterdump(): 247. now ensures
     that foreign key support is disabled before dumping the database
     schema, if there is any foreign key violation.  Patch by Erlend E.
     Aasland and Mariusz Felisiak.

   - gh-113971(5): The *note zipfile.ZipInfo: d32. previously protected
     ‘._compresslevel’ attribute has been made public as
     ‘.compress_level’ with the old ‘_compresslevel’ name remaining
     available as a property to retain compatibility.

   - gh-113877(6): Fix *note tkinter: f0. method ‘winfo_pathname()’ on
     64-bit Windows.

   - gh-113868(7): Added *note mmap.MAP_NORESERVE: 17ad, *note
     mmap.MAP_NOEXTEND: 17ae, *note mmap.MAP_HASSEMAPHORE: 17af, *note
     mmap.MAP_NOCACHE: 17b0, *note mmap.MAP_JIT: 17b1, *note
     mmap.MAP_RESILIENT_CODESIGN: 17b2, *note mmap.MAP_RESILIENT_MEDIA:
     17b3, *note mmap.MAP_32BIT: 17b4, *note
     mmap.MAP_TRANSLATED_ALLOW_EXECUTE: 17b5, *note mmap.MAP_UNIX03:
     17b6. and *note mmap.MAP_TPRO: 17b7.  All of them are ‘mmap(2)’
     flags on macOS.

   - gh-113848(8): *note asyncio.TaskGroup(): 1b5. and *note
     asyncio.timeout(): 601. context managers now handle *note
     CancelledError: 1b8. subclasses as well as exact ‘CancelledError’.

   - gh-113661(9): unittest runner: Don’t exit 5 if tests were skipped.
     The intention of exiting 5 was to detect issues where the test
     suite wasn’t discovered at all.  If we skipped tests, it was
     correctly discovered.

   - gh-96037(10): Insert *note TimeoutError: 83b. in the context of the
     exception that was raised during exiting an expired *note
     asyncio.timeout(): 601. block.

   - gh-113781(11): Silence unraisable AttributeError when warnings are
     emitted during Python finalization.

   - gh-113238(12): Add ‘Anchor’ to ‘importlib.resources’ (in order for
     the code to comply with the documentation)

   - gh-111693(13): *note asyncio.Condition.wait(): 17b8. now re-raises
     the same ‘CancelledError’ instance that may have caused it to be
     interrupted.  Fixed race condition in *note
     asyncio.Semaphore.acquire(): 17b9. when interrupted with a
     ‘CancelledError’.

   - gh-113791(14): Add ‘CLOCK_MONOTONIC_RAW_APPROX’ and
     ‘CLOCK_UPTIME_RAW_APPROX’ to *note time: ee. on macOS. These are
     clocks available on macOS 10.12 or later.

   - gh-112932(15): Restore the ability for *note zipfile: 131. to
     ‘extractall’ from zip files with a “/” directory entry in them as
     is commonly added to zips by some wiki or bug tracker data
     exporters.

   - gh-113568(16): Raise deprecation warnings from *note
     pathlib.PurePath: 4a9. and not its private base class
     ‘PurePathBase’.

   - gh-113594(17): Fix *note UnicodeEncodeError: 67a. in *note email:
     3b. when re-fold lines that contain unknown-8bit encoded part
     followed by non-unknown-8bit encoded part.

   - gh-113538(18): In ‘asyncio.StreamReaderProtocol.connection_made()’,
     there is callback that logs an error if the task wrapping the
     “connected callback” fails.  This callback would itself fail if the
     task was cancelled.  Prevent this by checking whether the task was
     cancelled first.  If so, close the transport but don’t log an
     error.

   - gh-113626(19): Add support for the 'allow_code' argument in the
     *note marshal: 8d. module.  Passing ‘allow_code=False’ prevents
     serialization and de-serialization of code objects which is
     incompatible between Python versions.

   - gh-85567(20): Fix resource warnings for unclosed files in *note
     pickle: a6. and *note pickletools: a7. command line interfaces.

   - gh-113537(21): Support loads ‘str’ in *note plistlib.loads(): 95a.

   - gh-89850(22): Add default implementations of *note
     pickle.Pickler.persistent_id(): 16a5. and *note
     pickle.Unpickler.persistent_load(): 16ac. methods in the C
     implementation.  Calling ‘super().persistent_id()’ and
     ‘super().persistent_load()’ in subclasses of the C implementation
     of *note pickle.Pickler: a2b. and *note pickle.Unpickler: 15c4.
     classes no longer causes infinite recursion.

   - gh-113569(23): Indicate if there were no actual calls in unittest
     *note assert_has_calls(): 17ba. failure.

   - gh-101225(24): Increase the backlog for *note
     multiprocessing.connection.Listener: 17bb. objects created by
     ‘multiprocessing.manager’ and ‘multiprocessing.resource_sharer’ to
     significantly reduce the risk of getting a connection refused error
     when creating a *note multiprocessing.connection.Connection: 1124.
     to them.

   - gh-113568(25): Raise audit events from *note pathlib.Path: 229. and
     not its private base class ‘PathBase’.

   - gh-113543(26): Make sure that ‘webbrowser.MacOSXOSAScript’ sends
     ‘webbrowser.open’ audit event.

   - gh-113028(27): When a second reference to a string appears in the
     input to *note pickle: a6, and the Python implementation is in use,
     we are guaranteed that a single copy gets pickled and a single
     object is shared when reloaded.  Previously, in protocol 0, when a
     string contained certain characters (e.g.  newline) it resulted in
     duplicate objects.

   - gh-113421(28): Fix multiprocessing logger for ‘%(filename)s’.

   - gh-111784(29): Fix segfaults in the ‘_elementtree’ module.  Fix
     first segfault during deallocation of ‘_elementtree.XMLParser’
     instances by keeping strong reference to ‘pyexpat’ module in module
     state for capsule lifetime.  Fix second segfault which happens in
     the same deallocation process by keeping strong reference to
     ‘_elementtree’ module in ‘XMLParser’ structure for ‘_elementtree’
     module lifetime.

   - gh-113407(30): Fix import of *note unittest.mock: 107. when CPython
     is built without docstrings.

   - gh-113320(31): Fix regression in Python 3.12 where *note Protocol:
     264. classes that were not marked as *note runtime-checkable: 446.
     would be unnecessarily introspected, potentially causing exceptions
     to be raised if the protocol had problematic members.  Patch by
     Alex Waygood.

   - gh-53502(32): Add a new option ‘aware_datetime’ in *note plistlib:
     ab. to loads or dumps aware datetime.

   - gh-113358(33): Fix rendering tracebacks with exceptions with a
     broken __getattr__

   - gh-113214(34): Fix an ‘AttributeError’ during asyncio SSL protocol
     aborts in SSL-over-SSL scenarios.

   - gh-113246(35): Update bundled pip to 23.3.2.

   - gh-87264(36): Fixed tarfile list() method to show file type.

   - gh-112182(37): ‘asyncio.futures.Future.set_exception()’ now
     transforms *note StopIteration: c1b. into *note RuntimeError: 195.
     instead of hanging or other misbehavior.  Patch contributed by
     Jamie Phan.

   - gh-113225(38): Speed up *note pathlib.Path.glob(): 22d. by using
     *note os.DirEntry.path: 178f. where possible.

   - gh-113149(39): Improve error message when a JSON array or object
     contains a trailing comma.  Patch by Carson Radtke.

   - gh-113117(40): The *note subprocess: d6. module can now use the
     *note os.posix_spawn(): 220. function with ‘close_fds=True’ on
     platforms where ‘posix_spawn_file_actions_addclosefrom_np’ is
     available.  Patch by Jakub Kulik.

   - gh-113199(41): Make ‘http.client.HTTPResponse.read1’ and
     ‘http.client.HTTPResponse.readline’ close IO after reading all data
     when content length is known.  Patch by Illia Volochii.

   - gh-113191(42): Add support of *note os.fchmod(): 21c. and a file
     descriptor in *note os.chmod(): 21b. on Windows.

   - gh-113188(43): Fix *note shutil.copymode(): 17bc. and *note
     shutil.copystat(): 1172. on Windows.  Previously they worked
     differently if 'dst' is a symbolic link: they modified the
     permission bits of 'dst' itself rather than the file it points to
     if 'follow_symlinks' is true or 'src' is not a symbolic link, and
     did not modify the permission bits if 'follow_symlinks' is false
     and 'src' is a symbolic link.

   - gh-113119(44): *note os.posix_spawn(): 220. now accepts ‘env=None’,
     which makes the newly spawned process use the current process
     environment.  Patch by Jakub Kulik.

   - gh-113202(45): Add a ‘strict’ option to ‘batched()’ in the
     ‘itertools’ module.

   - gh-61648(46): Detect line numbers of properties in doctests.

   - gh-113175(47): Sync with importlib_metadata 7.0, including improved
     type annotations, fixed issue with symlinked packages in
     ‘package_distributions’, added ‘EntryPoints.__repr__’, introduced
     the ‘diagnose’ script, added ‘Distribution.origin’ property, and
     removed deprecated ‘EntryPoint’ access by numeric index (tuple
     behavior).

   - gh-59616(48): Add support of *note os.lchmod(): 21a. and the
     'follow_symlinks' argument in *note os.chmod(): 21b. on Windows.
     Note that the default value of 'follow_symlinks' in ‘os.lchmod()’
     is ‘False’ on Windows.

   - gh-112559(49): *note signal.signal(): 1178. and *note
     signal.getsignal(): 17bd. no longer call ‘repr’ on callable
     handlers.  *note asyncio.run(): 47f. and *note
     asyncio.Runner.run(): 17be. no longer call ‘repr’ on the task
     results.  Patch by Yilei Yang.

   - gh-112962(50): *note dis: 38. module functions add cache
     information to the *note Instruction: 1da. instance rather than
     creating fake ‘Instruction’ instances to represent the cache
     entries.

   - gh-112989(51): Reduce overhead to connect sockets with *note
     asyncio: a. SelectorEventLoop.

   - gh-112970(52): Use ‘closefrom()’ on Linux where available (e.g.
     glibc-2.34), rather than only FreeBSD.

   - gh-110190(53): Fix ctypes structs with array on PPC64LE platform by
     setting ‘MAX_STRUCT_SIZE’ to 64 in stgdict.  Patch by Diego Russo.

   - gh-112540(54): The statistics.geometric_mean() function now returns
     zero for datasets containing a zero.  Formerly, it would raise an
     exception.

   - gh-87286(55): Added ‘LOG_FTP’, ‘LOG_NETINFO’, ‘LOG_REMOTEAUTH’,
     ‘LOG_INSTALL’, ‘LOG_RAS’, and ‘LOG_LAUNCHD’ tot the *note syslog:
     dc. module, all of them constants on used on macOS.

   - gh-112800(56): Fix *note asyncio: a. ‘SubprocessTransport.close()’
     not to throw ‘PermissionError’ when used with setuid executables.

   - gh-51944(57): Add the following constants to the *note termios: e1.
     module.  These values are present in macOS system headers:
     ‘ALTWERASE’, ‘B14400’, ‘B28800’, ‘B7200’, ‘B76800’, ‘CCAR_OFLOW’,
     ‘CCTS_OFLOW’, ‘CDSR_OFLOW’, ‘CDTR_IFLOW’, ‘CIGNORE’, ‘CRTS_IFLOW’,
     ‘EXTPROC’, ‘IUTF8’, ‘MDMBUF’, ‘NL2’, ‘NL3’, ‘NOKERNINFO’, ‘ONOEOT’,
     ‘OXTABS’, ‘VDSUSP’, ‘VSTATUS’.

   - gh-79325(58): Fix an infinite recursion error in *note
     tempfile.TemporaryDirectory(): 127a. cleanup on Windows.

   - gh-94692(59): *note shutil.rmtree(): 301. now only catches OSError
     exceptions.  Previously a symlink attack resistant version of
     ‘shutil.rmtree()’ could ignore or pass to the error handler
     arbitrary exception when invalid arguments were provided.

   - gh-112736(60): The use of del-safe symbols in ‘subprocess’ was
     refactored to allow for use in cross-platform build environments.

   - gh-112727(61): Speed up *note pathlib.Path.absolute(): 17bf.  Patch
     by Barney Gale.

   - gh-74690(62): Speedup *note issubclass(): 7c5. checks against
     simple *note runtime-checkable protocols: 446. by around 6%.  Patch
     by Alex Waygood.

   - gh-74690(63): Speedup *note isinstance(): 445. checks by roughly
     20% for *note runtime-checkable protocols: 446. that only have one
     callable member.  Speedup *note issubclass(): 7c5. checks for these
     protocols by roughly 10%.  Patch by Alex Waygood.

   - gh-112645(64): Remove deprecation error on passing ‘onerror’ to
     *note shutil.rmtree(): 301.

   - gh-112640(65): Add ‘kwdefaults’ parameter to *note
     types.FunctionType: 88a. to set default keyword argument values.

   - gh-112622(66): Ensure ‘name’ parameter is passed to event loop in
     *note asyncio.create_task(): 1bf.

   - gh-112618(67): Fix a caching bug relating to *note
     typing.Annotated: 947.  ‘Annotated[str, True]’ is no longer
     identical to ‘Annotated[str, 1]’.

   - gh-112334(68): Fixed a performance regression in 3.12’s *note
     subprocess: d6. on Linux where it would no longer use the fast-path
     ‘vfork()’ system call when it could have due to a logic bug,
     instead falling back to the safe but slower ‘fork()’.

     Also fixed a second 3.12.0 potential security bug.  If a value of
     ‘extra_groups=[]’ was passed to *note subprocess.Popen: 199. or
     related APIs, the underlying ‘setgroups(0, NULL)’ system call to
     clear the groups list would not be made in the child process prior
     to ‘exec()’.

     This was identified via code inspection in the process of fixing
     the first bug.

   - gh-110190(69): Fix ctypes structs with array on Arm platform by
     setting ‘MAX_STRUCT_SIZE’ to 32 in stgdict.  Patch by Diego Russo.

   - gh-81194(70): Fix a crash in *note socket.if_indextoname(): a3c.
     with specific value (UINT_MAX). Fix an integer overflow in
     ‘socket.if_indextoname()’ on 64-bit non-Windows platforms.

   - gh-112578(71): Fix a spurious *note RuntimeWarning: 1bd. when
     executing the *note zipfile: 131. module.

   - gh-112516(72): Update the bundled copy of pip to version 23.3.1.

   - gh-112510(73): Add *note readline.backend: 17c0. for the backend
     readline uses (‘editline’ or ‘readline’)

   - gh-112328(74): [Enum] Make ‘EnumDict’, ‘EnumDict.member_names’,
     ‘EnumType._add_alias_’ and ‘EnumType._add_value_alias_’ public.

   - gh-112509(75): Fix edge cases that could cause a key to be present
     in both the ‘__required_keys__’ and ‘__optional_keys__’ attributes
     of a *note typing.TypedDict: 162.  Patch by Jelle Zijlstra.

   - gh-101336(76): Add ‘keep_alive’ keyword parameter for
     ‘AbstractEventLoop.create_server()’ and
     ‘BaseEventLoop.create_server()’.

   - gh-63284(77): Added support for TLS-PSK (pre-shared key) mode to
     the *note ssl: d0. module.

   - gh-112414(78): Fix regression in Python 3.12 where calling *note
     repr(): 803. on a module that had been imported using a custom
     *note loader: 17c1. could fail with *note AttributeError: 34e.
     Patch by Alex Waygood.

   - gh-112358(79): Revert change to *note struct.Struct: 15ad.
     initialization that broke some cases of subclassing.

   - gh-112405(80): Optimize *note pathlib.PurePath.relative_to(): 2ca.
     Patch by Alex Waygood.

   - gh-94722(81): Fix bug where comparison between instances of *note
     DocTest: 17c2. fails if one of them has ‘None’ as its lineno.

   - gh-112361(82): Speed up a small handful of *note pathlib: a4.
     methods by removing some temporary objects.

   - gh-112345(83): Improve error message when trying to call *note
     issubclass(): 7c5. against a *note typing.Protocol: 264. that has
     non-method members.  Patch by Randolf Scholz.

   - gh-112137(84): Change *note dis: 38. output to display no-lineno as
     “–” instead of “None”.

   - gh-112332(85): Deprecate the ‘exc_type’ field of *note
     traceback.TracebackException: 25c.  Add ‘exc_type_str’ to replace
     it.

   - gh-81620(86): Add extra tests for *note random.binomialvariate():
     4b3.

   - gh-112292(87): Fix a crash in *note readline: ba. when imported
     from a sub interpreter.  Patch by Anthony Shaw

   - gh-77621(88): Slightly improve the import time of the *note
     pathlib: a4. module by deferring some imports.  Patch by Barney
     Gale.

   - gh-112137(89): Change *note dis: 38. output to display logical
     labels for jump targets instead of offsets.

   - gh-112139(90): Add ‘Signature.format()’ to format signatures to
     string with extra options.  And use it in *note pydoc: b5. to
     render more readable signatures that have new lines between
     parameters.

   - gh-112105(91): Make *note readline.set_completer_delims(): 17c3.
     work with libedit

   - gh-106922(92): Display multiple lines with ‘traceback’ when errors
     span multiple lines.

   - gh-111874(93): When creating a *note typing.NamedTuple: 2b0. class,
     ensure *note __set_name__(): c6f. is called on all objects that
     define ‘__set_name__’ and exist in the values of the ‘NamedTuple’
     class’s class dictionary.  Patch by Alex Waygood.

   - gh-68166(94): Add support of the “vsapi” element type in *note
     tkinter.ttk.Style.element_create(): 258.

   - gh-110275(95): Named tuple’s methods ‘_replace()’ and
     ‘__replace__()’ now raise TypeError instead of ValueError for
     invalid keyword arguments.

   - gh-99367(96): Do not mangle ‘sys.path[0]’ in *note pdb: a5. if
     safe_path is set

   - gh-111615(97): Fix a regression caused by a fix to gh-93162(98)
     whereby you couldn’t configure a ‘QueueHandler’ without specifying
     handlers.

   - gh-75666(99): Fix the behavior of *note tkinter: f0. widget’s
     ‘unbind()’ method with two arguments.  Previously,
     ‘widget.unbind(sequence, funcid)’ destroyed the current binding for
     'sequence', leaving 'sequence' unbound, and deleted the 'funcid'
     command.  Now it removes only 'funcid' from the binding for
     'sequence', keeping other commands, and deletes the 'funcid'
     command.  It leaves 'sequence' unbound only if 'funcid' was the
     last bound command.

   - gh-67790(100): Implement basic formatting support (minimum width,
     alignment, fill) for *note fractions.Fraction: 1e7.

   - gh-111049(101): Fix crash during garbage collection of the *note
     io.BytesIO: ed8. buffer object.

   - gh-102980(102): Redirect the output of ‘interact’ command of *note
     pdb: a5. to the same channel as the debugger.  Add tests and
     improve docs.

   - gh-102988(103): *note email.utils.getaddresses(): 1e1. and *note
     email.utils.parseaddr(): 1e2. now return ‘('', '')’ 2-tuples in
     more situations where invalid email addresses are encountered
     instead of potentially inaccurate values.  Add optional 'strict'
     parameter to these two functions: use ‘strict=False’ to get the old
     behavior, accept malformed inputs.  ‘getattr(email.utils,
     'supports_strict_parsing', False)’ can be use to check if the
     'strict' parameter is available.  Patch by Thomas Dwyer and Victor
     Stinner to improve the CVE 2023-27043(104) fix.

   - gh-52161(105): *note cmd.Cmd.do_help(): 17c4. now cleans docstrings
     with *note inspect.cleandoc(): 17c5. before writing them.  Patch by
     Filip Łapkiewicz.

   - gh-82300(106): Add ‘track’ parameter to *note
     multiprocessing.shared_memory.SharedMemory: 176c. that allows using
     shared memory blocks without having to register with the POSIX
     resource tracker that automatically releases them upon process
     exit.

   - gh-110109(107): Add private ‘pathlib._PurePathBase’ class: a base
     class for *note pathlib.PurePath: 4a9. that omits certain magic
     methods.  It may be made public (along with ‘_PathBase’) in future.

   - gh-109858(108): Protect *note zipfile: 131. from “quoted-overlap”
     zipbomb.  It now raises BadZipFile when try to read an entry that
     overlaps with other entry or central directory.

   - gh-109786(109): Fix possible reference leaks and crash when
     re-enter the ‘__next__()’ method of *note itertools.pairwise: 81b.

   - gh-91539(110): Small (10 - 20%) and trivial performance improvement
     of ‘urllib.request.getproxies_environment()’, typically useful when
     there are many environment variables to go over.

   - gh-103363(111): Add 'follow_symlinks' keyword-only argument to
     *note pathlib.Path.owner(): 231. and *note group(): 232, defaulting
     to ‘True’.

   - gh-102130(112): Support tab completion in *note cmd: 19. for
     ‘editline’.

   - gh-99437(113): *note runpy.run_path(): 181. now decodes path-like
     objects, making sure __file__ and sys.argv[0] of the module being
     run are always strings.

   - gh-104003(114): Add *note warnings.deprecated(): 160, a decorator
     to mark deprecated functions to static type checkers and to warn on
     usage of deprecated classes and functions.  See PEP 702(115).
     Patch by Jelle Zijlstra.

   - gh-103708(116): Make hardcoded python name, a configurable
     parameter so that different implementations of python can override
     it instead of making huge diffs in sysconfig.py

   - gh-66515(117): *note mailbox.MH: 17c6. now supports folders that do
     not contain a ‘.mh_sequences’ file (e.g.  Claws Mail IMAP-cache
     folders).  Patch by Serhiy Storchaka.

   - gh-83162(118): Renamed ‘re.error’ to ‘PatternError’ for clarity,
     and kept ‘re.error’ for backward compatibility.  Patch by Matthias
     Bussonnier and Adam Chhina.

   - gh-91133(119): Fix a bug in *note tempfile.TemporaryDirectory:
     127a. cleanup, which now no longer dereferences symlinks when
     working around file system permission errors.

   - bpo-43153(120): On Windows, ‘tempfile.TemporaryDirectory’
     previously masked a ‘PermissionError’ with ‘NotADirectoryError’
     during directory cleanup.  It now correctly raises
     ‘PermissionError’ if errors are not ignored.  Patch by Andrei
     Kulakov and Ken Jin.

   - bpo-32731(121): *note getpass.getuser(): 41b. now raises *note
     OSError: 41a. for all failures rather than *note ImportError: 41c.
     on systems lacking the *note pwd: b2. module or *note KeyError:
     345. if the password database is empty.

   - bpo-34321(122): *note mmap.mmap: 20b. now has a 'trackfd' parameter
     on Unix; if it is ‘False’, the file descriptor specified by
     'fileno' will not be duplicated.

   - bpo-35332(123): The *note shutil.rmtree(): 301. function now
     ignores errors when calling *note os.close(): b90. when
     'ignore_errors' is ‘True’, and ‘os.close()’ no longer retried after
     error.

   - bpo-35928(124): *note io.TextIOWrapper: 7bf. now correctly handles
     the decoding buffer after ‘read()’ and ‘write()’.

   - bpo-26791(125): *note shutil.move(): a6a. now moves a symlink into
     a directory when that directory is the target of the symlink.  This
     provides the same behavior as the mv shell command.  The previous
     behavior raised an exception.  Patch by Jeffrey Kintscher.

   - bpo-41422(126): Fixed memory leaks of *note pickle.Pickler: a2b.
     and *note pickle.Unpickler: 15c4. involving cyclic references via
     the internal memo mapping.

   - bpo-19821(127): The ‘pydoc.ispackage()’ function has been
     deprecated.

   - bpo-40262(128): The ‘ssl.SSLSocket.recv_into()’ method no longer
     requires the 'buffer' argument to implement ‘__len__’ and supports
     buffers with arbitrary item size.

   - bpo-39912(129): *note warnings.filterwarnings(): 14f8. and *note
     warnings.simplefilter(): 6c4. now raise appropriate exceptions
     instead of ‘AssertionError’.  Patch contributed by Rémi Lapeyre.

   - bpo-37260(130): Fixed a race condition in *note shutil.rmtree():
     301. in which directory entries removed by another process or
     thread while ‘shutil.rmtree()’ is running can cause it to raise
     FileNotFoundError.  Patch by Jeffrey Kintscher.

   - bpo-36959(131): Fix some error messages for invalid ISO format
     string combinations in ‘strptime()’ that referred to directives not
     contained in the format string.  Patch by Gordon P. Hemsley.

   - bpo-18060(132): Fixed a class inheritance issue that can cause
     segfaults when deriving two or more levels of subclasses from a
     base class of Structure or Union.

   - bpo-29779(133): Add a new *note PYTHON_HISTORY: 191. environment
     variable to set the location of a ‘.python_history’ file.

   - bpo-21360(134): *note mailbox.Maildir: 41f. now ignores files with
     a leading dot.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114077

   (2) https://github.com/python/cpython/issues/111803

   (3) https://github.com/python/cpython/issues/114014

   (4) https://github.com/python/cpython/issues/108364

   (5) https://github.com/python/cpython/issues/113971

   (6) https://github.com/python/cpython/issues/113877

   (7) https://github.com/python/cpython/issues/113868

   (8) https://github.com/python/cpython/issues/113848

   (9) https://github.com/python/cpython/issues/113661

   (10) https://github.com/python/cpython/issues/96037

   (11) https://github.com/python/cpython/issues/113781

   (12) https://github.com/python/cpython/issues/113238

   (13) https://github.com/python/cpython/issues/111693

   (14) https://github.com/python/cpython/issues/113791

   (15) https://github.com/python/cpython/issues/112932

   (16) https://github.com/python/cpython/issues/113568

   (17) https://github.com/python/cpython/issues/113594

   (18) https://github.com/python/cpython/issues/113538

   (19) https://github.com/python/cpython/issues/113626

   (20) https://github.com/python/cpython/issues/85567

   (21) https://github.com/python/cpython/issues/113537

   (22) https://github.com/python/cpython/issues/89850

   (23) https://github.com/python/cpython/issues/113569

   (24) https://github.com/python/cpython/issues/101225

   (25) https://github.com/python/cpython/issues/113568

   (26) https://github.com/python/cpython/issues/113543

   (27) https://github.com/python/cpython/issues/113028

   (28) https://github.com/python/cpython/issues/113421

   (29) https://github.com/python/cpython/issues/111784

   (30) https://github.com/python/cpython/issues/113407

   (31) https://github.com/python/cpython/issues/113320

   (32) https://github.com/python/cpython/issues/53502

   (33) https://github.com/python/cpython/issues/113358

   (34) https://github.com/python/cpython/issues/113214

   (35) https://github.com/python/cpython/issues/113246

   (36) https://github.com/python/cpython/issues/87264

   (37) https://github.com/python/cpython/issues/112182

   (38) https://github.com/python/cpython/issues/113225

   (39) https://github.com/python/cpython/issues/113149

   (40) https://github.com/python/cpython/issues/113117

   (41) https://github.com/python/cpython/issues/113199

   (42) https://github.com/python/cpython/issues/113191

   (43) https://github.com/python/cpython/issues/113188

   (44) https://github.com/python/cpython/issues/113119

   (45) https://github.com/python/cpython/issues/113202

   (46) https://github.com/python/cpython/issues/61648

   (47) https://github.com/python/cpython/issues/113175

   (48) https://github.com/python/cpython/issues/59616

   (49) https://github.com/python/cpython/issues/112559

   (50) https://github.com/python/cpython/issues/112962

   (51) https://github.com/python/cpython/issues/112989

   (52) https://github.com/python/cpython/issues/112970

   (53) https://github.com/python/cpython/issues/110190

   (54) https://github.com/python/cpython/issues/112540

   (55) https://github.com/python/cpython/issues/87286

   (56) https://github.com/python/cpython/issues/112800

   (57) https://github.com/python/cpython/issues/51944

   (58) https://github.com/python/cpython/issues/79325

   (59) https://github.com/python/cpython/issues/94692

   (60) https://github.com/python/cpython/issues/112736

   (61) https://github.com/python/cpython/issues/112727

   (62) https://github.com/python/cpython/issues/74690

   (63) https://github.com/python/cpython/issues/74690

   (64) https://github.com/python/cpython/issues/112645

   (65) https://github.com/python/cpython/issues/112640

   (66) https://github.com/python/cpython/issues/112622

   (67) https://github.com/python/cpython/issues/112618

   (68) https://github.com/python/cpython/issues/112334

   (69) https://github.com/python/cpython/issues/110190

   (70) https://github.com/python/cpython/issues/81194

   (71) https://github.com/python/cpython/issues/112578

   (72) https://github.com/python/cpython/issues/112516

   (73) https://github.com/python/cpython/issues/112510

   (74) https://github.com/python/cpython/issues/112328

   (75) https://github.com/python/cpython/issues/112509

   (76) https://github.com/python/cpython/issues/101336

   (77) https://github.com/python/cpython/issues/63284

   (78) https://github.com/python/cpython/issues/112414

   (79) https://github.com/python/cpython/issues/112358

   (80) https://github.com/python/cpython/issues/112405

   (81) https://github.com/python/cpython/issues/94722

   (82) https://github.com/python/cpython/issues/112361

   (83) https://github.com/python/cpython/issues/112345

   (84) https://github.com/python/cpython/issues/112137

   (85) https://github.com/python/cpython/issues/112332

   (86) https://github.com/python/cpython/issues/81620

   (87) https://github.com/python/cpython/issues/112292

   (88) https://github.com/python/cpython/issues/77621

   (89) https://github.com/python/cpython/issues/112137

   (90) https://github.com/python/cpython/issues/112139

   (91) https://github.com/python/cpython/issues/112105

   (92) https://github.com/python/cpython/issues/106922

   (93) https://github.com/python/cpython/issues/111874

   (94) https://github.com/python/cpython/issues/68166

   (95) https://github.com/python/cpython/issues/110275

   (96) https://github.com/python/cpython/issues/99367

   (97) https://github.com/python/cpython/issues/111615

   (98) https://github.com/python/cpython/issues/93162

   (99) https://github.com/python/cpython/issues/75666

   (100) https://github.com/python/cpython/issues/67790

   (101) https://github.com/python/cpython/issues/111049

   (102) https://github.com/python/cpython/issues/102980

   (103) https://github.com/python/cpython/issues/102988

   (104) https://www.cve.org/CVERecord?id=CVE-2023-27043

   (105) https://github.com/python/cpython/issues/52161

   (106) https://github.com/python/cpython/issues/82300

   (107) https://github.com/python/cpython/issues/110109

   (108) https://github.com/python/cpython/issues/109858

   (109) https://github.com/python/cpython/issues/109786

   (110) https://github.com/python/cpython/issues/91539

   (111) https://github.com/python/cpython/issues/103363

   (112) https://github.com/python/cpython/issues/102130

   (113) https://github.com/python/cpython/issues/99437

   (114) https://github.com/python/cpython/issues/104003

   (115) https://peps.python.org/pep-0702/

   (116) https://github.com/python/cpython/issues/103708

   (117) https://github.com/python/cpython/issues/66515

   (118) https://github.com/python/cpython/issues/83162

   (119) https://github.com/python/cpython/issues/91133

   (120) https://bugs.python.org/issue?@action=redirect&bpo=43153

   (121) https://bugs.python.org/issue?@action=redirect&bpo=32731

   (122) https://bugs.python.org/issue?@action=redirect&bpo=34321

   (123) https://bugs.python.org/issue?@action=redirect&bpo=35332

   (124) https://bugs.python.org/issue?@action=redirect&bpo=35928

   (125) https://bugs.python.org/issue?@action=redirect&bpo=26791

   (126) https://bugs.python.org/issue?@action=redirect&bpo=41422

   (127) https://bugs.python.org/issue?@action=redirect&bpo=19821

   (128) https://bugs.python.org/issue?@action=redirect&bpo=40262

   (129) https://bugs.python.org/issue?@action=redirect&bpo=39912

   (130) https://bugs.python.org/issue?@action=redirect&bpo=37260

   (131) https://bugs.python.org/issue?@action=redirect&bpo=36959

   (132) https://bugs.python.org/issue?@action=redirect&bpo=18060

   (133) https://bugs.python.org/issue?@action=redirect&bpo=29779

   (134) https://bugs.python.org/issue?@action=redirect&bpo=21360


File: python.info,  Node: Documentation<17>,  Next: Tests<19>,  Prev: Library<37>,  Up: Python 3 13 0 alpha 3

1.23.25.4 Documentation
.......................

   - gh-111699(1): Relocate ‘smtpd’ deprecation notice to its own
     section rather than under ‘locale’ in What’s New in Python 3.12
     document

   - gh-110746(2): Improved markup for valid options/values for methods
     ttk.treeview.column and ttk.treeview.heading, and for Layouts.

   - gh-95649(3): Document that the *note asyncio: a. module contains
     code taken from v0.16.0 of the uvloop project(4), as well as the
     required MIT licensing information.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111699

   (2) https://github.com/python/cpython/issues/110746

   (3) https://github.com/python/cpython/issues/95649

   (4) https://github.com/MagicStack/uvloop/tree/v0.16.0


File: python.info,  Node: Tests<19>,  Next: Build<19>,  Prev: Documentation<17>,  Up: Python 3 13 0 alpha 3

1.23.25.5 Tests
...............

   - gh-111798(1): Disable ‘test_super_deep()’ from ‘test_call’ under
     pydebug builds on WASI; the stack depth is too small to make the
     test useful.

   - gh-111801(2): Lower the recursion limit in ‘test_isinstance’ for
     ‘test_infinitely_many_bases()’.  This prevents a stack overflow on
     a pydebug build of WASI.

   - gh-111802(3): Specify a low recursion depth for
     ‘test_bad_getattr()’ in ‘test.pickletester’ to avoid exhausting the
     stack under a pydebug build for WASI.

   - gh-44626(4): Fix *note os.path.isabs(): 224. incorrectly returning
     ‘True’ when given a path that starts with exactly one (back)slash
     on Windows.

     Fix ‘pathlib.PureWindowsPath.is_absolute()’ incorrectly returning
     ‘False’ for some paths beginning with two (back)slashes.

   - gh-113633(5): Use module state for the _testcapi extension module.

   - gh-109980(6): Fix ‘test_tarfile_vs_tar’ in ‘test_shutil’ for macOS,
     where system tar can include more information in the archive than
     *note shutil.make_archive: 4b6.

   - gh-112769(7): The tests now correctly compare zlib version when
     *note zlib.ZLIB_RUNTIME_VERSION: 11b2. contains non-integer
     suffixes.  For example zlib-ng defines the version as
     ‘1.3.0.zlib-ng’.

   - gh-112334(8): Adds a regression test to verify that ‘vfork()’ is
     used when expected by *note subprocess: d6. on vfork enabled POSIX
     systems (Linux).

   - gh-108927(9): Fixed order dependence in running tests in the same
     process when a test that has submodules (e.g.  test_importlib)
     follows a test that imports its submodule (e.g.
     test_importlib.util) and precedes a test (e.g.  test_unittest or
     test_compileall) that uses that submodule.

   - bpo-40648(10): Test modes that file can get with chmod() on
     Windows.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111798

   (2) https://github.com/python/cpython/issues/111801

   (3) https://github.com/python/cpython/issues/111802

   (4) https://github.com/python/cpython/issues/44626

   (5) https://github.com/python/cpython/issues/113633

   (6) https://github.com/python/cpython/issues/109980

   (7) https://github.com/python/cpython/issues/112769

   (8) https://github.com/python/cpython/issues/112334

   (9) https://github.com/python/cpython/issues/108927

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40648


File: python.info,  Node: Build<19>,  Next: Windows<17>,  Prev: Tests<19>,  Up: Python 3 13 0 alpha 3

1.23.25.6 Build
...............

   - gh-114013(1): Fix ‘Tools/wasm/wasi.py’ to not include the path to
     ‘python.wasm’ as part of ‘HOSTRUNNER’.  The environment variable is
     meant to specify how to run the WASI host only, having
     ‘python.wasm’ and relevant flags appended to the ‘HOSTRUNNER’.
     This fixes ‘make test’ work.

   - gh-113258(2): Changed the Windows build to write out generated
     frozen modules into the build tree instead of the source tree.

   - gh-112305(3): Fixed the ‘check-clean-src’ step performed on out of
     tree builds to detect errant ‘$(srcdir)/Python/frozen_modules/*.h’
     files and recommend appropriate source tree cleanup steps to get a
     working build again.

   - gh-112536(4): Add support for thread sanitizer (TSAN)

   - gh-112867(5): Fix the build for the case that
     WITH_PYMALLOC_RADIX_TREE=0 set.

   - gh-103065(6): Introduce ‘Tools/wasm/wasi.py’ to simplify doing a
     WASI build.

   - bpo-11102(7): The *note os.major(): 1722, *note os.makedev(): 1724,
     and *note os.minor(): 1723. functions are now available on HP-UX
     v3.

   - bpo-36351(8): Do not set ipv6type when cross-compiling.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114013

   (2) https://github.com/python/cpython/issues/113258

   (3) https://github.com/python/cpython/issues/112305

   (4) https://github.com/python/cpython/issues/112536

   (5) https://github.com/python/cpython/issues/112867

   (6) https://github.com/python/cpython/issues/103065

   (7) https://bugs.python.org/issue?@action=redirect&bpo=11102

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36351


File: python.info,  Node: Windows<17>,  Next: macOS<12>,  Prev: Build<19>,  Up: Python 3 13 0 alpha 3

1.23.25.7 Windows
.................

   - gh-114096(1): Process privileges that are activated for creating
     directory junctions are now restored afterwards, avoiding behaviour
     changes in other parts of the program.

   - gh-111877(2): *note os.stat(): 4a3. calls were returning incorrect
     time values for files that could not be accessed directly.

   - gh-111973(3): Update Windows installer to use SQLite 3.44.2.

   - gh-113009(4): *note multiprocessing: 94.: On Windows, fix a race
     condition in ‘Process.terminate()’: no longer set the ‘returncode’
     attribute to always call ‘WaitForSingleObject()’ in
     ‘Process.wait()’.  Previously, sometimes the process was still
     running after ‘TerminateProcess()’ even if ‘GetExitCodeProcess()’
     is not ‘STILL_ACTIVE’.  Patch by Victor Stinner.

   - gh-86179(5): Fixes path calculations when launching Python on
     Windows through a symlink.

   - gh-71383(6): Update Tcl/Tk in Windows installer to 8.6.13 with a
     patch to suppress incorrect ThemeChanged warnings.

   - gh-111650(7): Ensures the ‘Py_GIL_DISABLED’ preprocessor variable
     is defined in ‘pyconfig.h’ so that extension modules written in C
     are able to use it.

   - gh-112278(8): Reduce the time cost for some functions in *note
     platform: aa. on Windows if current user has no permission to the
     WMI.

   - gh-73427(9): Deprecate *note sys._enablelegacywindowsfsencoding():
     2ae.  Use *note PYTHONLEGACYWINDOWSFSENCODING: 2af. instead.  Patch
     by Inada Naoki.

   - gh-87868(10): Correctly sort and remove duplicate environment
     variables in ‘_winapi.CreateProcess()’.

   - bpo-37308(11): Fix mojibake in *note mmap.mmap: 20b. when using a
     non-ASCII 'tagname' argument on Windows.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/114096

   (2) https://github.com/python/cpython/issues/111877

   (3) https://github.com/python/cpython/issues/111973

   (4) https://github.com/python/cpython/issues/113009

   (5) https://github.com/python/cpython/issues/86179

   (6) https://github.com/python/cpython/issues/71383

   (7) https://github.com/python/cpython/issues/111650

   (8) https://github.com/python/cpython/issues/112278

   (9) https://github.com/python/cpython/issues/73427

   (10) https://github.com/python/cpython/issues/87868

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37308


File: python.info,  Node: macOS<12>,  Next: IDLE<15>,  Prev: Windows<17>,  Up: Python 3 13 0 alpha 3

1.23.25.8 macOS
...............

   - gh-113666(1): Add the following constants to module *note stat:
     d1.: ‘UF_SETTABLE’, ‘UF_TRACKED’, ‘UF_DATAVAULT’, ‘SF_SUPPORTED’,
     ‘SF_SETTABLE’, ‘SF_SYNTHETIC’, ‘SF_RESTRICTED’, ‘SF_FIRMLINK’ and
     ‘SF_DATALESS’.  The values ‘UF_SETTABLE’, ‘SF_SUPPORTED’,
     ‘SF_SETTABLE’ and ‘SF_SYNTHETIC’ are only available on macOS.

   - gh-113536(2): *note os.waitid(): dc7. is now available on macOS

   - gh-110459(3): Running ‘configure ... --with-openssl-rpath=X/Y/Z’ no
     longer fails to detect OpenSSL on macOS.

   - gh-74573(4): Document that *note dbm.ndbm: 34. can silently corrupt
     DBM files on updates when exceeding undocumented platform limits,
     and can crash (segmentation fault) when reading such a corrupted
     file.  (FB8919203)

   - gh-65701(5): The ‘freeze’ tool doesn’t work with framework builds
     of Python.  Document this and bail out early when running the tool
     with such a build.

   - gh-87277(6): webbrowser: Don’t look for X11 browsers on macOS.
     Those are generally not used and probing for them can result in
     starting XQuartz even if it isn’t used otherwise.

   - gh-111973(7): Update macOS installer to use SQLite 3.44.2.

   - gh-108269(8): Set ‘CFBundleAllowMixedLocalizations’ to true in the
     Info.plist for the framework, embedded Python.app and IDLE.app with
     framework installs on macOS. This allows applications to pick up
     the user’s preferred locale when that’s different from english.

   - gh-102362(9): Make sure the result of ‘sysconfig.get_plaform()’
     includes at least a major and minor versions, even if
     ‘MACOSX_DEPLOYMENT_TARGET’ is set to only a major version during
     build to match the format expected by pip.

   - gh-110017(10): Disable a signal handling stress test on macOS due
     to a bug in macOS (FB13453490).

   - gh-110820(11): Make sure the preprocessor definitions for
     ‘ALIGNOF_MAX_ALIGN_T’, ‘SIZEOF_LONG_DOUBLE’ and
     ‘HAVE_GCC_ASM_FOR_X64’ are correct for Universal 2 builds on macOS.

   - gh-109981(12): Use ‘/dev/fd’ on macOS to determine the number of
     open files in ‘test.support.os_helper.fd_count’ to avoid a crash
     with “guarded” file descriptors when probing for open files.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/113666

   (2) https://github.com/python/cpython/issues/113536

   (3) https://github.com/python/cpython/issues/110459

   (4) https://github.com/python/cpython/issues/74573

   (5) https://github.com/python/cpython/issues/65701

   (6) https://github.com/python/cpython/issues/87277

   (7) https://github.com/python/cpython/issues/111973

   (8) https://github.com/python/cpython/issues/108269

   (9) https://github.com/python/cpython/issues/102362

   (10) https://github.com/python/cpython/issues/110017

   (11) https://github.com/python/cpython/issues/110820

   (12) https://github.com/python/cpython/issues/109981


File: python.info,  Node: IDLE<15>,  Next: C API<19>,  Prev: macOS<12>,  Up: Python 3 13 0 alpha 3

1.23.25.9 IDLE
..............

   - gh-72284(1): Improve the lists of features, editor key bindings,
     and shell key bingings in the IDLE doc.

   - gh-113903(2): Fix rare failure of test.test_idle, in
     test_configdialog.

   - gh-113729(3): Fix the “Help -> IDLE Doc” menu bug in 3.11.7 and
     3.12.1.

   - gh-113269(4): Fix test_editor hang on macOS Catalina.

   - gh-112898(5): Fix processing unsaved files when quitting IDLE on
     macOS.

   - bpo-13586(6): Enter the selected text when opening the “Replace”
     dialog.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/72284

   (2) https://github.com/python/cpython/issues/113903

   (3) https://github.com/python/cpython/issues/113729

   (4) https://github.com/python/cpython/issues/113269

   (5) https://github.com/python/cpython/issues/112898

   (6) https://bugs.python.org/issue?@action=redirect&bpo=13586


File: python.info,  Node: C API<19>,  Prev: IDLE<15>,  Up: Python 3 13 0 alpha 3

1.23.25.10 C API
................

   - gh-106560(1): Fix redundant declarations in the public C API.
     Declare PyBool_Type, PyLong_Type and PySys_Audit() only once.
     Patch by Victor Stinner.

   - gh-112438(2): Fix support of format units “es”, “et”, “es#”, and
     “et#” in nested tuples in *note PyArg_ParseTuple(): 574.-like
     functions.

   - gh-111545(3): Add *note Py_HashPointer(): 36b. function to hash a
     pointer.  Patch by Victor Stinner.

   - gh-65210(4): Change the declaration of the 'keywords' parameter of
     *note PyArg_ParseTupleAndKeywords(): 386. and *note
     PyArg_VaParseTupleAndKeywords(): 387. for better compatibility with
     C++.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/106560

   (2) https://github.com/python/cpython/issues/112438

   (3) https://github.com/python/cpython/issues/111545

   (4) https://github.com/python/cpython/issues/65210


File: python.info,  Node: Python 3 13 0 alpha 2,  Next: Python 3 13 0 alpha 1,  Prev: Python 3 13 0 alpha 3,  Up: Changelog

1.23.26 Python 3.13.0 alpha 2
-----------------------------

'Release date: 2023-11-22'

* Menu:

* Core and Builtins: Core and Builtins<34>.
* Library: Library<38>.
* Tests: Tests<20>.
* Build: Build<20>.
* Windows: Windows<18>.
* macOS: macOS<13>.
* IDLE: IDLE<16>.
* Tools/Demos: Tools/Demos<11>.
* C API: C API<20>.


File: python.info,  Node: Core and Builtins<34>,  Next: Library<38>,  Up: Python 3 13 0 alpha 2

1.23.26.1 Core and Builtins
...........................

   - gh-112243(1): Don’t include comments in f-string debug expressions.
     Patch by Pablo Galindo

   - gh-112287(2): Slightly optimize the Tier 2 (uop) interpreter by
     only loading ‘oparg’ and ‘operand’ when needed.  Also double the
     trace size limit again, to 512 this time.

   - gh-112266(3): Change docstrings of *note __dict__: 55e. and
     ‘__weakref__’.

   - gh-111807(4): Lower the max parser stack depth to 1000 under WASI
     debug builds.

   - gh-111798(5): When Python is built in debug mode, set the C
     recursion limit to 500 instead of 1500.  A debug build is likely
     built with low optimization level which implies higher stack memory
     usage than a release build.  Patch by Victor Stinner.

   - gh-106529(6): Enable translating unspecialized ‘FOR_ITER’ to Tier
     2.

   - gh-111916(7): Make hashlib related modules thread-safe without the
     GIL

   - gh-81137(8): Deprecate assignment to a function’s ‘__code__’ field
     when the new code object is of a mismatched type (e.g., from a
     generator to a plain function).

   - gh-79932(9): Raise exception if *note frame.clear(): 280. is called
     on a suspended frame.

   - gh-81925(10): Implement native thread ids for GNU KFreeBSD.

   - gh-111843(11): Use exponential backoff to reduce the number of
     failed tier 2 optimization attempts by over 99%.

   - gh-110829(12): Joining a thread now ensures the underlying OS
     thread has exited.  This is required for safer fork() in
     multi-threaded processes.

   - gh-109369(13): Make sure that tier 2 traces are de-optimized if the
     code is instrumented

   - gh-111772(14): Specialize slot loads and stores for _Py_T_OBJECT as
     well as Py_T_OBJECT_EX

   - gh-111666(15): Speed up *note BaseExceptionGroup.derive(): 17d0,
     *note BaseExceptionGroup.subgroup(): 17d1, and *note
     BaseExceptionGroup.split(): 168f. by changing how they parse passed
     arguments.

   - gh-111654(16): Fix runtime crash when some error happens in opcode
     ‘LOAD_FROM_DICT_OR_DEREF’.

   - gh-111623(17): Add support for sharing tuples between interpreters
     using the cross-interpreter API. Patch by Anthony Shaw.

   - gh-111354(18): The oparg of *note YIELD_VALUE: 314. is now ‘1’ if
     the instruction is part of a yield-from or await, and ‘0’
     otherwise.

     The SUSPENDED frame state is now split into ‘SUSPENDED’ and
     ‘SUSPENDED_YIELD_FROM’.  This simplifies the code in ‘_PyGen_yf’.

   - gh-111520(19): Merge the Tier 1 (bytecode) and Tier 2 (micro-ops)
     interpreters together, moving the Tier 2 interpreter loop and
     switch into ‘_PyEval_EvalFrameDefault()’ in ‘Python/ceval.c’.  The
     ‘Python/executor.c’ file is gone.  Also the ‘TIER_ONE’ and
     ‘TIER_TWO’ macros are now handled by the code generator.

     'Beware!'  This changes the environment variables to enable
     micro-ops and their debugging to ‘PYTHON_UOPS’ and
     ‘PYTHON_LLTRACE’.

   - gh-109181(20): Speed up ‘Traceback’ object creation by lazily
     compute the line number.  Patch by Pablo Galindo

   - gh-111420(21): Allow type comments in parenthesized ‘with’
     statements

   - gh-111438(22): Add support for sharing floats between interpreters
     using the cross-interpreter API. Patch by Anthony Shaw.

   - gh-111435(23): Add support for sharing of ‘True’ and ‘False’
     between interpreters using the cross-interpreter API. Patch by
     Anthony Shaw.

   - gh-102388(24): Fix a bug where ‘iso2022_jp_3’ and ‘iso2022_jp_2004’
     codecs read out of bounds

   - gh-111366(25): Fix an issue in the *note codeop: 1c. that was
     causing *note SyntaxError: 18d. exceptions raised in the presence
     of invalid syntax to not contain precise error messages.  Patch by
     Pablo Galindo

   - gh-111380(26): Fix a bug that was causing *note SyntaxWarning: 469.
     to appear twice when parsing if invalid syntax is encountered
     later.  Patch by Pablo galindo

   - gh-111374(27): Added a new environment variable *note
     PYTHON_FROZEN_MODULES: 18e.  It determines whether or not frozen
     modules are ignored by the import machinery, equivalent of the
     *note -X frozen_modules: 176. command-line option.

   - gh-111354(28): Remove ‘oparg’ from *note YIELD_VALUE: 314.  Change
     ‘oparg’ of *note RESUME: 315. to include information about the
     except-depth.  These changes make it possible to simplify the code
     in generator close.

   - gh-94438(29): Fix a regression that prevented jumping across ‘is
     None’ and ‘is not None’ when debugging.  Patch by Savannah
     Ostrowski.

   - gh-67224(30): Show source lines in tracebacks when using the ‘-c’
     option when running Python.  Patch by Pablo Galindo

   - gh-111123(31): Fix a bug where a *note global: 18a. declaration in
     an *note except: 18b. block is rejected when the global is used in
     the *note else: 18c. block.

   - gh-110938(32): Fix error messages for indented blocks with
     functions and classes with generic type parameters.  Patch by Pablo
     Galindo

   - gh-109214(33): Remove unnecessary instruction pointer updates
     before returning from frames.

   - gh-110912(34): Correctly display the traceback for *note
     MemoryError: 15ab. exceptions using the *note traceback: fe.
     module.  Patch by Pablo Galindo

   - gh-109894(35): Fixed crash due to improperly initialized static
     *note MemoryError: 15ab. in subinterpreter.

   - gh-110892(36): Return ‘NULL’ for ‘PyTrace_RETURN’ events caused by
     an exception

   - gh-110864(37): Fix argument parsing by
     ‘_PyArg_UnpackKeywordsWithVararg’ for functions defining
     pos-or-keyword, vararg, and kw-only parameters.

   - gh-109094(38): Replace ‘prev_instr’ on the interpreter frame by
     ‘instr_ptr’ which points to the beginning of the instruction that
     is currently executing (or will execute once the frame resumes).

   - gh-110805(39): Allow the repl to show source code and complete
     tracebacks.  Patch by Pablo Galindo

   - gh-110722(40): Add ‘PYTHON_PRESITE=package.module’ to import a
     module early in the interpreter lifecycle before ‘site.py’ is
     executed.  Python needs to be *note built in debug mode: 1f9. for
     this option to exist.

   - gh-110481(41): Implement biased reference counting in
     ‘--disable-gil’ builds.

   - gh-110543(42): Fix regression in Python 3.12 where
     ‘types.CodeType.replace()’ would produce a broken code object if
     called on a module or class code object that contains a
     comprehension.  Patch by Jelle Zijlstra.

   - gh-89519(43): Removed chained *note classmethod: 166. descriptors
     (introduced in bpo-19072(44)).  This can no longer be used to wrap
     other descriptors such as *note property: 194.  The core design of
     this feature was flawed and caused a number of downstream problems.
     To “pass-through” a ‘classmethod’, consider using the ‘__wrapped__’
     attribute that was added in Python 3.10.

   - gh-103615(45): Use local events for opcode tracing

   - bpo-46657(46): Add mimalloc memory allocator support.

   - gh-106718(47): When PyConfig.stdlib_dir is explicitly set, it’s now
     respected and won’t be overridden by PyConfig.home.

   - gh-106905(48): Fix incorrect SystemError about AST constructor
     recursion depth mismatch.

   - gh-100445(49): Improve error message for unterminated strings with
     escapes.

   - bpo-45759(50): Improved error messages for ‘elif’/‘else’ statements
     not matching any valid statements.  Patch by Jeremiah Vivian.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112243

   (2) https://github.com/python/cpython/issues/112287

   (3) https://github.com/python/cpython/issues/112266

   (4) https://github.com/python/cpython/issues/111807

   (5) https://github.com/python/cpython/issues/111798

   (6) https://github.com/python/cpython/issues/106529

   (7) https://github.com/python/cpython/issues/111916

   (8) https://github.com/python/cpython/issues/81137

   (9) https://github.com/python/cpython/issues/79932

   (10) https://github.com/python/cpython/issues/81925

   (11) https://github.com/python/cpython/issues/111843

   (12) https://github.com/python/cpython/issues/110829

   (13) https://github.com/python/cpython/issues/109369

   (14) https://github.com/python/cpython/issues/111772

   (15) https://github.com/python/cpython/issues/111666

   (16) https://github.com/python/cpython/issues/111654

   (17) https://github.com/python/cpython/issues/111623

   (18) https://github.com/python/cpython/issues/111354

   (19) https://github.com/python/cpython/issues/111520

   (20) https://github.com/python/cpython/issues/109181

   (21) https://github.com/python/cpython/issues/111420

   (22) https://github.com/python/cpython/issues/111438

   (23) https://github.com/python/cpython/issues/111435

   (24) https://github.com/python/cpython/issues/102388

   (25) https://github.com/python/cpython/issues/111366

   (26) https://github.com/python/cpython/issues/111380

   (27) https://github.com/python/cpython/issues/111374

   (28) https://github.com/python/cpython/issues/111354

   (29) https://github.com/python/cpython/issues/94438

   (30) https://github.com/python/cpython/issues/67224

   (31) https://github.com/python/cpython/issues/111123

   (32) https://github.com/python/cpython/issues/110938

   (33) https://github.com/python/cpython/issues/109214

   (34) https://github.com/python/cpython/issues/110912

   (35) https://github.com/python/cpython/issues/109894

   (36) https://github.com/python/cpython/issues/110892

   (37) https://github.com/python/cpython/issues/110864

   (38) https://github.com/python/cpython/issues/109094

   (39) https://github.com/python/cpython/issues/110805

   (40) https://github.com/python/cpython/issues/110722

   (41) https://github.com/python/cpython/issues/110481

   (42) https://github.com/python/cpython/issues/110543

   (43) https://github.com/python/cpython/issues/89519

   (44) https://bugs.python.org/issue?@action=redirect&bpo=19072

   (45) https://github.com/python/cpython/issues/103615

   (46) https://bugs.python.org/issue?@action=redirect&bpo=46657

   (47) https://github.com/python/cpython/issues/106718

   (48) https://github.com/python/cpython/issues/106905

   (49) https://github.com/python/cpython/issues/100445

   (50) https://bugs.python.org/issue?@action=redirect&bpo=45759


File: python.info,  Node: Library<38>,  Next: Tests<20>,  Prev: Core and Builtins<34>,  Up: Python 3 13 0 alpha 2

1.23.26.2 Library
.................

   - gh-111942(1): Fix SystemError in the TextIOWrapper constructor with
     non-encodable “errors” argument in non-debug mode.

   - gh-111995(2): Added the ‘NI_IDN’ constant to the *note socket: cc.
     module when present in C at build time for use with *note
     socket.getnameinfo(): 17d3.

   - gh-109538(3): Issue warning message instead of having *note
     RuntimeError: 195. be displayed when event loop has already been
     closed at ‘StreamWriter.__del__()’.

   - gh-111942(4): Fix crashes in *note io.TextIOWrapper.reconfigure():
     b64. when pass invalid arguments, e.g.  non-string encoding.

   - gh-111460(5): *note curses: 2b.: restore wide character support
     (including *note curses.unget_wch(): 10dc. and *note get_wch():
     10db.) on macOS, which was unavailable due to a regression in
     Python 3.12.

   - gh-103791(6): *note contextlib.suppress: f5d. now supports
     suppressing exceptions raised as part of a *note
     BaseExceptionGroup: 25f, in addition to the recent support for
     *note ExceptionGroup: 1b6.

   - gh-111835(7): The *note mmap.mmap: 20b. class now has an *note
     seekable(): 20c. method that can be used when a seekable file-like
     object is required.  The *note seek(): 20d. method now returns the
     new absolute position.  Patch by Donghee Na.

   - gh-111804(8): Remove posix.fallocate() under WASI as the underlying
     posix_fallocate() is not available in WASI preview2.

   - gh-111841(9): Fix truncating arguments on an embedded null
     character in *note os.putenv(): 925. and *note os.unsetenv(): 924.
     on Windows.

   - gh-111768(10): *note wsgiref.util.is_hop_by_hop(): 17d4. is now
     exposed correctly in ‘__all__’.

   - gh-80731(11): Avoid executing the default function in *note
     cmd.Cmd: 17d5. in an except block

   - gh-111541(12): Fix *note doctest: 3a. for *note SyntaxError: 18d.
     not-builtin subclasses.

   - gh-111719(13): Add extra argument validation for ‘alias’ command in
     *note pdb: a5.

   - gh-111482(14): *note time: ee.: Make *note time.clock_gettime():
     11a2. and *note time.clock_gettime_ns(): afa. functions up to 2x
     faster by faster calling convention.  Patch by Victor Stinner.

   - gh-110894(15): Call loop exception handler for exceptions in
     ‘client_connected_cb’ of *note asyncio.start_server(): b32. so that
     applications can handle it.  Patch by Kumar Aditya.

   - gh-111531(16): Fix reference leaks in ‘bind_class()’ and
     ‘bind_all()’ methods of *note tkinter: f0. widgets.

   - gh-111246(17): *note asyncio.loop.create_unix_server(): 1ae. will
     now automatically remove the Unix socket when the server is closed.

   - gh-111356(18): Added *note io.text_encoding(): 17d6, *note
     io.DEFAULT_BUFFER_SIZE: 17d7, and *note
     io.IncrementalNewlineDecoder: 17d8. to ‘io.__all__’.

   - gh-66425(19): Remove the code to set the REMOTE_HOST header from
     wsgiref module, as it is unreachable.  This header is used for
     performance reasons, which is not necessary in the wsgiref module.

   - gh-111429(20): Speed up *note pathlib.PurePath.relative_to(): 2ca.
     and *note is_relative_to(): 2c9.

   - gh-111342(21): Fixed typo in *note math.sumprod(): 49a.

   - gh-68166(22): Remove mention of not supported “vsapi” element type
     in *note tkinter.ttk.Style.element_create(): 258.  Add tests for
     ‘element_create()’ and other ‘ttk.Style’ methods.  Add examples for
     ‘element_create()’ in the documentation.

   - gh-111388(23): Add ‘show_group’ parameter to *note
     traceback.format_exception_only(): 854, which allows to format
     *note ExceptionGroup: 1b6. instances.

   - gh-79033(24): Another attempt at fixing *note
     asyncio.Server.wait_closed(): 17d9.  It now blocks until both
     conditions are true: the server is closed, 'and' there are no more
     active connections.  (This means that in some cases where in 3.12.0
     this function would 'incorrectly' have returned immediately, it
     will now block; in particular, when there are no active connections
     but the server hasn’t been closed yet.)

   - gh-111259(25): Optimize recursive wildcards in *note pathlib: a4.

   - gh-111295(26): Fix *note time: ee. not checking for errors when
     initializing.

   - gh-111253(27): Add error checking during ‘_socket’ module init.

   - gh-111251(28): Fix ‘_blake2’ not checking for errors when
     initializing.

   - gh-111233(29): Fix *note select: c1. not checking for errors when
     initializing.

   - gh-111230(30): Fix *note ssl: d0. not checking for errors when
     initializing.

   - gh-111174(31): Fix crash in *note io.BytesIO.getbuffer(): 1236.
     called repeatedly for empty BytesIO.

   - gh-111187(32): Postpone removal version for
     locale.getdefaultlocale() to Python 3.15.

   - gh-111159(33): Fix *note doctest: 3a. output comparison for
     exceptions with notes.

   - gh-110910(34): Fix invalid state handling in *note
     asyncio.TaskGroup: 1b5. and *note asyncio.Timeout: 17da.  They now
     raise proper RuntimeError if they are improperly used and are left
     in consistent state after this.

   - gh-111092(35): Make turtledemo run without default root enabled.

   - gh-110944(36): Support alias and convenience vars for *note pdb:
     a5. completion

   - gh-110745(37): Added 'newline' parameter to *note
     pathlib.Path.read_text(): e78.  Patch by Junya Okabe.

   - gh-84583(38): Make *note pdb: a5. enter post-mortem mode even for
     *note SyntaxError: 18d.

   - gh-80675(39): Set ‘f_trace_lines = True’ on all frames upon *note
     pdb.set_trace(): 235.

   - gh-110771(40): Expose the setup and cleanup portions of
     ‘asyncio.run_forever()’ as the standalone methods
     ‘asyncio.run_forever_setup()’ and ‘asyncio.run_forever_cleanup()’.
     This allows for tighter integration with GUI event loops.

   - gh-110774(41): Support setting the *note asyncio.Runner: 603.
     loop_factory kwarg in *note unittest.IsolatedAsyncioTestCase: 30c.

   - gh-110392(42): Fix *note tty.setraw(): 17db. and *note
     tty.setcbreak(): 178b.: previously they returned partially modified
     list of the original tty attributes.  *note tty.cfmakeraw(): 17dc.
     and *note tty.cfmakecbreak(): 178c. now make a copy of the list of
     special characters before modifying it.

   - gh-59013(43): Make line number of function breakpoint more precise
     in *note pdb: a5.

   - gh-88434(44): Emit deprecation warning for non-integer numbers in
     *note gettext: 63. functions and methods that consider plural forms
     even if the translation was not found.

   - gh-110395(45): Ensure that *note select.kqueue(): 17dd. objects
     correctly appear as closed in forked children, to prevent
     operations on an invalid file descriptor.

   - gh-110196(46): Add ‘__reduce__’ method to ‘IPv6Address’ in order to
     keep ‘scope_id’

   - gh-109747(47): Improve errors for unsupported look-behind patterns.
     Now re.error is raised instead of OverflowError or RuntimeError for
     too large width of look-behind pattern.

   - gh-109466(48): Add the *note ipaddress.IPv4Address.ipv6_mapped:
     1fb. property, which returns the IPv4-mapped IPv6 address.

   - gh-85098(49): Implement the CLI of the *note symtable: d8. module
     and improve the repr of *note Symbol: 17de.

   - gh-108791(50): Improved error handling in *note pdb: a5. command
     line interface, making it produce more concise error messages.

   - gh-105931(51): Change *note compileall: 20. to only strip the
     stripdir prefix from the full path recorded in the compiled ‘.pyc’
     file, when the prefix matches the start of the full path in its
     entirety.  When the prefix does not match, no stripping is
     performed and a warning to this effect is displayed.

     Previously all path components of the stripdir prefix that matched
     the full path were removed, while those that did not match were
     left alone (including ones interspersed between matching
     components).

   - gh-107431(52): Make the ‘DictProxy’ and ‘ListProxy’ types in *note
     multiprocessing.managers: 97. *note Generic Alias Types: 6b5. for
     ‘[]’ use in typing contexts.

   - gh-72904(53): Add *note glob.translate(): 1ea.  This function
     converts a pathname with shell-style wildcards to a regular
     expression.

   - gh-90026(54): Define ‘USE_XATTRS’ on Cygwin so that XATTR-related
     functions in the *note os: a1. module become available.

   - gh-90890(55): New methods *note mailbox.Maildir.get_info(): 17df,
     *note mailbox.Maildir.set_info(): 17e0, *note
     mailbox.Maildir.get_flags(): 17e1, *note
     mailbox.Maildir.set_flags(): 17e2, *note
     mailbox.Maildir.add_flag(): 17e3, *note
     mailbox.Maildir.remove_flag(): 17e4.  These methods speed up
     accessing a message’s info and/or flags and are useful when it is
     not necessary to access the message’s contents, as when iterating
     over a Maildir to find messages with specific flags.

   - gh-102956(56): Fix returning of empty byte strings after seek in
     zipfile module

   - gh-102895(57): Added a parameter ‘local_exit’ for *note
     code.interact(): 17e5. to prevent ‘exit()’ and ‘quit’ from closing
     ‘sys.stdin’ and raise ‘SystemExit’.

   - gh-97928(58): Change the behavior of ‘tkinter.Text.count()’.  It
     now always returns an integer if one or less counting options are
     specified.  Previously it could return a single count as a 1-tuple,
     an integer (only if option ‘"update"’ was specified) or ‘None’ if
     no items found.  The result is now the same if ‘wantobjects’ is set
     to ‘0’.

   - gh-96954(59): Switch the storage of the unicode codepoint names to
     use a different data-structure, a directed acyclic word graph(60).
     This makes the unicodedata shared library about 440 KiB smaller.
     Contributed by Carl Friedrich Bolz-Tereick using code from the PyPy
     project.

   - gh-73561(61): Omit the interface scope from an IPv6 address when
     used as Host header by *note http.client: 6f.

   - gh-86826(62): ‘zipinfo’ now supports the full range of values in
     the TZ string determined by RFC 8536 and detects all invalid
     formats.  Both Python and C implementations now raise exceptions of
     the same type on invalid data.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111942

   (2) https://github.com/python/cpython/issues/111995

   (3) https://github.com/python/cpython/issues/109538

   (4) https://github.com/python/cpython/issues/111942

   (5) https://github.com/python/cpython/issues/111460

   (6) https://github.com/python/cpython/issues/103791

   (7) https://github.com/python/cpython/issues/111835

   (8) https://github.com/python/cpython/issues/111804

   (9) https://github.com/python/cpython/issues/111841

   (10) https://github.com/python/cpython/issues/111768

   (11) https://github.com/python/cpython/issues/80731

   (12) https://github.com/python/cpython/issues/111541

   (13) https://github.com/python/cpython/issues/111719

   (14) https://github.com/python/cpython/issues/111482

   (15) https://github.com/python/cpython/issues/110894

   (16) https://github.com/python/cpython/issues/111531

   (17) https://github.com/python/cpython/issues/111246

   (18) https://github.com/python/cpython/issues/111356

   (19) https://github.com/python/cpython/issues/66425

   (20) https://github.com/python/cpython/issues/111429

   (21) https://github.com/python/cpython/issues/111342

   (22) https://github.com/python/cpython/issues/68166

   (23) https://github.com/python/cpython/issues/111388

   (24) https://github.com/python/cpython/issues/79033

   (25) https://github.com/python/cpython/issues/111259

   (26) https://github.com/python/cpython/issues/111295

   (27) https://github.com/python/cpython/issues/111253

   (28) https://github.com/python/cpython/issues/111251

   (29) https://github.com/python/cpython/issues/111233

   (30) https://github.com/python/cpython/issues/111230

   (31) https://github.com/python/cpython/issues/111174

   (32) https://github.com/python/cpython/issues/111187

   (33) https://github.com/python/cpython/issues/111159

   (34) https://github.com/python/cpython/issues/110910

   (35) https://github.com/python/cpython/issues/111092

   (36) https://github.com/python/cpython/issues/110944

   (37) https://github.com/python/cpython/issues/110745

   (38) https://github.com/python/cpython/issues/84583

   (39) https://github.com/python/cpython/issues/80675

   (40) https://github.com/python/cpython/issues/110771

   (41) https://github.com/python/cpython/issues/110774

   (42) https://github.com/python/cpython/issues/110392

   (43) https://github.com/python/cpython/issues/59013

   (44) https://github.com/python/cpython/issues/88434

   (45) https://github.com/python/cpython/issues/110395

   (46) https://github.com/python/cpython/issues/110196

   (47) https://github.com/python/cpython/issues/109747

   (48) https://github.com/python/cpython/issues/109466

   (49) https://github.com/python/cpython/issues/85098

   (50) https://github.com/python/cpython/issues/108791

   (51) https://github.com/python/cpython/issues/105931

   (52) https://github.com/python/cpython/issues/107431

   (53) https://github.com/python/cpython/issues/72904

   (54) https://github.com/python/cpython/issues/90026

   (55) https://github.com/python/cpython/issues/90890

   (56) https://github.com/python/cpython/issues/102956

   (57) https://github.com/python/cpython/issues/102895

   (58) https://github.com/python/cpython/issues/97928

   (59) https://github.com/python/cpython/issues/96954

   (60) 
https://en.wikipedia.org/wiki/Deterministic_acyclic_finite_state_automaton

   (61) https://github.com/python/cpython/issues/73561

   (62) https://github.com/python/cpython/issues/86826


File: python.info,  Node: Tests<20>,  Next: Build<20>,  Prev: Library<38>,  Up: Python 3 13 0 alpha 2

1.23.26.3 Tests
...............

   - gh-111808(1): Make the default value of
     ‘test.support.infinite_recursion()’ to be conditional based on
     whether optimizations were used when compiling the interpreter.
     This helps with platforms like WASI whose stack size is greatly
     restricted in debug builds.

   - gh-110722(2): Gathering line coverage of standard libraries within
     the regression test suite is now precise, as well as much faster.
     Patch by Łukasz Langa.

   - gh-110367(3): Make regrtest ‘--verbose3’ option compatible with
     ‘--huntrleaks -jN’ options.  The ‘./python -m test -j1 -R 3:3
     --verbose3’ command now works as expected.  Patch by Victor
     Stinner.

   - gh-111165(4): Remove no longer used functions ‘run_unittest()’ and
     ‘run_doctest()’ from the *note test.support: e4. module.

   - gh-110932(5): Fix regrtest if the ‘SOURCE_DATE_EPOCH’ environment
     variable is defined: use the variable value as the random seed.
     Patch by Victor Stinner.

   - gh-110995(6): test_gdb: Fix detection of gdb built without Python
     scripting support.  Patch by Victor Stinner.

   - gh-110918(7): Test case matching patterns specified by options
     ‘--match’, ‘--ignore’, ‘--matchfile’ and ‘--ignorefile’ are now
     tested in the order of specification, and the last match determines
     whether the test case be run or ignored.

   - gh-108747(8): Add unit test for ‘usercustomize’ and ‘sitecustomize’
     hooks from *note site: c7.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111808

   (2) https://github.com/python/cpython/issues/110722

   (3) https://github.com/python/cpython/issues/110367

   (4) https://github.com/python/cpython/issues/111165

   (5) https://github.com/python/cpython/issues/110932

   (6) https://github.com/python/cpython/issues/110995

   (7) https://github.com/python/cpython/issues/110918

   (8) https://github.com/python/cpython/issues/108747


File: python.info,  Node: Build<20>,  Next: Windows<18>,  Prev: Tests<20>,  Up: Python 3 13 0 alpha 2

1.23.26.4 Build
...............

   - gh-96954(1): Make ‘make regen-unicodedata’ work for out-of-tree
     builds of CPython.

   - gh-112088(2): Add ‘Tools/build/regen-configure.sh’ script to
     regenerate the ‘configure’ with an Ubuntu container image.  The
     ‘quay.io/tiran/cpython_autoconf:271’ container image
     (tiran/cpython_autoconf(3)) is no longer used.  Patch by Victor
     Stinner.

   - gh-111046(4): For wasi-threads, memory is now exported to fix
     compatibility issues with some wasm runtimes.

   - gh-110828(5): AIX 32bit needs ‘-latomic’ to build the ‘_testcapi’
     extension module.

   - gh-85283(6): The ‘errno’, ‘md5’, ‘resource’, ‘winsound’,
     ‘_ctypes_test’, ‘_multiprocessing.posixshmem’, ‘_scproxy’, ‘_stat’,
     ‘_testimportmultiple’ and ‘_uuid’ C extensions are now built with
     the *note limited C API: 399.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96954

   (2) https://github.com/python/cpython/issues/112088

   (3) https://github.com/tiran/cpython_autoconf

   (4) https://github.com/python/cpython/issues/111046

   (5) https://github.com/python/cpython/issues/110828

   (6) https://github.com/python/cpython/issues/85283


File: python.info,  Node: Windows<18>,  Next: macOS<13>,  Prev: Build<20>,  Up: Python 3 13 0 alpha 2

1.23.26.5 Windows
.................

   - gh-111856(1): Fixes *note fstat(): dba. on file systems that do not
     support file ID requests.  This includes FAT32 and exFAT.

   - gh-111293(2): Fix *note os.DirEntry.inode: 17e9. dropping higher 64
     bits of a file id on some filesystems on Windows.

   - gh-110913(3): WindowsConsoleIO now correctly chunks large buffers
     without splitting up UTF-8 sequences.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111856

   (2) https://github.com/python/cpython/issues/111293

   (3) https://github.com/python/cpython/issues/110913


File: python.info,  Node: macOS<13>,  Next: IDLE<16>,  Prev: Windows<18>,  Up: Python 3 13 0 alpha 2

1.23.26.6 macOS
...............

   - gh-59703(1): For macOS framework builds, in ‘getpath.c’ use the
     system ‘dladdr’ function to find the path to the shared library
     rather than depending on deprecated macOS APIs.

   - gh-110950(2): Update macOS installer to include an upstream Tcl/Tk
     fix for the ‘Secure coding is not enabled for restorable state!’
     warning encountered in Tkinter on macOS 14 Sonoma.

   - gh-111015(3): Ensure that IDLE.app and Python Launcher.app are
     installed with appropriate permissions on macOS builds.

   - gh-71383(4): Update macOS installer to include an upstream Tcl/Tk
     fix for the ‘ttk::ThemeChanged’ error encountered in Tkinter.

   - gh-92603(5): Update macOS installer to include a fix accepted by
     upstream Tcl/Tk for a crash encountered after the first *note
     tkinter.Tk(): 173f. instance is destroyed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/59703

   (2) https://github.com/python/cpython/issues/110950

   (3) https://github.com/python/cpython/issues/111015

   (4) https://github.com/python/cpython/issues/71383

   (5) https://github.com/python/cpython/issues/92603


File: python.info,  Node: IDLE<16>,  Next: Tools/Demos<11>,  Prev: macOS<13>,  Up: Python 3 13 0 alpha 2

1.23.26.7 IDLE
..............

   - bpo-35668(1): Add docstrings to the IDLE debugger module.  Fix two
     bugs: initialize ‘Idb.botframe’ (should be in Bdb); in
     ‘Idb.in_rpc_code’, check whether ‘prev_frame’ is ‘None’ before
     trying to use it.  Greatly expand test_debugger.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35668


File: python.info,  Node: Tools/Demos<11>,  Next: C API<20>,  Prev: IDLE<16>,  Up: Python 3 13 0 alpha 2

1.23.26.8 Tools/Demos
.....................

   - gh-111903(1): Argument Clinic now supports the ‘@critical_section’
     directive that instructs Argument Clinic to generate a critical
     section around the function call, which locks the ‘self’ object in
     ‘--disable-gil’ builds.  Patch by Sam Gross.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/111903


File: python.info,  Node: C API<20>,  Prev: Tools/Demos<11>,  Up: Python 3 13 0 alpha 2

1.23.26.9 C API
...............

   - gh-112026(1): Add again the private ‘_PyThreadState_UncheckedGet()’
     function as an alias to the new public *note
     PyThreadState_GetUnchecked(): 374. function.  Patch by Victor
     Stinner.

   - gh-112026(2): Restore the removed
     ‘_PyDict_GetItemStringWithError()’ function.  It is used by numpy.
     Patch by Victor Stinner.

   - gh-112026(3): Restore removed private C API functions, macros and
     structures which have no simple replacement for now:

        * _PyDict_GetItem_KnownHash()

        * _PyDict_NewPresized()

        * _PyHASH_BITS

        * _PyHASH_IMAG

        * _PyHASH_INF

        * _PyHASH_MODULUS

        * _PyHASH_MULTIPLIER

        * _PyLong_Copy()

        * _PyLong_FromDigits()

        * _PyLong_New()

        * _PyLong_Sign()

        * _PyObject_CallMethodId()

        * _PyObject_CallMethodNoArgs()

        * _PyObject_CallMethodOneArg()

        * _PyObject_CallOneArg()

        * _PyObject_EXTRA_INIT

        * _PyObject_FastCallDict()

        * _PyObject_GetAttrId()

        * _PyObject_Vectorcall()

        * _PyObject_VectorcallMethod()

        * _PyStack_AsDict()

        * _PyThread_CurrentFrames()

        * _PyUnicodeWriter structure

        * _PyUnicodeWriter_Dealloc()

        * _PyUnicodeWriter_Finish()

        * _PyUnicodeWriter_Init()

        * _PyUnicodeWriter_Prepare()

        * _PyUnicodeWriter_PrepareKind()

        * _PyUnicodeWriter_WriteASCIIString()

        * _PyUnicodeWriter_WriteChar()

        * _PyUnicodeWriter_WriteLatin1String()

        * _PyUnicodeWriter_WriteStr()

        * _PyUnicodeWriter_WriteSubstring()

        * _PyUnicode_AsString()

        * _PyUnicode_FromId()

        * _PyVectorcall_Function()

        * _Py_IDENTIFIER()

        * _Py_c_abs()

        * _Py_c_diff()

        * _Py_c_neg()

        * _Py_c_pow()

        * _Py_c_prod()

        * _Py_c_quot()

        * _Py_c_sum()

        * _Py_static_string()

        * _Py_static_string_init()

     Patch by Victor Stinner.

   - gh-112026(4): Add again ‘<ctype.h>’ and ‘<unistd.h>’ includes in
     ‘Python.h’, but don’t include them in the limited C API version
     3.13 and newer.  Patch by Victor Stinner.

   - gh-111956(5): Add internal-only one-time initialization API:
     ‘_PyOnceFlag’ and ‘_PyOnceFlag_CallOnce’.

   - gh-111262(6): Add *note PyDict_Pop(): 342. and *note
     PyDict_PopString(): 343. functions: remove a key from a dictionary
     and optionally return the removed value.  This is similar to *note
     dict.pop(): 344, but without the default value and not raising
     *note KeyError: 345. if the key missing.  Patch by Stefan Behnel
     and Victor Stinner.

   - gh-111863(7): Rename ‘Py_NOGIL’ to ‘Py_GIL_DISABLED’.  Patch by
     Hugo van Kemenade.

   - gh-111138(8): Add *note PyList_Extend(): 35e. and *note
     PyList_Clear(): 35f. functions: similar to Python ‘list.extend()’
     and ‘list.clear()’ methods.  Patch by Victor Stinner.

   - gh-108765(9): On Windows, ‘Python.h’ no longer includes the
     ‘<stddef.h>’ standard header file.  If needed, it should now be
     included explicitly.  Patch by Victor Stinner.

   - gh-111569(10): Implement “Python Critical Sections” from PEP
     703(11).  These are macros to help replace the GIL with per-object
     locks in the ‘--disable-gil’ build of CPython.  The macros are
     no-ops in the default build.

   - gh-111506(12): In the limited C API version 3.13, *note
     Py_SET_REFCNT(): 8b2. function is now implemented as an opaque
     function call.  Patch by Victor Stinner.

   - gh-108082(13): Add *note PyErr_FormatUnraisable(): 34f. function.

   - gh-110964(14): Move the undocumented private _PyArg functions and
     _PyArg_Parser structure to internal C API (‘pycore_modsupport.h’).
     Patch by Victor Stinner.

   - gh-110815(15): Support non-ASCII keyword names in *note
     PyArg_ParseTupleAndKeywords(): 386.

   - gh-109587(16): Introduced
     ‘PyUnstable_PerfTrampoline_CompileCode()’,
     ‘PyUnstable_PerfTrampoline_SetPersistAfterFork()’ and
     ‘PyUnstable_CopyPerfMapFile()’.  These functions allow extension
     modules to initialize trampolines eagerly, after the application is
     “warmed up”.  This makes it possible to have perf-trampolines
     running in an always-enabled fashion.

   - gh-85283(17): Add the *note PySys_Audit(): 372. function to the
     limited C API. Patch by Victor Stinner.

   - gh-85283(18): Add *note PyMem_RawMalloc(): 393, *note
     PyMem_RawCalloc(): 394, *note PyMem_RawRealloc(): 395. and *note
     PyMem_RawFree(): 396. to the limited C API. Patch by Victor
     Stinner.

   - gh-106672(19): Functions *note PyDict_GetItem(): 38a, *note
     PyDict_GetItemString(): 38b, *note PyMapping_HasKey(): 382, *note
     PyMapping_HasKeyString(): 384, *note PyObject_HasAttr(): 37e, *note
     PyObject_HasAttrString(): 380, and *note PySys_GetObject(): 38c,
     which clear all errors occurred during calling the function, report
     now them using *note sys.unraisablehook(): 1f7.

   - gh-67565(20): Remove redundant C-contiguity check in ‘getargs.c’,
     *note binascii: 10, *note ssl: d0. and Argument Clinic.  Patched by
     Stefan Krah and Furkan Onder

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/112026

   (2) https://github.com/python/cpython/issues/112026

   (3) https://github.com/python/cpython/issues/112026

   (4) https://github.com/python/cpython/issues/112026

   (5) https://github.com/python/cpython/issues/111956

   (6) https://github.com/python/cpython/issues/111262

   (7) https://github.com/python/cpython/issues/111863

   (8) https://github.com/python/cpython/issues/111138

   (9) https://github.com/python/cpython/issues/108765

   (10) https://github.com/python/cpython/issues/111569

   (11) https://peps.python.org/pep-0703/

   (12) https://github.com/python/cpython/issues/111506

   (13) https://github.com/python/cpython/issues/108082

   (14) https://github.com/python/cpython/issues/110964

   (15) https://github.com/python/cpython/issues/110815

   (16) https://github.com/python/cpython/issues/109587

   (17) https://github.com/python/cpython/issues/85283

   (18) https://github.com/python/cpython/issues/85283

   (19) https://github.com/python/cpython/issues/106672

   (20) https://github.com/python/cpython/issues/67565


File: python.info,  Node: Python 3 13 0 alpha 1,  Next: Python 3 12 0 beta 1,  Prev: Python 3 13 0 alpha 2,  Up: Changelog

1.23.27 Python 3.13.0 alpha 1
-----------------------------

'Release date: 2023-10-13'

* Menu:

* Security: Security<18>.
* Core and Builtins: Core and Builtins<35>.
* Library: Library<39>.
* Documentation: Documentation<18>.
* Tests: Tests<21>.
* Build: Build<21>.
* Windows: Windows<19>.
* macOS: macOS<14>.
* IDLE: IDLE<17>.
* Tools/Demos: Tools/Demos<12>.
* C API: C API<21>.


File: python.info,  Node: Security<18>,  Next: Core and Builtins<35>,  Up: Python 3 13 0 alpha 1

1.23.27.1 Security
..................

   - gh-108310(1): Fixed an issue where instances of *note
     ssl.SSLSocket: 8f3. were vulnerable to a bypass of the TLS
     handshake and included protections (like certificate verification)
     and treating sent unencrypted data as if it were post-handshake TLS
     encrypted data.  Security issue reported as CVE 2023-40217(2) by
     Aapo Oksman.  Patch by Gregory P. Smith.

   - gh-107774(3): PEP 669 specifies that
     ‘sys.monitoring.register_callback’ will generate an audit event.
     Pre-releases of Python 3.12 did not generate the audit event.  This
     is now fixed.

   - gh-102988(4): Reverted the *note email.utils: 50. security
     improvement change released in 3.12beta4 that unintentionally
     caused *note email.utils.getaddresses: 1e1. to fail to parse email
     addresses with a comma in the quoted name field.  See gh-106669(5).

   - gh-99108(6): Refresh our new HACL* built-in *note hashlib: 68. code
     from upstream.  Built-in SHA2 should be faster and an issue with
     SHA3 on 32-bit platforms is fixed.

   - gh-102509(7): Start initializing ‘ob_digit’ during creation of
     *note PyLongObject: 58b. objects.  Patch by Illia Volochii.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/108310

   (2) https://www.cve.org/CVERecord?id=CVE-2023-40217

   (3) https://github.com/python/cpython/issues/107774

   (4) https://github.com/python/cpython/issues/102988

   (5) https://github.com/python/cpython/issues/106669

   (6) https://github.com/python/cpython/issues/99108

   (7) https://github.com/python/cpython/issues/102509


File: python.info,  Node: Core and Builtins<35>,  Next: Library<39>,  Prev: Security<18>,  Up: Python 3 13 0 alpha 1

1.23.27.2 Core and Builtins
...........................

   - gh-110782(1): Fix crash when *note typing.TypeVar: 15d. is
     constructed with a keyword argument.  Patch by Jelle Zijlstra.

   - gh-110752(2): Reset ‘ceval.eval_breaker’ in ‘interpreter_clear()’

   - gh-110721(3): Use the *note traceback: fe. implementation for the
     default ‘PyErr_Display()’ functionality.  Patch by Pablo Galindo

   - gh-110696(4): Fix incorrect error message for invalid argument
     unpacking.  Patch by Pablo Galindo

   - gh-104169(5): Split the tokenizer into two separate directories: -
     One part includes the actual lexeme producing logic and lives in
     ‘Parser/lexer’.  - The second part wraps the lexer according to the
     different tokenization modes we have (string, utf-8, file,
     interactive, readline) and lives in ‘Parser/tokenizer’.

   - gh-110688(6): Remove undocumented ‘test_c_api’ method from *note
     set: 5dc, which was only defined for testing purposes under
     ‘Py_DEBUG’.  Now we have proper CAPI tests.

   - gh-104584(7): Fix a reference leak when running with ‘PYTHONUOPS’
     or *note -X uops: 176. enabled.

   - gh-110514(8): Add ‘PY_THROW’ to *note sys.setprofile(): 154d.
     events

   - gh-110489(9): Optimise *note math.ceil(): 140b. when the input is
     exactly a float, resulting in about a 10% improvement.

   - gh-110455(10): Guard ‘assert(tstate->thread_id > 0)’ with ‘#ifndef
     HAVE_PTHREAD_STUBS’.  This allows for for pydebug builds to work
     under WASI which (currently) lacks thread support.

   - gh-110309(11): Remove unnecessary empty constant nodes in the ast
     of f-string specs.

   - gh-110259(12): Correctly identify the format spec in f-strings
     (with single or triple quotes) that have multiple lines in the
     expression part and include a formatting spec.  Patch by Pablo
     Galindo

   - gh-110237(13): Fix missing error checks for calls to
     ‘PyList_Append’ in ‘_PyEval_MatchClass’.

   - gh-110164(14): regrtest: If the ‘SOURCE_DATE_EPOCH’ environment
     variable is defined, regrtest now disables tests randomization.
     Patch by Victor Stinner.

   - gh-109889(15): Fix the compiler’s redundant NOP detection algorithm
     to skip over NOPs with no line number when looking for the next
     instruction’s lineno.

   - gh-109853(16): ‘sys.path[0]’ is now set correctly for
     subinterpreters.

   - gh-109923(17): Set line number on the ‘POP_TOP’ that follows a
     ‘RETURN_GENERATOR’.

   - gh-105716(18): Subinterpreters now correctly handle the case where
     they have threads running in the background.  Before, such threads
     would interfere with cleaning up and destroying them, as well as
     prevent running another script.

   - gh-109369(19): The internal eval_breaker and supporting flags, plus
     the monitoring version have been merged into a single atomic
     integer to speed up checks.

   - gh-109823(20): Fix bug where compiler does not adjust labels when
     removing an empty basic block which is a jump target.

   - gh-109793(21): The main thread no longer exits prematurely when a
     subinterpreter is cleaned up during runtime finalization.  The bug
     was a problem particularly because, when triggered, the Python
     process would always return with a 0 exitcode, even if it failed.

   - gh-109719(22): Fix missing jump target labels when compiler
     reorders cold/warm blocks.

   - gh-109595(23): Add *note -X cpu_count: 176. command line option to
     override return results of *note os.cpu_count(): 1c5. and *note
     os.process_cpu_count(): 1c4.  This option is useful for users who
     need to limit CPU resources of a container system without having to
     modify the container (application code).  Patch by Donghee Na.

   - gh-109627(24): Fix bug where the compiler does not assign a new
     jump target label to a duplicated small exit block.

   - gh-109596(25): Fix some tokens in the grammar that were incorrectly
     marked as soft keywords.  Also fix some repeated rule names and
     ensure that repeated rules are not allowed.  Patch by Pablo Galindo

   - gh-109496(26): On a Python built in debug mode, *note Py_DECREF():
     572. now calls ‘_Py_NegativeRefcount()’ if the object is a dangling
     pointer to deallocated memory: memory filled with ‘0xDD’ “dead
     byte” by the debug hook on memory allocators.  The fix is to check
     the reference count 'before' checking for ‘_Py_IsImmortal()’.
     Patch by Victor Stinner.

   - gh-107265(27): Deopt opcodes hidden by the executor when base
     opcode is needed

   - gh-109371(28): Deopted instructions correctly for tool
     initialization and modified the incorrect assertion in
     instrumentation, when a previous tool already sets INSTRUCTION
     events

   - gh-105658(29): Fix bug where the line trace of an except block
     ending with a conditional includes an excess event with the line of
     the conditional expression.

   - gh-109219(30): Fix compiling type param scopes that use a name
     which is also free in an inner scope.

   - gh-109351(31): Fix crash when compiling an invalid AST involving a
     named (walrus) expression.

   - gh-109341(32): Fix crash when compiling an invalid AST involving a
     *note ast.TypeAlias: 17f1.

   - gh-109195(33): Fix source location for the ‘LOAD_*’ instruction
     preceding a ‘LOAD_SUPER_ATTR’ to load the ‘super’ global (or
     shadowing variable) so that it encompasses only the name ‘super’
     and not the following parentheses.

   - gh-109256(34): Opcode IDs for specialized opcodes are allocated in
     their own range to improve stability of the IDs for the ‘real’
     opcodes.

   - gh-109216(35): Fix possible memory leak in *note BUILD_MAP: 17f2.

   - gh-109207(36): Fix a SystemError in ‘__repr__’ of symtable entry
     object.

   - gh-109179(37): Fix bug where the C traceback display drops notes
     from *note SyntaxError: 18d.

   - gh-109118(38): Disallow nested scopes (lambdas, generator
     expressions, and comprehensions) within PEP 695 annotation scopes
     that are nested within classes.

   - gh-109156(39): Add tests for de-instrumenting instructions while
     keeping the instrumentation for lines

   - gh-109114(40): Relax the detection of the error message for invalid
     lambdas inside f-strings to not search for arbitrary replacement
     fields to avoid false positives.  Patch by Pablo Galindo

   - gh-105848(41): Add a new *note CALL_KW: 17f3. opcode, used for
     calls containing keyword arguments.  Also, fix a possible crash
     when jumping over method calls in a debugger.

   - gh-109052(42): Use the base opcode when comparing code objects to
     avoid interference from instrumentation

   - gh-109118(43): Fix interpreter crash when a NameError is raised
     inside the type parameters of a generic class.

   - gh-88943(44): Improve syntax error for non-ASCII character that
     follows a numerical literal.  It now points on the invalid
     non-ASCII character, not on the valid numerical literal.

   - gh-108976(45): Fix crash that occurs after de-instrumenting a code
     object in a monitoring callback.

   - gh-108732(46): Make iteration variables of module- and class-scoped
     comprehensions visible to pdb and other tools that use
     ‘frame.f_locals’ again.

   - gh-108959(47): Fix caret placement for error locations for
     subscript and binary operations that involve non-semantic
     parentheses and spaces.  Patch by Pablo Galindo

   - gh-104584(48): Fix a crash when running with ‘PYTHONUOPS’ or *note
     -X uops: 176. enabled and an error occurs during optimization.

   - gh-108727(49): Define ‘tp_dealloc’ for ‘CounterOptimizer_Type’.
     This fixes a segfault on deallocation.

   - gh-108520(50): Fix
     ‘multiprocessing.synchronize.SemLock.__setstate__()’ to properly
     initialize ‘multiprocessing.synchronize.SemLock._is_fork_ctx’.
     This fixes a regression when passing a SemLock across nested
     processes.

     Rename ‘multiprocessing.synchronize.SemLock.is_fork_ctx’ to
     ‘multiprocessing.synchronize.SemLock._is_fork_ctx’ to avoid
     exposing it as public API.

   - gh-108654(51): Restore locals shadowed by an inlined comprehension
     if the comprehension raises an exception.

   - gh-108488(52): Change the initialization of inline cache entries so
     that the cache entry for ‘JUMP_BACKWARD’ is initialized to zero,
     instead of the ‘adaptive_counter_warmup()’ value used for all other
     instructions.  This counter, unique among instructions, counts up
     from zero.

   - gh-108716(53): Turn off deep-freezing of code objects.  Modules are
     still frozen, so that a file system search is not needed for common
     modules.

   - gh-108614(54): Add RESUME_CHECK instruction, to avoid having to
     handle instrumentation, signals, and contexts switches in the tier
     2 execution engine.

   - gh-108487(55): Move an assert that would cause a spurious crash in
     a devious case that should only trigger deoptimization.

   - gh-106176(56): Use a ‘WeakValueDictionary’ to track the lists
     containing the modules each thread is currently importing.  This
     helps avoid a reference leak from keeping the list around longer
     than necessary.  Weakrefs are used as GC can’t interrupt the
     cleanup.

   - gh-105481(57): The regen-opcode build stage was removed and its
     work is now done in regen-cases.

   - gh-107901(58): Fix missing line number on *note JUMP_BACKWARD: 70f.
     at the end of a for loop.

   - gh-108113(59): The *note compile(): 192. built-in can now accept a
     new flag, ‘ast.PyCF_OPTIMIZED_AST’, which is similar to
     ‘ast.PyCF_ONLY_AST’ except that the returned ‘AST’ is optimized
     according to the value of the ‘optimize’ argument.

     *note ast.parse(): 1a8. now accepts an optional argument ‘optimize’
     which is passed on to the *note compile(): 192. built-in.  This
     makes it possible to obtain an optimized ‘AST’.

   - gh-107971(60): Opcode IDs are generated from bytecodes.c instead of
     being hard coded in opcode.py.

   - gh-107944(61): Improve error message for function calls with bad
     keyword arguments.  Patch by Pablo Galindo

   - gh-108390(62): Raise an exception when setting a non-local event
     (‘RAISE’, ‘EXCEPTION_HANDLED’, etc.)  in
     ‘sys.monitoring.set_local_events’.

     Fixes crash when tracing in recursive calls to Python classes.

   - gh-108035(63): Remove the ‘_PyCFrame’ struct, moving the pointer to
     the current interpreter frame back to the threadstate, as it was
     for 3.10 and earlier.  The ‘_PyCFrame’ existed as a performance
     optimization for tracing.  Since PEP 669 has been implemented, this
     optimization no longer applies.

   - gh-91051(64): Fix abort / segfault when using all eight type
     watcher slots, on platforms where ‘char’ is signed by default.

   - gh-106581(65): Fix possible assertion failures and missing
     instrumentation events when ‘PYTHONUOPS’ or *note -X uops: 176. is
     enabled.

   - gh-107526(66): Revert converting ‘vars’, ‘dir’, ‘next’, ‘getattr’,
     and ‘iter’ to argument clinic.

   - gh-84805(67): Autogenerate signature for *note METH_NOARGS: 1523.
     and *note METH_O: 1557. extension functions.

   - gh-107758(68): Make the ‘dump_stack()’ routine used by the
     ‘lltrace’ feature (low-level interpreter debugging) robust against
     recursion by ensuring that it never calls a ‘__repr__’ method
     implemented in Python.  Also make the similar output for Tier-2
     uops appear on ‘stdout’ (instead of ‘stderr’), to match the
     ‘lltrace’ code in ceval.c.

   - gh-107659(69): Add docstrings for *note ctypes.pointer(): 17f4. and
     *note ctypes.POINTER(): 17f5.

   - gh-105848(70): Modify the bytecode so that the actual callable for
     a *note CALL: 70a. is at a consistent position on the stack
     (regardless of whether or not bound-method-calling optimizations
     are active).

   - gh-107674(71): Fixed performance regression in ‘sys.settrace’.

   - gh-107724(72): In pre-release versions of 3.12, up to rc1, the
     sys.monitoring callback function for the ‘PY_THROW’ event was
     missing the third, exception argument.  That is now fixed.

   - gh-84436(73): Skip reference count modifications for many known
     immortal objects.

   - gh-107596(74): Specialize subscripting *note str: 44f. objects by
     *note int: 257. indexes.

   - gh-107080(75): Trace refs builds (‘--with-trace-refs’) were
     crashing when used with isolated subinterpreters.  The problematic
     global state has been isolated to each interpreter.  Other fixing
     the crashes, this change does not affect users.

   - gh-107557(76): Generate the cases needed for the barebones tier 2
     abstract interpreter for optimization passes in CPython.

   - gh-106608(77): Make ‘_PyUOpExecutorObject’ variable length.

   - gh-100964(78): Clear generators’ exception state after ‘return’ to
     break reference cycles.

   - gh-107455(79): Improve error messages when converting an
     incompatible type to *note ctypes.c_char_p: 17f6, *note
     ctypes.c_wchar_p: 17f7. and *note ctypes.c_void_p: 17f8.

   - gh-107263(80): Increase C recursion limit for functions other than
     the main interpreter from 800 to 1500.  This should allow functions
     like ‘list.__repr__’ and ‘json.dumps’ to handle all the inputs that
     they could prior to 3.12

   - gh-104584(81): Fix an issue which caused incorrect inline caches to
     be read when running with ‘PYTHONUOPS’ or *note -X uops: 176.
     enabled.

   - gh-104432(82): Fix potential unaligned memory access on C APIs
     involving returned sequences of ‘char *’ pointers within the *note
     grp: 66. and *note socket: cc. modules.  These were revealed using
     a ‘-fsaniziter=alignment’ build on ARM macOS. Patch by Christopher
     Chavez.

   - gh-106078(83): Isolate ‘_decimal’ (apply PEP 687(84)).  Patch by
     Charlie Zhao.

   - gh-106898(85): Add the exception as the third argument to
     ‘PY_UNIND’ callbacks in ‘sys.monitoring’.  This makes the
     ‘PY_UNWIND’ callback consistent with the other exception handling
     callbacks.

   - gh-106895(86): Raise a ‘ValueError’ when a monitoring callback
     function returns ‘DISABLE’ for events that cannot be disabled
     locally.

   - gh-106897(87): Add a ‘RERAISE’ event to ‘sys.monitoring’, which
     occurs when an exception is reraise, either explicitly by a plain
     ‘raise’ statement, or implicitly in an ‘except’ or ‘finally’ block.

   - gh-77377(88): Ensure that multiprocessing synchronization objects
     created in a fork context are not sent to a different process
     created in a spawn context.  This changes a segfault into an
     actionable RuntimeError in the parent process.

   - gh-106931(89): Statically allocated string objects are now interned
     globally instead of per-interpreter.  This fixes a situation where
     such a string would only be interned in a single interpreter.
     Normal string objects are unaffected.

   - gh-104621(90): Unsupported modules now always fail to be imported.

   - gh-107122(91): Add ‘dbm.ndbm.ndbm.clear()’ to *note dbm.ndbm: 34.
     Patch By Donghee Na.

   - gh-107122(92): Add ‘dbm.gnu.gdbm.clear()’ to *note dbm.gnu: 33.
     Patch By Donghee Na.

   - gh-107015(93): The ASYNC and AWAIT tokens are removed from the
     Grammar, which removes the possibility of making ‘async’ and
     ‘await’ soft keywords when using ‘feature_version<7’ in *note
     ast.parse(): 1a8.

   - gh-106917(94): Fix classmethod-style *note super(): 4de. method
     calls (i.e., where the second argument to ‘super()’, or the implied
     second argument drawn from ‘self/cls’ in the case of zero-arg
     super, is a type) when the target of the call is not a classmethod.

   - gh-105699(95): Python no longer crashes due an infrequent race when
     initializing per-interpreter interned strings.  The crash would
     manifest when the interpreter was finalized.

   - gh-105699(96): Python no longer crashes due to an infrequent race
     in setting ‘Py_FileSystemDefaultEncoding’ and
     ‘Py_FileSystemDefaultEncodeErrors’ (both deprecated), when
     simultaneously initializing two isolated subinterpreters.  Now they
     are only set during runtime initialization.

   - gh-106908(97): Fix various hangs, reference leaks, test failures,
     and tracing/introspection bugs when running with ‘PYTHONUOPS’ or
     *note -X uops: 176. enabled.

   - gh-106092(98): Fix a segmentation fault caused by a use-after-free
     bug in ‘frame_dealloc’ when the trashcan delays the deallocation of
     a ‘PyFrameObject’.

   - gh-106485(99): Reduce the number of materialized instances
     dictionaries by dematerializing them when possible.

   - gh-106719(100): No longer suppress arbitrary errors in the
     ‘__annotations__’ getter and setter in the type and module types.

   - gh-106723(101): Propagate ‘frozen_modules’ to multiprocessing
     spawned process interpreters.

   - gh-104909(102): Split ‘LOAD_ATTR_INSTANCE_VALUE’ into micro-ops.

   - gh-104909(103): Split *note LOAD_GLOBAL: 17f9. specializations into
     micro-ops.

   - gh-106597(104): A new debug structure of offsets has been added to
     the ‘_PyRuntimeState’ that will help out-of-process debuggers and
     profilers to obtain the offsets to relevant interpreter structures
     in a way that is agnostic of how Python was compiled and that
     doesn’t require copying the headers.  Patch by Pablo Galindo

   - gh-106487(105): Allow the 'count' argument of *note str.replace():
     19a. to be a keyword.  Patch by Hugo van Kemenade.

   - gh-96844(106): Improve error message of *note list.remove(): 17fa.
     Patch by Donghee Na.

   - gh-81283(107): Compiler now strips indents from docstrings.  It
     reduces ‘pyc’ file size 5% when the module is heavily documented.
     This change affects to ‘__doc__’ so tools like doctest will be
     affected.

   - gh-106396(108): When the format specification of an f-string
     expression is empty, the parser now generates an empty *note
     ast.JoinedStr: 17fb. node for it instead of an one-element
     ‘ast.JoinedStr’ with an empty string *note ast.Constant: 2b9.

   - gh-100288(109): Specialize *note LOAD_ATTR: 4e1. for
     non-descriptors on the class.  Adds
     ‘LOAD_ATTR_NONDESCRIPTOR_WITH_VALUES’ and
     ‘LOAD_ATTR_NONDESCRIPTOR_NO_DICT’.

   - gh-106008(110): Fix possible reference leaks when failing to
     optimize comparisons with *note None: 678. in the bytecode
     compiler.

   - gh-106145(111): Make ‘end_lineno’ and ‘end_col_offset’ required on
     ‘type_param’ ast nodes.

   - gh-106213(112): Changed the way that Emscripten call trampolines
     work for compatibility with Wasm/JS Promise integration.

   - gh-106182(113): *note sys.getfilesystemencoding(): c7a. and *note
     sys.getfilesystemencodeerrors: d0d. now return interned Unicode
     object.

   - gh-106210(114): Removed Emscripten import trampoline as it was no
     longer necessary for Pyodide.

   - gh-104584(115): Added a new, experimental, tracing optimizer and
     interpreter (a.k.a.  “tier 2”).  This currently pessimizes, so
     don’t use yet – this is infrastructure so we can experiment with
     optimizing passes.  To enable it, pass ‘-Xuops’ or set
     ‘PYTHONUOPS=1’.  To get debug output, set ‘PYTHONUOPSDEBUG=N’ where
     ‘N’ is a debug level (0-4, where 0 is no debug output and 4 is
     excessively verbose).

   - gh-105775(116): *note LOAD_CLOSURE: 17fc. is now a pseudo-op.

   - gh-105730(117): Allow any callable other than type objects as the
     condition predicate in *note BaseExceptionGroup.split(): 168f. and
     *note BaseExceptionGroup.subgroup(): 17d1.

   - gh-105979(118): Fix crash in ‘_imp.get_frozen_object()’ due to
     improper exception handling.

   - gh-106003(119): Add a new *note TO_BOOL: 17fd. instruction, which
     performs boolean conversions for *note POP_JUMP_IF_TRUE: 17fe,
     *note POP_JUMP_IF_FALSE: 17ff, and *note UNARY_NOT: 1800. (which
     all expect exact *note bool: 46b. values now).  Also, modify the
     oparg of *note COMPARE_OP: 973. to include an optional “boolean
     conversion” flag.

   - gh-98931(120): Ensure custom *note SyntaxError: 18d. error messages
     are raised for invalid imports with multiple targets.  Patch by
     Pablo Galindo

   - gh-105724(121): Improve ‘assert’ error messages by providing exact
     error range.

   - gh-105908(122): Fixed bug where gh-99111(123) breaks future import
     ‘barry_as_FLUFL’ in the Python REPL.

   - gh-105840(124): Fix possible crashes when specializing function
     calls with too many ‘__defaults__’.

   - gh-105831(125): Fix an f-string bug, where using a debug expression
     (the ‘=’ sign) that appears in the last line of a file results to
     the debug buffer that holds the expression text being one character
     too small.

   - gh-105800(126): Correctly issue *note SyntaxWarning: 469. in
     f-strings if invalid sequences are used.  Patch by Pablo Galindo

   - gh-105340(127): Include the comprehension iteration variable in
     ‘locals()’ inside a module- or class-scope comprehension.

   - gh-105331(128): Raise *note ValueError: 202. if the ‘delay’
     argument to *note asyncio.sleep(): a7e. is a NaN (matching *note
     time.sleep(): 6a0.).

   - gh-105587(129): The runtime can’t guarantee that immortal objects
     will not be mutated by Extensions.  Thus, this modifies
     _PyStaticObject_CheckRefcnt to warn instead of asserting.

   - gh-105564(130): Don’t include artificil newlines in the ‘line’
     attribute of tokens in the APIs of the *note tokenize: fb. module.
     Patch by Pablo Galindo

   - gh-105549(131): Tokenize separately ‘NUMBER’ and ‘NAME’ tokens that
     are not ambiguous.  Patch by Pablo Galindo.

   - gh-105588(132): Fix an issue that could result in crashes when
     compiling malformed *note ast: 8. nodes.

   - gh-100987(133): Allow objects other than code objects as the
     “executable” in internal frames.  In the long term, this can help
     tools like Cython and PySpy interact more efficiently.  In the
     shorter term, it allows us to perform some optimizations more
     simply.

   - gh-105375(134): Fix bugs in the *note builtins: 12. module where
     exceptions could end up being overwritten.

   - gh-105375(135): Fix bug in the compiler where an exception could
     end up being overwritten.

   - gh-105375(136): Improve error handling in *note
     PyUnicode_BuildEncodingMap(): 1801. where an exception could end up
     being overwritten.

   - gh-105486(137): Change the repr of ‘ParamSpec’ list of args in
     ‘types.GenericAlias’.

   - gh-105678(138): Break the ‘MAKE_FUNCTION’ instruction into two
     parts, ‘MAKE_FUNCTION’ which makes the function and
     ‘SET_FUNCTION_ATTRIBUTE’ which sets the attributes on the function.
     This makes the stack effect of ‘MAKE_FUNCTION’ regular to ease
     optimization and code generation.

   - gh-105435(139): Fix spurious newline character if file ends on a
     comment without a newline.  Patch by Pablo Galindo

   - gh-105390(140): Correctly raise *note tokenize.TokenError: 545.
     exceptions instead of *note SyntaxError: 18d. for tokenize errors
     such as incomplete input.  Patch by Pablo Galindo

   - gh-105259(141): Don’t include newline character for trailing
     ‘NEWLINE’ tokens emitted in the *note tokenize: fb. module.  Patch
     by Pablo Galindo

   - gh-104635(142): Eliminate redundant *note STORE_FAST: 1802.
     instructions in the compiler.  Patch by Donghee Na and Carl Meyer.

   - gh-105324(143): Fix the main function of the *note tokenize: fb.
     module when reading from ‘sys.stdin’.  Patch by Pablo Galindo

   - gh-33092(144): Simplify and speed up interpreter for f-strings.
     Removes ‘FORMAT_VALUE’ opcode.  Add ‘CONVERT_VALUE’,
     ‘FORMAT_SIMPLE’ and ‘FORMAT_WITH_SPEC’ opcode.  Compiler emits more
     efficient sequence for each format expression.

   - gh-105229(145): Remove remaining two-codeunit superinstructions.
     All remaining superinstructions only take a single codeunit,
     simplifying instrumentation and quickening.

   - gh-105235(146): Prevent out-of-bounds memory access during
     ‘mmap.find()’ calls.

   - gh-98963(147): Restore the ability for a subclass of *note
     property: 194. to define ‘__slots__’ or otherwise be dict-less by
     ignoring failures to set a docstring on such a class.  This
     behavior had regressed in 3.12beta1.  An *note AttributeError: 34e.
     where there had not previously been one was disruptive to existing
     code.

   - gh-104812(148): The “pending call” machinery now works for all
     interpreters, not just the main interpreter, and runs in all
     threads, not just the main thread.  Some calls are still only done
     in the main thread, ergo in the main interpreter.  This change does
     not affect signal handling nor the existing public C-API
     (‘Py_AddPendingCall()’), which both still only target the main
     thread.  The new functionality is meant strictly for internal use
     for now, since consequences of its use are not well understood yet
     outside some very restricted cases.  This change brings the
     capability in line with the intention when the state was made
     per-interpreter several years ago.

   - gh-105194(149): Do not escape with backslashes f-string format
     specifiers.  Patch by Pablo Galindo

   - gh-105229(150): Replace some dynamic superinstructions with single
     instruction equivalents.

   - gh-105162(151): Fixed bug in generator.close()/throw() where an
     inner iterator would be ignored when the outer iterator was
     instrumented.

   - gh-105164(152): Ensure annotations are set up correctly if the only
     annotation in a block is within a *note match: 813. block.  Patch
     by Jelle Zijlstra.

   - gh-105148(153): Make ‘_PyASTOptimizeState’ internal to ast_opt.c.
     Make ‘_PyAST_Optimize’ take two integers instead of a pointer to
     this struct.  This avoids the need to include pycore_compile.h in
     ast_opt.c.

   - gh-104799(154): Attributes of *note ast: 8. nodes that are lists
     now default to the empty list if omitted.  This means that some
     code that previously raised *note TypeError: 2c3. when the AST node
     was used will now proceed with the empty list instead.  Patch by
     Jelle Zijlstra.

   - gh-105111(155): Remove the old trashcan macros
     ‘Py_TRASHCAN_SAFE_BEGIN’ and ‘Py_TRASHCAN_SAFE_END’.  They should
     be replaced by the new macros ‘Py_TRASHCAN_BEGIN’ and
     ‘Py_TRASHCAN_END’.

   - gh-105035(156): Fix *note super(): 4de. calls on types with custom
     *note tp_getattro: 1803. implementation (e.g.  meta-types.)

   - gh-105017(157): Show CRLF lines in the tokenize string attribute in
     both NL and NEWLINE tokens.  Patch by Marta Gómez.

   - gh-105013(158): Fix handling of multiline parenthesized lambdas in
     *note inspect.getsource(): 1619.  Patch by Pablo Galindo

   - gh-105017(159): Do not include an additional final ‘NL’ token when
     parsing files having CRLF lines.  Patch by Marta Gómez.

   - gh-104976(160): Ensure that trailing ‘DEDENT’ ‘tokenize.TokenInfo’
     objects emitted by the *note tokenize: fb. module are reported as
     in Python 3.11.  Patch by Pablo Galindo

   - gh-104972(161): Ensure that the ‘line’ attribute in
     ‘tokenize.TokenInfo’ objects in the *note tokenize: fb. module are
     always correct.  Patch by Pablo Galindo

   - gh-104955(162): Fix signature for the new *note
     __release_buffer__(): 1804. slot.  Patch by Jelle Zijlstra.

   - gh-104690(163): Starting new threads and process creation through
     *note os.fork(): 197. during interpreter shutdown (such as from
     *note atexit: c. handlers) is no longer supported.  It can lead to
     race condition between the main Python runtime thread freeing
     thread states while internal *note threading: ed. routines are
     trying to allocate and use the state of just created threads.  Or
     forked children trying to use the mid-shutdown runtime and thread
     state in the child process.

   - gh-104879(164): Fix crash when accessing the ‘__module__’ attribute
     of type aliases defined outside a module.  Patch by Jelle Zijlstra.

   - gh-104825(165): Tokens emitted by the *note tokenize: fb. module do
     not include an implicit ‘\n’ character in the ‘line’ attribute
     anymore.  Patch by Pablo Galindo

   - gh-104770(166): If a generator returns a value upon being closed,
     the value is now returned by *note generator.close(): 15df.

   - gh-89091(167): Raise *note RuntimeWarning: 1bd. for unawaited async
     generator methods like *note asend(): 8e2, *note athrow(): 4fc. and
     *note aclose(): 8e1.  Patch by Kumar Aditya.

   - gh-96663(168): Add a better, more introspect-able error message
     when setting attributes on classes without a ‘__dict__’ and no slot
     member for the attribute.

   - gh-93627(169): Update the Python pickle module implementation to
     match the C implementation of the pickle module.  For objects
     setting reduction methods like *note __reduce_ex__(): 16bf. or
     *note __reduce__(): 9de. to ‘None’, pickling will result in a *note
     TypeError: 2c3.

   - gh-101006(170): Improve error handling when read *note marshal: 8d.
     data.

   - gh-91095(171): Specializes calls to most Python classes.
     Specifically, any class that inherits from ‘object’, or another
     Python class, and does not override ‘__new__’.

     The specialized instruction does the following:

       1. Creates the object (by calling ‘object.__new__’)

       2. Pushes a shim frame to the frame stack (to cleanup after
          ‘__init__’)

       3. Pushes the frame for ‘__init__’ to the frame stack

     Speeds up the instantiation of most Python classes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/110782

   (2) https://github.com/python/cpython/issues/110752

   (3) https://github.com/python/cpython/issues/110721

   (4) https://github.com/python/cpython/issues/110696

   (5) https://github.com/python/cpython/issues/104169

   (6) https://github.com/python/cpython/issues/110688

   (7) https://github.com/python/cpython/issues/104584

   (8) https://github.com/python/cpython/issues/110514

   (9) https://github.com/python/cpython/issues/110489

   (10) https://github.com/python/cpython/issues/110455

   (11) https://github.com/python/cpython/issues/110309

   (12) https://github.com/python/cpython/issues/110259

   (13) https://github.com/python/cpython/issues/110237

   (14) https://github.com/python/cpython/issues/110164

   (15) https://github.com/python/cpython/issues/109889

   (16) https://github.com/python/cpython/issues/109853

   (17) https://github.com/python/cpython/issues/109923

   (18) https://github.com/python/cpython/issues/105716

   (19) https://github.com/python/cpython/issues/109369

   (20) https://github.com/python/cpython/issues/109823

   (21) https://github.com/python/cpython/issues/109793

   (22) https://github.com/python/cpython/issues/109719

   (23) https://github.com/python/cpython/issues/109595

   (24) https://github.com/python/cpython/issues/109627

   (25) https://github.com/python/cpython/issues/109596

   (26) https://github.com/python/cpython/issues/109496

   (27) https://github.com/python/cpython/issues/107265

   (28) https://github.com/python/cpython/issues/109371

   (29) https://github.com/python/cpython/issues/105658

   (30) https://github.com/python/cpython/issues/109219

   (31) https://github.com/python/cpython/issues/109351

   (32) https://github.com/python/cpython/issues/109341

   (33) https://github.com/python/cpython/issues/109195

   (34) https://github.com/python/cpython/issues/109256

   (35) https://github.com/python/cpython/issues/109216

   (36) https://github.com/python/cpython/issues/109207

   (37) https://github.com/python/cpython/issues/109179

   (38) https://github.com/python/cpython/issues/109118

   (39) https://github.com/python/cpython/issues/109156

   (40) https://github.com/python/cpython/issues/109114

   (41) https://github.com/python/cpython/issues/105848

   (42) https://github.com/python/cpython/issues/109052

   (43) https://github.com/python/cpython/issues/109118

   (44) https://github.com/python/cpython/issues/88943

   (45) https://github.com/python/cpython/issues/108976

   (46) https://github.com/python/cpython/issues/108732

   (47) https://github.com/python/cpython/issues/108959

   (48) https://github.com/python/cpython/issues/104584

   (49) https://github.com/python/cpython/issues/108727

   (50) https://github.com/python/cpython/issues/108520

   (51) https://github.com/python/cpython/issues/108654

   (52) https://github.com/python/cpython/issues/108488

   (53) https://github.com/python/cpython/issues/108716

   (54) https://github.com/python/cpython/issues/108614

   (55) https://github.com/python/cpython/issues/108487

   (56) https://github.com/python/cpython/issues/106176

   (57) https://github.com/python/cpython/issues/105481

   (58) https://github.com/python/cpython/issues/107901

   (59) https://github.com/python/cpython/issues/108113

   (60) https://github.com/python/cpython/issues/107971

   (61) https://github.com/python/cpython/issues/107944

   (62) https://github.com/python/cpython/issues/108390

   (63) https://github.com/python/cpython/issues/108035

   (64) https://github.com/python/cpython/issues/91051

   (65) https://github.com/python/cpython/issues/106581

   (66) https://github.com/python/cpython/issues/107526

   (67) https://github.com/python/cpython/issues/84805

   (68) https://github.com/python/cpython/issues/107758

   (69) https://github.com/python/cpython/issues/107659

   (70) https://github.com/python/cpython/issues/105848

   (71) https://github.com/python/cpython/issues/107674

   (72) https://github.com/python/cpython/issues/107724

   (73) https://github.com/python/cpython/issues/84436

   (74) https://github.com/python/cpython/issues/107596

   (75) https://github.com/python/cpython/issues/107080

   (76) https://github.com/python/cpython/issues/107557

   (77) https://github.com/python/cpython/issues/106608

   (78) https://github.com/python/cpython/issues/100964

   (79) https://github.com/python/cpython/issues/107455

   (80) https://github.com/python/cpython/issues/107263

   (81) https://github.com/python/cpython/issues/104584

   (82) https://github.com/python/cpython/issues/104432

   (83) https://github.com/python/cpython/issues/106078

   (84) https://peps.python.org/pep-0687/

   (85) https://github.com/python/cpython/issues/106898

   (86) https://github.com/python/cpython/issues/106895

   (87) https://github.com/python/cpython/issues/106897

   (88) https://github.com/python/cpython/issues/77377

   (89) https://github.com/python/cpython/issues/106931

   (90) https://github.com/python/cpython/issues/104621

   (91) https://github.com/python/cpython/issues/107122

   (92) https://github.com/python/cpython/issues/107122

   (93) https://github.com/python/cpython/issues/107015

   (94) https://github.com/python/cpython/issues/106917

   (95) https://github.com/python/cpython/issues/105699

   (96) https://github.com/python/cpython/issues/105699

   (97) https://github.com/python/cpython/issues/106908

   (98) https://github.com/python/cpython/issues/106092

   (99) https://github.com/python/cpython/issues/106485

   (100) https://github.com/python/cpython/issues/106719

   (101) https://github.com/python/cpython/issues/106723

   (102) https://github.com/python/cpython/issues/104909

   (103) https://github.com/python/cpython/issues/104909

   (104) https://github.com/python/cpython/issues/106597

   (105) https://github.com/python/cpython/issues/106487

   (106) https://github.com/python/cpython/issues/96844

   (107) https://github.com/python/cpython/issues/81283

   (108) https://github.com/python/cpython/issues/106396

   (109) https://github.com/python/cpython/issues/100288

   (110) https://github.com/python/cpython/issues/106008

   (111) https://github.com/python/cpython/issues/106145

   (112) https://github.com/python/cpython/issues/106213

   (113) https://github.com/python/cpython/issues/106182

   (114) https://github.com/python/cpython/issues/106210

   (115) https://github.com/python/cpython/issues/104584

   (116) https://github.com/python/cpython/issues/105775

   (117) https://github.com/python/cpython/issues/105730

   (118) https://github.com/python/cpython/issues/105979

   (119) https://github.com/python/cpython/issues/106003

   (120) https://github.com/python/cpython/issues/98931

   (121) https://github.com/python/cpython/issues/105724

   (122) https://github.com/python/cpython/issues/105908

   (123) https://github.com/python/cpython/issues/99111

   (124) https://github.com/python/cpython/issues/105840

   (125) https://github.com/python/cpython/issues/105831

   (126) https://github.com/python/cpython/issues/105800

   (127) https://github.com/python/cpython/issues/105340

   (128) https://github.com/python/cpython/issues/105331

   (129) https://github.com/python/cpython/issues/105587

   (130) https://github.com/python/cpython/issues/105564

   (131) https://github.com/python/cpython/issues/105549

   (132) https://github.com/python/cpython/issues/105588

   (133) https://github.com/python/cpython/issues/100987

   (134) https://github.com/python/cpython/issues/105375

   (135) https://github.com/python/cpython/issues/105375

   (136) https://github.com/python/cpython/issues/105375

   (137) https://github.com/python/cpython/issues/105486

   (138) https://github.com/python/cpython/issues/105678

   (139) https://github.com/python/cpython/issues/105435

   (140) https://github.com/python/cpython/issues/105390

   (141) https://github.com/python/cpython/issues/105259

   (142) https://github.com/python/cpython/issues/104635

   (143) https://github.com/python/cpython/issues/105324

   (144) https://github.com/python/cpython/issues/33092

   (145) https://github.com/python/cpython/issues/105229

   (146) https://github.com/python/cpython/issues/105235

   (147) https://github.com/python/cpython/issues/98963

   (148) https://github.com/python/cpython/issues/104812

   (149) https://github.com/python/cpython/issues/105194

   (150) https://github.com/python/cpython/issues/105229

   (151) https://github.com/python/cpython/issues/105162

   (152) https://github.com/python/cpython/issues/105164

   (153) https://github.com/python/cpython/issues/105148

   (154) https://github.com/python/cpython/issues/104799

   (155) https://github.com/python/cpython/issues/105111

   (156) https://github.com/python/cpython/issues/105035

   (157) https://github.com/python/cpython/issues/105017

   (158) https://github.com/python/cpython/issues/105013

   (159) https://github.com/python/cpython/issues/105017

   (160) https://github.com/python/cpython/issues/104976

   (161) https://github.com/python/cpython/issues/104972

   (162) https://github.com/python/cpython/issues/104955

   (163) https://github.com/python/cpython/issues/104690

   (164) https://github.com/python/cpython/issues/104879

   (165) https://github.com/python/cpython/issues/104825

   (166) https://github.com/python/cpython/issues/104770

   (167) https://github.com/python/cpython/issues/89091

   (168) https://github.com/python/cpython/issues/96663

   (169) https://github.com/python/cpython/issues/93627

   (170) https://github.com/python/cpython/issues/101006

   (171) https://github.com/python/cpython/issues/91095


File: python.info,  Node: Library<39>,  Next: Documentation<18>,  Prev: Core and Builtins<35>,  Up: Python 3 13 0 alpha 1

1.23.27.3 Library
.................

   - gh-110786(1): *note sysconfig: db.’s CLI now ignores *note
     BrokenPipeError: 109a, making it exit normally if its output is
     being piped and the pipe closes.

   - gh-103480(2): The *note sysconfig: db. module is now a package,
     instead of a single-file module.

   - gh-110733(3): Micro-optimization: Avoid calling ‘min()’, ‘max()’ in
     ‘BaseEventLoop._run_once()’.

   - gh-94597(4): Added *note asyncio.EventLoop: 1806. for use with the
     *note asyncio.run(): 47f. 'loop_factory' kwarg to avoid calling the
     asyncio policy system.

   - gh-110682(5): *note runtime-checkable protocols: 446. used to
     consider ‘__match_args__’ a protocol member in ‘__instancecheck__’
     if it was present on the protocol.  Now, this attribute is ignored
     if it is present.

   - gh-110488(6): Fix a couple of issues in *note
     pathlib.PurePath.with_name(): 1807.: a single dot was incorrectly
     considered a valid name, and in ‘PureWindowsPath’, a name with an
     NTFS alternate data stream, like ‘a:b’, was incorrectly considered
     invalid.

   - gh-110590(7): Fix a bug in ‘_sre.compile()’ where *note TypeError:
     2c3. would be overwritten by *note OverflowError: 888. when the
     'code' argument was a list of non-ints.

   - gh-65052(8): Prevent *note pdb: a5. from crashing when trying to
     display undisplayable objects

   - gh-110519(9): Deprecation warning about non-integer number in *note
     gettext: 63. now always refers to the line in the user code where
     gettext function or method is used.  Previously it could refer to a
     line in ‘gettext’ code.

   - gh-89902(10): Deprecate non-standard format specifier “N” for *note
     decimal.Decimal: 29d.  It was not documented and only supported in
     the C implementation.

   - gh-110378(11): *note contextmanager(): 1247. and *note
     asynccontextmanager(): b42. context managers now close an invalid
     underlying generator object that yields more then one value.

   - gh-106670(12): In *note pdb: a5, set convenience variable
     ‘$_exception’ for post mortem debugging.

   - gh-110365(13): Fix *note termios.tcsetattr(): 1808. bug that was
     overwriting existing errors during parsing integers from ‘term’
     list.

   - gh-109653(14): Slightly improve the import time of several
     standard-library modules by deferring imports of *note warnings:
     112. within those modules.  Patch by Alex Waygood.

   - gh-110273(15): *note dataclasses.replace(): 1809. now raises
     TypeError instead of ValueError if specify keyword argument for a
     field declared with init=False or miss keyword argument for
     required InitVar field.

   - gh-110249(16): Add ‘--inline-caches’ flag to ‘dis’ command line.

   - gh-109653(17): Fix a Python 3.12 regression in the import time of
     *note random: b8.  Patch by Alex Waygood.

   - gh-110222(18): Add support of struct sequence objects in *note
     copy.replace(): 151.  Patched by Xuehai Pan.

   - gh-109649(19): *note multiprocessing: 94, *note concurrent.futures:
     21, *note compileall: 20.: Replace *note os.cpu_count(): 1c5. with
     *note os.process_cpu_count(): 1c4. to select the default number of
     worker threads and processes.  Get the CPU affinity if supported.
     Patch by Victor Stinner.

   - gh-110150(20): Fix base case handling in statistics.quantiles.  Now
     allows a single data point.

   - gh-110036(21): On Windows, multiprocessing ‘Popen.terminate()’ now
     catches *note PermissionError: d6b. and get the process exit code.
     If the process is still running, raise again the ‘PermissionError’.
     Otherwise, the process terminated as expected: store its exit code.
     Patch by Victor Stinner.

   - gh-110038(22): Fixed an issue that caused ‘KqueueSelector.select()’
     to not return all the ready events in some cases when a file
     descriptor is registered for both read and write.

   - gh-110045(23): Update the *note symtable: d8. module to support the
     new scopes introduced by PEP 695(24).

   - gh-88402(25): Add new variables to *note
     sysconfig.get_config_vars(): 1069. on Windows: ‘LIBRARY’,
     ‘LDLIBRARY’, ‘LIBDIR’, ‘SOABI’, and ‘Py_NOGIL’.

   - gh-109631(26): *note re: b9. functions such as *note re.findall():
     1065, *note re.split(): 2a2, *note re.search(): 1272. and *note
     re.sub(): 2a3. which perform short repeated matches can now be
     interrupted by user.

   - gh-109653(27): Reduce the import time of *note email.utils: 50. by
     around 43%.  This results in the import time of *note
     email.message: 44. falling by around 18%, which in turn reduces the
     import time of *note importlib.metadata: 7a. by around 6%.  Patch
     by Alex Waygood.

   - gh-109818(28): Fix *note reprlib.recursive_repr(): 1238. not
     copying ‘__type_params__’ from decorated function.

   - gh-109047(29): *note concurrent.futures: 21.: The 'executor manager
     thread' now catches exceptions when adding an item to the 'call
     queue'.  During Python finalization, creating a new thread can now
     raise *note RuntimeError: 195.  Catch the exception and call
     ‘terminate_broken()’ in this case.  Patch by Victor Stinner.

   - gh-109782(30): Ensure the signature of *note os.path.isdir(): a1d.
     is identical on all platforms.  Patch by Amin Alaee.

   - gh-109653(31): Improve import time of *note functools: 5f. by
     around 13%.  Patch by Alex Waygood.

   - gh-109590(32): *note shutil.which(): 4b7. will prefer files with an
     extension in ‘PATHEXT’ if the given mode includes ‘os.X_OK’ on
     win32.  If no ‘PATHEXT’ match is found, a file without an extension
     in ‘PATHEXT’ can be returned.  This change will have
     ‘shutil.which()’ act more similarly to previous behavior in Python
     3.11.

   - gh-109653(33): Reduce the import time of *note enum: 56. by over
     50%.  Patch by Alex Waygood.

   - gh-109593(34): Avoid deadlocking on a reentrant call to the
     multiprocessing resource tracker.  Such a reentrant call, though
     unlikely, can happen if a GC pass invokes the finalizer for a
     multiprocessing object such as SemLock.

   - gh-109653(35): Reduce the import time of *note typing: 104. by
     around a third.  Patch by Alex Waygood.

   - gh-109649(36): Add *note os.process_cpu_count(): 1c4. function to
     get the number of logical CPUs usable by the calling thread of the
     current process.  Patch by Victor Stinner.

   - gh-74481(37): Add ‘set_error_mode’ related constants in ‘msvcrt’
     module in Python debug build.

   - gh-109613(38): Fix *note os.stat(): 4a3. and *note
     os.DirEntry.stat(): 180a.: check for exceptions.  Previously, on
     Python built in debug mode, these functions could trigger a fatal
     Python error (and abort the process) when a function succeeded with
     an exception set.  Patch by Victor Stinner.

   - gh-109599(39): Expose the type of PyCapsule objects as
     ‘types.CapsuleType’.

   - gh-109109(40): You can now get the raw TLS certificate chains from
     TLS connections via *note ssl.SSLSocket.get_verified_chain(): 16e4.
     and *note ssl.SSLSocket.get_unverified_chain(): 16e5. methods.

     Contributed by Mateusz Nowak.

   - gh-109559(41): Update *note unicodedata: 105. database to Unicode
     15.1.0.

   - gh-109543(42): Remove unnecessary *note hasattr(): 4d5. check
     during *note typing.TypedDict: 162. creation.

   - gh-109495(43): Remove unnecessary extra ‘__slots__’ in *note
     datetime: 1cc.'s pure python implementation to reduce memory size,
     as they are defined in the superclass.  Patch by James Hilton-Balfe

   - gh-109461(44): *note logging: 87.: Use a context manager for lock
     acquisition.

   - gh-109096(45): *note http.server.CGIHTTPRequestHandler: 2a1. has
     been deprecated for removal in 3.15.  Its design is old and the web
     world has long since moved beyond CGI.

   - gh-109409(46): Fix error when it was possible to inherit a frozen
     dataclass from multiple parents some of which were possibly not
     frozen.

   - gh-109375(47): The *note pdb: a5. ‘alias’ command now prevents
     registering aliases without arguments.

   - gh-109319(48): Deprecate the ‘dis.HAVE_ARGUMENT’ field in favour of
     ‘dis.hasarg’.

   - gh-107219(49): Fix a race condition in ‘concurrent.futures’.  When
     a process in the process pool was terminated abruptly (while the
     future was running or pending), close the connection write end.  If
     the call queue is blocked on sending bytes to a worker process,
     closing the connection write end interrupts the send, so the queue
     can be closed.  Patch by Victor Stinner.

   - gh-66143(50): The *note codecs.CodecInfo: 180b. object has been
     made copyable and pickleable.  Patched by Robert Lehmann and Furkan
     Onder.

   - gh-109187(51): *note pathlib.Path.resolve(): 180c. now treats
     symlink loops like other errors: in strict mode, *note OSError:
     41a. is raised, and in non-strict mode, no exception is raised.

   - gh-50644(52): Attempts to pickle or create a shallow or deep copy
     of *note codecs: 1b. streams now raise a TypeError.  Previously,
     copying failed with a RecursionError, while pickling produced wrong
     results that eventually caused unpickling to fail with a
     RecursionError.

   - gh-109174(53): Add support of *note types.SimpleNamespace: 1d1. in
     *note copy.replace(): 151.

   - gh-109164(54): *note pdb: a5.: Replace *note getopt: 61. with *note
     argparse: 6. for parsing command line arguments.

   - gh-109151(55): Enable ‘readline’ editing features in the *note
     sqlite3 command-line interface: 444. (‘python -m sqlite3’).

   - gh-108987(56): Fix *note _thread.start_new_thread(): 196. race
     condition.  If a thread is created during Python finalization, the
     newly spawned thread now exits immediately instead of trying to
     access freed memory and lead to a crash.  Patch by Victor Stinner.

   - gh-108682(57): Enum: require ‘names=()’ or ‘type=...’ to create an
     empty enum using the functional syntax.

   - gh-109033(58): Exceptions raised by os.utime builtin function now
     include the related filename

   - gh-108843(59): Fix an issue in *note ast.unparse(): 8ee. when
     unparsing f-strings containing many quote types.

   - gh-108469(60): *note ast.unparse(): 8ee. now supports new *note
     f-string: 439. syntax introduced in Python 3.12.  Note that the
     f-string quotes are reselected for simplicity under the new syntax.
     (Patch by Steven Sun)

   - gh-108751(61): Add *note copy.replace(): 151. function which allows
     to create a modified copy of an object.  It supports named tuples,
     dataclasses, and many other objects.

   - gh-108682(62): Enum: raise *note TypeError: 2c3. if
     ‘super().__new__()’ is called from a custom ‘__new__’.

   - gh-108278(63): Deprecate passing the callback callable by keyword
     for the following *note sqlite3.Connection: 245. APIs:

        * *note set_authorizer(): 2ab.

        * *note set_progress_handler(): 2ac.

        * *note set_trace_callback(): 2ad.

     The affected parameters will become positional-only in Python 3.15.

     Patch by Erlend E. Aasland.

   - gh-105829(64): Fix concurrent.futures.ProcessPoolExecutor deadlock

   - gh-108295(65): Fix crashes related to use of weakrefs on *note
     typing.TypeVar: 15d.

   - gh-108463(66): Make expressions/statements work as expected in pdb

   - gh-108277(67): Add *note os.timerfd_create(): 211, *note
     os.timerfd_settime(): 212, *note os.timerfd_gettime(): 214, *note
     os.timerfd_settime_ns(): 213, and *note os.timerfd_gettime_ns():
     215. to provide a low level interface for Linux’s timer
     notification file descriptor.

   - gh-107811(68): *note tarfile: de.: extraction of members with
     overly large UID or GID (e.g.  on an OS with 32-bit ‘id_t’) now
     fails in the same way as failing to set the ID.

   - gh-64662(69): Fix support for virtual tables in *note
     sqlite3.Connection.iterdump(): 247.  Patch by Aviv Palivoda.

   - gh-108111(70): Fix a regression introduced in gh-101251(71) for
     3.12, resulting in an incorrect offset calculation in
     ‘gzip.GzipFile.seek()’.

   - gh-108294(72): *note time.sleep(): 6a0. now raises an auditing
     event.

   - gh-108278(73): Deprecate passing name, number of arguments, and the
     callable as keyword arguments, for the following *note
     sqlite3.Connection: 245. APIs:

        * *note create_function(): 2a9.

        * *note create_aggregate(): 2aa.

     The affected parameters will become positional-only in Python 3.15.

     Patch by Erlend E. Aasland.

   - gh-108322(74): Speed-up NormalDist.samples() by using the inverse
     CDF method instead of calling random.gauss().

   - gh-83417(75): Add the ability for venv to create a ‘.gitignore’
     file which causes the created environment to be ignored by Git.  It
     is on by default when venv is called via its CLI.

   - gh-105736(76): Harmonized the pure Python version of *note
     OrderedDict: 5de. with the C version.  Now, both versions set up
     their internal state in ‘__new__’.  Formerly, the pure Python
     version did the set up in ‘__init__’.

   - gh-108083(77): Fix bugs in the constructor of *note
     sqlite3.Connection: 245. and *note sqlite3.Connection.close(): 246.
     where exceptions could be leaked.  Patch by Erlend E. Aasland.

   - gh-107932(78): Fix ‘dis’ module to properly report and display
     bytecode that do not have source lines.

   - gh-105539(79): *note sqlite3: cf. now emits an *note
     ResourceWarning: 244. if a *note sqlite3.Connection: 245. object is
     not ‘closed’ explicitly.  Patch by Erlend E. Aasland.

   - gh-107995(80): The ‘__module__’ attribute on instances of *note
     functools.cached_property: 544. is now set to the name of the
     module in which the cached_property is defined, rather than
     “functools”.  This means that doctests in ‘cached_property’
     docstrings are now properly collected by the *note doctest: 3a.
     module.  Patch by Tyler Smart.

   - gh-107963(81): Fix *note multiprocessing.set_forkserver_preload():
     16a0. to check the given list of modules names.  Patch by Donghee
     Na.

   - gh-106242(82): Fixes *note os.path.normpath(): 1363. to handle
     embedded null characters without truncating the path.

   - gh-81555(83): *note xml.dom.minidom: 122. now only quotes ‘"’ in
     attributes.

   - gh-50002(84): *note xml.dom.minidom: 122. now preserves whitespaces
     in attributes.

   - gh-93057(85): Passing more than one positional argument to *note
     sqlite3.connect(): 2a8. and the *note sqlite3.Connection: 245.
     constructor is deprecated.  The remaining parameters will become
     keyword-only in Python 3.15.  Patch by Erlend E. Aasland.

   - gh-76913(86): Add 'merge_extra' parameter/feature to *note
     logging.LoggerAdapter: 133e.

   - gh-107913(87): Fix possible losses of ‘errno’ and ‘winerror’ values
     in *note OSError: 41a. exceptions if they were cleared or modified
     by the cleanup code before creating the exception object.

   - gh-107845(88): *note tarfile.data_filter(): 430. now takes the
     location of symlinks into account when determining their target, so
     it will no longer reject some valid tarballs with
     ‘LinkOutsideDestinationError’.

   - gh-107812(89): Extend socket’s netlink support to the FreeBSD
     platform.

   - gh-107805(90): Fix signatures of module-level generated functions
     in *note turtle: 101.

   - gh-107782(91): *note pydoc: b5. is now able to show signatures
     which are not representable in Python, e.g.  for ‘getattr’ and
     ‘dict.pop’.

   - gh-56166(92): Deprecate passing optional arguments 'maxsplit',
     'count' and 'flags' in module-level functions *note re.split():
     2a2, *note re.sub(): 2a3. and *note re.subn(): 2a4. as positional.
     They should only be passed by keyword.

   - gh-107710(93): Speed up *note logging.getHandlerNames(): 180d.

   - gh-107715(94): Fix *note doctest.DocTestFinder.find(): 180e. in
     presence of class names with special characters.  Patch by Gertjan
     van Zwieten.

   - gh-100814(95): Passing a callable object as an option value to a
     Tkinter image now raises the expected TclError instead of an
     AttributeError.

   - gh-72684(96): Add *note tkinter: f0. widget methods:
     ‘tk_busy_hold()’, ‘tk_busy_configure()’, ‘tk_busy_cget()’,
     ‘tk_busy_forget()’, ‘tk_busy_current()’, and ‘tk_busy_status()’.

   - gh-106684(97): Raise *note ResourceWarning: 244. when *note
     asyncio.StreamWriter: 180f. is not closed leading to memory leaks.
     Patch by Kumar Aditya.

   - gh-107465(98): Add *note pathlib.Path.from_uri(): 22a. classmethod.

   - gh-107077(99): Seems that in some conditions, OpenSSL will return
     ‘SSL_ERROR_SYSCALL’ instead of ‘SSL_ERROR_SSL’ when a certification
     verification has failed, but the error parameters will still
     contain ‘ERR_LIB_SSL’ and ‘SSL_R_CERTIFICATE_VERIFY_FAILED’.  We
     are now detecting this situation and raising the appropriate
     ‘ssl.SSLCertVerificationError’.  Patch by Pablo Galindo

   - gh-107576(100): Fix *note types.get_original_bases(): 4d1. to only
     return ‘__orig_bases__’ if it is present on ‘cls’ directly.  Patch
     by James Hilton-Balfe.

   - gh-105481(101): Remove ‘opcode.is_pseudo’,
     ‘opcode.MIN_PSEUDO_OPCODE’ and ‘opcode.MAX_PSEUDO_OPCODE’, which
     were added in 3.12, were never documented and were not intended to
     be used externally.

   - gh-105481(102): ‘opcode.ENABLE_SPECIALIZATION’ (which was added in
     3.12 but never documented or intended for external usage) is moved
     to ‘_opcode.ENABLE_SPECIALIZATION’ where tests can access it.

   - gh-107396(103): tarfiles; Fixed use before assignment of
     self.exception for gzip decompression

   - gh-107409(104): Set ‘__wrapped__’ attribute in *note
     reprlib.recursive_repr(): 1238.

   - gh-107406(105): Implement new ‘__repr__()’ method for *note
     struct.Struct: 15ad.  Now it returns ‘Struct(<format repr>)’.

   - gh-107369(106): Optimize *note textwrap.indent(): 276.  It is ~30%
     faster for large input.  Patch by Inada Naoki.

   - gh-78722(107): Fix issue where *note pathlib.Path.iterdir(): 173a.
     did not raise *note OSError: 41a. until iterated.

   - gh-105578(108): Deprecate *note typing.AnyStr: 2b2. in favor of the
     new Type Parameter syntax.  See PEP 695.

   - gh-62519(109): Make *note gettext.pgettext(): a00. search plural
     definitions when translation is not found.

   - gh-107089(110): Shelves opened with *note shelve.open(): 1810. have
     a much faster ‘clear()’ method.  Patch by James Cave.

   - gh-82500(111): Fix overflow on 32-bit systems with *note asyncio:
     a. *note os.sendfile(): b28. implementation.

   - gh-83006(112): Document behavior of *note shutil.disk_usage():
     1171. for non-mounted filesystems on Unix.

   - gh-65495(113): Use lowercase ‘mail from’ and ‘rcpt to’ in
     ‘smptlib.SMTP’.

   - gh-106186(114): Do not report ‘MultipartInvariantViolationDefect’
     defect when the *note email.parser.Parser: 11e1. class is used to
     parse emails with ‘headersonly=True’.

   - gh-105002(115): Fix invalid result from ‘PurePath.relative_to()’
     method when attempting to walk a “‘..’” segment in 'other' with
     'walk_up' enabled.  A *note ValueError: 202. exception is now
     raised in this case.

   - gh-106739(116): Add the ‘rtype_cache’ to the warning message (as an
     addition to the type of leaked objects and the number of leaked
     objects already included in the message) to make debugging leaked
     objects easier when the multiprocessing resource tracker process
     finds leaked objects at shutdown.  This helps more quickly identify
     what was leaked and/or why the leaked object was not properly
     cleaned up.

   - gh-106751(117): Optimize ‘SelectSelector.select()’ for many
     iteration case.  Patch By Donghee Na.

   - gh-106751(118): Optimize ‘_PollLikeSelector.select()’ for many
     iteration case.

   - gh-106751(119): Optimize ‘KqueueSelector.select()’ for many
     iteration case.  Patch By Donghee Na.

   - gh-106831(120): Fix potential missing ‘NULL’ check of
     ‘d2i_SSL_SESSION’ result in ‘_ssl.c’.

   - gh-105481(121): The various opcode lists in the *note dis: 38.
     module are now generated from bytecodes.c instead of explicitly
     constructed in opcode.py.

   - gh-106727(122): Make *note inspect.getsource(): 1619. smarter for
     class for same name definitions

   - gh-106789(123): Remove import of *note pprint: ae. from *note
     sysconfig: db.

   - gh-105726(124): Added ‘__slots__’ to *note
     contextlib.AbstractContextManager: cb1. and *note
     contextlib.AbstractAsyncContextManager: b43. so that child classes
     can use ‘__slots__’.

   - gh-106774(125): Update the bundled copy of pip to version 23.2.1.

   - gh-106751(126): *note selectors: c2.: Optimize
     ‘EpollSelector.select()’ code by moving some code outside of the
     loop.

   - gh-106752(127): Fixed several bugs in zipfile.Path, including: in
     ‘zipfile.Path.match()’, Windows separators are no longer honored
     (and never were meant to be); Fixed
     ‘name’/‘suffix’/‘suffixes’/‘stem’ operations when no filename is
     present and the Path is not at the root of the zipfile; Reworked
     glob for performance and more correct matching behavior.

   - gh-105293(128): Remove call to ‘SSL_CTX_set_session_id_context’
     during client side context creation in the *note ssl: d0. module.

   - gh-106734(129): Disable tab completion in multiline mode of *note
     pdb: a5.

   - gh-105481(130): Expose opcode metadata through ‘_opcode’.

   - gh-106670(131): Add the new ‘exceptions’ command to the Pdb
     debugger.  It makes it possible to move between chained exceptions
     when using post mortem debugging.

   - gh-106602(132): Add __copy__ and __deepcopy__ in *note enum: 56.

   - gh-106664(133): *note selectors: c2.: Add ‘_SelectorMapping.get()’
     method and optimize ‘_SelectorMapping.__getitem__()’.

   - gh-106628(134): Speed up parsing of emails by about 20% by not
     compiling a new regular expression for every single email.

   - gh-89427(135): Set the environment variable ‘VIRTUAL_ENV_PROMPT’ at
     *note venv: 111. activation, even when ‘VIRTUAL_ENV_DISABLE_PROMPT’
     is set.

   - gh-106530(136): Revert a change to *note colorsys.rgb_to_hls():
     1811. that caused division by zero for certain almost-white inputs.
     Patch by Terry Jan Reedy.

   - gh-106584(137): Fix exit code for ‘unittest’ if all tests are
     skipped.  Patch by Egor Eliseev.

   - gh-106566(138): Optimize ‘(?!)’ (pattern which always fails) in
     regular expressions.

   - gh-106554(139): *note selectors: c2.: Reduce Selector overhead by
     using a ‘dict.get()’ to lookup file descriptors.

   - gh-106558(140): Remove ref cycle in callers of ‘convert_to_error()’
     by deleting ‘result’ from scope in a ‘finally’ block.

   - gh-100502(141): Add ‘pathlib.PurePath.pathmod’ class attribute that
     stores the implementation of *note os.path: a2. used for low-level
     path operations: either ‘posixpath’ or ‘ntpath’.

   - gh-106527(142): Reduce overhead to add and remove *note asyncio: a.
     readers and writers.

   - gh-106524(143): Fix crash in ‘_sre.template()’ with templates
     containing invalid group indices.

   - gh-106531(144): Removed ‘_legacy’ and the names it provided from
     ‘importlib.resources’: ‘Resource’, ‘contents’, ‘is_resource’,
     ‘open_binary’, ‘open_text’, ‘path’, ‘read_binary’, and ‘read_text’.

   - gh-106052(145): *note re: b9. module: fix the matching of
     possessive quantifiers in the case of a subpattern containing
     backtracking.

   - gh-106510(146): Improve debug output for atomic groups in regular
     expressions.

   - gh-106503(147): Fix ref cycle in ‘asyncio._SelectorSocketTransport’
     by removing ‘_write_ready’ in ‘close’.

   - gh-105497(148): Fix flag mask inversion when unnamed flags exist.

   - gh-90876(149): Prevent ‘multiprocessing.spawn’ from failing to
     'import' in environments where ‘sys.executable’ is ‘None’.  This
     regressed in 3.11 with the addition of support for path-like
     objects in multiprocessing.

   - gh-106403(150): Instances of *note typing.TypeVar: 15d, *note
     typing.ParamSpec: 15e, *note typing.ParamSpecArgs: 7ca, *note
     typing.ParamSpecKwargs: 7cb, and *note typing.TypeVarTuple: 15f.
     once again support weak references, fixing a regression introduced
     in Python 3.12.0 beta 1.  Patch by Jelle Zijlstra.

   - gh-89812(151): Add private ‘pathlib._PathBase’ class, which
     provides experimental support for virtual filesystems, and may be
     made public in a future version of Python.

   - gh-106292(152): Check for an instance-dict cached value in the
     ‘__get__()’ method of *note functools.cached_property(): 544.  This
     better matches the pre-3.12 behavior and improves compatibility for
     users subclassing ‘functools.cached_property()’ and adding a
     ‘__set__()’ method.

   - gh-106350(153): Detect possible memory allocation failure in the
     libtommath function ‘mp_init()’ used by the ‘_tkinter’ module.

   - gh-106330(154): Fix incorrect matching of empty paths in *note
     pathlib.PurePath.match(): 4af.  This bug was introduced in Python
     3.12.0 beta 1.

   - gh-106309(155): Deprecate *note typing.no_type_check_decorator():
     2b1.  No major type checker ever added support for this decorator.
     Patch by Alex Waygood.

   - gh-102541(156): Make ‘pydoc.doc()’ catch bad module *note
     ImportError: 41c. when output stream is not ‘None’.

   - gh-106263(157): Fix crash when calling ‘repr’ with a manually
     constructed SignalDict object.  Patch by Charlie Zhao.

   - gh-106236(158): Replace ‘assert’ statements with ‘raise
     RuntimeError’ in *note threading: ed, so that ‘_DummyThread’ cannot
     be joined even with ‘-OO’.

   - gh-106238(159): Fix rare concurrency bug in lock acquisition by the
     logging package.

   - gh-106152(160): Added PY_THROW event hook for *note cProfile: 27.
     for generators

   - gh-106075(161): Added ‘asyncio.taskgroups.__all__’ to
     ‘asyncio.__all__’ for export in star imports.

   - gh-104527(162): Zipapp will now skip over appending an archive to
     itself.

   - gh-106046(163): Improve the error message from *note os.fspath():
     c74. if called on an object where ‘__fspath__’ is set to ‘None’.
     Patch by Alex Waygood.

   - gh-105987(164): Fix crash due to improper reference counting in
     *note asyncio: a. eager task factory internal routines.

   - gh-105974(165): Fix bug where a *note typing.Protocol: 264. class
     that had one or more non-callable members would raise *note
     TypeError: 2c3. when *note issubclass(): 7c5. was called against
     it, even if it defined a custom ‘__subclasshook__’ method.  The
     behaviour in Python 3.11 and lower – which has now been restored –
     was not to raise ‘TypeError’ in these situations if a custom
     ‘__subclasshook__’ method was defined.  Patch by Alex Waygood.

   - gh-96145(166): Reverted addition of ‘json.AttrDict’.

   - gh-89812(167): Add *note pathlib.UnsupportedOperation: 227, which
     is raised instead of *note NotImplementedError: 228. when a path
     operation isn’t supported.

   - gh-105808(168): Fix a regression introduced in gh-101251(169) for
     3.12, causing ‘gzip.GzipFile.flush()’ to not flush the compressor
     (nor pass along the ‘zip_mode’ argument).

   - gh-105481(170): *note stack_effect(): f69. no longer raises an
     exception if an ‘oparg’ is provided for an ‘opcode’ that doesn’t
     use its arg, or when it is not provided for an ‘opcode’ that does
     use it.  In the latter case, the stack effect is returned for
     ‘oparg=0’.

   - gh-104799(171): Enable *note ast.unparse(): 8ee. to unparse
     function and class definitions created without the new
     ‘type_params’ field from PEP 695(172).  Patch by Jelle Zijlstra.

   - gh-105793(173): Add 'follow_symlinks' keyword-only argument to
     *note pathlib.Path.is_dir(): 230. and *note is_file(): 22f,
     defaulting to ‘True’.

   - gh-105570(174): Deprecate two methods of creating *note
     typing.TypedDict: 162. classes with 0 fields using the functional
     syntax: ‘TD = TypedDict("TD")’ and ‘TD = TypedDict("TD", None)’.
     Both will be disallowed in Python 3.15.  To create a ‘TypedDict’
     class with 0 fields, either use ‘class TD(TypedDict): pass’ or ‘TD
     = TypedDict("TD", {})’.

   - gh-105745(175): Fix ‘webbrowser.Konqueror.open’ method.

   - gh-105733(176): *note ctypes: 2a.: Deprecate undocumented
     ‘ctypes.SetPointerType()’ and ‘ctypes.ARRAY()’ functions.  Patch by
     Victor Stinner.

   - gh-105687(177): Remove deprecated ‘re.template’, ‘re.T’,
     ‘re.TEMPLATE’, ‘sre_constans.SRE_FLAG_TEMPLATE’.

   - gh-105684(178): Supporting *note asyncio.Task.set_name(): 9e8. is
     now mandatory for third party task implementations.  The
     undocumented ‘_set_task_name()’ function (deprecated since 3.8) has
     been removed.  Patch by Kumar Aditya.

   - gh-105375(179): Fix a bug in ‘_Unpickler_SetInputStream()’ where an
     exception could end up being overwritten in case of failure.

   - gh-105626(180): Change the default return value of *note
     http.client.HTTPConnection.get_proxy_response_headers(): 1812. to
     be ‘None’ and not ‘{}’.

   - gh-105375(181): Fix bugs in *note sys: d9. where exceptions could
     end up being overwritten because of deferred error handling.

   - gh-105605(182): Harden ‘pyexpat’ error handling during module
     initialisation to prevent exceptions from possibly being
     overwritten, and objects from being dereferenced twice.

   - gh-105375(183): Fix bug in *note decimal: 36. where an exception
     could end up being overwritten.

   - gh-105375(184): Fix bugs in ‘_datetime’ where exceptions could be
     overwritten in case of module initialisation failure.

   - gh-105375(185): Fix bugs in ‘_ssl’ initialisation which could lead
     to leaked references and overwritten exceptions.

   - gh-105375(186): Fix a bug in *note array.array: 1a0. where an
     exception could end up being overwritten.

   - gh-105375(187): Fix bugs in ‘_ctypes’ where exceptions could end up
     being overwritten.

   - gh-105375(188): Fix a bug in the *note posix: ad. module where an
     exception could be overwritten.

   - gh-105375(189): Fix bugs in ‘_elementtree’ where exceptions could
     be overwritten.

   - gh-105375(190): Fix bugs in *note zoneinfo: 134. where exceptions
     could be overwritten.

   - gh-105375(191): Fix bugs in *note errno: 57. where exceptions could
     be overwritten.

   - gh-105566(192): Deprecate creating a *note typing.NamedTuple: 2b0.
     class using keyword arguments to denote the fields (‘NT =
     NamedTuple("NT", x=int, y=str)’).  This will be disallowed in
     Python 3.15.  Use the class-based syntax or the functional syntax
     instead.

     Two methods of creating ‘NamedTuple’ classes with 0 fields using
     the functional syntax are also deprecated, and will be disallowed
     in Python 3.15: ‘NT = NamedTuple("NT")’ and ‘NT = NamedTuple("NT",
     None)’.  To create a ‘NamedTuple’ class with 0 fields, either use
     ‘class NT(NamedTuple): pass’ or ‘NT = NamedTuple("NT", [])’.

   - gh-105545(193): Remove deprecated in 3.11
     ‘webbrowser.MacOSXOSAScript._name’ attribute.

   - gh-105497(194): Fix flag inversion when alias/mask members exist.

   - gh-105509(195): *note typing.Annotated: 947. is now implemented as
     an instance of ‘typing._SpecialForm’ rather than a class.  This
     should have no user-facing impact for users of the *note typing:
     104. module public API.

   - gh-105375(196): Fix bugs in *note pickle: a6. where exceptions
     could be overwritten.

   - gh-70303(197): Emit *note FutureWarning: 418. from *note
     pathlib.Path.glob(): 22d. and *note rglob(): 22e. if the given
     pattern ends with “‘**’”.  In a future Python release, patterns
     with this ending will match both files and directories.  Add a
     trailing slash to only match directories.

   - gh-105375(198): Fix a bug in *note sqlite3: cf. where an exception
     could be overwritten in the *note collation: 679. callback.

   - gh-105382(199): Remove 'cafile', 'capath' and 'cadefault'
     parameters of the *note urllib.request.urlopen(): 293. function,
     deprecated in Python 3.6.  Patch by Victor Stinner.

   - gh-105376(200): *note logging: 87.: Remove undocumented and
     untested ‘Logger.warn()’ and ‘LoggerAdapter.warn()’ methods and
     ‘logging.warn()’ function.  Deprecated since Python 3.3, they were
     aliases to the *note logging.Logger.warning(): 1813. method,
     ‘logging.LoggerAdapter.warning()’ method and *note
     logging.warning(): 2ff. function.  Patch by Victor Stinner.

   - gh-105332(201): Revert pickling method from by-name back to
     by-value.

   - gh-104554(202): Add RTSPS scheme support in urllib.parse

   - gh-105292(203): Add option to *note
     traceback.format_exception_only(): 854. to recurse into the nested
     exception of a *note BaseExceptionGroup: 25f.

   - gh-105280(204): Fix bug where ‘isinstance([],
     collections.abc.Mapping)’ could evaluate to ‘True’ if garbage
     collection happened at the wrong time.  The bug was caused by
     changes to the implementation of *note typing.Protocol: 264. in
     Python 3.12.

   - gh-80480(205): *note array: 7.: Add ‘'w'’ typecode that represents
     ‘Py_UCS4’.

   - gh-105239(206): Fix longstanding bug where ‘issubclass(object,
     typing.Protocol)’ would evaluate to ‘True’ in some edge cases.
     Patch by Alex Waygood.

   - gh-104310(207): In the beta 1 release we added a utility function
     for extension module authors, to use when testing their module for
     support in multiple interpreters or under a per-interpreter GIL.
     The name of that function has changed from
     ‘allowing_all_extensions’ to
     ‘_incompatible_extension_module_restrictions’.  The default for the
     “disable_check” argument has change from ‘True’ to ‘False’, to
     better match the new function name.

   - gh-105080(208): Fixed inconsistent signature on derived classes for
     *note inspect.signature(): 73b.

   - gh-105144(209): Fix a recent regression in the *note typing: 104.
     module.  The regression meant that doing ‘class Foo(X,
     typing.Protocol)’, where ‘X’ was a class that had *note
     abc.ABCMeta: f4f. as its metaclass, would then cause subsequent
     ‘isinstance(1, X)’ calls to erroneously raise *note TypeError: 2c3.
     Patch by Alex Waygood.

   - gh-62948(210): The *note io.IOBase: 1f5. finalizer now logs the
     ‘close()’ method errors with *note sys.unraisablehook: 1f7.
     Previously, errors were ignored silently by default, and only
     logged in *note Python Development Mode: 1f8. or on *note Python
     built on debug mode: 1f9.  Patch by Victor Stinner.

   - gh-105096(211): *note wave: 113.: Deprecate the ‘getmark()’,
     ‘setmark()’ and ‘getmarkers()’ methods of the *note wave.Wave_read:
     2b6. and *note wave.Wave_write: 2b7. classes.  They will be removed
     in Python 3.15.  Patch by Victor Stinner.

   - gh-104992(212): Remove the untested and undocumented
     ‘unittest.TestProgram.usageExit()’ method, deprecated in Python
     3.11.  Patch by Hugo van Kemenade.

   - gh-104996(213): Improve performance of *note pathlib.PurePath: 4a9.
     initialisation by deferring joining of paths when multiple
     arguments are given.

   - gh-101588(214): Deprecate undocumented copy/deepcopy/pickle support
     for itertools.

   - gh-103631(215): Fix
     ‘pathlib.PurePosixPath(pathlib.PureWindowsPath(...))’ not
     converting path separators to restore 3.11 compatible behavior.

   - gh-104947(216): Make comparisons between *note
     pathlib.PureWindowsPath: 1814. objects consistent across Windows
     and Posix to match 3.11 behavior.

   - gh-104773(217): PEP 594(218): Remove the ‘audioop’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(219): PEP 594(220): Remove the ‘aifc’ module, deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(221): PEP 594(222): Remove the ‘uu’ module, deprecated in
     Python 3.11.  Patch by Victor Stinner.

   - gh-104935(223): Fix bugs with the interaction between *note
     typing.runtime_checkable(): 446. and *note typing.Generic: 15fb.
     that were introduced by the PEP 695(224) implementation.  Patch by
     Jelle Zijlstra.

   - gh-104773(225): PEP 594(226): Remove the ‘crypt’ module and its
     private ‘_crypt’ extension, deprecated in Python 3.11.  Patch by
     Victor Stinner.

   - gh-104773(227): PEP 594(228): Remove the ‘nis’ module, deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104898(229): Add missing *note __slots__: 153a. to *note
     os.PathLike: c72.

   - gh-104773(230): PEP 594(231): Remove the ‘xdrlib’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(232): PEP 594(233): Remove the ‘nntplib’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104886(234): Remove the undocumented
     ‘configparser.LegacyInterpolation’ class, deprecated in the
     docstring since Python 3.2, and with a deprecation warning since
     Python 3.11.  Patch by Hugo van Kemenade.

   - gh-104786(235): Remove kwargs-based *note typing.TypedDict: 162.
     creation

   - gh-104876(236): Remove the ‘turtle.RawTurtle.settiltangle()’
     method, deprecated in docs since Python 3.1 and with a deprecation
     warning since Python 3.11.  Patch by Hugo van Kemenade.

   - gh-104773(237): PEP 594(238): Removed the ‘msilib’ package,
     deprecated in Python 3.11.

   - gh-104773(239): PEP 594(240): Remove the ‘spwd’ module, deprecated
     in Python 3.11: the python-pam(241) project can be used instead.
     Patch by Victor Stinner.

   - gh-75552(242): Removed the ‘tkinter.tix’ module, deprecated since
     Python 3.6.

   - gh-104773(243): PEP 594(244): Remove the ‘chunk’ module, deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(245): PEP 594(246): Remove the ‘mailcap’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(247): PEP 594(248): Remove the ‘sunau’ module, deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104780(249): PEP 594(250): Remove the ‘ossaudiodev’ module,
     deprecated in Python 3.11.  Patch Victor Stinner.

   - gh-104773(251): PEP 594(252): Remove the ‘pipes’ module, deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104873(253): Add *note typing.get_protocol_members(): 263. to
     return the set of members defining a *note typing.Protocol: 264.
     Add *note typing.is_protocol(): 265. to check whether a class is a
     ‘typing.Protocol’.  Patch by Jelle Zijlstra.

   - gh-104874(254): Document the ‘__name__’ and ‘__supertype__’
     attributes of *note typing.NewType: d1c.  Patch by Jelle Zijlstra.

   - gh-104835(255): Removed the following *note unittest: 106.
     functions, deprecated in Python 3.11:

        * ‘unittest.findTestCases()’

        * ‘unittest.makeSuite()’

        * ‘unittest.getTestCaseNames()’

     Use *note TestLoader: 28e. methods instead:

        * *note unittest.TestLoader.loadTestsFromModule(): 28f.

        * *note unittest.TestLoader.loadTestsFromTestCase(): 290.

        * *note unittest.TestLoader.getTestCaseNames(): 291.

     Patch by Hugo van Kemenade.

   - gh-104804(256): Remove the untested and undocumented *note
     webbrowser: 115. ‘MacOSX’ class, deprecated in Python 3.11.  Patch
     by Hugo van Kemenade.

   - gh-83863(257): Support for using *note pathlib.Path: 229. objects
     as context managers has been removed.  Before Python 3.9, exiting
     the context manager marked a path as “closed”, which caused some
     (but not all!)  methods to raise when called.  Since Python 3.9,
     using a path as a context manager does nothing.

   - gh-104799(258): Adjust the location of the (see PEP 695(259))
     ‘type_params’ field on *note ast.ClassDef: 1815, *note
     ast.AsyncFunctionDef: 1816, and *note ast.FunctionDef: 1817. to
     better preserve backward compatibility.  Patch by Jelle Zijlstra

   - gh-104797(260): Allow *note typing.Protocol: 264. classes to
     inherit from *note collections.abc.Buffer: 2e9.  Patch by Jelle
     Zijlstra.

   - gh-104783(261): Remove ‘locale.resetlocale()’ function deprecated
     in Python 3.11.  Patch by Victor Stinner.

   - gh-104780(262): Remove the ‘2to3’ program and the ‘lib2to3’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(263): PEP 594(264): Remove the ‘telnetlib’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(265): PEP 594(266): Remove the ‘imghdr’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(267): PEP 594(268): Remove the ‘cgi’ and ‘cgitb’ modules,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104773(269): PEP 594(270): Remove the ‘sndhdr’ module,
     deprecated in Python 3.11.  Patch by Victor Stinner.

   - gh-104372(271): On Linux where *note subprocess: d6. can use the
     ‘vfork()’ syscall for faster spawning, prevent the parent process
     from blocking other threads by dropping the GIL while it waits for
     the vfork’ed child process ‘exec()’ outcome.  This prevents
     spawning a binary from a slow filesystem from blocking the rest of
     the application.

   - gh-99108(272): We now release the GIL around built-in *note
     hashlib: 68. computations of reasonable size for the SHA families
     and MD5 hash functions, matching what our OpenSSL backed hash
     computations already does.

   - gh-102613(273): Improve performance of *note pathlib.Path.glob():
     22d. when expanding a pattern with a non-terminal “‘**’” component
     by filtering walked paths through a regular expression, rather than
     calling *note os.scandir(): a6d. more than once on each directory.

   - gh-104399(274): Prepare the ‘_tkinter’ module for building with Tcl
     9.0 and future libtommath by replacing usage of deprecated
     functions ‘mp_to_unsigned_bin_n()’ and ‘mp_unsigned_bin_size()’
     when necessary.

   - gh-102676(275): Add fields ‘start_offset’, ‘cache_offset’,
     ‘end_offset’, ‘baseopname’, ‘baseopcode’, ‘jump_target’ and ‘oparg’
     to *note dis.Instruction: 1da.

   - gh-103558(276): Fixed ‘parent’ argument validation mechanism of
     *note argparse: 6.  Improved test coverage.

   - gh-103464(277): Provide helpful usage messages when parsing
     incorrect *note pdb: a5. commands.

   - gh-103384(278): Generalize the regex pattern
     ‘BaseConfigurator.INDEX_PATTERN’ to allow spaces and
     non-alphanumeric characters in keys.

   - gh-103124(279): Added multiline statement support for *note pdb:
     a5.

   - gh-101162(280): Forbid using ‘builtins.issubclass()’ with *note
     types.GenericAlias: 7f0. as the first argument.

   - gh-103200(281): Fix cache repopulation semantics of
     zipimport.invalidate_caches().  The cache is now repopulated upon
     retrieving files with an invalid cache, not when the cache is
     invalidated.

   - gh-100061(282): Fix a bug that causes wrong matches for regular
     expressions with possessive qualifier.

   - gh-77609(283): Add 'follow_symlinks' argument to *note
     pathlib.Path.glob(): 22d. and *note rglob(): 22e, defaulting to
     false.

   - gh-102541(284): Hide traceback in *note help(): 8e0. prompt, when
     import failed.

   - gh-102120(285): Added a stream mode to ‘tarfile’ that allows for
     reading archives without caching info about the inner files.

   - gh-102029(286): Deprecate passing any arguments to *note
     threading.RLock(): 2de.

   - gh-88233(287): Refactored ‘zipfile._strip_extra’ to use higher
     level abstractions for extras instead of a heavy-state loop.

   - gh-102024(288): Reduce calls of ‘_idle_semaphore.release()’ in
     ‘concurrent.futures.thread._worker()’.

   - gh-73435(289): Add support for recursive wildcards in *note
     pathlib.PurePath.match(): 4af.

   - gh-84867(290): *note unittest.TestLoader: 28e. no longer loads test
     cases from exact *note unittest.TestCase: 451. and *note
     unittest.FunctionTestCase: 1818. classes.

   - gh-99203(291): Restore following CPython <= 3.10.5 behavior of
     *note shutil.make_archive(): 4b6.: do not create an empty archive
     if ‘root_dir’ is not a directory, and, in that case, raise *note
     FileNotFoundError: 42e. or *note NotADirectoryError: 1098.
     regardless of ‘format’ choice.  Beyond the brought-back behavior,
     the function may now also raise these exceptions in ‘dry_run’ mode.

   - gh-80480(292): Emit *note DeprecationWarning: 1a5. for *note array:
     7.’s ‘'u'’ type code, deprecated in docs since Python 3.3.

   - gh-94924(293): *note unittest.mock.create_autospec(): 1712. now
     properly returns coroutine functions compatible with *note
     inspect.iscoroutinefunction(): 2e4.

   - gh-94777(294): Fix hanging *note multiprocessing: 94.
     ‘ProcessPoolExecutor’ when a child process crashes while data is
     being written in the call queue.

   - gh-92871(295): Remove the ‘typing.io’ and ‘typing.re’ namespaces,
     deprecated since Python 3.8.  All items are still available from
     the main *note typing: 104. module.

   - bpo-43633(296): Improve the textual representation of IPv4-mapped
     IPv6 addresses ( RFC 4291(297) Sections 2.2, 2.5.5.2) in *note
     ipaddress: 80.  Patch by Oleksandr Pavliuk.

   - bpo-44850(298): Improve performance of *note
     operator.methodcaller(): e67. using the PEP 590(299) ‘vectorcall’
     convention.  Patch by Anthony Lee and Pieter Eendebak.

   - bpo-44185(300): *note unittest.mock.mock_open(): 1022. will call
     the ‘close()’ method of the file handle mock when it is exiting
     from the context manager.  Patch by Samet Yaslan.

   - bpo-40988(301): Improve performance of *note
     functools.singledispatchmethod: 9fb. by caching the generated
     dispatch wrapper.  Optimization suggested by frederico.  Patch by
     @mental32, Alex Waygood and Pieter Eendebak.

   - bpo-41768(302): *note unittest.mock: 107. speccing no longer calls
     class properties.  Patch by Melanie Witt.

   - bpo-18319(303): Ensure ‘gettext(msg)’ retrieve translations even if
     a plural form exists.  In other words: ‘gettext(msg) ==
     ngettext(msg, '', 1)’.

   - bpo-17013(304): Add ‘ThreadingMock’ to *note unittest.mock: 107.
     that can be used to create Mock objects that can wait until they
     are called.  Patch by Karthikeyan Singaravelan and Mario Corchero.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/110786

   (2) https://github.com/python/cpython/issues/103480

   (3) https://github.com/python/cpython/issues/110733

   (4) https://github.com/python/cpython/issues/94597

   (5) https://github.com/python/cpython/issues/110682

   (6) https://github.com/python/cpython/issues/110488

   (7) https://github.com/python/cpython/issues/110590

   (8) https://github.com/python/cpython/issues/65052

   (9) https://github.com/python/cpython/issues/110519

   (10) https://github.com/python/cpython/issues/89902

   (11) https://github.com/python/cpython/issues/110378

   (12) https://github.com/python/cpython/issues/106670

   (13) https://github.com/python/cpython/issues/110365

   (14) https://github.com/python/cpython/issues/109653

   (15) https://github.com/python/cpython/issues/110273

   (16) https://github.com/python/cpython/issues/110249

   (17) https://github.com/python/cpython/issues/109653

   (18) https://github.com/python/cpython/issues/110222

   (19) https://github.com/python/cpython/issues/109649

   (20) https://github.com/python/cpython/issues/110150

   (21) https://github.com/python/cpython/issues/110036

   (22) https://github.com/python/cpython/issues/110038

   (23) https://github.com/python/cpython/issues/110045

   (24) https://peps.python.org/pep-0695/

   (25) https://github.com/python/cpython/issues/88402

   (26) https://github.com/python/cpython/issues/109631

   (27) https://github.com/python/cpython/issues/109653

   (28) https://github.com/python/cpython/issues/109818

   (29) https://github.com/python/cpython/issues/109047

   (30) https://github.com/python/cpython/issues/109782

   (31) https://github.com/python/cpython/issues/109653

   (32) https://github.com/python/cpython/issues/109590

   (33) https://github.com/python/cpython/issues/109653

   (34) https://github.com/python/cpython/issues/109593

   (35) https://github.com/python/cpython/issues/109653

   (36) https://github.com/python/cpython/issues/109649

   (37) https://github.com/python/cpython/issues/74481

   (38) https://github.com/python/cpython/issues/109613

   (39) https://github.com/python/cpython/issues/109599

   (40) https://github.com/python/cpython/issues/109109

   (41) https://github.com/python/cpython/issues/109559

   (42) https://github.com/python/cpython/issues/109543

   (43) https://github.com/python/cpython/issues/109495

   (44) https://github.com/python/cpython/issues/109461

   (45) https://github.com/python/cpython/issues/109096

   (46) https://github.com/python/cpython/issues/109409

   (47) https://github.com/python/cpython/issues/109375

   (48) https://github.com/python/cpython/issues/109319

   (49) https://github.com/python/cpython/issues/107219

   (50) https://github.com/python/cpython/issues/66143

   (51) https://github.com/python/cpython/issues/109187

   (52) https://github.com/python/cpython/issues/50644

   (53) https://github.com/python/cpython/issues/109174

   (54) https://github.com/python/cpython/issues/109164

   (55) https://github.com/python/cpython/issues/109151

   (56) https://github.com/python/cpython/issues/108987

   (57) https://github.com/python/cpython/issues/108682

   (58) https://github.com/python/cpython/issues/109033

   (59) https://github.com/python/cpython/issues/108843

   (60) https://github.com/python/cpython/issues/108469

   (61) https://github.com/python/cpython/issues/108751

   (62) https://github.com/python/cpython/issues/108682

   (63) https://github.com/python/cpython/issues/108278

   (64) https://github.com/python/cpython/issues/105829

   (65) https://github.com/python/cpython/issues/108295

   (66) https://github.com/python/cpython/issues/108463

   (67) https://github.com/python/cpython/issues/108277

   (68) https://github.com/python/cpython/issues/107811

   (69) https://github.com/python/cpython/issues/64662

   (70) https://github.com/python/cpython/issues/108111

   (71) https://github.com/python/cpython/issues/101251

   (72) https://github.com/python/cpython/issues/108294

   (73) https://github.com/python/cpython/issues/108278

   (74) https://github.com/python/cpython/issues/108322

   (75) https://github.com/python/cpython/issues/83417

   (76) https://github.com/python/cpython/issues/105736

   (77) https://github.com/python/cpython/issues/108083

   (78) https://github.com/python/cpython/issues/107932

   (79) https://github.com/python/cpython/issues/105539

   (80) https://github.com/python/cpython/issues/107995

   (81) https://github.com/python/cpython/issues/107963

   (82) https://github.com/python/cpython/issues/106242

   (83) https://github.com/python/cpython/issues/81555

   (84) https://github.com/python/cpython/issues/50002

   (85) https://github.com/python/cpython/issues/93057

   (86) https://github.com/python/cpython/issues/76913

   (87) https://github.com/python/cpython/issues/107913

   (88) https://github.com/python/cpython/issues/107845

   (89) https://github.com/python/cpython/issues/107812

   (90) https://github.com/python/cpython/issues/107805

   (91) https://github.com/python/cpython/issues/107782

   (92) https://github.com/python/cpython/issues/56166

   (93) https://github.com/python/cpython/issues/107710

   (94) https://github.com/python/cpython/issues/107715

   (95) https://github.com/python/cpython/issues/100814

   (96) https://github.com/python/cpython/issues/72684

   (97) https://github.com/python/cpython/issues/106684

   (98) https://github.com/python/cpython/issues/107465

   (99) https://github.com/python/cpython/issues/107077

   (100) https://github.com/python/cpython/issues/107576

   (101) https://github.com/python/cpython/issues/105481

   (102) https://github.com/python/cpython/issues/105481

   (103) https://github.com/python/cpython/issues/107396

   (104) https://github.com/python/cpython/issues/107409

   (105) https://github.com/python/cpython/issues/107406

   (106) https://github.com/python/cpython/issues/107369

   (107) https://github.com/python/cpython/issues/78722

   (108) https://github.com/python/cpython/issues/105578

   (109) https://github.com/python/cpython/issues/62519

   (110) https://github.com/python/cpython/issues/107089

   (111) https://github.com/python/cpython/issues/82500

   (112) https://github.com/python/cpython/issues/83006

   (113) https://github.com/python/cpython/issues/65495

   (114) https://github.com/python/cpython/issues/106186

   (115) https://github.com/python/cpython/issues/105002

   (116) https://github.com/python/cpython/issues/106739

   (117) https://github.com/python/cpython/issues/106751

   (118) https://github.com/python/cpython/issues/106751

   (119) https://github.com/python/cpython/issues/106751

   (120) https://github.com/python/cpython/issues/106831

   (121) https://github.com/python/cpython/issues/105481

   (122) https://github.com/python/cpython/issues/106727

   (123) https://github.com/python/cpython/issues/106789

   (124) https://github.com/python/cpython/issues/105726

   (125) https://github.com/python/cpython/issues/106774

   (126) https://github.com/python/cpython/issues/106751

   (127) https://github.com/python/cpython/issues/106752

   (128) https://github.com/python/cpython/issues/105293

   (129) https://github.com/python/cpython/issues/106734

   (130) https://github.com/python/cpython/issues/105481

   (131) https://github.com/python/cpython/issues/106670

   (132) https://github.com/python/cpython/issues/106602

   (133) https://github.com/python/cpython/issues/106664

   (134) https://github.com/python/cpython/issues/106628

   (135) https://github.com/python/cpython/issues/89427

   (136) https://github.com/python/cpython/issues/106530

   (137) https://github.com/python/cpython/issues/106584

   (138) https://github.com/python/cpython/issues/106566

   (139) https://github.com/python/cpython/issues/106554

   (140) https://github.com/python/cpython/issues/106558

   (141) https://github.com/python/cpython/issues/100502

   (142) https://github.com/python/cpython/issues/106527

   (143) https://github.com/python/cpython/issues/106524

   (144) https://github.com/python/cpython/issues/106531

   (145) https://github.com/python/cpython/issues/106052

   (146) https://github.com/python/cpython/issues/106510

   (147) https://github.com/python/cpython/issues/106503

   (148) https://github.com/python/cpython/issues/105497

   (149) https://github.com/python/cpython/issues/90876

   (150) https://github.com/python/cpython/issues/106403

   (151) https://github.com/python/cpython/issues/89812

   (152) https://github.com/python/cpython/issues/106292

   (153) https://github.com/python/cpython/issues/106350

   (154) https://github.com/python/cpython/issues/106330

   (155) https://github.com/python/cpython/issues/106309

   (156) https://github.com/python/cpython/issues/102541

   (157) https://github.com/python/cpython/issues/106263

   (158) https://github.com/python/cpython/issues/106236

   (159) https://github.com/python/cpython/issues/106238

   (160) https://github.com/python/cpython/issues/106152

   (161) https://github.com/python/cpython/issues/106075

   (162) https://github.com/python/cpython/issues/104527

   (163) https://github.com/python/cpython/issues/106046

   (164) https://github.com/python/cpython/issues/105987

   (165) https://github.com/python/cpython/issues/105974

   (166) https://github.com/python/cpython/issues/96145

   (167) https://github.com/python/cpython/issues/89812

   (168) https://github.com/python/cpython/issues/105808

   (169) https://github.com/python/cpython/issues/101251

   (170) https://github.com/python/cpython/issues/105481

   (171) https://github.com/python/cpython/issues/104799

   (172) https://peps.python.org/pep-0695/

   (173) https://github.com/python/cpython/issues/105793

   (174) https://github.com/python/cpython/issues/105570

   (175) https://github.com/python/cpython/issues/105745

   (176) https://github.com/python/cpython/issues/105733

   (177) https://github.com/python/cpython/issues/105687

   (178) https://github.com/python/cpython/issues/105684

   (179) https://github.com/python/cpython/issues/105375

   (180) https://github.com/python/cpython/issues/105626

   (181) https://github.com/python/cpython/issues/105375

   (182) https://github.com/python/cpython/issues/105605

   (183) https://github.com/python/cpython/issues/105375

   (184) https://github.com/python/cpython/issues/105375

   (185) https://github.com/python/cpython/issues/105375

   (186) https://github.com/python/cpython/issues/105375

   (187) https://github.com/python/cpython/issues/105375

   (188) https://github.com/python/cpython/issues/105375

   (189) https://github.com/python/cpython/issues/105375

   (190) https://github.com/python/cpython/issues/105375

   (191) https://github.com/python/cpython/issues/105375

   (192) https://github.com/python/cpython/issues/105566

   (193) https://github.com/python/cpython/issues/105545

   (194) https://github.com/python/cpython/issues/105497

   (195) https://github.com/python/cpython/issues/105509

   (196) https://github.com/python/cpython/issues/105375

   (197) https://github.com/python/cpython/issues/70303

   (198) https://github.com/python/cpython/issues/105375

   (199) https://github.com/python/cpython/issues/105382

   (200) https://github.com/python/cpython/issues/105376

   (201) https://github.com/python/cpython/issues/105332

   (202) https://github.com/python/cpython/issues/104554

   (203) https://github.com/python/cpython/issues/105292

   (204) https://github.com/python/cpython/issues/105280

   (205) https://github.com/python/cpython/issues/80480

   (206) https://github.com/python/cpython/issues/105239

   (207) https://github.com/python/cpython/issues/104310

   (208) https://github.com/python/cpython/issues/105080

   (209) https://github.com/python/cpython/issues/105144

   (210) https://github.com/python/cpython/issues/62948

   (211) https://github.com/python/cpython/issues/105096

   (212) https://github.com/python/cpython/issues/104992

   (213) https://github.com/python/cpython/issues/104996

   (214) https://github.com/python/cpython/issues/101588

   (215) https://github.com/python/cpython/issues/103631

   (216) https://github.com/python/cpython/issues/104947

   (217) https://github.com/python/cpython/issues/104773

   (218) https://peps.python.org/pep-0594/

   (219) https://github.com/python/cpython/issues/104773

   (220) https://peps.python.org/pep-0594/

   (221) https://github.com/python/cpython/issues/104773

   (222) https://peps.python.org/pep-0594/

   (223) https://github.com/python/cpython/issues/104935

   (224) https://peps.python.org/pep-0695/

   (225) https://github.com/python/cpython/issues/104773

   (226) https://peps.python.org/pep-0594/

   (227) https://github.com/python/cpython/issues/104773

   (228) https://peps.python.org/pep-0594/

   (229) https://github.com/python/cpython/issues/104898

   (230) https://github.com/python/cpython/issues/104773

   (231) https://peps.python.org/pep-0594/

   (232) https://github.com/python/cpython/issues/104773

   (233) https://peps.python.org/pep-0594/

   (234) https://github.com/python/cpython/issues/104886

   (235) https://github.com/python/cpython/issues/104786

   (236) https://github.com/python/cpython/issues/104876

   (237) https://github.com/python/cpython/issues/104773

   (238) https://peps.python.org/pep-0594/

   (239) https://github.com/python/cpython/issues/104773

   (240) https://peps.python.org/pep-0594/

   (241) https://pypi.org/project/python-pam/

   (242) https://github.com/python/cpython/issues/75552

   (243) https://github.com/python/cpython/issues/104773

   (244) https://peps.python.org/pep-0594/

   (245) https://github.com/python/cpython/issues/104773

   (246) https://peps.python.org/pep-0594/

   (247) https://github.com/python/cpython/issues/104773

   (248) https://peps.python.org/pep-0594/

   (249) https://github.com/python/cpython/issues/104780

   (250) https://peps.python.org/pep-0594/

   (251) https://github.com/python/cpython/issues/104773

   (252) https://peps.python.org/pep-0594/

   (253) https://github.com/python/cpython/issues/104873

   (254) https://github.com/python/cpython/issues/104874

   (255) https://github.com/python/cpython/issues/104835

   (256) https://github.com/python/cpython/issues/104804

   (257) https://github.com/python/cpython/issues/83863

   (258) https://github.com/python/cpython/issues/104799

   (259) https://peps.python.org/pep-0695/

   (260) https://github.com/python/cpython/issues/104797

   (261) https://github.com/python/cpython/issues/104783

   (262) https://github.com/python/cpython/issues/104780

   (263) https://github.com/python/cpython/issues/104773

   (264) https://peps.python.org/pep-0594/

   (265) https://github.com/python/cpython/issues/104773

   (266) https://peps.python.org/pep-0594/

   (267) https://github.com/python/cpython/issues/104773

   (268) https://peps.python.org/pep-0594/

   (269) https://github.com/python/cpython/issues/104773

   (270) https://peps.python.org/pep-0594/

   (271) https://github.com/python/cpython/issues/104372

   (272) https://github.com/python/cpython/issues/99108

   (273) https://github.com/python/cpython/issues/102613

   (274) https://github.com/python/cpython/issues/104399

   (275) https://github.com/python/cpython/issues/102676

   (276) https://github.com/python/cpython/issues/103558

   (277) https://github.com/python/cpython/issues/103464

   (278) https://github.com/python/cpython/issues/103384

   (279) https://github.com/python/cpython/issues/103124

   (280) https://github.com/python/cpython/issues/101162

   (281) https://github.com/python/cpython/issues/103200

   (282) https://github.com/python/cpython/issues/100061

   (283) https://github.com/python/cpython/issues/77609

   (284) https://github.com/python/cpython/issues/102541

   (285) https://github.com/python/cpython/issues/102120

   (286) https://github.com/python/cpython/issues/102029

   (287) https://github.com/python/cpython/issues/88233

   (288) https://github.com/python/cpython/issues/102024

   (289) https://github.com/python/cpython/issues/73435

   (290) https://github.com/python/cpython/issues/84867

   (291) https://github.com/python/cpython/issues/99203

   (292) https://github.com/python/cpython/issues/80480

   (293) https://github.com/python/cpython/issues/94924

   (294) https://github.com/python/cpython/issues/94777

   (295) https://github.com/python/cpython/issues/92871

   (296) https://bugs.python.org/issue?@action=redirect&bpo=43633

   (297) https://datatracker.ietf.org/doc/html/rfc4291.html

   (298) https://bugs.python.org/issue?@action=redirect&bpo=44850

   (299) https://peps.python.org/pep-0590/

   (300) https://bugs.python.org/issue?@action=redirect&bpo=44185

   (301) https://bugs.python.org/issue?@action=redirect&bpo=40988

   (302) https://bugs.python.org/issue?@action=redirect&bpo=41768

   (303) https://bugs.python.org/issue?@action=redirect&bpo=18319

   (304) https://bugs.python.org/issue?@action=redirect&bpo=17013


File: python.info,  Node: Documentation<18>,  Next: Tests<21>,  Prev: Library<39>,  Up: Python 3 13 0 alpha 1

1.23.27.4 Documentation
.......................

   - gh-109209(1): The minimum Sphinx version required for the
     documentation is now 4.2.

   - gh-108826(2): *note dis: 38. module command-line interface is now
     mentioned in documentation.

   - gh-107305(3): Add documentation for *note PyInterpreterConfig: 570.
     and *note Py_NewInterpreterFromConfig(): 45f.  Also clarify some of
     the nearby docs relative to per-interpreter GIL.

   - gh-107008(4): Document the *note curses: 2b. module variables *note
     LINES: e1d. and *note COLS: e1e.

   - gh-106948(5): Add a number of standard external names to
     ‘nitpick_ignore’.

   - gh-106232(6): Make timeit doc command lines compatible with Windows
     by using double quotes for arguments.  This works on linux and
     macOS also.

   - gh-105172(7): Fixed *note functools.lru_cache(): 9fa. docstring
     accounting for ‘typed’ argument’s different handling of str and
     int.  Patch by Bar Harel.

   - gh-105052(8): Update ‘timeit’ doc to specify that time in seconds
     is just the default.

   - gh-89455(9): Add missing documentation for the ‘max_group_depth’
     and ‘max_group_width’ parameters and the ‘exceptions’ attribute of
     the *note traceback.TracebackException: 25c. class.

   - gh-89412(10): Add missing documentation for the ‘end_lineno’ and
     ‘end_offset’ attributes of the *note traceback.TracebackException:
     25c. class.

   - gh-104943(11): Remove mentions of old Python versions in *note
     typing.NamedTuple: 2b0.

   - gh-54738(12): Add documentation on how to localize the *note
     argparse: 6. module.

   - gh-102823(13): Document the return type of ‘x // y’ when ‘x’ and
     ‘y’ have type *note float: 2f7.

   - gh-102759(14): Align function signature for ‘functools.reduce’ in
     documentation and docstring with the C implementation.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109209

   (2) https://github.com/python/cpython/issues/108826

   (3) https://github.com/python/cpython/issues/107305

   (4) https://github.com/python/cpython/issues/107008

   (5) https://github.com/python/cpython/issues/106948

   (6) https://github.com/python/cpython/issues/106232

   (7) https://github.com/python/cpython/issues/105172

   (8) https://github.com/python/cpython/issues/105052

   (9) https://github.com/python/cpython/issues/89455

   (10) https://github.com/python/cpython/issues/89412

   (11) https://github.com/python/cpython/issues/104943

   (12) https://github.com/python/cpython/issues/54738

   (13) https://github.com/python/cpython/issues/102823

   (14) https://github.com/python/cpython/issues/102759


File: python.info,  Node: Tests<21>,  Next: Build<21>,  Prev: Documentation<18>,  Up: Python 3 13 0 alpha 1

1.23.27.5 Tests
...............

   - gh-110647(1): Fix test_stress_modifying_handlers() of test_signal.
     Patch by Victor Stinner.

   - gh-103053(2): Fix test_tools.test_freeze on FreeBSD: run “make
     distclean” instead of “make clean” in the copied source directory
     to remove also the “python” program.  Patch by Victor Stinner.

   - gh-110167(3): Fix a deadlock in test_socket when server fails with
     a timeout but the client is still running in its thread.  Don’t
     hold a lock to call cleanup functions in doCleanups().  One of the
     cleanup function waits until the client completes, whereas the
     client could deadlock if it called addCleanup() in such situation.
     Patch by Victor Stinner.

   - gh-110388(4): Add tests for *note tty: 100.

   - gh-81002(5): Add tests for *note termios: e1.

   - gh-110367(6): regrtest: When using worker processes (-jN) with
     –verbose3 option, regrtest can now display the worker output even
     if a worker process does crash.  Previously, sys.stdout and
     sys.stderr were replaced and so the worker output was lost on a
     crash.  Patch by Victor Stinner.

   - gh-110267(7): Add tests for pickling and copying PyStructSequence
     objects.  Patched by Xuehai Pan.

   - gh-110171(8): ‘libregrtest’ now always sets and shows
     ‘random.seed’, so tests are more reproducible.  Use ‘--randseed’
     flag to pass the explicit random seed for tests.

   - gh-110152(9): Remove ‘Tools/scripts/run_tests.py’ and ‘make
     hostrunnertest’.  Just run ‘./python -m test --slow-ci’, ‘make
     buildbottest’ or ‘make test’ instead.  Python test runner
     (regrtest) now handles cross-compilation and HOSTRUNNER. It also
     adds options to Python such fast ‘-u -E -W default -bb’ when
     ‘--fast-ci’ or ‘--slow-ci’ option is used.  Patch by Victor
     Stinner.

   - gh-110031(10): Skip test_threading tests using thread+fork if
     Python is built with Address Sanitizer (ASAN). Patch by Victor
     Stinner.

   - gh-110088(11): Fix test_asyncio timeouts: don’t measure the maximum
     duration, a test should not measure a CI performance.  Only measure
     the minimum duration when a task has a timeout or delay.  Add
     ‘CLOCK_RES’ to ‘test_asyncio.utils’.  Patch by Victor Stinner.

   - gh-109974(12): Fix race conditions in test_threading lock tests.
     Wait until a condition is met rather than using *note time.sleep():
     6a0. with a hardcoded number of seconds.  Patch by Victor Stinner.

   - gh-110033(13): Fix ‘test_interprocess_signal()’ of ‘test_signal’.
     Make sure that the ‘subprocess.Popen’ object is deleted before the
     test raising an exception in a signal handler.  Otherwise,
     ‘Popen.__del__()’ can get the exception which is logged as
     ‘Exception ignored in: ...’ and the test fails.  Patch by Victor
     Stinner.

   - gh-109594(14): Fix test_timeout() of
     test_concurrent_futures.test_wait.  Remove the future which may or
     may not complete depending if it takes longer than the timeout or
     not.  Keep the second future which does not complete before wait()
     timeout.  Patch by Victor Stinner.

   - gh-109972(15): Split test_gdb.py file into a test_gdb package made
     of multiple tests, so tests can now be run in parallel.  Patch by
     Victor Stinner.

   - gh-109566(16): regrtest: When ‘--fast-ci’ or ‘--slow-ci’ option is
     used, regrtest now replaces the current process with a new process
     to add ‘-u -W default -bb -E’ options to Python.  Patch by Victor
     Stinner.

   - gh-109748(17): Fix ‘test_zippath_from_non_installed_posix()’ of
     test_venv: don’t copy ‘__pycache__/’ sub-directories, because they
     can be modified by other Python tests running in parallel.  Patch
     by Victor Stinner.

   - gh-109739(18): regrtest: Fix reference leak check on Windows.
     Disable the load tracker on Windows in the reference leak check
     mode (-R option).  Patch by Victor Stinner.

   - gh-109276(19): regrtest: When a test fails with “env changed” and
     the –rerun option is used, the test is now re-run in verbose mode
     in a fresh process.  Patch by Victor Stinner.

   - gh-103053(20): Skip test_freeze_simple_script() of
     test_tools.test_freeze if Python is built with ‘./configure
     --enable-optimizations’, which means with Profile Guided
     Optimization (PGO): it just makes the test too slow.  The freeze
     tool is tested by many other CIs with other (faster) compiler
     flags.  Patch by Victor Stinner.

   - gh-109580(21): Skip ‘test_perf_profiler’ if Python is built with
     ASAN, MSAN or UBSAN sanitizer.  Python does crash randomly in this
     test on such build.  Patch by Victor Stinner.

   - gh-109566(22): regrtest: Add ‘--fast-ci’ and ‘--slow-ci’ options.
     ‘--fast-ci’ uses a default timeout of 10 minutes and ‘-u all,-cpu’
     (skip slowest tests).  ‘--slow-ci’ uses a default timeout of 20
     minutes and ‘-u all’ (run all tests).  Patch by Victor Stinner.

   - gh-109425(23): libregrtest now decodes stdout of test worker
     processes with the “backslashreplace” error handler to log
     corrupted stdout, instead of failing with an error and not logging
     the stdout.  Patch by Victor Stinner.

   - gh-109396(24): Fix ‘test_socket.test_hmac_sha1()’ in FIPS mode.
     Use a longer key: FIPS mode requires at least of at least 112 bits.
     The previous key was only 32 bits.  Patch by Victor Stinner.

   - gh-104736(25): Fix test_gdb on Python built with LLVM clang 16 on
     Linux ppc64le (ex: Fedora 38).  Search patterns in gdb “bt” command
     output to detect when gdb fails to retrieve the traceback.  For
     example, skip a test if ‘Backtrace stopped: frame did not save the
     PC’ is found.  Patch by Victor Stinner.

   - gh-109276(26): libregrtest now calls *note random.seed(): 12ba.
     before running each test file when ‘-r/--randomize’ command line
     option is used.  Moreover, it’s also called in worker processes.
     It should help to make tests more deterministic.  Previously, it
     was only called once in the main process before running all test
     files and it was not called in worker processes.  Patch by Victor
     Stinner.

   - gh-109276(27): libregrtest now uses a separated file descriptor to
     write test result as JSON. Previously, if a test wrote debug
     messages late around the JSON, the main test process failed to
     parse JSON. Patch by Victor Stinner.

   - gh-108996(28): Fix and enable ‘test_msvcrt’.

   - gh-109237(29): Fix ‘test_site.test_underpth_basic()’ when the
     working directory contains at least one non-ASCII character: encode
     the ‘._pth’ file to UTF-8 and enable the UTF-8 Mode to use UTF-8
     for the child process stdout.  Patch by Victor Stinner.

   - gh-109230(30): Fix ‘test_pyexpat.test_exception()’: it can now be
     run from a directory different than Python source code directory.
     Before, the test failed in this case.  Skip the test if
     Modules/pyexpat.c source is not available.  Skip also the test on
     Python implementations other than CPython.  Patch by Victor
     Stinner.

   - gh-108996(31): Add tests for ‘msvcrt’.

   - gh-109015(32): Fix test_asyncio, test_imaplib and test_socket tests
     on FreeBSD if the TCP blackhole is enabled (‘sysctl
     net.inet.tcp.blackhole’).  Skip the few tests which failed with
     ‘ETIMEDOUT’ which such non standard configuration.  Currently, the
     FreeBSD GCP image enables TCP and UDP blackhole(33) (‘sysctl
     net.inet.tcp.blackhole=2’ and ‘sysctl net.inet.udp.blackhole=1’).
     Patch by Victor Stinner.

   - gh-91960(34): Skip ‘test_gdb’ if gdb is unable to retrieve Python
     frame objects: if a frame is ‘<optimized out>’.  When Python is
     built with “clang -Og”, gdb can fail to retrieve the 'frame'
     parameter of ‘_PyEval_EvalFrameDefault()’.  In this case, tests
     like ‘py_bt()’ are likely to fail.  Without getting access to
     Python frames, ‘python-gdb.py’ is mostly clueless on retrieving the
     Python traceback.  Moreover, ‘test_gdb’ is no longer skipped on
     macOS if Python is built with Clang.  Patch by Victor Stinner.

   - gh-108962(35): Skip ‘test_tempfile.test_flags()’ if ‘chflags()’
     fails with “OSError: [Errno 45] Operation not supported” (ex: on
     FreeBSD 13).  Patch by Victor Stinner.

   - gh-91960(36): FreeBSD 13.2 CI coverage for pull requests is now
     provided by Cirrus-CI (a hosted CI service that supports Linux,
     macOS, Windows, and FreeBSD).

   - gh-89392(37): Removed support of ‘test_main()’ function in tests.
     They now always use normal unittest test runner.

   - gh-108851(38): Fix ‘test_tomllib’ recursion tests for WASI
     buildbots: reduce the recursion limit and compute the maximum
     nested array/dict depending on the current available recursion
     limit.  Patch by Victor Stinner.

   - gh-108851(39): Add ‘get_recursion_available()’ and
     ‘get_recursion_depth()’ functions to the *note test.support: e4.
     module.  Patch by Victor Stinner.

   - gh-108834(40): Add ‘--fail-rerun option’ option to regrtest: if a
     test failed when then passed when rerun in verbose mode, exit the
     process with exit code 2 (error), instead of exit code 0 (success).
     Patch by Victor Stinner.

   - gh-108834(41): Rename regrtest ‘--verbose2’ option (‘-w’) to
     ‘--rerun’.  Keep ‘--verbose2’ as a deprecated alias.  Patch by
     Victor Stinner.

   - gh-108834(42): When regrtest reruns failed tests in verbose mode
     (‘./python -m test --rerun’), tests are now rerun in fresh worker
     processes rather than being executed in the main process.  If a
     test does crash or is killed by a timeout, the main process can
     detect and handle the killed worker process.  Tests are rerun in
     parallel if the ‘-jN’ option is used to run tests in parallel.
     Patch by Victor Stinner.

   - gh-108822(43): ‘regrtest’ now computes statistics on all tests:
     successes, failures and skipped.  ‘test_netrc’,
     ‘test_pep646_syntax’ and ‘test_xml_etree’ now return results in
     their ‘test_main()’ function.  Patch by Victor Stinner and Alex
     Waygood.

   - gh-108794(44): The *note doctest.DocTestRunner.run(): 1dc. method
     now counts the number of skipped tests.  Add *note
     doctest.DocTestRunner.skips: 1dd. and *note
     doctest.TestResults.skipped: 1de. attributes.  Patch by Victor
     Stinner.

   - gh-108388(45): Convert test_concurrent_futures to a package of 7
     sub-tests.  Patch by Victor Stinner.

   - gh-108388(46): Split test_multiprocessing_fork,
     test_multiprocessing_forkserver and test_multiprocessing_spawn into
     test packages.  Each package is made of 4 sub-tests: processes,
     threads, manager and misc.  It allows running more tests in
     parallel and so reduce the total test duration.  Patch by Victor
     Stinner.

   - gh-105776(47): Fix test_cppext when the C compiler command
     ‘-std=c11’ option: remove ‘-std=’ options from the compiler
     command.  Patch by Victor Stinner.

   - gh-107652(48): Set up CIFuzz to run fuzz targets in GitHub Actions.
     Patch by Illia Volochii.

   - gh-107237(49): ‘test_logging’: Fix ‘test_udp_reconnection()’ by
     increasing the timeout from 100 ms to 5 minutes (LONG_TIMEOUT).
     Patch by Victor Stinner.

   - gh-107178(50): Add the C API test for functions in the Mapping
     Protocol, the Sequence Protocol and some functions in the Object
     Protocol.

   - gh-106714(51): test_capi: Fix test_no_FatalError_infinite_loop() to
     no longer write a coredump, by using
     test.support.SuppressCrashReport.  Patch by Victor Stinner.

   - gh-104090(52): Avoid creating a reference to the test object in
     *note collectedDurations(): 181b.

   - gh-106752(53): Moved tests for ‘zipfile.Path’ into
     ‘Lib/test/test_zipfile/_path’.  Made ‘zipfile._path’ a package.

   - gh-106690(54): Add .coveragerc to cpython repository for use with
     coverage package.

   - gh-101634(55): When running the Python test suite with ‘-jN’
     option, if a worker stdout cannot be decoded from the locale
     encoding report a failed testn so the exitcode is non-zero.  Patch
     by Victor Stinner.

   - gh-105084(56): When the Python build is configured
     ‘--with-wheel-pkg-dir’, tests requiring the ‘setuptools’ and
     ‘wheel’ wheels will search for the wheels in ‘WHEEL_PKG_DIR’.

   - gh-81005(57): String tests are modified to reflect that ‘str’ and
     ‘unicode’ are merged in Python 3.  Patch by Daniel Fortunov.

   - gh-103186(58): Suppress and assert expected RuntimeWarnings in
     test_sys_settrace.py

   - gh-69714(59): Add additional tests to *note calendar: 14. to
     achieve full test coverage.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/110647

   (2) https://github.com/python/cpython/issues/103053

   (3) https://github.com/python/cpython/issues/110167

   (4) https://github.com/python/cpython/issues/110388

   (5) https://github.com/python/cpython/issues/81002

   (6) https://github.com/python/cpython/issues/110367

   (7) https://github.com/python/cpython/issues/110267

   (8) https://github.com/python/cpython/issues/110171

   (9) https://github.com/python/cpython/issues/110152

   (10) https://github.com/python/cpython/issues/110031

   (11) https://github.com/python/cpython/issues/110088

   (12) https://github.com/python/cpython/issues/109974

   (13) https://github.com/python/cpython/issues/110033

   (14) https://github.com/python/cpython/issues/109594

   (15) https://github.com/python/cpython/issues/109972

   (16) https://github.com/python/cpython/issues/109566

   (17) https://github.com/python/cpython/issues/109748

   (18) https://github.com/python/cpython/issues/109739

   (19) https://github.com/python/cpython/issues/109276

   (20) https://github.com/python/cpython/issues/103053

   (21) https://github.com/python/cpython/issues/109580

   (22) https://github.com/python/cpython/issues/109566

   (23) https://github.com/python/cpython/issues/109425

   (24) https://github.com/python/cpython/issues/109396

   (25) https://github.com/python/cpython/issues/104736

   (26) https://github.com/python/cpython/issues/109276

   (27) https://github.com/python/cpython/issues/109276

   (28) https://github.com/python/cpython/issues/108996

   (29) https://github.com/python/cpython/issues/109237

   (30) https://github.com/python/cpython/issues/109230

   (31) https://github.com/python/cpython/issues/108996

   (32) https://github.com/python/cpython/issues/109015

   (33) https://reviews.freebsd.org/D41751

   (34) https://github.com/python/cpython/issues/91960

   (35) https://github.com/python/cpython/issues/108962

   (36) https://github.com/python/cpython/issues/91960

   (37) https://github.com/python/cpython/issues/89392

   (38) https://github.com/python/cpython/issues/108851

   (39) https://github.com/python/cpython/issues/108851

   (40) https://github.com/python/cpython/issues/108834

   (41) https://github.com/python/cpython/issues/108834

   (42) https://github.com/python/cpython/issues/108834

   (43) https://github.com/python/cpython/issues/108822

   (44) https://github.com/python/cpython/issues/108794

   (45) https://github.com/python/cpython/issues/108388

   (46) https://github.com/python/cpython/issues/108388

   (47) https://github.com/python/cpython/issues/105776

   (48) https://github.com/python/cpython/issues/107652

   (49) https://github.com/python/cpython/issues/107237

   (50) https://github.com/python/cpython/issues/107178

   (51) https://github.com/python/cpython/issues/106714

   (52) https://github.com/python/cpython/issues/104090

   (53) https://github.com/python/cpython/issues/106752

   (54) https://github.com/python/cpython/issues/106690

   (55) https://github.com/python/cpython/issues/101634

   (56) https://github.com/python/cpython/issues/105084

   (57) https://github.com/python/cpython/issues/81005

   (58) https://github.com/python/cpython/issues/103186

   (59) https://github.com/python/cpython/issues/69714


File: python.info,  Node: Build<21>,  Next: Windows<19>,  Prev: Tests<21>,  Up: Python 3 13 0 alpha 1

1.23.27.6 Build
...............

   - gh-103053(1): “make check-clean-src” now also checks if the
     “python” program is found in the source directory: fail with an
     error if it does exist.  Patch by Victor Stinner.

   - gh-109191(2): Fix compile error when building with recent versions
     of libedit.

   - gh-110276(3): No longer ignore *note PROFILE_TASK: 181d. failure
     silently: command used by Profile Guided Optimization (PGO). Patch
     by Victor Stinner.

   - gh-109566(4): Remove ‘make testall’ target: use ‘make buildbottest’
     instead.  Patch by Victor Stinner.

   - gh-109740(5): The experimental ‘--disable-gil’ configure flag now
     includes “t” (for “threaded”) in extension ABI tags.

   - gh-109054(6): Fix building the ‘_testcapi’ extension on Linux
     AArch64 which requires linking to libatomic when
     ‘<cpython/pyatomic.h>’ is used: the ‘_Py_atomic_or_uint64()’
     function requires libatomic ‘__atomic_fetch_or_8()’ on this
     platform.  The configure script now checks if linking to libatomic
     is needed and generates a new LIBATOMIC variable used to build the
     _testcapi extension.  Patch by Victor Stinner.

   - gh-63760(7): Fix Solaris build: no longer redefine the
     ‘gethostname()’ function.  Solaris defines the function since 2005.
     Patch by Victor Stinner, original patch by Jakub Kulík.

   - gh-108740(8): Fix a race condition in ‘make regen-all’.  The
     ‘deepfreeze.c’ source and files generated by Argument Clinic are
     now generated or updated before generating “global objects”.
     Previously, some identifiers may miss depending on the order in
     which these files were generated.  Patch by Victor Stinner.

   - gh-108634(9): Python built with ‘configure’ *note -with-trace-refs:
     398. (tracing references) is now ABI compatible with Python release
     build and *note debug build: 1f9.  Patch by Victor Stinner.

   - gh-85283(10): The ‘_stat’ C extension is now built with the *note
     limited C API: 399.  Patch by Victor Stinner.

   - gh-108447(11): Fix x86_64 GNU/Hurd build

   - gh-107814(12): When calling ‘find_python.bat’ with ‘-q’ it did not
     properly silence the output of nuget.  That is now fixed.

   - gh-105481(13): Remove the make target ‘regen-opcode-targets’, merge
     its work into ‘regen-opcode’ which repeats most of the calculation.
     This simplifies the code for the build and reduces code
     duplication.

   - gh-106881(14): Check for ‘linux/limits.h’ before including it in
     ‘Modules/posixmodule.c’.

   - gh-95855(15): Refactor platform triplet detection code and add
     detection for MIPS soft float and musl libc.

   - gh-106962(16): Detect MPI compilers in ‘configure’.

   - gh-106118(17): Fix compilation for platforms without ‘O_CLOEXEC’.
     The issue was introduced with Python 3.12b1 in gh-103295(18).
     Patch by Erlend Aasland.

   - gh-105875(19): SQLite 3.15.2 or newer is required to build the
     *note sqlite3: cf. extension module.  Patch by Erlend Aasland.

   - gh-90005(20): Fix a regression in ‘configure’ where we could end up
     unintentionally linking with ‘libbsd’.

   - gh-102404(21): Document how to perform a WASI build on Linux.  Also
     add Tools/wasm/build_wasi.sh as a reference implementation of the
     docs.

   - gh-89886(22): Autoconf 2.71 and aclocal 1.16.4 is now required to
     regenerate ‘!configure’.

   - gh-104692(23): Include ‘commoninstall’ as a prerequisite for
     ‘bininstall’

     This ensures that ‘commoninstall’ is completed before ‘bininstall’
     is started when parallel builds are used (‘make -j install’), and
     so the ‘python3’ symlink is only installed after all standard
     library modules are installed.

   - gh-101538(24): Add experimental wasi-threads support.  Patch by
     Takashi Yamamoto.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103053

   (2) https://github.com/python/cpython/issues/109191

   (3) https://github.com/python/cpython/issues/110276

   (4) https://github.com/python/cpython/issues/109566

   (5) https://github.com/python/cpython/issues/109740

   (6) https://github.com/python/cpython/issues/109054

   (7) https://github.com/python/cpython/issues/63760

   (8) https://github.com/python/cpython/issues/108740

   (9) https://github.com/python/cpython/issues/108634

   (10) https://github.com/python/cpython/issues/85283

   (11) https://github.com/python/cpython/issues/108447

   (12) https://github.com/python/cpython/issues/107814

   (13) https://github.com/python/cpython/issues/105481

   (14) https://github.com/python/cpython/issues/106881

   (15) https://github.com/python/cpython/issues/95855

   (16) https://github.com/python/cpython/issues/106962

   (17) https://github.com/python/cpython/issues/106118

   (18) https://github.com/python/cpython/issues/103295

   (19) https://github.com/python/cpython/issues/105875

   (20) https://github.com/python/cpython/issues/90005

   (21) https://github.com/python/cpython/issues/102404

   (22) https://github.com/python/cpython/issues/89886

   (23) https://github.com/python/cpython/issues/104692

   (24) https://github.com/python/cpython/issues/101538


File: python.info,  Node: Windows<19>,  Next: macOS<14>,  Prev: Build<21>,  Up: Python 3 13 0 alpha 1

1.23.27.7 Windows
.................

   - gh-110437(1): Allows overriding the source of VC redistributables
     so that releases can be guaranteed to never downgrade between
     updates.

   - gh-109286(2): Update Windows installer to use SQLite 3.43.1.

   - gh-82367(3): *note os.path.realpath(): 225. now resolves MS-DOS
     style file names even if the file is not accessible.  Patch by
     Moonsik Park.

   - gh-109991(4): Update Windows build to use OpenSSL 3.0.11.

   - gh-106242(5): Fixes *note realpath(): 225. to behave consistently
     when passed a path containing an embedded null character on
     Windows.  In strict mode, it now raises *note OSError: 41a. instead
     of the unexpected *note ValueError: 202, and in non-strict mode
     will make the path absolute.

   - gh-83180(6): Changes the *note Python Launcher for Windows: 5c1. to
     prefer an active virtual environment when the launched script has a
     shebang line using a Unix-like virtual command, even if the command
     requests a specific version of Python.

   - gh-106844(7): Fix integer overflow and truncating by the null
     character in ‘_winapi.LCMapStringEx()’ which affects
     ‘ntpath.normcase()’.

   - gh-105436(8): Ensure that an empty environment block is terminated
     by two null characters, as is required by Windows.

   - gh-105146(9): Updated the links at the end of the installer to
     point to Discourse rather than the mailing lists.

   - gh-103646(10): When installed from the Microsoft Store, ‘pip’ no
     longer defaults to per-user installs.  However, as the install
     directory is unwritable, it should automatically decide to do a
     per-user install anyway.  This should resolve issues when ‘pip’ is
     passed an option that conflicts with ‘--user’.

   - gh-88745(11): Improve performance of *note shutil.copy2(): a69. by
     using the operating system’s ‘CopyFile2’ function.  This may result
     in subtle changes to metadata copied along with some files,
     bringing them in line with normal OS behavior.

   - gh-104820(12): Fixes *note stat(): 4a3. and related functions on
     file systems that do not support file ID requests.  This includes
     FAT32 and exFAT.

   - gh-104803(13): Add *note os.path.isdevdrive(): 1756. to detect
     whether a path is on a Windows Dev Drive.  Returns ‘False’ on
     platforms that do not support Dev Drive, and is absent on
     non-Windows platforms.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/110437

   (2) https://github.com/python/cpython/issues/109286

   (3) https://github.com/python/cpython/issues/82367

   (4) https://github.com/python/cpython/issues/109991

   (5) https://github.com/python/cpython/issues/106242

   (6) https://github.com/python/cpython/issues/83180

   (7) https://github.com/python/cpython/issues/106844

   (8) https://github.com/python/cpython/issues/105436

   (9) https://github.com/python/cpython/issues/105146

   (10) https://github.com/python/cpython/issues/103646

   (11) https://github.com/python/cpython/issues/88745

   (12) https://github.com/python/cpython/issues/104820

   (13) https://github.com/python/cpython/issues/104803


File: python.info,  Node: macOS<14>,  Next: IDLE<17>,  Prev: Windows<19>,  Up: Python 3 13 0 alpha 1

1.23.27.8 macOS
...............

   - gh-109286(1): Update macOS installer to use SQLite 3.43.1.

   - gh-109991(2): Update macOS installer to use OpenSSL 3.0.11.

   - gh-99079(3): Update macOS installer to use OpenSSL 3.0.9.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109286

   (2) https://github.com/python/cpython/issues/109991

   (3) https://github.com/python/cpython/issues/99079


File: python.info,  Node: IDLE<17>,  Next: Tools/Demos<12>,  Prev: macOS<14>,  Up: Python 3 13 0 alpha 1

1.23.27.9 IDLE
..............

   - gh-104719(1): Remove IDLE’s modification of tokenize.tabsize and
     test other uses of tokenize data and methods.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104719


File: python.info,  Node: Tools/Demos<12>,  Next: C API<21>,  Prev: IDLE<17>,  Up: Python 3 13 0 alpha 1

1.23.27.10 Tools/Demos
......................

   - gh-109991(1): Update GitHub CI workflows to use OpenSSL 3.0.11 and
     multissltests to use 1.1.1w, 3.0.11, and 3.1.3.

   - gh-108494(2): Argument Clinic(3) now has a partial support of the
     *note Limited API: 399.: see documentation in the Python
     Developer's Guide(4) Patch by Victor Stinner.

   - gh-107704(5): It is now possible to deprecate passing keyword
     arguments for keyword-or-positional parameters with Argument
     Clinic, using the new ‘/ [from X.Y]’ syntax.  (To be read as
     '“positional-only from Python version X.Y”'.)  See documentation in
     the Python Developer's Guide(6) for more information.

   - gh-107880(7): Argument Clinic can now clone ‘__init__()’ and
     ‘__new__()’ methods.

   - gh-104683(8): Add ‘--exclude’ option to Argument Clinic CLI.

   - gh-95065(9): Argument Clinic now supports overriding automatically
     generated signature by using directive ‘@text_signature’.  See
     documentation in the Python Developer's Guide(10)

   - gh-107609(11): Fix duplicate module check in Argument Clinic.
     Previously, a duplicate definition would incorrectly be silently
     accepted.  Patch by Erlend E. Aasland.

   - gh-107467(12): The Argument Clinic command-line tool now prints to
     stderr instead of stdout on failure.

   - gh-106970(13): Fix bugs in the Argument Clinic ‘destination <name>
     clear’ command; the destination buffers would never be cleared, and
     the ‘destination’ directive parser would simply continue to the
     fault handler after processing the command.  Patch by Erlend E.
     Aasland.

   - gh-106706(14): Change bytecode syntax for families to remove
     redundant name matching pseudo syntax.

   - gh-106359(15): Argument Clinic now explicitly forbids “kwarg
     splats” in function calls used as annotations.

   - gh-103186(16): ‘freeze’ now fetches ‘CONFIG_ARGS’ from the original
     CPython instance the Makefile uses to call utility scripts.  Patch
     by Ijtaba Hussain.

   - gh-95065(17): It is now possible to deprecate passing parameters
     positionally with Argument Clinic, using the new ‘* [from X.Y]’
     syntax.  (To be read as '“keyword-only from Python version X.Y”'.)
     See documentation in the Python Developer's Guide(18) for more
     information.  Patch by Erlend E. Aasland with help from Alex
     Waygood, Nikita Sobolev, and Serhiy Storchaka.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/109991

   (2) https://github.com/python/cpython/issues/108494

   (3) https://devguide.python.org/development-tools/clinic/

   (4) 
https://devguide.python.org/development-tools/clinic/#clinic-howto-limited-capi

   (5) https://github.com/python/cpython/issues/107704

   (6) 
https://devguide.python.org/development-tools/clinic/#clinic-howto-deprecate-keyword

   (7) https://github.com/python/cpython/issues/107880

   (8) https://github.com/python/cpython/issues/104683

   (9) https://github.com/python/cpython/issues/95065

   (10) 
https://devguide.python.org/development-tools/clinic/#clinic-howto-override-signature

   (11) https://github.com/python/cpython/issues/107609

   (12) https://github.com/python/cpython/issues/107467

   (13) https://github.com/python/cpython/issues/106970

   (14) https://github.com/python/cpython/issues/106706

   (15) https://github.com/python/cpython/issues/106359

   (16) https://github.com/python/cpython/issues/103186

   (17) https://github.com/python/cpython/issues/95065

   (18) 
https://devguide.python.org/development-tools/clinic/#clinic-howto-deprecate-positional


File: python.info,  Node: C API<21>,  Prev: Tools/Demos<12>,  Up: Python 3 13 0 alpha 1

1.23.27.11 C API
................

   - gh-85283(1): If the *note Py_LIMITED_API: 421. macro is defined,
     ‘Py_BUILD_CORE’, ‘Py_BUILD_CORE_BUILTIN’ and ‘Py_BUILD_CORE_MODULE’
     macros are now undefined by ‘<Python.h>’.  Patch by Victor Stinner.

   - gh-110289(2): Add *note PyUnicode_EqualToUTF8AndSize(): 379. and
     *note PyUnicode_EqualToUTF8(): 37a. functions.

   - gh-110235(3): Raise *note TypeError: 2c3. for duplicate/unknown
     fields in ‘PyStructSequence’ constructor.  Patched by Xuehai Pan.

   - gh-110014(4): Remove undocumented ‘PY_TIMEOUT_MAX’ constant from
     the limited C API. Patch by Victor Stinner.

   - gh-109521(5): *note PyImport_GetImporter(): 1823. now sets
     RuntimeError if it fails to get *note sys.path_hooks: 105f. or
     *note sys.path_importer_cache: 5e7. or they are not list and dict
     correspondingly.  Previously it could return NULL without setting
     error in obscure cases, crash or raise SystemError if these
     attributes have wrong type.

   - gh-108724(6): Add *note PyMutex: 15b. internal-only lightweight
     locking API.

   - gh-85283(7): Add *note PySys_AuditTuple(): 371. function: similar
     to *note PySys_Audit(): 372, but pass event arguments as a Python
     *note tuple: 373. object.  Patch by Victor Stinner.

   - gh-108867(8): Add *note PyThreadState_GetUnchecked(): 374.
     function: similar to *note PyThreadState_Get(): 375, but don’t kill
     the process with a fatal error if it is NULL. The caller is
     responsible to check if the result is NULL. Previously, the
     function was private and known as ‘_PyThreadState_UncheckedGet()’.
     Patch by Victor Stinner.

   - gh-108765(9): ‘Python.h’ no longer includes the ‘<ctype.h>’
     standard header file.  If needed, it should now be included
     explicitly.  For example, it provides ‘isalpha()’ and ‘tolower()’
     functions which are locale dependent.  Python provides locale
     independent functions, like ‘Py_ISALPHA()’ and ‘Py_TOLOWER()’.
     Patch by Victor Stinner.

   - gh-108765(10): ‘Python.h’ no longer includes the ‘<unistd.h>’
     standard header file.  If needed, it should now be included
     explicitly.  For example, it provides the functions: ‘close()’,
     ‘getpagesize()’, ‘getpid()’ and ‘sysconf()’.  Patch by Victor
     Stinner.

   - gh-108765(11): ‘Python.h’ no longer includes the ‘<ieeefp.h>’
     standard header.  It was included for the ‘finite()’ function which
     is now provided by the ‘<math.h>’ header.  It should now be
     included explicitly if needed.  Remove also the ‘HAVE_IEEEFP_H’
     macro.  Patch by Victor Stinner.

   - gh-108765(12): ‘Python.h’ no longer includes these standard header
     files: ‘<time.h>’, ‘<sys/select.h>’ and ‘<sys/time.h>’.  If needed,
     they should now be included explicitly.  For example, ‘<time.h>’
     provides the ‘clock()’ and ‘gmtime()’ functions, ‘<sys/select.h>’
     provides the ‘select()’ function, and ‘<sys/time.h>’ provides the
     ‘futimes()’, ‘gettimeofday()’ and ‘setitimer()’ functions.  Patch
     by Victor Stinner.

   - gh-108511(13): Add functions *note PyObject_HasAttrWithError():
     37d, *note PyObject_HasAttrStringWithError(): 37f, *note
     PyMapping_HasKeyWithError(): 381. and *note
     PyMapping_HasKeyStringWithError(): 383.

   - gh-107073(14): Add *note PyObject_VisitManagedDict(): 36c. and
     *note PyObject_ClearManagedDict(): 36d. functions which must be
     called by the traverse and clear functions of a type using *note
     Py_TPFLAGS_MANAGED_DICT: 36e. flag.  Patch by Victor Stinner.

   - gh-108634(15): Python built with ‘configure’ *note
     -with-trace-refs: 398. (tracing references) now supports the *note
     Limited API: 399.  Patch by Victor Stinner.

   - gh-108014(16): Add *note PyLong_AsInt(): 362. function: similar to
     *note PyLong_AsLong(): 363, but store the result in a C int instead
     of a C long.  Previously, it was known as the private function
     ‘_PyLong_AsInt()’ (with an underscore prefix).  Patch by Victor
     Stinner.

   - gh-108314(17): Add *note PyDict_ContainsString(): 338. function:
     same as *note PyDict_Contains(): 339, but 'key' is specified as a
     const char* UTF-8 encoded bytes string, rather than a *note
     PyObject: 33a.*.  Patch by Victor Stinner.

   - gh-108337(18): Add atomic operations on additional data types in
     pyatomic.h.

   - gh-108014(19): Add *note Py_IsFinalizing(): 35b. function: check if
     the main Python interpreter is *note shutting down: 14e.  Patch by
     Victor Stinner.

   - gh-107916(20): C API functions *note
     PyErr_SetFromErrnoWithFilename(): 1824, *note
     PyErr_SetExcFromWindowsErrWithFilename(): 1825. and *note
     PyErr_SetFromWindowsErrWithFilename(): 1826. save now the error
     code before calling *note PyUnicode_DecodeFSDefault(): 1827.

   - gh-107915(21): Such C API functions as ‘PyErr_SetString()’,
     ‘PyErr_Format()’, ‘PyErr_SetFromErrnoWithFilename()’ and many
     others no longer crash or ignore errors if it failed to format the
     error message or decode the filename.  Instead, they keep a
     corresponding error.

   - gh-107810(22): Improve *note DeprecationWarning: 1a5. for uses of
     *note PyType_Spec: 1828. with metaclasses that have custom
     ‘tp_new’.

   - gh-107249(23): Implement the *note Py_UNUSED: 1829. macro for
     Windows MSVC compiler.  Patch by Victor Stinner.

   - gh-107226(24): *note PyModule_AddObjectRef(): 368. is now only
     available in the limited API version 3.10 or later.

   - gh-106320(25): Remove private ‘_PyUnicode_AsString()’ alias to
     *note PyUnicode_AsUTF8(): bda.  It was kept for backward
     compatibility with Python 3.0 - 3.2.  The ‘PyUnicode_AsUTF8()’ is
     available since Python 3.3.  The *note PyUnicode_AsUTF8String():
     11d2. function can be used to keep compatibility with Python 3.2
     and older.  Patch by Victor Stinner.

   - gh-106572(26): Convert *note PyObject_DelAttr(): 163f. and *note
     PyObject_DelAttrString(): 1640. macros to functions.  Patch by
     Victor Stinner.

   - gh-106307(27): Add *note PyMapping_GetOptionalItem(): 346.
     function.

   - gh-106521(28): Add *note PyObject_GetOptionalAttr(): 34a. and *note
     PyObject_GetOptionalAttrString(): 34b. functions.

   - gh-106320(29): Remove ‘_PyInterpreterState_Get()’ alias to *note
     PyInterpreterState_Get(): 3b0. which was kept for backward
     compatibility with Python 3.8.  Patch by Victor Stinner.

   - gh-106316(30): Remove ‘cpython/pytime.h’ header file: it only
     contained private functions.  Patch by Victor Stinner.

   - gh-106023(31): Remove private ‘_PyObject_FastCall()’ function: use
     ‘PyObject_Vectorcall()’ which is available since Python 3.8 ( PEP
     590(32)).  Patch by Victor Stinner.

   - gh-106168(33): If Python is built in *note debug mode: 1f9. or
     *note with assertions: 38f, *note PyTuple_SET_ITEM(): 390. and
     *note PyList_SET_ITEM(): 391. now check the index argument with an
     assertion.  If the assertion fails, make sure that the size is set
     before.  Patch by Victor Stinner.

   - gh-106084(34): Remove the old aliases to functions calling
     functions which were kept for backward compatibility with Python
     3.8 provisional API:

        * ‘_PyObject_CallMethodNoArgs()’: use
          ‘PyObject_CallMethodNoArgs()’

        * ‘_PyObject_CallMethodOneArg()’: use
          ‘PyObject_CallMethodOneArg()’

        * ‘_PyObject_CallOneArg()’: use ‘PyObject_CallOneArg()’

        * ‘_PyObject_FastCallDict()’: use ‘PyObject_VectorcallDict()’

        * ‘_PyObject_Vectorcall()’: use ‘PyObject_Vectorcall()’

        * ‘_PyObject_VectorcallMethod()’: use
          ‘PyObject_VectorcallMethod()’

        * ‘_PyVectorcall_Function()’: use ‘PyVectorcall_Function()’

     Just remove the underscore prefix to update your code.  Patch by
     Victor Stinner.

   - gh-106004(35): Adds *note PyDict_GetItemRef(): 33b. and *note
     PyDict_GetItemStringRef(): 33c. functions: similar to *note
     PyDict_GetItemWithError(): 33d. but returning a *note strong
     reference: 33e. instead of a *note borrowed reference: 33f.  Patch
     by Victor Stinner.

   - gh-105927(36): Deprecate the *note PyWeakref_GetObject(): 37c. and
     *note PyWeakref_GET_OBJECT(): 3c2. functions: use the new *note
     PyWeakref_GetRef(): 37b. function instead.  Patch by Victor
     Stinner.

   - gh-105927(37): Add *note PyWeakref_GetRef(): 37b. function: similar
     to *note PyWeakref_GetObject(): 37c. but returns a *note strong
     reference: 33e, or ‘NULL’ if the referent is no longer live.  Patch
     by Victor Stinner.

   - gh-105922(38): Add *note PyImport_AddModuleRef(): 359.: similar to
     *note PyImport_AddModule(): 35a, but return a *note strong
     reference: 33e. instead of a *note borrowed reference: 33f.  Patch
     by Victor Stinner.

   - gh-105227(39): The new *note PyType_GetDict(): 182a. provides the
     dictionary for the given type object that is normally exposed by
     ‘cls.__dict__’.  Normally it’s sufficient to use *note tp_dict:
     182b, but for the static builtin types ‘tp_dict’ is now always
     ‘NULL’.  ‘PyType_GetDict()’ provides the correct dict object
     instead.

   - gh-105375(40): Fix a bug in *note PyErr_WarnExplicit(): 182c. where
     an exception could end up being overwritten if the API failed
     internally.

   - gh-105603(41): We’ve renamed the new (in 3.12)
     ‘PyInterpreterConfig.own_gil’ to ‘PyInterpreterConfig.gil’ and
     changed the meaning of the value from “bool” to an integer with
     supported values of ‘PyInterpreterConfig_DEFAULT_GIL’,
     ‘PyInterpreterConfig_SHARED_GIL’, and
     ‘PyInterpreterConfig_OWN_GIL’.  The default is “shared”.

   - gh-105387(42): In the limited C API version 3.12, *note
     Py_INCREF(): 571. and *note Py_DECREF(): 572. functions are now
     implemented as opaque function calls to hide implementation
     details.  Patch by Victor Stinner.

   - gh-105396(43): Deprecate the *note PyImport_ImportModuleNoBlock():
     3c0. function which is just an alias to *note
     PyImport_ImportModule(): 3c1. since Python 3.3.  Patch by Victor
     Stinner.

   - gh-103968(44): *note PyType_FromMetaclass(): 553. now allows
     metaclasses with ‘tp_new’ set to ‘NULL’.

   - gh-105268(45): Remove the old private, undocumented and untested
     ‘_PyGC_FINALIZED()’ macro which was kept for backward compatibility
     with Python 3.8 and older.  Patch by Victor Stinner.

   - gh-105182(46): Remove ‘PyEval_AcquireLock()’ and
     ‘PyEval_ReleaseLock()’ functions, deprecated in Python 3.2.  Patch
     by Victor Stinner.

   - gh-105182(47): Remove ‘PyEval_InitThreads()’ and
     ‘PyEval_ThreadsInitialized()’ functions, deprecated in Python 3.9.
     Patch by Victor Stinner.

   - gh-105145(48): Deprecate old Python initialization functions:

        * *note PySys_ResetWarnOptions(): 3b2.

        * *note Py_GetExecPrefix(): 3b4.

        * *note Py_GetPath(): 3b6.

        * *note Py_GetPrefix(): 3b8.

        * *note Py_GetProgramFullPath(): 3ba.

        * *note Py_GetProgramName(): 3bc.

        * *note Py_GetPythonHome(): 3bd.

     Patch by Victor Stinner.

   - gh-85275(49): ‘PyObject_AsCharBuffer()’, ‘PyObject_AsReadBuffer()’,
     ‘PyObject_CheckReadBuffer()’, and ‘PyObject_AsWriteBuffer()’ are
     removed.  Please migrate to new buffer protocol; *note
     PyObject_GetBuffer(): 39c. and *note PyBuffer_Release(): 39d.

   - gh-105156(50): Deprecate the old ‘Py_UNICODE’ and ‘PY_UNICODE_TYPE’
     types: use directly the ‘wchar_t’ type instead.  Since Python 3.3,
     ‘Py_UNICODE’ and ‘PY_UNICODE_TYPE’ are just aliases to ‘wchar_t’.
     Patch by Victor Stinner.

   - gh-105145(51): Remove the following old functions to configure the
     Python initialization, deprecated in Python 3.11:

        * ‘PySys_AddWarnOptionUnicode()’

        * ‘PySys_AddWarnOption()’

        * ‘PySys_AddXOption()’

        * ‘PySys_HasWarnOptions()’

        * ‘PySys_SetArgvEx()’

        * ‘PySys_SetArgv()’

        * ‘PySys_SetPath()’

        * ‘Py_SetPath()’

        * ‘Py_SetProgramName()’

        * ‘Py_SetPythonHome()’

        * ‘Py_SetStandardStreamEncoding()’

        * ‘_Py_SetProgramFullPath()’

     Patch by Victor Stinner.

   - gh-105107(52): Remove functions deprecated in Python 3.9.

        * ‘PyEval_CallObject()’, ‘PyEval_CallObjectWithKeywords()’: use
          *note PyObject_CallNoArgs(): 39e. and *note PyObject_Call():
          39f. (positional arguments must not be 'NULL') instead.

        * ‘PyEval_CallFunction()’: use *note PyObject_CallFunction():
          3a1. instead.

        * ‘PyEval_CallMethod()’: use *note PyObject_CallMethod(): 3a2.
          instead.

        * ‘PyCFunction_Call()’: use *note PyObject_Call(): 39f. instead.

     Patch by Victor Stinner.

   - gh-105115(53): ‘PyTypeObject.tp_bases’ (and ‘tp_mro’) for builtin
     static types are now shared by all interpreters, whereas in
     3.12-beta1 they were stored on ‘PyInterpreterState’.  Also note
     that now the tuples are immortal objects.

   - gh-105071(54): Add ‘PyUnstable_Exc_PrepReraiseStar’ to the unstable
     C api to expose the implementation of *note except*: 5bb.

   - gh-104922(55): ‘PY_SSIZE_T_CLEAN’ is no longer required to use
     ‘'#'’ formats in APIs like *note PyArg_ParseTuple(): 574. and *note
     Py_BuildValue(): 8af.  They uses ‘Py_ssize_t’ for ‘'#'’ regardless
     ‘PY_SSIZE_T_CLEAN’.

   - gh-104584(56): Add an unstable C API for hooking in an optimizer.
     This is mainly internal, but marked “unstable” to allow third-party
     experimentation.

   - gh-104668(57): Don’t call *note PyOS_InputHook: 588. or *note
     PyOS_ReadlineFunctionPointer: 589. in subinterpreters, since it’s
     generally difficult to avoid using global state in their registered
     callbacks.  This also avoids situations where extensions may find
     themselves running in a subinterpreter they don’t support (or
     haven’t yet been loaded in).

   - bpo-42327(58): Add *note PyModule_Add(): 367. function: similar to
     *note PyModule_AddObjectRef(): 368. and *note PyModule_AddObject():
     369, but always steals a reference to the value.

   - bpo-40309(59): Properly handle trailing spaces before closing
     parenthesis in *note Py_BuildValue(): 8af. format strings.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/85283

   (2) https://github.com/python/cpython/issues/110289

   (3) https://github.com/python/cpython/issues/110235

   (4) https://github.com/python/cpython/issues/110014

   (5) https://github.com/python/cpython/issues/109521

   (6) https://github.com/python/cpython/issues/108724

   (7) https://github.com/python/cpython/issues/85283

   (8) https://github.com/python/cpython/issues/108867

   (9) https://github.com/python/cpython/issues/108765

   (10) https://github.com/python/cpython/issues/108765

   (11) https://github.com/python/cpython/issues/108765

   (12) https://github.com/python/cpython/issues/108765

   (13) https://github.com/python/cpython/issues/108511

   (14) https://github.com/python/cpython/issues/107073

   (15) https://github.com/python/cpython/issues/108634

   (16) https://github.com/python/cpython/issues/108014

   (17) https://github.com/python/cpython/issues/108314

   (18) https://github.com/python/cpython/issues/108337

   (19) https://github.com/python/cpython/issues/108014

   (20) https://github.com/python/cpython/issues/107916

   (21) https://github.com/python/cpython/issues/107915

   (22) https://github.com/python/cpython/issues/107810

   (23) https://github.com/python/cpython/issues/107249

   (24) https://github.com/python/cpython/issues/107226

   (25) https://github.com/python/cpython/issues/106320

   (26) https://github.com/python/cpython/issues/106572

   (27) https://github.com/python/cpython/issues/106307

   (28) https://github.com/python/cpython/issues/106521

   (29) https://github.com/python/cpython/issues/106320

   (30) https://github.com/python/cpython/issues/106316

   (31) https://github.com/python/cpython/issues/106023

   (32) https://peps.python.org/pep-0590/

   (33) https://github.com/python/cpython/issues/106168

   (34) https://github.com/python/cpython/issues/106084

   (35) https://github.com/python/cpython/issues/106004

   (36) https://github.com/python/cpython/issues/105927

   (37) https://github.com/python/cpython/issues/105927

   (38) https://github.com/python/cpython/issues/105922

   (39) https://github.com/python/cpython/issues/105227

   (40) https://github.com/python/cpython/issues/105375

   (41) https://github.com/python/cpython/issues/105603

   (42) https://github.com/python/cpython/issues/105387

   (43) https://github.com/python/cpython/issues/105396

   (44) https://github.com/python/cpython/issues/103968

   (45) https://github.com/python/cpython/issues/105268

   (46) https://github.com/python/cpython/issues/105182

   (47) https://github.com/python/cpython/issues/105182

   (48) https://github.com/python/cpython/issues/105145

   (49) https://github.com/python/cpython/issues/85275

   (50) https://github.com/python/cpython/issues/105156

   (51) https://github.com/python/cpython/issues/105145

   (52) https://github.com/python/cpython/issues/105107

   (53) https://github.com/python/cpython/issues/105115

   (54) https://github.com/python/cpython/issues/105071

   (55) https://github.com/python/cpython/issues/104922

   (56) https://github.com/python/cpython/issues/104584

   (57) https://github.com/python/cpython/issues/104668

   (58) https://bugs.python.org/issue?@action=redirect&bpo=42327

   (59) https://bugs.python.org/issue?@action=redirect&bpo=40309


File: python.info,  Node: Python 3 12 0 beta 1,  Next: Python 3 12 0 alpha 7,  Prev: Python 3 13 0 alpha 1,  Up: Changelog

1.23.28 Python 3.12.0 beta 1
----------------------------

'Release date: 2023-05-22'

* Menu:

* Security: Security<19>.
* Library: Library<40>.
* Core and Builtins: Core and Builtins<36>.
* Library: Library<41>.
* Core and Builtins: Core and Builtins<37>.
* Library: Library<42>.
* Core and Builtins: Core and Builtins<38>.
* Library: Library<43>.
* Documentation: Documentation<19>.
* Tests: Tests<22>.
* Build: Build<22>.
* Windows: Windows<20>.
* macOS: macOS<15>.
* IDLE: IDLE<18>.
* Tools/Demos: Tools/Demos<13>.
* C API: C API<22>.


File: python.info,  Node: Security<19>,  Next: Library<40>,  Up: Python 3 12 0 beta 1

1.23.28.1 Security
..................

   - gh-99889(1): Fixed a security in flaw in ‘uu.decode()’ that could
     allow for directory traversal based on the input if no ‘out_file’
     was specified.

   - gh-104049(2): Do not expose the local on-disk location in directory
     indexes produced by ‘http.client.SimpleHTTPRequestHandler’.

   - gh-99108(3): Upgrade built-in *note hashlib: 68. SHA3
     implementation to a verified implementation from the ‘HACL*’
     project.  Used when OpenSSL is not present or lacks SHA3.

   - gh-102153(4): *note urllib.parse.urlsplit(): d67. now strips
     leading C0 control and space characters following the specification
     for URLs defined by WHATWG in response to CVE 2023-24329(5).  Patch
     by Illia Volochii.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99889

   (2) https://github.com/python/cpython/issues/104049

   (3) https://github.com/python/cpython/issues/99108

   (4) https://github.com/python/cpython/issues/102153

   (5) https://www.cve.org/CVERecord?id=CVE-2023-24329


File: python.info,  Node: Library<40>,  Next: Core and Builtins<36>,  Prev: Security<19>,  Up: Python 3 12 0 beta 1

1.23.28.2 Library
.................

   - gh-102856(1): Implement PEP 701 changes in the *note tokenize: fb.
     module.  Patch by Marta Gómez Macías and Pablo Galindo Salgado

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102856


File: python.info,  Node: Core and Builtins<36>,  Next: Library<41>,  Prev: Library<40>,  Up: Python 3 12 0 beta 1

1.23.28.3 Core and Builtins
...........................

   - gh-104615(1): Fix wrong ordering of assignments in code like ‘a, a
     = x, y’.  Contributed by Carl Meyer.

   - gh-104572(2): Improve syntax error message for invalid constructs
     in PEP 695(3) contexts and in annotations when ‘from __future__
     import annotations’ is active.

   - gh-104482(4): Fix three error handling bugs in ast.c’s validation
     of pattern matching statements.

   - gh-102818(5): Do not add a frame to the traceback in the
     ‘sys.setprofile’ and ‘sys.settrace’ trampoline functions.  This
     ensures that frames are not duplicated if an exception is raised in
     the callback function, and ensures that frames are not omitted if a
     C callback is used and that does not add the frame.

   - gh-104405(6): Fix an issue where some *note bytecode: 187.
     instructions could ignore PEP 523(7) when “inlining” calls.

   - gh-103082(8): Change behavior of ‘sys.monitoring.events.LINE’
     events in ‘sys.monitoring’: Line events now occur when a new line
     is reached dynamically, instead of using a static approximation, as
     before.  This makes the behavior very similar to that of “line”
     events in ‘sys.settrace’.  This should ease porting of tools from
     3.11 to 3.12.

   - gh-104263(9): Fix ‘float("nan")’ to produce a quiet NaN on
     platforms (like MIPS) where the meaning of the signalling / quiet
     bit is inverted from its usual meaning.  Also introduce a new macro
     ‘Py_INFINITY’ matching C99’s ‘INFINITY’, and refactor internals to
     rely on C99’s ‘NAN’ and ‘INFINITY’ macros instead of hard-coding
     bit patterns for infinities and NaNs.  Thanks Sebastian Berg.

   - gh-99113(10): Multi-phase init extension modules may now indicate
     that they support running in subinterpreters that have their own
     GIL. This is done by using ‘Py_MOD_PER_INTERPRETER_GIL_SUPPORTED’
     as the value for the ‘Py_mod_multiple_interpreters’ module def
     slot.  Otherwise the module, by default, cannot be imported in such
     subinterpreters.  (This does not affect the main interpreter or
     subinterpreters that do not have their own GIL.) In addition to the
     isolation that multi-phase init already normally requires, support
     for per-interpreter GIL involves one additional constraint:
     thread-safety.  If the module has external (linked) dependencies
     and those libraries have any state that isn’t thread-safe then the
     module must do the additional work to add thread-safety.  This
     should be an uncommon case.

   - gh-99113(11): The GIL is now (optionally) per-interpreter.  This is
     the fundamental change for PEP 684.  This is all made possible by
     virtue of the isolated state of each interpreter in the process.
     The behavior of the main interpreter remains unchanged.  Likewise,
     interpreters created using ‘Py_NewInterpreter()’ are not affected.
     To get an interpreter with its own GIL, call
     ‘Py_NewInterpreterFromConfig()’.

   - gh-104108(12): Multi-phase init extension modules may now indicate
     whether or not they actually support multiple interpreters.  By
     default such modules are expected to support use in multiple
     interpreters.  In the uncommon case that one does not, it may use
     the new ‘Py_mod_multiple_interpreters’ module def slot.  A value of
     ‘0’ means the module does not support them.  ‘1’ means it does.
     The default is ‘1’.

   - gh-104142(13): Fix an issue where *note list: 614. or *note tuple:
     373. repetition could fail to respect PEP 683(14).

   - gh-104078(15): Improve the performance of *note
     PyObject_HasAttrString(): 380.

   - gh-104066(16): Improve the performance of *note hasattr(): 4d5. for
     module objects with a missing attribute.

   - gh-104028(17): Reduce object creation while calling callback
     function from gc.  Patch by Donghee Na.

   - gh-104018(18): Disallow the “z” format specifier in %-format of
     bytes objects.

   - gh-102213(19): Fix performance loss when accessing an object’s
     attributes with ‘__getattr__’ defined.

   - gh-103895(20): Improve handling of edge cases in showing
     ‘Exception.__notes__’.  Ensures that the messages always end with a
     newline and that string/bytes are not exploded over multiple lines.
     Patch by Carey Metcalfe.

   - gh-103907(21): Don’t modify the refcounts of known immortal objects
     (*note True: c2d, *note False: b4f, and *note None: 678.) in the
     main interpreter loop.

   - gh-103899(22): Provide a helpful hint in the *note TypeError: 2c3.
     message when accidentally calling a *note module: 1772. object that
     has a callable attribute of the same name (such as *note dis.dis():
     b4c. or *note datetime.datetime: 1cc.).

   - gh-103845(23): Remove both line and instruction instrumentation
     before adding new ones for monitoring, to avoid newly added
     instrumentation being removed immediately.

   - gh-103763(24): Implement PEP 695(25), adding syntactic support for
     generic classes, generic functions, and type aliases.

     A new ‘type X = ...’ syntax is added for type aliases, which
     resolves at runtime to an instance of the new class
     ‘typing.TypeAliasType’.  The value is lazily evaluated and is
     accessible through the ‘.__value__’ attribute.  This is implemented
     as a new AST node ‘ast.TypeAlias’.

     New syntax (‘class X[T]: ...’, ‘def func[T](): ...’) is added for
     defining generic functions and classes.  This is implemented as a
     new ‘type_params’ attribute on the AST nodes for classes and
     functions.  This node holds instances of the new AST classes
     ‘ast.TypeVar’, ‘ast.ParamSpec’, and ‘ast.TypeVarTuple’.

     ‘typing.TypeVar’, ‘typing.ParamSpec’, ‘typing.ParamSpecArgs’,
     ‘typing.ParamSpecKwargs’, ‘typing.TypeVarTuple’, and
     ‘typing.Generic’ are now implemented in C rather than Python.

     There are new bytecode instructions ‘LOAD_LOCALS’,
     ‘LOAD_CLASSDICT_OR_GLOBAL’, and ‘LOAD_CLASSDICT_OR_DEREF’ to
     support correct resolution of names in class namespaces.

     Patch by Eric Traut, Larry Hastings, and Jelle Zijlstra.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104615

   (2) https://github.com/python/cpython/issues/104572

   (3) https://peps.python.org/pep-0695/

   (4) https://github.com/python/cpython/issues/104482

   (5) https://github.com/python/cpython/issues/102818

   (6) https://github.com/python/cpython/issues/104405

   (7) https://peps.python.org/pep-0523/

   (8) https://github.com/python/cpython/issues/103082

   (9) https://github.com/python/cpython/issues/104263

   (10) https://github.com/python/cpython/issues/99113

   (11) https://github.com/python/cpython/issues/99113

   (12) https://github.com/python/cpython/issues/104108

   (13) https://github.com/python/cpython/issues/104142

   (14) https://peps.python.org/pep-0683/

   (15) https://github.com/python/cpython/issues/104078

   (16) https://github.com/python/cpython/issues/104066

   (17) https://github.com/python/cpython/issues/104028

   (18) https://github.com/python/cpython/issues/104018

   (19) https://github.com/python/cpython/issues/102213

   (20) https://github.com/python/cpython/issues/103895

   (21) https://github.com/python/cpython/issues/103907

   (22) https://github.com/python/cpython/issues/103899

   (23) https://github.com/python/cpython/issues/103845

   (24) https://github.com/python/cpython/issues/103763

   (25) https://peps.python.org/pep-0695/


File: python.info,  Node: Library<41>,  Next: Core and Builtins<37>,  Prev: Core and Builtins<36>,  Up: Python 3 12 0 beta 1

1.23.28.4 Library
.................

   - gh-103801(1): Adds three minor linting fixes to the wasm module
     caught that were caught by ruff.

   - gh-103793(2): Optimized asyncio Task creation by deferring
     expensive string formatting (task name generation) from Task
     creation to the first time ‘get_name’ is called.  This makes
     asyncio benchmarks up to 5% faster.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103801

   (2) https://github.com/python/cpython/issues/103793


File: python.info,  Node: Core and Builtins<37>,  Next: Library<42>,  Prev: Library<41>,  Up: Python 3 12 0 beta 1

1.23.28.5 Core and Builtins
...........................

   - gh-102310(1): Change the error range for invalid bytes literals.

   - gh-103590(2): Do not wrap a single exception raised from a
     ‘try-except*’ construct in an *note ExceptionGroup: 1b6.

   - gh-103650(3): Change the perf map format to remove the ‘0x’ prefix
     from the addresses

   - gh-102856(4): Implement the required C tokenizer changes for PEP
     701.  Patch by Pablo Galindo Salgado, Lysandros Nikolaou, Batuhan
     Taskaya, Marta Gómez Macías and sunmy2019.

   - gh-100530(5): Clarify the error message raised when the called part
     of a class pattern isn’t actually a class.

   - gh-101517(6): Fix bug in line numbers of instructions emitted for
     *note except*: 5bb.

   - gh-103492(7): Clarify *note SyntaxWarning: 469. with literal ‘is’
     comparison by specifying which literal is problematic, since
     comparisons using ‘is’ with e.g.  ‘None’ and bool literals are
     idiomatic.

   - gh-87729(8): Add *note LOAD_SUPER_ATTR: 4df. (and a specialization
     for ‘super().method()’) to speed up ‘super().method()’ and
     ‘super().attr’.  This makes ‘super().method()’ roughly 2.3x faster
     and brings it within 20% of the performance of a simple method
     call.  Patch by Vladimir Matveev and Carl Meyer.

   - gh-103488(9): Change the internal offset distinguishing yield and
     return target addresses, so that the instruction pointer is correct
     for exception handling and other stack unwinding.

   - gh-82012(10): The bitwise inversion operator (‘~’) on bool is
     deprecated.  It returns the bitwise inversion of the underlying
     ‘int’ representation such that ‘bool(~True) == True’, which can be
     confusing.  Use ‘not’ for logical negation of bools.  In the rare
     case that you really need the bitwise inversion of the underlying
     ‘int’, convert to int explicitly ‘~int(x)’.

   - gh-77757(11): Exceptions raised in a typeobject’s ‘__set_name__’
     method are no longer wrapped by a *note RuntimeError: 195.  Context
     information is added to the exception as a PEP 678(12) note.

   - gh-103333(13): *note AttributeError: 34e. now retains the ‘name’
     attribute when pickled and unpickled.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102310

   (2) https://github.com/python/cpython/issues/103590

   (3) https://github.com/python/cpython/issues/103650

   (4) https://github.com/python/cpython/issues/102856

   (5) https://github.com/python/cpython/issues/100530

   (6) https://github.com/python/cpython/issues/101517

   (7) https://github.com/python/cpython/issues/103492

   (8) https://github.com/python/cpython/issues/87729

   (9) https://github.com/python/cpython/issues/103488

   (10) https://github.com/python/cpython/issues/82012

   (11) https://github.com/python/cpython/issues/77757

   (12) https://peps.python.org/pep-0678/

   (13) https://github.com/python/cpython/issues/103333


File: python.info,  Node: Library<42>,  Next: Core and Builtins<38>,  Prev: Core and Builtins<37>,  Up: Python 3 12 0 beta 1

1.23.28.6 Library
.................

   - gh-103242(1): Migrate *note set_ecdh_curve(): 1187. method not to
     use deprecated OpenSSL APIs.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103242


File: python.info,  Node: Core and Builtins<38>,  Next: Library<43>,  Prev: Library<42>,  Up: Python 3 12 0 beta 1

1.23.28.7 Core and Builtins
...........................

   - gh-103323(1): We’ve replaced our use of ‘_PyRuntime.tstate_current’
     with a thread-local variable.  This is a fairly low-level
     implementation detail, and there should be no change in behavior.

   - gh-84436(2): The implementation of PEP-683 which adds Immortal
     Objects by using a fixed reference count that skips reference
     counting to make objects truly immutable.

   - gh-102700(3): Allow built-in modules to be submodules.  This allows
     submodules to be statically linked into a CPython binary.

   - gh-103082(4): Implement PEP 669(5) Low Impact Monitoring for
     CPython.

   - gh-88691(6): Reduce the number of inline *note CACHE: 6fc. entries
     for *note CALL: 70a.

   - gh-102500(7): Make the buffer protocol accessible in Python code
     using the new ‘__buffer__’ and ‘__release_buffer__’ magic methods.
     See PEP 688(8) for details.  Patch by Jelle Zijlstra.

   - gh-97933(9): PEP 709(10): inline list, dict and set comprehensions
     to improve performance and reduce bytecode size.

   - gh-99184(11): Bypass instance attribute access of ‘__name__’ in
     ‘repr’ of *note weakref.ref: 102b.

   - gh-98003(12): Complex function calls are now faster and consume no
     C stack space.

   - bpo-39610(13): ‘len()’ for 0-dimensional *note memoryview: 2eb.
     objects (such as ‘memoryview(ctypes.c_uint8(42))’) now raises a
     *note TypeError: 2c3.  Previously this returned ‘1’, which was not
     consistent with ‘mem_0d[0]’ raising an *note IndexError: 1585.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103323

   (2) https://github.com/python/cpython/issues/84436

   (3) https://github.com/python/cpython/issues/102700

   (4) https://github.com/python/cpython/issues/103082

   (5) https://peps.python.org/pep-0669/

   (6) https://github.com/python/cpython/issues/88691

   (7) https://github.com/python/cpython/issues/102500

   (8) https://peps.python.org/pep-0688/

   (9) https://github.com/python/cpython/issues/97933

   (10) https://peps.python.org/pep-0709/

   (11) https://github.com/python/cpython/issues/99184

   (12) https://github.com/python/cpython/issues/98003

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39610


File: python.info,  Node: Library<43>,  Next: Documentation<19>,  Prev: Core and Builtins<38>,  Up: Python 3 12 0 beta 1

1.23.28.8 Library
.................

   - bpo-31821(1): Fix ‘pause_reading()’ to work when called from
     ‘connection_made()’ in *note asyncio: a.

   - gh-104600(2): *note functools.update_wrapper(): 105d. now sets the
     ‘__type_params__’ attribute (added by PEP 695(3)).

   - gh-104340(4): When an ‘asyncio’ pipe protocol loses its connection
     due to an error, and the caller doesn’t await ‘wait_closed()’ on
     the corresponding ‘StreamWriter’, don’t log a warning about an
     exception that was never retrieved.  After all, according to the
     ‘StreamWriter.close()’ docs, the ‘wait_closed()’ call is optional
     (“not mandatory”).

   - gh-104555(5): Fix issue where an *note issubclass(): 7c5. check
     comparing a class ‘X’ against a *note runtime-checkable protocol:
     446. ‘Y’ with non-callable members would not cause *note TypeError:
     2c3. to be raised if an *note isinstance(): 445. call had
     previously been made comparing an instance of ‘X’ to ‘Y’.  This
     issue was present in edge cases on Python 3.11, but became more
     prominent in 3.12 due to some unrelated changes that were made to
     runtime-checkable protocols.  Patch by Alex Waygood.

   - gh-104372(6): Refactored the ‘_posixsubprocess’ internals to avoid
     Python C API usage between fork and exec when marking ‘pass_fds=’
     file descriptors inheritable.

   - gh-104484(7): Added 'case_sensitive' argument to *note
     pathlib.PurePath.match(): 4af.

   - gh-75367(8): Fix data descriptor detection in *note
     inspect.getattr_static(): 497.

   - gh-104536(9): Fix a race condition in the internal
     ‘multiprocessing.process’ cleanup logic that could manifest as an
     unintended ‘AttributeError’ when calling ‘process.close()’.

   - gh-103857(10): Update datetime deprecations’ stracktrace to point
     to the calling line

   - gh-101520(11): Move the core functionality of the ‘tracemalloc’
     module in the ‘Python/’ folder, leaving just the module wrapper in
     ‘Modules/’.

   - gh-104392(12): Remove undocumented and unused ‘_paramspec_tvars’
     attribute from some classes in *note typing: 104.

   - gh-102613(13): Fix issue where *note pathlib.Path.glob(): 22d.
     raised *note RecursionError: d96. when walking deep directory
     trees.

   - gh-103000(14): Improve performance of *note dataclasses.asdict():
     1836. for the common case where 'dict_factory' is ‘dict’.  Patch by
     David C Ellis.

   - gh-104301(15): Allow leading whitespace in disambiguated statements
     in *note pdb: a5.

   - gh-104139(16): Teach ‘urllib.parse.unsplit()’ to retain the ‘"//"’
     when assembling ‘itms-services://?action=generate-bugs’ style Apple
     Platform Deployment(17) URLs.

   - gh-104307(18): *note socket.getnameinfo(): 17d3. now releases the
     GIL while contacting the DNS server

   - gh-104310(19): Users may now use
     ‘importlib.util.allowing_all_extensions()’ (a context manager) to
     temporarily disable the strict compatibility checks for importing
     extension modules in subinterpreters.

   - gh-87695(20): Fix issue where *note pathlib.Path.glob(): 22d.
     raised *note OSError: 41a. when it encountered a symlink to an
     overly long path.

   - gh-104265(21): Prevent possible crash by disallowing instantiation
     of the ‘_csv.Reader’ and ‘_csv.Writer’ types.  The regression was
     introduced in 3.10.0a4 with PR 23224 (bpo-14935(22)).  Patch by
     Radislav Chugunov.

   - gh-102613(23): Improve performance of *note pathlib.Path.glob():
     22d. when expanding recursive wildcards (”‘**’”) by merging
     adjacent wildcards and de-duplicating results only when necessary.

   - gh-65772(24): Remove unneeded comments and code in turtle.py.

   - gh-90208(25): Fixed issue where *note pathlib.Path.glob(): 22d.
     returned incomplete results when it encountered a *note
     PermissionError: d6b.  This method now suppresses all *note
     OSError: 41a. exceptions, except those raised from calling *note
     is_dir(): 230. on the top-level path.

   - gh-104144(26): Optimize *note asyncio.TaskGroup: 1b5. when using
     *note asyncio.eager_task_factory(): 47a.  Skip scheduling a done
     callback if a TaskGroup task completes eagerly.

   - gh-104144(27): Optimize *note asyncio.gather(): 600. when using
     *note asyncio.eager_task_factory(): 47a. to complete eagerly if all
     fututres completed eagerly.  Avoid scheduling done callbacks for
     futures that complete eagerly.

   - gh-104114(28): Fix issue where *note pathlib.Path.glob(): 22d.
     returns paths using the case of non-wildcard segments for
     corresponding path segments, rather than the real filesystem case.

   - gh-104104(29): Improve performance of *note pathlib.Path.glob():
     22d. by using *note re.IGNORECASE: 1837. to implement
     case-insensitive matching.

   - gh-104102(30): Improve performance of *note pathlib.Path.glob():
     22d. when evaluating patterns that contain ‘'../'’ segments.

   - gh-103822(31): Update the return type of ‘weekday’ to the newly
     added Day attribute

   - gh-103629(32): Update the ‘repr’ of *note typing.Unpack: 1738.
     according to PEP 692(33).

   - gh-103963(34): Make *note dis: 38. display the names of the args
     for ‘CALL_INTRINSIC_*’.

   - gh-104035(35): Do not ignore user-defined ‘__getstate__’ and
     ‘__setstate__’ methods for slotted frozen dataclasses.

   - gh-103987(36): In *note mmap: 90, fix several bugs that could lead
     to access to memory-mapped files after they have been invalidated.

   - gh-103977(37): Improve import time of *note platform: aa. module.

   - gh-88773(38): Added *note turtle.teleport(): 1838. to the *note
     turtle: 101. module to move a turtle to a new point without tracing
     a line, visible or invisible.  Patch by Liam Gersten.

   - gh-103935(39): Use *note io.open_code(): 15a7. for files to be
     executed instead of raw *note open(): 51f.

   - gh-68968(40): Fixed garbled output of *note assertEqual(): 52c.
     when an input lacks final newline.

   - gh-100370(41): Fix potential *note OverflowError: 888. in *note
     sqlite3.Connection.blobopen(): 684. for 32-bit builds.  Patch by
     Erlend E. Aasland.

   - gh-102628(42): Substitute CTRL-D with CTRL-Z in *note sqlite3: cf.
     CLI banner when running on Windows.

   - gh-103636(43): Module-level attributes ‘January’ and ‘February’ are
     deprecated from *note calendar: 14.

   - gh-103583(44): Isolate ‘_multibytecodec’ and codecs extension
     modules.  Patches by Erlend E. Aasland.

   - gh-103848(45): Add checks to ensure that ‘[’ bracketed ‘]’ hosts
     found by *note urllib.parse.urlsplit(): d67. are of IPv6 or
     IPvFuture format.

   - gh-103872(46): Update the bundled copy of pip to version 23.1.2.

   - gh-99944(47): Make *note dis: 38. display the value of oparg of
     ‘KW_NAMES’.

   - gh-74940(48): The C.UTF-8 locale is no longer converted to
     en_US.UTF-8, enabling the use of UTF-8 encoding on systems which
     have no locales installed.

   - gh-103861(49): Fix ‘zipfile.Zipfile’ creating invalid zip files
     when ‘force_zip64’ was used to add files to them.  Patch by Carey
     Metcalfe.

   - gh-103857(50): Deprecated *note datetime.datetime.utcnow(): 2fc.
     and *note datetime.datetime.utcfromtimestamp(): 2fd.  (Patch by
     Paul Ganssle)

   - gh-103839(51): Avoid compilation error due to tommath.h not being
     found when building Tkinter against Tcl 8.7 built with bundled
     libtommath.

   - gh-103791(52): *note contextlib.suppress: f5d. now supports
     suppressing exceptions raised as part of an *note ExceptionGroup:
     1b6.  If other exceptions exist on the group, they are re-raised in
     a group that does not contain the suppressed exceptions.

   - gh-90750(53): Use *note datetime.datetime.fromisocalendar(): 9f8.
     in the implementation of *note datetime.datetime.strptime(): 1714,
     which should now accept only valid ISO dates.  (Patch by Paul
     Ganssle)

   - gh-103685(54): Prepare ‘tkinter.Menu.index()’ for Tk 8.7 so that it
     does not raise ‘TclError: expected integer but got ""’ when it
     should return ‘None’.

   - gh-81403(55): *note urllib.request.CacheFTPHandler: 1839. no longer
     raises ‘URLError’ if a cached FTP instance is reused.  ftplib’s
     endtransfer method calls voidresp to drain the connection to handle
     FTP instance reuse properly.

   - gh-103699(56): Add ‘__orig_bases__’ to non-generic TypedDicts,
     call-based TypedDicts, and call-based NamedTuples.  Other
     TypedDicts and NamedTuples already had the attribute.

   - gh-103693(57): Add convenience variable feature to *note pdb: a5.

   - gh-92248(58): Deprecate ‘type’, ‘choices’, and ‘metavar’ parameters
     of ‘argparse.BooleanOptionalAction’.

   - gh-89415(59): Add *note socket: cc. constants for source-specific
     multicast.  Patch by Reese Hyde.

   - gh-103673(60): *note socketserver: cd. gains
     ‘ForkingUnixStreamServer’ and ‘ForkingUnixDatagramServer’ classes.
     Patch by Jay Berry.

   - gh-103636(61): Added Enum for months and days in the calendar
     module.

   - gh-84976(62): Create a new ‘Lib/_pydatetime.py’ file that defines
     the Python version of the ‘datetime’ module, and make ‘datetime’
     import the contents of the new library only if the C implementation
     is missing.  Currently, the full Python implementation is defined
     and then deleted if the C implementation is not available, slowing
     down ‘import datetime’ unnecessarily.

   - gh-103596(63): Attributes/methods are no longer shadowed by
     same-named enum members, although they may be shadowed by
     enum.property’s.

   - gh-103584(64): Updated ‘importlib.metadata’ with changes from
     ‘importlib_metadata’ 5.2 through 6.5.0, including: Support
     ‘installed-files.txt’ for ‘Distribution.files’ when present.
     ‘PackageMetadata’ now stipulates an additional ‘get’ method
     allowing for easy querying of metadata keys that may not be
     present.  ‘packages_distributions’ now honors packages and modules
     with Python modules that not ‘.py’ sources (e.g.  ‘.pyc’, ‘.so’).
     Expand protocol for ‘PackageMetadata.get_all’ to match the upstream
     implementation of ‘email.message.Message.get_all’ in
     python/typeshed#9620.  Deprecated use of ‘Distribution’ without
     defining abstract methods.  Deprecated expectation that
     ‘PackageMetadata.__getitem__’ will return ‘None’ for missing keys.
     In the future, it will raise a ‘KeyError’.

   - gh-103578(65): Fixed a bug where *note pdb: a5. crashes when
     reading source file with different encoding by replacing *note
     io.open(): 520. with *note io.open_code(): 15a7.  The new method
     would also call into the hook set by *note
     PyFile_SetOpenCodeHook(): 183a.

   - gh-103556(66): Now creating *note inspect.Signature: 1cf. objects
     with positional-only parameter with a default followed by a
     positional-or-keyword parameter without one is impossible.

   - gh-103559(67): Update the bundled copy of pip to version 23.1.1.

   - gh-103548(68): Improve performance of *note
     pathlib.Path.absolute(): 17bf. and *note cwd(): 183b. by joining
     paths only when necessary.  Also improve performance of *note
     pathlib.PurePath.is_absolute(): 183c. on Posix by skipping path
     parsing and normalization.

   - gh-103538(69): Remove ‘_tkinter’ module code guarded by definition
     of the ‘TK_AQUA’ macro which was only needed for Tk 8.4.7 or
     earlier and was never actually defined by any build system or
     documented for manual use.

   - gh-103533(70): Update *note cProfile: 27. to use PEP 669 API

   - gh-103525(71): Fix misleading exception message when mixed ‘str’
     and ‘bytes’ arguments are supplied to *note pathlib.PurePath: 4a9.
     and *note Path: 229.

   - gh-103489(72): Add *note getconfig(): 4bc. and *note setconfig():
     4bd. to *note Connection: 245. to make configuration changes to a
     database connection.  Patch by Erlend E. Aasland.

   - gh-103365(73): Set default Flag boundary to ‘STRICT’ and fix
     bitwise operations.

   - gh-103472(74): Avoid a potential *note ResourceWarning: 244. in
     *note http.client.HTTPConnection: b59. by closing the proxy /
     tunnel’s CONNECT response explicitly.

   - gh-103462(75): Fixed an issue with using *note writelines(): 1600.
     in *note asyncio: a. to send very large payloads that exceed the
     amount of data that can be written in one call to *note
     socket.socket.send(): dd5. or *note socket.socket.sendmsg(): 479,
     resulting in the remaining buffer being left unwritten.

   - gh-103449(76): Fix a bug in doc string generation in *note
     dataclasses.dataclass(): 1cb.

   - gh-103092(77): Isolate ‘_collections’ (apply PEP 687(78)).  Patch
     by Erlend E. Aasland.

   - gh-103357(79): Added support for *note logging.Formatter: 14e6.
     ‘defaults’ parameter to *note logging.config.dictConfig(): 11f4.
     and *note logging.config.fileConfig(): b6c.  Patch by Bar Harel.

   - gh-103092(80): Adapt the *note winreg: 116. extension module to PEP
     687(81).

   - gh-74690(82): The performance of *note isinstance(): 445. checks
     against *note runtime-checkable protocols: 446. has been
     considerably improved for protocols that only have a few members.
     To achieve this improvement, several internal implementation
     details of the *note typing: 104. module have been refactored,
     including ‘typing._ProtocolMeta.__instancecheck__’,
     ‘typing._is_callable_members_only’, and
     ‘typing._get_protocol_attrs’.  Patches by Alex Waygood.

   - gh-74690(83): The members of a runtime-checkable protocol are now
     considered “frozen” at runtime as soon as the class has been
     created.  See *note “What’s new in Python 3.12”: 4d4. for more
     details.

   - gh-103256(84): Fixed a bug that caused *note hmac: 6a. to raise an
     exception when the requested hash algorithm was not available in
     OpenSSL despite being available separately as part of ‘hashlib’
     itself.  It now falls back properly to the built-in.  This could
     happen when, for example, your OpenSSL does not include SHA3
     support and you want to compute ‘hmac.digest(b'K', b'M',
     'sha3_256')’.

   - gh-102778(85): Support ‘sys.last_exc’ in *note idlelib: 73.

   - gh-103285(86): Improve performance of *note
     ast.get_source_segment(): 9e3.

   - gh-103225(87): Fix a bug in *note pdb: a5. when displaying line
     numbers of module-level source code.

   - gh-103092(88): Adapt the *note msvcrt: 93. extension module to PEP
     687(89).

   - gh-103092(90): Adapt the *note winsound: 117. extension module to
     PEP 687(91).

   - gh-93910(92): Remove deprecation of enum ‘member.member’ access.

   - gh-102978(93): Fixes *note unittest.mock.patch(): ec6. not
     enforcing function signatures for methods decorated with
     ‘@classmethod’ or ‘@staticmethod’ when patch is called with
     ‘autospec=True’.

   - gh-103092(94): Isolate ‘_socket’ (apply PEP 687(95)).  Patch by
     Erlend E. Aasland.

   - gh-100479(96): Add *note pathlib.PurePath.with_segments(): 4aa,
     which creates a path object from arguments.  This method is called
     whenever a derivative path is created, such as from *note
     pathlib.PurePath.parent: 183d.  Subclasses may override this method
     to share information between path objects.

   - gh-103220(97): Fix issue where *note os.path.join(): 173c. added a
     slash when joining onto an incomplete UNC drive with a trailing
     slash on Windows.

   - gh-103204(98): Fixes *note http.server: 72. accepting HTTP requests
     with HTTP version numbers preceded by ‘+’, or ‘-’, or with
     digit-separating ‘_’ characters.  The length of the version numbers
     is also constrained.

   - gh-75586(99): Fix various Windows-specific issues with
     ‘shutil.which’.

   - gh-103193(100): Improve performance of *note
     inspect.getattr_static(): 497.  Patch by Alex Waygood.

   - gh-103176(101): *note sys._current_exceptions(): 4c5. now returns a
     mapping from thread-id to an exception instance, rather than to a
     ‘(typ, exc, tb)’ tuple.

   - gh-103143(102): Polish the help messages and docstrings of *note
     pdb: a5.

   - gh-103015(103): Add 'entrypoint' keyword-only parameter to *note
     sqlite3.Connection.load_extension(): 4bb, for overriding the SQLite
     extension entry point.  Patch by Erlend E. Aasland.

   - gh-103000(104): Improve performance of *note dataclasses.astuple():
     183e. and *note dataclasses.asdict(): 1836. in cases where the
     contents are common Python types.

   - gh-102953(105): The extraction methods in *note tarfile: de, and
     *note shutil.unpack_archive(): 46e, have a new a 'filter' argument
     that allows limiting tar features than may be surprising or
     dangerous, such as creating files outside the destination
     directory.  See *note Extraction filters: 46f. for details.

   - gh-97696(106): Implemented an eager task factory in asyncio.  When
     used as a task factory on an event loop, it performs eager
     execution of coroutines.  Coroutines that are able to complete
     synchronously (e.g.  return or raise without blocking) are returned
     immediately as a finished task, and the task is never scheduled to
     the event loop.  If the coroutine blocks, the (pending) task is
     scheduled and returned.

   - gh-81079(107): Add 'case_sensitive' keyword-only argument to *note
     pathlib.Path.glob(): 22d. and *note rglob(): 22e.

   - gh-101819(108): Isolate the *note io: 7f. extension module by
     applying PEP 687(109).  Patch by Kumar Aditya, Victor Stinner, and
     Erlend E. Aasland.

   - gh-91896(110): Deprecate *note collections.abc.ByteString: 2e7.

   - gh-101362(111): Speed up *note pathlib.Path: 229. construction by
     omitting the path anchor from the internal list of path parts.

   - gh-102114(112): Functions in the *note dis: 38. module that accept
     a source code string as argument now print a more concise traceback
     when the string contains a syntax or indentation error.

   - gh-62432(113): The *note unittest: 106. runner will now exit with
     status code 5 if no tests were run.  It is common for test runner
     misconfiguration to fail to find any tests, this should be an
     error.

   - gh-78079(114): Fix incorrect normalization of UNC device path
     roots, and partial UNC share path roots, in *note pathlib.PurePath:
     4a9.  Pathlib no longer appends a trailing slash to such paths.

   - gh-85984(115): Add *note tty.cfmakeraw(): 17dc. and *note
     tty.cfmakecbreak(): 178c. to *note tty: 100. and modernize, the
     behavior of *note tty.setraw(): 17db. and *note tty.setcbreak():
     178b. to use POSIX.1-2017 Chapter 11 “General Terminal Interface”
     flag masks by default.

   - gh-101688(116): Implement *note types.get_original_bases(): 4d1. to
     provide further introspection for types.

   - gh-101640(117): *note argparse.ArgumentParser: 53c. now catches
     errors when writing messages, such as when *note sys.stderr: 943.
     is ‘None’.  Patch by Oleg Iarygin.

   - gh-83861(118): Fix datetime.astimezone method return value when
     invoked on a naive datetime instance that represents local time
     falling in a timezone transition gap.  PEP 495 requires that
     instances with fold=1 produce earlier times than those with fold=0
     in this case.

   - gh-89550(119): Decrease execution time of some *note gzip: 67. file
     writes by 15% by adding more appropriate buffering.

   - gh-95299(120): Remove the bundled setuptools wheel from
     ‘ensurepip’, and stop installing setuptools in environments created
     by ‘venv’.

   - gh-99353(121): Respect the *note http.client.HTTPConnection: b59.
     ‘.debuglevel’ flag in ‘urllib.request.AbstractHTTPHandler’ when its
     constructor parameter ‘debuglevel’ is not set.  And do the same for
     ‘*HTTPS*’.

   - gh-98040(122): Remove the long-deprecated ‘imp’ module.

   - gh-97850(123): Deprecate *note pkgutil.find_loader(): 2cb. and
     *note pkgutil.get_loader(): 2cc. in favor of *note
     importlib.util.find_spec(): 2cd.

   - gh-94473(124): Flatten arguments in ‘tkinter.Canvas.coords()’.  It
     now accepts not only ‘x1, y1, x2, y2, ...’ and ‘[x1, y1, x2, y2,
     ...]’, but also ‘(x1, y1), (x2, y2), ...’ and ‘[(x1, y1), (x2, y2),
     ...]’.

   - gh-98040(125): Remove more deprecated importlib APIs:
     ‘find_loader()’, ‘find_module()’, ‘importlib.abc.Finder’,
     ‘pkgutil.ImpImporter’, ‘pkgutil.ImpLoader’.

   - gh-96522(126): Fix potential deadlock in pty.spawn()

   - gh-96534(127): Support divert(4) added in FreeBSD 14.

   - gh-87474(128): Fix potential file descriptor leaks in *note
     subprocess.Popen: 199.

   - gh-94906(129): Support multiple steps in *note math.nextafter():
     49b.  Patch by Shantanu Jain and Matthias Gorgens.

   - gh-51574(130): Make *note tempfile.mkdtemp(): 21f. return absolute
     paths when its 'dir' parameter is relative.

   - gh-94518(131): Convert private ‘_posixsubprocess.fork_exec()’ to
     use Argument Clinic.

   - gh-92184(132): When creating zip files using *note zipfile: 131,
     ‘os.altsep’, if not ‘None’, will always be treated as a path
     separator even when it is not ‘/’.  Patch by Carey Metcalfe.

   - bpo-46797(133): Deprecation warnings are now emitted for ‘ast.Num’,
     ‘ast.Bytes’, ‘ast.Str’, ‘ast.NameConstant’ and ‘ast.Ellipsis’.
     These have been documented as deprecated since Python 3.8, and will
     be removed in Python 3.14.

   - bpo-44844(134): Enables *note webbrowser: 115. to detect and launch
     Microsoft Edge browser.

   - bpo-45606(135): Fixed the bug in *note pathlib.Path.glob(): 22d. –
     previously a dangling symlink would not be found by this method
     when the pattern is an exact match, but would be found when the
     pattern contains a wildcard or the recursive wildcard (‘**’).  With
     this change, a dangling symlink will be found in both cases.

   - bpo-23041(136): Add *note QUOTE_STRINGS: 488. and *note
     QUOTE_NOTNULL: 487. to the suite of *note csv: 29. module quoting
     styles.

   - bpo-24964(137): Added *note
     http.client.HTTPConnection.get_proxy_response_headers(): 1812. that
     provides access to the HTTP headers on a proxy server response to
     the ‘CONNECT’ request.

   - bpo-17258(138): *note multiprocessing: 94. now supports stronger
     HMAC algorithms for inter-process connection authentication rather
     than only HMAC-MD5.

   - bpo-39744(139): Make *note
     asyncio.subprocess.Process.communicate(): 183f. close the
     subprocess’s stdin even when called with ‘input=None’.

   - bpo-22708(140): http.client CONNECT method tunnel improvements: Use
     HTTP 1.1 protocol; send a matching Host: header with CONNECT, if
     one is not provided; convert IDN domain names to Punycode.  Patch
     by Michael Handler.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31821

   (2) https://github.com/python/cpython/issues/104600

   (3) https://peps.python.org/pep-0695/

   (4) https://github.com/python/cpython/issues/104340

   (5) https://github.com/python/cpython/issues/104555

   (6) https://github.com/python/cpython/issues/104372

   (7) https://github.com/python/cpython/issues/104484

   (8) https://github.com/python/cpython/issues/75367

   (9) https://github.com/python/cpython/issues/104536

   (10) https://github.com/python/cpython/issues/103857

   (11) https://github.com/python/cpython/issues/101520

   (12) https://github.com/python/cpython/issues/104392

   (13) https://github.com/python/cpython/issues/102613

   (14) https://github.com/python/cpython/issues/103000

   (15) https://github.com/python/cpython/issues/104301

   (16) https://github.com/python/cpython/issues/104139

   (17) 
https://support.apple.com/en-gb/guide/deployment/depce7cefc4d/web

   (18) https://github.com/python/cpython/issues/104307

   (19) https://github.com/python/cpython/issues/104310

   (20) https://github.com/python/cpython/issues/87695

   (21) https://github.com/python/cpython/issues/104265

   (22) https://bugs.python.org/issue?@action=redirect&bpo=14935

   (23) https://github.com/python/cpython/issues/102613

   (24) https://github.com/python/cpython/issues/65772

   (25) https://github.com/python/cpython/issues/90208

   (26) https://github.com/python/cpython/issues/104144

   (27) https://github.com/python/cpython/issues/104144

   (28) https://github.com/python/cpython/issues/104114

   (29) https://github.com/python/cpython/issues/104104

   (30) https://github.com/python/cpython/issues/104102

   (31) https://github.com/python/cpython/issues/103822

   (32) https://github.com/python/cpython/issues/103629

   (33) https://peps.python.org/pep-0692/

   (34) https://github.com/python/cpython/issues/103963

   (35) https://github.com/python/cpython/issues/104035

   (36) https://github.com/python/cpython/issues/103987

   (37) https://github.com/python/cpython/issues/103977

   (38) https://github.com/python/cpython/issues/88773

   (39) https://github.com/python/cpython/issues/103935

   (40) https://github.com/python/cpython/issues/68968

   (41) https://github.com/python/cpython/issues/100370

   (42) https://github.com/python/cpython/issues/102628

   (43) https://github.com/python/cpython/issues/103636

   (44) https://github.com/python/cpython/issues/103583

   (45) https://github.com/python/cpython/issues/103848

   (46) https://github.com/python/cpython/issues/103872

   (47) https://github.com/python/cpython/issues/99944

   (48) https://github.com/python/cpython/issues/74940

   (49) https://github.com/python/cpython/issues/103861

   (50) https://github.com/python/cpython/issues/103857

   (51) https://github.com/python/cpython/issues/103839

   (52) https://github.com/python/cpython/issues/103791

   (53) https://github.com/python/cpython/issues/90750

   (54) https://github.com/python/cpython/issues/103685

   (55) https://github.com/python/cpython/issues/81403

   (56) https://github.com/python/cpython/issues/103699

   (57) https://github.com/python/cpython/issues/103693

   (58) https://github.com/python/cpython/issues/92248

   (59) https://github.com/python/cpython/issues/89415

   (60) https://github.com/python/cpython/issues/103673

   (61) https://github.com/python/cpython/issues/103636

   (62) https://github.com/python/cpython/issues/84976

   (63) https://github.com/python/cpython/issues/103596

   (64) https://github.com/python/cpython/issues/103584

   (65) https://github.com/python/cpython/issues/103578

   (66) https://github.com/python/cpython/issues/103556

   (67) https://github.com/python/cpython/issues/103559

   (68) https://github.com/python/cpython/issues/103548

   (69) https://github.com/python/cpython/issues/103538

   (70) https://github.com/python/cpython/issues/103533

   (71) https://github.com/python/cpython/issues/103525

   (72) https://github.com/python/cpython/issues/103489

   (73) https://github.com/python/cpython/issues/103365

   (74) https://github.com/python/cpython/issues/103472

   (75) https://github.com/python/cpython/issues/103462

   (76) https://github.com/python/cpython/issues/103449

   (77) https://github.com/python/cpython/issues/103092

   (78) https://peps.python.org/pep-0687/

   (79) https://github.com/python/cpython/issues/103357

   (80) https://github.com/python/cpython/issues/103092

   (81) https://peps.python.org/pep-0687/

   (82) https://github.com/python/cpython/issues/74690

   (83) https://github.com/python/cpython/issues/74690

   (84) https://github.com/python/cpython/issues/103256

   (85) https://github.com/python/cpython/issues/102778

   (86) https://github.com/python/cpython/issues/103285

   (87) https://github.com/python/cpython/issues/103225

   (88) https://github.com/python/cpython/issues/103092

   (89) https://peps.python.org/pep-0687/

   (90) https://github.com/python/cpython/issues/103092

   (91) https://peps.python.org/pep-0687/

   (92) https://github.com/python/cpython/issues/93910

   (93) https://github.com/python/cpython/issues/102978

   (94) https://github.com/python/cpython/issues/103092

   (95) https://peps.python.org/pep-0687/

   (96) https://github.com/python/cpython/issues/100479

   (97) https://github.com/python/cpython/issues/103220

   (98) https://github.com/python/cpython/issues/103204

   (99) https://github.com/python/cpython/issues/75586

   (100) https://github.com/python/cpython/issues/103193

   (101) https://github.com/python/cpython/issues/103176

   (102) https://github.com/python/cpython/issues/103143

   (103) https://github.com/python/cpython/issues/103015

   (104) https://github.com/python/cpython/issues/103000

   (105) https://github.com/python/cpython/issues/102953

   (106) https://github.com/python/cpython/issues/97696

   (107) https://github.com/python/cpython/issues/81079

   (108) https://github.com/python/cpython/issues/101819

   (109) https://peps.python.org/pep-0687/

   (110) https://github.com/python/cpython/issues/91896

   (111) https://github.com/python/cpython/issues/101362

   (112) https://github.com/python/cpython/issues/102114

   (113) https://github.com/python/cpython/issues/62432

   (114) https://github.com/python/cpython/issues/78079

   (115) https://github.com/python/cpython/issues/85984

   (116) https://github.com/python/cpython/issues/101688

   (117) https://github.com/python/cpython/issues/101640

   (118) https://github.com/python/cpython/issues/83861

   (119) https://github.com/python/cpython/issues/89550

   (120) https://github.com/python/cpython/issues/95299

   (121) https://github.com/python/cpython/issues/99353

   (122) https://github.com/python/cpython/issues/98040

   (123) https://github.com/python/cpython/issues/97850

   (124) https://github.com/python/cpython/issues/94473

   (125) https://github.com/python/cpython/issues/98040

   (126) https://github.com/python/cpython/issues/96522

   (127) https://github.com/python/cpython/issues/96534

   (128) https://github.com/python/cpython/issues/87474

   (129) https://github.com/python/cpython/issues/94906

   (130) https://github.com/python/cpython/issues/51574

   (131) https://github.com/python/cpython/issues/94518

   (132) https://github.com/python/cpython/issues/92184

   (133) https://bugs.python.org/issue?@action=redirect&bpo=46797

   (134) https://bugs.python.org/issue?@action=redirect&bpo=44844

   (135) https://bugs.python.org/issue?@action=redirect&bpo=45606

   (136) https://bugs.python.org/issue?@action=redirect&bpo=23041

   (137) https://bugs.python.org/issue?@action=redirect&bpo=24964

   (138) https://bugs.python.org/issue?@action=redirect&bpo=17258

   (139) https://bugs.python.org/issue?@action=redirect&bpo=39744

   (140) https://bugs.python.org/issue?@action=redirect&bpo=22708


File: python.info,  Node: Documentation<19>,  Next: Tests<22>,  Prev: Library<43>,  Up: Python 3 12 0 beta 1

1.23.28.9 Documentation
.......................

   - gh-67056(1): Document that the effect of registering or
     unregistering an *note atexit: c. cleanup function from within a
     registered cleanup function is undefined.

   - gh-103629(2): Mention the new way of typing ‘**kwargs’ with
     ‘Unpack’ and ‘TypedDict’ introduced in PEP 692(3).

   - gh-48241(4): Clarifying documentation about the url parameter to
     urllib.request.urlopen and urllib.request.Request needing to be
     encoded properly.

   - gh-86094(5): Add support for Unicode Path Extra Field in ZipFile.
     Patch by Yeojin Kim and Andrea Giudiceandrea

   - gh-99202(6): Fix extension type from documentation for compiling in
     C++20 mode

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/67056

   (2) https://github.com/python/cpython/issues/103629

   (3) https://peps.python.org/pep-0692/

   (4) https://github.com/python/cpython/issues/48241

   (5) https://github.com/python/cpython/issues/86094

   (6) https://github.com/python/cpython/issues/99202


File: python.info,  Node: Tests<22>,  Next: Build<22>,  Prev: Documentation<19>,  Up: Python 3 12 0 beta 1

1.23.28.10 Tests
................

   - gh-104494(1): Update ‘test_pack_configure_in’ and
     ‘test_place_configure_in’ for changes to error message formatting
     in Tk 8.7.

   - gh-104461(2): Run test_configure_screen on X11 only, since the
     ‘DISPLAY’ environment variable and ‘-screen’ option for toplevels
     are not useful on Tk for Win32 or Aqua.

   - gh-86275(3): Added property-based tests to the *note zoneinfo: 134.
     tests, along with stubs for the ‘hypothesis’ interface.  (Patch by
     Paul Ganssle)

   - gh-103329(4): Regression tests for the behaviour of
     ‘unittest.mock.PropertyMock’ were added.

   - gh-102795(5): fix use of poll in test_epoll’s test_control_and_wait

   - gh-75729(6): Fix the *note os.spawn*: 1842. tests failing on
     Windows when the working directory or interpreter path contains
     spaces.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104494

   (2) https://github.com/python/cpython/issues/104461

   (3) https://github.com/python/cpython/issues/86275

   (4) https://github.com/python/cpython/issues/103329

   (5) https://github.com/python/cpython/issues/102795

   (6) https://github.com/python/cpython/issues/75729


File: python.info,  Node: Build<22>,  Next: Windows<20>,  Prev: Tests<22>,  Up: Python 3 12 0 beta 1

1.23.28.11 Build
................

   - gh-101282(1): BOLT optimization is now applied to the libpython
     shared library if building a shared library.  BOLT instrumentation
     and application settings can now be influenced via the
     ‘BOLT_INSTRUMENT_FLAGS’ and ‘BOLT_APPLY_FLAGS’ configure variables.

   - gh-99017(2): ‘PYTHON_FOR_REGEN’ now require Python 3.10 or newer.

   - gh-104490(3): Define ‘.PHONY’ / virtual make targets consistently
     and properly.

   - gh-104106(4): Add gcc fallback of mkfifoat/mknodat for macOS. Patch
     by Donghee Na.

   - gh-103532(5): The ‘TKINTER_PROTECT_LOADTK’ macro is no longer
     defined or used in the ‘_tkinter’ module.  It was previously only
     defined when building against Tk 8.4.13 and older, but Tk older
     than 8.5.12 has been unsupported since gh-91152(6).

   - gh-99069(7): Extended workaround defining ‘static_assert’ when
     missing from the libc headers to all clang and gcc builds.  In
     particular, this fixes building on macOS <= 10.10.

   - gh-100220(8): Changed the default value of the ‘SHELL’ Makefile
     variable from ‘/bin/sh’ to ‘/bin/sh -e’ to ensure that complex
     recipes correctly fail after an error.  Previously, ‘make install’
     could fail to install some files and yet return a successful
     result.

   - gh-90656(9): Add platform triplets for 64-bit LoongArch:

        * loongarch64-linux-gnusf

        * loongarch64-linux-gnuf32

        * loongarch64-linux-gnu

     Patch by Zhang Na.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101282

   (2) https://github.com/python/cpython/issues/99017

   (3) https://github.com/python/cpython/issues/104490

   (4) https://github.com/python/cpython/issues/104106

   (5) https://github.com/python/cpython/issues/103532

   (6) https://github.com/python/cpython/issues/91152

   (7) https://github.com/python/cpython/issues/99069

   (8) https://github.com/python/cpython/issues/100220

   (9) https://github.com/python/cpython/issues/90656


File: python.info,  Node: Windows<20>,  Next: macOS<15>,  Prev: Build<22>,  Up: Python 3 12 0 beta 1

1.23.28.12 Windows
..................

   - gh-104623(1): Update Windows installer to use SQLite 3.42.0.

   - gh-82814(2): Fix a potential ‘[Errno 13] Permission denied’ when
     using *note shutil.copystat(): 1172. within Windows Subsystem for
     Linux (WSL) on a mounted filesystem by adding ‘errno.EACCES’ to the
     list of ignored errors within the internal implementation.

   - gh-103088(3): Fix virtual environment ‘activate’ script having
     incorrect line endings for Cygwin.

   - gh-103088(4): Fixes venvs not working in bash on Windows across
     different disks

   - gh-102997(5): Update Windows installer to use SQLite 3.41.2.

   - gh-88013(6): Fixed a bug where *note TypeError: 2c3. was raised
     when calling ‘ntpath.realpath()’ with a bytes parameter in some
     cases.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104623

   (2) https://github.com/python/cpython/issues/82814

   (3) https://github.com/python/cpython/issues/103088

   (4) https://github.com/python/cpython/issues/103088

   (5) https://github.com/python/cpython/issues/102997

   (6) https://github.com/python/cpython/issues/88013


File: python.info,  Node: macOS<15>,  Next: IDLE<18>,  Prev: Windows<20>,  Up: Python 3 12 0 beta 1

1.23.28.13 macOS
................

   - gh-99834(1): Update macOS installer to Tcl/Tk 8.6.13.

   - gh-104623(2): Update macOS installer to SQLite 3.42.0.

   - gh-103545(3): Add ‘os.PRIO_DARWIN_THREAD’,
     ‘os.PRIO_DARWIN_PROCESS’, ‘os.PRIO_DARWIN_BG’ and
     ‘os.PRIO_DARWIN_NONUI’.  These can be used with ‘os.setpriority’ to
     run the process at a lower priority and make use of the efficiency
     cores on Apple Silicon systems.

   - gh-104180(4): Support reading SOCKS proxy configuration from macOS
     System Configuration.  Patch by Sam Schott.

   - gh-60436(5): update curses textbox to additionally handle backspace
     using the ‘curses.ascii.DEL’ key press.

   - gh-102997(6): Update macOS installer to SQLite 3.41.2.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99834

   (2) https://github.com/python/cpython/issues/104623

   (3) https://github.com/python/cpython/issues/103545

   (4) https://github.com/python/cpython/issues/104180

   (5) https://github.com/python/cpython/issues/60436

   (6) https://github.com/python/cpython/issues/102997


File: python.info,  Node: IDLE<18>,  Next: Tools/Demos<13>,  Prev: macOS<15>,  Up: Python 3 12 0 beta 1

1.23.28.14 IDLE
...............

   - gh-104499(1): Fix completions for Tk Aqua 8.7 (currently blank).

   - gh-104496(2): About prints both tcl and tk versions if different
     (expected someday).

   - gh-88496(3): Fix IDLE test hang on macOS.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104499

   (2) https://github.com/python/cpython/issues/104496

   (3) https://github.com/python/cpython/issues/88496


File: python.info,  Node: Tools/Demos<13>,  Next: C API<22>,  Prev: IDLE<18>,  Up: Python 3 12 0 beta 1

1.23.28.15 Tools/Demos
......................

   - gh-104389(1): Argument Clinic C converters now accept the ‘unused’
     keyword, for wrapping a parameter with *note Py_UNUSED: 1829.
     Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/104389


File: python.info,  Node: C API<22>,  Prev: Tools/Demos<13>,  Up: Python 3 12 0 beta 1

1.23.28.16 C API
................

   - gh-101291(1): Added unstable C API for extracting the value of
     “compact” integers: *note PyUnstable_Long_IsCompact(): 58c. and
     *note PyUnstable_Long_CompactValue(): 58d.

   - gh-104109(2): We’ve added ‘Py_NewInterpreterFromConfig()’ and
     ‘PyInterpreterConfig’ to the public C-API (but not the stable ABI;
     not yet at least).  The new function may be used to create a new
     interpreter with various features configured.  The function was
     added to support PEP 684 (per-interpreter GIL).

   - gh-103968(3): *note PyType_FromSpec(): 580. and its variants now
     allow creating classes whose metaclass overrides *note tp_new: 582.
     The ‘tp_new’ is ignored.  This behavior is deprecated and will be
     disallowed in 3.14+.  The new *note PyType_FromMetaclass(): 553.
     already disallows it.

   - gh-103743(4): Add *note PyUnstable_Object_GC_NewWithExtraData():
     1849. function that can be used to allocate additional memory after
     an object for data not managed by Python.

   - gh-103295(5): Introduced *note PyUnstable_WritePerfMapEntry():
     184a, *note PyUnstable_PerfMapState_Init(): 184b. and *note
     PyUnstable_PerfMapState_Fini(): 184c.  These allow extension
     modules (JIT compilers in particular) to write to perf-map files in
     a thread safe manner.  The *note Python support for the Linux perf
     profiler: 184d. also uses these APIs to write entries in the
     perf-map file.

   - gh-103509(6): Added C API for extending types whose instance memory
     layout is opaque: *note PyType_Spec.basicsize: 54b. can now be zero
     or negative, *note PyObject_GetTypeData(): 54c. can be used to get
     subclass-specific data, and *note Py_TPFLAGS_ITEMS_AT_END: 54e. can
     be used to safely extend variable-size objects.  See PEP 697(7) for
     details.

   - gh-103091(8): Add a new C-API function to eagerly assign a version
     tag to a PyTypeObject: ‘PyUnstable_Type_AssignVersionTag()’.

   - gh-101408(9): *note PyObject_GC_Resize: 184e. should calculate
     preheader size if needed.  Patch by Donghee Na.

   - gh-98836(10): Add support of more formatting options (left
     aligning, octals, uppercase hexadecimals, ‘intmax_t’, ‘ptrdiff_t’,
     ‘wchar_t’ C strings, variable width and precision) in *note
     PyUnicode_FromFormat(): 38d. and *note PyUnicode_FromFormatV():
     577.

   - gh-96803(11): Add unstable C-API functions to get the code object,
     lasti and line number from the internal ‘_PyInterpreterFrame’ in
     the limited API. The functions are:

        * ‘PyCodeObject * PyUnstable_InterpreterFrame_GetCode(struct
          _PyInterpreterFrame *frame)’

        * ‘int PyUnstable_InterpreterFrame_GetLasti(struct
          _PyInterpreterFrame *frame)’

        * ‘int PyUnstable_InterpreterFrame_GetLine(struct
          _PyInterpreterFrame *frame)’

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101291

   (2) https://github.com/python/cpython/issues/104109

   (3) https://github.com/python/cpython/issues/103968

   (4) https://github.com/python/cpython/issues/103743

   (5) https://github.com/python/cpython/issues/103295

   (6) https://github.com/python/cpython/issues/103509

   (7) https://peps.python.org/pep-0697/

   (8) https://github.com/python/cpython/issues/103091

   (9) https://github.com/python/cpython/issues/101408

   (10) https://github.com/python/cpython/issues/98836

   (11) https://github.com/python/cpython/issues/96803


File: python.info,  Node: Python 3 12 0 alpha 7,  Next: Python 3 12 0 alpha 6,  Prev: Python 3 12 0 beta 1,  Up: Changelog

1.23.29 Python 3.12.0 alpha 7
-----------------------------

'Release date: 2023-04-04'

* Menu:

* Core and Builtins: Core and Builtins<39>.
* Library: Library<44>.
* Core and Builtins: Core and Builtins<40>.
* Build: Build<23>.
* Core and Builtins: Core and Builtins<41>.
* Library: Library<45>.
* Documentation: Documentation<20>.
* Tests: Tests<23>.
* Build: Build<24>.
* Windows: Windows<21>.
* Tools/Demos: Tools/Demos<14>.
* C API: C API<23>.


File: python.info,  Node: Core and Builtins<39>,  Next: Library<44>,  Up: Python 3 12 0 alpha 7

1.23.29.1 Core and Builtins
...........................

   - gh-102192(1): Deprecated ‘_PyErr_ChainExceptions’ in favour of
     ‘_PyErr_ChainExceptions1’.

   - gh-89987(2): Reduce the number of inline *note CACHE: 6fc. entries
     for *note BINARY_SUBSCR: 1851.

   - gh-102859(3): Removed ‘JUMP_IF_FALSE_OR_POP’ and
     ‘JUMP_IF_TRUE_OR_POP’ instructions.

   - gh-101975(4): Fixed ‘stacktop’ value on tracing entries to avoid
     corruption on garbage collection.

   - gh-102778(5): Add *note sys.last_exc: 4c1. and deprecate *note
     sys.last_type: 4c2, *note sys.last_value: 4c3. and *note
     sys.last_traceback: 4c4, which hold the same information in its
     legacy form.

   - gh-100982(6): Replace all occurrences of ‘COMPARE_AND_BRANCH’ with
     *note COMPARE_OP: 973.

   - gh-102701(7): Fix overflow when creating very large dict.

   - gh-102755(8): Add *note PyErr_DisplayException(): 405. which takes
     just an exception instance, to replace the legacy ‘PyErr_Display()’
     which takes the ‘(typ, exc, tb)’ triplet.

   - gh-102594(9): Add note to exception raised in ‘PyErr_SetObject’
     when normalization fails.

   - gh-90997(10): Shrink the number of inline *note CACHE: 6fc. entries
     used by *note LOAD_GLOBAL: 17f9.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102192

   (2) https://github.com/python/cpython/issues/89987

   (3) https://github.com/python/cpython/issues/102859

   (4) https://github.com/python/cpython/issues/101975

   (5) https://github.com/python/cpython/issues/102778

   (6) https://github.com/python/cpython/issues/100982

   (7) https://github.com/python/cpython/issues/102701

   (8) https://github.com/python/cpython/issues/102755

   (9) https://github.com/python/cpython/issues/102594

   (10) https://github.com/python/cpython/issues/90997


File: python.info,  Node: Library<44>,  Next: Core and Builtins<40>,  Prev: Core and Builtins<39>,  Up: Python 3 12 0 alpha 7

1.23.29.2 Library
.................

   - gh-102491(1): Improve import time of ‘platform’ by removing
     IronPython version parsing.  The IronPython version parsing was not
     functional (see
     ‘https://github.com/IronLanguages/ironpython3/issues/1667’).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102491


File: python.info,  Node: Core and Builtins<40>,  Next: Build<23>,  Prev: Library<44>,  Up: Python 3 12 0 alpha 7

1.23.29.3 Core and Builtins
...........................

   - gh-101291(1): Rearrage bits in first field (after header) of
     PyLongObject.  * Bits 0 and 1: 1 - sign.  I.e.  0 for positive
     numbers, 1 for zero and 2 for negative numbers.  * Bit 2 reserved
     (probably for the immortal bit) * Bits 3+ the unsigned size.

     This makes a few operations slightly more efficient, and will
     enable a more compact and faster 2s-complement representation of
     most ints in future.

   - gh-102397(2): Fix segfault from race condition in signal handling
     during garbage collection.  Patch by Kumar Aditya.

   - gh-102406(3): *note codecs: 1b. encoding/decoding errors now get
     the context information (which operation and which codecs) attached
     as PEP 678(4) notes instead of through chaining a new instance of
     the exception.

   - gh-102281(5): Fix potential nullptr dereference and use of
     uninitialized memory in fileutils.  Patch by Max Bachmann.

   - gh-102300(6): Reuse operands with refcount of 1 in float
     specializations of BINARY_OP.

   - gh-102213(7): Fix performance loss when accessing an object’s
     attributes with ‘__getattr__’ defined.

   - gh-102255(8): Improve build support for the Xbox.  Patch by Max
     Bachmann.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101291

   (2) https://github.com/python/cpython/issues/102397

   (3) https://github.com/python/cpython/issues/102406

   (4) https://peps.python.org/pep-0678/

   (5) https://github.com/python/cpython/issues/102281

   (6) https://github.com/python/cpython/issues/102300

   (7) https://github.com/python/cpython/issues/102213

   (8) https://github.com/python/cpython/issues/102255


File: python.info,  Node: Build<23>,  Next: Core and Builtins<41>,  Prev: Core and Builtins<40>,  Up: Python 3 12 0 alpha 7

1.23.29.4 Build
...............

   - gh-102027(1): Fix SSE2 and SSE3 detection in ‘_blake2’ internal
     module.  Patch by Max Bachmann.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102027


File: python.info,  Node: Core and Builtins<41>,  Next: Library<45>,  Prev: Build<23>,  Up: Python 3 12 0 alpha 7

1.23.29.5 Core and Builtins
...........................

   - gh-101865(1): Deprecate ‘co_lnotab’ in code objects, schedule it
     for removal in Python 3.14

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101865


File: python.info,  Node: Library<45>,  Next: Documentation<20>,  Prev: Core and Builtins<41>,  Up: Python 3 12 0 alpha 7

1.23.29.6 Library
.................

   - bpo-1635741(1): Adapt ‘_pickle’ to PEP 687(2).  Patch by Mohamed
     Koubaa and Erlend Aasland.

   - gh-103085(3): Pure python *note locale.getencoding(): 2dc. will not
     warn deprecation.

   - gh-103068(4): It’s no longer possible to register conditional
     breakpoints in *note Pdb: 92b. that raise *note SyntaxError: 18d.
     Patch by Tian Gao.

   - gh-102549(5): Don’t ignore exceptions in member type creation.

   - gh-103056(6): Ensure final ‘_generate_next_value_’ is a
     ‘staticmethod’.

   - gh-103046(7): Display current line label correctly in *note dis:
     38. when ‘show_caches’ is False and ‘lasti’ points to a CACHE
     entry.

   - gh-102433(8): *note isinstance(): 445. checks against *note
     runtime-checkable protocols: 446. now use *note
     inspect.getattr_static(): 497. rather than *note hasattr(): 4d5. to
     lookup whether attributes exist.  This means that descriptors and
     *note __getattr__(): 4d6. methods are no longer unexpectedly
     evaluated during ‘isinstance()’ checks against runtime-checkable
     protocols.  However, it may also mean that some objects which used
     to be considered instances of a runtime-checkable protocol may no
     longer be considered instances of that protocol on Python 3.12+,
     and vice versa.  Most users are unlikely to be affected by this
     change.  Patch by Alex Waygood.

   - gh-103023(9): It’s no longer possible to register expressions to
     display in *note Pdb: 92b. that raise *note SyntaxError: 18d.
     Patch by Tian Gao.

   - gh-102947(10): Improve traceback when *note dataclasses.fields():
     1857. is called on a non-dataclass.  Patch by Alex Waygood

   - gh-102780(11): The *note asyncio.Timeout: 17da. context manager now
     works reliably even when performing cleanup due to task
     cancellation.  Previously it could raise a *note CancelledError:
     1b8. instead of an *note TimeoutError: 1858. in such cases.

   - gh-102871(12): Remove support for obsolete browsers from *note
     webbrowser: 115.  Removed browsers include Grail, Mosaic, Netscape,
     Galeon, Skipstone, Iceape, Firebird, and Firefox versions 35 and
     below.

   - gh-102839(13): Improve performance of *note math.log(): 150f.
     arguments handling by removing the argument clinic.

   - gh-102828(14): Add the ‘onexc’ arg to *note shutil.rmtree(): 301,
     which is like ‘onerror’ but expects an exception instance rather
     than an exc_info tuple.  Deprecate ‘onerror’.

   - gh-88965(15): typing: Fix a bug relating to substitution in custom
     classes generic over a *note ParamSpec: 15e.  Previously, if the
     ‘ParamSpec’ was substituted with a parameters list that itself
     contained a *note TypeVar: 15d, the ‘TypeVar’ in the parameters
     list could not be subsequently substituted.  This is now fixed.

     Patch by Nikita Sobolev.

   - gh-76846(16): Fix issue where ‘__new__()’ and ‘__init__()’ methods
     of *note pathlib.PurePath: 4a9. and *note Path: 229. subclasses
     were not called in some circumstances.

   - gh-78530(17): *note asyncio.wait(): 482. now accepts generators
     yielding tasks.  Patch by Kumar Aditya.

   - gh-102748(18): *note asyncio.iscoroutine(): 481. now returns
     ‘False’ for generators as *note asyncio: a. does not support legacy
     generator-based coroutines.  Patch by Kumar Aditya.

   - gh-102670(19): Optimized fmean(), correlation(), covariance(), and
     linear_regression() using the new math.sumprod() function.

   - gh-102615(20): Typing: Improve the ‘repr’ of generic aliases for
     classes generic over a *note ParamSpec: 15e.  (Use square brackets
     to represent a parameter list.)

   - gh-100112(21): *note asyncio.Task.get_coro(): 9e7. now always
     returns a coroutine when wrapping an awaitable object.  Patch by
     Kumar Aditya.

   - gh-102578(22): Speed up setting or deleting mutable attributes on
     non-dataclass subclasses of frozen dataclasses.  Due to the
     implementation of ‘__setattr__’ and ‘__delattr__’ for frozen
     dataclasses, this previously had a time complexity of 'O'('n').  It
     now has a time complexity of 'O'(1).

   - gh-102519(23): Add *note os.listdrives(): 4a0, *note
     os.listvolumes(): 4a1. and *note os.listmounts(): 4a2. functions on
     Windows for enumerating drives, volumes and mount points

   - gh-74468(24): Attribute name of the extracted *note tarfile: de.
     file object now holds filename of itself rather than of the archive
     it is contained in.  Patch by Oleg Iarygin.

   - gh-102378(25): Private helper method
     ‘inspect._signature_strip_non_python_syntax’ will no longer strip
     ‘/’ from the input string.

   - gh-79940(26): Add *note inspect.getasyncgenstate(): 495. and *note
     inspect.getasyncgenlocals(): 496.  Patch by Thomas Krennwallner.

   - gh-102103(27): Add ‘module’ argument to *note
     dataclasses.make_dataclass(): 1859. and make classes produced by it
     pickleable.

   - gh-102069(28): Fix ‘__weakref__’ descriptor generation for custom
     dataclasses.

   - gh-102038(29): Skip a ‘stat’ in *note site: c7. if we have already
     found a ‘pyvenv.cfg’

   - gh-98886(30): Fix issues when defining dataclasses that have fields
     with specific underscore names that aren’t clearly reserved by
     *note dataclasses: 2f.

   - gh-101673(31): Fix a *note pdb: a5. bug where ‘ll’ clears the
     changes to local variables.

   - gh-101313(32): Added -h and –help arguments to the webbrowser CLI

   - gh-100372(33): *note ssl.SSLContext.load_verify_locations(): f22.
     no longer incorrectly accepts some cases of trailing data when
     parsing DER.

   - gh-89727(34): Fix pathlib.Path.walk RecursionError on deep
     directory trees by rewriting it using iteration instead of
     recursion.

   - gh-100131(35): Added an optional ‘delete’ keyword argument to *note
     tempfile.TemporaryDirectory: 127a.

   - gh-48330(36): Added ‘--durations’ command line option, showing the
     N slowest test cases.  *note unittest.TextTestRunner: 185a. and
     *note unittest.TextTestResult: 534. constructors accept a new
     'durations' keyword argument.  Subclasses should take this into
     account or accept ‘**kwargs’.  Added *note
     unittest.TestResult.addDuration(): 185b. method and *note
     unittest.TestResult.collectedDurations: 181b. attribute.

     (Contributed by Giampaolo Rodola)

   - gh-98169(37): Fix *note dataclasses.astuple(): 183e. crash when
     *note collections.defaultdict: 1201. is present in the attributes.

   - gh-96931(38): Fix incorrect results from *note
     ssl.SSLSocket.shared_ciphers(): ea0.

   - gh-95495(39): When built against OpenSSL 3.0, the *note ssl: d0.
     module had a bug where it reported unauthenticated EOFs (i.e.
     without close_notify) as a clean TLS-level EOF. It now raises *note
     SSLEOFError: 185c, matching the behavior in previous versions of
     OpenSSL. The *note options: 83e. attribute on *note SSLContext:
     294. also no longer includes *note OP_IGNORE_UNEXPECTED_EOF: 83d.
     by default.  This option may be set to specify the previous OpenSSL
     3.0 behavior.

   - gh-94684(40): Now *note uuid.uuid3(): 1664. and *note uuid.uuid5():
     1666. functions support *note bytes: 1c2. objects as their 'name'
     argument.

   - gh-94440(41): Fix a ‘concurrent.futures.process’ bug where
     ‘ProcessPoolExecutor’ shutdown could hang after a future has been
     quickly submitted and canceled.

   - gh-72346(42): Added deprecation warning to 'isdst' parameter of
     *note email.utils.localtime(): 2c4.

   - bpo-36305(43): Fix handling of Windows filenames that resemble
     drives, such as ‘./a:b’, in *note pathlib: a4.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0687/

   (3) https://github.com/python/cpython/issues/103085

   (4) https://github.com/python/cpython/issues/103068

   (5) https://github.com/python/cpython/issues/102549

   (6) https://github.com/python/cpython/issues/103056

   (7) https://github.com/python/cpython/issues/103046

   (8) https://github.com/python/cpython/issues/102433

   (9) https://github.com/python/cpython/issues/103023

   (10) https://github.com/python/cpython/issues/102947

   (11) https://github.com/python/cpython/issues/102780

   (12) https://github.com/python/cpython/issues/102871

   (13) https://github.com/python/cpython/issues/102839

   (14) https://github.com/python/cpython/issues/102828

   (15) https://github.com/python/cpython/issues/88965

   (16) https://github.com/python/cpython/issues/76846

   (17) https://github.com/python/cpython/issues/78530

   (18) https://github.com/python/cpython/issues/102748

   (19) https://github.com/python/cpython/issues/102670

   (20) https://github.com/python/cpython/issues/102615

   (21) https://github.com/python/cpython/issues/100112

   (22) https://github.com/python/cpython/issues/102578

   (23) https://github.com/python/cpython/issues/102519

   (24) https://github.com/python/cpython/issues/74468

   (25) https://github.com/python/cpython/issues/102378

   (26) https://github.com/python/cpython/issues/79940

   (27) https://github.com/python/cpython/issues/102103

   (28) https://github.com/python/cpython/issues/102069

   (29) https://github.com/python/cpython/issues/102038

   (30) https://github.com/python/cpython/issues/98886

   (31) https://github.com/python/cpython/issues/101673

   (32) https://github.com/python/cpython/issues/101313

   (33) https://github.com/python/cpython/issues/100372

   (34) https://github.com/python/cpython/issues/89727

   (35) https://github.com/python/cpython/issues/100131

   (36) https://github.com/python/cpython/issues/48330

   (37) https://github.com/python/cpython/issues/98169

   (38) https://github.com/python/cpython/issues/96931

   (39) https://github.com/python/cpython/issues/95495

   (40) https://github.com/python/cpython/issues/94684

   (41) https://github.com/python/cpython/issues/94440

   (42) https://github.com/python/cpython/issues/72346

   (43) https://bugs.python.org/issue?@action=redirect&bpo=36305


File: python.info,  Node: Documentation<20>,  Next: Tests<23>,  Prev: Library<45>,  Up: Python 3 12 0 alpha 7

1.23.29.7 Documentation
.......................

   - gh-103112(1): Add docstring to *note
     http.client.HTTPResponse.read(): 1688. to fix ‘pydoc’ output.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/103112


File: python.info,  Node: Tests<23>,  Next: Build<24>,  Prev: Documentation<20>,  Up: Python 3 12 0 alpha 7

1.23.29.8 Tests
...............

   - gh-102980(1): Improve test coverage on *note pdb: a5.

   - gh-102537(2): Adjust the error handling strategy in
     ‘test_zoneinfo.TzPathTest.python_tzpath_context’.  Patch by Paul
     Ganssle.

   - gh-101377(3): Improved test_locale_calendar_formatweekday of
     calendar.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102980

   (2) https://github.com/python/cpython/issues/102537

   (3) https://github.com/python/cpython/issues/101377


File: python.info,  Node: Build<24>,  Next: Windows<21>,  Prev: Tests<23>,  Up: Python 3 12 0 alpha 7

1.23.29.9 Build
...............

   - gh-102973(1): Add a dev container (along with accompanying
     Dockerfile) for development purposes.

   - gh-102711(2): Fix ‘-Wstrict-prototypes’ compiler warnings.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102973

   (2) https://github.com/python/cpython/issues/102711


File: python.info,  Node: Windows<21>,  Next: Tools/Demos<14>,  Prev: Build<24>,  Up: Python 3 12 0 alpha 7

1.23.29.10 Windows
..................

   - gh-102690(1): Update *note webbrowser: 115. to fall back to
     Microsoft Edge instead of Internet Explorer.

   - gh-99726(2): Improves correctness of stat results for Windows, and
     uses faster API when available

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102690

   (2) https://github.com/python/cpython/issues/99726


File: python.info,  Node: Tools/Demos<14>,  Next: C API<23>,  Prev: Windows<21>,  Up: Python 3 12 0 alpha 7

1.23.29.11 Tools/Demos
......................

   - gh-102809(1): ‘Misc/gdbinit’ was removed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102809


File: python.info,  Node: C API<23>,  Prev: Tools/Demos<14>,  Up: Python 3 12 0 alpha 7

1.23.29.12 C API
................

   - gh-102013(1): Add a new (unstable) C-API function for iterating
     over GC’able objects using a callback: ‘PyUnstable_VisitObjects’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102013


File: python.info,  Node: Python 3 12 0 alpha 6,  Next: Python 3 12 0 alpha 5,  Prev: Python 3 12 0 alpha 7,  Up: Changelog

1.23.30 Python 3.12.0 alpha 6
-----------------------------

'Release date: 2023-03-07'

* Menu:

* Security: Security<20>.
* Core and Builtins: Core and Builtins<42>.
* Library: Library<46>.
* Documentation: Documentation<21>.
* Tests: Tests<24>.
* Build: Build<25>.
* Windows: Windows<22>.
* macOS: macOS<16>.
* C API: C API<24>.


File: python.info,  Node: Security<20>,  Next: Core and Builtins<42>,  Up: Python 3 12 0 alpha 6

1.23.30.1 Security
..................

   - gh-99108(1): Replace builtin hashlib implementations of MD5 and
     SHA1 with verified ones from the HACL* project.

   - gh-101727(2): Updated the OpenSSL version used in Windows and macOS
     binary release builds to 1.1.1t to address CVE 2023-0286(3), CVE
     2022-4303(4), and CVE 2022-4303(5) per the OpenSSL 2023-02-07
     security advisory(6).

   - gh-99108(7): Replace the builtin *note hashlib: 68. implementations
     of SHA2-384 and SHA2-512 originally from LibTomCrypt with formally
     verified, side-channel resistant code from the HACL*(8) project.
     The builtins remain a fallback only used when OpenSSL does not
     provide them.

   - gh-101283(9): *note subprocess.Popen: 199. now uses a safer
     approach to find ‘cmd.exe’ when launching with ‘shell=True’.  Patch
     by Eryk Sun, based on a patch by Oleg Iarygin.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99108

   (2) https://github.com/python/cpython/issues/101727

   (3) https://www.cve.org/CVERecord?id=CVE-2023-0286

   (4) https://www.cve.org/CVERecord?id=CVE-2022-4303

   (5) https://www.cve.org/CVERecord?id=CVE-2022-4303

   (6) https://openssl-library.org/news/secadv/20230207.txt

   (7) https://github.com/python/cpython/issues/99108

   (8) https://github.com/hacl-star/hacl-star/

   (9) https://github.com/python/cpython/issues/101283


File: python.info,  Node: Core and Builtins<42>,  Next: Library<46>,  Prev: Security<20>,  Up: Python 3 12 0 alpha 6

1.23.30.2 Core and Builtins
...........................

   - gh-102493(1): Fix regression in semantics of normalisation in
     ‘PyErr_SetObject’.

   - gh-102416(2): Do not memoize incorrectly automatically generated
     loop rules in the parser.  Patch by Pablo Galindo.

   - gh-102356(3): Fix a bug that caused a crash when deallocating
     deeply nested filter objects.  Patch by Marta Gómez Macías.

   - gh-102336(4): Cleanup Windows 7 specific special handling.  Patch
     by Max Bachmann.

   - gh-102250(5): Fixed a segfault occurring when the interpreter calls
     a ‘__bool__’ method that raises.

   - gh-102126(6): Fix deadlock at shutdown when clearing thread states
     if any finalizer tries to acquire the runtime head lock.  Patch by
     Kumar Aditya.

   - gh-102027(7): Use ‘GetCurrentProcessId’ on Windows when ‘getpid’ is
     unavailable.  Patch by Max Bachmann.

   - gh-102056(8): Fix error handling bugs in interpreter’s exception
     printing code, which could cause a crash on infinite recursion.

   - gh-100982(9): Restrict the scope of the ‘FOR_ITER_RANGE’
     instruction to the scope of the original *note FOR_ITER: 1866.
     instruction, to allow instrumentation.

   - gh-101967(10): Fix possible segfault in
     ‘positional_only_passed_as_keyword’ function, when new list
     created.

   - gh-101952(11): Fix possible segfault in ‘BUILD_SET’ opcode, when
     new set created.

   - gh-74895(12): *note socket.getaddrinfo: 15ba. no longer raises
     *note OverflowError: 888. for *note int: 257. 'port' values outside
     of the C long range.  Out of range values are left up to the
     underlying string based C library API to report.  A *note
     socket.gaierror: 1867. ‘SAI_SERVICE’ may occur instead, or no error
     at all as not all platform C libraries generate an error.

   - gh-101799(13): Add *note CALL_INTRINSIC_2: 4e5. and use it instead
     of ‘PREP_RERAISE_STAR’.

   - gh-101857(14): Fix xattr support detection on Linux systems by
     widening the check to linux, not just glibc.  This fixes support
     for musl.

   - gh-84783(15): Make the slice object hashable.  Patch by Will
     Bradshaw and Furkan Onder.

   - gh-87849(16): Change the ‘SEND’ instruction to leave the receiver
     on the stack.  This allows the specialized form of ‘SEND’ to skip
     the chain of C calls and jump directly to the ‘RESUME’ in the
     generator or coroutine.

   - gh-101765(17): Fix SystemError / segmentation fault in iter
     ‘__reduce__’ when internal access of ‘builtins.__dict__’ keys
     mutates the iter object.

   - gh-101430(18): Update *note tracemalloc: ff. to handle presize of
     object properly.  Patch by Donghee Na.

   - gh-101696(19): Invalidate type version tag in
     ‘_PyStaticType_Dealloc’ for static types, avoiding bug where a
     false cache hit could crash the interpreter.  Patch by Kumar
     Aditya.

   - gh-101632(20): Adds a new *note RETURN_CONST: 4ec. instruction.

   - gh-100719(21): Remove gi_code field from generator (and coroutine
     and async generator) objects as it is redundant.  The frame already
     includes a reference to the code object.

   - gh-98627(22): When an interpreter is configured to check (and only
     then), importing an extension module will now fail when the
     extension does not support multiple interpreters (i.e.  doesn’t
     implement PEP 489 multi-phase init).  This does not apply to the
     main interpreter, nor to subinterpreters created with
     ‘Py_NewInterpreter()’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102493

   (2) https://github.com/python/cpython/issues/102416

   (3) https://github.com/python/cpython/issues/102356

   (4) https://github.com/python/cpython/issues/102336

   (5) https://github.com/python/cpython/issues/102250

   (6) https://github.com/python/cpython/issues/102126

   (7) https://github.com/python/cpython/issues/102027

   (8) https://github.com/python/cpython/issues/102056

   (9) https://github.com/python/cpython/issues/100982

   (10) https://github.com/python/cpython/issues/101967

   (11) https://github.com/python/cpython/issues/101952

   (12) https://github.com/python/cpython/issues/74895

   (13) https://github.com/python/cpython/issues/101799

   (14) https://github.com/python/cpython/issues/101857

   (15) https://github.com/python/cpython/issues/84783

   (16) https://github.com/python/cpython/issues/87849

   (17) https://github.com/python/cpython/issues/101765

   (18) https://github.com/python/cpython/issues/101430

   (19) https://github.com/python/cpython/issues/101696

   (20) https://github.com/python/cpython/issues/101632

   (21) https://github.com/python/cpython/issues/100719

   (22) https://github.com/python/cpython/issues/98627


File: python.info,  Node: Library<46>,  Next: Documentation<21>,  Prev: Core and Builtins<42>,  Up: Python 3 12 0 alpha 6

1.23.30.3 Library
.................

   - gh-102302(1): Micro-optimise hashing of *note inspect.Parameter:
     1d0, reducing the time it takes to hash an instance by around 40%.

   - gh-101979(2): Fix a bug where parentheses in the ‘metavar’ argument
     to *note argparse.ArgumentParser.add_argument(): 19e. were dropped.
     Patch by Yeojin Kim.

   - gh-91038(3): *note platform.platform(): 1869. now has boolean
     default arguments.

   - gh-81652(4): Add *note mmap.MAP_ALIGNED_SUPER: 186a. FreeBSD and
     *note mmap.MAP_CONCEAL: 186b. OpenBSD constants to *note mmap: 90.
     Patch by Yeojin Kim.

   - gh-102179(5): Fix *note os.dup2(): b7f. error message for negative
     fds.

   - gh-101961(6): For the binary mode, ‘fileinput.hookcompressed()’
     doesn’t set the ‘encoding’ value even if the value is ‘None’.
     Patch by Gihwan Kim.

   - gh-101936(7): The default value of ‘fp’ becomes *note io.BytesIO:
     ed8. if *note HTTPError: 1019. is initialized without a designated
     ‘fp’ parameter.  Patch by Long Vo.

   - gh-101566(8): In zipfile, sync Path with zipp 3.14(9), including
     fix for extractall on the underlying zipfile after being wrapped in
     ‘Path’.

   - gh-97930(10): Apply changes from importlib_resources 5.12(11),
     including fix for ‘MultiplexedPath’ to support directories in
     multiple namespaces (python/importlib_resources#265).

   - gh-101997(12): Upgrade pip wheel bundled with ensurepip (pip
     23.0.1)

   - gh-99108(13): The built-in extension modules for *note hashlib: 68.
     SHA2 algorithms, used when OpenSSL does not provide them, now live
     in a single internal ‘_sha2’ module instead of separate ‘_sha256’
     and ‘_sha512’ modules.

   - gh-101892(14): Callable iterators no longer raise *note
     SystemError: 578. when the callable object exhausts the iterator
     but forgets to either return a sentinel value or raise *note
     StopIteration: c1b.

   - gh-87634(15): Remove locking behavior from *note
     functools.cached_property(): 544.

   - gh-97786(16): Fix potential undefined behaviour in corner cases of
     floating-point-to-time conversions.

   - gh-101517(17): Fixed bug where *note bdb: f. looks up the source
     line with *note linecache: 85. with a ‘lineno=None’, which causes
     it to fail with an unhandled exception.

   - gh-101773(18): Optimize *note fractions.Fraction: 1e7. for small
     components.  The private argument ‘_normalize’ of the
     ‘fractions.Fraction’ constructor has been removed.

   - gh-101693(19): In *note sqlite3.Cursor.execute(): 2d1, *note
     DeprecationWarning: 1a5. is now emitted when *note named
     placeholders: 2d3. are used together with parameters supplied as a
     *note sequence: 4f4. instead of as a *note dict: 256.  Starting
     from Python 3.14, using named placeholders with parameters supplied
     as a sequence will raise a *note ProgrammingError: 4f5.  Patch by
     Erlend E. Aasland.

   - gh-101446(20): Change repr of *note collections.OrderedDict: 5de.
     to use regular dictionary formatting instead of pairs of keys and
     values.

   - gh-101362(21): Speed up *note pathlib.PurePath: 4a9. construction
     by handling arguments more uniformly.  When a *note pathlib.Path:
     229. argument is supplied, we use its string representation rather
     than joining its parts with *note os.path.join(): 173c.

   - gh-101362(22): Speed up *note pathlib.PurePath: 4a9. construction
     by calling *note os.path.join(): 173c. only when two or more
     arguments are given.

   - gh-101362(23): Speed up *note pathlib.Path: 229. construction by
     running the path flavour compatibility check only when pathlib is
     imported.

   - gh-85984(24): Refactored the implementation of *note pty.fork():
     186c. to use *note os.login_tty(): 186d.

     A *note DeprecationWarning: 1a5. is now raised by
     ‘pty.master_open()’ and ‘pty.slave_open()’.  They were undocumented
     and deprecated long long ago in the docstring in favor of *note
     pty.openpty(): 2ce.

   - gh-101561(25): Add a new decorator *note typing.override(): 44e.
     See PEP 698(26) for details.  Patch by Steven Troxler.

   - gh-63301(27): Set exit code when *note tabnanny: dd. CLI exits on
     error.

   - gh-101360(28): Fix anchor matching in
     ‘pathlib.PureWindowsPath.match()’.  Path and pattern anchors are
     now matched with *note fnmatch: 5c, just like other path parts.
     This allows patterns such as ‘"*:/Users/*"’ to be matched.

   - gh-101277(29): Remove global state from *note itertools: 81. module
     ( PEP 687(30)).  Patches by Erlend E. Aasland.

   - gh-100809(31): Fix handling of drive-relative paths (like ‘C:’ and
     ‘C:foo’) in *note pathlib.Path.absolute(): 17bf.  This method now
     uses the OS API to retrieve the correct current working directory
     for the drive.

   - gh-99138(32): Apply PEP 687(33) to *note zoneinfo: 134.  Patch by
     Erlend E. Aasland.

   - gh-96764(34): *note asyncio.wait_for(): 602. now uses *note
     asyncio.timeout(): 601. as its underlying implementation.  Patch by
     Kumar Aditya.

   - gh-88233(35): Correctly preserve “extra” fields in ‘zipfile’
     regardless of their ordering relative to a zip64 “extra.”

   - bpo-23224(36): Fix segfaults when creating *note
     lzma.LZMADecompressor: 186e. and *note bz2.BZ2Decompressor: 186f.
     objects without calling ‘__init__()’, and fix leakage of locks and
     internal buffers when calling the ‘__init__()’ methods of
     ‘lzma.LZMADecompressor’, *note lzma.LZMACompressor: 1870, *note
     bz2.BZ2Compressor: 1871, and ‘bz2.BZ2Decompressor’ objects multiple
     times.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102302

   (2) https://github.com/python/cpython/issues/101979

   (3) https://github.com/python/cpython/issues/91038

   (4) https://github.com/python/cpython/issues/81652

   (5) https://github.com/python/cpython/issues/102179

   (6) https://github.com/python/cpython/issues/101961

   (7) https://github.com/python/cpython/issues/101936

   (8) https://github.com/python/cpython/issues/101566

   (9) https://zipp.readthedocs.io/en/latest/history.html#v3-14-0

   (10) https://github.com/python/cpython/issues/97930

   (11) 
https://importlib-resources.readthedocs.io/en/latest/history.html#v5-12-0

   (12) https://github.com/python/cpython/issues/101997

   (13) https://github.com/python/cpython/issues/99108

   (14) https://github.com/python/cpython/issues/101892

   (15) https://github.com/python/cpython/issues/87634

   (16) https://github.com/python/cpython/issues/97786

   (17) https://github.com/python/cpython/issues/101517

   (18) https://github.com/python/cpython/issues/101773

   (19) https://github.com/python/cpython/issues/101693

   (20) https://github.com/python/cpython/issues/101446

   (21) https://github.com/python/cpython/issues/101362

   (22) https://github.com/python/cpython/issues/101362

   (23) https://github.com/python/cpython/issues/101362

   (24) https://github.com/python/cpython/issues/85984

   (25) https://github.com/python/cpython/issues/101561

   (26) https://peps.python.org/pep-0698/

   (27) https://github.com/python/cpython/issues/63301

   (28) https://github.com/python/cpython/issues/101360

   (29) https://github.com/python/cpython/issues/101277

   (30) https://peps.python.org/pep-0687/

   (31) https://github.com/python/cpython/issues/100809

   (32) https://github.com/python/cpython/issues/99138

   (33) https://peps.python.org/pep-0687/

   (34) https://github.com/python/cpython/issues/96764

   (35) https://github.com/python/cpython/issues/88233

   (36) https://bugs.python.org/issue?@action=redirect&bpo=23224


File: python.info,  Node: Documentation<21>,  Next: Tests<24>,  Prev: Library<46>,  Up: Python 3 12 0 alpha 6

1.23.30.4 Documentation
.......................

   - gh-85417(1): Update *note cmath: 18. documentation to clarify
     behaviour on branch cuts.

   - gh-97725(2): Fix *note asyncio.Task.print_stack(): 1873.
     description for ‘file=None’.  Patch by Oleg Iarygin.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/85417

   (2) https://github.com/python/cpython/issues/97725


File: python.info,  Node: Tests<24>,  Next: Build<25>,  Prev: Documentation<21>,  Up: Python 3 12 0 alpha 6

1.23.30.5 Tests
...............

   - gh-102019(1): Fix deadlock on shutdown if
     ‘test_current_{exception,frames}’ fails.  Patch by Jacob Bower.

   - gh-85984(2): Utilize new “winsize” functions from termios in pty
     tests.

   - gh-89792(3): ‘test_tools’ now copies up to 10x less source data to
     a temporary directory during the ‘freeze’ test by ignoring git
     metadata and other artifacts.  It also limits its python build
     parallelism based on os.cpu_count instead of hard coding it as 8
     cores.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102019

   (2) https://github.com/python/cpython/issues/85984

   (3) https://github.com/python/cpython/issues/89792


File: python.info,  Node: Build<25>,  Next: Windows<22>,  Prev: Tests<24>,  Up: Python 3 12 0 alpha 6

1.23.30.6 Build
...............

   - gh-99942(1): On Android, in a static build, python-config in embed
     mode no longer incorrectly reports a library to link to.

   - gh-99942(2): On Android, python.pc now correctly reports the
     library to link to, the same as python-config.sh.

   - gh-100221(3): Fix creating install directories in ‘make
     sharedinstall’ if they exist outside ‘DESTDIR’ already.

   - gh-96821(4): Explicitly mark C extension modules that need defined
     signed integer overflow, and add a configure option *note
     -with-strict-overflow: 1876.  Patch by Matthias Görgens and
     Shantanu Jain.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99942

   (2) https://github.com/python/cpython/issues/99942

   (3) https://github.com/python/cpython/issues/100221

   (4) https://github.com/python/cpython/issues/96821


File: python.info,  Node: Windows<22>,  Next: macOS<16>,  Prev: Build<25>,  Up: Python 3 12 0 alpha 6

1.23.30.7 Windows
.................

   - gh-102344(1): Implement ‘winreg.QueryValue’ using ‘QueryValueEx’
     and ‘winreg.SetValue’ using ‘SetValueEx’.  Patch by Max Bachmann.

   - gh-101881(2): Handle read and write operations on non-blocking
     pipes properly on Windows.

   - gh-101881(3): Add support for the os.get_blocking() and
     os.set_blocking() functions on Windows.

   - gh-101849(4): Ensures installer will correctly upgrade existing
     ‘py.exe’ launcher installs.

   - gh-101763(5): Updates copy of libffi bundled with Windows installs
     to 3.4.4.

   - gh-101759(6): Update Windows installer to SQLite 3.40.1.

   - gh-101614(7): Correctly handle extensions built against debug
     binaries that reference ‘python3_d.dll’.

   - gh-101196(8): The functions ‘os.path.isdir’, ‘os.path.isfile’,
     ‘os.path.islink’ and ‘os.path.exists’ are now 13% to 28% faster on
     Windows, by making fewer Win32 API calls.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/102344

   (2) https://github.com/python/cpython/issues/101881

   (3) https://github.com/python/cpython/issues/101881

   (4) https://github.com/python/cpython/issues/101849

   (5) https://github.com/python/cpython/issues/101763

   (6) https://github.com/python/cpython/issues/101759

   (7) https://github.com/python/cpython/issues/101614

   (8) https://github.com/python/cpython/issues/101196


File: python.info,  Node: macOS<16>,  Next: C API<24>,  Prev: Windows<22>,  Up: Python 3 12 0 alpha 6

1.23.30.8 macOS
...............

   - gh-101759(1): Update macOS installer to SQLite 3.40.1.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101759


File: python.info,  Node: C API<24>,  Prev: macOS<16>,  Up: Python 3 12 0 alpha 6

1.23.30.9 C API
...............

   - gh-101907(1): Removes use of non-standard C++ extension in public
     header files.

   - gh-99293(2): Document that the Py_TPFLAGS_VALID_VERSION_TAG is an
     internal feature, should not be used, and will be removed.

   - gh-101578(3): Add *note PyErr_GetRaisedException(): 3f7. and *note
     PyErr_SetRaisedException(): 3fa. for saving and restoring the
     current exception.  These functions return and accept a single
     exception object, rather than the triple arguments of the
     now-deprecated *note PyErr_Fetch(): 3f6. and *note PyErr_Restore():
     3f9.  This is less error prone and a bit more efficient.

     Add *note PyException_GetArgs(): 56d. and *note
     PyException_SetArgs(): 56e. as convenience functions for retrieving
     and modifying the *note args: 56f. passed to the exception’s
     constructor.

   - gh-91744(4): Introduced the 'Unstable C API tier', marking APi that
     is allowed to change in minor releases without a deprecation
     period.  See PEP 689(5) for details.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101907

   (2) https://github.com/python/cpython/issues/99293

   (3) https://github.com/python/cpython/issues/101578

   (4) https://github.com/python/cpython/issues/91744

   (5) https://peps.python.org/pep-0689/


File: python.info,  Node: Python 3 12 0 alpha 5,  Next: Python 3 12 0 alpha 4,  Prev: Python 3 12 0 alpha 6,  Up: Changelog

1.23.31 Python 3.12.0 alpha 5
-----------------------------

'Release date: 2023-02-07'

* Menu:

* Security: Security<21>.
* Core and Builtins: Core and Builtins<43>.
* Library: Library<47>.
* Documentation: Documentation<22>.
* Tests: Tests<25>.
* Build: Build<26>.
* Windows: Windows<23>.


File: python.info,  Node: Security<21>,  Next: Core and Builtins<43>,  Up: Python 3 12 0 alpha 5

1.23.31.1 Security
..................

   - gh-99108(1): Replace the builtin *note hashlib: 68. implementations
     of SHA2-224 and SHA2-256 originally from LibTomCrypt with formally
     verified, side-channel resistant code from the HACL*(2) project.
     The builtins remain a fallback only used when OpenSSL does not
     provide them.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99108

   (2) https://github.com/hacl-star/hacl-star/


File: python.info,  Node: Core and Builtins<43>,  Next: Library<47>,  Prev: Security<21>,  Up: Python 3 12 0 alpha 5

1.23.31.2 Core and Builtins
...........................

   - gh-92173(1): Fix the ‘defs’ and ‘kwdefs’ arguments to *note
     PyEval_EvalCodeEx(): 187d. and a reference leak in that function.

   - gh-59956(2): The GILState API is now partially compatible with
     subinterpreters.  Previously, ‘PyThreadState_GET()’ and
     ‘PyGILState_GetThisThreadState()’ would get out of sync, causing
     inconsistent behavior and crashes.

   - gh-101400(3): Fix wrong lineno in exception message on *note
     continue: 9d4. or *note break: abe. which are not in a loop.  Patch
     by Donghee Na.

   - gh-101372(4): Fix *note is_normalized(): a55. to properly handle
     the UCD 3.2.0 cases.  Patch by Donghee Na.

   - gh-101266(5): Fix *note sys.getsizeof(): 187e. reporting for *note
     int: 257. subclasses.

   - gh-101291(6): Refactor the ‘PyLongObject’ struct into a normal
     Python object header and a ‘PyLongValue’ struct.

   - gh-101046(7): Fix a possible memory leak in the parser when raising
     *note MemoryError: 15ab.  Patch by Pablo Galindo

   - gh-101037(8): Fix potential memory underallocation issue for
     instances of *note int: 257. subclasses with value zero.

   - gh-100762(9): Record the (virtual) exception block depth in the
     oparg of *note YIELD_VALUE: 314.  Use this to avoid the expensive
     ‘throw()’ when closing generators (and coroutines) that can be
     closed trivially.

   - gh-100982(10): Adds a new ‘COMPARE_AND_BRANCH’ instruction.  This
     is a bit more efficient when performing a comparison immediately
     followed by a branch, and restores the design intent of PEP 659
     that specializations are local to a single instruction.

   - gh-100942(11): Fixed segfault in property.getter/setter/deleter
     that occurred when a property subclass overrode the ‘__new__’
     method to return a non-property instance.

   - gh-100923(12): Remove the ‘mask’ cache entry for the *note
     COMPARE_OP: 973. instruction and embed the mask into the oparg.

   - gh-100892(13): Fix race while iterating over thread states in
     clearing *note threading.local: 1650.  Patch by Kumar Aditya.

   - gh-91351(14): Fix a case where re-entrant imports could corrupt the
     import deadlock detection code and cause a *note KeyError: 345. to
     be raised out of ‘importlib/_bootstrap’.  In addition to the
     straightforward cases, this could also happen when garbage
     collection leads to a warning being emitted – as happens when it
     collects an open socket or file)

   - gh-100726(15): Optimize construction of ‘range’ object for medium
     size integers.

   - gh-100712(16): Added option to build cpython with specialization
     disabled, by setting ‘ENABLE_SPECIALIZATION=False’ in ‘opcode’,
     followed by ‘make regen-all’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92173

   (2) https://github.com/python/cpython/issues/59956

   (3) https://github.com/python/cpython/issues/101400

   (4) https://github.com/python/cpython/issues/101372

   (5) https://github.com/python/cpython/issues/101266

   (6) https://github.com/python/cpython/issues/101291

   (7) https://github.com/python/cpython/issues/101046

   (8) https://github.com/python/cpython/issues/101037

   (9) https://github.com/python/cpython/issues/100762

   (10) https://github.com/python/cpython/issues/100982

   (11) https://github.com/python/cpython/issues/100942

   (12) https://github.com/python/cpython/issues/100923

   (13) https://github.com/python/cpython/issues/100892

   (14) https://github.com/python/cpython/issues/91351

   (15) https://github.com/python/cpython/issues/100726

   (16) https://github.com/python/cpython/issues/100712


File: python.info,  Node: Library<47>,  Next: Documentation<22>,  Prev: Core and Builtins<43>,  Up: Python 3 12 0 alpha 5

1.23.31.3 Library
.................

   - bpo-32780(1): Inter-field padding is now inserted into the PEP3118
     format strings obtained from *note ctypes.Structure: 1d4. objects,
     reflecting their true representation in memory.

   - gh-101541(2): [Enum] - fix psuedo-flag creation

   - gh-101570(3): Upgrade pip wheel bundled with ensurepip (pip 23.0)

   - gh-101323(4): Fix a bug where errors where not thrown by
     zlib._ZlibDecompressor if encountered during decompressing.

   - gh-101317(5): Add 'ssl_shutdown_timeout' parameter for *note
     asyncio.StreamWriter.start_tls(): 607.

   - gh-101326(6): Fix regression when passing ‘None’ as second or third
     argument to ‘FutureIter.throw’.

   - gh-92123(7): Adapt the ‘_elementtree’ extension module to
     multi-phase init ( PEP 489(8)).  Patches by Erlend E. Aasland.

   - gh-100795(9): Avoid potential unexpected ‘freeaddrinfo’ call
     (double free) in *note socket: cc. when when a libc ‘getaddrinfo()’
     implementation leaves garbage in an output pointer when returning
     an error.  Original patch by Sergey G. Brester.

   - gh-101143(10): Remove unused references to *note TimerHandle: 1880.
     in ‘asyncio.base_events.BaseEventLoop._add_callback’.

   - gh-101144(11): Make *note zipfile.Path.open(): 169f. and *note
     zipfile.Path.read_text(): 1881. also accept ‘encoding’ as a
     positional argument.  This was the behavior in Python 3.9 and
     earlier.  3.10 introduced a regression where supplying it as a
     positional argument would lead to a *note TypeError: 2c3.

   - gh-94518(12): Group-related variables of ‘_posixsubprocess’ module
     are renamed to stress that supplementary group affinity is added to
     a fork, not replace the inherited ones.  Patch by Oleg Iarygin.

   - gh-101015(13): Fix *note typing.get_type_hints(): 6b4. on
     ‘'*tuple[...]'’ and ‘*tuple[...]’.  It must not drop the ‘Unpack’
     part.

   - gh-101000(14): Add *note os.path.splitroot(): 4a7, which splits a
     path into a 3-item tuple ‘(drive, root, tail)’.  This new function
     is used by *note pathlib: a4. to improve the performance of path
     construction by up to a third.

   - gh-100573(15): Fix a Windows *note asyncio: a. bug with named pipes
     where a client doing ‘os.stat()’ on the pipe would cause an error
     in the server that disabled serving future requests.

   - gh-39615(16): *note warnings.warn(): 1569. now has the ability to
     skip stack frames based on code filename prefix rather than only a
     numeric ‘stacklevel’ via the new ‘skip_file_prefixes’ keyword
     argument.

   - gh-100750(17): pass encoding kwarg to subprocess in platform

   - gh-100160(18): Emit a deprecation warning in
     ‘asyncio.DefaultEventLoopPolicy.get_event_loop()’ if there is no
     current event loop set and it decides to create one.

   - gh-96290(19): Fix handling of partial and invalid UNC drives in
     ‘ntpath.splitdrive()’, and in ‘ntpath.normpath()’ on non-Windows
     systems.  Paths such as ‘\server’ and ‘\’ are now considered by
     ‘splitdrive()’ to contain only a drive, and consequently are not
     modified by ‘normpath()’ on non-Windows systems.  The behaviour of
     ‘normpath()’ on Windows systems is unaffected, as native OS APIs
     are used.  Patch by Eryk Sun, with contributions by Barney Gale.

   - gh-99952(20): Fix a reference undercounting issue in *note
     ctypes.Structure: 1d4. with ‘from_param()’ results larger than a C
     pointer.

   - gh-67790(21): Add float-style formatting support for *note
     fractions.Fraction: 1e7. instances.

   - gh-99266(22): Preserve more detailed error messages in *note
     ctypes: 2a.

   - gh-86682(23): Ensure runtime-created collections have the correct
     module name using the newly added (internal) *note
     sys._getframemodulename(): 1882.

   - gh-88597(24): *note uuid: 110. now has a command line interface.
     Try ‘python -m uuid -h’.

   - gh-60580(25): ‘ctypes.wintypes.BYTE’ definition changed from *note
     c_byte: 1883. to *note c_ubyte: 1884. to match Windows SDK. Patch
     by Anatoly Techtonik and Oleg Iarygin.

   - gh-94518(26): ‘_posixsubprocess’ now initializes all UID and GID
     variables using a reserved ‘-1’ value instead of a separate flag.
     Patch by Oleg Iarygin.

   - bpo-38941(27): The *note xml.etree.ElementTree: 125. module now
     emits *note DeprecationWarning: 1a5. when testing the truth value
     of an *note xml.etree.ElementTree.Element: 310.  Before, the Python
     implementation emitted *note FutureWarning: 418, and the C
     implementation emitted nothing.

   - bpo-40077(28): Convert ‘elementtree’ types to heap types.  Patch by
     Erlend E. Aasland.

   - bpo-29847(29): Fix a bug where *note pathlib.Path: 229. accepted
     and ignored keyword arguments.  Patch provided by Yurii Karabas.

   - gh-77772(30): *note ctypes.CDLL: 9f4, *note ctypes.OleDLL: 1885,
     *note ctypes.WinDLL: 1886, and *note ctypes.PyDLL: 1887. now accept
     *note path-like objects: 2a0. as their ‘name’ argument.  Patch by
     Robert Hoelzl.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32780

   (2) https://github.com/python/cpython/issues/101541

   (3) https://github.com/python/cpython/issues/101570

   (4) https://github.com/python/cpython/issues/101323

   (5) https://github.com/python/cpython/issues/101317

   (6) https://github.com/python/cpython/issues/101326

   (7) https://github.com/python/cpython/issues/92123

   (8) https://peps.python.org/pep-0489/

   (9) https://github.com/python/cpython/issues/100795

   (10) https://github.com/python/cpython/issues/101143

   (11) https://github.com/python/cpython/issues/101144

   (12) https://github.com/python/cpython/issues/94518

   (13) https://github.com/python/cpython/issues/101015

   (14) https://github.com/python/cpython/issues/101000

   (15) https://github.com/python/cpython/issues/100573

   (16) https://github.com/python/cpython/issues/39615

   (17) https://github.com/python/cpython/issues/100750

   (18) https://github.com/python/cpython/issues/100160

   (19) https://github.com/python/cpython/issues/96290

   (20) https://github.com/python/cpython/issues/99952

   (21) https://github.com/python/cpython/issues/67790

   (22) https://github.com/python/cpython/issues/99266

   (23) https://github.com/python/cpython/issues/86682

   (24) https://github.com/python/cpython/issues/88597

   (25) https://github.com/python/cpython/issues/60580

   (26) https://github.com/python/cpython/issues/94518

   (27) https://bugs.python.org/issue?@action=redirect&bpo=38941

   (28) https://bugs.python.org/issue?@action=redirect&bpo=40077

   (29) https://bugs.python.org/issue?@action=redirect&bpo=29847

   (30) https://github.com/python/cpython/issues/77772


File: python.info,  Node: Documentation<22>,  Next: Tests<25>,  Prev: Library<47>,  Up: Python 3 12 0 alpha 5

1.23.31.4 Documentation
.......................

   - gh-88324(1): Reword *note subprocess: d6. to emphasize default
     behavior of 'stdin', 'stdout', and 'stderr' arguments.  Remove
     inaccurate statement about child file handle inheritance.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88324


File: python.info,  Node: Tests<25>,  Next: Build<26>,  Prev: Documentation<22>,  Up: Python 3 12 0 alpha 5

1.23.31.5 Tests
...............

   - gh-101334(1): ‘test_tarfile’ has been updated to pass when run as a
     high UID.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101334


File: python.info,  Node: Build<26>,  Next: Windows<23>,  Prev: Tests<25>,  Up: Python 3 12 0 alpha 5

1.23.31.6 Build
...............

   - gh-101282(1): Update BOLT configuration not to use deprecated usage
     of ‘--split functions’.  Patch by Donghee Na.

   - gh-101522(2): Allow overriding Windows dependencies versions and
     paths using MSBuild properties.

   - gh-77532(3): Minor fixes to allow building with
     ‘PlatformToolset=ClangCL’ on Windows.

   - gh-101152(4): In accordance with PEP 699(5), the ‘ma_version_tag’
     field in *note PyDictObject: 3c4. is deprecated for extension
     modules.  Accessing this field will generate a compiler warning at
     compile time.  This field will be removed in Python 3.14.

   - gh-100340(6): Allows -Wno-int-conversion for wasm-sdk 17 and
     onwards, thus enables building WASI builds once against the latest
     sdk.

   - gh-101060(7): Conditionally add ‘-fno-reorder-blocks-and-partition’
     in configure.  Effectively fixes ‘--enable-bolt’ when using Clang,
     as this appears to be a GCC-only flag.

   - gh-98705(8): ‘__bool__’ is defined in AIX system header files which
     breaks the build in AIX, so undefine it.

   - gh-98636(9): Fix a regression in detecting ‘gdbm_compat’ library
     for the ‘_gdbm’ module build.

   - gh-96305(10): ‘_aix_support’ now uses a simple code to get platform
     details rather than the now non-existent ‘_bootsubprocess’ during
     bootstrap.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101282

   (2) https://github.com/python/cpython/issues/101522

   (3) https://github.com/python/cpython/issues/77532

   (4) https://github.com/python/cpython/issues/101152

   (5) https://peps.python.org/pep-0699/

   (6) https://github.com/python/cpython/issues/100340

   (7) https://github.com/python/cpython/issues/101060

   (8) https://github.com/python/cpython/issues/98705

   (9) https://github.com/python/cpython/issues/98636

   (10) https://github.com/python/cpython/issues/96305


File: python.info,  Node: Windows<23>,  Prev: Build<26>,  Up: Python 3 12 0 alpha 5

1.23.31.7 Windows
.................

   - gh-101543(1): Ensure the install path in the registry is only used
     when the standard library hasn’t been located in any other way.

   - gh-101467(2): The ‘py.exe’ launcher now correctly filters when only
     a single runtime is installed.  It also correctly handles prefix
     matches on tags so that ‘-3.1’ does not match ‘3.11’, but would
     still match ‘3.1-32’.

   - gh-99834(3): Updates bundled copy of Tcl/Tk to 8.6.13.0

   - gh-101135(4): Restore ability to launch older 32-bit versions from
     the ‘py.exe’ launcher when both 32-bit and 64-bit installs of the
     same version are available.

   - gh-82052(5): Fixed an issue where writing more than 32K of Unicode
     output to the console screen in one go can result in mojibake.

   - gh-100320(6): Ensures the ‘PythonPath’ registry key from an install
     is used when launching from a different copy of Python that relies
     on an existing install to provide a copy of its modules and
     standard library.

   - gh-100247(7): Restores support for the ‘py.exe’ launcher finding
     shebang commands in its configuration file using the full command
     name.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/101543

   (2) https://github.com/python/cpython/issues/101467

   (3) https://github.com/python/cpython/issues/99834

   (4) https://github.com/python/cpython/issues/101135

   (5) https://github.com/python/cpython/issues/82052

   (6) https://github.com/python/cpython/issues/100320

   (7) https://github.com/python/cpython/issues/100247


File: python.info,  Node: Python 3 12 0 alpha 4,  Next: Python 3 12 0 alpha 3,  Prev: Python 3 12 0 alpha 5,  Up: Changelog

1.23.32 Python 3.12.0 alpha 4
-----------------------------

'Release date: 2023-01-10'

* Menu:

* Core and Builtins: Core and Builtins<44>.
* Library: Library<48>.
* Core and Builtins: Core and Builtins<45>.
* Library: Library<49>.
* Core and Builtins: Core and Builtins<46>.
* Library: Library<50>.
* Documentation: Documentation<23>.
* Tests: Tests<26>.
* Build: Build<27>.
* Windows: Windows<24>.
* macOS: macOS<17>.
* Tools/Demos: Tools/Demos<15>.
* C API: C API<25>.


File: python.info,  Node: Core and Builtins<44>,  Next: Library<48>,  Up: Python 3 12 0 alpha 4

1.23.32.1 Core and Builtins
...........................

   - gh-100776(1): Fix misleading default value in *note input():
     1320.’s ‘__text_signature__’.

   - gh-99005(2): Remove ‘UNARY_POSITIVE’, ‘ASYNC_GEN_WRAP’ and
     ‘LIST_TO_TUPLE’, replacing them with intrinsics.

   - gh-99005(3): Add new *note CALL_INTRINSIC_1: 4e4. instruction.
     Remove ‘IMPORT_STAR’, ‘PRINT_EXPR’ and ‘STOPITERATION_ERROR’,
     replacing them with the ‘CALL_INTRINSIC_1’ instruction.

   - gh-100288(4): Remove the LOAD_ATTR_METHOD_WITH_DICT specialized
     instruction.  Stats show it is not useful.

   - gh-100720(5): Added ‘_PyFrame_NumSlotsForCodeObject’, which returns
     the number of slots needed in a frame for a given code object.

   - gh-100719(6): Removed the co_nplaincellvars field from the code
     object, as it is redundant.

   - gh-100637(7): Fix ‘int.__sizeof__()’ calculation to include the
     1-element ‘ob_digit’ array for ‘0’ and ‘False’.

   - gh-100649(8): Update the native_thread_id field of PyThreadState
     after fork.

   - gh-100126(9): Fix an issue where “incomplete” frames could be
     briefly visible to C code while other frames are being torn down,
     possibly resulting in corruption or hard crashes of the interpreter
     while running finalizers.

   - gh-87447(10): Fix *note SyntaxError: 18d. on comprehension rebind
     checking with names that are not actually redefined.

     Now reassigning ‘b’ in ‘[(b := 1) for a, b.prop in some_iter]’ is
     allowed.  Reassigning ‘a’ is still disallowed as per PEP 572(11).

   - gh-100268(12): Add *note int.is_integer(): 188e. to improve duck
     type compatibility between *note int: 257. and *note float: 2f7.

   - gh-100425(13): Improve the accuracy of ‘sum()’ with compensated
     summation.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100776

   (2) https://github.com/python/cpython/issues/99005

   (3) https://github.com/python/cpython/issues/99005

   (4) https://github.com/python/cpython/issues/100288

   (5) https://github.com/python/cpython/issues/100720

   (6) https://github.com/python/cpython/issues/100719

   (7) https://github.com/python/cpython/issues/100637

   (8) https://github.com/python/cpython/issues/100649

   (9) https://github.com/python/cpython/issues/100126

   (10) https://github.com/python/cpython/issues/87447

   (11) https://peps.python.org/pep-0572/

   (12) https://github.com/python/cpython/issues/100268

   (13) https://github.com/python/cpython/issues/100425


File: python.info,  Node: Library<48>,  Next: Core and Builtins<45>,  Prev: Core and Builtins<44>,  Up: Python 3 12 0 alpha 4

1.23.32.2 Library
.................

   - gh-100374(1): Fix incorrect result and delay in *note
     socket.getfqdn(): 1890.  Patch by Dominic Socular.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100374


File: python.info,  Node: Core and Builtins<45>,  Next: Library<49>,  Prev: Library<48>,  Up: Python 3 12 0 alpha 4

1.23.32.3 Core and Builtins
...........................

   - gh-100357(1): Convert ‘vars’, ‘dir’, ‘next’, ‘getattr’, and ‘iter’
     to argument clinic.

   - gh-100117(2): Improve the output of *note codeobject.co_lines():
     2fb. by emitting only one entry for each line range.

   - gh-90043(3): Handle NaNs when specializing *note COMPARE_OP: 973.
     for *note float: 2f7. values.

   - gh-100222(4): Redefine the ‘_Py_CODEUNIT’ typedef as a union to
     describe its layout to the C compiler, avoiding type punning and
     improving clarity.

   - gh-99955(5): Internal compiler functions (in compile.c) now
     consistently return -1 on error and 0 on success.

   - gh-100188(6): The ‘BINARY_SUBSCR_LIST_INT’ and
     ‘BINARY_SUBSCR_TUPLE_INT’ instructions are no longer used for
     negative integers because those instructions always miss when
     encountering negative integers.

   - gh-99110(7): Initialize frame->previous in frameobject.c to fix a
     segmentation fault when accessing frames created by *note
     PyFrame_New(): 1892.

   - gh-94155(8): Improved the hashing algorithm for code objects,
     mitigating some hash collisions.

   - gh-99540(9): ‘None’ now hashes to a constant value.  This is not a
     requirements change.

   - gh-100143(10): When built with ‘--enable-pystats’, stats collection
     is now off by default.  To enable it early at startup, pass the
     ‘-Xpystats’ flag.  Stats are now always dumped, even if switched
     off.

   - gh-100146(11): Improve ‘BUILD_LIST’ opcode so that it works
     similarly to the ‘BUILD_TUPLE’ opcode, by stealing references from
     the stack rather than repeatedly using stack operations to set list
     elements.  Implementation details are in a new private API
     ‘_PyList_FromArraySteal()’.

   - gh-100110(12): Specialize ‘FOR_ITER’ for tuples.

   - gh-100050(13): Honor existing errors obtained when searching for
     mismatching parentheses in the tokenizer.  Patch by Pablo Galindo

   - gh-92216(14): Improve the performance of *note hasattr(): 4d5. for
     type objects with a missing attribute.

   - gh-99582(15): Freeze *note zipimport: 132. module into
     ‘_bootstrap_python’.

   - gh-99554(16): Pack debugging location tables more efficiently
     during bytecode compilation.

   - gh-98522(17): Add an internal version number to code objects, to
     give better versioning of inner functions and comprehensions, and
     thus better specialization of those functions.  This change is
     invisible to both Python and C extensions.

   - gh-94603(18): Improve performance of ‘list.pop’ for small lists.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100357

   (2) https://github.com/python/cpython/issues/100117

   (3) https://github.com/python/cpython/issues/90043

   (4) https://github.com/python/cpython/issues/100222

   (5) https://github.com/python/cpython/issues/99955

   (6) https://github.com/python/cpython/issues/100188

   (7) https://github.com/python/cpython/issues/99110

   (8) https://github.com/python/cpython/issues/94155

   (9) https://github.com/python/cpython/issues/99540

   (10) https://github.com/python/cpython/issues/100143

   (11) https://github.com/python/cpython/issues/100146

   (12) https://github.com/python/cpython/issues/100110

   (13) https://github.com/python/cpython/issues/100050

   (14) https://github.com/python/cpython/issues/92216

   (15) https://github.com/python/cpython/issues/99582

   (16) https://github.com/python/cpython/issues/99554

   (17) https://github.com/python/cpython/issues/98522

   (18) https://github.com/python/cpython/issues/94603


File: python.info,  Node: Library<49>,  Next: Core and Builtins<46>,  Prev: Core and Builtins<45>,  Up: Python 3 12 0 alpha 4

1.23.32.4 Library
.................

   - gh-89051(1): Add *note ssl.OP_LEGACY_SERVER_CONNECT: 1894.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89051


File: python.info,  Node: Core and Builtins<46>,  Next: Library<50>,  Prev: Library<49>,  Up: Python 3 12 0 alpha 4

1.23.32.5 Core and Builtins
...........................

   - bpo-32782(1): ‘ctypes’ arrays of length 0 now report a correct
     itemsize when a ‘memoryview’ is constructed from them, rather than
     always giving a value of 0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32782


File: python.info,  Node: Library<50>,  Next: Documentation<23>,  Prev: Core and Builtins<46>,  Up: Python 3 12 0 alpha 4

1.23.32.6 Library
.................

   - gh-100833(1): Speed up *note math.fsum(): 1422. by removing
     defensive ‘volatile’ qualifiers.

   - gh-100805(2): Modify *note random.choice(): 1276. implementation to
     once again work with NumPy arrays.

   - gh-100813(3): Add ‘socket.IP_PKTINFO’ constant.

   - gh-100792(4): Make *note email.message.Message.__contains__():
     1897. twice as fast.

   - gh-91851(5): Microoptimizations for *note
     fractions.Fraction.__round__(): 1898, *note
     fractions.Fraction.__ceil__(): 1899. and *note
     fractions.Fraction.__floor__(): 189a.

   - gh-90104(6): Avoid RecursionError on ‘repr’ if a dataclass field
     definition has a cyclic reference.

   - gh-100689(7): Fix crash in ‘pyexpat’ by statically allocating
     ‘PyExpat_CAPI’ capsule.

   - gh-100740(8): Fix ‘unittest.mock.Mock’ not respecting the spec for
     attribute names prefixed with ‘assert’.

   - gh-91219(9): Change ‘SimpleHTTPRequestHandler’ to support
     subclassing to provide a different set of index file names instead
     of using ‘__init__’ parameters.

   - gh-100690(10): ‘Mock’ objects which are not unsafe will now raise
     an ‘AttributeError’ when accessing an attribute that matches the
     name of an assertion but without the prefix ‘assert_’, e.g.
     accessing ‘called_once’ instead of ‘assert_called_once’.  This is
     in addition to this already happening for accessing attributes with
     prefixes ‘assert’, ‘assret’, ‘asert’, ‘aseert’, and ‘assrt’.

   - gh-89727(11): Simplify and optimize *note os.walk(): 4ac. by using
     *note isinstance(): 445. checks to check the top of the stack.

   - gh-100485(12): Add math.sumprod() to compute the sum of products.

   - gh-86508(13): Fix *note asyncio.open_connection(): b31. to skip
     binding to local addresses of different family.  Patch by Kumar
     Aditya.

   - gh-97930(14): ‘importlib.resources.files’ now accepts a module as
     an anchor instead of only accepting packages.  If a module is
     passed, resources are resolved adjacent to that module (in the same
     package or at the package root).  The parameter was renamed from
     ‘package’ to ‘anchor’ with a compatibility shim for those passing
     by keyword.  Additionally, the new ‘anchor’ parameter is now
     optional and will default to the caller’s module.

   - gh-100585(15): Fixed a bug where importlib.resources.as_file was
     leaving file pointers open

   - gh-100562(16): Improve performance of *note
     pathlib.Path.absolute(): 17bf. by nearly 2x.  This comes at the
     cost of a performance regression in *note pathlib.Path.cwd(): 183b,
     which is generally used less frequently in user code.

   - gh-100519(17): Small simplification of
     ‘http.cookiejar.eff_request_host()’ that improves readability and
     better matches the RFC wording.

   - gh-100287(18): Fix the interaction of *note unittest.mock.seal():
     bbf. with *note unittest.mock.AsyncMock: a57.

   - gh-100488(19): Add ‘Fraction.is_integer()’ to check whether a *note
     fractions.Fraction: 1e7. is an integer.  This improves duck type
     compatibility with *note float: 2f7. and *note int: 257.

   - gh-100474(20): *note http.server: 72. now checks that an index page
     is actually a regular file before trying to serve it.  This avoids
     issues with directories named ‘index.html’.

   - gh-100363(21): Speed up *note asyncio.get_running_loop(): b24. by
     removing redundant ‘getpid’ checks.  Patch by Kumar Aditya.

   - gh-78878(22): Fix crash when creating an instance of
     ‘_ctypes.CField’.

   - gh-100348(23): Fix ref cycle in ‘asyncio._SelectorSocketTransport’
     by removing ‘_read_ready_cb’ in ‘close’.

   - gh-100344(24): Provide C implementation for *note
     asyncio.current_task(): 480. for a 4x-6x speedup.

   - gh-100272(25): Fix JSON serialization of OrderedDict.  It now
     preserves the order of keys.

   - gh-83076(26): Instantiation of ‘Mock()’ and ‘AsyncMock()’ is now
     3.8x faster.

   - gh-100234(27): Set a default value of 1.0 for the ‘lambd’ parameter
     in random.expovariate().

   - gh-100228(28): A *note DeprecationWarning: 1a5. may be raised when
     *note os.fork(): 197. or *note os.forkpty(): 198. is called from
     multi-threaded processes.  Forking with threads is unsafe and can
     cause deadlocks, crashes and subtle problems.  Lack of a warning
     does not indicate that the fork call was actually safe, as Python
     may not be aware of all threads.

   - gh-100039(29): Improve signatures for enums and flags.

   - gh-100133(30): Fix regression in *note asyncio: a. where a
     subprocess would sometimes lose data received from pipe.

   - bpo-44592(31): Fixes inconsistent handling of case sensitivity of
     'extrasaction' arg in *note csv.DictWriter: 1243.

   - gh-100098(32): Fix ‘tuple’ subclasses being cast to ‘tuple’ when
     used as enum values.

   - gh-85432(33): Rename the 'fmt' parameter of the pure-Python
     implementation of *note datetime.time.strftime(): 189b. to
     'format'.  Rename the 't' parameter of *note
     datetime.datetime.fromtimestamp(): 4f0. to 'timestamp'.  These
     changes mean the parameter names in the pure-Python implementation
     now match the parameter names in the C implementation.  Patch by
     Alex Waygood.

   - gh-98778(34): Update *note HTTPError: 1019. to be initialized
     properly, even if the ‘fp’ is ‘None’.  Patch by Donghee Na.

   - gh-99925(35): Unify error messages in JSON serialization between
     ‘json.dumps(float('nan'), allow_nan=False)’ and
     ‘json.dumps(float('nan'), allow_nan=False, indent=<SOMETHING>)’.
     Now both include the representation of the value that could not be
     serialized.

   - gh-89727(36): Fix issue with *note os.walk(): 4ac. where a *note
     RecursionError: d96. would occur on deep directory structures by
     adjusting the implementation of ‘os.walk()’ to be iterative instead
     of recursive.

   - gh-94943(37): Add *note Dataclass support: 189c. to the *note Enum:
     633. *note __repr__(): 189d.  When inheriting from a *note
     dataclass: 1cb, only show the field names in the value section of
     the member *note repr(): 803, and not the dataclass’ class name.

   - gh-83035(38): Fix *note inspect.getsource(): 1619. handling of
     decorator calls with nested parentheses.

   - gh-99576(39): Fix ‘.save()’ method for ‘LWPCookieJar’ and
     ‘MozillaCookieJar’: saved file was not truncated on repeated save.

   - gh-94912(40): Add *note inspect.markcoroutinefunction(): 493.
     decorator which manually marks a function as a coroutine for the
     benefit of ‘iscoroutinefunction()’.

   - gh-99509(41): Add PEP 585(42) support for
     ‘multiprocessing.queues.Queue’.

   - gh-99482(43): Remove ‘Jython’ partial compatibility code from
     several stdlib modules.

   - gh-99433(44): Fix *note doctest: 3a. failure on *note
     types.MethodWrapperType: 64e. in modules.

   - gh-85267(45): Several improvements to *note inspect.signature():
     73b.’s handling of ‘__text_signature’.  - Fixes a case where
     ‘inspect.signature()’ dropped parameters - Fixes a case where
     ‘inspect.signature()’ raised *note tokenize.TokenError: 545. -
     Allows ‘inspect.signature()’ to understand defaults involving
     binary operations of constants - ‘inspect.signature()’ is
     documented as only raising *note TypeError: 2c3. or *note
     ValueError: 202, but sometimes raised *note RuntimeError: 195.
     These cases now raise ‘ValueError’ - Removed a dead code path

   - gh-91166(46): *note asyncio: a. is optimized to avoid excessive
     copying when writing to socket and use *note sendmsg(): 479. if the
     platform supports it.  Patch by Kumar Aditya.

   - gh-98030(47): Add missing TCP socket options from Linux:
     ‘TCP_MD5SIG’, ‘TCP_THIN_LINEAR_TIMEOUTS’, ‘TCP_THIN_DUPACK’,
     ‘TCP_REPAIR’, ‘TCP_REPAIR_QUEUE’, ‘TCP_QUEUE_SEQ’,
     ‘TCP_REPAIR_OPTIONS’, ‘TCP_TIMESTAMP’, ‘TCP_CC_INFO’,
     ‘TCP_SAVE_SYN’, ‘TCP_SAVED_SYN’, ‘TCP_REPAIR_WINDOW’,
     ‘TCP_FASTOPEN_CONNECT’, ‘TCP_ULP’, ‘TCP_MD5SIG_EXT’,
     ‘TCP_FASTOPEN_KEY’, ‘TCP_FASTOPEN_NO_COOKIE’,
     ‘TCP_ZEROCOPY_RECEIVE’, ‘TCP_INQ’, ‘TCP_TX_DELAY’.

   - gh-88500(48): Reduced the memory usage of *note
     urllib.parse.unquote(): 189e. and *note
     urllib.parse.unquote_to_bytes(): 189f. on large values.

   - gh-96127(49): ‘inspect.signature’ was raising ‘TypeError’ on call
     with mock objects.  Now it correctly returns ‘(*args, **kwargs)’ as
     inferred signature.

   - gh-95882(50): Fix a 3.11 regression in *note asynccontextmanager():
     b42, which caused it to propagate exceptions with incorrect
     tracebacks and fix a 3.11 regression in *note contextmanager():
     1247, which caused it to propagate exceptions with incorrect
     tracebacks for *note StopIteration: c1b.

   - gh-78707(51): Deprecate passing more than one positional argument
     to *note pathlib.PurePath.relative_to(): 2ca. and *note
     is_relative_to(): 2c9.

   - gh-92122(52): Fix reStructuredText syntax errors in docstrings in
     the *note enum: 56. module.

   - gh-91851(53): Optimize the *note Fraction: 1e7. arithmetics for
     small components.

   - bpo-24132(54): Make *note pathlib.PurePath: 4a9. and *note Path:
     229. subclassable (private to start).  Previously, attempting to
     instantiate a subclass resulted in an *note AttributeError: 34e.
     being raised.  Patch by Barney Gale.

   - bpo-40447(55): Accept *note os.PathLike: c72. (such as *note
     pathlib.Path: 229.) in the ‘stripdir’ arguments of *note
     compileall.compile_file(): e11. and *note compileall.compile_dir():
     b3e.

   - bpo-36880(56): Fix a reference counting issue when a *note ctypes:
     2a. callback with return type *note py_object: 1486. returns
     ‘None’, which could cause crashes.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100833

   (2) https://github.com/python/cpython/issues/100805

   (3) https://github.com/python/cpython/issues/100813

   (4) https://github.com/python/cpython/issues/100792

   (5) https://github.com/python/cpython/issues/91851

   (6) https://github.com/python/cpython/issues/90104

   (7) https://github.com/python/cpython/issues/100689

   (8) https://github.com/python/cpython/issues/100740

   (9) https://github.com/python/cpython/issues/91219

   (10) https://github.com/python/cpython/issues/100690

   (11) https://github.com/python/cpython/issues/89727

   (12) https://github.com/python/cpython/issues/100485

   (13) https://github.com/python/cpython/issues/86508

   (14) https://github.com/python/cpython/issues/97930

   (15) https://github.com/python/cpython/issues/100585

   (16) https://github.com/python/cpython/issues/100562

   (17) https://github.com/python/cpython/issues/100519

   (18) https://github.com/python/cpython/issues/100287

   (19) https://github.com/python/cpython/issues/100488

   (20) https://github.com/python/cpython/issues/100474

   (21) https://github.com/python/cpython/issues/100363

   (22) https://github.com/python/cpython/issues/78878

   (23) https://github.com/python/cpython/issues/100348

   (24) https://github.com/python/cpython/issues/100344

   (25) https://github.com/python/cpython/issues/100272

   (26) https://github.com/python/cpython/issues/83076

   (27) https://github.com/python/cpython/issues/100234

   (28) https://github.com/python/cpython/issues/100228

   (29) https://github.com/python/cpython/issues/100039

   (30) https://github.com/python/cpython/issues/100133

   (31) https://bugs.python.org/issue?@action=redirect&bpo=44592

   (32) https://github.com/python/cpython/issues/100098

   (33) https://github.com/python/cpython/issues/85432

   (34) https://github.com/python/cpython/issues/98778

   (35) https://github.com/python/cpython/issues/99925

   (36) https://github.com/python/cpython/issues/89727

   (37) https://github.com/python/cpython/issues/94943

   (38) https://github.com/python/cpython/issues/83035

   (39) https://github.com/python/cpython/issues/99576

   (40) https://github.com/python/cpython/issues/94912

   (41) https://github.com/python/cpython/issues/99509

   (42) https://peps.python.org/pep-0585/

   (43) https://github.com/python/cpython/issues/99482

   (44) https://github.com/python/cpython/issues/99433

   (45) https://github.com/python/cpython/issues/85267

   (46) https://github.com/python/cpython/issues/91166

   (47) https://github.com/python/cpython/issues/98030

   (48) https://github.com/python/cpython/issues/88500

   (49) https://github.com/python/cpython/issues/96127

   (50) https://github.com/python/cpython/issues/95882

   (51) https://github.com/python/cpython/issues/78707

   (52) https://github.com/python/cpython/issues/92122

   (53) https://github.com/python/cpython/issues/91851

   (54) https://bugs.python.org/issue?@action=redirect&bpo=24132

   (55) https://bugs.python.org/issue?@action=redirect&bpo=40447

   (56) https://bugs.python.org/issue?@action=redirect&bpo=36880


File: python.info,  Node: Documentation<23>,  Next: Tests<26>,  Prev: Library<50>,  Up: Python 3 12 0 alpha 4

1.23.32.7 Documentation
.......................

   - gh-100616(1): Document existing ‘attr’ parameter to *note
     curses.window.vline(): 18a1. function in *note curses: 2b.

   - gh-100472(2): Remove claim in documentation that the ‘stripdir’,
     ‘prependdir’ and ‘limit_sl_dest’ parameters of *note
     compileall.compile_dir(): b3e. and *note compileall.compile_file():
     e11. could be *note bytes: 1c2.

   - bpo-25377(3): Clarify use of octal format of mode argument in
     help(os.chmod) as well as help(os.fchmod)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100616

   (2) https://github.com/python/cpython/issues/100472

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25377


File: python.info,  Node: Tests<26>,  Next: Build<27>,  Prev: Documentation<23>,  Up: Python 3 12 0 alpha 4

1.23.32.8 Tests
...............

   - gh-100454(1): Start running SSL tests with OpenSSL 3.1.0-beta1.

   - gh-100086(2): The Python test runner (libregrtest) now logs Python
     build information like “debug” vs “release” build, or LTO and PGO
     optimizations.  Patch by Victor Stinner.

   - gh-93018(3): Make two tests forgiving towards host system libexpat
     with backported security fixes applied.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100454

   (2) https://github.com/python/cpython/issues/100086

   (3) https://github.com/python/cpython/issues/93018


File: python.info,  Node: Build<27>,  Next: Windows<24>,  Prev: Tests<26>,  Up: Python 3 12 0 alpha 4

1.23.32.9 Build
...............

   - gh-100540(1): Removed the ‘--with-system-ffi’ ‘configure’ option;
     ‘libffi’ must now always be supplied by the system on all
     non-Windows platforms.  The option has had no effect on non-Darwin
     platforms for several releases, and in 3.11 only had the
     non-obvious effect of invoking ‘pkg-config’ to find ‘libffi’ and
     never setting ‘-DUSING_APPLE_OS_LIBFFI’.  Now on Darwin platforms
     ‘configure’ will first check for the OS ‘libffi’ and then fall back
     to the same processing as other platforms if it is not found.

   - gh-88267(2): Avoid exporting Python symbols in linked Windows
     applications when the core is built as static.

   - bpo-41916(3): Allow override of ac_cv_cxx_thread so that cross
     compiled python can set -pthread for CXX.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100540

   (2) https://github.com/python/cpython/issues/88267

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41916


File: python.info,  Node: Windows<24>,  Next: macOS<17>,  Prev: Build<27>,  Up: Python 3 12 0 alpha 4

1.23.32.10 Windows
..................

   - gh-100180(1): Update Windows installer to OpenSSL 1.1.1s

   - gh-99191(2): Use ‘_MSVC_LANG >= 202002L’ instead of less-precise
     ‘_MSC_VER >=1929’ to more accurately test for C++20 support in
     ‘PC/_wmimodule.cpp’.

   - gh-79218(3): Define ‘MS_WIN64’ for Mingw-w64 64bit, fix cython
     compilation failure.

   - gh-99941(4): Ensure that *note asyncio.Protocol.data_received():
     18a5. receives an immutable *note bytes: 1c2. object (as
     documented), instead of *note bytearray: 2ea.

   - bpo-43984(5): *note winreg.SetValueEx(): 18a6. now leaves the
     target value untouched in the case of conversion errors.
     Previously, ‘-1’ would be written in case of such errors.

   - bpo-34816(6): ‘hasattr(ctypes.windll, 'nonexistant')’ now returns
     ‘False’ instead of raising *note OSError: 41a.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100180

   (2) https://github.com/python/cpython/issues/99191

   (3) https://github.com/python/cpython/issues/79218

   (4) https://github.com/python/cpython/issues/99941

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43984

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34816


File: python.info,  Node: macOS<17>,  Next: Tools/Demos<15>,  Prev: Windows<24>,  Up: Python 3 12 0 alpha 4

1.23.32.11 macOS
................

   - gh-100180(1): Update macOS installer to OpenSSL 1.1.1s

   - gh-100540(2): Removed obsolete ‘dlfcn.h’ shim from the ‘_ctypes’
     extension module, which has not been necessary since Mac OS X 10.2.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100180

   (2) https://github.com/python/cpython/issues/100540


File: python.info,  Node: Tools/Demos<15>,  Next: C API<25>,  Prev: macOS<17>,  Up: Python 3 12 0 alpha 4

1.23.32.12 Tools/Demos
......................

   - bpo-45256(1): Fix a bug that caused an *note AttributeError: 34e.
     to be raised in ‘python-gdb.py’ when ‘py-locals’ is used without a
     frame.

   - gh-100342(2): Add missing ‘NULL’ check for possible allocation
     failure in ‘*args’ parsing in Argument Clinic.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45256

   (2) https://github.com/python/cpython/issues/100342


File: python.info,  Node: C API<25>,  Prev: Tools/Demos<15>,  Up: Python 3 12 0 alpha 4

1.23.32.13 C API
................

   - gh-99947(1): Raising SystemError on import will now have its cause
     be set to the original unexpected exception.

   - gh-99240(2): In argument parsing, after deallocating newly
     allocated memory, reset its pointer to NULL.

   - gh-98724(3): The *note Py_CLEAR: 57b, *note Py_SETREF: 57c. and
     *note Py_XSETREF: 57d. macros now only evaluate their arguments
     once.  If an argument has side effects, these side effects are no
     longer duplicated.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99947

   (2) https://github.com/python/cpython/issues/99240

   (3) https://github.com/python/cpython/issues/98724


File: python.info,  Node: Python 3 12 0 alpha 3,  Next: Python 3 12 0 alpha 2,  Prev: Python 3 12 0 alpha 4,  Up: Changelog

1.23.33 Python 3.12.0 alpha 3
-----------------------------

'Release date: 2022-12-06'

* Menu:

* Security: Security<22>.
* Core and Builtins: Core and Builtins<47>.
* Library: Library<51>.
* Core and Builtins: Core and Builtins<48>.
* Library: Library<52>.
* Documentation: Documentation<24>.
* Tests: Tests<27>.
* Build: Build<28>.
* Windows: Windows<25>.
* macOS: macOS<18>.
* Tools/Demos: Tools/Demos<16>.
* C API: C API<26>.


File: python.info,  Node: Security<22>,  Next: Core and Builtins<47>,  Up: Python 3 12 0 alpha 3

1.23.33.1 Security
..................

   - gh-100001(1): ‘python -m http.server’ no longer allows terminal
     control characters sent within a garbage request to be printed to
     the stderr server log.

     This is done by changing the *note http.server: 72.
     ‘BaseHTTPRequestHandler’ ‘.log_message’ method to replace control
     characters with a ‘\xHH’ hex escape before printing.

   - gh-87604(2): Avoid publishing list of active per-interpreter audit
     hooks via the *note gc: 60. module

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100001

   (2) https://github.com/python/cpython/issues/87604


File: python.info,  Node: Core and Builtins<47>,  Next: Library<51>,  Prev: Security<22>,  Up: Python 3 12 0 alpha 3

1.23.33.2 Core and Builtins
...........................

   - gh-99891(1): Fix a bug in the tokenizer that could cause infinite
     recursion when showing syntax warnings that happen in the first
     line of the source.  Patch by Pablo Galindo

   - gh-91054(2): Add *note PyCode_AddWatcher(): 569. and *note
     PyCode_ClearWatcher(): 56a. APIs to register callbacks to receive
     notification on creation and destruction of code objects.

   - gh-99729(3): Fix an issue that could cause frames to be visible to
     Python code as they are being torn down, possibly leading to memory
     corruption or hard crashes of the interpreter.

   - gh-99708(4): Fix bug where compiler crashes on an if expression
     with an empty body block.

   - gh-99578(5): Fix a reference bug in ‘_imp.create_builtin()’ after
     the creation of the first sub-interpreter for modules ‘builtins’
     and ‘sys’.  Patch by Victor Stinner.

   - gh-99581(6): Fixed a bug that was causing a buffer overflow if the
     tokenizer copies a line missing the newline character from a file
     that is as long as the available tokenizer buffer.  Patch by Pablo
     galindo

   - gh-99553(7): Fix bug where an *note ExceptionGroup: 1b6. subclass
     can wrap a *note BaseException: 5be.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99891

   (2) https://github.com/python/cpython/issues/91054

   (3) https://github.com/python/cpython/issues/99729

   (4) https://github.com/python/cpython/issues/99708

   (5) https://github.com/python/cpython/issues/99578

   (6) https://github.com/python/cpython/issues/99581

   (7) https://github.com/python/cpython/issues/99553


File: python.info,  Node: Library<51>,  Next: Core and Builtins<48>,  Prev: Core and Builtins<47>,  Up: Python 3 12 0 alpha 3

1.23.33.3 Library
.................

   - gh-99547(1): Add a function to os.path to check if a path is a
     junction: isjunction.  Add similar functionality to pathlib.Path as
     is_junction.

   - gh-99370(2): Fix zip path for venv created from a non-installed
     python on POSIX platforms.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99547

   (2) https://github.com/python/cpython/issues/99370


File: python.info,  Node: Core and Builtins<48>,  Next: Library<52>,  Prev: Library<51>,  Up: Python 3 12 0 alpha 3

1.23.33.4 Core and Builtins
...........................

   - gh-99377(1): Add audit events for thread creation and clear
     operations.

   - gh-98686(2): Remove the ‘BINARY_OP_GENERIC’ and
     ‘COMPARE_OP_GENERIC’ “specializations”.

   - gh-99298(3): Remove the remaining error paths for attribute
     specializations, and refuse to specialize attribute accesses on
     types that haven’t had *note PyType_Ready(): 77f. called on them
     yet.

   - gh-99127(4): Allow some features of *note syslog: dc. to the main
     interpreter only.  Patch by Donghee Na.

   - gh-91053(5): Optimizing interpreters and JIT compilers may need to
     invalidate internal metadata when functions are modified.  This
     change adds the ability to provide a callback that will be invoked
     each time a function is created, modified, or destroyed.

   - gh-90994(6): Improve error messages when there’s a syntax error
     with call arguments.  The following three cases are covered: - No
     value is assigned to a named argument, eg ‘foo(a=)’.  - A value is
     assigned to a star argument, eg ‘foo(*args=[0])’.  - A value is
     assigned to a double-star keyword argument, eg ‘foo(**kwarg={'a':
     0})’.

   - bpo-45026(7): Optimize the *note range: 94d. object iterator.  It
     is now smaller, faster iteration of ranges containing large
     numbers.  Smaller pickles, faster unpickling.

   - bpo-31718(8): Raise *note ValueError: 202. instead of *note
     SystemError: 578. when methods of uninitialized *note
     io.IncrementalNewlineDecoder: 17d8. objects are called.  Patch by
     Oren Milman.

   - bpo-38031(9): Fix a possible assertion failure in *note io.FileIO:
     1359. when the opener returns an invalid file descriptor.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99377

   (2) https://github.com/python/cpython/issues/98686

   (3) https://github.com/python/cpython/issues/99298

   (4) https://github.com/python/cpython/issues/99127

   (5) https://github.com/python/cpython/issues/91053

   (6) https://github.com/python/cpython/issues/90994

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45026

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31718

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38031


File: python.info,  Node: Library<52>,  Next: Documentation<24>,  Prev: Core and Builtins<48>,  Up: Python 3 12 0 alpha 3

1.23.33.5 Library
.................

   - gh-100001(1): Also escape s in the http.server
     BaseHTTPRequestHandler.log_message so that it is technically
     possible to parse the line and reconstruct what the original data
     was.  Without this a xHH is ambiguous as to if it is a hex
     replacement we put in or the characters r”x” came through in the
     original request line.

   - gh-99957(2): Add ‘frozen_default’ parameter to *note
     typing.dataclass_transform(): 4d7.

   - gh-79033(3): Fix *note asyncio.Server.wait_closed(): 17d9. to
     actually do what the docs promise – wait for all existing
     connections to complete, after closing the server.

   - gh-51524(4): Fix bug when calling trace.CoverageResults with valid
     infile.

   - gh-99645(5): Fix a bug in handling class cleanups in *note
     unittest.TestCase: 451.  Now ‘addClassCleanup()’ uses separate
     lists for different ‘TestCase’ subclasses, and ‘doClassCleanups()’
     only cleans up the particular class.

   - gh-99508(6): Fix ‘TypeError’ in
     ‘Lib/importlib/_bootstrap_external.py’ while calling
     ‘_imp.source_hash()’.

   - gh-66285(7): Fix *note asyncio: a. to not share event loop and
     signal wakeupfd in forked processes.  Patch by Kumar Aditya.

   - gh-97001(8): Release the GIL when calling termios APIs to avoid
     blocking threads.

   - gh-92647(9): Use final status of an enum to determine lookup or
     creation branch of functional API.

   - gh-99388(10): Add 'loop_factory' parameter to *note asyncio.run():
     47f. to allow specifying a custom event loop factory.  Patch by
     Kumar Aditya.

   - gh-99341(11): Fix *note ast.increment_lineno(): 18b0. to also cover
     *note ast.TypeIgnore: 18b1. when changing line numbers.

   - gh-99382(12): Check the number of arguments in substitution in user
     generics containing a *note TypeVarTuple: 15f. and one or more
     *note TypeVar: 15d.

   - gh-99379(13): Fix substitution of *note ParamSpec: 15e. followed by
     *note TypeVarTuple: 15f. in generic aliases.

   - gh-99344(14): Fix substitution of *note TypeVarTuple: 15f. and
     *note ParamSpec: 15e. together in user generics.

   - gh-99284(15): Remove ‘_use_broken_old_ctypes_structure_semantics_’
     old untested and undocumented hack from *note ctypes: 2a.

   - gh-99201(16): Fix *note IndexError: 1585. when initializing the
     config variables on Windows if ‘HAVE_DYNAMIC_LOADING’ is not set.

   - gh-99240(17): Fix double-free bug in Argument Clinic
     ‘str_converter’ by extracting memory clean up to a new
     ‘post_parsing’ section.

   - gh-64490(18): Fix refcount error when arguments are packed to tuple
     in Argument Clinic.

   - gh-99029(19): *note pathlib.PurePath.relative_to(): 2ca. now treats
     naked Windows drive paths as relative.  This brings its behaviour
     in line with other parts of pathlib.

   - gh-98253(20): The implementation of the typing module is now more
     resilient to reference leaks in binary extension modules.

     Previously, a reference leak in a typed C API-based extension
     module could leak internals of the typing module, which could in
     turn introduce leaks in essentially any other package with typed
     function signatures.  Although the typing package is not the
     original source of the problem, such non-local dependences
     exacerbate debugging of large-scale projects, and the
     implementation was therefore changed to reduce harm by providing
     better isolation.

   - gh-98458(21): Fix infinite loop in unittest when a self-referencing
     chained exception is raised

   - gh-93453(22): *note asyncio.get_event_loop(): 2c2. and many other
     *note asyncio: a. functions like *note asyncio.ensure_future():
     c98, *note asyncio.shield(): a7f. or *note asyncio.gather(): 600,
     and also the ‘get_event_loop()’ method of
     ‘asyncio.BaseDefaultEventLoopPolicy’ now raise a *note
     RuntimeError: 195. if called when there is no running event loop
     and the current event loop was not set.  Previously they implicitly
     created and set a new current event loop.  *note
     DeprecationWarning: 1a5. is no longer emitted if there is no
     running event loop but the current event loop was set.

   - gh-97966(23): On ‘uname_result’, restored expectation that
     ‘_fields’ and ‘_asdict’ would include all six properties including
     ‘processor’.

   - gh-98248(24): Provide informative error messages in *note
     struct.pack(): 12bd. when its integral arguments are not in range.

   - gh-98108(25): ‘zipfile.Path’ is now pickleable if its
     initialization parameters were pickleable (e.g.  for file system
     paths).

   - gh-98098(26): Created packages from zipfile and test_zipfile
     modules, separating ‘zipfile.Path’ functionality.

   - gh-82836(27): Fix *note is_private: 1757. properties in the *note
     ipaddress: 80. module.  Previously non-private networks (0.0.0.0/0)
     would return ‘True’ from this method; now they correctly return
     ‘False’.

   - gh-96828(28): Add an *note OP_ENABLE_KTLS: 18b2. option for
     enabling the use of the kernel TLS (kTLS). Patch by Illia Volochii.

   - gh-88863(29): To avoid apparent memory leaks when *note
     asyncio.open_connection(): b31. raises, break reference cycles
     generated by local exception and future instances (which has
     exception instance as its member var).  Patch by Dong Uk, Kang.

   - gh-91078(30): ‘TarFile.next()’ now returns ‘None’ when called on an
     empty tarfile.

   - bpo-47220(31): Document the optional 'callback' parameter of
     ‘WeakMethod’.  Patch by Géry Ogam.

   - bpo-44817(32): Ignore WinError 53 (ERROR_BAD_NETPATH), 65
     (ERROR_NETWORK_ACCESS_DENIED) and 161 (ERROR_BAD_PATHNAME) when
     using ntpath.realpath().

   - bpo-41260(33): Rename the 'fmt' parameter of the pure Python
     implementation of *note datetime.date.strftime(): cb6. to 'format'.

   - bpo-15999(34): All built-in functions now accept arguments of any
     type instead of just ‘bool’ and ‘int’ for boolean parameters.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/100001

   (2) https://github.com/python/cpython/issues/99957

   (3) https://github.com/python/cpython/issues/79033

   (4) https://github.com/python/cpython/issues/51524

   (5) https://github.com/python/cpython/issues/99645

   (6) https://github.com/python/cpython/issues/99508

   (7) https://github.com/python/cpython/issues/66285

   (8) https://github.com/python/cpython/issues/97001

   (9) https://github.com/python/cpython/issues/92647

   (10) https://github.com/python/cpython/issues/99388

   (11) https://github.com/python/cpython/issues/99341

   (12) https://github.com/python/cpython/issues/99382

   (13) https://github.com/python/cpython/issues/99379

   (14) https://github.com/python/cpython/issues/99344

   (15) https://github.com/python/cpython/issues/99284

   (16) https://github.com/python/cpython/issues/99201

   (17) https://github.com/python/cpython/issues/99240

   (18) https://github.com/python/cpython/issues/64490

   (19) https://github.com/python/cpython/issues/99029

   (20) https://github.com/python/cpython/issues/98253

   (21) https://github.com/python/cpython/issues/98458

   (22) https://github.com/python/cpython/issues/93453

   (23) https://github.com/python/cpython/issues/97966

   (24) https://github.com/python/cpython/issues/98248

   (25) https://github.com/python/cpython/issues/98108

   (26) https://github.com/python/cpython/issues/98098

   (27) https://github.com/python/cpython/issues/82836

   (28) https://github.com/python/cpython/issues/96828

   (29) https://github.com/python/cpython/issues/88863

   (30) https://github.com/python/cpython/issues/91078

   (31) https://bugs.python.org/issue?@action=redirect&bpo=47220

   (32) https://bugs.python.org/issue?@action=redirect&bpo=44817

   (33) https://bugs.python.org/issue?@action=redirect&bpo=41260

   (34) https://bugs.python.org/issue?@action=redirect&bpo=15999


File: python.info,  Node: Documentation<24>,  Next: Tests<27>,  Prev: Library<52>,  Up: Python 3 12 0 alpha 3

1.23.33.6 Documentation
.......................

   - gh-99931(1): Use sphinxext-opengraph(2) to generate OpenGraph
     metadata(3).

   - gh-89682(4): Reworded docstring of the default ‘__contains__’ to
     clarify that it returns a *note bool: 46b.

   - gh-88330(5): Improved the description of what a resource is in
     importlib.resources docs.

   - gh-92892(6): Document that calling variadic functions with ctypes
     requires special care on macOS/arm64 (and possibly other
     platforms).

   - bpo-41825(7): Restructured the documentation for the *note
     os.wait*: dc6. family of functions, and improved the docs for *note
     os.waitid(): dc7. with more explanation of the possible argument
     constants.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99931

   (2) https://sphinxext-opengraph.readthedocs.io/

   (3) https://ogp.me/

   (4) https://github.com/python/cpython/issues/89682

   (5) https://github.com/python/cpython/issues/88330

   (6) https://github.com/python/cpython/issues/92892

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41825


File: python.info,  Node: Tests<27>,  Next: Build<28>,  Prev: Documentation<24>,  Up: Python 3 12 0 alpha 3

1.23.33.7 Tests
...............

   - gh-99892(1): Skip test_normalization() of test_unicodedata if it
     fails to download NormalizationTest.txt file from pythontest.net.
     Patch by Victor Stinner.

   - gh-99934(2): Correct test_marsh on (32 bit) x86: test_deterministic
     sets was failing.

   - gh-99741(3): We’ve implemented multi-phase init (PEP 489/630/687)
     for the internal (for testing) _xxsubinterpreters module.

   - gh-99659(4): Optional big memory tests in ‘test_sqlite3’ now catch
     the correct ‘sqlite.DataError’ exception type in case of too large
     strings and/or blobs passed.

   - gh-99593(5): Cover the Unicode C API with tests.

   - gh-96002(6): Add functional test for Argument Clinic.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99892

   (2) https://github.com/python/cpython/issues/99934

   (3) https://github.com/python/cpython/issues/99741

   (4) https://github.com/python/cpython/issues/99659

   (5) https://github.com/python/cpython/issues/99593

   (6) https://github.com/python/cpython/issues/96002


File: python.info,  Node: Build<28>,  Next: Windows<25>,  Prev: Tests<27>,  Up: Python 3 12 0 alpha 3

1.23.33.8 Build
...............

   - gh-99086(1): Fix ‘-Wimplicit-int’, ‘-Wstrict-prototypes’, and
     ‘-Wimplicit-function-declaration’ compiler warnings in ‘configure’
     checks.

   - gh-99337(2): Fix a compilation issue with GCC 12 on macOS.

   - gh-99289(3): Add a ‘COMPILEALL_OPTS’ variable in Makefile to
     override *note compileall: 20. options (default: ‘-j0’) in ‘make
     install’.  Also merged the ‘compileall’ commands into a single
     command building .pyc files for the all optimization levels (0, 1,
     2) at once.  Patch by Victor Stinner.

   - gh-98872(4): Fix a possible fd leak in ‘Programs/_freeze_module.c’
     introduced in Python 3.11.

   - gh-88226(5): Always define ‘TARGET_*’ labels in ‘Python/ceval.c’,
     even if ‘USE_COMPUTED_GOTOS’ is disabled.  This allows breakpoints
     to be set at those labels in (for instance) ‘gdb’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99086

   (2) https://github.com/python/cpython/issues/99337

   (3) https://github.com/python/cpython/issues/99289

   (4) https://github.com/python/cpython/issues/98872

   (5) https://github.com/python/cpython/issues/88226


File: python.info,  Node: Windows<25>,  Next: macOS<18>,  Prev: Build<28>,  Up: Python 3 12 0 alpha 3

1.23.33.9 Windows
.................

   - gh-99345(1): Use faster initialization functions to detect install
     location for Windows Store package

   - gh-98629(2): Fix initialization of *note sys.version: 178. and
     ‘sys._git’ on Windows

   - gh-99442(3): Fix handling in *note Python Launcher for Windows:
     5c1. when ‘argv[0]’ does not include a file extension.

   - bpo-40882(4): Fix a memory leak in *note
     multiprocessing.shared_memory.SharedMemory: 176c. on Windows.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99345

   (2) https://github.com/python/cpython/issues/98629

   (3) https://github.com/python/cpython/issues/99442

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40882


File: python.info,  Node: macOS<18>,  Next: Tools/Demos<16>,  Prev: Windows<25>,  Up: Python 3 12 0 alpha 3

1.23.33.10 macOS
................

   - gh-87235(1): On macOS ‘python3 /dev/fd/9 9</path/to/script.py’
     failed for any script longer than a couple of bytes.

   - gh-98940(2): Fix ‘Mac/Extras.install.py’ file filter bug.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87235

   (2) https://github.com/python/cpython/issues/98940


File: python.info,  Node: Tools/Demos<16>,  Next: C API<26>,  Prev: macOS<18>,  Up: Python 3 12 0 alpha 3

1.23.33.11 Tools/Demos
......................

   - gh-64490(1): Argument Clinic varargs bugfixes

        * Fix out-of-bounds error in
          ‘_PyArg_UnpackKeywordsWithVararg()’.

        * Fix incorrect check which allowed more than one varargs in
          clinic.py.

        * Fix miscalculation of ‘noptargs’ in generated code.

        * Do not generate ‘noptargs’ when there is a vararg argument and
          no optional argument.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/64490


File: python.info,  Node: C API<26>,  Prev: Tools/Demos<16>,  Up: Python 3 12 0 alpha 3

1.23.33.12 C API
................

   - gh-98680(1): ‘PyBUF_*’ constants were marked as part of Limited API
     of Python 3.11+.  These were available in 3.11.0 with *note
     Py_LIMITED_API: 421. defined for 3.11, and are necessary to use the
     buffer API.

   - gh-99612(2): Fix *note PyUnicode_DecodeUTF8Stateful(): 18ba. for
     ASCII-only data: ‘*consumed’ was not set.

   - gh-47146(3): The ‘structmember.h’ header is deprecated.  Its
     non-deprecated contents are now available just by including
     ‘Python.h’, with a ‘Py_’ prefix added if it was missing.
     (Deprecated contents are *note T_OBJECT: 596, *note T_NONE: 598,
     and no-op flags.)  Patch by Petr Viktorin, based on earlier work by
     Alexander Belopolsky and Matthias Braun.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98680

   (2) https://github.com/python/cpython/issues/99612

   (3) https://github.com/python/cpython/issues/47146


File: python.info,  Node: Python 3 12 0 alpha 2,  Next: Python 3 12 0 alpha 1,  Prev: Python 3 12 0 alpha 3,  Up: Changelog

1.23.34 Python 3.12.0 alpha 2
-----------------------------

'Release date: 2022-11-14'

* Menu:

* Security: Security<23>.
* Core and Builtins: Core and Builtins<49>.
* Build: Build<29>.
* Core and Builtins: Core and Builtins<50>.
* Library: Library<53>.
* Documentation: Documentation<25>.
* Tests: Tests<28>.
* Build: Build<30>.
* Windows: Windows<26>.
* macOS: macOS<19>.
* C API: C API<27>.


File: python.info,  Node: Security<23>,  Next: Core and Builtins<49>,  Up: Python 3 12 0 alpha 2

1.23.34.1 Security
..................

   - gh-98433(1): The IDNA codec decoder used on DNS hostnames by *note
     socket: cc. or *note asyncio: a. related name resolution functions
     no longer involves a quadratic algorithm.  This prevents a
     potential CPU denial of service if an out-of-spec excessive length
     hostname involving bidirectional characters were decoded.  Some
     protocols such as *note urllib: 108. http ‘3XX’ redirects
     potentially allow for an attacker to supply such a name.

     Individual labels within an IDNA encoded DNS name will now raise an
     error early during IDNA decoding if they are longer than 1024
     unicode characters given that each decoded DNS label must be 63 or
     fewer characters and the entire decoded DNS name is limited to 255.
     Only an application presenting a hostname or label consisting
     primarily of RFC 3454(2) section 3.1 “Nothing” characters to be
     removed would run into of this new limit.  See also RFC 5894(3)
     section 6 and RFC 3491(4).

   - gh-98739(5): Update bundled libexpat to 2.5.0

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98433

   (2) https://datatracker.ietf.org/doc/html/rfc3454.html

   (3) https://datatracker.ietf.org/doc/html/rfc5894.html

   (4) https://datatracker.ietf.org/doc/html/rfc3491.html

   (5) https://github.com/python/cpython/issues/98739


File: python.info,  Node: Core and Builtins<49>,  Next: Build<29>,  Prev: Security<23>,  Up: Python 3 12 0 alpha 2

1.23.34.2 Core and Builtins
...........................

   - gh-81057(1): The docs clearly say that *note PyImport_Inittab:
     18be, *note PyImport_AppendInittab(): 18bf, and *note
     PyImport_ExtendInittab(): 18c0. should not be used after *note
     Py_Initialize(): 8b4. has been called.  We now enforce this for the
     two functions.  Additionally, the runtime now uses an internal copy
     of ‘PyImport_Inittab’, to guard against modification.

   - gh-99298(2): Fix an issue that could potentially cause incorrect
     error handling for some bytecode instructions.

   - gh-99254(3): The compiler now removes all unused constants from
     code objects (except the first one, which may be a docstring).

   - gh-99205(4): Fix an issue that prevented *note PyThreadState: 790.
     and *note PyInterpreterState: 8c5. memory from being freed
     properly.

   - gh-81057(5): The 18 global C variables holding the state of the
     allocators have been moved to ‘_PyRuntimeState’.  This is a
     strictly internal change with no change in behavior.

   - gh-99181(6): Fix failure in *note except*: 5bb. with unhashable
     exceptions.

   - gh-99204(7): Fix calculation of ‘sys._base_executable’ when inside
     a POSIX virtual environment using copies of the python binary when
     the base installation does not provide the executable name used by
     the venv.  Calculation will fall back to alternative names
     (“python<MAJOR>”, “python<MAJOR>.<MINOR>”).

   - gh-96055(8): Update *note faulthandler: 58. to emit an error
     message with the proper unexpected signal number.  Patch by Donghee
     Na.

   - gh-99153(9): Fix location of *note SyntaxError: 18d. for a *note
     try: 6ec. block with both *note except: 18b. and *note except*:
     5bb.

   - gh-98686(10): Merge the adaptive opcode logic into each
     instruction’s unquickened variant, and merge the logic in
     ‘EXTENDED_ARG_QUICK’ into *note EXTENDED_ARG: 18c1.  With these
     changes, the quickening that happens at code object creation is now
     only responsible for initializing warmup counters and inserting
     superinstructions.

   - gh-99103(11): Fix the error reporting positions of specialized
     traceback anchors when the source line contains Unicode characters.

   - gh-99139(12): Improve the error suggestion for *note NameError:
     442. exceptions for instances.  Now if a ‘NameError’ is raised in a
     method and the instance has an attribute that’s exactly equal to
     the name in the exception, the suggestion will include
     ‘self.<NAME>’ instead of the closest match in the method scope.
     Patch by Pablo Galindo

   - gh-98401(13): Octal escapes with value larger than ‘0o377’ (ex:
     ‘"\477"’), deprecated in Python 3.11, now produce a *note
     SyntaxWarning: 469, instead of *note DeprecationWarning: 1a5.  In a
     future Python version they will be eventually a *note SyntaxError:
     18d.  Patch by Victor Stinner.

   - gh-98401(14): A backslash-character pair that is not a valid escape
     sequence now generates a *note SyntaxWarning: 469, instead of *note
     DeprecationWarning: 1a5.  For example, ‘re.compile("\d+\.\d+")’ now
     emits a ‘SyntaxWarning’ (‘"\d"’ is an invalid escape sequence), use
     raw strings for regular expression: ‘re.compile(r"\d+\.\d+")’.  In
     a future Python version, *note SyntaxError: 18d. will eventually be
     raised, instead of ‘SyntaxWarning’.  Patch by Victor Stinner.

   - gh-96793(15): Handle StopIteration and StopAsyncIteration raised in
     generator or coroutines in the bytecode, rather than in wrapping C
     code.

   - gh-98931(16): Improve the *note SyntaxError: 18d. error message
     when the user types ‘import x from y’ instead of ‘from y import x’.
     Patch by Pablo Galindo

   - gh-98852(17): Fix subscription of type aliases containing bare
     generic types or types like *note TypeVar: 15d.: for example
     ‘tuple[A, T][int]’ and ‘tuple[TypeVar, T][int]’, where ‘A’ is a
     generic type, and ‘T’ is a type variable.

   - gh-98925(18): Lower the recursion depth for marshal on WASI to
     support (in-development) wasmtime 2.0.

   - gh-98783(19): Fix multiple crashes in debug mode when ‘str’
     subclasses are used instead of ‘str’ itself.

   - gh-98811(20): Use complete source locations to simplify detection
     of ‘__future__’ imports which are not at the beginning of the file.
     Also corrects the offset in the exception raised in one case, which
     was off by one and impeded highlighting.

   - gh-96793(21): Add specialization of *note FOR_ITER: 1866. for
     generators.  Saves multiple layers of dispatch and checking to get
     from the ‘FOR_ITER’ instruction in the caller to the *note RESUME:
     315. in the generator.

   - gh-98762(22): Fix source locations of *note match: 813.
     sub-patterns.

   - gh-98586(23): Added the methods *note PyObject_Vectorcall(): 55f.
     and *note PyObject_VectorcallMethod(): 560. to the *note Limited
     API: 556. along with the auxiliary macro constant *note
     PY_VECTORCALL_ARGUMENTS_OFFSET: 561.

     The availability of these functions enables more efficient PEP
     590(24) vector calls from binary extension modules that avoid
     argument boxing/unboxing overheads.

   - gh-99257(25): Fix an issue where member descriptors (such as those
     for *note __slots__: 153a.) could behave incorrectly or crash
     instead of raising a *note TypeError: 2c3. when accessed via an
     instance of an invalid type.

   - gh-93143(26): Rather than changing ‘co_code’, the interpreter will
     now display a *note RuntimeWarning: 1bd. and assign *note None:
     678. to any fast locals that are left unbound after jumps or *note
     del: 18c2. statements executed while tracing.

   - gh-96421(27): When calling into Python code from C code, through
     *note PyEval_EvalFrameEx(): 106b. or a related C-API function, a
     shim frame in inserted into the call stack.  This occurs in the
     ‘_PyEval_EvalFrameDefault()’ function.  The extra frame should be
     invisible to all Python and most C extensions, but out-of-process
     profilers and debuggers need to be aware of it.  These shim frames
     can be detected by checking ‘frame->owner ==
     FRAME_OWNED_BY_CSTACK’.

     Extensions implementing their own interpreters using PEP 523 need
     to be aware of this shim frame and the changes to the semantics of
     *note RETURN_VALUE: 18c3, *note YIELD_VALUE: 314, and *note
     RETURN_GENERATOR: 6ff, which now clear the frame.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/81057

   (2) https://github.com/python/cpython/issues/99298

   (3) https://github.com/python/cpython/issues/99254

   (4) https://github.com/python/cpython/issues/99205

   (5) https://github.com/python/cpython/issues/81057

   (6) https://github.com/python/cpython/issues/99181

   (7) https://github.com/python/cpython/issues/99204

   (8) https://github.com/python/cpython/issues/96055

   (9) https://github.com/python/cpython/issues/99153

   (10) https://github.com/python/cpython/issues/98686

   (11) https://github.com/python/cpython/issues/99103

   (12) https://github.com/python/cpython/issues/99139

   (13) https://github.com/python/cpython/issues/98401

   (14) https://github.com/python/cpython/issues/98401

   (15) https://github.com/python/cpython/issues/96793

   (16) https://github.com/python/cpython/issues/98931

   (17) https://github.com/python/cpython/issues/98852

   (18) https://github.com/python/cpython/issues/98925

   (19) https://github.com/python/cpython/issues/98783

   (20) https://github.com/python/cpython/issues/98811

   (21) https://github.com/python/cpython/issues/96793

   (22) https://github.com/python/cpython/issues/98762

   (23) https://github.com/python/cpython/issues/98586

   (24) https://peps.python.org/pep-0590/

   (25) https://github.com/python/cpython/issues/99257

   (26) https://github.com/python/cpython/issues/93143

   (27) https://github.com/python/cpython/issues/96421


File: python.info,  Node: Build<29>,  Next: Core and Builtins<50>,  Prev: Core and Builtins<49>,  Up: Python 3 12 0 alpha 2

1.23.34.3 Build
...............

   - gh-98415(1): Fix detection of MAC addresses for *note uuid: 110. on
     certain OSs.  Patch by Chaim Sanders

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98415


File: python.info,  Node: Core and Builtins<50>,  Next: Library<53>,  Prev: Build<29>,  Up: Python 3 12 0 alpha 2

1.23.34.4 Core and Builtins
...........................

   - gh-98686(1): Quicken all code objects, and specialize adaptive
     bytecode instructions more aggressively.

   - gh-92119(2): Print exception class name instead of its string
     representation when raising errors from *note ctypes: 2a. calls.

   - gh-91058(3): *note ImportError: 41c. raised from failed ‘from
     <module> import <name>’ now include suggestions for the value of
     ‘<name>’ based on the available names in ‘<module>’.  Patch by
     Pablo Galindo

   - gh-96793(4): The *note FOR_ITER: 1866. now leaves the iterator on
     the stack on termination of the loop.  This is to assist
     specialization of loops for generators.

   - gh-90716(5): Add _pylong.py module.  It includes asymptotically
     faster algorithms that can be used for operations on integers with
     many digits.  It is used by longobject.c to speed up some
     operations.

   - gh-95389(6): Expose *note ETH_P_ALL: 18c6. and some of the *note
     ETHERTYPE_* constants: 18c7. in *note socket: cc.  Patch by Noam
     Cohen.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98686

   (2) https://github.com/python/cpython/issues/92119

   (3) https://github.com/python/cpython/issues/91058

   (4) https://github.com/python/cpython/issues/96793

   (5) https://github.com/python/cpython/issues/90716

   (6) https://github.com/python/cpython/issues/95389


File: python.info,  Node: Library<53>,  Next: Documentation<25>,  Prev: Core and Builtins<50>,  Up: Python 3 12 0 alpha 2

1.23.34.5 Library
.................

   - gh-93696(1): Allow *note pdb: a5. to locate source for frozen
     modules in the standard library.

   - gh-99418(2): Fix bug in *note urllib.parse.urlparse(): 30d. that
     causes URL schemes that begin with a digit, a plus sign, or a minus
     sign to be parsed incorrectly.

   - gh-94597(3): Deprecate *note asyncio.AbstractChildWatcher: 2bc. to
     be removed in Python 3.14.  Patch by Kumar Aditya.

   - gh-99305(4): Improve performance of *note secrets.token_hex():
     18c9.

   - gh-74044(5): Fixed bug where *note inspect.signature(): 73b.
     reported incorrect arguments for decorated methods.

   - gh-99275(6): Fix ‘SystemError’ in *note ctypes: 2a. when exception
     was not set during ‘__initsubclass__’.

   - gh-99277(7): Remove older version of
     ‘_SSLProtocolTransport.get_write_buffer_limits’ in
     ‘asyncio.sslproto’

   - gh-99248(8): fix negative numbers failing in verify()

   - gh-99155(9): Fix *note statistics.NormalDist: a45. pickle with ‘0’
     and ‘1’ protocols.

   - gh-93464(10): ‘enum.auto()’ is now correctly activated when
     combined with other assignment values.  E.g.  ‘ONE = auto(), 'some
     text'’ will now evaluate as ‘(1, 'some text')’.

   - gh-99134(11): Update the bundled copy of pip to version 22.3.1.

   - gh-92584(12): Remove the ‘distutils’ package.  It was deprecated in
     Python 3.10 by PEP 632(13) “Deprecate distutils module”.  For
     projects still using ‘distutils’ and cannot be updated to something
     else, the ‘setuptools’ project can be installed: it still provides
     ‘distutils’.  Patch by Victor Stinner.

   - gh-98999(14): Now ‘_pyio’ is consistent with ‘_io’ in raising
     ‘ValueError’ when executing methods over closed buffers.

   - gh-83004(15): Clean up refleak on failed module initialisation in
     ‘_zoneinfo’

   - gh-83004(16): Clean up refleaks on failed module initialisation in
     ‘_pickle’

   - gh-83004(17): Clean up refleak on failed module initialisation in
     ‘_io’.

   - gh-98897(18): Fix memory leak in *note math.dist(): a0d. when both
     points don’t have the same dimension.  Patch by Kumar Aditya.

   - gh-98878(19): Use the frame bound builtins when offering a name
     suggestion in *note traceback: fe. to prevent crashing when
     ‘__builtins__’ is not a dict.

   - gh-98139(20): In ‘importlib._bootstrap’, enhance namespace package
     repr to ‘<module 'x' (namespace) from ['path']>’.

   - gh-90352(21): Fix ‘_SelectorDatagramTransport’ to inherit from
     *note DatagramTransport: 18ca. in *note asyncio: a.  Patch by Kumar
     Aditya.

   - gh-98793(22): Fix argument typechecks in ‘_overlapped.WSAConnect()’
     and ‘_overlapped.Overlapped.WSASendTo()’ functions.

   - gh-98744(23): Prevent crashing in *note traceback: fe. when
     retrieving the byte-offset for some source files that contain
     certain unicode characters.

   - gh-98740(24): Fix internal error in the *note re: b9. module which
     in very rare circumstances prevented compilation of a regular
     expression containing a *note conditional expression: 18cb. without
     the “else” branch.

   - gh-98703(25): Fix *note asyncio.StreamWriter.drain(): 18cc. to call
     ‘protocol.connection_lost’ callback only once on Windows.

   - gh-98624(26): Add a mutex to unittest.mock.NonCallableMock to
     protect concurrent access to mock attributes.

   - gh-98658(27): The *note array.array: 1a0. class now supports
     subscripting, making it a *note generic type: 43c.

   - gh-98284(28): Improved *note TypeError: 2c3. message for undefined
     abstract methods of a *note abc.ABC: f4e. instance.  The names of
     the missing methods are surrounded by single-quotes to highlight
     them.

   - gh-96151(29): Allow ‘BUILTINS’ to be a valid field name for frozen
     dataclasses.

   - gh-98086(30): Make sure ‘patch.dict()’ can be applied on async
     functions.

   - gh-72719(31): Remove modules ‘asyncore’ and ‘asynchat’, which were
     deprecated by PEP 594(32).

   - gh-96192(33): Fix handling of ‘bytes’ *note path-like objects: 2a0.
     in ‘os.ismount()’.

   - gh-94172(34): *note ftplib: 5e.: Remove the ‘FTP_TLS.ssl_version’
     class attribute: use the 'context' parameter instead.  Patch by
     Victor Stinner

   - gh-94172(35): Remove the 'keyfile' and 'certfile' parameters from
     the *note ftplib: 5e, *note imaplib: 74, *note poplib: ac. and
     *note smtplib: ca. modules, and the 'key_file', 'cert_file' and
     'check_hostname' parameters from the *note http.client: 6f. module,
     all deprecated since Python 3.6.  Use the 'context' parameter
     ('ssl_context' in ‘imaplib’) instead.  Patch by Victor Stinner.

   - gh-83638(36): Add the *note autocommit: 4b9. attribute to *note
     sqlite3.Connection: 245. and the 'autocommit' parameter to *note
     sqlite3.connect(): 2a8. to control PEP 249(37)-compliant *note
     transaction handling: 4ba.  Patch by Erlend E. Aasland.

   - gh-92452(38): Fixed a race condition that could cause *note
     sysconfig.get_config_var(): 1068. to incorrectly return *note None:
     678. in multi-threaded programs.

   - gh-91803(39): Fix an error when using a method of objects mocked
     with *note unittest.mock.create_autospec(): 1712. after it was
     sealed with *note unittest.mock.seal(): bbf. function.

   - bpo-38523(40): *note shutil.copytree(): a36. now applies the
     'ignore_dangling_symlinks' argument recursively.

   - bpo-40358(41): Add walk_up argument in *note
     pathlib.PurePath.relative_to(): 2ca.

   - bpo-36267(42): Fix IndexError in *note argparse.ArgumentParser:
     53c. when a ‘store_true’ action is given an explicit argument.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93696

   (2) https://github.com/python/cpython/issues/99418

   (3) https://github.com/python/cpython/issues/94597

   (4) https://github.com/python/cpython/issues/99305

   (5) https://github.com/python/cpython/issues/74044

   (6) https://github.com/python/cpython/issues/99275

   (7) https://github.com/python/cpython/issues/99277

   (8) https://github.com/python/cpython/issues/99248

   (9) https://github.com/python/cpython/issues/99155

   (10) https://github.com/python/cpython/issues/93464

   (11) https://github.com/python/cpython/issues/99134

   (12) https://github.com/python/cpython/issues/92584

   (13) https://peps.python.org/pep-0632/

   (14) https://github.com/python/cpython/issues/98999

   (15) https://github.com/python/cpython/issues/83004

   (16) https://github.com/python/cpython/issues/83004

   (17) https://github.com/python/cpython/issues/83004

   (18) https://github.com/python/cpython/issues/98897

   (19) https://github.com/python/cpython/issues/98878

   (20) https://github.com/python/cpython/issues/98139

   (21) https://github.com/python/cpython/issues/90352

   (22) https://github.com/python/cpython/issues/98793

   (23) https://github.com/python/cpython/issues/98744

   (24) https://github.com/python/cpython/issues/98740

   (25) https://github.com/python/cpython/issues/98703

   (26) https://github.com/python/cpython/issues/98624

   (27) https://github.com/python/cpython/issues/98658

   (28) https://github.com/python/cpython/issues/98284

   (29) https://github.com/python/cpython/issues/96151

   (30) https://github.com/python/cpython/issues/98086

   (31) https://github.com/python/cpython/issues/72719

   (32) https://peps.python.org/pep-0594/

   (33) https://github.com/python/cpython/issues/96192

   (34) https://github.com/python/cpython/issues/94172

   (35) https://github.com/python/cpython/issues/94172

   (36) https://github.com/python/cpython/issues/83638

   (37) https://peps.python.org/pep-0249/

   (38) https://github.com/python/cpython/issues/92452

   (39) https://github.com/python/cpython/issues/91803

   (40) https://bugs.python.org/issue?@action=redirect&bpo=38523

   (41) https://bugs.python.org/issue?@action=redirect&bpo=40358

   (42) https://bugs.python.org/issue?@action=redirect&bpo=36267


File: python.info,  Node: Documentation<25>,  Next: Tests<28>,  Prev: Library<53>,  Up: Python 3 12 0 alpha 2

1.23.34.6 Documentation
.......................

   - gh-98832(1): Changes wording of docstring for *note
     pathlib.Path.iterdir(): 173a.

   - gh-97966(2): Update uname docs to clarify the special nature of the
     platform attribute and to indicate when it became late-bound.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98832

   (2) https://github.com/python/cpython/issues/97966


File: python.info,  Node: Tests<28>,  Next: Build<30>,  Prev: Documentation<25>,  Up: Python 3 12 0 alpha 2

1.23.34.7 Tests
...............

   - gh-98903(1): The Python test suite now fails with exit code 4 if no
     tests ran.  It should help detecting typos in test names and test
     methods.

   - gh-98713(2): Fix a bug in the *note typing: 104. tests where a test
     relying on CPython-specific implementation details was not
     decorated with ‘@cpython_only’ and was not skipped on other
     implementations.

   - gh-87390(3): Add tests for star-unpacking with PEP 646, and some
     other miscellaneous PEP 646 tests.

   - gh-96853(4): Added explicit coverage of ‘Py_Initialize’ (and hence
     ‘Py_InitializeEx’) back to the embedding tests (all other embedding
     tests migrated to ‘Py_InitializeFromConfig’ in Python 3.11)

   - bpo-34272(5): Some C API tests were moved into the new
     Lib/test/test_capi/ directory.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98903

   (2) https://github.com/python/cpython/issues/98713

   (3) https://github.com/python/cpython/issues/87390

   (4) https://github.com/python/cpython/issues/96853

   (5) https://bugs.python.org/issue?@action=redirect&bpo=34272


File: python.info,  Node: Build<30>,  Next: Windows<26>,  Prev: Tests<28>,  Up: Python 3 12 0 alpha 2

1.23.34.8 Build
...............

   - gh-99086(1): Fix ‘-Wimplicit-int’ compiler warning in ‘configure’
     check for ‘PTHREAD_SCOPE_SYSTEM’.

   - gh-99016(2): Fix build with ‘PYTHON_FOR_REGEN=python3.8’.

   - gh-97731(3): Specify the full path to the source location for ‘make
     docclean’ (needed for cross-builds).

   - gh-98949(4): Drop unused build dependency on ‘readelf’.

   - gh-98989(5): Use ‘python3.11’, if available, for regeneration and
     freezing.

   - gh-98831(6): Add new tooling, in ‘Tools/cases_generator’, to
     generate the interpreter switch statement from a list of opcode
     definitions.  This only affects adding, modifying or removing
     instruction definitions.  The instruction definitions now live in
     ‘Python/bytecodes.c’, in the form of a custom DSL (under
     development)(7).  The tooling reads this file and writes
     ‘Python/generated_cases.c.h’, which is then included by
     ‘Python/ceval.c’ to provide most of the cases of the main
     interpreter switch.

   - gh-98817(8): Remove PCbuild/lib.pyproj: it’s not used for anything,
     is only a minor convenience for Visual Studio users (who probably
     mostly don’t even know about it), and it takes a lot of maintenance
     effort to keep updated.

   - gh-98776(9): Fix ‘make regen-test-levenshtein’ for out-of-tree
     builds.

   - gh-98707(10): Don’t use vendored ‘libmpdec’ headers if *note
     -with-system-libmpdec: 415. is passed to ‘configure’.  Don’t use
     vendored ‘libexpat’ headers if *note -with-system-expat: 18d0. is
     passed to ‘configure’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/99086

   (2) https://github.com/python/cpython/issues/99016

   (3) https://github.com/python/cpython/issues/97731

   (4) https://github.com/python/cpython/issues/98949

   (5) https://github.com/python/cpython/issues/98989

   (6) https://github.com/python/cpython/issues/98831

   (7) 
https://github.com/faster-cpython/ideas/blob/main/3.12/interpreter_definition.md

   (8) https://github.com/python/cpython/issues/98817

   (9) https://github.com/python/cpython/issues/98776

   (10) https://github.com/python/cpython/issues/98707


File: python.info,  Node: Windows<26>,  Next: macOS<19>,  Prev: Build<30>,  Up: Python 3 12 0 alpha 2

1.23.34.9 Windows
.................

   - gh-98689(1): Update Windows builds to zlib v1.2.13.  v1.2.12 has
     CVE 2022-37434(2), but the vulnerable ‘inflateGetHeader’ API is not
     used by Python.

   - gh-98790(3): Assumes that a missing ‘DLLs’ directory means that
     standard extension modules are in the executable’s directory.

   - gh-98745(4): Update ‘py.exe’ launcher to install 3.11 by default
     and 3.12 on request.

   - gh-98692(5): Fix the *note Python Launcher for Windows: 5c1.
     ignoring unrecognized shebang lines instead of treating them as
     local paths

   - gh-94328(6): Update Windows installer to use SQLite 3.39.4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98689

   (2) https://www.cve.org/CVERecord?id=CVE-2022-37434

   (3) https://github.com/python/cpython/issues/98790

   (4) https://github.com/python/cpython/issues/98745

   (5) https://github.com/python/cpython/issues/98692

   (6) https://github.com/python/cpython/issues/94328


File: python.info,  Node: macOS<19>,  Next: C API<27>,  Prev: Windows<26>,  Up: Python 3 12 0 alpha 2

1.23.34.10 macOS
................

   - gh-94328(1): Update macOS installer to SQLite 3.39.4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94328


File: python.info,  Node: C API<27>,  Prev: macOS<19>,  Up: Python 3 12 0 alpha 2

1.23.34.11 C API
................

   - gh-98724(1): The *note Py_CLEAR: 57b, *note Py_SETREF: 57c. and
     *note Py_XSETREF: 57d. macros now only evaluate their argument
     once.  If the argument has side effects, these side effects are no
     longer duplicated.  Patch by Victor Stinner.

   - gh-98978(2): Fix use-after-free in ‘Py_SetPythonHome(NULL)’,
     ‘Py_SetProgramName(NULL)’ and ‘_Py_SetProgramFullPath(NULL)’
     function calls.  Issue reported by Benedikt Reinartz.  Patch by
     Victor Stinner.

   - gh-98410(3): Add ‘getbufferproc’ and ‘releasebufferproc’ to the
     stable API.

   - gh-98610(4): Some configurable capabilities of sub-interpreters
     have changed.  They always allow subprocesses (*note subprocess:
     d6.) now, whereas before subprocesses could be optionally
     disallowed for a sub-interpreter.  Instead ‘os.exec()’ can now be
     disallowed.  Disallowing daemon threads is now supported.
     Disallowing all threads is still allowed, but is never done by
     default.  Note that the optional restrictions are only available
     through ‘_Py_NewInterpreterFromConfig()’, which isn’t a public API.
     They do not affect the main interpreter, nor *note
     Py_NewInterpreter(): 18d4.

   - gh-98608(5): A ‘_PyInterpreterConfig’ has been added and
     ‘_Py_NewInterpreter()’ has been renamed to
     ‘_Py_NewInterpreterFromConfig()’.  The “isolated_subinterpreters”
     argument is now a granular config that captures the previous
     behavior.  Note that this is all “private” API.

   - gh-96853(6): ‘Py_InitializeEx’ now correctly calls ‘PyConfig_Clear’
     after initializing the interpreter (the omission didn’t cause a
     memory leak only because none of the dynamically allocated config
     fields are populated by the wrapper function)

   - gh-91248(7): Add *note PyFrame_GetVar(): 56b. and *note
     PyFrame_GetVarString(): 56c. functions to get a frame variable by
     its name.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98724

   (2) https://github.com/python/cpython/issues/98978

   (3) https://github.com/python/cpython/issues/98410

   (4) https://github.com/python/cpython/issues/98610

   (5) https://github.com/python/cpython/issues/98608

   (6) https://github.com/python/cpython/issues/96853

   (7) https://github.com/python/cpython/issues/91248


File: python.info,  Node: Python 3 12 0 alpha 1,  Next: Python 3 11 0 beta 1,  Prev: Python 3 12 0 alpha 2,  Up: Changelog

1.23.35 Python 3.12.0 alpha 1
-----------------------------

'Release date: 2022-10-25'

* Menu:

* Security: Security<24>.
* Core and Builtins: Core and Builtins<51>.
* Library: Library<54>.
* Core and Builtins: Core and Builtins<52>.
* Library: Library<55>.
* Core and Builtins: Core and Builtins<53>.
* Library: Library<56>.
* Core and Builtins: Core and Builtins<54>.
* Library: Library<57>.
* Core and Builtins: Core and Builtins<55>.
* Library: Library<58>.
* Core and Builtins: Core and Builtins<56>.
* Library: Library<59>.
* Core and Builtins: Core and Builtins<57>.
* Library: Library<60>.
* Core and Builtins: Core and Builtins<58>.
* Library: Library<61>.
* Core and Builtins: Core and Builtins<59>.
* Library: Library<62>.
* Core and Builtins: Core and Builtins<60>.
* Library: Library<63>.
* Documentation: Documentation<26>.
* Tests: Tests<29>.
* Build: Build<31>.
* Windows: Windows<27>.
* macOS: macOS<20>.
* IDLE: IDLE<19>.
* Tools/Demos: Tools/Demos<17>.
* C API: C API<28>.


File: python.info,  Node: Security<24>,  Next: Core and Builtins<51>,  Up: Python 3 12 0 alpha 1

1.23.35.1 Security
..................

   - gh-97616(1): Fix multiplying a list by an integer (‘list *= int’):
     detect the integer overflow when the new allocated length is close
     to the maximum size.  Issue reported by Jordan Limor.  Patch by
     Victor Stinner.

   - gh-97514(2): On Linux the *note multiprocessing: 94. module returns
     to using filesystem backed unix domain sockets for communication
     with the 'forkserver' process instead of the Linux abstract socket
     namespace.  Only code that chooses to use the *note “forkserver”
     start method: 2c8. is affected.

     Abstract sockets have no permissions and could allow any user on
     the system in the same network namespace(3) (often the whole
     system) to inject code into the multiprocessing 'forkserver'
     process.  This was a potential privilege escalation.  Filesystem
     based socket permissions restrict this to the 'forkserver' process
     user as was the default in Python 3.8 and earlier.

     This prevents Linux CVE 2022-42919(4).

   - gh-87389(5): *note http.server: 72.: Fix an open redirection
     vulnerability in the HTTP server when an URI path starts with ‘//’.
     Vulnerability discovered, and initial fix proposed, by Hamza Avvan.

   - gh-79096(6): LWPCookieJar and MozillaCookieJar create files with
     file mode 600 instead of 644 (Microsoft Windows is not affected)

   - gh-92888(7): Fix ‘memoryview’ use after free when accessing the
     backing buffer in certain cases.

   - gh-68966(8): The deprecated mailcap module now refuses to inject
     unsafe text (filenames, MIME types, parameters) into shell
     commands.  Instead of using such text, it will warn and act as if a
     match was not found (or for test commands, as if the test failed).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97616

   (2) https://github.com/python/cpython/issues/97514

   (3) https://man7.org/linux/man-pages/man7/network_namespaces.7.html

   (4) https://www.cve.org/CVERecord?id=CVE-2022-42919

   (5) https://github.com/python/cpython/issues/87389

   (6) https://github.com/python/cpython/issues/79096

   (7) https://github.com/python/cpython/issues/92888

   (8) https://github.com/python/cpython/issues/68966


File: python.info,  Node: Core and Builtins<51>,  Next: Library<54>,  Prev: Security<24>,  Up: Python 3 12 0 alpha 1

1.23.35.2 Core and Builtins
...........................

   - gh-98374(1): Suppress ImportError for invalid query for help()
     command.  Patch by Donghee Na.

   - gh-98461(2): Fix source location in bytecode for list, set and dict
     comprehensions as well as generator expressions.

   - gh-98354(3): Added unicode check for ‘name’ attribute of ‘spec’
     argument passed in ‘_imp.create_builtin()’ function.

   - gh-98398(4): Fix source location of ‘assert’ bytecodes.

   - gh-98390(5): Fix location of sub-expressions of boolean
     expressions, by reducing their scope to that of the sub-expression.

   - gh-98254(6): Modules from the standard library are now potentially
     suggested as part of the error messages displayed by the
     interpreter when an *note NameError: 442. is raised to the top
     level.  Patch by Pablo Galindo

   - gh-97997(7): Add running column offset to the tokenizer state to
     avoid calculating AST column information with pointer arithmetic.

   - gh-97973(8): Modify the tokenizer to return all necessary
     information the parser needs to set location information in the AST
     nodes, so that the parser does not have to calculate those doing
     pointer arithmetic.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98374

   (2) https://github.com/python/cpython/issues/98461

   (3) https://github.com/python/cpython/issues/98354

   (4) https://github.com/python/cpython/issues/98398

   (5) https://github.com/python/cpython/issues/98390

   (6) https://github.com/python/cpython/issues/98254

   (7) https://github.com/python/cpython/issues/97997

   (8) https://github.com/python/cpython/issues/97973


File: python.info,  Node: Library<54>,  Next: Core and Builtins<52>,  Prev: Core and Builtins<51>,  Up: Python 3 12 0 alpha 1

1.23.35.3 Library
.................

   - gh-96078(1): *note os.sched_yield(): 1155. now release the GIL
     while calling sched_yield(2).  Patch by Donghee Na.

   - gh-97955(2): Migrate *note zoneinfo: 134. to Argument Clinic.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96078

   (2) https://github.com/python/cpython/issues/97955


File: python.info,  Node: Core and Builtins<52>,  Next: Library<55>,  Prev: Library<54>,  Up: Python 3 12 0 alpha 1

1.23.35.4 Core and Builtins
...........................

   - gh-97912(1): The compiler now avoids quadratic behavior when
     finding which instructions should use the *note LOAD_FAST_CHECK:
     4e8. opcode.

   - gh-97002(2): Fix an issue where several frame objects could be
     backed by the same interpreter frame, possibly leading to corrupted
     memory and hard crashes of the interpreter.

   - gh-97943(3): Bugfix: *note PyFunction_GetAnnotations(): 18da.
     should return a borrowed reference.  It was returning a new
     reference.

   - gh-97922(4): The Garbage Collector now runs only on the eval
     breaker mechanism of the Python bytecode evaluation loop instead on
     object allocations.  The GC can also run when *note
     PyErr_CheckSignals(): 46a. is called so C extensions that need to
     run for a long time without executing any Python code also have a
     chance to execute the GC periodically.

   - gh-65961(5): When ‘__package__’ is different than
     ‘__spec__.parent’, raise a ‘DeprecationWarning’ instead of
     ‘ImportWarning’.

     Also remove ‘importlib.util.set_package()’ which was scheduled for
     removal.

   - gh-97850(6): Long deprecated, ‘module_repr()’ should now be
     completely eradicated.

   - gh-86298(7): In cases where ‘warnings.warn_explicit()’ consults the
     module’s loader, an ‘DeprecationWarning’ is issued when
     ‘m.__loader__’ differs from ‘m.__spec__.loader’.

   - gh-97779(8): Ensure that all Python frame objects are backed by
     “complete” frames.

   - gh-91052(9): Add API for subscribing to modification events on
     selected dictionaries.

   - gh-97752(10): Fix possible data corruption or crashes when
     accessing the ‘f_back’ member of newly-created generator or
     coroutine frames.

   - gh-97591(11): Fixed a missing incref/decref pair in
     ‘Exception.__setstate__()’.  Patch by Ofey Chan.

   - gh-97670(12): Remove the ‘sys.getdxp()’ function and the
     ‘Tools/scripts/analyze_dxp.py’ script.  DXP stands for “dynamic
     execution pairs”.  They were related to ‘DYNAMIC_EXECUTION_PROFILE’
     and ‘DXPAIRS’ macros which have been removed in Python 3.11.
     Python can now be built with *note ./configure -enable-pystats:
     18db. to gather statistics on Python opcodes.  Patch by Victor
     Stinner.

   - gh-94526(13): Fix the Python path configuration used to initialized
     *note sys.path: 3b7. at Python startup.  Paths are no longer
     encoded to UTF-8/strict to avoid encoding errors if it contains
     surrogate characters (bytes paths are decoded with the
     surrogateescape error handler).  Patch by Victor Stinner.

   - gh-96670(14): The parser now raises *note SyntaxError: 18d. when
     parsing source code containing null bytes.  Patch by Pablo Galindo

   - gh-96975(15): Fix a crash occurring when *note PyEval_GetFrame():
     18dc. is called while the topmost Python frame is in a
     partially-initialized state.

   - gh-96848(16): Fix command line parsing: reject *note -X
     int_max_str_digits: 176. option with no value (invalid) when the
     *note PYTHONINTMAXSTRDIGITS: 18dd. environment variable is set to a
     valid limit.  Patch by Victor Stinner.

   - gh-95921(17): Fix overly-broad source position information for
     chained comparisons used as branching conditions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97912

   (2) https://github.com/python/cpython/issues/97002

   (3) https://github.com/python/cpython/issues/97943

   (4) https://github.com/python/cpython/issues/97922

   (5) https://github.com/python/cpython/issues/65961

   (6) https://github.com/python/cpython/issues/97850

   (7) https://github.com/python/cpython/issues/86298

   (8) https://github.com/python/cpython/issues/97779

   (9) https://github.com/python/cpython/issues/91052

   (10) https://github.com/python/cpython/issues/97752

   (11) https://github.com/python/cpython/issues/97591

   (12) https://github.com/python/cpython/issues/97670

   (13) https://github.com/python/cpython/issues/94526

   (14) https://github.com/python/cpython/issues/96670

   (15) https://github.com/python/cpython/issues/96975

   (16) https://github.com/python/cpython/issues/96848

   (17) https://github.com/python/cpython/issues/95921


File: python.info,  Node: Library<55>,  Next: Core and Builtins<53>,  Prev: Core and Builtins<52>,  Up: Python 3 12 0 alpha 1

1.23.35.5 Library
.................

   - gh-96821(1): Fix undefined behaviour in ‘audioop.c’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96821


File: python.info,  Node: Core and Builtins<53>,  Next: Library<56>,  Prev: Library<55>,  Up: Python 3 12 0 alpha 1

1.23.35.6 Core and Builtins
...........................

   - gh-96821(1): Fix undefined behaviour in ‘_testcapimodule.c’.

   - gh-95778(2): When *note ValueError: 202. is raised if an integer is
     larger than the limit, mention the *note
     sys.set_int_max_str_digits(): 18e0. function in the error message.
     Patch by Victor Stinner.

   - gh-96387(3): At Python exit, sometimes a thread holding the GIL can
     wait forever for a thread (usually a daemon thread) which requested
     to drop the GIL, whereas the thread already exited.  To fix the
     race condition, the thread which requested the GIL drop now resets
     its request before exiting.  Issue discovered and analyzed by
     Mingliang ZHAO. Patch by Victor Stinner.

   - gh-96864(4): Fix a possible assertion failure, fatal error, or
     *note SystemError: 578. if a line tracing event raises an exception
     while opcode tracing is enabled.

   - gh-95778(5): The ‘PyLong_FromString’ function was refactored to
     make it more maintainable and extensible.

   - gh-96678(6): Fix undefined behaviour in C code of null pointer
     arithmetic.

   - gh-96754(7): Make sure that all frame objects created are created
     from valid interpreter frames.  Prevents the possibility of invalid
     frames in backtraces and signal handlers.

   - gh-90997(8): Improve the performance of reading and writing inline
     bytecode caches on some platforms.

   - gh-96751(9): Remove dead code from ‘CALL_FUNCTION_EX’ opcode.

   - gh-90751(10): *note memoryview: 2eb. now supports half-floats.
     Patch by Donghee Na and Antoine Pitrou.

   - gh-96678(11): Fix case of undefined behavior in ceval.c

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96821

   (2) https://github.com/python/cpython/issues/95778

   (3) https://github.com/python/cpython/issues/96387

   (4) https://github.com/python/cpython/issues/96864

   (5) https://github.com/python/cpython/issues/95778

   (6) https://github.com/python/cpython/issues/96678

   (7) https://github.com/python/cpython/issues/96754

   (8) https://github.com/python/cpython/issues/90997

   (9) https://github.com/python/cpython/issues/96751

   (10) https://github.com/python/cpython/issues/90751

   (11) https://github.com/python/cpython/issues/96678


File: python.info,  Node: Library<56>,  Next: Core and Builtins<54>,  Prev: Core and Builtins<53>,  Up: Python 3 12 0 alpha 1

1.23.35.7 Library
.................

   - gh-64373(1): Convert ‘_functools’ to argument clinic.

   - gh-96641(2): Do not expose ‘KeyWrapper’ in ‘_functools’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/64373

   (2) https://github.com/python/cpython/issues/96641


File: python.info,  Node: Core and Builtins<54>,  Next: Library<57>,  Prev: Library<56>,  Up: Python 3 12 0 alpha 1

1.23.35.8 Core and Builtins
...........................

   - gh-96636(1): Ensure that tracing, ‘sys.setrace()’, is turned on
     immediately.  In pre-release versions of 3.11, some tracing events
     might have been lost when turning on tracing in a ‘__del__’ method
     or interrupt.

   - gh-96572(2): Fix use after free in trace refs build mode.  Patch by
     Kumar Aditya.

   - gh-96611(3): When loading a file with invalid UTF-8 inside a
     multi-line string, a correct SyntaxError is emitted.

   - gh-96612(4): Make sure that incomplete frames do not show up in
     tracemalloc traces.

   - gh-90230(5): Fix compiler warnings and test failures when building
     with ‘--enable-pystats’.

   - gh-96587(6): Correctly raise ‘SyntaxError’ on exception groups (
     PEP 654(7)) on python versions prior to 3.11

   - gh-96569(8): Remove two cases of undefined behavior, by adding NULL
     checks.

   - gh-96582(9): Fix possible ‘NULL’ pointer dereference in
     ‘_PyThread_CurrentFrames’.  Patch by Kumar Aditya.

   - gh-91079(10): Separate Python recursion checking from C recursion
     checking which reduces the chance of C stack overflow and allows
     the recursion limit to be increased safely.

   - gh-93911(11): Fix an issue that could prevent *note LOAD_ATTR: 4e1.
     from specializing properly when accessing properties.

   - gh-96348(12): Emit a DeprecationWarning when *note throw(): 4fb,
     *note throw(): 4fa. or *note athrow(): 4fc. are called with more
     than one argument.

   - gh-95196(13): Disable incorrect pickling of the C implemented
     classmethod descriptors.

   - gh-96364(14): Fix text signatures of ‘list.__getitem__’ and
     ‘dict.__getitem__’.

   - gh-96352(15): Fix *note AttributeError: 34e. missing ‘name’ and
     ‘obj’ attributes in *note object.__getattribute__(): bf1.  Patch by
     Philip Georgi.

   - gh-93554(16): Change the jump opcodes so that all conditional jumps
     are forward jumps.  Backward jumps are converted by the assembler
     into a conditional forward jump whose target is the fallthrough
     block (and with a reversed condition), followed by an unconditional
     backward jump.  For example:

     ‘POP_JUMP_IF_TRUE BACKWARD_TARGET’ becomes ‘POP_JUMP_IF_FALSE
     NEXT_BLOCK; JUMP BACKWARD_TARGET’.

     All the directed conditional jump opcodes were removed:
     ‘POP_JUMP_FORWARD_IF_TRUE’, ‘POP_JUMP_BACKWARD_IF_TRUE’,
     ‘POP_JUMP_FORWARD_IF_FALSE’, ‘POP_JUMP_BACKWARD_IF_FALSE’,
     ‘POP_JUMP_FORWARD_IF_NONE’, ‘POP_JUMP_BACKWARD_IF_NONE’,
     ‘POP_JUMP_FORWARD_IF_NOT_NONE’, ‘POP_JUMP_BACKWARD_IF_NOT_NONE’.

     The corresponding opcodes without direction are no longer
     pseudo-instructions, and they implement the forward conditional
     jumps.

   - gh-96268(17): Loading a file with invalid UTF-8 will now report the
     broken character at the correct location.

   - gh-96237(18): The internal field ‘_PyInterpreterFrame.f_func’ is
     renamed to ‘_PyInterpreterFrame.f_funcobj’ and may be any object.
     The ‘f_globals’ and ‘f_builtin’ fields may hold junk values.

     It is safest to treat the ‘_PyInterpreterFrame’ struct as opaque.

   - gh-96187(19): Fixed a bug that caused ‘_PyCode_GetExtra’ to return
     garbage for negative indexes.  Patch by Pablo Galindo

   - gh-96143(20): Add a new ‘-X perf’ Python command line option as
     well as *note sys.activate_stack_trampoline(): 472. and *note
     sys.deactivate_stack_trampoline(): 473. function in the *note sys:
     d9. module that allows to set/unset the interpreter in a way that
     the Linux ‘perf’ profiler can detect Python calls.  The new *note
     sys.is_stack_trampoline_active(): 474. function allows to query the
     state of the perf trampoline.  Design by Pablo Galindo.  Patch by
     Pablo Galindo and Christian Heimes with contributions from Gregory
     P. Smith [Google] and Mark Shannon.

   - gh-96071(21): Fix a deadlock in *note PyGILState_Ensure(): 3ae.
     when allocating new thread state.  Patch by Kumar Aditya.

   - gh-96046(22): *note PyType_Ready(): 77f. now initializes
     ‘ht_cached_keys’ and performs additional checks to ensure that type
     objects are properly configured.  This avoids crashes in 3rd party
     packages that don’t use regular API to create new types.

   - gh-96005(23): On WASI *note ENOTCAPABLE: 18e3. is now mapped to
     *note PermissionError: d6b.  The *note errno: 57. modules exposes
     the new error number.  ‘getpath.py’ now ignores ‘PermissionError’
     when it cannot open landmark files ‘pybuilddir.txt’ and
     ‘pyenv.cfg’.

   - gh-93678(24): Added test a harness for direct unit tests of the
     compiler’s optimization stage.  The
     ‘_testinternalcapi.optimize_cfg()’ function runs the optimiser on a
     sequence of instructions.  The ‘CfgOptimizationTestCase’ class in
     ‘test.support’ has utilities for invoking the optimizer and
     checking the output.

   - gh-95245(25): Reduces the size of a “simple” Python object from 8
     to 6 words by moving the weakreflist pointer into the pre-header
     directly before the object’s dict/values pointer.

   - gh-90997(26): Compile virtual *note try: 6ec./*note except: 18b.
     blocks to handle exceptions raised during *note close(): 15df. or
     *note throw(): 4fb. calls through a suspended frame.

   - gh-95977(27): Optimized calling *note __get__(): 1537. with
     vectorcall.  Patch by Kumar Aditya.

   - gh-91210(28): Improve error message when a parameter without a
     default value follows one with a default value, and show the same
     message, even when the non-default/default sequence is preceded by
     positional-only parameters.

   - gh-95922(29): Fixed bug where the compiler’s
     ‘eliminate_empty_basic_blocks’ function ignores the last block of
     the code unit.

   - gh-95818(30): Skip over incomplete frames in *note
     PyThreadState_GetFrame(): 791.

   - gh-95876(31): Fix format string in
     ‘_PyPegen_raise_error_known_location’ that can lead to memory
     corruption on some 64bit systems.  The function was building a
     tuple with ‘i’ (int) instead of ‘n’ (Py_ssize_t) for Py_ssize_t
     arguments.

   - gh-95605(32): Fix misleading contents of error message when
     converting an all-whitespace string to *note float: 2f7.

   - gh-95150(33): Update code object hashing and equality to consider
     all debugging and exception handling tables.  This fixes an issue
     where certain non-identical code objects could be “deduplicated”
     during compilation.

   - gh-91146(34): Reduce allocation size of *note list: 614. from *note
     str.split(): ede. and *note str.rsplit(): 129c.  Patch by Donghee
     Na and Inada Naoki.

   - gh-87092(35): Create a ‘jump target label’ abstraction in the
     compiler so that the compiler’s codegen stage does not work
     directly with basic blocks.  This prepares the code for changes to
     the underlying CFG generation mechanism.

   - gh-95355(36): ‘_PyPegen_Parser_New’ now properly detects token
     memory allocation errors.  Patch by Honglin Zhu.

   - gh-90081(37): Run Python code in tracer/profiler function at full
     speed.  Fixes slowdown in earlier versions of 3.11.

   - gh-95324(38): Emit a warning in debug mode if an object does not
     call *note PyObject_GC_UnTrack(): 1555. before deallocation.  Patch
     by Pablo Galindo.

   - gh-95245(39): Merge managed dict and values pointer into a single
     tagged pointer to save one word in the pre-header.

   - gh-93678(40): Add cfg_builder struct and refactor the relevant code
     so that a cfg can be constructed without an instance of the
     compiler struct.

   - gh-95185(41): Prevented crashes in the AST constructor when
     compiling some absurdly long expressions like ‘"+0"*1000000’.
     *note RecursionError: d96. is now raised instead.  Patch by Pablo
     Galindo

   - gh-93351(42): *note ast.AST: 1a6. node positions are now validated
     when provided to *note compile(): 192. and other related functions.
     If invalid positions are detected, a *note ValueError: 202. will be
     raised.

   - gh-94438(43): Fix an issue that caused extended opcode arguments
     and some conditional pops to be ignored when calculating valid jump
     targets for assignments to the ‘f_lineno’ attribute of frame
     objects.  In some cases, this could cause inconsistent internal
     state, resulting in a hard crash of the interpreter.

   - gh-95060(44): Undocumented ‘PyCode_Addr2Location’ function now
     properly returns when ‘addrq’ argument is less than zero.

   - gh-95113(45): Replace all ‘EXTENDED_ARG_QUICK’ instructions with
     basic *note EXTENDED_ARG: 18c1. instructions in unquickened code.
     Consumers of non-adaptive bytecode should be able to handle
     extended arguments the same way they were handled in CPython 3.10
     and older.

   - gh-91409(46): Fix incorrect source location info caused by certain
     optimizations in the bytecode compiler.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96636

   (2) https://github.com/python/cpython/issues/96572

   (3) https://github.com/python/cpython/issues/96611

   (4) https://github.com/python/cpython/issues/96612

   (5) https://github.com/python/cpython/issues/90230

   (6) https://github.com/python/cpython/issues/96587

   (7) https://peps.python.org/pep-0654/

   (8) https://github.com/python/cpython/issues/96569

   (9) https://github.com/python/cpython/issues/96582

   (10) https://github.com/python/cpython/issues/91079

   (11) https://github.com/python/cpython/issues/93911

   (12) https://github.com/python/cpython/issues/96348

   (13) https://github.com/python/cpython/issues/95196

   (14) https://github.com/python/cpython/issues/96364

   (15) https://github.com/python/cpython/issues/96352

   (16) https://github.com/python/cpython/issues/93554

   (17) https://github.com/python/cpython/issues/96268

   (18) https://github.com/python/cpython/issues/96237

   (19) https://github.com/python/cpython/issues/96187

   (20) https://github.com/python/cpython/issues/96143

   (21) https://github.com/python/cpython/issues/96071

   (22) https://github.com/python/cpython/issues/96046

   (23) https://github.com/python/cpython/issues/96005

   (24) https://github.com/python/cpython/issues/93678

   (25) https://github.com/python/cpython/issues/95245

   (26) https://github.com/python/cpython/issues/90997

   (27) https://github.com/python/cpython/issues/95977

   (28) https://github.com/python/cpython/issues/91210

   (29) https://github.com/python/cpython/issues/95922

   (30) https://github.com/python/cpython/issues/95818

   (31) https://github.com/python/cpython/issues/95876

   (32) https://github.com/python/cpython/issues/95605

   (33) https://github.com/python/cpython/issues/95150

   (34) https://github.com/python/cpython/issues/91146

   (35) https://github.com/python/cpython/issues/87092

   (36) https://github.com/python/cpython/issues/95355

   (37) https://github.com/python/cpython/issues/90081

   (38) https://github.com/python/cpython/issues/95324

   (39) https://github.com/python/cpython/issues/95245

   (40) https://github.com/python/cpython/issues/93678

   (41) https://github.com/python/cpython/issues/95185

   (42) https://github.com/python/cpython/issues/93351

   (43) https://github.com/python/cpython/issues/94438

   (44) https://github.com/python/cpython/issues/95060

   (45) https://github.com/python/cpython/issues/95113

   (46) https://github.com/python/cpython/issues/91409


File: python.info,  Node: Library<57>,  Next: Core and Builtins<55>,  Prev: Core and Builtins<54>,  Up: Python 3 12 0 alpha 1

1.23.35.9 Library
.................

   - gh-95023(1): Implement *note os.setns(): 18e5. and *note
     os.unshare(): 18e6. for Linux.  Patch by Noam Cohen.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95023


File: python.info,  Node: Core and Builtins<55>,  Next: Library<58>,  Prev: Library<57>,  Up: Python 3 12 0 alpha 1

1.23.35.10 Core and Builtins
............................

   - gh-94036(1): Fix incorrect source location info for some multi-line
     attribute accesses and method calls.

   - gh-94938(2): Fix error detection in some builtin functions when
     keyword argument name is an instance of a str subclass with
     overloaded ‘__eq__’ and ‘__hash__’.  Previously it could cause
     SystemError or other undesired behavior.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94036

   (2) https://github.com/python/cpython/issues/94938


File: python.info,  Node: Library<58>,  Next: Core and Builtins<56>,  Prev: Core and Builtins<55>,  Up: Python 3 12 0 alpha 1

1.23.35.11 Library
..................

   - gh-94996(1): *note ast.parse(): 1a8. will no longer parse function
     definitions with positional-only params when passed
     ‘feature_version’ less than ‘(3, 8)’.  Patch by Shantanu Jain.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94996


File: python.info,  Node: Core and Builtins<56>,  Next: Library<59>,  Prev: Library<58>,  Up: Python 3 12 0 alpha 1

1.23.35.12 Core and Builtins
............................

   - gh-94739(1): Allow jumping within, out of, and across exception
     handlers in the debugger.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94739


File: python.info,  Node: Library<59>,  Next: Core and Builtins<57>,  Prev: Core and Builtins<56>,  Up: Python 3 12 0 alpha 1

1.23.35.13 Library
..................

   - gh-94949(1): *note ast.parse(): 1a8. will no longer parse
     parenthesized context managers when passed ‘feature_version’ less
     than ‘(3, 9)’.  Patch by Shantanu Jain.

   - gh-94947(2): *note ast.parse(): 1a8. will no longer parse
     assignment expressions when passed ‘feature_version’ less than ‘(3,
     8)’.  Patch by Shantanu Jain.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/94949

   (2) https://github.com/python/cpython/issues/94947


File: python.info,  Node: Core and Builtins<57>,  Next: Library<60>,  Prev: Library<59>,  Up: Python 3 12 0 alpha 1

1.23.35.14 Core and Builtins
............................

   - gh-91256(1): Ensures the program name is known for help text during
     interpreter startup.

   - gh-94869(2): Fix the column offsets for some expressions in
     multi-line f-strings *note ast: 8. nodes.  Patch by Pablo Galindo.

   - gh-94893(3): Fix an issue where frame object manipulations could
     corrupt inline bytecode caches.

   - gh-94822(4): Fix an issue where lookups of metaclass descriptors
     may be ignored when an identically-named attribute also exists on
     the class itself.

   - gh-91153(5): Fix an issue where a *note bytearray: 2ea. item
     assignment could crash if it’s resized by the new value’s
     ‘__index__()’ method.

   - gh-90699(6): Fix reference counting bug in ‘bool.__repr__()’.
     Patch by Kumar Aditya.

   - gh-94694(7): Fix an issue that could cause code with multi-line
     method lookups to have misleading or incorrect column offset
     information.  In some cases (when compiling a hand-built AST) this
     could have resulted in a hard crash of the interpreter.

   - gh-93252(8): Fix an issue that caused internal frames to outlive
     failed Python function calls, possibly resulting in memory leaks or
     hard interpreter crashes.

   - gh-94215(9): Fix an issue where exceptions raised by line-tracing
     events would cause frames to be left in an invalid state, possibly
     resulting in a hard crash of the interpreter.

   - gh-92228(10): Disable the compiler’s inline-small-exit-blocks
     optimization for exit blocks that are associated with source code
     lines.  This fixes a bug where the debugger cannot tell where an
     exception handler ends and the following code block begins.

   - gh-94485(11): Line number of a module’s ‘RESUME’ instruction is set
     to 0 as specified in PEP 626(12).

   - gh-94438(13): Account for instructions that can push NULL to the
     stack when setting line number in a frame.  Prevents some
     (unlikely) crashes.

   - gh-91719(14): Reload ‘opcode’ when raising ‘unknown opcode error’
     in the interpreter main loop, for C compilers to generate
     dispatching code independently.

   - gh-94329(15): Compile and run code with unpacking of extremely
     large sequences (1000s of elements).  Such code failed to compile.
     It now compiles and runs correctly.

   - gh-94360(16): Fixed a tokenizer crash when reading encoded files
     with syntax errors from ‘stdin’ with non utf-8 encoded text.  Patch
     by Pablo Galindo

   - gh-88116(17): Fix an issue when reading line numbers from code
     objects if the encoded line numbers are close to ‘INT_MIN’.  Patch
     by Pablo Galindo

   - gh-94262(18): Don’t create frame objects for incomplete frames.
     Prevents the creation of generators and closures from being
     observable to Python and C extensions, restoring the behavior of
     3.10 and earlier.

   - gh-94192(19): Fix error for dictionary literals with invalid
     expression as value.

   - gh-87995(20): *note types.MappingProxyType: 470. instances are now
     hashable if the underlying mapping is hashable.

   - gh-93883(21): Revise the display strategy of traceback enhanced
     error locations.  The indicators are only shown when the location
     doesn’t span the whole line.

   - gh-94163(22): Add *note BINARY_SLICE: 4e2. and *note STORE_SLICE:
     4e3. instructions for more efficient handling and better
     specialization of slicing operations, where the slice is explicit
     in the source code.

   - gh-94021(23): Fix unreachable code warning in
     ‘Python/specialize.c’.

   - gh-93911(24): Specialize ‘LOAD_ATTR’ for objects with custom
     ‘__getattribute__’.

   - gh-93955(25): Improve performance of attribute lookups on objects
     with custom ‘__getattribute__’ and ‘__getattr__’.  Patch by Ken
     Jin.

   - gh-93911(26): Specialize ‘LOAD_ATTR’ for ‘property()’ attributes.

   - gh-93678(27): Refactor compiler optimisation code so that it no
     longer needs the ‘struct assembler’ and ‘struct compiler’ passed
     around.  Instead, each function takes the CFG and other data that
     it actually needs.  This will make it possible to test this code
     directly.

   - gh-93841(28): When built with ‘-enable-pystats’, ‘sys._stats_on()’,
     ‘sys._stats_off()’, ‘sys._stats_clear()’ and ‘sys._stats_dump()’
     functions have been added to enable gathering stats for parts of
     programs.

   - gh-93516(29): Store offset of first traceable instruction in code
     object to avoid having to recompute it for each instruction when
     tracing.

   - gh-93516(30): Lazily create a table mapping bytecode offsets to
     line numbers to speed up calculation of line numbers when tracing.

   - gh-89828(31): *note types.GenericAlias: 7f0. no longer relays the
     ‘__class__’ attribute.  For example, ‘isinstance(list[int], type)’
     no longer returns ‘True’.

   - gh-93678(32): Refactor the compiler to reduce boilerplate and
     repetition.

   - gh-93671(33): Fix some exponential backtrace case happening with
     deeply nested sequence patterns in match statements.  Patch by
     Pablo Galindo

   - gh-93662(34): Make sure that the end column offsets are correct in
     multi-line method calls.  Previously, the end column could precede
     the column offset.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91256

   (2) https://github.com/python/cpython/issues/94869

   (3) https://github.com/python/cpython/issues/94893

   (4) https://github.com/python/cpython/issues/94822

   (5) https://github.com/python/cpython/issues/91153

   (6) https://github.com/python/cpython/issues/90699

   (7) https://github.com/python/cpython/issues/94694

   (8) https://github.com/python/cpython/issues/93252

   (9) https://github.com/python/cpython/issues/94215

   (10) https://github.com/python/cpython/issues/92228

   (11) https://github.com/python/cpython/issues/94485

   (12) https://peps.python.org/pep-0626/

   (13) https://github.com/python/cpython/issues/94438

   (14) https://github.com/python/cpython/issues/91719

   (15) https://github.com/python/cpython/issues/94329

   (16) https://github.com/python/cpython/issues/94360

   (17) https://github.com/python/cpython/issues/88116

   (18) https://github.com/python/cpython/issues/94262

   (19) https://github.com/python/cpython/issues/94192

   (20) https://github.com/python/cpython/issues/87995

   (21) https://github.com/python/cpython/issues/93883

   (22) https://github.com/python/cpython/issues/94163

   (23) https://github.com/python/cpython/issues/94021

   (24) https://github.com/python/cpython/issues/93911

   (25) https://github.com/python/cpython/issues/93955

   (26) https://github.com/python/cpython/issues/93911

   (27) https://github.com/python/cpython/issues/93678

   (28) https://github.com/python/cpython/issues/93841

   (29) https://github.com/python/cpython/issues/93516

   (30) https://github.com/python/cpython/issues/93516

   (31) https://github.com/python/cpython/issues/89828

   (32) https://github.com/python/cpython/issues/93678

   (33) https://github.com/python/cpython/issues/93671

   (34) https://github.com/python/cpython/issues/93662


File: python.info,  Node: Library<60>,  Next: Core and Builtins<58>,  Prev: Core and Builtins<57>,  Up: Python 3 12 0 alpha 1

1.23.35.15 Library
..................

   - gh-93461(1): *note importlib.invalidate_caches(): c30. now drops
     entries from *note sys.path_importer_cache: 5e7. with a relative
     path as name.  This solves a caching issue when a process changes
     its current working directory.

     ‘FileFinder’ no longer inserts a dot in the path, e.g.
     ‘/egg/./spam’ is now ‘/egg/spam’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93461


File: python.info,  Node: Core and Builtins<58>,  Next: Library<61>,  Prev: Library<60>,  Up: Python 3 12 0 alpha 1

1.23.35.16 Core and Builtins
............................

   - gh-93621(1): Change order of bytecode instructions emitted for
     *note with: 5d5. and *note async with: 5d8. to reduce the number of
     entries in the exception table.

   - gh-93533(2): Reduce the size of the inline cache for ‘LOAD_METHOD’
     by 2 bytes.

   - gh-93444(3): Removed redundant fields from the compiler’s
     basicblock struct: ‘b_nofallthrough’, ‘b_exit’, ‘b_return’.  They
     can be easily calculated from the opcode of the last instruction of
     the block.

   - gh-93429(4): ‘LOAD_METHOD’ instruction has been removed.  It was
     merged back into ‘LOAD_ATTR’.

   - gh-93418(5): Fixed an assert where an f-string has an equal sign
     ‘=’ following an expression, but there’s no trailing brace.  For
     example, f”{i=”.

   - gh-93382(6): Cache the result of *note PyCode_GetCode(): 77b.
     function to restore the 'O'(1) lookup of the ‘co_code’ attribute.

   - gh-93359(7): Ensure that custom *note ast: 8. nodes without
     explicit end positions can be compiled.  Patch by Pablo Galindo.

   - gh-93356(8): Code for exception handlers is emitted at the end of
     the code unit’s bytecode.  This avoids one jump when no exception
     is raised.

   - gh-93354(9): Use exponential backoff for specialization counters in
     the interpreter.  Can reduce the number of failed specializations
     significantly and avoid slowdown for those parts of a program that
     are not suitable for specialization.

   - gh-93283(10): Improve error message for invalid syntax of
     conversion character in f-string expressions.

   - gh-93345(11): Fix a crash in substitution of a ‘TypeVar’ in nested
     generic alias after ‘TypeVarTuple’.

   - gh-93223(12): When a bytecode instruction jumps to an unconditional
     jump instruction, the first instruction can often be optimized to
     target the unconditional jump’s target directly.  For tracing
     reasons, this would previously only occur if both instructions have
     the same line number.  This also now occurs if the unconditional
     jump is artificial, i.e., if it has no associated line number.

   - gh-84694(13): The ‘--experimental-isolated-subinterpreters’
     configure option and ‘EXPERIMENTAL_ISOLATED_SUBINTERPRETERS’ macro
     have been removed.

   - gh-91924(14): Fix ‘__lltrace__’ debug feature if the stdout
     encoding is not UTF-8.  Patch by Victor Stinner.

   - gh-93040(15): Wraps unused parameters in ‘Objects/obmalloc.c’ with
     ‘Py_UNUSED’.

   - gh-93143(16): Avoid ‘NULL’ checks for uninitialized local variables
     by determining at compile time which variables must be initialized.

   - gh-93061(17): Backward jumps after ‘async for’ loops are no longer
     given dubious line numbers.

   - gh-93065(18): Fix contextvars HAMT implementation to handle
     iteration over deep trees.

     The bug was discovered and fixed by Eli Libman.  See
     MagicStack/immutables#84(19) for more details.

   - gh-93012(20): Added the new function *note PyType_FromMetaclass():
     553, which generalizes the existing *note
     PyType_FromModuleAndSpec(): 554. using an additional metaclass
     argument.  This is useful for language binding tools, where it can
     be used to intercept type-related operations like subclassing or
     static attribute access by specifying a metaclass with custom
     slots.

     Importantly, *note PyType_FromMetaclass(): 553. is available in the
     Limited API, which provides a path towards migrating more binding
     tools onto the Stable ABI.

   - gh-93021(21): Fix the ‘__text_signature__’ for ‘__get__()’ methods
     implemented in C. Patch by Jelle Zijlstra.

   - gh-89914(22): The operand of the ‘YIELD_VALUE’ instruction is set
     to the stack depth.  This is done to help frame handling on ‘yield’
     and may assist debuggers.

   - gh-92955(23): Fix memory leak in code object’s lines and positions
     iterators as they were not finalized at exit.  Patch by Kumar
     Aditya.

   - gh-92930(24): Fixed a crash in ‘_pickle.c’ from mutating
     collections during ‘__reduce__’ or ‘persistent_id’.

   - gh-90690(25): The PRECALL instruction has been removed.  It offered
     only a small advantage for specialization and is not needed in the
     vast majority of cases.

   - gh-92914(26): Always round the allocated size for lists up to the
     nearest even number.

   - gh-92858(27): Improve error message for some suites with syntax
     error before ‘:’

   - gh-90473(28): Decrease default recursion limit on WASI to address
     limited call stack size.

   - gh-92804(29): Fix memory leak in ‘memoryview’ iterator as it was
     not finalized at exit.  Patch by Kumar Aditya.

   - gh-92777(30): Specialize ‘LOAD_METHOD’ for objects with lazy
     dictionaries.  Patch by Ken Jin.

   - gh-92658(31): Add support for connecting and binding to Hyper-V
     sockets on Windows Hyper-V hosts and guests.

   - gh-92236(32): Remove spurious “LINE” event when starting a
     generator or coroutine, visible tracing functions implemented in C.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/93621

   (2) https://github.com/python/cpython/issues/93533

   (3) https://github.com/python/cpython/issues/93444

   (4) https://github.com/python/cpython/issues/93429

   (5) https://github.com/python/cpython/issues/93418

   (6) https://github.com/python/cpython/issues/93382

   (7) https://github.com/python/cpython/issues/93359

   (8) https://github.com/python/cpython/issues/93356

   (9) https://github.com/python/cpython/issues/93354

   (10) https://github.com/python/cpython/issues/93283

   (11) https://github.com/python/cpython/issues/93345

   (12) https://github.com/python/cpython/issues/93223

   (13) https://github.com/python/cpython/issues/84694

   (14) https://github.com/python/cpython/issues/91924

   (15) https://github.com/python/cpython/issues/93040

   (16) https://github.com/python/cpython/issues/93143

   (17) https://github.com/python/cpython/issues/93061

   (18) https://github.com/python/cpython/issues/93065

   (19) https://github.com/MagicStack/immutables/issues/84

   (20) https://github.com/python/cpython/issues/93012

   (21) https://github.com/python/cpython/issues/93021

   (22) https://github.com/python/cpython/issues/89914

   (23) https://github.com/python/cpython/issues/92955

   (24) https://github.com/python/cpython/issues/92930

   (25) https://github.com/python/cpython/issues/90690

   (26) https://github.com/python/cpython/issues/92914

   (27) https://github.com/python/cpython/issues/92858

   (28) https://github.com/python/cpython/issues/90473

   (29) https://github.com/python/cpython/issues/92804

   (30) https://github.com/python/cpython/issues/92777

   (31) https://github.com/python/cpython/issues/92658

   (32) https://github.com/python/cpython/issues/92236


File: python.info,  Node: Library<61>,  Next: Core and Builtins<59>,  Prev: Core and Builtins<58>,  Up: Python 3 12 0 alpha 1

1.23.35.17 Library
..................

   - gh-91102(1): ‘_warnings.warn_explicit()’ is ported to Argument
     Clinic.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91102


File: python.info,  Node: Core and Builtins<59>,  Next: Library<62>,  Prev: Library<61>,  Up: Python 3 12 0 alpha 1

1.23.35.18 Core and Builtins
............................

   - gh-92619(1): Make the compiler duplicate an exit block only if none
     of its instructions have a lineno (previously only the first
     instruction in the block was checked, leading to unnecessarily
     duplicated blocks).

   - gh-88750(2): The deprecated debug build only ‘PYTHONTHREADDEBUG’
     environment variable no longer does anything.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92619

   (2) https://github.com/python/cpython/issues/88750


File: python.info,  Node: Library<62>,  Next: Core and Builtins<60>,  Prev: Core and Builtins<59>,  Up: Python 3 12 0 alpha 1

1.23.35.19 Library
..................

   - gh-92261(1): Fix hang when trying to iterate over a ‘typing.Union’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92261


File: python.info,  Node: Core and Builtins<60>,  Next: Library<63>,  Prev: Library<62>,  Up: Python 3 12 0 alpha 1

1.23.35.20 Core and Builtins
............................

   - gh-91432(1): Specialized the *note FOR_ITER: 1866. opcode using the
     PEP 659 machinery

   - gh-91399(2): Removed duplicate ‘{0, 0, 0, 0, 0, 0}’ entry in
     ‘Objects/unicodetype_db.h’.

   - gh-91578(3): Updates the error message for abstract class.

   - bpo-47091(4): Improve performance of repetition of *note list: 614.
     and *note tuple: 373. by using ‘memcpy’ to copy data and performing
     the reference increments in one step.

   - bpo-46142(5): Make ‘--help’ output shorter by moving some info to
     the new ‘--help-env’ and ‘--help-xoptions’ command-line options.
     Also add ‘--help-all’ option to print complete usage.

   - bpo-42316(6): Document some places where an assignment expression
     needs parentheses.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91432

   (2) https://github.com/python/cpython/issues/91399

   (3) https://github.com/python/cpython/issues/91578

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47091

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46142

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42316


File: python.info,  Node: Library<63>,  Next: Documentation<26>,  Prev: Core and Builtins<60>,  Up: Python 3 12 0 alpha 1

1.23.35.21 Library
..................

   - gh-89237(1): Fix hang on Windows in ‘subprocess.wait_closed()’ in
     *note asyncio: a. with *note ProactorEventLoop: 60c.  Patch by
     Kumar Aditya.

   - gh-97928(2): ‘tkinter.Text.count()’ raises now an exception for
     options starting with “-” instead of silently ignoring them.

   - gh-98393(3): The *note os: a1. module no longer accepts bytes-like
     paths, like *note bytearray: 2ea. and *note memoryview: 2eb. types:
     only the exact *note bytes: 1c2. type is accepted for bytes
     strings.  Patch by Victor Stinner.

   - gh-98363(4): Added itertools.batched() to batch data into lists of
     a given length with the last list possibly being shorter than the
     others.

   - gh-98331(5): Update the bundled copies of pip and setuptools to
     versions 22.3 and 65.5.0 respectively.

   - gh-98307(6): A *note createSocket(): 65e. method was added to *note
     SysLogHandler: 65f.

   - gh-96035(7): Fix bug in *note urllib.parse.urlparse(): 30d. that
     causes certain port numbers containing whitespace, underscores,
     plus and minus signs, or non-ASCII digits to be incorrectly
     accepted.

   - gh-98257(8): Make *note sys.setprofile(): 154d. and *note
     sys.settrace(): 154e. functions reentrant.  They can no long fail
     with: ‘RuntimeError("Cannot install a trace function while another
     trace function is being installed")’.  Patch by Victor Stinner.

   - gh-98251(9): Allow *note venv: 111. to pass along ‘PYTHON*’
     variables to ‘ensurepip’ and ‘pip’ when they do not impact path
     resolution

   - gh-94597(10): Deprecated *note
     asyncio.AbstractEventLoopPolicy.get_child_watcher(): 2c1. and *note
     asyncio.AbstractEventLoopPolicy.set_child_watcher(): 2c0. methods
     to be removed in Python 3.14.  Patch by Kumar Aditya.

   - gh-98178(11): On macOS, fix a crash in *note syslog.syslog(): 543.
     in multi-threaded applications.  On macOS, the libc ‘syslog()’
     function is not thread-safe, so ‘syslog.syslog()’ no longer
     releases the GIL to call it.  Patch by Victor Stinner.

   - gh-44098(12): Release the GIL when creating *note mmap.mmap: 20b.
     objects on Unix.

   - gh-87730(13): Wrap network errors consistently in urllib FTP
     support, so the test suite doesn’t fail when a network is available
     but the public internet is not reachable.

   - gh-94597(14): The child watcher classes *note
     MultiLoopChildWatcher: 2ba, *note FastChildWatcher: 2bb. and *note
     SafeChildWatcher: 2bd. are deprecated and will be removed in Python
     3.14.  Patch by Kumar Aditya.

   - gh-98023(15): Change default child watcher to *note
     PidfdChildWatcher: 47c. on Linux systems which supports it.  Patch
     by Kumar Aditya.

   - gh-90985(16): Earlier in 3.11 we deprecated
     ‘asyncio.Task.cancel("message")’.  We realized we were too harsh,
     and have undeprecated it.

   - gh-65961(17): Do not rely solely on ‘__cached__’ on modules; code
     will also support ‘__spec__.cached’.

   - gh-97646(18): Replace deprecated ‘application/javascript’ with
     ‘text/javascript’ in *note mimetypes: 8f.  See RFC 9239(19).  Patch
     by Noam Cohen.

   - gh-97930(20): Apply changes from importlib_resources 5.8 and 5.9:
     ‘Traversable.joinpath’ provides a concrete implementation.
     ‘as_file’ now supports directories of resources.

   - gh-97850(21): Remove deprecated ‘importlib.util.set_loader()’ and
     ‘importlib.util.module_for_loader()’ from *note importlib.util: 7d.

   - gh-97837(22): Change deprecate warning message in *note unittest:
     106. from

     ‘It is deprecated to return a value!=None’

     to

     ‘It is deprecated to return a value that is not None from a test
     case’

   - gh-97825(23): Fixes *note AttributeError: 34e. when *note
     subprocess.check_output(): ffb. is used with argument ‘input=None’
     and either of the arguments 'encoding' or 'errors' are used.

   - gh-97008(24): *note NameError: 442. and *note AttributeError: 34e.
     spelling suggestions provided since gh-82711(25) are now also
     emitted by the pure Python *note traceback: fe. module.  Tests for
     those suggestions now exercise both implementations to ensure they
     are equivalent.  Patch by Carl Friedrich Bolz-Tereick and Łukasz
     Langa.

   - gh-97799(26): ‘dataclass’ now uses *note inspect.get_annotations():
     819. to examine the annotations on class objects.

   - gh-97781(27): Removed deprecated interfaces in ‘importlib.metadata’
     (entry points accessed as dictionary, implicit dictionary
     construction of sequence of ‘EntryPoint’ objects, mutablility of
     ‘EntryPoints’ result, access of entry point by index).
     ‘entry_points’ now has a simpler, more straightforward API
     (returning ‘EntryPoints’).

   - gh-96827(28): Avoid spurious tracebacks from *note asyncio: a. when
     default executor cleanup is delayed until after the event loop is
     closed (e.g.  as the result of a keyboard interrupt).

   - gh-95534(29): ‘gzip.GzipFile.read()’ reads 10% faster.

   - gh-97592(30): Avoid a crash in the C version of *note
     asyncio.Future.remove_done_callback(): 16a9. when an evil argument
     is passed.

   - gh-97639(31): Remove ‘tokenize.NL’ check from *note tabnanny: dd.

   - gh-97545(32): Make Semaphore run faster.

   - gh-73588(33): Fix generation of the default name of
     ‘tkinter.Checkbutton’.  Previously, checkbuttons in different
     parent widgets could have the same short name and share the same
     state if arguments “name” and “variable” are not specified.  Now
     they are globally unique.

   - gh-96865(34): fix Flag to use boundary CONFORM

     This restores previous Flag behavior of allowing flags with
     non-sequential values to be combined; e.g.

     class Skip(Flag): TWO = 2 EIGHT = 8

     Skip.TWO | Skip.EIGHT -> <Skip.TWO|EIGHT: 10>

   - gh-97005(35): Update bundled libexpat to 2.4.9

   - gh-85760(36): Fix race condition in *note asyncio: a. where *note
     process_exited(): 18f3. called before the *note
     pipe_data_received(): 18f4. leading to inconsistent output.  Patch
     by Kumar Aditya.

   - gh-96704(37): Pass the correct ‘contextvars.Context’ when a
     ‘asyncio’ exception handler is called on behalf of a task or
     callback handle.  This adds a new ‘Task’ method, ‘get_context’, and
     also a new ‘Handle’ method with the same name.  If this method is
     not found on a task object (perhaps because it is a third-party
     library that does not yet provide this method), the context
     prevailing at the time the exception handler is called is used.

   - gh-96819(38): Fixed check in ‘multiprocessing.resource_tracker’
     that guarantees that the length of a write to a pipe is not greater
     than ‘PIPE_BUF’.

   - gh-95865(39): Reduce *note urllib.parse.quote_from_bytes(): 18f5.
     memory use on large values.

     Contributed by Dennis Sweeney.

   - gh-96741(40): Corrected type annotation for dataclass attribute
     ‘pstats.FunctionProfile.ncalls’ to be ‘str’.

   - gh-96734(41): Update *note unicodedata: 105. database to Unicode
     15.0.0.

   - gh-96735(42): Fix undefined behaviour in *note struct.unpack():
     18f6.

   - gh-46412(43): Improve performance of ‘bool(db)’ for large ndb/gdb
     databases.  Previously this would call ‘len(db)’ which would
     iterate over all keys – the answer (empty or not) is known after
     the first key.

   - gh-96652(44): Fix the faulthandler implementation of
     ‘faulthandler.register(signal, chain=True)’ if the ‘sigaction()’
     function is not available: don’t call the previous signal handler
     if it’s NULL. Patch by Victor Stinner.

   - gh-68163(45): Correct conversion of *note numbers.Rational: 1306.’s
     to *note float: 2f7.

   - gh-96538(46): Speed up ‘bisect.bisect()’ functions by taking
     advantage of type-stability.

   - gh-96465(47): Fraction hashes are now cached.

   - gh-96079(48): In *note typing: 104, fix missing field ‘name’ and
     incorrect ‘__module__’ in _AnnotatedAlias.

   - gh-96415(49): Remove ‘types._cell_factory’ from module namespace.

   - gh-95987(50): Fix ‘repr’ of ‘Any’ subclasses.

   - gh-96388(51): Work around missing socket functions in *note socket:
     dcf.’s ‘__repr__’.

   - gh-96385(52): Fix ‘TypeVarTuple.__typing_prepare_subst__’.
     ‘TypeError’ was not raised when using more than one ‘TypeVarTuple’,
     like ‘[*T, *V]’ in type alias substitutions.

   - gh-96142(53): Add ‘match_args’, ‘kw_only’, ‘slots’, and
     ‘weakref_slot’ to ‘_DataclassParams’.

   - gh-96073(54): In *note inspect: 7e, fix overeager replacement of
     “‘typing.’” in formatting annotations.

   - gh-89258(55): Added a *note getChildren(): 18f7. method to *note
     logging.Logger: b6a, to get the immediate child loggers of a
     logger.

   - gh-96346(56): Use double caching for compiled RE patterns.

   - gh-96349(57): Fixed a minor performance regression in
     ‘threading.Event.__init__()’

   - gh-90467(58): Fix ‘asyncio.streams.StreamReaderProtocol’ to keep a
     strong reference to the created task, so that it’s not garbage
     collected

   - gh-96172(59): Fix a bug in ‘unicodedata’: ‘east_asian_width’ used
     to return the wrong value for unassigned characters; and for yet
     unassigned, but reserved characters.

   - gh-96159(60): Fix a performance regression in logging
     TimedRotatingFileHandler.  Only check for special files when the
     rollover time has passed.

   - gh-96175(61): Fix unused ‘localName’ parameter in the ‘Attr’ class
     in *note xml.dom.minidom: 122.

   - gh-96145(62): Add AttrDict to JSON module for use with object_hook.

   - gh-96052(63): Fix handling compiler warnings (SyntaxWarning and
     DeprecationWarning) in *note codeop.compile_command(): 18f8. when
     checking for incomplete input.  Previously it emitted warnings and
     raised a SyntaxError.  Now it always returns ‘None’ for incomplete
     input without emitting any warnings.

   - gh-96125(64): Fix incorrect condition that causes
     ‘sys.thread_info.name’ to be wrong on pthread platforms.

   - gh-96019(65): Fix a bug in the ‘makeunicodedata.py’ script leading
     to about 13 KiB of space saving in the ‘unicodedata’ module,
     specifically the character decomposition data.

   - gh-95463(66): Remove an incompatible change from bpo-28080(67) that
     caused a regression that ignored the utf8 in ‘ZipInfo.flag_bits’.
     Patch by Pablo Galindo.

   - gh-69142(68): Add ‘%:z’ strftime format code (generates tzoffset
     with colons as separator), see *note strftime() and strptime()
     Behavior: 18f9.

   - gh-95899(69): Fix *note asyncio.Runner: 603. to call *note
     asyncio.set_event_loop(): 18fa. only once to avoid calling *note
     attach_loop(): 18fb. multiple times on child watchers.  Patch by
     Kumar Aditya.

   - gh-95736(70): Fix *note unittest.IsolatedAsyncioTestCase: 30c. to
     set event loop before calling setup functions.  Patch by Kumar
     Aditya.

   - gh-95865(71): Speed up *note urllib.parse.quote_from_bytes(): 18f5.
     by replacing a list comprehension with ‘map()’.

   - gh-95861(72): Add support for computing Spearman’s correlation
     coefficient to the existing statistics.correlation() function.

   - gh-95804(73): Fix ‘logging’ shutdown handler so it respects
     ‘MemoryHandler.flushOnClose’.

   - gh-95704(74): When a task catches *note asyncio.CancelledError:
     1b8. and raises some other error, the other error should generally
     not silently be suppressed.

   - gh-95149(75): The *note HTTPStatus: 909. enum offers a couple of
     properties to indicate the HTTP status category e.g.
     ‘HTTPStatus.OK.is_success’.

   - gh-95609(76): Update bundled pip to 22.2.2.

   - gh-95289(77): Fix *note asyncio.TaskGroup: 1b5. to propagate
     exception when *note asyncio.CancelledError: 1b8. was replaced with
     another exception by a context manager.  Patch by Kumar Aditya and
     Guido van Rossum.

   - gh-94909(78): Fix incorrect joining of relative Windows paths with
     drives in *note pathlib.PurePath: 4a9. initializer.

   - gh-95385(79): Faster ‘json.dumps()’ when sorting of keys is not
     requested (default).

   - gh-83901(80): Improve *note Signature.bind: 1667. error message for
     missing keyword-only arguments.

   - gh-95339(81): Update bundled pip to 22.2.1.

   - gh-95045(82): Fix GC crash when deallocating ‘_lsprof.Profiler’ by
     untracking it before calling any callbacks.  Patch by Kumar Aditya.

   - gh-95231(83): Fail gracefully if *note EPERM: 18fc. or *note
     ENOSYS: 18fd. is raised when loading ‘crypt’ methods.  This may
     happen when trying to load ‘MD5’ on a Linux kernel with FIPS
     (Federal Information Processing Standard) enabled.

   - gh-95097(84): Fix *note asyncio.run(): 47f. for *note asyncio.Task:
     1be. implementations without *note uncancel(): 1bb. method.  Patch
     by Kumar Aditya.

   - gh-95087(85): Fix IndexError in parsing invalid date in the *note
     email: 3b. module.

   - gh-95199(86): Upgrade bundled setuptools to 63.2.0.

   - gh-95194(87): Upgrade bundled pip to 22.2.

   - gh-93899(88): Fix check for existence of *note os.EFD_CLOEXEC:
     18fe, *note os.EFD_NONBLOCK: 18ff. and *note os.EFD_SEMAPHORE:
     1900. flags on older kernel versions where these flags are not
     present.  Patch by Kumar Aditya.

   - gh-95166(89): Fix *note concurrent.futures.Executor.map(): e14. to
     cancel the currently waiting on future on an error - e.g.
     TimeoutError or KeyboardInterrupt.

   - gh-95132(90): Fix a *note sqlite3: cf. regression where ‘*args’ and
     ‘**kwds’ were incorrectly relayed from *note connect(): 2a8. to the
     *note Connection: 245. factory.  The regression was introduced in
     3.11a1 with PR 24421 (gh-85128(91)).  Patch by Erlend E. Aasland.

   - gh-93157(92): Fix *note fileinput: 5b. module didn’t support
     ‘errors’ option when ‘inplace’ is true.

   - gh-91212(93): Fixed flickering of the turtle window when the tracer
     is turned off.  Patch by Shin-myoung-serp.

   - gh-95077(94): Add deprecation warning for enum ‘member.member’
     access (e.g.  ‘Color.RED.BLUE’).  Remove ‘EnumMeta.__getattr__’.

   - gh-95109(95): Ensure that timeouts scheduled with *note
     asyncio.Timeout: 17da. that have already expired are delivered
     promptly.

   - gh-95105(96): ‘wsgiref.types.InputStream.__iter__()’ should return
     ‘Iterator[bytes]’, not ‘Iterable[bytes]’.  Patch by Shantanu Jain.

   - gh-95066(97): Replaced assert with exception in *note ast.parse():
     1a8, when ‘feature_version’ has an invalid major version.  Patch by
     Shantanu Jain.

   - gh-77617(98): Add *note sqlite3: cf. *note command-line interface:
     444.  Patch by Erlend Aasland.

   - gh-95005(99): Replace _PyAccu with _PyUnicodeWriter in JSON encoder
     and StringIO and remove the _PyAccu implementation.

   - gh-90085(100): Remove ‘-c/--clock’ and ‘-t/--time’ CLI options of
     *note timeit: ef.  The options had been deprecated since Python 3.3
     and the functionality was removed in Python 3.7.  Patch by Shantanu
     Jain.

   - gh-94857(101): Fix refleak in ‘_io.TextIOWrapper.reconfigure’.
     Patch by Kumar Aditya.

   - gh-94821(102): Fix binding of unix socket to empty address on Linux
     to use an available address from the abstract namespace, instead of
     “0”.

   - gh-94736(103): Fix crash when deallocating an instance of a
     subclass of ‘_multiprocessing.SemLock’.  Patch by Kumar Aditya.

   - gh-81620(104): Add random.binomialvariate().

   - gh-74116(105): Allow *note asyncio.StreamWriter.drain(): 18cc. to
     be awaited concurrently by multiple tasks.  Patch by Kumar Aditya.

   - gh-87822(106): When called with ‘capture_locals=True’, the *note
     traceback: fe. module functions swallow exceptions raised from
     calls to ‘repr()’ on local variables of frames.  This is in order
     to prioritize the original exception over rendering errors.  An
     indication of the failure is printed in place of the missing value.
     (Patch by Simon-Martin Schroeder).

   - gh-88050(107): Fix *note asyncio: a. subprocess transport to kill
     process cleanly when process is blocked and avoid ‘RuntimeError’
     when loop is closed.  Patch by Kumar Aditya.

   - gh-94637(108): ‘SSLContext.set_default_verify_paths()’ now releases
     the GIL around ‘SSL_CTX_set_default_verify_paths’ call.  The
     function call performs I/O and CPU intensive work.

   - gh-94309(109): Deprecate aliases *note typing.Hashable: 4f6. and
     *note typing.Sized: 4f7.

   - gh-92546(110): An undocumented ‘python -m pprint’ benchmark is
     moved into ‘pprint’ suite of pyperformance.  Patch by Oleg Iarygin.

   - gh-94607(111): Fix subclassing complex generics with type variables
     in *note typing: 104.  Previously an error message saying ‘Some
     type variables ... are not listed in Generic[...]’ was shown.
     ‘typing’ no longer populates ‘__parameters__’ with the
     ‘__parameters__’ of a Python class.

   - gh-94619(112): Remove the long-deprecated ‘module_repr()’ from
     *note importlib: 77.

   - gh-93910(113): The ability to access the other values of an enum on
     an enum (e.g.  ‘Color.RED.BLUE’) has been restored in order to fix
     a performance regression.

   - gh-93896(114): Fix *note asyncio.run(): 47f. and *note
     unittest.IsolatedAsyncioTestCase: 30c. to always the set event loop
     as it was done in Python 3.10 and earlier.  Patch by Kumar Aditya.

   - gh-94343(115): Allow setting the attributes of ‘reprlib.Repr’
     during object initialization

   - gh-94382(116): Port static types of ‘_multiprocessing’ module to
     heap types.  Patch by Kumar Aditya.

   - gh-78724(117): Fix crash in *note struct.Struct: 15ad. when it was
     not completely initialized by initializing it in *note __new__():
     583.  Patch by Kumar Aditya.

   - gh-94510(118): Re-entrant calls to *note sys.setprofile(): 154d.
     and *note sys.settrace(): 154e. now raise *note RuntimeError: 195.
     Patch by Pablo Galindo.

   - gh-92336(119): Fix bug where *note linecache.getline(): e56. fails
     on bad files with *note UnicodeDecodeError: a20. or *note
     SyntaxError: 18d.  It now returns an empty string as per the
     documentation.

   - gh-94398(120): Once a *note asyncio.TaskGroup: 1b5. has started
     shutting down (i.e., at least one task has failed and the task
     group has started cancelling the remaining tasks), it should not be
     possible to add new tasks to the task group.

   - gh-94383(121): ‘xml.etree’: Remove the ‘ElementTree.Element.copy()’
     method of the pure Python implementation, deprecated in Python
     3.10, use the *note copy.copy(): 537. function instead.  The C
     implementation of ‘xml.etree’ has no ‘copy()’ method, only a
     ‘__copy__()’ method.  Patch by Victor Stinner.

   - gh-94379(122): *note zipimport: 132.: Remove ‘find_loader()’ and
     ‘find_module()’ methods, deprecated in Python 3.10: use the
     ‘find_spec()’ method instead.  See PEP 451(123) for the rationale.
     Patch by Victor Stinner.

   - gh-94352(124): *note shlex.split(): 53f.: Passing ‘None’ for 's'
     argument now raises an exception, rather than reading *note
     sys.stdin: 540.  The feature was deprecated in Python 3.9.  Patch
     by Victor Stinner.

   - gh-94318(125): Strip trailing spaces in *note pydoc: b5. text
     output.

   - gh-89988(126): Fix memory leak in *note pickle.Pickler: a2b. when
     looking up ‘dispatch_table’.  Patch by Kumar Aditya.

   - gh-90016(127): Deprecate *note sqlite3: cf. *note default adapters
     and converters: 4f2.  Patch by Erlend E. Aasland.

   - gh-94254(128): Fixed types of *note struct: d5. module to be
     immutable.  Patch by Kumar Aditya.

   - gh-93259(129): Now raise ‘ValueError’ when ‘None’ or an empty
     string are passed to ‘Distribution.from_name’ (and other callers).

   - gh-74696(130): *note shutil.make_archive(): 4b6. now passes the
     'root_dir' argument to custom archivers which support it.

   - gh-94216(131): The *note dis: 38. module now has the opcodes for
     pseudo instructions (those which are used by the compiler during
     code generation but then removed or replaced by real opcodes before
     the final bytecode is emitted).

   - gh-93096(132): Removed undocumented ‘python -m codecs’.  Use
     ‘python -m unittest test.test_codecs.EncodedFileTest’ instead.

   - gh-94207(133): Made ‘_struct.Struct’ GC-tracked in order to fix a
     reference leak in the ‘_struct’ module.

   - gh-93096(134): Removed undocumented ‘-t’ argument of ‘python -m
     base64’.  Use ‘python -m unittest
     test.test_base64.LegacyBase64TestCase.test_encodebytes’ instead.

   - gh-94226(135): Remove the ‘locale.format()’ function, deprecated in
     Python 3.7: use *note locale.format_string(): 522. instead.  Patch
     by Victor Stinner.

   - gh-94199(136): Remove the ‘ssl.match_hostname()’ function.  The
     ‘ssl.match_hostname()’ was deprecated in Python 3.7.  OpenSSL
     performs hostname matching since Python 3.7, Python no longer uses
     the ‘ssl.match_hostname()’ function.  Patch by Victor Stinner.

   - gh-94214(137): Document the ‘context’ object used in the
     ‘venv.EnvBuilder’ class, and add the new environment’s library path
     to it.

   - gh-94199(138): Remove the ‘ssl.wrap_socket()’ function, deprecated
     in Python 3.7: instead, create a *note ssl.SSLContext: 294. object
     and call its *note ssl.SSLContext.wrap_socket: 528. method.  Any
     package that still uses ‘ssl.wrap_socket()’ is broken and insecure.
     The function neither sends a SNI TLS extension nor validates server
     hostname.  Code is subject to CWE 295(139) Improper Certificate
     Validation.  Patch by Victor Stinner.

   - gh-94199(140): Remove the ‘ssl.RAND_pseudo_bytes()’ function,
     deprecated in Python 3.6: use *note os.urandom(): 526. or *note
     ssl.RAND_bytes(): 527. instead.  Patch by Victor Stinner.

   - gh-94199(141): *note hashlib: 68.: Remove the pure Python
     implementation of *note hashlib.pbkdf2_hmac(): 512, deprecated in
     Python 3.10.  Python 3.10 and newer requires OpenSSL 1.1.1 ( PEP
     644(142)): this OpenSSL version provides a C implementation of
     ‘pbkdf2_hmac()’ which is faster.  Patch by Victor Stinner.

   - gh-94196(143): *note gzip: 67.: Remove the ‘filename’ attribute of
     *note gzip.GzipFile: 41d, deprecated since Python 2.6, use the
     *note name: 510. attribute instead.  In write mode, the ‘filename’
     attribute added ‘'.gz'’ file extension if it was not present.
     Patch by Victor Stinner.

   - gh-94182(144): run the *note asyncio.PidfdChildWatcher: 47c. on the
     running loop, this allows event loops to run subprocesses when
     there is no default event loop running on the main thread

   - gh-94169(145): Remove ‘io.OpenWrapper’ and ‘_pyio.OpenWrapper’,
     deprecated in Python 3.10: just use *note open(): 51f. instead.
     The ‘open()’ (*note io.open(): 520.) function is a built-in
     function.  Since Python 3.10, ‘_pyio.open()’ is also a static
     method.  Patch by Victor Stinner.

   - gh-91742(146): Fix *note pdb: a5. crash after jump caused by a null
     pointer dereference.  Patch by Kumar Aditya.

   - gh-94101(147): Manual instantiation of *note ssl.SSLSession: d04.
     objects is no longer allowed as it lead to misconfigured instances
     that crashed the interpreter when attributes where accessed on
     them.

   - gh-84753(148): *note inspect.iscoroutinefunction(): 2e4, *note
     inspect.isgeneratorfunction(): 1901, and *note
     inspect.isasyncgenfunction(): 1902. now properly return ‘True’ for
     duck-typed function-like objects like instances of *note
     unittest.mock.AsyncMock: a57.

     This makes *note inspect.iscoroutinefunction(): 2e4. consistent
     with the behavior of ‘asyncio.iscoroutinefunction()’.  Patch by
     Mehdi ABAAKOUK.

   - gh-94028(149): Fix a regression in the *note sqlite3: cf. where
     statement objects were not properly cleared and reset after use in
     cursor iters.  The regression was introduced by PR 27884 in Python
     3.11a1.  Patch by Erlend E. Aasland.

   - gh-93973(150): Add keyword argument ‘all_errors’ to
     ‘asyncio.create_connection’ so that multiple connection errors can
     be raised as an ‘ExceptionGroup’.

   - gh-93963(151): Officially deprecate from ‘importlib.abc’ classes
     moved to ‘importlib.resources.abc’.

   - gh-93858(152): Prevent error when activating venv in nested fish
     instances.

   - gh-93820(153): Pickle *note enum.Flag: 626. by name.

   - gh-93847(154): Fix repr of enum of generic aliases.

   - gh-91404(155): Revert the *note re: b9. memory leak when a match is
     terminated by a signal or memory allocation failure as the
     implemented fix caused a major performance regression.

   - gh-83499(156): Fix double closing of file description in *note
     tempfile: e0.

   - gh-93820(157): Fixed a regression when *note copy.copy(): 537.-ing
     *note enum.Flag: 626. with multiple flag members.

   - gh-79512(158): Fixed names and ‘__module__’ value of *note weakref:
     114. classes *note ReferenceType: 1903, *note ProxyType: 1904,
     *note CallableProxyType: 1905.  It makes them pickleable.

   - gh-91389(159): Fix an issue where *note dis: 38. utilities could
     report missing or incorrect position information in the presence of
     ‘CACHE’ entries.

   - gh-93626(160): Set ‘__future__.annotations’ to have a ‘None’
     mandatoryRelease to indicate that it is currently ‘TBD’.

   - gh-90473(161): Emscripten and WASI have no home directory and
     cannot provide PEP 370(162) user site directory.

   - gh-90494(163): *note copy.copy(): 537. and *note copy.deepcopy():
     b8a. now always raise a TypeError if ‘__reduce__()’ returns a tuple
     with length 6 instead of silently ignore the 6th item or produce
     incorrect result.

   - gh-90549(164): Fix a multiprocessing bug where a global named
     resource (such as a semaphore) could leak when a child process is
     spawned (as opposed to forked).

   - gh-93521(165): Fixed a case where dataclasses would try to add
     ‘__weakref__’ into the ‘__slots__’ for a dataclass that specified
     ‘weakref_slot=True’ when it was already defined in one of its
     bases.  This resulted in a ‘TypeError’ upon the new class being
     created.

   - gh-79579(166): *note sqlite3: cf. now correctly detects DML queries
     with leading comments.  Patch by Erlend E. Aasland.

   - gh-93421(167): Update *note sqlite3.Cursor.rowcount: 1906. when a
     DML statement has run to completion.  This fixes the row count for
     SQL queries like ‘UPDATE ... RETURNING’.  Patch by Erlend E.
     Aasland.

   - gh-93475(168): Expose ‘FICLONE’ and ‘FICLONERANGE’ constants in
     *note fcntl: 59.  Patch by Illia Volochii.

   - gh-93370(169): Deprecate *note sqlite3.version: 2cf. and *note
     sqlite3.version_info: 2d0.

   - gh-91810(170): Suppress writing an XML declaration in open files in
     ‘ElementTree.write()’ with ‘encoding='unicode'’ and
     ‘xml_declaration=None’.

   - gh-91162(171): Support splitting of unpacked arbitrary-length tuple
     over ‘TypeVar’ and ‘TypeVarTuple’ parameters.  For example:

        * ‘A[T, *Ts][*tuple[int, ...]]’ -> ‘A[int, *tuple[int, ...]]’

        * ‘A[*Ts, T][*tuple[int, ...]]’ -> ‘A[*tuple[int, ...], int]’

   - gh-93353(172): Fix the *note importlib.resources.as_file(): 490.
     context manager to remove the temporary file if destroyed late
     during Python finalization: keep a local reference to the *note
     os.remove(): 1134. function.  Patch by Victor Stinner.

   - gh-83658(173): Make ‘multiprocessing.Pool’ raise an exception if
     ‘maxtasksperchild’ is not ‘None’ or a positive int.

   - gh-93312(174): Add *note os.PIDFD_NONBLOCK: 49d. flag to open a
     file descriptor for a process with *note os.pidfd_open(): 47d. in
     non-blocking mode.  Patch by Kumar Aditya.

   - gh-88123(175): Implement ‘Enum.__contains__’ that returns ‘True’ or
     ‘False’ to replace the deprecated behaviour that would sometimes
     raise a *note TypeError: 2c3.

   - gh-93297(176): Make asyncio task groups prevent child tasks from
     being GCed

   - gh-85308(177): Changed *note argparse.ArgumentParser: 53c. to use
     *note filesystem encoding and error handler: 53e. instead of
     default text encoding to read arguments from file (e.g.
     ‘fromfile_prefix_chars’ option).  This change affects Windows;
     argument file should be encoded with UTF-8 instead of ANSI
     Codepage.

   - gh-93156(178): Accessing the *note pathlib.PurePath.parents: 826.
     sequence of an absolute path using negative index values produced
     incorrect results.

   - gh-93162(179): Add the ability for *note
     logging.config.dictConfig(): 11f4. to usefully configure *note
     QueueHandler: 1907. and *note QueueListener: e5f. as a pair, and
     add *note logging.getHandlerByName(): 1908. and *note
     logging.getHandlerNames(): 180d. APIs to allow access to handlers
     by name.

   - gh-93243(180): The ‘smtpd’ module was removed per the schedule in
     PEP 594(181).

   - gh-92886(182): Replace ‘assert’ statements with ‘raise
     AssertionError()’ in ‘BaseHandler’ so that the tested behaviour is
     maintained running with optimizations ‘(-O)’.

   - gh-90155(183): Fix broken *note asyncio.Semaphore: a83. when
     acquire is cancelled.

   - gh-90817(184): The ‘locale.resetlocale()’ function is deprecated
     and will be removed in Python 3.13.  Use
     ‘locale.setlocale(locale.LC_ALL, "")’ instead.  Patch by Victor
     Stinner.

   - gh-91513(185): Added ‘taskName’ attribute to *note logging: 87.
     module for use with *note asyncio: a. tasks.

   - gh-74696(186): *note shutil.make_archive(): 4b6. no longer
     temporarily changes the current working directory during creation
     of standard ‘.zip’ or tar archives.

   - gh-92728(187): The ‘re.template()’ function and the corresponding
     ‘re.TEMPLATE’ and ‘re.T’ flags are restored after they were removed
     in 3.11.0b1, but they are now deprecated, so they might be removed
     from Python 3.13.

   - gh-93033(188): Search in some strings (platform dependent i.e
     [U+0xFFFF, U+0x0100] on Windows or [U+0xFFFFFFFF, U+0x00010000] on
     Linux 64-bit) are now up to 10 times faster.

   - gh-89973(189): Fix ‘re.error’ raised in *note fnmatch: 5c. if the
     pattern contains a character range with upper bound lower than
     lower bound (e.g.  ‘[c-a]’).  Now such ranges are interpreted as
     empty ranges.

   - gh-93044(190): No longer convert the database argument of *note
     sqlite3.connect(): 2a8. to bytes before passing it to the factory.

   - gh-93010(191): In a very special case, the email package tried to
     append the nonexistent ‘InvalidHeaderError’ to the defect list.  It
     should have been ‘InvalidHeaderDefect’.

   - gh-92986(192): Fix *note ast.unparse(): 8ee. when
     ‘ImportFrom.level’ is ‘None’

   - gh-92932(193): Now *note dis(): b4c. and *note get_instructions():
     1d9. handle operand values for instructions prefixed by
     ‘EXTENDED_ARG_QUICK’.  Patch by Sam Gross and Donghee Na.

   - gh-92675(194): Fix ‘venv.ensure_directories()’ to accept *note
     pathlib.Path: 229. arguments in addition to *note str: 44f. paths.
     Patch by David Foster.

   - gh-87901(195): Removed the ‘encoding’ argument from *note
     os.popen(): a96. that was added in 3.11b1.

   - gh-91922(196): Fix function ‘sqlite.connect()’ and the
     ‘sqlite.Connection’ constructor on non-UTF-8 locales.  Also, they
     now support bytes paths non-decodable with the current FS encoding.

   - gh-92869(197): Added *note c_time_t: 1909. to *note ctypes: 2a,
     which has the same size as the ‘time_t’ type in C.

   - gh-92839(198): Fixed crash resulting from calling bisect.insort()
     or bisect.insort_left() with the key argument not equal to ‘None’.

   - gh-90473(199): *note subprocess: d6. now fails early on Emscripten
     and WASI platforms to work around missing *note os.pipe(): 190a. on
     WASI.

   - gh-89325(200): Removed many old deprecated *note unittest: 106.
     features: *note TestCase: 451. method aliases, undocumented and
     broken ‘TestCase’ method ‘assertDictContainsSubset’, undocumented
     *note TestLoader.loadTestsFromModule: 28f. parameter
     'use_load_tests', and an underscored alias of the *note
     TextTestResult: 534. class.

   - gh-92734(201): Allow multi-element reprs emitted by *note reprlib:
     bb. to be pretty-printed using configurable indentation.

   - gh-92671(202): Fixed *note ast.unparse(): 8ee. for empty tuples in
     the assignment target context.

   - gh-91581(203): *note utcfromtimestamp(): 2fd. no longer attempts to
     resolve ‘fold’ in the pure Python implementation, since the fold is
     never 1 in UTC. In addition to being slightly faster in the common
     case, this also prevents some errors when the timestamp is close to
     *note datetime.min: 190b.  Patch by Paul Ganssle.

   - gh-86388(204): Removed randrange() functionality deprecated since
     Python 3.10.  Formerly, randrange(10.0) losslessly converted to
     randrange(10).  Now, it raises a TypeError.  Also, the exception
     raised for non-integral values such as randrange(10.5) or
     randrange(‘10’) has been changed from ValueError to TypeError.

   - gh-90385(205): Add *note pathlib.Path.walk(): 4ab. as an
     alternative to *note os.walk(): 4ac.

   - gh-92550(206): Fix *note pathlib.Path.rglob(): 22e. for empty
     pattern.

   - gh-92591(207): Allow *note logging: 87. filters to return a *note
     logging.LogRecord: 1021. instance so that filters attached to *note
     logging.Handler: 14e5.s can enrich records without side effects on
     other handlers.

   - gh-92445(208): Fix a bug in *note argparse: 6. where ‘nargs="*"’
     would raise an error instead of returning an empty list when 0
     arguments were supplied if choice was also defined in
     ‘parser.add_argument’.

   - gh-92547(209): Remove undocumented *note sqlite3: cf. features
     deprecated in Python 3.10:

        * ‘sqlite3.enable_shared_cache()’

        * ‘sqlite3.OptimizedUnicode’

     Patch by Erlend E. Aasland.

   - gh-92530(210): Fix an issue that occurred after interrupting *note
     threading.Condition.notify(): 190c.

   - gh-92531(211): The statistics.median_grouped() function now always
     return a float.  Formerly, it did not convert the input type when
     for sequences of length one.

   - gh-84131(212): The *note pathlib.Path: 229. deprecated method
     ‘link_to’ has been removed.  Use 3.10’s *note hardlink_to(): 827.
     method instead as its semantics are consistent with that of *note
     symlink_to(): 828.

   - gh-89336(213): Removed *note configparser: 22. module APIs: the
     ‘SafeConfigParser’ class alias, the ‘ParsingError.filename’
     property and parameter, and the ‘ConfigParser.readfp’ method, all
     of which were deprecated since Python 3.2.

   - gh-92391(214): Add *note __class_getitem__(): 73e. to *note
     csv.DictReader: 9f0. and *note csv.DictWriter: 1243, allowing them
     to be parameterized at runtime.  Patch by Marc Mueller.

   - gh-91968(215): Add ‘SO_RTABLE’ and ‘SO_USER_COOKIE’ constants to
     *note socket: cc.

   - gh-91810(216): *note ElementTree: 958. method *note write(): aaa.
     and function *note tostring(): 1030. now use the text file’s
     encoding (“UTF-8” if not available) instead of locale encoding in
     XML declaration when ‘encoding="unicode"’ is specified.

   - gh-81790(217): *note os.path.splitdrive(): c15. now understands DOS
     device paths with UNC links (beginning ‘\\?\UNC\’).  Contributed by
     Barney Gale.

   - gh-91760(218): Apply more strict rules for numerical group
     references and group names in regular expressions.  Only sequence
     of ASCII digits is now accepted as a numerical reference.  The
     group name in bytes patterns and replacement strings can now only
     contain ASCII letters and digits and underscore.

   - gh-90622(219): Worker processes for *note
     concurrent.futures.ProcessPoolExecutor: 8f7. are no longer spawned
     on demand (a feature added in 3.9) when the multiprocessing context
     start method is ‘"fork"’ as that can lead to deadlocks in the child
     processes due to a fork happening while threads are running.

   - gh-91577(220): Move imports in ‘SharedMemory’ methods to module
     level so that they can be executed late in python finalization.

   - gh-91581(221): Remove an unhandled error case in the C
     implementation of calls to *note datetime.fromtimestamp: 4f0. with
     no time zone (i.e.  getting a local time from an epoch timestamp).
     This should have no user-facing effect other than giving a possibly
     more accurate error message when called with timestamps that fall
     on 10000-01-01 in the local time.  Patch by Paul Ganssle.

   - gh-91539(222): Improve performance of
     ‘urllib.request.getproxies_environment’ when there are many
     environment variables

   - gh-91524(223): Speed up the regular expression substitution
     (functions *note re.sub(): 2a3. and *note re.subn(): 2a4. and
     corresponding *note re.Pattern: 190d. methods) for replacement
     strings containing group references by 2–3 times.

   - gh-91447(224): Fix findtext in the xml module to only give an empty
     string when the text attribute is set to ‘None’.

   - gh-91456(225): Deprecate current default auto() behavior: In 3.13
     the default will be for for auto() to always return the largest
     member value incremented by 1, and to raise if incompatible value
     types are used.

   - bpo-47231(226): Fixed an issue with inconsistent trailing slashes
     in tarfile longname directories.

   - bpo-39064(227): *note zipfile.ZipFile: 6c7. now raises *note
     zipfile.BadZipFile: 190e. instead of ‘ValueError’ when reading a
     corrupt zip file in which the central directory offset is negative.

   - bpo-41287(228): Fix handling of the ‘doc’ argument in subclasses of
     *note property(): 194.

   - gh-90005(229): *note ctypes: 2a. dependency ‘libffi’ is now
     detected with ‘pkg-config’.

   - bpo-32547(230): The constructors for *note DictWriter: 1243. and
     *note DictReader: 9f0. now coerce the ‘fieldnames’ argument to a
     *note list: 614. if it is an iterator.

   - bpo-35540(231): Fix *note dataclasses.asdict(): 1836. crash when
     *note collections.defaultdict: 1201. is present in the attributes.

   - bpo-47063(232): Add an index_pages parameter to support using
     non-default index page names.

   - bpo-47025(233): Drop support for *note bytes: 1c2. on *note
     sys.path: 3b7.

   - bpo-46951(234): Order the contents of zipapp archives, to make
     builds more reproducible.

   - bpo-42777(235): Implement *note pathlib.Path.is_mount(): a24. for
     Windows paths.

   - bpo-46755(236): In ‘QueueHandler’, clear ‘stack_info’ from
     ‘LogRecord’ to prevent stack trace from being written twice.

   - bpo-45393(237): Fix the formatting for ‘await x’ and ‘not x’ in the
     operator precedence table when using the *note help(): 8e0. system.

   - bpo-46642(238): Improve error message when trying to subclass an
     instance of *note typing.TypeVar: 15d, *note typing.ParamSpec: 15e,
     *note typing.TypeVarTuple: 15f, etc.  Based on patch by Gregory
     Beauregard.

   - bpo-46364(239): Restrict use of sockets instead of pipes for stdin
     of subprocesses created by *note asyncio: a. to AIX platform only.

   - bpo-28249(240): Set *note doctest.DocTest.lineno: 1626. to ‘None’
     when an object does not have *note __doc__: 931.

   - bpo-46197(241): Fix *note ensurepip: 55. environment isolation for
     subprocess running ‘pip’.

   - bpo-45924(242): Fix *note asyncio: a. incorrect traceback when
     future’s exception is raised multiple times.  Patch by Kumar
     Aditya.

   - bpo-45046(243): Add support of context managers in *note unittest:
     106.: methods *note enterContext(): 6bc. and *note
     enterClassContext(): 6bd. of class *note TestCase: 451, method
     *note enterAsyncContext(): 6be. of class *note
     IsolatedAsyncioTestCase: 30c. and function *note
     unittest.enterModuleContext(): 6bf.

   - bpo-44173(244): Enable fast seeking of uncompressed unencrypted
     ‘zipfile.ZipExtFile’

   - bpo-42627(245): Fix incorrect parsing of Windows registry proxy
     settings

   - bpo-42047(246): Add *note threading.get_native_id(): a4b. support
     for DragonFly BSD. Patch by David Carlier.

   - bpo-14243(247): The *note tempfile.NamedTemporaryFile: 4c9.
     function has a new optional parameter 'delete_on_close'

   - bpo-41246(248): Give the same callback function for when the
     overlapped operation is done to the functions ‘recv’, ‘recv_into’,
     ‘recvfrom’, ‘sendto’, ‘send’ and ‘sendfile’ inside ‘IocpProactor’.

   - bpo-39264(249): Fixed ‘collections.UserDict.get()’ to not call
     *note __missing__(): 1202. when a value is not found.  This matches
     the behavior of *note dict: 256.  Patch by Bar Harel.

   - bpo-38693(250): *note importlib: 77. now uses f-strings internally
     instead of ‘str.format’.

   - bpo-38267(251): Add 'timeout' parameter to *note
     asyncio.loop.shutdown_default_executor(): 8f0.  The default value
     is ‘None’, which means the executor will be given an unlimited
     amount of time.  When called from *note asyncio.Runner: 603. or
     *note asyncio.run(): 47f, the default timeout is 5 minutes.

   - bpo-34828(252): *note sqlite3.Connection.iterdump(): 247. now
     handles databases that use ‘AUTOINCREMENT’ in one or more tables.

   - bpo-32990(253): Support reading wave files with the
     ‘WAVE_FORMAT_EXTENSIBLE’ format in the *note wave: 113. module.

   - bpo-26253(254): Allow adjustable compression level for tarfile
     streams in *note tarfile.open(): eab.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89237

   (2) https://github.com/python/cpython/issues/97928

   (3) https://github.com/python/cpython/issues/98393

   (4) https://github.com/python/cpython/issues/98363

   (5) https://github.com/python/cpython/issues/98331

   (6) https://github.com/python/cpython/issues/98307

   (7) https://github.com/python/cpython/issues/96035

   (8) https://github.com/python/cpython/issues/98257

   (9) https://github.com/python/cpython/issues/98251

   (10) https://github.com/python/cpython/issues/94597

   (11) https://github.com/python/cpython/issues/98178

   (12) https://github.com/python/cpython/issues/44098

   (13) https://github.com/python/cpython/issues/87730

   (14) https://github.com/python/cpython/issues/94597

   (15) https://github.com/python/cpython/issues/98023

   (16) https://github.com/python/cpython/issues/90985

   (17) https://github.com/python/cpython/issues/65961

   (18) https://github.com/python/cpython/issues/97646

   (19) https://datatracker.ietf.org/doc/html/rfc9239.html

   (20) https://github.com/python/cpython/issues/97930

   (21) https://github.com/python/cpython/issues/97850

   (22) https://github.com/python/cpython/issues/97837

   (23) https://github.com/python/cpython/issues/97825

   (24) https://github.com/python/cpython/issues/97008

   (25) https://github.com/python/cpython/issues/82711

   (26) https://github.com/python/cpython/issues/97799

   (27) https://github.com/python/cpython/issues/97781

   (28) https://github.com/python/cpython/issues/96827

   (29) https://github.com/python/cpython/issues/95534

   (30) https://github.com/python/cpython/issues/97592

   (31) https://github.com/python/cpython/issues/97639

   (32) https://github.com/python/cpython/issues/97545

   (33) https://github.com/python/cpython/issues/73588

   (34) https://github.com/python/cpython/issues/96865

   (35) https://github.com/python/cpython/issues/97005

   (36) https://github.com/python/cpython/issues/85760

   (37) https://github.com/python/cpython/issues/96704

   (38) https://github.com/python/cpython/issues/96819

   (39) https://github.com/python/cpython/issues/95865

   (40) https://github.com/python/cpython/issues/96741

   (41) https://github.com/python/cpython/issues/96734

   (42) https://github.com/python/cpython/issues/96735

   (43) https://github.com/python/cpython/issues/46412

   (44) https://github.com/python/cpython/issues/96652

   (45) https://github.com/python/cpython/issues/68163

   (46) https://github.com/python/cpython/issues/96538

   (47) https://github.com/python/cpython/issues/96465

   (48) https://github.com/python/cpython/issues/96079

   (49) https://github.com/python/cpython/issues/96415

   (50) https://github.com/python/cpython/issues/95987

   (51) https://github.com/python/cpython/issues/96388

   (52) https://github.com/python/cpython/issues/96385

   (53) https://github.com/python/cpython/issues/96142

   (54) https://github.com/python/cpython/issues/96073

   (55) https://github.com/python/cpython/issues/89258

   (56) https://github.com/python/cpython/issues/96346

   (57) https://github.com/python/cpython/issues/96349

   (58) https://github.com/python/cpython/issues/90467

   (59) https://github.com/python/cpython/issues/96172

   (60) https://github.com/python/cpython/issues/96159

   (61) https://github.com/python/cpython/issues/96175

   (62) https://github.com/python/cpython/issues/96145

   (63) https://github.com/python/cpython/issues/96052

   (64) https://github.com/python/cpython/issues/96125

   (65) https://github.com/python/cpython/issues/96019

   (66) https://github.com/python/cpython/issues/95463

   (67) https://bugs.python.org/issue?@action=redirect&bpo=28080

   (68) https://github.com/python/cpython/issues/69142

   (69) https://github.com/python/cpython/issues/95899

   (70) https://github.com/python/cpython/issues/95736

   (71) https://github.com/python/cpython/issues/95865

   (72) https://github.com/python/cpython/issues/95861

   (73) https://github.com/python/cpython/issues/95804

   (74) https://github.com/python/cpython/issues/95704

   (75) https://github.com/python/cpython/issues/95149

   (76) https://github.com/python/cpython/issues/95609

   (77) https://github.com/python/cpython/issues/95289

   (78) https://github.com/python/cpython/issues/94909

   (79) https://github.com/python/cpython/issues/95385

   (80) https://github.com/python/cpython/issues/83901

   (81) https://github.com/python/cpython/issues/95339

   (82) https://github.com/python/cpython/issues/95045

   (83) https://github.com/python/cpython/issues/95231

   (84) https://github.com/python/cpython/issues/95097

   (85) https://github.com/python/cpython/issues/95087

   (86) https://github.com/python/cpython/issues/95199

   (87) https://github.com/python/cpython/issues/95194

   (88) https://github.com/python/cpython/issues/93899

   (89) https://github.com/python/cpython/issues/95166

   (90) https://github.com/python/cpython/issues/95132

   (91) https://github.com/python/cpython/issues/85128

   (92) https://github.com/python/cpython/issues/93157

   (93) https://github.com/python/cpython/issues/91212

   (94) https://github.com/python/cpython/issues/95077

   (95) https://github.com/python/cpython/issues/95109

   (96) https://github.com/python/cpython/issues/95105

   (97) https://github.com/python/cpython/issues/95066

   (98) https://github.com/python/cpython/issues/77617

   (99) https://github.com/python/cpython/issues/95005

   (100) https://github.com/python/cpython/issues/90085

   (101) https://github.com/python/cpython/issues/94857

   (102) https://github.com/python/cpython/issues/94821

   (103) https://github.com/python/cpython/issues/94736

   (104) https://github.com/python/cpython/issues/81620

   (105) https://github.com/python/cpython/issues/74116

   (106) https://github.com/python/cpython/issues/87822

   (107) https://github.com/python/cpython/issues/88050

   (108) https://github.com/python/cpython/issues/94637

   (109) https://github.com/python/cpython/issues/94309

   (110) https://github.com/python/cpython/issues/92546

   (111) https://github.com/python/cpython/issues/94607

   (112) https://github.com/python/cpython/issues/94619

   (113) https://github.com/python/cpython/issues/93910

   (114) https://github.com/python/cpython/issues/93896

   (115) https://github.com/python/cpython/issues/94343

   (116) https://github.com/python/cpython/issues/94382

   (117) https://github.com/python/cpython/issues/78724

   (118) https://github.com/python/cpython/issues/94510

   (119) https://github.com/python/cpython/issues/92336

   (120) https://github.com/python/cpython/issues/94398

   (121) https://github.com/python/cpython/issues/94383

   (122) https://github.com/python/cpython/issues/94379

   (123) https://peps.python.org/pep-0451/

   (124) https://github.com/python/cpython/issues/94352

   (125) https://github.com/python/cpython/issues/94318

   (126) https://github.com/python/cpython/issues/89988

   (127) https://github.com/python/cpython/issues/90016

   (128) https://github.com/python/cpython/issues/94254

   (129) https://github.com/python/cpython/issues/93259

   (130) https://github.com/python/cpython/issues/74696

   (131) https://github.com/python/cpython/issues/94216

   (132) https://github.com/python/cpython/issues/93096

   (133) https://github.com/python/cpython/issues/94207

   (134) https://github.com/python/cpython/issues/93096

   (135) https://github.com/python/cpython/issues/94226

   (136) https://github.com/python/cpython/issues/94199

   (137) https://github.com/python/cpython/issues/94214

   (138) https://github.com/python/cpython/issues/94199

   (139) https://cwe.mitre.org/data/definitions/295.html

   (140) https://github.com/python/cpython/issues/94199

   (141) https://github.com/python/cpython/issues/94199

   (142) https://peps.python.org/pep-0644/

   (143) https://github.com/python/cpython/issues/94196

   (144) https://github.com/python/cpython/issues/94182

   (145) https://github.com/python/cpython/issues/94169

   (146) https://github.com/python/cpython/issues/91742

   (147) https://github.com/python/cpython/issues/94101

   (148) https://github.com/python/cpython/issues/84753

   (149) https://github.com/python/cpython/issues/94028

   (150) https://github.com/python/cpython/issues/93973

   (151) https://github.com/python/cpython/issues/93963

   (152) https://github.com/python/cpython/issues/93858

   (153) https://github.com/python/cpython/issues/93820

   (154) https://github.com/python/cpython/issues/93847

   (155) https://github.com/python/cpython/issues/91404

   (156) https://github.com/python/cpython/issues/83499

   (157) https://github.com/python/cpython/issues/93820

   (158) https://github.com/python/cpython/issues/79512

   (159) https://github.com/python/cpython/issues/91389

   (160) https://github.com/python/cpython/issues/93626

   (161) https://github.com/python/cpython/issues/90473

   (162) https://peps.python.org/pep-0370/

   (163) https://github.com/python/cpython/issues/90494

   (164) https://github.com/python/cpython/issues/90549

   (165) https://github.com/python/cpython/issues/93521

   (166) https://github.com/python/cpython/issues/79579

   (167) https://github.com/python/cpython/issues/93421

   (168) https://github.com/python/cpython/issues/93475

   (169) https://github.com/python/cpython/issues/93370

   (170) https://github.com/python/cpython/issues/91810

   (171) https://github.com/python/cpython/issues/91162

   (172) https://github.com/python/cpython/issues/93353

   (173) https://github.com/python/cpython/issues/83658

   (174) https://github.com/python/cpython/issues/93312

   (175) https://github.com/python/cpython/issues/88123

   (176) https://github.com/python/cpython/issues/93297

   (177) https://github.com/python/cpython/issues/85308

   (178) https://github.com/python/cpython/issues/93156

   (179) https://github.com/python/cpython/issues/93162

   (180) https://github.com/python/cpython/issues/93243

   (181) https://peps.python.org/pep-0594/

   (182) https://github.com/python/cpython/issues/92886

   (183) https://github.com/python/cpython/issues/90155

   (184) https://github.com/python/cpython/issues/90817

   (185) https://github.com/python/cpython/issues/91513

   (186) https://github.com/python/cpython/issues/74696

   (187) https://github.com/python/cpython/issues/92728

   (188) https://github.com/python/cpython/issues/93033

   (189) https://github.com/python/cpython/issues/89973

   (190) https://github.com/python/cpython/issues/93044

   (191) https://github.com/python/cpython/issues/93010

   (192) https://github.com/python/cpython/issues/92986

   (193) https://github.com/python/cpython/issues/92932

   (194) https://github.com/python/cpython/issues/92675

   (195) https://github.com/python/cpython/issues/87901

   (196) https://github.com/python/cpython/issues/91922

   (197) https://github.com/python/cpython/issues/92869

   (198) https://github.com/python/cpython/issues/92839

   (199) https://github.com/python/cpython/issues/90473

   (200) https://github.com/python/cpython/issues/89325

   (201) https://github.com/python/cpython/issues/92734

   (202) https://github.com/python/cpython/issues/92671

   (203) https://github.com/python/cpython/issues/91581

   (204) https://github.com/python/cpython/issues/86388

   (205) https://github.com/python/cpython/issues/90385

   (206) https://github.com/python/cpython/issues/92550

   (207) https://github.com/python/cpython/issues/92591

   (208) https://github.com/python/cpython/issues/92445

   (209) https://github.com/python/cpython/issues/92547

   (210) https://github.com/python/cpython/issues/92530

   (211) https://github.com/python/cpython/issues/92531

   (212) https://github.com/python/cpython/issues/84131

   (213) https://github.com/python/cpython/issues/89336

   (214) https://github.com/python/cpython/issues/92391

   (215) https://github.com/python/cpython/issues/91968

   (216) https://github.com/python/cpython/issues/91810

   (217) https://github.com/python/cpython/issues/81790

   (218) https://github.com/python/cpython/issues/91760

   (219) https://github.com/python/cpython/issues/90622

   (220) https://github.com/python/cpython/issues/91577

   (221) https://github.com/python/cpython/issues/91581

   (222) https://github.com/python/cpython/issues/91539

   (223) https://github.com/python/cpython/issues/91524

   (224) https://github.com/python/cpython/issues/91447

   (225) https://github.com/python/cpython/issues/91456

   (226) https://bugs.python.org/issue?@action=redirect&bpo=47231

   (227) https://bugs.python.org/issue?@action=redirect&bpo=39064

   (228) https://bugs.python.org/issue?@action=redirect&bpo=41287

   (229) https://github.com/python/cpython/issues/90005

   (230) https://bugs.python.org/issue?@action=redirect&bpo=32547

   (231) https://bugs.python.org/issue?@action=redirect&bpo=35540

   (232) https://bugs.python.org/issue?@action=redirect&bpo=47063

   (233) https://bugs.python.org/issue?@action=redirect&bpo=47025

   (234) https://bugs.python.org/issue?@action=redirect&bpo=46951

   (235) https://bugs.python.org/issue?@action=redirect&bpo=42777

   (236) https://bugs.python.org/issue?@action=redirect&bpo=46755

   (237) https://bugs.python.org/issue?@action=redirect&bpo=45393

   (238) https://bugs.python.org/issue?@action=redirect&bpo=46642

   (239) https://bugs.python.org/issue?@action=redirect&bpo=46364

   (240) https://bugs.python.org/issue?@action=redirect&bpo=28249

   (241) https://bugs.python.org/issue?@action=redirect&bpo=46197

   (242) https://bugs.python.org/issue?@action=redirect&bpo=45924

   (243) https://bugs.python.org/issue?@action=redirect&bpo=45046

   (244) https://bugs.python.org/issue?@action=redirect&bpo=44173

   (245) https://bugs.python.org/issue?@action=redirect&bpo=42627

   (246) https://bugs.python.org/issue?@action=redirect&bpo=42047

   (247) https://bugs.python.org/issue?@action=redirect&bpo=14243

   (248) https://bugs.python.org/issue?@action=redirect&bpo=41246

   (249) https://bugs.python.org/issue?@action=redirect&bpo=39264

   (250) https://bugs.python.org/issue?@action=redirect&bpo=38693

   (251) https://bugs.python.org/issue?@action=redirect&bpo=38267

   (252) https://bugs.python.org/issue?@action=redirect&bpo=34828

   (253) https://bugs.python.org/issue?@action=redirect&bpo=32990

   (254) https://bugs.python.org/issue?@action=redirect&bpo=26253


File: python.info,  Node: Documentation<26>,  Next: Tests<29>,  Prev: Library<63>,  Up: Python 3 12 0 alpha 1

1.23.35.22 Documentation
........................

   - gh-85525(1): Remove extra row

   - gh-86404(2): Deprecated tools ‘make suspicious’ and ‘rstlint.py’
     are now removed.  They have been replaced by sphinx-lint(3).

   - gh-97741(4): Fix ‘!’ in c domain ref target syntax via a ‘conf.py’
     patch, so it works as intended to disable ref target resolution.

   - gh-96432(5): Fraction literals now support whitespace around the
     forward slash, ‘Fraction('2 / 3')’.

   - gh-96098(6): Improve discoverability of the higher level
     concurrent.futures module by providing clearer links from the lower
     level threading and multiprocessing modules.

   - gh-95957(7): What’s New 3.11 now has instructions for how to
     provide compiler and linker flags for Tcl/Tk and OpenSSL on RHEL 7
     and CentOS 7.

   - gh-95588(8): Clarified the conflicting advice given in the *note
     ast: 8. documentation about *note ast.literal_eval(): c38. being
     “safe” for use on untrusted input while at the same time warning
     that it can crash the process.  The latter statement is true and is
     deemed unfixable without a large amount of work unsuitable for a
     bugfix.  So we keep the warning and no longer claim that
     ‘literal_eval’ is safe.

   - gh-91207(9): Fix stylesheet not working in Windows CHM htmlhelp
     docs and add warning that they are deprecated.  Contributed by
     C.A.M. Gerlach.

   - gh-95454(10): Replaced incorrectly written true/false values in
     documentation.  Patch by Robert O’Shea

   - gh-95451(11): Update library documentation with *note availability
     information: 1910. on WebAssembly platforms ‘wasm32-emscripten’ and
     ‘wasm32-wasi’.

   - gh-95415(12): Use consistent syntax for platform availability.  The
     directive now supports a content body and emits a warning when it
     encounters an unknown platform.

   - gh-94321(13): Document the PEP 246(14) style protocol type *note
     sqlite3.PrepareProtocol: 1911.

   - gh-86128(15): Document a limitation in ThreadPoolExecutor where its
     exit handler is executed before any handlers in atexit.

   - gh-61162(16): Clarify *note sqlite3: cf. behavior when *note How to
     use the connection context manager: 1912.

   - gh-87260(17): Align *note sqlite3: cf. argument specs with the
     actual implementation.

   - gh-86986(18): The minimum Sphinx version required to build the
     documentation is now 3.2.

   - gh-88831(19): Augmented documentation of asyncio.create_task().
     Clarified the need to keep strong references to tasks and added a
     code snippet detailing how to do this.

   - gh-86438(20): Clarify that *note -W: 8d0. and *note PYTHONWARNINGS:
     bc8. are matched literally and case-insensitively, rather than as
     regular expressions, in *note warnings: 112.

   - gh-93031(21): Update tutorial introduction output to use 3.10+
     SyntaxError invalid range.

   - gh-92240(22): Added release dates for “What’s New in Python 3.X”
     for 3.0, 3.1, 3.2, 3.8 and 3.10

   - bpo-47161(23): Document that *note pathlib.PurePath: 4a9. does not
     collapse initial double slashes because they denote UNC paths.

   - bpo-40838(24): Document that *note inspect.getdoc(): a05, *note
     inspect.getmodule(): 1913, and *note inspect.getsourcefile(): 1914.
     might return ‘None’.

   - bpo-43689(25): The ‘Differ’ documentation now also mentions other
     whitespace characters, which make it harder to understand the diff
     output.

   - bpo-38056(26): Overhaul the *note Error Handlers: 1915.
     documentation in *note codecs: 1b.

   - bpo-13553(27): Document tkinter.Tk args.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/85525

   (2) https://github.com/python/cpython/issues/86404

   (3) https://pypi.org/project/sphinx-lint/

   (4) https://github.com/python/cpython/issues/97741

   (5) https://github.com/python/cpython/issues/96432

   (6) https://github.com/python/cpython/issues/96098

   (7) https://github.com/python/cpython/issues/95957

   (8) https://github.com/python/cpython/issues/95588

   (9) https://github.com/python/cpython/issues/91207

   (10) https://github.com/python/cpython/issues/95454

   (11) https://github.com/python/cpython/issues/95451

   (12) https://github.com/python/cpython/issues/95415

   (13) https://github.com/python/cpython/issues/94321

   (14) https://peps.python.org/pep-0246/

   (15) https://github.com/python/cpython/issues/86128

   (16) https://github.com/python/cpython/issues/61162

   (17) https://github.com/python/cpython/issues/87260

   (18) https://github.com/python/cpython/issues/86986

   (19) https://github.com/python/cpython/issues/88831

   (20) https://github.com/python/cpython/issues/86438

   (21) https://github.com/python/cpython/issues/93031

   (22) https://github.com/python/cpython/issues/92240

   (23) https://bugs.python.org/issue?@action=redirect&bpo=47161

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40838

   (25) https://bugs.python.org/issue?@action=redirect&bpo=43689

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38056

   (27) https://bugs.python.org/issue?@action=redirect&bpo=13553


File: python.info,  Node: Tests<29>,  Next: Build<31>,  Prev: Documentation<26>,  Up: Python 3 12 0 alpha 1

1.23.35.23 Tests
................

   - gh-95027(1): On Windows, when the Python test suite is run with the
     ‘-jN’ option, the ANSI code page is now used as the encoding for
     the stdout temporary file, rather than using UTF-8 which can lead
     to decoding errors.  Patch by Victor Stinner.

   - gh-96624(2): Fixed the failure of repeated runs of
     ‘test.test_unittest’ caused by side effects in
     ‘test_dotted_but_module_not_loaded’.

   - gh-95243(3): Mitigate the inherent race condition from using
     find_unused_port() in testSockName() by trying to find an unused
     port a few times before failing.  Patch by Ross Burton.

   - gh-95573(4): Lib/test/test_asyncio/test_ssl.py(5) exposed a bug in
     the macOS kernel where intense concurrent load on non-blocking
     sockets occasionally causes *note errno.ENOBUFS: 1917. (“No buffer
     space available”) to be emitted.  FB11063974 filed with Apple, in
     the mean time as a workaround buffer size used in tests on macOS is
     decreased to avoid intermittent failures.  Patch by Fantix King.

   - gh-95280(6): Fix problem with ‘test_ssl’ ‘test_get_ciphers’ on
     systems that require perfect forward secrecy (PFS) ciphers.

   - gh-95212(7): Make multiprocessing test case
     ‘test_shared_memory_recreate’ parallel-safe.

   - gh-95218(8): Move tests for importlib.resources into
     test_importlib.resources.

   - gh-93963(9): Updated tests to use preferred location for
     ‘importlib.resources’ ABCs.

   - gh-94675(10): Add a regression test for *note re: b9. exponentional
     slowdown when using rjsmin.

   - gh-91330(11): Added more tests for *note dataclasses: 2f. to cover
     behavior with data descriptor-based fields.

   - gh-94208(12): ‘test_ssl’ is now checking for supported TLS version
     and protocols in more tests.

   - gh-94315(13): Tests now check for DAC override capability instead
     of relying on *note os.geteuid(): 1918.

   - gh-54781(14): Rename test_tk to test_tkinter, and rename
     test_ttk_guionly to test_ttk.  Patch by Victor Stinner.

   - gh-93839(15): Move ‘Lib/ctypes/test/’ to ‘Lib/test/test_ctypes/’.
     Patch by Victor Stinner.

   - gh-93951(16): In test_bdb.StateTestCase.test_skip, avoid including
     auxiliary importers.

   - gh-93957(17): Provide nicer error reporting from subprocesses in
     test_venv.EnsurePipTest.test_with_pip.

   - gh-93884(18): Add test cases for *note PyNumber_ToBase(): 1919.
     that take a large number or a non-int object as parameter.

   - gh-93852(19): test_asyncio, test_logging, test_socket and
     test_socketserver now create AF_UNIX domains in the current
     directory to no longer fail with ‘OSError("AF_UNIX path too long")’
     if the temporary directory (the ‘TMPDIR’ environment variable) is
     too long.  Patch by Victor Stinner.

   - gh-93353(20): regrtest now checks if a test leaks temporary files
     or directories if run with -jN option.  Patch by Victor Stinner.

   - gh-84461(21): ‘run_tests.py’ now handles cross compiling env vars
     correctly and pass ‘HOSTRUNNER’ to regression tests.

   - gh-93616(22): ‘test_modulefinder’ now creates a temporary directory
     in ‘ModuleFinderTest.setUp()’ instead of module scope.

   - gh-93575(23): Fix issue with test_unicode test_raiseMemError.  The
     test case now use ‘test.support.calcobjsize’ to calculate size of
     PyUnicode structs.  *note sys.getsizeof(): 187e. may return
     different size when string has UTF-8 memory.

   - gh-90473(24): WASI does not have a ‘chmod(2)’ syscall.  *note
     os.chmod(): 21b. is now a dummy function on WASI. Skip all tests
     that depend on working ‘os.chmod()’.

   - gh-90473(25): Skip tests on WASI that require symlinks with
     absolute paths.

   - gh-57539(26): Increase calendar test coverage for
     ‘calendar.LocaleTextCalendar.formatweekday()’.

   - gh-90473(27): Skip symlink tests on WASI. wasmtime uses
     ‘openat2(2)’ with ‘RESOLVE_BENEATH’ flag, which prevents symlinks
     with absolute paths.

   - gh-89858(28): Fix ‘test_embed’ for out-of-tree builds.  Patch by
     Kumar Aditya.

   - gh-92886(29): Fixing tests that fail when running with
     optimizations (‘-O’) in ‘test_imaplib.py’.

   - gh-92886(30): Fixing tests that fail when running with
     optimizations (‘-O’) in ‘test_zipimport.py’

   - gh-92886(31): Fixing tests that fail when running with
     optimizations (‘-O’) in ‘test_py_compile.py’

   - gh-92886(32): Fixing tests that fail when running with
     optimizations (‘-O’) in ‘test_sys_settrace.py’.

   - gh-92886(33): Fixing tests that fail when running with
     optimizations (‘-O’) in ‘_test_multiprocessing.py’

   - gh-92670(34): Skip
     ‘test_shutil.TestCopy.test_copyfile_nonexistent_dir’ test on AIX as
     the test uses a trailing slash to force the OS consider the path as
     a directory, but on AIX the trailing slash has no effect and is
     considered as a file.

   - gh-92514(35): Remove unused ‘test.support.BasicTestRunner’.  Patch
     by Jelle Zijlstra.

   - bpo-47016(36): Create a GitHub Actions workflow for verifying
     bundled pip and setuptools.  Patch by Illia Volochii and Adam
     Turner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/95027

   (2) https://github.com/python/cpython/issues/96624

   (3) https://github.com/python/cpython/issues/95243

   (4) https://github.com/python/cpython/issues/95573

   (5) 
https://github.com/python/cpython/tree/3.13/Lib/test/test_asyncio/test_ssl.py

   (6) https://github.com/python/cpython/issues/95280

   (7) https://github.com/python/cpython/issues/95212

   (8) https://github.com/python/cpython/issues/95218

   (9) https://github.com/python/cpython/issues/93963

   (10) https://github.com/python/cpython/issues/94675

   (11) https://github.com/python/cpython/issues/91330

   (12) https://github.com/python/cpython/issues/94208

   (13) https://github.com/python/cpython/issues/94315

   (14) https://github.com/python/cpython/issues/54781

   (15) https://github.com/python/cpython/issues/93839

   (16) https://github.com/python/cpython/issues/93951

   (17) https://github.com/python/cpython/issues/93957

   (18) https://github.com/python/cpython/issues/93884

   (19) https://github.com/python/cpython/issues/93852

   (20) https://github.com/python/cpython/issues/93353

   (21) https://github.com/python/cpython/issues/84461

   (22) https://github.com/python/cpython/issues/93616

   (23) https://github.com/python/cpython/issues/93575

   (24) https://github.com/python/cpython/issues/90473

   (25) https://github.com/python/cpython/issues/90473

   (26) https://github.com/python/cpython/issues/57539

   (27) https://github.com/python/cpython/issues/90473

   (28) https://github.com/python/cpython/issues/89858

   (29) https://github.com/python/cpython/issues/92886

   (30) https://github.com/python/cpython/issues/92886

   (31) https://github.com/python/cpython/issues/92886

   (32) https://github.com/python/cpython/issues/92886

   (33) https://github.com/python/cpython/issues/92886

   (34) https://github.com/python/cpython/issues/92670

   (35) https://github.com/python/cpython/issues/92514

   (36) https://bugs.python.org/issue?@action=redirect&bpo=47016


File: python.info,  Node: Build<31>,  Next: Windows<27>,  Prev: Tests<29>,  Up: Python 3 12 0 alpha 1

1.23.35.24 Build
................

   - gh-96761(1): Fix the build process of clang compiler for
     ‘_bootstrap_python’ if LTO optimization is applied.  Patch by
     Matthias Görgens and Donghee Na.

   - gh-96883(2): ‘wasm32-emscripten’ builds for browsers now include
     *note concurrent.futures: 21. for *note asyncio: a. and *note
     unittest.mock: 107.

   - gh-85936(3): CPython now uses the ThinLTO option as the default
     policy if the Clang compiler accepts the flag.  Patch by Donghee
     Na.

   - gh-96729(4): Ensure that Windows releases built with
     ‘Tools\msi\buildrelease.bat’ are upgradable to and from official
     Python releases.

   - gh-96269(5): Shared module targets now depend on new ‘MODULE_DEPS’
     variable, which includes ‘EXPORTSYMS’.  This fixes a build order
     issue on unsupported AIX platform.

   - gh-84461(6): ‘wasm32-emscripten’ platform no longer builds *note
     resource: bc. module, *note getresuid(): 135f, *note getresgid():
     135e, and their setters.  The APIs are stubs and not functional.

   - gh-95973(7): Add a new ‘--with-dsymutil’ configure option to link
     debug information in macOS. Patch by Pablo Galindo.

   - gh-90536(8): Use the BOLT post-link optimizer to improve
     performance, particularly on medium-to-large applications.

   - gh-93744(9): Remove the ‘configure --with-cxx-main’ build option:
     it didn’t work for many years.  Remove the ‘MAINCC’ variable from
     ‘configure’ and ‘Makefile’.  Patch by Victor Stinner.

   - gh-94801(10): Fix a regression in ‘configure’ script that caused
     some header checks to ignore custom ‘CPPFLAGS’.  The regression was
     introduced in gh-94802(11).

   - gh-95145(12): wasm32-wasi builds no longer depend on WASIX’s
     pthread stubs.  Python now has its own stubbed pthread API.

   - gh-95174(13): Python now detects missing ‘dup’ function in WASI and
     works around some missing *note errno: 57, *note select: c1, and
     *note socket: cc. constants.

   - gh-95174(14): Python now skips missing *note socket: cc. functions
     and methods on WASI. WASI can only create sockets from existing fd
     / accept and has no netdb.

   - gh-95085(15): Platforms ‘wasm32-unknown-emscripten’ and
     ‘wasm32-unknown-wasi’ have been promoted to PEP 11(16) tier 3
     platform support.

   - gh-94847(17): Fixed ‘_decimal’ module build issue on GCC when
     compiling with LTO and pydebug.  Debug builds no longer force
     inlining of functions.

   - gh-94841(18): Fix the possible performance regression of *note
     PyObject_Free(): c86. compiled with MSVC version 1932.

   - gh-94801(19): ‘configure’ now uses custom flags like ‘ZLIB_CFLAGS’
     and ‘ZLIB_LIBS’ when searching for headers and libraries.

   - gh-94773(20): ‘deepfreeze.py’ now supports code object with
     frozensets that contain incompatible, unsortable types.

   - gh-94682(21): Build and test with OpenSSL 1.1.1q

   - gh-90005(22): Dependencies of *note readline: ba. and *note curses:
     2b. module are now detected in ‘configure’ script with
     ‘pkg-config’.  Only ‘ncurses’ / ‘ncursesw’ are detected
     automatically.  The old ‘curses’ library is not configured
     automatically.  Workaround for missing ‘termcap’ or ‘tinfo’ library
     has been removed.

   - gh-90005(23): Fix building ‘_ctypes’ extension without
     ‘pkg-config’.

   - gh-90005(24): ‘_dbm’ module dependencies are now detected by
     configure.

   - gh-94404(25): ‘makesetup’ now works around an issue with sed on
     macOS and uses correct CFLAGS for object files that end up in a
     shared extension.  Module CFLAGS are used before
     PY_STDMODULE_CFLAGS to avoid clashes with system headers.

   - gh-93939(26): C extension modules are now built by ‘configure’ and
     ‘make’ instead of ‘distutils’ and ‘setup.py’.

   - gh-93939(27): The ‘2to3’, ‘idle’, and ‘pydoc’ scripts are now
     generated and installed by ‘Makefile’ instead of ‘setup.py’.

   - gh-94280(28): Updated pegen regeneration script on Windows to find
     and use Python 3.9 or higher.  Prior to this, pegen regeneration
     already required 3.9 or higher, but the script may have used lower
     versions of Python.

   - gh-93584(29): Address race condition in ‘Makefile’ when installing
     a PGO build.  All ‘test’ and ‘install’ targets now depend on ‘all’
     target.

   - gh-93491(30): ‘configure’ now detects and reports PEP 11(31)
     support tiers.

   - gh-69093(32): Fix ‘Modules/Setup.stdlib.in’ rule for ‘_sqlite3’
     extension.

   - gh-93207(33): ‘va_start()’ with two parameters, like
     ‘va_start(args, format),’ is now required to build Python.
     ‘va_start()’ is no longer called with a single parameter.  Patch by
     Kumar Aditya.

   - gh-93202(34): Python now always use the ‘%zu’ and ‘%zd’ printf
     formats to format a ‘size_t’ or ‘Py_ssize_t’ number.  Building
     Python 3.12 requires a C11 compiler, so these printf formats are
     now always supported.  Patch by Victor Stinner.

   - gh-90473(35): Disable pymalloc and increase stack size on
     ‘wasm32-wasi’.

   - bpo-34449(36): Drop invalid compiler switch ‘-fPIC’ for HP aCC on
     HP-UX. Patch by Michael Osipov.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/96761

   (2) https://github.com/python/cpython/issues/96883

   (3) https://github.com/python/cpython/issues/85936

   (4) https://github.com/python/cpython/issues/96729

   (5) https://github.com/python/cpython/issues/96269

   (6) https://github.com/python/cpython/issues/84461

   (7) https://github.com/python/cpython/issues/95973

   (8) https://github.com/python/cpython/issues/90536

   (9) https://github.com/python/cpython/issues/93744

   (10) https://github.com/python/cpython/issues/94801

   (11) https://github.com/python/cpython/issues/94802

   (12) https://github.com/python/cpython/issues/95145

   (13) https://github.com/python/cpython/issues/95174

   (14) https://github.com/python/cpython/issues/95174

   (15) https://github.com/python/cpython/issues/95085

   (16) https://peps.python.org/pep-0011/

   (17) https://github.com/python/cpython/issues/94847

   (18) https://github.com/python/cpython/issues/94841

   (19) https://github.com/python/cpython/issues/94801

   (20) https://github.com/python/cpython/issues/94773

   (21) https://github.com/python/cpython/issues/94682

   (22) https://github.com/python/cpython/issues/90005

   (23) https://github.com/python/cpython/issues/90005

   (24) https://github.com/python/cpython/issues/90005

   (25) https://github.com/python/cpython/issues/94404

   (26) https://github.com/python/cpython/issues/93939

   (27) https://github.com/python/cpython/issues/93939

   (28) https://github.com/python/cpython/issues/94280

   (29) https://github.com/python/cpython/issues/93584

   (30) https://github.com/python/cpython/issues/93491

   (31) https://peps.python.org/pep-0011/

   (32) https://github.com/python/cpython/issues/69093

   (33) https://github.com/python/cpython/issues/93207

   (34) https://github.com/python/cpython/issues/93202

   (35) https://github.com/python/cpython/issues/90473

   (36) https://bugs.python.org/issue?@action=redirect&bpo=34449


File: python.info,  Node: Windows<27>,  Next: macOS<20>,  Prev: Build<31>,  Up: Python 3 12 0 alpha 1

1.23.35.25 Windows
..................

   - gh-98360(1): Fixes *note multiprocessing: 94. spawning child
     processes on Windows from a virtual environment to ensure that
     child processes that also use ‘multiprocessing’ to spawn more
     children will recognize that they are in a virtual environment.

   - gh-98414(2): Fix ‘py.exe’ launcher handling of ‘-V:<COMPANY>/’
     option when default preferences have been set in environment
     variables or configuration files.

   - gh-97728(3): Fix possible crashes caused by the use of
     uninitialized variables when pass invalid arguments in *note
     os.system(): 14ac. on Windows and in Windows-specific modules (like
     ‘winreg’).

   - gh-90989(4): Made *note Python Launcher for Windows: 5c1. install
     per-user by default (unless an all users install already exists),
     and clarify some text in the installer.

   - gh-97649(5): The ‘Tools’ directory is no longer installed on
     Windows

   - gh-96965(6): Update libffi to 3.4.3

   - gh-96577(7): Fixes a potential buffer overrun in ‘msilib’.

   - gh-96559(8): Fixes the Windows launcher not using the compatible
     interpretation of default tags found in configuration files when no
     tag was passed to the command.

   - gh-94781(9): Fix ‘pcbuild.proj’ to clean previous instances of
     output files in ‘Python\deepfreeze’ and ‘Python\frozen_modules’
     directories on Windows.  Patch by Charlie Zhao.

   - gh-89545(10): Updates *note platform: aa. code getting the Windows
     version to use native Windows Management Instrumentation (WMI)
     queries to determine OS version, type, and architecture.

   - gh-95733(11): Make certain requirements of the Windows Store
     package optional to allow installing on earlier updates of Windows.

   - gh-95656(12): Enable the *note enable_load_extension(): 844. *note
     sqlite3: cf. API.

   - gh-95587(13): Fixes some issues where the Windows installer would
     incorrectly detect certain features of an existing install when
     upgrading.

   - gh-94399(14): Restores the behaviour of *note Python Launcher for
     Windows: 5c1. for ‘/usr/bin/env’ shebang lines, which will now
     search ‘PATH’ for an executable matching the given command.  If
     none is found, the usual search process is used.

   - gh-95445(15): Fixes the unsuccessful removal of the HTML document
     directory when uninstalling with Windows msi.

   - gh-95359(16): Fix *note Python Launcher for Windows: 5c1. handling
     of ‘py.ini’ commands (it was incorrectly expecting a ‘py_’ prefix
     on keys) and crashes when reading per-user configuration file.

   - gh-95285(17): Fix *note Python Launcher for Windows: 5c1. handling
     of command lines where it is only passed a short executable name.

   - gh-90844(18): Allow virtual environments to correctly launch when
     they have spaces in the path.

   - gh-94772(19): Fix incorrect handling of shebang lines in py.exe
     launcher

   - gh-94018(20): *note zipfile: 131. will now remove trailing spaces
     from path components when extracting files on Windows.

   - gh-93824(21): Drag and drop of files onto Python files in Windows
     Explorer has been enabled for Windows ARM64.

   - gh-43414(22): *note os.get_terminal_size(): 1146. now attempts to
     read the size from any provided handle, rather than only supporting
     file descriptors 0, 1 and 2.

   - gh-92817(23): Ensures that ‘py.exe’ will prefer an active virtual
     environment over default tags specified with environment variables
     or through a ‘py.ini’ file.

   - gh-92984(24): Explicitly disable incremental linking for non-Debug
     builds

   - gh-92841(25): *note asyncio: a. no longer throws ‘RuntimeError:
     Event loop is closed’ on interpreter exit after asynchronous socket
     activity.  Patch by Oleg Iarygin.

   - bpo-46907(26): Update Windows installer to use SQLite 3.38.4.

   - gh-91061(27): Accept os.PathLike for the argument to
     winsound.PlaySound

   - bpo-42658(28): Support native Windows case-insensitive path
     comparisons by using ‘LCMapStringEx’ instead of *note str.lower():
     191c. in ‘ntpath.normcase()’.  Add ‘LCMapStringEx’ to the ‘_winapi’
     module.

   - bpo-38704(29): Prevent installation on unsupported Windows
     versions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98360

   (2) https://github.com/python/cpython/issues/98414

   (3) https://github.com/python/cpython/issues/97728

   (4) https://github.com/python/cpython/issues/90989

   (5) https://github.com/python/cpython/issues/97649

   (6) https://github.com/python/cpython/issues/96965

   (7) https://github.com/python/cpython/issues/96577

   (8) https://github.com/python/cpython/issues/96559

   (9) https://github.com/python/cpython/issues/94781

   (10) https://github.com/python/cpython/issues/89545

   (11) https://github.com/python/cpython/issues/95733

   (12) https://github.com/python/cpython/issues/95656

   (13) https://github.com/python/cpython/issues/95587

   (14) https://github.com/python/cpython/issues/94399

   (15) https://github.com/python/cpython/issues/95445

   (16) https://github.com/python/cpython/issues/95359

   (17) https://github.com/python/cpython/issues/95285

   (18) https://github.com/python/cpython/issues/90844

   (19) https://github.com/python/cpython/issues/94772

   (20) https://github.com/python/cpython/issues/94018

   (21) https://github.com/python/cpython/issues/93824

   (22) https://github.com/python/cpython/issues/43414

   (23) https://github.com/python/cpython/issues/92817

   (24) https://github.com/python/cpython/issues/92984

   (25) https://github.com/python/cpython/issues/92841

   (26) https://bugs.python.org/issue?@action=redirect&bpo=46907

   (27) https://github.com/python/cpython/issues/91061

   (28) https://bugs.python.org/issue?@action=redirect&bpo=42658

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38704


File: python.info,  Node: macOS<20>,  Next: IDLE<19>,  Prev: Windows<27>,  Up: Python 3 12 0 alpha 1

1.23.35.26 macOS
................

   - gh-97897(1): The macOS 13 SDK includes support for the ‘mkfifoat’
     and ‘mknodat’ system calls.  Using the ‘dir_fd’ option with either
     *note os.mkfifo(): dbe. or *note os.mknod(): dbf. could result in a
     segfault if cpython is built with the macOS 13 SDK but run on an
     earlier version of macOS. Prevent this by adding runtime support
     for detection of these system calls (“weaklinking”) as is done for
     other newer syscalls on macOS.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97897


File: python.info,  Node: IDLE<19>,  Next: Tools/Demos<17>,  Prev: macOS<20>,  Up: Python 3 12 0 alpha 1

1.23.35.27 IDLE
...............

   - gh-97527(1): Fix a bug in the previous bugfix that caused IDLE to
     not start when run with 3.10.8, 3.12.0a1, and at least Microsoft
     Python 3.10.2288.0 installed without the Lib/test package.  3.11.0
     was never affected.

   - gh-65802(2): Document handling of extensions in Save As dialogs.

   - gh-95191(3): Include prompts when saving Shell (interactive input
     and output).

   - gh-95511(4): Fix the Shell context menu copy-with-prompts bug of
     copying an extra line when one selects whole lines.

   - gh-95471(5): In the Edit menu, move ‘Select All’ and add a new
     separator.

   - gh-95411(6): Enable using IDLE’s module browser with .pyw files.

   - gh-89610(7): Add .pyi as a recognized extension for IDLE on macOS.
     This allows opening stub files by double clicking on them in the
     Finder.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97527

   (2) https://github.com/python/cpython/issues/65802

   (3) https://github.com/python/cpython/issues/95191

   (4) https://github.com/python/cpython/issues/95511

   (5) https://github.com/python/cpython/issues/95471

   (6) https://github.com/python/cpython/issues/95411

   (7) https://github.com/python/cpython/issues/89610


File: python.info,  Node: Tools/Demos<17>,  Next: C API<28>,  Prev: IDLE<19>,  Up: Python 3 12 0 alpha 1

1.23.35.28 Tools/Demos
......................

   - gh-68686(1): Remove ptags and eptags scripts.

   - gh-97681(2): Remove the ‘Tools/demo/’ directory which contained old
     demo scripts.  A copy can be found in the old-demos project(3).
     Patch by Victor Stinner.

   - gh-97669(4): Remove outdated example scripts of the
     ‘Tools/scripts/’ directory.  A copy can be found in the old-demos
     project(5).  Patch by Victor Stinner.

   - gh-95853(6): The ‘wasm_build.py’ script now pre-builds Emscripten
     ports, checks for broken EMSDK versions, and warns about pkg-config
     env vars.

   - gh-95853(7): The new tool ‘Tools/wasm/wasm_builder.py’ automates
     configure, compile, and test steps for building CPython on
     WebAssembly platforms.

   - gh-95731(8): Fix handling of module docstrings in
     ‘Tools/i18n/pygettext.py’.

   - gh-93939(9): Add script ‘Tools/scripts/check_modules.py’ to check
     and validate builtin and shared extension modules.  The script also
     handles ‘Modules/Setup’ and will eventually replace ‘setup.py’.

   - gh-94538(10): Fix Argument Clinic output to custom file
     destinations.  Patch by Erlend E. Aasland.

   - gh-94430(11): Allow parameters named ‘module’ and ‘self’ with
     custom C names in Argument Clinic.  Patch by Erlend E. Aasland

   - gh-86087(12): The ‘Tools/scripts/parseentities.py’ script used to
     parse HTML4 entities has been removed.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/68686

   (2) https://github.com/python/cpython/issues/97681

   (3) https://github.com/gvanrossum/old-demos

   (4) https://github.com/python/cpython/issues/97669

   (5) https://github.com/gvanrossum/old-demos

   (6) https://github.com/python/cpython/issues/95853

   (7) https://github.com/python/cpython/issues/95853

   (8) https://github.com/python/cpython/issues/95731

   (9) https://github.com/python/cpython/issues/93939

   (10) https://github.com/python/cpython/issues/94538

   (11) https://github.com/python/cpython/issues/94430

   (12) https://github.com/python/cpython/issues/86087


File: python.info,  Node: C API<28>,  Prev: Tools/Demos<17>,  Up: Python 3 12 0 alpha 1

1.23.35.29 C API
................

   - gh-98393(1): The *note PyUnicode_FSDecoder(): 57a. function no
     longer accepts bytes-like paths, like *note bytearray: 2ea. and
     *note memoryview: 2eb. types: only the exact *note bytes: 1c2. type
     is accepted for bytes strings.  Patch by Victor Stinner.

   - gh-91051(2): Add *note PyType_Watch(): 568. and related APIs to
     allow callbacks on *note PyType_Modified(): 1921.

   - gh-95756(3): Lazily create and cache ‘co_’ attributes for better
     performance for code getters.

   - gh-96512(4): Configuration for the *note integer string conversion
     length limitation: 5f8. now lives in the PyConfig C API struct.

   - gh-95589(5): Extensions classes that set ‘tp_dictoffset’ and
     ‘tp_weaklistoffset’ lose the support for multiple inheritance, but
     are now safe.  Extension classes should use *note
     Py_TPFLAGS_MANAGED_DICT: 36e. and *note Py_TPFLAGS_MANAGED_WEAKREF:
     55d. instead.

   - gh-95781(6): An unrecognized format character in *note
     PyUnicode_FromFormat(): 38d. and *note PyUnicode_FromFormatV():
     577. now sets a *note SystemError: 578.  In previous versions it
     caused all the rest of the format string to be copied as-is to the
     result string, and any extra arguments discarded.

   - gh-92678(7): Restore the 3.10 behavior for multiple inheritance of
     C extension classes that store their dictionary at the end of the
     struct.

   - gh-92678(8): Support C extensions using managed dictionaries by
     setting the ‘Py_TPFLAGS_MANAGED_DICT’ flag.

   - gh-93274(9): API for implementing vectorcall (*note
     Py_TPFLAGS_HAVE_VECTORCALL: 557, *note PyVectorcall_NARGS(): 558.
     and *note PyVectorcall_Call(): 559.) was added to the limited API
     and stable ABI.

   - gh-95504(10): Fix sign placement when specifying width or precision
     in *note PyUnicode_FromFormat(): 38d. and *note
     PyUnicode_FromFormatV(): 577.  Patch by Philip Georgi.

   - gh-93012(11): The *note Py_TPFLAGS_HAVE_VECTORCALL: 557. flag is
     now removed from a class when the class’s *note __call__(): 55b.
     method is reassigned.  This makes vectorcall safe to use with
     mutable types (i.e.  heap types without the ‘immutable’ flag).
     Mutable types that do not override *note tp_call: 55c. now inherit
     the ‘Py_TPFLAGS_HAVE_VECTORCALL’ flag.

   - gh-95388(12): Creating *note immutable types: 3c5. with mutable
     bases is deprecated and is planned to be disabled in Python 3.14.

   - gh-92678(13): Adds unstable C-API functions
     ‘_PyObject_VisitManagedDict’ and ‘_PyObject_ClearManagedDict’ to
     allow C extensions to allow the VM to manage their object’s
     dictionaries.

   - gh-94936(14): Added *note PyCode_GetVarnames(): 77c, *note
     PyCode_GetCellvars(): 77d. and *note PyCode_GetFreevars(): 77e. for
     accessing ‘co_varnames’, ‘co_cellvars’ and ‘co_freevars’
     respectively via the C API.

   - gh-94930(15): Fix ‘SystemError’ raised when *note
     PyArg_ParseTupleAndKeywords(): 386. is used with ‘#’ in ‘(...)’ but
     without ‘PY_SSIZE_T_CLEAN’ defined.

   - gh-94731(16): Python again uses C-style casts for most casting
     operations when compiled with C++.  This may trigger compiler
     warnings, if they are enabled with e.g.  ‘-Wold-style-cast’ or
     ‘-Wzero-as-null-pointer-constant’ options for ‘g++’.

   - gh-93937(17): The following frame functions and type are now
     directly available with ‘#include <Python.h>’, it’s no longer
     needed to add ‘#include <frameobject.h>’:

        * *note PyFrame_Check(): 788.

        * *note PyFrame_GetBack(): 789.

        * *note PyFrame_GetBuiltins(): 76e.

        * *note PyFrame_GetGenerator(): 76f.

        * *note PyFrame_GetGlobals(): 770.

        * *note PyFrame_GetLasti(): 771.

        * *note PyFrame_GetLocals(): 422.

        * *note PyFrame_Type: 78a.

     Patch by Victor Stinner.

   - gh-91321(18): Fix the compatibility of the Python C API with C++
     older than C++11.  Patch by Victor Stinner.

   - gh-91731(19): Avoid defining the ‘static_assert’ when compiling
     with C++ 11, where this is a keyword and redefining it can lead to
     undefined behavior.  Patch by Pablo Galindo

   - gh-89546(20): *note PyType_FromMetaclass(): 553. (and other
     ‘PyType_From*’ functions) now check that offsets and the base
     class’s *note tp_basicsize: 991. fit in the new class’s
     ‘tp_basicsize’.

   - gh-93503(21): Add two new public functions to the public C-API,
     *note PyEval_SetProfileAllThreads(): 562. and *note
     PyEval_SetTraceAllThreads(): 425, that allow to set tracing and
     profiling functions in all running threads in addition to the
     calling one.  Also, two analogous functions to the *note threading:
     ed. module (*note threading.setprofile_all_threads(): 4cc. and
     *note threading.settrace_all_threads(): 4cb.) that allow to do the
     same from Python.  Patch by Pablo Galindo

   - gh-93442(22): Add C++ overloads for _Py_CAST_impl() to handle
     0/NULL. This will allow C++ extensions that pass 0 or NULL to
     macros using _Py_CAST() to continue to compile.

   - gh-93466(23): Slot IDs in PyType_Spec may not be repeated.  The
     documentation was updated to mention this.  For some cases of
     repeated slots, PyType_FromSpec and related functions will now
     raise an exception.

   - gh-92898(24): Fix C++ compiler warnings when casting function
     arguments to ‘PyObject*’.  Patch by Serge Guelton.

   - gh-93103(25): Deprecate global configuration variables, like *note
     Py_IgnoreEnvironmentFlag: 3db, in the documentation: the *note
     Py_InitializeFromConfig(): 3c8. API should be instead.  Patch by
     Victor Stinner.

   - gh-77782(26): Deprecate global configuration variable like *note
     Py_IgnoreEnvironmentFlag: 3db.: the *note
     Py_InitializeFromConfig(): 3c8. API should be instead.  Patch by
     Victor Stinner.

   - gh-92913(27): Ensures changes to *note
     PyConfig.module_search_paths: 3a5. are ignored unless *note
     PyConfig.module_search_paths_set: 5f2. is set

   - gh-92781(28): Avoid mixing declarations and code in the C API to
     fix the compiler warning: “ISO C90 forbids mixed declarations and
     code” [-Werror=declaration-after-statement].  Patch by Victor
     Stinner.

   - gh-92651(29): Remove the ‘token.h’ header file.  There was never
     any public tokenizer C API. The ‘token.h’ header file was only
     designed to be used by Python internals.  Patch by Victor Stinner.

   - gh-92536(30): Remove legacy Unicode APIs based on ‘Py_UNICODE*’.

   - gh-85858(31): Remove the ‘PyUnicode_InternImmortal()’ function and
     the ‘SSTATE_INTERNED_IMMORTAL’ macro.  Patch by Victor Stinner.

   - gh-92193(32): Add new function *note PyFunction_SetVectorcall():
     563. to the C API which sets the vectorcall field of a given *note
     PyFunctionObject: 564.

     Warning: extensions using this API must preserve the behavior of
     the unaltered function!

   - gh-59121(33): Fixed an assert that prevented ‘PyRun_InteractiveOne’
     from providing tracebacks when parsing from the provided FD.

   - bpo-45383(34): The *note PyType_FromSpec(): 580. API will now find
     and use a metaclass based on the provided bases.  An error will be
     raised if there is a metaclass conflict.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/98393

   (2) https://github.com/python/cpython/issues/91051

   (3) https://github.com/python/cpython/issues/95756

   (4) https://github.com/python/cpython/issues/96512

   (5) https://github.com/python/cpython/issues/95589

   (6) https://github.com/python/cpython/issues/95781

   (7) https://github.com/python/cpython/issues/92678

   (8) https://github.com/python/cpython/issues/92678

   (9) https://github.com/python/cpython/issues/93274

   (10) https://github.com/python/cpython/issues/95504

   (11) https://github.com/python/cpython/issues/93012

   (12) https://github.com/python/cpython/issues/95388

   (13) https://github.com/python/cpython/issues/92678

   (14) https://github.com/python/cpython/issues/94936

   (15) https://github.com/python/cpython/issues/94930

   (16) https://github.com/python/cpython/issues/94731

   (17) https://github.com/python/cpython/issues/93937

   (18) https://github.com/python/cpython/issues/91321

   (19) https://github.com/python/cpython/issues/91731

   (20) https://github.com/python/cpython/issues/89546

   (21) https://github.com/python/cpython/issues/93503

   (22) https://github.com/python/cpython/issues/93442

   (23) https://github.com/python/cpython/issues/93466

   (24) https://github.com/python/cpython/issues/92898

   (25) https://github.com/python/cpython/issues/93103

   (26) https://github.com/python/cpython/issues/77782

   (27) https://github.com/python/cpython/issues/92913

   (28) https://github.com/python/cpython/issues/92781

   (29) https://github.com/python/cpython/issues/92651

   (30) https://github.com/python/cpython/issues/92536

   (31) https://github.com/python/cpython/issues/85858

   (32) https://github.com/python/cpython/issues/92193

   (33) https://github.com/python/cpython/issues/59121

   (34) https://bugs.python.org/issue?@action=redirect&bpo=45383


File: python.info,  Node: Python 3 11 0 beta 1,  Next: Python 3 11 0 alpha 7,  Prev: Python 3 12 0 alpha 1,  Up: Changelog

1.23.36 Python 3.11.0 beta 1
----------------------------

'Release date: 2022-05-06'

* Menu:

* Security: Security<25>.
* Core and Builtins: Core and Builtins<61>.
* Library: Library<64>.
* Core and Builtins: Core and Builtins<62>.
* Build: Build<32>.
* Core and Builtins: Core and Builtins<63>.
* Library: Library<65>.
* Documentation: Documentation<27>.
* Tests: Tests<30>.
* Build: Build<33>.
* Windows: Windows<28>.
* macOS: macOS<21>.
* Tools/Demos: Tools/Demos<18>.
* C API: C API<29>.


File: python.info,  Node: Security<25>,  Next: Core and Builtins<61>,  Up: Python 3 11 0 beta 1

1.23.36.1 Security
..................

   - gh-57684(1): Add the *note -P: 5a7. command line option and the
     *note PYTHONSAFEPATH: 5a8. environment variable to not prepend a
     potentially unsafe path to *note sys.path: 3b7.  Patch by Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/57684


File: python.info,  Node: Core and Builtins<61>,  Next: Library<64>,  Prev: Security<25>,  Up: Python 3 11 0 beta 1

1.23.36.2 Core and Builtins
...........................

   - gh-89519(1): Chaining classmethod descriptors (introduced in
     bpo-19072(2)) is deprecated.  It can no longer be used to wrap
     other descriptors such as property().  The core design of this
     feature was flawed, and it caused a number of downstream problems.

   - gh-92345(3): ‘pymain_run_python()’ now imports ‘readline’ and
     ‘rlcompleter’ before sys.path is extended to include the current
     working directory of an interactive interpreter.  Non-interactive
     interpreters are not affected.

   - bpo-43857(4): Improve the *note AttributeError: 34e. message when
     deleting a missing attribute.  Patch by Géry Ogam.

   - gh-92245(5): Make sure that PEP 523 is respected in all cases.  In
     3.11a7, specialization may have prevented Python-to-Python calls
     respecting PEP 523.

   - gh-92203(6): Add a closure keyword-only parameter to *note exec():
     17f.  It can only be specified when exec-ing a code object that
     uses free variables.  When specified, it must be a tuple, with
     exactly the number of cell variables referenced by the code object.
     closure has a default value of ‘None’, and it must be ‘None’ if the
     code object doesn’t refer to any free variables.

   - gh-91173(7): Disable frozen modules in debug builds.  Patch by
     Kumar Aditya.

   - gh-92114(8): Improve error message when subscript a type with
     ‘__class_getitem__’ set to ‘None’.

   - gh-92112(9): Fix crash triggered by an evil custom ‘mro()’ on a
     metaclass.

   - gh-92063(10): The ‘PRECALL_METHOD_DESCRIPTOR_FAST_WITH_KEYWORDS’
     instruction now ensures methods are called only on objects of the
     correct type.

   - gh-92031(11): Deoptimize statically allocated code objects during
     ‘Py_FINALIZE()’ so that future ‘_PyCode_Quicken’ calls always start
     with unquickened code.

   - gh-92036(12): Fix a crash in subinterpreters related to the garbage
     collector.  When a subinterpreter is deleted, untrack all objects
     tracked by its GC. To prevent a crash in deallocator functions
     expecting objects to be tracked by the GC, leak a strong reference
     to these objects on purpose, so they are never deleted and their
     deallocator functions are not called.  Patch by Victor Stinner.

   - gh-92032(13): The interpreter can now autocomplete soft keywords,
     as of now ‘match’, ‘case’, and ‘_’ (wildcard pattern) from PEP
     634(14).

   - gh-87999(15): The warning emitted by the Python parser for a
     numeric literal immediately followed by keyword has been changed
     from deprecation warning to syntax warning.

   - gh-91869(16): Fix an issue where specialized opcodes with extended
     arguments could produce incorrect tracing output or lead to
     assertion failures.

   - gh-91603(17): Speed up *note types.UnionType: 63d. instantiation.
     Based on patch provided by Yurii Karabas.

   - gh-89373(18): If Python is built in debug mode, Python now ensures
     that deallocator functions leave the current exception unchanged.
     Patch by Victor Stinner.

   - gh-91632(19): Fix a minor memory leak at exit: release the memory
     of the ‘generic_alias_iterator’ type.  Patch by Donghee Na.

   - gh-81548(20): Octal escapes with value larger than ‘0o377’ now
     produce a *note DeprecationWarning: 1a5.  In a future Python
     version they will be a *note SyntaxWarning: 469. and eventually a
     *note SyntaxError: 18d.

   - bpo-43950(21): Use a single compact table for line starts, ends and
     column offsets.  Reduces memory consumption for location info by
     half

   - gh-91102(22): Use Argument Clinic for ‘EncodingMap’.  Patch by Oleg
     Iarygin.

   - gh-91636(23): Fixed a crash in a garbage-collection edge-case, in
     which a ‘PyFunction_Type.tp_clear’ function could leave a python
     function object in an inconsistent state.

   - gh-91603(24): Speed up *note isinstance(): 445. and *note
     issubclass(): 7c5. checks for *note types.UnionType: 63d.  Patch by
     Yurii Karabas.

   - gh-91625(25): Fixed a bug in which adaptive opcodes ignored any
     preceding ‘EXTENDED_ARG’s on specialization failure.

   - gh-78607(26): The LLTRACE special build now looks for the name
     ‘__lltrace__’ defined in module globals, rather than the name
     ‘__ltrace__’, which had been introduced as a typo.

   - gh-91576(27): Speed up iteration of ascii strings by 50%.  Patch by
     Kumar Aditya.

   - gh-89279(28): Improve interpreter performance on Windows by
     inlining a few specific macros.

   - gh-91502(29): Add a new ‘_PyFrame_IsEntryFrame()’ API function, to
     check if a *note PyFrameObject: 78c. is an entry frame.  Patch by
     Pablo Galindo.

   - gh-91266(30): Refactor the ‘bytearray’ strip methods ‘strip’,
     ‘lstrip’ and ‘rstrip’ to use a common implementation.

   - gh-91479(31): Replaced the ‘__note__’ field of *note BaseException:
     5be. (added in an earlier version of 3.11) with the final design of
     PEP 678(32).  Namely, ‘BaseException’ gets an ‘add_note()’ method,
     and its ‘__notes__’ field is created when necessary.

   - gh-46055(33): Speed up right shift of negative integers, by
     removing unnecessary creation of temporaries.  Original patch by
     Xinhang Xu, reworked by Mark Dickinson.

   - gh-91462(34): Make the interpreter’s low-level tracing (lltrace)
     feature output more readable by displaying opcode names (rather
     than just numbers), and by displaying stack contents before each
     opcode.

   - gh-89455(35): Fixed an uninitialized bool value in the traceback
     printing code path that was introduced by the initial bpo-45292(36)
     exception groups work.

   - gh-91421(37): Fix a potential integer overflow in _Py_DecodeUTF8Ex.

   - gh-91428(38): Add ‘static const char *const _PyOpcode_OpName[256] =
     {...};’ to ‘opcode.h’ for debug builds to assist in debugging the
     Python interpreter.  It is now more convenient to make various
     forms of debugging output more human-readable by including opcode
     names rather than just the corresponding decimal digits.

   - bpo-47120(39): Make *note POP_JUMP_IF_TRUE: 17fe, *note
     POP_JUMP_IF_FALSE: 17ff, *note POP_JUMP_IF_NONE: 1925. and *note
     POP_JUMP_IF_NOT_NONE: 1926. virtual, mapping to new relative jump
     opcodes.

   - bpo-45317(40): Add internal documentation explaining design of new
     (for 3.11) frame stack.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89519

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19072

   (3) https://github.com/python/cpython/issues/92345

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43857

   (5) https://github.com/python/cpython/issues/92245

   (6) https://github.com/python/cpython/issues/92203

   (7) https://github.com/python/cpython/issues/91173

   (8) https://github.com/python/cpython/issues/92114

   (9) https://github.com/python/cpython/issues/92112

   (10) https://github.com/python/cpython/issues/92063

   (11) https://github.com/python/cpython/issues/92031

   (12) https://github.com/python/cpython/issues/92036

   (13) https://github.com/python/cpython/issues/92032

   (14) https://peps.python.org/pep-0634/

   (15) https://github.com/python/cpython/issues/87999

   (16) https://github.com/python/cpython/issues/91869

   (17) https://github.com/python/cpython/issues/91603

   (18) https://github.com/python/cpython/issues/89373

   (19) https://github.com/python/cpython/issues/91632

   (20) https://github.com/python/cpython/issues/81548

   (21) https://bugs.python.org/issue?@action=redirect&bpo=43950

   (22) https://github.com/python/cpython/issues/91102

   (23) https://github.com/python/cpython/issues/91636

   (24) https://github.com/python/cpython/issues/91603

   (25) https://github.com/python/cpython/issues/91625

   (26) https://github.com/python/cpython/issues/78607

   (27) https://github.com/python/cpython/issues/91576

   (28) https://github.com/python/cpython/issues/89279

   (29) https://github.com/python/cpython/issues/91502

   (30) https://github.com/python/cpython/issues/91266

   (31) https://github.com/python/cpython/issues/91479

   (32) https://peps.python.org/pep-0678/

   (33) https://github.com/python/cpython/issues/46055

   (34) https://github.com/python/cpython/issues/91462

   (35) https://github.com/python/cpython/issues/89455

   (36) https://bugs.python.org/issue?@action=redirect&bpo=45292

   (37) https://github.com/python/cpython/issues/91421

   (38) https://github.com/python/cpython/issues/91428

   (39) https://bugs.python.org/issue?@action=redirect&bpo=47120

   (40) https://bugs.python.org/issue?@action=redirect&bpo=45317


File: python.info,  Node: Library<64>,  Next: Core and Builtins<62>,  Prev: Core and Builtins<61>,  Up: Python 3 11 0 beta 1

1.23.36.3 Library
.................

   - bpo-47197(1): ctypes used to mishandle ‘void’ return types, so that
     for instance a function declared like ‘ctypes.CFUNCTYPE(None,
     ctypes.c_int)’ would be called with signature ‘int f(int)’ instead
     of ‘void f(int)’.  Wasm targets require function pointers to be
     called with the correct signatures so this led to crashes.  The
     problem is now fixed.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47197


File: python.info,  Node: Core and Builtins<62>,  Next: Build<32>,  Prev: Library<64>,  Up: Python 3 11 0 beta 1

1.23.36.4 Core and Builtins
...........................

   - bpo-47120(1): Make opcodes ‘JUMP_IF_TRUE_OR_POP’ and
     ‘JUMP_IF_FALSE_OR_POP’ relative rather than absolute.

   - bpo-47177(2): Replace the ‘f_lasti’ member of the internal
     ‘_PyInterpreterFrame’ structure with a ‘prev_instr’ pointer, which
     reduces overhead in the main interpreter loop.  The ‘f_lasti’
     attribute of Python-layer frame objects is preserved for
     backward-compatibility.

   - bpo-46961(3): Integer mod/remainder operations, including the
     three-argument form of *note pow(): 9dd, now consistently return
     ints from the global small integer cache when applicable.

   - bpo-46962(4): Classes and functions that unconditionally declared
     their docstrings ignoring the ‘--without-doc-strings’ compilation
     flag no longer do so.

     The classes affected are ‘ctypes.UnionType’, *note
     pickle.PickleBuffer: 15c6, ‘testcapi.RecursingInfinitelyError’, and
     *note types.GenericAlias: 7f0.

     The functions affected are 24 methods in *note ctypes: 2a.

     Patch by Oleg Iarygin.

   - bpo-46942(5): Use Argument Clinic for the *note types.MethodType:
     1929. constructor.  Patch by Oleg Iarygin.

   - bpo-46764(6): Fix wrapping bound methods with @classmethod

   - bpo-43464(7): Optimize *note set.intersection(): 192a. for non-set
     arguments.

   - bpo-46721(8): Optimize *note set.issuperset(): 192b. for non-set
     argument.

   - bpo-46509(9): Add type-specialized versions of the ‘Py_DECREF()’,
     and use them for ‘float’, ‘int’, ‘str’, ‘bool’, and ‘None’ to avoid
     pointer-chasing at runtime where types are known at C compile time.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47120

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47177

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46961

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46962

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46942

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46764

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43464

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46721

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46509


File: python.info,  Node: Build<32>,  Next: Core and Builtins<63>,  Prev: Core and Builtins<62>,  Up: Python 3 11 0 beta 1

1.23.36.5 Build
...............

   - bpo-46045(1): Do not use POSIX semaphores on NetBSD

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46045


File: python.info,  Node: Core and Builtins<63>,  Next: Library<65>,  Prev: Build<32>,  Up: Python 3 11 0 beta 1

1.23.36.6 Core and Builtins
...........................

   - bpo-36819(1): Fix crashes in built-in encoders with error handlers
     that return position less or equal than the starting position of
     non-encodable characters.

   - bpo-34093(2): ‘marshal.dumps()’ uses ‘FLAG_REF’ for all interned
     strings.  This makes output more deterministic and helps
     reproducible build.

   - bpo-26579(3): Added ‘object.__getstate__’ which provides the
     default implementation of the ‘__getstate__()’ method.

     Copying and pickling instances of subclasses of builtin types
     bytearray, set, frozenset, collections.OrderedDict,
     collections.deque, weakref.WeakSet, and datetime.tzinfo now copies
     and pickles instance attributes implemented as slots.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36819

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34093

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26579


File: python.info,  Node: Library<65>,  Next: Documentation<27>,  Prev: Core and Builtins<63>,  Up: Python 3 11 0 beta 1

1.23.36.7 Library
.................

   - gh-87901(1): Add the 'encoding' parameter to *note os.popen(): a96.

   - gh-90997(2): Fix an issue where *note dis: 38. utilities may
     interpret populated inline cache entries as valid instructions.

   - gh-92332(3): Deprecate *note typing.Text: 30b. (removal of the
     class is currently not planned).  Patch by Alex Waygood.

   - gh-78157(4): Deprecate nested classes in enum definitions becoming
     members – in 3.13 they will be normal classes; add ‘member’ and
     ‘nonmember’ functions to allow control over results now.

   - gh-92356(5): Fixed a performance regression in ctypes function
     calls.

   - gh-90997(6): Show the actual named values stored in inline caches
     when ‘show_caches=True’ is passed to *note dis: 38. utilities.

   - gh-92301(7): Prefer ‘close_range()’ to iterating over procfs for
     file descriptor closing in *note subprocess: d6. for better
     performance.

   - gh-67248(8): Sort the miscellaneous topics in Cmd.do_help()

   - gh-92210(9): Port ‘socket.__init__’ to Argument Clinic.  Patch by
     Cinder.

   - gh-80010(10): Add support for generalized ISO 8601 parsing to *note
     datetime.datetime.fromisoformat(): 61a, *note
     datetime.date.fromisoformat(): 618. and *note
     datetime.time.fromisoformat(): 619.  Patch by Paul Ganssle.

   - gh-92118(11): Fix a 3.11 regression in *note contextmanager():
     1247, which caused it to propagate exceptions with incorrect
     tracebacks.

   - gh-90887(12): Adding ‘COPYFILE_STAT’, ‘COPYFILE_ACL’ and
     ‘COPYFILE_XATTR’ constants for ‘os.fcopyfile()’ available in macOs.

   - gh-91215(13): For *note @~dataclasses.dataclass: 1cb, add
     'weakref_slot'.  The new parameter defaults to ‘False’.  If true,
     and if ‘slots=True’, add a slot named ‘"__weakref__"’, which will
     allow instances to be weakref’d.  Contributed by Eric V. Smith

   - gh-85984(14): New function os.login_tty() for Unix.

   - gh-92128(15): Add *note __class_getitem__(): 73e. to *note
     logging.LoggerAdapter: 133e. and *note logging.StreamHandler: 123d,
     allowing them to be parameterized at runtime.  Patch by Alex
     Waygood.

   - gh-92049(16): Forbid pickling constants ‘re._constants.SUCCESS’
     etc.  Previously, pickling did not fail, but the result could not
     be unpickled.

   - gh-92062(17): *note inspect.Parameter: 1d0. now raises *note
     ValueError: 202. if ‘name’ is a keyword, in addition to the
     existing check that it is an identifier.

   - gh-87390(18): Add an ‘__unpacked__’ attribute to *note
     types.GenericAlias: 7f0.  Patch by Jelle Zijlstra.

   - gh-88089(19): Add support for generic *note typing.NamedTuple: 2b0.

   - gh-91996(20): New http.HTTPMethod enum to represent all the
     available HTTP request methods in a convenient way

   - gh-91984(21): Modified test strings in test_argparse.py to not
     contain trailing spaces before end of line.

   - gh-91952(22): Add ‘encoding="locale"’ support to
     ‘TextIOWrapper.reconfigure()’.

   - gh-91954(23): Add 'encoding' and 'errors' arguments to *note
     subprocess.getoutput(): ffc. and *note
     subprocess.getstatusoutput(): ffd.

   - bpo-47029(24): Always close the read end of the pipe used by *note
     multiprocessing.Queue: 192f. 'after' the last write of buffered
     data to the write end of the pipe to avoid *note BrokenPipeError:
     109a. at garbage collection and at *note
     multiprocessing.Queue.close(): 1930. calls.  Patch by Géry Ogam.

   - gh-91928(25): Add ‘datetime.UTC’ alias for ‘datetime.timezone.utc’.

     Patch by Kabir Kwatra.

   - gh-68966(26): The ‘mailcap’ module is now deprecated and will be
     removed in Python 3.13.  See PEP 594(27) for the rationale and the
     *note mimetypes: 8f. module for an alternative.  Patch by Victor
     Stinner.

   - gh-91401(28): Provide a way to disable *note subprocess: d6. use of
     ‘vfork()’ just in case it is ever needed and document the existing
     mechanism for ‘posix_spawn()’.

   - gh-64783(29): Fix *note signal.NSIG: 1931. value on FreeBSD to
     accept signal numbers greater than 32, like ‘signal.SIGRTMIN’ and
     ‘signal.SIGRTMAX’.  Patch by Victor Stinner.

   - gh-91910(30): Add missing f prefix to f-strings in error messages
     from the *note multiprocessing: 94. and *note asyncio: a. modules.

   - gh-91860(31): Add *note typing.dataclass_transform(): 4d7,
     implementing PEP 681(32).  Patch by Jelle Zijlstra.

   - gh-91832(33): Add ‘required’ attribute to *note argparse.Action:
     1932. repr output.

   - gh-91827(34): In the *note tkinter: f0. module add method
     ‘info_patchlevel()’ which returns the exact version of the Tcl
     library as a named tuple similar to *note sys.version_info: 6a3.

   - gh-84461(35): Add *note -enable-wasm-pthreads: 1933. to enable
     pthreads support for WASM builds.  ‘Emscripten/node’ no longer has
     threading enabled by default.  Include additional file systems.

   - gh-91821(36): Fix unstable ‘test_from_tuple’ test in
     ‘test_decimal.py’.

   - gh-91217(37): Deprecate the xdrlib module.

   - gh-91217(38): Deprecate the uu module.

   - gh-91760(39): More strict rules will be applied for numerical group
     references and group names in regular expressions.  For now, a
     deprecation warning is emitted for group references and group names
     which will be errors in future Python versions.

   - gh-84461(40): Add provisional *note sys._emscripten_info: 1934.
     named tuple with build-time and run-time information about
     Emscripten platform.

   - gh-90623(41): *note signal.raise_signal(): 1935. and *note
     os.kill(): 13b4. now check immediately for pending signals.  Patch
     by Victor Stinner.

   - gh-91734(42): Fix OSS audio support on Solaris.

   - gh-90633(43): Include the passed value in the exception thrown by
     *note typing.assert_never(): 6aa.  Patch by Jelle Zijlstra.

   - gh-91700(44): Compilation of regular expression containing a
     conditional expression ‘(?(group)...)’ now raises an appropriate
     ‘re.error’ if the group number refers to not defined group.
     Previously an internal RuntimeError was raised.

   - gh-91231(45): Add an optional keyword 'shutdown_timeout' parameter
     to the ‘multiprocessing.BaseManager’ constructor.  Kill the process
     if terminate() takes longer than the timeout.  Patch by Victor
     Stinner.

   - gh-91621(46): Fix *note typing.get_type_hints(): 6b4. for *note
     collections.abc.Callable: 7ef.  Patch by Shantanu Jain.

   - gh-90568(47): Parsing ‘\N’ escapes of Unicode Named Character
     Sequences in a *note regular expression: b9. raises now ‘re.error’
     instead of ‘TypeError’.

   - gh-91670(48): Remove deprecated ‘SO’ config variable in *note
     sysconfig: db.

   - gh-91217(49): Deprecate the telnetlib module.

   - gh-91217(50): Deprecate the sunau module.

   - gh-91217(51): Deprecate the spwd module.

   - gh-91217(52): Deprecate the sndhdr module, as well as inline needed
     functionality for ‘email.mime.MIMEAudio’.

   - gh-91616(53): *note re: b9. module, fix *note fullmatch(): fbf.
     mismatch when using Atomic Grouping or Possessive Quantifiers.

   - gh-91217(54): Deprecate the ‘pipes’ module.

   - gh-91217(55): Deprecate the ossaudiodev module.

   - bpo-47256(56): *note re: b9. module, limit the maximum capturing
     group to 1,073,741,823 in 64-bit build, this increases the depth of
     backtracking.

   - gh-91217(57): Deprecate the nis module.

   - gh-91595(58): Fix the comparison of character and integer inside
     ‘Tools.gdb.libpython.write_repr()’.  Patch by Yu Liu.

   - gh-74166(59): Add option to raise all errors from *note
     create_connection(): 675. in an *note ExceptionGroup: 1b6. when it
     fails to create a connection.  The default remains to raise only
     the last error that had occurred when multiple addresses were
     tried.

   - gh-91487(60): Optimize asyncio UDP speed, over 100 times faster
     when transferring a large file.

   - gh-91575(61): Update case-insensitive matching in the *note re: b9.
     module to the latest Unicode version.

   - gh-90622(62): In ‘concurrent.futures.process.ProcessPoolExecutor’
     disallow the “fork” multiprocessing start method when the new
     ‘max_tasks_per_child’ feature is used as the mix of threads+fork
     can hang the child processes.  Default to using the safe “spawn”
     start method in that circumstance if no ‘mp_context’ was supplied.

   - gh-89022(63): In *note sqlite3: cf, ‘SQLITE_MISUSE’ result codes
     are now mapped to *note InterfaceError: 680. instead of *note
     ProgrammingError: 4f5.  Also, more accurate exceptions are raised
     when binding parameters fail.  Patch by Erlend E. Aasland.

   - gh-91526(64): Stop calling ‘os.device_encoding(file.fileno())’ in
     ‘TextIOWrapper’.  It was complex, never documented, and didn’t work
     for most cases.  (Patch by Inada Naoki.)

   - gh-88116(65): Change the frame-related functions in the *note
     inspect: 7e. module to return a regular object (that is backwards
     compatible with the old tuple-like interface) that include the
     extended PEP 657(66) position information (end line number, column
     and end column).  The affected functions are: *note
     inspect.getframeinfo(): 652, *note inspect.getouterframes(): 653,
     *note inspect.getinnerframes(): 654, *note inspect.stack(): 655.
     and *note inspect.trace(): 656.  Patch by Pablo Galindo.

   - gh-69093(67): Add indexing and slicing support to *note
     sqlite3.Blob: 685.  Patch by Aviv Palivoda and Erlend E. Aasland.

   - gh-69093(68): Add *note context manager: 5d7. support to *note
     sqlite3.Blob: 685.  Patch by Aviv Palivoda and Erlend E. Aasland.

   - gh-91217(69): Deprecate nntplib.

   - gh-91217(70): Deprecate msilib.

   - gh-91404(71): Improve the performance of *note re: b9. matching by
     using computed gotos (or “threaded code”) on supported platforms
     and removing expensive pointer indirections.

   - gh-91217(72): Deprecate the imghdr module.

   - gh-91217(73): Deprecate the crypt module.

   - gh-91276(74): Make space for longer opcodes in *note dis: 38.
     output.

   - bpo-47000(75): Make ‘TextIOWrapper’ uses locale encoding when
     ‘encoding="locale"’ is specified even in UTF-8 mode.

   - gh-91230(76): *note warnings.catch_warnings(): 587. now accepts
     arguments for *note warnings.simplefilter(): 6c4, providing a more
     concise way to locally ignore warnings or convert them to errors.

   - gh-91217(77): Deprecate the chunk module.

   - gh-91498(78): Add the ‘TCP_CONNECTION_INFO’ option (available on
     macOS) to *note socket: cc.

   - bpo-47260(79): Fix ‘os.closerange()’ potentially being a no-op in a
     Linux seccomp sandbox.

   - bpo-47087(80): Implement ‘typing.Required’ and ‘typing.NotRequired’
     ( PEP 655(81)).  Patch by David Foster and Jelle Zijlstra.

   - bpo-47061(82): Deprecate cgi and cgitb.

   - bpo-47061(83): Deprecate audioop.

   - bpo-47000(84): Add *note locale.getencoding(): 2dc. to get the
     current locale encoding.  It is similar to
     ‘locale.getpreferredencoding(False)’ but ignores the *note Python
     UTF-8 Mode: 659.

   - bpo-42012(85): Add *note wsgiref.types: 11c, containing
     WSGI-specific types for static type checking.

   - bpo-47227(86): Suppress expression chaining for more *note re: b9.
     parsing errors.

   - bpo-47211(87): Remove undocumented and never working function
     ‘re.template()’ and flag ‘re.TEMPLATE’.  This was later reverted in
     3.11.0b2 and deprecated instead.

   - bpo-47135(88): *note decimal.localcontext(): 13d3. now accepts
     context attributes via keyword arguments

   - bpo-43323(89): Fix errors in the *note email: 3b. module if the
     charset itself contains undecodable/unencodable characters.

   - bpo-46841(90): Disassembly of quickened code.

   - bpo-46681(91): Forward gzip.compress() compresslevel to zlib.

   - bpo-45100(92): Add *note typing.get_overloads(): 6b1. and *note
     typing.clear_overloads(): 6b2.  Patch by Jelle Zijlstra.

   - bpo-44807(93): *note typing.Protocol: 264. no longer silently
     replaces ‘__init__()’ methods defined on subclasses.  Patch by
     Adrian Garcia Badaracco.

   - bpo-46787(94): Fix *note concurrent.futures.ProcessPoolExecutor:
     8f7. exception memory leak

   - bpo-46720(95): Add support for path-like objects to *note
     multiprocessing.set_executable(): 1936. for Windows to be on a par
     with Unix-like systems.  Patch by Géry Ogam.

   - bpo-46696(96): Add ‘SO_INCOMING_CPU’ constant to *note socket: cc.

   - bpo-46053(97): Fix OSS audio support on NetBSD.

   - bpo-45639(98): ‘image/avif’ and ‘image/webp’ were added to *note
     mimetypes: 8f.

   - bpo-46285(99): Add command-line option ‘-p’/‘--protocol’ to module
     *note http.server: 72. which specifies the HTTP version to which
     the server is conformant (HTTP/1.1 conformant servers can now be
     run from the command-line interface of module ‘http.server’).
     Patch by Géry Ogam.

   - bpo-44791(100): Accept ellipsis as the last argument of *note
     typing.Concatenate: 7c8.

   - bpo-46547(101): Remove variables leaking into ‘pydoc.Helper’ class
     namespace.

   - bpo-46415(102): Fix ipaddress.ip_{address,interface,network}
     raising TypeError instead of ValueError if given invalid tuple as
     address parameter.

   - bpo-46075(103): ‘CookieJar’ with ‘DefaultCookiePolicy’ now can
     process cookies from localhost with domain=localhost explicitly
     specified in Set-Cookie header.

   - bpo-45995(104): Add a “z” option to the string formatting
     specification that coerces negative zero floating-point values to
     positive zero after rounding to the format precision.  Contributed
     by John Belmonte.

   - bpo-26175(105): Fully implement the *note io.BufferedIOBase: 697.
     or *note io.TextIOBase: 698. interface for *note
     tempfile.SpooledTemporaryFile: 696. objects.  This lets them work
     correctly with higher-level layers (like compression modules).
     Patch by Carey Metcalfe.

   - bpo-45138(106): Fix a regression in the *note sqlite3: cf. trace
     callback where bound parameters were not expanded in the passed
     statement string.  The regression was introduced in Python 3.10 by
     bpo-40318(107).  Patch by Erlend E. Aasland.

   - bpo-44863(108): Allow *note TypedDict: 162. subclasses to also
     include *note Generic: 15fb. as a base class in class based syntax.
     Thereby allowing the user to define a generic ‘TypedDict’, just
     like a user-defined generic but with ‘TypedDict’ semantics.

   - bpo-44587(109): Fix BooleanOptionalAction to not automatically add
     a default string.  If a default string is desired, use a formatter
     to add it.

   - bpo-43827(110): All positional-or-keyword parameters to
     ‘ABCMeta.__new__’ are now positional-only to avoid conflicts with
     keyword arguments to be passed to ‘__init_subclass__()’.

   - bpo-43218(111): Prevent creation of a venv whose path contains the
     PATH separator.  This could affect the usage of the activate
     script.  Patch by Dustin Rodrigues.

   - bpo-38435(112): Add a ‘process_group’ parameter to *note
     subprocess.Popen: 199. to help move more things off of the unsafe
     ‘preexec_fn’ parameter.

   - bpo-42066(113): Fix cookies getting sorted in
     ‘CookieJar.__iter__()’ which is an extra behavior and not mentioned
     in RFC 2965 or Netscape cookie protocol.  Now the cookies in
     ‘CookieJar’ follows the order of the ‘Set-Cookie’ header.  Patch by
     Iman Kermani.

   - bpo-40617(114): Add *note create_window_function(): 683. to *note
     sqlite3.Connection: 245. for creating aggregate window functions.
     Patch by Erlend E. Aasland.

   - bpo-40676(115): Convert *note csv: 29. to use Argument Clinic for
     *note csv.field_size_limit(): 1937, *note csv.get_dialect(): 1938,
     *note csv.unregister_dialect(): 1939. and *note
     csv.list_dialects(): 193a.

   - bpo-39716(116): Raise an ‘ArgumentError’ when the same subparser
     name is added twice to an ‘argparse.ArgumentParser’.  This is
     consistent with the (default) behavior when the same option string
     is added twice to an ‘ArgumentParser’.

   - bpo-36073(117): Raise *note ProgrammingError: 4f5. instead of
     segfaulting on recursive usage of cursors in *note sqlite3: cf.
     converters.  Patch by Sergey Fedoseev.

   - bpo-34975(118): Adds a ‘start_tls()’ method to ‘StreamWriter’,
     which upgrades the connection with TLS using the given *note
     SSLContext: 294.

   - bpo-22276(119): *note Path: 229. methods *note glob(): 22d. and
     *note rglob(): 22e. return only directories if 'pattern' ends with
     a pathname components separator (‘/’ or *note sep: 66d.).  Patch by
     Eisuke Kawashima.

   - bpo-24905(120): Add *note blobopen(): 684. to *note
     sqlite3.Connection: 245.  *note sqlite3.Blob: 685. allows
     incremental I/O operations on blobs.  Patch by Aviv Palivoda and
     Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87901

   (2) https://github.com/python/cpython/issues/90997

   (3) https://github.com/python/cpython/issues/92332

   (4) https://github.com/python/cpython/issues/78157

   (5) https://github.com/python/cpython/issues/92356

   (6) https://github.com/python/cpython/issues/90997

   (7) https://github.com/python/cpython/issues/92301

   (8) https://github.com/python/cpython/issues/67248

   (9) https://github.com/python/cpython/issues/92210

   (10) https://github.com/python/cpython/issues/80010

   (11) https://github.com/python/cpython/issues/92118

   (12) https://github.com/python/cpython/issues/90887

   (13) https://github.com/python/cpython/issues/91215

   (14) https://github.com/python/cpython/issues/85984

   (15) https://github.com/python/cpython/issues/92128

   (16) https://github.com/python/cpython/issues/92049

   (17) https://github.com/python/cpython/issues/92062

   (18) https://github.com/python/cpython/issues/87390

   (19) https://github.com/python/cpython/issues/88089

   (20) https://github.com/python/cpython/issues/91996

   (21) https://github.com/python/cpython/issues/91984

   (22) https://github.com/python/cpython/issues/91952

   (23) https://github.com/python/cpython/issues/91954

   (24) https://bugs.python.org/issue?@action=redirect&bpo=47029

   (25) https://github.com/python/cpython/issues/91928

   (26) https://github.com/python/cpython/issues/68966

   (27) https://peps.python.org/pep-0594/

   (28) https://github.com/python/cpython/issues/91401

   (29) https://github.com/python/cpython/issues/64783

   (30) https://github.com/python/cpython/issues/91910

   (31) https://github.com/python/cpython/issues/91860

   (32) https://peps.python.org/pep-0681/

   (33) https://github.com/python/cpython/issues/91832

   (34) https://github.com/python/cpython/issues/91827

   (35) https://github.com/python/cpython/issues/84461

   (36) https://github.com/python/cpython/issues/91821

   (37) https://github.com/python/cpython/issues/91217

   (38) https://github.com/python/cpython/issues/91217

   (39) https://github.com/python/cpython/issues/91760

   (40) https://github.com/python/cpython/issues/84461

   (41) https://github.com/python/cpython/issues/90623

   (42) https://github.com/python/cpython/issues/91734

   (43) https://github.com/python/cpython/issues/90633

   (44) https://github.com/python/cpython/issues/91700

   (45) https://github.com/python/cpython/issues/91231

   (46) https://github.com/python/cpython/issues/91621

   (47) https://github.com/python/cpython/issues/90568

   (48) https://github.com/python/cpython/issues/91670

   (49) https://github.com/python/cpython/issues/91217

   (50) https://github.com/python/cpython/issues/91217

   (51) https://github.com/python/cpython/issues/91217

   (52) https://github.com/python/cpython/issues/91217

   (53) https://github.com/python/cpython/issues/91616

   (54) https://github.com/python/cpython/issues/91217

   (55) https://github.com/python/cpython/issues/91217

   (56) https://bugs.python.org/issue?@action=redirect&bpo=47256

   (57) https://github.com/python/cpython/issues/91217

   (58) https://github.com/python/cpython/issues/91595

   (59) https://github.com/python/cpython/issues/74166

   (60) https://github.com/python/cpython/issues/91487

   (61) https://github.com/python/cpython/issues/91575

   (62) https://github.com/python/cpython/issues/90622

   (63) https://github.com/python/cpython/issues/89022

   (64) https://github.com/python/cpython/issues/91526

   (65) https://github.com/python/cpython/issues/88116

   (66) https://peps.python.org/pep-0657/

   (67) https://github.com/python/cpython/issues/69093

   (68) https://github.com/python/cpython/issues/69093

   (69) https://github.com/python/cpython/issues/91217

   (70) https://github.com/python/cpython/issues/91217

   (71) https://github.com/python/cpython/issues/91404

   (72) https://github.com/python/cpython/issues/91217

   (73) https://github.com/python/cpython/issues/91217

   (74) https://github.com/python/cpython/issues/91276

   (75) https://bugs.python.org/issue?@action=redirect&bpo=47000

   (76) https://github.com/python/cpython/issues/91230

   (77) https://github.com/python/cpython/issues/91217

   (78) https://github.com/python/cpython/issues/91498

   (79) https://bugs.python.org/issue?@action=redirect&bpo=47260

   (80) https://bugs.python.org/issue?@action=redirect&bpo=47087

   (81) https://peps.python.org/pep-0655/

   (82) https://bugs.python.org/issue?@action=redirect&bpo=47061

   (83) https://bugs.python.org/issue?@action=redirect&bpo=47061

   (84) https://bugs.python.org/issue?@action=redirect&bpo=47000

   (85) https://bugs.python.org/issue?@action=redirect&bpo=42012

   (86) https://bugs.python.org/issue?@action=redirect&bpo=47227

   (87) https://bugs.python.org/issue?@action=redirect&bpo=47211

   (88) https://bugs.python.org/issue?@action=redirect&bpo=47135

   (89) https://bugs.python.org/issue?@action=redirect&bpo=43323

   (90) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (91) https://bugs.python.org/issue?@action=redirect&bpo=46681

   (92) https://bugs.python.org/issue?@action=redirect&bpo=45100

   (93) https://bugs.python.org/issue?@action=redirect&bpo=44807

   (94) https://bugs.python.org/issue?@action=redirect&bpo=46787

   (95) https://bugs.python.org/issue?@action=redirect&bpo=46720

   (96) https://bugs.python.org/issue?@action=redirect&bpo=46696

   (97) https://bugs.python.org/issue?@action=redirect&bpo=46053

   (98) https://bugs.python.org/issue?@action=redirect&bpo=45639

   (99) https://bugs.python.org/issue?@action=redirect&bpo=46285

   (100) https://bugs.python.org/issue?@action=redirect&bpo=44791

   (101) https://bugs.python.org/issue?@action=redirect&bpo=46547

   (102) https://bugs.python.org/issue?@action=redirect&bpo=46415

   (103) https://bugs.python.org/issue?@action=redirect&bpo=46075

   (104) https://bugs.python.org/issue?@action=redirect&bpo=45995

   (105) https://bugs.python.org/issue?@action=redirect&bpo=26175

   (106) https://bugs.python.org/issue?@action=redirect&bpo=45138

   (107) https://bugs.python.org/issue?@action=redirect&bpo=40318

   (108) https://bugs.python.org/issue?@action=redirect&bpo=44863

   (109) https://bugs.python.org/issue?@action=redirect&bpo=44587

   (110) https://bugs.python.org/issue?@action=redirect&bpo=43827

   (111) https://bugs.python.org/issue?@action=redirect&bpo=43218

   (112) https://bugs.python.org/issue?@action=redirect&bpo=38435

   (113) https://bugs.python.org/issue?@action=redirect&bpo=42066

   (114) https://bugs.python.org/issue?@action=redirect&bpo=40617

   (115) https://bugs.python.org/issue?@action=redirect&bpo=40676

   (116) https://bugs.python.org/issue?@action=redirect&bpo=39716

   (117) https://bugs.python.org/issue?@action=redirect&bpo=36073

   (118) https://bugs.python.org/issue?@action=redirect&bpo=34975

   (119) https://bugs.python.org/issue?@action=redirect&bpo=22276

   (120) https://bugs.python.org/issue?@action=redirect&bpo=24905


File: python.info,  Node: Documentation<27>,  Next: Tests<30>,  Prev: Library<65>,  Up: Python 3 11 0 beta 1

1.23.36.8 Documentation
.......................

   - gh-91888(1): Add a new ‘gh’ role to the documentation to link to
     GitHub issues.

   - gh-91783(2): Document security issues concerning the use of the
     function *note shutil.unpack_archive(): 46e.

   - gh-91547(3): Remove “Undocumented modules” page.

   - gh-91298(4): In ‘importlib.resources.abc’, refined the
     documentation of the Traversable Protocol, applying changes from
     importlib_resources 5.7.1.

   - bpo-44347(5): Clarify the meaning of 'dirs_exist_ok', a kwarg of
     *note shutil.copytree(): a36.

   - bpo-36329(6): Remove ‘make -C Doc serve’ in favour of ‘make -C Doc
     htmlview’

   - bpo-47189(7): Add a What’s New in Python 3.11 entry for the Faster
     CPython project.  Documentation by Ken Jin and Kumar Aditya.

   - bpo-38668(8): Update the introduction to documentation for *note
     os.path: a2. to remove warnings that became irrelevant after the
     implementations of PEP 383(9) and PEP 529(10).

   - bpo-47115(11): The documentation now lists which members of C
     structs are part of the *note Limited API/Stable ABI: 556.

   - bpo-46962(12): All docstrings in code snippets are now wrapped into
     *note PyDoc_STR: 193c. to follow the guideline of PEP 7’s
     Documentation Strings paragraph(13).  Patch by Oleg Iarygin.

   - bpo-26792(14): Improve the docstrings of *note runpy.run_module():
     193d. and *note runpy.run_path(): 181.  Original patch by Andrew
     Brezovsky.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91888

   (2) https://github.com/python/cpython/issues/91783

   (3) https://github.com/python/cpython/issues/91547

   (4) https://github.com/python/cpython/issues/91298

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44347

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36329

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47189

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38668

   (9) https://peps.python.org/pep-0383/

   (10) https://peps.python.org/pep-0529/

   (11) https://bugs.python.org/issue?@action=redirect&bpo=47115

   (12) https://bugs.python.org/issue?@action=redirect&bpo=46962

   (13) https://peps.python.org/pep-0007/#documentation-strings

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26792


File: python.info,  Node: Tests<30>,  Next: Build<33>,  Prev: Documentation<27>,  Up: Python 3 11 0 beta 1

1.23.36.9 Tests
...............

   - gh-92169(1): Use ‘warnings_helper.import_deprecated()’ to import
     deprecated modules uniformly in tests.  Patch by Hugo van Kemenade.

   - gh-84461(2): When multiprocessing is enabled, libregrtest can now
     use a Python executable other than ‘sys.executable’ via the
     ‘--python’ flag.

   - gh-91904(3): Fix initialization of ‘PYTHONREGRTEST_UNICODE_GUARD’
     which prevented running regression tests on non-UTF-8 locale.

   - gh-91752(4): Added @requires_zlib to
     test.test_tools.test_freeze.TestFreeze.

   - gh-91607(5): Fix ‘test_concurrent_futures’ to test the correct
     multiprocessing start method context in several cases where the
     test logic mixed this up.

   - bpo-40280(6): Threading tests are now skipped on WASM targets
     without pthread support.

   - bpo-47109(7): Test for ‘ctypes.macholib.dyld’,
     ‘ctypes.macholib.dylib’, and ‘ctypes.macholib.framework’ are
     brought from manual pre-*note unittest: 106. times to ‘ctypes.test’
     location and structure.  Patch by Oleg Iarygin.

   - bpo-29890(8): Add tests for *note ipaddress.IPv4Interface: 193f.
     and *note ipaddress.IPv6Interface: 1940. construction with tuple
     arguments.  Original patch and tests by louisom.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92169

   (2) https://github.com/python/cpython/issues/84461

   (3) https://github.com/python/cpython/issues/91904

   (4) https://github.com/python/cpython/issues/91752

   (5) https://github.com/python/cpython/issues/91607

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47109

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29890


File: python.info,  Node: Build<33>,  Next: Windows<28>,  Prev: Tests<30>,  Up: Python 3 11 0 beta 1

1.23.36.10 Build
................

   - gh-89452(1): gdbm-compat is now preferred over ndbm if both are
     available on the system.  This allows avoiding the problematic
     ndbm.h on macOS.

   - gh-91731(2): Python is now built with ‘-std=c11’ compiler option,
     rather than ‘-std=c99’.  Patch by Victor Stinner.

   - bpo-47152(3): Add script and make target for generating
     ‘sre_constants.h’.

   - bpo-47103(4): Windows ‘PGInstrument’ builds now copy a required DLL
     into the output directory, making it easier to run the profile
     stage of a PGO build.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89452

   (2) https://github.com/python/cpython/issues/91731

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47152

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47103


File: python.info,  Node: Windows<28>,  Next: macOS<21>,  Prev: Build<33>,  Up: Python 3 11 0 beta 1

1.23.36.11 Windows
..................

   - bpo-46907(1): Update Windows installer to use SQLite 3.38.3.

   - bpo-47239(2): Fixed –list and –list-paths output for *note Python
     Launcher for Windows: 5c1. when used in an active virtual
     environment.

   - bpo-46907(3): Update Windows installer to use SQLite 3.38.2.

   - bpo-46785(4): Fix race condition between *note os.stat(): 4a3. and
     unlinking a file on Windows, by using errors codes returned by
     ‘FindFirstFileW()’ when appropriate in ‘win32_xstat_impl’.

   - bpo-40859(5): Update Windows build to use xz-5.2.5

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46907

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47239

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46907

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46785

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40859


File: python.info,  Node: macOS<21>,  Next: Tools/Demos<18>,  Prev: Windows<28>,  Up: Python 3 11 0 beta 1

1.23.36.12 macOS
................

   - bpo-46907(1): Update macOS installer to SQLite 3.38.4.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46907


File: python.info,  Node: Tools/Demos<18>,  Next: C API<29>,  Prev: macOS<21>,  Up: Python 3 11 0 beta 1

1.23.36.13 Tools/Demos
......................

   - gh-91583(1): Fix regression in the code generated by Argument
     Clinic for functions with the ‘defining_class’ parameter.

   - gh-91575(2): Add script ‘Tools/scripts/generate_re_casefix.py’ and
     the make target ‘regen-re’ for generating additional data for
     case-insensitive matching according to the current Unicode version.

   - gh-91551(3): Remove the ancient Pynche color editor.  It has moved
     to ‘https://gitlab.com/warsaw/pynche’

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91583

   (2) https://github.com/python/cpython/issues/91575

   (3) https://github.com/python/cpython/issues/91551


File: python.info,  Node: C API<29>,  Prev: Tools/Demos<18>,  Up: Python 3 11 0 beta 1

1.23.36.14 C API
................

   - gh-88279(1): Deprecate the C functions: ‘PySys_SetArgv()’,
     ‘PySys_SetArgvEx()’, ‘PySys_SetPath()’.  Patch by Victor Stinner.

   - gh-92154(2): Added the *note PyCode_GetCode(): 77b. function.  This
     function does the equivalent of the Python code
     ‘getattr(code_object, 'co_code')’.

   - gh-92173(3): Fix the ‘closure’ argument to *note
     PyEval_EvalCodeEx(): 187d.

   - gh-91320(4): Fix C++ compiler warnings about “old-style cast” (‘g++
     -Wold-style-cast’) in the Python C API. Use C++
     ‘reinterpret_cast<>’ and ‘static_cast<>’ casts when the Python C
     API is used in C++.  Patch by Victor Stinner.

   - gh-80527(5): Mark functions as deprecated by PEP 623(6):
     ‘PyUnicode_AS_DATA()’, ‘PyUnicode_AS_UNICODE()’,
     ‘PyUnicode_GET_DATA_SIZE()’, ‘PyUnicode_GET_SIZE()’.  Patch by
     Victor Stinner.

   - gh-91768(7): *note Py_REFCNT(): 8b1, *note Py_TYPE(): 783, *note
     Py_SIZE(): 785. and *note Py_IS_TYPE(): 1946. functions argument
     type is now ‘PyObject*’, rather than ‘const PyObject*’.  Patch by
     Victor Stinner.

   - gh-91020(8): Add ‘PyBytes_Type.tp_alloc’ to initialize
     ‘PyBytesObject.ob_shash’ for bytes subclasses.

   - bpo-40421(9): Add ‘PyFrame_GetLasti’ C-API function to access frame
     object’s ‘f_lasti’ attribute safely from C code.

   - bpo-35134(10): Remove the ‘Include/code.h’ header file.  C
     extensions should only include the main ‘<Python.h>’ header file.
     Patch by Victor Stinner.

   - bpo-47169(11): *note PyOS_CheckStack(): 1947. is now exported in
     the Stable ABI on Windows.

   - bpo-47169(12): *note PyThread_get_thread_native_id(): 1948. is
     excluded from the stable ABI on platforms where it doesn’t exist
     (like Solaris).

   - bpo-46343(13): Added *note PyErr_GetHandledException(): 772. and
     *note PyErr_SetHandledException(): 773. as simpler alternatives to
     *note PyErr_GetExcInfo(): 775. and *note PyErr_SetExcInfo(): 774.

     They are included in the stable ABI.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/88279

   (2) https://github.com/python/cpython/issues/92154

   (3) https://github.com/python/cpython/issues/92173

   (4) https://github.com/python/cpython/issues/91320

   (5) https://github.com/python/cpython/issues/80527

   (6) https://peps.python.org/pep-0623/

   (7) https://github.com/python/cpython/issues/91768

   (8) https://github.com/python/cpython/issues/91020

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (11) https://bugs.python.org/issue?@action=redirect&bpo=47169

   (12) https://bugs.python.org/issue?@action=redirect&bpo=47169

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46343


File: python.info,  Node: Python 3 11 0 alpha 7,  Next: Python 3 11 0 alpha 6,  Prev: Python 3 11 0 beta 1,  Up: Changelog

1.23.37 Python 3.11.0 alpha 7
-----------------------------

'Release date: 2022-04-05'

* Menu:

* Core and Builtins: Core and Builtins<64>.
* Library: Library<66>.
* Core and Builtins: Core and Builtins<65>.
* Library: Library<67>.
* Core and Builtins: Core and Builtins<66>.
* Library: Library<68>.
* Documentation: Documentation<28>.
* Tests: Tests<31>.
* Build: Build<34>.
* Windows: Windows<29>.
* macOS: macOS<22>.
* Tools/Demos: Tools/Demos<19>.
* C API: C API<30>.


File: python.info,  Node: Core and Builtins<64>,  Next: Library<66>,  Up: Python 3 11 0 alpha 7

1.23.37.1 Core and Builtins
...........................

   - bpo-47212(1): Raise *note IndentationError: 7ac. instead of *note
     SyntaxError: 18d. for a bare ‘except’ with no following indent.
     Improve ‘SyntaxError’ locations for an un-parenthesized generator
     used as arguments.  Patch by Matthieu Dartiailh.

   - bpo-47186(2): Replace ‘JUMP_IF_NOT_EG_MATCH’ by *note
     CHECK_EG_MATCH: 705. + jump.

   - bpo-47176(3): Emscripten builds cannot handle signals in the usual
     way due to platform limitations.  Python can now handle signals.
     To use, set Module.Py_EmscriptenSignalBuffer to be a single byte
     SharedArrayBuffer and set Py_EMSCRIPTEN_SIGNAL_HANDLING to 1.
     Writing a number into the SharedArrayBuffer will cause the
     corresponding signal to be raised into the Python thread.

   - bpo-47186(4): Replace ‘JUMP_IF_NOT_EXC_MATCH’ by *note
     CHECK_EXC_MATCH: 70e. + jump.

   - bpo-47120(5): Replace the absolute jump opcode *note
     JUMP_NO_INTERRUPT: 194b. by the relative *note
     JUMP_BACKWARD_NO_INTERRUPT: 702.

   - bpo-46841(6): Avoid unnecessary allocations when comparing code
     objects.

   - bpo-47182(7): Fix a crash when using a named unicode character like
     ‘"\N{digit nine}"’ after the main interpreter has been initialized
     a second time.

   - bpo-47162(8): WebAssembly cannot deal with bad function pointer
     casts (different count or types of arguments).  Python can now use
     call trampolines to mitigate the problem.  Define
     ‘PY_CALL_TRAMPOLINE’ to enable call trampolines.

   - bpo-46775(9): Some Windows system error codes(>= 10000) are now
     mapped into the correct errno and may now raise a subclass of *note
     OSError: 41a.  Patch by Donghee Na.

   - bpo-47129(10): Improve error messages in f-string syntax errors
     concerning empty expressions.

   - bpo-47117(11): Fix a crash if we fail to decode characters in
     interactive mode if the tokenizer buffers are uninitialized.  Patch
     by Pablo Galindo.

   - bpo-47127(12): Speed up calls to c functions with keyword arguments
     by 25% with specialization.  Patch by Kumar Aditya.

   - bpo-47120(13): Replaced ‘JUMP_ABSOLUTE’ by the relative jump *note
     JUMP_BACKWARD: 70f.

   - bpo-42197(14): ‘PyFrame_FastToLocalsWithError()’ and
     ‘PyFrame_LocalsToFast()’ are no longer called during profiling nor
     tracing.  C code can access the ‘f_locals’ attribute of *note
     PyFrameObject: 78c. by calling *note PyFrame_GetLocals(): 422.

   - bpo-47070(15): Improve performance of ‘array_inplace_repeat’ by
     reducing the number of invocations of ‘memcpy’.  Refactor the
     ‘repeat’ and inplace ‘repeat’ methods of ‘array’, ‘bytes’,
     ‘bytearray’ and ‘unicodeobject’ to use the common
     ‘_PyBytes_Repeat’.

   - bpo-47053(16): Reduce de-optimization in the specialized
     ‘BINARY_OP_INPLACE_ADD_UNICODE’ opcode.

   - bpo-47045(17): Remove the ‘f_state’ field from the
     _PyInterpreterFrame struct.  Add the ‘owner’ field to the
     _PyInterpreterFrame struct to make ownership explicit to simplify
     clearing and deallocing frames and generators.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47212

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47186

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47176

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47186

   (5) https://bugs.python.org/issue?@action=redirect&bpo=47120

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47182

   (8) https://bugs.python.org/issue?@action=redirect&bpo=47162

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46775

   (10) https://bugs.python.org/issue?@action=redirect&bpo=47129

   (11) https://bugs.python.org/issue?@action=redirect&bpo=47117

   (12) https://bugs.python.org/issue?@action=redirect&bpo=47127

   (13) https://bugs.python.org/issue?@action=redirect&bpo=47120

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42197

   (15) https://bugs.python.org/issue?@action=redirect&bpo=47070

   (16) https://bugs.python.org/issue?@action=redirect&bpo=47053

   (17) https://bugs.python.org/issue?@action=redirect&bpo=47045


File: python.info,  Node: Library<66>,  Next: Core and Builtins<65>,  Prev: Core and Builtins<64>,  Up: Python 3 11 0 alpha 7

1.23.37.2 Library
.................

   - bpo-46968(1): Check for the existence of the “sys/auxv.h” header in
     *note faulthandler: 58. to avoid compilation problems in systems
     where this header doesn’t exist.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46968


File: python.info,  Node: Core and Builtins<65>,  Next: Library<67>,  Prev: Library<66>,  Up: Python 3 11 0 alpha 7

1.23.37.3 Core and Builtins
...........................

   - bpo-46329(1): Use low bit of ‘LOAD_GLOBAL’ to indicate whether to
     push a ‘NULL’ before the global.  Helps streamline the call
     sequence a bit.

   - bpo-46841(2): Quicken bytecode in-place by storing it as part of
     the corresponding ‘PyCodeObject’.

   - bpo-47012(3): Speed up iteration of *note bytes: 1c2. and *note
     bytearray: 2ea. by 30%.  Patch by Kumar Aditya.

   - bpo-47009(4): Improved the performance of *note list.append(): 6d0.
     and list comprehensions by optimizing for the common case, where no
     resize is needed.  Patch by Dennis Sweeney.

   - bpo-47005(5): Improve performance of ‘bytearray_repeat’ and
     ‘bytearray_irepeat’ by reducing the number of invocations of
     ‘memcpy’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46329

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47012

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47009

   (5) https://bugs.python.org/issue?@action=redirect&bpo=47005


File: python.info,  Node: Library<67>,  Next: Core and Builtins<66>,  Prev: Core and Builtins<65>,  Up: Python 3 11 0 alpha 7

1.23.37.4 Library
.................

   - bpo-46829(1): Deprecate passing a message into *note
     asyncio.Future.cancel(): 194f. and *note asyncio.Task.cancel():
     1b7.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46829


File: python.info,  Node: Core and Builtins<66>,  Next: Library<68>,  Prev: Library<67>,  Up: Python 3 11 0 alpha 7

1.23.37.5 Core and Builtins
...........................

   - bpo-46993(1): Speed up *note bytearray: 2ea. creation from *note
     list: 614. and *note tuple: 373. by 40%.  Patch by Kumar Aditya.

   - bpo-39829(2): Removed the ‘__len__()’ call when initializing a list
     and moved initializing to ‘list_extend’.  Patch by Jeremiah
     Pascual.

   - bpo-46944(3): Speed up throwing exception in generator with *note
     METH_FASTCALL: 1731. calling convention.  Patch by Kumar Aditya.

   - bpo-46841(4): Modify *note STORE_SUBSCR: 1951. to use an inline
     cache entry (rather than its oparg) as an adaptive counter.

   - bpo-46841(5): Use inline caching for ‘PRECALL’ and *note CALL: 70a,
     and remove the internal machinery for managing the (now unused)
     non-inline caches.

   - bpo-46881(6): Statically allocate and initialize the latin1
     characters.

   - bpo-46838(7): Improve syntax errors for incorrect function
     definitions.  Patch by Pablo Galindo

   - bpo-43721(8): Fix docstrings of *note getter: 176d, *note setter:
     176e, and *note deleter: 176f. to clarify that they create a new
     copy of the property.

   - bpo-43224(9): Make grammar changes required for PEP 646.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46993

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39829

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46944

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46881

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46838

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43721

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43224


File: python.info,  Node: Library<68>,  Next: Documentation<28>,  Prev: Core and Builtins<66>,  Up: Python 3 11 0 alpha 7

1.23.37.6 Library
.................

   - bpo-47208(1): Allow vendors to override ‘CTYPES_MAX_ARGCOUNT’.

   - bpo-23689(2): *note re: b9. module: fix memory leak when a match is
     terminated by a signal or memory allocation failure.  Patch by Ma
     Lin.

   - bpo-47167(3): Allow overriding a future compliance check in *note
     asyncio.Task: 1be.

   - bpo-47151(4): When subprocess tries to use vfork, it now falls back
     to fork if vfork returns an error.  This allows use in situations
     where vfork isn’t allowed by the OS kernel.

   - bpo-47152(5): Convert the *note re: b9. module into a package.
     Deprecate modules ‘sre_compile’, ‘sre_constants’ and ‘sre_parse’.

   - bpo-4833(6): Add ‘ZipFile.mkdir()’

   - bpo-27929(7): Fix *note asyncio.loop.sock_connect(): df8. to only
     resolve names for *note socket.AF_INET: 1953. or *note
     socket.AF_INET6: 1954. families.  Resolution may not make sense for
     other families, like ‘socket.AF_BLUETOOTH’ and *note
     socket.AF_UNIX: 1955.

   - bpo-14265(8): Adds the fully qualified test name to unittest output

   - bpo-47061(9): Deprecate the aifc module.

   - bpo-39622(10): Handle Ctrl+C in asyncio programs to interrupt the
     main task.

   - bpo-47101(11): *note hashlib.algorithms_available: 13c1. now lists
     only algorithms that are provided by activated crypto providers on
     OpenSSL 3.0.  Legacy algorithms are not listed unless the legacy
     provider has been loaded into the default OSSL context.

   - bpo-47099(12): All ‘URLError’ exception messages raised in *note
     urllib.request.URLopener: 30e. now contain a colon between ‘ftp
     error’ and the rest of the message.  Previously, ‘open_ftp()’
     missed the colon.  Patch by Oleg Iarygin.

   - bpo-47099(13): Exception chaining is changed from
     ‘Exception.with_traceback()’/*note sys.exc_info(): 68d. to PEP
     3134(14).  Patch by Oleg Iarygin.

   - bpo-47095(15): *note hashlib: 68.’s internal ‘_blake2’ module now
     prefers ‘libb2’ from ‘https://www.blake2.net/’ over Python’s
     vendored copy of blake2.

   - bpo-47098(16): The Keccak Code Package for *note hashlib: 68.’s
     internal ‘_sha3’ module has been replaced with tiny_sha3.  The
     module is used as fallback when Python is built without OpenSSL.

   - bpo-47088(17): Implement *note typing.LiteralString: 5cd, part of
     PEP 675(18).  Patch by Jelle Zijlstra.

   - bpo-42885(19): Optimize *note re.search(): 1272, *note re.split():
     2a2, *note re.findall(): 1065, *note re.finditer(): 1549. and *note
     re.sub(): 2a3. for regular expressions starting with ‘\A’ or ‘^’.

   - bpo-23691(20): Protect the *note re.finditer(): 1549. iterator from
     re-entering.

   - bpo-47067(21): Optimize calling ‘GenericAlias’ objects by using PEP
     590(22) ‘vectorcall’ and by replacing ‘PyObject_SetAttrString’ with
     ‘PyObject_SetAttr’.

   - bpo-28080(23): Add the 'metadata_encoding' parameter in the *note
     zipfile.ZipFile: 6c7. constructor and the ‘--metadata-encoding’
     option in the *note zipfile: 131. CLI to allow reading zipfiles
     using non-standard codecs to encode the filenames within the
     archive.

   - bpo-47000(24): Make *note io.text_encoding(): 17d6. returns “utf-8”
     when UTF-8 mode is enabled.

   - bpo-42369(25): Fix thread safety of ‘zipfile._SharedFile.tell()’ to
     avoid a “zipfile.BadZipFile: Bad CRC-32 for file” exception when
     reading a ‘ZipFile’ from multiple threads.

   - bpo-38256(26): Fix *note binascii.crc32(): 17a9. when it is
     compiled to use zlib’c crc32 to work properly on inputs 4+GiB in
     length instead of returning the wrong result.  The workaround prior
     to this was to always feed the function data in increments smaller
     than 4GiB or to just call the zlib module function.

     We also have *note binascii.crc32(): 17a9. release the GIL when
     computing on larger inputs as *note zlib.crc32(): 17a8. and *note
     hashlib: 68. do.

     This also boosts performance on Windows as it now uses the zlib
     crc32 implementation for *note binascii.crc32(): 17a9. for a 2-3x
     speedup.

     That the stdlib has a crc32 API in two modules is a known
     historical oddity.  This moves us closer to a single implementation
     behind them.

   - bpo-47066(27): Global inline flags (e.g.  ‘(?i)’) can now only be
     used at the start of the regular expressions.  Using them not at
     the start of expression was deprecated since Python 3.6.

   - bpo-39394(28): A warning about inline flags not at the start of the
     regular expression now contains the position of the flag.

   - bpo-433030(29): Add support of atomic grouping (‘(?>...)’) and
     possessive quantifiers (‘*+’, ‘++’, ‘?+’, ‘{m,n}+’) in *note
     regular expressions: b9.

   - bpo-47062(30): Implement *note asyncio.Runner: 603. context
     manager.

   - bpo-46382(31): *note dataclass(): 1cb. ‘slots=True’ now correctly
     omits slots already defined in base classes.  Patch by Arie
     Bovenberg.

   - bpo-47057(32): Use FASTCALL convention for ‘FutureIter.throw()’

   - bpo-47061(33): Deprecate the various modules listed by PEP 594(34):

     aifc, asynchat, asyncore, audioop, cgi, cgitb, chunk, crypt,
     imghdr, msilib, nntplib, nis, ossaudiodev, pipes, smtpd, sndhdr,
     spwd, sunau, telnetlib, uu, xdrlib

   - bpo-34790(35): Remove passing coroutine objects to *note
     asyncio.wait(): 482.

   - bpo-47039(36): Normalize ‘repr()’ of asyncio future and task
     objects.

   - bpo-2604(37): Fix bug where doctests using globals would fail when
     run multiple times.

   - bpo-45150(38): Add *note hashlib.file_digest(): 647. helper for
     efficient hashing of file object.

   - bpo-34861(39): Made cumtime the default sorting key for cProfile

   - bpo-45997(40): Fix *note asyncio.Semaphore: a83. re-aquiring FIFO
     order.

   - bpo-47022(41): The ‘asynchat’, ‘asyncore’ and ‘smtpd’ modules have
     been deprecated since at least Python 3.6.  Their documentation and
     deprecation warnings and have now been updated to note they will
     removed in Python 3.12 ( PEP 594(42)).

   - bpo-43253(43): Fix a crash when closing transports where the
     underlying socket handle is already invalid on the Proactor event
     loop.

   - bpo-40280(44): *note select.select(): dce. now passes ‘NULL’ to
     ‘select’ for each empty fdset.

   - bpo-47004(45): Apply bugfixes from importlib_metadata 4.11.3,
     including bugfix for EntryPoint.extras, which was returning match
     objects and not the extras strings.

   - bpo-46998(46): Allow subclassing of *note typing.Any: 6af.  Patch
     by Shantanu Jain.

   - bpo-46995(47): Deprecate missing *note asyncio.Task.set_name():
     9e8. for third-party task implementations, schedule making it
     mandatory in Python 3.13.

   - bpo-46994(48): Accept explicit contextvars.Context in *note
     asyncio.create_task(): 1bf. and *note asyncio.loop.create_task():
     1c0.

   - bpo-46981(49): ‘typing.get_args(typing.Tuple[()])’ now returns ‘()’
     instead of ‘((),)’.

   - bpo-46968(50): Add ‘os.sysconf_names['SC_MINSIGSTKSZ']’.

   - bpo-46985(51): Upgrade pip wheel bundled with ensurepip (pip
     22.0.4)

   - bpo-46968(52): *note faulthandler: 58.: On Linux 5.14 and newer,
     dynamically determine size of signal handler stack size CPython
     allocates using ‘getauxval(AT_MINSIGSTKSZ)’.  This changes allows
     for Python extension’s request to Linux kernel to use AMX_TILE
     instruction set on Sapphire Rapids Xeon processor to succeed,
     unblocking use of the ISA in frameworks.

   - bpo-46917(53): The *note math.nan: 666. value is now always
     available.  Patch by Victor Stinner.

   - bpo-46955(54): Expose ‘asyncio.base_events.Server’ as *note
     asyncio.Server: b2b.  Patch by Stefan Zabka.

   - bpo-23325(55): The *note signal: c6. module no longer assumes that
     *note SIG_IGN: 1956. and *note SIG_DFL: 1957. are small int
     singletons.

   - bpo-46932(56): Update bundled libexpat to 2.4.7

   - bpo-46933(57): The *note pwd: b2. module is now optional.  *note
     os.path.expanduser(): a21. returns the path when the ‘pwd’ module
     is not available.

   - bpo-40059(58): PEP 680(59), the *note tomllib: fc. module.  Adds
     support for parsing TOML.

   - bpo-464471(60): *note asyncio.timeout(): 601. and *note
     asyncio.timeout_at(): 1958. context managers added.  Patch by Tin
     Tvrtković and Andrew Svetlov.

   - bpo-46805(61): Added raw datagram socket functions for asyncio:
     ‘sock_sendto()’, ‘sock_recvfrom()’ and ‘sock_recvfrom_into()’.

   - bpo-46644(62): No longer require valid typeforms to be callable.
     This allows *note typing.Annotated: 947. to wrap *note
     typing.ParamSpecArgs: 7ca. and *note dataclasses.InitVar: 1959.
     Patch by Gregory Beauregard.

   - bpo-46581(63): Brings ‘ParamSpec’ propagation for ‘GenericAlias’ in
     line with ‘Concatenate’ (and others).

   - bpo-45413(64): Define 'posix_venv' and 'nt_venv' *note sysconfig
     installation schemes: 692. to be used for bootstrapping new virtual
     environments.  Add 'venv' sysconfig installation scheme to get the
     appropriate one of the above.  The schemes are identical to the
     pre-existing 'posix_prefix' and 'nt' install schemes.  The *note
     venv: 111. module now uses the 'venv' scheme to create new virtual
     environments instead of hardcoding the paths depending only on the
     platform.  Downstream Python distributors customizing the
     'posix_prefix' or 'nt' install scheme in a way that is not
     compatible with the install scheme used in virtual environments are
     encouraged not to customize the 'venv' schemes.  When Python itself
     runs in a virtual environment, *note
     sysconfig.get_default_scheme(): 195a. and *note
     sysconfig.get_preferred_scheme(): 693. with ‘key="prefix"’ returns
     'venv'.

   - bpo-43224(65): Implement support for PEP 646 in typing.py.

   - bpo-43224(66): Allow unpacking types.GenericAlias objects, e.g.
     ‘*tuple[int, str]’.

   - bpo-46557(67): Warnings captured by the logging module are now
     logged without a format string to prevent systems that group logs
     by the msg argument from grouping captured warnings together.

   - bpo-41370(68): *note typing.get_type_hints(): 6b4. now supports
     evaluating strings as forward references in *note PEP 585 generic
     aliases: 6b5.

   - bpo-46607(69): Add *note DeprecationWarning: 1a5. to
     ‘LegacyInterpolation’, deprecated in the docstring since Python
     3.2.  Will be removed in Python 3.13.  Use ‘BasicInterpolation’ or
     ‘ExtendedInterpolation’ instead.

   - bpo-26120(70): *note pydoc: b5. now excludes __future__ imports
     from the module’s data items.

   - bpo-46480(71): Add *note typing.assert_type(): 6ae.  Patch by Jelle
     Zijlstra.

   - bpo-46421(72): Fix a unittest issue where if the command was
     invoked as ‘python -m unittest’ and the filename(s) began with a
     dot (.), a ‘ValueError’ is returned.

   - bpo-46245(73): Add optional parameter 'dir_fd' in *note
     shutil.rmtree(): 301.

   - bpo-22859(74): ‘unittest.TestProgram.usageExit()’ is marked as
     deprecated, to be removed in Python 3.13.

   - bpo-46170(75): Improve the error message when you try to subclass
     an instance of *note typing.NewType: d1c.

   - bpo-40296(76): Fix supporting generic aliases in *note pydoc: b5.

   - bpo-20392(77): Fix inconsistency with uppercase file extensions in
     ‘MimeTypes.guess_type()’.  Patch by Kumar Aditya.

   - bpo-46030(78): Add ‘LOCAL_CREDS’, ‘LOCAL_CREDS_PERSISTENT’ and
     ‘SCM_CREDS2’ FreeBSD constants to the socket module.

   - bpo-44439(79): Fix ‘.write()’ method of a member file in ‘ZipFile’,
     when the input data is an object that supports the buffer protocol,
     the file length may be wrong.

   - bpo-45171(80): Fix handling of the ‘stacklevel’ argument to logging
     functions in the *note logging: 87. module so that it is consistent
     across all logging functions and, as advertised, similar to the
     ‘stacklevel’ argument used in *note warn(): 1569.

   - bpo-24959(81): Fix bug where *note unittest: 106. sometimes drops
     frames from tracebacks of exceptions raised in tests.

   - bpo-44859(82): Raise more accurate and PEP 249(83) compatible
     exceptions in *note sqlite3: cf.

        * Raise *note InterfaceError: 680. instead of *note
          ProgrammingError: 4f5. for ‘SQLITE_MISUSE’ errors.

        * Don’t overwrite *note BufferError: 15e3. with *note
          ValueError: 202. when conversion to BLOB fails.

        * Raise *note ProgrammingError: 4f5. instead of *note Warning:
          195b. if user tries to *note execute(): 2d1. more than one SQL
          statement.

        * Raise *note ProgrammingError: 4f5. instead of *note
          ValueError: 202. if an SQL query contains null characters.

   - bpo-44493(84): Add missing terminated NUL in sockaddr_un’s length

     This was potentially observable when using non-abstract AF_UNIX
     datagram sockets to processes written in another programming
     language.

   - bpo-41930(85): Add *note serialize(): 681. and *note deserialize():
     682. support to *note sqlite3: cf.  Patch by Erlend E. Aasland.

   - bpo-33178(86): Added *note ctypes.BigEndianUnion: 195c. and *note
     ctypes.LittleEndianUnion: 195d. classes, as originally documented
     in the library docs but not yet implemented.

   - bpo-43352(87): Add an Barrier object in synchronization primitives
     of 'asyncio' Lib in order to be consistent with Barrier from
     'threading' and 'multiprocessing' libs*

   - bpo-35859(88): *note re: b9. module, fix a few bugs about capturing
     group.  In rare cases, capturing group gets an incorrect string.
     Patch by Ma Lin.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47208

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23689

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47167

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47151

   (5) https://bugs.python.org/issue?@action=redirect&bpo=47152

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4833

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27929

   (8) https://bugs.python.org/issue?@action=redirect&bpo=14265

   (9) https://bugs.python.org/issue?@action=redirect&bpo=47061

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39622

   (11) https://bugs.python.org/issue?@action=redirect&bpo=47101

   (12) https://bugs.python.org/issue?@action=redirect&bpo=47099

   (13) https://bugs.python.org/issue?@action=redirect&bpo=47099

   (14) https://peps.python.org/pep-3134/

   (15) https://bugs.python.org/issue?@action=redirect&bpo=47095

   (16) https://bugs.python.org/issue?@action=redirect&bpo=47098

   (17) https://bugs.python.org/issue?@action=redirect&bpo=47088

   (18) https://peps.python.org/pep-0675/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=42885

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23691

   (21) https://bugs.python.org/issue?@action=redirect&bpo=47067

   (22) https://peps.python.org/pep-0590/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=28080

   (24) https://bugs.python.org/issue?@action=redirect&bpo=47000

   (25) https://bugs.python.org/issue?@action=redirect&bpo=42369

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38256

   (27) https://bugs.python.org/issue?@action=redirect&bpo=47066

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39394

   (29) https://bugs.python.org/issue?@action=redirect&bpo=433030

   (30) https://bugs.python.org/issue?@action=redirect&bpo=47062

   (31) https://bugs.python.org/issue?@action=redirect&bpo=46382

   (32) https://bugs.python.org/issue?@action=redirect&bpo=47057

   (33) https://bugs.python.org/issue?@action=redirect&bpo=47061

   (34) https://peps.python.org/pep-0594/

   (35) https://bugs.python.org/issue?@action=redirect&bpo=34790

   (36) https://bugs.python.org/issue?@action=redirect&bpo=47039

   (37) https://bugs.python.org/issue?@action=redirect&bpo=2604

   (38) https://bugs.python.org/issue?@action=redirect&bpo=45150

   (39) https://bugs.python.org/issue?@action=redirect&bpo=34861

   (40) https://bugs.python.org/issue?@action=redirect&bpo=45997

   (41) https://bugs.python.org/issue?@action=redirect&bpo=47022

   (42) https://peps.python.org/pep-0594/

   (43) https://bugs.python.org/issue?@action=redirect&bpo=43253

   (44) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (45) https://bugs.python.org/issue?@action=redirect&bpo=47004

   (46) https://bugs.python.org/issue?@action=redirect&bpo=46998

   (47) https://bugs.python.org/issue?@action=redirect&bpo=46995

   (48) https://bugs.python.org/issue?@action=redirect&bpo=46994

   (49) https://bugs.python.org/issue?@action=redirect&bpo=46981

   (50) https://bugs.python.org/issue?@action=redirect&bpo=46968

   (51) https://bugs.python.org/issue?@action=redirect&bpo=46985

   (52) https://bugs.python.org/issue?@action=redirect&bpo=46968

   (53) https://bugs.python.org/issue?@action=redirect&bpo=46917

   (54) https://bugs.python.org/issue?@action=redirect&bpo=46955

   (55) https://bugs.python.org/issue?@action=redirect&bpo=23325

   (56) https://bugs.python.org/issue?@action=redirect&bpo=46932

   (57) https://bugs.python.org/issue?@action=redirect&bpo=46933

   (58) https://bugs.python.org/issue?@action=redirect&bpo=40059

   (59) https://peps.python.org/pep-0680/

   (60) https://bugs.python.org/issue?@action=redirect&bpo=464471

   (61) https://bugs.python.org/issue?@action=redirect&bpo=46805

   (62) https://bugs.python.org/issue?@action=redirect&bpo=46644

   (63) https://bugs.python.org/issue?@action=redirect&bpo=46581

   (64) https://bugs.python.org/issue?@action=redirect&bpo=45413

   (65) https://bugs.python.org/issue?@action=redirect&bpo=43224

   (66) https://bugs.python.org/issue?@action=redirect&bpo=43224

   (67) https://bugs.python.org/issue?@action=redirect&bpo=46557

   (68) https://bugs.python.org/issue?@action=redirect&bpo=41370

   (69) https://bugs.python.org/issue?@action=redirect&bpo=46607

   (70) https://bugs.python.org/issue?@action=redirect&bpo=26120

   (71) https://bugs.python.org/issue?@action=redirect&bpo=46480

   (72) https://bugs.python.org/issue?@action=redirect&bpo=46421

   (73) https://bugs.python.org/issue?@action=redirect&bpo=46245

   (74) https://bugs.python.org/issue?@action=redirect&bpo=22859

   (75) https://bugs.python.org/issue?@action=redirect&bpo=46170

   (76) https://bugs.python.org/issue?@action=redirect&bpo=40296

   (77) https://bugs.python.org/issue?@action=redirect&bpo=20392

   (78) https://bugs.python.org/issue?@action=redirect&bpo=46030

   (79) https://bugs.python.org/issue?@action=redirect&bpo=44439

   (80) https://bugs.python.org/issue?@action=redirect&bpo=45171

   (81) https://bugs.python.org/issue?@action=redirect&bpo=24959

   (82) https://bugs.python.org/issue?@action=redirect&bpo=44859

   (83) https://peps.python.org/pep-0249/

   (84) https://bugs.python.org/issue?@action=redirect&bpo=44493

   (85) https://bugs.python.org/issue?@action=redirect&bpo=41930

   (86) https://bugs.python.org/issue?@action=redirect&bpo=33178

   (87) https://bugs.python.org/issue?@action=redirect&bpo=43352

   (88) https://bugs.python.org/issue?@action=redirect&bpo=35859


File: python.info,  Node: Documentation<28>,  Next: Tests<31>,  Prev: Library<68>,  Up: Python 3 11 0 alpha 7

1.23.37.7 Documentation
.......................

   - bpo-45099(1): Document internal *note asyncio: a. API.

   - bpo-47126(2): Update PEP URLs to PEP 676(3)’s new canonical form.

   - bpo-47040(4): Clarified the old Python versions compatibility note
     of *note binascii.crc32(): 17a9. / *note zlib.adler32(): 195f. /
     *note zlib.crc32(): 17a8. functions.

   - bpo-46033(5): Clarify ‘for’ statement execution in its doc.

   - bpo-45790(6): Adjust inaccurate phrasing in *note Defining
     Extension Types; Tutorial: 1960. about the ‘ob_base’ field and the
     macros used to access its contents.

   - bpo-42340(7): Document that in some circumstances *note
     KeyboardInterrupt: 9dc. may cause the code to enter an inconsistent
     state.  Provided a sample workaround to avoid it if needed.

   - bpo-41233(8): Link the errnos referenced in
     ‘Doc/library/exceptions.rst’ to their respective section in
     ‘Doc/library/errno.rst’, and vice versa.  Previously this was only
     done for EINTR and InterruptedError.  Patch by Yan “yyyyyyyan”
     Orestes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45099

   (2) https://bugs.python.org/issue?@action=redirect&bpo=47126

   (3) https://peps.python.org/pep-0676/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47040

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46033

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45790

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42340

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41233


File: python.info,  Node: Tests<31>,  Next: Build<34>,  Prev: Documentation<28>,  Up: Python 3 11 0 alpha 7

1.23.37.8 Tests
...............

   - bpo-47205(1): Skip test for *note sched_getaffinity(): 114e. and
     *note sched_setaffinity(): 1152. error case on FreeBSD.

   - bpo-46126(2): Restore ‘descriptions’ when running tests internally.

   - bpo-47104(3): Rewrite *note asyncio.to_thread(): 8f1. tests to use
     *note unittest.IsolatedAsyncioTestCase: 30c.

   - bpo-40280(4): The test suite is now passing on the Emscripten
     platform.  All fork, socket, and subprocess-based tests are
     skipped.

   - bpo-47037(5): Skip ‘strftime("%4Y")’ feature test on Windows.  It
     can cause an assertion error in debug builds.

   - bpo-46587(6): Skip tests if platform’s ‘strftime’ does not support
     non-portable glibc extensions.

   - bpo-47015(7): A test case for *note os.sendfile(): b28. is
     converted from deprecated ‘asyncore’ (see PEP 594(8)) to *note
     asyncio: a.  Patch by Oleg Iarygin.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47205

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46126

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47104

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (5) https://bugs.python.org/issue?@action=redirect&bpo=47037

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46587

   (7) https://bugs.python.org/issue?@action=redirect&bpo=47015

   (8) https://peps.python.org/pep-0594/


File: python.info,  Node: Build<34>,  Next: Windows<29>,  Prev: Tests<31>,  Up: Python 3 11 0 alpha 7

1.23.37.9 Build
...............

   - bpo-40280(1): Add configure option *note
     -enable-wasm-dynamic-linking: 1963. to enable ‘dlopen’ and
     MAIN_MODULE / SIDE_MODULE on ‘wasm32-emscripten’.

   - bpo-46023(2): ‘makesetup’ now detects and skips all duplicated
     module definitions.  The first entry wins.

   - bpo-40280(3): Add SOABI ‘wasm32-emscripten’ for Emscripten and
     ‘wasm32-wasi’ for WASI on 32bit WASM as well as ‘wasm64’ counter
     parts.

   - bpo-47032(4): Ensure Windows install builds fail correctly with a
     non-zero exit code when part of the build fails.

   - bpo-47024(5): Update OpenSSL to 1.1.1n for macOS installers and all
     Windows builds.

   - bpo-46996(6): The *note tkinter: f0. package now requires Tcl/Tk
     version 8.5.12 or newer.

   - bpo-46973(7): Add ‘regen-configure’ make target to regenerate
     configure script with Christian’s container image
     ‘quay.io/tiran/cpython_autoconf:269’.

   - bpo-46917(8): Building Python now requires support of IEEE 754
     floating-point numbers.  Patch by Victor Stinner.

   - bpo-45774(9): ‘configure’ now verifies that all SQLite C APIs
     needed for the *note sqlite3: cf. extension module are found.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46023

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (4) https://bugs.python.org/issue?@action=redirect&bpo=47032

   (5) https://bugs.python.org/issue?@action=redirect&bpo=47024

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46996

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46973

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46917

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45774


File: python.info,  Node: Windows<29>,  Next: macOS<22>,  Prev: Build<34>,  Up: Python 3 11 0 alpha 7

1.23.37.10 Windows
..................

   - bpo-47194(1): Update ‘zlib’ to v1.2.12 to resolve CVE
     2018-25032(2).

   - bpo-47171(3): Enables installing the ‘py.exe’ launcher on Windows
     ARM64.

   - bpo-46566(4): Upgraded *note Python Launcher for Windows: 5c1. to
     support a new ‘-V:company/tag’ argument for full PEP 514(5) support
     and to detect ARM64 installs.  The ‘-64’ suffix on arguments is
     deprecated, but still selects any non-32-bit install.  Setting
     ‘PYLAUNCHER_ALLOW_INSTALL’ and specifying a version that is not
     installed will attempt to install the requested version from the
     Microsoft Store.

   - bpo-47086(6): The installer for Windows now includes documentation
     as loose HTML files rather than a single compiled ‘.chm’ file.

   - bpo-46907(7): Update Windows installer to use SQLite 3.38.1.

   - bpo-44549(8): Update bzip2 to 1.0.8 in Windows builds to mitigate
     CVE 2016-3189(9) and CVE 2019-12900(10).

   - bpo-46948(11): Prevent CVE 2022-26488(12) by ensuring the Add to
     PATH option in the Windows installer uses the correct path when
     being repaired.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=47194

   (2) https://www.cve.org/CVERecord?id=CVE-2018-25032

   (3) https://bugs.python.org/issue?@action=redirect&bpo=47171

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46566

   (5) https://peps.python.org/pep-0514/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=47086

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46907

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44549

   (9) https://www.cve.org/CVERecord?id=CVE-2016-3189

   (10) https://www.cve.org/CVERecord?id=CVE-2019-12900

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46948

   (12) https://www.cve.org/CVERecord?id=CVE-2022-26488


File: python.info,  Node: macOS<22>,  Next: Tools/Demos<19>,  Prev: Windows<29>,  Up: Python 3 11 0 alpha 7

1.23.37.11 macOS
................

   - bpo-46890(1): Fix a regression in the setting of
     ‘sys._base_executable’ in framework builds, and thereby fix a
     regression in *note venv: 111. virtual environments with such
     builds.

   - bpo-46907(2): Update macOS installer to SQLite 3.38.1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46890

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46907


File: python.info,  Node: Tools/Demos<19>,  Next: C API<30>,  Prev: macOS<22>,  Up: Python 3 11 0 alpha 7

1.23.37.12 Tools/Demos
......................

   - bpo-40280(1): Replace Emscripten’s limited shell with Katie Bell’s
     browser-ui REPL from python-wasm project.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40280


File: python.info,  Node: C API<30>,  Prev: Tools/Demos<19>,  Up: Python 3 11 0 alpha 7

1.23.37.13 C API
................

   - bpo-40421(1): Add ‘PyFrame_GetBuiltins’, ‘PyFrame_GetGenerator’ and
     ‘PyFrame_GetGlobals’ C-API functions to access frame object
     attributes safely from C code.

   - bpo-46850(2): Move the private ‘_PyFrameEvalFunction’ type, and
     private ‘_PyInterpreterState_GetEvalFrameFunc()’ and
     ‘_PyInterpreterState_SetEvalFrameFunc()’ functions to the internal
     C API. The ‘_PyFrameEvalFunction’ callback function type now uses
     the ‘_PyInterpreterFrame’ type which is part of the internal C API.
     Patch by Victor Stinner.

   - bpo-46850(3): Move the private undocumented
     ‘_PyEval_EvalFrameDefault()’ function to the internal C API. The
     function now uses the ‘_PyInterpreterFrame’ type which is part of
     the internal C API. Patch by Victor Stinner.

   - bpo-46850(4): Remove the private undocumented function
     ‘_PyEval_CallTracing()’ from the C API. Call the public *note
     sys.call_tracing(): 1968. function instead.  Patch by Victor
     Stinner.

   - bpo-46850(5): Remove the private undocumented function
     ‘_PyEval_GetCoroutineOriginTrackingDepth()’ from the C API. Call
     the public *note sys.get_coroutine_origin_tracking_depth(): ba9.
     function instead.  Patch by Victor Stinner.

   - bpo-46850(6): Remove the following private undocumented functions
     from the C API:

        * ‘_PyEval_GetAsyncGenFirstiter()’

        * ‘_PyEval_GetAsyncGenFinalizer()’

        * ‘_PyEval_SetAsyncGenFirstiter()’

        * ‘_PyEval_SetAsyncGenFinalizer()’

     Call the public *note sys.get_asyncgen_hooks(): 1969. and *note
     sys.set_asyncgen_hooks(): 1730. functions instead.  Patch by Victor
     Stinner.

   - bpo-46987(7): Remove private functions ‘_PySys_GetObjectId()’ and
     ‘_PySys_SetObjectId()’.  Patch by Donghee Na.

   - bpo-46906(8): Add new functions to pack and unpack C double
     (serialize and deserialize): *note PyFloat_Pack2(): 768, *note
     PyFloat_Pack4(): 769, *note PyFloat_Pack8(): 76a, *note
     PyFloat_Unpack2(): 76b, *note PyFloat_Unpack4(): 76c. and *note
     PyFloat_Unpack8(): 76d.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46850

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46850

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46850

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46850

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46850

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46987

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46906


File: python.info,  Node: Python 3 11 0 alpha 6,  Next: Python 3 11 0 alpha 5,  Prev: Python 3 11 0 alpha 7,  Up: Changelog

1.23.38 Python 3.11.0 alpha 6
-----------------------------

'Release date: 2022-03-07'

* Menu:

* Core and Builtins: Core and Builtins<67>.
* Library: Library<69>.
* Core and Builtins: Core and Builtins<68>.
* Library: Library<70>.
* Core and Builtins: Core and Builtins<69>.
* Library: Library<71>.
* Core and Builtins: Core and Builtins<70>.
* Library: Library<72>.
* Documentation: Documentation<29>.
* Tests: Tests<32>.
* Build: Build<35>.
* Windows: Windows<30>.
* IDLE: IDLE<20>.
* C API: C API<31>.


File: python.info,  Node: Core and Builtins<67>,  Next: Library<69>,  Up: Python 3 11 0 alpha 6

1.23.38.1 Core and Builtins
...........................

   - bpo-46940(1): Avoid overriding *note AttributeError: 34e. metadata
     information for nested attribute access calls.  Patch by Pablo
     Galindo.

   - bpo-46927(2): Include the type’s name in the error message for
     subscripting non-generic types.

   - bpo-46921(3): Support vectorcall for ‘super()’.  Patch by Ken Jin.

   - bpo-46841(4): Fix incorrect handling of inline cache entries when
     specializing *note BINARY_OP: 709.

   - bpo-46841(5): Use an oparg to simplify the construction of helpful
     error messages in *note GET_AWAITABLE: 196c.

   - bpo-46903(6): Make sure that str subclasses can be used as
     attribute names for instances with virtual dictionaries.  Fixes
     regression in 3.11alpha

   - bpo-46841(7): Add more detailed specialization failure stats for
     *note COMPARE_OP: 973. followed by *note EXTENDED_ARG: 18c1.

   - bpo-46891(8): Fix bug introduced during 3.11alpha where subclasses
     of ‘types.ModuleType’ with ‘__slots__’ were not initialized
     correctly, resulting in an interpreter crash.

   - bpo-46841(9): Use inline caching for *note LOAD_ATTR: 4e1, *note
     LOAD_METHOD: c3f, and *note STORE_ATTR: 196d.

   - bpo-46841(10): Use inline cache for *note BINARY_SUBSCR: 1851.

   - bpo-46841(11): Use inline caching for *note COMPARE_OP: 973.

   - bpo-46864(12): Deprecate ‘PyBytesObject.ob_shash’.  It will be
     removed in Python 3.13.

   - bpo-46841(13): Use inline caching for *note UNPACK_SEQUENCE: 196e.

   - bpo-46845(14): Reduces dict size by removing hash value from hash
     table when all inserted keys are Unicode.  For example,
     ‘sys.getsizeof(dict.fromkeys("abcdefg"))’ becomes 272 bytes from
     352 bytes on 64bit platform.

   - bpo-46841(15): Use inline cache for *note LOAD_GLOBAL: 17f9.

   - bpo-46852(16): Rename the private undocumented
     ‘float.__set_format__()’ method to ‘float.__setformat__()’ to fix a
     typo introduced in Python 3.7.  The method is only used by
     test_float.  Patch by Victor Stinner.

   - bpo-46852(17): Remove the undocumented private
     ‘float.__set_format__()’ method, previously known as
     ‘float.__setformat__()’ in Python 3.7.  Its docstring said: “You
     probably don’t want to use this function.  It exists mainly to be
     used in Python’s test suite.” Patch by Victor Stinner.

   - bpo-40116(18): Fix regression that dict.update(other) may don’t
     respect iterate order of other when other is key sharing dict.

   - bpo-46712(19): Share global string identifiers in deep-frozen
     modules.

   - bpo-46430(20): Fix memory leak in interned strings of deep-frozen
     modules.

   - bpo-46841(21): Store *note BINARY_OP: 709. caches inline using a
     new *note CACHE: 6fc. instruction.

   - bpo-45107(22): Specialize ‘LOAD_METHOD’ for instances with a dict.

   - bpo-44337(23): Reduce the memory usage of specialized *note
     LOAD_ATTR: 4e1. and *note STORE_ATTR: 196d. instructions.

   - bpo-46729(24): Add number of sub-exceptions to
     ‘BaseException.__str__()’.

   - bpo-45885(25): Don’t un-adapt *note COMPARE_OP: 973. when
     collecting specialization stats.

   - bpo-46329(26): Fix specialization stats gathering for ‘PRECALL’
     instructions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46940

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46927

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46921

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46903

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46891

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (12) https://bugs.python.org/issue?@action=redirect&bpo=46864

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (14) https://bugs.python.org/issue?@action=redirect&bpo=46845

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (16) https://bugs.python.org/issue?@action=redirect&bpo=46852

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46852

   (18) https://bugs.python.org/issue?@action=redirect&bpo=40116

   (19) https://bugs.python.org/issue?@action=redirect&bpo=46712

   (20) https://bugs.python.org/issue?@action=redirect&bpo=46430

   (21) https://bugs.python.org/issue?@action=redirect&bpo=46841

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45107

   (23) https://bugs.python.org/issue?@action=redirect&bpo=44337

   (24) https://bugs.python.org/issue?@action=redirect&bpo=46729

   (25) https://bugs.python.org/issue?@action=redirect&bpo=45885

   (26) https://bugs.python.org/issue?@action=redirect&bpo=46329


File: python.info,  Node: Library<69>,  Next: Core and Builtins<68>,  Prev: Core and Builtins<67>,  Up: Python 3 11 0 alpha 6

1.23.38.2 Library
.................

   - bpo-46794(1): Bump up the libexpat version into 2.4.6

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46794


File: python.info,  Node: Core and Builtins<68>,  Next: Library<70>,  Prev: Library<69>,  Up: Python 3 11 0 alpha 6

1.23.38.3 Core and Builtins
...........................

   - bpo-46823(1): Implement a specialized combined opcode
     ‘LOAD_FAST__LOAD_ATTR_INSTANCE_VALUE’.  Patch by Dennis Sweeney.

   - bpo-46820(2): Fix parsing a numeric literal immediately (without
     spaces) followed by “not in” keywords, like in ‘1not in x’.  Now
     the parser only emits a warning, not a syntax error.

   - bpo-46329(3): Move ‘KW_NAMES’ before ‘PRECALL’ instruction in call
     sequence.  Change ‘operand’ of ‘CALL’ to match ‘PRECALL’ for easier
     specialization.

   - bpo-46808(4): Remove the ‘NEXT_BLOCK’ macro from compile.c, and
     make the compiler automatically generate implicit blocks when they
     are needed.

   - bpo-46329(5): Add ‘PUSH_NULL’ instruction.  This is used as a
     prefix when evaluating a callable, so that the stack has the same
     shape for methods and other calls.  ‘PRECALL_FUNCTION’ and
     ‘PRECALL_METHOD’ are merged into a single ‘PRECALL’ instruction.

     There is no change in semantics.

   - bpo-46762(6): Fix an assert failure in debug builds when a ‘<’,
     ‘>’, or ‘=’ is the last character in an f-string that’s missing a
     closing right brace.

   - bpo-46730(7): Message of AttributeError caused by getting, setting
     or deleting a property without the corresponding function now
     mentions that the attribute is in fact a property and also
     specifies type of the class that it belongs to.

   - bpo-46724(8): Make sure that all backwards jumps use the
     ‘JUMP_ABSOLUTE’ instruction, rather than ‘JUMP_FORWARD’ with an
     argument of ‘(2**32)+offset’.

   - bpo-46732(9): Correct the docstring for the *note __bool__(): 131d.
     method.  Patch by Jelle Zijlstra.

   - bpo-46072(10): Add more detailed specialization failure statistics
     for *note BINARY_OP: 709.

   - bpo-46707(11): Avoid potential exponential backtracking when
     producing some syntax errors involving lots of brackets.  Patch by
     Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46823

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46820

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46329

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46808

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46329

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46762

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46730

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46724

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46732

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46072

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46707


File: python.info,  Node: Library<70>,  Next: Core and Builtins<69>,  Prev: Core and Builtins<68>,  Up: Python 3 11 0 alpha 6

1.23.38.4 Library
.................

   - bpo-46323(1): *note ctypes: 2a. now allocates memory on the stack
     instead of on the heap to pass arguments while calling a Python
     callback function.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46323


File: python.info,  Node: Core and Builtins<69>,  Next: Library<71>,  Prev: Library<70>,  Up: Python 3 11 0 alpha 6

1.23.38.5 Core and Builtins
...........................

   - bpo-45923(1): Add a quickened form of *note RESUME: 315. that skips
     quickening checks.

   - bpo-46702(2): Specialize *note UNPACK_SEQUENCE: 196e. for *note
     tuple: 373. and *note list: 614. unpackings.

   - bpo-46072(3): Opcode pair stats are now gathered with
     ‘--enable-pystats’.  Defining ‘DYNAMIC_EXECUTION_PROFILE’ or
     ‘DXPAIRS’ no longer has any effect.

   - bpo-46675(4): Allow more than 16 items in a split dict before it is
     combined.  The limit is now 254.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45923

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46702

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46072

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46675


File: python.info,  Node: Library<71>,  Next: Core and Builtins<70>,  Prev: Core and Builtins<69>,  Up: Python 3 11 0 alpha 6

1.23.38.6 Library
.................

   - bpo-40479(1): Add a missing call to ‘va_end()’ in
     ‘Modules/_hashopenssl.c’.

   - bpo-46323(2): Use *note PyObject_Vectorcall(): 55f. while calling
     ctypes callback function.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40479

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46323


File: python.info,  Node: Core and Builtins<70>,  Next: Library<72>,  Prev: Library<71>,  Up: Python 3 11 0 alpha 6

1.23.38.7 Core and Builtins
...........................

   - bpo-46615(1): When iterating over sets internally in ‘setobject.c’,
     acquire strong references to the resulting items from the set.
     This prevents crashes in corner-cases of various set operations
     where the set gets mutated.

   - bpo-45828(2): The bytecode compiler now attempts to apply runtime
     stack manipulations at compile-time (whenever it is feasible to do
     so).

   - bpo-30496(3): Fixed a minor portability issue in the implementation
     of *note PyLong_FromLong(): 1975, and added a fast path for
     single-digit integers to *note PyLong_FromLongLong(): 1976.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46615

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45828

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30496


File: python.info,  Node: Library<72>,  Next: Documentation<29>,  Prev: Core and Builtins<70>,  Up: Python 3 11 0 alpha 6

1.23.38.8 Library
.................

   - bpo-25707(1): Fixed a file leak in *note
     xml.etree.ElementTree.iterparse(): 273. when the iterator is not
     exhausted.  Patch by Jacob Walls.

   - bpo-46877(2): Export *note unittest.doModuleCleanups(): 1978. in
     *note unittest: 106.  Patch by Kumar Aditya.

   - bpo-46848(3): For performance, use the optimized string-searching
     implementations from *note find(): 1979. and *note rfind(): 197a.
     for ‘find()’ and ‘rfind()’.

   - bpo-46736(4): *note SimpleHTTPRequestHandler: b5c. now uses HTML5
     grammar.  Patch by Donghee Na.

   - bpo-44886(5): Inherit asyncio proactor datagram transport from
     *note asyncio.DatagramTransport: 18ca.

   - bpo-46827(6): Support UDP sockets in *note
     asyncio.loop.sock_connect(): df8. for selector-based event loops.
     Patch by Thomas Grainger.

   - bpo-46811(7): Make test suite support Expat >=2.4.5

   - bpo-46252(8): Raise *note TypeError: 2c3. if *note ssl.SSLSocket:
     8f3. is passed to transport-based APIs.

   - bpo-46784(9): Fix libexpat symbols collisions with user dynamically
     loaded or statically linked libexpat in embedded Python.

   - bpo-46786(10): The HTML serialisation in xml.etree.ElementTree now
     writes ‘embed’, ‘source’, ‘track’ and ‘wbr’ as empty tags, as
     defined in HTML 5.

   - bpo-39327(11): *note shutil.rmtree(): 301. can now work with
     VirtualBox shared folders when running from the guest
     operating-system.

   - bpo-45390(12): Propagate *note asyncio.CancelledError: 1b8. message
     from inner task to outer awaiter.

   - bpo-46756(13): Fix a bug in *note
     urllib.request.HTTPPasswordMgr.find_user_password(): 197b. and
     *note
     urllib.request.HTTPPasswordMgrWithPriorAuth.is_authenticated():
     197c. which allowed to bypass authorization.  For example, access
     to URI ‘example.org/foobar’ was allowed if the user was authorized
     for URI ‘example.org/foo’.

   - bpo-46737(14): *note random.gauss(): 197d. and *note
     random.normalvariate(): 197e. now have default arguments.

   - bpo-46752(15): Add task groups to asyncio (structured concurrency,
     inspired by Trio’s nurseries).  This also introduces a change to
     task cancellation, where a cancelled task can’t be cancelled again
     until it calls .uncancel().

   - bpo-46724(16): Fix *note dis: 38. behavior on negative jump
     offsets.

   - bpo-46333(17): The ‘__repr__()’ method of *note typing.ForwardRef:
     197f. now includes the ‘module’ parameter of ‘typing.ForwardRef’
     when it is set.

   - bpo-46643(18): In *note typing.get_type_hints(): 6b4, support
     evaluating stringified ‘ParamSpecArgs’ and ‘ParamSpecKwargs’
     annotations.  Patch by Gregory Beauregard.

   - bpo-45863(19): When the *note tarfile: de. module creates a pax
     format archive, it will put an integer representation of timestamps
     in the ustar header (if possible) for the benefit of older
     unarchivers, in addition to the existing full-precision timestamps
     in the pax extended header.

   - bpo-46066(20): Deprecate kwargs-based syntax for *note
     typing.TypedDict: 162. definitions.  It had confusing semantics
     when specifying totality, and was largely unused.  Patch by
     Jingchen Ye.

   - bpo-46676(21): Make *note typing.ParamSpec: 15e. args and kwargs
     equal to themselves.  Patch by Gregory Beauregard.

   - bpo-46323(22): ‘ctypes.CFUNCTYPE()’ and ‘ctypes.WINFUNCTYPE()’ now
     fail to create the type if its ‘_argtypes_’ member contains too
     many arguments.  Previously, the error was only raised when calling
     a function.  Patch by Victor Stinner.

   - bpo-46672(23): Fix ‘NameError’ in *note asyncio.gather(): 600. when
     initial type check fails.

   - bpo-46659(24): The *note calendar.LocaleTextCalendar: 747. and
     *note calendar.LocaleHTMLCalendar: 748. classes now use *note
     locale.getlocale(): 2da, instead of using *note
     locale.getdefaultlocale(): 2d9, if no locale is specified.  Patch
     by Victor Stinner.

   - bpo-46659(25): The *note locale.getdefaultlocale(): 2d9. function
     is deprecated and will be removed in Python 3.13.  Use *note
     locale.setlocale(): 2db, *note locale.getpreferredencoding(False):
     53d. and *note locale.getlocale(): 2da. functions instead.  Patch
     by Victor Stinner.

   - bpo-46655(26): In *note typing.get_type_hints(): 6b4, support
     evaluating bare stringified ‘TypeAlias’ annotations.  Patch by
     Gregory Beauregard.

   - bpo-45948(27): Fixed a discrepancy in the C implementation of the
     *note xml.etree.ElementTree: 125. module.  Now, instantiating an
     *note xml.etree.ElementTree.XMLParser: a62. with a ‘target=None’
     keyword provides a default *note xml.etree.ElementTree.TreeBuilder:
     a63. target as the Python implementation does.

   - bpo-46626(28): Expose Linux’s ‘IP_BIND_ADDRESS_NO_PORT’ option in
     *note socket: cc.

   - bpo-46521(29): Fix a bug in the *note codeop: 1c. module that was
     incorrectly identifying invalid code involving string quotes as
     valid code.

   - bpo-46571(30): Improve *note typing.no_type_check(): 6b7.

     Now it does not modify external classes and functions.  We also now
     correctly mark classmethods as not to be type checked.

   - bpo-46400(31): expat: Update libexpat from 2.4.1 to 2.4.4

   - bpo-46556(32): Deprecate undocumented support for using a *note
     pathlib.Path: 229. object as a context manager.

   - bpo-46534(33): Implement PEP 673(34) *note typing.Self: 5ca.  Patch
     by James Hilton-Balfe.

   - bpo-46522(35): Make various module ‘__getattr__’ AttributeErrors
     more closely match a typical AttributeError

   - bpo-46475(36): Add *note typing.Never: 6ab. and *note
     typing.assert_never(): 6aa.  Patch by Jelle Zijlstra.

   - bpo-46333(37): The ‘__eq__()’ and ‘__hash__()’ methods of *note
     typing.ForwardRef: 197f. now honor the ‘module’ parameter of
     ‘typing.ForwardRef’.  Forward references from different modules are
     now differentiated.

   - bpo-46246(38): Add missing ‘__slots__’ to
     ‘importlib.metadata.DeprecatedList’.  Patch by Arie Bovenberg.

   - bpo-46232(39): The *note ssl: d0. module now handles certificates
     with bit strings in DN correctly.

   - bpo-46195(40): *note typing.get_type_hints(): 6b4. no longer adds
     ‘Optional’ to parameters with ‘None’ as a default.  This aligns to
     changes to PEP 484 in ‘https://github.com/python/peps/pull/689’

   - bpo-31369(41): Add *note RegexFlag: 630. to ‘re.__all__’ and
     documented it.  Add ‘NOFLAG’ to indicate no flags being set.

   - bpo-45898(42): *note ctypes: 2a. no longer defines ‘ffi_type_*’
     symbols in ‘cfield.c’.  The symbols have been provided by libffi
     for over a decade.

   - bpo-44953(43): Calling ‘operator.itemgetter’ objects and
     ‘operator.attrgetter’ objects is now faster due to use of the
     vectorcall calling convention.

   - bpo-44289(44): Fix an issue with *note is_tarfile(): 1980. method
     when using 'fileobj' argument: position in the 'fileobj' was
     advanced forward which made it unreadable with *note
     tarfile.TarFile.open(): 1981.

   - bpo-44011(45): Reimplement SSL/TLS support in asyncio, borrow the
     implementation from uvloop library.

   - bpo-41086(46): Make the *note configparser.ConfigParser: 1c8.
     constructor raise *note TypeError: 2c3. if the ‘interpolation’
     parameter is not of type ‘configparser.Interpolation’

   - bpo-29418(47): Implement *note inspect.ismethodwrapper(): 64d. and
     fix *note inspect.isroutine(): 16f4. for cases where methodwrapper
     is given.  Patch by Hakan Çelik.

   - bpo-14156(48): argparse.FileType now supports an argument of ‘-’ in
     binary mode, returning the .buffer attribute of
     sys.stdin/sys.stdout as appropriate.  Modes including ‘x’ and ‘a’
     are treated equivalently to ‘w’ when argument is ‘-’.  Patch
     contributed by Josh Rosenberg

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25707

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46877

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46848

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46736

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44886

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46827

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46811

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46252

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46784

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46786

   (11) https://bugs.python.org/issue?@action=redirect&bpo=39327

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45390

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46756

   (14) https://bugs.python.org/issue?@action=redirect&bpo=46737

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46752

   (16) https://bugs.python.org/issue?@action=redirect&bpo=46724

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46333

   (18) https://bugs.python.org/issue?@action=redirect&bpo=46643

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45863

   (20) https://bugs.python.org/issue?@action=redirect&bpo=46066

   (21) https://bugs.python.org/issue?@action=redirect&bpo=46676

   (22) https://bugs.python.org/issue?@action=redirect&bpo=46323

   (23) https://bugs.python.org/issue?@action=redirect&bpo=46672

   (24) https://bugs.python.org/issue?@action=redirect&bpo=46659

   (25) https://bugs.python.org/issue?@action=redirect&bpo=46659

   (26) https://bugs.python.org/issue?@action=redirect&bpo=46655

   (27) https://bugs.python.org/issue?@action=redirect&bpo=45948

   (28) https://bugs.python.org/issue?@action=redirect&bpo=46626

   (29) https://bugs.python.org/issue?@action=redirect&bpo=46521

   (30) https://bugs.python.org/issue?@action=redirect&bpo=46571

   (31) https://bugs.python.org/issue?@action=redirect&bpo=46400

   (32) https://bugs.python.org/issue?@action=redirect&bpo=46556

   (33) https://bugs.python.org/issue?@action=redirect&bpo=46534

   (34) https://peps.python.org/pep-0673/

   (35) https://bugs.python.org/issue?@action=redirect&bpo=46522

   (36) https://bugs.python.org/issue?@action=redirect&bpo=46475

   (37) https://bugs.python.org/issue?@action=redirect&bpo=46333

   (38) https://bugs.python.org/issue?@action=redirect&bpo=46246

   (39) https://bugs.python.org/issue?@action=redirect&bpo=46232

   (40) https://bugs.python.org/issue?@action=redirect&bpo=46195

   (41) https://bugs.python.org/issue?@action=redirect&bpo=31369

   (42) https://bugs.python.org/issue?@action=redirect&bpo=45898

   (43) https://bugs.python.org/issue?@action=redirect&bpo=44953

   (44) https://bugs.python.org/issue?@action=redirect&bpo=44289

   (45) https://bugs.python.org/issue?@action=redirect&bpo=44011

   (46) https://bugs.python.org/issue?@action=redirect&bpo=41086

   (47) https://bugs.python.org/issue?@action=redirect&bpo=29418

   (48) https://bugs.python.org/issue?@action=redirect&bpo=14156


File: python.info,  Node: Documentation<29>,  Next: Tests<32>,  Prev: Library<72>,  Up: Python 3 11 0 alpha 6

1.23.38.9 Documentation
.......................

   - bpo-42238(1): ‘Doc/tools/rstlint.py’ has moved to its own
     repository and is now packaged on PyPI as ‘sphinx-lint’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42238


File: python.info,  Node: Tests<32>,  Next: Build<35>,  Prev: Documentation<29>,  Up: Python 3 11 0 alpha 6

1.23.38.10 Tests
................

   - bpo-46913(1): Fix test_faulthandler.test_sigfpe() if Python is
     built with undefined behavior sanitizer (UBSAN): disable UBSAN on
     the faulthandler_sigfpe() function.  Patch by Victor Stinner.

   - bpo-46760(2): Remove bytecode offsets from expected values in
     test.test_dis module.  Reduces the obstacles to modifying the VM or
     compiler.

   - bpo-46708(3): Prevent default asyncio event loop policy
     modification warning after ‘test_asyncio’ execution.

   - bpo-46678(4): The function ‘make_legacy_pyc’ in
     ‘Lib/test/support/import_helper.py’ no longer fails when
     ‘PYTHONPYCACHEPREFIX’ is set to a directory on a different device
     from where tempfiles are stored.

   - bpo-46623(5): Skip test_pair() and test_speech128() of test_zlib on
     s390x since they fail if zlib uses the s390x hardware accelerator.
     Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46913

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46760

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46708

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46678

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46623


File: python.info,  Node: Build<35>,  Next: Windows<30>,  Prev: Tests<32>,  Up: Python 3 11 0 alpha 6

1.23.38.11 Build
................

   - bpo-46860(1): Respect ‘--with-suffix’ when building on
     case-insensitive file systems.

   - bpo-46656(2): Building Python now requires a C11 compiler.
     Optional C11 features are not required.  Patch by Victor Stinner.

   - bpo-46656(3): Building Python now requires support for
     floating-point Not-a-Number (NaN): remove the ‘Py_NO_NAN’ macro.
     Patch by Victor Stinner.

   - bpo-46640(4): Building Python now requires a C99 ‘<math.h>’ header
     file providing a ‘NAN’ constant, or the ‘__builtin_nan()’ built-in
     function.  Patch by Victor Stinner.

   - bpo-46608(5): Exclude marshalled-frozen data if deep-freezing to
     save 300 KB disk space.  This includes adding a new ‘is_package’
     field to *note _frozen: 778.  Patch by Kumar Aditya.

   - bpo-40280(6): Fix wasm32-emscripten test failures and platform
     issues.  - Disable syscalls that are not supported or don’t work,
     e.g.  wait, getrusage, prlimit, mkfifo, mknod, setres[gu]id,
     setgroups.  - Use fd_count to count open fds.  - Add more checks
     for subprocess and fork.  - Add workarounds for missing
     _multiprocessing and failing socket.accept().  - Enable bzip2.  -
     Disable large file support.  - Disable signal.alarm.

   - bpo-46430(7): Intern strings in deep-frozen modules.  Patch by
     Kumar Aditya.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46860

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46656

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46656

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46640

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46608

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46430


File: python.info,  Node: Windows<30>,  Next: IDLE<20>,  Prev: Build<35>,  Up: Python 3 11 0 alpha 6

1.23.38.12 Windows
..................

   - bpo-46744(1): The default all users install directory for ARM64 is
     now under the native ‘Program Files’ folder, rather than ‘Program
     Files (Arm)’ which is intended for ARM (32-bit) files.

   - bpo-46567(2): Adds Tcl and Tk support for Windows ARM64.  This also
     adds IDLE to the installation.

   - bpo-46638(3): Ensures registry virtualization is consistently
     disabled.  For 3.10 and earlier, it remains enabled (some registry
     writes are protected), while for 3.11 and later it is disabled
     (registry modifications affect all applications).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46744

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46567

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46638


File: python.info,  Node: IDLE<20>,  Next: C API<31>,  Prev: Windows<30>,  Up: Python 3 11 0 alpha 6

1.23.38.13 IDLE
...............

   - bpo-46630(1): Make query dialogs on Windows start with a cursor in
     the entry box.

   - bpo-45447(2): Apply IDLE syntax highlighting to ‘.pyi’ files.
     Patch by Alex Waygood and Terry Jan Reedy.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46630

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45447


File: python.info,  Node: C API<31>,  Prev: IDLE<20>,  Up: Python 3 11 0 alpha 6

1.23.38.14 C API
................

   - bpo-46748(1): Python’s public headers no longer import
     ‘<stdbool.h>’, leaving code that embeds/extends Python free to
     define ‘bool’, ‘true’ and ‘false’.

   - bpo-46836(2): Move the *note PyFrameObject: 78c. type definition
     (‘struct _frame’) to the internal C API ‘pycore_frame.h’ header
     file.  Patch by Victor Stinner.

   - bpo-45459(3): Rename ‘Include/buffer.h’ header file to
     ‘Include/pybuffer.h’ to avoid conflicts with projects having an
     existing ‘buffer.h’ header file.  Patch by Victor Stinner.

   - bpo-45412(4): Remove the ‘HAVE_PY_SET_53BIT_PRECISION’ macro (moved
     to the internal C API). Patch by Victor Stinner.

   - bpo-46613(5): Added function *note PyType_GetModuleByDef(): 397,
     which allows access to module state when a method’s defining class
     is not available.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46748

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46836

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45459

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45412

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46613


File: python.info,  Node: Python 3 11 0 alpha 5,  Next: Python 3 11 0 alpha 4,  Prev: Python 3 11 0 alpha 6,  Up: Changelog

1.23.39 Python 3.11.0 alpha 5
-----------------------------

'Release date: 2022-02-03'

* Menu:

* Core and Builtins: Core and Builtins<71>.
* Library: Library<73>.
* Core and Builtins: Core and Builtins<72>.
* Library: Library<74>.
* Build: Build<36>.
* Core and Builtins: Core and Builtins<73>.
* Library: Library<75>.
* Documentation: Documentation<30>.
* Tests: Tests<33>.
* Build: Build<37>.
* Windows: Windows<31>.
* macOS: macOS<23>.
* IDLE: IDLE<21>.
* C API: C API<32>.


File: python.info,  Node: Core and Builtins<71>,  Next: Library<73>,  Up: Python 3 11 0 alpha 5

1.23.39.1 Core and Builtins
...........................

   - bpo-45773(1): Remove two invalid “peephole” optimizations from the
     bytecode compiler.

   - bpo-46564(2): Do not create frame objects when creating *note
     super: 4de. object.  Patch by Kumar Aditya.

   - bpo-45885(3): Added more fined-grained specialization failure stats
     regarding the ‘COMPARE_OP’ bytecode.

   - bpo-44977(4): The delegation of *note int(): 257. to ‘__trunc__()’
     is now deprecated.  Calling ‘int(a)’ when ‘type(a)’ implements
     ‘__trunc__()’ but not ‘__int__()’ or ‘__index__()’ now raises a
     *note DeprecationWarning: 1a5.

   - bpo-46458(5): Reorder code emitted by the compiler for a *note try:
     6ec.-*note except: 18b. block so that the *note else: 18c. block’s
     code immediately follows the ‘try’ body (without a jump).  This is
     more optimal for the happy path.

   - bpo-46527(6): Allow passing ‘iterable’ as a keyword argument to
     *note enumerate(): 14d0. again.  Patch by Jelle Zijlstra.

   - bpo-46528(7): Replace several stack manipulation instructions
     (‘DUP_TOP’, ‘DUP_TOP_TWO’, ‘ROT_TWO’, ‘ROT_THREE’, ‘ROT_FOUR’, and
     ‘ROT_N’) with new *note COPY: 70c. and *note SWAP: 70d.
     instructions.

   - bpo-46329(8): Use two or three bytecodes to implement most calls.

     Calls without named arguments are implemented as a sequence of two
     instructions: ‘PRECALL; CALL’.  Calls with named arguments are
     implemented as a sequence of three instructions: ‘PRECALL;
     KW_NAMES; CALL’.  There are two different ‘PRECALL’ instructions:
     ‘PRECALL_FUNTION’ and ‘PRECALL_METHOD’.  The latter pairs with
     ‘LOAD_METHOD’.

     This partition into pre-call and call allows better specialization,
     and thus better performance ultimately.

     There is no change in semantics.

   - bpo-46503(9): Fix an assert when parsing some invalid N escape
     sequences in f-strings.

   - bpo-46431(10): Improve error message on invalid calls to
     ‘BaseExceptionGroup.__new__()’.

   - bpo-46476(11): Fix memory leak in code objects generated by
     deepfreeze.  Patch by Kumar Aditya.

   - bpo-46481(12): Speed up calls to ‘weakref.ref.__call__()’ by using
     the PEP 590(13) ‘vectorcall’ calling convention.  Patch by Donghee
     Na.

   - bpo-46417(14): Fix a race condition on setting a type ‘__bases__’
     attribute: the internal function ‘add_subclass()’ now gets the
     ‘PyTypeObject.tp_subclasses’ member after calling *note
     PyWeakref_NewRef(): 198a. which can trigger a garbage collection
     which can indirectly modify ‘PyTypeObject.tp_subclasses’.  Patch by
     Victor Stinner.

   - bpo-46417(15): ‘python -X showrefcount’ now shows the total
     reference count after clearing and destroyed the main Python
     interpreter.  Previously, it was shown before.  Patch by Victor
     Stinner.

   - bpo-43683(16): Add ASYNC_GEN_WRAP opcode to wrap the value to be
     yielded in async generators.  Removes the need to special case
     async generators in the ‘YIELD_VALUE’ instruction.

   - bpo-46407(17): Optimize some modulo operations in
     ‘Objects/longobject.c’.  Patch by Jeremiah Vivian.

   - bpo-46409(18): Add new ‘RETURN_GENERATOR’ bytecode to make
     generators.  Simplifies calling Python functions in the VM, as they
     no longer any need to special case generator functions.

     Also add ‘JUMP_NO_INTERRUPT’ bytecode that acts like
     ‘JUMP_ABSOLUTE’, but does not check for interrupts.

   - bpo-46406(19): The integer division ‘//’ implementation has been
     optimized to better let the compiler understand its constraints.
     It can be 20% faster on the amd64 platform when dividing an int by
     a value smaller than ‘2**30’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45773

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46564

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45885

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44977

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46458

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46527

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46528

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46329

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46503

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46431

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46476

   (12) https://bugs.python.org/issue?@action=redirect&bpo=46481

   (13) https://peps.python.org/pep-0590/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=46417

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46417

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43683

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46407

   (18) https://bugs.python.org/issue?@action=redirect&bpo=46409

   (19) https://bugs.python.org/issue?@action=redirect&bpo=46406


File: python.info,  Node: Library<73>,  Next: Core and Builtins<72>,  Prev: Core and Builtins<71>,  Up: Python 3 11 0 alpha 5

1.23.39.2 Library
.................

   - bpo-46383(1): Fix invalid signature of ‘_zoneinfo’’s ‘module_free’
     function to resolve a crash on wasm32-emscripten platform.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46383


File: python.info,  Node: Core and Builtins<72>,  Next: Library<74>,  Prev: Library<73>,  Up: Python 3 11 0 alpha 5

1.23.39.3 Core and Builtins
...........................

   - bpo-46361(1): Ensure that “small” integers created by *note
     int.from_bytes(): 198d. and *note decimal.Decimal: 29d. are
     properly cached.

   - bpo-46161(2): Fix the class building error when the arguments are
     constants and CALL_FUNCTION_EX is used.

   - bpo-46028(3): Fixes calculation of ‘sys._base_executable’ when
     inside a virtual environment that uses symlinks with different
     binary names than the base environment provides.

   - bpo-46091(4): Correctly calculate indentation levels for lines with
     whitespace character that are ended by line continuation
     characters.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46361

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46161

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46028

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46091


File: python.info,  Node: Library<74>,  Next: Build<36>,  Prev: Core and Builtins<72>,  Up: Python 3 11 0 alpha 5

1.23.39.4 Library
.................

   - bpo-30512(1): Add CAN Socket support for NetBSD.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30512


File: python.info,  Node: Build<36>,  Next: Core and Builtins<73>,  Prev: Library<74>,  Up: Python 3 11 0 alpha 5

1.23.39.5 Build
...............

   - bpo-46045(1): Do not use POSIX semaphores on NetBSD

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46045


File: python.info,  Node: Core and Builtins<73>,  Next: Library<75>,  Prev: Build<36>,  Up: Python 3 11 0 alpha 5

1.23.39.6 Core and Builtins
...........................

   - bpo-44024(1): Improve the *note TypeError: 2c3. message for
     non-string second arguments passed to the built-in functions *note
     getattr(): bf0. and *note hasattr(): 4d5.  Patch by Géry Ogam.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44024


File: python.info,  Node: Library<75>,  Next: Documentation<30>,  Prev: Core and Builtins<73>,  Up: Python 3 11 0 alpha 5

1.23.39.7 Library
.................

   - bpo-46624(1): Restore support for non-integer arguments of *note
     random.randrange(): 872. and *note random.randint(): 1275.

   - bpo-46591(2): Make the IDLE doc URL on the About IDLE dialog
     clickable.

   - bpo-46565(3): Remove loop variables that are leaking into modules’
     namespaces.

   - bpo-46553(4): In *note typing.get_type_hints(): 6b4, support
     evaluating bare stringified ‘ClassVar’ annotations.  Patch by
     Gregory Beauregard.

   - bpo-46544(5): Don’t leak ‘x’ & ‘uspace’ intermediate vars in *note
     textwrap.TextWrapper: 1008.

   - bpo-46487(6): Add the ‘get_write_buffer_limits’ method to
     ‘asyncio.transports.WriteTransport’ and to the SSL transport.

   - bpo-45173(7): Note the configparser deprecations will be removed in
     Python 3.12.

   - bpo-45162(8): The deprecated *note unittest: 106. APIs removed in
     3.11a1 have been temporarily restored to be removed in 3.12 while
     cleanups in external projects go in.

   - bpo-46539(9): In *note typing.get_type_hints(): 6b4, support
     evaluating stringified ‘ClassVar’ and ‘Final’ annotations inside
     ‘Annotated’.  Patch by Gregory Beauregard.

   - bpo-46510(10): Add missing test for *note types.TracebackType: b0b.
     and *note types.FrameType: 1992.  Calculate them directly from the
     caught exception without calling *note sys.exc_info(): 68d.

   - bpo-46491(11): Allow *note typing.Annotated: 947. to wrap *note
     typing.Final: 267. and *note typing.ClassVar: 266.  Patch by
     Gregory Beauregard.

   - bpo-46483(12): Remove *note __class_getitem__(): 73e. from *note
     pathlib.PurePath: 4a9. as this class was not supposed to be
     generic.

   - bpo-46436(13): Fix command-line option ‘-d’/‘--directory’ in module
     *note http.server: 72. which is ignored when combined with
     command-line option ‘--cgi’.  Patch by Géry Ogam.

   - bpo-41403(14): Make ‘mock.patch()’ raise a *note TypeError: 2c3.
     with a relevant error message on invalid arg.  Previously it
     allowed a cryptic *note AttributeError: 34e. to escape.

   - bpo-46474(15): In ‘importlib.metadata.EntryPoint.pattern’, avoid
     potential REDoS by limiting ambiguity in consecutive whitespace.

   - bpo-46474(16): Removed private method from
     ‘importlib.metadata.Path’.  Sync with importlib_metadata 4.10.0.

   - bpo-46470(17): Remove unused branch from
     ‘typing._remove_dups_flatten’

   - bpo-46469(18): *note asyncio: a. generic classes now return *note
     types.GenericAlias: 7f0. in ‘__class_getitem__’ instead of the same
     class.

   - bpo-41906(19): Support passing filter instances in the ‘filters’
     values of ‘handlers’ and ‘loggers’ in the dictionary passed to
     *note logging.config.dictConfig(): 11f4.

   - bpo-46422(20): Use ‘dis.Positions’ in ‘dis.Instruction’ instead of
     a regular ‘tuple’.

   - bpo-46434(21): *note pdb: a5. now gracefully handles ‘help’ when
     *note __doc__: 1993. is missing, for example when run with
     pregenerated optimized ‘.pyc’ files.

   - bpo-43869(22): Python uses the same time Epoch on all platforms.
     Add an explicit unit test to ensure that it’s the case.  Patch by
     Victor Stinner.

   - bpo-46414(23): Add *note typing.reveal_type(): 6ad.  Patch by Jelle
     Zijlstra.

   - bpo-40280(24): *note subprocess: d6. now imports Windows-specific
     imports when ‘msvcrt’ module is available, and POSIX-specific
     imports on all other platforms.  This gives a clean exception when
     ‘_posixsubprocess’ is not available (e.g.  Emscripten browser
     target).

   - bpo-40066(25): ‘IntEnum’, ‘IntFlag’, and ‘StrEnum’ use the mixed-in
     type for their ‘str()’ and ‘format()’ output.

   - bpo-46316(26): Optimize *note pathlib.Path.iterdir(): 173a. by
     removing an unnecessary check for special entries.

   - bpo-29688(27): Document *note pathlib.Path.absolute(): 17bf. (which
     has always existed).

   - bpo-43012(28): The pathlib module’s obsolete and internal
     ‘_Accessor’ class has been removed to prepare the terrain for
     upcoming enhancements to the module.

   - bpo-46258(29): Speed up *note math.isqrt(): a10. for small positive
     integers by replacing two division steps with a lookup table.

   - bpo-46242(30): Improve error message when creating a new *note
     enum.Enum: 633. type subclassing an existing ‘Enum’ with
     ‘_member_names_’ using ‘enum.Enum.__call__()’.

   - bpo-43118(31): Fix a bug in *note inspect.signature(): 73b. that
     was causing it to fail on some subclasses of classes with a
     ‘__text_signature__’ referencing module globals.  Patch by Weipeng
     Hong.

   - bpo-26552(32): Fixed case where failing *note
     asyncio.ensure_future(): c98. did not close the coroutine.  Patch
     by Kumar Aditya.

   - bpo-21987(33): Fix an issue with *note tarfile.TarFile.getmember():
     1994. getting a directory name with a trailing slash.

   - bpo-46124(34): Update *note zoneinfo: 134. to rely on
     importlib.resources traversable API.

   - bpo-46103(35): Now *note inspect.getmembers(): 1995. only gets
     ‘__bases__’ attribute from class type.  Patch by Weipeng Hong.

   - bpo-46080(36): Fix exception in argparse help text generation if a
     *note argparse.BooleanOptionalAction: 1996. argument’s default is
     ‘argparse.SUPPRESS’ and it has ‘help’ specified.  Patch by Felix
     Fontein.

   - bpo-44791(37): Fix substitution of *note ParamSpec: 15e. in *note
     Concatenate: 7c8. with different parameter expressions.
     Substitution with a list of types returns now a tuple of types.
     Substitution with ‘Concatenate’ returns now a ‘Concatenate’ with
     concatenated lists of arguments.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46624

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46591

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46565

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46553

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46544

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46487

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45173

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45162

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46539

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46510

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46491

   (12) https://bugs.python.org/issue?@action=redirect&bpo=46483

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46436

   (14) https://bugs.python.org/issue?@action=redirect&bpo=41403

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46474

   (16) https://bugs.python.org/issue?@action=redirect&bpo=46474

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46470

   (18) https://bugs.python.org/issue?@action=redirect&bpo=46469

   (19) https://bugs.python.org/issue?@action=redirect&bpo=41906

   (20) https://bugs.python.org/issue?@action=redirect&bpo=46422

   (21) https://bugs.python.org/issue?@action=redirect&bpo=46434

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43869

   (23) https://bugs.python.org/issue?@action=redirect&bpo=46414

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (25) https://bugs.python.org/issue?@action=redirect&bpo=40066

   (26) https://bugs.python.org/issue?@action=redirect&bpo=46316

   (27) https://bugs.python.org/issue?@action=redirect&bpo=29688

   (28) https://bugs.python.org/issue?@action=redirect&bpo=43012

   (29) https://bugs.python.org/issue?@action=redirect&bpo=46258

   (30) https://bugs.python.org/issue?@action=redirect&bpo=46242

   (31) https://bugs.python.org/issue?@action=redirect&bpo=43118

   (32) https://bugs.python.org/issue?@action=redirect&bpo=26552

   (33) https://bugs.python.org/issue?@action=redirect&bpo=21987

   (34) https://bugs.python.org/issue?@action=redirect&bpo=46124

   (35) https://bugs.python.org/issue?@action=redirect&bpo=46103

   (36) https://bugs.python.org/issue?@action=redirect&bpo=46080

   (37) https://bugs.python.org/issue?@action=redirect&bpo=44791


File: python.info,  Node: Documentation<30>,  Next: Tests<33>,  Prev: Library<75>,  Up: Python 3 11 0 alpha 5

1.23.39.8 Documentation
.......................

   - bpo-46463(1): Fixes ‘escape4chm.py’ script used when building the
     CHM documentation file

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46463


File: python.info,  Node: Tests<33>,  Next: Build<37>,  Prev: Documentation<30>,  Up: Python 3 11 0 alpha 5

1.23.39.9 Tests
...............

   - bpo-43478(1): Mocks can no longer be provided as the specs for
     other Mocks.  As a result, an already-mocked object cannot be
     passed to ‘mock.Mock()’.  This can uncover bugs in tests since
     these Mock-derived Mocks will always pass certain tests (e.g.
     isinstance) and builtin assert functions (e.g.
     assert_called_once_with) will unconditionally pass.

   - bpo-46616(2): Ensures ‘test_importlib.test_windows’ cleans up
     registry keys after completion.

   - bpo-44359(3): test_ftplib now silently ignores socket errors to
     prevent logging unhandled threading exceptions.  Patch by Victor
     Stinner.

   - bpo-46600(4): Fix test_gdb.test_pycfunction() for Python built with
     ‘clang -Og’.  Tolerate inlined functions in the gdb traceback.
     Patch by Victor Stinner.

   - bpo-46542(5): Fix a Python crash in test_lib2to3 when using Python
     built in debug mode: limit the recursion limit.  Patch by Victor
     Stinner.

   - bpo-46576(6): test_peg_generator now disables compiler optimization
     when testing compilation of its own C extensions to significantly
     speed up the testing on non-debug builds of CPython.

   - bpo-46542(7): Fix ‘test_json’ tests checking for *note
     RecursionError: d96.: modify these tests to use
     ‘support.infinite_recursion()’.  Patch by Victor Stinner.

   - bpo-13886(8): Skip test_builtin PTY tests on non-ASCII characters
     if the readline module is loaded.  The readline module changes
     input() behavior, but test_builtin is not intended to test the
     readline module.  Patch by Victor Stinner.

   - bpo-40280(9): Add ‘test.support.requires_fork()’ decorators to mark
     tests that require a working *note os.fork(): 197.

   - bpo-40280(10): Add ‘test.support.requires_subprocess()’ decorator
     to mark tests which require working *note subprocess: d6. module or
     ‘os.spawn*’.  The wasm32-emscripten platform has no support for
     processes.

   - bpo-46126(11): Disable ‘descriptions’ when running tests
     internally.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43478

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46616

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44359

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46600

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46542

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46576

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46542

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13886

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46126


File: python.info,  Node: Build<37>,  Next: Windows<31>,  Prev: Tests<33>,  Up: Python 3 11 0 alpha 5

1.23.39.10 Build
................

   - bpo-46602(1): Tidied up configure.ac so that conftest.c is
     truncated rather than appended.  This assists in the case where the
     ‘rm’ of conftest.c fails to happen between tests.  Downstream
     issues such as a clobbered SOABI can result.

   - bpo-46600(2): Fix the test checking if the C compiler supports
     ‘-Og’ option in the ‘./configure’ script to also use ‘-Og’ on clang
     which supports it.  Patch by Victor Stinner.

   - bpo-38472(3): Fix GCC detection in setup.py when cross-compiling.
     The C compiler is now run with LC_ALL=C. Previously, the detection
     failed with a German locale.

   - bpo-46513(4): ‘configure’ no longer uses ‘AC_C_CHAR_UNSIGNED’ macro
     and ‘pyconfig.h’ no longer defines reserved symbol
     ‘__CHAR_UNSIGNED__’.

   - bpo-46471(5): Use global singletons for single byte bytes objects
     in deepfreeze.

   - bpo-46443(6): Deepfreeze now uses cached small integers as it saves
     some space for common small integers.

   - bpo-46429(7): Merge all deep-frozen files into one for space
     savings.  Patch by Kumar Aditya.

   - bpo-45569(8): The build now defaults to using 30-bit digits for
     Python integers.  Previously either 15-bit or 30-bit digits would
     be selected, depending on the platform.  15-bit digits may still be
     selected using the ‘--enable-big-digits=15’ option to the
     ‘configure’ script, or by defining ‘PYLONG_BITS_IN_DIGIT’ in
     ‘pyconfig.h’.

   - bpo-45925(9): Update Windows installer to use SQLite 3.37.2.

   - bpo-43112(10): Detect musl libc as a separate SOABI (tagged as
     ‘linux-musl’).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46602

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46600

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38472

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46513

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46471

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46443

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46429

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45569

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45925

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43112


File: python.info,  Node: Windows<31>,  Next: macOS<23>,  Prev: Build<37>,  Up: Python 3 11 0 alpha 5

1.23.39.11 Windows
..................

   - bpo-33125(1): The traditional EXE/MSI based installer for Windows
     is now available for ARM64

   - bpo-46362(2): os.path.abspath(“C:CON”) is now fixed to return
     “\.CON”, not the same path.  The regression was true of all legacy
     DOS devices such as COM1, LPT1, or NUL.

   - bpo-44934(3): The installer now offers a command-line only option
     to add the installation directory to the end of ‘PATH’ instead of
     at the start.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33125

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46362

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44934


File: python.info,  Node: macOS<23>,  Next: IDLE<21>,  Prev: Windows<31>,  Up: Python 3 11 0 alpha 5

1.23.39.12 macOS
................

   - bpo-45925(1): Update macOS installer to SQLite 3.37.2.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45925


File: python.info,  Node: IDLE<21>,  Next: C API<32>,  Prev: macOS<23>,  Up: Python 3 11 0 alpha 5

1.23.39.13 IDLE
...............

   - bpo-45296(1): Clarify close, quit, and exit in IDLE. In the File
     menu, ‘Close’ and ‘Exit’ are now ‘Close Window’ (the current one)
     and ‘Exit’ is now ‘Exit IDLE’ (by closing all windows).  In Shell,
     ‘quit()’ and ‘exit()’ mean ‘close Shell’.  If there are no other
     windows, this also exits IDLE.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45296


File: python.info,  Node: C API<32>,  Prev: IDLE<21>,  Up: Python 3 11 0 alpha 5

1.23.39.14 C API
................

   - bpo-40170(1): Remove the ‘PyHeapType_GET_MEMBERS()’ macro.  It was
     exposed in the public C API by mistake, it must only be used by
     Python internally.  Use the ‘PyTypeObject.tp_members’ member
     instead.  Patch by Victor Stinner.

   - bpo-40170(2): Move _Py_GetAllocatedBlocks() and
     _PyObject_DebugMallocStats() private functions to the internal C
     API. Patch by Victor Stinner.

   - bpo-46433(3): The internal function _PyType_GetModuleByDef now
     correctly handles inheritance patterns involving static types.

   - bpo-45459(4): *note Py_buffer: 75b. and various ‘Py_buffer’ related
     functions are now part of the limited API and stable ABI.

   - bpo-14916(5): Fixed bug in the tokenizer that prevented
     ‘PyRun_InteractiveOne’ from parsing from the provided FD.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46433

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45459

   (5) https://bugs.python.org/issue?@action=redirect&bpo=14916


File: python.info,  Node: Python 3 11 0 alpha 4,  Next: Python 3 11 0 alpha 3,  Prev: Python 3 11 0 alpha 5,  Up: Changelog

1.23.40 Python 3.11.0 alpha 4
-----------------------------

'Release date: 2022-01-13'

* Menu:

* Core and Builtins: Core and Builtins<74>.
* Library: Library<76>.
* Core and Builtins: Core and Builtins<75>.
* Library: Library<77>.
* Core and Builtins: Core and Builtins<76>.
* Library: Library<78>.
* Core and Builtins: Core and Builtins<77>.
* Library: Library<79>.
* Documentation: Documentation<31>.
* Tests: Tests<34>.
* Build: Build<38>.
* Windows: Windows<32>.
* macOS: macOS<24>.
* C API: C API<33>.


File: python.info,  Node: Core and Builtins<74>,  Next: Library<76>,  Up: Python 3 11 0 alpha 4

1.23.40.1 Core and Builtins
...........................

   - bpo-46070(1): *note Py_EndInterpreter(): 19a0. now explicitly
     untracks all objects currently tracked by the GC. Previously, if an
     object was used later by another interpreter, calling *note
     PyObject_GC_UnTrack(): 1555. on the object crashed if the previous
     or the next object of the ‘PyGC_Head’ structure became a dangling
     pointer.  Patch by Victor Stinner.

   - bpo-46347(2): Fix memory leak in PyEval_EvalCodeEx.

   - bpo-46339(3): Fix a crash in the parser when retrieving the error
     text for multi-line f-strings expressions that do not start in the
     first line of the string.  Patch by Pablo Galindo

   - bpo-46331(4): Do not set line number of instruction storing
     doc-string.  Fixes regression introduced in 3.11 alpha.

   - bpo-46314(5): Remove spurious “call” event when creating a lambda
     function that was accidentally introduced in 3.11a4.

   - bpo-46289(6): ASDL declaration of ‘FormattedValue’ has changed to
     reflect ‘conversion’ field is not optional.

   - bpo-46297(7): Fixed an interpreter crash on bootup with multiple
     PythonPaths set in the Windows registry.  Patch by Derzsi Dániel.

   - bpo-46237(8): Fix the line number of tokenizer errors inside
     f-strings.  Patch by Pablo Galindo.

   - bpo-46263(9): We always expect the “use_frozen_modules” config to
     be set, now that getpath.c was rewritten in pure Python and the
     logic improved.

   - bpo-46006(10): Fix a regression when a type method like
     ‘__init__()’ is modified in a subinterpreter.  Fix a regression in
     ‘_PyUnicode_EqualToASCIIId()’ and type ‘update_slot()’.  Revert the
     change which made the Unicode dictionary of interned strings
     compatible with subinterpreters: the internal interned dictionary
     is shared again by all interpreters.  Patch by Victor Stinner.

   - bpo-45923(11): Add RESUME opcode.  This is a logical no-op.  It is
     emitted by the compiler anywhere a Python function can be entered.
     It is used by the interpreter to perform tracing and optimizer
     checks.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46070

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46347

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46339

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46331

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46314

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46289

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46297

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46237

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46263

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46006

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45923


File: python.info,  Node: Library<76>,  Next: Core and Builtins<75>,  Prev: Core and Builtins<74>,  Up: Python 3 11 0 alpha 4

1.23.40.2 Library
.................

   - bpo-46208(1): Fix the regression of os.path.normpath(“A/../../B”)
     not returning expected “../B” but “B”.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46208


File: python.info,  Node: Core and Builtins<75>,  Next: Library<77>,  Prev: Library<76>,  Up: Python 3 11 0 alpha 4

1.23.40.3 Core and Builtins
...........................

   - bpo-46240(1): Correct the error message for unclosed parentheses
     when the tokenizer doesn’t reach the end of the source when the
     error is reported.  Patch by Pablo Galindo

   - bpo-46009(2): Remove the ‘GEN_START’ opcode.

   - bpo-46235(3): Certain sequence multiplication operations like ‘[0]
     * 1_000’ are now faster due to reference-counting optimizations.
     Patch by Dennis Sweeney.

   - bpo-46221(4): ‘PREP_RERAISE_STAR’ no longer pushes ‘lasti’ to the
     stack.

   - bpo-46202(5): Remove ‘POP_EXCEPT_AND_RERAISE’ and replace it by an
     equivalent sequence of other opcodes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46240

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46009

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46235

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46221

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46202


File: python.info,  Node: Library<77>,  Next: Core and Builtins<76>,  Prev: Core and Builtins<75>,  Up: Python 3 11 0 alpha 4

1.23.40.4 Library
.................

   - bpo-46085(1): Fix iterator cache mechanism of ‘OrderedDict’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46085


File: python.info,  Node: Core and Builtins<76>,  Next: Library<78>,  Prev: Library<77>,  Up: Python 3 11 0 alpha 4

1.23.40.5 Core and Builtins
...........................

   - bpo-46055(1): Speed up shifting operation involving integers less
     than ‘PyLong_BASE’.  Patch by Xinhang Xu.

   - bpo-46110(2): Add a maximum recursion check to the PEG parser to
     avoid stack overflow.  Patch by Pablo Galindo

   - bpo-46107(3): Fix bug where ‘ExceptionGroup.split()’ and
     ‘ExceptionGroup.subgroup()’ did not copy the exception group’s
     ‘__note__’ field to the parts.

   - bpo-45711(4): The interpreter state’s representation of handled
     exceptions (a.k.a exc_info, or _PyErr_StackItem) now has only the
     ‘exc_value’ field, ‘exc_type’ and ‘exc_traceback’ have been removed
     as their values can be derived from ‘exc_value’.

   - bpo-44525(5): Replace the four call bytecode instructions which one
     pre-call instruction and two call instructions.

     Removes ‘CALL_FUNCTION’, ‘CALL_FUNCTION_KW’, ‘CALL_METHOD’ and
     ‘CALL_METHOD_KW’.

     Adds ‘CALL_NO_KW’ and ‘CALL_KW’ call instructions, and
     ‘PRECALL_METHOD’ prefix for pairing with ‘LOAD_METHOD’.

   - bpo-46039(6): Remove the ‘YIELD_FROM’ instruction and replace it
     with the ‘SEND’ instruction which performs the same operation, but
     without the loop.

   - bpo-45635(7): The code called from ‘_PyErr_Display()’ was
     refactored to improve error handling.  It now exits immediately
     upon an unrecoverable error.

   - bpo-46054(8): Fix parser error when parsing non-utf8 characters in
     source files.  Patch by Pablo Galindo.

   - bpo-46042(9): Improve the location of the caret in *note
     SyntaxError: 18d. exceptions emitted by the symbol table.  Patch by
     Pablo Galindo.

   - bpo-46049(10): Ensure ‘._pth’ files work as intended on platforms
     other than Windows.

   - bpo-46048(11): Fixes parsing of ‘._pth’ files on startup so that
     single-character paths are correctly read.

   - bpo-37971(12): Fix a bug where the line numbers given in a
     traceback when a decorator application raised an exception were
     wrong.

   - bpo-46031(13): Add *note POP_JUMP_IF_NOT_NONE: 1926. and *note
     POP_JUMP_IF_NONE: 1925. opcodes to speed up conditional jumps.

   - bpo-45654(14): Deepfreeze *note runpy: be, patch by Kumar Aditya.

   - bpo-46025(15): Fix a crash in the *note atexit: c. module involving
     functions that unregister themselves before raising exceptions.
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46055

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46110

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46107

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44525

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46039

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45635

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46054

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46042

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46049

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46048

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37971

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46031

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45654

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46025


File: python.info,  Node: Library<78>,  Next: Core and Builtins<77>,  Prev: Core and Builtins<76>,  Up: Python 3 11 0 alpha 4

1.23.40.6 Library
.................

   - bpo-46000(1): Improve compatibility of the *note curses: 2b. module
     with NetBSD curses.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46000


File: python.info,  Node: Core and Builtins<77>,  Next: Library<79>,  Prev: Library<78>,  Up: Python 3 11 0 alpha 4

1.23.40.7 Core and Builtins
...........................

   - bpo-44525(1): Specialize the CALL_FUNCTION instruction for calls to
     builtin types with a single argument.  Speeds up ‘range(x)’,
     ‘list(x)’, and specifically ‘type(obj)’.

   - bpo-42918(2): Fix bug where the built-in *note compile(): 192.
     function did not always raise a *note SyntaxError: 18d. when passed
     multiple statements in ‘single’ mode.  Patch by Weipeng Hong.

   - bpo-45953(3): The main interpreter in _PyRuntimeState.interpreters
     is now statically allocated (as part of _PyRuntime).  Likewise for
     the initial thread state of each interpreter.  This means less
     allocation during runtime init, as well as better memory locality
     for these key state objects.

   - bpo-45292(4): Complete the PEP 654(5) implementation: add
     ‘except*’.

   - bpo-43413(6): Revert changes in ‘set.__init__’.  Subclass of *note
     set: 5dc. needs to define a ‘__init__()’ method if it defines a
     ‘__new__()’ method with additional keyword parameters.

   - bpo-43931(7): Added the *note Py_Version: 759. constant which bears
     the same value as *note PY_VERSION_HEX: 75a.  Patch by Gabriele N.
     Tornetta.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44525

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42918

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45953

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45292

   (5) https://peps.python.org/pep-0654/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43413

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43931


File: python.info,  Node: Library<79>,  Next: Documentation<31>,  Prev: Core and Builtins<77>,  Up: Python 3 11 0 alpha 4

1.23.40.8 Library
.................

   - bpo-46342(1): The ‘@typing.final’ decorator now sets the
     ‘__final__’ attribute on the decorated object to allow runtime
     introspection.  Patch by Jelle Zijlstra.

   - bpo-46328(2): Added the *note sys.exception(): 68e. method which
     returns the active exception instance.

   - bpo-46307(3): Add *note string.Template.is_valid(): 689. and *note
     string.Template.get_identifiers(): 688. methods.

   - bpo-46306(4): Assume that *note types.CodeType: 2df. always has
     ‘types.CodeType.co_firstlineno’ in *note doctest: 3a.

   - bpo-40479(5): Fix *note hashlib: 68. 'usedforsecurity' option to
     work correctly with OpenSSL 3.0.0 in FIPS mode.

   - bpo-46070(6): Fix possible segfault when importing the *note
     asyncio: a. module from different sub-interpreters in parallel.
     Patch by Erlend E. Aasland.

   - bpo-46244(7): Removed ‘__slots__’ from *note typing.ParamSpec: 15e.
     and *note typing.TypeVar: 15d.  They served no purpose.  Patch by
     Arie Bovenberg.

   - bpo-46278(8): Reflect ‘context’ argument in
     ‘AbstractEventLoop.call_*()’ methods.  Loop implementations already
     support it.

   - bpo-46269(9): Remove special-casing of ‘__new__’ in *note
     enum.Enum.__dir__(): 19a8.

   - bpo-46266(10): Improve day constants in *note calendar: 14.

     Now all constants (‘MONDAY’ … ‘SUNDAY’) are documented, tested, and
     added to ‘__all__’.

   - bpo-46257(11): Optimized the mean, variance, and stdev functions in
     the statistics module.  If the input is an iterator, it is consumed
     in a single pass rather than eating memory by conversion to a list.
     The single pass algorithm is about twice as fast as the previous
     two pass code.

   - bpo-41011(12): Added two new variables to 'pyvenv.cfg' which is
     generated by *note venv: 111. module: 'executable' for the
     executable and 'command' for the command line used to create the
     environment.

   - bpo-46239(13): Improve error message when importing
     ‘asyncio.windows_events’ on non-Windows.

   - bpo-46238(14): Reuse ‘_winapi’ constants in
     ‘asyncio.windows_events’.

   - bpo-46222(15): Adding ‘SF_NOCACHE’ sendfile constant for FreeBSD
     for the posixmodule.

   - bpo-37295(16): Add fast path for ‘0 <= k <= n <= 67’ for *note
     math.comb(): 6d3.

   - bpo-46176(17): Adding the ‘MAP_STACK’ constant for the mmap module.

   - bpo-43424(18): Deprecate ‘webbrowser.MacOSXOSAScript._name’ and use
     ‘name’ instead.

   - bpo-45321(19): Added missing error codes to module
     ‘xml.parsers.expat.errors’.

   - bpo-46125(20): Refactor tests to test traversable API directly.
     Includes changes from importlib 5.4.0.

   - bpo-46118(21): Moved importlib.resources and its related
     functionality to a package.

   - bpo-37578(22): Add 'include_hidden' parameter to *note glob(): 29f.
     and *note iglob(): 80d. to match hidden files and directories when
     using special characters like ‘*’, ‘**’, ‘?’ and ‘[]’.

   - bpo-20369(23): *note concurrent.futures.wait(): 19a9. no longer
     blocks forever when given duplicate Futures.  Patch by Kumar
     Aditya.

   - bpo-46105(24): Honor spec when generating requirement specs with
     urls and extras (importlib_metadata 4.8.3).

   - bpo-44893(25): EntryPoint objects are no longer tuples.
     Recommended means to access is by attribute (‘.name’, ‘.group’) or
     accessor (‘.load()’).  Access by index is deprecated and will raise
     deprecation warning.

   - bpo-22815(26): Print unexpected successes together with failures
     and errors in summary in *note unittest.TextTestResult: 534.

   - bpo-22047(27): Calling ‘add_argument_group()’ on an argument group
     is deprecated.  Calling ‘add_argument_group()’ or
     ‘add_mutually_exclusive_group()’ on a mutually exclusive group is
     deprecated.

     These features were never supported and do not always work
     correctly.  The functions exist on the API by accident through
     inheritance and will be removed in the future.

   - bpo-26952(28): *note argparse: 6. raises *note ValueError: 202.
     with clear message when trying to render usage for an empty
     mutually exclusive group.  Previously it raised a cryptic *note
     IndexError: 1585.

   - bpo-45615(29): Functions in the *note traceback: fe. module raise
     *note TypeError: 2c3. rather than *note AttributeError: 34e. when
     an exception argument is not of type *note BaseException: 5be.

   - bpo-16594(30): Add allow allow_reuse_port flag in socketserver.

   - bpo-27718(31): Fix help for the *note signal: c6. module.  Some
     functions (e.g.  ‘signal()’ and ‘getsignal()’) were omitted.

   - bpo-46032(32): The ‘registry()’ method of *note
     functools.singledispatch(): 63c. functions checks now the first
     argument or the first parameter annotation and raises a TypeError
     if it is not supported.  Previously unsupported “types” were
     ignored (e.g.  ‘typing.List[int]’) or caused an error at calling
     time (e.g.  ‘list[int]’).

   - bpo-46014(33): Add ability to use ‘typing.Union’ and
     ‘types.UnionType’ as dispatch argument to
     ‘functools.singledispatch’.  Patch provided by Yurii Karabas.

   - bpo-27062(34): Add ‘__all__’ to *note inspect: 7e, patch by Kumar
     Aditya.

   - bpo-46018(35): Ensure that *note math.expm1(): 1231. does not raise
     on underflow.

   - bpo-46016(36): Adding ‘F_DUP2FD’ and ‘F_DUP2FD_CLOEXEC’ constants
     from FreeBSD into the *note fcntl: 59. module.

   - bpo-45755(37): *note typing: 104. generic aliases now reveal the
     class attributes of the original generic class when passed to
     ‘dir()’.  This was the behavior up to Python 3.6, but was changed
     in 3.7-3.9.

   - bpo-45874(38): The empty query string, consisting of no query
     arguments, is now handled correctly in ‘urllib.parse.parse_qsl’.
     This caused problems before when strict parsing was enabled.

   - bpo-44674(39): Change how dataclasses disallows mutable default
     values.  It used to use a list of known types (list, dict, set).
     Now it disallows unhashable objects to be defaults.  It’s using
     unhashability as a proxy for mutability.  Patch by Eric V. Smith,
     idea by Raymond Hettinger.

   - bpo-23882(40): Remove namespace package (PEP 420) support from
     unittest discovery.  It was introduced in Python 3.4 but has been
     broken since Python 3.7.

   - bpo-25066(41): Added a ‘__repr__()’ method to *note
     multiprocessing.Event: 19aa. objects, patch by Kumar Aditya.

   - bpo-45643(42): Added *note signal.SIGSTKFLT: 19ab. on platforms
     where this signal is defined.

   - bpo-44092(43): Fetch across rollback no longer raises *note
     InterfaceError: 680.  Instead we leave it to the SQLite library to
     handle these cases.  Patch by Erlend E. Aasland.

   - bpo-42413(44): Replace ‘concurrent.futures.TimeoutError’ and
     ‘asyncio.TimeoutError’ with builtin *note TimeoutError: 83b, keep
     these names as deprecated aliases.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46342

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46328

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46307

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46306

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40479

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46070

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46244

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46278

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46269

   (10) https://bugs.python.org/issue?@action=redirect&bpo=46266

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46257

   (12) https://bugs.python.org/issue?@action=redirect&bpo=41011

   (13) https://bugs.python.org/issue?@action=redirect&bpo=46239

   (14) https://bugs.python.org/issue?@action=redirect&bpo=46238

   (15) https://bugs.python.org/issue?@action=redirect&bpo=46222

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37295

   (17) https://bugs.python.org/issue?@action=redirect&bpo=46176

   (18) https://bugs.python.org/issue?@action=redirect&bpo=43424

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45321

   (20) https://bugs.python.org/issue?@action=redirect&bpo=46125

   (21) https://bugs.python.org/issue?@action=redirect&bpo=46118

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37578

   (23) https://bugs.python.org/issue?@action=redirect&bpo=20369

   (24) https://bugs.python.org/issue?@action=redirect&bpo=46105

   (25) https://bugs.python.org/issue?@action=redirect&bpo=44893

   (26) https://bugs.python.org/issue?@action=redirect&bpo=22815

   (27) https://bugs.python.org/issue?@action=redirect&bpo=22047

   (28) https://bugs.python.org/issue?@action=redirect&bpo=26952

   (29) https://bugs.python.org/issue?@action=redirect&bpo=45615

   (30) https://bugs.python.org/issue?@action=redirect&bpo=16594

   (31) https://bugs.python.org/issue?@action=redirect&bpo=27718

   (32) https://bugs.python.org/issue?@action=redirect&bpo=46032

   (33) https://bugs.python.org/issue?@action=redirect&bpo=46014

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27062

   (35) https://bugs.python.org/issue?@action=redirect&bpo=46018

   (36) https://bugs.python.org/issue?@action=redirect&bpo=46016

   (37) https://bugs.python.org/issue?@action=redirect&bpo=45755

   (38) https://bugs.python.org/issue?@action=redirect&bpo=45874

   (39) https://bugs.python.org/issue?@action=redirect&bpo=44674

   (40) https://bugs.python.org/issue?@action=redirect&bpo=23882

   (41) https://bugs.python.org/issue?@action=redirect&bpo=25066

   (42) https://bugs.python.org/issue?@action=redirect&bpo=45643

   (43) https://bugs.python.org/issue?@action=redirect&bpo=44092

   (44) https://bugs.python.org/issue?@action=redirect&bpo=42413


File: python.info,  Node: Documentation<31>,  Next: Tests<34>,  Prev: Library<79>,  Up: Python 3 11 0 alpha 4

1.23.40.9 Documentation
.......................

   - bpo-46196(1): Document method *note cmd.Cmd.columnize(): 19ad.

   - bpo-46120(2): State that ‘|’ is preferred for readability over
     ‘Union’ in the *note typing: 104. docs.

   - bpo-46109(3): Extracted ‘importlib.resources’ and
     ‘importlib.resources.abc’ documentation into separate files.

   - bpo-19737(4): Update the documentation for the *note globals():
     19ae. function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46196

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46120

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46109

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19737


File: python.info,  Node: Tests<34>,  Next: Build<38>,  Prev: Documentation<31>,  Up: Python 3 11 0 alpha 4

1.23.40.10 Tests
................

   - bpo-46296(1): Add a test case for *note enum: 56. with ‘_use_args_
     == True’ and ‘_member_type_ == object’.

   - bpo-46205(2): Fix hang in runtest_mp due to race condition

   - bpo-46263(3): Fix test_capi on FreeBSD 14-dev: instruct jemalloc to
     not fill freed memory with junk byte.

   - bpo-46262(4): Cover ‘ValueError’ path in tests for
     ‘enum.Flag._missing_()’.

   - bpo-46150(5): Now ‘fakename’ in
     ‘test_pathlib.PosixPathTest.test_expanduser’ is checked to be
     non-existent.

   - bpo-46129(6): Rewrite ‘asyncio.locks’ tests with *note
     unittest.IsolatedAsyncioTestCase: 30c. usage.

   - bpo-23819(7): Fixed *note asyncio: a. tests in python optimized
     mode.  Patch by Kumar Aditya.

   - bpo-46114(8): Fix test case for OpenSSL 3.0.1 version.  OpenSSL 3.0
     uses ‘0xMNN00PP0L’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46296

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46205

   (3) https://bugs.python.org/issue?@action=redirect&bpo=46263

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46262

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46150

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46129

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23819

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46114


File: python.info,  Node: Build<38>,  Next: Windows<32>,  Prev: Tests<34>,  Up: Python 3 11 0 alpha 4

1.23.40.11 Build
................

   - bpo-44133(1): When Python is configured with *note
     -without-static-libpython: 895, the Python static library
     (libpython.a) is no longer built.  Patch by Victor Stinner.

   - bpo-44133(2): When Python is built without *note -enable-shared:
     869, the ‘python’ program is now linked to object files, rather
     than being linked to the Python static library (libpython.a), to
     make sure that all symbols are exported.  Previously, the linker
     omitted some symbols like the ‘Py_FrozenMain()’ function.  Patch by
     Victor Stinner.

   - bpo-40280(3): The ‘configure’ script has a new option
     ‘--with-emscripten-target’ to select browser or node as Emscripten
     build target.

   - bpo-46315(4): Added and fixed ‘#ifdef HAVE_FEATURE’ checks for
     functionality that is not available on WASI platform.

   - bpo-45723(5): Fixed a regression in ‘configure’ check for *note
     select.epoll(): fcd.

   - bpo-46263(6): ‘configure’ no longer sets ‘MULTIARCH’ on FreeBSD
     platforms.

   - bpo-46106(7): Updated OpenSSL to 1.1.1m in Windows builds, macOS
     installer builds, and CI. Patch by Kumar Aditya.

   - bpo-46088(8): Automatically detect or install bootstrap Python
     runtime when building from Visual Studio.

   - bpo-46072(9): Add a –with-pystats configure option to turn on
     internal statistics gathering.

   - bpo-40280(10): A new directory ‘Tools/wasm’ contains
     WebAssembly-related helpers like ‘config.site’ override for
     wasm32-emscripten, wasm assets generator to bundle the stdlib, and
     a README.

   - bpo-46023(11): ‘makesetup’ no longer builds extensions that have
     been marked as 'disabled'.  This allows users to disable modules in
     ‘Modules/Setup.local’.

   - bpo-45949(12): Use pure Python ‘freeze_module’ for all but
     importlib bootstrap files.  ‘--with-freeze-module’ ‘configure’
     option is no longer needed for cross builds.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44133

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44133

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (4) https://bugs.python.org/issue?@action=redirect&bpo=46315

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (6) https://bugs.python.org/issue?@action=redirect&bpo=46263

   (7) https://bugs.python.org/issue?@action=redirect&bpo=46106

   (8) https://bugs.python.org/issue?@action=redirect&bpo=46088

   (9) https://bugs.python.org/issue?@action=redirect&bpo=46072

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (11) https://bugs.python.org/issue?@action=redirect&bpo=46023

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45949


File: python.info,  Node: Windows<32>,  Next: macOS<24>,  Prev: Build<38>,  Up: Python 3 11 0 alpha 4

1.23.40.12 Windows
..................

   - bpo-46217(1): Removed parameter that is unsupported on Windows 8.1
     and early Windows 10 and may have caused build or runtime failures.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46217


File: python.info,  Node: macOS<24>,  Next: C API<33>,  Prev: Windows<32>,  Up: Python 3 11 0 alpha 4

1.23.40.13 macOS
................

   - bpo-40477(1): The Python Launcher app for macOS now properly
     launches scripts and, if necessary, the Terminal app when running
     on recent macOS releases.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40477


File: python.info,  Node: C API<33>,  Prev: macOS<24>,  Up: Python 3 11 0 alpha 4

1.23.40.14 C API
................

   - bpo-46236(1): Fix a bug in *note PyFunction_GetAnnotations(): 18da.
     that caused it to return a ‘tuple’ instead of a ‘dict’.

   - bpo-46140(2): *note PyBuffer_GetPointer(): 75c, *note
     PyBuffer_FromContiguous(): 75f, *note PyBuffer_ToContiguous(): 75e.
     and *note PyMemoryView_FromBuffer(): 764. now take buffer info by
     ‘const Py_buffer *’ instead of ‘Py_buffer *’, as they do not need
     mutability.  ‘PyBuffer_FromContiguous()’ also now takes the source
     buffer as ‘const void *’, and similarly ‘PyBuffer_GetPointer()’
     takes the strides as ‘const Py_ssize_t *’.

   - bpo-45855(3): Document that the 'no_block' argument to *note
     PyCapsule_Import(): 19b4. is a no-op now.

   - bpo-45855(4): Replaced deprecated usage of *note
     PyImport_ImportModuleNoBlock(): 3c0. with *note
     PyImport_ImportModule(): 3c1. in stdlib modules.  Patch by Kumar
     Aditya.

   - bpo-46007(5): The ‘PyUnicode_CHECK_INTERNED()’ macro has been
     excluded from the limited C API. It was never usable there, because
     it used internal structures which are not available in the limited
     C API. Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46236

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46140

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45855

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45855

   (5) https://bugs.python.org/issue?@action=redirect&bpo=46007


File: python.info,  Node: Python 3 11 0 alpha 3,  Next: Python 3 11 0 alpha 2,  Prev: Python 3 11 0 alpha 4,  Up: Changelog

1.23.41 Python 3.11.0 alpha 3
-----------------------------

'Release date: 2021-12-08'

* Menu:

* Core and Builtins: Core and Builtins<78>.
* Library: Library<80>.
* Core and Builtins: Core and Builtins<79>.
* Library: Library<81>.
* Documentation: Documentation<32>.
* Tests: Tests<35>.
* Build: Build<39>.
* Windows: Windows<33>.
* macOS: macOS<25>.
* C API: C API<34>.


File: python.info,  Node: Core and Builtins<78>,  Next: Library<80>,  Up: Python 3 11 0 alpha 3

1.23.41.1 Core and Builtins
...........................

   - bpo-46009(1): Restore behavior from 3.9 and earlier when sending
     non-None to newly started generator.  In 3.9 this did not affect
     the state of the generator.  In 3.10.0 and 3.10.1
     ‘gen_func().send(0)’ is equivalent to
     ‘gen_func().throw(TypeError(...)’ which exhausts the generator.  In
     3.10.2 onward, the behavior has been reverted to that of 3.9.

   - bpo-46004(2): Fix the *note SyntaxError: 18d. location for errors
     involving for loops with invalid targets.  Patch by Pablo Galindo

   - bpo-45711(3): ‘_PyErr_ChainStackItem()’ no longer normalizes
     ‘exc_info’ (including setting the traceback on the exception
     instance) because ‘exc_info’ is always normalized.

   - bpo-45607(4): The ‘__note__’ field was added to *note
     BaseException: 5be.  It is ‘None’ by default but can be set to a
     string which is added to the exception’s traceback.

   - bpo-45947(5): Place pointers to dict and values immediately before
     GC header.  This reduces number of dependent memory loads to access
     either dict or values from 3 to 1.

   - bpo-45915(6): ‘is_valid_fd’ now uses faster ‘fcntl(fd, F_GETFD)’ on
     Linux, macOS, and Windows.

   - bpo-44530(7): Reverts a change to the ‘code.__new__’ *note audit
     event: 19b7. from an earlier prerelease.

   - bpo-42268(8): Fail the configure step if the selected compiler
     doesn’t support memory sanitizer.  Patch by Pablo Galindo

   - bpo-45711(9): The three values of ‘exc_info’ are now always
     consistent with each other.  In particular, the ‘type’ and
     ‘traceback’ fields are now derived from the exception instance.
     This impacts the return values of *note sys.exc_info(): 68d. and
     *note PyErr_GetExcInfo(): 775. if the exception instance is
     modified while the exception is handled, as well as *note
     PyErr_SetExcInfo(): 774, which now ignores the ‘type’ and
     ‘traceback’ arguments provided to it.

   - bpo-45727(10): Refine the custom syntax error that suggests that a
     comma may be missing to trigger only when the expressions are
     detected between parentheses or brackets.  Patch by Pablo Galindo

   - bpo-45885(11): Specialized the ‘COMPARE_OP’ opcode using the PEP
     659 machinery.

   - bpo-45786(12): Allocate space for the interpreter frame in the
     frame object, to avoid an additional allocation when the frame
     object outlives the frame activation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46009

   (2) https://bugs.python.org/issue?@action=redirect&bpo=46004

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45607

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45947

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45915

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44530

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42268

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45727

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45885

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45786


File: python.info,  Node: Library<80>,  Next: Core and Builtins<79>,  Prev: Core and Builtins<78>,  Up: Python 3 11 0 alpha 3

1.23.41.2 Library
.................

   - bpo-45614(1): Fix *note traceback: fe. display for exceptions with
     invalid module name.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45614


File: python.info,  Node: Core and Builtins<79>,  Next: Library<81>,  Prev: Library<80>,  Up: Python 3 11 0 alpha 3

1.23.41.3 Core and Builtins
...........................

   - bpo-45813(1): Fix crash when calling coro.cr_frame.clear() after
     coroutine has been freed.

   - bpo-45811(2): Improve the tokenizer errors when encountering
     invisible control characters in the parser.  Patch by Pablo Galindo

   - bpo-45848(3): Allow the parser to obtain error lines directly from
     encoded files.  Patch by Pablo Galindo

   - bpo-45709(4): Restore behavior from 3.10 when tracing an exception
     raised within a with statement.

   - bpo-44525(5): Adds new *note COPY_FREE_VARS: 701. opcode, to make
     copying of free variables from function to frame explicit.  Helps
     optimization of calls to Python function.

   - bpo-45829(6): Specialize *note BINARY_SUBSCR: 1851. for classes
     with a ‘__getitem__’ method implemented in Python

   - bpo-45826(7): Fixed a crash when calling ‘.with_traceback(None)’ on
     ‘NameError’.  This occurs internally in
     ‘unittest.TestCase.assertRaises()’.

   - bpo-45822(8): Fixed a bug in the parser that was causing it to not
     respect PEP 263(9) coding cookies when no flags are provided.
     Patch by Pablo Galindo

   - bpo-45820(10): Fix a segfault when the parser fails without reading
     any input.  Patch by Pablo Galindo

   - bpo-45636(11): Simplify the implementation of *note BINARY_OP: 709.
     by indexing into an array of function pointers (rather than
     switching on the oparg).

   - bpo-42540(12): Fix crash when *note os.fork(): 197. is called with
     an active non-default memory allocator.

   - bpo-45738(13): Fix computation of error location for invalid
     continuation characters in the parser.  Patch by Pablo Galindo.

   - bpo-45636(14): Remove an existing “fast path” for old-style string
     formatting, since it no longer appears to have any measurable
     impact.

   - bpo-45753(15): Make recursion checks a bit more efficient by
     tracking amount of calls left before overflow.

   - bpo-45773(16): Fix a compiler hang when attempting to optimize
     certain jump patterns.

   - bpo-45764(17): The parser now gives a better error message when
     leaving out the opening parenthesis ‘(’ after a ‘def’-statement:

          >>> def f:
            File "<stdin>", line 1
              def f:
                   ^
          SyntaxError: expected '('

   - bpo-45609(18): Specialized the ‘STORE_SUBSCR’ opcode using the PEP
     659 machinery.

   - bpo-45636(19): Replace all numeric ‘BINARY_*’ and ‘INPLACE_*’
     instructions with a single *note BINARY_OP: 709. implementation.

   - bpo-45582(20): Path calculation (known as ‘getpath’) has been
     reimplemented as a frozen Python module.  This should have no
     visible impact, but may affect calculation of all paths referenced
     in *note sys: d9. and *note sysconfig: db.

   - bpo-45450(21): Improve the syntax error message for parenthesized
     arguments.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45813

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45811

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45848

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45709

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44525

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45829

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45826

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45822

   (9) https://peps.python.org/pep-0263/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45820

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45636

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42540

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45738

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45636

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45753

   (16) https://bugs.python.org/issue?@action=redirect&bpo=45773

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45764

   (18) https://bugs.python.org/issue?@action=redirect&bpo=45609

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45636

   (20) https://bugs.python.org/issue?@action=redirect&bpo=45582

   (21) https://bugs.python.org/issue?@action=redirect&bpo=45450


File: python.info,  Node: Library<81>,  Next: Documentation<32>,  Prev: Core and Builtins<79>,  Up: Python 3 11 0 alpha 3

1.23.41.4 Library
.................

   - bpo-27946(1): Fix possible crash when getting an attribute of *note
     xml.etree.ElementTree.Element: 310. simultaneously with replacing
     the ‘attrib’ dict.

   - bpo-45711(2): Make *note asyncio: a. normalize exceptions as soon
     as they are captured with *note PyErr_Fetch(): 3f6, and before they
     are stored as an exc_info triplet.  This brings ‘asyncio’ in line
     with the rest of the codebase, where an exc_info triplet is always
     normalized.

   - bpo-23819(3): Replaced asserts with exceptions in asyncio, patch by
     Kumar Aditya.

   - bpo-13236(4): *note unittest.TextTestResult: 534. and *note
     unittest.TextTestRunner: 185a. flush now the output stream more
     often.

   - bpo-45917(5): Added *note math.exp2(): 663.:, which returns 2
     raised to the power of x.

   - bpo-37658(6): Fix issue when on certain conditions
     ‘asyncio.wait_for()’ may allow a coroutine to complete
     successfully, but fail to return the result, potentially causing
     memory leaks or other issues.

   - bpo-45876(7): Improve the accuracy of stdev() and pstdev() in the
     statistics module.  When the inputs are floats or fractions, the
     output is a correctly rounded float

   - bpo-44649(8): Handle dataclass(slots=True) with a field that has
     default a default value, but for which init=False.

   - bpo-45803(9): Added missing kw_only parameter to
     dataclasses.make_dataclass().

   - bpo-45837(10): The ‘turtle.RawTurtle.settiltangle()’ is deprecated
     since Python 3.1, it now emits a deprecation warning and will be
     removed in Python 3.13.

     Use ‘turtle.RawTurtle.tiltangle()’ instead.

     ‘turtle.RawTurtle.tiltangle()’ was earlier incorrectly marked as
     deprecated, its docstring has been corrected.

     Patch by Hugo van Kemenade.

   - bpo-45831(11): *note faulthandler: 58. can now write ASCII-only
     strings (like filenames and function names) with a single write()
     syscall when dumping a traceback.  It reduces the risk of getting
     an unreadable dump when two threads or two processes dump a
     traceback to the same file (like stderr) at the same time.  Patch
     by Victor Stinner.

   - bpo-45828(12): ‘sqlite’ C callbacks now use unraisable exceptions
     if callback tracebacks are enabled.  Patch by Erlend E. Aasland.

   - bpo-41735(13): Fix thread lock in ‘zlib.Decompress.flush()’ method
     before ‘PyObject_GetBuffer’.

   - bpo-45235(14): Reverted an argparse bugfix that caused regression
     in the handling of default arguments for subparsers.  This
     prevented leaf level arguments from taking precedence over root
     level arguments.

   - bpo-45754(15): Fix a regression in Python 3.11a1 and 3.11a2 where
     *note sqlite3: cf. incorrectly would use ‘SQLITE_LIMIT_LENGTH’ when
     checking SQL statement lengths.  Now, ‘SQLITE_LIMIT_SQL_LENGTH’ is
     used.  Patch by Erlend E. Aasland.

   - bpo-45766(16): Added 'proportional' option to *note
     statistics.linear_regression(): 837.

   - bpo-45765(17): In importlib.metadata, fix distribution discovery
     for an empty path.

   - bpo-45757(18): Fix bug where *note dis: 38. produced an incorrect
     oparg when *note EXTENDED_ARG: 18c1. is followed by an opcode that
     does not use its argument.

   - bpo-45644(19): In-place JSON file formatting using ‘python3 -m
     json.tool infile infile’ now works correctly, previously it left
     the file empty.  Patch by Chris Wesseling.

   - bpo-45703(20): When a namespace package is imported before another
     module from the same namespace is created/installed in a different
     *note sys.path: 3b7. location while the program is running, calling
     the *note importlib.invalidate_caches(): c30. function will now
     also guarantee the new module is noticed.

   - bpo-45535(21): Improve output of ‘dir()’ with Enums.

   - bpo-45664(22): Fix *note types.resolve_bases(): bba. and *note
     types.new_class(): 11a5. for *note types.GenericAlias: 7f0.
     instance as a base.

   - bpo-45663(23): Fix *note dataclasses.is_dataclass(): 19bb. for
     dataclasses which are subclasses of *note types.GenericAlias: 7f0.

   - bpo-45662(24): Fix the repr of *note dataclasses.InitVar: 1959.
     with a type alias to the built-in class, e.g.
     ‘InitVar[list[int]]’.

   - bpo-43137(25): Launch GNOME web browsers via gio tool instead of
     obsolete gvfs-open

   - bpo-45429(26): On Windows, *note time.sleep(): 6a0. now uses a
     waitable timer which supports high-resolution timers.  Patch by
     Donghee Na and Eryk Sun.

   - bpo-37295(27): Optimize *note math.comb(): 6d3. and *note
     math.perm(): 6d4.

   - bpo-45514(28): Deprecated legacy functions in *note
     importlib.resources: 7b.

   - bpo-45507(29): Add tests for truncated/missing trailers in
     gzip.decompress implementation.

   - bpo-45359(30): Implement PEP 585(31) for *note
     graphlib.TopologicalSorter: 8ea.

   - bpo-44733(32): Add ‘max_tasks_per_child’ to *note
     concurrent.futures.ProcessPoolExecutor: 8f7.  This allows users to
     specify the maximum number of tasks a single process should execute
     before the process needs to be restarted.

   - bpo-28806(33): Improve netrc library.  netrc file no longer needs
     to contain all tokens.  And if the login name is anonymous,
     security check is no longer need.

   - bpo-43498(34): Avoid a possible '“RuntimeError: dictionary changed
     size during iteration”' when adjusting the process count of
     ‘ProcessPoolExecutor’.

   - bpo-42158(35): Add MIME types for N-quads, N-triples, Notation3 and
     TriG to ‘mimetypes’.

   - bpo-30533(36): Add *note inspect.getmembers_static(): 64c. , it
     return all members without triggering dynamic lookup via the
     descriptor protocol.  Patch by Weipeng Hong.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27946

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45711

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23819

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13236

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45917

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37658

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45876

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44649

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45803

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45837

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45831

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45828

   (13) https://bugs.python.org/issue?@action=redirect&bpo=41735

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45235

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45754

   (16) https://bugs.python.org/issue?@action=redirect&bpo=45766

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45765

   (18) https://bugs.python.org/issue?@action=redirect&bpo=45757

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45644

   (20) https://bugs.python.org/issue?@action=redirect&bpo=45703

   (21) https://bugs.python.org/issue?@action=redirect&bpo=45535

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45664

   (23) https://bugs.python.org/issue?@action=redirect&bpo=45663

   (24) https://bugs.python.org/issue?@action=redirect&bpo=45662

   (25) https://bugs.python.org/issue?@action=redirect&bpo=43137

   (26) https://bugs.python.org/issue?@action=redirect&bpo=45429

   (27) https://bugs.python.org/issue?@action=redirect&bpo=37295

   (28) https://bugs.python.org/issue?@action=redirect&bpo=45514

   (29) https://bugs.python.org/issue?@action=redirect&bpo=45507

   (30) https://bugs.python.org/issue?@action=redirect&bpo=45359

   (31) https://peps.python.org/pep-0585/

   (32) https://bugs.python.org/issue?@action=redirect&bpo=44733

   (33) https://bugs.python.org/issue?@action=redirect&bpo=28806

   (34) https://bugs.python.org/issue?@action=redirect&bpo=43498

   (35) https://bugs.python.org/issue?@action=redirect&bpo=42158

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30533


File: python.info,  Node: Documentation<32>,  Next: Tests<35>,  Prev: Library<81>,  Up: Python 3 11 0 alpha 3

1.23.41.5 Documentation
.......................

   - bpo-42238(1): ‘make -C Doc suspicious’ will be removed soon in
     favor of ‘make -C Doc check’, mark it as deprecated.

   - bpo-45840(2): Improve cross-references in the documentation for the
     data model.

   - bpo-45640(3): Properly marked-up grammar tokens in the
     documentation are now clickable and take you to the definition of a
     given piece of grammar.  Patch by Arthur Milchior.

   - bpo-45788(4): Link doc for sys.prefix to sysconfig doc on
     installation paths.

   - bpo-45772(5): ‘socket.socket’ documentation is corrected to a class
     from a function.

   - bpo-45392(6): Update the docstring of the *note type: d71. built-in
     to remove a redundant line and to mention keyword arguments for the
     constructor.

   - bpo-45250(7): Update the documentation to note that CPython does
     not consistently require iterators to define ‘__iter__’.

   - bpo-25381(8): In the extending chapter of the extending doc, update
     a paragraph about the global variables containing exception
     information.

   - bpo-43905(9): Expanded *note astuple(): 183e. and *note asdict():
     1836. docs, warning about deepcopy being applied and providing a
     workaround.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42238

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45840

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45640

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45788

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45772

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45392

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45250

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25381

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43905


File: python.info,  Node: Tests<35>,  Next: Build<39>,  Prev: Documentation<32>,  Up: Python 3 11 0 alpha 3

1.23.41.6 Tests
...............

   - bpo-45695(1): Out-of-tree builds with a read-only source directory
     are now tested by CI.

   - bpo-19460(2): Add new Test for
     ‘Lib/email/mime/nonmultipart.py::MIMENonMultipart’.

   - bpo-45835(3): Fix race condition in test_queue tests with multiple
     “feeder” threads.

   - bpo-45783(4): The test for the freeze tool now handles file moves
     and deletions.

   - bpo-45745(5): Remove the ‘--findleaks’ command line option of
     regrtest: use the ‘--fail-env-changed’ option instead.  Since
     Python 3.7, it was a deprecated alias to the ‘--fail-env-changed’
     option.

   - bpo-45701(6): Add tests with ‘tuple’ type with *note
     functools.lru_cache(): 9fa. to ‘test_functools’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45695

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19460

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45835

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45783

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45745

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45701


File: python.info,  Node: Build<39>,  Next: Windows<33>,  Prev: Tests<35>,  Up: Python 3 11 0 alpha 3

1.23.41.7 Build
...............

   - bpo-44035(1): CI now verifies that autoconf files have been
     regenerated with a current and unpatched autoconf package.

   - bpo-45950(2): The build system now uses a ‘_bootstrap_python’
     interpreter for freezing and deepfreezing again.  To speed up build
     process the build tools ‘_bootstrap_python’ and ‘_freeze_module’
     are no longer build with LTO.

   - bpo-45881(3): The ‘configure’ script now accepts
     ‘--with-build-python’ and ‘--with-freeze-module’ options to make
     cross compiling easier.

   - bpo-40280(4): Emscripten platform now uses ‘.wasm’ suffix by
     default.

   - bpo-40280(5): Disable unusable core extension modules on
     WASM/Emscripten targets.

   - bpo-40280(6): ‘configure’ now checks for socket ‘shutdown’
     function.  The check makes it possible to disable ‘SYS_shutdown’
     with ‘ac_cv_func_shutdown=no’ in CONFIG_SITE.

   - bpo-40280(7): ‘configure’ now checks for functions ‘fork1, getegid,
     geteuid, getgid, getppid, getuid, opendir, pipe, system, wait,
     ttyname’.

   - bpo-33393(8): Update ‘config.guess’ to 2021-06-03 and ‘config.sub’
     to 2021-08-14.  ‘Makefile’ now has an ‘update-config’ target to
     make updating more convenient.

   - bpo-45866(9): ‘make regen-all’ now produces the same output when
     run from a directory other than the source tree: when building
     Python out of the source tree.  pegen now strips directory of the
     “generated by pygen from <FILENAME>” header Patch by Victor
     Stinner.

   - bpo-40280(10): ‘configure’ now accepts machine ‘wasm32’ or ‘wasm64’
     and OS ‘wasi’ or ‘emscripten’ for cross building, e.g.
     ‘wasm32-unknown-emscripten’, ‘wasm32-wasi’, or
     ‘wasm32-unknown-wasi’.

   - bpo-41498(11): Python now compiles on platforms without ‘sigset_t’.
     Several functions in *note signal: c6. are not available when
     ‘sigset_t’ is missing.

     Based on patch by Roman Yurchak for pyodide.

   - bpo-45881(12): ‘setup.py’ now uses ‘CC’ from environment first to
     discover multiarch and cross compile paths.

   - bpo-45886(13): The ‘_freeze_module’ program path can now be
     overridden on the command line, e.g.  ‘make
     FREEZE_MODULE=../x86_64/Program/_freeze_module’.

   - bpo-45873(14): Get rid of the ‘_bootstrap_python’ build step.  The
     deepfreeze.py script is now run using ‘$(PYTHON_FOR_REGEN)’ which
     can be Python 3.7 or newer (on Windows, 3.8 or newer).

   - bpo-45847(15): Port builtin hashlib extensions to ‘PY_STDLIB_MOD’
     macro and ‘addext()’.

   - bpo-45723(16): Add ‘autoconf’ helpers for saving and restoring
     environment variables:

        * ‘SAVE_ENV’: Save ‘$CFLAGS’, ‘$LDFLAGS’, ‘$LIBS’, and
          ‘$CPPFLAGS’.

        * ‘RESTORE_ENV’: Restore ‘$CFLAGS’, ‘$LDFLAGS’, ‘$LIBS’, and
          ‘$CPPFLAGS’.

        * ‘WITH_SAVE_ENV([SCRIPT])’: Run ‘SCRIPT’ wrapped with
          ‘SAVE_ENV’ and ‘RESTORE_ENV’.

     Patch by Erlend E. Aasland.

   - bpo-45573(17): Mandatory core modules, that are required to
     bootstrap Python, are now in ‘Modules/Setup.bootstrap’.

   - bpo-45573(18): ‘configure’ now creates ‘Modules/Setup.stdlib’ with
     conditionally enabled/disabled extension module lines.  The file is
     not used, yet.

   - bpo-45573(19): ‘configure’ now uses a unified format to set state,
     compiler flags, and linker flags in Makefile.  The new macro
     ‘PY_STDLIB_MOD’ sets three variables that are consumed by
     ‘Modules/Setup’ and ‘setup.py’.

   - bpo-45816(20): Python now supports building with Visual Studio 2022
     (MSVC v143, VS Version 17.0).  Patch by Jeremiah Vivian.

   - bpo-45800(21): Settings for ‘pyexpat’ C extension are now detected
     by ‘configure’.  The bundled ‘expat’ library is built in
     ‘Makefile’.

   - bpo-45798(22): Settings for *note decimal: 36. internal C extension
     are now detected by ‘configure’.  The bundled ‘libmpdec’ library is
     built in ‘Makefile’.

   - bpo-45723(23): ‘configure’ has a new option ‘--with-pkg-config’ to
     disable or require pkg-config.

   - bpo-45774(24): The build dependencies for *note sqlite3: cf. are
     now detected by ‘configure’ and ‘pkg-config’.  Patch by Erlend E.
     Aasland.

   - bpo-45763(25): The build dependencies for *note zlib: 133, *note
     bz2: 13, and *note lzma: 8a. are now detected by ‘configure’.

   - bpo-45747(26): gdbm and dbm build dependencies are now detected by
     ‘configure’.

   - bpo-45743(27): On macOS, the build system no longer passes
     ‘search_paths_first’ to the linker.  The flag has been the default
     since Xcode 4 / macOS 10.6.

   - bpo-45723(28): ‘configure.ac’ is now compatible with autoconf 2.71.
     Deprecated checks ‘STDC_HEADERS’ and ‘AC_HEADER_TIME’ have been
     removed.

   - bpo-45723(29): ‘configure’ now prints a warning when pkg-config is
     missing.

   - bpo-45731(30): ‘configure --enable-loadable-sqlite-extensions’ is
     now handled by new ‘PY_SQLITE_ENABLE_LOAD_EXTENSION’ macro instead
     of logic in setup.py.

   - bpo-45723(31): configure.ac now uses custom helper macros and
     ‘AC_CACHE_CHECK’ to simplify and speed up configure runs.

   - bpo-45696(32): Skip the marshal step for frozen modules by
     generating C code that produces a set of ready-to-use code objects.
     This speeds up startup time by another 10% or more.

   - bpo-45561(33): Run smelly.py tool from $(srcdir).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44035

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45950

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45881

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33393

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45866

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40280

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41498

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45881

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45886

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45873

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45847

   (16) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45573

   (18) https://bugs.python.org/issue?@action=redirect&bpo=45573

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45573

   (20) https://bugs.python.org/issue?@action=redirect&bpo=45816

   (21) https://bugs.python.org/issue?@action=redirect&bpo=45800

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45798

   (23) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (24) https://bugs.python.org/issue?@action=redirect&bpo=45774

   (25) https://bugs.python.org/issue?@action=redirect&bpo=45763

   (26) https://bugs.python.org/issue?@action=redirect&bpo=45747

   (27) https://bugs.python.org/issue?@action=redirect&bpo=45743

   (28) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (29) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (30) https://bugs.python.org/issue?@action=redirect&bpo=45731

   (31) https://bugs.python.org/issue?@action=redirect&bpo=45723

   (32) https://bugs.python.org/issue?@action=redirect&bpo=45696

   (33) https://bugs.python.org/issue?@action=redirect&bpo=45561


File: python.info,  Node: Windows<33>,  Next: macOS<25>,  Prev: Build<39>,  Up: Python 3 11 0 alpha 3

1.23.41.8 Windows
.................

   - bpo-46105(1): Fixed calculation of *note sys.path: 3b7. in a venv
     on Windows.

   - bpo-45901(2): When installed through the Microsoft Store and set as
     the default app for ‘*.py’ files, command line arguments will now
     be passed to Python when invoking a script without explicitly
     launching Python (that is, ‘script.py args’ rather than ‘python
     script.py args’).

   - bpo-45616(3): Fix Python Launcher’s ability to distinguish between
     versions 3.1 and 3.10 when either one is explicitly requested.
     Previously, 3.1 would be used if 3.10 was requested but not
     installed, and 3.10 would be used if 3.1 was requested but 3.10 was
     installed.

   - bpo-45850(4): Implement changes to build with deep-frozen modules
     on Windows.  Note that we now require Python 3.10 as the
     “bootstrap” or “host” Python.

   - bpo-45732(5): Updates bundled Tcl/Tk to 8.6.12.

   - bpo-45720(6): Internal reference to ‘shlwapi.dll’ was dropped to
     help improve startup time.  This DLL will no longer be loaded at
     the start of every Python process.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=46105

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45901

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45616

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45850

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45732

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45720


File: python.info,  Node: macOS<25>,  Next: C API<34>,  Prev: Windows<33>,  Up: Python 3 11 0 alpha 3

1.23.41.9 macOS
...............

   - bpo-45732(1): Update python.org macOS installer to use Tcl/Tk
     8.6.12.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45732


File: python.info,  Node: C API<34>,  Prev: macOS<25>,  Up: Python 3 11 0 alpha 3

1.23.41.10 C API
................

   - bpo-39026(1): Fix Python.h to build C extensions with Xcode: remove
     a relative include from ‘Include/cpython/pystate.h’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39026


File: python.info,  Node: Python 3 11 0 alpha 2,  Next: Python 3 11 0 alpha 1,  Prev: Python 3 11 0 alpha 3,  Up: Changelog

1.23.42 Python 3.11.0 alpha 2
-----------------------------

'Release date: 2021-11-05'

* Menu:

* Core and Builtins: Core and Builtins<80>.
* Library: Library<82>.
* Documentation: Documentation<33>.
* Tests: Tests<36>.
* Build: Build<40>.
* Windows: Windows<34>.
* macOS: macOS<26>.
* IDLE: IDLE<22>.
* C API: C API<35>.


File: python.info,  Node: Core and Builtins<80>,  Next: Library<82>,  Up: Python 3 11 0 alpha 2

1.23.42.1 Core and Builtins
...........................

   - bpo-45716(1): Improve the *note SyntaxError: 18d. message when
     using ‘True’, ‘None’ or ‘False’ as keywords in a function call.
     Patch by Pablo Galindo.

   - bpo-45688(2): *note sys.stdlib_module_names: 847. now contains the
     macOS-specific module ‘_scproxy’.

   - bpo-45379(3): Clarify *note ImportError: 41c. message when we try
     to explicitly import a frozen module but frozen modules are
     disabled.

   - bpo-44525(4): Specialize simple calls to Python functions (no
     starargs, keyword dict, or closure)

   - bpo-45530(5): Cases of sorting using tuples as keys may now be
     significantly faster in some cases.  Patch by Tim Peters.

     The order of the result may differ from earlier releases if the
     tuple elements don’t define a total ordering (see *note Value
     comparisons: 19c4. for information on total ordering).  It’s
     generally true that the result of sorting simply isn’t well-defined
     in the absence of a total ordering on list elements.

   - bpo-45526(6): In obmalloc, set ADDRESS_BITS to not ignore any bits
     (ignored 16 before).  That is safer in the case that the kernel
     gives user-space virtual addresses that span a range greater than
     48 bits.

   - bpo-30570(7): Fixed a crash in ‘issubclass()’ from infinite
     recursion when searching pathological ‘__bases__’ tuples.

   - bpo-45521(8): Fix a bug in the obmalloc radix tree code.  On 64-bit
     machines, the bug causes the tree to hold 46-bits of virtual
     addresses, rather than the intended 48-bits.

   - bpo-45494(9): Fix parser crash when reporting errors involving
     invalid continuation characters.  Patch by Pablo Galindo.

   - bpo-45445(10): Python now fails to initialize if it finds an
     invalid *note -X: 176. option in the command line.  Patch by Pablo
     Galindo.

   - bpo-45340(11): Object attributes are held in an array instead of a
     dictionary.  An object’s dictionary are created lazily, only when
     needed.  Reduces the memory consumption of a typical Python object
     by about 30%.  Patch by Mark Shannon.

   - bpo-45408(12): Fix a crash in the parser when reporting tokenizer
     errors that occur at the same time unclosed parentheses are
     detected.  Patch by Pablo Galindo.

   - bpo-29410(13): Add SipHash13 for string hash algorithm and use it
     by default.

   - bpo-45385(14): Fix reference leak from descr_check.  Patch by
     Donghee Na.

   - bpo-45367(15): Specialized the ‘BINARY_MULTIPLY’ opcode to
     ‘BINARY_MULTIPLY_INT’ and ‘BINARY_MULTIPLY_FLOAT’ using the PEP 659
     machinery.

   - bpo-21736(16): Frozen stdlib modules now have ‘__file__’ to the .py
     file they would otherwise be loaded from, if possible.  For
     packages, ‘__path__’ now has the correct entry instead of being an
     empty list, which allows unfrozen submodules to be imported.  These
     are set only if the stdlib directory is known when the runtime is
     initialized.  Note that the file at ‘__file__’ is not guaranteed to
     exist.  None of this affects non-stdlib frozen modules nor, for
     now, frozen modules imported using ‘PyImport_ImportFrozenModule()’.
     Also, at the moment ‘co_filename’ is not updated for the module.

   - bpo-45020(17): For frozen stdlib modules, record the original
     module name as ‘module.__spec__.loader_state.origname’.  If the
     value is different than ‘module.__spec__.name’ then the module was
     defined as an alias in Tools/scripts/freeze_modules.py.  If it is
     ‘None’ then the module comes from a source file outside the stdlib.

   - bpo-45324(18): In FrozenImporter.find_spec(), we now preserve the
     information needed in exec_module() to load the module.  This
     change mostly impacts internal details, rather than changing the
     importer’s behavior.

   - bpo-45292(19): Implement PEP 654(20).  Add *note ExceptionGroup:
     1b6. and *note BaseExceptionGroup: 25f.  Update traceback display
     code.

   - bpo-40116(21): Change to the implementation of split dictionaries.
     Classes where the instances differ either in the exact set of
     attributes, or in the order in which those attributes are set, can
     still share keys.  This should have no observable effect on users
     of Python or the C-API. Patch by Mark Shannon.

   - bpo-44050(22): Extensions that indicate they use global state (by
     setting ‘m_size’ to -1) can again be used in multiple interpreters.
     This reverts to behavior of Python 3.8.

   - bpo-44525(23): Setup initial specialization infrastructure for the
     ‘CALL_FUNCTION’ opcode.  Implemented initial specializations for C
     function calls:

        * ‘CALL_FUNCTION_BUILTIN_O’ for ‘METH_O’ flag.

        * ‘CALL_FUNCTION_BUILTIN_FAST’ for ‘METH_FASTCALL’ flag without
          keywords.

        * ‘CALL_FUNCTION_LEN’ for ‘len(o)’.

        * ‘CALL_FUNCTION_ISINSTANCE’ for ‘isinstance(o, t)’.

   - bpo-44511(24): Improve the generated bytecode for class and mapping
     patterns.

   - bpo-43706(25): Speed up calls to ‘enumerate()’ by using the PEP
     590(26) ‘vectorcall’ calling convention.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45716

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45688

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45379

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44525

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45530

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45526

   (7) https://bugs.python.org/issue?@action=redirect&bpo=30570

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45521

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45494

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45445

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45340

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45408

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29410

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45385

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45367

   (16) https://bugs.python.org/issue?@action=redirect&bpo=21736

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45020

   (18) https://bugs.python.org/issue?@action=redirect&bpo=45324

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45292

   (20) https://peps.python.org/pep-0654/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40116

   (22) https://bugs.python.org/issue?@action=redirect&bpo=44050

   (23) https://bugs.python.org/issue?@action=redirect&bpo=44525

   (24) https://bugs.python.org/issue?@action=redirect&bpo=44511

   (25) https://bugs.python.org/issue?@action=redirect&bpo=43706

   (26) https://peps.python.org/pep-0590/


File: python.info,  Node: Library<82>,  Next: Documentation<33>,  Prev: Core and Builtins<80>,  Up: Python 3 11 0 alpha 2

1.23.42.2 Library
.................

   - bpo-45679(1): Fix caching of multi-value *note typing.Literal: 85b.
     ‘Literal[True, 2]’ is no longer equal to ‘Literal[1, 2]’.

   - bpo-42064(2): Convert *note sqlite3: cf. to multi-phase
     initialisation (PEP 489).  Patches by Erlend E. Aasland.

   - bpo-45438(3): Fix typing.Signature string representation for
     generic builtin types.

   - bpo-45613(4): *note sqlite3: cf. now sets *note
     sqlite3.threadsafety: 67f. based on the default threading mode the
     underlying SQLite library has been compiled with.  Patch by Erlend
     E. Aasland.

   - bpo-45574(5): Fix warning about ‘print_escape’ being unused.

   - bpo-45581(6): *note sqlite3.connect(): 2a8. now correctly raises
     *note MemoryError: 15ab. if the underlying SQLite API signals
     memory error.  Patch by Erlend E. Aasland.

   - bpo-45557(7): *note pprint.pprint(): 82e. now handles
     'underscore_numbers' correctly.  Previously it was always setting
     it to ‘False’.

   - bpo-44019(8): Add *note operator.call(): 19c6. to
     ‘operator.__all__’.  Patch by Kreusada.

   - bpo-42174(9): *note shutil.get_terminal_size(): 1147. now falls
     back to sane values if the column or line count are 0.

   - bpo-35673(10): Improve the introspectability of the ‘__loader__’
     attribute for namespace packages.  *note
     importlib.machinery.NamespaceLoader: f8f. is now public, and
     implements the *note importlib.abc.InspectLoader: f8d. interface.
     ‘_NamespaceLoader’ is kept for backward compatibility.

   - bpo-45515(11): Add references to *note zoneinfo: 134. in the *note
     datetime: 30. documentation, mostly replacing outdated references
     to ‘dateutil.tz’.  Change by Paul Ganssle.

   - bpo-45475(12): Reverted optimization of iterating *note
     gzip.GzipFile: 41d, *note bz2.BZ2File: 86d, and *note
     lzma.LZMAFile: 1047. (see bpo-43787(13)) because it caused
     regression when user iterate them without having reference of them.
     Patch by Inada Naoki.

   - bpo-45489(14): Update *note ForwardRef: 197f. to support ‘|’
     operator.  Patch by Donghee Na.

   - bpo-42222(15): Removed deprecated support for float arguments in
     'randrange()'.

   - bpo-45428(16): Fix a regression in py_compile when reading
     filenames from standard input.

   - bpo-45467(17): Fix incremental decoder and stream reader in the
     “raw-unicode-escape” codec.  Previously they failed if the escape
     sequence was split.

   - bpo-45461(18): Fix incremental decoder and stream reader in the
     “unicode-escape” codec.  Previously they failed if the escape
     sequence was split.

   - bpo-45239(19): Fixed *note email.utils.parsedate_tz(): 19c7.
     crashing with *note UnboundLocalError: 1586. on certain invalid
     input instead of returning ‘None’.  Patch by Ben Hoyt.

   - bpo-45417(20): Fix quadratic behaviour in the enum module: Creation
     of enum classes with a lot of entries was quadratic.

   - bpo-45249(21): Fix the behaviour of *note traceback.print_exc():
     19c8. when displaying the caret when the ‘end_offset’ in the
     exception is set to 0.  Patch by Pablo Galindo

   - bpo-45416(22): Fix use of *note asyncio.Condition: a82. with
     explicit *note asyncio.Lock: a80. objects, which was a regression
     due to removal of explicit loop arguments.  Patch by Joongi Kim.

   - bpo-20028(23): Empty escapechar/quotechar is not allowed when
     initializing *note csv.Dialect: 178e.  Patch by Vajrasky Kok and
     Donghee Na.

   - bpo-44904(24): Fix bug in the *note doctest: 3a. module that caused
     it to fail if a docstring included an example with a ‘classmethod’
     ‘property’.  Patch by Alex Waygood.

   - bpo-45406(25): Make *note inspect.getmodule(): 1913. catch
     ‘FileNotFoundError’ raised by ‘inspect.getabsfile()’, and return
     ‘None’ to indicate that the module could not be determined.

   - bpo-45411(26): Add extensions for files containing subtitles - .srt
     & .vtt - to the mimetypes.py module.

   - bpo-10716(27): Migrated pydoc to HTML5 (without changing the look
     of it).  Side effect is to update xmlrpc’s ‘ServerHTMLDoc’ which
     now uses the CSS too.  cgitb now relies less on pydoc (as it can’t
     use the CSS file).

   - bpo-27580(28): Add support of null characters in *note csv: 29.

   - bpo-45262(29): Prevent use-after-free in asyncio.  Make sure the
     cached running loop holder gets cleared on dealloc to prevent
     use-after-free in get_running_loop

   - bpo-45386(30): Make *note xmlrpc.client: 12e. more robust to C
     runtimes where the underlying C ‘strftime’ function results in a
     ‘ValueError’ when testing for year formatting options.

   - bpo-20028(31): Improve error message of *note csv.Dialect: 178e.
     when initializing.  Patch by Vajrasky Kok and Donghee Na.

   - bpo-45343(32): Update bundled pip to 21.2.4 and setuptools to
     58.1.0

   - bpo-45328(33): Fixed *note http.client.HTTPConnection: b59. to work
     properly in OSs that don’t support the ‘TCP_NODELAY’ socket option.

   - bpo-45243(34): Add *note setlimit(): 67d. and *note getlimit():
     67e. to *note sqlite3.Connection: 245. for setting and getting
     SQLite limits by connection basis.  Patch by Erlend E. Aasland.

   - bpo-45320(35): Removed from the *note inspect: 7e. module:

        * 
          the ‘getargspec’ function, deprecated since Python 3.0;

               use *note inspect.signature(): 73b. or *note
               inspect.getfullargspec(): 73c. instead.

        * the ‘formatargspec’ function, deprecated since Python 3.5; use
          the *note inspect.signature(): 73b. function and ‘Signature’
          object directly.

        * the undocumented ‘Signature.from_builtin’ and
          ‘Signature.from_function’ functions, deprecated since Python
          3.5; use the *note Signature.from_callable(): 73d. method
          instead.

     Patch by Hugo van Kemenade.

   - bpo-45192(36): Fix the ‘tempfile._infer_return_type’ function so
     that the ‘dir’ argument of the *note tempfile: e0. functions
     accepts an object implementing the ‘os.PathLike’ protocol.

     Patch by Kyungmin Lee.

   - bpo-45160(37): When tracing a tkinter variable used by a ttk
     OptionMenu, callbacks are no longer made twice.

   - bpo-25625(38): Added non parallel-safe *note chdir(): 60f. context
     manager to change the current working directory and then restore it
     on exit.  Simple wrapper around *note chdir(): 610.

   - bpo-24139(39): Add support for SQLite extended result codes in
     *note sqlite3.Error: 19c9.  Patch by Erlend E. Aasland.

   - bpo-24444(40): Fixed an error raised in *note argparse: 6. help
     display when help for an option is set to 1+ blank spaces or when
     'choices' arg is an empty container.

   - bpo-44547(41): Implement ‘Fraction.__int__’, so that a *note
     fractions.Fraction: 1e7. instance ‘f’ passes an ‘isinstance(f,
     typing.SupportsInt)’ check.

   - bpo-40321(42): Adds support for HTTP 308 redirects to *note urllib:
     108.  See RFC 7538(43) for details.  Patch by Jochem
     Schulenklopper.

   - bpo-41374(44): Ensure that ‘socket.TCP_*’ constants are exposed on
     Cygwin 3.1.6 and greater.

   - bpo-35970(45): Add help flag to the base64 module’s command line
     interface.  Patch contributed by Robert Kuska.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45679

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42064

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45438

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45613

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45574

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45581

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45557

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44019

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42174

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35673

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45515

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45475

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43787

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45489

   (15) https://bugs.python.org/issue?@action=redirect&bpo=42222

   (16) https://bugs.python.org/issue?@action=redirect&bpo=45428

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45467

   (18) https://bugs.python.org/issue?@action=redirect&bpo=45461

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45239

   (20) https://bugs.python.org/issue?@action=redirect&bpo=45417

   (21) https://bugs.python.org/issue?@action=redirect&bpo=45249

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45416

   (23) https://bugs.python.org/issue?@action=redirect&bpo=20028

   (24) https://bugs.python.org/issue?@action=redirect&bpo=44904

   (25) https://bugs.python.org/issue?@action=redirect&bpo=45406

   (26) https://bugs.python.org/issue?@action=redirect&bpo=45411

   (27) https://bugs.python.org/issue?@action=redirect&bpo=10716

   (28) https://bugs.python.org/issue?@action=redirect&bpo=27580

   (29) https://bugs.python.org/issue?@action=redirect&bpo=45262

   (30) https://bugs.python.org/issue?@action=redirect&bpo=45386

   (31) https://bugs.python.org/issue?@action=redirect&bpo=20028

   (32) https://bugs.python.org/issue?@action=redirect&bpo=45343

   (33) https://bugs.python.org/issue?@action=redirect&bpo=45328

   (34) https://bugs.python.org/issue?@action=redirect&bpo=45243

   (35) https://bugs.python.org/issue?@action=redirect&bpo=45320

   (36) https://bugs.python.org/issue?@action=redirect&bpo=45192

   (37) https://bugs.python.org/issue?@action=redirect&bpo=45160

   (38) https://bugs.python.org/issue?@action=redirect&bpo=25625

   (39) https://bugs.python.org/issue?@action=redirect&bpo=24139

   (40) https://bugs.python.org/issue?@action=redirect&bpo=24444

   (41) https://bugs.python.org/issue?@action=redirect&bpo=44547

   (42) https://bugs.python.org/issue?@action=redirect&bpo=40321

   (43) https://datatracker.ietf.org/doc/html/rfc7538.html

   (44) https://bugs.python.org/issue?@action=redirect&bpo=41374

   (45) https://bugs.python.org/issue?@action=redirect&bpo=35970


File: python.info,  Node: Documentation<33>,  Next: Tests<36>,  Prev: Library<82>,  Up: Python 3 11 0 alpha 2

1.23.42.3 Documentation
.......................

   - bpo-45726(1): Improve documentation for *note
     functools.singledispatch(): 63c. and *note
     functools.singledispatchmethod: 9fb.

   - bpo-45680(2): Amend the docs on ‘GenericAlias’ objects to clarify
     that non-container classes can also implement ‘__class_getitem__’.
     Patch contributed by Alex Waygood.

   - bpo-45618(3): Update Sphinx version used to build the documentation
     to 4.2.0.  Patch by Maciej Olko.

   - bpo-45655(4): Add a new “relevant PEPs” section to the top of the
     documentation for the ‘typing’ module.  Patch by Alex Waygood.

   - bpo-45604(5): Add ‘level’ argument to
     ‘multiprocessing.log_to_stderr’ function docs.

   - bpo-45516(6): Add protocol description to the *note
     importlib.abc.TraversableResources: 19cb. documentation.

   - bpo-45464(7): Mention in the documentation of *note Built-in
     Exceptions: 19cc. that inheriting from multiple exception types in
     a single subclass is not recommended due to possible memory layout
     incompatibility.

   - bpo-45449(8): Add note about PEP 585(9) in *note collections.abc:
     1e.

   - bpo-45516(10): Add protocol description to the *note
     importlib.abc.Traversable: 19cd. documentation.

   - bpo-20692(11): Add Programming FAQ entry explaining that int
     literal attribute access requires either a space after or
     parentheses around the literal.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45726

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45680

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45618

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45655

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45604

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45516

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45464

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45449

   (9) https://peps.python.org/pep-0585/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45516

   (11) https://bugs.python.org/issue?@action=redirect&bpo=20692


File: python.info,  Node: Tests<36>,  Next: Build<40>,  Prev: Documentation<33>,  Up: Python 3 11 0 alpha 2

1.23.42.4 Tests
...............

   - bpo-45678(1): Add tests for scenarios in which *note
     functools.singledispatchmethod: 9fb. is stacked on top of a method
     that has already been wrapped by two other decorators.  Patch by
     Alex Waygood.

   - bpo-45578(2): Add tests for *note dis.distb(): f64.

   - bpo-45678(3): Add tests to ensure that
     ‘functools.singledispatchmethod’ correctly wraps the attributes of
     the target function.

   - bpo-45668(4): PGO tests now pass when Python is built without test
     extension modules.

   - bpo-45577(5): Add subtests for all ‘pickle’ protocols in
     ‘test_zoneinfo’.

   - bpo-45566(6): Fix ‘test_frozen_pickle’ in ‘test_dataclasses’ to
     check all ‘pickle’ versions.

   - bpo-43592(7): ‘test.libregrtest’ now raises the soft resource limit
     for the maximum number of file descriptors when the default is too
     low for our test suite as was often the case on macOS.

   - bpo-39679(8): Add more test cases for
     ‘@functools.singledispatchmethod’ when combined with ‘@classmethod’
     or ‘@staticmethod’.

   - bpo-45410(9): When libregrtest spawns a worker process, stderr is
     now written into stdout to keep messages order.  Use a single pipe
     for stdout and stderr, rather than two pipes.  Previously, messages
     were out of order which made analysis of buildbot logs harder Patch
     by Victor Stinner.

   - bpo-45402(10): Fix test_tools.test_sundry() when Python is built
     out of tree: fix how the freeze_modules.py tool locates the
     _freeze_module program.  Patch by Victor Stinner.

   - bpo-45403(11): Fix test_sys.test_stdlib_dir() when Python is built
     outside the source tree: compare normalized paths.  Patch by Victor
     Stinner.

   - bpo-45400(12): Fix
     test_name_error_suggestions_do_not_trigger_for_too_many_locals() of
     test_exceptions if a directory name contains “a1” (like
     “Python-3.11.0a1”): use a stricter regular expression.  Patch by
     Victor Stinner.

   - bpo-10572(13): Rename *note sqlite3: cf. tests from ‘test_sqlite’
     to ‘test_sqlite3’, and relocate them to ‘Lib/test/test_sqlite3’.
     Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45678

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45578

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45678

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45668

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45577

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45566

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43592

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39679

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45410

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45402

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45403

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45400

   (13) https://bugs.python.org/issue?@action=redirect&bpo=10572


File: python.info,  Node: Build<40>,  Next: Windows<34>,  Prev: Tests<36>,  Up: Python 3 11 0 alpha 2

1.23.42.5 Build
...............

   - bpo-43158(1): ‘setup.py’ now uses values from configure script to
     build the ‘_uuid’ extension module.  Configure now detects
     util-linux’s ‘libuuid’, too.

   - bpo-45666(2): Fix warning of ‘swprintf’ and ‘%s’ usage in
     ‘_testembed.c’

   - bpo-45548(3): ‘Modules/Setup’ and ‘Modules/makesetup’ have been
     improved.  The ‘Setup’ file now contains working rules for all
     extensions.  Outdated comments have been removed.  Rules defined by
     ‘makesetup’ track dependencies correctly.

   - bpo-45548(4): The *note math: 8e. and *note cmath: 18.
     implementation now require a C99 compatible ‘libm’ and no longer
     ship with workarounds for missing acosh, asinh, atanh, expm1, and
     log1p functions.

   - bpo-45595(5): ‘setup.py’ and ‘makesetup’ now track build
     dependencies on all Python header files and module specific header
     files.

   - bpo-45571(6): ‘Modules/Setup’ now use ‘PY_CFLAGS_NODIST’ instead of
     ‘PY_CFLAGS’ to compile shared modules.

   - bpo-45570(7): ‘pyexpat’ and ‘_elementtree’ no longer define
     obsolete macros ‘HAVE_EXPAT_CONFIG_H’ and ‘USE_PYEXPAT_CAPI’.
     ‘XML_POOR_ENTROPY’ is now defined in ‘expat_config.h’.

   - bpo-43974(8): ‘setup.py’ no longer defines ‘Py_BUILD_CORE_MODULE’.
     Instead every module, that uses the internal API, defines the
     macro.

   - bpo-45548(9): Fill in missing entries in Modules/Setup.

   - bpo-45532(10): Update *note sys.version: 178. to use ‘main’ as
     fallback information.  Patch by Jeong YunWon.

   - bpo-45536(11): The ‘configure’ script now checks whether OpenSSL
     headers and libraries provide required APIs.  Most common APIs are
     verified.  The check detects outdated or missing OpenSSL. Failures
     do not stop configure.

   - bpo-45221(12): Fixed regression in handling of ‘LDFLAGS’ and
     ‘CPPFLAGS’ options where ‘argparse.parse_known_args()’ could
     interpret an option as one of the built-in command line argument,
     for example ‘-h’ for help.

   - bpo-45440(13): Building Python now requires a C99 ‘<math.h>’ header
     file providing the following functions: ‘copysign()’, ‘hypot()’,
     ‘isfinite()’, ‘isinf()’, ‘isnan()’, ‘round()’.  Patch by Victor
     Stinner.

   - bpo-45405(14): Prevent ‘internal configure error’ when running
     ‘configure’ with recent versions of non-Apple clang.  Patch by
     David Bohman.

   - bpo-45433(15): Avoid linking libpython with libcrypt.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43158

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45666

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45548

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45548

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45595

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45571

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45570

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43974

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45548

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45532

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45536

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45221

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45440

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45405

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45433


File: python.info,  Node: Windows<34>,  Next: macOS<26>,  Prev: Build<40>,  Up: Python 3 11 0 alpha 2

1.23.42.6 Windows
.................

   - bpo-43652(1): Update Tcl/Tk to 8.6.11, actually this time.  The
     previous update incorrectly included 8.6.10.

   - bpo-45337(2): venv now warns when the created environment may need
     to be accessed at a different path, due to redirections, links or
     junctions.  It also now correctly installs or upgrades components
     when the alternate path is required.

   - bpo-43851(3): Build SQLite ‘SQLITE_OMIT_AUTOINIT’ on Windows.
     Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43652

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45337

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43851


File: python.info,  Node: macOS<26>,  Next: IDLE<22>,  Prev: Windows<34>,  Up: Python 3 11 0 alpha 2

1.23.42.7 macOS
...............

   - bpo-44828(1): Avoid tkinter file dialog failure on macOS 12
     Monterey when using the Tk 8.6.11 provided by python.org macOS
     installers.  Patch by Marc Culler of the Tk project.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44828


File: python.info,  Node: IDLE<22>,  Next: C API<35>,  Prev: macOS<26>,  Up: Python 3 11 0 alpha 2

1.23.42.8 IDLE
..............

   - bpo-45495(1): Add context keywords ‘case’ and ‘match’ to
     completions list.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45495


File: python.info,  Node: C API<35>,  Prev: IDLE<22>,  Up: Python 3 11 0 alpha 2

1.23.42.9 C API
...............

   - bpo-29103(1): *note PyType_FromSpec*: 554. now copies the class
     name from the spec to a buffer owned by the class, so the original
     can be safely deallocated.  Patch by Petr Viktorin.

   - bpo-45522(2): The internal freelists for frame, float, list, dict,
     async generators, and context objects can now be disabled.

   - bpo-35134(3): Exclude *note PyWeakref_GET_OBJECT(): 3c2. from the
     limited C API. It never worked since the ‘PyWeakReference’
     structure is opaque in the limited C API.

   - bpo-35081(4): Move the ‘interpreteridobject.h’ header file from
     ‘Include/’ to ‘Include/internal/’.  It only provides private
     functions.  Patch by Victor Stinner.

   - bpo-35134(5): The non-limited API files ‘cellobject.h’,
     ‘classobject.h’, ‘context.h’, ‘funcobject.h’, ‘genobject.h’ and
     ‘longintrepr.h’ have been moved to the ‘Include/cpython’ directory.
     Moreover, the ‘eval.h’ header file was removed.  These files must
     not be included directly, as they are already included in
     ‘Python.h’: *note Include Files: 787.  If they have been included
     directly, consider including ‘Python.h’ instead.  Patch by Victor
     Stinner.

   - bpo-45474(6): The following items are no longer available when
     ‘Py_LIMITED_API’ is defined:

        * *note PyMarshal_WriteLongToFile(): 799.

        * *note PyMarshal_WriteObjectToFile(): 79a.

        * *note PyMarshal_ReadObjectFromString(): 79b.

        * *note PyMarshal_WriteObjectToString(): 79c.

        * the ‘Py_MARSHAL_VERSION’ macro

     These are not part of the *note limited API: 79d.

     Patch by Victor Stinner.

   - bpo-45434(7): Remove the ‘pystrhex.h’ header file.  It only
     contains private functions.  C extensions should only include the
     main ‘<Python.h>’ header file.  Patch by Victor Stinner.

   - bpo-45440(8): Remove the ‘Py_FORCE_DOUBLE()’ macro.  It was used by
     the ‘Py_IS_INFINITY()’ macro.  Patch by Victor Stinner.

   - bpo-45434(9): ‘<Python.h>’ no longer includes the header files
     ‘<stdlib.h>’, ‘<stdio.h>’, ‘<errno.h>’ and ‘<string.h>’ when the
     ‘Py_LIMITED_API’ macro is set to ‘0x030b0000’ (Python 3.11) or
     higher.  C extensions should explicitly include the header files
     after ‘#include <Python.h>’.  Patch by Victor Stinner.

   - bpo-41123(10): Remove ‘Py_UNICODE_COPY()’ and ‘Py_UNICODE_FILL()’
     macros, deprecated since Python 3.3.  Use
     ‘PyUnicode_CopyCharacters()’ or ‘memcpy()’ (‘wchar_t*’ string), and
     ‘PyUnicode_Fill()’ functions instead.  Patch by Victor Stinner.

   - bpo-45412(11): Remove the following math macros using the ‘errno’
     variable:

        * ‘Py_ADJUST_ERANGE1()’

        * ‘Py_ADJUST_ERANGE2()’

        * ‘Py_OVERFLOWED()’

        * ‘Py_SET_ERANGE_IF_OVERFLOW()’

        * ‘Py_SET_ERRNO_ON_MATH_ERROR()’

     Patch by Victor Stinner.

   - bpo-45395(12): Custom frozen modules (the array set to
     ‘PyImport_FrozenModules’) are now treated as additions, rather than
     replacing all the default frozen modules.  Frozen stdlib modules
     can still be disabled by setting the “code” field of the custom
     array entry to NULL.

   - bpo-43760(13): Add new *note PyThreadState_EnterTracing(): 757, and
     *note PyThreadState_LeaveTracing(): 758. functions to the limited C
     API to suspend and resume tracing and profiling.  Patch by Victor
     Stinner.

   - bpo-44220(14): *note PyStructSequence_UnnamedField: 98c. is added
     to the Stable ABI.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29103

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45522

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45474

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45434

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45440

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45434

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45412

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45395

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43760

   (14) https://bugs.python.org/issue?@action=redirect&bpo=44220


File: python.info,  Node: Python 3 11 0 alpha 1,  Next: Python 3 10 0 beta 1,  Prev: Python 3 11 0 alpha 2,  Up: Changelog

1.23.43 Python 3.11.0 alpha 1
-----------------------------

'Release date: 2021-10-05'

* Menu:

* Security: Security<26>.
* Core and Builtins: Core and Builtins<81>.
* Library: Library<83>.
* Core and Builtins: Core and Builtins<82>.
* Library: Library<84>.
* Core and Builtins: Core and Builtins<83>.
* Library: Library<85>.
* Core and Builtins: Core and Builtins<84>.
* Library: Library<86>.
* Core and Builtins: Core and Builtins<85>.
* Library: Library<87>.
* Core and Builtins: Core and Builtins<86>.
* Library: Library<88>.
* Core and Builtins: Core and Builtins<87>.
* Library: Library<89>.
* Core and Builtins: Core and Builtins<88>.
* Library: Library<90>.
* Core and Builtins: Core and Builtins<89>.
* Library: Library<91>.
* Core and Builtins: Core and Builtins<90>.
* Library: Library<92>.
* Documentation: Documentation<34>.
* Tests: Tests<37>.
* Build: Build<41>.
* Windows: Windows<35>.
* macOS: macOS<27>.
* IDLE: IDLE<23>.
* Tools/Demos: Tools/Demos<20>.
* C API: C API<36>.


File: python.info,  Node: Security<26>,  Next: Core and Builtins<81>,  Up: Python 3 11 0 alpha 1

1.23.43.1 Security
..................

   - bpo-42278(1): Replaced usage of *note tempfile.mktemp(): 19d6. with
     *note TemporaryDirectory: 127a. to avoid a potential race
     condition.

   - bpo-44600(2): Fix incorrect line numbers while tracing some failed
     patterns in *note match: 813. statements.  Patch by Charles
     Burkland.

   - bpo-41180(3): Add auditing events to the *note marshal: 8d. module,
     and stop raising ‘code.__init__’ events for every unmarshalled code
     object.  Directly instantiated code objects will continue to raise
     an event, and audit event handlers should inspect or collect the
     raw marshal data.  This reduces a significant performance overhead
     when loading from ‘.pyc’ files.

   - bpo-44394(4): Update the vendored copy of libexpat to 2.4.1 (from
     2.2.8) to get the fix for the CVE 2013-0340(5) “Billion Laughs”
     vulnerability.  This copy is most used on Windows and macOS.

   - bpo-43124(6): Made the internal ‘putcmd’ function in *note smtplib:
     ca. sanitize input for presence of ‘\r’ and ‘\n’ characters to
     avoid (unlikely) command injection.

   - bpo-44022(7): *note http.client: 6f. now avoids infinitely reading
     potential HTTP headers after a ‘100 Continue’ status response from
     the server.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42278

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44600

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41180

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44394

   (5) https://www.cve.org/CVERecord?id=CVE-2013-0340

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43124

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44022


File: python.info,  Node: Core and Builtins<81>,  Next: Library<83>,  Prev: Security<26>,  Up: Python 3 11 0 alpha 1

1.23.43.2 Core and Builtins
...........................

   - bpo-43760(1): The number of hardware branches per instruction
     dispatch is reduced from two to one by adding a special instruction
     for tracing.  Patch by Mark Shannon.

   - bpo-45061(2): Add a deallocator to the bool type to detect refcount
     bugs in C extensions which call Py_DECREF(Py_True) or
     Py_DECREF(Py_False) by mistake.  Detect also refcount bugs when the
     empty tuple singleton or the Unicode empty string singleton is
     destroyed by mistake.  Patch by Victor Stinner.

   - bpo-24076(3): sum() was further optimised for summing up single
     digit integers.

   - bpo-45190(4): Update Unicode databases to Unicode 14.0.0.

   - bpo-45167(5): Fix deepcopying of *note types.GenericAlias: 7f0.
     objects.

   - bpo-45155(6): *note int.to_bytes(): 19d8. and *note
     int.from_bytes(): 198d. now take a default value of ‘"big"’ for the
     ‘byteorder’ argument.  ‘int.to_bytes()’ also takes a default value
     of ‘1’ for the ‘length’ argument.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43760

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45061

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24076

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45190

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45167

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45155


File: python.info,  Node: Library<83>,  Next: Core and Builtins<82>,  Prev: Core and Builtins<81>,  Up: Python 3 11 0 alpha 1

1.23.43.3 Library
.................

   - bpo-44219(1): Release the GIL while performing ‘isatty’ system
     calls on arbitrary file descriptors.  In particular, this affects
     *note os.isatty(): 19da, *note os.device_encoding(): 19db. and
     *note io.TextIOWrapper: 7bf.  By extension, *note io.open(): 520.
     in text mode is also affected.  This change solves a deadlock in
     ‘os.isatty()’.  Patch by Vincent Michel in bpo-44219(2).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44219

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44219


File: python.info,  Node: Core and Builtins<82>,  Next: Library<84>,  Prev: Library<83>,  Up: Python 3 11 0 alpha 1

1.23.43.4 Core and Builtins
...........................

   - bpo-44959(1): Added fallback to extension modules with ‘.sl’ suffix
     on HP-UX

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44959


File: python.info,  Node: Library<84>,  Next: Core and Builtins<83>,  Prev: Core and Builtins<82>,  Up: Python 3 11 0 alpha 1

1.23.43.5 Library
.................

   - bpo-45121(1): Fix issue where ‘Protocol.__init__’ raises
     ‘RecursionError’ when it’s called directly or via ‘super()’.  Patch
     provided by Yurii Karabas.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45121


File: python.info,  Node: Core and Builtins<83>,  Next: Library<85>,  Prev: Library<84>,  Up: Python 3 11 0 alpha 1

1.23.43.6 Core and Builtins
...........................

   - bpo-44348(1): The deallocator function of the *note BaseException:
     5be. type now uses the trashcan mechanism to prevent stack
     overflow.  For example, when a *note RecursionError: d96. instance
     is raised, it can be linked to another RecursionError through the
     ‘__context__’ attribute or the ‘__traceback__’ attribute, and then
     a chain of exceptions is created.  When the chain is destroyed,
     nested deallocator function calls can crash with a stack overflow
     if the chain is too long compared to the available stack memory.
     Patch by Victor Stinner.

   - bpo-45123(2): Fix PyAiter_Check to only check for the __anext__
     presence (not for __aiter__).  Rename PyAiter_Check to
     PyAIter_Check, PyObject_GetAiter -> PyObject_GetAIter.

   - bpo-1514420(3): Interpreter no longer attempts to open files with
     names in angle brackets (like “<string>” or “<stdin>”) when
     formatting an exception.

   - bpo-41031(4): Match C and Python code formatting of unprintable
     exceptions and exceptions in the *note __main__: 1. module.

   - bpo-37330(5): *note open(): 51f, *note io.open(): 520, *note
     codecs.open(): 743. and *note fileinput.FileInput: 73a. no longer
     accept ‘'U'’ (“universal newline”) in the file mode.  This flag was
     deprecated since Python 3.3.  Patch by Victor Stinner.

   - bpo-45083(6): When the interpreter renders an exception, its name
     now has a complete qualname.  Previously only the class name was
     concatenated to the module name, which sometimes resulted in an
     incorrect full name being displayed.

     (This issue impacted only the C code exception rendering, the *note
     traceback: fe. module was using qualname already).

   - bpo-34561(7): List sorting now uses the merge-ordering strategy
     from Munro and Wild’s ‘powersort()’.  Unlike the former strategy,
     this is provably near-optimal in the entropy of the distribution of
     run lengths.  Most uses of ‘list.sort()’ probably won’t see a
     significant time difference, but may see significant improvements
     in cases where the former strategy was exceptionally poor.
     However, as these are all fast linear-time approximations to a
     problem that’s inherently at best quadratic-time to solve truly
     optimally, it’s also possible to contrive cases where the former
     strategy did better.

   - bpo-45056(8): Compiler now removes trailing unused constants from
     co_consts.

   - bpo-45020(9): Add a new command line option, “-X
     frozen_modules=[on|off]” to opt out of (or into) using optional
     frozen modules.  This defaults to “on” (or “off” if it’s running
     out of the source tree).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44348

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45123

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1514420

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41031

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37330

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45083

   (7) https://bugs.python.org/issue?@action=redirect&bpo=34561

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45056

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45020


File: python.info,  Node: Library<85>,  Next: Core and Builtins<84>,  Prev: Core and Builtins<83>,  Up: Python 3 11 0 alpha 1

1.23.43.7 Library
.................

   - bpo-45012(1): In *note posix: ad, release GIL during ‘stat()’,
     ‘lstat()’, and ‘fstatat()’ syscalls made by *note
     os.DirEntry.stat(): 180a.  Patch by Stanisław Skonieczny.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45012


File: python.info,  Node: Core and Builtins<84>,  Next: Library<86>,  Prev: Library<85>,  Up: Python 3 11 0 alpha 1

1.23.43.8 Core and Builtins
...........................

   - bpo-45018(1): Fixed pickling of range iterators that iterated for
     over ‘2**32’ times.

   - bpo-45000(2): A *note SyntaxError: 18d. is now raised when trying
     to delete *note __debug__: 7de.  Patch by Donghee Na.

   - bpo-44963(3): Implement ‘send()’ and ‘throw()’ methods for
     ‘anext_awaitable’ objects.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45018

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45000

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44963


File: python.info,  Node: Library<86>,  Next: Core and Builtins<85>,  Prev: Core and Builtins<84>,  Up: Python 3 11 0 alpha 1

1.23.43.9 Library
.................

   - bpo-44962(1): Fix a race in WeakKeyDictionary, WeakValueDictionary
     and WeakSet when two threads attempt to commit the last pending
     removal.  This fixes asyncio.create_task and fixes a data loss in
     asyncio.run where shutdown_asyncgens is not run

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44962


File: python.info,  Node: Core and Builtins<85>,  Next: Library<87>,  Prev: Library<86>,  Up: Python 3 11 0 alpha 1

1.23.43.10 Core and Builtins
............................

   - bpo-24234(1): Implement the ‘__bytes__()’ special method on the
     *note bytes: 1c2. type, so a bytes object ‘b’ passes an
     ‘isinstance(b, typing.SupportsBytes)’ check.

   - bpo-24234(2): Implement the ‘__complex__()’ special method on the
     *note complex: 2f8. type, so a complex number ‘z’ passes an
     ‘isinstance(z, typing.SupportsComplex)’ check.

   - bpo-44954(3): Fixed a corner case bug where the result of
     ‘float.fromhex('0x.8p-1074')’ was rounded the wrong way.

   - bpo-44947(4): Refine the syntax error for trailing commas in import
     statements.  Patch by Pablo Galindo.

   - bpo-44945(5): Specialize the BINARY_ADD instruction using the PEP
     659 machinery.  Adds five new instructions:

        * BINARY_ADD_ADAPTIVE

        * BINARY_ADD_FLOAT

        * BINARY_ADD_INT

        * BINARY_ADD_UNICODE

        * BINARY_ADD_UNICODE_INPLACE_FAST

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24234

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24234

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44954

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44947

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44945


File: python.info,  Node: Library<87>,  Next: Core and Builtins<86>,  Prev: Core and Builtins<85>,  Up: Python 3 11 0 alpha 1

1.23.43.11 Library
..................

   - bpo-44929(1): Fix some edge cases of ‘enum.Flag’ string
     representation in the REPL. Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44929


File: python.info,  Node: Core and Builtins<86>,  Next: Library<88>,  Prev: Library<87>,  Up: Python 3 11 0 alpha 1

1.23.43.12 Core and Builtins
............................

   - bpo-44914(1): Class version tags are no longer recycled.

     This means that a version tag serves as a unique identifier for the
     state of a class.  We rely on this for effective specialization of
     the LOAD_ATTR and other instructions.

   - bpo-44698(2): Restore behaviour of complex exponentiation with
     integer-valued exponent of type *note float: 2f7. or *note complex:
     2f8.

   - bpo-44895(3): A debug variable *note PYTHONDUMPREFSFILE: 19e5. is
     added for creating a dump file which is generated by *note
     -with-trace-refs: 398.  Patch by Donghee Na.

   - bpo-44900(4): Add five superinstructions for PEP 659 quickening:

        * LOAD_FAST LOAD_FAST

        * STORE_FAST LOAD_FAST

        * LOAD_FAST LOAD_CONST

        * LOAD_CONST LOAD_FAST

        * STORE_FAST STORE_FAST

   - bpo-44889(5): Initial implementation of adaptive specialization of
     ‘LOAD_METHOD’.  The following specialized forms were added:

        * ‘LOAD_METHOD_CACHED’

        * ‘LOAD_METHOD_MODULE’

        * ‘LOAD_METHOD_CLASS’

   - bpo-44890(6): Specialization stats are always collected in debug
     builds.

   - bpo-44885(7): Correct the ast locations of f-strings with format
     specs and repeated expressions.  Patch by Pablo Galindo

   - bpo-44878(8): Remove the loop from the bytecode interpreter.  All
     instructions end with a DISPATCH macro, so the loop is now
     redundant.

   - bpo-44878(9): Remove switch statement for interpreter loop when
     using computed gotos.  This makes sure that we only have one
     dispatch table in the interpreter.

   - bpo-44874(10): Deprecate the old trashcan macros
     (‘Py_TRASHCAN_SAFE_BEGIN’/‘Py_TRASHCAN_SAFE_END’).  They should be
     replaced by the new macros ‘Py_TRASHCAN_BEGIN’ and
     ‘Py_TRASHCAN_END’.

   - bpo-44872(11): Use new trashcan macros (Py_TRASHCAN_BEGIN/END) in
     frameobject.c instead of the old ones (Py_TRASHCAN_SAFE_BEGIN/END).

   - bpo-33930(12): Fix segmentation fault with deep recursion when
     cleaning method objects.  Patch by Augusto Goulart and Pablo
     Galindo.

   - bpo-25782(13): Fix bug where ‘PyErr_SetObject’ hangs when the
     current exception has a cycle in its context chain.

   - bpo-44856(14): Fix reference leaks in the error paths of
     ‘update_bases()’ and ‘__build_class__’.  Patch by Pablo Galindo.

   - bpo-44826(15): Initial implementation of adaptive specialization of
     STORE_ATTR

     Three specialized forms of STORE_ATTR are added:

        * STORE_ATTR_SLOT

        * STORE_ATTR_SPLIT_KEYS

        * STORE_ATTR_WITH_HINT

   - bpo-44838(16): Fixed a bug that was causing the parser to raise an
     incorrect custom *note SyntaxError: 18d. for invalid ‘if’
     expressions.  Patch by Pablo Galindo.

   - bpo-44821(17): Create instance dictionaries (__dict__) eagerly, to
     improve regularity of object layout and assist specialization.

   - bpo-44792(18): Improve syntax errors for if expressions.  Patch by
     Miguel Brito

   - bpo-34013(19): Generalize the invalid legacy statement custom error
     message (like the one generated when “print” is called without
     parentheses) to include more generic expressions.  Patch by Pablo
     Galindo

   - bpo-44732(20): Rename ‘types.Union’ to ‘types.UnionType’.

   - bpo-44725(21): Expose specialization stats in python via
     ‘_opcode.get_specialization_stats()’.

   - bpo-44717(22): Improve AttributeError on circular imports of
     submodules.

   - bpo-44698(23): Fix undefined behaviour in complex object
     exponentiation.

   - bpo-44653(24): Support *note typing: 104. types in parameter
     substitution in the union type.

   - bpo-44676(25): Add ability to serialise ‘types.Union’ objects.
     Patch provided by Yurii Karabas.

   - bpo-44633(26): Parameter substitution of the union type with wrong
     types now raises ‘TypeError’ instead of returning *note
     NotImplemented: 7d6.

   - bpo-44661(27): Update ‘property_descr_set’ to use vectorcall if
     possible.  Patch by Donghee Na.

   - bpo-44662(28): Add ‘__module__’ to ‘types.Union’.  This also fixes
     ‘types.Union’ issues with ‘typing.Annotated’.  Patch provided by
     Yurii Karabas.

   - bpo-44655(29): Include the name of the type in unset __slots__
     attribute errors.  Patch by Pablo Galindo

   - bpo-44655(30): Don’t include a missing attribute with the same name
     as the failing one when offering suggestions for missing
     attributes.  Patch by Pablo Galindo

   - bpo-44646(31): Fix the hash of the union type: it no longer depends
     on the order of arguments.

   - bpo-44636(32): Collapse union of equal types.  E.g.  the result of
     ‘int | int’ is now ‘int’.  Fix comparison of the union type with
     non-hashable objects.  E.g.  ‘int | str == {}’ no longer raises a
     TypeError.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44914

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44698

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44895

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44900

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44889

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44890

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44885

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44878

   (9) https://bugs.python.org/issue?@action=redirect&bpo=44878

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44874

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44872

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33930

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25782

   (14) https://bugs.python.org/issue?@action=redirect&bpo=44856

   (15) https://bugs.python.org/issue?@action=redirect&bpo=44826

   (16) https://bugs.python.org/issue?@action=redirect&bpo=44838

   (17) https://bugs.python.org/issue?@action=redirect&bpo=44821

   (18) https://bugs.python.org/issue?@action=redirect&bpo=44792

   (19) https://bugs.python.org/issue?@action=redirect&bpo=34013

   (20) https://bugs.python.org/issue?@action=redirect&bpo=44732

   (21) https://bugs.python.org/issue?@action=redirect&bpo=44725

   (22) https://bugs.python.org/issue?@action=redirect&bpo=44717

   (23) https://bugs.python.org/issue?@action=redirect&bpo=44698

   (24) https://bugs.python.org/issue?@action=redirect&bpo=44653

   (25) https://bugs.python.org/issue?@action=redirect&bpo=44676

   (26) https://bugs.python.org/issue?@action=redirect&bpo=44633

   (27) https://bugs.python.org/issue?@action=redirect&bpo=44661

   (28) https://bugs.python.org/issue?@action=redirect&bpo=44662

   (29) https://bugs.python.org/issue?@action=redirect&bpo=44655

   (30) https://bugs.python.org/issue?@action=redirect&bpo=44655

   (31) https://bugs.python.org/issue?@action=redirect&bpo=44646

   (32) https://bugs.python.org/issue?@action=redirect&bpo=44636


File: python.info,  Node: Library<88>,  Next: Core and Builtins<87>,  Prev: Core and Builtins<86>,  Up: Python 3 11 0 alpha 1

1.23.43.13 Library
..................

   - bpo-44611(1): On Windows, *note os.urandom(): 526.: uses
     BCryptGenRandom API instead of CryptGenRandom API which is
     deprecated from Microsoft Windows API. Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44611


File: python.info,  Node: Core and Builtins<87>,  Next: Library<89>,  Prev: Library<88>,  Up: Python 3 11 0 alpha 1

1.23.43.14 Core and Builtins
............................

   - bpo-44635(1): Convert ‘None’ to ‘type(None)’ in the union type
     constructor.

   - bpo-26280(2): Implement adaptive specialization for BINARY_SUBSCR

     Three specialized forms of BINARY_SUBSCR are added:

        * BINARY_SUBSCR_LIST_INT

        * BINARY_SUBSCR_TUPLE_INT

        * BINARY_SUBSCR_DICT

   - bpo-44589(3): Mapping patterns in ‘match’ statements with two or
     more equal literal keys will now raise a *note SyntaxError: 18d. at
     compile-time.

   - bpo-44606(4): Fix ‘__instancecheck__’ and ‘__subclasscheck__’ for
     the union type.

   - bpo-42073(5): The ‘@classmethod’ decorator can now wrap other
     classmethod-like descriptors.

   - bpo-41972(6): Tuned the string-searching algorithm of fastsearch.h
     to have a shorter inner loop for most cases.

   - bpo-44590(7): All necessary data for executing a Python function
     (local variables, stack, etc) is now kept in a per-thread stack.
     Frame objects are lazily allocated on demand.  This increases
     performance by about 7% on the standard benchmark suite.
     Introspection and debugging are unaffected as frame objects are
     always available when needed.  Patch by Mark Shannon.

   - bpo-44584(8): The threading debug (‘PYTHONTHREADDEBUG’ environment
     variable) is deprecated in Python 3.10 and will be removed in
     Python 3.12.  This feature requires a debug build of Python.  Patch
     by Victor Stinner.

   - bpo-43895(9): An obsolete internal cache of shared object file
     handles added in 1995 that attempted, but did not guarantee, that a
     .so would not be dlopen’ed twice to work around flaws in mid-1990s
     posix-ish operating systems has been removed from dynload_shlib.c.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44635

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26280

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44589

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44606

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42073

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41972

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44590

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44584

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43895


File: python.info,  Node: Library<89>,  Next: Core and Builtins<88>,  Prev: Core and Builtins<87>,  Up: Python 3 11 0 alpha 1

1.23.43.15 Library
..................

   - bpo-44490(1): *note typing: 104. now searches for type parameters
     in ‘types.Union’ objects.  ‘get_type_hints’ will also properly
     resolve annotations with nested ‘types.Union’ objects.  Patch
     provided by Yurii Karabas.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44490


File: python.info,  Node: Core and Builtins<88>,  Next: Library<90>,  Prev: Library<89>,  Up: Python 3 11 0 alpha 1

1.23.43.16 Core and Builtins
............................

   - bpo-43950(1): Code objects can now provide the column information
     for instructions when available.  This is levaraged during
     traceback printing to show the expressions responsible for errors.

     Contributed by Pablo Galindo, Batuhan Taskaya and Ammar Askar as
     part of PEP 657(2).

   - bpo-44562(3): Remove uses of *note PyObject_GC_Del(): 1553. in
     error path when initializing *note types.GenericAlias: 7f0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43950

   (2) https://peps.python.org/pep-0657/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44562


File: python.info,  Node: Library<90>,  Next: Core and Builtins<89>,  Prev: Core and Builtins<88>,  Up: Python 3 11 0 alpha 1

1.23.43.17 Library
..................

   - bpo-41486(1): Fix a memory consumption and copying performance
     regression in earlier 3.10 beta releases if someone used an output
     buffer larger than 4GiB with zlib.decompress on input data that
     expands that large.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41486


File: python.info,  Node: Core and Builtins<89>,  Next: Library<91>,  Prev: Library<90>,  Up: Python 3 11 0 alpha 1

1.23.43.18 Core and Builtins
............................

   - bpo-43908(1): Heap types with the *note Py_TPFLAGS_IMMUTABLETYPE:
     3c5. flag can now inherit the PEP 590(2) vectorcall protocol.
     Previously, this was only possible for *note static types: 782.
     Patch by Erlend E. Aasland.

   - bpo-44553(3): Implement GC methods for ‘types.Union’ to break
     reference cycles and prevent memory leaks.

   - bpo-44490(4): Add ‘__parameters__’ attribute and ‘__getitem__’
     operator to ‘types.Union’.  Patch provided by Yurii Karabas.

   - bpo-44523(5): Remove the pass-through for *note hash(): 5ee. of
     *note weakref.proxy: a5f. objects to prevent unintended
     consequences when the original referred object dies while the proxy
     is part of a hashable object.  Patch by Pablo Galindo.

   - bpo-44483(6): Fix a crash in ‘types.Union’ objects when creating a
     union of an object with bad ‘__module__’ field.

   - bpo-44486(7): Modules will always have a dictionary, even when
     created by ‘types.ModuleType.__new__()’

   - bpo-44472(8): Fix ltrace functionality when exceptions are raised.
     Patch by Pablo Galindo

   - bpo-12022(9): A *note TypeError: 2c3. is now raised instead of an
     *note AttributeError: 34e. in *note with: 5d5. and *note async
     with: 5d8. statements for objects which do not support the *note
     context manager: 5d7. or *note asynchronous context manager: 5da.
     protocols correspondingly.

   - bpo-44297(10): Make sure that the line number is set when entering
     a comprehension scope.  This ensures that backtraces including
     generator expressions show the correct line number.

   - bpo-44456(11): Improve the syntax error when mixing positional and
     keyword patterns.  Patch by Pablo Galindo.

   - bpo-44409(12): Fix error location information for tokenizer errors
     raised on initialization of the tokenizer.  Patch by Pablo Galindo.

   - bpo-44396(13): Fix a possible crash in the tokenizer when raising
     syntax errors for unclosed strings.  Patch by Pablo Galindo.

   - bpo-44376(14): Exact integer exponentiation (like ‘i**2’ or ‘pow(i,
     2)’) with a small exponent is much faster, due to reducing overhead
     in such cases.

   - bpo-44313(15): Directly imported objects and modules (through
     import and from import statements) don’t generate
     ‘LOAD_METHOD’/‘CALL_METHOD’ for directly accessed objects on their
     namespace.  They now use the regular ‘LOAD_ATTR’/‘CALL_FUNCTION’.

   - bpo-44338(16): Implement adaptive specialization for LOAD_GLOBAL

     Two specialized forms of LOAD_GLOBAL are added:

        * LOAD_GLOBAL_MODULE

        * LOAD_GLOBAL_BUILTIN

   - bpo-44368(17): Improve syntax errors for invalid “as” targets.
     Patch by Pablo Galindo

   - bpo-44349(18): Fix an edge case when displaying text from files
     with encoding in syntax errors.  Patch by Pablo Galindo.

   - bpo-44337(19): Initial implementation of adaptive specialization of
     LOAD_ATTR

     Four specialized forms of LOAD_ATTR are added:

        * LOAD_ATTR_SLOT

        * LOAD_ATTR_SPLIT_KEYS

        * LOAD_ATTR_WITH_HINT

        * LOAD_ATTR_MODULE

   - bpo-44335(20): Fix a regression when identifying incorrect
     characters in syntax errors.  Patch by Pablo Galindo

   - bpo-43693(21): Computation of the offsets of cell variables is done
     in the compiler instead of at runtime.  This reduces the overhead
     of handling cell and free variables, especially in the case where a
     variable is both an argument and cell variable.

   - bpo-44317(22): Improve tokenizer error with improved locations.
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43908

   (2) https://peps.python.org/pep-0590/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44553

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44490

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44523

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44483

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44486

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44472

   (9) https://bugs.python.org/issue?@action=redirect&bpo=12022

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44297

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44456

   (12) https://bugs.python.org/issue?@action=redirect&bpo=44409

   (13) https://bugs.python.org/issue?@action=redirect&bpo=44396

   (14) https://bugs.python.org/issue?@action=redirect&bpo=44376

   (15) https://bugs.python.org/issue?@action=redirect&bpo=44313

   (16) https://bugs.python.org/issue?@action=redirect&bpo=44338

   (17) https://bugs.python.org/issue?@action=redirect&bpo=44368

   (18) https://bugs.python.org/issue?@action=redirect&bpo=44349

   (19) https://bugs.python.org/issue?@action=redirect&bpo=44337

   (20) https://bugs.python.org/issue?@action=redirect&bpo=44335

   (21) https://bugs.python.org/issue?@action=redirect&bpo=43693

   (22) https://bugs.python.org/issue?@action=redirect&bpo=44317


File: python.info,  Node: Library<91>,  Next: Core and Builtins<90>,  Prev: Core and Builtins<89>,  Up: Python 3 11 0 alpha 1

1.23.43.19 Library
..................

   - bpo-44304(1): Fix a crash in the *note sqlite3: cf. module that
     happened when the garbage collector clears ‘sqlite.Statement’
     objects.  Patch by Pablo Galindo

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44304


File: python.info,  Node: Core and Builtins<90>,  Next: Library<92>,  Prev: Library<91>,  Up: Python 3 11 0 alpha 1

1.23.43.20 Core and Builtins
............................

   - bpo-44305(1): Improve error message for ‘try’ blocks without
     ‘except’ or ‘finally’ blocks.  Patch by Pablo Galindo.

   - bpo-43413(2): Constructors of subclasses of some builtin classes
     (e.g.  *note tuple: 373, *note list: 614, *note frozenset: 5dd.) no
     longer accept arbitrary keyword arguments.  [reverted in 3.11a4]
     Subclass of *note set: 5dc. can now define a ‘__new__()’ method
     with additional keyword parameters without overriding also
     ‘__init__()’.

   - bpo-43667(3): Improve Unicode support in non-UTF locales on Oracle
     Solaris.  This issue does not affect other Solaris systems.

   - bpo-43693(4): A new opcode MAKE_CELL has been added that
     effectively moves some of the work done on function entry into the
     compiler and into the eval loop.  In addition to creating the
     required cell objects, the new opcode converts relevant arguments
     (and other locals) to cell variables on function entry.

   - bpo-44232(5): Fix a regression in *note type(): d71. when a
     metaclass raises an exception.  The C function ‘type_new()’ must
     properly report the exception when a metaclass constructor raises
     an exception and the winner class is not the metaclass.  Patch by
     Victor Stinner.

   - bpo-44201(6): Avoid side effects of checking for specialized syntax
     errors in the REPL that was causing it to ask for extra tokens
     after a syntax error had been detected.  Patch by Pablo Galindo

   - bpo-43693(7): ‘PyCodeObject’ gained ‘co_fastlocalnames’ and
     ‘co_fastlocalkinds’ as the authoritative source of fast locals
     info.  Marshaled code objects have changed accordingly.

   - bpo-44184(8): Fix a crash at Python exit when a deallocator
     function removes the last strong reference to a heap type.  Patch
     by Victor Stinner.

   - bpo-44187(9): Implement quickening in the interpreter.  This offers
     no advantages as yet, but is an enabler of future optimizations.
     See PEP 659 for full explanation.

   - bpo-44180(10): The parser doesn’t report generic syntax errors that
     happen in a position further away that the one it reached in the
     first pass.  Patch by Pablo Galindo

   - bpo-44168(11): Fix error message in the parser involving keyword
     arguments with invalid expressions.  Patch by Pablo Galindo

   - bpo-44156(12): String caches in ‘compile.c’ are now subinterpreter
     compatible.

   - bpo-44143(13): Fixed a crash in the parser that manifest when
     raising tokenizer errors when an existing exception was present.
     Patch by Pablo Galindo.

   - bpo-44032(14): Move ‘fast’ locals and other variables from the
     frame object to a per-thread datastack.

   - bpo-44114(15): Fix incorrect dictkeys_reversed and
     dictitems_reversed function signatures in C code, which broke
     webassembly builds.

   - bpo-44110(16): Improve ‘str.__getitem__()’ error message

   - bpo-26110(17): Add ‘CALL_METHOD_KW’ opcode to speed up method calls
     with keyword arguments.  Idea originated from PyPy.  A side effect
     is executing ‘CALL_METHOD’ is now branchless in the evaluation
     loop.

   - bpo-28307(18): Compiler now optimizes simple C-style formatting
     with literal format containing only format codes %s, %r and %a by
     converting them to f-string expressions.

   - bpo-43149(19): Correct the syntax error message regarding multiple
     exception types to not refer to “exception groups”.  Patch by Pablo
     Galindo

   - bpo-43822(20): The parser will prioritize tokenizer errors over
     custom syntax errors when raising exceptions.  Patch by Pablo
     Galindo.

   - bpo-40222(21): “Zero cost” exception handling.

        * Uses a lookup table to determine how to handle exceptions.

        * Removes SETUP_FINALLY and POP_TOP block instructions,
          eliminating the runtime overhead of try statements.

        * Reduces the size of the frame object by about 60%.

     Patch by Mark Shannon

   - bpo-43918(22): Document the signature and ‘default’ argument in the
     docstring of the new ‘anext’ builtin.

   - bpo-43833(23): Emit a deprecation warning if the numeric literal is
     immediately followed by one of keywords: and, else, for, if, in,
     is, or.  Raise a syntax error with more informative message if it
     is immediately followed by other keyword or identifier.

   - bpo-43879(24): Add native_thread_id to PyThreadState.  Patch by
     Gabriele N. Tornetta.

   - bpo-43693(25): Compute cell offsets relative to locals in compiler.
     Allows the interpreter to treats locals and cells a single array,
     which is slightly more efficient.  Also make the LOAD_CLOSURE
     opcode an alias for LOAD_FAST. Preserving LOAD_CLOSURE helps keep
     bytecode a bit more readable.

   - bpo-17792(26): More accurate error messages for access of unbound
     locals or free vars.

   - bpo-28146(27): Fix a confusing error message in *note str.format():
     624.

   - bpo-11105(28): When compiling *note ast.AST: 1a6. objects with
     recursive references through *note compile(): 192, the interpreter
     doesn’t crash anymore instead it raises a *note RecursionError:
     d96.

   - bpo-39091(29): Fix crash when using passing a non-exception to a
     generator’s ‘throw()’ method.  Patch by Noah Oxer

   - bpo-33346(30): Asynchronous comprehensions are now allowed inside
     comprehensions in asynchronous functions.  Outer comprehensions
     implicitly become asynchronous.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44305

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43413

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43667

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43693

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44232

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44201

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43693

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44184

   (9) https://bugs.python.org/issue?@action=redirect&bpo=44187

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44180

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44168

   (12) https://bugs.python.org/issue?@action=redirect&bpo=44156

   (13) https://bugs.python.org/issue?@action=redirect&bpo=44143

   (14) https://bugs.python.org/issue?@action=redirect&bpo=44032

   (15) https://bugs.python.org/issue?@action=redirect&bpo=44114

   (16) https://bugs.python.org/issue?@action=redirect&bpo=44110

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26110

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28307

   (19) https://bugs.python.org/issue?@action=redirect&bpo=43149

   (20) https://bugs.python.org/issue?@action=redirect&bpo=43822

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40222

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43918

   (23) https://bugs.python.org/issue?@action=redirect&bpo=43833

   (24) https://bugs.python.org/issue?@action=redirect&bpo=43879

   (25) https://bugs.python.org/issue?@action=redirect&bpo=43693

   (26) https://bugs.python.org/issue?@action=redirect&bpo=17792

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28146

   (28) https://bugs.python.org/issue?@action=redirect&bpo=11105

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39091

   (30) https://bugs.python.org/issue?@action=redirect&bpo=33346


File: python.info,  Node: Library<92>,  Next: Documentation<34>,  Prev: Core and Builtins<90>,  Up: Python 3 11 0 alpha 1

1.23.43.21 Library
..................

   - bpo-45371(1): Fix clang rpath issue in ‘distutils’.  The
     UnixCCompiler now uses correct clang option to add a runtime
     library directory (rpath) to a shared library.

   - bpo-45329(2): Fix freed memory access in ‘pyexpat.xmlparser’ when
     building it with an installed expat library <= 2.2.0.

   - bpo-41710(3): On Unix, if the ‘sem_clockwait()’ function is
     available in the C library (glibc 2.30 and newer), the *note
     threading.Lock.acquire(): 69b. method now uses the monotonic clock
     (*note time.CLOCK_MONOTONIC: 69c.) for the timeout, rather than
     using the system clock (*note time.CLOCK_REALTIME: 69d.), to not be
     affected by system clock changes.  Patch by Victor Stinner.

   - bpo-1596321(4): Fix the ‘threading._shutdown()’ function when the
     *note threading: ed. module was imported first from a thread
     different than the main thread: no longer log an error at Python
     exit.

   - bpo-45274(5): Fix a race condition in the *note Thread.join():
     1229. method of the *note threading: ed. module.  If the function
     is interrupted by a signal and the signal handler raises an
     exception, make sure that the thread remains in a consistent state
     to prevent a deadlock.  Patch by Victor Stinner.

   - bpo-21302(6): In Unix operating systems, *note time.sleep(): 6a0.
     now uses the ‘nanosleep()’ function, if ‘clock_nanosleep()’ is not
     available but ‘nanosleep()’ is available.  ‘nanosleep()’ allows to
     sleep with nanosecond precision.

   - bpo-21302(7): On Windows, *note time.sleep(): 6a0. now uses a
     waitable timer which has a resolution of 100 nanoseconds (10^-7
     seconds).  Previously, it had a resolution of 1 millisecond (10^-3
     seconds).  Patch by Benjamin Szőke and Victor Stinner.

   - bpo-45238(8): Fix ‘unittest.IsolatedAsyncioTestCase.debug()’: it
     runs now asynchronous methods and callbacks.

   - bpo-36674(9): *note unittest.TestCase.debug(): 19ef. raises now a
     *note unittest.SkipTest: 101f. if the class or the test method are
     decorated with the skipping decorator.

   - bpo-45235(10): Fix an issue where argparse would not preserve
     values in a provided namespace when using a subparser with
     defaults.

   - bpo-45183(11): Have zipimport.zipimporter.find_spec() not raise an
     exception when the underlying zip file has been deleted and the
     internal cache has been reset via invalidate_cache().

   - bpo-45234(12): Fixed a regression in *note copyfile(): a67, *note
     copy(): a68, *note copy2(): a69. raising *note FileNotFoundError:
     42e. when source is a directory, which should raise *note
     IsADirectoryError: 1097.

   - bpo-45228(13): Fix stack buffer overflow in parsing J1939 network
     address.

   - bpo-45225(14): use map function instead of genexpr in capwords.

   - bpo-42135(15): Fix typo: ‘importlib.find_loader’ is really slated
     for removal in Python 3.12 not 3.10, like the others in PR 25169.

     Patch by Hugo van Kemenade.

   - bpo-20524(16): Improves error messages on ‘.format()’ operation for
     ‘str’, ‘float’, ‘int’, and ‘complex’.  New format now shows the
     problematic pattern and the object type.

   - bpo-45168(17): Change *note dis.dis(): b4c. output to omit op arg
     values that cannot be resolved due to ‘co_consts’, ‘co_names’ etc
     not being provided.  Previously the oparg itself was repeated in
     the value field, which is not useful and can be confusing.

   - bpo-21302(18): In Unix operating systems, *note time.sleep(): 6a0.
     now uses the ‘clock_nanosleep()’ function, if available, which
     allows to sleep for an interval specified with nanosecond
     precision.

   - bpo-45173(19): Remove from the *note configparser: 22. module: the
     ‘SafeConfigParser’ class, the ‘filename’ property of the *note
     ParsingError: 508. class, the ‘readfp()’ method of the *note
     ConfigParser: 1c8. class, deprecated since Python 3.2.

     Patch by Hugo van Kemenade.

   - bpo-44987(20): Pure ASCII strings are now normalized in constant
     time by *note unicodedata.normalize(): 6d8.  Patch by Donghee Na.

   - bpo-35474(21): Calling *note mimetypes.guess_all_extensions():
     19f0. with ‘strict=False’ no longer affects the result of the
     following call with ‘strict=True’.  Also, mutating the returned
     list no longer affects the global state.

   - bpo-45166(22): *note typing.get_type_hints(): 6b4. now works with
     *note Final: 267. wrapped in *note ForwardRef: 197f.

   - bpo-45162(23): Remove many old deprecated *note unittest: 106.
     features:

        * “‘fail*’” and “‘assert*’” aliases of *note TestCase: 451.
          methods.

        * Broken from start *note TestCase: 451. method
          ‘assertDictContainsSubset()’.

        * Ignored ‘<unittest.TestLoader.loadTestsFromModule>
          TestLoader.loadTestsFromModule()’ parameter 'use_load_tests'.

        * Old alias ‘_TextTestResult’ of *note TextTestResult: 534.

   - bpo-38371(24): Remove the deprecated ‘split()’ method of
     ‘_tkinter.TkappType’.  Patch by Erlend E. Aasland.

   - bpo-20499(25): Improve the speed and accuracy of
     statistics.pvariance().

   - bpo-45132(26): Remove *note __getitem__(): 283. methods of *note
     xml.dom.pulldom.DOMEventStream: 738, *note
     wsgiref.util.FileWrapper: 739. and *note fileinput.FileInput: 73a,
     deprecated since Python 3.9.

     Patch by Hugo van Kemenade.

   - bpo-45129(27): Due to significant security concerns, the
     'reuse_address' parameter of *note
     asyncio.loop.create_datagram_endpoint(): 736, disabled in Python
     3.9, is now entirely removed.  This is because of the behavior of
     the socket option ‘SO_REUSEADDR’ in UDP.

     Patch by Hugo van Kemenade.

   - bpo-45124(28): The ‘bdist_msi’ command, deprecated in Python 3.9,
     is now removed.

     Use ‘bdist_wheel’ (wheel packages) instead.

     Patch by Hugo van Kemenade.

   - bpo-30856(29): *note unittest.TestResult: 11ab. methods *note
     addFailure(): 19f1, *note addError(): 19f2, *note addSkip(): 19f3.
     and *note addSubTest(): 19f4. are now called immediately after
     raising an exception in test or finishing a subtest.  Previously
     they were called only after finishing the test clean up.

   - bpo-45034(30): Changes how error is formatted for ‘struct.pack’
     with ‘'H'’ and ‘'h'’ modes and too large / small numbers.  Now it
     shows the actual numeric limits, while previously it was showing
     arithmetic expressions.

   - bpo-25894(31): *note unittest: 106. now always reports skipped and
     failed subtests separately: separate characters in default mode and
     separate lines in verbose mode.  Also the test description is now
     output for errors in test method, class and module cleanups.

   - bpo-45081(32): Fix issue when dataclasses that inherit from
     ‘typing.Protocol’ subclasses have wrong ‘__init__’.  Patch provided
     by Yurii Karabas.

   - bpo-45085(33): The ‘binhex’ module, deprecated in Python 3.9, is
     now removed.  The following *note binascii: 10. functions,
     deprecated in Python 3.9, are now also removed:

        * ‘a2b_hqx()’, ‘b2a_hqx()’;

        * ‘rlecode_hqx()’, ‘rledecode_hqx()’.

     The *note binascii.crc_hqx(): 737. function remains available.

     Patch by Victor Stinner.

   - bpo-40360(34): The ‘lib2to3’ package is now deprecated and may not
     be able to parse Python 3.10 or newer.  See the PEP 617(35) (New
     PEG parser for CPython).  Patch by Victor Stinner.

   - bpo-45075(36): Rename ‘traceback.StackSummary.format_frame()’ to
     *note traceback.StackSummary.format_frame_summary(): 6a6.  This
     method was added for 3.11 so it was not released yet.

     Updated code and docs to better distinguish frame and FrameSummary.

   - bpo-31299(37): Add option to completely drop frames from a
     traceback by returning ‘None’ from a ‘format_frame()’ override.

   - bpo-41620(38): *note run(): 11aa. now always return a *note
     TestResult: 11ab. instance.  Previously it returned ‘None’ if the
     test class or method was decorated with a skipping decorator.

   - bpo-45021(39): Fix a potential deadlock at shutdown of forked
     children when using *note concurrent.futures: 21. module

   - bpo-43913(40): Fix bugs in cleaning up classes and modules in *note
     unittest: 106.:

        * Functions registered with *note addModuleCleanup(): a59. were
          not called unless the user defines ‘tearDownModule()’ in their
          test module.

        * Functions registered with *note addClassCleanup(): a5a. were
          not called if ‘tearDownClass’ is set to ‘None’.

        * Buffering in *note TestResult: 11ab. did not work with
          functions registered with ‘addClassCleanup()’ and
          ‘addModuleCleanup()’.

        * Errors in functions registered with ‘addClassCleanup()’ and
          ‘addModuleCleanup()’ were not handled correctly in buffered
          and debug modes.

        * Errors in ‘setUpModule()’ and functions registered with
          ‘addModuleCleanup()’ were reported in wrong order.

        * And several lesser bugs.

   - bpo-45030(41): Fix integer overflow in pickling and copying the
     range iterator.

   - bpo-45001(42): Made email date parsing more robust against
     malformed input, namely a whitespace-only ‘Date:’ header.  Patch by
     Wouter Bolsterlee.

   - bpo-45010(43): Remove support of special method ‘__div__’ in *note
     unittest.mock: 107.  It is not used in Python 3.

   - bpo-39218(44): Improve accuracy of variance calculations by using
     ‘x*x’ instead of ‘x**2’.

   - bpo-43613(45): Improve the speed of *note gzip.compress(): 641. and
     *note gzip.decompress(): 1252. by compressing and decompressing at
     once in memory instead of in a streamed fashion.

   - bpo-37596(46): Ensure that *note set: 5dc. and *note frozenset:
     5dd. objects are always *note marshalled: 8d. reproducibly.

   - bpo-44019(47): A new function ‘operator.call’ has been added, such
     that ‘operator.call(obj, *args, **kwargs) == obj(*args, **kwargs)’.

   - bpo-42255(48): ‘webbrowser.MacOSX’ is deprecated and will be
     removed in Python 3.13.  It is untested and undocumented and also
     not used by *note webbrowser: 115. itself.  Patch by Donghee Na.

   - bpo-44955(49): Method *note stopTestRun(): 1396. is now always
     called in pair with method *note startTestRun(): 1395. for *note
     TestResult: 11ab. objects implicitly created in *note run(): 11aa.
     Previously it was not called for test methods and classes decorated
     with a skipping decorator.

   - bpo-39039(50): tarfile.open raises *note ReadError: 19f5. when a
     zlib error occurs during file extraction.

   - bpo-44935(51): *note subprocess: d6. on Solaris now also uses *note
     os.posix_spawn(): 220. for better performance.

   - bpo-44911(52): *note IsolatedAsyncioTestCase: 30c. will no longer
     throw an exception while cancelling leaked tasks.  Patch by Bar
     Harel.

   - bpo-41322(53): Added ‘DeprecationWarning’ for tests and async tests
     that return a value!=None (as this may indicate an improperly
     written test, for example a test written as a generator function).

   - bpo-44524(54): Make exception message more useful when subclass
     from typing special form alias.  Patch provided by Yurii Karabas.

   - bpo-38956(55): *note argparse.BooleanOptionalAction: 1996.’s
     default value is no longer printed twice when used with *note
     argparse.ArgumentDefaultsHelpFormatter: 19f6.

   - bpo-44860(56): Fix the ‘posix_user’ scheme in *note sysconfig: db.
     to not depend on *note sys.platlibdir: 942.

   - bpo-44859(57): Improve error handling in *note sqlite3: cf. and
     raise more accurate exceptions.

        * *note MemoryError: 15ab. is now raised instead of *note
          sqlite3.Warning: 195b. when memory is not enough for encoding
          a statement to UTF-8 in ‘Connection.__call__()’ and
          ‘Cursor.execute()’.

        * ‘UnicodEncodeError’ is now raised instead of *note
          sqlite3.Warning: 195b. when the statement contains surrogate
          characters in ‘Connection.__call__()’ and ‘Cursor.execute()’.

        * *note TypeError: 2c3. is now raised instead of *note
          ValueError: 202. for non-string script argument in
          ‘Cursor.executescript()’.

        * *note ValueError: 202. is now raised for script containing the
          null character instead of truncating it in
          ‘Cursor.executescript()’.

        * Correctly handle exceptions raised when getting boolean value
          of the result of the progress handler.

        * Add many tests covering different corner cases.

   - bpo-44581(58): Upgrade bundled pip to 21.2.3 and setuptools to
     57.4.0

   - bpo-44849(59): Fix the *note os.set_inheritable(): f32. function on
     FreeBSD 14 for file descriptor opened with the *note O_PATH: fab.
     flag: ignore the *note EBADF: 965. error on ‘ioctl()’, fallback on
     the ‘fcntl()’ implementation.  Patch by Victor Stinner.

   - bpo-44605(60): The @functools.total_ordering() decorator now works
     with metaclasses.

   - bpo-44524(61): Fixed an issue wherein the ‘__name__’ and
     ‘__qualname__’ attributes of subscribed specialforms could be
     ‘None’.

   - bpo-44839(62): *note MemoryError: 15ab. raised in user-defined
     functions will now produce a ‘MemoryError’ in *note sqlite3: cf.
     *note OverflowError: 888. will now be converted to *note DataError:
     19f7.  Previously *note OperationalError: 19f8. was produced in
     these cases.

   - bpo-44822(63): *note sqlite3: cf. user-defined functions and
     aggregators returning *note strings: 44f. with embedded NUL
     characters are no longer truncated.  Patch by Erlend E. Aasland.

   - bpo-44801(64): Ensure that the *note ParamSpec: 15e. variable in
     Callable can only be substituted with a parameters expression (a
     list of types, an ellipsis, ParamSpec or Concatenate).

   - bpo-44806(65): Non-protocol subclasses of *note typing.Protocol:
     264. ignore now the ‘__init__’ method inherited from protocol base
     classes.

   - bpo-27275(66): *note collections.OrderedDict.popitem(): 1336. and
     ‘collections.OrderedDict.pop()’ no longer call ‘__getitem__’ and
     ‘__delitem__’ methods of the OrderedDict subclasses.

   - bpo-44793(67): Fix checking the number of arguments when subscribe
     a generic type with ‘ParamSpec’ parameter.

   - bpo-44784(68): In importlib.metadata tests, override warnings
     behavior under expected DeprecationWarnings (importlib_metadata
     4.6.3).

   - bpo-44667(69): The *note tokenize.tokenize(): 4dc. doesn’t
     incorrectly generate a ‘NEWLINE’ token if the source doesn’t end
     with a new line character but the last line is a comment, as the
     function is already generating a ‘NL’ token.  Patch by Pablo
     Galindo

   - bpo-44771(70): Added ‘importlib.simple’ module implementing
     adapters from a low-level resources reader interface to a
     ‘TraversableResources’ interface.  Legacy API (‘path’, ‘contents’,
     …) is now supported entirely by the ‘.files()’ API with a
     compatibility shim supplied for resource loaders without that
     functionality.  Feature parity with ‘importlib_resources’ 5.2.

   - bpo-44752(71): ‘rcompleter’ does not call *note getattr(): bf0. on
     *note property: 194. objects to avoid the side-effect of evaluating
     the corresponding method.

   - bpo-44747(72): Refactor usage of ‘sys._getframe’ in ‘typing’
     module.  Patch provided by Yurii Karabas.

   - bpo-42378(73): Fixes the issue with log file being overwritten when
     *note logging.FileHandler: 19f9. is used in *note atexit: c. with
     'filemode' set to ‘'w'’.  Note this will cause the message in
     'atexit' not being logged if the log stream is already closed due
     to shutdown of logging.

   - bpo-44720(74): ‘weakref.proxy’ objects referencing non-iterators
     now raise ‘TypeError’ rather than dereferencing the null
     ‘tp_iternext’ slot and crashing.

   - bpo-44704(75): The implementation of ‘collections.abc.Set._hash()’
     now matches that of ‘frozenset.__hash__()’.

   - bpo-44666(76): Fixed issue in *note compileall.compile_file(): e11.
     when ‘sys.stdout’ is redirected.  Patch by Stefan Hölzl.

   - bpo-44688(77): *note sqlite3.Connection.create_collation(): 679.
     now accepts non-ASCII collation names.  Patch by Erlend E. Aasland.

   - bpo-44690(78): Adopt 'binacii.a2b_base64'’s strict mode in
     'base64.b64decode'.

   - bpo-42854(79): Fixed a bug in the ‘_ssl’ module that was throwing
     *note OverflowError: 888. when using ‘_ssl._SSLSocket.write()’ and
     ‘_ssl._SSLSocket.read()’ for a big value of the ‘len’ parameter.
     Patch by Pablo Galindo.

   - bpo-44686(80): Replace ‘unittest.mock._importer’ with
     ‘pkgutil.resolve_name’.

   - bpo-44353(81): Make ‘NewType.__call__’ faster by implementing it in
     C. Patch provided by Yurii Karabas.

   - bpo-44682(82): Change the *note pdb: a5. 'commands' directive to
     disallow setting commands for an invalid breakpoint and to display
     an appropriate error.

   - bpo-44353(83): Refactor ‘typing.NewType’ from function into
     callable class.  Patch provided by Yurii Karabas.

   - bpo-44678(84): Added a separate error message for discontinuous
     padding in 'binascii.a2b_base64' strict mode.

   - bpo-44524(85): Add missing ‘__name__’ and ‘__qualname__’ attributes
     to ‘typing’ module classes.  Patch provided by Yurii Karabas.

   - bpo-40897(86): Give priority to using the current class constructor
     in *note inspect.signature(): 73b.  Patch by Weipeng Hong.

   - bpo-44638(87): Add a reference to the zipp project and hint as to
     how to use it.

   - bpo-44648(88): Fixed wrong error being thrown by *note
     inspect.getsource(): 1619. when examining a class in the
     interactive session.  Instead of *note TypeError: 2c3, it should be
     *note OSError: 41a. with appropriate error message.

   - bpo-44608(89): Fix memory leak in ‘_tkinter._flatten()’ if it is
     called with a sequence or set, but not list or tuple.

   - bpo-44594(90): Fix an edge case of ‘ExitStack’ and ‘AsyncExitStack’
     exception chaining.  They will now match ‘with’ block behavior when
     ‘__context__’ is explicitly set to ‘None’ when the exception is in
     flight.

   - bpo-42799(91): In *note fnmatch: 5c, the cache size for compiled
     regex patterns (*note functools.lru_cache(): 9fa.) was bumped up
     from 256 to 32768, affecting functions: *note fnmatch.fnmatch():
     19fa, *note fnmatch.fnmatchcase(): 19fb, *note fnmatch.filter():
     19fc.

   - bpo-41928(92): Update *note shutil.copyfile(): a67. to raise *note
     FileNotFoundError: 42e. instead of confusing *note
     IsADirectoryError: 1097. when a path ending with a ‘os.path.sep’
     does not exist; *note shutil.copy(): a68. and *note shutil.copy2():
     a69. are also affected.

   - bpo-44569(93): Added the ‘StackSummary.format_frame()’ function in
     *note traceback: fe.  This allows users to customize the way
     individual lines are formatted in tracebacks without
     re-implementing logic to handle recursive tracebacks.

   - bpo-44566(94): handle StopIteration subclass raised from
     @contextlib.contextmanager generator

   - bpo-44558(95): Make the implementation consistency of *note
     indexOf(): 8e4. between C and Python versions.  Patch by Donghee
     Na.

   - bpo-41249(96): Fixes ‘TypedDict’ to work with
     ‘typing.get_type_hints()’ and postponed evaluation of annotations
     across modules.

   - bpo-44554(97): Refactor argument processing in ‘pdb.main()’ to
     simplify detection of errors in input loading and clarify behavior
     around module or script invocation.

   - bpo-34798(98): Break up paragraph about *note pprint.PrettyPrinter:
     fb8. construction parameters to make it easier to read.

   - bpo-44539(99): Added support for recognizing JPEG files without
     JFIF or Exif markers.

   - bpo-44461(100): Fix bug with *note pdb: a5.’s handling of import
     error due to a package which does not have a ‘__main__’ module

   - bpo-43625(101): Fix a bug in the detection of CSV file headers by
     *note csv.Sniffer.has_header(): 19fd. and improve documentation of
     same.

   - bpo-44516(102): Update vendored pip to 21.1.3

   - bpo-42892(103): Fixed an exception thrown while parsing a malformed
     multipart email by *note email.message.EmailMessage: 27b.

   - bpo-44468(104): *note typing.get_type_hints(): 6b4. now finds
     annotations in classes and base classes with unexpected
     ‘__module__’.  Previously, it skipped those MRO elements.

   - bpo-44491(105): Allow clearing the *note sqlite3: cf. authorizer
     callback by passing *note None: 678. to *note set_authorizer():
     2ab.  Patch by Erlend E. Aasland.

   - bpo-43977(106): Set the proper *note Py_TPFLAGS_MAPPING: 19fe. and
     *note Py_TPFLAGS_SEQUENCE: 19ff. flags for subclasses created
     before a parent has been registered as a *note
     collections.abc.Mapping: 8d3. or *note collections.abc.Sequence:
     1209.

   - bpo-44482(107): Fix very unlikely resource leak in *note glob: 64.
     in alternate Python implementations.

   - bpo-44466(108): The *note faulthandler: 58. module now detects if a
     fatal error occurs during a garbage collector collection.  Patch by
     Victor Stinner.

   - bpo-44471(109): A *note TypeError: 2c3. is now raised instead of an
     *note AttributeError: 34e. in *note
     contextlib.ExitStack.enter_context(): 5d6. and *note
     contextlib.AsyncExitStack.enter_async_context(): 5d9. for objects
     which do not support the *note context manager: 5d7. or *note
     asynchronous context manager: 5da. protocols correspondingly.

   - bpo-44404(110): *note tkinter: f0.’s ‘after()’ method now supports
     callables without the ‘__name__’ attribute.

   - bpo-41546(111): Make *note pprint: ae. (like the builtin ‘print’)
     not attempt to write to ‘stdout’ when it is ‘None’.

   - bpo-44458(112): ‘BUFFER_BLOCK_SIZE’ is now declared static, to
     avoid linking collisions when bz2, lmza or zlib are statically
     linked.

   - bpo-44464(113): Remove exception for flake8 in deprecated
     importlib.metadata interfaces.  Sync with importlib_metadata 4.6.

   - bpo-44446(114): Take into account that ‘lineno’ might be ‘None’ in
     *note traceback.FrameSummary: eb8.

   - bpo-44439(115): Fix in ‘bz2.BZ2File.write()’ /
     ‘lzma.LZMAFile.write()’ methods, when the input data is an object
     that supports the buffer protocol, the file length may be wrong.

   - bpo-44434(116): _thread.start_new_thread() no longer calls
     PyThread_exit_thread() explicitly at the thread exit, the call was
     redundant.  On Linux with the glibc, pthread_exit() aborts the
     whole process if dlopen() fails to open libgcc_s.so file (ex:
     EMFILE error).  Patch by Victor Stinner.

   - bpo-42972(117): The _thread.RLock type now fully implement the GC
     protocol: add a traverse function and the *note Py_TPFLAGS_HAVE_GC:
     780. flag.  Patch by Victor Stinner.

   - bpo-44422(118): The *note threading.enumerate(): 1a00. function now
     uses a reentrant lock to prevent a hang on reentrant call.  Patch
     by Victor Stinner.

   - bpo-38291(119): Importing typing.io or typing.re now prints a
     ‘DeprecationWarning’.

   - bpo-37880(120): argparse actions store_const and append_const each
     receive a default value of ‘None’ when the ‘const’ kwarg is not
     provided.  Previously, this raised a *note TypeError: 2c3.

   - bpo-44389(121): Fix deprecation of *note ssl.OP_NO_TLSv1_3: 1a01.

   - bpo-27827(122): ‘pathlib.PureWindowsPath.is_reserved()’ now
     identifies a greater range of reserved filenames, including those
     with trailing spaces or colons.

   - bpo-44395(123): Fix ‘as_string()’ to pass unixfrom properly.  Patch
     by Donghee Na.

   - bpo-34266(124): Handle exceptions from parsing the arg of *note
     pdb: a5.’s run/restart command.

   - bpo-44362(125): Improve *note ssl: d0. module’s deprecation
     messages, error reporting, and documentation for deprecations.

   - bpo-44342(126): [Enum] Change pickling from by-value to by-name.

   - bpo-44356(127): [Enum] Allow multiple data-type mixins if they are
     all the same.

   - bpo-44351(128): Restore back ‘parse_makefile()’ in
     ‘distutils.sysconfig’ because it behaves differently than the
     similar implementation in *note sysconfig: db.

   - bpo-35800(129): ‘smtpd.MailmanProxy’ is now removed as it is
     unusable without an external module, ‘mailman’.  Patch by Donghee
     Na.

   - bpo-44357(130): Added a function that returns cube root of the
     given number *note math.cbrt(): 664.

   - bpo-44339(131): Change ‘math.pow(±0.0, -math.inf)’ to return ‘inf’
     instead of raising ‘ValueError’.  This brings the special-case
     handling of ‘math.pow’ into compliance with the IEEE 754 standard.

   - bpo-44242(132): Remove missing flag check from Enum creation and
     move into a ‘verify’ decorator.

   - bpo-44246(133): In ‘importlib.metadata’, restore compatibility in
     the result from ‘Distribution.entry_points’ (‘EntryPoints’) to
     honor expectations in older implementations and issuing deprecation
     warnings for these cases: A. ‘EntryPoints’ objects are once again
     mutable, allowing for ‘sort()’ and other list-based mutation
     operations.  Avoid deprecation warnings by casting to a mutable
     sequence (e.g.  ‘list(dist.entry_points).sort()’).  B.
     ‘EntryPoints’ results once again allow for access by index.  To
     avoid deprecation warnings, cast the result to a Sequence first
     (e.g.  ‘tuple(dist.entry_points)[0]’).

   - bpo-44246(134): In importlib.metadata.entry_points, de-duplication
     of distributions no longer requires loading the full metadata for
     PathDistribution objects, improving entry point loading performance
     by ~10x.

   - bpo-43858(135): Added a function that returns a copy of a dict of
     logging levels: *note logging.getLevelNamesMapping(): 65c.

   - bpo-44260(136): The *note random.Random: 1a02. constructor no
     longer reads system entropy without need.

   - bpo-44254(137): On Mac, give turtledemo button text a color that
     works on both light or dark background.  Programmers cannot control
     the latter.

   - bpo-44258(138): Support PEP 515 for Fraction’s initialization from
     string.

   - bpo-44235(139): Remove deprecated functions in the *note gettext:
     63.  Patch by Donghee Na.

   - bpo-38693(140): Prefer f-strings to ‘.format’ in
     importlib.resources.

   - bpo-33693(141): Importlib.metadata now prefers f-strings to
     .format.

   - bpo-44241(142): Incorporate minor tweaks from importlib_metadata
     4.1: SimplePath protocol, support for Metadata 2.2.

   - bpo-43216(143): Remove the ‘@asyncio.coroutine’ *note decorator:
     734. enabling legacy generator-based coroutines to be compatible
     with async/await code; remove ‘asyncio.coroutines.CoroWrapper’ used
     for wrapping legacy coroutine objects in the debug mode.  The
     decorator has been deprecated since Python 3.8 and the removal was
     initially scheduled for Python 3.10.  Patch by Illia Volochii.

   - bpo-44210(144): Make importlib.metadata._meta.PackageMetadata
     public.

   - bpo-43643(145): Declare readers.MultiplexedPath.name as a property
     per the spec.

   - bpo-27334(146): The *note sqlite3: cf. context manager now performs
     a rollback (thus releasing the database lock) if commit failed.
     Patch by Luca Citi and Erlend E. Aasland.

   - bpo-4928(147): Documented existing behavior on POSIX:
     NamedTemporaryFiles are not deleted when creating process is killed
     with SIGKILL

   - bpo-44154(148): Optimize *note fractions.Fraction: 1e7. pickling
     for large components.

   - bpo-33433(149): For IPv4 mapped IPv6 addresses ( RFC 4291(150)
     Section 2.5.5.2), the *note ipaddress.IPv6Address.is_private: 1758.
     check is deferred to the mapped IPv4 address.  This solves a bug
     where public mapped IPv4 addresses were considered private by the
     IPv6 check.

   - bpo-44150(151): Add optional 'weights' argument to
     statistics.fmean().

   - bpo-44142(152): *note ast.unparse(): 8ee. will now drop the
     redundant parentheses when tuples used as assignment targets (e.g
     in for loops).

   - bpo-44145(153): *note hmac: 6a. computations were not releasing the
     GIL while calling the OpenSSL ‘HMAC_Update’ C API (a new feature in
     3.9).  This unintentionally prevented parallel computation as other
     *note hashlib: 68. algorithms support.

   - bpo-44095(154): *note zipfile.Path: 6cc. now supports *note
     zipfile.Path.stem: 6c9, *note zipfile.Path.suffixes: 6cb, and *note
     zipfile.Path.suffix: 6ca. attributes.

   - bpo-44077(155): It’s now possible to receive the type of service
     (ToS), a.k.a.  differentiated services (DS), a.k.a.  differentiated
     services code point (DSCP) and explicit congestion notification
     (ECN) IP header fields with ‘socket.IP_RECVTOS’.

   - bpo-37788(156): Fix a reference leak when a Thread object is never
     joined.

   - bpo-38908(157): Subclasses of ‘typing.Protocol’ which only have
     data variables declared will now raise a ‘TypeError’ when checked
     with ‘isinstance’ unless they are decorated with
     ‘runtime_checkable()’.  Previously, these checks passed silently.
     Patch provided by Yurii Karabas.

   - bpo-44098(158): ‘typing.ParamSpec’ will no longer be found in the
     ‘__parameters__’ of most *note typing: 104. generics except in
     valid use locations specified by PEP 612(159).  This prevents
     incorrect usage like ‘typing.List[P][int]’.  This change means
     incorrect usage which may have passed silently in 3.10 beta 1 and
     earlier will now error.

   - bpo-44089(160): Allow subclassing ‘csv.Error’ in 3.10 (it was
     allowed in 3.9 and earlier but was disallowed in early versions of
     3.10).

   - bpo-44081(161): *note ast.unparse(): 8ee. now doesn’t use redundant
     spaces to separate ‘lambda’ and the ‘:’ if there are no parameters.

   - bpo-44061(162): Fix regression in previous release when calling
     *note pkgutil.iter_modules(): d74. with a list of *note
     pathlib.Path: 229. objects

   - bpo-44059(163): Register the SerenityOS Browser in the *note
     webbrowser: 115. module.

   - bpo-36515(164): The *note hashlib: 68. module no longer does
     unaligned memory accesses when compiled for ARM platforms.

   - bpo-40465(165): Remove random module features deprecated in Python
     3.9.

   - bpo-44018(166): random.seed() no longer mutates bytearray inputs.

   - bpo-38352(167): Add ‘IO’, ‘BinaryIO’, ‘TextIO’, ‘Match’, and
     ‘Pattern’ to ‘typing.__all__’.  Patch by Jelle Zijlstra.

   - bpo-44002(168): *note urllib.parse: 10a. now uses
     ‘functool.lru_cache()’ for its internal URL splitting and quoting
     caches instead of rolling its own like its the ’90s.

     The undocumented internal *note urllib.parse: 10a. ‘Quoted’ class
     API is now deprecated, for removal in 3.14.

   - bpo-43972(169): When *note http.server.SimpleHTTPRequestHandler:
     b5c. sends a ‘301 (Moved Permanently)’ for a directory path not
     ending with ‘/’, add a ‘Content-Length: 0’ header.  This improves
     the behavior for certain clients.

   - bpo-28528(170): Fix a bug in *note pdb: a5. where ‘checkline()’
     raises *note AttributeError: 34e. if it is called after ‘reset()’.

   - bpo-43853(171): Improved string handling for *note sqlite3: cf.
     user-defined functions and aggregates:

        * It is now possible to pass strings with embedded null
          characters to UDFs

        * Conversion failures now correctly raise *note MemoryError:
          15ab.

     Patch by Erlend E. Aasland.

   - bpo-43666(172): AIX: ‘Lib/_aix_support.get_platform()’ may fail in
     an AIX WPAR. The fileset bos.rte appears to have a builddate in
     both LPAR and WPAR so this fileset is queried rather than bos.mp64.
     To prevent a similar situation (no builddate in ODM) a value (9988)
     sufficient for completing a build is provided.  Patch by M Felt.

   - bpo-43650(173): Fix *note MemoryError: 15ab. in *note
     shutil.unpack_archive(): 46e. which fails inside
     ‘shutil._unpack_zipfile()’ on large files.  Patch by Igor
     Bolshakov.

   - bpo-43612(174): *note zlib.compress(): 642. now accepts a wbits
     parameter which allows users to compress data as a raw deflate
     block without zlib headers and trailers in one go.  Previously this
     required instantiating a ‘zlib.compressobj’.  It also provides a
     faster alternative to ‘gzip.compress’ when wbits=31 is used.

   - bpo-43392(175): ‘importlib._bootstrap._find_and_load()’ now
     implements a two-step check to avoid locking when modules have been
     already imported and are ready.  This improves performance of
     repeated calls to *note importlib.import_module(): 51b. and *note
     importlib.__import__(): 10ab.

   - bpo-43318(176): Fix a bug where *note pdb: a5. does not always echo
     cleared breakpoints.

   - bpo-43234(177): Prohibit passing non-*note
     concurrent.futures.ThreadPoolExecutor: 745. executors to
     ‘loop.set_default_executor()’ following a deprecation in Python
     3.8.  Patch by Illia Volochii.

   - bpo-43232(178): Prohibit previously deprecated potentially
     disruptive operations on ‘asyncio.trsock.TransportSocket’.  Patch
     by Illia Volochii.

   - bpo-30077(179): Added support for Apple’s aifc/sowt
     pseudo-compression

   - bpo-42971(180): Add definition of ‘errno.EQFULL’ for platforms that
     define this constant (such as macOS).

   - bpo-43086(181): Added a new optional ‘strict_mode’ parameter to
     'binascii.a2b_base64'.  When ‘scrict_mode’ is set to ‘True’, the
     'a2b_base64' function will accept only valid base64 content.  More
     details about what “valid base64 content” is, can be found in the
     function’s documentation.

   - bpo-43024(182): Improve the help signature of *note
     traceback.print_exception(): 855, *note
     traceback.format_exception(): 853. and *note
     traceback.format_exception_only(): 854.

   - bpo-33809(183): Add the *note traceback.TracebackException.print():
     6a7. method which prints the formatted exception information.

   - bpo-42862(184): *note sqlite3: cf. now utilizes *note
     functools.lru_cache(): 9fa. to implement the connection statement
     cache.  As a small optimisation, the default statement cache size
     has been increased from 100 to 128.  Patch by Erlend E. Aasland.

   - bpo-41818(185): Soumendra Ganguly: add termios.tcgetwinsize(),
     termios.tcsetwinsize().

   - bpo-40497(186): *note subprocess.check_output(): ffb. now raises
     *note ValueError: 202. when the invalid keyword argument 'check' is
     passed by user code.  Previously such use would fail later with a
     *note TypeError: 2c3.  Patch by Rémi Lapeyre.

   - bpo-37449(187): ‘ensurepip’ now uses ‘importlib.resources.files()’
     traversable APIs

   - bpo-40956(188): Use Argument Clinic in *note sqlite3: cf.  Patches
     by Erlend E. Aasland.

   - bpo-41730(189): ‘DeprecationWarning’ is now raised when importing
     ‘tkinter.tix’, which has been deprecated in documentation since
     Python 3.6.

   - bpo-20684(190): Remove unused ‘_signature_get_bound_param’ function
     from *note inspect: 7e. - by Anthony Sottile.

   - bpo-41402(191): Fix *note email.message.EmailMessage.set_content():
     1a03. when called with binary data and ‘7bit’ content transfer
     encoding.

   - bpo-32695(192): The 'compresslevel' and 'preset' keyword arguments
     of *note tarfile.open(): eab. are now both documented and tested.

   - bpo-41137(193): Use utf-8 encoding while reading .pdbrc files.
     Patch by Srinivas Reddy Thatiparthy

   - bpo-24391(194): Improved reprs of *note threading: ed.
     synchronization objects: *note Semaphore: 119a, *note
     BoundedSemaphore: 119b, *note Event: 119c. and *note Barrier: 1228.

   - bpo-5846(195): Deprecated the following *note unittest: 106.
     functions, scheduled for removal in Python 3.13:

        * ‘findTestCases()’

        * ‘makeSuite()’

        * ‘getTestCaseNames()’

     Use *note TestLoader: 28e. methods instead:

        * *note unittest.TestLoader.loadTestsFromModule(): 28f.

        * *note unittest.TestLoader.loadTestsFromTestCase(): 290.

        * *note unittest.TestLoader.getTestCaseNames(): 291.

     Patch by Erlend E. Aasland.

   - bpo-40563(196): Support pathlike objects on dbm/shelve.  Patch by
     Hakan Çelik and Henry-Joseph Audéoud.

   - bpo-34990(197): Fixed a Y2k38 bug in the compileall module where it
     would fail to compile files with a modification time after the year
     2038.

   - bpo-39549(198): Whereas the code for reprlib.Repr had previously
     used a hardcoded string value of ‘…’, this PR updates it to use of
     a “fillvalue” attribute, whose value defaults to ‘…’ and can be
     reset in either individual reprlib.Repr instances or in subclasses
     thereof.

   - bpo-37022(199): *note pdb: a5. now displays exceptions from
     ‘repr()’ with its ‘p’ and ‘pp’ commands.

   - bpo-38840(200): Fix ‘test___all__’ on platforms lacking a shared
     memory implementation.

   - bpo-39359(201): Add one missing check that the password is a bytes
     object for an encrypted zipfile.

   - bpo-38741(202): *note configparser: 22.: using ‘]’ inside a section
     header will no longer cut the section name short at the ‘]’

   - bpo-38415(203): Added missing behavior to *note
     contextlib.asynccontextmanager(): b42. to match *note
     contextlib.contextmanager(): 1247. so decorated functions can
     themselves be decorators.

   - bpo-30256(204): Pass multiprocessing BaseProxy argument
     ‘manager_owned’ through AutoProxy.

   - bpo-27513(205): *note email.utils.getaddresses(): 1e1. now accepts
     *note email.header.Header: 1a04. objects along with string values.
     Patch by Zackery Spytz.

   - bpo-16379(206): Add SQLite error code and name to *note sqlite3:
     cf. exceptions.  Patch by Aviv Palivoda, Daniel Shahaf, and Erlend
     E. Aasland.

   - bpo-26228(207): pty.spawn no longer hangs on FreeBSD, macOS, and
     Solaris.

   - bpo-33349(208): lib2to3 now recognizes async generators everywhere.

   - bpo-29298(209): Fix ‘TypeError’ when required subparsers without
     ‘dest’ do not receive arguments.  Patch by Anthony Sottile.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45371

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45329

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41710

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1596321

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45274

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21302

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21302

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45238

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36674

   (10) https://bugs.python.org/issue?@action=redirect&bpo=45235

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45183

   (12) https://bugs.python.org/issue?@action=redirect&bpo=45234

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45228

   (14) https://bugs.python.org/issue?@action=redirect&bpo=45225

   (15) https://bugs.python.org/issue?@action=redirect&bpo=42135

   (16) https://bugs.python.org/issue?@action=redirect&bpo=20524

   (17) https://bugs.python.org/issue?@action=redirect&bpo=45168

   (18) https://bugs.python.org/issue?@action=redirect&bpo=21302

   (19) https://bugs.python.org/issue?@action=redirect&bpo=45173

   (20) https://bugs.python.org/issue?@action=redirect&bpo=44987

   (21) https://bugs.python.org/issue?@action=redirect&bpo=35474

   (22) https://bugs.python.org/issue?@action=redirect&bpo=45166

   (23) https://bugs.python.org/issue?@action=redirect&bpo=45162

   (24) https://bugs.python.org/issue?@action=redirect&bpo=38371

   (25) https://bugs.python.org/issue?@action=redirect&bpo=20499

   (26) https://bugs.python.org/issue?@action=redirect&bpo=45132

   (27) https://bugs.python.org/issue?@action=redirect&bpo=45129

   (28) https://bugs.python.org/issue?@action=redirect&bpo=45124

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30856

   (30) https://bugs.python.org/issue?@action=redirect&bpo=45034

   (31) https://bugs.python.org/issue?@action=redirect&bpo=25894

   (32) https://bugs.python.org/issue?@action=redirect&bpo=45081

   (33) https://bugs.python.org/issue?@action=redirect&bpo=45085

   (34) https://bugs.python.org/issue?@action=redirect&bpo=40360

   (35) https://peps.python.org/pep-0617/

   (36) https://bugs.python.org/issue?@action=redirect&bpo=45075

   (37) https://bugs.python.org/issue?@action=redirect&bpo=31299

   (38) https://bugs.python.org/issue?@action=redirect&bpo=41620

   (39) https://bugs.python.org/issue?@action=redirect&bpo=45021

   (40) https://bugs.python.org/issue?@action=redirect&bpo=43913

   (41) https://bugs.python.org/issue?@action=redirect&bpo=45030

   (42) https://bugs.python.org/issue?@action=redirect&bpo=45001

   (43) https://bugs.python.org/issue?@action=redirect&bpo=45010

   (44) https://bugs.python.org/issue?@action=redirect&bpo=39218

   (45) https://bugs.python.org/issue?@action=redirect&bpo=43613

   (46) https://bugs.python.org/issue?@action=redirect&bpo=37596

   (47) https://bugs.python.org/issue?@action=redirect&bpo=44019

   (48) https://bugs.python.org/issue?@action=redirect&bpo=42255

   (49) https://bugs.python.org/issue?@action=redirect&bpo=44955

   (50) https://bugs.python.org/issue?@action=redirect&bpo=39039

   (51) https://bugs.python.org/issue?@action=redirect&bpo=44935

   (52) https://bugs.python.org/issue?@action=redirect&bpo=44911

   (53) https://bugs.python.org/issue?@action=redirect&bpo=41322

   (54) https://bugs.python.org/issue?@action=redirect&bpo=44524

   (55) https://bugs.python.org/issue?@action=redirect&bpo=38956

   (56) https://bugs.python.org/issue?@action=redirect&bpo=44860

   (57) https://bugs.python.org/issue?@action=redirect&bpo=44859

   (58) https://bugs.python.org/issue?@action=redirect&bpo=44581

   (59) https://bugs.python.org/issue?@action=redirect&bpo=44849

   (60) https://bugs.python.org/issue?@action=redirect&bpo=44605

   (61) https://bugs.python.org/issue?@action=redirect&bpo=44524

   (62) https://bugs.python.org/issue?@action=redirect&bpo=44839

   (63) https://bugs.python.org/issue?@action=redirect&bpo=44822

   (64) https://bugs.python.org/issue?@action=redirect&bpo=44801

   (65) https://bugs.python.org/issue?@action=redirect&bpo=44806

   (66) https://bugs.python.org/issue?@action=redirect&bpo=27275

   (67) https://bugs.python.org/issue?@action=redirect&bpo=44793

   (68) https://bugs.python.org/issue?@action=redirect&bpo=44784

   (69) https://bugs.python.org/issue?@action=redirect&bpo=44667

   (70) https://bugs.python.org/issue?@action=redirect&bpo=44771

   (71) https://bugs.python.org/issue?@action=redirect&bpo=44752

   (72) https://bugs.python.org/issue?@action=redirect&bpo=44747

   (73) https://bugs.python.org/issue?@action=redirect&bpo=42378

   (74) https://bugs.python.org/issue?@action=redirect&bpo=44720

   (75) https://bugs.python.org/issue?@action=redirect&bpo=44704

   (76) https://bugs.python.org/issue?@action=redirect&bpo=44666

   (77) https://bugs.python.org/issue?@action=redirect&bpo=44688

   (78) https://bugs.python.org/issue?@action=redirect&bpo=44690

   (79) https://bugs.python.org/issue?@action=redirect&bpo=42854

   (80) https://bugs.python.org/issue?@action=redirect&bpo=44686

   (81) https://bugs.python.org/issue?@action=redirect&bpo=44353

   (82) https://bugs.python.org/issue?@action=redirect&bpo=44682

   (83) https://bugs.python.org/issue?@action=redirect&bpo=44353

   (84) https://bugs.python.org/issue?@action=redirect&bpo=44678

   (85) https://bugs.python.org/issue?@action=redirect&bpo=44524

   (86) https://bugs.python.org/issue?@action=redirect&bpo=40897

   (87) https://bugs.python.org/issue?@action=redirect&bpo=44638

   (88) https://bugs.python.org/issue?@action=redirect&bpo=44648

   (89) https://bugs.python.org/issue?@action=redirect&bpo=44608

   (90) https://bugs.python.org/issue?@action=redirect&bpo=44594

   (91) https://bugs.python.org/issue?@action=redirect&bpo=42799

   (92) https://bugs.python.org/issue?@action=redirect&bpo=41928

   (93) https://bugs.python.org/issue?@action=redirect&bpo=44569

   (94) https://bugs.python.org/issue?@action=redirect&bpo=44566

   (95) https://bugs.python.org/issue?@action=redirect&bpo=44558

   (96) https://bugs.python.org/issue?@action=redirect&bpo=41249

   (97) https://bugs.python.org/issue?@action=redirect&bpo=44554

   (98) https://bugs.python.org/issue?@action=redirect&bpo=34798

   (99) https://bugs.python.org/issue?@action=redirect&bpo=44539

   (100) https://bugs.python.org/issue?@action=redirect&bpo=44461

   (101) https://bugs.python.org/issue?@action=redirect&bpo=43625

   (102) https://bugs.python.org/issue?@action=redirect&bpo=44516

   (103) https://bugs.python.org/issue?@action=redirect&bpo=42892

   (104) https://bugs.python.org/issue?@action=redirect&bpo=44468

   (105) https://bugs.python.org/issue?@action=redirect&bpo=44491

   (106) https://bugs.python.org/issue?@action=redirect&bpo=43977

   (107) https://bugs.python.org/issue?@action=redirect&bpo=44482

   (108) https://bugs.python.org/issue?@action=redirect&bpo=44466

   (109) https://bugs.python.org/issue?@action=redirect&bpo=44471

   (110) https://bugs.python.org/issue?@action=redirect&bpo=44404

   (111) https://bugs.python.org/issue?@action=redirect&bpo=41546

   (112) https://bugs.python.org/issue?@action=redirect&bpo=44458

   (113) https://bugs.python.org/issue?@action=redirect&bpo=44464

   (114) https://bugs.python.org/issue?@action=redirect&bpo=44446

   (115) https://bugs.python.org/issue?@action=redirect&bpo=44439

   (116) https://bugs.python.org/issue?@action=redirect&bpo=44434

   (117) https://bugs.python.org/issue?@action=redirect&bpo=42972

   (118) https://bugs.python.org/issue?@action=redirect&bpo=44422

   (119) https://bugs.python.org/issue?@action=redirect&bpo=38291

   (120) https://bugs.python.org/issue?@action=redirect&bpo=37880

   (121) https://bugs.python.org/issue?@action=redirect&bpo=44389

   (122) https://bugs.python.org/issue?@action=redirect&bpo=27827

   (123) https://bugs.python.org/issue?@action=redirect&bpo=44395

   (124) https://bugs.python.org/issue?@action=redirect&bpo=34266

   (125) https://bugs.python.org/issue?@action=redirect&bpo=44362

   (126) https://bugs.python.org/issue?@action=redirect&bpo=44342

   (127) https://bugs.python.org/issue?@action=redirect&bpo=44356

   (128) https://bugs.python.org/issue?@action=redirect&bpo=44351

   (129) https://bugs.python.org/issue?@action=redirect&bpo=35800

   (130) https://bugs.python.org/issue?@action=redirect&bpo=44357

   (131) https://bugs.python.org/issue?@action=redirect&bpo=44339

   (132) https://bugs.python.org/issue?@action=redirect&bpo=44242

   (133) https://bugs.python.org/issue?@action=redirect&bpo=44246

   (134) https://bugs.python.org/issue?@action=redirect&bpo=44246

   (135) https://bugs.python.org/issue?@action=redirect&bpo=43858

   (136) https://bugs.python.org/issue?@action=redirect&bpo=44260

   (137) https://bugs.python.org/issue?@action=redirect&bpo=44254

   (138) https://bugs.python.org/issue?@action=redirect&bpo=44258

   (139) https://bugs.python.org/issue?@action=redirect&bpo=44235

   (140) https://bugs.python.org/issue?@action=redirect&bpo=38693

   (141) https://bugs.python.org/issue?@action=redirect&bpo=33693

   (142) https://bugs.python.org/issue?@action=redirect&bpo=44241

   (143) https://bugs.python.org/issue?@action=redirect&bpo=43216

   (144) https://bugs.python.org/issue?@action=redirect&bpo=44210

   (145) https://bugs.python.org/issue?@action=redirect&bpo=43643

   (146) https://bugs.python.org/issue?@action=redirect&bpo=27334

   (147) https://bugs.python.org/issue?@action=redirect&bpo=4928

   (148) https://bugs.python.org/issue?@action=redirect&bpo=44154

   (149) https://bugs.python.org/issue?@action=redirect&bpo=33433

   (150) https://datatracker.ietf.org/doc/html/rfc4291.html

   (151) https://bugs.python.org/issue?@action=redirect&bpo=44150

   (152) https://bugs.python.org/issue?@action=redirect&bpo=44142

   (153) https://bugs.python.org/issue?@action=redirect&bpo=44145

   (154) https://bugs.python.org/issue?@action=redirect&bpo=44095

   (155) https://bugs.python.org/issue?@action=redirect&bpo=44077

   (156) https://bugs.python.org/issue?@action=redirect&bpo=37788

   (157) https://bugs.python.org/issue?@action=redirect&bpo=38908

   (158) https://bugs.python.org/issue?@action=redirect&bpo=44098

   (159) https://peps.python.org/pep-0612/

   (160) https://bugs.python.org/issue?@action=redirect&bpo=44089

   (161) https://bugs.python.org/issue?@action=redirect&bpo=44081

   (162) https://bugs.python.org/issue?@action=redirect&bpo=44061

   (163) https://bugs.python.org/issue?@action=redirect&bpo=44059

   (164) https://bugs.python.org/issue?@action=redirect&bpo=36515

   (165) https://bugs.python.org/issue?@action=redirect&bpo=40465

   (166) https://bugs.python.org/issue?@action=redirect&bpo=44018

   (167) https://bugs.python.org/issue?@action=redirect&bpo=38352

   (168) https://bugs.python.org/issue?@action=redirect&bpo=44002

   (169) https://bugs.python.org/issue?@action=redirect&bpo=43972

   (170) https://bugs.python.org/issue?@action=redirect&bpo=28528

   (171) https://bugs.python.org/issue?@action=redirect&bpo=43853

   (172) https://bugs.python.org/issue?@action=redirect&bpo=43666

   (173) https://bugs.python.org/issue?@action=redirect&bpo=43650

   (174) https://bugs.python.org/issue?@action=redirect&bpo=43612

   (175) https://bugs.python.org/issue?@action=redirect&bpo=43392

   (176) https://bugs.python.org/issue?@action=redirect&bpo=43318

   (177) https://bugs.python.org/issue?@action=redirect&bpo=43234

   (178) https://bugs.python.org/issue?@action=redirect&bpo=43232

   (179) https://bugs.python.org/issue?@action=redirect&bpo=30077

   (180) https://bugs.python.org/issue?@action=redirect&bpo=42971

   (181) https://bugs.python.org/issue?@action=redirect&bpo=43086

   (182) https://bugs.python.org/issue?@action=redirect&bpo=43024

   (183) https://bugs.python.org/issue?@action=redirect&bpo=33809

   (184) https://bugs.python.org/issue?@action=redirect&bpo=42862

   (185) https://bugs.python.org/issue?@action=redirect&bpo=41818

   (186) https://bugs.python.org/issue?@action=redirect&bpo=40497

   (187) https://bugs.python.org/issue?@action=redirect&bpo=37449

   (188) https://bugs.python.org/issue?@action=redirect&bpo=40956

   (189) https://bugs.python.org/issue?@action=redirect&bpo=41730

   (190) https://bugs.python.org/issue?@action=redirect&bpo=20684

   (191) https://bugs.python.org/issue?@action=redirect&bpo=41402

   (192) https://bugs.python.org/issue?@action=redirect&bpo=32695

   (193) https://bugs.python.org/issue?@action=redirect&bpo=41137

   (194) https://bugs.python.org/issue?@action=redirect&bpo=24391

   (195) https://bugs.python.org/issue?@action=redirect&bpo=5846

   (196) https://bugs.python.org/issue?@action=redirect&bpo=40563

   (197) https://bugs.python.org/issue?@action=redirect&bpo=34990

   (198) https://bugs.python.org/issue?@action=redirect&bpo=39549

   (199) https://bugs.python.org/issue?@action=redirect&bpo=37022

   (200) https://bugs.python.org/issue?@action=redirect&bpo=38840

   (201) https://bugs.python.org/issue?@action=redirect&bpo=39359

   (202) https://bugs.python.org/issue?@action=redirect&bpo=38741

   (203) https://bugs.python.org/issue?@action=redirect&bpo=38415

   (204) https://bugs.python.org/issue?@action=redirect&bpo=30256

   (205) https://bugs.python.org/issue?@action=redirect&bpo=27513

   (206) https://bugs.python.org/issue?@action=redirect&bpo=16379

   (207) https://bugs.python.org/issue?@action=redirect&bpo=26228

   (208) https://bugs.python.org/issue?@action=redirect&bpo=33349

   (209) https://bugs.python.org/issue?@action=redirect&bpo=29298


File: python.info,  Node: Documentation<34>,  Next: Tests<37>,  Prev: Library<92>,  Up: Python 3 11 0 alpha 1

1.23.43.22 Documentation
........................

   - bpo-45216(1): Remove extra documentation listing methods in
     ‘difflib’.  It was rendering twice in pydoc and was outdated in
     some places.

   - bpo-45024(2): *note collections.abc: 1e. documentation has been
     expanded to explicitly cover how instance and subclass checks work,
     with additional doctest examples and an exhaustive list of ABCs
     which test membership purely by presence of the right *note special
     method: 1a06.s.  Patch by Raymond Hettinger.

   - bpo-44957(3): Promote PEP 604 union syntax by using it where
     possible.  Also, mention ‘X | Y’ more prominently in section about
     ‘Union’ and mention ‘X | None’ at all in section about ‘Optional’.

   - bpo-16580(4): Added code equivalents for the *note int.to_bytes():
     19d8. and *note int.from_bytes(): 198d. methods, as well as tests
     ensuring that these code equivalents are valid.

   - bpo-44903(5): Removed the ‘othergui.rst’ file, any references to
     it, and the list of GUI frameworks in the FAQ. In their place I’ve
     added links to the Python Wiki page on GUI frameworks(6).

   - bpo-33479(7): Tkinter documentation has been greatly expanded with
     new “Architecture” and “Threading model” sections.

   - bpo-36700(8): *note base64: e. RFC references were updated to point
     to RFC 4648(9); a section was added to point users to the new
     “security considerations” section of the RFC.

   - bpo-44740(10): Replaced occurrences of uppercase “Web” and
     “Internet” with lowercase versions per the 2016 revised Associated
     Press Style Book.

   - bpo-44693(11): Update the definition of __future__ in the glossary
     by replacing the confusing word “pseudo-module” with a more
     accurate description.

   - bpo-35183(12): Add typical examples to os.path.splitext docs

   - bpo-30511(13): Clarify that *note shutil.make_archive(): 4b6. is
     not thread-safe due to reliance on changing the current working
     directory.

   - bpo-44561(14): Update of three expired hyperlinks in
     Doc/distributing/index.rst: “Project structure”, “Building and
     packaging the project”, and “Uploading the project to the Python
     Packaging Index”.

   - bpo-44651(15): Delete entry “coercion” in Doc/glossary.rst for its
     outdated definition.

   - bpo-42958(16): Updated the docstring and docs of *note
     filecmp.cmp(): 1771. to be more accurate and less confusing
     especially in respect to 'shallow' arg.

   - bpo-44631(17): Refactored the ‘repr()’ code of the ‘_Environ’ (os
     module).

   - bpo-44613(18): importlib.metadata is no longer provisional.

   - bpo-44558(19): Match the docstring and python implementation of
     *note countOf(): 8e5. to the behavior of its c implementation.

   - bpo-44544(20): List all kwargs for *note textwrap.wrap(): 1516,
     *note textwrap.fill(): 1515, and *note textwrap.shorten(): 100b.
     Now, there are nav links to attributes of ‘TextWrap’, which makes
     navigation much easier while minimizing duplication in the
     documentation.

   - bpo-38062(21): Clarify that atexit uses equality comparisons
     internally.

   - bpo-40620(22): Convert examples in tutorial controlflow.rst section
     4.3 to be interpreter-demo style.

   - bpo-43066(23): Added a warning to *note zipfile: 131. docs:
     filename arg with a leading slash may cause archive to be
     un-openable on Windows systems.

   - bpo-39452(24): Rewrote ‘Doc/library/__main__.rst’.  Broadened scope
     of the document to explicitly discuss and differentiate between
     ‘__main__.py’ in packages versus the ‘__name__ == '__main__'’
     expression (and the idioms that surround it).

   - bpo-13814(25): In the Design FAQ, answer “Why don’t generators
     support the with statement?”

   - bpo-27752(26): Documentation of csv.Dialect is more descriptive.

   - bpo-44453(27): Fix documentation for the return type of *note
     sysconfig.get_path(): 1378.

   - bpo-44392(28): Added a new section in the C API documentation for
     types used in type hinting.  Documented ‘Py_GenericAlias’ and
     ‘Py_GenericAliasType’.

   - bpo-38291(29): Mark ‘typing.io’ and ‘typing.re’ as deprecated since
     Python 3.8 in the documentation.  They were never properly
     supported by type checkers.

   - bpo-44322(30): Document that SyntaxError args have a details tuple
     and that details are adjusted for errors in f-string field
     replacement expressions.

   - bpo-42392(31): Document the deprecation and removal of the ‘loop’
     parameter for many functions and classes in *note asyncio: a.

   - bpo-44195(32): Corrected references to ‘TraversableResources’ in
     docs.  There is no ‘TraversableReader’.

   - bpo-41963(33): Document that ‘ConfigParser’ strips off comments
     when reading configuration files.

   - bpo-44072(34): Correct where in the numeric ABC hierarchy ‘**’
     support is added, i.e., in numbers.Complex, not numbers.Integral.

   - bpo-43558(35): Add the remark to *note dataclasses: 2f.
     documentation that the ‘__init__()’ of any base class has to be
     called in ‘__post_init__()’, along with a code example.

   - bpo-44025(36): Clarify when ‘_’ in match statements is a keyword,
     and when not.

   - bpo-41706(37): Fix docs about how methods like ‘__add__’ are
     invoked when evaluating operator expressions.

   - bpo-41621(38): Document that *note collections.defaultdict: 1201.
     parameter ‘default_factory’ defaults to ‘None’ and is
     positional-only.

   - bpo-41576(39): document BaseException in favor of bare except

   - bpo-21760(40): The description for __file__ fixed.  Patch by Furkan
     Onder

   - bpo-39498(41): Add a “Security Considerations” index which links to
     standard library modules that have explicitly documented security
     considerations.

   - bpo-33479(42): Remove the unqualified claim that tkinter is
     threadsafe.  It has not been true for several years and likely
     never was.  An explanation of what is true may be added later,
     after more discussion, and possibly after patching _tkinter.c,

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45216

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45024

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44957

   (4) https://bugs.python.org/issue?@action=redirect&bpo=16580

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44903

   (6) https://wiki.python.org/moin/GuiProgramming

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33479

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36700

   (9) https://datatracker.ietf.org/doc/html/rfc4648.html

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44740

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44693

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35183

   (13) https://bugs.python.org/issue?@action=redirect&bpo=30511

   (14) https://bugs.python.org/issue?@action=redirect&bpo=44561

   (15) https://bugs.python.org/issue?@action=redirect&bpo=44651

   (16) https://bugs.python.org/issue?@action=redirect&bpo=42958

   (17) https://bugs.python.org/issue?@action=redirect&bpo=44631

   (18) https://bugs.python.org/issue?@action=redirect&bpo=44613

   (19) https://bugs.python.org/issue?@action=redirect&bpo=44558

   (20) https://bugs.python.org/issue?@action=redirect&bpo=44544

   (21) https://bugs.python.org/issue?@action=redirect&bpo=38062

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40620

   (23) https://bugs.python.org/issue?@action=redirect&bpo=43066

   (24) https://bugs.python.org/issue?@action=redirect&bpo=39452

   (25) https://bugs.python.org/issue?@action=redirect&bpo=13814

   (26) https://bugs.python.org/issue?@action=redirect&bpo=27752

   (27) https://bugs.python.org/issue?@action=redirect&bpo=44453

   (28) https://bugs.python.org/issue?@action=redirect&bpo=44392

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38291

   (30) https://bugs.python.org/issue?@action=redirect&bpo=44322

   (31) https://bugs.python.org/issue?@action=redirect&bpo=42392

   (32) https://bugs.python.org/issue?@action=redirect&bpo=44195

   (33) https://bugs.python.org/issue?@action=redirect&bpo=41963

   (34) https://bugs.python.org/issue?@action=redirect&bpo=44072

   (35) https://bugs.python.org/issue?@action=redirect&bpo=43558

   (36) https://bugs.python.org/issue?@action=redirect&bpo=44025

   (37) https://bugs.python.org/issue?@action=redirect&bpo=41706

   (38) https://bugs.python.org/issue?@action=redirect&bpo=41621

   (39) https://bugs.python.org/issue?@action=redirect&bpo=41576

   (40) https://bugs.python.org/issue?@action=redirect&bpo=21760

   (41) https://bugs.python.org/issue?@action=redirect&bpo=39498

   (42) https://bugs.python.org/issue?@action=redirect&bpo=33479


File: python.info,  Node: Tests<37>,  Next: Build<41>,  Prev: Documentation<34>,  Up: Python 3 11 0 alpha 1

1.23.43.23 Tests
................

   - bpo-40173(1): Fix *note
     test.support.import_helper.import_fresh_module(): 1a08.

   - bpo-45280(2): Add a test case for empty *note typing.NamedTuple:
     2b0.

   - bpo-45269(3): Cover case when invalid ‘markers’ type is supplied to
     ‘c_make_encoder’.

   - bpo-45128(4): Fix ‘test_multiprocessing_fork’ failure due to
     ‘test_logging’ and ‘sys.modules’ manipulation.

   - bpo-45209(5): Fix ‘UserWarning: resource_tracker’ warning in
     ‘_test_multiprocessing._TestSharedMemory.test_shared_memory_cleaned_after_process_termination’

   - bpo-45185(6): Enables ‘TestEnumerations’ test cases in ‘test_ssl’
     suite.

   - bpo-45195(7): Fix test_readline.test_nonascii(): sometimes, the
     newline character is not written at the end, so don’t expect it in
     the output.  Patch by Victor Stinner.

   - bpo-45156(8): Fixes infinite loop on *note unittest.mock.seal():
     bbf. of mocks created by ‘create_autospec()’.

   - bpo-45125(9): Improves pickling tests and docs of ‘SharedMemory’
     and ‘SharableList’ objects.

   - bpo-44860(10): Update ‘test_sysconfig.test_user_similar()’ for the
     posix_user scheme: ‘platlib’ doesn’t use *note sys.platlibdir: 942.
     Patch by Victor Stinner.

   - bpo-45052(11):
     ‘WithProcessesTestSharedMemory.test_shared_memory_basics’ test was
     ignored, because ‘self.assertEqual(sms.size, sms2.size)’ line was
     failing.  It is now removed and test is unskipped.

     The main motivation for this line to be removed from the test is
     that the ‘size’ of ‘SharedMemory’ is not ever guaranteed to be the
     same.  It is decided by the platform.

   - bpo-44895(12): libregrtest now clears the type cache later to
     reduce the risk of false alarm when checking for reference leaks.
     Previously, the type cache was cleared too early and libregrtest
     raised a false alarm about reference leaks under very specific
     conditions.  Patch by Irit Katriel and Victor Stinner.

   - bpo-45042(13): Fixes that test classes decorated with
     ‘@hashlib_helper.requires_hashdigest’ were skipped all the time.

   - bpo-25130(14): Add calls of *note gc.collect(): a47. in tests to
     support PyPy.

   - bpo-45011(15): Made tests relying on the ‘_asyncio’ C extension
     module optional to allow running on alternative Python
     implementations.  Patch by Serhiy Storchaka.

   - bpo-44949(16): Fix auto history tests of test_readline: sometimes,
     the newline character is not written at the end, so don’t expect it
     in the output.

   - bpo-44891(17): Tests were added to clarify *note id(): 1471. is
     preserved when ‘obj * 1’ is used on *note str: 44f. and *note
     bytes: 1c2. objects.  Patch by Nikita Sobolev.

   - bpo-44852(18): Add ability to wholesale silence DeprecationWarnings
     while running the regression test suite.

   - bpo-40928(19): Notify users running test_decimal regression tests
     on macOS of potential harmless “malloc can’t allocate region”
     messages spewed by test_decimal.

   - bpo-44734(20): Fixed floating-point precision issue in turtle
     tests.

   - bpo-44708(21): Regression tests, when run with -w, are now
     re-running only the affected test methods instead of re-running the
     entire test file.

   - bpo-42095(22): Added interop tests for Apple plists: generate plist
     files with Python plistlib and parse with Apple plutil; and the
     other way round.

   - bpo-44647(23): Added a permanent Unicode-valued environment
     variable to regression tests to ensure they handle this use case in
     the future.  If your test environment breaks because of that,
     report a bug to us, and temporarily set
     PYTHONREGRTEST_UNICODE_GUARD=0 in your test environment.

   - bpo-44515(24): Adjust recently added contextlib tests to avoid
     assuming the use of a refcounted GC

   - bpo-44287(25): Fix asyncio test_popen() of test_windows_utils by
     using a longer timeout.  Use military grade battle-tested *note
     test.support.SHORT_TIMEOUT: 1a09. timeout rather than a hardcoded
     timeout of 10 seconds: it’s 30 seconds by default, but it is made
     longer on slow buildbots.  Patch by Victor Stinner.

   - bpo-44451(26): Reset ‘DeprecationWarning’ filters in
     ‘test.test_importlib.test_metadata_api.APITests.test_entry_points_by_index’
     to avoid ‘StopIteration’ error if ‘DeprecationWarnings’ are
     ignored.

   - bpo-44363(27): Account for address sanitizer in test_capi.
     test_capi now passes when run GCC address sanitizer.

   - bpo-44364(28): Add non integral tests for *note math.sqrt(): a11.
     function.

   - bpo-43921(29): Fix test_ssl.test_wrong_cert_tls13(): use
     ‘suppress_ragged_eofs=False’, since ‘read()’ can raise *note
     ssl.SSLEOFError: 185c. on Windows.  Patch by Victor Stinner.

   - bpo-43921(30): Fix test_pha_required_nocert() of test_ssl: catch
     two more EOF cases (when the ‘recv()’ method returns an empty
     string).  Patch by Victor Stinner.

   - bpo-44131(31): Add test_frozenmain to test_embed to test the
     ‘Py_FrozenMain()’ C function.  Patch by Victor Stinner.

   - bpo-31904(32): Ignore error string case in test_file_not_exists().

   - bpo-42083(33): Add test to check that ‘PyStructSequence_NewType’
     accepts a ‘PyStructSequence_Desc’ with ‘doc’ field set to ‘NULL’.

   - bpo-35753(34): Fix crash in doctest when doctest parses modules
     that include unwrappable functions by skipping those functions.

   - bpo-30256(35): Add test for nested queues when using
     ‘multiprocessing’ shared objects ‘AutoProxy[Queue]’ inside
     ‘ListProxy’ and ‘DictProxy’

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40173

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45280

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45269

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45128

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45209

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45185

   (7) https://bugs.python.org/issue?@action=redirect&bpo=45195

   (8) https://bugs.python.org/issue?@action=redirect&bpo=45156

   (9) https://bugs.python.org/issue?@action=redirect&bpo=45125

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44860

   (11) https://bugs.python.org/issue?@action=redirect&bpo=45052

   (12) https://bugs.python.org/issue?@action=redirect&bpo=44895

   (13) https://bugs.python.org/issue?@action=redirect&bpo=45042

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25130

   (15) https://bugs.python.org/issue?@action=redirect&bpo=45011

   (16) https://bugs.python.org/issue?@action=redirect&bpo=44949

   (17) https://bugs.python.org/issue?@action=redirect&bpo=44891

   (18) https://bugs.python.org/issue?@action=redirect&bpo=44852

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40928

   (20) https://bugs.python.org/issue?@action=redirect&bpo=44734

   (21) https://bugs.python.org/issue?@action=redirect&bpo=44708

   (22) https://bugs.python.org/issue?@action=redirect&bpo=42095

   (23) https://bugs.python.org/issue?@action=redirect&bpo=44647

   (24) https://bugs.python.org/issue?@action=redirect&bpo=44515

   (25) https://bugs.python.org/issue?@action=redirect&bpo=44287

   (26) https://bugs.python.org/issue?@action=redirect&bpo=44451

   (27) https://bugs.python.org/issue?@action=redirect&bpo=44363

   (28) https://bugs.python.org/issue?@action=redirect&bpo=44364

   (29) https://bugs.python.org/issue?@action=redirect&bpo=43921

   (30) https://bugs.python.org/issue?@action=redirect&bpo=43921

   (31) https://bugs.python.org/issue?@action=redirect&bpo=44131

   (32) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (33) https://bugs.python.org/issue?@action=redirect&bpo=42083

   (34) https://bugs.python.org/issue?@action=redirect&bpo=35753

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30256


File: python.info,  Node: Build<41>,  Next: Windows<35>,  Prev: Tests<37>,  Up: Python 3 11 0 alpha 1

1.23.43.24 Build
................

   - bpo-45220(1): Avoid building with the Windows 11 SDK previews
     automatically.  This may be overridden by setting the
     ‘DefaultWindowsSDKVersion’ environment variable before building.

   - bpo-45020(2): Freeze stdlib modules that are imported during
     startup.  This provides significant performance improvements to
     startup.  If necessary, use the previously added “-X
     frozen_modules=off” commandline option to force importing the
     source modules.

   - bpo-45188(3): Windows builds now regenerate frozen modules as the
     first part of the build.  Previously the regeneration was later in
     the build, which would require it to be restarted if any modules
     had changed.

   - bpo-45163(4): Fixes Haiku platform build.

   - bpo-45067(5): The ncurses function extended_color_content was
     introduced in 2017

     (‘https://invisible-island.net/ncurses/NEWS.html#index-t20170401’).
     The

     ncurses-devel package in CentOS 7 had a older version ncurses
     resulted in compilation error.  For compiling ncurses with extended
     color support, we verify the version of the ncurses library >=
     20170401.

   - bpo-45019(6): Generate lines in relevant files for frozen modules.
     Up until now each of the files had to be edited manually.  This
     change makes it easier to add to and modify the frozen modules.

   - bpo-44340(7): Add support for building with clang thin lto via
     –with-lto=thin/full.  Patch by Donghee Na and Brett Holman.

   - bpo-44535(8): Enable building using a Visual Studio 2022 install on
     Windows.

   - bpo-43298(9): Improved error message when building without a
     Windows SDK installed.

   - bpo-44381(10): The Windows build now accepts
     ‘EnableControlFlowGuard’ set to ‘guard’ to enable CFG.

   - bpo-41282(11): Fix broken ‘make install’ that caused standard
     library extension modules to be unnecessarily and incorrectly
     rebuilt during the install phase of cpython.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45220

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45020

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45188

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45163

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45067

   (6) https://bugs.python.org/issue?@action=redirect&bpo=45019

   (7) https://bugs.python.org/issue?@action=redirect&bpo=44340

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44535

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43298

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44381

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41282


File: python.info,  Node: Windows<35>,  Next: macOS<27>,  Prev: Build<41>,  Up: Python 3 11 0 alpha 1

1.23.43.25 Windows
..................

   - bpo-45375(1): Fixes an assertion failure due to searching for the
     standard library in unnormalised paths.

   - bpo-45022(2): Update Windows release to include libffi 3.4.2

   - bpo-45007(3): Update to OpenSSL 1.1.1l in Windows build

   - bpo-44848(4): Upgrade Windows installer to use SQLite 3.36.0.

   - bpo-44572(5): Avoid consuming standard input in the *note platform:
     aa. module

   - bpo-44582(6): Accelerate speed of *note mimetypes: 8f.
     initialization using a native implementation of the registry scan.

   - bpo-41299(7): Fix 16 milliseconds jitter when using timeouts in
     *note threading: ed, such as with *note threading.Lock.acquire():
     69b. or *note threading.Condition.wait(): 1a0c.

   - bpo-42686(8): Build *note sqlite3: cf. with math functions enabled.
     Patch by Erlend E. Aasland.

   - bpo-40263(9): This is a follow-on bug from
     ‘https://bugs.python.org/issue26903’.  Once that is applied we run
     into an off-by-one assertion problem.  The assert was not correct.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45375

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45022

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45007

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44848

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44572

   (6) https://bugs.python.org/issue?@action=redirect&bpo=44582

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41299

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42686

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40263


File: python.info,  Node: macOS<27>,  Next: IDLE<23>,  Prev: Windows<35>,  Up: Python 3 11 0 alpha 1

1.23.43.26 macOS
................

   - bpo-45007(1): Update macOS installer builds to use OpenSSL 1.1.1l.

   - bpo-34602(2): When building CPython on macOS with ‘./configure
     --with-undefined-behavior-sanitizer --with-pydebug’, the stack size
     is now quadrupled to allow for the entire test suite to pass.

   - bpo-44848(3): Update macOS installer to use SQLite 3.36.0.

   - bpo-44689(4): *note ctypes.util.find_library(): d72. now works
     correctly on macOS 11 Big Sur even if Python is built on an older
     version of macOS. Previously, when built on older macOS systems,
     ‘find_library’ was not able to find macOS system libraries when
     running on Big Sur due to changes in how system libraries are
     stored.

   - bpo-41972(5): The framework build’s user header path in sysconfig
     is changed to add a ‘pythonX.Y’ component to match distutils’s
     behavior.

   - bpo-43109(6): Allow –with-lto configure option to work with
     Apple-supplied Xcode or Command Line Tools.

   - bpo-34932(7): Add socket.TCP_KEEPALIVE support for macOS. Patch by
     Shane Harvey.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45007

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34602

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44848

   (4) https://bugs.python.org/issue?@action=redirect&bpo=44689

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41972

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43109

   (7) https://bugs.python.org/issue?@action=redirect&bpo=34932


File: python.info,  Node: IDLE<23>,  Next: Tools/Demos<20>,  Prev: macOS<27>,  Up: Python 3 11 0 alpha 1

1.23.43.27 IDLE
...............

   - bpo-45296(1): On Windows, change exit/quit message to suggest
     Ctrl-D, which works, instead of <Ctrl-Z Return>, which does not
     work in IDLE.

   - bpo-45193(2): Make completion boxes appear on Ubuntu again.

   - bpo-40128(3): Mostly fix completions on macOS when not using tcl/tk
     8.6.11 (as with 3.9).  The added update_idletask call should be
     harmless and possibly helpful otherwise.

   - bpo-33962(4): Move the indent space setting from the Font tab to
     the new Windows tab.  Patch by Mark Roseman and Terry Jan Reedy.

   - bpo-40468(5): Split the settings dialog General tab into Windows
     and Shell/ED tabs.  Move help sources, which extend the Help menu,
     to the Extensions tab.  Make space for new options and shorten the
     dialog.  The latter makes the dialog better fit small screens.

   - bpo-41611(6): Avoid uncaught exceptions in
     ‘AutoCompleteWindow.winconfig_event()’.

   - bpo-41611(7): Fix IDLE sometimes freezing upon tab-completion on
     macOS.

   - bpo-44010(8): Highlight the new *note match: 813. statement’s *note
     soft keywords: 812.: *note match: 813, ‘case’, and *note _: 814.
     However, this highlighting is not perfect and will be incorrect in
     some rare cases, including some ‘_’-s in ‘case’ patterns.

   - bpo-44026(9): Include interpreter’s typo fix suggestions in message
     line for NameErrors and AttributeErrors.  Patch by E. Paine.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=45296

   (2) https://bugs.python.org/issue?@action=redirect&bpo=45193

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40128

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33962

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40468

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41611

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41611

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44010

   (9) https://bugs.python.org/issue?@action=redirect&bpo=44026


File: python.info,  Node: Tools/Demos<20>,  Next: C API<36>,  Prev: IDLE<23>,  Up: Python 3 11 0 alpha 1

1.23.43.28 Tools/Demos
......................

   - bpo-44786(1): Fix a warning in regular expression in the c-analyzer
     script.

   - bpo-44967(2): pydoc now returns a non-zero status code when a
     module cannot be found.

   - bpo-44978(3): Allow the Argument Clinic tool to handle
     ‘__complex__’ special methods.

   - bpo-43425(4): Removed the ‘test2to3’ demo project that demonstrated
     using lib2to3 to support Python 2.x and Python 3.x from a single
     source in a distutils package.  Patch by Donghee Na

   - bpo-44074(5): Make patchcheck automatically detect the correct base
     branch name (previously it was hardcoded to ‘master’)

   - bpo-20291(6): Added support for variadic positional parameters in
     Argument Clinic.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44786

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44967

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44978

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43425

   (5) https://bugs.python.org/issue?@action=redirect&bpo=44074

   (6) https://bugs.python.org/issue?@action=redirect&bpo=20291


File: python.info,  Node: C API<36>,  Prev: Tools/Demos<20>,  Up: Python 3 11 0 alpha 1

1.23.43.29 C API
................

   - bpo-41710(1): The PyThread_acquire_lock_timed() function now clamps
     the timeout if it is too large, rather than aborting the process.
     Patch by Victor Stinner.

   - bpo-44687(2): ‘BufferedReader.peek()’ no longer raises *note
     ValueError: 202. when the entire file has already been buffered.

   - bpo-45116(3): Add the *note Py_ALWAYS_INLINE: 1a11. macro to ask
     the compiler to always inline a static inline function.  The
     compiler can ignore it and decides to not inline the function.
     Patch by Victor Stinner.

   - bpo-45094(4): Add the *note Py_NO_INLINE: 1a12. macro to disable
     inlining on a function.  Patch by Victor Stinner.

   - bpo-45061(5): Add a deallocator to the *note bool: 46b. type to
     detect refcount bugs in C extensions which call
     ‘Py_DECREF(Py_True);’ or ‘Py_DECREF(Py_False);’ by mistake.  Patch
     by Victor Stinner.

   - bpo-42035(6): Add a new *note PyType_GetQualName(): 756. function
     to get type’s qualified name.

   - bpo-41103(7): Reverts removal of the old buffer protocol because
     they are part of stable ABI.

   - bpo-44751(8): Remove ‘crypt.h’ include from the public ‘Python.h’
     header.

   - bpo-42747(9): The ‘Py_TPFLAGS_HAVE_VERSION_TAG’ type flag now does
     nothing.  The ‘Py_TPFLAGS_HAVE_AM_SEND’ flag (which was added in
     3.10) is removed.  Both were unnecessary because it is not possible
     to have type objects with the relevant fields missing.

   - bpo-44530(10): Added the ‘co_qualname’ to the ‘PyCodeObject’
     structure to propagate the qualified name from the compiler to code
     objects.

     Patch by Gabriele N. Tornetta

   - bpo-44441(11): *note Py_RunMain(): 9d0. now resets *note
     PyImport_Inittab: 18be. to its initial value at exit.  It must be
     possible to call *note PyImport_AppendInittab(): 18bf. or *note
     PyImport_ExtendInittab(): 18c0. at each Python initialization.
     Patch by Victor Stinner.

   - bpo-39947(12): Remove 4 private trashcan C API functions which were
     only kept for the backward compatibility of the stable ABI with
     Python 3.8 and older, since the trashcan API was not usable with
     the limited C API on Python 3.8 and older.  The trashcan API was
     excluded from the limited C API in Python 3.9.

     Removed functions:

        * _PyTrash_deposit_object()

        * _PyTrash_destroy_chain()

        * _PyTrash_thread_deposit_object()

        * _PyTrash_thread_destroy_chain()

     The trashcan C API was never usable with the limited C API, since
     old trashcan macros accessed directly *note PyThreadState: 790.
     members like ‘_tstate->trash_delete_nesting’, whereas the
     ‘PyThreadState’ structure is opaque in the limited C API.

     Exclude also the ‘PyTrash_UNWIND_LEVEL’ constant from the C API.

     Patch by Victor Stinner.

   - bpo-40939(13): Removed documentation for the removed ‘PyParser_*’ C
     API.

   - bpo-43795(14): The list in *note Contents of Limited API: 79d. now
     shows the public name *note PyFrameObject: 78c. rather than
     ‘_frame’.  The non-existing entry ‘_node’ no longer appears in the
     list.

   - bpo-44378(15): *note Py_IS_TYPE(): 1946. no longer uses *note
     Py_TYPE(): 783. to avoid a compiler warning: no longer cast ‘const
     PyObject*’ to ‘PyObject*’.  Patch by Victor Stinner.

   - bpo-39573(16): Convert the *note Py_TYPE(): 783. and *note
     Py_SIZE(): 785. macros to static inline functions.  The *note
     Py_SET_TYPE(): 784. and *note Py_SET_SIZE(): 786. functions must
     now be used to set an object type and size.  Patch by Victor
     Stinner.

   - bpo-44263(17): The *note PyType_Ready(): 77f. function now raises
     an error if a type is defined with the *note Py_TPFLAGS_HAVE_GC:
     780. flag set but has no traverse function (*note
     PyTypeObject.tp_traverse: 781.).  Patch by Victor Stinner.

   - bpo-43795(18): The undocumented function ‘Py_FrozenMain()’ is
     removed from the Limited API.

   - bpo-44113(19): Deprecate the following functions to configure the
     Python initialization:

        * ‘PySys_AddWarnOptionUnicode()’

        * ‘PySys_AddWarnOption()’

        * ‘PySys_AddXOption()’

        * ‘PySys_HasWarnOptions()’

        * ‘Py_SetPath()’

        * ‘Py_SetProgramName()’

        * ‘Py_SetPythonHome()’

        * ‘Py_SetStandardStreamEncoding()’

        * ‘_Py_SetProgramFullPath()’

     Use the new *note PyConfig: 3a9. API of the *note Python
     Initialization Configuration: 3aa. instead ( PEP 587(20)).

   - bpo-44094(21): Remove ‘PyErr_SetFromErrnoWithUnicodeFilename()’,
     ‘PyErr_SetFromWindowsErrWithUnicodeFilename()’, and
     ‘PyErr_SetExcFromWindowsErrWithUnicodeFilename()’.  They are not
     documented and have been deprecated since Python 3.3.

   - bpo-43795(22): *note PyCodec_Unregister(): 89e. is now properly
     exported as a function in the Windows Stable ABI DLL.

   - bpo-44029(23): Remove deprecated ‘Py_UNICODE’ APIs:
     ‘PyUnicode_Encode’, ‘PyUnicode_EncodeUTF7’, ‘PyUnicode_EncodeUTF8’,
     ‘PyUnicode_EncodeUTF16’, ‘PyUnicode_EncodeUTF32’,
     ‘PyUnicode_EncodeLatin1’, ‘PyUnicode_EncodeMBCS’,
     ‘PyUnicode_EncodeDecimal’, ‘PyUnicode_EncodeRawUnicodeEscape’,
     ‘PyUnicode_EncodeCharmap’, ‘PyUnicode_EncodeUnicodeEscape’,
     ‘PyUnicode_TransformDecimalToASCII’, ‘PyUnicode_TranslateCharmap’,
     ‘PyUnicodeEncodeError_Create’, ‘PyUnicodeTranslateError_Create’.
     See PEP 393(24) and PEP 624(25) for reference.

   - bpo-42035(26): Add a new *note PyType_GetName(): 755. function to
     get type’s short name.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41710

   (2) https://bugs.python.org/issue?@action=redirect&bpo=44687

   (3) https://bugs.python.org/issue?@action=redirect&bpo=45116

   (4) https://bugs.python.org/issue?@action=redirect&bpo=45094

   (5) https://bugs.python.org/issue?@action=redirect&bpo=45061

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42035

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41103

   (8) https://bugs.python.org/issue?@action=redirect&bpo=44751

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42747

   (10) https://bugs.python.org/issue?@action=redirect&bpo=44530

   (11) https://bugs.python.org/issue?@action=redirect&bpo=44441

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40939

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43795

   (15) https://bugs.python.org/issue?@action=redirect&bpo=44378

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (17) https://bugs.python.org/issue?@action=redirect&bpo=44263

   (18) https://bugs.python.org/issue?@action=redirect&bpo=43795

   (19) https://bugs.python.org/issue?@action=redirect&bpo=44113

   (20) https://peps.python.org/pep-0587/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=44094

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43795

   (23) https://bugs.python.org/issue?@action=redirect&bpo=44029

   (24) https://peps.python.org/pep-0393/

   (25) https://peps.python.org/pep-0624/

   (26) https://bugs.python.org/issue?@action=redirect&bpo=42035


File: python.info,  Node: Python 3 10 0 beta 1,  Next: Python 3 10 0 alpha 7,  Prev: Python 3 11 0 alpha 1,  Up: Changelog

1.23.44 Python 3.10.0 beta 1
----------------------------

'Release date: 2021-05-03'

* Menu:

* Security: Security<27>.
* Core and Builtins: Core and Builtins<91>.
* Library: Library<93>.
* Core and Builtins: Core and Builtins<92>.
* Library: Library<94>.
* Core and Builtins: Core and Builtins<93>.
* Library: Library<95>.
* Documentation: Documentation<35>.
* Tests: Tests<38>.
* Build: Build<42>.
* Windows: Windows<36>.
* macOS: macOS<28>.
* IDLE: IDLE<24>.
* C API: C API<37>.


File: python.info,  Node: Security<27>,  Next: Core and Builtins<91>,  Up: Python 3 10 0 beta 1

1.23.44.1 Security
..................

   - bpo-43434(1): Creating *note sqlite3.Connection: 245. objects now
     also produces ‘sqlite3.connect’ and ‘sqlite3.connect/handle’ *note
     auditing events: 1a15.  Previously these events were only produced
     by *note sqlite3.connect(): 2a8. calls.  Patch by Erlend E.
     Aasland.

   - bpo-43998(2): The *note ssl: d0. module sets more secure cipher
     suites defaults.  Ciphers without forward secrecy and with SHA-1
     MAC are disabled by default.  Security level 2 prohibits weak RSA,
     DH, and ECC keys with less than 112 bits of security.  *note
     SSLContext: 294. defaults to minimum protocol version TLS 1.2.
     Settings are based on Hynek Schlawack’s research.

   - bpo-43882(3): The presence of newline or tab characters in parts of
     a URL could allow some forms of attacks.

     Following the controlling specification for URLs defined by WHATWG
     *note urllib.parse(): 10a. now removes ASCII newlines and tabs from
     URLs, preventing such attacks.

   - bpo-43472(4): Ensures interpreter-level audit hooks receive the
     ‘cpython.PyInterpreterState_New’ event when called through the
     ‘_xxsubinterpreters’ module.

   - bpo-43362(5): Fix invalid free in _sha3 module.  The issue was
     introduced in 3.10.0a1.  Python 3.9 and earlier are not affected.

   - bpo-43762(6): Add audit events for ‘sqlite3.connect/handle()’,
     *note sqlite3.Connection.enable_load_extension(): 844, and *note
     sqlite3.Connection.load_extension(): 4bb.  Patch by Erlend E.
     Aasland.

   - bpo-43756(7): Add new audit event ‘glob.glob/2’ to incorporate the
     new 'root_dir' and 'dir_fd' arguments added to *note glob.glob():
     29f. and *note glob.iglob(): 80d.

   - bpo-36384(8): *note ipaddress: 80. module no longer accepts any
     leading zeros in IPv4 address strings.  Leading zeros are ambiguous
     and interpreted as octal notation by some libraries.  For example
     the legacy function *note socket.inet_aton(): 96b. treats leading
     zeros as octal notation.  glibc implementation of modern *note
     inet_pton(): 96c. does not accept any leading zeros.  For a while
     the ‘ipaddress’ module used to accept ambiguous leading zeros.

   - bpo-43075(9): Fix Regular Expression Denial of Service (ReDoS)
     vulnerability in *note urllib.request.AbstractBasicAuthHandler:
     1a16.  The ReDoS-vulnerable regex has quadratic worst-case
     complexity and it allows cause a denial of service when identifying
     crafted invalid RFCs.  This ReDoS issue is on the client side and
     needs remote attackers to control the HTTP server.

   - bpo-42800(10): Audit hooks are now fired for frame.f_code,
     traceback.tb_frame, and generator code/frame attribute access.

   - bpo-37363(11): Add audit events to the *note http.client: 6f.
     module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43434

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43998

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43882

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43472

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43362

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43762

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43756

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36384

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43075

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42800

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37363


File: python.info,  Node: Core and Builtins<91>,  Next: Library<93>,  Prev: Security<27>,  Up: Python 3 10 0 beta 1

1.23.44.2 Core and Builtins
...........................

   - bpo-43977(1): Prevent classes being both a sequence and a mapping
     when pattern matching.

   - bpo-43977(2): Use *note tp_flags: 1a18. on the class object to
     determine if the subject is a sequence or mapping when pattern
     matching.  Avoids the need to import *note collections.abc: 1e.
     when pattern matching.

   - bpo-43892(3): Restore proper validation of complex literal value
     patterns when parsing ‘match’ blocks.

   - bpo-43933(4): Set frame.f_lineno to the line number of the ‘with’
     kweyword when executing the call to ‘__exit__’.

   - bpo-43933(5): If the current position in a frame has no line number
     then set the f_lineno attribute to None, instead of -1, to conform
     to PEP 626.  This should not normally be possible, but might occur
     in some unusual circumstances.

   - bpo-43963(6): Importing the ‘_signal’ module in a subinterpreter
     has no longer side effects.

   - bpo-42739(7): The internal representation of line number tables is
     changed to not use sentinels, and an explicit length parameter is
     added to the out of process API function
     ‘PyLineTable_InitAddressRange’.  This makes the handling of line
     number tables more robust in some circumstances.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43977

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43977

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43892

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43933

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43933

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43963

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42739


File: python.info,  Node: Library<93>,  Next: Core and Builtins<92>,  Prev: Core and Builtins<91>,  Up: Python 3 10 0 beta 1

1.23.44.3 Library
.................

   - bpo-43908(1): Make *note re: b9. types immutable.  Patch by Erlend
     E. Aasland.

   - bpo-43908(2): Make the *note array.array: 1a0. type immutable.
     Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43908

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43908


File: python.info,  Node: Core and Builtins<92>,  Next: Library<94>,  Prev: Library<93>,  Up: Python 3 10 0 beta 1

1.23.44.4 Core and Builtins
...........................

   - bpo-43901(1): Change class and module objects to lazy-create empty
     annotations dicts on demand.  The annotations dicts are stored in
     the object’s __dict__ for backwards compatibility.

   - bpo-43892(2): Match patterns now use new dedicated AST nodes
     (‘MatchValue’, ‘MatchSingleton’, ‘MatchSequence’, ‘MatchStar’,
     ‘MatchMapping’, ‘MatchClass’) rather than reusing expression AST
     nodes.  ‘MatchAs’ and ‘MatchOr’ are now defined as pattern nodes
     rather than as expression nodes.  Patch by Nick Coghlan.

   - bpo-42725(3): Usage of ‘await’/‘yield’/‘yield from’ and named
     expressions within an annotation is now forbidden when PEP 563 is
     activated.

   - bpo-43754(4): When performing structural pattern matching ( PEP
     634(5)), captured names are now left unbound until the 'entire'
     pattern has matched successfully.

   - bpo-42737(6): Annotations for complex targets (everything beside
     simple names) no longer cause any runtime effects with ‘from
     __future__ import annotations’.

   - bpo-43914(7): *note SyntaxError: 18d. exceptions raised by the
     interpreter will highlight the full error range of the expression
     that constitutes the syntax error itself, instead of just where the
     problem is detected.  Patch by Pablo Galindo.

   - bpo-38605(8): Revert making ‘from __future__ import annotations’
     the default.  This follows the Steering Council decision to
     postpone PEP 563 changes to at least Python 3.11.  See the original
     email for more information regarding the decision:
     ‘https://mail.python.org/archives/list/python-dev@python.org/thread/CLVXXPQ2T2LQ5MP2Y53VVQFCXYWQJHKZ/’.
     Patch by Pablo Galindo.

   - bpo-43475(9): Hashes of NaN values now depend on object identity.
     Formerly, they always hashed to 0 even though NaN values are not
     equal to one another.  Having the same hash for unequal values
     caused pile-ups in hash tables.

   - bpo-43859(10): Improve the error message for *note
     IndentationError: 7ac. exceptions.  Patch by Pablo Galindo

   - bpo-41323(11): Constant tuple folding in bytecode optimizer now
     reuses tuple in constant table.

   - bpo-43846(12): Data stack usage is much reduced for large literal
     and call expressions.

   - bpo-38530(13): When printing *note NameError: 442. raised by the
     interpreter, ‘PyErr_Display()’ will offer suggestions of similar
     variable names in the function that the exception was raised from.
     Patch by Pablo Galindo

   - bpo-43823(14): Improve syntax errors for invalid dictionary
     literals.  Patch by Pablo Galindo.

   - bpo-43822(15): Improve syntax errors in the parser for missing
     commas between expressions.  Patch by Pablo Galindo.

   - bpo-43798(16): *note ast.alias: 1a1b. nodes now include source
     location metadata attributes e.g.  lineno, col_offset.

   - bpo-43797(17): Improve ‘SyntaxError’ error messages for invalid
     comparisons.  Patch by Pablo Galindo.

   - bpo-43760(18): Move the flag for checking whether tracing is
     enabled to the C stack, from the heap.  Should speed up dispatch in
     the interpreter.

   - bpo-43682(19): Static methods (*note @staticmethod: 419.) and class
     methods (*note @classmethod: 166.) now inherit the method
     attributes (‘__module__’, ‘__name__’, ‘__qualname__’, ‘__doc__’,
     ‘__annotations__’) and have a new ‘__wrapped__’ attribute.  Patch
     by Victor Stinner.

   - bpo-43751(20): Fixed a bug where ‘anext(ait, default)’ would
     erroneously return None.

   - bpo-42128(21): *note __match_args__: 1a1c. is no longer allowed to
     be a list.

   - bpo-43683(22): Add GEN_START opcode.  Marks start of generator,
     including async, or coroutine and handles sending values to a newly
     created generator or coroutine.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43901

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43892

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42725

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43754

   (5) https://peps.python.org/pep-0634/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42737

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43914

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38605

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43475

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43859

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41323

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43846

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38530

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43823

   (15) https://bugs.python.org/issue?@action=redirect&bpo=43822

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43798

   (17) https://bugs.python.org/issue?@action=redirect&bpo=43797

   (18) https://bugs.python.org/issue?@action=redirect&bpo=43760

   (19) https://bugs.python.org/issue?@action=redirect&bpo=43682

   (20) https://bugs.python.org/issue?@action=redirect&bpo=43751

   (21) https://bugs.python.org/issue?@action=redirect&bpo=42128

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43683


File: python.info,  Node: Library<94>,  Next: Core and Builtins<93>,  Prev: Core and Builtins<92>,  Up: Python 3 10 0 beta 1

1.23.44.5 Library
.................

   - bpo-43105(1): Importlib now resolves relative paths when creating
     module spec objects from file locations.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43105


File: python.info,  Node: Core and Builtins<93>,  Next: Library<95>,  Prev: Library<94>,  Up: Python 3 10 0 beta 1

1.23.44.6 Core and Builtins
...........................

   - bpo-43682(1): Static methods (*note @staticmethod: 419.) are now
     callable as regular functions.  Patch by Victor Stinner.

   - bpo-42609(2): Prevented crashes in the AST validator and optimizer
     when compiling some absurdly long expressions like ‘"+0"*1000000’.
     *note RecursionError: d96. is now raised instead.

   - bpo-38530(3): When printing *note AttributeError: 34e,
     ‘PyErr_Display()’ will offer suggestions of similar attribute names
     in the object that the exception was raised from.  Patch by Pablo
     Galindo

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43682

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42609

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38530


File: python.info,  Node: Library<95>,  Next: Documentation<35>,  Prev: Core and Builtins<93>,  Up: Python 3 10 0 beta 1

1.23.44.7 Library
.................

   - bpo-44015(1): In @dataclass(), raise a TypeError if KW_ONLY is
     specified more than once.

   - bpo-25478(2): Added a 'total()' method to collections.Counter() to
     compute the sum of the counts.

   - bpo-43733(3): Change *note netrc.netrc: 1a20. to use UTF-8 encoding
     before using locale encoding.

   - bpo-43979(4): Removed an unnecessary list comprehension before
     looping from *note urllib.parse.parse_qsl(): 279.  Patch by
     Christoph Zwerschke and Donghee Na.

   - bpo-43993(5): Update bundled pip to 21.1.1.

   - bpo-43957(6): [Enum] Deprecate ‘TypeError’ when non-member is used
     in a containment check; In 3.12 ‘True’ or ‘False’ will be returned
     instead, and containment will return ‘True’ if the value is either
     a member of that enum or one of its members’ value.

   - bpo-42904(7): For backwards compatibility with previous minor
     versions of Python, if *note typing.get_type_hints(): 6b4. receives
     no namespace dictionary arguments, ‘typing.get_type_hints()’ will
     search through the global then local namespaces during evaluation
     of stringized type annotations (string forward references) inside a
     class.

   - bpo-43945(8): [Enum] Deprecate non-standard mixin format()
     behavior: in 3.12 the enum member, not the member’s value, will be
     used for format() calls.

   - bpo-41139(9): Deprecate undocumented ‘cgi.log()’ API.

   - bpo-43937(10): Fixed the *note turtle: 101. module working with
     non-default root window.

   - bpo-43930(11): Update bundled pip to 21.1 and setuptools to 56.0.0

   - bpo-43907(12): Fix a bug in the pure-Python pickle implementation
     when using protocol 5, where bytearray instances that occur several
     time in the pickled object graph would incorrectly unpickle into
     repeated copies of the bytearray object.

   - bpo-43926(13): In ‘importlib.metadata’, provide a uniform interface
     to ‘Description’, allow for any field to be encoded with multiline
     values, remove continuation lines from multiline values, and add a
     ‘.json’ property for easy access to the PEP 566 JSON-compatible
     form.  Sync with ‘importlib_metadata 4.0’.

   - bpo-43920(14): OpenSSL 3.0.0: *note load_verify_locations(): f22.
     now returns a consistent error message when cadata contains no
     valid certificate.

   - bpo-43607(15): *note urllib: 108. can now convert Windows paths
     with ‘\\?\’ prefixes into URL paths.

   - bpo-43817(16): Add *note inspect.get_annotations(): 819, which
     safely computes the annotations defined on an object.  It works
     around the quirks of accessing the annotations from various types
     of objects, and makes very few assumptions about the object passed
     in.  ‘inspect.get_annotations()’ can also correctly un-stringize
     stringized annotations.

     *note inspect.signature(): 73b, ‘inspect.from_callable()’, and
     ‘inspect.from_function()’ now call *note inspect.get_annotations():
     819. to retrieve annotations.  This means ‘inspect.signature()’ and
     ‘inspect.from_callable()’ can now un-stringize stringized
     annotations, too.

   - bpo-43284(17): platform.win32_ver derives the windows version from
     sys.getwindowsversion().platform_version which in turn derives the
     version from kernel32.dll (which can be of a different version than
     Windows itself).  Therefore change the platform.win32_ver to
     determine the version using the platform module’s _syscmd_ver
     private function to return an accurate version.

   - bpo-42854(18): The *note ssl: d0. module now uses ‘SSL_read_ex’ and
     ‘SSL_write_ex’ internally.  The functions support reading and
     writing of data larger than 2 GB. Writing zero-length data no
     longer fails with a protocol violation error.

   - bpo-42333(19): Port ‘_ssl’ extension module to multiphase
     initialization.

   - bpo-43880(20): *note ssl: d0. now raises DeprecationWarning for
     OP_NO_SSL/TLS* options, old TLS versions, old protocols, and other
     features that have been deprecated since Python 3.6, 3.7, or
     OpenSSL 1.1.0.

   - bpo-41559(21): PEP 612(22) is now implemented purely in Python;
     builtin ‘types.GenericAlias’ objects no longer include
     ‘typing.ParamSpec’ in ‘__parameters__’ (with the exception of
     ‘collections.abc.Callable’‘s ‘GenericAlias’).  This means
     previously invalid uses of ‘ParamSpec’ (such as ‘list[P]’) which
     worked in earlier versions of Python 3.10 alpha, will now raise
     ‘TypeError’ during substitution.

   - bpo-43867(23): The *note multiprocessing: 94. ‘Server’ class now
     explicitly catches *note SystemExit: d69. and closes the client
     connection in this case.  It happens when the
     ‘Server.serve_client()’ method reaches the end of file (EOF).

   - bpo-40443(24): Remove unused imports: pyclbr no longer uses copy,
     and typing no longer uses ast.  Patch by Victor Stinner.

   - bpo-43820(25): Remove an unneeded copy of the namespace passed to
     dataclasses.make_dataclass().

   - bpo-43787(26): Add ‘__iter__()’ method to *note bz2.BZ2File: 86d,
     *note gzip.GzipFile: 41d, and *note lzma.LZMAFile: 1047.  It makes
     iterating them about 2x faster.  Patch by Inada Naoki.

   - bpo-43680(27): Deprecate io.OpenWrapper and _pyio.OpenWrapper: use
     io.open and _pyio.open instead.  Until Python 3.9, _pyio.open was
     not a static method and builtins.open was set to OpenWrapper to not
     become a bound method when set to a class variable.  _io.open is a
     built-in function whereas _pyio.open is a Python function.  In
     Python 3.10, _pyio.open() is now a static method, and
     builtins.open() is now io.open().

   - bpo-43680(28): The Python ‘_pyio.open()’ function becomes a static
     method to behave as *note io.open(): 520. built-in function: don’t
     become a bound method when stored as a class variable.  It becomes
     possible since static methods are now callable in Python 3.10.
     Moreover, ‘_pyio.OpenWrapper()’ becomes a simple alias to
     ‘_pyio.open()’.  Patch by Victor Stinner.

   - bpo-41515(29): Fix *note KeyError: 345. raised in *note
     typing.get_type_hints(): 6b4. due to synthetic modules that don’t
     appear in ‘sys.modules’.

   - bpo-43776(30): When *note subprocess.Popen: 199. args are provided
     as a string or as *note pathlib.Path: 229, the Popen instance repr
     now shows the right thing.

   - bpo-42248(31): [Enum] ensure exceptions raised in ‘_missing__’ are
     released

   - bpo-43744(32): fix issue with enum member name matching the start
     of a private variable name

   - bpo-43772(33): Fixed the return value of ‘TypeVar.__ror__’.  Patch
     by Jelle Zijlstra.

   - bpo-43764(34): Add match_args parameter to @dataclass decorator to
     allow suppression of __match_args__ generation.

   - bpo-43799(35): OpenSSL 3.0.0: define ‘OPENSSL_API_COMPAT’ 1.1.1 to
     suppress deprecation warnings.  Python requires OpenSSL 1.1.1 APIs.

   - bpo-43478(36): Mocks can no longer be used as the specs for other
     Mocks.  As a result, an already-mocked object cannot have an
     attribute mocked using ‘autospec=True’ or be the subject of a
     ‘create_autospec(...)’ call.  This can uncover bugs in tests since
     these Mock-derived Mocks will always pass certain tests (e.g.
     *note isinstance(): 445.) and builtin assert functions (e.g.
     assert_called_once_with) will unconditionally pass.

   - bpo-43794(37): Add *note ssl.OP_IGNORE_UNEXPECTED_EOF: 83d.
     constants (OpenSSL 3.0.0)

   - bpo-43785(38): Improve ‘bz2.BZ2File’ performance by removing the
     RLock from BZ2File.  This makes BZ2File thread unsafe in the face
     of multiple simultaneous readers or writers, just like its
     equivalent classes in *note gzip: 67. and *note lzma: 8a. have
     always been.  Patch by Inada Naoki.

   - bpo-43789(39): OpenSSL 3.0.0: Don’t call the password callback
     function a second time when first call has signaled an error
     condition.

   - bpo-43788(40): The header files for *note ssl: d0. error codes are
     now OpenSSL version-specific.  Exceptions will now show correct
     reason and library codes.  The ‘make_ssl_data.py’ script has been
     rewritten to use OpenSSL’s text file with error codes.

   - bpo-43766(41): Implement PEP 647(42) in the *note typing: 104.
     module by adding ‘TypeGuard’.

   - bpo-25264(43): *note os.path.realpath(): 225. now accepts a
     'strict' keyword-only argument.  When set to ‘True’, *note OSError:
     41a. is raised if a path doesn’t exist or a symlink loop is
     encountered.

   - bpo-43780(44): In ‘importlib.metadata’, incorporate changes from
     importlib_metadata 3.10: Add mtime-based caching during
     distribution discovery.  Flagged use of dict result from
     ‘entry_points()’ as deprecated.

   - gh-47383(45): The ‘P.args’ and ‘P.kwargs’ attributes of *note
     typing.ParamSpec: 15e. are now instances of the new classes *note
     typing.ParamSpecArgs: 7ca. and *note typing.ParamSpecKwargs: 7cb,
     which enables a more useful ‘repr()’.  Patch by Jelle Zijlstra.

   - bpo-43731(46): Add an ‘encoding’ parameter ‘logging.fileConfig()’.

   - bpo-43712(47): Add ‘encoding’ and ‘errors’ parameters to *note
     fileinput.input(): 805. and *note fileinput.FileInput: 73a.

   - bpo-38659(48): A ‘simple_enum’ decorator is added to the ‘enum’
     module to convert a normal class into an Enum.  ‘test_simple_enum’
     added to test simple enums against a corresponding normal Enum.
     Standard library modules updated to use ‘simple_enum’.

   - bpo-43764(49): Fix an issue where *note __match_args__: 1a1c.
     generation could fail for some *note dataclasses: 2f.

   - bpo-43752(50): Fix *note sqlite3: cf. regression for zero-sized
     blobs with converters, where ‘b""’ was returned instead of ‘None’.
     The regression was introduced by PR 24723.  Patch by Erlend E.
     Aasland.

   - bpo-43655(51): *note tkinter: f0. dialog windows are now recognized
     as dialogs by window managers on macOS and X Window.

   - bpo-43723(52): The following ‘threading’ methods are now deprecated
     and should be replaced:

        - ‘currentThread’ => *note threading.current_thread(): 309.

        - ‘activeCount’ => *note threading.active_count(): 30a.

        - ‘Condition.notifyAll’ => *note
          threading.Condition.notify_all(): 303.

        - ‘Event.isSet’ => *note threading.Event.is_set(): 304.

        - ‘Thread.setName’ => *note threading.Thread.name: 308.

        - ‘thread.getName’ => *note threading.Thread.name: 308.

        - ‘Thread.isDaemon’ => *note threading.Thread.daemon: 306.

        - ‘Thread.setDaemon’ => *note threading.Thread.daemon: 306.

     Patch by Jelle Zijlstra.

   - bpo-2135(53): Deprecate find_module() and find_loader()
     implementations in importlib and zipimport.

   - bpo-43534(54): *note turtle.textinput(): 1a21. and *note
     turtle.numinput(): 1a22. create now a transient window working on
     behalf of the canvas window.

   - bpo-43532(55): Add the ability to specify keyword-only fields to
     dataclasses.  These fields will become keyword-only arguments to
     the generated __init__.

   - bpo-43522(56): Fix problem with *note hostname_checks_common_name:
     b9b.  OpenSSL does not copy hostflags from 'struct SSL_CTX' to
     'struct SSL'.

   - bpo-8978(57): Improve error message for *note tarfile.open(): eab.
     when *note lzma: 8a. / *note bz2: 13. are unavailable.  Patch by
     Anthony Sottile.

   - bpo-42967(58): Allow *note bytes: 1c2. ‘separator’ argument in
     ‘urllib.parse.parse_qs’ and ‘urllib.parse.parse_qsl’ when parsing
     *note str: 44f. query strings.  Previously, this raised a
     ‘TypeError’.

   - bpo-43296(59): Improve *note sqlite3: cf. error handling:
     ‘sqlite3_value_blob()’ errors that set ‘SQLITE_NOMEM’ now raise
     *note MemoryError: 15ab.  Patch by Erlend E. Aasland.

   - bpo-43312(60): New functions *note
     sysconfig.get_preferred_scheme(): 693. and *note
     sysconfig.get_default_scheme(): 195a. are added to query a platform
     for its preferred “user”, “home”, and “prefix” (default) scheme
     names.

   - bpo-43265(61): Improve *note sqlite3.Connection.backup(): b98.
     error handling.  The error message for non-existent target database
     names is now ‘unknown database <database name>’ instead of ‘SQL
     logic error’.  Patch by Erlend E. Aasland.

   - bpo-41282(62): Install schemes in ‘distutils.command.install’ are
     now loaded from *note sysconfig: db.

   - bpo-41282(63): ‘distutils.sysconfig’ has been merged to *note
     sysconfig: db.

   - bpo-43176(64): Fixed processing of a dataclass that inherits from a
     frozen dataclass with no fields.  It is now correctly detected as
     an error.

   - bpo-43080(65): *note pprint: ae. now has support for *note
     dataclasses.dataclass: 1cb.  Patch by Lewis Gaul.

   - bpo-39950(66): Add ‘pathlib.Path.hardlink_to()’ method that
     supersedes ‘link_to()’.  The new method has the same argument order
     as ‘symlink_to()’.

   - bpo-42904(67): *note typing.get_type_hints(): 6b4. now checks the
     local namespace of a class when evaluating PEP 563(68) annotations
     inside said class.

   - bpo-42269(69): Add ‘slots’ parameter to ‘dataclasses.dataclass’
     decorator to automatically generate ‘__slots__’ for class.  Patch
     provided by Yurii Karabas.

   - bpo-39529(70): Deprecated use of *note asyncio.get_event_loop():
     2c2. without running event loop.  Emit deprecation warning for
     *note asyncio: a. functions which implicitly create a *note Future:
     bec. or *note Task: 1be. objects if there is no running event loop
     and no explicit 'loop' argument is passed: *note ensure_future():
     c98, *note wrap_future(): 1a23, *note gather(): 600, *note
     shield(): a7f, *note as_completed(): 1aa. and constructors of
     ‘Future’, ‘Task’, *note StreamReader: 15b6, ‘StreamReaderProtocol’.

   - bpo-18369(71): Certificate and PrivateKey classes were added to the
     ssl module.  Certificates and keys can now be loaded from memory
     buffer, too.

   - bpo-41486(72): Use a new output buffer management code for *note
     bz2: 13. / *note lzma: 8a. / *note zlib: 133. modules, and add
     ‘.readall()’ function to ‘_compression.DecompressReader’ class.
     These bring some performance improvements.  Patch by Ma Lin.

   - bpo-31870(73): The *note ssl.get_server_certificate(): 842.
     function now has a 'timeout' parameter.

   - bpo-41735(74): Fix thread locks in zlib module may go wrong in rare
     case.  Patch by Ma Lin.

   - bpo-36470(75): Fix dataclasses with ‘InitVar’s and *note replace():
     1809.  Patch by Claudiu Popa.

   - bpo-40849(76): Expose X509_V_FLAG_PARTIAL_CHAIN ssl flag

   - bpo-35114(77): *note ssl.RAND_status(): 1a24. now returns a boolean
     value (as documented) instead of ‘1’ or ‘0’.

   - bpo-39906(78): *note pathlib.Path.stat(): 829. and *note chmod():
     82a. now accept a 'follow_symlinks' keyword-only argument for
     consistency with corresponding functions in the *note os: a1.
     module.

   - bpo-39899(79): *note os.path.expanduser(): a21. now refuses to
     guess Windows home directories if the basename of current user’s
     home directory does not match their username.

     *note pathlib.Path.expanduser(): e75. and *note home(): e76. now
     consistently raise *note RuntimeError: 195. exception when a home
     directory cannot be resolved.  Previously a *note KeyError: 345.
     exception could be raised on Windows when the ‘"USERNAME"’
     environment variable was unset.

   - bpo-36076(80): Added SNI support to *note
     ssl.get_server_certificate(): 842.

   - bpo-38490(81): Covariance, Pearson’s correlation, and simple linear
     regression functionality was added to statistics module.  Patch by
     Tymoteusz Wołodźko.

   - bpo-33731(82): Provide a locale.localize() function, which converts
     a normalized number string into a locale format.

   - bpo-32745(83): Fix a regression in the handling of ctypes’ *note
     ctypes.c_wchar_p: 17f7. type: embedded null characters would cause
     a *note ValueError: 202. to be raised.  Patch by Zackery Spytz.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=44015

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25478

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43733

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43979

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43993

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43957

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42904

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43945

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41139

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43937

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43930

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43907

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43926

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43920

   (15) https://bugs.python.org/issue?@action=redirect&bpo=43607

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43817

   (17) https://bugs.python.org/issue?@action=redirect&bpo=43284

   (18) https://bugs.python.org/issue?@action=redirect&bpo=42854

   (19) https://bugs.python.org/issue?@action=redirect&bpo=42333

   (20) https://bugs.python.org/issue?@action=redirect&bpo=43880

   (21) https://bugs.python.org/issue?@action=redirect&bpo=41559

   (22) https://peps.python.org/pep-0612/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=43867

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40443

   (25) https://bugs.python.org/issue?@action=redirect&bpo=43820

   (26) https://bugs.python.org/issue?@action=redirect&bpo=43787

   (27) https://bugs.python.org/issue?@action=redirect&bpo=43680

   (28) https://bugs.python.org/issue?@action=redirect&bpo=43680

   (29) https://bugs.python.org/issue?@action=redirect&bpo=41515

   (30) https://bugs.python.org/issue?@action=redirect&bpo=43776

   (31) https://bugs.python.org/issue?@action=redirect&bpo=42248

   (32) https://bugs.python.org/issue?@action=redirect&bpo=43744

   (33) https://bugs.python.org/issue?@action=redirect&bpo=43772

   (34) https://bugs.python.org/issue?@action=redirect&bpo=43764

   (35) https://bugs.python.org/issue?@action=redirect&bpo=43799

   (36) https://bugs.python.org/issue?@action=redirect&bpo=43478

   (37) https://bugs.python.org/issue?@action=redirect&bpo=43794

   (38) https://bugs.python.org/issue?@action=redirect&bpo=43785

   (39) https://bugs.python.org/issue?@action=redirect&bpo=43789

   (40) https://bugs.python.org/issue?@action=redirect&bpo=43788

   (41) https://bugs.python.org/issue?@action=redirect&bpo=43766

   (42) https://peps.python.org/pep-0647/

   (43) https://bugs.python.org/issue?@action=redirect&bpo=25264

   (44) https://bugs.python.org/issue?@action=redirect&bpo=43780

   (45) https://github.com/python/cpython/issues/47383

   (46) https://bugs.python.org/issue?@action=redirect&bpo=43731

   (47) https://bugs.python.org/issue?@action=redirect&bpo=43712

   (48) https://bugs.python.org/issue?@action=redirect&bpo=38659

   (49) https://bugs.python.org/issue?@action=redirect&bpo=43764

   (50) https://bugs.python.org/issue?@action=redirect&bpo=43752

   (51) https://bugs.python.org/issue?@action=redirect&bpo=43655

   (52) https://bugs.python.org/issue?@action=redirect&bpo=43723

   (53) https://bugs.python.org/issue?@action=redirect&bpo=2135

   (54) https://bugs.python.org/issue?@action=redirect&bpo=43534

   (55) https://bugs.python.org/issue?@action=redirect&bpo=43532

   (56) https://bugs.python.org/issue?@action=redirect&bpo=43522

   (57) https://bugs.python.org/issue?@action=redirect&bpo=8978

   (58) https://bugs.python.org/issue?@action=redirect&bpo=42967

   (59) https://bugs.python.org/issue?@action=redirect&bpo=43296

   (60) https://bugs.python.org/issue?@action=redirect&bpo=43312

   (61) https://bugs.python.org/issue?@action=redirect&bpo=43265

   (62) https://bugs.python.org/issue?@action=redirect&bpo=41282

   (63) https://bugs.python.org/issue?@action=redirect&bpo=41282

   (64) https://bugs.python.org/issue?@action=redirect&bpo=43176

   (65) https://bugs.python.org/issue?@action=redirect&bpo=43080

   (66) https://bugs.python.org/issue?@action=redirect&bpo=39950

   (67) https://bugs.python.org/issue?@action=redirect&bpo=42904

   (68) https://peps.python.org/pep-0563/

   (69) https://bugs.python.org/issue?@action=redirect&bpo=42269

   (70) https://bugs.python.org/issue?@action=redirect&bpo=39529

   (71) https://bugs.python.org/issue?@action=redirect&bpo=18369

   (72) https://bugs.python.org/issue?@action=redirect&bpo=41486

   (73) https://bugs.python.org/issue?@action=redirect&bpo=31870

   (74) https://bugs.python.org/issue?@action=redirect&bpo=41735

   (75) https://bugs.python.org/issue?@action=redirect&bpo=36470

   (76) https://bugs.python.org/issue?@action=redirect&bpo=40849

   (77) https://bugs.python.org/issue?@action=redirect&bpo=35114

   (78) https://bugs.python.org/issue?@action=redirect&bpo=39906

   (79) https://bugs.python.org/issue?@action=redirect&bpo=39899

   (80) https://bugs.python.org/issue?@action=redirect&bpo=36076

   (81) https://bugs.python.org/issue?@action=redirect&bpo=38490

   (82) https://bugs.python.org/issue?@action=redirect&bpo=33731

   (83) https://bugs.python.org/issue?@action=redirect&bpo=32745


File: python.info,  Node: Documentation<35>,  Next: Tests<38>,  Prev: Library<95>,  Up: Python 3 10 0 beta 1

1.23.44.8 Documentation
.......................

   - bpo-43987(1): Add “Annotations Best Practices” document as a new
     HOWTO.

   - bpo-43977(2): Document the new *note Py_TPFLAGS_MAPPING: 19fe. and
     *note Py_TPFLAGS_SEQUENCE: 19ff. type flags.

   - bpo-43959(3): The documentation on the PyContextVar C-API was
     clarified.

   - bpo-43938(4): Update dataclasses documentation to express that
     FrozenInstanceError is derived from AttributeError.

   - bpo-43778(5): Fix the Sphinx glossary_search extension: create the
     _static/ sub-directory if it doesn’t exist.

   - bpo-43755(6): Update documentation to reflect that unparenthesized
     lambda expressions can no longer be the expression part in an ‘if’
     clause in comprehensions and generator expressions since Python
     3.9.

   - bpo-43739(7): Fixing the example code in
     Doc/extending/extending.rst to declare and initialize the pmodule
     variable to be of the right type.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43987

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43977

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43959

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43938

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43778

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43755

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43739


File: python.info,  Node: Tests<38>,  Next: Build<42>,  Prev: Documentation<35>,  Up: Python 3 10 0 beta 1

1.23.44.9 Tests
...............

   - bpo-43961(1): Fix test_logging.test_namer_rotator_inheritance() on
     Windows: use *note os.replace(): 1136. rather than *note
     os.rename(): 1135.  Patch by Victor Stinner.

   - bpo-43842(2): Fix a race condition in the SMTP test of
     test_logging.  Don’t close a file descriptor (socket) from a
     different thread while asyncore.loop() is polling the file
     descriptor.  Patch by Victor Stinner.

   - bpo-43843(3): ‘test.libregrtest’ now marks a test as ENV_CHANGED
     (altered the execution environment) if a thread raises an exception
     but does not catch it.  It sets a hook on *note
     threading.excepthook(): 851.  Use ‘--fail-env-changed’ option to
     mark the test as failed.  Patch by Victor Stinner.

   - bpo-43811(4): Tests multiple OpenSSL versions on GitHub Actions.
     Use ccache to speed up testing.

   - bpo-43791(5): OpenSSL 3.0.0: Disable testing of legacy protocols
     TLS 1.0 and 1.1.  Tests are failing with
     TLSV1_ALERT_INTERNAL_ERROR.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43961

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43842

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43843

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43811

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43791


File: python.info,  Node: Build<42>,  Next: Windows<36>,  Prev: Tests<38>,  Up: Python 3 10 0 beta 1

1.23.44.10 Build
................

   - bpo-43567(1): Improved generated code refresh
     (AST/tokens/opcodes/keywords) on Windows.

   - bpo-43669(2): Implement PEP 644(3).  Python now requires OpenSSL
     1.1.1 or newer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43567

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43669

   (3) https://peps.python.org/pep-0644/


File: python.info,  Node: Windows<36>,  Next: macOS<28>,  Prev: Build<42>,  Up: Python 3 10 0 beta 1

1.23.44.11 Windows
..................

   - bpo-35306(1): Adds additional arguments to *note os.startfile():
     1a29. function.

   - bpo-43538(2): Avoid raising errors from *note
     pathlib.Path.exists(): a23. when passed an invalid filename.

   - bpo-38822(3): Fixed *note os.stat(): 4a3. failing on inaccessible
     directories with a trailing slash, rather than falling back to the
     parent directory’s metadata.  This implicitly affected *note
     os.path.exists(): a1b. and *note os.path.isdir(): a1d.

   - bpo-26227(4): Fixed decoding of host names in *note
     socket.gethostbyaddr(): 1a2a. and *note socket.gethostbyname_ex():
     1a2b.

   - bpo-40432(5): Updated pegen regeneration script on Windows to find
     and use Python 3.8 or higher.  Prior to this, pegen regeneration
     already required 3.8 or higher, but the script may have used lower
     versions of Python.

   - bpo-43745(6): Actually updates Windows release to OpenSSL 1.1.1k.
     Earlier releases were mislabelled and actually included 1.1.1i
     again.

   - bpo-43652(7): Update Tcl and Tk to 8.6.11 in Windows installer.

   - bpo-43492(8): Upgrade Windows installer to use SQLite 3.35.5.

   - bpo-30555(9): Fix ‘WindowsConsoleIO’ errors in the presence of fd
     redirection.  Patch by Segev Finer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35306

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43538

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38822

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26227

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40432

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43745

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43652

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43492

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30555


File: python.info,  Node: macOS<28>,  Next: IDLE<24>,  Prev: Windows<36>,  Up: Python 3 10 0 beta 1

1.23.44.12 macOS
................

   - bpo-42119(1): Fix check for macOS SDK paths when building Python.
     Narrow search to match contents of SDKs, namely only files in
     ‘/System/Library’, ‘/System/IOSSupport’, and ‘/usr’ other than
     ‘/usr/local’.  Previously, anything under ‘/System’ was assumed to
     be in an SDK which causes problems with the new file system layout
     in 10.15+ where user file systems may appear to be mounted under
     ‘/System’.  Paths in ‘/Library’ were also incorrectly treated as
     SDK locations.

   - bpo-43568(2): Drop support for MACOSX_DEPLOYMENT_TARGET < 10.3

   - bpo-44009(3): Provide “python3.x-intel64” executable to allow
     reliably forcing macOS universal2 framework builds to run under
     Rosetta 2 Intel-64 emulation on Apple Silicon Macs.  This can be
     useful for testing or when universal2 wheels are not yet available.

   - bpo-43851(4): Build SQLite with ‘SQLITE_OMIT_AUTOINIT’ on macOS.
     Patch by Erlend E. Aasland.

   - bpo-43492(5): Update macOS installer to use SQLite 3.35.4.

   - bpo-42235(6): ‘Mac/BuildScript/build-installer.py’ will now use
     “–enable-optimizations” and ‘--with-lto’ when building on macOS
     10.15 or later.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42119

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43568

   (3) https://bugs.python.org/issue?@action=redirect&bpo=44009

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43851

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43492

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42235


File: python.info,  Node: IDLE<24>,  Next: C API<37>,  Prev: macOS<28>,  Up: Python 3 10 0 beta 1

1.23.44.13 IDLE
...............

   - bpo-37903(1): Add mouse actions to the shell sidebar.  Left click
     and optional drag selects one or more lines, as with the editor
     line number sidebar.  Right click after selecting raises a context
     menu with ‘copy with prompts’.  This zips together prompts from the
     sidebar with lines from the selected text.

   - bpo-43981(2): Fix reference leak in test_sidebar and test_squeezer.
     Patches by Terry Jan Reedy and Pablo Galindo

   - bpo-37892(3): Indent IDLE Shell input with spaces instead of tabs

   - bpo-43655(4): IDLE dialog windows are now recognized as dialogs by
     window managers on macOS and X Window.

   - bpo-37903(5): IDLE’s shell now shows prompts in a separate
     side-bar.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37903

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43981

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37892

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43655

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37903


File: python.info,  Node: C API<37>,  Prev: IDLE<24>,  Up: Python 3 10 0 beta 1

1.23.44.14 C API
................

   - bpo-43916(1): Add a new *note Py_TPFLAGS_DISALLOW_INSTANTIATION:
     585. type flag to disallow creating type instances.  Patch by
     Victor Stinner.

   - bpo-43774(2): Remove the now unused ‘PYMALLOC_DEBUG’ macro.  Debug
     hooks on memory allocators are now installed by default if Python
     is built in debug mode (if ‘Py_DEBUG’ macro is defined).  Moreover,
     they can now be used on Python build in release mode (ex: using
     ‘PYTHONMALLOC=debug’ environment variable).

   - bpo-43962(3): _PyInterpreterState_IDIncref() now calls
     _PyInterpreterState_IDInitref() and always increments id_refcount.
     Previously, calling _xxsubinterpreters.get_current() could create
     an id_refcount inconsistency when a
     _xxsubinterpreters.InterpreterID object was deallocated.  Patch by
     Victor Stinner.

   - bpo-28254(4): Add new C-API functions to control the state of the
     garbage collector: *note PyGC_Enable(): 8ab, *note PyGC_Disable():
     8ac, *note PyGC_IsEnabled(): 8ad, corresponding to the functions in
     the *note gc: 60. module.

   - bpo-43908(5): Introduce *note Py_TPFLAGS_IMMUTABLETYPE: 3c5. flag
     for immutable type objects, and modify *note PyType_Ready(): 77f.
     to set it for static types.  Patch by Erlend E. Aasland.

   - bpo-43795(6): *note PyMem_Calloc(): ee1. is now available in the
     limited C API (‘Py_LIMITED_API’).

   - bpo-43868(7): *note PyOS_ReadlineFunctionPointer(): 589. is no
     longer exported by limited C API headers and by ‘python3.dll’ on
     Windows.  Like any function that takes ‘FILE*’, it is not part of
     the stable ABI.

   - bpo-43795(8): Stable ABI and limited API definitions are generated
     from a central manifest ( PEP 652(9)).

   - bpo-43753(10): Add the *note Py_Is(x, y): 8a7. function to test if
     the 'x' object is the 'y' object, the same as ‘x is y’ in Python.
     Add also the *note Py_IsNone(): 8a8, *note Py_IsTrue(): 8a9, *note
     Py_IsFalse(): 8aa. functions to test if an object is, respectively,
     the ‘None’ singleton, the ‘True’ singleton or the ‘False’
     singleton.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43916

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43774

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43962

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28254

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43908

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43795

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43868

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43795

   (9) https://peps.python.org/pep-0652/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43753


File: python.info,  Node: Python 3 10 0 alpha 7,  Next: Python 3 10 0 alpha 6,  Prev: Python 3 10 0 beta 1,  Up: Changelog

1.23.45 Python 3.10.0 alpha 7
-----------------------------

'Release date: 2021-04-05'

* Menu:

* Security: Security<28>.
* Core and Builtins: Core and Builtins<94>.
* Library: Library<96>.
* Core and Builtins: Core and Builtins<95>.
* Library: Library<97>.
* Documentation: Documentation<36>.
* Tests: Tests<39>.
* Build: Build<43>.
* Windows: Windows<37>.
* IDLE: IDLE<25>.
* C API: C API<38>.


File: python.info,  Node: Security<28>,  Next: Core and Builtins<94>,  Up: Python 3 10 0 alpha 7

1.23.45.1 Security
..................

   - bpo-42988(1): CVE 2021-3426(2): Remove the ‘getfile’ feature of the
     *note pydoc: b5. module which could be abused to read arbitrary
     files on the disk (directory traversal vulnerability).  Moreover,
     even source code of Python modules can contain sensitive data like
     passwords.  Vulnerability reported by David Schwörer.

   - bpo-43285(3): *note ftplib: 5e. no longer trusts the IP address
     value returned from the server in response to the PASV command by
     default.  This prevents a malicious FTP server from using the
     response to probe IPv4 address and port combinations on the client
     network.

     Code that requires the former vulnerable behavior may set a
     ‘trust_server_pasv_ipv4_address’ attribute on their *note
     ftplib.FTP: 903. instances to ‘True’ to re-enable it.

   - bpo-43439(4): Add audit hooks for *note gc.get_objects(): 809,
     *note gc.get_referrers(): 80a. and *note gc.get_referents(): 80b.
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42988

   (2) https://www.cve.org/CVERecord?id=CVE-2021-3426

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43285

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43439


File: python.info,  Node: Core and Builtins<94>,  Next: Library<96>,  Prev: Security<28>,  Up: Python 3 10 0 alpha 7

1.23.45.2 Core and Builtins
...........................

   - bpo-27129(1): Update CPython bytecode magic number.

   - bpo-43672(2): Raise ImportWarning when calling find_loader().

   - bpo-43660(3): Fix crash that happens when replacing ‘sys.stderr’
     with a callable that can remove the object while an exception is
     being printed.  Patch by Pablo Galindo.

   - bpo-27129(4): The bytecode interpreter uses instruction, rather
     byte, offsets internally.  This reduces the number of EXTENDED_ARG
     instructions needed and streamlines instruction dispatch a bit.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27129

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43672

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43660

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27129


File: python.info,  Node: Library<96>,  Next: Core and Builtins<95>,  Prev: Core and Builtins<94>,  Up: Python 3 10 0 alpha 7

1.23.45.3 Library
.................

   - bpo-40645(1): Fix reference leak in the ‘_hashopenssl’ extension.
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40645


File: python.info,  Node: Core and Builtins<95>,  Next: Library<97>,  Prev: Library<96>,  Up: Python 3 10 0 alpha 7

1.23.45.4 Core and Builtins
...........................

   - bpo-42134(1): Calls to find_module() by the import system now raise
     ImportWarning.

   - bpo-41064(2): Improve the syntax error for invalid usage of double
     starred elements (‘**’) in f-strings.  Patch by Pablo Galindo.

   - bpo-43575(3): Speed up calls to ‘map()’ by using the PEP 590(4)
     ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-42137(5): The import system now prefers using ‘__spec__’ for
     ‘ModuleType.__repr__’ over ‘module_repr()’.

   - bpo-43452(6): Added micro-optimizations to ‘_PyType_Lookup()’ to
     improve cache lookup performance in the common case of cache hits.

   - bpo-43555(7): Report the column offset for *note SyntaxError: 18d.
     for invalid line continuation characters.  Patch by Pablo Galindo.

   - bpo-43517(8): Fix misdetection of circular imports when using ‘from
     pkg.mod import attr’, which caused false positives in non-trivial
     multi-threaded code.

   - bpo-43497(9): Emit SyntaxWarnings for assertions with tuple
     constants, this is a regression introduced in python3.7

   - bpo-39316(10): Tracing now has correct line numbers for attribute
     accesses when the attribute is on a different line from the object.
     Improves debugging and profiling for multi-line method chains.

   - bpo-35883(11): Python no longer fails at startup with a fatal error
     if a command line argument contains an invalid Unicode character.
     The *note Py_DecodeLocale(): be6. function now escapes byte
     sequences which would be decoded as Unicode characters outside the
     [U+0000; U+10ffff] range.

   - bpo-43410(12): Fix a bug that was causing the parser to crash when
     emitting syntax errors when reading input from stdin.  Patch by
     Pablo Galindo

   - bpo-43406(13): Fix a possible race condition where
     ‘PyErr_CheckSignals’ tries to execute a non-Python signal handler.

   - bpo-42128(14): Add ‘__match_args__’ to *note struct sequence
     objects: 1204.  Patch by Pablo Galindo.

   - bpo-43390(15): CPython now sets the ‘SA_ONSTACK’ flag in
     ‘PyOS_setsig’ for the VM’s default signal handlers.  This is
     friendlier to other in-process code that an extension module or
     embedding use could pull in (such as Golang’s cgo) where tiny
     thread stacks are the norm and ‘sigaltstack()’ has been used to
     provide for signal handlers.  This is a no-op change for the vast
     majority of processes that don’t use sigaltstack.

   - bpo-43287(16): Speed up calls to ‘filter()’ by using the PEP
     590(17) ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-37448(18): Add a radix tree based memory map to track in-use
     obmalloc arenas.  Use to replace the old implementation of
     address_in_range().  The radix tree approach makes it easy to
     increase pool sizes beyond the OS page size.  Boosting the pool and
     arena size allows obmalloc to handle a significantly higher
     percentage of requests from its ultra-fast paths.

     It also has the advantage of eliminating the memory unsanitary
     behavior of the previous address_in_range().  The old
     address_in_range() was marked with the annotations
     _Py_NO_SANITIZE_ADDRESS, _Py_NO_SANITIZE_THREAD, and
     _Py_NO_SANITIZE_MEMORY. Those annotations are no longer needed.

     To disable the radix tree map, set a preprocessor flag as follows:
     ‘-DWITH_PYMALLOC_RADIX_TREE=0’.

     Co-authored-by: Tim Peters <<tim.peters@gmail.com>>

   - bpo-29988(19): Only handle asynchronous exceptions and requests to
     drop the GIL when returning from a call or on the back edges of
     loops.  Makes sure that *note __exit__(): 1349. is always called in
     with statements, even for interrupts.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42134

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41064

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43575

   (4) https://peps.python.org/pep-0590/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42137

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43452

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43555

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43517

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43497

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39316

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35883

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43410

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43406

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42128

   (15) https://bugs.python.org/issue?@action=redirect&bpo=43390

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43287

   (17) https://peps.python.org/pep-0590/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37448

   (19) https://bugs.python.org/issue?@action=redirect&bpo=29988


File: python.info,  Node: Library<97>,  Next: Documentation<36>,  Prev: Core and Builtins<95>,  Up: Python 3 10 0 alpha 7

1.23.45.5 Library
.................

   - bpo-43720(1): Document various stdlib deprecations in imp, pkgutil,
     and importlib.util for removal in Python 3.12.

   - bpo-43433(2): *note xmlrpc.client.ServerProxy: a65. no longer
     ignores query and fragment in the URL of the server.

   - bpo-31956(3): The *note index(): 7e5. method of *note array.array:
     1a0. now has optional 'start' and 'stop' parameters.

   - bpo-40066(4): Enum: adjust ‘repr()’ to show only enum and member
     name (not value, nor angle brackets) and ‘str()’ to show only
     member name.  Update and improve documentation to match.

   - bpo-42136(5): Deprecate all module_repr() methods found in
     importlib as their use is being phased out by Python 3.12.

   - bpo-35930(6): Raising an exception raised in a “future” instance
     will create reference cycles.

   - bpo-41369(7): Finish updating the vendored libmpdec to version
     2.5.1.  Patch by Stefan Krah.

   - bpo-43422(8): Revert the _decimal C API which was added in
     bpo-41324(9).

   - bpo-43577(10): Fix deadlock when using *note ssl.SSLContext: 294.
     debug callback with *note ssl.SSLContext.sni_callback(): 1a35.

   - bpo-43571(11): It’s now possible to create MPTCP sockets with
     IPPROTO_MPTCP

   - bpo-43542(12): ‘image/heic’ and ‘image/heif’ were added to *note
     mimetypes: 8f.

   - bpo-40645(13): The *note hmac: 6a. module now uses OpenSSL’s HMAC
     implementation when digestmod argument is a hash name or builtin
     hash function.

   - bpo-43510(14): Implement PEP 597(15): Add ‘EncodingWarning’
     warning, ‘-X warn_default_encoding’ option, *note
     PYTHONWARNDEFAULTENCODING: 7c0. environment variable and
     ‘encoding="locale"’ argument value.

   - bpo-43521(16): ‘ast.unparse’ can now render NaNs and empty sets.

   - bpo-42914(17): *note pprint.pprint(): 82e. gains a new boolean
     ‘underscore_numbers’ optional argument to emit integers with
     thousands separated by an underscore character for improved
     readability (for example ‘1_000_000’ instead of ‘1000000’).

   - bpo-41361(18): *note rotate(): 1a36. calls are now slightly faster
     due to faster argument parsing.

   - bpo-43423(19): ‘subprocess.communicate()’ no longer raises an
     IndexError when there is an empty stdout or stderr IO buffer during
     a timeout on Windows.

   - bpo-27820(20): Fixed long-standing bug of smtplib.SMTP where doing
     AUTH LOGIN with initial_response_ok=False will fail.

     The cause is that SMTP.auth_login _always_ returns a password if
     provided with a challenge string, thus non-compliant with the
     standard for AUTH LOGIN.

     Also fixes bug with the test for smtpd.

   - bpo-43445(21): Add frozen modules to *note sys.stdlib_module_names:
     847.  For example, add ‘"_frozen_importlib"’ and
     ‘"_frozen_importlib_external"’ names.

   - bpo-43245(22): Add keyword arguments support to
     ‘ChainMap.new_child()’.

   - bpo-29982(23): Add optional parameter 'ignore_cleanup_errors' to
     *note tempfile.TemporaryDirectory(): 127a. and allow multiple
     ‘cleanup()’ attempts.  Contributed by C.A.M. Gerlach.

   - bpo-43428(24): Include changes from importlib_metadata 3.7(25):

     Performance enhancements to distribution discovery.

     ‘entry_points’ only returns unique distributions.

     Introduces new ‘EntryPoints’ object for containing a set of entry
     points with convenience methods for selecting entry points by group
     or name.  ‘entry_points’ now returns this object if selection
     parameters are supplied but continues to return a dict object for
     compatibility.  Users are encouraged to rely on the selection
     interface.  The dict object result is likely to be deprecated in
     the future.

     Added packages_distributions function to return a mapping of
     packages to the distributions that provide them.

   - bpo-43332(26): Improves the networking efficiency of *note
     http.client: 6f. when using a proxy via ‘set_tunnel()’.  Fewer
     small send calls are made during connection setup.

   - bpo-43420(27): Improve performance of *note fractions.Fraction:
     1e7. arithmetics for large components.  Contributed by Sergey B.
     Kirpichev.

   - bpo-43356(28): Allow passing a signal number to
     ‘_thread.interrupt_main()’.

   - bpo-43399(29): Fix ‘ElementTree.extend’ not working on iterators
     when using the Python implementation

   - bpo-43369(30): Improve *note sqlite3: cf. error handling: If
     ‘sqlite3_column_text()’ and ‘sqlite3_column_blob()’ set
     ‘SQLITE_NOMEM’, *note MemoryError: 15ab. is now raised.  Patch by
     Erlend E. Aasland.

   - bpo-43368(31): Fix a regression introduced in PR 24562, where an
     empty bytestring was fetched as ‘None’ instead of ‘b''’ in *note
     sqlite3: cf.  Patch by Mariusz Felisiak.

   - bpo-41282(32): Fixed stacklevel of ‘DeprecationWarning’ emitted
     from ‘import distutils’.

   - bpo-42129(33): ‘importlib.resources’ now honors namespace packages,
     merging resources from each location in the namespace as introduced
     in ‘importlib_resources’ 3.2 and including incidental changes
     through 5.0.3.

   - bpo-43295(34): *note datetime.datetime.strptime(): 1714. now raises
     ‘ValueError’ instead of ‘IndexError’ when matching ‘'z'’ with the
     ‘%z’ format specifier.

   - bpo-43125(35): Return empty string if base64mime.body_encode
     receive empty bytes

   - bpo-43084(36): *note curses.window.enclose(): 1a37. returns now
     ‘True’ or ‘False’ (as was documented) instead of ‘1’ or ‘0’.

   - bpo-42994(37): Add MIME types for opus, AAC, 3gpp and 3gpp2

   - bpo-14678(38): Add an invalidate_caches() method to the
     zipimport.zipimporter class to support
     importlib.invalidate_caches().  Patch by Desmond Cheong.

   - bpo-42782(39): Fail fast in *note shutil.move(): a6a. to avoid
     creating destination directories on failure.

   - bpo-40066(40): Enum’s ‘repr()’ and ‘str()’ have changed: ‘repr()’
     is now 'EnumClass.MemberName' and ‘str()’ is 'MemberName'.
     Additionally, stdlib Enum’s whose contents are available as module
     attributes, such as ‘RegexFlag.IGNORECASE’, have their ‘repr()’ as
     'module.name', e.g.  ‘re.IGNORECASE’.

   - bpo-26053(41): Fixed bug where the *note pdb: a5. interactive run
     command echoed the args from the shell command line, even if those
     have been overridden at the pdb prompt.

   - bpo-24160(42): Fixed bug where breakpoints did not persist across
     multiple debugger sessions in *note pdb: a5.’s interactive mode.

   - bpo-40701(43): When the *note tempfile.tempdir: 1a38. global
     variable is set to a value of type bytes, it is now handled
     consistently.  Previously exceptions could be raised from some
     tempfile APIs when the directory did not already exist in this
     situation.  Also ensures that the *note tempfile.gettempdir():
     1a39. and *note tempfile.gettempdirb(): 1a3a. functions 'always'
     return ‘str’ and ‘bytes’ respectively.

   - bpo-39342(44): Expose ‘X509_V_FLAG_ALLOW_PROXY_CERTS’ as *note
     VERIFY_ALLOW_PROXY_CERTS: 1a3b. to allow proxy certificate
     validation as explained in
     ‘https://docs.openssl.org/1.1.1/man7/proxy-certificates/’.

   - bpo-31861(45): Add builtins.aiter and builtins.anext.  Patch by
     Joshua Bronson (@jab), Daniel Pope (@lordmauve), and Justin Wang
     (@justin39).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43720

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43433

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31956

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40066

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42136

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35930

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41369

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43422

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41324

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43577

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43571

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43542

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40645

   (14) https://bugs.python.org/issue?@action=redirect&bpo=43510

   (15) https://peps.python.org/pep-0597/

   (16) https://bugs.python.org/issue?@action=redirect&bpo=43521

   (17) https://bugs.python.org/issue?@action=redirect&bpo=42914

   (18) https://bugs.python.org/issue?@action=redirect&bpo=41361

   (19) https://bugs.python.org/issue?@action=redirect&bpo=43423

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27820

   (21) https://bugs.python.org/issue?@action=redirect&bpo=43445

   (22) https://bugs.python.org/issue?@action=redirect&bpo=43245

   (23) https://bugs.python.org/issue?@action=redirect&bpo=29982

   (24) https://bugs.python.org/issue?@action=redirect&bpo=43428

   (25) 
https://importlib-metadata.readthedocs.io/en/latest/history.html#v3-7-0

   (26) https://bugs.python.org/issue?@action=redirect&bpo=43332

   (27) https://bugs.python.org/issue?@action=redirect&bpo=43420

   (28) https://bugs.python.org/issue?@action=redirect&bpo=43356

   (29) https://bugs.python.org/issue?@action=redirect&bpo=43399

   (30) https://bugs.python.org/issue?@action=redirect&bpo=43369

   (31) https://bugs.python.org/issue?@action=redirect&bpo=43368

   (32) https://bugs.python.org/issue?@action=redirect&bpo=41282

   (33) https://bugs.python.org/issue?@action=redirect&bpo=42129

   (34) https://bugs.python.org/issue?@action=redirect&bpo=43295

   (35) https://bugs.python.org/issue?@action=redirect&bpo=43125

   (36) https://bugs.python.org/issue?@action=redirect&bpo=43084

   (37) https://bugs.python.org/issue?@action=redirect&bpo=42994

   (38) https://bugs.python.org/issue?@action=redirect&bpo=14678

   (39) https://bugs.python.org/issue?@action=redirect&bpo=42782

   (40) https://bugs.python.org/issue?@action=redirect&bpo=40066

   (41) https://bugs.python.org/issue?@action=redirect&bpo=26053

   (42) https://bugs.python.org/issue?@action=redirect&bpo=24160

   (43) https://bugs.python.org/issue?@action=redirect&bpo=40701

   (44) https://bugs.python.org/issue?@action=redirect&bpo=39342

   (45) https://bugs.python.org/issue?@action=redirect&bpo=31861


File: python.info,  Node: Documentation<36>,  Next: Tests<39>,  Prev: Library<97>,  Up: Python 3 10 0 alpha 7

1.23.45.6 Documentation
.......................

   - bpo-43199(1): Answer “Why is there no goto?” in the Design and
     History FAQ.

   - bpo-43407(2): Clarified that a result from *note time.monotonic():
     253, *note time.perf_counter(): a97, *note time.process_time():
     a98, or *note time.thread_time(): 940. can be compared with the
     result from any following call to the same function - not just the
     next immediate call.

   - bpo-43354(3): Fix type documentation for ‘Fault.faultCode’; the
     type has to be ‘int’ instead of ‘str’.

   - bpo-41933(4): Clarified wording of s * n in the Common Sequence
     Operations

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43199

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43407

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43354

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41933


File: python.info,  Node: Tests<39>,  Next: Build<43>,  Prev: Documentation<36>,  Up: Python 3 10 0 alpha 7

1.23.45.7 Tests
...............

   - bpo-37945(1): Fix test_getsetlocale_issue1813() of test_locale:
     skip the test if ‘setlocale()’ fails.  Patch by Victor Stinner.

   - bpo-41561(2): Add workaround for Ubuntu’s custom OpenSSL security
     level policy.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37945

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41561


File: python.info,  Node: Build<43>,  Next: Windows<37>,  Prev: Tests<39>,  Up: Python 3 10 0 alpha 7

1.23.45.8 Build
...............

   - bpo-43179(1): Introduce and correctly use ALIGNOF_X in place of
     SIZEOF_X for alignment-related code in optimized string routines.
     Patch by Jessica Clarke.

   - bpo-43631(2): Update macOS, Windows, and CI to OpenSSL 1.1.1k.

   - bpo-43617(3): Improve configure.ac: Check for presence of
     autoconf-archive package and remove our copies of M4 macros.

   - bpo-43466(4): The ‘configure’ script now supports
     ‘--with-openssl-rpath’ option.

   - bpo-43372(5): Use ‘_freeze_importlib’ to generate code for the
     ‘__hello__’ module.  This approach ensures the code matches the
     interpreter version.  Previously, PYTHON_FOR_REGEN was used to
     generate the code, which might be wrong.  The marshal format for
     code objects has changed with bpo-42246(6), commit 877df851.
     Update the code and the expected code sizes in ctypes
     test_frozentable.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43179

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43631

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43617

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43466

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43372

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42246


File: python.info,  Node: Windows<37>,  Next: IDLE<25>,  Prev: Build<43>,  Up: Python 3 10 0 alpha 7

1.23.45.9 Windows
.................

   - bpo-43440(1): Build *note sqlite3: cf. with the ‘R*Tree’ module
     enabled.  Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43440


File: python.info,  Node: IDLE<25>,  Next: C API<38>,  Prev: Windows<37>,  Up: Python 3 10 0 alpha 7

1.23.45.10 IDLE
...............

   - bpo-42225(1): Document that IDLE can fail on Unix either from
     misconfigured IP masquerade rules or failure displaying complex
     colored (non-ascii) characters.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42225


File: python.info,  Node: C API<38>,  Prev: IDLE<25>,  Up: Python 3 10 0 alpha 7

1.23.45.11 C API
................

   - bpo-43688(1): The limited C API is now supported if Python is built
     in debug mode (if the ‘Py_DEBUG’ macro is defined).  In the limited
     C API, the *note Py_INCREF(): 571. and *note Py_DECREF(): 572.
     functions are now implemented as opaque function calls, rather than
     accessing directly the *note PyObject.ob_refcnt: 8a6. member, if
     Python is built in debug mode and the ‘Py_LIMITED_API’ macro
     targets Python 3.10 or newer.  It became possible to support the
     limited C API in debug mode because the *note PyObject: 33a.
     structure is the same in release and debug mode since Python 3.8
     (see bpo-36465(2)).

     The limited C API is still not supported in the ‘--with-trace-refs’
     special build (‘Py_TRACE_REFS’ macro).

     Patch by Victor Stinner.

   - bpo-43244(3): Remove the ‘pyarena.h’ header file with functions:

        * ‘PyArena_New()’

        * ‘PyArena_Free()’

        * ‘PyArena_Malloc()’

        * ‘PyArena_AddPyObject()’

     These functions were undocumented, excluded from the limited C API,
     and were only used internally by the compiler.  Patch by Victor
     Stinner.

   - bpo-43244(4): Remove the compiler and parser functions using
     ‘struct _mod’ type, because the public AST C API was removed:

        * ‘PyAST_Compile()’

        * ‘PyAST_CompileEx()’

        * ‘PyAST_CompileObject()’

        * ‘PyFuture_FromAST()’

        * ‘PyFuture_FromASTObject()’

        * ‘PyParser_ASTFromFile()’

        * ‘PyParser_ASTFromFileObject()’

        * ‘PyParser_ASTFromFilename()’

        * ‘PyParser_ASTFromString()’

        * ‘PyParser_ASTFromStringObject()’

     These functions were undocumented and excluded from the limited C
     API. Patch by Victor Stinner.

   - bpo-43244(5): Remove ‘ast.h’, ‘asdl.h’, and ‘Python-ast.h’ header
     files.  These functions were undocumented and excluded from the
     limited C API. Most names defined by these header files were not
     prefixed by ‘Py’ and so could create names conflicts.  For example,
     ‘Python-ast.h’ defined a ‘Yield’ macro which was conflict with the
     ‘Yield’ name used by the Windows ‘<winbase.h>’ header.  Use the
     Python *note ast: 8. module instead.  Patch by Victor Stinner.

   - bpo-43541(6): Fix a ‘PyEval_EvalCodeEx()’ regression: fix reference
     counting on builtins.  Patch by Victor Stinner.

   - bpo-43244(7): Remove the ‘symtable.h’ header file and the
     undocumented functions:

        * ‘PyST_GetScope()’

        * ‘PySymtable_Build()’

        * ‘PySymtable_BuildObject()’

        * ‘PySymtable_Free()’

        * ‘Py_SymtableString()’

        * ‘Py_SymtableStringObject()’

     The ‘Py_SymtableString()’ function was part the stable ABI by
     mistake but it could not be used, because the ‘symtable.h’ header
     file was excluded from the limited C API.

     The Python *note symtable: d8. module remains available and is
     unchanged.

     Patch by Victor Stinner.

   - bpo-43244(8): Remove the ‘PyAST_Validate()’ function.  It is no
     longer possible to build a AST object (‘mod_ty’ type) with the
     public C API. The function was already excluded from the limited C
     API ( PEP 384(9)).  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43688

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36465

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43541

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43244

   (9) https://peps.python.org/pep-0384/


File: python.info,  Node: Python 3 10 0 alpha 6,  Next: Python 3 10 0 alpha 5,  Prev: Python 3 10 0 alpha 7,  Up: Changelog

1.23.46 Python 3.10.0 alpha 6
-----------------------------

'Release date: 2021-03-01'

* Menu:

* Security: Security<29>.
* Core and Builtins: Core and Builtins<96>.
* Library: Library<98>.
* Core and Builtins: Core and Builtins<97>.
* Library: Library<99>.
* Core and Builtins: Core and Builtins<98>.
* Library: Library<100>.
* Documentation: Documentation<37>.
* Tests: Tests<40>.
* Build: Build<44>.
* Windows: Windows<38>.
* macOS: macOS<29>.
* IDLE: IDLE<26>.
* C API: C API<39>.


File: python.info,  Node: Security<29>,  Next: Core and Builtins<96>,  Up: Python 3 10 0 alpha 6

1.23.46.1 Security
..................

   - bpo-42967(1): Fix web cache poisoning vulnerability by defaulting
     the query args separator to ‘&’, and allowing the user to choose a
     custom separator.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42967


File: python.info,  Node: Core and Builtins<96>,  Next: Library<98>,  Prev: Security<29>,  Up: Python 3 10 0 alpha 6

1.23.46.2 Core and Builtins
...........................

   - bpo-43321(1): Fix ‘SystemError’ raised when ‘PyArg_Parse*()’ is
     used with ‘#’ but without ‘PY_SSIZE_T_CLEAN’ defined.

   - bpo-36346(2): ‘PyArg_Parse*()’ functions now emits
     ‘DeprecationWarning’ when ‘u’ or ‘Z’ format is used.  See PEP
     623(3) for detail.

   - bpo-43277(4): Add a new *note PySet_CheckExact(): 8a4. function to
     the C-API to check if an object is an instance of *note set: 5dc.
     but not an instance of a subtype.  Patch by Pablo Galindo.

   - bpo-42990(5): The *note types.FunctionType: 88a. constructor now
     inherits the current builtins if the 'globals' dictionary has no
     ‘"__builtins__"’ key, rather than using ‘{"None": None}’ as
     builtins: same behavior as *note eval(): 180. and *note exec():
     17f. functions.  Defining a function with ‘def function(...): ...’
     in Python is not affected, globals cannot be overridden with this
     syntax: it also inherits the current builtins.  Patch by Victor
     Stinner.

   - bpo-42990(6): Functions have a new ‘__builtins__’ attribute which
     is used to look for builtin symbols when a function is executed,
     instead of looking into ‘__globals__['__builtins__']’.  Patch by
     Mark Shannon and Victor Stinner.

   - bpo-43149(7): Improve the error message in the parser for exception
     groups without parentheses.  Patch by Pablo Galindo.

   - bpo-43121(8): Fixed an incorrect *note SyntaxError: 18d. message
     for missing comma in literals.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43321

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (3) https://peps.python.org/pep-0623/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43277

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42990

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42990

   (7) https://bugs.python.org/issue?@action=redirect&bpo=43149

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43121


File: python.info,  Node: Library<98>,  Next: Core and Builtins<97>,  Prev: Core and Builtins<96>,  Up: Python 3 10 0 alpha 6

1.23.46.3 Library
.................

   - bpo-42819(1): *note readline: ba.: Explicitly disable bracketed
     paste in the interactive interpreter, even if it’s set in the
     inputrc, is enabled by default (eg GNU Readline 8.1), or a user
     calls ‘readline.read_init_file()’.  The Python REPL has not
     implemented bracketed paste support.  Also, bracketed mode writes
     the ‘"\x1b[?2004h"’ escape sequence into stdout which causes test
     failures in applications that don’t support it.  It can still be
     explicitly enabled by calling ‘readline.parse_and_bind("set
     enable-bracketed-paste on")’.  Patch by Dustin Rodrigues.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42819


File: python.info,  Node: Core and Builtins<97>,  Next: Library<99>,  Prev: Library<98>,  Up: Python 3 10 0 alpha 6

1.23.46.4 Core and Builtins
...........................

   - bpo-42808(1): Simple calls to ‘type(object)’ are now faster due to
     the ‘vectorcall’ calling convention.  Patch by Dennis Sweeney.

   - bpo-42217(2): Make the compiler merges same co_code and
     co_linetable objects in a module like already did for co_consts.

   - bpo-41972(3): Substring search functions such as ‘str1 in str2’ and
     ‘str2.find(str1)’ now sometimes use the “Two-Way” string comparison
     algorithm to avoid quadratic behavior on long strings.

   - bpo-42128(4): Implement PEP 634(5) (structural pattern matching).
     Patch by Brandt Bucher.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42808

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42217

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41972

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42128

   (5) https://peps.python.org/pep-0634/


File: python.info,  Node: Library<99>,  Next: Core and Builtins<98>,  Prev: Core and Builtins<97>,  Up: Python 3 10 0 alpha 6

1.23.46.5 Library
.................

   - bpo-40692(1): In the *note concurrent.futures.ProcessPoolExecutor:
     8f7, validate that ‘multiprocess.synchronize()’ is available on a
     given platform and rely on that check in the *note
     concurrent.futures: 21. test suite so we can run tests that are
     unrelated to ‘ProcessPoolExecutor’ on those platforms.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40692


File: python.info,  Node: Core and Builtins<98>,  Next: Library<100>,  Prev: Library<99>,  Up: Python 3 10 0 alpha 6

1.23.46.6 Core and Builtins
...........................

   - bpo-38302(1): If *note object.__ipow__(): 7d5. returns *note
     NotImplemented: 7d6, the operator will correctly fall back to *note
     object.__pow__(): 7d7. and *note object.__rpow__(): 7d8. as
     expected.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38302


File: python.info,  Node: Library<100>,  Next: Documentation<37>,  Prev: Core and Builtins<98>,  Up: Python 3 10 0 alpha 6

1.23.46.7 Library
.................

   - bpo-43316(1): The ‘python -m gzip’ command line application now
     properly fails when detecting an unsupported extension.  It exits
     with a non-zero exit code and prints an error message to stderr.

   - bpo-43317(2): Set the chunk size for the ‘gzip’ module main
     function to io.DEFAULT_BUFFER_SIZE. This is slightly faster than
     the 1024 bytes constant that was used previously.

   - bpo-43146(3): Handle None in single-arg versions of *note
     print_exception(): 855. and *note format_exception(): 853.

   - bpo-43260(4): Fix TextIOWrapper can not flush internal buffer
     forever after very large text is written.

   - bpo-43258(5): Prevent needless allocation of *note sqlite3: cf.
     aggregate function context when no rows match an aggregate query.
     Patch by Erlend E. Aasland.

   - bpo-43251(6): Improve *note sqlite3: cf. error handling:
     ‘sqlite3_column_name()’ failures now result in *note MemoryError:
     15ab.  Patch by Erlend E. Aasland.

   - bpo-40956(7): Fix segfault in *note sqlite3.Connection.backup():
     b98. if no argument was provided.  The regression was introduced by
     PR 23838.  Patch by Erlend E. Aasland.

   - bpo-43172(8): The readline module now passes its tests when built
     directly against libedit.  Existing irreconcilable API differences
     remain in *note readline.get_begidx(): 1a4a. and *note
     readline.get_endidx(): 1a4b. behavior based on libreadline vs
     libedit use.

   - bpo-43163(9): Fix a bug in *note codeop: 1c. that was causing it to
     not ask for more input when multi-line snippets have unclosed
     parentheses.  Patch by Pablo Galindo

   - bpo-43162(10): deprecate unsupported ability to access enum members
     as attributes of other enum members

   - bpo-43146(11): Fix recent regression in None argument handling in
     *note traceback: fe. module functions.

   - bpo-43102(12): The namedtuple __new__ method had its __builtins__
     set to None instead of an actual dictionary.  This created problems
     for introspection tools.

   - bpo-43106(13): Added *note O_EVTONLY: 820, *note O_FSYNC: 821,
     *note O_SYMLINK: 822. and *note O_NOFOLLOW_ANY: 823. for macOS.
     Patch by Donghee Na.

   - bpo-42960(14): Adds *note resource.RLIMIT_KQUEUES: 1a4c. constant
     from FreeBSD to the *note resource: bc. module.

   - bpo-42151(15): Make the pure Python implementation of *note
     xml.etree.ElementTree: 125. behave the same as the C implementation
     (‘_elementree’) regarding default attribute values (by not setting
     ‘specified_attributes=1’).

   - bpo-29753(16): In ctypes, now packed bitfields are calculated
     properly and the first item of packed bitfields is now shrank
     correctly.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43316

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43317

   (3) https://bugs.python.org/issue?@action=redirect&bpo=43146

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43260

   (5) https://bugs.python.org/issue?@action=redirect&bpo=43258

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43251

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40956

   (8) https://bugs.python.org/issue?@action=redirect&bpo=43172

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43163

   (10) https://bugs.python.org/issue?@action=redirect&bpo=43162

   (11) https://bugs.python.org/issue?@action=redirect&bpo=43146

   (12) https://bugs.python.org/issue?@action=redirect&bpo=43102

   (13) https://bugs.python.org/issue?@action=redirect&bpo=43106

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42960

   (15) https://bugs.python.org/issue?@action=redirect&bpo=42151

   (16) https://bugs.python.org/issue?@action=redirect&bpo=29753


File: python.info,  Node: Documentation<37>,  Next: Tests<40>,  Prev: Library<100>,  Up: Python 3 10 0 alpha 6

1.23.46.8 Documentation
.......................

   - bpo-27646(1): Clarify that ‘yield from <expr>’ works with any
     iterable, not just iterators.

   - bpo-36346(2): Update some deprecated unicode APIs which are
     documented as “will be removed in 4.0” to “3.12”.  See PEP 623(3)
     for detail.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27646

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (3) https://peps.python.org/pep-0623/


File: python.info,  Node: Tests<40>,  Next: Build<44>,  Prev: Documentation<37>,  Up: Python 3 10 0 alpha 6

1.23.46.9 Tests
...............

   - bpo-43288(1): Fix test_importlib to correctly skip Unicode file
     tests if the filesystem does not support them.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43288


File: python.info,  Node: Build<44>,  Next: Windows<38>,  Prev: Tests<40>,  Up: Python 3 10 0 alpha 6

1.23.46.10 Build
................

   - bpo-43174(1): Windows build now uses ‘/utf-8’ compiler option.

   - bpo-43103(2): Add a new configure ‘--without-static-libpython’
     option to not build the ‘libpythonMAJOR.MINOR.a’ static library and
     not install the ‘python.o’ object file.

   - bpo-13501(3): The configure script can now use 'libedit' instead of
     'readline' with the command line option ‘--with-readline=editline’.

   - bpo-42603(4): Make configure script use pkg-config to detect the
     location of Tcl/Tk headers and libraries, used to build tkinter.

     On macOS, a Tcl/Tk configuration provided by pkg-config will be
     preferred over Tcl/Tk frameworks installed in
     ‘/{System/,}Library/Frameworks’.  If both exist and the latter is
     preferred, the appropriate ‘--with-tcltk-*’ configuration options
     need to be explicitly set.

   - bpo-39448(5): Add the “regen-frozen” makefile target that
     regenerates the code for the frozen ‘__hello__’ module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43174

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43103

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13501

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42603

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39448


File: python.info,  Node: Windows<38>,  Next: macOS<29>,  Prev: Build<44>,  Up: Python 3 10 0 alpha 6

1.23.46.11 Windows
..................

   - bpo-43155(1): *note PyCMethod_New(): 1a51. is now present in
     ‘python3.lib’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43155


File: python.info,  Node: macOS<29>,  Next: IDLE<26>,  Prev: Windows<38>,  Up: Python 3 10 0 alpha 6

1.23.46.12 macOS
................

   - bpo-41837(1): Update macOS installer build to use OpenSSL 1.1.1j.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41837


File: python.info,  Node: IDLE<26>,  Next: C API<39>,  Prev: macOS<29>,  Up: Python 3 10 0 alpha 6

1.23.46.13 IDLE
...............

   - bpo-43283(1): Document why printing to IDLE’s Shell is often slower
     than printing to a system terminal and that it can be made faster
     by pre-formatting a single string before printing.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43283


File: python.info,  Node: C API<39>,  Prev: IDLE<26>,  Up: Python 3 10 0 alpha 6

1.23.46.14 C API
................

   - bpo-43278(1): Always put compiler and system information on the
     first line of the REPL welcome message.

   - bpo-43270(2): Remove the private ‘_PyErr_OCCURRED()’ macro: use the
     public *note PyErr_Occurred(): 1a55. function instead.

   - bpo-35134(3): Move odictobject.h, parser_interface.h,
     picklebufobject.h, pydebug.h, and pyfpe.h into the cpython/
     directory.  They must not be included directly, as they are already
     included by Python.h: *note Include Files: 787.

   - bpo-35134(4): Move pyarena.h, pyctype.h, and pytime.h into the
     cpython/ directory.  They must not be included directly, as they
     are already included by Python.h: *note Include Files: 787.

   - bpo-40170(5): *note PyExceptionClass_Name(): a74. is now always
     declared as a function, in order to hide implementation details.
     The macro accessed *note PyTypeObject.tp_name: 1a56. directly.
     Patch by Erlend E. Aasland.

   - bpo-43239(6): The *note PyCFunction_New(): 1a57. function is now
     exported in the ABI when compiled with ‘-fvisibility=hidden’.

   - bpo-40170(7): *note PyIter_Check(): 1a58. is now always declared as
     a function, in order to hide implementation details.  The macro
     accessed *note PyTypeObject.tp_iternext: 153f. directly.  Patch by
     Erlend E. Aasland.

   - bpo-40170(8): Convert *note PyDescr_IsData(): 1a59. macro to a
     function to hide implementation details: The macro accessed *note
     PyTypeObject.tp_descr_set: 1a5a. directly.  Patch by Erlend E.
     Aasland.

   - bpo-43181(9): Convert *note PyObject_TypeCheck(): 1a5b. macro to a
     static inline function.  Patch by Erlend E. Aasland.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43278

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43270

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (6) https://bugs.python.org/issue?@action=redirect&bpo=43239

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (9) https://bugs.python.org/issue?@action=redirect&bpo=43181


File: python.info,  Node: Python 3 10 0 alpha 5,  Next: Python 3 10 0 alpha 4,  Prev: Python 3 10 0 alpha 6,  Up: Changelog

1.23.47 Python 3.10.0 alpha 5
-----------------------------

'Release date: 2021-02-02'

* Menu:

* Security: Security<30>.
* Core and Builtins: Core and Builtins<99>.
* Library: Library<101>.
* Core and Builtins: Core and Builtins<100>.
* Library: Library<102>.
* Documentation: Documentation<38>.
* Tests: Tests<41>.
* Build: Build<45>.
* Windows: Windows<39>.
* macOS: macOS<30>.
* IDLE: IDLE<27>.
* C API: C API<40>.


File: python.info,  Node: Security<30>,  Next: Core and Builtins<99>,  Up: Python 3 10 0 alpha 5

1.23.47.1 Security
..................

   - bpo-42938(1): Avoid static buffers when computing the repr of *note
     ctypes.c_double: 1a5e. and *note ctypes.c_longdouble: 1a5f. values.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42938


File: python.info,  Node: Core and Builtins<99>,  Next: Library<101>,  Prev: Security<30>,  Up: Python 3 10 0 alpha 5

1.23.47.2 Core and Builtins
...........................

   - bpo-42990(1): Refactor the ‘PyEval_’ family of functions.

        * An new function ‘_PyEval_Vector’ is added to simplify calls to
          Python from C.

        * ‘_PyEval_EvalCodeWithName’ is removed

        * ‘PyEval_EvalCodeEx’ is retained as part of the API, but is not
          used internally

   - bpo-38631(2): Replace *note Py_FatalError(): 98d. calls in the
     compiler with regular *note SystemError: 578. exceptions.  Patch by
     Victor Stinner.

   - bpo-42997(3): Improve error message for missing “:” before blocks.
     Patch by Pablo Galindo.

   - bpo-43017(4): Improve error message in the parser when using
     un-parenthesised tuples in comprehensions.  Patch by Pablo Galindo.

   - bpo-42986(5): Fix parser crash when reporting syntax errors in
     f-string with newlines.  Patch by Pablo Galindo.

   - bpo-40176(6): Syntax errors for unterminated string literals now
     point to the start of the string instead of reporting EOF/EOL.

   - bpo-42927(7): The inline cache for ‘LOAD_ATTR’ now also optimizes
     access to attributes defined by ‘__slots__’.  This makes reading
     such attribute up to 30% faster.

   - bpo-42864(8): Improve error messages in the parser when parentheses
     are not closed.  Patch by Pablo Galindo.

   - bpo-42924(9): Fix ‘bytearray’ repetition incorrectly copying data
     from the start of the buffer, even if the data is offset within the
     buffer (e.g.  after reassigning a slice at the start of the
     ‘bytearray’ to a shorter byte string).

   - bpo-42882(10): Fix the ‘_PyUnicode_FromId()’ function
     (_Py_IDENTIFIER(var) API) when *note Py_Initialize(): 8b4. / *note
     Py_Finalize(): 13a6. is called multiple times: preserve
     ‘_PyRuntime.unicode_ids.next_index’ value.

   - bpo-42827(11): Fix a crash when working out the error line of a
     *note SyntaxError: 18d. in some multi-line expressions.

   - bpo-42823(12): frame.f_lineno is correct even if frame.f_trace is
     set to True

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42990

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38631

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42997

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43017

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42986

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40176

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42927

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42864

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42924

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42882

   (11) https://bugs.python.org/issue?@action=redirect&bpo=42827

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42823


File: python.info,  Node: Library<101>,  Next: Core and Builtins<100>,  Prev: Core and Builtins<99>,  Up: Python 3 10 0 alpha 5

1.23.47.3 Library
.................

   - bpo-37324(1): Remove deprecated aliases to *note Collections
     Abstract Base Classes: 87f. from the *note collections: 1d. module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37324


File: python.info,  Node: Core and Builtins<100>,  Next: Library<102>,  Prev: Library<101>,  Up: Python 3 10 0 alpha 5

1.23.47.4 Core and Builtins
...........................

   - bpo-41994(1): Fixed possible leak in ‘import’ when ‘sys.modules’ is
     not a ‘dict’.

   - bpo-27772(2): In string formatting, preceding the 'width' field by
     ‘'0'’ no longer affects the default alignment for strings.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41994

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27772


File: python.info,  Node: Library<102>,  Next: Documentation<38>,  Prev: Core and Builtins<100>,  Up: Python 3 10 0 alpha 5

1.23.47.5 Library
.................

   - bpo-43108(1): Fixed a reference leak in the *note curses: 2b.
     module.  Patch by Pablo Galindo

   - bpo-43077(2): Update the bundled pip to 21.0.1 and setuptools to
     52.0.0.

   - bpo-41282(3): Deprecate ‘distutils’ in documentation and add
     warning on import.

   - bpo-43014(4): Improve performance of *note tokenize: fb. by 20-30%.
     Patch by Anthony Sottile.

   - bpo-42323(5): Fix *note math.nextafter(): 49b. for NaN on AIX.

   - bpo-42955(6): Add *note sys.stdlib_module_names: 847, containing
     the list of the standard library module names.  Patch by Victor
     Stinner.

   - bpo-42944(7): Fix ‘random.Random.sample’ when ‘counts’ argument is
     not ‘None’.

   - bpo-42934(8): Use *note TracebackException: 25c.’s new ‘compact’
     param in *note TestResult: 11ab. to reduce time and memory consumed
     by traceback formatting.

   - bpo-42931(9): Add ‘randbytes()’ to ‘random.__all__’.

   - bpo-38250(10): [Enum] Flags consisting of a single bit are now
     considered canonical, and will be the only flags returned from
     listing and iterating over a Flag class or a Flag member.
     Multi-bit flags are considered aliases; they will be returned from
     lookups and operations that result in their value.  Iteration for
     both Flag and Flag members is in definition order.

   - bpo-42877(11): Added the ‘compact’ parameter to the constructor of
     *note traceback.TracebackException: 25c. to reduce time and memory
     for use cases that only need to call ‘TracebackException.format()’
     and ‘TracebackException.format_exception_only()’.

   - bpo-42923(12): The *note Py_FatalError(): 98d. function and the
     *note faulthandler: 58. module now dump the list of extension
     modules on a fatal error.

   - bpo-42848(13): Removed recursion from *note TracebackException:
     25c. to allow it to handle long exception chains.

   - bpo-42901(14): [Enum] move member creation from ‘EnumMeta.__new__’
     to ‘_proto_member.__set_name__’, allowing members to be created and
     visible in ‘__init_subclass__’.

   - bpo-42780(15): Fix os.set_inheritable() for O_PATH file descriptors
     on Linux.

   - bpo-42866(16): Fix a reference leak in the ‘getcodec()’ function of
     CJK codecs.  Patch by Victor Stinner.

   - bpo-42846(17): Convert the 6 CJK codec extension modules
     (_codecs_cn, _codecs_hk, _codecs_iso2022, _codecs_jp, _codecs_kr
     and _codecs_tw) to the multiphase initialization API ( PEP
     489(18)).  Patch by Victor Stinner.

   - bpo-42851(19): remove __init_subclass__ support for Enum members

   - bpo-42834(20): Make internal caches of the ‘_json’ module
     compatible with subinterpreters.

   - bpo-41748(21): Fix HTMLParser parsing rules for element attributes
     containing commas with spaces.  Patch by Karl Dubost.

   - bpo-40810(22): Require SQLite 3.7.15 or newer.  Patch by Erlend E.
     Aasland.

   - bpo-1635741(23): Convert the _multibytecodec extension module (CJK
     codecs) to multi-phase initialization ( PEP 489(24)).  Patch by
     Erlend E. Aasland.

   - bpo-42802(25): The distutils ‘bdist_wininst’ command deprecated in
     Python 3.8 has been removed.  The distutils ‘bdist_wheel’ command
     is now recommended to distribute binary packages on Windows.

   - bpo-24464(26): The undocumented built-in function
     ‘sqlite3.enable_shared_cache’ is now deprecated, scheduled for
     removal in Python 3.12.  Its use is strongly discouraged by the
     SQLite3 documentation.  Patch by Erlend E. Aasland.

   - bpo-42384(27): Make pdb populate sys.path[0] exactly the same as
     regular python execution.

   - bpo-42383(28): Fix pdb: previously pdb would fail to restart the
     debugging target if it was specified using a relative path and the
     current directory changed.

   - bpo-42005(29): Fix CLI of *note cProfile: 27. and *note profile:
     af. to catch *note BrokenPipeError: 109a.

   - bpo-41604(30): Don’t decrement the reference count of the previous
     user_ptr when set_panel_userptr fails.

   - bpo-41149(31): Allow executing callables that have a boolean value
     of ‘False’ when passed to ‘Threading.thread’ as the target.  Patch
     contributed by Barney Stratford.

   - bpo-38307(32): Add an ‘end_lineno’ attribute to the Class and
     Function objects that appear in the tree returned by pyclbr
     functions.  This and the existing ‘lineno’ attribute define the
     extent of class and def statements.  Patch by Aviral Srivastava.

   - bpo-39273(33): The ‘BUTTON5_*’ constants are now exposed in the
     *note curses: 2b. module if available.

   - bpo-33289(34): Correct call to *note tkinter.colorchooser: f1. to
     return RGB triplet of ints instead of floats.  Patch by Cheryl
     Sabella.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43108

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43077

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41282

   (4) https://bugs.python.org/issue?@action=redirect&bpo=43014

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42323

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42955

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42944

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42934

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42931

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38250

   (11) https://bugs.python.org/issue?@action=redirect&bpo=42877

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42923

   (13) https://bugs.python.org/issue?@action=redirect&bpo=42848

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42901

   (15) https://bugs.python.org/issue?@action=redirect&bpo=42780

   (16) https://bugs.python.org/issue?@action=redirect&bpo=42866

   (17) https://bugs.python.org/issue?@action=redirect&bpo=42846

   (18) https://peps.python.org/pep-0489/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=42851

   (20) https://bugs.python.org/issue?@action=redirect&bpo=42834

   (21) https://bugs.python.org/issue?@action=redirect&bpo=41748

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40810

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (24) https://peps.python.org/pep-0489/

   (25) https://bugs.python.org/issue?@action=redirect&bpo=42802

   (26) https://bugs.python.org/issue?@action=redirect&bpo=24464

   (27) https://bugs.python.org/issue?@action=redirect&bpo=42384

   (28) https://bugs.python.org/issue?@action=redirect&bpo=42383

   (29) https://bugs.python.org/issue?@action=redirect&bpo=42005

   (30) https://bugs.python.org/issue?@action=redirect&bpo=41604

   (31) https://bugs.python.org/issue?@action=redirect&bpo=41149

   (32) https://bugs.python.org/issue?@action=redirect&bpo=38307

   (33) https://bugs.python.org/issue?@action=redirect&bpo=39273

   (34) https://bugs.python.org/issue?@action=redirect&bpo=33289


File: python.info,  Node: Documentation<38>,  Next: Tests<41>,  Prev: Library<102>,  Up: Python 3 10 0 alpha 5

1.23.47.6 Documentation
.......................

   - bpo-40304(1): Fix doc for type(name, bases, dict).  Patch by Boris
     Verkhovskiy and Éric Araujo.

   - bpo-42811(2): Updated importlib.util.resolve_name() doc to use
     __spec__.parent instead of __package__.  (Thanks Yair Frid.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40304

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42811


File: python.info,  Node: Tests<41>,  Next: Build<45>,  Prev: Documentation<38>,  Up: Python 3 10 0 alpha 5

1.23.47.7 Tests
...............

   - bpo-40823(1): Use ‘unittest.TestLoader().loadTestsFromTestCase()’
     instead of ‘unittest.makeSuite()’ in *note sqlite3: cf. tests.
     Patch by Erlend E. Aasland.

   - bpo-40810(2): In *note sqlite3: cf, fix ‘CheckTraceCallbackContent’
     for SQLite pre 3.7.15.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40823

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40810


File: python.info,  Node: Build<45>,  Next: Windows<39>,  Prev: Tests<41>,  Up: Python 3 10 0 alpha 5

1.23.47.8 Build
...............

   - bpo-43031(1): Pass ‘--timeout=$(TESTTIMEOUT)’ option to the default
     profile task ‘./python -m test --pgo’ command.

   - bpo-36143(2): ‘make regen-all’ now also runs ‘regen-keyword’.
     Patch by Victor Stinner.

   - bpo-42874(3): Removed the grep -q and -E flags in the tzpath
     validation section of the configure script to better accommodate
     users of some platforms (specifically Solaris 10).

   - bpo-31904(4): Add library search path by wr-cc in
     add_cross_compiling_paths() for VxWorks.

   - bpo-42856(5): Add ‘--with-wheel-pkg-dir=PATH’ option to the
     ‘./configure’ script.  If specified, the *note ensurepip: 55.
     module looks for ‘setuptools’ and ‘pip’ wheel packages in this
     directory: if both are present, these wheel packages are used
     instead of ensurepip bundled wheel packages.

     Some Linux distribution packaging policies recommend against
     bundling dependencies.  For example, Fedora installs wheel packages
     in the ‘/usr/share/python-wheels/’ directory and don’t install the
     ‘ensurepip._bundled’ package.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43031

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36143

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42874

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42856


File: python.info,  Node: Windows<39>,  Next: macOS<30>,  Prev: Build<45>,  Up: Python 3 10 0 alpha 5

1.23.47.9 Windows
.................

   - bpo-41837(1): Updated Windows installer to include OpenSSL 1.1.1i

   - bpo-42584(2): Upgrade Windows installer to use SQLite 3.34.0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41837

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42584


File: python.info,  Node: macOS<30>,  Next: IDLE<27>,  Prev: Windows<39>,  Up: Python 3 10 0 alpha 5

1.23.47.10 macOS
................

   - bpo-42504(1): Ensure that the value of
     sysconfig.get_config_var(‘MACOSX_DEPLOYMENT_TARGET’) is always a
     string, even in when the value is parsable as an integer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42504


File: python.info,  Node: IDLE<27>,  Next: C API<40>,  Prev: macOS<30>,  Up: Python 3 10 0 alpha 5

1.23.47.11 IDLE
...............

   - bpo-43008(1): Make IDLE invoke *note sys.excepthook(): 811. in
     normal, 2-process mode.  Patch by Ken Hilton.

   - bpo-33065(2): Fix problem debugging user classes with __repr__
     method.

   - bpo-23544(3): Disable Debug=>Stack Viewer when user code is running
     or Debugger is active, to prevent hang or crash.  Patch by Zackery
     Spytz.

   - bpo-32631(4): Finish zzdummy example extension module: make menu
     entries work; add docstrings and tests with 100% coverage.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=43008

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33065

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23544

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32631


File: python.info,  Node: C API<40>,  Prev: IDLE<27>,  Up: Python 3 10 0 alpha 5

1.23.47.12 C API
................

   - bpo-42979(1): When Python is built in debug mode (with C
     assertions), calling a type slot like ‘sq_length’ (‘__len__()’ in
     Python) now fails with a fatal error if the slot succeeded with an
     exception set, or failed with no exception set.  The error message
     contains the slot, the type name, and the current exception (if an
     exception is set).  Patch by Victor Stinner.

   - bpo-43030(2): Fixed a compiler warning in *note
     Py_UNICODE_ISSPACE(): 1a6b. on platforms with signed ‘wchar_t’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42979

   (2) https://bugs.python.org/issue?@action=redirect&bpo=43030


File: python.info,  Node: Python 3 10 0 alpha 4,  Next: Python 3 10 0 alpha 3,  Prev: Python 3 10 0 alpha 5,  Up: Changelog

1.23.48 Python 3.10.0 alpha 4
-----------------------------

'Release date: 2021-01-04'

* Menu:

* Core and Builtins: Core and Builtins<101>.
* Library: Library<103>.
* Core and Builtins: Core and Builtins<102>.
* Library: Library<104>.
* Core and Builtins: Core and Builtins<103>.
* Library: Library<105>.
* Documentation: Documentation<39>.
* Tests: Tests<42>.
* Build: Build<46>.
* macOS: macOS<31>.
* Tools/Demos: Tools/Demos<21>.
* C API: C API<41>.


File: python.info,  Node: Core and Builtins<101>,  Next: Library<103>,  Up: Python 3 10 0 alpha 4

1.23.48.1 Core and Builtins
...........................

   - bpo-42814(1): Fix undefined behavior in
     ‘Objects/genericaliasobject.c’.

   - bpo-42806(2): Fix the column offsets for f-strings *note ast: 8.
     nodes surrounded by parentheses and for nodes that spawn multiple
     lines.  Patch by Pablo Galindo.

   - bpo-40631(3): Fix regression where a single parenthesized starred
     expression was a valid assignment target.

   - bpo-27794(4): Improve the error message for failed writes/deletes
     to property objects.  When possible, the attribute name is now
     shown.  Patch provided by Yurii Karabas.

   - bpo-42745(5): Make the type attribute lookup cache per-interpreter.
     Patch by Victor Stinner.

   - bpo-42246(6): Jumps to jumps are not eliminated when it would break
     PEP 626.

   - bpo-42246(7): Make sure that the ‘f_lasti’ and ‘f_lineno’
     attributes of a frame are set correctly when an exception is raised
     or re-raised.  Required for PEP 626.

   - bpo-32381(8): The coding cookie (ex: ‘# coding: latin1’) is now
     ignored in the command passed to the *note -c: 5e3. command line
     option.  Patch by Victor Stinner.

   - bpo-30858(9): Improve error location in expressions that contain
     assignments.  Patch by Pablo Galindo and Lysandros Nikolaou.

   - bpo-42615(10): Remove jump commands made redundant by the deletion
     of unreachable bytecode blocks

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42814

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42806

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40631

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27794

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42745

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42246

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42246

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32381

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30858

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42615


File: python.info,  Node: Library<103>,  Next: Core and Builtins<102>,  Prev: Core and Builtins<101>,  Up: Python 3 10 0 alpha 4

1.23.48.2 Library
.................

   - bpo-42639(1): Make the *note atexit: c. module state
     per-interpreter.  It is now safe have more than one ‘atexit’ module
     instance.  Patch by Donghee Na and Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42639


File: python.info,  Node: Core and Builtins<102>,  Next: Library<104>,  Prev: Library<103>,  Up: Python 3 10 0 alpha 4

1.23.48.3 Core and Builtins
...........................

   - bpo-32381(1): Fix encoding name when running a ‘.pyc’ file on
     Windows: *note PyRun_SimpleFileExFlags(): 1a70. now uses the
     correct encoding to decode the filename.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32381


File: python.info,  Node: Library<104>,  Next: Core and Builtins<103>,  Prev: Core and Builtins<102>,  Up: Python 3 10 0 alpha 4

1.23.48.4 Library
.................

   - bpo-42195(1): The ‘__args__’ of the parameterized generics for
     *note typing.Callable: 7c9. and *note collections.abc.Callable:
     7ef. are now consistent.  The ‘__args__’ for
     ‘collections.abc.Callable’ are now flattened while
     ‘typing.Callable’’s have not changed.  To allow this change, *note
     types.GenericAlias: 7f0. can now be subclassed and
     ‘collections.abc.Callable’’s ‘__class_getitem__’ will now return a
     subclass of ‘types.GenericAlias’.  Tests for typing were also
     updated to not subclass things like ‘Callable[..., T]’ as that is
     not a valid base class.  Finally, both ‘Callable’s no longer
     validate their ‘argtypes’, in ‘Callable[[argtypes], resulttype]’ to
     prepare for PEP 612(2).  Patch by Ken Jin.

   - bpo-40137(3): Convert functools module to use *note
     PyType_FromModuleAndSpec(): 554.

   - bpo-40077(4): Convert *note array: 7. to use heap types, and
     establish module state for these.

   - bpo-42008(5): Fix _random.Random() seeding.

   - bpo-1635741(6): Port the ‘pyexpat’ extension module to multi-phase
     initialization ( PEP 489(7)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42195

   (2) https://peps.python.org/pep-0612/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40137

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40077

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42008

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (7) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<103>,  Next: Library<105>,  Prev: Library<104>,  Up: Python 3 10 0 alpha 4

1.23.48.5 Core and Builtins
...........................

   - bpo-40521(1): Make the Unicode dictionary of interned strings
     compatible with subinterpreters.  Patch by Victor Stinner.

   - bpo-39465(2): Make ‘_PyUnicode_FromId()’ function compatible with
     subinterpreters.  Each interpreter now has an array of identifier
     objects (interned strings decoded from UTF-8).  Patch by Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40521

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39465


File: python.info,  Node: Library<105>,  Next: Documentation<39>,  Prev: Core and Builtins<103>,  Up: Python 3 10 0 alpha 4

1.23.48.6 Library
.................

   - bpo-42257(1): Handle empty string in variable executable in
     platform.libc_ver()

   - bpo-42772(2): randrange() now raises a TypeError when step is
     specified without a stop argument.  Formerly, it silently ignored
     the step argument.

   - bpo-42759(3): Fixed equality comparison of ‘tkinter.Variable’ and
     *note tkinter.font.Font: 1a74.  Objects which belong to different
     Tcl interpreters are now always different, even if they have the
     same name.

   - bpo-42756(4): Configure LMTP Unix-domain socket to use socket
     global default timeout when a timeout is not explicitly provided.

   - bpo-23328(5): Allow / character in username, password fields on
     _PROXY envars.

   - bpo-42740(6): *note typing.get_args(): 2ed. and *note
     typing.get_origin(): 2ec. now support PEP 604(7) union types and
     PEP 612(8) additions to ‘Callable’.

   - bpo-42655(9): *note subprocess: d6. 'extra_groups' is now correctly
     passed into setgroups() system call.

   - bpo-42727(10): ‘EnumMeta.__prepare__’ now accepts ‘**kwds’ to
     properly support ‘__init_subclass__’

   - bpo-38308(11): Add optional 'weights' to
     'statistics.harmonic_mean()'.

   - bpo-42721(12): When simple query dialogs (*note
     tkinter.simpledialog: f8.), message boxes (*note
     tkinter.messagebox: f6.) or color choose dialog (*note
     tkinter.colorchooser: f1.) are created without arguments 'master'
     and 'parent', and the default root window is not yet created, and
     ‘NoDefaultRoot()’ was not called, a new temporal hidden root window
     will be created automatically.  It will not be set as the default
     root window and will be destroyed right after closing the dialog
     window.  It will help to use these simple dialog windows in
     programs which do not need other GUI.

   - bpo-25246(13): Optimized *note collections.deque.remove(): 1a75.

   - bpo-35728(14): Added a root parameter to *note
     tkinter.font.nametofont(): 1a76.

   - bpo-15303(15): *note tkinter: f0. supports now widgets with boolean
     value False.

   - bpo-42681(16): Fixed range checks for color and pair numbers in
     *note curses: 2b.

   - bpo-42685(17): Improved placing of simple query windows in Tkinter
     (such as *note tkinter.simpledialog.askinteger(): 1a77.).  They are
     now centered at the center of the parent window if it is specified
     and shown, otherwise at the center of the screen.

   - bpo-9694(18): Argparse help no longer uses the confusing phrase,
     “optional arguments”.  It uses “options” instead.

   - bpo-1635741(19): Port the ‘_thread’ extension module to the
     multiphase initialization API ( PEP 489(20)) and convert its static
     types to heap types.

   - bpo-37961(21): Fix crash in ‘tracemalloc.Traceback.__repr__()’
     (regressed in Python 3.9).

   - bpo-42630(22): *note tkinter: f0. functions and constructors which
     need a default root window raise now *note RuntimeError: 195. with
     descriptive message instead of obscure *note AttributeError: 34e.
     or *note NameError: 442. if it is not created yet or cannot be
     created automatically.

   - bpo-42639(23): ‘atexit._run_exitfuncs()’ now logs callback
     exceptions using *note sys.unraisablehook: 1f7, rather than logging
     them directly into *note sys.stderr: 943. and raise the last
     exception.

   - bpo-42644(24): ‘logging.disable’ will now validate the types and
     value of its parameter.  It also now accepts strings representing
     the levels (as does ‘logging.setLevel’) instead of only the
     numerical values.

   - bpo-42639(25): At Python exit, if a callback registered with *note
     atexit.register(): 885. fails, its exception is now logged.
     Previously, only some exceptions were logged, and the last
     exception was always silently ignored.

   - bpo-36541(26): Fixed lib2to3.pgen2 to be able to parse PEP-570
     positional only argument syntax.

   - bpo-42382(27): In ‘importlib.metadata’: - ‘EntryPoint’ objects now
     expose a ‘.dist’ object referencing the ‘Distribution’ when
     constructed from a ‘Distribution’.  - Add support for package
     discovery under package normalization rules.  - The object returned
     by ‘metadata()’ now has a formally defined protocol called
     ‘PackageMetadata’ with declared support for the ‘.get_all()’
     method.  - Synced with importlib_metadata 3.3.

   - bpo-41877(28): A check is added against misspellings of autospect,
     auto_spec and set_spec being passed as arguments to patch,
     patch.object and create_autospec.

   - bpo-39717(29): [tarfile] update nested exception raising to use
     ‘from None’ or ‘from e’

   - bpo-41877(30): AttributeError for suspected misspellings of
     assertions on mocks are now pointing out that the cause are
     misspelled assertions and also what to do if the misspelling is
     actually an intended attribute name.  The unittest.mock document is
     also updated to reflect the current set of recognised misspellings.

   - bpo-41559(31): Implemented PEP 612(32): added ‘ParamSpec’ and
     ‘Concatenate’ to *note typing: 104.  Patch by Ken Jin.

   - bpo-42385(33): StrEnum: fix _generate_next_value_ to return a str

   - bpo-31904(34): Define THREAD_STACK_SIZE for VxWorks.

   - bpo-34750(35): [Enum] ‘_EnumDict.update()’ is now supported.

   - bpo-42517(36): Enum: private names do not become members / do not
     generate errors – they remain normal attributes

   - bpo-42678(37): ‘Enum’: call ‘__init_subclass__’ after members have
     been added

   - bpo-28964(38): *note ast.literal_eval(): c38. adds line number
     information (if available) in error message for malformed nodes.

   - bpo-42470(39): *note random.sample(): 749. no longer warns on a
     sequence which is also a set.

   - bpo-31904(40): ‘posixpath.expanduser()’ returns the input 'path'
     unchanged if user home directory is None on VxWorks.

   - bpo-42388(41): Fix subprocess.check_output(…, input=None) behavior
     when text=True to be consistent with that of the documentation and
     universal_newlines=True.

   - bpo-34463(42): Fixed discrepancy between *note traceback: fe. and
     the interpreter in formatting of SyntaxError with lineno not set
     (‘traceback’ was changed to match interpreter).

   - bpo-42393(43): Raise *note OverflowError: 888. instead of silent
     truncation in *note socket.ntohs(): 887. and *note socket.htons():
     886.  Silent truncation was deprecated in Python 3.7.  Patch by
     Erlend E. Aasland

   - bpo-42222(44): Harmonized *note random.randrange(): 872. argument
     handling to match *note range(): 94d.

        * The integer test and conversion in ‘randrange()’ now uses
          *note operator.index(): 1a78.

        * Non-integer arguments to ‘randrange()’ are deprecated.

        * The ‘ValueError’ is deprecated in favor of a ‘TypeError’.

        * It now runs a little faster than before.

     (Contributed by Raymond Hettinger and Serhiy Storchaka.)

   - bpo-42163(45): Restore compatibility for ‘uname_result’ around
     deepcopy and _replace.

   - bpo-42090(46): ‘zipfile.Path.joinpath’ now accepts arbitrary
     arguments, same as ‘pathlib.Path.joinpath’.

   - bpo-1635741(47): Port the _csv module to the multi-phase
     initialization API ( PEP 489(48)).

   - bpo-42059(49): *note typing.TypedDict: 162. types created using the
     alternative call-style syntax now correctly respect the ‘total’
     keyword argument when setting their ‘__required_keys__’ and
     ‘__optional_keys__’ class attributes.

   - bpo-41960(50): Add ‘globalns’ and ‘localns’ parameters to the *note
     inspect.signature(): 73b. and *note
     inspect.Signature.from_callable(): 73d.

   - bpo-41907(51): fix ‘format()’ behavior for ‘IntFlag’

   - bpo-41891(52): Ensure asyncio.wait_for waits for task completion

   - bpo-24792(53): Fixed bug where ‘zipimporter’ sometimes reports an
     incorrect cause of import errors.

   - bpo-31904(54): Fix site and sysconfig modules for VxWorks RTOS
     which has no home directories.

   - bpo-41462(55): Add *note os.set_blocking(): e6d. support for
     VxWorks RTOS.

   - bpo-40219(56): Lowered ‘tkinter.ttk.LabeledScale’ dummy widget to
     prevent hiding part of the content label.

   - bpo-37193(57): Fixed memory leak in ‘socketserver.ThreadingMixIn’
     introduced in Python 3.7.

   - bpo-39068(58): Fix initialization race condition in ‘a85encode()’
     and ‘b85encode()’ in *note base64: e.  Patch by Brandon Stansbury.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42257

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42772

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42759

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42756

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23328

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42740

   (7) https://peps.python.org/pep-0604/

   (8) https://peps.python.org/pep-0612/

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42655

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42727

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38308

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42721

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25246

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35728

   (15) https://bugs.python.org/issue?@action=redirect&bpo=15303

   (16) https://bugs.python.org/issue?@action=redirect&bpo=42681

   (17) https://bugs.python.org/issue?@action=redirect&bpo=42685

   (18) https://bugs.python.org/issue?@action=redirect&bpo=9694

   (19) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (20) https://peps.python.org/pep-0489/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37961

   (22) https://bugs.python.org/issue?@action=redirect&bpo=42630

   (23) https://bugs.python.org/issue?@action=redirect&bpo=42639

   (24) https://bugs.python.org/issue?@action=redirect&bpo=42644

   (25) https://bugs.python.org/issue?@action=redirect&bpo=42639

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36541

   (27) https://bugs.python.org/issue?@action=redirect&bpo=42382

   (28) https://bugs.python.org/issue?@action=redirect&bpo=41877

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39717

   (30) https://bugs.python.org/issue?@action=redirect&bpo=41877

   (31) https://bugs.python.org/issue?@action=redirect&bpo=41559

   (32) https://peps.python.org/pep-0612/

   (33) https://bugs.python.org/issue?@action=redirect&bpo=42385

   (34) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (35) https://bugs.python.org/issue?@action=redirect&bpo=34750

   (36) https://bugs.python.org/issue?@action=redirect&bpo=42517

   (37) https://bugs.python.org/issue?@action=redirect&bpo=42678

   (38) https://bugs.python.org/issue?@action=redirect&bpo=28964

   (39) https://bugs.python.org/issue?@action=redirect&bpo=42470

   (40) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (41) https://bugs.python.org/issue?@action=redirect&bpo=42388

   (42) https://bugs.python.org/issue?@action=redirect&bpo=34463

   (43) https://bugs.python.org/issue?@action=redirect&bpo=42393

   (44) https://bugs.python.org/issue?@action=redirect&bpo=42222

   (45) https://bugs.python.org/issue?@action=redirect&bpo=42163

   (46) https://bugs.python.org/issue?@action=redirect&bpo=42090

   (47) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (48) https://peps.python.org/pep-0489/

   (49) https://bugs.python.org/issue?@action=redirect&bpo=42059

   (50) https://bugs.python.org/issue?@action=redirect&bpo=41960

   (51) https://bugs.python.org/issue?@action=redirect&bpo=41907

   (52) https://bugs.python.org/issue?@action=redirect&bpo=41891

   (53) https://bugs.python.org/issue?@action=redirect&bpo=24792

   (54) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (55) https://bugs.python.org/issue?@action=redirect&bpo=41462

   (56) https://bugs.python.org/issue?@action=redirect&bpo=40219

   (57) https://bugs.python.org/issue?@action=redirect&bpo=37193

   (58) https://bugs.python.org/issue?@action=redirect&bpo=39068


File: python.info,  Node: Documentation<39>,  Next: Tests<42>,  Prev: Library<105>,  Up: Python 3 10 0 alpha 4

1.23.48.7 Documentation
.......................

   - bpo-17140(1): Add documentation for the *note
     multiprocessing.pool.ThreadPool: 1a7a. class.

   - bpo-34398(2): Prominently feature listings from the glossary in
     documentation search results.  Patch by Ammar Askar.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17140

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34398


File: python.info,  Node: Tests<42>,  Next: Build<46>,  Prev: Documentation<39>,  Up: Python 3 10 0 alpha 4

1.23.48.8 Tests
...............

   - bpo-42794(1): Update test_nntplib to use official group name of
     news.aioe.org for testing.  Patch by Donghee Na.

   - bpo-31904(2): Skip some asyncio tests on VxWorks.

   - bpo-42641(3): Enhance ‘test_select.test_select()’: it now takes 500
     milliseconds rather than 10 seconds.  Use Python rather than a
     shell to make the test more portable.

   - bpo-31904(4): Skip some tests in _test_all_chown_common() on
     VxWorks.

   - bpo-42199(5): Fix bytecode helper assertNotInBytecode.

   - bpo-41443(6): Add more attribute checking in test_posix.py

   - bpo-31904(7): Disable os.popen and impacted tests on VxWorks

   - bpo-41439(8): Port test_ssl and test_uuid to VxWorks RTOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42794

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42641

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42199

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41443

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41439


File: python.info,  Node: Build<46>,  Next: macOS<31>,  Prev: Tests<42>,  Up: Python 3 10 0 alpha 4

1.23.48.9 Build
...............

   - bpo-42692(1): Fix __builtin_available check on older compilers.
     Patch by Joshua Root.

   - bpo-27640(2): Added ‘--disable-test-modules’ option to the
     ‘configure’ script: don’t build nor install test modules.  Patch by
     Xavier de Gaye, Thomas Petazzoni and Peixing Xin.

   - bpo-42604(3): Now all platforms use a value for the “EXT_SUFFIX”
     build variable derived from SOABI (for instance in freeBSD,
     “EXT_SUFFIX” is now “.cpython-310d.so” instead of “.so”).
     Previously only Linux, Mac and VxWorks were using a value for
     “EXT_SUFFIX” that included “SOABI”.

   - bpo-42598(4): Fix implicit function declarations in configure which
     could have resulted in incorrect configuration checks.  Patch
     contributed by Joshua Root.

   - bpo-31904(5): Enable libpython3.so for VxWorks.

   - bpo-29076(6): Add fish shell support to macOS installer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42692

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27640

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42604

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42598

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29076


File: python.info,  Node: macOS<31>,  Next: Tools/Demos<21>,  Prev: Build<46>,  Up: Python 3 10 0 alpha 4

1.23.48.10 macOS
................

   - bpo-42361(1): Update macOS installer build to use Tcl/Tk 8.6.11
     (rc2, expected to be final release).

   - bpo-41837(2): Update macOS installer build to use OpenSSL 1.1.1i.

   - bpo-42584(3): Update macOS installer to use SQLite 3.34.0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42361

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41837

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42584


File: python.info,  Node: Tools/Demos<21>,  Next: C API<41>,  Prev: macOS<31>,  Up: Python 3 10 0 alpha 4

1.23.48.11 Tools/Demos
......................

   - bpo-42726(1): Fixed Python 3 compatibility issue with
     gdb/libpython.py handling of attribute dictionaries.

   - bpo-42613(2): Fix ‘freeze.py’ tool to use the prope config and
     library directories.  Patch by Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42726

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42613


File: python.info,  Node: C API<41>,  Prev: Tools/Demos<21>,  Up: Python 3 10 0 alpha 4

1.23.48.12 C API
................

   - bpo-42591(1): Export the ‘Py_FrozenMain()’ function: fix a Python
     3.9.0 regression.  Python 3.9 uses ‘-fvisibility=hidden’ and the
     function was not exported explicitly and so not exported.

   - bpo-32381(2): Remove the private ‘_Py_fopen()’ function which is no
     longer needed.  Use ‘_Py_wfopen()’ or ‘_Py_fopen_obj()’ instead.
     Patch by Victor Stinner.

   - bpo-1635741(3): Port *note resource: bc. extension module to module
     state

   - bpo-42111(4): Update the ‘xxlimited’ module to be a better example
     of how to use the limited C API.

   - bpo-40052(5): Fix an alignment build warning/error in function
     ‘PyVectorcall_Function()’.  Patch by Andreas Schneider, Antoine
     Pitrou and Petr Viktorin.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42591

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32381

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42111

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40052


File: python.info,  Node: Python 3 10 0 alpha 3,  Next: Python 3 10 0 alpha 2,  Prev: Python 3 10 0 alpha 4,  Up: Changelog

1.23.49 Python 3.10.0 alpha 3
-----------------------------

'Release date: 2020-12-07'

* Menu:

* Security: Security<31>.
* Core and Builtins: Core and Builtins<104>.
* Library: Library<106>.
* Core and Builtins: Core and Builtins<105>.
* Library: Library<107>.
* Core and Builtins: Core and Builtins<106>.
* Library: Library<108>.
* Core and Builtins: Core and Builtins<107>.
* Library: Library<109>.
* Documentation: Documentation<40>.
* Tests: Tests<43>.
* Build: Build<47>.
* Windows: Windows<40>.
* macOS: macOS<32>.
* IDLE: IDLE<28>.
* Tools/Demos: Tools/Demos<22>.
* C API: C API<42>.


File: python.info,  Node: Security<31>,  Next: Core and Builtins<104>,  Up: Python 3 10 0 alpha 3

1.23.49.1 Security
..................

   - bpo-40791(1): Add ‘volatile’ to the accumulator variable in
     ‘hmac.compare_digest’, making constant-time-defeating optimizations
     less likely.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40791


File: python.info,  Node: Core and Builtins<104>,  Next: Library<106>,  Prev: Security<31>,  Up: Python 3 10 0 alpha 3

1.23.49.2 Core and Builtins
...........................

   - bpo-42576(1): ‘types.GenericAlias’ will now raise a ‘TypeError’
     when attempting to initialize with a keyword argument.  Previously,
     this would cause the interpreter to crash if the interpreter was
     compiled with debug symbols.  This does not affect interpreters
     compiled for release.  Patch by Ken Jin.

   - bpo-42536(2): Several built-in and standard library types now
     ensure that their internal result tuples are always tracked by the
     *note garbage collector: 1a83.:

        - *note collections.OrderedDict.items(): 5de.

        - *note dict.items(): 7d3.

        - *note enumerate(): 14d0.

        - *note functools.reduce(): 1324.

        - *note itertools.combinations(): 135b.

        - *note itertools.combinations_with_replacement(): 12c8.

        - *note itertools.permutations(): 1a84.

        - *note itertools.product(): 135c.

        - *note itertools.zip_longest(): 12e5.

        - *note zip(): 7d4.

     Previously, they could have become untracked by a prior garbage
     collection.  Patch by Brandt Bucher.

   - bpo-42500(3): Improve handling of exceptions near recursion limit.
     Converts a number of Fatal Errors in RecursionErrors.

   - bpo-42246(4): PEP 626: After a return, the f_lineno attribute of a
     frame is always the last line executed.

   - bpo-42435(5): Speed up comparison of bytes objects with non-bytes
     objects when option *note -b: 5e6. is specified.  Speed up
     comparison of bytarray objects with non-buffer object.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42576

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42536

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42500

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42246

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42435


File: python.info,  Node: Library<106>,  Next: Core and Builtins<105>,  Prev: Core and Builtins<104>,  Up: Python 3 10 0 alpha 3

1.23.49.3 Library
.................

   - bpo-1635741(1): Port the ‘_warnings’ extension module to the
     multi-phase initialization API ( PEP 489(2)).  Patch by Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<105>,  Next: Library<107>,  Prev: Library<106>,  Up: Python 3 10 0 alpha 3

1.23.49.4 Core and Builtins
...........................

   - bpo-41686(1): On Windows, the ‘SIGINT’ event,
     ‘_PyOS_SigintEvent()’, is now created even if Python is configured
     to not install signal handlers (if *note
     PyConfig.install_signal_handlers: 8c6. equals to 0, or
     ‘Py_InitializeEx(0)’).

   - bpo-42381(2): Allow assignment expressions in set literals and set
     comprehensions as per PEP 572.  Patch by Pablo Galindo.

   - bpo-42202(3): Change function parameters annotations internal
     representation to tuple of strings.  Patch provided by Yurii
     Karabas.

   - bpo-42374(4): Fix a regression introduced by the new parser, where
     an unparenthesized walrus operator was not allowed within generator
     expressions.

   - bpo-42316(5): Allow an unparenthesized walrus in subscript indexes.

   - bpo-42349(6): Make sure that the compiler front-end produces a
     well-formed control flow graph.  Be more aggressive in the compiler
     back-end, as it is now safe to do so.

   - bpo-42296(7): On Windows, fix a regression in signal handling which
     prevented to interrupt a program using CTRL+C. The signal handler
     can be run in a thread different than the Python thread, in which
     case the test deciding if the thread can handle signals is wrong.

   - bpo-42332(8): *note types.GenericAlias: 7f0. objects can now be the
     targets of weakrefs.

   - bpo-42282(9): Optimise constant subexpressions that appear as part
     of named expressions (previously the AST optimiser did not descend
     into named expressions).  Patch by Nick Coghlan.

   - bpo-42266(10): Fixed a bug with the LOAD_ATTR opcode cache that was
     not respecting monkey-patching a class-level attribute to make it a
     descriptor.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41686

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42381

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42202

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42374

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42316

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42349

   (7) https://bugs.python.org/issue?@action=redirect&bpo=42296

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42332

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42282

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42266


File: python.info,  Node: Library<107>,  Next: Core and Builtins<106>,  Prev: Core and Builtins<105>,  Up: Python 3 10 0 alpha 3

1.23.49.5 Library
.................

   - bpo-40077(1): Convert *note queue: b6. to use heap types.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40077


File: python.info,  Node: Core and Builtins<106>,  Next: Library<108>,  Prev: Library<107>,  Up: Python 3 10 0 alpha 3

1.23.49.6 Core and Builtins
...........................

   - bpo-42246(1): Improved accuracy of line tracing events and f_lineno
     attribute of Frame objects.  See PEP 626 for details.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42246


File: python.info,  Node: Library<108>,  Next: Core and Builtins<107>,  Prev: Core and Builtins<106>,  Up: Python 3 10 0 alpha 3

1.23.49.7 Library
.................

   - bpo-40077(1): Convert *note mmap: 90. to use heap types.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40077


File: python.info,  Node: Core and Builtins<107>,  Next: Library<109>,  Prev: Library<108>,  Up: Python 3 10 0 alpha 3

1.23.49.8 Core and Builtins
...........................

   - bpo-42233(1): Allow ‘GenericAlias’ objects to use *note union type
     expressions: 7c6.  This allows expressions like ‘list[int] |
     dict[float, str]’ where previously a ‘TypeError’ would have been
     thrown.  This also fixes union type expressions not de-duplicating
     ‘GenericAlias’ objects.  (Contributed by Ken Jin in bpo-42233(2).)

   - bpo-26131(3): The import system triggers a ‘ImportWarning’ when it
     falls back to using ‘load_module()’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42233

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42233

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26131


File: python.info,  Node: Library<109>,  Next: Documentation<40>,  Prev: Core and Builtins<107>,  Up: Python 3 10 0 alpha 3

1.23.49.9 Library
.................

   - bpo-5054(1): CGIHTTPRequestHandler.run_cgi() HTTP_ACCEPT improperly
     parsed.  Replace the special purpose getallmatchingheaders with
     generic get_all method and add relevant tests.

     Original Patch by Martin Panter.  Modified by Senthil Kumaran.

   - bpo-42562(2): Fix issue when dis failed to parse function that has
     no line numbers.  Patch provided by Yurii Karabas.

   - bpo-17735(3): ‘inspect.findsource()’ now raises *note OSError: 41a.
     instead of *note IndexError: 1585. when ‘co_lineno’ of a code
     object is greater than the file length.  This can happen, for
     example, when a file is edited after it was imported.  PR by Irit
     Katriel.

   - bpo-42116(4): Fix handling of trailing comments by *note
     inspect.getsource(): 1619.

   - bpo-42532(5): Remove unexpected call of ‘__bool__’ when passing a
     ‘spec_arg’ argument to a Mock.

   - bpo-38200(6): Added itertools.pairwise()

   - bpo-41818(7): Fix test_master_read() so that it succeeds on all
     platforms that either raise OSError or return b”” upon reading from
     master.

   - bpo-42487(8): ChainMap.__iter__ no longer calls __getitem__ on
     underlying maps

   - bpo-42482(9): *note TracebackException: 25c. no longer holds a
     reference to the exception’s traceback object.  Consequently,
     instances of TracebackException for equivalent but non-equal
     exceptions now compare as equal.

   - bpo-41818(10): Make test_openpty() avoid unexpected success due to
     number of rows and/or number of columns being == 0.

   - bpo-42392(11): Remove loop parameter from ‘asyncio.subprocess’ and
     ‘asyncio.tasks’ functions.  Patch provided by Yurii Karabas.

   - bpo-42392(12): Remove loop parameter from ‘asyncio.open_connection’
     and ‘asyncio.start_server’ functions.  Patch provided by Yurii
     Karabas.

   - bpo-28468(13): Add *note platform.freedesktop_os_release(): 82c.
     function to parse freedesktop.org ‘os-release’ files.

   - bpo-42299(14): Removed the ‘formatter’ module, which was deprecated
     in Python 3.4.  It is somewhat obsolete, little used, and not
     tested.  It was originally scheduled to be removed in Python 3.6,
     but such removals were delayed until after Python 2.7 EOL. Existing
     users should copy whatever classes they use into their code.  Patch
     by Donghee Na and and Terry J. Reedy.

   - bpo-26131(15): Deprecate zipimport.zipimporter.load_module() in
     favour of exec_module().

   - bpo-41818(16): Updated tests for the pty library.  test_basic() has
     been changed to test_openpty(); this additionally checks if slave
     termios and slave winsize are being set properly by pty.openpty().
     In order to add support for FreeBSD, NetBSD, OpenBSD, and Darwin,
     this also adds test_master_read(), which demonstrates that
     pty.spawn() should not depend on an OSError to exit from its copy
     loop.

   - bpo-42392(17): Remove loop parameter from ‘__init__’ in all
     ‘asyncio.locks’ and ‘asyncio.Queue’ classes.  Patch provided by
     Yurii Karabas.

   - bpo-15450(18): Make *note filecmp.dircmp: f78. respect subclassing.
     Now the *note filecmp.dircmp.subdirs: 1a8c. behaves as expected
     when subclassing dircmp.

   - bpo-42413(19): The exception *note socket.timeout: 83a. is now an
     alias of *note TimeoutError: 83b.

   - bpo-31904(20): Support signal module on VxWorks.

   - bpo-42406(21): We fixed an issue in ‘pickle.whichmodule’ in which
     importing ‘multiprocessing’ could change the how pickle identifies
     which module an object belongs to, potentially breaking the
     unpickling of those objects.

   - bpo-42403(22): Simplify the *note importlib: 77. external bootstrap
     code: ‘importlib._bootstrap_external’ now uses regular imports to
     import builtin modules.  When it is imported, the builtin *note
     __import__(): 8dd. function is already fully working and so can be
     used to import builtin modules like *note sys: d9.  Patch by Victor
     Stinner.

   - bpo-1635741(23): Convert _sre module types to heap types (PEP 384).
     Patch by Erlend E. Aasland.

   - bpo-42375(24): subprocess module update for DragonFlyBSD support.

   - bpo-41713(25): Port the ‘_signal’ extension module to the
     multi-phase initialization API ( PEP 489(26)).  Patch by Victor
     Stinner and Mohamed Koubaa.

   - bpo-37205(27): *note time.time(): 254, *note time.perf_counter():
     a97. and *note time.monotonic(): 253. functions can no longer fail
     with a Python fatal error, instead raise a regular Python exception
     on failure.

   - bpo-42328(28): Fixed *note tkinter.ttk.Style.map(): 1a8d.  The
     function accepts now the representation of the default state as
     empty sequence (as returned by ‘Style.map()’).  The structure of
     the result is now the same on all platform and does not depend on
     the value of ‘wantobjects’.

   - bpo-42345(29): Fix various issues with ‘typing.Literal’ parameter
     handling (flatten, deduplicate, use type to cache key).  Patch
     provided by Yurii Karabas.

   - bpo-37205(30): *note time.perf_counter(): a97. on Windows and *note
     time.monotonic(): 253. on macOS are now system-wide.  Previously,
     they used an offset computed at startup to reduce the precision
     loss caused by the float type.  Use *note time.perf_counter_ns():
     afd. and *note time.monotonic_ns(): afc. added in Python 3.7 to
     avoid this precision loss.

   - bpo-42318(31): Fixed support of non-BMP characters in *note
     tkinter: f0. on macOS.

   - bpo-42350(32): Fix the *note threading.Thread: 956. class at fork:
     do nothing if the thread is already stopped (ex: fork called at
     Python exit).  Previously, an error was logged in the child
     process.

   - bpo-42333(33): Port _ssl extension module to heap types.

   - bpo-42014(34): The ‘onerror’ callback from ‘shutil.rmtree’ now
     receives correct function when ‘os.open’ fails.

   - bpo-42237(35): Fix ‘os.sendfile()’ on illumos.

   - bpo-42308(36): Add *note threading.__excepthook__: 850. to allow
     retrieving the original value of *note threading.excepthook(): 851.
     in case it is set to a broken or a different value.  Patch by Mario
     Corchero.

   - bpo-42131(37): Implement PEP 451/spec methods on
     zipimport.zipimporter: find_spec(), create_module(), and
     exec_module().

     This also allows for the documented deprecation of find_loader(),
     find_module(), and load_module().

   - bpo-41877(38): Mock objects which are not unsafe will now raise an
     AttributeError if an attribute with the prefix asert, aseert, or
     assrt is accessed, in addition to this already happening for the
     prefixes assert or assret.

   - bpo-42264(39): ‘sqlite3.OptimizedUnicode’ has been undocumented and
     obsolete since Python 3.3, when it was made an alias to *note str:
     44f.  It is now deprecated, scheduled for removal in Python 3.12.

   - bpo-42251(40): Added *note threading.gettrace(): 84c. and *note
     threading.getprofile(): 84d. to retrieve the functions set by *note
     threading.settrace(): 84e. and *note threading.setprofile(): 84f.
     respectively.  Patch by Mario Corchero.

   - bpo-42249(41): Fixed writing binary Plist files larger than 4 GiB.

   - bpo-42236(42): On Unix, the *note os.device_encoding(): 19db.
     function now returns ‘'UTF-8'’ rather than the device encoding if
     the *note Python UTF-8 Mode: 659. is enabled.

   - bpo-41754(43): webbrowser: Ignore 'NotADirectoryError' when calling
     ‘xdg-settings’.

   - bpo-42183(44): Fix a stack overflow error for asyncio Task or
     Future repr().

     The overflow occurs under some circumstances when a Task or Future
     recursively returns itself.

   - bpo-42140(45): Improve asyncio.wait function to create the futures
     set just one time.

   - bpo-42133(46): Update various modules in the stdlib to fall back on
     ‘__spec__.loader’ when ‘__loader__’ isn’t defined on a module.

   - bpo-26131(47): The ‘load_module()’ methods found in ‘importlib’ now
     trigger a ‘DeprecationWarning’.

   - bpo-39825(48): Windows: Change
     ‘sysconfig.get_config_var('EXT_SUFFIX')’ to the expected full
     ‘platform_tag.extension’ format.  Previously it was hard-coded to
     ‘.pyd’, now it is compatible with ‘distutils.sysconfig’ and will
     result in something like ‘.cp38-win_amd64.pyd’.  This brings
     windows into conformance with the other platforms.

   - bpo-26389(49): The *note traceback.format_exception(): 853, *note
     traceback.format_exception_only(): 854, and *note
     traceback.print_exception(): 855. functions can now take an
     exception object as a positional-only argument.

   - bpo-41889(50): Enum: fix regression involving inheriting a multiply
     inherited enum

   - bpo-41861(51): Convert *note sqlite3: cf. to use heap types (PEP
     384).  Patch by Erlend E. Aasland.

   - bpo-40624(52): Added support for the XPath ‘!=’ operator in
     xml.etree

   - bpo-28850(53): Fix *note pprint.PrettyPrinter.format(): 1a8e.
     overrides being ignored for contents of small containers.  The
     ‘pprint._safe_repr()’ function was removed.

   - bpo-41625(54): Expose the ‘splice()’ as *note os.splice(): 81f. in
     the *note os: a1. module.  Patch by Pablo Galindo

   - bpo-34215(55): Clarify the error message for *note
     asyncio.IncompleteReadError: 1a8f. when ‘expected’ is ‘None’.

   - bpo-41543(56): Add async context manager support for
     contextlib.nullcontext.

   - bpo-21041(57): *note pathlib.PurePath.parents: 826. now supports
     negative indexing.  Patch contributed by Yaroslav Pankovych.

   - bpo-41332(58): Added missing connect_accepted_socket() method to
     ‘asyncio.AbstractEventLoop’.

   - bpo-12800(59): Extracting a symlink from a tarball should succeed
     and overwrite the symlink if it already exists.  The fix is to
     remove the existing file or symlink before extraction.  Based on
     patch by Chris AtLee, Jeffrey Kintscher, and Senthil Kumaran.

   - bpo-40968(60): *note urllib.request: 10b. and *note http.client:
     6f. now send ‘http/1.1’ ALPN extension during TLS handshake when no
     custom context is supplied.

   - bpo-41001(61): Add *note os.eventfd(): 81e. to provide a low level
     interface for Linux’s event notification file descriptor.

   - bpo-40816(62): Add AsyncContextDecorator to contextlib to support
     async context manager as a decorator.

   - bpo-40550(63): Fix time-of-check/time-of-action issue in
     subprocess.Popen.send_signal.

   - bpo-39411(64): Add an ‘is_async’ identifier to *note pyclbr: b4.’s
     ‘Function’ objects.  Patch by Batuhan Taskaya

   - bpo-35498(65): Add slice support to *note pathlib.PurePath.parents:
     826.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5054

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42562

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17735

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42116

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42532

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38200

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41818

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42487

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42482

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41818

   (11) https://bugs.python.org/issue?@action=redirect&bpo=42392

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42392

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28468

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42299

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26131

   (16) https://bugs.python.org/issue?@action=redirect&bpo=41818

   (17) https://bugs.python.org/issue?@action=redirect&bpo=42392

   (18) https://bugs.python.org/issue?@action=redirect&bpo=15450

   (19) https://bugs.python.org/issue?@action=redirect&bpo=42413

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (21) https://bugs.python.org/issue?@action=redirect&bpo=42406

   (22) https://bugs.python.org/issue?@action=redirect&bpo=42403

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (24) https://bugs.python.org/issue?@action=redirect&bpo=42375

   (25) https://bugs.python.org/issue?@action=redirect&bpo=41713

   (26) https://peps.python.org/pep-0489/

   (27) https://bugs.python.org/issue?@action=redirect&bpo=37205

   (28) https://bugs.python.org/issue?@action=redirect&bpo=42328

   (29) https://bugs.python.org/issue?@action=redirect&bpo=42345

   (30) https://bugs.python.org/issue?@action=redirect&bpo=37205

   (31) https://bugs.python.org/issue?@action=redirect&bpo=42318

   (32) https://bugs.python.org/issue?@action=redirect&bpo=42350

   (33) https://bugs.python.org/issue?@action=redirect&bpo=42333

   (34) https://bugs.python.org/issue?@action=redirect&bpo=42014

   (35) https://bugs.python.org/issue?@action=redirect&bpo=42237

   (36) https://bugs.python.org/issue?@action=redirect&bpo=42308

   (37) https://bugs.python.org/issue?@action=redirect&bpo=42131

   (38) https://bugs.python.org/issue?@action=redirect&bpo=41877

   (39) https://bugs.python.org/issue?@action=redirect&bpo=42264

   (40) https://bugs.python.org/issue?@action=redirect&bpo=42251

   (41) https://bugs.python.org/issue?@action=redirect&bpo=42249

   (42) https://bugs.python.org/issue?@action=redirect&bpo=42236

   (43) https://bugs.python.org/issue?@action=redirect&bpo=41754

   (44) https://bugs.python.org/issue?@action=redirect&bpo=42183

   (45) https://bugs.python.org/issue?@action=redirect&bpo=42140

   (46) https://bugs.python.org/issue?@action=redirect&bpo=42133

   (47) https://bugs.python.org/issue?@action=redirect&bpo=26131

   (48) https://bugs.python.org/issue?@action=redirect&bpo=39825

   (49) https://bugs.python.org/issue?@action=redirect&bpo=26389

   (50) https://bugs.python.org/issue?@action=redirect&bpo=41889

   (51) https://bugs.python.org/issue?@action=redirect&bpo=41861

   (52) https://bugs.python.org/issue?@action=redirect&bpo=40624

   (53) https://bugs.python.org/issue?@action=redirect&bpo=28850

   (54) https://bugs.python.org/issue?@action=redirect&bpo=41625

   (55) https://bugs.python.org/issue?@action=redirect&bpo=34215

   (56) https://bugs.python.org/issue?@action=redirect&bpo=41543

   (57) https://bugs.python.org/issue?@action=redirect&bpo=21041

   (58) https://bugs.python.org/issue?@action=redirect&bpo=41332

   (59) https://bugs.python.org/issue?@action=redirect&bpo=12800

   (60) https://bugs.python.org/issue?@action=redirect&bpo=40968

   (61) https://bugs.python.org/issue?@action=redirect&bpo=41001

   (62) https://bugs.python.org/issue?@action=redirect&bpo=40816

   (63) https://bugs.python.org/issue?@action=redirect&bpo=40550

   (64) https://bugs.python.org/issue?@action=redirect&bpo=39411

   (65) https://bugs.python.org/issue?@action=redirect&bpo=35498


File: python.info,  Node: Documentation<40>,  Next: Tests<43>,  Prev: Library<109>,  Up: Python 3 10 0 alpha 3

1.23.49.10 Documentation
........................

   - bpo-42238(1): Tentative to deprecate ‘make suspicious’ by first
     removing it from the CI and documentation builds, but keeping it
     around for manual uses.

   - bpo-42153(2): Fix the URL for the IMAP protocol documents.

   - bpo-41028(3): Language and version switchers, previously maintained
     in every cpython branches, are now handled by docsbuild-script.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42238

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42153

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41028


File: python.info,  Node: Tests<43>,  Next: Build<47>,  Prev: Documentation<40>,  Up: Python 3 10 0 alpha 3

1.23.49.11 Tests
................

   - bpo-41473(1): Re-enable test_gdb on gdb 9.2 and newer:
     ‘https://bugzilla.redhat.com/show_bug.cgi?id=1866884’ bug is fixed
     in gdb 10.1.

   - bpo-42553(2): Fix ‘test_asyncio.test_call_later()’ race condition:
     don’t measure asyncio performance in the ‘call_later()’ unit test.
     The test failed randomly on the CI.

   - bpo-31904(3): Fix test_netrc on VxWorks: create temporary
     directories using temp_cwd().

   - bpo-31904(4): skip test_getaddrinfo_ipv6_scopeid_symbolic and
     test_getnameinfo_ipv6_scopeid_symbolic on VxWorks

   - bpo-31904(5): skip test_test of test_mailcap on VxWorks

   - bpo-31904(6): add shell requirement for test_pipes

   - bpo-31904(7): skip some tests related to fifo on VxWorks

   - bpo-31904(8): Fix test_doctest.py failures for VxWorks.

   - bpo-40754(9): Include ‘_testinternalcapi’ module in Windows
     installer for test suite

   - bpo-41561(10): test_ssl: skip test_min_max_version_mismatch when
     TLS 1.0 is not available

   - bpo-31904(11): Fix os module failures for VxWorks RTOS.

   - bpo-31904(12): Fix fifo test cases for VxWorks RTOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41473

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42553

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40754

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41561

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31904


File: python.info,  Node: Build<47>,  Next: Windows<40>,  Prev: Tests<43>,  Up: Python 3 10 0 alpha 3

1.23.49.12 Build
................

   - bpo-31904(1): remove libnet dependency from detect_socket() for
     VxWorks

   - bpo-42398(2): Fix a race condition in “make regen-all” when make
     -jN option is used to run jobs in parallel.  The clinic.py script
     now only use atomic write to write files.  Moveover, generated
     files are now left unchanged if the content does not change, to not
     change the file modification time.

   - bpo-41617(3): Fix building ‘pycore_bitutils.h’ internal header on
     old clang version without ‘__builtin_bswap16()’ (ex: Xcode 4.6.3 on
     Mac OS X 10.7).  Patch by Joshua Root and Victor Stinner.

   - bpo-38823(4): It is no longer possible to build the ‘_ctypes’
     extension module without ‘wchar_t’ type: remove ‘CTYPES_UNICODE’
     macro.  Anyway, the ‘wchar_t’ type is required to build Python.
     Patch by Victor Stinner.

   - bpo-42087(5): Support was removed for AIX 5.3 and below.  See
     bpo-40680(6).

   - bpo-40998(7): Addressed three compiler warnings found by undefined
     behavior sanitizer (ubsan).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42398

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41617

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38823

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42087

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40680

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40998


File: python.info,  Node: Windows<40>,  Next: macOS<32>,  Prev: Build<47>,  Up: Python 3 10 0 alpha 3

1.23.49.13 Windows
..................

   - bpo-42120(1): Remove macro definition of ‘copysign’ (to
     ‘_copysign’) in headers.

   - bpo-38506(2): The Windows launcher now properly handles Python 3.10
     when listing installed Python versions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42120

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38506


File: python.info,  Node: macOS<32>,  Next: IDLE<28>,  Prev: Windows<40>,  Up: Python 3 10 0 alpha 3

1.23.49.14 macOS
................

   - bpo-42504(1): Fix build on macOS Big Sur when
     MACOSX_DEPLOYMENT_TARGET=11

   - bpo-41116(2): Ensure distutils.unixxcompiler.find_library_file can
     find system provided libraries on macOS 11.

   - bpo-41100(3): Add support for macOS 11 and Apple Silicon systems.

     It is now possible to build “Universal 2” binaries using
     “–enable-universalsdk –with-universal-archs=universal2”.

     Binaries build on later macOS versions can be deployed back to
     older versions (tested up to macOS 10.9), when using the correct
     deployment target.  This is tested using Xcode 11 and later.

   - bpo-42232(4): Added Darwin specific madvise options to mmap module.

   - bpo-38443(5): The ‘--enable-universalsdk’ and
     ‘--with-universal-archs’ options for the configure script now check
     that the specified architectures can be used.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42504

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41116

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41100

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42232

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38443


File: python.info,  Node: IDLE<28>,  Next: Tools/Demos<22>,  Prev: macOS<32>,  Up: Python 3 10 0 alpha 3

1.23.49.15 IDLE
...............

   - bpo-42508(1): Keep IDLE running on macOS. Remove obsolete
     workaround that prevented running files with shortcuts when using
     new universal2 installers built on macOS 11.

   - bpo-42426(2): Fix reporting offset of the RE error in searchengine.

   - bpo-42415(3): Get docstrings for IDLE calltips more often by using
     inspect.getdoc.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42508

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42426

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42415


File: python.info,  Node: Tools/Demos<22>,  Next: C API<42>,  Prev: IDLE<28>,  Up: Python 3 10 0 alpha 3

1.23.49.16 Tools/Demos
......................

   - bpo-42212(1): The smelly.py script now also checks the Python
     dynamic library and extension modules, not only the Python static
     library.  Make also the script more verbose: explain what it does.

   - bpo-36310(2): Allow ‘Tools/i18n/pygettext.py’ to detect calls to
     ‘gettext’ in f-strings.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42212

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36310


File: python.info,  Node: C API<42>,  Prev: Tools/Demos<22>,  Up: Python 3 10 0 alpha 3

1.23.49.17 C API
................

   - bpo-42423(1): The *note PyType_FromSpecWithBases(): 581. and *note
     PyType_FromModuleAndSpec(): 554. functions now accept a single
     class as the 'bases' argument.

   - bpo-1635741(2): Port *note select: c1. extension module to
     multiphase initialization ( PEP 489(3)).

   - bpo-1635741(4): Port _posixsubprocess extension module to
     multiphase initialization ( PEP 489(5)).

   - bpo-1635741(6): Port _posixshmem extension module to multiphase
     initialization ( PEP 489(7))

   - bpo-1635741(8): Port _struct extension module to multiphase
     initialization ( PEP 489(9))

   - bpo-1635741(10): Port ‘spwd’ extension module to multiphase
     initialization ( PEP 489(11))

   - bpo-1635741(12): Port *note gc: 60. extension module to multiphase
     initialization ( PEP 489(13))

   - bpo-1635741(14): Port _queue extension module to multiphase
     initialization ( PEP 489(15))

   - bpo-39573(16): Convert *note Py_TYPE(): 783. and *note Py_SIZE():
     785. back to macros to allow using them as an l-value.  Many third
     party C extension modules rely on the ability of using Py_TYPE()
     and Py_SIZE() to set an object type and size: ‘Py_TYPE(obj) =
     type;’ and ‘Py_SIZE(obj) = size;’.

   - bpo-1635741(17): Port *note symtable: d8. extension module to
     multiphase initialization ( PEP 489(18))

   - bpo-1635741(19): Port *note grp: 66. and *note pwd: b2. extension
     modules to multiphase initialization ( PEP 489(20))

   - bpo-1635741(21): Port _random extension module to multiphase
     initialization ( PEP 489(22))

   - bpo-1635741(23): Port _hashlib extension module to multiphase
     initialization ( PEP 489(24))

   - bpo-41713(25): Removed the undocumented ‘PyOS_InitInterrupts()’
     function.  Initializing Python already implicitly installs signal
     handlers: see *note PyConfig.install_signal_handlers: 8c6.  Patch
     by Victor Stinner.

   - bpo-40170(26): The ‘Py_TRASHCAN_BEGIN’ macro no longer accesses
     PyTypeObject attributes, but now can get the condition by calling
     the new private ‘_PyTrash_cond()’ function which hides
     implementation details.

   - bpo-42260(27): *note Py_GetPath(): 3b6, *note Py_GetPrefix(): 3b8,
     *note Py_GetExecPrefix(): 3b4, *note Py_GetProgramFullPath(): 3ba,
     *note Py_GetPythonHome(): 3bd. and *note Py_GetProgramName(): 3bc.
     functions now return ‘NULL’ if called before *note Py_Initialize():
     8b4. (before Python is initialized).  Use the new *note Python
     Initialization Configuration API: 3aa. to get the *note Python Path
     Configuration.: 8b5.  Patch by Victor Stinner.

   - bpo-42260(28): The *note PyConfig_Read(): 793. function now only
     parses *note PyConfig.argv: 3c6. arguments once: *note
     PyConfig.parse_argv: 1a98. is set to ‘2’ after arguments are
     parsed.  Since Python arguments are strippped from ‘PyConfig.argv’,
     parsing arguments twice would parse the application options as
     Python options.

   - bpo-42262(29): Added *note Py_NewRef(): 8a1. and *note
     Py_XNewRef(): 8a2. functions to increment the reference count of an
     object and return the object.  Patch by Victor Stinner.

   - bpo-42260(30): When *note Py_Initialize(): 8b4. is called twice,
     the second call now updates more *note sys: d9. attributes for the
     configuration, rather than only *note sys.argv: 12ab.  Patch by
     Victor Stinner.

   - bpo-41832(31): The *note PyType_FromModuleAndSpec(): 554. function
     now accepts NULL ‘tp_doc’ slot.

   - bpo-1635741(32): Added *note PyModule_AddObjectRef(): 368.
     function: similar to *note PyModule_AddObject(): 369. but don’t
     steal a reference to the value on success.  Patch by Victor
     Stinner.

   - bpo-42171(33): The *note METH_FASTCALL: 1731. calling convention is
     added to the limited API. The functions *note PyModule_AddType():
     97f, *note PyType_FromModuleAndSpec(): 554, *note
     PyType_GetModule(): 978. and *note PyType_GetModuleState(): 979.
     are added to the limited API on Windows.

   - bpo-42085(34): Add dedicated entry to PyAsyncMethods for sending
     values

   - bpo-41073(35): *note PyType_GetSlot(): 8a3. can now accept static
     types.

   - bpo-30459(36): *note PyList_SET_ITEM(): 391, *note
     PyTuple_SET_ITEM(): 390. and *note PyCell_SET(): 8b6. macros can no
     longer be used as l-value or r-value.  For example, ‘x =
     PyList_SET_ITEM(a, b, c)’ and ‘PyList_SET_ITEM(a, b, c) = x’ now
     fail with a compiler error.  It prevents bugs like ‘if
     (PyList_SET_ITEM (a, b, c) < 0) ...’ test.  Patch by Zackery Spytz
     and Victor Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42423

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (3) https://peps.python.org/pep-0489/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (5) https://peps.python.org/pep-0489/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (7) https://peps.python.org/pep-0489/

   (8) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (9) https://peps.python.org/pep-0489/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (11) https://peps.python.org/pep-0489/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (13) https://peps.python.org/pep-0489/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (15) https://peps.python.org/pep-0489/

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (17) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (18) https://peps.python.org/pep-0489/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (20) https://peps.python.org/pep-0489/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (22) https://peps.python.org/pep-0489/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (24) https://peps.python.org/pep-0489/

   (25) https://bugs.python.org/issue?@action=redirect&bpo=41713

   (26) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (27) https://bugs.python.org/issue?@action=redirect&bpo=42260

   (28) https://bugs.python.org/issue?@action=redirect&bpo=42260

   (29) https://bugs.python.org/issue?@action=redirect&bpo=42262

   (30) https://bugs.python.org/issue?@action=redirect&bpo=42260

   (31) https://bugs.python.org/issue?@action=redirect&bpo=41832

   (32) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (33) https://bugs.python.org/issue?@action=redirect&bpo=42171

   (34) https://bugs.python.org/issue?@action=redirect&bpo=42085

   (35) https://bugs.python.org/issue?@action=redirect&bpo=41073

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30459


File: python.info,  Node: Python 3 10 0 alpha 2,  Next: Python 3 10 0 alpha 1,  Prev: Python 3 10 0 alpha 3,  Up: Changelog

1.23.50 Python 3.10.0 alpha 2
-----------------------------

'Release date: 2020-11-03'

* Menu:

* Security: Security<32>.
* Core and Builtins: Core and Builtins<108>.
* Library: Library<110>.
* Core and Builtins: Core and Builtins<109>.
* Library: Library<111>.
* Documentation: Documentation<41>.
* Tests: Tests<44>.
* Build: Build<48>.
* Windows: Windows<41>.
* macOS: macOS<33>.
* IDLE: IDLE<29>.
* C API: C API<43>.


File: python.info,  Node: Security<32>,  Next: Core and Builtins<108>,  Up: Python 3 10 0 alpha 2

1.23.50.1 Security
..................

   - bpo-42103(1): Prevented potential DoS attack via CPU and RAM
     exhaustion when processing malformed Apple Property List files in
     binary format.

   - bpo-42051(2): The *note plistlib: ab. module no longer accepts
     entity declarations in XML plist files to avoid XML
     vulnerabilities.  This should not affect users as entity
     declarations are not used in regular plist files.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42103

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42051


File: python.info,  Node: Core and Builtins<108>,  Next: Library<110>,  Prev: Security<32>,  Up: Python 3 10 0 alpha 2

1.23.50.2 Core and Builtins
...........................

   - bpo-42236(1): If the ‘nl_langinfo(CODESET)’ function returns an
     empty string, Python now uses UTF-8 as the filesystem encoding.
     Patch by Victor Stinner.

   - bpo-42218(2): Fixed a bug in the PEG parser that was causing
     crashes in debug mode.  Now errors are checked in left-recursive
     rules to avoid cases where such errors do not get handled in time
     and appear as long-distance crashes in other places.

   - bpo-42214(3): Fixed a possible crash in the PEG parser when
     checking for the ‘!=’ token in the ‘barry_as_flufl’ rule.  Patch by
     Pablo Galindo.

   - bpo-42206(4): Propagate and raise the errors caused by
     ‘PyAST_Validate()’ in the parser.

   - bpo-41796(5): The *note ast: 8. module internal state is now per
     interpreter.  Patch by Victor Stinner.

   - bpo-42143(6): Fix handling of errors during creation of
     ‘PyFunctionObject’, which resulted in operations on uninitialized
     memory.  Patch by Yonatan Goldschmidt.

   - bpo-41659(7): Fix a bug in the parser, where a curly brace
     following a ‘primary’ didn’t fail immediately.  This led to invalid
     expressions like ‘a {b}’ to throw a *note SyntaxError: 18d. with a
     wrong offset, or invalid expressions ending with a curly brace like
     ‘a {’ to not fail immediately in the REPL.

   - bpo-42150(8): Fix possible buffer overflow in the new parser when
     checking for continuation lines.  Patch by Pablo Galindo.

   - bpo-42123(9): Run the parser two times.  On the first run, disable
     all the rules that only generate better error messages to gain
     performance.  If there’s a parse failure, run the parser a second
     time with those enabled.

   - bpo-42093(10): The ‘LOAD_ATTR’ instruction now uses new “per opcode
     cache” mechanism and it is about 36% faster now.  Patch by Pablo
     Galindo and Yury Selivanov.

   - bpo-42030(11): Support for the legacy AIX-specific shared library
     loading support has been removed.  All versions of AIX since 4.3
     have supported and defaulted to using the common Unix mechanism
     instead.

   - bpo-41984(12): The garbage collector now tracks all user-defined
     classes.  Patch by Brandt Bucher.

   - bpo-41993(13): Fixed potential issues with removing not completely
     initialized module from ‘sys.modules’ when import fails.

   - bpo-41979(14): Star-unpacking is now allowed for with item’s
     targets in the PEG parser.

   - bpo-41974(15): Removed special methods ‘__int__’, ‘__float__’,
     ‘__floordiv__’, ‘__mod__’, ‘__divmod__’, ‘__rfloordiv__’,
     ‘__rmod__’ and ‘__rdivmod__’ of the *note complex: 2f8. class.
     They always raised a *note TypeError: 2c3.

   - bpo-41902(16): Micro optimization when compute *note sq_item: 1a9c.
     and *note mp_subscript: 1a9d. of *note range: 94d.  Patch by
     Donghee Na.

   - bpo-41894(17): When loading a native module and a load failure
     occurs, prevent a possible UnicodeDecodeError when not running in a
     UTF-8 locale by decoding the load error message using the current
     locale’s encoding.

   - bpo-41902(18): Micro optimization for range.index if step is 1.
     Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42236

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42218

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42214

   (4) https://bugs.python.org/issue?@action=redirect&bpo=42206

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41796

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42143

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41659

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42150

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42123

   (10) https://bugs.python.org/issue?@action=redirect&bpo=42093

   (11) https://bugs.python.org/issue?@action=redirect&bpo=42030

   (12) https://bugs.python.org/issue?@action=redirect&bpo=41984

   (13) https://bugs.python.org/issue?@action=redirect&bpo=41993

   (14) https://bugs.python.org/issue?@action=redirect&bpo=41979

   (15) https://bugs.python.org/issue?@action=redirect&bpo=41974

   (16) https://bugs.python.org/issue?@action=redirect&bpo=41902

   (17) https://bugs.python.org/issue?@action=redirect&bpo=41894

   (18) https://bugs.python.org/issue?@action=redirect&bpo=41902


File: python.info,  Node: Library<110>,  Next: Core and Builtins<109>,  Prev: Core and Builtins<108>,  Up: Python 3 10 0 alpha 2

1.23.50.3 Library
.................

   - bpo-41435(1): Add ‘sys._current_exceptions()’ function to retrieve
     a dictionary mapping each thread’s identifier to the topmost
     exception currently active in that thread at the time the function
     is called.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41435


File: python.info,  Node: Core and Builtins<109>,  Next: Library<111>,  Prev: Library<110>,  Up: Python 3 10 0 alpha 2

1.23.50.4 Core and Builtins
...........................

   - bpo-38605(1): Enable ‘from __future__ import annotations’ ( PEP
     563(2)) by default.  The values found in ‘__annotations__’ dicts
     are now strings, for example ‘{"x": "int"}’ instead of ‘{"x":
     int}’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38605

   (2) https://peps.python.org/pep-0563/


File: python.info,  Node: Library<111>,  Next: Documentation<41>,  Prev: Core and Builtins<109>,  Up: Python 3 10 0 alpha 2

1.23.50.5 Library
.................

   - bpo-35455(1): On Solaris, *note thread_time(): 940. is now
     implemented with ‘gethrvtime()’ because
     ‘clock_gettime(CLOCK_THREAD_CPUTIME_ID)’ is not always available.
     Patch by Jakub Kulik.

   - bpo-42233(2): The *note repr(): 803. of *note typing: 104. types
     containing *note Generic Alias Types: 6b5. previously did not show
     the parameterized types in the ‘GenericAlias’.  They have now been
     changed to do so.

   - bpo-29566(3): ‘binhex.binhex()’ consistently writes macOS 9 line
     endings.

   - bpo-26789(4): The *note logging.FileHandler: 19f9. class now keeps
     a reference to the builtin *note open(): 51f. function to be able
     to open or reopen the file during Python finalization.  Fix errors
     like: ‘NameError: name 'open' is not defined’.  Patch by Victor
     Stinner.

   - bpo-42157(5): Removed the ‘unicodedata.ucnhash_CAPI’ attribute
     which was an internal PyCapsule object.  The related private
     ‘_PyUnicode_Name_CAPI’ structure was moved to the internal C API.
     Patch by Victor Stinner.

   - bpo-42157(6): Convert the *note unicodedata: 105. extension module
     to the multiphase initialization API ( PEP 489(7)) and convert the
     ‘unicodedata.UCD’ static type to a heap type.  Patch by Mohamed
     Koubaa and Victor Stinner.

   - bpo-42146(8): Fix memory leak in *note subprocess.Popen(): 199. in
     case an uid (gid) specified in ‘user’ (‘group’, ‘extra_groups’)
     overflows ‘uid_t’ (‘gid_t’).

   - bpo-42103(9): *note InvalidFileException: 1aa1. and *note
     RecursionError: d96. are now the only errors caused by loading
     malformed binary Plist file (previously ValueError and TypeError
     could be raised in some specific cases).

   - bpo-41490(10): In ‘importlib.resources’, ‘.path’ method is more
     aggressive about releasing handles to zipfile objects early,
     enabling use-cases like certifi to leave the context open but
     delete the underlying zip file.

   - bpo-41052(11): Pickling heap types implemented in C with protocols
     0 and 1 raises now an error instead of producing incorrect data.

   - bpo-42089(12): In ‘importlib.metadata.PackageNotFoundError’, make
     reference to the package metadata being missing to improve the user
     experience.

   - bpo-41491(13): plistlib: fix parsing XML plists with hexadecimal
     integer values

   - bpo-42065(14): Fix an incorrectly formatted error from
     ‘_codecs.charmap_decode()’ when called with a mapped value outside
     the range of valid Unicode code points.  PR by Max Bernstein.

   - bpo-41966(15): Fix pickling pure Python *note datetime.time: 1ce.
     subclasses.  Patch by Dean Inwood.

   - bpo-19270(16): *note sched.scheduler.cancel(): 1aa2. will now
     cancel the correct event, if two events with same priority are
     scheduled for the same time.  Patch by Bar Harel.

   - bpo-28660(17): *note textwrap.wrap(): 1516. now attempts to break
     long words after hyphens when ‘break_long_words=True’ and
     ‘break_on_hyphens=True’.

   - bpo-35823(18): Use ‘vfork()’ instead of ‘fork()’ for *note
     subprocess.Popen(): 199. on Linux to improve performance in cases
     where it is deemed safe.

   - bpo-42043(19): Add support for ‘zipfile.Path’ inheritance.
     ‘zipfile.Path.is_file()’ now returns False for non-existent names.
     ‘zipfile.Path’ objects now expose a ‘.filename’ attribute and rely
     on that to resolve ‘.name’ and ‘.parent’ when the ‘Path’ object is
     at the root of the zipfile.

   - bpo-42021(20): Fix possible ref leaks in *note sqlite3: cf. module
     init.

   - bpo-39101(21): Fixed tests using IsolatedAsyncioTestCase from
     hanging on BaseExceptions.

   - bpo-41976(22): Fixed a bug that was causing *note
     ctypes.util.find_library(): d72. to return ‘None’ when triying to
     locate a library in an environment when gcc>=9 is available and
     ‘ldconfig’ is not.  Patch by Pablo Galindo

   - bpo-41943(23): Fix bug where TestCase.assertLogs doesn’t correctly
     filter messages by level.

   - bpo-41923(24): Implement PEP 613(25), introducing *note
     typing.TypeAlias: 7cd. annotation.

   - bpo-41905(26): A new function in abc: 'update_abstractmethods' to
     re-calculate an abstract class’s abstract status.  In addition,
     'dataclass' has been changed to call this function.

   - bpo-23706(27): Added 'newline' parameter to
     ‘pathlib.Path.write_text()’.

   - bpo-41876(28): Tkinter font class repr uses font name

   - bpo-41831(29): ‘str()’ for the ‘type’ attribute of the
     ‘tkinter.Event’ object always returns now the numeric code returned
     by Tk instead of the name of the event type.

   - bpo-39337(30): *note encodings.normalize_encoding(): 801. now
     ignores non-ASCII characters.

   - bpo-41747(31): Ensure all methods that generated from *note
     dataclasses.dataclass(): 1cb. objects now have the proper
     ‘__qualname__’ attribute referring to the class they belong to.
     Patch by Batuhan Taskaya.

   - bpo-30681(32): Handle exceptions caused by unparsable date headers
     when using email “default” policy.  Patch by Tim Bell, Georges Toth

   - bpo-41586(33): Add F_SETPIPE_SZ and F_GETPIPE_SZ to fcntl module.
     Allow setting pipesize on subprocess.Popen.

   - bpo-41229(34): Add ‘contextlib.aclosing’ for deterministic cleanup
     of async generators which is analogous to ‘contextlib.closing’ for
     non-async generators.  Patch by Joongi Kim and John Belmonte.

   - bpo-16396(35): Allow ‘ctypes.wintypes’ to be imported on
     non-Windows systems.

   - bpo-4356(36): Add a key function to the bisect module.

   - bpo-40592(37): *note shutil.which(): 4b7. now ignores empty entries
     in ‘PATHEXT’ instead of treating them as a match.

   - bpo-40492(38): Fix ‘--outfile’ for *note cProfile: 27. / *note
     profile: af. not writing the output file in the original directory
     when the program being profiled changes the working directory.  PR
     by Anthony Sottile.

   - bpo-34204(39): The *note shelve: c3. module now uses *note
     pickle.DEFAULT_PROTOCOL: 834. by default instead of *note pickle:
     a6. protocol ‘3’.

   - bpo-27321(40): Fixed KeyError exception when flattening an email to
     a string attempts to replace a non-existent
     Content-Transfer-Encoding header.

   - bpo-38976(41): The *note http.cookiejar: 70. module now supports
     the parsing of cookies in CURL-style cookiejar files through
     MozillaCookieJar on all platforms.  Previously, such cookie entries
     would be silently ignored when loading a cookiejar with such
     entries.

     Additionally, the HTTP Only attribute is persisted in the object,
     and will be correctly written to file if the MozillaCookieJar
     object is subsequently dumped.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35455

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42233

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29566

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26789

   (5) https://bugs.python.org/issue?@action=redirect&bpo=42157

   (6) https://bugs.python.org/issue?@action=redirect&bpo=42157

   (7) https://peps.python.org/pep-0489/

   (8) https://bugs.python.org/issue?@action=redirect&bpo=42146

   (9) https://bugs.python.org/issue?@action=redirect&bpo=42103

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41490

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41052

   (12) https://bugs.python.org/issue?@action=redirect&bpo=42089

   (13) https://bugs.python.org/issue?@action=redirect&bpo=41491

   (14) https://bugs.python.org/issue?@action=redirect&bpo=42065

   (15) https://bugs.python.org/issue?@action=redirect&bpo=41966

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19270

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28660

   (18) https://bugs.python.org/issue?@action=redirect&bpo=35823

   (19) https://bugs.python.org/issue?@action=redirect&bpo=42043

   (20) https://bugs.python.org/issue?@action=redirect&bpo=42021

   (21) https://bugs.python.org/issue?@action=redirect&bpo=39101

   (22) https://bugs.python.org/issue?@action=redirect&bpo=41976

   (23) https://bugs.python.org/issue?@action=redirect&bpo=41943

   (24) https://bugs.python.org/issue?@action=redirect&bpo=41923

   (25) https://peps.python.org/pep-0613/

   (26) https://bugs.python.org/issue?@action=redirect&bpo=41905

   (27) https://bugs.python.org/issue?@action=redirect&bpo=23706

   (28) https://bugs.python.org/issue?@action=redirect&bpo=41876

   (29) https://bugs.python.org/issue?@action=redirect&bpo=41831

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39337

   (31) https://bugs.python.org/issue?@action=redirect&bpo=41747

   (32) https://bugs.python.org/issue?@action=redirect&bpo=30681

   (33) https://bugs.python.org/issue?@action=redirect&bpo=41586

   (34) https://bugs.python.org/issue?@action=redirect&bpo=41229

   (35) https://bugs.python.org/issue?@action=redirect&bpo=16396

   (36) https://bugs.python.org/issue?@action=redirect&bpo=4356

   (37) https://bugs.python.org/issue?@action=redirect&bpo=40592

   (38) https://bugs.python.org/issue?@action=redirect&bpo=40492

   (39) https://bugs.python.org/issue?@action=redirect&bpo=34204

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27321

   (41) https://bugs.python.org/issue?@action=redirect&bpo=38976


File: python.info,  Node: Documentation<41>,  Next: Tests<44>,  Prev: Library<111>,  Up: Python 3 10 0 alpha 2

1.23.50.6 Documentation
.......................

   - bpo-42061(1): Document __format__ functionality for IP addresses.

   - bpo-41910(2): Document the default implementation of
     ‘object.__eq__’.

   - bpo-42010(3): Clarify that subscription expressions are also valid
     for certain *note classes: 1aa4. and *note types: 1aa5. in the
     standard library, and for user-defined classes and types if the
     classmethod ‘__class_getitem__()’ is provided.

   - bpo-41805(4): Documented *note generic alias type: 6b5. and *note
     types.GenericAlias: 7f0.  Also added an entry in glossary for *note
     generic types: 43c.

   - bpo-39693(5): Fix tarfile’s extractfile documentation

   - bpo-39416(6): Document some restrictions on the default string
     representations of numeric classes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42061

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41910

   (3) https://bugs.python.org/issue?@action=redirect&bpo=42010

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41805

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39693

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39416


File: python.info,  Node: Tests<44>,  Next: Build<48>,  Prev: Documentation<41>,  Up: Python 3 10 0 alpha 2

1.23.50.7 Tests
...............

   - bpo-41739(1): Fix
     test_logging.test_race_between_set_target_and_flush(): the test now
     waits until all threads complete to avoid leaking running threads.

   - bpo-41970(2): Avoid a test failure in ‘test_lib2to3’ if the module
     has already imported at the time the test executes.  Patch by Pablo
     Galindo.

   - bpo-41944(3): Tests for CJK codecs no longer call ‘eval()’ on
     content received via HTTP.

   - bpo-41306(4): Fixed a failure in ‘test_tk.test_widgets.ScaleTest’
     happening when executing the test with Tk 8.6.10.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41739

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41970

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41944

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41306


File: python.info,  Node: Build<48>,  Next: Windows<41>,  Prev: Tests<44>,  Up: Python 3 10 0 alpha 2

1.23.50.8 Build
...............

   - bpo-38980(1): Add ‘-fno-semantic-interposition’ to both the compile
     and link line when building with ‘--enable-optimizations’.  Patch
     by Victor Stinner and Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38980


File: python.info,  Node: Windows<41>,  Next: macOS<33>,  Prev: Build<48>,  Up: Python 3 10 0 alpha 2

1.23.50.9 Windows
.................

   - bpo-38439(1): Updates the icons for IDLE in the Windows Store
     package.

   - bpo-38252(2): Use 8-byte step to detect ASCII sequence in 64-bit
     Windows build.

   - bpo-39107(3): Update Tcl and Tk to 8.6.10 in Windows installer.

   - bpo-41557(4): Update Windows installer to use SQLite 3.33.0.

   - bpo-38324(5): Avoid Unicode errors when accessing certain locale
     data on Windows.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38439

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38252

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39107

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41557

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38324


File: python.info,  Node: macOS<33>,  Next: IDLE<29>,  Prev: Windows<41>,  Up: Python 3 10 0 alpha 2

1.23.50.10 macOS
................

   - bpo-41471(1): Ignore invalid prefix lengths in system proxy
     excludes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41471


File: python.info,  Node: IDLE<29>,  Next: C API<43>,  Prev: macOS<33>,  Up: Python 3 10 0 alpha 2

1.23.50.11 IDLE
...............

   - bpo-33987(1): Mostly finish using ttk widgets, mainly for editor,
     settings, and searches.  Some patches by Mark Roseman.

   - bpo-40511(2): Typing opening and closing parentheses inside the
     parentheses of a function call will no longer cause unnecessary
     “flashing” off and on of an existing open call-tip, e.g.  when
     typed in a string literal.

   - bpo-38439(3): Add a 256×256 pixel IDLE icon to the Windows .ico
     file.  Created by Andrew Clover.  Remove the low-color gif
     variations from the .ico file.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33987

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40511

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38439


File: python.info,  Node: C API<43>,  Prev: IDLE<29>,  Up: Python 3 10 0 alpha 2

1.23.50.12 C API
................

   - bpo-42157(1): The private ‘_PyUnicode_Name_CAPI’ structure of the
     PyCapsule API ‘unicodedata.ucnhash_CAPI’ has been moved to the
     internal C API. Patch by Victor Stinner.

   - bpo-42015(2): Fix potential crash in deallocating method objects
     when dynamically allocated *note PyMethodDef: 1526.’s lifetime is
     managed through the ‘self’ argument of a *note PyCFunction: 14c7.

   - bpo-40423(3): The *note subprocess: d6. module and ‘os.closerange’
     will now use the ‘close_range(low, high, flags)’ syscall when it is
     available for more efficient closing of ranges of descriptors.

   - bpo-41845(4): *note PyObject_GenericGetDict(): 1aac. is available
     again in the limited API when targeting 3.10 or later.

   - bpo-40422(5): Add ‘_Py_closerange’ function to provide performant
     closing of a range of file descriptors.

   - bpo-41986(6): ‘Py_FileSystemDefaultEncodeErrors’ and ‘Py_UTF8Mode’
     are available again in limited API.

   - bpo-41756(7): Add ‘PyIter_Send’ function to allow sending value
     into generator/coroutine/iterator without raising StopIteration
     exception to signal return.

   - bpo-41784(8): Added ‘PyUnicode_AsUTF8AndSize’ to the limited C API.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42157

   (2) https://bugs.python.org/issue?@action=redirect&bpo=42015

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40423

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41845

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40422

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41986

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41756

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41784


File: python.info,  Node: Python 3 10 0 alpha 1,  Next: Python 3 9 0 beta 1,  Prev: Python 3 10 0 alpha 2,  Up: Changelog

1.23.51 Python 3.10.0 alpha 1
-----------------------------

'Release date: 2020-10-05'

* Menu:

* Security: Security<33>.
* Core and Builtins: Core and Builtins<110>.
* Library: Library<112>.
* Core and Builtins: Core and Builtins<111>.
* Library: Library<113>.
* Core and Builtins: Core and Builtins<112>.
* Library: Library<114>.
* Core and Builtins: Core and Builtins<113>.
* Library: Library<115>.
* Core and Builtins: Core and Builtins<114>.
* Library: Library<116>.
* Core and Builtins: Core and Builtins<115>.
* Library: Library<117>.
* Core and Builtins: Core and Builtins<116>.
* Library: Library<118>.
* Core and Builtins: Core and Builtins<117>.
* Library: Library<119>.
* Core and Builtins: Core and Builtins<118>.
* Library: Library<120>.
* Core and Builtins: Core and Builtins<119>.
* Library: Library<121>.
* Core and Builtins: Core and Builtins<120>.
* Library: Library<122>.
* Core and Builtins: Core and Builtins<121>.
* Library: Library<123>.
* Core and Builtins: Core and Builtins<122>.
* Library: Library<124>.
* Core and Builtins: Core and Builtins<123>.
* Library: Library<125>.
* Core and Builtins: Core and Builtins<124>.
* Library: Library<126>.
* Documentation: Documentation<42>.
* Tests: Tests<45>.
* Build: Build<49>.
* Windows: Windows<42>.
* macOS: macOS<34>.
* IDLE: IDLE<30>.
* C API: C API<44>.


File: python.info,  Node: Security<33>,  Next: Core and Builtins<110>,  Up: Python 3 10 0 alpha 1

1.23.51.1 Security
..................

   - bpo-41304(1): Fixes ‘python3x._pth’ being ignored on Windows,
     caused by the fix for bpo-29778(2) ( CVE 2020-15801(3)).

   - bpo-41162(4): Audit hooks are now cleared later during finalization
     to avoid missing events.

   - bpo-29778(5): Ensure ‘python3.dll’ is loaded from correct locations
     when Python is embedded ( CVE 2020-15523(6)).

   - bpo-41004(7): The __hash__() methods of ipaddress.IPv4Interface and
     ipaddress.IPv6Interface incorrectly generated constant hash values
     of 32 and 128 respectively.  This resulted in always causing hash
     collisions.  The fix uses hash() to generate hash values for the
     tuple of (address, mask length, network address).

   - bpo-39603(8): Prevent http header injection by rejecting control
     characters in http.client.putrequest(…).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41304

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29778

   (3) https://www.cve.org/CVERecord?id=CVE-2020-15801

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41162

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29778

   (6) https://www.cve.org/CVERecord?id=CVE-2020-15523

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41004

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39603


File: python.info,  Node: Core and Builtins<110>,  Next: Library<112>,  Prev: Security<33>,  Up: Python 3 10 0 alpha 1

1.23.51.2 Core and Builtins
...........................

   - bpo-41909(1): Fixed stack overflow in *note issubclass(): 7c5. and
     *note isinstance(): 445. when getting the ‘__bases__’ attribute
     leads to infinite recursion.

   - bpo-41922(2): Speed up calls to ‘reversed()’ by using the PEP
     590(3) ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-41873(4): Calls to ‘float()’ are now faster due to the
     ‘vectorcall’ calling convention.  Patch by Dennis Sweeney.

   - bpo-41870(5): Speed up calls to ‘bool()’ by using the PEP 590(6)
     ‘vectorcall’ calling convention.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41909

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41922

   (3) https://peps.python.org/pep-0590/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41873

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41870

   (6) https://peps.python.org/pep-0590/


File: python.info,  Node: Library<112>,  Next: Core and Builtins<111>,  Prev: Core and Builtins<110>,  Up: Python 3 10 0 alpha 1

1.23.51.3 Library
.................

   - bpo-1635741(1): Port the ‘_bisect’ module to the multi-phase
     initialization API ( PEP 489(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<111>,  Next: Library<113>,  Prev: Library<112>,  Up: Python 3 10 0 alpha 1

1.23.51.4 Core and Builtins
...........................

   - bpo-39934(1): Correctly count control blocks in ‘except’ in
     compiler.  Ensures that a syntax error, rather a fatal error,
     occurs for deeply nested, named exception handlers.

   - bpo-41780(2): Fix ‘__dir__()’ of *note types.GenericAlias: 7f0.
     Patch by Batuhan Taskaya.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39934

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41780


File: python.info,  Node: Library<113>,  Next: Core and Builtins<112>,  Prev: Core and Builtins<111>,  Up: Python 3 10 0 alpha 1

1.23.51.5 Library
.................

   - bpo-1635741(1): Port the ‘_lsprof’ extension module to multi-phase
     initialization ( PEP 489(2)).

   - bpo-1635741(3): Port the *note cmath: 18. extension module to
     multi-phase initialization ( PEP 489(4)).

   - bpo-1635741(5): Port the ‘_scproxy’ extension module to multi-phase
     initialization ( PEP 489(6)).

   - bpo-1635741(7): Port the *note termios: e1. extension module to
     multi-phase initialization ( PEP 489(8)).

   - bpo-1635741(9): Convert the ‘_sha256’ extension module types to
     heap types.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (4) https://peps.python.org/pep-0489/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (6) https://peps.python.org/pep-0489/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (8) https://peps.python.org/pep-0489/

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1635741


File: python.info,  Node: Core and Builtins<112>,  Next: Library<114>,  Prev: Library<113>,  Up: Python 3 10 0 alpha 1

1.23.51.6 Core and Builtins
...........................

   - bpo-41690(1): Fix a possible stack overflow in the parser when
     parsing functions and classes with a huge amount of arguments.
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41690


File: python.info,  Node: Library<114>,  Next: Core and Builtins<113>,  Prev: Core and Builtins<112>,  Up: Python 3 10 0 alpha 1

1.23.51.7 Library
.................

   - bpo-1635741(1): Port the ‘_overlapped’ extension module to
     multi-phase initialization ( PEP 489(2)).

   - bpo-1635741(3): Port the ‘_curses_panel’ extension module to
     multi-phase initialization ( PEP 489(4)).

   - bpo-1635741(5): Port the ‘_opcode’ extension module to multi-phase
     initialization ( PEP 489(6)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (4) https://peps.python.org/pep-0489/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (6) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<113>,  Next: Library<115>,  Prev: Library<114>,  Up: Python 3 10 0 alpha 1

1.23.51.8 Core and Builtins
...........................

   - bpo-41681(1): Fixes the wrong error description in the error raised
     by using 2 ‘,’ in format string in f-string and *note str.format():
     624.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41681


File: python.info,  Node: Library<115>,  Next: Core and Builtins<114>,  Prev: Core and Builtins<113>,  Up: Python 3 10 0 alpha 1

1.23.51.9 Library
.................

   - bpo-41675(1): The implementation of *note signal.siginterrupt():
     1179. now uses ‘sigaction()’ (if it is available in the system)
     instead of the deprecated ‘siginterrupt()’.  Patch by Pablo
     Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41675


File: python.info,  Node: Core and Builtins<114>,  Next: Library<116>,  Prev: Library<115>,  Up: Python 3 10 0 alpha 1

1.23.51.10 Core and Builtins
............................

   - bpo-41670(1): Prevent line trace being skipped on platforms not
     compiled with ‘USE_COMPUTED_GOTOS’.  Fixes issue where some lines
     nested within a try-except block were not being traced on Windows.

   - bpo-41654(2): Fix a crash that occurred when destroying subclasses
     of *note MemoryError: 15ab.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41670

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41654


File: python.info,  Node: Library<116>,  Next: Core and Builtins<115>,  Prev: Core and Builtins<114>,  Up: Python 3 10 0 alpha 1

1.23.51.11 Library
..................

   - bpo-1635741(1): Port the *note zlib: 133. extension module to
     multi-phase initialization ( PEP 489(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<115>,  Next: Library<117>,  Prev: Library<116>,  Up: Python 3 10 0 alpha 1

1.23.51.12 Core and Builtins
............................

   - bpo-41631(1): The ‘_ast’ module uses again a global state.  Using a
     module state per module instance is causing subtle practical
     problems.  For example, the Mercurial project replaces the
     ‘__import__()’ function to implement lazy import, whereas Python
     expected that ‘import _ast’ always return a fully initialized
     ‘_ast’ module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41631


File: python.info,  Node: Library<117>,  Next: Core and Builtins<116>,  Prev: Core and Builtins<115>,  Up: Python 3 10 0 alpha 1

1.23.51.13 Library
..................

   - bpo-40077(1): Convert ‘_operator’ to use *note PyType_FromSpec():
     580.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40077


File: python.info,  Node: Core and Builtins<116>,  Next: Library<118>,  Prev: Library<117>,  Up: Python 3 10 0 alpha 1

1.23.51.14 Core and Builtins
............................

   - bpo-1653741(1): Port ‘_sha3’ to multi-phase init.  Convert static
     types to heap types.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1653741


File: python.info,  Node: Library<118>,  Next: Core and Builtins<117>,  Prev: Core and Builtins<116>,  Up: Python 3 10 0 alpha 1

1.23.51.15 Library
..................

   - bpo-1635741(1): Port the ‘_blake2’ extension module to the
     multi-phase initialization API ( PEP 489(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<117>,  Next: Library<119>,  Prev: Library<118>,  Up: Python 3 10 0 alpha 1

1.23.51.16 Core and Builtins
............................

   - bpo-41533(1): Free the stack allocated in ‘va_build_stack’ if
     ‘do_mkstack’ fails and the stack is not a ‘small_stack’.

   - bpo-41531(2): Fix a bug that was dropping keys when compiling dict
     literals with more than 0xFFFF elements.  Patch by Pablo Galindo.

   - bpo-41525(3): The output of ‘python --help’ contains now only ASCII
     characters.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41533

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41531

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41525


File: python.info,  Node: Library<119>,  Next: Core and Builtins<118>,  Prev: Core and Builtins<117>,  Up: Python 3 10 0 alpha 1

1.23.51.17 Library
..................

   - bpo-1635741(1): Port the ‘_sha1’, ‘_sha512’, and ‘_md5’ extension
     modules to multi-phase initialization API ( PEP 489(2)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Core and Builtins<118>,  Next: Library<120>,  Prev: Library<119>,  Up: Python 3 10 0 alpha 1

1.23.51.18 Core and Builtins
............................

   - bpo-41431(1): Optimize ‘dict_merge()’ for copying dict (e.g.
     ‘dict(d)’ and ‘{}.update(d)’).

   - bpo-41428(2): Implement PEP 604.  This supports (int | str) etc.
     in place of Union[str, int].

   - bpo-41340(3): Removed fallback implementation for ‘strdup’.

   - bpo-38156(4): Handle interrupts that come after EOF correctly in
     ‘PyOS_StdioReadline’.

   - bpo-41342(5): *note round(): 1322. with integer argument is now
     faster (9–60%).

   - bpo-41334(6): Constructors *note str(): 44f, *note bytes(): 1c2.
     and *note bytearray(): 2ea. are now faster (around 30–40% for small
     objects).

   - bpo-41295(7): Resolve a regression in CPython 3.8.4 where defining
     “__setattr__” in a multi-inheritance setup and calling up the
     hierarchy chain could fail if builtins/extension types were
     involved in the base types.

   - bpo-41323(8): Bytecode optimizations are performed directly on the
     control flow graph.  This will result in slightly more compact code
     objects in some circumstances.

   - bpo-41247(9): Always cache the running loop holder when running
     ‘asyncio.set_running_loop’.

   - bpo-41252(10): Fix incorrect refcounting in _ssl.c’s
     ‘_servername_callback()’.

   - bpo-1635741(11): Port *note multiprocessing: 94. to multi-phase
     initialization

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41431

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41428

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41340

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38156

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41342

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41334

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41295

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41323

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41247

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41252

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1635741


File: python.info,  Node: Library<120>,  Next: Core and Builtins<119>,  Prev: Core and Builtins<118>,  Up: Python 3 10 0 alpha 1

1.23.51.19 Library
..................

   - bpo-1635741(1): Port ‘winapi’ to multiphase initialization

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741


File: python.info,  Node: Core and Builtins<119>,  Next: Library<121>,  Prev: Library<120>,  Up: Python 3 10 0 alpha 1

1.23.51.20 Core and Builtins
............................

   - bpo-41215(1): Use non-NULL default values in the PEG parser keyword
     list to overcome a bug that was preventing Python from being
     properly compiled when using the XLC compiler.  Patch by Pablo
     Galindo.

   - bpo-41218(2): Python 3.8.3 had a regression where compiling with
     ast.PyCF_ALLOW_TOP_LEVEL_AWAIT would aggressively mark list
     comprehension with CO_COROUTINE. Now only list comprehension making
     use of async/await will tagged as so.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41215

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41218


File: python.info,  Node: Library<121>,  Next: Core and Builtins<120>,  Prev: Core and Builtins<119>,  Up: Python 3 10 0 alpha 1

1.23.51.21 Library
..................

   - bpo-1635741(1): Port *note faulthandler: 58. to multiphase
     initialization.

   - bpo-1635741(2): Port ‘sha256’ to multiphase initialization

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1635741


File: python.info,  Node: Core and Builtins<120>,  Next: Library<122>,  Prev: Library<121>,  Up: Python 3 10 0 alpha 1

1.23.51.22 Core and Builtins
............................

   - bpo-41175(1): Guard against a NULL pointer dereference within
     bytearrayobject triggered by the ‘bytearray() + bytearray()’
     operation.

   - bpo-41100(2): add arm64 to the allowable Mac OS arches in
     mpdecimal.h

   - bpo-41094(3): Fix decoding errors with audit when open files with
     non-ASCII names on non-UTF-8 locale.

   - bpo-39960(4): The “hackcheck” that prevents sneaking around a
     type’s __setattr__() by calling the superclass method was rewritten
     to allow C implemented heap types.

   - bpo-41084(5): Prefix the error message with ‘f-string: ‘, when
     parsing an f-string expression which throws a *note SyntaxError:
     18d.

   - bpo-40521(6): Empty frozensets are no longer singletons.

   - bpo-41076(7): Pre-feed the parser with the location of the f-string
     expression, not the f-string itself, which allows us to skip the
     shifting of the AST node locations after the parsing is completed.

   - bpo-41056(8): Fixes a reference to deallocated stack space during
     startup when constructing sys.path involving a relative symlink
     when code was supplied via -c.  (discovered via Coverity)

   - bpo-41061(9): Fix incorrect expressions and asserts in hashtable
     code and tests.

   - bpo-41052(10): Opt out serialization/deserialization for
     _random.Random

   - bpo-40939(11): Rename ‘PyPegen*’ functions to ‘PyParser*’, so that
     we can remove the old set of ‘PyParser*’ functions that were using
     the old parser, but keep everything backwards-compatible.

   - bpo-35975(12): Stefan Behnel reported that cf_feature_version is
     used even when PyCF_ONLY_AST is not set.  This is against the
     intention and against the documented behavior, so it’s been fixed.

   - bpo-40939(13): Remove the remaining files from the old parser and
     the ‘symbol’ module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41175

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41100

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41094

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39960

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41084

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40521

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41076

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41056

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41061

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41052

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40939

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35975

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40939


File: python.info,  Node: Library<122>,  Next: Core and Builtins<121>,  Prev: Core and Builtins<120>,  Up: Python 3 10 0 alpha 1

1.23.51.23 Library
..................

   - bpo-40077(1): Convert ‘_bz2’ to use *note PyType_FromSpec(): 580.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40077


File: python.info,  Node: Core and Builtins<121>,  Next: Library<123>,  Prev: Library<122>,  Up: Python 3 10 0 alpha 1

1.23.51.24 Core and Builtins
............................

   - bpo-41006(1): The ‘encodings.latin_1’ module is no longer imported
     at startup.  Now it is only imported when it is the filesystem
     encoding or the stdio encoding.

   - bpo-40636(2): *note zip(): 7d4. now supports PEP 618(3)’s ‘strict’
     parameter, which raises a *note ValueError: 202. if the arguments
     are exhausted at different lengths.  Patch by Brandt Bucher.

   - bpo-1635741(4): Port ‘_gdbm’ to multiphase initialization.

   - bpo-40985(5): Fix a bug that caused the *note SyntaxError: 18d.
     text to be empty when a file ends with a line ending in a line
     continuation character (i.e.  backslash).  The error text should
     contain the text of the last line.

   - bpo-40958(6): Fix a possible buffer overflow in the PEG parser when
     gathering information for emitting syntax errors.  Patch by Pablo
     Galindo.

   - bpo-1635741(7): Port ‘_dbm’ to multiphase initialization.

   - bpo-40957(8): Fix refleak in _Py_fopen_obj() when PySys_Audit()
     fails

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41006

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40636

   (3) https://peps.python.org/pep-0618/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40985

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40958

   (7) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40957


File: python.info,  Node: Library<123>,  Next: Core and Builtins<122>,  Prev: Core and Builtins<121>,  Up: Python 3 10 0 alpha 1

1.23.51.25 Library
..................

   - bpo-40950(1): Add a state to the ‘nis’ module ( PEP 3121(2)) and
     apply the multiphase initialization.  Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40950

   (2) https://peps.python.org/pep-3121/


File: python.info,  Node: Core and Builtins<122>,  Next: Library<124>,  Prev: Library<123>,  Up: Python 3 10 0 alpha 1

1.23.51.26 Core and Builtins
............................

   - bpo-40947(1): The Python *note Path Configuration: 8b5. now takes
     *note PyConfig.platlibdir: 1ac8. in account.

   - bpo-40939(2): Remove the old parser, the ‘parser’ module and all
     associated support code, command-line options and environment
     variables.  Patch by Pablo Galindo.

   - bpo-40847(3): Fix a bug where a line with only a line continuation
     character is not considered a blank line at tokenizer level.  In
     such cases, more than a single ‘NEWLINE’ token was emitted.  The
     old parser was working around the issue, but the new parser threw a
     *note SyntaxError: 18d. for valid input due to this.  For example,
     an empty line following a line continuation character was
     interpreted as a ‘SyntaxError’.

   - bpo-40890(4): Each dictionary view now has a ‘mapping’ attribute
     that provides a *note types.MappingProxyType: 470. wrapping the
     original dictionary.  Patch contributed by Dennis Sweeney.

   - bpo-40889(5): Improved the performance of symmetric difference
     operations on dictionary item views.  Patch by Dennis Sweeney.

   - bpo-40904(6): Fix possible segfault in the new PEG parser when
     parsing f-string containing yield statements with no value
     (‘f"{yield}"’).  Patch by Pablo Galindo

   - bpo-40903(7): Fixed a possible segfault in the new PEG parser when
     producing error messages for invalid assignments of the form
     ‘p=p=’.  Patch by Pablo Galindo

   - bpo-40880(8): Fix invalid memory read in the new parser when
     checking newlines in string literals.  Patch by Pablo Galindo.

   - bpo-40883(9): Fix memory leak in when parsing f-strings in the new
     parser.  Patch by Pablo Galindo

   - bpo-40870(10): Raise *note ValueError: 202. when validating custom
     AST’s where the constants ‘True’, ‘False’ and ‘None’ are used
     within a *note ast.Name: 1ac9. node.

   - bpo-40854(11): Allow overriding *note sys.platlibdir: 942. via a
     new *note PYTHONPLATLIBDIR: 1aca. environment variable.

   - bpo-40826(12): Fix GIL usage in ‘PyOS_Readline()’: lock the GIL to
     set an exception and pass the Python thread state when checking if
     there is a pending signal.

   - bpo-1635741(13): Port *note fcntl: 59. to multiphase
     initialization.

   - bpo-19468(14): Delete unnecessary instance check in
     importlib.reload().  Patch by Furkan Önder.

   - bpo-40824(15): Unexpected errors in calling the ‘__iter__’ method
     are no longer masked by ‘TypeError’ in the *note in: 2f4. operator
     and functions *note contains(): 8e3, *note indexOf(): 8e4. and
     *note countOf(): 8e5. of the *note operator: 9f. module.

   - bpo-40792(16): Attributes ‘start’, ‘stop’ and ‘step’ of the *note
     range: 94d. object now always has exact type *note int: 257.
     Previously, they could have been an instance of a subclass of
     ‘int’.

   - bpo-40780(17): Fix a corner case where g-style string formatting of
     a float failed to remove trailing zeros.

   - bpo-38964(18): When there’s a *note SyntaxError: 18d. in the
     expression part of an fstring, the filename attribute of the
     ‘SyntaxError’ gets correctly set to the name of the file the
     fstring resides in.

   - bpo-40750(19): Support the “-d” debug flag in the new PEG parser.
     Patch by Pablo Galindo

   - bpo-40217(20): Instances of types created with *note
     PyType_FromSpecWithBases(): 581. will no longer automatically visit
     their class object when traversing references in the garbage
     collector.  The user is expected to manually visit the object’s
     class.  Patch by Pablo Galindo.

   - bpo-39573(21): *note Py_TYPE(): 783. is changed to the inline
     static function.  Patch by Donghee Na.

   - bpo-40696(22): Fix a hang that can arise after *note
     generator.throw(): 4fb. due to a cycle in the exception context
     chain.

   - bpo-40521(23): Each interpreter now its has own free lists,
     singletons and caches:

        * Free lists: float, tuple, list, dict, frame, context,
          asynchronous generator, MemoryError.

        * Singletons: empty tuple, empty bytes string, empty Unicode
          string, single byte character, single Unicode (latin1)
          character.

        * Slice cache.

     They are no longer shared by all interpreters.

   - bpo-40679(24): Certain *note TypeError: 2c3. messages about missing
     or extra arguments now include the function’s *note qualified name:
     1acb.  Patch by Dennis Sweeney.

   - bpo-29590(25): Make the stack trace correct after calling *note
     generator.throw(): 4fb. on a generator that has yielded from a
     ‘yield from’.

   - bpo-4022(26): Improve performance of generators by not raising
     internal StopIteration.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40947

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40939

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40847

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40890

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40889

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40904

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40903

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40880

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40883

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40870

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40854

   (12) https://bugs.python.org/issue?@action=redirect&bpo=40826

   (13) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (14) https://bugs.python.org/issue?@action=redirect&bpo=19468

   (15) https://bugs.python.org/issue?@action=redirect&bpo=40824

   (16) https://bugs.python.org/issue?@action=redirect&bpo=40792

   (17) https://bugs.python.org/issue?@action=redirect&bpo=40780

   (18) https://bugs.python.org/issue?@action=redirect&bpo=38964

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40750

   (20) https://bugs.python.org/issue?@action=redirect&bpo=40217

   (21) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40696

   (23) https://bugs.python.org/issue?@action=redirect&bpo=40521

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40679

   (25) https://bugs.python.org/issue?@action=redirect&bpo=29590

   (26) https://bugs.python.org/issue?@action=redirect&bpo=4022


File: python.info,  Node: Library<124>,  Next: Core and Builtins<123>,  Prev: Core and Builtins<122>,  Up: Python 3 10 0 alpha 1

1.23.51.27 Library
..................

   - bpo-1635741(1): Port *note mmap: 90. to multiphase initialization.

   - bpo-1635741(2): Port ‘_lzma’ to multiphase initialization.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1635741


File: python.info,  Node: Core and Builtins<123>,  Next: Library<125>,  Prev: Library<124>,  Up: Python 3 10 0 alpha 1

1.23.51.28 Core and Builtins
............................

   - bpo-37999(1): Builtin and extension functions that take integer
     arguments no longer accept *note Decimal: 29d.s, *note Fraction:
     1e7.s and other objects that can be converted to integers only with
     a loss (e.g.  that have the *note __int__(): 71f. method but do not
     have the *note __index__(): 720. method).

   - bpo-29882(2): Add *note int.bit_count(): 7d0, counting the number
     of ones in the binary representation of an integer.  Patch by
     Niklas Fiekas.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37999

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29882


File: python.info,  Node: Library<125>,  Next: Core and Builtins<124>,  Prev: Core and Builtins<123>,  Up: Python 3 10 0 alpha 1

1.23.51.29 Library
..................

   - bpo-36982(1): Use ncurses extended color functions when available
     to support terminals with 256 colors, and add the new function
     *note curses.has_extended_color_support(): 7fa. to indicate whether
     extended color support is provided by the underlying ncurses
     library.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36982


File: python.info,  Node: Core and Builtins<124>,  Next: Library<126>,  Prev: Library<125>,  Up: Python 3 10 0 alpha 1

1.23.51.30 Core and Builtins
............................

   - bpo-19569(1): Add the private macros ‘_Py_COMP_DIAG_PUSH’,
     ‘_Py_COMP_DIAG_IGNORE_DEPR_DECLS’, and ‘_Py_COMP_DIAG_POP’.

   - bpo-26680(2): The int type now supports the x.is_integer() method
     for compatibility with float.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19569

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26680


File: python.info,  Node: Library<126>,  Next: Documentation<42>,  Prev: Core and Builtins<124>,  Up: Python 3 10 0 alpha 1

1.23.51.31 Library
..................

   - bpo-41900(1): C14N 2.0 serialisation in xml.etree.ElementTree
     failed for unprefixed attributes when a default namespace was
     defined.

   - bpo-41887(2): Strip leading spaces and tabs on *note
     ast.literal_eval(): c38.  Also document stripping of spaces and
     tabs for *note eval(): 180.

   - bpo-41773(3): Note in documentation that *note random.choices():
     cec. doesn’t support non-finite weights, raise *note ValueError:
     202. when given non-finite weights.

   - bpo-41840(4): Fix a bug in the *note symtable: d8. module that was
     causing module-scope global variables to not be reported as both
     local and global.  Patch by Pablo Galindo.

   - bpo-41842(5): Add *note codecs.unregister(): 7ed. function to
     unregister a codec search function.

   - bpo-40564(6): In ‘zipfile.Path’, mutate the passed ZipFile object
     type instead of making a copy.  Prevents issues when both the local
     copy and the caller’s copy attempt to close the same file handle.

   - bpo-40670(7): More reliable validation of statements in *note
     timeit.Timer: 1517.  It now accepts “empty” statements (only
     whitespaces and comments) and rejects misindentent statements.

   - bpo-41833(8): The *note threading.Thread: 956. constructor now uses
     the target name if the 'target' argument is specified but the
     'name' argument is omitted.

   - bpo-41817(9): fix ‘tkinter.EventType’ Enum so all members are
     strings, and none are tuples

   - bpo-41810(10): *note types.EllipsisType: 857, *note
     types.NotImplementedType: 859. and *note types.NoneType: 858. have
     been reintroduced, providing a new set of types readily
     interpretable by static type checkers.

   - bpo-41815(11): Fix SQLite3 segfault when backing up closed
     database.  Patch contributed by Peter David McCormick.

   - bpo-41816(12): StrEnum added: it ensures that all members are
     already strings or string candidates

   - bpo-41517(13): fix bug allowing Enums to be extended via multiple
     inheritance

   - bpo-39587(14): use the correct mix-in data type when constructing
     Enums

   - bpo-41792(15): Add is_typeddict function to typing.py to check if a
     type is a TypedDict class

     Previously there was no way to check that without using private
     API.  See the relevant issue in python/typing(16).

   - bpo-41789(17): Honor ‘object’ overrides in ‘Enum’ class creation
     (specifically, ‘__str__’, ‘__repr__’, ‘__format__’, and
     ‘__reduce_ex__’).

   - bpo-32218(18): ‘enum.Flag’ and ‘enum.IntFlag’ members are now
     iterable.

   - bpo-39651(19): Fix a race condition in the ‘call_soon_threadsafe()’
     method of ‘asyncio.ProactorEventLoop’: do nothing if the self-pipe
     socket has been closed.

   - bpo-1635741(20): Port the ‘mashal’ extension module to the
     multi-phase initialization API ( PEP 489(21)).

   - bpo-1635741(22): Port the ‘_string’ extension module to the
     multi-phase initialization API ( PEP 489(23)).

   - bpo-41732(24): Added an *note iterator: 1ac. to *note memoryview:
     2eb.

   - bpo-41720(25): Fixed ‘turtle.Vec2D.__rmul__()’ for arguments which
     are not int or float.

   - bpo-41696(26): Fix handling of debug mode in *note asyncio.run():
     47f.  This allows setting ‘PYTHONASYNCIODEBUG’ or ‘-X dev’ to
     enable asyncio debug mode when using ‘asyncio.run()’.

   - bpo-41687(27): Fix implementation of sendfile to be compatible with
     Solaris.

   - bpo-41662(28): No longer override exceptions raised in ‘__len__()’
     of a sequence of parameters in *note sqlite3: cf. with *note
     ProgrammingError: 4f5.

   - bpo-39010(29): Restarting a ‘ProactorEventLoop’ on Windows no
     longer logs spurious ‘ConnectionResetErrors’.

   - bpo-41638(30): *note ProgrammingError: 4f5. message for absent
     parameter in *note sqlite3: cf. contains now the name of the
     parameter instead of its index when parameters are supplied as a
     dict.

   - bpo-41662(31): Fixed crash when mutate list of parameters during
     iteration in *note sqlite3: cf.

   - bpo-41513(32): Improved the accuracy of math.hypot().  Internally,
     each step is computed with extra precision so that the result is
     now almost always correctly rounded.

   - bpo-41609(33): The pdb whatis command correctly reports instance
     methods as ‘Method’ rather than ‘Function’.

   - bpo-39994(34): Fixed pprint’s handling of dict subclasses that
     override __repr__.

   - bpo-32751(35): When cancelling the task due to a timeout, *note
     asyncio.wait_for(): 602. will now wait until the cancellation is
     complete also in the case when 'timeout' is <= 0, like it does with
     positive timeouts.

   - bpo-37658(36): *note asyncio.wait_for(): 602. now properly handles
     races between cancellation of itself and the completion of the
     wrapped awaitable.

   - bpo-40782(37): Change the method
     asyncio.AbstractEventLoop.run_in_executor to not be a coroutine.

   - bpo-41520(38): Fix *note codeop: 1c. regression that prevented
     turning compile warnings into errors.

   - bpo-41528(39): turtle uses math module functions to convert degrees
     to radians and vice versa and to calculate vector norm

   - bpo-41513(40): Minor algorithmic improvement to math.hypot() and
     math.dist() giving small gains in speed and accuracy.

   - bpo-41503(41): Fixed a race between setTarget and flush in
     logging.handlers.MemoryHandler.

   - bpo-41497(42): Fix potential UnicodeDecodeError in dis module.

   - bpo-41467(43): On Windows, fix asyncio ‘recv_into()’ return value
     when the socket/pipe is closed (*note BrokenPipeError: 109a.):
     return ‘0’ rather than an empty byte string (‘b''’).

   - bpo-41425(44): Make tkinter doc example runnable.

   - bpo-41421(45): Make an algebraic simplification to
     random.paretovariate().  It now is slightly less subject to
     round-off error and is slightly faster.  Inputs that used to cause
     ZeroDivisionError now cause an OverflowError instead.

   - bpo-41440(46): Add *note os.cpu_count(): 1c5. support for VxWorks
     RTOS.

   - bpo-41316(47): Fix the *note tarfile: de. module to write only
     basename of TAR file to GZIP compression header.

   - bpo-41384(48): Raise TclError instead of TypeError when an unknown
     option is passed to tkinter.OptionMenu.

   - bpo-41317(49): Use add_done_callback() in
     asyncio.loop.sock_accept() to unsubscribe reader early on
     cancellation.

   - bpo-41364(50): Reduce import overhead of *note uuid: 110.

   - bpo-35328(51): Set the environment variable ‘VIRTUAL_ENV_PROMPT’ at
     *note venv: 111. activation.

   - bpo-41341(52): Recursive evaluation of ‘typing.ForwardRef’ in
     ‘get_type_hints’.

   - bpo-41344(53): Prevent creating ‘shared_memory.SharedMemory’
     objects with ‘size=0’.

   - bpo-41333(54): ‘collections.OrderedDict.pop()’ is now 2 times
     faster.

   - bpo-41288(55): Unpickling invalid NEWOBJ_EX opcode with the C
     implementation raises now UnpicklingError instead of crashing.

   - bpo-39017(56): Avoid infinite loop when reading specially crafted
     TAR files using the tarfile module ( CVE 2019-20907(57)).

   - bpo-41273(58): Speed up any transport using
     ‘_ProactorReadPipeTransport’ by calling ‘recv_into’ instead of
     ‘recv’, thus not creating a new buffer for each ‘recv’ call in the
     transport’s read loop.

   - bpo-41235(59): Fix the error handling in *note
     ssl.SSLContext.load_dh_params(): 1186.

   - bpo-41207(60): In distutils.spawn, restore expectation that
     DistutilsExecError is raised when the command is not found.

   - bpo-29727(61): Register *note array.array: 1a0. as a *note
     MutableSequence: 1a1.  Patch by Pablo Galindo.

   - bpo-39168(62): Remove the ‘__new__’ method of *note typing.Generic:
     15fb.

   - bpo-41194(63): Fix a crash in the ‘_ast’ module: it can no longer
     be loaded more than once.  It now uses a global state rather than a
     module state.

   - bpo-41195(64): Add read-only ssl.SSLContext.security_level
     attribute to retrieve the context’s security level.

   - bpo-41193(65): The ‘write_history()’ atexit function of the
     readline completer now ignores any *note OSError: 41a. to ignore
     error if the filesystem is read-only, instead of only ignoring
     *note FileNotFoundError: 42e. and *note PermissionError: d6b.

   - bpo-41182(66): selector: use DefaultSelector based upon
     implementation

   - bpo-41161(67): The decimal module now requires libmpdec-2.5.0.
     Users of –with-system-libmpdec should update their system library.

   - bpo-40874(68): The decimal module now requires libmpdec-2.5.0.

   - bpo-41138(69): Fixed the *note trace: fd. module CLI for Python
     source files with non-UTF-8 encoding.

   - bpo-31082(70): Use the term “iterable” in the docstring for *note
     functools.reduce(): 1324.

   - bpo-40521(71): Remove freelist from collections.deque().

   - bpo-31938(72): Fix default-value signatures of several functions in
     the *note select: c1. module - by Anthony Sottile.

   - bpo-41068(73): Fixed reading files with non-ASCII names from ZIP
     archive directly after writing them.

   - bpo-41058(74): ‘pdb.find_function()’ now correctly determines the
     source file encoding.

   - bpo-41056(75): Invalid file descriptor values are now prevented
     from being passed to os.fpathconf.  (discovered by Coverity)

   - bpo-41056(76): Fix a NULL pointer dereference within the ssl module
     during a MemoryError in the keylog callback.  (discovered by
     Coverity)

   - bpo-41056(77): Fixed an instance where a MemoryError within the
     zoneinfo module might not be reported or not reported at its
     source.  (found by Coverity)

   - bpo-41048(78): *note mimetypes.read_mime_types(): 1ad1. function
     reads the rule file using UTF-8 encoding, not the locale encoding.
     Patch by Srinivas Reddy Thatiparthy.

   - bpo-41043(79): Fixed the use of *note glob(): 29f. in the stdlib:
     literal part of the path is now always correctly escaped.

   - bpo-41025(80): Fixed an issue preventing the C implementation of
     *note zoneinfo.ZoneInfo: 8e8. from being subclassed.

   - bpo-35018(81): Add the *note xml.sax.handler.LexicalHandler: 862.
     class that is present in other SAX XML implementations.

   - bpo-41002(82): Improve performance of HTTPResponse.read with a
     given amount.  Patch by Bruce Merry.

   - bpo-40448(83): *note ensurepip: 55. now disables the use of ‘pip’
     cache when installing the bundled versions of ‘pip’ and
     ‘setuptools’.  Patch by Krzysztof Konopko.

   - bpo-40967(84): Removed ‘asyncio.Task.current_task()’ and
     ‘asyncio.Task.all_tasks()’.  Patch contributed by Rémi Lapeyre.

   - bpo-40924(85): Ensure ‘importlib.resources.path’ returns an extant
     path for the SourceFileLoader’s resource reader.  Avoids the
     regression identified in master while a long-term solution is
     devised.

   - bpo-40955(86): Fix a minor memory leak in *note subprocess: d6.
     module when extra_groups was specified.

   - bpo-40855(87): The standard deviation and variance functions in the
     statistics module were ignoring their mu and xbar arguments.

   - bpo-40939(88): Use the new PEG parser when generating the stdlib
     *note keyword: 84. module.

   - bpo-23427(89): Add *note sys.orig_argv: 846. attribute: the list of
     the original command line arguments passed to the Python
     executable.

   - bpo-33689(90): Ignore empty or whitespace-only lines in .pth files.
     This matches the documentated behavior.  Before, empty lines caused
     the site-packages dir to appear multiple times in sys.path.  By Ido
     Michael, contributors Malcolm Smith and Tal Einat.

   - bpo-40884(91): Added a ‘defaults’ parameter to *note
     logging.Formatter: 14e6, to allow specifying default values for
     custom fields.  Patch by Asaf Alon and Bar Harel.

   - bpo-40876(92): Clarify error message in the *note csv: 29. module.

   - bpo-39791(93): Refresh importlib.metadata from importlib_metadata
     1.6.1.

   - bpo-40807(94): Stop codeop._maybe_compile, used by
     code.InteractiveInterpreter (and IDLE). from emitting each warning
     three times.

   - bpo-32604(95): Fix reference leak in the *note select: c1. module
     when the module is imported in a subinterpreter.

   - bpo-39791(96): Built-in loaders (SourceFileLoader and ZipImporter)
     now supply ‘TraversableResources’ implementations for
     ‘ResourceReader’, and the fallback function has been removed.

   - bpo-39314(97): *note rlcompleter.Completer: 1ad2. and the standard
     Python shell now close the parenthesis for functions that take no
     arguments.  Patch contributed by Rémi Lapeyre.

   - bpo-17005(98): The topological sort functionality that was
     introduced initially in the *note functools: 5f. module has been
     moved to a new *note graphlib: 65. module to better accommodate the
     new tools and keep the original scope of the ‘functools’ module.
     Patch by Pablo Galindo

   - bpo-40834(99): Fix truncate when sending str object
     with_xxsubinterpreters.channel_send.

   - bpo-40755(100): Add rich comparisons to collections.Counter().

   - bpo-26407(101): Unexpected errors in calling the ‘__iter__’ method
     are no longer masked by ‘TypeError’ in *note csv.reader(): 489,
     ‘csv.writer.writerow()’ and ‘csv.writer.writerows()’.

   - bpo-39384(102): Fixed email.contentmanager to allow set_content()
     to set a null string.

   - bpo-40744(103): The *note sqlite3: cf. module uses SQLite API
     functions that require SQLite v3.7.3 or higher.  This patch removes
     support for older SQLite versions, and explicitly requires SQLite
     3.7.3 both at build, compile and runtime.  Patch by Sergey Fedoseev
     and Erlend E. Aasland.

   - bpo-40777(104): Initialize PyDateTime_IsoCalendarDateType.tp_base
     at run-time to avoid errors on some compilers.

   - bpo-38488(105): Update ensurepip to install pip 20.1.1 and
     setuptools 47.1.0.

   - bpo-40792(106): The result of *note operator.index(): 1a78. now
     always has exact type *note int: 257.  Previously, the result could
     have been an instance of a subclass of ‘int’.

   - bpo-40767(107): *note webbrowser: 115. now properly finds the
     default browser in pure Wayland systems by checking the
     WAYLAND_DISPLAY environment variable.  Patch contributed by Jérémy
     Attali.

   - bpo-40791(108): ‘hashlib.compare_digest()’ uses OpenSSL’s
     ‘CRYPTO_memcmp()’ function when OpenSSL is available.

   - bpo-40795(109): *note ctypes: 2a. module: If ctypes fails to
     convert the result of a callback or if a ctypes callback function
     raises an exception, sys.unraisablehook is now called with an
     exception set.  Previously, the error was logged into stderr by
     *note PyErr_Print(): 1ad3.

   - bpo-16995(110): Add *note base64.b32hexencode(): 7e8. and *note
     base64.b32hexdecode(): 7e9. to support the Base32 Encoding with
     Extended Hex Alphabet.

   - bpo-30008(111): Fix *note ssl: d0. code to be compatible with
     OpenSSL 1.1.x builds that use ‘no-deprecated’ and ‘--api=1.1.0’.

   - bpo-30064(112): Fix asyncio ‘loop.sock_*’ race condition issue

   - bpo-40759(113): Deprecate the ‘symbol’ module.

   - bpo-40756(114): The second argument (extra) of
     ‘LoggerAdapter.__init__’ now defaults to None.

   - bpo-37129(115): Add a new *note os.RWF_APPEND: 1ad4. flag for *note
     os.pwritev(): b7c.

   - bpo-40737(116): Fix possible reference leak for *note sqlite3: cf.
     initialization.

   - bpo-40726(117): Handle cases where the ‘end_lineno’ is ‘None’ on
     *note ast.increment_lineno(): 18b0.

   - bpo-40698(118): ‘distutils’ upload creates SHA2-256 and Blake2b-256
     digests.  MD5 digests is skipped if platform blocks MD5.

   - bpo-40695(119): *note hashlib: 68. no longer falls back to builtin
     hash implementations when OpenSSL provides a hash digest and the
     algorithm is blocked by security policy.

   - bpo-9216(120): *note hashlib.new(): 1ad5. passed ‘usedforsecurity’
     to OpenSSL EVP constructor ‘_hashlib.new()’.  test_hashlib and
     test_smtplib handle strict security policy better.

   - bpo-40614(121): *note ast.parse(): 1a8. will not parse self
     documenting expressions in f-strings when passed ‘feature_version’
     is less than ‘(3, 8)’.

   - bpo-40626(122): Add h5 file extension as MIME Type
     application/x-hdf5, as per HDF Group recommendation for HDF5
     formatted data files.  Patch contributed by Mark Schwab.

   - bpo-25920(123): On macOS, when building Python for macOS 10.4 and
     older, which wasn’t the case for python.org macOS installer, *note
     socket.getaddrinfo(): 15ba. no longer uses an internal lock to
     prevent race conditions when calling ‘getaddrinfo()’ which is
     thread-safe since macOS 10.5.  Python 3.9 requires macOS 10.6 or
     newer.  The internal lock caused random hang on fork when another
     thread was calling ‘socket.getaddrinfo()’.  The lock was also used
     on FreeBSD older than 5.3, OpenBSD older than 201311 and NetBSD
     older than 4.

   - bpo-40671(124): Prepare ‘_hashlib’ for PEP 489(125) and use *note
     PyModule_AddType(): 97f.

   - bpo-32309(126): Added a new *note coroutine: 494. *note
     asyncio.to_thread(): 8f1.  It is mainly used for running IO-bound
     functions in a separate thread to avoid blocking the event loop,
     and essentially works as a high-level version of *note
     run_in_executor(): 8f2. that can directly take keyword arguments.

   - bpo-36543(127): Restored the deprecated ‘xml.etree.cElementTree’
     module.

   - bpo-40611(128): *note MAP_POPULATE: 1ad6. constant has now been
     added to the list of exported *note mmap: 90. module flags.

   - bpo-39881(129): PEP 554 for use in the test suite.  (Patch By
     Joannah Nanjekye)

   - bpo-13097(130): ‘ctypes’ now raises an ‘ArgumentError’ when a
     callback is invoked with more than 1024 arguments.

   - bpo-39385(131): A new test assertion context-manager,
     ‘unittest.assertNoLogs()’ will ensure a given block of code emits
     no log messages using the logging module.  Contributed by Kit Yan
     Choi.

   - bpo-23082(132): Updated the error message and docs of
     PurePath.relative_to() to better reflect the function behaviour.

   - bpo-40318(133): Use SQLite3 trace v2 API, if it is available.

   - bpo-40105(134): ZipFile truncates files to avoid corruption when a
     shorter comment is provided in append (“a”) mode.  Patch by Jan
     Mazur.

   - bpo-40084(135): Fix ‘Enum.__dir__’: dir(Enum.member) now includes
     attributes as well as methods.

   - bpo-31122(136): ssl.wrap_socket() now raises ssl.SSLEOFError rather
     than OSError when peer closes connection during TLS negotiation

   - bpo-39728(137): fix default ‘_missing_’ so a duplicate ‘ValueError’
     is not set as the ‘__context__’ of the original ‘ValueError’.

   - bpo-39244(138): Fixed
     ‘multiprocessing.context.get_all_start_methods’ to properly return
     the default method first on macOS.

   - bpo-39040(139): Fix parsing of invalid mime headers parameters by
     collapsing whitespace between encoded words in a bare-quote-string.

   - bpo-38731(140): Add ‘--quiet’ option to command-line interface of
     *note py_compile: b3.  Patch by Gregory Schevchenko.

   - bpo-35714(141): *note struct.error: 136d. is now raised if there is
     a null character in a *note struct: d5. format string.

   - bpo-38144(142): Added the 'root_dir' and 'dir_fd' parameters in
     *note glob.glob(): 29f.

   - bpo-26543(143): Fix ‘IMAP4.noop()’ when debug mode is enabled (ex:
     ‘imaplib.Debug = 3’).

   - bpo-12178(144): *note csv.writer(): 48a. now correctly escapes
     'escapechar' when input contains 'escapechar'.  Patch by Catalin
     Iacob, Berker Peksag, and Itay Elbirt.

   - bpo-36290(145): AST nodes are now raising *note TypeError: 2c3. on
     conflicting keyword arguments.  Patch contributed by Rémi Lapeyre.

   - bpo-33944(146): Added site.py site-packages tracing in verbose
     mode.

   - bpo-35078(147): Refactor formatweekday, formatmonthname methods in
     LocaleHTMLCalendar and LocaleTextCalendar classes in calendar
     module to call the base class methods.This enables customizable CSS
     classes for LocaleHTMLCalendar.  Patch by Srinivas Reddy
     Thatiparthy

   - bpo-29620(148): *note assertWarns(): 11a8. no longer raises a
     ‘RuntimeException’ when accessing a module’s ‘__warningregistry__’
     causes importation of a new module, or when a new module is
     imported in another thread.  Patch by Kernc.

   - bpo-31844(149): Remove ‘ParserBase.error()’ method from the private
     and undocumented ‘_markupbase’ module.  *note
     html.parser.HTMLParser: 87e. is the only subclass of ‘ParserBase’
     and its ‘error()’ implementation was deprecated in Python 3.4 and
     removed in Python 3.5.

   - bpo-34226(150): Fix ‘cgi.parse_multipart’ without content_length.
     Patch by Roger Duran

   - bpo-33660(151): Fix pathlib.PosixPath to resolve a relative path
     located on the root directory properly.

   - bpo-28557(152): Improve the error message for a misbehaving
     ‘rawio.readinto’

   - bpo-26680(153): The d.is_integer() method is added to the Decimal
     type, for compatibility with other number types.

   - bpo-26680(154): The x.is_integer() method is incorporated into the
     abstract types of the numeric tower, Real, Rational and Integral,
     with appropriate default implementations.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41900

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41887

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41773

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41840

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41842

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40564

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40670

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41833

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41817

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41810

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41815

   (12) https://bugs.python.org/issue?@action=redirect&bpo=41816

   (13) https://bugs.python.org/issue?@action=redirect&bpo=41517

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39587

   (15) https://bugs.python.org/issue?@action=redirect&bpo=41792

   (16) https://github.com/python/typing/issues/751

   (17) https://bugs.python.org/issue?@action=redirect&bpo=41789

   (18) https://bugs.python.org/issue?@action=redirect&bpo=32218

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39651

   (20) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (21) https://peps.python.org/pep-0489/

   (22) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (23) https://peps.python.org/pep-0489/

   (24) https://bugs.python.org/issue?@action=redirect&bpo=41732

   (25) https://bugs.python.org/issue?@action=redirect&bpo=41720

   (26) https://bugs.python.org/issue?@action=redirect&bpo=41696

   (27) https://bugs.python.org/issue?@action=redirect&bpo=41687

   (28) https://bugs.python.org/issue?@action=redirect&bpo=41662

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39010

   (30) https://bugs.python.org/issue?@action=redirect&bpo=41638

   (31) https://bugs.python.org/issue?@action=redirect&bpo=41662

   (32) https://bugs.python.org/issue?@action=redirect&bpo=41513

   (33) https://bugs.python.org/issue?@action=redirect&bpo=41609

   (34) https://bugs.python.org/issue?@action=redirect&bpo=39994

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32751

   (36) https://bugs.python.org/issue?@action=redirect&bpo=37658

   (37) https://bugs.python.org/issue?@action=redirect&bpo=40782

   (38) https://bugs.python.org/issue?@action=redirect&bpo=41520

   (39) https://bugs.python.org/issue?@action=redirect&bpo=41528

   (40) https://bugs.python.org/issue?@action=redirect&bpo=41513

   (41) https://bugs.python.org/issue?@action=redirect&bpo=41503

   (42) https://bugs.python.org/issue?@action=redirect&bpo=41497

   (43) https://bugs.python.org/issue?@action=redirect&bpo=41467

   (44) https://bugs.python.org/issue?@action=redirect&bpo=41425

   (45) https://bugs.python.org/issue?@action=redirect&bpo=41421

   (46) https://bugs.python.org/issue?@action=redirect&bpo=41440

   (47) https://bugs.python.org/issue?@action=redirect&bpo=41316

   (48) https://bugs.python.org/issue?@action=redirect&bpo=41384

   (49) https://bugs.python.org/issue?@action=redirect&bpo=41317

   (50) https://bugs.python.org/issue?@action=redirect&bpo=41364

   (51) https://bugs.python.org/issue?@action=redirect&bpo=35328

   (52) https://bugs.python.org/issue?@action=redirect&bpo=41341

   (53) https://bugs.python.org/issue?@action=redirect&bpo=41344

   (54) https://bugs.python.org/issue?@action=redirect&bpo=41333

   (55) https://bugs.python.org/issue?@action=redirect&bpo=41288

   (56) https://bugs.python.org/issue?@action=redirect&bpo=39017

   (57) https://www.cve.org/CVERecord?id=CVE-2019-20907

   (58) https://bugs.python.org/issue?@action=redirect&bpo=41273

   (59) https://bugs.python.org/issue?@action=redirect&bpo=41235

   (60) https://bugs.python.org/issue?@action=redirect&bpo=41207

   (61) https://bugs.python.org/issue?@action=redirect&bpo=29727

   (62) https://bugs.python.org/issue?@action=redirect&bpo=39168

   (63) https://bugs.python.org/issue?@action=redirect&bpo=41194

   (64) https://bugs.python.org/issue?@action=redirect&bpo=41195

   (65) https://bugs.python.org/issue?@action=redirect&bpo=41193

   (66) https://bugs.python.org/issue?@action=redirect&bpo=41182

   (67) https://bugs.python.org/issue?@action=redirect&bpo=41161

   (68) https://bugs.python.org/issue?@action=redirect&bpo=40874

   (69) https://bugs.python.org/issue?@action=redirect&bpo=41138

   (70) https://bugs.python.org/issue?@action=redirect&bpo=31082

   (71) https://bugs.python.org/issue?@action=redirect&bpo=40521

   (72) https://bugs.python.org/issue?@action=redirect&bpo=31938

   (73) https://bugs.python.org/issue?@action=redirect&bpo=41068

   (74) https://bugs.python.org/issue?@action=redirect&bpo=41058

   (75) https://bugs.python.org/issue?@action=redirect&bpo=41056

   (76) https://bugs.python.org/issue?@action=redirect&bpo=41056

   (77) https://bugs.python.org/issue?@action=redirect&bpo=41056

   (78) https://bugs.python.org/issue?@action=redirect&bpo=41048

   (79) https://bugs.python.org/issue?@action=redirect&bpo=41043

   (80) https://bugs.python.org/issue?@action=redirect&bpo=41025

   (81) https://bugs.python.org/issue?@action=redirect&bpo=35018

   (82) https://bugs.python.org/issue?@action=redirect&bpo=41002

   (83) https://bugs.python.org/issue?@action=redirect&bpo=40448

   (84) https://bugs.python.org/issue?@action=redirect&bpo=40967

   (85) https://bugs.python.org/issue?@action=redirect&bpo=40924

   (86) https://bugs.python.org/issue?@action=redirect&bpo=40955

   (87) https://bugs.python.org/issue?@action=redirect&bpo=40855

   (88) https://bugs.python.org/issue?@action=redirect&bpo=40939

   (89) https://bugs.python.org/issue?@action=redirect&bpo=23427

   (90) https://bugs.python.org/issue?@action=redirect&bpo=33689

   (91) https://bugs.python.org/issue?@action=redirect&bpo=40884

   (92) https://bugs.python.org/issue?@action=redirect&bpo=40876

   (93) https://bugs.python.org/issue?@action=redirect&bpo=39791

   (94) https://bugs.python.org/issue?@action=redirect&bpo=40807

   (95) https://bugs.python.org/issue?@action=redirect&bpo=32604

   (96) https://bugs.python.org/issue?@action=redirect&bpo=39791

   (97) https://bugs.python.org/issue?@action=redirect&bpo=39314

   (98) https://bugs.python.org/issue?@action=redirect&bpo=17005

   (99) https://bugs.python.org/issue?@action=redirect&bpo=40834

   (100) https://bugs.python.org/issue?@action=redirect&bpo=40755

   (101) https://bugs.python.org/issue?@action=redirect&bpo=26407

   (102) https://bugs.python.org/issue?@action=redirect&bpo=39384

   (103) https://bugs.python.org/issue?@action=redirect&bpo=40744

   (104) https://bugs.python.org/issue?@action=redirect&bpo=40777

   (105) https://bugs.python.org/issue?@action=redirect&bpo=38488

   (106) https://bugs.python.org/issue?@action=redirect&bpo=40792

   (107) https://bugs.python.org/issue?@action=redirect&bpo=40767

   (108) https://bugs.python.org/issue?@action=redirect&bpo=40791

   (109) https://bugs.python.org/issue?@action=redirect&bpo=40795

   (110) https://bugs.python.org/issue?@action=redirect&bpo=16995

   (111) https://bugs.python.org/issue?@action=redirect&bpo=30008

   (112) https://bugs.python.org/issue?@action=redirect&bpo=30064

   (113) https://bugs.python.org/issue?@action=redirect&bpo=40759

   (114) https://bugs.python.org/issue?@action=redirect&bpo=40756

   (115) https://bugs.python.org/issue?@action=redirect&bpo=37129

   (116) https://bugs.python.org/issue?@action=redirect&bpo=40737

   (117) https://bugs.python.org/issue?@action=redirect&bpo=40726

   (118) https://bugs.python.org/issue?@action=redirect&bpo=40698

   (119) https://bugs.python.org/issue?@action=redirect&bpo=40695

   (120) https://bugs.python.org/issue?@action=redirect&bpo=9216

   (121) https://bugs.python.org/issue?@action=redirect&bpo=40614

   (122) https://bugs.python.org/issue?@action=redirect&bpo=40626

   (123) https://bugs.python.org/issue?@action=redirect&bpo=25920

   (124) https://bugs.python.org/issue?@action=redirect&bpo=40671

   (125) https://peps.python.org/pep-0489/

   (126) https://bugs.python.org/issue?@action=redirect&bpo=32309

   (127) https://bugs.python.org/issue?@action=redirect&bpo=36543

   (128) https://bugs.python.org/issue?@action=redirect&bpo=40611

   (129) https://bugs.python.org/issue?@action=redirect&bpo=39881

   (130) https://bugs.python.org/issue?@action=redirect&bpo=13097

   (131) https://bugs.python.org/issue?@action=redirect&bpo=39385

   (132) https://bugs.python.org/issue?@action=redirect&bpo=23082

   (133) https://bugs.python.org/issue?@action=redirect&bpo=40318

   (134) https://bugs.python.org/issue?@action=redirect&bpo=40105

   (135) https://bugs.python.org/issue?@action=redirect&bpo=40084

   (136) https://bugs.python.org/issue?@action=redirect&bpo=31122

   (137) https://bugs.python.org/issue?@action=redirect&bpo=39728

   (138) https://bugs.python.org/issue?@action=redirect&bpo=39244

   (139) https://bugs.python.org/issue?@action=redirect&bpo=39040

   (140) https://bugs.python.org/issue?@action=redirect&bpo=38731

   (141) https://bugs.python.org/issue?@action=redirect&bpo=35714

   (142) https://bugs.python.org/issue?@action=redirect&bpo=38144

   (143) https://bugs.python.org/issue?@action=redirect&bpo=26543

   (144) https://bugs.python.org/issue?@action=redirect&bpo=12178

   (145) https://bugs.python.org/issue?@action=redirect&bpo=36290

   (146) https://bugs.python.org/issue?@action=redirect&bpo=33944

   (147) https://bugs.python.org/issue?@action=redirect&bpo=35078

   (148) https://bugs.python.org/issue?@action=redirect&bpo=29620

   (149) https://bugs.python.org/issue?@action=redirect&bpo=31844

   (150) https://bugs.python.org/issue?@action=redirect&bpo=34226

   (151) https://bugs.python.org/issue?@action=redirect&bpo=33660

   (152) https://bugs.python.org/issue?@action=redirect&bpo=28557

   (153) https://bugs.python.org/issue?@action=redirect&bpo=26680

   (154) https://bugs.python.org/issue?@action=redirect&bpo=26680


File: python.info,  Node: Documentation<42>,  Next: Tests<45>,  Prev: Library<126>,  Up: Python 3 10 0 alpha 1

1.23.51.32 Documentation
........................

   - bpo-41428(1): Add documentation for PEP 604(2) (Allow writing union
     types as ‘X | Y’).

   - bpo-41774(3): In Programming FAQ “Sequences (Tuples/Lists)”
     section, add “How do you remove multiple items from a list”.

   - bpo-35293(4): Fix RemovedInSphinx40Warning when building the
     documentation.  Patch by Donghee Na.

   - bpo-37149(5): Change Shipman tkinter doc link from archive.org to
     TkDocs.  (The doc has been removed from the NMT server.)  The new
     link responds much faster and includes a short explanatory note.

   - bpo-41726(6): Update the refcounts info of
     ‘PyType_FromModuleAndSpec’.

   - bpo-41624(7): Fix the signature of *note typing.Coroutine: 1ad8.

   - bpo-40204(8): Enable Sphinx 3.2 ‘c_allow_pre_v3’ option and disable
     ‘c_warn_on_allowed_pre_v3’ option to make the documentation
     compatible with Sphinx 2 and Sphinx 3.

   - bpo-41045(9): Add documentation for debug feature of f-strings.

   - bpo-41314(10): Changed the release when ‘from __future__ import
     annotations’ becomes the default from ‘4.0’ to ‘3.10’ (following a
     change in PEP 563).

   - bpo-40979(11): Refactored typing.rst, arranging more than 70
     classes, functions, and decorators into new sub-sections.

   - bpo-40552(12): Fix in tutorial section 4.2.  Code snippet is now
     correct.

   - bpo-39883(13): Make code, examples, and recipes in the Python
     documentation be licensed under the more permissive BSD0 license in
     addition to the existing Python 2.0 license.

   - bpo-37703(14): Updated Documentation to comprehensively elaborate
     on the behaviour of gather.cancel()

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41428

   (2) https://peps.python.org/pep-0604/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41774

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35293

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37149

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41726

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41624

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40204

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41045

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41314

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40979

   (12) https://bugs.python.org/issue?@action=redirect&bpo=40552

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39883

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37703


File: python.info,  Node: Tests<45>,  Next: Build<49>,  Prev: Documentation<42>,  Up: Python 3 10 0 alpha 1

1.23.51.33 Tests
................

   - bpo-41939(1): Fix test_site.test_license_exists_at_url(): call
     ‘urllib.request.urlcleanup()’ to reset the global
     ‘urllib.request._opener’.  Patch by Victor Stinner.

   - bpo-41731(2): Make test_cmd_line_script pass with option ‘-vv’.

   - bpo-41602(3): Add tests for SIGINT handling in the runpy module.

   - bpo-41521(4): *note test.support: e4.: Rename ‘blacklist’ parameter
     of *note check__all__(): 1ada. to ‘not_exported’.

   - bpo-41477(5): Make ctypes optional in test_genericalias.

   - bpo-41085(6): Fix integer overflow in the *note
     array.array.index(): 7e5. method on 64-bit Windows for index larger
     than ‘2**31’.

   - bpo-41069(7): ‘test.support.TESTFN’ and the current directory for
     tests when run via ‘test.regrtest’ contain now non-ascii characters
     if possible.

   - bpo-38377(8): On Linux, skip tests using multiprocessing if the
     current user cannot create a file in ‘/dev/shm/’ directory.  Add
     the *note skip_if_broken_multiprocessing_synchronize(): 1adb.
     function to the *note test.support: e4. module.

   - bpo-41009(9): Fix use of
     ‘support.require_{linux|mac|freebsd}_version()’ decorators as class
     decorator.

   - bpo-41003(10): Fix ‘test_copyreg’ when ‘numpy’ is installed:
     ‘test.pickletester’ now saves/restores warnings filters when
     importing ‘numpy’, to ignore filters installed by ‘numpy’.

   - bpo-40964(11): Disable remote *note imaplib: 74. tests, host
     cyrus.andrew.cmu.edu is blocking incoming connections.

   - bpo-40927(12): Fix test_binhex when run twice: it now uses
     import_fresh_module() to ensure that it raises DeprecationWarning
     each time.

   - bpo-17258(13): Skip some *note multiprocessing: 94. tests when MD5
     hash digest is blocked.

   - bpo-31904(14): Increase LOOPBACK_TIMEOUT to 10 for VxWorks RTOS.

   - bpo-38169(15): Increase code coverage for SharedMemory and
     ShareableList

   - bpo-34401(16): Make test_gdb properly run on HP-UX. Patch by
     Michael Osipov.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41939

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41731

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41602

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41521

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41477

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41085

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41069

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38377

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41009

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41003

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40964

   (12) https://bugs.python.org/issue?@action=redirect&bpo=40927

   (13) https://bugs.python.org/issue?@action=redirect&bpo=17258

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (15) https://bugs.python.org/issue?@action=redirect&bpo=38169

   (16) https://bugs.python.org/issue?@action=redirect&bpo=34401


File: python.info,  Node: Build<49>,  Next: Windows<42>,  Prev: Tests<45>,  Up: Python 3 10 0 alpha 1

1.23.51.34 Build
................

   - bpo-38249(1): Update *note Py_UNREACHABLE: bd3. to use
     __builtin_unreachable() if only the compiler is able to use it.
     Patch by Donghee Na.

   - bpo-41617(2): Fix ‘pycore_bitutils.h’ header file to support old
     clang versions: ‘__builtin_bswap16()’ is not available in LLVM
     clang 3.0.

   - bpo-40204(3): Pin Sphinx version to 2.3.1 in ‘Doc/Makefile’.

   - bpo-36020(4): The C99 functions ‘snprintf()’ and ‘vsnprintf()’ are
     now required to build Python.

   - bpo-40684(5): ‘make install’ now uses the ‘PLATLIBDIR’ variable for
     the destination ‘lib-dynload/’ directory when ‘./configure
     --with-platlibdir’ is used.

   - bpo-40683(6): Fixed an issue where the *note zoneinfo: 134. module
     and its tests were not included when Python is installed with
     ‘make’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38249

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41617

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40204

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36020

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40684

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40683


File: python.info,  Node: Windows<42>,  Next: macOS<34>,  Prev: Build<49>,  Up: Python 3 10 0 alpha 1

1.23.51.35 Windows
..................

   - bpo-41744(1): Fixes automatic import of props file when using the
     Nuget package.

   - bpo-41627(2): The user site directory for 32-bit now includes a
     ‘-32’ suffix to distinguish it from the 64-bit interpreter’s
     directory.

   - bpo-41526(3): Fixed layout of final page of the installer by
     removing the special thanks to Mark Hammond (with his permission).

   - bpo-41492(4): Fixes the description that appears in UAC prompts.

   - bpo-40948(5): Improve post-install message to direct people to the
     “py” command.

   - bpo-41412(6): The installer will now fail to install on Windows 7
     and Windows 8.  Further, the UCRT dependency is now always
     downloaded on demand.

   - bpo-40741(7): Update Windows release to include SQLite 3.32.3.

   - bpo-41142(8): ‘msilib’ now supports creating CAB files with
     non-ASCII file path and adding files with non-ASCII file path to
     them.

   - bpo-41074(9): Fixed support of non-ASCII names in functions
     ‘msilib.OpenDatabase()’ and ‘msilib.init_database()’ and non-ASCII
     SQL in method ‘msilib.Database.OpenView()’.

   - bpo-41039(10): Stable ABI redirection DLL (python3.dll) now uses
     ‘#pragma comment(linker)’ for re-exporting.

   - bpo-40164(11): Updates Windows OpenSSL to 1.1.1g

   - bpo-39631(12): Changes the registered MIME type for ‘.py’ files on
     Windows to ‘text/x-python’ instead of ‘text/plain’.

   - bpo-40677(13): Manually define IO_REPARSE_TAG_APPEXECLINK in case
     some old Windows SDK doesn’t have it.

   - bpo-37556(14): Extend py.exe help to mention overrides via venv,
     shebang, environmental variables & ini files.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41744

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41627

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41526

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41492

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40948

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41412

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40741

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41142

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41074

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41039

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40164

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39631

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40677

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37556


File: python.info,  Node: macOS<34>,  Next: IDLE<30>,  Prev: Windows<42>,  Up: Python 3 10 0 alpha 1

1.23.51.36 macOS
................

   - bpo-41557(1): Update macOS installer to use SQLite 3.33.0.

   - bpo-39580(2): Avoid opening Finder window if running installer from
     the command line.  Patch contributed by Rick Heil.

   - bpo-41100(3): Fix configure error when building on macOS 11.  Note
     that the current Python release was released shortly after the
     first developer preview of macOS 11 (Big Sur); there are other
     known issues with building and running on the developer preview.
     Big Sur is expected to be fully supported in a future bugfix
     release of Python 3.8.x and with 3.9.0.

   - bpo-40741(4): Update macOS installer to use SQLite 3.32.3.

   - bpo-41005(5): fixed an XDG settings issue not allowing macos to
     open browser in webbrowser.py

   - bpo-40741(6): Update macOS installer to use SQLite 3.32.2.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41557

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39580

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41100

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40741

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41005

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40741


File: python.info,  Node: IDLE<30>,  Next: C API<44>,  Prev: macOS<34>,  Up: Python 3 10 0 alpha 1

1.23.51.37 IDLE
...............

   - bpo-41775(1): Use ‘IDLE Shell’ as shell title

   - bpo-35764(2): Rewrite the Calltips doc section.

   - bpo-40181(3): In calltips, stop reminding that ‘/’ marks the end of
     positional-only arguments.

   - bpo-41468(4): Improve IDLE run crash error message (which users
     should never see).

   - bpo-41373(5): Save files loaded with no line ending, as when blank,
     or different line endings, by setting its line ending to the system
     default.  Fix regression in 3.8.4 and 3.9.0b4.

   - bpo-41300(6): Save files with non-ascii chars.  Fix regression
     released in 3.9.0b4 and 3.8.4.

   - bpo-37765(7): Add keywords to module name completion list.  Rewrite
     Completions section of IDLE doc.

   - bpo-41152(8): The encoding of ‘stdin’, ‘stdout’ and ‘stderr’ in
     IDLE is now always UTF-8.

   - bpo-41144(9): Make Open Module open a special module such as
     os.path.

   - bpo-39885(10): Make context menu Cut and Copy work again when
     right-clicking within a selection.

   - bpo-40723(11): Make test_idle pass when run after import.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41775

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35764

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40181

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41468

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41373

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41300

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37765

   (8) https://bugs.python.org/issue?@action=redirect&bpo=41152

   (9) https://bugs.python.org/issue?@action=redirect&bpo=41144

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39885

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40723


File: python.info,  Node: C API<44>,  Prev: IDLE<30>,  Up: Python 3 10 0 alpha 1

1.23.51.38 C API
................

   - bpo-41936(1): Removed undocumented macros ‘Py_ALLOW_RECURSION’ and
     ‘Py_END_ALLOW_RECURSION’ and the ‘recursion_critical’ field of the
     *note PyInterpreterState: 8c5. structure.

   - bpo-41692(2): The ‘PyUnicode_InternImmortal()’ function is now
     deprecated and will be removed in Python 3.12: use *note
     PyUnicode_InternInPlace(): 8b9. instead.  Patch by Victor Stinner.

   - bpo-41842(3): Add *note PyCodec_Unregister(): 89e. function to
     unregister a codec search function.

   - bpo-41834(4): Remove the ‘_Py_CheckRecursionLimit’ variable: it has
     been replaced by ‘ceval.recursion_limit’ of the *note
     PyInterpreterState: 8c5. structure.  Patch by Victor Stinner.

   - bpo-41689(5): Types created with *note PyType_FromSpec(): 580. now
     make any signature in their ‘tp_doc’ slot accessible from
     ‘__text_signature__’.

   - bpo-41524(6): Fix bug in *note PyOS_mystrnicmp(): 1ae1. and *note
     PyOS_mystricmp(): 1ae2. that incremented pointers beyond the end of
     a string.

   - bpo-41324(7): Add a minimal decimal capsule API. The API supports
     fast conversions between Decimals up to 38 digits and their triple
     representation as a C struct.

   - bpo-30155(8): Add *note PyDateTime_DATE_GET_TZINFO(): 89c. and
     *note PyDateTime_TIME_GET_TZINFO(): 89d. macros for accessing the
     ‘tzinfo’ attributes of *note datetime.datetime: 1cc. and *note
     datetime.time: 1ce. objects.

   - bpo-40170(9): Revert *note PyType_HasFeature(): 1ae3. change: it
     reads again directly the *note PyTypeObject.tp_flags: 1a18. member
     when the limited C API is not used, rather than always calling
     *note PyType_GetFlags(): 1ae4. which hides implementation details.

   - bpo-41123(10): Remove ‘PyUnicode_AsUnicodeCopy’.

   - bpo-41123(11): Removed ‘PyLong_FromUnicode()’.

   - bpo-41123(12): Removed ‘PyUnicode_GetMax()’.

   - bpo-41123(13): Removed ‘Py_UNICODE_str*’ functions manipulating
     ‘Py_UNICODE*’ strings.

   - bpo-41103(14): ‘PyObject_AsCharBuffer()’,
     ‘PyObject_AsReadBuffer()’, ‘PyObject_CheckReadBuffer()’, and
     ‘PyObject_AsWriteBuffer()’ are removed.  Please migrate to new
     buffer protocol; *note PyObject_GetBuffer(): 39c. and *note
     PyBuffer_Release(): 39d.

   - bpo-36346(15): Raises DeprecationWarning for
     ‘PyUnicode_FromUnicode(NULL, size)’ and
     ‘PyUnicode_FromStringAndSize(NULL, size)’ with ‘size > 0’.

   - bpo-36346(16): Mark ‘Py_UNICODE_COPY’, ‘Py_UNICODE_FILL’,
     ‘PyUnicode_WSTR_LENGTH’, ‘PyUnicode_FromUnicode’,
     ‘PyUnicode_AsUnicode’, and ‘PyUnicode_AsUnicodeAndSize’ as
     deprecated in C. Remove ‘Py_UNICODE_MATCH’ which was deprecated and
     broken since Python 3.3.

   - bpo-40989(17): The *note PyObject_INIT(): 1ae5. and *note
     PyObject_INIT_VAR(): 1ae6. macros become aliases to, respectively,
     *note PyObject_Init(): a79. and *note PyObject_InitVar(): 1ae7.
     functions.

   - bpo-36020(18): On Windows, ‘#include "pyerrors.h"’ no longer
     defines ‘snprintf’ and ‘vsnprintf’ macros.

   - bpo-40943(19): The ‘PY_SSIZE_T_CLEAN’ macro must now be defined to
     use *note PyArg_ParseTuple(): 574. and *note Py_BuildValue(): 8af.
     formats which use ‘#’: ‘es#’, ‘et#’, ‘s#’, ‘u#’, ‘y#’, ‘z#’, ‘U#’
     and ‘Z#’.  See *note Parsing arguments and building values: 8b0.
     and the PEP 353(20).

   - bpo-40910(21): Export explicitly the *note Py_GetArgcArgv(): 1ae8.
     function to the C API and document the function.  Previously, it
     was exported implicitly which no longer works since Python is built
     with ‘-fvisibility=hidden’.

   - bpo-40724(22): Allow defining buffer slots in type specs.

   - bpo-40679(23): Fix a ‘_PyEval_EvalCode()’ crash if 'qualname'
     argument is NULL.

   - bpo-40839(24): Calling *note PyDict_GetItem(): 38a. without *note
     GIL: 159. held had been allowed for historical reason.  It is no
     longer allowed.

   - bpo-40826(25): *note PyOS_InterruptOccurred(): 1ae9. now fails with
     a fatal error if it is called with the GIL released.

   - bpo-40792(26): The result of *note PyNumber_Index(): 89a. now
     always has exact type *note int: 257.  Previously, the result could
     have been an instance of a subclass of ‘int’.

   - bpo-39573(27): Convert *note Py_REFCNT(): 8b1. and *note Py_SIZE():
     785. macros to static inline functions.  They cannot be used as
     l-value anymore: use *note Py_SET_REFCNT(): 8b2. and *note
     Py_SET_SIZE(): 786. to set an object reference count and size.
     This change is backward incompatible on purpose, to prepare the C
     API for an opaque *note PyObject: 33a. structure.

   - bpo-40703(28): The PyType_FromSpec*() functions no longer overwrite
     the type’s “__module__” attribute if it is set via “Py_tp_members”
     or “Py_tp_getset”.

   - bpo-39583(29): Remove superfluous “extern C” declarations from
     ‘Include/cpython/*.h’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=41936

   (2) https://bugs.python.org/issue?@action=redirect&bpo=41692

   (3) https://bugs.python.org/issue?@action=redirect&bpo=41842

   (4) https://bugs.python.org/issue?@action=redirect&bpo=41834

   (5) https://bugs.python.org/issue?@action=redirect&bpo=41689

   (6) https://bugs.python.org/issue?@action=redirect&bpo=41524

   (7) https://bugs.python.org/issue?@action=redirect&bpo=41324

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30155

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (10) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (11) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (12) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (13) https://bugs.python.org/issue?@action=redirect&bpo=41123

   (14) https://bugs.python.org/issue?@action=redirect&bpo=41103

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36346

   (17) https://bugs.python.org/issue?@action=redirect&bpo=40989

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36020

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40943

   (20) https://peps.python.org/pep-0353/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40910

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40724

   (23) https://bugs.python.org/issue?@action=redirect&bpo=40679

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40839

   (25) https://bugs.python.org/issue?@action=redirect&bpo=40826

   (26) https://bugs.python.org/issue?@action=redirect&bpo=40792

   (27) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (28) https://bugs.python.org/issue?@action=redirect&bpo=40703

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39583


File: python.info,  Node: Python 3 9 0 beta 1,  Next: Python 3 9 0 alpha 6,  Prev: Python 3 10 0 alpha 1,  Up: Changelog

1.23.52 Python 3.9.0 beta 1
---------------------------

'Release date: 2020-05-19'

* Menu:

* Security: Security<34>.
* Core and Builtins: Core and Builtins<125>.
* Library: Library<127>.
* Documentation: Documentation<43>.
* Tests: Tests<46>.
* Build: Build<50>.
* Windows: Windows<43>.
* macOS: macOS<35>.
* Tools/Demos: Tools/Demos<23>.
* C API: C API<45>.


File: python.info,  Node: Security<34>,  Next: Core and Builtins<125>,  Up: Python 3 9 0 beta 1

1.23.52.1 Security
..................

   - bpo-40501(1): *note uuid: 110. no longer uses *note ctypes: 2a. to
     load ‘libuuid’ or ‘rpcrt4.dll’ at runtime.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40501


File: python.info,  Node: Core and Builtins<125>,  Next: Library<127>,  Prev: Security<34>,  Up: Python 3 9 0 beta 1

1.23.52.2 Core and Builtins
...........................

   - bpo-40663(1): Correctly generate annotations where parentheses are
     omitted but required (e.g: ‘Type[(str, int, *other))]’.

   - bpo-40596(2): Fixed *note str.isidentifier(): 1aed. for
     non-canonicalized strings containing non-BMP characters on Windows.

   - bpo-40593(3): Improved syntax errors for invalid characters in
     source code.

   - bpo-40585(4): Fixed a bug when using *note
     codeop.compile_command(): 18f8. that was causing exceptions to be
     swallowed with the new parser.  Patch by Pablo Galindo

   - bpo-40566(5): Apply PEP 573(6) to *note abc: 4.

   - bpo-40502(7): Initialize ‘n->n_col_offset’.  (Patch by Joannah
     Nanjekye)

   - bpo-40527(8): Fix command line argument parsing: no longer write
     errors multiple times into stderr.

   - bpo-1635741(9): Port *note errno: 57. to multiphase initialization
     ( PEP 489(10)).

   - bpo-40523(11): Add pass-throughs for *note hash(): 5ee. and *note
     reversed(): 86c. to *note weakref.proxy: a5f. objects.  Patch by
     Pablo Galindo.

   - bpo-1635741(12): Port *note syslog: dc. to multiphase
     initialization ( PEP 489(13)).

   - bpo-40246(14): Reporting a specialised error message for invalid
     string prefixes, which was introduced in bpo-40246(15), is being
     reverted due to backwards compatibility concerns for strings that
     immediately follow a reserved keyword without whitespace between
     them.  Constructs like ‘bg="#d00" if clear else"#fca"’ were failing
     to parse, which is not an acceptable breakage on such short notice.

   - bpo-40417(16): Fix imp module deprecation warning when
     PyImport_ReloadModule is called.  Patch by Robert Rouhani.

   - bpo-40408(17): Fixed support of nested type variables in
     GenericAlias (e.g.  ‘list[list[T]]’).

   - bpo-1635741(18): Port _stat module to multiphase initialization (
     PEP 489(19)).

   - bpo-29587(20): Enable implicit exception chaining when calling
     *note generator.throw(): 4fb.

   - bpo-40328(21): Add tools for generating mappings headers for
     CJKCodecs.

   - bpo-40228(22): Setting frame.f_lineno is now robust w.r.t.  changes
     in the source-to-bytecode compiler

   - bpo-38880(23): Added the ability to list interpreters associated
     with channel ends in the internal subinterpreters module.

   - bpo-37986(24): Improve performance of *note PyLong_FromDouble():
     94c. for values that fit into long.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40663

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40596

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40593

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40585

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40566

   (6) https://peps.python.org/pep-0573/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40502

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40527

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (10) https://peps.python.org/pep-0489/

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40523

   (12) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (13) https://peps.python.org/pep-0489/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=40246

   (15) https://bugs.python.org/issue?@action=redirect&bpo=40246

   (16) https://bugs.python.org/issue?@action=redirect&bpo=40417

   (17) https://bugs.python.org/issue?@action=redirect&bpo=40408

   (18) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (19) https://peps.python.org/pep-0489/

   (20) https://bugs.python.org/issue?@action=redirect&bpo=29587

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40328

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40228

   (23) https://bugs.python.org/issue?@action=redirect&bpo=38880

   (24) https://bugs.python.org/issue?@action=redirect&bpo=37986


File: python.info,  Node: Library<127>,  Next: Documentation<43>,  Prev: Core and Builtins<125>,  Up: Python 3 9 0 beta 1

1.23.52.3 Library
.................

   - bpo-40662(1): Fixed *note ast.get_source_segment(): 9e3. for ast
     nodes that have incomplete location information.  Patch by Irit
     Katriel.

   - bpo-40665(2): Convert *note bisect: 11. to use Argument Clinic.

   - bpo-40536(3): Added the *note available_timezones(): 1aef. function
     to the *note zoneinfo: 134. module.  Patch by Paul Ganssle.

   - bpo-40645(4): The *note hmac.HMAC: b57. exposes internal
     implementation details.  The attributes ‘digest_cons’, ‘inner’, and
     ‘outer’ are deprecated and will be removed in the future.

   - bpo-40645(5): The internal module ‘_hashlib’ wraps and exposes
     OpenSSL’s HMAC API. The new code will be used in Python 3.10 after
     the internal implementation details of the pure Python HMAC module
     are no longer part of the public API.

   - bpo-40637(6): Builtin hash modules can now be disabled or
     selectively enabled with ‘configure
     --with-builtin-hashlib-hashes=sha3,blake1’ or
     ‘--without-builtin-hashlib-hashes’.

   - bpo-37630(7): The *note hashlib: 68. module can now use SHA3 hashes
     and SHAKE XOF from OpenSSL when available.

   - bpo-40479(8): The *note hashlib: 68. now compiles with OpenSSL
     3.0.0-alpha2.

   - bpo-40257(9): Revert changes to *note inspect.getdoc(): a05.

   - bpo-40607(10): When cancelling a task due to timeout, *note
     asyncio.wait_for(): 602. will now propagate the exception if an
     error happens during cancellation.  Patch by Roman Skurikhin.

   - bpo-40612(11): Fix edge cases in SyntaxError formatting.  If the
     offset is <= 0, no caret is printed.  If the offset is > line
     length, the caret is printed pointing just after the last
     character.

   - bpo-40597(12): If text content lines are longer than
     policy.max_line_length, always use a content-encoding to make sure
     they are wrapped.

   - bpo-40571(13): Added functools.cache() as a simpler, more
     discoverable way to access the unbounded cache variant of
     lru_cache(maxsize=None).

   - bpo-40503(14): PEP 615(15), the *note zoneinfo: 134. module.  Adds
     support for the IANA time zone database.

   - bpo-40397(16): Removed attributes ‘__args__’ and ‘__parameters__’
     from special generic aliases like ‘typing.List’ (not subscripted).

   - bpo-40549(17): Convert posixmodule.c (“posix” or “nt” module) to
     the multiphase initialization (PEP 489).

   - bpo-31033(18): Add a ‘msg’ argument to ‘Future.cancel()’ and
     ‘Task.cancel()’.

   - bpo-40541(19): Added an optional 'counts' parameter to
     random.sample().

   - bpo-40515(20): The *note ssl: d0. and *note hashlib: 68. modules
     now actively check that OpenSSL is build with thread support.
     Python 3.7.0 made thread support mandatory and no longer works
     safely with a no-thread builds.

   - bpo-31033(21): When a *note asyncio.Task: 1be. is cancelled, the
     exception traceback now chains all the way back to where the task
     was first interrupted.

   - bpo-40504(22): *note functools.lru_cache(): 9fa. objects can now be
     the targets of weakrefs.

   - bpo-40559(23): Fix possible memory leak in the C implementation of
     *note asyncio.Task: 1be.

   - bpo-40480(24): ‘fnmatch.fnmatch()’ could take exponential time in
     the presence of multiple ‘*’ pattern characters.  This was repaired
     by generating more elaborate regular expressions to avoid futile
     backtracking.

   - bpo-40495(25): *note compileall: 20. is now able to use hardlinks
     to prevent duplicates in a case when ‘.pyc’ files for different
     optimization levels have the same content.

   - bpo-40457(26): The ssl module now support OpenSSL builds without
     TLS 1.0 and 1.1 methods.

   - bpo-40355(27): Improve error reporting in *note ast.literal_eval():
     c38. in the presence of malformed *note ast.Dict: 1af0. nodes
     instead of silently ignoring any non-conforming elements.  Patch by
     Curtis Bucher.

   - bpo-40465(28): Deprecated the optional 'random' argument to
     'random.shuffle()'.

   - bpo-40459(29): *note platform.win32_ver(): 1af1. now produces
     correct 'ptype' strings instead of empty strings.

   - bpo-39435(30): The first argument of *note pickle.loads(): d39. is
     now positional-only.

   - bpo-39305(31): Update ‘nntplib’ to merge ‘nntplib.NNTP’ and
     ‘nntplib._NNTPBase’.  Patch by Donghee Na.

   - bpo-32494(32): Update *note dbm.gnu: 33. to use gdbm_count if
     possible when calling *note len(): 631.  Patch by Donghee Na.

   - bpo-40453(33): Add ‘isolated=True’ keyword-only parameter to
     ‘_xxsubinterpreters.create()’.  An isolated subinterpreter cannot
     spawn threads, spawn a child process or call ‘os.fork()’.

   - bpo-40286(34): Remove ‘_random.Random.randbytes()’: the C
     implementation of ‘randbytes()’.  Implement the method in Python to
     ease subclassing: ‘randbytes()’ now directly reuses
     ‘getrandbits()’.

   - bpo-40394(35): Added default arguments to *note
     difflib.SequenceMatcher.find_longest_match(): 1af2.

   - bpo-39995(36): Fix a race condition in
     concurrent.futures._ThreadWakeup: access to _ThreadWakeup is now
     protected with the shutdown lock.

   - bpo-30966(37): ‘Process.shutdown(wait=True)’ of *note
     concurrent.futures: 21. now closes explicitly the result queue.

   - bpo-30966(38): Add a new *note close(): 91e. method to the *note
     SimpleQueue: 91d. class to explicitly close the queue.

   - bpo-39966(39): Revert bpo-25597(40).  *note
     unittest.mock.MagicMock: ec3. with wraps’ set uses default return
     values for magic methods.

   - bpo-39791(41): Added ‘files()’ function to importlib.resources with
     support for subdirectories in package data, matching backport in
     importlib_resources 1.5.

   - bpo-40375(42): *note imaplib.IMAP4.unselect(): 910. is added.
     Patch by Donghee Na.

   - bpo-40389(43): ‘repr()’ now returns ‘typing.Optional[T]’ when
     called for ‘typing.Union’ of two types, one of which is ‘NoneType’.

   - bpo-40291(44): Add support for CAN_J1939 sockets (available on
     Linux 5.4+)

   - bpo-40273(45): *note types.MappingProxyType: 470. is now
     reversible.

   - bpo-39075(46): The repr for *note types.SimpleNamespace: 1d1. is
     now insertion ordered rather than alphabetical.

   - bpo-40192(47): On AIX, *note thread_time(): 940. is now implemented
     with ‘thread_cputime()’ which has nanosecond resolution, rather
     than ‘clock_gettime(CLOCK_THREAD_CPUTIME_ID)’ which has a
     resolution of 10 milliseconds.  Patch by Batuhan Taskaya.

   - bpo-40025(48): Raise TypeError when _generate_next_value_ is
     defined after members.  Patch by Ethan Onstott.

   - bpo-39058(49): In the argparse module, the repr for Namespace() and
     other argument holders now displayed in the order attributes were
     added.  Formerly, it displayed in alphabetical order even though
     argument order is preserved the user visible parts of the module.

   - bpo-24416(50): The ‘isocalendar()’ methods of *note datetime.date:
     1cd. and *note datetime.datetime: 1cc. now return a *note named
     tuple: 651. instead of a *note tuple: 373.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40662

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40665

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40536

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40645

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40645

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40637

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37630

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40479

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40257

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40607

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40612

   (12) https://bugs.python.org/issue?@action=redirect&bpo=40597

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40571

   (14) https://bugs.python.org/issue?@action=redirect&bpo=40503

   (15) https://peps.python.org/pep-0615/

   (16) https://bugs.python.org/issue?@action=redirect&bpo=40397

   (17) https://bugs.python.org/issue?@action=redirect&bpo=40549

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31033

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40541

   (20) https://bugs.python.org/issue?@action=redirect&bpo=40515

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31033

   (22) https://bugs.python.org/issue?@action=redirect&bpo=40504

   (23) https://bugs.python.org/issue?@action=redirect&bpo=40559

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40480

   (25) https://bugs.python.org/issue?@action=redirect&bpo=40495

   (26) https://bugs.python.org/issue?@action=redirect&bpo=40457

   (27) https://bugs.python.org/issue?@action=redirect&bpo=40355

   (28) https://bugs.python.org/issue?@action=redirect&bpo=40465

   (29) https://bugs.python.org/issue?@action=redirect&bpo=40459

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39435

   (31) https://bugs.python.org/issue?@action=redirect&bpo=39305

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32494

   (33) https://bugs.python.org/issue?@action=redirect&bpo=40453

   (34) https://bugs.python.org/issue?@action=redirect&bpo=40286

   (35) https://bugs.python.org/issue?@action=redirect&bpo=40394

   (36) https://bugs.python.org/issue?@action=redirect&bpo=39995

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30966

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30966

   (39) https://bugs.python.org/issue?@action=redirect&bpo=39966

   (40) https://bugs.python.org/issue?@action=redirect&bpo=25597

   (41) https://bugs.python.org/issue?@action=redirect&bpo=39791

   (42) https://bugs.python.org/issue?@action=redirect&bpo=40375

   (43) https://bugs.python.org/issue?@action=redirect&bpo=40389

   (44) https://bugs.python.org/issue?@action=redirect&bpo=40291

   (45) https://bugs.python.org/issue?@action=redirect&bpo=40273

   (46) https://bugs.python.org/issue?@action=redirect&bpo=39075

   (47) https://bugs.python.org/issue?@action=redirect&bpo=40192

   (48) https://bugs.python.org/issue?@action=redirect&bpo=40025

   (49) https://bugs.python.org/issue?@action=redirect&bpo=39058

   (50) https://bugs.python.org/issue?@action=redirect&bpo=24416


File: python.info,  Node: Documentation<43>,  Next: Tests<46>,  Prev: Library<127>,  Up: Python 3 9 0 beta 1

1.23.52.4 Documentation
.......................

   - bpo-34790(1): Add version of removal for explicit passing of coros
     to ‘asyncio.wait()’’s documentation

   - bpo-40561(2): Provide docstrings for webbrowser open functions.

   - bpo-40499(3): Mention that *note asyncio.wait(): 482. requires a
     non-empty set of awaitables.

   - bpo-39705(4): Tutorial example for sorted() in the Loop Techniques
     section is given a better explanation.  Also a new example is
     included to explain sorted()’s basic behavior.

   - bpo-39435(5): Fix an incorrect signature for *note pickle.loads():
     d39. in the docs

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34790

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40561

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40499

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39705

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39435


File: python.info,  Node: Tests<46>,  Next: Build<50>,  Prev: Documentation<43>,  Up: Python 3 9 0 beta 1

1.23.52.5 Tests
...............

   - bpo-40055(1): distutils.tests now saves/restores warnings filters
     to leave them unchanged.  Importing tests imports docutils which
     imports pkg_resources which adds a warnings filter.

   - bpo-40436(2): test_gdb and test.pythoninfo now check gdb command
     exit code.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40055

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40436


File: python.info,  Node: Build<50>,  Next: Windows<43>,  Prev: Tests<46>,  Up: Python 3 9 0 beta 1

1.23.52.6 Build
...............

   - bpo-40653(1): Move _dirnameW out of HAVE_SYMLINK to fix a potential
     compiling issue.

   - bpo-40514(2): Add ‘--with-experimental-isolated-subinterpreters’
     build option to ‘configure’: better isolate subinterpreters,
     experimental build mode.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40653

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40514


File: python.info,  Node: Windows<43>,  Next: macOS<35>,  Prev: Build<50>,  Up: Python 3 9 0 beta 1

1.23.52.7 Windows
.................

   - bpo-40650(1): Include winsock2.h in pytime.c for timeval.

   - bpo-40458(2): Increase reserved stack space to prevent overflow
     crash on Windows.

   - bpo-39148(3): Add IPv6 support to *note asyncio: a. datagram
     endpoints in ProactorEventLoop.  Change the raised exception for
     unknown address families to ValueError as it’s not coming from
     Windows API.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40650

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40458

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39148


File: python.info,  Node: macOS<35>,  Next: Tools/Demos<23>,  Prev: Windows<43>,  Up: Python 3 9 0 beta 1

1.23.52.8 macOS
...............

   - bpo-34956(1): When building Python on macOS from source, ‘_tkinter’
     now links with non-system Tcl and Tk frameworks if they are
     installed in ‘/Library/Frameworks’, as had been the case on older
     releases of macOS. If a macOS SDK is explicitly configured, by
     using ‘--enable-universalsdk=’ or ‘-isysroot’, only the SDK itself
     is searched.  The default behavior can still be overridden with
     ‘--with-tcltk-includes’ and ‘--with-tcltk-libs’.

   - bpo-35569(2): Expose RFC 3542 IPv6 socket options.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34956

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35569


File: python.info,  Node: Tools/Demos<23>,  Next: C API<45>,  Prev: macOS<35>,  Up: Python 3 9 0 beta 1

1.23.52.9 Tools/Demos
.....................

   - bpo-40479(1): Update multissltest helper to test with latest
     OpenSSL 1.0.2, 1.1.0, 1.1.1, and 3.0.0-alpha.

   - bpo-40431(2): Fix a syntax typo in ‘turtledemo’ that now raises a
     ‘SyntaxError’.

   - bpo-40163(3): Fix multissltest tool.  OpenSSL has changed download
     URL for old releases.  The multissltest tool now tries to download
     from current and old download URLs.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40479

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40431

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40163


File: python.info,  Node: C API<45>,  Prev: Tools/Demos<23>,  Up: Python 3 9 0 beta 1

1.23.52.10 C API
................

   - bpo-39465(1): Remove the ‘_PyUnicode_ClearStaticStrings()’ function
     from the C API.

   - bpo-38787(2): Add PyCFunction_CheckExact() macro for exact type
     checks now that we allow subtypes of PyCFunction, as well as
     PyCMethod_CheckExact() and PyCMethod_Check() for the new PyCMethod
     subtype.

   - bpo-40545(3): Declare ‘_PyErr_GetTopmostException()’ with
     ‘PyAPI_FUNC()’ to properly export the function in the C API. The
     function remains private (‘_Py’) prefix.

   - bpo-40412(4): Nullify inittab_copy during finalization, preventing
     future interpreter initializations in an embedded situation from
     crashing.  Patch by Gregory Szorc.

   - bpo-40429(5): The *note PyThreadState_GetFrame(): 791. function now
     returns a strong reference to the frame.

   - bpo-40428(6): Remove the following functions from the C API. Call
     *note PyGC_Collect(): 998. explicitly to free all free lists.

        * ‘PyAsyncGen_ClearFreeLists()’

        * ‘PyContext_ClearFreeList()’

        * ‘PyDict_ClearFreeList()’

        * ‘PyFloat_ClearFreeList()’

        * ‘PyFrame_ClearFreeList()’

        * ‘PyList_ClearFreeList()’

        * ‘PySet_ClearFreeList()’

        * ‘PyTuple_ClearFreeList()’

   - bpo-40421(7): New *note PyFrame_GetBack(): 789. function: get the
     frame next outer frame.

   - bpo-40421(8): New *note PyFrame_GetCode(): 78d. function: return a
     borrowed reference to the frame code.

   - bpo-40217(9): Ensure that instances of types created with *note
     PyType_FromSpecWithBases(): 581. will visit its class object when
     traversing references in the garbage collector (implemented as an
     extension of the provided *note tp_traverse: 781.).  Patch by Pablo
     Galindo.

   - bpo-38787(10): Module C state is now accessible from C-defined heap
     type methods ( PEP 573(11)).  Patch by Marcel Plch and Petr
     Viktorin.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39465

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38787

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40545

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40412

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40429

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40428

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40421

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40217

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38787

   (11) https://peps.python.org/pep-0573/


File: python.info,  Node: Python 3 9 0 alpha 6,  Next: Python 3 9 0 alpha 5,  Prev: Python 3 9 0 beta 1,  Up: Changelog

1.23.53 Python 3.9.0 alpha 6
----------------------------

'Release date: 2020-04-27'

* Menu:

* Security: Security<35>.
* Core and Builtins: Core and Builtins<126>.
* Library: Library<128>.
* Documentation: Documentation<44>.
* Tests: Tests<47>.
* Build: Build<51>.
* Windows: Windows<44>.
* macOS: macOS<36>.
* IDLE: IDLE<31>.
* Tools/Demos: Tools/Demos<24>.
* C API: C API<46>.


File: python.info,  Node: Security<35>,  Next: Core and Builtins<126>,  Up: Python 3 9 0 alpha 6

1.23.53.1 Security
..................

   - bpo-40121(1): Fixes audit events raised on creating a new socket.

   - bpo-39073(2): Disallow CR or LF in email.headerregistry.Address
     arguments to guard against header injection attacks.

   - bpo-39503(3): CVE 2020-8492(4): The *note AbstractBasicAuthHandler:
     1a16. class of the *note urllib.request: 10b. module uses an
     inefficient regular expression which can be exploited by an
     attacker to cause a denial of service.  Fix the regex to prevent
     the catastrophic backtracking.  Vulnerability reported by Ben
     Caller and Matt Schwager.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40121

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39073

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39503

   (4) https://www.cve.org/CVERecord?id=CVE-2020-8492


File: python.info,  Node: Core and Builtins<126>,  Next: Library<128>,  Prev: Security<35>,  Up: Python 3 9 0 alpha 6

1.23.53.2 Core and Builtins
...........................

   - bpo-40313(1): Improve the performance of bytes.hex().

   - bpo-40334(2): Switch to a new parser, based on PEG. For more
     details see PEP 617.  To temporarily switch back to the old parser,
     use ‘-X oldparser’ or ‘PYTHONOLDPARSER=1’.  In Python 3.10 we will
     remove the old parser completely, including the ‘parser’ module
     (already deprecated) and anything that depends on it.

   - bpo-40267(3): Fix the tokenizer to display the correct error
     message, when there is a ‘SyntaxError’ on the last input character
     and no newline follows.  It used to be ‘unexpected EOF while
     parsing’, while it should be ‘invalid syntax’.

   - bpo-39522(4): Correctly unparse explicit ‘u’ prefix for strings
     when postponed evaluation for annotations activated.  Patch by
     Batuhan Taskaya.

   - bpo-40246(5): Report a specialized error message, ‘invalid string
     prefix’, when the tokenizer encounters a string with an invalid
     prefix.

   - bpo-40082(6): Fix the signal handler: it now always uses the main
     interpreter, rather than trying to get the current Python thread
     state.

   - bpo-37388(7): str.encode() and str.decode() no longer check the
     encoding and errors in development mode or in debug mode during
     Python finalization.  The codecs machinery can no longer work on
     very late calls to str.encode() and str.decode().

   - bpo-40077(8): Fix possible refleaks in ‘_json’, memo of
     PyScannerObject should be traversed.

   - bpo-37207(9): Speed up calls to ‘dict()’ by using the PEP 590(10)
     ‘vectorcall’ calling convention.

   - bpo-40141(11): Add column and line information to ‘ast.keyword’
     nodes.  Patch by Pablo Galindo.

   - bpo-1635741(12): Port *note resource: bc. to multiphase
     initialization ( PEP 489(13)).

   - bpo-1635741(14): Port *note math: 8e. to multiphase initialization
     ( PEP 489(15)).

   - bpo-1635741(16): Port _uuid module to multiphase initialization (
     PEP 489(17)).

   - bpo-40077(18): Convert json module to use *note PyType_FromSpec():
     580.

   - bpo-40067(19): Improve the error message for multiple star
     expressions in an assignment.  Patch by Furkan Onder

   - bpo-1635741(20): Port _functools module to multiphase
     initialization (PEP 489).  Patch by Paulo Henrique Silva.

   - bpo-1635741(21): Port operator module to multiphase initialization
     (PEP 489).  Patch by Paulo Henrique Silva.

   - bpo-20526(22): Fix *note PyThreadState_Clear(): 1729.
     ‘PyThreadState.frame’ is a borrowed reference, not a strong
     reference: ‘PyThreadState_Clear()’ must not call
     ‘Py_CLEAR(tstate->frame)’.

   - bpo-1635741(23): Port time module to multiphase initialization (
     PEP 489(24)).  Patch by Paulo Henrique Silva.

   - bpo-1635741(25): Port _weakref extension module to multiphase
     initialization ( PEP 489(26)).

   - bpo-40020(27): Fix a leak and subsequent crash in parsetok.c caused
     by realloc misuse on a rare codepath.

   - bpo-39939(28): Added str.removeprefix and str.removesuffix methods
     and corresponding bytes, bytearray, and collections.UserString
     methods to remove affixes from a string if present.  See PEP
     616(29) for a full description.  Patch by Dennis Sweeney.

   - bpo-39481(30): Implement PEP 585.  This supports list[int],
     tuple[str, …] etc.

   - bpo-32894(31): Support unparsing of infinity numbers in postponed
     annotations.  Patch by Batuhan Taşkaya.

   - bpo-37207(32): Speed up calls to ‘list()’ by using the PEP 590(33)
     ‘vectorcall’ calling convention.  Patch by Mark Shannon.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40313

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40334

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40267

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39522

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40246

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40082

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37388

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40077

   (9) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (10) https://peps.python.org/pep-0590/

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40141

   (12) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (13) https://peps.python.org/pep-0489/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (15) https://peps.python.org/pep-0489/

   (16) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (17) https://peps.python.org/pep-0489/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=40077

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40067

   (20) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (21) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (22) https://bugs.python.org/issue?@action=redirect&bpo=20526

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (24) https://peps.python.org/pep-0489/

   (25) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (26) https://peps.python.org/pep-0489/

   (27) https://bugs.python.org/issue?@action=redirect&bpo=40020

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39939

   (29) https://peps.python.org/pep-0616/

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39481

   (31) https://bugs.python.org/issue?@action=redirect&bpo=32894

   (32) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (33) https://peps.python.org/pep-0590/


File: python.info,  Node: Library<128>,  Next: Documentation<44>,  Prev: Core and Builtins<126>,  Up: Python 3 9 0 alpha 6

1.23.53.3 Library
.................

   - bpo-40398(1): *note typing.get_args(): 2ed. now always returns an
     empty tuple for special generic aliases.

   - bpo-40396(2): Functions *note typing.get_origin(): 2ec, *note
     typing.get_args(): 2ed. and *note typing.get_type_hints(): 6b4.
     support now generic aliases like ‘list[int]’.

   - bpo-38061(3): Optimize the *note subprocess: d6. module on FreeBSD
     using ‘closefrom()’.  A single ‘close(fd)’ syscall is cheap, but
     when ‘sysconf(_SC_OPEN_MAX)’ is high, the loop calling ‘close(fd)’
     on each file descriptor can take several milliseconds.

     The workaround on FreeBSD to improve performance was to load and
     mount the fdescfs kernel module, but this is not enabled by
     default.

     Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans
     (kevans) and Kubilay Kocak (koobs):
     ‘https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274’

   - bpo-38061(4): On FreeBSD, ‘os.closerange(fd_low, fd_high)’ now
     calls ‘closefrom(fd_low)’ if 'fd_high' is greater than or equal to
     ‘sysconf(_SC_OPEN_MAX)’.

     Initial patch by Ed Maste (emaste), Conrad Meyer (cem), Kyle Evans
     (kevans) and Kubilay Kocak (koobs):
     ‘https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242274’

   - bpo-40360(5): The ‘lib2to3’ module is pending deprecation due to
     PEP 617(6).

   - bpo-40138(7): Fix the Windows implementation of *note os.waitpid():
     dc8. for exit code larger than ‘INT_MAX >> 8’.  The exit status is
     now interpreted as an unsigned number.

   - bpo-39942(8): Set “__main__” as the default module name when
     “__name__” is missing in *note typing.TypeVar: 15d.  Patch by
     Weipeng Hong.

   - bpo-40275(9): The *note logging: 87. package is now imported lazily
     in *note unittest: 106. only when the *note assertLogs(): 85f.
     assertion is used.

   - bpo-40275(10): The *note asyncio: a. package is now imported lazily
     in *note unittest: 106. only when the *note
     IsolatedAsyncioTestCase: 30c. class is used.

   - bpo-40330(11): In ‘ShareableList.__setitem__()’, check the size of
     a new string item after encoding it to utf-8, not before.

   - bpo-40148(12): Added ‘pathlib.Path.with_stem()’ to create a new
     Path with the stem replaced.

   - bpo-40325(13): Deprecated support for set objects in
     random.sample().

   - bpo-40257(14): Improved help for the *note typing: 104. module.
     Docstrings are now shown for all special forms and special generic
     aliases (like ‘Union’ and ‘List’).  Using ‘help()’ with generic
     alias like ‘List[int]’ will show the help for the correspondent
     concrete type (‘list’ in this case).

   - bpo-40257(15): *note inspect.getdoc(): a05. no longer returns
     docstring inherited from the type of the object or from parent
     class if it is a class if it is not defined in the object itself.
     In *note pydoc: b5. the documentation string is now shown not only
     for class, function, method etc, but for any object that has its
     own ‘__doc__’ attribute.

   - bpo-40287(16): Fixed ‘SpooledTemporaryFile.seek()’ to return the
     position.

   - bpo-40290(17): Added zscore() to statistics.NormalDist().

   - bpo-40282(18): Allow ‘random.getrandbits(0)’ to succeed and to
     return 0.

   - bpo-40286(19): Add *note random.randbytes(): 1648. function and
     *note random.Random.randbytes(): 933. method to generate random
     bytes.

   - bpo-40277(20): *note collections.namedtuple(): 1ca. now provides a
     human-readable repr for its field accessors.

   - bpo-40270(21): The included copy of sqlite3 on Windows is now
     compiled with the json extension.  This allows the use of functions
     such as ‘json_object’.

   - bpo-29255(22): Wait in ‘KqueueSelector.select’ when no fds are
     registered

   - bpo-40260(23): Ensure *note modulefinder: 91. uses *note
     io.open_code(): 15a7. and respects coding comments.

   - bpo-40234(24): Allow again to spawn daemon threads in
     subinterpreters (revert change which denied them).

   - bpo-39207(25): Workers in *note ProcessPoolExecutor: 8f7. are now
     spawned on demand, only when there are no available idle workers to
     reuse.  This optimizes startup overhead and reduces the amount of
     lost CPU time to idle workers.  Patch by Kyle Stanley.

   - bpo-40091(26): Fix a hang at fork in the logging module: the new
     private _at_fork_reinit() method is now used to reinitialize locks
     at fork in the child process.

   - bpo-40149(27): Implement traverse and clear slots in _abc._abc_data
     type.

   - bpo-40208(28): Remove deprecated ‘symtable.SymbolTable.has_exec()’.

   - bpo-40196(29): Fix a bug in the *note symtable: d8. module that was
     causing incorrectly report global variables as local.  Patch by
     Pablo Galindo.

   - bpo-40190(30): Add support for ‘_SC_AIX_REALMEM’ to
     ‘posix.sysconf()’.

   - bpo-40182(31): Removed the ‘_field_types’ attribute of the *note
     typing.NamedTuple: 2b0. class.

   - bpo-36517(32): Multiple inheritance with *note typing.NamedTuple:
     2b0. now raises an error instead of silently ignoring other types.

   - bpo-40126(33): Fixed reverting multiple patches in unittest.mock.
     Patcher’s ‘__exit__()’ is now never called if its ‘__enter__()’ is
     failed.  Returning true from ‘__exit__()’ silences now the
     exception.

   - bpo-40094(34): CGIHTTPRequestHandler of http.server now logs the
     CGI script exit code, rather than the CGI script exit status of
     os.waitpid().  For example, if the script is killed by signal 11,
     it now logs: “CGI script exit code -11.”

   - bpo-40108(35): Improve the error message when triying to import a
     module using *note runpy: be. and incorrectly using the “.py”
     extension at the end of the module name.  Patch by Pablo Galindo.

   - bpo-40094(36): Add *note os.waitstatus_to_exitcode(): 926.
     function: convert a wait status to an exit code.

   - bpo-40089(37): Fix threading._after_fork(): if fork was not called
     by a thread spawned by threading.Thread, threading._after_fork()
     now creates a _MainThread instance for _main_thread, instead of a
     _DummyThread instance.

   - bpo-40089(38): Add a private ‘_at_fork_reinit()’ method to
     ‘_thread.Lock’, ‘_thread.RLock’, *note threading.RLock: 2de. and
     *note threading.Condition: 1199. classes: reinitialize the lock at
     fork in the child process, reset the lock to the unlocked state.
     Rename also the private ‘_reset_internal_locks()’ method of *note
     threading.Event: 119c. to ‘_at_fork_reinit()’.

   - bpo-25780(39): Expose *note CAN_RAW_JOIN_FILTERS: 93b. in the *note
     socket: cc. module.

   - bpo-39503(40): *note AbstractBasicAuthHandler: 1a16. of *note
     urllib.request: 10b. now parses all WWW-Authenticate HTTP headers
     and accepts multiple challenges per header: use the realm of the
     first Basic challenge.

   - bpo-39812(41): Removed daemon threads from *note
     concurrent.futures: 21. by adding an internal
     ‘threading._register_atexit()’, which calls registered functions
     prior to joining all non-daemon threads.  This allows for
     compatibility with subinterpreters, which don’t support daemon
     threads.

   - bpo-40050(42): Fix ‘importlib._bootstrap_external’: avoid creating
     a new ‘winreg’ builtin module if it’s already available in *note
     sys.modules: 1655, and remove redundant imports.

   - bpo-40014(43): Fix ‘os.getgrouplist()’: if ‘getgrouplist()’
     function fails because the group list is too small, retry with a
     larger group list.  On failure, the glibc implementation of
     ‘getgrouplist()’ sets ‘ngroups’ to the total number of groups.  For
     other implementations, double the group list size.

   - bpo-40017(44): Add *note time.CLOCK_TAI: 1afe. constant if the
     operating system support it.

   - bpo-40016(45): In re docstring, clarify the relationship between
     inline and argument compile flags.

   - bpo-39953(46): Update internal table of OpenSSL error codes in the
     ‘ssl’ module.

   - bpo-36144(47): Added PEP 584(48) operators to *note
     weakref.WeakValueDictionary: 1aff.

   - bpo-36144(49): Added PEP 584(50) operators to *note
     weakref.WeakKeyDictionary: 1b00.

   - bpo-38891(51): Fix linear runtime behaviour of the ‘__getitem__’
     and ‘__setitem__’ methods in *note
     multiprocessing.shared_memory.ShareableList: 1b01.  This avoids
     quadratic performance when iterating a ‘ShareableList’.  Patch by
     Thomas Krennwallner.

   - bpo-39682(52): Remove undocumented support for 'closing' a
     ‘pathlib.Path’ object via its context manager.  The context manager
     magic methods remain, but they are now a no-op, making ‘Path’
     objects immutable.

   - bpo-36144(53): Added PEP 584(54) operators (‘|’ and ‘|=’) to *note
     collections.ChainMap: c3c.

   - bpo-39011(55): Normalization of line endings in ElementTree
     attributes was removed, as line endings which were replaced by
     entity numbers should be preserved in original form.

   - bpo-38410(56): Properly handle *note sys.audit(): 16be. failures in
     *note sys.set_asyncgen_hooks(): 1730.

   - bpo-36541(57): lib2to3 now recognizes named assignment expressions
     (the walrus operator, ‘:=’)

   - bpo-35967(58): In platform, delay the invocation of ‘uname -p’
     until the processor attribute is requested.

   - bpo-35113(59): *note inspect.getsource(): 1619. now returns correct
     source code for inner class with same name as module level class.
     Decorators are also returned as part of source of the class.  Patch
     by Karthikeyan Singaravelan.

   - bpo-33262(60): Deprecate passing None as an argument for *note
     shlex.split(): 53f.’s ‘s’ parameter.  Patch by Zackery Spytz.

   - bpo-31758(61): Prevent crashes when using an uninitialized
     ‘_elementtree.XMLParser’ object.  Patch by Oren Milman.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40398

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40396

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38061

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38061

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40360

   (6) https://peps.python.org/pep-0617/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40138

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39942

   (9) https://bugs.python.org/issue?@action=redirect&bpo=40275

   (10) https://bugs.python.org/issue?@action=redirect&bpo=40275

   (11) https://bugs.python.org/issue?@action=redirect&bpo=40330

   (12) https://bugs.python.org/issue?@action=redirect&bpo=40148

   (13) https://bugs.python.org/issue?@action=redirect&bpo=40325

   (14) https://bugs.python.org/issue?@action=redirect&bpo=40257

   (15) https://bugs.python.org/issue?@action=redirect&bpo=40257

   (16) https://bugs.python.org/issue?@action=redirect&bpo=40287

   (17) https://bugs.python.org/issue?@action=redirect&bpo=40290

   (18) https://bugs.python.org/issue?@action=redirect&bpo=40282

   (19) https://bugs.python.org/issue?@action=redirect&bpo=40286

   (20) https://bugs.python.org/issue?@action=redirect&bpo=40277

   (21) https://bugs.python.org/issue?@action=redirect&bpo=40270

   (22) https://bugs.python.org/issue?@action=redirect&bpo=29255

   (23) https://bugs.python.org/issue?@action=redirect&bpo=40260

   (24) https://bugs.python.org/issue?@action=redirect&bpo=40234

   (25) https://bugs.python.org/issue?@action=redirect&bpo=39207

   (26) https://bugs.python.org/issue?@action=redirect&bpo=40091

   (27) https://bugs.python.org/issue?@action=redirect&bpo=40149

   (28) https://bugs.python.org/issue?@action=redirect&bpo=40208

   (29) https://bugs.python.org/issue?@action=redirect&bpo=40196

   (30) https://bugs.python.org/issue?@action=redirect&bpo=40190

   (31) https://bugs.python.org/issue?@action=redirect&bpo=40182

   (32) https://bugs.python.org/issue?@action=redirect&bpo=36517

   (33) https://bugs.python.org/issue?@action=redirect&bpo=40126

   (34) https://bugs.python.org/issue?@action=redirect&bpo=40094

   (35) https://bugs.python.org/issue?@action=redirect&bpo=40108

   (36) https://bugs.python.org/issue?@action=redirect&bpo=40094

   (37) https://bugs.python.org/issue?@action=redirect&bpo=40089

   (38) https://bugs.python.org/issue?@action=redirect&bpo=40089

   (39) https://bugs.python.org/issue?@action=redirect&bpo=25780

   (40) https://bugs.python.org/issue?@action=redirect&bpo=39503

   (41) https://bugs.python.org/issue?@action=redirect&bpo=39812

   (42) https://bugs.python.org/issue?@action=redirect&bpo=40050

   (43) https://bugs.python.org/issue?@action=redirect&bpo=40014

   (44) https://bugs.python.org/issue?@action=redirect&bpo=40017

   (45) https://bugs.python.org/issue?@action=redirect&bpo=40016

   (46) https://bugs.python.org/issue?@action=redirect&bpo=39953

   (47) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (48) https://peps.python.org/pep-0584/

   (49) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (50) https://peps.python.org/pep-0584/

   (51) https://bugs.python.org/issue?@action=redirect&bpo=38891

   (52) https://bugs.python.org/issue?@action=redirect&bpo=39682

   (53) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (54) https://peps.python.org/pep-0584/

   (55) https://bugs.python.org/issue?@action=redirect&bpo=39011

   (56) https://bugs.python.org/issue?@action=redirect&bpo=38410

   (57) https://bugs.python.org/issue?@action=redirect&bpo=36541

   (58) https://bugs.python.org/issue?@action=redirect&bpo=35967

   (59) https://bugs.python.org/issue?@action=redirect&bpo=35113

   (60) https://bugs.python.org/issue?@action=redirect&bpo=33262

   (61) https://bugs.python.org/issue?@action=redirect&bpo=31758


File: python.info,  Node: Documentation<44>,  Next: Tests<47>,  Prev: Library<128>,  Up: Python 3 9 0 alpha 6

1.23.53.4 Documentation
.......................

   - bpo-27635(1): The pickle documentation incorrectly claimed that
     ‘__new__’ isn’t called by default when unpickling.

   - bpo-39879(2): Updated *note Data model: 1b03. docs to include *note
     dict(): 256. insertion order preservation.  Patch by Furkan Onder
     and Samy Lahfa.

   - bpo-38387(3): Document *note PyDoc_STRVAR: 1b04. macro in the C-API
     reference.

   - bpo-13743(4): Some methods within xml.dom.minidom.Element class are
     now better documented.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27635

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39879

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38387

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13743


File: python.info,  Node: Tests<47>,  Next: Build<51>,  Prev: Documentation<44>,  Up: Python 3 9 0 alpha 6

1.23.53.5 Tests
...............

   - bpo-31904(1): Set expected default encoding in
     test_c_locale_coercion.py for VxWorks RTOS.

   - bpo-40162(2): Update Travis CI configuration to OpenSSL 1.1.1f.

   - bpo-40146(3): Update OpenSSL to 1.1.1f in Azure Pipelines.

   - bpo-40094(4): Add *note test.support.wait_process(): 1b06.
     function.

   - bpo-40003(5): ‘test.bisect_cmd’ now copies Python command line
     options like ‘-O’ or ‘-W’.  Moreover, emit a warning if
     ‘test.bisect_cmd’ is used with ‘-w’/‘--verbose2’ option.

   - bpo-39380(6): Add the encoding in *note ftplib.FTP: 903. and *note
     ftplib.FTP_TLS: 904. to the constructor as keyword-only and change
     the default from ‘latin-1’ to ‘utf-8’ to follow RFC 2640(7).

   - bpo-39793(8): Use the same domain when testing ‘make_msgid’.  Patch
     by Batuhan Taskaya.

   - bpo-1812(9): Fix newline handling in doctest.testfile when loading
     from a package whose loader has a get_data method.  Patch by Peter
     Donis.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40162

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40146

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40094

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40003

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39380

   (7) https://datatracker.ietf.org/doc/html/rfc2640.html

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39793

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1812


File: python.info,  Node: Build<51>,  Next: Windows<44>,  Prev: Tests<47>,  Up: Python 3 9 0 alpha 6

1.23.53.6 Build
...............

   - bpo-38360(1): Support single-argument form of macOS -isysroot flag.

   - bpo-40158(2): Fix CPython MSBuild Properties in NuGet Package
     (build/native/python.props)

   - bpo-38527(3): Fix configure check on Solaris for “float word
     ordering”: sometimes, the correct “grep” command was not being
     used.  Patch by Arnon Yaari.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38360

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40158

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38527


File: python.info,  Node: Windows<44>,  Next: macOS<36>,  Prev: Build<51>,  Up: Python 3 9 0 alpha 6

1.23.53.7 Windows
.................

   - bpo-40164(1): Updates Windows to OpenSSL 1.1.1f

   - bpo-8901(2): Ignore the Windows registry when the ‘-E’ option is
     used.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40164

   (2) https://bugs.python.org/issue?@action=redirect&bpo=8901


File: python.info,  Node: macOS<36>,  Next: IDLE<31>,  Prev: Windows<44>,  Up: Python 3 9 0 alpha 6

1.23.53.8 macOS
...............

   - bpo-38329(1): python.org macOS installers now update the Current
     version symlink of /Library/Frameworks/Python.framework/Versions
     for 3.9 installs.  Previously, Current was only updated for Python
     2.x installs.  This should make it easier to embed Python 3 into
     other macOS applications.

   - bpo-40164(2): Update macOS installer builds to use OpenSSL 1.1.1g.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38329

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40164


File: python.info,  Node: IDLE<31>,  Next: Tools/Demos<24>,  Prev: macOS<36>,  Up: Python 3 9 0 alpha 6

1.23.53.9 IDLE
..............

   - bpo-38439(1): Add a 256×256 pixel IDLE icon to support more modern
     environments.  Created by Andrew Clover.  Delete the unused macOS
     idle.icns icon file.

   - bpo-38689(2): IDLE will no longer freeze when inspect.signature
     fails when fetching a calltip.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38439

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38689


File: python.info,  Node: Tools/Demos<24>,  Next: C API<46>,  Prev: IDLE<31>,  Up: Python 3 9 0 alpha 6

1.23.53.10 Tools/Demos
......................

   - bpo-40385(1): Removed the checkpyc.py tool.  Please see compileall
     without force mode as a potential alternative.

   - bpo-40179(2): Fixed translation of ‘#elif’ in Argument Clinic.

   - bpo-40094(3): Fix ‘which.py’ script exit code: it now uses *note
     os.waitstatus_to_exitcode(): 926. to convert *note os.system():
     14ac. exit status into an exit code.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40385

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40179

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40094


File: python.info,  Node: C API<46>,  Prev: Tools/Demos<24>,  Up: Python 3 9 0 alpha 6

1.23.53.11 C API
................

   - bpo-40241(1): Move the ‘PyGC_Head’ structure to the internal C API.

   - bpo-40170(2): Convert *note PyObject_IS_GC(): 98e. macro to a
     function to hide implementation details.

   - bpo-40241(3): Add the functions *note PyObject_GC_IsTracked(): 980.
     and *note PyObject_GC_IsFinalized(): 981. to the public API to
     allow to query if Python objects are being currently tracked or
     have been already finalized by the garbage collector respectively.
     Patch by Pablo Galindo.

   - bpo-40170(4): The ‘PyObject_NEW()’ macro becomes an alias to the
     *note PyObject_New(): 98f. macro, and the ‘PyObject_NEW_VAR()’
     macro becomes an alias to the *note PyObject_NewVar(): 990. macro,
     to hide implementation details.  They no longer access directly the
     *note PyTypeObject.tp_basicsize: 991. member.

   - bpo-40170(5): *note PyType_HasFeature(): 1ae3. now always calls
     *note PyType_GetFlags(): 1ae4. to hide implementation details.
     Previously, it accessed directly the *note PyTypeObject.tp_flags:
     1a18. member when the limited C API was not used.

   - bpo-40170(6): Convert the ‘PyObject_GET_WEAKREFS_LISTPTR()’ macro
     to a function to hide implementation details: the macro accessed
     directly to the *note PyTypeObject.tp_weaklistoffset: 992. member.

   - bpo-40170(7): Convert *note PyObject_CheckBuffer(): 39b. macro to a
     function to hide implementation details: the macro accessed
     directly the *note PyTypeObject.tp_as_buffer: 993. member.

   - bpo-40170(8): Always declare *note PyIndex_Check(): 994. as an
     opaque function to hide implementation details: remove
     ‘PyIndex_Check()’ macro.  The macro accessed directly the *note
     PyTypeObject.tp_as_number: 995. member.

   - bpo-39947(9): Add *note PyThreadState_GetID(): 97c. function: get
     the unique identifier of a Python thread state.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40241

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (3) https://bugs.python.org/issue?@action=redirect&bpo=40241

   (4) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (5) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (7) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (8) https://bugs.python.org/issue?@action=redirect&bpo=40170

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39947


File: python.info,  Node: Python 3 9 0 alpha 5,  Next: Python 3 9 0 alpha 4,  Prev: Python 3 9 0 alpha 6,  Up: Changelog

1.23.54 Python 3.9.0 alpha 5
----------------------------

'Release date: 2020-03-23'

* Menu:

* Security: Security<36>.
* Core and Builtins: Core and Builtins<127>.
* Library: Library<129>.
* Documentation: Documentation<45>.
* Tests: Tests<48>.
* Build: Build<52>.
* Windows: Windows<45>.
* macOS: macOS<37>.
* IDLE: IDLE<32>.
* Tools/Demos: Tools/Demos<25>.
* C API: C API<47>.


File: python.info,  Node: Security<36>,  Next: Core and Builtins<127>,  Up: Python 3 9 0 alpha 5

1.23.54.1 Security
..................

   - bpo-38576(1): Disallow control characters in hostnames in
     http.client, addressing CVE 2019-18348(2).  Such potentially
     malicious header injection URLs now cause a InvalidURL to be
     raised.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38576

   (2) https://www.cve.org/CVERecord?id=CVE-2019-18348


File: python.info,  Node: Core and Builtins<127>,  Next: Library<129>,  Prev: Security<36>,  Up: Python 3 9 0 alpha 5

1.23.54.2 Core and Builtins
...........................

   - bpo-40010(1): Optimize pending calls in multithreaded applications.
     If a thread different than the main thread schedules a pending call
     (*note Py_AddPendingCall(): 98b.), the bytecode evaluation loop is
     no longer interrupted at each bytecode instruction to check for
     pending calls which cannot be executed.  Only the main thread can
     execute pending calls.

     Previously, the bytecode evaluation loop was interrupted at each
     instruction until the main thread executes pending calls.

   - bpo-1635741(2): Port _weakref extension module to multiphase
     initialization ( PEP 489(3)).

   - bpo-1635741(4): Port _collections module to multiphase
     initialization ( PEP 489(5)).

   - bpo-40010(6): Optimize signal handling in multithreaded
     applications.  If a thread different than the main thread gets a
     signal, the bytecode evaluation loop is no longer interrupted at
     each bytecode instruction to check for pending signals which cannot
     be handled.  Only the main thread of the main interpreter can
     handle signals.

     Previously, the bytecode evaluation loop was interrupted at each
     instruction until the main thread handles signals.

   - bpo-39984(7): If *note Py_AddPendingCall(): 98b. is called in a
     subinterpreter, the function is now scheduled to be called from the
     subinterpreter, rather than being called from the main interpreter.
     Each subinterpreter now has its own list of scheduled calls.

   - bpo-1635741(8): Port _heapq module to multiphase initialization.

   - bpo-1635741(9): Port itertools module to multiphase initialization
     ( PEP 489(10)).

   - bpo-37207(11): Speed up calls to ‘frozenset()’ by using the PEP
     590(12) ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-39984(13): subinterpreters: Move
     ‘_PyRuntimeState.ceval.tracing_possible’ to
     ‘PyInterpreterState.ceval.tracing_possible’: each interpreter now
     has its own variable.

   - bpo-37207(14): Speed up calls to ‘set()’ by using the PEP 590(15)
     ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-1635741(16): Port _statistics module to multiphase
     initialization ( PEP 489(17)).

   - bpo-39968(18): Use inline function to replace extension modules’
     get_module_state macros.

   - bpo-39965(19): Correctly raise ‘SyntaxError’ if 'await' is used
     inside non-async functions and ‘PyCF_ALLOW_TOP_LEVEL_AWAIT’ is set
     (like in the asyncio REPL). Patch by Pablo Galindo.

   - bpo-39562(20): Allow executing asynchronous comprehensions on the
     top level when the ‘PyCF_ALLOW_TOP_LEVEL_AWAIT’ flag is given.
     Patch by Batuhan Taskaya.

   - bpo-37207(21): Speed up calls to ‘tuple()’ by using the PEP 590(22)
     ‘vectorcall’ calling convention.  Patch by Donghee Na.

   - bpo-38373(23): Changed list overallocation strategy.  It no longer
     overallocates if the new size is closer to overallocated size than
     to the old size and adds padding.

   - bpo-39926(24): Update Unicode database to Unicode version 13.0.0.

   - bpo-19466(25): Clear the frames of daemon threads earlier during
     the Python shutdown to call objects destructors.  So “unclosed
     file” resource warnings are now emitted for daemon threads in a
     more reliable way.

   - bpo-38894(26): Fix a bug that was causing incomplete results when
     calling ‘pathlib.Path.glob’ in the presence of symlinks that point
     to files where the user does not have read access.  Patch by Pablo
     Galindo and Matt Wozniski.

   - bpo-39877(27): Fix *note PyEval_RestoreThread(): 3ac. random crash
     at exit with daemon threads.  It now accesses the ‘_PyRuntime’
     variable directly instead of using ‘tstate->interp->runtime’, since
     ‘tstate’ can be a dangling pointer after *note Py_Finalize(): 13a6.
     has been called.  Moreover, the daemon thread now exits before
     trying to take the GIL.

   - bpo-39871(28): Fix a possible *note SystemError: 578. in
     ‘math.{atan2,copysign,remainder}()’ when the first argument cannot
     be converted to a *note float: 2f7.  Patch by Zackery Spytz.

   - bpo-39776(29): Fix race condition where threads created by
     PyGILState_Ensure() could get a duplicate id.

     This affects consumers of tstate->id like the contextvar caching
     machinery, which could return invalid cached objects under heavy
     thread load (observed in embedded scenarios).

   - bpo-39778(30): Fixed a crash due to incorrect handling of weak
     references in ‘collections.OrderedDict’ classes.  Patch by Pablo
     Galindo.

   - bpo-1635741(31): Port audioop extension module to multiphase
     initialization ( PEP 489(32)).

   - bpo-39702(33): Relax *note decorator: 734. grammar restrictions to
     allow any valid expression ( PEP 614(34)).

   - bpo-38091(35): Tweak import deadlock detection code to not deadlock
     itself.

   - bpo-1635741(36): Port _locale extension module to multiphase
     initialization ( PEP 489(37)).

   - bpo-39087(38): Optimize *note PyUnicode_AsUTF8(): bda. and *note
     PyUnicode_AsUTF8AndSize(): 8a0. slightly when they need to create
     internal UTF-8 cache.

   - bpo-39520(39): Fix unparsing of ext slices with no items
     (‘foo[:,]’).  Patch by Batuhan Taskaya.

   - bpo-39220(40): Do not optimize annotations if ‘from __future__
     import annotations’ is used.  Patch by Pablo Galindo.

   - bpo-35712(41): Using *note NotImplemented: 7d6. in a boolean
     context has been deprecated.  Patch contributed by Josh Rosenberg.

   - bpo-22490(42): Don’t leak environment variable
     ‘__PYVENV_LAUNCHER__’ into the interpreter session on macOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40010

   (2) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (3) https://peps.python.org/pep-0489/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (5) https://peps.python.org/pep-0489/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=40010

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39984

   (8) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (10) https://peps.python.org/pep-0489/

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (12) https://peps.python.org/pep-0590/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39984

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (15) https://peps.python.org/pep-0590/

   (16) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (17) https://peps.python.org/pep-0489/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=39968

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39965

   (20) https://bugs.python.org/issue?@action=redirect&bpo=39562

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (22) https://peps.python.org/pep-0590/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=38373

   (24) https://bugs.python.org/issue?@action=redirect&bpo=39926

   (25) https://bugs.python.org/issue?@action=redirect&bpo=19466

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38894

   (27) https://bugs.python.org/issue?@action=redirect&bpo=39877

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39871

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39776

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39778

   (31) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (32) https://peps.python.org/pep-0489/

   (33) https://bugs.python.org/issue?@action=redirect&bpo=39702

   (34) https://peps.python.org/pep-0614/

   (35) https://bugs.python.org/issue?@action=redirect&bpo=38091

   (36) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (37) https://peps.python.org/pep-0489/

   (38) https://bugs.python.org/issue?@action=redirect&bpo=39087

   (39) https://bugs.python.org/issue?@action=redirect&bpo=39520

   (40) https://bugs.python.org/issue?@action=redirect&bpo=39220

   (41) https://bugs.python.org/issue?@action=redirect&bpo=35712

   (42) https://bugs.python.org/issue?@action=redirect&bpo=22490


File: python.info,  Node: Library<129>,  Next: Documentation<45>,  Prev: Core and Builtins<127>,  Up: Python 3 9 0 alpha 5

1.23.54.3 Library
.................

   - bpo-39830(1): Add *note zipfile.Path: 6cc. to ‘__all__’ in the
     *note zipfile: 131. module.

   - bpo-40000(2): Improved error messages for validation of
     ‘ast.Constant’ nodes.  Patch by Batuhan Taskaya.

   - bpo-39999(3): ‘__module__’ of the AST node classes is now set to
     “ast” instead of “_ast”.  Added docstrings for dummy AST node
     classes and deprecated attributes.

   - bpo-39991(4): *note uuid.getnode(): bc5. now skips IPv6 addresses
     with the same string length than a MAC address (17 characters):
     only use MAC addresses.

   - bpo-39988(5): Deprecated ‘ast.AugLoad’ and ‘ast.AugStore’ node
     classes because they are no longer used.

   - bpo-39656(6): Ensure ‘bin/python3.#’ is always present in virtual
     environments on POSIX platforms - by Anthony Sottile.

   - bpo-39969(7): Deprecated ‘ast.Param’ node class because it’s no
     longer used.  Patch by Batuhan Taskaya.

   - bpo-39360(8): Ensure all workers exit when finalizing a
     ‘multiprocessing.Pool’ implicitly via the module finalization
     handlers of multiprocessing.  This fixes a deadlock situation that
     can be experienced when the Pool is not properly finalized via the
     context manager or a call to ‘multiprocessing.Pool.terminate’.
     Patch by Batuhan Taskaya and Pablo Galindo.

   - bpo-35370(9): sys.settrace(), sys.setprofile() and
     _lsprof.Profiler.enable() now properly report *note PySys_Audit():
     372. error if “sys.setprofile” or “sys.settrace” audit event is
     denied.

   - bpo-39936(10): AIX: Fix _aix_support module when the subprocess is
     not available, when building Python from scratch.  It now uses new
     private _bootsubprocess module, rather than having two
     implementations depending if subprocess is available or not.  So
     _aix_support.aix_platform() result is now the same if subprocess is
     available or not.

   - bpo-36144(11): *note collections.OrderedDict: 5de. now implements
     ‘|’ and ‘|=’ ( PEP 584(12)).

   - bpo-39652(13): The column name found in
     ‘sqlite3.Cursor.description’ is now truncated on the first ‘[’ only
     if the PARSE_COLNAMES option is set.

   - bpo-39915(14): Ensure *note
     unittest.mock.AsyncMock.await_args_list: 1b11. has call objects in
     the order of awaited arguments instead of using *note
     unittest.mock.Mock.call_args: 1b12. which has the last value of the
     call.  Patch by Karthikeyan Singaravelan.

   - bpo-36144(15): Updated *note os.environ: 11fe. and *note
     os.environb: 125c. to support PEP 584(16)’s merge (‘|’) and update
     (‘|=’) operators.

   - bpo-38662(17): The ‘ensurepip’ module now invokes ‘pip’ via the
     ‘runpy’ module.  Hence it is no longer tightly coupled with the
     internal API of the bundled ‘pip’ version, allowing easier updates
     to a newer ‘pip’ version both internally and for distributors.

   - bpo-38075(18): Fix the *note random.Random.seed(): 1b13. method
     when a *note bool: 46b. is passed as the seed.

   - bpo-39916(19): More reliable use of ‘os.scandir()’ in
     ‘Path.glob()’.  It no longer emits a ResourceWarning when
     interrupted.

   - bpo-39850(20): *note multiprocessing: 94. now supports abstract
     socket addresses (if abstract sockets are supported in the running
     platform).  When creating arbitrary addresses (like when
     default-constructing *note multiprocessing.connection.Listener:
     17bb. objects) abstract sockets are preferred to avoid the case
     when the temporary-file-generated address is too large for an
     AF_UNIX socket address.  Patch by Pablo Galindo.

   - bpo-36287(21): *note ast.dump(): 8ed. no longer outputs optional
     fields and attributes with default values.  The default values for
     optional fields and attributes of AST nodes are now set as class
     attributes (e.g.  ‘Constant.kind’ is set to ‘None’).

   - bpo-39889(22): Fixed *note ast.unparse(): 8ee. for extended slices
     containing a single element (e.g.  ‘a[i:j,]’).  Remove redundant
     tuples when index with a tuple (e.g.  ‘a[i, j]’).

   - bpo-39828(23): Fix *note json.tool: 83. to catch *note
     BrokenPipeError: 109a.  Patch by Donghee Na.

   - bpo-13487(24): Avoid a possible '“RuntimeError: dictionary changed
     size during iteration”' from *note inspect.getmodule(): 1913. when
     it tried to loop through *note sys.modules: 1655.

   - bpo-39674(25): Revert “bpo-37330(26): open() no longer accept ‘U’
     in file mode”.  The “U” mode of open() is kept in Python 3.9 to
     ease transition from Python 2.7, but will be removed in Python
     3.10.

   - bpo-28577(27): The hosts method on 32-bit prefix length
     IPv4Networks and 128-bit prefix IPv6Networks now returns a list
     containing the single Address instead of an empty list.

   - bpo-39826(28): Add getConnection method to logging HTTPHandler to
     enable custom connections.

   - bpo-39763(29): Reimplement ‘distutils.spawn.spawn’ function with
     the *note subprocess: d6. module.

   - bpo-39794(30): Add –without-decimal-contextvar build option.  This
     enables a thread-local rather than a coroutine local context.

   - bpo-36144(31): *note collections.defaultdict: 1201. now implements
     ‘|’ ( PEP 584(32)).

   - bpo-39517(33): Fix runpy.run_path() when using pathlike objects

   - bpo-39775(34): Change ‘inspect.Signature.parameters’ back to
     ‘collections.OrderedDict’.  This was changed to ‘dict’ in Python
     3.9.0a4.

   - bpo-39678(35): Refactor queue_manager in *note
     concurrent.futures.ProcessPoolExecutor: 8f7. to make it easier to
     maintain.

   - bpo-39764(36): Fix AttributeError when calling get_stack on a
     PyAsyncGenObject Task

   - bpo-39769(37): The *note compileall.compile_dir(): b3e. function’s
     'ddir' parameter and the compileall command line flag ‘-d’ no
     longer write the wrong pathname to the generated pyc file for
     submodules beneath the root of the directory tree being compiled.
     This fixes a regression introduced with Python 3.5.

   - bpo-36144(38): *note types.MappingProxyType: 470. objects now
     support the merge (‘|’) operator from PEP 584(39).

   - bpo-38691(40): The *note importlib: 77. module now ignores the
     *note PYTHONCASEOK: 966. environment variable when the *note -E:
     967. or *note -I: 968. command line options are being used.

   - bpo-39719(41): Remove ‘tempfile.SpooledTemporaryFile.softspace()’
     as files no longer have the ‘softspace’ attribute in Python 3.
     Patch by Shantanu.

   - bpo-39667(42): Improve pathlib.Path compatibility on zipfile.Path
     and correct performance degradation as found in zipp 3.0.

   - bpo-39638(43): Keep ASDL signatures in the docstrings for ‘AST’
     nodes.  Patch by Batuhan Taskaya

   - bpo-39639(44): Deprecated ‘ast.Suite’ node class because it’s no
     longer used.  Patch by Batuhan Taskaya.

   - bpo-39609(45): Add thread_name_prefix to default asyncio executor

   - bpo-39548(46): Fix handling of header in *note
     urllib.request.AbstractDigestAuthHandler: 1b14. when the optional
     ‘qop’ parameter is not present.

   - bpo-39509(47): HTTP status codes ‘103 EARLY_HINTS’ and ‘425
     TOO_EARLY’ are added to *note http.HTTPStatus: 909.  Patch by
     Donghee Na.

   - bpo-39507(48): Adding HTTP status 418 “I’m a Teapot” to HTTPStatus
     in http library.  Patch by Ross Rhodes.

   - bpo-39495(49): Remove default value from 'attrs' parameter of *note
     xml.etree.ElementTree.TreeBuilder.start(): 1b15. for consistency
     between Python and C implementations.

   - bpo-38971(50): Open issue in the BPO indicated a desire to make the
     implementation of codecs.open() at parity with io.open(), which
     implements a try/except to assure file stream gets closed before an
     exception is raised.

   - bpo-38641(51): Added starred expressions support to ‘return’ and
     ‘yield’ statements for ‘lib2to3’.  Patch by Vlad Emelianov.

   - bpo-37534(52): When using minidom module to generate XML documents
     the ability to add Standalone Document Declaration is added.  All
     the changes are made to generate a document in compliance with
     Extensible Markup Language (XML) 1.0 (Fifth Edition) W3C
     Recommendation (available here:
     ‘https://www.w3.org/TR/xml/#sec-prolog-dtd’).

   - bpo-34788(53): Add support for scoped IPv6 addresses to *note
     ipaddress: 80.  Patch by Oleksandr Pavliuk.

   - bpo-34822(54): Simplified AST for subscription.  Simple indices are
     now represented by their value, extended slices are represented as
     tuples.  *note ast: 8. classes ‘Index’ and ‘ExtSlice’ are
     considered deprecated and will be removed in future Python
     versions.  In the meantime, ‘Index(value)’ now returns a ‘value’
     itself, ‘ExtSlice(slices)’ returns ‘Tuple(slices, Load())’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39830

   (2) https://bugs.python.org/issue?@action=redirect&bpo=40000

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39999

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39991

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39988

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39656

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39969

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39360

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35370

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39936

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (12) https://peps.python.org/pep-0584/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39652

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39915

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (16) https://peps.python.org/pep-0584/

   (17) https://bugs.python.org/issue?@action=redirect&bpo=38662

   (18) https://bugs.python.org/issue?@action=redirect&bpo=38075

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39916

   (20) https://bugs.python.org/issue?@action=redirect&bpo=39850

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36287

   (22) https://bugs.python.org/issue?@action=redirect&bpo=39889

   (23) https://bugs.python.org/issue?@action=redirect&bpo=39828

   (24) https://bugs.python.org/issue?@action=redirect&bpo=13487

   (25) https://bugs.python.org/issue?@action=redirect&bpo=39674

   (26) https://bugs.python.org/issue?@action=redirect&bpo=37330

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28577

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39826

   (29) https://bugs.python.org/issue?@action=redirect&bpo=39763

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39794

   (31) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (32) https://peps.python.org/pep-0584/

   (33) https://bugs.python.org/issue?@action=redirect&bpo=39517

   (34) https://bugs.python.org/issue?@action=redirect&bpo=39775

   (35) https://bugs.python.org/issue?@action=redirect&bpo=39678

   (36) https://bugs.python.org/issue?@action=redirect&bpo=39764

   (37) https://bugs.python.org/issue?@action=redirect&bpo=39769

   (38) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (39) https://peps.python.org/pep-0584/

   (40) https://bugs.python.org/issue?@action=redirect&bpo=38691

   (41) https://bugs.python.org/issue?@action=redirect&bpo=39719

   (42) https://bugs.python.org/issue?@action=redirect&bpo=39667

   (43) https://bugs.python.org/issue?@action=redirect&bpo=39638

   (44) https://bugs.python.org/issue?@action=redirect&bpo=39639

   (45) https://bugs.python.org/issue?@action=redirect&bpo=39609

   (46) https://bugs.python.org/issue?@action=redirect&bpo=39548

   (47) https://bugs.python.org/issue?@action=redirect&bpo=39509

   (48) https://bugs.python.org/issue?@action=redirect&bpo=39507

   (49) https://bugs.python.org/issue?@action=redirect&bpo=39495

   (50) https://bugs.python.org/issue?@action=redirect&bpo=38971

   (51) https://bugs.python.org/issue?@action=redirect&bpo=38641

   (52) https://bugs.python.org/issue?@action=redirect&bpo=37534

   (53) https://bugs.python.org/issue?@action=redirect&bpo=34788

   (54) https://bugs.python.org/issue?@action=redirect&bpo=34822


File: python.info,  Node: Documentation<45>,  Next: Tests<48>,  Prev: Library<129>,  Up: Python 3 9 0 alpha 5

1.23.54.4 Documentation
.......................

   - bpo-39868(1): Updated the Language Reference for PEP 572(2).

   - bpo-13790(3): Change ‘string’ to ‘specification’ in format doc.

   - bpo-17422(4): The language reference no longer restricts default
     class namespaces to dicts only.

   - bpo-39530(5): Fix misleading documentation about mixed-type numeric
     comparisons.

   - bpo-39718(6): Update *note token: fa. documentation to reflect
     additions in Python 3.8

   - bpo-39677(7): Changed operand name of 'MAKE_FUNCTION' from 'argc'
     to 'flags' for module *note dis: 38.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39868

   (2) https://peps.python.org/pep-0572/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13790

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17422

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39530

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39718

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39677


File: python.info,  Node: Tests<48>,  Next: Build<52>,  Prev: Documentation<45>,  Up: Python 3 9 0 alpha 5

1.23.54.5 Tests
...............

   - bpo-40019(1): test_gdb now skips tests if it detects that gdb
     failed to read debug information because the Python binary is
     optimized.

   - bpo-27807(2): ‘test_site.test_startup_imports()’ is now skipped if
     a path of *note sys.path: 3b7. contains a ‘.pth’ file.

   - bpo-26067(3): Do not fail test_shutil test_chown test when uid or
     gid of user cannot be resolved to a name.

   - bpo-39855(4): test_subprocess.test_user() now skips the test on an
     user name if the user name doesn’t exist.  For example, skip the
     test if the user “nobody” doesn’t exist on Linux.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40019

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27807

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26067

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39855


File: python.info,  Node: Build<52>,  Next: Windows<45>,  Prev: Tests<48>,  Up: Python 3 9 0 alpha 5

1.23.54.6 Build
...............

   - bpo-39761(1): Fix build with DTrace but without additional DFLAGS.

   - bpo-39763(2): setup.py now uses a basic implementation of the *note
     subprocess: d6. module if the ‘subprocess’ module is not available:
     before required C extension modules are built.

   - bpo-1294959(3): Add ‘--with-platlibdir’ option to the configure
     script: name of the platform-specific library directory, stored in
     the new *note sys.platlibdir: 942. attribute.  It is used to build
     the path of platform-specific extension modules and the path of the
     standard library.  It is equal to ‘"lib"’ on most platforms.  On
     Fedora and SuSE, it is equal to ‘"lib64"’ on 64-bit platforms.
     Patch by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor
     Stinner.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39761

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39763

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1294959


File: python.info,  Node: Windows<45>,  Next: macOS<37>,  Prev: Build<52>,  Up: Python 3 9 0 alpha 5

1.23.54.7 Windows
.................

   - bpo-39930(1): Ensures the required ‘vcruntime140.dll’ is included
     in install packages.

   - bpo-39847(2): Avoid hang when computer is hibernated whilst waiting
     for a mutex (for lock-related objects from *note threading: ed.)
     around 49-day uptime.

   - bpo-38597(3): ‘distutils’ will no longer statically link
     ‘vcruntime140.dll’ when a redistributable version is unavailable.
     All future releases of CPython will include a copy of this DLL to
     ensure distributed extensions can continue to load.

   - bpo-38380(4): Update Windows builds to use SQLite 3.31.1

   - bpo-39789(5): Update Windows release build machines to Visual
     Studio 2019 (MSVC 14.2).

   - bpo-34803(6): Package for nuget.org now includes repository
     reference and bundled icon image.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39930

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39847

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38597

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38380

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39789

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34803


File: python.info,  Node: macOS<37>,  Next: IDLE<32>,  Prev: Windows<45>,  Up: Python 3 9 0 alpha 5

1.23.54.8 macOS
...............

   - bpo-38380(1): Update macOS builds to use SQLite 3.31.1

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38380


File: python.info,  Node: IDLE<32>,  Next: Tools/Demos<25>,  Prev: macOS<37>,  Up: Python 3 9 0 alpha 5

1.23.54.9 IDLE
..............

   - bpo-27115(1): For ‘Go to Line’, use a Query box subclass with IDLE
     standard behavior and improved error checking.

   - bpo-39885(2): Since clicking to get an IDLE context menu moves the
     cursor, any text selection should be and now is cleared.

   - bpo-39852(3): Edit “Go to line” now clears any selection,
     preventing accidental deletion.  It also updates Ln and Col on the
     status bar.

   - bpo-39781(4): Selecting code context lines no longer causes a jump.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27115

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39885

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39852

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39781


File: python.info,  Node: Tools/Demos<25>,  Next: C API<47>,  Prev: IDLE<32>,  Up: Python 3 9 0 alpha 5

1.23.54.10 Tools/Demos
......................

   - bpo-36184(1): Port python-gdb.py to FreeBSD. python-gdb.py now
     checks for “take_gil” function name to check if a frame tries to
     acquire the GIL, instead of checking for “pthread_cond_timedwait”
     which is specific to Linux and can be a different condition than
     the GIL.

   - bpo-38080(2): Added support to fix ‘getproxies’ in the
     ‘lib2to3.fixes.fix_urllib’ module.  Patch by José Roberto Meza
     Cabrera.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36184

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38080


File: python.info,  Node: C API<47>,  Prev: Tools/Demos<25>,  Up: Python 3 9 0 alpha 5

1.23.54.11 C API
................

   - bpo-40024(1): Add *note PyModule_AddType(): 97f. helper function:
     add a type to a module.  Patch by Donghee Na.

   - bpo-39946(2): Remove ‘_PyRuntime.getframe’ hook and remove
     ‘_PyThreadState_GetFrame’ macro which was an alias to
     ‘_PyRuntime.getframe’.  They were only exposed by the internal C
     API. Remove also ‘PyThreadFrameGetter’ type.

   - bpo-39947(3): Add *note PyThreadState_GetFrame(): 791. function:
     get the current frame of a Python thread state.

   - bpo-37207(4): Add _PyArg_NoKwnames helper function.  Patch by
     Donghee Na.

   - bpo-39947(5): Add *note PyThreadState_GetInterpreter(): 97b.: get
     the interpreter of a Python thread state.

   - bpo-39947(6): Add *note PyInterpreterState_Get(): 3b0. function to
     the limited C API.

   - bpo-35370(7): If *note PySys_Audit(): 372. fails in *note
     PyEval_SetProfile(): 154c. or *note PyEval_SetTrace(): 424, log the
     error as an unraisable exception.

   - bpo-39947(8): Move the static inline function flavor of
     Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() to the internal
     C API: they access PyThreadState attributes.  The limited C API
     provides regular functions which hide implementation details.

   - bpo-39947(9): Py_TRASHCAN_BEGIN_CONDITION and Py_TRASHCAN_END macro
     no longer access PyThreadState attributes, but call new private
     _PyTrash_begin() and _PyTrash_end() functions which hide
     implementation details.

   - bpo-39884(10): *note PyDescr_NewMethod(): 1b1e. and *note
     PyCFunction_NewEx(): 1b1f. now include the method name in the
     SystemError “bad call flags” error message to ease debug.

   - bpo-39877(11): Deprecated ‘PyEval_InitThreads()’ and
     ‘PyEval_ThreadsInitialized()’.  Calling ‘PyEval_InitThreads()’ now
     does nothing.

   - bpo-38249(12): *note Py_UNREACHABLE: bd3. is now implemented with
     ‘__builtin_unreachable()’ and analogs in release mode.

   - bpo-38643(13): *note PyNumber_ToBase(): 1919. now raises a *note
     SystemError: 578. instead of crashing when called with invalid
     base.

   - bpo-39882(14): The *note Py_FatalError(): 98d. function is replaced
     with a macro which logs automatically the name of the current
     function, unless the ‘Py_LIMITED_API’ macro is defined.

   - bpo-39824(15): Extension modules: *note m_traverse: 984, *note
     m_clear: 985. and *note m_free: 986. functions of *note
     PyModuleDef: 987. are no longer called if the module state was
     requested but is not allocated yet.  This is the case immediately
     after the module is created and before the module is executed
     (*note Py_mod_exec: 988. function).  More precisely, these
     functions are not called if *note m_size: 989. is greater than 0
     and the module state (as returned by *note PyModule_GetState():
     98a.) is ‘NULL’.

     Extension modules without module state (‘m_size <= 0’) are not
     affected.

   - bpo-38913(16): Fixed segfault in ‘Py_BuildValue()’ called with a
     format containing “#” and undefined PY_SSIZE_T_CLEAN whwn an
     exception is set.

   - bpo-38500(17): Add a private API to get and set the frame
     evaluation function: add *note
     _PyInterpreterState_GetEvalFrameFunc(): 1b20. and *note
     _PyInterpreterState_SetEvalFrameFunc(): 1b21. C functions.  The
     *note _PyFrameEvalFunction: 779. function type now takes a 'tstate'
     parameter.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=40024

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39946

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35370

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39947

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39884

   (11) https://bugs.python.org/issue?@action=redirect&bpo=39877

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38249

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38643

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39882

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39824

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38913

   (17) https://bugs.python.org/issue?@action=redirect&bpo=38500


File: python.info,  Node: Python 3 9 0 alpha 4,  Next: Python 3 9 0 alpha 3,  Prev: Python 3 9 0 alpha 5,  Up: Changelog

1.23.55 Python 3.9.0 alpha 4
----------------------------

'Release date: 2020-02-25'

* Menu:

* Security: Security<37>.
* Core and Builtins: Core and Builtins<128>.
* Library: Library<130>.
* Documentation: Documentation<46>.
* Tests: Tests<49>.
* Build: Build<53>.
* Windows: Windows<46>.
* IDLE: IDLE<33>.
* C API: C API<48>.


File: python.info,  Node: Security<37>,  Next: Core and Builtins<128>,  Up: Python 3 9 0 alpha 4

1.23.55.1 Security
..................

   - bpo-39184(1): Add audit events to functions in ‘fcntl’, ‘msvcrt’,
     ‘os’, ‘resource’, ‘shutil’, ‘signal’ and ‘syslog’.

   - bpo-39401(2): Avoid unsafe DLL load at startup on Windows 7 and
     earlier.

   - bpo-39184(3): Add audit events to command execution functions in os
     and pty modules.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39184

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39401

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39184


File: python.info,  Node: Core and Builtins<128>,  Next: Library<130>,  Prev: Security<37>,  Up: Python 3 9 0 alpha 4

1.23.55.2 Core and Builtins
...........................

   - bpo-39382(1): Fix a use-after-free in the single inheritance path
     of ‘issubclass()’, when the ‘__bases__’ of an object has a single
     reference, and so does its first item.  Patch by Yonatan
     Goldschmidt.

   - bpo-39573(2): Update clinic tool to use *note Py_IS_TYPE(): 1946.
     Patch by Donghee Na.

   - bpo-39619(3): Enable use of *note os.chroot(): 1b25. on HP-UX
     systems.

   - bpo-39573(4): Add *note Py_IS_TYPE(): 1946. static inline function
     to check whether the object 'o' type is 'type'.

   - bpo-39606(5): Fix regression caused by fix for bpo-39386(6), that
     prevented calling ‘aclose’ on an async generator that had already
     been closed or exhausted.

   - bpo-39579(7): Change the ending column offset of ‘Attribute’ nodes
     constructed in ‘ast_for_dotted_name’ to point at the end of the
     current node and not at the end of the last ‘NAME’ node.

   - bpo-1635741(8): Port _crypt extension module to multiphase
     initialization ( PEP 489(9)).

   - bpo-1635741(10): Port _contextvars extension module to multiphase
     initialization ( PEP 489(11)).

   - bpo-39510(12): Fix segfault in ‘readinto()’ method on closed
     BufferedReader.

   - bpo-39502(13): Fix *note time.localtime(): 1548. on 64-bit AIX to
     support years before 1902 and after 2038.  Patch by M Felt.

   - bpo-39492(14): Fix a reference cycle in the C Pickler that was
     preventing the garbage collection of deleted, pickled objects.

   - bpo-39453(15): Fixed a possible crash in ‘list.__contains__()’ when
     a list is changed during comparing items.  Patch by Donghee Na.

   - bpo-39434(16): *note floor division: 94e. of float operation now
     has a better performance.  Also the message of *note
     ZeroDivisionError: 94f. for this operation is updated.  Patch by
     Donghee Na.

   - bpo-1635741(17): Port _codecs extension module to multiphase
     initialization ( PEP 489(18)).

   - bpo-1635741(19): Port _bz2 extension module to multiphase
     initialization ( PEP 489(20)).

   - bpo-1635741(21): Port _abc extension module to multiphase
     initialization ( PEP 489(22)).

   - bpo-39320(23): Replace two complex bytecodes for building dicts
     with two simpler ones.  The new bytecodes ‘DICT_MERGE’ and
     ‘DICT_UPDATE’ have been added The old bytecodes ‘BUILD_MAP_UNPACK’
     and ‘BUILD_MAP_UNPACK_WITH_CALL’ have been removed.

   - bpo-39219(24): Syntax errors raised in the tokenizer now always set
     correct “text” and “offset” attributes.

   - bpo-36051(25): Drop the GIL during large ‘bytes.join’ operations.
     Patch by Bruce Merry.

   - bpo-38960(26): Fix DTrace build issues on FreeBSD. Patch by David
     Carlier.

   - bpo-37207(27): Speed up calls to ‘range()’ by about 30%, by using
     the PEP 590 ‘vectorcall’ calling convention.  Patch by Mark
     Shannon.

   - bpo-36144(28): *note dict: 256. (and *note collections.UserDict:
     1b26.) objects now support PEP 584’s merge (‘|’) and update (‘|=’)
     operators.  Patch by Brandt Bucher.

   - bpo-32856(29): Optimized the idiom for assignment a temporary
     variable in comprehensions.  Now ‘for y in [expr]’ in
     comprehensions is as fast as a simple assignment ‘y = expr’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39382

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39619

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39606

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39386

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39579

   (8) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (9) https://peps.python.org/pep-0489/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (11) https://peps.python.org/pep-0489/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39510

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39502

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39492

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39453

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39434

   (17) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (18) https://peps.python.org/pep-0489/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (20) https://peps.python.org/pep-0489/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (22) https://peps.python.org/pep-0489/

   (23) https://bugs.python.org/issue?@action=redirect&bpo=39320

   (24) https://bugs.python.org/issue?@action=redirect&bpo=39219

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36051

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38960

   (27) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (28) https://bugs.python.org/issue?@action=redirect&bpo=36144

   (29) https://bugs.python.org/issue?@action=redirect&bpo=32856


File: python.info,  Node: Library<130>,  Next: Documentation<46>,  Prev: Core and Builtins<128>,  Up: Python 3 9 0 alpha 4

1.23.55.3 Library
.................

   - bpo-30566(1): Fix *note IndexError: 1585. when trying to decode an
     invalid string with punycode codec.

   - bpo-39649(2): Remove obsolete check for ‘__args__’ in
     ‘bdb.Bdb.format_stack_entry’.

   - bpo-39648(3): Expanded *note math.gcd(): 919. and *note math.lcm():
     91a. to handle multiple arguments.

   - bpo-39681(4): Fix a regression where the C pickle module wouldn’t
     allow unpickling from a file-like object that doesn’t expose a
     readinto() method.

   - bpo-35950(5): Raise *note io.UnsupportedOperation: 1b28. in
     ‘io.BufferedReader.truncate()’ when it is called on a read-only
     *note io.BufferedReader: 1253. instance.

   - bpo-39479(6): Add *note math.lcm(): 91a. function: least common
     multiple.

   - bpo-39674(7): Revert “Do not expose abstract collection classes in
     the collections module” change (bpo-25988(8)).  Aliases to ABC like
     collections.Mapping are kept in Python 3.9 to ease transition from
     Python 2.7, but will be removed in Python 3.10.

   - bpo-39104(9): Fix hanging ProcessPoolExcutor on
     ‘shutdown(wait=False)’ when a task has failed pickling.

   - bpo-39627(10): Fixed TypedDict totality check for inherited keys.

   - bpo-39474(11): Fixed starting position of AST for expressions like
     ‘(a)(b)’, ‘(a)[b]’ and ‘(a).b’.

   - bpo-21016(12): The *note pydoc: b5. and *note trace: fd. modules
     now use the *note sysconfig: db. module to get the path to the
     Python standard library, to support uncommon installation path like
     ‘/usr/lib64/python3.9/’ on Fedora.  Patch by Jan Matějek.

   - bpo-39590(13): Collections.deque now holds strong references during
     deque.__contains__ and deque.count, fixing crashes.

   - bpo-39586(14): The distutils ‘bdist_msi’ command is deprecated in
     Python 3.9, use ‘bdist_wheel’ (wheel packages) instead.

   - bpo-39595(15): Improved performance of zipfile.Path for files with
     a large number of entries.  Also improved performance and fixed
     minor issue as published with importlib_metadata 1.5(16).

   - bpo-39350(17): Fix regression in *note fractions.Fraction: 1e7. if
     the numerator and/or the denominator is an *note int: 257.
     subclass.  The *note math.gcd(): 919. function is now used to
     normalize the 'numerator' and 'denominator'.  ‘math.gcd()’ always
     return a ‘int’ type.  Previously, the GCD type depended on
     'numerator' and 'denominator'.

   - bpo-39567(18): Added audit for *note os.walk(): 4ac, *note
     os.fwalk(): b77, *note pathlib.Path.glob(): 22d. and *note
     pathlib.Path.rglob(): 22e.

   - bpo-39559(19): Remove unused, undocumented argument ‘getters’ from
     *note uuid.getnode(): bc5.

   - bpo-38149(20): *note sys.audit(): 16be. is now called only once per
     call of *note glob.glob(): 29f. and *note glob.iglob(): 80d.

   - bpo-39546(21): Fix a regression in *note ArgumentParser: 53c. where
     ‘allow_abbrev=False’ was ignored for long options that used a
     prefix character other than “-“.

   - bpo-39450(22): Striped whitespace from docstring before returning
     it from ‘unittest.case.shortDescription()’.

   - bpo-12915(23): A new function ‘resolve_name’ has been added to the
     ‘pkgutil’ module.  This resolves a string of the form ‘'a.b.c.d'’
     or ‘'a.b:c.d'’ to an object.  In the example, ‘a.b’ is a
     package/module and ‘c.d’ is an object within that package/module
     reached via recursive attribute access.

   - bpo-39353(24): The *note binascii.crc_hqx(): 737. function is no
     longer deprecated.

   - bpo-39493(25): Mark ‘typing.IO.closed’ as a property

   - bpo-39491(26): Add *note typing.Annotated: 947. and
     ‘include_extras’ parameter to *note typing.get_type_hints(): 6b4.
     as part of PEP 593(27).  Patch by Till Varoquaux, documentation by
     Till Varoquaux and Konstantin Kashin.

   - bpo-39485(28): Fix a bug in *note unittest.mock.create_autospec():
     1712. that would complain about the wrong number of arguments for
     custom descriptors defined in an extension module returning
     functions.

   - bpo-38932(29): Mock fully resets child objects on reset_mock().
     Patch by Vegard Stikbakke

   - bpo-39082(30): Allow AsyncMock to correctly patch static/class
     methods

   - bpo-39432(31): Implement PEP-489 algorithm for non-ascii “PyInit_…”
     symbol names in distutils to make it export the correct init symbol
     also on Windows.

   - bpo-18819(32): Omit ‘devmajor’ and ‘devminor’ fields for non-device
     files in *note tarfile: de. archives, enabling bit-for-bit
     compatibility with GNU ‘tar(1)’.

   - bpo-39349(33): Added a new 'cancel_futures' parameter to *note
     concurrent.futures.Executor.shutdown(): 8f6. that cancels all
     pending futures which have not started running, instead of waiting
     for them to complete before shutting down the executor.

   - bpo-39274(34): ‘bool(fraction.Fraction)’ now returns a boolean even
     if (numerator != 0) does not return a boolean (ex: numpy number).

   - bpo-34793(35): Remove support for ‘with (await asyncio.lock):’ and
     ‘with (yield from asyncio.lock):’.  The same is correct for
     ‘asyncio.Condition’ and ‘asyncio.Semaphore’.

   - bpo-25597(36): Ensure, if ‘wraps’ is supplied to *note
     unittest.mock.MagicMock: ec3, it is used to calculate return values
     for the magic methods instead of using the default return values.
     Patch by Karthikeyan Singaravelan.

   - bpo-36350(37): ‘inspect.Signature.parameters’ and
     ‘inspect.BoundArguments.arguments’ are now dicts instead of
     OrderedDicts.  Patch contributed by Rémi Lapeyre.

   - bpo-35727(38): Fix sys.exit() and sys.exit(None) exit code
     propagation when used in multiprocessing.Process.

   - bpo-32173(39): * Add ‘lazycache’ function to ‘__all__’.  * Use
     ‘dict.clear’ to clear the cache.  * Refactoring ‘getline’ function
     and ‘checkcache’ function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30566

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39648

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39681

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35950

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39479

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39674

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25988

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39104

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39627

   (11) https://bugs.python.org/issue?@action=redirect&bpo=39474

   (12) https://bugs.python.org/issue?@action=redirect&bpo=21016

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39590

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39586

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39595

   (16) 
https://importlib-metadata.readthedocs.io/en/latest/history.html#v1-5-0

   (17) https://bugs.python.org/issue?@action=redirect&bpo=39350

   (18) https://bugs.python.org/issue?@action=redirect&bpo=39567

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39559

   (20) https://bugs.python.org/issue?@action=redirect&bpo=38149

   (21) https://bugs.python.org/issue?@action=redirect&bpo=39546

   (22) https://bugs.python.org/issue?@action=redirect&bpo=39450

   (23) https://bugs.python.org/issue?@action=redirect&bpo=12915

   (24) https://bugs.python.org/issue?@action=redirect&bpo=39353

   (25) https://bugs.python.org/issue?@action=redirect&bpo=39493

   (26) https://bugs.python.org/issue?@action=redirect&bpo=39491

   (27) https://peps.python.org/pep-0593/

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39485

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38932

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39082

   (31) https://bugs.python.org/issue?@action=redirect&bpo=39432

   (32) https://bugs.python.org/issue?@action=redirect&bpo=18819

   (33) https://bugs.python.org/issue?@action=redirect&bpo=39349

   (34) https://bugs.python.org/issue?@action=redirect&bpo=39274

   (35) https://bugs.python.org/issue?@action=redirect&bpo=34793

   (36) https://bugs.python.org/issue?@action=redirect&bpo=25597

   (37) https://bugs.python.org/issue?@action=redirect&bpo=36350

   (38) https://bugs.python.org/issue?@action=redirect&bpo=35727

   (39) https://bugs.python.org/issue?@action=redirect&bpo=32173


File: python.info,  Node: Documentation<46>,  Next: Tests<49>,  Prev: Library<130>,  Up: Python 3 9 0 alpha 4

1.23.55.4 Documentation
.......................

   - bpo-17422(1): The language reference now specifies restrictions on
     class namespaces.  Adapted from a patch by Ethan Furman.

   - bpo-39572(2): Updated documentation of ‘total’ flag of ‘TypedDict’.

   - bpo-39654(3): In pyclbr doc, update ‘class’ to ‘module’ where
     appropriate and add readmodule comment.  Patch by Hakan Çelik.

   - bpo-39153(4): Clarify refcounting semantics for the following
     functions: - PyObject_SetItem - PyMapping_SetItemString -
     PyDict_SetItem - PyDict_SetItemString

   - bpo-39392(5): Explain that when filling with turtle, overlap
     regions may be left unfilled.

   - bpo-39369(6): Update mmap readline method description.  The fact
     that the readline method does update the file position should not
     be ignored since this might give the impression for the programmer
     that it doesn’t update it.

   - bpo-9056(7): Include subsection in TOC for PDF version of docs.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17422

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39572

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39654

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39153

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39392

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39369

   (7) https://bugs.python.org/issue?@action=redirect&bpo=9056


File: python.info,  Node: Tests<49>,  Next: Build<53>,  Prev: Documentation<46>,  Up: Python 3 9 0 alpha 4

1.23.55.5 Tests
...............

   - bpo-38325(1): Skip tests on non-BMP characters of
     test_winconsoleio.

   - bpo-39502(2): Skip test_zipfile.test_add_file_after_2107() if *note
     time.localtime(): 1548. fails with *note OverflowError: 888.  It is
     the case on AIX 6.1 for example.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38325

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39502


File: python.info,  Node: Build<53>,  Next: Windows<46>,  Prev: Tests<49>,  Up: Python 3 9 0 alpha 4

1.23.55.6 Build
...............

   - bpo-39489(1): Remove ‘COUNT_ALLOCS’ special build.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39489


File: python.info,  Node: Windows<46>,  Next: IDLE<33>,  Prev: Build<53>,  Up: Python 3 9 0 alpha 4

1.23.55.7 Windows
.................

   - bpo-39553(1): Delete unused code related to SxS manifests.

   - bpo-39439(2): Honor the Python path when a virtualenv is active on
     Windows.

   - bpo-39393(3): Improve the error message when attempting to load a
     DLL with unresolved dependencies.

   - bpo-38883(4): *note home(): e76. and *note expanduser(): e75. on
     Windows now prefer ‘USERPROFILE’ and no longer use ‘HOME’, which is
     not normally set for regular user accounts.  This makes them again
     behave like *note os.path.expanduser(): a21, which was changed to
     ignore ‘HOME’ in 3.8, see bpo-36264(5).

   - bpo-39185(6): The build.bat script has additional options for
     very-quiet output (-q) and very-verbose output (-vv)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39553

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39439

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39393

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38883

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36264

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39185


File: python.info,  Node: IDLE<33>,  Next: C API<48>,  Prev: Windows<46>,  Up: Python 3 9 0 alpha 4

1.23.55.8 IDLE
..............

   - bpo-39663(1): Add tests for pyparse find_good_parse_start().

   - bpo-39600(2): In the font configuration window, remove duplicated
     font names.

   - bpo-30780(3): Add remaining configdialog tests for buttons and
     highlights and keys tabs.

   - bpo-39388(4): IDLE Settings Cancel button now cancels pending
     changes

   - bpo-38792(5): Close an IDLE shell calltip if a *note
     KeyboardInterrupt: 9dc. or shell restart occurs.  Patch by Zackery
     Spytz.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39663

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39600

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30780

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39388

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38792


File: python.info,  Node: C API<48>,  Prev: IDLE<33>,  Up: Python 3 9 0 alpha 4

1.23.55.9 C API
...............

   - bpo-35081(1): Move the ‘bytes_methods.h’ header file to the
     internal C API as ‘pycore_bytes_methods.h’: it only contains
     private symbols (prefixed by ‘_Py’), except of the
     ‘PyDoc_STRVAR_shared()’ macro.

   - bpo-35081(2): Move the ‘dtoa.h’ header file to the internal C API
     as ‘pycore_dtoa.h’: it only contains private functions (prefixed by
     ‘_Py’).  The *note math: 8e. and *note cmath: 18. modules must now
     be compiled with the ‘Py_BUILD_CORE’ macro defined.

   - bpo-39573(3): Add *note Py_SET_SIZE(): 786. function to set the
     size of an object.

   - bpo-39500(4): *note PyUnicode_IsIdentifier(): 1b2f. does not call
     *note Py_FatalError(): 98d. anymore if the string is not ready.

   - bpo-39573(5): Add *note Py_SET_TYPE(): 784. function to set the
     type of an object.

   - bpo-39573(6): Add a *note Py_SET_REFCNT(): 8b2. function to set the
     reference counter of an object.

   - bpo-39542(7): Convert *note PyType_HasFeature(): 1ae3, *note
     PyType_Check(): 1b30. and *note PyType_CheckExact(): 1b31. macros
     to static inline functions.

   - bpo-39542(8): In the limited C API, ‘PyObject_INIT()’ and
     ‘PyObject_INIT_VAR()’ are now defined as aliases to *note
     PyObject_Init(): a79. and *note PyObject_InitVar(): 1ae7. to make
     their implementation opaque.  It avoids to leak implementation
     details in the limited C API. Exclude the following functions from
     the limited C API: ‘_Py_NewReference()’, ‘_Py_ForgetReference()’,
     ‘_PyTraceMalloc_NewReference()’ and ‘_Py_GetRefTotal()’.

   - bpo-39542(9): Exclude trashcan mechanism from the limited C API: it
     requires access to PyTypeObject and PyThreadState structure fields,
     whereas these structures are opaque in the limited C API.

   - bpo-39511(10): The *note PyThreadState_Clear(): 1729. function now
     calls the ‘PyThreadState.on_delete’ callback.  Previously, that
     happened in *note PyThreadState_Delete(): 1b32.

   - bpo-38076(11): Fix to clear the interpreter state only after
     clearing module globals to guarantee module state access from C
     Extensions during runtime destruction

   - bpo-39245(12): The Vectorcall API (PEP 590) was made public, adding
     the functions ‘PyObject_Vectorcall’, ‘PyObject_VectorcallMethod’,
     ‘PyVectorcall_Function’, ‘PyObject_CallOneArg’,
     ‘PyObject_CallMethodNoArgs’, ‘PyObject_CallMethodOneArg’,
     ‘PyObject_FastCallDict’, and the flag ‘Py_TPFLAGS_HAVE_VECTORCALL’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39500

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39573

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39542

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39542

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39542

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39511

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38076

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39245


File: python.info,  Node: Python 3 9 0 alpha 3,  Next: Python 3 9 0 alpha 2,  Prev: Python 3 9 0 alpha 4,  Up: Changelog

1.23.56 Python 3.9.0 alpha 3
----------------------------

'Release date: 2020-01-24'

* Menu:

* Core and Builtins: Core and Builtins<129>.
* Library: Library<131>.
* Documentation: Documentation<47>.
* Build: Build<54>.
* IDLE: IDLE<34>.
* C API: C API<49>.


File: python.info,  Node: Core and Builtins<129>,  Next: Library<131>,  Up: Python 3 9 0 alpha 3

1.23.56.1 Core and Builtins
...........................

   - bpo-39427(1): Document all possibilities for the ‘-X’ options in
     the command line help section.  Patch by Pablo Galindo.

   - bpo-39421(2): Fix possible crashes when operating with the
     functions in the *note heapq: 69. module and custom comparison
     operators.

   - bpo-39386(3): Prevent double awaiting of async iterator.

   - bpo-17005(4): Add ‘functools.TopologicalSorter’ to the *note
     functools: 5f. module to offers functionality to perform
     topological sorting of graphs.  Patch by Pablo Galindo, Tim Peters
     and Larry Hastings.

   - bpo-39320(5): Replace four complex bytecodes for building sequences
     with three simpler ones.

     The following four bytecodes have been removed:

        * BUILD_LIST_UNPACK

        * BUILD_TUPLE_UNPACK

        * BUILD_SET_UNPACK

        * BUILD_TUPLE_UNPACK_WITH_CALL

     The following three bytecodes have been added:

        * LIST_TO_TUPLE

        * LIST_EXTEND

        * SET_UPDATE

   - bpo-39336(6): Import loaders which publish immutable module objects
     can now publish immutable packages in addition to individual
     modules.

   - bpo-39322(7): Added a new function *note gc.is_finalized(): 906. to
     check if an object has been finalized by the garbage collector.
     Patch by Pablo Galindo.

   - bpo-39048(8): Improve the displayed error message when incorrect
     types are passed to ‘async with’ statements by looking up the
     ‘__aenter__()’ special method before the ‘__aexit__()’ special
     method when entering an asynchronous context manager.  Patch by
     Géry Ogam.

   - bpo-39235(9): Fix AST end location for lone generator expression in
     function call, e.g.  f(i for i in a).

   - bpo-39209(10): Correctly handle multi-line tokens in interactive
     mode.  Patch by Pablo Galindo.

   - bpo-1635741(11): Port _json extension module to multiphase
     initialization ( PEP 489(12)).

   - bpo-39216(13): Fix constant folding optimization for positional
     only arguments - by Anthony Sottile.

   - bpo-39215(14): Fix ‘SystemError’ when nested function has
     annotation on positional-only argument - by Anthony Sottile.

   - bpo-39200(15): Correct the error message when calling the *note
     min(): f3f. or *note max(): f40. with no arguments.  Patch by
     Donghee Na.

   - bpo-39200(16): Correct the error message when trying to construct
     *note range: 94d. objects with no arguments.  Patch by Pablo
     Galindo.

   - bpo-39166(17): Fix incorrect line execution reporting in trace
     functions when tracing the last iteration of asynchronous for
     loops.  Patch by Pablo Galindo.

   - bpo-39114(18): Fix incorrect line execution reporting in trace
     functions when tracing exception handlers with name binding.  Patch
     by Pablo Galindo.

   - bpo-39156(19): Split the COMPARE_OP bytecode instruction into four
     distinct instructions.

        * COMPARE_OP for rich comparisons

        * IS_OP for ‘is’ and ‘is not’ tests

        * CONTAINS_OP for ‘in’ and ‘is not’ tests

        * JUMP_IF_NOT_EXC_MATCH for checking exceptions in ‘try-except’
          statements.

     This improves the clarity of the interpreter and should provide a
     modest speedup.

   - bpo-38588(20): Fix possible crashes in dict and list when calling
     *note PyObject_RichCompareBool(): 1b35.

   - bpo-13601(21): By default, ‘sys.stderr’ is line-buffered now, even
     if ‘stderr’ is redirected to a file.  You can still make
     ‘sys.stderr’ unbuffered by passing the *note -u: 1b36. command-line
     option or setting the *note PYTHONUNBUFFERED: 1b37. environment
     variable.

     (Contributed by Jendrik Seipp in bpo-13601(22).)

   - bpo-38610(23): Fix possible crashes in several list methods by
     holding strong references to list elements when calling *note
     PyObject_RichCompareBool(): 1b35.

   - bpo-32021(24): Include brotli .br encoding in mimetypes
     encodings_map

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39427

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39421

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39386

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17005

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39320

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39336

   (7) https://bugs.python.org/issue?@action=redirect&bpo=39322

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39048

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39235

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39209

   (11) https://bugs.python.org/issue?@action=redirect&bpo=1635741

   (12) https://peps.python.org/pep-0489/

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39216

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39215

   (15) https://bugs.python.org/issue?@action=redirect&bpo=39200

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39200

   (17) https://bugs.python.org/issue?@action=redirect&bpo=39166

   (18) https://bugs.python.org/issue?@action=redirect&bpo=39114

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39156

   (20) https://bugs.python.org/issue?@action=redirect&bpo=38588

   (21) https://bugs.python.org/issue?@action=redirect&bpo=13601

   (22) https://bugs.python.org/issue?@action=redirect&bpo=13601

   (23) https://bugs.python.org/issue?@action=redirect&bpo=38610

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32021


File: python.info,  Node: Library<131>,  Next: Documentation<47>,  Prev: Core and Builtins<129>,  Up: Python 3 9 0 alpha 3

1.23.56.2 Library
.................

   - bpo-39430(1): Fixed race condition in lazy imports in *note
     tarfile: de.

   - bpo-39413(2): The *note os.unsetenv(): 924. function is now also
     available on Windows.

   - bpo-39390(3): Fixed a regression with the ‘ignore’ callback of
     *note shutil.copytree(): a36.  The argument types are now ‘str’ and
     ‘List[str]’ again.

   - bpo-39395(4): The *note os.putenv(): 925. and *note os.unsetenv():
     924. functions are now always available.

   - bpo-39406(5): If ‘setenv()’ C function is available, *note
     os.putenv(): 925. is now implemented with ‘setenv()’ instead of
     ‘putenv()’, so Python doesn’t have to handle the environment
     variable memory.

   - bpo-39396(6): Fix ‘math.nextafter(-0.0, +0.0)’ on AIX 7.1.

   - bpo-29435(7): Allow *note tarfile.is_tarfile(): 1980. to be used
     with file and file-like objects, like *note zipfile.is_zipfile():
     1374.  Patch by William Woodruff.

   - bpo-39377(8): Removed ‘encoding’ option from *note json.loads():
     95f.  It has been deprecated since Python 3.1.

   - bpo-39389(9): Write accurate compression level metadata in *note
     gzip: 67. archives, rather than always signaling maximum
     compression.

   - bpo-39366(10): The previously deprecated ‘xpath()’ and ‘xgtitle()’
     methods of ‘nntplib.NNTP’ have been removed.

   - bpo-39357(11): Remove the 'buffering' parameter of *note
     bz2.BZ2File: 86d.  Since Python 3.0, it was ignored and using it
     was emitting *note DeprecationWarning: 1a5.  Pass an open file
     object, to control how the file is opened.  The 'compresslevel'
     parameter becomes keyword-only.

   - bpo-39353(12): Deprecate binhex4 and hexbin4 standards.  Deprecate
     the ‘binhex’ module and the following *note binascii: 10.
     functions: ‘b2a_hqx()’, ‘a2b_hqx()’, ‘rlecode_hqx()’,
     ‘rledecode_hqx()’, *note crc_hqx(): 737.

   - bpo-39351(13): Remove ‘base64.encodestring()’ and
     ‘base64.decodestring()’, aliases deprecated since Python 3.1: use
     *note base64.encodebytes(): 95d. and *note base64.decodebytes():
     95e. instead.

   - bpo-39350(14): Remove ‘fractions.gcd()’ function, deprecated since
     Python 3.5 (bpo-22486(15)): use *note math.gcd(): 919. instead.

   - bpo-39329(16): *note LMTP: 939. constructor now has an optional
     'timeout' parameter.  Patch by Donghee Na.

   - bpo-39313(17): Add a new ‘exec_function’ option ('–exec-function'
     in the CLI) to ‘RefactoringTool’ for making ‘exec’ a function.
     Patch by Batuhan Taskaya.

   - bpo-39259(18): *note FTP_TLS: 904. and ‘FTP_TLS’ now raise a *note
     ValueError: 202. if the given timeout for their constructor is zero
     to prevent the creation of a non-blocking socket.  Patch by Donghee
     Na.

   - bpo-39259(19): *note SMTP: 937. and *note SMTP_SSL: 938. now raise
     a *note ValueError: 202. if the given timeout for their constructor
     is zero to prevent the creation of a non-blocking socket.  Patch by
     Donghee Na.

   - bpo-39310(20): Add *note math.ulp(): 91b.: return the value of the
     least significant bit of a float.

   - bpo-39297(21): Improved performance of importlib.metadata
     distribution discovery and resilients to inaccessible sys.path
     entries (importlib_metadata v1.4.0).

   - bpo-39259(22): ‘NNTP’ and ‘NNTP_SSL’ now raise a *note ValueError:
     202. if the given timeout for their constructor is zero to prevent
     the creation of a non-blocking socket.  Patch by Donghee Na.

   - bpo-38901(23): When you specify prompt=’.’ or equivalently python
     -m venv –prompt .  … the basename of the current directory is used
     to set the created venv’s prompt when it’s activated.

   - bpo-39288(24): Add *note math.nextafter(): 49b.: return the next
     floating-point value after 'x' towards 'y'.

   - bpo-39259(25): *note POP3: 92d. and *note POP3_SSL: 92e. now raise
     a *note ValueError: 202. if the given timeout for their constructor
     is zero to prevent the creation of a non-blocking socket.  Patch by
     Donghee Na.

   - bpo-39242(26): Updated the Gmane domain from news.gmane.org to
     news.gmane.io which is used for examples of ‘NNTP’ news reader
     server and nntplib tests.

   - bpo-35292(27): Proxy the ‘SimpleHTTPRequestHandler.guess_type’ to
     ‘mimetypes.guess_type’ so the ‘mimetypes.init’ is called lazily to
     avoid unnecessary costs when *note http.server: 72. module is
     imported.

   - bpo-39239(28): The *note select.epoll.unregister(): 964. method no
     longer ignores the *note EBADF: 965. error.

   - bpo-38907(29): In http.server script, restore binding to IPv4 on
     Windows.

   - bpo-39152(30): Fix ttk.Scale.configure([name]) to return
     configuration tuple for name or all options.  Giovanni Lombardo
     contributed part of the patch.

   - bpo-39198(31): If an exception were to be thrown in
     ‘Logger.isEnabledFor’ (say, by asyncio timeouts or stopit) , the
     ‘logging’ global lock may not be released appropriately, resulting
     in deadlock.  This change wraps that block of code with
     ‘try...finally’ to ensure the lock is released.

   - bpo-39191(32): Perform a check for running loop before starting a
     new task in ‘loop.run_until_complete()’ to fail fast; it prevents
     the side effect of new task spawning before exception raising.

   - bpo-38871(33): Correctly parenthesize filter-based statements that
     contain lambda expressions in ‘lib2to3’.  Patch by Donghee Na.

   - bpo-39142(34): A change was made to logging.config.dictConfig to
     avoid converting instances of named tuples to ConvertingTuple.
     It’s assumed that named tuples are too specialised to be treated
     like ordinary tuples; if a user of named tuples requires
     ConvertingTuple functionality, they will have to implement that
     themselves in their named tuple class.

   - bpo-39158(35): ast.literal_eval() now supports empty sets.

   - bpo-39129(36): Fix import path for ‘asyncio.TimeoutError’

   - bpo-39057(37): ‘urllib.request.proxy_bypass_environment()’ now
     ignores leading dots and no longer ignores a trailing newline.

   - bpo-39056(38): Fixed handling invalid warning category in the -W
     option.  No longer import the re module if it is not needed.

   - bpo-39055(39): *note base64.b64decode(): 15af. with ‘validate=True’
     raises now a binascii.Error if the input ends with a single ‘\n’.

   - bpo-21600(40): Fix ‘mock.patch.stopall()’ to stop active patches
     that were created with ‘mock.patch.dict()’.

   - bpo-39019(41): Implement dummy ‘__class_getitem__’ for *note
     tempfile.SpooledTemporaryFile: 696.

   - bpo-39019(42): Implement dummy ‘__class_getitem__’ for
     ‘subprocess.Popen’, ‘subprocess.CompletedProcess’

   - bpo-38914(43): Adjusted the wording of the warning issued by
     distutils’ ‘check’ command when the ‘author’ and ‘maintainer’
     fields are supplied but no corresponding e-mail field
     (‘author_email’ or ‘maintainer_email’) is found.  The wording now
     reflects the fact that these fields are suggested, but not
     required.  Patch by Juergen Gmach.

   - bpo-38878(44): Fixed __subclasshook__ of *note os.PathLike: c72. to
     return a correct result upon inheritance.  Patch by Bar Harel.

   - bpo-38615(45): *note IMAP4: 90c. and *note IMAP4_SSL: 90d. now have
     an optional 'timeout' parameter for their constructors.  Also, the
     *note open(): 90e. method now has an optional 'timeout' parameter
     with this change.  The overridden methods of ‘IMAP4_SSL’ and *note
     IMAP4_stream: 90f. were applied to this change.  Patch by Donghee
     Na.

   - bpo-35182(46): Fixed ‘Popen.communicate()’ subsequent call crash
     when the child process has already closed any piped standard
     stream, but still continues to be running.  Patch by Andriy
     Maletsky.

   - bpo-38630(47): On Unix, *note subprocess.Popen.send_signal(): 142c.
     now polls the process status.  Polling reduces the risk of sending
     a signal to the wrong process if the process completed, the *note
     subprocess.Popen.returncode: aa1. attribute is still ‘None’, and
     the pid has been reassigned (recycled) to a new different process.

   - bpo-38536(48): Removes trailing space in formatted currency with
     ‘international=True’ and a locale with symbol following value.
     E.g.  ‘locale.currency(12.34, international=True)’ returned ‘'12,34
     EUR '’ instead of ‘'12,34 EUR'’.

   - bpo-38473(49): Use signature from inner mock for autospecced
     methods attached with ‘unittest.mock.attach_mock()’.  Patch by
     Karthikeyan Singaravelan.

   - bpo-38361(50): Fixed an issue where ‘ident’ could include a leading
     path separator when *note syslog.openlog(): 541. was called without
     arguments.

   - bpo-38293(51): Add *note copy.copy(): 537. and *note
     copy.deepcopy(): b8a. support to *note property(): 194. objects.

   - bpo-37958(52): Added the pstats.Stats.get_profile_dict() method to
     return the profile data as a StatsProfile instance.

   - bpo-28367(53): Termios magic constants for the following baud
     rates: - B500000 - B576000 - B921600 - B1000000 - B1152000 -
     B1500000 - B2000000 - B2500000 - B3000000 - B3500000 - B4000000
     Patch by Andrey Smirnov

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39430

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39413

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39390

   (4) https://bugs.python.org/issue?@action=redirect&bpo=39395

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39406

   (6) https://bugs.python.org/issue?@action=redirect&bpo=39396

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29435

   (8) https://bugs.python.org/issue?@action=redirect&bpo=39377

   (9) https://bugs.python.org/issue?@action=redirect&bpo=39389

   (10) https://bugs.python.org/issue?@action=redirect&bpo=39366

   (11) https://bugs.python.org/issue?@action=redirect&bpo=39357

   (12) https://bugs.python.org/issue?@action=redirect&bpo=39353

   (13) https://bugs.python.org/issue?@action=redirect&bpo=39351

   (14) https://bugs.python.org/issue?@action=redirect&bpo=39350

   (15) https://bugs.python.org/issue?@action=redirect&bpo=22486

   (16) https://bugs.python.org/issue?@action=redirect&bpo=39329

   (17) https://bugs.python.org/issue?@action=redirect&bpo=39313

   (18) https://bugs.python.org/issue?@action=redirect&bpo=39259

   (19) https://bugs.python.org/issue?@action=redirect&bpo=39259

   (20) https://bugs.python.org/issue?@action=redirect&bpo=39310

   (21) https://bugs.python.org/issue?@action=redirect&bpo=39297

   (22) https://bugs.python.org/issue?@action=redirect&bpo=39259

   (23) https://bugs.python.org/issue?@action=redirect&bpo=38901

   (24) https://bugs.python.org/issue?@action=redirect&bpo=39288

   (25) https://bugs.python.org/issue?@action=redirect&bpo=39259

   (26) https://bugs.python.org/issue?@action=redirect&bpo=39242

   (27) https://bugs.python.org/issue?@action=redirect&bpo=35292

   (28) https://bugs.python.org/issue?@action=redirect&bpo=39239

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38907

   (30) https://bugs.python.org/issue?@action=redirect&bpo=39152

   (31) https://bugs.python.org/issue?@action=redirect&bpo=39198

   (32) https://bugs.python.org/issue?@action=redirect&bpo=39191

   (33) https://bugs.python.org/issue?@action=redirect&bpo=38871

   (34) https://bugs.python.org/issue?@action=redirect&bpo=39142

   (35) https://bugs.python.org/issue?@action=redirect&bpo=39158

   (36) https://bugs.python.org/issue?@action=redirect&bpo=39129

   (37) https://bugs.python.org/issue?@action=redirect&bpo=39057

   (38) https://bugs.python.org/issue?@action=redirect&bpo=39056

   (39) https://bugs.python.org/issue?@action=redirect&bpo=39055

   (40) https://bugs.python.org/issue?@action=redirect&bpo=21600

   (41) https://bugs.python.org/issue?@action=redirect&bpo=39019

   (42) https://bugs.python.org/issue?@action=redirect&bpo=39019

   (43) https://bugs.python.org/issue?@action=redirect&bpo=38914

   (44) https://bugs.python.org/issue?@action=redirect&bpo=38878

   (45) https://bugs.python.org/issue?@action=redirect&bpo=38615

   (46) https://bugs.python.org/issue?@action=redirect&bpo=35182

   (47) https://bugs.python.org/issue?@action=redirect&bpo=38630

   (48) https://bugs.python.org/issue?@action=redirect&bpo=38536

   (49) https://bugs.python.org/issue?@action=redirect&bpo=38473

   (50) https://bugs.python.org/issue?@action=redirect&bpo=38361

   (51) https://bugs.python.org/issue?@action=redirect&bpo=38293

   (52) https://bugs.python.org/issue?@action=redirect&bpo=37958

   (53) https://bugs.python.org/issue?@action=redirect&bpo=28367


File: python.info,  Node: Documentation<47>,  Next: Build<54>,  Prev: Library<131>,  Up: Python 3 9 0 alpha 3

1.23.56.3 Documentation
.......................

   - bpo-39381(1): Mention in docs that *note asyncio.get_event_loop():
     2c2. implicitly creates new event loop only if called from the main
     thread.

   - bpo-38918(2): Add an entry for ‘__module__’ in the “function” &
     “method” sections of the *note inspect: 7e. docs’ *note Types and
     members: 1b3a. table.

   - bpo-3530(3): In the *note ast: 8. module documentation, fix a
     misleading ‘NodeTransformer’ example and add advice on when to use
     the ‘fix_missing_locations’ function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39381

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38918

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3530


File: python.info,  Node: Build<54>,  Next: IDLE<34>,  Prev: Documentation<47>,  Up: Python 3 9 0 alpha 3

1.23.56.4 Build
...............

   - bpo-39395(1): On non-Windows platforms, the ‘setenv()’ and
     ‘unsetenv()’ functions are now required to build Python.

   - bpo-39160(2): Updated the documentation in ‘./configure --help’ to
     show default values, reference documentation where required and add
     additional explanation where needed.

   - bpo-39144(3): The ctags and etags build targets both include
     Modules/_ctypes and Python standard library source files.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39395

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39160

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39144


File: python.info,  Node: IDLE<34>,  Next: C API<49>,  Prev: Build<54>,  Up: Python 3 9 0 alpha 3

1.23.56.5 IDLE
..............

   - bpo-39050(1): Make IDLE Settings dialog Help button work again.

   - bpo-34118(2): Tag memoryview, range, and tuple as classes, the same
     as list, etcetera, in the library manual built-in functions list.

   - bpo-32989(3): Add tests for editor newline_and_indent_event method.
     Remove dead code from pyparse find_good_parse_start method.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39050

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34118

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32989


File: python.info,  Node: C API<49>,  Prev: IDLE<34>,  Up: Python 3 9 0 alpha 3

1.23.56.6 C API
...............

   - bpo-39372(1): Clean header files of interfaces defined but with no
     implementation.  The public API symbols being removed are:
     ‘_PyBytes_InsertThousandsGroupingLocale’,
     ‘_PyBytes_InsertThousandsGrouping’, ‘_Py_InitializeFromArgs’,
     ‘_Py_InitializeFromWideArgs’, ‘_PyFloat_Repr’, ‘_PyFloat_Digits’,
     ‘_PyFloat_DigitsInit’, ‘PyFrame_ExtendStack’,
     ‘_PyAIterWrapper_Type’, ‘PyNullImporter_Type’, ‘PyCmpWrapper_Type’,
     ‘PySortWrapper_Type’, ‘PyNoArgsFunction’.

   - bpo-39164(2): Add a private ‘_PyErr_GetExcInfo()’ function to
     retrieve exception information of the specified Python thread
     state.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39372

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39164


File: python.info,  Node: Python 3 9 0 alpha 2,  Next: Python 3 9 0 alpha 1,  Prev: Python 3 9 0 alpha 3,  Up: Changelog

1.23.57 Python 3.9.0 alpha 2
----------------------------

'Release date: 2019-12-18'

* Menu:

* Security: Security<38>.
* Core and Builtins: Core and Builtins<130>.
* Library: Library<132>.
* Documentation: Documentation<48>.
* Tests: Tests<50>.
* Build: Build<55>.
* Windows: Windows<47>.
* macOS: macOS<38>.
* IDLE: IDLE<35>.
* C API: C API<50>.


File: python.info,  Node: Security<38>,  Next: Core and Builtins<130>,  Up: Python 3 9 0 alpha 2

1.23.57.1 Security
..................

   - bpo-38945(1): Newline characters have been escaped when performing
     uu encoding to prevent them from overflowing into to content
     section of the encoded file.  This prevents malicious or accidental
     modification of data during the decoding process.

   - bpo-37228(2): Due to significant security concerns, the
     'reuse_address' parameter of *note
     asyncio.loop.create_datagram_endpoint(): 736. is no longer
     supported.  This is because of the behavior of ‘SO_REUSEADDR’ in
     UDP. For more details, see the documentation for
     ‘loop.create_datagram_endpoint()’.  (Contributed by Kyle Stanley,
     Antoine Pitrou, and Yury Selivanov in bpo-37228(3).)

   - bpo-38804(4): Fixes a ReDoS vulnerability in *note http.cookiejar:
     70.  Patch by Ben Caller.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38945

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37228

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37228

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38804


File: python.info,  Node: Core and Builtins<130>,  Next: Library<132>,  Prev: Security<38>,  Up: Python 3 9 0 alpha 2

1.23.57.2 Core and Builtins
...........................

   - bpo-39028(1): Slightly improve the speed of keyword argument
     parsing with many kwargs by strengthening the assumption that
     kwargs are interned strings.

   - bpo-39080(2): Fix the value of 'end_col_offset' for Starred
     Expression AST nodes when they are among the elements in the 'args'
     attribute of Call AST nodes.

   - bpo-39031(3): When parsing an “elif” node, lineno and col_offset of
     the node now point to the “elif” keyword and not to its condition,
     making it consistent with the “if” node.  Patch by Lysandros
     Nikolaou.

   - bpo-20443(4): In Python 3.9.0a1, sys.argv[0] was made an absolute
     path if a filename was specified on the command line.  Revert this
     change, since most users expect sys.argv to be unmodified.

   - bpo-39008(5): *note PySys_Audit(): 372. now requires ‘Py_ssize_t’
     to be used for size arguments in the format string, regardless of
     whether ‘PY_SSIZE_T_CLEAN’ was defined at include time.

   - bpo-38673(6): In REPL mode, don’t switch to PS2 if the line starts
     with comment or whitespace.  Based on work by Batuhan Taşkaya.

   - bpo-38922(7): Calling ‘replace’ on a code object now raises the
     ‘code.__new__’ audit event.

   - bpo-38920(8): Add audit hooks for when *note sys.excepthook(): 811.
     and *note sys.unraisablehook(): 1f7. are invoked.

   - bpo-38892(9): Improve documentation for audit events table and
     functions.

   - bpo-38852(10): Set the thread stack size to 8 Mb for debug builds
     on android platforms.

   - bpo-38858(11): Each Python subinterpreter now has its own “small
     integer singletons”: numbers in [-5; 257] range.  It is no longer
     possible to change the number of small integers at build time by
     overriding ‘NSMALLNEGINTS’ and ‘NSMALLPOSINTS’ macros: macros
     should now be modified manually in ‘pycore_pystate.h’ header file.

   - bpo-36854(12): The garbage collector state becomes per interpreter
     (‘PyInterpreterState.gc’), rather than being global
     (‘_PyRuntimeState.gc’).

   - bpo-38835(13): The ‘PyFPE_START_PROTECT()’ and
     ‘PyFPE_END_PROTECT()’ macros are empty: they have been doing
     nothing for the last year, so stop using them.

   - bpo-38328(14): Sped up the creation time of constant *note list:
     614. and *note set: 5dc. displays.  Patch by Brandt Bucher.

   - bpo-38707(15): ‘MainThread.native_id’ is now correctly reset in
     child processes spawned using *note multiprocessing.Process: b75,
     instead of retaining the parent’s value.

   - bpo-38629(16): Added ‘__floor__’ and ‘__ceil__’ methods to float
     object.  Patch by Batuhan Taşkaya.

   - bpo-27145(17): int + int and int - int operators can now return
     small integer singletons.  Patch by hongweipeng.

   - bpo-38021(18): Provide a platform tag for AIX that is sufficient
     for PEP425 binary distribution identification.  Patch by Michael
     Felt.

   - bpo-35409(19): Ignore GeneratorExit exceptions when throwing an
     exception into the aclose coroutine of an asynchronous generator.

   - bpo-33387(20): Removed WITH_CLEANUP_START, WITH_CLEANUP_FINISH,
     BEGIN_FINALLY, END_FINALLY, CALL_FINALLY and POP_FINALLY bytecodes.
     Replaced with RERAISE and WITH_EXCEPT_START bytecodes.  The
     compiler now generates different code for exceptional and
     non-exceptional branches for ‘with’ and ‘try-except’ statements.
     For ‘try-finally’ statements the ‘finally’ block is replicated for
     each exit from the ‘try’ body.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39028

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39080

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39031

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20443

   (5) https://bugs.python.org/issue?@action=redirect&bpo=39008

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38673

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38922

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38920

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38892

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38852

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38858

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36854

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38835

   (14) https://bugs.python.org/issue?@action=redirect&bpo=38328

   (15) https://bugs.python.org/issue?@action=redirect&bpo=38707

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38629

   (17) https://bugs.python.org/issue?@action=redirect&bpo=27145

   (18) https://bugs.python.org/issue?@action=redirect&bpo=38021

   (19) https://bugs.python.org/issue?@action=redirect&bpo=35409

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33387


File: python.info,  Node: Library<132>,  Next: Documentation<48>,  Prev: Core and Builtins<130>,  Up: Python 3 9 0 alpha 2

1.23.57.3 Library
.................

   - bpo-39033(1): Fix *note NameError: 442. in *note zipimport: 132.
     Patch by Karthikeyan Singaravelan.

   - bpo-39022(2): Update importlib.metadata to include improvements
     from importlib_metadata 1.3 including better serialization of
     EntryPoints and improved documentation for custom finders.

   - bpo-39006(3): Fix asyncio when the ssl module is missing: only
     check for ssl.SSLSocket instance if the ssl module is available.

   - bpo-38708(4): Fix a potential IndexError in email parser when
     parsing an empty msg-id.

   - bpo-38698(5): Add a new ‘InvalidMessageID’ token to email parser to
     represent invalid Message-ID headers.  Also, add defects when there
     is remaining value after parsing the header.

   - bpo-38994(6): Implement ‘__class_getitem__’ for ‘os.PathLike’,
     ‘pathlib.Path’.

   - bpo-38979(7): Return class from ‘ContextVar.__class_getitem__’ to
     simplify subclassing.

   - bpo-38978(8): Implement ‘__class_getitem__’ on asyncio objects
     (Future, Task, Queue).  Patch by Batuhan Taskaya.

   - bpo-38916(9): *note array.array: 1a0.: Remove ‘tostring()’ and
     ‘fromstring()’ methods.  They were aliases to ‘tobytes()’ and
     ‘frombytes()’, deprecated since Python 3.2.

   - bpo-38986(10): Make repr of C accelerated TaskWakeupMethWrapper the
     same as of pure Python version.

   - bpo-38982(11): Fix asyncio ‘PidfdChildWatcher’: handle ‘waitpid()’
     error.  If ‘waitpid()’ is called elsewhere, ‘waitpid()’ call fails
     with *note ChildProcessError: 1096.: use return code 255 in this
     case, and log a warning.  It ensures that the pidfd file descriptor
     is closed if this error occurs.

   - bpo-38529(12): Drop too noisy asyncio warning about deletion of a
     stream without explicit ‘.close()’ call.

   - bpo-27413(13): Added ability to pass through ‘ensure_ascii’ options
     to json.dumps in the ‘json.tool’ command-line interface.

   - bpo-38634(14): The *note readline: ba. module now detects if Python
     is linked to libedit at runtime on all platforms.  Previously, the
     check was only done on macOS.

   - bpo-33684(15): Fix ‘json.tool’ failed to read a JSON file with
     non-ASCII characters when locale encoding is not UTF-8.

   - bpo-38698(16): Prevent UnboundLocalError to pop up in
     parse_message_id.

     parse_message_id() was improperly using a token defined inside an
     exception handler, which was raising ‘UnboundLocalError’ on parsing
     an invalid value.  Patch by Claudiu Popa.

   - bpo-38927(17): Use ‘python -m pip’ instead of ‘pip’ to upgrade
     dependencies in venv.

   - bpo-26730(18): Fix ‘SpooledTemporaryFile.rollover()’ might corrupt
     the file when it is in text mode.  Patch by Serhiy Storchaka.

   - bpo-38881(19): random.choices() now raises a ValueError when all
     the weights are zero.

   - bpo-38876(20): Raise pickle.UnpicklingError when loading an item
     from memo for invalid input.

     The previous code was raising a ‘KeyError’ for both the Python and
     C implementation.  This was caused by the specified index of an
     invalid input which did not exist in the memo structure, where the
     pickle stores what objects it has seen.  The malformed input would
     have caused either a ‘BINGET’ or ‘LONG_BINGET’ load from the memo,
     leading to a ‘KeyError’ as the determined index was bogus.  Patch
     by Claudiu Popa.

   - bpo-38688(21): Calling func:‘shutil.copytree’ to copy a directory
     tree from one directory to another subdirectory resulted in an
     endless loop and a RecursionError.  A fix was added to consume an
     iterator and create the list of the entries to be copied, avoiding
     the recursion for newly created directories.  Patch by Bruno P.
     Kinoshita.

   - bpo-38863(22): Improve ‘is_cgi()’ function in *note http.server:
     72, which enables processing the case that cgi directory is a child
     of another directory other than root.

   - bpo-37838(23): *note typing.get_type_hints(): 6b4. properly handles
     functions decorated with *note functools.wraps(): f96.

   - bpo-38870(24): Expose *note ast.unparse(): 8ee. as a function of
     the *note ast: 8. module that can be used to unparse an *note
     ast.AST: 1a6. object and produce a string with code that would
     produce an equivalent ‘ast.AST’ object when parsed.  Patch by Pablo
     Galindo and Batuhan Taskaya.

   - bpo-38859(25): AsyncMock now returns StopAsyncIteration on the
     exhaustion of a side_effects iterable.  Since PEP-479 its
     Impossible to raise a StopIteration exception from a coroutine.

   - bpo-38857(26): AsyncMock fix for return values that are awaitable
     types.  This also covers side_effect iterable values that happened
     to be awaitable, and wraps callables that return an awaitable type.
     Before these awaitables were being awaited instead of being
     returned as is.

   - bpo-38834(27): *note typing.TypedDict: 162. subclasses now track
     which keys are optional using the ‘__required_keys__’ and
     ‘__optional_keys__’ attributes, to enable runtime validation by
     downstream projects.  Patch by Zac Hatfield-Dodds.

   - bpo-38821(28): Fix unhandled exceptions in *note argparse: 6. when
     internationalizing error messages for arguments with ‘nargs’ set to
     special (non-integer) values.  Patch by Federico Bond.

   - bpo-38820(29): Make Python compatible with OpenSSL 3.0.0.  *note
     ssl.SSLSocket.getpeercert(): ff1. no longer returns IPv6 addresses
     with a trailing new line.

   - bpo-38811(30): Fix an unhandled exception in *note pathlib: a4.
     when *note os.link(): 1133. is missing.  Patch by Toke
     Høiland-Jørgensen.

   - bpo-38686(31): Added support for multiple ‘qop’ values in *note
     urllib.request.AbstractDigestAuthHandler: 1b14.

   - bpo-38712(32): Add the Linux-specific *note
     signal.pidfd_send_signal(): 935. function, which allows sending a
     signal to a process identified by a file descriptor rather than a
     pid.

   - bpo-38348(33): Add ‘-i’ and ‘--indent’ (indentation level), and
     ‘--no-type-comments’ (type comments) command line options to ast
     parsing tool.

   - bpo-37523(34): Change ‘zipfile.ZipExtFile’ to raise ‘ValueError’
     when trying to access the underlying file object after it has been
     closed.  This new behavior is consistent with how accessing closed
     files is handled in other parts of Python.

   - bpo-38045(35): Improve the performance of ‘enum._decompose()’ in
     *note enum: 56.  Patch by hongweipeng.

   - bpo-36820(36): Break cycle generated when saving an exception in
     socket.py, codeop.py and dyld.py as they keep alive not only the
     exception but user objects through the ‘__traceback__’ attribute.
     Patch by Mario Corchero.

   - bpo-36406(37): Handle namespace packages in *note doctest: 3a.
     Patch by Karthikeyan Singaravelan.

   - bpo-34776(38): Fix dataclasses to support forward references in
     type annotations

   - bpo-20928(39): ElementTree supports recursive XInclude processing.
     Patch by Stefan Behnel.

   - bpo-29636(40): Add whitespace options for formatting JSON with the
     ‘json.tool’ CLI. The following mutually exclusive options are now
     supported: ‘--indent’ for setting the indent level in spaces;
     ‘--tab’ for indenting with tabs; ‘--no-indent’ for suppressing
     newlines; and ‘--compact’ for suppressing all whitespace.  The
     default behavior remains the same as ‘--indent=4’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39033

   (2) https://bugs.python.org/issue?@action=redirect&bpo=39022

   (3) https://bugs.python.org/issue?@action=redirect&bpo=39006

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38708

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38698

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38994

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38979

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38978

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38916

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38986

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38982

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38529

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27413

   (14) https://bugs.python.org/issue?@action=redirect&bpo=38634

   (15) https://bugs.python.org/issue?@action=redirect&bpo=33684

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38698

   (17) https://bugs.python.org/issue?@action=redirect&bpo=38927

   (18) https://bugs.python.org/issue?@action=redirect&bpo=26730

   (19) https://bugs.python.org/issue?@action=redirect&bpo=38881

   (20) https://bugs.python.org/issue?@action=redirect&bpo=38876

   (21) https://bugs.python.org/issue?@action=redirect&bpo=38688

   (22) https://bugs.python.org/issue?@action=redirect&bpo=38863

   (23) https://bugs.python.org/issue?@action=redirect&bpo=37838

   (24) https://bugs.python.org/issue?@action=redirect&bpo=38870

   (25) https://bugs.python.org/issue?@action=redirect&bpo=38859

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38857

   (27) https://bugs.python.org/issue?@action=redirect&bpo=38834

   (28) https://bugs.python.org/issue?@action=redirect&bpo=38821

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38820

   (30) https://bugs.python.org/issue?@action=redirect&bpo=38811

   (31) https://bugs.python.org/issue?@action=redirect&bpo=38686

   (32) https://bugs.python.org/issue?@action=redirect&bpo=38712

   (33) https://bugs.python.org/issue?@action=redirect&bpo=38348

   (34) https://bugs.python.org/issue?@action=redirect&bpo=37523

   (35) https://bugs.python.org/issue?@action=redirect&bpo=38045

   (36) https://bugs.python.org/issue?@action=redirect&bpo=36820

   (37) https://bugs.python.org/issue?@action=redirect&bpo=36406

   (38) https://bugs.python.org/issue?@action=redirect&bpo=34776

   (39) https://bugs.python.org/issue?@action=redirect&bpo=20928

   (40) https://bugs.python.org/issue?@action=redirect&bpo=29636


File: python.info,  Node: Documentation<48>,  Next: Tests<50>,  Prev: Library<132>,  Up: Python 3 9 0 alpha 2

1.23.57.4 Documentation
.......................

   - bpo-38928(1): Correct when venv’s ‘upgrade_dependencies()’ and
     ‘--upgrade-deps’ are added.

   - bpo-38899(2): Update documentation to state that to activate
     virtual environments under fish one should use ‘source’, not ‘.’ as
     documented at
     ‘https://fishshell.com/docs/current/cmds/source.html’.

   - bpo-22377(3): Improves documentation of the values that *note
     datetime.datetime.strptime(): 1714. accepts for ‘%Z’.  Patch by
     Karl Dubost.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38928

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38899

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22377


File: python.info,  Node: Tests<50>,  Next: Build<55>,  Prev: Documentation<48>,  Up: Python 3 9 0 alpha 2

1.23.57.5 Tests
...............

   - bpo-38546(1): Fix test_ressources_gced_in_workers() of
     test_concurrent_futures: explicitly stop the manager to prevent
     leaking a child process running in the background after the test
     completes.

   - bpo-38546(2): Multiprocessing and concurrent.futures tests now stop
     the resource tracker process when tests complete.

   - bpo-38614(3): Replace hardcoded timeout constants in tests with new
     *note test.support: e4. constants: *note LOOPBACK_TIMEOUT: 1b44,
     *note INTERNET_TIMEOUT: 1b45, *note SHORT_TIMEOUT: 1a09. and *note
     LONG_TIMEOUT: 1b46.  It becomes easier to adjust these four timeout
     constants for all tests at once, rather than having to adjust every
     single test file.

   - bpo-38547(4): Fix test_pty: if the process is the session leader,
     closing the master file descriptor raises a SIGHUP signal: simply
     ignore SIGHUP when running the tests.

   - bpo-38992(5): Fix a test for *note math.fsum(): 1422. that was
     failing due to constant folding.

   - bpo-38991(6): *note test.support: e4.: ‘run_python_until_end()’,
     ‘assert_python_ok()’ and ‘assert_python_failure()’ functions no
     longer strip whitespaces from stderr.  Remove
     ‘test.support.strip_python_stderr()’ function.

   - bpo-38965(7): Fix test_faulthandler on GCC 10.  Use the “volatile”
     keyword in ‘faulthandler._stack_overflow()’ to prevent tail call
     optimization on any compiler, rather than relying on compiler
     specific pragma.

   - bpo-38875(8): test_capi: trashcan tests now require the test “cpu”
     resource.

   - bpo-38841(9): Skip asyncio
     test_create_datagram_endpoint_existing_sock_unix on platforms
     lacking a functional bind() for named unix domain sockets.

   - bpo-38692(10): Skip the test_posix.test_pidfd_open() test if
     ‘os.pidfd_open()’ fails with a *note PermissionError: d6b.  This
     situation can happen in a Linux sandbox using a syscall whitelist
     which doesn’t allow the ‘pidfd_open()’ syscall yet.

   - bpo-38839(11): Fix some unused functions in tests.  Patch by Adam
     Johnson.

   - bpo-38669(12): Raise *note TypeError: 2c3. when passing target as a
     string with *note unittest.mock.patch.object(): 169e.

   - bpo-37957(13): test.regrtest now can receive a list of test
     patterns to ignore (using the -i/–ignore argument) or a file with a
     list of patterns to ignore (using the –ignore-file argument).
     Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38546

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38546

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38614

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38547

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38992

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38991

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38965

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38875

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38841

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38692

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38839

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38669

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37957


File: python.info,  Node: Build<55>,  Next: Windows<47>,  Prev: Tests<50>,  Up: Python 3 9 0 alpha 2

1.23.57.6 Build
...............

   - bpo-37404(1): *note asyncio: a. now raises *note TypeError: 2c3.
     when calling incompatible methods with an *note ssl.SSLSocket: 8f3.
     socket.  Patch by Ido Michael.

   - bpo-36500(2): Added an optional “regen” project to the Visual
     Studio solution that will regenerate all grammar, tokens, and
     opcodes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37404

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36500


File: python.info,  Node: Windows<47>,  Next: macOS<38>,  Prev: Build<55>,  Up: Python 3 9 0 alpha 2

1.23.57.7 Windows
.................

   - bpo-39007(1): Add auditing events to functions in *note winreg:
     116.

   - bpo-33125(2): Add support for building and releasing Windows ARM64
     packages.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=39007

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33125


File: python.info,  Node: macOS<38>,  Next: IDLE<35>,  Prev: Windows<47>,  Up: Python 3 9 0 alpha 2

1.23.57.8 macOS
...............

   - bpo-37931(1): Fixed a crash on OSX dynamic builds that occurred
     when re-initializing the posix module after a Py_Finalize if the
     environment had changed since the previous ‘import posix’.  Patch
     by Benoît Hudson.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37931


File: python.info,  Node: IDLE<35>,  Next: C API<50>,  Prev: macOS<38>,  Up: Python 3 9 0 alpha 2

1.23.57.9 IDLE
..............

   - bpo-38944(1): Escape key now closes IDLE completion windows.  Patch
     by Johnny Najera.

   - bpo-38943(2): Fix IDLE autocomplete windows not always appearing on
     some systems.  Patch by Johnny Najera.

   - bpo-38862(3): ‘Strip Trailing Whitespace’ on the Format menu
     removes extra newlines at the end of non-shell files.

   - bpo-38636(4): Fix IDLE Format menu tab toggle and file indent
     width.  These functions (default shortcuts Alt-T and Alt-U) were
     mistakenly disabled in 3.7.5 and 3.8.0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38944

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38943

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38862

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38636


File: python.info,  Node: C API<50>,  Prev: IDLE<35>,  Up: Python 3 9 0 alpha 2

1.23.57.10 C API
................

   - bpo-38896(1): Remove ‘PyUnicode_ClearFreeList()’ function: the
     Unicode free list has been removed in Python 3.3.

   - bpo-37340(2): Remove ‘PyMethod_ClearFreeList()’ and
     ‘PyCFunction_ClearFreeList()’ functions: the free lists of bound
     method objects have been removed.

   - bpo-38835(3): Exclude ‘PyFPE_START_PROTECT()’ and
     ‘PyFPE_END_PROTECT()’ macros of ‘pyfpe.h’ from ‘Py_LIMITED_API’
     (stable API).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38896

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37340

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38835


File: python.info,  Node: Python 3 9 0 alpha 1,  Next: Python 3 8 0 beta 1,  Prev: Python 3 9 0 alpha 2,  Up: Changelog

1.23.58 Python 3.9.0 alpha 1
----------------------------

'Release date: 2019-11-19'

* Menu:

* Security: Security<39>.
* Core and Builtins: Core and Builtins<131>.
* Library: Library<133>.
* Documentation: Documentation<49>.
* Tests: Tests<51>.
* Build: Build<56>.
* Windows: Windows<48>.
* macOS: macOS<39>.
* IDLE: IDLE<36>.
* Tools/Demos: Tools/Demos<26>.
* C API: C API<51>.


File: python.info,  Node: Security<39>,  Next: Core and Builtins<131>,  Up: Python 3 9 0 alpha 1

1.23.58.1 Security
..................

   - bpo-38722(1): *note runpy: be. now uses *note io.open_code(): 15a7.
     to open code files.  Patch by Jason Killen.

   - bpo-38622(2): Add additional audit events for the *note ctypes: 2a.
     module.

   - bpo-38418(3): Fixes audit event for *note os.system(): 14ac. to be
     named ‘os.system’.

   - bpo-38243(4): Escape the server title of *note
     xmlrpc.server.DocXMLRPCServer: 1b4e. when rendering the document
     page as HTML. (Contributed by Donghee Na in bpo-38243(5).)

   - bpo-38174(6): Update vendorized expat library version to 2.2.8,
     which resolves CVE 2019-15903(7).

   - bpo-37764(8): Fixes email._header_value_parser.get_unstructured
     going into an infinite loop for a specific case in which the email
     header does not have trailing whitespace, and the case in which it
     contains an invalid encoded word.  Patch by Ashwin Ramaswami.

   - bpo-37461(9): Fix an infinite loop when parsing specially crafted
     email headers.  Patch by Abhilash Raj.

   - bpo-37363(10): Adds audit events for the range of supported run
     commands (see *note Command line and environment: 1b4f.).

   - bpo-37463(11): ssl.match_hostname() no longer accepts IPv4
     addresses with additional text after the address and only
     quad-dotted notation without trailing whitespaces.  Some
     inet_aton() implementations ignore whitespace and all data after
     whitespace, e.g.  ‘127.0.0.1 whatever’.

   - bpo-37363(12): Adds audit events for *note ensurepip: 55, *note
     ftplib: 5e, *note glob: 64, *note imaplib: 74, ‘nntplib’, *note
     pdb: a5, *note poplib: ac, *note shutil: c5, *note smtplib: ca,
     *note sqlite3: cf, *note subprocess: d6, ‘telnetlib’, *note
     tempfile: e0. and *note webbrowser: 115, as well as *note
     os.listdir(): 113e, *note os.scandir(): a6d. and *note
     breakpoint(): 234.

   - bpo-37364(13): *note io.open_code(): 15a7. is now used when reading
     ‘.pth’ files.

   - bpo-34631(14): Updated OpenSSL to 1.1.1c in Windows installer

   - bpo-34155(15): Fix parsing of invalid email addresses with more
     than one ‘@’ (e.g.  a@b@c.com.)  to not return the part before 2nd
     ‘@’ as valid email address.  Patch by maxking & jpic.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38722

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38622

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38418

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38243

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38243

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38174

   (7) https://www.cve.org/CVERecord?id=CVE-2019-15903

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37764

   (9) https://bugs.python.org/issue?@action=redirect&bpo=37461

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37363

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37463

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37363

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37364

   (14) https://bugs.python.org/issue?@action=redirect&bpo=34631

   (15) https://bugs.python.org/issue?@action=redirect&bpo=34155


File: python.info,  Node: Core and Builtins<131>,  Next: Library<133>,  Prev: Security<39>,  Up: Python 3 9 0 alpha 1

1.23.58.2 Core and Builtins
...........................

   - bpo-38631(1): Replace ‘Py_FatalError()’ call with a regular *note
     RuntimeError: 195. exception in ‘float.__getformat__()’.

   - bpo-38639(2): Optimized *note math.floor(): 140a, *note
     math.ceil(): 140b. and *note math.trunc(): 140c. for floats.

   - bpo-38640(3): Fixed a bug in the compiler that was causing to raise
     in the presence of break statements and continue statements inside
     always false while loops.  Patch by Pablo Galindo.

   - bpo-38613(4): Optimized some set operations (e.g.  ‘|’, ‘^’, and
     ‘-’) of ‘dict_keys’.  ‘d.keys() | other’ was slower than ‘set(d) |
     other’ but they are almost same performance for now.

   - bpo-28029(5): ‘"".replace("", s, n)’ now returns ‘s’ instead of an
     empty string for all non-zero ‘n’.  There are similar changes for
     *note bytes: 1c2. and *note bytearray: 2ea. objects.

   - bpo-38535(6): Fixed line numbers and column offsets for AST nodes
     for calls without arguments in decorators.

   - bpo-38525(7): Fix a segmentation fault when using reverse iterators
     of empty ‘dict’ objects.  Patch by Donghee Na and Inada Naoki.

   - bpo-38465(8): *note bytearray: 2ea, *note array: 1a0. and *note
     mmap: 20b. objects allow now to export more than ‘2**31’ buffers at
     a time.

   - bpo-38469(9): Fixed a bug where the scope of named expressions was
     not being resolved correctly in the presence of the 'global'
     keyword.  Patch by Pablo Galindo.

   - bpo-38437(10): Activate the ‘GC_DEBUG’ macro for debug builds of
     the interpreter (when ‘Py_DEBUG’ is set).  Patch by Pablo Galindo.

   - bpo-38379(11): When the garbage collector makes a collection in
     which some objects resurrect (they are reachable from outside the
     isolated cycles after the finalizers have been executed), do not
     block the collection of all objects that are still unreachable.
     Patch by Pablo Galindo and Tim Peters.

   - bpo-38379(12): When cyclic garbage collection (gc) runs finalizers
     that resurrect unreachable objects, the current gc run ends,
     without collecting any cyclic trash.  However, the statistics
     reported by ‘collect()’ and ‘get_stats()’ claimed that all cyclic
     trash found was collected, and that the resurrected objects were
     collected.  Changed the stats to report that none were collected.

   - bpo-38392(13): In debug mode, *note PyObject_GC_Track(): 1554. now
     calls ‘tp_traverse()’ of the object type to ensure that the object
     is valid: test that objects visited by ‘tp_traverse()’ are valid.

   - bpo-38210(14): Remove unnecessary intersection and update set
     operation in dictview with empty set.  (Contributed by Donghee Na
     in bpo-38210(15).)

   - bpo-38402(16): Check the error from the system’s underlying ‘crypt’
     or ‘crypt_r’.

   - bpo-37474(17): On FreeBSD, Python no longer calls
     ‘fedisableexcept()’ at startup to control the floating-point
     control mode.  The call became useless since FreeBSD 6: it became
     the default mode.

   - bpo-38006(18): Fix a bug due to the interaction of weakrefs and the
     cyclic garbage collector.  We must clear any weakrefs in garbage in
     order to prevent their callbacks from executing and causing a
     crash.

   - bpo-38317(19): Fix warnings options priority:
     ‘PyConfig.warnoptions’ has the highest priority, as stated in the
     PEP 587(20).

   - bpo-38310(21): Predict ‘BUILD_MAP_UNPACK_WITH_CALL’ ->
     ‘CALL_FUNCTION_EX’ opcode pairs in the main interpreter loop.
     Patch by Brandt Bucher.

   - bpo-36871(22): Improve error handling for the assert_has_calls and
     assert_has_awaits methods of mocks.  Fixed a bug where any errors
     encountered while binding the expected calls to the mock’s spec
     were silently swallowed, leading to misleading error output.

   - bpo-11410(23): Better control over symbol visibility is provided
     through use of the visibility attributes available in gcc >= 4.0,
     provided in a uniform way across POSIX and Windows.  The POSIX
     build files have been updated to compile with -fvisibility=hidden,
     minimising exported symbols.

   - bpo-38219(24): Optimized the *note dict: 256. constructor and the
     *note update(): 14b4. method for the case when the argument is a
     dict.

   - bpo-38236(25): Python now dumps path configuration if it fails to
     import the Python codecs of the filesystem and stdio encodings.

   - bpo-38013(26): Allow to call ‘async_generator_athrow().throw(...)’
     even for non-started async generator helper.  It fixes annoying
     warning at the end of *note asyncio.run(): 47f. call.

   - bpo-38124(27): Fix an off-by-one error in PyState_AddModule that
     could cause out-of-bounds memory access.

   - bpo-38116(28): The select module is now PEP-384 compliant and no
     longer has static state

   - bpo-38113(29): ast module updated to PEP-384 and all statics
     removed

   - bpo-38076(30): The struct module is now PEP-384 compatible

   - bpo-38075(31): The random module is now PEP-384 compatible

   - bpo-38074(32): zlib module made PEP-384 compatible

   - bpo-38073(33): Make pwd extension module PEP-384 compatible

   - bpo-38072(34): grp module made PEP-384 compatible

   - bpo-38069(35): Make _posixsubprocess PEP-384 compatible

   - bpo-38071(36): Make termios extension module PEP-384 compatible

   - bpo-38005(37): Fixed comparing and creating of InterpreterID and
     ChannelID.

   - bpo-36946(38): Fix possible signed integer overflow when handling
     slices.  Patch by hongweipeng.

   - bpo-37994(39): Fixed silencing arbitrary errors if an attribute
     lookup fails in several sites.  Only AttributeError should be
     silenced.

   - bpo-8425(40): Optimize set difference_update for the case when the
     other set is much larger than the base set.  (Suggested by Evgeny
     Kapun with code contributed by Michele Orrù).

   - bpo-37966(41): The implementation of *note is_normalized(): a55.
     has been greatly sped up on strings that aren’t normalized, by
     implementing the full normalization-quick-check algorithm from the
     Unicode standard.

   - bpo-37947(42): Adjust correctly the recursion level in the symtable
     generation for named expressions.  Patch by Pablo Galindo.

   - bpo-37812(43): The ‘CHECK_SMALL_INT’ macro used inside
     ‘Object/longobject.c’ has been replaced with an explicit ‘return’
     at each call site.

   - bpo-37751(44): Fix *note codecs.lookup(): 96d. to normalize the
     encoding name the same way than *note
     encodings.normalize_encoding(): 801, except that ‘codecs.lookup()’
     also converts the name to lower case.

   - bpo-37830(45): Fixed compilation of *note break: abe. and *note
     continue: 9d4. in the *note finally: 9d5. block when the
     corresponding *note try: 6ec. block contains *note return: 9d9.
     with a non-constant value.

   - bpo-20490(46): Improve import error message for partially
     initialized module on circular ‘from’ imports - by Anthony Sottile.

   - bpo-37840(47): Fix handling of negative indices in *note sq_item:
     1a9c. of *note bytearray: 2ea.  Patch by Sergey Fedoseev.

   - bpo-37802(48): Slightly improve performance of *note
     PyLong_FromUnsignedLong(): 1b51, *note
     PyLong_FromUnsignedLongLong(): 1b52. and *note PyLong_FromSize_t():
     1b53.  Patch by Sergey Fedoseev.

   - bpo-37409(49): Ensure explicit relative imports from interactive
     sessions and scripts (having no parent package) always raise
     ImportError, rather than treating the current module as the
     package.  Patch by Ben Lewis.

   - bpo-32912(50): Reverted bpo-32912(51): emitting *note
     SyntaxWarning: 469. instead of *note DeprecationWarning: 1a5. for
     invalid escape sequences in string and bytes literals.

   - bpo-37757(52): PEP 572(53): As described in the PEP, assignment
     expressions now raise *note SyntaxError: 18d. when their
     interaction with comprehension scoping results in an ambiguous
     target scope.

     The ‘TargetScopeError’ subclass originally proposed by the PEP has
     been removed in favour of just raising regular syntax errors for
     the disallowed cases.

   - bpo-36279(54): Fix potential use of uninitialized memory in *note
     os.wait3(): dc4.

   - bpo-36311(55): Decoding bytes objects larger than 2GiB is faster
     and no longer fails when a multibyte characters spans a chunk
     boundary.

   - bpo-34880(56): The *note assert: 972. statement now works properly
     if the *note AssertionError: 6ac. exception is being shadowed.
     Patch by Zackery Spytz.

   - bpo-37340(57): Removed object cache (‘free_list’) for bound method
     objects.  Temporary bound method objects are less used than before
     thanks to the ‘LOAD_METHOD’ opcode and the
     ‘_PyObject_VectorcallMethod’ C API.

   - bpo-37648(58): Fixed minor inconsistency in ‘list.__contains__()’,
     ‘tuple.__contains__()’ and a few other places.  The collection’s
     item is now always at the left and the needle is on the right of
     ‘==’.

   - bpo-37444(59): Update differing exception between
     ‘builtins.__import__()’ and *note importlib.__import__(): 10ab.

   - bpo-37619(60): When adding a wrapper descriptor from one class to a
     different class (for example, setting ‘__add__ = str.__add__’ on an
     ‘int’ subclass), an exception is correctly raised when the operator
     is called.

   - bpo-37593(61): Swap the positions of the 'posonlyargs' and 'args'
     parameters in the constructor of ‘ast.parameters’ nodes.

   - bpo-37543(62): Optimized pymalloc for non PGO build.

   - bpo-37537(63): Compute allocated pymalloc blocks inside
     _Py_GetAllocatedBlocks().  This slows down _Py_GetAllocatedBlocks()
     but gives a small speedup to _PyObject_Malloc() and
     _PyObject_Free().

   - bpo-37467(64): Fix *note sys.excepthook(): 811. and
     ‘PyErr_Display()’ if a filename is a bytes string.  For example,
     for a SyntaxError exception where the filename attribute is a bytes
     string.

   - bpo-37433(65): Fix ‘SyntaxError’ indicator printing too many spaces
     for multi-line strings - by Anthony Sottile.

   - bpo-37417(66): *note bytearray.extend(): 15dc. now correctly
     handles errors that arise during iteration.  Patch by Brandt
     Bucher.

   - bpo-37414(67): The undocumented ‘sys.callstats()’ function has been
     removed.  Since Python 3.7, it was deprecated and always returned
     ‘None’.  It required a special build option ‘CALL_PROFILE’ which
     was already removed in Python 3.7.

   - bpo-37392(68): Remove ‘sys.getcheckinterval()’ and
     ‘sys.setcheckinterval()’ functions.  They were deprecated since
     Python 3.2.  Use *note sys.getswitchinterval(): 953. and *note
     sys.setswitchinterval(): 954. instead.  Remove also
     ‘check_interval’ field of the ‘PyInterpreterState’ structure.

   - bpo-37388(69): In development mode and in debug build, 'encoding'
     and 'errors' arguments are now checked on string encoding and
     decoding operations.  Examples: *note open(): 51f, *note
     str.encode(): 8de. and *note bytes.decode(): 8df.

     By default, for best performances, the 'errors' argument is only
     checked at the first encoding/decoding error, and the 'encoding'
     argument is sometimes ignored for empty strings.

   - bpo-37348(70): Optimized decoding short ASCII string with UTF-8 and
     ascii codecs.  ‘b"foo".decode()’ is about 15% faster.  Patch by
     Inada Naoki.

   - bpo-24214(71): Improved support of the surrogatepass error handler
     in the UTF-8 and UTF-16 incremental decoders.

   - bpo-37330(72): *note open(): 51f, *note io.open(): 520, *note
     codecs.open(): 743. and *note fileinput.FileInput: 73a. no longer
     accept ‘'U'’ (“universal newline”) in the file mode.  This flag was
     deprecated since Python 3.3.

   - bpo-35224(73): Reverse evaluation order of key: value in dict
     comprehensions as proposed in PEP 572.  I.e.  in ‘{k: v for ...}’,
     ‘k’ will be evaluated before ‘v’.

   - bpo-37316(74): Fix the *note PySys_Audit(): 372. call in *note
     mmap.mmap: 20b.

   - bpo-37300(75): Remove an unnecessary Py_XINCREF in classobject.c.

   - bpo-37269(76): Fix a bug in the peephole optimizer that was not
     treating correctly constant conditions with binary operators.
     Patch by Pablo Galindo.

   - bpo-20443(77): Python now gets the absolute path of the script
     filename specified on the command line (ex: “python3 script.py”):
     the __file__ attribute of the __main__ module and sys.path[0]
     become an absolute path, rather than a relative path.

   - bpo-37257(78): Python’s small object allocator (‘obmalloc.c’) now
     allows (no more than) one empty arena to remain available for
     immediate reuse, without returning it to the OS. This prevents
     thrashing in simple loops where an arena could be created and
     destroyed anew on each iteration.

   - bpo-37231(79): The dispatching of type slots to special methods
     (for example calling ‘__mul__’ when doing ‘x * y’) has been made
     faster.

   - bpo-36974(80): Implemented separate vectorcall functions for every
     calling convention of builtin functions and methods.  This improves
     performance for calls.

   - bpo-37213(81): Handle correctly negative line offsets in the
     peephole optimizer.  Patch by Pablo Galindo.

   - bpo-37219(82): Remove erroneous optimization for empty set
     differences.

   - bpo-15913(83): Implement *note PyBuffer_SizeFromFormat(): 75d.
     function (previously documented but not implemented): call *note
     struct.calcsize(): 1b54.  Patch by Joannah Nanjekye.

   - bpo-36922(84): Slot functions optimize any callable with
     ‘Py_TPFLAGS_METHOD_DESCRIPTOR’ instead of only instances of
     ‘function’.

   - bpo-36974(85): The slot ‘tp_vectorcall_offset’ is inherited
     unconditionally to support ‘super().__call__()’ when the base class
     uses vectorcall.

   - bpo-37160(86): *note threading.get_native_id(): a4b. now also
     supports NetBSD.

   - bpo-37077(87): Add *note threading.get_native_id(): a4b. support
     for AIX. Patch by M. Felt

   - bpo-36781(88): *note sum(): 46d. has been optimized for boolean
     values.

   - bpo-34556(89): Add ‘--upgrade-deps’ to venv module.  Patch by
     Cooper Ry Lees

   - bpo-20523(90): ‘pdb.Pdb’ supports ~/.pdbrc in Windows 7.  Patch by
     Tim Hopper and Dan Lidral-Porter.

   - bpo-35551(91): Updated encodings: - Removed the “tis260” encoding,
     which was an alias for the nonexistent “tactis” codec.  - Added
     “mac_centeuro” as an alias for the mac_latin2 encoding.

   - bpo-19072(92): The *note classmethod: 166. decorator can now wrap
     other descriptors such as property objects.  Adapted from a patch
     written by Graham Dumpleton.

   - bpo-27575(93): Improve speed of dictview intersection by directly
     using set intersection logic.  Patch by David Su.

   - bpo-30773(94): Prohibit parallel running of aclose() / asend() /
     athrow().  Fix ag_running to reflect the actual running status of
     the AG.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38631

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38639

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38640

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38613

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28029

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38535

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38525

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38465

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38469

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38437

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38379

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38379

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38392

   (14) https://bugs.python.org/issue?@action=redirect&bpo=38210

   (15) https://bugs.python.org/issue?@action=redirect&bpo=38210

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38402

   (17) https://bugs.python.org/issue?@action=redirect&bpo=37474

   (18) https://bugs.python.org/issue?@action=redirect&bpo=38006

   (19) https://bugs.python.org/issue?@action=redirect&bpo=38317

   (20) https://peps.python.org/pep-0587/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=38310

   (22) https://bugs.python.org/issue?@action=redirect&bpo=36871

   (23) https://bugs.python.org/issue?@action=redirect&bpo=11410

   (24) https://bugs.python.org/issue?@action=redirect&bpo=38219

   (25) https://bugs.python.org/issue?@action=redirect&bpo=38236

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38013

   (27) https://bugs.python.org/issue?@action=redirect&bpo=38124

   (28) https://bugs.python.org/issue?@action=redirect&bpo=38116

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38113

   (30) https://bugs.python.org/issue?@action=redirect&bpo=38076

   (31) https://bugs.python.org/issue?@action=redirect&bpo=38075

   (32) https://bugs.python.org/issue?@action=redirect&bpo=38074

   (33) https://bugs.python.org/issue?@action=redirect&bpo=38073

   (34) https://bugs.python.org/issue?@action=redirect&bpo=38072

   (35) https://bugs.python.org/issue?@action=redirect&bpo=38069

   (36) https://bugs.python.org/issue?@action=redirect&bpo=38071

   (37) https://bugs.python.org/issue?@action=redirect&bpo=38005

   (38) https://bugs.python.org/issue?@action=redirect&bpo=36946

   (39) https://bugs.python.org/issue?@action=redirect&bpo=37994

   (40) https://bugs.python.org/issue?@action=redirect&bpo=8425

   (41) https://bugs.python.org/issue?@action=redirect&bpo=37966

   (42) https://bugs.python.org/issue?@action=redirect&bpo=37947

   (43) https://bugs.python.org/issue?@action=redirect&bpo=37812

   (44) https://bugs.python.org/issue?@action=redirect&bpo=37751

   (45) https://bugs.python.org/issue?@action=redirect&bpo=37830

   (46) https://bugs.python.org/issue?@action=redirect&bpo=20490

   (47) https://bugs.python.org/issue?@action=redirect&bpo=37840

   (48) https://bugs.python.org/issue?@action=redirect&bpo=37802

   (49) https://bugs.python.org/issue?@action=redirect&bpo=37409

   (50) https://bugs.python.org/issue?@action=redirect&bpo=32912

   (51) https://bugs.python.org/issue?@action=redirect&bpo=32912

   (52) https://bugs.python.org/issue?@action=redirect&bpo=37757

   (53) https://peps.python.org/pep-0572/

   (54) https://bugs.python.org/issue?@action=redirect&bpo=36279

   (55) https://bugs.python.org/issue?@action=redirect&bpo=36311

   (56) https://bugs.python.org/issue?@action=redirect&bpo=34880

   (57) https://bugs.python.org/issue?@action=redirect&bpo=37340

   (58) https://bugs.python.org/issue?@action=redirect&bpo=37648

   (59) https://bugs.python.org/issue?@action=redirect&bpo=37444

   (60) https://bugs.python.org/issue?@action=redirect&bpo=37619

   (61) https://bugs.python.org/issue?@action=redirect&bpo=37593

   (62) https://bugs.python.org/issue?@action=redirect&bpo=37543

   (63) https://bugs.python.org/issue?@action=redirect&bpo=37537

   (64) https://bugs.python.org/issue?@action=redirect&bpo=37467

   (65) https://bugs.python.org/issue?@action=redirect&bpo=37433

   (66) https://bugs.python.org/issue?@action=redirect&bpo=37417

   (67) https://bugs.python.org/issue?@action=redirect&bpo=37414

   (68) https://bugs.python.org/issue?@action=redirect&bpo=37392

   (69) https://bugs.python.org/issue?@action=redirect&bpo=37388

   (70) https://bugs.python.org/issue?@action=redirect&bpo=37348

   (71) https://bugs.python.org/issue?@action=redirect&bpo=24214

   (72) https://bugs.python.org/issue?@action=redirect&bpo=37330

   (73) https://bugs.python.org/issue?@action=redirect&bpo=35224

   (74) https://bugs.python.org/issue?@action=redirect&bpo=37316

   (75) https://bugs.python.org/issue?@action=redirect&bpo=37300

   (76) https://bugs.python.org/issue?@action=redirect&bpo=37269

   (77) https://bugs.python.org/issue?@action=redirect&bpo=20443

   (78) https://bugs.python.org/issue?@action=redirect&bpo=37257

   (79) https://bugs.python.org/issue?@action=redirect&bpo=37231

   (80) https://bugs.python.org/issue?@action=redirect&bpo=36974

   (81) https://bugs.python.org/issue?@action=redirect&bpo=37213

   (82) https://bugs.python.org/issue?@action=redirect&bpo=37219

   (83) https://bugs.python.org/issue?@action=redirect&bpo=15913

   (84) https://bugs.python.org/issue?@action=redirect&bpo=36922

   (85) https://bugs.python.org/issue?@action=redirect&bpo=36974

   (86) https://bugs.python.org/issue?@action=redirect&bpo=37160

   (87) https://bugs.python.org/issue?@action=redirect&bpo=37077

   (88) https://bugs.python.org/issue?@action=redirect&bpo=36781

   (89) https://bugs.python.org/issue?@action=redirect&bpo=34556

   (90) https://bugs.python.org/issue?@action=redirect&bpo=20523

   (91) https://bugs.python.org/issue?@action=redirect&bpo=35551

   (92) https://bugs.python.org/issue?@action=redirect&bpo=19072

   (93) https://bugs.python.org/issue?@action=redirect&bpo=27575

   (94) https://bugs.python.org/issue?@action=redirect&bpo=30773


File: python.info,  Node: Library<133>,  Next: Documentation<49>,  Prev: Core and Builtins<131>,  Up: Python 3 9 0 alpha 1

1.23.58.3 Library
.................

   - bpo-36589(1): The *note curses.update_lines_cols(): e1c. function
     now returns ‘None’ instead of ‘1’ on success.

   - bpo-38807(2): Update *note TypeError: 2c3. messages for *note
     os.path.join(): 173c. to include *note os.PathLike: c72. objects as
     acceptable input types.

   - bpo-38724(3): Add a repr for ‘subprocess.Popen’ objects.  Patch by
     Andrey Doroschenko.

   - bpo-38786(4): pydoc now recognizes and parses HTTPS URLs.  Patch by
     python273.

   - bpo-38785(5): Prevent asyncio from crashing if parent ‘__init__’ is
     not called from a constructor of object derived from
     ‘asyncio.Future’.

   - bpo-38723(6): *note pdb: a5. now uses *note io.open_code(): 15a7.
     to trigger auditing events.

   - bpo-27805(7): Allow opening pipes and other non-seekable files in
     append mode with *note open(): 51f.

   - bpo-38438(8): Simplify the *note argparse: 6. usage message for
     ‘nargs="*"’.

   - bpo-38761(9): WeakSet is now registered as a
     collections.abc.MutableSet.

   - bpo-38716(10): logging: change RotatingHandler namer and rotator to
     class-level attributes.  This stops __init__ from setting them to
     None in the case where a subclass defines them with eponymous
     methods.

   - bpo-38713(11): Add *note os.P_PIDFD: 923. constant, which may be
     passed to *note os.waitid(): dc7. to wait on a Linux process file
     descriptor.

   - bpo-38692(12): Add *note asyncio.PidfdChildWatcher: 47c, a
     Linux-specific child watcher implementation that polls process file
     descriptors.

   - bpo-38692(13): Expose the Linux ‘pidfd_open’ syscall as *note
     os.pidfd_open(): 47d.

   - bpo-38602(14): Added constants ‘F_OFD_GETLK’, ‘F_OFD_SETLK’ and
     ‘F_OFD_SETLKW’ to the *note fcntl: 59. module.  Patch by Donghee
     Na.

   - bpo-38334(15): Fixed seeking backward on an encrypted
     ‘zipfile.ZipExtFile’.

   - bpo-38312(16): Add *note curses.get_escdelay(): 8f9, *note
     curses.set_escdelay(): 8fa, *note curses.get_tabsize(): 8fb, and
     *note curses.set_tabsize(): 8fc. functions - by Anthony Sottile.

   - bpo-38586(17): Now *note fileConfig(): b6c. correctly sets the
     .name of handlers loaded.

   - bpo-38565(18): Add new cache_parameters() method for
     functools.lru_cache() to better support pickling.

   - bpo-34679(19): asynci.ProactorEventLoop.close() now only calls
     signal.set_wakeup_fd() in the main thread.

   - bpo-31202(20): The case the result of ‘pathlib.WindowsPath.glob()’
     matches now the case of the pattern for literal parts.

   - bpo-36321(21): Remove misspelled attribute.  The 3.8 changelog
     noted that this would be removed in 3.9.

   - bpo-38521(22): Fixed erroneous equality comparison in
     statistics.NormalDist().

   - bpo-38493(23): Added *note CLD_KILLED: 921. and *note CLD_STOPPED:
     922. for ‘si_code’.  Patch by Donghee Na.

   - bpo-38478(24): Fixed a bug in ‘inspect.signature.bind()’ that was
     causing it to fail when handling a keyword argument with same name
     as positional-only parameter.  Patch by Pablo Galindo.

   - bpo-33604(25): Fixed ‘hmac.new’ and ‘hmac.HMAC’ to raise TypeError
     instead of ValueError when the digestmod parameter, now required in
     3.8, is omitted.  Also clarified the hmac module documentation and
     docstrings.

   - bpo-38378(26): Parameters 'out' and 'in' of *note os.sendfile():
     b28. was renamed to 'out_fd' and 'in_fd'.

   - bpo-38417(27): Added support for setting the umask in the child
     process to the subprocess module on POSIX systems.

   - bpo-38449(28): Revert PR 15522, which introduces a regression in
     *note mimetypes.guess_type(): 208. due to improper handling of
     filenames as urls.

   - bpo-38431(29): Fix ‘__repr__’ method for *note dataclasses.InitVar:
     1959. to support typing objects, patch by Samuel Colvin.

   - bpo-38109(30): Add missing *note stat.S_IFDOOR: ff4, *note
     stat.S_IFPORT: ff5, *note stat.S_IFWHT: ff6, *note stat.S_ISDOOR():
     1b56, *note stat.S_ISPORT(): 1b57, and *note stat.S_ISWHT(): 1b58.
     values to the Python implementation of *note stat: d1.

   - bpo-38422(31): Clarify docstrings of pathlib suffix(es)

   - bpo-38405(32): Nested subclasses of *note typing.NamedTuple: 2b0.
     are now pickleable.

   - bpo-38332(33): Prevent *note KeyError: 345. thrown by
     ‘_encoded_words.decode()’ when given an encoded-word with invalid
     content-type encoding from propagating all the way to
     ‘email.message.get()’.

   - bpo-38371(34): Deprecated the ‘split()’ method in
     ‘_tkinter.TkappType’ in favour of the ‘splitlist()’ method which
     has more consistent and predictable behavior.

   - bpo-38341(35): Add *note smtplib.SMTPNotSupportedError: 1b59. to
     the *note smtplib: ca. exported names.

   - bpo-38319(36): sendfile() used in socket and shutil modules was
     raising OverflowError for files >= 2GiB on 32-bit architectures.
     (patch by Giampaolo Rodola)

   - bpo-38242(37): Revert the new asyncio Streams API

   - bpo-13153(38): OS native encoding is now used for converting
     between Python strings and Tcl objects.  This allows to display,
     copy and paste to clipboard emoji and other non-BMP characters.
     Converting strings from Tcl to Python and back now never fails
     (except MemoryError).

   - bpo-38019(39): Correctly handle pause/resume reading of closed
     asyncio unix pipe.

   - bpo-38163(40): Child mocks will now detect their type as either
     synchronous or asynchronous, asynchronous child mocks will be
     AsyncMocks and synchronous child mocks will be either MagicMock or
     Mock (depending on their parent type).

   - bpo-38161(41): Removes _AwaitEvent from AsyncMock.

   - bpo-38216(42): Allow the rare code that wants to send invalid http
     requests from the ‘http.client’ library a way to do so.  The fixes
     for bpo-30458(43) led to breakage for some projects that were
     relying on this ability to test their own behavior in the face of
     bad requests.

   - bpo-28286(44): Deprecate opening *note GzipFile: 41d. for writing
     implicitly.  Always specify the 'mode' argument for writing.

   - bpo-38108(45): Any synchronous magic methods on an AsyncMock now
     return a MagicMock.  Any asynchronous magic methods on a MagicMock
     now return an AsyncMock.

   - bpo-38265(46): Update the 'length' parameter of *note os.pread():
     b7b. to accept *note Py_ssize_t: a6e. instead of int.

   - bpo-38112(47): *note compileall: 20. has a higher default recursion
     limit and new command-line arguments for path manipulation,
     symlinks handling, and multiple optimization levels.

   - bpo-38248(48): asyncio: Fix inconsistent immediate Task
     cancellation

   - bpo-38237(49): The arguments for the builtin pow function are more
     descriptive.  They can now also be passed in as keywords.

   - bpo-34002(50): Improve efficiency in parts of email package by
     changing while-pop to a for loop, using isdisjoint instead of set
     intersections.

   - bpo-38191(51): Constructors of *note NamedTuple: 2b0. and *note
     TypedDict: 162. types now accept arbitrary keyword argument names,
     including “cls”, “self”, “typename”, “_typename”, “fields” and
     “_fields”.

   - bpo-38155(52): Add ‘__all__’ to *note datetime: 30.  Patch by Tahia
     Khan.

   - bpo-38185(53): Fixed case-insensitive string comparison in *note
     sqlite3.Row: ea5. indexing.

   - bpo-38136(54): Changes AsyncMock call count and await count to be
     two different counters.  Now await count only counts when a
     coroutine has been awaited, not when it has been called, and
     vice-versa.  Update the documentation around this.

   - bpo-37828(55): Fix default mock name in *note
     unittest.mock.Mock.assert_called(): d1f. exceptions.  Patch by
     Abraham Toriz Cruz.

   - bpo-38175(56): Fix a memory leak in comparison of *note
     sqlite3.Row: ea5. objects.

   - bpo-33936(57): _hashlib no longer calls obsolete OpenSSL
     initialization function with OpenSSL 1.1.0+.

   - bpo-34706(58): Preserve subclassing in
     inspect.Signature.from_callable.

   - bpo-38153(59): Names of hashing algorithms from OpenSSL are now
     normalized to follow Python’s naming conventions.  For example
     OpenSSL uses sha3-512 instead of sha3_512 or blake2b512 instead of
     blake2b.

   - bpo-38115(60): Fix a bug in dis.findlinestarts() where it would
     return invalid bytecode offsets.  Document that a code object’s
     co_lnotab can contain invalid bytecode offsets.

   - bpo-38148(61): Add slots to *note asyncio: a. transport classes,
     which can reduce memory usage.

   - bpo-38142(62): The _hashlib OpenSSL wrapper extension module is now
     PEP-384 compliant.

   - bpo-9216(63): hashlib constructors now support usedforsecurity flag
     to signal that a hashing algorithm is not used in a security
     context.

   - bpo-36991(64): Fixes a potential incorrect AttributeError exception
     escaping ZipFile.extract() in some unsupported input error
     situations.

   - bpo-38134(65): Remove obsolete copy of PBKDF2_HMAC_fast.  All
     supported OpenSSL versions contain a fast implementation.

   - bpo-38132(66): The OpenSSL hashlib wrapper uses a simpler
     implementation.  Several Macros and pointless caches are gone.  The
     hash name now comes from OpenSSL’s EVP. The algorithm name stays
     the same, except it is now always lower case.

   - bpo-38008(67): Fix parent class check in protocols to correctly
     identify the module that provides a builtin protocol, instead of
     assuming they all come from the *note collections.abc: 1e. module

   - bpo-34037(68): For *note asyncio: a, add a new coroutine
     ‘loop.shutdown_default_executor()’.  The new coroutine provides an
     API to schedule an executor shutdown that waits on the threadpool
     to finish closing.  Also, *note asyncio.run(): 47f. has been
     updated to utilize the new coroutine.  Patch by Kyle Stanley.

   - bpo-37405(69): Fixed regression bug for socket.getsockname() for
     non-CAN_ISOTP AF_CAN address family sockets by returning a 1-tuple
     instead of string.

   - bpo-38121(70): Update parameter names on functions in
     importlib.metadata matching the changes in the 0.22 release of
     importlib_metadata.

   - bpo-38110(71): The os.closewalk() implementation now uses the libc
     fdwalk() API on platforms where it is available.

   - bpo-38093(72): Fixes AsyncMock so it doesn’t crash when used with
     AsyncContextManagers or AsyncIterators.

   - bpo-37488(73): Add warning to ‘datetime.utctimetuple()’,
     ‘datetime.utcnow()’ and ‘datetime.utcfromtimestamp()’ .

   - bpo-35640(74): Allow passing a *note path-like object: 2a0. as
     ‘directory’ argument to the *note
     http.server.SimpleHTTPRequestHandler: b5c. class.  Patch by Géry
     Ogam.

   - bpo-38086(75): Update importlib.metadata with changes from
     importlib_metadata 0.21(76).

   - bpo-37251(77): Remove ‘__code__’ check in AsyncMock that
     incorrectly evaluated function specs as async objects but failed to
     evaluate classes with ‘__await__’ but no ‘__code__’ attribute
     defined as async objects.

   - bpo-38037(78): Fix reference counters in the *note signal: c6.
     module.

   - bpo-38066(79): Hide internal asyncio.Stream methods: feed_eof(),
     feed_data(), set_exception() and set_transport().

   - bpo-38059(80): inspect.py now uses sys.exit() instead of exit()

   - bpo-38049(81): Added command-line interface for the *note ast: 8.
     module.

   - bpo-37953(82): In *note typing: 104, improved the ‘__hash__’ and
     ‘__eq__’ methods for ‘ForwardReferences’.

   - bpo-38026(83): Fixed *note inspect.getattr_static(): 497. used
     ‘isinstance’ while it should avoid dynamic lookup.

   - bpo-35923(84): Update *note importlib.machinery.BuiltinImporter:
     cd5. to use ‘loader._ORIGIN’ instead of a hardcoded value.  Patch
     by Donghee Na.

   - bpo-38010(85): In ‘importlib.metadata’ sync with
     ‘importlib_metadata’ 0.20, clarifying behavior of ‘files()’ and
     fixing issue where only one requirement was returned for
     ‘requires()’ on ‘dist-info’ packages.

   - bpo-38006(86): weakref.WeakValueDictionary defines a local remove()
     function used as callback for weak references.  This function was
     created with a closure.  Modify the implementation to avoid the
     closure.

   - bpo-37995(87): Added the 'indent' option to *note ast.dump(): 8ed.
     which allows it to produce a multiline indented output.

   - bpo-34410(88): Fixed a crash in the ‘tee()’ iterator when re-enter
     it.  RuntimeError is now raised in this case.

   - bpo-37140(89): Fix a ctypes regression of Python 3.8.  When a
     ctypes.Structure is passed by copy to a function, ctypes internals
     created a temporary object which had the side effect of calling the
     structure finalizer (__del__) twice.  The Python semantics requires
     a finalizer to be called exactly once.  Fix ctypes internals to no
     longer call the finalizer twice.

   - bpo-37587(90): ‘_json.scanstring’ is now up to 3x faster when there
     are many backslash escaped characters in the JSON string.

   - bpo-37834(91): Prevent shutil.rmtree exception when built on
     non-Windows system without fd system call support, like older
     versions of macOS.

   - bpo-10978(92): Semaphores and BoundedSemaphores can now release
     more than one waiting thread at a time.

   - bpo-37972(93): Subscripts to the ‘unittest.mock.call’ objects now
     receive the same chaining mechanism as any other custom attributes,
     so that the following usage no longer raises a ‘TypeError’:

     ‘call().foo().__getitem__('bar')’

     Patch by blhsing

   - bpo-37965(94): Fix C compiler warning caused by
     distutils.ccompiler.CCompiler.has_function.

   - bpo-37964(95): Add ‘F_GETPATH’ command to *note fcntl: 59.

   - bpo-37960(96): ‘repr()’ of buffered and text streams now silences
     only expected exceptions when get the value of “name” and “mode”
     attributes.

   - bpo-37961(97): Add a ‘total_nframe’ field to the traces collected
     by the tracemalloc module.  This field indicates the original
     number of frames before it was truncated.

   - bpo-37951(98): Most features of the subprocess module now work
     again in subinterpreters.  Only 'preexec_fn' is restricted in
     subinterpreters.

   - bpo-36205(99): Fix the rusage implementation of time.process_time()
     to correctly report the sum of the system and user CPU time.

   - bpo-37950(100): Fix *note ast.dump(): 8ed. when call with
     incompletely initialized node.

   - bpo-34679(101): Restores instantiation of Windows IOCP event loops
     from the non-main thread.

   - bpo-36917(102): Add default implementation of the *note
     ast.NodeVisitor.visit_Constant(): a7d. method which emits a
     deprecation warning and calls corresponding methods ‘visit_Num()’,
     ‘visit_Str()’, etc.

   - bpo-37798(103): Update test_statistics.py to verify that the
     statistics module works well for both C and Python implementations.
     Patch by Donghee Na

   - bpo-26589(104): Added a new status code to the http module: 451
     UNAVAILABLE_FOR_LEGAL_REASONS

   - bpo-37915(105): Fix a segmentation fault that appeared when
     comparing instances of ‘datetime.timezone’ and ‘datetime.tzinfo’
     objects.  Patch by Pablo Galindo.

   - bpo-32554(106): Deprecate having random.seed() call hash on
     arbitrary types.

   - bpo-9938(107): Add optional keyword argument ‘exit_on_error’ for
     ‘ArgumentParser’.

   - bpo-37851(108): The *note faulthandler: 58. module no longer
     allocates its alternative stack at Python startup.  Now the stack
     is only allocated at the first faulthandler usage.

   - bpo-32793(109): Fix a duplicated debug message when *note
     smtplib.SMTP.connect(): 1b5a. is called.

   - bpo-37885(110): venv: Don’t generate unset variable warning on
     deactivate.

   - bpo-37868(111): Fix dataclasses.is_dataclass when given an instance
     that never raises AttributeError in __getattr__.  That is, an
     object that returns something for __dataclass_fields__ even if it’s
     not a dataclass.

   - bpo-37811(112): Fix ‘socket’ module’s ‘socket.connect(address)’
     function being unable to establish connection in case of
     interrupted system call.  The problem was observed on all OSes
     which ‘poll(2)’ system call can take only non-negative integers and
     -1 as a timeout value.

   - bpo-37863(113): Optimizations for Fraction.__hash__ suggested by
     Tim Peters.

   - bpo-21131(114): Fix ‘faulthandler.register(chain=True)’ stack.
     faulthandler now allocates a dedicated stack of ‘SIGSTKSZ*2’ bytes,
     instead of just ‘SIGSTKSZ’ bytes.  Calling the previous signal
     handler in faulthandler signal handler uses more than ‘SIGSTKSZ’
     bytes of stack memory on some platforms.

   - bpo-37798(115): Add C fastpath for statistics.NormalDist.inv_cdf()
     Patch by Donghee Na

   - bpo-37804(116): Remove the deprecated method
     ‘threading.Thread.isAlive()’.  Patch by Donghee Na.

   - bpo-37819(117): Add Fraction.as_integer_ratio() to match the
     corresponding methods in bool, int, float, and decimal.

   - bpo-14465(118): Add an xml.etree.ElementTree.indent() function for
     pretty-printing XML trees.  Contributed by Stefan Behnel.

   - bpo-37810(119): Fix *note difflib: 37. ‘?’ hint in diff output when
     dealing with tabs.  Patch by Anthony Sottile.

   - bpo-37772(120): In ‘zipfile.Path’, when adding implicit dirs,
     ensure that ancestral directories are added and that duplicates are
     excluded.

   - bpo-18578(121): Renamed and documented ‘test.bytecode_helper’ as
     ‘test.support.bytecode_helper’.  Patch by Joannah Nanjekye.

   - bpo-37785(122): Fix xgettext warnings in *note argparse: 6.

   - bpo-34488(123): ‘writelines()’ method of *note io.BytesIO: ed8. is
     now slightly faster when many small lines are passed.  Patch by
     Sergey Fedoseev.

   - bpo-37449(124): ‘ensurepip’ now uses
     ‘importlib.resources.read_binary()’ to read data instead of
     ‘pkgutil.get_data()’.  Patch by Joannah Nanjekye.

   - bpo-28292(125): Mark calendar.py helper functions as being private.
     The follows PEP 8 guidance to maintain the style conventions in the
     module and it addresses a known case of user confusion.

   - bpo-18049(126): Add definition of THREAD_STACK_SIZE for AIX in
     Python/thread_pthread.h The default thread stacksize caused crashes
     with the default recursion limit Patch by M Felt

   - bpo-37742(127): The logging.getLogger() API now returns the root
     logger when passed the name ‘root’, whereas previously it returned
     a non-root logger named ‘root’.  This could affect cases where user
     code explicitly wants a non-root logger named ‘root’, or
     instantiates a logger using logging.getLogger(__name__) in some
     top-level module called ‘root.py’.

   - bpo-37738(128): Fix the implementation of curses ‘addch(str,
     color_pair)’: pass the color pair to ‘setcchar()’, instead of
     always passing 0 as the color pair.

   - bpo-37723(129): Fix performance regression on regular expression
     parsing with huge character sets.  Patch by Yann Vaginay.

   - bpo-35943(130): The function *note PyImport_GetModule(): bd1. now
     ensures any module it returns is fully initialized.  Patch by
     Joannah Nanjekye.

   - bpo-32178(131): Fix IndexError in *note email: 3b. package when
     trying to parse invalid address fields starting with ‘:’.

   - bpo-37268(132): The ‘parser’ module is deprecated and will be
     removed in future versions of Python.

   - bpo-11953(133): Completing WSA* error codes in *note socket: cc.

   - bpo-37685(134): Fixed comparisons of *note datetime.timedelta: 9da.
     and *note datetime.timezone: 1103.

   - bpo-37697(135): Synchronize ‘importlib.metadata’ with
     importlib_metadata 0.19(136), improving handling of EGG-INFO files
     and fixing a crash when entry point names contained colons.

   - bpo-37695(137): Correct *note curses.unget_wch(): 10dc. error
     message.  Patch by Anthony Sottile.

   - bpo-37689(138): Add ‘is_relative_to()’ in ‘PurePath’ to determine
     whether or not one path is relative to another.

   - bpo-29553(139): Fixed *note argparse.ArgumentParser.format_usage():
     1b5b. for mutually exclusive groups.  Patch by Andrew Nester.

   - bpo-37691(140): Let math.dist() accept coordinates as sequences (or
     iterables) rather than just tuples.

   - bpo-37685(141): Fixed ‘__eq__’, ‘__lt__’ etc implementations in
     some classes.  They now return *note NotImplemented: 7d6. for
     unsupported type of the other operand.  This allows the other
     operand to play role (for example the equality comparison with
     *note ANY: 1b5c. will return ‘True’).

   - bpo-37354(142): Make Activate.ps1 Powershell script static to allow
     for signing it.

   - bpo-37664(143): Update wheels bundled with ensurepip (pip 19.2.3
     and setuptools 41.2.0)

   - bpo-37663(144): Bring consistency to venv shell activation scripts
     by always using __VENV_PROMPT__.

   - bpo-37642(145): Allowed the pure Python implementation of *note
     datetime.timezone: 1103. to represent sub-minute offsets close to
     minimum and maximum boundaries, specifically in the ranges (23:59,
     24:00) and (-23:59, 24:00).  Patch by Ngalim Siregar

   - bpo-36161(146): In *note posix: ad, use ‘ttyname_r’ instead of
     ‘ttyname’ for thread safety.

   - bpo-36324(147): Make internal attributes for
     statistics.NormalDist() private.

   - bpo-37555(148): Fix ‘NonCallableMock._call_matcher’ returning tuple
     instead of ‘_Call’ object when ‘self._spec_signature’ exists.
     Patch by Elizabeth Uselton

   - bpo-29446(149): Make ‘from tkinter import *’ import only the
     expected objects.

   - bpo-16970(150): Adding a value error when an invalid value in
     passed to nargs Patch by Robert Leenders

   - bpo-34443(151): Exceptions from *note enum: 56. now use the
     ‘__qualname’ of the enum class in the exception message instead of
     the ‘__name__’.

   - bpo-37491(152): Fix ‘IndexError’ when parsing email headers with
     unexpectedly ending bare-quoted string value.  Patch by Abhilash
     Raj.

   - bpo-37587(153): Make json.loads faster for long strings.  (Patch by
     Marco Paolini)

   - bpo-18378(154): Recognize “UTF-8” as a valid value for LC_CTYPE in
     locale._parse_localename.

   - bpo-37579(155): Return *note NotImplemented: 7d6. in Python
     implementation of ‘__eq__’ for *note timedelta: 9da. and *note
     time: 1ce. when the other object being compared is not of the same
     type to match C implementation.  Patch by Karthikeyan Singaravelan.

   - bpo-21478(156): Record calls to parent when autospecced object is
     attached to a mock using ‘unittest.mock.attach_mock()’.  Patch by
     Karthikeyan Singaravelan.

   - bpo-37531(157): “python3 -m test -jN –timeout=TIMEOUT” now kills a
     worker process if it runs longer than 'TIMEOUT' seconds.

   - bpo-37482(158): Fix serialization of display name in originator or
     destination address fields with both encoded words and special
     chars.

   - bpo-36993(159): Improve error reporting for corrupt zip files with
     bad zip64 extra data.  Patch by Daniel Hillier.

   - bpo-37502(160): pickle.loads() no longer raises TypeError when the
     buffers argument is set to None

   - bpo-37520(161): Correct behavior for zipfile.Path.parent when the
     path object identifies a subdirectory.

   - bpo-18374(162): Fix the ‘.col_offset’ attribute of nested *note
     ast.BinOp: 1b5d. instances which had a too large value in some
     situations.

   - bpo-37424(163): Fixes a possible hang when using a timeout on
     ‘subprocess.run()’ while capturing output.  If the child process
     spawned its own children or otherwise connected its stdout or
     stderr handles with another process, we could hang after the
     timeout was reached and our child was killed when attempting to
     read final output from the pipes.

   - bpo-37421(164): Fix ‘multiprocessing.util.get_temp_dir()’
     finalizer: clear also the ‘tempdir’ configuration of the current
     process, so next call to ‘get_temp_dir()’ will create a new
     temporary directory, rather than reusing the removed temporary
     directory.

   - bpo-37481(165): The distutils ‘bdist_wininst’ command is deprecated
     in Python 3.8, use ‘bdist_wheel’ (wheel packages) instead.

   - bpo-37479(166): When ‘Enum.__str__’ is overridden in a derived
     class, the override will be used by ‘Enum.__format__’ regardless of
     whether mixin classes are present.

   - bpo-37440(167): http.client now enables TLS 1.3 post-handshake
     authentication for default context or if a cert_file is passed to
     HTTPSConnection.

   - bpo-37437(168): Update vendorized expat version to 2.2.7.

   - bpo-37428(169): SSLContext.post_handshake_auth = True no longer
     sets SSL_VERIFY_POST_HANDSHAKE verify flag for client connections.
     Although the option is documented as ignored for clients, OpenSSL
     implicitly enables cert chain validation when the flag is set.

   - bpo-37420(170): *note os.sched_setaffinity(): 1152. now correctly
     handles errors that arise during iteration over its ‘mask’
     argument.  Patch by Brandt Bucher.

   - bpo-37412(171): The *note os.getcwdb(): aa0. function now uses the
     UTF-8 encoding on Windows, rather than the ANSI code page: see PEP
     529(172) for the rationale.  The function is no longer deprecated
     on Windows.

   - bpo-37406(173): The sqlite3 module now raises TypeError, rather
     than ValueError, if operation argument type is not str: execute(),
     executemany() and calling a connection.

   - bpo-29412(174): Fix IndexError in parsing a header value ending
     unexpectedly.  Patch by Abhilash Raj.

   - bpo-36546(175): The 'dist' argument for statistics.quantiles() is
     now positional only.  The current name doesn’t reflect that the
     argument can be either a dataset or a distribution.  Marking the
     parameter as positional avoids confusion and makes it possible to
     change the name later.

   - bpo-37394(176): Fix a bug that was causing the *note queue: b6.
     module to fail if the accelerator module was not available.  Patch
     by Pablo Galindo.

   - bpo-37376(177): *note pprint: ae. now has support for *note
     types.SimpleNamespace: 1d1.  Patch by Carl Bordum Hansen.

   - bpo-26967(178): An *note ArgumentParser: 53c. with
     ‘allow_abbrev=False’ no longer disables grouping of short flags,
     such as ‘-vv’, but only disables abbreviation of long flags as
     documented.  Patch by Zac Hatfield-Dodds.

   - bpo-37212(179): *note unittest.mock.call(): 1b5e. now preserves the
     order of keyword arguments in repr output.  Patch by Karthikeyan
     Singaravelan.

   - bpo-37372(180): Fix error unpickling datetime.time objects from
     Python 2 with seconds>=24.  Patch by Justin Blanchard.

   - bpo-37345(181): Add formal support for UDPLITE sockets.  Support
     was present before, but it is now easier to detect support with
     ‘hasattr(socket, 'IPPROTO_UDPLITE')’ and there are constants
     defined for each of the values needed: ‘socket.IPPROTO_UDPLITE’,
     ‘UDPLITE_SEND_CSCOV’, and ‘UDPLITE_RECV_CSCOV’.  Patch by Gabe
     Appleton.

   - bpo-37358(182): Optimized ‘functools.partial’ by using vectorcall.

   - bpo-37347(183): *note sqlite3.Connection.create_aggregate(): 2aa,
     *note sqlite3.Connection.create_function(): 2a9, *note
     sqlite3.Connection.set_authorizer(): 2ab, *note
     sqlite3.Connection.set_progress_handler(): 2ac. *note
     sqlite3.Connection.set_trace_callback(): 2ad. methods lead to
     segfaults if some of these methods are called twice with an equal
     object but not the same.  Now callbacks are stored more carefully.
     Patch by Aleksandr Balezin.

   - bpo-37163(184): The 'obj' argument of *note dataclasses.replace():
     1809. is positional-only now.

   - bpo-37085(185): Add the optional Linux SocketCAN Broadcast Manager
     constants, used as flags to configure the BCM behaviour, in the
     socket module.  Patch by Karl Ding.

   - bpo-37328(186): ‘HTMLParser.unescape’ is removed.  It was
     undocumented and deprecated since Python 3.4.

   - bpo-37305(187): Add .webmanifest -> application/manifest+json to
     list of recognized file types and content type headers

   - bpo-37320(188): ‘aifc.openfp()’ alias to ‘aifc.open()’,
     ‘sunau.openfp()’ alias to ‘sunau.open()’, and ‘wave.openfp()’ alias
     to ‘wave.open()’ have been removed.  They were deprecated since
     Python 3.7.

   - bpo-37315(189): Deprecated accepting floats with integral value
     (like ‘5.0’) in *note math.factorial(): 951.

   - bpo-37312(190): ‘_dummy_thread’ and ‘dummy_threading’ modules have
     been removed.  These modules were deprecated since Python 3.7 which
     requires threading support.

   - bpo-33972(191): Email with single part but content-type set to
     ‘multipart/*’ doesn’t raise AttributeError anymore.

   - bpo-37280(192): Use threadpool for reading from file for sendfile
     fallback mode.

   - bpo-37279(193): Fix asyncio sendfile support when sendfile sends
     extra data in fallback mode.

   - bpo-19865(194): *note ctypes.create_unicode_buffer(): 1b5f. now
     also supports non-BMP characters on platforms with 16-bit ‘wchar_t’
     (for example, Windows and AIX).

   - bpo-37266(195): In a subinterpreter, spawning a daemon thread now
     raises an exception.  Daemon threads were never supported in
     subinterpreters.  Previously, the subinterpreter finalization
     crashed with a Python fatal error if a daemon thread was still
     running.

   - bpo-37210(196): Allow pure Python implementation of *note pickle:
     a6. to work even when the C ‘_pickle’ module is unavailable.

   - bpo-21872(197): Fix *note lzma: 8a.: module decompresses data
     incompletely.  When decompressing a FORMAT_ALONE format file, and
     it doesn’t have the end marker, sometimes the last one to dozens
     bytes can’t be output.  Patch by Ma Lin.

   - bpo-35922(198): Fix ‘RobotFileParser.crawl_delay()’ and
     ‘RobotFileParser.request_rate()’ to return ‘None’ rather than raise
     *note AttributeError: 34e. when no relevant rule is defined in the
     robots.txt file.  Patch by Rémi Lapeyre.

   - bpo-35766(199): Change the format of feature_version to be a
     (major, minor) tuple.

   - bpo-36607(200): Eliminate *note RuntimeError: 195. raised by *note
     asyncio.all_tasks(): 960. if internal tasks weak set is changed by
     another thread during iteration.

   - bpo-18748(201): ‘_pyio.IOBase’ destructor now does nothing if
     getting the ‘closed’ attribute fails to better mimic ‘_io.IOBase’
     finalizer.

   - bpo-36402(202): Fix a race condition at Python shutdown when
     waiting for threads.  Wait until the Python thread state of all
     non-daemon threads get deleted (join all non-daemon threads),
     rather than just wait until non-daemon Python threads complete.

   - bpo-37206(203): Default values which cannot be represented as
     Python objects no longer improperly represented as ‘None’ in
     function signatures.

   - bpo-37111(204): Added ‘encoding’ and ‘errors’ keyword parameters to
     ‘logging.basicConfig’.

   - bpo-12144(205): Ensure cookies with ‘expires’ attribute are handled
     in ‘CookieJar.make_cookies()’.

   - bpo-34886(206): Fix an unintended ValueError from *note
     subprocess.run(): ba4. when checking for conflicting 'input' and
     'stdin' or 'capture_output' and 'stdout' or 'stderr' args when they
     were explicitly provided but with ‘None’ values within a passed in
     ‘**kwargs’ dict rather than as passed directly by name.  Patch
     contributed by Rémi Lapeyre.

   - bpo-37173(207): The exception message for ‘inspect.getfile()’ now
     correctly reports the passed class rather than the builtins module.

   - bpo-37178(208): Give math.perm() a one argument form that means the
     same as math.factorial().

   - bpo-37178(209): For math.perm(n, k), let k default to n, giving the
     same result as factorial.

   - bpo-37165(210): Converted _collections._count_elements to use the
     Argument Clinic.

   - bpo-34767(211): Do not always create a *note collections.deque:
     5df. in *note asyncio.Lock: a80.

   - bpo-37158(212): Speed-up statistics.fmean() by switching from a
     function to a generator.

   - bpo-34282(213): Remove ‘Enum._convert’ method, deprecated in 3.8.

   - bpo-37150(214): ‘argparse._ActionsContainer.add_argument’ now
     throws error, if someone accidentally pass FileType class object
     instead of instance of FileType as ‘type’ argument.

   - bpo-28724(215): The socket module now has the *note
     socket.send_fds(): 93d. and ‘socket.recv.fds()’ methods.
     Contributed by Joannah Nanjekye, Shinya Okano and Victor Stinner.

   - bpo-35621(216): Support running asyncio subprocesses when execution
     event loop in a thread on UNIX.

   - bpo-36520(217): Lengthy email headers with UTF-8 characters are now
     properly encoded when they are folded.  Patch by Jeffrey Kintscher.

   - bpo-30835(218): Fixed a bug in email parsing where a message with
     invalid bytes in content-transfer-encoding of a multipart message
     can cause an AttributeError.  Patch by Andrew Donnellan.

   - bpo-31163(219): pathlib.Path instance’s rename and replace methods
     now return the new Path instance.

   - bpo-25068(220): *note urllib.request.ProxyHandler: 1b60. now
     lowercases the keys of the passed dictionary.

   - bpo-26185(221): Fix *note repr(): 803. on empty ‘ZipInfo’ object.
     Patch by Mickaël Schoentgen.

   - bpo-21315(222): Email headers containing RFC2047 encoded words are
     parsed despite the missing whitespace, and a defect registered.
     Also missing trailing whitespace after encoded words is now
     registered as a defect.

   - bpo-31904(223): Port test_datetime to VxWorks: skip zoneinfo tests
     on VxWorks

   - bpo-35805(224): Add parser for Message-ID header and add it to
     default HeaderRegistry.  This should prevent folding of Message-ID
     using RFC 2048 encoded words.

   - bpo-36871(225): Ensure method signature is used instead of
     constructor signature of a class while asserting mock object
     against method calls.  Patch by Karthikeyan Singaravelan.

   - bpo-35070(226): posix.getgrouplist() now works correctly when the
     user belongs to NGROUPS_MAX supplemental groups.  Patch by Jeffrey
     Kintscher.

   - bpo-31783(227): Fix race condition in ThreadPoolExecutor when
     worker threads are created during interpreter shutdown.

   - bpo-36582(228): Fix ‘UserString.encode()’ to correctly return
     ‘bytes’ rather than a ‘UserString’ instance.

   - bpo-32424(229): Deprecate xml.etree.ElementTree.Element.copy() in
     favor of copy.copy().

     Patch by Gordon P. Hemsley

   - bpo-36564(230): Fix infinite loop in email header folding logic
     that would be triggered when an email policy’s max_line_length is
     not long enough to include the required markup and any values in
     the message.  Patch by Paul Ganssle

   - bpo-36543(231): Removed methods Element.getchildren(),
     Element.getiterator() and ElementTree.getiterator() and the
     xml.etree.cElementTree module.

   - bpo-36409(232): Remove the old plistlib API deprecated in Python
     3.4

   - bpo-36302(233): distutils sorts source file lists so that Extension
     .so files build more reproducibly by default

   - bpo-36250(234): Ignore ‘ValueError’ from ‘signal’ with
     ‘interaction’ in non-main thread.

   - bpo-36046(235): Added ‘user’, ‘group’ and ‘extra_groups’ parameters
     to the subprocess.Popen constructor.  Patch by Patrick McLean.

   - bpo-32627(236): Fix compile error when ‘_uuid’ headers conflicting
     included.

   - bpo-35800(237): Deprecate ‘smtpd.MailmanProxy’ ready for future
     removal.

   - bpo-35168(238): *note shlex.shlex.punctuation_chars: 1b61. is now a
     read-only property.

   - bpo-8538(239): Add support for boolean actions like ‘--foo’ and
     ‘--no-foo’ to argparse.  Patch contributed by Rémi Lapeyre.

   - bpo-20504(240): Fixes a bug in ‘cgi’ module when a
     multipart/form-data request has no ‘Content-Length’ header.

   - bpo-25988(241): The abstract base classes in *note collections.abc:
     1e. no longer are exposed in the regular *note collections: 1d.
     module.

   - bpo-11122(242): Distutils won’t check for rpmbuild in specified
     paths only.

   - bpo-34775(243): Division handling of PurePath now returns
     NotImplemented instead of raising a TypeError when passed something
     other than an instance of str or PurePath.  Patch by Roger Aiudi.

   - bpo-34749(244): *note binascii.a2b_base64(): 15ae. is now up to 2
     times faster.  Patch by Sergey Fedoseev.

   - bpo-34519(245): Add additional aliases for HP Roman 8.  Patch by
     Michael Osipov.

   - bpo-28009(246): Fix uuid.getnode() on platforms with ‘.’ as MAC
     Addr delimiter as well fix for MAC Addr format that omits a leading
     0 in MAC Addr values.  Currently, AIX is the only know platform
     with these settings.  Patch by Michael Felt.

   - bpo-30618(247): Add *note readlink(): 928.  Patch by Girts
     Folkmanis.

   - bpo-32498(248): Made *note urllib.parse.unquote(): 189e. accept
     bytes in addition to strings.  Patch by Stein Karlsen.

   - bpo-33348(249): lib2to3 now recognizes expressions after ‘*’ and
     ‘**’ like in ‘f(*[] or [])’.

   - bpo-32689(250): Update *note shutil.move(): a6a. function to allow
     for Path objects to be used as source argument.  Patch by Emily
     Morehouse and Maxwell “5.13b” McKinnon.

   - bpo-32820(251): Added ‘__format__’ to IPv4 and IPv6 classes.
     Always outputs a fully zero-padded string.  Supports b/x/n
     modifiers (bin/hex/native format).  Native format for IPv4 is bin,
     native format for IPv6 is hex.  Also supports ‘#’ and ‘_’
     modifiers.

   - bpo-27657(252): Fix urllib.parse.urlparse() with numeric paths.  A
     string like “path:80” is no longer parsed as a path but as a scheme
     (“path”) and a path (“80”).

   - bpo-4963(253): Fixed non-deterministic behavior related to
     mimetypes extension mapping and module reinitialization.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36589

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38807

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38724

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38786

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38785

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38723

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27805

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38438

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38761

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38716

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38713

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38692

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38692

   (14) https://bugs.python.org/issue?@action=redirect&bpo=38602

   (15) https://bugs.python.org/issue?@action=redirect&bpo=38334

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38312

   (17) https://bugs.python.org/issue?@action=redirect&bpo=38586

   (18) https://bugs.python.org/issue?@action=redirect&bpo=38565

   (19) https://bugs.python.org/issue?@action=redirect&bpo=34679

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31202

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36321

   (22) https://bugs.python.org/issue?@action=redirect&bpo=38521

   (23) https://bugs.python.org/issue?@action=redirect&bpo=38493

   (24) https://bugs.python.org/issue?@action=redirect&bpo=38478

   (25) https://bugs.python.org/issue?@action=redirect&bpo=33604

   (26) https://bugs.python.org/issue?@action=redirect&bpo=38378

   (27) https://bugs.python.org/issue?@action=redirect&bpo=38417

   (28) https://bugs.python.org/issue?@action=redirect&bpo=38449

   (29) https://bugs.python.org/issue?@action=redirect&bpo=38431

   (30) https://bugs.python.org/issue?@action=redirect&bpo=38109

   (31) https://bugs.python.org/issue?@action=redirect&bpo=38422

   (32) https://bugs.python.org/issue?@action=redirect&bpo=38405

   (33) https://bugs.python.org/issue?@action=redirect&bpo=38332

   (34) https://bugs.python.org/issue?@action=redirect&bpo=38371

   (35) https://bugs.python.org/issue?@action=redirect&bpo=38341

   (36) https://bugs.python.org/issue?@action=redirect&bpo=38319

   (37) https://bugs.python.org/issue?@action=redirect&bpo=38242

   (38) https://bugs.python.org/issue?@action=redirect&bpo=13153

   (39) https://bugs.python.org/issue?@action=redirect&bpo=38019

   (40) https://bugs.python.org/issue?@action=redirect&bpo=38163

   (41) https://bugs.python.org/issue?@action=redirect&bpo=38161

   (42) https://bugs.python.org/issue?@action=redirect&bpo=38216

   (43) https://bugs.python.org/issue?@action=redirect&bpo=30458

   (44) https://bugs.python.org/issue?@action=redirect&bpo=28286

   (45) https://bugs.python.org/issue?@action=redirect&bpo=38108

   (46) https://bugs.python.org/issue?@action=redirect&bpo=38265

   (47) https://bugs.python.org/issue?@action=redirect&bpo=38112

   (48) https://bugs.python.org/issue?@action=redirect&bpo=38248

   (49) https://bugs.python.org/issue?@action=redirect&bpo=38237

   (50) https://bugs.python.org/issue?@action=redirect&bpo=34002

   (51) https://bugs.python.org/issue?@action=redirect&bpo=38191

   (52) https://bugs.python.org/issue?@action=redirect&bpo=38155

   (53) https://bugs.python.org/issue?@action=redirect&bpo=38185

   (54) https://bugs.python.org/issue?@action=redirect&bpo=38136

   (55) https://bugs.python.org/issue?@action=redirect&bpo=37828

   (56) https://bugs.python.org/issue?@action=redirect&bpo=38175

   (57) https://bugs.python.org/issue?@action=redirect&bpo=33936

   (58) https://bugs.python.org/issue?@action=redirect&bpo=34706

   (59) https://bugs.python.org/issue?@action=redirect&bpo=38153

   (60) https://bugs.python.org/issue?@action=redirect&bpo=38115

   (61) https://bugs.python.org/issue?@action=redirect&bpo=38148

   (62) https://bugs.python.org/issue?@action=redirect&bpo=38142

   (63) https://bugs.python.org/issue?@action=redirect&bpo=9216

   (64) https://bugs.python.org/issue?@action=redirect&bpo=36991

   (65) https://bugs.python.org/issue?@action=redirect&bpo=38134

   (66) https://bugs.python.org/issue?@action=redirect&bpo=38132

   (67) https://bugs.python.org/issue?@action=redirect&bpo=38008

   (68) https://bugs.python.org/issue?@action=redirect&bpo=34037

   (69) https://bugs.python.org/issue?@action=redirect&bpo=37405

   (70) https://bugs.python.org/issue?@action=redirect&bpo=38121

   (71) https://bugs.python.org/issue?@action=redirect&bpo=38110

   (72) https://bugs.python.org/issue?@action=redirect&bpo=38093

   (73) https://bugs.python.org/issue?@action=redirect&bpo=37488

   (74) https://bugs.python.org/issue?@action=redirect&bpo=35640

   (75) https://bugs.python.org/issue?@action=redirect&bpo=38086

   (76) 
https://gitlab.com/python-devs/importlib_metadata/blob/0.21/importlib_metadata/docs/changelog.rst

   (77) https://bugs.python.org/issue?@action=redirect&bpo=37251

   (78) https://bugs.python.org/issue?@action=redirect&bpo=38037

   (79) https://bugs.python.org/issue?@action=redirect&bpo=38066

   (80) https://bugs.python.org/issue?@action=redirect&bpo=38059

   (81) https://bugs.python.org/issue?@action=redirect&bpo=38049

   (82) https://bugs.python.org/issue?@action=redirect&bpo=37953

   (83) https://bugs.python.org/issue?@action=redirect&bpo=38026

   (84) https://bugs.python.org/issue?@action=redirect&bpo=35923

   (85) https://bugs.python.org/issue?@action=redirect&bpo=38010

   (86) https://bugs.python.org/issue?@action=redirect&bpo=38006

   (87) https://bugs.python.org/issue?@action=redirect&bpo=37995

   (88) https://bugs.python.org/issue?@action=redirect&bpo=34410

   (89) https://bugs.python.org/issue?@action=redirect&bpo=37140

   (90) https://bugs.python.org/issue?@action=redirect&bpo=37587

   (91) https://bugs.python.org/issue?@action=redirect&bpo=37834

   (92) https://bugs.python.org/issue?@action=redirect&bpo=10978

   (93) https://bugs.python.org/issue?@action=redirect&bpo=37972

   (94) https://bugs.python.org/issue?@action=redirect&bpo=37965

   (95) https://bugs.python.org/issue?@action=redirect&bpo=37964

   (96) https://bugs.python.org/issue?@action=redirect&bpo=37960

   (97) https://bugs.python.org/issue?@action=redirect&bpo=37961

   (98) https://bugs.python.org/issue?@action=redirect&bpo=37951

   (99) https://bugs.python.org/issue?@action=redirect&bpo=36205

   (100) https://bugs.python.org/issue?@action=redirect&bpo=37950

   (101) https://bugs.python.org/issue?@action=redirect&bpo=34679

   (102) https://bugs.python.org/issue?@action=redirect&bpo=36917

   (103) https://bugs.python.org/issue?@action=redirect&bpo=37798

   (104) https://bugs.python.org/issue?@action=redirect&bpo=26589

   (105) https://bugs.python.org/issue?@action=redirect&bpo=37915

   (106) https://bugs.python.org/issue?@action=redirect&bpo=32554

   (107) https://bugs.python.org/issue?@action=redirect&bpo=9938

   (108) https://bugs.python.org/issue?@action=redirect&bpo=37851

   (109) https://bugs.python.org/issue?@action=redirect&bpo=32793

   (110) https://bugs.python.org/issue?@action=redirect&bpo=37885

   (111) https://bugs.python.org/issue?@action=redirect&bpo=37868

   (112) https://bugs.python.org/issue?@action=redirect&bpo=37811

   (113) https://bugs.python.org/issue?@action=redirect&bpo=37863

   (114) https://bugs.python.org/issue?@action=redirect&bpo=21131

   (115) https://bugs.python.org/issue?@action=redirect&bpo=37798

   (116) https://bugs.python.org/issue?@action=redirect&bpo=37804

   (117) https://bugs.python.org/issue?@action=redirect&bpo=37819

   (118) https://bugs.python.org/issue?@action=redirect&bpo=14465

   (119) https://bugs.python.org/issue?@action=redirect&bpo=37810

   (120) https://bugs.python.org/issue?@action=redirect&bpo=37772

   (121) https://bugs.python.org/issue?@action=redirect&bpo=18578

   (122) https://bugs.python.org/issue?@action=redirect&bpo=37785

   (123) https://bugs.python.org/issue?@action=redirect&bpo=34488

   (124) https://bugs.python.org/issue?@action=redirect&bpo=37449

   (125) https://bugs.python.org/issue?@action=redirect&bpo=28292

   (126) https://bugs.python.org/issue?@action=redirect&bpo=18049

   (127) https://bugs.python.org/issue?@action=redirect&bpo=37742

   (128) https://bugs.python.org/issue?@action=redirect&bpo=37738

   (129) https://bugs.python.org/issue?@action=redirect&bpo=37723

   (130) https://bugs.python.org/issue?@action=redirect&bpo=35943

   (131) https://bugs.python.org/issue?@action=redirect&bpo=32178

   (132) https://bugs.python.org/issue?@action=redirect&bpo=37268

   (133) https://bugs.python.org/issue?@action=redirect&bpo=11953

   (134) https://bugs.python.org/issue?@action=redirect&bpo=37685

   (135) https://bugs.python.org/issue?@action=redirect&bpo=37697

   (136) 
https://gitlab.com/python-devs/importlib_metadata/-/milestones/20

   (137) https://bugs.python.org/issue?@action=redirect&bpo=37695

   (138) https://bugs.python.org/issue?@action=redirect&bpo=37689

   (139) https://bugs.python.org/issue?@action=redirect&bpo=29553

   (140) https://bugs.python.org/issue?@action=redirect&bpo=37691

   (141) https://bugs.python.org/issue?@action=redirect&bpo=37685

   (142) https://bugs.python.org/issue?@action=redirect&bpo=37354

   (143) https://bugs.python.org/issue?@action=redirect&bpo=37664

   (144) https://bugs.python.org/issue?@action=redirect&bpo=37663

   (145) https://bugs.python.org/issue?@action=redirect&bpo=37642

   (146) https://bugs.python.org/issue?@action=redirect&bpo=36161

   (147) https://bugs.python.org/issue?@action=redirect&bpo=36324

   (148) https://bugs.python.org/issue?@action=redirect&bpo=37555

   (149) https://bugs.python.org/issue?@action=redirect&bpo=29446

   (150) https://bugs.python.org/issue?@action=redirect&bpo=16970

   (151) https://bugs.python.org/issue?@action=redirect&bpo=34443

   (152) https://bugs.python.org/issue?@action=redirect&bpo=37491

   (153) https://bugs.python.org/issue?@action=redirect&bpo=37587

   (154) https://bugs.python.org/issue?@action=redirect&bpo=18378

   (155) https://bugs.python.org/issue?@action=redirect&bpo=37579

   (156) https://bugs.python.org/issue?@action=redirect&bpo=21478

   (157) https://bugs.python.org/issue?@action=redirect&bpo=37531

   (158) https://bugs.python.org/issue?@action=redirect&bpo=37482

   (159) https://bugs.python.org/issue?@action=redirect&bpo=36993

   (160) https://bugs.python.org/issue?@action=redirect&bpo=37502

   (161) https://bugs.python.org/issue?@action=redirect&bpo=37520

   (162) https://bugs.python.org/issue?@action=redirect&bpo=18374

   (163) https://bugs.python.org/issue?@action=redirect&bpo=37424

   (164) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (165) https://bugs.python.org/issue?@action=redirect&bpo=37481

   (166) https://bugs.python.org/issue?@action=redirect&bpo=37479

   (167) https://bugs.python.org/issue?@action=redirect&bpo=37440

   (168) https://bugs.python.org/issue?@action=redirect&bpo=37437

   (169) https://bugs.python.org/issue?@action=redirect&bpo=37428

   (170) https://bugs.python.org/issue?@action=redirect&bpo=37420

   (171) https://bugs.python.org/issue?@action=redirect&bpo=37412

   (172) https://peps.python.org/pep-0529/

   (173) https://bugs.python.org/issue?@action=redirect&bpo=37406

   (174) https://bugs.python.org/issue?@action=redirect&bpo=29412

   (175) https://bugs.python.org/issue?@action=redirect&bpo=36546

   (176) https://bugs.python.org/issue?@action=redirect&bpo=37394

   (177) https://bugs.python.org/issue?@action=redirect&bpo=37376

   (178) https://bugs.python.org/issue?@action=redirect&bpo=26967

   (179) https://bugs.python.org/issue?@action=redirect&bpo=37212

   (180) https://bugs.python.org/issue?@action=redirect&bpo=37372

   (181) https://bugs.python.org/issue?@action=redirect&bpo=37345

   (182) https://bugs.python.org/issue?@action=redirect&bpo=37358

   (183) https://bugs.python.org/issue?@action=redirect&bpo=37347

   (184) https://bugs.python.org/issue?@action=redirect&bpo=37163

   (185) https://bugs.python.org/issue?@action=redirect&bpo=37085

   (186) https://bugs.python.org/issue?@action=redirect&bpo=37328

   (187) https://bugs.python.org/issue?@action=redirect&bpo=37305

   (188) https://bugs.python.org/issue?@action=redirect&bpo=37320

   (189) https://bugs.python.org/issue?@action=redirect&bpo=37315

   (190) https://bugs.python.org/issue?@action=redirect&bpo=37312

   (191) https://bugs.python.org/issue?@action=redirect&bpo=33972

   (192) https://bugs.python.org/issue?@action=redirect&bpo=37280

   (193) https://bugs.python.org/issue?@action=redirect&bpo=37279

   (194) https://bugs.python.org/issue?@action=redirect&bpo=19865

   (195) https://bugs.python.org/issue?@action=redirect&bpo=37266

   (196) https://bugs.python.org/issue?@action=redirect&bpo=37210

   (197) https://bugs.python.org/issue?@action=redirect&bpo=21872

   (198) https://bugs.python.org/issue?@action=redirect&bpo=35922

   (199) https://bugs.python.org/issue?@action=redirect&bpo=35766

   (200) https://bugs.python.org/issue?@action=redirect&bpo=36607

   (201) https://bugs.python.org/issue?@action=redirect&bpo=18748

   (202) https://bugs.python.org/issue?@action=redirect&bpo=36402

   (203) https://bugs.python.org/issue?@action=redirect&bpo=37206

   (204) https://bugs.python.org/issue?@action=redirect&bpo=37111

   (205) https://bugs.python.org/issue?@action=redirect&bpo=12144

   (206) https://bugs.python.org/issue?@action=redirect&bpo=34886

   (207) https://bugs.python.org/issue?@action=redirect&bpo=37173

   (208) https://bugs.python.org/issue?@action=redirect&bpo=37178

   (209) https://bugs.python.org/issue?@action=redirect&bpo=37178

   (210) https://bugs.python.org/issue?@action=redirect&bpo=37165

   (211) https://bugs.python.org/issue?@action=redirect&bpo=34767

   (212) https://bugs.python.org/issue?@action=redirect&bpo=37158

   (213) https://bugs.python.org/issue?@action=redirect&bpo=34282

   (214) https://bugs.python.org/issue?@action=redirect&bpo=37150

   (215) https://bugs.python.org/issue?@action=redirect&bpo=28724

   (216) https://bugs.python.org/issue?@action=redirect&bpo=35621

   (217) https://bugs.python.org/issue?@action=redirect&bpo=36520

   (218) https://bugs.python.org/issue?@action=redirect&bpo=30835

   (219) https://bugs.python.org/issue?@action=redirect&bpo=31163

   (220) https://bugs.python.org/issue?@action=redirect&bpo=25068

   (221) https://bugs.python.org/issue?@action=redirect&bpo=26185

   (222) https://bugs.python.org/issue?@action=redirect&bpo=21315

   (223) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (224) https://bugs.python.org/issue?@action=redirect&bpo=35805

   (225) https://bugs.python.org/issue?@action=redirect&bpo=36871

   (226) https://bugs.python.org/issue?@action=redirect&bpo=35070

   (227) https://bugs.python.org/issue?@action=redirect&bpo=31783

   (228) https://bugs.python.org/issue?@action=redirect&bpo=36582

   (229) https://bugs.python.org/issue?@action=redirect&bpo=32424

   (230) https://bugs.python.org/issue?@action=redirect&bpo=36564

   (231) https://bugs.python.org/issue?@action=redirect&bpo=36543

   (232) https://bugs.python.org/issue?@action=redirect&bpo=36409

   (233) https://bugs.python.org/issue?@action=redirect&bpo=36302

   (234) https://bugs.python.org/issue?@action=redirect&bpo=36250

   (235) https://bugs.python.org/issue?@action=redirect&bpo=36046

   (236) https://bugs.python.org/issue?@action=redirect&bpo=32627

   (237) https://bugs.python.org/issue?@action=redirect&bpo=35800

   (238) https://bugs.python.org/issue?@action=redirect&bpo=35168

   (239) https://bugs.python.org/issue?@action=redirect&bpo=8538

   (240) https://bugs.python.org/issue?@action=redirect&bpo=20504

   (241) https://bugs.python.org/issue?@action=redirect&bpo=25988

   (242) https://bugs.python.org/issue?@action=redirect&bpo=11122

   (243) https://bugs.python.org/issue?@action=redirect&bpo=34775

   (244) https://bugs.python.org/issue?@action=redirect&bpo=34749

   (245) https://bugs.python.org/issue?@action=redirect&bpo=34519

   (246) https://bugs.python.org/issue?@action=redirect&bpo=28009

   (247) https://bugs.python.org/issue?@action=redirect&bpo=30618

   (248) https://bugs.python.org/issue?@action=redirect&bpo=32498

   (249) https://bugs.python.org/issue?@action=redirect&bpo=33348

   (250) https://bugs.python.org/issue?@action=redirect&bpo=32689

   (251) https://bugs.python.org/issue?@action=redirect&bpo=32820

   (252) https://bugs.python.org/issue?@action=redirect&bpo=27657

   (253) https://bugs.python.org/issue?@action=redirect&bpo=4963


File: python.info,  Node: Documentation<49>,  Next: Tests<51>,  Prev: Library<133>,  Up: Python 3 9 0 alpha 1

1.23.58.4 Documentation
.......................

   - bpo-21767(1): Explicitly mention abc support in
     functools.singledispatch

   - bpo-38816(2): Provides more details about the interaction between
     ‘fork()’ and CPython’s runtime, focusing just on the C-API. This
     includes cautions about where ‘fork()’ should and shouldn’t be
     called.

   - bpo-38351(3): Modernize *note email: 3b. examples from %-formatting
     to f-strings.

   - bpo-38778(4): Document the fact that *note RuntimeError: 195. is
     raised if *note os.fork(): 197. is called in a subinterpreter.

   - bpo-38592(5): Add Brazilian Portuguese to the language switcher at
     Python Documentation website.

   - bpo-38294(6): Add list of no-longer-escaped chars to re.escape
     documentation

   - bpo-38053(7): Modernized the plistlib documentation

   - bpo-26868(8): Fix example usage of *note PyModule_AddObject(): 369.
     to properly handle errors.

   - bpo-36797(9): Fix a dead link in the distutils API Reference.

   - bpo-37977(10): Warn more strongly and clearly about pickle
     insecurity

   - bpo-37979(11): Added a link to dateutil.parser.isoparse in the
     datetime.fromisoformat documentation.  Patch by Paul Ganssle

   - bpo-12707(12): Deprecate info(), geturl(), getcode() methods in
     favor of the headers, url, and status properties, respectively, for
     HTTPResponse and addinfourl.  Also deprecate the code attribute of
     addinfourl in favor of the status attribute.  Patch by Ashwin
     Ramaswami

   - bpo-37937(13): Mention ‘frame.f_trace’ in *note sys.settrace():
     154e. docs.

   - bpo-37878(14): Make *note PyThreadState_DeleteCurrent(): 1b63.
     Internal.

   - bpo-37759(15): Beginning edits to Whatsnew 3.8

   - bpo-37726(16): Stop recommending getopt in the tutorial for command
     line argument parsing and promote argparse.

   - bpo-32910(17): Remove implementation-specific behaviour of how
     venv’s Deactivate works.

   - bpo-37256(18): Fix wording of arguments for ‘Request’ in *note
     urllib.request: 10b.

   - bpo-37284(19): Add a brief note to indicate that any new
     ‘sys.implementation’ required attributes must go through the PEP
     process.

   - bpo-30088(20): Documented that *note mailbox.Maildir: 41f.
     constructor doesn’t attempt to verify the maildir folder layout
     correctness.  Patch by Sviatoslav Sydorenko.

   - bpo-37521(21): Fix ‘importlib’ examples to insert any newly created
     modules via importlib.util.module_from_spec() immediately into
     sys.modules instead of after calling loader.exec_module().

     Thanks to Benjamin Mintz for finding the bug.

   - bpo-37456(22): Slash (‘/’) is now part of syntax.

   - bpo-37487(23): Fix PyList_GetItem index description to include 0.

   - bpo-37149(24): Replace the dead link to the Tkinter 8.5 reference
     by John Shipman, New Mexico Tech, with a link to the archive.org
     copy.

   - bpo-37478(25): Added possible exceptions to the description of
     os.chdir().

   - bpo-34903(26): Documented that in *note
     datetime.datetime.strptime(): 1714, the leading zero in some
     two-digit formats is optional.  Patch by Mike Gleen.

   - bpo-36260(27): Add decompression pitfalls to zipfile module
     documentation.

   - bpo-37004(28): In the documentation for difflib, a note was added
     explicitly warning that the results of SequenceMatcher’s ratio
     method may depend on the order of the input strings.

   - bpo-36960(29): Restructured the *note datetime: 30. docs in the
     interest of making them more user-friendly and improving
     readability.  Patch by Brad Solomon.

   - bpo-36487(30): Make C-API docs clear about what the “main”
     interpreter is.

   - bpo-23460(31): The documentation for decimal string formatting
     using the ‘:g’ specifier has been updated to reflect the correct
     exponential notation cutoff point.  Original patch contributed by
     Tuomas Suutari.

   - bpo-35803(32): Document and test that ‘tempfile’ functions may
     accept a *note path-like object: 2a0. for the ‘dir’ argument.
     Patch by Anthony Sottile.

   - bpo-33944(33): Added a note about the intended use of code in .pth
     files.

   - bpo-34293(34): Fix the Doc/Makefile regarding PAPER environment
     variable and PDF builds

   - bpo-25237(35): Add documentation for tkinter modules

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21767

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38816

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38351

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38778

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38592

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38294

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38053

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26868

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36797

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37977

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37979

   (12) https://bugs.python.org/issue?@action=redirect&bpo=12707

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37937

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37878

   (15) https://bugs.python.org/issue?@action=redirect&bpo=37759

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37726

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32910

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37256

   (19) https://bugs.python.org/issue?@action=redirect&bpo=37284

   (20) https://bugs.python.org/issue?@action=redirect&bpo=30088

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37521

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37456

   (23) https://bugs.python.org/issue?@action=redirect&bpo=37487

   (24) https://bugs.python.org/issue?@action=redirect&bpo=37149

   (25) https://bugs.python.org/issue?@action=redirect&bpo=37478

   (26) https://bugs.python.org/issue?@action=redirect&bpo=34903

   (27) https://bugs.python.org/issue?@action=redirect&bpo=36260

   (28) https://bugs.python.org/issue?@action=redirect&bpo=37004

   (29) https://bugs.python.org/issue?@action=redirect&bpo=36960

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36487

   (31) https://bugs.python.org/issue?@action=redirect&bpo=23460

   (32) https://bugs.python.org/issue?@action=redirect&bpo=35803

   (33) https://bugs.python.org/issue?@action=redirect&bpo=33944

   (34) https://bugs.python.org/issue?@action=redirect&bpo=34293

   (35) https://bugs.python.org/issue?@action=redirect&bpo=25237


File: python.info,  Node: Tests<51>,  Next: Build<56>,  Prev: Documentation<49>,  Up: Python 3 9 0 alpha 1

1.23.58.5 Tests
...............

   - bpo-38614(1): Fix test_communicate() of
     test_asyncio.test_subprocess: use ‘support.LONG_TIMEOUT’ (5
     minutes), instead of just 1 minute.

   - bpo-38614(2): Add timeout constants to *note test.support: e4.:
     *note LOOPBACK_TIMEOUT: 1b44, *note INTERNET_TIMEOUT: 1b45, *note
     SHORT_TIMEOUT: 1a09. and *note LONG_TIMEOUT: 1b46.

   - bpo-38502(3): test.regrtest now uses process groups in the
     multiprocessing mode (-jN command line option) if process groups
     are available: if *note os.setsid(): 1b65. and *note os.killpg():
     1b66. functions are available.

   - bpo-35998(4): Fix a race condition in
     test_asyncio.test_start_tls_server_1().  Previously, there was a
     race condition between the test main() function which replaces the
     protocol and the test ServerProto protocol which sends ANSWER once
     it gets HELLO. Now, only the test main() function is responsible to
     send data, ServerProto no longer sends data.

   - bpo-38470(5): Fix ‘test_compileall.test_compile_dir_maxlevels()’ on
     Windows without long path support: only create 3 subdirectories
     instead of between 20 and 100 subdirectories.

   - bpo-37531(6): On timeout, regrtest no longer attempts to call
     ‘popen.communicate()’ again: it can hang until all child processes
     using stdout and stderr pipes completes.  Kill the worker process
     and ignores its output.  Change also the faulthandler timeout of
     the main process from 1 minute to 5 minutes, for Python slowest
     buildbots.

   - bpo-38239(7): Fix test_gdb for Link Time Optimization (LTO) builds.

   - bpo-38275(8): test_ssl now handles disabled TLS/SSL versions
     better.  OpenSSL’s crypto policy and run-time settings are
     recognized and tests for disabled versions are skipped.  Tests also
     accept more TLS minimum_versions for platforms that override
     OpenSSL’s default with strict settings.

   - bpo-38271(9): The private keys for test_ssl were encrypted with
     3DES in traditional PKCS#5 format.  3DES and the digest algorithm
     of PKCS#5 are blocked by some strict crypto policies.  Use PKCS#8
     format with AES256 encryption instead.

   - bpo-38270(10): test.support now has a helper function to check for
     availability of a hash digest function.  Several tests are
     refactored avoid MD5 and use SHA256 instead.  Other tests are
     marked to use MD5 and skipped when MD5 is disabled.

   - bpo-37123(11): Multiprocessing test test_mymanager() now also
     expects -SIGTERM, not only exitcode 0.
     BaseManager._finalize_manager() sends SIGTERM to the manager
     process if it takes longer than 1 second to stop, which happens on
     slow buildbots.

   - bpo-38212(12): Multiprocessing tests: increase
     test_queue_feeder_donot_stop_onexc() timeout from 1 to 60 seconds.

   - bpo-38117(13): Test with OpenSSL 1.1.1d

   - bpo-38018(14): Increase code coverage for
     multiprocessing.shared_memory.

   - bpo-37805(15): Add tests for json.dump(…, skipkeys=True).  Patch by
     Donghee Na.

   - bpo-37531(16): Enhance regrtest multiprocess timeout: write a
     message when killing a worker process, catch popen.kill() and
     popen.wait() exceptions, put a timeout on the second call to
     popen.communicate().

   - bpo-37876(17): Add tests for ROT-13 codec.

   - bpo-36833(18): Added tests for ‘PyDateTime_XXX_GET_XXX()’ macros of
     the C API of the *note datetime: 30. module.  Patch by Joannah
     Nanjekye.

   - bpo-37558(19): Fix
     test_shared_memory_cleaned_after_process_termination name handling

   - bpo-37526(20): Add ‘test.support.catch_threading_exception()’:
     context manager catching *note threading.Thread: 956. exception
     using *note threading.excepthook(): 851.

   - bpo-37421(21): test_concurrent_futures now explicitly stops the
     ForkServer instance if it’s running.

   - bpo-37421(22): multiprocessing tests now stop the ForkServer
     instance if it’s running: close the “alive” file descriptor to ask
     the server to stop and then remove its UNIX address.

   - bpo-37421(23): test_distutils.test_build_ext() is now able to
     remove the temporary directory on Windows: don’t import the newly
     built C extension (“xx”) in the current process, but test it in a
     separated process.

   - bpo-37421(24): test_concurrent_futures now cleans up
     multiprocessing to remove immediately temporary directories created
     by multiprocessing.util.get_temp_dir().

   - bpo-37421(25): test_winconsoleio doesn’t leak a temporary file
     anymore: use tempfile.TemporaryFile() to remove it when the test
     completes.

   - bpo-37421(26): multiprocessing tests now explicitly call
     ‘_run_finalizers()’ to immediately remove temporary directories
     created by tests.

   - bpo-37421(27): urllib.request tests now call *note urlcleanup():
     1b67. to remove temporary files created by ‘urlretrieve()’ tests
     and to clear the ‘_opener’ global variable set by ‘urlopen()’ and
     functions calling indirectly ‘urlopen()’.

   - bpo-37472(28): Remove ‘Lib/test/outstanding_bugs.py’.

   - bpo-37199(29): Fix test failures when IPv6 is unavailable or
     disabled.

   - bpo-19696(30): Replace deprecated method “random.choose” with
     “random.choice” in “test_pkg_import.py”.

   - bpo-37335(31): Remove no longer necessary code from c locale
     coercion tests

   - bpo-37421(32): Fix test_shutil to no longer leak temporary files.

   - bpo-37411(33): Fix test_wsgiref.testEnviron() to no longer depend
     on the environment variables (don’t fail if “X” variable is set).

   - bpo-37400(34): Fix test_os.test_chown(): use os.getgroups() rather
     than grp.getgrall() to get groups.  Rename also the test to
     test_chown_gid().

   - bpo-37359(35): Add –cleanup option to python3 -m test to remove
     ‘test_python_*’ directories of previous failed jobs.  Add “make
     cleantest” to run ‘python3 -m test --cleanup’.

   - bpo-37362(36): test_gdb no longer fails if it gets an “unexpected”
     message on stderr: it now ignores stderr.  The purpose of test_gdb
     is to test that python-gdb.py commands work as expected, not to
     test gdb.

   - bpo-35998(37): Avoid TimeoutError in test_asyncio:
     test_start_tls_server_1()

   - bpo-37278(38): Fix test_asyncio ProactorLoopCtrlC: join the thread
     to prevent leaking a running thread and leaking a reference.

   - bpo-37261(39): Fix *note test.support.catch_unraisable_exception():
     1b68.: its __exit__() method now ignores unraisable exception
     raised when clearing its ‘unraisable’ attribute.

   - bpo-37069(40): regrtest now uses *note sys.unraisablehook(): 1f7.
     to mark a test as “environment altered” (ENV_CHANGED) if it emits
     an “unraisable exception”.  Moreover, regrtest logs a warning in
     this case.

     Use ‘python3 -m test --fail-env-changed’ to catch unraisable
     exceptions in tests.

   - bpo-37252(41): Fix assertions in ‘test_close’ and
     ‘test_events_mask_overflow’ devpoll tests.

   - bpo-37169(42): Rewrite ‘_PyObject_IsFreed()’ unit tests.

   - bpo-37153(43): ‘test_venv.test_multiprocessing()’ now explicitly
     calls ‘pool.terminate()’ to wait until the pool completes.

   - bpo-34001(44): Make test_ssl pass with LibreSSL. LibreSSL handles
     minimum and maximum TLS version differently than OpenSSL.

   - bpo-36919(45): Make ‘test_source_encoding.test_issue2301’
     implementation independent.  The test will work now for both
     CPython and IronPython.

   - bpo-30202(46): Update ‘test.test_importlib.test_abc’ to test
     ‘find_spec()’.

   - bpo-28009(47): Modify the test_uuid logic to test when a program is
     available AND can be used to obtain a MACADDR as basis for an UUID.
     Patch by M. Felt

   - bpo-34596(48): Fallback to a default reason when *note
     unittest.skip(): 1b69. is uncalled.  Patch by Naitree Zhu.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38614

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38614

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38502

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35998

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38470

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37531

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38239

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38275

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38271

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38270

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37123

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38212

   (13) https://bugs.python.org/issue?@action=redirect&bpo=38117

   (14) https://bugs.python.org/issue?@action=redirect&bpo=38018

   (15) https://bugs.python.org/issue?@action=redirect&bpo=37805

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37531

   (17) https://bugs.python.org/issue?@action=redirect&bpo=37876

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36833

   (19) https://bugs.python.org/issue?@action=redirect&bpo=37558

   (20) https://bugs.python.org/issue?@action=redirect&bpo=37526

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (23) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (24) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (25) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (26) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (27) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (28) https://bugs.python.org/issue?@action=redirect&bpo=37472

   (29) https://bugs.python.org/issue?@action=redirect&bpo=37199

   (30) https://bugs.python.org/issue?@action=redirect&bpo=19696

   (31) https://bugs.python.org/issue?@action=redirect&bpo=37335

   (32) https://bugs.python.org/issue?@action=redirect&bpo=37421

   (33) https://bugs.python.org/issue?@action=redirect&bpo=37411

   (34) https://bugs.python.org/issue?@action=redirect&bpo=37400

   (35) https://bugs.python.org/issue?@action=redirect&bpo=37359

   (36) https://bugs.python.org/issue?@action=redirect&bpo=37362

   (37) https://bugs.python.org/issue?@action=redirect&bpo=35998

   (38) https://bugs.python.org/issue?@action=redirect&bpo=37278

   (39) https://bugs.python.org/issue?@action=redirect&bpo=37261

   (40) https://bugs.python.org/issue?@action=redirect&bpo=37069

   (41) https://bugs.python.org/issue?@action=redirect&bpo=37252

   (42) https://bugs.python.org/issue?@action=redirect&bpo=37169

   (43) https://bugs.python.org/issue?@action=redirect&bpo=37153

   (44) https://bugs.python.org/issue?@action=redirect&bpo=34001

   (45) https://bugs.python.org/issue?@action=redirect&bpo=36919

   (46) https://bugs.python.org/issue?@action=redirect&bpo=30202

   (47) https://bugs.python.org/issue?@action=redirect&bpo=28009

   (48) https://bugs.python.org/issue?@action=redirect&bpo=34596


File: python.info,  Node: Build<56>,  Next: Windows<48>,  Prev: Tests<51>,  Up: Python 3 9 0 alpha 1

1.23.58.6 Build
...............

   - bpo-38809(1): On Windows, build scripts will now recognize and use
     python.exe from an active virtual env.

   - bpo-38684(2): Fix _hashlib build when Blake2 is disabled, but
     OpenSSL supports it.

   - bpo-38468(3): Misc/python-config.in now uses ‘getvar()’ for all
     still existing ‘sysconfig.get_config_var()’ calls.  Patch by
     Joannah Nanjekye.

   - bpo-37415(4): Fix stdatomic.h header check for ICC compiler: the
     ICC implementation lacks atomic_uintptr_t type which is needed by
     Python.

   - bpo-38301(5): In Solaris family, we must be sure to use
     ‘-D_REENTRANT’.  Patch by Jesús Cea Avión.

   - bpo-36002(6): Locate ‘llvm-profdata’ and ‘llvm-ar’ binaries using
     ‘AC_PATH_TOOL’ rather than ‘AC_PATH_TARGET_TOOL’.

   - bpo-37936(7): The ‘.gitignore’ file systematically keeps “rooted”,
     with a non-trailing slash, all the rules that are meant to apply to
     files in a specific place in the repo.  Previously, when the
     intended file to ignore happened to be at the root of the repo,
     we’d most often accidentally also ignore files and directories with
     the same name anywhere in the tree.

   - bpo-37760(8): The ‘Tools/unicode/makeunicodedata.py’ script, which
     is used for converting information from the Unicode Character
     Database into generated code and data used by the methods of *note
     str: 44f. and by the *note unicodedata: 105. module, now handles
     each character’s data as a ‘dataclass’ with named attributes,
     rather than a length-18 list of different fields.

   - bpo-37936(9): The ‘.gitignore’ file no longer applies to any files
     that are in fact tracked in the Git repository.  Patch by Greg
     Price.

   - bpo-37725(10): Change “clean” makefile target to also clean the
     program guided optimization (PGO) data.  Previously you would have
     to use “make clean” and “make profile-removal”, or “make clobber”.

   - bpo-37707(11): Mark some individual tests to skip when –pgo is
     used.  The tests marked increase the PGO task time significantly
     and likely don’t help improve optimization of the final executable.

   - bpo-36044(12): Reduce the number of unit tests run for the PGO
     generation task.  This speeds up the task by a factor of about 15x.
     Running the full unit test suite is slow.  This change may result
     in a slightly less optimized build since not as many code branches
     will be executed.  If you are willing to wait for the much slower
     build, the old behavior can be restored using ‘./configure [..]
     PROFILE_TASK=”-m test –pgo-extended”’.  We make no guarantees as to
     which PGO task set produces a faster build.  Users who care should
     run their own relevant benchmarks as results can depend on the
     environment, workload, and compiler tool chain.

   - bpo-37468(13): ‘make install’ no longer installs ‘wininst-*.exe’
     files used by distutils bdist_wininst: bdist_wininst only works on
     Windows.

   - bpo-37189(14): Many ‘PyRun_XXX()’ functions like *note
     PyRun_String(): 1b6b. were no longer exported in ‘libpython38.dll’
     by mistake.  Export them again to fix the ABI compatibility.

   - bpo-25361(15): Enables use of SSE2 instructions in Windows 32-bit
     build.

   - bpo-36210(16): Update optional extension module detection for AIX.
     ossaudiodev and spwd are not applicable for AIX, and are no longer
     reported as missing.  3rd-party packaging of ncurses (with ASIS
     support) conflicts with officially supported AIX curses library, so
     configure AIX to use libcurses.a.  However, skip trying to build
     _curses_panel.

     patch by M Felt

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38809

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38684

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38468

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37415

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38301

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36002

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37936

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37760

   (9) https://bugs.python.org/issue?@action=redirect&bpo=37936

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37725

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37707

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36044

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37468

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37189

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25361

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36210


File: python.info,  Node: Windows<48>,  Next: macOS<39>,  Prev: Build<56>,  Up: Python 3 9 0 alpha 1

1.23.58.7 Windows
.................

   - bpo-38589(1): Fixes HTML Help shortcut when Windows is not
     installed to C drive

   - bpo-38453(2): Ensure ntpath.realpath() correctly resolves relative
     paths.

   - bpo-38519(3): Restores the internal C headers that were missing
     from the nuget.org and Microsoft Store packages.

   - bpo-38492(4): Remove ‘pythonw.exe’ dependency on the Microsoft C++
     runtime.

   - bpo-38344(5): Fix error message in activate.bat

   - bpo-38359(6): Ensures ‘pyw.exe’ launcher reads correct registry
     key.

   - bpo-38355(7): Fixes ‘ntpath.realpath’ failing on ‘sys.executable’.

   - bpo-38117(8): Update bundled OpenSSL to 1.1.1d

   - bpo-38092(9): Reduce overhead when using multiprocessing in a
     Windows virtual environment.

   - bpo-38133(10): Allow py.exe launcher to locate installations from
     the Microsoft Store and improve display of active virtual
     environments.

   - bpo-38114(11): The ‘pip.ini’ is no longer included in the Nuget
     package.

   - bpo-32592(12): Set Windows 8 as the minimum required version for
     API support

   - bpo-36634(13): *note os.cpu_count(): 1c5. now returns active
     processors rather than maximum processors.

   - bpo-36634(14): venv activate.bat now works when the existing
     variables contain double quote characters.

   - bpo-38081(15): Prevent error calling *note os.path.realpath(): 225.
     on ‘'NUL'’.

   - bpo-38087(16): Fix case sensitivity in test_pathlib and
     test_ntpath.

   - bpo-38088(17): Fixes distutils not finding vcruntime140.dll with
     only the v142 toolset installed.

   - bpo-37283(18): Ensure command-line and unattend.xml setting
     override previously detected states in Windows installer.

   - bpo-38030(19): Fixes *note os.stat(): 4a3. failing for block
     devices on Windows

   - bpo-38020(20): Fixes potential crash when calling *note
     os.readlink(): 929. (or indirectly through *note realpath(): 225.)
     on a file that is not a supported link.

   - bpo-37705(21): Improve the implementation of ‘winerror_to_errno()’.

   - bpo-37549(22): *note os.dup(): 1b6d. no longer fails for standard
     streams on Windows 7.

   - bpo-1311(23): The ‘nul’ file on Windows now returns True from *note
     exists(): a1b. and a valid result from *note os.stat(): 4a3. with
     ‘S_IFCHR’ set.

   - bpo-9949(24): Enable support for following symlinks in
     ‘os.realpath()’.

   - bpo-37834(25): Treat all name surrogate reparse points on Windows
     in *note os.lstat(): 4a4. and other reparse points as regular files
     in *note os.stat(): 4a3.

   - bpo-36266(26): Add the module name in the formatted error message
     when DLL load fail happens during module import in
     ‘_PyImport_FindSharedFuncptrWindows()’.  Patch by Srinivas
     Nyayapati.

   - bpo-25172(27): Trying to import the ‘crypt’ module on Windows will
     result in an *note ImportError: 41c. with a message explaining that
     the module isn’t supported on Windows.  On other platforms, if the
     underlying ‘_crypt’ module is not available, the ImportError will
     include a message explaining the problem.

   - bpo-37778(28): Fixes the icons used for file associations to the
     Microsoft Store package.

   - bpo-37734(29): Fix use of registry values to launch Python from
     Microsoft Store app.

   - bpo-37702(30): Fix memory leak on Windows in creating an SSLContext
     object or running ‘urllib.request.urlopen('https://...')’.

   - bpo-37672(31): Switch Windows Store package’s pip to use bundled
     ‘pip.ini’ instead of ‘PIP_USER’ variable.

   - bpo-10945(32): Officially drop support for creating bdist_wininst
     installers on non-Windows systems.

   - bpo-37445(33): Include the ‘FORMAT_MESSAGE_IGNORE_INSERTS’ flag in
     ‘FormatMessageW()’ calls.

   - bpo-37369(34): Fixes path for *note sys.executable: 3bb. when
     running from the Microsoft Store.

   - bpo-37380(35): Don’t collect unfinished processes with
     ‘subprocess._active’ on Windows to cleanup later.  Patch by Ruslan
     Kuprieiev.

   - bpo-37351(36): Removes libpython38.a from standard Windows
     distribution.

   - bpo-35360(37): Update Windows builds to use SQLite 3.28.0.

   - bpo-37267(38): On Windows, *note os.dup(): 1b6d. no longer creates
     an inheritable fd when handling a character file.

   - bpo-36779(39): Ensure ‘time.tzname’ is correct on Windows when the
     active code page is set to CP_UTF7 or CP_UTF8.

   - bpo-32587(40): Make *note winreg.REG_MULTI_SZ: 1b6e. support
     zero-length strings.

   - bpo-28269(41): Replace use of ‘strcasecmp()’ for the system
     function ‘_stricmp()’.  Patch by Minmin Gong.

   - bpo-36590(42): Add native Bluetooth RFCOMM support to socket
     module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38589

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38453

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38519

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38492

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38344

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38359

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38355

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38117

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38092

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38133

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38114

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32592

   (13) https://bugs.python.org/issue?@action=redirect&bpo=36634

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36634

   (15) https://bugs.python.org/issue?@action=redirect&bpo=38081

   (16) https://bugs.python.org/issue?@action=redirect&bpo=38087

   (17) https://bugs.python.org/issue?@action=redirect&bpo=38088

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37283

   (19) https://bugs.python.org/issue?@action=redirect&bpo=38030

   (20) https://bugs.python.org/issue?@action=redirect&bpo=38020

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37705

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37549

   (23) https://bugs.python.org/issue?@action=redirect&bpo=1311

   (24) https://bugs.python.org/issue?@action=redirect&bpo=9949

   (25) https://bugs.python.org/issue?@action=redirect&bpo=37834

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36266

   (27) https://bugs.python.org/issue?@action=redirect&bpo=25172

   (28) https://bugs.python.org/issue?@action=redirect&bpo=37778

   (29) https://bugs.python.org/issue?@action=redirect&bpo=37734

   (30) https://bugs.python.org/issue?@action=redirect&bpo=37702

   (31) https://bugs.python.org/issue?@action=redirect&bpo=37672

   (32) https://bugs.python.org/issue?@action=redirect&bpo=10945

   (33) https://bugs.python.org/issue?@action=redirect&bpo=37445

   (34) https://bugs.python.org/issue?@action=redirect&bpo=37369

   (35) https://bugs.python.org/issue?@action=redirect&bpo=37380

   (36) https://bugs.python.org/issue?@action=redirect&bpo=37351

   (37) https://bugs.python.org/issue?@action=redirect&bpo=35360

   (38) https://bugs.python.org/issue?@action=redirect&bpo=37267

   (39) https://bugs.python.org/issue?@action=redirect&bpo=36779

   (40) https://bugs.python.org/issue?@action=redirect&bpo=32587

   (41) https://bugs.python.org/issue?@action=redirect&bpo=28269

   (42) https://bugs.python.org/issue?@action=redirect&bpo=36590


File: python.info,  Node: macOS<39>,  Next: IDLE<36>,  Prev: Windows<48>,  Up: Python 3 9 0 alpha 1

1.23.58.8 macOS
...............

   - bpo-38117(1): Updated OpenSSL to 1.1.1d in macOS installer.

   - bpo-38089(2): Move Azure Pipelines to latest VM versions and make
     macOS tests optional

   - bpo-18049(3): Increase the default stack size of threads from 5MB
     to 16MB on macOS, to match the stack size of the main thread.  This
     avoids crashes on deep recursion in threads.

   - bpo-34602(4): Avoid test suite failures on macOS by no longer
     calling resource.setrlimit to increase the process stack size limit
     at runtime.  The runtime change is no longer needed since the
     interpreter is being built with a larger default stack size.

   - bpo-35360(5): Update macOS installer to use SQLite 3.28.0.

   - bpo-34631(6): Updated OpenSSL to 1.1.1c in macOS installer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38117

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38089

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18049

   (4) https://bugs.python.org/issue?@action=redirect&bpo=34602

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35360

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34631


File: python.info,  Node: IDLE<36>,  Next: Tools/Demos<26>,  Prev: macOS<39>,  Up: Python 3 9 0 alpha 1

1.23.58.9 IDLE
..............

   - bpo-26353(1): Stop adding newline when saving an IDLE shell window.

   - bpo-4630(2): Add an option to toggle IDLE’s cursor blink for shell,
     editor, and output windows.  See Settings, General, Window
     Preferences, Cursor Blink.  Patch by Zackery Spytz.

   - bpo-38598(3): Do not try to compile IDLE shell or output windows

   - bpo-36698(4): IDLE no longer fails when write non-encodable
     characters to stderr.  It now escapes them with a backslash, as the
     regular Python interpreter.  Added the ‘errors’ field to the
     standard streams.

   - bpo-35379(5): When exiting IDLE, catch any AttributeError.  One
     happens when EditorWindow.close is called twice.  Printing a
     traceback, when IDLE is run from a terminal, is useless and
     annoying.

   - bpo-38183(6): To avoid problems, test_idle ignores the user config
     directory.  It no longer tries to create or access .idlerc or any
     files within.  Users must run IDLE to discover problems with saving
     settings.

   - bpo-38077(7): IDLE no longer adds ‘argv’ to the user namespace when
     initializing it.  This bug only affected 3.7.4 and 3.8.0b2 to
     3.8.0b4.

   - bpo-38041(8): Shell restart lines now fill the window width, always
     start with ‘=’, and avoid wrapping unnecessarily.  The line will
     still wrap if the included file name is long relative to the width.

   - bpo-35771(9): To avoid occasional spurious test_idle failures on
     slower machines, increase the ‘hover_delay’ in test_tooltip.

   - bpo-37824(10): Properly handle user input warnings in IDLE shell.
     Cease turning SyntaxWarnings into SyntaxErrors.

   - bpo-37929(11): IDLE Settings dialog now closes properly when there
     is no shell window.

   - bpo-37902(12): Add mousewheel scrolling for IDLE module, path, and
     stack browsers.  Patch by George Zhang.

   - bpo-37849(13): Fixed completions list appearing too high or low
     when shown above the current line.

   - bpo-36419(14): Refactor IDLE autocomplete and improve testing.

   - bpo-37748(15): Reorder the Run menu.  Put the most common choice,
     Run Module, at the top.

   - bpo-37692(16): Improve highlight config sample with example shell
     interaction and better labels for shell elements.

   - bpo-37628(17): Settings dialog no longer expands with font size.

   - bpo-37627(18): Initialize the Customize Run dialog with the command
     line arguments most recently entered before.  The user can
     optionally edit before submitting them.

   - bpo-33610(19): Fix code context not showing the correct context
     when first toggled on.

   - bpo-37530(20): Optimize code context to reduce unneeded background
     activity.  Font and highlight changes now occur along with text
     changes instead of after a random delay.

   - bpo-27452(21): Cleanup ‘config.py’ by inlining ‘RemoveFile’ and
     simplifying the handling of ‘file’ in ‘CreateConfigHandlers’.

   - bpo-37325(22): Fix tab focus traversal order for help source and
     custom run dialogs.

   - bpo-37321(23): Both subprocess connection error messages now refer
     to the ‘Startup failure’ section of the IDLE doc.

   - bpo-17535(24): Add optional line numbers for IDLE editor windows.
     Windows open without line numbers unless set otherwise in the
     General tab of the configuration dialog.

   - bpo-26806(25): To compensate for stack frames added by IDLE and
     avoid possible problems with low recursion limits, add 30 to limits
     in the user code execution process.  Subtract 30 when reporting
     recursion limits to make this addition mostly transparent.

   - bpo-37177(26): Properly ‘attach’ search dialogs to their main
     window so that they behave like other dialogs and do not get hidden
     behind their main window.

   - bpo-37039(27): Adjust “Zoom Height” to individual screens by
     momentarily maximizing the window on first use with a particular
     screen.  Changing screen settings may invalidate the saved height.
     While a window is maximized, “Zoom Height” has no effect.

   - bpo-35763(28): Make calltip reminder about ‘/’ meaning
     positional-only less obtrusive by only adding it when there is room
     on the first line.

   - bpo-5680(29): Add ‘Run… Customized’ to the Run menu to run a module
     with customized settings.  Any ‘command line arguments’ entered are
     added to sys.argv.  One can suppress the normal Shell main module
     restart.

   - bpo-36390(30): Gather Format menu functions into format.py.
     Combine paragraph.py, rstrip.py, and format methods from editor.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26353

   (2) https://bugs.python.org/issue?@action=redirect&bpo=4630

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38598

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36698

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35379

   (6) https://bugs.python.org/issue?@action=redirect&bpo=38183

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38077

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38041

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35771

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37824

   (11) https://bugs.python.org/issue?@action=redirect&bpo=37929

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37902

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37849

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36419

   (15) https://bugs.python.org/issue?@action=redirect&bpo=37748

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37692

   (17) https://bugs.python.org/issue?@action=redirect&bpo=37628

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37627

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33610

   (20) https://bugs.python.org/issue?@action=redirect&bpo=37530

   (21) https://bugs.python.org/issue?@action=redirect&bpo=27452

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37325

   (23) https://bugs.python.org/issue?@action=redirect&bpo=37321

   (24) https://bugs.python.org/issue?@action=redirect&bpo=17535

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26806

   (26) https://bugs.python.org/issue?@action=redirect&bpo=37177

   (27) https://bugs.python.org/issue?@action=redirect&bpo=37039

   (28) https://bugs.python.org/issue?@action=redirect&bpo=35763

   (29) https://bugs.python.org/issue?@action=redirect&bpo=5680

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36390


File: python.info,  Node: Tools/Demos<26>,  Next: C API<51>,  Prev: IDLE<36>,  Up: Python 3 9 0 alpha 1

1.23.58.10 Tools/Demos
......................

   - bpo-38118(1): Update Valgrind suppression file to ignore a false
     alarm in *note PyUnicode_Decode(): 1b72. when using GCC builtin
     strcmp().

   - bpo-38347(2): pathfix.py: Assume all files that end on ‘.py’ are
     Python scripts when working recursively.

   - bpo-37803(3): pdb’s ‘--help’ and ‘--version’ long options now work.

   - bpo-37942(4): Improve ArgumentClinic converter for floats.

   - bpo-37704(5): Remove ‘Tools/scripts/h2py.py’: use cffi to access a
     C API in Python.

   - bpo-37675(6): 2to3 now works when run from a zipped standard
     library.

   - bpo-37034(7): Argument Clinic now uses the argument name on errors
     with keyword-only argument instead of their position.  Patch
     contributed by Rémi Lapeyre.

   - bpo-37064(8): Add option -k to pathscript.py script: preserve
     shebang flags.  Add option -a to pathscript.py script: add flags.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=38118

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38347

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37803

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37942

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37704

   (6) https://bugs.python.org/issue?@action=redirect&bpo=37675

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37034

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37064


File: python.info,  Node: C API<51>,  Prev: Tools/Demos<26>,  Up: Python 3 9 0 alpha 1

1.23.58.11 C API
................

   - bpo-37633(1): Re-export some function compatibility wrappers for
     macros in ‘pythonrun.h’.

   - bpo-38644(2): Provide *note Py_EnterRecursiveCall(): 97d. and *note
     Py_LeaveRecursiveCall(): 97e. as regular functions for the limited
     API. Previously, there were defined as macros, but these macros
     didn’t work with the limited API which cannot access
     ‘PyThreadState.recursion_depth’ field.  Remove
     ‘_Py_CheckRecursionLimit’ from the stable ABI.

   - bpo-38650(3): The global variable *note
     PyStructSequence_UnnamedField: 98c. is now a constant and refers to
     a constant string.

   - bpo-38540(4): Fixed possible leak in *note PyArg_Parse(): 1b74. and
     similar functions for format units ‘"es#"’ and ‘"et#"’ when the
     macro ‘PY_SSIZE_T_CLEAN’ is not defined.

   - bpo-38395(5): Fix a crash in *note weakref.proxy: a5f. objects due
     to incorrect lifetime management when calling some associated
     methods that may delete the last reference to object being
     referenced by the proxy.  Patch by Pablo Galindo.

   - bpo-36389(6): The ‘_PyObject_CheckConsistency()’ function is now
     also available in release mode.  For example, it can be used to
     debug a crash in the ‘visit_decref()’ function of the GC.

   - bpo-38266(7): Revert the removal of PyThreadState_DeleteCurrent()
     with documentation.

   - bpo-38303(8): Update audioop extension module to use the stable ABI
     (PEP-384).  Patch by Tyler Kieft.

   - bpo-38234(9): ‘Py_SetPath()’ now sets *note sys.executable: 3bb. to
     the program full path (*note Py_GetProgramFullPath(): 3ba.) rather
     than to the program name (*note Py_GetProgramName(): 3bc.).

   - bpo-38234(10): Python ignored arguments passed to ‘Py_SetPath()’,
     ‘Py_SetPythonHome()’ and ‘Py_SetProgramName()’: fix Python
     initialization to use specified arguments.

   - bpo-38205(11): The *note Py_UNREACHABLE(): bd3. macro now calls
     *note Py_FatalError(): 98d.

   - bpo-38140(12): Make dict and weakref offsets opaque for C heap
     types by passing the offsets through PyMemberDef

   - bpo-15088(13): The C function ‘PyGen_NeedsFinalizing’ has been
     removed.  It was not documented, tested or used anywhere within
     CPython after the implementation of PEP 442(14).  Patch by Joannah
     Nanjekye.  (Patch by Joannah Nanjekye)

   - bpo-36763(15): Options added by ‘PySys_AddXOption()’ are now
     handled the same way than ‘PyConfig.xoptions’ and command line ‘-X’
     options.

   - bpo-37926(16): Fix a crash in ‘PySys_SetArgvEx(0, NULL, 0)’.

   - bpo-37879(17): Fix subtype_dealloc to suppress the type decref when
     the base type is a C heap type

   - bpo-37645(18): Add ‘_PyObject_FunctionStr()’ to get a user-friendly
     string representation of a function-like object.  Patch by Jeroen
     Demeyer.

   - bpo-29548(19): The functions ‘PyEval_CallObject’,
     ‘PyEval_CallFunction’, ‘PyEval_CallMethod’ and
     ‘PyEval_CallObjectWithKeywords’ are deprecated.  Use *note
     PyObject_Call(): 39f. and its variants instead.

   - bpo-37151(20): ‘PyCFunction_Call’ is now a deprecated alias of
     *note PyObject_Call(): 39f.

   - bpo-37540(21): The vectorcall protocol now requires that the caller
     passes only strings as keyword names.

   - bpo-37207(22): The vectorcall protocol is now enabled for ‘type’
     objects: set ‘tp_vectorcall’ to a vectorcall function to be used
     instead of ‘tp_new’ and ‘tp_init’ when calling the class itself.

   - bpo-21120(23): Exclude Python-ast.h, ast.h and asdl.h from the
     limited API.

   - bpo-37483(24): Add new function ‘_PyObject_CallOneArg’ for calling
     an object with one positional argument.

   - bpo-36763(25): Add *note PyConfig_SetWideStringList(): 1b75.
     function.

   - bpo-37337(26): Add fast functions for calling methods:
     ‘_PyObject_VectorcallMethod()’, ‘_PyObject_CallMethodNoArgs()’ and
     ‘_PyObject_CallMethodOneArg()’.

   - bpo-28805(27): The *note METH_FASTCALL: 1731. calling convention
     has been documented.

   - bpo-37221(28): The new function ‘PyCode_NewWithPosOnlyArgs()’
     allows to create code objects like ‘PyCode_New()’, but with an
     extra 'posonlyargcount' parameter for indicating the number of
     positonal-only arguments.

   - bpo-37215(29): Fix dtrace issue introduce by bpo-36842(30)

   - bpo-37194(31): Add a new public *note PyObject_CallNoArgs(): 39e.
     function to the C API: call a callable Python object without any
     arguments.  It is the most efficient way to call a callback without
     any argument.  On x86-64, for example,
     ‘PyObject_CallFunctionObjArgs(func, NULL)’ allocates 960 bytes on
     the stack per call, whereas ‘PyObject_CallNoArgs(func)’ only
     allocates 624 bytes per call.

   - bpo-37170(32): Fix the cast on error in *note
     PyLong_AsUnsignedLongLongMask(): 1b76.

   - bpo-35381(33): Convert posixmodule.c statically allocated types
     ‘DirEntryType’ and ‘ScandirIteratorType’ to heap-allocated types.

   - bpo-34331(34): Use singular/plural noun in error message when
     instantiating an abstract class with non-overridden abstract
     method(s).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37633

   (2) https://bugs.python.org/issue?@action=redirect&bpo=38644

   (3) https://bugs.python.org/issue?@action=redirect&bpo=38650

   (4) https://bugs.python.org/issue?@action=redirect&bpo=38540

   (5) https://bugs.python.org/issue?@action=redirect&bpo=38395

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36389

   (7) https://bugs.python.org/issue?@action=redirect&bpo=38266

   (8) https://bugs.python.org/issue?@action=redirect&bpo=38303

   (9) https://bugs.python.org/issue?@action=redirect&bpo=38234

   (10) https://bugs.python.org/issue?@action=redirect&bpo=38234

   (11) https://bugs.python.org/issue?@action=redirect&bpo=38205

   (12) https://bugs.python.org/issue?@action=redirect&bpo=38140

   (13) https://bugs.python.org/issue?@action=redirect&bpo=15088

   (14) https://peps.python.org/pep-0442/

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36763

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37926

   (17) https://bugs.python.org/issue?@action=redirect&bpo=37879

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37645

   (19) https://bugs.python.org/issue?@action=redirect&bpo=29548

   (20) https://bugs.python.org/issue?@action=redirect&bpo=37151

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37540

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37207

   (23) https://bugs.python.org/issue?@action=redirect&bpo=21120

   (24) https://bugs.python.org/issue?@action=redirect&bpo=37483

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36763

   (26) https://bugs.python.org/issue?@action=redirect&bpo=37337

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28805

   (28) https://bugs.python.org/issue?@action=redirect&bpo=37221

   (29) https://bugs.python.org/issue?@action=redirect&bpo=37215

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36842

   (31) https://bugs.python.org/issue?@action=redirect&bpo=37194

   (32) https://bugs.python.org/issue?@action=redirect&bpo=37170

   (33) https://bugs.python.org/issue?@action=redirect&bpo=35381

   (34) https://bugs.python.org/issue?@action=redirect&bpo=34331


File: python.info,  Node: Python 3 8 0 beta 1,  Next: Python 3 8 0 alpha 4,  Prev: Python 3 9 0 alpha 1,  Up: Changelog

1.23.59 Python 3.8.0 beta 1
---------------------------

'Release date: 2019-06-04'

* Menu:

* Security: Security<40>.
* Core and Builtins: Core and Builtins<132>.
* Library: Library<134>.
* Documentation: Documentation<50>.
* Tests: Tests<52>.
* Build: Build<57>.
* Windows: Windows<49>.
* macOS: macOS<40>.
* IDLE: IDLE<37>.
* Tools/Demos: Tools/Demos<27>.
* C API: C API<52>.


File: python.info,  Node: Security<40>,  Next: Core and Builtins<132>,  Up: Python 3 8 0 beta 1

1.23.59.1 Security
..................

   - bpo-35907(1): CVE 2019-9948(2): Avoid file reading by disallowing
     ‘local-file://’ and ‘local_file://’ URL schemes in
     ‘URLopener().open()’ and ‘URLopener().retrieve()’ of *note
     urllib.request: 10b.

   - bpo-33529(3): Prevent fold function used in email header encoding
     from entering infinite loop when there are too many non-ASCII
     characters in a header.

   - bpo-33164(4): Updated blake2 implementation which uses secure
     memset implementation provided by platform.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35907

   (2) https://www.cve.org/CVERecord?id=CVE-2019-9948

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33529

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33164


File: python.info,  Node: Core and Builtins<132>,  Next: Library<134>,  Prev: Security<40>,  Up: Python 3 8 0 beta 1

1.23.59.2 Core and Builtins
...........................

   - bpo-35814(1): Allow unpacking in the right hand side of annotated
     assignments.  In particular, ‘t: Tuple[int, ...] = x, y, *z’ is now
     allowed.

   - bpo-37126(2): All structseq objects are now tracked by the garbage
     collector.  Patch by Pablo Galindo.

   - bpo-37122(3): Make the 'co_argcount' attribute of code objects
     represent the total number of positional arguments (including
     positional-only arguments).  The value of 'co_posonlyargcount' can
     be used to distinguish which arguments are positional only, and the
     difference ('co_argcount' - 'co_posonlyargcount') is the number of
     positional-or-keyword arguments.  Patch by Pablo Galindo.

   - bpo-20092(4): Constructors of *note int: 257, *note float: 2f7. and
     *note complex: 2f8. will now use the *note __index__(): 720.
     special method, if available and the corresponding method *note
     __int__(): 71f, *note __float__(): 9d7. or *note __complex__():
     5ea. is not available.

   - bpo-37087(5): Add native thread ID (TID) support to OpenBSD.

   - bpo-26219(6): Implemented per opcode cache mechanism and
     ‘LOAD_GLOBAL’ instruction use it.  ‘LOAD_GLOBAL’ is now about 40%
     faster.  Contributed by Yury Selivanov, and Inada Naoki.

   - bpo-37072(7): Fix crash in PyAST_FromNodeObject() when flags is
     NULL.

   - bpo-37029(8): Freeing a great many small objects could take time
     quadratic in the number of arenas, due to using linear search to
     keep ‘obmalloc.c’’s list of usable arenas sorted by order of number
     of free memory pools.  This is accomplished without search now,
     leaving the worst-case time linear in the number of arenas.  For
     programs where this quite visibly matters (typically with more than
     100 thousand small objects alive simultaneously), this can greatly
     reduce the time needed to release their memory.

   - bpo-26423(9): Fix possible overflow in ‘wrap_lenfunc()’ when
     ‘sizeof(long) < sizeof(Py_ssize_t)’ (e.g., 64-bit Windows).

   - bpo-37050(10): Improve the AST for “debug” f-strings, which use ‘=’
     to print out the source of the expression being evaluated.  Delete
     expr_text from the FormattedValue node, and instead use a Constant
     string node (possibly merged with adjacent constant expressions
     inside the f-string).

   - bpo-22385(11): The ‘bytes.hex’, ‘bytearray.hex’, and
     ‘memoryview.hex’ methods as well as the ‘binascii.hexlify’ and
     ‘b2a_hex’ functions now have the ability to include an optional
     separator between hex bytes.  This functionality was inspired by
     MicroPython’s hexlify implementation.

   - bpo-26836(12): Add *note os.memfd_create(): a16.

   - bpo-37032(13): Added new ‘replace()’ method to the code type (*note
     types.CodeType: 2df.).

   - bpo-37007(14): Implement *note socket.if_nameindex(): a3a, *note
     socket.if_nametoindex(): a3b, and *note socket.if_indextoname():
     a3c. on Windows.

   - bpo-36829(15): *note PyErr_WriteUnraisable(): 350. now creates a
     traceback object if there is no current traceback.  Moreover, call
     *note PyErr_NormalizeException(): 3f8. and *note
     PyException_SetTraceback(): 1b7a. to normalize the exception value.
     Ignore any error.

   - bpo-36878(16): Only accept text after ‘# type: ignore’ if the first
     character is ASCII. This is to disallow things like ‘# type:
     ignoreé’.

   - bpo-36878(17): Store text appearing after a ‘# type: ignore’
     comment in the AST. For example a type ignore like ‘# type:
     ignore[E1000]’ will have the string ‘"[E1000]"’ stored in its AST
     node.

   - bpo-2180(18): Treat line continuation at EOF as a ‘SyntaxError’ by
     Anthony Sottile.

   - bpo-36907(19): Fix a crash when calling a C function with a keyword
     dict (‘f(**kwargs)’) and changing the dict ‘kwargs’ while that
     function is running.

   - bpo-36946(20): Fix possible signed integer overflow when handling
     slices.

   - bpo-36826(21): Add NamedExpression kind support to ast_unparse.c

   - bpo-1875(22): A *note SyntaxError: 18d. is now raised if a code
     blocks that will be optimized away (e.g.  if conditions that are
     always false) contains syntax errors.  Patch by Pablo Galindo.

   - bpo-36027(23): Allow computation of modular inverses via
     three-argument ‘pow’: the second argument is now permitted to be
     negative in the case where the first and third arguments are
     relatively prime.

   - bpo-36861(24): Update the Unicode database to version 12.1.0.

   - bpo-28866(25): Avoid caching attributes of classes which type
     defines mro() to avoid a hard cache invalidation problem.

   - bpo-36851(26): The ‘FrameType’ stack is now correctly cleaned up if
     the execution ends with a return and the stack is not empty.

   - bpo-34616(27): The ‘compile()’ builtin functions now support the
     ‘ast.PyCF_ALLOW_TOP_LEVEL_AWAIT’ flag, which allow to compile
     sources that contains top-level ‘await’, ‘async with’ or ‘async
     for’.  This is useful to evaluate async-code from with an already
     async functions; for example in a custom REPL.

   - bpo-36842(28): Implement PEP 578, adding sys.audit, io.open_code
     and related APIs.

   - bpo-27639(29): Correct return type for UserList slicing operations.
     Patch by Michael Blahay, Erick Cervantes, and vaultah

   - bpo-36737(30): Move PyRuntimeState.warnings into per-interpreter
     state (via “module state”).

   - bpo-36793(31): Removed ‘__str__’ implementations from builtin types
     *note bool: 46b, *note int: 257, *note float: 2f7, *note complex:
     2f8. and few classes from the standard library.  They now inherit
     ‘__str__()’ from *note object: a9b.

   - bpo-36817(32): Add a ‘=’ feature f-strings for debugging.  This can
     precede ‘!s’, ‘!r’, or ‘!a’.  It produces the text of the
     expression, followed by an equal sign, followed by the repr of the
     value of the expression.  So ‘f'{3*9+15=}'’ would be equal to the
     string ‘'3*9+15=42'’.  If ‘=’ is specified, the default conversion
     is set to ‘!r’, unless a format spec is given, in which case the
     formatting behavior is unchanged, and __format__ will be used.

   - bpo-24048(33): Save the live exception during import.c’s
     ‘remove_module()’.

   - bpo-27987(34): pymalloc returns memory blocks aligned by 16 bytes,
     instead of 8 bytes, on 64-bit platforms to conform x86-64 ABI.
     Recent compilers assume this alignment more often.  Patch by Inada
     Naoki.

   - bpo-36601(35): A long-since-meaningless check for ‘getpid() ==
     main_pid’ was removed from Python’s internal C signal handler.

   - bpo-36594(36): Fix incorrect use of ‘%p’ in format strings.  Patch
     by Zackery Spytz.

   - bpo-36045(37): ‘builtins.help()’ now prefixes ‘async’ for async
     functions.

   - bpo-36084(38): Add native thread ID (TID) to threading.Thread
     objects (supported platforms: Windows, FreeBSD, Linux, macOS)

   - bpo-36035(39): Added fix for broken symlinks in combination with
     pathlib

   - bpo-35983(40): Added new trashcan macros to deal with a double
     deallocation that could occur when the ‘tp_dealloc’ of a subclass
     calls the ‘tp_dealloc’ of a base class and that base class uses the
     trashcan mechanism.  Patch by Jeroen Demeyer.

   - bpo-20602(41): Do not clear *note sys.flags: 68f. and *note
     sys.float_info: 1b7b. during shutdown.  Patch by Zackery Spytz.

   - bpo-26826(42): Expose ‘copy_file_range()’ as a low level API in the
     *note os: a1. module.

   - bpo-32388(43): Remove cross-version binary compatibility
     requirement in tp_flags.

   - bpo-31862(44): Port binascii to PEP 489 multiphase initialization.
     Patch by Marcel Plch.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35814

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37126

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37122

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20092

   (5) https://bugs.python.org/issue?@action=redirect&bpo=37087

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26219

   (7) https://bugs.python.org/issue?@action=redirect&bpo=37072

   (8) https://bugs.python.org/issue?@action=redirect&bpo=37029

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26423

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37050

   (11) https://bugs.python.org/issue?@action=redirect&bpo=22385

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26836

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37032

   (14) https://bugs.python.org/issue?@action=redirect&bpo=37007

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36829

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36878

   (17) https://bugs.python.org/issue?@action=redirect&bpo=36878

   (18) https://bugs.python.org/issue?@action=redirect&bpo=2180

   (19) https://bugs.python.org/issue?@action=redirect&bpo=36907

   (20) https://bugs.python.org/issue?@action=redirect&bpo=36946

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36826

   (22) https://bugs.python.org/issue?@action=redirect&bpo=1875

   (23) https://bugs.python.org/issue?@action=redirect&bpo=36027

   (24) https://bugs.python.org/issue?@action=redirect&bpo=36861

   (25) https://bugs.python.org/issue?@action=redirect&bpo=28866

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36851

   (27) https://bugs.python.org/issue?@action=redirect&bpo=34616

   (28) https://bugs.python.org/issue?@action=redirect&bpo=36842

   (29) https://bugs.python.org/issue?@action=redirect&bpo=27639

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36737

   (31) https://bugs.python.org/issue?@action=redirect&bpo=36793

   (32) https://bugs.python.org/issue?@action=redirect&bpo=36817

   (33) https://bugs.python.org/issue?@action=redirect&bpo=24048

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27987

   (35) https://bugs.python.org/issue?@action=redirect&bpo=36601

   (36) https://bugs.python.org/issue?@action=redirect&bpo=36594

   (37) https://bugs.python.org/issue?@action=redirect&bpo=36045

   (38) https://bugs.python.org/issue?@action=redirect&bpo=36084

   (39) https://bugs.python.org/issue?@action=redirect&bpo=36035

   (40) https://bugs.python.org/issue?@action=redirect&bpo=35983

   (41) https://bugs.python.org/issue?@action=redirect&bpo=20602

   (42) https://bugs.python.org/issue?@action=redirect&bpo=26826

   (43) https://bugs.python.org/issue?@action=redirect&bpo=32388

   (44) https://bugs.python.org/issue?@action=redirect&bpo=31862


File: python.info,  Node: Library<134>,  Next: Documentation<50>,  Prev: Core and Builtins<132>,  Up: Python 3 8 0 beta 1

1.23.59.3 Library
.................

   - bpo-37128(1): Added *note math.perm(): 6d4.

   - bpo-37120(2): Add SSLContext.num_tickets to control the number of
     TLSv1.3 session tickets.

   - bpo-12202(3): Fix the error handling in
     ‘msilib.SummaryInformation.GetProperty()’.  Patch by Zackery Spytz.

   - bpo-26835(4): The fcntl module now contains file sealing constants
     for sealing of memfds.

   - bpo-29262(5): Add ‘get_origin()’ and ‘get_args()’ introspection
     helpers to ‘typing’ module.

   - bpo-12639(6): ‘msilib.Directory.start_component()’ no longer fails
     if 'keyfile' is not ‘None’.

   - bpo-36999(7): Add the ‘asyncio.Task.get_coro()’ method to publicly
     expose the tasks’s coroutine object.

   - bpo-35246(8): Make *note asyncio.create_subprocess_exec(): a86.
     accept path-like arguments.

   - bpo-35279(9): Change default 'max_workers' of ‘ThreadPoolExecutor’
     from ‘cpu_count() * 5’ to ‘min(32, cpu_count() + 4)’.  Previous
     value was unreasonably large on many cores machines.

   - bpo-37076(10): *note _thread.start_new_thread(): 196. now logs
     uncaught exception raised by the function using *note
     sys.unraisablehook(): 1f7, rather than *note sys.excepthook(): 811,
     so the hook gets access to the function which raised the exception.

   - bpo-33725(11): On macOS, the *note multiprocessing: 94. module now
     uses 'spawn' start method by default.

   - bpo-37054(12): Fix destructor ‘_pyio.BytesIO’ and
     ‘_pyio.TextIOWrapper’: initialize their ‘_buffer’ attribute as soon
     as possible (in the class body), because it’s used by ‘__del__()’
     which calls ‘close()’.

   - bpo-37058(13): PEP 544: Add ‘Protocol’ and ‘@runtime_checkable’ to
     the ‘typing’ module.

   - bpo-36933(14): The functions ‘sys.set_coroutine_wrapper’ and
     ‘sys.get_coroutine_wrapper’ that were deprecated and marked for
     removal in 3.8 have been removed.

   - bpo-37047(15): Handle late binding and attribute access in *note
     unittest.mock.AsyncMock: a57. setup for autospeccing.  Document
     newly implemented async methods in *note unittest.mock.MagicMock:
     ec3.

   - bpo-37049(16): PEP 589: Add ‘TypedDict’ to the ‘typing’ module.

   - bpo-37046(17): PEP 586: Add ‘Literal’ to the ‘typing’ module.

   - bpo-37045(18): PEP 591: Add ‘Final’ qualifier and ‘@final’
     decorator to the ‘typing’ module.

   - bpo-37035(19): Don’t log OSError based exceptions if a fatal error
     has occurred in asyncio transport.  Peer can generate almost any
     OSError, user cannot avoid these exceptions by fixing own code.
     Errors are still propagated to user code, it’s just logging them is
     pointless and pollute asyncio logs.

   - bpo-37001(20): *note symtable.symtable(): 1b7d. now accepts the
     same input types for source code as the built-in *note compile():
     192. function.  Patch by Dino Viehland.

   - bpo-37028(21): Implement asyncio REPL

   - bpo-37027(22): Return safe to use proxy socket object from
     transport.get_extra_info(‘socket’)

   - bpo-32528(23): Make asyncio.CancelledError a BaseException.

     This will address the common mistake many asyncio users make: an
     “except Exception” clause breaking Tasks cancellation.

     In addition to this change, we stop inheriting asyncio.TimeoutError
     and asyncio.InvalidStateError from their concurrent.futures.*
     counterparts.  There’s no point for these exceptions to share the
     inheritance chain.

   - bpo-1230540(24): Add a new *note threading.excepthook(): 851.
     function which handles uncaught *note threading.Thread.run(): a4a.
     exception.  It can be overridden to control how uncaught
     ‘threading.Thread.run()’ exceptions are handled.

   - bpo-36996(25): Handle *note unittest.mock.patch(): ec6. used as a
     decorator on async functions.

   - bpo-37008(26): Add support for calling *note next(): 7dc. with the
     mock resulting from *note unittest.mock.mock_open(): 1022.

   - bpo-27737(27): Allow whitespace only header encoding in
     ‘email.header’ - by Batuhan Taskaya

   - bpo-36969(28): PDB command ‘args’ now display positional only
     arguments.  Patch contributed by Rémi Lapeyre.

   - bpo-36969(29): PDB command ‘args’ now display keyword only
     arguments.  Patch contributed by Rémi Lapeyre.

   - bpo-36983(30): Add missing names to ‘typing.__all__’: ‘ChainMap’,
     ‘ForwardRef’, ‘OrderedDict’ - by Anthony Sottile.

   - bpo-36972(31): Add SupportsIndex protocol to the typing module to
     allow type checking to detect classes that can be passed to
     ‘hex()’, ‘oct()’ and ‘bin()’.

   - bpo-32972(32): Implement ‘unittest.IsolatedAsyncioTestCase’ to help
     testing asyncio-based code.

   - bpo-36952(33): *note fileinput.input(): 805. and *note
     fileinput.FileInput: 73a. 'bufsize' argument has been removed (was
     deprecated and ignored since Python 3.6), and as a result the
     'mode' and 'openhook' arguments have been made keyword-only.

   - bpo-36952(34): Starting with Python 3.3, importing ABCs from *note
     collections: 1d. is deprecated, and import should be done from
     *note collections.abc: 1e.  Still being able to import from
     ‘collections’ was marked for removal in 3.8, but has been delayed
     to 3.9; documentation and ‘DeprecationWarning’ clarified.

   - bpo-36949(35): Implement __repr__ for WeakSet objects.

   - bpo-36948(36): Fix *note NameError: 442. in *note
     urllib.request.URLopener.retrieve(): 1b7e.  Patch by Karthikeyan
     Singaravelan.

   - bpo-33524(37): Fix the folding of email header when the
     max_line_length is 0 or None and the header contains non-ascii
     characters.  Contributed by Licht Takeuchi (@Licht-T).

   - bpo-24564(38): *note shutil.copystat(): 1172. now ignores *note
     errno.EINVAL: 1b7f. on *note os.setxattr(): 114b. which may occur
     when copying files on filesystems without extended attributes
     support.

     Original patch by Giampaolo Rodola, updated by Ying Wang.

   - bpo-36888(39): Python child processes can now access the status of
     their parent process using multiprocessing.process.parent_process

   - bpo-36921(40): Deprecate ‘@coroutine’ for sake of ‘async def’.

   - bpo-25652(41): Fix bug in ‘__rmod__’ of ‘UserString’ - by Batuhan
     Taskaya.

   - bpo-36916(42): Remove a message about an unhandled exception in a
     task when writer.write() is used without await and writer.drain()
     fails with an exception.

   - bpo-36889(43): Introduce ‘asyncio.Stream’ class that merges *note
     asyncio.StreamReader: 15b6. and *note asyncio.StreamWriter: 180f.
     functionality.  ‘asyncio.Stream’ can work in readonly, writeonly
     and readwrite modes.  Provide ‘asyncio.connect()’,
     ‘asyncio.connect_unix()’, ‘asyncio.connect_read_pipe()’ and
     ‘asyncio.connect_write_pipe()’ factories to open ‘asyncio.Stream’
     connections.  Provide ‘asyncio.StreamServer’ and ‘UnixStreamServer’
     to serve servers with asyncio.Stream API. Modify *note
     asyncio.create_subprocess_shell(): a87. and *note
     asyncio.create_subprocess_exec(): a86. to use ‘asyncio.Stream’
     instead of deprecated ‘StreamReader’ and ‘StreamWriter’.  Deprecate
     ‘asyncio.StreamReader’ and ‘asyncio.StreamWriter’.  Deprecate usage
     of private classes, e.g.  ‘asyncio.FlowControlMixing’ and
     ‘asyncio.StreamReaderProtocol’ outside of asyncio package.

   - bpo-36845(44): Added validation of integer prefixes to the
     construction of IP networks and interfaces in the ipaddress module.

   - bpo-23378(45): Add an extend action to argparser.

   - bpo-36867(46): Fix a bug making a SharedMemoryManager instance and
     its parent process use two separate resource_tracker processes.

   - bpo-23896(47): Adds a grammar to lib2to3.pygram that contains exec
     as a function not as statement.

   - bpo-36895(48): The function ‘time.clock()’ was deprecated in 3.3 in
     favor of ‘time.perf_counter()’ and marked for removal in 3.8, it
     has removed.

   - bpo-35545(49): Fix asyncio discarding IPv6 scopes when ensuring
     hostname resolutions internally

   - bpo-36887(50): Add new function *note math.isqrt(): a10. to compute
     integer square roots.

   - bpo-34632(51): Introduce the ‘importlib.metadata’ module with
     (provisional) support for reading metadata from third-party
     packages.

   - bpo-36878(52): When using ‘type_comments=True’ in ‘ast.parse’,
     treat ‘# type: ignore’ followed by a non-alphanumeric character and
     then arbitrary text as a type ignore, instead of requiring nothing
     but whitespace or another comment.  This is to permit formations
     such as ‘# type: ignore[E1000]’.

   - bpo-36778(53): ‘cp65001’ encoding (Windows code page 65001) becomes
     an alias to ‘utf_8’ encoding.

   - bpo-36867(54): The multiprocessing.resource_tracker replaces the
     multiprocessing.semaphore_tracker module.  Other than semaphores,
     resource_tracker also tracks shared_memory segments.

   - bpo-30262(55): The ‘Cache’ and ‘Statement’ objects of the *note
     sqlite3: cf. module are not exposed to the user.  Patch by Aviv
     Palivoda.

   - bpo-24538(56): In ‘shutil.copystat()’, first copy extended file
     attributes and then file permissions, since extended attributes can
     only be set on the destination while it is still writeable.

   - bpo-36829(57): Add new *note sys.unraisablehook(): 1f7. function
     which can be overridden to control how “unraisable exceptions” are
     handled.  It is called when an exception has occurred but there is
     no way for Python to handle it.  For example, when a destructor
     raises an exception or during garbage collection (*note
     gc.collect(): a47.).

   - bpo-36832(58): Introducing ‘zipfile.Path’, a pathlib-compatible
     wrapper for traversing zip files.

   - bpo-36814(59): Fix an issue where os.posix_spawnp() would
     incorrectly raise a TypeError when file_actions is None.

   - bpo-33110(60): Handle exceptions raised by functions added by
     concurrent.futures add_done_callback correctly when the Future has
     already completed.

   - bpo-26903(61): Limit ‘max_workers’ in ‘ProcessPoolExecutor’ to 61
     to work around a WaitForMultipleObjects limitation.

   - bpo-36813(62): Fix *note QueueListener: e5f. to call
     ‘queue.task_done()’ upon stopping.  Patch by Bar Harel.

   - bpo-36806(63): Forbid creation of asyncio stream objects like
     StreamReader, StreamWriter, Process, and their protocols outside of
     asyncio package.

   - bpo-36802(64): Provide both sync and async calls for
     StreamWriter.write() and StreamWriter.close()

   - bpo-36801(65): Properly handle SSL connection closing in asyncio
     StreamWriter.drain() call.

   - bpo-36785(66): Implement PEP 574 (pickle protocol 5 with
     out-of-band buffers).

   - bpo-36772(67): functools.lru_cache() can now be used as a straight
     decorator in addition to its existing usage as a function that
     returns a decorator.

   - bpo-6584(68): Add a *note BadGzipFile: a02. exception to the *note
     gzip: 67. module.

   - bpo-36748(69): Optimized write buffering in C implementation of
     ‘TextIOWrapper’.  Writing ASCII string to ‘TextIOWrapper’ with
     ascii, latin1, or utf-8 encoding is about 20% faster.  Patch by
     Inada Naoki.

   - bpo-8138(70): Don’t mark ‘wsgiref.simple_server.SimpleServer’ as
     multi-threaded since ‘wsgiref.simple_server.WSGIServer’ is
     single-threaded.

   - bpo-22640(71): *note py_compile.compile(): a32. now supports silent
     mode.  Patch by Joannah Nanjekye

   - bpo-29183(72): Fix double exceptions in *note
     wsgiref.handlers.BaseHandler: 1b80. by calling its ‘close()’ method
     only when no exception is raised.

   - bpo-36548(73): Improved the repr of regular expression flags.

   - bpo-36542(74): The signature of Python functions can now be
     overridden by specifying the ‘__text_signature__’ attribute.

   - bpo-36533(75): Reinitialize logging.Handler locks in forked child
     processes instead of attempting to acquire them all in the parent
     before forking only to be released in the child process.  The
     acquire/release pattern was leading to deadlocks in code that has
     implemented any form of chained logging handlers that depend upon
     one another as the lock acquisition order cannot be guaranteed.

   - bpo-35252(76): Throw a TypeError instead of an AssertionError when
     using an invalid type annotation with singledispatch.

   - bpo-35900(77): Allow reduction methods to return a 6-item tuple
     where the 6th item specifies a custom state-setting method that’s
     called instead of the regular ‘__setstate__’ method.

   - bpo-35900(78): enable custom reduction callback registration for
     functions and classes in _pickle.c, using the new Pickler’s
     attribute ‘reducer_override’

   - bpo-36368(79): Fix a bug crashing SharedMemoryManager instances in
     interactive sessions after a ctrl-c (KeyboardInterrupt) was sent

   - bpo-31904(80): Fix mmap fail for VxWorks

   - bpo-27497(81): *note csv.DictWriter.writeheader(): 1244. now
     returns the return value of the underlying ‘csv.Writer.writerow()’
     method.  Patch contributed by Ashish Nitin Patil.

   - bpo-36239(82): Parsing .mo files now ignores comments starting and
     ending with #-#-#-#-#.

   - bpo-26707(83): Enable plistlib to read and write binary plist files
     that were created as a KeyedArchive file.  Specifically, this
     allows the plistlib to process 0x80 tokens as UID objects.

   - bpo-31904(84): Add posix module support for VxWorks.

   - bpo-35125(85): Asyncio: Remove inner callback on outer cancellation
     in shield

   - bpo-35721(86): Fix ‘asyncio.SelectorEventLoop.subprocess_exec()’
     leaks file descriptors if ‘Popen’ fails and called with
     ‘stdin=subprocess.PIPE’.  Patch by Niklas Fiekas.

   - bpo-31855(87): *note unittest.mock.mock_open(): 1022. results now
     respects the argument of read([size]).  Patch contributed by Rémi
     Lapeyre.

   - bpo-35431(88): Implement *note math.comb(): 6d3. that returns
     binomial coefficient, that computes the number of ways to choose k
     items from n items without repetition and without order.  Patch by
     Yash Aggarwal and Keller Fuchs.

   - bpo-26660(89): Fixed permission errors in *note TemporaryDirectory:
     127a. clean up.  Previously ‘TemporaryDirectory.cleanup()’ failed
     when non-writeable or non-searchable files or directories were
     created inside a temporary directory.

   - bpo-34271(90): Add debugging helpers to ssl module.  It’s now
     possible to dump key material and to trace TLS protocol.  The
     default and stdlib contexts also support SSLKEYLOGFILE env var.

   - bpo-26467(91): Added AsyncMock to support using unittest to mock
     asyncio coroutines.  Patch by Lisa Roach.

   - bpo-33569(92): dataclasses.InitVar: Exposes the type used to create
     the init var.

   - bpo-34424(93): Fix serialization of messages containing encoded
     strings when the policy.linesep is set to a multi-character string.
     Patch by Jens Troeger.

   - bpo-34303(94): Performance of *note functools.reduce(): 1324. is
     slightly improved.  Patch by Sergey Fedoseev.

   - bpo-33361(95): Fix a bug in *note codecs.StreamRecoder: 1b81. where
     seeking might leave old data in a buffer and break subsequent read
     calls.  Patch by Ammar Askar.

   - bpo-22454(96): The *note shlex: c4. module now exposes *note
     shlex.join(): a34, the inverse of *note shlex.split(): 53f.  Patch
     by Bo Bayles.

   - bpo-31922(97):
     ‘asyncio.AbstractEventLoop.create_datagram_endpoint()’: Do not
     connect UDP socket when broadcast is allowed.  This allows to
     receive replies after a UDP broadcast.

   - bpo-24882(98): Change ThreadPoolExecutor to use existing idle
     threads before spinning up new ones.

   - bpo-31961(99): Added support for bytes and path-like objects in
     *note subprocess.Popen(): 199. on Windows.  The 'args' parameter
     now accepts a *note path-like object: 2a0. if 'shell' is ‘False’
     and a sequence containing bytes and path-like objects.  The
     'executable' parameter now accepts a bytes and path-like object.
     The 'cwd' parameter now accepts a bytes object.  Based on patch by
     Anders Lorentsen.

   - bpo-33123(100): *note pathlib.Path.unlink: 1b82. now accepts a
     'missing_ok' parameter to avoid a *note FileNotFoundError: 42e.
     from being raised.  Patch by Robert Buchholz.

   - bpo-32941(101): Allow *note mmap.mmap: 20b. objects to access the
     madvise() system call (through *note mmap.mmap.madvise(): a13.).

   - bpo-22102(102): Added support for ZIP files with disks set to 0.
     Such files are commonly created by builtin tools on Windows when
     use ZIP64 extension.  Patch by Francisco Facioni.

   - bpo-32515(103): trace.py can now run modules via python3 -m trace
     -t –module module_name

   - bpo-32299(104): Changed *note unittest.mock.patch.dict(): 1b83. to
     return the patched dictionary when used as context manager.  Patch
     by Vadim Tsander.

   - bpo-27141(105): Added a ‘__copy__()’ to ‘collections.UserList’ and
     ‘collections.UserDict’ in order to correctly implement shallow
     copying of the objects.  Patch by Bar Harel.

   - bpo-31829(106): ‘\r’, ‘\0’ and ‘\x1a’ (end-of-file on Windows) are
     now escaped in protocol 0 pickles of Unicode strings.  This allows
     to load them without loss from files open in text mode in Python 2.

   - bpo-23395(107): ‘_thread.interrupt_main()’ now avoids setting the
     Python error status if the ‘SIGINT’ signal is ignored or not
     handled by Python.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37128

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37120

   (3) https://bugs.python.org/issue?@action=redirect&bpo=12202

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26835

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29262

   (6) https://bugs.python.org/issue?@action=redirect&bpo=12639

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36999

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35246

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35279

   (10) https://bugs.python.org/issue?@action=redirect&bpo=37076

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33725

   (12) https://bugs.python.org/issue?@action=redirect&bpo=37054

   (13) https://bugs.python.org/issue?@action=redirect&bpo=37058

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36933

   (15) https://bugs.python.org/issue?@action=redirect&bpo=37047

   (16) https://bugs.python.org/issue?@action=redirect&bpo=37049

   (17) https://bugs.python.org/issue?@action=redirect&bpo=37046

   (18) https://bugs.python.org/issue?@action=redirect&bpo=37045

   (19) https://bugs.python.org/issue?@action=redirect&bpo=37035

   (20) https://bugs.python.org/issue?@action=redirect&bpo=37001

   (21) https://bugs.python.org/issue?@action=redirect&bpo=37028

   (22) https://bugs.python.org/issue?@action=redirect&bpo=37027

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32528

   (24) https://bugs.python.org/issue?@action=redirect&bpo=1230540

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36996

   (26) https://bugs.python.org/issue?@action=redirect&bpo=37008

   (27) https://bugs.python.org/issue?@action=redirect&bpo=27737

   (28) https://bugs.python.org/issue?@action=redirect&bpo=36969

   (29) https://bugs.python.org/issue?@action=redirect&bpo=36969

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36983

   (31) https://bugs.python.org/issue?@action=redirect&bpo=36972

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32972

   (33) https://bugs.python.org/issue?@action=redirect&bpo=36952

   (34) https://bugs.python.org/issue?@action=redirect&bpo=36952

   (35) https://bugs.python.org/issue?@action=redirect&bpo=36949

   (36) https://bugs.python.org/issue?@action=redirect&bpo=36948

   (37) https://bugs.python.org/issue?@action=redirect&bpo=33524

   (38) https://bugs.python.org/issue?@action=redirect&bpo=24564

   (39) https://bugs.python.org/issue?@action=redirect&bpo=36888

   (40) https://bugs.python.org/issue?@action=redirect&bpo=36921

   (41) https://bugs.python.org/issue?@action=redirect&bpo=25652

   (42) https://bugs.python.org/issue?@action=redirect&bpo=36916

   (43) https://bugs.python.org/issue?@action=redirect&bpo=36889

   (44) https://bugs.python.org/issue?@action=redirect&bpo=36845

   (45) https://bugs.python.org/issue?@action=redirect&bpo=23378

   (46) https://bugs.python.org/issue?@action=redirect&bpo=36867

   (47) https://bugs.python.org/issue?@action=redirect&bpo=23896

   (48) https://bugs.python.org/issue?@action=redirect&bpo=36895

   (49) https://bugs.python.org/issue?@action=redirect&bpo=35545

   (50) https://bugs.python.org/issue?@action=redirect&bpo=36887

   (51) https://bugs.python.org/issue?@action=redirect&bpo=34632

   (52) https://bugs.python.org/issue?@action=redirect&bpo=36878

   (53) https://bugs.python.org/issue?@action=redirect&bpo=36778

   (54) https://bugs.python.org/issue?@action=redirect&bpo=36867

   (55) https://bugs.python.org/issue?@action=redirect&bpo=30262

   (56) https://bugs.python.org/issue?@action=redirect&bpo=24538

   (57) https://bugs.python.org/issue?@action=redirect&bpo=36829

   (58) https://bugs.python.org/issue?@action=redirect&bpo=36832

   (59) https://bugs.python.org/issue?@action=redirect&bpo=36814

   (60) https://bugs.python.org/issue?@action=redirect&bpo=33110

   (61) https://bugs.python.org/issue?@action=redirect&bpo=26903

   (62) https://bugs.python.org/issue?@action=redirect&bpo=36813

   (63) https://bugs.python.org/issue?@action=redirect&bpo=36806

   (64) https://bugs.python.org/issue?@action=redirect&bpo=36802

   (65) https://bugs.python.org/issue?@action=redirect&bpo=36801

   (66) https://bugs.python.org/issue?@action=redirect&bpo=36785

   (67) https://bugs.python.org/issue?@action=redirect&bpo=36772

   (68) https://bugs.python.org/issue?@action=redirect&bpo=6584

   (69) https://bugs.python.org/issue?@action=redirect&bpo=36748

   (70) https://bugs.python.org/issue?@action=redirect&bpo=8138

   (71) https://bugs.python.org/issue?@action=redirect&bpo=22640

   (72) https://bugs.python.org/issue?@action=redirect&bpo=29183

   (73) https://bugs.python.org/issue?@action=redirect&bpo=36548

   (74) https://bugs.python.org/issue?@action=redirect&bpo=36542

   (75) https://bugs.python.org/issue?@action=redirect&bpo=36533

   (76) https://bugs.python.org/issue?@action=redirect&bpo=35252

   (77) https://bugs.python.org/issue?@action=redirect&bpo=35900

   (78) https://bugs.python.org/issue?@action=redirect&bpo=35900

   (79) https://bugs.python.org/issue?@action=redirect&bpo=36368

   (80) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (81) https://bugs.python.org/issue?@action=redirect&bpo=27497

   (82) https://bugs.python.org/issue?@action=redirect&bpo=36239

   (83) https://bugs.python.org/issue?@action=redirect&bpo=26707

   (84) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (85) https://bugs.python.org/issue?@action=redirect&bpo=35125

   (86) https://bugs.python.org/issue?@action=redirect&bpo=35721

   (87) https://bugs.python.org/issue?@action=redirect&bpo=31855

   (88) https://bugs.python.org/issue?@action=redirect&bpo=35431

   (89) https://bugs.python.org/issue?@action=redirect&bpo=26660

   (90) https://bugs.python.org/issue?@action=redirect&bpo=34271

   (91) https://bugs.python.org/issue?@action=redirect&bpo=26467

   (92) https://bugs.python.org/issue?@action=redirect&bpo=33569

   (93) https://bugs.python.org/issue?@action=redirect&bpo=34424

   (94) https://bugs.python.org/issue?@action=redirect&bpo=34303

   (95) https://bugs.python.org/issue?@action=redirect&bpo=33361

   (96) https://bugs.python.org/issue?@action=redirect&bpo=22454

   (97) https://bugs.python.org/issue?@action=redirect&bpo=31922

   (98) https://bugs.python.org/issue?@action=redirect&bpo=24882

   (99) https://bugs.python.org/issue?@action=redirect&bpo=31961

   (100) https://bugs.python.org/issue?@action=redirect&bpo=33123

   (101) https://bugs.python.org/issue?@action=redirect&bpo=32941

   (102) https://bugs.python.org/issue?@action=redirect&bpo=22102

   (103) https://bugs.python.org/issue?@action=redirect&bpo=32515

   (104) https://bugs.python.org/issue?@action=redirect&bpo=32299

   (105) https://bugs.python.org/issue?@action=redirect&bpo=27141

   (106) https://bugs.python.org/issue?@action=redirect&bpo=31829

   (107) https://bugs.python.org/issue?@action=redirect&bpo=23395


File: python.info,  Node: Documentation<50>,  Next: Tests<52>,  Prev: Library<134>,  Up: Python 3 8 0 beta 1

1.23.59.4 Documentation
.......................

   - bpo-36896(1): Clarify that some types have unstable constructor
     signature between Python versions.

   - bpo-36686(2): Improve documentation of the stdin, stdout, and
     stderr arguments of the ‘asyncio.subprocess_exec’ function to
     specify which values are supported.  Also mention that decoding as
     text is not supported.

     Add a few tests to verify that the various values passed to the
     std* arguments actually work.

   - bpo-36984(3): Improve version added references in ‘typing’ module -
     by Anthony Sottile.

   - bpo-36868(4): What’s new now mentions
     SSLContext.hostname_checks_common_name instead of
     SSLContext.host_flags.

   - bpo-35924(5): Add a note to the ‘curses.addstr()’ documentation to
     warn that multiline strings can cause segfaults because of an
     ncurses bug.

   - bpo-36783(6): Added C API Documentation for Time_FromTimeAndFold
     and PyDateTime_FromDateAndTimeAndFold as per PEP 495.  Patch by
     Edison Abahurire.

   - bpo-36797(7): More of the legacy distutils documentation has been
     either pruned, or else more clearly marked as being retained solely
     until the setuptools documentation covers it independently.

   - bpo-22865(8): Add detail to the documentation on the ‘pty.spawn’
     function.

   - bpo-35397(9): Remove deprecation and document
     urllib.parse.unwrap().  Patch contributed by Rémi Lapeyre.

   - bpo-32995(10): Added the context variable in glossary.

   - bpo-33519(11): Clarify that ‘copy()’ is not part of the
     ‘MutableSequence’ ABC.

   - bpo-33482(12): Make ‘codecs.StreamRecoder.writelines’ take a list
     of bytes.

   - bpo-25735(13): Added documentation for func factorial to indicate
     that returns integer values

   - bpo-20285(14): Expand object.__doc__ (docstring) to make it
     clearer.  Modify pydoc.py so that help(object) lists object methods
     (for other classes, help omits methods of the object base class.)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36896

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36686

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36984

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36868

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35924

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36783

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36797

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22865

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35397

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32995

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33519

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33482

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25735

   (14) https://bugs.python.org/issue?@action=redirect&bpo=20285


File: python.info,  Node: Tests<52>,  Next: Build<57>,  Prev: Documentation<50>,  Up: Python 3 8 0 beta 1

1.23.59.5 Tests
...............

   - bpo-37069(1): Modify test_coroutines, test_cprofile,
     test_generators, test_raise, test_ssl and test_yield_from to use
     *note test.support.catch_unraisable_exception(): 1b68. rather than
     *note test.support.captured_stderr(): 1b86.

   - bpo-37098(2): Fix test_memfd_create on older Linux Kernels.

   - bpo-37081(3): Test with OpenSSL 1.1.1c

   - bpo-36829(4): Add *note test.support.catch_unraisable_exception():
     1b68.: context manager catching unraisable exception using *note
     sys.unraisablehook(): 1f7.

   - bpo-36915(5): The main regrtest process now always removes all
     temporary directories of worker processes even if they crash or if
     they are killed on KeyboardInterrupt (CTRL+c).

   - bpo-36719(6): “python3 -m test -jN …” now continues the execution
     of next tests when a worker process crash (CHILD_ERROR state).
     Previously, the test suite stopped immediately.  Use –failfast to
     stop at the first error.

   - bpo-36816(7): Update Lib/test/selfsigned_pythontestdotnet.pem to
     match self-signed.pythontest.net’s new TLS certificate.

   - bpo-35925(8): Skip httplib and nntplib networking tests when they
     would otherwise fail due to a modern OS or distro with a default
     OpenSSL policy of rejecting connections to servers with weak
     certificates.

   - bpo-36782(9): Add tests for several C API functions in the *note
     datetime: 30. module.  Patch by Edison Abahurire.

   - bpo-36342(10): Fix test_multiprocessing in test_venv if platform
     lacks functioning sem_open.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37069

   (2) https://bugs.python.org/issue?@action=redirect&bpo=37098

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37081

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36829

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36915

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36719

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36816

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35925

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36782

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36342


File: python.info,  Node: Build<57>,  Next: Windows<49>,  Prev: Tests<52>,  Up: Python 3 8 0 beta 1

1.23.59.6 Build
...............

   - bpo-36721(1): To embed Python into an application, a new ‘--embed’
     option must be passed to ‘python3-config --libs --embed’ to get
     ‘-lpython3.8’ (link the application to libpython).  To support both
     3.8 and older, try ‘python3-config --libs --embed’ first and
     fallback to ‘python3-config --libs’ (without ‘--embed’) if the
     previous command fails.

     Add a pkg-config ‘python-3.8-embed’ module to embed Python into an
     application: ‘pkg-config python-3.8-embed --libs’ includes
     ‘-lpython3.8’.  To support both 3.8 and older, try ‘pkg-config
     python-X.Y-embed --libs’ first and fallback to ‘pkg-config
     python-X.Y --libs’ (without ‘--embed’) if the previous command
     fails (replace ‘X.Y’ with the Python version).

     On the other hand, ‘pkg-config python3.8 --libs’ no longer contains
     ‘-lpython3.8’.  C extensions must not be linked to libpython
     (except on Android, case handled by the script); this change is
     backward incompatible on purpose.

   - bpo-36786(2): “make install” now runs compileall in parallel.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36721

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36786


File: python.info,  Node: Windows<49>,  Next: macOS<40>,  Prev: Build<57>,  Up: Python 3 8 0 beta 1

1.23.59.7 Windows
.................

   - bpo-36965(1): include of STATUS_CONTROL_C_EXIT without depending on
     MSC compiler

   - bpo-35926(2): Update to OpenSSL 1.1.1b for Windows.

   - bpo-29883(3): Add Windows support for UDP transports for the
     Proactor Event Loop.  Patch by Adam Meily.

   - bpo-33407(4): The *note Py_DEPRECATED(): ab9. macro has been
     implemented for MSVC.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36965

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35926

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29883

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33407


File: python.info,  Node: macOS<40>,  Next: IDLE<37>,  Prev: Windows<49>,  Up: Python 3 8 0 beta 1

1.23.59.8 macOS
...............

   - bpo-36231(1): Support building Python on macOS without /usr/include
     installed.  As of macOS 10.14, system header files are only
     available within an SDK provided by either the Command Line Tools
     or the Xcode app.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36231


File: python.info,  Node: IDLE<37>,  Next: Tools/Demos<27>,  Prev: macOS<40>,  Up: Python 3 8 0 beta 1

1.23.59.9 IDLE
..............

   - bpo-35610(1): Replace now redundant .context_use_ps1 with
     .prompt_last_line.  This finishes change started in bpo-31858(2).

   - bpo-37038(3): Make idlelib.run runnable; add test clause.

   - bpo-36958(4): Print any argument other than None or int passed to
     SystemExit or sys.exit().

   - bpo-36807(5): When saving a file, call os.fsync() so bits are
     flushed to e.g.  USB drive.

   - bpo-32411(6): In browser.py, remove extraneous sorting by line
     number since dictionary was created in line number order.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35610

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31858

   (3) https://bugs.python.org/issue?@action=redirect&bpo=37038

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36958

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36807

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32411


File: python.info,  Node: Tools/Demos<27>,  Next: C API<52>,  Prev: IDLE<37>,  Up: Python 3 8 0 beta 1

1.23.59.10 Tools/Demos
......................

   - bpo-37053(1): Handle strings like u”bar” correctly in
     Tools/parser/unparse.py.  Patch by Chih-Hsuan Yen.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=37053


File: python.info,  Node: C API<52>,  Prev: Tools/Demos<27>,  Up: Python 3 8 0 beta 1

1.23.59.11 C API
................

   - bpo-36763(1): Implement the PEP 587(2) “Python Initialization
     Configuration”.

   - bpo-36379(3): Fix crashes when attempting to use the 'modulo'
     parameter when ‘__ipow__’ is implemented in C.

   - bpo-37107(4): Update *note PyObject_CallMethodObjArgs(): 1b8d. and
     ‘_PyObject_CallMethodIdObjArgs’ to use ‘_PyObject_GetMethod’ to
     avoid creating a bound method object in many cases.  Patch by
     Michael J. Sullivan.

   - bpo-36974(5): Implement PEP 590(6): Vectorcall: a fast calling
     protocol for CPython.  This is a new protocol to optimize calls of
     custom callable objects.

   - bpo-36763(7): ‘Py_Main()’ now returns the exitcode rather than
     calling ‘Py_Exit(exitcode)’ when calling ‘PyErr_Print()’ if the
     current exception type is ‘SystemExit’.

   - bpo-36922(8): Add new type flag ‘Py_TPFLAGS_METHOD_DESCRIPTOR’ for
     objects behaving like unbound methods.  These are objects
     supporting the optimization given by the
     ‘LOAD_METHOD’/‘CALL_METHOD’ opcodes.  See PEP 590.

   - bpo-36728(9): The ‘PyEval_ReInitThreads()’ function has been
     removed from the C API. It should not be called explicitly: use
     *note PyOS_AfterFork_Child(): 3fe. instead.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36763

   (2) https://peps.python.org/pep-0587/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36379

   (4) https://bugs.python.org/issue?@action=redirect&bpo=37107

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36974

   (6) https://peps.python.org/pep-0590/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36763

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36922

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36728


File: python.info,  Node: Python 3 8 0 alpha 4,  Next: Python 3 8 0 alpha 3,  Prev: Python 3 8 0 beta 1,  Up: Changelog

1.23.60 Python 3.8.0 alpha 4
----------------------------

'Release date: 2019-05-06'

* Menu:

* Security: Security<41>.
* Core and Builtins: Core and Builtins<133>.
* Library: Library<135>.
* Documentation: Documentation<51>.
* Tests: Tests<53>.
* Build: Build<58>.
* Windows: Windows<50>.
* macOS: macOS<41>.
* IDLE: IDLE<38>.
* Tools/Demos: Tools/Demos<28>.
* C API: C API<53>.


File: python.info,  Node: Security<41>,  Next: Core and Builtins<133>,  Up: Python 3 8 0 alpha 4

1.23.60.1 Security
..................

   - bpo-36742(1): Fixes mishandling of pre-normalization characters in
     urlsplit().

   - bpo-30458(2): Address CVE 2019-9740(3) by disallowing URL paths
     with embedded whitespace or control characters through into the
     underlying http client request.  Such potentially malicious header
     injection URLs now cause an http.client.InvalidURL exception to be
     raised.

   - bpo-35755(4): *note shutil.which(): 4b7. now uses
     ‘os.confstr("CS_PATH")’ if available and if the ‘PATH’ environment
     variable is not set.  Remove also the current directory from
     ‘posixpath.defpath’.  On Unix, ‘shutil.which()’ and the *note
     subprocess: d6. module no longer search the executable in the
     current directory if the ‘PATH’ environment variable is not set.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36742

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30458

   (3) https://www.cve.org/CVERecord?id=CVE-2019-9740

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35755


File: python.info,  Node: Core and Builtins<133>,  Next: Library<135>,  Prev: Security<41>,  Up: Python 3 8 0 alpha 4

1.23.60.2 Core and Builtins
...........................

   - bpo-36722(1): In debug build, import now also looks for C
     extensions compiled in release mode and for C extensions compiled
     in the stable ABI.

   - bpo-32849(2): Fix Python Initialization code on FreeBSD to detect
     properly when stdin file descriptor (fd 0) is invalid.

   - bpo-36623(3): Remove parser headers and related function
     declarations that lack implementations after the removal of pgen.

   - bpo-20180(4): ‘dict.pop()’ is now up to 33% faster thanks to
     Argument Clinic.  Patch by Inada Naoki.

   - bpo-36611(5): Debug memory allocators: disable serialno field by
     default from debug hooks on Python memory allocators to reduce the
     memory footprint by 5%.  Enable *note tracemalloc: ff. to get the
     traceback where a memory block has been allocated when a fatal
     memory error is logged to decide where to put a breakpoint.
     Compile Python with ‘PYMEM_DEBUG_SERIALNO’ defined to get back the
     field.

   - bpo-36588(6): On AIX, *note sys.platform: a9c. doesn’t contain the
     major version anymore.  Always return ‘'aix'’, instead of ‘'aix3'’
     ..  ‘'aix7'’.  Since older Python versions include the version
     number, it is recommended to always use
     ‘sys.platform.startswith('aix')’.  Contributed by M. Felt.

   - bpo-36549(7): Change str.capitalize to use titlecase for the first
     character instead of uppercase.

   - bpo-36540(8): Implement PEP 570(9) (Python positional-only
     parameters).  Patch by Pablo Galindo.

   - bpo-36475(10): ‘PyEval_AcquireLock()’ and ‘PyEval_AcquireThread()’
     now terminate the current thread if called while the interpreter is
     finalizing, making them consistent with *note
     PyEval_RestoreThread(): 3ac, *note Py_END_ALLOW_THREADS(): a9d, and
     *note PyGILState_Ensure(): 3ae.

   - bpo-36504(11): Fix signed integer overflow in _ctypes.c’s
     ‘PyCArrayType_new()’.

   - bpo-20844(12): Fix running script with encoding cookie and LF line
     ending may fail on Windows.

   - bpo-24214(13): Fixed support of the surrogatepass error handler in
     the UTF-8 incremental decoder.

   - bpo-36452(14): Changing ‘dict’ keys during iteration of the dict
     itself, ‘keys()’, ‘values()’, or ‘items()’ will now be detected in
     certain corner cases where keys are deleted/added so that the
     number of keys isn’t changed.  A ‘RuntimeError’ will be raised
     after ‘len(dict)’ iterations.  Contributed by Thomas Perl.

   - bpo-36459(15): Fix a possible double ‘PyMem_FREE()’ due to
     tokenizer.c’s ‘tok_nextc()’.

   - bpo-36433(16): Fixed TypeError message in classmethoddescr_call.

   - bpo-36430(17): Fix a possible reference leak in *note
     itertools.count(): 12ca.

   - bpo-36440(18): Include node names in ‘ParserError’ messages,
     instead of numeric IDs.  Patch by A. Skrobov.

   - bpo-36143(19): Regenerate *note keyword: 84. from the Grammar and
     Tokens file using pgen.  Patch by Pablo Galindo.

   - bpo-18372(20): Add missing *note PyObject_GC_Track(): 1554. calls
     in the *note pickle: a6. module.  Patch by Zackery Spytz.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36722

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32849

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36623

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20180

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36611

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36588

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36549

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36540

   (9) https://peps.python.org/pep-0570/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36475

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36504

   (12) https://bugs.python.org/issue?@action=redirect&bpo=20844

   (13) https://bugs.python.org/issue?@action=redirect&bpo=24214

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36452

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36459

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36433

   (17) https://bugs.python.org/issue?@action=redirect&bpo=36430

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36440

   (19) https://bugs.python.org/issue?@action=redirect&bpo=36143

   (20) https://bugs.python.org/issue?@action=redirect&bpo=18372


File: python.info,  Node: Library<135>,  Next: Documentation<51>,  Prev: Core and Builtins<133>,  Up: Python 3 8 0 alpha 4

1.23.60.3 Library
.................

   - bpo-35952(1): Fix pythoninfo when the compiler is missing.

   - bpo-28238(2): The ‘.find*()’ methods of xml.etree.ElementTree can
     now search for wildcards like ‘{*}tag’ and ‘{ns}*’ that match a tag
     in any namespace or all tags in a namespace.  Patch by Stefan
     Behnel.

   - bpo-26978(3): ‘pathlib.path.link_to()’ is now implemented.  It
     creates a hard link pointing to a path.

   - bpo-1613500(4): *note fileinput.FileInput: 73a. now uses the input
     file mode to correctly set the output file mode (previously it was
     hardcoded to ‘'w'’) when ‘inplace=True’ is passed to its
     constructor.

   - bpo-36734(5): Fix compilation of ‘faulthandler.c’ on HP-UX.
     Initialize ‘stack_t current_stack’ to zero using ‘memset()’.

   - bpo-13611(6): The xml.etree.ElementTree packages gained support for
     C14N 2.0 serialisation.  Patch by Stefan Behnel.

   - bpo-36669(7): Add missing matrix multiplication operator support to
     weakref.proxy.

   - bpo-36676(8): The XMLParser() in xml.etree.ElementTree provides
     namespace prefix context to the parser target if it defines the
     callback methods “start_ns()” and/or “end_ns()”.  Patch by Stefan
     Behnel.

   - bpo-36673(9): The TreeBuilder and XMLPullParser in
     xml.etree.ElementTree gained support for parsing comments and
     processing instructions.  Patch by Stefan Behnel.

   - bpo-36650(10): The C version of functools.lru_cache() was treating
     calls with an empty ‘**kwargs’ dictionary as being distinct from
     calls with no keywords at all.  This did not result in an incorrect
     answer, but it did trigger an unexpected cache miss.

   - bpo-28552(11): Fix ‘distutils.sysconfig’ if *note sys.executable:
     3bb. is ‘None’ or an empty string: use *note os.getcwd(): 16a1. to
     initialize ‘project_base’.  Fix also the distutils build command:
     don’t use ‘sys.executable’ if it is ‘None’ or an empty string.

   - bpo-35755(12): *note shutil.which(): 4b7. and
     ‘distutils.spawn.find_executable’ now use ‘os.confstr("CS_PATH")’
     if available instead of *note os.defpath: 1b92, if the ‘PATH’
     environment variable is not set.  Moreover, don’t use
     ‘os.confstr("CS_PATH")’ nor ‘os.defpath’ if the ‘PATH’ environment
     variable is set to an empty string.

   - bpo-25430(13): improve performance of ‘IPNetwork.__contains__()’

   - bpo-30485(14): Path expressions in xml.etree.ElementTree can now
     avoid explicit namespace prefixes for tags (or the “{namespace}tag”
     notation) by passing a default namespace with an empty string
     prefix.

   - bpo-36613(15): Fix *note asyncio: a. wait() not removing callback
     if exception

   - bpo-36598(16): Fix ‘isinstance’ check for Mock objects with spec
     when the code is executed under tracing.  Patch by Karthikeyan
     Singaravelan.

   - bpo-18748(17): In development mode (*note -X: 176. ‘dev’) and in
     debug build, the *note io.IOBase: 1f5. destructor now logs
     ‘close()’ exceptions.  These exceptions are silent by default in
     release mode.

   - bpo-36575(18): The ‘_lsprof’ module now uses internal timer same to
     ‘time.perf_counter()’ by default.  ‘gettimeofday(2)’ was used on
     Unix.  New timer has better resolution on most Unix platforms and
     timings are no longer impacted by system clock updates since
     ‘perf_counter()’ is monotonic.  Patch by Inada Naoki.

   - bpo-33461(19): ‘json.loads’ now emits ‘DeprecationWarning’ when
     ‘encoding’ option is specified.  Patch by Matthias Bussonnier.

   - bpo-36559(20): The random module now prefers the lean internal
     _sha512 module over hashlib for seed(version=2) to optimize import
     time.

   - bpo-17561(21): Set backlog=None as the default for
     socket.create_server.

   - bpo-34373(22): Fix *note time.mktime(): 122d. error handling on AIX
     for year before 1970.

   - bpo-36232(23): Improve error message when trying to open existing
     DBM database that actually doesn’t exist.  Patch by Marco Rougeth.

   - bpo-36546(24): Add statistics.quantiles()

   - bpo-36050(25): Optimized ‘http.client.HTTPResponse.read()’ for
     large response.  Patch by Inada Naoki.

   - bpo-36522(26): If 'debuglevel' is set to >0 in *note http.client:
     6f, print all values for headers with multiple values for the same
     header name.  Patch by Matt Houglum.

   - bpo-36492(27): Deprecated passing required arguments like 'func' as
     keyword arguments in functions which should accept arbitrary
     keyword arguments and pass them to other function.  Arbitrary
     keyword arguments (even with names “self” and “func”) can now be
     passed to these functions if the required arguments are passed as
     positional arguments.

   - bpo-27181(28): Add statistics.geometric_mean().

   - bpo-30427(29): ‘os.path.normcase()’ relies on ‘os.fspath()’ to
     check the type of its argument.  Redundant checks have been removed
     from its ‘posixpath.normcase()’ and ‘ntpath.normcase()’
     implementations.  Patch by Wolfgang Maier.

   - bpo-36385(30): Stop rejecting IPv4 octets for being ambiguously
     octal.  Leading zeros are ignored, and no longer are assumed to
     specify octal octets.  Octets are always decimal numbers.  Octets
     must still be no more than three digits, including leading zeroes.

   - bpo-36434(31): Errors during writing to a ZIP file no longer
     prevent to properly close it.

   - bpo-36407(32): Fixed wrong indentation writing for CDATA section in
     xml.dom.minidom.  Patch by Vladimir Surjaninov.

   - bpo-36326(33): inspect.getdoc() can now find docstrings for member
     objects when __slots__ is a dictionary.

   - bpo-36366(34): Calling ‘stop()’ on an unstarted or stopped *note
     unittest.mock.patch(): ec6. object will now return ‘None’ instead
     of raising *note RuntimeError: 195, making the method idempotent.
     Patch by Karthikeyan Singaravelan.

   - bpo-36348(35): The ‘imap.IMAP4.logout()’ method no longer ignores
     silently arbitrary exceptions.

   - bpo-31904(36): Add time module support and fix test_time failures
     for VxWorks.

   - bpo-36227(37): Added support for keyword arguments
     ‘default_namespace’ and ‘xml_declaration’ in functions
     ‘ElementTree.tostring()’ and ‘ElementTree.tostringlist()’.

   - bpo-36004(38): Added new alternate constructors *note
     datetime.date.fromisocalendar(): 9f7. and *note
     datetime.datetime.fromisocalendar(): 9f8, which construct date
     objects from ISO year, week number and weekday; these are the
     inverse of each class’s ‘isocalendar’ method.  Patch by Paul
     Ganssle.

   - bpo-35936(39): *note modulefinder: 91. no longer depends on the
     deprecated *note imp: 76. module, and the initializer for *note
     modulefinder.ModuleFinder: 1b93. now has immutable default
     arguments.  Patch by Brandt Bucher.

   - bpo-35376(40): *note modulefinder: 91. correctly handles modules
     that have the same name as a bad package.  Patch by Brandt Bucher.

   - bpo-17396(41): *note modulefinder: 91. no longer crashes when
     encountering syntax errors in followed imports.  Patch by Brandt
     Bucher.

   - bpo-35934(42): Added *note create_server(): a38. and *note
     has_dualstack_ipv6(): a39. convenience functions to automate the
     necessary tasks usually involved when creating a server socket,
     including accepting both IPv4 and IPv6 connections on the same
     socket.  (Contributed by Giampaolo Rodola in bpo-17561(43).)

   - bpo-23078(44): Add support for *note classmethod(): 166. and *note
     staticmethod(): 419. to *note unittest.mock.create_autospec():
     1712.  Initial patch by Felipe Ochoa.

   - bpo-35416(45): Fix potential resource warnings in distutils.  Patch
     by Mickaël Schoentgen.

   - bpo-25451(46): Add transparency methods to ‘tkinter.PhotoImage’.
     Patch by Zackery Spytz.

   - bpo-35082(47): Don’t return deleted attributes when calling dir on
     a *note unittest.mock.Mock: a58.

   - bpo-34547(48): *note wsgiref.handlers.BaseHandler: 1b80. now
     handles abrupt client connection terminations gracefully.  Patch by
     Petter Strandmark.

   - bpo-31658(49): *note xml.sax.parse(): 1b94. now supports *note
     path-like: 2a0.  Patch by Mickaël Schoentgen.

   - bpo-34139(50): Remove stale unix datagram socket before binding

   - bpo-33530(51): Implemented Happy Eyeballs in
     ‘asyncio.create_connection()’.  Added two new arguments,
     'happy_eyeballs_delay' and 'interleave', to specify Happy Eyeballs
     behavior.

   - bpo-33291(52): Do not raise AttributeError when calling the inspect
     functions isgeneratorfunction, iscoroutinefunction,
     isasyncgenfunction on a method created from an arbitrary callable.
     Instead, return False.

   - bpo-31310(53): Fix the multiprocessing.semaphore_tracker so it is
     reused by child processes

   - bpo-31292(54): Fix ‘setup.py check --restructuredtext’ for files
     containing ‘include’ directives.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35952

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28238

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26978

   (4) https://bugs.python.org/issue?@action=redirect&bpo=1613500

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36734

   (6) https://bugs.python.org/issue?@action=redirect&bpo=13611

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36669

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36676

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36673

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36650

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28552

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35755

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25430

   (14) https://bugs.python.org/issue?@action=redirect&bpo=30485

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36613

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36598

   (17) https://bugs.python.org/issue?@action=redirect&bpo=18748

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36575

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33461

   (20) https://bugs.python.org/issue?@action=redirect&bpo=36559

   (21) https://bugs.python.org/issue?@action=redirect&bpo=17561

   (22) https://bugs.python.org/issue?@action=redirect&bpo=34373

   (23) https://bugs.python.org/issue?@action=redirect&bpo=36232

   (24) https://bugs.python.org/issue?@action=redirect&bpo=36546

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36050

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36522

   (27) https://bugs.python.org/issue?@action=redirect&bpo=36492

   (28) https://bugs.python.org/issue?@action=redirect&bpo=27181

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30427

   (30) https://bugs.python.org/issue?@action=redirect&bpo=36385

   (31) https://bugs.python.org/issue?@action=redirect&bpo=36434

   (32) https://bugs.python.org/issue?@action=redirect&bpo=36407

   (33) https://bugs.python.org/issue?@action=redirect&bpo=36326

   (34) https://bugs.python.org/issue?@action=redirect&bpo=36366

   (35) https://bugs.python.org/issue?@action=redirect&bpo=36348

   (36) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (37) https://bugs.python.org/issue?@action=redirect&bpo=36227

   (38) https://bugs.python.org/issue?@action=redirect&bpo=36004

   (39) https://bugs.python.org/issue?@action=redirect&bpo=35936

   (40) https://bugs.python.org/issue?@action=redirect&bpo=35376

   (41) https://bugs.python.org/issue?@action=redirect&bpo=17396

   (42) https://bugs.python.org/issue?@action=redirect&bpo=35934

   (43) https://bugs.python.org/issue?@action=redirect&bpo=17561

   (44) https://bugs.python.org/issue?@action=redirect&bpo=23078

   (45) https://bugs.python.org/issue?@action=redirect&bpo=35416

   (46) https://bugs.python.org/issue?@action=redirect&bpo=25451

   (47) https://bugs.python.org/issue?@action=redirect&bpo=35082

   (48) https://bugs.python.org/issue?@action=redirect&bpo=34547

   (49) https://bugs.python.org/issue?@action=redirect&bpo=31658

   (50) https://bugs.python.org/issue?@action=redirect&bpo=34139

   (51) https://bugs.python.org/issue?@action=redirect&bpo=33530

   (52) https://bugs.python.org/issue?@action=redirect&bpo=33291

   (53) https://bugs.python.org/issue?@action=redirect&bpo=31310

   (54) https://bugs.python.org/issue?@action=redirect&bpo=31292


File: python.info,  Node: Documentation<51>,  Next: Tests<53>,  Prev: Library<135>,  Up: Python 3 8 0 alpha 4

1.23.60.4 Documentation
.......................

   - bpo-36625(1): Remove obsolete comments from docstrings in
     fractions.Fraction

   - bpo-30840(2): Document relative imports

   - bpo-36523(3): Add docstring for io.IOBase.writelines().

   - bpo-36425(4): New documentation translation: Simplified Chinese(5).

   - bpo-36345(6): Avoid the duplication of code from
     ‘Tools/scripts/serve.py’ in using the ‘literalinclude’ directive
     for the basic wsgiref-based web server in the documentation of
     *note wsgiref: 118.  Contributed by Stéphane Wirtel.

   - bpo-36345(7): Using the code of the ‘Tools/scripts/serve.py’ script
     as an example in the *note wsgiref: 118. documentation.
     Contributed by Stéphane Wirtel.

   - bpo-36157(8): Added documentation for PyInterpreterState_Main().

   - bpo-33043(9): Updates the docs.python.org page with the addition of
     a ‘Contributing to Docs’ link at the end of the page (between
     ‘Reporting Bugs’ and ‘About Documentation’).  Updates the ‘Found a
     Bug’ page with additional links and information in the
     Documentation Bugs section.

   - bpo-35581(10): @typing.type_check_only now allows type stubs to
     mark functions and classes not available during runtime.

   - bpo-33832(11): Add glossary entry for ‘magic method’.

   - bpo-32913(12): Added re.Match.groupdict example to regex HOWTO.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36625

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30840

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36523

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36425

   (5) https://docs.python.org/zh-cn/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36345

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36345

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36157

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33043

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35581

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33832

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32913


File: python.info,  Node: Tests<53>,  Next: Build<58>,  Prev: Documentation<51>,  Up: Python 3 8 0 alpha 4

1.23.60.5 Tests
...............

   - bpo-36719(1): regrtest now always detects uncollectable objects.
     Previously, the check was only enabled by ‘--findleaks’.  The check
     now also works with ‘-jN/--multiprocess N’.  ‘--findleaks’ becomes
     a deprecated alias to ‘--fail-env-changed’.

   - bpo-36725(2): When using multiprocessing mode (-jN), regrtest now
     better reports errors if a worker process fails, and it exits
     immediately on a worker thread failure or when interrupted.

   - bpo-36454(3): Change test_time.test_monotonic() to test only the
     lower bound of elapsed time after a sleep command rather than the
     upper bound.  This prevents unnecessary test failures on slow
     buildbots.  Patch by Victor Stinner.

   - bpo-32424(4): Improve test coverage for xml.etree.ElementTree.
     Patch by Gordon P. Hemsley.

   - bpo-32424(5): Fix typo in test_cyclic_gc() test for
     xml.etree.ElementTree.  Patch by Gordon P. Hemsley.

   - bpo-36635(6): Add a new ‘_testinternalcapi’ module to test the
     internal C API.

   - bpo-36629(7): Fix ‘test_imap4_host_default_value()’ of
     ‘test_imaplib’: catch also *note errno.ENETUNREACH: 1b97. error.

   - bpo-36611(8): Fix ‘test_sys.test_getallocatedblocks()’ when *note
     tracemalloc: ff. is enabled.

   - bpo-36560(9): Fix reference leak hunting in regrtest: compute also
     deltas (of reference count, allocated memory blocks, file
     descriptor count) during warmup, to ensure that everything is
     initialized before starting to hunt reference leaks.

   - bpo-36565(10): Fix reference hunting (‘python3 -m test -R 3:3’)
     when Python has no built-in abc module.

   - bpo-31904(11): Port test_resource to VxWorks: skip tests cases
     setting RLIMIT_FSIZE and RLIMIT_CPU.

   - bpo-31904(12): Fix test_tabnanny on VxWorks: adjust ENOENT error
     message.

   - bpo-36436(13): Fix ‘_testcapi.pymem_buffer_overflow()’: handle
     memory allocation failure.

   - bpo-31904(14): Fix test_utf8_mode on VxWorks: Python always use
     UTF-8 on VxWorks.

   - bpo-36341(15): Fix tests that may fail with PermissionError upon
     calling bind() on AF_UNIX sockets.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36719

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36725

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36454

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32424

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32424

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36635

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36629

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36611

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36560

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36565

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (13) https://bugs.python.org/issue?@action=redirect&bpo=36436

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36341


File: python.info,  Node: Build<58>,  Next: Windows<50>,  Prev: Tests<53>,  Up: Python 3 8 0 alpha 4

1.23.60.6 Build
...............

   - bpo-36747(1): Remove the stale scriptsinstall Makefile target.

   - bpo-21536(2): On Unix, C extensions are no longer linked to
     libpython except on Android and Cygwin.

     It is now possible for a statically linked Python to load a C
     extension built using a shared library Python.

     When Python is embedded, ‘libpython’ must not be loaded with
     ‘RTLD_LOCAL’, but ‘RTLD_GLOBAL’ instead.  Previously, using
     ‘RTLD_LOCAL’, it was already not possible to load C extensions
     which were not linked to ‘libpython’, such as C extensions of the
     standard library built by the ‘*shared*’ section of
     ‘Modules/Setup’.

     distutils, python-config and python-config.py have been modified.

   - bpo-36707(3): ‘./configure --with-pymalloc’ no longer adds the ‘m’
     flag to SOABI (sys.implementation.cache_tag).  Enabling or
     disabling pymalloc has no impact on the ABI.

   - bpo-36635(4): Change ‘PyAPI_FUNC(type)’, ‘PyAPI_DATA(type)’ and
     ‘PyMODINIT_FUNC’ macros of ‘pyport.h’ when ‘Py_BUILD_CORE_MODULE’
     is defined.  The ‘Py_BUILD_CORE_MODULE’ define must be now be used
     to build a C extension as a dynamic library accessing Python
     internals: export the ‘PyInit_XXX()’ function in DLL exports on
     Windows.

   - bpo-31904(5): Don’t build the ‘_crypt’ extension on VxWorks.

   - bpo-36618(6): Add ‘-fmax-type-align=8’ to CFLAGS when clang
     compiler is detected.  The pymalloc memory allocator aligns memory
     on 8 bytes.  On x86-64, clang expects alignment on 16 bytes by
     default and so uses MOVAPS instruction which can lead to
     segmentation fault.  Instruct clang that Python is limited to
     alignment on 8 bytes to use MOVUPS instruction instead: slower but
     don’t trigger a SIGSEGV if the memory is not aligned on 16 bytes.
     Sadly, the flag must be added to ‘CFLAGS’ and not just
     ‘CFLAGS_NODIST’, since third party C extensions can have the same
     issue.

   - bpo-36605(7): ‘make tags’ and ‘make TAGS’ now also parse
     ‘Modules/_io/*.c’ and ‘Modules/_io/*.h’.

   - bpo-36465(8): Release builds and debug builds are now ABI
     compatible: defining the ‘Py_DEBUG’ macro no longer implies the
     ‘Py_TRACE_REFS’ macro, which introduces the only ABI
     incompatibility.  The ‘Py_TRACE_REFS’ macro, which adds the *note
     sys.getobjects(): 42a. function and the *note PYTHONDUMPREFS: 9b1.
     environment variable, can be set using the new ‘./configure
     --with-trace-refs’ build option.

   - bpo-36577(9): setup.py now correctly reports missing OpenSSL
     headers and libraries again.

   - bpo-36544(10): Fix regression introduced in bpo-36146(11)
     refactoring setup.py

   - bpo-36508(12): ‘python-config --ldflags’ no longer includes flags
     of the ‘LINKFORSHARED’ variable.  The ‘LINKFORSHARED’ variable must
     only be used to build executables.

   - bpo-36503(13): Remove references to “aix3” and “aix4”.  Patch by M.
     Felt.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36747

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21536

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36707

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36635

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36618

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36605

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36465

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36577

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36544

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36146

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36508

   (13) https://bugs.python.org/issue?@action=redirect&bpo=36503


File: python.info,  Node: Windows<50>,  Next: macOS<41>,  Prev: Build<58>,  Up: Python 3 8 0 alpha 4

1.23.60.7 Windows
.................

   - bpo-35920(1): Added platform.win32_edition() and
     platform.win32_is_iot().  Added support for cross-compiling
     packages for Windows ARM32.  Skip tests that are not expected to
     work on Windows IoT Core ARM32.

   - bpo-36649(2): Remove trailing spaces for registry keys when
     installed via the Store.

   - bpo-34144(3): Fixed activate.bat to correctly update codepage when
     chcp.com returns dots in output.  Patch by Lorenz Mende.

   - bpo-36509(4): Added preset-iot layout for Windows IoT ARM
     containers.  This layout doesn’t contain UI components like tkinter
     or IDLE. It also doesn’t contain files to support on-target builds
     since Windows ARM32 builds must be cross-compiled when using MSVC.

   - bpo-35941(5): enum_certificates function of the ssl module now
     returns certificates from all available certificate stores inside
     windows in a query instead of returning only certificates from the
     system wide certificate store.  This includes certificates from
     these certificate stores: local machine, local machine enterprise,
     local machine group policy, current user, current user group
     policy, services, users.  ssl.enum_crls() function is changed in
     the same way to return all certificate revocation lists inside the
     windows certificate revocation list stores.

   - bpo-36441(6): Fixes creating a venv when debug binaries are
     installed.

   - bpo-36085(7): Enable better DLL resolution on Windows by using safe
     DLL search paths and adding *note os.add_dll_directory(): 9f5.

   - bpo-36010(8): Add the venv standard library module to the nuget
     distribution for Windows.

   - bpo-29515(9): Add the following socket module constants on Windows:
     IPPROTO_AH IPPROTO_CBT IPPROTO_DSTOPTS IPPROTO_EGP IPPROTO_ESP
     IPPROTO_FRAGMENT IPPROTO_GGP IPPROTO_HOPOPTS IPPROTO_ICLFXBM
     IPPROTO_ICMPV6 IPPROTO_IDP IPPROTO_IGMP IPPROTO_IGP IPPROTO_IPV4
     IPPROTO_IPV6 IPPROTO_L2TP IPPROTO_MAX IPPROTO_ND IPPROTO_NONE
     IPPROTO_PGM IPPROTO_PIM IPPROTO_PUP IPPROTO_RDP IPPROTO_ROUTING
     IPPROTO_SCTP IPPROTO_ST

   - bpo-35947(10): Added current version of libffi to
     cpython-source-deps.  Change _ctypes to use current version of
     libffi on Windows.

   - bpo-34060(11): Report system load when running test suite on
     Windows.  Patch by Ammar Askar.  Based on prior work by Jeremy
     Kloth.

   - bpo-31512(12): With the Windows 10 Creators Update, non-elevated
     users can now create symlinks as long as the computer has Developer
     Mode enabled.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35920

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34144

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36509

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35941

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36441

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36085

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36010

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29515

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35947

   (11) https://bugs.python.org/issue?@action=redirect&bpo=34060

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31512


File: python.info,  Node: macOS<41>,  Next: IDLE<38>,  Prev: Windows<50>,  Up: Python 3 8 0 alpha 4

1.23.60.8 macOS
...............

   - bpo-34602(1): Avoid failures setting macOS stack resource limit
     with resource.setrlimit.  This reverts an earlier fix for
     bpo-18075(2) which forced a non-default stack size when building
     the interpreter executable on macOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34602

   (2) https://bugs.python.org/issue?@action=redirect&bpo=18075


File: python.info,  Node: IDLE<38>,  Next: Tools/Demos<28>,  Prev: macOS<41>,  Up: Python 3 8 0 alpha 4

1.23.60.9 IDLE
..............

   - bpo-36429(1): Fix starting IDLE with pyshell.  Add idlelib.pyshell
     alias at top; remove pyshell alias at bottom.  Remove obsolete
     __name__==’__main__’ command.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36429


File: python.info,  Node: Tools/Demos<28>,  Next: C API<53>,  Prev: IDLE<38>,  Up: Python 3 8 0 alpha 4

1.23.60.10 Tools/Demos
......................

   - bpo-14546(1): Fix the argument handling in Tools/scripts/lll.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14546


File: python.info,  Node: C API<53>,  Prev: Tools/Demos<28>,  Up: Python 3 8 0 alpha 4

1.23.60.11 C API
................

   - bpo-36763(1): Fix memory leak in ‘Py_SetStandardStreamEncoding()’:
     release memory if the function is called twice.

   - bpo-36641(2): *note PyDoc_VAR: 1b9e.(name) and *note PyDoc_STRVAR:
     1b04.(name, str) now create ‘static const char name[]’ instead of
     ‘static char name[]’.  Patch by Inada Naoki.

   - bpo-36389(3): Change the value of ‘CLEANBYTE’, ‘DEADDYTE’ and
     ‘FORBIDDENBYTE’ internal constants used by debug hooks on Python
     memory allocators (*note PyMem_SetupDebugHooks(): c8b. function).
     Byte patterns ‘0xCB’, ‘0xDB’ and ‘0xFB’ have been replaced with
     ‘0xCD’, ‘0xDD’ and ‘0xFD’ to use the same values than Windows CRT
     debug ‘malloc()’ and ‘free()’.

   - bpo-36443(4): Since Python 3.7.0, calling *note Py_DecodeLocale():
     be6. before *note Py_Initialize(): 8b4. produces mojibake if the
     ‘LC_CTYPE’ locale is coerced and/or if the UTF-8 Mode is enabled by
     the user configuration.  The LC_CTYPE coercion and UTF-8 Mode are
     now disabled by default to fix the mojibake issue.  They must now
     be enabled explicitly (opt-in) using the new ‘_Py_PreInitialize()’
     API with ‘_PyPreConfig’.

   - bpo-36025(5): Fixed an accidental change to the datetime C API
     where the arguments to the *note PyDate_FromTimestamp(): 1b9f.
     function were incorrectly interpreted as a single timestamp rather
     than an arguments tuple, which causes existing code to start
     raising *note TypeError: 2c3.  The backwards-incompatible change
     was only present in alpha releases of Python 3.8.  Patch by Paul
     Ganssle.

   - bpo-35810(6): Modify ‘PyObject_Init’ to correctly increase the
     refcount of heap-allocated Type objects.  Also fix the refcounts of
     the heap-allocated types that were either doing this manually or
     not decreasing the type’s refcount in tp_dealloc

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36763

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36641

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36389

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36443

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36025

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35810


File: python.info,  Node: Python 3 8 0 alpha 3,  Next: Python 3 8 0 alpha 2,  Prev: Python 3 8 0 alpha 4,  Up: Changelog

1.23.61 Python 3.8.0 alpha 3
----------------------------

'Release date: 2019-03-25'

* Menu:

* Security: Security<42>.
* Core and Builtins: Core and Builtins<134>.
* Library: Library<136>.
* Documentation: Documentation<52>.
* Tests: Tests<54>.
* Build: Build<59>.
* Windows: Windows<51>.
* IDLE: IDLE<39>.
* Tools/Demos: Tools/Demos<29>.
* C API: C API<54>.


File: python.info,  Node: Security<42>,  Next: Core and Builtins<134>,  Up: Python 3 8 0 alpha 3

1.23.61.1 Security
..................

   - bpo-36216(1): Changes urlsplit() to raise ValueError when the URL
     contains characters that decompose under IDNA encoding
     (NFKC-normalization) into characters that affect how the URL is
     parsed.

   - bpo-35121(2): Don’t send cookies of domain A without Domain
     attribute to domain B when domain A is a suffix match of domain B
     while using a cookiejar with *note
     http.cookiejar.DefaultCookiePolicy: 1ba2. policy.  Patch by
     Karthikeyan Singaravelan.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36216

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35121


File: python.info,  Node: Core and Builtins<134>,  Next: Library<136>,  Prev: Security<42>,  Up: Python 3 8 0 alpha 3

1.23.61.2 Core and Builtins
...........................

   - bpo-36421(1): Fix a possible double decref in _ctypes.c’s
     ‘PyCArrayType_new()’.

   - bpo-36412(2): Fix a possible crash when creating a new dictionary.

   - bpo-36398(3): Fix a possible crash in ‘structseq_repr()’.

   - bpo-36256(4): Fix bug in parsermodule when parsing a state in a DFA
     that has two or more arcs with labels of the same type.  Patch by
     Pablo Galindo.

   - bpo-36365(5): repr(structseq) is no longer limited to 512 bytes.

   - bpo-36374(6): Fix a possible null pointer dereference in
     ‘merge_consts_recursive()’.  Patch by Zackery Spytz.

   - bpo-36236(7): At Python initialization, the current directory is no
     longer prepended to *note sys.path: 3b7. if it has been removed.

   - bpo-36352(8): Python initialization now fails with an error, rather
     than silently truncating paths, if a path is too long.

   - bpo-36301(9): Python initialization now fails if decoding
     ‘pybuilddir.txt’ configuration file fails at startup.

   - bpo-36333(10): Fix leak in _PyRuntimeState_Fini.  Contributed by
     Stéphane Wirtel.

   - bpo-36332(11): The builtin *note compile(): 192. can now handle AST
     objects that contain assignment expressions.  Patch by Pablo
     Galindo.

   - bpo-36282(12): Improved error message for too much positional
     arguments in some builtin functions.

   - bpo-30040(13): New empty dict uses fewer memory for now.  It used
     more memory than empty dict created by ‘dict.clear()’.  And empty
     dict creation and deletion is about 2x faster.  Patch by Inada
     Naoki.

   - bpo-36262(14): Fix an unlikely memory leak on conversion from
     string to float in the function ‘_Py_dg_strtod()’ used by
     ‘float(str)’, ‘complex(str)’, *note pickle.load(): d38, *note
     marshal.load(): 1ba4, etc.

   - bpo-36252(15): Update Unicode databases to version 12.0.0.

   - bpo-36218(16): Fix a segfault occurring when sorting a list of
     heterogeneous values.  Patch contributed by Rémi Lapeyre and Elliot
     Gorokhovsky.

   - bpo-36188(17): Cleaned up left-over vestiges of Python 2 unbound
     method handling in method objects and documentation.  Patch by
     Martijn Pieters

   - bpo-36124(18): Add a new interpreter-specific dict and expose it in
     the C-API via PyInterpreterState_GetDict().  This parallels
     PyThreadState_GetDict().  However, extension modules should
     continue using PyModule_GetState() for their own internal
     per-interpreter state.

   - bpo-35975(19): Add a ‘feature_version’ flag to ‘ast.parse()’
     (documented) and ‘compile()’ (hidden) that allows tweaking the
     parser to support older versions of the grammar.  In particular, if
     ‘feature_version’ is 5 or 6, the hacks for the ‘async’ and ‘await’
     keyword from PEP 492 are reinstated.  (For 7 or higher, these are
     unconditionally treated as keywords, but they are still special
     tokens rather than ‘NAME’ tokens that the parser driver
     recognizes.)

   - bpo-31904(20): Use UTF-8 as the system encoding on VxWorks.

   - bpo-36048(21): The *note __index__(): 720. special method will be
     used instead of *note __int__(): 71f. for implicit conversion of
     Python numbers to C integers.  Using the ‘__int__()’ method in
     implicit conversions has been deprecated.

   - bpo-35808(22): Retire pgen and use a modified version of pgen2 to
     generate the parser.  Patch by Pablo Galindo.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36421

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36412

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36398

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36256

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36365

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36374

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36236

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36352

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36301

   (10) https://bugs.python.org/issue?@action=redirect&bpo=36333

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36332

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36282

   (13) https://bugs.python.org/issue?@action=redirect&bpo=30040

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36262

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36252

   (16) https://bugs.python.org/issue?@action=redirect&bpo=36218

   (17) https://bugs.python.org/issue?@action=redirect&bpo=36188

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36124

   (19) https://bugs.python.org/issue?@action=redirect&bpo=35975

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36048

   (22) https://bugs.python.org/issue?@action=redirect&bpo=35808


File: python.info,  Node: Library<136>,  Next: Documentation<52>,  Prev: Core and Builtins<134>,  Up: Python 3 8 0 alpha 3

1.23.61.3 Library
.................

   - bpo-36401(1): The class documentation created by pydoc now has a
     separate section for readonly properties.

   - bpo-36320(2): The typing.NamedTuple() class has deprecated the
     _field_types attribute in favor of the __annotations__ attribute
     which carried the same information.  Also, both attributes were
     converted from OrderedDict to a regular dict.

   - bpo-34745(3): Fix *note asyncio: a. ssl memory issues caused by
     circular references

   - bpo-36324(4): Add method to statistics.NormalDist for computing the
     inverse cumulative normal distribution.

   - bpo-36321(5): collections.namedtuple() misspelled the name of an
     attribute.  To be consistent with typing.NamedTuple, the attribute
     name should have been “_field_defaults” instead of
     “_fields_defaults”.  For backwards compatibility, both spellings
     are now created.  The misspelled version may be removed in the
     future.

   - bpo-36297(6): “unicode_internal” codec is removed.  It was
     deprecated since Python 3.3.  Patch by Inada Naoki.

   - bpo-36298(7): Raise ModuleNotFoundError in pyclbr when a module
     can’t be found.  Thanks to ‘mental’ for the bug report.

   - bpo-36268(8): Switch the default format used for writing tars with
     *note tarfile: de. to the modern POSIX.1-2001 pax standard, from
     the vendor-specific GNU. Contributed by C.A.M. Gerlach.

   - bpo-36285(9): Fix integer overflows in the array module.  Patch by
     Stephan Hohe.

   - bpo-31904(10): Add _signal module support for VxWorks.

   - bpo-36272(11): *note logging: 87. does not silently ignore
     RecursionError anymore.  Patch contributed by Rémi Lapeyre.

   - bpo-36280(12): Add a kind field to ast.Constant.  It is ‘u’ if the
     literal has a ‘u’ prefix (i.e.  a Python 2 style unicode literal),
     else None.

   - bpo-35931(13): The *note pdb: a5. ‘debug’ command now gracefully
     handles all exceptions.

   - bpo-36251(14): Fix format strings used for stderrprinter and
     re.Match reprs.  Patch by Stephan Hohe.

   - bpo-36235(15): Fix ‘CFLAGS’ in ‘customize_compiler()’ of
     ‘distutils.sysconfig’: when the ‘CFLAGS’ environment variable is
     defined, don’t override ‘CFLAGS’ variable with the ‘OPT’ variable
     anymore.  Initial patch written by David Malcolm.

   - bpo-35807(16): Update ensurepip to install pip 19.0.3 and
     setuptools 40.8.0.

   - bpo-36139(17): Release GIL when closing *note mmap: 20b. objects.

   - bpo-36179(18): Fix two unlikely reference leaks in _hashopenssl.
     The leaks only occur in out-of-memory cases.

   - bpo-36169(19): Add overlap() method to statistics.NormalDist.
     Computes the overlapping coefficient for two normal distributions.

   - bpo-36103(20): Default buffer size used by ‘shutil.copyfileobj()’
     is changed from 16 KiB to 64 KiB on non-Windows platform to reduce
     system call overhead.  Contributed by Inada Naoki.

   - bpo-36130(21): Fix ‘pdb’ with ‘skip=...’ when stepping into a frame
     without a ‘__name__’ global.  Patch by Anthony Sottile.

   - bpo-35652(22): shutil.copytree(copy_function=…) erroneously pass
     DirEntry instead of a path string.

   - bpo-35178(23): Ensure custom *note warnings.formatwarning(): 1ba6.
     function can receive ‘line’ as positional argument.  Based on patch
     by Tashrif Billah.

   - bpo-36106(24): Resolve potential name clash with libm’s sinpi().
     Patch by Dmitrii Pasechnik.

   - bpo-36091(25): Clean up reference to async generator in Lib/types.
     Patch by Henry Chen.

   - bpo-36043(26): ‘FileCookieJar’ supports *note path-like object:
     2a0.  Contributed by Stéphane Wirtel

   - bpo-35899(27): Enum has been fixed to correctly handle empty
     strings and strings with non-Latin characters (ie.  ‘α’, ‘א’)
     without crashing.  Original patch contributed by Maxwell.  Assisted
     by Stéphane Wirtel.

   - bpo-21269(28): Add ‘args’ and ‘kwargs’ properties to mock call
     objects.  Contributed by Kumar Akshay.

   - bpo-30670(29): ‘pprint.pp’ has been added to pretty-print objects
     with dictionary keys being sorted with their insertion order by
     default.  Parameter 'sort_dicts' has been added to ‘pprint.pprint’,
     ‘pprint.pformat’ and ‘pprint.PrettyPrinter’.  Contributed by Rémi
     Lapeyre.

   - bpo-35843(30): Implement ‘__getitem__’ for ‘_NamespacePath’.  Patch
     by Anthony Sottile.

   - bpo-35802(31): Clean up code which checked presence of ‘os.stat’ /
     ‘os.lstat’ / ‘os.chmod’ which are always present.  Patch by Anthony
     Sottile.

   - bpo-35715(32): Librates the return value of a ProcessPoolExecutor
     _process_worker after it’s no longer needed to free memory

   - bpo-35493(33): Use *note multiprocessing.connection.wait(): 1123.
     instead of polling each 0.2 seconds for worker updates in
     ‘multiprocessing.Pool’.  Patch by Pablo Galindo.

   - bpo-35661(34): Store the venv prompt in pyvenv.cfg.

   - bpo-35121(35): Don’t set cookie for a request when the request path
     is a prefix match of the cookie’s path attribute but doesn’t end
     with “/”.  Patch by Karthikeyan Singaravelan.

   - bpo-21478(36): Calls to a child function created with *note
     unittest.mock.create_autospec(): 1712. should propagate to the
     parent.  Patch by Karthikeyan Singaravelan.

   - bpo-35198(37): Fix C++ extension compilation on AIX

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36401

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36320

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34745

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36324

   (5) https://bugs.python.org/issue?@action=redirect&bpo=36321

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36297

   (7) https://bugs.python.org/issue?@action=redirect&bpo=36298

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36268

   (9) https://bugs.python.org/issue?@action=redirect&bpo=36285

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31904

   (11) https://bugs.python.org/issue?@action=redirect&bpo=36272

   (12) https://bugs.python.org/issue?@action=redirect&bpo=36280

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35931

   (14) https://bugs.python.org/issue?@action=redirect&bpo=36251

   (15) https://bugs.python.org/issue?@action=redirect&bpo=36235

   (16) https://bugs.python.org/issue?@action=redirect&bpo=35807

   (17) https://bugs.python.org/issue?@action=redirect&bpo=36139

   (18) https://bugs.python.org/issue?@action=redirect&bpo=36179

   (19) https://bugs.python.org/issue?@action=redirect&bpo=36169

   (20) https://bugs.python.org/issue?@action=redirect&bpo=36103

   (21) https://bugs.python.org/issue?@action=redirect&bpo=36130

   (22) https://bugs.python.org/issue?@action=redirect&bpo=35652

   (23) https://bugs.python.org/issue?@action=redirect&bpo=35178

   (24) https://bugs.python.org/issue?@action=redirect&bpo=36106

   (25) https://bugs.python.org/issue?@action=redirect&bpo=36091

   (26) https://bugs.python.org/issue?@action=redirect&bpo=36043

   (27) https://bugs.python.org/issue?@action=redirect&bpo=35899

   (28) https://bugs.python.org/issue?@action=redirect&bpo=21269

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30670

   (30) https://bugs.python.org/issue?@action=redirect&bpo=35843

   (31) https://bugs.python.org/issue?@action=redirect&bpo=35802

   (32) https://bugs.python.org/issue?@action=redirect&bpo=35715

   (33) https://bugs.python.org/issue?@action=redirect&bpo=35493

   (34) https://bugs.python.org/issue?@action=redirect&bpo=35661

   (35) https://bugs.python.org/issue?@action=redirect&bpo=35121

   (36) https://bugs.python.org/issue?@action=redirect&bpo=21478

   (37) https://bugs.python.org/issue?@action=redirect&bpo=35198


File: python.info,  Node: Documentation<52>,  Next: Tests<54>,  Prev: Library<136>,  Up: Python 3 8 0 alpha 3

1.23.61.4 Documentation
.......................

   - bpo-36329(1): Declare the path of the Python binary for the usage
     of ‘Tools/scripts/serve.py’ when executing ‘make -C Doc/ serve’.
     Contributed by Stéphane Wirtel

   - bpo-36138(2): Improve documentation about converting
     datetime.timedelta to scalars.

   - bpo-21314(3): A new entry was added to the Core Language Section of
     the Programming FAQ, which explaines the usage of slash(/) in the
     signature of a function.  Patch by Lysandros Nikolaou

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36329

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36138

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21314


File: python.info,  Node: Tests<54>,  Next: Build<59>,  Prev: Documentation<52>,  Up: Python 3 8 0 alpha 3

1.23.61.5 Tests
...............

   - bpo-36234(1): test_posix.PosixUidGidTests: add tests for invalid
     uid/gid type (str).  Initial patch written by David Malcolm.

   - bpo-29571(2): Fix ‘test_re.test_locale_flag()’: use
     ‘locale.getpreferredencoding()’ rather than ‘locale.getlocale()’ to
     get the locale encoding.  With some locales, ‘locale.getlocale()’
     returns the wrong encoding.

   - bpo-36123(3): Fix race condition in test_socket.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36234

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29571

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36123


File: python.info,  Node: Build<59>,  Next: Windows<51>,  Prev: Tests<54>,  Up: Python 3 8 0 alpha 3

1.23.61.6 Build
...............

   - bpo-36356(1): Fix leaks that led to build failure when configured
     with address sanitizer.

   - bpo-36146(2): Add ‘TEST_EXTENSIONS’ constant to ‘setup.py’ to allow
     to not build test extensions like ‘_testcapi’.

   - bpo-36146(3): Fix setup.py on macOS: only add ‘/usr/include/ffi’ to
     include directories of _ctypes, not for all extensions.

   - bpo-31904(4): Enable build system to cross-build for VxWorks RTOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36356

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36146

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36146

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31904


File: python.info,  Node: Windows<51>,  Next: IDLE<39>,  Prev: Build<59>,  Up: Python 3 8 0 alpha 3

1.23.61.7 Windows
.................

   - bpo-36312(1): Fixed decoders for the following code pages: 50220,
     50221, 50222, 50225, 50227, 50229, 57002 through 57011, 65000 and
     42.

   - bpo-36264(2): Don’t honor POSIX ‘HOME’ in ‘os.path.expanduser’ on
     windows.  Patch by Anthony Sottile.

   - bpo-24643(3): Fix name collisions due to ‘#define timezone
     _timezone’ in PC/pyconfig.h.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36312

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36264

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24643


File: python.info,  Node: IDLE<39>,  Next: Tools/Demos<29>,  Prev: Windows<51>,  Up: Python 3 8 0 alpha 3

1.23.61.8 IDLE
..............

   - bpo-36405(1): Use dict unpacking in idlelib.

   - bpo-36396(2): Remove fgBg param of idlelib.config.GetHighlight().
     This param was only used twice and changed the return type.

   - bpo-36176(3): Fix IDLE autocomplete & calltip popup colors.
     Prevent conflicts with Linux dark themes (and slightly darken
     calltip background).

   - bpo-23205(4): For the grep module, add tests for findfiles,
     refactor findfiles to be a module-level function, and refactor
     findfiles to use os.walk.

   - bpo-23216(5): Add docstrings to IDLE search modules.

   - bpo-36152(6): Remove colorizer.ColorDelegator.close_when_done and
     the corresponding argument of .close().  In IDLE, both have always
     been None or False since 2007.

   - bpo-32129(7): Avoid blurry IDLE application icon on macOS with Tk
     8.6.  Patch by Kevin Walzer.

   - bpo-36096(8): Refactor class variables to instance variables in
     colorizer.

   - bpo-30348(9): Increase test coverage of idlelib.autocomplete by
     30%.  Patch by Louie Lu

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36405

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36396

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36176

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23205

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23216

   (6) https://bugs.python.org/issue?@action=redirect&bpo=36152

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32129

   (8) https://bugs.python.org/issue?@action=redirect&bpo=36096

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30348


File: python.info,  Node: Tools/Demos<29>,  Next: C API<54>,  Prev: IDLE<39>,  Up: Python 3 8 0 alpha 3

1.23.61.9 Tools/Demos
.....................

   - bpo-35132(1): Fix py-list and py-bt commands of python-gdb.py on
     gdb7.

   - bpo-32217(2): Fix freeze script on Windows.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35132

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32217


File: python.info,  Node: C API<54>,  Prev: Tools/Demos<29>,  Up: Python 3 8 0 alpha 3

1.23.61.10 C API
................

   - bpo-36381(1): Raise ‘DeprecationWarning’ when ‘#’ formats are used
     for building or parsing values without ‘PY_SSIZE_T_CLEAN’.

   - bpo-36142(2): The whole coreconfig.h header is now excluded from
     Py_LIMITED_API. Move functions definitions into a new internal
     pycore_coreconfig.h header.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36381

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36142


File: python.info,  Node: Python 3 8 0 alpha 2,  Next: Python 3 8 0 alpha 1,  Prev: Python 3 8 0 alpha 3,  Up: Changelog

1.23.62 Python 3.8.0 alpha 2
----------------------------

'Release date: 2019-02-25'

* Menu:

* Core and Builtins: Core and Builtins<135>.
* Library: Library<137>.
* Documentation: Documentation<53>.
* Tests: Tests<55>.
* Windows: Windows<52>.
* IDLE: IDLE<40>.


File: python.info,  Node: Core and Builtins<135>,  Next: Library<137>,  Up: Python 3 8 0 alpha 2

1.23.62.1 Core and Builtins
...........................

   - bpo-36052(1): Raise a *note SyntaxError: 18d. when assigning a
     value to ‘__debug__’ with the Assignment Operator.  Contributed by
     Stéphane Wirtel and Pablo Galindo.

   - bpo-36012(2): Doubled the speed of class variable writes.  When a
     non-dunder attribute was updated, there was an unnecessary call to
     update slots.

   - bpo-35942(3): The error message emitted when returning invalid
     types from ‘__fspath__’ in interfaces that allow passing *note
     PathLike: c72. objects has been improved and now it does explain
     the origin of the error.

   - bpo-36016(4): ‘gc.get_objects’ can now receive an optional
     parameter indicating a generation to get objects from.  Patch by
     Pablo Galindo.

   - bpo-1054041(5): When the main interpreter exits due to an uncaught
     KeyboardInterrupt, the process now exits in the appropriate manner
     for its parent process to detect that a SIGINT or ^C terminated the
     process.  This allows shells and batch scripts to understand that
     the user has asked them to stop.

   - bpo-35992(6): Fix ‘__class_getitem__()’ not being called on a class
     with a custom non-subscriptable metaclass.

   - bpo-35993(7): Fix a crash on fork when using subinterpreters.
     Contributed by Stéphane Wirtel

   - bpo-35991(8): Fix a potential double free in
     Modules/_randommodule.c.

   - bpo-35961(9): Fix a crash in slice_richcompare(): use strong
     references rather than stolen references for the two temporary
     internal tuples.

   - bpo-35911(10): Enable the creation of cell objects by adding a
     ‘cell.__new__’ method, and expose the type ‘cell’ in ‘Lib/types.py’
     under the name CellType.  Patch by Pierre Glaser.

   - bpo-12822(11): Use monotonic clock for ‘pthread_cond_timedwait’
     when ‘pthread_condattr_setclock’ and ‘CLOCK_MONOTONIC’ are
     available.

   - bpo-15248(12): The compiler emits now syntax warnings in the case
     when a comma is likely missed before tuple or list.

   - bpo-35886(13): The implementation of PyInterpreterState has been
     moved into the internal header files (guarded by Py_BUILD_CORE).

   - bpo-31506(14): Clarify the errors reported when ‘object.__new__’
     and ‘object.__init__’ receive more than one argument.  Contributed
     by Sanyam Khurana.

   - bpo-35724(15): Signal-handling is now guaranteed to happen relative
     to the main interpreter.

   - bpo-33608(16): We added a new internal _Py_AddPendingCall() that
     operates relative to the provided interpreter.  This allows us to
     use the existing implementation to ask another interpreter to do
     work that cannot be done in the current interpreter, like decref an
     object the other interpreter owns.  The existing
     Py_AddPendingCall() only operates relative to the main interpreter.

   - bpo-33989(17): Fix a possible crash in *note list.sort(): bee. when
     sorting objects with ‘ob_type->tp_richcompare == NULL’.  Patch by
     Zackery Spytz.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36052

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36012

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35942

   (4) https://bugs.python.org/issue?@action=redirect&bpo=36016

   (5) https://bugs.python.org/issue?@action=redirect&bpo=1054041

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35992

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35993

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35991

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35961

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35911

   (11) https://bugs.python.org/issue?@action=redirect&bpo=12822

   (12) https://bugs.python.org/issue?@action=redirect&bpo=15248

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35886

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31506

   (15) https://bugs.python.org/issue?@action=redirect&bpo=35724

   (16) https://bugs.python.org/issue?@action=redirect&bpo=33608

   (17) https://bugs.python.org/issue?@action=redirect&bpo=33989


File: python.info,  Node: Library<137>,  Next: Documentation<53>,  Prev: Core and Builtins<135>,  Up: Python 3 8 0 alpha 2

1.23.62.2 Library
.................

   - bpo-35512(1): *note unittest.mock.patch.dict(): 1b83. used as a
     decorator with string target resolves the target during function
     call instead of during decorator construction.  Patch by
     Karthikeyan Singaravelan.

   - bpo-36018(2): Add statistics.NormalDist, a tool for creating and
     manipulating normal distributions of random variable.  Features a
     composite class that treats the mean and standard deviation of
     measurement data as single entity.

   - bpo-35904(3): Added statistics.fmean() as a faster, floating-point
     variant of the existing mean() function.

   - bpo-35918(4): Removed broken ‘has_key’ method from
     multiprocessing.managers.SyncManager.dict.  Contributed by Rémi
     Lapeyre.

   - bpo-18283(5): Add support for bytes to *note shutil.which(): 4b7.

   - bpo-35960(6): Fix *note dataclasses.field(): 1bb1. throwing away
     empty mapping objects passed as metadata.

   - bpo-35500(7): Write expected and actual call parameters on separate
     lines in *note unittest.mock.Mock.assert_called_with(): 1bb2.
     assertion errors.  Contributed by Susan Su.

   - bpo-35931(8): The *note pdb: a5. ‘debug’ command now gracefully
     handles syntax errors.

   - bpo-24209(9): In http.server script, rely on getaddrinfo to bind to
     preferred address based on the bind parameter.  Now default bind or
     binding to a name may bind to IPv6 or dual-stack, depending on the
     environment.

   - bpo-35321(10): Set ‘__spec__.origin’ of ‘_frozen_importlib’ to
     frozen so that it matches the behavior of
     ‘_frozen_importlib_external’.  Patch by Nina Zakharenko.

   - bpo-35378(11): Fix a reference issue inside ‘multiprocessing.Pool’
     that caused the pool to remain alive if it was deleted without
     being closed or terminated explicitly.  A new strong reference is
     added to the pool iterators to link the lifetime of the pool to the
     lifetime of its iterators so the pool does not get destroyed if a
     pool iterator is still alive.

   - bpo-34294(12): re module, fix wrong capturing groups in rare cases.
     *note re.search(): 1272, *note re.findall(): 1065, *note re.sub():
     2a3. and other functions that scan through string looking for a
     match, should reset capturing groups between two match attempts.
     Patch by Ma Lin.

   - bpo-35615(13): *note weakref: 114.: Fix a RuntimeError when copying
     a WeakKeyDictionary or a WeakValueDictionary, due to some keys or
     values disappearing while iterating.

   - bpo-35606(14): Implement *note math.prod(): a0f. as analogous
     function to *note sum(): 46d. that returns the product of a ‘start’
     value (default: 1) times an iterable of numbers.  Patch by Pablo
     Galindo.

   - bpo-32417(15): Performing arithmetic between *note
     datetime.datetime: 1cc. subclasses and *note datetime.timedelta:
     9da. now returns an object of the same type as the
     ‘datetime.datetime’ subclass.  As a result, *note
     datetime.datetime.astimezone(): 9db. and alternate constructors
     like *note datetime.datetime.now(): 4ef. and
     ‘datetime.fromtimestamp()’ called with a ‘tz’ argument now 'also'
     retain their subclass.

   - bpo-35153(16): Add 'headers' optional keyword-only parameter to
     *note xmlrpc.client.ServerProxy: a65, ‘xmlrpc.client.Transport’ and
     ‘xmlrpc.client.SafeTransport’.  Patch by Cédric Krier.

   - bpo-34572(17): Fix C implementation of pickle.loads to use
     importlib’s locking mechanisms, and thereby avoid using partially
     loaded modules.  Patch by Tim Burgess.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35512

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36018

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35904

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35918

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18283

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35960

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35500

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35931

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24209

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35321

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35378

   (12) https://bugs.python.org/issue?@action=redirect&bpo=34294

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35615

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35606

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32417

   (16) https://bugs.python.org/issue?@action=redirect&bpo=35153

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34572


File: python.info,  Node: Documentation<53>,  Next: Tests<55>,  Prev: Library<137>,  Up: Python 3 8 0 alpha 2

1.23.62.3 Documentation
.......................

   - bpo-36083(1): Fix formatting of –check-hash-based-pycs options in
     the manpage Synopsis.

   - bpo-36007(2): Bump minimum sphinx version to 1.8.  Patch by Anthony
     Sottile.

   - bpo-22062(3): Update documentation and docstrings for pathlib.
     Original patch by Mike Short.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=36083

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36007

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22062


File: python.info,  Node: Tests<55>,  Next: Windows<52>,  Prev: Documentation<53>,  Up: Python 3 8 0 alpha 2

1.23.62.4 Tests
...............

   - bpo-27313(1): Avoid test_ttk_guionly ComboboxTest failure with
     macOS Cocoa Tk.

   - bpo-36019(2): Add test.support.TEST_HTTP_URL and replace references
     of ‘http://www.example.com’ by this new constant.  Contributed by
     Stéphane Wirtel.

   - bpo-36037(3): Fix test_ssl for strict OpenSSL configuration like
     RHEL8 strict crypto policy.  Use older TLS version for minimum TLS
     version of the server SSL context if needed, to test TLS version
     older than default minimum TLS version.

   - bpo-35798(4): Added ‘test.support.check_syntax_warning()’.

   - bpo-35505(5): Make test_imap4_host_default_value independent on
     whether the local IMAP server is running.

   - bpo-35917(6): multiprocessing: provide unit tests for SyncManager
     and SharedMemoryManager classes + all the shareable types which are
     supposed to be supported by them.  (patch by Giampaolo Rodola)

   - bpo-35704(7): Skip ‘test_shutil.test_unpack_archive_xztar’ to
     prevent a MemoryError on 32-bit AIX when MAXDATA setting is less
     than 0x20000000.

     Patch by Michael Felt (aixtools)

   - bpo-34720(8): Assert m_state != NULL to mimic GC traversal
     functions that do not correctly handle module creation when the
     module state has not been created.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27313

   (2) https://bugs.python.org/issue?@action=redirect&bpo=36019

   (3) https://bugs.python.org/issue?@action=redirect&bpo=36037

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35798

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35505

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35917

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35704

   (8) https://bugs.python.org/issue?@action=redirect&bpo=34720


File: python.info,  Node: Windows<52>,  Next: IDLE<40>,  Prev: Tests<55>,  Up: Python 3 8 0 alpha 2

1.23.62.5 Windows
.................

   - bpo-35976(1): Added ARM build support to Windows build files in
     PCBuild.

   - bpo-35692(2): ‘pathlib’ no longer raises when checking file and
     directory existence on drives that are not ready

   - bpo-35872(3): Uses the base Python executable when invoking venv in
     a virtual environment

   - bpo-35873(4): Prevents venv paths being inherited by child
     processes

   - bpo-35299(5): Fix sysconfig detection of the source directory and
     distutils handling of pyconfig.h during PGO profiling

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35976

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35692

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35872

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35873

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35299


File: python.info,  Node: IDLE<40>,  Prev: Windows<52>,  Up: Python 3 8 0 alpha 2

1.23.62.6 IDLE
..............

   - bpo-24310(1): IDLE – Document settings dialog font tab sample.

   - bpo-35833(2): Revise IDLE doc for control codes sent to Shell.  Add
     a code example block.

   - bpo-35689(3): Add docstrings and unittests for colorizer.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24310

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35833

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35689


File: python.info,  Node: Python 3 8 0 alpha 1,  Next: Python 3 7 0 final,  Prev: Python 3 8 0 alpha 2,  Up: Changelog

1.23.63 Python 3.8.0 alpha 1
----------------------------

'Release date: 2019-02-03'

* Menu:

* Security: Security<43>.
* Core and Builtins: Core and Builtins<136>.
* Library: Library<138>.
* Documentation: Documentation<54>.
* Tests: Tests<56>.
* Build: Build<60>.
* Windows: Windows<53>.
* macOS: macOS<42>.
* IDLE: IDLE<41>.
* Tools/Demos: Tools/Demos<30>.
* C API: C API<55>.


File: python.info,  Node: Security<43>,  Next: Core and Builtins<136>,  Up: Python 3 8 0 alpha 1

1.23.63.1 Security
..................

   - bpo-35746(1): CVE 2019-5010(2): Fix a NULL pointer deref in ssl
     module.  The cert parser did not handle CRL distribution points
     with empty DP or URI correctly.  A malicious or buggy certificate
     can result into segfault.  Vulnerability (TALOS-2018-0758) reported
     by Colin Read and Nicolas Edet of Cisco.

   - bpo-34812(3): The *note -I: 968. command line option (run Python in
     isolated mode) is now also copied by the *note multiprocessing: 94.
     and ‘distutils’ modules when spawning child processes.  Previously,
     only *note -E: 967. and *note -s: 13db. options (enabled by ‘-I’)
     were copied.

   - bpo-34791(4): The xml.sax and xml.dom.domreg no longer use
     environment variables to override parser implementations when
     sys.flags.ignore_environment is set by -E or -I arguments.

   - bpo-17239(5): The xml.sax and xml.dom.minidom parsers no longer
     processes external entities by default.  External DTD and ENTITY
     declarations no longer load files or create network connections.

   - bpo-34623(6): CVE 2018-14647(7): The C accelerated _elementtree
     module now initializes hash randomization salt from _Py_HashSecret
     instead of libexpat’s default CSPRNG.

   - bpo-34405(8): Updated to OpenSSL 1.1.0i for Windows builds.

   - bpo-33871(9): Fixed sending the part of the file in *note
     os.sendfile(): b28. on macOS. Using the 'trailers' argument could
     cause sending more bytes from the input file than was specified.

   - bpo-32533(10): Fixed thread-safety of error handling in _ssl.

   - bpo-33136(11): Harden ssl module against LibreSSL CVE
     2018-8970(12).  X509_VERIFY_PARAM_set1_host() is called with an
     explicit namelen.  A new test ensures that NULL bytes are not
     allowed.

   - bpo-33001(13): Minimal fix to prevent buffer overrun in os.symlink
     on Windows

   - bpo-32981(14): Regexes in difflib and poplib were vulnerable to
     catastrophic backtracking.  These regexes formed potential DOS
     vectors (REDOS). They have been refactored.  This resolves CVE
     2018-1060(15) and CVE 2018-1061(16).  Patch by Jamie Davis.

   - bpo-28414(17): The ssl module now allows users to perform their own
     IDN en/decoding when using SNI.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35746

   (2) https://www.cve.org/CVERecord?id=CVE-2019-5010

   (3) https://bugs.python.org/issue?@action=redirect&bpo=34812

   (4) https://bugs.python.org/issue?@action=redirect&bpo=34791

   (5) https://bugs.python.org/issue?@action=redirect&bpo=17239

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34623

   (7) https://www.cve.org/CVERecord?id=CVE-2018-14647

   (8) https://bugs.python.org/issue?@action=redirect&bpo=34405

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33871

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32533

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33136

   (12) https://www.cve.org/CVERecord?id=CVE-2018-8970

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33001

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32981

   (15) https://www.cve.org/CVERecord?id=CVE-2018-1060

   (16) https://www.cve.org/CVERecord?id=CVE-2018-1061

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28414


File: python.info,  Node: Core and Builtins<136>,  Next: Library<138>,  Prev: Security<43>,  Up: Python 3 8 0 alpha 1

1.23.63.2 Core and Builtins
...........................

   - bpo-35877(1): Make parenthesis optional for named expressions in
     while statement.  Patch by Karthikeyan Singaravelan.

   - bpo-35814(2): Allow same right hand side expressions in annotated
     assignments as in normal ones.  In particular, ‘x: Tuple[int, int]
     = 1, 2’ (without parentheses on the right) is now allowed.

   - bpo-35766(3): Add the option to parse PEP 484 type comments in the
     ast module.  (Off by default.)  This is merging the key
     functionality of the third party fork thereof,
     [typed_ast](‘https://github.com/python/typed_ast’).

   - bpo-35713(4): Reorganize Python initialization to get working
     exceptions and sys.stderr earlier.

   - bpo-33416(5): Add end line and end column position information to
     the Python AST nodes.  This is a C-level backwards incompatible
     change.

   - bpo-35720(6): Fixed a minor memory leak in
     pymain_parse_cmdline_impl function in Modules/main.c

   - bpo-35634(7): ‘func(**kwargs)’ will now raise an error when
     ‘kwargs’ is a mapping containing multiple entries with the same
     key.  An error was already raised when other keyword arguments are
     passed before ‘**kwargs’ since Python 3.6.

   - bpo-35623(8): Fix a crash when sorting very long lists.  Patch by
     Stephan Hohe.

   - bpo-35214(9): clang Memory Sanitizer build instrumentation was
     added to work around false positives from posix, socket, time,
     test_io, and test_faulthandler.

   - bpo-35560(10): Fix an assertion error in *note format(): 622. in
     debug build for floating-point formatting with “n” format, zero
     padding and small width.  Release build is not impacted.  Patch by
     Karthikeyan Singaravelan.

   - bpo-35552(11): Format characters ‘%s’ and ‘%V’ in *note
     PyUnicode_FromFormat(): 38d. and ‘%s’ in *note
     PyBytes_FromFormat(): 1bba. no longer read memory past the limit if
     'precision' is specified.

   - bpo-35504(12): Fix segfaults and *note SystemError: 578.s when
     deleting certain attributes.  Patch by Zackery Spytz.

   - bpo-35504(13): Fixed a SystemError when delete the
     characters_written attribute of an OSError.

   - bpo-35494(14): Improved syntax error messages for unbalanced
     parentheses in f-string.

   - bpo-35444(15): Fixed error handling in pickling methods when fail
     to look up builtin “getattr”.  Sped up pickling iterators.

   - bpo-35436(16): Fix various issues with memory allocation error
     handling.  Patch by Zackery Spytz.

   - bpo-35423(17): Separate the signal handling trigger in the eval
     loop from the “pending calls” machinery.  There is no semantic
     change and the difference in performance is insignificant.

   - bpo-35357(18): Internal attributes’ names of unittest.mock._Call
     and unittest.mock.MagicProxy (name, parent & from_kall) are now
     prefixed with _mock_ in order to prevent clashes with widely used
     object attributes.  Fixed minor typo in test function name.

   - bpo-35372(19): Fixed the code page decoder for input longer than 2
     GiB containing undecodable bytes.

   - bpo-35336(20): Fix PYTHONCOERCECLOCALE=1 environment variable: only
     coerce the C locale if the LC_CTYPE locale is “C”.

   - bpo-31241(21): The 'lineno' and 'col_offset' attributes of AST
     nodes for list comprehensions, generator expressions and tuples are
     now point to the opening parenthesis or square brace.  For tuples
     without parenthesis they point to the position of the first item.

   - bpo-33954(22): For *note str.format(): 624, ‘float.__format__()’
     and ‘complex.__format__()’ methods for non-ASCII decimal point when
     using the “n” formatter.

   - bpo-35269(23): Fix a possible segfault involving a newly created
     coroutine.  Patch by Zackery Spytz.

   - bpo-35224(24): Implement PEP 572(25) (assignment expressions).
     Patch by Emily Morehouse.

   - bpo-32492(26): Speed up ‘namedtuple()’ attribute access by 1.6x
     using a C fast-path for the name descriptors.  Patch by Pablo
     Galindo.

   - bpo-35214(27): Fixed an out of bounds memory access when parsing a
     truncated unicode escape sequence at the end of a string such as
     ‘'\N'’.  It would read one byte beyond the end of the memory
     allocation.

   - bpo-35214(28): The interpreter and extension modules have had
     annotations added so that they work properly under clang’s Memory
     Sanitizer.  A new configure flag –with-memory-sanitizer has been
     added to make test builds of this nature easier to perform.

   - bpo-35193(29): Fix an off by one error in the bytecode peephole
     optimizer where it could read bytes beyond the end of bounds of an
     array when removing unreachable code.  This bug was present in
     every release of Python 3.6 and 3.7 until now.

   - bpo-35169(30): Improved error messages for forbidden assignments.

   - bpo-34022(31): Fix handling of hash-based bytecode files in *note
     zipimport: 132.  Patch by Elvis Pranskevichus.

   - bpo-28401(32): Debug builds will no longer to attempt to import
     extension modules built for the ABI as they were never compatible
     to begin with.  Patch by Stefano Rivera.

   - bpo-29341(33): Clarify in the docstrings of *note os: a1. methods
     that path-like objects are also accepted as input parameters.

   - bpo-35050(34): *note socket: cc.: Fix off-by-one bug in length
     check for ‘AF_ALG’ name and type.

   - bpo-29743(35): Raise *note ValueError: 202. instead of *note
     OverflowError: 888. in case of a negative ‘_length_’ in a *note
     ctypes.Array: 1bbb. subclass.  Also raise *note TypeError: 2c3.
     instead of *note AttributeError: 34e. for non-integer ‘_length_’.
     Original patch by Oren Milman.

   - bpo-16806(36): Fix ‘lineno’ and ‘col_offset’ for multi-line string
     tokens.

   - bpo-35029(37): *note SyntaxWarning: 469. raised as an exception at
     code generation time will be now replaced with a *note SyntaxError:
     18d. for better error reporting.

   - bpo-34983(38): Expose *note symtable.Symbol.is_nonlocal(): 1bbc. in
     the symtable module.  Patch by Pablo Galindo.

   - bpo-34974(39): *note bytes: 1c2. and *note bytearray: 2ea.
     constructors no longer convert unexpected exceptions (e.g.  *note
     MemoryError: 15ab. and *note KeyboardInterrupt: 9dc.) to *note
     TypeError: 2c3.

   - bpo-34939(40): Allow annotated names in module namespace that are
     declared global before the annotation happens.  Patch by Pablo
     Galindo.

   - bpo-34973(41): Fixed crash in *note bytes(): 1c2. when the *note
     list: 614. argument is mutated while it is iterated.

   - bpo-34876(42): The 'lineno' and 'col_offset' attributes of the AST
     for decorated function and class refer now to the position of the
     corresponding ‘def’, ‘async def’ and ‘class’ instead of the
     position of the first decorator.  This leads to more correct line
     reporting in tracing.  This is the only case when the position of
     child AST nodes can precede the position of the parent AST node.

   - bpo-34879(43): Fix a possible null pointer dereference in
     bytesobject.c.  Patch by Zackery Spytz.

   - bpo-34784(44): Fix the implementation of PyStructSequence_NewType
     in order to create heap allocated StructSequences.

   - bpo-32912(45): A *note SyntaxWarning: 469. is now emitted instead
     of a *note DeprecationWarning: 1a5. for invalid escape sequences in
     string and bytes literals.

   - bpo-34854(46): Fixed a crash in compiling string annotations
     containing a lambda with a keyword-only argument that doesn’t have
     a default value.

   - bpo-34850(47): The compiler now produces a *note SyntaxWarning:
     469. when identity checks (‘is’ and ‘is not’) are used with certain
     types of literals (e.g.  strings, ints).  These can often work by
     accident in CPython, but are not guaranteed by the language spec.
     The warning advises users to use equality tests (‘==’ and ‘!=’)
     instead.

   - bpo-34824(48): Fix a possible null pointer dereference in
     Modules/_ssl.c.  Patch by Zackery Spytz.

   - bpo-30156(49): The C function ‘property_descr_get()’ uses a
     “cached” tuple to optimize function calls.  But this tuple can be
     discovered in debug mode with *note sys.getobjects(): 42a.  Remove
     the optimization, it’s not really worth it and it causes 3
     different crashes last years.

   - bpo-34762(50): Fix contextvars C API to use PyObject* pointer
     types.

   - bpo-34751(51): The hash function for tuples is now based on xxHash
     which gives better collision results on (formerly) pathological
     cases.  Additionally, on 64-bit systems it improves tuple hashes in
     general.  Patch by Jeroen Demeyer with substantial contributions by
     Tim Peters.

   - bpo-34735(52): Fix a memory leak in Modules/timemodule.c.  Patch by
     Zackery Spytz.

   - bpo-34683(53): Fixed a bug where some SyntaxError error pointed to
     locations that were off-by-one.

   - bpo-34651(54): Only allow the main interpreter to fork.  The avoids
     the possibility of affecting the main interpreter, which is
     critical to operation of the runtime.

   - bpo-34653(55): Remove unused function
     PyParser_SimpleParseStringFilename.

   - bpo-32236(56): Warn that line buffering is not supported if *note
     open(): 51f. is called with binary mode and ‘buffering=1’.

   - bpo-34641(57): Further restrict the syntax of the left-hand side of
     keyword arguments in function calls.  In particular,
     ‘f((keyword)=arg)’ is now disallowed.

   - bpo-34637(58): Make the 'start' argument to 'sum()' visible as a
     keyword argument.

   - bpo-1621(59): Do not assume signed integer overflow behavior (C
     undefined behavior) when performing set hash table resizing.

   - bpo-34588(60): Fix an off-by-one in the recursive call pruning
     feature of traceback formatting.

   - bpo-34485(61): On Windows, the LC_CTYPE is now set to the user
     preferred locale at startup.  Previously, the LC_CTYPE locale was
     “C” at startup, but changed when calling setlocale(LC_CTYPE, “”) or
     setlocale(LC_ALL, “”).

   - bpo-34485(62): Standard streams like sys.stdout now use the
     “surrogateescape” error handler, instead of “strict”, on the POSIX
     locale (when the C locale is not coerced and the UTF-8 Mode is
     disabled).

   - bpo-34485(63): Fix the error handler of standard streams like
     sys.stdout: PYTHONIOENCODING=”:” is now ignored instead of setting
     the error handler to “strict”.

   - bpo-34485(64): Python now gets the locale encoding with C code to
     initialize the encoding of standard streams like sys.stdout.
     Moreover, the encoding is now initialized to the Python codec name
     to get a normalized encoding name and to ensure that the codec is
     loaded.  The change avoids importing _bootlocale and _locale
     modules at startup by default.

   - bpo-34527(65): On FreeBSD, Py_DecodeLocale() and Py_EncodeLocale()
     now also forces the ASCII encoding if the LC_CTYPE locale is
     “POSIX”, not only if the LC_CTYPE locale is “C”.

   - bpo-34527(66): The UTF-8 Mode is now also enabled by the “POSIX”
     locale, not only by the “C” locale.

   - bpo-34403(67): On HP-UX with C or POSIX locale,
     sys.getfilesystemencoding() now returns “ascii” instead of “roman8”
     (when the UTF-8 Mode is disabled and the C locale is not coerced).

   - bpo-34523(68): The Python filesystem encoding is now read earlier
     during the Python initialization.

   - bpo-12458(69): Tracebacks show now correct line number for
     subexpressions in multiline expressions.  Tracebacks show now the
     line number of the first line for multiline expressions instead of
     the line number of the last subexpression.

   - bpo-34408(70): Prevent a null pointer dereference and resource
     leakage in ‘PyInterpreterState_New()’.

   - bpo-34400(71): Fix undefined behavior in parsetok.c.  Patch by
     Zackery Spytz.

   - bpo-33073(72): Added as_integer_ratio to ints to make them more
     interoperable with floats.

   - bpo-34377(73): Update valgrind suppression list to use
     ‘_PyObject_Free’/‘_PyObject_Realloc’ instead of
     ‘PyObject_Free’/‘PyObject_Realloc’.

   - bpo-34353(74): Added the “socket” option in the ‘stat.filemode()’
     Python implementation to match the C implementation.

   - bpo-34320(75): Fix ‘dict(od)’ didn’t copy iteration order of
     OrderedDict.

   - bpo-34113(76): Fixed crash on debug builds when opcode stack was
     adjusted with negative numbers.  Patch by Constantin Petrisor.

   - bpo-34100(77): Compiler now merges constants in tuples and
     frozensets recursively.  Code attributes like ‘co_names’ are merged
     too.

   - bpo-34151(78): Performance of list concatenation, repetition and
     slicing operations is slightly improved.  Patch by Sergey Fedoseev.

   - bpo-34170(79): -X dev: it is now possible to override the memory
     allocator using PYTHONMALLOC even if the developer mode is enabled.

   - bpo-33237(80): Improved *note AttributeError: 34e. message for
     partially initialized module.

   - bpo-34149(81): Fix min and max functions to get default behavior
     when key is None.

   - bpo-34125(82): Profiling of unbound built-in methods now works when
     ‘**kwargs’ is given.

   - bpo-34141(83): Optimized pickling atomic types (None, bool, int,
     float, bytes, str).

   - bpo-34126(84): Fix crashes when profiling certain invalid calls of
     unbound methods.  Patch by Jeroen Demeyer.

   - bpo-24618(85): Fixed reading invalid memory when create the code
     object with too small varnames tuple or too large argument counts.

   - bpo-34068(86): In *note io.IOBase.close(): 1f6, ensure that the
     *note closed: 1bbd. attribute is not set with a live exception.
     Patch by Zackery Spytz and Serhiy Storchaka.

   - bpo-34087(87): Fix buffer overflow while converting unicode to
     numeric values.

   - bpo-34080(88): Fixed a memory leak in the compiler when it raised
     some uncommon errors during tokenizing.

   - bpo-34066(89): Disabled interruption by Ctrl-C between calling
     ‘open()’ and entering a 'with' block in ‘with open()’.

   - bpo-34042(90): Fix dict.copy() to maintain correct total refcount
     (as reported by sys.gettotalrefcount()).

   - bpo-33418(91): Fix potential memory leak in function object when it
     creates reference cycle.

   - bpo-33985(92): Implement contextvars.ContextVar.name attribute.

   - bpo-33956(93): Update vendored Expat library copy to version 2.2.5.

   - bpo-24596(94): Decref the module object in *note
     PyRun_SimpleFileExFlags(): 1a70. before calling *note
     PyErr_Print(): 1ad3.  Patch by Zackery Spytz.

   - bpo-33451(95): Close directly executed pyc files before calling
     ‘PyEval_EvalCode()’.

   - bpo-1617161(96): The hash of ‘BuiltinMethodType’ instances (methods
     of built-in classes) now depends on the hash of the identity of
     '__self__' instead of its value.  The hash and equality of
     ‘ModuleType’ and ‘MethodWrapperType’ instances (methods of
     user-defined classes and some methods of built-in classes like
     ‘str.__add__’) now depend on the hash and equality of the identity
     of '__self__' instead of its value.  ‘MethodWrapperType’ instances
     no longer support ordering.

   - bpo-33824(97): Fix “LC_ALL=C python3.7 -V”: reset properly the
     command line parser when the encoding changes after reading the
     Python configuration.

   - bpo-33803(98): Fix a crash in hamt.c caused by enabling GC tracking
     for an object that hadn’t all of its fields set to NULL.

   - bpo-33738(99): Seven macro incompatibilities with the Limited API
     were fixed, and the macros *note PyIter_Check(): 1a58, *note
     PyIndex_Check(): 994. and *note PyExceptionClass_Name(): a74. were
     added as functions.  A script for automatic macro checks was added.

   - bpo-33786(100): Fix asynchronous generators to handle GeneratorExit
     in athrow() correctly

   - bpo-30167(101): ‘PyRun_SimpleFileExFlags’ removes ‘__cached__’ from
     module in addition to ‘__file__’.

   - bpo-33706(102): Fix a crash in Python initialization when parsing
     the command line options.  Thanks Christoph Gohlke for the bug
     report and the fix!

   - bpo-33597(103): Reduce ‘PyGC_Head’ size from 3 words to 2 words.

   - bpo-30654(104): Fixed reset of the SIGINT handler to SIG_DFL on
     interpreter shutdown even when there was a custom handler set
     previously.  Patch by Philipp Kerling.

   - bpo-33622(105): Fixed a leak when the garbage collector fails to
     add an object with the ‘__del__’ method or referenced by it into
     the *note gc.garbage: 1206. list.  *note PyGC_Collect(): 998. can
     now be called when an exception is set and preserves it.

   - bpo-33462(106): Make dict and dict views reversible.  Patch by Rémi
     Lapeyre.

   - bpo-23722(107): A *note RuntimeError: 195. is now raised when the
     custom metaclass doesn’t provide the ‘__classcell__’ entry in the
     namespace passed to ‘type.__new__’.  A *note DeprecationWarning:
     1a5. was emitted in Python 3.6–3.7.

   - bpo-33499(108): Add *note PYTHONPYCACHEPREFIX: 9ae. environment
     variable and *note -X: 176. ‘pycache_prefix’ command-line option to
     set an alternate root directory for writing module bytecode cache
     files.

   - bpo-25711(109): The *note zipimport: 132. module has been rewritten
     in pure Python.

   - bpo-33509(110): Fix module_globals parameter of
     warnings.warn_explicit(): don’t crash if module_globals is not a
     dict.

   - bpo-31849(111): Fix signed/unsigned comparison warning in pyhash.c.

   - bpo-33475(112): Fixed miscellaneous bugs in converting annotations
     to strings and optimized parentheses in the string representation.

   - bpo-20104(113): Added support for the ‘setpgroup’, ‘resetids’,
     ‘setsigmask’, ‘setsigdef’ and ‘scheduler’ parameters of
     ‘posix_spawn’.  Patch by Pablo Galindo.

   - bpo-33391(114): Fix a leak in set_symmetric_difference().

   - bpo-33363(115): Raise a SyntaxError for ‘async with’ and ‘async
     for’ statements outside of async functions.

   - bpo-28055(116): Fix unaligned accesses in siphash24().  Patch by
     Rolf Eike Beer.

   - bpo-33128(117): Fix a bug that causes PathFinder to appear twice on
     sys.meta_path.  Patch by Pablo Galindo Salgado.

   - bpo-33331(118): Modules imported last are now cleared first at
     interpreter shutdown.

   - bpo-33312(119): Fixed clang ubsan (undefined behavior sanitizer)
     warnings in dictobject.c by adjusting how the internal struct
     _dictkeysobject shared keys structure is declared.

   - bpo-33305(120): Improved syntax error messages for invalid
     numerical literals.

   - bpo-33306(121): Improved syntax error messages for unbalanced
     parentheses.

   - bpo-33234(122): The list constructor will pre-size and not
     over-allocate when the input length is known.

   - bpo-33270(123): Intern the names for all anonymous code objects.
     Patch by Zackery Spytz.

   - bpo-30455(124): The C and Python code and the documentation related
     to tokens are now generated from a single source file
     ‘Grammar/Tokens’.

   - bpo-33176(125): Add a ‘toreadonly()’ method to memoryviews.

   - bpo-33231(126): Fix potential memory leak in ‘normalizestring()’.

   - bpo-33205(127): Change dict growth function from
     ‘round_up_to_power_2(used*2+hashtable_size/2)’ to
     ‘round_up_to_power_2(used*3)’.  Previously, dict is shrinked only
     when ‘used == 0’.  Now dict has more chance to be shrinked.

   - bpo-29922(128): Improved error messages in ‘async with’ when
     ‘__aenter__()’ or ‘__aexit__()’ return non-awaitable object.

   - bpo-33199(129): Fix ‘ma_version_tag’ in dict implementation is
     uninitialized when copying from key-sharing dict.

   - bpo-33053(130): When using the -m switch, sys.path[0] is now
     explicitly expanded as the 'starting' working directory, rather
     than being left as the empty path (which allows imports from the
     current working directory at the time of the import)

   - bpo-33138(131): Changed standard error message for non-pickleable
     and non-copyable types.  It now says “cannot pickle” instead of
     “can’t pickle” or “cannot serialize”.

   - bpo-33018(132): Improve consistency of errors raised by
     ‘issubclass()’ when called with a non-class and an abstract base
     class as the first and second arguments, respectively.  Patch by
     Josh Bronson.

   - bpo-33083(133): ‘math.factorial’ no longer accepts arguments that
     are not int-like.  Patch by Pablo Galindo.

   - bpo-33041(134): Added new opcode *note END_ASYNC_FOR: abf. and
     fixes the following issues:

        * Setting global *note StopAsyncIteration: 1bbe. no longer
          breaks ‘async for’ loops.

        * Jumping into an ‘async for’ loop is now disabled.

        * Jumping out of an ‘async for’ loop no longer corrupts the
          stack.

   - bpo-25750(135): Fix rare Python crash due to bad refcounting in
     ‘type_getattro()’ if a descriptor deletes itself from the class.
     Patch by Jeroen Demeyer.

   - bpo-33041(136): Fixed bytecode generation for “async for” with a
     complex target.  A StopAsyncIteration raised on assigning or
     unpacking will be now propagated instead of stopping the iteration.

   - bpo-33026(137): Fixed jumping out of “with” block by setting
     f_lineno.

   - bpo-33005(138): Fix a crash on fork when using a custom memory
     allocator (ex: using PYTHONMALLOC env var).  _PyGILState_Reinit()
     and _PyInterpreterState_Enable() now use the default RAW memory
     allocator to allocate a new interpreters mutex on fork.

   - bpo-32911(139): Due to unexpected compatibility issues discovered
     during downstream beta testing, reverted bpo-29463(140).
     ‘docstring’ field is removed from Module, ClassDef, FunctionDef,
     and AsyncFunctionDef ast nodes which was added in 3.7a1.  Docstring
     expression is restored as a first statement in their body.  Based
     on patch by Inada Naoki.

   - bpo-17288(141): Prevent jumps from ‘return’ and ‘exception’ trace
     events.

   - bpo-32946(142): Importing names from already imported module with
     “from … import …” is now 30% faster if the module is not a package.

   - bpo-32932(143): Make error message more revealing when there are
     non-str objects in ‘__all__’.

   - bpo-32925(144): Optimized iterating and containing test for literal
     lists consisting of non-constants: ‘x in [a, b]’ and ‘for x in [a,
     b]’.  The case of all constant elements already was optimized.

   - bpo-32889(145): Update Valgrind suppression list to account for the
     rename of ‘Py_ADDRESS_IN_RANG’ to ‘address_in_range’.

   - bpo-32836(146): Don’t use temporary variables in cases of
     list/dict/set comprehensions

   - bpo-31356(147): Remove the new API added in bpo-31356(148)
     (gc.ensure_disabled() context manager).

   - bpo-32305(149): For namespace packages, ensure that both ‘__file__’
     and ‘__spec__.origin’ are set to None.

   - bpo-32303(150): Make sure ‘__spec__.loader’ matches ‘__loader__’
     for namespace packages.

   - bpo-32711(151): Fix the warning messages for Python/ast_unparse.c.
     Patch by Stéphane Wirtel

   - bpo-32583(152): Fix possible crashing in builtin Unicode decoders
     caused by write out-of-bound errors when using customized decode
     error handlers.

   - bpo-32489(153): A *note continue: 9d4. statement is now allowed in
     the *note finally: 9d5. clause.

   - bpo-17611(154): Simplified the interpreter loop by moving the logic
     of unrolling the stack of blocks into the compiler.  The compiler
     emits now explicit instructions for adjusting the stack of values
     and calling the cleaning up code for *note break: abe, *note
     continue: 9d4. and *note return: 9d9.

     Removed opcodes ‘BREAK_LOOP’, ‘CONTINUE_LOOP’, ‘SETUP_LOOP’ and
     ‘SETUP_EXCEPT’.  Added new opcodes ‘ROT_FOUR’, ‘BEGIN_FINALLY’ and
     ‘CALL_FINALLY’ and ‘POP_FINALLY’.  Changed the behavior of
     ‘END_FINALLY’ and ‘WITH_CLEANUP_START’.

   - bpo-32285(155): New function unicodedata.is_normalized, which can
     check whether a string is in a specific normal form.

   - bpo-10544(156): Yield expressions are now disallowed in
     comprehensions and generator expressions except the expression for
     the outermost iterable.

   - bpo-32117(157): Iterable unpacking is now allowed without
     parentheses in yield and return statements, e.g.  ‘yield 1, 2, 3,
     *rest’.  Thanks to David Cuthbert for the change and Jordan Chapman
     for added tests.

   - bpo-31902(158): Fix the ‘col_offset’ attribute for ast nodes
     ‘ast.AsyncFor’, ‘ast.AsyncFunctionDef’, and ‘ast.AsyncWith’.
     Previously, ‘col_offset’ pointed to the keyword after ‘async’.

   - bpo-25862(159): Fix assertion failures in the ‘tell()’ method of
     ‘io.TextIOWrapper’.  Patch by Zackery Spytz.

   - bpo-21983(160): Fix a crash in ‘ctypes.cast()’ in case the type
     argument is a ctypes structured data type.  Patch by Eryk Sun and
     Oren Milman.

   - bpo-31577(161): Fix a crash in ‘os.utime()’ in case of a bad ns
     argument.  Patch by Oren Milman.

   - bpo-29832(162): Remove references to ‘getsockaddrarg’ from various
     socket error messages.  Patch by Oren Milman.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35877

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35814

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35766

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35713

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33416

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35720

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35634

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35623

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35214

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35560

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35552

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35504

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35504

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35494

   (15) https://bugs.python.org/issue?@action=redirect&bpo=35444

   (16) https://bugs.python.org/issue?@action=redirect&bpo=35436

   (17) https://bugs.python.org/issue?@action=redirect&bpo=35423

   (18) https://bugs.python.org/issue?@action=redirect&bpo=35357

   (19) https://bugs.python.org/issue?@action=redirect&bpo=35372

   (20) https://bugs.python.org/issue?@action=redirect&bpo=35336

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31241

   (22) https://bugs.python.org/issue?@action=redirect&bpo=33954

   (23) https://bugs.python.org/issue?@action=redirect&bpo=35269

   (24) https://bugs.python.org/issue?@action=redirect&bpo=35224

   (25) https://peps.python.org/pep-0572/

   (26) https://bugs.python.org/issue?@action=redirect&bpo=32492

   (27) https://bugs.python.org/issue?@action=redirect&bpo=35214

   (28) https://bugs.python.org/issue?@action=redirect&bpo=35214

   (29) https://bugs.python.org/issue?@action=redirect&bpo=35193

   (30) https://bugs.python.org/issue?@action=redirect&bpo=35169

   (31) https://bugs.python.org/issue?@action=redirect&bpo=34022

   (32) https://bugs.python.org/issue?@action=redirect&bpo=28401

   (33) https://bugs.python.org/issue?@action=redirect&bpo=29341

   (34) https://bugs.python.org/issue?@action=redirect&bpo=35050

   (35) https://bugs.python.org/issue?@action=redirect&bpo=29743

   (36) https://bugs.python.org/issue?@action=redirect&bpo=16806

   (37) https://bugs.python.org/issue?@action=redirect&bpo=35029

   (38) https://bugs.python.org/issue?@action=redirect&bpo=34983

   (39) https://bugs.python.org/issue?@action=redirect&bpo=34974

   (40) https://bugs.python.org/issue?@action=redirect&bpo=34939

   (41) https://bugs.python.org/issue?@action=redirect&bpo=34973

   (42) https://bugs.python.org/issue?@action=redirect&bpo=34876

   (43) https://bugs.python.org/issue?@action=redirect&bpo=34879

   (44) https://bugs.python.org/issue?@action=redirect&bpo=34784

   (45) https://bugs.python.org/issue?@action=redirect&bpo=32912

   (46) https://bugs.python.org/issue?@action=redirect&bpo=34854

   (47) https://bugs.python.org/issue?@action=redirect&bpo=34850

   (48) https://bugs.python.org/issue?@action=redirect&bpo=34824

   (49) https://bugs.python.org/issue?@action=redirect&bpo=30156

   (50) https://bugs.python.org/issue?@action=redirect&bpo=34762

   (51) https://bugs.python.org/issue?@action=redirect&bpo=34751

   (52) https://bugs.python.org/issue?@action=redirect&bpo=34735

   (53) https://bugs.python.org/issue?@action=redirect&bpo=34683

   (54) https://bugs.python.org/issue?@action=redirect&bpo=34651

   (55) https://bugs.python.org/issue?@action=redirect&bpo=34653

   (56) https://bugs.python.org/issue?@action=redirect&bpo=32236

   (57) https://bugs.python.org/issue?@action=redirect&bpo=34641

   (58) https://bugs.python.org/issue?@action=redirect&bpo=34637

   (59) https://bugs.python.org/issue?@action=redirect&bpo=1621

   (60) https://bugs.python.org/issue?@action=redirect&bpo=34588

   (61) https://bugs.python.org/issue?@action=redirect&bpo=34485

   (62) https://bugs.python.org/issue?@action=redirect&bpo=34485

   (63) https://bugs.python.org/issue?@action=redirect&bpo=34485

   (64) https://bugs.python.org/issue?@action=redirect&bpo=34485

   (65) https://bugs.python.org/issue?@action=redirect&bpo=34527

   (66) https://bugs.python.org/issue?@action=redirect&bpo=34527

   (67) https://bugs.python.org/issue?@action=redirect&bpo=34403

   (68) https://bugs.python.org/issue?@action=redirect&bpo=34523

   (69) https://bugs.python.org/issue?@action=redirect&bpo=12458

   (70) https://bugs.python.org/issue?@action=redirect&bpo=34408

   (71) https://bugs.python.org/issue?@action=redirect&bpo=34400

   (72) https://bugs.python.org/issue?@action=redirect&bpo=33073

   (73) https://bugs.python.org/issue?@action=redirect&bpo=34377

   (74) https://bugs.python.org/issue?@action=redirect&bpo=34353

   (75) https://bugs.python.org/issue?@action=redirect&bpo=34320

   (76) https://bugs.python.org/issue?@action=redirect&bpo=34113

   (77) https://bugs.python.org/issue?@action=redirect&bpo=34100

   (78) https://bugs.python.org/issue?@action=redirect&bpo=34151

   (79) https://bugs.python.org/issue?@action=redirect&bpo=34170

   (80) https://bugs.python.org/issue?@action=redirect&bpo=33237

   (81) https://bugs.python.org/issue?@action=redirect&bpo=34149

   (82) https://bugs.python.org/issue?@action=redirect&bpo=34125

   (83) https://bugs.python.org/issue?@action=redirect&bpo=34141

   (84) https://bugs.python.org/issue?@action=redirect&bpo=34126

   (85) https://bugs.python.org/issue?@action=redirect&bpo=24618

   (86) https://bugs.python.org/issue?@action=redirect&bpo=34068

   (87) https://bugs.python.org/issue?@action=redirect&bpo=34087

   (88) https://bugs.python.org/issue?@action=redirect&bpo=34080

   (89) https://bugs.python.org/issue?@action=redirect&bpo=34066

   (90) https://bugs.python.org/issue?@action=redirect&bpo=34042

   (91) https://bugs.python.org/issue?@action=redirect&bpo=33418

   (92) https://bugs.python.org/issue?@action=redirect&bpo=33985

   (93) https://bugs.python.org/issue?@action=redirect&bpo=33956

   (94) https://bugs.python.org/issue?@action=redirect&bpo=24596

   (95) https://bugs.python.org/issue?@action=redirect&bpo=33451

   (96) https://bugs.python.org/issue?@action=redirect&bpo=1617161

   (97) https://bugs.python.org/issue?@action=redirect&bpo=33824

   (98) https://bugs.python.org/issue?@action=redirect&bpo=33803

   (99) https://bugs.python.org/issue?@action=redirect&bpo=33738

   (100) https://bugs.python.org/issue?@action=redirect&bpo=33786

   (101) https://bugs.python.org/issue?@action=redirect&bpo=30167

   (102) https://bugs.python.org/issue?@action=redirect&bpo=33706

   (103) https://bugs.python.org/issue?@action=redirect&bpo=33597

   (104) https://bugs.python.org/issue?@action=redirect&bpo=30654

   (105) https://bugs.python.org/issue?@action=redirect&bpo=33622

   (106) https://bugs.python.org/issue?@action=redirect&bpo=33462

   (107) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (108) https://bugs.python.org/issue?@action=redirect&bpo=33499

   (109) https://bugs.python.org/issue?@action=redirect&bpo=25711

   (110) https://bugs.python.org/issue?@action=redirect&bpo=33509

   (111) https://bugs.python.org/issue?@action=redirect&bpo=31849

   (112) https://bugs.python.org/issue?@action=redirect&bpo=33475

   (113) https://bugs.python.org/issue?@action=redirect&bpo=20104

   (114) https://bugs.python.org/issue?@action=redirect&bpo=33391

   (115) https://bugs.python.org/issue?@action=redirect&bpo=33363

   (116) https://bugs.python.org/issue?@action=redirect&bpo=28055

   (117) https://bugs.python.org/issue?@action=redirect&bpo=33128

   (118) https://bugs.python.org/issue?@action=redirect&bpo=33331

   (119) https://bugs.python.org/issue?@action=redirect&bpo=33312

   (120) https://bugs.python.org/issue?@action=redirect&bpo=33305

   (121) https://bugs.python.org/issue?@action=redirect&bpo=33306

   (122) https://bugs.python.org/issue?@action=redirect&bpo=33234

   (123) https://bugs.python.org/issue?@action=redirect&bpo=33270

   (124) https://bugs.python.org/issue?@action=redirect&bpo=30455

   (125) https://bugs.python.org/issue?@action=redirect&bpo=33176

   (126) https://bugs.python.org/issue?@action=redirect&bpo=33231

   (127) https://bugs.python.org/issue?@action=redirect&bpo=33205

   (128) https://bugs.python.org/issue?@action=redirect&bpo=29922

   (129) https://bugs.python.org/issue?@action=redirect&bpo=33199

   (130) https://bugs.python.org/issue?@action=redirect&bpo=33053

   (131) https://bugs.python.org/issue?@action=redirect&bpo=33138

   (132) https://bugs.python.org/issue?@action=redirect&bpo=33018

   (133) https://bugs.python.org/issue?@action=redirect&bpo=33083

   (134) https://bugs.python.org/issue?@action=redirect&bpo=33041

   (135) https://bugs.python.org/issue?@action=redirect&bpo=25750

   (136) https://bugs.python.org/issue?@action=redirect&bpo=33041

   (137) https://bugs.python.org/issue?@action=redirect&bpo=33026

   (138) https://bugs.python.org/issue?@action=redirect&bpo=33005

   (139) https://bugs.python.org/issue?@action=redirect&bpo=32911

   (140) https://bugs.python.org/issue?@action=redirect&bpo=29463

   (141) https://bugs.python.org/issue?@action=redirect&bpo=17288

   (142) https://bugs.python.org/issue?@action=redirect&bpo=32946

   (143) https://bugs.python.org/issue?@action=redirect&bpo=32932

   (144) https://bugs.python.org/issue?@action=redirect&bpo=32925

   (145) https://bugs.python.org/issue?@action=redirect&bpo=32889

   (146) https://bugs.python.org/issue?@action=redirect&bpo=32836

   (147) https://bugs.python.org/issue?@action=redirect&bpo=31356

   (148) https://bugs.python.org/issue?@action=redirect&bpo=31356

   (149) https://bugs.python.org/issue?@action=redirect&bpo=32305

   (150) https://bugs.python.org/issue?@action=redirect&bpo=32303

   (151) https://bugs.python.org/issue?@action=redirect&bpo=32711

   (152) https://bugs.python.org/issue?@action=redirect&bpo=32583

   (153) https://bugs.python.org/issue?@action=redirect&bpo=32489

   (154) https://bugs.python.org/issue?@action=redirect&bpo=17611

   (155) https://bugs.python.org/issue?@action=redirect&bpo=32285

   (156) https://bugs.python.org/issue?@action=redirect&bpo=10544

   (157) https://bugs.python.org/issue?@action=redirect&bpo=32117

   (158) https://bugs.python.org/issue?@action=redirect&bpo=31902

   (159) https://bugs.python.org/issue?@action=redirect&bpo=25862

   (160) https://bugs.python.org/issue?@action=redirect&bpo=21983

   (161) https://bugs.python.org/issue?@action=redirect&bpo=31577

   (162) https://bugs.python.org/issue?@action=redirect&bpo=29832


File: python.info,  Node: Library<138>,  Next: Documentation<54>,  Prev: Core and Builtins<136>,  Up: Python 3 8 0 alpha 1

1.23.63.3 Library
.................

   - bpo-35845(1): Add ‘order’ parameter to memoryview.tobytes().

   - bpo-35864(2): The _asdict() method for collections.namedtuple now
     returns a regular dict instead of an OrderedDict.

   - bpo-35537(3): An ExitStack is now used internally within
     subprocess.Popen to clean up pipe file handles.  No behavior change
     in normal operation.  But if closing one handle were ever to cause
     an exception, the others will now be closed instead of leaked.
     (patch by Giampaolo Rodola)

   - bpo-35847(4): RISC-V needed the CTYPES_PASS_BY_REF_HACK. Fixes
     ctypes Structure test_pass_by_value.

   - bpo-35813(5): Shared memory submodule added to multiprocessing to
     avoid need for serialization between processes

   - bpo-35780(6): Fix lru_cache() errors arising in recursive,
     reentrant, or multi-threaded code.  These errors could result in
     orphan links and in the cache being trapped in a state with fewer
     than the specified maximum number of links.  Fix handling of
     negative maxsize which should have been treated as zero.  Fix
     errors in toggling the “full” status flag.  Fix misordering of
     links when errors are encountered.  Sync-up the C code and pure
     Python code for the space saving path in functions with a single
     positional argument.  In this common case, the space overhead of an
     lru cache entry is reduced by almost half.  Fix counting of cache
     misses.  In error cases, the miss count was out of sync with the
     actual number of times the underlying user function was called.

   - bpo-35537(7): *note os.posix_spawn(): 220. and *note
     os.posix_spawnp(): 15b4. now have a 'setsid' parameter.

   - bpo-23846(8): *note asyncio.ProactorEventLoop: 60c. now catches and
     logs send errors when the self-pipe is full.

   - bpo-34323(9): *note asyncio: a.: Enhance ‘IocpProactor.close()’
     log: wait 1 second before the first log, then log every second.
     Log also the number of seconds since ‘close()’ was called.

   - bpo-35674(10): Add a new *note os.posix_spawnp(): 15b4. function.
     Patch by Joannah Nanjekye.

   - bpo-35733(11): ‘ast.Constant(boolean)’ no longer an instance of
     ‘ast.Num’.  Patch by Anthony Sottile.

   - bpo-35726(12): QueueHandler.prepare() now makes a copy of the
     record before modifying and enqueueing it, to avoid affecting other
     handlers in the chain.

   - bpo-35719(13): Sped up multi-argument *note math: 8e. functions
     atan2(), copysign(), remainder() and hypot() by 1.3–2.5 times.

   - bpo-35717(14): Fix KeyError exception raised when using enums and
     compile.  Patch contributed by Rémi Lapeyre.

   - bpo-35699(15): Fixed detection of Visual Studio Build Tools 2017 in
     distutils

   - bpo-32710(16): Fix memory leaks in asyncio ProactorEventLoop on
     overlapped operation failure.

   - bpo-35702(17): The *note time.CLOCK_UPTIME_RAW: a50. constant is
     now available for macOS 10.12.

   - bpo-32710(18): Fix a memory leak in asyncio in the
     ProactorEventLoop when ‘ReadFile()’ or ‘WSASend()’ overlapped
     operation fail immediately: release the internal buffer.

   - bpo-35682(19): Fix ‘asyncio.ProactorEventLoop.sendfile()’: don’t
     attempt to set the result of an internal future if it’s already
     done.

   - bpo-35283(20): Add a deprecated warning for the
     ‘threading.Thread.isAlive()’ method.  Patch by Donghee Na.

   - bpo-35664(21): Improve operator.itemgetter() performance by 33%
     with optimized argument handling and with adding a fast path for
     the common case of a single non-negative integer index into a tuple
     (which is the typical use case in the standard library).

   - bpo-35643(22): Fixed a SyntaxWarning: invalid escape sequence in
     Modules/_sha3/cleanup.py.  Patch by Mickaël Schoentgen.

   - bpo-35619(23): Improved support of custom data descriptors in *note
     help(): 8e0. and *note pydoc: b5.

   - bpo-28503(24): The ‘crypt’ module now internally uses the
     ‘crypt_r()’ library function instead of ‘crypt()’ when available.

   - bpo-35614(25): Fixed help() on metaclasses.  Patch by Sanyam
     Khurana.

   - bpo-35568(26): Expose ‘raise(signum)’ as ‘raise_signal’

   - bpo-35588(27): The floor division and modulo operations and the
     *note divmod(): 9ac. function on *note fractions.Fraction: 1e7.
     types are 2–4x faster.  Patch by Stefan Behnel.

   - bpo-35585(28): Speed-up building enums by value, e.g.
     http.HTTPStatus(200).

   - bpo-30561(29): random.gammavariate(1.0, beta) now computes the same
     result as random.expovariate(1.0 / beta).  This synchronizes the
     two algorithms and eliminates some idiosyncrasies in the old
     implementation.  It does however produce a difference stream of
     random variables than it used to.

   - bpo-35537(30): The *note subprocess: d6. module can now use the
     *note os.posix_spawn(): 220. function in some cases for better
     performance.

   - bpo-35526(31): Delaying the ‘joke’ of barry_as_FLUFL.mandatory to
     Python version 4.0

   - bpo-35523(32): Remove *note ctypes: 2a. callback workaround: no
     longer create a callback at startup.  Avoid SELinux alert on
     ‘import ctypes’ and ‘import uuid’.

   - bpo-31784(33): *note uuid.uuid1(): bc6. now calls *note
     time.time_ns(): aff. rather than ‘int(time.time() * 1e9)’.

   - bpo-35513(34): ‘TextTestRunner’ of ‘unittest.runner’ now uses *note
     time.perf_counter(): a97. rather than *note time.time(): 254. to
     measure the execution time of a test: ‘time.time()’ can go
     backwards, whereas ‘time.perf_counter()’ is monotonic.

   - bpo-35502(35): Fixed reference leaks in *note
     xml.etree.ElementTree.TreeBuilder: a63. in case of unfinished
     building of the tree (in particular when an error was raised during
     parsing XML).

   - bpo-35348(36): Make *note platform.architecture(): 179e. parsing of
     ‘file’ command output more reliable: add the ‘-b’ option to the
     ‘file’ command to omit the filename, force the usage of the C
     locale, and search also the “shared object” pattern.

   - bpo-35491(37): *note multiprocessing: 94.: Add ‘Pool.__repr__()’
     and enhance ‘BaseProcess.__repr__()’ (add pid and parent pid) to
     ease debugging.  Pool state constant values are now strings instead
     of integers, for example ‘RUN’ value becomes ‘'RUN'’ instead of
     ‘0’.

   - bpo-35477(38): ‘multiprocessing.Pool.__enter__()’ now fails if the
     pool is not running: ‘with pool:’ fails if used more than once.

   - bpo-31446(39): Copy command line that was passed to CreateProcessW
     since this function can change the content of the input buffer.

   - bpo-35471(40): Python 2.4 dropped MacOS 9 support.  The macpath
     module was deprecated in Python 3.7.  The module is now removed.

   - bpo-23057(41): Unblock Proactor event loop when keyboard interrupt
     is received on Windows

   - bpo-35052(42): Fix xml.dom.minidom cloneNode() on a document with
     an entity: pass the correct arguments to the user data handler of
     an entity.

   - bpo-20239(43): Allow repeated assignment deletion of *note
     unittest.mock.Mock: a58. attributes.  Patch by Pablo Galindo.

   - bpo-17185(44): Set ‘__signature__’ on mock for *note inspect: 7e.
     to get signature.  Patch by Karthikeyan Singaravelan.

   - bpo-35445(45): Memory errors during creating posix.environ no
     longer ignored.

   - bpo-35415(46): Validate fileno= argument to socket.socket().

   - bpo-35424(47): ‘multiprocessing.Pool’ destructor now emits *note
     ResourceWarning: 244. if the pool is still running.

   - bpo-35330(48): When a ‘Mock’ instance was used to wrap an object,
     if ‘side_effect’ is used in one of the mocks of it methods, don’t
     call the original implementation and return the result of using the
     side effect the same way that it is done with return_value.

   - bpo-35346(49): Drop Mac OS 9 and Rhapsody support from the *note
     platform: aa. module.  Rhapsody last release was in 2000.  Mac OS 9
     last release was in 2001.

   - bpo-10496(50): ‘check_environ()’ of ‘distutils.utils’ now catches
     *note KeyError: 345. on calling *note pwd.getpwuid(): 1bc0.: don’t
     create the ‘HOME’ environment variable in this case.

   - bpo-10496(51): ‘posixpath.expanduser()’ now returns the input
     'path' unchanged if the ‘HOME’ environment variable is not set and
     the current user has no home directory (if the current user
     identifier doesn’t exist in the password database).  This change
     fix the *note site: c7. module if the current user doesn’t exist in
     the password database (if the user has no home directory).

   - bpo-35389(52): *note platform.libc_ver(): 1bc1. now uses
     ‘os.confstr('CS_GNU_LIBC_VERSION')’ if available and the
     'executable' parameter is not set.

   - bpo-35394(53): Add empty slots to asyncio abstract protocols.

   - bpo-35310(54): Fix a bug in *note select.select(): dce. where, in
     some cases, the file descriptor sequences were returned unmodified
     after a signal interruption, even though the file descriptors might
     not be ready yet.  ‘select.select()’ will now always return empty
     lists if a timeout has occurred.  Patch by Oran Avraham.

   - bpo-35380(55): Enable TCP_NODELAY on Windows for proactor asyncio
     event loop.

   - bpo-35341(56): Add generic version of ‘collections.OrderedDict’ to
     the ‘typing’ module.  Patch by Ismo Toijala.

   - bpo-35371(57): Fixed possible crash in ‘os.utime()’ on Windows when
     pass incorrect arguments.

   - bpo-35346(58): *note platform.uname(): 1bc2. now redirects ‘stderr’
     to *note os.devnull: 1bc3. when running external programs like ‘cmd
     /c ver’.

   - bpo-35066(59): Previously, calling the strftime() method on a
     datetime object with a trailing ‘%’ in the format string would
     result in an exception.  However, this only occurred when the
     datetime C module was being used; the python implementation did not
     match this behavior.  Datetime is now PEP-399 compliant, and will
     not throw an exception on a trailing ‘%’.

   - bpo-35345(60): The function ‘platform.popen’ has been removed, it
     was deprecated since Python 3.3: use *note os.popen(): a96.
     instead.

   - bpo-35344(61): On macOS, *note platform.platform(): 1869. now uses
     *note platform.mac_ver(): 1bc4, if it returns a non-empty release
     string, to get the macOS version rather than the darwin version.

   - bpo-35312(62): Make ‘lib2to3.pgen2.parse.ParseError’ round-trip
     pickle-able.  Patch by Anthony Sottile.

   - bpo-35308(63): Fix regression in ‘webbrowser’ where default
     browsers may be preferred over browsers in the ‘BROWSER’
     environment variable.

   - bpo-24746(64): Avoid stripping trailing whitespace in doctest fancy
     diff.  Original patch by R. David Murray & Jairo Trad.  Enhanced by
     Sanyam Khurana.

   - bpo-28604(65): *note locale.localeconv(): c1e. now sets temporarily
     the ‘LC_CTYPE’ locale to the ‘LC_MONETARY’ locale if the two
     locales are different and monetary strings are non-ASCII. This
     temporary change affects other threads.

   - bpo-35277(66): Update ensurepip to install pip 18.1 and setuptools
     40.6.2.

   - bpo-24209(67): Adds IPv6 support when invoking http.server
     directly.

   - bpo-35226(68): Recursively check arguments when testing for
     equality of *note unittest.mock.call: 1b5e. objects and add note
     that tracking of parameters used to create ancestors of mocks in
     ‘mock_calls’ is not possible.

   - bpo-29564(69): The warnings module now suggests to enable
     tracemalloc if the source is specified, the tracemalloc module is
     available, but tracemalloc is not tracing memory allocations.

   - bpo-35189(70): Modify the following fnctl function to retry if
     interrupted by a signal (EINTR): flock, lockf, fnctl

   - bpo-30064(71): Use add_done_callback() in sock_* asyncio API to
     unsubscribe reader/writer early on calcellation.

   - bpo-35186(72): Removed the “built with” comment added when
     ‘setup.py upload’ is used with either ‘bdist_rpm’ or ‘bdist_dumb’.

   - bpo-35152(73): Allow sending more than 2 GB at once on a
     multiprocessing connection on non-Windows systems.

   - bpo-35062(74): Fix incorrect parsing of *note
     io.IncrementalNewlineDecoder: 17d8.’s 'translate' argument.

   - bpo-35065(75): Remove ‘StreamReaderProtocol._untrack_reader’.  The
     call to ‘_untrack_reader’ is currently performed too soon, causing
     the protocol to forget about the reader before ‘connection_lost’
     can run and feed the EOF to the reader.

   - bpo-34160(76): ElementTree and minidom now preserve the attribute
     order specified by the user.

   - bpo-35079(77): Improve difflib.SequenceManager.get_matching_blocks
     doc by adding ‘non-overlapping’ and changing ‘!=’ to ‘<’.

   - bpo-33710(78): Deprecated ‘l*gettext()’ functions and methods in
     the *note gettext: 63. module.  They return encoded bytes instead
     of Unicode strings and are artifacts from Python 2 times.  Also
     deprecated functions and methods related to setting the charset for
     ‘l*gettext()’ functions and methods.

   - bpo-35017(79): *note socketserver.BaseServer.serve_forever(): 1183.
     now exits immediately if it’s *note shutdown(): 1bc5. method is
     called while it is polling for new events.

   - bpo-35024(80): ‘importlib’ no longer logs ‘wrote <bytecode path>’
     redundantly after ‘(created|could not create) <bytecode path>’ is
     already logged.  Patch by Quentin Agren.

   - bpo-35047(81): ‘unittest.mock’ now includes mock calls in exception
     messages if ‘assert_not_called’, ‘assert_called_once’, or
     ‘assert_called_once_with’ fails.  Patch by Petter Strandmark.

   - bpo-31047(82): Fix ‘ntpath.abspath’ regression where it didn’t
     remove a trailing separator on Windows.  Patch by Tim Graham.

   - bpo-35053(83): tracemalloc now tries to update the traceback when
     an object is reused from a “free list” (optimization for faster
     object creation, used by the builtin list type for example).

   - bpo-31553(84): Add the –json-lines option to json.tool.  Patch by
     hongweipeng.

   - bpo-34794(85): Fixed a leak in Tkinter when pass the Python wrapper
     around Tcl_Obj back to Tcl/Tk.

   - bpo-34909(86): Enum: fix grandchildren subclassing when parent
     mixed with concrete data types.

   - bpo-35022(87): *note unittest.mock.MagicMock: ec3. now supports the
     ‘__fspath__’ method (from *note os.PathLike: c72.).

   - bpo-35008(88): Fixed references leaks when call the
     ‘__setstate__()’ method of *note xml.etree.ElementTree.Element:
     310. in the C implementation for already initialized element.

   - bpo-23420(89): Verify the value for the parameter ‘-s’ of the
     cProfile CLI. Patch by Robert Kuska

   - bpo-33947(90): dataclasses now handle recursive reprs without
     raising RecursionError.

   - bpo-34890(91): Make *note inspect.iscoroutinefunction(): 2e4, *note
     inspect.isgeneratorfunction(): 1901. and *note
     inspect.isasyncgenfunction(): 1902. work with *note
     functools.partial(): 417.  Patch by Pablo Galindo.

   - bpo-34521(92): Use *note socket.CMSG_SPACE(): 1bc6. to calculate
     ancillary data size instead of *note socket.CMSG_LEN(): 1bc7. in
     ‘multiprocessing.reduction.recvfds()’ as RFC 3542(93) requires the
     use of the former for portable applications.

   - bpo-31522(94): The ‘mailbox.mbox.get_string’ function 'from_'
     parameter can now successfully be set to a non-default value.

   - bpo-34970(95): Protect tasks weak set manipulation in
     ‘asyncio.all_tasks()’

   - bpo-34969(96): gzip: Add –fast, –best on the gzip CLI, these
     parameters will be used for the fast compression method (quick) or
     the best method compress (slower, but smaller file).  Also, change
     the default compression level to 6 (tradeoff).

   - bpo-16965(97): The 2to3 ‘execfile’ fixer now opens the file with
     mode ‘'rb'’.  Patch by Zackery Spytz.

   - bpo-34966(98): *note pydoc: b5. now supports aliases not only to
     methods defined in the end class, but also to inherited methods.
     The docstring is not duplicated for aliases.

   - bpo-34926(99): *note mimetypes.MimeTypes.guess_type(): 1bc8. now
     accepts *note path-like object: 2a0. in addition to url strings.
     Patch by Mayank Asthana.

   - bpo-23831(100): Add ‘moveto()’ method to the ‘tkinter.Canvas’
     widget.  Patch by Juliette Monsel.

   - bpo-34941(101): Methods ‘find()’, ‘findtext()’ and ‘findall()’ of
     the ‘Element’ class in the *note xml.etree.ElementTree: 125. module
     are now able to find children which are instances of ‘Element’
     subclasses.

   - bpo-32680(102): *note smtplib.SMTP: 937. objects now always have a
     ‘sock’ attribute present

   - bpo-34769(103): Fix for async generators not finalizing when event
     loop is in debug mode and garbage collector runs in another thread.

   - bpo-34936(104): Fix ‘TclError’ in
     ‘tkinter.Spinbox.selection_element()’.  Patch by Juliette Monsel.

   - bpo-34829(105): Add methods ‘selection_from’, ‘selection_range’,
     ‘selection_present’ and ‘selection_to’ to the ‘tkinter.Spinbox’ for
     consistency with the ‘tkinter.Entry’ widget.  Patch by Juliette
     Monsel.

   - bpo-34911(106): Added 'secure_protocols' argument to
     'http.cookiejar.DefaultCookiePolicy' to allow for tweaking of
     protocols and also to add support by default for 'wss', the secure
     websocket protocol.

   - bpo-34922(107): Fixed integer overflow in the *note digest(): 1bc9.
     and *note hexdigest(): 1bca. methods for the SHAKE algorithm in the
     *note hashlib: 68. module.

   - bpo-34925(108): 25% speedup in argument parsing for the functions
     in the bisect module.

   - bpo-34900(109): Fixed *note unittest.TestCase.debug(): 19ef. when
     used to call test methods with subtests.  Patch by Bruno Oliveira.

   - bpo-34844(110): logging.Formatter enhancement - Ensure styles and
     fmt matches in logging.Formatter - Added validate method in each
     format style class: StrFormatStyle, PercentStyle,
     StringTemplateStyle.  - This method is called in the constructor of
     logging.Formatter class - Also re-raise the KeyError in the format
     method of each style class, so it would a bit clear that it’s an
     error with the invalid format fields.

   - bpo-34897(111): Adjust test.support.missing_compiler_executable
     check so that a nominal command name of “” is ignored.  Patch by
     Michael Felt.

   - bpo-34871(112): Fix inspect module polluted ‘sys.modules’ when
     parsing ‘__text_signature__’ of callable.

   - bpo-34898(113): Add ‘mtime’ argument to ‘gzip.compress’ for
     reproducible output.  Patch by Guo Ci Teo.

   - bpo-28441(114): On Cygwin and MinGW, ensure that ‘sys.executable’
     always includes the full filename in the path, including the ‘.exe’
     suffix (unless it is a symbolic link).

   - bpo-34866(115): Adding ‘max_num_fields’ to ‘cgi.FieldStorage’ to
     make DOS attacks harder by limiting the number of
     ‘MiniFieldStorage’ objects created by ‘FieldStorage’.

   - bpo-34711(116): http.server ensures it reports HTTPStatus.NOT_FOUND
     when the local path ends with “/” and is not a directory, even if
     the underlying OS (e.g.  AIX) accepts such paths as a valid file
     reference.  Patch by Michael Felt.

   - bpo-34872(117): Fix self-cancellation in C implementation of
     asyncio.Task

   - bpo-34849(118): Don’t log waiting for ‘selector.select’ in asyncio
     loop iteration.  The waiting is pretty normal for any asyncio
     program, logging its time just adds a noise to logs without any
     useful information provided.

   - bpo-34022(119): The ‘SOURCE_DATE_EPOCH’ environment variable no
     longer overrides the value of the 'invalidation_mode' argument to
     *note py_compile.compile(): a32, and determines its default value
     instead.

   - bpo-34819(120): Use a monotonic clock to compute timeouts in
     ‘Executor.map()’ and ‘as_completed()’, in order to prevent timeouts
     from deviating when the system clock is adjusted.

   - bpo-34758(121): Add .wasm -> application/wasm to list of recognized
     file types and content type headers

   - bpo-34789(122): *note xml.sax.make_parser(): 1bcb. now accepts any
     iterable as its 'parser_list' argument.  Patch by Andrés Delfino.

   - bpo-34334(123): In ‘QueueHandler’, clear ‘exc_text’ from
     ‘LogRecord’ to prevent traceback from being written twice.

   - bpo-34687(124): On Windows, asyncio now uses ProactorEventLoop,
     instead of SelectorEventLoop, by default.

   - bpo-5950(125): Support reading zip files with archive comments in
     *note zipimport: 132.

   - bpo-32892(126): The parser now represents all constants as *note
     ast.Constant: 2b9. instead of using specific constant AST types
     (‘Num’, ‘Str’, ‘Bytes’, ‘NameConstant’ and ‘Ellipsis’).  These
     classes are considered deprecated and will be removed in future
     Python versions.

   - bpo-34728(127): Add deprecation warning when ‘loop’ is used in
     methods: ‘asyncio.sleep’, ‘asyncio.wait’ and ‘asyncio.wait_for’.

   - bpo-34738(128): ZIP files created by ‘distutils’ will now include
     entries for directories.

   - bpo-34659(129): Add an optional 'initial' argument to
     itertools.accumulate().

   - bpo-29577(130): Support multiple mixin classes when creating Enums.

   - bpo-34670(131): Add SSLContext.post_handshake_auth and
     SSLSocket.verify_client_post_handshake for TLS 1.3’s post handshake
     authentication feature.

   - bpo-32718(132): The Activate.ps1 script from venv works with
     PowerShell Core 6.1 and is now available under all operating
     systems.

   - bpo-31177(133): Fix bug that prevented using *note reset_mock: d21.
     on mock instances with deleted attributes

   - bpo-34672(134): Add a workaround, so the ‘'Z'’ *note
     time.strftime(): 122e. specifier on the musl C library can work in
     some cases.

   - bpo-34666(135): Implement ‘asyncio.StreamWriter.awrite’ and
     ‘asyncio.StreamWriter.aclose()’ coroutines.  Methods are needed for
     providing a consistent stream API with control flow switched on by
     default.

   - bpo-6721(136): Acquire the logging module’s commonly used internal
     locks while fork()ing to avoid deadlocks in the child process.

   - bpo-34658(137): Fix a rare interpreter unhandled exception state
     SystemError only seen when using subprocess with a preexec_fn while
     an after_parent handler has been registered with
     os.register_at_fork and the fork system call fails.

   - bpo-34652(138): Ensure *note os.lchmod(): 21a. is never defined on
     Linux.

   - bpo-34638(139): Store a weak reference to stream reader to break
     strong references loop between reader and protocol.  It allows to
     detect and close the socket if the stream is deleted (garbage
     collected) without ‘close()’ call.

   - bpo-34536(140): ‘Enum._missing_’: raise ‘ValueError’ if None
     returned and ‘TypeError’ if non-member is returned.

   - bpo-34636(141): Speed up re scanning of many non-matching
     characters for s w and d within bytes objects.  (microoptimization)

   - bpo-24412(142): Add *note addModuleCleanup(): a59. and *note
     addClassCleanup(): a5a. to unittest to support cleanups for *note
     setUpModule(): a5b. and *note setUpClass(): a5c.  Patch by Lisa
     Roach.

   - bpo-34630(143): Don’t log SSL certificate errors in asyncio code
     (connection error logging is skipped already).

   - bpo-32490(144): Prevent filename duplication in *note subprocess:
     d6. exception messages.  Patch by Zackery Spytz.

   - bpo-34363(145): dataclasses.asdict() and .astuple() now handle
     namedtuples correctly.

   - bpo-34625(146): Update vendorized expat library version to 2.2.6.

   - bpo-32270(147): The subprocess module no longer mistakenly closes
     redirected fds even when they were in pass_fds when outside of the
     default {0, 1, 2} set.

   - bpo-34622(148): Create a dedicated ‘asyncio.CancelledError’,
     ‘asyncio.InvalidStateError’ and ‘asyncio.TimeoutError’ exception
     classes.  Inherit them from corresponding exceptions from
     ‘concurrent.futures’ package.  Extract ‘asyncio’ exceptions into a
     separate file.

   - bpo-34610(149): Fixed iterator of
     ‘multiprocessing.managers.DictProxy’.

   - bpo-34421(150): Fix distutils logging for non-ASCII strings.  This
     caused installation issues on Windows.

   - bpo-34604(151): Fix possible mojibake in the error message of
     ‘pwd.getpwnam’ and ‘grp.getgrnam’ using string representation
     because of invisible characters or trailing whitespaces.  Patch by
     William Grzybowski.

   - bpo-30977(152): Make uuid.UUID use ‘__slots__’ to reduce its memory
     footprint.  Based on original patch by Wouter Bolsterlee.

   - bpo-34574(153): OrderedDict iterators are not exhausted during
     pickling anymore.  Patch by Sergey Fedoseev.

   - bpo-8110(154): Refactored *note subprocess: d6. to check for
     Windows-specific modules rather than ‘sys.platform == 'win32'’.

   - bpo-34530(155): ‘distutils.spawn.find_executable()’ now falls back
     on *note os.defpath: 1b92. if the ‘PATH’ environment variable is
     not set.

   - bpo-34563(156): On Windows, fix multiprocessing.Connection for very
     large read: fix _winapi.PeekNamedPipe() and _winapi.ReadFile() for
     read larger than INT_MAX (usually ‘2**31-1’).

   - bpo-34558(157): Correct typo in Lib/ctypes/_aix.py

   - bpo-34282(158): Move ‘Enum._convert’ to ‘EnumMeta._convert_’ and
     fix enum members getting shadowed by parent attributes.

   - bpo-22872(159): When the queue is closed, *note ValueError: 202. is
     now raised by *note multiprocessing.Queue.put(): 1bcc. and *note
     multiprocessing.Queue.get(): 1bcd. instead of *note AssertionError:
     6ac. and *note OSError: 41a, respectively.  Patch by Zackery Spytz.

   - bpo-34515(160): Fix parsing non-ASCII identifiers in
     ‘lib2to3.pgen2.tokenize’ ( PEP 3131(161)).

   - bpo-13312(162): Avoids a possible integer underflow (undefined
     behavior) in the time module’s year handling code when passed a
     very low negative year value.

   - bpo-34472(163): Improved compatibility for streamed files in *note
     zipfile: 131.  Previously an optional signature was not being
     written and certain ZIP applications were not supported.  Patch by
     Silas Sewell.

   - bpo-34454(164): Fix the .fromisoformat() methods of datetime types
     crashing when given unicode with non-UTF-8-encodable code points.
     Specifically, datetime.fromisoformat() now accepts surrogate
     unicode code points used as the separator.  Report and tests by
     Alexey Izbyshev, patch by Paul Ganssle.

   - bpo-6700(165): Fix inspect.getsourcelines for module level
     frames/tracebacks.  Patch by Vladimir Matveev.

   - bpo-34171(166): Running the *note trace: fd. module no longer
     creates the ‘trace.cover’ file.

   - bpo-34441(167): Fix crash when an ‘ABC’-derived class with invalid
     ‘__subclasses__’ is passed as the second argument to *note
     issubclass(): 7c5.  Patch by Alexey Izbyshev.

   - bpo-34427(168): Fix infinite loop in ‘a.extend(a)’ for
     ‘MutableSequence’ subclasses.

   - bpo-34412(169): Make *note signal.strsignal(): 1bce. work on HP-UX.
     Patch by Michael Osipov.

   - bpo-20849(170): shutil.copytree now accepts a new ‘dirs_exist_ok’
     keyword argument.  Patch by Josh Bronson.

   - bpo-31715(171): Associate ‘.mjs’ file extension with
     ‘application/javascript’ MIME Type.

   - bpo-34384(172): *note os.readlink(): 929. now accepts *note
     path-like: 2a0. and *note bytes: 1c2. objects on Windows.

   - bpo-22602(173): The UTF-7 decoder now raises *note
     UnicodeDecodeError: a20. for ill-formed sequences starting with “+”
     (as specified in RFC 2152).  Patch by Zackery Spytz.

   - bpo-2122(174): The *note mmap.flush(): aad. method now returns
     ‘None’ on success, raises an exception on error under all
     platforms.

   - bpo-34341(175): Appending to the ZIP archive with the ZIP64
     extension no longer grows the size of extra fields of existing
     entries.

   - bpo-34333(176): Fix %-formatting in *note
     pathlib.PurePath.with_suffix(): 1721. when formatting an error
     message.

   - bpo-18540(177): The *note imaplib.IMAP4: 90c. and *note
     imaplib.IMAP4_SSL: 90d. classes now resolve to the local host IP
     correctly when the default value of 'host' parameter (‘''’) is
     used.

   - bpo-26502(178): Implement ‘traceback.FrameSummary.__len__()’ method
     to preserve compatibility with the old tuple API.

   - bpo-34318(179): *note assertRaises(): 530, *note
     assertRaisesRegex(): 532, *note assertWarns(): 11a8. and *note
     assertWarnsRegex(): 11a9. no longer success if the passed callable
     is None.  They no longer ignore unknown keyword arguments in the
     context manager mode.  A DeprecationWarning was raised in these
     cases since Python 3.5.

   - bpo-9372(180): Deprecate *note __getitem__(): 283. methods of *note
     xml.dom.pulldom.DOMEventStream: 738, *note
     wsgiref.util.FileWrapper: 739. and *note fileinput.FileInput: 73a.

   - bpo-33613(181): Fix a race condition in
     ‘multiprocessing.semaphore_tracker’ when the tracker receives
     SIGINT before it can register signal handlers for ignoring it.

   - bpo-34248(182): Report filename in the exception raised when the
     database file cannot be opened by *note dbm.gnu.open(): 1bcf. and
     *note dbm.ndbm.open(): 1bd0. due to OS-related error.  Patch by
     Zsolt Cserna.

   - bpo-33089(183): Add math.dist() to compute the Euclidean distance
     between two points.

   - bpo-34246(184): *note smtplib.SMTP.send_message(): e8e. no longer
     modifies the content of the 'mail_options' argument.  Patch by
     Pablo S. Blum de Aguiar.

   - bpo-31047(185): Fix ‘ntpath.abspath’ for invalid paths on windows.
     Patch by Franz Woellert.

   - bpo-32321(186): Add pure Python fallback for functools.reduce.
     Patch by Robert Wright.

   - bpo-34270(187): The default asyncio task class now always has a
     name which can be get or set using two new methods (*note
     get_name(): 9e9. and *note set_name(): 9e8.) and is visible in the
     *note repr(): 803. output.  An initial name can also be set using
     the new ‘name’ keyword argument to *note asyncio.create_task():
     1bf. or the ‘create_task()’ method of the event loop.  If no
     initial name is set, the default Task implementation generates a
     name like ‘Task-1’ using a monotonic counter.

   - bpo-34263(188): asyncio’s event loop will not pass timeouts longer
     than one day to epoll/select etc.

   - bpo-34035(189): Fix several AttributeError in zipfile seek()
     methods.  Patch by Mickaël Schoentgen.

   - bpo-32215(190): Fix performance regression in *note sqlite3: cf.
     when a DML statement appeared in a different line than the rest of
     the SQL query.

   - bpo-34075(191): Deprecate passing non-ThreadPoolExecutor instances
     to ‘AbstractEventLoop.set_default_executor()’.

   - bpo-34251(192): Restore ‘msilib.Win64’ to preserve backwards
     compatibility since it’s already used by ‘distutils’’ ‘bdist_msi’
     command.

   - bpo-19891(193): Ignore errors caused by missing / non-writable
     homedir while writing history during exit of an interactive
     session.  Patch by Anthony Sottile.

   - bpo-33089(194): Enhanced math.hypot() to support more than two
     dimensions.

   - bpo-34228(195): tracemalloc: PYTHONTRACEMALLOC=0 environment
     variable and -X tracemalloc=0 command line option are now allowed
     to disable explicitly tracemalloc at startup.

   - bpo-13041(196): Use *note shutil.get_terminal_size(): 1147. to
     calculate the terminal width correctly in the
     ‘argparse.HelpFormatter’ class.  Initial patch by Zbyszek
     Jędrzejewski-Szmek.

   - bpo-34213(197): Allow frozen dataclasses to have a field named
     “object”.  Previously this conflicted with an internal use of
     “object”.

   - bpo-34052(198): *note sqlite3.Connection.create_aggregate(): 2aa,
     *note sqlite3.Connection.create_function(): 2a9, *note
     sqlite3.Connection.set_authorizer(): 2ab, *note
     sqlite3.Connection.set_progress_handler(): 2ac. methods raises
     TypeError when unhashable objects are passed as callable.  These
     methods now don’t pass such objects to SQLite API. Previous
     behavior could lead to segfaults.  Patch by Sergey Fedoseev.

   - bpo-34197(199): Attributes 'skipinitialspace', 'doublequote' and
     'strict' of the 'dialect' attribute of the *note csv: 29. reader
     are now *note bool: 46b. instances instead of integers 0 or 1.

   - bpo-32788(200): Errors other than *note TypeError: 2c3. raised in
     methods ‘__adapt__()’ and ‘__conform__()’ in the *note sqlite3: cf.
     module are now propagated to the user.

   - bpo-21446(201): The ‘reload’ fixer now uses *note
     importlib.reload(): 51c. instead of deprecated ‘imp.reload()’.

   - bpo-940286(202): pydoc’s ‘Helper.showtopic()’ method now prints the
     cross references of a topic correctly.

   - bpo-34164(203): *note base64.b32decode(): 1060. could raise
     UnboundLocalError or OverflowError for incorrect padding.  Now it
     always raises ‘base64.Error’ in these cases.

   - bpo-33729(204): Fixed issues with arguments parsing in *note
     hashlib: 68.

   - bpo-34097(205): ZipFile can zip files older than 1980-01-01 and
     newer than 2107-12-31 using a new ‘strict_timestamps’ parameter at
     the cost of setting the timestamp to the limit.

   - bpo-34108(206): Remove extraneous CR in 2to3 refactor.

   - bpo-34070(207): Make sure to only check if the handle is a tty,
     when opening a file with ‘buffering=-1’.

   - bpo-27494(208): Reverted bpo-27494(209).  2to3 rejects now a
     trailing comma in generator expressions.

   - bpo-33967(210): functools.singledispatch now raises TypeError
     instead of IndexError when no positional arguments are passed.

   - bpo-34041(211): Add the parameter 'deterministic' to the *note
     sqlite3.Connection.create_function(): 2a9. method.  Patch by Sergey
     Fedoseev.

   - bpo-34056(212): Ensure the loader shim created by ‘imp.load_module’
     always returns bytes from its ‘get_data()’ function.  This fixes
     using ‘imp.load_module’ with PEP 552(213) hash-based pycs.

   - bpo-34054(214): The multiprocessing module now uses the monotonic
     clock *note time.monotonic(): 253. instead of the system clock
     *note time.time(): 254. to implement timeout.

   - bpo-34043(215): Optimize tarfile uncompress performance about 15%
     when gzip is used.

   - bpo-34044(216): ‘subprocess.Popen’ now copies the 'startupinfo'
     argument to leave it unchanged: it will modify the copy, so that
     the same ‘STARTUPINFO’ object can be used multiple times.

   - bpo-34010(217): Fixed a performance regression for reading streams
     with tarfile.  The buffered read should use a list, instead of
     appending to a bytes object.

   - bpo-34019(218): webbrowser: Correct the arguments passed to Opera
     Browser when opening a new URL using the ‘webbrowser’ module.
     Patch by Bumsik Kim.

   - bpo-34003(219): csv.DictReader now creates dicts instead of
     OrderedDicts.  Patch by Michael Selik.

   - bpo-33978(220): Closed existing logging handlers before
     reconfiguration via fileConfig and dictConfig.  Patch by
     Karthikeyan Singaravelan.

   - bpo-14117(221): Make minor tweaks to turtledemo.  The ‘wikipedia’
     example is now ‘rosette’, describing what it draws.  The ‘penrose’
     print output is reduced.  The’1024’ output of ‘tree’ is eliminated.

   - bpo-33974(222): Fixed passing lists and tuples of strings
     containing special characters ‘"’, ‘\’, ‘{’, ‘}’ and ‘\n’ as
     options to *note ttk: f9. widgets.

   - bpo-27500(223): Fix getaddrinfo to resolve IPv6 addresses
     correctly.

   - bpo-24567(224): Improve random.choices() to handle subnormal input
     weights that could occasionally trigger an IndexError.

   - bpo-33871(225): Fixed integer overflow in *note os.readv(): b7a,
     *note os.writev(): b7d, *note os.preadv(): b79. and *note
     os.pwritev(): b7c. and in *note os.sendfile(): b28. with 'headers'
     or 'trailers' arguments (on BSD-based OSes and macOS).

   - bpo-25007(226): Add *note copy.copy(): 537. and *note
     copy.deepcopy(): b8a. support to zlib compressors and
     decompressors.  Patch by Zackery Spytz.

   - bpo-33929(227): multiprocessing: Fix a race condition in Popen of
     multiprocessing.popen_spawn_win32.  The child process now
     duplicates the read end of pipe instead of “stealing” it.
     Previously, the read end of pipe was “stolen” by the child process,
     but it leaked a handle if the child process had been terminated
     before it could steal the handle from the parent process.

   - bpo-33899(228): Tokenize module now implicitly emits a NEWLINE when
     provided with input that does not have a trailing new line.  This
     behavior now matches what the C tokenizer does internally.
     Contributed by Ammar Askar.

   - bpo-33897(229): Added a ‘force’ keyword argument to
     logging.basicConfig().

   - bpo-33695(230): *note shutil.copytree(): a36. uses *note
     os.scandir(): a6d. function and all copy functions depending from
     it use cached *note os.stat(): 4a3. values.  The speedup for
     copying a directory with 8000 files is around +9% on Linux, +20% on
     Windows and + 30% on a Windows SMB share.  Also the number of
     ‘os.stat()’ syscalls is reduced by 38% making ‘shutil.copytree()’
     especially faster on network filesystems.  (Contributed by
     Giampaolo Rodola’ in bpo-33695(231).)

   - bpo-33916(232): bz2 and lzma: When Decompressor.__init__() is
     called twice, free the old lock to not leak memory.

   - bpo-32568(233): Make select.epoll() and its documentation
     consistent regarding 'sizehint' and 'flags'.

   - bpo-33833(234): Fixed bug in asyncio where ProactorSocketTransport
     logs AssertionError if force closed during write.

   - bpo-33663(235): Convert content length to string before putting to
     header.

   - bpo-33721(236): *note os.path: a2. functions that return a boolean
     result like *note exists(): a1b, *note lexists(): a1c, *note
     isdir(): a1d, *note isfile(): a1e, *note islink(): a19, and *note
     ismount(): a1f, and *note pathlib.Path: 229. methods that return a
     boolean result like *note exists(): a23, *note is_dir(): 230, *note
     is_file(): 22f, *note is_mount(): a24, *note is_symlink(): a25,
     *note is_block_device(): a26, *note is_char_device(): a27, *note
     is_fifo(): a28, *note is_socket(): a29. now return ‘False’ instead
     of raising *note ValueError: 202. or its subclasses *note
     UnicodeEncodeError: 67a. and *note UnicodeDecodeError: a20. for
     paths that contain characters or bytes unrepresentable at the OS
     level.

   - bpo-26544(237): Fixed implementation of *note platform.libc_ver():
     1bc1.  It almost always returned version ‘2.9’ for glibc.

   - bpo-33843(238): Remove deprecated ‘cgi.escape’, ‘cgi.parse_qs’ and
     ‘cgi.parse_qsl’.

   - bpo-33842(239): Remove ‘tarfile.filemode’ which is deprecated since
     Python 3.3.

   - bpo-30167(240): Prevent site.main() exception if PYTHONSTARTUP is
     set.  Patch by Steve Weber.

   - bpo-33805(241): Improve error message of dataclasses.replace() when
     an InitVar is not specified

   - bpo-33687(242): Fix the call to ‘os.chmod()’ for ‘uu.decode()’ if a
     mode is given or decoded.  Patch by Timo Furrer.

   - bpo-33812(243): Datetime instance d with non-None tzinfo, but with
     d.tzinfo.utcoffset(d) returning None is now treated as naive by the
     astimezone() method.

   - bpo-32108(244): In configparser, don’t clear section when it is
     assigned to itself.

   - bpo-27397(245): Make email module properly handle invalid-length
     base64 strings.

   - bpo-33578(246): Implement multibyte encoder/decoder state methods

   - bpo-30805(247): Avoid race condition with debug logging

   - bpo-33476(248): Fix _header_value_parser.py when address group is
     missing final ‘;’.  Contributed by Enrique Perez-Terron

   - bpo-33694(249): asyncio: Fix a race condition causing data loss on
     pause_reading()/resume_reading() when using the ProactorEventLoop.

   - bpo-32493(250): Correct test for ‘uuid_enc_be’ availability in
     ‘configure.ac’.  Patch by Michael Felt.

   - bpo-33792(251): Add asyncio.WindowsSelectorEventLoopPolicy and
     asyncio.WindowsProactorEventLoopPolicy.

   - bpo-33274(252): W3C DOM Level 1 specifies return value of
     Element.removeAttributeNode() as “The Attr node that was removed.”
     xml.dom.minidom now complies with this requirement.

   - bpo-33778(253): Update ‘unicodedata’’s database to Unicode version
     11.0.0.

   - bpo-33165(254): Added a stacklevel parameter to logging calls to
     allow use of wrapper/helper functions for logging APIs.

   - bpo-33770(255): improve base64 exception message for encoded inputs
     of invalid length

   - bpo-33769(256): asyncio/start_tls: Fix error message; cancel
     callbacks in case of an unhandled error; mark SSLTransport as
     closed if it is aborted.

   - bpo-33767(257): The concatenation (‘+’) and repetition (‘*’)
     sequence operations now raise *note TypeError: 2c3. instead of
     *note SystemError: 578. when performed on *note mmap.mmap: 20b.
     objects.  Patch by Zackery Spytz.

   - bpo-33734(258): asyncio/ssl: Fix AttributeError, increase default
     handshake timeout

   - bpo-31014(259): Fixed creating a controller for *note webbrowser:
     115. when a user specifies a path to an entry in the BROWSER
     environment variable.  Based on patch by John Still.

   - bpo-2504(260): Add gettext.pgettext() and variants.

   - bpo-33197(261): Add description property for _ParameterKind

   - bpo-32751(262): When cancelling the task due to a timeout, *note
     asyncio.wait_for(): 602. will now wait until the cancellation is
     complete.

   - bpo-32684(263): Fix gather to propagate cancellation of itself even
     with return_exceptions.

   - bpo-33654(264): Support protocol type switching in
     SSLTransport.set_protocol().

   - bpo-33674(265): Pause the transport as early as possible to further
     reduce the risk of data_received() being called before
     connection_made().

   - bpo-33671(266): *note shutil.copyfile(): a67, *note shutil.copy():
     a68, *note shutil.copy2(): a69, *note shutil.copytree(): a36. and
     *note shutil.move(): a6a. use platform-specific fast-copy syscalls
     on Linux and macOS in order to copy the file more efficiently.  On
     Windows ‘shutil.copyfile()’ uses a bigger default buffer size (1
     MiB instead of 16 KiB) and a *note memoryview(): 2eb.-based variant
     of *note shutil.copyfileobj(): a6b. is used.  The speedup for
     copying a 512MiB file is about +26% on Linux, +50% on macOS and
     +40% on Windows.  Also, much less CPU cycles are consumed.
     (Contributed by Giampaolo Rodola’ in bpo-25427(267).)

   - bpo-33674(268): Fix a race condition in
     SSLProtocol.connection_made() of asyncio.sslproto: start
     immediately the handshake instead of using call_soon().
     Previously, data_received() could be called before the handshake
     started, causing the handshake to hang or fail.

   - bpo-31647(269): Fixed bug where calling write_eof() on a
     _SelectorSocketTransport after it’s already closed raises
     AttributeError.

   - bpo-32610(270): Make asyncio.all_tasks() return only pending tasks.

   - bpo-32410(271): Avoid blocking on file IO in sendfile fallback code

   - bpo-33469(272): Fix RuntimeError after closing loop that used
     run_in_executor

   - bpo-33672(273): Fix Task.__repr__ crash with Cython’s bogus
     coroutines

   - bpo-33654(274): Fix transport.set_protocol() to support switching
     between asyncio.Protocol and asyncio.BufferedProtocol.  Fix
     loop.start_tls() to work with asyncio.BufferedProtocols.

   - bpo-33652(275): Pickles of type variables and subscripted generics
     are now future-proof and compatible with older Python versions.

   - bpo-32493(276): Fixed *note uuid.uuid1(): bc6. on FreeBSD.

   - bpo-33238(277): Add ‘InvalidStateError’ to *note
     concurrent.futures: 21.  ‘Future.set_result’ and
     ‘Future.set_exception’ now raise ‘InvalidStateError’ if the futures
     are not pending or running.  Patch by Jason Haydaman.

   - bpo-33618(278): Finalize and document preliminary and experimental
     TLS 1.3 support with OpenSSL 1.1.1

   - bpo-33625(279): Release GIL on ‘grp.getgrnam’, ‘grp.getgrgid’,
     ‘pwd.getpwnam’ and ‘pwd.getpwuid’ if reentrant variants of these
     functions are available.  Patch by William Grzybowski.

   - bpo-33623(280): Fix possible SIGSGV when asyncio.Future is created
     in __del__

   - bpo-11874(281): Use a better regex when breaking usage into
     wrappable parts.  Avoids bogus assertion errors from custom metavar
     strings.

   - bpo-30877(282): Fixed a bug in the Python implementation of the
     JSON decoder that prevented the cache of parsed strings from
     clearing after finishing the decoding.  Based on patch by c-fos.

   - bpo-33604(283): Remove HMAC default to md5 marked for removal in
     3.8 (removal originally planned in 3.6, bump to 3.8 in PR 7062).

   - bpo-33582(284): Emit a deprecation warning for
     inspect.formatargspec

   - bpo-21145(285): Add ‘functools.cached_property’ decorator, for
     computed properties cached for the life of the instance.

   - bpo-33570(286): Change TLS 1.3 cipher suite settings for
     compatibility with OpenSSL 1.1.1-pre6 and newer.  OpenSSL 1.1.1
     will have TLS 1.3 ciphers enabled by default.

   - bpo-28556(287): Do not simplify arguments to ‘typing.Union’.  Now
     ‘Union[Manager, Employee]’ is not simplified to ‘Employee’ at
     runtime.  Such simplification previously caused several bugs and
     limited possibilities for introspection.

   - bpo-12486(288): *note tokenize.generate_tokens(): 4dd. is now
     documented as a public API to tokenize unicode strings.  It was
     previously present but undocumented.

   - bpo-33540(289): Add a new ‘block_on_close’ class attribute to
     ‘ForkingMixIn’ and ‘ThreadingMixIn’ classes of *note socketserver:
     cd.

   - bpo-33548(290): tempfile._candidate_tempdir_list should consider
     common TEMP locations

   - bpo-33109(291): argparse subparsers are once again not required by
     default, reverting the change in behavior introduced by
     bpo-26510(292) in 3.7.0a2.

   - bpo-33541(293): Remove unused private method
     ‘_strptime.LocaleTime.__pad’ (a.k.a.  ‘_LocaleTime__pad’).

   - bpo-33536(294): dataclasses.make_dataclass now checks for invalid
     field names and duplicate fields.  Also, added a check for invalid
     field specifications.

   - bpo-33542(295): Prevent ‘uuid.get_node’ from using a DUID instead
     of a MAC on Windows.  Patch by Zvi Effron

   - bpo-26819(296): Fix race condition with
     ‘ReadTransport.resume_reading’ in Windows proactor event loop.

   - Fix failure in ‘typing.get_type_hints()’ when ClassVar was provided
     as a string forward reference.

   - bpo-33516(297): *note unittest.mock.MagicMock: ec3. now supports
     the ‘__round__’ magic method.

   - bpo-28612(298): Added support for Site Maps to urllib’s
     ‘RobotFileParser’ as *note RobotFileParser.site_maps(): 1bd1.
     Patch by Lady Red, based on patch by Peter Wirtz.

   - bpo-28167(299): Remove platform.linux_distribution, which was
     deprecated since 3.5.

   - bpo-33504(300): Switch the default dictionary implementation for
     *note configparser: 22. from *note collections.OrderedDict: 5de. to
     the standard *note dict: 256. type.

   - bpo-33505(301): Optimize asyncio.ensure_future() by reordering if
     checks: 1.17x faster.

   - bpo-33497(302): Add errors param to cgi.parse_multipart and make an
     encoding in FieldStorage use the given errors (needed for Twisted).
     Patch by Amber Brown.

   - bpo-29235(303): The ‘cProfile.Profile’ class can now be used as a
     context manager.  Patch by Scott Sanderson.

   - bpo-33495(304): Change dataclasses.Fields repr to use the repr of
     each of its members, instead of str.  This makes it more clear what
     each field actually represents.  This is especially true for the
     ‘type’ member.

   - bpo-26103(305): Correct ‘inspect.isdatadescriptor’ to look for
     ‘__set__’ or ‘__delete__’.  Patch by Aaron Hall.

   - bpo-29209(306): Removed the ‘doctype()’ method and the 'html'
     parameter of the constructor of *note XMLParser: a62.  The
     ‘doctype()’ method defined in a subclass will no longer be called.
     Deprecated methods ‘getchildren()’ and ‘getiterator()’ in the *note
     ElementTree: 125. module emit now a *note DeprecationWarning: 1a5.
     instead of *note PendingDeprecationWarning: 8d1.

   - bpo-33453(307): Fix dataclasses to work if using literal string
     type annotations or if using PEP 563 “Postponed Evaluation of
     Annotations”.  Only specific string prefixes are detected for both
     ClassVar (“ClassVar” and “typing.ClassVar”) and InitVar (“InitVar”
     and “dataclasses.InitVar”).

   - bpo-28556(308): Minor fixes in typing module: add annotations to
     ‘NamedTuple.__new__’, pass ‘*args’ and ‘**kwds’ in
     ‘Generic.__new__’.  Original PRs by Paulius Šarka and Chad
     Dombrova.

   - bpo-33365(309): Print the header values besides the header keys
     instead just the header keys if 'debuglevel' is set to >0 in *note
     http.client: 6f.  Patch by Marco Strigl.

   - bpo-20087(310): Updated alias mapping with glibc 2.27 supported
     locales.

   - bpo-33422(311): Fix trailing quotation marks getting deleted when
     looking up byte/string literals on pydoc.  Patch by Andrés Delfino.

   - bpo-28167(312): The function ‘platform.linux_distribution’ and
     ‘platform.dist’ now trigger a ‘DeprecationWarning’ and have been
     marked for removal in Python 3.8

   - bpo-33281(313): Fix ctypes.util.find_library regression on macOS.

   - bpo-33311(314): Text and html output generated by cgitb does not
     display parentheses if the current call is done directly in the
     module.  Patch by Stéphane Blondon.

   - bpo-27300(315): The file classes in 'tempfile' now accept an
     'errors' parameter that complements the already existing
     'encoding'.  Patch by Stephan Hohe.

   - bpo-32933(316): *note unittest.mock.mock_open(): 1022. now supports
     iteration over the file contents.  Patch by Tony Flury.

   - bpo-33217(317): Raise *note TypeError: 2c3. when looking up
     non-Enum objects in Enum classes and Enum members.

   - bpo-33197(318): Update error message when constructing invalid
     inspect.Parameters Patch by Donghee Na.

   - bpo-33383(319): Fixed crash in the get() method of the *note
     dbm.ndbm: 34. database object when it is called with a single
     argument.

   - bpo-33375(320): The warnings module now finds the Python file
     associated with a warning from the code object, rather than the
     frame’s global namespace.  This is consistent with how tracebacks
     and pdb find filenames, and should work better for dynamically
     executed code.

   - bpo-33336(321): ‘imaplib’ now allows ‘MOVE’ command in
     ‘IMAP4.uid()’ (RFC 6851: IMAP MOVE Extension) and potentially as a
     name of supported method of ‘IMAP4’ object.

   - bpo-32455(322): Added 'jump' parameter to *note dis.stack_effect():
     f69.

   - bpo-27485(323): Rename and deprecate undocumented functions in
     *note urllib.parse(): 10a.

   - bpo-33332(324): Add ‘signal.valid_signals()’ to expose the POSIX
     sigfillset() functionality.

   - bpo-33251(325): ‘ConfigParser.items()’ was fixed so that key-value
     pairs passed in via *note vars(): 1bd2. are not included in the
     resulting output.

   - bpo-33329(326): Fix multiprocessing regression on newer glibcs

   - bpo-33334(327): *note dis.stack_effect(): f69. now supports all
     defined opcodes including NOP and EXTENDED_ARG.

   - bpo-991266(328): Fix quoting of the ‘Comment’ attribute of *note
     http.cookies.SimpleCookie: 1bd3.

   - bpo-33131(329): Upgrade bundled version of pip to 10.0.1.

   - bpo-33308(330): Fixed a crash in the ‘parser’ module when
     converting an ST object to a tree of tuples or lists with
     ‘line_info=False’ and ‘col_info=True’.

   - bpo-23403(331): lib2to3 now uses pickle protocol 4 for pre-computed
     grammars.

   - bpo-33266(332): lib2to3 now recognizes ‘rf'...'’ strings.

   - bpo-11594(333): Ensure line-endings are respected when using
     lib2to3.

   - bpo-33254(334): Have *note importlib.resources.contents(): 1f2. and
     *note importlib.abc.ResourceReader.contents(): 1bd4. return an
     *note iterable: 126d. instead of an *note iterator: 1ac.

   - bpo-33265(335): ‘contextlib.ExitStack’ and
     ‘contextlib.AsyncExitStack’ now use a method instead of a wrapper
     function for exit callbacks.

   - bpo-33263(336): Fix FD leak in ‘_SelectorSocketTransport’ Patch by
     Vlad Starostin.

   - bpo-33256(337): Fix display of ‘<module>’ call in the html produced
     by ‘cgitb.html()’.  Patch by Stéphane Blondon.

   - bpo-33144(338): ‘random.Random()’ and its subclassing mechanism got
     optimized to check only once at class/subclass instantiation time
     whether its ‘getrandbits()’ method can be relied on by other
     methods, including ‘randrange()’, for the generation of arbitrarily
     large random integers.  Patch by Wolfgang Maier.

   - bpo-33185(339): Fixed regression when running pydoc with the *note
     -m: 5e4. switch.  (The regression was introduced in 3.7.0b3 by the
     resolution of bpo-33053(340))

     This fix also changed pydoc to add ‘os.getcwd()’ to *note sys.path:
     3b7. when necessary, rather than adding ‘"."’.

   - bpo-29613(341): Added support for the ‘SameSite’ cookie flag to the
     ‘http.cookies’ module.

   - bpo-33169(342): Delete entries of ‘None’ in *note
     sys.path_importer_cache: 5e7. when
     ‘importlib.machinery.invalidate_caches()’ is called.

   - bpo-33203(343): ‘random.Random.choice()’ now raises ‘IndexError’
     for empty sequences consistently even when called from subclasses
     without a ‘getrandbits()’ implementation.

   - bpo-33224(344): Update difflib.mdiff() for PEP 479(345).  Convert
     an uncaught StopIteration in a generator into a return-statement.

   - bpo-33209(346): End framing at the end of C implementation of *note
     pickle.Pickler.dump(): 1bd5.

   - bpo-32861(347): The urllib.robotparser’s ‘__str__’ representation
     now includes wildcard entries and the “Crawl-delay” and
     “Request-rate” fields.  Also removes extra newlines that were being
     appended to the end of the string.  Patch by Michael Lazar.

   - bpo-23403(348): ‘DEFAULT_PROTOCOL’ in *note pickle: a6. was bumped
     to 4.  Protocol 4 is described in PEP 3154(349) and available since
     Python 3.4.  It offers better performance and smaller size compared
     to protocol 3 introduced in Python 3.0.

   - bpo-20104(350): Improved error handling and fixed a reference leak
     in *note os.posix_spawn(): 220.

   - bpo-33106(351): Deleting a key from a read-only dbm database raises
     module specific error instead of KeyError.

   - bpo-33175(352): In dataclasses, Field.__set_name__ now looks up the
     __set_name__ special method on the class, not the instance, of the
     default value.

   - bpo-32380(353): Create functools.singledispatchmethod to support
     generic single dispatch on descriptors and methods.

   - bpo-33141(354): Have Field objects pass through __set_name__ to
     their default values, if they have their own __set_name__.

   - bpo-33096(355): Allow ttk.Treeview.insert to insert iid that has a
     false boolean value.  Note iid=0 and iid=False would be same.
     Patch by Garvit Khatri.

   - bpo-32873(356): Treat type variables and special typing forms as
     immutable by copy and pickle.  This fixes several minor issues and
     inconsistencies, and improves backwards compatibility with Python
     3.6.

   - bpo-33134(357): When computing dataclass’s __hash__, use the lookup
     table to contain the function which returns the __hash__ value.
     This is an improvement over looking up a string, and then testing
     that string to see what to do.

   - bpo-33127(358): The ssl module now compiles with LibreSSL 2.7.1.

   - bpo-32505(359): Raise TypeError if a member variable of a dataclass
     is of type Field, but doesn’t have a type annotation.

   - bpo-33078(360): Fix the failure on OSX caused by the tests relying
     on sem_getvalue

   - bpo-33116(361): Add ‘Field’ to dataclasses.__all__.

   - bpo-32896(362): Fix an error where subclassing a dataclass with a
     field that uses a default_factory would generate an incorrect
     class.

   - bpo-33100(363): Dataclasses: If a field has a default value that’s
     a MemberDescriptorType, then it’s from that field being in
     __slots__, not an actual default value.

   - bpo-32953(364): If a non-dataclass inherits from a frozen
     dataclass, allow attributes to be added to the derived class.  Only
     attributes from the frozen dataclass cannot be assigned to.
     Require all dataclasses in a hierarchy to be either all frozen or
     all non-frozen.

   - bpo-33097(365): Raise RuntimeError when ‘executor.submit’ is called
     during interpreter shutdown.

   - bpo-32968(366): Modulo and floor division involving Fraction and
     float should return float.

   - bpo-33061(367): Add missing ‘NoReturn’ to ‘__all__’ in typing.py

   - bpo-33078(368): Fix the size handling in multiprocessing.Queue when
     a pickling error occurs.

   - bpo-33064(369): lib2to3 now properly supports trailing commas after
     ‘*args’ and ‘**kwargs’ in function signatures.

   - bpo-33056(370): FIX properly close leaking fds in
     concurrent.futures.ProcessPoolExecutor.

   - bpo-33021(371): Release the GIL during fstat() calls, avoiding hang
     of all threads when calling mmap.mmap(), os.urandom(), and
     random.seed().  Patch by Nir Soffer.

   - bpo-31804(372): Avoid failing in multiprocessing.Process if the
     standard streams are closed or None at exit.

   - bpo-33034(373): Providing an explicit error message when casting
     the port property to anything that is not an integer value using
     ‘urlparse()’ and ‘urlsplit()’.  Patch by Matt Eaton.

   - bpo-30249(374): Improve struct.unpack_from() exception messages for
     problems with the buffer size and offset.

   - bpo-33037(375): Skip sending/receiving data after SSL transport
     closing.

   - bpo-27683(376): Fix a regression in *note ipaddress: 80. that
     result of ‘hosts()’ is empty when the network is constructed by a
     tuple containing an integer mask and only 1 bit left for addresses.

   - bpo-22674(377): Add the strsignal() function in the signal module
     that returns the system description of the given signal, as
     returned by strsignal(3).

   - bpo-32999(378): Fix C implementation of ‘ABC.__subclasscheck__(cls,
     subclass)’ crashed when ‘subclass’ is not a type object.

   - bpo-33009(379): Fix inspect.signature() for single-parameter
     partialmethods.

   - bpo-32969(380): Expose several missing constants in zlib and fix
     corresponding documentation.

   - bpo-32056(381): Improved exceptions raised for invalid number of
     channels and sample width when read an audio file in modules
     ‘aifc’, *note wave: 113. and ‘sunau’.

   - bpo-32970(382): Improved disassembly of the MAKE_FUNCTION
     instruction.

   - bpo-32844(383): Fix wrong redirection of a low descriptor (0 or 1)
     to stderr in subprocess if another low descriptor is closed.

   - bpo-32960(384): For dataclasses, disallow inheriting frozen from
     non-frozen classes, and also disallow inheriting non-frozen from
     frozen classes.  This restriction will be relaxed at a future date.

   - bpo-32713(385): Fixed tarfile.itn handling of out-of-bounds float
     values.  Patch by Joffrey Fuhrer.

   - bpo-32257(386): The ssl module now contains OP_NO_RENEGOTIATION
     constant, available with OpenSSL 1.1.0h or 1.1.1.

   - bpo-32951(387): Direct instantiation of SSLSocket and SSLObject
     objects is now prohibited.  The constructors were never documented,
     tested, or designed as public constructors.  Users were suppose to
     use ssl.wrap_socket() or SSLContext.

   - bpo-32929(388): Remove the tri-state parameter “hash”, and add the
     boolean “unsafe_hash”.  If unsafe_hash is True, add a __hash__
     function, but if a __hash__ exists, raise TypeError.  If
     unsafe_hash is False, add a __hash__ based on the values of eq= and
     frozen=.  The unsafe_hash=False behavior is the same as the old
     hash=None behavior.  unsafe_hash=False is the default, just as
     hash=None used to be.

   - bpo-32947(389): Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround
     for TLSv1.3 for future compatibility with OpenSSL 1.1.1.

   - bpo-32146(390): Document the interaction between frozen executables
     and the spawn and forkserver start methods in multiprocessing.

   - bpo-30622(391): The ssl module now detects missing NPN support in
     LibreSSL.

   - bpo-32922(392): dbm.open() now encodes filename with the filesystem
     encoding rather than default encoding.

   - bpo-32759(393): Free unused arenas in multiprocessing.heap.

   - bpo-32859(394): In ‘os.dup2’, don’t check every call whether the
     ‘dup3’ syscall exists or not.

   - bpo-32556(395): nt._getfinalpathname, nt._getvolumepathname and
     nt._getdiskusage now correctly convert from bytes.

   - bpo-21060(396): Rewrite confusing message from setup.py upload from
     “No dist file created in earlier command” to the more helpful “Must
     create and upload files in one command”.

   - bpo-32857(397): In *note tkinter: f0, ‘after_cancel(None)’ now
     raises a *note ValueError: 202. instead of canceling the first
     scheduled function.  Patch by Cheryl Sabella.

   - bpo-32852(398): Make sure sys.argv remains as a list when running
     trace.

   - bpo-31333(399): ‘_abc’ module is added.  It is a speedup module
     with C implementations for various functions and methods in ‘abc’.
     Creating an ABC subclass and calling ‘isinstance’ or ‘issubclass’
     with an ABC subclass are up to 1.5x faster.  In addition, this
     makes Python start-up up to 10% faster.

     Note that the new implementation hides internal registry and
     caches, previously accessible via private attributes
     ‘_abc_registry’, ‘_abc_cache’, and ‘_abc_negative_cache’.  There
     are three debugging helper methods that can be used instead
     ‘_dump_registry’, ‘_abc_registry_clear’, and ‘_abc_caches_clear’.

   - bpo-32841(400): Fixed ‘asyncio.Condition’ issue which silently
     ignored cancellation after notifying and cancelling a conditional
     lock.  Patch by Bar Harel.

   - bpo-32819(401): ssl.match_hostname() has been simplified and no
     longer depends on re and ipaddress module for wildcard and IP
     addresses.  Error reporting for invalid wildcards has been
     improved.

   - bpo-19675(402): ‘multiprocessing.Pool’ no longer leaks processes if
     its initialization fails.

   - bpo-32394(403): socket: Remove
     TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older
     version Windows during run-time.

   - bpo-31787(404): Fixed refleaks of ‘__init__()’ methods in various
     modules.  (Contributed by Oren Milman)

   - bpo-30157(405): Fixed guessing quote and delimiter in
     csv.Sniffer.sniff() when only the last field is quoted.  Patch by
     Jake Davis.

   - bpo-30688(406): Added support of ‘\N{name}’ escapes in regular
     expressions.  Based on patch by Jonathan Eunice.

   - bpo-32792(407): collections.ChainMap() preserves the order of the
     underlying mappings.

   - bpo-32775(408): *note fnmatch.translate(): 1bd6. no longer produces
     patterns which contain set operations.  Sets starting with ‘[’ or
     containing ‘–’, ‘&&’, ‘~~’ or ‘||’ will be interpreted differently
     in regular expressions in future versions.  Currently they emit
     warnings.  fnmatch.translate() now avoids producing patterns
     containing such sets by accident.

   - bpo-32622(409): Implement native fast sendfile for Windows proactor
     event loop.

   - bpo-32777(410): Fix a rare but potential pre-exec child process
     deadlock in subprocess on POSIX systems when marking file
     descriptors inheritable on exec in the child process.  This bug
     appears to have been introduced in 3.4.

   - bpo-32647(411): The ctypes module used to depend on indirect
     linking for dlopen.  The shared extension is now explicitly linked
     against libdl on platforms with dl.

   - bpo-32749(412): A *note dbm.dumb: 32. database opened with flags
     ‘r’ is now read-only.  *note dbm.dumb.open(): aab. with flags ‘r’
     and ‘w’ no longer creates a database if it does not exist.

   - bpo-32741(413): Implement ‘asyncio.TimerHandle.when()’ method.

   - bpo-32691(414): Use mod_spec.parent when running modules with pdb

   - bpo-32734(415): Fixed ‘asyncio.Lock()’ safety issue which allowed
     acquiring and locking the same lock multiple times, without it
     being free.  Patch by Bar Harel.

   - bpo-32727(416): Do not include name field in SMTP envelope from
     address.  Patch by Stéphane Wirtel

   - bpo-31453(417): Add TLSVersion constants and
     SSLContext.maximum_version / minimum_version attributes.  The new
     API wraps OpenSSL 1.1
     ‘https://web.archive.org/web/20180309043602/https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html’
     feature.

   - bpo-24334(418): Internal implementation details of ssl module were
     cleaned up.  The SSLSocket has one less layer of indirection.
     Owner and session information are now handled by the SSLSocket and
     SSLObject constructor.  Channel binding implementation has been
     simplified.

   - bpo-31848(419): Fix the error handling in Aifc_read.initfp() when
     the SSND chunk is not found.  Patch by Zackery Spytz.

   - bpo-32585(420): Add Ttk spinbox widget to *note tkinter.ttk: f9.
     Patch by Alan D Moore.

   - bpo-32512(421): *note profile: af. CLI accepts ‘-m module_name’ as
     an alternative to script path.

   - bpo-8525(422): help() on a type now displays builtin subclasses.
     This is intended primarily to help with notification of more
     specific exception subclasses.

     Patch by Sanyam Khurana.

   - bpo-31639(423): http.server now exposes a ThreadingHTTPServer class
     and uses it when the module is run with ‘-m’ to cope with web
     browsers pre-opening sockets.

   - bpo-29877(424): compileall: import ProcessPoolExecutor only when
     needed, preventing hangs on low resource platforms

   - bpo-32221(425): Various functions returning tuple containing IPv6
     addresses now omit ‘%scope’ part since the same information is
     already encoded in 'scopeid' tuple item.  Especially this speeds up
     ‘socket.recvfrom()’ when it receives multicast packet since useless
     resolving of network interface name is omitted.

   - bpo-32147(426): *note binascii.unhexlify(): 1bd7. is now up to 2
     times faster.  Patch by Sergey Fedoseev.

   - bpo-30693(427): The TarFile class now recurses directories in a
     reproducible way.

   - bpo-30693(428): The ZipFile class now recurses directories in a
     reproducible way.

   - bpo-31680(429): Added *note curses.ncurses_version: 9f2.

   - bpo-31908(430): Fix output of cover files for ‘trace’ module
     command-line tool.  Previously emitted cover files only when
     ‘--missing’ option was used.  Patch by Michael Selik.

   - bpo-31608(431): Raise a ‘TypeError’ instead of crashing if a
     ‘collections.deque’ subclass returns a non-deque from ‘__new__’.
     Patch by Oren Milman.

   - bpo-31425(432): Add support for sockets of the AF_QIPCRTR address
     family, supported by the Linux kernel.  This is used to communicate
     with services, such as GPS or radio, running on Qualcomm devices.
     Patch by Bjorn Andersson.

   - bpo-22005(433): Implemented unpickling instances of *note datetime:
     1cc, *note date: 1cd. and *note time: 1ce. pickled by Python 2.
     ‘encoding='latin1'’ should be used for successful decoding.

   - bpo-27645(434): *note sqlite3.Connection: 245. now exposes a *note
     backup: b98. method, if the underlying SQLite library is at version
     3.6.11 or higher.  Patch by Lele Gaifax.

   - bpo-16865(435): Support arrays >=2GiB in *note ctypes: 2a.  Patch
     by Segev Finer.

   - bpo-31508(436): Removed support of arguments in
     ‘tkinter.ttk.Treeview.selection’.  It was deprecated in 3.6.  Use
     specialized methods like ‘selection_set’ for changing the
     selection.

   - bpo-29456(437): Fix bugs in hangul normalization: u1176, u11a7 and
     u11c3

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35845

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35864

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35537

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35847

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35813

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35780

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35537

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23846

   (9) https://bugs.python.org/issue?@action=redirect&bpo=34323

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35674

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35733

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35726

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35719

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35717

   (15) https://bugs.python.org/issue?@action=redirect&bpo=35699

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32710

   (17) https://bugs.python.org/issue?@action=redirect&bpo=35702

   (18) https://bugs.python.org/issue?@action=redirect&bpo=32710

   (19) https://bugs.python.org/issue?@action=redirect&bpo=35682

   (20) https://bugs.python.org/issue?@action=redirect&bpo=35283

   (21) https://bugs.python.org/issue?@action=redirect&bpo=35664

   (22) https://bugs.python.org/issue?@action=redirect&bpo=35643

   (23) https://bugs.python.org/issue?@action=redirect&bpo=35619

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28503

   (25) https://bugs.python.org/issue?@action=redirect&bpo=35614

   (26) https://bugs.python.org/issue?@action=redirect&bpo=35568

   (27) https://bugs.python.org/issue?@action=redirect&bpo=35588

   (28) https://bugs.python.org/issue?@action=redirect&bpo=35585

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30561

   (30) https://bugs.python.org/issue?@action=redirect&bpo=35537

   (31) https://bugs.python.org/issue?@action=redirect&bpo=35526

   (32) https://bugs.python.org/issue?@action=redirect&bpo=35523

   (33) https://bugs.python.org/issue?@action=redirect&bpo=31784

   (34) https://bugs.python.org/issue?@action=redirect&bpo=35513

   (35) https://bugs.python.org/issue?@action=redirect&bpo=35502

   (36) https://bugs.python.org/issue?@action=redirect&bpo=35348

   (37) https://bugs.python.org/issue?@action=redirect&bpo=35491

   (38) https://bugs.python.org/issue?@action=redirect&bpo=35477

   (39) https://bugs.python.org/issue?@action=redirect&bpo=31446

   (40) https://bugs.python.org/issue?@action=redirect&bpo=35471

   (41) https://bugs.python.org/issue?@action=redirect&bpo=23057

   (42) https://bugs.python.org/issue?@action=redirect&bpo=35052

   (43) https://bugs.python.org/issue?@action=redirect&bpo=20239

   (44) https://bugs.python.org/issue?@action=redirect&bpo=17185

   (45) https://bugs.python.org/issue?@action=redirect&bpo=35445

   (46) https://bugs.python.org/issue?@action=redirect&bpo=35415

   (47) https://bugs.python.org/issue?@action=redirect&bpo=35424

   (48) https://bugs.python.org/issue?@action=redirect&bpo=35330

   (49) https://bugs.python.org/issue?@action=redirect&bpo=35346

   (50) https://bugs.python.org/issue?@action=redirect&bpo=10496

   (51) https://bugs.python.org/issue?@action=redirect&bpo=10496

   (52) https://bugs.python.org/issue?@action=redirect&bpo=35389

   (53) https://bugs.python.org/issue?@action=redirect&bpo=35394

   (54) https://bugs.python.org/issue?@action=redirect&bpo=35310

   (55) https://bugs.python.org/issue?@action=redirect&bpo=35380

   (56) https://bugs.python.org/issue?@action=redirect&bpo=35341

   (57) https://bugs.python.org/issue?@action=redirect&bpo=35371

   (58) https://bugs.python.org/issue?@action=redirect&bpo=35346

   (59) https://bugs.python.org/issue?@action=redirect&bpo=35066

   (60) https://bugs.python.org/issue?@action=redirect&bpo=35345

   (61) https://bugs.python.org/issue?@action=redirect&bpo=35344

   (62) https://bugs.python.org/issue?@action=redirect&bpo=35312

   (63) https://bugs.python.org/issue?@action=redirect&bpo=35308

   (64) https://bugs.python.org/issue?@action=redirect&bpo=24746

   (65) https://bugs.python.org/issue?@action=redirect&bpo=28604

   (66) https://bugs.python.org/issue?@action=redirect&bpo=35277

   (67) https://bugs.python.org/issue?@action=redirect&bpo=24209

   (68) https://bugs.python.org/issue?@action=redirect&bpo=35226

   (69) https://bugs.python.org/issue?@action=redirect&bpo=29564

   (70) https://bugs.python.org/issue?@action=redirect&bpo=35189

   (71) https://bugs.python.org/issue?@action=redirect&bpo=30064

   (72) https://bugs.python.org/issue?@action=redirect&bpo=35186

   (73) https://bugs.python.org/issue?@action=redirect&bpo=35152

   (74) https://bugs.python.org/issue?@action=redirect&bpo=35062

   (75) https://bugs.python.org/issue?@action=redirect&bpo=35065

   (76) https://bugs.python.org/issue?@action=redirect&bpo=34160

   (77) https://bugs.python.org/issue?@action=redirect&bpo=35079

   (78) https://bugs.python.org/issue?@action=redirect&bpo=33710

   (79) https://bugs.python.org/issue?@action=redirect&bpo=35017

   (80) https://bugs.python.org/issue?@action=redirect&bpo=35024

   (81) https://bugs.python.org/issue?@action=redirect&bpo=35047

   (82) https://bugs.python.org/issue?@action=redirect&bpo=31047

   (83) https://bugs.python.org/issue?@action=redirect&bpo=35053

   (84) https://bugs.python.org/issue?@action=redirect&bpo=31553

   (85) https://bugs.python.org/issue?@action=redirect&bpo=34794

   (86) https://bugs.python.org/issue?@action=redirect&bpo=34909

   (87) https://bugs.python.org/issue?@action=redirect&bpo=35022

   (88) https://bugs.python.org/issue?@action=redirect&bpo=35008

   (89) https://bugs.python.org/issue?@action=redirect&bpo=23420

   (90) https://bugs.python.org/issue?@action=redirect&bpo=33947

   (91) https://bugs.python.org/issue?@action=redirect&bpo=34890

   (92) https://bugs.python.org/issue?@action=redirect&bpo=34521

   (93) https://datatracker.ietf.org/doc/html/rfc3542.html

   (94) https://bugs.python.org/issue?@action=redirect&bpo=31522

   (95) https://bugs.python.org/issue?@action=redirect&bpo=34970

   (96) https://bugs.python.org/issue?@action=redirect&bpo=34969

   (97) https://bugs.python.org/issue?@action=redirect&bpo=16965

   (98) https://bugs.python.org/issue?@action=redirect&bpo=34966

   (99) https://bugs.python.org/issue?@action=redirect&bpo=34926

   (100) https://bugs.python.org/issue?@action=redirect&bpo=23831

   (101) https://bugs.python.org/issue?@action=redirect&bpo=34941

   (102) https://bugs.python.org/issue?@action=redirect&bpo=32680

   (103) https://bugs.python.org/issue?@action=redirect&bpo=34769

   (104) https://bugs.python.org/issue?@action=redirect&bpo=34936

   (105) https://bugs.python.org/issue?@action=redirect&bpo=34829

   (106) https://bugs.python.org/issue?@action=redirect&bpo=34911

   (107) https://bugs.python.org/issue?@action=redirect&bpo=34922

   (108) https://bugs.python.org/issue?@action=redirect&bpo=34925

   (109) https://bugs.python.org/issue?@action=redirect&bpo=34900

   (110) https://bugs.python.org/issue?@action=redirect&bpo=34844

   (111) https://bugs.python.org/issue?@action=redirect&bpo=34897

   (112) https://bugs.python.org/issue?@action=redirect&bpo=34871

   (113) https://bugs.python.org/issue?@action=redirect&bpo=34898

   (114) https://bugs.python.org/issue?@action=redirect&bpo=28441

   (115) https://bugs.python.org/issue?@action=redirect&bpo=34866

   (116) https://bugs.python.org/issue?@action=redirect&bpo=34711

   (117) https://bugs.python.org/issue?@action=redirect&bpo=34872

   (118) https://bugs.python.org/issue?@action=redirect&bpo=34849

   (119) https://bugs.python.org/issue?@action=redirect&bpo=34022

   (120) https://bugs.python.org/issue?@action=redirect&bpo=34819

   (121) https://bugs.python.org/issue?@action=redirect&bpo=34758

   (122) https://bugs.python.org/issue?@action=redirect&bpo=34789

   (123) https://bugs.python.org/issue?@action=redirect&bpo=34334

   (124) https://bugs.python.org/issue?@action=redirect&bpo=34687

   (125) https://bugs.python.org/issue?@action=redirect&bpo=5950

   (126) https://bugs.python.org/issue?@action=redirect&bpo=32892

   (127) https://bugs.python.org/issue?@action=redirect&bpo=34728

   (128) https://bugs.python.org/issue?@action=redirect&bpo=34738

   (129) https://bugs.python.org/issue?@action=redirect&bpo=34659

   (130) https://bugs.python.org/issue?@action=redirect&bpo=29577

   (131) https://bugs.python.org/issue?@action=redirect&bpo=34670

   (132) https://bugs.python.org/issue?@action=redirect&bpo=32718

   (133) https://bugs.python.org/issue?@action=redirect&bpo=31177

   (134) https://bugs.python.org/issue?@action=redirect&bpo=34672

   (135) https://bugs.python.org/issue?@action=redirect&bpo=34666

   (136) https://bugs.python.org/issue?@action=redirect&bpo=6721

   (137) https://bugs.python.org/issue?@action=redirect&bpo=34658

   (138) https://bugs.python.org/issue?@action=redirect&bpo=34652

   (139) https://bugs.python.org/issue?@action=redirect&bpo=34638

   (140) https://bugs.python.org/issue?@action=redirect&bpo=34536

   (141) https://bugs.python.org/issue?@action=redirect&bpo=34636

   (142) https://bugs.python.org/issue?@action=redirect&bpo=24412

   (143) https://bugs.python.org/issue?@action=redirect&bpo=34630

   (144) https://bugs.python.org/issue?@action=redirect&bpo=32490

   (145) https://bugs.python.org/issue?@action=redirect&bpo=34363

   (146) https://bugs.python.org/issue?@action=redirect&bpo=34625

   (147) https://bugs.python.org/issue?@action=redirect&bpo=32270

   (148) https://bugs.python.org/issue?@action=redirect&bpo=34622

   (149) https://bugs.python.org/issue?@action=redirect&bpo=34610

   (150) https://bugs.python.org/issue?@action=redirect&bpo=34421

   (151) https://bugs.python.org/issue?@action=redirect&bpo=34604

   (152) https://bugs.python.org/issue?@action=redirect&bpo=30977

   (153) https://bugs.python.org/issue?@action=redirect&bpo=34574

   (154) https://bugs.python.org/issue?@action=redirect&bpo=8110

   (155) https://bugs.python.org/issue?@action=redirect&bpo=34530

   (156) https://bugs.python.org/issue?@action=redirect&bpo=34563

   (157) https://bugs.python.org/issue?@action=redirect&bpo=34558

   (158) https://bugs.python.org/issue?@action=redirect&bpo=34282

   (159) https://bugs.python.org/issue?@action=redirect&bpo=22872

   (160) https://bugs.python.org/issue?@action=redirect&bpo=34515

   (161) https://peps.python.org/pep-3131/

   (162) https://bugs.python.org/issue?@action=redirect&bpo=13312

   (163) https://bugs.python.org/issue?@action=redirect&bpo=34472

   (164) https://bugs.python.org/issue?@action=redirect&bpo=34454

   (165) https://bugs.python.org/issue?@action=redirect&bpo=6700

   (166) https://bugs.python.org/issue?@action=redirect&bpo=34171

   (167) https://bugs.python.org/issue?@action=redirect&bpo=34441

   (168) https://bugs.python.org/issue?@action=redirect&bpo=34427

   (169) https://bugs.python.org/issue?@action=redirect&bpo=34412

   (170) https://bugs.python.org/issue?@action=redirect&bpo=20849

   (171) https://bugs.python.org/issue?@action=redirect&bpo=31715

   (172) https://bugs.python.org/issue?@action=redirect&bpo=34384

   (173) https://bugs.python.org/issue?@action=redirect&bpo=22602

   (174) https://bugs.python.org/issue?@action=redirect&bpo=2122

   (175) https://bugs.python.org/issue?@action=redirect&bpo=34341

   (176) https://bugs.python.org/issue?@action=redirect&bpo=34333

   (177) https://bugs.python.org/issue?@action=redirect&bpo=18540

   (178) https://bugs.python.org/issue?@action=redirect&bpo=26502

   (179) https://bugs.python.org/issue?@action=redirect&bpo=34318

   (180) https://bugs.python.org/issue?@action=redirect&bpo=9372

   (181) https://bugs.python.org/issue?@action=redirect&bpo=33613

   (182) https://bugs.python.org/issue?@action=redirect&bpo=34248

   (183) https://bugs.python.org/issue?@action=redirect&bpo=33089

   (184) https://bugs.python.org/issue?@action=redirect&bpo=34246

   (185) https://bugs.python.org/issue?@action=redirect&bpo=31047

   (186) https://bugs.python.org/issue?@action=redirect&bpo=32321

   (187) https://bugs.python.org/issue?@action=redirect&bpo=34270

   (188) https://bugs.python.org/issue?@action=redirect&bpo=34263

   (189) https://bugs.python.org/issue?@action=redirect&bpo=34035

   (190) https://bugs.python.org/issue?@action=redirect&bpo=32215

   (191) https://bugs.python.org/issue?@action=redirect&bpo=34075

   (192) https://bugs.python.org/issue?@action=redirect&bpo=34251

   (193) https://bugs.python.org/issue?@action=redirect&bpo=19891

   (194) https://bugs.python.org/issue?@action=redirect&bpo=33089

   (195) https://bugs.python.org/issue?@action=redirect&bpo=34228

   (196) https://bugs.python.org/issue?@action=redirect&bpo=13041

   (197) https://bugs.python.org/issue?@action=redirect&bpo=34213

   (198) https://bugs.python.org/issue?@action=redirect&bpo=34052

   (199) https://bugs.python.org/issue?@action=redirect&bpo=34197

   (200) https://bugs.python.org/issue?@action=redirect&bpo=32788

   (201) https://bugs.python.org/issue?@action=redirect&bpo=21446

   (202) https://bugs.python.org/issue?@action=redirect&bpo=940286

   (203) https://bugs.python.org/issue?@action=redirect&bpo=34164

   (204) https://bugs.python.org/issue?@action=redirect&bpo=33729

   (205) https://bugs.python.org/issue?@action=redirect&bpo=34097

   (206) https://bugs.python.org/issue?@action=redirect&bpo=34108

   (207) https://bugs.python.org/issue?@action=redirect&bpo=34070

   (208) https://bugs.python.org/issue?@action=redirect&bpo=27494

   (209) https://bugs.python.org/issue?@action=redirect&bpo=27494

   (210) https://bugs.python.org/issue?@action=redirect&bpo=33967

   (211) https://bugs.python.org/issue?@action=redirect&bpo=34041

   (212) https://bugs.python.org/issue?@action=redirect&bpo=34056

   (213) https://peps.python.org/pep-0552/

   (214) https://bugs.python.org/issue?@action=redirect&bpo=34054

   (215) https://bugs.python.org/issue?@action=redirect&bpo=34043

   (216) https://bugs.python.org/issue?@action=redirect&bpo=34044

   (217) https://bugs.python.org/issue?@action=redirect&bpo=34010

   (218) https://bugs.python.org/issue?@action=redirect&bpo=34019

   (219) https://bugs.python.org/issue?@action=redirect&bpo=34003

   (220) https://bugs.python.org/issue?@action=redirect&bpo=33978

   (221) https://bugs.python.org/issue?@action=redirect&bpo=14117

   (222) https://bugs.python.org/issue?@action=redirect&bpo=33974

   (223) https://bugs.python.org/issue?@action=redirect&bpo=27500

   (224) https://bugs.python.org/issue?@action=redirect&bpo=24567

   (225) https://bugs.python.org/issue?@action=redirect&bpo=33871

   (226) https://bugs.python.org/issue?@action=redirect&bpo=25007

   (227) https://bugs.python.org/issue?@action=redirect&bpo=33929

   (228) https://bugs.python.org/issue?@action=redirect&bpo=33899

   (229) https://bugs.python.org/issue?@action=redirect&bpo=33897

   (230) https://bugs.python.org/issue?@action=redirect&bpo=33695

   (231) https://bugs.python.org/issue?@action=redirect&bpo=33695

   (232) https://bugs.python.org/issue?@action=redirect&bpo=33916

   (233) https://bugs.python.org/issue?@action=redirect&bpo=32568

   (234) https://bugs.python.org/issue?@action=redirect&bpo=33833

   (235) https://bugs.python.org/issue?@action=redirect&bpo=33663

   (236) https://bugs.python.org/issue?@action=redirect&bpo=33721

   (237) https://bugs.python.org/issue?@action=redirect&bpo=26544

   (238) https://bugs.python.org/issue?@action=redirect&bpo=33843

   (239) https://bugs.python.org/issue?@action=redirect&bpo=33842

   (240) https://bugs.python.org/issue?@action=redirect&bpo=30167

   (241) https://bugs.python.org/issue?@action=redirect&bpo=33805

   (242) https://bugs.python.org/issue?@action=redirect&bpo=33687

   (243) https://bugs.python.org/issue?@action=redirect&bpo=33812

   (244) https://bugs.python.org/issue?@action=redirect&bpo=32108

   (245) https://bugs.python.org/issue?@action=redirect&bpo=27397

   (246) https://bugs.python.org/issue?@action=redirect&bpo=33578

   (247) https://bugs.python.org/issue?@action=redirect&bpo=30805

   (248) https://bugs.python.org/issue?@action=redirect&bpo=33476

   (249) https://bugs.python.org/issue?@action=redirect&bpo=33694

   (250) https://bugs.python.org/issue?@action=redirect&bpo=32493

   (251) https://bugs.python.org/issue?@action=redirect&bpo=33792

   (252) https://bugs.python.org/issue?@action=redirect&bpo=33274

   (253) https://bugs.python.org/issue?@action=redirect&bpo=33778

   (254) https://bugs.python.org/issue?@action=redirect&bpo=33165

   (255) https://bugs.python.org/issue?@action=redirect&bpo=33770

   (256) https://bugs.python.org/issue?@action=redirect&bpo=33769

   (257) https://bugs.python.org/issue?@action=redirect&bpo=33767

   (258) https://bugs.python.org/issue?@action=redirect&bpo=33734

   (259) https://bugs.python.org/issue?@action=redirect&bpo=31014

   (260) https://bugs.python.org/issue?@action=redirect&bpo=2504

   (261) https://bugs.python.org/issue?@action=redirect&bpo=33197

   (262) https://bugs.python.org/issue?@action=redirect&bpo=32751

   (263) https://bugs.python.org/issue?@action=redirect&bpo=32684

   (264) https://bugs.python.org/issue?@action=redirect&bpo=33654

   (265) https://bugs.python.org/issue?@action=redirect&bpo=33674

   (266) https://bugs.python.org/issue?@action=redirect&bpo=33671

   (267) https://bugs.python.org/issue?@action=redirect&bpo=25427

   (268) https://bugs.python.org/issue?@action=redirect&bpo=33674

   (269) https://bugs.python.org/issue?@action=redirect&bpo=31647

   (270) https://bugs.python.org/issue?@action=redirect&bpo=32610

   (271) https://bugs.python.org/issue?@action=redirect&bpo=32410

   (272) https://bugs.python.org/issue?@action=redirect&bpo=33469

   (273) https://bugs.python.org/issue?@action=redirect&bpo=33672

   (274) https://bugs.python.org/issue?@action=redirect&bpo=33654

   (275) https://bugs.python.org/issue?@action=redirect&bpo=33652

   (276) https://bugs.python.org/issue?@action=redirect&bpo=32493

   (277) https://bugs.python.org/issue?@action=redirect&bpo=33238

   (278) https://bugs.python.org/issue?@action=redirect&bpo=33618

   (279) https://bugs.python.org/issue?@action=redirect&bpo=33625

   (280) https://bugs.python.org/issue?@action=redirect&bpo=33623

   (281) https://bugs.python.org/issue?@action=redirect&bpo=11874

   (282) https://bugs.python.org/issue?@action=redirect&bpo=30877

   (283) https://bugs.python.org/issue?@action=redirect&bpo=33604

   (284) https://bugs.python.org/issue?@action=redirect&bpo=33582

   (285) https://bugs.python.org/issue?@action=redirect&bpo=21145

   (286) https://bugs.python.org/issue?@action=redirect&bpo=33570

   (287) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (288) https://bugs.python.org/issue?@action=redirect&bpo=12486

   (289) https://bugs.python.org/issue?@action=redirect&bpo=33540

   (290) https://bugs.python.org/issue?@action=redirect&bpo=33548

   (291) https://bugs.python.org/issue?@action=redirect&bpo=33109

   (292) https://bugs.python.org/issue?@action=redirect&bpo=26510

   (293) https://bugs.python.org/issue?@action=redirect&bpo=33541

   (294) https://bugs.python.org/issue?@action=redirect&bpo=33536

   (295) https://bugs.python.org/issue?@action=redirect&bpo=33542

   (296) https://bugs.python.org/issue?@action=redirect&bpo=26819

   (297) https://bugs.python.org/issue?@action=redirect&bpo=33516

   (298) https://bugs.python.org/issue?@action=redirect&bpo=28612

   (299) https://bugs.python.org/issue?@action=redirect&bpo=28167

   (300) https://bugs.python.org/issue?@action=redirect&bpo=33504

   (301) https://bugs.python.org/issue?@action=redirect&bpo=33505

   (302) https://bugs.python.org/issue?@action=redirect&bpo=33497

   (303) https://bugs.python.org/issue?@action=redirect&bpo=29235

   (304) https://bugs.python.org/issue?@action=redirect&bpo=33495

   (305) https://bugs.python.org/issue?@action=redirect&bpo=26103

   (306) https://bugs.python.org/issue?@action=redirect&bpo=29209

   (307) https://bugs.python.org/issue?@action=redirect&bpo=33453

   (308) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (309) https://bugs.python.org/issue?@action=redirect&bpo=33365

   (310) https://bugs.python.org/issue?@action=redirect&bpo=20087

   (311) https://bugs.python.org/issue?@action=redirect&bpo=33422

   (312) https://bugs.python.org/issue?@action=redirect&bpo=28167

   (313) https://bugs.python.org/issue?@action=redirect&bpo=33281

   (314) https://bugs.python.org/issue?@action=redirect&bpo=33311

   (315) https://bugs.python.org/issue?@action=redirect&bpo=27300

   (316) https://bugs.python.org/issue?@action=redirect&bpo=32933

   (317) https://bugs.python.org/issue?@action=redirect&bpo=33217

   (318) https://bugs.python.org/issue?@action=redirect&bpo=33197

   (319) https://bugs.python.org/issue?@action=redirect&bpo=33383

   (320) https://bugs.python.org/issue?@action=redirect&bpo=33375

   (321) https://bugs.python.org/issue?@action=redirect&bpo=33336

   (322) https://bugs.python.org/issue?@action=redirect&bpo=32455

   (323) https://bugs.python.org/issue?@action=redirect&bpo=27485

   (324) https://bugs.python.org/issue?@action=redirect&bpo=33332

   (325) https://bugs.python.org/issue?@action=redirect&bpo=33251

   (326) https://bugs.python.org/issue?@action=redirect&bpo=33329

   (327) https://bugs.python.org/issue?@action=redirect&bpo=33334

   (328) https://bugs.python.org/issue?@action=redirect&bpo=991266

   (329) https://bugs.python.org/issue?@action=redirect&bpo=33131

   (330) https://bugs.python.org/issue?@action=redirect&bpo=33308

   (331) https://bugs.python.org/issue?@action=redirect&bpo=23403

   (332) https://bugs.python.org/issue?@action=redirect&bpo=33266

   (333) https://bugs.python.org/issue?@action=redirect&bpo=11594

   (334) https://bugs.python.org/issue?@action=redirect&bpo=33254

   (335) https://bugs.python.org/issue?@action=redirect&bpo=33265

   (336) https://bugs.python.org/issue?@action=redirect&bpo=33263

   (337) https://bugs.python.org/issue?@action=redirect&bpo=33256

   (338) https://bugs.python.org/issue?@action=redirect&bpo=33144

   (339) https://bugs.python.org/issue?@action=redirect&bpo=33185

   (340) https://bugs.python.org/issue?@action=redirect&bpo=33053

   (341) https://bugs.python.org/issue?@action=redirect&bpo=29613

   (342) https://bugs.python.org/issue?@action=redirect&bpo=33169

   (343) https://bugs.python.org/issue?@action=redirect&bpo=33203

   (344) https://bugs.python.org/issue?@action=redirect&bpo=33224

   (345) https://peps.python.org/pep-0479/

   (346) https://bugs.python.org/issue?@action=redirect&bpo=33209

   (347) https://bugs.python.org/issue?@action=redirect&bpo=32861

   (348) https://bugs.python.org/issue?@action=redirect&bpo=23403

   (349) https://peps.python.org/pep-3154/

   (350) https://bugs.python.org/issue?@action=redirect&bpo=20104

   (351) https://bugs.python.org/issue?@action=redirect&bpo=33106

   (352) https://bugs.python.org/issue?@action=redirect&bpo=33175

   (353) https://bugs.python.org/issue?@action=redirect&bpo=32380

   (354) https://bugs.python.org/issue?@action=redirect&bpo=33141

   (355) https://bugs.python.org/issue?@action=redirect&bpo=33096

   (356) https://bugs.python.org/issue?@action=redirect&bpo=32873

   (357) https://bugs.python.org/issue?@action=redirect&bpo=33134

   (358) https://bugs.python.org/issue?@action=redirect&bpo=33127

   (359) https://bugs.python.org/issue?@action=redirect&bpo=32505

   (360) https://bugs.python.org/issue?@action=redirect&bpo=33078

   (361) https://bugs.python.org/issue?@action=redirect&bpo=33116

   (362) https://bugs.python.org/issue?@action=redirect&bpo=32896

   (363) https://bugs.python.org/issue?@action=redirect&bpo=33100

   (364) https://bugs.python.org/issue?@action=redirect&bpo=32953

   (365) https://bugs.python.org/issue?@action=redirect&bpo=33097

   (366) https://bugs.python.org/issue?@action=redirect&bpo=32968

   (367) https://bugs.python.org/issue?@action=redirect&bpo=33061

   (368) https://bugs.python.org/issue?@action=redirect&bpo=33078

   (369) https://bugs.python.org/issue?@action=redirect&bpo=33064

   (370) https://bugs.python.org/issue?@action=redirect&bpo=33056

   (371) https://bugs.python.org/issue?@action=redirect&bpo=33021

   (372) https://bugs.python.org/issue?@action=redirect&bpo=31804

   (373) https://bugs.python.org/issue?@action=redirect&bpo=33034

   (374) https://bugs.python.org/issue?@action=redirect&bpo=30249

   (375) https://bugs.python.org/issue?@action=redirect&bpo=33037

   (376) https://bugs.python.org/issue?@action=redirect&bpo=27683

   (377) https://bugs.python.org/issue?@action=redirect&bpo=22674

   (378) https://bugs.python.org/issue?@action=redirect&bpo=32999

   (379) https://bugs.python.org/issue?@action=redirect&bpo=33009

   (380) https://bugs.python.org/issue?@action=redirect&bpo=32969

   (381) https://bugs.python.org/issue?@action=redirect&bpo=32056

   (382) https://bugs.python.org/issue?@action=redirect&bpo=32970

   (383) https://bugs.python.org/issue?@action=redirect&bpo=32844

   (384) https://bugs.python.org/issue?@action=redirect&bpo=32960

   (385) https://bugs.python.org/issue?@action=redirect&bpo=32713

   (386) https://bugs.python.org/issue?@action=redirect&bpo=32257

   (387) https://bugs.python.org/issue?@action=redirect&bpo=32951

   (388) https://bugs.python.org/issue?@action=redirect&bpo=32929

   (389) https://bugs.python.org/issue?@action=redirect&bpo=32947

   (390) https://bugs.python.org/issue?@action=redirect&bpo=32146

   (391) https://bugs.python.org/issue?@action=redirect&bpo=30622

   (392) https://bugs.python.org/issue?@action=redirect&bpo=32922

   (393) https://bugs.python.org/issue?@action=redirect&bpo=32759

   (394) https://bugs.python.org/issue?@action=redirect&bpo=32859

   (395) https://bugs.python.org/issue?@action=redirect&bpo=32556

   (396) https://bugs.python.org/issue?@action=redirect&bpo=21060

   (397) https://bugs.python.org/issue?@action=redirect&bpo=32857

   (398) https://bugs.python.org/issue?@action=redirect&bpo=32852

   (399) https://bugs.python.org/issue?@action=redirect&bpo=31333

   (400) https://bugs.python.org/issue?@action=redirect&bpo=32841

   (401) https://bugs.python.org/issue?@action=redirect&bpo=32819

   (402) https://bugs.python.org/issue?@action=redirect&bpo=19675

   (403) https://bugs.python.org/issue?@action=redirect&bpo=32394

   (404) https://bugs.python.org/issue?@action=redirect&bpo=31787

   (405) https://bugs.python.org/issue?@action=redirect&bpo=30157

   (406) https://bugs.python.org/issue?@action=redirect&bpo=30688

   (407) https://bugs.python.org/issue?@action=redirect&bpo=32792

   (408) https://bugs.python.org/issue?@action=redirect&bpo=32775

   (409) https://bugs.python.org/issue?@action=redirect&bpo=32622

   (410) https://bugs.python.org/issue?@action=redirect&bpo=32777

   (411) https://bugs.python.org/issue?@action=redirect&bpo=32647

   (412) https://bugs.python.org/issue?@action=redirect&bpo=32749

   (413) https://bugs.python.org/issue?@action=redirect&bpo=32741

   (414) https://bugs.python.org/issue?@action=redirect&bpo=32691

   (415) https://bugs.python.org/issue?@action=redirect&bpo=32734

   (416) https://bugs.python.org/issue?@action=redirect&bpo=32727

   (417) https://bugs.python.org/issue?@action=redirect&bpo=31453

   (418) https://bugs.python.org/issue?@action=redirect&bpo=24334

   (419) https://bugs.python.org/issue?@action=redirect&bpo=31848

   (420) https://bugs.python.org/issue?@action=redirect&bpo=32585

   (421) https://bugs.python.org/issue?@action=redirect&bpo=32512

   (422) https://bugs.python.org/issue?@action=redirect&bpo=8525

   (423) https://bugs.python.org/issue?@action=redirect&bpo=31639

   (424) https://bugs.python.org/issue?@action=redirect&bpo=29877

   (425) https://bugs.python.org/issue?@action=redirect&bpo=32221

   (426) https://bugs.python.org/issue?@action=redirect&bpo=32147

   (427) https://bugs.python.org/issue?@action=redirect&bpo=30693

   (428) https://bugs.python.org/issue?@action=redirect&bpo=30693

   (429) https://bugs.python.org/issue?@action=redirect&bpo=31680

   (430) https://bugs.python.org/issue?@action=redirect&bpo=31908

   (431) https://bugs.python.org/issue?@action=redirect&bpo=31608

   (432) https://bugs.python.org/issue?@action=redirect&bpo=31425

   (433) https://bugs.python.org/issue?@action=redirect&bpo=22005

   (434) https://bugs.python.org/issue?@action=redirect&bpo=27645

   (435) https://bugs.python.org/issue?@action=redirect&bpo=16865

   (436) https://bugs.python.org/issue?@action=redirect&bpo=31508

   (437) https://bugs.python.org/issue?@action=redirect&bpo=29456


File: python.info,  Node: Documentation<54>,  Next: Tests<56>,  Prev: Library<138>,  Up: Python 3 8 0 alpha 1

1.23.63.4 Documentation
.......................

   - bpo-21257(1): Document *note http.client.parse_headers(): 1bd9.

   - bpo-34764(2): Improve example of iter() with 2nd sentinel argument.

   - bpo-35564(3): Explicitly set master_doc variable in conf.py for
     compliance with Sphinx 2.0

   - bpo-35511(4): Specified that profile.Profile class doesn’t not
     support enable or disable methods.  Also, elaborated that Profile
     object as a context manager is only supported in cProfile module.

   - bpo-10536(5): Enhance the gettext docs.  Patch by Éric Araujo

   - bpo-35089(6): Remove mention of ‘typing.io’ and ‘typing.re’.  Their
     types should be imported from ‘typing’ directly.

   - bpo-35038(7): Fix the documentation about an unexisting
     ‘f_restricted’ attribute in the frame object.  Patch by Stéphane
     Wirtel

   - bpo-35042(8): Replace PEP XYZ by the pep role and allow to use the
     direct links to the PEPs.

   - bpo-35044(9): Fix the documentation with the role ‘exc’ for the
     appropriated exception.  Patch by Stéphane Wirtel

   - bpo-35035(10): Rename documentation for *note email.utils: 50. to
     ‘email.utils.rst’.

   - bpo-34967(11): Use app.add_object_type() instead of the deprecated
     Sphinx function app.description_unit()

   - bpo-34913(12): Add documentation about the new command line
     interface of the gzip module.

   - bpo-32174(13): chm document displays non-ASCII characters properly
     on some MBCS Windows systems.

   - bpo-11233(14): Create availability directive for documentation.
     Original patch by Georg Brandl.

   - bpo-34790(15): Document how passing coroutines to asyncio.wait()
     can be confusing.

   - bpo-34552(16): Make clear that ‘==’ operator sometimes is
     equivalent to ‘is’.  The ‘<’, ‘<=’, ‘>’ and ‘>=’ operators are only
     defined where they make sense.

   - bpo-28617(17): Fixed info in the stdtypes docs concerning the types
     that support membership tests.

   - bpo-20177(18): Migrate datetime.date.fromtimestamp to Argument
     Clinic.  Patch by Tim Hoffmann.

   - bpo-34065(19): Fix wrongly written basicConfig documentation markup
     syntax

   - bpo-33460(20): replaced ellipsis with correct error codes in
     tutorial chapter 3.

   - bpo-33847(21): Add ‘@’ operator entry to index.

   - bpo-33409(22): Clarified the relationship between PEP 538(23)’s
     PYTHONCOERCECLOCALE and PEP 540’s PYTHONUTF8 mode.

   - bpo-33197(24): Add versionadded tag to the documentation of
     ParameterKind.description

   - bpo-17045(25): Improve the C-API doc for PyTypeObject.  This
     includes adding several quick-reference tables and a lot of missing
     slot/typedef entries.  The existing entries were also cleaned up
     with a slightly more consistent format.

   - bpo-33736(26): Improve the documentation of *note
     asyncio.open_connection(): b31, *note asyncio.start_server(): b32.
     and their UNIX socket counterparts.

   - bpo-23859(27): Document that ‘asyncio.wait()’ does not cancel its
     futures on timeout.

   - bpo-32436(28): Document PEP 567(29) changes to asyncio.

   - bpo-33604(30): Update HMAC md5 default to a DeprecationWarning,
     bump removal to 3.8.

   - bpo-33594(31): Document ‘getargspec’, ‘from_function’ and
     ‘from_builtin’ as deprecated in their respective docstring, and
     include version since deprecation in DeprecationWarning message.

   - bpo-33503(32): Fix broken pypi link

   - bpo-33421(33): Add missing documentation for
     ‘typing.AsyncContextManager’.

   - bpo-33487(34): BZ2file now emit a DeprecationWarning when
     buffering=None is passed, the deprecation message and documentation
     also now explicitly state it is deprecated since 3.0.

   - bpo-33378(35): Add Korean language switcher for
     ‘https://docs.python.org/3/’

   - bpo-33276(36): Clarify that the ‘__path__’ attribute on modules
     cannot be just any value.

   - bpo-33201(37): Modernize documentation for writing C extension
     types.

   - bpo-33195(38): Deprecate ‘Py_UNICODE’ usage in ‘c-api/arg’
     document.  ‘Py_UNICODE’ related APIs are deprecated since Python
     3.3, but it is missed in the document.

   - bpo-33126(39): Document PyBuffer_ToContiguous().

   - bpo-27212(40): Modify documentation for the ‘islice()’ recipe to
     consume initial values up to the start index.

   - bpo-28247(41): Update *note zipapp: 130. documentation to describe
     how to make standalone applications.

   - bpo-18802(42): Documentation changes for ipaddress.  Patch by Jon
     Foster and Berker Peksag.

   - bpo-27428(43): Update documentation to clarify that
     ‘WindowsRegistryFinder’ implements ‘MetaPathFinder’.  (Patch by
     Himanshu Lakhara)

   - bpo-28124(44): The ssl module function ssl.wrap_socket() has been
     de-emphasized and deprecated in favor of the more secure and
     efficient SSLContext.wrap_socket() method.

   - bpo-17232(45): Clarify docs for -O and -OO. Patch by Terry Reedy.

   - bpo-32436(46): Add documentation for the contextvars module (PEP
     567).

   - bpo-32800(47): Update link to w3c doc for xml default namespaces.

   - bpo-11015(48): Update *note test.support: e4. documentation.

   - bpo-32613(49): Update the faq/windows.html to use the py command
     from PEP 397 instead of python.

   - bpo-8722(50): Document ‘__getattr__()’ behavior when property
     ‘get()’ method raises *note AttributeError: 34e.

   - bpo-32614(51): Modify RE examples in documentation to use raw
     strings to prevent *note DeprecationWarning: 1a5. and add text to
     REGEX HOWTO to highlight the deprecation.

   - bpo-20709(52): Remove the paragraph where we explain that
     os.utime() does not support a directory as path under Windows.
     Patch by Jan-Philip Gehrcke

   - bpo-32722(53): Remove the bad example in the tutorial of the
     Generator Expression.  Patch by Stéphane Wirtel

   - bpo-31972(54): Improve docstrings for ‘pathlib.PurePath’
     subclasses.

   - bpo-30607(55): Use the externalized ‘python-docs-theme’ package
     when building the documentation.

   - bpo-8243(56): Add a note about curses.addch and curses.addstr
     exception behavior when writing outside a window, or pad.

   - bpo-32337(57): Update documentation related with ‘dict’ order.

   - bpo-25041(58): Document ‘AF_PACKET’ in the *note socket: cc.
     module.

   - bpo-31432(59): Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
     CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21257

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34764

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35564

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35511

   (5) https://bugs.python.org/issue?@action=redirect&bpo=10536

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35089

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35038

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35042

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35044

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35035

   (11) https://bugs.python.org/issue?@action=redirect&bpo=34967

   (12) https://bugs.python.org/issue?@action=redirect&bpo=34913

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32174

   (14) https://bugs.python.org/issue?@action=redirect&bpo=11233

   (15) https://bugs.python.org/issue?@action=redirect&bpo=34790

   (16) https://bugs.python.org/issue?@action=redirect&bpo=34552

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28617

   (18) https://bugs.python.org/issue?@action=redirect&bpo=20177

   (19) https://bugs.python.org/issue?@action=redirect&bpo=34065

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33460

   (21) https://bugs.python.org/issue?@action=redirect&bpo=33847

   (22) https://bugs.python.org/issue?@action=redirect&bpo=33409

   (23) https://peps.python.org/pep-0538/

   (24) https://bugs.python.org/issue?@action=redirect&bpo=33197

   (25) https://bugs.python.org/issue?@action=redirect&bpo=17045

   (26) https://bugs.python.org/issue?@action=redirect&bpo=33736

   (27) https://bugs.python.org/issue?@action=redirect&bpo=23859

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (29) https://peps.python.org/pep-0567/

   (30) https://bugs.python.org/issue?@action=redirect&bpo=33604

   (31) https://bugs.python.org/issue?@action=redirect&bpo=33594

   (32) https://bugs.python.org/issue?@action=redirect&bpo=33503

   (33) https://bugs.python.org/issue?@action=redirect&bpo=33421

   (34) https://bugs.python.org/issue?@action=redirect&bpo=33487

   (35) https://bugs.python.org/issue?@action=redirect&bpo=33378

   (36) https://bugs.python.org/issue?@action=redirect&bpo=33276

   (37) https://bugs.python.org/issue?@action=redirect&bpo=33201

   (38) https://bugs.python.org/issue?@action=redirect&bpo=33195

   (39) https://bugs.python.org/issue?@action=redirect&bpo=33126

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27212

   (41) https://bugs.python.org/issue?@action=redirect&bpo=28247

   (42) https://bugs.python.org/issue?@action=redirect&bpo=18802

   (43) https://bugs.python.org/issue?@action=redirect&bpo=27428

   (44) https://bugs.python.org/issue?@action=redirect&bpo=28124

   (45) https://bugs.python.org/issue?@action=redirect&bpo=17232

   (46) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (47) https://bugs.python.org/issue?@action=redirect&bpo=32800

   (48) https://bugs.python.org/issue?@action=redirect&bpo=11015

   (49) https://bugs.python.org/issue?@action=redirect&bpo=32613

   (50) https://bugs.python.org/issue?@action=redirect&bpo=8722

   (51) https://bugs.python.org/issue?@action=redirect&bpo=32614

   (52) https://bugs.python.org/issue?@action=redirect&bpo=20709

   (53) https://bugs.python.org/issue?@action=redirect&bpo=32722

   (54) https://bugs.python.org/issue?@action=redirect&bpo=31972

   (55) https://bugs.python.org/issue?@action=redirect&bpo=30607

   (56) https://bugs.python.org/issue?@action=redirect&bpo=8243

   (57) https://bugs.python.org/issue?@action=redirect&bpo=32337

   (58) https://bugs.python.org/issue?@action=redirect&bpo=25041

   (59) https://bugs.python.org/issue?@action=redirect&bpo=31432


File: python.info,  Node: Tests<56>,  Next: Build<60>,  Prev: Documentation<54>,  Up: Python 3 8 0 alpha 1

1.23.63.5 Tests
...............

   - bpo-35772(1): Fix sparse file tests of test_tarfile on ppc64 with
     the tmpfs filesystem.  Fix the function testing if the filesystem
     supports sparse files: create a file which contains data and
     “holes”, instead of creating a file which contains no data.  tmpfs
     effective block size is a page size (tmpfs lives in the page
     cache).  RHEL uses 64 KiB pages on aarch64, ppc64, ppc64le, only
     s390x and x86_64 use 4 KiB pages, whereas the test punch holes of 4
     KiB.

   - bpo-35045(2): Make ssl tests less strict and also accept TLSv1 as
     system default.  The changes unbreaks test_min_max_version on
     Fedora 29.

   - bpo-32710(3): ‘test_asyncio/test_sendfile.py’ now resets the event
     loop policy using ‘tearDownModule()’ as done in other tests, to
     prevent a warning when running tests on Windows.

   - bpo-33717(4): test.pythoninfo now logs information of all clocks,
     not only time.time() and time.perf_counter().

   - bpo-35488(5): Add a test to pathlib’s Path.match() to verify it
     does not support glob-style ** recursive pattern matching.

   - bpo-31731(6): Fix a race condition in ‘check_interrupted_write()’
     of test_io: create directly the thread with SIGALRM signal blocked,
     rather than blocking the signal later from the thread.  Previously,
     it was possible that the thread gets the signal before the signal
     is blocked.

   - bpo-35424(7): Fix test_multiprocessing_main_handling: use
     ‘multiprocessing.Pool’ with a context manager and then explicitly
     join the pool.

   - bpo-35519(8): Rename ‘test.bisect’ module to ‘test.bisect_cmd’ to
     avoid conflict with *note bisect: 11. module when running directly
     a test like ‘./python Lib/test/test_xmlrpc.py’.

   - bpo-35513(9): Replace *note time.time(): 254. with *note
     time.monotonic(): 253. in tests to measure time delta.

   - bpo-34279(10): ‘test.support.run_unittest()’ no longer raise
     ‘TestDidNotRun’ if the test result contains skipped tests.  The
     exception is now only raised if no test have been run and no test
     have been skipped.

   - bpo-35412(11): Add testcase to ‘test_future4’: check unicode
     literal.

   - bpo-26704(12): Added test demonstrating double-patching of an
     instance method.  Patch by Anthony Sottile.

   - bpo-33725(13): test_multiprocessing_fork may crash on recent
     versions of macOS. Until the issue is resolved, skip the test on
     macOS.

   - bpo-35352(14): Modify test_asyncio to use the certificate set from
     the test directory.

   - bpo-35317(15): Fix ‘mktime()’ overflow error in ‘test_email’: run
     ‘test_localtime_daylight_true_dst_true()’ and
     ‘test_localtime_daylight_false_dst_true()’ with a specific
     timezone.

   - bpo-21263(16): After several reports that test_gdb does not work
     properly on macOS and since gdb is not shipped by default anymore,
     test_gdb is now skipped on macOS when LLVM Clang has been used to
     compile Python.  Patch by Lysandros Nikolaou

   - bpo-34279(17): regrtest issue a warning when no tests have been
     executed in a particular test file.  Also, a new final result state
     is issued if no test have been executed across all test files.
     Patch by Pablo Galindo.

   - bpo-34962(18): make docstest in Doc now passes., and is enforced in
     CI

   - bpo-23596(19): Use argparse for the command line of the gzip
     module.  Patch by Antony Lee

   - bpo-34537(20): Fix ‘test_gdb.test_strings()’ when ‘LC_ALL=C’ and
     GDB was compiled with Python 3.6 or earlier.

   - bpo-34587(21): test_socket: Remove RDSTest.testCongestion().  The
     test tries to fill the receiver’s socket buffer and expects an
     error.  But the RDS protocol doesn’t require that.  Moreover, the
     Linux implementation of RDS expects that the producer of the
     messages reduces its rate, it’s not the role of the receiver to
     trigger an error.  The test fails on Fedora 28 by design, so just
     remove it.

   - bpo-34661(22): Fix test_shutil if unzip doesn’t support -t.

   - bpo-34200(23): Fixed non-deterministic flakiness of test_pkg by not
     using the scary test.support.module_cleanup() logic to save and
     restore sys.modules contents between test cases.

   - bpo-34569(24): The experimental PEP 554 data channels now correctly
     pass negative PyLong objects between subinterpreters on 32-bit
     systems.  Patch by Michael Felt.

   - bpo-34594(25): Fix usage of hardcoded ‘errno’ values in the tests.

   - bpo-34579(26): Fix test_embed for AIX Patch by Michael Felt

   - bpo-34542(27): Use 3072 RSA keys and SHA-256 signature for test
     certs and keys.

   - bpo-11193(28): Remove special condition for AIX in
     ‘test_subprocess.test_undecodable_env’

   - bpo-34347(29): Fix ‘test_utf8_mode.test_cmd_line’ for AIX

   - bpo-34490(30): On AIX with AF_UNIX family sockets getsockname()
     does not provide ‘sockname’, so skip calls to
     transport.get_extra_info(‘sockname’)

   - bpo-34391(31): Fix ftplib test for TLS 1.3 by reading from data
     socket.

   - bpo-11192(32): Fix ‘test_socket’ on AIX 6.1 and later IPv6 zone id
     supports only supported by ‘inet_pton6_zone()’.  Switch to
     runtime-based ‘platform.system()’ to establish current platform
     rather than build-time based ‘sys.platform()’

   - bpo-34399(33): Update all RSA keys and DH params to use at least
     2048 bits.

   - bpo-34373(34): Fix ‘test_mktime’ and ‘test_pthread_getcpuclickid’
     tests for AIX Add range checking for ‘_PyTime_localtime’ for AIX
     Patch by Michael Felt

   - bpo-11191(35): Skip the distutils test ‘test_search_cpp’ when using
     XLC as compiler patch by aixtools (Michael Felt)

   - Improved an error message when mock assert_has_calls fails.

   - bpo-33746(36): Fix test_unittest when run in verbose mode.

   - bpo-33901(37): Fix test_dbm_gnu on macOS with gdbm 1.15: add a
     larger value to make sure that the file size changes.

   - bpo-33873(38): Fix a bug in ‘regrtest’ that caused an extra test to
     run if –huntrleaks/-R was used.  Exit with error in case that
     invalid parameters are specified to –huntrleaks/-R (at least one
     warmup run and one repetition must be used).

   - bpo-33562(39): Check that a global asyncio event loop policy is not
     left behind by any tests.

   - bpo-33655(40): Ignore test_posix_fallocate failures on BSD
     platforms that might be due to running on ZFS.

   - bpo-32962(41): Fixed test_gdb when Python is compiled with flags
     -mcet -fcf-protection -O0.

   - bpo-33358(42): Fix
     ‘test_embed.test_pre_initialization_sys_options()’ when the
     interpreter is built with ‘--enable-shared’.

   - bpo-32872(43): Avoid regrtest compatibility issue with namespace
     packages.

   - bpo-32517(44): Fix failing ‘test_asyncio’ on macOS 10.12.2+ due to
     transport of ‘KqueueSelector’ loop was not being closed.

   - bpo-32663(45): Making sure the ‘SMTPUTF8SimTests’ class of tests
     gets run in ‘test_smtplib.py’.

   - bpo-27643(46): Test_C test case needs “signed short” bitfields, but
     the IBM XLC compiler (on AIX) does not support this Skip the code
     and test when AIX and XLC are used

     Applicable to Python2-2.7 and later

   - bpo-19417(47): Add test_bdb.py.

   - bpo-31809(48): Add tests to verify connection with secp ECDH
     curves.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35772

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35045

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32710

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33717

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35488

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31731

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35424

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35519

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35513

   (10) https://bugs.python.org/issue?@action=redirect&bpo=34279

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35412

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26704

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33725

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35352

   (15) https://bugs.python.org/issue?@action=redirect&bpo=35317

   (16) https://bugs.python.org/issue?@action=redirect&bpo=21263

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34279

   (18) https://bugs.python.org/issue?@action=redirect&bpo=34962

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23596

   (20) https://bugs.python.org/issue?@action=redirect&bpo=34537

   (21) https://bugs.python.org/issue?@action=redirect&bpo=34587

   (22) https://bugs.python.org/issue?@action=redirect&bpo=34661

   (23) https://bugs.python.org/issue?@action=redirect&bpo=34200

   (24) https://bugs.python.org/issue?@action=redirect&bpo=34569

   (25) https://bugs.python.org/issue?@action=redirect&bpo=34594

   (26) https://bugs.python.org/issue?@action=redirect&bpo=34579

   (27) https://bugs.python.org/issue?@action=redirect&bpo=34542

   (28) https://bugs.python.org/issue?@action=redirect&bpo=11193

   (29) https://bugs.python.org/issue?@action=redirect&bpo=34347

   (30) https://bugs.python.org/issue?@action=redirect&bpo=34490

   (31) https://bugs.python.org/issue?@action=redirect&bpo=34391

   (32) https://bugs.python.org/issue?@action=redirect&bpo=11192

   (33) https://bugs.python.org/issue?@action=redirect&bpo=34399

   (34) https://bugs.python.org/issue?@action=redirect&bpo=34373

   (35) https://bugs.python.org/issue?@action=redirect&bpo=11191

   (36) https://bugs.python.org/issue?@action=redirect&bpo=33746

   (37) https://bugs.python.org/issue?@action=redirect&bpo=33901

   (38) https://bugs.python.org/issue?@action=redirect&bpo=33873

   (39) https://bugs.python.org/issue?@action=redirect&bpo=33562

   (40) https://bugs.python.org/issue?@action=redirect&bpo=33655

   (41) https://bugs.python.org/issue?@action=redirect&bpo=32962

   (42) https://bugs.python.org/issue?@action=redirect&bpo=33358

   (43) https://bugs.python.org/issue?@action=redirect&bpo=32872

   (44) https://bugs.python.org/issue?@action=redirect&bpo=32517

   (45) https://bugs.python.org/issue?@action=redirect&bpo=32663

   (46) https://bugs.python.org/issue?@action=redirect&bpo=27643

   (47) https://bugs.python.org/issue?@action=redirect&bpo=19417

   (48) https://bugs.python.org/issue?@action=redirect&bpo=31809


File: python.info,  Node: Build<60>,  Next: Windows<53>,  Prev: Tests<56>,  Up: Python 3 8 0 alpha 1

1.23.63.6 Build
...............

   - bpo-34691(1): The _contextvars module is now built into the core
     Python library on Windows.

   - bpo-35683(2): Improved Azure Pipelines build steps and now
     verifying layouts correctly

   - bpo-35642(3): Remove asynciomodule.c from pythoncore.vcxproj

   - bpo-35550(4): Fix incorrect Solaris #ifdef checks to look for __sun
     && __SVR4 instead of sun when compiling.

   - bpo-35499(5): ‘make profile-opt’ no longer replaces ‘CFLAGS_NODIST’
     with ‘CFLAGS’.  It now adds profile-guided optimization (PGO) flags
     to ‘CFLAGS_NODIST’: existing ‘CFLAGS_NODIST’ flags are kept.

   - bpo-35257(6): Avoid leaking the linker flags from Link Time
     Optimizations (LTO) into distutils when compiling C extensions.

   - bpo-35351(7): When building Python with clang and LTO, LTO flags
     are no longer passed into CFLAGS to build third-party C extensions
     through distutils.

   - bpo-35139(8): Fix a compiler error when statically linking
     ‘pyexpat’ in ‘Modules/Setup’.

   - bpo-35059(9): PCbuild: Set InlineFunctionExpansion to
     OnlyExplicitInline (“/Ob1” option) in pyproject.props in Debug mode
     to expand functions marked as inline.  This change should make
     Python compiled in Debug mode a little bit faster on Windows.

   - bpo-35011(10): Restores the use of pyexpatns.h to isolate our
     embedded copy of the expat C library so that its symbols do not
     conflict at link or dynamic loading time with an embedding
     application or other extension modules with their own version of
     libexpat.

   - bpo-28015(11): Have –with-lto works correctly with clang.

   - bpo-34765(12): Update the outdated install-sh file to the latest
     revision from automake v1.16.1

   - bpo-34585(13): Check for floating-point byte order in configure.ac
     using compilation tests instead of executing code, so that these
     checks work in cross-compiled builds.

   - bpo-34710(14): Fixed SSL module build with OpenSSL & pedantic
     CFLAGS.

   - bpo-34582(15): Add JUnit XML output for regression tests and update
     Azure DevOps builds.

   - bpo-34081(16): Make Sphinx warnings as errors in the Docs Makefile.

   - bpo-34555(17): Fix for case where it was not possible to have both
     ‘HAVE_LINUX_VM_SOCKETS_H’ and ‘HAVE_SOCKADDR_ALG’ be undefined.

   - bpo-33015(18): Fix an undefined behaviour in the pthread
     implementation of *note PyThread_start_new_thread(): 1bdc.: add a
     function wrapper to always return ‘NULL’.

   - bpo-34245(19): The Python shared library is now installed with
     write permission (mode 0755), which is the standard way of
     installing such libraries.

   - bpo-34121(20): Fix detection of C11 atomic support on clang.

   - bpo-32430(21): Rename Modules/Setup.dist to Modules/Setup, and
     remove the necessity to copy the former manually to the latter when
     updating the local source tree.

   - bpo-30345(22): Add -g to LDFLAGS when compiling with LTO to get
     debug symbols.

   - bpo-5755(23): Move ‘-Wstrict-prototypes’ option to ‘CFLAGS_NODIST’
     from ‘OPT’.  This option emitted annoying warnings when building
     extension modules written in C++.

   - bpo-33614(24): Ensures module definition files for the stable ABI
     on Windows are correctly regenerated.

   - bpo-33648(25): The –with-c-locale-warning configuration flag has
     been removed.  It has had no effect for about a year.

   - bpo-33522(26): Enable CI builds on Visual Studio Team Services at
     ‘https://python.visualstudio.com/cpython’

   - bpo-33512(27): configure’s check for “long double” has been
     simplified

   - bpo-33483(28): C compiler is now correctly detected from the
     standard environment variables.  –without-gcc and –with-icc options
     have been removed.

   - bpo-33394(29): Enable the verbose build for extension modules, when
     GNU make is passed macros on the command line.

   - bpo-33393(30): Update config.guess and config.sub files.

   - bpo-33377(31): Add new triplets for mips r6 and riscv variants
     (used in extension suffixes).

   - bpo-32232(32): By default, modules configured in ‘Modules/Setup’
     are no longer built with ‘-DPy_BUILD_CORE’.  Instead, modules that
     specifically need that preprocessor definition include it in their
     individual entries.

   - bpo-33182(33): The embedding tests can once again be built with
     clang 6.0

   - bpo-33163(34): Upgrade pip to 9.0.3 and setuptools to v39.0.1.

   - bpo-33012(35): gcc 8 has added a new warning heuristic to detect
     invalid function casts and a stock python build seems to hit that
     warning quite often.  The most common is the cast of a METH_NOARGS
     function (that uses just one argument) to a PyCFunction.  Fix this
     by adding a dummy argument to all functions that implement
     METH_NOARGS.

   - bpo-32898(36): Fix the python debug build when using COUNT_ALLOCS.

   - bpo-29442(37): Replace optparse with argparse in setup.py

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34691

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35683

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35642

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35550

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35499

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35257

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35351

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35139

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35059

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35011

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28015

   (12) https://bugs.python.org/issue?@action=redirect&bpo=34765

   (13) https://bugs.python.org/issue?@action=redirect&bpo=34585

   (14) https://bugs.python.org/issue?@action=redirect&bpo=34710

   (15) https://bugs.python.org/issue?@action=redirect&bpo=34582

   (16) https://bugs.python.org/issue?@action=redirect&bpo=34081

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34555

   (18) https://bugs.python.org/issue?@action=redirect&bpo=33015

   (19) https://bugs.python.org/issue?@action=redirect&bpo=34245

   (20) https://bugs.python.org/issue?@action=redirect&bpo=34121

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32430

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30345

   (23) https://bugs.python.org/issue?@action=redirect&bpo=5755

   (24) https://bugs.python.org/issue?@action=redirect&bpo=33614

   (25) https://bugs.python.org/issue?@action=redirect&bpo=33648

   (26) https://bugs.python.org/issue?@action=redirect&bpo=33522

   (27) https://bugs.python.org/issue?@action=redirect&bpo=33512

   (28) https://bugs.python.org/issue?@action=redirect&bpo=33483

   (29) https://bugs.python.org/issue?@action=redirect&bpo=33394

   (30) https://bugs.python.org/issue?@action=redirect&bpo=33393

   (31) https://bugs.python.org/issue?@action=redirect&bpo=33377

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32232

   (33) https://bugs.python.org/issue?@action=redirect&bpo=33182

   (34) https://bugs.python.org/issue?@action=redirect&bpo=33163

   (35) https://bugs.python.org/issue?@action=redirect&bpo=33012

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32898

   (37) https://bugs.python.org/issue?@action=redirect&bpo=29442


File: python.info,  Node: Windows<53>,  Next: macOS<42>,  Prev: Build<60>,  Up: Python 3 8 0 alpha 1

1.23.63.7 Windows
.................

   - bpo-35890(1): Fix API calling consistency of GetVersionEx and
     wcstok.

   - bpo-32560(2): The ‘py’ launcher now forwards its ‘STARTUPINFO’
     structure to child processes.

   - bpo-35854(3): Fix EnvBuilder and –symlinks in venv on Windows

   - bpo-35811(4): Avoid propagating venv settings when launching via
     py.exe

   - bpo-35797(5): Fix default executable used by the multiprocessing
     module

   - bpo-35758(6): Allow building on ARM with MSVC.

   - bpo-29734(7): Fix handle leaks in os.stat on Windows.

   - bpo-35596(8): Use unchecked PYCs for the embeddable distro to avoid
     zipimport restrictions.

   - bpo-35596(9): Fix vcruntime140.dll being added to embeddable distro
     multiple times.

   - bpo-35402(10): Update Windows build to use Tcl and Tk 8.6.9

   - bpo-35401(11): Updates Windows build to OpenSSL 1.1.0j

   - bpo-34977(12): venv on Windows will now use a python.exe redirector
     rather than copying the actual binaries from the base environment.

   - bpo-34977(13): Adds support for building a Windows App Store
     package

   - bpo-35067(14): Remove _distutils_findvs module and use vswhere.exe
     instead.

   - bpo-32557(15): Allow shutil.disk_usage to take a file path on
     Windows

   - bpo-34770(16): Fix a possible null pointer dereference in
     pyshellext.cpp.

   - bpo-34603(17): Fix returning structs from functions produced by
     MSVC

   - bpo-34581(18): Guard MSVC-specific code in socketmodule.c with
     ‘#ifdef _MSC_VER’.

   - bpo-34532(19): Fixes exit code of list version arguments for
     py.exe.

   - bpo-34062(20): Fixed the ‘–list’ and ‘–list-paths’ arguments for
     the py.exe launcher

   - bpo-34225(21): Ensure INCLUDE and LIB directories do not end with a
     backslash.

   - bpo-34011(22): A suite of code has been changed which copied across
     DLLs and init.tcl from the running Python location into a venv
     being created.  These copies are needed only when running from a
     Python source build, and the copying code is now only run when that
     is the case, rather than whenever a venv is created.

   - bpo-34006(23): Revert line length limit for Windows help docs.  The
     line-length limit is not needed because the pages appear in a
     separate app rather than on a browser tab.  It can also interact
     badly with the DPI setting.

   - bpo-31546(24): Restore running PyOS_InputHook while waiting for
     user input at the prompt.  The restores integration of interactive
     GUI windows (such as Matplotlib figures) with the prompt on
     Windows.

   - bpo-30237(25): Output error when ReadConsole is canceled by
     CancelSynchronousIo instead of crashing.

   - bpo-33895(26): GIL is released while calling functions that acquire
     Windows loader lock.

   - bpo-33720(27): Reduces maximum marshal recursion depth on release
     builds.

   - bpo-29097(28): Fix bug where ‘datetime.fromtimestamp()’ erroneously
     throws an *note OSError: 41a. on Windows for values between 0 and
     86400.  Patch by Ammar Askar.

   - bpo-33316(29): PyThread_release_lock always fails

   - bpo-33184(30): Update Windows installer to use OpenSSL 1.1.0h.

   - bpo-32890(31): Fix usage of GetLastError() instead of errno in
     os.execve() and os.truncate().

   - bpo-33016(32): Fix potential use of uninitialized memory in
     nt._getfinalpathname

   - bpo-32903(33): Fix a memory leak in os.chdir() on Windows if the
     current directory is set to a UNC path.

   - bpo-32901(34): Update Tcl and Tk versions to 8.6.8

   - bpo-31966(35): Fixed WindowsConsoleIO.write() for writing empty
     data.

   - bpo-32409(36): Ensures activate.bat can handle Unicode contents.

   - bpo-32457(37): Improves handling of denormalized executable path
     when launching Python.

   - bpo-32370(38): Use the correct encoding for ipconfig output in the
     uuid module.  Patch by Segev Finer.

   - bpo-29248(39): Fix *note os.readlink(): 929. on Windows, which was
     mistakenly treating the ‘PrintNameOffset’ field of the reparse data
     buffer as a number of characters instead of bytes.  Patch by Craig
     Holmquist and SSE4.

   - bpo-1104(40): Correctly handle string length in
     ‘msilib.SummaryInfo.GetProperty()’ to prevent it from truncating
     the last character.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35890

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32560

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35854

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35811

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35797

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35758

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29734

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35596

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35596

   (10) https://bugs.python.org/issue?@action=redirect&bpo=35402

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35401

   (12) https://bugs.python.org/issue?@action=redirect&bpo=34977

   (13) https://bugs.python.org/issue?@action=redirect&bpo=34977

   (14) https://bugs.python.org/issue?@action=redirect&bpo=35067

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32557

   (16) https://bugs.python.org/issue?@action=redirect&bpo=34770

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34603

   (18) https://bugs.python.org/issue?@action=redirect&bpo=34581

   (19) https://bugs.python.org/issue?@action=redirect&bpo=34532

   (20) https://bugs.python.org/issue?@action=redirect&bpo=34062

   (21) https://bugs.python.org/issue?@action=redirect&bpo=34225

   (22) https://bugs.python.org/issue?@action=redirect&bpo=34011

   (23) https://bugs.python.org/issue?@action=redirect&bpo=34006

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31546

   (25) https://bugs.python.org/issue?@action=redirect&bpo=30237

   (26) https://bugs.python.org/issue?@action=redirect&bpo=33895

   (27) https://bugs.python.org/issue?@action=redirect&bpo=33720

   (28) https://bugs.python.org/issue?@action=redirect&bpo=29097

   (29) https://bugs.python.org/issue?@action=redirect&bpo=33316

   (30) https://bugs.python.org/issue?@action=redirect&bpo=33184

   (31) https://bugs.python.org/issue?@action=redirect&bpo=32890

   (32) https://bugs.python.org/issue?@action=redirect&bpo=33016

   (33) https://bugs.python.org/issue?@action=redirect&bpo=32903

   (34) https://bugs.python.org/issue?@action=redirect&bpo=32901

   (35) https://bugs.python.org/issue?@action=redirect&bpo=31966

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32409

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32457

   (38) https://bugs.python.org/issue?@action=redirect&bpo=32370

   (39) https://bugs.python.org/issue?@action=redirect&bpo=29248

   (40) https://bugs.python.org/issue?@action=redirect&bpo=1104


File: python.info,  Node: macOS<42>,  Next: IDLE<41>,  Prev: Windows<53>,  Up: Python 3 8 0 alpha 1

1.23.63.8 macOS
...............

   - bpo-35401(1): Update macOS installer to use OpenSSL 1.1.0j.

   - bpo-35025(2): Properly guard the use of the ‘CLOCK_GETTIME’ et al.
     macros in ‘timemodule’ on macOS.

   - bpo-24658(3): On macOS, fix reading from and writing into a file
     with a size larger than 2 GiB.

   - bpo-34405(4): Update to OpenSSL 1.1.0i for macOS installer builds.

   - bpo-33635(5): In macOS stat on some file descriptors (/dev/fd/3
     f.e) will result in bad file descriptor OSError.  Guard against
     this exception was added in is_dir, is_file and similar methods.
     DirEntry.is_dir can also throw this exception so
     _RecursiveWildcardSelector._iterate_directories was also extended
     with the same error ignoring pattern.

   - bpo-13631(6): The .editrc file in user’s home directory is now
     processed correctly during the readline initialization through
     editline emulation on macOS.

   - bpo-33184(7): Update macOS installer build to use OpenSSL 1.1.0h.

   - bpo-32726(8): Build and link with private copy of Tcl/Tk 8.6 for
     the macOS 10.6+ installer.  The 10.9+ installer variant already
     does this.  This means that the Python 3.7 provided by the
     python.org macOS installers no longer need or use any external
     versions of Tcl/Tk, either system-provided or user-installed, such
     as ActiveTcl.

   - bpo-32901(9): Update macOS 10.9+ installer to Tcl/Tk 8.6.8.

   - bpo-31903(10): In ‘_scproxy’, drop the GIL when calling into
     ‘SystemConfiguration’ to avoid deadlocks.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35401

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35025

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24658

   (4) https://bugs.python.org/issue?@action=redirect&bpo=34405

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33635

   (6) https://bugs.python.org/issue?@action=redirect&bpo=13631

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33184

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32726

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32901

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31903


File: python.info,  Node: IDLE<41>,  Next: Tools/Demos<30>,  Prev: macOS<42>,  Up: Python 3 8 0 alpha 1

1.23.63.9 IDLE
..............

   - bpo-35770(1): IDLE macosx deletes Options => Configure IDLE. It
     previously deleted Window => Zoom Height by mistake.  (Zoom Height
     is now on the Options menu).  On Mac, the settings dialog is
     accessed via Preferences on the IDLE menu.

   - bpo-35769(2): Change IDLE’s new file name from ‘Untitled’ to
     ‘untitled’

   - bpo-35660(3): Fix imports in idlelib.window.

   - bpo-35641(4): Proper format ‘calltip’ when the function has no
     docstring.

   - bpo-33987(5): Use ttk Frame for ttk widgets.

   - bpo-34055(6): Fix erroneous ‘smart’ indents and newlines in IDLE
     Shell.

   - bpo-35591(7): Find Selection now works when selection not found.

   - bpo-35196(8): Speed up squeezer line counting.

   - bpo-35598(9): Update config_key: use PEP 8 names and ttk widgets,
     make some objects global, and add tests.

   - bpo-28097(10): Add Previous/Next History entries to Shell menu.

   - bpo-35208(11): Squeezer now properly counts wrapped lines before
     newlines.

   - bpo-35555(12): Gray out Code Context menu entry when it’s not
     applicable.

   - bpo-35521(13): Document the IDLE editor code context feature.  Add
     some internal references within the IDLE doc.

   - bpo-22703(14): The Code Context menu label now toggles between
     Show/Hide Code Context.  The Zoom Height menu now toggles between
     Zoom/Restore Height.  Zoom Height has moved from the Window menu to
     the Options menu.

   - bpo-35213(15): Where appropriate, use ‘macOS’ in idlelib.

   - bpo-34864(16): On macOS, warn if the system preference “Prefer tabs
     when opening documents” is set to “Always”.

   - bpo-34864(17): Document two IDLE on MacOS issues.  The System
     Preferences Dock “prefer tabs always” setting disables some IDLE
     features.  Menus are a bit different than as described for Windows
     and Linux.

   - bpo-35202(18): Remove unused imports from lib/idlelib

   - bpo-33000(19): Document that IDLE’s shell has no line limit.  A
     program that runs indefinitely can overfill memory.

   - bpo-23220(20): Explain how IDLE’s Shell displays output.

   - bpo-35099(21): Improve the doc about IDLE running user code.  The
     section is renamed from “IDLE – console differences” is renamed
     “Running user code”.  It mostly covers the implications of using
     custom ‘sys.stdXXX’ objects.

   - bpo-35097(22): Add IDLE doc subsection explaining editor windows.
     Topics include opening, title and status bar, .py* extension, and
     running.

   - bpo-35093(23): Document the IDLE document viewer in the IDLE doc.
     Add a paragraph in “Help and preferences”, “Help sources”
     subsection.

   - bpo-35088(24): Update idlelib.help.copy_string docstring.  We now
     use git and backporting instead of hg and forward merging.

   - bpo-35087(25): Update idlelib help files for the current doc build.
     The main change is the elimination of chapter-section numbers.

   - bpo-34548(26): Use configured color theme for read-only text views.

   - bpo-1529353(27): Enable “squeezing” of long outputs in the shell,
     to avoid performance degradation and to clean up the history
     without losing it.  Squeezed outputs may be copied, viewed in a
     separate window, and “unsqueezed”.

   - bpo-34047(28): Fixed mousewheel scrolling direction on macOS.

   - bpo-34275(29): Make IDLE calltips always visible on Mac.  Some
     MacOS-tk combinations need .update_idletasks().  Patch by Kevin
     Walzer.

   - bpo-34120(30): Fix unresponsiveness after closing certain windows
     and dialogs.

   - bpo-33975(31): Avoid small type when running htests.  Since part of
     the purpose of human-viewed tests is to determine that widgets look
     right, it is important that they look the same for testing as when
     running IDLE.

   - bpo-33905(32): Add test for idlelib.stackview.StackBrowser.

   - bpo-33924(33): Change mainmenu.menudefs key ‘windows’ to ‘window’.
     Every other menudef key is lowercase version of main menu entry.

   - bpo-33906(34): Rename idlelib.windows as window Match Window on the
     main menu and remove last plural module name.

   - bpo-33917(35): Fix and document idlelib/idle_test/template.py.  The
     revised file compiles, runs, and tests OK. idle_test/README.txt
     explains how to use it to create new IDLE test files.

   - bpo-33904(36): IDLE: In rstrip, rename class RstripExtension as
     Rstrip

   - bpo-33907(37): For consistency and clarity, rename an IDLE module
     and classes.  Module calltips and its class CallTips are now
     calltip and Calltip.  In module calltip_w, class CallTip is now
     CalltipWindow.

   - bpo-33856(38): Add “help” in the welcome message of IDLE

   - bpo-33839(39): IDLE: refactor ToolTip and CallTip and add
     documentation and tests

   - bpo-33855(40): Minimally test all IDLE modules.  Add missing files,
     import module, instantiate classes, and check coverage.  Check
     existing files.

   - bpo-33656(41): On Windows, add API call saying that tk scales for
     DPI. On Windows 8.1+ or 10, with DPI compatibility properties of
     the Python binary unchanged, and a monitor resolution greater than
     96 DPI, this should make text and lines sharper.  It should
     otherwise have no effect.

   - bpo-33768(42): Clicking on a context line moves that line to the
     top of the editor window.

   - bpo-33763(43): IDLE: Use read-only text widget for code context
     instead of label widget.

   - bpo-33664(44): Scroll IDLE editor text by lines.  Previously, the
     mouse wheel and scrollbar slider moved text by a fixed number of
     pixels, resulting in partial lines at the top of the editor box.
     The change also applies to the shell and grep output windows, but
     not to read-only text views.

   - bpo-33679(45): Enable theme-specific color configuration for Code
     Context.  Use the Highlights tab to see the setting for built-in
     themes or add settings to custom themes.

   - bpo-33642(46): Display up to maxlines non-blank lines for Code
     Context.  If there is no current context, show a single blank line.

   - bpo-33628(47): IDLE: Cleanup codecontext.py and its test.

   - bpo-33564(48): IDLE’s code context now recognizes async as a block
     opener.

   - bpo-21474(49): Update word/identifier definition from ascii to
     unicode.  In text and entry boxes, this affects selection by
     double-click, movement left/right by control-left/right, and
     deletion left/right by control-BACKSPACE/DEL.

   - bpo-33204(50): IDLE: consistently color invalid string prefixes.  A
     ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’.
     Consistently color as much of the prefix, starting at the right, as
     is valid.  Revise and extend colorizer test.

   - bpo-32984(51): Set ‘__file__’ while running a startup file.  Like
     Python, IDLE optionally runs one startup file in the Shell window
     before presenting the first interactive input prompt.  For IDLE,
     ‘-s’ runs a file named in environmental variable ‘IDLESTARTUP’ or
     *note PYTHONSTARTUP: 1003.; ‘-r file’ runs ‘file’.  Python sets
     ‘__file__’ to the startup file name before running the file and
     unsets it before the first prompt.  IDLE now does the same when run
     normally, without the ‘-n’ option.

   - bpo-32940(52): Simplify and rename StringTranslatePseudoMapping in
     pyparse.

   - bpo-32916(53): Change ‘str’ to ‘code’ in pyparse.

   - bpo-32905(54): Remove unused code in pyparse module.

   - bpo-32874(55): Add tests for pyparse.

   - bpo-32837(56): Using the system and place-dependent default
     encoding for open() is a bad idea for IDLE’s system and
     location-independent files.

   - bpo-32826(57): Add “encoding=utf-8” to open() in IDLE’s
     test_help_about.  GUI test test_file_buttons() only looks at
     initial ascii-only lines, but failed on systems where open()
     defaults to ‘ascii’ because readline() internally reads and decodes
     far enough ahead to encounter a non-ascii character in CREDITS.txt.

   - bpo-32831(58): Add docstrings and tests for codecontext.

   - bpo-32765(59): Update configdialog General tab docstring to add new
     widgets to the widget list.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35770

   (2) https://bugs.python.org/issue?@action=redirect&bpo=35769

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35660

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35641

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33987

   (6) https://bugs.python.org/issue?@action=redirect&bpo=34055

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35591

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35196

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35598

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28097

   (11) https://bugs.python.org/issue?@action=redirect&bpo=35208

   (12) https://bugs.python.org/issue?@action=redirect&bpo=35555

   (13) https://bugs.python.org/issue?@action=redirect&bpo=35521

   (14) https://bugs.python.org/issue?@action=redirect&bpo=22703

   (15) https://bugs.python.org/issue?@action=redirect&bpo=35213

   (16) https://bugs.python.org/issue?@action=redirect&bpo=34864

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34864

   (18) https://bugs.python.org/issue?@action=redirect&bpo=35202

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33000

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23220

   (21) https://bugs.python.org/issue?@action=redirect&bpo=35099

   (22) https://bugs.python.org/issue?@action=redirect&bpo=35097

   (23) https://bugs.python.org/issue?@action=redirect&bpo=35093

   (24) https://bugs.python.org/issue?@action=redirect&bpo=35088

   (25) https://bugs.python.org/issue?@action=redirect&bpo=35087

   (26) https://bugs.python.org/issue?@action=redirect&bpo=34548

   (27) https://bugs.python.org/issue?@action=redirect&bpo=1529353

   (28) https://bugs.python.org/issue?@action=redirect&bpo=34047

   (29) https://bugs.python.org/issue?@action=redirect&bpo=34275

   (30) https://bugs.python.org/issue?@action=redirect&bpo=34120

   (31) https://bugs.python.org/issue?@action=redirect&bpo=33975

   (32) https://bugs.python.org/issue?@action=redirect&bpo=33905

   (33) https://bugs.python.org/issue?@action=redirect&bpo=33924

   (34) https://bugs.python.org/issue?@action=redirect&bpo=33906

   (35) https://bugs.python.org/issue?@action=redirect&bpo=33917

   (36) https://bugs.python.org/issue?@action=redirect&bpo=33904

   (37) https://bugs.python.org/issue?@action=redirect&bpo=33907

   (38) https://bugs.python.org/issue?@action=redirect&bpo=33856

   (39) https://bugs.python.org/issue?@action=redirect&bpo=33839

   (40) https://bugs.python.org/issue?@action=redirect&bpo=33855

   (41) https://bugs.python.org/issue?@action=redirect&bpo=33656

   (42) https://bugs.python.org/issue?@action=redirect&bpo=33768

   (43) https://bugs.python.org/issue?@action=redirect&bpo=33763

   (44) https://bugs.python.org/issue?@action=redirect&bpo=33664

   (45) https://bugs.python.org/issue?@action=redirect&bpo=33679

   (46) https://bugs.python.org/issue?@action=redirect&bpo=33642

   (47) https://bugs.python.org/issue?@action=redirect&bpo=33628

   (48) https://bugs.python.org/issue?@action=redirect&bpo=33564

   (49) https://bugs.python.org/issue?@action=redirect&bpo=21474

   (50) https://bugs.python.org/issue?@action=redirect&bpo=33204

   (51) https://bugs.python.org/issue?@action=redirect&bpo=32984

   (52) https://bugs.python.org/issue?@action=redirect&bpo=32940

   (53) https://bugs.python.org/issue?@action=redirect&bpo=32916

   (54) https://bugs.python.org/issue?@action=redirect&bpo=32905

   (55) https://bugs.python.org/issue?@action=redirect&bpo=32874

   (56) https://bugs.python.org/issue?@action=redirect&bpo=32837

   (57) https://bugs.python.org/issue?@action=redirect&bpo=32826

   (58) https://bugs.python.org/issue?@action=redirect&bpo=32831

   (59) https://bugs.python.org/issue?@action=redirect&bpo=32765


File: python.info,  Node: Tools/Demos<30>,  Next: C API<55>,  Prev: IDLE<41>,  Up: Python 3 8 0 alpha 1

1.23.63.10 Tools/Demos
......................

   - bpo-35884(1): Add a benchmark script for timing various ways to
     access variables: ‘Tools/scripts/var_access_benchmark.py’.

   - bpo-34989(2): python-gdb.py now handles errors on computing the
     line number of a Python frame.

   - bpo-20260(3): Argument Clinic now has non-bitwise unsigned int
     converters.

   - bpo-32962(4): python-gdb now catches ‘UnicodeDecodeError’
     exceptions when calling ‘string()’.

   - bpo-32962(5): python-gdb now catches ValueError on read_var(): when
     Python has no debug symbols for example.

   - bpo-33189(6): ‘pygettext.py’ now recognizes only literal strings as
     docstrings and translatable strings, and rejects bytes literals and
     f-string expressions.

   - bpo-31920(7): Fixed handling directories as arguments in the
     ‘pygettext’ script.  Based on patch by Oleg Krasnikov.

   - bpo-29673(8): Fix pystackv and pystack gdbinit macros.

   - bpo-25427(9): Remove the pyvenv script in favor of ‘python3 -m
     venv’ in order to lower confusion as to what Python interpreter a
     virtual environment will be created for.

   - bpo-32885(10): Add an ‘-n’ flag for ‘Tools/scripts/pathfix.py’ to
     disable automatic backup creation (files with ‘~’ suffix).

   - bpo-32222(11): Fix pygettext not extracting docstrings for
     functions with type annotated arguments.  Patch by Toby Harradine.

   - bpo-31583(12): Fix 2to3 for using with –add-suffix option but
     without –output-dir option for relative path to files in current
     directory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35884

   (2) https://bugs.python.org/issue?@action=redirect&bpo=34989

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20260

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32962

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32962

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33189

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31920

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29673

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25427

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32885

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32222

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31583


File: python.info,  Node: C API<55>,  Prev: Tools/Demos<30>,  Up: Python 3 8 0 alpha 1

1.23.63.11 C API
................

   - bpo-35713(1): The ‘PyByteArray_Init()’ and ‘PyByteArray_Fini()’
     functions have been removed.  They did nothing since Python 2.7.4
     and Python 3.2.0, were excluded from the limited API (stable ABI),
     and were not documented.

   - bpo-33817(2): Fixed *note _PyBytes_Resize(): 1762. for empty bytes
     objects.

   - bpo-35322(3): Fix memory leak in *note PyUnicode_EncodeLocale():
     be9. and *note PyUnicode_EncodeFSDefault(): 1be2. on error
     handling.

   - bpo-35059(4): The following C macros have been converted to static
     inline functions: *note Py_INCREF(): 571, *note Py_DECREF(): 572,
     *note Py_XINCREF(): a73, *note Py_XDECREF(): 792, *note
     PyObject_INIT(): 1ae5, *note PyObject_INIT_VAR(): 1ae6.

   - bpo-35296(5): ‘make install’ now also installs the internal API:
     ‘Include/internal/*.h’ header files.

   - bpo-35081(6): Internal APIs surrounded by ‘#ifdef Py_BUILD_CORE’
     have been moved from ‘Include/*.h’ headers to new header files
     ‘Include/internal/pycore_*.h’.

   - bpo-35259(7): Conditionally declare *note Py_FinalizeEx(): d3d.
     (new in 3.6) based on Py_LIMITED_API. Patch by Arthur Neufeld.

   - bpo-35081(8): The ‘_PyObject_GC_TRACK()’ and
     ‘_PyObject_GC_UNTRACK()’ macros have been removed from the public C
     API.

   - bpo-35134(9): Creation of a new ‘Include/cpython/’ subdirectory.

   - bpo-34725(10): Adds _Py_SetProgramFullPath so embedders may
     override sys.executable

   - bpo-34910(11): Ensure that *note PyObject_Print(): 16fa. always
     returns ‘-1’ on error.  Patch by Zackery Spytz.

   - bpo-34523(12): Py_DecodeLocale() and Py_EncodeLocale() now use the
     UTF-8 encoding on Windows if Py_LegacyWindowsFSEncodingFlag is
     zero.

   - bpo-34193(13): Fix pluralization in TypeError messages in getargs.c
     and typeobject.c: ‘1 argument’ instead of ‘1 arguments’ and ‘1
     element’ instead of ‘1 elements’.

   - bpo-34127(14): Return grammatically correct error message based on
     argument count.  Patch by Karthikeyan Singaravelan.

   - bpo-23927(15): Fixed *note SystemError: 578. in *note
     PyArg_ParseTupleAndKeywords(): 386. when the ‘w*’ format unit is
     used for optional parameter.

   - bpo-32455(16): Added *note PyCompile_OpcodeStackEffectWithJump():
     1be3.

   - bpo-34008(17): Py_Main() can again be called after Py_Initialize(),
     as in Python 3.6.

   - bpo-32500(18): Fixed error messages for *note PySequence_Size():
     1be4, *note PySequence_GetItem(): 1be5, *note PySequence_SetItem():
     1be6. and *note PySequence_DelItem(): 1be7. called with a mapping
     and *note PyMapping_Size(): 1be8. called with a sequence.

   - bpo-33818(19): *note PyExceptionClass_Name(): a74. will now return
     ‘const char *’ instead of ‘char *’.

   - bpo-33042(20): Embedding applications may once again call
     PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption
     prior to calling Py_Initialize.

   - bpo-32374(21): Document that m_traverse for multi-phase initialized
     modules can be called with m_state=NULL, and add a sanity check

   - bpo-30863(22): *note PyUnicode_AsWideChar(): 1be9. and *note
     PyUnicode_AsWideCharString(): 8c4. no longer cache the ‘wchar_t*’
     representation of string objects.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=35713

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33817

   (3) https://bugs.python.org/issue?@action=redirect&bpo=35322

   (4) https://bugs.python.org/issue?@action=redirect&bpo=35059

   (5) https://bugs.python.org/issue?@action=redirect&bpo=35296

   (6) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (7) https://bugs.python.org/issue?@action=redirect&bpo=35259

   (8) https://bugs.python.org/issue?@action=redirect&bpo=35081

   (9) https://bugs.python.org/issue?@action=redirect&bpo=35134

   (10) https://bugs.python.org/issue?@action=redirect&bpo=34725

   (11) https://bugs.python.org/issue?@action=redirect&bpo=34910

   (12) https://bugs.python.org/issue?@action=redirect&bpo=34523

   (13) https://bugs.python.org/issue?@action=redirect&bpo=34193

   (14) https://bugs.python.org/issue?@action=redirect&bpo=34127

   (15) https://bugs.python.org/issue?@action=redirect&bpo=23927

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32455

   (17) https://bugs.python.org/issue?@action=redirect&bpo=34008

   (18) https://bugs.python.org/issue?@action=redirect&bpo=32500

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33818

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33042

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32374

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30863


File: python.info,  Node: Python 3 7 0 final,  Next: Python 3 7 0 release candidate 1,  Prev: Python 3 8 0 alpha 1,  Up: Changelog

1.23.64 Python 3.7.0 final
--------------------------

'Release date: 2018-06-27'

* Menu:

* Library: Library<139>.
* C API: C API<56>.


File: python.info,  Node: Library<139>,  Next: C API<56>,  Up: Python 3 7 0 final

1.23.64.1 Library
.................

   - bpo-33851(1): Fix *note ast.get_docstring(): 1bec. for a node that
     lacks a docstring.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33851


File: python.info,  Node: C API<56>,  Prev: Library<139>,  Up: Python 3 7 0 final

1.23.64.2 C API
...............

   - bpo-33932(1): Calling Py_Initialize() twice does nothing, instead
     of failing with a fatal error: restore the Python 3.6 behaviour.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33932


File: python.info,  Node: Python 3 7 0 release candidate 1,  Next: Python 3 7 0 beta 5,  Prev: Python 3 7 0 final,  Up: Changelog

1.23.65 Python 3.7.0 release candidate 1
----------------------------------------

'Release date: 2018-06-12'

* Menu:

* Core and Builtins: Core and Builtins<137>.
* Library: Library<140>.
* Documentation: Documentation<55>.
* Build: Build<61>.
* Windows: Windows<54>.
* IDLE: IDLE<42>.


File: python.info,  Node: Core and Builtins<137>,  Next: Library<140>,  Up: Python 3 7 0 release candidate 1

1.23.65.1 Core and Builtins
...........................

   - bpo-33803(1): Fix a crash in hamt.c caused by enabling GC tracking
     for an object that hadn’t all of its fields set to NULL.

   - bpo-33706(2): Fix a crash in Python initialization when parsing the
     command line options.  Thanks Christoph Gohlke for the bug report
     and the fix!

   - bpo-30654(3): Fixed reset of the SIGINT handler to SIG_DFL on
     interpreter shutdown even when there was a custom handler set
     previously.  Patch by Philipp Kerling.

   - bpo-31849(4): Fix signed/unsigned comparison warning in pyhash.c.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33803

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33706

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30654

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31849


File: python.info,  Node: Library<140>,  Next: Documentation<55>,  Prev: Core and Builtins<137>,  Up: Python 3 7 0 release candidate 1

1.23.65.2 Library
.................

   - bpo-30167(1): Prevent site.main() exception if PYTHONSTARTUP is
     set.  Patch by Steve Weber.

   - bpo-33812(2): Datetime instance d with non-None tzinfo, but with
     d.tzinfo.utcoffset(d) returning None is now treated as naive by the
     astimezone() method.

   - bpo-30805(3): Avoid race condition with debug logging

   - bpo-33694(4): asyncio: Fix a race condition causing data loss on
     pause_reading()/resume_reading() when using the ProactorEventLoop.

   - bpo-32493(5): Correct test for ‘uuid_enc_be’ availability in
     ‘configure.ac’.  Patch by Michael Felt.

   - bpo-33792(6): Add asyncio.WindowsSelectorEventLoopPolicy and
     asyncio.WindowsProactorEventLoopPolicy.

   - bpo-33778(7): Update ‘unicodedata’’s database to Unicode version
     11.0.0.

   - bpo-33770(8): improve base64 exception message for encoded inputs
     of invalid length

   - bpo-33769(9): asyncio/start_tls: Fix error message; cancel
     callbacks in case of an unhandled error; mark SSLTransport as
     closed if it is aborted.

   - bpo-33767(10): The concatenation (‘+’) and repetition (‘*’)
     sequence operations now raise *note TypeError: 2c3. instead of
     *note SystemError: 578. when performed on *note mmap.mmap: 20b.
     objects.  Patch by Zackery Spytz.

   - bpo-33734(11): asyncio/ssl: Fix AttributeError, increase default
     handshake timeout

   - bpo-11874(12): Use a better regex when breaking usage into
     wrappable parts.  Avoids bogus assertion errors from custom metavar
     strings.

   - bpo-33582(13): Emit a deprecation warning for inspect.formatargspec

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30167

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33812

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30805

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33694

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32493

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33792

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33778

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33770

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33769

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33767

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33734

   (12) https://bugs.python.org/issue?@action=redirect&bpo=11874

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33582


File: python.info,  Node: Documentation<55>,  Next: Build<61>,  Prev: Library<140>,  Up: Python 3 7 0 release candidate 1

1.23.65.3 Documentation
.......................

   - bpo-33409(1): Clarified the relationship between PEP 538(2)’s
     PYTHONCOERCECLOCALE and PEP 540’s PYTHONUTF8 mode.

   - bpo-33736(3): Improve the documentation of *note
     asyncio.open_connection(): b31, *note asyncio.start_server(): b32.
     and their UNIX socket counterparts.

   - bpo-31432(4): Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
     CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33409

   (2) https://peps.python.org/pep-0538/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33736

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31432


File: python.info,  Node: Build<61>,  Next: Windows<54>,  Prev: Documentation<55>,  Up: Python 3 7 0 release candidate 1

1.23.65.4 Build
...............

   - bpo-5755(1): Move ‘-Wstrict-prototypes’ option to ‘CFLAGS_NODIST’
     from ‘OPT’.  This option emitted annoying warnings when building
     extension modules written in C++.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5755


File: python.info,  Node: Windows<54>,  Next: IDLE<42>,  Prev: Build<61>,  Up: Python 3 7 0 release candidate 1

1.23.65.5 Windows
.................

   - bpo-33720(1): Reduces maximum marshal recursion depth on release
     builds.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33720


File: python.info,  Node: IDLE<42>,  Prev: Windows<54>,  Up: Python 3 7 0 release candidate 1

1.23.65.6 IDLE
..............

   - bpo-33656(1): On Windows, add API call saying that tk scales for
     DPI. On Windows 8.1+ or 10, with DPI compatibility properties of
     the Python binary unchanged, and a monitor resolution greater than
     96 DPI, this should make text and lines sharper.  It should
     otherwise have no effect.

   - bpo-33768(2): Clicking on a context line moves that line to the top
     of the editor window.

   - bpo-33763(3): IDLE: Use read-only text widget for code context
     instead of label widget.

   - bpo-33664(4): Scroll IDLE editor text by lines.  Previously, the
     mouse wheel and scrollbar slider moved text by a fixed number of
     pixels, resulting in partial lines at the top of the editor box.
     The change also applies to the shell and grep output windows, but
     not to read-only text views.

   - bpo-33679(5): Enable theme-specific color configuration for Code
     Context.  Use the Highlights tab to see the setting for built-in
     themes or add settings to custom themes.

   - bpo-33642(6): Display up to maxlines non-blank lines for Code
     Context.  If there is no current context, show a single blank line.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33656

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33768

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33763

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33664

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33679

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33642


File: python.info,  Node: Python 3 7 0 beta 5,  Next: Python 3 7 0 beta 4,  Prev: Python 3 7 0 release candidate 1,  Up: Changelog

1.23.66 Python 3.7.0 beta 5
---------------------------

'Release date: 2018-05-30'

* Menu:

* Core and Builtins: Core and Builtins<138>.
* Library: Library<141>.
* Documentation: Documentation<56>.
* Tests: Tests<57>.
* Build: Build<62>.
* macOS: macOS<43>.
* IDLE: IDLE<43>.


File: python.info,  Node: Core and Builtins<138>,  Next: Library<141>,  Up: Python 3 7 0 beta 5

1.23.66.1 Core and Builtins
...........................

   - bpo-33622(1): Fixed a leak when the garbage collector fails to add
     an object with the ‘__del__’ method or referenced by it into the
     *note gc.garbage: 1206. list.  *note PyGC_Collect(): 998. can now
     be called when an exception is set and preserves it.

   - bpo-33509(2): Fix module_globals parameter of
     warnings.warn_explicit(): don’t crash if module_globals is not a
     dict.

   - bpo-20104(3): The new ‘os.posix_spawn’ added in 3.7.0b1 was removed
     as we are still working on what the API should look like.  Expect
     this in 3.8 instead.

   - bpo-33475(4): Fixed miscellaneous bugs in converting annotations to
     strings and optimized parentheses in the string representation.

   - bpo-33391(5): Fix a leak in set_symmetric_difference().

   - bpo-28055(6): Fix unaligned accesses in siphash24().  Patch by Rolf
     Eike Beer.

   - bpo-32911(7): Due to unexpected compatibility issues discovered
     during downstream beta testing, reverted bpo-29463(8).  ‘docstring’
     field is removed from Module, ClassDef, FunctionDef, and
     AsyncFunctionDef ast nodes which was added in 3.7a1.  Docstring
     expression is restored as a first statement in their body.  Based
     on patch by Inada Naoki.

   - bpo-21983(9): Fix a crash in ‘ctypes.cast()’ in case the type
     argument is a ctypes structured data type.  Patch by Eryk Sun and
     Oren Milman.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33622

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33509

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20104

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33475

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33391

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28055

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32911

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29463

   (9) https://bugs.python.org/issue?@action=redirect&bpo=21983


File: python.info,  Node: Library<141>,  Next: Documentation<56>,  Prev: Core and Builtins<138>,  Up: Python 3 7 0 beta 5

1.23.66.2 Library
.................

   - bpo-32751(1): When cancelling the task due to a timeout, *note
     asyncio.wait_for(): 602. will now wait until the cancellation is
     complete.

   - bpo-32684(2): Fix gather to propagate cancellation of itself even
     with return_exceptions.

   - bpo-33654(3): Support protocol type switching in
     SSLTransport.set_protocol().

   - bpo-33674(4): Pause the transport as early as possible to further
     reduce the risk of data_received() being called before
     connection_made().

   - bpo-33674(5): Fix a race condition in SSLProtocol.connection_made()
     of asyncio.sslproto: start immediately the handshake instead of
     using call_soon().  Previously, data_received() could be called
     before the handshake started, causing the handshake to hang or
     fail.

   - bpo-31647(6): Fixed bug where calling write_eof() on a
     _SelectorSocketTransport after it’s already closed raises
     AttributeError.

   - bpo-32610(7): Make asyncio.all_tasks() return only pending tasks.

   - bpo-32410(8): Avoid blocking on file IO in sendfile fallback code

   - bpo-33469(9): Fix RuntimeError after closing loop that used
     run_in_executor

   - bpo-33672(10): Fix Task.__repr__ crash with Cython’s bogus
     coroutines

   - bpo-33654(11): Fix transport.set_protocol() to support switching
     between asyncio.Protocol and asyncio.BufferedProtocol.  Fix
     loop.start_tls() to work with asyncio.BufferedProtocols.

   - bpo-33652(12): Pickles of type variables and subscripted generics
     are now future-proof and compatible with older Python versions.

   - bpo-32493(13): Fixed *note uuid.uuid1(): bc6. on FreeBSD.

   - bpo-33618(14): Finalize and document preliminary and experimental
     TLS 1.3 support with OpenSSL 1.1.1

   - bpo-33623(15): Fix possible SIGSGV when asyncio.Future is created
     in __del__

   - bpo-30877(16): Fixed a bug in the Python implementation of the JSON
     decoder that prevented the cache of parsed strings from clearing
     after finishing the decoding.  Based on patch by c-fos.

   - bpo-33570(17): Change TLS 1.3 cipher suite settings for
     compatibility with OpenSSL 1.1.1-pre6 and newer.  OpenSSL 1.1.1
     will have TLS 1.3 ciphers enabled by default.

   - bpo-28556(18): Do not simplify arguments to ‘typing.Union’.  Now
     ‘Union[Manager, Employee]’ is not simplified to ‘Employee’ at
     runtime.  Such simplification previously caused several bugs and
     limited possibilities for introspection.

   - bpo-33540(19): Add a new ‘block_on_close’ class attribute to
     ‘ForkingMixIn’ and ‘ThreadingMixIn’ classes of *note socketserver:
     cd.

   - bpo-33548(20): tempfile._candidate_tempdir_list should consider
     common TEMP locations

   - bpo-33109(21): argparse subparsers are once again not required by
     default, reverting the change in behavior introduced by
     bpo-26510(22) in 3.7.0a2.

   - bpo-33536(23): dataclasses.make_dataclass now checks for invalid
     field names and duplicate fields.  Also, added a check for invalid
     field specifications.

   - bpo-33542(24): Prevent ‘uuid.get_node’ from using a DUID instead of
     a MAC on Windows.  Patch by Zvi Effron

   - bpo-26819(25): Fix race condition with
     ‘ReadTransport.resume_reading’ in Windows proactor event loop.

   - Fix failure in ‘typing.get_type_hints()’ when ClassVar was provided
     as a string forward reference.

   - bpo-33505(26): Optimize asyncio.ensure_future() by reordering if
     checks: 1.17x faster.

   - bpo-33497(27): Add errors param to cgi.parse_multipart and make an
     encoding in FieldStorage use the given errors (needed for Twisted).
     Patch by Amber Brown.

   - bpo-33495(28): Change dataclasses.Fields repr to use the repr of
     each of its members, instead of str.  This makes it more clear what
     each field actually represents.  This is especially true for the
     ‘type’ member.

   - bpo-33453(29): Fix dataclasses to work if using literal string type
     annotations or if using PEP 563 “Postponed Evaluation of
     Annotations”.  Only specific string prefixes are detected for both
     ClassVar (“ClassVar” and “typing.ClassVar”) and InitVar (“InitVar”
     and “dataclasses.InitVar”).

   - bpo-28556(30): Minor fixes in typing module: add annotations to
     ‘NamedTuple.__new__’, pass ‘*args’ and ‘**kwds’ in
     ‘Generic.__new__’.  Original PRs by Paulius Šarka and Chad
     Dombrova.

   - bpo-20087(31): Updated alias mapping with glibc 2.27 supported
     locales.

   - bpo-33422(32): Fix trailing quotation marks getting deleted when
     looking up byte/string literals on pydoc.  Patch by Andrés Delfino.

   - bpo-28167(33): The function ‘platform.linux_distribution’ and
     ‘platform.dist’ now trigger a ‘DeprecationWarning’ and have been
     marked for removal in Python 3.8

   - bpo-33197(34): Update error message when constructing invalid
     inspect.Parameters Patch by Donghee Na.

   - bpo-33263(35): Fix FD leak in ‘_SelectorSocketTransport’ Patch by
     Vlad Starostin.

   - bpo-32861(36): The urllib.robotparser’s ‘__str__’ representation
     now includes wildcard entries and the “Crawl-delay” and
     “Request-rate” fields.  Patch by Michael Lazar.

   - bpo-32257(37): The ssl module now contains OP_NO_RENEGOTIATION
     constant, available with OpenSSL 1.1.0h or 1.1.1.

   - bpo-16865(38): Support arrays >=2GiB in *note ctypes: 2a.  Patch by
     Segev Finer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32751

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32684

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33654

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33674

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33674

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31647

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32610

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32410

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33469

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33672

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33654

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33652

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32493

   (14) https://bugs.python.org/issue?@action=redirect&bpo=33618

   (15) https://bugs.python.org/issue?@action=redirect&bpo=33623

   (16) https://bugs.python.org/issue?@action=redirect&bpo=30877

   (17) https://bugs.python.org/issue?@action=redirect&bpo=33570

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33540

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33548

   (21) https://bugs.python.org/issue?@action=redirect&bpo=33109

   (22) https://bugs.python.org/issue?@action=redirect&bpo=26510

   (23) https://bugs.python.org/issue?@action=redirect&bpo=33536

   (24) https://bugs.python.org/issue?@action=redirect&bpo=33542

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26819

   (26) https://bugs.python.org/issue?@action=redirect&bpo=33505

   (27) https://bugs.python.org/issue?@action=redirect&bpo=33497

   (28) https://bugs.python.org/issue?@action=redirect&bpo=33495

   (29) https://bugs.python.org/issue?@action=redirect&bpo=33453

   (30) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (31) https://bugs.python.org/issue?@action=redirect&bpo=20087

   (32) https://bugs.python.org/issue?@action=redirect&bpo=33422

   (33) https://bugs.python.org/issue?@action=redirect&bpo=28167

   (34) https://bugs.python.org/issue?@action=redirect&bpo=33197

   (35) https://bugs.python.org/issue?@action=redirect&bpo=33263

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32861

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32257

   (38) https://bugs.python.org/issue?@action=redirect&bpo=16865


File: python.info,  Node: Documentation<56>,  Next: Tests<57>,  Prev: Library<141>,  Up: Python 3 7 0 beta 5

1.23.66.3 Documentation
.......................

   - bpo-23859(1): Document that ‘asyncio.wait()’ does not cancel its
     futures on timeout.

   - bpo-32436(2): Document PEP 567(3) changes to asyncio.

   - bpo-33604(4): Update HMAC md5 default to a DeprecationWarning, bump
     removal to 3.8.

   - bpo-33503(5): Fix broken pypi link

   - bpo-33421(6): Add missing documentation for
     ‘typing.AsyncContextManager’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23859

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (3) https://peps.python.org/pep-0567/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33604

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33503

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33421


File: python.info,  Node: Tests<57>,  Next: Build<62>,  Prev: Documentation<56>,  Up: Python 3 7 0 beta 5

1.23.66.4 Tests
...............

   - bpo-33655(1): Ignore test_posix_fallocate failures on BSD platforms
     that might be due to running on ZFS.

   - bpo-32604(2): Remove the _xxsubinterpreters module (meant for
     testing) and associated helpers.  This module was originally added
     recently in 3.7b1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33655

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32604


File: python.info,  Node: Build<62>,  Next: macOS<43>,  Prev: Tests<57>,  Up: Python 3 7 0 beta 5

1.23.66.5 Build
...............

   - bpo-33614(1): Ensures module definition files for the stable ABI on
     Windows are correctly regenerated.

   - bpo-33522(2): Enable CI builds on Visual Studio Team Services at
     ‘https://python.visualstudio.com/cpython’

   - bpo-33012(3): Add ‘-Wno-cast-function-type’ for gcc 8 for silencing
     warnings about function casts like casting to PyCFunction in method
     definition lists.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33614

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33522

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33012


File: python.info,  Node: macOS<43>,  Next: IDLE<43>,  Prev: Build<62>,  Up: Python 3 7 0 beta 5

1.23.66.6 macOS
...............

   - bpo-13631(1): The .editrc file in user’s home directory is now
     processed correctly during the readline initialization through
     editline emulation on macOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13631


File: python.info,  Node: IDLE<43>,  Prev: macOS<43>,  Up: Python 3 7 0 beta 5

1.23.66.7 IDLE
..............

   - bpo-33628(1): IDLE: Cleanup codecontext.py and its test.

   - bpo-33564(2): IDLE’s code context now recognizes async as a block
     opener.

   - bpo-32831(3): Add docstrings and tests for codecontext.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33628

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33564

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32831


File: python.info,  Node: Python 3 7 0 beta 4,  Next: Python 3 7 0 beta 3,  Prev: Python 3 7 0 beta 5,  Up: Changelog

1.23.67 Python 3.7.0 beta 4
---------------------------

'Release date: 2018-05-02'

* Menu:

* Core and Builtins: Core and Builtins<139>.
* Library: Library<142>.
* Documentation: Documentation<57>.
* Tests: Tests<58>.
* Build: Build<63>.
* Windows: Windows<55>.
* macOS: macOS<44>.
* IDLE: IDLE<44>.
* Tools/Demos: Tools/Demos<31>.


File: python.info,  Node: Core and Builtins<139>,  Next: Library<142>,  Up: Python 3 7 0 beta 4

1.23.67.1 Core and Builtins
...........................

   - bpo-33363(1): Raise a SyntaxError for ‘async with’ and ‘async for’
     statements outside of async functions.

   - bpo-33128(2): Fix a bug that causes PathFinder to appear twice on
     sys.meta_path.  Patch by Pablo Galindo Salgado.

   - bpo-33312(3): Fixed clang ubsan (undefined behavior sanitizer)
     warnings in dictobject.c by adjusting how the internal struct
     _dictkeysobject shared keys structure is declared.

   - bpo-33231(4): Fix potential memory leak in ‘normalizestring()’.

   - bpo-33205(5): Change dict growth function from
     ‘round_up_to_power_2(used*2+hashtable_size/2)’ to
     ‘round_up_to_power_2(used*3)’.  Previously, dict is shrinked only
     when ‘used == 0’.  Now dict has more chance to be shrinked.

   - bpo-29922(6): Improved error messages in ‘async with’ when
     ‘__aenter__()’ or ‘__aexit__()’ return non-awaitable object.

   - bpo-33199(7): Fix ‘ma_version_tag’ in dict implementation is
     uninitialized when copying from key-sharing dict.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33363

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33128

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33312

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33231

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33205

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29922

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33199


File: python.info,  Node: Library<142>,  Next: Documentation<57>,  Prev: Core and Builtins<139>,  Up: Python 3 7 0 beta 4

1.23.67.2 Library
.................

   - bpo-33281(1): Fix ctypes.util.find_library regression on macOS.

   - bpo-33383(2): Fixed crash in the get() method of the *note
     dbm.ndbm: 34. database object when it is called with a single
     argument.

   - bpo-33329(3): Fix multiprocessing regression on newer glibcs

   - bpo-991266(4): Fix quoting of the ‘Comment’ attribute of *note
     http.cookies.SimpleCookie: 1bd3.

   - bpo-33131(5): Upgrade bundled version of pip to 10.0.1.

   - bpo-33308(6): Fixed a crash in the ‘parser’ module when converting
     an ST object to a tree of tuples or lists with ‘line_info=False’
     and ‘col_info=True’.

   - bpo-33266(7): lib2to3 now recognizes ‘rf'...'’ strings.

   - bpo-11594(8): Ensure line-endings are respected when using lib2to3.

   - bpo-33254(9): Have *note importlib.resources.contents(): 1f2. and
     *note importlib.abc.ResourceReader.contents(): 1bd4. return an
     *note iterable: 126d. instead of an *note iterator: 1ac.

   - bpo-33256(10): Fix display of ‘<module>’ call in the html produced
     by ‘cgitb.html()’.  Patch by Stéphane Blondon.

   - bpo-33185(11): Fixed regression when running pydoc with the *note
     -m: 5e4. switch.  (The regression was introduced in 3.7.0b3 by the
     resolution of bpo-33053(12)) This fix also changed pydoc to add
     ‘os.getcwd()’ to *note sys.path: 3b7. when necessary, rather than
     adding ‘"."’.

   - bpo-33169(13): Delete entries of ‘None’ in *note
     sys.path_importer_cache: 5e7. when
     ‘importlib.machinery.invalidate_caches()’ is called.

   - bpo-33217(14): Deprecate looking up non-Enum objects in Enum
     classes and Enum members (will raise *note TypeError: 2c3. in
     3.8+).

   - bpo-33203(15): ‘random.Random.choice()’ now raises ‘IndexError’ for
     empty sequences consistently even when called from subclasses
     without a ‘getrandbits()’ implementation.

   - bpo-33224(16): Update difflib.mdiff() for PEP 479(17).  Convert an
     uncaught StopIteration in a generator into a return-statement.

   - bpo-33209(18): End framing at the end of C implementation of *note
     pickle.Pickler.dump(): 1bd5.

   - bpo-20104(19): Improved error handling and fixed a reference leak
     in *note os.posix_spawn(): 220.

   - bpo-33175(20): In dataclasses, Field.__set_name__ now looks up the
     __set_name__ special method on the class, not the instance, of the
     default value.

   - bpo-33097(21): Raise RuntimeError when ‘executor.submit’ is called
     during interpreter shutdown.

   - bpo-31908(22): Fix output of cover files for ‘trace’ module
     command-line tool.  Previously emitted cover files only when
     ‘--missing’ option was used.  Patch by Michael Selik.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33281

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33383

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33329

   (4) https://bugs.python.org/issue?@action=redirect&bpo=991266

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33131

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33308

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33266

   (8) https://bugs.python.org/issue?@action=redirect&bpo=11594

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33254

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33256

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33185

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33053

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33169

   (14) https://bugs.python.org/issue?@action=redirect&bpo=33217

   (15) https://bugs.python.org/issue?@action=redirect&bpo=33203

   (16) https://bugs.python.org/issue?@action=redirect&bpo=33224

   (17) https://peps.python.org/pep-0479/

   (18) https://bugs.python.org/issue?@action=redirect&bpo=33209

   (19) https://bugs.python.org/issue?@action=redirect&bpo=20104

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33175

   (21) https://bugs.python.org/issue?@action=redirect&bpo=33097

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31908


File: python.info,  Node: Documentation<57>,  Next: Tests<58>,  Prev: Library<142>,  Up: Python 3 7 0 beta 4

1.23.67.3 Documentation
.......................

   - bpo-33378(1): Add Korean language switcher for
     ‘https://docs.python.org/3/’

   - bpo-33276(2): Clarify that the ‘__path__’ attribute on modules
     cannot be just any value.

   - bpo-33201(3): Modernize documentation for writing C extension
     types.

   - bpo-33195(4): Deprecate ‘Py_UNICODE’ usage in ‘c-api/arg’ document.
     ‘Py_UNICODE’ related APIs are deprecated since Python 3.3, but it
     is missed in the document.

   - bpo-8243(5): Add a note about curses.addch and curses.addstr
     exception behavior when writing outside a window, or pad.

   - bpo-32337(6): Update documentation related with ‘dict’ order.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33378

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33276

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33201

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33195

   (5) https://bugs.python.org/issue?@action=redirect&bpo=8243

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32337


File: python.info,  Node: Tests<58>,  Next: Build<63>,  Prev: Documentation<57>,  Up: Python 3 7 0 beta 4

1.23.67.4 Tests
...............

   - bpo-33358(1): Fix
     ‘test_embed.test_pre_initialization_sys_options()’ when the
     interpreter is built with ‘--enable-shared’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33358


File: python.info,  Node: Build<63>,  Next: Windows<55>,  Prev: Tests<58>,  Up: Python 3 7 0 beta 4

1.23.67.5 Build
...............

   - bpo-33394(1): Enable the verbose build for extension modules, when
     GNU make is passed macros on the command line.

   - bpo-33393(2): Update config.guess and config.sub files.

   - bpo-33377(3): Add new triplets for mips r6 and riscv variants (used
     in extension suffixes).

   - bpo-32232(4): By default, modules configured in ‘Modules/Setup’ are
     no longer built with ‘-DPy_BUILD_CORE’.  Instead, modules that
     specifically need that preprocessor definition include it in their
     individual entries.

   - bpo-33182(5): The embedding tests can once again be built with
     clang 6.0

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33394

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33393

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33377

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32232

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33182


File: python.info,  Node: Windows<55>,  Next: macOS<44>,  Prev: Build<63>,  Up: Python 3 7 0 beta 4

1.23.67.6 Windows
.................

   - bpo-33184(1): Update Windows installer to use OpenSSL 1.1.0h.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33184


File: python.info,  Node: macOS<44>,  Next: IDLE<44>,  Prev: Windows<55>,  Up: Python 3 7 0 beta 4

1.23.67.7 macOS
...............

   - bpo-33184(1): Update macOS installer build to use OpenSSL 1.1.0h.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33184


File: python.info,  Node: IDLE<44>,  Next: Tools/Demos<31>,  Prev: macOS<44>,  Up: Python 3 7 0 beta 4

1.23.67.8 IDLE
..............

   - bpo-21474(1): Update word/identifier definition from ascii to
     unicode.  In text and entry boxes, this affects selection by
     double-click, movement left/right by control-left/right, and
     deletion left/right by control-BACKSPACE/DEL.

   - bpo-33204(2): IDLE: consistently color invalid string prefixes.  A
     ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’.
     Consistently color as much of the prefix, starting at the right, as
     is valid.  Revise and extend colorizer test.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21474

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33204


File: python.info,  Node: Tools/Demos<31>,  Prev: IDLE<44>,  Up: Python 3 7 0 beta 4

1.23.67.9 Tools/Demos
.....................

   - bpo-33189(1): ‘pygettext.py’ now recognizes only literal strings as
     docstrings and translatable strings, and rejects bytes literals and
     f-string expressions.

   - bpo-31920(2): Fixed handling directories as arguments in the
     ‘pygettext’ script.  Based on patch by Oleg Krasnikov.

   - bpo-29673(3): Fix pystackv and pystack gdbinit macros.

   - bpo-31583(4): Fix 2to3 for using with –add-suffix option but
     without –output-dir option for relative path to files in current
     directory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33189

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31920

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29673

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31583


File: python.info,  Node: Python 3 7 0 beta 3,  Next: Python 3 7 0 beta 2,  Prev: Python 3 7 0 beta 4,  Up: Changelog

1.23.68 Python 3.7.0 beta 3
---------------------------

'Release date: 2018-03-29'

* Menu:

* Security: Security<44>.
* Core and Builtins: Core and Builtins<140>.
* Library: Library<143>.
* Documentation: Documentation<58>.
* Tests: Tests<59>.
* Build: Build<64>.
* Windows: Windows<56>.
* macOS: macOS<45>.
* IDLE: IDLE<45>.
* Tools/Demos: Tools/Demos<32>.
* C API: C API<57>.


File: python.info,  Node: Security<44>,  Next: Core and Builtins<140>,  Up: Python 3 7 0 beta 3

1.23.68.1 Security
..................

   - bpo-33136(1): Harden ssl module against LibreSSL CVE 2018-8970(2).
     X509_VERIFY_PARAM_set1_host() is called with an explicit namelen.
     A new test ensures that NULL bytes are not allowed.

   - bpo-33001(3): Minimal fix to prevent buffer overrun in os.symlink
     on Windows

   - bpo-32981(4): Regexes in difflib and poplib were vulnerable to
     catastrophic backtracking.  These regexes formed potential DOS
     vectors (REDOS). They have been refactored.  This resolves CVE
     2018-1060(5) and CVE 2018-1061(6).  Patch by Jamie Davis.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33136

   (2) https://www.cve.org/CVERecord?id=CVE-2018-8970

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33001

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32981

   (5) https://www.cve.org/CVERecord?id=CVE-2018-1060

   (6) https://www.cve.org/CVERecord?id=CVE-2018-1061


File: python.info,  Node: Core and Builtins<140>,  Next: Library<143>,  Prev: Security<44>,  Up: Python 3 7 0 beta 3

1.23.68.2 Core and Builtins
...........................

   - bpo-33053(1): When using the -m switch, sys.path[0] is now
     explicitly expanded as the 'starting' working directory, rather
     than being left as the empty path (which allows imports from the
     current working directory at the time of the import)

   - bpo-33018(2): Improve consistency of errors raised by
     ‘issubclass()’ when called with a non-class and an abstract base
     class as the first and second arguments, respectively.  Patch by
     Josh Bronson.

   - bpo-33041(3): Fixed jumping when the function contains an ‘async
     for’ loop.

   - bpo-33026(4): Fixed jumping out of “with” block by setting
     f_lineno.

   - bpo-33005(5): Fix a crash on fork when using a custom memory
     allocator (ex: using PYTHONMALLOC env var).  _PyGILState_Reinit()
     and _PyInterpreterState_Enable() now use the default RAW memory
     allocator to allocate a new interpreters mutex on fork.

   - bpo-17288(6): Prevent jumps from ‘return’ and ‘exception’ trace
     events.

   - bpo-32836(7): Don’t use temporary variables in cases of
     list/dict/set comprehensions

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33053

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33018

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33041

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33026

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33005

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17288

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32836


File: python.info,  Node: Library<143>,  Next: Documentation<58>,  Prev: Core and Builtins<140>,  Up: Python 3 7 0 beta 3

1.23.68.3 Library
.................

   - bpo-33141(1): Have Field objects pass through __set_name__ to their
     default values, if they have their own __set_name__.

   - bpo-33096(2): Allow ttk.Treeview.insert to insert iid that has a
     false boolean value.  Note iid=0 and iid=False would be same.
     Patch by Garvit Khatri.

   - bpo-32873(3): Treat type variables and special typing forms as
     immutable by copy and pickle.  This fixes several minor issues and
     inconsistencies, and improves backwards compatibility with Python
     3.6.

   - bpo-33134(4): When computing dataclass’s __hash__, use the lookup
     table to contain the function which returns the __hash__ value.
     This is an improvement over looking up a string, and then testing
     that string to see what to do.

   - bpo-33127(5): The ssl module now compiles with LibreSSL 2.7.1.

   - bpo-32505(6): Raise TypeError if a member variable of a dataclass
     is of type Field, but doesn’t have a type annotation.

   - bpo-33078(7): Fix the failure on OSX caused by the tests relying on
     sem_getvalue

   - bpo-33116(8): Add ‘Field’ to dataclasses.__all__.

   - bpo-32896(9): Fix an error where subclassing a dataclass with a
     field that uses a default_factory would generate an incorrect
     class.

   - bpo-33100(10): Dataclasses: If a field has a default value that’s a
     MemberDescriptorType, then it’s from that field being in __slots__,
     not an actual default value.

   - bpo-32953(11): If a non-dataclass inherits from a frozen dataclass,
     allow attributes to be added to the derived class.  Only attributes
     from the frozen dataclass cannot be assigned to.  Require all
     dataclasses in a hierarchy to be either all frozen or all
     non-frozen.

   - bpo-33061(12): Add missing ‘NoReturn’ to ‘__all__’ in typing.py

   - bpo-33078(13): Fix the size handling in multiprocessing.Queue when
     a pickling error occurs.

   - bpo-33064(14): lib2to3 now properly supports trailing commas after
     ‘*args’ and ‘**kwargs’ in function signatures.

   - bpo-33056(15): FIX properly close leaking fds in
     concurrent.futures.ProcessPoolExecutor.

   - bpo-33021(16): Release the GIL during fstat() calls, avoiding hang
     of all threads when calling mmap.mmap(), os.urandom(), and
     random.seed().  Patch by Nir Soffer.

   - bpo-31804(17): Avoid failing in multiprocessing.Process if the
     standard streams are closed or None at exit.

   - bpo-33037(18): Skip sending/receiving data after SSL transport
     closing.

   - bpo-27683(19): Fix a regression in *note ipaddress: 80. that result
     of ‘hosts()’ is empty when the network is constructed by a tuple
     containing an integer mask and only 1 bit left for addresses.

   - bpo-32999(20): Fix C implementation of ‘ABC.__subclasscheck__(cls,
     subclass)’ crashed when ‘subclass’ is not a type object.

   - bpo-33009(21): Fix inspect.signature() for single-parameter
     partialmethods.

   - bpo-32969(22): Expose several missing constants in zlib and fix
     corresponding documentation.

   - bpo-32056(23): Improved exceptions raised for invalid number of
     channels and sample width when read an audio file in modules
     ‘aifc’, *note wave: 113. and ‘sunau’.

   - bpo-32844(24): Fix wrong redirection of a low descriptor (0 or 1)
     to stderr in subprocess if another low descriptor is closed.

   - bpo-32857(25): In *note tkinter: f0, ‘after_cancel(None)’ now
     raises a *note ValueError: 202. instead of canceling the first
     scheduled function.  Patch by Cheryl Sabella.

   - bpo-31639(26): http.server now exposes a ThreadedHTTPServer class
     and uses it when the module is run with ‘-m’ to cope with web
     browsers pre-opening sockets.

   - bpo-27645(27): *note sqlite3.Connection: 245. now exposes a *note
     backup: b98. method, if the underlying SQLite library is at version
     3.6.11 or higher.  Patch by Lele Gaifax.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33141

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33096

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32873

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33134

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33127

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32505

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33078

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33116

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32896

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33100

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32953

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33061

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33078

   (14) https://bugs.python.org/issue?@action=redirect&bpo=33064

   (15) https://bugs.python.org/issue?@action=redirect&bpo=33056

   (16) https://bugs.python.org/issue?@action=redirect&bpo=33021

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31804

   (18) https://bugs.python.org/issue?@action=redirect&bpo=33037

   (19) https://bugs.python.org/issue?@action=redirect&bpo=27683

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32999

   (21) https://bugs.python.org/issue?@action=redirect&bpo=33009

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32969

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32056

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32844

   (25) https://bugs.python.org/issue?@action=redirect&bpo=32857

   (26) https://bugs.python.org/issue?@action=redirect&bpo=31639

   (27) https://bugs.python.org/issue?@action=redirect&bpo=27645


File: python.info,  Node: Documentation<58>,  Next: Tests<59>,  Prev: Library<143>,  Up: Python 3 7 0 beta 3

1.23.68.4 Documentation
.......................

   - bpo-33126(1): Document PyBuffer_ToContiguous().

   - bpo-27212(2): Modify documentation for the ‘islice()’ recipe to
     consume initial values up to the start index.

   - bpo-28247(3): Update *note zipapp: 130. documentation to describe
     how to make standalone applications.

   - bpo-18802(4): Documentation changes for ipaddress.  Patch by Jon
     Foster and Berker Peksag.

   - bpo-27428(5): Update documentation to clarify that
     ‘WindowsRegistryFinder’ implements ‘MetaPathFinder’.  (Patch by
     Himanshu Lakhara)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33126

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27212

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28247

   (4) https://bugs.python.org/issue?@action=redirect&bpo=18802

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27428


File: python.info,  Node: Tests<59>,  Next: Build<64>,  Prev: Documentation<58>,  Up: Python 3 7 0 beta 3

1.23.68.5 Tests
...............

   - bpo-32872(1): Avoid regrtest compatibility issue with namespace
     packages.

   - bpo-32517(2): Fix failing ‘test_asyncio’ on macOS 10.12.2+ due to
     transport of ‘KqueueSelector’ loop was not being closed.

   - bpo-19417(3): Add test_bdb.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32872

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32517

   (3) https://bugs.python.org/issue?@action=redirect&bpo=19417


File: python.info,  Node: Build<64>,  Next: Windows<56>,  Prev: Tests<59>,  Up: Python 3 7 0 beta 3

1.23.68.6 Build
...............

   - bpo-33163(1): Upgrade pip to 9.0.3 and setuptools to v39.0.1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33163


File: python.info,  Node: Windows<56>,  Next: macOS<45>,  Prev: Build<64>,  Up: Python 3 7 0 beta 3

1.23.68.7 Windows
.................

   - bpo-33016(1): Fix potential use of uninitialized memory in
     nt._getfinalpathname

   - bpo-32903(2): Fix a memory leak in os.chdir() on Windows if the
     current directory is set to a UNC path.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33016

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32903


File: python.info,  Node: macOS<45>,  Next: IDLE<45>,  Prev: Windows<56>,  Up: Python 3 7 0 beta 3

1.23.68.8 macOS
...............

   - bpo-32726(1): Build and link with private copy of Tcl/Tk 8.6 for
     the macOS 10.6+ installer.  The 10.9+ installer variant already
     does this.  This means that the Python 3.7 provided by the
     python.org macOS installers no longer need or use any external
     versions of Tcl/Tk, either system-provided or user-installed, such
     as ActiveTcl.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32726


File: python.info,  Node: IDLE<45>,  Next: Tools/Demos<32>,  Prev: macOS<45>,  Up: Python 3 7 0 beta 3

1.23.68.9 IDLE
..............

   - bpo-32984(1): Set ‘__file__’ while running a startup file.  Like
     Python, IDLE optionally runs one startup file in the Shell window
     before presenting the first interactive input prompt.  For IDLE,
     ‘-s’ runs a file named in environmental variable ‘IDLESTARTUP’ or
     *note PYTHONSTARTUP: 1003.; ‘-r file’ runs ‘file’.  Python sets
     ‘__file__’ to the startup file name before running the file and
     unsets it before the first prompt.  IDLE now does the same when run
     normally, without the ‘-n’ option.

   - bpo-32940(2): Simplify and rename StringTranslatePseudoMapping in
     pyparse.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32984

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32940


File: python.info,  Node: Tools/Demos<32>,  Next: C API<57>,  Prev: IDLE<45>,  Up: Python 3 7 0 beta 3

1.23.68.10 Tools/Demos
......................

   - bpo-32885(1): Add an ‘-n’ flag for ‘Tools/scripts/pathfix.py’ to
     disable automatic backup creation (files with ‘~’ suffix).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32885


File: python.info,  Node: C API<57>,  Prev: Tools/Demos<32>,  Up: Python 3 7 0 beta 3

1.23.68.11 C API
................

   - bpo-33042(1): Embedding applications may once again call
     PySys_ResetWarnOptions, PySys_AddWarnOption, and PySys_AddXOption
     prior to calling Py_Initialize.

   - bpo-32374(2): Document that m_traverse for multi-phase initialized
     modules can be called with m_state=NULL, and add a sanity check

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33042

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32374


File: python.info,  Node: Python 3 7 0 beta 2,  Next: Python 3 7 0 beta 1,  Prev: Python 3 7 0 beta 3,  Up: Changelog

1.23.69 Python 3.7.0 beta 2
---------------------------

'Release date: 2018-02-27'

* Menu:

* Security: Security<45>.
* Core and Builtins: Core and Builtins<141>.
* Library: Library<144>.
* Documentation: Documentation<59>.
* Tests: Tests<60>.
* Build: Build<65>.
* Windows: Windows<57>.
* macOS: macOS<46>.
* IDLE: IDLE<46>.
* Tools/Demos: Tools/Demos<33>.


File: python.info,  Node: Security<45>,  Next: Core and Builtins<141>,  Up: Python 3 7 0 beta 2

1.23.69.1 Security
..................

   - bpo-28414(1): The ssl module now allows users to perform their own
     IDN en/decoding when using SNI.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28414


File: python.info,  Node: Core and Builtins<141>,  Next: Library<144>,  Prev: Security<45>,  Up: Python 3 7 0 beta 2

1.23.69.2 Core and Builtins
...........................

   - bpo-32889(1): Update Valgrind suppression list to account for the
     rename of ‘Py_ADDRESS_IN_RANG’ to ‘address_in_range’.

   - bpo-31356(2): Remove the new API added in bpo-31356(3)
     (gc.ensure_disabled() context manager).

   - bpo-32305(4): For namespace packages, ensure that both ‘__file__’
     and ‘__spec__.origin’ are set to None.

   - bpo-32303(5): Make sure ‘__spec__.loader’ matches ‘__loader__’ for
     namespace packages.

   - bpo-32711(6): Fix the warning messages for Python/ast_unparse.c.
     Patch by Stéphane Wirtel

   - bpo-32583(7): Fix possible crashing in builtin Unicode decoders
     caused by write out-of-bound errors when using customized decode
     error handlers.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32889

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31356

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31356

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32305

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32303

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32711

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32583


File: python.info,  Node: Library<144>,  Next: Documentation<59>,  Prev: Core and Builtins<141>,  Up: Python 3 7 0 beta 2

1.23.69.3 Library
.................

   - bpo-32960(1): For dataclasses, disallow inheriting frozen from
     non-frozen classes, and also disallow inheriting non-frozen from
     frozen classes.  This restriction will be relaxed at a future date.

   - bpo-32713(2): Fixed tarfile.itn handling of out-of-bounds float
     values.  Patch by Joffrey Fuhrer.

   - bpo-32951(3): Direct instantiation of SSLSocket and SSLObject
     objects is now prohibited.  The constructors were never documented,
     tested, or designed as public constructors.  Users were suppose to
     use ssl.wrap_socket() or SSLContext.

   - bpo-32929(4): Remove the tri-state parameter “hash”, and add the
     boolean “unsafe_hash”.  If unsafe_hash is True, add a __hash__
     function, but if a __hash__ exists, raise TypeError.  If
     unsafe_hash is False, add a __hash__ based on the values of eq= and
     frozen=.  The unsafe_hash=False behavior is the same as the old
     hash=None behavior.  unsafe_hash=False is the default, just as
     hash=None used to be.

   - bpo-32947(5): Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround
     for TLSv1.3 for future compatibility with OpenSSL 1.1.1.

   - bpo-30622(6): The ssl module now detects missing NPN support in
     LibreSSL.

   - bpo-32922(7): dbm.open() now encodes filename with the filesystem
     encoding rather than default encoding.

   - bpo-32859(8): In ‘os.dup2’, don’t check every call whether the
     ‘dup3’ syscall exists or not.

   - bpo-32556(9): nt._getfinalpathname, nt._getvolumepathname and
     nt._getdiskusage now correctly convert from bytes.

   - bpo-25988(10): Emit a *note DeprecationWarning: 1a5. when using or
     importing an ABC directly from *note collections: 1d. rather than
     from *note collections.abc: 1e.

   - bpo-21060(11): Rewrite confusing message from setup.py upload from
     “No dist file created in earlier command” to the more helpful “Must
     create and upload files in one command”.

   - bpo-32852(12): Make sure sys.argv remains as a list when running
     trace.

   - bpo-31333(13): ‘_abc’ module is added.  It is a speedup module with
     C implementations for various functions and methods in ‘abc’.
     Creating an ABC subclass and calling ‘isinstance’ or ‘issubclass’
     with an ABC subclass are up to 1.5x faster.  In addition, this
     makes Python start-up up to 10% faster.  Note that the new
     implementation hides internal registry and caches, previously
     accessible via private attributes ‘_abc_registry’, ‘_abc_cache’,
     and ‘_abc_negative_cache’.  There are three debugging helper
     methods that can be used instead ‘_dump_registry’,
     ‘_abc_registry_clear’, and ‘_abc_caches_clear’.

   - bpo-32841(14): Fixed ‘asyncio.Condition’ issue which silently
     ignored cancellation after notifying and cancelling a conditional
     lock.  Patch by Bar Harel.

   - bpo-32819(15): ssl.match_hostname() has been simplified and no
     longer depends on re and ipaddress module for wildcard and IP
     addresses.  Error reporting for invalid wildcards has been
     improved.

   - bpo-32394(16): socket: Remove
     TCP_FASTOPEN,TCP_KEEPCNT,TCP_KEEPIDLE,TCP_KEEPINTVL flags on older
     version Windows during run-time.

   - bpo-31787(17): Fixed refleaks of ‘__init__()’ methods in various
     modules.  (Contributed by Oren Milman)

   - bpo-30157(18): Fixed guessing quote and delimiter in
     csv.Sniffer.sniff() when only the last field is quoted.  Patch by
     Jake Davis.

   - bpo-32792(19): collections.ChainMap() preserves the order of the
     underlying mappings.

   - bpo-32775(20): *note fnmatch.translate(): 1bd6. no longer produces
     patterns which contain set operations.  Sets starting with ‘[’ or
     containing ‘–’, ‘&&’, ‘~~’ or ‘||’ will be interpreted differently
     in regular expressions in future versions.  Currently they emit
     warnings.  fnmatch.translate() now avoids producing patterns
     containing such sets by accident.

   - bpo-32622(21): Implement native fast sendfile for Windows proactor
     event loop.

   - bpo-32777(22): Fix a rare but potential pre-exec child process
     deadlock in subprocess on POSIX systems when marking file
     descriptors inheritable on exec in the child process.  This bug
     appears to have been introduced in 3.4.

   - bpo-32647(23): The ctypes module used to depend on indirect linking
     for dlopen.  The shared extension is now explicitly linked against
     libdl on platforms with dl.

   - bpo-32741(24): Implement ‘asyncio.TimerHandle.when()’ method.

   - bpo-32691(25): Use mod_spec.parent when running modules with pdb

   - bpo-32734(26): Fixed ‘asyncio.Lock()’ safety issue which allowed
     acquiring and locking the same lock multiple times, without it
     being free.  Patch by Bar Harel.

   - bpo-32727(27): Do not include name field in SMTP envelope from
     address.  Patch by Stéphane Wirtel

   - bpo-31453(28): Add TLSVersion constants and
     SSLContext.maximum_version / minimum_version attributes.  The new
     API wraps OpenSSL 1.1
     ‘https://web.archive.org/web/20180309043602/https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_set_min_proto_version.html’
     feature.

   - bpo-24334(29): Internal implementation details of ssl module were
     cleaned up.  The SSLSocket has one less layer of indirection.
     Owner and session information are now handled by the SSLSocket and
     SSLObject constructor.  Channel binding implementation has been
     simplified.

   - bpo-31848(30): Fix the error handling in Aifc_read.initfp() when
     the SSND chunk is not found.  Patch by Zackery Spytz.

   - bpo-32585(31): Add Ttk spinbox widget to *note tkinter.ttk: f9.
     Patch by Alan D Moore.

   - bpo-32221(32): Various functions returning tuple containing IPv6
     addresses now omit ‘%scope’ part since the same information is
     already encoded in 'scopeid' tuple item.  Especially this speeds up
     ‘socket.recvfrom()’ when it receives multicast packet since useless
     resolving of network interface name is omitted.

   - bpo-30693(33): The TarFile class now recurses directories in a
     reproducible way.

   - bpo-30693(34): The ZipFile class now recurses directories in a
     reproducible way.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32960

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32713

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32951

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32929

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32947

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30622

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32922

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32859

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32556

   (10) https://bugs.python.org/issue?@action=redirect&bpo=25988

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21060

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32852

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31333

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32841

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32819

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32394

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31787

   (18) https://bugs.python.org/issue?@action=redirect&bpo=30157

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32792

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32775

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32622

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32777

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32647

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32741

   (25) https://bugs.python.org/issue?@action=redirect&bpo=32691

   (26) https://bugs.python.org/issue?@action=redirect&bpo=32734

   (27) https://bugs.python.org/issue?@action=redirect&bpo=32727

   (28) https://bugs.python.org/issue?@action=redirect&bpo=31453

   (29) https://bugs.python.org/issue?@action=redirect&bpo=24334

   (30) https://bugs.python.org/issue?@action=redirect&bpo=31848

   (31) https://bugs.python.org/issue?@action=redirect&bpo=32585

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32221

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30693

   (34) https://bugs.python.org/issue?@action=redirect&bpo=30693


File: python.info,  Node: Documentation<59>,  Next: Tests<60>,  Prev: Library<144>,  Up: Python 3 7 0 beta 2

1.23.69.4 Documentation
.......................

   - bpo-28124(1): The ssl module function ssl.wrap_socket() has been
     de-emphasized and deprecated in favor of the more secure and
     efficient SSLContext.wrap_socket() method.

   - bpo-17232(2): Clarify docs for -O and -OO. Patch by Terry Reedy.

   - bpo-32436(3): Add documentation for the contextvars module (PEP
     567).

   - bpo-32800(4): Update link to w3c doc for xml default namespaces.

   - bpo-11015(5): Update *note test.support: e4. documentation.

   - bpo-8722(6): Document ‘__getattr__()’ behavior when property
     ‘get()’ method raises *note AttributeError: 34e.

   - bpo-32614(7): Modify RE examples in documentation to use raw
     strings to prevent *note DeprecationWarning: 1a5. and add text to
     REGEX HOWTO to highlight the deprecation.

   - bpo-31972(8): Improve docstrings for ‘pathlib.PurePath’ subclasses.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28124

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17232

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32800

   (5) https://bugs.python.org/issue?@action=redirect&bpo=11015

   (6) https://bugs.python.org/issue?@action=redirect&bpo=8722

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32614

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31972


File: python.info,  Node: Tests<60>,  Next: Build<65>,  Prev: Documentation<59>,  Up: Python 3 7 0 beta 2

1.23.69.5 Tests
...............

   - bpo-31809(1): Add tests to verify connection with secp ECDH curves.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31809


File: python.info,  Node: Build<65>,  Next: Windows<57>,  Prev: Tests<60>,  Up: Python 3 7 0 beta 2

1.23.69.6 Build
...............

   - bpo-32898(1): Fix the python debug build when using COUNT_ALLOCS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32898


File: python.info,  Node: Windows<57>,  Next: macOS<46>,  Prev: Build<65>,  Up: Python 3 7 0 beta 2

1.23.69.7 Windows
.................

   - bpo-32901(1): Update Tcl and Tk versions to 8.6.8

   - bpo-31966(2): Fixed WindowsConsoleIO.write() for writing empty
     data.

   - bpo-32409(3): Ensures activate.bat can handle Unicode contents.

   - bpo-32457(4): Improves handling of denormalized executable path
     when launching Python.

   - bpo-32370(5): Use the correct encoding for ipconfig output in the
     uuid module.  Patch by Segev Finer.

   - bpo-29248(6): Fix *note os.readlink(): 929. on Windows, which was
     mistakenly treating the ‘PrintNameOffset’ field of the reparse data
     buffer as a number of characters instead of bytes.  Patch by Craig
     Holmquist and SSE4.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32901

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31966

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32409

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32457

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32370

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29248


File: python.info,  Node: macOS<46>,  Next: IDLE<46>,  Prev: Windows<57>,  Up: Python 3 7 0 beta 2

1.23.69.8 macOS
...............

   - bpo-32901(1): Update macOS 10.9+ installer to Tcl/Tk 8.6.8.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32901


File: python.info,  Node: IDLE<46>,  Next: Tools/Demos<33>,  Prev: macOS<46>,  Up: Python 3 7 0 beta 2

1.23.69.9 IDLE
..............

   - bpo-32916(1): Change ‘str’ to ‘code’ in pyparse.

   - bpo-32905(2): Remove unused code in pyparse module.

   - bpo-32874(3): Add tests for pyparse.

   - bpo-32837(4): Using the system and place-dependent default encoding
     for open() is a bad idea for IDLE’s system and location-independent
     files.

   - bpo-32826(5): Add “encoding=utf-8” to open() in IDLE’s
     test_help_about.  GUI test test_file_buttons() only looks at
     initial ascii-only lines, but failed on systems where open()
     defaults to ‘ascii’ because readline() internally reads and decodes
     far enough ahead to encounter a non-ascii character in CREDITS.txt.

   - bpo-32765(6): Update configdialog General tab docstring to add new
     widgets to the widget list.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32916

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32905

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32874

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32837

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32826

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32765


File: python.info,  Node: Tools/Demos<33>,  Prev: IDLE<46>,  Up: Python 3 7 0 beta 2

1.23.69.10 Tools/Demos
......................

   - bpo-32222(1): Fix pygettext not extracting docstrings for functions
     with type annotated arguments.  Patch by Toby Harradine.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32222


File: python.info,  Node: Python 3 7 0 beta 1,  Next: Python 3 7 0 alpha 4,  Prev: Python 3 7 0 beta 2,  Up: Changelog

1.23.70 Python 3.7.0 beta 1
---------------------------

'Release date: 2018-01-30'

* Menu:

* Core and Builtins: Core and Builtins<142>.
* Library: Library<145>.
* Documentation: Documentation<60>.
* Tests: Tests<61>.
* Build: Build<66>.
* Windows: Windows<58>.
* macOS: macOS<47>.
* C API: C API<58>.


File: python.info,  Node: Core and Builtins<142>,  Next: Library<145>,  Up: Python 3 7 0 beta 1

1.23.70.1 Core and Builtins
...........................

   - bpo-32703(1): Fix coroutine’s ResourceWarning when there’s an
     active error set when it’s being finalized.

   - bpo-32650(2): Pdb and other debuggers dependent on bdb.py will
     correctly step over (next command) native coroutines.  Patch by
     Pablo Galindo.

   - bpo-28685(3): Optimize list.sort() and sorted() by using type
     specialized comparisons when possible.

   - bpo-32685(4): Improve suggestion when the Python 2 form of print
     statement is either present on the same line as the header of a
     compound statement or else terminated by a semi-colon instead of a
     newline.  Patch by Nitish Chandra.

   - bpo-32697(5): Python now explicitly preserves the definition order
     of keyword-only parameters.  It’s always preserved their order, but
     this behavior was never guaranteed before; this behavior is now
     guaranteed and tested.

   - bpo-32690(6): The locals() dictionary now displays in the lexical
     order that variables were defined.  Previously, the order was
     reversed.

   - bpo-32677(7): Add ‘.isascii()’ method to ‘str’, ‘bytes’ and
     ‘bytearray’.  It can be used to test that string contains only
     ASCII characters.

   - bpo-32670(8): Enforce PEP 479(9) for all code.  This means that
     manually raising a StopIteration exception from a generator is
     prohibited for all code, regardless of whether ‘from __future__
     import generator_stop’ was used or not.

   - bpo-32591(10): Added built-in support for tracking the origin of
     coroutine objects; see sys.set_coroutine_origin_tracking_depth and
     CoroutineType.cr_origin.  This replaces the asyncio debug mode’s
     use of coroutine wrapping for native coroutine objects.

   - bpo-31368(11): Expose preadv and pwritev system calls in the os
     module.  Patch by Pablo Galindo

   - bpo-32544(12): ‘hasattr(obj, name)’ and ‘getattr(obj, name,
     default)’ are about 4 times faster than before when ‘name’ is not
     found and ‘obj’ doesn’t override ‘__getattr__’ or
     ‘__getattribute__’.

   - bpo-26163(13): Improved frozenset() hash to create more distinct
     hash values when faced with datasets containing many similar
     values.

   - bpo-32550(14): Remove the STORE_ANNOTATION bytecode.

   - bpo-20104(15): Expose posix_spawn as a low level API in the os
     module.  (removed before 3.7.0rc1)

   - bpo-24340(16): Fixed estimation of the code stack size.

   - bpo-32436(17): Implement PEP 567(18) Context Variables.

   - bpo-18533(19): ‘repr()’ on a dict containing its own ‘values()’ or
     ‘items()’ no longer raises ‘RecursionError’; OrderedDict similarly.
     Instead, use ‘...’, as for other recursive structures.  Patch by
     Ben North.

   - bpo-20891(20): Py_Initialize() now creates the GIL. The GIL is no
     longer created “on demand” to fix a race condition when
     PyGILState_Ensure() is called in a non-Python thread.

   - bpo-32028(21): Leading whitespace is now correctly ignored when
     generating suggestions for converting Py2 print statements to Py3
     builtin print function calls.  Patch by Sanyam Khurana.

   - bpo-31179(22): Make dict.copy() up to 5.5 times faster.

   - bpo-31113(23): Get rid of recursion in the compiler for normal
     control flow.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32703

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32650

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28685

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32685

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32697

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32690

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32677

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32670

   (9) https://peps.python.org/pep-0479/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32591

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31368

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32544

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26163

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32550

   (15) https://bugs.python.org/issue?@action=redirect&bpo=20104

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24340

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32436

   (18) https://peps.python.org/pep-0567/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=18533

   (20) https://bugs.python.org/issue?@action=redirect&bpo=20891

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32028

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31179

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31113


File: python.info,  Node: Library<145>,  Next: Documentation<60>,  Prev: Core and Builtins<142>,  Up: Python 3 7 0 beta 1

1.23.70.2 Library
.................

   - bpo-25988(1): Deprecate exposing the contents of collections.abc in
     the regular collections module.

   - bpo-31429(2): The default cipher suite selection of the ssl module
     now uses a blacklist approach rather than a hard-coded whitelist.
     Python no longer re-enables ciphers that have been blocked by
     OpenSSL security update.  Default cipher suite selection can be
     configured on compile time.

   - bpo-30306(3): contextlib.contextmanager now releases the arguments
     passed to the underlying generator as soon as the context manager
     is entered.  Previously it would keep them alive for as long as the
     context manager was alive, even when not being used as a function
     decorator.  Patch by Martin Teichmann.

   - bpo-21417(4): Added support for setting the compression level for
     zipfile.ZipFile.

   - bpo-32251(5): Implement asyncio.BufferedProtocol (provisional API).

   - bpo-32513(6): In dataclasses, allow easier overriding of dunder
     methods without specifying decorator parameters.

   - bpo-32660(7): *note termios: e1. makes available ‘FIONREAD’,
     ‘FIONCLEX’, ‘FIOCLEX’, ‘FIOASYNC’ and ‘FIONBIO’ also under
     Solaris/derivatives.

   - bpo-27931(8): Fix email address header parsing error when the
     username is an empty quoted string.  Patch by Xiang Zhang.

   - bpo-32659(9): Under Solaris and derivatives, *note os.stat_result:
     1510. provides a st_fstype attribute.

   - bpo-32662(10): Implement Server.start_serving(),
     Server.serve_forever(), and Server.is_serving() methods.  Add
     ‘start_serving’ keyword parameter to loop.create_server() and
     loop.create_unix_server().

   - bpo-32391(11): Implement *note asyncio.StreamWriter.wait_closed():
     b25. and *note asyncio.StreamWriter.is_closing(): b26. methods

   - bpo-32643(12): Make Task._step, Task._wakeup and
     Future._schedule_callbacks methods private.

   - bpo-32630(13): Refactor decimal module to use contextvars to store
     decimal context.

   - bpo-32622(14): Add ‘asyncio.AbstractEventLoop.sendfile()’ method.

   - bpo-32304(15): distutils’ upload command no longer corrupts tar
     files ending with a CR byte, and no longer tries to convert CR to
     CRLF in any of the upload text fields.

   - bpo-32502(16): uuid.uuid1 no longer raises an exception if a 64-bit
     hardware address is encountered.

   - bpo-32596(17): ‘concurrent.futures’ imports ‘ThreadPoolExecutor’
     and ‘ProcessPoolExecutor’ lazily (using PEP 562(18)).  It makes
     ‘import asyncio’ about 15% faster because asyncio uses only
     ‘ThreadPoolExecutor’ by default.

   - bpo-31801(19): Add ‘_ignore_’ to ‘Enum’ so temporary variables can
     be used during class construction without being turned into
     members.

   - bpo-32576(20): Use queue.SimpleQueue() in places where it can be
     invoked from a weakref callback.

   - bpo-32574(21): Fix memory leak in asyncio.Queue, when the queue has
     limited size and it is full, the cancelation of queue.put() can
     cause a memory leak.  Patch by: José Melero.

   - bpo-32521(22): The nis module is now compatible with new libnsl and
     headers location.

   - bpo-32467(23): collections.abc.ValuesView now inherits from
     collections.abc.Collection.

   - bpo-32473(24): Improve ABCMeta._dump_registry() output readability

   - bpo-32102(25): New argument ‘capture_output’ for subprocess.run

   - bpo-32521(26): glibc has removed Sun RPC. Use replacement libtirpc
     headers and library in nis module.

   - bpo-32493(27): UUID module fixes build for FreeBSD/OpenBSD

   - bpo-32503(28): Pickling with protocol 4 no longer creates too small
     frames.

   - bpo-29237(29): Create enum for pstats sorting options

   - bpo-32454(30): Add close(fd) function to the socket module.

   - bpo-25942(31): The subprocess module is now more graceful when
     handling a Ctrl-C KeyboardInterrupt during subprocess.call,
     subprocess.run, or a Popen context manager.  It now waits a short
     amount of time for the child (presumed to have also gotten the
     SIGINT) to exit, before continuing the KeyboardInterrupt exception
     handling.  This still includes a SIGKILL in the call() and run()
     APIs, but at least the child had a chance first.

   - bpo-32433(32): The hmac module now has hmac.digest(), which
     provides an optimized HMAC digest.

   - bpo-28134(33): Sockets now auto-detect family, type and protocol
     from file descriptor by default.

   - bpo-32404(34): Fix bug where *note
     datetime.datetime.fromtimestamp(): 4f0. did not call __new__ in
     *note datetime.datetime: 1cc. subclasses.

   - bpo-32403(35): Improved speed of *note datetime.date: 1cd. and
     *note datetime.datetime: 1cc. alternate constructors.

   - bpo-32228(36): Ensure that ‘truncate()’ preserves the file position
     (as reported by ‘tell()’) after writes longer than the buffer size.

   - bpo-32410(37): Implement ‘loop.sock_sendfile’ for asyncio event
     loop.

   - bpo-22908(38): Added seek and tell to the ZipExtFile class.  This
     only works if the file object used to open the zipfile is seekable.

   - bpo-32373(39): Add socket.getblocking() method.

   - bpo-32248(40): Add *note importlib.resources: 7b. and *note
     importlib.abc.ResourceReader: b16. as the unified API for reading
     resources contained within packages.  Loaders wishing to support
     resource reading must implement the ‘get_resource_reader()’ method.
     File-based and zipimport-based loaders both implement these APIs.
     *note importlib.abc.ResourceLoader: c08. is deprecated in favor of
     these new APIs.

   - bpo-32320(41): collections.namedtuple() now supports default
     values.

   - bpo-29302(42): Add contextlib.AsyncExitStack.  Patch by Alexander
     Mohr and Ilya Kulakov.

   - bpo-31961(43): 'Removed in Python 3.7.0b2.'  The 'args' argument of
     subprocess.Popen can now be a *note path-like object: 2a0.  If
     'args' is given as a sequence, it’s first element can now be a
     path-like object as well.

   - bpo-31900(44): The *note locale.localeconv(): c1e. function now
     sets temporarily the ‘LC_CTYPE’ locale to the ‘LC_NUMERIC’ locale
     to decode ‘decimal_point’ and ‘thousands_sep’ byte strings if they
     are non-ASCII or longer than 1 byte, and the ‘LC_NUMERIC’ locale is
     different than the ‘LC_CTYPE’ locale.  This temporary change
     affects other threads.  Same change for the *note str.format():
     624. method when formatting a number (*note int: 257, *note float:
     2f7, ‘float’ and subclasses) with the ‘n’ type (ex:
     ‘'{:n}'.format(1234)’).

   - bpo-31853(45): Use super().method instead of socket.method in
     SSLSocket.  They were there most likely for legacy reasons.

   - bpo-31399(46): The ssl module now uses OpenSSL’s
     X509_VERIFY_PARAM_set1_host() and X509_VERIFY_PARAM_set1_ip() API
     to verify hostname and IP addresses.  Subject common name fallback
     can be disabled with SSLContext.hostname_checks_common_name.

   - bpo-14976(47): Add a queue.SimpleQueue class, an unbounded FIFO
     queue with a reentrant C implementation of put().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25988

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31429

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30306

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21417

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32251

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32513

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32660

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27931

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32659

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32662

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32391

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32643

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32630

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32622

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32304

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32502

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32596

   (18) https://peps.python.org/pep-0562/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31801

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32576

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32574

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32521

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32467

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32473

   (25) https://bugs.python.org/issue?@action=redirect&bpo=32102

   (26) https://bugs.python.org/issue?@action=redirect&bpo=32521

   (27) https://bugs.python.org/issue?@action=redirect&bpo=32493

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32503

   (29) https://bugs.python.org/issue?@action=redirect&bpo=29237

   (30) https://bugs.python.org/issue?@action=redirect&bpo=32454

   (31) https://bugs.python.org/issue?@action=redirect&bpo=25942

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32433

   (33) https://bugs.python.org/issue?@action=redirect&bpo=28134

   (34) https://bugs.python.org/issue?@action=redirect&bpo=32404

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32403

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32228

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32410

   (38) https://bugs.python.org/issue?@action=redirect&bpo=22908

   (39) https://bugs.python.org/issue?@action=redirect&bpo=32373

   (40) https://bugs.python.org/issue?@action=redirect&bpo=32248

   (41) https://bugs.python.org/issue?@action=redirect&bpo=32320

   (42) https://bugs.python.org/issue?@action=redirect&bpo=29302

   (43) https://bugs.python.org/issue?@action=redirect&bpo=31961

   (44) https://bugs.python.org/issue?@action=redirect&bpo=31900

   (45) https://bugs.python.org/issue?@action=redirect&bpo=31853

   (46) https://bugs.python.org/issue?@action=redirect&bpo=31399

   (47) https://bugs.python.org/issue?@action=redirect&bpo=14976


File: python.info,  Node: Documentation<60>,  Next: Tests<61>,  Prev: Library<145>,  Up: Python 3 7 0 beta 1

1.23.70.3 Documentation
.......................

   - bpo-32724(1): Add references to some commands in the documentation
     of Pdb.  Patch by Stéphane Wirtel

   - bpo-32649(2): Complete the C API documentation, profiling and
     tracing part with the newly added per-opcode events.

   - bpo-17799(3): Explain real behaviour of sys.settrace and
     sys.setprofile and their C-API counterparts regarding which type of
     events are received in each function.  Patch by Pablo Galindo
     Salgado.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32724

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17799


File: python.info,  Node: Tests<61>,  Next: Build<66>,  Prev: Documentation<60>,  Up: Python 3 7 0 beta 1

1.23.70.4 Tests
...............

   - bpo-32721(1): Fix test_hashlib to not fail if the _md5 module is
     not built.

   - bpo-28414(2): Add test cases for IDNA 2003 and 2008 host names.
     IDNA 2003 internationalized host names are working since
     bpo-31399(3) has landed.  IDNA 2008 are still broken.

   - bpo-32604(4): Add a new “_xxsubinterpreters” extension module that
     exposes the existing subinterpreter C-API and a new
     cross-interpreter data sharing mechanism.  The module is primarily
     intended for more thorough testing of the existing subinterpreter
     support.  Note that the _xxsubinterpreters module has been removed
     in 3.7.0rc1.

   - bpo-32602(5): Add test certs and test for ECDSA cert and EC/RSA
     dual mode.

   - bpo-32549(6): On Travis CI, Python now Compiles and uses a local
     copy of OpenSSL 1.1.0g for testing.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32721

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28414

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31399

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32604

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32602

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32549


File: python.info,  Node: Build<66>,  Next: Windows<58>,  Prev: Tests<61>,  Up: Python 3 7 0 beta 1

1.23.70.5 Build
...............

   - bpo-32635(1): Fix segfault of the crypt module when libxcrypt is
     provided instead of libcrypt at the system.

   - bpo-32598(2): Use autoconf to detect OpenSSL libs, headers and
     supported features.  The ax_check_openssl M4 macro uses pkg-config
     to locate OpenSSL and falls back to manual search.

   - bpo-32593(3): Drop support of FreeBSD 9 and older.

   - bpo-29708(4): If the ‘SOURCE_DATE_EPOCH’ environment variable is
     set, *note py_compile: b3. will always create hash-based ‘.pyc’
     files.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32635

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32598

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32593

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29708


File: python.info,  Node: Windows<58>,  Next: macOS<47>,  Prev: Build<66>,  Up: Python 3 7 0 beta 1

1.23.70.6 Windows
.................

   - bpo-32588(1): Create standalone _distutils_findvs module and add
     missing _queue module to installer.

   - bpo-29911(2): Ensure separate Modify and Uninstall buttons are
     displayed.

   - bpo-32507(3): Use app-local UCRT install rather than the proper
     update for old versions of Windows.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32588

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29911

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32507


File: python.info,  Node: macOS<47>,  Next: C API<58>,  Prev: Windows<58>,  Up: Python 3 7 0 beta 1

1.23.70.7 macOS
...............

   - bpo-32726(1): Provide an additional, more modern macOS installer
     variant that supports macOS 10.9+ systems in 64-bit mode only.
     Upgrade the supplied third-party libraries to OpenSSL 1.1.0g and to
     SQLite 3.22.0.  The 10.9+ installer now links with and supplies its
     own copy of Tcl/Tk 8.6.

   - bpo-28440(2): No longer add /Library/Python/3.x/site-packages to
     sys.path for macOS framework builds to avoid future conflicts.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32726

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28440


File: python.info,  Node: C API<58>,  Prev: macOS<47>,  Up: Python 3 7 0 beta 1

1.23.70.8 C API
...............

   - bpo-32681(1): Fix uninitialized variable ‘res’ in the C
     implementation of os.dup2.  Patch by Stéphane Wirtel

   - bpo-10381(2): Add C API access to the ‘datetime.timezone’
     constructor and ‘datetime.timzone.UTC’ singleton.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32681

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10381


File: python.info,  Node: Python 3 7 0 alpha 4,  Next: Python 3 7 0 alpha 3,  Prev: Python 3 7 0 beta 1,  Up: Changelog

1.23.71 Python 3.7.0 alpha 4
----------------------------

'Release date: 2018-01-08'

* Menu:

* Core and Builtins: Core and Builtins<143>.
* Library: Library<146>.
* Documentation: Documentation<61>.
* Tests: Tests<62>.
* Windows: Windows<59>.
* Tools/Demos: Tools/Demos<34>.
* C API: C API<59>.


File: python.info,  Node: Core and Builtins<143>,  Next: Library<146>,  Up: Python 3 7 0 alpha 4

1.23.71.1 Core and Builtins
...........................

   - bpo-31975(1): The default warning filter list now starts with a
     “default::DeprecationWarning:__main__” entry, so deprecation
     warnings are once again shown by default in single-file scripts and
     at the interactive prompt.

   - bpo-32226(2): ‘__class_getitem__’ is now an automatic class method.

   - bpo-32399(3): Add AIX uuid library support for RFC4122 using
     uuid_create() in libc.a

   - bpo-32390(4): Fix the compilation failure on AIX after the f_fsid
     field has been added to the object returned by os.statvfs()
     (bpo-32143(5)).  Original patch by Michael Felt.

   - bpo-32379(6): Make MRO computation faster when a class inherits
     from a single base.

   - bpo-32259(7): The error message of a TypeError raised when unpack
     non-iterable is now more specific.

   - bpo-27169(8): The ‘__debug__’ constant is now optimized out at
     compile time.  This fixes also bpo-22091(9).

   - bpo-32329(10): The *note -R: 1c29. option now turns on hash
     randomization when the *note PYTHONHASHSEED: 10bb. environment
     variable is set to ‘0’.  Previously, the option was ignored.
     Moreover, ‘sys.flags.hash_randomization’ is now properly set to 0
     when hash randomization is turned off by ‘PYTHONHASHSEED=0’.

   - bpo-30416(11): The optimizer is now protected from spending much
     time doing complex calculations and consuming much memory for
     creating large constants in constant folding.  Increased limits for
     constants that can be produced in constant folding.

   - bpo-32282(12): Fix an unnecessary ifdef in the include of
     VersionHelpers.h in socketmodule on Windows.

   - bpo-30579(13): Implement TracebackType.__new__ to allow
     Python-level creation of traceback objects, and make
     TracebackType.tb_next mutable.

   - bpo-32260(14): Don’t byte swap the input keys to the SipHash
     algorithm on big-endian platforms.  This should ensure siphash
     gives consistent results across platforms.

   - bpo-31506(15): Improve the error message logic for object.__new__
     and object.__init__.  Patch by Sanyam Khurana.

   - bpo-20361(16): ‘-b’ and ‘-bb’ now inject ‘'default::BytesWarning'’
     and ‘error::BytesWarning’ entries into ‘sys.warnoptions’, ensuring
     that they take precedence over any other warning filters configured
     via the ‘-W’ option or the ‘PYTHONWARNINGS’ environment variable.

   - bpo-32230(17): ‘-X dev’ now injects a ‘'default'’ entry into
     sys.warnoptions, ensuring that it behaves identically to actually
     passing ‘-Wdefault’ at the command line.

   - bpo-29240(18): Add a new UTF-8 mode: implementation of the PEP
     540(19).

   - bpo-32226(20): PEP 560(21): Add support for ‘__mro_entries__’ and
     ‘__class_getitem__’.  Implemented by Ivan Levkivskyi.

   - bpo-32225(22): PEP 562(23): Add support for module ‘__getattr__’
     and ‘__dir__’.  Implemented by Ivan Levkivskyi.

   - bpo-31901(24): The ‘atexit’ module now has its callback stored per
     interpreter.

   - bpo-31650(25): Implement PEP 552(26) (Deterministic pycs).  Python
     now supports invalidating bytecode cache files bashed on a source
     content hash rather than source last-modified time.

   - bpo-29469(27): Move constant folding from bytecode layer to AST
     layer.  Original patch by Eugene Toder.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31975

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32226

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32399

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32390

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32143

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32379

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32259

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27169

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22091

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32329

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30416

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32282

   (13) https://bugs.python.org/issue?@action=redirect&bpo=30579

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32260

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31506

   (16) https://bugs.python.org/issue?@action=redirect&bpo=20361

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32230

   (18) https://bugs.python.org/issue?@action=redirect&bpo=29240

   (19) https://peps.python.org/pep-0540/

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32226

   (21) https://peps.python.org/pep-0560/

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32225

   (23) https://peps.python.org/pep-0562/

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31901

   (25) https://bugs.python.org/issue?@action=redirect&bpo=31650

   (26) https://peps.python.org/pep-0552/

   (27) https://bugs.python.org/issue?@action=redirect&bpo=29469


File: python.info,  Node: Library<146>,  Next: Documentation<61>,  Prev: Core and Builtins<143>,  Up: Python 3 7 0 alpha 4

1.23.71.2 Library
.................

   - bpo-32506(1): Now that dict is defined as keeping insertion order,
     drop OrderedDict and just use plain dict.

   - bpo-32279(2): Add params to dataclasses.make_dataclasses(): init,
     repr, eq, order, hash, and frozen.  Pass them through to
     dataclass().

   - bpo-32278(3): Make type information optional on
     dataclasses.make_dataclass().  If omitted, the string ‘typing.Any’
     is used.

   - bpo-32499(4): Add dataclasses.is_dataclass(obj), which returns True
     if obj is a dataclass or an instance of one.

   - bpo-32468(5): Improve frame repr() to mention filename, code name
     and current line number.

   - bpo-23749(6): asyncio: Implement loop.start_tls()

   - bpo-32441(7): Return the new file descriptor (i.e., the second
     argument) from ‘os.dup2’.  Previously, ‘None’ was always returned.

   - bpo-32422(8): ‘functools.lru_cache’ uses less memory (3 words for
     each cached key) and takes about 1/3 time for cyclic GC.

   - bpo-31721(9): Prevent Python crash from happening when
     Future._log_traceback is set to True manually.  Now it can only be
     set to False, or a ValueError is raised.

   - bpo-32415(10): asyncio: Add Task.get_loop() and Future.get_loop()

   - bpo-26133(11): Don’t unsubscribe signals in asyncio UNIX event loop
     on interpreter shutdown.

   - bpo-32363(12): Make asyncio.Task.set_exception() and set_result()
     raise NotImplementedError.  Task._step() and Future.__await__()
     raise proper exceptions when they are in an invalid state, instead
     of raising an AssertionError.

   - bpo-32357(13): Optimize asyncio.iscoroutine() and
     loop.create_task() for non-native coroutines (e.g.  async/await
     compiled with Cython).  ‘loop.create_task(python_coroutine)’ used
     to be 20% faster than ‘loop.create_task(cython_coroutine)’.  Now,
     the latter is as fast.

   - bpo-32356(14): asyncio.transport.resume_reading() and
     pause_reading() are now idempotent.  New transport.is_reading()
     method is added.

   - bpo-32355(15): Optimize asyncio.gather(); now up to 15% faster.

   - bpo-32351(16): Use fastpath in asyncio.sleep if delay<0 (2x boost)

   - bpo-32348(17): Optimize asyncio.Future schedule/add/remove
     callback.  The optimization shows 3-6% performance improvements of
     async/await code.

   - bpo-32331(18): Fix socket.settimeout() and socket.setblocking() to
     keep socket.type as is.  Fix socket.socket() constructor to reset
     any bit flags applied to socket’s type.  This change only affects
     OSes that have SOCK_NONBLOCK and/or SOCK_CLOEXEC.

   - bpo-32248(19): Add *note importlib.abc.ResourceReader: b16. as an
     ABC for loaders to provide a unified API for reading resources
     contained within packages.  Also add *note importlib.resources: 7b.
     as the port of ‘importlib_resources’.

   - bpo-32311(20): Implement asyncio.create_task(coro) shortcut

   - bpo-32327(21): Convert asyncio functions that were documented as
     coroutines to coroutines.  Affected functions: loop.sock_sendall,
     loop.sock_recv, loop.sock_accept, loop.getaddrinfo,
     loop.getnameinfo.

   - bpo-32323(22): *note urllib.parse.urlsplit(): d67. does not convert
     zone-id (scope) to lower case for scoped IPv6 addresses in
     hostnames now.

   - bpo-32302(23): Fix bdist_wininst of distutils for CRT v142: it
     binary compatible with CRT v140.

   - bpo-29711(24): Fix ‘stop_serving’ in asyncio proactor loop kill all
     listening servers

   - bpo-32308(25): *note re.sub(): 2a3. now replaces empty matches
     adjacent to a previous non-empty match.

   - bpo-29970(26): Abort asyncio SSLProtocol connection if handshake
     not complete within 10 seconds.

   - bpo-32314(27): Implement asyncio.run().

   - bpo-17852(28): Revert incorrect fix based on misunderstanding of
     _Py_PyAtExit() semantics.

   - bpo-32296(29): Implement asyncio._get_running_loop() and
     get_event_loop() in C. This makes them 4x faster.

   - bpo-32250(30): Implement ‘asyncio.current_task()’ and
     ‘asyncio.all_tasks()’.  Add helpers intended to be used by
     alternative task implementations: ‘asyncio._register_task’,
     ‘asyncio._enter_task’, ‘asyncio._leave_task’ and
     ‘asyncio._unregister_task’.  Deprecate
     ‘asyncio.Task.current_task()’ and ‘asyncio.Task.all_tasks()’.

   - bpo-32255(31): A single empty field is now always quoted when
     written into a CSV file.  This allows to distinguish an empty row
     from a row consisting of a single empty field.  Patch by Licht
     Takeuchi.

   - bpo-32277(32): Raise ‘NotImplementedError’ instead of ‘SystemError’
     on platforms where ‘chmod(..., follow_symlinks=False)’ is not
     supported.  Patch by Anthony Sottile.

   - bpo-30050(33): New argument warn_on_full_buffer to
     signal.set_wakeup_fd lets you control whether Python prints a
     warning on stderr when the wakeup fd buffer overflows.

   - bpo-29137(34): The ‘fpectl’ library has been removed.  It was never
     enabled by default, never worked correctly on x86-64, and it
     changed the Python ABI in ways that caused unexpected breakage of C
     extensions.

   - bpo-32273(35): Move asyncio.test_utils to test.test_asyncio.

   - bpo-32272(36): Remove asyncio.async() function.

   - bpo-32269(37): Add asyncio.get_running_loop() function.

   - bpo-32265(38): All class and static methods of builtin types now
     are correctly classified by inspect.classify_class_attrs() and
     grouped in pydoc ouput.  Added types.ClassMethodDescriptorType for
     unbound class methods of builtin types.

   - bpo-32253(39): Deprecate ‘yield from lock’, ‘await lock’, ‘with
     (yield from lock)’ and ‘with await lock’ for asyncio
     synchronization primitives.

   - bpo-22589(40): Changed MIME type of .bmp from ‘image/x-ms-bmp’ to
     ‘image/bmp’

   - bpo-32193(41): Convert asyncio to use 'async/await' syntax.  Old
     styled ‘yield from’ is still supported too.

   - bpo-32206(42): Add support to run modules with pdb

   - bpo-32227(43): ‘functools.singledispatch’ now supports registering
     implementations using type annotations.

   - bpo-15873(44): Added new alternate constructors *note
     datetime.datetime.fromisoformat(): 61a, *note
     datetime.time.fromisoformat(): 619. and *note
     datetime.date.fromisoformat(): 618. as the inverse operation of
     each classes’s respective ‘isoformat’ methods.

   - bpo-32199(45): The getnode() ip getter now uses ‘ip link’ instead
     of ‘ip link list’.

   - bpo-32143(46): os.statvfs() includes the f_fsid field from
     statvfs(2)

   - bpo-26439(47): Fix ctypes.util.find_library() for AIX by
     implementing ctypes._aix.find_library() Patch by: Michael Felt

   - bpo-31993(48): The pickler now uses less memory when serializing
     large bytes and str objects into a file.  Pickles created with
     protocol 4 will require less memory for unpickling large bytes and
     str objects.

   - bpo-27456(49): Ensure TCP_NODELAY is set on Linux.  Tests by Victor
     Stinner.

   - bpo-31778(50): ast.literal_eval() is now more strict.  Addition and
     subtraction of arbitrary numbers no longer allowed.

   - bpo-31802(51): Importing native path module (‘posixpath’, ‘ntpath’)
     now works even if the ‘os’ module still is not imported.

   - bpo-30241(52): Add contextlib.AbstractAsyncContextManager.  Patch
     by Jelle Zijlstra.

   - bpo-31699(53): Fix deadlocks in *note
     concurrent.futures.ProcessPoolExecutor: 8f7. when task arguments or
     results cause pickling or unpickling errors.  This should make sure
     that calls to the ‘ProcessPoolExecutor’ API always eventually
     return.

   - bpo-15216(54): ‘TextIOWrapper.reconfigure()’ supports changing
     'encoding', 'errors', and 'newline'.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32506

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32279

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32278

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32499

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32468

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23749

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32441

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32422

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31721

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32415

   (11) https://bugs.python.org/issue?@action=redirect&bpo=26133

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32363

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32357

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32356

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32355

   (16) https://bugs.python.org/issue?@action=redirect&bpo=32351

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32348

   (18) https://bugs.python.org/issue?@action=redirect&bpo=32331

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32248

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32311

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32327

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32323

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32302

   (24) https://bugs.python.org/issue?@action=redirect&bpo=29711

   (25) https://bugs.python.org/issue?@action=redirect&bpo=32308

   (26) https://bugs.python.org/issue?@action=redirect&bpo=29970

   (27) https://bugs.python.org/issue?@action=redirect&bpo=32314

   (28) https://bugs.python.org/issue?@action=redirect&bpo=17852

   (29) https://bugs.python.org/issue?@action=redirect&bpo=32296

   (30) https://bugs.python.org/issue?@action=redirect&bpo=32250

   (31) https://bugs.python.org/issue?@action=redirect&bpo=32255

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32277

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30050

   (34) https://bugs.python.org/issue?@action=redirect&bpo=29137

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32273

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32272

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32269

   (38) https://bugs.python.org/issue?@action=redirect&bpo=32265

   (39) https://bugs.python.org/issue?@action=redirect&bpo=32253

   (40) https://bugs.python.org/issue?@action=redirect&bpo=22589

   (41) https://bugs.python.org/issue?@action=redirect&bpo=32193

   (42) https://bugs.python.org/issue?@action=redirect&bpo=32206

   (43) https://bugs.python.org/issue?@action=redirect&bpo=32227

   (44) https://bugs.python.org/issue?@action=redirect&bpo=15873

   (45) https://bugs.python.org/issue?@action=redirect&bpo=32199

   (46) https://bugs.python.org/issue?@action=redirect&bpo=32143

   (47) https://bugs.python.org/issue?@action=redirect&bpo=26439

   (48) https://bugs.python.org/issue?@action=redirect&bpo=31993

   (49) https://bugs.python.org/issue?@action=redirect&bpo=27456

   (50) https://bugs.python.org/issue?@action=redirect&bpo=31778

   (51) https://bugs.python.org/issue?@action=redirect&bpo=31802

   (52) https://bugs.python.org/issue?@action=redirect&bpo=30241

   (53) https://bugs.python.org/issue?@action=redirect&bpo=31699

   (54) https://bugs.python.org/issue?@action=redirect&bpo=15216


File: python.info,  Node: Documentation<61>,  Next: Tests<62>,  Prev: Library<146>,  Up: Python 3 7 0 alpha 4

1.23.71.3 Documentation
.......................

   - bpo-32418(1): Add get_loop() method to Server and AbstractServer
     classes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32418


File: python.info,  Node: Tests<62>,  Next: Windows<59>,  Prev: Documentation<61>,  Up: Python 3 7 0 alpha 4

1.23.71.4 Tests
...............

   - bpo-32252(1): Fix faulthandler_suppress_crash_report() used to
     prevent core dump files when testing crashes.  getrlimit() returns
     zero on success.

   - bpo-32002(2): Adjust C locale coercion testing for the empty locale
     and POSIX locale cases to more readily adjust to platform dependent
     behaviour.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32252

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32002


File: python.info,  Node: Windows<59>,  Next: Tools/Demos<34>,  Prev: Tests<62>,  Up: Python 3 7 0 alpha 4

1.23.71.5 Windows
.................

   - bpo-19764(1): Implement support for
     ‘subprocess.Popen(close_fds=True)’ on Windows.  Patch by Segev
     Finer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19764


File: python.info,  Node: Tools/Demos<34>,  Next: C API<59>,  Prev: Windows<59>,  Up: Python 3 7 0 alpha 4

1.23.71.6 Tools/Demos
.....................

   - bpo-24960(1): 2to3 and lib2to3 can now read pickled grammar files
     using pkgutil.get_data() rather than probing the filesystem.  This
     lets 2to3 and lib2to3 work when run from a zipfile.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24960


File: python.info,  Node: C API<59>,  Prev: Tools/Demos<34>,  Up: Python 3 7 0 alpha 4

1.23.71.7 C API
...............

   - bpo-32030(1): Py_Initialize() doesn’t reset the memory allocators
     to default if the ‘PYTHONMALLOC’ environment variable is not set.

   - bpo-29084(2): Undocumented C API for OrderedDict has been excluded
     from the limited C API. It was added by mistake and actually never
     worked in the limited C API.

   - bpo-32264(3): Moved the pygetopt.h header into internal/, since it
     has no public APIs.

   - bpo-32241(4): ‘Py_SetProgramName()’ and ‘Py_SetPythonHome()’ now
     take the ‘const wchar *’ arguments instead of ‘wchar *’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32030

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29084

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32264

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32241


File: python.info,  Node: Python 3 7 0 alpha 3,  Next: Python 3 7 0 alpha 2,  Prev: Python 3 7 0 alpha 4,  Up: Changelog

1.23.72 Python 3.7.0 alpha 3
----------------------------

'Release date: 2017-12-05'

* Menu:

* Core and Builtins: Core and Builtins<144>.
* Library: Library<147>.
* Documentation: Documentation<62>.
* Tests: Tests<63>.
* Build: Build<67>.
* Windows: Windows<60>.
* macOS: macOS<48>.
* IDLE: IDLE<47>.
* Tools/Demos: Tools/Demos<35>.
* C API: C API<60>.


File: python.info,  Node: Core and Builtins<144>,  Next: Library<147>,  Up: Python 3 7 0 alpha 3

1.23.72.1 Core and Builtins
...........................

   - bpo-32176(1): co_flags.CO_NOFREE is now always set correctly by the
     code object constructor based on freevars and cellvars, rather than
     needing to be set correctly by the caller.  This ensures it will be
     cleared automatically when additional cell references are injected
     into a modified code object and function.

   - bpo-10544(2): Yield expressions are now deprecated in
     comprehensions and generator expressions.  They are still permitted
     in the definition of the outermost iterable, as that is evaluated
     directly in the enclosing scope.

   - bpo-32137(3): The repr of deeply nested dict now raises a
     RecursionError instead of crashing due to a stack overflow.

   - bpo-32096(4): Revert memory allocator changes in the C API: move
     structures back from _PyRuntime to Objects/obmalloc.c.  The memory
     allocators are once again initialized statically, and so
     PyMem_RawMalloc() and Py_DecodeLocale() can be called before
     _PyRuntime_Initialize().

   - bpo-32043(5): Add a new “developer mode”: new “-X dev” command line
     option to enable debug checks at runtime.

   - bpo-32023(6): SyntaxError is now correctly raised when a generator
     expression without parenthesis is used instead of an inheritance
     list in a class definition.  The duplication of the parentheses can
     be omitted only on calls.

   - bpo-32012(7): SyntaxError is now correctly raised when a generator
     expression without parenthesis is passed as an argument, but
     followed by a trailing comma.  A generator expression always needs
     to be directly inside a set of parentheses and cannot have a comma
     on either side.

   - bpo-28180(8): A new internal ‘_Py_SetLocaleFromEnv(category)’
     helper function has been added in order to improve the consistency
     of behaviour across different ‘libc’ implementations (e.g.  Android
     doesn’t support setting the locale from the environment by
     default).

   - bpo-31949(9): Fixed several issues in printing tracebacks
     (PyTraceBack_Print()).  Setting sys.tracebacklimit to 0 or less now
     suppresses printing tracebacks.  Setting sys.tracebacklimit to None
     now causes using the default limit.  Setting sys.tracebacklimit to
     an integer larger than LONG_MAX now means using the limit LONG_MAX
     rather than the default limit.  Fixed integer overflows in the case
     of more than ‘2**31’ traceback items on Windows.  Fixed output
     errors handling.

   - bpo-30696(10): Fix the interactive interpreter looping endlessly
     when no memory.

   - bpo-20047(11): Bytearray methods partition() and rpartition() now
     accept only bytes-like objects as separator, as documented.  In
     particular they now raise TypeError rather of returning a bogus
     result when an integer is passed as a separator.

   - bpo-21720(12): BytesWarning no longer emitted when the 'fromlist'
     argument of ‘__import__()’ or the ‘__all__’ attribute of the module
     contain bytes instances.

   - bpo-31845(13): Environment variables are once more read correctly
     at interpreter startup.

   - bpo-28936(14): Ensure that lexically first syntax error involving a
     parameter and ‘global’ or ‘nonlocal’ is detected first at a given
     scope.  Patch by Ivan Levkivskyi.

   - bpo-31825(15): Fixed OverflowError in the ‘unicode-escape’ codec
     and in codecs.escape_decode() when decode an escaped non-ascii
     byte.

   - bpo-31618(16): The per-frame tracing logic added in 3.7a1 has been
     altered so that ‘frame->f_lineno’ is updated before either ‘"line"’
     or ‘"opcode"’ events are emitted.  Previously, opcode events were
     emitted first, and therefore would occasionally see stale line
     numbers on the frame.  The behavior of this feature has changed
     slightly as a result: when both ‘f_trace_lines’ and
     ‘f_trace_opcodes’ are enabled, line events now occur first.

   - bpo-28603(17): Print the full context/cause chain of exceptions on
     interpreter exit, even if an exception in the chain is unhashable
     or compares equal to later ones.  Patch by Zane Bitter.

   - bpo-31786(18): Fix timeout rounding in the select module to round
     correctly negative timeouts between -1.0 and 0.0.  The functions
     now block waiting for events as expected.  Previously, the call was
     incorrectly non-blocking.  Patch by Pablo Galindo.

   - bpo-31781(19): Prevent crashes when calling methods of an
     uninitialized ‘zipimport.zipimporter’ object.  Patch by Oren
     Milman.

   - bpo-30399(20): Standard repr() of BaseException with a single
     argument no longer contains redundant trailing comma.

   - bpo-31626(21): Fixed a bug in debug memory allocator.  There was a
     write to freed memory after shrinking a memory block.

   - bpo-30817(22): ‘PyErr_PrintEx()’ clears now the ignored exception
     that may be raised by ‘_PySys_SetObjectId()’, for example when no
     memory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32176

   (2) https://bugs.python.org/issue?@action=redirect&bpo=10544

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32137

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32096

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32043

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32023

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32012

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28180

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31949

   (10) https://bugs.python.org/issue?@action=redirect&bpo=30696

   (11) https://bugs.python.org/issue?@action=redirect&bpo=20047

   (12) https://bugs.python.org/issue?@action=redirect&bpo=21720

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31845

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28936

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31825

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31618

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31786

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31781

   (20) https://bugs.python.org/issue?@action=redirect&bpo=30399

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31626

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30817


File: python.info,  Node: Library<147>,  Next: Documentation<62>,  Prev: Core and Builtins<144>,  Up: Python 3 7 0 alpha 3

1.23.72.2 Library
.................

   - bpo-28556(1): Two minor fixes for ‘typing’ module: allow shallow
     copying instances of generic classes, improve interaction of
     ‘__init_subclass__’ with generics.  Original PRs by Ivan
     Levkivskyi.

   - bpo-32214(2): PEP 557, Data Classes.  Provides a decorator which
     adds boilerplate methods to classes which use type annotations so
     specify fields.

   - bpo-27240(3): The header folding algorithm for the new email
     policies has been rewritten, which also fixes bpo-30788(4),
     bpo-31831(5), and bpo-32182(6).  In particular, RFC2231 folding is
     now done correctly.

   - bpo-32186(7): io.FileIO.readall() and io.FileIO.read() now release
     the GIL when getting the file size.  Fixed hang of all threads with
     inaccessible NFS server.  Patch by Nir Soffer.

   - bpo-32101(8): Add *note sys.flags.dev_mode: 1c33. flag

   - bpo-32154(9): The ‘asyncio.windows_utils.socketpair()’ function has
     been removed: use directly *note socket.socketpair(): c16. which is
     available on all platforms since Python 3.5 (before, it wasn’t
     available on Windows).  ‘asyncio.windows_utils.socketpair()’ was
     just an alias to ‘socket.socketpair’ on Python 3.5 and newer.

   - bpo-32089(10): warnings: In development (-X dev) and debug mode
     (pydebug build), use the “default” action for ResourceWarning,
     rather than the “always” action, in the default warnings filters.

   - bpo-32107(11): ‘uuid.getnode()’ now preferentially returns
     universally administered MAC addresses if available, over locally
     administered MAC addresses.  This makes a better guarantee for
     global uniqueness of UUIDs returned from ‘uuid.uuid1()’.  If only
     locally administered MAC addresses are available, the first such
     one found is returned.

   - bpo-23033(12): Wildcard is now supported in hostname when it is one
     and only character in the left most segment of hostname in second
     argument of ‘ssl.match_hostname()’.  Patch by Mandeep Singh.

   - bpo-12239(13): Make ‘msilib.SummaryInformation.GetProperty()’
     return ‘None’ when the value of property is ‘VT_EMPTY’.  Initial
     patch by Mark Mc Mahon.

   - bpo-28334(14): Use *note os.path.expanduser(): a21. to find the
     ‘~/.netrc’ file in *note netrc.netrc: 1a20.  If it does not exist,
     *note FileNotFoundError: 42e. is raised.  Patch by Dimitri
     Merejkowsky.

   - bpo-32121(15): Made ‘tracemalloc.Traceback’ behave more like the
     traceback module, sorting the frames from oldest to most recent.
     ‘Traceback.format()’ now accepts negative 'limit', truncating the
     result to the ‘abs(limit)’ oldest frames.  To get the old
     behaviour, one can use the new 'most_recent_first' argument to
     ‘Traceback.format()’.  (Patch by Jesse Bakker.)

   - bpo-31325(16): Fix wrong usage of *note collections.namedtuple():
     1ca. in the *note RobotFileParser.parse(): 1c34. method.  Initial
     patch by Robin Wellner.

   - bpo-12382(17): ‘msilib.OpenDatabase()’ now raises a better
     exception message when it couldn’t open or create an MSI file.
     Initial patch by William Tisäter.

   - bpo-19610(18): ‘setup()’ now warns about invalid types for some
     fields.  The ‘distutils.dist.Distribution’ class now warns when
     ‘classifiers’, ‘keywords’ and ‘platforms’ fields are not specified
     as a list or a string.

   - bpo-32071(19): Added the ‘-k’ command-line option to ‘python -m
     unittest’ to run only tests that match the given pattern(s).

   - bpo-10049(20): Added 'nullcontext' no-op context manager to
     contextlib.  This provides a simpler and faster alternative to
     ExitStack() when handling optional context managers.

   - bpo-28684(21): The new test.support.skip_unless_bind_unix_socket()
     decorator is used here to skip asyncio tests that fail because the
     platform lacks a functional bind() function for unix domain sockets
     (as it is the case for non root users on the recent Android
     versions that run now SELinux in enforcing mode).

   - bpo-32110(22): ‘codecs.StreamReader.read(n)’ now returns not more
     than 'n' characters/bytes for non-negative 'n'.  This makes it
     compatible with ‘read()’ methods of other file-like objects.

   - bpo-27535(23): The warnings module doesn’t leak memory anymore in
     the hidden warnings registry for the “ignore” action of warnings
     filters.  warn_explicit() function doesn’t add the warning key to
     the registry anymore for the “ignore” action.

   - bpo-32088(24): warnings: When Python is build is debug mode
     (‘Py_DEBUG’), *note DeprecationWarning: 1a5, *note
     PendingDeprecationWarning: 8d1. and *note ImportWarning: 4fd.
     warnings are now displayed by default.

   - bpo-1647489(25): Fixed searching regular expression patterns that
     could match an empty string.  Non-empty string can now be correctly
     found after matching an empty string.

   - bpo-25054(26): Added support of splitting on a pattern that could
     match an empty string.

   - bpo-32072(27): Fixed issues with binary plists: Fixed saving
     bytearrays.  Identical objects will be saved only once.  Equal
     references will be load as identical objects.  Added support for
     saving and loading recursive data structures.

   - bpo-32069(28): Drop legacy SSL transport from asyncio,
     ssl.MemoryBIO is always used anyway.

   - bpo-32066(29): asyncio: Support pathlib.Path in
     create_unix_connection; sock arg should be optional

   - bpo-32046(30): Updates 2to3 to convert from
     operator.isCallable(obj) to callable(obj).  Patch by Donghee Na.

   - bpo-32018(31): inspect.signature should follow PEP 8(32), if the
     parameter has an annotation and a default value.  Patch by Donghee
     Na.

   - bpo-32025(33): Add time.thread_time() and time.thread_time_ns()

   - bpo-32037(34): Integers that fit in a signed 32-bit integer will be
     now pickled with protocol 0 using the INT opcode.  This will
     decrease the size of a pickle, speed up pickling and unpickling,
     and make these integers be unpickled as int instances in Python 2.

   - bpo-32034(35): Make asyncio.IncompleteReadError and
     LimitOverrunError pickleable.

   - bpo-32015(36): Fixed the looping of asyncio in the case of
     reconnection the socket during waiting async read/write from/to the
     socket.

   - bpo-32011(37): Restored support of loading marshal files with the
     TYPE_INT64 code.  These files can be produced in Python 2.7.

   - bpo-28369(38): Enhance add_reader/writer check that socket is not
     used by some transport.  Before, only cases when add_reader/writer
     were called with an int FD were supported.  Now the check is
     implemented correctly for all file-like objects.

   - bpo-31976(39): Fix race condition when flushing a file is slow,
     which can cause a segfault if closing the file from another thread.

   - bpo-31985(40): Formally deprecated aifc.openfp, sunau.openfp, and
     wave.openfp.  Since change 7bc817d5ba917528e8bd07ec461c635291e7b06a
     in 1993, openfp in each of the three modules had been pointing to
     that module’s open function as a matter of backwards compatibility,
     though it had been both untested and undocumented.

   - bpo-21862(41): cProfile command line now accepts ‘-m module_name’
     as an alternative to script path.  Patch by Sanyam Khurana.

   - bpo-31970(42): Reduce performance overhead of asyncio debug mode.

   - bpo-31843(43): 'database' argument of sqlite3.connect() now accepts
     a *note path-like object: 2a0, instead of just a string.

   - bpo-31945(44): Add Configurable 'blocksize' to ‘HTTPConnection’ and
     ‘HTTPSConnection’ for improved upload throughput.  Patch by Nir
     Soffer.

   - bpo-31943(45): Add a ‘cancelled()’ method to *note asyncio.Handle:
     1c35.  Patch by Marat Sharafutdinov.

   - bpo-9678(46): Fixed determining the MAC address in the uuid module:
     Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD,
     NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

   - bpo-30057(47): Fix potential missed signal in signal.signal().

   - bpo-31933(48): Fix Blake2 params leaf_size and node_offset on big
     endian platforms.  Patch by Jack O’Connor.

   - bpo-21423(49): Add an initializer argument to
     {Process,Thread}PoolExecutor

   - bpo-31927(50): Fixed compilation of the socket module on NetBSD 8.
     Fixed assertion failure or reading arbitrary data when parse a
     AF_BLUETOOTH address on NetBSD and DragonFly BSD.

   - bpo-27666(51): Fixed stack corruption in curses.box() and
     curses.ungetmouse() when the size of types chtype or mmask_t is
     less than the size of C long.  curses.box() now accepts characters
     as arguments.  Based on patch by Steve Fink.

   - bpo-31917(52): Add 3 new clock identifiers: *note
     time.CLOCK_BOOTTIME: bac, *note time.CLOCK_PROF: bad. and *note
     time.CLOCK_UPTIME: bae.

   - bpo-31897(53): plistlib now catches more errors when read binary
     plists and raises InvalidFileException instead of unexpected
     exceptions.

   - bpo-25720(54): Fix the method for checking pad state of curses
     WINDOW. Patch by Masayuki Yamamoto.

   - bpo-31893(55): Fixed the layout of the kqueue_event structure on
     OpenBSD and NetBSD. Fixed the comparison of the kqueue_event
     objects.

   - bpo-31891(56): Fixed building the curses module on NetBSD.

   - bpo-31884(57): added required constants to subprocess module for
     setting priority on windows

   - bpo-28281(58): Remove year (1-9999) limits on the
     Calendar.weekday() function.  Patch by Mark Gollahon.

   - bpo-31702(59): crypt.mksalt() now allows to specify the number of
     rounds for SHA-256 and SHA-512 hashing.

   - bpo-30639(60): *note inspect.getfile(): 1c36. no longer computes
     the repr of unknown objects to display in an error message, to
     protect against badly behaved custom reprs.

   - bpo-30768(61): Fix the pthread+semaphore implementation of
     PyThread_acquire_lock_timed() when called with timeout > 0 and
     intr_flag=0: recompute the timeout if sem_timedwait() is
     interrupted by a signal (EINTR). See also the PEP 475(62).

   - bpo-31854(63): Add ‘mmap.ACCESS_DEFAULT’ constant.

   - bpo-31834(64): Use optimized code for BLAKE2 only with SSSE3+.  The
     pure SSE2 implementation is slower than the pure C reference
     implementation.

   - bpo-28292(65): Calendar.itermonthdates() will now consistently
     raise an exception when a date falls outside of the 0001-01-01
     through 9999-12-31 range.  To support applications that cannot
     tolerate such exceptions, the new methods itermonthdays3() and
     itermonthdays4() are added.  The new methods return tuples and are
     not restricted by the range supported by datetime.date.

   - bpo-28564(66): The shutil.rmtree() function has been sped up to
     20–40%.  This was done using the os.scandir() function.

   - bpo-28416(67): Instances of pickle.Pickler subclass with the
     persistent_id() method and pickle.Unpickler subclass with the
     persistent_load() method no longer create reference cycles.

   - bpo-31653(68): Don’t release the GIL if we can acquire a
     multiprocessing semaphore immediately.

   - bpo-28326(69): Fix multiprocessing.Process when stdout and/or
     stderr is closed or None.

   - bpo-20825(70): Add ‘subnet_of’ and ‘superset_of’ containment tests
     to *note ipaddress.IPv6Network: 1ff. and *note
     ipaddress.IPv4Network: 1fe.  Patch by Michel Albert and Cheryl
     Sabella.

   - bpo-31827(71): Remove the os.stat_float_times() function.  It was
     introduced in Python 2.3 for backward compatibility with Python
     2.2, and was deprecated since Python 3.1.

   - bpo-31756(72): Add a ‘subprocess.Popen(text=False)’ keyword
     argument to ‘subprocess’ functions to be more explicit about when
     the library should attempt to decode outputs into text.  Patch by
     Andrew Clegg.

   - bpo-31819(73): Add AbstractEventLoop.sock_recv_into().

   - bpo-31457(74): If nested log adapters are used, the inner
     ‘process()’ methods are no longer omitted.

   - bpo-31457(75): The ‘manager’ property on LoggerAdapter objects is
     now properly settable.

   - bpo-31806(76): Fix timeout rounding in time.sleep(),
     threading.Lock.acquire() and socket.socket.settimeout() to round
     correctly negative timeouts between -1.0 and 0.0.  The functions
     now block waiting for events as expected.  Previously, the call was
     incorrectly non-blocking.  Patch by Pablo Galindo.

   - bpo-31803(77): time.clock() and time.get_clock_info(‘clock’) now
     emit a DeprecationWarning warning.

   - bpo-31800(78): Extended support for parsing UTC offsets.  strptime
     ‘%z’ can now parse the output generated by datetime.isoformat,
     including seconds and microseconds.

   - bpo-28603(79): traceback: Fix a TypeError that occurred during
     printing of exception tracebacks when either the current exception
     or an exception in its context/cause chain is unhashable.  Patch by
     Zane Bitter.

   - bpo-30541(80): Add new function to seal a mock and prevent the
     automatically creation of child mocks.  Patch by Mario Corchero.

   - bpo-31784(81): Implement the PEP 564(82), add new 6 new functions
     with nanosecond resolution to the *note time: ee. module: *note
     clock_gettime_ns(): afa, *note clock_settime_ns(): afb, *note
     monotonic_ns(): afc, *note perf_counter_ns(): afd, *note
     process_time_ns(): afe, *note time_ns(): aff.

   - bpo-30143(83): 2to3 now generates a code that uses abstract
     collection classes from collections.abc rather than collections.

   - bpo-31770(84): Prevent a crash when calling the ‘__init__()’ method
     of a ‘sqlite3.Cursor’ object more than once.  Patch by Oren Milman.

   - bpo-31764(85): Prevent a crash in ‘sqlite3.Cursor.close()’ in case
     the ‘Cursor’ object is uninitialized.  Patch by Oren Milman.

   - bpo-31752(86): Fix possible crash in timedelta constructor called
     with custom integers.

   - bpo-31620(87): an empty asyncio.Queue now doesn’t leak memory when
     queue.get pollers timeout

   - bpo-31690(88): Allow the flags re.ASCII, re.LOCALE, and re.UNICODE
     to be used as group flags for regular expressions.

   - bpo-30349(89): FutureWarning is now emitted if a regular expression
     contains character set constructs that will change semantically in
     the future (nested sets and set operations).

   - bpo-31664(90): Added support for the Blowfish hashing in the crypt
     module.

   - bpo-31632(91): Fix method set_protocol() of class
     _SSLProtocolTransport in asyncio module.  This method was
     previously modifying a wrong reference to the protocol.

   - bpo-15037(92): Added a workaround for getkey() in curses for
     ncurses 5.7 and earlier.

   - bpo-31307(93): Allow use of bytes objects for arguments to *note
     configparser.ConfigParser.read(): 14b7.  Patch by Vincent Michel.

   - bpo-31334(94): Fix ‘poll.poll([timeout])’ in the ‘select’ module
     for arbitrary negative timeouts on all OSes where it can only be a
     non-negative integer or -1.  Patch by Riccardo Coccioli.

   - bpo-31310(95): multiprocessing’s semaphore tracker should be
     launched again if crashed.

   - bpo-31308(96): Make multiprocessing’s forkserver process immune to
     Ctrl-C and other user interruptions.  If it crashes, restart it
     when necessary.

   - bpo-31245(97): Added support for AF_UNIX socket in asyncio
     ‘create_datagram_endpoint’.

   - bpo-30553(98): Add HTTP/2 status code 421 (Misdirected Request) to
     *note http.HTTPStatus: 909.  Patch by Vitor Pereira.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32214

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27240

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30788

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31831

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32182

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32186

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32101

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32154

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32089

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32107

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23033

   (13) https://bugs.python.org/issue?@action=redirect&bpo=12239

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28334

   (15) https://bugs.python.org/issue?@action=redirect&bpo=32121

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31325

   (17) https://bugs.python.org/issue?@action=redirect&bpo=12382

   (18) https://bugs.python.org/issue?@action=redirect&bpo=19610

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32071

   (20) https://bugs.python.org/issue?@action=redirect&bpo=10049

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28684

   (22) https://bugs.python.org/issue?@action=redirect&bpo=32110

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27535

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32088

   (25) https://bugs.python.org/issue?@action=redirect&bpo=1647489

   (26) https://bugs.python.org/issue?@action=redirect&bpo=25054

   (27) https://bugs.python.org/issue?@action=redirect&bpo=32072

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32069

   (29) https://bugs.python.org/issue?@action=redirect&bpo=32066

   (30) https://bugs.python.org/issue?@action=redirect&bpo=32046

   (31) https://bugs.python.org/issue?@action=redirect&bpo=32018

   (32) https://peps.python.org/pep-0008/

   (33) https://bugs.python.org/issue?@action=redirect&bpo=32025

   (34) https://bugs.python.org/issue?@action=redirect&bpo=32037

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32034

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32015

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32011

   (38) https://bugs.python.org/issue?@action=redirect&bpo=28369

   (39) https://bugs.python.org/issue?@action=redirect&bpo=31976

   (40) https://bugs.python.org/issue?@action=redirect&bpo=31985

   (41) https://bugs.python.org/issue?@action=redirect&bpo=21862

   (42) https://bugs.python.org/issue?@action=redirect&bpo=31970

   (43) https://bugs.python.org/issue?@action=redirect&bpo=31843

   (44) https://bugs.python.org/issue?@action=redirect&bpo=31945

   (45) https://bugs.python.org/issue?@action=redirect&bpo=31943

   (46) https://bugs.python.org/issue?@action=redirect&bpo=9678

   (47) https://bugs.python.org/issue?@action=redirect&bpo=30057

   (48) https://bugs.python.org/issue?@action=redirect&bpo=31933

   (49) https://bugs.python.org/issue?@action=redirect&bpo=21423

   (50) https://bugs.python.org/issue?@action=redirect&bpo=31927

   (51) https://bugs.python.org/issue?@action=redirect&bpo=27666

   (52) https://bugs.python.org/issue?@action=redirect&bpo=31917

   (53) https://bugs.python.org/issue?@action=redirect&bpo=31897

   (54) https://bugs.python.org/issue?@action=redirect&bpo=25720

   (55) https://bugs.python.org/issue?@action=redirect&bpo=31893

   (56) https://bugs.python.org/issue?@action=redirect&bpo=31891

   (57) https://bugs.python.org/issue?@action=redirect&bpo=31884

   (58) https://bugs.python.org/issue?@action=redirect&bpo=28281

   (59) https://bugs.python.org/issue?@action=redirect&bpo=31702

   (60) https://bugs.python.org/issue?@action=redirect&bpo=30639

   (61) https://bugs.python.org/issue?@action=redirect&bpo=30768

   (62) https://peps.python.org/pep-0475/

   (63) https://bugs.python.org/issue?@action=redirect&bpo=31854

   (64) https://bugs.python.org/issue?@action=redirect&bpo=31834

   (65) https://bugs.python.org/issue?@action=redirect&bpo=28292

   (66) https://bugs.python.org/issue?@action=redirect&bpo=28564

   (67) https://bugs.python.org/issue?@action=redirect&bpo=28416

   (68) https://bugs.python.org/issue?@action=redirect&bpo=31653

   (69) https://bugs.python.org/issue?@action=redirect&bpo=28326

   (70) https://bugs.python.org/issue?@action=redirect&bpo=20825

   (71) https://bugs.python.org/issue?@action=redirect&bpo=31827

   (72) https://bugs.python.org/issue?@action=redirect&bpo=31756

   (73) https://bugs.python.org/issue?@action=redirect&bpo=31819

   (74) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (75) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (76) https://bugs.python.org/issue?@action=redirect&bpo=31806

   (77) https://bugs.python.org/issue?@action=redirect&bpo=31803

   (78) https://bugs.python.org/issue?@action=redirect&bpo=31800

   (79) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (80) https://bugs.python.org/issue?@action=redirect&bpo=30541

   (81) https://bugs.python.org/issue?@action=redirect&bpo=31784

   (82) https://peps.python.org/pep-0564/

   (83) https://bugs.python.org/issue?@action=redirect&bpo=30143

   (84) https://bugs.python.org/issue?@action=redirect&bpo=31770

   (85) https://bugs.python.org/issue?@action=redirect&bpo=31764

   (86) https://bugs.python.org/issue?@action=redirect&bpo=31752

   (87) https://bugs.python.org/issue?@action=redirect&bpo=31620

   (88) https://bugs.python.org/issue?@action=redirect&bpo=31690

   (89) https://bugs.python.org/issue?@action=redirect&bpo=30349

   (90) https://bugs.python.org/issue?@action=redirect&bpo=31664

   (91) https://bugs.python.org/issue?@action=redirect&bpo=31632

   (92) https://bugs.python.org/issue?@action=redirect&bpo=15037

   (93) https://bugs.python.org/issue?@action=redirect&bpo=31307

   (94) https://bugs.python.org/issue?@action=redirect&bpo=31334

   (95) https://bugs.python.org/issue?@action=redirect&bpo=31310

   (96) https://bugs.python.org/issue?@action=redirect&bpo=31308

   (97) https://bugs.python.org/issue?@action=redirect&bpo=31245

   (98) https://bugs.python.org/issue?@action=redirect&bpo=30553


File: python.info,  Node: Documentation<62>,  Next: Tests<63>,  Prev: Library<147>,  Up: Python 3 7 0 alpha 3

1.23.72.3 Documentation
.......................

   - bpo-32105(1): Added asyncio.BaseEventLoop.connect_accepted_socket
     versionadded marker.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32105


File: python.info,  Node: Tests<63>,  Next: Build<67>,  Prev: Documentation<62>,  Up: Python 3 7 0 alpha 3

1.23.72.4 Tests
...............

   - bpo-31380(1): Skip test_httpservers test_undecodable_file on macOS:
     fails on APFS.

   - bpo-31705(2): Skip test_socket.test_sha256() on Linux kernel older
     than 4.5.  The test fails with ENOKEY on kernel 3.10 (on ppc64le).
     A fix was merged into the kernel 4.5.

   - bpo-32138(3): Skip on Android test_faulthandler tests that raise
     SIGSEGV and remove the test.support.requires_android_level
     decorator.

   - bpo-32136(4): The runtime embedding tests have been split out from
     ‘Lib/test/test_capi.py’ into a new ‘Lib/test/test_embed.py’ file.

   - bpo-28668(5): test.support.requires_multiprocessing_queue is
     removed.  Skip tests with
     test.support.import_module(‘multiprocessing.synchronize’) instead
     when the semaphore implementation is broken or missing.

   - bpo-32126(6): Skip test_get_event_loop_new_process in
     test.test_asyncio.test_events when sem_open() is not functional.

   - bpo-31174(7): Fix test_tools.test_unparse: DirectoryTestCase now
     stores the names sample to always test the same files.  It prevents
     false alarms when hunting reference leaks.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31380

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31705

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32138

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32136

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28668

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32126

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31174


File: python.info,  Node: Build<67>,  Next: Windows<60>,  Prev: Tests<63>,  Up: Python 3 7 0 alpha 3

1.23.72.5 Build
...............

   - bpo-28538(1): Revert the previous changes, the if_nameindex
     structure is defined by Unified Headers.

   - bpo-28762(2): Revert the last commit, the F_LOCK macro is defined
     by Android Unified Headers.

   - bpo-29040(3): Support building Android with Unified Headers.  The
     first NDK release to support Unified Headers is android-ndk-r14.

   - bpo-32059(4): ‘detect_modules()’ in ‘setup.py’ now also searches
     the sysroot paths when cross-compiling.

   - bpo-31957(5): Fixes Windows SDK version detection when building for
     Windows.

   - bpo-31609(6): Fixes quotes in PCbuild/clean.bat

   - bpo-31934(7): Abort the build when building out of a not clean
     source tree.

   - bpo-31926(8): Fixed Argument Clinic sometimes causing compilation
     errors when there was more than one function and/or method in a .c
     file with the same name.

   - bpo-28791(9): Update Windows builds to use SQLite 3.21.0.

   - bpo-28791(10): Update OS X installer to use SQLite 3.21.0.

   - bpo-28643(11): Record profile-opt build progress with stamp files.

   - bpo-31866(12): Finish removing support for AtheOS.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28538

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28762

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29040

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32059

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31957

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31609

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31934

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31926

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28791

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28791

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28643

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31866


File: python.info,  Node: Windows<60>,  Next: macOS<48>,  Prev: Build<67>,  Up: Python 3 7 0 alpha 3

1.23.72.6 Windows
.................

   - bpo-1102(1): Return ‘None’ when ‘View.Fetch()’ returns
     ‘ERROR_NO_MORE_ITEMS’ instead of raising ‘MSIError’.  Initial patch
     by Anthony Tuininga.

   - bpo-31944(2): Fixes Modify button in Apps and Features dialog.

   - bpo-20486(3): Implement the ‘Database.Close()’ method to help
     closing MSI database objects.

   - bpo-31857(4): Make the behavior of USE_STACKCHECK deterministic in
     a multi-threaded environment.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1102

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31944

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20486

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31857


File: python.info,  Node: macOS<48>,  Next: IDLE<47>,  Prev: Windows<60>,  Up: Python 3 7 0 alpha 3

1.23.72.7 macOS
...............

   - bpo-31392(1): Update macOS installer to use OpenSSL 1.0.2m

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31392


File: python.info,  Node: IDLE<47>,  Next: Tools/Demos<35>,  Prev: macOS<48>,  Up: Python 3 7 0 alpha 3

1.23.72.8 IDLE
..............

   - bpo-32207(1): Improve tk event exception tracebacks in IDLE. When
     tk event handling is driven by IDLE’s run loop, a confusing and
     distracting queue.EMPTY traceback context is no longer added to tk
     event exception tracebacks.  The traceback is now the same as when
     event handling is driven by user code.  Patch based on a suggestion
     by Serhiy Storchaka.

   - bpo-32164(2): Delete unused file idlelib/tabbedpages.py.  Use of
     TabbedPageSet in configdialog was replaced by ttk.Notebook.

   - bpo-32100(3): IDLE: Fix old and new bugs in pathbrowser; improve
     tests.  Patch mostly by Cheryl Sabella.

   - bpo-31858(4): IDLE – Restrict shell prompt manipulation to the
     shell.  Editor and output windows only see an empty last prompt
     line.  This simplifies the code and fixes a minor bug when newline
     is inserted.  Sys.ps1, if present, is read on Shell start-up, but
     is not set or changed.

   - bpo-31860(5): The font sample in the IDLE configuration dialog is
     now editable.  Changes persist while IDLE remains open

   - bpo-31836(6): Test_code_module now passes if run after test_idle,
     which sets ps1.  The code module uses sys.ps1 if present or sets it
     to ‘>>> ‘ if not.  Test_code_module now properly tests both
     behaviors.  Ditto for ps2.

   - bpo-28603(7): Fix a TypeError that caused a shell restart when
     printing a traceback that includes an exception that is unhashable.
     Patch by Zane Bitter.

   - bpo-13802(8): Use non-Latin characters in the IDLE’s Font settings
     sample.  Even if one selects a font that defines a limited subset
     of the unicode Basic Multilingual Plane, tcl/tk will use other
     fonts that define a character.  The expanded example give users of
     non-Latin characters a better idea of what they might see in IDLE’s
     shell and editors.  To make room for the expanded sample, frames on
     the Font tab are re-arranged.  The Font/Tabs help explains a bit
     about the additions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32207

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32164

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32100

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31858

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31860

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31836

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13802


File: python.info,  Node: Tools/Demos<35>,  Next: C API<60>,  Prev: IDLE<47>,  Up: Python 3 7 0 alpha 3

1.23.72.9 Tools/Demos
.....................

   - bpo-32159(1): Remove CVS and Subversion tools: remove svneol.py and
     treesync.py scripts.  CPython migrated from CVS to Subversion, to
     Mercurial, and then to Git.  CVS and Subversion are no longer used
     to develop CPython.

   - bpo-30722(2): Make redemo work with Python 3.6 and newer versions.
     Also, remove the ‘LOCALE’ option since it doesn’t work with string
     patterns in Python 3.  Patch by Christoph Sarnowski.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32159

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30722


File: python.info,  Node: C API<60>,  Prev: Tools/Demos<35>,  Up: Python 3 7 0 alpha 3

1.23.72.10 C API
................

   - bpo-20891(1): Fix PyGILState_Ensure().  When PyGILState_Ensure() is
     called in a non-Python thread before PyEval_InitThreads(), only
     call PyEval_InitThreads() after calling PyThreadState_New() to fix
     a crash.

   - bpo-32125(2): The ‘Py_UseClassExceptionsFlag’ flag has been
     removed.  It was deprecated and wasn’t used anymore since Python
     2.0.

   - bpo-25612(3): Move the current exception state from the frame
     object to the co-routine.  This simplifies the interpreter and
     fixes a couple of obscure bugs caused by having swap exception
     state when entering or exiting a generator.

   - bpo-23699(4): Add Py_RETURN_RICHCOMPARE macro to reduce boilerplate
     code in rich comparison functions.

   - bpo-30697(5): The ‘PyExc_RecursionErrorInst’ singleton is removed
     and ‘PyErr_NormalizeException()’ does not use it anymore.  This
     singleton is persistent and its members being never cleared may
     cause a segfault during finalization of the interpreter.  See also
     bpo-22898(6).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20891

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32125

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25612

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23699

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30697

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22898


File: python.info,  Node: Python 3 7 0 alpha 2,  Next: Python 3 7 0 alpha 1,  Prev: Python 3 7 0 alpha 3,  Up: Changelog

1.23.73 Python 3.7.0 alpha 2
----------------------------

'Release date: 2017-10-16'

* Menu:

* Core and Builtins: Core and Builtins<145>.
* Library: Library<148>.
* Documentation: Documentation<63>.
* Build: Build<68>.
* IDLE: IDLE<48>.
* C API: C API<61>.


File: python.info,  Node: Core and Builtins<145>,  Next: Library<148>,  Up: Python 3 7 0 alpha 2

1.23.73.1 Core and Builtins
...........................

   - bpo-31558(1): ‘gc.freeze()’ is a new API that allows for moving all
     objects currently tracked by the garbage collector to a permanent
     generation, effectively removing them from future collection
     events.  This can be used to protect those objects from having
     their PyGC_Head mutated.  In effect, this enables great
     copy-on-write stability at fork().

   - bpo-31642(2): Restored blocking “from package import module” by
     setting sys.modules[“package.module”] to None.

   - bpo-31708(3): Allow use of asynchronous generator expressions in
     synchronous functions.

   - bpo-31709(4): Drop support of asynchronous __aiter__.

   - bpo-30404(5): The -u option now makes the stdout and stderr streams
     unbuffered rather than line-buffered.

   - bpo-31619(6): Fixed a ValueError when convert a string with large
     number of underscores to integer with binary base.

   - bpo-31602(7): Fix an assertion failure in
     ‘zipimporter.get_source()’ in case of a bad ‘zlib.decompress()’.
     Patch by Oren Milman.

   - bpo-31592(8): Fixed an assertion failure in Python parser in case
     of a bad ‘unicodedata.normalize()’.  Patch by Oren Milman.

   - bpo-31588(9): Raise a ‘TypeError’ with a helpful error message when
     class creation fails due to a metaclass with a bad ‘__prepare__()’
     method.  Patch by Oren Milman.

   - bpo-31574(10): Importlib was instrumented with two dtrace probes to
     profile import timing.

   - bpo-31566(11): Fix an assertion failure in ‘_warnings.warn()’ in
     case of a bad ‘__name__’ global.  Patch by Oren Milman.

   - bpo-31506(12): Improved the error message logic for
     ‘object.__new__’ and ‘object.__init__’.

   - bpo-31505(13): Fix an assertion failure in ‘json’, in case
     ‘_json.make_encoder()’ received a bad ‘encoder()’ argument.  Patch
     by Oren Milman.

   - bpo-31492(14): Fix assertion failures in case of failing to import
     from a module with a bad ‘__name__’ attribute, and in case of
     failing to access an attribute of such a module.  Patch by Oren
     Milman.

   - bpo-31478(15): Fix an assertion failure in ‘_random.Random.seed()’
     in case the argument has a bad ‘__abs__()’ method.  Patch by Oren
     Milman.

   - bpo-31336(16): Speed up class creation by 10-20% by reducing the
     overhead in the necessary special method lookups.  Patch by Stefan
     Behnel.

   - bpo-31415(17): Add ‘-X importtime’ option to show how long each
     import takes.  It can be used to optimize application’s startup
     time.  Support the *note PYTHONPROFILEIMPORTTIME: b0e. as an
     equivalent way to enable this.

   - bpo-31410(18): Optimized calling wrapper and classmethod
     descriptors.

   - bpo-31353(19): PEP 553(20) - Add a new built-in called
     ‘breakpoint()’ which calls ‘sys.breakpointhook()’.  By default this
     imports ‘pdb’ and calls ‘pdb.set_trace()’, but users may override
     ‘sys.breakpointhook()’ to call whatever debugger they want.  The
     original value of the hook is saved in ‘sys.__breakpointhook__’.

   - bpo-17852(21): Maintain a list of open buffered files, flush them
     before exiting the interpreter.  Based on a patch from Armin Rigo.

   - bpo-31315(22): Fix an assertion failure in imp.create_dynamic(),
     when spec.name is not a string.  Patch by Oren Milman.

   - bpo-31311(23): Fix a crash in the ‘__setstate__()’ method of
     ‘ctypes._CData’, in case of a bad ‘__dict__’.  Patch by Oren
     Milman.

   - bpo-31293(24): Fix crashes in true division and multiplication of a
     timedelta object by a float with a bad as_integer_ratio() method.
     Patch by Oren Milman.

   - bpo-31285(25): Fix an assertion failure in
     ‘warnings.warn_explicit’, when the return value of the received
     loader’s ‘get_source()’ has a bad ‘splitlines()’ method.  Patch by
     Oren Milman.

   - bpo-30406(26): Make ‘async’ and ‘await’ proper keywords, as
     specified in PEP 492(27).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31558

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31642

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31708

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31709

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30404

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31619

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31602

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31592

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31588

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31574

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31566

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31506

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31505

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31492

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31478

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31336

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31415

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31410

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31353

   (20) https://peps.python.org/pep-0553/

   (21) https://bugs.python.org/issue?@action=redirect&bpo=17852

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31315

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31311

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31293

   (25) https://bugs.python.org/issue?@action=redirect&bpo=31285

   (26) https://bugs.python.org/issue?@action=redirect&bpo=30406

   (27) https://peps.python.org/pep-0492/


File: python.info,  Node: Library<148>,  Next: Documentation<63>,  Prev: Core and Builtins<145>,  Up: Python 3 7 0 alpha 2

1.23.73.2 Library
.................

   - bpo-30058(1): Fixed buffer overflow in select.kqueue.control().

   - bpo-31672(2): ‘idpattern’ in ‘string.Template’ matched some
     non-ASCII characters.  Now it uses ‘-i’ regular expression local
     flag to avoid non-ASCII characters.

   - bpo-31701(3): On Windows, faulthandler.enable() now ignores MSC and
     COM exceptions.

   - bpo-31728(4): Prevent crashes in ‘_elementtree’ due to unsafe
     cleanup of ‘Element.text’ and ‘Element.tail’.  Patch by Oren
     Milman.

   - bpo-31671(5): Now ‘re.compile()’ converts passed RegexFlag to
     normal int object before compiling.  bm_regex_compile benchmark
     shows 14% performance improvements.

   - bpo-30397(6): The types of compiled regular objects and match
     objects are now exposed as ‘re.Pattern’ and ‘re.Match’.  This adds
     information in pydoc output for the ‘re’ module.

   - bpo-31675(7): Fixed memory leaks in Tkinter’s methods splitlist()
     and split() when pass a string larger than 2 GiB.

   - bpo-31673(8): Fixed typo in the name of Tkinter’s method
     adderrorinfo().

   - bpo-31648(9): Improvements to path predicates in ElementTree: Allow
     whitespace around predicate parts, i.e.  “[a = ‘text’]” instead of
     requiring the less readable “[a=’text’]”.  Add support for text
     comparison of the current node, like “[.=’text’]”.  Patch by Stefan
     Behnel.

   - bpo-30806(10): Fix the string representation of a netrc object.

   - bpo-31638(11): Add optional argument ‘compressed’ to
     ‘zipapp.create_archive’, and add option ‘--compress’ to the command
     line interface of ‘zipapp’.

   - bpo-25351(12): Avoid venv activate failures with undefined
     variables

   - bpo-20519(13): Avoid ctypes use (if possible) and improve import
     time for uuid.

   - bpo-28293(14): The regular expression cache is no longer completely
     dumped when it is full.

   - bpo-31596(15): Added pthread_getcpuclockid() to the time module

   - bpo-27494(16): Make 2to3 accept a trailing comma in generator
     expressions.  For example, ‘set(x for x in [],)’ is now allowed.

   - bpo-30347(17): Stop crashes when concurrently iterate over
     itertools.groupby() iterators.

   - bpo-30346(18): An iterator produced by itertools.groupby() iterator
     now becomes exhausted after advancing the groupby iterator.

   - bpo-31556(19): Cancel asyncio.wait_for future faster if timeout <=
     0

   - bpo-31540(20): Allow passing a context object in *note
     concurrent.futures.ProcessPoolExecutor: 8f7. constructor.  Also,
     free job resources in ‘concurrent.futures.ProcessPoolExecutor’
     earlier to improve memory usage when a worker waits for new jobs.

   - bpo-31516(21): ‘threading.current_thread()’ should not return a
     dummy thread at shutdown.

   - bpo-31525(22): In the sqlite module, require the sqlite3_prepare_v2
     API. Thus, the sqlite module now requires sqlite version at least
     3.3.9.

   - bpo-26510(23): argparse subparsers are now required by default.
     This matches behaviour in Python 2.  For optional subparsers, use
     the new parameter ‘add_subparsers(required=False)’.  Patch by
     Anthony Sottile.  (As of 3.7.0rc1, the default was changed to not
     required as had been the case since Python 3.3.)

   - bpo-27541(24): Reprs of subclasses of some collection and iterator
     classes (‘bytearray’, ‘array.array’, ‘collections.deque’,
     ‘collections.defaultdict’, ‘itertools.count’, ‘itertools.repeat’)
     now contain actual type name instead of hardcoded names of the base
     class.

   - bpo-31351(25): python -m ensurepip now exits with non-zero exit
     code if pip bootstrapping has failed.

   - bpo-31389(26): ‘pdb.set_trace()’ now takes an optional keyword-only
     argument ‘header’.  If given, this is printed to the console just
     before debugging begins.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30058

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31672

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31701

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31728

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31671

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30397

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31675

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31673

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31648

   (10) https://bugs.python.org/issue?@action=redirect&bpo=30806

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31638

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25351

   (13) https://bugs.python.org/issue?@action=redirect&bpo=20519

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28293

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31596

   (16) https://bugs.python.org/issue?@action=redirect&bpo=27494

   (17) https://bugs.python.org/issue?@action=redirect&bpo=30347

   (18) https://bugs.python.org/issue?@action=redirect&bpo=30346

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31556

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31540

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31516

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31525

   (23) https://bugs.python.org/issue?@action=redirect&bpo=26510

   (24) https://bugs.python.org/issue?@action=redirect&bpo=27541

   (25) https://bugs.python.org/issue?@action=redirect&bpo=31351

   (26) https://bugs.python.org/issue?@action=redirect&bpo=31389


File: python.info,  Node: Documentation<63>,  Next: Build<68>,  Prev: Library<148>,  Up: Python 3 7 0 alpha 2

1.23.73.3 Documentation
.......................

   - bpo-31537(1): Fix incorrect usage of ‘get_history_length’ in
     readline documentation example code.  Patch by Brad Smith.

   - bpo-30085(2): The operator functions without double underscores are
     preferred for clarity.  The one with underscores are only kept for
     back-compatibility.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31537

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30085


File: python.info,  Node: Build<68>,  Next: IDLE<48>,  Prev: Documentation<63>,  Up: Python 3 7 0 alpha 2

1.23.73.4 Build
...............

   - bpo-31696(1): Improve compiler version information in *note
     sys.version: 178. when Python is built with Clang.

   - bpo-31625(2): Stop using ranlib on static libraries.  Instead, we
     assume ar supports the ‘s’ flag.

   - bpo-31624(3): Remove support for BSD/OS.

   - bpo-22140(4): Prevent double substitution of prefix in
     python-config.sh.

   - bpo-31569(5): Correct PCBuild/ case to PCbuild/ in build scripts
     and documentation.

   - bpo-31536(6): Avoid wholesale rebuild after ‘make regen-all’ if
     nothing changed.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31696

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31625

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31624

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22140

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31569

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31536


File: python.info,  Node: IDLE<48>,  Next: C API<61>,  Prev: Build<68>,  Up: Python 3 7 0 alpha 2

1.23.73.5 IDLE
..............

   - bpo-31460(1): Simplify the API of IDLE’s Module Browser.  Passing a
     widget instead of an flist with a root widget opens the option of
     creating a browser frame that is only part of a window.  Passing a
     full file name instead of pieces assumed to come from a .py file
     opens the possibility of browsing python files that do not end in
     .py.

   - bpo-31649(2): IDLE - Make _htest, _utest parameters keyword only.

   - bpo-31559(3): Remove test order dependence in
     idle_test.test_browser.

   - bpo-31459(4): Rename IDLE’s module browser from Class Browser to
     Module Browser.  The original module-level class and method browser
     became a module browser, with the addition of module-level
     functions, years ago.  Nested classes and functions were added
     yesterday.  For back-compatibility, the virtual event
     <<open-class-browser>>, which appears on the Keys tab of the
     Settings dialog, is not changed.  Patch by Cheryl Sabella.

   - bpo-31500(5): Default fonts now are scaled on HiDPI displays.

   - bpo-1612262(6): IDLE module browser now shows nested classes and
     functions.  Original patches for code and tests by Guilherme Polo
     and Cheryl Sabella, respectively.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31460

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31559

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31459

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31500

   (6) https://bugs.python.org/issue?@action=redirect&bpo=1612262


File: python.info,  Node: C API<61>,  Prev: IDLE<48>,  Up: Python 3 7 0 alpha 2

1.23.73.6 C API
...............

   - bpo-28280(1): Make ‘PyMapping_Keys()’, ‘PyMapping_Values()’ and
     ‘PyMapping_Items()’ always return a ‘list’ (rather than a ‘list’ or
     a ‘tuple’).  Patch by Oren Milman.

   - bpo-31532(2): Fix memory corruption due to allocator mix in
     getpath.c between Py_GetPath() and Py_SetPath()

   - bpo-25658(3): Implement PEP 539(4) for Thread Specific Storage
     (TSS) API: it is a new Thread Local Storage (TLS) API to CPython
     which would supersede use of the existing TLS API within the
     CPython interpreter, while deprecating the existing API. PEP
     written by Erik M. Bray, patch by Masayuki Yamamoto.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28280

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31532

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25658

   (4) https://peps.python.org/pep-0539/


File: python.info,  Node: Python 3 7 0 alpha 1,  Next: Python 3 6 6 final,  Prev: Python 3 7 0 alpha 2,  Up: Changelog

1.23.74 Python 3.7.0 alpha 1
----------------------------

'Release date: 2017-09-19'

* Menu:

* Security: Security<46>.
* Core and Builtins: Core and Builtins<146>.
* Library: Library<149>.
* Documentation: Documentation<64>.
* Tests: Tests<64>.
* Build: Build<69>.
* Windows: Windows<61>.
* IDLE: IDLE<49>.
* Tools/Demos: Tools/Demos<36>.
* C API: C API<62>.


File: python.info,  Node: Security<46>,  Next: Core and Builtins<146>,  Up: Python 3 7 0 alpha 1

1.23.74.1 Security
..................

   - bpo-29781(1): SSLObject.version() now correctly returns None when
     handshake over BIO has not been performed yet.

   - bpo-29505(2): Add fuzz tests for float(str), int(str),
     unicode(str); for oss-fuzz.

   - bpo-30947(3): Upgrade libexpat embedded copy from version 2.2.1 to
     2.2.3 to get security fixes.

   - bpo-30730(4): Prevent environment variables injection in subprocess
     on Windows.  Prevent passing other environment variables and
     command arguments.

   - bpo-30694(5): Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes
     of multiple security vulnerabilities including: CVE 2017-9233(6)
     (External entity infinite loop DoS), CVE 2016-9063(7) (Integer
     overflow, re-fix), CVE 2016-0718(8) (Fix regression bugs from
     2.2.0’s fix to CVE 2016-0718(9)) and CVE 2012-0876(10) (Counter
     hash flooding with SipHash).  Note: the CVE 2016-5300(11) (Use
     os-specific entropy sources like getrandom) doesn’t impact Python,
     since Python already gets entropy from the OS to set the expat
     secret using ‘XML_SetHashSalt()’.

   - bpo-30500(12): Fix urllib.parse.splithost() to correctly parse
     fragments.  For example, ‘splithost('//127.0.0.1#@evil.com/')’ now
     correctly returns the ‘127.0.0.1’ host, instead of treating
     ‘@evil.com’ as the host in an authentication (‘login@host’).

   - bpo-29591(13): Update expat copy from 2.1.1 to 2.2.0 to get fixes
     of CVE 2016-0718(14) and CVE 2016-4472(15).  See
     ‘https://sourceforge.net/p/expat/bugs/537/’ for more information.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29781

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29505

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30947

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30730

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30694

   (6) https://www.cve.org/CVERecord?id=CVE-2017-9233

   (7) https://www.cve.org/CVERecord?id=CVE-2016-9063

   (8) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (9) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (10) https://www.cve.org/CVERecord?id=CVE-2012-0876

   (11) https://www.cve.org/CVERecord?id=CVE-2016-5300

   (12) https://bugs.python.org/issue?@action=redirect&bpo=30500

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29591

   (14) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (15) https://www.cve.org/CVERecord?id=CVE-2016-4472


File: python.info,  Node: Core and Builtins<146>,  Next: Library<149>,  Prev: Security<46>,  Up: Python 3 7 0 alpha 1

1.23.74.2 Core and Builtins
...........................

   - bpo-31490(1): Fix an assertion failure in ‘ctypes’ class
     definition, in case the class has an attribute whose name is
     specified in ‘_anonymous_’ but not in ‘_fields_’.  Patch by Oren
     Milman.

   - bpo-31471(2): Fix an assertion failure in ‘subprocess.Popen()’ on
     Windows, in case the env argument has a bad ‘keys()’ method.  Patch
     by Oren Milman.

   - bpo-31418(3): Fix an assertion failure in ‘PyErr_WriteUnraisable()’
     in case of an exception with a bad ‘__module__’ attribute.  Patch
     by Oren Milman.

   - bpo-31416(4): Fix assertion failures in case of a bad
     warnings.filters or warnings.defaultaction.  Patch by Oren Milman.

   - bpo-28411(5): Change direct usage of PyInterpreterState.modules to
     PyImport_GetModuleDict().  Also introduce more uniformity in other
     code that deals with sys.modules.  This helps reduce complications
     when working on sys.modules.

   - bpo-28411(6): Switch to the abstract API when dealing with
     ‘PyInterpreterState.modules’.  This allows later support for all
     dict subclasses and other Mapping implementations.  Also add a
     ‘PyImport_GetModule()’ function to reduce a bunch of duplicated
     code.

   - bpo-31411(7): Raise a TypeError instead of SystemError in case
     warnings.onceregistry is not a dictionary.  Patch by Oren Milman.

   - bpo-31344(8): For finer control of tracing behaviour when testing
     the interpreter, two new frame attributes have been added to
     control the emission of particular trace events: ‘f_trace_lines’
     (‘True’ by default) to turn off per-line trace events; and
     ‘f_trace_opcodes’ (‘False’ by default) to turn on per-opcode trace
     events.

   - bpo-31373(9): Fix several possible instances of undefined behavior
     due to floating-point demotions.

   - bpo-30465(10): Location information (‘lineno’ and ‘col_offset’) in
     f-strings is now (mostly) correct.  This fixes tools like flake8
     from showing warnings on the wrong line (typically the first line
     of the file).

   - bpo-30860(11): Consolidate CPython’s global runtime state under a
     single struct.  This improves discoverability of the runtime state.

   - bpo-31347(12): Fix possible undefined behavior in
     _PyObject_FastCall_Prepend.

   - bpo-31343(13): Include sys/sysmacros.h for major(), minor(), and
     makedev().  GNU C libray plans to remove the functions from
     sys/types.h.

   - bpo-31291(14): Fix an assertion failure in
     ‘zipimport.zipimporter.get_data’ on Windows, when the return value
     of ‘pathname.replace('/','\\')’ isn’t a string.  Patch by Oren
     Milman.

   - bpo-31271(15): Fix an assertion failure in the ‘write()’ method of
     ‘io.TextIOWrapper’, when the encoder doesn’t return a bytes object.
     Patch by Oren Milman.

   - bpo-31243(16): Fix a crash in some methods of ‘io.TextIOWrapper’,
     when the decoder’s state is invalid.  Patch by Oren Milman.

   - bpo-30721(17): ‘print’ now shows correct usage hint for using
     Python 2 redirection syntax.  Patch by Sanyam Khurana.

   - bpo-31070(18): Fix a race condition in importlib
     _get_module_lock().

   - bpo-30747(19): Add a non-dummy implementation of _Py_atomic_store
     and _Py_atomic_load on MSVC.

   - bpo-31095(20): Fix potential crash during GC caused by ‘tp_dealloc’
     which doesn’t call ‘PyObject_GC_UnTrack()’.

   - bpo-31071(21): Avoid masking original TypeError in call with *
     unpacking when other arguments are passed.

   - bpo-30978(22): str.format_map() now passes key lookup exceptions
     through.  Previously any exception was replaced with a KeyError
     exception.

   - bpo-30808(23): Use _Py_atomic API for concurrency-sensitive signal
     state.

   - bpo-30876(24): Relative import from unloaded package now reimports
     the package instead of failing with SystemError.  Relative import
     from non-package now fails with ImportError rather than
     SystemError.

   - bpo-30703(25): Improve signal delivery.  Avoid using
     Py_AddPendingCall from signal handler, to avoid calling
     signal-unsafe functions.  The tests I’m adding here fail without
     the rest of the patch, on Linux and OS X. This means our signal
     delivery logic had defects (some signals could be lost).

   - bpo-30765(26): Avoid blocking in pthread_mutex_lock() when
     PyThread_acquire_lock() is asked not to block.

   - bpo-31161(27): Make sure the ‘Missing parentheses’ syntax error
     message is only applied to SyntaxError, not to subclasses.  Patch
     by Martijn Pieters.

   - bpo-30814(28): Fixed a race condition when import a submodule from
     a package.

   - bpo-30736(29): The internal unicodedata database has been upgraded
     to Unicode 10.0.

   - bpo-30604(30): Move co_extra_freefuncs from per-thread to
     per-interpreter to avoid crashes.

   - bpo-30597(31): ‘print’ now shows expected input in custom error
     message when used as a Python 2 statement.  Patch by Sanyam
     Khurana.

   - bpo-30682(32): Removed a too-strict assertion that failed for
     certain f-strings, such as eval(“f’\n’”) and eval(“f’\r’”).

   - bpo-30501(33): The compiler now produces more optimal code for
     complex condition expressions in the “if”, “while” and “assert”
     statement, the “if” expression, and generator expressions and
     comprehensions.

   - bpo-28180(34): Implement PEP 538(35) (legacy C locale coercion).
     This means that when a suitable coercion target locale is
     available, both the core interpreter and locale-aware C extensions
     will assume the use of UTF-8 as the default text encoding, rather
     than ASCII.

   - bpo-30486(36): Allows setting cell values for __closure__.  Patch
     by Lisa Roach.

   - bpo-30537(37): itertools.islice now accepts integer-like objects
     (having an __index__ method) as start, stop, and slice arguments

   - bpo-25324(38): Tokens needed for parsing in Python moved to C.
     ‘COMMENT’, ‘NL’ and ‘ENCODING’.  This way the tokens and tok_names
     in the token module don’t get changed when you import the tokenize
     module.

   - bpo-29104(39): Fixed parsing backslashes in f-strings.

   - bpo-27945(40): Fixed various segfaults with dict when input
     collections are mutated during searching, inserting or comparing.
     Based on patches by Duane Griffin and Tim Mitchell.

   - bpo-25794(41): Fixed type.__setattr__() and type.__delattr__() for
     non-interned attribute names.  Based on patch by Eryk Sun.

   - bpo-30039(42): If a KeyboardInterrupt happens when the interpreter
     is in the middle of resuming a chain of nested ‘yield from’ or
     ‘await’ calls, it’s now correctly delivered to the innermost frame.

   - bpo-28974(43): ‘object.__format__(x, '')’ is now equivalent to
     ‘str(x)’ rather than ‘format(str(self), '')’.

   - bpo-30024(44): Circular imports involving absolute imports with
     binding a submodule to a name are now supported.

   - bpo-12414(45): sys.getsizeof() on a code object now returns the
     sizes which includes the code struct and sizes of objects which it
     references.  Patch by Donghee Na.

   - bpo-29839(46): len() now raises ValueError rather than
     OverflowError if __len__() returned a large negative integer.

   - bpo-11913(47): README.rst is now included in the list of distutils
     standard READMEs and therefore included in source distributions.

   - bpo-29914(48): Fixed default implementations of __reduce__ and
     __reduce_ex__().  object.__reduce__() no longer takes arguments,
     object.__reduce_ex__() now requires one argument.

   - bpo-29949(49): Fix memory usage regression of set and frozenset
     object.

   - bpo-29935(50): Fixed error messages in the index() method of tuple,
     list and deque when pass indices of wrong type.

   - bpo-29816(51): Shift operation now has less opportunity to raise
     OverflowError.  ValueError always is raised rather than
     OverflowError for negative counts.  Shifting zero with non-negative
     count always returns zero.

   - bpo-24821(52): Fixed the slowing down to 25 times in the searching
     of some unlucky Unicode characters.

   - bpo-29102(53): Add a unique ID to PyInterpreterState.  This makes
     it easier to identify each subinterpreter.

   - bpo-29894(54): The deprecation warning is emitted if __complex__
     returns an instance of a strict subclass of complex.  In a future
     versions of Python this can be an error.

   - bpo-29859(55): Show correct error messages when any of the
     pthread_* calls in thread_pthread.h fails.

   - bpo-29849(56): Fix a memory leak when an ImportError is raised
     during from import.

   - bpo-28856(57): Fix an oversight that %b format for bytes should
     support objects follow the buffer protocol.

   - bpo-29723(58): The ‘sys.path[0]’ initialization change for
     bpo-29139(59) caused a regression by revealing an inconsistency in
     how sys.path is initialized when executing ‘__main__’ from a
     zipfile, directory, or other import location.  The interpreter now
     consistently avoids ever adding the import location’s parent
     directory to ‘sys.path’, and ensures no other ‘sys.path’ entries
     are inadvertently modified when inserting the import location named
     on the command line.

   - bpo-29568(60): Escaped percent “%%” in the format string for
     classic string formatting no longer allows any characters between
     two percents.

   - bpo-29714(61): Fix a regression that bytes format may fail when
     containing zero bytes inside.

   - bpo-29695(62): bool(), float(), list() and tuple() no longer take
     keyword arguments.  The first argument of int() can now be passes
     only as positional argument.

   - bpo-28893(63): Set correct __cause__ for errors about invalid
     awaitables returned from __aiter__ and __anext__.

   - bpo-28876(64): ‘bool(range)’ works even if ‘len(range)’ raises
     *note OverflowError: 888.

   - bpo-29683(65): Fixes to memory allocation in _PyCode_SetExtra.
     Patch by Brian Coleman.

   - bpo-29684(66): Fix minor regression of
     PyEval_CallObjectWithKeywords.  It should raise TypeError when
     kwargs is not a dict.  But it might cause segv when args=NULL and
     kwargs is not a dict.

   - bpo-28598(67): Support __rmod__ for subclasses of str being called
     before str.__mod__.  Patch by Martijn Pieters.

   - bpo-29607(68): Fix stack_effect computation for CALL_FUNCTION_EX.
     Patch by Matthieu Dartiailh.

   - bpo-29602(69): Fix incorrect handling of signed zeros in complex
     constructor for complex subclasses and for inputs having a
     __complex__ method.  Patch by Serhiy Storchaka.

   - bpo-29347(70): Fixed possibly dereferencing undefined pointers when
     creating weakref objects.

   - bpo-29463(71): Add ‘docstring’ field to Module, ClassDef,
     FunctionDef, and AsyncFunctionDef ast nodes.  docstring is not
     first stmt in their body anymore.  It affects ‘co_firstlineno’ and
     ‘co_lnotab’ of code object for module and class.  (Reverted in
     bpo-32911(72).)

   - bpo-29438(73): Fixed use-after-free problem in key sharing dict.

   - bpo-29546(74): Set the ‘path’ and ‘name’ attribute on ImportError
     for ‘from ... import ...’.

   - bpo-29546(75): Improve from-import error message with location

   - bpo-29478(76): If max_line_length=None is specified while using the
     Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.

   - bpo-29319(77): Prevent RunMainFromImporter overwriting sys.path[0].

   - bpo-29337(78): Fixed possible BytesWarning when compare the code
     objects.  Warnings could be emitted at compile time.

   - bpo-29327(79): Fixed a crash when pass the iterable keyword
     argument to sorted().

   - bpo-29034(80): Fix memory leak and use-after-free in os module
     (path_converter).

   - bpo-29159(81): Fix regression in bytes(x) when x.__index__() raises
     Exception.

   - bpo-29049(82): Call _PyObject_GC_TRACK() lazily when calling Python
     function.  Calling function is up to 5% faster.

   - bpo-28927(83): bytes.fromhex() and bytearray.fromhex() now ignore
     all ASCII whitespace, not only spaces.  Patch by Robert Xiao.

   - bpo-28932(84): Do not include <sys/random.h> if it does not exist.

   - bpo-25677(85): Correct the positioning of the syntax error caret
     for indented blocks.  Based on patch by Michael Layzell.

   - bpo-29000(86): Fixed bytes formatting of octals with zero padding
     in alternate form.

   - bpo-18896(87): Python function can now have more than 255
     parameters.  collections.namedtuple() now supports tuples with more
     than 255 elements.

   - bpo-28596(88): The preferred encoding is UTF-8 on Android.  Patch
     written by Chi Hsuan Yen.

   - bpo-22257(89): Clean up interpreter startup (see PEP 432(90)).

   - bpo-26919(91): On Android, operating system data is now always
     encoded/decoded to/from UTF-8, instead of the locale encoding to
     avoid inconsistencies with os.fsencode() and os.fsdecode() which
     are already using UTF-8.

   - bpo-28991(92): functools.lru_cache() was susceptible to an obscure
     reentrancy bug triggerable by a monkey-patched len() function.

   - bpo-28147(93): Fix a memory leak in split-table dictionaries:
     setattr() must not convert combined table into split table.  Patch
     written by INADA Naoki.

   - bpo-28739(94): f-string expressions are no longer accepted as
     docstrings and by ast.literal_eval() even if they do not include
     expressions.

   - bpo-28512(95): Fixed setting the offset attribute of SyntaxError by
     PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

   - bpo-28918(96): Fix the cross compilation of xxlimited when Python
     has been built with Py_DEBUG defined.

   - bpo-23722(97): Rather than silently producing a class that doesn’t
     support zero-argument ‘super()’ in methods, failing to pass the new
     ‘__classcell__’ namespace entry up to ‘type.__new__’ now results in
     a ‘DeprecationWarning’ and a class that supports zero-argument
     ‘super()’.

   - bpo-28797(98): Modifying the class __dict__ inside the __set_name__
     method of a descriptor that is used inside that class no longer
     prevents calling the __set_name__ method of other descriptors.

   - bpo-28799(99): Remove the ‘PyEval_GetCallStats()’ function and
     deprecate the untested and undocumented ‘sys.callstats()’ function.
     Remove the ‘CALL_PROFILE’ special build: use the *note
     sys.setprofile(): 154d. function, *note cProfile: 27. or *note
     profile: af. to profile function calls.

   - bpo-12844(100): More than 255 arguments can now be passed to a
     function.

   - bpo-28782(101): Fix a bug in the implementation ‘yield from’ when
     checking if the next instruction is YIELD_FROM. Regression
     introduced by WORDCODE (bpo-26647(102)).

   - bpo-28774(103): Fix error position of the unicode error in ASCII
     and Latin1 encoders when a string returned by the error handler
     contains multiple non-encodable characters (non-ASCII for the ASCII
     codec, characters out of the U+0000-U+00FF range for Latin1).

   - bpo-28731(104): Optimize _PyDict_NewPresized() to create correct
     size dict.  Improve speed of dict literal with constant keys up to
     30%.

   - bpo-28532(105): Show sys.version when -V option is supplied twice.

   - bpo-27100(106): The with-statement now checks for __enter__ before
     it checks for __exit__.  This gives less confusing error messages
     when both methods are missing.  Patch by Jonathan Ellington.

   - bpo-28746(107): Fix the set_inheritable() file descriptor method on
     platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

   - bpo-26920(108): Fix not getting the locale’s charset upon
     initializing the interpreter, on platforms that do not have
     langinfo.

   - bpo-28648(109): Fixed crash in Py_DecodeLocale() in debug build on
     Mac OS X when decode astral characters.  Patch by Xiang Zhang.

   - bpo-28665(110): Improve speed of the STORE_DEREF opcode by 40%.

   - bpo-19398(111): Extra slash no longer added to sys.path components
     in case of empty compile-time PYTHONPATH components.

   - bpo-28621(112): Sped up converting int to float by reusing faster
     bits counting implementation.  Patch by Adrian Wielgosik.

   - bpo-28580(113): Optimize iterating split table values.  Patch by
     Xiang Zhang.

   - bpo-28583(114): PyDict_SetDefault didn’t combine split table when
     needed.  Patch by Xiang Zhang.

   - bpo-28128(115): Deprecation warning for invalid str and byte escape
     sequences now prints better information about where the error
     occurs.  Patch by Serhiy Storchaka and Eric Smith.

   - bpo-28509(116): dict.update() no longer allocate unnecessary large
     memory.

   - bpo-28426(117): Fixed potential crash in
     PyUnicode_AsDecodedObject() in debug build.

   - bpo-28517(118): Fixed of-by-one error in the peephole optimizer
     that caused keeping unreachable code.

   - bpo-28214(119): Improved exception reporting for problematic
     __set_name__ attributes.

   - bpo-23782(120): Fixed possible memory leak in _PyTraceback_Add()
     and exception loss in PyTraceBack_Here().

   - bpo-28183(121): Optimize and cleanup dict iteration.

   - bpo-26081(122): Added C implementation of asyncio.Future.  Original
     patch by Yury Selivanov.

   - bpo-28379(123): Added sanity checks and tests for
     PyUnicode_CopyCharacters().  Patch by Xiang Zhang.

   - bpo-28376(124): The type of long range iterator is now registered
     as Iterator.  Patch by Oren Milman.

   - bpo-28376(125): Creating instances of range_iterator by calling
     range_iterator type now is disallowed.  Calling iter() on range
     instance is the only way.  Patch by Oren Milman.

   - bpo-26906(126): Resolving special methods of uninitialized type now
     causes implicit initialization of the type instead of a fail.

   - bpo-18287(127): PyType_Ready() now checks that tp_name is not NULL.
     Original patch by Niklas Koep.

   - bpo-24098(128): Fixed possible crash when AST is changed in process
     of compiling it.

   - bpo-28201(129): Dict reduces possibility of 2nd conflict in hash
     table when hashes have same lower bits.

   - bpo-28350(130): String constants with null character no longer
     interned.

   - bpo-26617(131): Fix crash when GC runs during weakref callbacks.

   - bpo-27942(132): String constants now interned recursively in tuples
     and frozensets.

   - bpo-28289(133): ImportError.__init__ now resets not specified
     attributes.

   - bpo-21578(134): Fixed misleading error message when ImportError
     called with invalid keyword args.

   - bpo-28203(135): Fix incorrect type in complex(1.0, {2:3}) error
     message.  Patch by Soumya Sharma.

   - bpo-28086(136): Single var-positional argument of tuple subtype was
     passed unscathed to the C-defined function.  Now it is converted to
     exact tuple.

   - bpo-28214(137): Now __set_name__ is looked up on the class instead
     of the instance.

   - bpo-27955(138): Fallback on reading /dev/urandom device when the
     getrandom() syscall fails with EPERM, for example when blocked by
     SECCOMP.

   - bpo-28192(139): Don’t import readline in isolated mode.

   - bpo-27441(140): Remove some redundant assignments to ob_size in
     longobject.c.  Thanks Oren Milman.

   - bpo-27222(141): Clean up redundant code in long_rshift function.
     Thanks Oren Milman.

   - Upgrade internal unicode databases to Unicode version 9.0.0.

   - bpo-28131(142): Fix a regression in zipimport’s compile_source().
     zipimport should use the same optimization level as the
     interpreter.

   - bpo-28126(143): Replace Py_MEMCPY with memcpy().  Visual Studio can
     properly optimize memcpy().

   - bpo-28120(144): Fix dict.pop() for splitted dictionary when trying
     to remove a “pending key” (Not yet inserted in split-table).  Patch
     by Xiang Zhang.

   - bpo-26182(145): Raise DeprecationWarning when async and await
     keywords are used as variable/attribute/class/function name.

   - bpo-26182(146): Fix a refleak in code that raises
     DeprecationWarning.

   - bpo-28721(147): Fix asynchronous generators aclose() and athrow()
     to handle StopAsyncIteration propagation properly.

   - bpo-26110(148): Speed-up method calls: add LOAD_METHOD and
     CALL_METHOD opcodes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31490

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31471

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31418

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31416

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28411

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28411

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31411

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31344

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31373

   (10) https://bugs.python.org/issue?@action=redirect&bpo=30465

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30860

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31347

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31343

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31291

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31271

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31243

   (17) https://bugs.python.org/issue?@action=redirect&bpo=30721

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31070

   (19) https://bugs.python.org/issue?@action=redirect&bpo=30747

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31095

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31071

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30978

   (23) https://bugs.python.org/issue?@action=redirect&bpo=30808

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30876

   (25) https://bugs.python.org/issue?@action=redirect&bpo=30703

   (26) https://bugs.python.org/issue?@action=redirect&bpo=30765

   (27) https://bugs.python.org/issue?@action=redirect&bpo=31161

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30814

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30736

   (30) https://bugs.python.org/issue?@action=redirect&bpo=30604

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30597

   (32) https://bugs.python.org/issue?@action=redirect&bpo=30682

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30501

   (34) https://bugs.python.org/issue?@action=redirect&bpo=28180

   (35) https://peps.python.org/pep-0538/

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30486

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30537

   (38) https://bugs.python.org/issue?@action=redirect&bpo=25324

   (39) https://bugs.python.org/issue?@action=redirect&bpo=29104

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27945

   (41) https://bugs.python.org/issue?@action=redirect&bpo=25794

   (42) https://bugs.python.org/issue?@action=redirect&bpo=30039

   (43) https://bugs.python.org/issue?@action=redirect&bpo=28974

   (44) https://bugs.python.org/issue?@action=redirect&bpo=30024

   (45) https://bugs.python.org/issue?@action=redirect&bpo=12414

   (46) https://bugs.python.org/issue?@action=redirect&bpo=29839

   (47) https://bugs.python.org/issue?@action=redirect&bpo=11913

   (48) https://bugs.python.org/issue?@action=redirect&bpo=29914

   (49) https://bugs.python.org/issue?@action=redirect&bpo=29949

   (50) https://bugs.python.org/issue?@action=redirect&bpo=29935

   (51) https://bugs.python.org/issue?@action=redirect&bpo=29816

   (52) https://bugs.python.org/issue?@action=redirect&bpo=24821

   (53) https://bugs.python.org/issue?@action=redirect&bpo=29102

   (54) https://bugs.python.org/issue?@action=redirect&bpo=29894

   (55) https://bugs.python.org/issue?@action=redirect&bpo=29859

   (56) https://bugs.python.org/issue?@action=redirect&bpo=29849

   (57) https://bugs.python.org/issue?@action=redirect&bpo=28856

   (58) https://bugs.python.org/issue?@action=redirect&bpo=29723

   (59) https://bugs.python.org/issue?@action=redirect&bpo=29139

   (60) https://bugs.python.org/issue?@action=redirect&bpo=29568

   (61) https://bugs.python.org/issue?@action=redirect&bpo=29714

   (62) https://bugs.python.org/issue?@action=redirect&bpo=29695

   (63) https://bugs.python.org/issue?@action=redirect&bpo=28893

   (64) https://bugs.python.org/issue?@action=redirect&bpo=28876

   (65) https://bugs.python.org/issue?@action=redirect&bpo=29683

   (66) https://bugs.python.org/issue?@action=redirect&bpo=29684

   (67) https://bugs.python.org/issue?@action=redirect&bpo=28598

   (68) https://bugs.python.org/issue?@action=redirect&bpo=29607

   (69) https://bugs.python.org/issue?@action=redirect&bpo=29602

   (70) https://bugs.python.org/issue?@action=redirect&bpo=29347

   (71) https://bugs.python.org/issue?@action=redirect&bpo=29463

   (72) https://bugs.python.org/issue?@action=redirect&bpo=32911

   (73) https://bugs.python.org/issue?@action=redirect&bpo=29438

   (74) https://bugs.python.org/issue?@action=redirect&bpo=29546

   (75) https://bugs.python.org/issue?@action=redirect&bpo=29546

   (76) https://bugs.python.org/issue?@action=redirect&bpo=29478

   (77) https://bugs.python.org/issue?@action=redirect&bpo=29319

   (78) https://bugs.python.org/issue?@action=redirect&bpo=29337

   (79) https://bugs.python.org/issue?@action=redirect&bpo=29327

   (80) https://bugs.python.org/issue?@action=redirect&bpo=29034

   (81) https://bugs.python.org/issue?@action=redirect&bpo=29159

   (82) https://bugs.python.org/issue?@action=redirect&bpo=29049

   (83) https://bugs.python.org/issue?@action=redirect&bpo=28927

   (84) https://bugs.python.org/issue?@action=redirect&bpo=28932

   (85) https://bugs.python.org/issue?@action=redirect&bpo=25677

   (86) https://bugs.python.org/issue?@action=redirect&bpo=29000

   (87) https://bugs.python.org/issue?@action=redirect&bpo=18896

   (88) https://bugs.python.org/issue?@action=redirect&bpo=28596

   (89) https://bugs.python.org/issue?@action=redirect&bpo=22257

   (90) https://peps.python.org/pep-0432/

   (91) https://bugs.python.org/issue?@action=redirect&bpo=26919

   (92) https://bugs.python.org/issue?@action=redirect&bpo=28991

   (93) https://bugs.python.org/issue?@action=redirect&bpo=28147

   (94) https://bugs.python.org/issue?@action=redirect&bpo=28739

   (95) https://bugs.python.org/issue?@action=redirect&bpo=28512

   (96) https://bugs.python.org/issue?@action=redirect&bpo=28918

   (97) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (98) https://bugs.python.org/issue?@action=redirect&bpo=28797

   (99) https://bugs.python.org/issue?@action=redirect&bpo=28799

   (100) https://bugs.python.org/issue?@action=redirect&bpo=12844

   (101) https://bugs.python.org/issue?@action=redirect&bpo=28782

   (102) https://bugs.python.org/issue?@action=redirect&bpo=26647

   (103) https://bugs.python.org/issue?@action=redirect&bpo=28774

   (104) https://bugs.python.org/issue?@action=redirect&bpo=28731

   (105) https://bugs.python.org/issue?@action=redirect&bpo=28532

   (106) https://bugs.python.org/issue?@action=redirect&bpo=27100

   (107) https://bugs.python.org/issue?@action=redirect&bpo=28746

   (108) https://bugs.python.org/issue?@action=redirect&bpo=26920

   (109) https://bugs.python.org/issue?@action=redirect&bpo=28648

   (110) https://bugs.python.org/issue?@action=redirect&bpo=28665

   (111) https://bugs.python.org/issue?@action=redirect&bpo=19398

   (112) https://bugs.python.org/issue?@action=redirect&bpo=28621

   (113) https://bugs.python.org/issue?@action=redirect&bpo=28580

   (114) https://bugs.python.org/issue?@action=redirect&bpo=28583

   (115) https://bugs.python.org/issue?@action=redirect&bpo=28128

   (116) https://bugs.python.org/issue?@action=redirect&bpo=28509

   (117) https://bugs.python.org/issue?@action=redirect&bpo=28426

   (118) https://bugs.python.org/issue?@action=redirect&bpo=28517

   (119) https://bugs.python.org/issue?@action=redirect&bpo=28214

   (120) https://bugs.python.org/issue?@action=redirect&bpo=23782

   (121) https://bugs.python.org/issue?@action=redirect&bpo=28183

   (122) https://bugs.python.org/issue?@action=redirect&bpo=26081

   (123) https://bugs.python.org/issue?@action=redirect&bpo=28379

   (124) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (125) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (126) https://bugs.python.org/issue?@action=redirect&bpo=26906

   (127) https://bugs.python.org/issue?@action=redirect&bpo=18287

   (128) https://bugs.python.org/issue?@action=redirect&bpo=24098

   (129) https://bugs.python.org/issue?@action=redirect&bpo=28201

   (130) https://bugs.python.org/issue?@action=redirect&bpo=28350

   (131) https://bugs.python.org/issue?@action=redirect&bpo=26617

   (132) https://bugs.python.org/issue?@action=redirect&bpo=27942

   (133) https://bugs.python.org/issue?@action=redirect&bpo=28289

   (134) https://bugs.python.org/issue?@action=redirect&bpo=21578

   (135) https://bugs.python.org/issue?@action=redirect&bpo=28203

   (136) https://bugs.python.org/issue?@action=redirect&bpo=28086

   (137) https://bugs.python.org/issue?@action=redirect&bpo=28214

   (138) https://bugs.python.org/issue?@action=redirect&bpo=27955

   (139) https://bugs.python.org/issue?@action=redirect&bpo=28192

   (140) https://bugs.python.org/issue?@action=redirect&bpo=27441

   (141) https://bugs.python.org/issue?@action=redirect&bpo=27222

   (142) https://bugs.python.org/issue?@action=redirect&bpo=28131

   (143) https://bugs.python.org/issue?@action=redirect&bpo=28126

   (144) https://bugs.python.org/issue?@action=redirect&bpo=28120

   (145) https://bugs.python.org/issue?@action=redirect&bpo=26182

   (146) https://bugs.python.org/issue?@action=redirect&bpo=26182

   (147) https://bugs.python.org/issue?@action=redirect&bpo=28721

   (148) https://bugs.python.org/issue?@action=redirect&bpo=26110


File: python.info,  Node: Library<149>,  Next: Documentation<64>,  Prev: Core and Builtins<146>,  Up: Python 3 7 0 alpha 1

1.23.74.3 Library
.................

   - bpo-31499(1): xml.etree: Fix a crash when a parser is part of a
     reference cycle.

   - bpo-31482(2): ‘random.seed()’ now works with bytes in version=1

   - bpo-28556(3): typing.get_type_hints now finds the right globalns
     for classes and modules by default (when no ‘globalns’ was
     specified by the caller).

   - bpo-28556(4): Speed improvements to the ‘typing’ module.  Original
     PRs by Ivan Levkivskyi and Mitar.

   - bpo-31544(5): The C accelerator module of ElementTree ignored
     exceptions raised when looking up TreeBuilder target methods in
     XMLParser().

   - bpo-31234(6): socket.create_connection() now fixes manually a
     reference cycle: clear the variable storing the last exception on
     success.

   - bpo-31457(7): LoggerAdapter objects can now be nested.

   - bpo-31431(8): SSLContext.check_hostname now automatically sets
     SSLContext.verify_mode to ssl.CERT_REQUIRED instead of failing with
     a ValueError.

   - bpo-31233(9): socketserver.ThreadingMixIn now keeps a list of
     non-daemonic threads to wait until all these threads complete in
     server_close().

   - bpo-28638(10): Changed the implementation strategy for
     collections.namedtuple() to substantially reduce the use of exec()
     in favor of precomputed methods.  As a result, the 'verbose'
     parameter and '_source' attribute are no longer supported.  The
     benefits include 1) having a smaller memory footprint for
     applications using multiple named tuples, 2) faster creation of the
     named tuple class (approx 4x to 6x depending on how it is
     measured), and 3) minor speed-ups for instance creation using
     __new__, _make, and _replace.  (The primary patch contributor is
     Jelle Zijlstra with further improvements by INADA Naoki, Serhiy
     Storchaka, and Raymond Hettinger.)

   - bpo-31400(11): Improves SSL error handling to avoid losing error
     numbers.

   - bpo-27629(12): Make return types of SSLContext.wrap_bio() and
     SSLContext.wrap_socket() customizable.

   - bpo-28958(13): ssl.SSLContext() now uses OpenSSL error information
     when a context cannot be instantiated.

   - bpo-28182(14): The SSL module now raises SSLCertVerificationError
     when OpenSSL fails to verify the peer’s certificate.  The exception
     contains more information about the error.

   - bpo-27340(15): SSLSocket.sendall() now uses memoryview to create
     slices of data.  This fixes support for all bytes-like object.  It
     is also more efficient and avoids costly copies.

   - bpo-14191(16): A new function
     ‘argparse.ArgumentParser.parse_intermixed_args’ provides the
     ability to parse command lines where there user intermixes options
     and positional arguments.

   - bpo-31178(17): Fix string concatenation bug in rare error path in
     the subprocess module

   - bpo-31350(18): Micro-optimize ‘asyncio._get_running_loop()’ to
     become up to 10% faster.

   - bpo-31170(19): expat: Update libexpat from 2.2.3 to 2.2.4.  Fix
     copying of partial characters for UTF-8 input (libexpat bug 115):
     ‘https://github.com/libexpat/libexpat/issues/115’

   - bpo-29136(20): Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

   - bpo-1198569(21): ‘string.Template’ subclasses can optionally define
     ‘braceidpattern’ if they want to specify different placeholder
     patterns inside and outside the braces.  If None (the default) it
     falls back to ‘idpattern’.

   - bpo-31326(22): concurrent.futures.ProcessPoolExecutor.shutdown()
     now explicitly closes the call queue.  Moreover,
     shutdown(wait=True) now also join the call queue thread, to prevent
     leaking a dangling thread.

   - bpo-27144(23): The ‘map()’ and ‘as_completed()’ iterators in
     ‘concurrent.futures’ now avoid keeping a reference to yielded
     objects.

   - bpo-31281(24): Fix ‘fileinput.FileInput(files, inplace=True)’ when
     ‘files’ contain ‘pathlib.Path’ objects.

   - bpo-10746(25): Fix ctypes producing wrong PEP 3118(26) type codes
     for integer types.

   - bpo-27584(27): ‘AF_VSOCK’ has been added to the socket interface
     which allows communication between virtual machines and their host.

   - bpo-22536(28): The subprocess module now sets the filename when
     FileNotFoundError is raised on POSIX systems due to the executable
     or cwd not being found.

   - bpo-29741(29): Update some methods in the _pyio module to also
     accept integer types.  Patch by Oren Milman.

   - bpo-31249(30): concurrent.futures: WorkItem.run() used by
     ThreadPoolExecutor now breaks a reference cycle between an
     exception object and the WorkItem object.

   - bpo-31247(31): xmlrpc.server now explicitly breaks reference cycles
     when using sys.exc_info() in code handling exceptions.

   - bpo-23835(32): configparser: reading defaults in the
     ‘ConfigParser()’ constructor is now using ‘read_dict()’, making its
     behavior consistent with the rest of the parser.  Non-string keys
     and values in the defaults dictionary are now being implicitly
     converted to strings.  Patch by James Tocknell.

   - bpo-31238(33): pydoc: the stop() method of the private ServerThread
     class now waits until DocServer.serve_until_quit() completes and
     then explicitly sets its docserver attribute to None to break a
     reference cycle.

   - bpo-5001(34): Many asserts in ‘multiprocessing’ are now more
     informative, and some error types have been changed to more
     specific ones.

   - bpo-31109(35): Convert zipimport to use Argument Clinic.

   - bpo-30102(36): The ssl and hashlib modules now call
     OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0.  The
     function detects CPU features and enables optimizations on some CPU
     architectures such as POWER8.  Patch is based on research from
     Gustavo Serra Scalet.

   - bpo-18966(37): Non-daemonic threads created by a
     multiprocessing.Process are now joined on child exit.

   - bpo-31183(38): ‘dis’ now works with asynchronous generator and
     coroutine objects.  Patch by George Collins based on diagnosis by
     Luciano Ramalho.

   - bpo-5001(39): There are a number of uninformative asserts in the
     ‘multiprocessing’ module, as noted in issue 5001.  This change
     fixes two of the most potentially problematic ones, since they are
     in error-reporting code, in the
     ‘multiprocessing.managers.convert_to_error’ function.  (It also
     makes more informative a ValueError message.)  The only potentially
     problematic change is that the AssertionError is now a TypeError;
     however, this should also help distinguish it from an
     AssertionError being 'reported' by the function/its caller (such as
     in issue 31169).  - Patch by Allen W. Smith (drallensmith on
     github).

   - bpo-31185(40): Fixed miscellaneous errors in asyncio speedup
     module.

   - bpo-31151(41): socketserver.ForkingMixIn.server_close() now waits
     until all child processes completed to prevent leaking zombie
     processes.

   - bpo-31072(42): Add an ‘include_file’ parameter to
     ‘zipapp.create_archive()’

   - bpo-24700(43): Optimize array.array comparison.  It is now from 10x
     up to 70x faster when comparing arrays holding values of the same
     integer type.

   - bpo-31135(44): ttk: fix the destroy() method of LabeledScale and
     OptionMenu classes.  Call the parent destroy() method even if the
     used attribute doesn’t exist.  The LabeledScale.destroy() method
     now also explicitly clears label and scale attributes to help the
     garbage collector to destroy all widgets.

   - bpo-31107(45): Fix ‘copyreg._slotnames()’ mangled attribute
     calculation for classes whose name begins with an underscore.
     Patch by Shane Harvey.

   - bpo-31080(46): Allow ‘logging.config.fileConfig’ to accept kwargs
     and/or args.

   - bpo-30897(47): ‘pathlib.Path’ objects now include an ‘is_mount()’
     method (only implemented on POSIX). This is similar to
     ‘os.path.ismount(p)’.  Patch by Cooper Ry Lees.

   - bpo-31061(48): Fixed a crash when using asyncio and threads.

   - bpo-30987(49): Added support for CAN ISO-TP protocol in the socket
     module.

   - bpo-30522(50): Added a ‘setStream’ method to
     ‘logging.StreamHandler’ to allow the stream to be set after
     creation.

   - bpo-30502(51): Fix handling of long oids in ssl.  Based on patch by
     Christian Heimes.

   - bpo-5288(52): Support tzinfo objects with sub-minute offsets.

   - bpo-30919(53): Fix shared memory performance regression in
     multiprocessing in 3.x.  Shared memory used anonymous memory
     mappings in 2.x, while 3.x mmaps actual files.  Try to be careful
     to do as little disk I/O as possible.

   - bpo-26732(54): Fix too many fds in processes started with the
     “forkserver” method.  A child process would inherit as many fds as
     the number of still-running children.

   - bpo-29403(55): Fix ‘unittest.mock’’s autospec to not fail on
     method-bound builtin functions.  Patch by Aaron Gallagher.

   - bpo-30961(56): Fix decrementing a borrowed reference in
     tracemalloc.

   - bpo-19896(57): Fix multiprocessing.sharedctypes to recognize
     typecodes ‘'q'’ and ‘'Q'’.

   - bpo-30946(58): Remove obsolete code in readline module for
     platforms where GNU readline is older than 2.1 or where select() is
     not available.

   - bpo-25684(59): Change ‘ttk.OptionMenu’ radiobuttons to be unique
     across instances of ‘OptionMenu’.

   - bpo-30886(60): Fix multiprocessing.Queue.join_thread(): it now
     waits until the thread completes, even if the thread was started by
     the same process which created the queue.

   - bpo-29854(61): Fix segfault in readline when using readline’s
     history-size option.  Patch by Nir Soffer.

   - bpo-30794(62): Added multiprocessing.Process.kill method to
     terminate using the SIGKILL signal on Unix.

   - bpo-30319(63): socket.close() now ignores ECONNRESET error.

   - bpo-30828(64): Fix out of bounds write in
     ‘asyncio.CFuture.remove_done_callback()’.

   - bpo-30302(65): Use keywords in the ‘repr’ of ‘datetime.timedelta’.

   - bpo-30807(66): signal.setitimer() may disable the timer when passed
     a tiny value.  Tiny values (such as 1e-6) are valid non-zero values
     for setitimer(), which is specified as taking
     microsecond-resolution intervals.  However, on some platform, our
     conversion routine could convert 1e-6 into a zero interval,
     therefore disabling the timer instead of (re-)scheduling it.

   - bpo-30441(67): Fix bug when modifying os.environ while iterating
     over it

   - bpo-29585(68): Avoid importing ‘sysconfig’ from ‘site’ to improve
     startup speed.  Python startup is about 5% faster on Linux and 30%
     faster on macOS.

   - bpo-29293(69): Add missing parameter “n” on
     multiprocessing.Condition.notify().  The doc claims
     multiprocessing.Condition behaves like threading.Condition, but its
     notify() method lacked the optional “n” argument (to specify the
     number of sleepers to wake up) that threading.Condition.notify()
     accepts.

   - bpo-30532(70): Fix email header value parser dropping folding white
     space in certain cases.

   - bpo-30596(71): Add a ‘close()’ method to ‘multiprocessing.Process’.

   - bpo-9146(72): Fix a segmentation fault in _hashopenssl when
     standard hash functions such as md5 are not available in the linked
     OpenSSL library.  As in some special FIPS-140 build environments.

   - bpo-29169(73): Update zlib to 1.2.11.

   - bpo-30119(74): ftplib.FTP.putline() now throws ValueError on
     commands that contains CR or LF. Patch by Donghee Na.

   - bpo-30879(75): os.listdir() and os.scandir() now emit bytes names
     when called with bytes-like argument.

   - bpo-30746(76): Prohibited the ‘=’ character in environment variable
     names in ‘os.putenv()’ and ‘os.spawn*()’.

   - bpo-30664(77): The description of a unittest subtest now preserves
     the order of keyword arguments of TestCase.subTest().

   - bpo-21071(78): struct.Struct.format type is now *note str: 44f.
     instead of *note bytes: 1c2.

   - bpo-29212(79): Fix concurrent.futures.thread.ThreadPoolExecutor
     threads to have a non repr() based thread name by default when no
     thread_name_prefix is supplied.  They will now identify themselves
     as “ThreadPoolExecutor-y_n”.

   - bpo-29755(80): Fixed the lgettext() family of functions in the
     gettext module.  They now always return bytes.

   - bpo-30616(81): Functional API of enum allows to create empty enums.
     Patched by Donghee Na

   - bpo-30038(82): Fix race condition between signal delivery and
     wakeup file descriptor.  Patch by Nathaniel Smith.

   - bpo-23894(83): lib2to3 now recognizes ‘rb'...'’ and ‘f'...'’
     strings.

   - bpo-24744(84): pkgutil.walk_packages function now raises ValueError
     if 'path' is a string.  Patch by Sanyam Khurana.

   - bpo-24484(85): Avoid race condition in multiprocessing cleanup.

   - bpo-30589(86): Fix multiprocessing.Process.exitcode to return the
     opposite of the signal number when the process is killed by a
     signal (instead of 255) when using the “forkserver” method.

   - bpo-28994(87): The traceback no longer displayed for SystemExit
     raised in a callback registered by atexit.

   - bpo-30508(88): Don’t log exceptions if Task/Future “cancel()”
     method was called.

   - bpo-30645(89): Fix path calculation in ‘imp.load_package()’, fixing
     it for cases when a package is only shipped with bytecodes.  Patch
     by Alexandru Ardelean.

   - bpo-11822(90): The dis.dis() function now is able to disassemble
     nested code objects.

   - bpo-30624(91): selectors does not take KeyboardInterrupt and
     SystemExit into account, leaving a fd in a bad state in case of
     error.  Patch by Giampaolo Rodola’.

   - bpo-30595(92): multiprocessing.Queue.get() with a timeout now polls
     its reader in non-blocking mode if it succeeded to acquire the lock
     but the acquire took longer than the timeout.

   - bpo-28556(93): Updates to typing module: Add generic
     AsyncContextManager, add support for ContextManager on all
     versions.  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

   - bpo-30605(94): re.compile() no longer raises a BytesWarning when
     compiling a bytes instance with misplaced inline modifier.  Patch
     by Roy Williams.

   - bpo-29870(95): Fix ssl sockets leaks when connection is aborted in
     asyncio/ssl implementation.  Patch by Michaël Sghaïer.

   - bpo-29743(96): Closing transport during handshake process leaks
     open socket.  Patch by Nikolay Kim

   - bpo-27585(97): Fix waiter cancellation in asyncio.Lock.  Patch by
     Mathieu Sornay.

   - bpo-30014(98): modify() method of poll(), epoll() and devpoll()
     based classes of selectors module is around 10% faster.  Patch by
     Giampaolo Rodola’.

   - bpo-30418(99): On Windows, subprocess.Popen.communicate() now also
     ignore EINVAL on stdin.write() if the child process is still
     running but closed the pipe.

   - bpo-30463(100): Addded empty __slots__ to abc.ABC. This allows
     subclassers to deny __dict__ and __weakref__ creation.  Patch by
     Aaron Hall.

   - bpo-30520(101): Loggers are now pickleable.

   - bpo-30557(102): faulthandler now correctly filters and displays
     exception codes on Windows

   - bpo-30526(103): Add TextIOWrapper.reconfigure() and a
     TextIOWrapper.write_through attribute.

   - bpo-30245(104): Fix possible overflow when organize
     struct.pack_into error message.  Patch by Yuan Liu.

   - bpo-30378(105): Fix the problem that logging.handlers.SysLogHandler
     cannot handle IPv6 addresses.

   - bpo-16500(106): Allow registering at-fork handlers.

   - bpo-30470(107): Deprecate invalid ctypes call protection on
     Windows.  Patch by Mariatta Wijaya.

   - bpo-30414(108): multiprocessing.Queue._feed background running
     thread do not break from main loop on exception.

   - bpo-30003(109): Fix handling escape characters in HZ codec.  Based
     on patch by Ma Lin.

   - bpo-30149(110): inspect.signature() now supports callables with
     variable-argument parameters wrapped with partialmethod.  Patch by
     Donghee Na.

   - bpo-30436(111): importlib.find_spec() raises ModuleNotFoundError
     instead of AttributeError if the specified parent module is not a
     package (i.e.  lacks a __path__ attribute).

   - bpo-30301(112): Fix AttributeError when using SimpleQueue.empty()
     under 'spawn' and 'forkserver' start methods.

   - bpo-30375(113): Warnings emitted when compile a regular expression
     now always point to the line in the user code.  Previously they
     could point into inners of the re module if emitted from inside of
     groups or conditionals.

   - bpo-30329(114): imaplib and poplib now catch the Windows socket
     WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
     operation was attempted.  This error occurs sometimes on SSL
     connections.

   - bpo-29196(115): Removed previously deprecated in Python 2.4 classes
     Plist, Dict and _InternalDict in the plistlib module.  Dict values
     in the result of functions readPlist() and readPlistFromBytes() are
     now normal dicts.  You no longer can use attribute access to access
     items of these dictionaries.

   - bpo-9850(116): The ‘macpath’ is now deprecated and will be removed
     in Python 3.8.

   - bpo-30299(117): Compiling regular expression in debug mode on
     CPython now displays the compiled bytecode in human readable form.

   - bpo-30048(118): Fixed ‘Task.cancel()’ can be ignored when the task
     is running coroutine and the coroutine returned without any more
     ‘await’.

   - bpo-30266(119): contextlib.AbstractContextManager now supports
     anti-registration by setting __enter__ = None or __exit__ = None,
     following the pattern introduced in bpo-25958(120).  Patch by Jelle
     Zijlstra.

   - bpo-30340(121): Enhanced regular expressions optimization.  This
     increased the performance of matching some patterns up to 25 times.

   - bpo-30298(122): Weaken the condition of deprecation warnings for
     inline modifiers.  Now allowed several subsequential inline
     modifiers at the start of the pattern (e.g.  ‘'(?i)(?s)...'’).  In
     verbose mode whitespaces and comments now are allowed before and
     between inline modifiers (e.g.  ‘'(?x) (?i) (?s)...'’).

   - bpo-30285(123): Optimized case-insensitive matching and searching
     of regular expressions.

   - bpo-29990(124): Fix range checking in GB18030 decoder.  Original
     patch by Ma Lin.

   - bpo-29979(125): rewrite cgi.parse_multipart, reusing the
     FieldStorage class and making its results consistent with those of
     FieldStorage for multipart/form-data requests.  Patch by Pierre
     Quentel.

   - bpo-30243(126): Removed the __init__ methods of _json’s scanner and
     encoder.  Misusing them could cause memory leaks or crashes.  Now
     scanner and encoder objects are completely initialized in the
     __new__ methods.

   - bpo-30215(127): Compiled regular expression objects with the
     re.LOCALE flag no longer depend on the locale at compile time.
     Only the locale at matching time affects the result of matching.

   - bpo-30185(128): Avoid KeyboardInterrupt tracebacks in forkserver
     helper process when Ctrl-C is received.

   - bpo-30103(129): binascii.b2a_uu() and uu.encode() now support using
     ‘'`'’ as zero instead of space.

   - bpo-28556(130): Various updates to typing module: add
     typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes.
     Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

   - bpo-30205(131): Fix getsockname() for unbound AF_UNIX sockets on
     Linux.

   - bpo-30228(132): The seek() and tell() methods of io.FileIO now set
     the internal seekable attribute to avoid one syscall on open() (in
     buffered or text mode).

   - bpo-30190(133): unittest’s assertAlmostEqual and
     assertNotAlmostEqual provide a better message in case of failure
     which includes the difference between left and right arguments.
     (patch by Giampaolo Rodola’)

   - bpo-30101(134): Add support for curses.A_ITALIC.

   - bpo-29822(135): inspect.isabstract() now works during
     __init_subclass__.  Patch by Nate Soares.

   - bpo-29960(136): Preserve generator state when
     _random.Random.setstate() raises an exception.  Patch by Bryan
     Olson.

   - bpo-30070(137): Fixed leaks and crashes in errors handling in the
     parser module.

   - bpo-22352(138): Column widths in the output of dis.dis() are now
     adjusted for large line numbers and instruction offsets.

   - bpo-30061(139): Fixed crashes in IOBase methods __next__() and
     readlines() when readline() or __next__() respectively return
     non-sizeable object.  Fixed possible other errors caused by not
     checking results of PyObject_Size(), PySequence_Size(), or
     PyMapping_Size().

   - bpo-30218(140): Fix PathLike support for shutil.unpack_archive.
     Patch by Jelle Zijlstra.

   - bpo-10076(141): Compiled regular expression and match objects in
     the re module now support copy.copy() and copy.deepcopy() (they are
     considered atomic).

   - bpo-30068(142): _io._IOBase.readlines will check if it’s closed
     first when hint is present.

   - bpo-29694(143): Fixed race condition in pathlib mkdir with flags
     parents=True.  Patch by Armin Rigo.

   - bpo-29692(144): Fixed arbitrary unchaining of RuntimeError
     exceptions in contextlib.contextmanager.  Patch by Siddharth
     Velankar.

   - bpo-26187(145): Test that sqlite3 trace callback is not called
     multiple times when schema is changing.  Indirectly fixed by
     switching to use sqlite3_prepare_v2() in bpo-9303(146).  Patch by
     Aviv Palivoda.

   - bpo-30017(147): Allowed calling the close() method of the zip entry
     writer object multiple times.  Writing to a closed writer now
     always produces a ValueError.

   - bpo-29998(148): Pickling and copying ImportError now preserves name
     and path attributes.

   - bpo-29995(149): re.escape() now escapes only regex special
     characters.

   - bpo-29962(150): Add math.remainder operation, implementing
     remainder as specified in IEEE 754.

   - bpo-29649(151): Improve struct.pack_into() exception messages for
     problems with the buffer size and offset.  Patch by Andrew Nester.

   - bpo-29654(152): Support If-Modified-Since HTTP header (browser
     cache).  Patch by Pierre Quentel.

   - bpo-29931(153): Fixed comparison check for ipaddress.ip_interface
     objects.  Patch by Sanjay Sundaresan.

   - bpo-29953(154): Fixed memory leaks in the replace() method of
     datetime and time objects when pass out of bound fold argument.

   - bpo-29942(155): Fix a crash in itertools.chain.from_iterable when
     encountering long runs of empty iterables.

   - bpo-10030(156): Sped up reading encrypted ZIP files by 2 times.

   - bpo-29204(157): Element.getiterator() and the html parameter of
     XMLParser() were deprecated only in the documentation (since Python
     3.2 and 3.4 correspondingly).  Now using them emits a deprecation
     warning.

   - bpo-27863(158): Fixed multiple crashes in ElementTree caused by
     race conditions and wrong types.

   - bpo-25996(159): Added support of file descriptors in os.scandir()
     on Unix.  os.fwalk() is sped up by 2 times by using os.scandir().

   - bpo-28699(160): Fixed a bug in pools in multiprocessing.pool that
     raising an exception at the very first of an iterable may swallow
     the exception or make the program hang.  Patch by Davin Potts and
     Xiang Zhang.

   - bpo-23890(161): unittest.TestCase.assertRaises() now manually
     breaks a reference cycle to not keep objects alive longer than
     expected.

   - bpo-29901(162): The zipapp module now supports general path-like
     objects, not just pathlib.Path.

   - bpo-25803(163): Avoid incorrect errors raised by
     Path.mkdir(exist_ok=True) when the OS gives priority to errors such
     as EACCES over EEXIST.

   - bpo-29861(164): Release references to tasks, their arguments and
     their results as soon as they are finished in multiprocessing.Pool.

   - bpo-19930(165): The mode argument of os.makedirs() no longer
     affects the file permission bits of newly created
     intermediate-level directories.

   - bpo-29884(166): faulthandler: Restore the old sigaltstack during
     teardown.  Patch by Christophe Zeitouny.

   - bpo-25455(167): Fixed crashes in repr of recursive buffered
     file-like objects.

   - bpo-29800(168): Fix crashes in partial.__repr__ if the keys of
     partial.keywords are not strings.  Patch by Michael Seifert.

   - bpo-8256(169): Fixed possible failing or crashing input() if
     attributes “encoding” or “errors” of sys.stdin or sys.stdout are
     not set or are not strings.

   - bpo-28692(170): Using non-integer value for selecting a plural form
     in gettext is now deprecated.

   - bpo-26121(171): Use C library implementation for math functions
     erf() and erfc().

   - bpo-29619(172): os.stat() and os.DirEntry.inode() now convert inode
     (st_ino) using unsigned integers.

   - bpo-28298(173): Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’
     from accepting big intables (objects that have __int__) as
     elements.

   - bpo-29645(174): Speed up importing the webbrowser module.
     webbrowser.register() is now thread-safe.

   - bpo-28231(175): The zipfile module now accepts path-like objects
     for external paths.

   - bpo-26915(176): index() and count() methods of
     collections.abc.Sequence now check identity before checking
     equality when do comparisons.

   - bpo-28682(177): Added support for bytes paths in os.fwalk().

   - bpo-29728(178): Add new ‘socket.TCP_NOTSENT_LOWAT’ (Linux 3.12)
     constant.  Patch by Nathaniel J. Smith.

   - bpo-29623(179): Allow use of path-like object as a single argument
     in ConfigParser.read().  Patch by David Ellis.

   - bpo-9303(180): Migrate sqlite3 module to _v2 API. Patch by Aviv
     Palivoda.

   - bpo-28963(181): Fix out of bound iteration in
     asyncio.Future.remove_done_callback implemented in C.

   - bpo-29704(182): asyncio.subprocess.SubprocessStreamProtocol no
     longer closes before all pipes are closed.

   - bpo-29271(183): Fix Task.current_task and Task.all_tasks
     implemented in C to accept None argument as their pure Python
     implementation.

   - bpo-29703(184): Fix asyncio to support instantiation of new event
     loops in child processes.

   - bpo-29615(185): SimpleXMLRPCDispatcher no longer chains KeyError
     (or any other exception) to exception(s) raised in the dispatched
     methods.  Patch by Petr Motejlek.

   - bpo-7769(186): Method register_function() of
     xmlrpc.server.SimpleXMLRPCDispatcher and its subclasses can now be
     used as a decorator.

   - bpo-29376(187): Fix assertion error in
     threading._DummyThread.is_alive().

   - bpo-28624(188): Add a test that checks that cwd parameter of
     Popen() accepts PathLike objects.  Patch by Sayan Chowdhury.

   - bpo-28518(189): Start a transaction implicitly before a DML
     statement.  Patch by Aviv Palivoda.

   - bpo-29742(190): get_extra_info() raises exception if get called on
     closed ssl transport.  Patch by Nikolay Kim.

   - bpo-16285(191): urllib.parse.quote is now based on RFC 3986 and
     hence includes ‘~’ in the set of characters that is not quoted by
     default.  Patch by Christian Theune and Ratnadeep Debnath.

   - bpo-29532(192): Altering a kwarg dictionary passed to
     functools.partial() no longer affects a partial object after
     creation.

   - bpo-29110(193): Fix file object leak in aifc.open() when file is
     given as a filesystem path and is not in valid AIFF format.  Patch
     by Anthony Zhang.

   - bpo-22807(194): Add uuid.SafeUUID and uuid.UUID.is_safe to relay
     information from the platform about whether generated UUIDs are
     generated with a multiprocessing safe method.

   - bpo-29576(195): Improve some deprecations in importlib.  Some
     deprecated methods now emit DeprecationWarnings and have better
     descriptive messages.

   - bpo-29534(196): Fixed different behaviour of Decimal.from_float()
     for _decimal and _pydecimal.  Thanks Andrew Nester.

   - bpo-10379(197): locale.format_string now supports the ‘monetary’
     keyword argument, and locale.format is deprecated.

   - bpo-29851(198): importlib.reload() now raises ModuleNotFoundError
     if the module lacks a spec.

   - bpo-28556(199): Various updates to typing module: typing.Counter,
     typing.ChainMap, improved ABC caching, etc.  Original PRs by Jelle
     Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

   - bpo-29100(200): Fix datetime.fromtimestamp() regression introduced
     in Python 3.6.0: check minimum and maximum years.

   - bpo-29416(201): Prevent infinite loop in pathlib.Path.mkdir

   - bpo-29444(202): Fixed out-of-bounds buffer access in the group()
     method of the match object.  Based on patch by WGH.

   - bpo-29377(203): Add WrapperDescriptorType, MethodWrapperType, and
     MethodDescriptorType built-in types to types module.  Original
     patch by Manuel Krebber.

   - bpo-29218(204): Unused install_misc command is now removed.  It has
     been documented as unused since 2000.  Patch by Eric N. Vander
     Weele.

   - bpo-29368(205): The extend() method is now called instead of the
     append() method when unpickle collections.deque and other list-like
     objects.  This can speed up unpickling to 2 times.

   - bpo-29338(206): The help of a builtin or extension class now
     includes the constructor signature if __text_signature__ is
     provided for the class.

   - bpo-29335(207): Fix subprocess.Popen.wait() when the child process
     has exited to a stopped instead of terminated state (ex: when under
     ptrace).

   - bpo-29290(208): Fix a regression in argparse that help messages
     would wrap at non-breaking spaces.

   - bpo-28735(209): Fixed the comparison of mock.MagickMock with
     mock.ANY.

   - bpo-29197(210): Removed deprecated function ntpath.splitunc().

   - bpo-29210(211): Removed support of deprecated argument “exclude” in
     tarfile.TarFile.add().

   - bpo-29219(212): Fixed infinite recursion in the repr of
     uninitialized ctypes.CDLL instances.

   - bpo-29192(213): Removed deprecated features in the http.cookies
     module.

   - bpo-29193(214): A format string argument for
     string.Formatter.format() is now positional-only.

   - bpo-29195(215): Removed support of deprecated undocumented keyword
     arguments in methods of regular expression objects.

   - bpo-28969(216): Fixed race condition in C implementation of
     functools.lru_cache.  KeyError could be raised when cached function
     with full cache was simultaneously called from different threads
     with the same uncached arguments.

   - bpo-20804(217): The unittest.mock.sentinel attributes now preserve
     their identity when they are copied or pickled.

   - bpo-29142(218): In urllib.request, suffixes in no_proxy environment
     variable with leading dots could match related hostnames again
     (e.g.  .b.c matches a.b.c).  Patch by Milan Oberkirch.

   - bpo-28961(219): Fix unittest.mock._Call helper: don’t ignore the
     name parameter anymore.  Patch written by Jiajun Huang.

   - bpo-15812(220): inspect.getframeinfo() now correctly shows the
     first line of a context.  Patch by Sam Breese.

   - bpo-28985(221): Update authorizer constants in sqlite3 module.
     Patch by Dingyuan Wang.

   - bpo-29079(222): Prevent infinite loop in pathlib.resolve() on
     Windows

   - bpo-13051(223): Fixed recursion errors in large or resized
     curses.textpad.Textbox.  Based on patch by Tycho Andersen.

   - bpo-9770(224): curses.ascii predicates now work correctly with
     negative integers.

   - bpo-28427(225): old keys should not remove new values from
     WeakValueDictionary when collecting from another thread.

   - bpo-28923(226): Remove editor artifacts from Tix.py.

   - bpo-28871(227): Fixed a crash when deallocate deep ElementTree.

   - bpo-19542(228): Fix bugs in WeakValueDictionary.setdefault() and
     WeakValueDictionary.pop() when a GC collection happens in another
     thread.

   - bpo-20191(229): Fixed a crash in resource.prlimit() when passing a
     sequence that doesn’t own its elements as limits.

   - bpo-16255(230): subprocess.Popen uses /system/bin/sh on Android as
     the shell, instead of /bin/sh.

   - bpo-28779(231): multiprocessing.set_forkserver_preload() would
     crash the forkserver process if a preloaded module instantiated
     some multiprocessing objects such as locks.

   - bpo-26937(232): The chown() method of the tarfile.TarFile class
     does not fail now when the grp module cannot be imported, as for
     example on Android platforms.

   - bpo-28847(233): dbm.dumb now supports reading read-only files and
     no longer writes the index file when it is not changed.  A
     deprecation warning is now emitted if the index file is missed and
     recreated in the ‘r’ and ‘w’ modes (will be an error in future
     Python releases).

   - bpo-27030(234): Unknown escapes consisting of ‘'\'’ and an ASCII
     letter in re.sub() replacement templates regular expressions now
     are errors.

   - bpo-28835(235): Fix a regression introduced in
     warnings.catch_warnings(): call warnings.showwarning() if it was
     overridden inside the context manager.

   - bpo-27172(236): To assist with upgrades from 2.7, the previously
     documented deprecation of ‘inspect.getfullargspec()’ has been
     reversed.  This decision may be revisited again after the Python
     2.7 branch is no longer officially supported.

   - bpo-28740(237): Add sys.getandroidapilevel(): return the build time
     API version of Android as an integer.  Function only available on
     Android.

   - bpo-26273(238): Add new ‘socket.TCP_CONGESTION’ (Linux 2.6.13) and
     ‘socket.TCP_USER_TIMEOUT’ (Linux 2.6.37) constants.  Patch written
     by Omar Sandoval.

   - bpo-28752(239): Restored the __reduce__() methods of datetime
     objects.

   - bpo-28727(240): Regular expression patterns, _sre.SRE_Pattern
     objects created by re.compile(), become comparable (only x==y and
     x!=y operators).  This change should fix the bpo-18383(241): don’t
     duplicate warning filters when the warnings module is reloaded
     (thing usually only done in unit tests).

   - bpo-20572(242): Remove the subprocess.Popen.wait endtime parameter.
     It was deprecated in 3.4 and undocumented prior to that.

   - bpo-25659(243): In ctypes, prevent a crash calling the
     from_buffer() and from_buffer_copy() methods on abstract classes
     like Array.

   - bpo-28548(244): In the “http.server” module, parse the protocol
     version if possible, to avoid using HTTP 0.9 in some error
     responses.

   - bpo-19717(245): Makes Path.resolve() succeed on paths that do not
     exist.  Patch by Vajrasky Kok

   - bpo-28563(246): Fixed possible DoS and arbitrary code execution
     when handle plural form selections in the gettext module.  The
     expression parser now supports exact syntax supported by GNU
     gettext.

   - bpo-28387(247): Fixed possible crash in _io.TextIOWrapper
     deallocator when the garbage collector is invoked in other thread.
     Based on patch by Sebastian Cufre.

   - bpo-27517(248): LZMA compressor and decompressor no longer raise
     exceptions if given empty data twice.  Patch by Benjamin Fogle.

   - bpo-28549(249): Fixed segfault in curses’s addch() with ncurses6.

   - bpo-28449(250): tarfile.open() with mode “r” or “r:” now tries to
     open a tar file with compression before trying to open it without
     compression.  Otherwise it had 50% chance failed with
     ignore_zeros=True.

   - bpo-23262(251): The webbrowser module now supports Firefox 36+ and
     derived browsers.  Based on patch by Oleg Broytman.

   - bpo-24241(252): The webbrowser in an X environment now prefers
     using the default browser directly.  Also, the webbrowser
     register() function now has a documented ‘preferred’ argument, to
     specify browsers to be returned by get() with no arguments.  Patch
     by David Steele

   - bpo-27939(253): Fixed bugs in tkinter.ttk.LabeledScale and
     tkinter.Scale caused by representing the scale as float value
     internally in Tk.  tkinter.IntVar now works if float value is set
     to underlying Tk variable.

   - bpo-28255(254): calendar.TextCalendar.prweek() no longer prints a
     space after a weeks’s calendar.  calendar.TextCalendar.pryear() no
     longer prints redundant newline after a year’s calendar.  Based on
     patch by Xiang Zhang.

   - bpo-28255(255): calendar.TextCalendar.prmonth() no longer prints a
     space at the start of new line after printing a month’s calendar.
     Patch by Xiang Zhang.

   - bpo-20491(256): The textwrap.TextWrapper class now honors
     non-breaking spaces.  Based on patch by Kaarle Ritvanen.

   - bpo-28353(257): os.fwalk() no longer fails on broken links.

   - bpo-28430(258): Fix iterator of C implemented asyncio.Future
     doesn’t accept non-None value is passed to it.send(val).

   - bpo-27025(259): Generated names for Tkinter widgets now start by
     the “!” prefix for readability.

   - bpo-25464(260): Fixed HList.header_exists() in tkinter.tix module
     by addin a workaround to Tix library bug.

   - bpo-28488(261): shutil.make_archive() no longer adds entry “./” to
     ZIP archive.

   - bpo-25953(262): re.sub() now raises an error for invalid numerical
     group reference in replacement template even if the pattern is not
     found in the string.  Error message for invalid group reference now
     includes the group index and the position of the reference.  Based
     on patch by SilentGhost.

   - bpo-28469(263): timeit now uses the sequence 1, 2, 5, 10, 20, 50,…
     instead of 1, 10, 100,… for autoranging.

   - bpo-28115(264): Command-line interface of the zipfile module now
     uses argparse.  Added support of long options.

   - bpo-18219(265): Optimize csv.DictWriter for large number of
     columns.  Patch by Mariatta Wijaya.

   - bpo-28448(266): Fix C implemented asyncio.Future didn’t work on
     Windows.

   - bpo-23214(267): In the “io” module, the argument to BufferedReader
     and BytesIO’s read1() methods is now optional and can be -1,
     matching the BufferedIOBase specification.

   - bpo-28480(268): Fix error building socket module when
     multithreading is disabled.

   - bpo-28240(269): timeit: remove ‘-c/--clock’ and ‘-t/--time’ command
     line options which were deprecated since Python 3.3.

   - bpo-28240(270): timeit now repeats the benchmarks 5 times instead
     of only 3 to make benchmarks more reliable.

   - bpo-28240(271): timeit autorange now uses a single loop iteration
     if the benchmark takes less than 10 seconds, instead of 10
     iterations.  “python3 -m timeit -s ‘import time’ ‘time.sleep(1)’”
     now takes 4 seconds instead of 40 seconds.

   - Distutils.sdist now looks for README and setup.py files with case
     sensitivity.  This behavior matches that found in Setuptools 6.0
     and later.  See setuptools 100(272) for rationale.

   - bpo-24452(273): Make webbrowser support Chrome on Mac OS X. Patch
     by Ned Batchelder.

   - bpo-20766(274): Fix references leaked by pdb in the handling of
     SIGINT handlers.

   - bpo-27998(275): Fixed bytes path support in os.scandir() on
     Windows.  Patch by Eryk Sun.

   - bpo-28317(276): The disassembler now decodes FORMAT_VALUE argument.

   - bpo-28380(277): unittest.mock Mock autospec functions now properly
     support assert_called, assert_not_called, and assert_called_once.

   - bpo-28229(278): lzma module now supports pathlib.

   - bpo-28321(279): Fixed writing non-BMP characters with binary format
     in plistlib.

   - bpo-28225(280): bz2 module now supports pathlib.  Initial patch by
     Ethan Furman.

   - bpo-28227(281): gzip now supports pathlib.  Patch by Ethan Furman.

   - bpo-28332(282): Deprecated silent truncations in socket.htons and
     socket.ntohs.  Original patch by Oren Milman.

   - bpo-27358(283): Optimized merging var-keyword arguments and
     improved error message when passing a non-mapping as a var-keyword
     argument.

   - bpo-28257(284): Improved error message when passing a non-iterable
     as a var-positional argument.  Added opcode
     BUILD_TUPLE_UNPACK_WITH_CALL.

   - bpo-28322(285): Fixed possible crashes when unpickle itertools
     objects from incorrect pickle data.  Based on patch by John Leitch.

   - bpo-28228(286): imghdr now supports pathlib.

   - bpo-28226(287): compileall now supports pathlib.

   - bpo-28314(288): Fix function declaration (C flags) for the
     getiterator() method of xml.etree.ElementTree.Element.

   - bpo-28148(289): Stop using localtime() and gmtime() in the time
     module.  Introduced platform independent _PyTime_localtime API that
     is similar to POSIX localtime_r, but available on all platforms.
     Patch by Ed Schouten.

   - bpo-28253(290): Fixed calendar functions for extreme months:
     0001-01 and 9999-12.  Methods itermonthdays() and itermonthdays2()
     are reimplemented so that they don’t call itermonthdates() which
     can cause datetime.date under/overflow.

   - bpo-28275(291): Fixed possible use after free in the decompress()
     methods of the LZMADecompressor and BZ2Decompressor classes.
     Original patch by John Leitch.

   - bpo-27897(292): Fixed possible crash in
     sqlite3.Connection.create_collation() if pass invalid string-like
     object as a name.  Patch by Xiang Zhang.

   - bpo-18844(293): random.choices() now has k as a keyword-only
     argument to improve the readability of common cases and come into
     line with the signature used in other languages.

   - bpo-18893(294): Fix invalid exception handling in
     Lib/ctypes/macholib/dyld.py.  Patch by Madison May.

   - bpo-27611(295): Fixed support of default root window in the
     tkinter.tix module.  Added the master parameter in the DisplayStyle
     constructor.

   - bpo-27348(296): In the traceback module, restore the formatting of
     exception messages like “Exception: None”.  This fixes a regression
     introduced in 3.5a2.

   - bpo-25651(297): Allow false values to be used for msg parameter of
     subTest().

   - bpo-27778(298): Fix a memory leak in os.getrandom() when the
     getrandom() is interrupted by a signal and a signal handler raises
     a Python exception.

   - bpo-28200(299): Fix memory leak on Windows in the os module (fix
     path_converter() function).

   - bpo-25400(300): RobotFileParser now correctly returns default
     values for crawl_delay and request_rate.  Initial patch by Peter
     Wirtz.

   - bpo-27932(301): Prevent memory leak in win32_ver().

   - Fix UnboundLocalError in socket._sendfile_use_sendfile.

   - bpo-28075(302): Check for ERROR_ACCESS_DENIED in Windows
     implementation of os.stat().  Patch by Eryk Sun.

   - bpo-22493(303): Warning message emitted by using inline flags in
     the middle of regular expression now contains a (truncated) regex
     pattern.  Patch by Tim Graham.

   - bpo-25270(304): Prevent codecs.escape_encode() from raising
     SystemError when an empty bytestring is passed.

   - bpo-28181(305): Get antigravity over HTTPS. Patch by Kaartic
     Sivaraam.

   - bpo-25895(306): Enable WebSocket URL schemes in
     urllib.parse.urljoin.  Patch by Gergely Imreh and Markus
     Holtermann.

   - bpo-28114(307): Fix a crash in parse_envlist() when env contains
     byte strings.  Patch by Eryk Sun.

   - bpo-27599(308): Fixed buffer overrun in binascii.b2a_qp() and
     binascii.a2b_qp().

   - bpo-27906(309): Fix socket accept exhaustion during high TCP
     traffic.  Patch by Kevin Conway.

   - bpo-28174(310): Handle when SO_REUSEPORT isn’t properly supported.
     Patch by Seth Michael Larson.

   - bpo-26654(311): Inspect functools.partial in
     asyncio.Handle.__repr__.  Patch by iceboy.

   - bpo-26909(312): Fix slow pipes IO in asyncio.  Patch by INADA
     Naoki.

   - bpo-28176(313): Fix callbacks race in
     asyncio.SelectorLoop.sock_connect.

   - bpo-27759(314): Fix selectors incorrectly retain invalid file
     descriptors.  Patch by Mark Williams.

   - bpo-28325(315): Remove vestigial MacOS 9 macurl2path module and its
     tests.

   - bpo-28368(316): Refuse monitoring processes if the child watcher
     has no loop attached.  Patch by Vincent Michel.

   - bpo-28369(317): Raise RuntimeError when transport’s FD is used with
     add_reader, add_writer, etc.

   - bpo-28370(318): Speedup asyncio.StreamReader.readexactly.  Patch by
     Коренберг Марк.

   - bpo-28371(319): Deprecate passing asyncio.Handles to
     run_in_executor.

   - bpo-28372(320): Fix asyncio to support formatting of non-python
     coroutines.

   - bpo-28399(321): Remove UNIX socket from FS before binding.  Patch
     by Коренберг Марк.

   - bpo-27972(322): Prohibit Tasks to await on themselves.

   - bpo-24142(323): Reading a corrupt config file left configparser in
     an invalid state.  Original patch by Florian Höch.

   - bpo-29581(324): ABCMeta.__new__ now accepts ‘**kwargs’, allowing
     abstract base classes to use keyword parameters in
     __init_subclass__.  Patch by Nate Soares.

   - bpo-25532(325): inspect.unwrap() will now only try to unwrap an
     object sys.getrecursionlimit() times, to protect against objects
     which create a new object on every attribute access.

   - bpo-30177(326): path.resolve(strict=False) no longer cuts the path
     after the first element not present in the filesystem.  Patch by
     Antoine Pietri.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31499

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31482

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31544

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31234

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31431

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31233

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28638

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31400

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27629

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28958

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28182

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27340

   (16) https://bugs.python.org/issue?@action=redirect&bpo=14191

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31178

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31350

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31170

   (20) https://bugs.python.org/issue?@action=redirect&bpo=29136

   (21) https://bugs.python.org/issue?@action=redirect&bpo=1198569

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31326

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27144

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31281

   (25) https://bugs.python.org/issue?@action=redirect&bpo=10746

   (26) https://peps.python.org/pep-3118/

   (27) https://bugs.python.org/issue?@action=redirect&bpo=27584

   (28) https://bugs.python.org/issue?@action=redirect&bpo=22536

   (29) https://bugs.python.org/issue?@action=redirect&bpo=29741

   (30) https://bugs.python.org/issue?@action=redirect&bpo=31249

   (31) https://bugs.python.org/issue?@action=redirect&bpo=31247

   (32) https://bugs.python.org/issue?@action=redirect&bpo=23835

   (33) https://bugs.python.org/issue?@action=redirect&bpo=31238

   (34) https://bugs.python.org/issue?@action=redirect&bpo=5001

   (35) https://bugs.python.org/issue?@action=redirect&bpo=31109

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30102

   (37) https://bugs.python.org/issue?@action=redirect&bpo=18966

   (38) https://bugs.python.org/issue?@action=redirect&bpo=31183

   (39) https://bugs.python.org/issue?@action=redirect&bpo=5001

   (40) https://bugs.python.org/issue?@action=redirect&bpo=31185

   (41) https://bugs.python.org/issue?@action=redirect&bpo=31151

   (42) https://bugs.python.org/issue?@action=redirect&bpo=31072

   (43) https://bugs.python.org/issue?@action=redirect&bpo=24700

   (44) https://bugs.python.org/issue?@action=redirect&bpo=31135

   (45) https://bugs.python.org/issue?@action=redirect&bpo=31107

   (46) https://bugs.python.org/issue?@action=redirect&bpo=31080

   (47) https://bugs.python.org/issue?@action=redirect&bpo=30897

   (48) https://bugs.python.org/issue?@action=redirect&bpo=31061

   (49) https://bugs.python.org/issue?@action=redirect&bpo=30987

   (50) https://bugs.python.org/issue?@action=redirect&bpo=30522

   (51) https://bugs.python.org/issue?@action=redirect&bpo=30502

   (52) https://bugs.python.org/issue?@action=redirect&bpo=5288

   (53) https://bugs.python.org/issue?@action=redirect&bpo=30919

   (54) https://bugs.python.org/issue?@action=redirect&bpo=26732

   (55) https://bugs.python.org/issue?@action=redirect&bpo=29403

   (56) https://bugs.python.org/issue?@action=redirect&bpo=30961

   (57) https://bugs.python.org/issue?@action=redirect&bpo=19896

   (58) https://bugs.python.org/issue?@action=redirect&bpo=30946

   (59) https://bugs.python.org/issue?@action=redirect&bpo=25684

   (60) https://bugs.python.org/issue?@action=redirect&bpo=30886

   (61) https://bugs.python.org/issue?@action=redirect&bpo=29854

   (62) https://bugs.python.org/issue?@action=redirect&bpo=30794

   (63) https://bugs.python.org/issue?@action=redirect&bpo=30319

   (64) https://bugs.python.org/issue?@action=redirect&bpo=30828

   (65) https://bugs.python.org/issue?@action=redirect&bpo=30302

   (66) https://bugs.python.org/issue?@action=redirect&bpo=30807

   (67) https://bugs.python.org/issue?@action=redirect&bpo=30441

   (68) https://bugs.python.org/issue?@action=redirect&bpo=29585

   (69) https://bugs.python.org/issue?@action=redirect&bpo=29293

   (70) https://bugs.python.org/issue?@action=redirect&bpo=30532

   (71) https://bugs.python.org/issue?@action=redirect&bpo=30596

   (72) https://bugs.python.org/issue?@action=redirect&bpo=9146

   (73) https://bugs.python.org/issue?@action=redirect&bpo=29169

   (74) https://bugs.python.org/issue?@action=redirect&bpo=30119

   (75) https://bugs.python.org/issue?@action=redirect&bpo=30879

   (76) https://bugs.python.org/issue?@action=redirect&bpo=30746

   (77) https://bugs.python.org/issue?@action=redirect&bpo=30664

   (78) https://bugs.python.org/issue?@action=redirect&bpo=21071

   (79) https://bugs.python.org/issue?@action=redirect&bpo=29212

   (80) https://bugs.python.org/issue?@action=redirect&bpo=29755

   (81) https://bugs.python.org/issue?@action=redirect&bpo=30616

   (82) https://bugs.python.org/issue?@action=redirect&bpo=30038

   (83) https://bugs.python.org/issue?@action=redirect&bpo=23894

   (84) https://bugs.python.org/issue?@action=redirect&bpo=24744

   (85) https://bugs.python.org/issue?@action=redirect&bpo=24484

   (86) https://bugs.python.org/issue?@action=redirect&bpo=30589

   (87) https://bugs.python.org/issue?@action=redirect&bpo=28994

   (88) https://bugs.python.org/issue?@action=redirect&bpo=30508

   (89) https://bugs.python.org/issue?@action=redirect&bpo=30645

   (90) https://bugs.python.org/issue?@action=redirect&bpo=11822

   (91) https://bugs.python.org/issue?@action=redirect&bpo=30624

   (92) https://bugs.python.org/issue?@action=redirect&bpo=30595

   (93) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (94) https://bugs.python.org/issue?@action=redirect&bpo=30605

   (95) https://bugs.python.org/issue?@action=redirect&bpo=29870

   (96) https://bugs.python.org/issue?@action=redirect&bpo=29743

   (97) https://bugs.python.org/issue?@action=redirect&bpo=27585

   (98) https://bugs.python.org/issue?@action=redirect&bpo=30014

   (99) https://bugs.python.org/issue?@action=redirect&bpo=30418

   (100) https://bugs.python.org/issue?@action=redirect&bpo=30463

   (101) https://bugs.python.org/issue?@action=redirect&bpo=30520

   (102) https://bugs.python.org/issue?@action=redirect&bpo=30557

   (103) https://bugs.python.org/issue?@action=redirect&bpo=30526

   (104) https://bugs.python.org/issue?@action=redirect&bpo=30245

   (105) https://bugs.python.org/issue?@action=redirect&bpo=30378

   (106) https://bugs.python.org/issue?@action=redirect&bpo=16500

   (107) https://bugs.python.org/issue?@action=redirect&bpo=30470

   (108) https://bugs.python.org/issue?@action=redirect&bpo=30414

   (109) https://bugs.python.org/issue?@action=redirect&bpo=30003

   (110) https://bugs.python.org/issue?@action=redirect&bpo=30149

   (111) https://bugs.python.org/issue?@action=redirect&bpo=30436

   (112) https://bugs.python.org/issue?@action=redirect&bpo=30301

   (113) https://bugs.python.org/issue?@action=redirect&bpo=30375

   (114) https://bugs.python.org/issue?@action=redirect&bpo=30329

   (115) https://bugs.python.org/issue?@action=redirect&bpo=29196

   (116) https://bugs.python.org/issue?@action=redirect&bpo=9850

   (117) https://bugs.python.org/issue?@action=redirect&bpo=30299

   (118) https://bugs.python.org/issue?@action=redirect&bpo=30048

   (119) https://bugs.python.org/issue?@action=redirect&bpo=30266

   (120) https://bugs.python.org/issue?@action=redirect&bpo=25958

   (121) https://bugs.python.org/issue?@action=redirect&bpo=30340

   (122) https://bugs.python.org/issue?@action=redirect&bpo=30298

   (123) https://bugs.python.org/issue?@action=redirect&bpo=30285

   (124) https://bugs.python.org/issue?@action=redirect&bpo=29990

   (125) https://bugs.python.org/issue?@action=redirect&bpo=29979

   (126) https://bugs.python.org/issue?@action=redirect&bpo=30243

   (127) https://bugs.python.org/issue?@action=redirect&bpo=30215

   (128) https://bugs.python.org/issue?@action=redirect&bpo=30185

   (129) https://bugs.python.org/issue?@action=redirect&bpo=30103

   (130) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (131) https://bugs.python.org/issue?@action=redirect&bpo=30205

   (132) https://bugs.python.org/issue?@action=redirect&bpo=30228

   (133) https://bugs.python.org/issue?@action=redirect&bpo=30190

   (134) https://bugs.python.org/issue?@action=redirect&bpo=30101

   (135) https://bugs.python.org/issue?@action=redirect&bpo=29822

   (136) https://bugs.python.org/issue?@action=redirect&bpo=29960

   (137) https://bugs.python.org/issue?@action=redirect&bpo=30070

   (138) https://bugs.python.org/issue?@action=redirect&bpo=22352

   (139) https://bugs.python.org/issue?@action=redirect&bpo=30061

   (140) https://bugs.python.org/issue?@action=redirect&bpo=30218

   (141) https://bugs.python.org/issue?@action=redirect&bpo=10076

   (142) https://bugs.python.org/issue?@action=redirect&bpo=30068

   (143) https://bugs.python.org/issue?@action=redirect&bpo=29694

   (144) https://bugs.python.org/issue?@action=redirect&bpo=29692

   (145) https://bugs.python.org/issue?@action=redirect&bpo=26187

   (146) https://bugs.python.org/issue?@action=redirect&bpo=9303

   (147) https://bugs.python.org/issue?@action=redirect&bpo=30017

   (148) https://bugs.python.org/issue?@action=redirect&bpo=29998

   (149) https://bugs.python.org/issue?@action=redirect&bpo=29995

   (150) https://bugs.python.org/issue?@action=redirect&bpo=29962

   (151) https://bugs.python.org/issue?@action=redirect&bpo=29649

   (152) https://bugs.python.org/issue?@action=redirect&bpo=29654

   (153) https://bugs.python.org/issue?@action=redirect&bpo=29931

   (154) https://bugs.python.org/issue?@action=redirect&bpo=29953

   (155) https://bugs.python.org/issue?@action=redirect&bpo=29942

   (156) https://bugs.python.org/issue?@action=redirect&bpo=10030

   (157) https://bugs.python.org/issue?@action=redirect&bpo=29204

   (158) https://bugs.python.org/issue?@action=redirect&bpo=27863

   (159) https://bugs.python.org/issue?@action=redirect&bpo=25996

   (160) https://bugs.python.org/issue?@action=redirect&bpo=28699

   (161) https://bugs.python.org/issue?@action=redirect&bpo=23890

   (162) https://bugs.python.org/issue?@action=redirect&bpo=29901

   (163) https://bugs.python.org/issue?@action=redirect&bpo=25803

   (164) https://bugs.python.org/issue?@action=redirect&bpo=29861

   (165) https://bugs.python.org/issue?@action=redirect&bpo=19930

   (166) https://bugs.python.org/issue?@action=redirect&bpo=29884

   (167) https://bugs.python.org/issue?@action=redirect&bpo=25455

   (168) https://bugs.python.org/issue?@action=redirect&bpo=29800

   (169) https://bugs.python.org/issue?@action=redirect&bpo=8256

   (170) https://bugs.python.org/issue?@action=redirect&bpo=28692

   (171) https://bugs.python.org/issue?@action=redirect&bpo=26121

   (172) https://bugs.python.org/issue?@action=redirect&bpo=29619

   (173) https://bugs.python.org/issue?@action=redirect&bpo=28298

   (174) https://bugs.python.org/issue?@action=redirect&bpo=29645

   (175) https://bugs.python.org/issue?@action=redirect&bpo=28231

   (176) https://bugs.python.org/issue?@action=redirect&bpo=26915

   (177) https://bugs.python.org/issue?@action=redirect&bpo=28682

   (178) https://bugs.python.org/issue?@action=redirect&bpo=29728

   (179) https://bugs.python.org/issue?@action=redirect&bpo=29623

   (180) https://bugs.python.org/issue?@action=redirect&bpo=9303

   (181) https://bugs.python.org/issue?@action=redirect&bpo=28963

   (182) https://bugs.python.org/issue?@action=redirect&bpo=29704

   (183) https://bugs.python.org/issue?@action=redirect&bpo=29271

   (184) https://bugs.python.org/issue?@action=redirect&bpo=29703

   (185) https://bugs.python.org/issue?@action=redirect&bpo=29615

   (186) https://bugs.python.org/issue?@action=redirect&bpo=7769

   (187) https://bugs.python.org/issue?@action=redirect&bpo=29376

   (188) https://bugs.python.org/issue?@action=redirect&bpo=28624

   (189) https://bugs.python.org/issue?@action=redirect&bpo=28518

   (190) https://bugs.python.org/issue?@action=redirect&bpo=29742

   (191) https://bugs.python.org/issue?@action=redirect&bpo=16285

   (192) https://bugs.python.org/issue?@action=redirect&bpo=29532

   (193) https://bugs.python.org/issue?@action=redirect&bpo=29110

   (194) https://bugs.python.org/issue?@action=redirect&bpo=22807

   (195) https://bugs.python.org/issue?@action=redirect&bpo=29576

   (196) https://bugs.python.org/issue?@action=redirect&bpo=29534

   (197) https://bugs.python.org/issue?@action=redirect&bpo=10379

   (198) https://bugs.python.org/issue?@action=redirect&bpo=29851

   (199) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (200) https://bugs.python.org/issue?@action=redirect&bpo=29100

   (201) https://bugs.python.org/issue?@action=redirect&bpo=29416

   (202) https://bugs.python.org/issue?@action=redirect&bpo=29444

   (203) https://bugs.python.org/issue?@action=redirect&bpo=29377

   (204) https://bugs.python.org/issue?@action=redirect&bpo=29218

   (205) https://bugs.python.org/issue?@action=redirect&bpo=29368

   (206) https://bugs.python.org/issue?@action=redirect&bpo=29338

   (207) https://bugs.python.org/issue?@action=redirect&bpo=29335

   (208) https://bugs.python.org/issue?@action=redirect&bpo=29290

   (209) https://bugs.python.org/issue?@action=redirect&bpo=28735

   (210) https://bugs.python.org/issue?@action=redirect&bpo=29197

   (211) https://bugs.python.org/issue?@action=redirect&bpo=29210

   (212) https://bugs.python.org/issue?@action=redirect&bpo=29219

   (213) https://bugs.python.org/issue?@action=redirect&bpo=29192

   (214) https://bugs.python.org/issue?@action=redirect&bpo=29193

   (215) https://bugs.python.org/issue?@action=redirect&bpo=29195

   (216) https://bugs.python.org/issue?@action=redirect&bpo=28969

   (217) https://bugs.python.org/issue?@action=redirect&bpo=20804

   (218) https://bugs.python.org/issue?@action=redirect&bpo=29142

   (219) https://bugs.python.org/issue?@action=redirect&bpo=28961

   (220) https://bugs.python.org/issue?@action=redirect&bpo=15812

   (221) https://bugs.python.org/issue?@action=redirect&bpo=28985

   (222) https://bugs.python.org/issue?@action=redirect&bpo=29079

   (223) https://bugs.python.org/issue?@action=redirect&bpo=13051

   (224) https://bugs.python.org/issue?@action=redirect&bpo=9770

   (225) https://bugs.python.org/issue?@action=redirect&bpo=28427

   (226) https://bugs.python.org/issue?@action=redirect&bpo=28923

   (227) https://bugs.python.org/issue?@action=redirect&bpo=28871

   (228) https://bugs.python.org/issue?@action=redirect&bpo=19542

   (229) https://bugs.python.org/issue?@action=redirect&bpo=20191

   (230) https://bugs.python.org/issue?@action=redirect&bpo=16255

   (231) https://bugs.python.org/issue?@action=redirect&bpo=28779

   (232) https://bugs.python.org/issue?@action=redirect&bpo=26937

   (233) https://bugs.python.org/issue?@action=redirect&bpo=28847

   (234) https://bugs.python.org/issue?@action=redirect&bpo=27030

   (235) https://bugs.python.org/issue?@action=redirect&bpo=28835

   (236) https://bugs.python.org/issue?@action=redirect&bpo=27172

   (237) https://bugs.python.org/issue?@action=redirect&bpo=28740

   (238) https://bugs.python.org/issue?@action=redirect&bpo=26273

   (239) https://bugs.python.org/issue?@action=redirect&bpo=28752

   (240) https://bugs.python.org/issue?@action=redirect&bpo=28727

   (241) https://bugs.python.org/issue?@action=redirect&bpo=18383

   (242) https://bugs.python.org/issue?@action=redirect&bpo=20572

   (243) https://bugs.python.org/issue?@action=redirect&bpo=25659

   (244) https://bugs.python.org/issue?@action=redirect&bpo=28548

   (245) https://bugs.python.org/issue?@action=redirect&bpo=19717

   (246) https://bugs.python.org/issue?@action=redirect&bpo=28563

   (247) https://bugs.python.org/issue?@action=redirect&bpo=28387

   (248) https://bugs.python.org/issue?@action=redirect&bpo=27517

   (249) https://bugs.python.org/issue?@action=redirect&bpo=28549

   (250) https://bugs.python.org/issue?@action=redirect&bpo=28449

   (251) https://bugs.python.org/issue?@action=redirect&bpo=23262

   (252) https://bugs.python.org/issue?@action=redirect&bpo=24241

   (253) https://bugs.python.org/issue?@action=redirect&bpo=27939

   (254) https://bugs.python.org/issue?@action=redirect&bpo=28255

   (255) https://bugs.python.org/issue?@action=redirect&bpo=28255

   (256) https://bugs.python.org/issue?@action=redirect&bpo=20491

   (257) https://bugs.python.org/issue?@action=redirect&bpo=28353

   (258) https://bugs.python.org/issue?@action=redirect&bpo=28430

   (259) https://bugs.python.org/issue?@action=redirect&bpo=27025

   (260) https://bugs.python.org/issue?@action=redirect&bpo=25464

   (261) https://bugs.python.org/issue?@action=redirect&bpo=28488

   (262) https://bugs.python.org/issue?@action=redirect&bpo=25953

   (263) https://bugs.python.org/issue?@action=redirect&bpo=28469

   (264) https://bugs.python.org/issue?@action=redirect&bpo=28115

   (265) https://bugs.python.org/issue?@action=redirect&bpo=18219

   (266) https://bugs.python.org/issue?@action=redirect&bpo=28448

   (267) https://bugs.python.org/issue?@action=redirect&bpo=23214

   (268) https://bugs.python.org/issue?@action=redirect&bpo=28480

   (269) https://bugs.python.org/issue?@action=redirect&bpo=28240

   (270) https://bugs.python.org/issue?@action=redirect&bpo=28240

   (271) https://bugs.python.org/issue?@action=redirect&bpo=28240

   (272) https://github.com/pypa/setuptools/issues/100

   (273) https://bugs.python.org/issue?@action=redirect&bpo=24452

   (274) https://bugs.python.org/issue?@action=redirect&bpo=20766

   (275) https://bugs.python.org/issue?@action=redirect&bpo=27998

   (276) https://bugs.python.org/issue?@action=redirect&bpo=28317

   (277) https://bugs.python.org/issue?@action=redirect&bpo=28380

   (278) https://bugs.python.org/issue?@action=redirect&bpo=28229

   (279) https://bugs.python.org/issue?@action=redirect&bpo=28321

   (280) https://bugs.python.org/issue?@action=redirect&bpo=28225

   (281) https://bugs.python.org/issue?@action=redirect&bpo=28227

   (282) https://bugs.python.org/issue?@action=redirect&bpo=28332

   (283) https://bugs.python.org/issue?@action=redirect&bpo=27358

   (284) https://bugs.python.org/issue?@action=redirect&bpo=28257

   (285) https://bugs.python.org/issue?@action=redirect&bpo=28322

   (286) https://bugs.python.org/issue?@action=redirect&bpo=28228

   (287) https://bugs.python.org/issue?@action=redirect&bpo=28226

   (288) https://bugs.python.org/issue?@action=redirect&bpo=28314

   (289) https://bugs.python.org/issue?@action=redirect&bpo=28148

   (290) https://bugs.python.org/issue?@action=redirect&bpo=28253

   (291) https://bugs.python.org/issue?@action=redirect&bpo=28275

   (292) https://bugs.python.org/issue?@action=redirect&bpo=27897

   (293) https://bugs.python.org/issue?@action=redirect&bpo=18844

   (294) https://bugs.python.org/issue?@action=redirect&bpo=18893

   (295) https://bugs.python.org/issue?@action=redirect&bpo=27611

   (296) https://bugs.python.org/issue?@action=redirect&bpo=27348

   (297) https://bugs.python.org/issue?@action=redirect&bpo=25651

   (298) https://bugs.python.org/issue?@action=redirect&bpo=27778

   (299) https://bugs.python.org/issue?@action=redirect&bpo=28200

   (300) https://bugs.python.org/issue?@action=redirect&bpo=25400

   (301) https://bugs.python.org/issue?@action=redirect&bpo=27932

   (302) https://bugs.python.org/issue?@action=redirect&bpo=28075

   (303) https://bugs.python.org/issue?@action=redirect&bpo=22493

   (304) https://bugs.python.org/issue?@action=redirect&bpo=25270

   (305) https://bugs.python.org/issue?@action=redirect&bpo=28181

   (306) https://bugs.python.org/issue?@action=redirect&bpo=25895

   (307) https://bugs.python.org/issue?@action=redirect&bpo=28114

   (308) https://bugs.python.org/issue?@action=redirect&bpo=27599

   (309) https://bugs.python.org/issue?@action=redirect&bpo=27906

   (310) https://bugs.python.org/issue?@action=redirect&bpo=28174

   (311) https://bugs.python.org/issue?@action=redirect&bpo=26654

   (312) https://bugs.python.org/issue?@action=redirect&bpo=26909

   (313) https://bugs.python.org/issue?@action=redirect&bpo=28176

   (314) https://bugs.python.org/issue?@action=redirect&bpo=27759

   (315) https://bugs.python.org/issue?@action=redirect&bpo=28325

   (316) https://bugs.python.org/issue?@action=redirect&bpo=28368

   (317) https://bugs.python.org/issue?@action=redirect&bpo=28369

   (318) https://bugs.python.org/issue?@action=redirect&bpo=28370

   (319) https://bugs.python.org/issue?@action=redirect&bpo=28371

   (320) https://bugs.python.org/issue?@action=redirect&bpo=28372

   (321) https://bugs.python.org/issue?@action=redirect&bpo=28399

   (322) https://bugs.python.org/issue?@action=redirect&bpo=27972

   (323) https://bugs.python.org/issue?@action=redirect&bpo=24142

   (324) https://bugs.python.org/issue?@action=redirect&bpo=29581

   (325) https://bugs.python.org/issue?@action=redirect&bpo=25532

   (326) https://bugs.python.org/issue?@action=redirect&bpo=30177


File: python.info,  Node: Documentation<64>,  Next: Tests<64>,  Prev: Library<149>,  Up: Python 3 7 0 alpha 1

1.23.74.4 Documentation
.......................

   - bpo-31294(1): Fix incomplete code snippet in the
     ZeroMQSocketListener and ZeroMQSocketHandler examples and adapt
     them to Python 3.

   - bpo-21649(2): Add RFC 7525 and Mozilla server side TLS links to SSL
     documentation.

   - bpo-31128(3): Allow the pydoc server to bind to arbitrary
     hostnames.

   - bpo-30803(4): Clarify doc on truth value testing.  Original patch
     by Peter Thomassen.

   - bpo-30176(5): Add missing attribute related constants in curses
     documentation.

   - bpo-30052(6): the link targets for *note bytes(): 1c2. and *note
     bytearray(): 2ea. are now their respective type definitions, rather
     than the corresponding builtin function entries.  Use *note bytes:
     1c4b. and *note bytearray: 1c4c. to reference the latter.  In order
     to ensure this and future cross-reference updates are applied
     automatically, the daily documentation builds now disable the
     default output caching features in Sphinx.

   - bpo-26985(7): Add missing info of code object in inspect
     documentation.

   - bpo-19824(8): Improve the documentation for, and links to, template
     strings by emphasizing their utility for internationalization, and
     by clarifying some usage constraints.  (See also: bpo-20314(9),
     bpo-12518(10))

   - bpo-28929(11): Link the documentation to its source file on GitHub.

   - bpo-25008(12): Document smtpd.py as effectively deprecated and add
     a pointer to aiosmtpd, a third-party asyncio-based replacement.

   - bpo-26355(13): Add canonical header link on each page to
     corresponding major version of the documentation.  Patch by
     Matthias Bussonnier.

   - bpo-29349(14): Fix Python 2 syntax in code for building the
     documentation.

   - bpo-23722(15): The data model reference and the porting section in
     the 3.6 What’s New guide now cover the additional ‘__classcell__’
     handling needed for custom metaclasses to fully support PEP 487(16)
     and zero-argument ‘super()’.

   - bpo-28513(17): Documented command-line interface of zipfile.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31294

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31128

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30803

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30176

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30052

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26985

   (8) https://bugs.python.org/issue?@action=redirect&bpo=19824

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20314

   (10) https://bugs.python.org/issue?@action=redirect&bpo=12518

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28929

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25008

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26355

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29349

   (15) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (16) https://peps.python.org/pep-0487/

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28513


File: python.info,  Node: Tests<64>,  Next: Build<69>,  Prev: Documentation<64>,  Up: Python 3 7 0 alpha 1

1.23.74.5 Tests
...............

   - bpo-29639(1): test.support.HOST is now “localhost”, a new HOSTv4
     constant has been added for your ‘127.0.0.1’ needs, similar to the
     existing HOSTv6 constant.

   - bpo-31320(2): Silence traceback in test_ssl

   - bpo-31346(3): Prefer PROTOCOL_TLS_CLIENT and PROTOCOL_TLS_SERVER
     protocols for SSLContext.

   - bpo-25674(4): Remove sha256.tbs-internet.com ssl test

   - bpo-30715(5): Address ALPN callback changes for OpenSSL 1.1.0f.
     The latest version behaves like OpenSSL 1.0.2 and no longer aborts
     handshake.

   - bpo-30822(6): regrtest: Exclude tzdata from regrtest –all.  When
     running the test suite using –use=all / -u all, exclude tzdata
     since it makes test_datetime too slow (15-20 min on some buildbots)
     which then times out on some buildbots.  Fix also regrtest command
     line parser to allow passing -u extralargefile to run
     test_zipfile64.

   - bpo-30695(7): Add the ‘set_nomemory(start, stop)’ and
     ‘remove_mem_hooks()’ functions to the ‘_testcapi’ module.

   - bpo-30357(8): test_thread: setUp() now uses
     support.threading_setup() and support.threading_cleanup() to wait
     until threads complete to avoid random side effects on following
     tests.  Initial patch written by Grzegorz Grzywacz.

   - bpo-30197(9): Enhanced functions swap_attr() and swap_item() in the
     test.support module.  They now work when delete replaced attribute
     or item inside the with statement.  The old value of the attribute
     or item (or None if it doesn’t exist) now will be assigned to the
     target of the “as” clause, if there is one.

   - bpo-24932(10): Use proper command line parsing in _testembed

   - bpo-28950(11): Disallow -j0 to be combined with -T/-l in regrtest
     command line arguments.

   - bpo-28683(12): Fix the tests that bind() a unix socket and raise
     PermissionError on Android for a non-root user.

   - bpo-26936(13): Fix the test_socket failures on Android -
     getservbyname(), getservbyport() and getaddrinfo() are broken on
     some Android API levels.

   - bpo-28666(14): Now test.support.rmtree is able to remove unwritable
     or unreadable directories.

   - bpo-23839(15): Various caches now are cleared before running every
     test file.

   - bpo-26944(16): Fix test_posix for Android where ‘id -G’ is entirely
     wrong or missing the effective gid.

   - bpo-28409(17): regrtest: fix the parser of command line arguments.

   - bpo-28217(18): Adds _testconsole module to test console input.

   - bpo-26939(19): Add the support.setswitchinterval() function to fix
     test_functools hanging on the Android armv7 qemu emulator.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29639

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31320

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31346

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25674

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30715

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30822

   (7) https://bugs.python.org/issue?@action=redirect&bpo=30695

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30357

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30197

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24932

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28950

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28683

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26936

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28666

   (15) https://bugs.python.org/issue?@action=redirect&bpo=23839

   (16) https://bugs.python.org/issue?@action=redirect&bpo=26944

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28409

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28217

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26939


File: python.info,  Node: Build<69>,  Next: Windows<61>,  Prev: Tests<64>,  Up: Python 3 7 0 alpha 1

1.23.74.6 Build
...............

   - bpo-31354(1): Allow ‘--with-lto’ to be used on all builds, not just
     ‘make profile-opt’.

   - bpo-31370(2): Remove support for building –without-threads.  This
     option is not really useful anymore in the 21st century.  Removing
     lots of conditional paths allows us to simplify the code base,
     including in difficult to maintain low-level internal code.

   - bpo-31341(3): Per PEP 11(4), support for the IRIX operating system
     was removed.

   - bpo-30854(5): Fix compile error when compiling –without-threads.
     Patch by Masayuki Yamamoto.

   - bpo-30687(6): Locate msbuild.exe on Windows when building rather
     than vcvarsall.bat

   - bpo-20210(7): Support the 'disabled' marker in Setup files.
     Extension modules listed after this marker are not built at all,
     neither by the Makefile nor by setup.py.

   - bpo-29941(8): Add ‘--with-assertions’ configure flag to explicitly
     enable C ‘assert()’ checks.  Defaults to off.  ‘--with-pydebug’
     implies ‘--with-assertions’.

   - bpo-28787(9): Fix out-of-tree builds of Python when configured with
     ‘--with--dtrace’.

   - bpo-29243(10): Prevent unnecessary rebuilding of Python during
     ‘make test’, ‘make install’ and some other make targets when
     configured with ‘--enable-optimizations’.

   - bpo-23404(11): Don’t regenerate generated files based on file
     modification time anymore: the action is now explicit.  Replace
     ‘make touch’ with ‘make regen-all’.

   - bpo-29643(12): Fix ‘--enable-optimization’ didn’t work.

   - bpo-27593(13): sys.version and the platform module python_build(),
     python_branch(), and python_revision() functions now use git
     information rather than hg when building from a repo.

   - bpo-29572(14): Update Windows build and OS X installers to use
     OpenSSL 1.0.2k.

   - bpo-27659(15): Prohibit implicit C function declarations: use
     ‘-Werror=implicit-function-declaration’ when possible (GCC and
     Clang, but it depends on the compiler version).  Patch written by
     Chi Hsuan Yen.

   - bpo-29384(16): Remove old Be OS helper scripts.

   - bpo-26851(17): Set Android compilation and link flags.

   - bpo-28768(18): Fix implicit declaration of function _setmode.
     Patch by Masayuki Yamamoto

   - bpo-29080(19): Removes hard dependency on hg.exe from
     PCBuild/build.bat

   - bpo-23903(20): Added missed names to PC/python3.def.

   - bpo-28762(21): lockf() is available on Android API level 24, but
     the F_LOCK macro is not defined in android-ndk-r13.

   - bpo-28538(22): Fix the compilation error that occurs because
     if_nameindex() is available on Android API level 24, but the
     if_nameindex structure is not defined.

   - bpo-20211(23): Do not add the directory for installing C header
     files and the directory for installing object code libraries to the
     cross compilation search paths.  Original patch by Thomas
     Petazzoni.

   - bpo-28849(24): Do not define sys.implementation._multiarch on
     Android.

   - bpo-10656(25): Fix out-of-tree building on AIX. Patch by Tristan
     Carel and Michael Haubenwallner.

   - bpo-26359(26): Rename –with-optimiations to –enable-optimizations.

   - bpo-28444(27): Fix missing extensions modules when cross compiling.

   - bpo-28208(28): Update Windows build and OS X installers to use
     SQLite 3.14.2.

   - bpo-28248(29): Update Windows build and OS X installers to use
     OpenSSL 1.0.2j.

   - bpo-21124(30): Fix building the _struct module on Cygwin by passing
     ‘NULL’ instead of ‘&PyType_Type’ to PyVarObject_HEAD_INIT. Patch by
     Masayuki Yamamoto.

   - bpo-13756(31): Fix building extensions modules on Cygwin.  Patch by
     Roumen Petrov, based on original patch by Jason Tishler.

   - bpo-21085(32): Add configure check for siginfo_t.si_band, which
     Cygwin does not provide.  Patch by Masayuki Yamamoto with review
     and rebase by Erik Bray.

   - bpo-28258(33): Fixed build with Estonian locale (python-config and
     distclean targets in Makefile).  Patch by Arfrever Frehtes
     Taifersar Arahesis.

   - bpo-26661(34): setup.py now detects system libffi with multiarch
     wrapper.

   - bpo-27979(35): A full copy of libffi is no longer bundled for use
     when building _ctypes on non-OSX UNIX platforms.  An installed copy
     of libffi is now required when building _ctypes on such platforms.

   - bpo-15819(36): Remove redundant include search directory option for
     building outside the source tree.

   - bpo-28676(37): Prevent missing ‘getentropy’ declaration warning on
     macOS. Patch by Gareth Rees.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31354

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31370

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31341

   (4) https://peps.python.org/pep-0011/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30854

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30687

   (7) https://bugs.python.org/issue?@action=redirect&bpo=20210

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29941

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28787

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29243

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23404

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29643

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27593

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29572

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27659

   (16) https://bugs.python.org/issue?@action=redirect&bpo=29384

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26851

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28768

   (19) https://bugs.python.org/issue?@action=redirect&bpo=29080

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23903

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28762

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28538

   (23) https://bugs.python.org/issue?@action=redirect&bpo=20211

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28849

   (25) https://bugs.python.org/issue?@action=redirect&bpo=10656

   (26) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28444

   (28) https://bugs.python.org/issue?@action=redirect&bpo=28208

   (29) https://bugs.python.org/issue?@action=redirect&bpo=28248

   (30) https://bugs.python.org/issue?@action=redirect&bpo=21124

   (31) https://bugs.python.org/issue?@action=redirect&bpo=13756

   (32) https://bugs.python.org/issue?@action=redirect&bpo=21085

   (33) https://bugs.python.org/issue?@action=redirect&bpo=28258

   (34) https://bugs.python.org/issue?@action=redirect&bpo=26661

   (35) https://bugs.python.org/issue?@action=redirect&bpo=27979

   (36) https://bugs.python.org/issue?@action=redirect&bpo=15819

   (37) https://bugs.python.org/issue?@action=redirect&bpo=28676


File: python.info,  Node: Windows<61>,  Next: IDLE<49>,  Prev: Build<69>,  Up: Python 3 7 0 alpha 1

1.23.74.7 Windows
.................

   - bpo-31392(1): Update Windows build to use OpenSSL 1.1.0f

   - bpo-30389(2): Adds detection of Visual Studio 2017 to distutils on
     Windows.

   - bpo-31358(3): zlib is no longer bundled in the CPython source,
     instead it is downloaded on demand just like bz2, lzma, OpenSSL,
     Tcl/Tk, and SQLite.

   - bpo-31340(4): Change to building with MSVC v141 (included with
     Visual Studio 2017)

   - bpo-30581(5): os.cpu_count() now returns the correct number of
     processors on Windows when the number of logical processors is
     greater than 64.

   - bpo-30916(6): Pre-build OpenSSL, Tcl and Tk and include the
     binaries in the build.

   - bpo-30731(7): Add a missing xmlns to python.manifest so that it
     matches the schema.

   - bpo-30291(8): Allow requiring 64-bit interpreters from py.exe using
     -64 suffix.  Contributed by Steve (Gadget) Barnes.

   - bpo-30362(9): Adds list options (-0, -0p) to py.exe launcher.
     Contributed by Steve Barnes.

   - bpo-23451(10): Fix socket deprecation warnings in socketmodule.c.
     Patch by Segev Finer.

   - bpo-30450(11): The build process on Windows no longer depends on
     Subversion, instead pulling external code from GitHub via a Python
     script.  If Python 3.6 is not found on the system (via ‘py -3.6’),
     NuGet is used to download a copy of 32-bit Python.

   - bpo-29579(12): Removes readme.txt from the installer.

   - bpo-25778(13): winreg does not truncate string correctly (Patch by
     Eryk Sun)

   - bpo-28896(14): Deprecate WindowsRegistryFinder and disable it by
     default

   - bpo-28522(15): Fixes mishandled buffer reallocation in getpathp.c

   - bpo-28402(16): Adds signed catalog files for stdlib on Windows.

   - bpo-28333(17): Enables Unicode for ps1/ps2 and input() prompts.
     (Patch by Eryk Sun)

   - bpo-28251(18): Improvements to help manuals on Windows.

   - bpo-28110(19): launcher.msi has different product codes between
     32-bit and 64-bit

   - bpo-28161(20): Opening CON for write access fails

   - bpo-28162(21): WindowsConsoleIO readall() fails if first line
     starts with Ctrl+Z

   - bpo-28163(22): WindowsConsoleIO fileno() passes wrong flags to
     _open_osfhandle

   - bpo-28164(23): _PyIO_get_console_type fails for various paths

   - bpo-28137(24): Renames Windows path file to ._pth

   - bpo-28138(25): Windows ._pth file should allow import site

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31392

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30389

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31358

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31340

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30581

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30916

   (7) https://bugs.python.org/issue?@action=redirect&bpo=30731

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30291

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30362

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23451

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30450

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29579

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25778

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28896

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28522

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28402

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28333

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28251

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28110

   (20) https://bugs.python.org/issue?@action=redirect&bpo=28161

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28162

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28163

   (23) https://bugs.python.org/issue?@action=redirect&bpo=28164

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28137

   (25) https://bugs.python.org/issue?@action=redirect&bpo=28138


File: python.info,  Node: IDLE<49>,  Next: Tools/Demos<36>,  Prev: Windows<61>,  Up: Python 3 7 0 alpha 1

1.23.74.8 IDLE
..............

   - bpo-31493(1): IDLE code context – fix code update and font update
     timers.  Canceling timers prevents a warning message when test_idle
     completes.

   - bpo-31488(2): IDLE - Update non-key options in former extension
     classes.  When applying configdialog changes, call .reload for each
     feature class.  Change ParenMatch so updated options affect
     existing instances attached to existing editor windows.

   - bpo-31477(3): IDLE - Improve rstrip entry in doc.  Strip trailing
     whitespace strips more than blank spaces.  Multiline string
     literals are not skipped.

   - bpo-31480(4): IDLE - make tests pass with zzdummy extension
     disabled by default.

   - bpo-31421(5): Document how IDLE runs tkinter programs.  IDLE calls
     tcl/tk update in the background in order to make live interaction
     and experimentation with tkinter applications much easier.

   - bpo-31414(6): IDLE – fix tk entry box tests by deleting first.
     Adding to an int entry is not the same as deleting and inserting
     because int(‘’) will fail.

   - bpo-31051(7): Rearrange IDLE configdialog GenPage into Window,
     Editor, and Help sections.

   - bpo-30617(8): IDLE - Add docstrings and tests for outwin subclass
     of editor.  Move some data and functions from the class to module
     level.  Patch by Cheryl Sabella.

   - bpo-31287(9): IDLE - Do not modify tkinter.message in
     test_configdialog.

   - bpo-27099(10): Convert IDLE’s built-in ‘extensions’ to regular
     features.  About 10 IDLE features were implemented as supposedly
     optional extensions.  Their different behavior could be confusing
     or worse for users and not good for maintenance.  Hence the
     conversion.  The main difference for users is that user
     configurable key bindings for builtin features are now handled
     uniformly.  Now, editing a binding in a keyset only affects its
     value in the keyset.  All bindings are defined together in the
     system-specific default keysets in config-extensions.def.  All
     custom keysets are saved as a whole in config-extension.cfg.  All
     take effect as soon as one clicks Apply or Ok.  The affected events
     are ‘<<force-open-completions>>’, ‘<<expand-word>>’,
     ‘<<force-open-calltip>>’, ‘<<flash-paren>>’,
     ‘<<format-paragraph>>’, ‘<<run-module>>’, ‘<<check-module>>’, and
     ‘<<zoom-height>>’.  Any (global) customizations made before 3.6.3
     will not affect their keyset-specific customization after 3.6.3.
     and vice versa.  Initial patch by Charles Wohlganger.

   - bpo-31206(11): IDLE: Factor HighPage(Frame) class from
     ConfigDialog.  Patch by Cheryl Sabella.

   - bpo-31001(12): Add tests for configdialog highlight tab.  Patch by
     Cheryl Sabella.

   - bpo-31205(13): IDLE: Factor KeysPage(Frame) class from
     ConfigDialog.  The slightly modified tests continue to pass.  Patch
     by Cheryl Sabella.

   - bpo-31130(14): IDLE – stop leaks in test_configdialog.  Initial
     patch by Victor Stinner.

   - bpo-31002(15): Add tests for configdialog keys tab.  Patch by
     Cheryl Sabella.

   - bpo-19903(16): IDLE: Calltips use ‘inspect.signature’ instead of
     ‘inspect.getfullargspec’.  This improves calltips for builtins
     converted to use Argument Clinic.  Patch by Louie Lu.

   - bpo-31083(17): IDLE - Add an outline of a TabPage class in
     configdialog.  Update existing classes to match outline.  Initial
     patch by Cheryl Sabella.

   - bpo-31050(18): Factor GenPage(Frame) class from ConfigDialog.  The
     slightly modified tests continue to pass.  Patch by Cheryl Sabella.

   - bpo-31004(19): IDLE - Factor FontPage(Frame) class from
     ConfigDialog.  Slightly modified tests continue to pass.  Fix
     General tests.  Patch mostly by Cheryl Sabella.

   - bpo-30781(20): IDLE - Use ttk widgets in ConfigDialog.  Patches by
     Terry Jan Reedy and Cheryl Sabella.

   - bpo-31060(21): IDLE - Finish rearranging methods of ConfigDialog
     Grouping methods pertaining to each tab and the buttons will aid
     writing tests and improving the tabs and will enable splitting the
     groups into classes.

   - bpo-30853(22): IDLE – Factor a VarTrace class out of ConfigDialog.
     Instance tracers manages pairs consisting of a tk variable and a
     callback function.  When tracing is turned on, setting the variable
     calls the function.  Test coverage for the new class is 100%.

   - bpo-31003(23): IDLE: Add more tests for General tab.

   - bpo-30993(24): IDLE - Improve configdialog font page and tests.  In
     configdialog: Document causal pathways in create_font_tab
     docstring.  Simplify some attribute names.  Move set_samples calls
     to var_changed_font (idea from Cheryl Sabella).  Move related
     functions to positions after the create widgets function.  In
     test_configdialog: Fix test_font_set so not order dependent.  Fix
     renamed test_indent_scale so it tests the widget.  Adjust tests for
     movement of set_samples call.  Add tests for load functions.  Put
     all font tests in one class and tab indent tests in another.
     Except for two lines, these tests completely cover the related
     functions.

   - bpo-30981(25): IDLE – Add more configdialog font page tests.

   - bpo-28523(26): IDLE: replace ‘colour’ with ‘color’ in configdialog.

   - bpo-30917(27): Add tests for idlelib.config.IdleConf.  Increase
     coverage from 46% to 96%.  Patch by Louie Lu.

   - bpo-30934(28): Document coverage details for idlelib tests.  Add
     section to idlelib/idle-test/README.txt.  Include check that
     branches are taken both ways.  Exclude IDLE-specific code that does
     not run during unit tests.

   - bpo-30913(29): IDLE: Document ConfigDialog tk Vars, methods, and
     widgets in docstrings This will facilitate improving the dialog and
     splitting up the class.  Original patch by Cheryl Sabella.

   - bpo-30899(30): IDLE: Add tests for ConfigParser subclasses in
     config.  Patch by Louie Lu.

   - bpo-30881(31): IDLE: Add docstrings to browser.py.  Patch by Cheryl
     Sabella.

   - bpo-30851(32): IDLE: Remove unused variables in configdialog.  One
     is a duplicate, one is set but cannot be altered by users.  Patch
     by Cheryl Sabella.

   - bpo-30870(33): IDLE: In Settings dialog, select font with Up, Down
     keys as well as mouse.  Initial patch by Louie Lu.

   - bpo-8231(34): IDLE: call config.IdleConf.GetUserCfgDir only once.

   - bpo-30779(35): IDLE: Factor ConfigChanges class from configdialog,
     put in config; test.  * In config, put dump test code in a
     function; run it and unittest in ‘if __name__ == ‘__main__’.  * Add
     class config.ConfigChanges based on changes_class_v4.py on bpo
     issue.  * Add class test_config.ChangesTest, partly using
     configdialog_tests_v1.py.  * Revise configdialog to use
     ConfigChanges; see tracker msg297804.  * Revise test_configdialog
     to match configdialog changes.  * Remove configdialog functions
     unused or moved to ConfigChanges.  Cheryl Sabella contributed parts
     of the patch.

   - bpo-30777(36): IDLE: configdialog - Add docstrings and fix
     comments.  Patch by Cheryl Sabella.

   - bpo-30495(37): IDLE: Improve textview with docstrings, PEP8 names,
     and more tests.  Patch by Cheryl Sabella.

   - bpo-30723(38): IDLE: Make several improvements to parenmatch.  Add
     ‘parens’ style to highlight both opener and closer.  Make ‘default’
     style, which is not default, a synonym for ‘opener’.  Make
     time-delay work the same with all styles.  Add help for config
     dialog extensions tab, including help for parenmatch.  Add new
     tests.  Original patch by Charles Wohlganger.

   - bpo-30674(39): IDLE: add docstrings to grep module.  Patch by
     Cheryl Sabella

   - bpo-21519(40): IDLE’s basic custom key entry dialog now detects
     duplicates properly.  Original patch by Saimadhav Heblikar.

   - bpo-29910(41): IDLE no longer deletes a character after commenting
     out a region by a key shortcut.  Add ‘return 'break'’ for this and
     other potential conflicts between IDLE and default key bindings.

   - bpo-30728(42): Review and change idlelib.configdialog names.
     Lowercase method and attribute names.  Replace ‘colour’ with
     ‘color’, expand overly cryptic names, delete unneeded underscores.
     Replace ‘import *’ with specific imports.  Patches by Cheryl
     Sabella.

   - bpo-6739(43): IDLE: Verify user-entered key sequences by trying to
     bind them with tk.  Add tests for all 3 validation functions.
     Original patch by G Polo.  Tests added by Cheryl Sabella.

   - bpo-15786(44): Fix several problems with IDLE’s autocompletion box.
     The following should now work: clicking on selection box items;
     using the scrollbar; selecting an item by hitting Return.  Hangs on
     MacOSX should no longer happen.  Patch by Louie Lu.

   - bpo-25514(45): Add doc subsubsection about IDLE failure to start.
     Popup no-connection message directs users to this section.

   - bpo-30642(46): Fix reference leaks in IDLE tests.  Patches by Louie
     Lu and Terry Jan Reedy.

   - bpo-30495(47): Add docstrings for textview.py and use PEP8 names.
     Patches by Cheryl Sabella and Terry Jan Reedy.

   - bpo-30290(48): Help-about: use pep8 names and add tests.  Increase
     coverage to 100%.  Patches by Louie Lu, Cheryl Sabella, and Terry
     Jan Reedy.

   - bpo-30303(49): Add _utest option to textview; add new tests.
     Increase coverage to 100%.  Patches by Louie Lu and Terry Jan
     Reedy.

   - bpo-29071(50): IDLE colors f-string prefixes (but not invalid ur
     prefixes).

   - bpo-28572(51): Add 10% to coverage of IDLE’s test_configdialog.
     Update and augment description of the configuration system.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31493

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31488

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31477

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31480

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31421

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31414

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31051

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30617

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31287

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27099

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31206

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31001

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31205

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31130

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31002

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19903

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31083

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31050

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31004

   (20) https://bugs.python.org/issue?@action=redirect&bpo=30781

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31060

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30853

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31003

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30993

   (25) https://bugs.python.org/issue?@action=redirect&bpo=30981

   (26) https://bugs.python.org/issue?@action=redirect&bpo=28523

   (27) https://bugs.python.org/issue?@action=redirect&bpo=30917

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30934

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30913

   (30) https://bugs.python.org/issue?@action=redirect&bpo=30899

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30881

   (32) https://bugs.python.org/issue?@action=redirect&bpo=30851

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30870

   (34) https://bugs.python.org/issue?@action=redirect&bpo=8231

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30779

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30777

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30495

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30723

   (39) https://bugs.python.org/issue?@action=redirect&bpo=30674

   (40) https://bugs.python.org/issue?@action=redirect&bpo=21519

   (41) https://bugs.python.org/issue?@action=redirect&bpo=29910

   (42) https://bugs.python.org/issue?@action=redirect&bpo=30728

   (43) https://bugs.python.org/issue?@action=redirect&bpo=6739

   (44) https://bugs.python.org/issue?@action=redirect&bpo=15786

   (45) https://bugs.python.org/issue?@action=redirect&bpo=25514

   (46) https://bugs.python.org/issue?@action=redirect&bpo=30642

   (47) https://bugs.python.org/issue?@action=redirect&bpo=30495

   (48) https://bugs.python.org/issue?@action=redirect&bpo=30290

   (49) https://bugs.python.org/issue?@action=redirect&bpo=30303

   (50) https://bugs.python.org/issue?@action=redirect&bpo=29071

   (51) https://bugs.python.org/issue?@action=redirect&bpo=28572


File: python.info,  Node: Tools/Demos<36>,  Next: C API<62>,  Prev: IDLE<49>,  Up: Python 3 7 0 alpha 1

1.23.74.9 Tools/Demos
.....................

   - bpo-30983(1): gdb integration commands (py-bt, etc.)  work on
     optimized shared builds now, too.  PEP 523(2) introduced
     _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on
     non-debug shared builds.  This broke the ability to use py-bt,
     py-up, and a few other Python-specific gdb integrations.  The
     problem is fixed by only looking for _PyEval_EvalFrameDefault
     frames in python-gdb.py.  Original patch by Bruno “Polaco”
     Penteado.

   - bpo-29748(3): Added the slice index converter in Argument Clinic.

   - bpo-24037(4): Argument Clinic now uses the converter
     ‘bool(accept={int})’ rather than ‘int’ for semantical booleans.
     This avoids repeating the default value for Python and C and will
     help in converting to ‘bool’ in future.

   - bpo-29367(5): python-gdb.py now supports also ‘method-wrapper’
     (‘wrapperobject’) objects.

   - bpo-28023(6): Fix python-gdb.py didn’t support new dict
     implementation.

   - bpo-15369(7): The pybench and pystone microbenchmark have been
     removed from Tools.  Please use the new Python benchmark suite
     ‘https://github.com/python/pyperformance’ which is more reliable
     and includes a portable version of pybench working on Python 2 and
     Python 3.

   - bpo-28102(8): The zipfile module CLI now prints usage to stderr.
     Patch by Stephen J. Turnbull.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30983

   (2) https://peps.python.org/pep-0523/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29748

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24037

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29367

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28023

   (7) https://bugs.python.org/issue?@action=redirect&bpo=15369

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28102


File: python.info,  Node: C API<62>,  Prev: Tools/Demos<36>,  Up: Python 3 7 0 alpha 1

1.23.74.10 C API
................

   - bpo-31338(1): Added the ‘Py_UNREACHABLE()’ macro for code paths
     which are never expected to be reached.  This and a few other
     useful macros are now documented in the C API manual.

   - bpo-30832(2): Remove own implementation for thread-local storage.
     CPython has provided the own implementation for thread-local
     storage (TLS) on Python/thread.c, it’s used in the case which a
     platform has not supplied native TLS. However, currently all
     supported platforms (Windows and pthreads) have provided native TLS
     and defined the Py_HAVE_NATIVE_TLS macro with unconditional in any
     case.

   - bpo-30708(3): PyUnicode_AsWideCharString() now raises a ValueError
     if the second argument is NULL and the wchar_t* string contains
     null characters.

   - bpo-16500(4): Deprecate PyOS_AfterFork() and add PyOS_BeforeFork(),
     PyOS_AfterFork_Parent() and PyOS_AfterFork_Child().

   - bpo-6532(5): The type of results of PyThread_start_new_thread() and
     PyThread_get_thread_ident(), and the id parameter of
     PyThreadState_SetAsyncExc() changed from “long” to “unsigned long”.

   - bpo-27867(6): Function PySlice_GetIndicesEx() is deprecated and
     replaced with a macro if Py_LIMITED_API is not set or set to the
     value between 0x03050400 and 0x03060000 (not including) or
     0x03060100 or higher.  Added functions PySlice_Unpack() and
     PySlice_AdjustIndices().

   - bpo-29083(7): Fixed the declaration of some public API functions.
     PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
     available in limited API. PyArg_ValidateKeywordArguments(),
     PyArg_UnpackTuple() and Py_BuildValue() were not available in
     limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

   - bpo-28769(8): The result of PyUnicode_AsUTF8AndSize() and
     PyUnicode_AsUTF8() is now of type ‘const char *’ rather of ‘char
     *’.

   - bpo-29058(9): All stable API extensions added after Python 3.2 are
     now available only when Py_LIMITED_API is set to the PY_VERSION_HEX
     value of the minimum Python version supporting this API.

   - bpo-28822(10): The index parameters 'start' and 'end' of
     PyUnicode_FindChar() are now adjusted to behave like
     ‘str[start:end]’.

   - bpo-28808(11): PyUnicode_CompareWithASCIIString() now never raises
     exceptions.

   - bpo-28761(12): The fields name and doc of structures PyMemberDef,
     PyGetSetDef, PyStructSequence_Field, PyStructSequence_Desc, and
     wrapperbase are now of type ‘const char *’ rather of ‘char *’.

   - bpo-28748(13): Private variable _Py_PackageContext is now of type
     ‘const char *’ rather of ‘char *’.

   - bpo-19569(14): Compiler warnings are now emitted if use most of
     deprecated functions.

   - bpo-28426(15): Deprecated undocumented functions
     PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(),
     PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31338

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30832

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30708

   (4) https://bugs.python.org/issue?@action=redirect&bpo=16500

   (5) https://bugs.python.org/issue?@action=redirect&bpo=6532

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27867

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29083

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28769

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29058

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28822

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28808

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28761

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28748

   (14) https://bugs.python.org/issue?@action=redirect&bpo=19569

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28426


File: python.info,  Node: Python 3 6 6 final,  Next: Python 3 6 6 release candidate 1,  Prev: Python 3 7 0 alpha 1,  Up: Changelog

1.23.75 Python 3.6.6 final
--------------------------

'Release date: 2018-06-27'

There were no new changes in version 3.6.6.


File: python.info,  Node: Python 3 6 6 release candidate 1,  Next: Python 3 6 5 final,  Prev: Python 3 6 6 final,  Up: Changelog

1.23.76 Python 3.6.6 release candidate 1
----------------------------------------

'Release date: 2018-06-11'

* Menu:

* Core and Builtins: Core and Builtins<147>.
* Library: Library<150>.
* Documentation: Documentation<65>.
* Tests: Tests<65>.
* Build: Build<70>.
* Windows: Windows<62>.
* macOS: macOS<49>.
* IDLE: IDLE<50>.
* Tools/Demos: Tools/Demos<37>.
* C API: C API<63>.


File: python.info,  Node: Core and Builtins<147>,  Next: Library<150>,  Up: Python 3 6 6 release candidate 1

1.23.76.1 Core and Builtins
...........................

   - bpo-33786(1): Fix asynchronous generators to handle GeneratorExit
     in athrow() correctly

   - bpo-30654(2): Fixed reset of the SIGINT handler to SIG_DFL on
     interpreter shutdown even when there was a custom handler set
     previously.  Patch by Philipp Kerling.

   - bpo-33622(3): Fixed a leak when the garbage collector fails to add
     an object with the ‘__del__’ method or referenced by it into the
     *note gc.garbage: 1206. list.  *note PyGC_Collect(): 998. can now
     be called when an exception is set and preserves it.

   - bpo-31849(4): Fix signed/unsigned comparison warning in pyhash.c.

   - bpo-33391(5): Fix a leak in set_symmetric_difference().

   - bpo-28055(6): Fix unaligned accesses in siphash24().  Patch by Rolf
     Eike Beer.

   - bpo-33231(7): Fix potential memory leak in ‘normalizestring()’.

   - bpo-29922(8): Improved error messages in ‘async with’ when
     ‘__aenter__()’ or ‘__aexit__()’ return non-awaitable object.

   - bpo-33199(9): Fix ‘ma_version_tag’ in dict implementation is
     uninitialized when copying from key-sharing dict.

   - bpo-33041(10): Fixed jumping when the function contains an ‘async
     for’ loop.

   - bpo-32282(11): Fix an unnecessary ifdef in the include of
     VersionHelpers.h in socketmodule on Windows.

   - bpo-21983(12): Fix a crash in ‘ctypes.cast()’ in case the type
     argument is a ctypes structured data type.  Patch by Eryk Sun and
     Oren Milman.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33786

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30654

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33622

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31849

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33391

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28055

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33231

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29922

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33199

   (10) https://bugs.python.org/issue?@action=redirect&bpo=33041

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32282

   (12) https://bugs.python.org/issue?@action=redirect&bpo=21983


File: python.info,  Node: Library<150>,  Next: Documentation<65>,  Prev: Core and Builtins<147>,  Up: Python 3 6 6 release candidate 1

1.23.76.2 Library
.................

   - bpo-30167(1): Prevent site.main() exception if PYTHONSTARTUP is
     set.  Patch by Steve Weber.

   - bpo-33812(2): Datetime instance d with non-None tzinfo, but with
     d.tzinfo.utcoffset(d) returning None is now treated as naive by the
     astimezone() method.

   - bpo-30805(3): Avoid race condition with debug logging

   - bpo-33767(4): The concatenation (‘+’) and repetition (‘*’) sequence
     operations now raise *note TypeError: 2c3. instead of *note
     SystemError: 578. when performed on *note mmap.mmap: 20b. objects.
     Patch by Zackery Spytz.

   - bpo-32684(5): Fix gather to propagate cancellation of itself even
     with return_exceptions.

   - bpo-33674(6): Fix a race condition in SSLProtocol.connection_made()
     of asyncio.sslproto: start immediately the handshake instead of
     using call_soon().  Previously, data_received() could be called
     before the handshake started, causing the handshake to hang or
     fail.

   - bpo-31647(7): Fixed bug where calling write_eof() on a
     _SelectorSocketTransport after it’s already closed raises
     AttributeError.

   - bpo-33672(8): Fix Task.__repr__ crash with Cython’s bogus
     coroutines

   - bpo-33469(9): Fix RuntimeError after closing loop that used
     run_in_executor

   - bpo-11874(10): Use a better regex when breaking usage into
     wrappable parts.  Avoids bogus assertion errors from custom metavar
     strings.

   - bpo-30877(11): Fixed a bug in the Python implementation of the JSON
     decoder that prevented the cache of parsed strings from clearing
     after finishing the decoding.  Based on patch by c-fos.

   - bpo-33548(12): tempfile._candidate_tempdir_list should consider
     common TEMP locations

   - bpo-33542(13): Prevent ‘uuid.get_node’ from using a DUID instead of
     a MAC on Windows.  Patch by Zvi Effron

   - bpo-26819(14): Fix race condition with
     ‘ReadTransport.resume_reading’ in Windows proactor event loop.

   - bpo-28556(15): Minor fixes in typing module: add annotations to
     ‘NamedTuple.__new__’, pass ‘*args’ and ‘**kwds’ in
     ‘Generic.__new__’.  Original PRs by Paulius Šarka and Chad
     Dombrova.

   - bpo-20087(16): Updated alias mapping with glibc 2.27 supported
     locales.

   - bpo-33422(17): Fix trailing quotation marks getting deleted when
     looking up byte/string literals on pydoc.  Patch by Andrés Delfino.

   - bpo-33197(18): Update error message when constructing invalid
     inspect.Parameters Patch by Donghee Na.

   - bpo-33383(19): Fixed crash in the get() method of the *note
     dbm.ndbm: 34. database object when it is called with a single
     argument.

   - bpo-33329(20): Fix multiprocessing regression on newer glibcs

   - bpo-991266(21): Fix quoting of the ‘Comment’ attribute of *note
     http.cookies.SimpleCookie: 1bd3.

   - bpo-33131(22): Upgrade bundled version of pip to 10.0.1.

   - bpo-33308(23): Fixed a crash in the ‘parser’ module when converting
     an ST object to a tree of tuples or lists with ‘line_info=False’
     and ‘col_info=True’.

   - bpo-33263(24): Fix FD leak in ‘_SelectorSocketTransport’ Patch by
     Vlad Starostin.

   - bpo-33256(25): Fix display of ‘<module>’ call in the html produced
     by ‘cgitb.html()’.  Patch by Stéphane Blondon.

   - bpo-33203(26): ‘random.Random.choice()’ now raises ‘IndexError’ for
     empty sequences consistently even when called from subclasses
     without a ‘getrandbits()’ implementation.

   - bpo-33224(27): Update difflib.mdiff() for PEP 479(28).  Convert an
     uncaught StopIteration in a generator into a return-statement.

   - bpo-33209(29): End framing at the end of C implementation of *note
     pickle.Pickler.dump(): 1bd5.

   - bpo-32861(30): The urllib.robotparser’s ‘__str__’ representation
     now includes wildcard entries and the “Crawl-delay” and
     “Request-rate” fields.  Patch by Michael Lazar.

   - bpo-33096(31): Allow ttk.Treeview.insert to insert iid that has a
     false boolean value.  Note iid=0 and iid=False would be same.
     Patch by Garvit Khatri.

   - bpo-33127(32): The ssl module now compiles with LibreSSL 2.7.1.

   - bpo-33021(33): Release the GIL during fstat() calls, avoiding hang
     of all threads when calling mmap.mmap(), os.urandom(), and
     random.seed().  Patch by Nir Soffer.

   - bpo-27683(34): Fix a regression in *note ipaddress: 80. that result
     of ‘hosts()’ is empty when the network is constructed by a tuple
     containing an integer mask and only 1 bit left for addresses.

   - bpo-32844(35): Fix wrong redirection of a low descriptor (0 or 1)
     to stderr in subprocess if another low descriptor is closed.

   - bpo-31908(36): Fix output of cover files for ‘trace’ module
     command-line tool.  Previously emitted cover files only when
     ‘--missing’ option was used.  Patch by Michael Selik.

   - bpo-31457(37): If nested log adapters are used, the inner
     ‘process()’ methods are no longer omitted.

   - bpo-16865(38): Support arrays >=2GiB in *note ctypes: 2a.  Patch by
     Segev Finer.

   - bpo-31238(39): pydoc: the stop() method of the private ServerThread
     class now waits until DocServer.serve_until_quit() completes and
     then explicitly sets its docserver attribute to None to break a
     reference cycle.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30167

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33812

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30805

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33767

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32684

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33674

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31647

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33672

   (9) https://bugs.python.org/issue?@action=redirect&bpo=33469

   (10) https://bugs.python.org/issue?@action=redirect&bpo=11874

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30877

   (12) https://bugs.python.org/issue?@action=redirect&bpo=33548

   (13) https://bugs.python.org/issue?@action=redirect&bpo=33542

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26819

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (16) https://bugs.python.org/issue?@action=redirect&bpo=20087

   (17) https://bugs.python.org/issue?@action=redirect&bpo=33422

   (18) https://bugs.python.org/issue?@action=redirect&bpo=33197

   (19) https://bugs.python.org/issue?@action=redirect&bpo=33383

   (20) https://bugs.python.org/issue?@action=redirect&bpo=33329

   (21) https://bugs.python.org/issue?@action=redirect&bpo=991266

   (22) https://bugs.python.org/issue?@action=redirect&bpo=33131

   (23) https://bugs.python.org/issue?@action=redirect&bpo=33308

   (24) https://bugs.python.org/issue?@action=redirect&bpo=33263

   (25) https://bugs.python.org/issue?@action=redirect&bpo=33256

   (26) https://bugs.python.org/issue?@action=redirect&bpo=33203

   (27) https://bugs.python.org/issue?@action=redirect&bpo=33224

   (28) https://peps.python.org/pep-0479/

   (29) https://bugs.python.org/issue?@action=redirect&bpo=33209

   (30) https://bugs.python.org/issue?@action=redirect&bpo=32861

   (31) https://bugs.python.org/issue?@action=redirect&bpo=33096

   (32) https://bugs.python.org/issue?@action=redirect&bpo=33127

   (33) https://bugs.python.org/issue?@action=redirect&bpo=33021

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27683

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32844

   (36) https://bugs.python.org/issue?@action=redirect&bpo=31908

   (37) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (38) https://bugs.python.org/issue?@action=redirect&bpo=16865

   (39) https://bugs.python.org/issue?@action=redirect&bpo=31238


File: python.info,  Node: Documentation<65>,  Next: Tests<65>,  Prev: Library<150>,  Up: Python 3 6 6 release candidate 1

1.23.76.3 Documentation
.......................

   - bpo-33503(1): Fix broken pypi link

   - bpo-33421(2): Add missing documentation for
     ‘typing.AsyncContextManager’.

   - bpo-33378(3): Add Korean language switcher for
     ‘https://docs.python.org/3/’

   - bpo-33276(4): Clarify that the ‘__path__’ attribute on modules
     cannot be just any value.

   - bpo-33201(5): Modernize documentation for writing C extension
     types.

   - bpo-33195(6): Deprecate ‘Py_UNICODE’ usage in ‘c-api/arg’ document.
     ‘Py_UNICODE’ related APIs are deprecated since Python 3.3, but it
     is missed in the document.

   - bpo-33126(7): Document PyBuffer_ToContiguous().

   - bpo-27212(8): Modify documentation for the ‘islice()’ recipe to
     consume initial values up to the start index.

   - bpo-28247(9): Update *note zipapp: 130. documentation to describe
     how to make standalone applications.

   - bpo-18802(10): Documentation changes for ipaddress.  Patch by Jon
     Foster and Berker Peksag.

   - bpo-27428(11): Update documentation to clarify that
     ‘WindowsRegistryFinder’ implements ‘MetaPathFinder’.  (Patch by
     Himanshu Lakhara)

   - bpo-8243(12): Add a note about curses.addch and curses.addstr
     exception behavior when writing outside a window, or pad.

   - bpo-31432(13): Clarify meaning of CERT_NONE, CERT_OPTIONAL, and
     CERT_REQUIRED flags for ssl.SSLContext.verify_mode.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33503

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33421

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33378

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33276

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33201

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33195

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33126

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27212

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28247

   (10) https://bugs.python.org/issue?@action=redirect&bpo=18802

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27428

   (12) https://bugs.python.org/issue?@action=redirect&bpo=8243

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31432


File: python.info,  Node: Tests<65>,  Next: Build<70>,  Prev: Documentation<65>,  Up: Python 3 6 6 release candidate 1

1.23.76.4 Tests
...............

   - bpo-33655(1): Ignore test_posix_fallocate failures on BSD platforms
     that might be due to running on ZFS.

   - bpo-19417(2): Add test_bdb.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33655

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19417


File: python.info,  Node: Build<70>,  Next: Windows<62>,  Prev: Tests<65>,  Up: Python 3 6 6 release candidate 1

1.23.76.5 Build
...............

   - bpo-5755(1): Move ‘-Wstrict-prototypes’ option to ‘CFLAGS_NODIST’
     from ‘OPT’.  This option emitted annoying warnings when building
     extension modules written in C++.

   - bpo-33614(2): Ensures module definition files for the stable ABI on
     Windows are correctly regenerated.

   - bpo-33522(3): Enable CI builds on Visual Studio Team Services at
     ‘https://python.visualstudio.com/cpython’

   - bpo-33012(4): Add ‘-Wno-cast-function-type’ for gcc 8 for silencing
     warnings about function casts like casting to PyCFunction in method
     definition lists.

   - bpo-33394(5): Enable the verbose build for extension modules, when
     GNU make is passed macros on the command line.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5755

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33614

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33522

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33012

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33394


File: python.info,  Node: Windows<62>,  Next: macOS<49>,  Prev: Build<70>,  Up: Python 3 6 6 release candidate 1

1.23.76.6 Windows
.................

   - bpo-33184(1): Update Windows installer to OpenSSL 1.0.2o.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33184


File: python.info,  Node: macOS<49>,  Next: IDLE<50>,  Prev: Windows<62>,  Up: Python 3 6 6 release candidate 1

1.23.76.7 macOS
...............

   - bpo-33184(1): Update macOS installer build to use OpenSSL 1.0.2o.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33184


File: python.info,  Node: IDLE<50>,  Next: Tools/Demos<37>,  Prev: macOS<49>,  Up: Python 3 6 6 release candidate 1

1.23.76.8 IDLE
..............

   - bpo-33656(1): On Windows, add API call saying that tk scales for
     DPI. On Windows 8.1+ or 10, with DPI compatibility properties of
     the Python binary unchanged, and a monitor resolution greater than
     96 DPI, this should make text and lines sharper.  It should
     otherwise have no effect.

   - bpo-33768(2): Clicking on a context line moves that line to the top
     of the editor window.

   - bpo-33763(3): IDLE: Use read-only text widget for code context
     instead of label widget.

   - bpo-33664(4): Scroll IDLE editor text by lines.  Previously, the
     mouse wheel and scrollbar slider moved text by a fixed number of
     pixels, resulting in partial lines at the top of the editor box.
     The change also applies to the shell and grep output windows, but
     not to read-only text views.

   - bpo-33679(5): Enable theme-specific color configuration for Code
     Context.  Use the Highlights tab to see the setting for built-in
     themes or add settings to custom themes.

   - bpo-33642(6): Display up to maxlines non-blank lines for Code
     Context.  If there is no current context, show a single blank line.

   - bpo-33628(7): IDLE: Cleanup codecontext.py and its test.

   - bpo-33564(8): IDLE’s code context now recognizes async as a block
     opener.

   - bpo-29706(9): IDLE now colors async and await as keywords in 3.6.
     They become full keywords in 3.7.

   - bpo-21474(10): Update word/identifier definition from ascii to
     unicode.  In text and entry boxes, this affects selection by
     double-click, movement left/right by control-left/right, and
     deletion left/right by control-BACKSPACE/DEL.

   - bpo-33204(11): IDLE: consistently color invalid string prefixes.  A
     ‘u’ string prefix cannot be paired with either ‘r’ or ‘f’.
     Consistently color as much of the prefix, starting at the right, as
     is valid.  Revise and extend colorizer test.

   - bpo-32831(12): Add docstrings and tests for codecontext.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33656

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33768

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33763

   (4) https://bugs.python.org/issue?@action=redirect&bpo=33664

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33679

   (6) https://bugs.python.org/issue?@action=redirect&bpo=33642

   (7) https://bugs.python.org/issue?@action=redirect&bpo=33628

   (8) https://bugs.python.org/issue?@action=redirect&bpo=33564

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29706

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21474

   (11) https://bugs.python.org/issue?@action=redirect&bpo=33204

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32831


File: python.info,  Node: Tools/Demos<37>,  Next: C API<63>,  Prev: IDLE<50>,  Up: Python 3 6 6 release candidate 1

1.23.76.9 Tools/Demos
.....................

   - bpo-33189(1): ‘pygettext.py’ now recognizes only literal strings as
     docstrings and translatable strings, and rejects bytes literals and
     f-string expressions.

   - bpo-31920(2): Fixed handling directories as arguments in the
     ‘pygettext’ script.  Based on patch by Oleg Krasnikov.

   - bpo-29673(3): Fix pystackv and pystack gdbinit macros.

   - bpo-32885(4): Add an ‘-n’ flag for ‘Tools/scripts/pathfix.py’ to
     disable automatic backup creation (files with ‘~’ suffix).

   - bpo-31583(5): Fix 2to3 for using with –add-suffix option but
     without –output-dir option for relative path to files in current
     directory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33189

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31920

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29673

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32885

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31583


File: python.info,  Node: C API<63>,  Prev: Tools/Demos<37>,  Up: Python 3 6 6 release candidate 1

1.23.76.10 C API
................

   - bpo-32374(1): Document that m_traverse for multi-phase initialized
     modules can be called with m_state=NULL, and add a sanity check

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32374


File: python.info,  Node: Python 3 6 5 final,  Next: Python 3 6 5 release candidate 1,  Prev: Python 3 6 6 release candidate 1,  Up: Changelog

1.23.77 Python 3.6.5 final
--------------------------

'Release date: 2018-03-28'

* Menu:

* Tests: Tests<66>.
* Build: Build<71>.


File: python.info,  Node: Tests<66>,  Next: Build<71>,  Up: Python 3 6 5 final

1.23.77.1 Tests
...............

   - bpo-32872(1): Avoid regrtest compatibility issue with namespace
     packages.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32872


File: python.info,  Node: Build<71>,  Prev: Tests<66>,  Up: Python 3 6 5 final

1.23.77.2 Build
...............

   - bpo-33163(1): Upgrade pip to 9.0.3 and setuptools to v39.0.1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33163


File: python.info,  Node: Python 3 6 5 release candidate 1,  Next: Python 3 6 4 final,  Prev: Python 3 6 5 final,  Up: Changelog

1.23.78 Python 3.6.5 release candidate 1
----------------------------------------

'Release date: 2018-03-13'

* Menu:

* Security: Security<47>.
* Core and Builtins: Core and Builtins<148>.
* Library: Library<151>.
* Documentation: Documentation<66>.
* Tests: Tests<67>.
* Build: Build<72>.
* Windows: Windows<63>.
* macOS: macOS<50>.
* IDLE: IDLE<51>.
* Tools/Demos: Tools/Demos<38>.
* C API: C API<64>.


File: python.info,  Node: Security<47>,  Next: Core and Builtins<148>,  Up: Python 3 6 5 release candidate 1

1.23.78.1 Security
..................

   - bpo-33001(1): Minimal fix to prevent buffer overrun in os.symlink
     on Windows

   - bpo-32981(2): Regexes in difflib and poplib were vulnerable to
     catastrophic backtracking.  These regexes formed potential DOS
     vectors (REDOS). They have been refactored.  This resolves CVE
     2018-1060(3) and CVE 2018-1061(4).  Patch by Jamie Davis.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33001

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32981

   (3) https://www.cve.org/CVERecord?id=CVE-2018-1060

   (4) https://www.cve.org/CVERecord?id=CVE-2018-1061


File: python.info,  Node: Core and Builtins<148>,  Next: Library<151>,  Prev: Security<47>,  Up: Python 3 6 5 release candidate 1

1.23.78.2 Core and Builtins
...........................

   - bpo-33026(1): Fixed jumping out of “with” block by setting
     f_lineno.

   - bpo-17288(2): Prevent jumps from ‘return’ and ‘exception’ trace
     events.

   - bpo-32889(3): Update Valgrind suppression list to account for the
     rename of ‘Py_ADDRESS_IN_RANG’ to ‘address_in_range’.

   - bpo-32650(4): Pdb and other debuggers dependent on bdb.py will
     correctly step over (next command) native coroutines.  Patch by
     Pablo Galindo.

   - bpo-32685(5): Improve suggestion when the Python 2 form of print
     statement is either present on the same line as the header of a
     compound statement or else terminated by a semi-colon instead of a
     newline.  Patch by Nitish Chandra.

   - bpo-32583(6): Fix possible crashing in builtin Unicode decoders
     caused by write out-of-bound errors when using customized decode
     error handlers.

   - bpo-26163(7): Improved frozenset() hash to create more distinct
     hash values when faced with datasets containing many similar
     values.

   - bpo-27169(8): The ‘__debug__’ constant is now optimized out at
     compile time.  This fixes also bpo-22091(9).

   - bpo-32329(10): ‘sys.flags.hash_randomization’ is now properly set
     to 0 when hash randomization is turned off by ‘PYTHONHASHSEED=0’.

   - bpo-30416(11): The optimizer is now protected from spending much
     time doing complex calculations and consuming much memory for
     creating large constants in constant folding.

   - bpo-18533(12): ‘repr()’ on a dict containing its own ‘values()’ or
     ‘items()’ no longer raises ‘RecursionError’; OrderedDict similarly.
     Instead, use ‘...’, as for other recursive structures.  Patch by
     Ben North.

   - bpo-32028(13): Leading whitespace is now correctly ignored when
     generating suggestions for converting Py2 print statements to Py3
     builtin print function calls.  Patch by Sanyam Khurana.

   - bpo-32137(14): The repr of deeply nested dict now raises a
     RecursionError instead of crashing due to a stack overflow.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33026

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17288

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32889

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32650

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32685

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32583

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26163

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27169

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22091

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32329

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30416

   (12) https://bugs.python.org/issue?@action=redirect&bpo=18533

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32028

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32137


File: python.info,  Node: Library<151>,  Next: Documentation<66>,  Prev: Core and Builtins<148>,  Up: Python 3 6 5 release candidate 1

1.23.78.3 Library
.................

   - bpo-33064(1): lib2to3 now properly supports trailing commas after
     ‘*args’ and ‘**kwargs’ in function signatures.

   - bpo-31804(2): Avoid failing in multiprocessing.Process if the
     standard streams are closed or None at exit.

   - bpo-33037(3): Skip sending/receiving data after SSL transport
     closing.

   - bpo-30353(4): Fix ctypes pass-by-value for structs on 64-bit
     Cygwin/MinGW.

   - bpo-33009(5): Fix inspect.signature() for single-parameter
     partialmethods.

   - bpo-32969(6): Expose several missing constants in zlib and fix
     corresponding documentation.

   - bpo-32713(7): Fixed tarfile.itn handling of out-of-bounds float
     values.  Patch by Joffrey Fuhrer.

   - bpo-30622(8): The ssl module now detects missing NPN support in
     LibreSSL.

   - bpo-32922(9): dbm.open() now encodes filename with the filesystem
     encoding rather than default encoding.

   - bpo-32859(10): In ‘os.dup2’, don’t check every call whether the
     ‘dup3’ syscall exists or not.

   - bpo-21060(11): Rewrite confusing message from setup.py upload from
     “No dist file created in earlier command” to the more helpful “Must
     create and upload files in one command”.

   - bpo-32857(12): In *note tkinter: f0, ‘after_cancel(None)’ now
     raises a *note ValueError: 202. instead of canceling the first
     scheduled function.  Patch by Cheryl Sabella.

   - bpo-32852(13): Make sure sys.argv remains as a list when running
     trace.

   - bpo-32841(14): Fixed ‘asyncio.Condition’ issue which silently
     ignored cancellation after notifying and cancelling a conditional
     lock.  Patch by Bar Harel.

   - bpo-31787(15): Fixed refleaks of ‘__init__()’ methods in various
     modules.  (Contributed by Oren Milman)

   - bpo-30157(16): Fixed guessing quote and delimiter in
     csv.Sniffer.sniff() when only the last field is quoted.  Patch by
     Jake Davis.

   - bpo-32394(17): socket: Remove TCP_FASTOPEN, TCP_KEEPCNT flags on
     older version Windows during run-time.

   - bpo-32777(18): Fix a rare but potential pre-exec child process
     deadlock in subprocess on POSIX systems when marking file
     descriptors inheritable on exec in the child process.  This bug
     appears to have been introduced in 3.4.

   - bpo-32647(19): The ctypes module used to depend on indirect linking
     for dlopen.  The shared extension is now explicitly linked against
     libdl on platforms with dl.

   - bpo-32734(20): Fixed ‘asyncio.Lock()’ safety issue which allowed
     acquiring and locking the same lock multiple times, without it
     being free.  Patch by Bar Harel.

   - bpo-32727(21): Do not include name field in SMTP envelope from
     address.  Patch by Stéphane Wirtel

   - bpo-27931(22): Fix email address header parsing error when the
     username is an empty quoted string.  Patch by Xiang Zhang.

   - bpo-32304(23): distutils’ upload command no longer corrupts tar
     files ending with a CR byte, and no longer tries to convert CR to
     CRLF in any of the upload text fields.

   - bpo-32502(24): uuid.uuid1 no longer raises an exception if a 64-bit
     hardware address is encountered.

   - bpo-31848(25): Fix the error handling in Aifc_read.initfp() when
     the SSND chunk is not found.  Patch by Zackery Spytz.

   - bpo-32555(26): On FreeBSD and Solaris, os.strerror() now always
     decode the byte string from the current locale encoding, rather
     than using ASCII/surrogateescape in some cases.

   - bpo-32521(27): The nis module is now compatible with new libnsl and
     headers location.

   - bpo-32473(28): Improve ABCMeta._dump_registry() output readability

   - bpo-32521(29): glibc has removed Sun RPC. Use replacement libtirpc
     headers and library in nis module.

   - bpo-32228(30): Ensure that ‘truncate()’ preserves the file position
     (as reported by ‘tell()’) after writes longer than the buffer size.

   - bpo-26133(31): Don’t unsubscribe signals in asyncio UNIX event loop
     on interpreter shutdown.

   - bpo-32185(32): The SSL module no longer sends IP addresses in SNI
     TLS extension on platforms with OpenSSL 1.0.2+ or inet_pton.

   - bpo-32323(33): *note urllib.parse.urlsplit(): d67. does not convert
     zone-id (scope) to lower case for scoped IPv6 addresses in
     hostnames now.

   - bpo-32302(34): Fix bdist_wininst of distutils for CRT v142: it
     binary compatible with CRT v140.

   - bpo-32255(35): A single empty field is now always quoted when
     written into a CSV file.  This allows to distinguish an empty row
     from a row consisting of a single empty field.  Patch by Licht
     Takeuchi.

   - bpo-32277(36): Raise ‘NotImplementedError’ instead of ‘SystemError’
     on platforms where ‘chmod(..., follow_symlinks=False)’ is not
     supported.  Patch by Anthony Sottile.

   - bpo-32199(37): The getnode() ip getter now uses ‘ip link’ instead
     of ‘ip link list’.

   - bpo-27456(38): Ensure TCP_NODELAY is set on Linux.  Tests by Victor
     Stinner.

   - bpo-31900(39): The *note locale.localeconv(): c1e. function now
     sets temporarily the ‘LC_CTYPE’ locale to the ‘LC_NUMERIC’ locale
     to decode ‘decimal_point’ and ‘thousands_sep’ byte strings if they
     are non-ASCII or longer than 1 byte, and the ‘LC_NUMERIC’ locale is
     different than the ‘LC_CTYPE’ locale.  This temporary change
     affects other threads.  Same change for the *note str.format():
     624. method when formatting a number (*note int: 257, *note float:
     2f7, ‘float’ and subclasses) with the ‘n’ type (ex:
     ‘'{:n}'.format(1234)’).

   - bpo-31802(40): Importing native path module (‘posixpath’, ‘ntpath’)
     now works even if the ‘os’ module still is not imported.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33064

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31804

   (3) https://bugs.python.org/issue?@action=redirect&bpo=33037

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30353

   (5) https://bugs.python.org/issue?@action=redirect&bpo=33009

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32969

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32713

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30622

   (9) https://bugs.python.org/issue?@action=redirect&bpo=32922

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32859

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21060

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32857

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32852

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32841

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31787

   (16) https://bugs.python.org/issue?@action=redirect&bpo=30157

   (17) https://bugs.python.org/issue?@action=redirect&bpo=32394

   (18) https://bugs.python.org/issue?@action=redirect&bpo=32777

   (19) https://bugs.python.org/issue?@action=redirect&bpo=32647

   (20) https://bugs.python.org/issue?@action=redirect&bpo=32734

   (21) https://bugs.python.org/issue?@action=redirect&bpo=32727

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27931

   (23) https://bugs.python.org/issue?@action=redirect&bpo=32304

   (24) https://bugs.python.org/issue?@action=redirect&bpo=32502

   (25) https://bugs.python.org/issue?@action=redirect&bpo=31848

   (26) https://bugs.python.org/issue?@action=redirect&bpo=32555

   (27) https://bugs.python.org/issue?@action=redirect&bpo=32521

   (28) https://bugs.python.org/issue?@action=redirect&bpo=32473

   (29) https://bugs.python.org/issue?@action=redirect&bpo=32521

   (30) https://bugs.python.org/issue?@action=redirect&bpo=32228

   (31) https://bugs.python.org/issue?@action=redirect&bpo=26133

   (32) https://bugs.python.org/issue?@action=redirect&bpo=32185

   (33) https://bugs.python.org/issue?@action=redirect&bpo=32323

   (34) https://bugs.python.org/issue?@action=redirect&bpo=32302

   (35) https://bugs.python.org/issue?@action=redirect&bpo=32255

   (36) https://bugs.python.org/issue?@action=redirect&bpo=32277

   (37) https://bugs.python.org/issue?@action=redirect&bpo=32199

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27456

   (39) https://bugs.python.org/issue?@action=redirect&bpo=31900

   (40) https://bugs.python.org/issue?@action=redirect&bpo=31802


File: python.info,  Node: Documentation<66>,  Next: Tests<67>,  Prev: Library<151>,  Up: Python 3 6 5 release candidate 1

1.23.78.4 Documentation
.......................

   - bpo-17232(1): Clarify docs for -O and -OO. Patch by Terry Reedy.

   - bpo-32800(2): Update link to w3c doc for xml default namespaces.

   - bpo-8722(3): Document ‘__getattr__()’ behavior when property
     ‘get()’ method raises *note AttributeError: 34e.

   - bpo-32614(4): Modify RE examples in documentation to use raw
     strings to prevent *note DeprecationWarning: 1a5. and add text to
     REGEX HOWTO to highlight the deprecation.

   - bpo-31972(5): Improve docstrings for ‘pathlib.PurePath’ subclasses.

   - bpo-17799(6): Explain real behaviour of sys.settrace and
     sys.setprofile and their C-API counterparts regarding which type of
     events are received in each function.  Patch by Pablo Galindo
     Salgado.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=17232

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32800

   (3) https://bugs.python.org/issue?@action=redirect&bpo=8722

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32614

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31972

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17799


File: python.info,  Node: Tests<67>,  Next: Build<72>,  Prev: Documentation<66>,  Up: Python 3 6 5 release candidate 1

1.23.78.5 Tests
...............

   - bpo-32517(1): Fix failing ‘test_asyncio’ on macOS 10.12.2+ due to
     transport of ‘KqueueSelector’ loop was not being closed.

   - bpo-32721(2): Fix test_hashlib to not fail if the _md5 module is
     not built.

   - bpo-32252(3): Fix faulthandler_suppress_crash_report() used to
     prevent core dump files when testing crashes.  getrlimit() returns
     zero on success.

   - bpo-31518(4): Debian Unstable has disabled TLS 1.0 and 1.1 for
     SSLv23_METHOD().  Change TLS/SSL protocol of some tests to
     PROTOCOL_TLS or PROTOCOL_TLSv1_2 to make them pass on Debian.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32517

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32721

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32252

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31518


File: python.info,  Node: Build<72>,  Next: Windows<63>,  Prev: Tests<67>,  Up: Python 3 6 5 release candidate 1

1.23.78.6 Build
...............

   - bpo-32635(1): Fix segfault of the crypt module when libxcrypt is
     provided instead of libcrypt at the system.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32635


File: python.info,  Node: Windows<63>,  Next: macOS<50>,  Prev: Build<72>,  Up: Python 3 6 5 release candidate 1

1.23.78.7 Windows
.................

   - bpo-33016(1): Fix potential use of uninitialized memory in
     nt._getfinalpathname

   - bpo-32903(2): Fix a memory leak in os.chdir() on Windows if the
     current directory is set to a UNC path.

   - bpo-31966(3): Fixed WindowsConsoleIO.write() for writing empty
     data.

   - bpo-32409(4): Ensures activate.bat can handle Unicode contents.

   - bpo-32457(5): Improves handling of denormalized executable path
     when launching Python.

   - bpo-32370(6): Use the correct encoding for ipconfig output in the
     uuid module.  Patch by Segev Finer.

   - bpo-29248(7): Fix *note os.readlink(): 929. on Windows, which was
     mistakenly treating the ‘PrintNameOffset’ field of the reparse data
     buffer as a number of characters instead of bytes.  Patch by Craig
     Holmquist and SSE4.

   - bpo-32588(8): Create standalone _distutils_findvs module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33016

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32903

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31966

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32409

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32457

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32370

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29248

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32588


File: python.info,  Node: macOS<50>,  Next: IDLE<51>,  Prev: Windows<63>,  Up: Python 3 6 5 release candidate 1

1.23.78.8 macOS
...............

   - bpo-32726(1): Provide an additional, more modern macOS installer
     variant that supports macOS 10.9+ systems in 64-bit mode only.
     Upgrade the supplied third-party libraries to OpenSSL 1.0.2n, XZ
     5.2.3, and SQLite 3.22.0.  The 10.9+ installer now links with and
     supplies its own copy of Tcl/Tk 8.6.8.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32726


File: python.info,  Node: IDLE<51>,  Next: Tools/Demos<38>,  Prev: macOS<50>,  Up: Python 3 6 5 release candidate 1

1.23.78.9 IDLE
..............

   - bpo-32984(1): Set ‘__file__’ while running a startup file.  Like
     Python, IDLE optionally runs one startup file in the Shell window
     before presenting the first interactive input prompt.  For IDLE,
     ‘-s’ runs a file named in environmental variable ‘IDLESTARTUP’ or
     *note PYTHONSTARTUP: 1003.; ‘-r file’ runs ‘file’.  Python sets
     ‘__file__’ to the startup file name before running the file and
     unsets it before the first prompt.  IDLE now does the same when run
     normally, without the ‘-n’ option.

   - bpo-32940(2): Simplify and rename StringTranslatePseudoMapping in
     pyparse.

   - bpo-32916(3): Change ‘str’ to ‘code’ in pyparse.

   - bpo-32905(4): Remove unused code in pyparse module.

   - bpo-32874(5): Add tests for pyparse.

   - bpo-32837(6): Using the system and place-dependent default encoding
     for open() is a bad idea for IDLE’s system and location-independent
     files.

   - bpo-32826(7): Add “encoding=utf-8” to open() in IDLE’s
     test_help_about.  GUI test test_file_buttons() only looks at
     initial ascii-only lines, but failed on systems where open()
     defaults to ‘ascii’ because readline() internally reads and decodes
     far enough ahead to encounter a non-ascii character in CREDITS.txt.

   - bpo-32765(8): Update configdialog General tab docstring to add new
     widgets to the widget list.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32984

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32940

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32916

   (4) https://bugs.python.org/issue?@action=redirect&bpo=32905

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32874

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32837

   (7) https://bugs.python.org/issue?@action=redirect&bpo=32826

   (8) https://bugs.python.org/issue?@action=redirect&bpo=32765


File: python.info,  Node: Tools/Demos<38>,  Next: C API<64>,  Prev: IDLE<51>,  Up: Python 3 6 5 release candidate 1

1.23.78.10 Tools/Demos
......................

   - bpo-24960(1): 2to3 and lib2to3 can now read pickled grammar files
     using pkgutil.get_data() rather than probing the filesystem.  This
     lets 2to3 and lib2to3 work when run from a zipfile.

   - bpo-32222(2): Fix pygettext not extracting docstrings for functions
     with type annotated arguments.  Patch by Toby Harradine.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24960

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32222


File: python.info,  Node: C API<64>,  Prev: Tools/Demos<38>,  Up: Python 3 6 5 release candidate 1

1.23.78.11 C API
................

   - bpo-29084(1): Undocumented C API for OrderedDict has been excluded
     from the limited C API. It was added by mistake and actually never
     worked in the limited C API.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29084


File: python.info,  Node: Python 3 6 4 final,  Next: Python 3 6 4 release candidate 1,  Prev: Python 3 6 5 release candidate 1,  Up: Changelog

1.23.79 Python 3.6.4 final
--------------------------

'Release date: 2017-12-18'

There were no new code changes in version 3.6.4 since v3.6.4rc1.


File: python.info,  Node: Python 3 6 4 release candidate 1,  Next: Python 3 6 3 final,  Prev: Python 3 6 4 final,  Up: Changelog

1.23.80 Python 3.6.4 release candidate 1
----------------------------------------

'Release date: 2017-12-05'

* Menu:

* Core and Builtins: Core and Builtins<149>.
* Library: Library<152>.
* Documentation: Documentation<67>.
* Tests: Tests<68>.
* Build: Build<73>.
* Windows: Windows<64>.
* macOS: macOS<51>.
* IDLE: IDLE<52>.
* Tools/Demos: Tools/Demos<39>.
* C API: C API<65>.


File: python.info,  Node: Core and Builtins<149>,  Next: Library<152>,  Up: Python 3 6 4 release candidate 1

1.23.80.1 Core and Builtins
...........................

   - bpo-32176(1): co_flags.CO_NOFREE is now always set correctly by the
     code object constructor based on freevars and cellvars, rather than
     needing to be set correctly by the caller.  This ensures it will be
     cleared automatically when additional cell references are injected
     into a modified code object and function.

   - bpo-31949(2): Fixed several issues in printing tracebacks
     (PyTraceBack_Print()).  Setting sys.tracebacklimit to 0 or less now
     suppresses printing tracebacks.  Setting sys.tracebacklimit to None
     now causes using the default limit.  Setting sys.tracebacklimit to
     an integer larger than LONG_MAX now means using the limit LONG_MAX
     rather than the default limit.  Fixed integer overflows in the case
     of more than ‘2**31’ traceback items on Windows.  Fixed output
     errors handling.

   - bpo-30696(3): Fix the interactive interpreter looping endlessly
     when no memory.

   - bpo-20047(4): Bytearray methods partition() and rpartition() now
     accept only bytes-like objects as separator, as documented.  In
     particular they now raise TypeError rather of returning a bogus
     result when an integer is passed as a separator.

   - bpo-31852(5): Fix a segmentation fault caused by a combination of
     the async soft keyword and continuation lines.

   - bpo-21720(6): BytesWarning no longer emitted when the 'fromlist'
     argument of ‘__import__()’ or the ‘__all__’ attribute of the module
     contain bytes instances.

   - bpo-31825(7): Fixed OverflowError in the ‘unicode-escape’ codec and
     in codecs.escape_decode() when decode an escaped non-ascii byte.

   - bpo-28603(8): Print the full context/cause chain of exceptions on
     interpreter exit, even if an exception in the chain is unhashable
     or compares equal to later ones.  Patch by Zane Bitter.

   - bpo-31786(9): Fix timeout rounding in the select module to round
     correctly negative timeouts between -1.0 and 0.0.  The functions
     now block waiting for events as expected.  Previously, the call was
     incorrectly non-blocking.  Patch by Pablo Galindo.

   - bpo-31642(10): Restored blocking “from package import module” by
     setting sys.modules[“package.module”] to None.

   - bpo-31626(11): Fixed a bug in debug memory allocator.  There was a
     write to freed memory after shrinking a memory block.

   - bpo-31619(12): Fixed a ValueError when convert a string with large
     number of underscores to integer with binary base.

   - bpo-31592(13): Fixed an assertion failure in Python parser in case
     of a bad ‘unicodedata.normalize()’.  Patch by Oren Milman.

   - bpo-31588(14): Raise a ‘TypeError’ with a helpful error message
     when class creation fails due to a metaclass with a bad
     ‘__prepare__()’ method.  Patch by Oren Milman.

   - bpo-31566(15): Fix an assertion failure in ‘_warnings.warn()’ in
     case of a bad ‘__name__’ global.  Patch by Oren Milman.

   - bpo-31505(16): Fix an assertion failure in ‘json’, in case
     ‘_json.make_encoder()’ received a bad ‘encoder()’ argument.  Patch
     by Oren Milman.

   - bpo-31492(17): Fix assertion failures in case of failing to import
     from a module with a bad ‘__name__’ attribute, and in case of
     failing to access an attribute of such a module.  Patch by Oren
     Milman.

   - bpo-31490(18): Fix an assertion failure in ‘ctypes’ class
     definition, in case the class has an attribute whose name is
     specified in ‘_anonymous_’ but not in ‘_fields_’.  Patch by Oren
     Milman.

   - bpo-31478(19): Fix an assertion failure in ‘_random.Random.seed()’
     in case the argument has a bad ‘__abs__()’ method.  Patch by Oren
     Milman.

   - bpo-31315(20): Fix an assertion failure in imp.create_dynamic(),
     when spec.name is not a string.  Patch by Oren Milman.

   - bpo-31311(21): Fix a crash in the ‘__setstate__()’ method of
     ‘ctypes._CData’, in case of a bad ‘__dict__’.  Patch by Oren
     Milman.

   - bpo-31293(22): Fix crashes in true division and multiplication of a
     timedelta object by a float with a bad as_integer_ratio() method.
     Patch by Oren Milman.

   - bpo-31285(23): Fix an assertion failure in
     ‘warnings.warn_explicit’, when the return value of the received
     loader’s ‘get_source()’ has a bad ‘splitlines()’ method.  Patch by
     Oren Milman.

   - bpo-30817(24): ‘PyErr_PrintEx()’ clears now the ignored exception
     that may be raised by ‘_PySys_SetObjectId()’, for example when no
     memory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32176

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31949

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30696

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20047

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31852

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21720

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31825

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31786

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31642

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31626

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31619

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31592

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31588

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31566

   (16) https://bugs.python.org/issue?@action=redirect&bpo=31505

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31492

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31490

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31478

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31315

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31311

   (22) https://bugs.python.org/issue?@action=redirect&bpo=31293

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31285

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30817


File: python.info,  Node: Library<152>,  Next: Documentation<67>,  Prev: Core and Builtins<149>,  Up: Python 3 6 4 release candidate 1

1.23.80.2 Library
.................

   - bpo-28556(1): Two minor fixes for ‘typing’ module: allow shallow
     copying instances of generic classes, improve interaction of
     ‘__init_subclass__’ with generics.  Original PRs by Ivan
     Levkivskyi.

   - bpo-27240(2): The header folding algorithm for the new email
     policies has been rewritten, which also fixes bpo-30788(3),
     bpo-31831(4), and bpo-32182(5).  In particular, RFC2231 folding is
     now done correctly.

   - bpo-32186(6): io.FileIO.readall() and io.FileIO.read() now release
     the GIL when getting the file size.  Fixed hang of all threads with
     inaccessible NFS server.  Patch by Nir Soffer.

   - bpo-12239(7): Make ‘msilib.SummaryInformation.GetProperty()’ return
     ‘None’ when the value of property is ‘VT_EMPTY’.  Initial patch by
     Mark Mc Mahon.

   - bpo-31325(8): Fix wrong usage of *note collections.namedtuple():
     1ca. in the *note RobotFileParser.parse(): 1c34. method.  Initial
     patch by Robin Wellner.

   - bpo-12382(9): ‘msilib.OpenDatabase()’ now raises a better exception
     message when it couldn’t open or create an MSI file.  Initial patch
     by William Tisäter.

   - bpo-32110(10): ‘codecs.StreamReader.read(n)’ now returns not more
     than 'n' characters/bytes for non-negative 'n'.  This makes it
     compatible with ‘read()’ methods of other file-like objects.

   - bpo-32072(11): Fixed issues with binary plists: Fixed saving
     bytearrays.  Identical objects will be saved only once.  Equal
     references will be load as identical objects.  Added support for
     saving and loading recursive data structures.

   - bpo-32034(12): Make asyncio.IncompleteReadError and
     LimitOverrunError pickleable.

   - bpo-32015(13): Fixed the looping of asyncio in the case of
     reconnection the socket during waiting async read/write from/to the
     socket.

   - bpo-32011(14): Restored support of loading marshal files with the
     TYPE_INT64 code.  These files can be produced in Python 2.7.

   - bpo-31970(15): Reduce performance overhead of asyncio debug mode.

   - bpo-9678(16): Fixed determining the MAC address in the uuid module:
     Using ifconfig on NetBSD and OpenBSD. Using arp on Linux, FreeBSD,
     NetBSD and OpenBSD. Based on patch by Takayuki Shimizukawa.

   - bpo-30057(17): Fix potential missed signal in signal.signal().

   - bpo-31933(18): Fix Blake2 params leaf_size and node_offset on big
     endian platforms.  Patch by Jack O’Connor.

   - bpo-31927(19): Fixed compilation of the socket module on NetBSD 8.
     Fixed assertion failure or reading arbitrary data when parse a
     AF_BLUETOOTH address on NetBSD and DragonFly BSD.

   - bpo-27666(20): Fixed stack corruption in curses.box() and
     curses.ungetmouse() when the size of types chtype or mmask_t is
     less than the size of C long.  curses.box() now accepts characters
     as arguments.  Based on patch by Steve Fink.

   - bpo-31897(21): plistlib now catches more errors when read binary
     plists and raises InvalidFileException instead of unexpected
     exceptions.

   - bpo-25720(22): Fix the method for checking pad state of curses
     WINDOW. Patch by Masayuki Yamamoto.

   - bpo-31893(23): Fixed the layout of the kqueue_event structure on
     OpenBSD and NetBSD. Fixed the comparison of the kqueue_event
     objects.

   - bpo-31891(24): Fixed building the curses module on NetBSD.

   - bpo-28416(25): Instances of pickle.Pickler subclass with the
     persistent_id() method and pickle.Unpickler subclass with the
     persistent_load() method no longer create reference cycles.

   - bpo-28326(26): Fix multiprocessing.Process when stdout and/or
     stderr is closed or None.

   - bpo-31457(27): If nested log adapters are used, the inner
     ‘process()’ methods are no longer omitted.

   - bpo-31457(28): The ‘manager’ property on LoggerAdapter objects is
     now properly settable.

   - bpo-31806(29): Fix timeout rounding in time.sleep(),
     threading.Lock.acquire() and socket.socket.settimeout() to round
     correctly negative timeouts between -1.0 and 0.0.  The functions
     now block waiting for events as expected.  Previously, the call was
     incorrectly non-blocking.  Patch by Pablo Galindo.

   - bpo-28603(30): traceback: Fix a TypeError that occurred during
     printing of exception tracebacks when either the current exception
     or an exception in its context/cause chain is unhashable.  Patch by
     Zane Bitter.

   - bpo-30058(31): Fixed buffer overflow in select.kqueue.control().

   - bpo-31770(32): Prevent a crash when calling the ‘__init__()’ method
     of a ‘sqlite3.Cursor’ object more than once.  Patch by Oren Milman.

   - bpo-31672(33): ‘idpattern’ in ‘string.Template’ matched some
     non-ASCII characters.  Now it uses ‘-i’ regular expression local
     flag to avoid non-ASCII characters.

   - bpo-31764(34): Prevent a crash in ‘sqlite3.Cursor.close()’ in case
     the ‘Cursor’ object is uninitialized.  Patch by Oren Milman.

   - bpo-31752(35): Fix possible crash in timedelta constructor called
     with custom integers.

   - bpo-31701(36): On Windows, faulthandler.enable() now ignores MSC
     and COM exceptions.

   - bpo-31728(37): Prevent crashes in ‘_elementtree’ due to unsafe
     cleanup of ‘Element.text’ and ‘Element.tail’.  Patch by Oren
     Milman.

   - bpo-31620(38): an empty asyncio.Queue now doesn’t leak memory when
     queue.get pollers timeout

   - bpo-31632(39): Fix method set_protocol() of class
     _SSLProtocolTransport in asyncio module.  This method was
     previously modifying a wrong reference to the protocol.

   - bpo-31675(40): Fixed memory leaks in Tkinter’s methods splitlist()
     and split() when pass a string larger than 2 GiB.

   - bpo-31673(41): Fixed typo in the name of Tkinter’s method
     adderrorinfo().

   - bpo-30806(42): Fix the string representation of a netrc object.

   - bpo-15037(43): Added a workaround for getkey() in curses for
     ncurses 5.7 and earlier.

   - bpo-25351(44): Avoid venv activate failures with undefined
     variables

   - bpo-25532(45): inspect.unwrap() will now only try to unwrap an
     object sys.getrecursionlimit() times, to protect against objects
     which create a new object on every attribute access.

   - bpo-30347(46): Stop crashes when concurrently iterate over
     itertools.groupby() iterators.

   - bpo-31516(47): ‘threading.current_thread()’ should not return a
     dummy thread at shutdown.

   - bpo-31351(48): python -m ensurepip now exits with non-zero exit
     code if pip bootstrapping has failed.

   - bpo-31482(49): ‘random.seed()’ now works with bytes in version=1

   - bpo-31334(50): Fix ‘poll.poll([timeout])’ in the ‘select’ module
     for arbitrary negative timeouts on all OSes where it can only be a
     non-negative integer or -1.  Patch by Riccardo Coccioli.

   - bpo-31310(51): multiprocessing’s semaphore tracker should be
     launched again if crashed.

   - bpo-31308(52): Make multiprocessing’s forkserver process immune to
     Ctrl-C and other user interruptions.  If it crashes, restart it
     when necessary.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27240

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30788

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31831

   (5) https://bugs.python.org/issue?@action=redirect&bpo=32182

   (6) https://bugs.python.org/issue?@action=redirect&bpo=32186

   (7) https://bugs.python.org/issue?@action=redirect&bpo=12239

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31325

   (9) https://bugs.python.org/issue?@action=redirect&bpo=12382

   (10) https://bugs.python.org/issue?@action=redirect&bpo=32110

   (11) https://bugs.python.org/issue?@action=redirect&bpo=32072

   (12) https://bugs.python.org/issue?@action=redirect&bpo=32034

   (13) https://bugs.python.org/issue?@action=redirect&bpo=32015

   (14) https://bugs.python.org/issue?@action=redirect&bpo=32011

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31970

   (16) https://bugs.python.org/issue?@action=redirect&bpo=9678

   (17) https://bugs.python.org/issue?@action=redirect&bpo=30057

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31933

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31927

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27666

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31897

   (22) https://bugs.python.org/issue?@action=redirect&bpo=25720

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31893

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31891

   (25) https://bugs.python.org/issue?@action=redirect&bpo=28416

   (26) https://bugs.python.org/issue?@action=redirect&bpo=28326

   (27) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (28) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (29) https://bugs.python.org/issue?@action=redirect&bpo=31806

   (30) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30058

   (32) https://bugs.python.org/issue?@action=redirect&bpo=31770

   (33) https://bugs.python.org/issue?@action=redirect&bpo=31672

   (34) https://bugs.python.org/issue?@action=redirect&bpo=31764

   (35) https://bugs.python.org/issue?@action=redirect&bpo=31752

   (36) https://bugs.python.org/issue?@action=redirect&bpo=31701

   (37) https://bugs.python.org/issue?@action=redirect&bpo=31728

   (38) https://bugs.python.org/issue?@action=redirect&bpo=31620

   (39) https://bugs.python.org/issue?@action=redirect&bpo=31632

   (40) https://bugs.python.org/issue?@action=redirect&bpo=31675

   (41) https://bugs.python.org/issue?@action=redirect&bpo=31673

   (42) https://bugs.python.org/issue?@action=redirect&bpo=30806

   (43) https://bugs.python.org/issue?@action=redirect&bpo=15037

   (44) https://bugs.python.org/issue?@action=redirect&bpo=25351

   (45) https://bugs.python.org/issue?@action=redirect&bpo=25532

   (46) https://bugs.python.org/issue?@action=redirect&bpo=30347

   (47) https://bugs.python.org/issue?@action=redirect&bpo=31516

   (48) https://bugs.python.org/issue?@action=redirect&bpo=31351

   (49) https://bugs.python.org/issue?@action=redirect&bpo=31482

   (50) https://bugs.python.org/issue?@action=redirect&bpo=31334

   (51) https://bugs.python.org/issue?@action=redirect&bpo=31310

   (52) https://bugs.python.org/issue?@action=redirect&bpo=31308


File: python.info,  Node: Documentation<67>,  Next: Tests<68>,  Prev: Library<152>,  Up: Python 3 6 4 release candidate 1

1.23.80.3 Documentation
.......................

   - bpo-32105(1): Added asyncio.BaseEventLoop.connect_accepted_socket
     versionadded marker.

   - bpo-31537(2): Fix incorrect usage of ‘get_history_length’ in
     readline documentation example code.  Patch by Brad Smith.

   - bpo-30085(3): The operator functions without double underscores are
     preferred for clarity.  The one with underscores are only kept for
     back-compatibility.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32105

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31537

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30085


File: python.info,  Node: Tests<68>,  Next: Build<73>,  Prev: Documentation<67>,  Up: Python 3 6 4 release candidate 1

1.23.80.4 Tests
...............

   - bpo-31380(1): Skip test_httpservers test_undecodable_file on macOS:
     fails on APFS.

   - bpo-31705(2): Skip test_socket.test_sha256() on Linux kernel older
     than 4.5.  The test fails with ENOKEY on kernel 3.10 (on ppc64le).
     A fix was merged into the kernel 4.5.

   - bpo-31174(3): Fix test_tools.test_unparse: DirectoryTestCase now
     stores the names sample to always test the same files.  It prevents
     false alarms when hunting reference leaks.

   - bpo-30695(4): Add the ‘set_nomemory(start, stop)’ and
     ‘remove_mem_hooks()’ functions to the ‘_testcapi’ module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31380

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31705

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31174

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30695


File: python.info,  Node: Build<73>,  Next: Windows<64>,  Prev: Tests<68>,  Up: Python 3 6 4 release candidate 1

1.23.80.5 Build
...............

   - bpo-32059(1): ‘detect_modules()’ in ‘setup.py’ now also searches
     the sysroot paths when cross-compiling.

   - bpo-31957(2): Fixes Windows SDK version detection when building for
     Windows.

   - bpo-31609(3): Fixes quotes in PCbuild/clean.bat

   - bpo-31934(4): Abort the build when building out of a not clean
     source tree.

   - bpo-31926(5): Fixed Argument Clinic sometimes causing compilation
     errors when there was more than one function and/or method in a .c
     file with the same name.

   - bpo-28791(6): Update Windows builds to use SQLite 3.21.0.

   - bpo-28791(7): Update OS X installer to use SQLite 3.21.0.

   - bpo-22140(8): Prevent double substitution of prefix in
     python-config.sh.

   - bpo-31536(9): Avoid wholesale rebuild after ‘make regen-all’ if
     nothing changed.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32059

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31957

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31609

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31934

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31926

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28791

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28791

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22140

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31536


File: python.info,  Node: Windows<64>,  Next: macOS<51>,  Prev: Build<73>,  Up: Python 3 6 4 release candidate 1

1.23.80.6 Windows
.................

   - bpo-1102(1): Return ‘None’ when ‘View.Fetch()’ returns
     ‘ERROR_NO_MORE_ITEMS’ instead of raising ‘MSIError’.  Initial patch
     by Anthony Tuininga.

   - bpo-31944(2): Fixes Modify button in Apps and Features dialog.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=1102

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31944


File: python.info,  Node: macOS<51>,  Next: IDLE<52>,  Prev: Windows<64>,  Up: Python 3 6 4 release candidate 1

1.23.80.7 macOS
...............

   - bpo-31392(1): Update macOS installer to use OpenSSL 1.0.2m

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31392


File: python.info,  Node: IDLE<52>,  Next: Tools/Demos<39>,  Prev: macOS<51>,  Up: Python 3 6 4 release candidate 1

1.23.80.8 IDLE
..............

   - bpo-32207(1): Improve tk event exception tracebacks in IDLE. When
     tk event handling is driven by IDLE’s run loop, a confusing and
     distracting queue.EMPTY traceback context is no longer added to tk
     event exception tracebacks.  The traceback is now the same as when
     event handling is driven by user code.  Patch based on a suggestion
     by Serhiy Storchaka.

   - bpo-32164(2): Delete unused file idlelib/tabbedpages.py.  Use of
     TabbedPageSet in configdialog was replaced by ttk.Notebook.

   - bpo-32100(3): IDLE: Fix old and new bugs in pathbrowser; improve
     tests.  Patch mostly by Cheryl Sabella.

   - bpo-31858(4): IDLE – Restrict shell prompt manipulation to the
     shell.  Editor and output windows only see an empty last prompt
     line.  This simplifies the code and fixes a minor bug when newline
     is inserted.  Sys.ps1, if present, is read on Shell start-up, but
     is not set or changed.

   - bpo-31860(5): The font sample in the IDLE configuration dialog is
     now editable.  Changes persist while IDLE remains open

   - bpo-31836(6): Test_code_module now passes if run after test_idle,
     which sets ps1.  The code module uses sys.ps1 if present or sets it
     to ‘>>> ‘ if not.  Test_code_module now properly tests both
     behaviors.  Ditto for ps2.

   - bpo-28603(7): Fix a TypeError that caused a shell restart when
     printing a traceback that includes an exception that is unhashable.
     Patch by Zane Bitter.

   - bpo-13802(8): Use non-Latin characters in the IDLE’s Font settings
     sample.  Even if one selects a font that defines a limited subset
     of the unicode Basic Multilingual Plane, tcl/tk will use other
     fonts that define a character.  The expanded example give users of
     non-Latin characters a better idea of what they might see in IDLE’s
     shell and editors.  To make room for the expanded sample, frames on
     the Font tab are re-arranged.  The Font/Tabs help explains a bit
     about the additions.

   - bpo-31460(9): Simplify the API of IDLE’s Module Browser.  Passing a
     widget instead of an flist with a root widget opens the option of
     creating a browser frame that is only part of a window.  Passing a
     full file name instead of pieces assumed to come from a .py file
     opens the possibility of browsing python files that do not end in
     .py.

   - bpo-31649(10): IDLE - Make _htest, _utest parameters keyword only.

   - bpo-31559(11): Remove test order dependence in
     idle_test.test_browser.

   - bpo-31459(12): Rename IDLE’s module browser from Class Browser to
     Module Browser.  The original module-level class and method browser
     became a module browser, with the addition of module-level
     functions, years ago.  Nested classes and functions were added
     yesterday.  For back-compatibility, the virtual event
     <<open-class-browser>>, which appears on the Keys tab of the
     Settings dialog, is not changed.  Patch by Cheryl Sabella.

   - bpo-31500(13): Default fonts now are scaled on HiDPI displays.

   - bpo-1612262(14): IDLE module browser now shows nested classes and
     functions.  Original patches for code and tests by Guilherme Polo
     and Cheryl Sabella, respectively.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32207

   (2) https://bugs.python.org/issue?@action=redirect&bpo=32164

   (3) https://bugs.python.org/issue?@action=redirect&bpo=32100

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31858

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31860

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31836

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28603

   (8) https://bugs.python.org/issue?@action=redirect&bpo=13802

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31460

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31649

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31559

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31459

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31500

   (14) https://bugs.python.org/issue?@action=redirect&bpo=1612262


File: python.info,  Node: Tools/Demos<39>,  Next: C API<65>,  Prev: IDLE<52>,  Up: Python 3 6 4 release candidate 1

1.23.80.9 Tools/Demos
.....................

   - bpo-30722(1): Make redemo work with Python 3.6 and newer versions.
     Also, remove the ‘LOCALE’ option since it doesn’t work with string
     patterns in Python 3.  Patch by Christoph Sarnowski.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30722


File: python.info,  Node: C API<65>,  Prev: Tools/Demos<39>,  Up: Python 3 6 4 release candidate 1

1.23.80.10 C API
................

   - bpo-20891(1): Fix PyGILState_Ensure().  When PyGILState_Ensure() is
     called in a non-Python thread before PyEval_InitThreads(), only
     call PyEval_InitThreads() after calling PyThreadState_New() to fix
     a crash.

   - bpo-31532(2): Fix memory corruption due to allocator mix in
     getpath.c between Py_GetPath() and Py_SetPath()

   - bpo-30697(3): The ‘PyExc_RecursionErrorInst’ singleton is removed
     and ‘PyErr_NormalizeException()’ does not use it anymore.  This
     singleton is persistent and its members being never cleared may
     cause a segfault during finalization of the interpreter.  See also
     bpo-22898(4).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20891

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31532

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30697

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22898


File: python.info,  Node: Python 3 6 3 final,  Next: Python 3 6 3 release candidate 1,  Prev: Python 3 6 4 release candidate 1,  Up: Changelog

1.23.81 Python 3.6.3 final
--------------------------

'Release date: 2017-10-03'

* Menu:

* Library: Library<153>.
* Build: Build<74>.


File: python.info,  Node: Library<153>,  Next: Build<74>,  Up: Python 3 6 3 final

1.23.81.1 Library
.................

   - bpo-31641(1): Re-allow arbitrary iterables in
     ‘concurrent.futures.as_completed()’.  Fixes regression in 3.6.3rc1.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31641


File: python.info,  Node: Build<74>,  Prev: Library<153>,  Up: Python 3 6 3 final

1.23.81.2 Build
...............

   - bpo-31662(1): Fix typos in Windows ‘uploadrelease.bat’ script.  Fix
     Windows Doc build issues in ‘Doc/make.bat’.

   - bpo-31423(2): Fix building the PDF documentation with newer
     versions of Sphinx.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31662

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31423


File: python.info,  Node: Python 3 6 3 release candidate 1,  Next: Python 3 6 2 final,  Prev: Python 3 6 3 final,  Up: Changelog

1.23.82 Python 3.6.3 release candidate 1
----------------------------------------

'Release date: 2017-09-18'

* Menu:

* Security: Security<48>.
* Core and Builtins: Core and Builtins<150>.
* Library: Library<154>.
* Documentation: Documentation<68>.
* Tests: Tests<69>.
* Build: Build<75>.
* Windows: Windows<65>.
* IDLE: IDLE<53>.
* Tools/Demos: Tools/Demos<40>.


File: python.info,  Node: Security<48>,  Next: Core and Builtins<150>,  Up: Python 3 6 3 release candidate 1

1.23.82.1 Security
..................

   - bpo-29781(1): SSLObject.version() now correctly returns None when
     handshake over BIO has not been performed yet.

   - bpo-30947(2): Upgrade libexpat embedded copy from version 2.2.1 to
     2.2.3 to get security fixes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29781

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30947


File: python.info,  Node: Core and Builtins<150>,  Next: Library<154>,  Prev: Security<48>,  Up: Python 3 6 3 release candidate 1

1.23.82.2 Core and Builtins
...........................

   - bpo-31471(1): Fix an assertion failure in ‘subprocess.Popen()’ on
     Windows, in case the env argument has a bad ‘keys()’ method.  Patch
     by Oren Milman.

   - bpo-31418(2): Fix an assertion failure in ‘PyErr_WriteUnraisable()’
     in case of an exception with a bad ‘__module__’ attribute.  Patch
     by Oren Milman.

   - bpo-31416(3): Fix assertion failures in case of a bad
     warnings.filters or warnings.defaultaction.  Patch by Oren Milman.

   - bpo-31411(4): Raise a TypeError instead of SystemError in case
     warnings.onceregistry is not a dictionary.  Patch by Oren Milman.

   - bpo-31373(5): Fix several possible instances of undefined behavior
     due to floating-point demotions.

   - bpo-30465(6): Location information (‘lineno’ and ‘col_offset’) in
     f-strings is now (mostly) correct.  This fixes tools like flake8
     from showing warnings on the wrong line (typically the first line
     of the file).

   - bpo-31343(7): Include sys/sysmacros.h for major(), minor(), and
     makedev().  GNU C libray plans to remove the functions from
     sys/types.h.

   - bpo-31291(8): Fix an assertion failure in
     ‘zipimport.zipimporter.get_data’ on Windows, when the return value
     of ‘pathname.replace('/','\\')’ isn’t a string.  Patch by Oren
     Milman.

   - bpo-31271(9): Fix an assertion failure in the ‘write()’ method of
     ‘io.TextIOWrapper’, when the encoder doesn’t return a bytes object.
     Patch by Oren Milman.

   - bpo-31243(10): Fix a crash in some methods of ‘io.TextIOWrapper’,
     when the decoder’s state is invalid.  Patch by Oren Milman.

   - bpo-30721(11): ‘print’ now shows correct usage hint for using
     Python 2 redirection syntax.  Patch by Sanyam Khurana.

   - bpo-31070(12): Fix a race condition in importlib
     _get_module_lock().

   - bpo-31095(13): Fix potential crash during GC caused by ‘tp_dealloc’
     which doesn’t call ‘PyObject_GC_UnTrack()’.

   - bpo-31071(14): Avoid masking original TypeError in call with *
     unpacking when other arguments are passed.

   - bpo-30978(15): str.format_map() now passes key lookup exceptions
     through.  Previously any exception was replaced with a KeyError
     exception.

   - bpo-30808(16): Use _Py_atomic API for concurrency-sensitive signal
     state.

   - bpo-30876(17): Relative import from unloaded package now reimports
     the package instead of failing with SystemError.  Relative import
     from non-package now fails with ImportError rather than
     SystemError.

   - bpo-30703(18): Improve signal delivery.  Avoid using
     Py_AddPendingCall from signal handler, to avoid calling
     signal-unsafe functions.  The tests I’m adding here fail without
     the rest of the patch, on Linux and OS X. This means our signal
     delivery logic had defects (some signals could be lost).

   - bpo-30765(19): Avoid blocking in pthread_mutex_lock() when
     PyThread_acquire_lock() is asked not to block.

   - bpo-31161(20): Make sure the ‘Missing parentheses’ syntax error
     message is only applied to SyntaxError, not to subclasses.  Patch
     by Martijn Pieters.

   - bpo-30814(21): Fixed a race condition when import a submodule from
     a package.

   - bpo-30597(22): ‘print’ now shows expected input in custom error
     message when used as a Python 2 statement.  Patch by Sanyam
     Khurana.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31471

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31418

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31416

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31411

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31373

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30465

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31343

   (8) https://bugs.python.org/issue?@action=redirect&bpo=31291

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31271

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31243

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30721

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31070

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31095

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31071

   (15) https://bugs.python.org/issue?@action=redirect&bpo=30978

   (16) https://bugs.python.org/issue?@action=redirect&bpo=30808

   (17) https://bugs.python.org/issue?@action=redirect&bpo=30876

   (18) https://bugs.python.org/issue?@action=redirect&bpo=30703

   (19) https://bugs.python.org/issue?@action=redirect&bpo=30765

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31161

   (21) https://bugs.python.org/issue?@action=redirect&bpo=30814

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30597


File: python.info,  Node: Library<154>,  Next: Documentation<68>,  Prev: Core and Builtins<150>,  Up: Python 3 6 3 release candidate 1

1.23.82.3 Library
.................

   - bpo-31499(1): xml.etree: Fix a crash when a parser is part of a
     reference cycle.

   - bpo-28556(2): typing.get_type_hints now finds the right globalns
     for classes and modules by default (when no ‘globalns’ was
     specified by the caller).

   - bpo-28556(3): Speed improvements to the ‘typing’ module.  Original
     PRs by Ivan Levkivskyi and Mitar.

   - bpo-31544(4): The C accelerator module of ElementTree ignored
     exceptions raised when looking up TreeBuilder target methods in
     XMLParser().

   - bpo-31234(5): socket.create_connection() now fixes manually a
     reference cycle: clear the variable storing the last exception on
     success.

   - bpo-31457(6): LoggerAdapter objects can now be nested.

   - bpo-31400(7): Improves SSL error handling to avoid losing error
     numbers.

   - bpo-28958(8): ssl.SSLContext() now uses OpenSSL error information
     when a context cannot be instantiated.

   - bpo-27340(9): SSLSocket.sendall() now uses memoryview to create
     slices of data.  This fixes support for all bytes-like object.  It
     is also more efficient and avoids costly copies.

   - bpo-31178(10): Fix string concatenation bug in rare error path in
     the subprocess module

   - bpo-31350(11): Micro-optimize ‘asyncio._get_running_loop()’ to
     become up to 10% faster.

   - bpo-31170(12): expat: Update libexpat from 2.2.3 to 2.2.4.  Fix
     copying of partial characters for UTF-8 input (libexpat bug 115):
     ‘https://github.com/libexpat/libexpat/issues/115’

   - bpo-29136(13): Add TLS 1.3 cipher suites and OP_NO_TLSv1_3.

   - bpo-29212(14): Fix concurrent.futures.thread.ThreadPoolExecutor
     threads to have a non repr() based thread name by default when no
     thread_name_prefix is supplied.  They will now identify themselves
     as “ThreadPoolExecutor-y_n”.

   - bpo-9146(15): Fix a segmentation fault in _hashopenssl when
     standard hash functions such as md5 are not available in the linked
     OpenSSL library.  As in some special FIPS-140 build environments.

   - bpo-27144(16): The ‘map()’ and ‘as_completed()’ iterators in
     ‘concurrent.futures’ now avoid keeping a reference to yielded
     objects.

   - bpo-10746(17): Fix ctypes producing wrong PEP 3118(18) type codes
     for integer types.

   - bpo-22536(19): The subprocess module now sets the filename when
     FileNotFoundError is raised on POSIX systems due to the executable
     or cwd not being found.

   - bpo-31249(20): concurrent.futures: WorkItem.run() used by
     ThreadPoolExecutor now breaks a reference cycle between an
     exception object and the WorkItem object.

   - bpo-31247(21): xmlrpc.server now explicitly breaks reference cycles
     when using sys.exc_info() in code handling exceptions.

   - bpo-30102(22): The ssl and hashlib modules now call
     OPENSSL_add_all_algorithms_noconf() on OpenSSL < 1.1.0.  The
     function detects CPU features and enables optimizations on some CPU
     architectures such as POWER8.  Patch is based on research from
     Gustavo Serra Scalet.

   - bpo-31185(23): Fixed miscellaneous errors in asyncio speedup
     module.

   - bpo-31135(24): ttk: fix the destroy() method of LabeledScale and
     OptionMenu classes.  Call the parent destroy() method even if the
     used attribute doesn’t exist.  The LabeledScale.destroy() method
     now also explicitly clears label and scale attributes to help the
     garbage collector to destroy all widgets.

   - bpo-31107(25): Fix ‘copyreg._slotnames()’ mangled attribute
     calculation for classes whose name begins with an underscore.
     Patch by Shane Harvey.

   - bpo-31061(26): Fixed a crash when using asyncio and threads.

   - bpo-30502(27): Fix handling of long oids in ssl.  Based on patch by
     Christian Heimes.

   - bpo-30119(28): ftplib.FTP.putline() now throws ValueError on
     commands that contains CR or LF. Patch by Donghee Na.

   - bpo-30595(29): multiprocessing.Queue.get() with a timeout now polls
     its reader in non-blocking mode if it succeeded to acquire the lock
     but the acquire took longer than the timeout.

   - bpo-29403(30): Fix ‘unittest.mock’’s autospec to not fail on
     method-bound builtin functions.  Patch by Aaron Gallagher.

   - bpo-30961(31): Fix decrementing a borrowed reference in
     tracemalloc.

   - bpo-25684(32): Change ‘ttk.OptionMenu’ radiobuttons to be unique
     across instances of ‘OptionMenu’.

   - bpo-30886(33): Fix multiprocessing.Queue.join_thread(): it now
     waits until the thread completes, even if the thread was started by
     the same process which created the queue.

   - bpo-29854(34): Fix segfault in readline when using readline’s
     history-size option.  Patch by Nir Soffer.

   - bpo-30319(35): socket.close() now ignores ECONNRESET error.

   - bpo-30828(36): Fix out of bounds write in
     ‘asyncio.CFuture.remove_done_callback()’.

   - bpo-30807(37): signal.setitimer() may disable the timer when passed
     a tiny value.  Tiny values (such as 1e-6) are valid non-zero values
     for setitimer(), which is specified as taking
     microsecond-resolution intervals.  However, on some platform, our
     conversion routine could convert 1e-6 into a zero interval,
     therefore disabling the timer instead of (re-)scheduling it.

   - bpo-30441(38): Fix bug when modifying os.environ while iterating
     over it

   - bpo-30532(39): Fix email header value parser dropping folding white
     space in certain cases.

   - bpo-30879(40): os.listdir() and os.scandir() now emit bytes names
     when called with bytes-like argument.

   - bpo-30746(41): Prohibited the ‘=’ character in environment variable
     names in ‘os.putenv()’ and ‘os.spawn*()’.

   - bpo-29755(42): Fixed the lgettext() family of functions in the
     gettext module.  They now always return bytes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31499

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31544

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31234

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31457

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31400

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28958

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27340

   (10) https://bugs.python.org/issue?@action=redirect&bpo=31178

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31350

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31170

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29136

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29212

   (15) https://bugs.python.org/issue?@action=redirect&bpo=9146

   (16) https://bugs.python.org/issue?@action=redirect&bpo=27144

   (17) https://bugs.python.org/issue?@action=redirect&bpo=10746

   (18) https://peps.python.org/pep-3118/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=22536

   (20) https://bugs.python.org/issue?@action=redirect&bpo=31249

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31247

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30102

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31185

   (24) https://bugs.python.org/issue?@action=redirect&bpo=31135

   (25) https://bugs.python.org/issue?@action=redirect&bpo=31107

   (26) https://bugs.python.org/issue?@action=redirect&bpo=31061

   (27) https://bugs.python.org/issue?@action=redirect&bpo=30502

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30119

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30595

   (30) https://bugs.python.org/issue?@action=redirect&bpo=29403

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30961

   (32) https://bugs.python.org/issue?@action=redirect&bpo=25684

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30886

   (34) https://bugs.python.org/issue?@action=redirect&bpo=29854

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30319

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30828

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30807

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30441

   (39) https://bugs.python.org/issue?@action=redirect&bpo=30532

   (40) https://bugs.python.org/issue?@action=redirect&bpo=30879

   (41) https://bugs.python.org/issue?@action=redirect&bpo=30746

   (42) https://bugs.python.org/issue?@action=redirect&bpo=29755


File: python.info,  Node: Documentation<68>,  Next: Tests<69>,  Prev: Library<154>,  Up: Python 3 6 3 release candidate 1

1.23.82.4 Documentation
.......................

   - bpo-31294(1): Fix incomplete code snippet in the
     ZeroMQSocketListener and ZeroMQSocketHandler examples and adapt
     them to Python 3.

   - bpo-21649(2): Add RFC 7525 and Mozilla server side TLS links to SSL
     documentation.

   - bpo-30803(3): Clarify doc on truth value testing.  Original patch
     by Peter Thomassen.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31294

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21649

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30803


File: python.info,  Node: Tests<69>,  Next: Build<75>,  Prev: Documentation<68>,  Up: Python 3 6 3 release candidate 1

1.23.82.5 Tests
...............

   - bpo-31320(1): Silence traceback in test_ssl

   - bpo-25674(2): Remove sha256.tbs-internet.com ssl test

   - bpo-30715(3): Address ALPN callback changes for OpenSSL 1.1.0f.
     The latest version behaves like OpenSSL 1.0.2 and no longer aborts
     handshake.

   - bpo-30822(4): regrtest: Exclude tzdata from regrtest –all.  When
     running the test suite using –use=all / -u all, exclude tzdata
     since it makes test_datetime too slow (15-20 min on some buildbots)
     which then times out on some buildbots.  Fix also regrtest command
     line parser to allow passing -u extralargefile to run
     test_zipfile64.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31320

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25674

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30715

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30822


File: python.info,  Node: Build<75>,  Next: Windows<65>,  Prev: Tests<69>,  Up: Python 3 6 3 release candidate 1

1.23.82.6 Build
...............

   - bpo-30854(1): Fix compile error when compiling –without-threads.
     Patch by Masayuki Yamamoto.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30854


File: python.info,  Node: Windows<65>,  Next: IDLE<53>,  Prev: Build<75>,  Up: Python 3 6 3 release candidate 1

1.23.82.7 Windows
.................

   - bpo-30389(1): Adds detection of Visual Studio 2017 to distutils on
     Windows.

   - bpo-31340(2): Change to building with MSVC v141 (included with
     Visual Studio 2017)

   - bpo-30581(3): os.cpu_count() now returns the correct number of
     processors on Windows when the number of logical processors is
     greater than 64.

   - bpo-30731(4): Add a missing xmlns to python.manifest so that it
     matches the schema.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30389

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31340

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30581

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30731


File: python.info,  Node: IDLE<53>,  Next: Tools/Demos<40>,  Prev: Windows<65>,  Up: Python 3 6 3 release candidate 1

1.23.82.8 IDLE
..............

   - bpo-31493(1): IDLE code context – fix code update and font update
     timers.  Canceling timers prevents a warning message when test_idle
     completes.

   - bpo-31488(2): IDLE - Update non-key options in former extension
     classes.  When applying configdialog changes, call .reload for each
     feature class.  Change ParenMatch so updated options affect
     existing instances attached to existing editor windows.

   - bpo-31477(3): IDLE - Improve rstrip entry in doc.  Strip trailing
     whitespace strips more than blank spaces.  Multiline string
     literals are not skipped.

   - bpo-31480(4): IDLE - make tests pass with zzdummy extension
     disabled by default.

   - bpo-31421(5): Document how IDLE runs tkinter programs.  IDLE calls
     tcl/tk update in the background in order to make live interaction
     and experimentation with tkinter applications much easier.

   - bpo-31414(6): IDLE – fix tk entry box tests by deleting first.
     Adding to an int entry is not the same as deleting and inserting
     because int(‘’) will fail.

   - bpo-31051(7): Rearrange IDLE configdialog GenPage into Window,
     Editor, and Help sections.

   - bpo-30617(8): IDLE - Add docstrings and tests for outwin subclass
     of editor.  Move some data and functions from the class to module
     level.  Patch by Cheryl Sabella.

   - bpo-31287(9): IDLE - Do not modify tkinter.message in
     test_configdialog.

   - bpo-27099(10): Convert IDLE’s built-in ‘extensions’ to regular
     features.  About 10 IDLE features were implemented as supposedly
     optional extensions.  Their different behavior could be confusing
     or worse for users and not good for maintenance.  Hence the
     conversion.  The main difference for users is that user
     configurable key bindings for builtin features are now handled
     uniformly.  Now, editing a binding in a keyset only affects its
     value in the keyset.  All bindings are defined together in the
     system-specific default keysets in config-extensions.def.  All
     custom keysets are saved as a whole in config-extension.cfg.  All
     take effect as soon as one clicks Apply or Ok.  The affected events
     are ‘<<force-open-completions>>’, ‘<<expand-word>>’,
     ‘<<force-open-calltip>>’, ‘<<flash-paren>>’,
     ‘<<format-paragraph>>’, ‘<<run-module>>’, ‘<<check-module>>’, and
     ‘<<zoom-height>>’.  Any (global) customizations made before 3.6.3
     will not affect their keyset-specific customization after 3.6.3.
     and vice versa.  Initial patch by Charles Wohlganger.

   - bpo-31206(11): IDLE: Factor HighPage(Frame) class from
     ConfigDialog.  Patch by Cheryl Sabella.

   - bpo-31001(12): Add tests for configdialog highlight tab.  Patch by
     Cheryl Sabella.

   - bpo-31205(13): IDLE: Factor KeysPage(Frame) class from
     ConfigDialog.  The slightly modified tests continue to pass.  Patch
     by Cheryl Sabella.

   - bpo-31130(14): IDLE – stop leaks in test_configdialog.  Initial
     patch by Victor Stinner.

   - bpo-31002(15): Add tests for configdialog keys tab.  Patch by
     Cheryl Sabella.

   - bpo-19903(16): IDLE: Calltips use ‘inspect.signature’ instead of
     ‘inspect.getfullargspec’.  This improves calltips for builtins
     converted to use Argument Clinic.  Patch by Louie Lu.

   - bpo-31083(17): IDLE - Add an outline of a TabPage class in
     configdialog.  Update existing classes to match outline.  Initial
     patch by Cheryl Sabella.

   - bpo-31050(18): Factor GenPage(Frame) class from ConfigDialog.  The
     slightly modified tests continue to pass.  Patch by Cheryl Sabella.

   - bpo-31004(19): IDLE - Factor FontPage(Frame) class from
     ConfigDialog.  Slightly modified tests continue to pass.  Fix
     General tests.  Patch mostly by Cheryl Sabella.

   - bpo-30781(20): IDLE - Use ttk widgets in ConfigDialog.  Patches by
     Terry Jan Reedy and Cheryl Sabella.

   - bpo-31060(21): IDLE - Finish rearranging methods of ConfigDialog
     Grouping methods pertaining to each tab and the buttons will aid
     writing tests and improving the tabs and will enable splitting the
     groups into classes.

   - bpo-30853(22): IDLE – Factor a VarTrace class out of ConfigDialog.
     Instance tracers manages pairs consisting of a tk variable and a
     callback function.  When tracing is turned on, setting the variable
     calls the function.  Test coverage for the new class is 100%.

   - bpo-31003(23): IDLE: Add more tests for General tab.

   - bpo-30993(24): IDLE - Improve configdialog font page and tests.  In
     configdialog: Document causal pathways in create_font_tab
     docstring.  Simplify some attribute names.  Move set_samples calls
     to var_changed_font (idea from Cheryl Sabella).  Move related
     functions to positions after the create widgets function.  In
     test_configdialog: Fix test_font_set so not order dependent.  Fix
     renamed test_indent_scale so it tests the widget.  Adjust tests for
     movement of set_samples call.  Add tests for load functions.  Put
     all font tests in one class and tab indent tests in another.
     Except for two lines, these tests completely cover the related
     functions.

   - bpo-30981(25): IDLE – Add more configdialog font page tests.

   - bpo-28523(26): IDLE: replace ‘colour’ with ‘color’ in configdialog.

   - bpo-30917(27): Add tests for idlelib.config.IdleConf.  Increase
     coverage from 46% to 96%.  Patch by Louie Lu.

   - bpo-30934(28): Document coverage details for idlelib tests.  Add
     section to idlelib/idle-test/README.txt.  Include check that
     branches are taken both ways.  Exclude IDLE-specific code that does
     not run during unit tests.

   - bpo-30913(29): IDLE: Document ConfigDialog tk Vars, methods, and
     widgets in docstrings This will facilitate improving the dialog and
     splitting up the class.  Original patch by Cheryl Sabella.

   - bpo-30899(30): IDLE: Add tests for ConfigParser subclasses in
     config.  Patch by Louie Lu.

   - bpo-30881(31): IDLE: Add docstrings to browser.py.  Patch by Cheryl
     Sabella.

   - bpo-30851(32): IDLE: Remove unused variables in configdialog.  One
     is a duplicate, one is set but cannot be altered by users.  Patch
     by Cheryl Sabella.

   - bpo-30870(33): IDLE: In Settings dialog, select font with Up, Down
     keys as well as mouse.  Initial patch by Louie Lu.

   - bpo-8231(34): IDLE: call config.IdleConf.GetUserCfgDir only once.

   - bpo-30779(35): IDLE: Factor ConfigChanges class from configdialog,
     put in config; test.  * In config, put dump test code in a
     function; run it and unittest in ‘if __name__ == ‘__main__’.  * Add
     class config.ConfigChanges based on changes_class_v4.py on bpo
     issue.  * Add class test_config.ChangesTest, partly using
     configdialog_tests_v1.py.  * Revise configdialog to use
     ConfigChanges; see tracker msg297804.  * Revise test_configdialog
     to match configdialog changes.  * Remove configdialog functions
     unused or moved to ConfigChanges.  Cheryl Sabella contributed parts
     of the patch.

   - bpo-30777(36): IDLE: configdialog - Add docstrings and fix
     comments.  Patch by Cheryl Sabella.

   - bpo-30495(37): IDLE: Improve textview with docstrings, PEP8 names,
     and more tests.  Patch by Cheryl Sabella.

   - bpo-30723(38): IDLE: Make several improvements to parenmatch.  Add
     ‘parens’ style to highlight both opener and closer.  Make ‘default’
     style, which is not default, a synonym for ‘opener’.  Make
     time-delay work the same with all styles.  Add help for config
     dialog extensions tab, including help for parenmatch.  Add new
     tests.  Original patch by Charles Wohlganger.

   - bpo-30674(39): IDLE: add docstrings to grep module.  Patch by
     Cheryl Sabella

   - bpo-21519(40): IDLE’s basic custom key entry dialog now detects
     duplicates properly.  Original patch by Saimadhav Heblikar.

   - bpo-29910(41): IDLE no longer deletes a character after commenting
     out a region by a key shortcut.  Add ‘return 'break'’ for this and
     other potential conflicts between IDLE and default key bindings.

   - bpo-30728(42): Review and change idlelib.configdialog names.
     Lowercase method and attribute names.  Replace ‘colour’ with
     ‘color’, expand overly cryptic names, delete unneeded underscores.
     Replace ‘import *’ with specific imports.  Patches by Cheryl
     Sabella.

   - bpo-6739(43): IDLE: Verify user-entered key sequences by trying to
     bind them with tk.  Add tests for all 3 validation functions.
     Original patch by G Polo.  Tests added by Cheryl Sabella.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31493

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31488

   (3) https://bugs.python.org/issue?@action=redirect&bpo=31477

   (4) https://bugs.python.org/issue?@action=redirect&bpo=31480

   (5) https://bugs.python.org/issue?@action=redirect&bpo=31421

   (6) https://bugs.python.org/issue?@action=redirect&bpo=31414

   (7) https://bugs.python.org/issue?@action=redirect&bpo=31051

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30617

   (9) https://bugs.python.org/issue?@action=redirect&bpo=31287

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27099

   (11) https://bugs.python.org/issue?@action=redirect&bpo=31206

   (12) https://bugs.python.org/issue?@action=redirect&bpo=31001

   (13) https://bugs.python.org/issue?@action=redirect&bpo=31205

   (14) https://bugs.python.org/issue?@action=redirect&bpo=31130

   (15) https://bugs.python.org/issue?@action=redirect&bpo=31002

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19903

   (17) https://bugs.python.org/issue?@action=redirect&bpo=31083

   (18) https://bugs.python.org/issue?@action=redirect&bpo=31050

   (19) https://bugs.python.org/issue?@action=redirect&bpo=31004

   (20) https://bugs.python.org/issue?@action=redirect&bpo=30781

   (21) https://bugs.python.org/issue?@action=redirect&bpo=31060

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30853

   (23) https://bugs.python.org/issue?@action=redirect&bpo=31003

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30993

   (25) https://bugs.python.org/issue?@action=redirect&bpo=30981

   (26) https://bugs.python.org/issue?@action=redirect&bpo=28523

   (27) https://bugs.python.org/issue?@action=redirect&bpo=30917

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30934

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30913

   (30) https://bugs.python.org/issue?@action=redirect&bpo=30899

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30881

   (32) https://bugs.python.org/issue?@action=redirect&bpo=30851

   (33) https://bugs.python.org/issue?@action=redirect&bpo=30870

   (34) https://bugs.python.org/issue?@action=redirect&bpo=8231

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30779

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30777

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30495

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30723

   (39) https://bugs.python.org/issue?@action=redirect&bpo=30674

   (40) https://bugs.python.org/issue?@action=redirect&bpo=21519

   (41) https://bugs.python.org/issue?@action=redirect&bpo=29910

   (42) https://bugs.python.org/issue?@action=redirect&bpo=30728

   (43) https://bugs.python.org/issue?@action=redirect&bpo=6739


File: python.info,  Node: Tools/Demos<40>,  Prev: IDLE<53>,  Up: Python 3 6 3 release candidate 1

1.23.82.9 Tools/Demos
.....................

   - bpo-30983(1): gdb integration commands (py-bt, etc.)  work on
     optimized shared builds now, too.  PEP 523(2) introduced
     _PyEval_EvalFrameDefault which inlines PyEval_EvalFrameEx on
     non-debug shared builds.  This broke the ability to use py-bt,
     py-up, and a few other Python-specific gdb integrations.  The
     problem is fixed by only looking for _PyEval_EvalFrameDefault
     frames in python-gdb.py.  Original patch by Bruno “Polaco”
     Penteado.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30983

   (2) https://peps.python.org/pep-0523/


File: python.info,  Node: Python 3 6 2 final,  Next: Python 3 6 2 release candidate 2,  Prev: Python 3 6 3 release candidate 1,  Up: Changelog

1.23.83 Python 3.6.2 final
--------------------------

'Release date: 2017-07-17'

No changes since release candidate 2


File: python.info,  Node: Python 3 6 2 release candidate 2,  Next: Python 3 6 2 release candidate 1,  Prev: Python 3 6 2 final,  Up: Changelog

1.23.84 Python 3.6.2 release candidate 2
----------------------------------------

'Release date: 2017-07-07'

* Menu:

* Security: Security<49>.


File: python.info,  Node: Security<49>,  Up: Python 3 6 2 release candidate 2

1.23.84.1 Security
..................

   - bpo-30730(1): Prevent environment variables injection in subprocess
     on Windows.  Prevent passing other environment variables and
     command arguments.

   - bpo-30694(2): Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes
     of multiple security vulnerabilities including: CVE 2017-9233(3)
     (External entity infinite loop DoS), CVE 2016-9063(4) (Integer
     overflow, re-fix), CVE 2016-0718(5) (Fix regression bugs from
     2.2.0’s fix to CVE 2016-0718(6)) and CVE 2012-0876(7) (Counter hash
     flooding with SipHash).  Note: the CVE 2016-5300(8) (Use
     os-specific entropy sources like getrandom) doesn’t impact Python,
     since Python already gets entropy from the OS to set the expat
     secret using ‘XML_SetHashSalt()’.

   - bpo-30500(9): Fix urllib.parse.splithost() to correctly parse
     fragments.  For example, ‘splithost('//127.0.0.1#@evil.com/')’ now
     correctly returns the ‘127.0.0.1’ host, instead of treating
     ‘@evil.com’ as the host in an authentication (‘login@host’).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30730

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30694

   (3) https://www.cve.org/CVERecord?id=CVE-2017-9233

   (4) https://www.cve.org/CVERecord?id=CVE-2016-9063

   (5) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (6) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (7) https://www.cve.org/CVERecord?id=CVE-2012-0876

   (8) https://www.cve.org/CVERecord?id=CVE-2016-5300

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30500


File: python.info,  Node: Python 3 6 2 release candidate 1,  Next: Python 3 6 1 final,  Prev: Python 3 6 2 release candidate 2,  Up: Changelog

1.23.85 Python 3.6.2 release candidate 1
----------------------------------------

'Release date: 2017-06-17'

* Menu:

* Security: Security<50>.
* Core and Builtins: Core and Builtins<151>.
* Library: Library<155>.
* IDLE: IDLE<54>.
* C API: C API<66>.
* Build: Build<76>.
* Documentation: Documentation<69>.
* Tools/Demos: Tools/Demos<41>.
* Tests: Tests<70>.
* Windows: Windows<66>.


File: python.info,  Node: Security<50>,  Next: Core and Builtins<151>,  Up: Python 3 6 2 release candidate 1

1.23.85.1 Security
..................

   - bpo-29591(1): Update expat copy from 2.1.1 to 2.2.0 to get fixes of
     CVE 2016-0718(2) and CVE 2016-4472(3).  See
     ‘https://sourceforge.net/p/expat/bugs/537/’ for more information.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29591

   (2) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (3) https://www.cve.org/CVERecord?id=CVE-2016-4472


File: python.info,  Node: Core and Builtins<151>,  Next: Library<155>,  Prev: Security<50>,  Up: Python 3 6 2 release candidate 1

1.23.85.2 Core and Builtins
...........................

   - bpo-30682(1): Removed a too-strict assertion that failed for
     certain f-strings, such as eval(“f’\n’”) and eval(“f’\r’”).

   - bpo-30604(2): Move co_extra_freefuncs to not be per-thread to avoid
     crashes

   - bpo-29104(3): Fixed parsing backslashes in f-strings.

   - bpo-27945(4): Fixed various segfaults with dict when input
     collections are mutated during searching, inserting or comparing.
     Based on patches by Duane Griffin and Tim Mitchell.

   - bpo-25794(5): Fixed type.__setattr__() and type.__delattr__() for
     non-interned attribute names.  Based on patch by Eryk Sun.

   - bpo-30039(6): If a KeyboardInterrupt happens when the interpreter
     is in the middle of resuming a chain of nested ‘yield from’ or
     ‘await’ calls, it’s now correctly delivered to the innermost frame.

   - bpo-12414(7): sys.getsizeof() on a code object now returns the
     sizes which includes the code struct and sizes of objects which it
     references.  Patch by Donghee Na.

   - bpo-29949(8): Fix memory usage regression of set and frozenset
     object.

   - bpo-29935(9): Fixed error messages in the index() method of tuple,
     list and deque when pass indices of wrong type.

   - bpo-29859(10): Show correct error messages when any of the
     pthread_* calls in thread_pthread.h fails.

   - bpo-28876(11): ‘bool(range)’ works even if ‘len(range)’ raises
     *note OverflowError: 888.

   - bpo-29600(12): Fix wrapping coroutine return values in
     StopIteration.

   - bpo-28856(13): Fix an oversight that %b format for bytes should
     support objects follow the buffer protocol.

   - bpo-29714(14): Fix a regression that bytes format may fail when
     containing zero bytes inside.

   - bpo-29478(15): If max_line_length=None is specified while using the
     Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30682

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30604

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29104

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27945

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25794

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30039

   (7) https://bugs.python.org/issue?@action=redirect&bpo=12414

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29949

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29935

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29859

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28876

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29600

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28856

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29714

   (15) https://bugs.python.org/issue?@action=redirect&bpo=29478


File: python.info,  Node: Library<155>,  Next: IDLE<54>,  Prev: Core and Builtins<151>,  Up: Python 3 6 2 release candidate 1

1.23.85.3 Library
.................

   - bpo-30616(1): Functional API of enum allows to create empty enums.
     Patched by Donghee Na

   - bpo-30038(2): Fix race condition between signal delivery and wakeup
     file descriptor.  Patch by Nathaniel Smith.

   - bpo-23894(3): lib2to3 now recognizes ‘rb'...'’ and ‘f'...'’
     strings.

   - bpo-23890(4): unittest.TestCase.assertRaises() now manually breaks
     a reference cycle to not keep objects alive longer than expected.

   - bpo-30149(5): inspect.signature() now supports callables with
     variable-argument parameters wrapped with partialmethod.  Patch by
     Donghee Na.

   - bpo-30645(6): Fix path calculation in imp.load_package(), fixing it
     for cases when a package is only shipped with bytecodes.  Patch by
     Alexandru Ardelean.

   - bpo-29931(7): Fixed comparison check for ipaddress.ip_interface
     objects.  Patch by Sanjay Sundaresan.

   - bpo-30605(8): re.compile() no longer raises a BytesWarning when
     compiling a bytes instance with misplaced inline modifier.  Patch
     by Roy Williams.

   - bpo-24484(9): Avoid race condition in multiprocessing cleanup
     (#2159)

   - bpo-28994(10): The traceback no longer displayed for SystemExit
     raised in a callback registered by atexit.

   - bpo-30508(11): Don’t log exceptions if Task/Future “cancel()”
     method was called.

   - bpo-28556(12): Updates to typing module: Add generic
     AsyncContextManager, add support for ContextManager on all
     versions.  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

   - bpo-29870(13): Fix ssl sockets leaks when connection is aborted in
     asyncio/ssl implementation.  Patch by Michaël Sghaïer.

   - bpo-29743(14): Closing transport during handshake process leaks
     open socket.  Patch by Nikolay Kim

   - bpo-27585(15): Fix waiter cancellation in asyncio.Lock.  Patch by
     Mathieu Sornay.

   - bpo-30418(16): On Windows, subprocess.Popen.communicate() now also
     ignore EINVAL on stdin.write() if the child process is still
     running but closed the pipe.

   - bpo-29822(17): inspect.isabstract() now works during
     __init_subclass__.  Patch by Nate Soares.

   - bpo-29581(18): ABCMeta.__new__ now accepts ‘**kwargs’, allowing
     abstract base classes to use keyword parameters in
     __init_subclass__.  Patch by Nate Soares.

   - bpo-30557(19): faulthandler now correctly filters and displays
     exception codes on Windows

   - bpo-30378(20): Fix the problem that logging.handlers.SysLogHandler
     cannot handle IPv6 addresses.

   - bpo-29960(21): Preserve generator state when
     _random.Random.setstate() raises an exception.  Patch by Bryan
     Olson.

   - bpo-30414(22): multiprocessing.Queue._feed background running
     thread do not break from main loop on exception.

   - bpo-30003(23): Fix handling escape characters in HZ codec.  Based
     on patch by Ma Lin.

   - bpo-30301(24): Fix AttributeError when using SimpleQueue.empty()
     under 'spawn' and 'forkserver' start methods.

   - bpo-30329(25): imaplib and poplib now catch the Windows socket
     WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
     operation was attempted.  This error occurs sometimes on SSL
     connections.

   - bpo-30375(26): Warnings emitted when compile a regular expression
     now always point to the line in the user code.  Previously they
     could point into inners of the re module if emitted from inside of
     groups or conditionals.

   - bpo-30048(27): Fixed ‘Task.cancel()’ can be ignored when the task
     is running coroutine and the coroutine returned without any more
     ‘await’.

   - bpo-30266(28): contextlib.AbstractContextManager now supports
     anti-registration by setting __enter__ = None or __exit__ = None,
     following the pattern introduced in bpo-25958(29).  Patch by Jelle
     Zijlstra.

   - bpo-30298(30): Weaken the condition of deprecation warnings for
     inline modifiers.  Now allowed several subsequential inline
     modifiers at the start of the pattern (e.g.  ‘'(?i)(?s)...'’).  In
     verbose mode whitespaces and comments now are allowed before and
     between inline modifiers (e.g.  ‘'(?x) (?i) (?s)...'’).

   - bpo-29990(31): Fix range checking in GB18030 decoder.  Original
     patch by Ma Lin.

   - bpo-26293(32): Change resulted because of zipfile breakage.  (See
     also: bpo-29094(33))

   - bpo-30243(34): Removed the __init__ methods of _json’s scanner and
     encoder.  Misusing them could cause memory leaks or crashes.  Now
     scanner and encoder objects are completely initialized in the
     __new__ methods.

   - bpo-30185(35): Avoid KeyboardInterrupt tracebacks in forkserver
     helper process when Ctrl-C is received.

   - bpo-28556(36): Various updates to typing module: add
     typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes.
     Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

   - bpo-30205(37): Fix getsockname() for unbound AF_UNIX sockets on
     Linux.

   - bpo-30070(38): Fixed leaks and crashes in errors handling in the
     parser module.

   - bpo-30061(39): Fixed crashes in IOBase methods __next__() and
     readlines() when readline() or __next__() respectively return
     non-sizeable object.  Fixed possible other errors caused by not
     checking results of PyObject_Size(), PySequence_Size(), or
     PyMapping_Size().

   - bpo-30017(40): Allowed calling the close() method of the zip entry
     writer object multiple times.  Writing to a closed writer now
     always produces a ValueError.

   - bpo-30068(41): _io._IOBase.readlines will check if it’s closed
     first when hint is present.

   - bpo-29694(42): Fixed race condition in pathlib mkdir with flags
     parents=True.  Patch by Armin Rigo.

   - bpo-29692(43): Fixed arbitrary unchaining of RuntimeError
     exceptions in contextlib.contextmanager.  Patch by Siddharth
     Velankar.

   - bpo-29998(44): Pickling and copying ImportError now preserves name
     and path attributes.

   - bpo-29953(45): Fixed memory leaks in the replace() method of
     datetime and time objects when pass out of bound fold argument.

   - bpo-29942(46): Fix a crash in itertools.chain.from_iterable when
     encountering long runs of empty iterables.

   - bpo-27863(47): Fixed multiple crashes in ElementTree caused by race
     conditions and wrong types.

   - bpo-28699(48): Fixed a bug in pools in multiprocessing.pool that
     raising an exception at the very first of an iterable may swallow
     the exception or make the program hang.  Patch by Davin Potts and
     Xiang Zhang.

   - bpo-25803(49): Avoid incorrect errors raised by
     Path.mkdir(exist_ok=True) when the OS gives priority to errors such
     as EACCES over EEXIST.

   - bpo-29861(50): Release references to tasks, their arguments and
     their results as soon as they are finished in multiprocessing.Pool.

   - bpo-29884(51): faulthandler: Restore the old sigaltstack during
     teardown.  Patch by Christophe Zeitouny.

   - bpo-25455(52): Fixed crashes in repr of recursive buffered
     file-like objects.

   - bpo-29800(53): Fix crashes in partial.__repr__ if the keys of
     partial.keywords are not strings.  Patch by Michael Seifert.

   - bpo-29742(54): get_extra_info() raises exception if get called on
     closed ssl transport.  Patch by Nikolay Kim.

   - bpo-8256(55): Fixed possible failing or crashing input() if
     attributes “encoding” or “errors” of sys.stdin or sys.stdout are
     not set or are not strings.

   - bpo-28298(56): Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from
     accepting big intables (objects that have __int__) as elements.
     Patch by Oren Milman.

   - bpo-28231(57): The zipfile module now accepts path-like objects for
     external paths.

   - bpo-26915(58): index() and count() methods of
     collections.abc.Sequence now check identity before checking
     equality when do comparisons.

   - bpo-29615(59): SimpleXMLRPCDispatcher no longer chains KeyError (or
     any other exception) to exception(s) raised in the dispatched
     methods.  Patch by Petr Motejlek.

   - bpo-30177(60): path.resolve(strict=False) no longer cuts the path
     after the first element not present in the filesystem.  Patch by
     Antoine Pietri.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30616

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30038

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23894

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23890

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30149

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30645

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29931

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30605

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24484

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28994

   (11) https://bugs.python.org/issue?@action=redirect&bpo=30508

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29870

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29743

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27585

   (16) https://bugs.python.org/issue?@action=redirect&bpo=30418

   (17) https://bugs.python.org/issue?@action=redirect&bpo=29822

   (18) https://bugs.python.org/issue?@action=redirect&bpo=29581

   (19) https://bugs.python.org/issue?@action=redirect&bpo=30557

   (20) https://bugs.python.org/issue?@action=redirect&bpo=30378

   (21) https://bugs.python.org/issue?@action=redirect&bpo=29960

   (22) https://bugs.python.org/issue?@action=redirect&bpo=30414

   (23) https://bugs.python.org/issue?@action=redirect&bpo=30003

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30301

   (25) https://bugs.python.org/issue?@action=redirect&bpo=30329

   (26) https://bugs.python.org/issue?@action=redirect&bpo=30375

   (27) https://bugs.python.org/issue?@action=redirect&bpo=30048

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30266

   (29) https://bugs.python.org/issue?@action=redirect&bpo=25958

   (30) https://bugs.python.org/issue?@action=redirect&bpo=30298

   (31) https://bugs.python.org/issue?@action=redirect&bpo=29990

   (32) https://bugs.python.org/issue?@action=redirect&bpo=26293

   (33) https://bugs.python.org/issue?@action=redirect&bpo=29094

   (34) https://bugs.python.org/issue?@action=redirect&bpo=30243

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30185

   (36) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (37) https://bugs.python.org/issue?@action=redirect&bpo=30205

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30070

   (39) https://bugs.python.org/issue?@action=redirect&bpo=30061

   (40) https://bugs.python.org/issue?@action=redirect&bpo=30017

   (41) https://bugs.python.org/issue?@action=redirect&bpo=30068

   (42) https://bugs.python.org/issue?@action=redirect&bpo=29694

   (43) https://bugs.python.org/issue?@action=redirect&bpo=29692

   (44) https://bugs.python.org/issue?@action=redirect&bpo=29998

   (45) https://bugs.python.org/issue?@action=redirect&bpo=29953

   (46) https://bugs.python.org/issue?@action=redirect&bpo=29942

   (47) https://bugs.python.org/issue?@action=redirect&bpo=27863

   (48) https://bugs.python.org/issue?@action=redirect&bpo=28699

   (49) https://bugs.python.org/issue?@action=redirect&bpo=25803

   (50) https://bugs.python.org/issue?@action=redirect&bpo=29861

   (51) https://bugs.python.org/issue?@action=redirect&bpo=29884

   (52) https://bugs.python.org/issue?@action=redirect&bpo=25455

   (53) https://bugs.python.org/issue?@action=redirect&bpo=29800

   (54) https://bugs.python.org/issue?@action=redirect&bpo=29742

   (55) https://bugs.python.org/issue?@action=redirect&bpo=8256

   (56) https://bugs.python.org/issue?@action=redirect&bpo=28298

   (57) https://bugs.python.org/issue?@action=redirect&bpo=28231

   (58) https://bugs.python.org/issue?@action=redirect&bpo=26915

   (59) https://bugs.python.org/issue?@action=redirect&bpo=29615

   (60) https://bugs.python.org/issue?@action=redirect&bpo=30177


File: python.info,  Node: IDLE<54>,  Next: C API<66>,  Prev: Library<155>,  Up: Python 3 6 2 release candidate 1

1.23.85.4 IDLE
..............

   - bpo-15786(1): Fix several problems with IDLE’s autocompletion box.
     The following should now work: clicking on selection box items;
     using the scrollbar; selecting an item by hitting Return.  Hangs on
     MacOSX should no longer happen.  Patch by Louie Lu.

   - bpo-25514(2): Add doc subsubsection about IDLE failure to start.
     Popup no-connection message directs users to this section.

   - bpo-30642(3): Fix reference leaks in IDLE tests.  Patches by Louie
     Lu and Terry Jan Reedy.

   - bpo-30495(4): Add docstrings for textview.py and use PEP8 names.
     Patches by Cheryl Sabella and Terry Jan Reedy.

   - bpo-30290(5): Help-about: use pep8 names and add tests.  Increase
     coverage to 100%.  Patches by Louie Lu, Cheryl Sabella, and Terry
     Jan Reedy.

   - bpo-30303(6): Add _utest option to textview; add new tests.
     Increase coverage to 100%.  Patches by Louie Lu and Terry Jan
     Reedy.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15786

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25514

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30642

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30495

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30290

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30303


File: python.info,  Node: C API<66>,  Next: Build<76>,  Prev: IDLE<54>,  Up: Python 3 6 2 release candidate 1

1.23.85.5 C API
...............

   - bpo-27867(1): Function PySlice_GetIndicesEx() no longer replaced
     with a macro if Py_LIMITED_API is not set.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27867


File: python.info,  Node: Build<76>,  Next: Documentation<69>,  Prev: C API<66>,  Up: Python 3 6 2 release candidate 1

1.23.85.6 Build
...............

   - bpo-29941(1): Add ‘--with-assertions’ configure flag to explicitly
     enable C ‘assert()’ checks.  Defaults to off.  ‘--with-pydebug’
     implies ‘--with-assertions’.

   - bpo-28787(2): Fix out-of-tree builds of Python when configured with
     ‘--with--dtrace’.

   - bpo-29243(3): Prevent unnecessary rebuilding of Python during ‘make
     test’, ‘make install’ and some other make targets when configured
     with ‘--enable-optimizations’.

   - bpo-23404(4): Don’t regenerate generated files based on file
     modification time anymore: the action is now explicit.  Replace
     ‘make touch’ with ‘make regen-all’.

   - bpo-29643(5): Fix ‘--enable-optimization’ didn’t work.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29941

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28787

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29243

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23404

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29643


File: python.info,  Node: Documentation<69>,  Next: Tools/Demos<41>,  Prev: Build<76>,  Up: Python 3 6 2 release candidate 1

1.23.85.7 Documentation
.......................

   - bpo-30176(1): Add missing attribute related constants in curses
     documentation.

   - bpo-30052(2): the link targets for *note bytes(): 1c2. and *note
     bytearray(): 2ea. are now their respective type definitions, rather
     than the corresponding builtin function entries.  Use *note bytes:
     1c4b. and *note bytearray: 1c4c. to reference the latter.  In order
     to ensure this and future cross-reference updates are applied
     automatically, the daily documentation builds now disable the
     default output caching features in Sphinx.

   - bpo-26985(3): Add missing info of code object in inspect
     documentation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30176

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30052

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26985


File: python.info,  Node: Tools/Demos<41>,  Next: Tests<70>,  Prev: Documentation<69>,  Up: Python 3 6 2 release candidate 1

1.23.85.8 Tools/Demos
.....................

   - bpo-29367(1): python-gdb.py now supports also ‘method-wrapper’
     (‘wrapperobject’) objects.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29367


File: python.info,  Node: Tests<70>,  Next: Windows<66>,  Prev: Tools/Demos<41>,  Up: Python 3 6 2 release candidate 1

1.23.85.9 Tests
...............

   - bpo-30357(1): test_thread: setUp() now uses
     support.threading_setup() and support.threading_cleanup() to wait
     until threads complete to avoid random side effects on following
     tests.  Initial patch written by Grzegorz Grzywacz.

   - bpo-30197(2): Enhanced functions swap_attr() and swap_item() in the
     test.support module.  They now work when delete replaced attribute
     or item inside the with statement.  The old value of the attribute
     or item (or None if it doesn’t exist) now will be assigned to the
     target of the “as” clause, if there is one.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30357

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30197


File: python.info,  Node: Windows<66>,  Prev: Tests<70>,  Up: Python 3 6 2 release candidate 1

1.23.85.10 Windows
..................

   - bpo-30687(1): Locate msbuild.exe on Windows when building rather
     than vcvarsall.bat

   - bpo-30450(2): The build process on Windows no longer depends on
     Subversion, instead pulling external code from GitHub via a Python
     script.  If Python 3.6 is not found on the system (via ‘py -3.6’),
     NuGet is used to download a copy of 32-bit Python.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30687

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30450


File: python.info,  Node: Python 3 6 1 final,  Next: Python 3 6 1 release candidate 1,  Prev: Python 3 6 2 release candidate 1,  Up: Changelog

1.23.86 Python 3.6.1 final
--------------------------

'Release date: 2017-03-21'

* Menu:

* Core and Builtins: Core and Builtins<152>.
* Build: Build<77>.


File: python.info,  Node: Core and Builtins<152>,  Next: Build<77>,  Up: Python 3 6 1 final

1.23.86.1 Core and Builtins
...........................

   - bpo-29723(1): The ‘sys.path[0]’ initialization change for
     bpo-29139(2) caused a regression by revealing an inconsistency in
     how sys.path is initialized when executing ‘__main__’ from a
     zipfile, directory, or other import location.  The interpreter now
     consistently avoids ever adding the import location’s parent
     directory to ‘sys.path’, and ensures no other ‘sys.path’ entries
     are inadvertently modified when inserting the import location named
     on the command line.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29723

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29139


File: python.info,  Node: Build<77>,  Prev: Core and Builtins<152>,  Up: Python 3 6 1 final

1.23.86.2 Build
...............

   - bpo-27593(1): fix format of git information used in sys.version

   - Fix incompatible comment in python.h

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27593


File: python.info,  Node: Python 3 6 1 release candidate 1,  Next: Python 3 6 0 final,  Prev: Python 3 6 1 final,  Up: Changelog

1.23.87 Python 3.6.1 release candidate 1
----------------------------------------

'Release date: 2017-03-04'

* Menu:

* Core and Builtins: Core and Builtins<153>.
* Library: Library<156>.
* IDLE: IDLE<55>.
* Windows: Windows<67>.
* C API: C API<67>.
* Documentation: Documentation<70>.
* Tests: Tests<71>.
* Build: Build<78>.


File: python.info,  Node: Core and Builtins<153>,  Next: Library<156>,  Up: Python 3 6 1 release candidate 1

1.23.87.1 Core and Builtins
...........................

   - bpo-28893(1): Set correct __cause__ for errors about invalid
     awaitables returned from __aiter__ and __anext__.

   - bpo-29683(2): Fixes to memory allocation in _PyCode_SetExtra.
     Patch by Brian Coleman.

   - bpo-29684(3): Fix minor regression of
     PyEval_CallObjectWithKeywords.  It should raise TypeError when
     kwargs is not a dict.  But it might cause segv when args=NULL and
     kwargs is not a dict.

   - bpo-28598(4): Support __rmod__ for subclasses of str being called
     before str.__mod__.  Patch by Martijn Pieters.

   - bpo-29607(5): Fix stack_effect computation for CALL_FUNCTION_EX.
     Patch by Matthieu Dartiailh.

   - bpo-29602(6): Fix incorrect handling of signed zeros in complex
     constructor for complex subclasses and for inputs having a
     __complex__ method.  Patch by Serhiy Storchaka.

   - bpo-29347(7): Fixed possibly dereferencing undefined pointers when
     creating weakref objects.

   - bpo-29438(8): Fixed use-after-free problem in key sharing dict.

   - bpo-29319(9): Prevent RunMainFromImporter overwriting sys.path[0].

   - bpo-29337(10): Fixed possible BytesWarning when compare the code
     objects.  Warnings could be emitted at compile time.

   - bpo-29327(11): Fixed a crash when pass the iterable keyword
     argument to sorted().

   - bpo-29034(12): Fix memory leak and use-after-free in os module
     (path_converter).

   - bpo-29159(13): Fix regression in bytes(x) when x.__index__() raises
     Exception.

   - bpo-28932(14): Do not include <sys/random.h> if it does not exist.

   - bpo-25677(15): Correct the positioning of the syntax error caret
     for indented blocks.  Based on patch by Michael Layzell.

   - bpo-29000(16): Fixed bytes formatting of octals with zero padding
     in alternate form.

   - bpo-26919(17): On Android, operating system data is now always
     encoded/decoded to/from UTF-8, instead of the locale encoding to
     avoid inconsistencies with os.fsencode() and os.fsdecode() which
     are already using UTF-8.

   - bpo-28991(18): functools.lru_cache() was susceptible to an obscure
     reentrancy bug triggerable by a monkey-patched len() function.

   - bpo-28739(19): f-string expressions are no longer accepted as
     docstrings and by ast.literal_eval() even if they do not include
     expressions.

   - bpo-28512(20): Fixed setting the offset attribute of SyntaxError by
     PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

   - bpo-28918(21): Fix the cross compilation of xxlimited when Python
     has been built with Py_DEBUG defined.

   - bpo-28731(22): Optimize _PyDict_NewPresized() to create correct
     size dict.  Improve speed of dict literal with constant keys up to
     30%.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28893

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29683

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29684

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28598

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29607

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29602

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29347

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29438

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29319

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29337

   (11) https://bugs.python.org/issue?@action=redirect&bpo=29327

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29034

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29159

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28932

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25677

   (16) https://bugs.python.org/issue?@action=redirect&bpo=29000

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26919

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28991

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28739

   (20) https://bugs.python.org/issue?@action=redirect&bpo=28512

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28918

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28731


File: python.info,  Node: Library<156>,  Next: IDLE<55>,  Prev: Core and Builtins<153>,  Up: Python 3 6 1 release candidate 1

1.23.87.2 Library
.................

   - bpo-29169(1): Update zlib to 1.2.11.

   - bpo-29623(2): Allow use of path-like object as a single argument in
     ConfigParser.read().  Patch by David Ellis.

   - bpo-28963(3): Fix out of bound iteration in
     asyncio.Future.remove_done_callback implemented in C.

   - bpo-29704(4): asyncio.subprocess.SubprocessStreamProtocol no longer
     closes before all pipes are closed.

   - bpo-29271(5): Fix Task.current_task and Task.all_tasks implemented
     in C to accept None argument as their pure Python implementation.

   - bpo-29703(6): Fix asyncio to support instantiation of new event
     loops in child processes.

   - bpo-29376(7): Fix assertion error in
     threading._DummyThread.is_alive().

   - bpo-28624(8): Add a test that checks that cwd parameter of Popen()
     accepts PathLike objects.  Patch by Sayan Chowdhury.

   - bpo-28518(9): Start a transaction implicitly before a DML
     statement.  Patch by Aviv Palivoda.

   - bpo-29532(10): Altering a kwarg dictionary passed to
     functools.partial() no longer affects a partial object after
     creation.

   - bpo-29110(11): Fix file object leak in aifc.open() when file is
     given as a filesystem path and is not in valid AIFF format.  Patch
     by Anthony Zhang.

   - bpo-28556(12): Various updates to typing module: typing.Counter,
     typing.ChainMap, improved ABC caching, etc.  Original PRs by Jelle
     Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

   - bpo-29100(13): Fix datetime.fromtimestamp() regression introduced
     in Python 3.6.0: check minimum and maximum years.

   - bpo-29519(14): Fix weakref spewing exceptions during interpreter
     shutdown when used with a rare combination of multiprocessing and
     custom codecs.

   - bpo-29416(15): Prevent infinite loop in pathlib.Path.mkdir

   - bpo-29444(16): Fixed out-of-bounds buffer access in the group()
     method of the match object.  Based on patch by WGH.

   - bpo-29335(17): Fix subprocess.Popen.wait() when the child process
     has exited to a stopped instead of terminated state (ex: when under
     ptrace).

   - bpo-29290(18): Fix a regression in argparse that help messages
     would wrap at non-breaking spaces.

   - bpo-28735(19): Fixed the comparison of mock.MagickMock with
     mock.ANY.

   - bpo-29316(20): Restore the provisional status of typing module, add
     corresponding note to documentation.  Patch by Ivan L.

   - bpo-29219(21): Fixed infinite recursion in the repr of
     uninitialized ctypes.CDLL instances.

   - bpo-29011(22): Fix an important omission by adding Deque to the
     typing module.

   - bpo-28969(23): Fixed race condition in C implementation of
     functools.lru_cache.  KeyError could be raised when cached function
     with full cache was simultaneously called from different threads
     with the same uncached arguments.

   - bpo-29142(24): In urllib.request, suffixes in no_proxy environment
     variable with leading dots could match related hostnames again
     (e.g.  .b.c matches a.b.c).  Patch by Milan Oberkirch.

   - bpo-28961(25): Fix unittest.mock._Call helper: don’t ignore the
     name parameter anymore.  Patch written by Jiajun Huang.

   - bpo-29203(26): functools.lru_cache() now respects PEP 468(27) and
     preserves the order of keyword arguments.  f(a=1, b=2) is now
     cached separately from f(b=2, a=1) since both calls could
     potentially give different results.

   - bpo-15812(28): inspect.getframeinfo() now correctly shows the first
     line of a context.  Patch by Sam Breese.

   - bpo-29094(29): Offsets in a ZIP file created with extern file
     object and modes “w” and “x” now are relative to the start of the
     file.

   - bpo-29085(30): Allow random.Random.seed() to use high quality OS
     randomness rather than the pid and time.

   - bpo-29061(31): Fixed bug in secrets.randbelow() which would hang
     when given a negative input.  Patch by Brendan Donegan.

   - bpo-29079(32): Prevent infinite loop in pathlib.resolve() on
     Windows

   - bpo-13051(33): Fixed recursion errors in large or resized
     curses.textpad.Textbox.  Based on patch by Tycho Andersen.

   - bpo-29119(34): Fix weakrefs in the pure python version of
     collections.OrderedDict move_to_end() method.  Contributed by Andra
     Bogildea.

   - bpo-9770(35): curses.ascii predicates now work correctly with
     negative integers.

   - bpo-28427(36): old keys should not remove new values from
     WeakValueDictionary when collecting from another thread.

   - bpo-28923(37): Remove editor artifacts from Tix.py.

   - bpo-29055(38): Neaten-up empty population error on random.choice()
     by suppressing the upstream exception.

   - bpo-28871(39): Fixed a crash when deallocate deep ElementTree.

   - bpo-19542(40): Fix bugs in WeakValueDictionary.setdefault() and
     WeakValueDictionary.pop() when a GC collection happens in another
     thread.

   - bpo-20191(41): Fixed a crash in resource.prlimit() when passing a
     sequence that doesn’t own its elements as limits.

   - bpo-28779(42): multiprocessing.set_forkserver_preload() would crash
     the forkserver process if a preloaded module instantiated some
     multiprocessing objects such as locks.

   - bpo-28847(43): dbm.dumb now supports reading read-only files and no
     longer writes the index file when it is not changed.

   - bpo-26937(44): The chown() method of the tarfile.TarFile class does
     not fail now when the grp module cannot be imported, as for example
     on Android platforms.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29169

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29623

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28963

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29704

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29271

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29703

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29376

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28624

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28518

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29532

   (11) https://bugs.python.org/issue?@action=redirect&bpo=29110

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29100

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29519

   (15) https://bugs.python.org/issue?@action=redirect&bpo=29416

   (16) https://bugs.python.org/issue?@action=redirect&bpo=29444

   (17) https://bugs.python.org/issue?@action=redirect&bpo=29335

   (18) https://bugs.python.org/issue?@action=redirect&bpo=29290

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28735

   (20) https://bugs.python.org/issue?@action=redirect&bpo=29316

   (21) https://bugs.python.org/issue?@action=redirect&bpo=29219

   (22) https://bugs.python.org/issue?@action=redirect&bpo=29011

   (23) https://bugs.python.org/issue?@action=redirect&bpo=28969

   (24) https://bugs.python.org/issue?@action=redirect&bpo=29142

   (25) https://bugs.python.org/issue?@action=redirect&bpo=28961

   (26) https://bugs.python.org/issue?@action=redirect&bpo=29203

   (27) https://peps.python.org/pep-0468/

   (28) https://bugs.python.org/issue?@action=redirect&bpo=15812

   (29) https://bugs.python.org/issue?@action=redirect&bpo=29094

   (30) https://bugs.python.org/issue?@action=redirect&bpo=29085

   (31) https://bugs.python.org/issue?@action=redirect&bpo=29061

   (32) https://bugs.python.org/issue?@action=redirect&bpo=29079

   (33) https://bugs.python.org/issue?@action=redirect&bpo=13051

   (34) https://bugs.python.org/issue?@action=redirect&bpo=29119

   (35) https://bugs.python.org/issue?@action=redirect&bpo=9770

   (36) https://bugs.python.org/issue?@action=redirect&bpo=28427

   (37) https://bugs.python.org/issue?@action=redirect&bpo=28923

   (38) https://bugs.python.org/issue?@action=redirect&bpo=29055

   (39) https://bugs.python.org/issue?@action=redirect&bpo=28871

   (40) https://bugs.python.org/issue?@action=redirect&bpo=19542

   (41) https://bugs.python.org/issue?@action=redirect&bpo=20191

   (42) https://bugs.python.org/issue?@action=redirect&bpo=28779

   (43) https://bugs.python.org/issue?@action=redirect&bpo=28847

   (44) https://bugs.python.org/issue?@action=redirect&bpo=26937


File: python.info,  Node: IDLE<55>,  Next: Windows<67>,  Prev: Library<156>,  Up: Python 3 6 1 release candidate 1

1.23.87.3 IDLE
..............

   - bpo-29071(1): IDLE colors f-string prefixes (but not invalid ur
     prefixes).

   - bpo-28572(2): Add 10% to coverage of IDLE’s test_configdialog.
     Update and augment description of the configuration system.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29071

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28572


File: python.info,  Node: Windows<67>,  Next: C API<67>,  Prev: IDLE<55>,  Up: Python 3 6 1 release candidate 1

1.23.87.4 Windows
.................

   - bpo-29579(1): Removes readme.txt from the installer

   - bpo-29326(2): Ignores blank lines in ._pth files (Patch by Alexey
     Izbyshev)

   - bpo-28164(3): Correctly handle special console filenames (patch by
     Eryk Sun)

   - bpo-29409(4): Implement PEP 529(5) for io.FileIO (Patch by Eryk
     Sun)

   - bpo-29392(6): Prevent crash when passing invalid arguments into
     msvcrt module.

   - bpo-25778(7): winreg does not truncate string correctly (Patch by
     Eryk Sun)

   - bpo-28896(8): Deprecate WindowsRegistryFinder and disable it by
     default.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29579

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29326

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28164

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29409

   (5) https://peps.python.org/pep-0529/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29392

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25778

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28896


File: python.info,  Node: C API<67>,  Next: Documentation<70>,  Prev: Windows<67>,  Up: Python 3 6 1 release candidate 1

1.23.87.5 C API
...............

   - bpo-27867(1): Function PySlice_GetIndicesEx() is replaced with a
     macro if Py_LIMITED_API is not set or set to the value between
     0x03050400 and 0x03060000 (not including) or 0x03060100 or higher.

   - bpo-29083(2): Fixed the declaration of some public API functions.
     PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
     available in limited API. PyArg_ValidateKeywordArguments(),
     PyArg_UnpackTuple() and Py_BuildValue() were not available in
     limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

   - bpo-29058(3): All stable API extensions added after Python 3.2 are
     now available only when Py_LIMITED_API is set to the PY_VERSION_HEX
     value of the minimum Python version supporting this API.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27867

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29083

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29058


File: python.info,  Node: Documentation<70>,  Next: Tests<71>,  Prev: C API<67>,  Up: Python 3 6 1 release candidate 1

1.23.87.6 Documentation
.......................

   - bpo-28929(1): Link the documentation to its source file on GitHub.

   - bpo-25008(2): Document smtpd.py as effectively deprecated and add a
     pointer to aiosmtpd, a third-party asyncio-based replacement.

   - bpo-26355(3): Add canonical header link on each page to
     corresponding major version of the documentation.  Patch by
     Matthias Bussonnier.

   - bpo-29349(4): Fix Python 2 syntax in code for building the
     documentation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28929

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25008

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26355

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29349


File: python.info,  Node: Tests<71>,  Next: Build<78>,  Prev: Documentation<70>,  Up: Python 3 6 1 release candidate 1

1.23.87.7 Tests
...............

   - bpo-28087(1): Skip test_asyncore and test_eintr poll failures on
     macOS. Skip some tests of select.poll when running on macOS due to
     unresolved issues with the underlying system poll function on some
     macOS versions.

   - bpo-29571(2): to match the behaviour of the ‘re.LOCALE’ flag,
     test_re.test_locale_flag now uses
     ‘locale.getpreferredencoding(False)’ to determine the candidate
     encoding for the test regex (allowing it to correctly skip the test
     when the default locale encoding is a multi-byte encoding)

   - bpo-28950(3): Disallow -j0 to be combined with -T/-l in regrtest
     command line arguments.

   - bpo-28683(4): Fix the tests that bind() a unix socket and raise
     PermissionError on Android for a non-root user.

   - bpo-26939(5): Add the support.setswitchinterval() function to fix
     test_functools hanging on the Android armv7 qemu emulator.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28087

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29571

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28950

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28683

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26939


File: python.info,  Node: Build<78>,  Prev: Tests<71>,  Up: Python 3 6 1 release candidate 1

1.23.87.8 Build
...............

   - bpo-27593(1): sys.version and the platform module python_build(),
     python_branch(), and python_revision() functions now use git
     information rather than hg when building from a repo.

   - bpo-29572(2): Update Windows build and OS X installers to use
     OpenSSL 1.0.2k.

   - bpo-26851(3): Set Android compilation and link flags.

   - bpo-28768(4): Fix implicit declaration of function _setmode.  Patch
     by Masayuki Yamamoto

   - bpo-29080(5): Removes hard dependency on hg.exe from
     PCBuild/build.bat

   - bpo-23903(6): Added missed names to PC/python3.def.

   - bpo-28762(7): lockf() is available on Android API level 24, but the
     F_LOCK macro is not defined in android-ndk-r13.

   - bpo-28538(8): Fix the compilation error that occurs because
     if_nameindex() is available on Android API level 24, but the
     if_nameindex structure is not defined.

   - bpo-20211(9): Do not add the directory for installing C header
     files and the directory for installing object code libraries to the
     cross compilation search paths.  Original patch by Thomas
     Petazzoni.

   - bpo-28849(10): Do not define sys.implementation._multiarch on
     Android.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27593

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29572

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26851

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28768

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29080

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23903

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28762

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28538

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20211

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28849


File: python.info,  Node: Python 3 6 0 final,  Next: Python 3 6 0 release candidate 2,  Prev: Python 3 6 1 release candidate 1,  Up: Changelog

1.23.88 Python 3.6.0 final
--------------------------

'Release date: 2016-12-23'

No changes since release candidate 2


File: python.info,  Node: Python 3 6 0 release candidate 2,  Next: Python 3 6 0 release candidate 1,  Prev: Python 3 6 0 final,  Up: Changelog

1.23.89 Python 3.6.0 release candidate 2
----------------------------------------

'Release date: 2016-12-16'

* Menu:

* Core and Builtins: Core and Builtins<154>.
* Tools/Demos: Tools/Demos<42>.
* Windows: Windows<68>.
* Build: Build<79>.


File: python.info,  Node: Core and Builtins<154>,  Next: Tools/Demos<42>,  Up: Python 3 6 0 release candidate 2

1.23.89.1 Core and Builtins
...........................

   - bpo-28147(1): Fix a memory leak in split-table dictionaries:
     setattr() must not convert combined table into split table.  Patch
     written by INADA Naoki.

   - bpo-28990(2): Fix asyncio SSL hanging if connection is closed
     before handshake is completed.  (Patch by HoHo-Ho)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28147

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28990


File: python.info,  Node: Tools/Demos<42>,  Next: Windows<68>,  Prev: Core and Builtins<154>,  Up: Python 3 6 0 release candidate 2

1.23.89.2 Tools/Demos
.....................

   - bpo-28770(1): Fix python-gdb.py for fastcalls.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28770


File: python.info,  Node: Windows<68>,  Next: Build<79>,  Prev: Tools/Demos<42>,  Up: Python 3 6 0 release candidate 2

1.23.89.3 Windows
.................

   - bpo-28896(1): Deprecate WindowsRegistryFinder.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28896


File: python.info,  Node: Build<79>,  Prev: Windows<68>,  Up: Python 3 6 0 release candidate 2

1.23.89.4 Build
...............

   - bpo-28898(1): Prevent gdb build errors due to HAVE_LONG_LONG
     redefinition.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28898


File: python.info,  Node: Python 3 6 0 release candidate 1,  Next: Python 3 6 0 beta 4,  Prev: Python 3 6 0 release candidate 2,  Up: Changelog

1.23.90 Python 3.6.0 release candidate 1
----------------------------------------

'Release date: 2016-12-06'

* Menu:

* Core and Builtins: Core and Builtins<155>.
* Library: Library<157>.
* C API: C API<68>.
* Documentation: Documentation<71>.
* Tools/Demos: Tools/Demos<43>.


File: python.info,  Node: Core and Builtins<155>,  Next: Library<157>,  Up: Python 3 6 0 release candidate 1

1.23.90.1 Core and Builtins
...........................

   - bpo-23722(1): Rather than silently producing a class that doesn’t
     support zero-argument ‘super()’ in methods, failing to pass the new
     ‘__classcell__’ namespace entry up to ‘type.__new__’ now results in
     a ‘DeprecationWarning’ and a class that supports zero-argument
     ‘super()’.

   - bpo-28797(2): Modifying the class __dict__ inside the __set_name__
     method of a descriptor that is used inside that class no longer
     prevents calling the __set_name__ method of other descriptors.

   - bpo-28782(3): Fix a bug in the implementation ‘yield from’ when
     checking if the next instruction is YIELD_FROM. Regression
     introduced by WORDCODE (bpo-26647(4)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28797

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28782

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26647


File: python.info,  Node: Library<157>,  Next: C API<68>,  Prev: Core and Builtins<155>,  Up: Python 3 6 0 release candidate 1

1.23.90.2 Library
.................

   - bpo-27030(1): Unknown escapes in re.sub() replacement template are
     allowed again.  But they still are deprecated and will be disabled
     in 3.7.

   - bpo-28835(2): Fix a regression introduced in
     warnings.catch_warnings(): call warnings.showwarning() if it was
     overridden inside the context manager.

   - bpo-27172(3): To assist with upgrades from 2.7, the previously
     documented deprecation of ‘inspect.getfullargspec()’ has been
     reversed.  This decision may be revisited again after the Python
     2.7 branch is no longer officially supported.

   - bpo-26273(4): Add new ‘socket.TCP_CONGESTION’ (Linux 2.6.13) and
     ‘socket.TCP_USER_TIMEOUT’ (Linux 2.6.37) constants.  Patch written
     by Omar Sandoval.

   - bpo-24142(5): Reading a corrupt config file left configparser in an
     invalid state.  Original patch by Florian Höch.

   - bpo-28843(6): Fix asyncio C Task to handle exceptions
     __traceback__.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27030

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28835

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27172

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26273

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24142

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28843


File: python.info,  Node: C API<68>,  Next: Documentation<71>,  Prev: Library<157>,  Up: Python 3 6 0 release candidate 1

1.23.90.3 C API
...............

   - bpo-28808(1): PyUnicode_CompareWithASCIIString() now never raises
     exceptions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28808


File: python.info,  Node: Documentation<71>,  Next: Tools/Demos<43>,  Prev: C API<68>,  Up: Python 3 6 0 release candidate 1

1.23.90.4 Documentation
.......................

   - bpo-23722(1): The data model reference and the porting section in
     the What’s New guide now cover the additional ‘__classcell__’
     handling needed for custom metaclasses to fully support PEP 487(2)
     and zero-argument ‘super()’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (2) https://peps.python.org/pep-0487/


File: python.info,  Node: Tools/Demos<43>,  Prev: Documentation<71>,  Up: Python 3 6 0 release candidate 1

1.23.90.5 Tools/Demos
.....................

   - bpo-28023(1): Fix python-gdb.py didn’t support new dict
     implementation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28023


File: python.info,  Node: Python 3 6 0 beta 4,  Next: Python 3 6 0 beta 3,  Prev: Python 3 6 0 release candidate 1,  Up: Changelog

1.23.91 Python 3.6.0 beta 4
---------------------------

'Release date: 2016-11-21'

* Menu:

* Core and Builtins: Core and Builtins<156>.
* Library: Library<158>.
* Documentation: Documentation<72>.
* Tests: Tests<72>.
* Build: Build<80>.


File: python.info,  Node: Core and Builtins<156>,  Next: Library<158>,  Up: Python 3 6 0 beta 4

1.23.91.1 Core and Builtins
...........................

   - bpo-28532(1): Show sys.version when -V option is supplied twice.

   - bpo-27100(2): The with-statement now checks for __enter__ before it
     checks for __exit__.  This gives less confusing error messages when
     both methods are missing.  Patch by Jonathan Ellington.

   - bpo-28746(3): Fix the set_inheritable() file descriptor method on
     platforms that do not have the ioctl FIOCLEX and FIONCLEX commands.

   - bpo-26920(4): Fix not getting the locale’s charset upon
     initializing the interpreter, on platforms that do not have
     langinfo.

   - bpo-28648(5): Fixed crash in Py_DecodeLocale() in debug build on
     Mac OS X when decode astral characters.  Patch by Xiang Zhang.

   - bpo-19398(6): Extra slash no longer added to sys.path components in
     case of empty compile-time PYTHONPATH components.

   - bpo-28665(7): Improve speed of the STORE_DEREF opcode by 40%.

   - bpo-28583(8): PyDict_SetDefault didn’t combine split table when
     needed.  Patch by Xiang Zhang.

   - bpo-27243(9): Change PendingDeprecationWarning ->
     DeprecationWarning.  As it was agreed in the issue, __aiter__
     returning an awaitable should result in PendingDeprecationWarning
     in 3.5 and in DeprecationWarning in 3.6.

   - bpo-26182(10): Fix a refleak in code that raises
     DeprecationWarning.

   - bpo-28721(11): Fix asynchronous generators aclose() and athrow() to
     handle StopAsyncIteration propagation properly.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28532

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27100

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28746

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26920

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28648

   (6) https://bugs.python.org/issue?@action=redirect&bpo=19398

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28665

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28583

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27243

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26182

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28721


File: python.info,  Node: Library<158>,  Next: Documentation<72>,  Prev: Core and Builtins<156>,  Up: Python 3 6 0 beta 4

1.23.91.2 Library
.................

   - bpo-28752(1): Restored the __reduce__() methods of datetime
     objects.

   - bpo-28727(2): Regular expression patterns, _sre.SRE_Pattern objects
     created by re.compile(), become comparable (only x==y and x!=y
     operators).  This change should fix the bpo-18383(3): don’t
     duplicate warning filters when the warnings module is reloaded
     (thing usually only done in unit tests).

   - bpo-20572(4): The subprocess.Popen.wait method’s undocumented
     endtime parameter now raises a DeprecationWarning.

   - bpo-25659(5): In ctypes, prevent a crash calling the from_buffer()
     and from_buffer_copy() methods on abstract classes like Array.

   - bpo-19717(6): Makes Path.resolve() succeed on paths that do not
     exist.  Patch by Vajrasky Kok

   - bpo-28563(7): Fixed possible DoS and arbitrary code execution when
     handle plural form selections in the gettext module.  The
     expression parser now supports exact syntax supported by GNU
     gettext.

   - bpo-28387(8): Fixed possible crash in _io.TextIOWrapper deallocator
     when the garbage collector is invoked in other thread.  Based on
     patch by Sebastian Cufre.

   - bpo-28600(9): Optimize loop.call_soon.

   - bpo-28613(10): Fix get_event_loop() return the current loop if
     called from coroutines/callbacks.

   - bpo-28634(11): Fix asyncio.isfuture() to support unittest.Mock.

   - bpo-26081(12): Fix refleak in _asyncio.Future.__iter__().throw.

   - bpo-28639(13): Fix inspect.isawaitable to always return bool Patch
     by Justin Mayfield.

   - bpo-28652(14): Make loop methods reject socket kinds they do not
     support.

   - bpo-28653(15): Fix a refleak in functools.lru_cache.

   - bpo-28703(16): Fix asyncio.iscoroutinefunction to handle Mock
     objects.

   - bpo-28704(17): Fix create_unix_server to support Path-like objects
     (PEP 519).

   - bpo-28720(18): Add collections.abc.AsyncGenerator.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28752

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28727

   (3) https://bugs.python.org/issue?@action=redirect&bpo=18383

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20572

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25659

   (6) https://bugs.python.org/issue?@action=redirect&bpo=19717

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28563

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28387

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28600

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28613

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28634

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26081

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28639

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28652

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28653

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28703

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28704

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28720


File: python.info,  Node: Documentation<72>,  Next: Tests<72>,  Prev: Library<158>,  Up: Python 3 6 0 beta 4

1.23.91.3 Documentation
.......................

   - bpo-28513(1): Documented command-line interface of zipfile.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28513


File: python.info,  Node: Tests<72>,  Next: Build<80>,  Prev: Documentation<72>,  Up: Python 3 6 0 beta 4

1.23.91.4 Tests
...............

   - bpo-28666(1): Now test.support.rmtree is able to remove unwritable
     or unreadable directories.

   - bpo-23839(2): Various caches now are cleared before running every
     test file.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28666

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23839


File: python.info,  Node: Build<80>,  Prev: Tests<72>,  Up: Python 3 6 0 beta 4

1.23.91.5 Build
...............

   - bpo-10656(1): Fix out-of-tree building on AIX. Patch by Tristan
     Carel and Michael Haubenwallner.

   - bpo-26359(2): Rename –with-optimiations to –enable-optimizations.

   - bpo-28676(3): Prevent missing ‘getentropy’ declaration warning on
     macOS. Patch by Gareth Rees.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=10656

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28676


File: python.info,  Node: Python 3 6 0 beta 3,  Next: Python 3 6 0 beta 2,  Prev: Python 3 6 0 beta 4,  Up: Changelog

1.23.92 Python 3.6.0 beta 3
---------------------------

'Release date: 2016-10-31'

* Menu:

* Core and Builtins: Core and Builtins<157>.
* Library: Library<159>.
* Windows: Windows<69>.
* Build: Build<81>.
* Tests: Tests<73>.


File: python.info,  Node: Core and Builtins<157>,  Next: Library<159>,  Up: Python 3 6 0 beta 3

1.23.92.1 Core and Builtins
...........................

   - bpo-28128(1): Deprecation warning for invalid str and byte escape
     sequences now prints better information about where the error
     occurs.  Patch by Serhiy Storchaka and Eric Smith.

   - bpo-28509(2): dict.update() no longer allocate unnecessary large
     memory.

   - bpo-28426(3): Fixed potential crash in PyUnicode_AsDecodedObject()
     in debug build.

   - bpo-28517(4): Fixed of-by-one error in the peephole optimizer that
     caused keeping unreachable code.

   - bpo-28214(5): Improved exception reporting for problematic
     __set_name__ attributes.

   - bpo-23782(6): Fixed possible memory leak in _PyTraceback_Add() and
     exception loss in PyTraceBack_Here().

   - bpo-28471(7): Fix “Python memory allocator called without holding
     the GIL” crash in socket.setblocking.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28128

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28509

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28426

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28517

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28214

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23782

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28471


File: python.info,  Node: Library<159>,  Next: Windows<69>,  Prev: Core and Builtins<157>,  Up: Python 3 6 0 beta 3

1.23.92.2 Library
.................

   - bpo-27517(1): LZMA compressor and decompressor no longer raise
     exceptions if given empty data twice.  Patch by Benjamin Fogle.

   - bpo-28549(2): Fixed segfault in curses’s addch() with ncurses6.

   - bpo-28449(3): tarfile.open() with mode “r” or “r:” now tries to
     open a tar file with compression before trying to open it without
     compression.  Otherwise it had 50% chance failed with
     ignore_zeros=True.

   - bpo-23262(4): The webbrowser module now supports Firefox 36+ and
     derived browsers.  Based on patch by Oleg Broytman.

   - bpo-27939(5): Fixed bugs in tkinter.ttk.LabeledScale and
     tkinter.Scale caused by representing the scale as float value
     internally in Tk.  tkinter.IntVar now works if float value is set
     to underlying Tk variable.

   - bpo-18844(6): The various ways of specifying weights for
     random.choices() now produce the same result sequences.

   - bpo-28255(7): calendar.TextCalendar().prmonth() no longer prints a
     space at the start of new line after printing a month’s calendar.
     Patch by Xiang Zhang.

   - bpo-20491(8): The textwrap.TextWrapper class now honors
     non-breaking spaces.  Based on patch by Kaarle Ritvanen.

   - bpo-28353(9): os.fwalk() no longer fails on broken links.

   - bpo-28430(10): Fix iterator of C implemented asyncio.Future doesn’t
     accept non-None value is passed to it.send(val).

   - bpo-27025(11): Generated names for Tkinter widgets now start by the
     “!” prefix for readability.

   - bpo-25464(12): Fixed HList.header_exists() in tkinter.tix module by
     addin a workaround to Tix library bug.

   - bpo-28488(13): shutil.make_archive() no longer adds entry “./” to
     ZIP archive.

   - bpo-25953(14): re.sub() now raises an error for invalid numerical
     group reference in replacement template even if the pattern is not
     found in the string.  Error message for invalid group reference now
     includes the group index and the position of the reference.  Based
     on patch by SilentGhost.

   - bpo-18219(15): Optimize csv.DictWriter for large number of columns.
     Patch by Mariatta Wijaya.

   - bpo-28448(16): Fix C implemented asyncio.Future didn’t work on
     Windows.

   - bpo-28480(17): Fix error building socket module when multithreading
     is disabled.

   - bpo-24452(18): Make webbrowser support Chrome on Mac OS X.

   - bpo-20766(19): Fix references leaked by pdb in the handling of
     SIGINT handlers.

   - bpo-28492(20): Fix how StopIteration exception is raised in
     _asyncio.Future.

   - bpo-28500(21): Fix asyncio to handle async gens GC from another
     thread.

   - bpo-26923(22): Fix asyncio.Gather to refuse being cancelled once
     all children are done.  Patch by Johannes Ebke.

   - bpo-26796(23): Don’t configure the number of workers for default
     threadpool executor.  Initial patch by Hans Lawrenz.

   - bpo-28544(24): Implement asyncio.Task in C.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27517

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28549

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28449

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23262

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27939

   (6) https://bugs.python.org/issue?@action=redirect&bpo=18844

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28255

   (8) https://bugs.python.org/issue?@action=redirect&bpo=20491

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28353

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28430

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27025

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25464

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28488

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25953

   (15) https://bugs.python.org/issue?@action=redirect&bpo=18219

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28448

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28480

   (18) https://bugs.python.org/issue?@action=redirect&bpo=24452

   (19) https://bugs.python.org/issue?@action=redirect&bpo=20766

   (20) https://bugs.python.org/issue?@action=redirect&bpo=28492

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28500

   (22) https://bugs.python.org/issue?@action=redirect&bpo=26923

   (23) https://bugs.python.org/issue?@action=redirect&bpo=26796

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28544


File: python.info,  Node: Windows<69>,  Next: Build<81>,  Prev: Library<159>,  Up: Python 3 6 0 beta 3

1.23.92.3 Windows
.................

   - bpo-28522(1): Fixes mishandled buffer reallocation in getpathp.c

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28522


File: python.info,  Node: Build<81>,  Next: Tests<73>,  Prev: Windows<69>,  Up: Python 3 6 0 beta 3

1.23.92.4 Build
...............

   - bpo-28444(1): Fix missing extensions modules when cross compiling.

   - bpo-28208(2): Update Windows build and OS X installers to use
     SQLite 3.14.2.

   - bpo-28248(3): Update Windows build and OS X installers to use
     OpenSSL 1.0.2j.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28444

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28208

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28248


File: python.info,  Node: Tests<73>,  Prev: Build<81>,  Up: Python 3 6 0 beta 3

1.23.92.5 Tests
...............

   - bpo-26944(1): Fix test_posix for Android where ‘id -G’ is entirely
     wrong or missing the effective gid.

   - bpo-28409(2): regrtest: fix the parser of command line arguments.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26944

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28409


File: python.info,  Node: Python 3 6 0 beta 2,  Next: Python 3 6 0 beta 1,  Prev: Python 3 6 0 beta 3,  Up: Changelog

1.23.93 Python 3.6.0 beta 2
---------------------------

'Release date: 2016-10-10'

* Menu:

* Core and Builtins: Core and Builtins<158>.
* Library: Library<160>.
* Windows: Windows<70>.
* C API: C API<69>.
* Build: Build<82>.
* Tests: Tests<74>.


File: python.info,  Node: Core and Builtins<158>,  Next: Library<160>,  Up: Python 3 6 0 beta 2

1.23.93.1 Core and Builtins
...........................

   - bpo-28183(1): Optimize and cleanup dict iteration.

   - bpo-26081(2): Added C implementation of asyncio.Future.  Original
     patch by Yury Selivanov.

   - bpo-28379(3): Added sanity checks and tests for
     PyUnicode_CopyCharacters().  Patch by Xiang Zhang.

   - bpo-28376(4): The type of long range iterator is now registered as
     Iterator.  Patch by Oren Milman.

   - bpo-28376(5): Creating instances of range_iterator by calling
     range_iterator type now is deprecated.  Patch by Oren Milman.

   - bpo-28376(6): The constructor of range_iterator now checks that
     step is not 0.  Patch by Oren Milman.

   - bpo-26906(7): Resolving special methods of uninitialized type now
     causes implicit initialization of the type instead of a fail.

   - bpo-18287(8): PyType_Ready() now checks that tp_name is not NULL.
     Original patch by Niklas Koep.

   - bpo-24098(9): Fixed possible crash when AST is changed in process
     of compiling it.

   - bpo-28201(10): Dict reduces possibility of 2nd conflict in hash
     table when hashes have same lower bits.

   - bpo-28350(11): String constants with null character no longer
     interned.

   - bpo-26617(12): Fix crash when GC runs during weakref callbacks.

   - bpo-27942(13): String constants now interned recursively in tuples
     and frozensets.

   - bpo-21578(14): Fixed misleading error message when ImportError
     called with invalid keyword args.

   - bpo-28203(15): Fix incorrect type in complex(1.0, {2:3}) error
     message.  Patch by Soumya Sharma.

   - bpo-28086(16): Single var-positional argument of tuple subtype was
     passed unscathed to the C-defined function.  Now it is converted to
     exact tuple.

   - bpo-28214(17): Now __set_name__ is looked up on the class instead
     of the instance.

   - bpo-27955(18): Fallback on reading /dev/urandom device when the
     getrandom() syscall fails with EPERM, for example when blocked by
     SECCOMP.

   - bpo-28192(19): Don’t import readline in isolated mode.

   - Upgrade internal unicode databases to Unicode version 9.0.0.

   - bpo-28131(20): Fix a regression in zipimport’s compile_source().
     zipimport should use the same optimization level as the
     interpreter.

   - bpo-28126(21): Replace Py_MEMCPY with memcpy().  Visual Studio can
     properly optimize memcpy().

   - bpo-28120(22): Fix dict.pop() for splitted dictionary when trying
     to remove a “pending key” (Not yet inserted in split-table).  Patch
     by Xiang Zhang.

   - bpo-26182(23): Raise DeprecationWarning when async and await
     keywords are used as variable/attribute/class/function name.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28183

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26081

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28379

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26906

   (8) https://bugs.python.org/issue?@action=redirect&bpo=18287

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24098

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28201

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28350

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26617

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27942

   (14) https://bugs.python.org/issue?@action=redirect&bpo=21578

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28203

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28086

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28214

   (18) https://bugs.python.org/issue?@action=redirect&bpo=27955

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28192

   (20) https://bugs.python.org/issue?@action=redirect&bpo=28131

   (21) https://bugs.python.org/issue?@action=redirect&bpo=28126

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28120

   (23) https://bugs.python.org/issue?@action=redirect&bpo=26182


File: python.info,  Node: Library<160>,  Next: Windows<70>,  Prev: Core and Builtins<158>,  Up: Python 3 6 0 beta 2

1.23.93.2 Library
.................

   - bpo-27998(1): Fixed bytes path support in os.scandir() on Windows.
     Patch by Eryk Sun.

   - bpo-28317(2): The disassembler now decodes FORMAT_VALUE argument.

   - bpo-26293(3): Fixed writing ZIP files that starts not from the
     start of the file.  Offsets in ZIP file now are relative to the
     start of the archive in conforming to the specification.

   - bpo-28380(4): unittest.mock Mock autospec functions now properly
     support assert_called, assert_not_called, and assert_called_once.

   - bpo-27181(5): remove statistics.geometric_mean and defer until 3.7.

   - bpo-28229(6): lzma module now supports pathlib.

   - bpo-28321(7): Fixed writing non-BMP characters with binary format
     in plistlib.

   - bpo-28225(8): bz2 module now supports pathlib.  Initial patch by
     Ethan Furman.

   - bpo-28227(9): gzip now supports pathlib.  Patch by Ethan Furman.

   - bpo-27358(10): Optimized merging var-keyword arguments and improved
     error message when passing a non-mapping as a var-keyword argument.

   - bpo-28257(11): Improved error message when passing a non-iterable
     as a var-positional argument.  Added opcode
     BUILD_TUPLE_UNPACK_WITH_CALL.

   - bpo-28322(12): Fixed possible crashes when unpickle itertools
     objects from incorrect pickle data.  Based on patch by John Leitch.

   - bpo-28228(13): imghdr now supports pathlib.

   - bpo-28226(14): compileall now supports pathlib.

   - bpo-28314(15): Fix function declaration (C flags) for the
     getiterator() method of xml.etree.ElementTree.Element.

   - bpo-28148(16): Stop using localtime() and gmtime() in the time
     module.  Introduced platform independent _PyTime_localtime API that
     is similar to POSIX localtime_r, but available on all platforms.
     Patch by Ed Schouten.

   - bpo-28253(17): Fixed calendar functions for extreme months: 0001-01
     and 9999-12.  Methods itermonthdays() and itermonthdays2() are
     reimplemented so that they don’t call itermonthdates() which can
     cause datetime.date under/overflow.

   - bpo-28275(18): Fixed possible use after free in the decompress()
     methods of the LZMADecompressor and BZ2Decompressor classes.
     Original patch by John Leitch.

   - bpo-27897(19): Fixed possible crash in
     sqlite3.Connection.create_collation() if pass invalid string-like
     object as a name.  Patch by Xiang Zhang.

   - bpo-18844(20): random.choices() now has k as a keyword-only
     argument to improve the readability of common cases and come into
     line with the signature used in other languages.

   - bpo-18893(21): Fix invalid exception handling in
     Lib/ctypes/macholib/dyld.py.  Patch by Madison May.

   - bpo-27611(22): Fixed support of default root window in the
     tkinter.tix module.  Added the master parameter in the DisplayStyle
     constructor.

   - bpo-27348(23): In the traceback module, restore the formatting of
     exception messages like “Exception: None”.  This fixes a regression
     introduced in 3.5a2.

   - bpo-25651(24): Allow false values to be used for msg parameter of
     subTest().

   - bpo-27778(25): Fix a memory leak in os.getrandom() when the
     getrandom() is interrupted by a signal and a signal handler raises
     a Python exception.

   - bpo-28200(26): Fix memory leak on Windows in the os module (fix
     path_converter() function).

   - bpo-25400(27): RobotFileParser now correctly returns default values
     for crawl_delay and request_rate.  Initial patch by Peter Wirtz.

   - bpo-27932(28): Prevent memory leak in win32_ver().

   - Fix UnboundLocalError in socket._sendfile_use_sendfile.

   - bpo-28075(29): Check for ERROR_ACCESS_DENIED in Windows
     implementation of os.stat().  Patch by Eryk Sun.

   - bpo-22493(30): Warning message emitted by using inline flags in the
     middle of regular expression now contains a (truncated) regex
     pattern.  Patch by Tim Graham.

   - bpo-25270(31): Prevent codecs.escape_encode() from raising
     SystemError when an empty bytestring is passed.

   - bpo-28181(32): Get antigravity over HTTPS. Patch by Kaartic
     Sivaraam.

   - bpo-25895(33): Enable WebSocket URL schemes in
     urllib.parse.urljoin.  Patch by Gergely Imreh and Markus
     Holtermann.

   - bpo-28114(34): Fix a crash in parse_envlist() when env contains
     byte strings.  Patch by Eryk Sun.

   - bpo-27599(35): Fixed buffer overrun in binascii.b2a_qp() and
     binascii.a2b_qp().

   - bpo-27906(36): Fix socket accept exhaustion during high TCP
     traffic.  Patch by Kevin Conway.

   - bpo-28174(37): Handle when SO_REUSEPORT isn’t properly supported.
     Patch by Seth Michael Larson.

   - bpo-26654(38): Inspect functools.partial in
     asyncio.Handle.__repr__.  Patch by iceboy.

   - bpo-26909(39): Fix slow pipes IO in asyncio.  Patch by INADA Naoki.

   - bpo-28176(40): Fix callbacks race in
     asyncio.SelectorLoop.sock_connect.

   - bpo-27759(41): Fix selectors incorrectly retain invalid file
     descriptors.  Patch by Mark Williams.

   - bpo-28368(42): Refuse monitoring processes if the child watcher has
     no loop attached.  Patch by Vincent Michel.

   - bpo-28369(43): Raise RuntimeError when transport’s FD is used with
     add_reader, add_writer, etc.

   - bpo-28370(44): Speedup asyncio.StreamReader.readexactly.  Patch by
     Коренберг Марк.

   - bpo-28371(45): Deprecate passing asyncio.Handles to
     run_in_executor.

   - bpo-28372(46): Fix asyncio to support formatting of non-python
     coroutines.

   - bpo-28399(47): Remove UNIX socket from FS before binding.  Patch by
     Коренберг Марк.

   - bpo-27972(48): Prohibit Tasks to await on themselves.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27998

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28317

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26293

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28380

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27181

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28229

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28321

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28225

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28227

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27358

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28257

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28322

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28228

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28226

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28314

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28148

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28253

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28275

   (19) https://bugs.python.org/issue?@action=redirect&bpo=27897

   (20) https://bugs.python.org/issue?@action=redirect&bpo=18844

   (21) https://bugs.python.org/issue?@action=redirect&bpo=18893

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27611

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27348

   (24) https://bugs.python.org/issue?@action=redirect&bpo=25651

   (25) https://bugs.python.org/issue?@action=redirect&bpo=27778

   (26) https://bugs.python.org/issue?@action=redirect&bpo=28200

   (27) https://bugs.python.org/issue?@action=redirect&bpo=25400

   (28) https://bugs.python.org/issue?@action=redirect&bpo=27932

   (29) https://bugs.python.org/issue?@action=redirect&bpo=28075

   (30) https://bugs.python.org/issue?@action=redirect&bpo=22493

   (31) https://bugs.python.org/issue?@action=redirect&bpo=25270

   (32) https://bugs.python.org/issue?@action=redirect&bpo=28181

   (33) https://bugs.python.org/issue?@action=redirect&bpo=25895

   (34) https://bugs.python.org/issue?@action=redirect&bpo=28114

   (35) https://bugs.python.org/issue?@action=redirect&bpo=27599

   (36) https://bugs.python.org/issue?@action=redirect&bpo=27906

   (37) https://bugs.python.org/issue?@action=redirect&bpo=28174

   (38) https://bugs.python.org/issue?@action=redirect&bpo=26654

   (39) https://bugs.python.org/issue?@action=redirect&bpo=26909

   (40) https://bugs.python.org/issue?@action=redirect&bpo=28176

   (41) https://bugs.python.org/issue?@action=redirect&bpo=27759

   (42) https://bugs.python.org/issue?@action=redirect&bpo=28368

   (43) https://bugs.python.org/issue?@action=redirect&bpo=28369

   (44) https://bugs.python.org/issue?@action=redirect&bpo=28370

   (45) https://bugs.python.org/issue?@action=redirect&bpo=28371

   (46) https://bugs.python.org/issue?@action=redirect&bpo=28372

   (47) https://bugs.python.org/issue?@action=redirect&bpo=28399

   (48) https://bugs.python.org/issue?@action=redirect&bpo=27972


File: python.info,  Node: Windows<70>,  Next: C API<69>,  Prev: Library<160>,  Up: Python 3 6 0 beta 2

1.23.93.3 Windows
.................

   - bpo-28402(1): Adds signed catalog files for stdlib on Windows.

   - bpo-28333(2): Enables Unicode for ps1/ps2 and input() prompts.
     (Patch by Eryk Sun)

   - bpo-28251(3): Improvements to help manuals on Windows.

   - bpo-28110(4): launcher.msi has different product codes between
     32-bit and 64-bit

   - bpo-28161(5): Opening CON for write access fails

   - bpo-28162(6): WindowsConsoleIO readall() fails if first line starts
     with Ctrl+Z

   - bpo-28163(7): WindowsConsoleIO fileno() passes wrong flags to
     _open_osfhandle

   - bpo-28164(8): _PyIO_get_console_type fails for various paths

   - bpo-28137(9): Renames Windows path file to ._pth

   - bpo-28138(10): Windows ._pth file should allow import site

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28402

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28333

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28251

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28110

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28161

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28162

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28163

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28164

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28137

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28138


File: python.info,  Node: C API<69>,  Next: Build<82>,  Prev: Windows<70>,  Up: Python 3 6 0 beta 2

1.23.93.4 C API
...............

   - bpo-28426(1): Deprecated undocumented functions
     PyUnicode_AsEncodedObject(), PyUnicode_AsDecodedObject(),
     PyUnicode_AsDecodedUnicode() and PyUnicode_AsEncodedUnicode().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28426


File: python.info,  Node: Build<82>,  Next: Tests<74>,  Prev: C API<69>,  Up: Python 3 6 0 beta 2

1.23.93.5 Build
...............

   - bpo-28258(1): Fixed build with Estonian locale (python-config and
     distclean targets in Makefile).  Patch by Arfrever Frehtes
     Taifersar Arahesis.

   - bpo-26661(2): setup.py now detects system libffi with multiarch
     wrapper.

   - bpo-15819(3): Remove redundant include search directory option for
     building outside the source tree.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28258

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26661

   (3) https://bugs.python.org/issue?@action=redirect&bpo=15819


File: python.info,  Node: Tests<74>,  Prev: Build<82>,  Up: Python 3 6 0 beta 2

1.23.93.6 Tests
...............

   - bpo-28217(1): Adds _testconsole module to test console input.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28217


File: python.info,  Node: Python 3 6 0 beta 1,  Next: Python 3 6 0 alpha 4,  Prev: Python 3 6 0 beta 2,  Up: Changelog

1.23.94 Python 3.6.0 beta 1
---------------------------

'Release date: 2016-09-12'

* Menu:

* Core and Builtins: Core and Builtins<159>.
* Library: Library<161>.
* IDLE: IDLE<56>.
* C API: C API<70>.
* Tests: Tests<75>.
* Build: Build<83>.
* Tools/Demos: Tools/Demos<44>.
* Windows: Windows<71>.


File: python.info,  Node: Core and Builtins<159>,  Next: Library<161>,  Up: Python 3 6 0 beta 1

1.23.94.1 Core and Builtins
...........................

   - bpo-23722(1): The __class__ cell used by zero-argument super() is
     now initialized from type.__new__ rather than __build_class__, so
     class methods relying on that will now work correctly when called
     from metaclass methods during class creation.  Patch by Martin
     Teichmann.

   - bpo-25221(2): Fix corrupted result from PyLong_FromLong(0) when
     Python is compiled with NSMALLPOSINTS = 0.

   - bpo-27080(3): Implement formatting support for PEP 515(4).  Initial
     patch by Chris Angelico.

   - bpo-27199(5): In tarfile, expose copyfileobj bufsize to improve
     throughput.  Patch by Jason Fried.

   - bpo-27948(6): In f-strings, only allow backslashes inside the
     braces (where the expressions are).  This is a breaking change from
     the 3.6 alpha releases, where backslashes are allowed anywhere in
     an f-string.  Also, require that expressions inside f-strings be
     enclosed within literal braces, and not escapes like
     ‘f'\x7b"hi"\x7d'’.

   - bpo-28046(7): Remove platform-specific directories from sys.path.

   - bpo-28071(8): Add early-out for differencing from an empty set.

   - bpo-25758(9): Prevents zipimport from unnecessarily encoding a
     filename (patch by Eryk Sun)

   - bpo-25856(10): The __module__ attribute of extension classes and
     functions now is interned.  This leads to more compact pickle data
     with protocol 4.

   - bpo-27213(11): Rework CALL_FUNCTION* opcodes to produce shorter and
     more efficient bytecode.  Patch by Demur Rumed, design by Serhiy
     Storchaka, reviewed by Serhiy Storchaka and Victor Stinner.

   - bpo-26331(12): Implement tokenizing support for PEP 515(13).  Patch
     by Georg Brandl.

   - bpo-27999(14): Make “global after use” a SyntaxError, and ditto for
     nonlocal.  Patch by Ivan Levkivskyi.

   - bpo-28003(15): Implement PEP 525(16) – Asynchronous Generators.

   - bpo-27985(17): Implement PEP 526(18) – Syntax for Variable
     Annotations.  Patch by Ivan Levkivskyi.

   - bpo-26058(19): Add a new private version to the builtin dict type,
     incremented at each dictionary creation and at each dictionary
     change.  Implementation of the PEP 509.

   - bpo-27364(20): A backslash-character pair that is not a valid
     escape sequence now generates a DeprecationWarning.  Patch by
     Emanuel Barry.

   - bpo-27350(21): ‘dict’ implementation is changed like PyPy.  It is
     more compact and preserves insertion order.  (Concept developed by
     Raymond Hettinger and patch by Inada Naoki.)

   - bpo-27911(22): Remove unnecessary error checks in
     ‘exec_builtin_or_dynamic()’.

   - bpo-27078(23): Added BUILD_STRING opcode.  Optimized f-strings
     evaluation.

   - bpo-17884(24): Python now requires systems with inttypes.h and
     stdint.h

   - bpo-27961(25): Require platforms to support ‘long long’.  Python
     hasn’t compiled without ‘long long’ for years, so this is basically
     a formality.

   - bpo-27355(26): Removed support for Windows CE. It was never
     finished, and Windows CE is no longer a relevant platform for
     Python.

   - Implement PEP 523(27).

   - bpo-27870(28): A left shift of zero by a large integer no longer
     attempts to allocate large amounts of memory.

   - bpo-25402(29): In int-to-decimal-string conversion, improve the
     estimate of the intermediate memory required, and remove an
     unnecessarily strict overflow check.  Patch by Serhiy Storchaka.

   - bpo-27214(30): In long_invert, be more careful about modifying
     object returned by long_add, and remove an unnecessary check for
     small longs.  Thanks Oren Milman for analysis and patch.

   - bpo-27506(31): Support passing the bytes/bytearray.translate()
     “delete” argument by keyword.

   - bpo-27812(32): Properly clear out a generator’s frame’s
     backreference to the generator to prevent crashes in frame.clear().

   - bpo-27811(33): Fix a crash when a coroutine that has not been
     awaited is finalized with warnings-as-errors enabled.

   - bpo-27587(34): Fix another issue found by PVS-Studio: Null pointer
     check after use of ‘def’ in _PyState_AddModule().  Initial patch by
     Christian Heimes.

   - bpo-27792(35): The modulo operation applied to ‘bool’ and other
     ‘int’ subclasses now always returns an ‘int’.  Previously the
     return type depended on the input values.  Patch by Xiang Zhang.

   - bpo-26984(36): int() now always returns an instance of exact int.

   - bpo-25604(37): Fix a minor bug in integer true division; this bug
     could potentially have caused off-by-one-ulp results on platforms
     with unreliable ldexp implementations.

   - bpo-24254(38): Make class definition namespace ordered by default.

   - bpo-27662(39): Fix an overflow check in ‘List_New’: the original
     code was checking against ‘Py_SIZE_MAX’ instead of the correct
     upper bound of ‘Py_SSIZE_T_MAX’.  Patch by Xiang Zhang.

   - bpo-27782(40): Multi-phase extension module import now correctly
     allows the ‘m_methods’ field to be used to add module level
     functions to instances of non-module types returned from
     ‘Py_create_mod’.  Patch by Xiang Zhang.

   - bpo-27936(41): The round() function accepted a second None argument
     for some types but not for others.  Fixed the inconsistency by
     accepting None for all numeric types.

   - bpo-27487(42): Warn if a submodule argument to “python -m” or
     runpy.run_module() is found in sys.modules after parent packages
     are imported, but before the submodule is executed.

   - bpo-27157(43): Make only type() itself accept the one-argument
     form.  Patch by Eryk Sun and Emanuel Barry.

   - bpo-27558(44): Fix a SystemError in the implementation of “raise”
     statement.  In a brand new thread, raise a RuntimeError since there
     is no active exception to reraise.  Patch written by Xiang Zhang.

   - bpo-28008(45): Implement PEP 530(46) – asynchronous comprehensions.

   - bpo-27942(47): Fix memory leak in codeobject.c

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23722

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25221

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27080

   (4) https://peps.python.org/pep-0515/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27199

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27948

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28046

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28071

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25758

   (10) https://bugs.python.org/issue?@action=redirect&bpo=25856

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27213

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26331

   (13) https://peps.python.org/pep-0515/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27999

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28003

   (16) https://peps.python.org/pep-0525/

   (17) https://bugs.python.org/issue?@action=redirect&bpo=27985

   (18) https://peps.python.org/pep-0526/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26058

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27364

   (21) https://bugs.python.org/issue?@action=redirect&bpo=27350

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27911

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27078

   (24) https://bugs.python.org/issue?@action=redirect&bpo=17884

   (25) https://bugs.python.org/issue?@action=redirect&bpo=27961

   (26) https://bugs.python.org/issue?@action=redirect&bpo=27355

   (27) https://peps.python.org/pep-0523/

   (28) https://bugs.python.org/issue?@action=redirect&bpo=27870

   (29) https://bugs.python.org/issue?@action=redirect&bpo=25402

   (30) https://bugs.python.org/issue?@action=redirect&bpo=27214

   (31) https://bugs.python.org/issue?@action=redirect&bpo=27506

   (32) https://bugs.python.org/issue?@action=redirect&bpo=27812

   (33) https://bugs.python.org/issue?@action=redirect&bpo=27811

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27587

   (35) https://bugs.python.org/issue?@action=redirect&bpo=27792

   (36) https://bugs.python.org/issue?@action=redirect&bpo=26984

   (37) https://bugs.python.org/issue?@action=redirect&bpo=25604

   (38) https://bugs.python.org/issue?@action=redirect&bpo=24254

   (39) https://bugs.python.org/issue?@action=redirect&bpo=27662

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27782

   (41) https://bugs.python.org/issue?@action=redirect&bpo=27936

   (42) https://bugs.python.org/issue?@action=redirect&bpo=27487

   (43) https://bugs.python.org/issue?@action=redirect&bpo=27157

   (44) https://bugs.python.org/issue?@action=redirect&bpo=27558

   (45) https://bugs.python.org/issue?@action=redirect&bpo=28008

   (46) https://peps.python.org/pep-0530/

   (47) https://bugs.python.org/issue?@action=redirect&bpo=27942


File: python.info,  Node: Library<161>,  Next: IDLE<56>,  Prev: Core and Builtins<159>,  Up: Python 3 6 0 beta 1

1.23.94.2 Library
.................

   - bpo-28732(1): Fix crash in os.spawnv() with no elements in args

   - bpo-28485(2): Always raise ValueError for negative
     compileall.compile_dir(workers=…) parameter, even when
     multithreading is unavailable.

   - bpo-28037(3): Use sqlite3_get_autocommit() instead of setting
     Connection->inTransaction manually.

   - bpo-25283(4): Attributes tm_gmtoff and tm_zone are now available on
     all platforms in the return values of time.localtime() and
     time.gmtime().

   - bpo-24454(5): Regular expression match object groups are now
     accessible using __getitem__.  “mo[x]” is equivalent to
     “mo.group(x)”.

   - bpo-10740(6): sqlite3 no longer implicitly commit an open
     transaction before DDL statements.

   - bpo-17941(7): Add a 'module' parameter to collections.namedtuple().

   - bpo-22493(8): Inline flags now should be used only at the start of
     the regular expression.  Deprecation warning is emitted if uses
     them in the middle of the regular expression.

   - bpo-26885(9): xmlrpc now supports unmarshalling additional data
     types used by Apache XML-RPC implementation for numerics and None.

   - bpo-28070(10): Fixed parsing inline verbose flag in regular
     expressions.

   - bpo-19500(11): Add client-side SSL session resumption to the ssl
     module.

   - bpo-28022(12): Deprecate ssl-related arguments in favor of
     SSLContext.  The deprecation include manual creation of SSLSocket
     and certfile/keyfile (or similar) in ftplib, httplib, imaplib,
     smtplib, poplib and urllib.

   - bpo-28043(13): SSLContext has improved default settings:
     OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_COMPRESSION,
     OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE
     and HIGH ciphers without MD5.

   - bpo-24693(14): Changed some RuntimeError’s in the zipfile module to
     more appropriate types.  Improved some error messages and debugging
     output.

   - bpo-17909(15): ‘json.load’ and ‘json.loads’ now support binary
     input encoded as UTF-8, UTF-16 or UTF-32.  Patch by Serhiy
     Storchaka.

   - bpo-27137(16): the pure Python fallback implementation of
     ‘functools.partial’ now matches the behaviour of its accelerated C
     counterpart for subclassing, pickling and text representation
     purposes.  Patch by Emanuel Barry and Serhiy Storchaka.

   - Fix possible integer overflows and crashes in the mmap module with
     unusual usage patterns.

   - bpo-1703178(17): Fix the ability to pass the –link-objects option
     to the distutils build_ext command.

   - bpo-28019(18): itertools.count() no longer rounds non-integer step
     in range between 1.0 and 2.0 to 1.

   - bpo-18401(19): Pdb now supports the ‘readrc’ keyword argument to
     control whether .pdbrc files should be read.  Patch by Martin
     Matusiak and Sam Kimbrel.

   - bpo-25969(20): Update the lib2to3 grammar to handle the unpacking
     generalizations added in 3.5.

   - bpo-14977(21): mailcap now respects the order of the lines in the
     mailcap files (“first match”), as required by RFC 1542.  Patch by
     Michael Lazar.

   - bpo-28082(22): Convert re flag constants to IntFlag.

   - bpo-28025(23): Convert all ssl module constants to IntEnum and
     IntFlags.  SSLContext properties now return flags and enums.

   - bpo-23591(24): Add Flag, IntFlag, and auto() to enum module.

   - bpo-433028(25): Added support of modifier spans in regular
     expressions.

   - bpo-24594(26): Validates persist parameter when opening MSI
     database

   - bpo-17582(27): xml.etree.ElementTree nows preserves whitespaces in
     attributes (Patch by Duane Griffin.  Reviewed and approved by
     Stefan Behnel.)

   - bpo-28047(28): Fixed calculation of line length used for the base64
     CTE in the new email policies.

   - bpo-27576(29): Fix call order in OrderedDict.__init__().

   - email.generator.DecodedGenerator now supports the policy keyword.

   - bpo-28027(30): Remove undocumented modules from ‘Lib/plat-*’: IN,
     CDROM, DLFCN, TYPES, CDIO, and STROPTS.

   - bpo-27445(31): Don’t pass str(_charset) to MIMEText.set_payload().
     Patch by Claude Paroz.

   - bpo-24277(32): The new email API is no longer provisional, and the
     docs have been reorganized and rewritten to emphasize the new API.

   - bpo-22450(33): urllib now includes an ‘Accept: */*’ header among
     the default headers.  This makes the results of REST API requests
     more consistent and predictable especially when proxy servers are
     involved.

   - lib2to3.pgen3.driver.load_grammar() now creates a stable cache file
     between runs given the same Grammar.txt input regardless of the
     hash randomization setting.

   - bpo-28005(34): Allow ImportErrors in encoding implementation to
     propagate.

   - bpo-26667(35): Support path-like objects in importlib.util.

   - bpo-27570(36): Avoid zero-length memcpy() etc calls with null
     source pointers in the “ctypes” and “array” modules.

   - bpo-22233(37): Break email header lines 'only' on the RFC specified
     CR and LF characters, not on arbitrary unicode line breaks.  This
     also fixes a bug in HTTP header parsing.

   - bpo-27331(38): The email.mime classes now all accept an optional
     policy keyword.

   - bpo-27988(39): Fix email iter_attachments incorrect mutation of
     payload list.

   - bpo-16113(40): Add SHA-3 and SHAKE support to hashlib module.

   - Eliminate a tautological-pointer-compare warning in _scproxy.c.

   - bpo-27776(41): The *note os.urandom(): 526. function does now block
     on Linux 3.17 and newer until the system urandom entropy pool is
     initialized to increase the security.  This change is part of the
     PEP 524(42).

   - bpo-27778(43): Expose the Linux ‘getrandom()’ syscall as a new
     *note os.getrandom(): ce3. function.  This change is part of the
     PEP 524(44).

   - bpo-27691(45): Fix ssl module’s parsing of GEN_RID subject
     alternative name fields in X.509 certs.

   - bpo-18844(46): Add random.choices().

   - bpo-25761(47): Improved error reporting about truncated pickle data
     in C implementation of unpickler.  UnpicklingError is now raised
     instead of AttributeError and ValueError in some cases.

   - bpo-26798(48): Add BLAKE2 (blake2b and blake2s) to hashlib.

   - bpo-26032(49): Optimized globbing in pathlib by using os.scandir();
     it is now about 1.5–4 times faster.

   - bpo-25596(50): Optimized glob() and iglob() functions in the glob
     module; they are now about 3–6 times faster.

   - bpo-27928(51): Add scrypt (password-based key derivation function)
     to hashlib module (requires OpenSSL 1.1.0).

   - bpo-27850(52): Remove 3DES from ssl module’s default cipher list to
     counter measure sweet32 attack ( CVE 2016-2183(53)).

   - bpo-27766(54): Add ChaCha20 Poly1305 to ssl module’s default cipher
     list.  (Required OpenSSL 1.1.0 or LibreSSL).

   - bpo-25387(55): Check return value of winsound.MessageBeep.

   - bpo-27866(56): Add SSLContext.get_ciphers() method to get a list of
     all enabled ciphers.

   - bpo-27744(57): Add AF_ALG (Linux Kernel crypto) to socket module.

   - bpo-26470(58): Port ssl and hashlib module to OpenSSL 1.1.0.

   - bpo-11620(59): Fix support for SND_MEMORY in winsound.PlaySound.
     Based on a patch by Tim Lesher.

   - bpo-11734(60): Add support for IEEE 754 half-precision floats to
     the struct module.  Based on a patch by Eli Stevens.

   - bpo-27919(61): Deprecated ‘extra_path’ distribution option in
     distutils packaging.

   - bpo-23229(62): Add new ‘cmath’ constants: ‘cmath.inf’ and
     ‘cmath.nan’ to match ‘math.inf’ and ‘math.nan’, and also
     ‘cmath.infj’ and ‘cmath.nanj’ to match the format used by complex
     repr.

   - bpo-27842(63): The csv.DictReader now returns rows of type
     OrderedDict.  (Contributed by Steve Holden.)

   - Remove support for passing a file descriptor to os.access.  It
     never worked but previously didn’t raise.

   - bpo-12885(64): Fix error when distutils encounters symlink.

   - bpo-27881(65): Fixed possible bugs when setting
     sqlite3.Connection.isolation_level.  Based on patch by Xiang Zhang.

   - bpo-27861(66): Fixed a crash in sqlite3.Connection.cursor() when a
     factory creates not a cursor.  Patch by Xiang Zhang.

   - bpo-19884(67): Avoid spurious output on OS X with Gnu Readline.

   - bpo-27706(68): Restore deterministic behavior of
     random.Random().seed() for string seeds using seeding version 1.
     Allows sequences of calls to random() to exactly match those
     obtained in Python 2.  Patch by Nofar Schnider.

   - bpo-10513(69): Fix a regression in Connection.commit().  Statements
     should not be reset after a commit.

   - bpo-12319(70): Chunked transfer encoding support added to
     http.client.HTTPConnection requests.  The
     urllib.request.AbstractHTTPHandler class does not enforce a
     Content-Length header any more.  If a HTTP request has a file or
     iterable body, but no Content-Length header, the library now falls
     back to use chunked transfer-encoding.

   - A new version of typing.py from ‘https://github.com/python/typing’:
     - Collection (only for 3.6) (bpo-27598(71)) - Add FrozenSet to
     __all__ (upstream #261) - fix crash in _get_type_vars() (upstream
     #259) - Remove the dict constraint in ForwardRef._eval_type
     (upstream #252)

   - bpo-27832(72): Make ‘_normalize’ parameter to ‘Fraction’
     constructor keyword-only, so that ‘Fraction(2, 3, 4)’ now raises
     ‘TypeError’.

   - bpo-27539(73): Fix unnormalised ‘Fraction.__pow__’ result in the
     case of negative exponent and negative base.

   - bpo-21718(74): cursor.description is now available for queries
     using CTEs.

   - bpo-27819(75): In distutils sdists, simply produce the “gztar”
     (gzipped tar format) distributions on all platforms unless
     “formats” is supplied.

   - bpo-2466(76): posixpath.ismount now correctly recognizes mount
     points which the user does not have permission to access.

   - bpo-9998(77): On Linux, ctypes.util.find_library now looks in
     LD_LIBRARY_PATH for shared libraries.

   - bpo-27573(78): exit message for code.interact is now configurable.

   - bpo-27930(79): Improved behaviour of
     logging.handlers.QueueListener.  Thanks to Paulo Andrade and Petr
     Viktorin for the analysis and patch.

   - bpo-6766(80): Distributed reference counting added to
     multiprocessing to support nesting of shared values / proxy
     objects.

   - bpo-21201(81): Improves readability of multiprocessing error
     message.  Thanks to Wojciech Walczak for patch.

   - asyncio: Add set_protocol / get_protocol to Transports.

   - bpo-27456(82): asyncio: Set TCP_NODELAY by default.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28732

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28485

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28037

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25283

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24454

   (6) https://bugs.python.org/issue?@action=redirect&bpo=10740

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17941

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22493

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26885

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28070

   (11) https://bugs.python.org/issue?@action=redirect&bpo=19500

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28022

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28043

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24693

   (15) https://bugs.python.org/issue?@action=redirect&bpo=17909

   (16) https://bugs.python.org/issue?@action=redirect&bpo=27137

   (17) https://bugs.python.org/issue?@action=redirect&bpo=1703178

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28019

   (19) https://bugs.python.org/issue?@action=redirect&bpo=18401

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25969

   (21) https://bugs.python.org/issue?@action=redirect&bpo=14977

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28082

   (23) https://bugs.python.org/issue?@action=redirect&bpo=28025

   (24) https://bugs.python.org/issue?@action=redirect&bpo=23591

   (25) https://bugs.python.org/issue?@action=redirect&bpo=433028

   (26) https://bugs.python.org/issue?@action=redirect&bpo=24594

   (27) https://bugs.python.org/issue?@action=redirect&bpo=17582

   (28) https://bugs.python.org/issue?@action=redirect&bpo=28047

   (29) https://bugs.python.org/issue?@action=redirect&bpo=27576

   (30) https://bugs.python.org/issue?@action=redirect&bpo=28027

   (31) https://bugs.python.org/issue?@action=redirect&bpo=27445

   (32) https://bugs.python.org/issue?@action=redirect&bpo=24277

   (33) https://bugs.python.org/issue?@action=redirect&bpo=22450

   (34) https://bugs.python.org/issue?@action=redirect&bpo=28005

   (35) https://bugs.python.org/issue?@action=redirect&bpo=26667

   (36) https://bugs.python.org/issue?@action=redirect&bpo=27570

   (37) https://bugs.python.org/issue?@action=redirect&bpo=22233

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27331

   (39) https://bugs.python.org/issue?@action=redirect&bpo=27988

   (40) https://bugs.python.org/issue?@action=redirect&bpo=16113

   (41) https://bugs.python.org/issue?@action=redirect&bpo=27776

   (42) https://peps.python.org/pep-0524/

   (43) https://bugs.python.org/issue?@action=redirect&bpo=27778

   (44) https://peps.python.org/pep-0524/

   (45) https://bugs.python.org/issue?@action=redirect&bpo=27691

   (46) https://bugs.python.org/issue?@action=redirect&bpo=18844

   (47) https://bugs.python.org/issue?@action=redirect&bpo=25761

   (48) https://bugs.python.org/issue?@action=redirect&bpo=26798

   (49) https://bugs.python.org/issue?@action=redirect&bpo=26032

   (50) https://bugs.python.org/issue?@action=redirect&bpo=25596

   (51) https://bugs.python.org/issue?@action=redirect&bpo=27928

   (52) https://bugs.python.org/issue?@action=redirect&bpo=27850

   (53) https://www.cve.org/CVERecord?id=CVE-2016-2183

   (54) https://bugs.python.org/issue?@action=redirect&bpo=27766

   (55) https://bugs.python.org/issue?@action=redirect&bpo=25387

   (56) https://bugs.python.org/issue?@action=redirect&bpo=27866

   (57) https://bugs.python.org/issue?@action=redirect&bpo=27744

   (58) https://bugs.python.org/issue?@action=redirect&bpo=26470

   (59) https://bugs.python.org/issue?@action=redirect&bpo=11620

   (60) https://bugs.python.org/issue?@action=redirect&bpo=11734

   (61) https://bugs.python.org/issue?@action=redirect&bpo=27919

   (62) https://bugs.python.org/issue?@action=redirect&bpo=23229

   (63) https://bugs.python.org/issue?@action=redirect&bpo=27842

   (64) https://bugs.python.org/issue?@action=redirect&bpo=12885

   (65) https://bugs.python.org/issue?@action=redirect&bpo=27881

   (66) https://bugs.python.org/issue?@action=redirect&bpo=27861

   (67) https://bugs.python.org/issue?@action=redirect&bpo=19884

   (68) https://bugs.python.org/issue?@action=redirect&bpo=27706

   (69) https://bugs.python.org/issue?@action=redirect&bpo=10513

   (70) https://bugs.python.org/issue?@action=redirect&bpo=12319

   (71) https://bugs.python.org/issue?@action=redirect&bpo=27598

   (72) https://bugs.python.org/issue?@action=redirect&bpo=27832

   (73) https://bugs.python.org/issue?@action=redirect&bpo=27539

   (74) https://bugs.python.org/issue?@action=redirect&bpo=21718

   (75) https://bugs.python.org/issue?@action=redirect&bpo=27819

   (76) https://bugs.python.org/issue?@action=redirect&bpo=2466

   (77) https://bugs.python.org/issue?@action=redirect&bpo=9998

   (78) https://bugs.python.org/issue?@action=redirect&bpo=27573

   (79) https://bugs.python.org/issue?@action=redirect&bpo=27930

   (80) https://bugs.python.org/issue?@action=redirect&bpo=6766

   (81) https://bugs.python.org/issue?@action=redirect&bpo=21201

   (82) https://bugs.python.org/issue?@action=redirect&bpo=27456


File: python.info,  Node: IDLE<56>,  Next: C API<70>,  Prev: Library<161>,  Up: Python 3 6 0 beta 1

1.23.94.3 IDLE
..............

   - bpo-15308(1): Add ‘interrupt execution’ (^C) to Shell menu.  Patch
     by Roger Serwy, updated by Bayard Randel.

   - bpo-27922(2): Stop IDLE tests from ‘flashing’ gui widgets on the
     screen.

   - bpo-27891(3): Consistently group and sort imports within idlelib
     modules.

   - bpo-17642(4): add larger font sizes for classroom projection.

   - Add version to title of IDLE help window.

   - bpo-25564(5): In section on IDLE – console differences, mention
     that using exec means that __builtins__ is defined for each
     statement.

   - bpo-27821(6): Fix 3.6.0a3 regression that prevented custom key sets
     from being selected when no custom theme was defined.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15308

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27922

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27891

   (4) https://bugs.python.org/issue?@action=redirect&bpo=17642

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25564

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27821


File: python.info,  Node: C API<70>,  Next: Tests<75>,  Prev: IDLE<56>,  Up: Python 3 6 0 beta 1

1.23.94.4 C API
...............

   - bpo-26900(1): Excluded underscored names and other private API from
     limited API.

   - bpo-26027(2): Add support for path-like objects in
     PyUnicode_FSConverter() & PyUnicode_FSDecoder().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26900

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26027


File: python.info,  Node: Tests<75>,  Next: Build<83>,  Prev: C API<70>,  Up: Python 3 6 0 beta 1

1.23.94.5 Tests
...............

   - bpo-27427(1): Additional tests for the math module.  Patch by
     Francisco Couzo.

   - bpo-27953(2): Skip math and cmath tests that fail on OS X 10.4 due
     to a poor libm implementation of tan.

   - bpo-26040(3): Improve test_math and test_cmath coverage and rigour.
     Patch by Jeff Allen.

   - bpo-27787(4): Call gc.collect() before checking each test for
     “dangling threads”, since the dangling threads are weak references.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27427

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27953

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26040

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27787


File: python.info,  Node: Build<83>,  Next: Tools/Demos<44>,  Prev: Tests<75>,  Up: Python 3 6 0 beta 1

1.23.94.6 Build
...............

   - bpo-27566(1): Fix clean target in freeze makefile (patch by Lisa
     Roach)

   - bpo-27705(2): Update message in validate_ucrtbase.py

   - bpo-27976(3): Deprecate building _ctypes with the bundled copy of
     libffi on non-OSX UNIX platforms.

   - bpo-27983(4): Cause lack of llvm-profdata tool when using clang as
     required for PGO linking to be a configure time error rather than
     make time when ‘--with-optimizations’ is enabled.  Also improve our
     ability to find the llvm-profdata tool on MacOS and some Linuxes.

   - bpo-21590(5): Support for DTrace and SystemTap probes.

   - bpo-26307(6): The profile-opt build now applies PGO to the built-in
     modules.

   - bpo-26359(7): Add the –with-optimizations flag to turn on LTO and
     PGO build support when available.

   - bpo-27917(8): Set platform triplets for Android builds.

   - bpo-25825(9): Update references to the $(LIBPL) installation path
     on AIX. This path was changed in 3.2a4.

   - Update OS X installer to use SQLite 3.14.1 and XZ 5.2.2.

   - bpo-21122(10): Fix LTO builds on OS X.

   - bpo-17128(11): Build OS X installer with a private copy of OpenSSL.
     Also provide a sample Install Certificates command script to
     install a set of root certificates from the third-party certifi
     module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27566

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27705

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27976

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27983

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21590

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26307

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27917

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25825

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21122

   (11) https://bugs.python.org/issue?@action=redirect&bpo=17128


File: python.info,  Node: Tools/Demos<44>,  Next: Windows<71>,  Prev: Build<83>,  Up: Python 3 6 0 beta 1

1.23.94.7 Tools/Demos
.....................

   - bpo-27952(1): Get Tools/scripts/fixcid.py working with Python 3 and
     the current “re” module, avoid invalid Python backslash escapes,
     and fix a bug parsing escaped C quote signs.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27952


File: python.info,  Node: Windows<71>,  Prev: Tools/Demos<44>,  Up: Python 3 6 0 beta 1

1.23.94.8 Windows
.................

   - bpo-28065(1): Update xz dependency to 5.2.2 and build it from
     source.

   - bpo-25144(2): Ensures TargetDir is set before continuing with
     custom install.

   - bpo-1602(3): Windows console doesn’t input or print Unicode (PEP
     528)

   - bpo-27781(4): Change file system encoding on Windows to UTF-8 (PEP
     529)

   - bpo-27731(5): Opt-out of MAX_PATH on Windows 10

   - bpo-6135(6): Adds encoding and errors parameters to subprocess.

   - bpo-27959(7): Adds oem encoding, alias ansi to mbcs, move aliasmbcs
     to codec lookup.

   - bpo-27982(8): The functions of the winsound module now accept
     keyword arguments.

   - bpo-20366(9): Build full text search support into SQLite on
     Windows.

   - bpo-27756(10): Adds new icons for Python files and processes on
     Windows.  Designs by Cherry Wang.

   - bpo-27883(11): Update sqlite to 3.14.1.0 on Windows.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28065

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25144

   (3) https://bugs.python.org/issue?@action=redirect&bpo=1602

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27781

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27731

   (6) https://bugs.python.org/issue?@action=redirect&bpo=6135

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27959

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27982

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20366

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27756

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27883


File: python.info,  Node: Python 3 6 0 alpha 4,  Next: Python 3 6 0 alpha 3,  Prev: Python 3 6 0 beta 1,  Up: Changelog

1.23.95 Python 3.6.0 alpha 4
----------------------------

'Release date: 2016-08-15'

* Menu:

* Core and Builtins: Core and Builtins<160>.
* Library: Library<162>.
* IDLE: IDLE<57>.
* Tests: Tests<76>.
* Windows: Windows<72>.
* Build: Build<84>.


File: python.info,  Node: Core and Builtins<160>,  Next: Library<162>,  Up: Python 3 6 0 alpha 4

1.23.95.1 Core and Builtins
...........................

   - bpo-27704(1): Optimized creating bytes and bytearray from byte-like
     objects and iterables.  Speed up to 3 times for short objects.
     Original patch by Naoki Inada.

   - bpo-26823(2): Large sections of repeated lines in tracebacks are
     now abbreviated as “[Previous line repeated {count} more times]” by
     the builtin traceback rendering.  Patch by Emanuel Barry.

   - bpo-27574(3): Decreased an overhead of parsing keyword arguments in
     functions implemented with using Argument Clinic.

   - bpo-22557(4): Now importing already imported modules is up to 2.5
     times faster.

   - bpo-17596(5): Include <wincrypt.h> to help with Min GW building.

   - bpo-17599(6): On Windows, rename the privately defined
     REPARSE_DATA_BUFFER structure to avoid conflicting with the
     definition from Min GW.

   - bpo-27507(7): Add integer overflow check in bytearray.extend().
     Patch by Xiang Zhang.

   - bpo-27581(8): Don’t rely on wrapping for overflow check in
     PySequence_Tuple().  Patch by Xiang Zhang.

   - bpo-1621(9): Avoid signed integer overflow in list and tuple
     operations.  Patch by Xiang Zhang.

   - bpo-27419(10): Standard __import__() no longer look up “__import__”
     in globals or builtins for importing submodules or “from import”.
     Fixed a crash if raise a warning about unabling to resolve package
     from __spec__ or __package__.

   - bpo-27083(11): Respect the PYTHONCASEOK environment variable under
     Windows.

   - bpo-27514(12): Make having too many statically nested blocks a
     SyntaxError instead of SystemError.

   - bpo-27366(13): Implemented PEP 487(14) (Simpler customization of
     class creation).  Upon subclassing, the __init_subclass__
     classmethod is called on the base class.  Descriptors are
     initialized with __set_name__ after class creation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27704

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26823

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27574

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22557

   (5) https://bugs.python.org/issue?@action=redirect&bpo=17596

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17599

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27507

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27581

   (9) https://bugs.python.org/issue?@action=redirect&bpo=1621

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27419

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27083

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27514

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27366

   (14) https://peps.python.org/pep-0487/


File: python.info,  Node: Library<162>,  Next: IDLE<57>,  Prev: Core and Builtins<160>,  Up: Python 3 6 0 alpha 4

1.23.95.2 Library
.................

   - bpo-26027(1): Add PEP 519(2)/__fspath__() support to the os and
     os.path modules.  Includes code from Jelle Zijlstra.  (See also:
     bpo-27524(3))

   - bpo-27598(4): Add Collections to collections.abc.  Patch by Ivan
     Levkivskyi, docs by Neil Girdhar.

   - bpo-25958(5): Support “anti-registration” of special methods from
     various ABCs, like __hash__, __iter__ or __len__.  All these (and
     several more) can be set to None in an implementation class and the
     behavior will be as if the method is not defined at all.
     (Previously, this mechanism existed only for __hash__, to make
     mutable classes unhashable.)  Code contributed by Andrew Barnert
     and Ivan Levkivskyi.

   - bpo-16764(6): Support keyword arguments to zlib.decompress().
     Patch by Xiang Zhang.

   - bpo-27736(7): Prevent segfault after interpreter re-initialization
     due to ref count problem introduced in code for bpo-27038(8) in
     3.6.0a3.  Patch by Xiang Zhang.

   - bpo-25628(9): The 'verbose' and 'rename' parameters for
     collections.namedtuple are now keyword-only.

   - bpo-12345(10): Add mathematical constant tau to math and cmath.
     See also PEP 628(11).

   - bpo-26823(12): traceback.StackSummary.format now abbreviates large
     sections of repeated lines as “[Previous line repeated {count} more
     times]” (this change then further affects other traceback display
     operations in the module).  Patch by Emanuel Barry.

   - bpo-27664(13): Add to
     concurrent.futures.thread.ThreadPoolExecutor() the ability to
     specify a thread name prefix.

   - bpo-27181(14): Add geometric_mean and harmonic_mean to statistics
     module.

   - bpo-27573(15): code.interact now prints an message when exiting.

   - bpo-6422(16): Add autorange method to timeit.Timer objects.

   - bpo-27773(17): Correct some memory management errors
     server_hostname in _ssl.wrap_socket().

   - bpo-26750(18): unittest.mock.create_autospec() now works properly
     for subclasses of property() and other data descriptors.  Removes
     the never publicly used, never documented
     unittest.mock.DescriptorTypes tuple.

   - bpo-26754(19): Undocumented support of general bytes-like objects
     as path in compile() and similar functions is now deprecated.

   - bpo-26800(20): Undocumented support of general bytes-like objects
     as paths in os functions is now deprecated.

   - bpo-26981(21): Add _order_ compatibility shim to enum.Enum for
     Python 2/3 code bases.

   - bpo-27661(22): Added tzinfo keyword argument to datetime.combine.

   - In the curses module, raise an error if window.getstr() or
     window.instr() is passed a negative value.

   - bpo-27783(23): Fix possible usage of uninitialized memory in
     operator.methodcaller.

   - bpo-27774(24): Fix possible Py_DECREF on unowned object in _sre.

   - bpo-27760(25): Fix possible integer overflow in binascii.b2a_qp.

   - bpo-27758(26): Fix possible integer overflow in the _csv module for
     large record lengths.

   - bpo-27568(27): Prevent HTTPoxy attack ( CVE 2016-1000110(28)).
     Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is
     set, which indicates that the script is in CGI mode.

   - bpo-7063(29): Remove dead code from the “array” module’s slice
     handling.  Patch by Chuck.

   - bpo-27656(30): Do not assume sched.h defines any SCHED_* constants.

   - bpo-27130(31): In the “zlib” module, fix handling of large buffers
     (typically 4 GiB) when compressing and decompressing.  Previously,
     inputs were limited to 4 GiB, and compression and decompression
     operations did not properly handle results of 4 GiB.

   - bpo-24773(32): Implemented PEP 495(33) (Local Time Disambiguation).

   - Expose the EPOLLEXCLUSIVE constant (when it is defined) in the
     select module.

   - bpo-27567(34): Expose the EPOLLRDHUP and POLLRDHUP constants in the
     select module.

   - bpo-1621(35): Avoid signed int negation overflow in the “audioop”
     module.

   - bpo-27533(36): Release GIL in nt._isdir

   - bpo-17711(37): Fixed unpickling by the persistent ID with protocol
     0.  Original patch by Alexandre Vassalotti.

   - bpo-27522(38): Avoid an unintentional reference cycle in
     email.feedparser.

   - bpo-27512(39): Fix a segfault when os.fspath() called an
     __fspath__() method that raised an exception.  Patch by Xiang
     Zhang.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26027

   (2) https://peps.python.org/pep-0519/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27524

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27598

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25958

   (6) https://bugs.python.org/issue?@action=redirect&bpo=16764

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27736

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27038

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25628

   (10) https://bugs.python.org/issue?@action=redirect&bpo=12345

   (11) https://peps.python.org/pep-0628/

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26823

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27664

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27181

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27573

   (16) https://bugs.python.org/issue?@action=redirect&bpo=6422

   (17) https://bugs.python.org/issue?@action=redirect&bpo=27773

   (18) https://bugs.python.org/issue?@action=redirect&bpo=26750

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26754

   (20) https://bugs.python.org/issue?@action=redirect&bpo=26800

   (21) https://bugs.python.org/issue?@action=redirect&bpo=26981

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27661

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27783

   (24) https://bugs.python.org/issue?@action=redirect&bpo=27774

   (25) https://bugs.python.org/issue?@action=redirect&bpo=27760

   (26) https://bugs.python.org/issue?@action=redirect&bpo=27758

   (27) https://bugs.python.org/issue?@action=redirect&bpo=27568

   (28) https://www.cve.org/CVERecord?id=CVE-2016-1000110

   (29) https://bugs.python.org/issue?@action=redirect&bpo=7063

   (30) https://bugs.python.org/issue?@action=redirect&bpo=27656

   (31) https://bugs.python.org/issue?@action=redirect&bpo=27130

   (32) https://bugs.python.org/issue?@action=redirect&bpo=24773

   (33) https://peps.python.org/pep-0495/

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27567

   (35) https://bugs.python.org/issue?@action=redirect&bpo=1621

   (36) https://bugs.python.org/issue?@action=redirect&bpo=27533

   (37) https://bugs.python.org/issue?@action=redirect&bpo=17711

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27522

   (39) https://bugs.python.org/issue?@action=redirect&bpo=27512


File: python.info,  Node: IDLE<57>,  Next: Tests<76>,  Prev: Library<162>,  Up: Python 3 6 0 alpha 4

1.23.95.3 IDLE
..............

   - bpo-27714(1): text_textview and test_autocomplete now pass when
     re-run in the same process.  This occurs when test_idle fails when
     run with the -w option but without -jn.  Fix warning from
     test_config.

   - bpo-27621(2): Put query response validation error messages in the
     query box itself instead of in a separate messagebox.  Redo tests
     to match.  Add Mac OSX refinements.  Original patch by Mark
     Roseman.

   - bpo-27620(3): Escape key now closes Query box as cancelled.

   - bpo-27609(4): IDLE: tab after initial whitespace should tab, not
     autocomplete.  This fixes problem with writing docstrings at least
     twice indented.

   - bpo-27609(5): Explicitly return None when there are also non-None
     returns.  In a few cases, reverse a condition and eliminate a
     return.

   - bpo-25507(6): IDLE no longer runs buggy code because of its tkinter
     imports.  Users must include the same imports required to run
     directly in Python.

   - bpo-27173(7): Add ‘IDLE Modern Unix’ to the built-in key sets.
     Make the default key set depend on the platform.  Add tests for the
     changes to the config module.

   - bpo-27452(8): add line counter and crc to IDLE configHandler test
     dump.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27714

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27621

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27620

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27609

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27609

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25507

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27173

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27452


File: python.info,  Node: Tests<76>,  Next: Windows<72>,  Prev: IDLE<57>,  Up: Python 3 6 0 alpha 4

1.23.95.4 Tests
...............

   - bpo-25805(1): Skip a test in test_pkgutil as needed that doesn’t
     work when ‘__name__ == __main__’.  Patch by SilentGhost.

   - bpo-27472(2): Add test.support.unix_shell as the path to the
     default shell.

   - bpo-27369(3): In test_pyexpat, avoid testing an error message
     detail that changed in Expat 2.2.0.

   - bpo-27594(4): Prevent assertion error when running test_ast with
     coverage enabled: ensure code object has a valid first line number.
     Patch suggested by Ivan Levkivskyi.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25805

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27472

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27369

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27594


File: python.info,  Node: Windows<72>,  Next: Build<84>,  Prev: Tests<76>,  Up: Python 3 6 0 alpha 4

1.23.95.5 Windows
.................

   - bpo-27647(1): Update bundled Tcl/Tk to 8.6.6.

   - bpo-27610(2): Adds PEP 514(3) metadata to Windows installer

   - bpo-27469(4): Adds a shell extension to the launcher so that drag
     and drop works correctly.

   - bpo-27309(5): Enables proper Windows styles in python[w].exe
     manifest.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27647

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27610

   (3) https://peps.python.org/pep-0514/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27469

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27309


File: python.info,  Node: Build<84>,  Prev: Windows<72>,  Up: Python 3 6 0 alpha 4

1.23.95.6 Build
...............

   - bpo-27713(1): Suppress spurious build warnings when updating
     importlib’s bootstrap files.  Patch by Xiang Zhang

   - bpo-25825(2): Correct the references to Modules/python.exp, which
     is required on AIX. The references were accidentally changed in
     3.5.0a1.

   - bpo-27453(3): CPP invocation in configure must use CPPFLAGS. Patch
     by Chi Hsuan Yen.

   - bpo-27641(4): The configure script now inserts comments into the
     makefile to prevent the pgen and _freeze_importlib executables from
     being cross-compiled.

   - bpo-26662(5): Set PYTHON_FOR_GEN in configure as the Python program
     to be used for file generation during the build.

   - bpo-10910(6): Avoid C++ compilation errors on FreeBSD and OS X.
     Also update FreedBSD version checks for the original ctype UTF-8
     workaround.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27713

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25825

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27453

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27641

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26662

   (6) https://bugs.python.org/issue?@action=redirect&bpo=10910


File: python.info,  Node: Python 3 6 0 alpha 3,  Next: Python 3 6 0 alpha 2,  Prev: Python 3 6 0 alpha 4,  Up: Changelog

1.23.96 Python 3.6.0 alpha 3
----------------------------

'Release date: 2016-07-11'

* Menu:

* Security: Security<51>.
* Core and Builtins: Core and Builtins<161>.
* Library: Library<163>.
* IDLE: IDLE<58>.
* C API: C API<71>.
* Build: Build<85>.
* Tools/Demos: Tools/Demos<45>.
* Documentation: Documentation<73>.
* Tests: Tests<77>.


File: python.info,  Node: Security<51>,  Next: Core and Builtins<161>,  Up: Python 3 6 0 alpha 3

1.23.96.1 Security
..................

   - bpo-27278(1): Fix os.urandom() implementation using getrandom() on
     Linux.  Truncate size to INT_MAX and loop until we collected enough
     random bytes, instead of casting a directly Py_ssize_t to int.

   - bpo-22636(2): Avoid shell injection problems with
     ctypes.util.find_library().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27278

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22636


File: python.info,  Node: Core and Builtins<161>,  Next: Library<163>,  Prev: Security<51>,  Up: Python 3 6 0 alpha 3

1.23.96.2 Core and Builtins
...........................

   - bpo-27473(1): Fixed possible integer overflow in bytes and
     bytearray concatenations.  Patch by Xiang Zhang.

   - bpo-23034(2): The output of a special Python build with defined
     COUNT_ALLOCS, SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now
     off by default.  It can be re-enabled using the “-X showalloccount”
     option.  It now outputs to stderr instead of stdout.

   - bpo-27443(3): __length_hint__() of bytearray iterators no longer
     return a negative integer for a resized bytearray.

   - bpo-27007(4): The fromhex() class methods of bytes and bytearray
     subclasses now return an instance of corresponding subclass.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27473

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23034

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27443

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27007


File: python.info,  Node: Library<163>,  Next: IDLE<58>,  Prev: Core and Builtins<161>,  Up: Python 3 6 0 alpha 3

1.23.96.3 Library
.................

   - bpo-26844(1): Fix error message for imp.find_module() to refer to
     ‘path’ instead of ‘name’.  Patch by Lev Maximov.

   - bpo-23804(2): Fix SSL zero-length recv() calls to not block and not
     raise an error about unclean EOF.

   - bpo-27466(3): Change time format returned by
     http.cookie.time2netscape, confirming the netscape cookie format
     and making it consistent with documentation.

   - bpo-21708(4): Deprecated dbm.dumb behavior that differs from common
     dbm behavior: creating a database in ‘r’ and ‘w’ modes and
     modifying a database in ‘r’ mode.

   - bpo-26721(5): Change the socketserver.StreamRequestHandler.wfile
     attribute to implement BufferedIOBase.  In particular, the write()
     method no longer does partial writes.

   - bpo-22115(6): Added methods trace_add, trace_remove and trace_info
     in the tkinter.Variable class.  They replace old methods
     trace_variable, trace, trace_vdelete and trace_vinfo that use
     obsolete Tcl commands and might not work in future versions of Tcl.
     Fixed old tracing methods: trace_vdelete() with wrong mode no
     longer break tracing, trace_vinfo() now always returns a list of
     pairs of strings, tracing in the “u” mode now works.

   - bpo-26243(7): Only the level argument to zlib.compress() is keyword
     argument now.  The first argument is positional-only.

   - bpo-27038(8): Expose the DirEntry type as os.DirEntry.  Code patch
     by Jelle Zijlstra.

   - bpo-27186(9): Update os.fspath()/PyOS_FSPath() to check the return
     value of __fspath__() to be either str or bytes.

   - bpo-18726(10): All optional parameters of the dump(), dumps(),
     load() and loads() functions and JSONEncoder and JSONDecoder class
     constructors in the json module are now keyword-only.

   - bpo-27319(11): Methods selection_set(), selection_add(),
     selection_remove() and selection_toggle() of ttk.TreeView now allow
     passing multiple items as multiple arguments instead of passing
     them as a tuple.  Deprecated undocumented ability of calling the
     selection() method with arguments.

   - bpo-27079(12): Fixed curses.ascii functions isblank(), iscntrl()
     and ispunct().

   - bpo-27294(13): Numerical state in the repr for Tkinter event
     objects is now represented as a combination of known flags.

   - bpo-27177(14): Match objects in the re module now support
     index-like objects as group indices.  Based on patches by Jeroen
     Demeyer and Xiang Zhang.

   - bpo-26754(15): Some functions (compile() etc) accepted a filename
     argument encoded as an iterable of integers.  Now only strings and
     byte-like objects are accepted.

   - bpo-26536(16): socket.ioctl now supports SIO_LOOPBACK_FAST_PATH.
     Patch by Daniel Stokes.

   - bpo-27048(17): Prevents distutils failing on Windows when
     environment variables contain non-ASCII characters

   - bpo-27330(18): Fixed possible leaks in the ctypes module.

   - bpo-27238(19): Got rid of bare excepts in the turtle module.
     Original patch by Jelle Zijlstra.

   - bpo-27122(20): When an exception is raised within the context being
     managed by a contextlib.ExitStack() and one of the exit stack
     generators catches and raises it in a chain, do not re-raise the
     original exception when exiting, let the new chained one through.
     This avoids the PEP 479(21) bug described in issue25782.

   - bpo-16864(22): sqlite3.Cursor.lastrowid now supports REPLACE
     statement.  Initial patch by Alex LordThorsen.

   - bpo-26386(23): Fixed ttk.TreeView selection operations with item
     id’s containing spaces.

   - bpo-8637(24): Honor a pager set by the env var MANPAGER (in
     preference to one set by the env var PAGER).

   - bpo-16182(25): Fix various functions in the “readline” module to
     use the locale encoding, and fix get_begidx() and get_endidx() to
     return code point indexes.

   - bpo-27392(26): Add loop.connect_accepted_socket().  Patch by Jim
     Fulton.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26844

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23804

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27466

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21708

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26721

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22115

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26243

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27038

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (10) https://bugs.python.org/issue?@action=redirect&bpo=18726

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27319

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27079

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27294

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27177

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26754

   (16) https://bugs.python.org/issue?@action=redirect&bpo=26536

   (17) https://bugs.python.org/issue?@action=redirect&bpo=27048

   (18) https://bugs.python.org/issue?@action=redirect&bpo=27330

   (19) https://bugs.python.org/issue?@action=redirect&bpo=27238

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27122

   (21) https://peps.python.org/pep-0479/

   (22) https://bugs.python.org/issue?@action=redirect&bpo=16864

   (23) https://bugs.python.org/issue?@action=redirect&bpo=26386

   (24) https://bugs.python.org/issue?@action=redirect&bpo=8637

   (25) https://bugs.python.org/issue?@action=redirect&bpo=16182

   (26) https://bugs.python.org/issue?@action=redirect&bpo=27392


File: python.info,  Node: IDLE<58>,  Next: C API<71>,  Prev: Library<163>,  Up: Python 3 6 0 alpha 3

1.23.96.4 IDLE
..............

   - bpo-27477(1): IDLE search dialogs now use ttk widgets.

   - bpo-27173(2): Add ‘IDLE Modern Unix’ to the built-in key sets.
     Make the default key set depend on the platform.  Add tests for the
     changes to the config module.

   - bpo-27452(3): make command line “idle-test> python test_help.py”
     work.  __file__ is relative when python is started in the file’s
     directory.

   - bpo-27452(4): add line counter and crc to IDLE configHandler test
     dump.

   - bpo-27380(5): IDLE: add query.py with base Query dialog and ttk
     widgets.  Module had subclasses SectionName, ModuleName, and
     HelpSource, which are used to get information from users by
     configdialog and file =>Load Module.  Each subclass has itw own
     validity checks.  Using ModuleName allows users to edit bad module
     names instead of starting over.  Add tests and delete the two files
     combined into the new one.

   - bpo-27372(6): Test_idle no longer changes the locale.

   - bpo-27365(7): Allow non-ascii chars in IDLE NEWS.txt, for
     contributor names.

   - bpo-27245(8): IDLE: Cleanly delete custom themes and key bindings.
     Previously, when IDLE was started from a console or by import, a
     cascade of warnings was emitted.  Patch by Serhiy Storchaka.

   - bpo-24137(9): Run IDLE, test_idle, and htest with tkinter default
     root disabled.  Fix code and tests that fail with this restriction.
     Fix htests to not create a second and redundant root and mainloop.

   - bpo-27310(10): Fix IDLE.app failure to launch on OS X due to
     vestigial import.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27477

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27173

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27452

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27452

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27380

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27372

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27365

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27245

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24137

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27310


File: python.info,  Node: C API<71>,  Next: Build<85>,  Prev: IDLE<58>,  Up: Python 3 6 0 alpha 3

1.23.96.5 C API
...............

   - bpo-26754(1): PyUnicode_FSDecoder() accepted a filename argument
     encoded as an iterable of integers.  Now only strings and byte-like
     objects are accepted.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26754


File: python.info,  Node: Build<85>,  Next: Tools/Demos<45>,  Prev: C API<71>,  Up: Python 3 6 0 alpha 3

1.23.96.6 Build
...............

   - bpo-28066(1): Fix the logic that searches build directories for
     generated include files when building outside the source tree.

   - bpo-27442(2): Expose the Android API level that python was built
     against, in sysconfig.get_config_vars() as ‘ANDROID_API_LEVEL’.

   - bpo-27434(3): The interpreter that runs the cross-build, found in
     PATH, must now be of the same feature version (e.g.  3.6) as the
     source being built.

   - bpo-26930(4): Update Windows builds to use OpenSSL 1.0.2h.

   - bpo-23968(5): Rename the platform directory from plat-$(MACHDEP) to
     plat-$(PLATFORM_TRIPLET). Rename the config directory (LIBPL) from
     config-$(LDVERSION) to config-$(LDVERSION)-$(PLATFORM_TRIPLET).
     Install the platform specific _sysconfigdata module into the
     platform directory and rename it to include the ABIFLAGS.

   - Don’t use largefile support for GNU/Hurd.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28066

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27442

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27434

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26930

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23968


File: python.info,  Node: Tools/Demos<45>,  Next: Documentation<73>,  Prev: Build<85>,  Up: Python 3 6 0 alpha 3

1.23.96.7 Tools/Demos
.....................

   - bpo-27332(1): Fixed the type of the first argument of module-level
     functions generated by Argument Clinic.  Patch by Petr Viktorin.

   - bpo-27418(2): Fixed Tools/importbench/importbench.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27332

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27418


File: python.info,  Node: Documentation<73>,  Next: Tests<77>,  Prev: Tools/Demos<45>,  Up: Python 3 6 0 alpha 3

1.23.96.8 Documentation
.......................

   - bpo-19489(1): Moved the search box from the sidebar to the header
     and footer of each page.  Patch by Ammar Askar.

   - bpo-27285(2): Update documentation to reflect the deprecation of
     ‘pyvenv’ and normalize on the term “virtual environment”.  Patch by
     Steve Piercy.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19489

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27285


File: python.info,  Node: Tests<77>,  Prev: Documentation<73>,  Up: Python 3 6 0 alpha 3

1.23.96.9 Tests
...............

   - bpo-27027(1): Added test.support.is_android that is True when this
     is an Android build.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27027


File: python.info,  Node: Python 3 6 0 alpha 2,  Next: Python 3 6 0 alpha 1,  Prev: Python 3 6 0 alpha 3,  Up: Changelog

1.23.97 Python 3.6.0 alpha 2
----------------------------

'Release date: 2016-06-13'

* Menu:

* Security: Security<52>.
* Core and Builtins: Core and Builtins<162>.
* Library: Library<164>.
* IDLE: IDLE<59>.
* Documentation: Documentation<74>.
* Tests: Tests<78>.
* Windows: Windows<73>.
* Build: Build<86>.
* C API: C API<72>.
* Tools/Demos: Tools/Demos<46>.


File: python.info,  Node: Security<52>,  Next: Core and Builtins<162>,  Up: Python 3 6 0 alpha 2

1.23.97.1 Security
..................

   - bpo-26556(1): Update expat to 2.1.1, fixes CVE 2015-1283(2).

   - Fix TLS stripping vulnerability in smtplib, CVE 2016-0772(3).
     Reported by Team Oststrom.

   - bpo-26839(4): On Linux, *note os.urandom(): 526. now calls
     ‘getrandom()’ with ‘GRND_NONBLOCK’ to fall back on reading
     ‘/dev/urandom’ if the urandom entropy pool is not initialized yet.
     Patch written by Colm Buckley.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26556

   (2) https://www.cve.org/CVERecord?id=CVE-2015-1283

   (3) https://www.cve.org/CVERecord?id=CVE-2016-0772

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26839


File: python.info,  Node: Core and Builtins<162>,  Next: Library<164>,  Prev: Security<52>,  Up: Python 3 6 0 alpha 2

1.23.97.2 Core and Builtins
...........................

   - bpo-27095(1): Simplified MAKE_FUNCTION and removed MAKE_CLOSURE
     opcodes.  Patch by Demur Rumed.

   - bpo-27190(2): Raise NotSupportedError if sqlite3 is older than
     3.3.1.  Patch by Dave Sawyer.

   - bpo-27286(3): Fixed compiling BUILD_MAP_UNPACK_WITH_CALL opcode.
     Calling function with generalized unpacking (PEP 448) and
     conflicting keyword names could cause undefined behavior.

   - bpo-27140(4): Added BUILD_CONST_KEY_MAP opcode.

   - bpo-27186(5): Add support for os.PathLike objects to open() (part
     of PEP 519(6)).

   - bpo-27066(7): Fixed SystemError if a custom opener (for open())
     returns a negative number without setting an exception.

   - bpo-26983(8): float() now always return an instance of exact float.
     The deprecation warning is emitted if __float__ returns an instance
     of a strict subclass of float.  In a future versions of Python this
     can be an error.

   - bpo-27097(9): Python interpreter is now about 7% faster due to
     optimized instruction decoding.  Based on patch by Demur Rumed.

   - bpo-26647(10): Python interpreter now uses 16-bit wordcode instead
     of bytecode.  Patch by Demur Rumed.

   - bpo-23275(11): Allow assigning to an empty target list in round
     brackets: () = iterable.

   - bpo-27243(12): Update the __aiter__ protocol: instead of returning
     an awaitable that resolves to an asynchronous iterator, the
     asynchronous iterator should be returned directly.  Doing the
     former will trigger a PendingDeprecationWarning.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27095

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27190

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27286

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27140

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (6) https://peps.python.org/pep-0519/

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27066

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26983

   (9) https://bugs.python.org/issue?@action=redirect&bpo=27097

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26647

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23275

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27243


File: python.info,  Node: Library<164>,  Next: IDLE<59>,  Prev: Core and Builtins<162>,  Up: Python 3 6 0 alpha 2

1.23.97.3 Library
.................

   - Comment out socket (SO_REUSEPORT) and posix (O_SHLOCK, O_EXLOCK)
     constants exposed on the API which are not implemented on GNU/Hurd.
     They would not work at runtime anyway.

   - bpo-27025(1): Generated names for Tkinter widgets are now more
     meaningful and recognizable.

   - bpo-25455(2): Fixed crashes in repr of recursive
     ElementTree.Element and functools.partial objects.

   - bpo-27294(3): Improved repr for Tkinter event objects.

   - bpo-20508(4): Improve exception message of
     IPv{4,6}Network.__getitem__.  Patch by Gareth Rees.

   - bpo-21386(5): Implement missing IPv4Address.is_global property.  It
     was documented since 07a5610bae9d.  Initial patch by Roger Luethi.

   - bpo-27029(6): Removed deprecated support of universal newlines mode
     from ZipFile.open().

   - bpo-27030(7): Unknown escapes consisting of ‘'\'’ and an ASCII
     letter in regular expressions now are errors.  The re.LOCALE flag
     now can be used only with bytes patterns.

   - bpo-27186(8): Add os.PathLike support to DirEntry (part of PEP
     519(9)).  Initial patch by Jelle Zijlstra.

   - bpo-20900(10): distutils register command now decodes HTTP
     responses correctly.  Initial patch by ingrid.

   - bpo-27186(11): Add os.PathLike support to pathlib, removing its
     provisional status (part of PEP 519).  Initial patch by Dusty
     Phillips.

   - bpo-27186(12): Add support for os.PathLike objects to os.fsencode()
     and os.fsdecode() (part of PEP 519(13)).

   - bpo-27186(14): Introduce os.PathLike and os.fspath() (part of PEP
     519(15)).

   - A new version of typing.py provides several new classes and
     features: @overload outside stubs, Reversible, DefaultDict, Text,
     ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug
     fixes (note that some of the new features are not yet implemented
     in mypy or other static analyzers).  Also classes for PEP 492(16)
     (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact
     they made it into 3.5.1 but were never mentioned).

   - bpo-25738(17): Stop http.server.BaseHTTPRequestHandler.send_error()
     from sending a message body for 205 Reset Content.  Also, don’t
     send Content header fields in responses that don’t have a body.
     Patch by Susumu Koshiba.

   - bpo-21313(18): Fix the “platform” module to tolerate when
     sys.version contains truncated build information.

   - bpo-23883(19): Added missing APIs to __all__ to match the
     documented APIs for the following modules: cgi, mailbox, mimetypes,
     plistlib and smtpd.  Patches by Jacek Kołodziej.

   - bpo-27164(20): In the zlib module, allow decompressing raw Deflate
     streams with a predefined zdict.  Based on patch by Xiang Zhang.

   - bpo-24291(21): Fix wsgiref.simple_server.WSGIRequestHandler to
     completely write data to the client.  Previously it could do
     partial writes and truncate data.  Also,
     wsgiref.handler.ServerHandler can now handle stdout doing partial
     writes, but this is deprecated.

   - bpo-21272(22): Use _sysconfigdata.py to initialize
     distutils.sysconfig.

   - bpo-19611(23): *note inspect: 7e. now reports the implicit ‘.0’
     parameters generated by the compiler for comprehension and
     generator expression scopes as if they were positional-only
     parameters called ‘implicit0’.  Patch by Jelle Zijlstra.

   - bpo-26809(24): Add ‘__all__’ to *note string: d3.  Patch by Emanuel
     Barry.

   - bpo-26373(25): subprocess.Popen.communicate now correctly ignores
     BrokenPipeError when the child process dies before .communicate()
     is called in more/all circumstances.

   - signal, socket, and ssl module IntEnum constant name lookups now
     return a consistent name for values having multiple names.  Ex:
     signal.Signals(6) now refers to itself as signal.SIGALRM rather
     than flipping between that and signal.SIGIOT based on the
     interpreter’s hash randomization seed.

   - bpo-27167(26): Clarify the subprocess.CalledProcessError error
     message text when the child process died due to a signal.

   - bpo-25931(27): Don’t define socketserver.Forking* names on
     platforms such as Windows that do not support os.fork().

   - bpo-21776(28): distutils.upload now correctly handles HTTPError.
     Initial patch by Claudiu Popa.

   - bpo-26526(29): Replace custom parse tree validation in the parser
     module with a simple DFA validator.

   - bpo-27114(30): Fix SSLContext._load_windows_store_certs fails with
     PermissionError

   - bpo-18383(31): Avoid creating duplicate filters when using
     filterwarnings and simplefilter.  Based on patch by Alex Shkop.

   - bpo-23026(32): winreg.QueryValueEx() now return an integer for
     REG_QWORD type.

   - bpo-26741(33): subprocess.Popen destructor now emits a
     ResourceWarning warning if the child process is still running.

   - bpo-27056(34): Optimize pickle.load() and pickle.loads(), up to 10%
     faster to deserialize a lot of small objects.

   - bpo-21271(35): New keyword only parameters in reset_mock call.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27025

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25455

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27294

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20508

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21386

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27029

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27030

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (9) https://peps.python.org/pep-0519/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=20900

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (13) https://peps.python.org/pep-0519/

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (15) https://peps.python.org/pep-0519/

   (16) https://peps.python.org/pep-0492/

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25738

   (18) https://bugs.python.org/issue?@action=redirect&bpo=21313

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23883

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27164

   (21) https://bugs.python.org/issue?@action=redirect&bpo=24291

   (22) https://bugs.python.org/issue?@action=redirect&bpo=21272

   (23) https://bugs.python.org/issue?@action=redirect&bpo=19611

   (24) https://bugs.python.org/issue?@action=redirect&bpo=26809

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26373

   (26) https://bugs.python.org/issue?@action=redirect&bpo=27167

   (27) https://bugs.python.org/issue?@action=redirect&bpo=25931

   (28) https://bugs.python.org/issue?@action=redirect&bpo=21776

   (29) https://bugs.python.org/issue?@action=redirect&bpo=26526

   (30) https://bugs.python.org/issue?@action=redirect&bpo=27114

   (31) https://bugs.python.org/issue?@action=redirect&bpo=18383

   (32) https://bugs.python.org/issue?@action=redirect&bpo=23026

   (33) https://bugs.python.org/issue?@action=redirect&bpo=26741

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27056

   (35) https://bugs.python.org/issue?@action=redirect&bpo=21271


File: python.info,  Node: IDLE<59>,  Next: Documentation<74>,  Prev: Library<164>,  Up: Python 3 6 0 alpha 2

1.23.97.4 IDLE
..............

   - bpo-5124(1): Paste with text selected now replaces the selection on
     X11.  This matches how paste works on Windows, Mac, most modern
     Linux apps, and ttk widgets.  Original patch by Serhiy Storchaka.

   - bpo-24750(2): Switch all scrollbars in IDLE to ttk versions.  Where
     needed, minimal tests are added to cover changes.

   - bpo-24759(3): IDLE requires tk 8.5 and availability ttk widgets.
     Delete now unneeded tk version tests and code for older versions.
     Add test for IDLE syntax colorizer.

   - bpo-27239(4): idlelib.macosx.isXyzTk functions initialize as
     needed.

   - bpo-27262(5): move Aqua unbinding code, which enable context menus,
     to macosx.

   - bpo-24759(6): Make clear in idlelib.idle_test.__init__ that the
     directory is a private implementation of test.test_idle and tool
     for maintainers.

   - bpo-27196(7): Stop ‘ThemeChanged’ warnings when running IDLE tests.
     These persisted after other warnings were suppressed in #20567.
     Apply Serhiy Storchaka’s update_idletasks solution to four test
     files.  Record this additional advice in idle_test/README.txt

   - bpo-20567(8): Revise idle_test/README.txt with advice about
     avoiding tk warning messages from tests.  Apply advice to several
     IDLE tests.

   - bpo-24225(9): Update idlelib/README.txt with new file names and
     event handlers.

   - bpo-27156(10): Remove obsolete code not used by IDLE.

   - bpo-27117(11): Make colorizer htest and turtledemo work with dark
     themes.  Move code for configuring text widget colors to a new
     function.

   - bpo-24225(12): Rename many ‘idlelib/*.py’ and ‘idle_test/test_*.py’
     files.  Edit files to replace old names with new names when the old
     name referred to the module rather than the class it contained.
     See the issue and IDLE section in What’s New in 3.6 for more.

   - bpo-26673(13): When tk reports font size as 0, change to size 10.
     Such fonts on Linux prevented the configuration dialog from
     opening.

   - bpo-21939(14): Add test for IDLE’s percolator.  Original patch by
     Saimadhav Heblikar.

   - bpo-21676(15): Add test for IDLE’s replace dialog.  Original patch
     by Saimadhav Heblikar.

   - bpo-18410(16): Add test for IDLE’s search dialog.  Original patch
     by Westley Martínez.

   - bpo-21703(17): Add test for undo delegator.  Patch mostly by
     Saimadhav Heblikar .

   - bpo-27044(18): Add ConfigDialog.remove_var_callbacks to stop memory
     leaks.

   - bpo-23977(19): Add more asserts to test_delegator.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5124

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24750

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24759

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27239

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27262

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24759

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27196

   (8) https://bugs.python.org/issue?@action=redirect&bpo=20567

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24225

   (10) https://bugs.python.org/issue?@action=redirect&bpo=27156

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27117

   (12) https://bugs.python.org/issue?@action=redirect&bpo=24225

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26673

   (14) https://bugs.python.org/issue?@action=redirect&bpo=21939

   (15) https://bugs.python.org/issue?@action=redirect&bpo=21676

   (16) https://bugs.python.org/issue?@action=redirect&bpo=18410

   (17) https://bugs.python.org/issue?@action=redirect&bpo=21703

   (18) https://bugs.python.org/issue?@action=redirect&bpo=27044

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23977


File: python.info,  Node: Documentation<74>,  Next: Tests<78>,  Prev: IDLE<59>,  Up: Python 3 6 0 alpha 2

1.23.97.5 Documentation
.......................

   - bpo-16484(1): Change the default PYTHONDOCS URL to “https:”, and
     fix the resulting links to use lowercase.  Patch by Sean Rodman,
     test by Kaushik Nadikuditi.

   - bpo-24136(2): Document the new PEP 448(3) unpacking syntax of 3.5.

   - bpo-22558(4): Add remaining doc links to source code for
     Python-coded modules.  Patch by Yoni Lavi.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=16484

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24136

   (3) https://peps.python.org/pep-0448/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22558


File: python.info,  Node: Tests<78>,  Next: Windows<73>,  Prev: Documentation<74>,  Up: Python 3 6 0 alpha 2

1.23.97.6 Tests
...............

   - bpo-25285(1): regrtest now uses subprocesses when the -j1 command
     line option is used: each test file runs in a fresh child process.
     Before, the -j1 option was ignored.

   - bpo-25285(2): Tools/buildbot/test.bat script now uses -j1 by
     default to run each test file in fresh child process.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25285

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25285


File: python.info,  Node: Windows<73>,  Next: Build<86>,  Prev: Tests<78>,  Up: Python 3 6 0 alpha 2

1.23.97.7 Windows
.................

   - bpo-27064(1): The py.exe launcher now defaults to Python 3.  The
     Windows launcher ‘py.exe’ no longer prefers an installed Python 2
     version over Python 3 by default when used interactively.

   - bpo-17500(2): Remove unused and outdated icons.  (See also:
     ‘https://github.com/python/pythondotorg/issues/945’)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27064

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17500


File: python.info,  Node: Build<86>,  Next: C API<72>,  Prev: Windows<73>,  Up: Python 3 6 0 alpha 2

1.23.97.8 Build
...............

   - bpo-27229(1): Fix the cross-compiling pgen rule for in-tree builds.
     Patch by Xavier de Gaye.

   - bpo-26930(2): Update OS X 10.5+ 32-bit-only installer to build and
     link with OpenSSL 1.0.2h.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27229

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26930


File: python.info,  Node: C API<72>,  Next: Tools/Demos<46>,  Prev: Build<86>,  Up: Python 3 6 0 alpha 2

1.23.97.9 C API
...............

   - bpo-27186(1): Add the PyOS_FSPath() function (part of PEP 519(2)).

   - bpo-26282(3): PyArg_ParseTupleAndKeywords() now supports
     positional-only parameters.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27186

   (2) https://peps.python.org/pep-0519/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26282


File: python.info,  Node: Tools/Demos<46>,  Prev: C API<72>,  Up: Python 3 6 0 alpha 2

1.23.97.10 Tools/Demos
......................

   - bpo-26282(1): Argument Clinic now supports positional-only and
     keyword parameters in the same function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26282


File: python.info,  Node: Python 3 6 0 alpha 1,  Next: Python 3 5 5 final,  Prev: Python 3 6 0 alpha 2,  Up: Changelog

1.23.98 Python 3.6.0 alpha 1
----------------------------

'Release date: 2016-05-16'

* Menu:

* Security: Security<53>.
* Core and Builtins: Core and Builtins<163>.
* Library: Library<165>.
* IDLE: IDLE<60>.
* Documentation: Documentation<75>.
* Tests: Tests<79>.
* Build: Build<87>.
* Windows: Windows<74>.
* Tools/Demos: Tools/Demos<47>.
* C API: C API<73>.


File: python.info,  Node: Security<53>,  Next: Core and Builtins<163>,  Up: Python 3 6 0 alpha 1

1.23.98.1 Security
..................

   - bpo-26657(1): Fix directory traversal vulnerability with
     http.server on Windows.  This fixes a regression that was
     introduced in 3.3.4rc1 and 3.4.0rc1.  Based on patch by Philipp
     Hagemeister.

   - bpo-26313(2): ssl.py _load_windows_store_certs fails if windows
     cert store is empty.  Patch by Baji.

   - bpo-25939(3): On Windows open the cert store readonly in
     ssl.enum_certificates.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26657

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26313

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25939


File: python.info,  Node: Core and Builtins<163>,  Next: Library<165>,  Prev: Security<53>,  Up: Python 3 6 0 alpha 1

1.23.98.2 Core and Builtins
...........................

   - bpo-20041(1): Fixed TypeError when frame.f_trace is set to None.
     Patch by Xavier de Gaye.

   - bpo-26168(2): Fixed possible refleaks in failing Py_BuildValue()
     with the “N” format unit.

   - bpo-26991(3): Fix possible refleak when creating a function with
     annotations.

   - bpo-27039(4): Fixed bytearray.remove() for values greater than 127.
     Based on patch by Joe Jevnik.

   - bpo-23640(5): int.from_bytes() no longer bypasses constructors for
     subclasses.

   - bpo-27005(6): Optimized the float.fromhex() class method for exact
     float.  It is now 2 times faster.

   - bpo-18531(7): Single var-keyword argument of dict subtype was
     passed unscathed to the C-defined function.  Now it is converted to
     exact dict.

   - bpo-26811(8): gc.get_objects() no longer contains a broken tuple
     with NULL pointer.

   - bpo-20120(9): Use RawConfigParser for .pypirc parsing, removing
     support for interpolation unintentionally added with move to Python
     3.  Behavior no longer does any interpolation in .pypirc files,
     matching behavior in Python 2.7 and Setuptools 19.0.

   - bpo-26249(10): Memory functions of the *note PyMem_Malloc(): c87.
     domain (*note PYMEM_DOMAIN_MEM: c8a.) now use the *note pymalloc
     allocator: d37. rather than system ‘malloc()’.  Applications
     calling ‘PyMem_Malloc()’ without holding the GIL can now crash: use
     ‘PYTHONMALLOC=debug’ environment variable to validate the usage of
     memory allocators in your application.

   - bpo-26802(11): Optimize function calls only using unpacking like
     ‘func(*tuple)’ (no other positional argument, no keyword): avoid
     copying the tuple.  Patch written by Joe Jevnik.

   - bpo-26659(12): Make the builtin slice type support cycle
     collection.

   - bpo-26718(13): super.__init__ no longer leaks memory if called
     multiple times.  NOTE: A direct call of super.__init__ is not
     endorsed!

   - bpo-27138(14): Fix the doc comment for FileFinder.find_spec().

   - bpo-27147(15): Mention PEP 420(16) in the importlib docs.

   - bpo-25339(17): PYTHONIOENCODING now has priority over locale in
     setting the error handler for stdin and stdout.

   - bpo-26494(18): Fixed crash on iterating exhausting iterators.
     Affected classes are generic sequence iterators, iterators of str,
     bytes, bytearray, list, tuple, set, frozenset, dict, OrderedDict,
     corresponding views and os.scandir() iterator.

   - bpo-26574(19): Optimize ‘bytes.replace(b'', b'.')’ and
     ‘bytearray.replace(b'', b'.')’.  Patch written by Josh Snider.

   - bpo-26581(20): If coding cookie is specified multiple times on a
     line in Python source code file, only the first one is taken to
     account.

   - bpo-19711(21): Add tests for reloading namespace packages.

   - bpo-21099(22): Switch applicable importlib tests to use PEP 451(23)
     API.

   - bpo-26563(24): Debug hooks on Python memory allocators now raise a
     fatal error if functions of the *note PyMem_Malloc(): c87. family
     are called without holding the GIL.

   - bpo-26564(25): On error, the debug hooks on Python memory
     allocators now use the *note tracemalloc: ff. module to get the
     traceback where a memory block was allocated.

   - bpo-26558(26): The debug hooks on Python memory allocator *note
     PyObject_Malloc(): c89. now detect when functions are called
     without holding the GIL.

   - bpo-26516(27): Add *note PYTHONMALLOC: c85. environment variable to
     set the Python memory allocators and/or install debug hooks.

   - bpo-26516(28): The *note PyMem_SetupDebugHooks(): c8b. function can
     now also be used on Python compiled in release mode.

   - bpo-26516(29): The *note PYTHONMALLOCSTATS: 1ce8. environment
     variable can now also be used on Python compiled in release mode.
     It now has no effect if set to an empty string.

   - bpo-26516(30): In debug mode, debug hooks are now also installed on
     Python memory allocators when Python is configured without
     pymalloc.

   - bpo-26464(31): Fix str.translate() when string is ASCII and first
     replacements removes character, but next replacement uses a
     non-ASCII character or a string longer than 1 character.
     Regression introduced in Python 3.5.0.

   - bpo-22836(32): Ensure exception reports from PyErr_Display() and
     PyErr_WriteUnraisable() are sensible even when formatting them
     produces secondary errors.  This affects the reports produced by
     sys.__excepthook__() and when __del__() raises an exception.

   - bpo-26302(33): Correct behavior to reject comma as a legal
     character for cookie names.

   - bpo-26136(34): Upgrade the warning when a generator raises
     StopIteration from PendingDeprecationWarning to DeprecationWarning.
     Patch by Anish Shah.

   - bpo-26204(35): The compiler now ignores all constant statements:
     bytes, str, int, float, complex, name constants (None, False,
     True), Ellipsis and ast.Constant; not only str and int.  For
     example, ‘1.0’ is now ignored in ‘def f(): 1.0’.

   - bpo-4806(36): Avoid masking the original TypeError exception when
     using star (‘*’) unpacking in function calls.  Based on patch by
     Hagen Fürstenau and Daniel Urban.

   - bpo-26146(37): Add a new kind of AST node: ‘ast.Constant’.  It can
     be used by external AST optimizers, but the compiler does not emit
     directly such node.

   - bpo-23601(38): Sped-up allocation of dict key objects by using
     Python’s small object allocator.  (Contributed by Julian Taylor.)

   - bpo-18018(39): Import raises ImportError instead of SystemError if
     a relative import is attempted without a known parent package.

   - bpo-25843(40): When compiling code, don’t merge constants if they
     are equal but have a different types.  For example, ‘f1, f2 =
     lambda: 1, lambda: 1.0’ is now correctly compiled to two different
     functions: ‘f1()’ returns ‘1’ (‘int’) and ‘f2()’ returns ‘1.0’
     (‘float’), even if ‘1’ and ‘1.0’ are equal.

   - bpo-26107(41): The format of the ‘co_lnotab’ attribute of code
     objects changes to support negative line number delta.

   - bpo-26154(42): Add a new private _PyThreadState_UncheckedGet()
     function to get the current Python thread state, but don’t issue a
     fatal error if it is NULL. This new function must be used instead
     of accessing directly the _PyThreadState_Current variable.  The
     variable is no more exposed since Python 3.5.1 to hide the exact
     implementation of atomic C types, to avoid compiler issues.

   - bpo-25791(43): If __package__ != __spec__.parent or if neither
     __package__ or __spec__ are defined then ImportWarning is raised.

   - bpo-22995(44): [UPDATE] Comment out the one of the pickleability
     tests in _PyObject_GetState() due to regressions observed in
     Cython-based projects.

   - bpo-25961(45): Disallowed null characters in the type name.

   - bpo-25973(46): Fix segfault when an invalid nonlocal statement
     binds a name starting with two underscores.

   - bpo-22995(47): Instances of extension types with a state that
     aren’t subclasses of list or dict and haven’t implemented any
     pickle-related methods (__reduce__, __reduce_ex__, __getnewargs__,
     __getnewargs_ex__, or __getstate__), can no longer be pickled.
     Including memoryview.

   - bpo-20440(48): Massive replacing unsafe attribute setting code with
     special macro Py_SETREF.

   - bpo-25766(49): Special method __bytes__() now works in str
     subclasses.

   - bpo-25421(50): __sizeof__ methods of builtin types now use dynamic
     basic size.  This allows sys.getsize() to work correctly with their
     subclasses with __slots__ defined.

   - bpo-25709(51): Fixed problem with in-place string concatenation and
     utf-8 cache.

   - bpo-5319(52): New Py_FinalizeEx() API allowing Python to set an
     exit status of 120 on failure to flush buffered streams.

   - bpo-25485(53): telnetlib.Telnet is now a context manager.

   - bpo-24097(54): Fixed crash in object.__reduce__() if slot name is
     freed inside __getattr__.

   - bpo-24731(55): Fixed crash on converting objects with special
     methods __bytes__, __trunc__, and __float__ returning instances of
     subclasses of bytes, int, and float to subclasses of bytes, int,
     and float correspondingly.

   - bpo-25630(56): Fix a possible segfault during argument parsing in
     functions that accept filesystem paths.

   - bpo-23564(57): Fixed a partially broken sanity check in the
     _posixsubprocess internals regarding how fds_to_pass were passed to
     the child.  The bug had no actual impact as subprocess.py already
     avoided it.

   - bpo-25388(58): Fixed tokenizer crash when processing undecodable
     source code with a null byte.

   - bpo-25462(59): The hash of the key now is calculated only once in
     most operations in C implementation of OrderedDict.

   - bpo-22995(60): Default implementation of __reduce__ and
     __reduce_ex__ now rejects builtin types with not defined __new__.

   - bpo-24802(61): Avoid buffer overreads when int(), float(),
     compile(), exec() and eval() are passed bytes-like objects.  These
     objects are not necessarily terminated by a null byte, but the
     functions assumed they were.

   - bpo-25555(62): Fix parser and AST: fill lineno and col_offset of
     “arg” node when compiling AST from Python objects.

   - bpo-24726(63): Fixed a crash and leaking NULL in repr() of
     OrderedDict that was mutated by direct calls of dict methods.

   - bpo-25449(64): Iterating OrderedDict with keys with unstable hash
     now raises KeyError in C implementations as well as in Python
     implementation.

   - bpo-25395(65): Fixed crash when highly nested OrderedDict
     structures were garbage collected.

   - bpo-25401(66): Optimize bytes.fromhex() and bytearray.fromhex():
     they are now between 2x and 3.5x faster.

   - bpo-25399(67): Optimize bytearray % args using the new private
     _PyBytesWriter API. Formatting is now between 2.5 and 5 times
     faster.

   - bpo-25274(68): sys.setrecursionlimit() now raises a RecursionError
     if the new recursion limit is too low depending at the current
     recursion depth.  Modify also the “lower-water mark” formula to
     make it monotonic.  This mark is used to decide when the overflowed
     flag of the thread state is reset.

   - bpo-24402(69): Fix input() to prompt to the redirected stdout when
     sys.stdout.fileno() fails.

   - bpo-25349(70): Optimize bytes % args using the new private
     _PyBytesWriter API. Formatting is now up to 2 times faster.

   - bpo-24806(71): Prevent builtin types that are not allowed to be
     subclassed from being subclassed through multiple inheritance.

   - bpo-25301(72): The UTF-8 decoder is now up to 15 times as fast for
     error handlers: ‘ignore’, ‘replace’ and ‘surrogateescape’.

   - bpo-24848(73): Fixed a number of bugs in UTF-7 decoding of
     misformed data.

   - bpo-25267(74): The UTF-8 encoder is now up to 75 times as fast for
     error handlers: ‘ignore’, ‘replace’, ‘surrogateescape’,
     ‘surrogatepass’.  Patch co-written with Serhiy Storchaka.

   - bpo-25280(75): Import trace messages emitted in verbose (-v) mode
     are no longer formatted twice.

   - bpo-25227(76): Optimize ASCII and latin1 encoders with the
     ‘surrogateescape’ error handler: the encoders are now up to 3 times
     as fast.  Initial patch written by Serhiy Storchaka.

   - bpo-25003(77): On Solaris 11.3 or newer, os.urandom() now uses the
     getrandom() function instead of the getentropy() function.  The
     getentropy() function is blocking to generate very good quality
     entropy, os.urandom() doesn’t need such high-quality entropy.

   - bpo-9232(78): Modify Python’s grammar to allow trailing commas in
     the argument list of a function declaration.  For example, “def
     f(*, a = 3,): pass” is now legal.  Patch from Mark Dickinson.

   - bpo-24965(79): Implement PEP 498(80) “Literal String
     Interpolation”.  This allows you to embed expressions inside
     f-strings, which are converted to normal strings at run time.
     Given x=3, then f’value={x}’ == ‘value=3’.  Patch by Eric V. Smith.

   - bpo-26478(81): Fix semantic bugs when using binary operators with
     dictionary views and tuples.

   - bpo-26171(82): Fix possible integer overflow and heap corruption in
     zipimporter.get_data().

   - bpo-25660(83): Fix TAB key behaviour in REPL with readline.

   - bpo-26288(84): Optimize PyLong_AsDouble.

   - bpo-26289(85): Optimize floor and modulo division for single-digit
     longs.  Microbenchmarks show 2-2.5x improvement.  Built-in ‘divmod’
     function is now also ~10% faster.  (See also: bpo-26315(86))

   - bpo-25887(87): Raise a RuntimeError when a coroutine object is
     awaited more than once.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20041

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26168

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26991

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27039

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23640

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27005

   (7) https://bugs.python.org/issue?@action=redirect&bpo=18531

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26811

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20120

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26249

   (11) https://bugs.python.org/issue?@action=redirect&bpo=26802

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26659

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26718

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27138

   (15) https://bugs.python.org/issue?@action=redirect&bpo=27147

   (16) https://peps.python.org/pep-0420/

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25339

   (18) https://bugs.python.org/issue?@action=redirect&bpo=26494

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26574

   (20) https://bugs.python.org/issue?@action=redirect&bpo=26581

   (21) https://bugs.python.org/issue?@action=redirect&bpo=19711

   (22) https://bugs.python.org/issue?@action=redirect&bpo=21099

   (23) https://peps.python.org/pep-0451/

   (24) https://bugs.python.org/issue?@action=redirect&bpo=26563

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26564

   (26) https://bugs.python.org/issue?@action=redirect&bpo=26558

   (27) https://bugs.python.org/issue?@action=redirect&bpo=26516

   (28) https://bugs.python.org/issue?@action=redirect&bpo=26516

   (29) https://bugs.python.org/issue?@action=redirect&bpo=26516

   (30) https://bugs.python.org/issue?@action=redirect&bpo=26516

   (31) https://bugs.python.org/issue?@action=redirect&bpo=26464

   (32) https://bugs.python.org/issue?@action=redirect&bpo=22836

   (33) https://bugs.python.org/issue?@action=redirect&bpo=26302

   (34) https://bugs.python.org/issue?@action=redirect&bpo=26136

   (35) https://bugs.python.org/issue?@action=redirect&bpo=26204

   (36) https://bugs.python.org/issue?@action=redirect&bpo=4806

   (37) https://bugs.python.org/issue?@action=redirect&bpo=26146

   (38) https://bugs.python.org/issue?@action=redirect&bpo=23601

   (39) https://bugs.python.org/issue?@action=redirect&bpo=18018

   (40) https://bugs.python.org/issue?@action=redirect&bpo=25843

   (41) https://bugs.python.org/issue?@action=redirect&bpo=26107

   (42) https://bugs.python.org/issue?@action=redirect&bpo=26154

   (43) https://bugs.python.org/issue?@action=redirect&bpo=25791

   (44) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (45) https://bugs.python.org/issue?@action=redirect&bpo=25961

   (46) https://bugs.python.org/issue?@action=redirect&bpo=25973

   (47) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (48) https://bugs.python.org/issue?@action=redirect&bpo=20440

   (49) https://bugs.python.org/issue?@action=redirect&bpo=25766

   (50) https://bugs.python.org/issue?@action=redirect&bpo=25421

   (51) https://bugs.python.org/issue?@action=redirect&bpo=25709

   (52) https://bugs.python.org/issue?@action=redirect&bpo=5319

   (53) https://bugs.python.org/issue?@action=redirect&bpo=25485

   (54) https://bugs.python.org/issue?@action=redirect&bpo=24097

   (55) https://bugs.python.org/issue?@action=redirect&bpo=24731

   (56) https://bugs.python.org/issue?@action=redirect&bpo=25630

   (57) https://bugs.python.org/issue?@action=redirect&bpo=23564

   (58) https://bugs.python.org/issue?@action=redirect&bpo=25388

   (59) https://bugs.python.org/issue?@action=redirect&bpo=25462

   (60) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (61) https://bugs.python.org/issue?@action=redirect&bpo=24802

   (62) https://bugs.python.org/issue?@action=redirect&bpo=25555

   (63) https://bugs.python.org/issue?@action=redirect&bpo=24726

   (64) https://bugs.python.org/issue?@action=redirect&bpo=25449

   (65) https://bugs.python.org/issue?@action=redirect&bpo=25395

   (66) https://bugs.python.org/issue?@action=redirect&bpo=25401

   (67) https://bugs.python.org/issue?@action=redirect&bpo=25399

   (68) https://bugs.python.org/issue?@action=redirect&bpo=25274

   (69) https://bugs.python.org/issue?@action=redirect&bpo=24402

   (70) https://bugs.python.org/issue?@action=redirect&bpo=25349

   (71) https://bugs.python.org/issue?@action=redirect&bpo=24806

   (72) https://bugs.python.org/issue?@action=redirect&bpo=25301

   (73) https://bugs.python.org/issue?@action=redirect&bpo=24848

   (74) https://bugs.python.org/issue?@action=redirect&bpo=25267

   (75) https://bugs.python.org/issue?@action=redirect&bpo=25280

   (76) https://bugs.python.org/issue?@action=redirect&bpo=25227

   (77) https://bugs.python.org/issue?@action=redirect&bpo=25003

   (78) https://bugs.python.org/issue?@action=redirect&bpo=9232

   (79) https://bugs.python.org/issue?@action=redirect&bpo=24965

   (80) https://peps.python.org/pep-0498/

   (81) https://bugs.python.org/issue?@action=redirect&bpo=26478

   (82) https://bugs.python.org/issue?@action=redirect&bpo=26171

   (83) https://bugs.python.org/issue?@action=redirect&bpo=25660

   (84) https://bugs.python.org/issue?@action=redirect&bpo=26288

   (85) https://bugs.python.org/issue?@action=redirect&bpo=26289

   (86) https://bugs.python.org/issue?@action=redirect&bpo=26315

   (87) https://bugs.python.org/issue?@action=redirect&bpo=25887


File: python.info,  Node: Library<165>,  Next: IDLE<60>,  Prev: Core and Builtins<163>,  Up: Python 3 6 0 alpha 1

1.23.98.3 Library
.................

   - bpo-27057(1): Fix os.set_inheritable() on Android, ioctl() is
     blocked by SELinux and fails with EACCESS. The function now falls
     back to fcntl().  Patch written by Michał Bednarski.

   - bpo-27014(2): Fix infinite recursion using typing.py.  Thanks to
     Kalle Tuure!

   - bpo-27031(3): Removed dummy methods in Tkinter widget classes:
     tk_menuBar() and tk_bindForTraversal().

   - bpo-14132(4): Fix urllib.request redirect handling when the target
     only has a query string.  Original fix by Ján Janech.

   - bpo-17214(5): The “urllib.request” module now percent-encodes
     non-ASCII bytes found in redirect target URLs.  Some servers send
     Location header fields with non-ASCII bytes, but “http.client”
     requires the request target to be ASCII-encodable, otherwise a
     UnicodeEncodeError is raised.  Based on patch by Christian Heimes.

   - bpo-27033(6): The default value of the decode_data parameter for
     smtpd.SMTPChannel and smtpd.SMTPServer constructors is changed to
     False.

   - bpo-27034(7): Removed deprecated class asynchat.fifo.

   - bpo-26870(8): Added readline.set_auto_history(), which can stop
     entries being automatically added to the history list.  Based on
     patch by Tyler Crompton.

   - bpo-26039(9): zipfile.ZipFile.open() can now be used to write data
     into a ZIP file, as well as for extracting data.  Patch by Thomas
     Kluyver.

   - bpo-26892(10): Honor debuglevel flag in urllib.request.HTTPHandler.
     Patch contributed by Chi Hsuan Yen.

   - bpo-22274(11): In the subprocess module, allow stderr to be
     redirected to stdout even when stdout is not redirected.  Patch by
     Akira Li.

   - bpo-26807(12): mock_open ‘files’ no longer error on readline at end
     of file.  Patch from Yolanda Robla.

   - bpo-25745(13): Fixed leaking a userptr in curses panel destructor.

   - bpo-26977(14): Removed unnecessary, and ignored, call to sum of
     squares helper in statistics.pvariance.

   - bpo-26002(15): Use bisect in statistics.median instead of a linear
     search.  Patch by Upendra Kuma.

   - bpo-25974(16): Make use of new Decimal.as_integer_ratio() method in
     statistics module.  Patch by Stefan Krah.

   - bpo-26996(17): Add secrets module as described in PEP 506(18).

   - bpo-26881(19): The modulefinder module now supports extended opcode
     arguments.

   - bpo-23815(20): Fixed crashes related to directly created instances
     of types in _tkinter and curses.panel modules.

   - bpo-17765(21): weakref.ref() no longer silently ignores keyword
     arguments.  Patch by Georg Brandl.

   - bpo-26873(22): xmlrpc now raises ResponseError on unsupported type
     tags instead of silently return incorrect result.

   - bpo-26915(23): The __contains__ methods in the collections ABCs now
     check for identity before checking equality.  This better matches
     the behavior of the concrete classes, allows sensible handling of
     NaNs, and makes it easier to reason about container invariants.

   - bpo-26711(24): Fixed the comparison of plistlib.Data with other
     types.

   - bpo-24114(25): Fix an uninitialized variable in ‘ctypes.util’.  The
     bug only occurs on SunOS when the ctypes implementation searches
     for the ‘crle’ program.  Patch by Xiang Zhang.  Tested on SunOS by
     Kees Bos.

   - bpo-26864(26): In urllib.request, change the proxy bypass host
     checking against no_proxy to be case-insensitive, and to not match
     unrelated host names that happen to have a bypassed hostname as a
     suffix.  Patch by Xiang Zhang.

   - bpo-24902(27): Print server URL on http.server startup.  Initial
     patch by Felix Kaiser.

   - bpo-25788(28): fileinput.hook_encoded() now supports an “errors”
     argument for passing to open.  Original patch by Joseph Hackman.

   - bpo-26634(29): recursive_repr() now sets __qualname__ of wrapper.
     Patch by Xiang Zhang.

   - bpo-26804(30): urllib.request will prefer lower_case proxy
     environment variables over UPPER_CASE or Mixed_Case ones.  Patch
     contributed by Hans-Peter Jansen.

   - bpo-26837(31): assertSequenceEqual() now correctly outputs
     non-stringified differing items (like bytes in the -b mode).  This
     affects assertListEqual() and assertTupleEqual().

   - bpo-26041(32): Remove “will be removed in Python 3.7” from
     deprecation messages of platform.dist() and
     platform.linux_distribution().  Patch by Kumaripaba Miyurusara
     Athukorala.

   - bpo-26822(33): itemgetter, attrgetter and methodcaller objects no
     longer silently ignore keyword arguments.

   - bpo-26733(34): Disassembling a class now disassembles class and
     static methods.  Patch by Xiang Zhang.

   - bpo-26801(35): Fix error handling in *note
     shutil.get_terminal_size(): 1147, catch *note AttributeError: 34e.
     instead of *note NameError: 442.  Patch written by Emanuel Barry.

   - bpo-24838(36): tarfile’s ustar and gnu formats now correctly
     calculate name and link field limits for multibyte character
     encodings like utf-8.

   - bpo-26717(37): Stop encoding Latin-1-ized WSGI paths with UTF-8.
     Patch by Anthony Sottile.

   - bpo-26782(38): Add STARTUPINFO to subprocess.__all__ on Windows.

   - bpo-26404(39): Add context manager to socketserver.  Patch by Aviv
     Palivoda.

   - bpo-26735(40): Fix *note os.urandom(): 526. on Solaris 11.3 and
     newer when reading more than 1,024 bytes: call ‘getrandom()’
     multiple times with a limit of 1024 bytes per call.

   - bpo-26585(41): Eliminate http.server._quote_html() and use
     html.escape(quote=False).  Patch by Xiang Zhang.

   - bpo-26685(42): Raise OSError if closing a socket fails.

   - bpo-16329(43): Add .webm to mimetypes.types_map.  Patch by
     Giampaolo Rodola’.

   - bpo-13952(44): Add .csv to mimetypes.types_map.  Patch by Geoff
     Wilson.

   - bpo-26587(45): the site module now allows .pth files to specify
     files to be added to sys.path (e.g.  zip files).

   - bpo-25609(46): Introduce contextlib.AbstractContextManager and
     typing.ContextManager.

   - bpo-26709(47): Fixed Y2038 problem in loading binary PLists.

   - bpo-23735(48): Handle terminal resizing with Readline 6.3+ by
     installing our own SIGWINCH handler.  Patch by Eric Price.

   - bpo-25951(49): Change SSLSocket.sendall() to return None, as
     explicitly documented for plain socket objects.  Patch by Aviv
     Palivoda.

   - bpo-26586(50): In http.server, respond with “413 Request header
     fields too large” if there are too many header fields to parse,
     rather than killing the connection and raising an unhandled
     exception.  Patch by Xiang Zhang.

   - bpo-26676(51): Added missing XMLPullParser to ElementTree.__all__.

   - bpo-22854(52): Change BufferedReader.writable() and
     BufferedWriter.readable() to always return False.

   - bpo-26492(53): Exhausted iterator of array.array now conforms with
     the behavior of iterators of other mutable sequences: it lefts
     exhausted even if iterated array is extended.

   - bpo-26641(54): doctest.DocFileTest and doctest.testfile() now
     support packages (module splitted into multiple directories) for
     the package parameter.

   - bpo-25195(55): Fix a regression in mock.MagicMock.  _Call is a
     subclass of tuple (changeset 3603bae63c13 only works for classes)
     so we need to implement __ne__ ourselves.  Patch by Andrew Plummer.

   - bpo-26644(56): Raise ValueError rather than SystemError when a
     negative length is passed to SSLSocket.recv() or read().

   - bpo-23804(57): Fix SSL recv(0) and read(0) methods to return zero
     bytes instead of up to 1024.

   - bpo-26616(58): Fixed a bug in datetime.astimezone() method.

   - bpo-26637(59): The *note importlib: 77. module now emits an *note
     ImportError: 41c. rather than a *note TypeError: 2c3. if *note
     __import__(): 8dd. is tried during the Python shutdown process but
     *note sys.path: 3b7. is already cleared (set to ‘None’).

   - bpo-21925(60): *note warnings.formatwarning(): 1ba6. now catches
     exceptions when calling *note linecache.getline(): e56. and *note
     tracemalloc.get_object_traceback(): 1cea. to be able to log *note
     ResourceWarning: 244. emitted late during the Python shutdown
     process.

   - bpo-23848(61): On Windows, faulthandler.enable() now also installs
     an exception handler to dump the traceback of all Python threads on
     any Windows exception, not only on UNIX signals (SIGSEGV, SIGFPE,
     SIGABRT).

   - bpo-26530(62): Add C functions ‘_PyTraceMalloc_Track()’ and
     ‘_PyTraceMalloc_Untrack()’ to track memory blocks using the *note
     tracemalloc: ff. module.  Add ‘_PyTraceMalloc_GetTraceback()’ to
     get the traceback of an object.

   - bpo-26588(63): The _tracemalloc now supports tracing memory
     allocations of multiple address spaces (domains).

   - bpo-24266(64): Ctrl+C during Readline history search now cancels
     the search mode when compiled with Readline 7.

   - bpo-26590(65): Implement a safe finalizer for the _socket.socket
     type.  It now releases the GIL to close the socket.

   - bpo-18787(66): spwd.getspnam() now raises a PermissionError if the
     user doesn’t have privileges.

   - bpo-26560(67): Avoid potential ValueError in
     BaseHandler.start_response.  Initial patch by Peter Inglesby.

   - bpo-26567(68): Add a new function *note PyErr_ResourceWarning():
     d3f. function to pass the destroyed object.  Add a 'source'
     attribute to ‘warnings.WarningMessage’.  Add
     warnings._showwarnmsg() which uses tracemalloc to get the traceback
     where source object was allocated.

   - bpo-26569(69): Fix *note pyclbr.readmodule(): 831. and *note
     pyclbr.readmodule_ex(): 832. to support importing packages.

   - bpo-26499(70): Account for remaining Content-Length in
     HTTPResponse.readline() and read1().  Based on patch by Silent
     Ghost.  Also document that HTTPResponse now supports these methods.

   - bpo-25320(71): Handle sockets in directories unittest discovery is
     scanning.  Patch from Victor van den Elzen.

   - bpo-16181(72): cookiejar.http2time() now returns None if year is
     higher than datetime.MAXYEAR.

   - bpo-26513(73): Fixes platform module detection of Windows Server

   - bpo-23718(74): Fixed parsing time in week 0 before Jan 1.  Original
     patch by Tamás Bence Gedai.

   - bpo-26323(75): Add Mock.assert_called() and
     Mock.assert_called_once() methods to unittest.mock.  Patch written
     by Amit Saha.

   - bpo-20589(76): Invoking Path.owner() and Path.group() on Windows
     now raise NotImplementedError instead of ImportError.

   - bpo-26177(77): Fixed the keys() method for Canvas and Scrollbar
     widgets.

   - bpo-15068(78): Got rid of excessive buffering in fileinput.  The
     bufsize parameter is now deprecated and ignored.

   - bpo-19475(79): Added an optional argument timespec to the datetime
     isoformat() method to choose the precision of the time component.

   - bpo-2202(80): Fix UnboundLocalError in
     AbstractDigestAuthHandler.get_algorithm_impls.  Initial patch by
     Mathieu Dupuy.

   - bpo-26167(81): Minimized overhead in copy.copy() and
     copy.deepcopy().  Optimized copying and deepcopying bytearrays,
     NotImplemented, slices, short lists, tuples, dicts, sets.

   - bpo-25718(82): Fixed pickling and copying the accumulate() iterator
     with total is None.

   - bpo-26475(83): Fixed debugging output for regular expressions with
     the (?x) flag.

   - bpo-26482(84): Allowed pickling recursive dequeues.

   - bpo-26335(85): Make mmap.write() return the number of bytes written
     like other write methods.  Patch by Jakub Stasiak.

   - bpo-26457(86): Fixed the subnets() methods in IP network classes
     for the case when resulting prefix length is equal to maximal
     prefix length.  Based on patch by Xiang Zhang.

   - bpo-26385(87): Remove the file if the internal open() call in
     NamedTemporaryFile() fails.  Patch by Silent Ghost.

   - bpo-26402(88): Fix XML-RPC client to retry when the server shuts
     down a persistent connection.  This was a regression related to the
     new http.client.RemoteDisconnected exception in 3.5.0a4.

   - bpo-25913(89): Leading ‘<~’ is optional now in base64.a85decode()
     with adobe=True.  Patch by Swati Jaiswal.

   - bpo-26186(90): Remove an invalid type check in
     importlib.util.LazyLoader.

   - bpo-26367(91): importlib.__import__() raises ImportError like
     builtins.__import__() when ‘level’ is specified but without an
     accompanying package specified.

   - bpo-26309(92): In the “socketserver” module, shut down the request
     (closing the connected socket) when verify_request() returns false.
     Patch by Aviv Palivoda.

   - bpo-23430(93): Change the socketserver module to only catch
     exceptions raised from a request handler that are derived from
     Exception (instead of BaseException).  Therefore SystemExit and
     KeyboardInterrupt no longer trigger the handle_error() method, and
     will now to stop a single-threaded server.

   - bpo-25995(94): os.walk() no longer uses FDs proportional to the
     tree depth.

   - bpo-25994(95): Added the close() method and the support of the
     context manager protocol for the os.scandir() iterator.

   - bpo-23992(96): multiprocessing: make MapResult not fail-fast upon
     exception.

   - bpo-26243(97): Support keyword arguments to zlib.compress().  Patch
     by Aviv Palivoda.

   - bpo-26117(98): The os.scandir() iterator now closes file descriptor
     not only when the iteration is finished, but when it was failed
     with error.

   - bpo-25949(99): __dict__ for an OrderedDict instance is now created
     only when needed.

   - bpo-25911(100): Restored support of bytes paths in os.walk() on
     Windows.

   - bpo-26045(101): Add UTF-8 suggestion to error message when posting
     a non-Latin-1 string with http.client.

   - bpo-26039(102): Added zipfile.ZipInfo.from_file() and
     zipinfo.ZipInfo.is_dir().  Patch by Thomas Kluyver.

   - bpo-12923(103): Reset FancyURLopener’s redirect counter even if
     there is an exception.  Based on patches by Brian Brazil and Daniel
     Rocco.

   - bpo-25945(104): Fixed a crash when unpickle the functools.partial
     object with wrong state.  Fixed a leak in failed functools.partial
     constructor.  “args” and “keywords” attributes of functools.partial
     have now always types tuple and dict correspondingly.

   - bpo-26202(105): copy.deepcopy() now correctly copies range()
     objects with non-atomic attributes.

   - bpo-23076(106): Path.glob() now raises a ValueError if it’s called
     with an invalid pattern.  Patch by Thomas Nyberg.

   - bpo-19883(107): Fixed possible integer overflows in zipimport.

   - bpo-26227(108): On Windows, getnameinfo(), gethostbyaddr() and
     gethostbyname_ex() functions of the socket module now decode the
     hostname from the ANSI code page rather than UTF-8.

   - bpo-26099(109): The site module now writes an error into stderr if
     sitecustomize module can be imported but executing the module raise
     an ImportError.  Same change for usercustomize.

   - bpo-26147(110): xmlrpc now works with strings not encodable with
     used non-UTF-8 encoding.

   - bpo-25935(111): Garbage collector now breaks reference loops with
     OrderedDict.

   - bpo-16620(112): Fixed AttributeError in msilib.Directory.glob().

   - bpo-26013(113): Added compatibility with broken protocol 2 pickles
     created in old Python 3 versions (3.4.3 and lower).

   - bpo-26129(114): Deprecated accepting non-integers in
     grp.getgrgid().

   - bpo-25850(115): Use cross-compilation by default for 64-bit
     Windows.

   - bpo-25822(116): Add docstrings to the fields of urllib.parse
     results.  Patch contributed by Swati Jaiswal.

   - bpo-22642(117): Convert trace module option parsing mechanism to
     argparse.  Patch contributed by SilentGhost.

   - bpo-24705(118): Fix sysconfig._parse_makefile not expanding ${}
     vars appearing before $() vars.

   - bpo-26069(119): Remove the deprecated apis in the trace module.

   - bpo-22138(120): Fix mock.patch behavior when patching descriptors.
     Restore original values after patching.  Patch contributed by Sean
     McCully.

   - bpo-25672(121): In the ssl module, enable the
     SSL_MODE_RELEASE_BUFFERS mode option if it is safe to do so.

   - bpo-26012(122): Don’t traverse into symlinks for ‘**’ pattern in
     pathlib.Path.[r]glob().

   - bpo-24120(123): Ignore PermissionError when traversing a tree with
     pathlib.Path.[r]glob().  Patch by Ulrich Petri.

   - bpo-21815(124): Accept ] characters in the data portion of imap
     responses, in order to handle the flags with square brackets
     accepted and produced by servers such as gmail.

   - bpo-25447(125): fileinput now uses sys.stdin as-is if it does not
     have a buffer attribute (restores backward compatibility).

   - bpo-25971(126): Optimized creating Fractions from floats by 2 times
     and from Decimals by 3 times.

   - bpo-25802(127): Document as deprecated the remaining
     implementations of importlib.abc.Loader.load_module().

   - bpo-25928(128): Add Decimal.as_integer_ratio().

   - bpo-25447(129): Copying the lru_cache() wrapper object now always
     works, independently from the type of the wrapped object (by
     returning the original object unchanged).

   - bpo-25768(130): Have the functions in compileall return booleans
     instead of ints and add proper documentation and tests for the
     return values.

   - bpo-24103(131): Fixed possible use after free in
     ElementTree.XMLPullParser.

   - bpo-25860(132): os.fwalk() no longer skips remaining directories
     when error occurs.  Original patch by Samson Lee.

   - bpo-25914(133): Fixed and simplified OrderedDict.__sizeof__.

   - bpo-25869(134): Optimized deepcopying ElementTree; it is now 20
     times faster.

   - bpo-25873(135): Optimized iterating ElementTree.  Iterating
     elements Element.iter() is now 40% faster, iterating text
     Element.itertext() is now up to 2.5 times faster.

   - bpo-25902(136): Fixed various refcount issues in ElementTree
     iteration.

   - bpo-22227(137): The TarFile iterator is reimplemented using
     generator.  This implementation is simpler that using class.

   - bpo-25638(138): Optimized ElementTree.iterparse(); it is now 2x
     faster.  Optimized ElementTree parsing; it is now 10% faster.

   - bpo-25761(139): Improved detecting errors in broken pickle data.

   - bpo-25717(140): Restore the previous behaviour of tolerating most
     fstat() errors when opening files.  This was a regression in 3.5a1,
     and stopped anonymous temporary files from working in special
     cases.

   - bpo-24903(141): Fix regression in number of arguments compileall
     accepts when ‘-d’ is specified.  The check on the number of
     arguments has been dropped completely as it never worked correctly
     anyway.

   - bpo-25764(142): In the subprocess module, preserve any exception
     caused by fork() failure when preexec_fn is used.

   - bpo-25771(143): Tweak the exception message for
     importlib.util.resolve_name() when ‘package’ isn’t specified but
     necessary.

   - bpo-6478(144): _strptime’s regexp cache now is reset after changing
     timezone with time.tzset().

   - bpo-14285(145): When executing a package with the “python -m
     package” option, and package initialization fails, a proper
     traceback is now reported.  The “runpy” module now lets exceptions
     from package initialization pass back to the caller, rather than
     raising ImportError.

   - bpo-19771(146): Also in runpy and the “-m” option, omit the
     irrelevant message “… is a package and cannot be directly executed”
     if the package could not even be initialized (e.g.  due to a bad
     ‘*.pyc’ file).

   - bpo-25177(147): Fixed problem with the mean of very small and very
     large numbers.  As a side effect, statistics.mean and
     statistics.variance should be significantly faster.

   - bpo-25718(148): Fixed copying object with state with boolean value
     is false.

   - bpo-10131(149): Fixed deep copying of minidom documents.  Based on
     patch by Marian Ganisin.

   - bpo-7990(150): dir() on ElementTree.Element now lists properties:
     “tag”, “text”, “tail” and “attrib”.  Original patch by Santoso
     Wijaya.

   - bpo-25725(151): Fixed a reference leak in pickle.loads() when
     unpickling invalid data including tuple instructions.

   - bpo-25663(152): In the Readline completer, avoid listing duplicate
     global names, and search the global namespace before searching
     builtins.

   - bpo-25688(153): Fixed file leak in ElementTree.iterparse() raising
     an error.

   - bpo-23914(154): Fixed SystemError raised by unpickler on broken
     pickle data.

   - bpo-25691(155): Fixed crash on deleting ElementTree.Element
     attributes.

   - bpo-25624(156): ZipFile now always writes a ZIP_STORED header for
     directory entries.  Patch by Dingyuan Wang.

   - bpo-25626(157): Change three zlib functions to accept sizes that
     fit in Py_ssize_t, but internally cap those sizes to UINT_MAX. This
     resolves a regression in 3.5 where GzipFile.read() failed to read
     chunks larger than 2 or 4 GiB. The change affects the
     zlib.Decompress.decompress() max_length parameter, the
     zlib.decompress() bufsize parameter, and the
     zlib.Decompress.flush() length parameter.

   - bpo-25583(158): Avoid incorrect errors raised by
     os.makedirs(exist_ok=True) when the OS gives priority to errors
     such as EACCES over EEXIST.

   - bpo-25593(159): Change semantics of EventLoop.stop() in asyncio.

   - bpo-6973(160): When we know a subprocess.Popen process has died, do
     not allow the send_signal(), terminate(), or kill() methods to do
     anything as they could potentially signal a different process.

   - bpo-23883(161): Added missing APIs to __all__ to match the
     documented APIs for the following modules: calendar, csv, enum,
     fileinput, ftplib, logging, optparse, tarfile, threading and wave.
     Also added a test.support.check__all__() helper.  Patches by Jacek
     Kołodziej, Mauro S. M. Rodrigues and Joel Taddei.

   - bpo-25590(162): In the Readline completer, only call getattr() once
     per attribute.  Also complete names of attributes such as
     properties and slots which are listed by dir() but not yet created
     on an instance.

   - bpo-25498(163): Fix a crash when garbage-collecting ctypes objects
     created by wrapping a memoryview.  This was a regression made in
     3.5a1.  Based on patch by Eryksun.

   - bpo-25584(164): Added “escape” to the __all__ list in the glob
     module.

   - bpo-25584(165): Fixed recursive glob() with patterns starting with
     ‘**’.

   - bpo-25446(166): Fix regression in smtplib’s AUTH LOGIN support.

   - bpo-18010(167): Fix the pydoc web server’s module search function
     to handle exceptions from importing packages.

   - bpo-25554(168): Got rid of circular references in regular
     expression parsing.

   - bpo-18973(169): Command-line interface of the calendar module now
     uses argparse instead of optparse.

   - bpo-25510(170): fileinput.FileInput.readline() now returns b’’
     instead of ‘’ at the end if the FileInput was opened with binary
     mode.  Patch by Ryosuke Ito.

   - bpo-25503(171): Fixed inspect.getdoc() for inherited docstrings of
     properties.  Original patch by John Mark Vandenberg.

   - bpo-25515(172): Always use os.urandom as a source of randomness in
     uuid.uuid4.

   - bpo-21827(173): Fixed textwrap.dedent() for the case when largest
     common whitespace is a substring of smallest leading whitespace.
     Based on patch by Robert Li.

   - bpo-25447(174): The lru_cache() wrapper objects now can be copied
     and pickled (by returning the original object unchanged).

   - bpo-25390(175): typing: Don’t crash on Union[str, Pattern].

   - bpo-25441(176): asyncio: Raise error from drain() when socket is
     closed.

   - bpo-25410(177): Cleaned up and fixed minor bugs in C implementation
     of OrderedDict.

   - bpo-25411(178): Improved Unicode support in SMTPHandler through
     better use of the email package.  Thanks to user simon04 for the
     patch.

   - Move the imp module from a PendingDeprecationWarning to
     DeprecationWarning.

   - bpo-25407(179): Remove mentions of the formatter module being
     removed in Python 3.6.

   - bpo-25406(180): Fixed a bug in C implementation of
     OrderedDict.move_to_end() that caused segmentation fault or hang in
     iterating after moving several items to the start of ordered dict.

   - bpo-25382(181): pickletools.dis() now outputs implicit memo index
     for the MEMOIZE opcode.

   - bpo-25357(182): Add an optional newline parameter to
     binascii.b2a_base64().  base64.b64encode() uses it to avoid a
     memory copy.

   - bpo-24164(183): Objects that need calling ‘__new__’ with keyword
     arguments, can now be pickled using pickle protocols older than
     protocol version 4.

   - bpo-25364(184): zipfile now works in threads disabled builds.

   - bpo-25328(185): smtpd’s SMTPChannel now correctly raises a
     ValueError if both decode_data and enable_SMTPUTF8 are set to true.

   - bpo-16099(186): RobotFileParser now supports Crawl-delay and
     Request-rate extensions.  Patch by Nikolay Bogoychev.

   - bpo-25316(187): distutils raises OSError instead of
     DistutilsPlatformError when MSVC is not installed.

   - bpo-25380(188): Fixed protocol for the STACK_GLOBAL opcode in
     pickletools.opcodes.

   - bpo-23972(189): Updates asyncio datagram create method allowing
     reuseport and reuseaddr socket options to be set prior to binding
     the socket.  Mirroring the existing asyncio create_server method
     the reuseaddr option for datagram sockets defaults to True if the
     O/S is ‘posix’ (except if the platform is Cygwin).  Patch by Chris
     Laws.

   - bpo-25304(190): Add asyncio.run_coroutine_threadsafe().  This lets
     you submit a coroutine to a loop from another thread, returning a
     concurrent.futures.Future.  By Vincent Michel.

   - bpo-25232(191): Fix CGIRequestHandler to split the query from the
     URL at the first question mark (?)  rather than the last.  Patch
     from Xiang Zhang.

   - bpo-24657(192): Prevent CGIRequestHandler from collapsing slashes
     in the query part of the URL as if it were a path.  Patch from
     Xiang Zhang.

   - bpo-25287(193): Don’t add crypt.METHOD_CRYPT to crypt.methods if
     it’s not supported.  Check if it is supported, it may not be
     supported on OpenBSD for example.

   - bpo-23600(194): Default implementation of tzinfo.fromutc() was
     returning wrong results in some cases.

   - bpo-25203(195): Failed readline.set_completer_delims() no longer
     left the module in inconsistent state.

   - bpo-25011(196): rlcompleter now omits private and special attribute
     names unless the prefix starts with underscores.

   - bpo-25209(197): rlcompleter now can add a space or a colon after
     completed keyword.

   - bpo-22241(198): timezone.utc name is now plain ‘UTC’, not
     ‘UTC-00:00’.

   - bpo-23517(199): fromtimestamp() and utcfromtimestamp() methods of
     datetime.datetime now round microseconds to nearest with ties going
     to nearest even integer (ROUND_HALF_EVEN), as round(float), instead
     of rounding towards -Infinity (ROUND_FLOOR).

   - bpo-23552(200): Timeit now warns when there is substantial (4x)
     variance between best and worst times.  Patch from Serhiy
     Storchaka.

   - bpo-24633(201): site-packages/README -> README.txt.

   - bpo-24879(202): help() and pydoc can now list named tuple fields in
     the order they were defined rather than alphabetically.  The
     ordering is determined by the _fields attribute if present.

   - bpo-24874(203): Improve speed of itertools.cycle() and make its
     pickle more compact.

   - Fix crash in itertools.cycle.__setstate__() when the first argument
     wasn’t a list.

   - bpo-20059(204): urllib.parse raises ValueError on all invalid
     ports.  Patch by Martin Panter.

   - bpo-24360(205): Improve __repr__ of argparse.Namespace() for
     invalid identifiers.  Patch by Matthias Bussonnier.

   - bpo-23426(206): run_setup was broken in distutils.  Patch from
     Alexander Belopolsky.

   - bpo-13938(207): 2to3 converts StringTypes to a tuple.  Patch from
     Mark Hammond.

   - bpo-2091(208): open() accepted a ‘U’ mode string containing ‘+’,
     but ‘U’ can only be used with ‘r’.  Patch from Jeff Balogh and John
     O’Connor.

   - bpo-8585(209): improved tests for zipimporter2.  Patch from Mark
     Lawrence.

   - bpo-18622(210): unittest.mock.mock_open().reset_mock would recurse
     infinitely.  Patch from Nicola Palumbo and Laurent De Buyst.

   - bpo-24426(211): Fast searching optimization in regular expressions
     now works for patterns that starts with capturing groups.  Fast
     searching optimization now can’t be disabled at compile time.

   - bpo-23661(212): unittest.mock side_effects can now be exceptions
     again.  This was a regression vs Python 3.4.  Patch from Ignacio
     Rossi

   - bpo-13248(213): Remove deprecated inspect.getmoduleinfo function.

   - bpo-25578(214): Fix (another) memory leak in
     SSLSocket.getpeercer().

   - bpo-25530(215): Disable the vulnerable SSLv3 protocol by default
     when creating ssl.SSLContext.

   - bpo-25569(216): Fix memory leak in SSLSocket.getpeercert().

   - bpo-25471(217): Sockets returned from accept() shouldn’t appear to
     be nonblocking.

   - bpo-25319(218): When threading.Event is reinitialized, the
     underlying condition should use a regular lock rather than a
     recursive lock.

   - Skip getaddrinfo if host is already resolved.  Patch by A. Jesse
     Jiryu Davis.

   - bpo-26050(219): Add asyncio.StreamReader.readuntil() method.  Patch
     by Марк Коренберг.

   - bpo-25924(220): Avoid unnecessary serialization of getaddrinfo(3)
     calls on OS X versions 10.5 or higher.  Original patch by A. Jesse
     Jiryu Davis.

   - bpo-26406(221): Avoid unnecessary serialization of getaddrinfo(3)
     calls on current versions of OpenBSD and NetBSD. Patch by A. Jesse
     Jiryu Davis.

   - bpo-26848(222): Fix asyncio/subprocess.communicate() to handle
     empty input.  Patch by Jack O’Connor.

   - bpo-27040(223): Add loop.get_exception_handler method

   - bpo-27041(224): asyncio: Add loop.create_future method

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27057

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27014

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27031

   (4) https://bugs.python.org/issue?@action=redirect&bpo=14132

   (5) https://bugs.python.org/issue?@action=redirect&bpo=17214

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27033

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27034

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26870

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26039

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26892

   (11) https://bugs.python.org/issue?@action=redirect&bpo=22274

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26807

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25745

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26977

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26002

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25974

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26996

   (18) https://peps.python.org/pep-0506/

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26881

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23815

   (21) https://bugs.python.org/issue?@action=redirect&bpo=17765

   (22) https://bugs.python.org/issue?@action=redirect&bpo=26873

   (23) https://bugs.python.org/issue?@action=redirect&bpo=26915

   (24) https://bugs.python.org/issue?@action=redirect&bpo=26711

   (25) https://bugs.python.org/issue?@action=redirect&bpo=24114

   (26) https://bugs.python.org/issue?@action=redirect&bpo=26864

   (27) https://bugs.python.org/issue?@action=redirect&bpo=24902

   (28) https://bugs.python.org/issue?@action=redirect&bpo=25788

   (29) https://bugs.python.org/issue?@action=redirect&bpo=26634

   (30) https://bugs.python.org/issue?@action=redirect&bpo=26804

   (31) https://bugs.python.org/issue?@action=redirect&bpo=26837

   (32) https://bugs.python.org/issue?@action=redirect&bpo=26041

   (33) https://bugs.python.org/issue?@action=redirect&bpo=26822

   (34) https://bugs.python.org/issue?@action=redirect&bpo=26733

   (35) https://bugs.python.org/issue?@action=redirect&bpo=26801

   (36) https://bugs.python.org/issue?@action=redirect&bpo=24838

   (37) https://bugs.python.org/issue?@action=redirect&bpo=26717

   (38) https://bugs.python.org/issue?@action=redirect&bpo=26782

   (39) https://bugs.python.org/issue?@action=redirect&bpo=26404

   (40) https://bugs.python.org/issue?@action=redirect&bpo=26735

   (41) https://bugs.python.org/issue?@action=redirect&bpo=26585

   (42) https://bugs.python.org/issue?@action=redirect&bpo=26685

   (43) https://bugs.python.org/issue?@action=redirect&bpo=16329

   (44) https://bugs.python.org/issue?@action=redirect&bpo=13952

   (45) https://bugs.python.org/issue?@action=redirect&bpo=26587

   (46) https://bugs.python.org/issue?@action=redirect&bpo=25609

   (47) https://bugs.python.org/issue?@action=redirect&bpo=26709

   (48) https://bugs.python.org/issue?@action=redirect&bpo=23735

   (49) https://bugs.python.org/issue?@action=redirect&bpo=25951

   (50) https://bugs.python.org/issue?@action=redirect&bpo=26586

   (51) https://bugs.python.org/issue?@action=redirect&bpo=26676

   (52) https://bugs.python.org/issue?@action=redirect&bpo=22854

   (53) https://bugs.python.org/issue?@action=redirect&bpo=26492

   (54) https://bugs.python.org/issue?@action=redirect&bpo=26641

   (55) https://bugs.python.org/issue?@action=redirect&bpo=25195

   (56) https://bugs.python.org/issue?@action=redirect&bpo=26644

   (57) https://bugs.python.org/issue?@action=redirect&bpo=23804

   (58) https://bugs.python.org/issue?@action=redirect&bpo=26616

   (59) https://bugs.python.org/issue?@action=redirect&bpo=26637

   (60) https://bugs.python.org/issue?@action=redirect&bpo=21925

   (61) https://bugs.python.org/issue?@action=redirect&bpo=23848

   (62) https://bugs.python.org/issue?@action=redirect&bpo=26530

   (63) https://bugs.python.org/issue?@action=redirect&bpo=26588

   (64) https://bugs.python.org/issue?@action=redirect&bpo=24266

   (65) https://bugs.python.org/issue?@action=redirect&bpo=26590

   (66) https://bugs.python.org/issue?@action=redirect&bpo=18787

   (67) https://bugs.python.org/issue?@action=redirect&bpo=26560

   (68) https://bugs.python.org/issue?@action=redirect&bpo=26567

   (69) https://bugs.python.org/issue?@action=redirect&bpo=26569

   (70) https://bugs.python.org/issue?@action=redirect&bpo=26499

   (71) https://bugs.python.org/issue?@action=redirect&bpo=25320

   (72) https://bugs.python.org/issue?@action=redirect&bpo=16181

   (73) https://bugs.python.org/issue?@action=redirect&bpo=26513

   (74) https://bugs.python.org/issue?@action=redirect&bpo=23718

   (75) https://bugs.python.org/issue?@action=redirect&bpo=26323

   (76) https://bugs.python.org/issue?@action=redirect&bpo=20589

   (77) https://bugs.python.org/issue?@action=redirect&bpo=26177

   (78) https://bugs.python.org/issue?@action=redirect&bpo=15068

   (79) https://bugs.python.org/issue?@action=redirect&bpo=19475

   (80) https://bugs.python.org/issue?@action=redirect&bpo=2202

   (81) https://bugs.python.org/issue?@action=redirect&bpo=26167

   (82) https://bugs.python.org/issue?@action=redirect&bpo=25718

   (83) https://bugs.python.org/issue?@action=redirect&bpo=26475

   (84) https://bugs.python.org/issue?@action=redirect&bpo=26482

   (85) https://bugs.python.org/issue?@action=redirect&bpo=26335

   (86) https://bugs.python.org/issue?@action=redirect&bpo=26457

   (87) https://bugs.python.org/issue?@action=redirect&bpo=26385

   (88) https://bugs.python.org/issue?@action=redirect&bpo=26402

   (89) https://bugs.python.org/issue?@action=redirect&bpo=25913

   (90) https://bugs.python.org/issue?@action=redirect&bpo=26186

   (91) https://bugs.python.org/issue?@action=redirect&bpo=26367

   (92) https://bugs.python.org/issue?@action=redirect&bpo=26309

   (93) https://bugs.python.org/issue?@action=redirect&bpo=23430

   (94) https://bugs.python.org/issue?@action=redirect&bpo=25995

   (95) https://bugs.python.org/issue?@action=redirect&bpo=25994

   (96) https://bugs.python.org/issue?@action=redirect&bpo=23992

   (97) https://bugs.python.org/issue?@action=redirect&bpo=26243

   (98) https://bugs.python.org/issue?@action=redirect&bpo=26117

   (99) https://bugs.python.org/issue?@action=redirect&bpo=25949

   (100) https://bugs.python.org/issue?@action=redirect&bpo=25911

   (101) https://bugs.python.org/issue?@action=redirect&bpo=26045

   (102) https://bugs.python.org/issue?@action=redirect&bpo=26039

   (103) https://bugs.python.org/issue?@action=redirect&bpo=12923

   (104) https://bugs.python.org/issue?@action=redirect&bpo=25945

   (105) https://bugs.python.org/issue?@action=redirect&bpo=26202

   (106) https://bugs.python.org/issue?@action=redirect&bpo=23076

   (107) https://bugs.python.org/issue?@action=redirect&bpo=19883

   (108) https://bugs.python.org/issue?@action=redirect&bpo=26227

   (109) https://bugs.python.org/issue?@action=redirect&bpo=26099

   (110) https://bugs.python.org/issue?@action=redirect&bpo=26147

   (111) https://bugs.python.org/issue?@action=redirect&bpo=25935

   (112) https://bugs.python.org/issue?@action=redirect&bpo=16620

   (113) https://bugs.python.org/issue?@action=redirect&bpo=26013

   (114) https://bugs.python.org/issue?@action=redirect&bpo=26129

   (115) https://bugs.python.org/issue?@action=redirect&bpo=25850

   (116) https://bugs.python.org/issue?@action=redirect&bpo=25822

   (117) https://bugs.python.org/issue?@action=redirect&bpo=22642

   (118) https://bugs.python.org/issue?@action=redirect&bpo=24705

   (119) https://bugs.python.org/issue?@action=redirect&bpo=26069

   (120) https://bugs.python.org/issue?@action=redirect&bpo=22138

   (121) https://bugs.python.org/issue?@action=redirect&bpo=25672

   (122) https://bugs.python.org/issue?@action=redirect&bpo=26012

   (123) https://bugs.python.org/issue?@action=redirect&bpo=24120

   (124) https://bugs.python.org/issue?@action=redirect&bpo=21815

   (125) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (126) https://bugs.python.org/issue?@action=redirect&bpo=25971

   (127) https://bugs.python.org/issue?@action=redirect&bpo=25802

   (128) https://bugs.python.org/issue?@action=redirect&bpo=25928

   (129) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (130) https://bugs.python.org/issue?@action=redirect&bpo=25768

   (131) https://bugs.python.org/issue?@action=redirect&bpo=24103

   (132) https://bugs.python.org/issue?@action=redirect&bpo=25860

   (133) https://bugs.python.org/issue?@action=redirect&bpo=25914

   (134) https://bugs.python.org/issue?@action=redirect&bpo=25869

   (135) https://bugs.python.org/issue?@action=redirect&bpo=25873

   (136) https://bugs.python.org/issue?@action=redirect&bpo=25902

   (137) https://bugs.python.org/issue?@action=redirect&bpo=22227

   (138) https://bugs.python.org/issue?@action=redirect&bpo=25638

   (139) https://bugs.python.org/issue?@action=redirect&bpo=25761

   (140) https://bugs.python.org/issue?@action=redirect&bpo=25717

   (141) https://bugs.python.org/issue?@action=redirect&bpo=24903

   (142) https://bugs.python.org/issue?@action=redirect&bpo=25764

   (143) https://bugs.python.org/issue?@action=redirect&bpo=25771

   (144) https://bugs.python.org/issue?@action=redirect&bpo=6478

   (145) https://bugs.python.org/issue?@action=redirect&bpo=14285

   (146) https://bugs.python.org/issue?@action=redirect&bpo=19771

   (147) https://bugs.python.org/issue?@action=redirect&bpo=25177

   (148) https://bugs.python.org/issue?@action=redirect&bpo=25718

   (149) https://bugs.python.org/issue?@action=redirect&bpo=10131

   (150) https://bugs.python.org/issue?@action=redirect&bpo=7990

   (151) https://bugs.python.org/issue?@action=redirect&bpo=25725

   (152) https://bugs.python.org/issue?@action=redirect&bpo=25663

   (153) https://bugs.python.org/issue?@action=redirect&bpo=25688

   (154) https://bugs.python.org/issue?@action=redirect&bpo=23914

   (155) https://bugs.python.org/issue?@action=redirect&bpo=25691

   (156) https://bugs.python.org/issue?@action=redirect&bpo=25624

   (157) https://bugs.python.org/issue?@action=redirect&bpo=25626

   (158) https://bugs.python.org/issue?@action=redirect&bpo=25583

   (159) https://bugs.python.org/issue?@action=redirect&bpo=25593

   (160) https://bugs.python.org/issue?@action=redirect&bpo=6973

   (161) https://bugs.python.org/issue?@action=redirect&bpo=23883

   (162) https://bugs.python.org/issue?@action=redirect&bpo=25590

   (163) https://bugs.python.org/issue?@action=redirect&bpo=25498

   (164) https://bugs.python.org/issue?@action=redirect&bpo=25584

   (165) https://bugs.python.org/issue?@action=redirect&bpo=25584

   (166) https://bugs.python.org/issue?@action=redirect&bpo=25446

   (167) https://bugs.python.org/issue?@action=redirect&bpo=18010

   (168) https://bugs.python.org/issue?@action=redirect&bpo=25554

   (169) https://bugs.python.org/issue?@action=redirect&bpo=18973

   (170) https://bugs.python.org/issue?@action=redirect&bpo=25510

   (171) https://bugs.python.org/issue?@action=redirect&bpo=25503

   (172) https://bugs.python.org/issue?@action=redirect&bpo=25515

   (173) https://bugs.python.org/issue?@action=redirect&bpo=21827

   (174) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (175) https://bugs.python.org/issue?@action=redirect&bpo=25390

   (176) https://bugs.python.org/issue?@action=redirect&bpo=25441

   (177) https://bugs.python.org/issue?@action=redirect&bpo=25410

   (178) https://bugs.python.org/issue?@action=redirect&bpo=25411

   (179) https://bugs.python.org/issue?@action=redirect&bpo=25407

   (180) https://bugs.python.org/issue?@action=redirect&bpo=25406

   (181) https://bugs.python.org/issue?@action=redirect&bpo=25382

   (182) https://bugs.python.org/issue?@action=redirect&bpo=25357

   (183) https://bugs.python.org/issue?@action=redirect&bpo=24164

   (184) https://bugs.python.org/issue?@action=redirect&bpo=25364

   (185) https://bugs.python.org/issue?@action=redirect&bpo=25328

   (186) https://bugs.python.org/issue?@action=redirect&bpo=16099

   (187) https://bugs.python.org/issue?@action=redirect&bpo=25316

   (188) https://bugs.python.org/issue?@action=redirect&bpo=25380

   (189) https://bugs.python.org/issue?@action=redirect&bpo=23972

   (190) https://bugs.python.org/issue?@action=redirect&bpo=25304

   (191) https://bugs.python.org/issue?@action=redirect&bpo=25232

   (192) https://bugs.python.org/issue?@action=redirect&bpo=24657

   (193) https://bugs.python.org/issue?@action=redirect&bpo=25287

   (194) https://bugs.python.org/issue?@action=redirect&bpo=23600

   (195) https://bugs.python.org/issue?@action=redirect&bpo=25203

   (196) https://bugs.python.org/issue?@action=redirect&bpo=25011

   (197) https://bugs.python.org/issue?@action=redirect&bpo=25209

   (198) https://bugs.python.org/issue?@action=redirect&bpo=22241

   (199) https://bugs.python.org/issue?@action=redirect&bpo=23517

   (200) https://bugs.python.org/issue?@action=redirect&bpo=23552

   (201) https://bugs.python.org/issue?@action=redirect&bpo=24633

   (202) https://bugs.python.org/issue?@action=redirect&bpo=24879

   (203) https://bugs.python.org/issue?@action=redirect&bpo=24874

   (204) https://bugs.python.org/issue?@action=redirect&bpo=20059

   (205) https://bugs.python.org/issue?@action=redirect&bpo=24360

   (206) https://bugs.python.org/issue?@action=redirect&bpo=23426

   (207) https://bugs.python.org/issue?@action=redirect&bpo=13938

   (208) https://bugs.python.org/issue?@action=redirect&bpo=2091

   (209) https://bugs.python.org/issue?@action=redirect&bpo=8585

   (210) https://bugs.python.org/issue?@action=redirect&bpo=18622

   (211) https://bugs.python.org/issue?@action=redirect&bpo=24426

   (212) https://bugs.python.org/issue?@action=redirect&bpo=23661

   (213) https://bugs.python.org/issue?@action=redirect&bpo=13248

   (214) https://bugs.python.org/issue?@action=redirect&bpo=25578

   (215) https://bugs.python.org/issue?@action=redirect&bpo=25530

   (216) https://bugs.python.org/issue?@action=redirect&bpo=25569

   (217) https://bugs.python.org/issue?@action=redirect&bpo=25471

   (218) https://bugs.python.org/issue?@action=redirect&bpo=25319

   (219) https://bugs.python.org/issue?@action=redirect&bpo=26050

   (220) https://bugs.python.org/issue?@action=redirect&bpo=25924

   (221) https://bugs.python.org/issue?@action=redirect&bpo=26406

   (222) https://bugs.python.org/issue?@action=redirect&bpo=26848

   (223) https://bugs.python.org/issue?@action=redirect&bpo=27040

   (224) https://bugs.python.org/issue?@action=redirect&bpo=27041


File: python.info,  Node: IDLE<60>,  Next: Documentation<75>,  Prev: Library<165>,  Up: Python 3 6 0 alpha 1

1.23.98.4 IDLE
..............

   - bpo-20640(1): Add tests for idlelib.configHelpSourceEdit.  Patch by
     Saimadhav Heblikar.

   - In the ‘IDLE-console differences’ section of the IDLE doc, clarify
     how running with IDLE affects sys.modules and the standard streams.

   - bpo-25507(2): fix incorrect change in IOBinding that prevented
     printing.  Augment IOBinding htest to include all major IOBinding
     functions.

   - bpo-25905(3): Revert unwanted conversion of ‘ to ’ RIGHT SINGLE
     QUOTATION MARK in README.txt and open this and NEWS.txt with
     ‘ascii’.  Re-encode CREDITS.txt to utf-8 and open it with ‘utf-8’.

   - bpo-15348(4): Stop the debugger engine (normally in a user process)
     before closing the debugger window (running in the IDLE process).
     This prevents the RuntimeErrors that were being caught and ignored.

   - bpo-24455(5): Prevent IDLE from hanging when a) closing the shell
     while the debugger is active (15347); b) closing the debugger with
     the [X] button (15348); and c) activating the debugger when already
     active (24455).  The patch by Mark Roseman does this by making two
     changes.  1.  Suspend and resume the gui.interaction method with
     the tcl vwait mechanism intended for this purpose (instead of
     root.mainloop & .quit).  2.  In gui.run, allow any existing
     interaction to terminate first.

   - Change ‘The program’ to ‘Your program’ in an IDLE ‘kill program?’
     message to make it clearer that the program referred to is the
     currently running user program, not IDLE itself.

   - bpo-24750(6): Improve the appearance of the IDLE editor window
     status bar.  Patch by Mark Roseman.

   - bpo-25313(7): Change the handling of new built-in text color themes
     to better address the compatibility problem introduced by the
     addition of IDLE Dark.  Consistently use the revised
     idleConf.CurrentTheme everywhere in idlelib.

   - bpo-24782(8): Extension configuration is now a tab in the IDLE
     Preferences dialog rather than a separate dialog.  The former tabs
     are now a sorted list.  Patch by Mark Roseman.

   - bpo-22726(9): Re-activate the config dialog help button with some
     content about the other buttons and the new IDLE Dark theme.

   - bpo-24820(10): IDLE now has an ‘IDLE Dark’ built-in text color
     theme.  It is more or less IDLE Classic inverted, with a cobalt
     blue background.  Strings, comments, keywords, … are still green,
     red, orange, … .  To use it with IDLEs released before November
     2015, hit the ‘Save as New Custom Theme’ button and enter a new
     name, such as ‘Custom Dark’.  The custom theme will work with any
     IDLE release, and can be modified.

   - bpo-25224(11): README.txt is now an idlelib index for IDLE
     developers and curious users.  The previous user content is now in
     the IDLE doc chapter.  ‘IDLE’ now means ‘Integrated Development and
     Learning Environment’.

   - bpo-24820(12): Users can now set breakpoint colors in Settings ->
     Custom Highlighting.  Original patch by Mark Roseman.

   - bpo-24972(13): Inactive selection background now matches active
     selection background, as configured by users, on all systems.
     Found items are now always highlighted on Windows.  Initial patch
     by Mark Roseman.

   - bpo-24570(14): Idle: make calltip and completion boxes appear on
     Macs affected by a tk regression.  Initial patch by Mark Roseman.

   - bpo-24988(15): Idle ScrolledList context menus (used in debugger)
     now work on Mac Aqua.  Patch by Mark Roseman.

   - bpo-24801(16): Make right-click for context menu work on Mac Aqua.
     Patch by Mark Roseman.

   - bpo-25173(17): Associate tkinter messageboxes with a specific
     widget.  For Mac OSX, make them a ‘sheet’.  Patch by Mark Roseman.

   - bpo-25198(18): Enhance the initial html viewer now used for Idle
     Help.  Properly indent fixed-pitch text (patch by Mark Roseman).
     Give code snippet a very Sphinx-like light blueish-gray background.
     Re-use initial width and height set by users for shell and editor.
     When the Table of Contents (TOC) menu is used, put the section
     header at the top of the screen.

   - bpo-25225(19): Condense and rewrite Idle doc section on text
     colors.

   - bpo-21995(20): Explain some differences between IDLE and console
     Python.

   - bpo-22820(21): Explain need for 'print' when running file from Idle
     editor.

   - bpo-25224(22): Doc: augment Idle feature list and no-subprocess
     section.

   - bpo-25219(23): Update doc for Idle command line options.  Some were
     missing and notes were not correct.

   - bpo-24861(24): Most of idlelib is private and subject to change.
     Use idleib.idle.* to start Idle.  See idlelib.__init__.__doc__.

   - bpo-25199(25): Idle: add synchronization comments for future
     maintainers.

   - bpo-16893(26): Replace help.txt with help.html for Idle doc
     display.  The new idlelib/help.html is rstripped
     Doc/build/html/library/idle.html.  It looks better than help.txt
     and will better document Idle as released.  The tkinter html viewer
     that works for this file was written by Rose Roseman.  The now
     unused EditorWindow.HelpDialog class and helt.txt file are
     deprecated.

   - bpo-24199(27): Deprecate unused idlelib.idlever with possible
     removal in 3.6.

   - bpo-24790(28): Remove extraneous code (which also create 2 & 3
     conflicts).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20640

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25507

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25905

   (4) https://bugs.python.org/issue?@action=redirect&bpo=15348

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24455

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24750

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25313

   (8) https://bugs.python.org/issue?@action=redirect&bpo=24782

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22726

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24820

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25224

   (12) https://bugs.python.org/issue?@action=redirect&bpo=24820

   (13) https://bugs.python.org/issue?@action=redirect&bpo=24972

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24570

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24988

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24801

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25173

   (18) https://bugs.python.org/issue?@action=redirect&bpo=25198

   (19) https://bugs.python.org/issue?@action=redirect&bpo=25225

   (20) https://bugs.python.org/issue?@action=redirect&bpo=21995

   (21) https://bugs.python.org/issue?@action=redirect&bpo=22820

   (22) https://bugs.python.org/issue?@action=redirect&bpo=25224

   (23) https://bugs.python.org/issue?@action=redirect&bpo=25219

   (24) https://bugs.python.org/issue?@action=redirect&bpo=24861

   (25) https://bugs.python.org/issue?@action=redirect&bpo=25199

   (26) https://bugs.python.org/issue?@action=redirect&bpo=16893

   (27) https://bugs.python.org/issue?@action=redirect&bpo=24199

   (28) https://bugs.python.org/issue?@action=redirect&bpo=24790


File: python.info,  Node: Documentation<75>,  Next: Tests<79>,  Prev: IDLE<60>,  Up: Python 3 6 0 alpha 1

1.23.98.5 Documentation
.......................

   - bpo-26736(1): Used HTTPS for external links in the documentation if
     possible.

   - bpo-6953(2): Rework the Readline module documentation to group
     related functions together, and add more details such as what
     underlying Readline functions and variables are accessed.

   - bpo-23606(3): Adds note to ctypes documentation regarding
     cdll.msvcrt.

   - bpo-24952(4): Clarify the default size argument of stack_size() in
     the “threading” and “_thread” modules.  Patch from Mattip.

   - bpo-26014(5): Update 3.x packaging documentation: * “See also”
     links to the new docs are now provided in the legacy pages * links
     to setuptools documentation have been updated

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26736

   (2) https://bugs.python.org/issue?@action=redirect&bpo=6953

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23606

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24952

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26014


File: python.info,  Node: Tests<79>,  Next: Build<87>,  Prev: Documentation<75>,  Up: Python 3 6 0 alpha 1

1.23.98.6 Tests
...............

   - bpo-21916(1): Added tests for the turtle module.  Patch by ingrid,
     Gregory Loyse and Jelle Zijlstra.

   - bpo-26295(2): When using “python3 -m test –testdir=TESTDIR”,
     regrtest doesn’t add “test.” prefix to test module names.

   - bpo-26523(3): The multiprocessing thread pool
     (multiprocessing.dummy.Pool) was untested.

   - bpo-26015(4): Added new tests for pickling iterators of mutable
     sequences.

   - bpo-26325(5): Added test.support.check_no_resource_warning() to
     check that no ResourceWarning is emitted.

   - bpo-25940(6): Changed test_ssl to use its internal local server
     more.  This avoids relying on svn.python.org, which recently
     changed root certificate.

   - bpo-25616(7): Tests for OrderedDict are extracted from
     test_collections into separate file test_ordered_dict.

   - bpo-25449(8): Added tests for OrderedDict subclasses.

   - bpo-25188(9): Add -P/–pgo to test.regrtest to suppress error output
     when running the test suite for the purposes of a PGO build.
     Initial patch by Alecsandru Patrascu.

   - bpo-22806(10): Add ‘python -m test --list-tests’ command to list
     tests.

   - bpo-18174(11): ‘python -m test --huntrleaks ...’ now also checks
     for leak of file descriptors.  Patch written by Richard Oudkerk.

   - bpo-25260(12): Fix ‘python -m test --coverage’ on Windows.  Remove
     the list of ignored directories.

   - ‘PCbuild\rt.bat’ now accepts an unlimited number of arguments to
     pass along to regrtest.py.  Previously there was a limit of 9.

   - bpo-26583(13): Skip test_timestamp_overflow in test_import if
     bytecode files cannot be written.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21916

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26295

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26523

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26015

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26325

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25940

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25616

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25449

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25188

   (10) https://bugs.python.org/issue?@action=redirect&bpo=22806

   (11) https://bugs.python.org/issue?@action=redirect&bpo=18174

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25260

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26583


File: python.info,  Node: Build<87>,  Next: Windows<74>,  Prev: Tests<79>,  Up: Python 3 6 0 alpha 1

1.23.98.7 Build
...............

   - bpo-21277(1): Don’t try to link _ctypes with a ffi_convenience
     library.

   - bpo-26884(2): Fix linking extension modules for cross builds.
     Patch by Xavier de Gaye.

   - bpo-26932(3): Fixed support of RTLD_* constants defined as enum
     values, not via macros (in particular on Android).  Patch by Chi
     Hsuan Yen.

   - bpo-22359(4): Disable the rules for running _freeze_importlib and
     pgen when cross-compiling.  The output of these programs is
     normally saved with the source code anyway, and is still
     regenerated when doing a native build.  Patch by Xavier de Gaye.

   - bpo-21668(5): Link audioop, _datetime, _ctypes_test modules to
     libm, except on Mac OS X. Patch written by Chi Hsuan Yen.

   - bpo-25702(6): A –with-lto configure option has been added that will
     enable link time optimizations at build time during a make
     profile-opt.  Some compilers and toolchains are known to not
     produce stable code when using LTO, be sure to test things
     thoroughly before relying on it.  It can provide a few % speed up
     over profile-opt alone.

   - bpo-26624(7): Adds validation of ucrtbase[d].dll version with
     warning for old versions.

   - bpo-17603(8): Avoid error about nonexistent fileblocks.o file by
     using a lower-level check for st_blocks in struct stat.

   - bpo-26079(9): Fixing the build output folder for tix-8.4.3.6.
     Patch by Bjoern Thiel.

   - bpo-26465(10): Update Windows builds to use OpenSSL 1.0.2g.

   - bpo-25348(11): Added ‘--pgo’ and ‘--pgo-job’ arguments to
     ‘PCbuild\build.bat’ for building with Profile-Guided Optimization.
     The old ‘PCbuild\build_pgo.bat’ script is removed.

   - bpo-25827(12): Add support for building with ICC to ‘configure’,
     including a new ‘--with-icc’ flag.

   - bpo-25696(13): Fix installation of Python on UNIX with make -j9.

   - bpo-24986(14): It is now possible to build Python on Windows
     without errors when external libraries are not available.

   - bpo-24421(15): Compile Modules/_math.c once, before building
     extensions.  Previously it could fail to compile properly if the
     math and cmath builds were concurrent.

   - bpo-26465(16): Update OS X 10.5+ 32-bit-only installer to build and
     link with OpenSSL 1.0.2g.

   - bpo-26268(17): Update Windows builds to use OpenSSL 1.0.2f.

   - bpo-25136(18): Support Apple Xcode 7’s new textual SDK stub
     libraries.

   - bpo-24324(19): Do not enable unreachable code warnings when using
     gcc as the option does not work correctly in older versions of gcc
     and has been silently removed as of gcc-4.5.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21277

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26884

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26932

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22359

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21668

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25702

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26624

   (8) https://bugs.python.org/issue?@action=redirect&bpo=17603

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26079

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26465

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25348

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25827

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25696

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24986

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24421

   (16) https://bugs.python.org/issue?@action=redirect&bpo=26465

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26268

   (18) https://bugs.python.org/issue?@action=redirect&bpo=25136

   (19) https://bugs.python.org/issue?@action=redirect&bpo=24324


File: python.info,  Node: Windows<74>,  Next: Tools/Demos<47>,  Prev: Build<87>,  Up: Python 3 6 0 alpha 1

1.23.98.8 Windows
.................

   - bpo-27053(1): Updates make_zip.py to correctly generate library ZIP
     file.

   - bpo-26268(2): Update the prepare_ssl.py script to handle OpenSSL
     releases that don’t include the contents of the include directory
     (that is, 1.0.2e and later).

   - bpo-26071(3): bdist_wininst created binaries fail to start and find
     32bit Python

   - bpo-26073(4): Update the list of magic numbers in launcher

   - bpo-26065(5): Excludes venv from library when generating embeddable
     distro.

   - bpo-25022(6): Removed very outdated PC/example_nt/ directory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27053

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26268

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26071

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26073

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26065

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25022


File: python.info,  Node: Tools/Demos<47>,  Next: C API<73>,  Prev: Windows<74>,  Up: Python 3 6 0 alpha 1

1.23.98.9 Tools/Demos
.....................

   - bpo-26799(1): Fix python-gdb.py: don’t get C types once when the
     Python code is loaded, but get C types on demand.  The C types can
     change if python-gdb.py is loaded before the Python executable.
     Patch written by Thomas Ilsche.

   - bpo-26271(2): Fix the Freeze tool to properly use flags passed
     through configure.  Patch by Daniel Shaulov.

   - bpo-26489(3): Add dictionary unpacking support to
     Tools/parser/unparse.py.  Patch by Guo Ci Teo.

   - bpo-26316(4): Fix variable name typo in Argument Clinic.

   - bpo-25440(5): Fix output of python-config –extension-suffix.

   - bpo-25154(6): The pyvenv script has been deprecated in favour of
     ‘python3 -m venv’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26799

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26271

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26489

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26316

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25440

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25154


File: python.info,  Node: C API<73>,  Prev: Tools/Demos<47>,  Up: Python 3 6 0 alpha 1

1.23.98.10 C API
................

   - bpo-26312(1): SystemError is now raised in all programming bugs
     with using PyArg_ParseTupleAndKeywords().  RuntimeError did raised
     before in some programming bugs.

   - bpo-26198(2): ValueError is now raised instead of TypeError on
     buffer overflow in parsing “es#” and “et#” format units.
     SystemError is now raised instead of TypeError on programmatical
     error in parsing format string.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26312

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26198


File: python.info,  Node: Python 3 5 5 final,  Next: Python 3 5 5 release candidate 1,  Prev: Python 3 6 0 alpha 1,  Up: Changelog

1.23.99 Python 3.5.5 final
--------------------------

'Release date: 2018-02-04'

There were no new changes in version 3.5.5.


File: python.info,  Node: Python 3 5 5 release candidate 1,  Next: Python 3 5 4 final,  Prev: Python 3 5 5 final,  Up: Changelog

1.23.100 Python 3.5.5 release candidate 1
-----------------------------------------

'Release date: 2018-01-23'

* Menu:

* Security: Security<54>.
* Core and Builtins: Core and Builtins<164>.
* Library: Library<166>.


File: python.info,  Node: Security<54>,  Next: Core and Builtins<164>,  Up: Python 3 5 5 release candidate 1

1.23.100.1 Security
...................

   - bpo-32551(1): The ‘sys.path[0]’ initialization change for
     bpo-29139(2) caused a regression by revealing an inconsistency in
     how sys.path is initialized when executing ‘__main__’ from a
     zipfile, directory, or other import location.  This is considered a
     potential security issue, as it may lead to privileged processes
     unexpectedly loading code from user controlled directories in
     situations where that was not previously the case.  The interpreter
     now consistently avoids ever adding the import location’s parent
     directory to ‘sys.path’, and ensures no other ‘sys.path’ entries
     are inadvertently modified when inserting the import location named
     on the command line.  (Originally reported as bpo-29723(3) against
     Python 3.6rc1, but it was missed at the time that the then upcoming
     Python 3.5.4 release would also be affected)

   - bpo-30657(4): Fixed possible integer overflow in
     PyBytes_DecodeEscape, CVE 2017-1000158(5).  Original patch by Jay
     Bosamiya; rebased to Python 3 by Miro Hrončok.

   - bpo-30947(6): Upgrade libexpat embedded copy from version 2.2.1 to
     2.2.3 to get security fixes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32551

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29139

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29723

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30657

   (5) https://www.cve.org/CVERecord?id=CVE-2017-1000158

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30947


File: python.info,  Node: Core and Builtins<164>,  Next: Library<166>,  Prev: Security<54>,  Up: Python 3 5 5 release candidate 1

1.23.100.2 Core and Builtins
............................

   - bpo-31095(1): Fix potential crash during GC caused by ‘tp_dealloc’
     which doesn’t call ‘PyObject_GC_UnTrack()’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=31095


File: python.info,  Node: Library<166>,  Prev: Core and Builtins<164>,  Up: Python 3 5 5 release candidate 1

1.23.100.3 Library
..................

   - bpo-32072(1): Fixed issues with binary plists: Fixed saving
     bytearrays.  Identical objects will be saved only once.  Equal
     references will be load as identical objects.  Added support for
     saving and loading recursive data structures.

   - bpo-31170(2): expat: Update libexpat from 2.2.3 to 2.2.4.  Fix
     copying of partial characters for UTF-8 input (libexpat bug 115):
     ‘https://github.com/libexpat/libexpat/issues/115’

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=32072

   (2) https://bugs.python.org/issue?@action=redirect&bpo=31170


File: python.info,  Node: Python 3 5 4 final,  Next: Python 3 5 4 release candidate 1,  Prev: Python 3 5 5 release candidate 1,  Up: Changelog

1.23.101 Python 3.5.4 final
---------------------------

'Release date: 2017-08-07'

* Menu:

* Library: Library<167>.


File: python.info,  Node: Library<167>,  Up: Python 3 5 4 final

1.23.101.1 Library
..................

   - bpo-30119(1): ftplib.FTP.putline() now throws ValueError on
     commands that contains CR or LF. Patch by Donghee Na.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30119


File: python.info,  Node: Python 3 5 4 release candidate 1,  Next: Python 3 5 3 final,  Prev: Python 3 5 4 final,  Up: Changelog

1.23.102 Python 3.5.4 release candidate 1
-----------------------------------------

'Release date: 2017-07-23'

* Menu:

* Security: Security<55>.
* Core and Builtins: Core and Builtins<165>.
* Library: Library<168>.
* Documentation: Documentation<76>.
* Tests: Tests<80>.
* Build: Build<88>.
* Windows: Windows<75>.
* C API: C API<74>.


File: python.info,  Node: Security<55>,  Next: Core and Builtins<165>,  Up: Python 3 5 4 release candidate 1

1.23.102.1 Security
...................

   - bpo-30730(1): Prevent environment variables injection in subprocess
     on Windows.  Prevent passing other environment variables and
     command arguments.

   - bpo-30694(2): Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes
     of multiple security vulnerabilities including: CVE 2017-9233(3)
     (External entity infinite loop DoS), CVE 2016-9063(4) (Integer
     overflow, re-fix), CVE 2016-0718(5) (Fix regression bugs from
     2.2.0’s fix to CVE 2016-0718(6)) and CVE 2012-0876(7) (Counter hash
     flooding with SipHash).  Note: the CVE 2016-5300(8) (Use
     os-specific entropy sources like getrandom) doesn’t impact Python,
     since Python already gets entropy from the OS to set the expat
     secret using ‘XML_SetHashSalt()’.

   - bpo-30500(9): Fix urllib.parse.splithost() to correctly parse
     fragments.  For example, ‘splithost('//127.0.0.1#@evil.com/')’ now
     correctly returns the ‘127.0.0.1’ host, instead of treating
     ‘@evil.com’ as the host in an authentication (‘login@host’).

   - bpo-29591(10): Update expat copy from 2.1.1 to 2.2.0 to get fixes
     of CVE 2016-0718(11) and CVE 2016-4472(12).  See
     ‘https://sourceforge.net/p/expat/bugs/537/’ for more information.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30730

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30694

   (3) https://www.cve.org/CVERecord?id=CVE-2017-9233

   (4) https://www.cve.org/CVERecord?id=CVE-2016-9063

   (5) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (6) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (7) https://www.cve.org/CVERecord?id=CVE-2012-0876

   (8) https://www.cve.org/CVERecord?id=CVE-2016-5300

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30500

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29591

   (11) https://www.cve.org/CVERecord?id=CVE-2016-0718

   (12) https://www.cve.org/CVERecord?id=CVE-2016-4472


File: python.info,  Node: Core and Builtins<165>,  Next: Library<168>,  Prev: Security<55>,  Up: Python 3 5 4 release candidate 1

1.23.102.2 Core and Builtins
............................

   - bpo-30876(1): Relative import from unloaded package now reimports
     the package instead of failing with SystemError.  Relative import
     from non-package now fails with ImportError rather than
     SystemError.

   - bpo-30765(2): Avoid blocking in pthread_mutex_lock() when
     PyThread_acquire_lock() is asked not to block.

   - bpo-27945(3): Fixed various segfaults with dict when input
     collections are mutated during searching, inserting or comparing.
     Based on patches by Duane Griffin and Tim Mitchell.

   - bpo-25794(4): Fixed type.__setattr__() and type.__delattr__() for
     non-interned attribute names.  Based on patch by Eryk Sun.

   - bpo-29935(5): Fixed error messages in the index() method of tuple,
     list and deque when pass indices of wrong type.

   - bpo-28876(6): ‘bool(range)’ works even if ‘len(range)’ raises *note
     OverflowError: 888.

   - bpo-29600(7): Fix wrapping coroutine return values in
     StopIteration.

   - bpo-29537(8): Restore runtime compatibility with bytecode files
     generated by CPython 3.5.0 to 3.5.2, and adjust the eval loop to
     avoid the problems that could be caused by the malformed variant of
     the BUILD_MAP_UNPACK_WITH_CALL opcode that they may contain.  Patch
     by Petr Viktorin, Serhiy Storchaka, and Nick Coghlan.

   - bpo-28598(9): Support __rmod__ for subclasses of str being called
     before str.__mod__.  Patch by Martijn Pieters.

   - bpo-29602(10): Fix incorrect handling of signed zeros in complex
     constructor for complex subclasses and for inputs having a
     __complex__ method.  Patch by Serhiy Storchaka.

   - bpo-29347(11): Fixed possibly dereferencing undefined pointers when
     creating weakref objects.

   - bpo-29438(12): Fixed use-after-free problem in key sharing dict.

   - bpo-29319(13): Prevent RunMainFromImporter overwriting sys.path[0].

   - bpo-29337(14): Fixed possible BytesWarning when compare the code
     objects.  Warnings could be emitted at compile time.

   - bpo-29478(15): If max_line_length=None is specified while using the
     Compat32 policy, it is no longer ignored.  Patch by Mircea Cosbuc.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30876

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30765

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27945

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25794

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29935

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28876

   (7) https://bugs.python.org/issue?@action=redirect&bpo=29600

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29537

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28598

   (10) https://bugs.python.org/issue?@action=redirect&bpo=29602

   (11) https://bugs.python.org/issue?@action=redirect&bpo=29347

   (12) https://bugs.python.org/issue?@action=redirect&bpo=29438

   (13) https://bugs.python.org/issue?@action=redirect&bpo=29319

   (14) https://bugs.python.org/issue?@action=redirect&bpo=29337

   (15) https://bugs.python.org/issue?@action=redirect&bpo=29478


File: python.info,  Node: Library<168>,  Next: Documentation<76>,  Prev: Core and Builtins<165>,  Up: Python 3 5 4 release candidate 1

1.23.102.3 Library
..................

   - bpo-29403(1): Fix ‘unittest.mock’’s autospec to not fail on
     method-bound builtin functions.  Patch by Aaron Gallagher.

   - bpo-30961(2): Fix decrementing a borrowed reference in tracemalloc.

   - bpo-30886(3): Fix multiprocessing.Queue.join_thread(): it now waits
     until the thread completes, even if the thread was started by the
     same process which created the queue.

   - bpo-29854(4): Fix segfault in readline when using readline’s
     history-size option.  Patch by Nir Soffer.

   - bpo-30807(5): signal.setitimer() may disable the timer when passed
     a tiny value.  Tiny values (such as 1e-6) are valid non-zero values
     for setitimer(), which is specified as taking
     microsecond-resolution intervals.  However, on some platform, our
     conversion routine could convert 1e-6 into a zero interval,
     therefore disabling the timer instead of (re-)scheduling it.

   - bpo-30441(6): Fix bug when modifying os.environ while iterating
     over it

   - bpo-30532(7): Fix email header value parser dropping folding white
     space in certain cases.

   - bpo-29169(8): Update zlib to 1.2.11.

   - bpo-30879(9): os.listdir() and os.scandir() now emit bytes names
     when called with bytes-like argument.

   - bpo-30746(10): Prohibited the ‘=’ character in environment variable
     names in ‘os.putenv()’ and ‘os.spawn*()’.

   - bpo-29755(11): Fixed the lgettext() family of functions in the
     gettext module.  They now always return bytes.

   - bpo-30645(12): Fix path calculation in imp.load_package(), fixing
     it for cases when a package is only shipped with bytecodes.  Patch
     by Alexandru Ardelean.

   - bpo-23890(13): unittest.TestCase.assertRaises() now manually breaks
     a reference cycle to not keep objects alive longer than expected.

   - bpo-30149(14): inspect.signature() now supports callables with
     variable-argument parameters wrapped with partialmethod.  Patch by
     Donghee Na.

   - bpo-29931(15): Fixed comparison check for ipaddress.ip_interface
     objects.  Patch by Sanjay Sundaresan.

   - bpo-24484(16): Avoid race condition in multiprocessing cleanup.

   - bpo-28994(17): The traceback no longer displayed for SystemExit
     raised in a callback registered by atexit.

   - bpo-30508(18): Don’t log exceptions if Task/Future “cancel()”
     method was called.

   - bpo-28556(19): Updates to typing module: Add generic
     AsyncContextManager, add support for ContextManager on all
     versions.  Original PRs by Jelle Zijlstra and Ivan Levkivskyi

   - bpo-29870(20): Fix ssl sockets leaks when connection is aborted in
     asyncio/ssl implementation.  Patch by Michaël Sghaïer.

   - bpo-29743(21): Closing transport during handshake process leaks
     open socket.  Patch by Nikolay Kim

   - bpo-27585(22): Fix waiter cancellation in asyncio.Lock.  Patch by
     Mathieu Sornay.

   - bpo-30418(23): On Windows, subprocess.Popen.communicate() now also
     ignore EINVAL on stdin.write() if the child process is still
     running but closed the pipe.

   - bpo-30378(24): Fix the problem that logging.handlers.SysLogHandler
     cannot handle IPv6 addresses.

   - bpo-29960(25): Preserve generator state when
     _random.Random.setstate() raises an exception.  Patch by Bryan
     Olson.

   - bpo-30414(26): multiprocessing.Queue._feed background running
     thread do not break from main loop on exception.

   - bpo-30003(27): Fix handling escape characters in HZ codec.  Based
     on patch by Ma Lin.

   - bpo-30301(28): Fix AttributeError when using SimpleQueue.empty()
     under 'spawn' and 'forkserver' start methods.

   - bpo-30329(29): imaplib and poplib now catch the Windows socket
     WSAEINVAL error (code 10022) on shutdown(SHUT_RDWR): An invalid
     operation was attempted.  This error occurs sometimes on SSL
     connections.

   - bpo-30375(30): Warnings emitted when compile a regular expression
     now always point to the line in the user code.  Previously they
     could point into inners of the re module if emitted from inside of
     groups or conditionals.

   - bpo-30048(31): Fixed ‘Task.cancel()’ can be ignored when the task
     is running coroutine and the coroutine returned without any more
     ‘await’.

   - bpo-29990(32): Fix range checking in GB18030 decoder.  Original
     patch by Ma Lin.

   - bpo-26293(33): Change resulted because of zipfile breakage.  (See
     also: bpo-29094(34))

   - bpo-30243(35): Removed the __init__ methods of _json’s scanner and
     encoder.  Misusing them could cause memory leaks or crashes.  Now
     scanner and encoder objects are completely initialized in the
     __new__ methods.

   - bpo-30185(36): Avoid KeyboardInterrupt tracebacks in forkserver
     helper process when Ctrl-C is received.

   - bpo-28556(37): Various updates to typing module: add
     typing.NoReturn type, use WrapperDescriptorType, minor bug-fixes.
     Original PRs by Jim Fasarakis-Hilliard and Ivan Levkivskyi.

   - bpo-30205(38): Fix getsockname() for unbound AF_UNIX sockets on
     Linux.

   - bpo-30070(39): Fixed leaks and crashes in errors handling in the
     parser module.

   - bpo-30061(40): Fixed crashes in IOBase methods __next__() and
     readlines() when readline() or __next__() respectively return
     non-sizeable object.  Fixed possible other errors caused by not
     checking results of PyObject_Size(), PySequence_Size(), or
     PyMapping_Size().

   - bpo-30068(41): _io._IOBase.readlines will check if it’s closed
     first when hint is present.

   - bpo-29694(42): Fixed race condition in pathlib mkdir with flags
     parents=True.  Patch by Armin Rigo.

   - bpo-29692(43): Fixed arbitrary unchaining of RuntimeError
     exceptions in contextlib.contextmanager.  Patch by Siddharth
     Velankar.

   - bpo-29998(44): Pickling and copying ImportError now preserves name
     and path attributes.

   - bpo-29942(45): Fix a crash in itertools.chain.from_iterable when
     encountering long runs of empty iterables.

   - bpo-27863(46): Fixed multiple crashes in ElementTree caused by race
     conditions and wrong types.

   - bpo-28699(47): Fixed a bug in pools in multiprocessing.pool that
     raising an exception at the very first of an iterable may swallow
     the exception or make the program hang.  Patch by Davin Potts and
     Xiang Zhang.

   - bpo-25803(48): Avoid incorrect errors raised by
     Path.mkdir(exist_ok=True) when the OS gives priority to errors such
     as EACCES over EEXIST.

   - bpo-29861(49): Release references to tasks, their arguments and
     their results as soon as they are finished in multiprocessing.Pool.

   - bpo-29884(50): faulthandler: Restore the old sigaltstack during
     teardown.  Patch by Christophe Zeitouny.

   - bpo-25455(51): Fixed crashes in repr of recursive buffered
     file-like objects.

   - bpo-29800(52): Fix crashes in partial.__repr__ if the keys of
     partial.keywords are not strings.  Patch by Michael Seifert.

   - bpo-29742(53): get_extra_info() raises exception if get called on
     closed ssl transport.  Patch by Nikolay Kim.

   - bpo-8256(54): Fixed possible failing or crashing input() if
     attributes “encoding” or “errors” of sys.stdin or sys.stdout are
     not set or are not strings.

   - bpo-28298(55): Fix a bug that prevented array ‘Q’, ‘L’ and ‘I’ from
     accepting big intables (objects that have __int__) as elements.
     Patch by Oren Milman.

   - bpo-29615(56): SimpleXMLRPCDispatcher no longer chains KeyError (or
     any other exception) to exception(s) raised in the dispatched
     methods.  Patch by Petr Motejlek.

   - bpo-29704(57): asyncio.subprocess.SubprocessStreamProtocol no
     longer closes before all pipes are closed.

   - bpo-29703(58): Fix asyncio to support instantiation of new event
     loops in child processes.

   - bpo-29376(59): Fix assertion error in
     threading._DummyThread.is_alive().

   - bpo-29110(60): Fix file object leak in aifc.open() when file is
     given as a filesystem path and is not in valid AIFF format.  Patch
     by Anthony Zhang.

   - bpo-28961(61): Fix unittest.mock._Call helper: don’t ignore the
     name parameter anymore.  Patch written by Jiajun Huang.

   - bpo-29532(62): Altering a kwarg dictionary passed to
     functools.partial() no longer affects a partial object after
     creation.

   - bpo-28556(63): Various updates to typing module: typing.Counter,
     typing.ChainMap, improved ABC caching, etc.  Original PRs by Jelle
     Zijlstra, Ivan Levkivskyi, Manuel Krebber, and Łukasz Langa.

   - bpo-29100(64): Fix datetime.fromtimestamp() regression introduced
     in Python 3.6.0: check minimum and maximum years.

   - bpo-29519(65): Fix weakref spewing exceptions during interpreter
     shutdown when used with a rare combination of multiprocessing and
     custom codecs.

   - bpo-29416(66): Prevent infinite loop in pathlib.Path.mkdir

   - bpo-29444(67): Fixed out-of-bounds buffer access in the group()
     method of the match object.  Based on patch by WGH.

   - bpo-29335(68): Fix subprocess.Popen.wait() when the child process
     has exited to a stopped instead of terminated state (ex: when under
     ptrace).

   - bpo-29290(69): Fix a regression in argparse that help messages
     would wrap at non-breaking spaces.

   - bpo-28735(70): Fixed the comparison of mock.MagickMock with
     mock.ANY.

   - bpo-29011(71): Fix an important omission by adding Deque to the
     typing module.

   - bpo-29219(72): Fixed infinite recursion in the repr of
     uninitialized ctypes.CDLL instances.

   - bpo-28969(73): Fixed race condition in C implementation of
     functools.lru_cache.  KeyError could be raised when cached function
     with full cache was simultaneously called from different threads
     with the same uncached arguments.

   - bpo-29142(74): In urllib.request, suffixes in no_proxy environment
     variable with leading dots could match related hostnames again
     (e.g.  .b.c matches a.b.c).  Patch by Milan Oberkirch.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29403

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30961

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30886

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29854

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30807

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30441

   (7) https://bugs.python.org/issue?@action=redirect&bpo=30532

   (8) https://bugs.python.org/issue?@action=redirect&bpo=29169

   (9) https://bugs.python.org/issue?@action=redirect&bpo=30879

   (10) https://bugs.python.org/issue?@action=redirect&bpo=30746

   (11) https://bugs.python.org/issue?@action=redirect&bpo=29755

   (12) https://bugs.python.org/issue?@action=redirect&bpo=30645

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23890

   (14) https://bugs.python.org/issue?@action=redirect&bpo=30149

   (15) https://bugs.python.org/issue?@action=redirect&bpo=29931

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24484

   (17) https://bugs.python.org/issue?@action=redirect&bpo=28994

   (18) https://bugs.python.org/issue?@action=redirect&bpo=30508

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (20) https://bugs.python.org/issue?@action=redirect&bpo=29870

   (21) https://bugs.python.org/issue?@action=redirect&bpo=29743

   (22) https://bugs.python.org/issue?@action=redirect&bpo=27585

   (23) https://bugs.python.org/issue?@action=redirect&bpo=30418

   (24) https://bugs.python.org/issue?@action=redirect&bpo=30378

   (25) https://bugs.python.org/issue?@action=redirect&bpo=29960

   (26) https://bugs.python.org/issue?@action=redirect&bpo=30414

   (27) https://bugs.python.org/issue?@action=redirect&bpo=30003

   (28) https://bugs.python.org/issue?@action=redirect&bpo=30301

   (29) https://bugs.python.org/issue?@action=redirect&bpo=30329

   (30) https://bugs.python.org/issue?@action=redirect&bpo=30375

   (31) https://bugs.python.org/issue?@action=redirect&bpo=30048

   (32) https://bugs.python.org/issue?@action=redirect&bpo=29990

   (33) https://bugs.python.org/issue?@action=redirect&bpo=26293

   (34) https://bugs.python.org/issue?@action=redirect&bpo=29094

   (35) https://bugs.python.org/issue?@action=redirect&bpo=30243

   (36) https://bugs.python.org/issue?@action=redirect&bpo=30185

   (37) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (38) https://bugs.python.org/issue?@action=redirect&bpo=30205

   (39) https://bugs.python.org/issue?@action=redirect&bpo=30070

   (40) https://bugs.python.org/issue?@action=redirect&bpo=30061

   (41) https://bugs.python.org/issue?@action=redirect&bpo=30068

   (42) https://bugs.python.org/issue?@action=redirect&bpo=29694

   (43) https://bugs.python.org/issue?@action=redirect&bpo=29692

   (44) https://bugs.python.org/issue?@action=redirect&bpo=29998

   (45) https://bugs.python.org/issue?@action=redirect&bpo=29942

   (46) https://bugs.python.org/issue?@action=redirect&bpo=27863

   (47) https://bugs.python.org/issue?@action=redirect&bpo=28699

   (48) https://bugs.python.org/issue?@action=redirect&bpo=25803

   (49) https://bugs.python.org/issue?@action=redirect&bpo=29861

   (50) https://bugs.python.org/issue?@action=redirect&bpo=29884

   (51) https://bugs.python.org/issue?@action=redirect&bpo=25455

   (52) https://bugs.python.org/issue?@action=redirect&bpo=29800

   (53) https://bugs.python.org/issue?@action=redirect&bpo=29742

   (54) https://bugs.python.org/issue?@action=redirect&bpo=8256

   (55) https://bugs.python.org/issue?@action=redirect&bpo=28298

   (56) https://bugs.python.org/issue?@action=redirect&bpo=29615

   (57) https://bugs.python.org/issue?@action=redirect&bpo=29704

   (58) https://bugs.python.org/issue?@action=redirect&bpo=29703

   (59) https://bugs.python.org/issue?@action=redirect&bpo=29376

   (60) https://bugs.python.org/issue?@action=redirect&bpo=29110

   (61) https://bugs.python.org/issue?@action=redirect&bpo=28961

   (62) https://bugs.python.org/issue?@action=redirect&bpo=29532

   (63) https://bugs.python.org/issue?@action=redirect&bpo=28556

   (64) https://bugs.python.org/issue?@action=redirect&bpo=29100

   (65) https://bugs.python.org/issue?@action=redirect&bpo=29519

   (66) https://bugs.python.org/issue?@action=redirect&bpo=29416

   (67) https://bugs.python.org/issue?@action=redirect&bpo=29444

   (68) https://bugs.python.org/issue?@action=redirect&bpo=29335

   (69) https://bugs.python.org/issue?@action=redirect&bpo=29290

   (70) https://bugs.python.org/issue?@action=redirect&bpo=28735

   (71) https://bugs.python.org/issue?@action=redirect&bpo=29011

   (72) https://bugs.python.org/issue?@action=redirect&bpo=29219

   (73) https://bugs.python.org/issue?@action=redirect&bpo=28969

   (74) https://bugs.python.org/issue?@action=redirect&bpo=29142


File: python.info,  Node: Documentation<76>,  Next: Tests<80>,  Prev: Library<168>,  Up: Python 3 5 4 release candidate 1

1.23.102.4 Documentation
........................

   - bpo-30176(1): Add missing attribute related constants in curses
     documentation.

   - bpo-26985(2): Add missing info of code object in inspect
     documentation.

   - bpo-28929(3): Link the documentation to its source file on GitHub.

   - bpo-25008(4): Document smtpd.py as effectively deprecated and add a
     pointer to aiosmtpd, a third-party asyncio-based replacement.

   - bpo-26355(5): Add canonical header link on each page to
     corresponding major version of the documentation.  Patch by
     Matthias Bussonnier.

   - bpo-29349(6): Fix Python 2 syntax in code for building the
     documentation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30176

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26985

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28929

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25008

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26355

   (6) https://bugs.python.org/issue?@action=redirect&bpo=29349


File: python.info,  Node: Tests<80>,  Next: Build<88>,  Prev: Documentation<76>,  Up: Python 3 5 4 release candidate 1

1.23.102.5 Tests
................

   - bpo-30822(1): Fix regrtest command line parser to allow passing -u
     extralargefile to run test_zipfile64.

   - bpo-30383(2): regrtest: Enhance regrtest and backport features from
     the master branch.  Add options: –coverage, –testdir, –list-tests
     (list test files, don’t run them), –list-cases (list test
     identifiers, don’t run them, bpo-30523(3)), –matchfile (load a list
     of test filters from a text file, bpo-30540(4)), –slowest (alias to
     –slow).  Enhance output: add timestamp, test result, currently
     running tests, “Tests result: xxx” summary with total duration,
     etc.  Fix reference leak hunting in regrtest, –huntrleaks: regrtest
     now warms up caches, create explicitly all internal singletons
     which are created on demand to prevent false positives when
     checking for reference leaks.  (bpo-30675(5)).

   - bpo-30357(6): test_thread: setUp() now uses
     support.threading_setup() and support.threading_cleanup() to wait
     until threads complete to avoid random side effects on following
     tests.  Initial patch written by Grzegorz Grzywacz.

   - bpo-28087(7): Skip test_asyncore and test_eintr poll failures on
     macOS. Skip some tests of select.poll when running on macOS due to
     unresolved issues with the underlying system poll function on some
     macOS versions.

   - bpo-30197(8): Enhanced functions swap_attr() and swap_item() in the
     test.support module.  They now work when delete replaced attribute
     or item inside the with statement.  The old value of the attribute
     or item (or None if it doesn’t exist) now will be assigned to the
     target of the “as” clause, if there is one.

   - bpo-29571(9): to match the behaviour of the ‘re.LOCALE’ flag,
     test_re.test_locale_flag now uses
     ‘locale.getpreferredencoding(False)’ to determine the candidate
     encoding for the test regex (allowing it to correctly skip the test
     when the default locale encoding is a multi-byte encoding)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30822

   (2) https://bugs.python.org/issue?@action=redirect&bpo=30383

   (3) https://bugs.python.org/issue?@action=redirect&bpo=30523

   (4) https://bugs.python.org/issue?@action=redirect&bpo=30540

   (5) https://bugs.python.org/issue?@action=redirect&bpo=30675

   (6) https://bugs.python.org/issue?@action=redirect&bpo=30357

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28087

   (8) https://bugs.python.org/issue?@action=redirect&bpo=30197

   (9) https://bugs.python.org/issue?@action=redirect&bpo=29571


File: python.info,  Node: Build<88>,  Next: Windows<75>,  Prev: Tests<80>,  Up: Python 3 5 4 release candidate 1

1.23.102.6 Build
................

   - bpo-29243(1): Prevent unnecessary rebuilding of Python during ‘make
     test’, ‘make install’ and some other make targets when configured
     with ‘--enable-optimizations’.

   - bpo-23404(2): Don’t regenerate generated files based on file
     modification time anymore: the action is now explicit.  Replace
     ‘make touch’ with ‘make regen-all’.

   - bpo-29643(3): Fix ‘--enable-optimization’ didn’t work.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29243

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23404

   (3) https://bugs.python.org/issue?@action=redirect&bpo=29643


File: python.info,  Node: Windows<75>,  Next: C API<74>,  Prev: Build<88>,  Up: Python 3 5 4 release candidate 1

1.23.102.7 Windows
..................

   - bpo-30687(1): Locate msbuild.exe on Windows when building rather
     than vcvarsall.bat

   - bpo-29392(2): Prevent crash when passing invalid arguments into
     msvcrt module.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=30687

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29392


File: python.info,  Node: C API<74>,  Prev: Windows<75>,  Up: Python 3 5 4 release candidate 1

1.23.102.8 C API
................

   - bpo-27867(1): Function PySlice_GetIndicesEx() is replaced with a
     macro if Py_LIMITED_API is set to the value between 0x03050400 and
     0x03060000 (not including) or 0x03060100 or higher.

   - bpo-29083(2): Fixed the declaration of some public API functions.
     PyArg_VaParse() and PyArg_VaParseTupleAndKeywords() were not
     available in limited API. PyArg_ValidateKeywordArguments(),
     PyArg_UnpackTuple() and Py_BuildValue() were not available in
     limited API of version < 3.3 when PY_SSIZE_T_CLEAN is defined.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27867

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29083


File: python.info,  Node: Python 3 5 3 final,  Next: Python 3 5 3 release candidate 1,  Prev: Python 3 5 4 release candidate 1,  Up: Changelog

1.23.103 Python 3.5.3 final
---------------------------

'Release date: 2017-01-17'

There were no code changes between 3.5.3rc1 and 3.5.3 final.


File: python.info,  Node: Python 3 5 3 release candidate 1,  Next: Python 3 5 2 final,  Prev: Python 3 5 3 final,  Up: Changelog

1.23.104 Python 3.5.3 release candidate 1
-----------------------------------------

'Release date: 2017-01-02'

* Menu:

* Security: Security<56>.
* Core and Builtins: Core and Builtins<166>.
* Library: Library<169>.
* IDLE: IDLE<61>.
* C API: C API<75>.
* Documentation: Documentation<77>.
* Tests: Tests<81>.
* Tools/Demos: Tools/Demos<48>.
* Windows: Windows<76>.
* Build: Build<89>.


File: python.info,  Node: Security<56>,  Next: Core and Builtins<166>,  Up: Python 3 5 3 release candidate 1

1.23.104.1 Security
...................

   - bpo-27278(1): Fix os.urandom() implementation using getrandom() on
     Linux.  Truncate size to INT_MAX and loop until we collected enough
     random bytes, instead of casting a directly Py_ssize_t to int.

   - bpo-22636(2): Avoid shell injection problems with
     ctypes.util.find_library().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27278

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22636


File: python.info,  Node: Core and Builtins<166>,  Next: Library<169>,  Prev: Security<56>,  Up: Python 3 5 3 release candidate 1

1.23.104.2 Core and Builtins
............................

   - bpo-29073(1): bytearray formatting no longer truncates on first
     null byte.

   - bpo-28932(2): Do not include <sys/random.h> if it does not exist.

   - bpo-28147(3): Fix a memory leak in split-table dictionaries:
     setattr() must not convert combined table into split table.

   - bpo-25677(4): Correct the positioning of the syntax error caret for
     indented blocks.  Based on patch by Michael Layzell.

   - bpo-29000(5): Fixed bytes formatting of octals with zero padding in
     alternate form.

   - bpo-28512(6): Fixed setting the offset attribute of SyntaxError by
     PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().

   - bpo-28991(7): functools.lru_cache() was susceptible to an obscure
     reentrancy bug caused by a monkey-patched len() function.

   - bpo-28648(8): Fixed crash in Py_DecodeLocale() in debug build on
     Mac OS X when decode astral characters.  Patch by Xiang Zhang.

   - bpo-19398(9): Extra slash no longer added to sys.path components in
     case of empty compile-time PYTHONPATH components.

   - bpo-28426(10): Fixed potential crash in PyUnicode_AsDecodedObject()
     in debug build.

   - bpo-23782(11): Fixed possible memory leak in _PyTraceback_Add() and
     exception loss in PyTraceBack_Here().

   - bpo-28379(12): Added sanity checks and tests for
     PyUnicode_CopyCharacters().  Patch by Xiang Zhang.

   - bpo-28376(13): The type of long range iterator is now registered as
     Iterator.  Patch by Oren Milman.

   - bpo-28376(14): The constructor of range_iterator now checks that
     step is not 0.  Patch by Oren Milman.

   - bpo-26906(15): Resolving special methods of uninitialized type now
     causes implicit initialization of the type instead of a fail.

   - bpo-18287(16): PyType_Ready() now checks that tp_name is not NULL.
     Original patch by Niklas Koep.

   - bpo-24098(17): Fixed possible crash when AST is changed in process
     of compiling it.

   - bpo-28350(18): String constants with null character no longer
     interned.

   - bpo-26617(19): Fix crash when GC runs during weakref callbacks.

   - bpo-27942(20): String constants now interned recursively in tuples
     and frozensets.

   - bpo-21578(21): Fixed misleading error message when ImportError
     called with invalid keyword args.

   - bpo-28203(22): Fix incorrect type in error message from
     ‘complex(1.0, {2:3})’.  Patch by Soumya Sharma.

   - bpo-27955(23): Fallback on reading /dev/urandom device when the
     getrandom() syscall fails with EPERM, for example when blocked by
     SECCOMP.

   - bpo-28131(24): Fix a regression in zipimport’s compile_source().
     zipimport should use the same optimization level as the
     interpreter.

   - bpo-25221(25): Fix corrupted result from PyLong_FromLong(0) when
     Python is compiled with NSMALLPOSINTS = 0.

   - bpo-25758(26): Prevents zipimport from unnecessarily encoding a
     filename (patch by Eryk Sun)

   - bpo-28189(27): dictitems_contains no longer swallows compare
     errors.  (Patch by Xiang Zhang)

   - bpo-27812(28): Properly clear out a generator’s frame’s
     backreference to the generator to prevent crashes in frame.clear().

   - bpo-27811(29): Fix a crash when a coroutine that has not been
     awaited is finalized with warnings-as-errors enabled.

   - bpo-27587(30): Fix another issue found by PVS-Studio: Null pointer
     check after use of ‘def’ in _PyState_AddModule().  Initial patch by
     Christian Heimes.

   - bpo-26020(31): set literal evaluation order did not match
     documented behaviour.

   - bpo-27782(32): Multi-phase extension module import now correctly
     allows the ‘m_methods’ field to be used to add module level
     functions to instances of non-module types returned from
     ‘Py_create_mod’.  Patch by Xiang Zhang.

   - bpo-27936(33): The round() function accepted a second None argument
     for some types but not for others.  Fixed the inconsistency by
     accepting None for all numeric types.

   - bpo-27487(34): Warn if a submodule argument to “python -m” or
     runpy.run_module() is found in sys.modules after parent packages
     are imported, but before the submodule is executed.

   - bpo-27558(35): Fix a SystemError in the implementation of “raise”
     statement.  In a brand new thread, raise a RuntimeError since there
     is no active exception to reraise.  Patch written by Xiang Zhang.

   - bpo-27419(36): Standard __import__() no longer look up “__import__”
     in globals or builtins for importing submodules or “from import”.
     Fixed handling an error of non-string package name.

   - bpo-27083(37): Respect the PYTHONCASEOK environment variable under
     Windows.

   - bpo-27514(38): Make having too many statically nested blocks a
     SyntaxError instead of SystemError.

   - bpo-27473(39): Fixed possible integer overflow in bytes and
     bytearray concatenations.  Patch by Xiang Zhang.

   - bpo-27507(40): Add integer overflow check in bytearray.extend().
     Patch by Xiang Zhang.

   - bpo-27581(41): Don’t rely on wrapping for overflow check in
     PySequence_Tuple().  Patch by Xiang Zhang.

   - bpo-27443(42): __length_hint__() of bytearray iterators no longer
     return a negative integer for a resized bytearray.

   - bpo-27942(43): Fix memory leak in codeobject.c

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29073

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28932

   (3) https://bugs.python.org/issue?@action=redirect&bpo=28147

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25677

   (5) https://bugs.python.org/issue?@action=redirect&bpo=29000

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28512

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28991

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28648

   (9) https://bugs.python.org/issue?@action=redirect&bpo=19398

   (10) https://bugs.python.org/issue?@action=redirect&bpo=28426

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23782

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28379

   (13) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28376

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26906

   (16) https://bugs.python.org/issue?@action=redirect&bpo=18287

   (17) https://bugs.python.org/issue?@action=redirect&bpo=24098

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28350

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26617

   (20) https://bugs.python.org/issue?@action=redirect&bpo=27942

   (21) https://bugs.python.org/issue?@action=redirect&bpo=21578

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28203

   (23) https://bugs.python.org/issue?@action=redirect&bpo=27955

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28131

   (25) https://bugs.python.org/issue?@action=redirect&bpo=25221

   (26) https://bugs.python.org/issue?@action=redirect&bpo=25758

   (27) https://bugs.python.org/issue?@action=redirect&bpo=28189

   (28) https://bugs.python.org/issue?@action=redirect&bpo=27812

   (29) https://bugs.python.org/issue?@action=redirect&bpo=27811

   (30) https://bugs.python.org/issue?@action=redirect&bpo=27587

   (31) https://bugs.python.org/issue?@action=redirect&bpo=26020

   (32) https://bugs.python.org/issue?@action=redirect&bpo=27782

   (33) https://bugs.python.org/issue?@action=redirect&bpo=27936

   (34) https://bugs.python.org/issue?@action=redirect&bpo=27487

   (35) https://bugs.python.org/issue?@action=redirect&bpo=27558

   (36) https://bugs.python.org/issue?@action=redirect&bpo=27419

   (37) https://bugs.python.org/issue?@action=redirect&bpo=27083

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27514

   (39) https://bugs.python.org/issue?@action=redirect&bpo=27473

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27507

   (41) https://bugs.python.org/issue?@action=redirect&bpo=27581

   (42) https://bugs.python.org/issue?@action=redirect&bpo=27443

   (43) https://bugs.python.org/issue?@action=redirect&bpo=27942


File: python.info,  Node: Library<169>,  Next: IDLE<61>,  Prev: Core and Builtins<166>,  Up: Python 3 5 3 release candidate 1

1.23.104.3 Library
..................

   - bpo-15812(1): inspect.getframeinfo() now correctly shows the first
     line of a context.  Patch by Sam Breese.

   - bpo-29094(2): Offsets in a ZIP file created with extern file object
     and modes “w” and “x” now are relative to the start of the file.

   - bpo-13051(3): Fixed recursion errors in large or resized
     curses.textpad.Textbox.  Based on patch by Tycho Andersen.

   - bpo-29119(4): Fix weakrefs in the pure python version of
     collections.OrderedDict move_to_end() method.  Contributed by Andra
     Bogildea.

   - bpo-9770(5): curses.ascii predicates now work correctly with
     negative integers.

   - bpo-28427(6): old keys should not remove new values from
     WeakValueDictionary when collecting from another thread.

   - bpo-28923(7): Remove editor artifacts from Tix.py.

   - bpo-28871(8): Fixed a crash when deallocate deep ElementTree.

   - bpo-19542(9): Fix bugs in WeakValueDictionary.setdefault() and
     WeakValueDictionary.pop() when a GC collection happens in another
     thread.

   - bpo-20191(10): Fixed a crash in resource.prlimit() when pass a
     sequence that doesn’t own its elements as limits.

   - bpo-28779(11): multiprocessing.set_forkserver_preload() would crash
     the forkserver process if a preloaded module instantiated some
     multiprocessing objects such as locks.

   - bpo-28847(12): dbm.dumb now supports reading read-only files and no
     longer writes the index file when it is not changed.

   - bpo-25659(13): In ctypes, prevent a crash calling the from_buffer()
     and from_buffer_copy() methods on abstract classes like Array.

   - bpo-28732(14): Fix crash in os.spawnv() with no elements in args

   - bpo-28485(15): Always raise ValueError for negative
     compileall.compile_dir(workers=…) parameter, even when
     multithreading is unavailable.

   - bpo-28387(16): Fixed possible crash in _io.TextIOWrapper
     deallocator when the garbage collector is invoked in other thread.
     Based on patch by Sebastian Cufre.

   - bpo-27517(17): LZMA compressor and decompressor no longer raise
     exceptions if given empty data twice.  Patch by Benjamin Fogle.

   - bpo-28549(18): Fixed segfault in curses’s addch() with ncurses6.

   - bpo-28449(19): tarfile.open() with mode “r” or “r:” now tries to
     open a tar file with compression before trying to open it without
     compression.  Otherwise it had 50% chance failed with
     ignore_zeros=True.

   - bpo-23262(20): The webbrowser module now supports Firefox 36+ and
     derived browsers.  Based on patch by Oleg Broytman.

   - bpo-27939(21): Fixed bugs in tkinter.ttk.LabeledScale and
     tkinter.Scale caused by representing the scale as float value
     internally in Tk.  tkinter.IntVar now works if float value is set
     to underlying Tk variable.

   - bpo-28255(22): calendar.TextCalendar().prmonth() no longer prints a
     space at the start of new line after printing a month’s calendar.
     Patch by Xiang Zhang.

   - bpo-20491(23): The textwrap.TextWrapper class now honors
     non-breaking spaces.  Based on patch by Kaarle Ritvanen.

   - bpo-28353(24): os.fwalk() no longer fails on broken links.

   - bpo-25464(25): Fixed HList.header_exists() in tkinter.tix module by
     addin a workaround to Tix library bug.

   - bpo-28488(26): shutil.make_archive() no longer add entry “./” to
     ZIP archive.

   - bpo-24452(27): Make webbrowser support Chrome on Mac OS X.

   - bpo-20766(28): Fix references leaked by pdb in the handling of
     SIGINT handlers.

   - bpo-26293(29): Fixed writing ZIP files that starts not from the
     start of the file.  Offsets in ZIP file now are relative to the
     start of the archive in conforming to the specification.

   - bpo-28321(30): Fixed writing non-BMP characters with binary format
     in plistlib.

   - bpo-28322(31): Fixed possible crashes when unpickle itertools
     objects from incorrect pickle data.  Based on patch by John Leitch.

   - Fix possible integer overflows and crashes in the mmap module with
     unusual usage patterns.

   - bpo-1703178(32): Fix the ability to pass the –link-objects option
     to the distutils build_ext command.

   - bpo-28253(33): Fixed calendar functions for extreme months: 0001-01
     and 9999-12.  Methods itermonthdays() and itermonthdays2() are
     reimplemented so that they don’t call itermonthdates() which can
     cause datetime.date under/overflow.

   - bpo-28275(34): Fixed possible use after free in the decompress()
     methods of the LZMADecompressor and BZ2Decompressor classes.
     Original patch by John Leitch.

   - bpo-27897(35): Fixed possible crash in
     sqlite3.Connection.create_collation() if pass invalid string-like
     object as a name.  Patch by Xiang Zhang.

   - bpo-18893(36): Fix invalid exception handling in
     Lib/ctypes/macholib/dyld.py.  Patch by Madison May.

   - bpo-27611(37): Fixed support of default root window in the
     tkinter.tix module.

   - bpo-27348(38): In the traceback module, restore the formatting of
     exception messages like “Exception: None”.  This fixes a regression
     introduced in 3.5a2.

   - bpo-25651(39): Allow false values to be used for msg parameter of
     subTest().

   - bpo-27932(40): Prevent memory leak in win32_ver().

   - Fix UnboundLocalError in socket._sendfile_use_sendfile.

   - bpo-28075(41): Check for ERROR_ACCESS_DENIED in Windows
     implementation of os.stat().  Patch by Eryk Sun.

   - bpo-25270(42): Prevent codecs.escape_encode() from raising
     SystemError when an empty bytestring is passed.

   - bpo-28181(43): Get antigravity over HTTPS. Patch by Kaartic
     Sivaraam.

   - bpo-25895(44): Enable WebSocket URL schemes in
     urllib.parse.urljoin.  Patch by Gergely Imreh and Markus
     Holtermann.

   - bpo-27599(45): Fixed buffer overrun in binascii.b2a_qp() and
     binascii.a2b_qp().

   - bpo-19003(46): m email.generator now replaces only ‘\r’ and/or ‘\n’
     line endings, per the RFC, instead of all unicode line endings.

   - bpo-28019(47): itertools.count() no longer rounds non-integer step
     in range between 1.0 and 2.0 to 1.

   - bpo-25969(48): Update the lib2to3 grammar to handle the unpacking
     generalizations added in 3.5.

   - bpo-14977(49): mailcap now respects the order of the lines in the
     mailcap files (“first match”), as required by RFC 1542.  Patch by
     Michael Lazar.

   - bpo-24594(50): Validates persist parameter when opening MSI
     database

   - bpo-17582(51): xml.etree.ElementTree nows preserves whitespaces in
     attributes (Patch by Duane Griffin.  Reviewed and approved by
     Stefan Behnel.)

   - bpo-28047(52): Fixed calculation of line length used for the base64
     CTE in the new email policies.

   - bpo-27445(53): Don’t pass str(_charset) to MIMEText.set_payload().
     Patch by Claude Paroz.

   - bpo-22450(54): urllib now includes an ‘Accept: */*’ header among
     the default headers.  This makes the results of REST API requests
     more consistent and predictable especially when proxy servers are
     involved.

   - lib2to3.pgen3.driver.load_grammar() now creates a stable cache file
     between runs given the same Grammar.txt input regardless of the
     hash randomization setting.

   - bpo-27570(55): Avoid zero-length memcpy() etc calls with null
     source pointers in the “ctypes” and “array” modules.

   - bpo-22233(56): Break email header lines 'only' on the RFC specified
     CR and LF characters, not on arbitrary unicode line breaks.  This
     also fixes a bug in HTTP header parsing.

   - bpo-27988(57): Fix email iter_attachments incorrect mutation of
     payload list.

   - bpo-27691(58): Fix ssl module’s parsing of GEN_RID subject
     alternative name fields in X.509 certs.

   - bpo-27850(59): Remove 3DES from ssl module’s default cipher list to
     counter measure sweet32 attack ( CVE 2016-2183(60)).

   - bpo-27766(61): Add ChaCha20 Poly1305 to ssl module’s default cipher
     list.  (Required OpenSSL 1.1.0 or LibreSSL).

   - bpo-26470(62): Port ssl and hashlib module to OpenSSL 1.1.0.

   - Remove support for passing a file descriptor to os.access.  It
     never worked but previously didn’t raise.

   - bpo-12885(63): Fix error when distutils encounters symlink.

   - bpo-27881(64): Fixed possible bugs when setting
     sqlite3.Connection.isolation_level.  Based on patch by Xiang Zhang.

   - bpo-27861(65): Fixed a crash in sqlite3.Connection.cursor() when a
     factory creates not a cursor.  Patch by Xiang Zhang.

   - bpo-19884(66): Avoid spurious output on OS X with Gnu Readline.

   - bpo-27706(67): Restore deterministic behavior of
     random.Random().seed() for string seeds using seeding version 1.
     Allows sequences of calls to random() to exactly match those
     obtained in Python 2.  Patch by Nofar Schnider.

   - bpo-10513(68): Fix a regression in Connection.commit().  Statements
     should not be reset after a commit.

   - A new version of typing.py from ‘https://github.com/python/typing’:
     Collection (only for 3.6) (bpo-27598(69)).  Add FrozenSet to
     __all__ (upstream #261).  Fix crash in _get_type_vars() (upstream
     #259).  Remove the dict constraint in ForwardRef._eval_type
     (upstream #252).

   - bpo-27539(70): Fix unnormalised ‘Fraction.__pow__’ result in the
     case of negative exponent and negative base.

   - bpo-21718(71): cursor.description is now available for queries
     using CTEs.

   - bpo-2466(72): posixpath.ismount now correctly recognizes mount
     points which the user does not have permission to access.

   - bpo-27773(73): Correct some memory management errors
     server_hostname in _ssl.wrap_socket().

   - bpo-26750(74): unittest.mock.create_autospec() now works properly
     for subclasses of property() and other data descriptors.

   - In the curses module, raise an error if window.getstr() or
     window.instr() is passed a negative value.

   - bpo-27783(75): Fix possible usage of uninitialized memory in
     operator.methodcaller.

   - bpo-27774(76): Fix possible Py_DECREF on unowned object in _sre.

   - bpo-27760(77): Fix possible integer overflow in binascii.b2a_qp.

   - bpo-27758(78): Fix possible integer overflow in the _csv module for
     large record lengths.

   - bpo-27568(79): Prevent HTTPoxy attack ( CVE 2016-1000110(80)).
     Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is
     set, which indicates that the script is in CGI mode.

   - bpo-27656(81): Do not assume sched.h defines any SCHED_* constants.

   - bpo-27130(82): In the “zlib” module, fix handling of large buffers
     (typically 4 GiB) when compressing and decompressing.  Previously,
     inputs were limited to 4 GiB, and compression and decompression
     operations did not properly handle results of 4 GiB.

   - bpo-27533(83): Release GIL in nt._isdir

   - bpo-17711(84): Fixed unpickling by the persistent ID with protocol
     0.  Original patch by Alexandre Vassalotti.

   - bpo-27522(85): Avoid an unintentional reference cycle in
     email.feedparser.

   - bpo-26844(86): Fix error message for imp.find_module() to refer to
     ‘path’ instead of ‘name’.  Patch by Lev Maximov.

   - bpo-23804(87): Fix SSL zero-length recv() calls to not block and
     not raise an error about unclean EOF.

   - bpo-27466(88): Change time format returned by
     http.cookie.time2netscape, confirming the netscape cookie format
     and making it consistent with documentation.

   - bpo-26664(89): Fix activate.fish by removing mis-use of ‘$’.

   - bpo-22115(90): Fixed tracing Tkinter variables: trace_vdelete()
     with wrong mode no longer break tracing, trace_vinfo() now always
     returns a list of pairs of strings, tracing in the “u” mode now
     works.

   - Fix a scoping issue in importlib.util.LazyLoader which triggered an
     UnboundLocalError when lazy-loading a module that was already put
     into sys.modules.

   - bpo-27079(91): Fixed curses.ascii functions isblank(), iscntrl()
     and ispunct().

   - bpo-26754(92): Some functions (compile() etc) accepted a filename
     argument encoded as an iterable of integers.  Now only strings and
     byte-like objects are accepted.

   - bpo-27048(93): Prevents distutils failing on Windows when
     environment variables contain non-ASCII characters

   - bpo-27330(94): Fixed possible leaks in the ctypes module.

   - bpo-27238(95): Got rid of bare excepts in the turtle module.
     Original patch by Jelle Zijlstra.

   - bpo-27122(96): When an exception is raised within the context being
     managed by a contextlib.ExitStack() and one of the exit stack
     generators catches and raises it in a chain, do not re-raise the
     original exception when exiting, let the new chained one through.
     This avoids the PEP 479(97) bug described in issue25782.

   - bpo-26386(98): Fixed ttk.TreeView selection operations with item
     id’s containing spaces.

   - bpo-16182(99): Fix various functions in the “readline” module to
     use the locale encoding, and fix get_begidx() and get_endidx() to
     return code point indexes.

   - bpo-27392(100): Add loop.connect_accepted_socket().  Patch by Jim
     Fulton.

   - bpo-27930(101): Improved behaviour of
     logging.handlers.QueueListener.  Thanks to Paulo Andrade and Petr
     Viktorin for the analysis and patch.

   - bpo-21201(102): Improves readability of multiprocessing error
     message.  Thanks to Wojciech Walczak for patch.

   - bpo-27456(103): asyncio: Set TCP_NODELAY by default.

   - bpo-27906(104): Fix socket accept exhaustion during high TCP
     traffic.  Patch by Kevin Conway.

   - bpo-28174(105): Handle when SO_REUSEPORT isn’t properly supported.
     Patch by Seth Michael Larson.

   - bpo-26654(106): Inspect functools.partial in
     asyncio.Handle.__repr__.  Patch by iceboy.

   - bpo-26909(107): Fix slow pipes IO in asyncio.  Patch by INADA
     Naoki.

   - bpo-28176(108): Fix callbacks race in
     asyncio.SelectorLoop.sock_connect.

   - bpo-27759(109): Fix selectors incorrectly retain invalid file
     descriptors.  Patch by Mark Williams.

   - bpo-28368(110): Refuse monitoring processes if the child watcher
     has no loop attached.  Patch by Vincent Michel.

   - bpo-28369(111): Raise RuntimeError when transport’s FD is used with
     add_reader, add_writer, etc.

   - bpo-28370(112): Speedup asyncio.StreamReader.readexactly.  Patch by
     Коренберг Марк.

   - bpo-28371(113): Deprecate passing asyncio.Handles to
     run_in_executor.

   - bpo-28372(114): Fix asyncio to support formatting of non-python
     coroutines.

   - bpo-28399(115): Remove UNIX socket from FS before binding.  Patch
     by Коренберг Марк.

   - bpo-27972(116): Prohibit Tasks to await on themselves.

   - bpo-26923(117): Fix asyncio.Gather to refuse being cancelled once
     all children are done.  Patch by Johannes Ebke.

   - bpo-26796(118): Don’t configure the number of workers for default
     threadpool executor.  Initial patch by Hans Lawrenz.

   - bpo-28600(119): Optimize loop.call_soon().

   - bpo-28613(120): Fix get_event_loop() return the current loop if
     called from coroutines/callbacks.

   - bpo-28639(121): Fix inspect.isawaitable to always return bool Patch
     by Justin Mayfield.

   - bpo-28652(122): Make loop methods reject socket kinds they do not
     support.

   - bpo-28653(123): Fix a refleak in functools.lru_cache.

   - bpo-28703(124): Fix asyncio.iscoroutinefunction to handle Mock
     objects.

   - bpo-24142(125): Reading a corrupt config file left the parser in an
     invalid state.  Original patch by Florian Höch.

   - bpo-28990(126): Fix SSL hanging if connection is closed before
     handshake completed.  (Patch by HoHo-Ho)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15812

   (2) https://bugs.python.org/issue?@action=redirect&bpo=29094

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13051

   (4) https://bugs.python.org/issue?@action=redirect&bpo=29119

   (5) https://bugs.python.org/issue?@action=redirect&bpo=9770

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28427

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28923

   (8) https://bugs.python.org/issue?@action=redirect&bpo=28871

   (9) https://bugs.python.org/issue?@action=redirect&bpo=19542

   (10) https://bugs.python.org/issue?@action=redirect&bpo=20191

   (11) https://bugs.python.org/issue?@action=redirect&bpo=28779

   (12) https://bugs.python.org/issue?@action=redirect&bpo=28847

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25659

   (14) https://bugs.python.org/issue?@action=redirect&bpo=28732

   (15) https://bugs.python.org/issue?@action=redirect&bpo=28485

   (16) https://bugs.python.org/issue?@action=redirect&bpo=28387

   (17) https://bugs.python.org/issue?@action=redirect&bpo=27517

   (18) https://bugs.python.org/issue?@action=redirect&bpo=28549

   (19) https://bugs.python.org/issue?@action=redirect&bpo=28449

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23262

   (21) https://bugs.python.org/issue?@action=redirect&bpo=27939

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28255

   (23) https://bugs.python.org/issue?@action=redirect&bpo=20491

   (24) https://bugs.python.org/issue?@action=redirect&bpo=28353

   (25) https://bugs.python.org/issue?@action=redirect&bpo=25464

   (26) https://bugs.python.org/issue?@action=redirect&bpo=28488

   (27) https://bugs.python.org/issue?@action=redirect&bpo=24452

   (28) https://bugs.python.org/issue?@action=redirect&bpo=20766

   (29) https://bugs.python.org/issue?@action=redirect&bpo=26293

   (30) https://bugs.python.org/issue?@action=redirect&bpo=28321

   (31) https://bugs.python.org/issue?@action=redirect&bpo=28322

   (32) https://bugs.python.org/issue?@action=redirect&bpo=1703178

   (33) https://bugs.python.org/issue?@action=redirect&bpo=28253

   (34) https://bugs.python.org/issue?@action=redirect&bpo=28275

   (35) https://bugs.python.org/issue?@action=redirect&bpo=27897

   (36) https://bugs.python.org/issue?@action=redirect&bpo=18893

   (37) https://bugs.python.org/issue?@action=redirect&bpo=27611

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27348

   (39) https://bugs.python.org/issue?@action=redirect&bpo=25651

   (40) https://bugs.python.org/issue?@action=redirect&bpo=27932

   (41) https://bugs.python.org/issue?@action=redirect&bpo=28075

   (42) https://bugs.python.org/issue?@action=redirect&bpo=25270

   (43) https://bugs.python.org/issue?@action=redirect&bpo=28181

   (44) https://bugs.python.org/issue?@action=redirect&bpo=25895

   (45) https://bugs.python.org/issue?@action=redirect&bpo=27599

   (46) https://bugs.python.org/issue?@action=redirect&bpo=19003

   (47) https://bugs.python.org/issue?@action=redirect&bpo=28019

   (48) https://bugs.python.org/issue?@action=redirect&bpo=25969

   (49) https://bugs.python.org/issue?@action=redirect&bpo=14977

   (50) https://bugs.python.org/issue?@action=redirect&bpo=24594

   (51) https://bugs.python.org/issue?@action=redirect&bpo=17582

   (52) https://bugs.python.org/issue?@action=redirect&bpo=28047

   (53) https://bugs.python.org/issue?@action=redirect&bpo=27445

   (54) https://bugs.python.org/issue?@action=redirect&bpo=22450

   (55) https://bugs.python.org/issue?@action=redirect&bpo=27570

   (56) https://bugs.python.org/issue?@action=redirect&bpo=22233

   (57) https://bugs.python.org/issue?@action=redirect&bpo=27988

   (58) https://bugs.python.org/issue?@action=redirect&bpo=27691

   (59) https://bugs.python.org/issue?@action=redirect&bpo=27850

   (60) https://www.cve.org/CVERecord?id=CVE-2016-2183

   (61) https://bugs.python.org/issue?@action=redirect&bpo=27766

   (62) https://bugs.python.org/issue?@action=redirect&bpo=26470

   (63) https://bugs.python.org/issue?@action=redirect&bpo=12885

   (64) https://bugs.python.org/issue?@action=redirect&bpo=27881

   (65) https://bugs.python.org/issue?@action=redirect&bpo=27861

   (66) https://bugs.python.org/issue?@action=redirect&bpo=19884

   (67) https://bugs.python.org/issue?@action=redirect&bpo=27706

   (68) https://bugs.python.org/issue?@action=redirect&bpo=10513

   (69) https://bugs.python.org/issue?@action=redirect&bpo=27598

   (70) https://bugs.python.org/issue?@action=redirect&bpo=27539

   (71) https://bugs.python.org/issue?@action=redirect&bpo=21718

   (72) https://bugs.python.org/issue?@action=redirect&bpo=2466

   (73) https://bugs.python.org/issue?@action=redirect&bpo=27773

   (74) https://bugs.python.org/issue?@action=redirect&bpo=26750

   (75) https://bugs.python.org/issue?@action=redirect&bpo=27783

   (76) https://bugs.python.org/issue?@action=redirect&bpo=27774

   (77) https://bugs.python.org/issue?@action=redirect&bpo=27760

   (78) https://bugs.python.org/issue?@action=redirect&bpo=27758

   (79) https://bugs.python.org/issue?@action=redirect&bpo=27568

   (80) https://www.cve.org/CVERecord?id=CVE-2016-1000110

   (81) https://bugs.python.org/issue?@action=redirect&bpo=27656

   (82) https://bugs.python.org/issue?@action=redirect&bpo=27130

   (83) https://bugs.python.org/issue?@action=redirect&bpo=27533

   (84) https://bugs.python.org/issue?@action=redirect&bpo=17711

   (85) https://bugs.python.org/issue?@action=redirect&bpo=27522

   (86) https://bugs.python.org/issue?@action=redirect&bpo=26844

   (87) https://bugs.python.org/issue?@action=redirect&bpo=23804

   (88) https://bugs.python.org/issue?@action=redirect&bpo=27466

   (89) https://bugs.python.org/issue?@action=redirect&bpo=26664

   (90) https://bugs.python.org/issue?@action=redirect&bpo=22115

   (91) https://bugs.python.org/issue?@action=redirect&bpo=27079

   (92) https://bugs.python.org/issue?@action=redirect&bpo=26754

   (93) https://bugs.python.org/issue?@action=redirect&bpo=27048

   (94) https://bugs.python.org/issue?@action=redirect&bpo=27330

   (95) https://bugs.python.org/issue?@action=redirect&bpo=27238

   (96) https://bugs.python.org/issue?@action=redirect&bpo=27122

   (97) https://peps.python.org/pep-0479/

   (98) https://bugs.python.org/issue?@action=redirect&bpo=26386

   (99) https://bugs.python.org/issue?@action=redirect&bpo=16182

   (100) https://bugs.python.org/issue?@action=redirect&bpo=27392

   (101) https://bugs.python.org/issue?@action=redirect&bpo=27930

   (102) https://bugs.python.org/issue?@action=redirect&bpo=21201

   (103) https://bugs.python.org/issue?@action=redirect&bpo=27456

   (104) https://bugs.python.org/issue?@action=redirect&bpo=27906

   (105) https://bugs.python.org/issue?@action=redirect&bpo=28174

   (106) https://bugs.python.org/issue?@action=redirect&bpo=26654

   (107) https://bugs.python.org/issue?@action=redirect&bpo=26909

   (108) https://bugs.python.org/issue?@action=redirect&bpo=28176

   (109) https://bugs.python.org/issue?@action=redirect&bpo=27759

   (110) https://bugs.python.org/issue?@action=redirect&bpo=28368

   (111) https://bugs.python.org/issue?@action=redirect&bpo=28369

   (112) https://bugs.python.org/issue?@action=redirect&bpo=28370

   (113) https://bugs.python.org/issue?@action=redirect&bpo=28371

   (114) https://bugs.python.org/issue?@action=redirect&bpo=28372

   (115) https://bugs.python.org/issue?@action=redirect&bpo=28399

   (116) https://bugs.python.org/issue?@action=redirect&bpo=27972

   (117) https://bugs.python.org/issue?@action=redirect&bpo=26923

   (118) https://bugs.python.org/issue?@action=redirect&bpo=26796

   (119) https://bugs.python.org/issue?@action=redirect&bpo=28600

   (120) https://bugs.python.org/issue?@action=redirect&bpo=28613

   (121) https://bugs.python.org/issue?@action=redirect&bpo=28639

   (122) https://bugs.python.org/issue?@action=redirect&bpo=28652

   (123) https://bugs.python.org/issue?@action=redirect&bpo=28653

   (124) https://bugs.python.org/issue?@action=redirect&bpo=28703

   (125) https://bugs.python.org/issue?@action=redirect&bpo=24142

   (126) https://bugs.python.org/issue?@action=redirect&bpo=28990


File: python.info,  Node: IDLE<61>,  Next: C API<75>,  Prev: Library<169>,  Up: Python 3 5 3 release candidate 1

1.23.104.4 IDLE
...............

   - bpo-15308(1): Add ‘interrupt execution’ (^C) to Shell menu.  Patch
     by Roger Serwy, updated by Bayard Randel.

   - bpo-27922(2): Stop IDLE tests from ‘flashing’ gui widgets on the
     screen.

   - Add version to title of IDLE help window.

   - bpo-25564(3): In section on IDLE – console differences, mention
     that using exec means that __builtins__ is defined for each
     statement.

   - bpo-27714(4): text_textview and test_autocomplete now pass when
     re-run in the same process.  This occurs when test_idle fails when
     run with the -w option but without -jn.  Fix warning from
     test_config.

   - bpo-25507(5): IDLE no longer runs buggy code because of its tkinter
     imports.  Users must include the same imports required to run
     directly in Python.

   - bpo-27452(6): add line counter and crc to IDLE configHandler test
     dump.

   - bpo-27365(7): Allow non-ascii chars in IDLE NEWS.txt, for
     contributor names.

   - bpo-27245(8): IDLE: Cleanly delete custom themes and key bindings.
     Previously, when IDLE was started from a console or by import, a
     cascade of warnings was emitted.  Patch by Serhiy Storchaka.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15308

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27922

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25564

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27714

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25507

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27452

   (7) https://bugs.python.org/issue?@action=redirect&bpo=27365

   (8) https://bugs.python.org/issue?@action=redirect&bpo=27245


File: python.info,  Node: C API<75>,  Next: Documentation<77>,  Prev: IDLE<61>,  Up: Python 3 5 3 release candidate 1

1.23.104.5 C API
................

   - bpo-28808(1): PyUnicode_CompareWithASCIIString() now never raises
     exceptions.

   - bpo-26754(2): PyUnicode_FSDecoder() accepted a filename argument
     encoded as an iterable of integers.  Now only strings and
     bytes-like objects are accepted.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28808

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26754


File: python.info,  Node: Documentation<77>,  Next: Tests<81>,  Prev: C API<75>,  Up: Python 3 5 3 release candidate 1

1.23.104.6 Documentation
........................

   - bpo-28513(1): Documented command-line interface of zipfile.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28513


File: python.info,  Node: Tests<81>,  Next: Tools/Demos<48>,  Prev: Documentation<77>,  Up: Python 3 5 3 release candidate 1

1.23.104.7 Tests
................

   - bpo-28950(1): Disallow -j0 to be combined with -T/-l/-M in regrtest
     command line arguments.

   - bpo-28666(2): Now test.support.rmtree is able to remove unwritable
     or unreadable directories.

   - bpo-23839(3): Various caches now are cleared before running every
     test file.

   - bpo-28409(4): regrtest: fix the parser of command line arguments.

   - bpo-27787(5): Call gc.collect() before checking each test for
     “dangling threads”, since the dangling threads are weak references.

   - bpo-27369(6): In test_pyexpat, avoid testing an error message
     detail that changed in Expat 2.2.0.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28950

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28666

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23839

   (4) https://bugs.python.org/issue?@action=redirect&bpo=28409

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27787

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27369


File: python.info,  Node: Tools/Demos<48>,  Next: Windows<76>,  Prev: Tests<81>,  Up: Python 3 5 3 release candidate 1

1.23.104.8 Tools/Demos
......................

   - bpo-27952(1): Get Tools/scripts/fixcid.py working with Python 3 and
     the current “re” module, avoid invalid Python backslash escapes,
     and fix a bug parsing escaped C quote signs.

   - bpo-27332(2): Fixed the type of the first argument of module-level
     functions generated by Argument Clinic.  Patch by Petr Viktorin.

   - bpo-27418(3): Fixed Tools/importbench/importbench.py.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27952

   (2) https://bugs.python.org/issue?@action=redirect&bpo=27332

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27418


File: python.info,  Node: Windows<76>,  Next: Build<89>,  Prev: Tools/Demos<48>,  Up: Python 3 5 3 release candidate 1

1.23.104.9 Windows
..................

   - bpo-28251(1): Improvements to help manuals on Windows.

   - bpo-28110(2): launcher.msi has different product codes between
     32-bit and 64-bit

   - bpo-25144(3): Ensures TargetDir is set before continuing with
     custom install.

   - bpo-27469(4): Adds a shell extension to the launcher so that drag
     and drop works correctly.

   - bpo-27309(5): Enabled proper Windows styles in python[w].exe
     manifest.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28251

   (2) https://bugs.python.org/issue?@action=redirect&bpo=28110

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25144

   (4) https://bugs.python.org/issue?@action=redirect&bpo=27469

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27309


File: python.info,  Node: Build<89>,  Prev: Windows<76>,  Up: Python 3 5 3 release candidate 1

1.23.104.10 Build
.................

   - bpo-29080(1): Removes hard dependency on hg.exe from
     PCBuild/build.bat

   - bpo-23903(2): Added missed names to PC/python3.def.

   - bpo-10656(3): Fix out-of-tree building on AIX. Patch by Tristan
     Carel and Michael Haubenwallner.

   - bpo-26359(4): Rename –with-optimiations to –enable-optimizations.

   - bpo-28444(5): Fix missing extensions modules when cross compiling.

   - bpo-28248(6): Update Windows build and OS X installers to use
     OpenSSL 1.0.2j.

   - bpo-28258(7): Fixed build with Estonian locale (python-config and
     distclean targets in Makefile).  Patch by Arfrever Frehtes
     Taifersar Arahesis.

   - bpo-26661(8): setup.py now detects system libffi with multiarch
     wrapper.

   - bpo-28066(9): Fix the logic that searches build directories for
     generated include files when building outside the source tree.

   - bpo-15819(10): Remove redundant include search directory option for
     building outside the source tree.

   - bpo-27566(11): Fix clean target in freeze makefile (patch by Lisa
     Roach)

   - bpo-27705(12): Update message in validate_ucrtbase.py

   - bpo-27983(13): Cause lack of llvm-profdata tool when using clang as
     required for PGO linking to be a configure time error rather than
     make time when –with-optimizations is enabled.  Also improve our
     ability to find the llvm-profdata tool on MacOS and some Linuxes.

   - bpo-26307(14): The profile-opt build now applies PGO to the
     built-in modules.

   - bpo-26359(15): Add the –with-optimizations configure flag.

   - bpo-27713(16): Suppress spurious build warnings when updating
     importlib’s bootstrap files.  Patch by Xiang Zhang

   - bpo-25825(17): Correct the references to Modules/python.exp and
     ld_so_aix, which are required on AIX. This updates references to an
     installation path that was changed in 3.2a4, and undoes changed
     references to the build tree that were made in 3.5.0a1.

   - bpo-27453(18): CPP invocation in configure must use CPPFLAGS. Patch
     by Chi Hsuan Yen.

   - bpo-27641(19): The configure script now inserts comments into the
     makefile to prevent the pgen and _freeze_importlib executables from
     being cross-compiled.

   - bpo-26662(20): Set PYTHON_FOR_GEN in configure as the Python
     program to be used for file generation during the build.

   - bpo-10910(21): Avoid C++ compilation errors on FreeBSD and OS X.
     Also update FreedBSD version checks for the original ctype UTF-8
     workaround.

   - bpo-28676(22): Prevent missing ‘getentropy’ declaration warning on
     macOS. Patch by Gareth Rees.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=29080

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23903

   (3) https://bugs.python.org/issue?@action=redirect&bpo=10656

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (5) https://bugs.python.org/issue?@action=redirect&bpo=28444

   (6) https://bugs.python.org/issue?@action=redirect&bpo=28248

   (7) https://bugs.python.org/issue?@action=redirect&bpo=28258

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26661

   (9) https://bugs.python.org/issue?@action=redirect&bpo=28066

   (10) https://bugs.python.org/issue?@action=redirect&bpo=15819

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27566

   (12) https://bugs.python.org/issue?@action=redirect&bpo=27705

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27983

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26307

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26359

   (16) https://bugs.python.org/issue?@action=redirect&bpo=27713

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25825

   (18) https://bugs.python.org/issue?@action=redirect&bpo=27453

   (19) https://bugs.python.org/issue?@action=redirect&bpo=27641

   (20) https://bugs.python.org/issue?@action=redirect&bpo=26662

   (21) https://bugs.python.org/issue?@action=redirect&bpo=10910

   (22) https://bugs.python.org/issue?@action=redirect&bpo=28676


File: python.info,  Node: Python 3 5 2 final,  Next: Python 3 5 2 release candidate 1,  Prev: Python 3 5 3 release candidate 1,  Up: Changelog

1.23.105 Python 3.5.2 final
---------------------------

'Release date: 2016-06-26'

* Menu:

* Core and Builtins: Core and Builtins<167>.
* Tests: Tests<82>.
* IDLE: IDLE<62>.


File: python.info,  Node: Core and Builtins<167>,  Next: Tests<82>,  Up: Python 3 5 2 final

1.23.105.1 Core and Builtins
............................

   - bpo-26930(1): Update Windows builds to use OpenSSL 1.0.2h.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26930


File: python.info,  Node: Tests<82>,  Next: IDLE<62>,  Prev: Core and Builtins<167>,  Up: Python 3 5 2 final

1.23.105.2 Tests
................

   - bpo-26867(1): Ubuntu’s openssl OP_NO_SSLv3 is forced on by default;
     fix test.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26867


File: python.info,  Node: IDLE<62>,  Prev: Tests<82>,  Up: Python 3 5 2 final

1.23.105.3 IDLE
...............

   - bpo-27365(1): Allow non-ascii in idlelib/NEWS.txt - minimal part
     for 3.5.2.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27365


File: python.info,  Node: Python 3 5 2 release candidate 1,  Next: Python 3 5 1 final,  Prev: Python 3 5 2 final,  Up: Changelog

1.23.106 Python 3.5.2 release candidate 1
-----------------------------------------

'Release date: 2016-06-12'

* Menu:

* Security: Security<57>.
* Core and Builtins: Core and Builtins<168>.
* Library: Library<170>.
* IDLE: IDLE<63>.
* Documentation: Documentation<78>.
* Tests: Tests<83>.
* Build: Build<90>.
* Windows: Windows<77>.
* Tools/Demos: Tools/Demos<49>.


File: python.info,  Node: Security<57>,  Next: Core and Builtins<168>,  Up: Python 3 5 2 release candidate 1

1.23.106.1 Security
...................

   - bpo-26556(1): Update expat to 2.1.1, fixes CVE 2015-1283(2).

   - Fix TLS stripping vulnerability in smtplib, CVE 2016-0772(3).
     Reported by Team Oststrom.

   - bpo-26839(4): On Linux, *note os.urandom(): 526. now calls
     ‘getrandom()’ with ‘GRND_NONBLOCK’ to fall back on reading
     ‘/dev/urandom’ if the urandom entropy pool is not initialized yet.
     Patch written by Colm Buckley.

   - bpo-26657(5): Fix directory traversal vulnerability with
     http.server on Windows.  This fixes a regression that was
     introduced in 3.3.4rc1 and 3.4.0rc1.  Based on patch by Philipp
     Hagemeister.

   - bpo-26313(6): ssl.py _load_windows_store_certs fails if windows
     cert store is empty.  Patch by Baji.

   - bpo-25939(7): On Windows open the cert store readonly in
     ssl.enum_certificates.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26556

   (2) https://www.cve.org/CVERecord?id=CVE-2015-1283

   (3) https://www.cve.org/CVERecord?id=CVE-2016-0772

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26839

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26657

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26313

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25939


File: python.info,  Node: Core and Builtins<168>,  Next: Library<170>,  Prev: Security<57>,  Up: Python 3 5 2 release candidate 1

1.23.106.2 Core and Builtins
............................

   - bpo-27066(1): Fixed SystemError if a custom opener (for open())
     returns a negative number without setting an exception.

   - bpo-20041(2): Fixed TypeError when frame.f_trace is set to None.
     Patch by Xavier de Gaye.

   - bpo-26168(3): Fixed possible refleaks in failing Py_BuildValue()
     with the “N” format unit.

   - bpo-26991(4): Fix possible refleak when creating a function with
     annotations.

   - bpo-27039(5): Fixed bytearray.remove() for values greater than 127.
     Patch by Joe Jevnik.

   - bpo-23640(6): int.from_bytes() no longer bypasses constructors for
     subclasses.

   - bpo-26811(7): gc.get_objects() no longer contains a broken tuple
     with NULL pointer.

   - bpo-20120(8): Use RawConfigParser for .pypirc parsing, removing
     support for interpolation unintentionally added with move to Python
     3.  Behavior no longer does any interpolation in .pypirc files,
     matching behavior in Python 2.7 and Setuptools 19.0.

   - bpo-26659(9): Make the builtin slice type support cycle collection.

   - bpo-26718(10): super.__init__ no longer leaks memory if called
     multiple times.  NOTE: A direct call of super.__init__ is not
     endorsed!

   - bpo-25339(11): PYTHONIOENCODING now has priority over locale in
     setting the error handler for stdin and stdout.

   - bpo-26494(12): Fixed crash on iterating exhausting iterators.
     Affected classes are generic sequence iterators, iterators of str,
     bytes, bytearray, list, tuple, set, frozenset, dict, OrderedDict,
     corresponding views and os.scandir() iterator.

   - bpo-26581(13): If coding cookie is specified multiple times on a
     line in Python source code file, only the first one is taken to
     account.

   - bpo-26464(14): Fix str.translate() when string is ASCII and first
     replacements removes character, but next replacement uses a
     non-ASCII character or a string longer than 1 character.
     Regression introduced in Python 3.5.0.

   - bpo-22836(15): Ensure exception reports from PyErr_Display() and
     PyErr_WriteUnraisable() are sensible even when formatting them
     produces secondary errors.  This affects the reports produced by
     sys.__excepthook__() and when __del__() raises an exception.

   - bpo-26302(16): Correct behavior to reject comma as a legal
     character for cookie names.

   - bpo-4806(17): Avoid masking the original TypeError exception when
     using star (‘*’) unpacking in function calls.  Based on patch by
     Hagen Fürstenau and Daniel Urban.

   - bpo-27138(18): Fix the doc comment for FileFinder.find_spec().

   - bpo-26154(19): Add a new private _PyThreadState_UncheckedGet()
     function to get the current Python thread state, but don’t issue a
     fatal error if it is NULL. This new function must be used instead
     of accessing directly the _PyThreadState_Current variable.  The
     variable is no more exposed since Python 3.5.1 to hide the exact
     implementation of atomic C types, to avoid compiler issues.

   - bpo-26194(20): Deque.insert() gave odd results for bounded deques
     that had reached their maximum size.  Now an IndexError will be
     raised when attempting to insert into a full deque.

   - bpo-25843(21): When compiling code, don’t merge constants if they
     are equal but have a different types.  For example, ‘f1, f2 =
     lambda: 1, lambda: 1.0’ is now correctly compiled to two different
     functions: ‘f1()’ returns ‘1’ (‘int’) and ‘f2()’ returns ‘1.0’
     (‘int’), even if ‘1’ and ‘1.0’ are equal.

   - bpo-22995(22): [UPDATE] Comment out the one of the pickleability
     tests in _PyObject_GetState() due to regressions observed in
     Cython-based projects.

   - bpo-25961(23): Disallowed null characters in the type name.

   - bpo-25973(24): Fix segfault when an invalid nonlocal statement
     binds a name starting with two underscores.

   - bpo-22995(25): Instances of extension types with a state that
     aren’t subclasses of list or dict and haven’t implemented any
     pickle-related methods (__reduce__, __reduce_ex__, __getnewargs__,
     __getnewargs_ex__, or __getstate__), can no longer be pickled.
     Including memoryview.

   - bpo-20440(26): Massive replacing unsafe attribute setting code with
     special macro Py_SETREF.

   - bpo-25766(27): Special method __bytes__() now works in str
     subclasses.

   - bpo-25421(28): __sizeof__ methods of builtin types now use dynamic
     basic size.  This allows sys.getsize() to work correctly with their
     subclasses with __slots__ defined.

   - bpo-25709(29): Fixed problem with in-place string concatenation and
     utf-8 cache.

   - bpo-27147(30): Mention PEP 420(31) in the importlib docs.

   - bpo-24097(32): Fixed crash in object.__reduce__() if slot name is
     freed inside __getattr__.

   - bpo-24731(33): Fixed crash on converting objects with special
     methods __bytes__, __trunc__, and __float__ returning instances of
     subclasses of bytes, int, and float to subclasses of bytes, int,
     and float correspondingly.

   - bpo-26478(34): Fix semantic bugs when using binary operators with
     dictionary views and tuples.

   - bpo-26171(35): Fix possible integer overflow and heap corruption in
     zipimporter.get_data().

   - bpo-25660(36): Fix TAB key behaviour in REPL with readline.

   - bpo-25887(37): Raise a RuntimeError when a coroutine object is
     awaited more than once.

   - bpo-27243(38): Update the __aiter__ protocol: instead of returning
     an awaitable that resolves to an asynchronous iterator, the
     asynchronous iterator should be returned directly.  Doing the
     former will trigger a PendingDeprecationWarning.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27066

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20041

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26168

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26991

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27039

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23640

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26811

   (8) https://bugs.python.org/issue?@action=redirect&bpo=20120

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26659

   (10) https://bugs.python.org/issue?@action=redirect&bpo=26718

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25339

   (12) https://bugs.python.org/issue?@action=redirect&bpo=26494

   (13) https://bugs.python.org/issue?@action=redirect&bpo=26581

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26464

   (15) https://bugs.python.org/issue?@action=redirect&bpo=22836

   (16) https://bugs.python.org/issue?@action=redirect&bpo=26302

   (17) https://bugs.python.org/issue?@action=redirect&bpo=4806

   (18) https://bugs.python.org/issue?@action=redirect&bpo=27138

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26154

   (20) https://bugs.python.org/issue?@action=redirect&bpo=26194

   (21) https://bugs.python.org/issue?@action=redirect&bpo=25843

   (22) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (23) https://bugs.python.org/issue?@action=redirect&bpo=25961

   (24) https://bugs.python.org/issue?@action=redirect&bpo=25973

   (25) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (26) https://bugs.python.org/issue?@action=redirect&bpo=20440

   (27) https://bugs.python.org/issue?@action=redirect&bpo=25766

   (28) https://bugs.python.org/issue?@action=redirect&bpo=25421

   (29) https://bugs.python.org/issue?@action=redirect&bpo=25709

   (30) https://bugs.python.org/issue?@action=redirect&bpo=27147

   (31) https://peps.python.org/pep-0420/

   (32) https://bugs.python.org/issue?@action=redirect&bpo=24097

   (33) https://bugs.python.org/issue?@action=redirect&bpo=24731

   (34) https://bugs.python.org/issue?@action=redirect&bpo=26478

   (35) https://bugs.python.org/issue?@action=redirect&bpo=26171

   (36) https://bugs.python.org/issue?@action=redirect&bpo=25660

   (37) https://bugs.python.org/issue?@action=redirect&bpo=25887

   (38) https://bugs.python.org/issue?@action=redirect&bpo=27243


File: python.info,  Node: Library<170>,  Next: IDLE<63>,  Prev: Core and Builtins<168>,  Up: Python 3 5 2 release candidate 1

1.23.106.3 Library
..................

   - bpo-21386(1): Implement missing IPv4Address.is_global property.  It
     was documented since 07a5610bae9d.  Initial patch by Roger Luethi.

   - bpo-20900(2): distutils register command now decodes HTTP responses
     correctly.  Initial patch by ingrid.

   - A new version of typing.py provides several new classes and
     features: @overload outside stubs, Reversible, DefaultDict, Text,
     ContextManager, Type[], NewType(), TYPE_CHECKING, and numerous bug
     fixes (note that some of the new features are not yet implemented
     in mypy or other static analyzers).  Also classes for PEP 492(3)
     (Awaitable, AsyncIterable, AsyncIterator) have been added (in fact
     they made it into 3.5.1 but were never mentioned).

   - bpo-25738(4): Stop http.server.BaseHTTPRequestHandler.send_error()
     from sending a message body for 205 Reset Content.  Also, don’t
     send Content header fields in responses that don’t have a body.
     Patch by Susumu Koshiba.

   - bpo-21313(5): Fix the “platform” module to tolerate when
     sys.version contains truncated build information.

   - bpo-27164(6): In the zlib module, allow decompressing raw Deflate
     streams with a predefined zdict.  Based on patch by Xiang Zhang.

   - bpo-24291(7): Fix wsgiref.simple_server.WSGIRequestHandler to
     completely write data to the client.  Previously it could do
     partial writes and truncate data.  Also,
     wsgiref.handler.ServerHandler can now handle stdout doing partial
     writes, but this is deprecated.

   - bpo-26809(8): Add ‘__all__’ to *note string: d3.  Patch by Emanuel
     Barry.

   - bpo-26373(9): subprocess.Popen.communicate now correctly ignores
     BrokenPipeError when the child process dies before .communicate()
     is called in more/all circumstances.

   - bpo-21776(10): distutils.upload now correctly handles HTTPError.
     Initial patch by Claudiu Popa.

   - bpo-27114(11): Fix SSLContext._load_windows_store_certs fails with
     PermissionError

   - bpo-18383(12): Avoid creating duplicate filters when using
     filterwarnings and simplefilter.  Based on patch by Alex Shkop.

   - bpo-27057(13): Fix os.set_inheritable() on Android, ioctl() is
     blocked by SELinux and fails with EACCESS. The function now falls
     back to fcntl().  Patch written by Michał Bednarski.

   - bpo-27014(14): Fix infinite recursion using typing.py.  Thanks to
     Kalle Tuure!

   - bpo-14132(15): Fix urllib.request redirect handling when the target
     only has a query string.  Original fix by Ján Janech.

   - bpo-17214(16): The “urllib.request” module now percent-encodes
     non-ASCII bytes found in redirect target URLs.  Some servers send
     Location header fields with non-ASCII bytes, but “http.client”
     requires the request target to be ASCII-encodable, otherwise a
     UnicodeEncodeError is raised.  Based on patch by Christian Heimes.

   - bpo-26892(17): Honor debuglevel flag in urllib.request.HTTPHandler.
     Patch contributed by Chi Hsuan Yen.

   - bpo-22274(18): In the subprocess module, allow stderr to be
     redirected to stdout even when stdout is not redirected.  Patch by
     Akira Li.

   - bpo-26807(19): mock_open ‘files’ no longer error on readline at end
     of file.  Patch from Yolanda Robla.

   - bpo-25745(20): Fixed leaking a userptr in curses panel destructor.

   - bpo-26977(21): Removed unnecessary, and ignored, call to sum of
     squares helper in statistics.pvariance.

   - bpo-26881(22): The modulefinder module now supports extended opcode
     arguments.

   - bpo-23815(23): Fixed crashes related to directly created instances
     of types in _tkinter and curses.panel modules.

   - bpo-17765(24): weakref.ref() no longer silently ignores keyword
     arguments.  Patch by Georg Brandl.

   - bpo-26873(25): xmlrpc now raises ResponseError on unsupported type
     tags instead of silently return incorrect result.

   - bpo-26711(26): Fixed the comparison of plistlib.Data with other
     types.

   - bpo-24114(27): Fix an uninitialized variable in ‘ctypes.util’.  The
     bug only occurs on SunOS when the ctypes implementation searches
     for the ‘crle’ program.  Patch by Xiang Zhang.  Tested on SunOS by
     Kees Bos.

   - bpo-26864(28): In urllib.request, change the proxy bypass host
     checking against no_proxy to be case-insensitive, and to not match
     unrelated host names that happen to have a bypassed hostname as a
     suffix.  Patch by Xiang Zhang.

   - bpo-26634(29): recursive_repr() now sets __qualname__ of wrapper.
     Patch by Xiang Zhang.

   - bpo-26804(30): urllib.request will prefer lower_case proxy
     environment variables over UPPER_CASE or Mixed_Case ones.  Patch
     contributed by Hans-Peter Jansen.

   - bpo-26837(31): assertSequenceEqual() now correctly outputs
     non-stringified differing items (like bytes in the -b mode).  This
     affects assertListEqual() and assertTupleEqual().

   - bpo-26041(32): Remove “will be removed in Python 3.7” from
     deprecation messages of platform.dist() and
     platform.linux_distribution().  Patch by Kumaripaba Miyurusara
     Athukorala.

   - bpo-26822(33): itemgetter, attrgetter and methodcaller objects no
     longer silently ignore keyword arguments.

   - bpo-26733(34): Disassembling a class now disassembles class and
     static methods.  Patch by Xiang Zhang.

   - bpo-26801(35): Fix error handling in *note
     shutil.get_terminal_size(): 1147, catch *note AttributeError: 34e.
     instead of *note NameError: 442.  Patch written by Emanuel Barry.

   - bpo-24838(36): tarfile’s ustar and gnu formats now correctly
     calculate name and link field limits for multibyte character
     encodings like utf-8.

   - bpo-26717(37): Stop encoding Latin-1-ized WSGI paths with UTF-8.
     Patch by Anthony Sottile.

   - bpo-26735(38): Fix *note os.urandom(): 526. on Solaris 11.3 and
     newer when reading more than 1,024 bytes: call ‘getrandom()’
     multiple times with a limit of 1024 bytes per call.

   - bpo-16329(39): Add .webm to mimetypes.types_map.  Patch by
     Giampaolo Rodola’.

   - bpo-13952(40): Add .csv to mimetypes.types_map.  Patch by Geoff
     Wilson.

   - bpo-26709(41): Fixed Y2038 problem in loading binary PLists.

   - bpo-23735(42): Handle terminal resizing with Readline 6.3+ by
     installing our own SIGWINCH handler.  Patch by Eric Price.

   - bpo-26586(43): In http.server, respond with “413 Request header
     fields too large” if there are too many header fields to parse,
     rather than killing the connection and raising an unhandled
     exception.  Patch by Xiang Zhang.

   - bpo-22854(44): Change BufferedReader.writable() and
     BufferedWriter.readable() to always return False.

   - bpo-25195(45): Fix a regression in mock.MagicMock.  _Call is a
     subclass of tuple (changeset 3603bae63c13 only works for classes)
     so we need to implement __ne__ ourselves.  Patch by Andrew Plummer.

   - bpo-26644(46): Raise ValueError rather than SystemError when a
     negative length is passed to SSLSocket.recv() or read().

   - bpo-23804(47): Fix SSL recv(0) and read(0) methods to return zero
     bytes instead of up to 1024.

   - bpo-26616(48): Fixed a bug in datetime.astimezone() method.

   - bpo-21925(49): *note warnings.formatwarning(): 1ba6. now catches
     exceptions on ‘linecache.getline(...)’ to be able to log *note
     ResourceWarning: 244. emitted late during the Python shutdown
     process.

   - bpo-24266(50): Ctrl+C during Readline history search now cancels
     the search mode when compiled with Readline 7.

   - bpo-26560(51): Avoid potential ValueError in
     BaseHandler.start_response.  Initial patch by Peter Inglesby.

   - bpo-26569(52): Fix *note pyclbr.readmodule(): 831. and *note
     pyclbr.readmodule_ex(): 832. to support importing packages.

   - bpo-26499(53): Account for remaining Content-Length in
     HTTPResponse.readline() and read1().  Based on patch by Silent
     Ghost.  Also document that HTTPResponse now supports these methods.

   - bpo-25320(54): Handle sockets in directories unittest discovery is
     scanning.  Patch from Victor van den Elzen.

   - bpo-16181(55): cookiejar.http2time() now returns None if year is
     higher than datetime.MAXYEAR.

   - bpo-26513(56): Fixes platform module detection of Windows Server

   - bpo-23718(57): Fixed parsing time in week 0 before Jan 1.  Original
     patch by Tamás Bence Gedai.

   - bpo-20589(58): Invoking Path.owner() and Path.group() on Windows
     now raise NotImplementedError instead of ImportError.

   - bpo-26177(59): Fixed the keys() method for Canvas and Scrollbar
     widgets.

   - bpo-15068(60): Got rid of excessive buffering in the fileinput
     module.  The bufsize parameter is no longer used.

   - bpo-2202(61): Fix UnboundLocalError in
     AbstractDigestAuthHandler.get_algorithm_impls.  Initial patch by
     Mathieu Dupuy.

   - bpo-25718(62): Fixed pickling and copying the accumulate() iterator
     with total is None.

   - bpo-26475(63): Fixed debugging output for regular expressions with
     the (?x) flag.

   - bpo-26457(64): Fixed the subnets() methods in IP network classes
     for the case when resulting prefix length is equal to maximal
     prefix length.  Based on patch by Xiang Zhang.

   - bpo-26385(65): Remove the file if the internal open() call in
     NamedTemporaryFile() fails.  Patch by Silent Ghost.

   - bpo-26402(66): Fix XML-RPC client to retry when the server shuts
     down a persistent connection.  This was a regression related to the
     new http.client.RemoteDisconnected exception in 3.5.0a4.

   - bpo-25913(67): Leading ‘<~’ is optional now in base64.a85decode()
     with adobe=True.  Patch by Swati Jaiswal.

   - bpo-26186(68): Remove an invalid type check in
     importlib.util.LazyLoader.

   - bpo-26367(69): importlib.__import__() raises SystemError like
     builtins.__import__() when ‘level’ is specified but without an
     accompanying package specified.

   - bpo-26309(70): In the “socketserver” module, shut down the request
     (closing the connected socket) when verify_request() returns false.
     Patch by Aviv Palivoda.

   - bpo-25995(71): os.walk() no longer uses FDs proportional to the
     tree depth.

   - bpo-26117(72): The os.scandir() iterator now closes file descriptor
     not only when the iteration is finished, but when it was failed
     with error.

   - bpo-25911(73): Restored support of bytes paths in os.walk() on
     Windows.

   - bpo-26045(74): Add UTF-8 suggestion to error message when posting a
     non-Latin-1 string with http.client.

   - bpo-12923(75): Reset FancyURLopener’s redirect counter even if
     there is an exception.  Based on patches by Brian Brazil and Daniel
     Rocco.

   - bpo-25945(76): Fixed a crash when unpickle the functools.partial
     object with wrong state.  Fixed a leak in failed functools.partial
     constructor.  “args” and “keywords” attributes of functools.partial
     have now always types tuple and dict correspondingly.

   - bpo-26202(77): copy.deepcopy() now correctly copies range() objects
     with non-atomic attributes.

   - bpo-23076(78): Path.glob() now raises a ValueError if it’s called
     with an invalid pattern.  Patch by Thomas Nyberg.

   - bpo-19883(79): Fixed possible integer overflows in zipimport.

   - bpo-26227(80): On Windows, getnameinfo(), gethostbyaddr() and
     gethostbyname_ex() functions of the socket module now decode the
     hostname from the ANSI code page rather than UTF-8.

   - bpo-26147(81): xmlrpc now works with strings not encodable with
     used non-UTF-8 encoding.

   - bpo-25935(82): Garbage collector now breaks reference loops with
     OrderedDict.

   - bpo-16620(83): Fixed AttributeError in msilib.Directory.glob().

   - bpo-26013(84): Added compatibility with broken protocol 2 pickles
     created in old Python 3 versions (3.4.3 and lower).

   - bpo-25850(85): Use cross-compilation by default for 64-bit Windows.

   - bpo-17633(86): Improve zipimport’s support for namespace packages.

   - bpo-24705(87): Fix sysconfig._parse_makefile not expanding ${} vars
     appearing before $() vars.

   - bpo-22138(88): Fix mock.patch behavior when patching descriptors.
     Restore original values after patching.  Patch contributed by Sean
     McCully.

   - bpo-25672(89): In the ssl module, enable the
     SSL_MODE_RELEASE_BUFFERS mode option if it is safe to do so.

   - bpo-26012(90): Don’t traverse into symlinks for ‘**’ pattern in
     pathlib.Path.[r]glob().

   - bpo-24120(91): Ignore PermissionError when traversing a tree with
     pathlib.Path.[r]glob().  Patch by Ulrich Petri.

   - bpo-25447(92): fileinput now uses sys.stdin as-is if it does not
     have a buffer attribute (restores backward compatibility).

   - bpo-25447(93): Copying the lru_cache() wrapper object now always
     works, independently from the type of the wrapped object (by
     returning the original object unchanged).

   - bpo-24103(94): Fixed possible use after free in
     ElementTree.XMLPullParser.

   - bpo-25860(95): os.fwalk() no longer skips remaining directories
     when error occurs.  Original patch by Samson Lee.

   - bpo-25914(96): Fixed and simplified OrderedDict.__sizeof__.

   - bpo-25902(97): Fixed various refcount issues in ElementTree
     iteration.

   - bpo-25717(98): Restore the previous behaviour of tolerating most
     fstat() errors when opening files.  This was a regression in 3.5a1,
     and stopped anonymous temporary files from working in special
     cases.

   - bpo-24903(99): Fix regression in number of arguments compileall
     accepts when ‘-d’ is specified.  The check on the number of
     arguments has been dropped completely as it never worked correctly
     anyway.

   - bpo-25764(100): In the subprocess module, preserve any exception
     caused by fork() failure when preexec_fn is used.

   - bpo-6478(101): _strptime’s regexp cache now is reset after changing
     timezone with time.tzset().

   - bpo-14285(102): When executing a package with the “python -m
     package” option, and package initialization fails, a proper
     traceback is now reported.  The “runpy” module now lets exceptions
     from package initialization pass back to the caller, rather than
     raising ImportError.

   - bpo-19771(103): Also in runpy and the “-m” option, omit the
     irrelevant message “… is a package and cannot be directly executed”
     if the package could not even be initialized (e.g.  due to a bad
     ‘*.pyc’ file).

   - bpo-25177(104): Fixed problem with the mean of very small and very
     large numbers.  As a side effect, statistics.mean and
     statistics.variance should be significantly faster.

   - bpo-25718(105): Fixed copying object with state with boolean value
     is false.

   - bpo-10131(106): Fixed deep copying of minidom documents.  Based on
     patch by Marian Ganisin.

   - bpo-25725(107): Fixed a reference leak in pickle.loads() when
     unpickling invalid data including tuple instructions.

   - bpo-25663(108): In the Readline completer, avoid listing duplicate
     global names, and search the global namespace before searching
     builtins.

   - bpo-25688(109): Fixed file leak in ElementTree.iterparse() raising
     an error.

   - bpo-23914(110): Fixed SystemError raised by unpickler on broken
     pickle data.

   - bpo-25691(111): Fixed crash on deleting ElementTree.Element
     attributes.

   - bpo-25624(112): ZipFile now always writes a ZIP_STORED header for
     directory entries.  Patch by Dingyuan Wang.

   - Skip getaddrinfo if host is already resolved.  Patch by A. Jesse
     Jiryu Davis.

   - bpo-26050(113): Add asyncio.StreamReader.readuntil() method.  Patch
     by Марк Коренберг.

   - bpo-25924(114): Avoid unnecessary serialization of getaddrinfo(3)
     calls on OS X versions 10.5 or higher.  Original patch by A. Jesse
     Jiryu Davis.

   - bpo-26406(115): Avoid unnecessary serialization of getaddrinfo(3)
     calls on current versions of OpenBSD and NetBSD. Patch by A. Jesse
     Jiryu Davis.

   - bpo-26848(116): Fix asyncio/subprocess.communicate() to handle
     empty input.  Patch by Jack O’Connor.

   - bpo-27040(117): Add loop.get_exception_handler method

   - bpo-27041(118): asyncio: Add loop.create_future method

   - bpo-27223(119): asyncio: Fix _read_ready and _write_ready to
     respect _conn_lost.  Patch by Łukasz Langa.

   - bpo-22970(120): asyncio: Fix inconsistency cancelling
     Condition.wait.  Patch by David Coles.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21386

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20900

   (3) https://peps.python.org/pep-0492/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25738

   (5) https://bugs.python.org/issue?@action=redirect&bpo=21313

   (6) https://bugs.python.org/issue?@action=redirect&bpo=27164

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24291

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26809

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26373

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21776

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27114

   (12) https://bugs.python.org/issue?@action=redirect&bpo=18383

   (13) https://bugs.python.org/issue?@action=redirect&bpo=27057

   (14) https://bugs.python.org/issue?@action=redirect&bpo=27014

   (15) https://bugs.python.org/issue?@action=redirect&bpo=14132

   (16) https://bugs.python.org/issue?@action=redirect&bpo=17214

   (17) https://bugs.python.org/issue?@action=redirect&bpo=26892

   (18) https://bugs.python.org/issue?@action=redirect&bpo=22274

   (19) https://bugs.python.org/issue?@action=redirect&bpo=26807

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25745

   (21) https://bugs.python.org/issue?@action=redirect&bpo=26977

   (22) https://bugs.python.org/issue?@action=redirect&bpo=26881

   (23) https://bugs.python.org/issue?@action=redirect&bpo=23815

   (24) https://bugs.python.org/issue?@action=redirect&bpo=17765

   (25) https://bugs.python.org/issue?@action=redirect&bpo=26873

   (26) https://bugs.python.org/issue?@action=redirect&bpo=26711

   (27) https://bugs.python.org/issue?@action=redirect&bpo=24114

   (28) https://bugs.python.org/issue?@action=redirect&bpo=26864

   (29) https://bugs.python.org/issue?@action=redirect&bpo=26634

   (30) https://bugs.python.org/issue?@action=redirect&bpo=26804

   (31) https://bugs.python.org/issue?@action=redirect&bpo=26837

   (32) https://bugs.python.org/issue?@action=redirect&bpo=26041

   (33) https://bugs.python.org/issue?@action=redirect&bpo=26822

   (34) https://bugs.python.org/issue?@action=redirect&bpo=26733

   (35) https://bugs.python.org/issue?@action=redirect&bpo=26801

   (36) https://bugs.python.org/issue?@action=redirect&bpo=24838

   (37) https://bugs.python.org/issue?@action=redirect&bpo=26717

   (38) https://bugs.python.org/issue?@action=redirect&bpo=26735

   (39) https://bugs.python.org/issue?@action=redirect&bpo=16329

   (40) https://bugs.python.org/issue?@action=redirect&bpo=13952

   (41) https://bugs.python.org/issue?@action=redirect&bpo=26709

   (42) https://bugs.python.org/issue?@action=redirect&bpo=23735

   (43) https://bugs.python.org/issue?@action=redirect&bpo=26586

   (44) https://bugs.python.org/issue?@action=redirect&bpo=22854

   (45) https://bugs.python.org/issue?@action=redirect&bpo=25195

   (46) https://bugs.python.org/issue?@action=redirect&bpo=26644

   (47) https://bugs.python.org/issue?@action=redirect&bpo=23804

   (48) https://bugs.python.org/issue?@action=redirect&bpo=26616

   (49) https://bugs.python.org/issue?@action=redirect&bpo=21925

   (50) https://bugs.python.org/issue?@action=redirect&bpo=24266

   (51) https://bugs.python.org/issue?@action=redirect&bpo=26560

   (52) https://bugs.python.org/issue?@action=redirect&bpo=26569

   (53) https://bugs.python.org/issue?@action=redirect&bpo=26499

   (54) https://bugs.python.org/issue?@action=redirect&bpo=25320

   (55) https://bugs.python.org/issue?@action=redirect&bpo=16181

   (56) https://bugs.python.org/issue?@action=redirect&bpo=26513

   (57) https://bugs.python.org/issue?@action=redirect&bpo=23718

   (58) https://bugs.python.org/issue?@action=redirect&bpo=20589

   (59) https://bugs.python.org/issue?@action=redirect&bpo=26177

   (60) https://bugs.python.org/issue?@action=redirect&bpo=15068

   (61) https://bugs.python.org/issue?@action=redirect&bpo=2202

   (62) https://bugs.python.org/issue?@action=redirect&bpo=25718

   (63) https://bugs.python.org/issue?@action=redirect&bpo=26475

   (64) https://bugs.python.org/issue?@action=redirect&bpo=26457

   (65) https://bugs.python.org/issue?@action=redirect&bpo=26385

   (66) https://bugs.python.org/issue?@action=redirect&bpo=26402

   (67) https://bugs.python.org/issue?@action=redirect&bpo=25913

   (68) https://bugs.python.org/issue?@action=redirect&bpo=26186

   (69) https://bugs.python.org/issue?@action=redirect&bpo=26367

   (70) https://bugs.python.org/issue?@action=redirect&bpo=26309

   (71) https://bugs.python.org/issue?@action=redirect&bpo=25995

   (72) https://bugs.python.org/issue?@action=redirect&bpo=26117

   (73) https://bugs.python.org/issue?@action=redirect&bpo=25911

   (74) https://bugs.python.org/issue?@action=redirect&bpo=26045

   (75) https://bugs.python.org/issue?@action=redirect&bpo=12923

   (76) https://bugs.python.org/issue?@action=redirect&bpo=25945

   (77) https://bugs.python.org/issue?@action=redirect&bpo=26202

   (78) https://bugs.python.org/issue?@action=redirect&bpo=23076

   (79) https://bugs.python.org/issue?@action=redirect&bpo=19883

   (80) https://bugs.python.org/issue?@action=redirect&bpo=26227

   (81) https://bugs.python.org/issue?@action=redirect&bpo=26147

   (82) https://bugs.python.org/issue?@action=redirect&bpo=25935

   (83) https://bugs.python.org/issue?@action=redirect&bpo=16620

   (84) https://bugs.python.org/issue?@action=redirect&bpo=26013

   (85) https://bugs.python.org/issue?@action=redirect&bpo=25850

   (86) https://bugs.python.org/issue?@action=redirect&bpo=17633

   (87) https://bugs.python.org/issue?@action=redirect&bpo=24705

   (88) https://bugs.python.org/issue?@action=redirect&bpo=22138

   (89) https://bugs.python.org/issue?@action=redirect&bpo=25672

   (90) https://bugs.python.org/issue?@action=redirect&bpo=26012

   (91) https://bugs.python.org/issue?@action=redirect&bpo=24120

   (92) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (93) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (94) https://bugs.python.org/issue?@action=redirect&bpo=24103

   (95) https://bugs.python.org/issue?@action=redirect&bpo=25860

   (96) https://bugs.python.org/issue?@action=redirect&bpo=25914

   (97) https://bugs.python.org/issue?@action=redirect&bpo=25902

   (98) https://bugs.python.org/issue?@action=redirect&bpo=25717

   (99) https://bugs.python.org/issue?@action=redirect&bpo=24903

   (100) https://bugs.python.org/issue?@action=redirect&bpo=25764

   (101) https://bugs.python.org/issue?@action=redirect&bpo=6478

   (102) https://bugs.python.org/issue?@action=redirect&bpo=14285

   (103) https://bugs.python.org/issue?@action=redirect&bpo=19771

   (104) https://bugs.python.org/issue?@action=redirect&bpo=25177

   (105) https://bugs.python.org/issue?@action=redirect&bpo=25718

   (106) https://bugs.python.org/issue?@action=redirect&bpo=10131

   (107) https://bugs.python.org/issue?@action=redirect&bpo=25725

   (108) https://bugs.python.org/issue?@action=redirect&bpo=25663

   (109) https://bugs.python.org/issue?@action=redirect&bpo=25688

   (110) https://bugs.python.org/issue?@action=redirect&bpo=23914

   (111) https://bugs.python.org/issue?@action=redirect&bpo=25691

   (112) https://bugs.python.org/issue?@action=redirect&bpo=25624

   (113) https://bugs.python.org/issue?@action=redirect&bpo=26050

   (114) https://bugs.python.org/issue?@action=redirect&bpo=25924

   (115) https://bugs.python.org/issue?@action=redirect&bpo=26406

   (116) https://bugs.python.org/issue?@action=redirect&bpo=26848

   (117) https://bugs.python.org/issue?@action=redirect&bpo=27040

   (118) https://bugs.python.org/issue?@action=redirect&bpo=27041

   (119) https://bugs.python.org/issue?@action=redirect&bpo=27223

   (120) https://bugs.python.org/issue?@action=redirect&bpo=22970


File: python.info,  Node: IDLE<63>,  Next: Documentation<78>,  Prev: Library<170>,  Up: Python 3 5 2 release candidate 1

1.23.106.4 IDLE
...............

   - bpo-5124(1): Paste with text selected now replaces the selection on
     X11.  This matches how paste works on Windows, Mac, most modern
     Linux apps, and ttk widgets.  Original patch by Serhiy Storchaka.

   - bpo-24759(2): Make clear in idlelib.idle_test.__init__ that the
     directory is a private implementation of test.test_idle and tool
     for maintainers.

   - bpo-27196(3): Stop ‘ThemeChanged’ warnings when running IDLE tests.
     These persisted after other warnings were suppressed in #20567.
     Apply Serhiy Storchaka’s update_idletasks solution to four test
     files.  Record this additional advice in idle_test/README.txt

   - bpo-20567(4): Revise idle_test/README.txt with advice about
     avoiding tk warning messages from tests.  Apply advice to several
     IDLE tests.

   - bpo-27117(5): Make colorizer htest and turtledemo work with dark
     themes.  Move code for configuring text widget colors to a new
     function.

   - bpo-26673(6): When tk reports font size as 0, change to size 10.
     Such fonts on Linux prevented the configuration dialog from
     opening.

   - bpo-21939(7): Add test for IDLE’s percolator.  Original patch by
     Saimadhav Heblikar.

   - bpo-21676(8): Add test for IDLE’s replace dialog.  Original patch
     by Saimadhav Heblikar.

   - bpo-18410(9): Add test for IDLE’s search dialog.  Original patch by
     Westley Martínez.

   - bpo-21703(10): Add test for IDLE’s undo delegator.  Original patch
     by Saimadhav Heblikar .

   - bpo-27044(11): Add ConfigDialog.remove_var_callbacks to stop memory
     leaks.

   - bpo-23977(12): Add more asserts to test_delegator.

   - bpo-20640(13): Add tests for idlelib.configHelpSourceEdit.  Patch
     by Saimadhav Heblikar.

   - In the ‘IDLE-console differences’ section of the IDLE doc, clarify
     how running with IDLE affects sys.modules and the standard streams.

   - bpo-25507(14): fix incorrect change in IOBinding that prevented
     printing.  Augment IOBinding htest to include all major IOBinding
     functions.

   - bpo-25905(15): Revert unwanted conversion of ‘ to ’ RIGHT SINGLE
     QUOTATION MARK in README.txt and open this and NEWS.txt with
     ‘ascii’.  Re-encode CREDITS.txt to utf-8 and open it with ‘utf-8’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5124

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24759

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27196

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20567

   (5) https://bugs.python.org/issue?@action=redirect&bpo=27117

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26673

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21939

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21676

   (9) https://bugs.python.org/issue?@action=redirect&bpo=18410

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21703

   (11) https://bugs.python.org/issue?@action=redirect&bpo=27044

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23977

   (13) https://bugs.python.org/issue?@action=redirect&bpo=20640

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25507

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25905


File: python.info,  Node: Documentation<78>,  Next: Tests<83>,  Prev: IDLE<63>,  Up: Python 3 5 2 release candidate 1

1.23.106.5 Documentation
........................

   - bpo-19489(1): Moved the search box from the sidebar to the header
     and footer of each page.  Patch by Ammar Askar.

   - bpo-24136(2): Document the new PEP 448(3) unpacking syntax of 3.5.

   - bpo-26736(4): Used HTTPS for external links in the documentation if
     possible.

   - bpo-6953(5): Rework the Readline module documentation to group
     related functions together, and add more details such as what
     underlying Readline functions and variables are accessed.

   - bpo-23606(6): Adds note to ctypes documentation regarding
     cdll.msvcrt.

   - bpo-25500(7): Fix documentation to not claim that __import__ is
     searched for in the global scope.

   - bpo-26014(8): Update 3.x packaging documentation: * “See also”
     links to the new docs are now provided in the legacy pages * links
     to setuptools documentation have been updated

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19489

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24136

   (3) https://peps.python.org/pep-0448/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26736

   (5) https://bugs.python.org/issue?@action=redirect&bpo=6953

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23606

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25500

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26014


File: python.info,  Node: Tests<83>,  Next: Build<90>,  Prev: Documentation<78>,  Up: Python 3 5 2 release candidate 1

1.23.106.6 Tests
................

   - bpo-21916(1): Added tests for the turtle module.  Patch by ingrid,
     Gregory Loyse and Jelle Zijlstra.

   - bpo-26523(2): The multiprocessing thread pool
     (multiprocessing.dummy.Pool) was untested.

   - bpo-26015(3): Added new tests for pickling iterators of mutable
     sequences.

   - bpo-26325(4): Added test.support.check_no_resource_warning() to
     check that no ResourceWarning is emitted.

   - bpo-25940(5): Changed test_ssl to use self-signed.pythontest.net.
     This avoids relying on svn.python.org, which recently changed root
     certificate.

   - bpo-25616(6): Tests for OrderedDict are extracted from
     test_collections into separate file test_ordered_dict.

   - bpo-26583(7): Skip test_timestamp_overflow in test_import if
     bytecode files cannot be written.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21916

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26523

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26015

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26325

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25940

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25616

   (7) https://bugs.python.org/issue?@action=redirect&bpo=26583


File: python.info,  Node: Build<90>,  Next: Windows<77>,  Prev: Tests<83>,  Up: Python 3 5 2 release candidate 1

1.23.106.7 Build
................

   - bpo-26884(1): Fix linking extension modules for cross builds.
     Patch by Xavier de Gaye.

   - bpo-22359(2): Disable the rules for running _freeze_importlib and
     pgen when cross-compiling.  The output of these programs is
     normally saved with the source code anyway, and is still
     regenerated when doing a native build.  Patch by Xavier de Gaye.

   - bpo-27229(3): Fix the cross-compiling pgen rule for in-tree builds.
     Patch by Xavier de Gaye.

   - bpo-21668(4): Link audioop, _datetime, _ctypes_test modules to
     libm, except on Mac OS X. Patch written by Xavier de Gaye.

   - bpo-25702(5): A –with-lto configure option has been added that will
     enable link time optimizations at build time during a make
     profile-opt.  Some compilers and toolchains are known to not
     produce stable code when using LTO, be sure to test things
     thoroughly before relying on it.  It can provide a few % speed up
     over profile-opt alone.

   - bpo-26624(6): Adds validation of ucrtbase[d].dll version with
     warning for old versions.

   - bpo-17603(7): Avoid error about nonexistent fileblocks.o file by
     using a lower-level check for st_blocks in struct stat.

   - bpo-26079(8): Fixing the build output folder for tix-8.4.3.6.
     Patch by Bjoern Thiel.

   - bpo-26465(9): Update Windows builds to use OpenSSL 1.0.2g.

   - bpo-24421(10): Compile Modules/_math.c once, before building
     extensions.  Previously it could fail to compile properly if the
     math and cmath builds were concurrent.

   - bpo-25348(11): Added ‘--pgo’ and ‘--pgo-job’ arguments to
     ‘PCbuild\build.bat’ for building with Profile-Guided Optimization.
     The old ‘PCbuild\build_pgo.bat’ script is now deprecated, and
     simply calls ‘PCbuild\build.bat --pgo %*’.

   - bpo-25827(12): Add support for building with ICC to ‘configure’,
     including a new ‘--with-icc’ flag.

   - bpo-25696(13): Fix installation of Python on UNIX with make -j9.

   - bpo-26930(14): Update OS X 10.5+ 32-bit-only installer to build and
     link with OpenSSL 1.0.2h.

   - bpo-26268(15): Update Windows builds to use OpenSSL 1.0.2f.

   - bpo-25136(16): Support Apple Xcode 7’s new textual SDK stub
     libraries.

   - bpo-24324(17): Do not enable unreachable code warnings when using
     gcc as the option does not work correctly in older versions of gcc
     and has been silently removed as of gcc-4.5.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26884

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22359

   (3) https://bugs.python.org/issue?@action=redirect&bpo=27229

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21668

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25702

   (6) https://bugs.python.org/issue?@action=redirect&bpo=26624

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17603

   (8) https://bugs.python.org/issue?@action=redirect&bpo=26079

   (9) https://bugs.python.org/issue?@action=redirect&bpo=26465

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24421

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25348

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25827

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25696

   (14) https://bugs.python.org/issue?@action=redirect&bpo=26930

   (15) https://bugs.python.org/issue?@action=redirect&bpo=26268

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25136

   (17) https://bugs.python.org/issue?@action=redirect&bpo=24324


File: python.info,  Node: Windows<77>,  Next: Tools/Demos<49>,  Prev: Build<90>,  Up: Python 3 5 2 release candidate 1

1.23.106.8 Windows
..................

   - bpo-27053(1): Updates make_zip.py to correctly generate library ZIP
     file.

   - bpo-26268(2): Update the prepare_ssl.py script to handle OpenSSL
     releases that don’t include the contents of the include directory
     (that is, 1.0.2e and later).

   - bpo-26071(3): bdist_wininst created binaries fail to start and find
     32bit Python

   - bpo-26073(4): Update the list of magic numbers in launcher

   - bpo-26065(5): Excludes venv from library when generating embeddable
     distro.

   - bpo-17500(6): Remove unused and outdated icons.  (See also:
     ‘https://github.com/python/pythondotorg/issues/945’)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=27053

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26268

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26071

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26073

   (5) https://bugs.python.org/issue?@action=redirect&bpo=26065

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17500


File: python.info,  Node: Tools/Demos<49>,  Prev: Windows<77>,  Up: Python 3 5 2 release candidate 1

1.23.106.9 Tools/Demos
......................

   - bpo-26799(1): Fix python-gdb.py: don’t get C types once when the
     Python code is loaded, but get C types on demand.  The C types can
     change if python-gdb.py is loaded before the Python executable.
     Patch written by Thomas Ilsche.

   - bpo-26271(2): Fix the Freeze tool to properly use flags passed
     through configure.  Patch by Daniel Shaulov.

   - bpo-26489(3): Add dictionary unpacking support to
     Tools/parser/unparse.py.  Patch by Guo Ci Teo.

   - bpo-26316(4): Fix variable name typo in Argument Clinic.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=26799

   (2) https://bugs.python.org/issue?@action=redirect&bpo=26271

   (3) https://bugs.python.org/issue?@action=redirect&bpo=26489

   (4) https://bugs.python.org/issue?@action=redirect&bpo=26316


File: python.info,  Node: Python 3 5 1 final,  Next: Python 3 5 1 release candidate 1,  Prev: Python 3 5 2 release candidate 1,  Up: Changelog

1.23.107 Python 3.5.1 final
---------------------------

'Release date: 2015-12-06'

* Menu:

* Core and Builtins: Core and Builtins<169>.
* Windows: Windows<78>.


File: python.info,  Node: Core and Builtins<169>,  Next: Windows<78>,  Up: Python 3 5 1 final

1.23.107.1 Core and Builtins
............................

   - bpo-25709(1): Fixed problem with in-place string concatenation and
     utf-8 cache.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25709


File: python.info,  Node: Windows<78>,  Prev: Core and Builtins<169>,  Up: Python 3 5 1 final

1.23.107.2 Windows
..................

   - bpo-25715(1): Python 3.5.1 installer shows wrong upgrade path and
     incorrect logic for launcher detection.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25715


File: python.info,  Node: Python 3 5 1 release candidate 1,  Next: Python 3 5 0 final,  Prev: Python 3 5 1 final,  Up: Changelog

1.23.108 Python 3.5.1 release candidate 1
-----------------------------------------

'Release date: 2015-11-22'

* Menu:

* Core and Builtins: Core and Builtins<170>.
* Library: Library<171>.
* IDLE: IDLE<64>.
* Documentation: Documentation<79>.
* Tests: Tests<84>.
* Build: Build<91>.
* Windows: Windows<79>.
* Tools/Demos: Tools/Demos<50>.


File: python.info,  Node: Core and Builtins<170>,  Next: Library<171>,  Up: Python 3 5 1 release candidate 1

1.23.108.1 Core and Builtins
............................

   - bpo-25630(1): Fix a possible segfault during argument parsing in
     functions that accept filesystem paths.

   - bpo-23564(2): Fixed a partially broken sanity check in the
     _posixsubprocess internals regarding how fds_to_pass were passed to
     the child.  The bug had no actual impact as subprocess.py already
     avoided it.

   - bpo-25388(3): Fixed tokenizer crash when processing undecodable
     source code with a null byte.

   - bpo-25462(4): The hash of the key now is calculated only once in
     most operations in C implementation of OrderedDict.

   - bpo-22995(5): Default implementation of __reduce__ and
     __reduce_ex__ now rejects builtin types with not defined __new__.

   - bpo-25555(6): Fix parser and AST: fill lineno and col_offset of
     “arg” node when compiling AST from Python objects.

   - bpo-24802(7): Avoid buffer overreads when int(), float(),
     compile(), exec() and eval() are passed bytes-like objects.  These
     objects are not necessarily terminated by a null byte, but the
     functions assumed they were.

   - bpo-24726(8): Fixed a crash and leaking NULL in repr() of
     OrderedDict that was mutated by direct calls of dict methods.

   - bpo-25449(9): Iterating OrderedDict with keys with unstable hash
     now raises KeyError in C implementations as well as in Python
     implementation.

   - bpo-25395(10): Fixed crash when highly nested OrderedDict
     structures were garbage collected.

   - bpo-25274(11): sys.setrecursionlimit() now raises a RecursionError
     if the new recursion limit is too low depending at the current
     recursion depth.  Modify also the “lower-water mark” formula to
     make it monotonic.  This mark is used to decide when the overflowed
     flag of the thread state is reset.

   - bpo-24402(12): Fix input() to prompt to the redirected stdout when
     sys.stdout.fileno() fails.

   - bpo-24806(13): Prevent builtin types that are not allowed to be
     subclassed from being subclassed through multiple inheritance.

   - bpo-24848(14): Fixed a number of bugs in UTF-7 decoding of
     misformed data.

   - bpo-25280(15): Import trace messages emitted in verbose (-v) mode
     are no longer formatted twice.

   - bpo-25003(16): On Solaris 11.3 or newer, os.urandom() now uses the
     getrandom() function instead of the getentropy() function.  The
     getentropy() function is blocking to generate very good quality
     entropy, os.urandom() doesn’t need such high-quality entropy.

   - bpo-25182(17): The stdprinter (used as sys.stderr before the io
     module is imported at startup) now uses the backslashreplace error
     handler.

   - bpo-25131(18): Make the line number and column offset of set/dict
     literals and comprehensions correspond to the opening brace.

   - bpo-25150(19): Hide the private ‘_Py_atomic_XXX’ symbols from the
     public Python.h header to fix a compilation error with OpenMP.
     PyThreadState_GET() becomes an alias to PyThreadState_Get() to
     avoid ABI incompatibilities.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25630

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23564

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25388

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25462

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22995

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25555

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24802

   (8) https://bugs.python.org/issue?@action=redirect&bpo=24726

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25449

   (10) https://bugs.python.org/issue?@action=redirect&bpo=25395

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25274

   (12) https://bugs.python.org/issue?@action=redirect&bpo=24402

   (13) https://bugs.python.org/issue?@action=redirect&bpo=24806

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24848

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25280

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25003

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25182

   (18) https://bugs.python.org/issue?@action=redirect&bpo=25131

   (19) https://bugs.python.org/issue?@action=redirect&bpo=25150


File: python.info,  Node: Library<171>,  Next: IDLE<64>,  Prev: Core and Builtins<170>,  Up: Python 3 5 1 release candidate 1

1.23.108.2 Library
..................

   - bpo-25626(1): Change three zlib functions to accept sizes that fit
     in Py_ssize_t, but internally cap those sizes to UINT_MAX. This
     resolves a regression in 3.5 where GzipFile.read() failed to read
     chunks larger than 2 or 4 GiB. The change affects the
     zlib.Decompress.decompress() max_length parameter, the
     zlib.decompress() bufsize parameter, and the
     zlib.Decompress.flush() length parameter.

   - bpo-25583(2): Avoid incorrect errors raised by
     os.makedirs(exist_ok=True) when the OS gives priority to errors
     such as EACCES over EEXIST.

   - bpo-25593(3): Change semantics of EventLoop.stop() in asyncio.

   - bpo-6973(4): When we know a subprocess.Popen process has died, do
     not allow the send_signal(), terminate(), or kill() methods to do
     anything as they could potentially signal a different process.

   - bpo-25590(5): In the Readline completer, only call getattr() once
     per attribute.

   - bpo-25498(6): Fix a crash when garbage-collecting ctypes objects
     created by wrapping a memoryview.  This was a regression made in
     3.5a1.  Based on patch by Eryksun.

   - bpo-25584(7): Added “escape” to the __all__ list in the glob
     module.

   - bpo-25584(8): Fixed recursive glob() with patterns starting with
     ‘**’.

   - bpo-25446(9): Fix regression in smtplib’s AUTH LOGIN support.

   - bpo-18010(10): Fix the pydoc web server’s module search function to
     handle exceptions from importing packages.

   - bpo-25554(11): Got rid of circular references in regular expression
     parsing.

   - bpo-25510(12): fileinput.FileInput.readline() now returns b’’
     instead of ‘’ at the end if the FileInput was opened with binary
     mode.  Patch by Ryosuke Ito.

   - bpo-25503(13): Fixed inspect.getdoc() for inherited docstrings of
     properties.  Original patch by John Mark Vandenberg.

   - bpo-25515(14): Always use os.urandom as a source of randomness in
     uuid.uuid4.

   - bpo-21827(15): Fixed textwrap.dedent() for the case when largest
     common whitespace is a substring of smallest leading whitespace.
     Based on patch by Robert Li.

   - bpo-25447(16): The lru_cache() wrapper objects now can be copied
     and pickled (by returning the original object unchanged).

   - bpo-25390(17): typing: Don’t crash on Union[str, Pattern].

   - bpo-25441(18): asyncio: Raise error from drain() when socket is
     closed.

   - bpo-25410(19): Cleaned up and fixed minor bugs in C implementation
     of OrderedDict.

   - bpo-25411(20): Improved Unicode support in SMTPHandler through
     better use of the email package.  Thanks to user simon04 for the
     patch.

   - bpo-25407(21): Remove mentions of the formatter module being
     removed in Python 3.6.

   - bpo-25406(22): Fixed a bug in C implementation of
     OrderedDict.move_to_end() that caused segmentation fault or hang in
     iterating after moving several items to the start of ordered dict.

   - bpo-25364(23): zipfile now works in threads disabled builds.

   - bpo-25328(24): smtpd’s SMTPChannel now correctly raises a
     ValueError if both decode_data and enable_SMTPUTF8 are set to true.

   - bpo-25316(25): distutils raises OSError instead of
     DistutilsPlatformError when MSVC is not installed.

   - bpo-25380(26): Fixed protocol for the STACK_GLOBAL opcode in
     pickletools.opcodes.

   - bpo-23972(27): Updates asyncio datagram create method allowing
     reuseport and reuseaddr socket options to be set prior to binding
     the socket.  Mirroring the existing asyncio create_server method
     the reuseaddr option for datagram sockets defaults to True if the
     O/S is ‘posix’ (except if the platform is Cygwin).  Patch by Chris
     Laws.

   - bpo-25304(28): Add asyncio.run_coroutine_threadsafe().  This lets
     you submit a coroutine to a loop from another thread, returning a
     concurrent.futures.Future.  By Vincent Michel.

   - bpo-25232(29): Fix CGIRequestHandler to split the query from the
     URL at the first question mark (?)  rather than the last.  Patch
     from Xiang Zhang.

   - bpo-24657(30): Prevent CGIRequestHandler from collapsing slashes in
     the query part of the URL as if it were a path.  Patch from Xiang
     Zhang.

   - bpo-24483(31): C implementation of functools.lru_cache() now
     calculates key’s hash only once.

   - bpo-22958(32): Constructor and update method of
     weakref.WeakValueDictionary now accept the self and the dict
     keyword arguments.

   - bpo-22609(33): Constructor of collections.UserDict now accepts the
     self keyword argument.

   - bpo-25111(34): Fixed comparison of traceback.FrameSummary.

   - bpo-25262(35): Added support for BINBYTES8 opcode in Python
     implementation of unpickler.  Highest 32 bits of 64-bit size for
     BINUNICODE8 and BINBYTES8 opcodes no longer silently ignored on
     32-bit platforms in C implementation.

   - bpo-25034(36): Fix string.Formatter problem with auto-numbering and
     nested format_specs.  Patch by Anthon van der Neut.

   - bpo-25233(37): Rewrite the guts of asyncio.Queue and
     asyncio.Semaphore to be more understandable and correct.

   - bpo-25203(38): Failed readline.set_completer_delims() no longer
     left the module in inconsistent state.

   - bpo-23600(39): Default implementation of tzinfo.fromutc() was
     returning wrong results in some cases.

   - bpo-23329(40): Allow the ssl module to be built with older versions
     of LibreSSL.

   - Prevent overflow in _Unpickler_Read.

   - bpo-25047(41): The XML encoding declaration written by Element Tree
     now respects the letter case given by the user.  This restores the
     ability to write encoding names in uppercase like “UTF-8”, which
     worked in Python 2.

   - bpo-25135(42): Make deque_clear() safer by emptying the deque
     before clearing.  This helps avoid possible reentrancy issues.

   - bpo-19143(43): platform module now reads Windows version from
     kernel32.dll to avoid compatibility shims.

   - bpo-25092(44): Fix datetime.strftime() failure when errno was
     already set to EINVAL.

   - bpo-23517(45): Fix rounding in fromtimestamp() and
     utcfromtimestamp() methods of datetime.datetime: microseconds are
     now rounded to nearest with ties going to nearest even integer
     (ROUND_HALF_EVEN), instead of being rounding towards minus infinity
     (ROUND_FLOOR). It’s important that these methods use the same
     rounding mode than datetime.timedelta to keep the property:
     (datetime(1970,1,1) + timedelta(seconds=t)) ==
     datetime.utcfromtimestamp(t).  It also the rounding mode used by
     round(float) for example.

   - bpo-25155(46): Fix datetime.datetime.now() and
     datetime.datetime.utcnow() on Windows to support date after year
     2038.  It was a regression introduced in Python 3.5.0.

   - bpo-25108(47): Omitted internal frames in traceback functions
     print_stack(), format_stack(), and extract_stack() called without
     arguments.

   - bpo-25118(48): Fix a regression of Python 3.5.0 in os.waitpid() on
     Windows.

   - bpo-24684(49): socket.socket.getaddrinfo() now calls
     PyUnicode_AsEncodedString() instead of calling the encode() method
     of the host, to handle correctly custom string with an encode()
     method which doesn’t return a byte string.  The encoder of the IDNA
     codec is now called directly instead of calling the encode() method
     of the string.

   - bpo-25060(50): Correctly compute stack usage of the BUILD_MAP
     opcode.

   - bpo-24857(51): Comparing call_args to a long sequence now correctly
     returns a boolean result instead of raising an exception.  Patch by
     A Kaptur.

   - bpo-23144(52): Make sure that HTMLParser.feed() returns all the
     data, even when convert_charrefs is True.

   - bpo-24982(53): shutil.make_archive() with the “zip” format now adds
     entries for directories (including empty directories) in ZIP file.

   - bpo-25019(54): Fixed a crash caused by setting non-string key of
     expat parser.  Based on patch by John Leitch.

   - bpo-16180(55): Exit pdb if file has syntax error, instead of
     trapping user in an infinite loop.  Patch by Xavier de Gaye.

   - bpo-24891(56): Fix a race condition at Python startup if the file
     descriptor of stdin (0), stdout (1) or stderr (2) is closed while
     Python is creating sys.stdin, sys.stdout and sys.stderr objects.
     These attributes are now set to None if the creation of the object
     failed, instead of raising an OSError exception.  Initial patch
     written by Marco Paolini.

   - bpo-24992(57): Fix error handling and a race condition (related to
     garbage collection) in collections.OrderedDict constructor.

   - bpo-24881(58): Fixed setting binary mode in Python implementation
     of FileIO on Windows and Cygwin.  Patch from Akira Li.

   - bpo-25578(59): Fix (another) memory leak in SSLSocket.getpeercer().

   - bpo-25530(60): Disable the vulnerable SSLv3 protocol by default
     when creating ssl.SSLContext.

   - bpo-25569(61): Fix memory leak in SSLSocket.getpeercert().

   - bpo-25471(62): Sockets returned from accept() shouldn’t appear to
     be nonblocking.

   - bpo-25319(63): When threading.Event is reinitialized, the
     underlying condition should use a regular lock rather than a
     recursive lock.

   - bpo-21112(64): Fix regression in unittest.expectedFailure on
     subclasses.  Patch from Berker Peksag.

   - bpo-24764(65): cgi.FieldStorage.read_multi() now ignores the
     Content-Length header in part headers.  Patch written by Peter
     Landry and reviewed by Pierre Quentel.

   - bpo-24913(66): Fix overrun error in deque.index().  Found by John
     Leitch and Bryce Darling.

   - bpo-24774(67): Fix docstring in http.server.test.  Patch from
     Chiu-Hsiang Hsu.

   - bpo-21159(68): Improve message in
     configparser.InterpolationMissingOptionError.  Patch from Łukasz
     Langa.

   - bpo-20362(69): Honour TestCase.longMessage correctly in
     assertRegex.  Patch from Ilia Kurenkov.

   - bpo-23572(70): Fixed functools.singledispatch on classes with false
     metaclasses.  Patch by Ethan Furman.

   - asyncio: ensure_future() now accepts awaitable objects.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25626

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25583

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25593

   (4) https://bugs.python.org/issue?@action=redirect&bpo=6973

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25590

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25498

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25584

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25584

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25446

   (10) https://bugs.python.org/issue?@action=redirect&bpo=18010

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25554

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25510

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25503

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25515

   (15) https://bugs.python.org/issue?@action=redirect&bpo=21827

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25447

   (17) https://bugs.python.org/issue?@action=redirect&bpo=25390

   (18) https://bugs.python.org/issue?@action=redirect&bpo=25441

   (19) https://bugs.python.org/issue?@action=redirect&bpo=25410

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25411

   (21) https://bugs.python.org/issue?@action=redirect&bpo=25407

   (22) https://bugs.python.org/issue?@action=redirect&bpo=25406

   (23) https://bugs.python.org/issue?@action=redirect&bpo=25364

   (24) https://bugs.python.org/issue?@action=redirect&bpo=25328

   (25) https://bugs.python.org/issue?@action=redirect&bpo=25316

   (26) https://bugs.python.org/issue?@action=redirect&bpo=25380

   (27) https://bugs.python.org/issue?@action=redirect&bpo=23972

   (28) https://bugs.python.org/issue?@action=redirect&bpo=25304

   (29) https://bugs.python.org/issue?@action=redirect&bpo=25232

   (30) https://bugs.python.org/issue?@action=redirect&bpo=24657

   (31) https://bugs.python.org/issue?@action=redirect&bpo=24483

   (32) https://bugs.python.org/issue?@action=redirect&bpo=22958

   (33) https://bugs.python.org/issue?@action=redirect&bpo=22609

   (34) https://bugs.python.org/issue?@action=redirect&bpo=25111

   (35) https://bugs.python.org/issue?@action=redirect&bpo=25262

   (36) https://bugs.python.org/issue?@action=redirect&bpo=25034

   (37) https://bugs.python.org/issue?@action=redirect&bpo=25233

   (38) https://bugs.python.org/issue?@action=redirect&bpo=25203

   (39) https://bugs.python.org/issue?@action=redirect&bpo=23600

   (40) https://bugs.python.org/issue?@action=redirect&bpo=23329

   (41) https://bugs.python.org/issue?@action=redirect&bpo=25047

   (42) https://bugs.python.org/issue?@action=redirect&bpo=25135

   (43) https://bugs.python.org/issue?@action=redirect&bpo=19143

   (44) https://bugs.python.org/issue?@action=redirect&bpo=25092

   (45) https://bugs.python.org/issue?@action=redirect&bpo=23517

   (46) https://bugs.python.org/issue?@action=redirect&bpo=25155

   (47) https://bugs.python.org/issue?@action=redirect&bpo=25108

   (48) https://bugs.python.org/issue?@action=redirect&bpo=25118

   (49) https://bugs.python.org/issue?@action=redirect&bpo=24684

   (50) https://bugs.python.org/issue?@action=redirect&bpo=25060

   (51) https://bugs.python.org/issue?@action=redirect&bpo=24857

   (52) https://bugs.python.org/issue?@action=redirect&bpo=23144

   (53) https://bugs.python.org/issue?@action=redirect&bpo=24982

   (54) https://bugs.python.org/issue?@action=redirect&bpo=25019

   (55) https://bugs.python.org/issue?@action=redirect&bpo=16180

   (56) https://bugs.python.org/issue?@action=redirect&bpo=24891

   (57) https://bugs.python.org/issue?@action=redirect&bpo=24992

   (58) https://bugs.python.org/issue?@action=redirect&bpo=24881

   (59) https://bugs.python.org/issue?@action=redirect&bpo=25578

   (60) https://bugs.python.org/issue?@action=redirect&bpo=25530

   (61) https://bugs.python.org/issue?@action=redirect&bpo=25569

   (62) https://bugs.python.org/issue?@action=redirect&bpo=25471

   (63) https://bugs.python.org/issue?@action=redirect&bpo=25319

   (64) https://bugs.python.org/issue?@action=redirect&bpo=21112

   (65) https://bugs.python.org/issue?@action=redirect&bpo=24764

   (66) https://bugs.python.org/issue?@action=redirect&bpo=24913

   (67) https://bugs.python.org/issue?@action=redirect&bpo=24774

   (68) https://bugs.python.org/issue?@action=redirect&bpo=21159

   (69) https://bugs.python.org/issue?@action=redirect&bpo=20362

   (70) https://bugs.python.org/issue?@action=redirect&bpo=23572


File: python.info,  Node: IDLE<64>,  Next: Documentation<79>,  Prev: Library<171>,  Up: Python 3 5 1 release candidate 1

1.23.108.3 IDLE
...............

   - bpo-15348(1): Stop the debugger engine (normally in a user process)
     before closing the debugger window (running in the IDLE process).
     This prevents the RuntimeErrors that were being caught and ignored.

   - bpo-24455(2): Prevent IDLE from hanging when a) closing the shell
     while the debugger is active (15347); b) closing the debugger with
     the [X] button (15348); and c) activating the debugger when already
     active (24455).  The patch by Mark Roseman does this by making two
     changes.  1.  Suspend and resume the gui.interaction method with
     the tcl vwait mechanism intended for this purpose (instead of
     root.mainloop & .quit).  2.  In gui.run, allow any existing
     interaction to terminate first.

   - Change ‘The program’ to ‘Your program’ in an IDLE ‘kill program?’
     message to make it clearer that the program referred to is the
     currently running user program, not IDLE itself.

   - bpo-24750(3): Improve the appearance of the IDLE editor window
     status bar.  Patch by Mark Roseman.

   - bpo-25313(4): Change the handling of new built-in text color themes
     to better address the compatibility problem introduced by the
     addition of IDLE Dark.  Consistently use the revised
     idleConf.CurrentTheme everywhere in idlelib.

   - bpo-24782(5): Extension configuration is now a tab in the IDLE
     Preferences dialog rather than a separate dialog.  The former tabs
     are now a sorted list.  Patch by Mark Roseman.

   - bpo-22726(6): Re-activate the config dialog help button with some
     content about the other buttons and the new IDLE Dark theme.

   - bpo-24820(7): IDLE now has an ‘IDLE Dark’ built-in text color
     theme.  It is more or less IDLE Classic inverted, with a cobalt
     blue background.  Strings, comments, keywords, … are still green,
     red, orange, … .  To use it with IDLEs released before November
     2015, hit the ‘Save as New Custom Theme’ button and enter a new
     name, such as ‘Custom Dark’.  The custom theme will work with any
     IDLE release, and can be modified.

   - bpo-25224(8): README.txt is now an idlelib index for IDLE
     developers and curious users.  The previous user content is now in
     the IDLE doc chapter.  ‘IDLE’ now means ‘Integrated Development and
     Learning Environment’.

   - bpo-24820(9): Users can now set breakpoint colors in Settings ->
     Custom Highlighting.  Original patch by Mark Roseman.

   - bpo-24972(10): Inactive selection background now matches active
     selection background, as configured by users, on all systems.
     Found items are now always highlighted on Windows.  Initial patch
     by Mark Roseman.

   - bpo-24570(11): Idle: make calltip and completion boxes appear on
     Macs affected by a tk regression.  Initial patch by Mark Roseman.

   - bpo-24988(12): Idle ScrolledList context menus (used in debugger)
     now work on Mac Aqua.  Patch by Mark Roseman.

   - bpo-24801(13): Make right-click for context menu work on Mac Aqua.
     Patch by Mark Roseman.

   - bpo-25173(14): Associate tkinter messageboxes with a specific
     widget.  For Mac OSX, make them a ‘sheet’.  Patch by Mark Roseman.

   - bpo-25198(15): Enhance the initial html viewer now used for Idle
     Help.  Properly indent fixed-pitch text (patch by Mark Roseman).
     Give code snippet a very Sphinx-like light blueish-gray background.
     Re-use initial width and height set by users for shell and editor.
     When the Table of Contents (TOC) menu is used, put the section
     header at the top of the screen.

   - bpo-25225(16): Condense and rewrite Idle doc section on text
     colors.

   - bpo-21995(17): Explain some differences between IDLE and console
     Python.

   - bpo-22820(18): Explain need for 'print' when running file from Idle
     editor.

   - bpo-25224(19): Doc: augment Idle feature list and no-subprocess
     section.

   - bpo-25219(20): Update doc for Idle command line options.  Some were
     missing and notes were not correct.

   - bpo-24861(21): Most of idlelib is private and subject to change.
     Use idleib.idle.* to start Idle.  See idlelib.__init__.__doc__.

   - bpo-25199(22): Idle: add synchronization comments for future
     maintainers.

   - bpo-16893(23): Replace help.txt with help.html for Idle doc
     display.  The new idlelib/help.html is rstripped
     Doc/build/html/library/idle.html.  It looks better than help.txt
     and will better document Idle as released.  The tkinter html viewer
     that works for this file was written by Mark Roseman.  The now
     unused EditorWindow.HelpDialog class and helt.txt file are
     deprecated.

   - bpo-24199(24): Deprecate unused idlelib.idlever with possible
     removal in 3.6.

   - bpo-24790(25): Remove extraneous code (which also create 2 & 3
     conflicts).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15348

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24455

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24750

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25313

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24782

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22726

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24820

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25224

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24820

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24972

   (11) https://bugs.python.org/issue?@action=redirect&bpo=24570

   (12) https://bugs.python.org/issue?@action=redirect&bpo=24988

   (13) https://bugs.python.org/issue?@action=redirect&bpo=24801

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25173

   (15) https://bugs.python.org/issue?@action=redirect&bpo=25198

   (16) https://bugs.python.org/issue?@action=redirect&bpo=25225

   (17) https://bugs.python.org/issue?@action=redirect&bpo=21995

   (18) https://bugs.python.org/issue?@action=redirect&bpo=22820

   (19) https://bugs.python.org/issue?@action=redirect&bpo=25224

   (20) https://bugs.python.org/issue?@action=redirect&bpo=25219

   (21) https://bugs.python.org/issue?@action=redirect&bpo=24861

   (22) https://bugs.python.org/issue?@action=redirect&bpo=25199

   (23) https://bugs.python.org/issue?@action=redirect&bpo=16893

   (24) https://bugs.python.org/issue?@action=redirect&bpo=24199

   (25) https://bugs.python.org/issue?@action=redirect&bpo=24790


File: python.info,  Node: Documentation<79>,  Next: Tests<84>,  Prev: IDLE<64>,  Up: Python 3 5 1 release candidate 1

1.23.108.4 Documentation
........................

   - bpo-22558(1): Add remaining doc links to source code for
     Python-coded modules.  Patch by Yoni Lavi.

   - bpo-12067(2): Rewrite Comparisons section in the Expressions
     chapter of the language reference.  Some of the details of
     comparing mixed types were incorrect or ambiguous.  NotImplemented
     is only relevant at a lower level than the Expressions chapter.
     Added details of comparing range() objects, and default behaviour
     and consistency suggestions for user-defined classes.  Patch from
     Andy Maier.

   - bpo-24952(3): Clarify the default size argument of stack_size() in
     the “threading” and “_thread” modules.  Patch from Mattip.

   - bpo-23725(4): Overhaul tempfile docs.  Note deprecated status of
     mktemp.  Patch from Zbigniew Jędrzejewski-Szmek.

   - bpo-24808(5): Update the types of some PyTypeObject fields.  Patch
     by Joseph Weston.

   - bpo-22812(6): Fix unittest discovery examples.  Patch from Pam
     McA’Nulty.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22558

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12067

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24952

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23725

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24808

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22812


File: python.info,  Node: Tests<84>,  Next: Build<91>,  Prev: Documentation<79>,  Up: Python 3 5 1 release candidate 1

1.23.108.5 Tests
................

   - bpo-25449(1): Added tests for OrderedDict subclasses.

   - bpo-25099(2): Make test_compileall not fail when an entry on
     sys.path cannot be written to (commonly seen in administrative
     installs on Windows).

   - bpo-23919(3): Prevents assert dialogs appearing in the test suite.

   - ‘PCbuild\rt.bat’ now accepts an unlimited number of arguments to
     pass along to regrtest.py.  Previously there was a limit of 9.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25449

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25099

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23919


File: python.info,  Node: Build<91>,  Next: Windows<79>,  Prev: Tests<84>,  Up: Python 3 5 1 release candidate 1

1.23.108.6 Build
................

   - bpo-24915(1): Add LLVM support for PGO builds and use the test
     suite to generate the profile data.  Initial patch by Alecsandru
     Patrascu of Intel.

   - bpo-24910(2): Windows MSIs now have unique display names.

   - bpo-24986(3): It is now possible to build Python on Windows without
     errors when external libraries are not available.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24915

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24910

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24986


File: python.info,  Node: Windows<79>,  Next: Tools/Demos<50>,  Prev: Build<91>,  Up: Python 3 5 1 release candidate 1

1.23.108.7 Windows
..................

   - bpo-25450(1): Updates shortcuts to start Python in installation
     directory.

   - bpo-25164(2): Changes default all-users install directory to match
     per-user directory.

   - bpo-25143(3): Improves installer error messages for unsupported
     platforms.

   - bpo-25163(4): Display correct directory in installer when using
     non-default settings.

   - bpo-25361(5): Disables use of SSE2 instructions in Windows 32-bit
     build

   - bpo-25089(6): Adds logging to installer for case where launcher is
     not selected on upgrade.

   - bpo-25165(7): Windows uninstallation should not remove launcher if
     other versions remain

   - bpo-25112(8): py.exe launcher is missing icons

   - bpo-25102(9): Windows installer does not precompile for -O or -OO.

   - bpo-25081(10): Makes Back button in installer go back to upgrade
     page when upgrading.

   - bpo-25091(11): Increases font size of the installer.

   - bpo-25126(12): Clarifies that the non-web installer will download
     some components.

   - bpo-25213(13): Restores requestedExecutionLevel to manifest to
     disable UAC virtualization.

   - bpo-25022(14): Removed very outdated PC/example_nt/ directory.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25450

   (2) https://bugs.python.org/issue?@action=redirect&bpo=25164

   (3) https://bugs.python.org/issue?@action=redirect&bpo=25143

   (4) https://bugs.python.org/issue?@action=redirect&bpo=25163

   (5) https://bugs.python.org/issue?@action=redirect&bpo=25361

   (6) https://bugs.python.org/issue?@action=redirect&bpo=25089

   (7) https://bugs.python.org/issue?@action=redirect&bpo=25165

   (8) https://bugs.python.org/issue?@action=redirect&bpo=25112

   (9) https://bugs.python.org/issue?@action=redirect&bpo=25102

   (10) https://bugs.python.org/issue?@action=redirect&bpo=25081

   (11) https://bugs.python.org/issue?@action=redirect&bpo=25091

   (12) https://bugs.python.org/issue?@action=redirect&bpo=25126

   (13) https://bugs.python.org/issue?@action=redirect&bpo=25213

   (14) https://bugs.python.org/issue?@action=redirect&bpo=25022


File: python.info,  Node: Tools/Demos<50>,  Prev: Windows<79>,  Up: Python 3 5 1 release candidate 1

1.23.108.8 Tools/Demos
......................

   - bpo-25440(1): Fix output of python-config –extension-suffix.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25440


File: python.info,  Node: Python 3 5 0 final,  Next: Python 3 5 0 release candidate 4,  Prev: Python 3 5 1 release candidate 1,  Up: Changelog

1.23.109 Python 3.5.0 final
---------------------------

'Release date: 2015-09-13'

* Menu:

* Build: Build<92>.


File: python.info,  Node: Build<92>,  Up: Python 3 5 0 final

1.23.109.1 Build
................

   - bpo-25071(1): Windows installer should not require TargetDir
     parameter when installing quietly.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25071


File: python.info,  Node: Python 3 5 0 release candidate 4,  Next: Python 3 5 0 release candidate 3,  Prev: Python 3 5 0 final,  Up: Changelog

1.23.110 Python 3.5.0 release candidate 4
-----------------------------------------

'Release date: 2015-09-09'

* Menu:

* Library: Library<172>.
* Build: Build<93>.


File: python.info,  Node: Library<172>,  Next: Build<93>,  Up: Python 3 5 0 release candidate 4

1.23.110.1 Library
..................

   - bpo-25029(1): Fixes MemoryError in test_strptime.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25029


File: python.info,  Node: Build<93>,  Prev: Library<172>,  Up: Python 3 5 0 release candidate 4

1.23.110.2 Build
................

   - bpo-25027(1): Reverts partial-static build options and adds
     vcruntime140.dll to Windows installation.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=25027


File: python.info,  Node: Python 3 5 0 release candidate 3,  Next: Python 3 5 0 release candidate 2,  Prev: Python 3 5 0 release candidate 4,  Up: Changelog

1.23.111 Python 3.5.0 release candidate 3
-----------------------------------------

'Release date: 2015-09-07'

* Menu:

* Core and Builtins: Core and Builtins<171>.
* Library: Library<173>.


File: python.info,  Node: Core and Builtins<171>,  Next: Library<173>,  Up: Python 3 5 0 release candidate 3

1.23.111.1 Core and Builtins
............................

   - bpo-24305(1): Prevent import subsystem stack frames from being
     counted by the warnings.warn(stacklevel=) parameter.

   - bpo-24912(2): Prevent __class__ assignment to immutable built-in
     objects.

   - bpo-24975(3): Fix AST compilation for PEP 448(4) syntax.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24305

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24912

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24975

   (4) https://peps.python.org/pep-0448/


File: python.info,  Node: Library<173>,  Prev: Core and Builtins<171>,  Up: Python 3 5 0 release candidate 3

1.23.111.2 Library
..................

   - bpo-24917(1): time_strftime() buffer over-read.

   - bpo-24748(2): To resolve a compatibility problem found with py2exe
     and pywin32, imp.load_dynamic() once again ignores previously
     loaded modules to support Python modules replacing themselves with
     extension modules.  Patch by Petr Viktorin.

   - bpo-24635(3): Fixed a bug in typing.py where isinstance([],
     typing.Iterable) would return True once, then False on subsequent
     calls.

   - bpo-24989(4): Fixed buffer overread in BytesIO.readline() if a
     position is set beyond size.  Based on patch by John Leitch.

   - bpo-24913(5): Fix overrun error in deque.index().  Found by John
     Leitch and Bryce Darling.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24917

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24748

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24635

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24989

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24913


File: python.info,  Node: Python 3 5 0 release candidate 2,  Next: Python 3 5 0 release candidate 1,  Prev: Python 3 5 0 release candidate 3,  Up: Changelog

1.23.112 Python 3.5.0 release candidate 2
-----------------------------------------

'Release date: 2015-08-25'

* Menu:

* Core and Builtins: Core and Builtins<172>.
* Library: Library<174>.


File: python.info,  Node: Core and Builtins<172>,  Next: Library<174>,  Up: Python 3 5 0 release candidate 2

1.23.112.1 Core and Builtins
............................

   - bpo-24769(1): Interpreter now starts properly when dynamic loading
     is disabled.  Patch by Petr Viktorin.

   - bpo-21167(2): NAN operations are now handled correctly when python
     is compiled with ICC even if -fp-model strict is not specified.

   - bpo-24492(3): A “package” lacking a __name__ attribute when trying
     to perform a ‘from .. import ...’ statement will trigger an
     ImportError instead of an AttributeError.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24769

   (2) https://bugs.python.org/issue?@action=redirect&bpo=21167

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24492


File: python.info,  Node: Library<174>,  Prev: Core and Builtins<172>,  Up: Python 3 5 0 release candidate 2

1.23.112.2 Library
..................

   - bpo-24847(1): Removes vcruntime140.dll dependency from Tcl/Tk.

   - bpo-24839(2): platform._syscmd_ver raises DeprecationWarning

   - bpo-24867(3): Fix Task.get_stack() for ‘async def’ coroutines

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24847

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24839

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24867


File: python.info,  Node: Python 3 5 0 release candidate 1,  Next: Python 3 5 0 beta 4,  Prev: Python 3 5 0 release candidate 2,  Up: Changelog

1.23.113 Python 3.5.0 release candidate 1
-----------------------------------------

'Release date: 2015-08-09'

* Menu:

* Core and Builtins: Core and Builtins<173>.
* Library: Library<175>.
* IDLE: IDLE<65>.
* Documentation: Documentation<80>.
* Tests: Tests<85>.


File: python.info,  Node: Core and Builtins<173>,  Next: Library<175>,  Up: Python 3 5 0 release candidate 1

1.23.113.1 Core and Builtins
............................

   - bpo-24667(1): Resize odict in all cases that the underlying dict
     resizes.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24667


File: python.info,  Node: Library<175>,  Next: IDLE<65>,  Prev: Core and Builtins<173>,  Up: Python 3 5 0 release candidate 1

1.23.113.2 Library
..................

   - bpo-24824(1): Signatures of codecs.encode() and codecs.decode() now
     are compatible with pydoc.

   - bpo-24634(2): Importing uuid should not try to load libc on Windows

   - bpo-24798(3): _msvccompiler.py doesn’t properly support manifests

   - bpo-4395(4): Better testing and documentation of binary operators.
     Patch by Martin Panter.

   - bpo-23973(5): Update typing.py from GitHub repo.

   - bpo-23004(6): mock_open() now reads binary data correctly when the
     type of read_data is bytes.  Initial patch by Aaron Hill.

   - bpo-23888(7): Handle fractional time in cookie expiry.  Patch by
     ssh.

   - bpo-23652(8): Make it possible to compile the select module against
     the libc headers from the Linux Standard Base, which do not include
     some EPOLL macros.  Patch by Matt Frank.

   - bpo-22932(9): Fix timezones in email.utils.formatdate.  Patch from
     Dmitry Shachnev.

   - bpo-23779(10): imaplib raises TypeError if authenticator tries to
     abort.  Patch from Craig Holmquist.

   - bpo-23319(11): Fix ctypes.BigEndianStructure, swap correctly bytes.
     Patch written by Matthieu Gautier.

   - bpo-23254(12): Document how to close the TCPServer listening
     socket.  Patch from Martin Panter.

   - bpo-19450(13): Update Windows and OS X installer builds to use
     SQLite 3.8.11.

   - bpo-17527(14): Add PATCH to wsgiref.validator.  Patch from Luca
     Sbardella.

   - bpo-24791(15): Fix grammar regression for call syntax: ‘g(*a or
     b)’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24824

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24634

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24798

   (4) https://bugs.python.org/issue?@action=redirect&bpo=4395

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23973

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23004

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23888

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23652

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22932

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23779

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23319

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23254

   (13) https://bugs.python.org/issue?@action=redirect&bpo=19450

   (14) https://bugs.python.org/issue?@action=redirect&bpo=17527

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24791


File: python.info,  Node: IDLE<65>,  Next: Documentation<80>,  Prev: Library<175>,  Up: Python 3 5 0 release candidate 1

1.23.113.3 IDLE
...............

   - bpo-23672(1): Allow Idle to edit and run files with astral chars in
     name.  Patch by Mohd Sanad Zaki Rizvi.

   - bpo-24745(2): Idle editor default font.  Switch from Courier to
     platform-sensitive TkFixedFont.  This should not affect current
     customized font selections.  If there is a problem, edit
     $HOME/.idlerc/config-main.cfg and remove ‘‘fontXXX’’ entries from
     [Editor Window].  Patch by Mark Roseman.

   - bpo-21192(3): Idle editor.  When a file is run, put its name in the
     restart bar.  Do not print false prompts.  Original patch by Adnan
     Umer.

   - bpo-13884(4): Idle menus.  Remove tearoff lines.  Patch by Roger
     Serwy.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23672

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24745

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21192

   (4) https://bugs.python.org/issue?@action=redirect&bpo=13884


File: python.info,  Node: Documentation<80>,  Next: Tests<85>,  Prev: IDLE<65>,  Up: Python 3 5 0 release candidate 1

1.23.113.4 Documentation
........................

   - bpo-24129(1): Clarify the reference documentation for name
     resolution.  This includes removing the assumption that readers
     will be familiar with the name resolution scheme Python used prior
     to the introduction of lexical scoping for function namespaces.
     Patch by Ivan Levkivskyi.

   - bpo-20769(2): Improve reload() docs.  Patch by Dorian Pula.

   - bpo-23589(3): Remove duplicate sentence from the FAQ. Patch by
     Yongzhi Pan.

   - bpo-24729(4): Correct IO tutorial to match implementation regarding
     encoding parameter to open function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24129

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20769

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23589

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24729


File: python.info,  Node: Tests<85>,  Prev: Documentation<80>,  Up: Python 3 5 0 release candidate 1

1.23.113.5 Tests
................

   - bpo-24751(1): When running regrtest with the ‘-w’ command line
     option, a test run is no longer marked as a failure if all tests
     succeed when re-run.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24751


File: python.info,  Node: Python 3 5 0 beta 4,  Next: Python 3 5 0 beta 3,  Prev: Python 3 5 0 release candidate 1,  Up: Changelog

1.23.114 Python 3.5.0 beta 4
----------------------------

'Release date: 2015-07-26'

* Menu:

* Core and Builtins: Core and Builtins<174>.
* Library: Library<176>.
* Build: Build<94>.


File: python.info,  Node: Core and Builtins<174>,  Next: Library<176>,  Up: Python 3 5 0 beta 4

1.23.114.1 Core and Builtins
............................

   - bpo-23573(1): Restored optimization of bytes.rfind() and
     bytearray.rfind() for single-byte argument on Linux.

   - bpo-24569(2): Make PEP 448(3) dictionary evaluation more
     consistent.

   - bpo-24583(4): Fix crash when set is mutated while being updated.

   - bpo-24407(5): Fix crash when dict is mutated while being updated.

   - bpo-24619(6): New approach for tokenizing async/await.  As a
     consequence, it is now possible to have one-line ‘async def foo():
     await ..’ functions.

   - bpo-24687(7): Plug refleak on SyntaxError in function parameters
     annotations.

   - bpo-15944(8): memoryview: Allow arbitrary formats when casting to
     bytes.  Patch by Martin Panter.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23573

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24569

   (3) https://peps.python.org/pep-0448/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24583

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24407

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24619

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24687

   (8) https://bugs.python.org/issue?@action=redirect&bpo=15944


File: python.info,  Node: Library<176>,  Next: Build<94>,  Prev: Core and Builtins<174>,  Up: Python 3 5 0 beta 4

1.23.114.2 Library
..................

   - bpo-23441(1): rcompleter now prints a tab character instead of
     displaying possible completions for an empty word.  Initial patch
     by Martin Sekera.

   - bpo-24683(2): Fixed crashes in _json functions called with
     arguments of inappropriate type.

   - bpo-21697(3): shutil.copytree() now correctly handles symbolic
     links that point to directories.  Patch by Eduardo Seabra and
     Thomas Kluyver.

   - bpo-14373(4): Fixed segmentation fault when gc.collect() is called
     during constructing lru_cache (C implementation).

   - bpo-24695(5): Fix a regression in traceback.print_exception().  If
     exc_traceback is None we shouldn’t print a traceback header like
     described in the documentation.

   - bpo-24620(6): Random.setstate() now validates the value of state
     last element.

   - bpo-22485(7): Fixed an issue that caused ‘inspect.getsource’ to
     return incorrect results on nested functions.

   - bpo-22153(8): Improve unittest docs.  Patch from Martin Panter and
     evilzero.

   - bpo-24580(9): Symbolic group references to open group in re
     patterns now are explicitly forbidden as well as numeric group
     references.

   - bpo-24206(10): Fixed __eq__ and __ne__ methods of inspect classes.

   - bpo-24631(11): Fixed regression in the timeit module with multiline
     setup.

   - bpo-18622(12): unittest.mock.mock_open().reset_mock would recurse
     infinitely.  Patch from Nicola Palumbo and Laurent De Buyst.

   - bpo-23661(13): unittest.mock side_effects can now be exceptions
     again.  This was a regression vs Python 3.4.  Patch from Ignacio
     Rossi

   - bpo-24608(14): chunk.Chunk.read() now always returns bytes, not
     str.

   - bpo-18684(15): Fixed reading out of the buffer in the re module.

   - bpo-24259(16): tarfile now raises a ReadError if an archive is
     truncated inside a data segment.

   - bpo-15014(17): SMTP.auth() and SMTP.login() now support RFC 4954’s
     optional initial-response argument to the SMTP AUTH command.

   - bpo-24669(18): Fix inspect.getsource() for ‘async def’ functions.
     Patch by Kai Groner.

   - bpo-24688(19): ast.get_docstring() for ‘async def’ functions.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23441

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24683

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21697

   (4) https://bugs.python.org/issue?@action=redirect&bpo=14373

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24695

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24620

   (7) https://bugs.python.org/issue?@action=redirect&bpo=22485

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22153

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24580

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24206

   (11) https://bugs.python.org/issue?@action=redirect&bpo=24631

   (12) https://bugs.python.org/issue?@action=redirect&bpo=18622

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23661

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24608

   (15) https://bugs.python.org/issue?@action=redirect&bpo=18684

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24259

   (17) https://bugs.python.org/issue?@action=redirect&bpo=15014

   (18) https://bugs.python.org/issue?@action=redirect&bpo=24669

   (19) https://bugs.python.org/issue?@action=redirect&bpo=24688


File: python.info,  Node: Build<94>,  Prev: Library<176>,  Up: Python 3 5 0 beta 4

1.23.114.3 Build
................

   - bpo-24603(1): Update Windows builds and OS X 10.5 installer to use
     OpenSSL 1.0.2d.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24603


File: python.info,  Node: Python 3 5 0 beta 3,  Next: Python 3 5 0 beta 2,  Prev: Python 3 5 0 beta 4,  Up: Changelog

1.23.115 Python 3.5.0 beta 3
----------------------------

'Release date: 2015-07-05'

* Menu:

* Core and Builtins: Core and Builtins<175>.
* Library: Library<177>.
* Tests: Tests<86>.
* Documentation: Documentation<81>.
* Build: Build<95>.


File: python.info,  Node: Core and Builtins<175>,  Next: Library<177>,  Up: Python 3 5 0 beta 3

1.23.115.1 Core and Builtins
............................

   - bpo-24467(1): Fixed possible buffer over-read in bytearray.  The
     bytearray object now always allocates place for trailing null byte
     and it’s buffer now is always null-terminated.

   - Upgrade to Unicode 8.0.0.

   - bpo-24345(2): Add Py_tp_finalize slot for the stable ABI.

   - bpo-24400(3): Introduce a distinct type for PEP 492(4) coroutines;
     add types.CoroutineType, inspect.getcoroutinestate,
     inspect.getcoroutinelocals; coroutines no longer use CO_GENERATOR
     flag; sys.set_coroutine_wrapper works only for ‘async def’
     coroutines; inspect.iscoroutine no longer uses
     collections.abc.Coroutine, it’s intended to test for pure ‘async
     def’ coroutines only; add new opcode: GET_YIELD_FROM_ITER; fix
     generators wrapper used in types.coroutine to be instance of
     collections.abc.Generator; collections.abc.Awaitable and
     collections.abc.Coroutine can no longer be used to detect
     generator-based coroutines–use inspect.isawaitable instead.

   - bpo-24450(5): Add gi_yieldfrom to generators and cr_await to
     coroutines.  Contributed by Benno Leslie and Yury Selivanov.

   - bpo-19235(6): Add new RecursionError exception.  Patch by Georg
     Brandl.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24467

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24345

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24400

   (4) https://peps.python.org/pep-0492/

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24450

   (6) https://bugs.python.org/issue?@action=redirect&bpo=19235


File: python.info,  Node: Library<177>,  Next: Tests<86>,  Prev: Core and Builtins<175>,  Up: Python 3 5 0 beta 3

1.23.115.2 Library
..................

   - bpo-21750(1): mock_open.read_data can now be read from each
     instance, as it could in Python 3.3.

   - bpo-24552(2): Fix use after free in an error case of the _pickle
     module.

   - bpo-24514(3): tarfile now tolerates number fields consisting of
     only whitespace.

   - bpo-19176(4): Fixed doctype() related bugs in C implementation of
     ElementTree.  A deprecation warning no longer issued by XMLParser
     subclass with default doctype() method.  Direct call of doctype()
     now issues a warning.  Parser’s doctype() now is not called if
     target’s doctype() is called.  Based on patch by Martin Panter.

   - bpo-20387(5): Restore semantic round-trip correctness in
     tokenize/untokenize for tab-indented blocks.

   - bpo-24456(6): Fixed possible buffer over-read in adpcm2lin() and
     lin2adpcm() functions of the audioop module.

   - bpo-24336(7): The contextmanager decorator now works with functions
     with keyword arguments called “func” and “self”.  Patch by Martin
     Panter.

   - bpo-24522(8): Fix possible integer overflow in json accelerator
     module.

   - bpo-24489(9): ensure a previously set C errno doesn’t disturb
     cmath.polar().

   - bpo-24408(10): Fixed AttributeError in measure() and metrics()
     methods of tkinter.Font.

   - bpo-14373(11): C implementation of functools.lru_cache() now can be
     used with methods.

   - bpo-24347(12): Set KeyError if PyDict_GetItemWithError returns
     NULL.

   - bpo-24348(13): Drop superfluous incref/decref.

   - bpo-24359(14): Check for changed OrderedDict size during iteration.

   - bpo-24368(15): Support keyword arguments in OrderedDict methods.

   - bpo-24362(16): Simplify the C OrderedDict fast nodes resize logic.

   - bpo-24377(17): Fix a ref leak in OrderedDict.__repr__.

   - bpo-24369(18): Defend against key-changes during iteration.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21750

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24552

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24514

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19176

   (5) https://bugs.python.org/issue?@action=redirect&bpo=20387

   (6) https://bugs.python.org/issue?@action=redirect&bpo=24456

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24336

   (8) https://bugs.python.org/issue?@action=redirect&bpo=24522

   (9) https://bugs.python.org/issue?@action=redirect&bpo=24489

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24408

   (11) https://bugs.python.org/issue?@action=redirect&bpo=14373

   (12) https://bugs.python.org/issue?@action=redirect&bpo=24347

   (13) https://bugs.python.org/issue?@action=redirect&bpo=24348

   (14) https://bugs.python.org/issue?@action=redirect&bpo=24359

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24368

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24362

   (17) https://bugs.python.org/issue?@action=redirect&bpo=24377

   (18) https://bugs.python.org/issue?@action=redirect&bpo=24369


File: python.info,  Node: Tests<86>,  Next: Documentation<81>,  Prev: Library<177>,  Up: Python 3 5 0 beta 3

1.23.115.3 Tests
................

   - bpo-24373(1): _testmultiphase and xxlimited now use tp_traverse and
     tp_finalize to avoid reference leaks encountered when combining
     tp_dealloc with PyType_FromSpec (see bpo-16690(2) for details)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24373

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16690


File: python.info,  Node: Documentation<81>,  Next: Build<95>,  Prev: Tests<86>,  Up: Python 3 5 0 beta 3

1.23.115.4 Documentation
........................

   - bpo-24458(1): Update documentation to cover multi-phase
     initialization for extension modules (PEP 489).  Patch by Petr
     Viktorin.

   - bpo-24351(2): Clarify what is meant by “identifier” in the context
     of string.Template instances.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24458

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24351


File: python.info,  Node: Build<95>,  Prev: Documentation<81>,  Up: Python 3 5 0 beta 3

1.23.115.5 Build
................

   - bpo-24432(1): Update Windows builds and OS X 10.5 installer to use
     OpenSSL 1.0.2c.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24432


File: python.info,  Node: Python 3 5 0 beta 2,  Next: Python 3 5 0 beta 1,  Prev: Python 3 5 0 beta 3,  Up: Changelog

1.23.116 Python 3.5.0 beta 2
----------------------------

'Release date: 2015-05-31'

* Menu:

* Core and Builtins: Core and Builtins<176>.
* Library: Library<178>.


File: python.info,  Node: Core and Builtins<176>,  Next: Library<178>,  Up: Python 3 5 0 beta 2

1.23.116.1 Core and Builtins
............................

   - bpo-24284(1): The startswith and endswith methods of the str class
     no longer return True when finding the empty string and the indexes
     are completely out of range.

   - bpo-24115(2): Update uses of PyObject_IsTrue(), PyObject_Not(),
     PyObject_IsInstance(), PyObject_RichCompareBool() and
     _PyDict_Contains() to check for and handle errors correctly.

   - bpo-24328(3): Fix importing one character extension modules.

   - bpo-11205(4): In dictionary displays, evaluate the key before the
     value.

   - bpo-24285(5): Fixed regression that prevented importing extension
     modules from inside packages.  Patch by Petr Viktorin.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24284

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24115

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24328

   (4) https://bugs.python.org/issue?@action=redirect&bpo=11205

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24285


File: python.info,  Node: Library<178>,  Prev: Core and Builtins<176>,  Up: Python 3 5 0 beta 2

1.23.116.2 Library
..................

   - bpo-23247(1): Fix a crash in the StreamWriter.reset() of CJK
     codecs.

   - bpo-24270(2): Add math.isclose() and cmath.isclose() functions as
     per PEP 485(3).  Contributed by Chris Barker and Tal Einat.

   - bpo-5633(4): Fixed timeit when the statement is a string and the
     setup is not.

   - bpo-24326(5): Fixed audioop.ratecv() with non-default weightB
     argument.  Original patch by David Moore.

   - bpo-16991(6): Add a C implementation of OrderedDict.

   - bpo-23934(7): Fix inspect.signature to fail correctly for builtin
     types lacking signature information.  Initial patch by James
     Powell.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23247

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24270

   (3) https://peps.python.org/pep-0485/

   (4) https://bugs.python.org/issue?@action=redirect&bpo=5633

   (5) https://bugs.python.org/issue?@action=redirect&bpo=24326

   (6) https://bugs.python.org/issue?@action=redirect&bpo=16991

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23934


File: python.info,  Node: Python 3 5 0 beta 1,  Next: Python 3 5 0 alpha 4,  Prev: Python 3 5 0 beta 2,  Up: Changelog

1.23.117 Python 3.5.0 beta 1
----------------------------

'Release date: 2015-05-24'

* Menu:

* Core and Builtins: Core and Builtins<177>.
* Library: Library<179>.
* IDLE: IDLE<66>.
* Tests: Tests<87>.
* Documentation: Documentation<82>.
* Tools/Demos: Tools/Demos<51>.


File: python.info,  Node: Core and Builtins<177>,  Next: Library<179>,  Up: Python 3 5 0 beta 1

1.23.117.1 Core and Builtins
............................

   - bpo-24276(1): Fixed optimization of property descriptor getter.

   - bpo-24268(2): PEP 489: Multi-phase extension module initialization.
     Patch by Petr Viktorin.

   - bpo-23955(3): Add pyvenv.cfg option to suppress
     registry/environment lookup for generating sys.path on Windows.

   - bpo-24257(4): Fixed system error in the comparison of faked
     types.SimpleNamespace.

   - bpo-22939(5): Fixed integer overflow in iterator object.  Patch by
     Clement Rouault.

   - bpo-23985(6): Fix a possible buffer overrun when deleting a slice
     from the front of a bytearray and then appending some other bytes
     data.

   - bpo-24102(7): Fixed exception type checking in standard error
     handlers.

   - bpo-15027(8): The UTF-32 encoder is now 3x to 7x faster.

   - bpo-23290(9): Optimize set_merge() for cases where the target is
     empty.  (Contributed by Serhiy Storchaka.)

   - bpo-2292(10): PEP 448: Additional Unpacking Generalizations.

   - bpo-24096(11): Make warnings.warn_explicit more robust against
     mutation of the warnings.filters list.

   - bpo-23996(12): Avoid a crash when a delegated generator raises an
     unnormalized StopIteration exception.  Patch by Stefan Behnel.

   - bpo-23910(13): Optimize property() getter calls.  Patch by Joe
     Jevnik.

   - bpo-23911(14): Move path-based importlib bootstrap code to a
     separate frozen module.

   - bpo-24192(15): Fix namespace package imports.

   - bpo-24022(16): Fix tokenizer crash when processing undecodable
     source code.

   - bpo-9951(17): Added a hex() method to bytes, bytearray, and
     memoryview.

   - bpo-22906(18): PEP 479: Change StopIteration handling inside
     generators.

   - bpo-24017(19): PEP 492: Coroutines with async and await syntax.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24276

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24268

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23955

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24257

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22939

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23985

   (7) https://bugs.python.org/issue?@action=redirect&bpo=24102

   (8) https://bugs.python.org/issue?@action=redirect&bpo=15027

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23290

   (10) https://bugs.python.org/issue?@action=redirect&bpo=2292

   (11) https://bugs.python.org/issue?@action=redirect&bpo=24096

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23996

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23910

   (14) https://bugs.python.org/issue?@action=redirect&bpo=23911

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24192

   (16) https://bugs.python.org/issue?@action=redirect&bpo=24022

   (17) https://bugs.python.org/issue?@action=redirect&bpo=9951

   (18) https://bugs.python.org/issue?@action=redirect&bpo=22906

   (19) https://bugs.python.org/issue?@action=redirect&bpo=24017


File: python.info,  Node: Library<179>,  Next: IDLE<66>,  Prev: Core and Builtins<177>,  Up: Python 3 5 0 beta 1

1.23.117.2 Library
..................

   - bpo-14373(1): Added C implementation of functools.lru_cache().
     Based on patches by Matt Joiner and Alexey Kachayev.

   - bpo-24230(2): The tempfile module now accepts bytes for prefix,
     suffix and dir parameters and returns bytes in such situations
     (matching the os module APIs).

   - bpo-22189(3): collections.UserString now supports __getnewargs__(),
     __rmod__(), casefold(), format_map(), isprintable(), and
     maketrans().  Patch by Joe Jevnik.

   - bpo-24244(4): Prevents termination when an invalid format string is
     encountered on Windows in strftime.

   - bpo-23973(5): PEP 484: Add the typing module.

   - bpo-23086(6): The collections.abc.Sequence() abstract base class
     added 'start' and 'stop' parameters to the index() mixin.  Patch by
     Devin Jeanpierre.

   - bpo-20035(7): Replaced the ‘tkinter._fix’ module used for setting
     up the Tcl/Tk environment on Windows with a private function in the
     ‘_tkinter’ module that makes no permanent changes to the
     environment.

   - bpo-24257(8): Fixed segmentation fault in sqlite3.Row constructor
     with faked cursor type.

   - bpo-15836(9): assertRaises(), assertRaisesRegex(), assertWarns()
     and assertWarnsRegex() assertments now check the type of the first
     argument to prevent possible user error.  Based on patch by Daniel
     Wagner-Hall.

   - bpo-9858(10): Add missing method stubs to _io.RawIOBase.  Patch by
     Laura Rupprecht.

   - bpo-22955(11): attrgetter, itemgetter and methodcaller objects in
     the operator module now support pickling.  Added readable and
     evaluable repr for these objects.  Based on patch by Josh
     Rosenberg.

   - bpo-22107(12): tempfile.gettempdir() and tempfile.mkdtemp() now try
     again when a directory with the chosen name already exists on
     Windows as well as on Unix.  tempfile.mkstemp() now fails early if
     parent directory is not valid (not exists or is a file) on Windows.

   - bpo-23780(13): Improved error message in os.path.join() with single
     argument.

   - bpo-6598(14): Increased time precision and random number range in
     email.utils.make_msgid() to strengthen the uniqueness of the
     message ID.

   - bpo-24091(15): Fixed various crashes in corner cases in C
     implementation of ElementTree.

   - bpo-21931(16): msilib.FCICreate() now raises TypeError in the case
     of a bad argument instead of a ValueError with a bogus FCI error
     number.  Patch by Jeffrey Armstrong.

   - bpo-13866(17): 'quote_via' argument added to
     urllib.parse.urlencode.

   - bpo-20098(18): New mangle_from policy option for email, default
     True for compat32, but False for all other policies.

   - bpo-24211(19): The email library now supports RFC 6532: it can
     generate headers using utf-8 instead of encoded words.

   - bpo-16314(20): Added support for the LZMA compression in distutils.

   - bpo-21804(21): poplib now supports RFC 6856 (UTF8).

   - bpo-18682(22): Optimized pprint functions for builtin scalar types.

   - bpo-22027(23): smtplib now supports RFC 6531 (SMTPUTF8).

   - bpo-23488(24): Random generator objects now consume 2x less memory
     on 64-bit.

   - bpo-1322(25): platform.dist() and platform.linux_distribution()
     functions are now deprecated.  Initial patch by Vajrasky Kok.

   - bpo-22486(26): Added the math.gcd() function.  The fractions.gcd()
     function now is deprecated.  Based on patch by Mark Dickinson.

   - bpo-24064(27): Property() docstrings are now writeable.  (Patch by
     Berker Peksag.)

   - bpo-22681(28): Added support for the koi8_t encoding.

   - bpo-22682(29): Added support for the kz1048 encoding.

   - bpo-23796(30): peek and read1 methods of BufferedReader now raise
     ValueError if they called on a closed object.  Patch by John
     Hergenroeder.

   - bpo-21795(31): smtpd now supports the 8BITMIME extension whenever
     the new 'decode_data' constructor argument is set to False.

   - bpo-24155(32): optimize heapq.heapify() for better cache
     performance when heapifying large lists.

   - bpo-21800(33): imaplib now supports RFC 5161 (enable), RFC 6855
     (utf8/internationalized email) and automatically encodes non-ASCII
     usernames and passwords to UTF8.

   - bpo-20274(34): When calling a _sqlite.Connection, it now complains
     if passed any keyword arguments.  Previously it silently ignored
     them.

   - bpo-20274(35): Remove ignored and erroneous “kwargs” parameters
     from three METH_VARARGS methods on _sqlite.Connection.

   - bpo-24134(36): assertRaises(), assertRaisesRegex(), assertWarns()
     and assertWarnsRegex() checks now emits a deprecation warning when
     callable is None or keyword arguments except msg is passed in the
     context manager mode.

   - bpo-24018(37): Add a collections.abc.Generator abstract base class.
     Contributed by Stefan Behnel.

   - bpo-23880(38): Tkinter’s getint() and getdouble() now support
     Tcl_Obj.  Tkinter’s getdouble() now supports any numbers (in
     particular int).

   - bpo-22619(39): Added negative limit support in the traceback
     module.  Based on patch by Dmitry Kazakov.

   - bpo-24094(40): Fix possible crash in json.encode with poorly
     behaved dict subclasses.

   - bpo-9246(41): On POSIX, os.getcwd() now supports paths longer than
     1025 bytes.  Patch written by William Orr.

   - bpo-17445(42): add difflib.diff_bytes() to support comparison of
     byte strings (fixes a regression from Python 2).

   - bpo-23917(43): Fall back to sequential compilation when
     ProcessPoolExecutor doesn’t exist.  Patch by Claudiu Popa.

   - bpo-23008(44): Fixed resolving attributes with boolean value is
     False in pydoc.

   - Fix asyncio issue 235: LifoQueue and PriorityQueue’s put didn’t
     increment unfinished tasks (this bug was introduced when
     JoinableQueue was merged with Queue).

   - bpo-23908(45): os functions now reject paths with embedded null
     character on Windows instead of silently truncating them.

   - bpo-23728(46): binascii.crc_hqx() could return an integer outside
     of the range 0-0xffff for empty data.

   - bpo-23887(47): urllib.error.HTTPError now has a proper repr()
     representation.  Patch by Berker Peksag.

   - asyncio: New event loop APIs: set_task_factory() and
     get_task_factory().

   - asyncio: async() function is deprecated in favour of
     ensure_future().

   - bpo-24178(48): asyncio.Lock, Condition, Semaphore, and
     BoundedSemaphore support new ‘async with’ syntax.  Contributed by
     Yury Selivanov.

   - bpo-24179(49): Support ‘async for’ for asyncio.StreamReader.
     Contributed by Yury Selivanov.

   - bpo-24184(50): Add AsyncIterator and AsyncIterable ABCs to
     collections.abc.  Contributed by Yury Selivanov.

   - bpo-22547(51): Implement informative __repr__ for
     inspect.BoundArguments.  Contributed by Yury Selivanov.

   - bpo-24190(52): Implement inspect.BoundArgument.apply_defaults()
     method.  Contributed by Yury Selivanov.

   - bpo-20691(53): Add ‘follow_wrapped’ argument to
     inspect.Signature.from_callable() and inspect.signature().
     Contributed by Yury Selivanov.

   - bpo-24248(54): Deprecate inspect.Signature.from_function() and
     inspect.Signature.from_builtin().

   - bpo-23898(55): Fix inspect.classify_class_attrs() to support
     attributes with overloaded __eq__ and __bool__.  Patch by Mike
     Bayer.

   - bpo-24298(56): Fix inspect.signature() to correctly unwrap wrappers
     around bound methods.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14373

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24230

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22189

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24244

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23973

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23086

   (7) https://bugs.python.org/issue?@action=redirect&bpo=20035

   (8) https://bugs.python.org/issue?@action=redirect&bpo=24257

   (9) https://bugs.python.org/issue?@action=redirect&bpo=15836

   (10) https://bugs.python.org/issue?@action=redirect&bpo=9858

   (11) https://bugs.python.org/issue?@action=redirect&bpo=22955

   (12) https://bugs.python.org/issue?@action=redirect&bpo=22107

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23780

   (14) https://bugs.python.org/issue?@action=redirect&bpo=6598

   (15) https://bugs.python.org/issue?@action=redirect&bpo=24091

   (16) https://bugs.python.org/issue?@action=redirect&bpo=21931

   (17) https://bugs.python.org/issue?@action=redirect&bpo=13866

   (18) https://bugs.python.org/issue?@action=redirect&bpo=20098

   (19) https://bugs.python.org/issue?@action=redirect&bpo=24211

   (20) https://bugs.python.org/issue?@action=redirect&bpo=16314

   (21) https://bugs.python.org/issue?@action=redirect&bpo=21804

   (22) https://bugs.python.org/issue?@action=redirect&bpo=18682

   (23) https://bugs.python.org/issue?@action=redirect&bpo=22027

   (24) https://bugs.python.org/issue?@action=redirect&bpo=23488

   (25) https://bugs.python.org/issue?@action=redirect&bpo=1322

   (26) https://bugs.python.org/issue?@action=redirect&bpo=22486

   (27) https://bugs.python.org/issue?@action=redirect&bpo=24064

   (28) https://bugs.python.org/issue?@action=redirect&bpo=22681

   (29) https://bugs.python.org/issue?@action=redirect&bpo=22682

   (30) https://bugs.python.org/issue?@action=redirect&bpo=23796

   (31) https://bugs.python.org/issue?@action=redirect&bpo=21795

   (32) https://bugs.python.org/issue?@action=redirect&bpo=24155

   (33) https://bugs.python.org/issue?@action=redirect&bpo=21800

   (34) https://bugs.python.org/issue?@action=redirect&bpo=20274

   (35) https://bugs.python.org/issue?@action=redirect&bpo=20274

   (36) https://bugs.python.org/issue?@action=redirect&bpo=24134

   (37) https://bugs.python.org/issue?@action=redirect&bpo=24018

   (38) https://bugs.python.org/issue?@action=redirect&bpo=23880

   (39) https://bugs.python.org/issue?@action=redirect&bpo=22619

   (40) https://bugs.python.org/issue?@action=redirect&bpo=24094

   (41) https://bugs.python.org/issue?@action=redirect&bpo=9246

   (42) https://bugs.python.org/issue?@action=redirect&bpo=17445

   (43) https://bugs.python.org/issue?@action=redirect&bpo=23917

   (44) https://bugs.python.org/issue?@action=redirect&bpo=23008

   (45) https://bugs.python.org/issue?@action=redirect&bpo=23908

   (46) https://bugs.python.org/issue?@action=redirect&bpo=23728

   (47) https://bugs.python.org/issue?@action=redirect&bpo=23887

   (48) https://bugs.python.org/issue?@action=redirect&bpo=24178

   (49) https://bugs.python.org/issue?@action=redirect&bpo=24179

   (50) https://bugs.python.org/issue?@action=redirect&bpo=24184

   (51) https://bugs.python.org/issue?@action=redirect&bpo=22547

   (52) https://bugs.python.org/issue?@action=redirect&bpo=24190

   (53) https://bugs.python.org/issue?@action=redirect&bpo=20691

   (54) https://bugs.python.org/issue?@action=redirect&bpo=24248

   (55) https://bugs.python.org/issue?@action=redirect&bpo=23898

   (56) https://bugs.python.org/issue?@action=redirect&bpo=24298


File: python.info,  Node: IDLE<66>,  Next: Tests<87>,  Prev: Library<179>,  Up: Python 3 5 0 beta 1

1.23.117.3 IDLE
...............

   - bpo-23184(1): remove unused names and imports in idlelib.  Initial
     patch by Al Sweigart.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23184


File: python.info,  Node: Tests<87>,  Next: Documentation<82>,  Prev: IDLE<66>,  Up: Python 3 5 0 beta 1

1.23.117.4 Tests
................

   - bpo-21520(1): test_zipfile no longer fails if the word ‘bad’
     appears anywhere in the name of the current directory.

   - bpo-9517(2): Move script_helper into the support package.  Patch by
     Christie Wilson.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=21520

   (2) https://bugs.python.org/issue?@action=redirect&bpo=9517


File: python.info,  Node: Documentation<82>,  Next: Tools/Demos<51>,  Prev: Tests<87>,  Up: Python 3 5 0 beta 1

1.23.117.5 Documentation
........................

   - bpo-22155(1): Add File Handlers subsection with createfilehandler
     to tkinter doc.  Remove obsolete example from FAQ. Patch by Martin
     Panter.

   - bpo-24029(2): Document the name binding behavior for submodule
     imports.

   - bpo-24077(3): Fix typo in man page for -I command option: -s, not
     -S

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22155

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24029

   (3) https://bugs.python.org/issue?@action=redirect&bpo=24077


File: python.info,  Node: Tools/Demos<51>,  Prev: Documentation<82>,  Up: Python 3 5 0 beta 1

1.23.117.6 Tools/Demos
......................

   - bpo-24000(1): Improved Argument Clinic’s mapping of converters to
     legacy “format units”.  Updated the documentation to match.

   - bpo-24001(2): Argument Clinic converters now use accept={type}
     instead of types={‘type’} to specify the types the converter
     accepts.

   - bpo-23330(3): h2py now supports arbitrary filenames in #include.

   - bpo-24031(4): make patchcheck now supports git checkouts, too.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=24000

   (2) https://bugs.python.org/issue?@action=redirect&bpo=24001

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23330

   (4) https://bugs.python.org/issue?@action=redirect&bpo=24031


File: python.info,  Node: Python 3 5 0 alpha 4,  Next: Python 3 5 0 alpha 3,  Prev: Python 3 5 0 beta 1,  Up: Changelog

1.23.118 Python 3.5.0 alpha 4
-----------------------------

'Release date: 2015-04-19'

* Menu:

* Core and Builtins: Core and Builtins<178>.
* Library: Library<180>.
* Build: Build<96>.
* Tests: Tests<88>.
* Tools/Demos: Tools/Demos<52>.
* C API: C API<76>.


File: python.info,  Node: Core and Builtins<178>,  Next: Library<180>,  Up: Python 3 5 0 alpha 4

1.23.118.1 Core and Builtins
............................

   - bpo-22980(1): Under Linux, GNU/KFreeBSD and the Hurd, C extensions
     now include the architecture triplet in the extension name, to make
     it easy to test builds for different ABIs in the same working tree.
     Under OS X, the extension name now includes PEP 3149(2)-style
     information.

   - bpo-22631(3): Added Linux-specific socket constant
     CAN_RAW_FD_FRAMES. Patch courtesy of Joe Jevnik.

   - bpo-23731(4): Implement PEP 488(5): removal of .pyo files.

   - bpo-23726(6): Don’t enable GC for user subclasses of non-GC types
     that don’t add any new fields.  Patch by Eugene Toder.

   - bpo-23309(7): Avoid a deadlock at shutdown if a daemon thread is
     aborted while it is holding a lock to a buffered I/O object, and
     the main thread tries to use the same I/O object (typically stdout
     or stderr).  A fatal error is emitted instead.

   - bpo-22977(8): Fixed formatting Windows error messages on Wine.
     Patch by Martin Panter.

   - bpo-23466(9): %c, %o, %x, and %X in bytes formatting now raise
     TypeError on non-integer input.

   - bpo-24044(10): Fix possible null pointer dereference in list.sort
     in out of memory conditions.

   - bpo-21354(11): PyCFunction_New function is exposed by python DLL
     again.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22980

   (2) https://peps.python.org/pep-3149/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22631

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23731

   (5) https://peps.python.org/pep-0488/

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23726

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23309

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22977

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23466

   (10) https://bugs.python.org/issue?@action=redirect&bpo=24044

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21354


File: python.info,  Node: Library<180>,  Next: Build<96>,  Prev: Core and Builtins<178>,  Up: Python 3 5 0 alpha 4

1.23.118.2 Library
..................

   - bpo-23840(1): tokenize.open() now closes the temporary binary file
     on error to fix a resource warning.

   - bpo-16914(2): new debuglevel 2 in smtplib adds timestamps to debug
     output.

   - bpo-7159(3): urllib.request now supports sending auth credentials
     automatically after the first 401.  This enhancement is a superset
     of the enhancement from bpo-19494(4) and supersedes that change.

   - bpo-23703(5): Fix a regression in urljoin() introduced in
     901e4e52b20a.  Patch by Demian Brecht.

   - bpo-4254(6): Adds _curses.update_lines_cols().  Patch by Arnon
     Yaari

   - bpo-19933(7): Provide default argument for ndigits in round.  Patch
     by Vajrasky Kok.

   - bpo-23193(8): Add a numeric_owner parameter to
     tarfile.TarFile.extract and tarfile.TarFile.extractall.  Patch by
     Michael Vogt and Eric Smith.

   - bpo-23342(9): Add a subprocess.run() function than returns a
     CalledProcess instance for a more consistent API than the existing
     call* functions.

   - bpo-21217(10): inspect.getsourcelines() now tries to compute the
     start and end lines from the code object, fixing an issue when a
     lambda function is used as decorator argument.  Patch by Thomas
     Ballinger and Allison Kaptur.

   - bpo-24521(11): Fix possible integer overflows in the pickle module.

   - bpo-22931(12): Allow ‘[’ and ‘]’ in cookie values.

   - The keywords attribute of functools.partial is now always a
     dictionary.

   - bpo-23811(13): Add missing newline to the PyCompileError error
     message.  Patch by Alex Shkop.

   - bpo-21116(14): Avoid blowing memory when allocating a
     multiprocessing shared array that’s larger than 50% of the
     available RAM. Patch by Médéric Boquien.

   - bpo-22982(15): Improve BOM handling when seeking to multiple
     positions of a writable text file.

   - bpo-23464(16): Removed deprecated asyncio JoinableQueue.

   - bpo-23529(17): Limit the size of decompressed data when reading
     from GzipFile, BZ2File or LZMAFile.  This defeats denial of service
     attacks using compressed bombs (i.e.  compressed payloads which
     decompress to a huge size).  Patch by Martin Panter and Nikolaus
     Rath.

   - bpo-21859(18): Added Python implementation of io.FileIO.

   - bpo-23865(19): close() methods in multiple modules now are
     idempotent and more robust at shutdown.  If they need to release
     multiple resources, all are released even if errors occur.

   - bpo-23400(20): Raise same exception on both Python 2 and 3 if
     sem_open is not available.  Patch by Davin Potts.

   - bpo-10838(21): The subprocess now module includes SubprocessError
     and TimeoutError in its list of exported names for the users wild
     enough to use ‘from subprocess import *’.

   - bpo-23411(22): Added DefragResult, ParseResult, SplitResult,
     DefragResultBytes, ParseResultBytes, and SplitResultBytes to
     urllib.parse.__all__.  Patch by Martin Panter.

   - bpo-23881(23): urllib.request.ftpwrapper constructor now closes the
     socket if the FTP connection failed to fix a ResourceWarning.

   - bpo-23853(24): *note socket.socket.sendall(): dd6. does no more
     reset the socket timeout each time data is sent successfully.  The
     socket timeout is now the maximum total duration to send all data.

   - bpo-22721(25): An order of multiline pprint output of set or dict
     containing orderable and non-orderable elements no longer depends
     on iteration order of set or dict.

   - bpo-15133(26): _tkinter.tkapp.getboolean() now supports Tcl_Obj and
     always returns bool.  tkinter.BooleanVar now validates input values
     (accepted bool, int, str, and Tcl_Obj).  tkinter.BooleanVar.get()
     now always returns bool.

   - bpo-10590(27): xml.sax.parseString() now supports string argument.

   - bpo-23338(28): Fixed formatting ctypes error messages on Cygwin.
     Patch by Makoto Kato.

   - bpo-15582(29): inspect.getdoc() now follows inheritance chains.

   - bpo-2175(30): SAX parsers now support a character stream of
     InputSource object.

   - bpo-16840(31): Tkinter now supports 64-bit integers added in Tcl
     8.4 and arbitrary precision integers added in Tcl 8.5.

   - bpo-23834(32): Fix socket.sendto(), use the C Py_ssize_t type to
     store the result of sendto() instead of the C int type.

   - bpo-23618(33): *note socket.socket.connect(): dd1. now waits until
     the connection completes instead of raising *note InterruptedError:
     db6. if the connection is interrupted by signals, signal handlers
     don’t raise an exception and the socket is blocking or has a
     timeout.  ‘socket.socket.connect()’ still raise ‘InterruptedError’
     for non-blocking sockets.

   - bpo-21526(34): Tkinter now supports new boolean type in Tcl 8.5.

   - bpo-23836(35): Fix the faulthandler module to handle reentrant
     calls to its signal handlers.

   - bpo-23838(36): linecache now clears the cache and returns an empty
     result on MemoryError.

   - bpo-10395(37): Added os.path.commonpath().  Implemented in
     posixpath and ntpath.  Based on patch by Rafik Draoui.

   - bpo-23611(38): Serializing more “lookupable” objects (such as
     unbound methods or nested classes) now are supported with pickle
     protocols < 4.

   - bpo-13583(39): sqlite3.Row now supports slice indexing.

   - bpo-18473(40): Fixed 2to3 and 3to2 compatible pickle mappings.
     Fixed ambiguous reverse mappings.  Added many new mappings.  Import
     mapping is no longer applied to modules already mapped with full
     name mapping.

   - bpo-23485(41): select.select() is now retried automatically with
     the recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception.  This change is part of the PEP
     475(42).

   - bpo-23752(43): When built from an existing file descriptor,
     io.FileIO() now only calls fstat() once.  Before fstat() was called
     twice, which was not necessary.

   - bpo-23704(44): collections.deque() objects now support __add__,
     __mul__, and __imul__().

   - bpo-23171(45): csv.Writer.writerow() now supports arbitrary
     iterables.

   - bpo-23745(46): The new email header parser now handles duplicate
     MIME parameter names without error, similar to how get_param
     behaves.

   - bpo-22117(47): Fix os.utime(), it now rounds the timestamp towards
     minus infinity (-inf) instead of rounding towards zero.

   - bpo-23310(48): Fix MagicMock’s initializer to work with
     __methods__, just like configure_mock().  Patch by Kasia Jachim.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23840

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16914

   (3) https://bugs.python.org/issue?@action=redirect&bpo=7159

   (4) https://bugs.python.org/issue?@action=redirect&bpo=19494

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23703

   (6) https://bugs.python.org/issue?@action=redirect&bpo=4254

   (7) https://bugs.python.org/issue?@action=redirect&bpo=19933

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23193

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23342

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21217

   (11) https://bugs.python.org/issue?@action=redirect&bpo=24521

   (12) https://bugs.python.org/issue?@action=redirect&bpo=22931

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23811

   (14) https://bugs.python.org/issue?@action=redirect&bpo=21116

   (15) https://bugs.python.org/issue?@action=redirect&bpo=22982

   (16) https://bugs.python.org/issue?@action=redirect&bpo=23464

   (17) https://bugs.python.org/issue?@action=redirect&bpo=23529

   (18) https://bugs.python.org/issue?@action=redirect&bpo=21859

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23865

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23400

   (21) https://bugs.python.org/issue?@action=redirect&bpo=10838

   (22) https://bugs.python.org/issue?@action=redirect&bpo=23411

   (23) https://bugs.python.org/issue?@action=redirect&bpo=23881

   (24) https://bugs.python.org/issue?@action=redirect&bpo=23853

   (25) https://bugs.python.org/issue?@action=redirect&bpo=22721

   (26) https://bugs.python.org/issue?@action=redirect&bpo=15133

   (27) https://bugs.python.org/issue?@action=redirect&bpo=10590

   (28) https://bugs.python.org/issue?@action=redirect&bpo=23338

   (29) https://bugs.python.org/issue?@action=redirect&bpo=15582

   (30) https://bugs.python.org/issue?@action=redirect&bpo=2175

   (31) https://bugs.python.org/issue?@action=redirect&bpo=16840

   (32) https://bugs.python.org/issue?@action=redirect&bpo=23834

   (33) https://bugs.python.org/issue?@action=redirect&bpo=23618

   (34) https://bugs.python.org/issue?@action=redirect&bpo=21526

   (35) https://bugs.python.org/issue?@action=redirect&bpo=23836

   (36) https://bugs.python.org/issue?@action=redirect&bpo=23838

   (37) https://bugs.python.org/issue?@action=redirect&bpo=10395

   (38) https://bugs.python.org/issue?@action=redirect&bpo=23611

   (39) https://bugs.python.org/issue?@action=redirect&bpo=13583

   (40) https://bugs.python.org/issue?@action=redirect&bpo=18473

   (41) https://bugs.python.org/issue?@action=redirect&bpo=23485

   (42) https://peps.python.org/pep-0475/

   (43) https://bugs.python.org/issue?@action=redirect&bpo=23752

   (44) https://bugs.python.org/issue?@action=redirect&bpo=23704

   (45) https://bugs.python.org/issue?@action=redirect&bpo=23171

   (46) https://bugs.python.org/issue?@action=redirect&bpo=23745

   (47) https://bugs.python.org/issue?@action=redirect&bpo=22117

   (48) https://bugs.python.org/issue?@action=redirect&bpo=23310


File: python.info,  Node: Build<96>,  Next: Tests<88>,  Prev: Library<180>,  Up: Python 3 5 0 alpha 4

1.23.118.3 Build
................

   - bpo-23817(1): FreeBSD now uses “1.0” in the SOVERSION as other
     operating systems, instead of just “1”.

   - bpo-23501(2): Argument Clinic now generates code into separate
     files by default.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23817

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23501


File: python.info,  Node: Tests<88>,  Next: Tools/Demos<52>,  Prev: Build<96>,  Up: Python 3 5 0 alpha 4

1.23.118.4 Tests
................

   - bpo-23799(1): Added test.support.start_threads() for running and
     cleaning up multiple threads.

   - bpo-22390(2): test.regrtest now emits a warning if temporary files
     or directories are left after running a test.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23799

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22390


File: python.info,  Node: Tools/Demos<52>,  Next: C API<76>,  Prev: Tests<88>,  Up: Python 3 5 0 alpha 4

1.23.118.5 Tools/Demos
......................

   - bpo-18128(1): pygettext now uses standard +NNNN format in the
     POT-Creation-Date header.

   - bpo-23935(2): Argument Clinic’s understanding of format units
     accepting bytes, bytearrays, and buffers is now consistent with
     both the documentation and the implementation.

   - bpo-23944(3): Argument Clinic now wraps long impl prototypes at
     column 78.

   - bpo-20586(4): Argument Clinic now ensures that functions without
     docstrings have signatures.

   - bpo-23492(5): Argument Clinic now generates argument parsing code
     with PyArg_Parse instead of PyArg_ParseTuple if possible.

   - bpo-23500(6): Argument Clinic is now smarter about generating the
     “#ifndef” (empty) definition of the methoddef macro: it’s only
     generated once, even if Argument Clinic processes the same symbol
     multiple times, and it’s emitted at the end of all processing
     rather than immediately after the first use.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18128

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23935

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23944

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20586

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23492

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23500


File: python.info,  Node: C API<76>,  Prev: Tools/Demos<52>,  Up: Python 3 5 0 alpha 4

1.23.118.6 C API
................

   - bpo-23998(1): PyImport_ReInitLock() now checks for lock allocation
     error

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23998


File: python.info,  Node: Python 3 5 0 alpha 3,  Next: Python 3 5 0 alpha 2,  Prev: Python 3 5 0 alpha 4,  Up: Changelog

1.23.119 Python 3.5.0 alpha 3
-----------------------------

'Release date: 2015-03-28'

* Menu:

* Core and Builtins: Core and Builtins<179>.
* Library: Library<181>.
* Build: Build<97>.
* Tests: Tests<89>.
* Tools/Demos: Tools/Demos<53>.


File: python.info,  Node: Core and Builtins<179>,  Next: Library<181>,  Up: Python 3 5 0 alpha 3

1.23.119.1 Core and Builtins
............................

   - bpo-23573(1): Increased performance of string search operations
     (str.find, str.index, str.count, the in operator, str.split,
     str.partition) with arguments of different kinds (UCS1, UCS2,
     UCS4).

   - bpo-23753(2): Python doesn’t support anymore platforms without
     stat() or fstat(), these functions are always required.

   - bpo-23681(3): The -b option now affects comparisons of bytes with
     int.

   - bpo-23632(4): Memoryviews now allow tuple indexing (including for
     multi-dimensional memoryviews).

   - bpo-23192(5): Fixed generator lambdas.  Patch by Bruno Cauet.

   - bpo-23629(6): Fix the default __sizeof__ implementation for
     variable-sized objects.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23573

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23753

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23681

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23632

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23192

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23629


File: python.info,  Node: Library<181>,  Next: Build<97>,  Prev: Core and Builtins<179>,  Up: Python 3 5 0 alpha 3

1.23.119.2 Library
..................

   - bpo-14260(1): The groupindex attribute of regular expression
     pattern object now is non-modifiable mapping.

   - bpo-23792(2): Ignore KeyboardInterrupt when the pydoc pager is
     active.  This mimics the behavior of the standard unix pagers, and
     prevents pipepager from shutting down while the pager itself is
     still running.

   - bpo-23775(3): pprint() of OrderedDict now outputs the same
     representation as repr().

   - bpo-23765(4): Removed IsBadStringPtr calls in ctypes

   - bpo-22364(5): Improved some re error messages using regex for
     hints.

   - bpo-23742(6): ntpath.expandvars() no longer loses unbalanced single
     quotes.

   - bpo-21717(7): The zipfile.ZipFile.open function now supports ‘x’
     (exclusive creation) mode.

   - bpo-21802(8): The reader in BufferedRWPair now is closed even when
     closing writer failed in BufferedRWPair.close().

   - bpo-23622(9): Unknown escapes in regular expressions that consist
     of ‘'\'’ and ASCII letter now raise a deprecation warning and will
     be forbidden in Python 3.6.

   - bpo-23671(10): string.Template now allows specifying the “self”
     parameter as a keyword argument.  string.Formatter now allows
     specifying the “self” and the “format_string” parameters as keyword
     arguments.

   - bpo-23502(11): The pprint module now supports mapping proxies.

   - bpo-17530(12): pprint now wraps long bytes objects and bytearrays.

   - bpo-22687(13): Fixed some corner cases in breaking words in
     tetxtwrap.  Got rid of quadratic complexity in breaking long words.

   - bpo-4727(14): The copy module now uses pickle protocol 4 (PEP 3154)
     and supports copying of instances of classes whose __new__ method
     takes keyword-only arguments.

   - bpo-23491(15): Added a zipapp module to support creating executable
     zip file archives of Python code.  Registered “.pyz” and “.pyzw”
     extensions on Windows for these archives (PEP 441).

   - bpo-23657(16): Avoid explicit checks for str in zipapp, adding
     support for pathlib.Path objects as arguments.

   - bpo-23688(17): Added support of arbitrary bytes-like objects and
     avoided unnecessary copying of memoryview in gzip.GzipFile.write().
     Original patch by Wolfgang Maier.

   - bpo-23252(18): Added support for writing ZIP files to unseekable
     streams.

   - bpo-23647(19): Increase imaplib’s MAXLINE to accommodate modern
     mailbox sizes.

   - bpo-23539(20): If body is None, http.client.HTTPConnection.request
     now sets Content-Length to 0 for PUT, POST, and PATCH headers to
     avoid 411 errors from some web servers.

   - bpo-22351(21): The nntplib.NNTP constructor no longer leaves the
     connection and socket open until the garbage collector cleans them
     up.  Patch by Martin Panter.

   - bpo-23704(22): collections.deque() objects now support methods for
     index(), insert(), and copy().  This allows deques to be registered
     as a MutableSequence and it improves their substitutability for
     lists.

   - bpo-23715(23): *note signal.sigwaitinfo(): dd9. and *note
     signal.sigtimedwait(): dd8. are now retried when interrupted by a
     signal not in the 'sigset' parameter, if the signal handler does
     not raise an exception.  signal.sigtimedwait() recomputes the
     timeout with a monotonic clock when it is retried.

   - bpo-23001(24): Few functions in modules mmap, ossaudiodev, socket,
     ssl, and codecs, that accepted only read-only bytes-like object now
     accept writable bytes-like object too.

   - bpo-23646(25): If time.sleep() is interrupted by a signal, the
     sleep is now retried with the recomputed delay, except if the
     signal handler raises an exception (PEP 475).

   - bpo-23136(26): _strptime now uniformly handles all days in week 0,
     including Dec 30 of previous year.  Based on patch by Jim Carroll.

   - bpo-23700(27): Iterator of NamedTemporaryFile now keeps a reference
     to NamedTemporaryFile instance.  Patch by Bohuslav Kabrda.

   - bpo-22903(28): The fake test case created by unittest.loader when
     it fails importing a test module is now picklable.

   - bpo-22181(29): On Linux, os.urandom() now uses the new getrandom()
     syscall if available, syscall introduced in the Linux kernel 3.17.
     It is more reliable and more secure, because it avoids the need of
     a file descriptor and waits until the kernel has enough entropy.

   - bpo-2211(30): Updated the implementation of the http.cookies.Morsel
     class.  Setting attributes key, value and coded_value directly now
     is deprecated.  update() and setdefault() now transform and check
     keys.  Comparing for equality now takes into account attributes
     key, value and coded_value.  copy() now returns a Morsel, not a
     dict.  repr() now contains all attributes.  Optimized checking keys
     and quoting values.  Added new tests.  Original patch by Demian
     Brecht.

   - bpo-18983(31): Allow selection of output units in timeit.  Patch by
     Julian Gindi.

   - bpo-23631(32): Fix traceback.format_list when a traceback has been
     mutated.

   - bpo-23568(33): Add rdivmod support to MagicMock() objects.  Patch
     by Håkan Lövdahl.

   - bpo-2052(34): Add charset parameter to HtmlDiff.make_file().

   - bpo-23668(35): Support os.truncate and os.ftruncate on Windows.

   - bpo-23138(36): Fixed parsing cookies with absent keys or values in
     cookiejar.  Patch by Demian Brecht.

   - bpo-23051(37): multiprocessing.Pool methods imap() and
     imap_unordered() now handle exceptions raised by an iterator.
     Patch by Alon Diamant and Davin Potts.

   - bpo-23581(38): Add matmul support to MagicMock.  Patch by Håkan
     Lövdahl.

   - bpo-23566(39): enable(), register(), dump_traceback() and
     dump_traceback_later() functions of faulthandler now accept file
     descriptors.  Patch by Wei Wu.

   - bpo-22928(40): Disabled HTTP header injections in http.client.
     Original patch by Demian Brecht.

   - bpo-23615(41): Modules bz2, tarfile and tokenize now can be
     reloaded with imp.reload().  Patch by Thomas Kluyver.

   - bpo-23605(42): os.walk() now calls os.scandir() instead of
     os.listdir().  The usage of os.scandir() reduces the number of
     calls to os.stat().  Initial patch written by Ben Hoyt.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14260

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23792

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23775

   (4) https://bugs.python.org/issue?@action=redirect&bpo=23765

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22364

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23742

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21717

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21802

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23622

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23671

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23502

   (12) https://bugs.python.org/issue?@action=redirect&bpo=17530

   (13) https://bugs.python.org/issue?@action=redirect&bpo=22687

   (14) https://bugs.python.org/issue?@action=redirect&bpo=4727

   (15) https://bugs.python.org/issue?@action=redirect&bpo=23491

   (16) https://bugs.python.org/issue?@action=redirect&bpo=23657

   (17) https://bugs.python.org/issue?@action=redirect&bpo=23688

   (18) https://bugs.python.org/issue?@action=redirect&bpo=23252

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23647

   (20) https://bugs.python.org/issue?@action=redirect&bpo=23539

   (21) https://bugs.python.org/issue?@action=redirect&bpo=22351

   (22) https://bugs.python.org/issue?@action=redirect&bpo=23704

   (23) https://bugs.python.org/issue?@action=redirect&bpo=23715

   (24) https://bugs.python.org/issue?@action=redirect&bpo=23001

   (25) https://bugs.python.org/issue?@action=redirect&bpo=23646

   (26) https://bugs.python.org/issue?@action=redirect&bpo=23136

   (27) https://bugs.python.org/issue?@action=redirect&bpo=23700

   (28) https://bugs.python.org/issue?@action=redirect&bpo=22903

   (29) https://bugs.python.org/issue?@action=redirect&bpo=22181

   (30) https://bugs.python.org/issue?@action=redirect&bpo=2211

   (31) https://bugs.python.org/issue?@action=redirect&bpo=18983

   (32) https://bugs.python.org/issue?@action=redirect&bpo=23631

   (33) https://bugs.python.org/issue?@action=redirect&bpo=23568

   (34) https://bugs.python.org/issue?@action=redirect&bpo=2052

   (35) https://bugs.python.org/issue?@action=redirect&bpo=23668

   (36) https://bugs.python.org/issue?@action=redirect&bpo=23138

   (37) https://bugs.python.org/issue?@action=redirect&bpo=23051

   (38) https://bugs.python.org/issue?@action=redirect&bpo=23581

   (39) https://bugs.python.org/issue?@action=redirect&bpo=23566

   (40) https://bugs.python.org/issue?@action=redirect&bpo=22928

   (41) https://bugs.python.org/issue?@action=redirect&bpo=23615

   (42) https://bugs.python.org/issue?@action=redirect&bpo=23605


File: python.info,  Node: Build<97>,  Next: Tests<89>,  Prev: Library<181>,  Up: Python 3 5 0 alpha 3

1.23.119.3 Build
................

   - bpo-23585(1): make patchcheck will ensure the interpreter is built.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23585


File: python.info,  Node: Tests<89>,  Next: Tools/Demos<53>,  Prev: Build<97>,  Up: Python 3 5 0 alpha 3

1.23.119.4 Tests
................

   - bpo-23583(1): Added tests for standard IO streams in IDLE.

   - bpo-22289(2): Prevent test_urllib2net failures due to ftp
     connection timeout.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23583

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22289


File: python.info,  Node: Tools/Demos<53>,  Prev: Tests<89>,  Up: Python 3 5 0 alpha 3

1.23.119.5 Tools/Demos
......................

   - bpo-22826(1): The result of open() in Tools/freeze/bkfile.py is now
     better compatible with regular files (in particular it now supports
     the context management protocol).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22826


File: python.info,  Node: Python 3 5 0 alpha 2,  Next: Python 3 5 0 alpha 1,  Prev: Python 3 5 0 alpha 3,  Up: Changelog

1.23.120 Python 3.5.0 alpha 2
-----------------------------

'Release date: 2015-03-09'

* Menu:

* Core and Builtins: Core and Builtins<180>.
* Library: Library<182>.
* Build: Build<98>.
* C API: C API<77>.
* Windows: Windows<80>.


File: python.info,  Node: Core and Builtins<180>,  Next: Library<182>,  Up: Python 3 5 0 alpha 2

1.23.120.1 Core and Builtins
............................

   - bpo-23571(1): PyObject_Call() and PyCFunction_Call() now raise a
     SystemError if a function returns a result and raises an exception.
     The SystemError is chained to the previous exception.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23571


File: python.info,  Node: Library<182>,  Next: Build<98>,  Prev: Core and Builtins<180>,  Up: Python 3 5 0 alpha 2

1.23.120.2 Library
..................

   - bpo-22524(1): New os.scandir() function, part of the PEP 471(2):
     “os.scandir() function – a better and faster directory iterator”.
     Patch written by Ben Hoyt.

   - bpo-23103(3): Reduced the memory consumption of IPv4Address and
     IPv6Address.

   - bpo-21793(4): BaseHTTPRequestHandler again logs response code as
     numeric, not as stringified enum.  Patch by Demian Brecht.

   - bpo-23476(5): In the ssl module, enable OpenSSL’s
     X509_V_FLAG_TRUSTED_FIRST flag on certificate stores when it is
     available.

   - bpo-23576(6): Avoid stalling in SSL reads when EOF has been reached
     in the SSL layer but the underlying connection hasn’t been closed.

   - bpo-23504(7): Added an __all__ to the types module.

   - bpo-23563(8): Optimized utility functions in urllib.parse.

   - bpo-7830(9): Flatten nested functools.partial.

   - bpo-20204(10): Added the __module__ attribute to _tkinter classes.

   - bpo-19980(11): Improved help() for non-recognized strings.
     help(‘’) now shows the help on str.  help(‘help’) now shows the
     help on help().  Original patch by Mark Lawrence.

   - bpo-23521(12): Corrected pure python implementation of timedelta
     division.  Eliminated OverflowError from ‘timedelta * float’ for
     some floats; Corrected rounding in timedelta true division.

   - bpo-21619(13): Popen objects no longer leave a zombie after exit in
     the with statement if the pipe was broken.  Patch by Martin Panter.

   - bpo-22936(14): Make it possible to show local variables in
     tracebacks for both the traceback module and unittest.

   - bpo-15955(15): Add an option to limit the output size in
     bz2.decompress().  Patch by Nikolaus Rath.

   - bpo-6639(16): Module-level turtle functions no longer raise
     TclError after closing the window.

   - bpo-814253(17): Group references and conditional group references
     now work in lookbehind assertions in regular expressions.  (See
     also: bpo-9179(18))

   - bpo-23215(19): Multibyte codecs with custom error handlers that
     ignores errors consumed too much memory and raised SystemError or
     MemoryError.  Original patch by Aleksi Torhamo.

   - bpo-5700(20): io.FileIO() called flush() after closing the file.
     flush() was not called in close() if closefd=False.

   - bpo-23374(21): Fixed pydoc failure with non-ASCII files when stdout
     encoding differs from file system encoding (e.g.  on Mac OS).

   - bpo-23481(22): Remove RC4 from the SSL module’s default cipher
     list.

   - bpo-21548(23): Fix pydoc.synopsis() and pydoc.apropos() on modules
     with empty docstrings.

   - bpo-22885(24): Fixed arbitrary code execution vulnerability in the
     dbm.dumb module.  Original patch by Claudiu Popa.

   - bpo-23239(25): ssl.match_hostname() now supports matching of IP
     addresses.

   - bpo-23146(26): Fix mishandling of absolute Windows paths with
     forward slashes in pathlib.

   - bpo-23096(27): Pickle representation of floats with protocol 0 now
     is the same for both Python and C implementations.

   - bpo-19105(28): pprint now more efficiently uses free space at the
     right.

   - bpo-14910(29): Add allow_abbrev parameter to
     argparse.ArgumentParser.  Patch by Jonathan Paugh, Steven Bethard,
     paul j3 and Daniel Eriksson.

   - bpo-21717(30): tarfile.open() now supports ‘x’ (exclusive creation)
     mode.

   - bpo-23344(31): marshal.dumps() is now 20-25% faster on average.

   - bpo-20416(32): marshal.dumps() with protocols 3 and 4 is now 40-50%
     faster on average.

   - bpo-23421(33): Fixed compression in tarfile CLI. Patch by wdv4758h.

   - bpo-23367(34): Fix possible overflows in the unicodedata module.

   - bpo-23361(35): Fix possible overflow in Windows subprocess creation
     code.

   - logging.handlers.QueueListener now takes a respect_handler_level
     keyword argument which, if set to True, will pass messages to
     handlers taking handler levels into account.

   - bpo-19705(36): turtledemo now has a visual sorting algorithm demo.
     Original patch from Jason Yeo.

   - bpo-23801(37): Fix issue where cgi.FieldStorage did not always
     ignore the entire preamble to a multipart body.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22524

   (2) https://peps.python.org/pep-0471/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23103

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21793

   (5) https://bugs.python.org/issue?@action=redirect&bpo=23476

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23576

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23504

   (8) https://bugs.python.org/issue?@action=redirect&bpo=23563

   (9) https://bugs.python.org/issue?@action=redirect&bpo=7830

   (10) https://bugs.python.org/issue?@action=redirect&bpo=20204

   (11) https://bugs.python.org/issue?@action=redirect&bpo=19980

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23521

   (13) https://bugs.python.org/issue?@action=redirect&bpo=21619

   (14) https://bugs.python.org/issue?@action=redirect&bpo=22936

   (15) https://bugs.python.org/issue?@action=redirect&bpo=15955

   (16) https://bugs.python.org/issue?@action=redirect&bpo=6639

   (17) https://bugs.python.org/issue?@action=redirect&bpo=814253

   (18) https://bugs.python.org/issue?@action=redirect&bpo=9179

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23215

   (20) https://bugs.python.org/issue?@action=redirect&bpo=5700

   (21) https://bugs.python.org/issue?@action=redirect&bpo=23374

   (22) https://bugs.python.org/issue?@action=redirect&bpo=23481

   (23) https://bugs.python.org/issue?@action=redirect&bpo=21548

   (24) https://bugs.python.org/issue?@action=redirect&bpo=22885

   (25) https://bugs.python.org/issue?@action=redirect&bpo=23239

   (26) https://bugs.python.org/issue?@action=redirect&bpo=23146

   (27) https://bugs.python.org/issue?@action=redirect&bpo=23096

   (28) https://bugs.python.org/issue?@action=redirect&bpo=19105

   (29) https://bugs.python.org/issue?@action=redirect&bpo=14910

   (30) https://bugs.python.org/issue?@action=redirect&bpo=21717

   (31) https://bugs.python.org/issue?@action=redirect&bpo=23344

   (32) https://bugs.python.org/issue?@action=redirect&bpo=20416

   (33) https://bugs.python.org/issue?@action=redirect&bpo=23421

   (34) https://bugs.python.org/issue?@action=redirect&bpo=23367

   (35) https://bugs.python.org/issue?@action=redirect&bpo=23361

   (36) https://bugs.python.org/issue?@action=redirect&bpo=19705

   (37) https://bugs.python.org/issue?@action=redirect&bpo=23801


File: python.info,  Node: Build<98>,  Next: C API<77>,  Prev: Library<182>,  Up: Python 3 5 0 alpha 2

1.23.120.3 Build
................

   - bpo-23445(1): pydebug builds now use “gcc -Og” where possible, to
     make the resulting executable faster.

   - bpo-23686(2): Update OS X 10.5 installer build to use OpenSSL
     1.0.2a.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23445

   (2) https://bugs.python.org/issue?@action=redirect&bpo=23686


File: python.info,  Node: C API<77>,  Next: Windows<80>,  Prev: Build<98>,  Up: Python 3 5 0 alpha 2

1.23.120.4 C API
................

   - bpo-20204(1): Deprecation warning is now raised for builtin types
     without the __module__ attribute.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20204


File: python.info,  Node: Windows<80>,  Prev: C API<77>,  Up: Python 3 5 0 alpha 2

1.23.120.5 Windows
..................

   - bpo-23465(1): Implement PEP 486(2) - Make the Python Launcher aware
     of virtual environments.  Patch by Paul Moore.

   - bpo-23437(3): Make user scripts directory versioned on Windows.
     Patch by Paul Moore.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23465

   (2) https://peps.python.org/pep-0486/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=23437


File: python.info,  Node: Python 3 5 0 alpha 1,  Prev: Python 3 5 0 alpha 2,  Up: Changelog

1.23.121 Python 3.5.0 alpha 1
-----------------------------

'Release date: 2015-02-08'

* Menu:

* Core and Builtins: Core and Builtins<181>.
* Library: Library<183>.
* IDLE: IDLE<67>.
* Build: Build<99>.
* C API: C API<78>.
* Documentation: Documentation<83>.
* Tests: Tests<90>.
* Tools/Demos: Tools/Demos<54>.
* Windows: Windows<81>.


File: python.info,  Node: Core and Builtins<181>,  Next: Library<183>,  Up: Python 3 5 0 alpha 1

1.23.121.1 Core and Builtins
............................

   - bpo-23285(1): PEP 475 - EINTR handling.

   - bpo-22735(2): Fix many edge cases (including crashes) involving
     custom mro() implementations.

   - bpo-22896(3): Avoid using PyObject_AsCharBuffer(),
     PyObject_AsReadBuffer() and PyObject_AsWriteBuffer().

   - bpo-21295(4): Revert some changes (bpo-16795(5)) to AST line
     numbers and column offsets that constituted a regression.

   - bpo-22986(6): Allow changing an object’s __class__ between a
     dynamic type and static type in some cases.

   - bpo-15859(7): PyUnicode_EncodeFSDefault(), PyUnicode_EncodeMBCS()
     and PyUnicode_EncodeCodePage() now raise an exception if the object
     is not a Unicode object.  For PyUnicode_EncodeFSDefault(), it was
     already the case on platforms other than Windows.  Patch written by
     Campbell Barton.

   - bpo-21408(8): The default __ne__() now returns NotImplemented if
     __eq__() returned NotImplemented.  Original patch by Martin Panter.

   - bpo-23321(9): Fixed a crash in str.decode() when error handler
     returned replacement string longer than malformed input data.

   - bpo-22286(10): The “backslashreplace” error handlers now works with
     decoding and translating.

   - bpo-23253(11): Delay-load ShellExecute[AW] in os.startfile for
     reduced startup overhead on Windows.

   - bpo-22038(12): pyatomic.h now uses stdatomic.h or GCC built-in
     functions for atomic memory access if available.  Patch written by
     Vitor de Lima and Gustavo Temple.

   - bpo-20284(13): %-interpolation (aka printf) formatting added for
     bytes and bytearray.

   - bpo-23048(14): Fix jumping out of an infinite while loop in the
     pdb.

   - bpo-20335(15): bytes constructor now raises TypeError when encoding
     or errors is specified with non-string argument.  Based on patch by
     Renaud Blanch.

   - bpo-22834(16): If the current working directory ends up being set
     to a non-existent directory then import will no longer raise
     FileNotFoundError.

   - bpo-22869(17): Move the interpreter startup & shutdown code to a
     new dedicated pylifecycle.c module

   - bpo-22847(18): Improve method cache efficiency.

   - bpo-22335(19): Fix crash when trying to enlarge a bytearray to
     0x7fffffff bytes on a 32-bit platform.

   - bpo-22653(20): Fix an assertion failure in debug mode when doing a
     reentrant dict insertion in debug mode.

   - bpo-22643(21): Fix integer overflow in Unicode case operations
     (upper, lower, title, swapcase, casefold).

   - bpo-17636(22): Circular imports involving relative imports are now
     supported.

   - bpo-22604(23): Fix assertion error in debug mode when dividing a
     complex number by (nan+0j).

   - bpo-21052(24): Do not raise ImportWarning when sys.path_hooks or
     sys.meta_path are set to None.

   - bpo-16518(25): Use ‘bytes-like object required’ in error messages
     that previously used the far more cryptic “‘x’ does not support the
     buffer protocol.

   - bpo-22470(26): Fixed integer overflow issues in “backslashreplace”,
     “xmlcharrefreplace”, and “surrogatepass” error handlers.

   - bpo-22540(27): speed up ‘PyObject_IsInstance’ and
     ‘PyObject_IsSubclass’ in the common case that the second argument
     has metaclass ‘type’.

   - bpo-18711(28): Add a new ‘PyErr_FormatV’ function, similar to
     ‘PyErr_Format’ but accepting a ‘va_list’ argument.

   - bpo-22520(29): Fix overflow checking when generating the repr of a
     unicode object.

   - bpo-22519(30): Fix overflow checking in PyBytes_Repr.

   - bpo-22518(31): Fix integer overflow issues in latin-1 encoding.

   - bpo-16324(32): _charset parameter of MIMEText now also accepts
     email.charset.Charset instances.  Initial patch by Claude Paroz.

   - bpo-1764286(33): Fix inspect.getsource() to support decorated
     functions.  Patch by Claudiu Popa.

   - bpo-18554(34): os.__all__ includes posix functions.

   - bpo-21391(35): Use os.path.abspath in the shutil module.

   - bpo-11471(36): avoid generating a JUMP_FORWARD instruction at the
     end of an if-block if there is no else-clause.  Original patch by
     Eugene Toder.

   - bpo-22215(37): Now ValueError is raised instead of TypeError when
     str or bytes argument contains not permitted null character or
     byte.

   - bpo-22258(38): Fix the internal function set_inheritable() on
     Illumos.  This platform exposes the function ‘ioctl(FIOCLEX)’, but
     calling it fails with errno is ENOTTY: “Inappropriate ioctl for
     device”.  set_inheritable() now falls back to the slower ‘fcntl()’
     (‘F_GETFD’ and then ‘F_SETFD’).

   - bpo-21389(39): Displaying the __qualname__ of the underlying
     function in the repr of a bound method.

   - bpo-22206(40): Using pthread, PyThread_create_key() now sets errno
     to ENOMEM and returns -1 (error) on integer overflow.

   - bpo-20184(41): Argument Clinic based signature introspection added
     for 30 of the builtin functions.

   - bpo-22116(42): C functions and methods (of the
     ‘builtin_function_or_method’ type) can now be weakref’ed.  Patch by
     Wei Wu.

   - bpo-22077(43): Improve index error messages for bytearrays, bytes,
     lists, and tuples by adding ‘or slices’.  Added ‘, not <typename>’
     for bytearrays.  Original patch by Claudiu Popa.

   - bpo-20179(44): Apply Argument Clinic to bytes and bytearray.  Patch
     by Tal Einat.

   - bpo-22082(45): Clear interned strings in slotdefs.

   - Upgrade Unicode database to Unicode 7.0.0.

   - bpo-21897(46): Fix a crash with the f_locals attribute with closure
     variables when frame.clear() has been called.

   - bpo-21205(47): Add a new ‘__qualname__’ attribute to generator, the
     qualified name, and use it in the representation of a generator
     (‘repr(gen)’).  The default name of the generator (‘__name__’
     attribute) is now get from the function instead of the code.  Use
     ‘gen.gi_code.co_name’ to get the name of the code.

   - bpo-21669(48): With the aid of heuristics in SyntaxError.__init__,
     the parser now attempts to generate more meaningful (or at least
     more search engine friendly) error messages when “exec” and “print”
     are used as statements.

   - bpo-21642(49): In the conditional if-else expression, allow an
     integer written with no space between itself and the ‘else’ keyword
     (e.g.  ‘True if 42else False’) to be valid syntax.

   - bpo-21523(50): Fix over-pessimistic computation of the stack effect
     of some opcodes in the compiler.  This also fixes a quadratic
     compilation time issue noticeable when compiling code with a large
     number of “and” and “or” operators.

   - bpo-21418(51): Fix a crash in the builtin function super() when
     called without argument and without current frame (ex: embedded
     Python).

   - bpo-21425(52): Fix flushing of standard streams in the interactive
     interpreter.

   - bpo-21435(53): In rare cases, when running finalizers on objects in
     cyclic trash a bad pointer dereference could occur due to a subtle
     flaw in internal iteration logic.

   - bpo-21377(54): PyBytes_Concat() now tries to concatenate in-place
     when the first argument has a reference count of 1.  Patch by
     Nikolaus Rath.

   - bpo-20355(55): -W command line options now have higher priority
     than the PYTHONWARNINGS environment variable.  Patch by Arfrever.

   - bpo-21274(56): Define PATH_MAX for GNU/Hurd in Python/pythonrun.c.

   - bpo-20904(57): Support setting FPU precision on m68k.

   - bpo-21209(58): Fix sending tuples to custom generator objects with
     the yield from syntax.

   - bpo-21193(59): pow(a, b, c) now raises ValueError rather than
     TypeError when b is negative.  Patch by Josh Rosenberg.

   - bpo-21176(60): PEP 465: Add the ‘@’ operator for matrix
     multiplication.

   - bpo-21134(61): Fix segfault when str is called on an uninitialized
     UnicodeEncodeError, UnicodeDecodeError, or UnicodeTranslateError
     object.

   - bpo-19537(62): Fix PyUnicode_DATA() alignment under m68k.  Patch by
     Andreas Schwab.

   - bpo-20929(63): Add a type cast to avoid shifting a negative number.

   - bpo-20731(64): Properly position in source code files even if they
     are opened in text mode.  Patch by Serhiy Storchaka.

   - bpo-20637(65): Key-sharing now also works for instance dictionaries
     of subclasses.  Patch by Peter Ingebretson.

   - bpo-8297(66): Attributes missing from modules now include the
     module name in the error text.  Original patch by ysj.ray.

   - bpo-19995(67): %c, %o, %x, and %X now raise TypeError on
     non-integer input.

   - bpo-19655(68): The ASDL parser - used by the build process to
     generate code for managing the Python AST in C - was rewritten.
     The new parser is self contained and does not require to carry long
     the spark.py parser-generator library; spark.py was removed from
     the source base.

   - bpo-12546(69): Allow ‘\x00’ to be used as a fill character when
     using str, int, float, and complex __format__ methods.

   - bpo-20480(70): Add ipaddress.reverse_pointer.  Patch by Leon Weber.

   - bpo-13598(71): Modify string.Formatter to support auto-numbering of
     replacement fields.  It now matches the behavior of str.format() in
     this regard.  Patches by Phil Elson and Ramchandra Apte.

   - bpo-8931(72): Make alternate formatting (‘#’) for type ‘c’ raise an
     exception.  In versions prior to 3.5, ‘#’ with ‘c’ had no effect.
     Now specifying it is an error.  Patch by Torsten Landschoff.

   - bpo-23165(73): Perform overflow checks before allocating memory in
     the _Py_char2wchar function.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23285

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22735

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22896

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21295

   (5) https://bugs.python.org/issue?@action=redirect&bpo=16795

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22986

   (7) https://bugs.python.org/issue?@action=redirect&bpo=15859

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21408

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23321

   (10) https://bugs.python.org/issue?@action=redirect&bpo=22286

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23253

   (12) https://bugs.python.org/issue?@action=redirect&bpo=22038

   (13) https://bugs.python.org/issue?@action=redirect&bpo=20284

   (14) https://bugs.python.org/issue?@action=redirect&bpo=23048

   (15) https://bugs.python.org/issue?@action=redirect&bpo=20335

   (16) https://bugs.python.org/issue?@action=redirect&bpo=22834

   (17) https://bugs.python.org/issue?@action=redirect&bpo=22869

   (18) https://bugs.python.org/issue?@action=redirect&bpo=22847

   (19) https://bugs.python.org/issue?@action=redirect&bpo=22335

   (20) https://bugs.python.org/issue?@action=redirect&bpo=22653

   (21) https://bugs.python.org/issue?@action=redirect&bpo=22643

   (22) https://bugs.python.org/issue?@action=redirect&bpo=17636

   (23) https://bugs.python.org/issue?@action=redirect&bpo=22604

   (24) https://bugs.python.org/issue?@action=redirect&bpo=21052

   (25) https://bugs.python.org/issue?@action=redirect&bpo=16518

   (26) https://bugs.python.org/issue?@action=redirect&bpo=22470

   (27) https://bugs.python.org/issue?@action=redirect&bpo=22540

   (28) https://bugs.python.org/issue?@action=redirect&bpo=18711

   (29) https://bugs.python.org/issue?@action=redirect&bpo=22520

   (30) https://bugs.python.org/issue?@action=redirect&bpo=22519

   (31) https://bugs.python.org/issue?@action=redirect&bpo=22518

   (32) https://bugs.python.org/issue?@action=redirect&bpo=16324

   (33) https://bugs.python.org/issue?@action=redirect&bpo=1764286

   (34) https://bugs.python.org/issue?@action=redirect&bpo=18554

   (35) https://bugs.python.org/issue?@action=redirect&bpo=21391

   (36) https://bugs.python.org/issue?@action=redirect&bpo=11471

   (37) https://bugs.python.org/issue?@action=redirect&bpo=22215

   (38) https://bugs.python.org/issue?@action=redirect&bpo=22258

   (39) https://bugs.python.org/issue?@action=redirect&bpo=21389

   (40) https://bugs.python.org/issue?@action=redirect&bpo=22206

   (41) https://bugs.python.org/issue?@action=redirect&bpo=20184

   (42) https://bugs.python.org/issue?@action=redirect&bpo=22116

   (43) https://bugs.python.org/issue?@action=redirect&bpo=22077

   (44) https://bugs.python.org/issue?@action=redirect&bpo=20179

   (45) https://bugs.python.org/issue?@action=redirect&bpo=22082

   (46) https://bugs.python.org/issue?@action=redirect&bpo=21897

   (47) https://bugs.python.org/issue?@action=redirect&bpo=21205

   (48) https://bugs.python.org/issue?@action=redirect&bpo=21669

   (49) https://bugs.python.org/issue?@action=redirect&bpo=21642

   (50) https://bugs.python.org/issue?@action=redirect&bpo=21523

   (51) https://bugs.python.org/issue?@action=redirect&bpo=21418

   (52) https://bugs.python.org/issue?@action=redirect&bpo=21425

   (53) https://bugs.python.org/issue?@action=redirect&bpo=21435

   (54) https://bugs.python.org/issue?@action=redirect&bpo=21377

   (55) https://bugs.python.org/issue?@action=redirect&bpo=20355

   (56) https://bugs.python.org/issue?@action=redirect&bpo=21274

   (57) https://bugs.python.org/issue?@action=redirect&bpo=20904

   (58) https://bugs.python.org/issue?@action=redirect&bpo=21209

   (59) https://bugs.python.org/issue?@action=redirect&bpo=21193

   (60) https://bugs.python.org/issue?@action=redirect&bpo=21176

   (61) https://bugs.python.org/issue?@action=redirect&bpo=21134

   (62) https://bugs.python.org/issue?@action=redirect&bpo=19537

   (63) https://bugs.python.org/issue?@action=redirect&bpo=20929

   (64) https://bugs.python.org/issue?@action=redirect&bpo=20731

   (65) https://bugs.python.org/issue?@action=redirect&bpo=20637

   (66) https://bugs.python.org/issue?@action=redirect&bpo=8297

   (67) https://bugs.python.org/issue?@action=redirect&bpo=19995

   (68) https://bugs.python.org/issue?@action=redirect&bpo=19655

   (69) https://bugs.python.org/issue?@action=redirect&bpo=12546

   (70) https://bugs.python.org/issue?@action=redirect&bpo=20480

   (71) https://bugs.python.org/issue?@action=redirect&bpo=13598

   (72) https://bugs.python.org/issue?@action=redirect&bpo=8931

   (73) https://bugs.python.org/issue?@action=redirect&bpo=23165


File: python.info,  Node: Library<183>,  Next: IDLE<67>,  Prev: Core and Builtins<181>,  Up: Python 3 5 0 alpha 1

1.23.121.2 Library
..................

   - bpo-23399(1): pyvenv creates relative symlinks where possible.

   - bpo-20289(2): cgi.FieldStorage() now supports the context
     management protocol.

   - bpo-13128(3): Print response headers for CONNECT requests when
     debuglevel > 0.  Patch by Demian Brecht.

   - bpo-15381(4): Optimized io.BytesIO to make less allocations and
     copyings.

   - bpo-22818(5): Splitting on a pattern that could match an empty
     string now raises a warning.  Patterns that can only match empty
     strings are now rejected.

   - bpo-23099(6): Closing io.BytesIO with exported buffer is rejected
     now to prevent corrupting exported buffer.

   - bpo-23326(7): Removed __ne__ implementations.  Since fixing default
     __ne__ implementation in bpo-21408(8) they are redundant.

   - bpo-23363(9): Fix possible overflow in itertools.permutations.

   - bpo-23364(10): Fix possible overflow in itertools.product.

   - bpo-23366(11): Fixed possible integer overflow in
     itertools.combinations.

   - bpo-23369(12): Fixed possible integer overflow in
     _json.encode_basestring_ascii.

   - bpo-23353(13): Fix the exception handling of generators in
     PyEval_EvalFrameEx().  At entry, save or swap the exception state
     even if PyEval_EvalFrameEx() is called with throwflag=0.  At exit,
     the exception state is now always restored or swapped, not only if
     why is WHY_YIELD or WHY_RETURN. Patch co-written with Antoine
     Pitrou.

   - bpo-14099(14): Restored support of writing ZIP files to tellable
     but non-seekable streams.

   - bpo-14099(15): Writing to ZipFile and reading multiple ZipExtFiles
     is threadsafe now.

   - bpo-19361(16): JSON decoder now raises JSONDecodeError instead of
     ValueError.

   - bpo-18518(17): timeit now rejects statements which can’t be
     compiled outside a function or a loop (e.g.  “return” or “break”).

   - bpo-23094(18): Fixed readline with frames in Python implementation
     of pickle.

   - bpo-23268(19): Fixed bugs in the comparison of ipaddress classes.

   - bpo-21408(20): Removed incorrect implementations of __ne__() which
     didn’t returned NotImplemented if __eq__() returned NotImplemented.
     The default __ne__() now works correctly.

   - bpo-19996(21): ‘email.feedparser.FeedParser’ now handles
     (malformed) headers with no key rather than assuming the body has
     started.

   - bpo-20188(22): Support Application-Layer Protocol Negotiation
     (ALPN) in the ssl module.

   - bpo-23133(23): Pickling of ipaddress objects now produces more
     compact and portable representation.

   - bpo-23248(24): Update ssl error codes from latest OpenSSL git
     master.

   - bpo-23266(25): Much faster implementation of
     ipaddress.collapse_addresses() when there are many non-consecutive
     addresses.

   - bpo-23098(26): 64-bit dev_t is now supported in the os module.

   - bpo-21817(27): When an exception is raised in a task submitted to a
     ProcessPoolExecutor, the remote traceback is now displayed in the
     parent process.  Patch by Claudiu Popa.

   - bpo-15955(28): Add an option to limit output size when
     decompressing LZMA data.  Patch by Nikolaus Rath and Martin Panter.

   - bpo-23250(29): In the http.cookies module, capitalize “HttpOnly”
     and “Secure” as they are written in the standard.

   - bpo-23063(30): In the distutils’ check command, fix parsing of reST
     with code or code-block directives.

   - bpo-23209(31): selectors.BaseSelector.get_key() now raises a
     RuntimeError if the selector is closed.  And
     selectors.BaseSelector.close() now clears its internal reference to
     the selector mapping to break a reference cycle.  Initial patch
     written by Martin Richard.  (See also: bpo-23225(32))

   - bpo-17911(33): Provide a way to seed the linecache for a PEP-302
     module without actually loading the code.

   - bpo-17911(34): Provide a new object API for traceback, including
     the ability to not lookup lines at all until the traceback is
     actually rendered, without any trace of the original objects being
     kept alive.

   - bpo-19777(35): Provide a home() classmethod on Path objects.
     Contributed by Victor Salgado and Mayank Tripathi.

   - bpo-23206(36): Make ‘json.dumps(..., ensure_ascii=False)’ as fast
     as the default case of ‘ensure_ascii=True’.  Patch by Naoki Inada.

   - bpo-23185(37): Add math.inf and math.nan constants.

   - bpo-23186(38): Add ssl.SSLObject.shared_ciphers() and
     ssl.SSLSocket.shared_ciphers() to fetch the client’s list ciphers
     sent at handshake.

   - bpo-23143(39): Remove compatibility with OpenSSLs older than 0.9.8.

   - bpo-23132(40): Improve performance and introspection support of
     comparison methods created by functool.total_ordering.

   - bpo-19776(41): Add an expanduser() method on Path objects.

   - bpo-23112(42): Fix SimpleHTTPServer to correctly carry the query
     string and fragment when it redirects to add a trailing slash.

   - bpo-21793(43): Added http.HTTPStatus enums (i.e.  HTTPStatus.OK,
     HTTPStatus.NOT_FOUND). Patch by Demian Brecht.

   - bpo-23093(44): In the io, module allow more operations to work on
     detached streams.

   - bpo-23111(45): In the ftplib, make ssl.PROTOCOL_SSLv23 the default
     protocol version.

   - bpo-22585(46): On OpenBSD 5.6 and newer, os.urandom() now calls
     getentropy(), instead of reading /dev/urandom, to get pseudo-random
     bytes.

   - bpo-19104(47): pprint now produces evaluable output for wrapped
     strings.

   - bpo-23071(48): Added missing names to codecs.__all__.  Patch by
     Martin Panter.

   - bpo-22783(49): Pickling now uses the NEWOBJ opcode instead of the
     NEWOBJ_EX opcode if possible.

   - bpo-15513(50): Added a __sizeof__ implementation for pickle
     classes.

   - bpo-19858(51): pickletools.optimize() now aware of the MEMOIZE
     opcode, can produce more compact result and no longer produces
     invalid output if input data contains MEMOIZE opcodes together with
     PUT or BINPUT opcodes.

   - bpo-22095(52): Fixed HTTPConnection.set_tunnel with default port.
     The port value in the host header was set to “None”.  Patch by
     Demian Brecht.

   - bpo-23016(53): A warning no longer produces an AttributeError when
     the program is run with pythonw.exe.

   - bpo-21775(54): shutil.copytree(): fix crash when copying to VFAT.
     An exception handler assumed that OSError objects always have a
     ‘winerror’ attribute.  That is not the case, so the exception
     handler itself raised AttributeError when run on Linux (and,
     presumably, any other non-Windows OS). Patch by Greg Ward.

   - bpo-1218234(55): Fix inspect.getsource() to load updated source of
     reloaded module.  Initial patch by Berker Peksag.

   - bpo-21740(56): Support wrapped callables in doctest.  Patch by
     Claudiu Popa.

   - bpo-23009(57): Make sure selectors.EpollSelector.select() works
     when no FD is registered.

   - bpo-22959(58): In the constructor of http.client.HTTPSConnection,
     prefer the context’s check_hostname attribute over the
     'check_hostname' parameter.

   - bpo-22696(59): Add function *note sys.is_finalizing(): a9e. to know
     about interpreter shutdown.

   - bpo-16043(60): Add a default limit for the amount of data
     xmlrpclib.gzip_decode will return.  This resolves CVE
     2013-1753(61).

   - bpo-14099(62): ZipFile.open() no longer reopen the underlying file.
     Objects returned by ZipFile.open() can now operate independently of
     the ZipFile even if the ZipFile was created by passing in a
     file-like object as the first argument to the constructor.

   - bpo-22966(63): Fix __pycache__ pyc file name clobber when
     pyc_compile is asked to compile a source file containing multiple
     dots in the source file name.

   - bpo-21971(64): Update turtledemo doc and add module to the index.

   - bpo-21032(65): Fixed socket leak if HTTPConnection.getresponse()
     fails.  Original patch by Martin Panter.

   - bpo-22407(66): Deprecated the use of re.LOCALE flag with str
     patterns or re.ASCII. It was newer worked.

   - bpo-22902(67): The “ip” command is now used on Linux to determine
     MAC address in uuid.getnode().  Pach by Bruno Cauet.

   - bpo-22960(68): Add a context argument to xmlrpclib.ServerProxy
     constructor.

   - bpo-22389(69): Add contextlib.redirect_stderr().

   - bpo-21356(70): Make ssl.RAND_egd() optional to support LibreSSL.
     The availability of the function is checked during the compilation.
     Patch written by Bernard Spil.

   - bpo-22915(71): SAX parser now supports files opened with file
     descriptor or bytes path.

   - bpo-22609(72): Constructors and update methods of mapping classes
     in the collections module now accept the self keyword argument.

   - bpo-22940(73): Add readline.append_history_file.

   - bpo-19676(74): Added the “namereplace” error handler.

   - bpo-22788(75): Add 'context' parameter to
     logging.handlers.HTTPHandler.

   - bpo-22921(76): Allow SSLContext to take the 'hostname' parameter
     even if OpenSSL doesn’t support SNI.

   - bpo-22894(77): TestCase.subTest() would cause the test suite to be
     stopped when in failfast mode, even in the absence of failures.

   - bpo-22796(78): HTTP cookie parsing is now stricter, in order to
     protect against potential injection attacks.

   - bpo-22370(79): Windows detection in pathlib is now more robust.

   - bpo-22841(80): Reject coroutines in asyncio add_signal_handler().
     Patch by Ludovic.Gasc.

   - bpo-19494(81): Added urllib.request.HTTPBasicPriorAuthHandler.
     Patch by Matej Cepl.

   - bpo-22578(82): Added attributes to the re.error class.

   - bpo-22849(83): Fix possible double free in the io.TextIOWrapper
     constructor.

   - bpo-12728(84): Different Unicode characters having the same
     uppercase but different lowercase are now matched in
     case-insensitive regular expressions.

   - bpo-22821(85): Fixed fcntl() with integer argument on 64-bit
     big-endian platforms.

   - bpo-21650(86): Add an ‘--sort-keys’ option to ‘json.tool’ CLI.

   - bpo-22824(87): Updated reprlib output format for sets to use set
     literals.  Patch contributed by Berker Peksag.

   - bpo-22824(88): Updated reprlib output format for arrays to display
     empty arrays without an unnecessary empty list.  Suggested by
     Serhiy Storchaka.

   - bpo-22406(89): Fixed the uu_codec codec incorrectly ported to 3.x.
     Based on patch by Martin Panter.

   - bpo-17293(90): uuid.getnode() now determines MAC address on AIX
     using netstat.  Based on patch by Aivars Kalvāns.

   - bpo-22769(91): Fixed ttk.Treeview.tag_has() when called without
     arguments.

   - bpo-22417(92): Verify certificates by default in httplib (PEP 476).

   - bpo-22775(93): Fixed unpickling of http.cookies.SimpleCookie with
     protocol 2 and above.  Patch by Tim Graham.

   - bpo-22776(94): Brought excluded code into the scope of a try block
     in SysLogHandler.emit().

   - bpo-22665(95): Add missing get_terminal_size and SameFileError to
     shutil.__all__.

   - bpo-6623(96): Remove deprecated Netrc class in the ftplib module.
     Patch by Matt Chaput.

   - bpo-17381(97): Fixed handling of case-insensitive ranges in regular
     expressions.

   - bpo-22410(98): Module level functions in the re module now cache
     compiled locale-dependent regular expressions taking into account
     the locale.

   - bpo-22759(99): Query methods on pathlib.Path() (exists(), is_dir(),
     etc.)  now return False when the underlying stat call raises
     NotADirectoryError.

   - bpo-8876(100): distutils now falls back to copying files when hard
     linking doesn’t work.  This allows use with special filesystems
     such as VirtualBox shared folders.

   - bpo-22217(101): Implemented reprs of classes in the zipfile module.

   - bpo-22457(102): Honour load_tests in the start_dir of discovery.

   - bpo-18216(103): gettext now raises an error when a .mo file has an
     unsupported major version number.  Patch by Aaron Hill.

   - bpo-13918(104): Provide a locale.delocalize() function which can
     remove locale-specific number formatting from a string representing
     a number, without then converting it to a specific type.  Patch by
     Cédric Krier.

   - bpo-22676(105): Make the pickling of global objects which don’t
     have a __module__ attribute less slow.

   - bpo-18853(106): Fixed ResourceWarning in shlex.__nain__.

   - bpo-9351(107): Defaults set with set_defaults on an argparse
     subparser are no longer ignored when also set on the parent parser.

   - bpo-7559(108): unittest test loading ImportErrors are reported as
     import errors with their import exception rather than as attribute
     errors after the import has already failed.

   - bpo-19746(109): Make it possible to examine the errors from
     unittest discovery without executing the test suite.  The new
     ‘errors’ attribute on ‘TestLoader’ exposes these non-fatal errors
     encountered during discovery.

   - bpo-21991(110): Make email.headerregistry’s header ‘params’
     attributes be read-only (MappingProxyType).  Previously the
     dictionary was modifiable but a new one was created on each access
     of the attribute.

   - bpo-22638(111): SSLv3 is now disabled throughout the standard
     library.  It can still be enabled by instantiating a SSLContext
     manually.

   - bpo-22641(112): In asyncio, the default SSL context for client
     connections is now created using ssl.create_default_context(), for
     stronger security.

   - bpo-17401(113): Include closefd in io.FileIO repr.

   - bpo-21338(114): Add silent mode for compileall.  quiet parameters
     of compile_{dir, file, path} functions now have a multilevel value.
     Also, -q option of the CLI now have a multilevel value.  Patch by
     Thomas Kluyver.

   - bpo-20152(115): Convert the array and cmath modules to Argument
     Clinic.

   - bpo-18643(116): Add socket.socketpair() on Windows.

   - bpo-22435(117): Fix a file descriptor leak when socketserver bind
     fails.

   - bpo-13096(118): Fixed segfault in CTypes POINTER handling of large
     values.

   - bpo-11694(119): Raise ConversionError in xdrlib as documented.
     Patch by Filip Gruszczyński and Claudiu Popa.

   - bpo-19380(120): Optimized parsing of regular expressions.

   - bpo-1519638(121): Now unmatched groups are replaced with empty
     strings in re.sub() and re.subn().

   - bpo-18615(122): sndhdr.what/whathdr now return a namedtuple.

   - bpo-22462(123): Fix pyexpat’s creation of a dummy frame to make it
     appear in exception tracebacks.

   - bpo-21965(124): Add support for in-memory SSL to the ssl module.
     Patch by Geert Jansen.

   - bpo-21173(125): Fix len() on a WeakKeyDictionary when .clear() was
     called with an iterator alive.

   - bpo-11866(126): Eliminated race condition in the computation of
     names for new threads.

   - bpo-21905(127): Avoid RuntimeError in pickle.whichmodule() when
     sys.modules is mutated while iterating.  Patch by Olivier Grisel.

   - bpo-11271(128): concurrent.futures.Executor.map() now takes a
     'chunksize' argument to allow batching of tasks in child processes
     and improve performance of ProcessPoolExecutor.  Patch by Dan
     O’Reilly.

   - bpo-21883(129): os.path.join() and os.path.relpath() now raise a
     TypeError with more helpful error message for unsupported or
     mismatched types of arguments.

   - bpo-22219(130): The zipfile module CLI now adds entries for
     directories (including empty directories) in ZIP file.

   - bpo-22449(131): In the ssl.SSLContext.load_default_certs, consult
     the environmental variables SSL_CERT_DIR and SSL_CERT_FILE on
     Windows.

   - bpo-22508(132): The email.__version__ variable has been removed;
     the email code is no longer shipped separately from the stdlib, and
     __version__ hasn’t been updated in several releases.

   - bpo-20076(133): Added non derived UTF-8 aliases to locale aliases
     table.

   - bpo-20079(134): Added locales supported in glibc 2.18 to locale
     alias table.

   - bpo-20218(135): Added convenience methods read_text/write_text and
     read_bytes/ write_bytes to pathlib.Path objects.

   - bpo-22396(136): On 32-bit AIX platform, don’t expose
     os.posix_fadvise() nor os.posix_fallocate() because their
     prototypes in system headers are wrong.

   - bpo-22517(137): When an io.BufferedRWPair object is deallocated,
     clear its weakrefs.

   - bpo-22437(138): Number of capturing groups in regular expression is
     no longer limited by 100.

   - bpo-17442(139): InteractiveInterpreter now displays the full
     chained traceback in its showtraceback method, to match the built
     in interactive interpreter.

   - bpo-23392(140): Added tests for marshal C API that works with
     FILE*.

   - bpo-10510(141): distutils register and upload methods now use HTML
     standards compliant CRLF line endings.

   - bpo-9850(142): Fixed macpath.join() for empty first component.
     Patch by Oleg Oshmyan.

   - bpo-5309(143): distutils’ build and build_ext commands now accept a
     ‘-j’ option to enable parallel building of extension modules.

   - bpo-22448(144): Improve canceled timer handles cleanup to prevent
     unbound memory usage.  Patch by Joshua Moore-Oliva.

   - bpo-22427(145): TemporaryDirectory no longer attempts to clean up
     twice when used in the with statement in generator.

   - bpo-22362(146): Forbidden ambiguous octal escapes out of range
     0-0o377 in regular expressions.

   - bpo-20912(147): Now directories added to ZIP file have correct Unix
     and MS-DOS directory attributes.

   - bpo-21866(148): ZipFile.close() no longer writes ZIP64 central
     directory records if allowZip64 is false.

   - bpo-22278(149): Fix urljoin problem with relative urls, a
     regression observed after changes to issue22118 were submitted.

   - bpo-22415(150): Fixed debugging output of the GROUPREF_EXISTS
     opcode in the re module.  Removed trailing spaces in debugging
     output.

   - bpo-22423(151): Unhandled exception in thread no longer causes
     unhandled AttributeError when sys.stderr is None.

   - bpo-21332(152): Ensure that ‘bufsize=1’ in subprocess.Popen()
     selects line buffering, rather than block buffering.  Patch by
     Akira Li.

   - bpo-21091(153): Fix API bug:
     email.message.EmailMessage.is_attachment is now a method.

   - bpo-21079(154): Fix email.message.EmailMessage.is_attachment to
     return the correct result when the header has parameters as well as
     a value.

   - bpo-22247(155): Add NNTPError to nntplib.__all__.

   - bpo-22366(156): urllib.request.urlopen will accept a context object
     (SSLContext) as an argument which will then be used for HTTPS
     connection.  Patch by Alex Gaynor.

   - bpo-4180(157): The warnings registries are now reset when the
     filters are modified.

   - bpo-22419(158): Limit the length of incoming HTTP request in
     wsgiref server to 65536 bytes and send a 414 error code for higher
     lengths.  Patch contributed by Devin Cook.

   - Lax cookie parsing in http.cookies could be a security issue when
     combined with non-standard cookie handling in some web browsers.
     Reported by Sergey Bobrov.

   - bpo-20537(159): logging methods now accept an exception instance as
     well as a Boolean value or exception tuple.  Thanks to Yury
     Selivanov for the patch.

   - bpo-22384(160): An exception in Tkinter callback no longer crashes
     the program when it is run with pythonw.exe.

   - bpo-22168(161): Prevent turtle AttributeError with non-default
     Canvas on OS X.

   - bpo-21147(162): sqlite3 now raises an exception if the request
     contains a null character instead of truncating it.  Based on patch
     by Victor Stinner.

   - bpo-13968(163): The glob module now supports recursive search in
     subdirectories using the ‘**’ pattern.

   - bpo-21951(164): Fixed a crash in Tkinter on AIX when called Tcl
     command with empty string or tuple argument.

   - bpo-21951(165): Tkinter now most likely raises MemoryError instead
     of crash if the memory allocation fails.

   - bpo-22338(166): Fix a crash in the json module on memory allocation
     failure.

   - bpo-12410(167): imaplib.IMAP4 now supports the context management
     protocol.  Original patch by Tarek Ziadé.

   - bpo-21270(168): We now override tuple methods in mock.call objects
     so that they can be used as normal call attributes.

   - bpo-16662(169): ‘load_tests()’ is now unconditionally run when it
     is present in a package’s ‘__init__.py’.
     ‘TestLoader.loadTestsFromModule()’ still accepts use_load_tests,
     but it is deprecated and ignored.  A new keyword-only attribute
     ‘pattern’ is added and documented.  Patch given by Robert Collins,
     tweaked by Barry Warsaw.

   - bpo-22226(170): First letter no longer is stripped from the
     “status” key in the result of Treeview.heading().

   - bpo-19524(171): Fixed resource leak in the HTTP connection when an
     invalid response is received.  Patch by Martin Panter.

   - bpo-20421(172): Add a .version() method to SSL sockets exposing the
     actual protocol version in use.

   - bpo-19546(173): configparser exceptions no longer expose
     implementation details.  Chained KeyErrors are removed, which leads
     to cleaner tracebacks.  Patch by Claudiu Popa.

   - bpo-22051(174): turtledemo no longer reloads examples to re-run
     them.  Initialization of variables and gui setup should be done in
     main(), which is called each time a demo is run, but not on import.

   - bpo-21933(175): Turtledemo users can change the code font size with
     a menu selection or control(command) ‘-’ or ‘+’ or
     control-mousewheel.  Original patch by Lita Cho.

   - bpo-21597(176): The separator between the turtledemo text pane and
     the drawing canvas can now be grabbed and dragged with a mouse.
     The code text pane can be widened to easily view or copy the full
     width of the text.  The canvas can be widened on small screens.
     Original patches by Jan Kanis and Lita Cho.

   - bpo-18132(177): Turtledemo buttons no longer disappear when the
     window is shrunk.  Original patches by Jan Kanis and Lita Cho.

   - bpo-22043(178): time.monotonic() is now always available.
     ‘threading.Lock.acquire()’, ‘threading.RLock.acquire()’ and socket
     operations now use a monotonic clock, instead of the system clock,
     when a timeout is used.

   - bpo-21527(179): Add a default number of workers to
     ThreadPoolExecutor equal to 5 times the number of CPUs.  Patch by
     Claudiu Popa.

   - bpo-22216(180): smtplib now resets its state more completely after
     a quit.  The most obvious consequence of the previous behavior was
     a STARTTLS failure during a connect/starttls/quit/connect/starttls
     sequence.

   - bpo-22098(181): ctypes’ BigEndianStructure and
     LittleEndianStructure now define an empty __slots__ so that
     subclasses don’t always get an instance dict.  Patch by Claudiu
     Popa.

   - bpo-22185(182): Fix an occasional RuntimeError in
     threading.Condition.wait() caused by mutation of the waiters queue
     without holding the lock.  Patch by Doug Zongker.

   - bpo-22287(183): On UNIX, _PyTime_gettimeofday() now uses
     clock_gettime(CLOCK_REALTIME) if available.  As a side effect,
     Python now depends on the librt library on Solaris and on Linux
     (only with glibc older than 2.17).

   - bpo-22182(184): Use e.args to unpack exceptions correctly in
     distutils.file_util.move_file.  Patch by Claudiu Popa.

   - The webbrowser module now uses subprocess’s start_new_session=True
     rather than a potentially risky preexec_fn=os.setsid call.

   - bpo-22042(185): signal.set_wakeup_fd(fd) now raises an exception if
     the file descriptor is in blocking mode.

   - bpo-16808(186): inspect.stack() now returns a named tuple instead
     of a tuple.  Patch by Daniel Shahaf.

   - bpo-22236(187): Fixed Tkinter images copying operations in
     NoDefaultRoot mode.

   - bpo-2527(188): Add a 'globals' argument to timeit functions, in
     order to override the globals namespace in which the timed code is
     executed.  Patch by Ben Roberts.

   - bpo-22118(189): Switch urllib.parse to use RFC 3986 semantics for
     the resolution of relative URLs, rather than RFCs 1808 and 2396.
     Patch by Demian Brecht.

   - bpo-21549(190): Added the “members” parameter to TarFile.list().

   - bpo-19628(191): Allow compileall recursion depth to be specified
     with a -r option.

   - bpo-15696(192): Add a __sizeof__ implementation for mmap objects on
     Windows.

   - bpo-22068(193): Avoided reference loops with Variables and Fonts in
     Tkinter.

   - bpo-22165(194): SimpleHTTPRequestHandler now supports undecodable
     file names.

   - bpo-15381(195): Optimized line reading in io.BytesIO.

   - bpo-8797(196): Raise HTTPError on failed Basic Authentication
     immediately.  Initial patch by Sam Bull.

   - bpo-20729(197): Restored the use of lazy
     iterkeys()/itervalues()/iteritems() in the mailbox module.

   - bpo-21448(198): Changed FeedParser feed() to avoid 'O'('n'^2)
     behavior when parsing long line.  Original patch by Raymond
     Hettinger.

   - bpo-22184(199): The functools LRU Cache decorator factory now gives
     an earlier and clearer error message when the user forgets the
     required parameters.

   - bpo-17923(200): glob() patterns ending with a slash no longer match
     non-dirs on AIX. Based on patch by Delhallt.

   - bpo-21725(201): Added support for RFC 6531 (SMTPUTF8) in smtpd.

   - bpo-22176(202): Update the ctypes module’s libffi to v3.1.  This
     release adds support for the Linux AArch64 and POWERPC ELF ABIv2
     little endian architectures.

   - bpo-5411(203): Added support for the “xztar” format in the shutil
     module.

   - bpo-21121(204): Don’t force 3rd party C extensions to be built with
     -Werror=declaration-after-statement.

   - bpo-21975(205): Fixed crash when using uninitialized sqlite3.Row
     (in particular when unpickling pickled sqlite3.Row).  sqlite3.Row
     is now initialized in the __new__() method.

   - bpo-20170(206): Convert posixmodule to use Argument Clinic.

   - bpo-21539(207): Add an 'exists_ok' argument to ‘Pathlib.mkdir()’ to
     mimic ‘mkdir -p’ and ‘os.makedirs()’ functionality.  When true,
     ignore ‘FileExistsErrors’.  Patch by Berker Peksag.

   - bpo-22127(208): Bypass IDNA for pure-ASCII host names in the socket
     module (in particular for numeric IPs).

   - bpo-21047(209): set the default value for the 'convert_charrefs'
     argument of HTMLParser to True.  Patch by Berker Peksag.

   - Add an __all__ to html.entities.

   - bpo-15114(210): the strict mode and argument of HTMLParser,
     HTMLParser.error, and the HTMLParserError exception have been
     removed.

   - bpo-22085(211): Dropped support of Tk 8.3 in Tkinter.

   - bpo-21580(212): Now Tkinter correctly handles bytes arguments
     passed to Tk.  In particular this allows initializing images from
     binary data.

   - bpo-22003(213): When initialized from a bytes object, io.BytesIO()
     now defers making a copy until it is mutated, improving performance
     and memory use on some use cases.  Patch by David Wilson.

   - bpo-22018(214): On Windows, signal.set_wakeup_fd() now also
     supports sockets.  A side effect is that Python depends to the
     WinSock library.

   - bpo-22054(215): Add os.get_blocking() and os.set_blocking()
     functions to get and set the blocking mode of a file descriptor
     (False if the O_NONBLOCK flag is set, True otherwise).  These
     functions are not available on Windows.

   - bpo-17172(216): Make turtledemo start as active on OS X even when
     run with subprocess.  Patch by Lita Cho.

   - bpo-21704(217): Fix build error for _multiprocessing when
     semaphores are not available.  Patch by Arfrever Frehtes Taifersar
     Arahesis.

   - bpo-20173(218): Convert sha1, sha256, sha512 and md5 to
     ArgumentClinic.  Patch by Vajrasky Kok.

   - Fix repr(_socket.socket) on Windows 64-bit: don’t fail with
     OverflowError on closed socket.  repr(socket.socket) already works
     fine.

   - bpo-22033(219): Reprs of most Python implemented classes now
     contain actual class name instead of hardcoded one.

   - bpo-21947(220): The dis module can now disassemble
     generator-iterator objects based on their gi_code attribute.  Patch
     by Clement Rouault.

   - bpo-16133(221): The asynchat.async_chat.handle_read() method now
     ignores BlockingIOError exceptions.

   - bpo-22044(222): Fixed premature DECREF in call_tzinfo_method.
     Patch by Tom Flanagan.

   - bpo-19884(223): readline: Disable the meta modifier key if stdout
     is not a terminal to not write the ANSI sequence ‘"\033[1034h"’
     into stdout.  This sequence is used on some terminal (ex:
     TERM=xterm-256color”) to enable support of 8 bit characters.

   - bpo-4350(224): Removed a number of out-of-dated and non-working for
     a long time Tkinter methods.

   - bpo-6167(225): Scrollbar.activate() now returns the name of active
     element if the argument is not specified.  Scrollbar.set() now
     always accepts only 2 arguments.

   - bpo-15275(226): Clean up and speed up the ntpath module.

   - bpo-21888(227): plistlib’s load() and loads() now work if the fmt
     parameter is specified.

   - bpo-22032(228): __qualname__ instead of __name__ is now always used
     to format fully qualified class names of Python implemented
     classes.

   - bpo-22031(229): Reprs now always use hexadecimal format with the
     “0x” prefix when contain an id in form “ at 0x…”.

   - bpo-22018(230): signal.set_wakeup_fd() now raises an OSError
     instead of a ValueError on ‘fstat()’ failure.

   - bpo-21044(231): tarfile.open() now handles fileobj with an integer
     ‘name’ attribute.  Based on patch by Antoine Pietri.

   - bpo-21966(232): Respect -q command-line option when code module is
     ran.

   - bpo-19076(233): Don’t pass the redundant ‘file’ argument to
     self.error().

   - bpo-16382(234): Improve exception message of warnings.warn() for
     bad category.  Initial patch by Phil Elson.

   - bpo-21932(235): os.read() now uses a *note Py_ssize_t(): a6e. type
     instead of int for the size to support reading more than 2 GB at
     once.  On Windows, the size is truncated to INT_MAX. As any call to
     os.read(), the OS may read less bytes than the number of requested
     bytes.

   - bpo-21942(236): Fixed source file viewing in pydoc’s server mode on
     Windows.

   - bpo-11259(237): asynchat.async_chat().set_terminator() now raises a
     ValueError if the number of received bytes is negative.

   - bpo-12523(238): asynchat.async_chat.push() now raises a TypeError
     if it doesn’t get a bytes string

   - bpo-21707(239): Add missing kwonlyargcount argument to
     ModuleFinder.replace_paths_in_code().

   - bpo-20639(240): calling Path.with_suffix(‘’) allows removing the
     suffix again.  Patch by July Tikhonov.

   - bpo-21714(241): Disallow the construction of invalid paths using
     Path.with_name().  Original patch by Antony Lee.

   - bpo-15014(242): Added ‘auth’ method to smtplib to make implementing
     auth mechanisms simpler, and used it internally in the login
     method.

   - bpo-21151(243): Fixed a segfault in the winreg module when ‘None’
     is passed as a ‘REG_BINARY’ value to SetValueEx.  Patch by John
     Ehresman.

   - bpo-21090(244): io.FileIO.readall() does not ignore I/O errors
     anymore.  Before, it ignored I/O errors if at least the first C
     call read() succeed.

   - bpo-5800(245): headers parameter of wsgiref.headers.Headers is now
     optional.  Initial patch by Pablo Torres Navarrete and SilentGhost.

   - bpo-21781(246): ssl.RAND_add() now supports strings longer than 2
     GB.

   - bpo-21679(247): Prevent extraneous fstat() calls during open().
     Patch by Bohuslav Kabrda.

   - bpo-21863(248): cProfile now displays the module name of C
     extension functions, in addition to their own name.

   - bpo-11453(249): asyncore: emit a ResourceWarning when an unclosed
     file_wrapper object is destroyed.  The destructor now closes the
     file if needed.  The close() method can now be called twice: the
     second call does nothing.

   - bpo-21858(250): Better handling of Python exceptions in the sqlite3
     module.

   - bpo-21476(251): Make sure the email.parser.BytesParser
     TextIOWrapper is discarded after parsing, so the input file isn’t
     unexpectedly closed.

   - bpo-20295(252): imghdr now recognizes OpenEXR format images.

   - bpo-21729(253): Used the “with” statement in the dbm.dumb module to
     ensure files closing.  Patch by Claudiu Popa.

   - bpo-21491(254): socketserver: Fix a race condition in child
     processes reaping.

   - bpo-21719(255): Added the ‘st_file_attributes’ field to
     os.stat_result on Windows.

   - bpo-21832(256): Require named tuple inputs to be exact strings.

   - bpo-21722(257): The distutils “upload” command now exits with a
     non-zero return code when uploading fails.  Patch by Martin
     Dengler.

   - bpo-21723(258): asyncio.Queue: support any type of number (ex:
     float) for the maximum size.  Patch written by Vajrasky Kok.

   - bpo-21711(259): support for “site-python” directories has now been
     removed from the site module (it was deprecated in 3.4).

   - bpo-17552(260): new socket.sendfile() method allowing a file to be
     sent over a socket by using high-performance os.sendfile() on UNIX.
     Patch by Giampaolo Rodola’.

   - bpo-18039(261): dbm.dump.open() now always creates a new database
     when the flag has the value ‘n’.  Patch by Claudiu Popa.

   - bpo-21326(262): Add a new is_closed() method to
     asyncio.BaseEventLoop.  run_forever() and run_until_complete()
     methods of asyncio.BaseEventLoop now raise an exception if the
     event loop was closed.

   - bpo-21766(263): Prevent a security hole in CGIHTTPServer by URL
     unquoting paths before checking for a CGI script at that path.

   - bpo-21310(264): Fixed possible resource leak in failed open().

   - bpo-21256(265): Printout of keyword args should be in deterministic
     order in a mock function call.  This will help to write better
     doctests.

   - bpo-21677(266): Fixed chaining nonnormalized exceptions in io
     close() methods.

   - bpo-11709(267): Fix the pydoc.help function to not fail when
     sys.stdin is not a valid file.

   - bpo-21515(268): tempfile.TemporaryFile now uses os.O_TMPFILE flag
     is available.

   - bpo-13223(269): Fix pydoc.writedoc so that the HTML documentation
     for methods that use ‘self’ in the example code is generated
     correctly.

   - bpo-21463(270): In urllib.request, fix pruning of the FTP cache.

   - bpo-21618(271): The subprocess module could fail to close open fds
     that were inherited by the calling process and already higher than
     POSIX resource limits would otherwise allow.  On systems with a
     functioning /proc/self/fd or /dev/fd interface the max is now
     ignored and all fds are closed.

   - bpo-20383(272): Introduce importlib.util.module_from_spec() as the
     preferred way to create a new module.

   - bpo-21552(273): Fixed possible integer overflow of too long string
     lengths in the tkinter module on 64-bit platforms.

   - bpo-14315(274): The zipfile module now ignores extra fields in the
     central directory that are too short to be parsed instead of
     letting a struct.unpack error bubble up as this “bad data” appears
     in many real world zip files in the wild and is ignored by other
     zip tools.

   - bpo-13742(275): Added “key” and “reverse” parameters to
     heapq.merge().  (First draft of patch contributed by Simon Sapin.)

   - bpo-21402(276): tkinter.ttk now works when default root window is
     not set.

   - bpo-3015(277): ‘_tkinter.create()’ now creates ‘tkapp’ object with
     ‘wantobjects=1’ by default.

   - bpo-10203(278): sqlite3.Row now truly supports sequence protocol.
     In particular it supports reverse() and negative indices.  Original
     patch by Claudiu Popa.

   - bpo-18807(279): If copying (no symlinks) specified for a venv, then
     the python interpreter aliases (python, python3) are now created by
     copying rather than symlinking.

   - bpo-20197(280): Added support for the WebP image type in the imghdr
     module.  Patch by Fabrice Aneche and Claudiu Popa.

   - bpo-21513(281): Speedup some properties of IP addresses
     (IPv4Address, IPv6Address) such as .is_private or .is_multicast.

   - bpo-21137(282): Improve the repr for threading.Lock() and its
     variants by showing the “locked” or “unlocked” status.  Patch by
     Berker Peksag.

   - bpo-21538(283): The plistlib module now supports loading of binary
     plist files when reference or offset size is not a power of two.

   - bpo-21455(284): Add a default backlog to socket.listen().

   - bpo-21525(285): Most Tkinter methods which accepted tuples now
     accept lists too.

   - bpo-22166(286): With the assistance of a new internal
     _codecs._forget_codec helping function, test_codecs now clears the
     encoding caches to avoid the appearance of a reference leak

   - bpo-22236(287): Tkinter tests now don’t reuse default root window.
     New root window is created for every test class.

   - bpo-10744(288): Fix PEP 3118(289) format strings on ctypes objects
     with a nontrivial shape.

   - bpo-20826(290): Optimize ipaddress.collapse_addresses().

   - bpo-21487(291): Optimize ipaddress.summarize_address_range() and
     ipaddress.{IPv4Network,IPv6Network}.subnets().

   - bpo-21486(292): Optimize parsing of netmasks in
     ipaddress.IPv4Network and ipaddress.IPv6Network.

   - bpo-13916(293): Disallowed the surrogatepass error handler for non
     UTF-* encodings.

   - bpo-20998(294): Fixed re.fullmatch() of repeated single character
     pattern with ignore case.  Original patch by Matthew Barnett.

   - bpo-21075(295): fileinput.FileInput now reads bytes from standard
     stream if binary mode is specified.  Patch by Sam Kimbrel.

   - bpo-19775(296): Add a samefile() method to pathlib Path objects.
     Initial patch by Vajrasky Kok.

   - bpo-21226(297): Set up modules properly in
     PyImport_ExecCodeModuleObject (and friends).

   - bpo-21398(298): Fix a unicode error in the pydoc pager when the
     documentation contains characters not encodable to the stdout
     encoding.

   - bpo-16531(299): ipaddress.IPv4Network and ipaddress.IPv6Network now
     accept an (address, netmask) tuple argument, so as to easily
     construct network objects from existing addresses.

   - bpo-21156(300): importlib.abc.InspectLoader.source_to_code() is now
     a staticmethod.

   - bpo-21424(301): Simplified and optimized heaqp.nlargest() and
     nmsmallest() to make fewer tuple comparisons.

   - bpo-21396(302): Fix TextIOWrapper(…, write_through=True) to not
     force a flush() on the underlying binary stream.  Patch by akira.

   - bpo-18314(303): Unlink now removes junctions on Windows.  Patch by
     Kim Gräsman

   - bpo-21088(304): Bugfix for curses.window.addch() regression in
     3.4.0.  In porting to Argument Clinic, the first two arguments were
     reversed.

   - bpo-21407(305): _decimal: The module now supports function
     signatures.

   - bpo-10650(306): Remove the non-standard ‘watchexp’ parameter from
     the Decimal.quantize() method in the Python version.  It had never
     been present in the C version.

   - bpo-21469(307): Reduced the risk of false positives in robotparser
     by checking to make sure that robots.txt has been read or does not
     exist prior to returning True in can_fetch().

   - bpo-19414(308): Have the OrderedDict mark deleted links as
     unusable.  This gives an early failure if the link is deleted
     during iteration.

   - bpo-21421(309): Add __slots__ to the MappingViews ABC. Patch by
     Josh Rosenberg.

   - bpo-21101(310): Eliminate double hashing in the C speed-up code for
     collections.Counter().

   - bpo-21321(311): itertools.islice() now releases the reference to
     the source iterator when the slice is exhausted.  Patch by Anton
     Afanasyev.

   - bpo-21057(312): TextIOWrapper now allows the underlying binary
     stream’s read() or read1() method to return an arbitrary bytes-like
     object (such as a memoryview).  Patch by Nikolaus Rath.

   - bpo-20951(313): SSLSocket.send() now raises either SSLWantReadError
     or SSLWantWriteError on a non-blocking socket if the operation
     would block.  Previously, it would return 0.  Patch by Nikolaus
     Rath.

   - bpo-13248(314): removed previously deprecated asyncore.dispatcher
     __getattr__ cheap inheritance hack.

   - bpo-9815(315): assertRaises now tries to clear references to local
     variables in the exception’s traceback.

   - bpo-19940(316): ssl.cert_time_to_seconds() now interprets the given
     time string in the UTC timezone (as specified in RFC 5280), not the
     local timezone.

   - bpo-13204(317): Calling sys.flags.__new__ would crash the
     interpreter, now it raises a TypeError.

   - bpo-19385(318): Make operations on a closed dbm.dumb database
     always raise the same exception.

   - bpo-21207(319): Detect when the os.urandom cached fd has been
     closed or replaced, and open it anew.

   - bpo-21291(320): subprocess’s Popen.wait() is now thread safe so
     that multiple threads may be calling wait() or poll() on a Popen
     instance at the same time without losing the Popen.returncode
     value.

   - bpo-21127(321): Path objects can now be instantiated from str
     subclass instances (such as ‘numpy.str_’).

   - bpo-15002(322): urllib.response object to use _TemporaryFileWrapper
     (and _TemporaryFileCloser) facility.  Provides a better way to
     handle file descriptor close.  Patch contributed by Christian
     Theune.

   - bpo-12220(323): mindom now raises a custom ValueError indicating it
     doesn’t support spaces in URIs instead of letting a ‘split’
     ValueError bubble up.

   - bpo-21068(324): The ssl.PROTOCOL* constants are now enum members.

   - bpo-21276(325): posixmodule: Don’t define USE_XATTRS on KFreeBSD
     and the Hurd.

   - bpo-21262(326): New method assert_not_called for Mock.  It raises
     AssertionError if the mock has been called.

   - bpo-21238(327): New keyword argument ‘unsafe’ to Mock.  It raises
     ‘AttributeError’ incase of an attribute startswith assert or
     assret.

   - bpo-20896(328): ssl.get_server_certificate() now uses
     PROTOCOL_SSLv23, not PROTOCOL_SSLv3, for maximum compatibility.

   - bpo-21239(329): patch.stopall() didn’t work deterministically when
     the same name was patched more than once.

   - bpo-21203(330): Updated fileConfig and dictConfig to remove
     inconsistencies.  Thanks to Jure Koren for the patch.

   - bpo-21222(331): Passing name keyword argument to
     mock.create_autospec now works.

   - bpo-21197(332): Add lib64 -> lib symlink in venvs on 64-bit non-OS
     X POSIX.

   - bpo-17498(333): Some SMTP servers disconnect after certain errors,
     violating strict RFC conformance.  Instead of losing the error code
     when we issue the subsequent RSET, smtplib now returns the error
     code and defers raising the SMTPServerDisconnected error until the
     next command is issued.

   - bpo-17826(334): setting an iterable side_effect on a mock function
     created by create_autospec now works.  Patch by Kushal Das.

   - bpo-7776(335): Fix ‘Host:’ header and reconnection when using
     http.client.HTTPConnection.set_tunnel().  Patch by Nikolaus Rath.

   - bpo-20968(336): unittest.mock.MagicMock now supports division.
     Patch by Johannes Baiter.

   - bpo-21529(337): Fix arbitrary memory access in
     JSONDecoder.raw_decode with a negative second parameter.  Bug
     reported by Guido Vranken.  (See also: CVE 2014-4616(338))

   - bpo-21169(339): getpass now handles non-ascii characters that the
     input stream encoding cannot encode by re-encoding using the
     replace error handler.

   - bpo-21171(340): Fixed undocumented filter API of the rot13 codec.
     Patch by Berker Peksag.

   - bpo-20539(341): Improved math.factorial error message for large
     positive inputs and changed exception type (OverflowError ->
     ValueError) for large negative inputs.

   - bpo-21172(342): isinstance check relaxed from dict to
     collections.Mapping.

   - bpo-21155(343): asyncio.EventLoop.create_unix_server() now raises a
     ValueError if path and sock are specified at the same time.

   - bpo-21136(344): Avoid unnecessary normalization of Fractions
     resulting from power and other operations.  Patch by Raymond
     Hettinger.

   - bpo-17621(345): Introduce importlib.util.LazyLoader.

   - bpo-21076(346): signal module constants were turned into enums.
     Patch by Giampaolo Rodola’.

   - bpo-20636(347): Improved the repr of Tkinter widgets.

   - bpo-19505(348): The items, keys, and values views of OrderedDict
     now support reverse iteration using reversed().

   - bpo-21149(349): Improved thread-safety in logging cleanup during
     interpreter shutdown.  Thanks to Devin Jeanpierre for the patch.

   - bpo-21058(350): Fix a leak of file descriptor in *note
     tempfile.NamedTemporaryFile(): 4c9, close the file descriptor if
     *note io.open(): 520. fails

   - bpo-21200(351): Return None from pkgutil.get_loader() when __spec__
     is missing.

   - bpo-21013(352): Enhance ssl.create_default_context() when used for
     server side sockets to provide better security by default.

   - bpo-20145(353): ‘assertRaisesRegex’ and ‘assertWarnsRegex’ now
     raise a ‘TypeError’ if the second argument is not a string or
     compiled regex.

   - bpo-20633(354): Replace relative import by absolute import.

   - bpo-20980(355): Stop wrapping exception when using ThreadPool.

   - bpo-21082(356): In os.makedirs, do not set the process-wide umask.
     Note this changes behavior of makedirs when exist_ok=True.

   - bpo-20990(357): Fix issues found by pyflakes for multiprocessing.

   - bpo-21015(358): SSL contexts will now automatically select an
     elliptic curve for ECDH key exchange on OpenSSL 1.0.2 and later,
     and otherwise default to “prime256v1”.

   - bpo-21000(359): Improve the command-line interface of json.tool.

   - bpo-20995(360): Enhance default ciphers used by the ssl module to
     enable better security and prioritize perfect forward secrecy.

   - bpo-20884(361): Don’t assume that __file__ is defined on
     importlib.__init__.

   - bpo-21499(362): Ignore __builtins__ in several
     test_importlib.test_api tests.

   - bpo-20627(363): xmlrpc.client.ServerProxy is now a context manager.

   - bpo-19165(364): The formatter module now raises DeprecationWarning
     instead of PendingDeprecationWarning.

   - bpo-13936(365): Remove the ability of datetime.time instances to be
     considered false in boolean contexts.

   - bpo-18931(366): selectors module now supports /dev/poll on Solaris.
     Patch by Giampaolo Rodola’.

   - bpo-19977(367): When the ‘LC_TYPE’ locale is the POSIX locale (‘C’
     locale), *note sys.stdin: 540. and *note sys.stdout: aec. are now
     using the ‘surrogateescape’ error handler, instead of the ‘strict’
     error handler.

   - bpo-20574(368): Implement incremental decoder for cp65001 code
     (Windows code page 65001, Microsoft UTF-8).

   - bpo-20879(369): Delay the initialization of encoding and decoding
     tables for base32, ascii85 and base85 codecs in the base64 module,
     and delay the initialization of the unquote_to_bytes() table of the
     urllib.parse module, to not waste memory if these modules are not
     used.

   - bpo-19157(370): Include the broadcast address in the usuable hosts
     for IPv6 in ipaddress.

   - bpo-11599(371): When an external command (e.g.  compiler) fails,
     distutils now prints out the whole command line (instead of just
     the command name) if the environment variable DISTUTILS_DEBUG is
     set.

   - bpo-4931(372): distutils should not produce unhelpful “error: None”
     messages anymore.  distutils.util.grok_environment_error is kept
     but doc-deprecated.

   - bpo-20875(373): Prevent possible gzip “‘read’ is not defined”
     NameError.  Patch by Claudiu Popa.

   - bpo-11558(374): ‘email.message.Message.attach’ now returns a more
     useful error message if ‘attach’ is called on a message for which
     ‘is_multipart’ is False.

   - bpo-20283(375): RE pattern methods now accept the string keyword
     parameters as documented.  The pattern and source keyword
     parameters are left as deprecated aliases.

   - bpo-20778(376): Fix modulefinder to work with bytecode-only
     modules.

   - bpo-20791(377): copy.copy() now doesn’t make a copy when the input
     is a bytes object.  Initial patch by Peter Otten.

   - bpo-19748(378): On AIX, time.mktime() now raises an OverflowError
     for year outsize range [1902; 2037].

   - bpo-19573(379): inspect.signature: Use enum for parameter kind
     constants.

   - bpo-20726(380): inspect.signature: Make Signature and Parameter
     picklable.

   - bpo-17373(381): Add inspect.Signature.from_callable method.

   - bpo-20378(382): Improve repr of inspect.Signature and
     inspect.Parameter.

   - bpo-20816(383): Fix inspect.getcallargs() to raise correct
     TypeError for missing keyword-only arguments.  Patch by Jeremiah
     Lowin.

   - bpo-20817(384): Fix inspect.getcallargs() to fail correctly if more
     than 3 arguments are missing.  Patch by Jeremiah Lowin.

   - bpo-6676(385): Ensure a meaningful exception is raised when
     attempting to parse more than one XML document per pyexpat
     xmlparser instance.  (Original patches by Hirokazu Yamamoto and
     Amaury Forgeot d’Arc, with suggested wording by David Gutteridge)

   - bpo-21117(386): Fix inspect.signature to better support
     functools.partial.  Due to the specifics of functools.partial
     implementation, positional-or-keyword arguments passed as keyword
     arguments become keyword-only.

   - bpo-20334(387): inspect.Signature and inspect.Parameter are now
     hashable.  Thanks to Antony Lee for bug reports and suggestions.

   - bpo-15916(388): doctest.DocTestSuite returns an empty
     unittest.TestSuite instead of raising ValueError if it finds no
     tests

   - bpo-21209(389): Fix asyncio.tasks.CoroWrapper to workaround a bug
     in yield-from implementation in CPythons prior to 3.4.1.

   - asyncio: Add gi_{frame,running,code} properties to CoroWrapper
     (upstream bpo-163(390)).

   - bpo-21311(391): Avoid exception in _osx_support with non-standard
     compiler configurations.  Patch by John Szakmeister.

   - bpo-11571(392): Ensure that the turtle window becomes the topmost
     window when launched on OS X.

   - bpo-21801(393): Validate that __signature__ is None or an instance
     of Signature.

   - bpo-21923(394): Prevent AttributeError in
     distutils.sysconfig.customize_compiler due to possible
     uninitialized _config_vars.

   - bpo-21323(395): Fix http.server to again handle scripts in CGI
     subdirectories, broken by the fix for security bpo-19435(396).
     Patch by Zach Byrne.

   - bpo-22733(397): Fix ffi_prep_args not zero-extending argument
     values correctly on 64-bit Windows.

   - bpo-23302(398): Default to TCP_NODELAY=1 upon establishing an
     HTTPConnection.  Removed use of hard-coded MSS as it’s an
     optimization that’s no longer needed with Nagle disabled.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23399

   (2) https://bugs.python.org/issue?@action=redirect&bpo=20289

   (3) https://bugs.python.org/issue?@action=redirect&bpo=13128

   (4) https://bugs.python.org/issue?@action=redirect&bpo=15381

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22818

   (6) https://bugs.python.org/issue?@action=redirect&bpo=23099

   (7) https://bugs.python.org/issue?@action=redirect&bpo=23326

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21408

   (9) https://bugs.python.org/issue?@action=redirect&bpo=23363

   (10) https://bugs.python.org/issue?@action=redirect&bpo=23364

   (11) https://bugs.python.org/issue?@action=redirect&bpo=23366

   (12) https://bugs.python.org/issue?@action=redirect&bpo=23369

   (13) https://bugs.python.org/issue?@action=redirect&bpo=23353

   (14) https://bugs.python.org/issue?@action=redirect&bpo=14099

   (15) https://bugs.python.org/issue?@action=redirect&bpo=14099

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19361

   (17) https://bugs.python.org/issue?@action=redirect&bpo=18518

   (18) https://bugs.python.org/issue?@action=redirect&bpo=23094

   (19) https://bugs.python.org/issue?@action=redirect&bpo=23268

   (20) https://bugs.python.org/issue?@action=redirect&bpo=21408

   (21) https://bugs.python.org/issue?@action=redirect&bpo=19996

   (22) https://bugs.python.org/issue?@action=redirect&bpo=20188

   (23) https://bugs.python.org/issue?@action=redirect&bpo=23133

   (24) https://bugs.python.org/issue?@action=redirect&bpo=23248

   (25) https://bugs.python.org/issue?@action=redirect&bpo=23266

   (26) https://bugs.python.org/issue?@action=redirect&bpo=23098

   (27) https://bugs.python.org/issue?@action=redirect&bpo=21817

   (28) https://bugs.python.org/issue?@action=redirect&bpo=15955

   (29) https://bugs.python.org/issue?@action=redirect&bpo=23250

   (30) https://bugs.python.org/issue?@action=redirect&bpo=23063

   (31) https://bugs.python.org/issue?@action=redirect&bpo=23209

   (32) https://bugs.python.org/issue?@action=redirect&bpo=23225

   (33) https://bugs.python.org/issue?@action=redirect&bpo=17911

   (34) https://bugs.python.org/issue?@action=redirect&bpo=17911

   (35) https://bugs.python.org/issue?@action=redirect&bpo=19777

   (36) https://bugs.python.org/issue?@action=redirect&bpo=23206

   (37) https://bugs.python.org/issue?@action=redirect&bpo=23185

   (38) https://bugs.python.org/issue?@action=redirect&bpo=23186

   (39) https://bugs.python.org/issue?@action=redirect&bpo=23143

   (40) https://bugs.python.org/issue?@action=redirect&bpo=23132

   (41) https://bugs.python.org/issue?@action=redirect&bpo=19776

   (42) https://bugs.python.org/issue?@action=redirect&bpo=23112

   (43) https://bugs.python.org/issue?@action=redirect&bpo=21793

   (44) https://bugs.python.org/issue?@action=redirect&bpo=23093

   (45) https://bugs.python.org/issue?@action=redirect&bpo=23111

   (46) https://bugs.python.org/issue?@action=redirect&bpo=22585

   (47) https://bugs.python.org/issue?@action=redirect&bpo=19104

   (48) https://bugs.python.org/issue?@action=redirect&bpo=23071

   (49) https://bugs.python.org/issue?@action=redirect&bpo=22783

   (50) https://bugs.python.org/issue?@action=redirect&bpo=15513

   (51) https://bugs.python.org/issue?@action=redirect&bpo=19858

   (52) https://bugs.python.org/issue?@action=redirect&bpo=22095

   (53) https://bugs.python.org/issue?@action=redirect&bpo=23016

   (54) https://bugs.python.org/issue?@action=redirect&bpo=21775

   (55) https://bugs.python.org/issue?@action=redirect&bpo=1218234

   (56) https://bugs.python.org/issue?@action=redirect&bpo=21740

   (57) https://bugs.python.org/issue?@action=redirect&bpo=23009

   (58) https://bugs.python.org/issue?@action=redirect&bpo=22959

   (59) https://bugs.python.org/issue?@action=redirect&bpo=22696

   (60) https://bugs.python.org/issue?@action=redirect&bpo=16043

   (61) https://www.cve.org/CVERecord?id=CVE-2013-1753

   (62) https://bugs.python.org/issue?@action=redirect&bpo=14099

   (63) https://bugs.python.org/issue?@action=redirect&bpo=22966

   (64) https://bugs.python.org/issue?@action=redirect&bpo=21971

   (65) https://bugs.python.org/issue?@action=redirect&bpo=21032

   (66) https://bugs.python.org/issue?@action=redirect&bpo=22407

   (67) https://bugs.python.org/issue?@action=redirect&bpo=22902

   (68) https://bugs.python.org/issue?@action=redirect&bpo=22960

   (69) https://bugs.python.org/issue?@action=redirect&bpo=22389

   (70) https://bugs.python.org/issue?@action=redirect&bpo=21356

   (71) https://bugs.python.org/issue?@action=redirect&bpo=22915

   (72) https://bugs.python.org/issue?@action=redirect&bpo=22609

   (73) https://bugs.python.org/issue?@action=redirect&bpo=22940

   (74) https://bugs.python.org/issue?@action=redirect&bpo=19676

   (75) https://bugs.python.org/issue?@action=redirect&bpo=22788

   (76) https://bugs.python.org/issue?@action=redirect&bpo=22921

   (77) https://bugs.python.org/issue?@action=redirect&bpo=22894

   (78) https://bugs.python.org/issue?@action=redirect&bpo=22796

   (79) https://bugs.python.org/issue?@action=redirect&bpo=22370

   (80) https://bugs.python.org/issue?@action=redirect&bpo=22841

   (81) https://bugs.python.org/issue?@action=redirect&bpo=19494

   (82) https://bugs.python.org/issue?@action=redirect&bpo=22578

   (83) https://bugs.python.org/issue?@action=redirect&bpo=22849

   (84) https://bugs.python.org/issue?@action=redirect&bpo=12728

   (85) https://bugs.python.org/issue?@action=redirect&bpo=22821

   (86) https://bugs.python.org/issue?@action=redirect&bpo=21650

   (87) https://bugs.python.org/issue?@action=redirect&bpo=22824

   (88) https://bugs.python.org/issue?@action=redirect&bpo=22824

   (89) https://bugs.python.org/issue?@action=redirect&bpo=22406

   (90) https://bugs.python.org/issue?@action=redirect&bpo=17293

   (91) https://bugs.python.org/issue?@action=redirect&bpo=22769

   (92) https://bugs.python.org/issue?@action=redirect&bpo=22417

   (93) https://bugs.python.org/issue?@action=redirect&bpo=22775

   (94) https://bugs.python.org/issue?@action=redirect&bpo=22776

   (95) https://bugs.python.org/issue?@action=redirect&bpo=22665

   (96) https://bugs.python.org/issue?@action=redirect&bpo=6623

   (97) https://bugs.python.org/issue?@action=redirect&bpo=17381

   (98) https://bugs.python.org/issue?@action=redirect&bpo=22410

   (99) https://bugs.python.org/issue?@action=redirect&bpo=22759

   (100) https://bugs.python.org/issue?@action=redirect&bpo=8876

   (101) https://bugs.python.org/issue?@action=redirect&bpo=22217

   (102) https://bugs.python.org/issue?@action=redirect&bpo=22457

   (103) https://bugs.python.org/issue?@action=redirect&bpo=18216

   (104) https://bugs.python.org/issue?@action=redirect&bpo=13918

   (105) https://bugs.python.org/issue?@action=redirect&bpo=22676

   (106) https://bugs.python.org/issue?@action=redirect&bpo=18853

   (107) https://bugs.python.org/issue?@action=redirect&bpo=9351

   (108) https://bugs.python.org/issue?@action=redirect&bpo=7559

   (109) https://bugs.python.org/issue?@action=redirect&bpo=19746

   (110) https://bugs.python.org/issue?@action=redirect&bpo=21991

   (111) https://bugs.python.org/issue?@action=redirect&bpo=22638

   (112) https://bugs.python.org/issue?@action=redirect&bpo=22641

   (113) https://bugs.python.org/issue?@action=redirect&bpo=17401

   (114) https://bugs.python.org/issue?@action=redirect&bpo=21338

   (115) https://bugs.python.org/issue?@action=redirect&bpo=20152

   (116) https://bugs.python.org/issue?@action=redirect&bpo=18643

   (117) https://bugs.python.org/issue?@action=redirect&bpo=22435

   (118) https://bugs.python.org/issue?@action=redirect&bpo=13096

   (119) https://bugs.python.org/issue?@action=redirect&bpo=11694

   (120) https://bugs.python.org/issue?@action=redirect&bpo=19380

   (121) https://bugs.python.org/issue?@action=redirect&bpo=1519638

   (122) https://bugs.python.org/issue?@action=redirect&bpo=18615

   (123) https://bugs.python.org/issue?@action=redirect&bpo=22462

   (124) https://bugs.python.org/issue?@action=redirect&bpo=21965

   (125) https://bugs.python.org/issue?@action=redirect&bpo=21173

   (126) https://bugs.python.org/issue?@action=redirect&bpo=11866

   (127) https://bugs.python.org/issue?@action=redirect&bpo=21905

   (128) https://bugs.python.org/issue?@action=redirect&bpo=11271

   (129) https://bugs.python.org/issue?@action=redirect&bpo=21883

   (130) https://bugs.python.org/issue?@action=redirect&bpo=22219

   (131) https://bugs.python.org/issue?@action=redirect&bpo=22449

   (132) https://bugs.python.org/issue?@action=redirect&bpo=22508

   (133) https://bugs.python.org/issue?@action=redirect&bpo=20076

   (134) https://bugs.python.org/issue?@action=redirect&bpo=20079

   (135) https://bugs.python.org/issue?@action=redirect&bpo=20218

   (136) https://bugs.python.org/issue?@action=redirect&bpo=22396

   (137) https://bugs.python.org/issue?@action=redirect&bpo=22517

   (138) https://bugs.python.org/issue?@action=redirect&bpo=22437

   (139) https://bugs.python.org/issue?@action=redirect&bpo=17442

   (140) https://bugs.python.org/issue?@action=redirect&bpo=23392

   (141) https://bugs.python.org/issue?@action=redirect&bpo=10510

   (142) https://bugs.python.org/issue?@action=redirect&bpo=9850

   (143) https://bugs.python.org/issue?@action=redirect&bpo=5309

   (144) https://bugs.python.org/issue?@action=redirect&bpo=22448

   (145) https://bugs.python.org/issue?@action=redirect&bpo=22427

   (146) https://bugs.python.org/issue?@action=redirect&bpo=22362

   (147) https://bugs.python.org/issue?@action=redirect&bpo=20912

   (148) https://bugs.python.org/issue?@action=redirect&bpo=21866

   (149) https://bugs.python.org/issue?@action=redirect&bpo=22278

   (150) https://bugs.python.org/issue?@action=redirect&bpo=22415

   (151) https://bugs.python.org/issue?@action=redirect&bpo=22423

   (152) https://bugs.python.org/issue?@action=redirect&bpo=21332

   (153) https://bugs.python.org/issue?@action=redirect&bpo=21091

   (154) https://bugs.python.org/issue?@action=redirect&bpo=21079

   (155) https://bugs.python.org/issue?@action=redirect&bpo=22247

   (156) https://bugs.python.org/issue?@action=redirect&bpo=22366

   (157) https://bugs.python.org/issue?@action=redirect&bpo=4180

   (158) https://bugs.python.org/issue?@action=redirect&bpo=22419

   (159) https://bugs.python.org/issue?@action=redirect&bpo=20537

   (160) https://bugs.python.org/issue?@action=redirect&bpo=22384

   (161) https://bugs.python.org/issue?@action=redirect&bpo=22168

   (162) https://bugs.python.org/issue?@action=redirect&bpo=21147

   (163) https://bugs.python.org/issue?@action=redirect&bpo=13968

   (164) https://bugs.python.org/issue?@action=redirect&bpo=21951

   (165) https://bugs.python.org/issue?@action=redirect&bpo=21951

   (166) https://bugs.python.org/issue?@action=redirect&bpo=22338

   (167) https://bugs.python.org/issue?@action=redirect&bpo=12410

   (168) https://bugs.python.org/issue?@action=redirect&bpo=21270

   (169) https://bugs.python.org/issue?@action=redirect&bpo=16662

   (170) https://bugs.python.org/issue?@action=redirect&bpo=22226

   (171) https://bugs.python.org/issue?@action=redirect&bpo=19524

   (172) https://bugs.python.org/issue?@action=redirect&bpo=20421

   (173) https://bugs.python.org/issue?@action=redirect&bpo=19546

   (174) https://bugs.python.org/issue?@action=redirect&bpo=22051

   (175) https://bugs.python.org/issue?@action=redirect&bpo=21933

   (176) https://bugs.python.org/issue?@action=redirect&bpo=21597

   (177) https://bugs.python.org/issue?@action=redirect&bpo=18132

   (178) https://bugs.python.org/issue?@action=redirect&bpo=22043

   (179) https://bugs.python.org/issue?@action=redirect&bpo=21527

   (180) https://bugs.python.org/issue?@action=redirect&bpo=22216

   (181) https://bugs.python.org/issue?@action=redirect&bpo=22098

   (182) https://bugs.python.org/issue?@action=redirect&bpo=22185

   (183) https://bugs.python.org/issue?@action=redirect&bpo=22287

   (184) https://bugs.python.org/issue?@action=redirect&bpo=22182

   (185) https://bugs.python.org/issue?@action=redirect&bpo=22042

   (186) https://bugs.python.org/issue?@action=redirect&bpo=16808

   (187) https://bugs.python.org/issue?@action=redirect&bpo=22236

   (188) https://bugs.python.org/issue?@action=redirect&bpo=2527

   (189) https://bugs.python.org/issue?@action=redirect&bpo=22118

   (190) https://bugs.python.org/issue?@action=redirect&bpo=21549

   (191) https://bugs.python.org/issue?@action=redirect&bpo=19628

   (192) https://bugs.python.org/issue?@action=redirect&bpo=15696

   (193) https://bugs.python.org/issue?@action=redirect&bpo=22068

   (194) https://bugs.python.org/issue?@action=redirect&bpo=22165

   (195) https://bugs.python.org/issue?@action=redirect&bpo=15381

   (196) https://bugs.python.org/issue?@action=redirect&bpo=8797

   (197) https://bugs.python.org/issue?@action=redirect&bpo=20729

   (198) https://bugs.python.org/issue?@action=redirect&bpo=21448

   (199) https://bugs.python.org/issue?@action=redirect&bpo=22184

   (200) https://bugs.python.org/issue?@action=redirect&bpo=17923

   (201) https://bugs.python.org/issue?@action=redirect&bpo=21725

   (202) https://bugs.python.org/issue?@action=redirect&bpo=22176

   (203) https://bugs.python.org/issue?@action=redirect&bpo=5411

   (204) https://bugs.python.org/issue?@action=redirect&bpo=21121

   (205) https://bugs.python.org/issue?@action=redirect&bpo=21975

   (206) https://bugs.python.org/issue?@action=redirect&bpo=20170

   (207) https://bugs.python.org/issue?@action=redirect&bpo=21539

   (208) https://bugs.python.org/issue?@action=redirect&bpo=22127

   (209) https://bugs.python.org/issue?@action=redirect&bpo=21047

   (210) https://bugs.python.org/issue?@action=redirect&bpo=15114

   (211) https://bugs.python.org/issue?@action=redirect&bpo=22085

   (212) https://bugs.python.org/issue?@action=redirect&bpo=21580

   (213) https://bugs.python.org/issue?@action=redirect&bpo=22003

   (214) https://bugs.python.org/issue?@action=redirect&bpo=22018

   (215) https://bugs.python.org/issue?@action=redirect&bpo=22054

   (216) https://bugs.python.org/issue?@action=redirect&bpo=17172

   (217) https://bugs.python.org/issue?@action=redirect&bpo=21704

   (218) https://bugs.python.org/issue?@action=redirect&bpo=20173

   (219) https://bugs.python.org/issue?@action=redirect&bpo=22033

   (220) https://bugs.python.org/issue?@action=redirect&bpo=21947

   (221) https://bugs.python.org/issue?@action=redirect&bpo=16133

   (222) https://bugs.python.org/issue?@action=redirect&bpo=22044

   (223) https://bugs.python.org/issue?@action=redirect&bpo=19884

   (224) https://bugs.python.org/issue?@action=redirect&bpo=4350

   (225) https://bugs.python.org/issue?@action=redirect&bpo=6167

   (226) https://bugs.python.org/issue?@action=redirect&bpo=15275

   (227) https://bugs.python.org/issue?@action=redirect&bpo=21888

   (228) https://bugs.python.org/issue?@action=redirect&bpo=22032

   (229) https://bugs.python.org/issue?@action=redirect&bpo=22031

   (230) https://bugs.python.org/issue?@action=redirect&bpo=22018

   (231) https://bugs.python.org/issue?@action=redirect&bpo=21044

   (232) https://bugs.python.org/issue?@action=redirect&bpo=21966

   (233) https://bugs.python.org/issue?@action=redirect&bpo=19076

   (234) https://bugs.python.org/issue?@action=redirect&bpo=16382

   (235) https://bugs.python.org/issue?@action=redirect&bpo=21932

   (236) https://bugs.python.org/issue?@action=redirect&bpo=21942

   (237) https://bugs.python.org/issue?@action=redirect&bpo=11259

   (238) https://bugs.python.org/issue?@action=redirect&bpo=12523

   (239) https://bugs.python.org/issue?@action=redirect&bpo=21707

   (240) https://bugs.python.org/issue?@action=redirect&bpo=20639

   (241) https://bugs.python.org/issue?@action=redirect&bpo=21714

   (242) https://bugs.python.org/issue?@action=redirect&bpo=15014

   (243) https://bugs.python.org/issue?@action=redirect&bpo=21151

   (244) https://bugs.python.org/issue?@action=redirect&bpo=21090

   (245) https://bugs.python.org/issue?@action=redirect&bpo=5800

   (246) https://bugs.python.org/issue?@action=redirect&bpo=21781

   (247) https://bugs.python.org/issue?@action=redirect&bpo=21679

   (248) https://bugs.python.org/issue?@action=redirect&bpo=21863

   (249) https://bugs.python.org/issue?@action=redirect&bpo=11453

   (250) https://bugs.python.org/issue?@action=redirect&bpo=21858

   (251) https://bugs.python.org/issue?@action=redirect&bpo=21476

   (252) https://bugs.python.org/issue?@action=redirect&bpo=20295

   (253) https://bugs.python.org/issue?@action=redirect&bpo=21729

   (254) https://bugs.python.org/issue?@action=redirect&bpo=21491

   (255) https://bugs.python.org/issue?@action=redirect&bpo=21719

   (256) https://bugs.python.org/issue?@action=redirect&bpo=21832

   (257) https://bugs.python.org/issue?@action=redirect&bpo=21722

   (258) https://bugs.python.org/issue?@action=redirect&bpo=21723

   (259) https://bugs.python.org/issue?@action=redirect&bpo=21711

   (260) https://bugs.python.org/issue?@action=redirect&bpo=17552

   (261) https://bugs.python.org/issue?@action=redirect&bpo=18039

   (262) https://bugs.python.org/issue?@action=redirect&bpo=21326

   (263) https://bugs.python.org/issue?@action=redirect&bpo=21766

   (264) https://bugs.python.org/issue?@action=redirect&bpo=21310

   (265) https://bugs.python.org/issue?@action=redirect&bpo=21256

   (266) https://bugs.python.org/issue?@action=redirect&bpo=21677

   (267) https://bugs.python.org/issue?@action=redirect&bpo=11709

   (268) https://bugs.python.org/issue?@action=redirect&bpo=21515

   (269) https://bugs.python.org/issue?@action=redirect&bpo=13223

   (270) https://bugs.python.org/issue?@action=redirect&bpo=21463

   (271) https://bugs.python.org/issue?@action=redirect&bpo=21618

   (272) https://bugs.python.org/issue?@action=redirect&bpo=20383

   (273) https://bugs.python.org/issue?@action=redirect&bpo=21552

   (274) https://bugs.python.org/issue?@action=redirect&bpo=14315

   (275) https://bugs.python.org/issue?@action=redirect&bpo=13742

   (276) https://bugs.python.org/issue?@action=redirect&bpo=21402

   (277) https://bugs.python.org/issue?@action=redirect&bpo=3015

   (278) https://bugs.python.org/issue?@action=redirect&bpo=10203

   (279) https://bugs.python.org/issue?@action=redirect&bpo=18807

   (280) https://bugs.python.org/issue?@action=redirect&bpo=20197

   (281) https://bugs.python.org/issue?@action=redirect&bpo=21513

   (282) https://bugs.python.org/issue?@action=redirect&bpo=21137

   (283) https://bugs.python.org/issue?@action=redirect&bpo=21538

   (284) https://bugs.python.org/issue?@action=redirect&bpo=21455

   (285) https://bugs.python.org/issue?@action=redirect&bpo=21525

   (286) https://bugs.python.org/issue?@action=redirect&bpo=22166

   (287) https://bugs.python.org/issue?@action=redirect&bpo=22236

   (288) https://bugs.python.org/issue?@action=redirect&bpo=10744

   (289) https://peps.python.org/pep-3118/

   (290) https://bugs.python.org/issue?@action=redirect&bpo=20826

   (291) https://bugs.python.org/issue?@action=redirect&bpo=21487

   (292) https://bugs.python.org/issue?@action=redirect&bpo=21486

   (293) https://bugs.python.org/issue?@action=redirect&bpo=13916

   (294) https://bugs.python.org/issue?@action=redirect&bpo=20998

   (295) https://bugs.python.org/issue?@action=redirect&bpo=21075

   (296) https://bugs.python.org/issue?@action=redirect&bpo=19775

   (297) https://bugs.python.org/issue?@action=redirect&bpo=21226

   (298) https://bugs.python.org/issue?@action=redirect&bpo=21398

   (299) https://bugs.python.org/issue?@action=redirect&bpo=16531

   (300) https://bugs.python.org/issue?@action=redirect&bpo=21156

   (301) https://bugs.python.org/issue?@action=redirect&bpo=21424

   (302) https://bugs.python.org/issue?@action=redirect&bpo=21396

   (303) https://bugs.python.org/issue?@action=redirect&bpo=18314

   (304) https://bugs.python.org/issue?@action=redirect&bpo=21088

   (305) https://bugs.python.org/issue?@action=redirect&bpo=21407

   (306) https://bugs.python.org/issue?@action=redirect&bpo=10650

   (307) https://bugs.python.org/issue?@action=redirect&bpo=21469

   (308) https://bugs.python.org/issue?@action=redirect&bpo=19414

   (309) https://bugs.python.org/issue?@action=redirect&bpo=21421

   (310) https://bugs.python.org/issue?@action=redirect&bpo=21101

   (311) https://bugs.python.org/issue?@action=redirect&bpo=21321

   (312) https://bugs.python.org/issue?@action=redirect&bpo=21057

   (313) https://bugs.python.org/issue?@action=redirect&bpo=20951

   (314) https://bugs.python.org/issue?@action=redirect&bpo=13248

   (315) https://bugs.python.org/issue?@action=redirect&bpo=9815

   (316) https://bugs.python.org/issue?@action=redirect&bpo=19940

   (317) https://bugs.python.org/issue?@action=redirect&bpo=13204

   (318) https://bugs.python.org/issue?@action=redirect&bpo=19385

   (319) https://bugs.python.org/issue?@action=redirect&bpo=21207

   (320) https://bugs.python.org/issue?@action=redirect&bpo=21291

   (321) https://bugs.python.org/issue?@action=redirect&bpo=21127

   (322) https://bugs.python.org/issue?@action=redirect&bpo=15002

   (323) https://bugs.python.org/issue?@action=redirect&bpo=12220

   (324) https://bugs.python.org/issue?@action=redirect&bpo=21068

   (325) https://bugs.python.org/issue?@action=redirect&bpo=21276

   (326) https://bugs.python.org/issue?@action=redirect&bpo=21262

   (327) https://bugs.python.org/issue?@action=redirect&bpo=21238

   (328) https://bugs.python.org/issue?@action=redirect&bpo=20896

   (329) https://bugs.python.org/issue?@action=redirect&bpo=21239

   (330) https://bugs.python.org/issue?@action=redirect&bpo=21203

   (331) https://bugs.python.org/issue?@action=redirect&bpo=21222

   (332) https://bugs.python.org/issue?@action=redirect&bpo=21197

   (333) https://bugs.python.org/issue?@action=redirect&bpo=17498

   (334) https://bugs.python.org/issue?@action=redirect&bpo=17826

   (335) https://bugs.python.org/issue?@action=redirect&bpo=7776

   (336) https://bugs.python.org/issue?@action=redirect&bpo=20968

   (337) https://bugs.python.org/issue?@action=redirect&bpo=21529

   (338) https://www.cve.org/CVERecord?id=CVE-2014-4616

   (339) https://bugs.python.org/issue?@action=redirect&bpo=21169

   (340) https://bugs.python.org/issue?@action=redirect&bpo=21171

   (341) https://bugs.python.org/issue?@action=redirect&bpo=20539

   (342) https://bugs.python.org/issue?@action=redirect&bpo=21172

   (343) https://bugs.python.org/issue?@action=redirect&bpo=21155

   (344) https://bugs.python.org/issue?@action=redirect&bpo=21136

   (345) https://bugs.python.org/issue?@action=redirect&bpo=17621

   (346) https://bugs.python.org/issue?@action=redirect&bpo=21076

   (347) https://bugs.python.org/issue?@action=redirect&bpo=20636

   (348) https://bugs.python.org/issue?@action=redirect&bpo=19505

   (349) https://bugs.python.org/issue?@action=redirect&bpo=21149

   (350) https://bugs.python.org/issue?@action=redirect&bpo=21058

   (351) https://bugs.python.org/issue?@action=redirect&bpo=21200

   (352) https://bugs.python.org/issue?@action=redirect&bpo=21013

   (353) https://bugs.python.org/issue?@action=redirect&bpo=20145

   (354) https://bugs.python.org/issue?@action=redirect&bpo=20633

   (355) https://bugs.python.org/issue?@action=redirect&bpo=20980

   (356) https://bugs.python.org/issue?@action=redirect&bpo=21082

   (357) https://bugs.python.org/issue?@action=redirect&bpo=20990

   (358) https://bugs.python.org/issue?@action=redirect&bpo=21015

   (359) https://bugs.python.org/issue?@action=redirect&bpo=21000

   (360) https://bugs.python.org/issue?@action=redirect&bpo=20995

   (361) https://bugs.python.org/issue?@action=redirect&bpo=20884

   (362) https://bugs.python.org/issue?@action=redirect&bpo=21499

   (363) https://bugs.python.org/issue?@action=redirect&bpo=20627

   (364) https://bugs.python.org/issue?@action=redirect&bpo=19165

   (365) https://bugs.python.org/issue?@action=redirect&bpo=13936

   (366) https://bugs.python.org/issue?@action=redirect&bpo=18931

   (367) https://bugs.python.org/issue?@action=redirect&bpo=19977

   (368) https://bugs.python.org/issue?@action=redirect&bpo=20574

   (369) https://bugs.python.org/issue?@action=redirect&bpo=20879

   (370) https://bugs.python.org/issue?@action=redirect&bpo=19157

   (371) https://bugs.python.org/issue?@action=redirect&bpo=11599

   (372) https://bugs.python.org/issue?@action=redirect&bpo=4931

   (373) https://bugs.python.org/issue?@action=redirect&bpo=20875

   (374) https://bugs.python.org/issue?@action=redirect&bpo=11558

   (375) https://bugs.python.org/issue?@action=redirect&bpo=20283

   (376) https://bugs.python.org/issue?@action=redirect&bpo=20778

   (377) https://bugs.python.org/issue?@action=redirect&bpo=20791

   (378) https://bugs.python.org/issue?@action=redirect&bpo=19748

   (379) https://bugs.python.org/issue?@action=redirect&bpo=19573

   (380) https://bugs.python.org/issue?@action=redirect&bpo=20726

   (381) https://bugs.python.org/issue?@action=redirect&bpo=17373

   (382) https://bugs.python.org/issue?@action=redirect&bpo=20378

   (383) https://bugs.python.org/issue?@action=redirect&bpo=20816

   (384) https://bugs.python.org/issue?@action=redirect&bpo=20817

   (385) https://bugs.python.org/issue?@action=redirect&bpo=6676

   (386) https://bugs.python.org/issue?@action=redirect&bpo=21117

   (387) https://bugs.python.org/issue?@action=redirect&bpo=20334

   (388) https://bugs.python.org/issue?@action=redirect&bpo=15916

   (389) https://bugs.python.org/issue?@action=redirect&bpo=21209

   (390) https://bugs.python.org/issue?@action=redirect&bpo=163

   (391) https://bugs.python.org/issue?@action=redirect&bpo=21311

   (392) https://bugs.python.org/issue?@action=redirect&bpo=11571

   (393) https://bugs.python.org/issue?@action=redirect&bpo=21801

   (394) https://bugs.python.org/issue?@action=redirect&bpo=21923

   (395) https://bugs.python.org/issue?@action=redirect&bpo=21323

   (396) https://bugs.python.org/issue?@action=redirect&bpo=19435

   (397) https://bugs.python.org/issue?@action=redirect&bpo=22733

   (398) https://bugs.python.org/issue?@action=redirect&bpo=23302


File: python.info,  Node: IDLE<67>,  Next: Build<99>,  Prev: Library<183>,  Up: Python 3 5 0 alpha 1

1.23.121.3 IDLE
...............

   - bpo-20577(1): Configuration of the max line length for the
     FormatParagraph extension has been moved from the General tab of
     the Idle preferences dialog to the FormatParagraph tab of the
     Config Extensions dialog.  Patch by Tal Einat.

   - bpo-16893(2): Update Idle doc chapter to match current Idle and add
     new information.

   - bpo-3068(3): Add Idle extension configuration dialog to Options
     menu.  Changes are written to HOME/.idlerc/config-extensions.cfg.
     Original patch by Tal Einat.

   - bpo-16233(4): A module browser (File : Class Browser, Alt+C)
     requires an editor window with a filename.  When Class Browser is
     requested otherwise, from a shell, output window, or ‘Untitled’
     editor, Idle no longer displays an error box.  It now pops up an
     Open Module box (Alt+M). If a valid name is entered and a module is
     opened, a corresponding browser is also opened.

   - bpo-4832(5): Save As to type Python files automatically adds .py to
     the name you enter (even if your system does not display it).  Some
     systems automatically add .txt when type is Text files.

   - bpo-21986(6): Code objects are not normally pickled by the pickle
     module.  To match this, they are no longer pickled when running
     under Idle.

   - bpo-17390(7): Adjust Editor window title; remove ‘Python’, move
     version to end.

   - bpo-14105(8): Idle debugger breakpoints no longer disappear when
     inserting or deleting lines.

   - bpo-17172(9): Turtledemo can now be run from Idle.  Currently, the
     entry is on the Help menu, but it may move to Run.  Patch by
     Ramchandra Apt and Lita Cho.

   - bpo-21765(10): Add support for non-ascii identifiers to
     HyperParser.

   - bpo-21940(11): Add unittest for WidgetRedirector.  Initial patch by
     Saimadhav Heblikar.

   - bpo-18592(12): Add unittest for SearchDialogBase.  Patch by Phil
     Webster.

   - bpo-21694(13): Add unittest for ParenMatch.  Patch by Saimadhav
     Heblikar.

   - bpo-21686(14): add unittest for HyperParser.  Original patch by
     Saimadhav Heblikar.

   - bpo-12387(15): Add missing upper(lower)case versions of default
     Windows key bindings for Idle so Caps Lock does not disable them.
     Patch by Roger Serwy.

   - bpo-21695(16): Closing a Find-in-files output window while the
     search is still in progress no longer closes Idle.

   - bpo-18910(17): Add unittest for textView.  Patch by Phil Webster.

   - bpo-18292(18): Add unittest for AutoExpand.  Patch by Saihadhav
     Heblikar.

   - bpo-18409(19): Add unittest for AutoComplete.  Patch by Phil
     Webster.

   - bpo-21477(20): htest.py - Improve framework, complete set of tests.
     Patches by Saimadhav Heblikar

   - bpo-18104(21): Add idlelib/idle_test/htest.py with a few sample
     tests to begin consolidating and improving human-validated tests of
     Idle.  Change other files as needed to work with htest.  Running
     the module as __main__ runs all tests.

   - bpo-21139(22): Change default paragraph width to 72, the PEP 8(23)
     recommendation.

   - bpo-21284(24): Paragraph reformat test passes after user changes
     reformat width.

   - bpo-17654(25): Ensure IDLE menus are customized properly on OS X
     for non-framework builds and for all variants of Tk.

   - bpo-23180(26): Rename IDLE “Windows” menu item to “Window”.  Patch
     by Al Sweigart.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=20577

   (2) https://bugs.python.org/issue?@action=redirect&bpo=16893

   (3) https://bugs.python.org/issue?@action=redirect&bpo=3068

   (4) https://bugs.python.org/issue?@action=redirect&bpo=16233

   (5) https://bugs.python.org/issue?@action=redirect&bpo=4832

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21986

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17390

   (8) https://bugs.python.org/issue?@action=redirect&bpo=14105

   (9) https://bugs.python.org/issue?@action=redirect&bpo=17172

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21765

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21940

   (12) https://bugs.python.org/issue?@action=redirect&bpo=18592

   (13) https://bugs.python.org/issue?@action=redirect&bpo=21694

   (14) https://bugs.python.org/issue?@action=redirect&bpo=21686

   (15) https://bugs.python.org/issue?@action=redirect&bpo=12387

   (16) https://bugs.python.org/issue?@action=redirect&bpo=21695

   (17) https://bugs.python.org/issue?@action=redirect&bpo=18910

   (18) https://bugs.python.org/issue?@action=redirect&bpo=18292

   (19) https://bugs.python.org/issue?@action=redirect&bpo=18409

   (20) https://bugs.python.org/issue?@action=redirect&bpo=21477

   (21) https://bugs.python.org/issue?@action=redirect&bpo=18104

   (22) https://bugs.python.org/issue?@action=redirect&bpo=21139

   (23) https://peps.python.org/pep-0008/

   (24) https://bugs.python.org/issue?@action=redirect&bpo=21284

   (25) https://bugs.python.org/issue?@action=redirect&bpo=17654

   (26) https://bugs.python.org/issue?@action=redirect&bpo=23180


File: python.info,  Node: Build<99>,  Next: C API<78>,  Prev: IDLE<67>,  Up: Python 3 5 0 alpha 1

1.23.121.4 Build
................

   - bpo-15506(1): Use standard PKG_PROG_PKG_CONFIG autoconf macro in
     the configure script.

   - bpo-22935(2): Allow the ssl module to be compiled if openssl
     doesn’t support SSL 3.

   - bpo-22592(3): Drop support of the Borland C compiler to build
     Python.  The distutils module still supports it to build
     extensions.

   - bpo-22591(4): Drop support of MS-DOS, especially of the DJGPP
     compiler (MS-DOS port of GCC).

   - bpo-16537(5): Check whether self.extensions is empty in setup.py.
     Patch by Jonathan Hosmer.

   - bpo-22359(6): Remove incorrect uses of recursive make.  Patch by
     Jonas Wagner.

   - bpo-21958(7): Define HAVE_ROUND when building with Visual Studio
     2013 and above.  Patch by Zachary Turner.

   - bpo-18093(8): the programs that embed the CPython runtime are now
     in a separate “Programs” directory, rather than being kept in the
     Modules directory.

   - bpo-15759(9): “make suspicious”, “make linkcheck” and “make
     doctest” in Doc/ now display special message when and only when
     there are failures.

   - bpo-21141(10): The Windows build process no longer attempts to find
     Perl, instead relying on OpenSSL source being configured and ready
     to build.  The ‘PCbuild\build_ssl.py’ script has been re-written
     and re-named to ‘PCbuild\prepare_ssl.py’, and takes care of
     configuring OpenSSL source for both 32 and 64 bit platforms.
     OpenSSL sources obtained from svn.python.org will always be
     pre-configured and ready to build.

   - bpo-21037(11): Add a build option to enable AddressSanitizer
     support.

   - bpo-19962(12): The Windows build process now creates “python.bat”
     in the root of the source tree, which passes all arguments through
     to the most recently built interpreter.

   - bpo-21285(13): Refactor and fix curses configure check to always
     search in a ncursesw directory.

   - bpo-15234(14): For BerkeleyDB and Sqlite, only add the found
     library and include directories if they aren’t already being
     searched.  This avoids an explicit runtime library dependency.

   - bpo-17861(15): Tools/scripts/generate_opcode_h.py automatically
     regenerates Include/opcode.h from Lib/opcode.py if the latter gets
     any change.

   - bpo-20644(16): OS X installer build support for documentation build
     changes in 3.4.1: assume externally supplied sphinx-build is
     available in /usr/bin.

   - bpo-20022(17): Eliminate use of deprecated bundlebuilder in OS X
     builds.

   - bpo-15968(18): Incorporated Tcl, Tk, and Tix builds into the
     Windows build solution.

   - bpo-17095(19): Fix Modules/Setup 'shared' support.

   - bpo-21811(20): Anticipated fixes to support OS X versions > 10.9.

   - bpo-21166(21): Prevent possible segfaults and other random failures
     of python –generate-posix-vars in pybuilddir.txt build target.

   - bpo-18096(22): Fix library order returned by python-config.

   - bpo-17219(23): Add library build dir for Python extension
     cross-builds.

   - bpo-22919(24): Windows build updated to support VC 14.0 (Visual
     Studio 2015), which will be used for the official release.

   - bpo-21236(25): Build _msi.pyd with cabinet.lib instead of fci.lib

   - bpo-17128(26): Use private version of OpenSSL for OS X 10.5+
     installer.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=15506

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22935

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22592

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22591

   (5) https://bugs.python.org/issue?@action=redirect&bpo=16537

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22359

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21958

   (8) https://bugs.python.org/issue?@action=redirect&bpo=18093

   (9) https://bugs.python.org/issue?@action=redirect&bpo=15759

   (10) https://bugs.python.org/issue?@action=redirect&bpo=21141

   (11) https://bugs.python.org/issue?@action=redirect&bpo=21037

   (12) https://bugs.python.org/issue?@action=redirect&bpo=19962

   (13) https://bugs.python.org/issue?@action=redirect&bpo=21285

   (14) https://bugs.python.org/issue?@action=redirect&bpo=15234

   (15) https://bugs.python.org/issue?@action=redirect&bpo=17861

   (16) https://bugs.python.org/issue?@action=redirect&bpo=20644

   (17) https://bugs.python.org/issue?@action=redirect&bpo=20022

   (18) https://bugs.python.org/issue?@action=redirect&bpo=15968

   (19) https://bugs.python.org/issue?@action=redirect&bpo=17095

   (20) https://bugs.python.org/issue?@action=redirect&bpo=21811

   (21) https://bugs.python.org/issue?@action=redirect&bpo=21166

   (22) https://bugs.python.org/issue?@action=redirect&bpo=18096

   (23) https://bugs.python.org/issue?@action=redirect&bpo=17219

   (24) https://bugs.python.org/issue?@action=redirect&bpo=22919

   (25) https://bugs.python.org/issue?@action=redirect&bpo=21236

   (26) https://bugs.python.org/issue?@action=redirect&bpo=17128


File: python.info,  Node: C API<78>,  Next: Documentation<83>,  Prev: Build<99>,  Up: Python 3 5 0 alpha 1

1.23.121.5 C API
................

   - bpo-14203(1): Remove obsolete support for view==NULL in
     PyBuffer_FillInfo(), bytearray_getbuffer(), bytesiobuf_getbuffer()
     and array_buffer_getbuf().  All functions now raise BufferError in
     that case.

   - bpo-22445(2): PyBuffer_IsContiguous() now implements precise
     contiguity tests, compatible with NumPy’s
     NPY_RELAXED_STRIDES_CHECKING compilation flag.  Previously the
     function reported false negatives for corner cases.

   - bpo-22079(3): PyType_Ready() now checks that statically allocated
     type has no dynamically allocated bases.

   - bpo-22453(4): Removed non-documented macro PyObject_REPR().

   - bpo-18395(5): Rename ‘_Py_char2wchar()’ to *note Py_DecodeLocale():
     be6, rename ‘_Py_wchar2char()’ to *note Py_EncodeLocale(): be7, and
     document these functions.

   - bpo-21233(6): Add new C functions: PyMem_RawCalloc(),
     PyMem_Calloc(), PyObject_Calloc(), _PyObject_GC_Calloc().
     bytes(int) is now using ‘calloc()’ instead of ‘malloc()’ for large
     objects which is faster and use less memory.

   - bpo-20942(7): PyImport_ImportFrozenModuleObject() no longer sets
     __file__ to match what importlib does; this affects
     _frozen_importlib as well as any module loaded using
     imp.init_frozen().

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=14203

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22445

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22079

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22453

   (5) https://bugs.python.org/issue?@action=redirect&bpo=18395

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21233

   (7) https://bugs.python.org/issue?@action=redirect&bpo=20942


File: python.info,  Node: Documentation<83>,  Next: Tests<90>,  Prev: C API<78>,  Up: Python 3 5 0 alpha 1

1.23.121.6 Documentation
........................

   - bpo-19548(1): Update the codecs module documentation to better
     cover the distinction between text encodings and other codecs,
     together with other clarifications.  Patch by Martin Panter.

   - bpo-22394(2): Doc/Makefile now supports ‘make venv
     PYTHON=../python’ to create a venv for generating the
     documentation, e.g., ‘make html PYTHON=venv/bin/python3’.

   - bpo-21514(3): The documentation of the json module now refers to
     new JSON RFC 7159 instead of obsoleted RFC 4627.

   - bpo-21777(4): The binary sequence methods on bytes and bytearray
     are now documented explicitly, rather than assuming users will be
     able to derive the expected behaviour from the behaviour of the
     corresponding str methods.

   - bpo-6916(5): undocument deprecated asynchat.fifo class.

   - bpo-17386(6): Expanded functionality of the ‘Doc/make.bat’ script
     to make it much more comparable to ‘Doc/Makefile’.

   - bpo-21312(7): Update the thread_foobar.h template file to include
     newer threading APIs.  Patch by Jack McCracken.

   - bpo-21043(8): Remove the recommendation for specific CA
     organizations and to mention the ability to load the OS
     certificates.

   - bpo-20765(9): Add missing documentation for PurePath.with_name()
     and PurePath.with_suffix().

   - bpo-19407(10): New package installation and distribution guides
     based on the Python Packaging Authority tools.  Existing guides
     have been retained as legacy links from the distutils docs, as they
     still contain some required reference material for tool developers
     that isn’t recorded anywhere else.

   - bpo-19697(11): Document cases where __main__.__spec__ is None.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=19548

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22394

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21514

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21777

   (5) https://bugs.python.org/issue?@action=redirect&bpo=6916

   (6) https://bugs.python.org/issue?@action=redirect&bpo=17386

   (7) https://bugs.python.org/issue?@action=redirect&bpo=21312

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21043

   (9) https://bugs.python.org/issue?@action=redirect&bpo=20765

   (10) https://bugs.python.org/issue?@action=redirect&bpo=19407

   (11) https://bugs.python.org/issue?@action=redirect&bpo=19697


File: python.info,  Node: Tests<90>,  Next: Tools/Demos<54>,  Prev: Documentation<83>,  Up: Python 3 5 0 alpha 1

1.23.121.7 Tests
................

   - bpo-18982(1): Add tests for CLI of the calendar module.

   - bpo-19548(2): Added some additional checks to test_codecs to ensure
     that statements in the updated documentation remain accurate.
     Patch by Martin Panter.

   - bpo-22838(3): All test_re tests now work with unittest test
     discovery.

   - bpo-22173(4): Update lib2to3 tests to use unittest test discovery.

   - bpo-16000(5): Convert test_curses to use unittest.

   - bpo-21456(6): Skip two tests in test_urllib2net.py if _ssl module
     not present.  Patch by Remi Pointel.

   - bpo-20746(7): Fix test_pdb to run in refleak mode (-R). Patch by
     Xavier de Gaye.

   - bpo-22060(8): test_ctypes has been somewhat cleaned up and
     simplified; it now uses unittest test discovery to find its tests.

   - bpo-22104(9): regrtest.py no longer holds a reference to the suite
     of tests loaded from test modules that don’t define test_main().

   - bpo-22111(10): Assorted cleanups in test_imaplib.  Patch by Milan
     Oberkirch.

   - bpo-22002(11): Added ‘load_package_tests’ function to test.support
     and used it to implement/augment test discovery in test_asyncio,
     test_email, test_importlib, test_json, and test_tools.

   - bpo-21976(12): Fix test_ssl to accept LibreSSL version strings.
     Thanks to William Orr.

   - bpo-21918(13): Converted test_tools from a module to a package
     containing separate test files for each tested script.

   - bpo-9554(14): Use modern unittest features in test_argparse.
     Initial patch by Denver Coneybeare and Radu Voicilas.

   - bpo-20155(15): Changed HTTP method names in failing tests in
     test_httpservers so that packet filtering software (specifically
     Windows Base Filtering Engine) does not interfere with the
     transaction semantics expected by the tests.

   - bpo-19493(16): Refactored the ctypes test package to skip tests
     explicitly rather than silently.

   - bpo-18492(17): All resources are now allowed when tests are not run
     by regrtest.py.

   - bpo-21634(18): Fix pystone micro-benchmark: use floor division
     instead of true division to benchmark integers instead of
     floating-point numbers.  Set pystone version to 1.2.  Patch written
     by Lennart Regebro.

   - bpo-21605(19): Added tests for Tkinter images.

   - bpo-21493(20): Added test for ntpath.expanduser().  Original patch
     by Claudiu Popa.

   - bpo-19925(21): Added tests for the spwd module.  Original patch by
     Vajrasky Kok.

   - bpo-21522(22): Added Tkinter tests for Listbox.itemconfigure(),
     PanedWindow.paneconfigure(), and Menu.entryconfigure().

   - bpo-17756(23): Fix test_code test when run from the installed
     location.

   - bpo-17752(24): Fix distutils tests when run from the installed
     location.

   - bpo-18604(25): Consolidated checks for GUI availability.  All
     platforms now at least check whether Tk can be instantiated when
     the GUI resource is requested.

   - bpo-21275(26): Fix a socket test on KFreeBSD.

   - bpo-21223(27): Pass test_site/test_startup_imports when some of the
     extensions are built as builtins.

   - bpo-20635(28): Added tests for Tk geometry managers.

   - Add test case for freeze.

   - bpo-20743(29): Fix a reference leak in test_tcl.

   - bpo-21097(30): Move test_namespace_pkgs into test_importlib.

   - bpo-21503(31): Use test_both() consistently in test_importlib.

   - bpo-20939(32): Avoid various network test failures due to new
     redirect of ‘http://www.python.org/’ to ‘https://www.python.org’:
     use ‘http://www.example.com’ instead.

   - bpo-20668(33): asyncio tests no longer rely on tests.txt file.
     (Patch by Vajrasky Kok)

   - bpo-21093(34): Prevent failures of ctypes test_macholib on OS X if
     a copy of libz exists in $HOME/lib or /usr/local/lib.

   - bpo-22770(35): Prevent some Tk segfaults on OS X when running gui
     tests.

   - bpo-23211(36): Workaround test_logging failure on some OS X 10.6
     systems.

   - bpo-23345(37): Prevent test_ssl failures with large OpenSSL patch
     level values (like 0.9.8zc).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18982

   (2) https://bugs.python.org/issue?@action=redirect&bpo=19548

   (3) https://bugs.python.org/issue?@action=redirect&bpo=22838

   (4) https://bugs.python.org/issue?@action=redirect&bpo=22173

   (5) https://bugs.python.org/issue?@action=redirect&bpo=16000

   (6) https://bugs.python.org/issue?@action=redirect&bpo=21456

   (7) https://bugs.python.org/issue?@action=redirect&bpo=20746

   (8) https://bugs.python.org/issue?@action=redirect&bpo=22060

   (9) https://bugs.python.org/issue?@action=redirect&bpo=22104

   (10) https://bugs.python.org/issue?@action=redirect&bpo=22111

   (11) https://bugs.python.org/issue?@action=redirect&bpo=22002

   (12) https://bugs.python.org/issue?@action=redirect&bpo=21976

   (13) https://bugs.python.org/issue?@action=redirect&bpo=21918

   (14) https://bugs.python.org/issue?@action=redirect&bpo=9554

   (15) https://bugs.python.org/issue?@action=redirect&bpo=20155

   (16) https://bugs.python.org/issue?@action=redirect&bpo=19493

   (17) https://bugs.python.org/issue?@action=redirect&bpo=18492

   (18) https://bugs.python.org/issue?@action=redirect&bpo=21634

   (19) https://bugs.python.org/issue?@action=redirect&bpo=21605

   (20) https://bugs.python.org/issue?@action=redirect&bpo=21493

   (21) https://bugs.python.org/issue?@action=redirect&bpo=19925

   (22) https://bugs.python.org/issue?@action=redirect&bpo=21522

   (23) https://bugs.python.org/issue?@action=redirect&bpo=17756

   (24) https://bugs.python.org/issue?@action=redirect&bpo=17752

   (25) https://bugs.python.org/issue?@action=redirect&bpo=18604

   (26) https://bugs.python.org/issue?@action=redirect&bpo=21275

   (27) https://bugs.python.org/issue?@action=redirect&bpo=21223

   (28) https://bugs.python.org/issue?@action=redirect&bpo=20635

   (29) https://bugs.python.org/issue?@action=redirect&bpo=20743

   (30) https://bugs.python.org/issue?@action=redirect&bpo=21097

   (31) https://bugs.python.org/issue?@action=redirect&bpo=21503

   (32) https://bugs.python.org/issue?@action=redirect&bpo=20939

   (33) https://bugs.python.org/issue?@action=redirect&bpo=20668

   (34) https://bugs.python.org/issue?@action=redirect&bpo=21093

   (35) https://bugs.python.org/issue?@action=redirect&bpo=22770

   (36) https://bugs.python.org/issue?@action=redirect&bpo=23211

   (37) https://bugs.python.org/issue?@action=redirect&bpo=23345


File: python.info,  Node: Tools/Demos<54>,  Next: Windows<81>,  Prev: Tests<90>,  Up: Python 3 5 0 alpha 1

1.23.121.8 Tools/Demos
......................

   - bpo-22314(1): pydoc now works when the LINES environment variable
     is set.

   - bpo-22615(2): Argument Clinic now supports the “type” argument for
     the int converter.  This permits using the int converter with enums
     and typedefs.

   - bpo-20076(3): The makelocalealias.py script no longer ignores UTF-8
     mapping.

   - bpo-20079(4): The makelocalealias.py script now can parse the
     SUPPORTED file from glibc sources and supports command line options
     for source paths.

   - bpo-22201(5): Command-line interface of the zipfile module now
     correctly extracts ZIP files with directory entries.  Patch by Ryan
     Wilson.

   - bpo-22120(6): For functions using an unsigned integer return
     converter, Argument Clinic now generates a cast to that type for
     the comparison to -1 in the generated code.  (This suppresses a
     compilation warning.)

   - bpo-18974(7): Tools/scripts/diff.py now uses argparse instead of
     optparse.

   - bpo-21906(8): Make Tools/scripts/md5sum.py work in Python 3.  Patch
     by Zachary Ware.

   - bpo-21629(9): Fix Argument Clinic’s “–converters” feature.

   - Add support for ‘yield from’ to 2to3.

   - Add support for the PEP 465(10) matrix multiplication operator to
     2to3.

   - bpo-16047(11): Fix module exception list and __file__ handling in
     freeze.  Patch by Meador Inge.

   - bpo-11824(12): Consider ABI tags in freeze.  Patch by Meador Inge.

   - bpo-20535(13): PYTHONWARNING no longer affects the run_tests.py
     script.  Patch by Arfrever Frehtes Taifersar Arahesis.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=22314

   (2) https://bugs.python.org/issue?@action=redirect&bpo=22615

   (3) https://bugs.python.org/issue?@action=redirect&bpo=20076

   (4) https://bugs.python.org/issue?@action=redirect&bpo=20079

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22201

   (6) https://bugs.python.org/issue?@action=redirect&bpo=22120

   (7) https://bugs.python.org/issue?@action=redirect&bpo=18974

   (8) https://bugs.python.org/issue?@action=redirect&bpo=21906

   (9) https://bugs.python.org/issue?@action=redirect&bpo=21629

   (10) https://peps.python.org/pep-0465/

   (11) https://bugs.python.org/issue?@action=redirect&bpo=16047

   (12) https://bugs.python.org/issue?@action=redirect&bpo=11824

   (13) https://bugs.python.org/issue?@action=redirect&bpo=20535


File: python.info,  Node: Windows<81>,  Prev: Tools/Demos<54>,  Up: Python 3 5 0 alpha 1

1.23.121.9 Windows
..................

   - bpo-23260(1): Update Windows installer

   - The bundled version of Tcl/Tk has been updated to 8.6.3.  The most
     visible result of this change is the addition of new native file
     dialogs when running on Windows Vista or newer.  See Tcl/Tk’s TIP
     432 for more information.  Also, this version of Tcl/Tk includes
     support for Windows 10.

   - bpo-17896(2): The Windows build scripts now expect external library
     sources to be in ‘PCbuild\..\externals’ rather than
     ‘PCbuild\..\..’.

   - bpo-17717(3): The Windows build scripts now use a copy of NASM
     pulled from svn.python.org to build OpenSSL.

   - bpo-21907(4): Improved the batch scripts provided for building
     Python.

   - bpo-22644(5): The bundled version of OpenSSL has been updated to
     1.0.1j.

   - bpo-10747(6): Use versioned labels in the Windows start menu.
     Patch by Olive Kilburn.

   - bpo-22980(7): .pyd files with a version and platform tag (for
     example, “.cp35-win32.pyd”) will now be loaded in preference to
     those without tags.

'(For information about older versions, consult the HISTORY file.)'

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=23260

   (2) https://bugs.python.org/issue?@action=redirect&bpo=17896

   (3) https://bugs.python.org/issue?@action=redirect&bpo=17717

   (4) https://bugs.python.org/issue?@action=redirect&bpo=21907

   (5) https://bugs.python.org/issue?@action=redirect&bpo=22644

   (6) https://bugs.python.org/issue?@action=redirect&bpo=10747

   (7) https://bugs.python.org/issue?@action=redirect&bpo=22980


File: python.info,  Node: The Python Tutorial,  Next: Python Setup and Usage,  Prev: What’s New in Python,  Up: Top

2 The Python Tutorial
*********************

     Tip: This tutorial is designed for 'programmers' that are new to
     the Python language, 'not' 'beginners' who are new to programming.

Python is an easy to learn, powerful programming language.  It has
efficient high-level data structures and a simple but effective approach
to object-oriented programming.  Python’s elegant syntax and dynamic
typing, together with its interpreted nature, make it an ideal language
for scripting and rapid application development in many areas on most
platforms.

The Python interpreter and the extensive standard library are freely
available in source or binary form for all major platforms from the
Python website, ‘https://www.python.org/’, and may be freely
distributed.  The same site also contains distributions of and pointers
to many free third party Python modules, programs and tools, and
additional documentation.

The Python interpreter is easily extended with new functions and data
types implemented in C or C++ (or other languages callable from C).
Python is also suitable as an extension language for customizable
applications.

This tutorial introduces the reader informally to the basic concepts and
features of the Python language and system.  Be aware that it expects
you to have a basic understanding of programming in general.  It helps
to have a Python interpreter handy for hands-on experience, but all
examples are self-contained, so the tutorial can be read off-line as
well.

For a description of standard objects and modules, see *note The Python
Standard Library: 144.  *note The Python Language Reference: 145. gives
a more formal definition of the language.  To write extensions in C or
C++, read *note Extending and Embedding the Python Interpreter: 1d6e.
and *note Python/C API Reference Manual: 1d6f.  There are also several
books covering Python in depth.

This tutorial does not attempt to be comprehensive and cover every
single feature, or even every commonly used feature.  Instead, it
introduces many of Python’s most noteworthy features, and will give you
a good idea of the language’s flavor and style.  After reading it, you
will be able to read and write Python modules and programs, and you will
be ready to learn more about the various Python library modules
described in *note The Python Standard Library: 144.

The *note Glossary: 1d70. is also worth going through.

* Menu:

* Whetting Your Appetite::
* Using the Python Interpreter::
* An Informal Introduction to Python::
* More Control Flow Tools::
* Data Structures::
* Modules: Modules<2>.
* Input and Output::
* Errors and Exceptions::
* Classes::
* Brief tour of the standard library::
* Brief Tour of the Standard Library — Part II::
* Virtual Environments and Packages::
* What Now?::
* Interactive Input Editing and History Substitution::
* Floating-Point Arithmetic; Issues and Limitations: Floating-Point Arithmetic Issues and Limitations.
* Appendix::


File: python.info,  Node: Whetting Your Appetite,  Next: Using the Python Interpreter,  Up: The Python Tutorial

2.1 Whetting Your Appetite
==========================

If you do much work on computers, eventually you find that there’s some
task you’d like to automate.  For example, you may wish to perform a
search-and-replace over a large number of text files, or rename and
rearrange a bunch of photo files in a complicated way.  Perhaps you’d
like to write a small custom database, or a specialized GUI application,
or a simple game.

If you’re a professional software developer, you may have to work with
several C/C++/Java libraries but find the usual
write/compile/test/re-compile cycle is too slow.  Perhaps you’re writing
a test suite for such a library and find writing the testing code a
tedious task.  Or maybe you’ve written a program that could use an
extension language, and you don’t want to design and implement a whole
new language for your application.

Python is just the language for you.

You could write a Unix shell script or Windows batch files for some of
these tasks, but shell scripts are best at moving around files and
changing text data, not well-suited for GUI applications or games.  You
could write a C/C++/Java program, but it can take a lot of development
time to get even a first-draft program.  Python is simpler to use,
available on Windows, macOS, and Unix operating systems, and will help
you get the job done more quickly.

Python is simple to use, but it is a real programming language, offering
much more structure and support for large programs than shell scripts or
batch files can offer.  On the other hand, Python also offers much more
error checking than C, and, being a 'very-high-level language', it has
high-level data types built in, such as flexible arrays and
dictionaries.  Because of its more general data types Python is
applicable to a much larger problem domain than Awk or even Perl, yet
many things are at least as easy in Python as in those languages.

Python allows you to split your program into modules that can be reused
in other Python programs.  It comes with a large collection of standard
modules that you can use as the basis of your programs — or as examples
to start learning to program in Python.  Some of these modules provide
things like file I/O, system calls, sockets, and even interfaces to
graphical user interface toolkits like Tk.

Python is an interpreted language, which can save you considerable time
during program development because no compilation and linking is
necessary.  The interpreter can be used interactively, which makes it
easy to experiment with features of the language, to write throw-away
programs, or to test functions during bottom-up program development.  It
is also a handy desk calculator.

Python enables programs to be written compactly and readably.  Programs
written in Python are typically much shorter than equivalent C, C++, or
Java programs, for several reasons:

   * the high-level data types allow you to express complex operations
     in a single statement;

   * statement grouping is done by indentation instead of beginning and
     ending brackets;

   * no variable or argument declarations are necessary.

Python is 'extensible': if you know how to program in C it is easy to
add a new built-in function or module to the interpreter, either to
perform critical operations at maximum speed, or to link Python programs
to libraries that may only be available in binary form (such as a
vendor-specific graphics library).  Once you are really hooked, you can
link the Python interpreter into an application written in C and use it
as an extension or command language for that application.

By the way, the language is named after the BBC show “Monty Python’s
Flying Circus” and has nothing to do with reptiles.  Making references
to Monty Python skits in documentation is not only allowed, it is
encouraged!

Now that you are all excited about Python, you’ll want to examine it in
some more detail.  Since the best way to learn a language is to use it,
the tutorial invites you to play with the Python interpreter as you
read.

In the next chapter, the mechanics of using the interpreter are
explained.  This is rather mundane information, but essential for trying
out the examples shown later.

The rest of the tutorial introduces various features of the Python
language and system through examples, beginning with simple expressions,
statements and data types, through functions and modules, and finally
touching upon advanced concepts like exceptions and user-defined
classes.


File: python.info,  Node: Using the Python Interpreter,  Next: An Informal Introduction to Python,  Prev: Whetting Your Appetite,  Up: The Python Tutorial

2.2 Using the Python Interpreter
================================

* Menu:

* Invoking the Interpreter::
* The Interpreter and Its Environment::


File: python.info,  Node: Invoking the Interpreter,  Next: The Interpreter and Its Environment,  Up: Using the Python Interpreter

2.2.1 Invoking the Interpreter
------------------------------

The Python interpreter is usually installed as
‘/usr/local/bin/python3.13’ on those machines where it is available;
putting ‘/usr/local/bin’ in your Unix shell’s search path makes it
possible to start it by typing the command:

     python3.13

to the shell.  (1)  Since the choice of the directory where the
interpreter lives is an installation option, other places are possible;
check with your local Python guru or system administrator.  (E.g.,
‘/usr/local/python’ is a popular alternative location.)

On Windows machines where you have installed Python from the *note
Microsoft Store: 1d7a, the ‘python3.13’ command will be available.  If
you have the *note py.exe launcher: 5c1. installed, you can use the ‘py’
command.  See *note Excursus; Setting environment variables: 1d7b. for
other ways to launch Python.

Typing an end-of-file character (‘Control’-‘D’ on Unix, ‘Control’-‘Z’ on
Windows) at the primary prompt causes the interpreter to exit with a
zero exit status.  If that doesn’t work, you can exit the interpreter by
typing the following command: ‘quit()’.

The interpreter’s line-editing features include interactive editing,
history substitution and code completion on most systems.  Perhaps the
quickest check to see whether command line editing is supported is
typing a word in on the Python prompt, then pressing Left arrow (or
‘Control’-‘b’).  If the cursor moves, you have command line editing; see
Appendix *note Interactive Input Editing and History Substitution: 1d7c.
for an introduction to the keys.  If nothing appears to happen, or if a
sequence like ‘^[[D’ or ‘^B’ appears, command line editing isn’t
available; you’ll only be able to use backspace to remove characters
from the current line.

The interpreter operates somewhat like the Unix shell: when called with
standard input connected to a tty device, it reads and executes commands
interactively; when called with a file name argument or with a file as
standard input, it reads and executes a 'script' from that file.

A second way of starting the interpreter is ‘python -c command [arg]
...’, which executes the statement(s) in 'command', analogous to the
shell’s *note -c: 5e3. option.  Since Python statements often contain
spaces or other characters that are special to the shell, it is usually
advised to quote 'command' in its entirety.

Some Python modules are also useful as scripts.  These can be invoked
using ‘python -m module [arg] ...’, which executes the source file for
'module' as if you had spelled out its full name on the command line.

When a script file is used, it is sometimes useful to be able to run the
script and enter interactive mode afterwards.  This can be done by
passing *note -i: 152a. before the script.

All command line options are described in *note Command line and
environment: 1b4f.

* Menu:

* Argument Passing::
* Interactive Mode::

   ---------- Footnotes ----------

   (1) On Unix, the Python 3.x interpreter is by default not installed
with the executable named ‘python’, so that it does not conflict with a
simultaneously installed Python 2.x executable.


File: python.info,  Node: Argument Passing,  Next: Interactive Mode,  Up: Invoking the Interpreter

2.2.1.1 Argument Passing
........................

When known to the interpreter, the script name and additional arguments
thereafter are turned into a list of strings and assigned to the ‘argv’
variable in the ‘sys’ module.  You can access this list by executing
‘import sys’.  The length of the list is at least one; when no script
and no arguments are given, ‘sys.argv[0]’ is an empty string.  When the
script name is given as ‘'-'’ (meaning standard input), ‘sys.argv[0]’ is
set to ‘'-'’.  When *note -c: 5e3. 'command' is used, ‘sys.argv[0]’ is
set to ‘'-c'’.  When *note -m: 5e4. 'module' is used, ‘sys.argv[0]’ is
set to the full name of the located module.  Options found after ‘-c’
'command' or ‘-m’ 'module' are not consumed by the Python interpreter’s
option processing but left in ‘sys.argv’ for the command or module to
handle.


File: python.info,  Node: Interactive Mode,  Prev: Argument Passing,  Up: Invoking the Interpreter

2.2.1.2 Interactive Mode
........................

When commands are read from a tty, the interpreter is said to be in
'interactive mode'.  In this mode it prompts for the next command with
the 'primary prompt', usually three greater-than signs (‘>>>’); for
continuation lines it prompts with the 'secondary prompt', by default
three dots (‘...’).  The interpreter prints a welcome message stating
its version number and a copyright notice before printing the first
prompt:

     $ python3.13
     Python 3.13 (default, April 4 2023, 09:25:04)
     [GCC 10.2.0] on linux
     Type "help", "copyright", "credits" or "license" for more information.
     >>>

Continuation lines are needed when entering a multi-line construct.  As
an example, take a look at this *note if: 2f3. statement:

     >>> the_world_is_flat = True
     >>> if the_world_is_flat:
     ...     print("Be careful not to fall off!")
     ...
     Be careful not to fall off!

For more on interactive mode, see *note Interactive Mode: 16f.


File: python.info,  Node: The Interpreter and Its Environment,  Prev: Invoking the Interpreter,  Up: Using the Python Interpreter

2.2.2 The Interpreter and Its Environment
-----------------------------------------

* Menu:

* Source Code Encoding::


File: python.info,  Node: Source Code Encoding,  Up: The Interpreter and Its Environment

2.2.2.1 Source Code Encoding
............................

By default, Python source files are treated as encoded in UTF-8.  In
that encoding, characters of most languages in the world can be used
simultaneously in string literals, identifiers and comments — although
the standard library only uses ASCII characters for identifiers, a
convention that any portable code should follow.  To display all these
characters properly, your editor must recognize that the file is UTF-8,
and it must use a font that supports all the characters in the file.

To declare an encoding other than the default one, a special comment
line should be added as the 'first' line of the file.  The syntax is as
follows:

     # -*- coding: encoding -*-

where 'encoding' is one of the valid *note codecs: 1b. supported by
Python.

For example, to declare that Windows-1252 encoding is to be used, the
first line of your source code file should be:

     # -*- coding: cp1252 -*-

One exception to the 'first line' rule is when the source code starts
with a *note UNIX “shebang” line: 1d84.  In this case, the encoding
declaration should be added as the second line of the file.  For
example:

     #!/usr/bin/env python3
     # -*- coding: cp1252 -*-


File: python.info,  Node: An Informal Introduction to Python,  Next: More Control Flow Tools,  Prev: Using the Python Interpreter,  Up: The Python Tutorial

2.3 An Informal Introduction to Python
======================================

In the following examples, input and output are distinguished by the
presence or absence of prompts (*note >>>: 16c. and *note …: 16d.): to
repeat the example, you must type everything after the prompt, when the
prompt appears; lines that do not begin with a prompt are output from
the interpreter.  Note that a secondary prompt on a line by itself in an
example means you must type a blank line; this is used to end a
multi-line command.

Many of the examples in this manual, even those entered at the
interactive prompt, include comments.  Comments in Python start with the
hash character, ‘#’, and extend to the end of the physical line.  A
comment may appear at the start of a line or following whitespace or
code, but not within a string literal.  A hash character within a string
literal is just a hash character.  Since comments are to clarify code
and are not interpreted by Python, they may be omitted when typing in
examples.

Some examples:

     # this is the first comment
     spam = 1  # and this is the second comment
               # ... and now a third!
     text = "# This is not a comment because it's inside quotes."

* Menu:

* Using Python as a Calculator::
* First Steps Towards Programming::


File: python.info,  Node: Using Python as a Calculator,  Next: First Steps Towards Programming,  Up: An Informal Introduction to Python

2.3.1 Using Python as a Calculator
----------------------------------

Let’s try some simple Python commands.  Start the interpreter and wait
for the primary prompt, ‘>>>’.  (It shouldn’t take long.)

* Menu:

* Numbers::
* Text::
* Lists::


File: python.info,  Node: Numbers,  Next: Text,  Up: Using Python as a Calculator

2.3.1.1 Numbers
...............

The interpreter acts as a simple calculator: you can type an expression
into it and it will write the value.  Expression syntax is
straightforward: the operators ‘+’, ‘-’, ‘*’ and ‘/’ can be used to
perform arithmetic; parentheses (‘()’) can be used for grouping.  For
example:

     >>> 2 + 2
     4
     >>> 50 - 5*6
     20
     >>> (50 - 5*6) / 4
     5.0
     >>> 8 / 5  # division always returns a floating-point number
     1.6

The integer numbers (e.g.  ‘2’, ‘4’, ‘20’) have type *note int: 257, the
ones with a fractional part (e.g.  ‘5.0’, ‘1.6’) have type *note float:
2f7.  We will see more about numeric types later in the tutorial.

Division (‘/’) always returns a float.  To do *note floor division: 94e.
and get an integer result you can use the ‘//’ operator; to calculate
the remainder you can use ‘%’:

     >>> 17 / 3  # classic division returns a float
     5.666666666666667
     >>>
     >>> 17 // 3  # floor division discards the fractional part
     5
     >>> 17 % 3  # the % operator returns the remainder of the division
     2
     >>> 5 * 3 + 2  # floored quotient * divisor + remainder
     17

With Python, it is possible to use the ‘**’ operator to calculate powers
(1):

     >>> 5 ** 2  # 5 squared
     25
     >>> 2 ** 7  # 2 to the power of 7
     128

The equal sign (‘=’) is used to assign a value to a variable.
Afterwards, no result is displayed before the next interactive prompt:

     >>> width = 20
     >>> height = 5 * 9
     >>> width * height
     900

If a variable is not “defined” (assigned a value), trying to use it will
give you an error:

     >>> n  # try to access an undefined variable
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     NameError: name 'n' is not defined

There is full support for floating point; operators with mixed type
operands convert the integer operand to floating point:

     >>> 4 * 3.75 - 1
     14.0

In interactive mode, the last printed expression is assigned to the
variable ‘_’.  This means that when you are using Python as a desk
calculator, it is somewhat easier to continue calculations, for example:

     >>> tax = 12.5 / 100
     >>> price = 100.50
     >>> price * tax
     12.5625
     >>> price + _
     113.0625
     >>> round(_, 2)
     113.06

This variable should be treated as read-only by the user.  Don’t
explicitly assign a value to it — you would create an independent local
variable with the same name masking the built-in variable with its magic
behavior.

In addition to *note int: 257. and *note float: 2f7, Python supports
other types of numbers, such as *note Decimal: 29d. and *note Fraction:
1e7.  Python also has built-in support for *note complex numbers: 1d8d,
and uses the ‘j’ or ‘J’ suffix to indicate the imaginary part (e.g.
‘3+5j’).

   ---------- Footnotes ----------

   (1) Since ‘**’ has higher precedence than ‘-’, ‘-3**2’ will be
interpreted as ‘-(3**2)’ and thus result in ‘-9’.  To avoid this and get
‘9’, you can use ‘(-3)**2’.


File: python.info,  Node: Text,  Next: Lists,  Prev: Numbers,  Up: Using Python as a Calculator

2.3.1.2 Text
............

Python can manipulate text (represented by type *note str: 44f,
so-called “strings”) as well as numbers.  This includes characters
“‘!’”, words “‘rabbit’”, names “‘Paris’”, sentences “‘Got your back.’”,
etc.  “‘Yay! :)’”.  They can be enclosed in single quotes (‘'...'’) or
double quotes (‘"..."’) with the same result (1).

     >>> 'spam eggs'  # single quotes
     'spam eggs'
     >>> "Paris rabbit got your back :)! Yay!"  # double quotes
     'Paris rabbit got your back :)! Yay!'
     >>> '1975'  # digits and numerals enclosed in quotes are also strings
     '1975'

To quote a quote, we need to “escape” it, by preceding it with ‘\’.
Alternatively, we can use the other type of quotation marks:

     >>> 'doesn\'t'  # use \' to escape the single quote...
     "doesn't"
     >>> "doesn't"  # ...or use double quotes instead
     "doesn't"
     >>> '"Yes," they said.'
     '"Yes," they said.'
     >>> "\"Yes,\" they said."
     '"Yes," they said.'
     >>> '"Isn\'t," they said.'
     '"Isn\'t," they said.'

In the Python shell, the string definition and output string can look
different.  The *note print(): fae. function produces a more readable
output, by omitting the enclosing quotes and by printing escaped and
special characters:

     >>> s = 'First line.\nSecond line.'  # \n means newline
     >>> s  # without print(), special characters are included in the string
     'First line.\nSecond line.'
     >>> print(s)  # with print(), special characters are interpreted, so \n produces new line
     First line.
     Second line.

If you don’t want characters prefaced by ‘\’ to be interpreted as
special characters, you can use 'raw strings' by adding an ‘r’ before
the first quote:

     >>> print('C:\this\name')  # here \t means tab, \n means newline
     C:      his
     ame
     >>> print(r'C:\this\name')  # note the r before the quote
     C:\this\name

There is one subtle aspect to raw strings: a raw string may not end in
an odd number of ‘\’ characters; see *note the FAQ entry: 1d90. for more
information and workarounds.

String literals can span multiple lines.  One way is using
triple-quotes: ‘"""..."""’ or ‘'''...'''’.  End-of-line characters are
automatically included in the string, but it’s possible to prevent this
by adding a ‘\’ at the end of the line.  In the following example, the
initial newline is not included:

     >>> print("""\
     ... Usage: thingy [OPTIONS]
     ...      -h                        Display this usage message
     ...      -H hostname               Hostname to connect to
     ... """)
     Usage: thingy [OPTIONS]
          -h                        Display this usage message
          -H hostname               Hostname to connect to

     >>>

Strings can be concatenated (glued together) with the ‘+’ operator, and
repeated with ‘*’:

     >>> # 3 times 'un', followed by 'ium'
     >>> 3 * 'un' + 'ium'
     'unununium'

Two or more 'string literals' (i.e.  the ones enclosed between quotes)
next to each other are automatically concatenated.

     >>> 'Py' 'thon'
     'Python'

This feature is particularly useful when you want to break long strings:

     >>> text = ('Put several strings within parentheses '
     ...         'to have them joined together.')
     >>> text
     'Put several strings within parentheses to have them joined together.'

This only works with two literals though, not with variables or
expressions:

     >>> prefix = 'Py'
     >>> prefix 'thon'  # can't concatenate a variable and a string literal
       File "<stdin>", line 1
         prefix 'thon'
                ^^^^^^
     SyntaxError: invalid syntax
     >>> ('un' * 3) 'ium'
       File "<stdin>", line 1
         ('un' * 3) 'ium'
                    ^^^^^
     SyntaxError: invalid syntax

If you want to concatenate variables or a variable and a literal, use
‘+’:

     >>> prefix + 'thon'
     'Python'

Strings can be 'indexed' (subscripted), with the first character having
index 0.  There is no separate character type; a character is simply a
string of size one:

     >>> word = 'Python'
     >>> word[0]  # character in position 0
     'P'
     >>> word[5]  # character in position 5
     'n'

Indices may also be negative numbers, to start counting from the right:

     >>> word[-1]  # last character
     'n'
     >>> word[-2]  # second-last character
     'o'
     >>> word[-6]
     'P'

Note that since -0 is the same as 0, negative indices start from -1.

In addition to indexing, 'slicing' is also supported.  While indexing is
used to obtain individual characters, 'slicing' allows you to obtain a
substring:

     >>> word[0:2]  # characters from position 0 (included) to 2 (excluded)
     'Py'
     >>> word[2:5]  # characters from position 2 (included) to 5 (excluded)
     'tho'

Slice indices have useful defaults; an omitted first index defaults to
zero, an omitted second index defaults to the size of the string being
sliced.

     >>> word[:2]   # character from the beginning to position 2 (excluded)
     'Py'
     >>> word[4:]   # characters from position 4 (included) to the end
     'on'
     >>> word[-2:]  # characters from the second-last (included) to the end
     'on'

Note how the start is always included, and the end always excluded.
This makes sure that ‘s[:i] + s[i:]’ is always equal to ‘s’:

     >>> word[:2] + word[2:]
     'Python'
     >>> word[:4] + word[4:]
     'Python'

One way to remember how slices work is to think of the indices as
pointing 'between' characters, with the left edge of the first character
numbered 0.  Then the right edge of the last character of a string of
'n' characters has index 'n', for example:

      +---+---+---+---+---+---+
      | P | y | t | h | o | n |
      +---+---+---+---+---+---+
      0   1   2   3   4   5   6
     -6  -5  -4  -3  -2  -1

The first row of numbers gives the position of the indices 0…6 in the
string; the second row gives the corresponding negative indices.  The
slice from 'i' to 'j' consists of all characters between the edges
labeled 'i' and 'j', respectively.

For non-negative indices, the length of a slice is the difference of the
indices, if both are within bounds.  For example, the length of
‘word[1:3]’ is 2.

Attempting to use an index that is too large will result in an error:

     >>> word[42]  # the word only has 6 characters
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     IndexError: string index out of range

However, out of range slice indexes are handled gracefully when used for
slicing:

     >>> word[4:42]
     'on'
     >>> word[42:]
     ''

Python strings cannot be changed — they are *note immutable: 1d91.
Therefore, assigning to an indexed position in the string results in an
error:

     >>> word[0] = 'J'
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: 'str' object does not support item assignment
     >>> word[2:] = 'py'
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: 'str' object does not support item assignment

If you need a different string, you should create a new one:

     >>> 'J' + word[1:]
     'Jython'
     >>> word[:2] + 'py'
     'Pypy'

The built-in function *note len(): 631. returns the length of a string:

     >>> s = 'supercalifragilisticexpialidocious'
     >>> len(s)
     34

See also
........

*note Text Sequence Type — str: 1d92.

     Strings are examples of 'sequence types', and support the common
     operations supported by such types.

*note String Methods: 1d93.

     Strings support a large number of methods for basic transformations
     and searching.

*note f-strings: 9b4.

     String literals that have embedded expressions.

*note Format string syntax: 13e8.

     Information about string formatting with *note str.format(): 624.

*note printf-style String Formatting: 6cf.

     The old formatting operations invoked when strings are the left
     operand of the ‘%’ operator are described in more detail here.

   ---------- Footnotes ----------

   (1) Unlike other languages, special characters such as ‘\n’ have the
same meaning with both single (‘'...'’) and double (‘"..."’) quotes.
The only difference between the two is that within single quotes you
don’t need to escape ‘"’ (but you have to escape ‘\'’) and vice versa.


File: python.info,  Node: Lists,  Prev: Text,  Up: Using Python as a Calculator

2.3.1.3 Lists
.............

Python knows a number of 'compound' data types, used to group together
other values.  The most versatile is the 'list', which can be written as
a list of comma-separated values (items) between square brackets.  Lists
might contain items of different types, but usually the items all have
the same type.

     >>> squares = [1, 4, 9, 16, 25]
     >>> squares
     [1, 4, 9, 16, 25]

Like strings (and all other built-in *note sequence: 4f4. types), lists
can be indexed and sliced:

     >>> squares[0]  # indexing returns the item
     1
     >>> squares[-1]
     25
     >>> squares[-3:]  # slicing returns a new list
     [9, 16, 25]

Lists also support operations like concatenation:

     >>> squares + [36, 49, 64, 81, 100]
     [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Unlike strings, which are *note immutable: 1d91, lists are a *note
mutable: 1d96. type, i.e.  it is possible to change their content:

     >>> cubes = [1, 8, 27, 65, 125]  # something's wrong here
     >>> 4 ** 3  # the cube of 4 is 64, not 65!
     64
     >>> cubes[3] = 64  # replace the wrong value
     >>> cubes
     [1, 8, 27, 64, 125]

You can also add new items at the end of the list, by using the *note
list.append(): 6d0. 'method' (we will see more about methods later):

     >>> cubes.append(216)  # add the cube of 6
     >>> cubes.append(7 ** 3)  # and the cube of 7
     >>> cubes
     [1, 8, 27, 64, 125, 216, 343]

Simple assignment in Python never copies data.  When you assign a list
to a variable, the variable refers to the 'existing list'.  Any changes
you make to the list through one variable will be seen through all other
variables that refer to it.:

     >>> rgb = ["Red", "Green", "Blue"]
     >>> rgba = rgb
     >>> id(rgb) == id(rgba)  # they reference the same object
     True
     >>> rgba.append("Alph")
     >>> rgb
     ["Red", "Green", "Blue", "Alph"]

All slice operations return a new list containing the requested
elements.  This means that the following slice returns a *note shallow
copy: 1d97. of the list:

     >>> correct_rgba = rgba[:]
     >>> correct_rgba[-1] = "Alpha"
     >>> correct_rgba
     ["Red", "Green", "Blue", "Alpha"]
     >>> rgba
     ["Red", "Green", "Blue", "Alph"]

Assignment to slices is also possible, and this can even change the size
of the list or clear it entirely:

     >>> letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
     >>> letters
     ['a', 'b', 'c', 'd', 'e', 'f', 'g']
     >>> # replace some values
     >>> letters[2:5] = ['C', 'D', 'E']
     >>> letters
     ['a', 'b', 'C', 'D', 'E', 'f', 'g']
     >>> # now remove them
     >>> letters[2:5] = []
     >>> letters
     ['a', 'b', 'f', 'g']
     >>> # clear the list by replacing all the elements with an empty list
     >>> letters[:] = []
     >>> letters
     []

The built-in function *note len(): 631. also applies to lists:

     >>> letters = ['a', 'b', 'c', 'd']
     >>> len(letters)
     4

It is possible to nest lists (create lists containing other lists), for
example:

     >>> a = ['a', 'b', 'c']
     >>> n = [1, 2, 3]
     >>> x = [a, n]
     >>> x
     [['a', 'b', 'c'], [1, 2, 3]]
     >>> x[0]
     ['a', 'b', 'c']
     >>> x[0][1]
     'b'


File: python.info,  Node: First Steps Towards Programming,  Prev: Using Python as a Calculator,  Up: An Informal Introduction to Python

2.3.2 First Steps Towards Programming
-------------------------------------

Of course, we can use Python for more complicated tasks than adding two
and two together.  For instance, we can write an initial sub-sequence of
the Fibonacci series(1) as follows:

     >>> # Fibonacci series:
     >>> # the sum of two elements defines the next
     >>> a, b = 0, 1
     >>> while a < 10:
     ...     print(a)
     ...     a, b = b, a+b
     ...
     0
     1
     1
     2
     3
     5
     8

This example introduces several new features.

   * The first line contains a 'multiple assignment': the variables ‘a’
     and ‘b’ simultaneously get the new values 0 and 1.  On the last
     line this is used again, demonstrating that the expressions on the
     right-hand side are all evaluated first before any of the
     assignments take place.  The right-hand side expressions are
     evaluated from the left to the right.

   * The *note while: 1d9a. loop executes as long as the condition
     (here: ‘a < 10’) remains true.  In Python, like in C, any non-zero
     integer value is true; zero is false.  The condition may also be a
     string or list value, in fact any sequence; anything with a
     non-zero length is true, empty sequences are false.  The test used
     in the example is a simple comparison.  The standard comparison
     operators are written the same as in C: ‘<’ (less than), ‘>’
     (greater than), ‘==’ (equal to), ‘<=’ (less than or equal to), ‘>=’
     (greater than or equal to) and ‘!=’ (not equal to).

   * The 'body' of the loop is 'indented': indentation is Python’s way
     of grouping statements.  At the interactive prompt, you have to
     type a tab or space(s) for each indented line.  In practice you
     will prepare more complicated input for Python with a text editor;
     all decent text editors have an auto-indent facility.  When a
     compound statement is entered interactively, it must be followed by
     a blank line to indicate completion (since the parser cannot guess
     when you have typed the last line).  Note that each line within a
     basic block must be indented by the same amount.

   * The *note print(): fae. function writes the value of the
     argument(s) it is given.  It differs from just writing the
     expression you want to write (as we did earlier in the calculator
     examples) in the way it handles multiple arguments, floating-point
     quantities, and strings.  Strings are printed without quotes, and a
     space is inserted between items, so you can format things nicely,
     like this:

          >>> i = 256*256
          >>> print('The value of i is', i)
          The value of i is 65536

     The keyword argument 'end' can be used to avoid the newline after
     the output, or end the output with a different string:

          >>> a, b = 0, 1
          >>> while a < 1000:
          ...     print(a, end=',')
          ...     a, b = b, a+b
          ...
          0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Fibonacci_sequence


File: python.info,  Node: More Control Flow Tools,  Next: Data Structures,  Prev: An Informal Introduction to Python,  Up: The Python Tutorial

2.4 More Control Flow Tools
===========================

As well as the *note while: 1d9a. statement just introduced, Python uses
a few more that we will encounter in this chapter.

* Menu:

* if Statements::
* for Statements::
* The range() Function: The range Function.
* break and continue Statements::
* else Clauses on Loops::
* pass Statements::
* match Statements::
* Defining Functions::
* More on Defining Functions::
* Intermezzo; Coding Style: Intermezzo Coding Style.


File: python.info,  Node: if Statements,  Next: for Statements,  Up: More Control Flow Tools

2.4.1 ‘if’ Statements
---------------------

Perhaps the most well-known statement type is the *note if: 2f3.
statement.  For example:

     >>> x = int(input("Please enter an integer: "))
     Please enter an integer: 42
     >>> if x < 0:
     ...     x = 0
     ...     print('Negative changed to zero')
     ... elif x == 0:
     ...     print('Zero')
     ... elif x == 1:
     ...     print('Single')
     ... else:
     ...     print('More')
     ...
     More

There can be zero or more *note elif: 1da1. parts, and the *note else:
18c. part is optional.  The keyword ‘‘elif’’ is short for ‘else if’, and
is useful to avoid excessive indentation.  An ‘if’ … ‘elif’ … ‘elif’ …
sequence is a substitute for the ‘switch’ or ‘case’ statements found in
other languages.

If you’re comparing the same value to several constants, or checking for
specific types or attributes, you may also find the ‘match’ statement
useful.  For more details see *note match Statements: 1da2.


File: python.info,  Node: for Statements,  Next: The range Function,  Prev: if Statements,  Up: More Control Flow Tools

2.4.2 ‘for’ Statements
----------------------

The *note for: 2f2. statement in Python differs a bit from what you may
be used to in C or Pascal.  Rather than always iterating over an
arithmetic progression of numbers (like in Pascal), or giving the user
the ability to define both the iteration step and halting condition (as
C), Python’s ‘for’ statement iterates over the items of any sequence (a
list or a string), in the order that they appear in the sequence.  For
example (no pun intended):

     >>> # Measure some strings:
     >>> words = ['cat', 'window', 'defenestrate']
     >>> for w in words:
     ...     print(w, len(w))
     ...
     cat 3
     window 6
     defenestrate 12

Code that modifies a collection while iterating over that same
collection can be tricky to get right.  Instead, it is usually more
straight-forward to loop over a copy of the collection or to create a
new collection:

     # Create a sample collection
     users = {'Hans': 'active', 'Éléonore': 'inactive', '景太郎': 'active'}

     # Strategy:  Iterate over a copy
     for user, status in users.copy().items():
         if status == 'inactive':
             del users[user]

     # Strategy:  Create a new collection
     active_users = {}
     for user, status in users.items():
         if status == 'active':
             active_users[user] = status


File: python.info,  Node: The range Function,  Next: break and continue Statements,  Prev: for Statements,  Up: More Control Flow Tools

2.4.3 The ‘range()’ Function
----------------------------

If you do need to iterate over a sequence of numbers, the built-in
function *note range(): 94d. comes in handy.  It generates arithmetic
progressions:

     >>> for i in range(5):
     ...     print(i)
     ...
     0
     1
     2
     3
     4

The given end point is never part of the generated sequence; ‘range(10)’
generates 10 values, the legal indices for items of a sequence of length
10.  It is possible to let the range start at another number, or to
specify a different increment (even negative; sometimes this is called
the ‘step’):

     >>> list(range(5, 10))
     [5, 6, 7, 8, 9]

     >>> list(range(0, 10, 3))
     [0, 3, 6, 9]

     >>> list(range(-10, -100, -30))
     [-10, -40, -70]

To iterate over the indices of a sequence, you can combine *note
range(): 94d. and *note len(): 631. as follows:

     >>> a = ['Mary', 'had', 'a', 'little', 'lamb']
     >>> for i in range(len(a)):
     ...     print(i, a[i])
     ...
     0 Mary
     1 had
     2 a
     3 little
     4 lamb

In most such cases, however, it is convenient to use the *note
enumerate(): 14d0. function, see *note Looping Techniques: 1da7.

A strange thing happens if you just print a range:

     >>> range(10)
     range(0, 10)

In many ways the object returned by *note range(): 94d. behaves as if it
is a list, but in fact it isn’t.  It is an object which returns the
successive items of the desired sequence when you iterate over it, but
it doesn’t really make the list, thus saving space.

We say such an object is *note iterable: 126d, that is, suitable as a
target for functions and constructs that expect something from which
they can obtain successive items until the supply is exhausted.  We have
seen that the *note for: 2f2. statement is such a construct, while an
example of a function that takes an iterable is *note sum(): 46d.:

     >>> sum(range(4))  # 0 + 1 + 2 + 3
     6

Later we will see more functions that return iterables and take
iterables as arguments.  In chapter *note Data Structures: 1da8, we will
discuss *note list(): 614. in more detail.


File: python.info,  Node: break and continue Statements,  Next: else Clauses on Loops,  Prev: The range Function,  Up: More Control Flow Tools

2.4.4 ‘break’ and ‘continue’ Statements
---------------------------------------

The *note break: abe. statement breaks out of the innermost enclosing
*note for: 2f2. or *note while: 1d9a. loop:

     >>> for n in range(2, 10):
     ...     for x in range(2, n):
     ...         if n % x == 0:
     ...             print(f"{n} equals {x} * {n//x}")
     ...             break
     ...
     4 equals 2 * 2
     6 equals 2 * 3
     8 equals 2 * 4
     9 equals 3 * 3

The *note continue: 9d4. statement continues with the next iteration of
the loop:

     >>> for num in range(2, 10):
     ...     if num % 2 == 0:
     ...         print(f"Found an even number {num}")
     ...         continue
     ...     print(f"Found an odd number {num}")
     ...
     Found an even number 2
     Found an odd number 3
     Found an even number 4
     Found an odd number 5
     Found an even number 6
     Found an odd number 7
     Found an even number 8
     Found an odd number 9


File: python.info,  Node: else Clauses on Loops,  Next: pass Statements,  Prev: break and continue Statements,  Up: More Control Flow Tools

2.4.5 ‘else’ Clauses on Loops
-----------------------------

In a ‘for’ or ‘while’ loop the ‘break’ statement may be paired with an
‘else’ clause.  If the loop finishes without executing the ‘break’, the
‘else’ clause executes.

In a *note for: 2f2. loop, the ‘else’ clause is executed after the loop
finishes its final iteration, that is, if no break occurred.

In a *note while: 1d9a. loop, it’s executed after the loop’s condition
becomes false.

In either kind of loop, the ‘else’ clause is 'not' executed if the loop
was terminated by a *note break: abe.  Of course, other ways of ending
the loop early, such as a *note return: 9d9. or a raised exception, will
also skip execution of the *note else: 18c. clause.

This is exemplified in the following ‘for’ loop, which searches for
prime numbers:

     >>> for n in range(2, 10):
     ...     for x in range(2, n):
     ...         if n % x == 0:
     ...             print(n, 'equals', x, '*', n//x)
     ...             break
     ...     else:
     ...         # loop fell through without finding a factor
     ...         print(n, 'is a prime number')
     ...
     2 is a prime number
     3 is a prime number
     4 equals 2 * 2
     5 is a prime number
     6 equals 2 * 3
     7 is a prime number
     8 equals 2 * 4
     9 equals 3 * 3

(Yes, this is the correct code.  Look closely: the ‘else’ clause belongs
to the ‘for’ loop, 'not' the ‘if’ statement.)

One way to think of the else clause is to imagine it paired with the
‘if’ inside the loop.  As the loop executes, it will run a sequence like
if/if/if/else.  The ‘if’ is inside the loop, encountered a number of
times.  If the condition is ever true, a ‘break’ will happen.  If the
condition is never true, the ‘else’ clause outside the loop will
execute.

When used with a loop, the ‘else’ clause has more in common with the
‘else’ clause of a *note try: 6ec. statement than it does with that of
‘if’ statements: a ‘try’ statement’s ‘else’ clause runs when no
exception occurs, and a loop’s ‘else’ clause runs when no ‘break’
occurs.  For more on the ‘try’ statement and exceptions, see *note
Handling Exceptions: 1dae.


File: python.info,  Node: pass Statements,  Next: match Statements,  Prev: else Clauses on Loops,  Up: More Control Flow Tools

2.4.6 ‘pass’ Statements
-----------------------

The *note pass: 1db1. statement does nothing.  It can be used when a
statement is required syntactically but the program requires no action.
For example:

     >>> while True:
     ...     pass  # Busy-wait for keyboard interrupt (Ctrl+C)
     ...

This is commonly used for creating minimal classes:

     >>> class MyEmptyClass:
     ...     pass
     ...

Another place *note pass: 1db1. can be used is as a place-holder for a
function or conditional body when you are working on new code, allowing
you to keep thinking at a more abstract level.  The ‘pass’ is silently
ignored:

     >>> def initlog(*args):
     ...     pass   # Remember to implement this!
     ...

For this last case, many people use the ellipsis literal ‘...’ instead
of ‘pass’.  This use has no special meaning to Python, and is not part
of the language definition (you could use any constant expression here),
but ‘...’ is used conventionally as a placeholder body as well.  See
*note The Ellipsis Object: 1db2.


File: python.info,  Node: match Statements,  Next: Defining Functions,  Prev: pass Statements,  Up: More Control Flow Tools

2.4.7 ‘match’ Statements
------------------------

A *note match: 813. statement takes an expression and compares its value
to successive patterns given as one or more case blocks.  This is
superficially similar to a switch statement in C, Java or JavaScript
(and many other languages), but it’s more similar to pattern matching in
languages like Rust or Haskell.  Only the first pattern that matches
gets executed and it can also extract components (sequence elements or
object attributes) from the value into variables.

The simplest form compares a subject value against one or more literals:

     def http_error(status):
         match status:
             case 400:
                 return "Bad request"
             case 404:
                 return "Not found"
             case 418:
                 return "I'm a teapot"
             case _:
                 return "Something's wrong with the internet"

Note the last block: the “variable name” ‘_’ acts as a 'wildcard' and
never fails to match.  If no case matches, none of the branches is
executed.

You can combine several literals in a single pattern using ‘|’ (“or”):

     case 401 | 403 | 404:
         return "Not allowed"

Patterns can look like unpacking assignments, and can be used to bind
variables:

     # point is an (x, y) tuple
     match point:
         case (0, 0):
             print("Origin")
         case (0, y):
             print(f"Y={y}")
         case (x, 0):
             print(f"X={x}")
         case (x, y):
             print(f"X={x}, Y={y}")
         case _:
             raise ValueError("Not a point")

Study that one carefully!  The first pattern has two literals, and can
be thought of as an extension of the literal pattern shown above.  But
the next two patterns combine a literal and a variable, and the variable
'binds' a value from the subject (‘point’).  The fourth pattern captures
two values, which makes it conceptually similar to the unpacking
assignment ‘(x, y) = point’.

If you are using classes to structure your data you can use the class
name followed by an argument list resembling a constructor, but with the
ability to capture attributes into variables:

     class Point:
         def __init__(self, x, y):
             self.x = x
             self.y = y

     def where_is(point):
         match point:
             case Point(x=0, y=0):
                 print("Origin")
             case Point(x=0, y=y):
                 print(f"Y={y}")
             case Point(x=x, y=0):
                 print(f"X={x}")
             case Point():
                 print("Somewhere else")
             case _:
                 print("Not a point")

You can use positional parameters with some builtin classes that provide
an ordering for their attributes (e.g.  dataclasses).  You can also
define a specific position for attributes in patterns by setting the
‘__match_args__’ special attribute in your classes.  If it’s set to
(“x”, “y”), the following patterns are all equivalent (and all bind the
‘y’ attribute to the ‘var’ variable):

     Point(1, var)
     Point(1, y=var)
     Point(x=1, y=var)
     Point(y=var, x=1)

A recommended way to read patterns is to look at them as an extended
form of what you would put on the left of an assignment, to understand
which variables would be set to what.  Only the standalone names (like
‘var’ above) are assigned to by a match statement.  Dotted names (like
‘foo.bar’), attribute names (the ‘x=’ and ‘y=’ above) or class names
(recognized by the “(…)” next to them like ‘Point’ above) are never
assigned to.

Patterns can be arbitrarily nested.  For example, if we have a short
list of Points, with ‘__match_args__’ added, we could match it like
this:

     class Point:
         __match_args__ = ('x', 'y')
         def __init__(self, x, y):
             self.x = x
             self.y = y

     match points:
         case []:
             print("No points")
         case [Point(0, 0)]:
             print("The origin")
         case [Point(x, y)]:
             print(f"Single point {x}, {y}")
         case [Point(0, y1), Point(0, y2)]:
             print(f"Two on the Y axis at {y1}, {y2}")
         case _:
             print("Something else")

We can add an ‘if’ clause to a pattern, known as a “guard”.  If the
guard is false, ‘match’ goes on to try the next case block.  Note that
value capture happens before the guard is evaluated:

     match point:
         case Point(x, y) if x == y:
             print(f"Y=X at {x}")
         case Point(x, y):
             print(f"Not on the diagonal")

Several other key features of this statement:

   - Like unpacking assignments, tuple and list patterns have exactly
     the same meaning and actually match arbitrary sequences.  An
     important exception is that they don’t match iterators or strings.

   - Sequence patterns support extended unpacking: ‘[x, y, *rest]’ and
     ‘(x, y, *rest)’ work similar to unpacking assignments.  The name
     after ‘*’ may also be ‘_’, so ‘(x, y, *_)’ matches a sequence of at
     least two items without binding the remaining items.

   - Mapping patterns: ‘{"bandwidth": b, "latency": l}’ captures the
     ‘"bandwidth"’ and ‘"latency"’ values from a dictionary.  Unlike
     sequence patterns, extra keys are ignored.  An unpacking like
     ‘**rest’ is also supported.  (But ‘**_’ would be redundant, so it
     is not allowed.)

   - Subpatterns may be captured using the ‘as’ keyword:

          case (Point(x1, y1), Point(x2, y2) as p2): ...

     will capture the second element of the input as ‘p2’ (as long as
     the input is a sequence of two points)

   - Most literals are compared by equality, however the singletons
     ‘True’, ‘False’ and ‘None’ are compared by identity.

   - Patterns may use named constants.  These must be dotted names to
     prevent them from being interpreted as capture variables:

          from enum import Enum
          class Color(Enum):
              RED = 'red'
              GREEN = 'green'
              BLUE = 'blue'

          color = Color(input("Enter your choice of 'red', 'blue' or 'green': "))

          match color:
              case Color.RED:
                  print("I see red!")
              case Color.GREEN:
                  print("Grass is green")
              case Color.BLUE:
                  print("I'm feeling the blues :(")

For a more detailed explanation and additional examples, you can look
into PEP 636(1) which is written in a tutorial format.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0636/


File: python.info,  Node: Defining Functions,  Next: More on Defining Functions,  Prev: match Statements,  Up: More Control Flow Tools

2.4.8 Defining Functions
------------------------

We can create a function that writes the Fibonacci series to an
arbitrary boundary:

     >>> def fib(n):    # write Fibonacci series less than n
     ...     """Print a Fibonacci series less than n."""
     ...     a, b = 0, 1
     ...     while a < n:
     ...         print(a, end=' ')
     ...         a, b = b, a+b
     ...     print()
     ...
     >>> # Now call the function we just defined:
     >>> fib(2000)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

The keyword *note def: 14a9. introduces a function 'definition'.  It
must be followed by the function name and the parenthesized list of
formal parameters.  The statements that form the body of the function
start at the next line, and must be indented.

The first statement of the function body can optionally be a string
literal; this string literal is the function’s documentation string, or
'docstring'.  (More about docstrings can be found in the section *note
Documentation Strings: 1db6.)  There are tools which use docstrings to
automatically produce online or printed documentation, or to let the
user interactively browse through code; it’s good practice to include
docstrings in code that you write, so make a habit of it.

The 'execution' of a function introduces a new symbol table used for the
local variables of the function.  More precisely, all variable
assignments in a function store the value in the local symbol table;
whereas variable references first look in the local symbol table, then
in the local symbol tables of enclosing functions, then in the global
symbol table, and finally in the table of built-in names.  Thus, global
variables and variables of enclosing functions cannot be directly
assigned a value within a function (unless, for global variables, named
in a *note global: 18a. statement, or, for variables of enclosing
functions, named in a *note nonlocal: 12ef. statement), although they
may be referenced.

The actual parameters (arguments) to a function call are introduced in
the local symbol table of the called function when it is called; thus,
arguments are passed using 'call by value' (where the 'value' is always
an object 'reference', not the value of the object).  (1)  When a
function calls another function, or calls itself recursively, a new
local symbol table is created for that call.

A function definition associates the function name with the function
object in the current symbol table.  The interpreter recognizes the
object pointed to by that name as a user-defined function.  Other names
can also point to that same function object and can also be used to
access the function:

     >>> fib
     <function fib at 10042ed0>
     >>> f = fib
     >>> f(100)
     0 1 1 2 3 5 8 13 21 34 55 89

Coming from other languages, you might object that ‘fib’ is not a
function but a procedure since it doesn’t return a value.  In fact, even
functions without a *note return: 9d9. statement do return a value,
albeit a rather boring one.  This value is called ‘None’ (it’s a
built-in name).  Writing the value ‘None’ is normally suppressed by the
interpreter if it would be the only value written.  You can see it if
you really want to using *note print(): fae.:

     >>> fib(0)
     >>> print(fib(0))
     None

It is simple to write a function that returns a list of the numbers of
the Fibonacci series, instead of printing it:

     >>> def fib2(n):  # return Fibonacci series up to n
     ...     """Return a list containing the Fibonacci series up to n."""
     ...     result = []
     ...     a, b = 0, 1
     ...     while a < n:
     ...         result.append(a)    # see below
     ...         a, b = b, a+b
     ...     return result
     ...
     >>> f100 = fib2(100)    # call it
     >>> f100                # write the result
     [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

This example, as usual, demonstrates some new Python features:

   * The *note return: 9d9. statement returns with a value from a
     function.  ‘return’ without an expression argument returns ‘None’.
     Falling off the end of a function also returns ‘None’.

   * The statement ‘result.append(a)’ calls a 'method' of the list
     object ‘result’.  A method is a function that ‘belongs’ to an
     object and is named ‘obj.methodname’, where ‘obj’ is some object
     (this may be an expression), and ‘methodname’ is the name of a
     method that is defined by the object’s type.  Different types
     define different methods.  Methods of different types may have the
     same name without causing ambiguity.  (It is possible to define
     your own object types and methods, using 'classes', see *note
     Classes: 1db7.) The method *note append(): 6d0. shown in the
     example is defined for list objects; it adds a new element at the
     end of the list.  In this example it is equivalent to ‘result =
     result + [a]’, but more efficient.

   ---------- Footnotes ----------

   (1) Actually, 'call by object reference' would be a better
description, since if a mutable object is passed, the caller will see
any changes the callee makes to it (items inserted into a list).


File: python.info,  Node: More on Defining Functions,  Next: Intermezzo Coding Style,  Prev: Defining Functions,  Up: More Control Flow Tools

2.4.9 More on Defining Functions
--------------------------------

It is also possible to define functions with a variable number of
arguments.  There are three forms, which can be combined.

* Menu:

* Default Argument Values::
* Keyword Arguments::
* Special parameters::
* Arbitrary Argument Lists::
* Unpacking Argument Lists::
* Lambda Expressions::
* Documentation Strings::
* Function Annotations::


File: python.info,  Node: Default Argument Values,  Next: Keyword Arguments,  Up: More on Defining Functions

2.4.9.1 Default Argument Values
...............................

The most useful form is to specify a default value for one or more
arguments.  This creates a function that can be called with fewer
arguments than it is defined to allow.  For example:

     def ask_ok(prompt, retries=4, reminder='Please try again!'):
         while True:
             reply = input(prompt)
             if reply in {'y', 'ye', 'yes'}:
                 return True
             if reply in {'n', 'no', 'nop', 'nope'}:
                 return False
             retries = retries - 1
             if retries < 0:
                 raise ValueError('invalid user response')
             print(reminder)

This function can be called in several ways:

   * giving only the mandatory argument: ‘ask_ok('Do you really want to
     quit?')’

   * giving one of the optional arguments: ‘ask_ok('OK to overwrite the
     file?', 2)’

   * or even giving all arguments: ‘ask_ok('OK to overwrite the file?',
     2, 'Come on, only yes or no!')’

This example also introduces the *note in: 2f4. keyword.  This tests
whether or not a sequence contains a certain value.

The default values are evaluated at the point of function definition in
the 'defining' scope, so that

     i = 5

     def f(arg=i):
         print(arg)

     i = 6
     f()

will print ‘5’.

'Important warning:' The default value is evaluated only once.  This
makes a difference when the default is a mutable object such as a list,
dictionary, or instances of most classes.  For example, the following
function accumulates the arguments passed to it on subsequent calls:

     def f(a, L=[]):
         L.append(a)
         return L

     print(f(1))
     print(f(2))
     print(f(3))

This will print

     [1]
     [1, 2]
     [1, 2, 3]

If you don’t want the default to be shared between subsequent calls, you
can write the function like this instead:

     def f(a, L=None):
         if L is None:
             L = []
         L.append(a)
         return L


File: python.info,  Node: Keyword Arguments,  Next: Special parameters,  Prev: Default Argument Values,  Up: More on Defining Functions

2.4.9.2 Keyword Arguments
.........................

Functions can also be called using *note keyword arguments: d3a. of the
form ‘kwarg=value’.  For instance, the following function:

     def parrot(voltage, state='a stiff', action='voom', type='Norwegian Blue'):
         print("-- This parrot wouldn't", action, end=' ')
         print("if you put", voltage, "volts through it.")
         print("-- Lovely plumage, the", type)
         print("-- It's", state, "!")

accepts one required argument (‘voltage’) and three optional arguments
(‘state’, ‘action’, and ‘type’).  This function can be called in any of
the following ways:

     parrot(1000)                                          # 1 positional argument
     parrot(voltage=1000)                                  # 1 keyword argument
     parrot(voltage=1000000, action='VOOOOOM')             # 2 keyword arguments
     parrot(action='VOOOOOM', voltage=1000000)             # 2 keyword arguments
     parrot('a million', 'bereft of life', 'jump')         # 3 positional arguments
     parrot('a thousand', state='pushing up the daisies')  # 1 positional, 1 keyword

but all the following calls would be invalid:

     parrot()                     # required argument missing
     parrot(voltage=5.0, 'dead')  # non-keyword argument after a keyword argument
     parrot(110, voltage=220)     # duplicate value for the same argument
     parrot(actor='John Cleese')  # unknown keyword argument

In a function call, keyword arguments must follow positional arguments.
All the keyword arguments passed must match one of the arguments
accepted by the function (e.g.  ‘actor’ is not a valid argument for the
‘parrot’ function), and their order is not important.  This also
includes non-optional arguments (e.g.  ‘parrot(voltage=1000)’ is valid
too).  No argument may receive a value more than once.  Here’s an
example that fails due to this restriction:

     >>> def function(a):
     ...     pass
     ...
     >>> function(0, a=0)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: function() got multiple values for argument 'a'

When a final formal parameter of the form ‘**name’ is present, it
receives a dictionary (see *note Mapping Types — dict: adc.) containing
all keyword arguments except for those corresponding to a formal
parameter.  This may be combined with a formal parameter of the form
‘*name’ (described in the next subsection) which receives a *note tuple:
1dbe. containing the positional arguments beyond the formal parameter
list.  (‘*name’ must occur before ‘**name’.)  For example, if we define
a function like this:

     def cheeseshop(kind, *arguments, **keywords):
         print("-- Do you have any", kind, "?")
         print("-- I'm sorry, we're all out of", kind)
         for arg in arguments:
             print(arg)
         print("-" * 40)
         for kw in keywords:
             print(kw, ":", keywords[kw])

It could be called like this:

     cheeseshop("Limburger", "It's very runny, sir.",
                "It's really very, VERY runny, sir.",
                shopkeeper="Michael Palin",
                client="John Cleese",
                sketch="Cheese Shop Sketch")

and of course it would print:

     -- Do you have any Limburger ?
     -- I'm sorry, we're all out of Limburger
     It's very runny, sir.
     It's really very, VERY runny, sir.
     ----------------------------------------
     shopkeeper : Michael Palin
     client : John Cleese
     sketch : Cheese Shop Sketch

Note that the order in which the keyword arguments are printed is
guaranteed to match the order in which they were provided in the
function call.


File: python.info,  Node: Special parameters,  Next: Arbitrary Argument Lists,  Prev: Keyword Arguments,  Up: More on Defining Functions

2.4.9.3 Special parameters
..........................

By default, arguments may be passed to a Python function either by
position or explicitly by keyword.  For readability and performance, it
makes sense to restrict the way arguments can be passed so that a
developer need only look at the function definition to determine if
items are passed by position, by position or keyword, or by keyword.

A function definition may look like:

     def f(pos1, pos2, /, pos_or_kwd, *, kwd1, kwd2):
           -----------    ----------     ----------
             |             |                  |
             |        Positional or keyword   |
             |                                - Keyword only
              -- Positional only

where ‘/’ and ‘*’ are optional.  If used, these symbols indicate the
kind of parameter by how the arguments may be passed to the function:
positional-only, positional-or-keyword, and keyword-only.  Keyword
parameters are also referred to as named parameters.

* Menu:

* Positional-or-Keyword Arguments::
* Positional-Only Parameters::
* Keyword-Only Arguments::
* Function Examples::
* Recap::


File: python.info,  Node: Positional-or-Keyword Arguments,  Next: Positional-Only Parameters,  Up: Special parameters

2.4.9.4 Positional-or-Keyword Arguments
.......................................

If ‘/’ and ‘*’ are not present in the function definition, arguments may
be passed to a function by position or by keyword.


File: python.info,  Node: Positional-Only Parameters,  Next: Keyword-Only Arguments,  Prev: Positional-or-Keyword Arguments,  Up: Special parameters

2.4.9.5 Positional-Only Parameters
..................................

Looking at this in a bit more detail, it is possible to mark certain
parameters as 'positional-only'.  If 'positional-only', the parameters’
order matters, and the parameters cannot be passed by keyword.
Positional-only parameters are placed before a ‘/’ (forward-slash).  The
‘/’ is used to logically separate the positional-only parameters from
the rest of the parameters.  If there is no ‘/’ in the function
definition, there are no positional-only parameters.

Parameters following the ‘/’ may be 'positional-or-keyword' or
'keyword-only'.


File: python.info,  Node: Keyword-Only Arguments,  Next: Function Examples,  Prev: Positional-Only Parameters,  Up: Special parameters

2.4.9.6 Keyword-Only Arguments
..............................

To mark parameters as 'keyword-only', indicating the parameters must be
passed by keyword argument, place an ‘*’ in the arguments list just
before the first 'keyword-only' parameter.


File: python.info,  Node: Function Examples,  Next: Recap,  Prev: Keyword-Only Arguments,  Up: Special parameters

2.4.9.7 Function Examples
.........................

Consider the following example function definitions paying close
attention to the markers ‘/’ and ‘*’:

     >>> def standard_arg(arg):
     ...     print(arg)
     ...
     >>> def pos_only_arg(arg, /):
     ...     print(arg)
     ...
     >>> def kwd_only_arg(*, arg):
     ...     print(arg)
     ...
     >>> def combined_example(pos_only, /, standard, *, kwd_only):
     ...     print(pos_only, standard, kwd_only)

The first function definition, ‘standard_arg’, the most familiar form,
places no restrictions on the calling convention and arguments may be
passed by position or keyword:

     >>> standard_arg(2)
     2

     >>> standard_arg(arg=2)
     2

The second function ‘pos_only_arg’ is restricted to only use positional
parameters as there is a ‘/’ in the function definition:

     >>> pos_only_arg(1)
     1

     >>> pos_only_arg(arg=1)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: pos_only_arg() got some positional-only arguments passed as keyword arguments: 'arg'

The third function ‘kwd_only_arg’ only allows keyword arguments as
indicated by a ‘*’ in the function definition:

     >>> kwd_only_arg(3)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: kwd_only_arg() takes 0 positional arguments but 1 was given

     >>> kwd_only_arg(arg=3)
     3

And the last uses all three calling conventions in the same function
definition:

     >>> combined_example(1, 2, 3)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: combined_example() takes 2 positional arguments but 3 were given

     >>> combined_example(1, 2, kwd_only=3)
     1 2 3

     >>> combined_example(1, standard=2, kwd_only=3)
     1 2 3

     >>> combined_example(pos_only=1, standard=2, kwd_only=3)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: combined_example() got some positional-only arguments passed as keyword arguments: 'pos_only'

Finally, consider this function definition which has a potential
collision between the positional argument ‘name’ and ‘**kwds’ which has
‘name’ as a key:

     def foo(name, **kwds):
         return 'name' in kwds

There is no possible call that will make it return ‘True’ as the keyword
‘'name'’ will always bind to the first parameter.  For example:

     >>> foo(1, **{'name': 2})
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: foo() got multiple values for argument 'name'
     >>>

But using ‘/’ (positional only arguments), it is possible since it
allows ‘name’ as a positional argument and ‘'name'’ as a key in the
keyword arguments:

     >>> def foo(name, /, **kwds):
     ...     return 'name' in kwds
     ...
     >>> foo(1, **{'name': 2})
     True

In other words, the names of positional-only parameters can be used in
‘**kwds’ without ambiguity.


File: python.info,  Node: Recap,  Prev: Function Examples,  Up: Special parameters

2.4.9.8 Recap
.............

The use case will determine which parameters to use in the function
definition:

     def f(pos1, pos2, /, pos_or_kwd, *, kwd1, kwd2):

As guidance:

   * Use positional-only if you want the name of the parameters to not
     be available to the user.  This is useful when parameter names have
     no real meaning, if you want to enforce the order of the arguments
     when the function is called or if you need to take some positional
     parameters and arbitrary keywords.

   * Use keyword-only when names have meaning and the function
     definition is more understandable by being explicit with names or
     you want to prevent users relying on the position of the argument
     being passed.

   * For an API, use positional-only to prevent breaking API changes if
     the parameter’s name is modified in the future.


File: python.info,  Node: Arbitrary Argument Lists,  Next: Unpacking Argument Lists,  Prev: Special parameters,  Up: More on Defining Functions

2.4.9.9 Arbitrary Argument Lists
................................

Finally, the least frequently used option is to specify that a function
can be called with an arbitrary number of arguments.  These arguments
will be wrapped up in a tuple (see *note Tuples and Sequences: 1dbe.).
Before the variable number of arguments, zero or more normal arguments
may occur.

     def write_multiple_items(file, separator, *args):
         file.write(separator.join(args))

Normally, these 'variadic' arguments will be last in the list of formal
parameters, because they scoop up all remaining input arguments that are
passed to the function.  Any formal parameters which occur after the
‘*args’ parameter are ‘keyword-only’ arguments, meaning that they can
only be used as keywords rather than positional arguments.

     >>> def concat(*args, sep="/"):
     ...     return sep.join(args)
     ...
     >>> concat("earth", "mars", "venus")
     'earth/mars/venus'
     >>> concat("earth", "mars", "venus", sep=".")
     'earth.mars.venus'


File: python.info,  Node: Unpacking Argument Lists,  Next: Lambda Expressions,  Prev: Arbitrary Argument Lists,  Up: More on Defining Functions

2.4.9.10 Unpacking Argument Lists
.................................

The reverse situation occurs when the arguments are already in a list or
tuple but need to be unpacked for a function call requiring separate
positional arguments.  For instance, the built-in *note range(): 94d.
function expects separate 'start' and 'stop' arguments.  If they are not
available separately, write the function call with the ‘*’-operator to
unpack the arguments out of a list or tuple:

     >>> list(range(3, 6))            # normal call with separate arguments
     [3, 4, 5]
     >>> args = [3, 6]
     >>> list(range(*args))            # call with arguments unpacked from a list
     [3, 4, 5]

In the same fashion, dictionaries can deliver keyword arguments with the
‘**’-operator:

     >>> def parrot(voltage, state='a stiff', action='voom'):
     ...     print("-- This parrot wouldn't", action, end=' ')
     ...     print("if you put", voltage, "volts through it.", end=' ')
     ...     print("E's", state, "!")
     ...
     >>> d = {"voltage": "four million", "state": "bleedin' demised", "action": "VOOM"}
     >>> parrot(**d)
     -- This parrot wouldn't VOOM if you put four million volts through it. E's bleedin' demised !


File: python.info,  Node: Lambda Expressions,  Next: Documentation Strings,  Prev: Unpacking Argument Lists,  Up: More on Defining Functions

2.4.9.11 Lambda Expressions
...........................

Small anonymous functions can be created with the *note lambda: 12e4.
keyword.  This function returns the sum of its two arguments: ‘lambda a,
b: a+b’.  Lambda functions can be used wherever function objects are
required.  They are syntactically restricted to a single expression.
Semantically, they are just syntactic sugar for a normal function
definition.  Like nested function definitions, lambda functions can
reference variables from the containing scope:

     >>> def make_incrementor(n):
     ...     return lambda x: x + n
     ...
     >>> f = make_incrementor(42)
     >>> f(0)
     42
     >>> f(1)
     43

The above example uses a lambda expression to return a function.
Another use is to pass a small function as an argument.  For instance,
*note list.sort(): bee. takes a sorting key function 'key' which can be
a lambda function:

     >>> pairs = [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four')]
     >>> pairs.sort(key=lambda pair: pair[1])
     >>> pairs
     [(4, 'four'), (1, 'one'), (3, 'three'), (2, 'two')]


File: python.info,  Node: Documentation Strings,  Next: Function Annotations,  Prev: Lambda Expressions,  Up: More on Defining Functions

2.4.9.12 Documentation Strings
..............................

Here are some conventions about the content and formatting of
documentation strings.

The first line should always be a short, concise summary of the object’s
purpose.  For brevity, it should not explicitly state the object’s name
or type, since these are available by other means (except if the name
happens to be a verb describing a function’s operation).  This line
should begin with a capital letter and end with a period.

If there are more lines in the documentation string, the second line
should be blank, visually separating the summary from the rest of the
description.  The following lines should be one or more paragraphs
describing the object’s calling conventions, its side effects, etc.

The Python parser strips indentation from multi-line string literals
when they serve as module, class, or function docstrings.

Here is an example of a multi-line docstring:

     >>> def my_function():
     ...     """Do nothing, but document it.
     ...
     ...     No, really, it doesn't do anything:
     ...
     ...         >>> my_function()
     ...         >>>
     ...     """
     ...     pass
     ...
     >>> print(my_function.__doc__)
     Do nothing, but document it.

     No, really, it doesn't do anything:

         >>> my_function()
         >>>


File: python.info,  Node: Function Annotations,  Prev: Documentation Strings,  Up: More on Defining Functions

2.4.9.13 Function Annotations
.............................

*note Function annotations: 1dce. are completely optional metadata
information about the types used by user-defined functions (see PEP
3107(1) and PEP 484(2) for more information).

*note Annotations: 1dcf. are stored in the ‘__annotations__’ attribute
of the function as a dictionary and have no effect on any other part of
the function.  Parameter annotations are defined by a colon after the
parameter name, followed by an expression evaluating to the value of the
annotation.  Return annotations are defined by a literal ‘->’, followed
by an expression, between the parameter list and the colon denoting the
end of the *note def: 14a9. statement.  The following example has a
required argument, an optional argument, and the return value annotated:

     >>> def f(ham: str, eggs: str = 'eggs') -> str:
     ...     print("Annotations:", f.__annotations__)
     ...     print("Arguments:", ham, eggs)
     ...     return ham + ' and ' + eggs
     ...
     >>> f('spam')
     Annotations: {'ham': <class 'str'>, 'return': <class 'str'>, 'eggs': <class 'str'>}
     Arguments: spam eggs
     'spam and eggs'

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3107/

   (2) https://peps.python.org/pep-0484/


File: python.info,  Node: Intermezzo Coding Style,  Prev: More on Defining Functions,  Up: More Control Flow Tools

2.4.10 Intermezzo: Coding Style
-------------------------------

Now that you are about to write longer, more complex pieces of Python,
it is a good time to talk about 'coding style'.  Most languages can be
written (or more concisely, 'formatted') in different styles; some are
more readable than others.  Making it easy for others to read your code
is always a good idea, and adopting a nice coding style helps
tremendously for that.

For Python, PEP 8(1) has emerged as the style guide that most projects
adhere to; it promotes a very readable and eye-pleasing coding style.
Every Python developer should read it at some point; here are the most
important points extracted for you:

   * Use 4-space indentation, and no tabs.

     4 spaces are a good compromise between small indentation (allows
     greater nesting depth) and large indentation (easier to read).
     Tabs introduce confusion, and are best left out.

   * Wrap lines so that they don’t exceed 79 characters.

     This helps users with small displays and makes it possible to have
     several code files side-by-side on larger displays.

   * Use blank lines to separate functions and classes, and larger
     blocks of code inside functions.

   * When possible, put comments on a line of their own.

   * Use docstrings.

   * Use spaces around operators and after commas, but not directly
     inside bracketing constructs: ‘a = f(1, 2) + g(3, 4)’.

   * Name your classes and functions consistently; the convention is to
     use ‘UpperCamelCase’ for classes and ‘lowercase_with_underscores’
     for functions and methods.  Always use ‘self’ as the name for the
     first method argument (see *note A First Look at Classes: 1dd2. for
     more on classes and methods).

   * Don’t use fancy encodings if your code is meant to be used in
     international environments.  Python’s default, UTF-8, or even plain
     ASCII work best in any case.

   * Likewise, don’t use non-ASCII characters in identifiers if there is
     only the slightest chance people speaking a different language will
     read or maintain the code.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: Data Structures,  Next: Modules<2>,  Prev: More Control Flow Tools,  Up: The Python Tutorial

2.5 Data Structures
===================

This chapter describes some things you’ve learned about already in more
detail, and adds some new things as well.

* Menu:

* More on Lists::
* The del statement::
* Tuples and Sequences::
* Sets::
* Dictionaries::
* Looping Techniques::
* More on Conditions::
* Comparing Sequences and Other Types::


File: python.info,  Node: More on Lists,  Next: The del statement,  Up: Data Structures

2.5.1 More on Lists
-------------------

The *note list: 1dd8. data type has some more methods.  Here are all of
the methods of list objects:

 -- Method: list.append (value, /)

     Add an item to the end of the list.  Similar to ‘a[len(a):] = [x]’.

 -- Method: list.extend (iterable, /)

     Extend the list by appending all the items from the iterable.
     Similar to ‘a[len(a):] = iterable’.

 -- Method: list.insert (index, value, /)

     Insert an item at a given position.  The first argument is the
     index of the element before which to insert, so ‘a.insert(0, x)’
     inserts at the front of the list, and ‘a.insert(len(a), x)’ is
     equivalent to ‘a.append(x)’.

 -- Method: list.remove (value, /)

     Remove the first item from the list whose value is equal to
     'value'.  It raises a *note ValueError: 202. if there is no such
     item.

 -- Method: list.pop (index=-1, /)

     Remove the item at the given position in the list, and return it.
     If no index is specified, ‘a.pop()’ removes and returns the last
     item in the list.  It raises an *note IndexError: 1585. if the list
     is empty or the index is outside the list range.

 -- Method: list.clear ()

     Remove all items from the list.  Similar to ‘del a[:]’.

 -- Method: list.index (value[, start[, stop]])

     Return zero-based index of the first occurrence of 'value' in the
     list.  Raises a *note ValueError: 202. if there is no such item.

     The optional arguments 'start' and 'end' are interpreted as in the
     slice notation and are used to limit the search to a particular
     subsequence of the list.  The returned index is computed relative
     to the beginning of the full sequence rather than the 'start'
     argument.

 -- Method: list.count (value, /)

     Return the number of times 'value' appears in the list.

 -- Method: list.sort (*, key=None, reverse=False)

     Sort the items of the list in place (the arguments can be used for
     sort customization, see *note sorted(): bed. for their
     explanation).

 -- Method: list.reverse ()

     Reverse the elements of the list in place.

 -- Method: list.copy ()

     Return a shallow copy of the list.  Similar to ‘a[:]’.

An example that uses most of the list methods:

     >>> fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', 'banana']
     >>> fruits.count('apple')
     2
     >>> fruits.count('tangerine')
     0
     >>> fruits.index('banana')
     3
     >>> fruits.index('banana', 4)  # Find next banana starting at position 4
     6
     >>> fruits.reverse()
     >>> fruits
     ['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']
     >>> fruits.append('grape')
     >>> fruits
     ['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']
     >>> fruits.sort()
     >>> fruits
     ['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']
     >>> fruits.pop()
     'pear'

You might have noticed that methods like ‘insert’, ‘remove’ or ‘sort’
that only modify the list have no return value printed – they return the
default ‘None’.  (1)  This is a design principle for all mutable data
structures in Python.

Another thing you might notice is that not all data can be sorted or
compared.  For instance, ‘[None, 'hello', 10]’ doesn’t sort because
integers can’t be compared to strings and ‘None’ can’t be compared to
other types.  Also, there are some types that don’t have a defined
ordering relation.  For example, ‘3+4j < 5+7j’ isn’t a valid comparison.

* Menu:

* Using Lists as Stacks::
* Using Lists as Queues::
* List Comprehensions: List Comprehensions<2>.
* Nested List Comprehensions::

   ---------- Footnotes ----------

   (1) Other languages may return the mutated object, which allows
method chaining, such as ‘d->insert("a")->remove("b")->sort();’.


File: python.info,  Node: Using Lists as Stacks,  Next: Using Lists as Queues,  Up: More on Lists

2.5.1.1 Using Lists as Stacks
.............................

The list methods make it very easy to use a list as a stack, where the
last element added is the first element retrieved (“last-in,
first-out”).  To add an item to the top of the stack, use *note
append(): 6d0.  To retrieve an item from the top of the stack, use *note
pop(): 1ddb. without an explicit index.  For example:

     >>> stack = [3, 4, 5]
     >>> stack.append(6)
     >>> stack.append(7)
     >>> stack
     [3, 4, 5, 6, 7]
     >>> stack.pop()
     7
     >>> stack
     [3, 4, 5, 6]
     >>> stack.pop()
     6
     >>> stack.pop()
     5
     >>> stack
     [3, 4]


File: python.info,  Node: Using Lists as Queues,  Next: List Comprehensions<2>,  Prev: Using Lists as Stacks,  Up: More on Lists

2.5.1.2 Using Lists as Queues
.............................

It is also possible to use a list as a queue, where the first element
added is the first element retrieved (“first-in, first-out”); however,
lists are not efficient for this purpose.  While appends and pops from
the end of list are fast, doing inserts or pops from the beginning of a
list is slow (because all of the other elements have to be shifted by
one).

To implement a queue, use *note collections.deque: 5df. which was
designed to have fast appends and pops from both ends.  For example:

     >>> from collections import deque
     >>> queue = deque(["Eric", "John", "Michael"])
     >>> queue.append("Terry")           # Terry arrives
     >>> queue.append("Graham")          # Graham arrives
     >>> queue.popleft()                 # The first to arrive now leaves
     'Eric'
     >>> queue.popleft()                 # The second to arrive now leaves
     'John'
     >>> queue                           # Remaining queue in order of arrival
     deque(['Michael', 'Terry', 'Graham'])


File: python.info,  Node: List Comprehensions<2>,  Next: Nested List Comprehensions,  Prev: Using Lists as Queues,  Up: More on Lists

2.5.1.3 List Comprehensions
...........................

List comprehensions provide a concise way to create lists.  Common
applications are to make new lists where each element is the result of
some operations applied to each member of another sequence or iterable,
or to create a subsequence of those elements that satisfy a certain
condition.

For example, assume we want to create a list of squares, like:

     >>> squares = []
     >>> for x in range(10):
     ...     squares.append(x**2)
     ...
     >>> squares
     [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

Note that this creates (or overwrites) a variable named ‘x’ that still
exists after the loop completes.  We can calculate the list of squares
without any side effects using:

     squares = list(map(lambda x: x**2, range(10)))

or, equivalently:

     squares = [x**2 for x in range(10)]

which is more concise and readable.

A list comprehension consists of brackets containing an expression
followed by a ‘for’ clause, then zero or more ‘for’ or ‘if’ clauses.
The result will be a new list resulting from evaluating the expression
in the context of the ‘for’ and ‘if’ clauses which follow it.  For
example, this listcomp combines the elements of two lists if they are
not equal:

     >>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]
     [(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]

and it’s equivalent to:

     >>> combs = []
     >>> for x in [1,2,3]:
     ...     for y in [3,1,4]:
     ...         if x != y:
     ...             combs.append((x, y))
     ...
     >>> combs
     [(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]

Note how the order of the *note for: 2f2. and *note if: 2f3. statements
is the same in both these snippets.

If the expression is a tuple (e.g.  the ‘(x, y)’ in the previous
example), it must be parenthesized.

     >>> vec = [-4, -2, 0, 2, 4]
     >>> # create a new list with the values doubled
     >>> [x*2 for x in vec]
     [-8, -4, 0, 4, 8]
     >>> # filter the list to exclude negative numbers
     >>> [x for x in vec if x >= 0]
     [0, 2, 4]
     >>> # apply a function to all the elements
     >>> [abs(x) for x in vec]
     [4, 2, 0, 2, 4]
     >>> # call a method on each element
     >>> freshfruit = ['  banana', '  loganberry ', 'passion fruit  ']
     >>> [weapon.strip() for weapon in freshfruit]
     ['banana', 'loganberry', 'passion fruit']
     >>> # create a list of 2-tuples like (number, square)
     >>> [(x, x**2) for x in range(6)]
     [(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]
     >>> # the tuple must be parenthesized, otherwise an error is raised
     >>> [x, x**2 for x in range(6)]
       File "<stdin>", line 1
         [x, x**2 for x in range(6)]
          ^^^^^^^
     SyntaxError: did you forget parentheses around the comprehension target?
     >>> # flatten a list using a listcomp with two 'for'
     >>> vec = [[1,2,3], [4,5,6], [7,8,9]]
     >>> [num for elem in vec for num in elem]
     [1, 2, 3, 4, 5, 6, 7, 8, 9]

List comprehensions can contain complex expressions and nested
functions:

     >>> from math import pi
     >>> [str(round(pi, i)) for i in range(1, 6)]
     ['3.1', '3.14', '3.142', '3.1416', '3.14159']


File: python.info,  Node: Nested List Comprehensions,  Prev: List Comprehensions<2>,  Up: More on Lists

2.5.1.4 Nested List Comprehensions
..................................

The initial expression in a list comprehension can be any arbitrary
expression, including another list comprehension.

Consider the following example of a 3x4 matrix implemented as a list of
3 lists of length 4:

     >>> matrix = [
     ...     [1, 2, 3, 4],
     ...     [5, 6, 7, 8],
     ...     [9, 10, 11, 12],
     ... ]

The following list comprehension will transpose rows and columns:

     >>> [[row[i] for row in matrix] for i in range(4)]
     [[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

As we saw in the previous section, the inner list comprehension is
evaluated in the context of the *note for: 2f2. that follows it, so this
example is equivalent to:

     >>> transposed = []
     >>> for i in range(4):
     ...     transposed.append([row[i] for row in matrix])
     ...
     >>> transposed
     [[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

which, in turn, is the same as:

     >>> transposed = []
     >>> for i in range(4):
     ...     # the following 3 lines implement the nested listcomp
     ...     transposed_row = []
     ...     for row in matrix:
     ...         transposed_row.append(row[i])
     ...     transposed.append(transposed_row)
     ...
     >>> transposed
     [[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

In the real world, you should prefer built-in functions to complex flow
statements.  The *note zip(): 7d4. function would do a great job for
this use case:

     >>> list(zip(*matrix))
     [(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]

See *note Unpacking Argument Lists: 1dc7. for details on the asterisk in
this line.


File: python.info,  Node: The del statement,  Next: Tuples and Sequences,  Prev: More on Lists,  Up: Data Structures

2.5.2 The ‘del’ statement
-------------------------

There is a way to remove an item from a list given its index instead of
its value: the *note del: 18c2. statement.  This differs from the *note
pop(): 1ddb. method which returns a value.  The ‘del’ statement can also
be used to remove slices from a list or clear the entire list (which we
did earlier by assignment of an empty list to the slice).  For example:

     >>> a = [-1, 1, 66.25, 333, 333, 1234.5]
     >>> del a[0]
     >>> a
     [1, 66.25, 333, 333, 1234.5]
     >>> del a[2:4]
     >>> a
     [1, 66.25, 1234.5]
     >>> del a[:]
     >>> a
     []

*note del: 18c2. can also be used to delete entire variables:

     >>> del a

Referencing the name ‘a’ hereafter is an error (at least until another
value is assigned to it).  We’ll find other uses for *note del: 18c2.
later.


File: python.info,  Node: Tuples and Sequences,  Next: Sets,  Prev: The del statement,  Up: Data Structures

2.5.3 Tuples and Sequences
--------------------------

We saw that lists and strings have many common properties, such as
indexing and slicing operations.  They are two examples of 'sequence'
data types (see *note Sequence Types — list, tuple, range: 1de4.).
Since Python is an evolving language, other sequence data types may be
added.  There is also another standard sequence data type: the 'tuple'.

A tuple consists of a number of values separated by commas, for
instance:

     >>> t = 12345, 54321, 'hello!'
     >>> t[0]
     12345
     >>> t
     (12345, 54321, 'hello!')
     >>> # Tuples may be nested:
     >>> u = t, (1, 2, 3, 4, 5)
     >>> u
     ((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))
     >>> # Tuples are immutable:
     >>> t[0] = 88888
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: 'tuple' object does not support item assignment
     >>> # but they can contain mutable objects:
     >>> v = ([1, 2, 3], [3, 2, 1])
     >>> v
     ([1, 2, 3], [3, 2, 1])

As you see, on output tuples are always enclosed in parentheses, so that
nested tuples are interpreted correctly; they may be input with or
without surrounding parentheses, although often parentheses are
necessary anyway (if the tuple is part of a larger expression).  It is
not possible to assign to the individual items of a tuple, however it is
possible to create tuples which contain mutable objects, such as lists.

Though tuples may seem similar to lists, they are often used in
different situations and for different purposes.  Tuples are *note
immutable: 1d91, and usually contain a heterogeneous sequence of
elements that are accessed via unpacking (see later in this section) or
indexing (or even by attribute in the case of *note namedtuples: 1ca.).
Lists are *note mutable: 1d96, and their elements are usually
homogeneous and are accessed by iterating over the list.

A special problem is the construction of tuples containing 0 or 1 items:
the syntax has some extra quirks to accommodate these.  Empty tuples are
constructed by an empty pair of parentheses; a tuple with one item is
constructed by following a value with a comma (it is not sufficient to
enclose a single value in parentheses).  Ugly, but effective.  For
example:

     >>> empty = ()
     >>> singleton = 'hello',    # <-- note trailing comma
     >>> len(empty)
     0
     >>> len(singleton)
     1
     >>> singleton
     ('hello',)

The statement ‘t = 12345, 54321, 'hello!'’ is an example of 'tuple
packing': the values ‘12345’, ‘54321’ and ‘'hello!'’ are packed together
in a tuple.  The reverse operation is also possible:

     >>> x, y, z = t

This is called, appropriately enough, 'sequence unpacking' and works for
any sequence on the right-hand side.  Sequence unpacking requires that
there are as many variables on the left side of the equals sign as there
are elements in the sequence.  Note that multiple assignment is really
just a combination of tuple packing and sequence unpacking.


File: python.info,  Node: Sets,  Next: Dictionaries,  Prev: Tuples and Sequences,  Up: Data Structures

2.5.4 Sets
----------

Python also includes a data type for *note sets: 1de7.  A set is an
unordered collection with no duplicate elements.  Basic uses include
membership testing and eliminating duplicate entries.  Set objects also
support mathematical operations like union, intersection, difference,
and symmetric difference.

Curly braces or the *note set(): 5dc. function can be used to create
sets.  Note: to create an empty set you have to use ‘set()’, not ‘{}’;
the latter creates an empty dictionary, a data structure that we discuss
in the next section.

Because sets are unordered, iterating over them or printing them can
produce the elements in a different order than you expect.

Here is a brief demonstration:

     >>> basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
     >>> print(basket)                      # show that duplicates have been removed
     {'orange', 'banana', 'pear', 'apple'}
     >>> 'orange' in basket                 # fast membership testing
     True
     >>> 'crabgrass' in basket
     False

     >>> # Demonstrate set operations on unique letters from two words
     >>>
     >>> a = set('abracadabra')
     >>> b = set('alacazam')
     >>> a                                  # unique letters in a
     {'a', 'r', 'b', 'c', 'd'}
     >>> a - b                              # letters in a but not in b
     {'r', 'd', 'b'}
     >>> a | b                              # letters in a or b or both
     {'a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'}
     >>> a & b                              # letters in both a and b
     {'a', 'c'}
     >>> a ^ b                              # letters in a or b but not both
     {'r', 'd', 'b', 'm', 'z', 'l'}

Similarly to *note list comprehensions: 1ddf, set comprehensions are
also supported:

     >>> a = {x for x in 'abracadabra' if x not in 'abc'}
     >>> a
     {'r', 'd'}


File: python.info,  Node: Dictionaries,  Next: Looping Techniques,  Prev: Sets,  Up: Data Structures

2.5.5 Dictionaries
------------------

Another useful data type built into Python is the 'dictionary' (see
*note Mapping Types — dict: adc.).  Dictionaries are sometimes found in
other languages as “associative memories” or “associative arrays”.
Unlike sequences, which are indexed by a range of numbers, dictionaries
are indexed by 'keys', which can be any immutable type; strings and
numbers can always be keys.  Tuples can be used as keys if they contain
only strings, numbers, or tuples; if a tuple contains any mutable object
either directly or indirectly, it cannot be used as a key.  You can’t
use lists as keys, since lists can be modified in place using index
assignments, slice assignments, or methods like *note append(): 6d0. and
*note extend(): 360.

It is best to think of a dictionary as a set of 'key: value' pairs, with
the requirement that the keys are unique (within one dictionary).  A
pair of braces creates an empty dictionary: ‘{}’.  Placing a
comma-separated list of key:value pairs within the braces adds initial
key:value pairs to the dictionary; this is also the way dictionaries are
written on output.

The main operations on a dictionary are storing a value with some key
and extracting the value given the key.  It is also possible to delete a
key:value pair with ‘del’.  If you store using a key that is already in
use, the old value associated with that key is forgotten.

Extracting a value for a non-existent key by subscripting (‘d[key]’)
raises a *note KeyError: 345.  To avoid getting this error when trying
to access a possibly non-existent key, use the *note get(): 1dea. method
instead, which returns ‘None’ (or a specified default value) if the key
is not in the dictionary.

Performing ‘list(d)’ on a dictionary returns a list of all the keys used
in the dictionary, in insertion order (if you want it sorted, just use
‘sorted(d)’ instead).  To check whether a single key is in the
dictionary, use the *note in: 2f4. keyword.

Here is a small example using a dictionary:

     >>> tel = {'jack': 4098, 'sape': 4139}
     >>> tel['guido'] = 4127
     >>> tel
     {'jack': 4098, 'sape': 4139, 'guido': 4127}
     >>> tel['jack']
     4098
     >>> tel['irv']
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     KeyError: 'irv'
     >>> print(tel.get('irv'))
     None
     >>> del tel['sape']
     >>> tel['irv'] = 4127
     >>> tel
     {'jack': 4098, 'guido': 4127, 'irv': 4127}
     >>> list(tel)
     ['jack', 'guido', 'irv']
     >>> sorted(tel)
     ['guido', 'irv', 'jack']
     >>> 'guido' in tel
     True
     >>> 'jack' not in tel
     False

The *note dict(): 256. constructor builds dictionaries directly from
sequences of key-value pairs:

     >>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])
     {'sape': 4139, 'guido': 4127, 'jack': 4098}

In addition, dict comprehensions can be used to create dictionaries from
arbitrary key and value expressions:

     >>> {x: x**2 for x in (2, 4, 6)}
     {2: 4, 4: 16, 6: 36}

When the keys are simple strings, it is sometimes easier to specify
pairs using keyword arguments:

     >>> dict(sape=4139, guido=4127, jack=4098)
     {'sape': 4139, 'guido': 4127, 'jack': 4098}


File: python.info,  Node: Looping Techniques,  Next: More on Conditions,  Prev: Dictionaries,  Up: Data Structures

2.5.6 Looping Techniques
------------------------

When looping through dictionaries, the key and corresponding value can
be retrieved at the same time using the *note items(): 7d3. method.

     >>> knights = {'gallahad': 'the pure', 'robin': 'the brave'}
     >>> for k, v in knights.items():
     ...     print(k, v)
     ...
     gallahad the pure
     robin the brave

When looping through a sequence, the position index and corresponding
value can be retrieved at the same time using the *note enumerate():
14d0. function.

     >>> for i, v in enumerate(['tic', 'tac', 'toe']):
     ...     print(i, v)
     ...
     0 tic
     1 tac
     2 toe

To loop over two or more sequences at the same time, the entries can be
paired with the *note zip(): 7d4. function.

     >>> questions = ['name', 'quest', 'favorite color']
     >>> answers = ['lancelot', 'the holy grail', 'blue']
     >>> for q, a in zip(questions, answers):
     ...     print('What is your {0}?  It is {1}.'.format(q, a))
     ...
     What is your name?  It is lancelot.
     What is your quest?  It is the holy grail.
     What is your favorite color?  It is blue.

To loop over a sequence in reverse, first specify the sequence in a
forward direction and then call the *note reversed(): 86c. function.

     >>> for i in reversed(range(1, 10, 2)):
     ...     print(i)
     ...
     9
     7
     5
     3
     1

To loop over a sequence in sorted order, use the *note sorted(): bed.
function which returns a new sorted list while leaving the source
unaltered.

     >>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']
     >>> for i in sorted(basket):
     ...     print(i)
     ...
     apple
     apple
     banana
     orange
     orange
     pear

Using *note set(): 5dc. on a sequence eliminates duplicate elements.
The use of *note sorted(): bed. in combination with ‘set()’ over a
sequence is an idiomatic way to loop over unique elements of the
sequence in sorted order.

     >>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']
     >>> for f in sorted(set(basket)):
     ...     print(f)
     ...
     apple
     banana
     orange
     pear

It is sometimes tempting to change a list while you are looping over it;
however, it is often simpler and safer to create a new list instead.

     >>> import math
     >>> raw_data = [56.2, float('NaN'), 51.7, 55.3, 52.5, float('NaN'), 47.8]
     >>> filtered_data = []
     >>> for value in raw_data:
     ...     if not math.isnan(value):
     ...         filtered_data.append(value)
     ...
     >>> filtered_data
     [56.2, 51.7, 55.3, 52.5, 47.8]


File: python.info,  Node: More on Conditions,  Next: Comparing Sequences and Other Types,  Prev: Looping Techniques,  Up: Data Structures

2.5.7 More on Conditions
------------------------

The conditions used in ‘while’ and ‘if’ statements can contain any
operators, not just comparisons.

The comparison operators ‘in’ and ‘not in’ are membership tests that
determine whether a value is in (or not in) a container.  The operators
‘is’ and ‘is not’ compare whether two objects are really the same
object.  All comparison operators have the same priority, which is lower
than that of all numerical operators.

Comparisons can be chained.  For example, ‘a < b == c’ tests whether ‘a’
is less than ‘b’ and moreover ‘b’ equals ‘c’.

Comparisons may be combined using the Boolean operators ‘and’ and ‘or’,
and the outcome of a comparison (or of any other Boolean expression) may
be negated with ‘not’.  These have lower priorities than comparison
operators; between them, ‘not’ has the highest priority and ‘or’ the
lowest, so that ‘A and not B or C’ is equivalent to ‘(A and (not B)) or
C’.  As always, parentheses can be used to express the desired
composition.

The Boolean operators ‘and’ and ‘or’ are so-called 'short-circuit'
operators: their arguments are evaluated from left to right, and
evaluation stops as soon as the outcome is determined.  For example, if
‘A’ and ‘C’ are true but ‘B’ is false, ‘A and B and C’ does not evaluate
the expression ‘C’.  When used as a general value and not as a Boolean,
the return value of a short-circuit operator is the last evaluated
argument.

It is possible to assign the result of a comparison or other Boolean
expression to a variable.  For example,

     >>> string1, string2, string3 = '', 'Trondheim', 'Hammer Dance'
     >>> non_null = string1 or string2 or string3
     >>> non_null
     'Trondheim'

Note that in Python, unlike C, assignment inside expressions must be
done explicitly with the *note walrus operator: 1dee. ‘:=’.  This avoids
a common class of problems encountered in C programs: typing ‘=’ in an
expression when ‘==’ was intended.


File: python.info,  Node: Comparing Sequences and Other Types,  Prev: More on Conditions,  Up: Data Structures

2.5.8 Comparing Sequences and Other Types
-----------------------------------------

Sequence objects typically may be compared to other objects with the
same sequence type.  The comparison uses 'lexicographical' ordering:
first the first two items are compared, and if they differ this
determines the outcome of the comparison; if they are equal, the next
two items are compared, and so on, until either sequence is exhausted.
If two items to be compared are themselves sequences of the same type,
the lexicographical comparison is carried out recursively.  If all items
of two sequences compare equal, the sequences are considered equal.  If
one sequence is an initial sub-sequence of the other, the shorter
sequence is the smaller (lesser) one.  Lexicographical ordering for
strings uses the Unicode code point number to order individual
characters.  Some examples of comparisons between sequences of the same
type:

     (1, 2, 3)              < (1, 2, 4)
     [1, 2, 3]              < [1, 2, 4]
     'ABC' < 'C' < 'Pascal' < 'Python'
     (1, 2, 3, 4)           < (1, 2, 4)
     (1, 2)                 < (1, 2, -1)
     (1, 2, 3)             == (1.0, 2.0, 3.0)
     (1, 2, ('aa', 'ab'))   < (1, 2, ('abc', 'a'), 4)

Note that comparing objects of different types with ‘<’ or ‘>’ is legal
provided that the objects have appropriate comparison methods.  For
example, mixed numeric types are compared according to their numeric
value, so 0 equals 0.0, etc.  Otherwise, rather than providing an
arbitrary ordering, the interpreter will raise a *note TypeError: 2c3.
exception.


File: python.info,  Node: Modules<2>,  Next: Input and Output,  Prev: Data Structures,  Up: The Python Tutorial

2.6 Modules
===========

If you quit from the Python interpreter and enter it again, the
definitions you have made (functions and variables) are lost.
Therefore, if you want to write a somewhat longer program, you are
better off using a text editor to prepare the input for the interpreter
and running it with that file as input instead.  This is known as
creating a 'script'.  As your program gets longer, you may want to split
it into several files for easier maintenance.  You may also want to use
a handy function that you’ve written in several programs without copying
its definition into each program.

To support this, Python has a way to put definitions in a file and use
them in a script or in an interactive instance of the interpreter.  Such
a file is called a 'module'; definitions from a module can be 'imported'
into other modules or into the 'main' module (the collection of
variables that you have access to in a script executed at the top level
and in calculator mode).

A module is a file containing Python definitions and statements.  The
file name is the module name with the suffix ‘.py’ appended.  Within a
module, the module’s name (as a string) is available as the value of the
global variable ‘__name__’.  For instance, use your favorite text editor
to create a file called ‘fibo.py’ in the current directory with the
following contents:

     # Fibonacci numbers module

     def fib(n):
         """Write Fibonacci series up to n."""
         a, b = 0, 1
         while a < n:
             print(a, end=' ')
             a, b = b, a+b
         print()

     def fib2(n):
         """Return Fibonacci series up to n."""
         result = []
         a, b = 0, 1
         while a < n:
             result.append(a)
             a, b = b, a+b
         return result

Now enter the Python interpreter and import this module with the
following command:

     >>> import fibo

This does not add the names of the functions defined in ‘fibo’ directly
to the current *note namespace: 1df5. (see *note Python Scopes and
Namespaces: 1df6. for more details); it only adds the module name ‘fibo’
there.  Using the module name you can access the functions:

     >>> fibo.fib(1000)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987
     >>> fibo.fib2(100)
     [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
     >>> fibo.__name__
     'fibo'

If you intend to use a function often you can assign it to a local name:

     >>> fib = fibo.fib
     >>> fib(500)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

* Menu:

* More on Modules::
* Standard Modules::
* The dir() Function: The dir Function.
* Packages::


File: python.info,  Node: More on Modules,  Next: Standard Modules,  Up: Modules<2>

2.6.1 More on Modules
---------------------

A module can contain executable statements as well as function
definitions.  These statements are intended to initialize the module.
They are executed only the 'first' time the module name is encountered
in an import statement.  (1)  (They are also run if the file is executed
as a script.)

Each module has its own private namespace, which is used as the global
namespace by all functions defined in the module.  Thus, the author of a
module can use global variables in the module without worrying about
accidental clashes with a user’s global variables.  On the other hand,
if you know what you are doing you can touch a module’s global variables
with the same notation used to refer to its functions,
‘modname.itemname’.

Modules can import other modules.  It is customary but not required to
place all *note import: 5e5. statements at the beginning of a module (or
script, for that matter).  The imported module names, if placed at the
top level of a module (outside any functions or classes), are added to
the module’s global namespace.

There is a variant of the *note import: 5e5. statement that imports
names from a module directly into the importing module’s namespace.  For
example:

     >>> from fibo import fib, fib2
     >>> fib(500)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

This does not introduce the module name from which the imports are taken
in the local namespace (so in the example, ‘fibo’ is not defined).

There is even a variant to import all names that a module defines:

     >>> from fibo import *
     >>> fib(500)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

This imports all names except those beginning with an underscore (‘_’).
In most cases Python programmers do not use this facility since it
introduces an unknown set of names into the interpreter, possibly hiding
some things you have already defined.

Note that in general the practice of importing ‘*’ from a module or
package is frowned upon, since it often causes poorly readable code.
However, it is okay to use it to save typing in interactive sessions.

If the module name is followed by ‘as’, then the name following ‘as’ is
bound directly to the imported module.

     >>> import fibo as fib
     >>> fib.fib(500)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

This is effectively importing the module in the same way that ‘import
fibo’ will do, with the only difference of it being available as ‘fib’.

It can also be used when utilising *note from: 12f3. with similar
effects:

     >>> from fibo import fib as fibonacci
     >>> fibonacci(500)
     0 1 1 2 3 5 8 13 21 34 55 89 144 233 377

     Note: For efficiency reasons, each module is only imported once per
     interpreter session.  Therefore, if you change your modules, you
     must restart the interpreter – or, if it’s just one module you want
     to test interactively, use *note importlib.reload(): 51c, e.g.
     ‘import importlib; importlib.reload(modulename)’.

* Menu:

* Executing modules as scripts::
* The Module Search Path::
* “Compiled” Python files::

   ---------- Footnotes ----------

   (1) In fact function definitions are also ‘statements’ that are
‘executed’; the execution of a module-level function definition adds the
function name to the module’s global namespace.


File: python.info,  Node: Executing modules as scripts,  Next: The Module Search Path,  Up: More on Modules

2.6.1.1 Executing modules as scripts
....................................

When you run a Python module with

     python fibo.py <arguments>

the code in the module will be executed, just as if you imported it, but
with the ‘__name__’ set to ‘"__main__"’.  That means that by adding this
code at the end of your module:

     if __name__ == "__main__":
         import sys
         fib(int(sys.argv[1]))

you can make the file usable as a script as well as an importable
module, because the code that parses the command line only runs if the
module is executed as the “main” file:

     $ python fibo.py 50
     0 1 1 2 3 5 8 13 21 34

If the module is imported, the code is not run:

     >>> import fibo
     >>>

This is often used either to provide a convenient user interface to a
module, or for testing purposes (running the module as a script executes
a test suite).


File: python.info,  Node: The Module Search Path,  Next: “Compiled” Python files,  Prev: Executing modules as scripts,  Up: More on Modules

2.6.1.2 The Module Search Path
..............................

When a module named ‘spam’ is imported, the interpreter first searches
for a built-in module with that name.  These module names are listed in
*note sys.builtin_module_names: 1dfd.  If not found, it then searches
for a file named ‘spam.py’ in a list of directories given by the
variable *note sys.path: 3b7.  ‘sys.path’ is initialized from these
locations:

   * The directory containing the input script (or the current directory
     when no file is specified).

   * *note PYTHONPATH: 1058. (a list of directory names, with the same
     syntax as the shell variable ‘PATH’).

   * The installation-dependent default (by convention including a
     ‘site-packages’ directory, handled by the *note site: c7. module).

More details are at *note The initialization of the sys.path module
search path: 1dfe.

     Note: On file systems which support symlinks, the directory
     containing the input script is calculated after the symlink is
     followed.  In other words the directory containing the symlink is
     'not' added to the module search path.

After initialization, Python programs can modify *note sys.path: 3b7.
The directory containing the script being run is placed at the beginning
of the search path, ahead of the standard library path.  This means that
scripts in that directory will be loaded instead of modules of the same
name in the library directory.  This is an error unless the replacement
is intended.  See section *note Standard Modules: 1dff. for more
information.


File: python.info,  Node: “Compiled” Python files,  Prev: The Module Search Path,  Up: More on Modules

2.6.1.3 “Compiled” Python files
...............................

To speed up loading modules, Python caches the compiled version of each
module in the ‘__pycache__’ directory under the name
‘module.`version'.pyc’, where the version encodes the format of the
compiled file; it generally contains the Python version number.  For
example, in CPython release 3.3 the compiled version of spam.py would be
cached as ‘__pycache__/spam.cpython-33.pyc’.  This naming convention
allows compiled modules from different releases and different versions
of Python to coexist.

Python checks the modification date of the source against the compiled
version to see if it’s out of date and needs to be recompiled.  This is
a completely automatic process.  Also, the compiled modules are
platform-independent, so the same library can be shared among systems
with different architectures.

Python does not check the cache in two circumstances.  First, it always
recompiles and does not store the result for the module that’s loaded
directly from the command line.  Second, it does not check the cache if
there is no source module.  To support a non-source (compiled only)
distribution, the compiled module must be in the source directory, and
there must not be a source module.

Some tips for experts:

   * You can use the *note -O: de3. or *note -OO: de4. switches on the
     Python command to reduce the size of a compiled module.  The ‘-O’
     switch removes assert statements, the ‘-OO’ switch removes both
     assert statements and __doc__ strings.  Since some programs may
     rely on having these available, you should only use this option if
     you know what you’re doing.  “Optimized” modules have an ‘opt-’ tag
     and are usually smaller.  Future releases may change the effects of
     optimization.

   * A program doesn’t run any faster when it is read from a ‘.pyc’ file
     than when it is read from a ‘.py’ file; the only thing that’s
     faster about ‘.pyc’ files is the speed with which they are loaded.

   * The module *note compileall: 20. can create .pyc files for all
     modules in a directory.

   * There is more detail on this process, including a flow chart of the
     decisions, in PEP 3147(1).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: Standard Modules,  Next: The dir Function,  Prev: More on Modules,  Up: Modules<2>

2.6.2 Standard Modules
----------------------

Python comes with a library of standard modules, described in a separate
document, the Python Library Reference (“Library Reference” hereafter).
Some modules are built into the interpreter; these provide access to
operations that are not part of the core of the language but are
nevertheless built in, either for efficiency or to provide access to
operating system primitives such as system calls.  The set of such
modules is a configuration option which also depends on the underlying
platform.  For example, the *note winreg: 116. module is only provided
on Windows systems.  One particular module deserves some attention:
*note sys: d9, which is built into every Python interpreter.  The
variables ‘sys.ps1’ and ‘sys.ps2’ define the strings used as primary and
secondary prompts:

     >>> import sys
     >>> sys.ps1
     '>>> '
     >>> sys.ps2
     '... '
     >>> sys.ps1 = 'C> '
     C> print('Yuck!')
     Yuck!
     C>

These two variables are only defined if the interpreter is in
interactive mode.

The variable ‘sys.path’ is a list of strings that determines the
interpreter’s search path for modules.  It is initialized to a default
path taken from the environment variable *note PYTHONPATH: 1058, or from
a built-in default if ‘PYTHONPATH’ is not set.  You can modify it using
standard list operations:

     >>> import sys
     >>> sys.path.append('/ufs/guido/lib/python')


File: python.info,  Node: The dir Function,  Next: Packages,  Prev: Standard Modules,  Up: Modules<2>

2.6.3 The ‘dir()’ Function
--------------------------

The built-in function *note dir(): 635. is used to find out which names
a module defines.  It returns a sorted list of strings:

     >>> import fibo, sys
     >>> dir(fibo)
     ['__name__', 'fib', 'fib2']
     >>> dir(sys)
     ['__breakpointhook__', '__displayhook__', '__doc__', '__excepthook__',
      '__interactivehook__', '__loader__', '__name__', '__package__', '__spec__',
      '__stderr__', '__stdin__', '__stdout__', '__unraisablehook__',
      '_clear_type_cache', '_current_frames', '_debugmallocstats', '_framework',
      '_getframe', '_git', '_home', '_xoptions', 'abiflags', 'addaudithook',
      'api_version', 'argv', 'audit', 'base_exec_prefix', 'base_prefix',
      'breakpointhook', 'builtin_module_names', 'byteorder', 'call_tracing',
      'callstats', 'copyright', 'displayhook', 'dont_write_bytecode', 'exc_info',
      'excepthook', 'exec_prefix', 'executable', 'exit', 'flags', 'float_info',
      'float_repr_style', 'get_asyncgen_hooks', 'get_coroutine_origin_tracking_depth',
      'getallocatedblocks', 'getdefaultencoding', 'getdlopenflags',
      'getfilesystemencodeerrors', 'getfilesystemencoding', 'getprofile',
      'getrecursionlimit', 'getrefcount', 'getsizeof', 'getswitchinterval',
      'gettrace', 'hash_info', 'hexversion', 'implementation', 'int_info',
      'intern', 'is_finalizing', 'last_traceback', 'last_type', 'last_value',
      'maxsize', 'maxunicode', 'meta_path', 'modules', 'path', 'path_hooks',
      'path_importer_cache', 'platform', 'prefix', 'ps1', 'ps2', 'pycache_prefix',
      'set_asyncgen_hooks', 'set_coroutine_origin_tracking_depth', 'setdlopenflags',
      'setprofile', 'setrecursionlimit', 'setswitchinterval', 'settrace', 'stderr',
      'stdin', 'stdout', 'thread_info', 'unraisablehook', 'version', 'version_info',
      'warnoptions']

Without arguments, *note dir(): 635. lists the names you have defined
currently:

     >>> a = [1, 2, 3, 4, 5]
     >>> import fibo
     >>> fib = fibo.fib
     >>> dir()
     ['__builtins__', '__name__', 'a', 'fib', 'fibo', 'sys']

Note that it lists all types of names: variables, modules, functions,
etc.

*note dir(): 635. does not list the names of built-in functions and
variables.  If you want a list of those, they are defined in the
standard module *note builtins: 12.:

     >>> import builtins
     >>> dir(builtins)
     ['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException',
      'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning',
      'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError',
      'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning',
      'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False',
      'FileExistsError', 'FileNotFoundError', 'FloatingPointError',
      'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError',
      'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError',
      'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError',
      'MemoryError', 'NameError', 'None', 'NotADirectoryError', 'NotImplemented',
      'NotImplementedError', 'OSError', 'OverflowError',
      'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError',
      'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning',
      'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError',
      'SystemExit', 'TabError', 'TimeoutError', 'True', 'TypeError',
      'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError',
      'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning',
      'ValueError', 'Warning', 'ZeroDivisionError', '_', '__build_class__',
      '__debug__', '__doc__', '__import__', '__name__', '__package__', 'abs',
      'all', 'any', 'ascii', 'bin', 'bool', 'bytearray', 'bytes', 'callable',
      'chr', 'classmethod', 'compile', 'complex', 'copyright', 'credits',
      'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'exec', 'exit',
      'filter', 'float', 'format', 'frozenset', 'getattr', 'globals', 'hasattr',
      'hash', 'help', 'hex', 'id', 'input', 'int', 'isinstance', 'issubclass',
      'iter', 'len', 'license', 'list', 'locals', 'map', 'max', 'memoryview',
      'min', 'next', 'object', 'oct', 'open', 'ord', 'pow', 'print', 'property',
      'quit', 'range', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice',
      'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'vars',
      'zip']


File: python.info,  Node: Packages,  Prev: The dir Function,  Up: Modules<2>

2.6.4 Packages
--------------

Packages are a way of structuring Python’s module namespace by using
“dotted module names”.  For example, the module name ‘A.B’ designates a
submodule named ‘B’ in a package named ‘A’.  Just like the use of
modules saves the authors of different modules from having to worry
about each other’s global variable names, the use of dotted module names
saves the authors of multi-module packages like NumPy or Pillow from
having to worry about each other’s module names.

Suppose you want to design a collection of modules (a “package”) for the
uniform handling of sound files and sound data.  There are many
different sound file formats (usually recognized by their extension, for
example: ‘.wav’, ‘.aiff’, ‘.au’), so you may need to create and maintain
a growing collection of modules for the conversion between the various
file formats.  There are also many different operations you might want
to perform on sound data (such as mixing, adding echo, applying an
equalizer function, creating an artificial stereo effect), so in
addition you will be writing a never-ending stream of modules to perform
these operations.  Here’s a possible structure for your package
(expressed in terms of a hierarchical filesystem):

     sound/                          Top-level package
           __init__.py               Initialize the sound package
           formats/                  Subpackage for file format conversions
                   __init__.py
                   wavread.py
                   wavwrite.py
                   aiffread.py
                   aiffwrite.py
                   auread.py
                   auwrite.py
                   ...
           effects/                  Subpackage for sound effects
                   __init__.py
                   echo.py
                   surround.py
                   reverse.py
                   ...
           filters/                  Subpackage for filters
                   __init__.py
                   equalizer.py
                   vocoder.py
                   karaoke.py
                   ...

When importing the package, Python searches through the directories on
‘sys.path’ looking for the package subdirectory.

The ‘__init__.py’ files are required to make Python treat directories
containing the file as packages (unless using a *note namespace package:
1e06, a relatively advanced feature).  This prevents directories with a
common name, such as ‘string’, from unintentionally hiding valid modules
that occur later on the module search path.  In the simplest case,
‘__init__.py’ can just be an empty file, but it can also execute
initialization code for the package or set the ‘__all__’ variable,
described later.

Users of the package can import individual modules from the package, for
example:

     import sound.effects.echo

This loads the submodule ‘sound.effects.echo’.  It must be referenced
with its full name.

     sound.effects.echo.echofilter(input, output, delay=0.7, atten=4)

An alternative way of importing the submodule is:

     from sound.effects import echo

This also loads the submodule ‘echo’, and makes it available without its
package prefix, so it can be used as follows:

     echo.echofilter(input, output, delay=0.7, atten=4)

Yet another variation is to import the desired function or variable
directly:

     from sound.effects.echo import echofilter

Again, this loads the submodule ‘echo’, but this makes its function
‘echofilter()’ directly available:

     echofilter(input, output, delay=0.7, atten=4)

Note that when using ‘from package import item’, the item can be either
a submodule (or subpackage) of the package, or some other name defined
in the package, like a function, class or variable.  The ‘import’
statement first tests whether the item is defined in the package; if
not, it assumes it is a module and attempts to load it.  If it fails to
find it, an *note ImportError: 41c. exception is raised.

Contrarily, when using syntax like ‘import item.subitem.subsubitem’,
each item except for the last must be a package; the last item can be a
module or a package but can’t be a class or function or variable defined
in the previous item.

* Menu:

* Importing * From a Package::
* Intra-package References::
* Packages in Multiple Directories::


File: python.info,  Node: Importing * From a Package,  Next: Intra-package References,  Up: Packages

2.6.4.1 Importing * From a Package
..................................

Now what happens when the user writes ‘from sound.effects import *’?
Ideally, one would hope that this somehow goes out to the filesystem,
finds which submodules are present in the package, and imports them all.
This could take a long time and importing sub-modules might have
unwanted side-effects that should only happen when the sub-module is
explicitly imported.

The only solution is for the package author to provide an explicit index
of the package.  The *note import: 5e5. statement uses the following
convention: if a package’s ‘__init__.py’ code defines a list named
‘__all__’, it is taken to be the list of module names that should be
imported when ‘from package import *’ is encountered.  It is up to the
package author to keep this list up-to-date when a new version of the
package is released.  Package authors may also decide not to support it,
if they don’t see a use for importing * from their package.  For
example, the file ‘sound/effects/__init__.py’ could contain the
following code:

     __all__ = ["echo", "surround", "reverse"]

This would mean that ‘from sound.effects import *’ would import the
three named submodules of the ‘sound.effects’ package.

Be aware that submodules might become shadowed by locally defined names.
For example, if you added a ‘reverse’ function to the
‘sound/effects/__init__.py’ file, the ‘from sound.effects import *’
would only import the two submodules ‘echo’ and ‘surround’, but 'not'
the ‘reverse’ submodule, because it is shadowed by the locally defined
‘reverse’ function:

     __all__ = [
         "echo",      # refers to the 'echo.py' file
         "surround",  # refers to the 'surround.py' file
         "reverse",   # !!! refers to the 'reverse' function now !!!
     ]

     def reverse(msg: str):  # <-- this name shadows the 'reverse.py' submodule
         return msg[::-1]    #     in the case of a 'from sound.effects import *'

If ‘__all__’ is not defined, the statement ‘from sound.effects import *’
does 'not' import all submodules from the package ‘sound.effects’ into
the current namespace; it only ensures that the package ‘sound.effects’
has been imported (possibly running any initialization code in
‘__init__.py’) and then imports whatever names are defined in the
package.  This includes any names defined (and submodules explicitly
loaded) by ‘__init__.py’.  It also includes any submodules of the
package that were explicitly loaded by previous *note import: 5e5.
statements.  Consider this code:

     import sound.effects.echo
     import sound.effects.surround
     from sound.effects import *

In this example, the ‘echo’ and ‘surround’ modules are imported in the
current namespace because they are defined in the ‘sound.effects’
package when the ‘from...import’ statement is executed.  (This also
works when ‘__all__’ is defined.)

Although certain modules are designed to export only names that follow
certain patterns when you use ‘import *’, it is still considered bad
practice in production code.

Remember, there is nothing wrong with using ‘from package import
specific_submodule’!  In fact, this is the recommended notation unless
the importing module needs to use submodules with the same name from
different packages.


File: python.info,  Node: Intra-package References,  Next: Packages in Multiple Directories,  Prev: Importing * From a Package,  Up: Packages

2.6.4.2 Intra-package References
................................

When packages are structured into subpackages (as with the ‘sound’
package in the example), you can use absolute imports to refer to
submodules of siblings packages.  For example, if the module
‘sound.filters.vocoder’ needs to use the ‘echo’ module in the
‘sound.effects’ package, it can use ‘from sound.effects import echo’.

You can also write relative imports, with the ‘from module import name’
form of import statement.  These imports use leading dots to indicate
the current and parent packages involved in the relative import.  From
the ‘surround’ module for example, you might use:

     from . import echo
     from .. import formats
     from ..filters import equalizer

Note that relative imports are based on the name of the current module’s
package.  Since the main module does not have a package, modules
intended for use as the main module of a Python application must always
use absolute imports.


File: python.info,  Node: Packages in Multiple Directories,  Prev: Intra-package References,  Up: Packages

2.6.4.3 Packages in Multiple Directories
........................................

Packages support one more special attribute, *note __path__: 1e0c.  This
is initialized to be a *note sequence: 4f4. of strings containing the
name of the directory holding the package’s ‘__init__.py’ before the
code in that file is executed.  This variable can be modified; doing so
affects future searches for modules and subpackages contained in the
package.

While this feature is not often needed, it can be used to extend the set
of modules found in a package.


File: python.info,  Node: Input and Output,  Next: Errors and Exceptions,  Prev: Modules<2>,  Up: The Python Tutorial

2.7 Input and Output
====================

There are several ways to present the output of a program; data can be
printed in a human-readable form, or written to a file for future use.
This chapter will discuss some of the possibilities.

* Menu:

* Fancier Output Formatting::
* Reading and Writing Files::


File: python.info,  Node: Fancier Output Formatting,  Next: Reading and Writing Files,  Up: Input and Output

2.7.1 Fancier Output Formatting
-------------------------------

So far we’ve encountered two ways of writing values: 'expression
statements' and the *note print(): fae. function.  (A third way is using
the *note write(): 1e13. method of file objects; the standard output
file can be referenced as ‘sys.stdout’.  See the Library Reference for
more information on this.)

Often you’ll want more control over the formatting of your output than
simply printing space-separated values.  There are several ways to
format output.

   * To use *note formatted string literals: 1e14, begin a string with
     ‘f’ or ‘F’ before the opening quotation mark or triple quotation
     mark.  Inside this string, you can write a Python expression
     between ‘{’ and ‘}’ characters that can refer to variables or
     literal values.

          >>> year = 2016
          >>> event = 'Referendum'
          >>> f'Results of the {year} {event}'
          'Results of the 2016 Referendum'

   * The *note str.format(): 624. method of strings requires more manual
     effort.  You’ll still use ‘{’ and ‘}’ to mark where a variable will
     be substituted and can provide detailed formatting directives, but
     you’ll also need to provide the information to be formatted.  In
     the following code block there are two examples of how to format
     variables:

          >>> yes_votes = 42_572_654
          >>> total_votes = 85_705_149
          >>> percentage = yes_votes / total_votes
          >>> '{:-9} YES votes  {:2.2%}'.format(yes_votes, percentage)
          ' 42572654 YES votes  49.67%'

     Notice how the ‘yes_votes’ are padded with spaces and a negative
     sign only for negative numbers.  The example also prints
     ‘percentage’ multiplied by 100, with 2 decimal places and followed
     by a percent sign (see *note Format specification mini-language:
     1e8. for details).

   * Finally, you can do all the string handling yourself by using
     string slicing and concatenation operations to create any layout
     you can imagine.  The string type has some methods that perform
     useful operations for padding strings to a given column width.

When you don’t need fancy output but just want a quick display of some
variables for debugging purposes, you can convert any value to a string
with the *note repr(): 803. or *note str(): 44f. functions.

The *note str(): 44f. function is meant to return representations of
values which are fairly human-readable, while *note repr(): 803. is
meant to generate representations which can be read by the interpreter
(or will force a *note SyntaxError: 18d. if there is no equivalent
syntax).  For objects which don’t have a particular representation for
human consumption, ‘str()’ will return the same value as ‘repr()’.  Many
values, such as numbers or structures like lists and dictionaries, have
the same representation using either function.  Strings, in particular,
have two distinct representations.

Some examples:

     >>> s = 'Hello, world.'
     >>> str(s)
     'Hello, world.'
     >>> repr(s)
     "'Hello, world.'"
     >>> str(1/7)
     '0.14285714285714285'
     >>> x = 10 * 3.25
     >>> y = 200 * 200
     >>> s = 'The value of x is ' + repr(x) + ', and y is ' + repr(y) + '...'
     >>> print(s)
     The value of x is 32.5, and y is 40000...
     >>> # The repr() of a string adds string quotes and backslashes:
     >>> hello = 'hello, world\n'
     >>> hellos = repr(hello)
     >>> print(hellos)
     'hello, world\n'
     >>> # The argument to repr() may be any Python object:
     >>> repr((x, y, ('spam', 'eggs')))
     "(32.5, 40000, ('spam', 'eggs'))"

The *note string: d3. module contains a *note Template: 68a. class that
offers yet another way to substitute values into strings, using
placeholders like ‘$x’ and replacing them with values from a dictionary,
but offers much less control of the formatting.

* Menu:

* Formatted String Literals::
* The String format() Method: The String format Method.
* Manual String Formatting::
* Old string formatting::


File: python.info,  Node: Formatted String Literals,  Next: The String format Method,  Up: Fancier Output Formatting

2.7.1.1 Formatted String Literals
.................................

*note Formatted string literals: 9b4. (also called f-strings for short)
let you include the value of Python expressions inside a string by
prefixing the string with ‘f’ or ‘F’ and writing expressions as
‘{expression}’.

An optional format specifier can follow the expression.  This allows
greater control over how the value is formatted.  The following example
rounds pi to three places after the decimal:

     >>> import math
     >>> print(f'The value of pi is approximately {math.pi:.3f}.')
     The value of pi is approximately 3.142.

Passing an integer after the ‘':'’ will cause that field to be a minimum
number of characters wide.  This is useful for making columns line up.

     >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 7678}
     >>> for name, phone in table.items():
     ...     print(f'{name:10} ==> {phone:10d}')
     ...
     Sjoerd     ==>       4127
     Jack       ==>       4098
     Dcab       ==>       7678

Other modifiers can be used to convert the value before it is formatted.
‘'!a'’ applies *note ascii(): 1434, ‘'!s'’ applies *note str(): 44f, and
‘'!r'’ applies *note repr(): 803.:

     >>> animals = 'eels'
     >>> print(f'My hovercraft is full of {animals}.')
     My hovercraft is full of eels.
     >>> print(f'My hovercraft is full of {animals!r}.')
     My hovercraft is full of 'eels'.

The ‘=’ specifier can be used to expand an expression to the text of the
expression, an equal sign, then the representation of the evaluated
expression:

     >>> bugs = 'roaches'
     >>> count = 13
     >>> area = 'living room'
     >>> print(f'Debugging {bugs=} {count=} {area=}')
     Debugging bugs='roaches' count=13 area='living room'

See *note self-documenting expressions: 9b2. for more information on the
‘=’ specifier.  For a reference on these format specifications, see the
reference guide for the *note Format specification mini-language: 1e8.


File: python.info,  Node: The String format Method,  Next: Manual String Formatting,  Prev: Formatted String Literals,  Up: Fancier Output Formatting

2.7.1.2 The String format() Method
..................................

Basic usage of the *note str.format(): 624. method looks like this:

     >>> print('We are the {} who say "{}!"'.format('knights', 'Ni'))
     We are the knights who say "Ni!"

The brackets and characters within them (called format fields) are
replaced with the objects passed into the *note str.format(): 624.
method.  A number in the brackets can be used to refer to the position
of the object passed into the ‘str.format()’ method.

     >>> print('{0} and {1}'.format('spam', 'eggs'))
     spam and eggs
     >>> print('{1} and {0}'.format('spam', 'eggs'))
     eggs and spam

If keyword arguments are used in the *note str.format(): 624. method,
their values are referred to by using the name of the argument.

     >>> print('This {food} is {adjective}.'.format(
     ...       food='spam', adjective='absolutely horrible'))
     This spam is absolutely horrible.

Positional and keyword arguments can be arbitrarily combined:

     >>> print('The story of {0}, {1}, and {other}.'.format('Bill', 'Manfred',
     ...                                                    other='Georg'))
     The story of Bill, Manfred, and Georg.

If you have a really long format string that you don’t want to split up,
it would be nice if you could reference the variables to be formatted by
name instead of by position.  This can be done by simply passing the
dict and using square brackets ‘'[]'’ to access the keys.

     >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
     >>> print('Jack: {0[Jack]:d}; Sjoerd: {0[Sjoerd]:d}; '
     ...       'Dcab: {0[Dcab]:d}'.format(table))
     Jack: 4098; Sjoerd: 4127; Dcab: 8637678

This could also be done by passing the ‘table’ dictionary as keyword
arguments with the ‘**’ notation.

     >>> table = {'Sjoerd': 4127, 'Jack': 4098, 'Dcab': 8637678}
     >>> print('Jack: {Jack:d}; Sjoerd: {Sjoerd:d}; Dcab: {Dcab:d}'.format(**table))
     Jack: 4098; Sjoerd: 4127; Dcab: 8637678

This is particularly useful in combination with the built-in function
*note vars(): 1bd2, which returns a dictionary containing all local
variables:

     >>> table = {k: str(v) for k, v in vars().items()}
     >>> message = " ".join([f'{k}: ' + '{' + k +'};' for k in table.keys()])
     >>> print(message.format(**table))
     __name__: __main__; __doc__: None; __package__: None; __loader__: ...

As an example, the following lines produce a tidily aligned set of
columns giving integers and their squares and cubes:

     >>> for x in range(1, 11):
     ...     print('{0:2d} {1:3d} {2:4d}'.format(x, x*x, x*x*x))
     ...
      1   1    1
      2   4    8
      3   9   27
      4  16   64
      5  25  125
      6  36  216
      7  49  343
      8  64  512
      9  81  729
     10 100 1000

For a complete overview of string formatting with *note str.format():
624, see *note Format string syntax: 13e8.


File: python.info,  Node: Manual String Formatting,  Next: Old string formatting,  Prev: The String format Method,  Up: Fancier Output Formatting

2.7.1.3 Manual String Formatting
................................

Here’s the same table of squares and cubes, formatted manually:

     >>> for x in range(1, 11):
     ...     print(repr(x).rjust(2), repr(x*x).rjust(3), end=' ')
     ...     # Note use of 'end' on previous line
     ...     print(repr(x*x*x).rjust(4))
     ...
      1   1    1
      2   4    8
      3   9   27
      4  16   64
      5  25  125
      6  36  216
      7  49  343
      8  64  512
      9  81  729
     10 100 1000

(Note that the one space between each column was added by the way *note
print(): fae. works: it always adds spaces between its arguments.)

The *note str.rjust(): 1e19. method of string objects right-justifies a
string in a field of a given width by padding it with spaces on the
left.  There are similar methods *note str.ljust(): 1e1a. and *note
str.center(): 1e1b.  These methods do not write anything, they just
return a new string.  If the input string is too long, they don’t
truncate it, but return it unchanged; this will mess up your column
lay-out but that’s usually better than the alternative, which would be
lying about a value.  (If you really want truncation you can always add
a slice operation, as in ‘x.ljust(n)[:n]’.)

There is another method, *note str.zfill(): 1501, which pads a numeric
string on the left with zeros.  It understands about plus and minus
signs:

     >>> '12'.zfill(5)
     '00012'
     >>> '-3.14'.zfill(7)
     '-003.14'
     >>> '3.14159265359'.zfill(5)
     '3.14159265359'


File: python.info,  Node: Old string formatting,  Prev: Manual String Formatting,  Up: Fancier Output Formatting

2.7.1.4 Old string formatting
.............................

The % operator (modulo) can also be used for string formatting.  Given
‘format % values’ (where 'format' is a string), ‘%’ conversion
specifications in 'format' are replaced with zero or more elements of
'values'.  This operation is commonly known as string interpolation.
For example:

     >>> import math
     >>> print('The value of pi is approximately %5.3f.' % math.pi)
     The value of pi is approximately 3.142.

More information can be found in the *note printf-style String
Formatting: 6cf. section.


File: python.info,  Node: Reading and Writing Files,  Prev: Fancier Output Formatting,  Up: Input and Output

2.7.2 Reading and Writing Files
-------------------------------

*note open(): 51f. returns a *note file object: 1208, and is most
commonly used with two positional arguments and one keyword argument:
‘open(filename, mode, encoding=None)’

     >>> f = open('workfile', 'w', encoding="utf-8")

The first argument is a string containing the filename.  The second
argument is another string containing a few characters describing the
way in which the file will be used.  'mode' can be ‘'r'’ when the file
will only be read, ‘'w'’ for only writing (an existing file with the
same name will be erased), and ‘'a'’ opens the file for appending; any
data written to the file is automatically added to the end.  ‘'r+'’
opens the file for both reading and writing.  The 'mode' argument is
optional; ‘'r'’ will be assumed if it’s omitted.

Normally, files are opened in 'text mode', that means, you read and
write strings from and to the file, which are encoded in a specific
'encoding'.  If 'encoding' is not specified, the default is platform
dependent (see *note open(): 51f.).  Because UTF-8 is the modern
de-facto standard, ‘encoding="utf-8"’ is recommended unless you know
that you need to use a different encoding.  Appending a ‘'b'’ to the
mode opens the file in 'binary mode'.  Binary mode data is read and
written as *note bytes: 1c2. objects.  You can not specify 'encoding'
when opening file in binary mode.

In text mode, the default when reading is to convert platform-specific
line endings (‘\n’ on Unix, ‘\r\n’ on Windows) to just ‘\n’.  When
writing in text mode, the default is to convert occurrences of ‘\n’ back
to platform-specific line endings.  This behind-the-scenes modification
to file data is fine for text files, but will corrupt binary data like
that in ‘JPEG’ or ‘EXE’ files.  Be very careful to use binary mode when
reading and writing such files.

It is good practice to use the *note with: 5d5. keyword when dealing
with file objects.  The advantage is that the file is properly closed
after its suite finishes, even if an exception is raised at some point.
Using ‘with’ is also much shorter than writing equivalent *note try:
6ec.-*note finally: 9d5. blocks:

     >>> with open('workfile', encoding="utf-8") as f:
     ...     read_data = f.read()

     >>> # We can check that the file has been automatically closed.
     >>> f.closed
     True

If you’re not using the *note with: 5d5. keyword, then you should call
‘f.close()’ to close the file and immediately free up any system
resources used by it.

     Warning: Calling ‘f.write()’ without using the ‘with’ keyword or
     calling ‘f.close()’ 'might' result in the arguments of ‘f.write()’
     not being completely written to the disk, even if the program exits
     successfully.

After a file object is closed, either by a *note with: 5d5. statement or
by calling ‘f.close()’, attempts to use the file object will
automatically fail.

     >>> f.close()
     >>> f.read()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ValueError: I/O operation on closed file.

* Menu:

* Methods of File Objects::
* Saving structured data with json::


File: python.info,  Node: Methods of File Objects,  Next: Saving structured data with json,  Up: Reading and Writing Files

2.7.2.1 Methods of File Objects
...............................

The rest of the examples in this section will assume that a file object
called ‘f’ has already been created.

To read a file’s contents, call ‘f.read(size)’, which reads some
quantity of data and returns it as a string (in text mode) or bytes
object (in binary mode).  'size' is an optional numeric argument.  When
'size' is omitted or negative, the entire contents of the file will be
read and returned; it’s your problem if the file is twice as large as
your machine’s memory.  Otherwise, at most 'size' characters (in text
mode) or 'size' bytes (in binary mode) are read and returned.  If the
end of the file has been reached, ‘f.read()’ will return an empty string
(‘''’).

     >>> f.read()
     'This is the entire file.\n'
     >>> f.read()
     ''

‘f.readline()’ reads a single line from the file; a newline character
(‘\n’) is left at the end of the string, and is only omitted on the last
line of the file if the file doesn’t end in a newline.  This makes the
return value unambiguous; if ‘f.readline()’ returns an empty string, the
end of the file has been reached, while a blank line is represented by
‘'\n'’, a string containing only a single newline.

     >>> f.readline()
     'This is the first line of the file.\n'
     >>> f.readline()
     'Second line of the file\n'
     >>> f.readline()
     ''

For reading lines from a file, you can loop over the file object.  This
is memory efficient, fast, and leads to simple code:

     >>> for line in f:
     ...     print(line, end='')
     ...
     This is the first line of the file.
     Second line of the file

If you want to read all the lines of a file in a list you can also use
‘list(f)’ or ‘f.readlines()’.

‘f.write(string)’ writes the contents of 'string' to the file, returning
the number of characters written.

     >>> f.write('This is a test\n')
     15

Other types of objects need to be converted – either to a string (in
text mode) or a bytes object (in binary mode) – before writing them:

     >>> value = ('the answer', 42)
     >>> s = str(value)  # convert the tuple to string
     >>> f.write(s)
     18

‘f.tell()’ returns an integer giving the file object’s current position
in the file represented as number of bytes from the beginning of the
file when in binary mode and an opaque number when in text mode.

To change the file object’s position, use ‘f.seek(offset, whence)’.  The
position is computed from adding 'offset' to a reference point; the
reference point is selected by the 'whence' argument.  A 'whence' value
of 0 measures from the beginning of the file, 1 uses the current file
position, and 2 uses the end of the file as the reference point.
'whence' can be omitted and defaults to 0, using the beginning of the
file as the reference point.

     >>> f = open('workfile', 'rb+')
     >>> f.write(b'0123456789abcdef')
     16
     >>> f.seek(5)      # Go to the 6th byte in the file
     5
     >>> f.read(1)
     b'5'
     >>> f.seek(-3, 2)  # Go to the 3rd byte before the end
     13
     >>> f.read(1)
     b'd'

In text files (those opened without a ‘b’ in the mode string), only
seeks relative to the beginning of the file are allowed (the exception
being seeking to the very file end with ‘seek(0, 2)’) and the only valid
'offset' values are those returned from the ‘f.tell()’, or zero.  Any
other 'offset' value produces undefined behaviour.

File objects have some additional methods, such as *note isatty(): 1e21.
and *note truncate(): 135a. which are less frequently used; consult the
Library Reference for a complete guide to file objects.


File: python.info,  Node: Saving structured data with json,  Prev: Methods of File Objects,  Up: Reading and Writing Files

2.7.2.2 Saving structured data with ‘json’
..........................................

Strings can easily be written to and read from a file.  Numbers take a
bit more effort, since the *note read(): 1e24. method only returns
strings, which will have to be passed to a function like *note int():
257, which takes a string like ‘'123'’ and returns its numeric value
123.  When you want to save more complex data types like nested lists
and dictionaries, parsing and serializing by hand becomes complicated.

Rather than having users constantly writing and debugging code to save
complicated data types to files, Python allows you to use the popular
data interchange format called JSON (JavaScript Object Notation)(1).
The standard module called *note json: 82. can take Python data
hierarchies, and convert them to string representations; this process is
called 'serializing'.  Reconstructing the data from the string
representation is called 'deserializing'.  Between serializing and
deserializing, the string representing the object may have been stored
in a file or data, or sent over a network connection to some distant
machine.

     Note: The JSON format is commonly used by modern applications to
     allow for data exchange.  Many programmers are already familiar
     with it, which makes it a good choice for interoperability.

If you have an object ‘x’, you can view its JSON string representation
with a simple line of code:

     >>> import json
     >>> x = [1, 'simple', 'list']
     >>> json.dumps(x)
     '[1, "simple", "list"]'

Another variant of the *note dumps(): d6e. function, called *note
dump(): d6d, simply serializes the object to a *note text file: 1e25.
So if ‘f’ is a text file object opened for writing, we can do this:

     json.dump(x, f)

To decode the object again, if ‘f’ is a *note binary file: 1e26. or
*note text file: 1e25. object which has been opened for reading:

     x = json.load(f)

     Note: JSON files must be encoded in UTF-8.  Use ‘encoding="utf-8"’
     when opening JSON file as a *note text file: 1e25. for both of
     reading and writing.

This simple serialization technique can handle lists and dictionaries,
but serializing arbitrary class instances in JSON requires a bit of
extra effort.  The reference for the *note json: 82. module contains an
explanation of this.

See also
........

*note pickle: a6. - the pickle module

Contrary to *note JSON: 1e23, 'pickle' is a protocol which allows the
serialization of arbitrarily complex Python objects.  As such, it is
specific to Python and cannot be used to communicate with applications
written in other languages.  It is also insecure by default:
deserializing pickle data coming from an untrusted source can execute
arbitrary code, if the data was crafted by a skilled attacker.

   ---------- Footnotes ----------

   (1) https://json.org


File: python.info,  Node: Errors and Exceptions,  Next: Classes,  Prev: Input and Output,  Up: The Python Tutorial

2.8 Errors and Exceptions
=========================

Until now error messages haven’t been more than mentioned, but if you
have tried out the examples you have probably seen some.  There are (at
least) two distinguishable kinds of errors: 'syntax errors' and
'exceptions'.

* Menu:

* Syntax Errors::
* Exceptions::
* Handling Exceptions::
* Raising Exceptions::
* Exception Chaining::
* User-defined Exceptions::
* Defining Clean-up Actions::
* Predefined Clean-up Actions::
* Raising and Handling Multiple Unrelated Exceptions::
* Enriching Exceptions with Notes::


File: python.info,  Node: Syntax Errors,  Next: Exceptions,  Up: Errors and Exceptions

2.8.1 Syntax Errors
-------------------

Syntax errors, also known as parsing errors, are perhaps the most common
kind of complaint you get while you are still learning Python:

     >>> while True print('Hello world')
       File "<stdin>", line 1
         while True print('Hello world')
                    ^^^^^
     SyntaxError: invalid syntax

The parser repeats the offending line and displays little arrows
pointing at the place where the error was detected.  Note that this is
not always the place that needs to be fixed.  In the example, the error
is detected at the function *note print(): fae, since a colon (‘':'’) is
missing just before it.

The file name (‘<stdin>’ in our example) and line number are printed so
you know where to look in case the input came from a file.


File: python.info,  Node: Exceptions,  Next: Handling Exceptions,  Prev: Syntax Errors,  Up: Errors and Exceptions

2.8.2 Exceptions
----------------

Even if a statement or expression is syntactically correct, it may cause
an error when an attempt is made to execute it.  Errors detected during
execution are called 'exceptions' and are not unconditionally fatal: you
will soon learn how to handle them in Python programs.  Most exceptions
are not handled by programs, however, and result in error messages as
shown here:

     >>> 10 * (1/0)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         10 * (1/0)
               ~^~
     ZeroDivisionError: division by zero
     >>> 4 + spam*3
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         4 + spam*3
             ^^^^
     NameError: name 'spam' is not defined
     >>> '2' + 2
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         '2' + 2
         ~~~~^~~
     TypeError: can only concatenate str (not "int") to str

The last line of the error message indicates what happened.  Exceptions
come in different types, and the type is printed as part of the message:
the types in the example are *note ZeroDivisionError: 94f, *note
NameError: 442. and *note TypeError: 2c3.  The string printed as the
exception type is the name of the built-in exception that occurred.
This is true for all built-in exceptions, but need not be true for
user-defined exceptions (although it is a useful convention).  Standard
exception names are built-in identifiers (not reserved keywords).

The rest of the line provides detail based on the type of exception and
what caused it.

The preceding part of the error message shows the context where the
exception occurred, in the form of a stack traceback.  In general it
contains a stack traceback listing source lines; however, it will not
display lines read from standard input.

*note Built-in Exceptions: 19cc. lists the built-in exceptions and their
meanings.


File: python.info,  Node: Handling Exceptions,  Next: Raising Exceptions,  Prev: Exceptions,  Up: Errors and Exceptions

2.8.3 Handling Exceptions
-------------------------

It is possible to write programs that handle selected exceptions.  Look
at the following example, which asks the user for input until a valid
integer has been entered, but allows the user to interrupt the program
(using ‘Control’-‘C’ or whatever the operating system supports); note
that a user-generated interruption is signalled by raising the *note
KeyboardInterrupt: 9dc. exception.

     >>> while True:
     ...     try:
     ...         x = int(input("Please enter a number: "))
     ...         break
     ...     except ValueError:
     ...         print("Oops!  That was no valid number.  Try again...")
     ...

The *note try: 6ec. statement works as follows.

   * First, the 'try clause' (the statement(s) between the *note try:
     6ec. and *note except: 18b. keywords) is executed.

   * If no exception occurs, the 'except clause' is skipped and
     execution of the *note try: 6ec. statement is finished.

   * If an exception occurs during execution of the *note try: 6ec.
     clause, the rest of the clause is skipped.  Then, if its type
     matches the exception named after the *note except: 18b. keyword,
     the 'except clause' is executed, and then execution continues after
     the try/except block.

   * If an exception occurs which does not match the exception named in
     the 'except clause', it is passed on to outer *note try: 6ec.
     statements; if no handler is found, it is an 'unhandled exception'
     and execution stops with an error message.

A *note try: 6ec. statement may have more than one 'except clause', to
specify handlers for different exceptions.  At most one handler will be
executed.  Handlers only handle exceptions that occur in the
corresponding 'try clause', not in other handlers of the same ‘try’
statement.  An 'except clause' may name multiple exceptions as a
parenthesized tuple, for example:

     ... except (RuntimeError, TypeError, NameError):
     ...     pass

A class in an *note except: 18b. clause matches exceptions which are
instances of the class itself or one of its derived classes (but not the
other way around — an 'except clause' listing a derived class does not
match instances of its base classes).  For example, the following code
will print B, C, D in that order:

     class B(Exception):
         pass

     class C(B):
         pass

     class D(C):
         pass

     for cls in [B, C, D]:
         try:
             raise cls()
         except D:
             print("D")
         except C:
             print("C")
         except B:
             print("B")

Note that if the 'except clauses' were reversed (with ‘except B’ first),
it would have printed B, B, B — the first matching 'except clause' is
triggered.

When an exception occurs, it may have associated values, also known as
the exception’s 'arguments'.  The presence and types of the arguments
depend on the exception type.

The 'except clause' may specify a variable after the exception name.
The variable is bound to the exception instance which typically has an
‘args’ attribute that stores the arguments.  For convenience, builtin
exception types define *note __str__(): 620. to print all the arguments
without explicitly accessing ‘.args’.

     >>> try:
     ...     raise Exception('spam', 'eggs')
     ... except Exception as inst:
     ...     print(type(inst))    # the exception type
     ...     print(inst.args)     # arguments stored in .args
     ...     print(inst)          # __str__ allows args to be printed directly,
     ...                          # but may be overridden in exception subclasses
     ...     x, y = inst.args     # unpack args
     ...     print('x =', x)
     ...     print('y =', y)
     ...
     <class 'Exception'>
     ('spam', 'eggs')
     ('spam', 'eggs')
     x = spam
     y = eggs

The exception’s *note __str__(): 620. output is printed as the last part
(‘detail’) of the message for unhandled exceptions.

*note BaseException: 5be. is the common base class of all exceptions.
One of its subclasses, *note Exception: 9e5, is the base class of all
the non-fatal exceptions.  Exceptions which are not subclasses of
‘Exception’ are not typically handled, because they are used to indicate
that the program should terminate.  They include *note SystemExit: d69.
which is raised by *note sys.exit(): 1394. and *note KeyboardInterrupt:
9dc. which is raised when a user wishes to interrupt the program.

*note Exception: 9e5. can be used as a wildcard that catches (almost)
everything.  However, it is good practice to be as specific as possible
with the types of exceptions that we intend to handle, and to allow any
unexpected exceptions to propagate on.

The most common pattern for handling *note Exception: 9e5. is to print
or log the exception and then re-raise it (allowing a caller to handle
the exception as well):

     import sys

     try:
         f = open('myfile.txt')
         s = f.readline()
         i = int(s.strip())
     except OSError as err:
         print("OS error:", err)
     except ValueError:
         print("Could not convert data to an integer.")
     except Exception as err:
         print(f"Unexpected {err=}, {type(err)=}")
         raise

The *note try: 6ec. … *note except: 18b. statement has an optional 'else
clause', which, when present, must follow all 'except clauses'.  It is
useful for code that must be executed if the 'try clause' does not raise
an exception.  For example:

     for arg in sys.argv[1:]:
         try:
             f = open(arg, 'r')
         except OSError:
             print('cannot open', arg)
         else:
             print(arg, 'has', len(f.readlines()), 'lines')
             f.close()

The use of the ‘else’ clause is better than adding additional code to
the *note try: 6ec. clause because it avoids accidentally catching an
exception that wasn’t raised by the code being protected by the ‘try’ …
‘except’ statement.

Exception handlers do not handle only exceptions that occur immediately
in the 'try clause', but also those that occur inside functions that are
called (even indirectly) in the 'try clause'.  For example:

     >>> def this_fails():
     ...     x = 1/0
     ...
     >>> try:
     ...     this_fails()
     ... except ZeroDivisionError as err:
     ...     print('Handling run-time error:', err)
     ...
     Handling run-time error: division by zero


File: python.info,  Node: Raising Exceptions,  Next: Exception Chaining,  Prev: Handling Exceptions,  Up: Errors and Exceptions

2.8.4 Raising Exceptions
------------------------

The *note raise: 5f0. statement allows the programmer to force a
specified exception to occur.  For example:

     >>> raise NameError('HiThere')
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         raise NameError('HiThere')
     NameError: HiThere

The sole argument to *note raise: 5f0. indicates the exception to be
raised.  This must be either an exception instance or an exception class
(a class that derives from *note BaseException: 5be, such as *note
Exception: 9e5. or one of its subclasses).  If an exception class is
passed, it will be implicitly instantiated by calling its constructor
with no arguments:

     raise ValueError  # shorthand for 'raise ValueError()'

If you need to determine whether an exception was raised but don’t
intend to handle it, a simpler form of the *note raise: 5f0. statement
allows you to re-raise the exception:

     >>> try:
     ...     raise NameError('HiThere')
     ... except NameError:
     ...     print('An exception flew by!')
     ...     raise
     ...
     An exception flew by!
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         raise NameError('HiThere')
     NameError: HiThere


File: python.info,  Node: Exception Chaining,  Next: User-defined Exceptions,  Prev: Raising Exceptions,  Up: Errors and Exceptions

2.8.5 Exception Chaining
------------------------

If an unhandled exception occurs inside an *note except: 18b. section,
it will have the exception being handled attached to it and included in
the error message:

     >>> try:
     ...     open("database.sqlite")
     ... except OSError:
     ...     raise RuntimeError("unable to handle error")
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         open("database.sqlite")
         ~~~~^^^^^^^^^^^^^^^^^^^
     FileNotFoundError: [Errno 2] No such file or directory: 'database.sqlite'

     During handling of the above exception, another exception occurred:

     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
         raise RuntimeError("unable to handle error")
     RuntimeError: unable to handle error

To indicate that an exception is a direct consequence of another, the
*note raise: 5f0. statement allows an optional ‘from’ clause:

     # exc must be exception instance or None.
     raise RuntimeError from exc

This can be useful when you are transforming exceptions.  For example:

     >>> def func():
     ...     raise ConnectionError
     ...
     >>> try:
     ...     func()
     ... except ConnectionError as exc:
     ...     raise RuntimeError('Failed to open database') from exc
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         func()
         ~~~~^^
       File "<stdin>", line 2, in func
     ConnectionError

     The above exception was the direct cause of the following exception:

     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
         raise RuntimeError('Failed to open database') from exc
     RuntimeError: Failed to open database

It also allows disabling automatic exception chaining using the ‘from
None’ idiom:

     >>> try:
     ...     open('database.sqlite')
     ... except OSError:
     ...     raise RuntimeError from None
     ...
     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
         raise RuntimeError from None
     RuntimeError

For more information about chaining mechanics, see *note Built-in
Exceptions: 19cc.


File: python.info,  Node: User-defined Exceptions,  Next: Defining Clean-up Actions,  Prev: Exception Chaining,  Up: Errors and Exceptions

2.8.6 User-defined Exceptions
-----------------------------

Programs may name their own exceptions by creating a new exception class
(see *note Classes: 1db7. for more about Python classes).  Exceptions
should typically be derived from the *note Exception: 9e5. class, either
directly or indirectly.

Exception classes can be defined which do anything any other class can
do, but are usually kept simple, often only offering a number of
attributes that allow information about the error to be extracted by
handlers for the exception.

Most exceptions are defined with names that end in “Error”, similar to
the naming of the standard exceptions.

Many standard modules define their own exceptions to report errors that
may occur in functions they define.


File: python.info,  Node: Defining Clean-up Actions,  Next: Predefined Clean-up Actions,  Prev: User-defined Exceptions,  Up: Errors and Exceptions

2.8.7 Defining Clean-up Actions
-------------------------------

The *note try: 6ec. statement has another optional clause which is
intended to define clean-up actions that must be executed under all
circumstances.  For example:

     >>> try:
     ...     raise KeyboardInterrupt
     ... finally:
     ...     print('Goodbye, world!')
     ...
     Goodbye, world!
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         raise KeyboardInterrupt
     KeyboardInterrupt

If a *note finally: 9d5. clause is present, the ‘finally’ clause will
execute as the last task before the *note try: 6ec. statement completes.
The ‘finally’ clause runs whether or not the ‘try’ statement produces an
exception.  The following points discuss more complex cases when an
exception occurs:

   * If an exception occurs during execution of the ‘try’ clause, the
     exception may be handled by an *note except: 18b. clause.  If the
     exception is not handled by an ‘except’ clause, the exception is
     re-raised after the ‘finally’ clause has been executed.

   * An exception could occur during execution of an ‘except’ or ‘else’
     clause.  Again, the exception is re-raised after the ‘finally’
     clause has been executed.

   * If the ‘finally’ clause executes a *note break: abe, *note
     continue: 9d4. or *note return: 9d9. statement, exceptions are not
     re-raised.

   * If the ‘try’ statement reaches a *note break: abe, *note continue:
     9d4. or *note return: 9d9. statement, the ‘finally’ clause will
     execute just prior to the ‘break’, ‘continue’ or ‘return’
     statement’s execution.

   * If a ‘finally’ clause includes a ‘return’ statement, the returned
     value will be the one from the ‘finally’ clause’s ‘return’
     statement, not the value from the ‘try’ clause’s ‘return’
     statement.

For example:

     >>> def bool_return():
     ...     try:
     ...         return True
     ...     finally:
     ...         return False
     ...
     >>> bool_return()
     False

A more complicated example:

     >>> def divide(x, y):
     ...     try:
     ...         result = x / y
     ...     except ZeroDivisionError:
     ...         print("division by zero!")
     ...     else:
     ...         print("result is", result)
     ...     finally:
     ...         print("executing finally clause")
     ...
     >>> divide(2, 1)
     result is 2.0
     executing finally clause
     >>> divide(2, 0)
     division by zero!
     executing finally clause
     >>> divide("2", "1")
     executing finally clause
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         divide("2", "1")
         ~~~~~~^^^^^^^^^^
       File "<stdin>", line 3, in divide
         result = x / y
                  ~~^~~
     TypeError: unsupported operand type(s) for /: 'str' and 'str'

As you can see, the *note finally: 9d5. clause is executed in any event.
The *note TypeError: 2c3. raised by dividing two strings is not handled
by the *note except: 18b. clause and therefore re-raised after the
‘finally’ clause has been executed.

In real world applications, the *note finally: 9d5. clause is useful for
releasing external resources (such as files or network connections),
regardless of whether the use of the resource was successful.


File: python.info,  Node: Predefined Clean-up Actions,  Next: Raising and Handling Multiple Unrelated Exceptions,  Prev: Defining Clean-up Actions,  Up: Errors and Exceptions

2.8.8 Predefined Clean-up Actions
---------------------------------

Some objects define standard clean-up actions to be undertaken when the
object is no longer needed, regardless of whether or not the operation
using the object succeeded or failed.  Look at the following example,
which tries to open a file and print its contents to the screen.

     for line in open("myfile.txt"):
         print(line, end="")

The problem with this code is that it leaves the file open for an
indeterminate amount of time after this part of the code has finished
executing.  This is not an issue in simple scripts, but can be a problem
for larger applications.  The *note with: 5d5. statement allows objects
like files to be used in a way that ensures they are always cleaned up
promptly and correctly.

     with open("myfile.txt") as f:
         for line in f:
             print(line, end="")

After the statement is executed, the file 'f' is always closed, even if
a problem was encountered while processing the lines.  Objects which,
like files, provide predefined clean-up actions will indicate this in
their documentation.


File: python.info,  Node: Raising and Handling Multiple Unrelated Exceptions,  Next: Enriching Exceptions with Notes,  Prev: Predefined Clean-up Actions,  Up: Errors and Exceptions

2.8.9 Raising and Handling Multiple Unrelated Exceptions
--------------------------------------------------------

There are situations where it is necessary to report several exceptions
that have occurred.  This is often the case in concurrency frameworks,
when several tasks may have failed in parallel, but there are also other
use cases where it is desirable to continue execution and collect
multiple errors rather than raise the first exception.

The builtin *note ExceptionGroup: 1b6. wraps a list of exception
instances so that they can be raised together.  It is an exception
itself, so it can be caught like any other exception.

     >>> def f():
     ...     excs = [OSError('error 1'), SystemError('error 2')]
     ...     raise ExceptionGroup('there were problems', excs)
     ...
     >>> f()
       + Exception Group Traceback (most recent call last):
       |   File "<stdin>", line 1, in <module>
       |     f()
       |     ~^^
       |   File "<stdin>", line 3, in f
       |     raise ExceptionGroup('there were problems', excs)
       | ExceptionGroup: there were problems (2 sub-exceptions)
       +-+---------------- 1 ----------------
         | OSError: error 1
         +---------------- 2 ----------------
         | SystemError: error 2
         +------------------------------------
     >>> try:
     ...     f()
     ... except Exception as e:
     ...     print(f'caught {type(e)}: {e}')
     ...
     caught <class 'ExceptionGroup'>: there were problems (2 sub-exceptions)
     >>>

By using ‘except*’ instead of ‘except’, we can selectively handle only
the exceptions in the group that match a certain type.  In the following
example, which shows a nested exception group, each ‘except*’ clause
extracts from the group exceptions of a certain type while letting all
other exceptions propagate to other clauses and eventually to be
reraised.

     >>> def f():
     ...     raise ExceptionGroup(
     ...         "group1",
     ...         [
     ...             OSError(1),
     ...             SystemError(2),
     ...             ExceptionGroup(
     ...                 "group2",
     ...                 [
     ...                     OSError(3),
     ...                     RecursionError(4)
     ...                 ]
     ...             )
     ...         ]
     ...     )
     ...
     >>> try:
     ...     f()
     ... except* OSError as e:
     ...     print("There were OSErrors")
     ... except* SystemError as e:
     ...     print("There were SystemErrors")
     ...
     There were OSErrors
     There were SystemErrors
       + Exception Group Traceback (most recent call last):
       |   File "<stdin>", line 2, in <module>
       |     f()
       |     ~^^
       |   File "<stdin>", line 2, in f
       |     raise ExceptionGroup(
       |     ...<12 lines>...
       |     )
       | ExceptionGroup: group1 (1 sub-exception)
       +-+---------------- 1 ----------------
         | ExceptionGroup: group2 (1 sub-exception)
         +-+---------------- 1 ----------------
           | RecursionError: 4
           +------------------------------------
     >>>

Note that the exceptions nested in an exception group must be instances,
not types.  This is because in practice the exceptions would typically
be ones that have already been raised and caught by the program, along
the following pattern:

     >>> excs = []
     ... for test in tests:
     ...     try:
     ...         test.run()
     ...     except Exception as e:
     ...         excs.append(e)
     ...
     >>> if excs:
     ...    raise ExceptionGroup("Test Failures", excs)
     ...


File: python.info,  Node: Enriching Exceptions with Notes,  Prev: Raising and Handling Multiple Unrelated Exceptions,  Up: Errors and Exceptions

2.8.10 Enriching Exceptions with Notes
--------------------------------------

When an exception is created in order to be raised, it is usually
initialized with information that describes the error that has occurred.
There are cases where it is useful to add information after the
exception was caught.  For this purpose, exceptions have a method
‘add_note(note)’ that accepts a string and adds it to the exception’s
notes list.  The standard traceback rendering includes all notes, in the
order they were added, after the exception.

     >>> try:
     ...     raise TypeError('bad type')
     ... except Exception as e:
     ...     e.add_note('Add some information')
     ...     e.add_note('Add some more information')
     ...     raise
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         raise TypeError('bad type')
     TypeError: bad type
     Add some information
     Add some more information
     >>>

For example, when collecting exceptions into an exception group, we may
want to add context information for the individual errors.  In the
following each exception in the group has a note indicating when this
error has occurred.

     >>> def f():
     ...     raise OSError('operation failed')
     ...
     >>> excs = []
     >>> for i in range(3):
     ...     try:
     ...         f()
     ...     except Exception as e:
     ...         e.add_note(f'Happened in Iteration {i+1}')
     ...         excs.append(e)
     ...
     >>> raise ExceptionGroup('We have some problems', excs)
       + Exception Group Traceback (most recent call last):
       |   File "<stdin>", line 1, in <module>
       |     raise ExceptionGroup('We have some problems', excs)
       | ExceptionGroup: We have some problems (3 sub-exceptions)
       +-+---------------- 1 ----------------
         | Traceback (most recent call last):
         |   File "<stdin>", line 3, in <module>
         |     f()
         |     ~^^
         |   File "<stdin>", line 2, in f
         |     raise OSError('operation failed')
         | OSError: operation failed
         | Happened in Iteration 1
         +---------------- 2 ----------------
         | Traceback (most recent call last):
         |   File "<stdin>", line 3, in <module>
         |     f()
         |     ~^^
         |   File "<stdin>", line 2, in f
         |     raise OSError('operation failed')
         | OSError: operation failed
         | Happened in Iteration 2
         +---------------- 3 ----------------
         | Traceback (most recent call last):
         |   File "<stdin>", line 3, in <module>
         |     f()
         |     ~^^
         |   File "<stdin>", line 2, in f
         |     raise OSError('operation failed')
         | OSError: operation failed
         | Happened in Iteration 3
         +------------------------------------
     >>>


File: python.info,  Node: Classes,  Next: Brief tour of the standard library,  Prev: Errors and Exceptions,  Up: The Python Tutorial

2.9 Classes
===========

Classes provide a means of bundling data and functionality together.
Creating a new class creates a new 'type' of object, allowing new
'instances' of that type to be made.  Each class instance can have
attributes attached to it for maintaining its state.  Class instances
can also have methods (defined by its class) for modifying its state.

Compared with other programming languages, Python’s class mechanism adds
classes with a minimum of new syntax and semantics.  It is a mixture of
the class mechanisms found in C++ and Modula-3.  Python classes provide
all the standard features of Object Oriented Programming: the class
inheritance mechanism allows multiple base classes, a derived class can
override any methods of its base class or classes, and a method can call
the method of a base class with the same name.  Objects can contain
arbitrary amounts and kinds of data.  As is true for modules, classes
partake of the dynamic nature of Python: they are created at runtime,
and can be modified further after creation.

In C++ terminology, normally class members (including the data members)
are 'public' (except see below *note Private Variables: 1e41.), and all
member functions are 'virtual'.  As in Modula-3, there are no shorthands
for referencing the object’s members from its methods: the method
function is declared with an explicit first argument representing the
object, which is provided implicitly by the call.  As in Smalltalk,
classes themselves are objects.  This provides semantics for importing
and renaming.  Unlike C++ and Modula-3, built-in types can be used as
base classes for extension by the user.  Also, like in C++, most
built-in operators with special syntax (arithmetic operators,
subscripting etc.)  can be redefined for class instances.

(Lacking universally accepted terminology to talk about classes, I will
make occasional use of Smalltalk and C++ terms.  I would use Modula-3
terms, since its object-oriented semantics are closer to those of Python
than C++, but I expect that few readers have heard of it.)

* Menu:

* A Word About Names and Objects::
* Python Scopes and Namespaces::
* A First Look at Classes::
* Random Remarks::
* Inheritance::
* Private Variables::
* Odds and Ends::
* Iterators::
* Generators::
* Generator Expressions::


File: python.info,  Node: A Word About Names and Objects,  Next: Python Scopes and Namespaces,  Up: Classes

2.9.1 A Word About Names and Objects
------------------------------------

Objects have individuality, and multiple names (in multiple scopes) can
be bound to the same object.  This is known as aliasing in other
languages.  This is usually not appreciated on a first glance at Python,
and can be safely ignored when dealing with immutable basic types
(numbers, strings, tuples).  However, aliasing has a possibly surprising
effect on the semantics of Python code involving mutable objects such as
lists, dictionaries, and most other types.  This is usually used to the
benefit of the program, since aliases behave like pointers in some
respects.  For example, passing an object is cheap since only a pointer
is passed by the implementation; and if a function modifies an object
passed as an argument, the caller will see the change — this eliminates
the need for two different argument passing mechanisms as in Pascal.


File: python.info,  Node: Python Scopes and Namespaces,  Next: A First Look at Classes,  Prev: A Word About Names and Objects,  Up: Classes

2.9.2 Python Scopes and Namespaces
----------------------------------

Before introducing classes, I first have to tell you something about
Python’s scope rules.  Class definitions play some neat tricks with
namespaces, and you need to know how scopes and namespaces work to fully
understand what’s going on.  Incidentally, knowledge about this subject
is useful for any advanced Python programmer.

Let’s begin with some definitions.

A 'namespace' is a mapping from names to objects.  Most namespaces are
currently implemented as Python dictionaries, but that’s normally not
noticeable in any way (except for performance), and it may change in the
future.  Examples of namespaces are: the set of built-in names
(containing functions such as *note abs(): 1e45, and built-in exception
names); the global names in a module; and the local names in a function
invocation.  In a sense the set of attributes of an object also form a
namespace.  The important thing to know about namespaces is that there
is absolutely no relation between names in different namespaces; for
instance, two different modules may both define a function ‘maximize’
without confusion — users of the modules must prefix it with the module
name.

By the way, I use the word 'attribute' for any name following a dot —
for example, in the expression ‘z.real’, ‘real’ is an attribute of the
object ‘z’.  Strictly speaking, references to names in modules are
attribute references: in the expression ‘modname.funcname’, ‘modname’ is
a module object and ‘funcname’ is an attribute of it.  In this case
there happens to be a straightforward mapping between the module’s
attributes and the global names defined in the module: they share the
same namespace!  (1)

Attributes may be read-only or writable.  In the latter case, assignment
to attributes is possible.  Module attributes are writable: you can
write ‘modname.the_answer = 42’.  Writable attributes may also be
deleted with the *note del: 18c2. statement.  For example, ‘del
modname.the_answer’ will remove the attribute ‘the_answer’ from the
object named by ‘modname’.

Namespaces are created at different moments and have different
lifetimes.  The namespace containing the built-in names is created when
the Python interpreter starts up, and is never deleted.  The global
namespace for a module is created when the module definition is read in;
normally, module namespaces also last until the interpreter quits.  The
statements executed by the top-level invocation of the interpreter,
either read from a script file or interactively, are considered part of
a module called *note __main__: 1, so they have their own global
namespace.  (The built-in names actually also live in a module; this is
called *note builtins: 12.)

The local namespace for a function is created when the function is
called, and deleted when the function returns or raises an exception
that is not handled within the function.  (Actually, forgetting would be
a better way to describe what actually happens.)  Of course, recursive
invocations each have their own local namespace.

A 'scope' is a textual region of a Python program where a namespace is
directly accessible.  “Directly accessible” here means that an
unqualified reference to a name attempts to find the name in the
namespace.

Although scopes are determined statically, they are used dynamically.
At any time during execution, there are 3 or 4 nested scopes whose
namespaces are directly accessible:

   * the innermost scope, which is searched first, contains the local
     names

   * the scopes of any enclosing functions, which are searched starting
     with the nearest enclosing scope, contain non-local, but also
     non-global names

   * the next-to-last scope contains the current module’s global names

   * the outermost scope (searched last) is the namespace containing
     built-in names

If a name is declared global, then all references and assignments go
directly to the next-to-last scope containing the module’s global names.
To rebind variables found outside of the innermost scope, the *note
nonlocal: 12ef. statement can be used; if not declared nonlocal, those
variables are read-only (an attempt to write to such a variable will
simply create a 'new' local variable in the innermost scope, leaving the
identically named outer variable unchanged).

Usually, the local scope references the local names of the (textually)
current function.  Outside functions, the local scope references the
same namespace as the global scope: the module’s namespace.  Class
definitions place yet another namespace in the local scope.

It is important to realize that scopes are determined textually: the
global scope of a function defined in a module is that module’s
namespace, no matter from where or by what alias the function is called.
On the other hand, the actual search for names is done dynamically, at
run time — however, the language definition is evolving towards static
name resolution, at “compile” time, so don’t rely on dynamic name
resolution!  (In fact, local variables are already determined
statically.)

A special quirk of Python is that – if no *note global: 18a. or *note
nonlocal: 12ef. statement is in effect – assignments to names always go
into the innermost scope.  Assignments do not copy data — they just bind
names to objects.  The same is true for deletions: the statement ‘del x’
removes the binding of ‘x’ from the namespace referenced by the local
scope.  In fact, all operations that introduce new names use the local
scope: in particular, *note import: 5e5. statements and function
definitions bind the module or function name in the local scope.

The *note global: 18a. statement can be used to indicate that particular
variables live in the global scope and should be rebound there; the
*note nonlocal: 12ef. statement indicates that particular variables live
in an enclosing scope and should be rebound there.

* Menu:

* Scopes and Namespaces Example::

   ---------- Footnotes ----------

   (1) Except for one thing.  Module objects have a secret read-only
attribute called *note __dict__: 55e. which returns the dictionary used
to implement the module’s namespace; the name ‘__dict__’ is an attribute
but not a global name.  Obviously, using this violates the abstraction
of namespace implementation, and should be restricted to things like
post-mortem debuggers.


File: python.info,  Node: Scopes and Namespaces Example,  Up: Python Scopes and Namespaces

2.9.2.1 Scopes and Namespaces Example
.....................................

This is an example demonstrating how to reference the different scopes
and namespaces, and how *note global: 18a. and *note nonlocal: 12ef.
affect variable binding:

     def scope_test():
         def do_local():
             spam = "local spam"

         def do_nonlocal():
             nonlocal spam
             spam = "nonlocal spam"

         def do_global():
             global spam
             spam = "global spam"

         spam = "test spam"
         do_local()
         print("After local assignment:", spam)
         do_nonlocal()
         print("After nonlocal assignment:", spam)
         do_global()
         print("After global assignment:", spam)

     scope_test()
     print("In global scope:", spam)

The output of the example code is:

     After local assignment: test spam
     After nonlocal assignment: nonlocal spam
     After global assignment: nonlocal spam
     In global scope: global spam

Note how the 'local' assignment (which is default) didn’t change
'scope_test"s binding of 'spam'.  The *note nonlocal: 12ef. assignment
changed 'scope_test"s binding of 'spam', and the *note global: 18a.
assignment changed the module-level binding.

You can also see that there was no previous binding for 'spam' before
the *note global: 18a. assignment.


File: python.info,  Node: A First Look at Classes,  Next: Random Remarks,  Prev: Python Scopes and Namespaces,  Up: Classes

2.9.3 A First Look at Classes
-----------------------------

Classes introduce a little bit of new syntax, three new object types,
and some new semantics.

* Menu:

* Class Definition Syntax::
* Class Objects::
* Instance Objects::
* Method Objects::
* Class and Instance Variables::


File: python.info,  Node: Class Definition Syntax,  Next: Class Objects,  Up: A First Look at Classes

2.9.3.1 Class Definition Syntax
...............................

The simplest form of class definition looks like this:

     class ClassName:
         <statement-1>
         .
         .
         .
         <statement-N>

Class definitions, like function definitions (*note def: 14a9.
statements) must be executed before they have any effect.  (You could
conceivably place a class definition in a branch of an *note if: 2f3.
statement, or inside a function.)

In practice, the statements inside a class definition will usually be
function definitions, but other statements are allowed, and sometimes
useful — we’ll come back to this later.  The function definitions inside
a class normally have a peculiar form of argument list, dictated by the
calling conventions for methods — again, this is explained later.

When a class definition is entered, a new namespace is created, and used
as the local scope — thus, all assignments to local variables go into
this new namespace.  In particular, function definitions bind the name
of the new function here.

When a class definition is left normally (via the end), a 'class object'
is created.  This is basically a wrapper around the contents of the
namespace created by the class definition; we’ll learn more about class
objects in the next section.  The original local scope (the one in
effect just before the class definition was entered) is reinstated, and
the class object is bound here to the class name given in the class
definition header (‘ClassName’ in the example).


File: python.info,  Node: Class Objects,  Next: Instance Objects,  Prev: Class Definition Syntax,  Up: A First Look at Classes

2.9.3.2 Class Objects
.....................

Class objects support two kinds of operations: attribute references and
instantiation.

'Attribute references' use the standard syntax used for all attribute
references in Python: ‘obj.name’.  Valid attribute names are all the
names that were in the class’s namespace when the class object was
created.  So, if the class definition looked like this:

     class MyClass:
         """A simple example class"""
         i = 12345

         def f(self):
             return 'hello world'

then ‘MyClass.i’ and ‘MyClass.f’ are valid attribute references,
returning an integer and a function object, respectively.  Class
attributes can also be assigned to, so you can change the value of
‘MyClass.i’ by assignment.  *note __doc__: 1e4d. is also a valid
attribute, returning the docstring belonging to the class: ‘"A simple
example class"’.

Class 'instantiation' uses function notation.  Just pretend that the
class object is a parameterless function that returns a new instance of
the class.  For example (assuming the above class):

     x = MyClass()

creates a new 'instance' of the class and assigns this object to the
local variable ‘x’.

The instantiation operation (“calling” a class object) creates an empty
object.  Many classes like to create objects with instances customized
to a specific initial state.  Therefore a class may define a special
method named *note __init__(): 6b3, like this:

     def __init__(self):
         self.data = []

When a class defines an *note __init__(): 6b3. method, class
instantiation automatically invokes ‘__init__()’ for the newly created
class instance.  So in this example, a new, initialized instance can be
obtained by:

     x = MyClass()

Of course, the *note __init__(): 6b3. method may have arguments for
greater flexibility.  In that case, arguments given to the class
instantiation operator are passed on to ‘__init__()’.  For example,

     >>> class Complex:
     ...     def __init__(self, realpart, imagpart):
     ...         self.r = realpart
     ...         self.i = imagpart
     ...
     >>> x = Complex(3.0, -4.5)
     >>> x.r, x.i
     (3.0, -4.5)


File: python.info,  Node: Instance Objects,  Next: Method Objects,  Prev: Class Objects,  Up: A First Look at Classes

2.9.3.3 Instance Objects
........................

Now what can we do with instance objects?  The only operations
understood by instance objects are attribute references.  There are two
kinds of valid attribute names: data attributes and methods.

'data attributes' correspond to “instance variables” in Smalltalk, and
to “data members” in C++.  Data attributes need not be declared; like
local variables, they spring into existence when they are first assigned
to.  For example, if ‘x’ is the instance of ‘MyClass’ created above, the
following piece of code will print the value ‘16’, without leaving a
trace:

     x.counter = 1
     while x.counter < 10:
         x.counter = x.counter * 2
     print(x.counter)
     del x.counter

The other kind of instance attribute reference is a 'method'.  A method
is a function that “belongs to” an object.

Valid method names of an instance object depend on its class.  By
definition, all attributes of a class that are function objects define
corresponding methods of its instances.  So in our example, ‘x.f’ is a
valid method reference, since ‘MyClass.f’ is a function, but ‘x.i’ is
not, since ‘MyClass.i’ is not.  But ‘x.f’ is not the same thing as
‘MyClass.f’ — it is a 'method object', not a function object.


File: python.info,  Node: Method Objects,  Next: Class and Instance Variables,  Prev: Instance Objects,  Up: A First Look at Classes

2.9.3.4 Method Objects
......................

Usually, a method is called right after it is bound:

     x.f()

If ‘x = MyClass()’, as above, this will return the string ‘'hello
world'’.  However, it is not necessary to call a method right away:
‘x.f’ is a method object, and can be stored away and called at a later
time.  For example:

     xf = x.f
     while True:
         print(xf())

will continue to print ‘hello world’ until the end of time.

What exactly happens when a method is called?  You may have noticed that
‘x.f()’ was called without an argument above, even though the function
definition for ‘f()’ specified an argument.  What happened to the
argument?  Surely Python raises an exception when a function that
requires an argument is called without any — even if the argument isn’t
actually used…

Actually, you may have guessed the answer: the special thing about
methods is that the instance object is passed as the first argument of
the function.  In our example, the call ‘x.f()’ is exactly equivalent to
‘MyClass.f(x)’.  In general, calling a method with a list of 'n'
arguments is equivalent to calling the corresponding function with an
argument list that is created by inserting the method’s instance object
before the first argument.

In general, methods work as follows.  When a non-data attribute of an
instance is referenced, the instance’s class is searched.  If the name
denotes a valid class attribute that is a function object, references to
both the instance object and the function object are packed into a
method object.  When the method object is called with an argument list,
a new argument list is constructed from the instance object and the
argument list, and the function object is called with this new argument
list.


File: python.info,  Node: Class and Instance Variables,  Prev: Method Objects,  Up: A First Look at Classes

2.9.3.5 Class and Instance Variables
....................................

Generally speaking, instance variables are for data unique to each
instance and class variables are for attributes and methods shared by
all instances of the class:

     class Dog:

         kind = 'canine'         # class variable shared by all instances

         def __init__(self, name):
             self.name = name    # instance variable unique to each instance

     >>> d = Dog('Fido')
     >>> e = Dog('Buddy')
     >>> d.kind                  # shared by all dogs
     'canine'
     >>> e.kind                  # shared by all dogs
     'canine'
     >>> d.name                  # unique to d
     'Fido'
     >>> e.name                  # unique to e
     'Buddy'

As discussed in *note A Word About Names and Objects: 1e43, shared data
can have possibly surprising effects involving *note mutable: 1d96.
objects such as lists and dictionaries.  For example, the 'tricks' list
in the following code should not be used as a class variable because
just a single list would be shared by all 'Dog' instances:

     class Dog:

         tricks = []             # mistaken use of a class variable

         def __init__(self, name):
             self.name = name

         def add_trick(self, trick):
             self.tricks.append(trick)

     >>> d = Dog('Fido')
     >>> e = Dog('Buddy')
     >>> d.add_trick('roll over')
     >>> e.add_trick('play dead')
     >>> d.tricks                # unexpectedly shared by all dogs
     ['roll over', 'play dead']

Correct design of the class should use an instance variable instead:

     class Dog:

         def __init__(self, name):
             self.name = name
             self.tricks = []    # creates a new empty list for each dog

         def add_trick(self, trick):
             self.tricks.append(trick)

     >>> d = Dog('Fido')
     >>> e = Dog('Buddy')
     >>> d.add_trick('roll over')
     >>> e.add_trick('play dead')
     >>> d.tricks
     ['roll over']
     >>> e.tricks
     ['play dead']


File: python.info,  Node: Random Remarks,  Next: Inheritance,  Prev: A First Look at Classes,  Up: Classes

2.9.4 Random Remarks
--------------------

If the same attribute name occurs in both an instance and in a class,
then attribute lookup prioritizes the instance:

     >>> class Warehouse:
     ...    purpose = 'storage'
     ...    region = 'west'
     ...
     >>> w1 = Warehouse()
     >>> print(w1.purpose, w1.region)
     storage west
     >>> w2 = Warehouse()
     >>> w2.region = 'east'
     >>> print(w2.purpose, w2.region)
     storage east

Data attributes may be referenced by methods as well as by ordinary
users (“clients”) of an object.  In other words, classes are not usable
to implement pure abstract data types.  In fact, nothing in Python makes
it possible to enforce data hiding — it is all based upon convention.
(On the other hand, the Python implementation, written in C, can
completely hide implementation details and control access to an object
if necessary; this can be used by extensions to Python written in C.)

Clients should use data attributes with care — clients may mess up
invariants maintained by the methods by stamping on their data
attributes.  Note that clients may add data attributes of their own to
an instance object without affecting the validity of the methods, as
long as name conflicts are avoided — again, a naming convention can save
a lot of headaches here.

There is no shorthand for referencing data attributes (or other
methods!)  from within methods.  I find that this actually increases the
readability of methods: there is no chance of confusing local variables
and instance variables when glancing through a method.

Often, the first argument of a method is called ‘self’.  This is nothing
more than a convention: the name ‘self’ has absolutely no special
meaning to Python.  Note, however, that by not following the convention
your code may be less readable to other Python programmers, and it is
also conceivable that a 'class browser' program might be written that
relies upon such a convention.

Any function object that is a class attribute defines a method for
instances of that class.  It is not necessary that the function
definition is textually enclosed in the class definition: assigning a
function object to a local variable in the class is also ok.  For
example:

     # Function defined outside the class
     def f1(self, x, y):
         return min(x, x+y)

     class C:
         f = f1

         def g(self):
             return 'hello world'

         h = g

Now ‘f’, ‘g’ and ‘h’ are all attributes of class ‘C’ that refer to
function objects, and consequently they are all methods of instances of
‘C’ — ‘h’ being exactly equivalent to ‘g’.  Note that this practice
usually only serves to confuse the reader of a program.

Methods may call other methods by using method attributes of the ‘self’
argument:

     class Bag:
         def __init__(self):
             self.data = []

         def add(self, x):
             self.data.append(x)

         def addtwice(self, x):
             self.add(x)
             self.add(x)

Methods may reference global names in the same way as ordinary
functions.  The global scope associated with a method is the module
containing its definition.  (A class is never used as a global scope.)
While one rarely encounters a good reason for using global data in a
method, there are many legitimate uses of the global scope: for one
thing, functions and modules imported into the global scope can be used
by methods, as well as functions and classes defined in it.  Usually,
the class containing the method is itself defined in this global scope,
and in the next section we’ll find some good reasons why a method would
want to reference its own class.

Each value is an object, and therefore has a 'class' (also called its
'type').  It is stored as ‘object.__class__’.


File: python.info,  Node: Inheritance,  Next: Private Variables,  Prev: Random Remarks,  Up: Classes

2.9.5 Inheritance
-----------------

Of course, a language feature would not be worthy of the name “class”
without supporting inheritance.  The syntax for a derived class
definition looks like this:

     class DerivedClassName(BaseClassName):
         <statement-1>
         .
         .
         .
         <statement-N>

The name ‘BaseClassName’ must be defined in a namespace accessible from
the scope containing the derived class definition.  In place of a base
class name, other arbitrary expressions are also allowed.  This can be
useful, for example, when the base class is defined in another module:

     class DerivedClassName(modname.BaseClassName):

Execution of a derived class definition proceeds the same as for a base
class.  When the class object is constructed, the base class is
remembered.  This is used for resolving attribute references: if a
requested attribute is not found in the class, the search proceeds to
look in the base class.  This rule is applied recursively if the base
class itself is derived from some other class.

There’s nothing special about instantiation of derived classes:
‘DerivedClassName()’ creates a new instance of the class.  Method
references are resolved as follows: the corresponding class attribute is
searched, descending down the chain of base classes if necessary, and
the method reference is valid if this yields a function object.

Derived classes may override methods of their base classes.  Because
methods have no special privileges when calling other methods of the
same object, a method of a base class that calls another method defined
in the same base class may end up calling a method of a derived class
that overrides it.  (For C++ programmers: all methods in Python are
effectively ‘virtual’.)

An overriding method in a derived class may in fact want to extend
rather than simply replace the base class method of the same name.
There is a simple way to call the base class method directly: just call
‘BaseClassName.methodname(self, arguments)’.  This is occasionally
useful to clients as well.  (Note that this only works if the base class
is accessible as ‘BaseClassName’ in the global scope.)

Python has two built-in functions that work with inheritance:

   * Use *note isinstance(): 445. to check an instance’s type:
     ‘isinstance(obj, int)’ will be ‘True’ only if ‘obj.__class__’ is
     *note int: 257. or some class derived from ‘int’.

   * Use *note issubclass(): 7c5. to check class inheritance:
     ‘issubclass(bool, int)’ is ‘True’ since *note bool: 46b. is a
     subclass of *note int: 257.  However, ‘issubclass(float, int)’ is
     ‘False’ since *note float: 2f7. is not a subclass of ‘int’.

* Menu:

* Multiple Inheritance::


File: python.info,  Node: Multiple Inheritance,  Up: Inheritance

2.9.5.1 Multiple Inheritance
............................

Python supports a form of multiple inheritance as well.  A class
definition with multiple base classes looks like this:

     class DerivedClassName(Base1, Base2, Base3):
         <statement-1>
         .
         .
         .
         <statement-N>

For most purposes, in the simplest cases, you can think of the search
for attributes inherited from a parent class as depth-first,
left-to-right, not searching twice in the same class where there is an
overlap in the hierarchy.  Thus, if an attribute is not found in
‘DerivedClassName’, it is searched for in ‘Base1’, then (recursively) in
the base classes of ‘Base1’, and if it was not found there, it was
searched for in ‘Base2’, and so on.

In fact, it is slightly more complex than that; the method resolution
order changes dynamically to support cooperative calls to *note super():
4de.  This approach is known in some other multiple-inheritance
languages as call-next-method and is more powerful than the super call
found in single-inheritance languages.

Dynamic ordering is necessary because all cases of multiple inheritance
exhibit one or more diamond relationships (where at least one of the
parent classes can be accessed through multiple paths from the
bottommost class).  For example, all classes inherit from *note object:
a9b, so any case of multiple inheritance provides more than one path to
reach ‘object’.  To keep the base classes from being accessed more than
once, the dynamic algorithm linearizes the search order in a way that
preserves the left-to-right ordering specified in each class, that calls
each parent only once, and that is monotonic (meaning that a class can
be subclassed without affecting the precedence order of its parents).
Taken together, these properties make it possible to design reliable and
extensible classes with multiple inheritance.  For more detail, see
*note The Python 2.3 Method Resolution Order: 14f9.


File: python.info,  Node: Private Variables,  Next: Odds and Ends,  Prev: Inheritance,  Up: Classes

2.9.6 Private Variables
-----------------------

“Private” instance variables that cannot be accessed except from inside
an object don’t exist in Python.  However, there is a convention that is
followed by most Python code: a name prefixed with an underscore (e.g.
‘_spam’) should be treated as a non-public part of the API (whether it
is a function, a method or a data member).  It should be considered an
implementation detail and subject to change without notice.

Since there is a valid use-case for class-private members (namely to
avoid name clashes of names with names defined by subclasses), there is
limited support for such a mechanism, called 'name mangling'.  Any
identifier of the form ‘__spam’ (at least two leading underscores, at
most one trailing underscore) is textually replaced with
‘_classname__spam’, where ‘classname’ is the current class name with
leading underscore(s) stripped.  This mangling is done without regard to
the syntactic position of the identifier, as long as it occurs within
the definition of a class.

See also
........

The *note private name mangling specifications: 1e5b. for details and
special cases.

Name mangling is helpful for letting subclasses override methods without
breaking intraclass method calls.  For example:

     class Mapping:
         def __init__(self, iterable):
             self.items_list = []
             self.__update(iterable)

         def update(self, iterable):
             for item in iterable:
                 self.items_list.append(item)

         __update = update   # private copy of original update() method

     class MappingSubclass(Mapping):

         def update(self, keys, values):
             # provides new signature for update()
             # but does not break __init__()
             for item in zip(keys, values):
                 self.items_list.append(item)

The above example would work even if ‘MappingSubclass’ were to introduce
a ‘__update’ identifier since it is replaced with ‘_Mapping__update’ in
the ‘Mapping’ class and ‘_MappingSubclass__update’ in the
‘MappingSubclass’ class respectively.

Note that the mangling rules are designed mostly to avoid accidents; it
still is possible to access or modify a variable that is considered
private.  This can even be useful in special circumstances, such as in
the debugger.

Notice that code passed to ‘exec()’ or ‘eval()’ does not consider the
classname of the invoking class to be the current class; this is similar
to the effect of the ‘global’ statement, the effect of which is likewise
restricted to code that is byte-compiled together.  The same restriction
applies to ‘getattr()’, ‘setattr()’ and ‘delattr()’, as well as when
referencing ‘__dict__’ directly.


File: python.info,  Node: Odds and Ends,  Next: Iterators,  Prev: Private Variables,  Up: Classes

2.9.7 Odds and Ends
-------------------

Sometimes it is useful to have a data type similar to the Pascal
“record” or C “struct”, bundling together a few named data items.  The
idiomatic approach is to use *note dataclasses: 2f. for this purpose:

     from dataclasses import dataclass

     @dataclass
     class Employee:
         name: str
         dept: str
         salary: int

     >>> john = Employee('john', 'computer lab', 1000)
     >>> john.dept
     'computer lab'
     >>> john.salary
     1000

A piece of Python code that expects a particular abstract data type can
often be passed a class that emulates the methods of that data type
instead.  For instance, if you have a function that formats some data
from a file object, you can define a class with methods *note read():
1e24. and *note readline(): 1e5e. that get the data from a string buffer
instead, and pass it as an argument.

*note Instance method objects: 1e5f. have attributes, too: *note
m.__self__: 1415. is the instance object with the method ‘m()’, and
*note m.__func__: 1345. is the *note function object: 299. corresponding
to the method.


File: python.info,  Node: Iterators,  Next: Generators,  Prev: Odds and Ends,  Up: Classes

2.9.8 Iterators
---------------

By now you have probably noticed that most container objects can be
looped over using a *note for: 2f2. statement:

     for element in [1, 2, 3]:
         print(element)
     for element in (1, 2, 3):
         print(element)
     for key in {'one':1, 'two':2}:
         print(key)
     for char in "123":
         print(char)
     for line in open("myfile.txt"):
         print(line, end='')

This style of access is clear, concise, and convenient.  The use of
iterators pervades and unifies Python.  Behind the scenes, the *note
for: 2f2. statement calls *note iter(): 7db. on the container object.
The function returns an iterator object that defines the method *note
__next__(): 1315. which accesses elements in the container one at a
time.  When there are no more elements, ‘__next__()’ raises a *note
StopIteration: c1b. exception which tells the ‘for’ loop to terminate.
You can call the ‘__next__()’ method using the *note next(): 7dc.
built-in function; this example shows how it all works:

     >>> s = 'abc'
     >>> it = iter(s)
     >>> it
     <str_iterator object at 0x10c90e650>
     >>> next(it)
     'a'
     >>> next(it)
     'b'
     >>> next(it)
     'c'
     >>> next(it)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         next(it)
     StopIteration

Having seen the mechanics behind the iterator protocol, it is easy to
add iterator behavior to your classes.  Define an *note __iter__():
1e62. method which returns an object with a *note __next__(): 1315.
method.  If the class defines ‘__next__()’, then ‘__iter__()’ can just
return ‘self’:

     class Reverse:
         """Iterator for looping over a sequence backwards."""
         def __init__(self, data):
             self.data = data
             self.index = len(data)

         def __iter__(self):
             return self

         def __next__(self):
             if self.index == 0:
                 raise StopIteration
             self.index = self.index - 1
             return self.data[self.index]

     >>> rev = Reverse('spam')
     >>> iter(rev)
     <__main__.Reverse object at 0x00A1DB50>
     >>> for char in rev:
     ...     print(char)
     ...
     m
     a
     p
     s


File: python.info,  Node: Generators,  Next: Generator Expressions,  Prev: Iterators,  Up: Classes

2.9.9 Generators
----------------

*note Generators: 109f. are a simple and powerful tool for creating
iterators.  They are written like regular functions but use the *note
yield: 9d8. statement whenever they want to return data.  Each time
*note next(): 7dc. is called on it, the generator resumes where it left
off (it remembers all the data values and which statement was last
executed).  An example shows that generators can be trivially easy to
create:

     def reverse(data):
         for index in range(len(data)-1, -1, -1):
             yield data[index]

     >>> for char in reverse('golf'):
     ...     print(char)
     ...
     f
     l
     o
     g

Anything that can be done with generators can also be done with
class-based iterators as described in the previous section.  What makes
generators so compact is that the *note __iter__(): 1e65. and *note
__next__(): 1e66. methods are created automatically.

Another key feature is that the local variables and execution state are
automatically saved between calls.  This made the function easier to
write and much more clear than an approach using instance variables like
‘self.index’ and ‘self.data’.

In addition to automatic method creation and saving program state, when
generators terminate, they automatically raise *note StopIteration: c1b.
In combination, these features make it easy to create iterators with no
more effort than writing a regular function.


File: python.info,  Node: Generator Expressions,  Prev: Generators,  Up: Classes

2.9.10 Generator Expressions
----------------------------

Some simple generators can be coded succinctly as expressions using a
syntax similar to list comprehensions but with parentheses instead of
square brackets.  These expressions are designed for situations where
the generator is used right away by an enclosing function.  Generator
expressions are more compact but less versatile than full generator
definitions and tend to be more memory friendly than equivalent list
comprehensions.

Examples:

     >>> sum(i*i for i in range(10))                 # sum of squares
     285

     >>> xvec = [10, 20, 30]
     >>> yvec = [7, 5, 3]
     >>> sum(x*y for x,y in zip(xvec, yvec))         # dot product
     260

     >>> unique_words = set(word for line in page  for word in line.split())

     >>> valedictorian = max((student.gpa, student.name) for student in graduates)

     >>> data = 'golf'
     >>> list(data[i] for i in range(len(data)-1, -1, -1))
     ['f', 'l', 'o', 'g']


File: python.info,  Node: Brief tour of the standard library,  Next: Brief Tour of the Standard Library — Part II,  Prev: Classes,  Up: The Python Tutorial

2.10 Brief tour of the standard library
=======================================

* Menu:

* Operating system interface::
* File wildcards::
* Command-line arguments::
* Error output redirection and program termination::
* String pattern matching::
* Mathematics::
* Internet access::
* Dates and times::
* Data compression::
* Performance measurement::
* Quality control::
* Batteries included::


File: python.info,  Node: Operating system interface,  Next: File wildcards,  Up: Brief tour of the standard library

2.10.1 Operating system interface
---------------------------------

The *note os: a1. module provides dozens of functions for interacting
with the operating system:

     >>> import os
     >>> os.getcwd()      # Return the current working directory
     'C:\\Python313'
     >>> os.chdir('/server/accesslogs')   # Change current working directory
     >>> os.system('mkdir today')   # Run the command mkdir in the system shell
     0

Be sure to use the ‘import os’ style instead of ‘from os import *’.
This will keep *note os.open(): dc0. from shadowing the built-in *note
open(): 51f. function which operates much differently.

The built-in *note dir(): 635. and *note help(): 8e0. functions are
useful as interactive aids for working with large modules like *note os:
a1.:

     >>> import os
     >>> dir(os)
     <returns a list of all module functions>
     >>> help(os)
     <returns an extensive manual page created from the module's docstrings>

For daily file and directory management tasks, the *note shutil: c5.
module provides a higher level interface that is easier to use:

     >>> import shutil
     >>> shutil.copyfile('data.db', 'archive.db')
     'archive.db'
     >>> shutil.move('/build/executables', 'installdir')
     'installdir'


File: python.info,  Node: File wildcards,  Next: Command-line arguments,  Prev: Operating system interface,  Up: Brief tour of the standard library

2.10.2 File wildcards
---------------------

The *note glob: 64. module provides a function for making file lists
from directory wildcard searches:

     >>> import glob
     >>> glob.glob('*.py')
     ['primes.py', 'random.py', 'quote.py']


File: python.info,  Node: Command-line arguments,  Next: Error output redirection and program termination,  Prev: File wildcards,  Up: Brief tour of the standard library

2.10.3 Command-line arguments
-----------------------------

Common utility scripts often need to process command line arguments.
These arguments are stored in the *note sys: d9. module’s 'argv'
attribute as a list.  For instance, let’s take the following ‘demo.py’
file:

     # File demo.py
     import sys
     print(sys.argv)

Here is the output from running ‘python demo.py one two three’ at the
command line:

     ['demo.py', 'one', 'two', 'three']

The *note argparse: 6. module provides a more sophisticated mechanism to
process command line arguments.  The following script extracts one or
more filenames and an optional number of lines to be displayed:

     import argparse

     parser = argparse.ArgumentParser(
         prog='top',
         description='Show top lines from each file')
     parser.add_argument('filenames', nargs='+')
     parser.add_argument('-l', '--lines', type=int, default=10)
     args = parser.parse_args()
     print(args)

When run at the command line with ‘python top.py --lines=5 alpha.txt
beta.txt’, the script sets ‘args.lines’ to ‘5’ and ‘args.filenames’ to
‘['alpha.txt', 'beta.txt']’.


File: python.info,  Node: Error output redirection and program termination,  Next: String pattern matching,  Prev: Command-line arguments,  Up: Brief tour of the standard library

2.10.4 Error output redirection and program termination
-------------------------------------------------------

The *note sys: d9. module also has attributes for 'stdin', 'stdout', and
'stderr'.  The latter is useful for emitting warnings and error messages
to make them visible even when 'stdout' has been redirected:

     >>> sys.stderr.write('Warning, log file not found starting a new one\n')
     Warning, log file not found starting a new one

The most direct way to terminate a script is to use ‘sys.exit()’.


File: python.info,  Node: String pattern matching,  Next: Mathematics,  Prev: Error output redirection and program termination,  Up: Brief tour of the standard library

2.10.5 String pattern matching
------------------------------

The *note re: b9. module provides regular expression tools for advanced
string processing.  For complex matching and manipulation, regular
expressions offer succinct, optimized solutions:

     >>> import re
     >>> re.findall(r'\bf[a-z]*', 'which foot or hand fell fastest')
     ['foot', 'fell', 'fastest']
     >>> re.sub(r'(\b[a-z]+) \1', r'\1', 'cat in the the hat')
     'cat in the hat'

When only simple capabilities are needed, string methods are preferred
because they are easier to read and debug:

     >>> 'tea for too'.replace('too', 'two')
     'tea for two'


File: python.info,  Node: Mathematics,  Next: Internet access,  Prev: String pattern matching,  Up: Brief tour of the standard library

2.10.6 Mathematics
------------------

The *note math: 8e. module gives access to the underlying C library
functions for floating-point math:

     >>> import math
     >>> math.cos(math.pi / 4)
     0.70710678118654757
     >>> math.log(1024, 2)
     10.0

The *note random: b8. module provides tools for making random
selections:

     >>> import random
     >>> random.choice(['apple', 'pear', 'banana'])
     'apple'
     >>> random.sample(range(100), 10)   # sampling without replacement
     [30, 83, 16, 4, 8, 81, 41, 50, 18, 33]
     >>> random.random()    # random float from the interval [0.0, 1.0)
     0.17970987693706186
     >>> random.randrange(6)    # random integer chosen from range(6)
     4

The *note statistics: d2. module calculates basic statistical properties
(the mean, median, variance, etc.)  of numeric data:

     >>> import statistics
     >>> data = [2.75, 1.75, 1.25, 0.25, 0.5, 1.25, 3.5]
     >>> statistics.mean(data)
     1.6071428571428572
     >>> statistics.median(data)
     1.25
     >>> statistics.variance(data)
     1.3720238095238095

The SciPy project <‘https://scipy.org’> has many other modules for
numerical computations.


File: python.info,  Node: Internet access,  Next: Dates and times,  Prev: Mathematics,  Up: Brief tour of the standard library

2.10.7 Internet access
----------------------

There are a number of modules for accessing the internet and processing
internet protocols.  Two of the simplest are *note urllib.request: 10b.
for retrieving data from URLs and *note smtplib: ca. for sending mail:

     >>> from urllib.request import urlopen
     >>> with urlopen('https://docs.python.org/3/') as response:
     ...     for line in response:
     ...         line = line.decode()             # Convert bytes to a str
     ...         if 'updated' in line:
     ...             print(line.rstrip())         # Remove trailing newline
     ...
           Last updated on Nov 11, 2025 (20:11 UTC).

     >>> import smtplib
     >>> server = smtplib.SMTP('localhost')
     >>> server.sendmail('soothsayer@example.org', 'jcaesar@example.org',
     ... """To: jcaesar@example.org
     ... From: soothsayer@example.org
     ...
     ... Beware the Ides of March.
     ... """)
     >>> server.quit()

(Note that the second example needs a mailserver running on localhost.)


File: python.info,  Node: Dates and times,  Next: Data compression,  Prev: Internet access,  Up: Brief tour of the standard library

2.10.8 Dates and times
----------------------

The *note datetime: 30. module supplies classes for manipulating dates
and times in both simple and complex ways.  While date and time
arithmetic is supported, the focus of the implementation is on efficient
member extraction for output formatting and manipulation.  The module
also supports objects that are timezone aware.

     >>> # dates are easily constructed and formatted
     >>> import datetime as dt
     >>> now = dt.date.today()
     >>> now
     datetime.date(2003, 12, 2)
     >>> now.strftime("%m-%d-%y. %d %b %Y is a %A on the %d day of %B.")
     '12-02-03. 02 Dec 2003 is a Tuesday on the 02 day of December.'

     >>> # dates support calendar arithmetic
     >>> birthday = dt.date(1964, 7, 31)
     >>> age = now - birthday
     >>> age.days
     14368


File: python.info,  Node: Data compression,  Next: Performance measurement,  Prev: Dates and times,  Up: Brief tour of the standard library

2.10.9 Data compression
-----------------------

Common data archiving and compression formats are directly supported by
modules including: *note zlib: 133, *note gzip: 67, *note bz2: 13, *note
lzma: 8a, *note zipfile: 131. and *note tarfile: de.

     >>> import zlib
     >>> s = b'witch which has which witches wrist watch'
     >>> len(s)
     41
     >>> t = zlib.compress(s)
     >>> len(t)
     37
     >>> zlib.decompress(t)
     b'witch which has which witches wrist watch'
     >>> zlib.crc32(s)
     226805979


File: python.info,  Node: Performance measurement,  Next: Quality control,  Prev: Data compression,  Up: Brief tour of the standard library

2.10.10 Performance measurement
-------------------------------

Some Python users develop a deep interest in knowing the relative
performance of different approaches to the same problem.  Python
provides a measurement tool that answers those questions immediately.

For example, it may be tempting to use the tuple packing and unpacking
feature instead of the traditional approach to swapping arguments.  The
*note timeit: ef. module quickly demonstrates a modest performance
advantage:

     >>> from timeit import Timer
     >>> Timer('t=a; a=b; b=t', 'a=1; b=2').timeit()
     0.57535828626024577
     >>> Timer('a,b = b,a', 'a=1; b=2').timeit()
     0.54962537085770791

In contrast to *note timeit: ef.’s fine level of granularity, the *note
profile: af. and *note pstats: b0. modules provide tools for identifying
time critical sections in larger blocks of code.


File: python.info,  Node: Quality control,  Next: Batteries included,  Prev: Performance measurement,  Up: Brief tour of the standard library

2.10.11 Quality control
-----------------------

One approach for developing high quality software is to write tests for
each function as it is developed and to run those tests frequently
during the development process.

The *note doctest: 3a. module provides a tool for scanning a module and
validating tests embedded in a program’s docstrings.  Test construction
is as simple as cutting-and-pasting a typical call along with its
results into the docstring.  This improves the documentation by
providing the user with an example and it allows the doctest module to
make sure the code remains true to the documentation:

     def average(values):
         """Computes the arithmetic mean of a list of numbers.

         >>> print(average([20, 30, 70]))
         40.0
         """
         return sum(values) / len(values)

     import doctest
     doctest.testmod()   # automatically validate the embedded tests

The *note unittest: 106. module is not as effortless as the *note
doctest: 3a. module, but it allows a more comprehensive set of tests to
be maintained in a separate file:

     import unittest

     class TestStatisticalFunctions(unittest.TestCase):

         def test_average(self):
             self.assertEqual(average([20, 30, 70]), 40.0)
             self.assertEqual(round(average([1, 5, 7]), 1), 4.3)
             with self.assertRaises(ZeroDivisionError):
                 average([])
             with self.assertRaises(TypeError):
                 average(20, 30, 70)

     unittest.main()  # Calling from the command line invokes all tests


File: python.info,  Node: Batteries included,  Prev: Quality control,  Up: Brief tour of the standard library

2.10.12 Batteries included
--------------------------

Python has a “batteries included” philosophy.  This is best seen through
the sophisticated and robust capabilities of its larger packages.  For
example:

   * The *note xmlrpc.client: 12e. and *note xmlrpc.server: 12f. modules
     make implementing remote procedure calls into an almost trivial
     task.  Despite the modules’ names, no direct knowledge or handling
     of XML is needed.

   * The *note email: 3b. package is a library for managing email
     messages, including MIME and other RFC 5322(1)-based message
     documents.  Unlike *note smtplib: ca. and *note poplib: ac. which
     actually send and receive messages, the email package has a
     complete toolset for building or decoding complex message
     structures (including attachments) and for implementing internet
     encoding and header protocols.

   * The *note json: 82. package provides robust support for parsing
     this popular data interchange format.  The *note csv: 29. module
     supports direct reading and writing of files in Comma-Separated
     Value format, commonly supported by databases and spreadsheets.
     XML processing is supported by the *note xml.etree.ElementTree:
     125, *note xml.dom: 121. and *note xml.sax: 129. packages.
     Together, these modules and packages greatly simplify data
     interchange between Python applications and other tools.

   * The *note sqlite3: cf. module is a wrapper for the SQLite database
     library, providing a persistent database that can be updated and
     accessed using slightly nonstandard SQL syntax.

   * Internationalization is supported by a number of modules including
     *note gettext: 63, *note locale: 86, and the *note codecs: 1b.
     package.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: Brief Tour of the Standard Library — Part II,  Next: Virtual Environments and Packages,  Prev: Brief tour of the standard library,  Up: The Python Tutorial

2.11 Brief Tour of the Standard Library — Part II
=================================================

This second tour covers more advanced modules that support professional
programming needs.  These modules rarely occur in small scripts.

* Menu:

* Output Formatting::
* Templating::
* Working with Binary Data Record Layouts::
* Multi-threading: Multi-threading<2>.
* Logging::
* Weak References::
* Tools for Working with Lists::
* Decimal Floating-Point Arithmetic::


File: python.info,  Node: Output Formatting,  Next: Templating,  Up: Brief Tour of the Standard Library — Part II

2.11.1 Output Formatting
------------------------

The *note reprlib: bb. module provides a version of *note repr(): 803.
customized for abbreviated displays of large or deeply nested
containers:

     >>> import reprlib
     >>> reprlib.repr(set('supercalifragilisticexpialidocious'))
     "{'a', 'c', 'd', 'e', 'f', 'g', ...}"

The *note pprint: ae. module offers more sophisticated control over
printing both built-in and user defined objects in a way that is
readable by the interpreter.  When the result is longer than one line,
the “pretty printer” adds line breaks and indentation to more clearly
reveal data structure:

     >>> import pprint
     >>> t = [[[['black', 'cyan'], 'white', ['green', 'red']], [['magenta',
     ...     'yellow'], 'blue']]]
     ...
     >>> pprint.pprint(t, width=30)
     [[[['black', 'cyan'],
        'white',
        ['green', 'red']],
       [['magenta', 'yellow'],
        'blue']]]

The *note textwrap: ec. module formats paragraphs of text to fit a given
screen width:

     >>> import textwrap
     >>> doc = """The wrap() method is just like fill() except that it returns
     ... a list of strings instead of one big string with newlines to separate
     ... the wrapped lines."""
     ...
     >>> print(textwrap.fill(doc, width=40))
     The wrap() method is just like fill()
     except that it returns a list of strings
     instead of one big string with newlines
     to separate the wrapped lines.

The *note locale: 86. module accesses a database of culture specific
data formats.  The grouping attribute of locale’s format function
provides a direct way of formatting numbers with group separators:

     >>> import locale
     >>> locale.setlocale(locale.LC_ALL, 'English_United States.1252')
     'English_United States.1252'
     >>> conv = locale.localeconv()          # get a mapping of conventions
     >>> x = 1234567.8
     >>> locale.format_string("%d", x, grouping=True)
     '1,234,567'
     >>> locale.format_string("%s%.*f", (conv['currency_symbol'],
     ...                      conv['frac_digits'], x), grouping=True)
     '$1,234,567.80'


File: python.info,  Node: Templating,  Next: Working with Binary Data Record Layouts,  Prev: Output Formatting,  Up: Brief Tour of the Standard Library — Part II

2.11.2 Templating
-----------------

The *note string: d3. module includes a versatile *note Template: 68a.
class with a simplified syntax suitable for editing by end-users.  This
allows users to customize their applications without having to alter the
application.

The format uses placeholder names formed by ‘$’ with valid Python
identifiers (alphanumeric characters and underscores).  Surrounding the
placeholder with braces allows it to be followed by more alphanumeric
letters with no intervening spaces.  Writing ‘$$’ creates a single
escaped ‘$’:

     >>> from string import Template
     >>> t = Template('${village}folk send $$10 to $cause.')
     >>> t.substitute(village='Nottingham', cause='the ditch fund')
     'Nottinghamfolk send $10 to the ditch fund.'

The *note substitute(): 1e8d. method raises a *note KeyError: 345. when
a placeholder is not supplied in a dictionary or a keyword argument.
For mail-merge style applications, user supplied data may be incomplete
and the *note safe_substitute(): 1e8e. method may be more appropriate —
it will leave placeholders unchanged if data is missing:

     >>> t = Template('Return the $item to $owner.')
     >>> d = dict(item='unladen swallow')
     >>> t.substitute(d)
     Traceback (most recent call last):
       ...
     KeyError: 'owner'
     >>> t.safe_substitute(d)
     'Return the unladen swallow to $owner.'

Template subclasses can specify a custom delimiter.  For example, a
batch renaming utility for a photo browser may elect to use percent
signs for placeholders such as the current date, image sequence number,
or file format:

     >>> import time, os.path
     >>> photofiles = ['img_1074.jpg', 'img_1076.jpg', 'img_1077.jpg']
     >>> class BatchRename(Template):
     ...     delimiter = '%'
     ...
     >>> fmt = input('Enter rename style (%d-date %n-seqnum %f-format):  ')
     Enter rename style (%d-date %n-seqnum %f-format):  Ashley_%n%f

     >>> t = BatchRename(fmt)
     >>> date = time.strftime('%d%b%y')
     >>> for i, filename in enumerate(photofiles):
     ...     base, ext = os.path.splitext(filename)
     ...     newname = t.substitute(d=date, n=i, f=ext)
     ...     print('{0} --> {1}'.format(filename, newname))

     img_1074.jpg --> Ashley_0.jpg
     img_1076.jpg --> Ashley_1.jpg
     img_1077.jpg --> Ashley_2.jpg

Another application for templating is separating program logic from the
details of multiple output formats.  This makes it possible to
substitute custom templates for XML files, plain text reports, and HTML
web reports.


File: python.info,  Node: Working with Binary Data Record Layouts,  Next: Multi-threading<2>,  Prev: Templating,  Up: Brief Tour of the Standard Library — Part II

2.11.3 Working with Binary Data Record Layouts
----------------------------------------------

The *note struct: d5. module provides *note pack(): 12bd. and *note
unpack(): 18f6. functions for working with variable length binary record
formats.  The following example shows how to loop through header
information in a ZIP file without using the *note zipfile: 131. module.
Pack codes ‘"H"’ and ‘"I"’ represent two and four byte unsigned numbers
respectively.  The ‘"<"’ indicates that they are standard size and in
little-endian byte order:

     import struct

     with open('myfile.zip', 'rb') as f:
         data = f.read()

     start = 0
     for i in range(3):                      # show the first 3 file headers
         start += 14
         fields = struct.unpack('<IIIHH', data[start:start+16])
         crc32, comp_size, uncomp_size, filenamesize, extra_size = fields

         start += 16
         filename = data[start:start+filenamesize]
         start += filenamesize
         extra = data[start:start+extra_size]
         print(filename, hex(crc32), comp_size, uncomp_size)

         start += extra_size + comp_size     # skip to the next header


File: python.info,  Node: Multi-threading<2>,  Next: Logging,  Prev: Working with Binary Data Record Layouts,  Up: Brief Tour of the Standard Library — Part II

2.11.4 Multi-threading
----------------------

Threading is a technique for decoupling tasks which are not sequentially
dependent.  Threads can be used to improve the responsiveness of
applications that accept user input while other tasks run in the
background.  A related use case is running I/O in parallel with
computations in another thread.

The following code shows how the high level *note threading: ed. module
can run tasks in background while the main program continues to run:

     import threading, zipfile

     class AsyncZip(threading.Thread):
         def __init__(self, infile, outfile):
             threading.Thread.__init__(self)
             self.infile = infile
             self.outfile = outfile

         def run(self):
             f = zipfile.ZipFile(self.outfile, 'w', zipfile.ZIP_DEFLATED)
             f.write(self.infile)
             f.close()
             print('Finished background zip of:', self.infile)

     background = AsyncZip('mydata.txt', 'myarchive.zip')
     background.start()
     print('The main program continues to run in foreground.')

     background.join()    # Wait for the background task to finish
     print('Main program waited until background was done.')

The principal challenge of multi-threaded applications is coordinating
threads that share data or other resources.  To that end, the threading
module provides a number of synchronization primitives including locks,
events, condition variables, and semaphores.

While those tools are powerful, minor design errors can result in
problems that are difficult to reproduce.  So, the preferred approach to
task coordination is to concentrate all access to a resource in a single
thread and then use the *note queue: b6. module to feed that thread with
requests from other threads.  Applications using *note Queue: 13e1.
objects for inter-thread communication and coordination are easier to
design, more readable, and more reliable.


File: python.info,  Node: Logging,  Next: Weak References,  Prev: Multi-threading<2>,  Up: Brief Tour of the Standard Library — Part II

2.11.5 Logging
--------------

The *note logging: 87. module offers a full featured and flexible
logging system.  At its simplest, log messages are sent to a file or to
‘sys.stderr’:

     import logging
     logging.debug('Debugging information')
     logging.info('Informational message')
     logging.warning('Warning:config file %s not found', 'server.conf')
     logging.error('Error occurred')
     logging.critical('Critical error -- shutting down')

This produces the following output:

     WARNING:root:Warning:config file server.conf not found
     ERROR:root:Error occurred
     CRITICAL:root:Critical error -- shutting down

By default, informational and debugging messages are suppressed and the
output is sent to standard error.  Other output options include routing
messages through email, datagrams, sockets, or to an HTTP Server.  New
filters can select different routing based on message priority: *note
DEBUG: 1e95, *note INFO: 1e96, *note WARNING: 1e97, *note ERROR: 1e98,
and *note CRITICAL: 1e99.

The logging system can be configured directly from Python or can be
loaded from a user editable configuration file for customized logging
without altering the application.


File: python.info,  Node: Weak References,  Next: Tools for Working with Lists,  Prev: Logging,  Up: Brief Tour of the Standard Library — Part II

2.11.6 Weak References
----------------------

Python does automatic memory management (reference counting for most
objects and *note garbage collection: 1a83. to eliminate cycles).  The
memory is freed shortly after the last reference to it has been
eliminated.

This approach works fine for most applications but occasionally there is
a need to track objects only as long as they are being used by something
else.  Unfortunately, just tracking them creates a reference that makes
them permanent.  The *note weakref: 114. module provides tools for
tracking objects without creating a reference.  When the object is no
longer needed, it is automatically removed from a weakref table and a
callback is triggered for weakref objects.  Typical applications include
caching objects that are expensive to create:

     >>> import weakref, gc
     >>> class A:
     ...     def __init__(self, value):
     ...         self.value = value
     ...     def __repr__(self):
     ...         return str(self.value)
     ...
     >>> a = A(10)                   # create a reference
     >>> d = weakref.WeakValueDictionary()
     >>> d['primary'] = a            # does not create a reference
     >>> d['primary']                # fetch the object if it is still alive
     10
     >>> del a                       # remove the one reference
     >>> gc.collect()                # run garbage collection right away
     0
     >>> d['primary']                # entry was automatically removed
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
         d['primary']                # entry was automatically removed
       File "C:/python313/lib/weakref.py", line 46, in __getitem__
         o = self.data[key]()
     KeyError: 'primary'


File: python.info,  Node: Tools for Working with Lists,  Next: Decimal Floating-Point Arithmetic,  Prev: Weak References,  Up: Brief Tour of the Standard Library — Part II

2.11.7 Tools for Working with Lists
-----------------------------------

Many data structure needs can be met with the built-in list type.
However, sometimes there is a need for alternative implementations with
different performance trade-offs.

The *note array: 7. module provides an *note array: 1a0. object that is
like a list that stores only homogeneous data and stores it more
compactly.  The following example shows an array of numbers stored as
two byte unsigned binary numbers (typecode ‘"H"’) rather than the usual
16 bytes per entry for regular lists of Python int objects:

     >>> from array import array
     >>> a = array('H', [4000, 10, 700, 22222])
     >>> sum(a)
     26932
     >>> a[1:3]
     array('H', [10, 700])

The *note collections: 1d. module provides a *note deque: 5df. object
that is like a list with faster appends and pops from the left side but
slower lookups in the middle.  These objects are well suited for
implementing queues and breadth first tree searches:

     >>> from collections import deque
     >>> d = deque(["task1", "task2", "task3"])
     >>> d.append("task4")
     >>> print("Handling", d.popleft())
     Handling task1

     unsearched = deque([starting_node])
     def breadth_first_search(unsearched):
         node = unsearched.popleft()
         for m in gen_moves(node):
             if is_goal(m):
                 return m
             unsearched.append(m)

In addition to alternative list implementations, the library also offers
other tools such as the *note bisect: 11. module with functions for
manipulating sorted lists:

     >>> import bisect
     >>> scores = [(100, 'perl'), (200, 'tcl'), (400, 'lua'), (500, 'python')]
     >>> bisect.insort(scores, (300, 'ruby'))
     >>> scores
     [(100, 'perl'), (200, 'tcl'), (300, 'ruby'), (400, 'lua'), (500, 'python')]

The *note heapq: 69. module provides functions for implementing heaps
based on regular lists.  The lowest valued entry is always kept at
position zero.  This is useful for applications which repeatedly access
the smallest element but do not want to run a full list sort:

     >>> from heapq import heapify, heappop, heappush
     >>> data = [1, 3, 5, 7, 9, 2, 4, 6, 8, 0]
     >>> heapify(data)                      # rearrange the list into heap order
     >>> heappush(data, -5)                 # add a new entry
     >>> [heappop(data) for i in range(3)]  # fetch the three smallest entries
     [-5, 0, 1]


File: python.info,  Node: Decimal Floating-Point Arithmetic,  Prev: Tools for Working with Lists,  Up: Brief Tour of the Standard Library — Part II

2.11.8 Decimal Floating-Point Arithmetic
----------------------------------------

The *note decimal: 36. module offers a *note Decimal: 29d. datatype for
decimal floating-point arithmetic.  Compared to the built-in *note
float: 2f7. implementation of binary floating point, the class is
especially helpful for

   * financial applications and other uses which require exact decimal
     representation,

   * control over precision,

   * control over rounding to meet legal or regulatory requirements,

   * tracking of significant decimal places, or

   * applications where the user expects the results to match
     calculations done by hand.

For example, calculating a 5% tax on a 70 cent phone charge gives
different results in decimal floating point and binary floating point.
The difference becomes significant if the results are rounded to the
nearest cent:

     >>> from decimal import *
     >>> round(Decimal('0.70') * Decimal('1.05'), 2)
     Decimal('0.74')
     >>> round(.70 * 1.05, 2)
     0.73

The *note Decimal: 29d. result keeps a trailing zero, automatically
inferring four place significance from multiplicands with two place
significance.  Decimal reproduces mathematics as done by hand and avoids
issues that can arise when binary floating point cannot exactly
represent decimal quantities.

Exact representation enables the *note Decimal: 29d. class to perform
modulo calculations and equality tests that are unsuitable for binary
floating point:

     >>> Decimal('1.00') % Decimal('.10')
     Decimal('0.00')
     >>> 1.00 % 0.10
     0.09999999999999995

     >>> sum([Decimal('0.1')]*10) == Decimal('1.0')
     True
     >>> 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 == 1.0
     False

The *note decimal: 36. module provides arithmetic with as much precision
as needed:

     >>> getcontext().prec = 36
     >>> Decimal(1) / Decimal(7)
     Decimal('0.142857142857142857142857142857142857')


File: python.info,  Node: Virtual Environments and Packages,  Next: What Now?,  Prev: Brief Tour of the Standard Library — Part II,  Up: The Python Tutorial

2.12 Virtual Environments and Packages
======================================

* Menu:

* Introduction: Introduction<4>.
* Creating Virtual Environments::
* Managing Packages with pip::


File: python.info,  Node: Introduction<4>,  Next: Creating Virtual Environments,  Up: Virtual Environments and Packages

2.12.1 Introduction
-------------------

Python applications will often use packages and modules that don’t come
as part of the standard library.  Applications will sometimes need a
specific version of a library, because the application may require that
a particular bug has been fixed or the application may be written using
an obsolete version of the library’s interface.

This means it may not be possible for one Python installation to meet
the requirements of every application.  If application A needs version
1.0 of a particular module but application B needs version 2.0, then the
requirements are in conflict and installing either version 1.0 or 2.0
will leave one application unable to run.

The solution for this problem is to create a *note virtual environment:
1ea5, a self-contained directory tree that contains a Python
installation for a particular version of Python, plus a number of
additional packages.

Different applications can then use different virtual environments.  To
resolve the earlier example of conflicting requirements, application A
can have its own virtual environment with version 1.0 installed while
application B has another virtual environment with version 2.0.  If
application B requires a library be upgraded to version 3.0, this will
not affect application A’s environment.


File: python.info,  Node: Creating Virtual Environments,  Next: Managing Packages with pip,  Prev: Introduction<4>,  Up: Virtual Environments and Packages

2.12.2 Creating Virtual Environments
------------------------------------

The module used to create and manage virtual environments is called
*note venv: 111.  ‘venv’ will install the Python version from which the
command was run (as reported by the *note -version: d43. option).  For
instance, executing the command with ‘python3.12’ will install version
3.12.

To create a virtual environment, decide upon a directory where you want
to place it, and run the *note venv: 111. module as a script with the
directory path:

     python -m venv tutorial-env

This will create the ‘tutorial-env’ directory if it doesn’t exist, and
also create directories inside it containing a copy of the Python
interpreter and various supporting files.

A common directory location for a virtual environment is ‘.venv’.  This
name keeps the directory typically hidden in your shell and thus out of
the way while giving it a name that explains why the directory exists.
It also prevents clashing with ‘.env’ environment variable definition
files that some tooling supports.

Once you’ve created a virtual environment, you may activate it.

On Windows, run:

     tutorial-env\Scripts\activate

On Unix or MacOS, run:

     source tutorial-env/bin/activate

(This script is written for the bash shell.  If you use the ‘csh’ or
‘fish’ shells, there are alternate ‘activate.csh’ and ‘activate.fish’
scripts you should use instead.)

Activating the virtual environment will change your shell’s prompt to
show what virtual environment you’re using, and modify the environment
so that running ‘python’ will get you that particular version and
installation of Python.  For example:

     $ source ~/envs/tutorial-env/bin/activate
     (tutorial-env) $ python
     Python 3.5.1 (default, May  6 2016, 10:59:36)
       ...
     >>> import sys
     >>> sys.path
     ['', '/usr/local/lib/python35.zip', ...,
     '~/envs/tutorial-env/lib/python3.5/site-packages']
     >>>

To deactivate a virtual environment, type:

     deactivate

into the terminal.


File: python.info,  Node: Managing Packages with pip,  Prev: Creating Virtual Environments,  Up: Virtual Environments and Packages

2.12.3 Managing Packages with pip
---------------------------------

You can install, upgrade, and remove packages using a program called
‘pip’.  By default ‘pip’ will install packages from the Python Package
Index(1).  You can browse the Python Package Index by going to it in
your web browser.

‘pip’ has a number of subcommands: “install”, “uninstall”, “freeze”,
etc.  (Consult the *note Installing Python modules: f2c. guide for
complete documentation for ‘pip’.)

You can install the latest version of a package by specifying a
package’s name:

     (tutorial-env) $ python -m pip install novas
     Collecting novas
       Downloading novas-3.1.1.3.tar.gz (136kB)
     Installing collected packages: novas
       Running setup.py install for novas
     Successfully installed novas-3.1.1.3

You can also install a specific version of a package by giving the
package name followed by ‘==’ and the version number:

     (tutorial-env) $ python -m pip install requests==2.6.0
     Collecting requests==2.6.0
       Using cached requests-2.6.0-py2.py3-none-any.whl
     Installing collected packages: requests
     Successfully installed requests-2.6.0

If you re-run this command, ‘pip’ will notice that the requested version
is already installed and do nothing.  You can supply a different version
number to get that version, or you can run ‘python -m pip install
--upgrade’ to upgrade the package to the latest version:

     (tutorial-env) $ python -m pip install --upgrade requests
     Collecting requests
     Installing collected packages: requests
       Found existing installation: requests 2.6.0
         Uninstalling requests-2.6.0:
           Successfully uninstalled requests-2.6.0
     Successfully installed requests-2.7.0

‘python -m pip uninstall’ followed by one or more package names will
remove the packages from the virtual environment.

‘python -m pip show’ will display information about a particular
package:

     (tutorial-env) $ python -m pip show requests
     ---
     Metadata-Version: 2.0
     Name: requests
     Version: 2.7.0
     Summary: Python HTTP for Humans.
     Home-page: http://python-requests.org
     Author: Kenneth Reitz
     Author-email: me@kennethreitz.com
     License: Apache 2.0
     Location: /Users/akuchling/envs/tutorial-env/lib/python3.4/site-packages
     Requires:

‘python -m pip list’ will display all of the packages installed in the
virtual environment:

     (tutorial-env) $ python -m pip list
     novas (3.1.1.3)
     numpy (1.9.2)
     pip (7.0.3)
     requests (2.7.0)
     setuptools (16.0)

‘python -m pip freeze’ will produce a similar list of the installed
packages, but the output uses the format that ‘python -m pip install’
expects.  A common convention is to put this list in a
‘requirements.txt’ file:

     (tutorial-env) $ python -m pip freeze > requirements.txt
     (tutorial-env) $ cat requirements.txt
     novas==3.1.1.3
     numpy==1.9.2
     requests==2.7.0

The ‘requirements.txt’ can then be committed to version control and
shipped as part of an application.  Users can then install all the
necessary packages with ‘install -r’:

     (tutorial-env) $ python -m pip install -r requirements.txt
     Collecting novas==3.1.1.3 (from -r requirements.txt (line 1))
       ...
     Collecting numpy==1.9.2 (from -r requirements.txt (line 2))
       ...
     Collecting requests==2.7.0 (from -r requirements.txt (line 3))
       ...
     Installing collected packages: novas, numpy, requests
       Running setup.py install for novas
     Successfully installed novas-3.1.1.3 numpy-1.9.2 requests-2.7.0

‘pip’ has many more options.  Consult the *note Installing Python
modules: f2c. guide for complete documentation for ‘pip’.  When you’ve
written a package and want to make it available on the Python Package
Index, consult the Python packaging user guide(2).

   ---------- Footnotes ----------

   (1) https://pypi.org

   (2) 
https://packaging.python.org/en/latest/tutorials/packaging-projects/


File: python.info,  Node: What Now?,  Next: Interactive Input Editing and History Substitution,  Prev: Virtual Environments and Packages,  Up: The Python Tutorial

2.13 What Now?
==============

Reading this tutorial has probably reinforced your interest in using
Python — you should be eager to apply Python to solving your real-world
problems.  Where should you go to learn more?

This tutorial is part of Python’s documentation set.  Some other
documents in the set are:

   * *note The Python Standard Library: 144.:

     You should browse through this manual, which gives complete (though
     terse) reference material about types, functions, and the modules
     in the standard library.  The standard Python distribution includes
     a 'lot' of additional code.  There are modules to read Unix
     mailboxes, retrieve documents via HTTP, generate random numbers,
     parse command-line options, compress data, and many other tasks.
     Skimming through the Library Reference will give you an idea of
     what’s available.

   * *note Installing Python modules: f2c. explains how to install
     additional modules written by other Python users.

   * *note The Python Language Reference: 145.: A detailed explanation
     of Python’s syntax and semantics.  It’s heavy reading, but is
     useful as a complete guide to the language itself.

More Python resources:

   * ‘https://www.python.org’: The major Python website.  It contains
     code, documentation, and pointers to Python-related pages around
     the web.

   * ‘https://docs.python.org’: Fast access to Python’s documentation.

   * ‘https://pypi.org’: The Python Package Index, previously also
     nicknamed the Cheese Shop (1), is an index of user-created Python
     modules that are available for download.  Once you begin releasing
     code, you can register it here so that others can find it.

   * ‘https://code.activestate.com/recipes/langs/python/’: The Python
     Cookbook is a sizable collection of code examples, larger modules,
     and useful scripts.  Particularly notable contributions are
     collected in a book also titled Python Cookbook (O’Reilly &
     Associates, ISBN 0-596-00797-3.)

   * ‘https://pyvideo.org’ collects links to Python-related videos from
     conferences and user-group meetings.

   * ‘https://scipy.org’: The Scientific Python project includes modules
     for fast array computations and manipulations plus a host of
     packages for such things as linear algebra, Fourier transforms,
     non-linear solvers, random number distributions, statistical
     analysis and the like.

For Python-related questions and problem reports, you can post to the
newsgroup ‘comp.lang.python’, or send them to the mailing list at
<python-list@python.org>.  The newsgroup and mailing list are gatewayed,
so messages posted to one will automatically be forwarded to the other.
There are hundreds of postings a day, asking (and answering) questions,
suggesting new features, and announcing new modules.  Mailing list
archives are available at ‘https://mail.python.org/pipermail/’.

Before posting, be sure to check the list of *note Frequently Asked
Questions: 1eac. (also called the FAQ). The FAQ answers many of the
questions that come up again and again, and may already contain the
solution for your problem.

   ---------- Footnotes ----------

   (1) “Cheese Shop” is a Monty Python sketch: a customer enters a
cheese shop, but whatever cheese he asks for, the clerk says it’s
missing.


File: python.info,  Node: Interactive Input Editing and History Substitution,  Next: Floating-Point Arithmetic Issues and Limitations,  Prev: What Now?,  Up: The Python Tutorial

2.14 Interactive Input Editing and History Substitution
=======================================================

Some versions of the Python interpreter support editing of the current
input line and history substitution, similar to facilities found in the
Korn shell and the GNU Bash shell.  This is implemented using the GNU
Readline(1) library, which supports various styles of editing.  This
library has its own documentation which we won’t duplicate here.

* Menu:

* Tab Completion and History Editing::
* Alternatives to the Interactive Interpreter::

   ---------- Footnotes ----------

   (1) https://tiswww.case.edu/php/chet/readline/rltop.html


File: python.info,  Node: Tab Completion and History Editing,  Next: Alternatives to the Interactive Interpreter,  Up: Interactive Input Editing and History Substitution

2.14.1 Tab Completion and History Editing
-----------------------------------------

Completion of variable and module names is *note automatically enabled:
1004. at interpreter startup so that the ‘Tab’ key invokes the
completion function; it looks at Python statement names, the current
local variables, and the available module names.  For dotted expressions
such as ‘string.a’, it will evaluate the expression up to the final
‘'.'’ and then suggest completions from the attributes of the resulting
object.  Note that this may execute application-defined code if an
object with a *note __getattr__(): 4d6. method is part of the
expression.  The default configuration also saves your history into a
file named ‘.python_history’ in your user directory.  The history will
be available again during the next interactive interpreter session.


File: python.info,  Node: Alternatives to the Interactive Interpreter,  Prev: Tab Completion and History Editing,  Up: Interactive Input Editing and History Substitution

2.14.2 Alternatives to the Interactive Interpreter
--------------------------------------------------

This facility is an enormous step forward compared to earlier versions
of the interpreter; however, some wishes are left: It would be nice if
the proper indentation were suggested on continuation lines (the parser
knows if an *note INDENT: 1eb4. token is required next).  The completion
mechanism might use the interpreter’s symbol table.  A command to check
(or even suggest) matching parentheses, quotes, etc., would also be
useful.

One alternative enhanced interactive interpreter that has been around
for quite some time is IPython(1), which features tab completion, object
exploration and advanced history management.  It can also be thoroughly
customized and embedded into other applications.  Another similar
enhanced interactive environment is bpython(2).

   ---------- Footnotes ----------

   (1) https://ipython.org/

   (2) https://bpython-interpreter.org/


File: python.info,  Node: Floating-Point Arithmetic Issues and Limitations,  Next: Appendix,  Prev: Interactive Input Editing and History Substitution,  Up: The Python Tutorial

2.15 Floating-Point Arithmetic: Issues and Limitations
======================================================

Floating-point numbers are represented in computer hardware as base 2
(binary) fractions.  For example, the 'decimal' fraction ‘0.625’ has
value 6/10 + 2/100 + 5/1000, and in the same way the 'binary' fraction
‘0.101’ has value 1/2 + 0/4 + 1/8.  These two fractions have identical
values, the only real difference being that the first is written in base
10 fractional notation, and the second in base 2.

Unfortunately, most decimal fractions cannot be represented exactly as
binary fractions.  A consequence is that, in general, the decimal
floating-point numbers you enter are only approximated by the binary
floating-point numbers actually stored in the machine.

The problem is easier to understand at first in base 10.  Consider the
fraction 1/3.  You can approximate that as a base 10 fraction:

     0.3

or, better,

     0.33

or, better,

     0.333

and so on.  No matter how many digits you’re willing to write down, the
result will never be exactly 1/3, but will be an increasingly better
approximation of 1/3.

In the same way, no matter how many base 2 digits you’re willing to use,
the decimal value 0.1 cannot be represented exactly as a base 2
fraction.  In base 2, 1/10 is the infinitely repeating fraction

     0.0001100110011001100110011001100110011001100110011...

Stop at any finite number of bits, and you get an approximation.  On
most machines today, floats are approximated using a binary fraction
with the numerator using the first 53 bits starting with the most
significant bit and with the denominator as a power of two.  In the case
of 1/10, the binary fraction is ‘3602879701896397 / 2 ** 55’ which is
close to but not exactly equal to the true value of 1/10.

Many users are not aware of the approximation because of the way values
are displayed.  Python only prints a decimal approximation to the true
decimal value of the binary approximation stored by the machine.  On
most machines, if Python were to print the true decimal value of the
binary approximation stored for 0.1, it would have to display:

     >>> 0.1
     0.1000000000000000055511151231257827021181583404541015625

That is more digits than most people find useful, so Python keeps the
number of digits manageable by displaying a rounded value instead:

     >>> 1 / 10
     0.1

Just remember, even though the printed result looks like the exact value
of 1/10, the actual stored value is the nearest representable binary
fraction.

Interestingly, there are many different decimal numbers that share the
same nearest approximate binary fraction.  For example, the numbers
‘0.1’ and ‘0.10000000000000001’ and
‘0.1000000000000000055511151231257827021181583404541015625’ are all
approximated by ‘3602879701896397 / 2 ** 55’.  Since all of these
decimal values share the same approximation, any one of them could be
displayed while still preserving the invariant ‘eval(repr(x)) == x’.

Historically, the Python prompt and built-in *note repr(): 803. function
would choose the one with 17 significant digits, ‘0.10000000000000001’.
Starting with Python 3.1, Python (on most systems) is now able to choose
the shortest of these and simply display ‘0.1’.

Note that this is in the very nature of binary floating point: this is
not a bug in Python, and it is not a bug in your code either.  You’ll
see the same kind of thing in all languages that support your hardware’s
floating-point arithmetic (although some languages may not 'display' the
difference by default, or in all output modes).

For more pleasant output, you may wish to use string formatting to
produce a limited number of significant digits:

     >>> format(math.pi, '.12g')  # give 12 significant digits
     '3.14159265359'

     >>> format(math.pi, '.2f')   # give 2 digits after the point
     '3.14'

     >>> repr(math.pi)
     '3.141592653589793'

It’s important to realize that this is, in a real sense, an illusion:
you’re simply rounding the 'display' of the true machine value.

One illusion may beget another.  For example, since 0.1 is not exactly
1/10, summing three values of 0.1 may not yield exactly 0.3, either:

     >>> 0.1 + 0.1 + 0.1 == 0.3
     False

Also, since the 0.1 cannot get any closer to the exact value of 1/10 and
0.3 cannot get any closer to the exact value of 3/10, then pre-rounding
with *note round(): 1322. function cannot help:

     >>> round(0.1, 1) + round(0.1, 1) + round(0.1, 1) == round(0.3, 1)
     False

Though the numbers cannot be made closer to their intended exact values,
the *note math.isclose(): dde. function can be useful for comparing
inexact values:

     >>> math.isclose(0.1 + 0.1 + 0.1, 0.3)
     True

Alternatively, the *note round(): 1322. function can be used to compare
rough approximations:

     >>> round(math.pi, ndigits=2) == round(22 / 7, ndigits=2)
     True

Binary floating-point arithmetic holds many surprises like this.  The
problem with “0.1” is explained in precise detail below, in the
“Representation Error” section.  See Examples of Floating Point
Problems(1) for a pleasant summary of how binary floating point works
and the kinds of problems commonly encountered in practice.  Also see
The Perils of Floating Point(2) for a more complete account of other
common surprises.

As that says near the end, “there are no easy answers.” Still, don’t be
unduly wary of floating point!  The errors in Python float operations
are inherited from the floating-point hardware, and on most machines are
on the order of no more than 1 part in 2**53 per operation.  That’s more
than adequate for most tasks, but you do need to keep in mind that it’s
not decimal arithmetic and that every float operation can suffer a new
rounding error.

While pathological cases do exist, for most casual use of floating-point
arithmetic you’ll see the result you expect in the end if you simply
round the display of your final results to the number of decimal digits
you expect.  *note str(): 44f. usually suffices, and for finer control
see the *note str.format(): 624. method’s format specifiers in *note
Format string syntax: 13e8.

For use cases which require exact decimal representation, try using the
*note decimal: 36. module which implements decimal arithmetic suitable
for accounting applications and high-precision applications.

Another form of exact arithmetic is supported by the *note fractions:
5d. module which implements arithmetic based on rational numbers (so the
numbers like 1/3 can be represented exactly).

If you are a heavy user of floating-point operations you should take a
look at the NumPy package and many other packages for mathematical and
statistical operations supplied by the SciPy project.  See
<‘https://scipy.org’>.

Python provides tools that may help on those rare occasions when you
really 'do' want to know the exact value of a float.  The *note
float.as_integer_ratio(): 1eb9. method expresses the value of a float as
a fraction:

     >>> x = 3.14159
     >>> x.as_integer_ratio()
     (3537115888337719, 1125899906842624)

Since the ratio is exact, it can be used to losslessly recreate the
original value:

     >>> x == 3537115888337719 / 1125899906842624
     True

The *note float.hex(): 1eba. method expresses a float in hexadecimal
(base 16), again giving the exact value stored by your computer:

     >>> x.hex()
     '0x1.921f9f01b866ep+1'

This precise hexadecimal representation can be used to reconstruct the
float value exactly:

     >>> x == float.fromhex('0x1.921f9f01b866ep+1')
     True

Since the representation is exact, it is useful for reliably porting
values across different versions of Python (platform independence) and
exchanging data with other languages that support the same format (such
as Java and C99).

Another helpful tool is the *note sum(): 46d. function which helps
mitigate loss-of-precision during summation.  It uses extended precision
for intermediate rounding steps as values are added onto a running
total.  That can make a difference in overall accuracy so that the
errors do not accumulate to the point where they affect the final total:

     >>> 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 == 1.0
     False
     >>> sum([0.1] * 10) == 1.0
     True

The *note math.fsum(): 1422. goes further and tracks all of the “lost
digits” as values are added onto a running total so that the result has
only a single rounding.  This is slower than *note sum(): 46d. but will
be more accurate in uncommon cases where large magnitude inputs mostly
cancel each other out leaving a final sum near zero:

     >>> arr = [-0.10430216751806065, -266310978.67179024, 143401161448607.16,
     ...        -143401161400469.7, 266262841.31058735, -0.003244936839808227]
     >>> float(sum(map(Fraction, arr)))   # Exact summation with single rounding
     8.042173697819788e-13
     >>> math.fsum(arr)                   # Single rounding
     8.042173697819788e-13
     >>> sum(arr)                         # Multiple roundings in extended precision
     8.042178034628478e-13
     >>> total = 0.0
     >>> for x in arr:
     ...     total += x                   # Multiple roundings in standard precision
     ...
     >>> total                            # Straight addition has no correct digits!
     -0.0051575902860057365

* Menu:

* Representation Error::

   ---------- Footnotes ----------

   (1) 
https://jvns.ca/blog/2023/01/13/examples-of-floating-point-problems/

   (2) http://www.indowsway.com/floatingpoint.htm


File: python.info,  Node: Representation Error,  Up: Floating-Point Arithmetic Issues and Limitations

2.15.1 Representation Error
---------------------------

This section explains the “0.1” example in detail, and shows how you can
perform an exact analysis of cases like this yourself.  Basic
familiarity with binary floating-point representation is assumed.

'Representation error' refers to the fact that some (most, actually)
decimal fractions cannot be represented exactly as binary (base 2)
fractions.  This is the chief reason why Python (or Perl, C, C++, Java,
Fortran, and many others) often won’t display the exact decimal number
you expect.

Why is that?  1/10 is not exactly representable as a binary fraction.
Since at least 2000, almost all machines use IEEE 754 binary
floating-point arithmetic, and almost all platforms map Python floats to
IEEE 754 binary64 “double precision” values.  IEEE 754 binary64 values
contain 53 bits of precision, so on input the computer strives to
convert 0.1 to the closest fraction it can of the form 'J'/2**'N' where
'J' is an integer containing exactly 53 bits.  Rewriting

     1 / 10 ~= J / (2**N)

as

     J ~= 2**N / 10

and recalling that 'J' has exactly 53 bits (is ‘>= 2**52’ but ‘<
2**53’), the best value for 'N' is 56:

     >>> 2**52 <=  2**56 // 10  < 2**53
     True

That is, 56 is the only value for 'N' that leaves 'J' with exactly 53
bits.  The best possible value for 'J' is then that quotient rounded:

     >>> q, r = divmod(2**56, 10)
     >>> r
     6

Since the remainder is more than half of 10, the best approximation is
obtained by rounding up:

     >>> q+1
     7205759403792794

Therefore the best possible approximation to 1/10 in IEEE 754 double
precision is:

     7205759403792794 / 2 ** 56

Dividing both the numerator and denominator by two reduces the fraction
to:

     3602879701896397 / 2 ** 55

Note that since we rounded up, this is actually a little bit larger than
1/10; if we had not rounded up, the quotient would have been a little
bit smaller than 1/10.  But in no case can it be 'exactly' 1/10!

So the computer never “sees” 1/10: what it sees is the exact fraction
given above, the best IEEE 754 double approximation it can get:

     >>> 0.1 * 2 ** 55
     3602879701896397.0

If we multiply that fraction by 10**55, we can see the value out to 55
decimal digits:

     >>> 3602879701896397 * 10 ** 55 // 2 ** 55
     1000000000000000055511151231257827021181583404541015625

meaning that the exact number stored in the computer is equal to the
decimal value 0.1000000000000000055511151231257827021181583404541015625.
Instead of displaying the full decimal value, many languages (including
older versions of Python), round the result to 17 significant digits:

     >>> format(0.1, '.17f')
     '0.10000000000000001'

The *note fractions: 5d. and *note decimal: 36. modules make these
calculations easy:

     >>> from decimal import Decimal
     >>> from fractions import Fraction

     >>> Fraction.from_float(0.1)
     Fraction(3602879701896397, 36028797018963968)

     >>> (0.1).as_integer_ratio()
     (3602879701896397, 36028797018963968)

     >>> Decimal.from_float(0.1)
     Decimal('0.1000000000000000055511151231257827021181583404541015625')

     >>> format(Decimal.from_float(0.1), '.17')
     '0.10000000000000001'


File: python.info,  Node: Appendix,  Prev: Floating-Point Arithmetic Issues and Limitations,  Up: The Python Tutorial

2.16 Appendix
=============

* Menu:

* Interactive Mode: Interactive Mode<2>.


File: python.info,  Node: Interactive Mode<2>,  Up: Appendix

2.16.1 Interactive Mode
-----------------------

There are two variants of the interactive *note REPL: 16a.  The classic
basic interpreter is supported on all platforms with minimal line
control capabilities.

On Windows, or Unix-like systems with *note curses: 2b. support, a new
interactive shell is used by default since Python 3.13.  This one
supports color, multiline editing, history browsing, and paste mode.  To
disable color, see *note Controlling color: 16b. for details.  Function
keys provide some additional functionality.  ‘F1’ enters the interactive
help browser *note pydoc: b5.  ‘F2’ allows for browsing command-line
history with neither output nor the *note >>>: 16c. and *note …: 16d.
prompts.  ‘F3’ enters “paste mode”, which makes pasting larger blocks of
code easier.  Press ‘F3’ to return to the regular prompt.

When using the new interactive shell, exit the shell by typing ‘exit’ or
‘quit’.  Adding call parentheses after those commands is not required.

If the new interactive shell is not desired, it can be disabled via the
*note PYTHON_BASIC_REPL: 16e. environment variable.

* Menu:

* Error Handling::
* Executable Python Scripts::
* The Interactive Startup File::
* The Customization Modules::


File: python.info,  Node: Error Handling,  Next: Executable Python Scripts,  Up: Interactive Mode<2>

2.16.1.1 Error Handling
.......................

When an error occurs, the interpreter prints an error message and a
stack trace.  In interactive mode, it then returns to the primary
prompt; when input came from a file, it exits with a nonzero exit status
after printing the stack trace.  (Exceptions handled by an *note except:
18b. clause in a *note try: 6ec. statement are not errors in this
context.)  Some errors are unconditionally fatal and cause an exit with
a nonzero exit status; this applies to internal inconsistencies and some
cases of running out of memory.  All error messages are written to the
standard error stream; normal output from executed commands is written
to standard output.

Typing the interrupt character (usually ‘Control’-‘C’ or ‘Delete’) to
the primary or secondary prompt cancels the input and returns to the
primary prompt.  (1)  Typing an interrupt while a command is executing
raises the *note KeyboardInterrupt: 9dc. exception, which may be handled
by a *note try: 6ec. statement.

   ---------- Footnotes ----------

   (1) A problem with the GNU Readline package may prevent this.


File: python.info,  Node: Executable Python Scripts,  Next: The Interactive Startup File,  Prev: Error Handling,  Up: Interactive Mode<2>

2.16.1.2 Executable Python Scripts
..................................

On BSD’ish Unix systems, Python scripts can be made directly executable,
like shell scripts, by putting the line

     #!/usr/bin/env python3

(assuming that the interpreter is on the user’s ‘PATH’) at the beginning
of the script and giving the file an executable mode.  The ‘#!’ must be
the first two characters of the file.  On some platforms, this first
line must end with a Unix-style line ending (‘'\n'’), not a Windows
(‘'\r\n'’) line ending.  Note that the hash, or pound, character, ‘'#'’,
is used to start a comment in Python.

The script can be given an executable mode, or permission, using the
‘chmod’ command.

     $ chmod +x myscript.py

On Windows systems, there is no notion of an “executable mode”.  The
Python installer automatically associates ‘.py’ files with ‘python.exe’
so that a double-click on a Python file will run it as a script.  The
extension can also be ‘.pyw’, in that case, the console window that
normally appears is suppressed.


File: python.info,  Node: The Interactive Startup File,  Next: The Customization Modules,  Prev: Executable Python Scripts,  Up: Interactive Mode<2>

2.16.1.3 The Interactive Startup File
.....................................

When you use Python interactively, it is frequently handy to have some
standard commands executed every time the interpreter is started.  You
can do this by setting an environment variable named *note
PYTHONSTARTUP: 1003. to the name of a file containing your start-up
commands.  This is similar to the ‘.profile’ feature of the Unix shells.

This file is only read in interactive sessions, not when Python reads
commands from a script, and not when ‘/dev/tty’ is given as the explicit
source of commands (which otherwise behaves like an interactive
session).  It is executed in the same namespace where interactive
commands are executed, so that objects that it defines or imports can be
used without qualification in the interactive session.  You can also
change the prompts ‘sys.ps1’ and ‘sys.ps2’ in this file.

If you want to read an additional start-up file from the current
directory, you can program this in the global start-up file using code
like ‘if os.path.isfile('.pythonrc.py'):
exec(open('.pythonrc.py').read())’.  If you want to use the startup file
in a script, you must do this explicitly in the script:

     import os
     filename = os.environ.get('PYTHONSTARTUP')
     if filename and os.path.isfile(filename):
         with open(filename) as fobj:
             startup_file = fobj.read()
         exec(startup_file)


File: python.info,  Node: The Customization Modules,  Prev: The Interactive Startup File,  Up: Interactive Mode<2>

2.16.1.4 The Customization Modules
..................................

Python provides two hooks to let you customize it: sitecustomize and
usercustomize.  To see how it works, you need first to find the location
of your user site-packages directory.  Start Python and run this code:

     >>> import site
     >>> site.getusersitepackages()
     '/home/user/.local/lib/python3.x/site-packages'

Now you can create a file named ‘usercustomize.py’ in that directory and
put anything you want in it.  It will affect every invocation of Python,
unless it is started with the *note -s: 13db. option to disable the
automatic import.

sitecustomize works in the same way, but is typically created by an
administrator of the computer in the global site-packages directory, and
is imported before usercustomize.  See the documentation of the *note
site: c7. module for more details.


File: python.info,  Node: Python Setup and Usage,  Next: The Python Language Reference,  Prev: The Python Tutorial,  Up: Top

3 Python Setup and Usage
************************

This part of the documentation is devoted to general information on the
setup of the Python environment on different platforms, the invocation
of the interpreter and things that make working with Python easier.

* Menu:

* Command line and environment::
* Using Python on Unix platforms::
* Configure Python::
* Using Python on Windows::
* Using Python on macOS::
* Using Python on Android::
* Using Python on iOS::
* Editors and IDEs::


File: python.info,  Node: Command line and environment,  Next: Using Python on Unix platforms,  Up: Python Setup and Usage

3.1 Command line and environment
================================

The CPython interpreter scans the command line and the environment for
various settings.

'CPython implementation detail:' Other implementations’ command line
schemes may differ.  See *note Alternate Implementations: 1ecf. for
further resources.

* Menu:

* Command line::
* Environment variables::


File: python.info,  Node: Command line,  Next: Environment variables,  Up: Command line and environment

3.1.1 Command line
------------------

When invoking Python, you may specify any of these options:

     python [-bBdEhiIOPqRsSuvVWx?] [-c command | -m module-name | script | - ] [args]

The most common use case is, of course, a simple invocation of a script:

     python myscript.py

* Menu:

* Interface options::
* Generic options::
* Miscellaneous options::
* Controlling color::
* Options you shouldn’t use::


File: python.info,  Node: Interface options,  Next: Generic options,  Up: Command line

3.1.1.1 Interface options
.........................

The interpreter interface resembles that of the UNIX shell, but provides
some additional methods of invocation:

   * When called with standard input connected to a tty device, it
     prompts for commands and executes them until an EOF (an end-of-file
     character, you can produce that with ‘Ctrl’-‘D’ on UNIX or
     ‘Ctrl’-‘Z,’ ‘Enter’ on Windows) is read.  For more on interactive
     mode, see *note Interactive Mode: 16f.

   * When called with a file name argument or with a file as standard
     input, it reads and executes a script from that file.

   * When called with a directory name argument, it reads and executes
     an appropriately named script from that directory.

   * When called with ‘-c command’, it executes the Python statement(s)
     given as 'command'.  Here 'command' may contain multiple statements
     separated by newlines.  Leading whitespace is significant in Python
     statements!

   * When called with ‘-m module-name’, the given module is located on
     the Python module path and executed as a script.

In non-interactive mode, the entire input is parsed before it is
executed.

An interface option terminates the list of options consumed by the
interpreter, all consecutive arguments will end up in *note sys.argv:
12ab. – note that the first element, subscript zero (‘sys.argv[0]’), is
a string reflecting the program’s source.

 -- Option: -c <command>

     Execute the Python code in 'command'.  'command' can be one or more
     statements separated by newlines, with significant leading
     whitespace as in normal module code.

     If this option is given, the first element of *note sys.argv: 12ab.
     will be ‘"-c"’ and the current directory will be added to the start
     of *note sys.path: 3b7. (allowing modules in that directory to be
     imported as top level modules).

     Raises an *note auditing event: 1a15. ‘cpython.run_command’ with
     argument ‘command’.

 -- Option: -m <module-name>

     Search *note sys.path: 3b7. for the named module and execute its
     contents as the *note __main__: 1. module.

     Since the argument is a 'module' name, you must not give a file
     extension (‘.py’).  The module name should be a valid absolute
     Python module name, but the implementation may not always enforce
     this (e.g.  it may allow you to use a name that includes a hyphen).

     Package names (including namespace packages) are also permitted.
     When a package name is supplied instead of a normal module, the
     interpreter will execute ‘<pkg>.__main__’ as the main module.  This
     behaviour is deliberately similar to the handling of directories
     and zipfiles that are passed to the interpreter as the script
     argument.

          Note: This option cannot be used with built-in modules and
          extension modules written in C, since they do not have Python
          module files.  However, it can still be used for precompiled
          modules, even if the original source file is not available.

     If this option is given, the first element of *note sys.argv: 12ab.
     will be the full path to the module file (while the module file is
     being located, the first element will be set to ‘"-m"’).  As with
     the *note -c: 5e3. option, the current directory will be added to
     the start of *note sys.path: 3b7.

     *note -I: 968. option can be used to run the script in isolated
     mode where *note sys.path: 3b7. contains neither the current
     directory nor the user’s site-packages directory.  All ‘PYTHON*’
     environment variables are ignored, too.

     Many standard library modules contain code that is invoked on their
     execution as a script.  An example is the *note timeit: ef. module:

          python -m timeit -s "setup here" "benchmarked code here"
          python -m timeit -h # for details

     Raises an *note auditing event: 1a15. ‘cpython.run_module’ with
     argument ‘module-name’.

     See also
     ........

     *note runpy.run_module(): 193d.

          Equivalent functionality directly available to Python code

     PEP 338(1) – Executing modules as scripts

     Changed in version 3.1: Supply the package name to run a ‘__main__’
     submodule.

     Changed in version 3.4: namespace packages are also supported

 -- Describe: -

     Read commands from standard input (*note sys.stdin: 540.).  If
     standard input is a terminal, *note -i: 152a. is implied.

     If this option is given, the first element of *note sys.argv: 12ab.
     will be ‘"-"’ and the current directory will be added to the start
     of *note sys.path: 3b7.

     Raises an *note auditing event: 1a15. ‘cpython.run_stdin’ with no
     arguments.

 -- Describe: <script>

     Execute the Python code contained in 'script', which must be a
     filesystem path (absolute or relative) referring to either a Python
     file, a directory containing a ‘__main__.py’ file, or a zipfile
     containing a ‘__main__.py’ file.

     If this option is given, the first element of *note sys.argv: 12ab.
     will be the script name as given on the command line.

     If the script name refers directly to a Python file, the directory
     containing that file is added to the start of *note sys.path: 3b7,
     and the file is executed as the *note __main__: 1. module.

     If the script name refers to a directory or zipfile, the script
     name is added to the start of *note sys.path: 3b7. and the
     ‘__main__.py’ file in that location is executed as the *note
     __main__: 1. module.

     *note -I: 968. option can be used to run the script in isolated
     mode where *note sys.path: 3b7. contains neither the script’s
     directory nor the user’s site-packages directory.  All ‘PYTHON*’
     environment variables are ignored, too.

     Raises an *note auditing event: 1a15. ‘cpython.run_file’ with
     argument ‘filename’.

     See also
     ........

     *note runpy.run_path(): 181.

          Equivalent functionality directly available to Python code

If no interface option is given, *note -i: 152a. is implied,
‘sys.argv[0]’ is an empty string (‘""’) and the current directory will
be added to the start of *note sys.path: 3b7.  Also, tab-completion and
history editing is automatically enabled, if available on your platform
(see *note Readline configuration: 1004.).

See also
........

*note Invoking the Interpreter: 1d79.

Changed in version 3.4: Automatic enabling of tab-completion and history
editing.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0338/


File: python.info,  Node: Generic options,  Next: Miscellaneous options,  Prev: Interface options,  Up: Command line

3.1.1.2 Generic options
.......................

 -- Option: -?
 -- Option: -h
 -- Option: --help

     Print a short description of all command line options and
     corresponding environment variables and exit.

 -- Option: --help-env

     Print a short description of Python-specific environment variables
     and exit.

     Added in version 3.11.

 -- Option: --help-xoptions

     Print a description of implementation-specific *note -X: 176.
     options and exit.

     Added in version 3.11.

 -- Option: --help-all

     Print complete usage information and exit.

     Added in version 3.11.

 -- Option: -V
 -- Option: --version

     Print the Python version number and exit.  Example output could be:

          Python 3.8.0b2+

     When given twice, print more information about the build, like:

          Python 3.8.0b2+ (3.8:0c076caaa8, Apr 20 2019, 21:55:00)
          [GCC 6.2.0 20161005]

     Added in version 3.6: The ‘-VV’ option.


File: python.info,  Node: Miscellaneous options,  Next: Controlling color,  Prev: Generic options,  Up: Command line

3.1.1.3 Miscellaneous options
.............................

 -- Option: -b

     Issue a warning when converting *note bytes: 1c2. or *note
     bytearray: 2ea. to *note str: 44f. without specifying encoding or
     comparing ‘bytes’ or ‘bytearray’ with ‘str’ or ‘bytes’ with *note
     int: 257.  Issue an error when the option is given twice (‘-bb’).

     Changed in version 3.5: Affects also comparisons of *note bytes:
     1c2. with *note int: 257.

 -- Option: -B

     If given, Python won’t try to write ‘.pyc’ files on the import of
     source modules.  See also *note PYTHONDONTWRITEBYTECODE: 141c.

 -- Option: --check-hash-based-pycs default|always|never

     Control the validation behavior of hash-based ‘.pyc’ files.  See
     *note Cached bytecode invalidation: 5ef.  When set to ‘default’,
     checked and unchecked hash-based bytecode cache files are validated
     according to their default semantics.  When set to ‘always’, all
     hash-based ‘.pyc’ files, whether checked or unchecked, are
     validated against their corresponding source file.  When set to
     ‘never’, hash-based ‘.pyc’ files are not validated against their
     corresponding source files.

     The semantics of timestamp-based ‘.pyc’ files are unaffected by
     this option.

 -- Option: -d

     Turn on parser debugging output (for expert only).  See also the
     *note PYTHONDEBUG: 1edb. environment variable.

     This option requires a *note debug build of Python: 1f9, otherwise
     it’s ignored.

 -- Option: -E

     Ignore all ‘PYTHON*’ environment variables, e.g.  *note PYTHONPATH:
     1058. and *note PYTHONHOME: 3bf, that might be set.

     See also the *note -P: 5a7. and *note -I: 968. (isolated) options.

 -- Option: -i

     Enter interactive mode after execution.

     Using the *note -i: 152a. option will enter interactive mode in any
     of the following circumstances:

        * When a script is passed as first argument

        * When the *note -c: 5e3. option is used

        * When the *note -m: 5e4. option is used

     Interactive mode will start even when *note sys.stdin: 540. does
     not appear to be a terminal.  The *note PYTHONSTARTUP: 1003. file
     is not read.

     This can be useful to inspect global variables or a stack trace
     when a script raises an exception.  See also *note PYTHONINSPECT:
     1529.

 -- Option: -I

     Run Python in isolated mode.  This also implies *note -E: 967,
     *note -P: 5a7. and *note -s: 13db. options.

     In isolated mode *note sys.path: 3b7. contains neither the script’s
     directory nor the user’s site-packages directory.  All ‘PYTHON*’
     environment variables are ignored, too.  Further restrictions may
     be imposed to prevent the user from injecting malicious code.

     Added in version 3.4.

 -- Option: -O

     Remove assert statements and any code conditional on the value of
     *note __debug__: 7de.  Augment the filename for compiled (*note
     bytecode: 187.) files by adding ‘.opt-1’ before the ‘.pyc’
     extension (see PEP 488(1)).  See also *note PYTHONOPTIMIZE: 1edc.

     Changed in version 3.5: Modify ‘.pyc’ filenames according to PEP
     488(2).

 -- Option: -OO

     Do *note -O: de3. and also discard docstrings.  Augment the
     filename for compiled (*note bytecode: 187.) files by adding
     ‘.opt-2’ before the ‘.pyc’ extension (see PEP 488(3)).

     Changed in version 3.5: Modify ‘.pyc’ filenames according to PEP
     488(4).

 -- Option: -P

     Don’t prepend a potentially unsafe path to *note sys.path: 3b7.:

        * ‘python -m module’ command line: Don’t prepend the current
          working directory.

        * ‘python script.py’ command line: Don’t prepend the script’s
          directory.  If it’s a symbolic link, resolve symbolic links.

        * ‘python -c code’ and ‘python’ (REPL) command lines: Don’t
          prepend an empty string, which means the current working
          directory.

     See also the *note PYTHONSAFEPATH: 5a8. environment variable, and
     *note -E: 967. and *note -I: 968. (isolated) options.

     Added in version 3.11.

 -- Option: -q

     Don’t display the copyright and version messages even in
     interactive mode.

     Added in version 3.2.

 -- Option: -R

     Turn on hash randomization.  This option only has an effect if the
     *note PYTHONHASHSEED: 10bb. environment variable is set to anything
     other than ‘random’, since hash randomization is enabled by
     default.

     On previous versions of Python, this option turns on hash
     randomization, so that the *note __hash__(): b14. values of str and
     bytes objects are “salted” with an unpredictable random value.
     Although they remain constant within an individual Python process,
     they are not predictable between repeated invocations of Python.

     Hash randomization is intended to provide protection against a
     denial-of-service caused by carefully chosen inputs that exploit
     the worst case performance of a dict construction, 'O'('n'^2)
     complexity.  See ‘https://ocert.org/advisories/ocert-2011-003.html’
     for details.

     *note PYTHONHASHSEED: 10bb. allows you to set a fixed value for the
     hash seed secret.

     Added in version 3.2.3.

     Changed in version 3.7: The option is no longer ignored.

 -- Option: -s

     Don’t add the *note user site-packages directory: 1edd. to *note
     sys.path: 3b7.

     See also *note PYTHONNOUSERSITE: 13dc.

     See also
     ........

     PEP 370(5) – Per user site-packages directory

 -- Option: -S

     Disable the import of the module *note site: c7. and the
     site-dependent manipulations of *note sys.path: 3b7. that it
     entails.  Also disable these manipulations if ‘site’ is explicitly
     imported later (call *note site.main(): 1ede. if you want them to
     be triggered).

 -- Option: -u

     Force the stdout and stderr streams to be unbuffered.  This option
     has no effect on the stdin stream.

     See also *note PYTHONUNBUFFERED: 1b37.

     Changed in version 3.7: The text layer of the stdout and stderr
     streams now is unbuffered.

 -- Option: -v

     Print a message each time a module is initialized, showing the
     place (filename or built-in module) from which it is loaded.  When
     given twice (‘-vv’), print a message for each file that is checked
     for when searching for a module.  Also provides information on
     module cleanup at exit.

     Changed in version 3.10: The *note site: c7. module reports the
     site-specific paths and ‘.pth’ files being processed.

     See also *note PYTHONVERBOSE: 1edf.

 -- Option: -W arg

     Warning control.  Python’s warning machinery by default prints
     warning messages to *note sys.stderr: 943.

     The simplest settings apply a particular action unconditionally to
     all warnings emitted by a process (even those that are otherwise
     ignored by default):

          -Wdefault  # Warn once per call location
          -Werror    # Convert to exceptions
          -Walways   # Warn every time
          -Wall      # Same as -Walways
          -Wmodule   # Warn once per calling module
          -Wonce     # Warn once per Python process
          -Wignore   # Never warn

     The action names can be abbreviated as desired and the interpreter
     will resolve them to the appropriate action name.  For example,
     ‘-Wi’ is the same as ‘-Wignore’.

     The full form of argument is:

          action:message:category:module:lineno

     Empty fields match all values; trailing empty fields may be
     omitted.  For example ‘-W ignore::DeprecationWarning’ ignores all
     DeprecationWarning warnings.

     The 'action' field is as explained above but only applies to
     warnings that match the remaining fields.

     The 'message' field must match the whole warning message; this
     match is case-insensitive.

     The 'category' field matches the warning category (ex:
     ‘DeprecationWarning’).  This must be a class name; the match test
     whether the actual warning category of the message is a subclass of
     the specified warning category.

     The 'module' field matches the (fully qualified) module name; this
     match is case-sensitive.

     The 'lineno' field matches the line number, where zero matches all
     line numbers and is thus equivalent to an omitted line number.

     Multiple *note -W: 8d0. options can be given; when a warning
     matches more than one option, the action for the last matching
     option is performed.  Invalid ‘-W’ options are ignored (though, a
     warning message is printed about invalid options when the first
     warning is issued).

     Warnings can also be controlled using the *note PYTHONWARNINGS:
     bc8. environment variable and from within a Python program using
     the *note warnings: 112. module.  For example, the *note
     warnings.filterwarnings(): 14f8. function can be used to use a
     regular expression on the warning message.

     See *note The Warnings Filter: 8d2. and *note Describing Warning
     Filters: 1ee1. for more details.

 -- Option: -x

     Skip the first line of the source, allowing use of non-Unix forms
     of ‘#!cmd’.  This is intended for a DOS specific hack only.

 -- Option: -X

     Reserved for various implementation-specific options.  CPython
     currently defines the following possible values:

        * ‘-X faulthandler’ to enable *note faulthandler: 58.  See also
          *note PYTHONFAULTHANDLER: 10c3.

          Added in version 3.3.

        * ‘-X showrefcount’ to output the total reference count and
          number of used memory blocks when the program finishes or
          after each statement in the interactive interpreter.  This
          only works on *note debug builds: 1f9.

          Added in version 3.4.

        * ‘-X tracemalloc’ to start tracing Python memory allocations
          using the *note tracemalloc: ff. module.  By default, only the
          most recent frame is stored in a traceback of a trace.  Use
          ‘-X tracemalloc=NFRAME’ to start tracing with a traceback
          limit of 'NFRAME' frames.  See *note tracemalloc.start():
          1ee3. and *note PYTHONTRACEMALLOC: 1ee4. for more information.

          Added in version 3.4.

        * ‘-X int_max_str_digits’ configures the *note integer string
          conversion length limitation: 5f8.  See also *note
          PYTHONINTMAXSTRDIGITS: 18dd.

          Added in version 3.11.

        * ‘-X importtime’ to show how long each import takes.  It shows
          module name, cumulative time (including nested imports) and
          self time (excluding nested imports).  Note that its output
          may be broken in multi-threaded application.  Typical usage is
          ‘python3 -X importtime -c 'import asyncio'’.  See also *note
          PYTHONPROFILEIMPORTTIME: b0e.

          Added in version 3.7.

        * ‘-X dev’: enable *note Python Development Mode: 1f8,
          introducing additional runtime checks that are too expensive
          to be enabled by default.  See also *note PYTHONDEVMODE: b06.

          Added in version 3.7.

        * ‘-X utf8’ enables the *note Python UTF-8 Mode: 659.  ‘-X
          utf8=0’ explicitly disables *note Python UTF-8 Mode: 659.
          (even when it would otherwise activate automatically).  See
          also *note PYTHONUTF8: aee.

          Added in version 3.7.

        * ‘-X pycache_prefix=PATH’ enables writing ‘.pyc’ files to a
          parallel tree rooted at the given directory instead of to the
          code tree.  See also *note PYTHONPYCACHEPREFIX: 9ae.

          Added in version 3.8.

        * ‘-X warn_default_encoding’ issues a *note EncodingWarning:
          1ee5. when the locale-specific default encoding is used for
          opening files.  See also *note PYTHONWARNDEFAULTENCODING: 7c0.

          Added in version 3.10.

        * ‘-X no_debug_ranges’ disables the inclusion of the tables
          mapping extra location information (end line, start column
          offset and end column offset) to every instruction in code
          objects.  This is useful when smaller code objects and pyc
          files are desired as well as suppressing the extra visual
          location indicators when the interpreter displays tracebacks.
          See also *note PYTHONNODEBUGRANGES: 5b9.

          Added in version 3.11.

        * ‘-X frozen_modules’ determines whether or not frozen modules
          are ignored by the import machinery.  A value of ‘on’ means
          they get imported and ‘off’ means they are ignored.  The
          default is ‘on’ if this is an installed Python (the normal
          case).  If it’s under development (running from the source
          tree) then the default is ‘off’.  Note that the
          ‘importlib_bootstrap’ and ‘importlib_bootstrap_external’
          frozen modules are always used, even if this flag is set to
          ‘off’.  See also *note PYTHON_FROZEN_MODULES: 18e.

          Added in version 3.11.

        * ‘-X perf’ enables support for the Linux ‘perf’ profiler.  When
          this option is provided, the ‘perf’ profiler will be able to
          report Python calls.  This option is only available on some
          platforms and will do nothing if is not supported on the
          current system.  The default value is “off”.  See also *note
          PYTHONPERFSUPPORT: 471. and *note Python support for the Linux
          perf profiler: 18f.

          Added in version 3.12.

        * ‘-X perf_jit’ enables support for the Linux ‘perf’ profiler
          with DWARF support.  When this option is provided, the ‘perf’
          profiler will be able to report Python calls using DWARF
          information.  This option is only available on some platforms
          and will do nothing if is not supported on the current system.
          The default value is “off”.  See also *note
          PYTHON_PERF_JIT_SUPPORT: 190. and *note Python support for the
          Linux perf profiler: 18f.

          Added in version 3.13.

        * ‘-X cpu_count=N’ overrides *note os.cpu_count(): 1c5, *note
          os.process_cpu_count(): 1c4, and *note
          multiprocessing.cpu_count(): fa8.  'n' must be greater than or
          equal to 1.  This option may be useful for users who need to
          limit CPU resources of a container system.  See also *note
          PYTHON_CPU_COUNT: 210.  If 'n' is ‘default’, nothing is
          overridden.

          Added in version 3.13.

        * ‘-X presite=PACKAGE.MODULE’ specifies a module that should be
          imported before the *note site: c7. module is executed and
          before the *note __main__: 1. module exists.  Therefore, the
          imported module isn’t ‘__main__’.  This can be used to execute
          code early during Python initialization.  Python needs to be
          *note built in debug mode: 1f9. for this option to exist.  See
          also *note PYTHON_PRESITE: 1ee6.

          Added in version 3.13.

        * ‘-X gil=0,1’ forces the GIL to be disabled or enabled,
          respectively.  Setting to ‘0’ is only available in builds
          configured with *note -disable-gil: 174.  See also *note
          PYTHON_GIL: 175. and *note Free-threaded CPython: 13f.

          Added in version 3.13.

     It also allows passing arbitrary values and retrieving them through
     the *note sys._xoptions: 1ee7. dictionary.

     Added in version 3.2.

     Changed in version 3.9: Removed the ‘-X showalloccount’ option.

     Changed in version 3.10: Removed the ‘-X oldparser’ option.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0488/

   (2) https://peps.python.org/pep-0488/

   (3) https://peps.python.org/pep-0488/

   (4) https://peps.python.org/pep-0488/

   (5) https://peps.python.org/pep-0370/


File: python.info,  Node: Controlling color,  Next: Options you shouldn’t use,  Prev: Miscellaneous options,  Up: Command line

3.1.1.4 Controlling color
.........................

The Python interpreter is configured by default to use colors to
highlight output in certain situations such as when displaying
tracebacks.  This behavior can be controlled by setting different
environment variables.

Setting the environment variable ‘TERM’ to ‘dumb’ will disable color.

If the FORCE_COLOR(1) environment variable is set, then color will be
enabled regardless of the value of TERM. This is useful on CI systems
which aren’t terminals but can still display ANSI escape sequences.

If the NO_COLOR(2) environment variable is set, Python will disable all
color in the output.  This takes precedence over ‘FORCE_COLOR’.

All these environment variables are used also by other tools to control
color output.  To control the color output only in the Python
interpreter, the *note PYTHON_COLORS: 14a. environment variable can be
used.  This variable takes precedence over ‘NO_COLOR’, which in turn
takes precedence over ‘FORCE_COLOR’.

   ---------- Footnotes ----------

   (1) https://force-color.org/

   (2) https://no-color.org/


File: python.info,  Node: Options you shouldn’t use,  Prev: Controlling color,  Up: Command line

3.1.1.5 Options you shouldn’t use
.................................

 -- Option: -J

     Reserved for use by Jython(1).

   ---------- Footnotes ----------

   (1) https://www.jython.org/


File: python.info,  Node: Environment variables,  Prev: Command line,  Up: Command line and environment

3.1.2 Environment variables
---------------------------

These environment variables influence Python’s behavior, they are
processed before the command-line switches other than -E or -I. It is
customary that command-line switches override environmental variables
where there is a conflict.

 -- Environment Variable: PYTHONHOME

     Change the location of the standard Python libraries.  By default,
     the libraries are searched in ‘`prefix'/lib/python`version'’ and
     ‘`exec_prefix'/lib/python`version'’, where ‘`prefix'’ and
     ‘`exec_prefix'’ are installation-dependent directories, both
     defaulting to ‘/usr/local’.

     When *note PYTHONHOME: 3bf. is set to a single directory, its value
     replaces both ‘`prefix'’ and ‘`exec_prefix'’.  To specify different
     values for these, set ‘PYTHONHOME’ to ‘`prefix':`exec_prefix'’.

 -- Environment Variable: PYTHONPATH

     Augment the default search path for module files.  The format is
     the same as the shell’s ‘PATH’: one or more directory pathnames
     separated by *note os.pathsep: 1eec. (e.g.  colons on Unix or
     semicolons on Windows).  Non-existent directories are silently
     ignored.

     In addition to normal directories, individual *note PYTHONPATH:
     1058. entries may refer to zipfiles containing pure Python modules
     (in either source or compiled form).  Extension modules cannot be
     imported from zipfiles.

     The default search path is installation dependent, but generally
     begins with ‘`prefix'/lib/python`version'’ (see *note PYTHONHOME:
     3bf. above).  It is 'always' appended to *note PYTHONPATH: 1058.

     An additional directory will be inserted in the search path in
     front of *note PYTHONPATH: 1058. as described above under *note
     Interface options: 1ed2.  The search path can be manipulated from
     within a Python program as the variable *note sys.path: 3b7.

 -- Environment Variable: PYTHONSAFEPATH

     If this is set to a non-empty string, don’t prepend a potentially
     unsafe path to *note sys.path: 3b7.: see the *note -P: 5a7. option
     for details.

     Added in version 3.11.

 -- Environment Variable: PYTHONPLATLIBDIR

     If this is set to a non-empty string, it overrides the *note
     sys.platlibdir: 942. value.

     Added in version 3.9.

 -- Environment Variable: PYTHONSTARTUP

     If this is the name of a readable file, the Python commands in that
     file are executed before the first prompt is displayed in
     interactive mode.  The file is executed in the same namespace where
     interactive commands are executed so that objects defined or
     imported in it can be used without qualification in the interactive
     session.  You can also change the prompts *note sys.ps1: 1eed. and
     *note sys.ps2: 1eee. and the hook *note sys.__interactivehook__:
     1002. in this file.

     Raises an *note auditing event: 1a15. ‘cpython.run_startup’ with
     the filename as the argument when called on startup.

 -- Environment Variable: PYTHONOPTIMIZE

     If this is set to a non-empty string it is equivalent to specifying
     the *note -O: de3. option.  If set to an integer, it is equivalent
     to specifying ‘-O’ multiple times.

 -- Environment Variable: PYTHONBREAKPOINT

     If this is set, it names a callable using dotted-path notation.
     The module containing the callable will be imported and then the
     callable will be run by the default implementation of *note
     sys.breakpointhook(): af0. which itself is called by built-in *note
     breakpoint(): 234.  If not set, or set to the empty string, it is
     equivalent to the value “pdb.set_trace”.  Setting this to the
     string “0” causes the default implementation of
     ‘sys.breakpointhook()’ to do nothing but return immediately.

     Added in version 3.7.

 -- Environment Variable: PYTHONDEBUG

     If this is set to a non-empty string it is equivalent to specifying
     the *note -d: 1eda. option.  If set to an integer, it is equivalent
     to specifying ‘-d’ multiple times.

     This environment variable requires a *note debug build of Python:
     1f9, otherwise it’s ignored.

 -- Environment Variable: PYTHONINSPECT

     If this is set to a non-empty string it is equivalent to specifying
     the *note -i: 152a. option.

     This variable can also be modified by Python code using *note
     os.environ: 11fe. to force inspect mode on program termination.

     Raises an *note auditing event: 1a15. ‘cpython.run_stdin’ with no
     arguments.

     Changed in version 3.12.5: (also 3.11.10, 3.10.15, 3.9.20, and
     3.8.20) Emits audit events.

     Changed in version 3.13: Uses PyREPL if possible, in which case
     *note PYTHONSTARTUP: 1003. is also executed.  Emits audit events.

 -- Environment Variable: PYTHONUNBUFFERED

     If this is set to a non-empty string it is equivalent to specifying
     the *note -u: 1b36. option.

 -- Environment Variable: PYTHONVERBOSE

     If this is set to a non-empty string it is equivalent to specifying
     the *note -v: 1473. option.  If set to an integer, it is equivalent
     to specifying ‘-v’ multiple times.

 -- Environment Variable: PYTHONCASEOK

     If this is set, Python ignores case in *note import: 5e5.
     statements.  This only works on Windows and macOS.

 -- Environment Variable: PYTHONDONTWRITEBYTECODE

     If this is set to a non-empty string, Python won’t try to write
     ‘.pyc’ files on the import of source modules.  This is equivalent
     to specifying the *note -B: 141b. option.

 -- Environment Variable: PYTHONPYCACHEPREFIX

     If this is set, Python will write ‘.pyc’ files in a mirror
     directory tree at this path, instead of in ‘__pycache__’
     directories within the source tree.  This is equivalent to
     specifying the *note -X: 176. ‘pycache_prefix=PATH’ option.

     Added in version 3.8.

 -- Environment Variable: PYTHONHASHSEED

     If this variable is not set or set to ‘random’, a random value is
     used to seed the hashes of str and bytes objects.

     If *note PYTHONHASHSEED: 10bb. is set to an integer value, it is
     used as a fixed seed for generating the hash() of the types covered
     by the hash randomization.

     Its purpose is to allow repeatable hashing, such as for selftests
     for the interpreter itself, or to allow a cluster of python
     processes to share hash values.

     The integer must be a decimal number in the range [0,4294967295].
     Specifying the value 0 will disable hash randomization.

     Added in version 3.2.3.

 -- Environment Variable: PYTHONINTMAXSTRDIGITS

     If this variable is set to an integer, it is used to configure the
     interpreter’s global *note integer string conversion length
     limitation: 5f8.

     Added in version 3.11.

 -- Environment Variable: PYTHONIOENCODING

     If this is set before running the interpreter, it overrides the
     encoding used for stdin/stdout/stderr, in the syntax
     ‘encodingname:errorhandler’.  Both the ‘encodingname’ and the
     ‘:errorhandler’ parts are optional and have the same meaning as in
     *note str.encode(): 8de.

     For stderr, the ‘:errorhandler’ part is ignored; the handler will
     always be ‘'backslashreplace'’.

     Changed in version 3.4: The ‘encodingname’ part is now optional.

     Changed in version 3.6: On Windows, the encoding specified by this
     variable is ignored for interactive console buffers unless *note
     PYTHONLEGACYWINDOWSSTDIO: c7c. is also specified.  Files and pipes
     redirected through the standard streams are not affected.

 -- Environment Variable: PYTHONNOUSERSITE

     If this is set, Python won’t add the *note user site-packages
     directory: 1edd. to *note sys.path: 3b7.

     See also
     ........

     PEP 370(1) – Per user site-packages directory

 -- Environment Variable: PYTHONUSERBASE

     Defines the *note user base directory: 1366, which is used to
     compute the path of the *note user site-packages directory: 1edd.
     and *note installation paths: 1eef. for ‘python -m pip install
     --user’.

     See also
     ........

     PEP 370(2) – Per user site-packages directory

 -- Environment Variable: PYTHONEXECUTABLE

     If this environment variable is set, ‘sys.argv[0]’ will be set to
     its value instead of the value got through the C runtime.  Only
     works on macOS.

 -- Environment Variable: PYTHONWARNINGS

     This is equivalent to the *note -W: 8d0. option.  If set to a comma
     separated string, it is equivalent to specifying ‘-W’ multiple
     times, with filters later in the list taking precedence over those
     earlier in the list.

     The simplest settings apply a particular action unconditionally to
     all warnings emitted by a process (even those that are otherwise
     ignored by default):

          PYTHONWARNINGS=default  # Warn once per call location
          PYTHONWARNINGS=error    # Convert to exceptions
          PYTHONWARNINGS=always   # Warn every time
          PYTHONWARNINGS=all      # Same as PYTHONWARNINGS=always
          PYTHONWARNINGS=module   # Warn once per calling module
          PYTHONWARNINGS=once     # Warn once per Python process
          PYTHONWARNINGS=ignore   # Never warn

     See *note The Warnings Filter: 8d2. and *note Describing Warning
     Filters: 1ee1. for more details.

 -- Environment Variable: PYTHONFAULTHANDLER

     If this environment variable is set to a non-empty string, *note
     faulthandler.enable(): cc4. is called at startup: install a handler
     for *note SIGSEGV: 10be, *note SIGFPE: 10bf, *note SIGABRT: 10c0,
     *note SIGBUS: 10c1. and *note SIGILL: 10c2. signals to dump the
     Python traceback.  This is equivalent to *note -X: 176.
     ‘faulthandler’ option.

     Added in version 3.3.

 -- Environment Variable: PYTHONTRACEMALLOC

     If this environment variable is set to a non-empty string, start
     tracing Python memory allocations using the *note tracemalloc: ff.
     module.  The value of the variable is the maximum number of frames
     stored in a traceback of a trace.  For example,
     ‘PYTHONTRACEMALLOC=1’ stores only the most recent frame.  See the
     *note tracemalloc.start(): 1ee3. function for more information.
     This is equivalent to setting the *note -X: 176. ‘tracemalloc’
     option.

     Added in version 3.4.

 -- Environment Variable: PYTHONPROFILEIMPORTTIME

     If this environment variable is set to a non-empty string, Python
     will show how long each import takes.  This is equivalent to
     setting the *note -X: 176. ‘importtime’ option.

     Added in version 3.7.

 -- Environment Variable: PYTHONASYNCIODEBUG

     If this environment variable is set to a non-empty string, enable
     the *note debug mode: 1ef2. of the *note asyncio: a. module.

     Added in version 3.4.

 -- Environment Variable: PYTHONMALLOC

     Set the Python memory allocators and/or install debug hooks.

     Set the family of memory allocators used by Python:

        * ‘default’: use the *note default memory allocators: 1ef3.

        * ‘malloc’: use the ‘malloc()’ function of the C library for all
          domains (*note PYMEM_DOMAIN_RAW: 1ef4, *note PYMEM_DOMAIN_MEM:
          c8a, *note PYMEM_DOMAIN_OBJ: c88.).

        * ‘pymalloc’: use the *note pymalloc allocator: d37. for *note
          PYMEM_DOMAIN_MEM: c8a. and *note PYMEM_DOMAIN_OBJ: c88.
          domains and use the ‘malloc()’ function for the *note
          PYMEM_DOMAIN_RAW: 1ef4. domain.

        * ‘mimalloc’: use the *note mimalloc allocator: 1ef5. for *note
          PYMEM_DOMAIN_MEM: c8a. and *note PYMEM_DOMAIN_OBJ: c88.
          domains and use the ‘malloc()’ function for the *note
          PYMEM_DOMAIN_RAW: 1ef4. domain.

     Install *note debug hooks: 1ef6.:

        * ‘debug’: install debug hooks on top of the *note default
          memory allocators: 1ef3.

        * ‘malloc_debug’: same as ‘malloc’ but also install debug hooks.

        * ‘pymalloc_debug’: same as ‘pymalloc’ but also install debug
          hooks.

        * ‘mimalloc_debug’: same as ‘mimalloc’ but also install debug
          hooks.

     Added in version 3.6.

     Changed in version 3.7: Added the ‘"default"’ allocator.

 -- Environment Variable: PYTHONMALLOCSTATS

     If set to a non-empty string, Python will print statistics of the
     *note pymalloc memory allocator: d37. every time a new pymalloc
     object arena is created, and on shutdown.

     This variable is ignored if the *note PYTHONMALLOC: c85.
     environment variable is used to force the ‘malloc()’ allocator of
     the C library, or if Python is configured without ‘pymalloc’
     support.

     Changed in version 3.6: This variable can now also be used on
     Python compiled in release mode.  It now has no effect if set to an
     empty string.

 -- Environment Variable: PYTHONLEGACYWINDOWSFSENCODING

     If set to a non-empty string, the default *note filesystem encoding
     and error handler: 53e. mode will revert to their pre-3.6 values of
     ‘mbcs’ and ‘replace’, respectively.  Otherwise, the new defaults
     ‘utf-8’ and ‘surrogatepass’ are used.

     This may also be enabled at runtime with *note
     sys._enablelegacywindowsfsencoding(): 2ae.

     *note Availability: 1ef7.: Windows.

     Added in version 3.6: See PEP 529(3) for more details.

 -- Environment Variable: PYTHONLEGACYWINDOWSSTDIO

     If set to a non-empty string, does not use the new console reader
     and writer.  This means that Unicode characters will be encoded
     according to the active console code page, rather than using utf-8.

     This variable is ignored if the standard streams are redirected (to
     files or pipes) rather than referring to console buffers.

     *note Availability: 1ef7.: Windows.

     Added in version 3.6.

 -- Environment Variable: PYTHONCOERCECLOCALE

     If set to the value ‘0’, causes the main Python command line
     application to skip coercing the legacy ASCII-based C and POSIX
     locales to a more capable UTF-8 based alternative.

     If this variable is 'not' set (or is set to a value other than
     ‘0’), the ‘LC_ALL’ locale override environment variable is also not
     set, and the current locale reported for the ‘LC_CTYPE’ category is
     either the default ‘C’ locale, or else the explicitly ASCII-based
     ‘POSIX’ locale, then the Python CLI will attempt to configure the
     following locales for the ‘LC_CTYPE’ category in the order listed
     before loading the interpreter runtime:

        * ‘C.UTF-8’

        * ‘C.utf8’

        * ‘UTF-8’

     If setting one of these locale categories succeeds, then the
     ‘LC_CTYPE’ environment variable will also be set accordingly in the
     current process environment before the Python runtime is
     initialized.  This ensures that in addition to being seen by both
     the interpreter itself and other locale-aware components running in
     the same process (such as the GNU ‘readline’ library), the updated
     setting is also seen in subprocesses (regardless of whether or not
     those processes are running a Python interpreter), as well as in
     operations that query the environment rather than the current C
     locale (such as Python’s own *note locale.getdefaultlocale():
     2d9.).

     Configuring one of these locales (either explicitly or via the
     above implicit locale coercion) automatically enables the
     ‘surrogateescape’ *note error handler: 1915. for *note sys.stdin:
     540. and *note sys.stdout: aec. (*note sys.stderr: 943. continues
     to use ‘backslashreplace’ as it does in any other locale).  This
     stream handling behavior can be overridden using *note
     PYTHONIOENCODING: 1045. as usual.

     For debugging purposes, setting ‘PYTHONCOERCECLOCALE=warn’ will
     cause Python to emit warning messages on ‘stderr’ if either the
     locale coercion activates, or else if a locale that 'would' have
     triggered coercion is still active when the Python runtime is
     initialized.

     Also note that even when locale coercion is disabled, or when it
     fails to find a suitable target locale, *note PYTHONUTF8: aee. will
     still activate by default in legacy ASCII-based locales.  Both
     features must be disabled in order to force the interpreter to use
     ‘ASCII’ instead of ‘UTF-8’ for system interfaces.

     *note Availability: 1ef7.: Unix.

     Added in version 3.7: See PEP 538(4) for more details.

 -- Environment Variable: PYTHONDEVMODE

     If this environment variable is set to a non-empty string, enable
     *note Python Development Mode: 1f8, introducing additional runtime
     checks that are too expensive to be enabled by default.  This is
     equivalent to setting the *note -X: 176. ‘dev’ option.

     Added in version 3.7.

 -- Environment Variable: PYTHONUTF8

     If set to ‘1’, enable the *note Python UTF-8 Mode: 659.

     If set to ‘0’, disable the *note Python UTF-8 Mode: 659.

     Setting any other non-empty string causes an error during
     interpreter initialisation.

     Added in version 3.7.

 -- Environment Variable: PYTHONWARNDEFAULTENCODING

     If this environment variable is set to a non-empty string, issue a
     *note EncodingWarning: 1ee5. when the locale-specific default
     encoding is used.

     See *note Opt-in EncodingWarning: 1ef8. for details.

     Added in version 3.10.

 -- Environment Variable: PYTHONNODEBUGRANGES

     If this variable is set, it disables the inclusion of the tables
     mapping extra location information (end line, start column offset
     and end column offset) to every instruction in code objects.  This
     is useful when smaller code objects and pyc files are desired as
     well as suppressing the extra visual location indicators when the
     interpreter displays tracebacks.

     Added in version 3.11.

 -- Environment Variable: PYTHONPERFSUPPORT

     If this variable is set to a nonzero value, it enables support for
     the Linux ‘perf’ profiler so Python calls can be detected by it.

     If set to ‘0’, disable Linux ‘perf’ profiler support.

     See also the *note -X perf: 176. command-line option and *note
     Python support for the Linux perf profiler: 18f.

     Added in version 3.12.

 -- Environment Variable: PYTHON_PERF_JIT_SUPPORT

     If this variable is set to a nonzero value, it enables support for
     the Linux ‘perf’ profiler so Python calls can be detected by it
     using DWARF information.

     If set to ‘0’, disable Linux ‘perf’ profiler support.

     See also the *note -X perf_jit: 176. command-line option and *note
     Python support for the Linux perf profiler: 18f.

     Added in version 3.13.

 -- Environment Variable: PYTHON_CPU_COUNT

     If this variable is set to a positive integer, it overrides the
     return values of *note os.cpu_count(): 1c5. and *note
     os.process_cpu_count(): 1c4.

     See also the *note -X cpu_count: 176. command-line option.

     Added in version 3.13.

 -- Environment Variable: PYTHON_FROZEN_MODULES

     If this variable is set to ‘on’ or ‘off’, it determines whether or
     not frozen modules are ignored by the import machinery.  A value of
     ‘on’ means they get imported and ‘off’ means they are ignored.  The
     default is ‘on’ for non-debug builds (the normal case) and ‘off’
     for debug builds.  Note that the ‘importlib_bootstrap’ and
     ‘importlib_bootstrap_external’ frozen modules are always used, even
     if this flag is set to ‘off’.

     See also the *note -X frozen_modules: 176. command-line option.

     Added in version 3.13.

 -- Environment Variable: PYTHON_COLORS

     If this variable is set to ‘1’, the interpreter will colorize
     various kinds of output.  Setting it to ‘0’ deactivates this
     behavior.  See also *note Controlling color: 16b.

     Added in version 3.13.

 -- Environment Variable: PYTHON_BASIC_REPL

     If this variable is set to any value, the interpreter will not
     attempt to load the Python-based *note REPL: 16a. that requires
     *note curses: 2b. and *note readline: ba, and will instead use the
     traditional parser-based REPL.

     Added in version 3.13.

 -- Environment Variable: PYTHON_HISTORY

     This environment variable can be used to set the location of a
     ‘.python_history’ file (by default, it is ‘.python_history’ in the
     user’s home directory).

     Added in version 3.13.

 -- Environment Variable: PYTHON_GIL

     If this variable is set to ‘1’, the global interpreter lock (GIL)
     will be forced on.  Setting it to ‘0’ forces the GIL off (needs
     Python configured with the *note -disable-gil: 174. build option).

     See also the *note -X gil: 176. command-line option, which takes
     precedence over this variable, and *note Free-threaded CPython:
     13f.

     Added in version 3.13.

 -- Environment Variable: PYTHON_JIT

     On builds where experimental just-in-time compilation is available,
     this variable can force the JIT to be disabled (‘0’) or enabled
     (‘1’) at interpreter startup.

     Added in version 3.13.

* Menu:

* Debug-mode variables::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0370/

   (2) https://peps.python.org/pep-0370/

   (3) https://peps.python.org/pep-0529/

   (4) https://peps.python.org/pep-0538/


File: python.info,  Node: Debug-mode variables,  Up: Environment variables

3.1.2.1 Debug-mode variables
............................

 -- Environment Variable: PYTHONDUMPREFS

     If set, Python will dump objects and reference counts still alive
     after shutting down the interpreter.

     Needs Python configured with the *note -with-trace-refs: 398. build
     option.

 -- Environment Variable: PYTHONDUMPREFSFILE

     If set, Python will dump objects and reference counts still alive
     after shutting down the interpreter into a file under the path
     given as the value to this environment variable.

     Needs Python configured with the *note -with-trace-refs: 398. build
     option.

     Added in version 3.11.

 -- Environment Variable: PYTHON_PRESITE

     If this variable is set to a module, that module will be imported
     early in the interpreter lifecycle, before the *note site: c7.
     module is executed, and before the *note __main__: 1. module is
     created.  Therefore, the imported module is not treated as
     ‘__main__’.

     This can be used to execute code early during Python
     initialization.

     To import a submodule, use ‘package.module’ as the value, like in
     an import statement.

     See also the *note -X presite: 176. command-line option, which
     takes precedence over this variable.

     Needs Python configured with the *note -with-pydebug: 427. build
     option.

     Added in version 3.13.


File: python.info,  Node: Using Python on Unix platforms,  Next: Configure Python,  Prev: Command line and environment,  Up: Python Setup and Usage

3.2 Using Python on Unix platforms
==================================

* Menu:

* Getting and installing the latest version of Python::
* Building Python::
* Python-related paths and files::
* Miscellaneous::
* Custom OpenSSL::


File: python.info,  Node: Getting and installing the latest version of Python,  Next: Building Python,  Up: Using Python on Unix platforms

3.2.1 Getting and installing the latest version of Python
---------------------------------------------------------

* Menu:

* On Linux::
* On FreeBSD and OpenBSD::


File: python.info,  Node: On Linux,  Next: On FreeBSD and OpenBSD,  Up: Getting and installing the latest version of Python

3.2.1.1 On Linux
................

Python comes preinstalled on most Linux distributions, and is available
as a package on all others.  However there are certain features you
might want to use that are not available on your distro’s package.  You
can compile the latest version of Python from source.

In the event that the latest version of Python doesn’t come preinstalled
and isn’t in the repositories as well, you can make packages for your
own distro.  Have a look at the following links:

See also
........

‘https://www.debian.org/doc/manuals/maint-guide/first.en.html’

     for Debian users

‘https://en.opensuse.org/Portal:Packaging’

     for OpenSuse users

‘https://docs.fedoraproject.org/en-US/package-maintainers/Packaging_Tutorial_GNU_Hello/’

     for Fedora users

‘https://slackbook.org/html/package-management-making-packages.html’

     for Slackware users

* Menu:

* Installing IDLE::


File: python.info,  Node: Installing IDLE,  Up: On Linux

3.2.1.2 Installing IDLE
.......................

In some cases, IDLE might not be included in your Python installation.

   * For Debian and Ubuntu users:

          sudo apt update
          sudo apt install idle

   * For Fedora, RHEL, and CentOS users:

          sudo dnf install python3-idle

   * For SUSE and OpenSUSE users:

          sudo zypper install python3-idle

   * For Alpine Linux users:

          sudo apk add python3-idle


File: python.info,  Node: On FreeBSD and OpenBSD,  Prev: On Linux,  Up: Getting and installing the latest version of Python

3.2.1.3 On FreeBSD and OpenBSD
..............................

   * FreeBSD users, to add the package use:

          pkg install python3

   * OpenBSD users, to add the package use:

          pkg_add -r python

          pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/<insert your architecture here>/python-<version>.tgz

     For example i386 users get the 2.5.1 version of Python using:

          pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/4.2/packages/i386/python-2.5.1p2.tgz


File: python.info,  Node: Building Python,  Next: Python-related paths and files,  Prev: Getting and installing the latest version of Python,  Up: Using Python on Unix platforms

3.2.2 Building Python
---------------------

If you want to compile CPython yourself, first thing you should do is
get the source(1).  You can download either the latest release’s source
or just grab a fresh clone(2).  (If you want to contribute patches, you
will need a clone.)

The build process consists of the usual commands:

     ./configure
     make
     make install

*note Configuration options: 1f04. and caveats for specific Unix
platforms are extensively documented in the README.rst(3) file in the
root of the Python source tree.

     Warning: ‘make install’ can overwrite or masquerade the ‘python3’
     binary.  ‘make altinstall’ is therefore recommended instead of
     ‘make install’ since it only installs
     ‘`exec_prefix'/bin/python`version'’.

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/source/

   (2) https://devguide.python.org/setup/#get-the-source-code

   (3) https://github.com/python/cpython/tree/3.13/README.rst


File: python.info,  Node: Python-related paths and files,  Next: Miscellaneous,  Prev: Building Python,  Up: Using Python on Unix platforms

3.2.3 Python-related paths and files
------------------------------------

These are subject to difference depending on local installation
conventions; *note prefix: 1f06. and *note exec_prefix: 1f07. are
installation-dependent and should be interpreted as for GNU software;
they may be the same.

For example, on most Linux systems, the default for both is ‘/usr’.

File/directory                                      Meaning
                                                    
---------------------------------------------------------------------------------------------------
                                                    
‘`exec_prefix'/bin/python3’                         Recommended location of the interpreter.
                                                    
                                                    
‘`prefix'/lib/python`version'’,                     Recommended locations of the directories
‘`exec_prefix'/lib/python`version'’                 containing the standard modules.
                                                    
                                                    
‘`prefix'/include/python`version'’,                 Recommended locations of the directories
‘`exec_prefix'/include/python`version'’             containing the include files needed for
                                                    developing Python extensions and embedding
                                                    the interpreter.
                                                    


File: python.info,  Node: Miscellaneous,  Next: Custom OpenSSL,  Prev: Python-related paths and files,  Up: Using Python on Unix platforms

3.2.4 Miscellaneous
-------------------

To easily use Python scripts on Unix, you need to make them executable,
e.g.  with

     $ chmod +x script

and put an appropriate Shebang line at the top of the script.  A good
choice is usually

     #!/usr/bin/env python3

which searches for the Python interpreter in the whole ‘PATH’.  However,
some Unices may not have the ‘env’ command, so you may need to hardcode
‘/usr/bin/python3’ as the interpreter path.

To use shell commands in your Python scripts, look at the *note
subprocess: d6. module.


File: python.info,  Node: Custom OpenSSL,  Prev: Miscellaneous,  Up: Using Python on Unix platforms

3.2.5 Custom OpenSSL
--------------------

  1. To use your vendor’s OpenSSL configuration and system trust store,
     locate the directory with ‘openssl.cnf’ file or symlink in ‘/etc’.
     On most distribution the file is either in ‘/etc/ssl’ or
     ‘/etc/pki/tls’.  The directory should also contain a ‘cert.pem’
     file and/or a ‘certs’ directory.

          $ find /etc/ -name openssl.cnf -printf "%h\n"
          /etc/ssl

  2. Download, build, and install OpenSSL. Make sure you use
     ‘install_sw’ and not ‘install’.  The ‘install_sw’ target does not
     override ‘openssl.cnf’.

          $ curl -O https://www.openssl.org/source/openssl-VERSION.tar.gz
          $ tar xzf openssl-VERSION
          $ pushd openssl-VERSION
          $ ./config \
              --prefix=/usr/local/custom-openssl \
              --libdir=lib \
              --openssldir=/etc/ssl
          $ make -j1 depend
          $ make -j8
          $ make install_sw
          $ popd

  3. Build Python with custom OpenSSL (see the configure
     ‘--with-openssl’ and ‘--with-openssl-rpath’ options)

          $ pushd python-3.x.x
          $ ./configure -C \
              --with-openssl=/usr/local/custom-openssl \
              --with-openssl-rpath=auto \
              --prefix=/usr/local/python-3.x.x
          $ make -j8
          $ make altinstall

     Note: Patch releases of OpenSSL have a backwards compatible ABI.
     You don’t need to recompile Python to update OpenSSL. It’s
     sufficient to replace the custom OpenSSL installation with a newer
     version.


File: python.info,  Node: Configure Python,  Next: Using Python on Windows,  Prev: Using Python on Unix platforms,  Up: Python Setup and Usage

3.3 Configure Python
====================

* Menu:

* Build Requirements::
* Generated files::
* Configure Options::
* Python Build System::
* Compiler and linker flags::


File: python.info,  Node: Build Requirements,  Next: Generated files,  Up: Configure Python

3.3.1 Build Requirements
------------------------

Features and minimum versions required to build CPython:

   * A C11(1) compiler.  Optional C11 features(2) are not required.

   * On Windows, Microsoft Visual Studio 2017 or later is required.

   * Support for IEEE 754(3) floating-point numbers and floating-point
     Not-a-Number (NaN)(4).

   * Support for threads.

   * OpenSSL 1.1.1 is the minimum version and OpenSSL 3.0.18 is the
     recommended minimum version for the *note ssl: d0. and *note
     hashlib: 68. extension modules.

   * SQLite 3.15.2 for the *note sqlite3: cf. extension module.

   * Tcl/Tk 8.5.12 for the *note tkinter: f0. module.

   * libmpdec(5) 2.5.0 for the *note decimal: 36. module.

   * Autoconf 2.71 and aclocal 1.16.5 are required to regenerate the
     ‘configure’ script.

Changed in version 3.1: Tcl/Tk version 8.3.1 is now required.

Changed in version 3.5: On Windows, Visual Studio 2015 or later is now
required.  Tcl/Tk version 8.4 is now required.

Changed in version 3.6: Selected C99 features are now required, like
‘<stdint.h>’ and ‘static inline’ functions.

Changed in version 3.7: Thread support and OpenSSL 1.0.2 are now
required.

Changed in version 3.10: OpenSSL 1.1.1 is now required.  Require SQLite
3.7.15.

Changed in version 3.11: C11 compiler, IEEE 754 and NaN support are now
required.  On Windows, Visual Studio 2017 or later is required.  Tcl/Tk
version 8.5.12 is now required for the *note tkinter: f0. module.

Changed in version 3.13: Autoconf 2.71, aclocal 1.16.5 and SQLite 3.15.2
are now required.

See also PEP 7(6) “Style Guide for C Code” and PEP 11(7) “CPython
platform support”.

   ---------- Footnotes ----------

   (1) https://en.cppreference.com/w/c/11

   (2) 
https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features

   (3) https://en.wikipedia.org/wiki/IEEE_754

   (4) https://en.wikipedia.org/wiki/NaN#Floating_point

   (5) https://www.bytereef.org/mpdecimal/doc/libmpdec/

   (6) https://peps.python.org/pep-0007/

   (7) https://peps.python.org/pep-0011/


File: python.info,  Node: Generated files,  Next: Configure Options,  Prev: Build Requirements,  Up: Configure Python

3.3.2 Generated files
---------------------

To reduce build dependencies, Python source code contains multiple
generated files.  Commands to regenerate all generated files:

     make regen-all
     make regen-stdlib-module-names
     make regen-limited-abi
     make regen-configure

The ‘Makefile.pre.in’ file documents generated files, their inputs, and
tools used to regenerate them.  Search for ‘regen-*’ make targets.

* Menu:

* configure script::


File: python.info,  Node: configure script,  Up: Generated files

3.3.2.1 configure script
........................

The ‘make regen-configure’ command regenerates the ‘aclocal.m4’ file and
the ‘configure’ script using the ‘Tools/build/regen-configure.sh’ shell
script which uses an Ubuntu container to get the same tools versions and
have a reproducible output.

The container is optional, the following command can be run locally:

     autoreconf -ivf -Werror

The generated files can change depending on the exact
‘autoconf-archive’, ‘aclocal’ and ‘pkg-config’ versions.


File: python.info,  Node: Configure Options,  Next: Python Build System,  Prev: Generated files,  Up: Configure Python

3.3.3 Configure Options
-----------------------

List all ‘configure’ script options using:

     ./configure --help

See also the ‘Misc/SpecialBuilds.txt’ in the Python source distribution.

* Menu:

* General Options::
* C compiler options::
* Linker options::
* Options for third-party dependencies::
* WebAssembly Options::
* Install Options::
* Performance options::
* Python Debug Build::
* Debug options::
* Linker options: Linker options<2>.
* Libraries options::
* Security Options::
* macOS Options::
* iOS Options::
* Cross Compiling Options::


File: python.info,  Node: General Options,  Next: C compiler options,  Up: Configure Options

3.3.3.1 General Options
.......................

 -- Option: --enable-loadable-sqlite-extensions

     Support loadable extensions in the ‘_sqlite’ extension module
     (default is no) of the *note sqlite3: cf. module.

     See the *note sqlite3.Connection.enable_load_extension(): 844.
     method of the *note sqlite3: cf. module.

     Added in version 3.6.

 -- Option: --disable-ipv6

     Disable IPv6 support (enabled by default if supported), see the
     *note socket: cc. module.

 -- Option: --enable-big-digits=[15|30]

     Define the size in bits of Python *note int: 257. digits: 15 or 30
     bits.

     By default, the digit size is 30.

     Define the ‘PYLONG_BITS_IN_DIGIT’ to ‘15’ or ‘30’.

     See *note sys.int_info.bits_per_digit: 12da.

 -- Option: --with-suffix=SUFFIX

     Set the Python executable suffix to 'SUFFIX'.

     The default suffix is ‘.exe’ on Windows and macOS (‘python.exe’
     executable), ‘.js’ on Emscripten node, ‘.html’ on Emscripten
     browser, ‘.wasm’ on WASI, and an empty string on other platforms
     (‘python’ executable).

     Changed in version 3.11: The default suffix on WASM platform is one
     of ‘.js’, ‘.html’ or ‘.wasm’.

 -- Option: --with-tzpath=<list of absolute paths separated by pathsep>

     Select the default time zone search path for *note zoneinfo.TZPATH:
     1f17.  See the *note Compile-time configuration: 1f18. of the *note
     zoneinfo: 134. module.

     Default:
     ‘/usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo’.

     See *note os.pathsep: 1eec. path separator.

     Added in version 3.9.

 -- Option: --without-decimal-contextvar

     Build the ‘_decimal’ extension module using a thread-local context
     rather than a coroutine-local context (default), see the *note
     decimal: 36. module.

     See *note decimal.HAVE_CONTEXTVAR: 1f1a. and the *note contextvars:
     24. module.

     Added in version 3.9.

 -- Option: --with-dbmliborder=<list of backend names>

     Override order to check db backends for the *note dbm: 31. module

     A valid value is a colon (‘:’) separated string with the backend
     names:

        * ‘ndbm’;

        * ‘gdbm’;

        * ‘bdb’.

 -- Option: --without-c-locale-coercion

     Disable C locale coercion to a UTF-8 based locale (enabled by
     default).

     Don’t define the ‘PY_COERCE_C_LOCALE’ macro.

     See *note PYTHONCOERCECLOCALE: aeb. and the PEP 538(1).

 -- Option: --without-freelists

     Disable all freelists except the empty tuple singleton.

     Added in version 3.11.

 -- Option: --with-platlibdir=DIRNAME

     Python library directory name (default is ‘lib’).

     Fedora and SuSE use ‘lib64’ on 64-bit platforms.

     See *note sys.platlibdir: 942.

     Added in version 3.9.

 -- Option: --with-wheel-pkg-dir=PATH

     Directory of wheel packages used by the *note ensurepip: 55. module
     (none by default).

     Some Linux distribution packaging policies recommend against
     bundling dependencies.  For example, Fedora installs wheel packages
     in the ‘/usr/share/python-wheels/’ directory and don’t install the
     ‘ensurepip._bundled’ package.

     Added in version 3.10.

 -- Option: --with-pkg-config=[check|yes|no]

     Whether configure should use ‘pkg-config’ to detect build
     dependencies.

        * ‘check’ (default): ‘pkg-config’ is optional

        * ‘yes’: ‘pkg-config’ is mandatory

        * ‘no’: configure does not use ‘pkg-config’ even when present

     Added in version 3.11.

 -- Option: --enable-pystats

     Turn on internal Python performance statistics gathering.

     By default, statistics gathering is off.  Use ‘python3 -X pystats’
     command or set ‘PYTHONSTATS=1’ environment variable to turn on
     statistics gathering at Python startup.

     At Python exit, dump statistics if statistics gathering was on and
     not cleared.

     Effects:

        * Add *note -X pystats: 176. command line option.

        * Add ‘PYTHONSTATS’ environment variable.

        * Define the ‘Py_STATS’ macro.

        * Add functions to the *note sys: d9. module:

             * ‘sys._stats_on()’: Turns on statistics gathering.

             * ‘sys._stats_off()’: Turns off statistics gathering.

             * ‘sys._stats_clear()’: Clears the statistics.

             * ‘sys._stats_dump()’: Dump statistics to file, and clears
               the statistics.

     The statistics will be dumped to a arbitrary (probably unique) file
     in ‘/tmp/py_stats/’ (Unix) or ‘C:\temp\py_stats\’ (Windows).  If
     that directory does not exist, results will be printed on stderr.

     Use ‘Tools/scripts/summarize_stats.py’ to read the stats.

     Statistics:

        * Opcode:

             * Specialization: success, failure, hit, deferred, miss,
               deopt, failures;

             * Execution count;

             * Pair count.

        * Call:

             * Inlined Python calls;

             * PyEval calls;

             * Frames pushed;

             * Frame object created;

             * Eval calls: vector, generator, legacy, function
               VECTORCALL, build class, slot, function “ex”, API,
               method.

        * Object:

             * incref and decref;

             * interpreter incref and decref;

             * allocations: all, 512 bytes, 4 kiB, big;

             * free;

             * to/from free lists;

             * dictionary materialized/dematerialized;

             * type cache;

             * optimization attempts;

             * optimization traces created/executed;

             * uops executed.

        * Garbage collector:

             * Garbage collections;

             * Objects visited;

             * Objects collected.

     Added in version 3.11.

 -- Option: --disable-gil

     Enables 'experimental' support for running Python without the *note
     global interpreter lock: 148. (GIL): free threading build.

     Defines the ‘Py_GIL_DISABLED’ macro and adds ‘"t"’ to *note
     sys.abiflags: a72.

     See *note Free-threaded CPython: 13f. for more detail.

     Added in version 3.13.

 -- Option: --enable-experimental-jit=[no|yes|yes-off|interpreter]

     Indicate how to integrate the *note JIT compiler: 140.

        * ‘no’ - build the interpreter without the JIT.

        * ‘yes’ - build the interpreter with the JIT.

        * ‘yes-off’ - build the interpreter with the JIT but disable it
          by default.

        * ‘interpreter’ - build the interpreter without the JIT, but
          with the tier 2 enabled interpreter.

     By convention, ‘--enable-experimental-jit’ is a shorthand for
     ‘--enable-experimental-jit=yes’.

          Note: When building CPython with JIT enabled, ensure that your
          system has Python 3.11 or later installed.

     Added in version 3.13.

 -- Option: PKG_CONFIG

     Path to ‘pkg-config’ utility.

 -- Option: PKG_CONFIG_LIBDIR

 -- Option: PKG_CONFIG_PATH

     ‘pkg-config’ options.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0538/


File: python.info,  Node: C compiler options,  Next: Linker options,  Prev: General Options,  Up: Configure Options

3.3.3.2 C compiler options
..........................

 -- Option: CC

     C compiler command.

 -- Option: CFLAGS

     C compiler flags.

 -- Option: CPP

     C preprocessor command.

 -- Option: CPPFLAGS

     C preprocessor flags, e.g.  ‘-IINCLUDE_DIR’.


File: python.info,  Node: Linker options,  Next: Options for third-party dependencies,  Prev: C compiler options,  Up: Configure Options

3.3.3.3 Linker options
......................

 -- Option: LDFLAGS

     Linker flags, e.g.  ‘-LLIBRARY_DIRECTORY’.

 -- Option: LIBS

     Libraries to pass to the linker, e.g.  ‘-lLIBRARY’.

 -- Option: MACHDEP

     Name for machine-dependent library files.


File: python.info,  Node: Options for third-party dependencies,  Next: WebAssembly Options,  Prev: Linker options,  Up: Configure Options

3.3.3.4 Options for third-party dependencies
............................................

Added in version 3.11.

 -- Option: BZIP2_CFLAGS

 -- Option: BZIP2_LIBS

     C compiler and linker flags to link Python to ‘libbz2’, used by
     *note bz2: 13. module, overriding ‘pkg-config’.

 -- Option: CURSES_CFLAGS

 -- Option: CURSES_LIBS

     C compiler and linker flags for ‘libncurses’ or ‘libncursesw’, used
     by *note curses: 2b. module, overriding ‘pkg-config’.

 -- Option: GDBM_CFLAGS

 -- Option: GDBM_LIBS

     C compiler and linker flags for ‘gdbm’.

 -- Option: LIBB2_CFLAGS

 -- Option: LIBB2_LIBS

     C compiler and linker flags for ‘libb2’ (*note BLAKE2: 1f36.), used
     by *note hashlib: 68. module, overriding ‘pkg-config’.

 -- Option: LIBEDIT_CFLAGS

 -- Option: LIBEDIT_LIBS

     C compiler and linker flags for ‘libedit’, used by *note readline:
     ba. module, overriding ‘pkg-config’.

 -- Option: LIBFFI_CFLAGS

 -- Option: LIBFFI_LIBS

     C compiler and linker flags for ‘libffi’, used by *note ctypes: 2a.
     module, overriding ‘pkg-config’.

 -- Option: LIBMPDEC_CFLAGS

 -- Option: LIBMPDEC_LIBS

     C compiler and linker flags for ‘libmpdec’, used by *note decimal:
     36. module, overriding ‘pkg-config’.

          Note: These environment variables have no effect unless *note
          -with-system-libmpdec: 415. is specified.

 -- Option: LIBLZMA_CFLAGS

 -- Option: LIBLZMA_LIBS

     C compiler and linker flags for ‘liblzma’, used by *note lzma: 8a.
     module, overriding ‘pkg-config’.

 -- Option: LIBREADLINE_CFLAGS

 -- Option: LIBREADLINE_LIBS

     C compiler and linker flags for ‘libreadline’, used by *note
     readline: ba. module, overriding ‘pkg-config’.

 -- Option: LIBSQLITE3_CFLAGS

 -- Option: LIBSQLITE3_LIBS

     C compiler and linker flags for ‘libsqlite3’, used by *note
     sqlite3: cf. module, overriding ‘pkg-config’.

 -- Option: LIBUUID_CFLAGS

 -- Option: LIBUUID_LIBS

     C compiler and linker flags for ‘libuuid’, used by *note uuid: 110.
     module, overriding ‘pkg-config’.

 -- Option: PANEL_CFLAGS

 -- Option: PANEL_LIBS

     C compiler and linker flags for PANEL, overriding ‘pkg-config’.

     C compiler and linker flags for ‘libpanel’ or ‘libpanelw’, used by
     *note curses.panel: 2d. module, overriding ‘pkg-config’.

 -- Option: TCLTK_CFLAGS

 -- Option: TCLTK_LIBS

     C compiler and linker flags for TCLTK, overriding ‘pkg-config’.

 -- Option: ZLIB_CFLAGS

 -- Option: ZLIB_LIBS

     C compiler and linker flags for ‘libzlib’, used by *note gzip: 67.
     module, overriding ‘pkg-config’.


File: python.info,  Node: WebAssembly Options,  Next: Install Options,  Prev: Options for third-party dependencies,  Up: Configure Options

3.3.3.5 WebAssembly Options
...........................

 -- Option: --with-emscripten-target=[browser|node]

     Set build flavor for ‘wasm32-emscripten’.

        * ‘browser’ (default): preload minimal stdlib, default MEMFS.

        * ‘node’: NODERAWFS and pthread support.

     Added in version 3.11.

 -- Option: --enable-wasm-dynamic-linking

     Turn on dynamic linking support for WASM.

     Dynamic linking enables ‘dlopen’.  File size of the executable
     increases due to limited dead code elimination and additional
     features.

     Added in version 3.11.

 -- Option: --enable-wasm-pthreads

     Turn on pthreads support for WASM.

     Added in version 3.11.


File: python.info,  Node: Install Options,  Next: Performance options,  Prev: WebAssembly Options,  Up: Configure Options

3.3.3.6 Install Options
.......................

 -- Option: --prefix=PREFIX

     Install architecture-independent files in PREFIX. On Unix, it
     defaults to ‘/usr/local’.

     This value can be retrieved at runtime using *note sys.prefix: 3b9.

     As an example, one can use ‘--prefix="$HOME/.local/"’ to install a
     Python in its home directory.

 -- Option: --exec-prefix=EPREFIX

     Install architecture-dependent files in EPREFIX, defaults to *note
     -prefix: 1f06.

     This value can be retrieved at runtime using *note sys.exec_prefix:
     3b5.

 -- Option: --disable-test-modules

     Don’t build nor install test modules, like the *note test: e2.
     package or the ‘_testcapi’ extension module (built and installed by
     default).

     Added in version 3.10.

 -- Option: --with-ensurepip=[upgrade|install|no]

     Select the *note ensurepip: 55. command run on Python installation:

        * ‘upgrade’ (default): run ‘python -m ensurepip --altinstall
          --upgrade’ command.

        * ‘install’: run ‘python -m ensurepip --altinstall’ command;

        * ‘no’: don’t run ensurepip;

     Added in version 3.6.


File: python.info,  Node: Performance options,  Next: Python Debug Build,  Prev: Install Options,  Up: Configure Options

3.3.3.7 Performance options
...........................

Configuring Python using ‘--enable-optimizations --with-lto’ (PGO + LTO)
is recommended for best performance.  The experimental ‘--enable-bolt’
flag can also be used to improve performance.

 -- Option: --enable-optimizations

     Enable Profile Guided Optimization (PGO) using *note PROFILE_TASK:
     181d. (disabled by default).

     The C compiler Clang requires ‘llvm-profdata’ program for PGO. On
     macOS, GCC also requires it: GCC is just an alias to Clang on
     macOS.

     Disable also semantic interposition in libpython if
     ‘--enable-shared’ and GCC is used: add
     ‘-fno-semantic-interposition’ to the compiler and linker flags.

          Note: During the build, you may encounter compiler warnings
          about profile data not being available for some source files.
          These warnings are harmless, as only a subset of the code is
          exercised during profile data acquisition.  To disable these
          warnings on Clang, manually suppress them by adding
          ‘-Wno-profile-instr-unprofiled’ to *note CFLAGS: 1506.

     Added in version 3.6.

     Changed in version 3.10: Use ‘-fno-semantic-interposition’ on GCC.

 -- Environment Variable: PROFILE_TASK

     Environment variable used in the Makefile: Python command line
     arguments for the PGO generation task.

     Default: ‘-m test --pgo --timeout=$(TESTTIMEOUT)’.

     Added in version 3.8.

     Changed in version 3.13: Task failure is no longer ignored
     silently.

 -- Option: --with-lto=[full|thin|no|yes]

     Enable Link Time Optimization (LTO) in any build (disabled by
     default).

     The C compiler Clang requires ‘llvm-ar’ for LTO (‘ar’ on macOS), as
     well as an LTO-aware linker (‘ld.gold’ or ‘lld’).

     Added in version 3.6.

     Added in version 3.11: To use ThinLTO feature, use
     ‘--with-lto=thin’ on Clang.

     Changed in version 3.12: Use ThinLTO as the default optimization
     policy on Clang if the compiler accepts the flag.

 -- Option: --enable-bolt

     Enable usage of the BOLT post-link binary optimizer(1) (disabled by
     default).

     BOLT is part of the LLVM project but is not always included in
     their binary distributions.  This flag requires that ‘llvm-bolt’
     and ‘merge-fdata’ are available.

     BOLT is still a fairly new project so this flag should be
     considered experimental for now.  Because this tool operates on
     machine code its success is dependent on a combination of the build
     environment + the other optimization configure args + the CPU
     architecture, and not all combinations are supported.  BOLT
     versions before LLVM 16 are known to crash BOLT under some
     scenarios.  Use of LLVM 16 or newer for BOLT optimization is
     strongly encouraged.

     The ‘BOLT_INSTRUMENT_FLAGS’ and ‘BOLT_APPLY_FLAGS’ ‘configure’
     variables can be defined to override the default set of arguments
     for ‘llvm-bolt’ to instrument and apply BOLT data to binaries,
     respectively.

     Added in version 3.12.

 -- Option: BOLT_APPLY_FLAGS

     Arguments to ‘llvm-bolt’ when creating a BOLT optimized binary(2).

     Added in version 3.12.

 -- Option: BOLT_INSTRUMENT_FLAGS

     Arguments to ‘llvm-bolt’ when instrumenting binaries.

     Added in version 3.12.

 -- Option: --with-computed-gotos

     Enable computed gotos in evaluation loop (enabled by default on
     supported compilers).

 -- Option: --without-mimalloc

     Disable the fast *note mimalloc: 1ef5. allocator (enabled by
     default).

     See also *note PYTHONMALLOC: c85. environment variable.

 -- Option: --without-pymalloc

     Disable the specialized Python memory allocator *note pymalloc:
     d37. (enabled by default).

     See also *note PYTHONMALLOC: c85. environment variable.

 -- Option: --without-doc-strings

     Disable static documentation strings to reduce the memory footprint
     (enabled by default).  Documentation strings defined in Python are
     not affected.

     Don’t define the ‘WITH_DOC_STRINGS’ macro.

     See the ‘PyDoc_STRVAR()’ macro.

 -- Option: --enable-profiling

     Enable C-level code profiling with ‘gprof’ (disabled by default).

 -- Option: --with-strict-overflow

     Add ‘-fstrict-overflow’ to the C compiler flags (by default we add
     ‘-fno-strict-overflow’ instead).

   ---------- Footnotes ----------

   (1) https://github.com/llvm/llvm-project/tree/main/bolt

   (2) https://github.com/facebookarchive/BOLT


File: python.info,  Node: Python Debug Build,  Next: Debug options,  Prev: Performance options,  Up: Configure Options

3.3.3.8 Python Debug Build
..........................

A debug build is Python built with the *note -with-pydebug: 427.
configure option.

Effects of a debug build:

   * Display all warnings by default: the list of default warning
     filters is empty in the *note warnings: 112. module.

   * Add ‘d’ to *note sys.abiflags: a72.

   * Add ‘sys.gettotalrefcount()’ function.

   * Add *note -X showrefcount: 176. command line option.

   * Add *note -d: 1eda. command line option and *note PYTHONDEBUG:
     1edb. environment variable to debug the parser.

   * Add support for the ‘__lltrace__’ variable: enable low-level
     tracing in the bytecode evaluation loop if the variable is defined.

   * Install *note debug hooks on memory allocators: 1ef3. to detect
     buffer overflow and other memory errors.

   * Define ‘Py_DEBUG’ and ‘Py_REF_DEBUG’ macros.

   * Add runtime checks: code surrounded by ‘#ifdef Py_DEBUG’ and
     ‘#endif’.  Enable ‘assert(...)’ and ‘_PyObject_ASSERT(...)’
     assertions: don’t set the ‘NDEBUG’ macro (see also the *note
     -with-assertions: 38f. configure option).  Main runtime checks:

        * Add sanity checks on the function arguments.

        * Unicode and int objects are created with their memory filled
          with a pattern to detect usage of uninitialized objects.

        * Ensure that functions which can clear or replace the current
          exception are not called with an exception raised.

        * Check that deallocator functions don’t change the current
          exception.

        * The garbage collector (*note gc.collect(): a47. function) runs
          some basic checks on objects consistency.

        * The ‘Py_SAFE_DOWNCAST()’ macro checks for integer underflow
          and overflow when downcasting from wide types to narrow types.

See also the *note Python Development Mode: 1f8. and the *note
-with-trace-refs: 398. configure option.

Changed in version 3.8: Release builds are now ABI compatible with debug
builds: defining the ‘Py_DEBUG’ macro no longer implies the
‘Py_TRACE_REFS’ macro (see the *note -with-trace-refs: 398. option).
However, debug builds still expose more symbols than release builds and
code built against a debug build is not necessarily compatible with a
release build.


File: python.info,  Node: Debug options,  Next: Linker options<2>,  Prev: Python Debug Build,  Up: Configure Options

3.3.3.9 Debug options
.....................

 -- Option: --with-pydebug

     *note Build Python in debug mode: 1f9.: define the ‘Py_DEBUG’ macro
     (disabled by default).

 -- Option: --with-trace-refs

     Enable tracing references for debugging purpose (disabled by
     default).

     Effects:

        * Define the ‘Py_TRACE_REFS’ macro.

        * Add *note sys.getobjects(): 42a. function.

        * Add *note PYTHONDUMPREFS: 9b1. environment variable.

     The *note PYTHONDUMPREFS: 9b1. environment variable can be used to
     dump objects and reference counts still alive at Python exit.

     *note Statically allocated objects: 782. are not traced.

     Added in version 3.8.

     Changed in version 3.13: This build is now ABI compatible with
     release build and *note debug build: 1f9.

 -- Option: --with-assertions

     Build with C assertions enabled (default is no): ‘assert(...);’ and
     ‘_PyObject_ASSERT(...);’.

     If set, the ‘NDEBUG’ macro is not defined in the *note OPT: 1f5a.
     compiler variable.

     See also the *note -with-pydebug: 427. option (*note debug build:
     1f9.) which also enables assertions.

     Added in version 3.6.

 -- Option: --with-valgrind

     Enable Valgrind support (default is no).

 -- Option: --with-dtrace

     Enable DTrace support (default is no).

     See *note Instrumenting CPython with DTrace and SystemTap: c8d.

     Added in version 3.6.

 -- Option: --with-address-sanitizer

     Enable AddressSanitizer memory error detector, ‘asan’ (default is
     no).  To improve ASan detection capabilities you may also want to
     combine this with *note -without-pymalloc: 1f55. to disable the
     specialized small-object allocator whose allocations are not
     tracked by ASan.

     Added in version 3.6.

 -- Option: --with-memory-sanitizer

     Enable MemorySanitizer allocation error detector, ‘msan’ (default
     is no).

     Added in version 3.6.

 -- Option: --with-undefined-behavior-sanitizer

     Enable UndefinedBehaviorSanitizer undefined behaviour detector,
     ‘ubsan’ (default is no).

     Added in version 3.6.

 -- Option: --with-thread-sanitizer

     Enable ThreadSanitizer data race detector, ‘tsan’ (default is no).

     Added in version 3.13.


File: python.info,  Node: Linker options<2>,  Next: Libraries options,  Prev: Debug options,  Up: Configure Options

3.3.3.10 Linker options
.......................

 -- Option: --enable-shared

     Enable building a shared Python library: ‘libpython’ (default is
     no).

 -- Option: --without-static-libpython

     Do not build ‘libpythonMAJOR.MINOR.a’ and do not install ‘python.o’
     (built and enabled by default).

     Added in version 3.10.


File: python.info,  Node: Libraries options,  Next: Security Options,  Prev: Linker options<2>,  Up: Configure Options

3.3.3.11 Libraries options
..........................

 -- Option: --with-libs='lib1 ...'

     Link against additional libraries (default is no).

 -- Option: --with-system-expat

     Build the ‘pyexpat’ module using an installed ‘expat’ library
     (default is no).

 -- Option: --with-system-libmpdec

     Build the ‘_decimal’ extension module using an installed
     ‘mpdecimal’ library, see the *note decimal: 36. module (default is
     yes).

     Added in version 3.3.

     Changed in version 3.13: Default to using the installed ‘mpdecimal’
     library.

     Deprecated since version 3.13, will be removed in version 3.16: A
     copy of the ‘mpdecimal’ library sources will no longer be
     distributed with Python 3.16.

     See also
     ........

     *note LIBMPDEC_CFLAGS: 1f3b. and *note LIBMPDEC_LIBS: 1f3c.

 -- Option: --with-readline=readline|editline

     Designate a backend library for the *note readline: ba. module.

        * readline: Use readline as the backend.

        * editline: Use editline as the backend.

     Added in version 3.10.

 -- Option: --without-readline

     Don’t build the *note readline: ba. module (built by default).

     Don’t define the ‘HAVE_LIBREADLINE’ macro.

     Added in version 3.10.

 -- Option: --with-libm=STRING

     Override ‘libm’ math library to 'STRING' (default is
     system-dependent).

 -- Option: --with-libc=STRING

     Override ‘libc’ C library to 'STRING' (default is
     system-dependent).

 -- Option: --with-openssl=DIR

     Root of the OpenSSL directory.

     Added in version 3.7.

 -- Option: --with-openssl-rpath=[no|auto|DIR]

     Set runtime library directory (rpath) for OpenSSL libraries:

        * ‘no’ (default): don’t set rpath;

        * ‘auto’: auto-detect rpath from *note -with-openssl: 1f68. and
          ‘pkg-config’;

        * 'DIR': set an explicit rpath.

     Added in version 3.10.


File: python.info,  Node: Security Options,  Next: macOS Options,  Prev: Libraries options,  Up: Configure Options

3.3.3.12 Security Options
.........................

 -- Option: --with-hash-algorithm=[fnv|siphash13|siphash24]

     Select hash algorithm for use in ‘Python/pyhash.c’:

        * ‘siphash13’ (default);

        * ‘siphash24’;

        * ‘fnv’.

     Added in version 3.4.

     Added in version 3.11: ‘siphash13’ is added and it is the new
     default.

 -- Option:
          --with-builtin-hashlib-hashes=md5,sha1,sha256,sha512,sha3,blake2

     Built-in hash modules:

        * ‘md5’;

        * ‘sha1’;

        * ‘sha256’;

        * ‘sha512’;

        * ‘sha3’ (with shake);

        * ‘blake2’.

     Added in version 3.9.

 -- Option: --with-ssl-default-suites=[python|openssl|STRING]

     Override the OpenSSL default cipher suites string:

        * ‘python’ (default): use Python’s preferred selection;

        * ‘openssl’: leave OpenSSL’s defaults untouched;

        * 'STRING': use a custom string

     See the *note ssl: d0. module.

     Added in version 3.7.

     Changed in version 3.10: The settings ‘python’ and 'STRING' also
     set TLS 1.2 as minimum protocol version.


File: python.info,  Node: macOS Options,  Next: iOS Options,  Prev: Security Options,  Up: Configure Options

3.3.3.13 macOS Options
......................

See Mac/README.rst(1).

 -- Option: --enable-universalsdk

 -- Option: --enable-universalsdk=SDKDIR

     Create a universal binary build.  'SDKDIR' specifies which macOS
     SDK should be used to perform the build (default is no).

 -- Option: --enable-framework

 -- Option: --enable-framework=INSTALLDIR

     Create a Python.framework rather than a traditional Unix install.
     Optional 'INSTALLDIR' specifies the installation path (default is
     no).

 -- Option: --with-universal-archs=ARCH

     Specify the kind of universal binary that should be created.  This
     option is only valid when *note -enable-universalsdk: 975. is set.

     Options:

        * ‘universal2’ (x86-64 and arm64);

        * ‘32-bit’ (PPC and i386);

        * ‘64-bit’ (PPC64 and x86-64);

        * ‘3-way’ (i386, PPC and x86-64);

        * ‘intel’ (i386 and x86-64);

        * ‘intel-32’ (i386);

        * ‘intel-64’ (x86-64);

        * ‘all’ (PPC, i386, PPC64 and x86-64).

     Note that values for this configuration item are 'not' the same as
     the identifiers used for universal binary wheels on macOS. See the
     Python Packaging User Guide for details on the packaging platform
     compatibility tags used on macOS(2)

 -- Option: --with-framework-name=FRAMEWORK

     Specify the name for the python framework on macOS only valid when
     *note -enable-framework: 1f6f. is set (default: ‘Python’).

 -- Option: --with-app-store-compliance

 -- Option: --with-app-store-compliance=PATCH-FILE

     The Python standard library contains strings that are known to
     trigger automated inspection tool errors when submitted for
     distribution by the macOS and iOS App Stores.  If enabled, this
     option will apply the list of patches that are known to correct app
     store compliance.  A custom patch file can also be specified.  This
     option is disabled by default.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Mac/README.rst

   (2) 
https://packaging.python.org/en/latest/specifications/platform-compatibility-tags/#macos


File: python.info,  Node: iOS Options,  Next: Cross Compiling Options,  Prev: macOS Options,  Up: Configure Options

3.3.3.14 iOS Options
....................

See iOS/README.rst(1).

 -- Option: --enable-framework=INSTALLDIR

     Create a Python.framework.  Unlike macOS, the 'INSTALLDIR' argument
     specifying the installation path is mandatory.

 -- Option: --with-framework-name=FRAMEWORK

     Specify the name for the framework (default: ‘Python’).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/iOS/README.rst


File: python.info,  Node: Cross Compiling Options,  Prev: iOS Options,  Up: Configure Options

3.3.3.15 Cross Compiling Options
................................

Cross compiling, also known as cross building, can be used to build
Python for another CPU architecture or platform.  Cross compiling
requires a Python interpreter for the build platform.  The version of
the build Python must match the version of the cross compiled host
Python.

 -- Option: --build=BUILD

     configure for building on BUILD, usually guessed by ‘config.guess’.

 -- Option: --host=HOST

     cross-compile to build programs to run on HOST (target platform)

 -- Option: --with-build-python=path/to/python

     path to build ‘python’ binary for cross compiling

     Added in version 3.11.

 -- Option: CONFIG_SITE=file

     An environment variable that points to a file with configure
     overrides.

     Example 'config.site' file:

          # config.site-aarch64
          ac_cv_buggy_getaddrinfo=no
          ac_cv_file__dev_ptmx=yes
          ac_cv_file__dev_ptc=no

 -- Option: HOSTRUNNER

     Program to run CPython for the host platform for cross-compilation.

     Added in version 3.11.

Cross compiling example:

     CONFIG_SITE=config.site-aarch64 ../configure \
         --build=x86_64-pc-linux-gnu \
         --host=aarch64-unknown-linux-gnu \
         --with-build-python=../x86_64/python


File: python.info,  Node: Python Build System,  Next: Compiler and linker flags,  Prev: Configure Options,  Up: Configure Python

3.3.4 Python Build System
-------------------------

* Menu:

* Main files of the build system::
* Main build steps::
* Main Makefile targets::
* C extensions::


File: python.info,  Node: Main files of the build system,  Next: Main build steps,  Up: Python Build System

3.3.4.1 Main files of the build system
......................................

   * ‘configure.ac’ => ‘configure’;

   * ‘Makefile.pre.in’ => ‘Makefile’ (created by ‘configure’);

   * ‘pyconfig.h’ (created by ‘configure’);

   * ‘Modules/Setup’: C extensions built by the Makefile using
     ‘Module/makesetup’ shell script;


File: python.info,  Node: Main build steps,  Next: Main Makefile targets,  Prev: Main files of the build system,  Up: Python Build System

3.3.4.2 Main build steps
........................

   * C files (‘.c’) are built as object files (‘.o’).

   * A static ‘libpython’ library (‘.a’) is created from objects files.

   * ‘python.o’ and the static ‘libpython’ library are linked into the
     final ‘python’ program.

   * C extensions are built by the Makefile (see ‘Modules/Setup’).


File: python.info,  Node: Main Makefile targets,  Next: C extensions,  Prev: Main build steps,  Up: Python Build System

3.3.4.3 Main Makefile targets
.............................

* Menu:

* make::
* make platform::
* make profile-opt::
* make clean::
* make distclean::
* make install::
* make test::
* make buildbottest::
* make regen-all::


File: python.info,  Node: make,  Next: make platform,  Up: Main Makefile targets

3.3.4.4 make
............

For the most part, when rebuilding after editing some code or refreshing
your checkout from upstream, all you need to do is execute ‘make’, which
(per Make’s semantics) builds the default target, the first one defined
in the Makefile.  By tradition (including in the CPython project) this
is usually the ‘all’ target.  The ‘configure’ script expands an
‘autoconf’ variable, ‘@DEF_MAKE_ALL_RULE@’ to describe precisely which
targets ‘make all’ will build.  The three choices are:

   * ‘profile-opt’ (configured with ‘--enable-optimizations’)

   * ‘build_wasm’ (configured with ‘--with-emscripten-target’)

   * ‘build_all’ (configured without explicitly using either of the
     others)

Depending on the most recent source file changes, Make will rebuild any
targets (object files and executables) deemed out-of-date, including
running ‘configure’ again if necessary.  Source/target dependencies are
many and maintained manually however, so Make sometimes doesn’t have all
the information necessary to correctly detect all targets which need to
be rebuilt.  Depending on which targets aren’t rebuilt, you might
experience a number of problems.  If you have build or test problems
which you can’t otherwise explain, ‘make clean && make’ should work
around most dependency problems, at the expense of longer build times.


File: python.info,  Node: make platform,  Next: make profile-opt,  Prev: make,  Up: Main Makefile targets

3.3.4.5 make platform
.....................

Build the ‘python’ program, but don’t build the standard library
extension modules.  This generates a file named ‘platform’ which
contains a single line describing the details of the build platform,
e.g., ‘macosx-14.3-arm64-3.12’ or ‘linux-x86_64-3.13’.


File: python.info,  Node: make profile-opt,  Next: make clean,  Prev: make platform,  Up: Main Makefile targets

3.3.4.6 make profile-opt
........................

Build Python using profile-guided optimization (PGO). You can use the
configure *note -enable-optimizations: 868. option to make this the
default target of the ‘make’ command (‘make all’ or just ‘make’).


File: python.info,  Node: make clean,  Next: make distclean,  Prev: make profile-opt,  Up: Main Makefile targets

3.3.4.7 make clean
..................

Remove built files.


File: python.info,  Node: make distclean,  Next: make install,  Prev: make clean,  Up: Main Makefile targets

3.3.4.8 make distclean
......................

In addition to the work done by ‘make clean’, remove files created by
the configure script.  ‘configure’ will have to be run before building
again.  (1)

   ---------- Footnotes ----------

   (1) ‘git clean -fdx’ is an even more extreme way to “clean” your
checkout.  It removes all files not known to Git.  When bug hunting
using ‘git bisect’, this is recommended between probes
(https://github.com/python/cpython/issues/114505#issuecomment-1907021718)
to guarantee a completely clean build.  'Use with care', as it will
delete all files not checked into Git, including your new, uncommitted
work.


File: python.info,  Node: make install,  Next: make test,  Prev: make distclean,  Up: Main Makefile targets

3.3.4.9 make install
....................

Build the ‘all’ target and install Python.


File: python.info,  Node: make test,  Next: make buildbottest,  Prev: make install,  Up: Main Makefile targets

3.3.4.10 make test
..................

Build the ‘all’ target and run the Python test suite with the
‘--fast-ci’ option.  Variables:

   * ‘TESTOPTS’: additional regrtest command-line options.

   * ‘TESTPYTHONOPTS’: additional Python command-line options.

   * ‘TESTTIMEOUT’: timeout in seconds (default: 10 minutes).


File: python.info,  Node: make buildbottest,  Next: make regen-all,  Prev: make test,  Up: Main Makefile targets

3.3.4.11 make buildbottest
..........................

This is similar to ‘make test’, but uses the ‘--slow-ci’ option and
default timeout of 20 minutes, instead of ‘--fast-ci’ option.


File: python.info,  Node: make regen-all,  Prev: make buildbottest,  Up: Main Makefile targets

3.3.4.12 make regen-all
.......................

Regenerate (almost) all generated files.  These include (but are not
limited to) bytecode cases, and parser generator file.  ‘make
regen-stdlib-module-names’ and ‘autoconf’ must be run separately for the
remaining *note generated files: 1f0f.


File: python.info,  Node: C extensions,  Prev: Main Makefile targets,  Up: Python Build System

3.3.4.13 C extensions
.....................

Some C extensions are built as built-in modules, like the ‘sys’ module.
They are built with the ‘Py_BUILD_CORE_BUILTIN’ macro defined.  Built-in
modules have no ‘__file__’ attribute:

     >>> import sys
     >>> sys
     <module 'sys' (built-in)>
     >>> sys.__file__
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     AttributeError: module 'sys' has no attribute '__file__'

Other C extensions are built as dynamic libraries, like the ‘_asyncio’
module.  They are built with the ‘Py_BUILD_CORE_MODULE’ macro defined.
Example on Linux x86-64:

     >>> import _asyncio
     >>> _asyncio
     <module '_asyncio' from '/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'>
     >>> _asyncio.__file__
     '/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'

‘Modules/Setup’ is used to generate Makefile targets to build C
extensions.  At the beginning of the files, C extensions are built as
built-in modules.  Extensions defined after the ‘*shared*’ marker are
built as dynamic libraries.

The ‘PyAPI_FUNC()’, ‘PyAPI_DATA()’ and *note PyMODINIT_FUNC: 1522.
macros of ‘Include/exports.h’ are defined differently depending if the
‘Py_BUILD_CORE_MODULE’ macro is defined:

   * Use ‘Py_EXPORTED_SYMBOL’ if the ‘Py_BUILD_CORE_MODULE’ is defined

   * Use ‘Py_IMPORTED_SYMBOL’ otherwise.

If the ‘Py_BUILD_CORE_BUILTIN’ macro is used by mistake on a C extension
built as a shared library, its ‘PyInit_XXX()’ function is not exported,
causing an *note ImportError: 41c. on import.


File: python.info,  Node: Compiler and linker flags,  Prev: Python Build System,  Up: Configure Python

3.3.5 Compiler and linker flags
-------------------------------

Options set by the ‘./configure’ script and environment variables and
used by ‘Makefile’.

* Menu:

* Preprocessor flags::
* Compiler flags::
* Linker flags::


File: python.info,  Node: Preprocessor flags,  Next: Compiler flags,  Up: Compiler and linker flags

3.3.5.1 Preprocessor flags
..........................

 -- Environment Variable: CONFIGURE_CPPFLAGS

     Value of *note CPPFLAGS: 1508. variable passed to the ‘./configure’
     script.

     Added in version 3.6.

 -- Environment Variable: CPPFLAGS

     (Objective) C/C++ preprocessor flags, e.g.  ‘-IINCLUDE_DIR’ if you
     have headers in a nonstandard directory 'include_dir'.

     Both *note CPPFLAGS: 1508. and *note LDFLAGS: 1507. need to contain
     the shell’s value to be able to build extension modules using the
     directories specified in the environment variables.

 -- Environment Variable: BASECPPFLAGS

     Added in version 3.4.

 -- Environment Variable: PY_CPPFLAGS

     Extra preprocessor flags added for building the interpreter object
     files.

     Default: ‘$(BASECPPFLAGS) -I. -I$(srcdir)/Include
     $(CONFIGURE_CPPFLAGS) $(CPPFLAGS)’.

     Added in version 3.2.


File: python.info,  Node: Compiler flags,  Next: Linker flags,  Prev: Preprocessor flags,  Up: Compiler and linker flags

3.3.5.2 Compiler flags
......................

 -- Environment Variable: CC

     C compiler command.

     Example: ‘gcc -pthread’.

 -- Environment Variable: CXX

     C++ compiler command.

     Example: ‘g++ -pthread’.

 -- Environment Variable: CFLAGS

     C compiler flags.

 -- Environment Variable: CFLAGS_NODIST

     *note CFLAGS_NODIST: 1f92. is used for building the interpreter and
     stdlib C extensions.  Use it when a compiler flag should 'not' be
     part of *note CFLAGS: 1506. once Python is installed (gh-65320(1)).

     In particular, *note CFLAGS: 1506. should not contain:

        * the compiler flag ‘-I’ (for setting the search path for
          include files).  The ‘-I’ flags are processed from left to
          right, and any flags in *note CFLAGS: 1506. would take
          precedence over user- and package-supplied ‘-I’ flags.

        * hardening flags such as ‘-Werror’ because distributions cannot
          control whether packages installed by users conform to such
          heightened standards.

     Added in version 3.5.

 -- Environment Variable: COMPILEALL_OPTS

     Options passed to the *note compileall: 20. command line when
     building PYC files in ‘make install’.  Default: ‘-j0’.

     Added in version 3.12.

 -- Environment Variable: EXTRA_CFLAGS

     Extra C compiler flags.

 -- Environment Variable: CONFIGURE_CFLAGS

     Value of *note CFLAGS: 1506. variable passed to the ‘./configure’
     script.

     Added in version 3.2.

 -- Environment Variable: CONFIGURE_CFLAGS_NODIST

     Value of *note CFLAGS_NODIST: 1f92. variable passed to the
     ‘./configure’ script.

     Added in version 3.5.

 -- Environment Variable: BASECFLAGS

     Base compiler flags.

 -- Environment Variable: OPT

     Optimization flags.

 -- Environment Variable: CFLAGS_ALIASING

     Strict or non-strict aliasing flags used to compile
     ‘Python/dtoa.c’.

     Added in version 3.7.

 -- Environment Variable: CCSHARED

     Compiler flags used to build a shared library.

     For example, ‘-fPIC’ is used on Linux and on BSD.

 -- Environment Variable: CFLAGSFORSHARED

     Extra C flags added for building the interpreter object files.

     Default: ‘$(CCSHARED)’ when *note -enable-shared: 869. is used, or
     an empty string otherwise.

 -- Environment Variable: PY_CFLAGS

     Default: ‘$(BASECFLAGS) $(OPT) $(CONFIGURE_CFLAGS) $(CFLAGS)
     $(EXTRA_CFLAGS)’.

 -- Environment Variable: PY_CFLAGS_NODIST

     Default: ‘$(CONFIGURE_CFLAGS_NODIST) $(CFLAGS_NODIST)
     -I$(srcdir)/Include/internal’.

     Added in version 3.5.

 -- Environment Variable: PY_STDMODULE_CFLAGS

     C flags used for building the interpreter object files.

     Default: ‘$(PY_CFLAGS) $(PY_CFLAGS_NODIST) $(PY_CPPFLAGS)
     $(CFLAGSFORSHARED)’.

     Added in version 3.7.

 -- Environment Variable: PY_CORE_CFLAGS

     Default: ‘$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE’.

     Added in version 3.2.

 -- Environment Variable: PY_BUILTIN_MODULE_CFLAGS

     Compiler flags to build a standard library extension module as a
     built-in module, like the *note posix: ad. module.

     Default: ‘$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE_BUILTIN’.

     Added in version 3.8.

 -- Environment Variable: PURIFY

     Purify command.  Purify is a memory debugger program.

     Default: empty string (not used).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/65320


File: python.info,  Node: Linker flags,  Prev: Compiler flags,  Up: Compiler and linker flags

3.3.5.3 Linker flags
....................

 -- Environment Variable: LINKCC

     Linker command used to build programs like ‘python’ and
     ‘_testembed’.

     Default: ‘$(PURIFY) $(CC)’.

 -- Environment Variable: CONFIGURE_LDFLAGS

     Value of *note LDFLAGS: 1507. variable passed to the ‘./configure’
     script.

     Avoid assigning *note CFLAGS: 1506, *note LDFLAGS: 1507, etc.  so
     users can use them on the command line to append to these values
     without stomping the pre-set values.

     Added in version 3.2.

 -- Environment Variable: LDFLAGS_NODIST

     *note LDFLAGS_NODIST: 1fa4. is used in the same manner as *note
     CFLAGS_NODIST: 1f92.  Use it when a linker flag should 'not' be
     part of *note LDFLAGS: 1507. once Python is installed
     (gh-65320(1)).

     In particular, *note LDFLAGS: 1507. should not contain:

        * the compiler flag ‘-L’ (for setting the search path for
          libraries).  The ‘-L’ flags are processed from left to right,
          and any flags in *note LDFLAGS: 1507. would take precedence
          over user- and package-supplied ‘-L’ flags.

 -- Environment Variable: CONFIGURE_LDFLAGS_NODIST

     Value of *note LDFLAGS_NODIST: 1fa4. variable passed to the
     ‘./configure’ script.

     Added in version 3.8.

 -- Environment Variable: LDFLAGS

     Linker flags, e.g.  ‘-LLIB_DIR’ if you have libraries in a
     nonstandard directory 'lib_dir'.

     Both *note CPPFLAGS: 1508. and *note LDFLAGS: 1507. need to contain
     the shell’s value to be able to build extension modules using the
     directories specified in the environment variables.

 -- Environment Variable: LIBS

     Linker flags to pass libraries to the linker when linking the
     Python executable.

     Example: ‘-lrt’.

 -- Environment Variable: LDSHARED

     Command to build a shared library.

     Default: ‘@LDSHARED@ $(PY_LDFLAGS)’.

 -- Environment Variable: BLDSHARED

     Command to build ‘libpython’ shared library.

     Default: ‘@BLDSHARED@ $(PY_CORE_LDFLAGS)’.

 -- Environment Variable: PY_LDFLAGS

     Default: ‘$(CONFIGURE_LDFLAGS) $(LDFLAGS)’.

 -- Environment Variable: PY_LDFLAGS_NODIST

     Default: ‘$(CONFIGURE_LDFLAGS_NODIST) $(LDFLAGS_NODIST)’.

     Added in version 3.8.

 -- Environment Variable: PY_CORE_LDFLAGS

     Linker flags used for building the interpreter object files.

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/65320


File: python.info,  Node: Using Python on Windows,  Next: Using Python on macOS,  Prev: Configure Python,  Up: Python Setup and Usage

3.4 Using Python on Windows
===========================

This document aims to give an overview of Windows-specific behaviour you
should know about when using Python on Microsoft Windows.

Unlike most Unix systems and services, Windows does not include a system
supported installation of Python.  To make Python available, the CPython
team has compiled Windows installers with every release(1) for many
years.  These installers are primarily intended to add a per-user
installation of Python, with the core interpreter and library being used
by a single user.  The installer is also able to install for all users
of a single machine, and a separate ZIP file is available for
application-local distributions.

As specified in PEP 11(2), a Python release only supports a Windows
platform while Microsoft considers the platform under extended support.
This means that Python 3.13 supports Windows 8.1 and newer.  If you
require Windows 7 support, please install Python 3.8.

There are a number of different installers available for Windows, each
with certain benefits and downsides.

*note The full installer: 1faf. contains all components and is the best
option for developers using Python for any kind of project.

*note The Microsoft Store package: 1d7a. is a simple installation of
Python that is suitable for running scripts and packages, and using IDLE
or other development environments.  It requires Windows 10 and above,
but can be safely installed without corrupting other programs.  It also
provides many convenient commands for launching Python and its tools.

*note The nuget.org packages: 1fb0. are lightweight installations
intended for continuous integration systems.  It can be used to build
Python packages or run scripts, but is not updateable and has no user
interface tools.

*note The embeddable package: 1fb1. is a minimal package of Python
suitable for embedding into a larger application.

* Menu:

* The full installer::
* The Microsoft Store package::
* The nuget.org packages: The nuget org packages.
* The embeddable package::
* Alternative bundles::
* Configuring Python::
* UTF-8 mode::
* Python Launcher for Windows::
* Finding modules::
* Additional modules::
* Compiling Python on Windows::
* Other Platforms::

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/

   (2) https://peps.python.org/pep-0011/


File: python.info,  Node: The full installer,  Next: The Microsoft Store package,  Up: Using Python on Windows

3.4.1 The full installer
------------------------

* Menu:

* Installation steps::
* Removing the MAX_PATH Limitation::
* Installing Without UI::
* Installing Without Downloading::
* Modifying an install::
* Installing Free-threaded Binaries::


File: python.info,  Node: Installation steps,  Next: Removing the MAX_PATH Limitation,  Up: The full installer

3.4.1.1 Installation steps
..........................

Four Python 3.13 installers are available for download - two each for
the 32-bit and 64-bit versions of the interpreter.  The 'web installer'
is a small initial download, and it will automatically download the
required components as necessary.  The 'offline installer' includes the
components necessary for a default installation and only requires an
internet connection for optional features.  See *note Installing Without
Downloading: 1fb4. for other ways to avoid downloading during
installation.

After starting the installer, one of two options may be selected:

[image src="python-figures/win_installer.png"]


If you select “Install Now”:

   * You will 'not' need to be an administrator (unless a system update
     for the C Runtime Library is required or you install the *note
     Python Launcher for Windows: 5c1. for all users)

   * Python will be installed into your user directory

   * The *note Python Launcher for Windows: 5c1. will be installed
     according to the option at the bottom of the first page

   * The standard library, test suite, launcher and pip will be
     installed

   * If selected, the install directory will be added to your ‘PATH’

   * Shortcuts will only be visible for the current user

Selecting “Customize installation” will allow you to select the features
to install, the installation location and other options or post-install
actions.  To install debugging symbols or binaries, you will need to use
this option.

To perform an all-users installation, you should select “Customize
installation”.  In this case:

   * You may be required to provide administrative credentials or
     approval

   * Python will be installed into the Program Files directory

   * The *note Python Launcher for Windows: 5c1. will be installed into
     the Windows directory

   * Optional features may be selected during installation

   * The standard library can be pre-compiled to bytecode

   * If selected, the install directory will be added to the system
     ‘PATH’

   * Shortcuts are available for all users


File: python.info,  Node: Removing the MAX_PATH Limitation,  Next: Installing Without UI,  Prev: Installation steps,  Up: The full installer

3.4.1.2 Removing the MAX_PATH Limitation
........................................

Windows historically has limited path lengths to 260 characters.  This
meant that paths longer than this would not resolve and errors would
result.

In the latest versions of Windows, this limitation can be expanded to
approximately 32,000 characters.  Your administrator will need to
activate the “Enable Win32 long paths” group policy, or set
‘LongPathsEnabled’ to ‘1’ in the registry key
‘HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem’.

This allows the *note open(): 51f. function, the *note os: a1. module
and most other path functionality to accept and return paths longer than
260 characters.

After changing the above option, no further configuration is required.

Changed in version 3.6: Support for long paths was enabled in Python.


File: python.info,  Node: Installing Without UI,  Next: Installing Without Downloading,  Prev: Removing the MAX_PATH Limitation,  Up: The full installer

3.4.1.3 Installing Without UI
.............................

All of the options available in the installer UI can also be specified
from the command line, allowing scripted installers to replicate an
installation on many machines without user interaction.  These options
may also be set without suppressing the UI in order to change some of
the defaults.

The following options (found by executing the installer with ‘/?’) can
be passed into the installer:

Name                      Description
                          
---------------------------------------------------------------------------------------
                          
/passive                  to display progress without requiring user interaction
                          
                          
/quiet                    to install/uninstall without displaying any UI
                          
                          
/simple                   to prevent user customization
                          
                          
/uninstall                to remove Python (without confirmation)
                          
                          
/layout [directory]       to pre-download all components
                          
                          
/log [filename]           to specify log files location
                          

All other options are passed as ‘name=value’, where the value is usually
‘0’ to disable a feature, ‘1’ to enable a feature, or a path.  The full
list of available options is shown below.

Name                            Description                                Default
                                                                           
----------------------------------------------------------------------------------------------------------
                                                                           
InstallAllUsers                 Perform a system-wide installation.        0
                                                                           
                                                                           
TargetDir                       The installation directory                 Selected based on
                                                                           InstallAllUsers
                                                                           
                                                                           
DefaultAllUsersTargetDir        The default installation directory for     ‘%ProgramFiles%\Python X.Y’
                                all-user installs                          or
                                                                           ‘%ProgramFiles(x86)%\Python
                                                                           X.Y’
                                                                           
                                                                           
DefaultJustForMeTargetDir       The default install directory for          ‘%LocalAppData%\Programs\Python\PythonXY’
                                just-for-me installs                       or
                                                                           ‘%LocalAppData%\Programs\Python\PythonXY-32’
                                                                           or
                                                                           ‘%LocalAppData%\Programs\Python\PythonXY-64’
                                                                           
                                                                           
DefaultCustomTargetDir          The default custom install directory       (empty)
                                displayed in the UI                        
                                
                                                                           
AssociateFiles                  Create file associations if the launcher   1
                                is also installed.                         
                                
                                                                           
CompileAll                      Compile all ‘.py’ files to ‘.pyc’.         0
                                                                           
                                                                           
PrependPath                     Prepend install and Scripts directories    0
                                to ‘PATH’ and add ‘.PY’ to ‘PATHEXT’       
                                
                                                                           
AppendPath                      Append install and Scripts directories     0
                                to ‘PATH’ and add ‘.PY’ to ‘PATHEXT’       
                                
                                                                           
Shortcuts                       Create shortcuts for the interpreter,      1
                                documentation and IDLE if installed.       
                                
                                                                           
Include_doc                     Install Python manual                      1
                                                                           
                                                                           
Include_debug                   Install debug binaries                     0
                                                                           
                                                                           
Include_dev                     Install developer headers and libraries.   1
                                Omitting this may lead to an unusable      
                                installation.
                                
                                                                           
Include_exe                     Install ‘python.exe’ and related files.    1
                                Omitting this may lead to an unusable      
                                installation.
                                
                                                                           
Include_launcher                Install                                    1
                                *note Python Launcher for Windows: 5c1.    
                                
                                                                           
InstallLauncherAllUsers         Installs the launcher for all users.       1
                                Also requires ‘Include_launcher’ to be     
                                set to 1
                                
                                                                           
Include_lib                     Install standard library and extension     1
                                modules.  Omitting this may lead to an     
                                unusable installation.
                                
                                                                           
Include_pip                     Install bundled pip and setuptools         1
                                                                           
                                                                           
Include_symbols                 Install debugging symbols (‘*.pdb’)        0
                                                                           
                                                                           
Include_tcltk                   Install Tcl/Tk support and IDLE            1
                                                                           
                                                                           
Include_test                    Install standard library test suite        1
                                                                           
                                                                           
Include_tools                   Install utility scripts                    1
                                                                           
                                                                           
LauncherOnly                    Only installs the launcher.  This will     0
                                override most other options.               
                                
                                                                           
SimpleInstall                   Disable most install UI                    0
                                                                           
                                                                           
SimpleInstallDescription        A custom message to display when the       (empty)
                                simplified install UI is used.             
                                

For example, to silently install a default, system-wide Python
installation, you could use the following command (from an elevated
command prompt):

     python-3.9.0.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0

To allow users to easily install a personal copy of Python without the
test suite, you could provide a shortcut with the following command.
This will display a simplified initial page and disallow customization:

     python-3.9.0.exe InstallAllUsers=0 Include_launcher=0 Include_test=0
         SimpleInstall=1 SimpleInstallDescription="Just for me, no test suite."

(Note that omitting the launcher also omits file associations, and is
only recommended for per-user installs when there is also a system-wide
installation that included the launcher.)

The options listed above can also be provided in a file named
‘unattend.xml’ alongside the executable.  This file specifies a list of
options and values.  When a value is provided as an attribute, it will
be converted to a number if possible.  Values provided as element text
are always left as strings.  This example file sets the same options as
the previous example:

     <Options>
         <Option Name="InstallAllUsers" Value="no" />
         <Option Name="Include_launcher" Value="0" />
         <Option Name="Include_test" Value="no" />
         <Option Name="SimpleInstall" Value="yes" />
         <Option Name="SimpleInstallDescription">Just for me, no test suite</Option>
     </Options>


File: python.info,  Node: Installing Without Downloading,  Next: Modifying an install,  Prev: Installing Without UI,  Up: The full installer

3.4.1.4 Installing Without Downloading
......................................

As some features of Python are not included in the initial installer
download, selecting those features may require an internet connection.
To avoid this need, all possible components may be downloaded on-demand
to create a complete 'layout' that will no longer require an internet
connection regardless of the selected features.  Note that this download
may be bigger than required, but where a large number of installations
are going to be performed it is very useful to have a locally cached
copy.

Execute the following command from Command Prompt to download all
possible required files.  Remember to substitute ‘python-3.9.0.exe’ for
the actual name of your installer, and to create layouts in their own
directories to avoid collisions between files with the same name.

     python-3.9.0.exe /layout [optional target directory]

You may also specify the ‘/quiet’ option to hide the progress display.


File: python.info,  Node: Modifying an install,  Next: Installing Free-threaded Binaries,  Prev: Installing Without Downloading,  Up: The full installer

3.4.1.5 Modifying an install
............................

Once Python has been installed, you can add or remove features through
the Programs and Features tool that is part of Windows.  Select the
Python entry and choose “Uninstall/Change” to open the installer in
maintenance mode.

“Modify” allows you to add or remove features by modifying the
checkboxes - unchanged checkboxes will not install or remove anything.
Some options cannot be changed in this mode, such as the install
directory; to modify these, you will need to remove and then reinstall
Python completely.

“Repair” will verify all the files that should be installed using the
current settings and replace any that have been removed or modified.

“Uninstall” will remove Python entirely, with the exception of the *note
Python Launcher for Windows: 5c1, which has its own entry in Programs
and Features.


File: python.info,  Node: Installing Free-threaded Binaries,  Prev: Modifying an install,  Up: The full installer

3.4.1.6 Installing Free-threaded Binaries
.........................................

Added in version 3.13: (Experimental)

     Note: Everything described in this section is considered
     experimental, and should be expected to change in future releases.

To install pre-built binaries with free-threading enabled (see PEP
703(1)), you should select “Customize installation”.  The second page of
options includes the “Download free-threaded binaries” checkbox.

[image src="python-figures/win_install_freethreaded.png"]


Selecting this option will download and install additional binaries to
the same location as the main Python install.  The main executable is
called ‘python3.13t.exe’, and other binaries either receive a ‘t’ suffix
or a full ABI suffix.  Python source files and bundled third-party
dependencies are shared with the main install.

The free-threaded version is registered as a regular Python install with
the tag ‘3.13t’ (with a ‘-32’ or ‘-arm64’ suffix as normal for those
platforms).  This allows tools to discover it, and for the *note Python
Launcher for Windows: 5c1. to support ‘py.exe -3.13t’.  Note that the
launcher will interpret ‘py.exe -3’ (or a ‘python3’ shebang) as “the
latest 3.x install”, which will prefer the free-threaded binaries over
the regular ones, while ‘py.exe -3.13’ will not.  If you use the short
style of option, you may prefer to not install the free-threaded
binaries at this time.

To specify the install option at the command line, use
‘Include_freethreaded=1’.  See *note Installing Without Downloading:
1fb4. for instructions on pre-emptively downloading the additional
binaries for offline install.  The options to include debug symbols and
binaries also apply to the free-threaded builds.

Free-threaded binaries are also available *note on nuget.org: 1fb0.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/


File: python.info,  Node: The Microsoft Store package,  Next: The nuget org packages,  Prev: The full installer,  Up: Using Python on Windows

3.4.2 The Microsoft Store package
---------------------------------

Added in version 3.7.2.

The Microsoft Store package is an easily installable Python interpreter
that is intended mainly for interactive use, for example, by students.

To install the package, ensure you have the latest Windows 10 updates
and search the Microsoft Store app for “Python 3.13”.  Ensure that the
app you select is published by the Python Software Foundation, and
install it.

     Warning: Python will always be available for free on the Microsoft
     Store.  If you are asked to pay for it, you have not selected the
     correct package.

After installation, Python may be launched by finding it in Start.
Alternatively, it will be available from any Command Prompt or
PowerShell session by typing ‘python’.  Further, pip and IDLE may be
used by typing ‘pip’ or ‘idle’.  IDLE can also be found in Start.

All three commands are also available with version number suffixes, for
example, as ‘python3.exe’ and ‘python3.x.exe’ as well as ‘python.exe’
(where ‘3.x’ is the specific version you want to launch, such as 3.13).
Open “Manage App Execution Aliases” through Start to select which
version of Python is associated with each command.  It is recommended to
make sure that ‘pip’ and ‘idle’ are consistent with whichever version of
‘python’ is selected.

Virtual environments can be created with ‘python -m venv’ and activated
and used as normal.

If you have installed another version of Python and added it to your
‘PATH’ variable, it will be available as ‘python.exe’ rather than the
one from the Microsoft Store.  To access the new installation, use
‘python3.exe’ or ‘python3.x.exe’.

The ‘py.exe’ launcher will detect this Python installation, but will
prefer installations from the traditional installer.

To remove Python, open Settings and use Apps and Features, or else find
Python in Start and right-click to select Uninstall.  Uninstalling will
remove all packages you installed directly into this Python
installation, but will not remove any virtual environments

* Menu:

* Known issues::


File: python.info,  Node: Known issues,  Up: The Microsoft Store package

3.4.2.1 Known issues
....................

* Menu:

* Redirection of local data, registry, and temporary paths: Redirection of local data registry and temporary paths.


File: python.info,  Node: Redirection of local data registry and temporary paths,  Up: Known issues

3.4.2.2 Redirection of local data, registry, and temporary paths
................................................................

Because of restrictions on Microsoft Store apps, Python scripts may not
have full write access to shared locations such as ‘TEMP’ and the
registry.  Instead, it will write to a private copy.  If your scripts
must modify the shared locations, you will need to install the full
installer.

At runtime, Python will use a private copy of well-known Windows folders
and the registry.  For example, if the environment variable ‘%APPDATA%’
is ‘c:\Users\<user>\AppData\’, then when writing to
‘C:\Users\<user>\AppData\Local’ will write to
‘C:\Users\<user>\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.8_qbz5n2kfra8p0\LocalCache\Local\’.

When reading files, Windows will return the file from the private
folder, or if that does not exist, the real Windows directory.  For
example reading ‘C:\Windows\System32’ returns the contents of
‘C:\Windows\System32’ plus the contents of ‘C:\Program
Files\WindowsApps\package_name\VFS\SystemX86’.

You can find the real path of any existing file using *note
os.path.realpath(): 225.:

     >>> import os
     >>> test_file = 'C:\\Users\\example\\AppData\\Local\\test.txt'
     >>> os.path.realpath(test_file)
     'C:\\Users\\example\\AppData\\Local\\Packages\\PythonSoftwareFoundation.Python.3.8_qbz5n2kfra8p0\\LocalCache\\Local\\test.txt'

When writing to the Windows Registry, the following behaviors exist:

   * Reading from ‘HKLM\\Software’ is allowed and results are merged
     with the ‘registry.dat’ file in the package.

   * Writing to ‘HKLM\\Software’ is not allowed if the corresponding
     key/value exists, i.e.  modifying existing keys.

   * Writing to ‘HKLM\\Software’ is allowed as long as a corresponding
     key/value does not exist in the package and the user has the
     correct access permissions.

For more detail on the technical basis for these limitations, please
consult Microsoft’s documentation on packaged full-trust apps, currently
available at
docs.microsoft.com/en-us/windows/msix/desktop/desktop-to-uwp-behind-the-scenes(1)

   ---------- Footnotes ----------

   (1) 
https://learn.microsoft.com/windows/msix/desktop/desktop-to-uwp-behind-the-scenes


File: python.info,  Node: The nuget org packages,  Next: The embeddable package,  Prev: The Microsoft Store package,  Up: Using Python on Windows

3.4.3 The nuget.org packages
----------------------------

Added in version 3.5.2.

The nuget.org package is a reduced size Python environment intended for
use on continuous integration and build systems that do not have a
system-wide install of Python.  While nuget is “the package manager for
.NET”, it also works perfectly fine for packages containing build-time
tools.

Visit nuget.org(1) for the most up-to-date information on using nuget.
What follows is a summary that is sufficient for Python developers.

The ‘nuget.exe’ command line tool may be downloaded directly from
‘https://aka.ms/nugetclidl’, for example, using curl or PowerShell.
With the tool, the latest version of Python for 64-bit or 32-bit
machines is installed using:

     nuget.exe install python -ExcludeVersion -OutputDirectory .
     nuget.exe install pythonx86 -ExcludeVersion -OutputDirectory .

To select a particular version, add a ‘-Version 3.x.y’.  The output
directory may be changed from ‘.’, and the package will be installed
into a subdirectory.  By default, the subdirectory is named the same as
the package, and without the ‘-ExcludeVersion’ option this name will
include the specific version installed.  Inside the subdirectory is a
‘tools’ directory that contains the Python installation:

     # Without -ExcludeVersion
     > .\python.3.5.2\tools\python.exe -V
     Python 3.5.2

     # With -ExcludeVersion
     > .\python\tools\python.exe -V
     Python 3.5.2

In general, nuget packages are not upgradeable, and newer versions
should be installed side-by-side and referenced using the full path.
Alternatively, delete the package directory manually and install it
again.  Many CI systems will do this automatically if they do not
preserve files between builds.

Alongside the ‘tools’ directory is a ‘build\native’ directory.  This
contains a MSBuild properties file ‘python.props’ that can be used in a
C++ project to reference the Python install.  Including the settings
will automatically use the headers and import libraries in your build.

The package information pages on nuget.org are
www.nuget.org/packages/python(2) for the 64-bit version,
www.nuget.org/packages/pythonx86(3) for the 32-bit version, and
www.nuget.org/packages/pythonarm64(4) for the ARM64 version

* Menu:

* Free-threaded packages::

   ---------- Footnotes ----------

   (1) https://www.nuget.org/

   (2) https://www.nuget.org/packages/python

   (3) https://www.nuget.org/packages/pythonx86

   (4) https://www.nuget.org/packages/pythonarm64


File: python.info,  Node: Free-threaded packages,  Up: The nuget org packages

3.4.3.1 Free-threaded packages
..............................

Added in version 3.13: (Experimental)

     Note: Everything described in this section is considered
     experimental, and should be expected to change in future releases.

Packages containing free-threaded binaries are named
python-freethreaded(1) for the 64-bit version, pythonx86-freethreaded(2)
for the 32-bit version, and pythonarm64-freethreaded(3) for the ARM64
version.  These packages contain both the ‘python3.13t.exe’ and
‘python.exe’ entry points, both of which run free threaded.

   ---------- Footnotes ----------

   (1) https://www.nuget.org/packages/python-freethreaded

   (2) https://www.nuget.org/packages/pythonx86-freethreaded

   (3) https://www.nuget.org/packages/pythonarm64-freethreaded


File: python.info,  Node: The embeddable package,  Next: Alternative bundles,  Prev: The nuget org packages,  Up: Using Python on Windows

3.4.4 The embeddable package
----------------------------

Added in version 3.5.

The embedded distribution is a ZIP file containing a minimal Python
environment.  It is intended for acting as part of another application,
rather than being directly accessed by end-users.

When extracted, the embedded distribution is (almost) fully isolated
from the user’s system, including environment variables, system registry
settings, and installed packages.  The standard library is included as
pre-compiled and optimized ‘.pyc’ files in a ZIP, and ‘python3.dll’,
‘python37.dll’, ‘python.exe’ and ‘pythonw.exe’ are all provided.  Tcl/tk
(including all dependents, such as Idle), pip and the Python
documentation are not included.

     Note: The embedded distribution does not include the Microsoft C
     Runtime(1) and it is the responsibility of the application
     installer to provide this.  The runtime may have already been
     installed on a user’s system previously or automatically via
     Windows Update, and can be detected by finding ‘ucrtbase.dll’ in
     the system directory.

Third-party packages should be installed by the application installer
alongside the embedded distribution.  Using pip to manage dependencies
as for a regular Python installation is not supported with this
distribution, though with some care it may be possible to include and
use pip for automatic updates.  In general, third-party packages should
be treated as part of the application (“vendoring”) so that the
developer can ensure compatibility with newer versions before providing
updates to users.

The two recommended use cases for this distribution are described below.

* Menu:

* Python Application::
* Embedding Python::

   ---------- Footnotes ----------

   (1) 
https://learn.microsoft.com/cpp/windows/latest-supported-vc-redist#visual-studio-2015-2017-2019-and-2022


File: python.info,  Node: Python Application,  Next: Embedding Python,  Up: The embeddable package

3.4.4.1 Python Application
..........................

An application written in Python does not necessarily require users to
be aware of that fact.  The embedded distribution may be used in this
case to include a private version of Python in an install package.
Depending on how transparent it should be (or conversely, how
professional it should appear), there are two options.

Using a specialized executable as a launcher requires some coding, but
provides the most transparent experience for users.  With a customized
launcher, there are no obvious indications that the program is running
on Python: icons can be customized, company and version information can
be specified, and file associations behave properly.  In most cases, a
custom launcher should simply be able to call ‘Py_Main’ with a
hard-coded command line.

The simpler approach is to provide a batch file or generated shortcut
that directly calls the ‘python.exe’ or ‘pythonw.exe’ with the required
command-line arguments.  In this case, the application will appear to be
Python and not its actual name, and users may have trouble
distinguishing it from other running Python processes or file
associations.

With the latter approach, packages should be installed as directories
alongside the Python executable to ensure they are available on the
path.  With the specialized launcher, packages can be located in other
locations as there is an opportunity to specify the search path before
launching the application.


File: python.info,  Node: Embedding Python,  Prev: Python Application,  Up: The embeddable package

3.4.4.2 Embedding Python
........................

Applications written in native code often require some form of scripting
language, and the embedded Python distribution can be used for this
purpose.  In general, the majority of the application is in native code,
and some part will either invoke ‘python.exe’ or directly use
‘python3.dll’.  For either case, extracting the embedded distribution to
a subdirectory of the application installation is sufficient to provide
a loadable Python interpreter.

As with the application use, packages can be installed to any location
as there is an opportunity to specify search paths before initializing
the interpreter.  Otherwise, there is no fundamental differences between
using the embedded distribution and a regular installation.


File: python.info,  Node: Alternative bundles,  Next: Configuring Python,  Prev: The embeddable package,  Up: Using Python on Windows

3.4.5 Alternative bundles
-------------------------

Besides the standard CPython distribution, there are modified packages
including additional functionality.  The following is a list of popular
versions and their key features:

ActivePython(1)

     Installer with multi-platform compatibility, documentation, PyWin32

Anaconda(2)

     Popular scientific modules (such as numpy, scipy and pandas) and
     the ‘conda’ package manager.

Enthought Deployment Manager(3)

     “The Next Generation Python Environment and Package Manager”.

     Previously Enthought provided Canopy, but it reached end of life in
     2016(4).

WinPython(5)

     Windows-specific distribution with prebuilt scientific packages and
     tools for building packages.

Note that these packages may not include the latest versions of Python
or other libraries, and are not maintained or supported by the core
Python team.

   ---------- Footnotes ----------

   (1) https://www.activestate.com/products/python/

   (2) https://www.anaconda.com/download/

   (3) https://assets.enthought.com/downloads/edm/

   (4) 
https://support.enthought.com/hc/en-us/articles/360038600051-Canopy-GUI-end-of-life-transition-to-the-Enthought-Deployment-Manager-EDM-and-Visual-Studio-Code

   (5) https://winpython.github.io/


File: python.info,  Node: Configuring Python,  Next: UTF-8 mode,  Prev: Alternative bundles,  Up: Using Python on Windows

3.4.6 Configuring Python
------------------------

To run Python conveniently from a command prompt, you might consider
changing some default environment variables in Windows.  While the
installer provides an option to configure the PATH and PATHEXT variables
for you, this is only reliable for a single, system-wide installation.
If you regularly use multiple versions of Python, consider using the
*note Python Launcher for Windows: 5c1.

* Menu:

* Excursus; Setting environment variables: Excursus Setting environment variables.
* Finding the Python executable::


File: python.info,  Node: Excursus Setting environment variables,  Next: Finding the Python executable,  Up: Configuring Python

3.4.6.1 Excursus: Setting environment variables
...............................................

Windows allows environment variables to be configured permanently at
both the User level and the System level, or temporarily in a command
prompt.

To temporarily set environment variables, open Command Prompt and use
the ‘set’ command:

     C:\>set PATH=C:\Program Files\Python 3.9;%PATH%
     C:\>set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib
     C:\>python

These changes will apply to any further commands executed in that
console, and will be inherited by any applications started from the
console.

Including the variable name within percent signs will expand to the
existing value, allowing you to add your new value at either the start
or the end.  Modifying ‘PATH’ by adding the directory containing
‘python.exe’ to the start is a common way to ensure the correct version
of Python is launched.

To permanently modify the default environment variables, click Start and
search for ‘edit environment variables’, or open System properties,
Advanced system settings and click the Environment Variables button.  In
this dialog, you can add or modify User and System variables.  To change
System variables, you need non-restricted access to your machine (i.e.
Administrator rights).

     Note: Windows will concatenate User variables 'after' System
     variables, which may cause unexpected results when modifying
     ‘PATH’.

     The *note PYTHONPATH: 1058. variable is used by all versions of
     Python, so you should not permanently configure it unless the
     listed paths only include code that is compatible with all of your
     installed Python versions.

See also
........

‘https://learn.microsoft.com/windows/win32/procthread/environment-variables’

     Overview of environment variables on Windows

‘https://learn.microsoft.com/windows-server/administration/windows-commands/set_1’

     The ‘set’ command, for temporarily modifying environment variables

‘https://learn.microsoft.com/windows-server/administration/windows-commands/setx’

     The ‘setx’ command, for permanently modifying environment variables


File: python.info,  Node: Finding the Python executable,  Prev: Excursus Setting environment variables,  Up: Configuring Python

3.4.6.2 Finding the Python executable
.....................................

Changed in version 3.5.

Besides using the automatically created start menu entry for the Python
interpreter, you might want to start Python in the command prompt.  The
installer has an option to set that up for you.

On the first page of the installer, an option labelled “Add Python to
PATH” may be selected to have the installer add the install location
into the ‘PATH’.  The location of the ‘Scripts\’ folder is also added.
This allows you to type ‘python’ to run the interpreter, and ‘pip’ for
the package installer.  Thus, you can also execute your scripts with
command line options, see *note Command line: 1042. documentation.

If you don’t enable this option at install time, you can always re-run
the installer, select Modify, and enable it.  Alternatively, you can
manually modify the ‘PATH’ using the directions in *note Excursus;
Setting environment variables: 1d7b.  You need to set your ‘PATH’
environment variable to include the directory of your Python
installation, delimited by a semicolon from other entries.  An example
variable could look like this (assuming the first two entries already
existed):

     C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Python 3.9


File: python.info,  Node: UTF-8 mode,  Next: Python Launcher for Windows,  Prev: Configuring Python,  Up: Using Python on Windows

3.4.7 UTF-8 mode
----------------

Added in version 3.7.

Windows still uses legacy encodings for the system encoding (the ANSI
Code Page).  Python uses it for the default encoding of text files (e.g.
*note locale.getencoding(): 2dc.).

This may cause issues because UTF-8 is widely used on the internet and
most Unix systems, including WSL (Windows Subsystem for Linux).

You can use the *note Python UTF-8 Mode: 659. to change the default text
encoding to UTF-8.  You can enable the *note Python UTF-8 Mode: 659. via
the ‘-X utf8’ command line option, or the ‘PYTHONUTF8=1’ environment
variable.  See *note PYTHONUTF8: aee. for enabling UTF-8 mode, and *note
Excursus; Setting environment variables: 1d7b. for how to modify
environment variables.

When the *note Python UTF-8 Mode: 659. is enabled, you can still use the
system encoding (the ANSI Code Page) via the “mbcs” codec.

Note that adding ‘PYTHONUTF8=1’ to the default environment variables
will affect all Python 3.7+ applications on your system.  If you have
any Python 3.7+ applications which rely on the legacy system encoding,
it is recommended to set the environment variable temporarily or use the
‘-X utf8’ command line option.

     Note: Even when UTF-8 mode is disabled, Python uses UTF-8 by
     default on Windows for:

        * Console I/O including standard I/O (see PEP 528(1) for
          details).

        * The *note filesystem encoding: 53e. (see PEP 529(2) for
          details).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0528/

   (2) https://peps.python.org/pep-0529/


File: python.info,  Node: Python Launcher for Windows,  Next: Finding modules,  Prev: UTF-8 mode,  Up: Using Python on Windows

3.4.8 Python Launcher for Windows
---------------------------------

Added in version 3.3.

The Python launcher for Windows is a utility which aids in locating and
executing of different Python versions.  It allows scripts (or the
command-line) to indicate a preference for a specific Python version,
and will locate and execute that version.

Unlike the ‘PATH’ variable, the launcher will correctly select the most
appropriate version of Python.  It will prefer per-user installations
over system-wide ones, and orders by language version rather than using
the most recently installed version.

The launcher was originally specified in PEP 397(1).

* Menu:

* Getting started::
* Shebang Lines::
* Arguments in shebang lines::
* Customization::
* Diagnostics::
* Dry Run::
* Install on demand::
* Return codes::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0397/


File: python.info,  Node: Getting started,  Next: Shebang Lines,  Up: Python Launcher for Windows

3.4.8.1 Getting started
.......................

* Menu:

* From the command-line::
* Virtual environments::
* From a script::
* From file associations::


File: python.info,  Node: From the command-line,  Next: Virtual environments,  Up: Getting started

3.4.8.2 From the command-line
.............................

Changed in version 3.6.

System-wide installations of Python 3.3 and later will put the launcher
on your ‘PATH’.  The launcher is compatible with all available versions
of Python, so it does not matter which version is installed.  To check
that the launcher is available, execute the following command in Command
Prompt:

     py

You should find that the latest version of Python you have installed is
started - it can be exited as normal, and any additional command-line
arguments specified will be sent directly to Python.

If you have multiple versions of Python installed (e.g., 3.7 and 3.13)
you will have noticed that Python 3.13 was started - to launch Python
3.7, try the command:

     py -3.7

If you want the latest version of Python 2 you have installed, try the
command:

     py -2

If you see the following error, you do not have the launcher installed:

     'py' is not recognized as an internal or external command,
     operable program or batch file.

The command:

     py --list

displays the currently installed version(s) of Python.

The ‘-x.y’ argument is the short form of the ‘-V:Company/Tag’ argument,
which allows selecting a specific Python runtime, including those that
may have come from somewhere other than python.org.  Any runtime
registered by following PEP 514(1) will be discoverable.  The ‘--list’
command lists all available runtimes using the ‘-V:’ format.

When using the ‘-V:’ argument, specifying the Company will limit
selection to runtimes from that provider, while specifying only the Tag
will select from all providers.  Note that omitting the slash implies a
tag:

     # Select any '3.*' tagged runtime
     py -V:3

     # Select any 'PythonCore' released runtime
     py -V:PythonCore/

     # Select PythonCore's latest Python 3 runtime
     py -V:PythonCore/3

The short form of the argument (‘-3’) only ever selects from core Python
releases, and not other distributions.  However, the longer form
(‘-V:3’) will select from any.

The Company is matched on the full string, case-insensitive.  The Tag is
matched on either the full string, or a prefix, provided the next
character is a dot or a hyphen.  This allows ‘-V:3.1’ to match ‘3.1-32’,
but not ‘3.10’.  Tags are sorted using numerical ordering (‘3.10’ is
newer than ‘3.1’), but are compared using text (‘-V:3.01’ does not match
‘3.1’).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0514/


File: python.info,  Node: Virtual environments,  Next: From a script,  Prev: From the command-line,  Up: Getting started

3.4.8.3 Virtual environments
............................

Added in version 3.5.

If the launcher is run with no explicit Python version specification,
and a virtual environment (created with the standard library *note venv:
111. module or the external ‘virtualenv’ tool) active, the launcher will
run the virtual environment’s interpreter rather than the global one.
To run the global interpreter, either deactivate the virtual
environment, or explicitly specify the global Python version.


File: python.info,  Node: From a script,  Next: From file associations,  Prev: Virtual environments,  Up: Getting started

3.4.8.4 From a script
.....................

Let’s create a test Python script - create a file called ‘hello.py’ with
the following contents

     #! python
     import sys
     sys.stdout.write("hello from Python %s\n" % (sys.version,))

From the directory in which hello.py lives, execute the command:

     py hello.py

You should notice the version number of your latest Python 2.x
installation is printed.  Now try changing the first line to be:

     #! python3

Re-executing the command should now print the latest Python 3.x
information.  As with the above command-line examples, you can specify a
more explicit version qualifier.  Assuming you have Python 3.7
installed, try changing the first line to ‘#! python3.7’ and you should
find the 3.7 version information printed.

Note that unlike interactive use, a bare “python” will use the latest
version of Python 2.x that you have installed.  This is for backward
compatibility and for compatibility with Unix, where the command
‘python’ typically refers to Python 2.


File: python.info,  Node: From file associations,  Prev: From a script,  Up: Getting started

3.4.8.5 From file associations
..............................

The launcher should have been associated with Python files (i.e.  ‘.py’,
‘.pyw’, ‘.pyc’ files) when it was installed.  This means that when you
double-click on one of these files from Windows explorer the launcher
will be used, and therefore you can use the same facilities described
above to have the script specify the version which should be used.

The key benefit of this is that a single launcher can support multiple
Python versions at the same time depending on the contents of the first
line.


File: python.info,  Node: Shebang Lines,  Next: Arguments in shebang lines,  Prev: Getting started,  Up: Python Launcher for Windows

3.4.8.6 Shebang Lines
.....................

If the first line of a script file starts with ‘#!’, it is known as a
“shebang” line.  Linux and other Unix like operating systems have native
support for such lines and they are commonly used on such systems to
indicate how a script should be executed.  This launcher allows the same
facilities to be used with Python scripts on Windows and the examples
above demonstrate their use.

To allow shebang lines in Python scripts to be portable between Unix and
Windows, this launcher supports a number of ‘virtual’ commands to
specify which interpreter to use.  The supported virtual commands are:

   * ‘/usr/bin/env’

   * ‘/usr/bin/python’

   * ‘/usr/local/bin/python’

   * ‘python’

For example, if the first line of your script starts with

     #! /usr/bin/python

The default Python or an active virtual environment will be located and
used.  As many Python scripts written to work on Unix will already have
this line, you should find these scripts can be used by the launcher
without modification.  If you are writing a new script on Windows which
you hope will be useful on Unix, you should use one of the shebang lines
starting with ‘/usr’.

Any of the above virtual commands can be suffixed with an explicit
version (either just the major version, or the major and minor version).
Furthermore the 32-bit version can be requested by adding “-32” after
the minor version.  I.e.  ‘/usr/bin/python3.7-32’ will request usage of
the 32-bit Python 3.7.  If a virtual environment is active, the version
will be ignored and the environment will be used.

Added in version 3.7: Beginning with python launcher 3.7 it is possible
to request 64-bit version by the “-64” suffix.  Furthermore it is
possible to specify a major and architecture without minor (i.e.
‘/usr/bin/python3-64’).

Changed in version 3.11: The “-64” suffix is deprecated, and now implies
“any architecture that is not provably i386/32-bit”.  To request a
specific environment, use the new ‘-V:TAG’ argument with the complete
tag.

Changed in version 3.13: Virtual commands referencing ‘python’ now
prefer an active virtual environment rather than searching ‘PATH’.  This
handles cases where the shebang specifies ‘/usr/bin/env python3’ but
‘python3.exe’ is not present in the active environment.

The ‘/usr/bin/env’ form of shebang line has one further special
property.  Before looking for installed Python interpreters, this form
will search the executable ‘PATH’ for a Python executable matching the
name provided as the first argument.  This corresponds to the behaviour
of the Unix ‘env’ program, which performs a ‘PATH’ search.  If an
executable matching the first argument after the ‘env’ command cannot be
found, but the argument starts with ‘python’, it will be handled as
described for the other virtual commands.  The environment variable
‘PYLAUNCHER_NO_SEARCH_PATH’ may be set (to any value) to skip this
search of ‘PATH’.

Shebang lines that do not match any of these patterns are looked up in
the ‘[commands]’ section of the launcher’s *note .INI file: 1fcf.  This
may be used to handle certain commands in a way that makes sense for
your system.  The name of the command must be a single argument (no
spaces in the shebang executable), and the value substituted is the full
path to the executable (additional arguments specified in the .INI will
be quoted as part of the filename).

     [commands]
     /bin/xpython=C:\Program Files\XPython\python.exe

Any commands not found in the .INI file are treated as 'Windows'
executable paths that are absolute or relative to the directory
containing the script file.  This is a convenience for Windows-only
scripts, such as those generated by an installer, since the behavior is
not compatible with Unix-style shells.  These paths may be quoted, and
may include multiple arguments, after which the path to the script and
any additional arguments will be appended.


File: python.info,  Node: Arguments in shebang lines,  Next: Customization,  Prev: Shebang Lines,  Up: Python Launcher for Windows

3.4.8.7 Arguments in shebang lines
..................................

The shebang lines can also specify additional options to be passed to
the Python interpreter.  For example, if you have a shebang line:

     #! /usr/bin/python -v

Then Python will be started with the ‘-v’ option


File: python.info,  Node: Customization,  Next: Diagnostics,  Prev: Arguments in shebang lines,  Up: Python Launcher for Windows

3.4.8.8 Customization
.....................

* Menu:

* Customization via INI files::
* Customizing default Python versions::


File: python.info,  Node: Customization via INI files,  Next: Customizing default Python versions,  Up: Customization

3.4.8.9 Customization via INI files
...................................

Two .ini files will be searched by the launcher - ‘py.ini’ in the
current user’s application data directory (‘%LOCALAPPDATA%’ or
‘$env:LocalAppData’) and ‘py.ini’ in the same directory as the launcher.
The same .ini files are used for both the ‘console’ version of the
launcher (i.e.  py.exe) and for the ‘windows’ version (i.e.  pyw.exe).

Customization specified in the “application directory” will have
precedence over the one next to the executable, so a user, who may not
have write access to the .ini file next to the launcher, can override
commands in that global .ini file.


File: python.info,  Node: Customizing default Python versions,  Prev: Customization via INI files,  Up: Customization

3.4.8.10 Customizing default Python versions
............................................

In some cases, a version qualifier can be included in a command to
dictate which version of Python will be used by the command.  A version
qualifier starts with a major version number and can optionally be
followed by a period (‘.’) and a minor version specifier.  Furthermore
it is possible to specify if a 32 or 64 bit implementation shall be
requested by adding “-32” or “-64”.

For example, a shebang line of ‘#!python’ has no version qualifier,
while ‘#!python3’ has a version qualifier which specifies only a major
version.

If no version qualifiers are found in a command, the environment
variable ‘PY_PYTHON’ can be set to specify the default version
qualifier.  If it is not set, the default is “3”.  The variable can
specify any value that may be passed on the command line, such as “3”,
“3.7”, “3.7-32” or “3.7-64”.  (Note that the “-64” option is only
available with the launcher included with Python 3.7 or newer.)

If no minor version qualifiers are found, the environment variable
‘PY_PYTHON{major}’ (where ‘{major}’ is the current major version
qualifier as determined above) can be set to specify the full version.
If no such option is found, the launcher will enumerate the installed
Python versions and use the latest minor release found for the major
version, which is likely, although not guaranteed, to be the most
recently installed version in that family.

On 64-bit Windows with both 32-bit and 64-bit implementations of the
same (major.minor) Python version installed, the 64-bit version will
always be preferred.  This will be true for both 32-bit and 64-bit
implementations of the launcher - a 32-bit launcher will prefer to
execute a 64-bit Python installation of the specified version if
available.  This is so the behavior of the launcher can be predicted
knowing only what versions are installed on the PC and without regard to
the order in which they were installed (i.e., without knowing whether a
32 or 64-bit version of Python and corresponding launcher was installed
last).  As noted above, an optional “-32” or “-64” suffix can be used on
a version specifier to change this behaviour.

Examples:

   * If no relevant options are set, the commands ‘python’ and ‘python2’
     will use the latest Python 2.x version installed and the command
     ‘python3’ will use the latest Python 3.x installed.

   * The command ‘python3.7’ will not consult any options at all as the
     versions are fully specified.

   * If ‘PY_PYTHON=3’, the commands ‘python’ and ‘python3’ will both use
     the latest installed Python 3 version.

   * If ‘PY_PYTHON=3.7-32’, the command ‘python’ will use the 32-bit
     implementation of 3.7 whereas the command ‘python3’ will use the
     latest installed Python (PY_PYTHON was not considered at all as a
     major version was specified.)

   * If ‘PY_PYTHON=3’ and ‘PY_PYTHON3=3.7’, the commands ‘python’ and
     ‘python3’ will both use specifically 3.7

In addition to environment variables, the same settings can be
configured in the .INI file used by the launcher.  The section in the
INI file is called ‘[defaults]’ and the key name will be the same as the
environment variables without the leading ‘PY_’ prefix (and note that
the key names in the INI file are case insensitive.)  The contents of an
environment variable will override things specified in the INI file.

For example:

   * Setting ‘PY_PYTHON=3.7’ is equivalent to the INI file containing:

     [defaults]
     python=3.7

   * Setting ‘PY_PYTHON=3’ and ‘PY_PYTHON3=3.7’ is equivalent to the INI
     file containing:

     [defaults]
     python=3
     python3=3.7


File: python.info,  Node: Diagnostics,  Next: Dry Run,  Prev: Customization,  Up: Python Launcher for Windows

3.4.8.11 Diagnostics
....................

If an environment variable ‘PYLAUNCHER_DEBUG’ is set (to any value), the
launcher will print diagnostic information to stderr (i.e.  to the
console).  While this information manages to be simultaneously verbose
'and' terse, it should allow you to see what versions of Python were
located, why a particular version was chosen and the exact command-line
used to execute the target Python.  It is primarily intended for testing
and debugging.


File: python.info,  Node: Dry Run,  Next: Install on demand,  Prev: Diagnostics,  Up: Python Launcher for Windows

3.4.8.12 Dry Run
................

If an environment variable ‘PYLAUNCHER_DRYRUN’ is set (to any value),
the launcher will output the command it would have run, but will not
actually launch Python.  This may be useful for tools that want to use
the launcher to detect and then launch Python directly.  Note that the
command written to standard output is always encoded using UTF-8, and
may not render correctly in the console.


File: python.info,  Node: Install on demand,  Next: Return codes,  Prev: Dry Run,  Up: Python Launcher for Windows

3.4.8.13 Install on demand
..........................

If an environment variable ‘PYLAUNCHER_ALLOW_INSTALL’ is set (to any
value), and the requested Python version is not installed but is
available on the Microsoft Store, the launcher will attempt to install
it.  This may require user interaction to complete, and you may need to
run the command again.

An additional ‘PYLAUNCHER_ALWAYS_INSTALL’ variable causes the launcher
to always try to install Python, even if it is detected.  This is mainly
intended for testing (and should be used with ‘PYLAUNCHER_DRYRUN’).


File: python.info,  Node: Return codes,  Prev: Install on demand,  Up: Python Launcher for Windows

3.4.8.14 Return codes
.....................

The following exit codes may be returned by the Python launcher.
Unfortunately, there is no way to distinguish these from the exit code
of Python itself.

The names of codes are as used in the sources, and are only for
reference.  There is no way to access or resolve them apart from reading
this page.  Entries are listed in alphabetical order of names.

Name                    Value       Description
                                    
----------------------------------------------------------------------------------------
                                    
RC_BAD_VENV_CFG         107         A ‘pyvenv.cfg’ was found but is corrupt.
                                    
                                    
RC_CREATE_PROCESS       101         Failed to launch Python.
                                    
                                    
RC_INSTALLING           111         An install was started, but the command will need
                                    to be re-run after it completes.
                                    
                                    
RC_INTERNAL_ERROR       109         Unexpected error.  Please report a bug.
                                    
                                    
RC_NO_COMMANDLINE       108         Unable to obtain command line from the operating
                                    system.
                                    
                                    
RC_NO_PYTHON            103         Unable to locate the requested version.
                                    
                                    
RC_NO_VENV_CFG          106         A ‘pyvenv.cfg’ was required but not found.
                                    


File: python.info,  Node: Finding modules,  Next: Additional modules,  Prev: Python Launcher for Windows,  Up: Using Python on Windows

3.4.9 Finding modules
---------------------

These notes supplement the description at *note The initialization of
the sys.path module search path: 1dfe. with detailed Windows notes.

When no ‘._pth’ file is found, this is how *note sys.path: 3b7. is
populated on Windows:

   * An empty entry is added at the start, which corresponds to the
     current directory.

   * If the environment variable *note PYTHONPATH: 1058. exists, as
     described in *note Environment variables: 5f4, its entries are
     added next.  Note that on Windows, paths in this variable must be
     separated by semicolons, to distinguish them from the colon used in
     drive identifiers (‘C:\’ etc.).

   * Additional “application paths” can be added in the registry as
     subkeys of ‘\SOFTWARE\Python\PythonCore{version}\PythonPath’ under
     both the ‘HKEY_CURRENT_USER’ and ‘HKEY_LOCAL_MACHINE’ hives.
     Subkeys which have semicolon-delimited path strings as their
     default value will cause each path to be added to *note sys.path:
     3b7.  (Note that all known installers only use HKLM, so HKCU is
     typically empty.)

   * If the environment variable *note PYTHONHOME: 3bf. is set, it is
     assumed as “Python Home”.  Otherwise, the path of the main Python
     executable is used to locate a “landmark file” (either ‘Lib\os.py’
     or ‘pythonXY.zip’) to deduce the “Python Home”.  If a Python home
     is found, the relevant sub-directories added to *note sys.path:
     3b7. (‘Lib’, ‘plat-win’, etc) are based on that folder.  Otherwise,
     the core Python path is constructed from the PythonPath stored in
     the registry.

   * If the Python Home cannot be located, no *note PYTHONPATH: 1058. is
     specified in the environment, and no registry entries can be found,
     a default path with relative entries is used (e.g.
     ‘.\Lib;.\plat-win’, etc).

If a ‘pyvenv.cfg’ file is found alongside the main executable or in the
directory one level above the executable, the following variations
apply:

   * If ‘home’ is an absolute path and *note PYTHONHOME: 3bf. is not
     set, this path is used instead of the path to the main executable
     when deducing the home location.

The end result of all this is:

   * When running ‘python.exe’, or any other .exe in the main Python
     directory (either an installed version, or directly from the
     PCbuild directory), the core path is deduced, and the core paths in
     the registry are ignored.  Other “application paths” in the
     registry are always read.

   * When Python is hosted in another .exe (different directory,
     embedded via COM, etc), the “Python Home” will not be deduced, so
     the core path from the registry is used.  Other “application paths”
     in the registry are always read.

   * If Python can’t find its home and there are no registry value
     (frozen .exe, some very strange installation setup) you get a path
     with some default, but relative, paths.

For those who want to bundle Python into their application or
distribution, the following advice will prevent conflicts with other
installations:

   * Include a ‘._pth’ file alongside your executable containing the
     directories to include.  This will ignore paths listed in the
     registry and environment variables, and also ignore *note site: c7.
     unless ‘import site’ is listed.

   * If you are loading ‘python3.dll’ or ‘python37.dll’ in your own
     executable, explicitly set *note PyConfig.module_search_paths: 3a5.
     before *note Py_InitializeFromConfig(): 3c8.

   * Clear and/or overwrite *note PYTHONPATH: 1058. and set *note
     PYTHONHOME: 3bf. before launching ‘python.exe’ from your
     application.

   * If you cannot use the previous suggestions (for example, you are a
     distribution that allows people to run ‘python.exe’ directly),
     ensure that the landmark file (‘Lib\os.py’) exists in your install
     directory.  (Note that it will not be detected inside a ZIP file,
     but a correctly named ZIP file will be detected instead.)

These will ensure that the files in a system-wide installation will not
take precedence over the copy of the standard library bundled with your
application.  Otherwise, your users may experience problems using your
application.  Note that the first suggestion is the best, as the others
may still be susceptible to non-standard paths in the registry and user
site-packages.

Changed in version 3.6: Add ‘._pth’ file support and removes ‘applocal’
option from ‘pyvenv.cfg’.

Changed in version 3.6: Add ‘python`XX'.zip’ as a potential landmark
when directly adjacent to the executable.

Deprecated since version 3.6: Modules specified in the registry under
‘Modules’ (not ‘PythonPath’) may be imported by *note
importlib.machinery.WindowsRegistryFinder: d52.  This finder is enabled
on Windows in 3.6.0 and earlier, but may need to be explicitly added to
*note sys.meta_path: d53. in the future.


File: python.info,  Node: Additional modules,  Next: Compiling Python on Windows,  Prev: Finding modules,  Up: Using Python on Windows

3.4.10 Additional modules
-------------------------

Even though Python aims to be portable among all platforms, there are
features that are unique to Windows.  A couple of modules, both in the
standard library and external, and snippets exist to use these features.

The Windows-specific standard modules are documented in *note MS Windows
Specific Services: 1fda.

* Menu:

* PyWin32::
* cx_Freeze::


File: python.info,  Node: PyWin32,  Next: cx_Freeze,  Up: Additional modules

3.4.10.1 PyWin32
................

The PyWin32(1) module by Mark Hammond is a collection of modules for
advanced Windows-specific support.  This includes utilities for:

   * Component Object Model(2) (COM)

   * Win32 API calls

   * Registry

   * Event log

   * Microsoft Foundation Classes(3) (MFC) user interfaces

PythonWin(4) is a sample MFC application shipped with PyWin32.  It is an
embeddable IDE with a built-in debugger.

See also
........

Win32 How Do I...?(5)

     by Tim Golden

Python and COM(6)

     by David and Paul Boddie

   ---------- Footnotes ----------

   (1) https://pypi.org/project/PyWin32/

   (2) 
https://learn.microsoft.com/windows/win32/com/component-object-model-com-portal

   (3) https://learn.microsoft.com/cpp/mfc/mfc-desktop-applications

   (4) 
https://web.archive.org/web/20060524042422/https://www.python.org/windows/pythonwin/

   (5) https://timgolden.me.uk/python/win32_how_do_i.html

   (6) https://www.boddie.org.uk/python/COM.html


File: python.info,  Node: cx_Freeze,  Prev: PyWin32,  Up: Additional modules

3.4.10.2 cx_Freeze
..................

cx_Freeze(1) wraps Python scripts into executable Windows programs
(‘`*'.exe’ files).  When you have done this, you can distribute your
application without requiring your users to install Python.

   ---------- Footnotes ----------

   (1) https://cx-freeze.readthedocs.io/en/latest/


File: python.info,  Node: Compiling Python on Windows,  Next: Other Platforms,  Prev: Additional modules,  Up: Using Python on Windows

3.4.11 Compiling Python on Windows
----------------------------------

If you want to compile CPython yourself, first thing you should do is
get the source(1).  You can download either the latest release’s source
or just grab a fresh checkout(2).

The source tree contains a build solution and project files for
Microsoft Visual Studio, which is the compiler used to build the
official Python releases.  These files are in the ‘PCbuild’ directory.

Check ‘PCbuild/readme.txt’ for general information on the build process.

For extension modules, consult *note Building C and C++ Extensions on
Windows: 1fde.

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/source/

   (2) https://devguide.python.org/setup/#get-the-source-code


File: python.info,  Node: Other Platforms,  Prev: Compiling Python on Windows,  Up: Using Python on Windows

3.4.12 Other Platforms
----------------------

With ongoing development of Python, some platforms that used to be
supported earlier are no longer supported (due to the lack of users or
developers).  Check PEP 11(1) for details on all unsupported platforms.

   * Windows CE(2) is no longer supported(3) since Python 3 (if it ever
     was).

   * The Cygwin(4) installer offers to install the Python interpreter(5)
     as well

See Python for Windows(6) for detailed information about platforms with
pre-compiled installers.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0011/

   (2) https://pythonce.sourceforge.net/

   (3) https://github.com/python/cpython/issues/71542

   (4) https://cygwin.com/

   (5) https://cygwin.com/packages/summary/python3.html

   (6) https://www.python.org/downloads/windows/


File: python.info,  Node: Using Python on macOS,  Next: Using Python on Android,  Prev: Using Python on Windows,  Up: Python Setup and Usage

3.5 Using Python on macOS
=========================

This document aims to give an overview of macOS-specific behavior you
should know about to get started with Python on Mac computers.  Python
on a Mac running macOS is very similar to Python on other Unix-derived
platforms, but there are some differences in installation and some
features.

There are various ways to obtain and install Python for macOS. Pre-built
versions of the most recent versions of Python are available from a
number of distributors.  Much of this document describes use of the
Pythons provided by the CPython release team for download from the
python.org website(1).  See *note Alternative Distributions: 1fe4. for
some other options.
* Menu:

* Using Python for macOS from python.org: Using Python for macOS from python org.
* Alternative Distributions::
* Installing Additional Python Packages::
* GUI Programming::
* Advanced Topics::
* Other Resources::

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/


File: python.info,  Node: Using Python for macOS from python org,  Next: Alternative Distributions,  Up: Using Python on macOS

3.5.1 Using Python for macOS from ‘python.org’
----------------------------------------------

* Menu:

* Installation steps: Installation steps<2>.
* How to run a Python script::


File: python.info,  Node: Installation steps<2>,  Next: How to run a Python script,  Up: Using Python for macOS from python org

3.5.1.1 Installation steps
..........................

For current Python versions(1) (other than those in ‘security’ status),
the release team produces a 'Python for macOS' installer package for
each new release.  A list of available installers is available here(2).
We recommend using the most recent supported Python version where
possible.  Current installers provide a universal2 binary(3) build of
Python which runs natively on all Macs (Apple Silicon and Intel) that
are supported by a wide range of macOS versions, currently typically
from at least 'macOS 10.13 High Sierra' on.

The downloaded file is a standard macOS installer package file (‘.pkg’).
File integrity information (checksum, size, sigstore signature, etc) for
each file is included on the release download page.  Installer packages
and their contents are signed and notarized with ‘Python Software
Foundation’ Apple Developer ID certificates to meet macOS Gatekeeper
requirements(4).

For a default installation, double-click on the downloaded installer
package file.  This should launch the standard macOS Installer app and
display the first of several installer windows steps.

[image src="python-figures/mac_installer_01_introduction.png"]


Clicking on the 'Continue' button brings up the 'Read Me' for this
installer.  Besides other important information, the 'Read Me' documents
which Python version is going to be installed and on what versions of
macOS it is supported.  You may need to scroll through to read the whole
file.  By default, this 'Read Me' will also be installed in
‘/Applications/Python 3.13/’ and available to read anytime.

[image src="python-figures/mac_installer_02_readme.png"]


Clicking on 'Continue' proceeds to display the license for Python and
for other included software.  You will then need to 'Agree' to the
license terms before proceeding to the next step.  This license file
will also be installed and available to be read later.

[image src="python-figures/mac_installer_03_license.png"]


After the license terms are accepted, the next step is the 'Installation
Type' display.  For most uses, the standard set of installation
operations is appropriate.

[image src="python-figures/mac_installer_04_installation_type.png"]


By pressing the 'Customize' button, you can choose to omit or select
certain package components of the installer.  Click on each package name
to see a description of what it installs.  To also install support for
the optional experimental free-threaded feature, see *note Installing
Free-threaded Binaries: 173.

[image src="python-figures/mac_installer_05_custom_install.png"]


In either case, clicking 'Install' will begin the install process by
asking permission to install new software.  A macOS user name with
‘Administrator’ privilege is needed as the installed Python will be
available to all users of the Mac.

When the installation is complete, the 'Summary' window will appear.

[image src="python-figures/mac_installer_06_summary.png"]


Double-click on the ‘Install Certificates.command’ icon or file in the
‘/Applications/Python 3.13/’ window to complete the installation.

[image src="python-figures/mac_installer_07_applications.png"]


This will open a temporary ‘Terminal’ shell window that will use the new
Python to download and install SSL root certificates for its use.

[image src="python-figures/mac_installer_08_install_certificates.png"]


If ‘Successfully installed certifi’ and ‘update complete’ appears in the
terminal window, the installation is complete.  Close this terminal
window and the installer window.

A default install will include:

   * A ‘Python 3.13’ folder in your ‘Applications’ folder.  In here you
     find ‘IDLE’, the development environment that is a standard part of
     official Python distributions; and ‘Python Launcher’, which handles
     double-clicking Python scripts from the macOS Finder(5).

   * A framework ‘/Library/Frameworks/Python.framework’, which includes
     the Python executable and libraries.  The installer adds this
     location to your shell path.  To uninstall Python, you can remove
     these three things.  Symlinks to the Python executable are placed
     in ‘/usr/local/bin/’.

     Note: Recent versions of macOS include a ‘python3’ command in
     ‘/usr/bin/python3’ that links to a usually older and incomplete
     version of Python provided by and for use by the Apple development
     tools, ‘Xcode’ or the ‘Command Line Tools for Xcode’.  You should
     never modify or attempt to delete this installation, as it is
     Apple-controlled and is used by Apple-provided or third-party
     software.  If you choose to install a newer Python version from
     ‘python.org’, you will have two different but functional Python
     installations on your computer that can co-exist.  The default
     installer options should ensure that its ‘python3’ will be used
     instead of the system ‘python3’.

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/

   (2) https://www.python.org/downloads/macos/

   (3) https://en.wikipedia.org/wiki/Universal_binary

   (4) https://support.apple.com/en-us/102445

   (5) https://support.apple.com/en-us/HT201732


File: python.info,  Node: How to run a Python script,  Prev: Installation steps<2>,  Up: Using Python for macOS from python org

3.5.1.2 How to run a Python script
..................................

There are two ways to invoke the Python interpreter.  If you are
familiar with using a Unix shell in a terminal window, you can invoke
‘python3.13’ or ‘python3’ optionally followed by one or more command
line options (described in *note Command line and environment: 1b4f.).
The Python tutorial also has a useful section on *note using Python
interactively from a shell: 16f.

You can also invoke the interpreter through an integrated development
environment.  *note IDLE — Python editor and shell: 1050. is a basic
editor and interpreter environment which is included with the standard
distribution of Python.  ‘IDLE’ includes a Help menu that allows you to
access Python documentation.  If you are completely new to Python, you
can read the tutorial introduction in that document.

There are many other editors and IDEs available, see *note Editors and
IDEs: 1fea. for more information.

To run a Python script file from the terminal window, you can invoke the
interpreter with the name of the script file:

     ‘python3.13’ ‘myscript.py’

To run your script from the Finder, you can either:

   * Drag it to ‘Python Launcher’.

   * Select ‘Python Launcher’ as the default application to open your
     script (or any ‘.py’ script) through the Finder Info window and
     double-click it.  ‘Python Launcher’ has various preferences to
     control how your script is launched.  Option-dragging allows you to
     change these for one invocation, or use its ‘Preferences’ menu to
     change things globally.

Be aware that running the script directly from the macOS Finder might
produce different results than when running from a terminal window as
the script will not be run in the usual shell environment including any
setting of environment variables in shell profiles.  And, as with any
other script or program, be certain of what you are about to run.


File: python.info,  Node: Alternative Distributions,  Next: Installing Additional Python Packages,  Prev: Using Python for macOS from python org,  Up: Using Python on macOS

3.5.2 Alternative Distributions
-------------------------------

Besides the standard ‘python.org’ for macOS installer, there are
third-party distributions for macOS that may include additional
functionality.  Some popular distributions and their key features:

ActivePython(1)

     Installer with multi-platform compatibility, documentation

Anaconda(2)

     Popular scientific modules (such as numpy, scipy, and pandas) and
     the ‘conda’ package manager.

Homebrew(3)

     Package manager for macOS including multiple versions of Python and
     many third-party Python-based packages (including numpy, scipy, and
     pandas).

MacPorts(4)

     Another package manager for macOS including multiple versions of
     Python and many third-party Python-based packages.  May include
     pre-built versions of Python and many packages for older versions
     of macOS.

Note that distributions might not include the latest versions of Python
or other libraries, and are not maintained or supported by the core
Python team.

   ---------- Footnotes ----------

   (1) https://www.activestate.com/products/python/

   (2) https://www.anaconda.com/download/

   (3) https://brew.sh

   (4) https://www.macports.org


File: python.info,  Node: Installing Additional Python Packages,  Next: GUI Programming,  Prev: Alternative Distributions,  Up: Using Python on macOS

3.5.3 Installing Additional Python Packages
-------------------------------------------

Refer to the Python Packaging User Guide(1) for more information.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/tutorials/installing-packages/


File: python.info,  Node: GUI Programming,  Next: Advanced Topics,  Prev: Installing Additional Python Packages,  Up: Using Python on macOS

3.5.4 GUI Programming
---------------------

There are several options for building GUI applications on the Mac with
Python.

The standard Python GUI toolkit is *note tkinter: f0, based on the
cross-platform Tk toolkit (‘https://www.tcl.tk’).  A macOS-native
version of Tk is included with the installer.

'PyObjC' is a Python binding to Apple’s Objective-C/Cocoa framework.
Information on PyObjC is available from pyobjc(1).

A number of alternative macOS GUI toolkits are available including:

   * PySide(2): Official Python bindings to the Qt GUI toolkit(3).

   * PyQt(4): Alternative Python bindings to Qt.

   * Kivy(5): A cross-platform GUI toolkit that supports desktop and
     mobile platforms.

   * Toga(6): Part of the BeeWare Project(7); supports desktop, mobile,
     web and console apps.

   * wxPython(8): A cross-platform toolkit that supports desktop
     operating systems.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/pyobjc/

   (2) https://www.qt.io/qt-for-python

   (3) https://wiki.qt.io/Qt_for_Python

   (4) https://riverbankcomputing.com/software/pyqt/

   (5) https://kivy.org

   (6) https://toga.readthedocs.io

   (7) https://beeware.org

   (8) https://wxpython.org


File: python.info,  Node: Advanced Topics,  Next: Other Resources,  Prev: GUI Programming,  Up: Using Python on macOS

3.5.5 Advanced Topics
---------------------

* Menu:

* Installing Free-threaded Binaries: Installing Free-threaded Binaries<2>.
* Installing using the command line::
* Distributing Python Applications::
* App Store Compliance::


File: python.info,  Node: Installing Free-threaded Binaries<2>,  Next: Installing using the command line,  Up: Advanced Topics

3.5.5.1 Installing Free-threaded Binaries
.........................................

Added in version 3.13: (Experimental)

     Note: Everything described in this section is considered
     experimental, and should be expected to change in future releases.

The ‘python.org’ *note Python for macOS: 1fe6. installer package can
optionally install an additional build of Python 3.13 that supports PEP
703(1), the experimental free-threading feature (running with the *note
global interpreter lock: 148. disabled).  Check the release page on
‘python.org’ for possible updated information.

Because this feature is still considered experimental, the support for
it is not installed by default.  It is packaged as a separate install
option, available by clicking the 'Customize' button on the
'Installation Type' step of the installer as described above.

[image src="python-figures/mac_installer_09_custom_install_free_threaded.png"]


If the box next to the 'Free-threaded Python' package name is checked, a
separate ‘PythonT.framework’ will also be installed alongside the normal
‘Python.framework’ in ‘/Library/Frameworks’.  This configuration allows
a free-threaded Python 3.13 build to co-exist on your system with a
traditional (GIL only) Python 3.13 build with minimal risk while
installing or testing.  This installation layout is itself experimental
and is subject to change in future releases.

Known cautions and limitations:

   - The 'UNIX command-line tools' package, which is selected by
     default, will install links in ‘/usr/local/bin’ for ‘python3.13t’,
     the free-threaded interpreter, and ‘python3.13t-config’, a
     configuration utility which may be useful for package builders.
     Since ‘/usr/local/bin’ is typically included in your shell ‘PATH’,
     in most cases no changes to your ‘PATH’ environment variables
     should be needed to use ‘python3.13t’.

   - For this release, the 'Shell profile updater' package and the
     ‘Update Shell Profile.command’ in ‘/Applications/Python 3.13/’ do
     not support the free-threaded package.

   - The free-threaded build and the traditional build have separate
     search paths and separate ‘site-packages’ directories so, by
     default, if you need a package available in both builds, it may
     need to be installed in both.  The free-threaded package will
     install a separate instance of ‘pip’ for use with ‘python3.13t’.

        - To install a package using ‘pip’ without a ‘venv’:

               python3.13t -m pip install <package_name>

   - When working with multiple Python environments, it is usually
     safest and easiest to *note create and use virtual environments:
     1ea2.  This can avoid possible command name conflicts and confusion
     about which Python is in use:

          python3.13t -m venv <venv_name>

     then ‘activate’.

   - To run a free-threaded version of IDLE:

          python3.13t -m idlelib

   - The interpreters in both builds respond to the same *note PYTHON
     environment variables: 5f4. which may have unexpected results, for
     example, if you have ‘PYTHONPATH’ set in a shell profile.  If
     necessary, there are *note command line options: 1ed2. like ‘-E’ to
     ignore these environment variables.

   - The free-threaded build links to the third-party shared libraries,
     such as ‘OpenSSL’ and ‘Tk’, installed in the traditional framework.
     This means that both builds also share one set of trust
     certificates as installed by the ‘Install Certificates.command’
     script, thus it only needs to be run once.

   - If you cannot depend on the link in ‘/usr/local/bin’ pointing to
     the ‘python.org’ free-threaded ‘python3.13t’ (for example, if you
     want to install your own version there or some other distribution
     does), you can explicitly set your shell ‘PATH’ environment
     variable to include the ‘PythonT’ framework ‘bin’ directory:

          export PATH="/Library/Frameworks/PythonT.framework/Versions/3.13/bin":"$PATH"

     The traditional framework installation by default does something
     similar, except for ‘Python.framework’.  Be aware that having both
     framework ‘bin’ directories in ‘PATH’ can lead to confusion if
     there are duplicate names like ‘python3.13’ in both; which one is
     actually used depends on the order they appear in ‘PATH’.  The
     ‘which python3.x’ or ‘which python3.xt’ commands can show which
     path is being used.  Using virtual environments can help avoid such
     ambiguities.  Another option might be to create a shell ‘alias’ to
     the desired interpreter, like:

          alias py3.13="/Library/Frameworks/Python.framework/Versions/3.13/bin/python3.13"
          alias py3.13t="/Library/Frameworks/PythonT.framework/Versions/3.13/bin/python3.13t"

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/


File: python.info,  Node: Installing using the command line,  Next: Distributing Python Applications,  Prev: Installing Free-threaded Binaries<2>,  Up: Advanced Topics

3.5.5.2 Installing using the command line
.........................................

If you want to use automation to install the ‘python.org’ installer
package (rather than by using the familiar macOS ‘Installer’ GUI app),
the macOS command line ‘installer’ utility lets you select non-default
options, too.  If you are not familiar with ‘installer’, it can be
somewhat cryptic (see ‘man installer’ for more information).  As an
example, the following shell snippet shows one way to do it, using the
‘3.13.0b2’ release and selecting the free-threaded interpreter option:

     RELEASE="python-3.130b2-macos11.pkg"

     # download installer pkg
     curl -O https://www.python.org/ftp/python/3.13.0/${RELEASE}

     # create installer choicechanges to customize the install:
     #    enable the PythonTFramework-3.13 package
     #    while accepting the other defaults (install all other packages)
     cat > ./choicechanges.plist <<EOF
     <?xml version="1.0" encoding="UTF-8"?>
     <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
     <plist version="1.0">
     <array>
             <dict>
                     <key>attributeSetting</key>
                     <integer>1</integer>
                     <key>choiceAttribute</key>
                     <string>selected</string>
                     <key>choiceIdentifier</key>
                     <string>org.python.Python.PythonTFramework-3.13</string>
             </dict>
     </array>
     </plist>
     EOF

     sudo installer -pkg ./${RELEASE} -applyChoiceChangesXML ./choicechanges.plist -target /

You can then test that both installer builds are now available with
something like:

     $ # test that the free-threaded interpreter was installed if the Unix Command Tools package was enabled
     $ /usr/local/bin/python3.13t -VV
     Python 3.13.0b2 experimental free-threading build (v3.13.0b2:3a83b172af, Jun  5 2024, 12:57:31) [Clang 15.0.0 (clang-1500.3.9.4)]
     $ #    and the traditional interpreter
     $ /usr/local/bin/python3.13 -VV
     Python 3.13.0b2 (v3.13.0b2:3a83b172af, Jun  5 2024, 12:50:24) [Clang 15.0.0 (clang-1500.3.9.4)]
     $ # test that they are also available without the prefix if /usr/local/bin is on $PATH
     $ python3.13t -VV
     Python 3.13.0b2 experimental free-threading build (v3.13.0b2:3a83b172af, Jun  5 2024, 12:57:31) [Clang 15.0.0 (clang-1500.3.9.4)]
     $ python3.13 -VV
     Python 3.13.0b2 (v3.13.0b2:3a83b172af, Jun  5 2024, 12:50:24) [Clang 15.0.0 (clang-1500.3.9.4)]

     Note: Current ‘python.org’ installers only install to fixed
     locations like ‘/Library/Frameworks/’, ‘/Applications’, and
     ‘/usr/local/bin’.  You cannot use the ‘installer’ ‘-domain’ option
     to install to other locations.


File: python.info,  Node: Distributing Python Applications,  Next: App Store Compliance,  Prev: Installing using the command line,  Up: Advanced Topics

3.5.5.3 Distributing Python Applications
........................................

A range of tools exist for converting your Python code into a standalone
distributable application:

   * py2app(1): Supports creating macOS ‘.app’ bundles from a Python
     project.

   * Briefcase(2): Part of the BeeWare Project(3); a cross-platform
     packaging tool that supports creation of ‘.app’ bundles on macOS,
     as well as managing signing and notarization.

   * PyInstaller(4): A cross-platform packaging tool that creates a
     single file or folder as a distributable artifact.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/py2app/

   (2) https://briefcase.readthedocs.io

   (3) https://beeware.org

   (4) https://pyinstaller.org/


File: python.info,  Node: App Store Compliance,  Prev: Distributing Python Applications,  Up: Advanced Topics

3.5.5.4 App Store Compliance
............................

Apps submitted for distribution through the macOS App Store must pass
Apple’s app review process.  This process includes a set of automated
validation rules that inspect the submitted application bundle for
problematic code.

The Python standard library contains some code that is known to violate
these automated rules.  While these violations appear to be false
positives, Apple’s review rules cannot be challenged.  Therefore, it is
necessary to modify the Python standard library for an app to pass App
Store review.

The Python source tree contains a patch file(1) that will remove all
code that is known to cause issues with the App Store review process.
This patch is applied automatically when CPython is configured with the
*note -with-app-store-compliance: 16fc. option.

This patch is not normally required to use CPython on a Mac; nor is it
required if you are distributing an app 'outside' the macOS App Store.
It is 'only' required if you are using the macOS App Store as a
distribution channel.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Mac/Resources/app-store-compliance.patch


File: python.info,  Node: Other Resources,  Prev: Advanced Topics,  Up: Using Python on macOS

3.5.6 Other Resources
---------------------

The python.org Help page(1) has links to many useful resources.  The
Pythonmac-SIG mailing list(2) is another support resource specifically
for Python users and developers on the Mac.

   ---------- Footnotes ----------

   (1) https://www.python.org/about/help/

   (2) https://www.python.org/community/sigs/current/pythonmac-sig/


File: python.info,  Node: Using Python on Android,  Next: Using Python on iOS,  Prev: Using Python on macOS,  Up: Python Setup and Usage

3.6 Using Python on Android
===========================

Python on Android is unlike Python on desktop platforms.  On a desktop
platform, Python is generally installed as a system resource that can be
used by any user of that computer.  Users then interact with Python by
running a ‘python’ executable and entering commands at an interactive
prompt, or by running a Python script.

On Android, there is no concept of installing as a system resource.  The
only unit of software distribution is an “app”.  There is also no
console where you could run a ‘python’ executable, or interact with a
Python REPL.

As a result, the only way you can use Python on Android is in embedded
mode – that is, by writing a native Android application, embedding a
Python interpreter using ‘libpython’, and invoking Python code using the
*note Python embedding API: 1ffc.  The full Python interpreter, the
standard library, and all your Python code is then packaged into your
app for its own private use.

The Python standard library has some notable omissions and restrictions
on Android.  See the *note API availability guide: 1ffd. for details.

* Menu:

* Adding Python to an Android app::
* Building a Python package for Android::


File: python.info,  Node: Adding Python to an Android app,  Next: Building a Python package for Android,  Up: Using Python on Android

3.6.1 Adding Python to an Android app
-------------------------------------

Most app developers should use one of the following tools, which will
provide a much easier experience:

   * Briefcase(1), from the BeeWare project

   * Buildozer(2), from the Kivy project

   * Chaquopy(3)

   * pyqtdeploy(4)

   * Termux(5)

If you’re sure you want to do all of this manually, read on.  You can
use the testbed app(6) as a guide; each step below contains a link to
the relevant file.

   * Build Python by following the instructions in Android/README.md(7).
     This will create the directory ‘cross-build/HOST/prefix’.

   * Add code to your build.gradle(8) file to copy the following items
     into your project.  All except your own Python code can be copied
     from ‘prefix/lib’:

        * In your JNI libraries:

             * ‘libpython*.*.so’

             * ‘lib*_python.so’ (external libraries such as OpenSSL)

        * In your assets:

             * ‘python*.*’ (the Python standard library)

             * ‘python*.*/site-packages’ (your own Python code)

   * Add code to your app to extract the assets to the filesystem(9).

   * Add code to your app to start Python in embedded mode(10).  This
     will need to be C code called via JNI.

   ---------- Footnotes ----------

   (1) https://briefcase.readthedocs.io

   (2) https://buildozer.readthedocs.io

   (3) https://chaquo.com/chaquopy

   (4) https://www.riverbankcomputing.com/static/Docs/pyqtdeploy/

   (5) https://termux.dev/en/

   (6) https://github.com/python/cpython/tree/3.13/Android/testbed

   (7) https://github.com/python/cpython/tree/3.13/Android/README.md

   (8) 
https://github.com/python/cpython/tree/3.13/Android/testbed/app/build.gradle.kts

   (9) 
https://github.com/python/cpython/tree/3.13/Android/testbed/app/src/main/java/org/python/testbed/MainActivity.kt

   (10) 
https://github.com/python/cpython/tree/3.13/Android/testbed/app/src/main/c/main_activity.c


File: python.info,  Node: Building a Python package for Android,  Prev: Adding Python to an Android app,  Up: Using Python on Android

3.6.2 Building a Python package for Android
-------------------------------------------

Python packages can be built for Android as wheels and released on PyPI.
The recommended tool for doing this is cibuildwheel(1), which automates
all the details of setting up a cross-compilation environment, building
the wheel, and testing it on an emulator.

   ---------- Footnotes ----------

   (1) https://cibuildwheel.pypa.io/en/stable/platforms/#android


File: python.info,  Node: Using Python on iOS,  Next: Editors and IDEs,  Prev: Using Python on Android,  Up: Python Setup and Usage

3.7 Using Python on iOS
=======================


Authors: Russell Keith-Magee (2024-03)

Python on iOS is unlike Python on desktop platforms.  On a desktop
platform, Python is generally installed as a system resource that can be
used by any user of that computer.  Users then interact with Python by
running a ‘python’ executable and entering commands at an interactive
prompt, or by running a Python script.

On iOS, there is no concept of installing as a system resource.  The
only unit of software distribution is an “app”.  There is also no
console where you could run a ‘python’ executable, or interact with a
Python REPL.

As a result, the only way you can use Python on iOS is in embedded mode
- that is, by writing a native iOS application, and embedding a Python
interpreter using ‘libPython’, and invoking Python code using the *note
Python embedding API: 1ffc.  The full Python interpreter, the standard
library, and all your Python code is then packaged as a standalone
bundle that can be distributed via the iOS App Store.

If you’re looking to experiment for the first time with writing an iOS
app in Python, projects such as BeeWare(1) and Kivy(2) will provide a
much more approachable user experience.  These projects manage the
complexities associated with getting an iOS project running, so you only
need to deal with the Python code itself.

* Menu:

* Python at runtime on iOS::
* Installing Python on iOS::
* App Store Compliance: App Store Compliance<2>.

   ---------- Footnotes ----------

   (1) https://beeware.org

   (2) https://kivy.org


File: python.info,  Node: Python at runtime on iOS,  Next: Installing Python on iOS,  Up: Using Python on iOS

3.7.1 Python at runtime on iOS
------------------------------

* Menu:

* iOS version compatibility::
* Platform identification::
* Standard library availability::
* Binary extension modules::
* Compiler stub binaries::


File: python.info,  Node: iOS version compatibility,  Next: Platform identification,  Up: Python at runtime on iOS

3.7.1.1 iOS version compatibility
.................................

The minimum supported iOS version is specified at compile time, using
the *note -host: 1f79. option to ‘configure’.  By default, when compiled
for iOS, Python will be compiled with a minimum supported iOS version of
13.0.  To use a different minimum iOS version, provide the version
number as part of the ‘--host’ argument - for example,
‘--host=arm64-apple-ios15.4-simulator’ would compile an ARM64 simulator
build with a deployment target of 15.4.


File: python.info,  Node: Platform identification,  Next: Standard library availability,  Prev: iOS version compatibility,  Up: Python at runtime on iOS

3.7.1.2 Platform identification
...............................

When executing on iOS, ‘sys.platform’ will report as ‘ios’.  This value
will be returned on an iPhone or iPad, regardless of whether the app is
running on the simulator or a physical device.

Information about the specific runtime environment, including the iOS
version, device model, and whether the device is a simulator, can be
obtained using *note platform.ios_ver(): 2007.  *note platform.system():
2008. will report ‘iOS’ or ‘iPadOS’, depending on the device.

*note os.uname(): 115a. reports kernel-level details; it will report a
name of ‘Darwin’.


File: python.info,  Node: Standard library availability,  Next: Binary extension modules,  Prev: Platform identification,  Up: Python at runtime on iOS

3.7.1.3 Standard library availability
.....................................

The Python standard library has some notable omissions and restrictions
on iOS. See the *note API availability guide for iOS: 1ffd. for details.


File: python.info,  Node: Binary extension modules,  Next: Compiler stub binaries,  Prev: Standard library availability,  Up: Python at runtime on iOS

3.7.1.4 Binary extension modules
................................

One notable difference about iOS as a platform is that App Store
distribution imposes hard requirements on the packaging of an
application.  One of these requirements governs how binary extension
modules are distributed.

The iOS App Store requires that 'all' binary modules in an iOS app must
be dynamic libraries, contained in a framework with appropriate
metadata, stored in the ‘Frameworks’ folder of the packaged app.  There
can be only a single binary per framework, and there can be no
executable binary material outside the ‘Frameworks’ folder.

This conflicts with the usual Python approach for distributing binaries,
which allows a binary extension module to be loaded from any location on
‘sys.path’.  To ensure compliance with App Store policies, an iOS
project must post-process any Python packages, converting ‘.so’ binary
modules into individual standalone frameworks with appropriate metadata
and signing.  For details on how to perform this post-processing, see
the guide for *note adding Python to your project: 200b.

To help Python discover binaries in their new location, the original
‘.so’ file on ‘sys.path’ is replaced with a ‘.fwork’ file.  This file is
a text file containing the location of the framework binary, relative to
the app bundle.  To allow the framework to resolve back to the original
location, the framework must contain a ‘.origin’ file that contains the
location of the ‘.fwork’ file, relative to the app bundle.

For example, consider the case of an import ‘from foo.bar import _whiz’,
where ‘_whiz’ is implemented with the binary module
‘sources/foo/bar/_whiz.abi3.so’, with ‘sources’ being the location
registered on ‘sys.path’, relative to the application bundle.  This
module 'must' be distributed as
‘Frameworks/foo.bar._whiz.framework/foo.bar._whiz’ (creating the
framework name from the full import path of the module), with an
‘Info.plist’ file in the ‘.framework’ directory identifying the binary
as a framework.  The ‘foo.bar._whiz’ module would be represented in the
original location with a ‘sources/foo/bar/_whiz.abi3.fwork’ marker file,
containing the path ‘Frameworks/foo.bar._whiz/foo.bar._whiz’.  The
framework would also contain
‘Frameworks/foo.bar._whiz.framework/foo.bar._whiz.origin’, containing
the path to the ‘.fwork’ file.

When running on iOS, the Python interpreter will install an *note
AppleFrameworkLoader: 200c. that is able to read and import ‘.fwork’
files.  Once imported, the ‘__file__’ attribute of the binary module
will report as the location of the ‘.fwork’ file.  However, the *note
ModuleSpec: 200d. for the loaded module will report the ‘origin’ as the
location of the binary in the framework folder.


File: python.info,  Node: Compiler stub binaries,  Prev: Binary extension modules,  Up: Python at runtime on iOS

3.7.1.5 Compiler stub binaries
..............................

Xcode doesn’t expose explicit compilers for iOS; instead, it uses an
‘xcrun’ script that resolves to a full compiler path (e.g., ‘xcrun --sdk
iphoneos clang’ to get the ‘clang’ for an iPhone device).  However,
using this script poses two problems:

   * The output of ‘xcrun’ includes paths that are machine specific,
     resulting in a sysconfig module that cannot be shared between
     users; and

   * It results in ‘CC’/‘CPP’/‘LD’/‘AR’ definitions that include spaces.
     There is a lot of C ecosystem tooling that assumes that you can
     split a command line at the first space to get the path to the
     compiler executable; this isn’t the case when using ‘xcrun’.

To avoid these problems, Python provided stubs for these tools.  These
stubs are shell script wrappers around the underingly ‘xcrun’ tools,
distributed in a ‘bin’ folder distributed alongside the compiled iOS
framework.  These scripts are relocatable, and will always resolve to
the appropriate local system paths.  By including these scripts in the
bin folder that accompanies a framework, the contents of the ‘sysconfig’
module becomes useful for end-users to compile their own modules.  When
compiling third-party Python modules for iOS, you should ensure these
stub binaries are on your path.


File: python.info,  Node: Installing Python on iOS,  Next: App Store Compliance<2>,  Prev: Python at runtime on iOS,  Up: Using Python on iOS

3.7.2 Installing Python on iOS
------------------------------

* Menu:

* Tools for building iOS apps::
* Adding Python to an iOS project::
* Testing a Python package::


File: python.info,  Node: Tools for building iOS apps,  Next: Adding Python to an iOS project,  Up: Installing Python on iOS

3.7.2.1 Tools for building iOS apps
...................................

Building for iOS requires the use of Apple’s Xcode tooling.  It is
strongly recommended that you use the most recent stable release of
Xcode.  This will require the use of the most (or second-most) recently
released macOS version, as Apple does not maintain Xcode for older macOS
versions.  The Xcode Command Line Tools are not sufficient for iOS
development; you need a 'full' Xcode install.

If you want to run your code on the iOS simulator, you’ll also need to
install an iOS Simulator Platform.  You should be prompted to select an
iOS Simulator Platform when you first run Xcode.  Alternatively, you can
add an iOS Simulator Platform by selecting from the Platforms tab of the
Xcode Settings panel.


File: python.info,  Node: Adding Python to an iOS project,  Next: Testing a Python package,  Prev: Tools for building iOS apps,  Up: Installing Python on iOS

3.7.2.2 Adding Python to an iOS project
.......................................

Python can be added to any iOS project, using either Swift or Objective
C. The following examples will use Objective C; if you are using Swift,
you may find a library like PythonKit(1) to be helpful.

To add Python to an iOS Xcode project:

  1. Build or obtain a Python ‘XCFramework’.  See the instructions in
     iOS/README.rst(2) (in the CPython source distribution) for details
     on how to build a Python ‘XCFramework’.  At a minimum, you will
     need a build that supports ‘arm64-apple-ios’, plus one of either
     ‘arm64-apple-ios-simulator’ or ‘x86_64-apple-ios-simulator’.

  2. Drag the ‘XCframework’ into your iOS project.  In the following
     instructions, we’ll assume you’ve dropped the ‘XCframework’ into
     the root of your project; however, you can use any other location
     that you want by adjusting paths as needed.

  3. Drag the ‘iOS/Resources/dylib-Info-template.plist’ file into your
     project, and ensure it is associated with the app target.

  4. Add your application code as a folder in your Xcode project.  In
     the following instructions, we’ll assume that your user code is in
     a folder named ‘app’ in the root of your project; you can use any
     other location by adjusting paths as needed.  Ensure that this
     folder is associated with your app target.

  5. Select the app target by selecting the root node of your Xcode
     project, then the target name in the sidebar that appears.

  6. In the “General” settings, under “Frameworks, Libraries and
     Embedded Content”, add ‘Python.xcframework’, with “Embed & Sign”
     selected.

  7. In the “Build Settings” tab, modify the following:

        - Build Options

             * User Script Sandboxing: No

             * Enable Testability: Yes

        - Search Paths

             * Framework Search Paths: ‘$(PROJECT_DIR)’

             * Header Search Paths:
               ‘"$(BUILT_PRODUCTS_DIR)/Python.framework/Headers"’

        - Apple Clang - Warnings - All languages

             * Quoted Include In Framework Header: No

  8. Add a build step that copies the Python standard library into your
     app.  In the “Build Phases” tab, add a new “Run Script” build step
     'before' the “Embed Frameworks” step, but 'after' the “Copy Bundle
     Resources” step.  Name the step “Install Target Specific Python
     Standard Library”, disable the “Based on dependency analysis”
     checkbox, and set the script content to:

          set -e

          mkdir -p "$CODESIGNING_FOLDER_PATH/python/lib"
          if [ "$EFFECTIVE_PLATFORM_NAME" = "-iphonesimulator" ]; then
              echo "Installing Python modules for iOS Simulator"
              rsync -au --delete "$PROJECT_DIR/Python.xcframework/ios-arm64_x86_64-simulator/lib/" "$CODESIGNING_FOLDER_PATH/python/lib/"
          else
              echo "Installing Python modules for iOS Device"
              rsync -au --delete "$PROJECT_DIR/Python.xcframework/ios-arm64/lib/" "$CODESIGNING_FOLDER_PATH/python/lib/"
          fi

     Note that the name of the simulator “slice” in the XCframework may
     be different, depending the CPU architectures your ‘XCFramework’
     supports.

  9. Add a second build step that processes the binary extension modules
     in the standard library into “Framework” format.  Add a “Run
     Script” build step 'directly after' the one you added in step 8,
     named “Prepare Python Binary Modules”.  It should also have “Based
     on dependency analysis” unchecked, with the following script
     content:

          set -e

          install_dylib () {
              INSTALL_BASE=$1
              FULL_EXT=$2

              # The name of the extension file
              EXT=$(basename "$FULL_EXT")
              # The location of the extension file, relative to the bundle
              RELATIVE_EXT=${FULL_EXT#$CODESIGNING_FOLDER_PATH/}
              # The path to the extension file, relative to the install base
              PYTHON_EXT=${RELATIVE_EXT/$INSTALL_BASE/}
              # The full dotted name of the extension module, constructed from the file path.
              FULL_MODULE_NAME=$(echo $PYTHON_EXT | cut -d "." -f 1 | tr "/" ".");
              # A bundle identifier; not actually used, but required by Xcode framework packaging
              FRAMEWORK_BUNDLE_ID=$(echo $PRODUCT_BUNDLE_IDENTIFIER.$FULL_MODULE_NAME | tr "_" "-")
              # The name of the framework folder.
              FRAMEWORK_FOLDER="Frameworks/$FULL_MODULE_NAME.framework"

              # If the framework folder doesn't exist, create it.
              if [ ! -d "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER" ]; then
                  echo "Creating framework for $RELATIVE_EXT"
                  mkdir -p "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER"
                  cp "$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
                  plutil -replace CFBundleExecutable -string "$FULL_MODULE_NAME" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
                  plutil -replace CFBundleIdentifier -string "$FRAMEWORK_BUNDLE_ID" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist"
              fi

              echo "Installing binary for $FRAMEWORK_FOLDER/$FULL_MODULE_NAME"
              mv "$FULL_EXT" "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME"
              # Create a placeholder .fwork file where the .so was
              echo "$FRAMEWORK_FOLDER/$FULL_MODULE_NAME" > ${FULL_EXT%.so}.fwork
              # Create a back reference to the .so file location in the framework
              echo "${RELATIVE_EXT%.so}.fwork" > "$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME.origin"
           }

           PYTHON_VER=$(ls -1 "$CODESIGNING_FOLDER_PATH/python/lib")
           echo "Install Python $PYTHON_VER standard library extension modules..."
           find "$CODESIGNING_FOLDER_PATH/python/lib/$PYTHON_VER/lib-dynload" -name "*.so" | while read FULL_EXT; do
              install_dylib python/lib/$PYTHON_VER/lib-dynload/ "$FULL_EXT"
           done

           # Clean up dylib template
           rm -f "$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist"

           echo "Signing frameworks as $EXPANDED_CODE_SIGN_IDENTITY_NAME ($EXPANDED_CODE_SIGN_IDENTITY)..."
           find "$CODESIGNING_FOLDER_PATH/Frameworks" -name "*.framework" -exec /usr/bin/codesign --force --sign "$EXPANDED_CODE_SIGN_IDENTITY" ${OTHER_CODE_SIGN_FLAGS:-} -o runtime --timestamp=none --preserve-metadata=identifier,entitlements,flags --generate-entitlement-der "{}" \;

  10. Add Objective C code to initialize and use a Python interpreter in
     embedded mode.  You should ensure that:

        * UTF-8 mode (*note PyPreConfig.utf8_mode: 3ed.) is 'enabled';

        * Buffered stdio (*note PyConfig.buffered_stdio: 3e2.) is
          'disabled';

        * Writing bytecode (*note PyConfig.write_bytecode: 3de.) is
          'disabled';

        * Signal handlers (*note PyConfig.install_signal_handlers: 8c6.)
          are 'enabled';

        * *note PYTHONHOME: 3bf. for the interpreter is configured to
          point at the ‘python’ subfolder of your app’s bundle; and

        * The *note PYTHONPATH: 1058. for the interpreter includes:

             - the ‘python/lib/python3.X’ subfolder of your app’s
               bundle,

             - the ‘python/lib/python3.X/lib-dynload’ subfolder of your
               app’s bundle, and

             - the ‘app’ subfolder of your app’s bundle

     Your app’s bundle location can be determined using ‘[[NSBundle
     mainBundle] resourcePath]’.

Steps 8, 9 and 10 of these instructions assume that you have a single
folder of pure Python application code, named ‘app’.  If you have
third-party binary modules in your app, some additional steps will be
required:

   * You need to ensure that any folders containing third-party binaries
     are either associated with the app target, or copied in as part of
     step 8.  Step 8 should also purge any binaries that are not
     appropriate for the platform a specific build is targeting (i.e.,
     delete any device binaries if you’re building an app targeting the
     simulator).

   * Any folders that contain third-party binaries must be processed
     into framework form by step 9.  The invocation of ‘install_dylib’
     that processes the ‘lib-dynload’ folder can be copied and adapted
     for this purpose.

   * If you’re using a separate folder for third-party packages, ensure
     that folder is included as part of the *note PYTHONPATH: 1058.
     configuration in step 10.

   * If any of the folders that contain third-party packages will
     contain ‘.pth’ files, you should add that folder as a 'site
     directory' (using *note site.addsitedir(): 2012.), rather than
     adding to *note PYTHONPATH: 1058. or *note sys.path: 3b7. directly.

   ---------- Footnotes ----------

   (1) https://github.com/pvieito/PythonKit

   (2) https://github.com/python/cpython/tree/3.13/iOS/README.rst


File: python.info,  Node: Testing a Python package,  Prev: Adding Python to an iOS project,  Up: Installing Python on iOS

3.7.2.3 Testing a Python package
................................

The CPython source tree contains a testbed project(1) that is used to
run the CPython test suite on the iOS simulator.  This testbed can also
be used as a testbed project for running your Python library’s test
suite on iOS.

After building or obtaining an iOS XCFramework (See iOS/README.rst(2)
for details), create a clone of the Python iOS testbed project by
running:

     $ python iOS/testbed clone --framework <path/to/Python.xcframework> --app <path/to/module1> --app <path/to/module2> app-testbed

You will need to modify the ‘iOS/testbed’ reference to point to that
directory in the CPython source tree; any folders specified with the
‘--app’ flag will be copied into the cloned testbed project.  The
resulting testbed will be created in the ‘app-testbed’ folder.  In this
example, the ‘module1’ and ‘module2’ would be importable modules at
runtime.  If your project has additional dependencies, they can be
installed into the ‘app-testbed/iOSTestbed/app_packages’ folder (using
‘pip install --target app-testbed/iOSTestbed/app_packages’ or similar).

You can then use the ‘app-testbed’ folder to run the test suite for your
app, For example, if ‘module1.tests’ was the entry point to your test
suite, you could run:

     $ python app-testbed run -- module1.tests

This is the equivalent of running ‘python -m module1.tests’ on a desktop
Python build.  Any arguments after the ‘--’ will be passed to the
testbed as if they were arguments to ‘python -m’ on a desktop machine.

You can also open the testbed project in Xcode by running:

     $ open app-testbed/iOSTestbed.xcodeproj

This will allow you to use the full Xcode suite of tools for debugging.

The arguments used to run the test suite are defined as part of the test
plan.  To modify the test plan, select the test plan node of the project
tree (it should be the first child of the root node), and select the
“Configurations” tab.  Modify the “Arguments Passed On Launch” value to
change the testing arguments.

The test plan also disables parallel testing, and specifies the use of
the ‘iOSTestbed.lldbinit’ file for providing configuration of the
debugger.  The default debugger configuration disables automatic
breakpoints on the ‘SIGINT’, ‘SIGUSR1’, ‘SIGUSR2’, and ‘SIGXFSZ’
signals.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/iOS/testbed

   (2) https://github.com/python/cpython/tree/3.13/iOS/README.rst


File: python.info,  Node: App Store Compliance<2>,  Prev: Installing Python on iOS,  Up: Using Python on iOS

3.7.3 App Store Compliance
--------------------------

The only mechanism for distributing apps to third-party iOS devices is
to submit the app to the iOS App Store; apps submitted for distribution
must pass Apple’s app review process.  This process includes a set of
automated validation rules that inspect the submitted application bundle
for problematic code.

The Python standard library contains some code that is known to violate
these automated rules.  While these violations appear to be false
positives, Apple’s review rules cannot be challenged; so, it is
necessary to modify the Python standard library for an app to pass App
Store review.

The Python source tree contains a patch file(1) that will remove all
code that is known to cause issues with the App Store review process.
This patch is applied automatically when building for iOS.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Mac/Resources/app-store-compliance.patch


File: python.info,  Node: Editors and IDEs,  Prev: Using Python on iOS,  Up: Python Setup and Usage

3.8 Editors and IDEs
====================

There are a number of IDEs that support Python programming language.
Many editors and IDEs provide syntax highlighting, debugging tools, and
PEP 8(1) checks.

* Menu:

* IDLE — Python editor and shell::
* Other Editors and IDEs::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: IDLE — Python editor and shell,  Next: Other Editors and IDEs,  Up: Editors and IDEs

3.8.1 IDLE — Python editor and shell
------------------------------------

IDLE is Python’s Integrated Development and Learning Environment and is
generally bundled with Python installs.  If you are on Linux and do not
have IDLE installed see *note Installing IDLE on Linux: 1f01.  For more
information see the *note IDLE docs: 1050.


File: python.info,  Node: Other Editors and IDEs,  Prev: IDLE — Python editor and shell,  Up: Editors and IDEs

3.8.2 Other Editors and IDEs
----------------------------

Python’s community wiki has information submitted by the community on
Editors and IDEs.  Please go to Python Editors(1) and Integrated
Development Environments(2) for a comprehensive list.

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/PythonEditors

   (2) https://wiki.python.org/moin/IntegratedDevelopmentEnvironments


File: python.info,  Node: The Python Language Reference,  Next: The Python Standard Library,  Prev: Python Setup and Usage,  Up: Top

4 The Python Language Reference
*******************************

This reference manual describes the syntax and “core semantics” of the
language.  It is terse, but attempts to be exact and complete.  The
semantics of non-essential built-in object types and of the built-in
functions and modules are described in *note The Python Standard
Library: 144.  For an informal introduction to the language, see *note
The Python Tutorial: 1d6d.  For C or C++ programmers, two additional
manuals exist: *note Extending and Embedding the Python Interpreter:
1d6e. describes the high-level picture of how to write a Python
extension module, and the *note Python/C API Reference Manual: 1d6f.
describes the interfaces available to C/C++ programmers in detail.

* Menu:

* Introduction: Introduction<5>.
* Lexical analysis::
* Data model::
* Execution model::
* The import system::
* Expressions::
* Simple statements::
* Compound statements::
* Top-level components::
* Full Grammar specification::


File: python.info,  Node: Introduction<5>,  Next: Lexical analysis,  Up: The Python Language Reference

4.1 Introduction
================

This reference manual describes the Python programming language.  It is
not intended as a tutorial.

While I am trying to be as precise as possible, I chose to use English
rather than formal specifications for everything except syntax and
lexical analysis.  This should make the document more understandable to
the average reader, but will leave room for ambiguities.  Consequently,
if you were coming from Mars and tried to re-implement Python from this
document alone, you might have to guess things and in fact you would
probably end up implementing quite a different language.  On the other
hand, if you are using Python and wonder what the precise rules about a
particular area of the language are, you should definitely be able to
find them here.  If you would like to see a more formal definition of
the language, maybe you could volunteer your time — or invent a cloning
machine :-).

It is dangerous to add too many implementation details to a language
reference document — the implementation may change, and other
implementations of the same language may work differently.  On the other
hand, CPython is the one Python implementation in widespread use
(although alternate implementations continue to gain support), and its
particular quirks are sometimes worth being mentioned, especially where
the implementation imposes additional limitations.  Therefore, you’ll
find short “implementation notes” sprinkled throughout the text.

Every Python implementation comes with a number of built-in and standard
modules.  These are documented in *note The Python Standard Library:
144.  A few built-in modules are mentioned when they interact in a
significant way with the language definition.

* Menu:

* Alternate Implementations::
* Notation::


File: python.info,  Node: Alternate Implementations,  Next: Notation,  Up: Introduction<5>

4.1.1 Alternate Implementations
-------------------------------

Though there is one Python implementation which is by far the most
popular, there are some alternate implementations which are of
particular interest to different audiences.

Known implementations include:

CPython

     This is the original and most-maintained implementation of Python,
     written in C. New language features generally appear here first.

Jython

     Python implemented in Java.  This implementation can be used as a
     scripting language for Java applications, or can be used to create
     applications using the Java class libraries.  It is also often used
     to create tests for Java libraries.  More information can be found
     at the Jython website(1).

Python for .NET

     This implementation actually uses the CPython implementation, but
     is a managed .NET application and makes .NET libraries available.
     It was created by Brian Lloyd.  For more information, see the
     Python for .NET home page(2).

IronPython

     An alternate Python for .NET. Unlike Python.NET, this is a complete
     Python implementation that generates IL, and compiles Python code
     directly to .NET assemblies.  It was created by Jim Hugunin, the
     original creator of Jython.  For more information, see the
     IronPython website(3).

PyPy

     An implementation of Python written completely in Python.  It
     supports several advanced features not found in other
     implementations like stackless support and a Just in Time compiler.
     One of the goals of the project is to encourage experimentation
     with the language itself by making it easier to modify the
     interpreter (since it is written in Python).  Additional
     information is available on the PyPy project's home page(4).

Each of these implementations varies in some way from the language as
documented in this manual, or introduces specific information beyond
what’s covered in the standard Python documentation.  Please refer to
the implementation-specific documentation to determine what else you
need to know about the specific implementation you’re using.

   ---------- Footnotes ----------

   (1) https://www.jython.org/

   (2) https://pythonnet.github.io/

   (3) https://ironpython.net/

   (4) https://pypy.org/


File: python.info,  Node: Notation,  Prev: Alternate Implementations,  Up: Introduction<5>

4.1.2 Notation
--------------

The descriptions of lexical analysis and syntax use a modified
Backus–Naur form (BNF)(1) grammar notation.  This uses the following
style of definition:

     name      ::= *note lc_letter: 2024. (*note lc_letter: 2024. | "_")*
     lc_letter ::= "a"..."z"

The first line says that a ‘name’ is an ‘lc_letter’ followed by a
sequence of zero or more ‘lc_letter’s and underscores.  An ‘lc_letter’
in turn is any of the single characters ‘'a'’ through ‘'z'’.  (This rule
is actually adhered to for the names defined in lexical and grammar
rules in this document.)

Each rule begins with a name (which is the name defined by the rule) and
‘::=’.  A vertical bar (‘|’) is used to separate alternatives; it is the
least binding operator in this notation.  A star (‘*’) means zero or
more repetitions of the preceding item; likewise, a plus (‘+’) means one
or more repetitions, and a phrase enclosed in square brackets (‘[ ]’)
means zero or one occurrences (in other words, the enclosed phrase is
optional).  The ‘*’ and ‘+’ operators bind as tightly as possible;
parentheses are used for grouping.  Literal strings are enclosed in
quotes.  White space is only meaningful to separate tokens.  Rules are
normally contained on a single line; rules with many alternatives may be
formatted alternatively with each line after the first beginning with a
vertical bar.

In lexical definitions (as the example above), two more conventions are
used: Two literal characters separated by three dots mean a choice of
any single character in the given (inclusive) range of ASCII characters.
A phrase between angular brackets (‘<...>’) gives an informal
description of the symbol defined; e.g., this could be used to describe
the notion of ‘control character’ if needed.

Even though the notation used is almost the same, there is a big
difference between the meaning of lexical and syntactic definitions: a
lexical definition operates on the individual characters of the input
source, while a syntax definition operates on the stream of tokens
generated by the lexical analysis.  All uses of BNF in the next chapter
(“Lexical Analysis”) are lexical definitions; uses in subsequent
chapters are syntactic definitions.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form


File: python.info,  Node: Lexical analysis,  Next: Data model,  Prev: Introduction<5>,  Up: The Python Language Reference

4.2 Lexical analysis
====================

A Python program is read by a 'parser'.  Input to the parser is a stream
of *note tokens: 2029, generated by the 'lexical analyzer' (also known
as the 'tokenizer').  This chapter describes how the lexical analyzer
breaks a file into tokens.

Python reads program text as Unicode code points; the encoding of a
source file can be given by an encoding declaration and defaults to
UTF-8, see PEP 3120(1) for details.  If the source file cannot be
decoded, a *note SyntaxError: 18d. is raised.

* Menu:

* Line structure::
* Other tokens::
* Identifiers and keywords::
* Literals::
* Operators::
* Delimiters::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3120/


File: python.info,  Node: Line structure,  Next: Other tokens,  Up: Lexical analysis

4.2.1 Line structure
--------------------

A Python program is divided into a number of 'logical lines'.

* Menu:

* Logical lines::
* Physical lines::
* Comments::
* Encoding declarations::
* Explicit line joining::
* Implicit line joining::
* Blank lines::
* Indentation::
* Whitespace between tokens::


File: python.info,  Node: Logical lines,  Next: Physical lines,  Up: Line structure

4.2.1.1 Logical lines
.....................

The end of a logical line is represented by the token NEWLINE.
Statements cannot cross logical line boundaries except where NEWLINE is
allowed by the syntax (e.g., between statements in compound statements).
A logical line is constructed from one or more 'physical lines' by
following the explicit or implicit 'line joining' rules.


File: python.info,  Node: Physical lines,  Next: Comments,  Prev: Logical lines,  Up: Line structure

4.2.1.2 Physical lines
......................

A physical line is a sequence of characters terminated by an end-of-line
sequence.  In source files and strings, any of the standard platform
line termination sequences can be used - the Unix form using ASCII LF
(linefeed), the Windows form using the ASCII sequence CR LF (return
followed by linefeed), or the old Macintosh form using the ASCII CR
(return) character.  All of these forms can be used equally, regardless
of platform.  The end of input also serves as an implicit terminator for
the final physical line.

When embedding Python, source code strings should be passed to Python
APIs using the standard C conventions for newline characters (the ‘\n’
character, representing ASCII LF, is the line terminator).


File: python.info,  Node: Comments,  Next: Encoding declarations,  Prev: Physical lines,  Up: Line structure

4.2.1.3 Comments
................

A comment starts with a hash character (‘#’) that is not part of a
string literal, and ends at the end of the physical line.  A comment
signifies the end of the logical line unless the implicit line joining
rules are invoked.  Comments are ignored by the syntax.


File: python.info,  Node: Encoding declarations,  Next: Explicit line joining,  Prev: Comments,  Up: Line structure

4.2.1.4 Encoding declarations
.............................

If a comment in the first or second line of the Python script matches
the regular expression ‘coding[=:]\s*([-\w.]+)’, this comment is
processed as an encoding declaration; the first group of this expression
names the encoding of the source code file.  The encoding declaration
must appear on a line of its own.  If it is the second line, the first
line must also be a comment-only line.  The recommended forms of an
encoding expression are

     # -*- coding: <encoding-name> -*-

which is recognized also by GNU Emacs, and

     # vim:fileencoding=<encoding-name>

which is recognized by Bram Moolenaar’s VIM.

If no encoding declaration is found, the default encoding is UTF-8.  If
the implicit or explicit encoding of a file is UTF-8, an initial UTF-8
byte-order mark (‘b'\xef\xbb\xbf'’) is ignored rather than being a
syntax error.

If an encoding is declared, the encoding name must be recognized by
Python (see *note Standard Encodings: de7.).  The encoding is used for
all lexical analysis, including string literals, comments and
identifiers.


File: python.info,  Node: Explicit line joining,  Next: Implicit line joining,  Prev: Encoding declarations,  Up: Line structure

4.2.1.5 Explicit line joining
.............................

Two or more physical lines may be joined into logical lines using
backslash characters (‘\’), as follows: when a physical line ends in a
backslash that is not part of a string literal or comment, it is joined
with the following forming a single logical line, deleting the backslash
and the following end-of-line character.  For example:

     if 1900 < year < 2100 and 1 <= month <= 12 \
        and 1 <= day <= 31 and 0 <= hour < 24 \
        and 0 <= minute < 60 and 0 <= second < 60:   # Looks like a valid date
             return 1

A line ending in a backslash cannot carry a comment.  A backslash does
not continue a comment.  A backslash does not continue a token except
for string literals (i.e., tokens other than string literals cannot be
split across physical lines using a backslash).  A backslash is illegal
elsewhere on a line outside a string literal.


File: python.info,  Node: Implicit line joining,  Next: Blank lines,  Prev: Explicit line joining,  Up: Line structure

4.2.1.6 Implicit line joining
.............................

Expressions in parentheses, square brackets or curly braces can be split
over more than one physical line without using backslashes.  For
example:

     month_names = ['Januari', 'Februari', 'Maart',      # These are the
                    'April',   'Mei',      'Juni',       # Dutch names
                    'Juli',    'Augustus', 'September',  # for the months
                    'Oktober', 'November', 'December']   # of the year

Implicitly continued lines can carry comments.  The indentation of the
continuation lines is not important.  Blank continuation lines are
allowed.  There is no NEWLINE token between implicit continuation lines.
Implicitly continued lines can also occur within triple-quoted strings
(see below); in that case they cannot carry comments.


File: python.info,  Node: Blank lines,  Next: Indentation,  Prev: Implicit line joining,  Up: Line structure

4.2.1.7 Blank lines
...................

A logical line that contains only spaces, tabs, formfeeds and possibly a
comment, is ignored (i.e., no NEWLINE token is generated).  During
interactive input of statements, handling of a blank line may differ
depending on the implementation of the read-eval-print loop.  In the
standard interactive interpreter, an entirely blank logical line (i.e.
one containing not even whitespace or a comment) terminates a multi-line
statement.


File: python.info,  Node: Indentation,  Next: Whitespace between tokens,  Prev: Blank lines,  Up: Line structure

4.2.1.8 Indentation
...................

Leading whitespace (spaces and tabs) at the beginning of a logical line
is used to compute the indentation level of the line, which in turn is
used to determine the grouping of statements.

Tabs are replaced (from left to right) by one to eight spaces such that
the total number of characters up to and including the replacement is a
multiple of eight (this is intended to be the same rule as used by
Unix).  The total number of spaces preceding the first non-blank
character then determines the line’s indentation.  Indentation cannot be
split over multiple physical lines using backslashes; the whitespace up
to the first backslash determines the indentation.

Indentation is rejected as inconsistent if a source file mixes tabs and
spaces in a way that makes the meaning dependent on the worth of a tab
in spaces; a *note TabError: 546. is raised in that case.

'Cross-platform compatibility note:' because of the nature of text
editors on non-UNIX platforms, it is unwise to use a mixture of spaces
and tabs for the indentation in a single source file.  It should also be
noted that different platforms may explicitly limit the maximum
indentation level.

A formfeed character may be present at the start of the line; it will be
ignored for the indentation calculations above.  Formfeed characters
occurring elsewhere in the leading whitespace have an undefined effect
(for instance, they may reset the space count to zero).

The indentation levels of consecutive lines are used to generate INDENT
and DEDENT tokens, using a stack, as follows.

Before the first line of the file is read, a single zero is pushed on
the stack; this will never be popped off again.  The numbers pushed on
the stack will always be strictly increasing from bottom to top.  At the
beginning of each logical line, the line’s indentation level is compared
to the top of the stack.  If it is equal, nothing happens.  If it is
larger, it is pushed on the stack, and one INDENT token is generated.
If it is smaller, it 'must' be one of the numbers occurring on the
stack; all numbers on the stack that are larger are popped off, and for
each number popped off a DEDENT token is generated.  At the end of the
file, a DEDENT token is generated for each number remaining on the stack
that is larger than zero.

Here is an example of a correctly (though confusingly) indented piece of
Python code:

     def perm(l):
             # Compute the list of all permutations of l
         if len(l) <= 1:
                       return [l]
         r = []
         for i in range(len(l)):
                  s = l[:i] + l[i+1:]
                  p = perm(s)
                  for x in p:
                   r.append(l[i:i+1] + x)
         return r

The following example shows various indentation errors:

      def perm(l):                       # error: first line indented
     for i in range(len(l)):             # error: not indented
         s = l[:i] + l[i+1:]
             p = perm(l[:i] + l[i+1:])   # error: unexpected indent
             for x in p:
                     r.append(l[i:i+1] + x)
                 return r                # error: inconsistent dedent

(Actually, the first three errors are detected by the parser; only the
last error is found by the lexical analyzer — the indentation of ‘return
r’ does not match a level popped off the stack.)


File: python.info,  Node: Whitespace between tokens,  Prev: Indentation,  Up: Line structure

4.2.1.9 Whitespace between tokens
.................................

Except at the beginning of a logical line or in string literals, the
whitespace characters space, tab and formfeed can be used
interchangeably to separate tokens.  Whitespace is needed between two
tokens only if their concatenation could otherwise be interpreted as a
different token (e.g., ab is one token, but a b is two tokens).


File: python.info,  Node: Other tokens,  Next: Identifiers and keywords,  Prev: Line structure,  Up: Lexical analysis

4.2.2 Other tokens
------------------

Besides NEWLINE, INDENT and DEDENT, the following categories of tokens
exist: 'identifiers', 'keywords', 'literals', 'operators', and
'delimiters'.  Whitespace characters (other than line terminators,
discussed earlier) are not tokens, but serve to delimit tokens.  Where
ambiguity exists, a token comprises the longest possible string that
forms a legal token, when read from left to right.


File: python.info,  Node: Identifiers and keywords,  Next: Literals,  Prev: Other tokens,  Up: Lexical analysis

4.2.3 Identifiers and keywords
------------------------------

Identifiers (also referred to as 'names') are described by the following
lexical definitions.

The syntax of identifiers in Python is based on the Unicode standard
annex UAX-31, with elaboration and changes as defined below; see also
PEP 3131(1) for further details.

Within the ASCII range (U+0001..U+007F), the valid characters for
identifiers include the uppercase and lowercase letters ‘A’ through ‘Z’,
the underscore ‘_’ and, except for the first character, the digits ‘0’
through ‘9’.  Python 3.0 introduced additional characters from outside
the ASCII range (see PEP 3131(2)).  For these characters, the
classification uses the version of the Unicode Character Database as
included in the *note unicodedata: 105. module.

Identifiers are unlimited in length.  Case is significant.

     identifier   ::= *note xid_start: 2043. *note xid_continue: 2044.*
     id_start     ::= <all characters in general categories Lu, Ll, Lt, Lm, Lo, Nl, the underscore, and characters with the Other_ID_Start property>
     id_continue  ::= <all characters in *note id_start: 2045, plus characters in the categories Mn, Mc, Nd, Pc and others with the Other_ID_Continue property>
     xid_start    ::= <all characters in *note id_start: 2045. whose NFKC normalization is in "id_start xid_continue*">
     xid_continue ::= <all characters in *note id_continue: 2046. whose NFKC normalization is in "id_continue*">

The Unicode category codes mentioned above stand for:

   * 'Lu' - uppercase letters

   * 'Ll' - lowercase letters

   * 'Lt' - titlecase letters

   * 'Lm' - modifier letters

   * 'Lo' - other letters

   * 'Nl' - letter numbers

   * 'Mn' - nonspacing marks

   * 'Mc' - spacing combining marks

   * 'Nd' - decimal numbers

   * 'Pc' - connector punctuations

   * 'Other_ID_Start' - explicit list of characters in PropList.txt(3)
     to support backwards compatibility

   * 'Other_ID_Continue' - likewise

All identifiers are converted into the normal form NFKC while parsing;
comparison of identifiers is based on NFKC.

A non-normative HTML file listing all valid identifier characters for
Unicode 15.1.0 can be found at
‘https://www.unicode.org/Public/15.1.0/ucd/DerivedCoreProperties.txt’

* Menu:

* Keywords::
* Soft Keywords::
* Reserved classes of identifiers::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3131/

   (2) https://peps.python.org/pep-3131/

   (3) https://www.unicode.org/Public/15.1.0/ucd/PropList.txt


File: python.info,  Node: Keywords,  Next: Soft Keywords,  Up: Identifiers and keywords

4.2.3.1 Keywords
................

The following identifiers are used as reserved words, or 'keywords' of
the language, and cannot be used as ordinary identifiers.  They must be
spelled exactly as written here:

     False      await      else       import     pass
     None       break      except     in         raise
     True       class      finally    is         return
     and        continue   for        lambda     try
     as         def        from       nonlocal   while
     assert     del        global     not        with
     async      elif       if         or         yield


File: python.info,  Node: Soft Keywords,  Next: Reserved classes of identifiers,  Prev: Keywords,  Up: Identifiers and keywords

4.2.3.2 Soft Keywords
.....................

Added in version 3.10.

Some identifiers are only reserved under specific contexts.  These are
known as 'soft keywords'.  The identifiers ‘match’, ‘case’, ‘type’ and
‘_’ can syntactically act as keywords in certain contexts, but this
distinction is done at the parser level, not when tokenizing.

As soft keywords, their use in the grammar is possible while still
preserving compatibility with existing code that uses these names as
identifier names.

‘match’, ‘case’, and ‘_’ are used in the *note match: 813. statement.
‘type’ is used in the *note type: 43b. statement.

Changed in version 3.12: ‘type’ is now a soft keyword.


File: python.info,  Node: Reserved classes of identifiers,  Prev: Soft Keywords,  Up: Identifiers and keywords

4.2.3.3 Reserved classes of identifiers
.......................................

Certain classes of identifiers (besides keywords) have special meanings.
These classes are identified by the patterns of leading and trailing
underscore characters:

‘_*’

     Not imported by ‘from module import *’.

‘_’

     In a ‘case’ pattern within a *note match: 813. statement, ‘_’ is a
     *note soft keyword: 812. that denotes a *note wildcard: 814.

     Separately, the interactive interpreter makes the result of the
     last evaluation available in the variable ‘_’.  (It is stored in
     the *note builtins: 12. module, alongside built-in functions like
     ‘print’.)

     Elsewhere, ‘_’ is a regular identifier.  It is often used to name
     “special” items, but it is not special to Python itself.

          Note: The name ‘_’ is often used in conjunction with
          internationalization; refer to the documentation for the *note
          gettext: 63. module for more information on this convention.

          It is also commonly used for unused variables.

‘__*__’

     System-defined names, informally known as “dunder” names.  These
     names are defined by the interpreter and its implementation
     (including the standard library).  Current system names are
     discussed in the *note Special method names: c8f. section and
     elsewhere.  More will likely be defined in future versions of
     Python.  'Any' use of ‘__*__’ names, in any context, that does not
     follow explicitly documented use, is subject to breakage without
     warning.

‘__*’

     Class-private names.  Names in this category, when used within the
     context of a class definition, are re-written to use a mangled form
     to help avoid name clashes between “private” attributes of base and
     derived classes.  See section *note Identifiers (Names): 204c.


File: python.info,  Node: Literals,  Next: Operators,  Prev: Identifiers and keywords,  Up: Lexical analysis

4.2.4 Literals
--------------

Literals are notations for constant values of some built-in types.

* Menu:

* String and Bytes literals::
* String literal concatenation::
* f-strings::
* Numeric literals::
* Integer literals::
* Floating-point literals::
* Imaginary literals::


File: python.info,  Node: String and Bytes literals,  Next: String literal concatenation,  Up: Literals

4.2.4.1 String and Bytes literals
.................................

String literals are described by the following lexical definitions:

     stringliteral   ::= [*note stringprefix: 2052.](*note shortstring: 2053. | *note longstring: 2054.)
     stringprefix    ::= "r" | "u" | "R" | "U" | "f" | "F"
                         | "fr" | "Fr" | "fR" | "FR" | "rf" | "rF" | "Rf" | "RF"
     shortstring     ::= "'" *note shortstringitem: 2055.* "'" | '"' *note shortstringitem: 2055.* '"'
     longstring      ::= "'''" *note longstringitem: 2056.* "'''" | '"""' *note longstringitem: 2056.* '"""'
     shortstringitem ::= *note shortstringchar: 2057. | *note stringescapeseq: 2058.
     longstringitem  ::= *note longstringchar: 2059. | *note stringescapeseq: 2058.
     shortstringchar ::= <any source character except "\" or newline or the quote>
     longstringchar  ::= <any source character except "\">
     stringescapeseq ::= "\" <any source character>

     bytesliteral   ::= *note bytesprefix: 205b.(*note shortbytes: 205c. | *note longbytes: 205d.)
     bytesprefix    ::= "b" | "B" | "br" | "Br" | "bR" | "BR" | "rb" | "rB" | "Rb" | "RB"
     shortbytes     ::= "'" *note shortbytesitem: 205e.* "'" | '"' *note shortbytesitem: 205e.* '"'
     longbytes      ::= "'''" *note longbytesitem: 205f.* "'''" | '"""' *note longbytesitem: 205f.* '"""'
     shortbytesitem ::= *note shortbyteschar: 2060. | *note bytesescapeseq: 2061.
     longbytesitem  ::= *note longbyteschar: 2062. | *note bytesescapeseq: 2061.
     shortbyteschar ::= <any ASCII character except "\" or newline or the quote>
     longbyteschar  ::= <any ASCII character except "\">
     bytesescapeseq ::= "\" <any ASCII character>

One syntactic restriction not indicated by these productions is that
whitespace is not allowed between the *note stringprefix: 2052. or *note
bytesprefix: 205b. and the rest of the literal.  The source character
set is defined by the encoding declaration; it is UTF-8 if no encoding
declaration is given in the source file; see section *note Encoding
declarations: 2033.

In plain English: Both types of literals can be enclosed in matching
single quotes (‘'’) or double quotes (‘"’).  They can also be enclosed
in matching groups of three single or double quotes (these are generally
referred to as 'triple-quoted strings').  The backslash (‘\’) character
is used to give special meaning to otherwise ordinary characters like
‘n’, which means ‘newline’ when escaped (‘\n’).  It can also be used to
escape characters that otherwise have a special meaning, such as
newline, backslash itself, or the quote character.  See *note escape
sequences: 45d. below for examples.

Bytes literals are always prefixed with ‘'b'’ or ‘'B'’; they produce an
instance of the *note bytes: 1c2. type instead of the *note str: 44f.
type.  They may only contain ASCII characters; bytes with a numeric
value of 128 or greater must be expressed with escapes.

Both string and bytes literals may optionally be prefixed with a letter
‘'r'’ or ‘'R'’; such constructs are called 'raw string literals' and
'raw bytes literals' respectively and treat backslashes as literal
characters.  As a result, in raw string literals, ‘'\U'’ and ‘'\u'’
escapes are not treated specially.

Added in version 3.3: The ‘'rb'’ prefix of raw bytes literals has been
added as a synonym of ‘'br'’.

Support for the unicode legacy literal (‘u'value'’) was reintroduced to
simplify the maintenance of dual Python 2.x and 3.x codebases.  See PEP
414(1) for more information.

A string literal with ‘'f'’ or ‘'F'’ in its prefix is a 'formatted
string literal'; see *note f-strings: 9b4.  The ‘'f'’ may be combined
with ‘'r'’, but not with ‘'b'’ or ‘'u'’, therefore raw formatted strings
are possible, but formatted bytes literals are not.

In triple-quoted literals, unescaped newlines and quotes are allowed
(and are retained), except that three unescaped quotes in a row
terminate the literal.  (A “quote” is the character used to open the
literal, i.e.  either ‘'’ or ‘"’.)

* Menu:

* Escape sequences::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0414/


File: python.info,  Node: Escape sequences,  Up: String and Bytes literals

4.2.4.2 Escape sequences
........................

Unless an ‘'r'’ or ‘'R'’ prefix is present, escape sequences in string
and bytes literals are interpreted according to rules similar to those
used by Standard C. The recognized escape sequences are:

Escape Sequence               Meaning                               Notes
                                                                    
--------------------------------------------------------------------------------
                                                                    
‘\’<newline>                  Backslash and newline ignored         (1)
                                                                    
                                                                    
‘\\’                          Backslash (‘\’)
                              
                                                                    
‘\'’                          Single quote (‘'’)
                              
                                                                    
‘\"’                          Double quote (‘"’)
                              
                                                                    
‘\a’                          ASCII Bell (BEL)
                              
                                                                    
‘\b’                          ASCII Backspace (BS)
                              
                                                                    
‘\f’                          ASCII Formfeed (FF)
                              
                                                                    
‘\n’                          ASCII Linefeed (LF)
                              
                                                                    
‘\r’                          ASCII Carriage Return (CR)
                              
                                                                    
‘\t’                          ASCII Horizontal Tab (TAB)
                              
                                                                    
‘\v’                          ASCII Vertical Tab (VT)
                              
                                                                    
‘\OOO’                        Character with octal value 'ooo'      (2,4)
                                                                    
                                                                    
‘\xHH’                        Character with hex value 'hh'         (3,4)
                                                                    

Escape sequences only recognized in string literals are:

Escape Sequence               Meaning                               Notes
                                                                    
--------------------------------------------------------------------------------
                                                                    
‘\N{NAME}’                    Character named 'name' in the         (5)
                              Unicode database                      
                              
                                                                    
‘\uXXXX’                      Character with 16-bit hex value       (6)
                              'xxxx'                                
                              
                                                                    
‘\UXXXXXXXX’                  Character with 32-bit hex value       (7)
                              'xxxxxxxx'                            
                              

Notes:

  1. A backslash can be added at the end of a line to ignore the
     newline:

          >>> 'This string will not include \
          ... backslashes or newline characters.'
          'This string will not include backslashes or newline characters.'

     The same result can be achieved using *note triple-quoted strings:
     2050, or parentheses and *note string literal concatenation: 2064.

  2. As in Standard C, up to three octal digits are accepted.

     Changed in version 3.11: Octal escapes with value larger than
     ‘0o377’ produce a *note DeprecationWarning: 1a5.

     Changed in version 3.12: Octal escapes with value larger than
     ‘0o377’ produce a *note SyntaxWarning: 469.  In a future Python
     version they will be eventually a *note SyntaxError: 18d.

  3. Unlike in Standard C, exactly two hex digits are required.

  4. In a bytes literal, hexadecimal and octal escapes denote the byte
     with the given value.  In a string literal, these escapes denote a
     Unicode character with the given value.

  5. 
     Changed in version 3.3: Support for name aliases (1) has been
     added.

  6. Exactly four hex digits are required.

  7. Any Unicode character can be encoded this way.  Exactly eight hex
     digits are required.

Unlike Standard C, all unrecognized escape sequences are left in the
string unchanged, i.e., 'the backslash is left in the result'.  (This
behavior is useful when debugging: if an escape sequence is mistyped,
the resulting output is more easily recognized as broken.)  It is also
important to note that the escape sequences only recognized in string
literals fall into the category of unrecognized escapes for bytes
literals.

Changed in version 3.6: Unrecognized escape sequences produce a *note
DeprecationWarning: 1a5.

Changed in version 3.12: Unrecognized escape sequences produce a *note
SyntaxWarning: 469.  In a future Python version they will be eventually
a *note SyntaxError: 18d.

Even in a raw literal, quotes can be escaped with a backslash, but the
backslash remains in the result; for example, ‘r"\""’ is a valid string
literal consisting of two characters: a backslash and a double quote;
‘r"\"’ is not a valid string literal (even a raw string cannot end in an
odd number of backslashes).  Specifically, 'a raw literal cannot end in
a single backslash' (since the backslash would escape the following
quote character).  Note also that a single backslash followed by a
newline is interpreted as those two characters as part of the literal,
'not' as a line continuation.

   ---------- Footnotes ----------

   (1) ‘https://www.unicode.org/Public/15.1.0/ucd/NameAliases.txt’


File: python.info,  Node: String literal concatenation,  Next: f-strings,  Prev: String and Bytes literals,  Up: Literals

4.2.4.3 String literal concatenation
....................................

Multiple adjacent string or bytes literals (delimited by whitespace),
possibly using different quoting conventions, are allowed, and their
meaning is the same as their concatenation.  Thus, ‘"hello" 'world'’ is
equivalent to ‘"helloworld"’.  This feature can be used to reduce the
number of backslashes needed, to split long strings conveniently across
long lines, or even to add comments to parts of strings, for example:

     re.compile("[A-Za-z_]"       # letter or underscore
                "[A-Za-z0-9_]*"   # letter, digit or underscore
               )

Note that this feature is defined at the syntactical level, but
implemented at compile time.  The ‘+’ operator must be used to
concatenate string expressions at run time.  Also note that literal
concatenation can use different quoting styles for each component (even
mixing raw strings and triple quoted strings), and formatted string
literals may be concatenated with plain string literals.


File: python.info,  Node: f-strings,  Next: Numeric literals,  Prev: String literal concatenation,  Up: Literals

4.2.4.4 f-strings
.................

Added in version 3.6.

A 'formatted string literal' or 'f-string' is a string literal that is
prefixed with ‘'f'’ or ‘'F'’.  These strings may contain replacement
fields, which are expressions delimited by curly braces ‘{}’.  While
other string literals always have a constant value, formatted strings
are really expressions evaluated at run time.

Escape sequences are decoded like in ordinary string literals (except
when a literal is also marked as a raw string).  After decoding, the
grammar for the contents of the string is:

     f_string          ::= (*note literal_char: 2069. | "{{" | "}}" | *note replacement_field: 206a.)*
     replacement_field ::= "{" *note f_expression: 206b. ["="] ["!" *note conversion: 206c.] [":" *note format_spec: 206d.] "}"
     f_expression      ::= (*note conditional_expression: 206e. | "*" *note or_expr: 206f.)
                           ("," *note conditional_expression: 206e. | "," "*" *note or_expr: 206f.)* [","]
                           | *note yield_expression: 2070.
     conversion        ::= "s" | "r" | "a"
     format_spec       ::= (*note literal_char: 2069. | *note replacement_field: 206a.)*
     literal_char      ::= <any code point except "{", "}" or NULL>

The parts of the string outside curly braces are treated literally,
except that any doubled curly braces ‘'{{'’ or ‘'}}'’ are replaced with
the corresponding single curly brace.  A single opening curly bracket
‘'{'’ marks a replacement field, which starts with a Python expression.
To display both the expression text and its value after evaluation,
(useful in debugging), an equal sign ‘'='’ may be added after the
expression.  A conversion field, introduced by an exclamation point
‘'!'’ may follow.  A format specifier may also be appended, introduced
by a colon ‘':'’.  A replacement field ends with a closing curly bracket
‘'}'’.

Expressions in formatted string literals are treated like regular Python
expressions surrounded by parentheses, with a few exceptions.  An empty
expression is not allowed, and both *note lambda: 12e4. and assignment
expressions ‘:=’ must be surrounded by explicit parentheses.  Each
expression is evaluated in the context where the formatted string
literal appears, in order from left to right.  Replacement expressions
can contain newlines in both single-quoted and triple-quoted f-strings
and they can contain comments.  Everything that comes after a ‘#’ inside
a replacement field is a comment (even closing braces and quotes).  In
that case, replacement fields must be closed in a different line.

     >>> f"abc{a # This is a comment }"
     ... + 3}"
     'abc5'

Changed in version 3.7: Prior to Python 3.7, an *note await: 1b9.
expression and comprehensions containing an *note async for: ac0. clause
were illegal in the expressions in formatted string literals due to a
problem with the implementation.

Changed in version 3.12: Prior to Python 3.12, comments were not allowed
inside f-string replacement fields.

When the equal sign ‘'='’ is provided, the output will have the
expression text, the ‘'='’ and the evaluated value.  Spaces after the
opening brace ‘'{'’, within the expression and after the ‘'='’ are all
retained in the output.  By default, the ‘'='’ causes the *note repr():
803. of the expression to be provided, unless there is a format
specified.  When a format is specified it defaults to the *note str():
44f. of the expression unless a conversion ‘'!r'’ is declared.

Added in version 3.8: The equal sign ‘'='’.

If a conversion is specified, the result of evaluating the expression is
converted before formatting.  Conversion ‘'!s'’ calls *note str(): 44f.
on the result, ‘'!r'’ calls *note repr(): 803, and ‘'!a'’ calls *note
ascii(): 1434.

The result is then formatted using the *note format(): 622. protocol.
The format specifier is passed to the *note __format__(): 621. method of
the expression or conversion result.  An empty string is passed when the
format specifier is omitted.  The formatted result is then included in
the final value of the whole string.

Top-level format specifiers may include nested replacement fields.
These nested fields may include their own conversion fields and *note
format specifiers: 1e8, but may not include more deeply nested
replacement fields.  The *note format specifier mini-language: 1e8. is
the same as that used by the *note str.format(): 624. method.

Formatted string literals may be concatenated, but replacement fields
cannot be split across literals.

Some examples of formatted string literals:

     >>> name = "Fred"
     >>> f"He said his name is {name!r}."
     "He said his name is 'Fred'."
     >>> f"He said his name is {repr(name)}."  # repr() is equivalent to !r
     "He said his name is 'Fred'."
     >>> width = 10
     >>> precision = 4
     >>> value = decimal.Decimal("12.34567")
     >>> f"result: {value:{width}.{precision}}"  # nested fields
     'result:      12.35'
     >>> today = datetime(year=2017, month=1, day=27)
     >>> f"{today:%B %d, %Y}"  # using date format specifier
     'January 27, 2017'
     >>> f"{today=:%B %d, %Y}" # using date format specifier and debugging
     'today=January 27, 2017'
     >>> number = 1024
     >>> f"{number:#0x}"  # using integer format specifier
     '0x400'
     >>> foo = "bar"
     >>> f"{ foo = }" # preserves whitespace
     " foo = 'bar'"
     >>> line = "The mill's closed"
     >>> f"{line = }"
     'line = "The mill\'s closed"'
     >>> f"{line = :20}"
     "line = The mill's closed   "
     >>> f"{line = !r:20}"
     'line = "The mill\'s closed" '

Reusing the outer f-string quoting type inside a replacement field is
permitted:

     >>> a = dict(x=2)
     >>> f"abc {a["x"]} def"
     'abc 2 def'

Changed in version 3.12: Prior to Python 3.12, reuse of the same quoting
type of the outer f-string inside a replacement field was not possible.

Backslashes are also allowed in replacement fields and are evaluated the
same way as in any other context:

     >>> a = ["a", "b", "c"]
     >>> print(f"List a contains:\n{"\n".join(a)}")
     List a contains:
     a
     b
     c

Changed in version 3.12: Prior to Python 3.12, backslashes were not
permitted inside an f-string replacement field.

Formatted string literals cannot be used as docstrings, even if they do
not include expressions.

     >>> def foo():
     ...     f"Not a docstring"
     ...
     >>> foo.__doc__ is None
     True

See also PEP 498(1) for the proposal that added formatted string
literals, and *note str.format(): 624, which uses a related format
string mechanism.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0498/


File: python.info,  Node: Numeric literals,  Next: Integer literals,  Prev: f-strings,  Up: Literals

4.2.4.5 Numeric literals
........................

There are three types of numeric literals: integers, floating-point
numbers, and imaginary numbers.  There are no complex literals (complex
numbers can be formed by adding a real number and an imaginary number).

Note that numeric literals do not include a sign; a phrase like ‘-1’ is
actually an expression composed of the unary operator ‘‘-’’ and the
literal ‘1’.


File: python.info,  Node: Integer literals,  Next: Floating-point literals,  Prev: Numeric literals,  Up: Literals

4.2.4.6 Integer literals
........................

Integer literals are described by the following lexical definitions:

     integer      ::= *note decinteger: 2076. | *note bininteger: 2077. | *note octinteger: 2078. | *note hexinteger: 2079.
     decinteger   ::= *note nonzerodigit: 207a. (["_"] *note digit: 207b.)* | "0"+ (["_"] "0")*
     bininteger   ::= "0" ("b" | "B") (["_"] *note bindigit: 207c.)+
     octinteger   ::= "0" ("o" | "O") (["_"] *note octdigit: 207d.)+
     hexinteger   ::= "0" ("x" | "X") (["_"] *note hexdigit: 207e.)+
     nonzerodigit ::= "1"..."9"
     digit        ::= "0"..."9"
     bindigit     ::= "0" | "1"
     octdigit     ::= "0"..."7"
     hexdigit     ::= *note digit: 207b. | "a"..."f" | "A"..."F"

There is no limit for the length of integer literals apart from what can
be stored in available memory.

Underscores are ignored for determining the numeric value of the
literal.  They can be used to group digits for enhanced readability.
One underscore can occur between digits, and after base specifiers like
‘0x’.

Note that leading zeros in a non-zero decimal number are not allowed.
This is for disambiguation with C-style octal literals, which Python
used before version 3.0.

Some examples of integer literals:

     7     2147483647                        0o177    0b100110111
     3     79228162514264337593543950336     0o377    0xdeadbeef
           100_000_000_000                   0b_1110_0101

Changed in version 3.6: Underscores are now allowed for grouping
purposes in literals.


File: python.info,  Node: Floating-point literals,  Next: Imaginary literals,  Prev: Integer literals,  Up: Literals

4.2.4.7 Floating-point literals
...............................

Floating-point literals are described by the following lexical
definitions:

     floatnumber   ::= *note pointfloat: 2082. | *note exponentfloat: 2083.
     pointfloat    ::= [*note digitpart: 2084.] *note fraction: 2085. | *note digitpart: 2084. "."
     exponentfloat ::= (*note digitpart: 2084. | *note pointfloat: 2082.) *note exponent: 2086.
     digitpart     ::= *note digit: 207b. (["_"] *note digit: 207b.)*
     fraction      ::= "." *note digitpart: 2084.
     exponent      ::= ("e" | "E") ["+" | "-"] *note digitpart: 2084.

Note that the integer and exponent parts are always interpreted using
radix 10.  For example, ‘077e010’ is legal, and denotes the same number
as ‘77e10’.  The allowed range of floating-point literals is
implementation-dependent.  As in integer literals, underscores are
supported for digit grouping.

Some examples of floating-point literals:

     3.14    10.    .001    1e100    3.14e-10    0e0    3.14_15_93

Changed in version 3.6: Underscores are now allowed for grouping
purposes in literals.


File: python.info,  Node: Imaginary literals,  Prev: Floating-point literals,  Up: Literals

4.2.4.8 Imaginary literals
..........................

Imaginary literals are described by the following lexical definitions:

     imagnumber ::= (*note floatnumber: 2081. | *note digitpart: 2084.) ("j" | "J")

An imaginary literal yields a complex number with a real part of 0.0.
Complex numbers are represented as a pair of floating-point numbers and
have the same restrictions on their range.  To create a complex number
with a nonzero real part, add a floating-point number to it, e.g.,
‘(3+4j)’.  Some examples of imaginary literals:

     3.14j   10.j    10j     .001j   1e100j   3.14e-10j   3.14_15_93j


File: python.info,  Node: Operators,  Next: Delimiters,  Prev: Literals,  Up: Lexical analysis

4.2.5 Operators
---------------

The following tokens are operators:

     +       -       *       **      /       //      %      @
     <<      >>      &       |       ^       ~       :=
     <       >       <=      >=      ==      !=


File: python.info,  Node: Delimiters,  Prev: Operators,  Up: Lexical analysis

4.2.6 Delimiters
----------------

The following tokens serve as delimiters in the grammar:

     (       )       [       ]       {       }
     ,       :       !       .       ;       @       =
     ->      +=      -=      *=      /=      //=     %=
     @=      &=      |=      ^=      >>=     <<=     **=

The period can also occur in floating-point and imaginary literals.  A
sequence of three periods has a special meaning as an ellipsis literal.
The second half of the list, the augmented assignment operators, serve
lexically as delimiters, but also perform an operation.

The following printing ASCII characters have special meaning as part of
other tokens or are otherwise significant to the lexical analyzer:

     '       "       #       \

The following printing ASCII characters are not used in Python.  Their
occurrence outside string literals and comments is an unconditional
error:

     $       ?       `


File: python.info,  Node: Data model,  Next: Execution model,  Prev: Lexical analysis,  Up: The Python Language Reference

4.3 Data model
==============

* Menu:

* Objects, values and types: Objects values and types.
* The standard type hierarchy::
* Special method names::
* Coroutines::


File: python.info,  Node: Objects values and types,  Next: The standard type hierarchy,  Up: Data model

4.3.1 Objects, values and types
-------------------------------

'Objects' are Python’s abstraction for data.  All data in a Python
program is represented by objects or by relations between objects.  Even
code is represented by objects.

Every object has an identity, a type and a value.  An object’s
'identity' never changes once it has been created; you may think of it
as the object’s address in memory.  The *note is: 2f5. operator compares
the identity of two objects; the *note id(): 1471. function returns an
integer representing its identity.

'CPython implementation detail:' For CPython, ‘id(x)’ is the memory
address where ‘x’ is stored.

An object’s type determines the operations that the object supports
(e.g., “does it have a length?”) and also defines the possible values
for objects of that type.  The *note type(): d71. function returns an
object’s type (which is an object itself).  Like its identity, an
object’s 'type' is also unchangeable.  (1)

The 'value' of some objects can change.  Objects whose value can change
are said to be 'mutable'; objects whose value is unchangeable once they
are created are called 'immutable'.  (The value of an immutable
container object that contains a reference to a mutable object can
change when the latter’s value is changed; however the container is
still considered immutable, because the collection of objects it
contains cannot be changed.  So, immutability is not strictly the same
as having an unchangeable value, it is more subtle.)  An object’s
mutability is determined by its type; for instance, numbers, strings and
tuples are immutable, while dictionaries and lists are mutable.

Objects are never explicitly destroyed; however, when they become
unreachable they may be garbage-collected.  An implementation is allowed
to postpone garbage collection or omit it altogether — it is a matter of
implementation quality how garbage collection is implemented, as long as
no objects are collected that are still reachable.

'CPython implementation detail:' CPython currently uses a
reference-counting scheme with (optional) delayed detection of
cyclically linked garbage, which collects most objects as soon as they
become unreachable, but is not guaranteed to collect garbage containing
circular references.  See the documentation of the *note gc: 60. module
for information on controlling the collection of cyclic garbage.  Other
implementations act differently and CPython may change.  Do not depend
on immediate finalization of objects when they become unreachable (so
you should always close files explicitly).

Note that the use of the implementation’s tracing or debugging
facilities may keep objects alive that would normally be collectable.
Also note that catching an exception with a *note try: 6ec.…*note
except: 18b. statement may keep objects alive.

Some objects contain references to “external” resources such as open
files or windows.  It is understood that these resources are freed when
the object is garbage-collected, but since garbage collection is not
guaranteed to happen, such objects also provide an explicit way to
release the external resource, usually a ‘close()’ method.  Programs are
strongly recommended to explicitly close such objects.  The *note try:
6ec.…*note finally: 9d5. statement and the *note with: 5d5. statement
provide convenient ways to do this.

Some objects contain references to other objects; these are called
'containers'.  Examples of containers are tuples, lists and
dictionaries.  The references are part of a container’s value.  In most
cases, when we talk about the value of a container, we imply the values,
not the identities of the contained objects; however, when we talk about
the mutability of a container, only the identities of the immediately
contained objects are implied.  So, if an immutable container (like a
tuple) contains a reference to a mutable object, its value changes if
that mutable object is changed.

Types affect almost all aspects of object behavior.  Even the importance
of object identity is affected in some sense: for immutable types,
operations that compute new values may actually return a reference to
any existing object with the same type and value, while for mutable
objects this is not allowed.  For example, after ‘a = 1; b = 1’, 'a' and
'b' may or may not refer to the same object with the value one,
depending on the implementation.  This is because *note int: 257. is an
immutable type, so the reference to ‘1’ can be reused.  This behaviour
depends on the implementation used, so should not be relied upon, but is
something to be aware of when making use of object identity tests.
However, after ‘c = []; d = []’, 'c' and 'd' are guaranteed to refer to
two different, unique, newly created empty lists.  (Note that ‘e = f =
[]’ assigns the 'same' object to both 'e' and 'f'.)

   ---------- Footnotes ----------

   (1) It 'is' possible in some cases to change an object’s type, under
certain controlled conditions.  It generally isn’t a good idea though,
since it can lead to some very strange behaviour if it is handled
incorrectly.


File: python.info,  Node: The standard type hierarchy,  Next: Special method names,  Prev: Objects values and types,  Up: Data model

4.3.2 The standard type hierarchy
---------------------------------

Below is a list of the types that are built into Python.  Extension
modules (written in C, Java, or other languages, depending on the
implementation) can define additional types.  Future versions of Python
may add types to the type hierarchy (e.g., rational numbers, efficiently
stored arrays of integers, etc.), although such additions will often be
provided via the standard library instead.

Some of the type descriptions below contain a paragraph listing ‘special
attributes.’ These are attributes that provide access to the
implementation and are not intended for general use.  Their definition
may change in the future.

* Menu:

* None::
* NotImplemented::
* Ellipsis::
* numbers.Number: numbers Number.
* Sequences::
* Set types::
* Mappings::
* Callable types::
* Modules: Modules<3>.
* Custom classes::
* Class instances::
* I/O objects (also known as file objects): I/O objects also known as file objects.
* Internal types::


File: python.info,  Node: None,  Next: NotImplemented,  Up: The standard type hierarchy

4.3.2.1 None
............

This type has a single value.  There is a single object with this value.
This object is accessed through the built-in name ‘None’.  It is used to
signify the absence of a value in many situations, e.g., it is returned
from functions that don’t explicitly return anything.  Its truth value
is false.


File: python.info,  Node: NotImplemented,  Next: Ellipsis,  Prev: None,  Up: The standard type hierarchy

4.3.2.2 NotImplemented
......................

This type has a single value.  There is a single object with this value.
This object is accessed through the built-in name *note NotImplemented:
7d6.  Numeric methods and rich comparison methods should return this
value if they do not implement the operation for the operands provided.
(The interpreter will then try the reflected operation, or some other
fallback, depending on the operator.)  It should not be evaluated in a
boolean context.

See *note Implementing the arithmetic operations: 2097. for more
details.

Changed in version 3.9: Evaluating *note NotImplemented: 7d6. in a
boolean context is deprecated.  While it currently evaluates as true, it
will emit a *note DeprecationWarning: 1a5.  It will raise a *note
TypeError: 2c3. in a future version of Python.


File: python.info,  Node: Ellipsis,  Next: numbers Number,  Prev: NotImplemented,  Up: The standard type hierarchy

4.3.2.3 Ellipsis
................

This type has a single value.  There is a single object with this value.
This object is accessed through the literal ‘...’ or the built-in name
‘Ellipsis’.  Its truth value is true.


File: python.info,  Node: numbers Number,  Next: Sequences,  Prev: Ellipsis,  Up: The standard type hierarchy

4.3.2.4 ‘numbers.Number’
........................

These are created by numeric literals and returned as results by
arithmetic operators and arithmetic built-in functions.  Numeric objects
are immutable; once created their value never changes.  Python numbers
are of course strongly related to mathematical numbers, but subject to
the limitations of numerical representation in computers.

The string representations of the numeric classes, computed by *note
__repr__(): 61f. and *note __str__(): 620, have the following
properties:

   * They are valid numeric literals which, when passed to their class
     constructor, produce an object having the value of the original
     numeric.

   * The representation is in base 10, when possible.

   * Leading zeros, possibly excepting a single zero before a decimal
     point, are not shown.

   * Trailing zeros, possibly excepting a single zero after a decimal
     point, are not shown.

   * A sign is shown only when the number is negative.

Python distinguishes between integers, floating-point numbers, and
complex numbers:

* Menu:

* numbers.Integral: numbers Integral.
* numbers.Real (float): numbers Real float.
* numbers.Complex (complex): numbers Complex complex.


File: python.info,  Node: numbers Integral,  Next: numbers Real float,  Up: numbers Number

4.3.2.5 ‘numbers.Integral’
..........................

These represent elements from the mathematical set of integers (positive
and negative).

     Note: 
     The rules for integer representation are intended to give the most
     meaningful interpretation of shift and mask operations involving
     negative integers.

There are two types of integers:

Integers (*note int: 257.)

     These represent numbers in an unlimited range, subject to available
     (virtual) memory only.  For the purpose of shift and mask
     operations, a binary representation is assumed, and negative
     numbers are represented in a variant of 2’s complement which gives
     the illusion of an infinite string of sign bits extending to the
     left.

Booleans (*note bool: 46b.)

     These represent the truth values False and True.  The two objects
     representing the values ‘False’ and ‘True’ are the only Boolean
     objects.  The Boolean type is a subtype of the integer type, and
     Boolean values behave like the values 0 and 1, respectively, in
     almost all contexts, the exception being that when converted to a
     string, the strings ‘"False"’ or ‘"True"’ are returned,
     respectively.


File: python.info,  Node: numbers Real float,  Next: numbers Complex complex,  Prev: numbers Integral,  Up: numbers Number

4.3.2.6 ‘numbers.Real’ (‘float’)
................................

These represent machine-level double precision floating-point numbers.
You are at the mercy of the underlying machine architecture (and C or
Java implementation) for the accepted range and handling of overflow.
Python does not support single-precision floating-point numbers; the
savings in processor and memory usage that are usually the reason for
using these are dwarfed by the overhead of using objects in Python, so
there is no reason to complicate the language with two kinds of
floating-point numbers.


File: python.info,  Node: numbers Complex complex,  Prev: numbers Real float,  Up: numbers Number

4.3.2.7 ‘numbers.Complex’ (‘complex’)
.....................................

These represent complex numbers as a pair of machine-level double
precision floating-point numbers.  The same caveats apply as for
floating-point numbers.  The real and imaginary parts of a complex
number ‘z’ can be retrieved through the read-only attributes ‘z.real’
and ‘z.imag’.


File: python.info,  Node: Sequences,  Next: Set types,  Prev: numbers Number,  Up: The standard type hierarchy

4.3.2.8 Sequences
.................

These represent finite ordered sets indexed by non-negative numbers.
The built-in function *note len(): 631. returns the number of items of a
sequence.  When the length of a sequence is 'n', the index set contains
the numbers 0, 1, …, 'n'-1.  Item 'i' of sequence 'a' is selected by
‘a[i]’.  Some sequences, including built-in sequences, interpret
negative subscripts by adding the sequence length.  For example, ‘a[-2]’
equals ‘a[n-2]’, the second to last item of sequence a with length ‘n’.

Sequences also support slicing: ‘a[i:j]’ selects all items with index
'k' such that 'i' ‘<=’ 'k' ‘<’ 'j'.  When used as an expression, a slice
is a sequence of the same type.  The comment above about negative
indexes also applies to negative slice positions.

Some sequences also support “extended slicing” with a third “step”
parameter: ‘a[i:j:k]’ selects all items of 'a' with index 'x' where ‘x =
i + n*k’, 'n' ‘>=’ ‘0’ and 'i' ‘<=’ 'x' ‘<’ 'j'.

Sequences are distinguished according to their mutability:

* Menu:

* Immutable sequences::
* Mutable sequences::


File: python.info,  Node: Immutable sequences,  Next: Mutable sequences,  Up: Sequences

4.3.2.9 Immutable sequences
...........................

An object of an immutable sequence type cannot change once it is
created.  (If the object contains references to other objects, these
other objects may be mutable and may be changed; however, the collection
of objects directly referenced by an immutable object cannot change.)

The following types are immutable sequences:

Strings

     A string is a sequence of values that represent Unicode code
     points.  All the code points in the range ‘U+0000 - U+10FFFF’ can
     be represented in a string.  Python doesn’t have a char type;
     instead, every code point in the string is represented as a string
     object with length ‘1’.  The built-in function *note ord(): 209f.
     converts a code point from its string form to an integer in the
     range ‘0 - 10FFFF’; *note chr(): 1785. converts an integer in the
     range ‘0 - 10FFFF’ to the corresponding length ‘1’ string object.
     *note str.encode(): 8de. can be used to convert a *note str: 44f.
     to *note bytes: 1c2. using the given text encoding, and *note
     bytes.decode(): 8df. can be used to achieve the opposite.

Tuples

     The items of a tuple are arbitrary Python objects.  Tuples of two
     or more items are formed by comma-separated lists of expressions.
     A tuple of one item (a ‘singleton’) can be formed by affixing a
     comma to an expression (an expression by itself does not create a
     tuple, since parentheses must be usable for grouping of
     expressions).  An empty tuple can be formed by an empty pair of
     parentheses.

Bytes

     A bytes object is an immutable array.  The items are 8-bit bytes,
     represented by integers in the range 0 <= x < 256.  Bytes literals
     (like ‘b'abc'’) and the built-in *note bytes(): 1c2. constructor
     can be used to create bytes objects.  Also, bytes objects can be
     decoded to strings via the *note decode(): 8df. method.


File: python.info,  Node: Mutable sequences,  Prev: Immutable sequences,  Up: Sequences

4.3.2.10 Mutable sequences
..........................

Mutable sequences can be changed after they are created.  The
subscription and slicing notations can be used as the target of
assignment and *note del: 18c2. (delete) statements.

     Note: 
     The *note collections: 1d. and *note array: 7. module provide
     additional examples of mutable sequence types.

There are currently two intrinsic mutable sequence types:

Lists

     The items of a list are arbitrary Python objects.  Lists are formed
     by placing a comma-separated list of expressions in square
     brackets.  (Note that there are no special cases needed to form
     lists of length 0 or 1.)

Byte Arrays

     A bytearray object is a mutable array.  They are created by the
     built-in *note bytearray(): 2ea. constructor.  Aside from being
     mutable (and hence unhashable), byte arrays otherwise provide the
     same interface and functionality as immutable *note bytes: 1c2.
     objects.


File: python.info,  Node: Set types,  Next: Mappings,  Prev: Sequences,  Up: The standard type hierarchy

4.3.2.11 Set types
..................

These represent unordered, finite sets of unique, immutable objects.  As
such, they cannot be indexed by any subscript.  However, they can be
iterated over, and the built-in function *note len(): 631. returns the
number of items in a set.  Common uses for sets are fast membership
testing, removing duplicates from a sequence, and computing mathematical
operations such as intersection, union, difference, and symmetric
difference.

For set elements, the same immutability rules apply as for dictionary
keys.  Note that numeric types obey the normal rules for numeric
comparison: if two numbers compare equal (e.g., ‘1’ and ‘1.0’), only one
of them can be contained in a set.

There are currently two intrinsic set types:

Sets

     These represent a mutable set.  They are created by the built-in
     *note set(): 5dc. constructor and can be modified afterwards by
     several methods, such as *note add(): 20a2.

Frozen sets

     These represent an immutable set.  They are created by the built-in
     *note frozenset(): 5dd. constructor.  As a frozenset is immutable
     and *note hashable: 613, it can be used again as an element of
     another set, or as a dictionary key.


File: python.info,  Node: Mappings,  Next: Callable types,  Prev: Set types,  Up: The standard type hierarchy

4.3.2.12 Mappings
.................

These represent finite sets of objects indexed by arbitrary index sets.
The subscript notation ‘a[k]’ selects the item indexed by ‘k’ from the
mapping ‘a’; this can be used in expressions and as the target of
assignments or *note del: 18c2. statements.  The built-in function *note
len(): 631. returns the number of items in a mapping.

There is currently a single intrinsic mapping type:

* Menu:

* Dictionaries: Dictionaries<2>.


File: python.info,  Node: Dictionaries<2>,  Up: Mappings

4.3.2.13 Dictionaries
.....................

These represent finite sets of objects indexed by nearly arbitrary
values.  The only types of values not acceptable as keys are values
containing lists or dictionaries or other mutable types that are
compared by value rather than by object identity, the reason being that
the efficient implementation of dictionaries requires a key’s hash value
to remain constant.  Numeric types used for keys obey the normal rules
for numeric comparison: if two numbers compare equal (e.g., ‘1’ and
‘1.0’) then they can be used interchangeably to index the same
dictionary entry.

Dictionaries preserve insertion order, meaning that keys will be
produced in the same order they were added sequentially over the
dictionary.  Replacing an existing key does not change the order,
however removing a key and re-inserting it will add it to the end
instead of keeping its old place.

Dictionaries are mutable; they can be created by the ‘{}’ notation (see
section *note Dictionary displays: dad.).

The extension modules *note dbm.ndbm: 34. and *note dbm.gnu: 33. provide
additional examples of mapping types, as does the *note collections: 1d.
module.

Changed in version 3.7: Dictionaries did not preserve insertion order in
versions of Python before 3.6.  In CPython 3.6, insertion order was
preserved, but it was considered an implementation detail at that time
rather than a language guarantee.


File: python.info,  Node: Callable types,  Next: Modules<3>,  Prev: Mappings,  Up: The standard type hierarchy

4.3.2.14 Callable types
.......................

These are the types to which the function call operation (see section
*note Calls: dab.) can be applied:

* Menu:

* User-defined functions::
* Instance methods::
* Generator functions::
* Coroutine functions::
* Asynchronous generator functions::
* Built-in functions::
* Built-in methods::
* Classes: Classes<2>.
* Class Instances::


File: python.info,  Node: User-defined functions,  Next: Instance methods,  Up: Callable types

4.3.2.15 User-defined functions
...............................

A user-defined function object is created by a function definition (see
section *note Function definitions: 1dce.).  It should be called with an
argument list containing the same number of items as the function’s
formal parameter list.

* Menu:

* Special read-only attributes::
* Special writable attributes::


File: python.info,  Node: Special read-only attributes,  Next: Special writable attributes,  Up: User-defined functions

4.3.2.16 Special read-only attributes
.....................................

Attribute                                              Meaning
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- Attribute: function.__builtins__                   A reference to the *note dictionary: 256. that holds
                                                       the function’s builtins namespace.
                                                       
                                                       Added in version 3.10.
                                                       
                                                       
 -- Attribute: function.__globals__                    A reference to the *note dictionary: 256. that holds
                                                       the function’s *note global variables: 20a9. – the
                                                       global namespace of the module in which the function
                                                       was defined.
                                                       
                                                       
 -- Attribute: function.__closure__                    ‘None’ or a *note tuple: 373. of cells that contain
                                                       bindings for the names specified in the
                                                       *note co_freevars: 20aa. attribute of the function’s
                                                       *note code object: 29a.
                                                       
                                                       A cell object has the attribute ‘cell_contents’.
                                                       This can be used to get the value of the cell, as
                                                       well as set the value.
                                                       


File: python.info,  Node: Special writable attributes,  Prev: Special read-only attributes,  Up: User-defined functions

4.3.2.17 Special writable attributes
....................................

Most of these attributes check the type of the assigned value:

Attribute                                              Meaning
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- Attribute: function.__doc__                        The function’s documentation string, or ‘None’ if
                                                       unavailable.
                                                       
                                                       
 -- Attribute: function.__name__                       The function’s name.  See also:
                                                       *note __name__ attributes: 10a4.
                                                       
                                                       
 -- Attribute: function.__qualname__                   The function’s *note qualified name: 1acb.  See
                                                       also: *note __qualname__ attributes: 10a3.
                                                       
                                                       Added in version 3.3.
                                                       
                                                       
 -- Attribute: function.__module__                     The name of the module the function was defined in,
                                                       or ‘None’ if unavailable.
                                                       
                                                       
 -- Attribute: function.__defaults__                   A *note tuple: 373. containing default
                                                       *note parameter: 20ae. values for those parameters
                                                       that have defaults, or ‘None’ if no parameters have
                                                       a default value.
                                                       
                                                       
 -- Attribute: function.__code__                       The *note code object: 1d2. representing the
                                                       compiled function body.
                                                       
                                                       
 -- Attribute: function.__dict__                       The namespace supporting arbitrary function
                                                       attributes.  See also:
                                                       *note __dict__ attributes: 55e.
                                                       
                                                       
 -- Attribute: function.__annotations__                A *note dictionary: 256. containing annotations of
                                                       *note parameters: 20ae.  The keys of the dictionary
                                                       are the parameter names, and ‘'return'’ for the
                                                       return annotation, if provided.  See also:
                                                       *note Annotations Best Practices: 7dd.
                                                       
                                                       
 -- Attribute: function.__kwdefaults__                 A *note dictionary: 256. containing defaults for
                                                       keyword-only *note parameters: 20ae.
                                                       
                                                       
 -- Attribute: function.__type_params__                A *note tuple: 373. containing the
                                                       *note type parameters: 2b3. of a
                                                       *note generic function: 456.
                                                       
                                                       Added in version 3.12.
                                                       

Function objects also support getting and setting arbitrary attributes,
which can be used, for example, to attach metadata to functions.
Regular attribute dot-notation is used to get and set such attributes.

'CPython implementation detail:' CPython’s current implementation only
supports function attributes on user-defined functions.  Function
attributes on *note built-in functions: 20b0. may be supported in the
future.

Additional information about a function’s definition can be retrieved
from its *note code object: 1d2. (accessible via the *note __code__:
29a. attribute).


File: python.info,  Node: Instance methods,  Next: Generator functions,  Prev: User-defined functions,  Up: Callable types

4.3.2.18 Instance methods
.........................

An instance method object combines a class, a class instance and any
callable object (normally a user-defined function).

Special read-only attributes:

 -- Attribute: method.__self__                         Refers to the class instance object to which the
                                                       method is *note bound: 20b2.
                                                       
                                                       
 -- Attribute: method.__func__                         Refers to the original *note function object: 299.
                                                       
                                                       
 -- Attribute: method.__doc__                          The method’s documentation (same as
                                                       *note method.__func__.__doc__: 121e.).  A
                                                       *note string: 44f. if the original function had a
                                                       docstring, else ‘None’.
                                                       
                                                       
 -- Attribute: method.__name__                         The name of the method (same as
                                                       *note method.__func__.__name__: 131c.)
                                                       
                                                       
 -- Attribute: method.__module__                       The name of the module the method was defined in, or
                                                       ‘None’ if unavailable.
                                                       

Methods also support accessing (but not setting) the arbitrary function
attributes on the underlying *note function object: 299.

User-defined method objects may be created when getting an attribute of
a class (perhaps via an instance of that class), if that attribute is a
user-defined *note function object: 299. or a *note classmethod: 166.
object.  When an instance method object is created by retrieving a
user-defined *note function object: 299. from a class via one of its
instances, its *note __self__: 1415. attribute is the instance, and the
method object is said to be 'bound'.  The new method’s *note __func__:
1345. attribute is the original function object.

When an instance method object is created by retrieving a *note
classmethod: 166. object from a class or instance, its *note __self__:
1415. attribute is the class itself, and its *note __func__: 1345.
attribute is the function object underlying the class method.

When an instance method object is called, the underlying function (*note
__func__: 1345.) is called, inserting the class instance (*note
__self__: 1415.) in front of the argument list.  For instance, when ‘C’
is a class which contains a definition for a function ‘f()’, and ‘x’ is
an instance of ‘C’, calling ‘x.f(1)’ is equivalent to calling ‘C.f(x,
1)’.

When an instance method object is derived from a *note classmethod: 166.
object, the “class instance” stored in *note __self__: 1415. will
actually be the class itself, so that calling either ‘x.f(1)’ or
‘C.f(1)’ is equivalent to calling ‘f(C,1)’ where ‘f’ is the underlying
function.

It is important to note that user-defined functions which are attributes
of a class instance are not converted to bound methods; this 'only'
happens when the function is an attribute of the class.


File: python.info,  Node: Generator functions,  Next: Coroutine functions,  Prev: Instance methods,  Up: Callable types

4.3.2.19 Generator functions
............................

A function or method which uses the *note yield: 9d8. statement (see
section *note The yield statement: 9d8.) is called a 'generator
function'.  Such a function, when called, always returns an *note
iterator: 1ac. object which can be used to execute the body of the
function: calling the iterator’s *note iterator.__next__(): 1315. method
will cause the function to execute until it provides a value using the
‘yield’ statement.  When the function executes a *note return: 9d9.
statement or falls off the end, a *note StopIteration: c1b. exception is
raised and the iterator will have reached the end of the set of values
to be returned.


File: python.info,  Node: Coroutine functions,  Next: Asynchronous generator functions,  Prev: Generator functions,  Up: Callable types

4.3.2.20 Coroutine functions
............................

A function or method which is defined using *note async def: 5d4. is
called a 'coroutine function'.  Such a function, when called, returns a
*note coroutine: 494. object.  It may contain *note await: 1b9.
expressions, as well as *note async with: 5d8. and *note async for: ac0.
statements.  See also the *note Coroutine Objects: 20b8. section.


File: python.info,  Node: Asynchronous generator functions,  Next: Built-in functions,  Prev: Coroutine functions,  Up: Callable types

4.3.2.21 Asynchronous generator functions
.........................................

A function or method which is defined using *note async def: 5d4. and
which uses the *note yield: 9d8. statement is called a 'asynchronous
generator function'.  Such a function, when called, returns an *note
asynchronous iterator: 1ab. object which can be used in an *note async
for: ac0. statement to execute the body of the function.

Calling the asynchronous iterator’s *note aiterator.__anext__: 1678.
method will return an *note awaitable: 1ad. which when awaited will
execute until it provides a value using the *note yield: 9d8.
expression.  When the function executes an empty *note return: 9d9.
statement or falls off the end, a *note StopAsyncIteration: 1bbe.
exception is raised and the asynchronous iterator will have reached the
end of the set of values to be yielded.


File: python.info,  Node: Built-in functions,  Next: Built-in methods,  Prev: Asynchronous generator functions,  Up: Callable types

4.3.2.22 Built-in functions
...........................

A built-in function object is a wrapper around a C function.  Examples
of built-in functions are *note len(): 631. and *note math.sin(): 150d.
(*note math: 8e. is a standard built-in module).  The number and type of
the arguments are determined by the C function.  Special read-only
attributes:

   * ‘__doc__’ is the function’s documentation string, or ‘None’ if
     unavailable.  See *note function.__doc__: 121e.

   * ‘__name__’ is the function’s name.  See *note function.__name__:
     131c.

   * ‘__self__’ is set to ‘None’ (but see the next item).

   * ‘__module__’ is the name of the module the function was defined in
     or ‘None’ if unavailable.  See *note function.__module__: 20ad.


File: python.info,  Node: Built-in methods,  Next: Classes<2>,  Prev: Built-in functions,  Up: Callable types

4.3.2.23 Built-in methods
.........................

This is really a different disguise of a built-in function, this time
containing an object passed to the C function as an implicit extra
argument.  An example of a built-in method is ‘alist.append()’, assuming
'alist' is a list object.  In this case, the special read-only attribute
‘__self__’ is set to the object denoted by 'alist'.  (The attribute has
the same semantics as it does with *note other instance methods: 1415.)


File: python.info,  Node: Classes<2>,  Next: Class Instances,  Prev: Built-in methods,  Up: Callable types

4.3.2.24 Classes
................

Classes are callable.  These objects normally act as factories for new
instances of themselves, but variations are possible for class types
that override *note __new__(): 583.  The arguments of the call are
passed to ‘__new__()’ and, in the typical case, to *note __init__():
6b3. to initialize the new instance.


File: python.info,  Node: Class Instances,  Prev: Classes<2>,  Up: Callable types

4.3.2.25 Class Instances
........................

Instances of arbitrary classes can be made callable by defining a *note
__call__(): 55b. method in their class.


File: python.info,  Node: Modules<3>,  Next: Custom classes,  Prev: Callable types,  Up: The standard type hierarchy

4.3.2.26 Modules
................

Modules are a basic organizational unit of Python code, and are created
by the *note import system: 20c2. as invoked either by the *note import:
5e5. statement, or by calling functions such as *note
importlib.import_module(): 51b. and built-in *note __import__(): 8dd.  A
module object has a namespace implemented by a *note dictionary: 256.
object (this is the dictionary referenced by the *note __globals__:
131b. attribute of functions defined in the module).  Attribute
references are translated to lookups in this dictionary, e.g., ‘m.x’ is
equivalent to ‘m.__dict__["x"]’.  A module object does not contain the
code object used to initialize the module (since it isn’t needed once
the initialization is done).

Attribute assignment updates the module’s namespace dictionary, e.g.,
‘m.x = 1’ is equivalent to ‘m.__dict__["x"] = 1’.

* Menu:

* Import-related attributes on module objects::
* Other writable attributes on module objects::
* Module dictionaries::


File: python.info,  Node: Import-related attributes on module objects,  Next: Other writable attributes on module objects,  Up: Modules<3>

4.3.2.27 Import-related attributes on module objects
....................................................

Module objects have the following attributes that relate to the *note
import system: 20c2.  When a module is created using the machinery
associated with the import system, these attributes are filled in based
on the module’s *note spec: 20c5, before the *note loader: 17c1.
executes and loads the module.

To create a module dynamically rather than using the import system, it’s
recommended to use *note importlib.util.module_from_spec(): e44, which
will set the various import-controlled attributes to appropriate values.
It’s also possible to use the *note types.ModuleType: e45. constructor
to create modules directly, but this technique is more error-prone, as
most attributes must be manually set on the module object after it has
been created when using this approach.

     Caution: With the exception of *note __name__: 13d8, it is
     'strongly' recommended that you rely on *note __spec__: 20c6. and
     its attributes instead of any of the other individual attributes
     listed in this subsection.  Note that updating an attribute on
     ‘__spec__’ will not update the corresponding attribute on the
     module itself:

          >>> import typing
          >>> typing.__name__, typing.__spec__.name
          ('typing', 'typing')
          >>> typing.__spec__.name = 'spelling'
          >>> typing.__name__, typing.__spec__.name
          ('typing', 'spelling')
          >>> typing.__name__ = 'keyboard_smashing'
          >>> typing.__name__, typing.__spec__.name
          ('keyboard_smashing', 'spelling')

 -- Attribute: module.__name__

     The name used to uniquely identify the module in the import system.
     For a directly executed module, this will be set to ‘"__main__"’.

     This attribute must be set to the fully qualified name of the
     module.  It is expected to match the value of *note
     module.__spec__.name: 20c7.

 -- Attribute: module.__spec__

     A record of the module’s import-system-related state.

     Set to the *note module spec: 200d. that was used when importing
     the module.  See *note Module specs: 20c8. for more details.

     Added in version 3.4.

 -- Attribute: module.__package__

     The *note package: 20c9. a module belongs to.

     If the module is top-level (that is, not a part of any specific
     package) then the attribute should be set to ‘''’ (the empty
     string).  Otherwise, it should be set to the name of the module’s
     package (which can be equal to *note module.__name__: 13d8. if the
     module itself is a package).  See PEP 366(1) for further details.

     This attribute is used instead of *note __name__: 13d8. to
     calculate explicit relative imports for main modules.  It defaults
     to ‘None’ for modules created dynamically using the *note
     types.ModuleType: e45. constructor; use *note
     importlib.util.module_from_spec(): e44. instead to ensure the
     attribute is set to a *note str: 44f.

     It is 'strongly' recommended that you use *note
     module.__spec__.parent: 2d8. instead of ‘module.__package__’.
     *note __package__: 2d7. is now only used as a fallback if
     ‘__spec__.parent’ is not set, and this fallback path is deprecated.

     Changed in version 3.4: This attribute now defaults to ‘None’ for
     modules created dynamically using the *note types.ModuleType: e45.
     constructor.  Previously the attribute was optional.

     Changed in version 3.6: The value of ‘__package__’ is expected to
     be the same as *note __spec__.parent: 2d8.  *note __package__: 2d7.
     is now only used as a fallback during import resolution if
     ‘__spec__.parent’ is not defined.

     Changed in version 3.10: *note ImportWarning: 4fd. is raised if an
     import resolution falls back to ‘__package__’ instead of *note
     __spec__.parent: 2d8.

     Changed in version 3.12: Raise *note DeprecationWarning: 1a5.
     instead of *note ImportWarning: 4fd. when falling back to
     ‘__package__’ during import resolution.

     Deprecated since version 3.13, will be removed in version 3.15:
     ‘__package__’ will cease to be set or taken into consideration by
     the import system or standard library.

 -- Attribute: module.__loader__

     The *note loader: 17c1. object that the import machinery used to
     load the module.

     This attribute is mostly useful for introspection, but can be used
     for additional loader-specific functionality, for example getting
     data associated with a loader.

     ‘__loader__’ defaults to ‘None’ for modules created dynamically
     using the *note types.ModuleType: e45. constructor; use *note
     importlib.util.module_from_spec(): e44. instead to ensure the
     attribute is set to a *note loader: 17c1. object.

     It is 'strongly' recommended that you use *note
     module.__spec__.loader: 2e3. instead of ‘module.__loader__’.

     Changed in version 3.4: This attribute now defaults to ‘None’ for
     modules created dynamically using the *note types.ModuleType: e45.
     constructor.  Previously the attribute was optional.

     Deprecated since version 3.12, will be removed in version 3.16:
     Setting ‘__loader__’ on a module while failing to set
     ‘__spec__.loader’ is deprecated.  In Python 3.16, ‘__loader__’ will
     cease to be set or taken into consideration by the import system or
     the standard library.

 -- Attribute: module.__path__

     A (possibly empty) *note sequence: 4f4. of strings enumerating the
     locations where the package’s submodules will be found.
     Non-package modules should not have a ‘__path__’ attribute.  See
     *note __path__ attributes on modules: 20ca. for more details.

     It is 'strongly' recommended that you use *note
     module.__spec__.submodule_search_locations: 20cb. instead of
     ‘module.__path__’.

 -- Attribute: module.__file__

 -- Attribute: module.__cached__

     ‘__file__’ and ‘__cached__’ are both optional attributes that may
     or may not be set.  Both attributes should be a *note str: 44f.
     when they are available.

     ‘__file__’ indicates the pathname of the file from which the module
     was loaded (if loaded from a file), or the pathname of the shared
     library file for extension modules loaded dynamically from a shared
     library.  It might be missing for certain types of modules, such as
     C modules that are statically linked into the interpreter, and the
     *note import system: 20c2. may opt to leave it unset if it has no
     semantic meaning (for example, a module loaded from a database).

     If ‘__file__’ is set then the ‘__cached__’ attribute might also be
     set, which is the path to any compiled version of the code (for
     example, a byte-compiled file).  The file does not need to exist to
     set this attribute; the path can simply point to where the compiled
     file 'would' exist (see PEP 3147(2)).

     Note that ‘__cached__’ may be set even if ‘__file__’ is not set.
     However, that scenario is quite atypical.  Ultimately, the *note
     loader: 17c1. is what makes use of the module spec provided by the
     *note finder: 20cd. (from which ‘__file__’ and ‘__cached__’ are
     derived).  So if a loader can load from a cached module but
     otherwise does not load from a file, that atypical scenario may be
     appropriate.

     It is 'strongly' recommended that you use *note
     module.__spec__.cached: 2d6. instead of ‘module.__cached__’.

     Deprecated since version 3.13, will be removed in version 3.15:
     Setting ‘__cached__’ on a module while failing to set
     ‘__spec__.cached’ is deprecated.  In Python 3.15, ‘__cached__’ will
     cease to be set or taken into consideration by the import system or
     standard library.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0366/

   (2) https://peps.python.org/pep-3147/


File: python.info,  Node: Other writable attributes on module objects,  Next: Module dictionaries,  Prev: Import-related attributes on module objects,  Up: Modules<3>

4.3.2.28 Other writable attributes on module objects
....................................................

As well as the import-related attributes listed above, module objects
also have the following writable attributes:

 -- Attribute: module.__doc__

     The module’s documentation string, or ‘None’ if unavailable.  See
     also: *note __doc__ attributes: 931.

 -- Attribute: module.__annotations__

     A dictionary containing *note variable annotations: d7f. collected
     during module body execution.  For best practices on working with
     *note __annotations__: 20cf, please see *note Annotations Best
     Practices: 7dd.


File: python.info,  Node: Module dictionaries,  Prev: Other writable attributes on module objects,  Up: Modules<3>

4.3.2.29 Module dictionaries
............................

Module objects also have the following special read-only attribute:

 -- Attribute: module.__dict__

     The module’s namespace as a dictionary object.  Uniquely among the
     attributes listed here, ‘__dict__’ cannot be accessed as a global
     variable from within a module; it can only be accessed as an
     attribute on module objects.

     'CPython implementation detail:' Because of the way CPython clears
     module dictionaries, the module dictionary will be cleared when the
     module falls out of scope even if the dictionary still has live
     references.  To avoid this, copy the dictionary or keep the module
     around while using its dictionary directly.


File: python.info,  Node: Custom classes,  Next: Class instances,  Prev: Modules<3>,  Up: The standard type hierarchy

4.3.2.30 Custom classes
.......................

Custom class types are typically created by class definitions (see
section *note Class definitions: 131f.).  A class has a namespace
implemented by a dictionary object.  Class attribute references are
translated to lookups in this dictionary, e.g., ‘C.x’ is translated to
‘C.__dict__["x"]’ (although there are a number of hooks which allow for
other means of locating attributes).  When the attribute name is not
found there, the attribute search continues in the base classes.  This
search of the base classes uses the C3 method resolution order which
behaves correctly even in the presence of ‘diamond’ inheritance
structures where there are multiple inheritance paths leading back to a
common ancestor.  Additional details on the C3 MRO used by Python can be
found at *note The Python 2.3 Method Resolution Order: 14f9.

When a class attribute reference (for class ‘C’, say) would yield a
class method object, it is transformed into an instance method object
whose *note __self__: 1415. attribute is ‘C’.  When it would yield a
*note staticmethod: 419. object, it is transformed into the object
wrapped by the static method object.  See section *note Implementing
Descriptors: c70. for another way in which attributes retrieved from a
class may differ from those actually contained in its *note __dict__:
55e.

Class attribute assignments update the class’s dictionary, never the
dictionary of a base class.

A class object can be called (see above) to yield a class instance (see
below).

* Menu:

* Special attributes::
* Special methods::


File: python.info,  Node: Special attributes,  Next: Special methods,  Up: Custom classes

4.3.2.31 Special attributes
...........................

Attribute                                              Meaning
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- Attribute: type.__name__                           The class’s name.  See also:
                                                       *note __name__ attributes: 10a4.
                                                       
                                                       
 -- Attribute: type.__qualname__                       The class’s *note qualified name: 1acb.  See also:
                                                       *note __qualname__ attributes: 10a3.
                                                       
                                                       
 -- Attribute: type.__module__                         The name of the module in which the class was
                                                       defined.
                                                       
                                                       
 -- Attribute: type.__dict__                           A *note mapping proxy: 470. providing a read-only
                                                       view of the class’s namespace.  See also:
                                                       *note __dict__ attributes: 55e.
                                                       
                                                       
 -- Attribute: type.__bases__                          A *note tuple: 373. containing the class’s bases.
                                                       In most cases, for a class defined as ‘class X(A, B,
                                                       C)’, ‘X.__bases__’ will be exactly equal to ‘(A, B,
                                                       C)’.
                                                       
                                                       
 -- Attribute: type.__base__                           'CPython implementation detail:' The single base
                                                       class in the inheritance chain that is responsible
                                                       for the memory layout of instances.  This attribute
                                                       corresponds to *note tp_base: 20d7. at the C level.
                                                       
                                                       
 -- Attribute: type.__doc__                            The class’s documentation string, or ‘None’ if
                                                       undefined.  Not inherited by subclasses.
                                                       
                                                       
 -- Attribute: type.__annotations__                    A dictionary containing
                                                       *note variable annotations: d7f. collected during
                                                       class body execution.  For best practices on working
                                                       with ‘__annotations__’, please see
                                                       *note Annotations Best Practices: 7dd.
                                                       
                                                            Caution: Accessing the ‘__annotations__’
                                                            attribute of a class object directly may yield
                                                            incorrect results in the presence of
                                                            metaclasses.  In addition, the attribute may
                                                            not exist for some classes.  Use
                                                            *note inspect.get_annotations(): 819. to
                                                            retrieve class annotations safely.
                                                       
                                                       
 -- Attribute: type.__type_params__                    A *note tuple: 373. containing the
                                                       *note type parameters: 2b3. of a
                                                       *note generic class: 455.
                                                       
                                                       Added in version 3.12.
                                                       
                                                       
 -- Attribute: type.__static_attributes__              A *note tuple: 373. containing names of attributes
                                                       of this class which are assigned through ‘self.X’
                                                       from any function in its body.
                                                       
                                                       Added in version 3.13.
                                                       
                                                       
 -- Attribute: type.__firstlineno__                    The line number of the first line of the class
                                                       definition, including decorators.  Setting the
                                                       *note __module__: 377. attribute removes the
                                                       ‘__firstlineno__’ item from the type’s dictionary.
                                                       
                                                       Added in version 3.13.
                                                       
                                                       
 -- Attribute: type.__mro__                            The *note tuple: 373. of classes that are considered
                                                       when looking for base classes during method
                                                       resolution.
                                                       


File: python.info,  Node: Special methods,  Prev: Special attributes,  Up: Custom classes

4.3.2.32 Special methods
........................

In addition to the special attributes described above, all Python
classes also have the following two methods available:

 -- Method: type.mro ()

     This method can be overridden by a metaclass to customize the
     method resolution order for its instances.  It is called at class
     instantiation, and its result is stored in *note __mro__: 20da.

 -- Method: type.__subclasses__ ()

     Each class keeps a list of weak references to its immediate
     subclasses.  This method returns a list of all those references
     still alive.  The list is in definition order.  Example:

          >>> class A: pass
          >>> class B(A): pass
          >>> A.__subclasses__()
          [<class 'B'>]


File: python.info,  Node: Class instances,  Next: I/O objects also known as file objects,  Prev: Custom classes,  Up: The standard type hierarchy

4.3.2.33 Class instances
........................

A class instance is created by calling a class object (see above).  A
class instance has a namespace implemented as a dictionary which is the
first place in which attribute references are searched.  When an
attribute is not found there, and the instance’s class has an attribute
by that name, the search continues with the class attributes.  If a
class attribute is found that is a user-defined function object, it is
transformed into an instance method object whose *note __self__: 1415.
attribute is the instance.  Static method and class method objects are
also transformed; see above under “Classes”.  See section *note
Implementing Descriptors: c70. for another way in which attributes of a
class retrieved via its instances may differ from the objects actually
stored in the class’s *note __dict__: 55e.  If no class attribute is
found, and the object’s class has a *note __getattr__(): 4d6. method,
that is called to satisfy the lookup.

Attribute assignments and deletions update the instance’s dictionary,
never a class’s dictionary.  If the class has a *note __setattr__():
20de. or *note __delattr__(): 20df. method, this is called instead of
updating the instance dictionary directly.

Class instances can pretend to be numbers, sequences, or mappings if
they have methods with certain special names.  See section *note Special
method names: c8f.

* Menu:

* Special attributes: Special attributes<2>.


File: python.info,  Node: Special attributes<2>,  Up: Class instances

4.3.2.34 Special attributes
...........................

 -- Attribute: object.__class__

     The class to which a class instance belongs.

 -- Attribute: object.__dict__

     A dictionary or other mapping object used to store an object’s
     (writable) attributes.  Not all instances have a ‘__dict__’
     attribute; see the section on *note __slots__: 20e1. for more
     details.


File: python.info,  Node: I/O objects also known as file objects,  Next: Internal types,  Prev: Class instances,  Up: The standard type hierarchy

4.3.2.35 I/O objects (also known as file objects)
.................................................

A *note file object: 1208. represents an open file.  Various shortcuts
are available to create file objects: the *note open(): 51f. built-in
function, and also *note os.popen(): a96, *note os.fdopen(): 20e3, and
the *note makefile(): 11e3. method of socket objects (and perhaps by
other functions or methods provided by extension modules).

File objects implement common methods, listed below, to simplify usage
in generic code.  They are expected to be *note With Statement Context
Managers: 20e4.

The objects ‘sys.stdin’, ‘sys.stdout’ and ‘sys.stderr’ are initialized
to file objects corresponding to the interpreter’s standard input,
output and error streams; they are all open in text mode and therefore
follow the interface defined by the *note io.TextIOBase: 698. abstract
class.

 -- Method: file.read (size=-1, /)

     Retrieve up to 'size' data from the file.  As a convenience if
     'size' is unspecified or -1 retrieve all data available.

 -- Method: file.write (data, /)

     Store 'data' to the file.

 -- Method: file.close ()

     Flush any buffers and close the underlying file.


File: python.info,  Node: Internal types,  Prev: I/O objects also known as file objects,  Up: The standard type hierarchy

4.3.2.36 Internal types
.......................

A few types used internally by the interpreter are exposed to the user.
Their definitions may change with future versions of the interpreter,
but they are mentioned here for completeness.

* Menu:

* Code objects::
* Frame objects::
* Traceback objects::
* Slice objects::
* Static method objects::
* Class method objects::


File: python.info,  Node: Code objects,  Next: Frame objects,  Up: Internal types

4.3.2.37 Code objects
.....................

Code objects represent 'byte-compiled' executable Python code, or *note
bytecode: 187.  The difference between a code object and a function
object is that the function object contains an explicit reference to the
function’s globals (the module in which it was defined), while a code
object contains no context; also the default argument values are stored
in the function object, not in the code object (because they represent
values calculated at run-time).  Unlike function objects, code objects
are immutable and contain no references (directly or indirectly) to
mutable objects.

* Menu:

* Special read-only attributes: Special read-only attributes<2>.
* Methods on code objects::


File: python.info,  Node: Special read-only attributes<2>,  Next: Methods on code objects,  Up: Code objects

4.3.2.38 Special read-only attributes
.....................................

 -- Attribute: codeobject.co_name                      The function name
                                                       
                                                       
 -- Attribute: codeobject.co_qualname                  The fully qualified function name
                                                       
                                                       Added in version 3.11.
                                                       
                                                       
 -- Attribute: codeobject.co_argcount                  The total number of positional
                                                       *note parameters: 20ae. (including positional-only
                                                       parameters and parameters with default values) that
                                                       the function has
                                                       
                                                       
 -- Attribute: codeobject.co_posonlyargcount           The number of positional-only
                                                       *note parameters: 20ae. (including arguments with
                                                       default values) that the function has
                                                       
                                                       
 -- Attribute: codeobject.co_kwonlyargcount            The number of keyword-only *note parameters: 20ae.
                                                       (including arguments with default values) that the
                                                       function has
                                                       
                                                       
 -- Attribute: codeobject.co_nlocals                   The number of *note local variables: 20a9. used by
                                                       the function (including parameters)
                                                       
                                                       
 -- Attribute: codeobject.co_varnames                  A *note tuple: 373. containing the names of the
                                                       local variables in the function (starting with the
                                                       parameter names)
                                                       
                                                       
 -- Attribute: codeobject.co_cellvars                  A *note tuple: 373. containing the names of
                                                       *note local variables: 20a9. that are referenced
                                                       from at least one *note nested scope: 20f3. inside
                                                       the function
                                                       
                                                       
 -- Attribute: codeobject.co_freevars                  A *note tuple: 373. containing the names of
                                                       *note free (closure) variables: 20f4. that a
                                                       *note nested scope: 20f3. references in an outer
                                                       scope.  See also *note function.__closure__: 1318.
                                                       
                                                       Note: references to global and builtin names are
                                                       'not' included.
                                                       
                                                       
 -- Attribute: codeobject.co_code                      A string representing the sequence of
                                                       *note bytecode: 187. instructions in the function
                                                       
                                                       
 -- Attribute: codeobject.co_consts                    A *note tuple: 373. containing the literals used by
                                                       the *note bytecode: 187. in the function
                                                       
                                                       
 -- Attribute: codeobject.co_names                     A *note tuple: 373. containing the names used by the
                                                       *note bytecode: 187. in the function
                                                       
                                                       
 -- Attribute: codeobject.co_filename                  The name of the file from which the code was
                                                       compiled
                                                       
                                                       
 -- Attribute: codeobject.co_firstlineno               The line number of the first line of the function
                                                       
                                                       
 -- Attribute: codeobject.co_lnotab                    A string encoding the mapping from
                                                       *note bytecode: 187. offsets to line numbers.  For
                                                       details, see the source code of the interpreter.
                                                       
                                                       Deprecated since version 3.12: This attribute of
                                                       code objects is deprecated, and may be removed in
                                                       Python 3.15.
                                                       
                                                       
 -- Attribute: codeobject.co_stacksize                 The required stack size of the code object
                                                       
                                                       
 -- Attribute: codeobject.co_flags                     An *note integer: 257. encoding a number of flags
                                                       for the interpreter.
                                                       

The following flag bits are defined for *note co_flags: 20f9.: bit
‘0x04’ is set if the function uses the ‘*arguments’ syntax to accept an
arbitrary number of positional arguments; bit ‘0x08’ is set if the
function uses the ‘**keywords’ syntax to accept arbitrary keyword
arguments; bit ‘0x20’ is set if the function is a generator.  See *note
Code Objects Bit Flags: 20fa. for details on the semantics of each flags
that might be present.

Future feature declarations (for example, ‘from __future__ import
division’) also use bits in *note co_flags: 20f9. to indicate whether a
code object was compiled with a particular feature enabled.  See *note
compiler_flag: 20fb.

Other bits in *note co_flags: 20f9. are reserved for internal use.

If a code object represents a function, the first item in *note
co_consts: 1679. is the documentation string of the function, or ‘None’
if undefined.


File: python.info,  Node: Methods on code objects,  Prev: Special read-only attributes<2>,  Up: Code objects

4.3.2.39 Methods on code objects
................................

 -- Method: codeobject.co_positions ()

     Returns an iterable over the source code positions of each *note
     bytecode: 187. instruction in the code object.

     The iterator returns *note tuple: 373.s containing the
     ‘(start_line, end_line, start_column, end_column)’.  The 'i-th'
     tuple corresponds to the position of the source code that compiled
     to the 'i-th' code unit.  Column information is 0-indexed utf-8
     byte offsets on the given source line.

     This positional information can be missing.  A non-exhaustive lists
     of cases where this may happen:

        - Running the interpreter with *note -X: 176. ‘no_debug_ranges’.

        - Loading a pyc file compiled while using *note -X: 176.
          ‘no_debug_ranges’.

        - Position tuples corresponding to artificial instructions.

        - Line and column numbers that can’t be represented due to
          implementation specific limitations.

     When this occurs, some or all of the tuple elements can be *note
     None: 678.

     Added in version 3.11.

          Note: This feature requires storing column positions in code
          objects which may result in a small increase of disk usage of
          compiled Python files or interpreter memory usage.  To avoid
          storing the extra information and/or deactivate printing the
          extra traceback information, the *note -X: 176.
          ‘no_debug_ranges’ command line flag or the *note
          PYTHONNODEBUGRANGES: 5b9. environment variable can be used.

 -- Method: codeobject.co_lines ()

     Returns an iterator that yields information about successive ranges
     of *note bytecode: 187.s.  Each item yielded is a ‘(start, end,
     lineno)’ *note tuple: 373.:

        * ‘start’ (an *note int: 257.) represents the offset (inclusive)
          of the start of the *note bytecode: 187. range

        * ‘end’ (an *note int: 257.) represents the offset (exclusive)
          of the end of the *note bytecode: 187. range

        * ‘lineno’ is an *note int: 257. representing the line number of
          the *note bytecode: 187. range, or ‘None’ if the bytecodes in
          the given range have no line number

     The items yielded will have the following properties:

        * The first range yielded will have a ‘start’ of 0.

        * The ‘(start, end)’ ranges will be non-decreasing and
          consecutive.  That is, for any pair of *note tuple: 373.s, the
          ‘start’ of the second will be equal to the ‘end’ of the first.

        * No range will be backwards: ‘end >= start’ for all triples.

        * The last *note tuple: 373. yielded will have ‘end’ equal to
          the size of the *note bytecode: 187.

     Zero-width ranges, where ‘start == end’, are allowed.  Zero-width
     ranges are used for lines that are present in the source code, but
     have been eliminated by the *note bytecode: 187. compiler.

     Added in version 3.10.

     See also
     ........

     PEP 626(1) - Precise line numbers for debugging and other tools.

          The PEP that introduced the ‘co_lines()’ method.

 -- Method: codeobject.replace (**kwargs)

     Return a copy of the code object with new values for the specified
     fields.

     Code objects are also supported by the generic function *note
     copy.replace(): 151.

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0626/


File: python.info,  Node: Frame objects,  Next: Traceback objects,  Prev: Code objects,  Up: Internal types

4.3.2.40 Frame objects
......................

Frame objects represent execution frames.  They may occur in *note
traceback objects: b0d, and are also passed to registered trace
functions.

* Menu:

* Special read-only attributes: Special read-only attributes<3>.
* Special writable attributes: Special writable attributes<2>.
* Frame object methods::


File: python.info,  Node: Special read-only attributes<3>,  Next: Special writable attributes<2>,  Up: Frame objects

4.3.2.41 Special read-only attributes
.....................................

 -- Attribute: frame.f_back                            Points to the previous stack frame (towards the
                                                       caller), or ‘None’ if this is the bottom stack frame
                                                       
                                                       
 -- Attribute: frame.f_code                            The *note code object: 1d2. being executed in this
                                                       frame.  Accessing this attribute raises an
                                                       *note auditing event: 1a15. ‘object.__getattr__’
                                                       with arguments ‘obj’ and ‘"f_code"’.
                                                       
                                                       
 -- Attribute: frame.f_locals                          The mapping used by the frame to look up
                                                       *note local variables: 20a9.  If the frame refers to
                                                       an *note optimized scope: 17e, this may return a
                                                       write-through proxy object.
                                                       
                                                       Changed in version 3.13: Return a proxy for
                                                       optimized scopes.
                                                       
                                                       
 -- Attribute: frame.f_globals                         The dictionary used by the frame to look up
                                                       *note global variables: 20a9.
                                                       
                                                       
 -- Attribute: frame.f_builtins                        The dictionary used by the frame to look up
                                                       *note built-in (intrinsic) names: 20a9.
                                                       
                                                       
 -- Attribute: frame.f_lasti                           The “precise instruction” of the frame object (this
                                                       is an index into the *note bytecode: 187. string of
                                                       the *note code object: 1d2.)
                                                       


File: python.info,  Node: Special writable attributes<2>,  Next: Frame object methods,  Prev: Special read-only attributes<3>,  Up: Frame objects

4.3.2.42 Special writable attributes
....................................

 -- Attribute: frame.f_trace                           If not ‘None’, this is a function called for various
                                                       events during code execution (this is used by
                                                       debuggers).  Normally an event is triggered for each
                                                       new source line (see *note f_trace_lines: bfc.).
                                                       
                                                       
 -- Attribute: frame.f_trace_lines                     Set this attribute to *note False: b4f. to disable
                                                       triggering a tracing event for each source line.
                                                       
                                                       
 -- Attribute: frame.f_trace_opcodes                   Set this attribute to *note True: c2d. to allow
                                                       per-opcode events to be requested.  Note that this
                                                       may lead to undefined interpreter behaviour if
                                                       exceptions raised by the trace function escape to
                                                       the function being traced.
                                                       
                                                       
 -- Attribute: frame.f_lineno                          The current line number of the frame – writing to
                                                       this from within a trace function jumps to the given
                                                       line (only for the bottom-most frame).  A debugger
                                                       can implement a Jump command (aka Set Next
                                                       Statement) by writing to this attribute.
                                                       


File: python.info,  Node: Frame object methods,  Prev: Special writable attributes<2>,  Up: Frame objects

4.3.2.43 Frame object methods
.............................

Frame objects support one method:

 -- Method: frame.clear ()

     This method clears all references to *note local variables: 20a9.
     held by the frame.  Also, if the frame belonged to a *note
     generator: 109f, the generator is finalized.  This helps break
     reference cycles involving frame objects (for example when catching
     an *note exception: 19cc. and storing its *note traceback: b0d. for
     later use).

     *note RuntimeError: 195. is raised if the frame is currently
     executing or suspended.

     Added in version 3.4.

     Changed in version 3.13: Attempting to clear a suspended frame
     raises *note RuntimeError: 195. (as has always been the case for
     executing frames).


File: python.info,  Node: Traceback objects,  Next: Slice objects,  Prev: Frame objects,  Up: Internal types

4.3.2.44 Traceback objects
..........................

Traceback objects represent the stack trace of an *note exception: 1e2a.
A traceback object is implicitly created when an exception occurs, and
may also be explicitly created by calling *note types.TracebackType:
b0b.

Changed in version 3.7: Traceback objects can now be explicitly
instantiated from Python code.

For implicitly created tracebacks, when the search for an exception
handler unwinds the execution stack, at each unwound level a traceback
object is inserted in front of the current traceback.  When an exception
handler is entered, the stack trace is made available to the program.
(See section *note The try statement: 6ec.)  It is accessible as the
third item of the tuple returned by *note sys.exc_info(): 68d, and as
the *note __traceback__: 130e. attribute of the caught exception.

When the program contains no suitable handler, the stack trace is
written (nicely formatted) to the standard error stream; if the
interpreter is interactive, it is also made available to the user as
*note sys.last_traceback: 4c4.

For explicitly created tracebacks, it is up to the creator of the
traceback to determine how the *note tb_next: b0c. attributes should be
linked to form a full stack trace.

Special read-only attributes:

 -- Attribute: traceback.tb_frame                      Points to the execution *note frame: 6e3. of the
                                                       current level.
                                                       
                                                       Accessing this attribute raises an
                                                       *note auditing event: 1a15. ‘object.__getattr__’
                                                       with arguments ‘obj’ and ‘"tb_frame"’.
                                                       
                                                       
 -- Attribute: traceback.tb_lineno                     Gives the line number where the exception occurred
                                                       
                                                       
 -- Attribute: traceback.tb_lasti                      Indicates the “precise instruction”.
                                                       

The line number and last instruction in the traceback may differ from
the line number of its *note frame object: 6e3. if the exception
occurred in a *note try: 6ec. statement with no matching except clause
or with a *note finally: 9d5. clause.

 -- Attribute: traceback.tb_next

     The special writable attribute ‘tb_next’ is the next level in the
     stack trace (towards the frame where the exception occurred), or
     ‘None’ if there is no next level.

     Changed in version 3.7: This attribute is now writable


File: python.info,  Node: Slice objects,  Next: Static method objects,  Prev: Traceback objects,  Up: Internal types

4.3.2.45 Slice objects
......................

Slice objects are used to represent slices for *note __getitem__(): 283.
methods.  They are also created by the built-in *note slice(): 46c.
function.

Special read-only attributes: *note start: 210b. is the lower bound;
*note stop: 210c. is the upper bound; *note step: 210d. is the step
value; each is ‘None’ if omitted.  These attributes can have any type.

Slice objects support one method:

 -- Method: slice.indices (self, length)

     This method takes a single integer argument 'length' and computes
     information about the slice that the slice object would describe if
     applied to a sequence of 'length' items.  It returns a tuple of
     three integers; respectively these are the 'start' and 'stop'
     indices and the 'step' or stride length of the slice.  Missing or
     out-of-bounds indices are handled in a manner consistent with
     regular slices.


File: python.info,  Node: Static method objects,  Next: Class method objects,  Prev: Slice objects,  Up: Internal types

4.3.2.46 Static method objects
..............................

Static method objects provide a way of defeating the transformation of
function objects to method objects described above.  A static method
object is a wrapper around any other object, usually a user-defined
method object.  When a static method object is retrieved from a class or
a class instance, the object actually returned is the wrapped object,
which is not subject to any further transformation.  Static method
objects are also callable.  Static method objects are created by the
built-in *note staticmethod(): 419. constructor.


File: python.info,  Node: Class method objects,  Prev: Static method objects,  Up: Internal types

4.3.2.47 Class method objects
.............................

A class method object, like a static method object, is a wrapper around
another object that alters the way in which that object is retrieved
from classes and class instances.  The behaviour of class method objects
upon such retrieval is described above, under *note “instance methods”:
1e5f.  Class method objects are created by the built-in *note
classmethod(): 166. constructor.


File: python.info,  Node: Special method names,  Next: Coroutines,  Prev: The standard type hierarchy,  Up: Data model

4.3.3 Special method names
--------------------------

A class can implement certain operations that are invoked by special
syntax (such as arithmetic operations or subscripting and slicing) by
defining methods with special names.  This is Python’s approach to
'operator overloading', allowing classes to define their own behavior
with respect to language operators.  For instance, if a class defines a
method named *note __getitem__(): 283, and ‘x’ is an instance of this
class, then ‘x[i]’ is roughly equivalent to ‘type(x).__getitem__(x, i)’.
Except where mentioned, attempts to execute an operation raise an
exception when no appropriate method is defined (typically *note
AttributeError: 34e. or *note TypeError: 2c3.).

Setting a special method to ‘None’ indicates that the corresponding
operation is not available.  For example, if a class sets *note
__iter__(): c90. to ‘None’, the class is not iterable, so calling *note
iter(): 7db. on its instances will raise a *note TypeError: 2c3.
(without falling back to *note __getitem__(): 283.).  (1)

When implementing a class that emulates any built-in type, it is
important that the emulation only be implemented to the degree that it
makes sense for the object being modelled.  For example, some sequences
may work well with retrieval of individual elements, but extracting a
slice may not make sense.  (One example of this is the *note NodeList:
2111. interface in the W3C’s Document Object Model.)

* Menu:

* Basic customization::
* Customizing attribute access::
* Customizing class creation::
* Customizing instance and subclass checks::
* Emulating generic types::
* Emulating callable objects::
* Emulating container types::
* Emulating numeric types::
* With Statement Context Managers::
* Customizing positional arguments in class pattern matching::
* Emulating buffer types::
* Special method lookup::

   ---------- Footnotes ----------

   (1) The *note __hash__(): b14, *note __iter__(): c90, *note
__reversed__(): cad, *note __contains__(): 1406, *note
__class_getitem__(): 73e. and *note __fspath__(): c73. methods have
special handling for this.  Others will still raise a *note TypeError:
2c3, but may do so by relying on the behavior that ‘None’ is not
callable.


File: python.info,  Node: Basic customization,  Next: Customizing attribute access,  Up: Special method names

4.3.3.1 Basic customization
...........................

 -- Method: object.__new__ (cls[, ...])

     Called to create a new instance of class 'cls'.  ‘__new__()’ is a
     static method (special-cased so you need not declare it as such)
     that takes the class of which an instance was requested as its
     first argument.  The remaining arguments are those passed to the
     object constructor expression (the call to the class).  The return
     value of ‘__new__()’ should be the new object instance (usually an
     instance of 'cls').

     Typical implementations create a new instance of the class by
     invoking the superclass’s ‘__new__()’ method using
     ‘super().__new__(cls[, ...])’ with appropriate arguments and then
     modifying the newly created instance as necessary before returning
     it.

     If ‘__new__()’ is invoked during object construction and it returns
     an instance of 'cls', then the new instance’s *note __init__():
     6b3. method will be invoked like ‘__init__(self[, ...])’, where
     'self' is the new instance and the remaining arguments are the same
     as were passed to the object constructor.

     If ‘__new__()’ does not return an instance of 'cls', then the new
     instance’s *note __init__(): 6b3. method will not be invoked.

     ‘__new__()’ is intended mainly to allow subclasses of immutable
     types (like int, str, or tuple) to customize instance creation.  It
     is also commonly overridden in custom metaclasses in order to
     customize class creation.

 -- Method: object.__init__ (self[, ...])

     Called after the instance has been created (by *note __new__():
     583.), but before it is returned to the caller.  The arguments are
     those passed to the class constructor expression.  If a base class
     has an ‘__init__()’ method, the derived class’s ‘__init__()’
     method, if any, must explicitly call it to ensure proper
     initialization of the base class part of the instance; for example:
     ‘super().__init__([args...])’.

     Because *note __new__(): 583. and ‘__init__()’ work together in
     constructing objects (‘__new__()’ to create it, and ‘__init__()’ to
     customize it), no non-‘None’ value may be returned by ‘__init__()’;
     doing so will cause a *note TypeError: 2c3. to be raised at
     runtime.

 -- Method: object.__del__ (self)

     Called when the instance is about to be destroyed.  This is also
     called a finalizer or (improperly) a destructor.  If a base class
     has a ‘__del__()’ method, the derived class’s ‘__del__()’ method,
     if any, must explicitly call it to ensure proper deletion of the
     base class part of the instance.

     It is possible (though not recommended!)  for the ‘__del__()’
     method to postpone destruction of the instance by creating a new
     reference to it.  This is called object 'resurrection'.  It is
     implementation-dependent whether ‘__del__()’ is called a second
     time when a resurrected object is about to be destroyed; the
     current *note CPython: 6f9. implementation only calls it once.

     It is not guaranteed that ‘__del__()’ methods are called for
     objects that still exist when the interpreter exits.  *note
     weakref.finalize: a8b. provides a straightforward way to register a
     cleanup function to be called when an object is garbage collected.

          Note: ‘del x’ doesn’t directly call ‘x.__del__()’ — the former
          decrements the reference count for ‘x’ by one, and the latter
          is only called when ‘x’’s reference count reaches zero.

     'CPython implementation detail:' It is possible for a reference
     cycle to prevent the reference count of an object from going to
     zero.  In this case, the cycle will be later detected and deleted
     by the *note cyclic garbage collector: 1a83.  A common cause of
     reference cycles is when an exception has been caught in a local
     variable.  The frame’s locals then reference the exception, which
     references its own traceback, which references the locals of all
     frames caught in the traceback.

     See also
     ........

     Documentation for the *note gc: 60. module.

          Warning: Due to the precarious circumstances under which
          ‘__del__()’ methods are invoked, exceptions that occur during
          their execution are ignored, and a warning is printed to
          ‘sys.stderr’ instead.  In particular:

             * ‘__del__()’ can be invoked when arbitrary code is being
               executed, including from any arbitrary thread.  If
               ‘__del__()’ needs to take a lock or invoke any other
               blocking resource, it may deadlock as the resource may
               already be taken by the code that gets interrupted to
               execute ‘__del__()’.

             * ‘__del__()’ can be executed during interpreter shutdown.
               As a consequence, the global variables it needs to access
               (including other modules) may already have been deleted
               or set to ‘None’.  Python guarantees that globals whose
               name begins with a single underscore are deleted from
               their module before other globals are deleted; if no
               other references to such globals exist, this may help in
               assuring that imported modules are still available at the
               time when the ‘__del__()’ method is called.

 -- Method: object.__repr__ (self)

     Called by the *note repr(): 803. built-in function to compute the
     “official” string representation of an object.  If at all possible,
     this should look like a valid Python expression that could be used
     to recreate an object with the same value (given an appropriate
     environment).  If this is not possible, a string of the form
     ‘<...some useful description...>’ should be returned.  The return
     value must be a string object.  If a class defines ‘__repr__()’ but
     not *note __str__(): 620, then ‘__repr__()’ is also used when an
     “informal” string representation of instances of that class is
     required.

     This is typically used for debugging, so it is important that the
     representation is information-rich and unambiguous.  A default
     implementation is provided by the *note object: a9b. class itself.

 -- Method: object.__str__ (self)

     Called by *note str(object): 44f, the default *note __format__():
     621. implementation, and the built-in function *note print(): fae,
     to compute the “informal” or nicely printable string representation
     of an object.  The return value must be a *note str: 1d92. object.

     This method differs from *note object.__repr__(): 61f. in that
     there is no expectation that ‘__str__()’ return a valid Python
     expression: a more convenient or concise representation can be
     used.

     The default implementation defined by the built-in type *note
     object: a9b. calls *note object.__repr__(): 61f.

 -- Method: object.__bytes__ (self)

     Called by *note bytes: 1c4b. to compute a byte-string
     representation of an object.  This should return a *note bytes:
     1c2. object.  The *note object: a9b. class itself does not provide
     this method.

 -- Method: object.__format__ (self, format_spec)

     Called by the *note format(): 622. built-in function, and by
     extension, evaluation of *note formatted string literals: 9b4. and
     the *note str.format(): 624. method, to produce a “formatted”
     string representation of an object.  The 'format_spec' argument is
     a string that contains a description of the formatting options
     desired.  The interpretation of the 'format_spec' argument is up to
     the type implementing ‘__format__()’, however most classes will
     either delegate formatting to one of the built-in types, or use a
     similar formatting option syntax.

     See *note Format specification mini-language: 1e8. for a
     description of the standard formatting syntax.

     The return value must be a string object.

     The default implementation by the *note object: a9b. class should
     be given an empty 'format_spec' string.  It delegates to *note
     __str__(): 620.

     Changed in version 3.4: The __format__ method of ‘object’ itself
     raises a *note TypeError: 2c3. if passed any non-empty string.

     Changed in version 3.7: ‘object.__format__(x, '')’ is now
     equivalent to ‘str(x)’ rather than ‘format(str(x), '')’.

 -- Method: object.__lt__ (self, other)
 -- Method: object.__le__ (self, other)
 -- Method: object.__eq__ (self, other)
 -- Method: object.__ne__ (self, other)
 -- Method: object.__gt__ (self, other)
 -- Method: object.__ge__ (self, other)

     These are the so-called “rich comparison” methods.  The
     correspondence between operator symbols and method names is as
     follows: ‘x<y’ calls ‘x.__lt__(y)’, ‘x<=y’ calls ‘x.__le__(y)’,
     ‘x==y’ calls ‘x.__eq__(y)’, ‘x!=y’ calls ‘x.__ne__(y)’, ‘x>y’ calls
     ‘x.__gt__(y)’, and ‘x>=y’ calls ‘x.__ge__(y)’.

     A rich comparison method may return the singleton *note
     NotImplemented: 7d6. if it does not implement the operation for a
     given pair of arguments.  By convention, ‘False’ and ‘True’ are
     returned for a successful comparison.  However, these methods can
     return any value, so if the comparison operator is used in a
     Boolean context (e.g., in the condition of an ‘if’ statement),
     Python will call *note bool(): 46b. on the value to determine if
     the result is true or false.

     By default, ‘object’ implements ‘__eq__()’ by using ‘is’, returning
     *note NotImplemented: 7d6. in the case of a false comparison: ‘True
     if x is y else NotImplemented’.  For ‘__ne__()’, by default it
     delegates to ‘__eq__()’ and inverts the result unless it is
     ‘NotImplemented’.  There are no other implied relationships among
     the comparison operators or default implementations; for example,
     the truth of ‘(x<y or x==y)’ does not imply ‘x<=y’.  To
     automatically generate ordering operations from a single root
     operation, see *note functools.total_ordering(): f7a.

     By default, the *note object: a9b. class provides implementations
     consistent with *note Value comparisons: 19c4.: equality compares
     according to object identity, and order comparisons raise *note
     TypeError: 2c3.  Each default method may generate these results
     directly, but may also return *note NotImplemented: 7d6.

     See the paragraph on *note __hash__(): b14. for some important
     notes on creating *note hashable: 613. objects which support custom
     comparison operations and are usable as dictionary keys.

     There are no swapped-argument versions of these methods (to be used
     when the left argument does not support the operation but the right
     argument does); rather, ‘__lt__()’ and ‘__gt__()’ are each other’s
     reflection, ‘__le__()’ and ‘__ge__()’ are each other’s reflection,
     and ‘__eq__()’ and ‘__ne__()’ are their own reflection.  If the
     operands are of different types, and the right operand’s type is a
     direct or indirect subclass of the left operand’s type, the
     reflected method of the right operand has priority, otherwise the
     left operand’s method has priority.  Virtual subclassing is not
     considered.

     When no appropriate method returns any value other than *note
     NotImplemented: 7d6, the ‘==’ and ‘!=’ operators will fall back to
     ‘is’ and ‘is not’, respectively.

 -- Method: object.__hash__ (self)

     Called by built-in function *note hash(): 5ee. and for operations
     on members of hashed collections including *note set: 5dc, *note
     frozenset: 5dd, and *note dict: 256.  The ‘__hash__()’ method
     should return an integer.  The only required property is that
     objects which compare equal have the same hash value; it is advised
     to mix together the hash values of the components of the object
     that also play a part in comparison of objects by packing them into
     a tuple and hashing the tuple.  Example:

          def __hash__(self):
              return hash((self.name, self.nick, self.color))

          Note: *note hash(): 5ee. truncates the value returned from an
          object’s custom ‘__hash__()’ method to the size of a *note
          Py_ssize_t: a6e.  This is typically 8 bytes on 64-bit builds
          and 4 bytes on 32-bit builds.  If an object’s ‘__hash__()’
          must interoperate on builds of different bit sizes, be sure to
          check the width on all supported builds.  An easy way to do
          this is with ‘python -c "import sys;
          print(sys.hash_info.width)"’.

     If a class does not define an *note __eq__(): b13. method it should
     not define a ‘__hash__()’ operation either; if it defines
     ‘__eq__()’ but not ‘__hash__()’, its instances will not be usable
     as items in hashable collections.  If a class defines mutable
     objects and implements an ‘__eq__()’ method, it should not
     implement ‘__hash__()’, since the implementation of *note hashable:
     613. collections requires that a key’s hash value is immutable (if
     the object’s hash value changes, it will be in the wrong hash
     bucket).

     User-defined classes have *note __eq__(): b13. and ‘__hash__()’
     methods by default (inherited from the *note object: a9b. class);
     with them, all objects compare unequal (except with themselves) and
     ‘x.__hash__()’ returns an appropriate value such that ‘x == y’
     implies both that ‘x is y’ and ‘hash(x) == hash(y)’.

     A class that overrides *note __eq__(): b13. and does not define
     ‘__hash__()’ will have its ‘__hash__()’ implicitly set to ‘None’.
     When the ‘__hash__()’ method of a class is ‘None’, instances of the
     class will raise an appropriate *note TypeError: 2c3. when a
     program attempts to retrieve their hash value, and will also be
     correctly identified as unhashable when checking ‘isinstance(obj,
     collections.abc.Hashable)’.

     If a class that overrides *note __eq__(): b13. needs to retain the
     implementation of ‘__hash__()’ from a parent class, the interpreter
     must be told this explicitly by setting ‘__hash__ =
     <ParentClass>.__hash__’.

     If a class that does not override *note __eq__(): b13. wishes to
     suppress hash support, it should include ‘__hash__ = None’ in the
     class definition.  A class which defines its own ‘__hash__()’ that
     explicitly raises a *note TypeError: 2c3. would be incorrectly
     identified as hashable by an ‘isinstance(obj,
     collections.abc.Hashable)’ call.

          Note: By default, the ‘__hash__()’ values of str and bytes
          objects are “salted” with an unpredictable random value.
          Although they remain constant within an individual Python
          process, they are not predictable between repeated invocations
          of Python.

          This is intended to provide protection against a
          denial-of-service caused by carefully chosen inputs that
          exploit the worst case performance of a dict insertion,
          'O'('n'^2) complexity.  See
          ‘https://ocert.org/advisories/ocert-2011-003.html’ for
          details.

          Changing hash values affects the iteration order of sets.
          Python has never made guarantees about this ordering (and it
          typically varies between 32-bit and 64-bit builds).

          See also *note PYTHONHASHSEED: 10bb.

     Changed in version 3.3: Hash randomization is enabled by default.

 -- Method: object.__bool__ (self)

     Called to implement truth value testing and the built-in operation
     ‘bool()’; should return ‘False’ or ‘True’.  When this method is not
     defined, *note __len__(): 15da. is called, if it is defined, and
     the object is considered true if its result is nonzero.  If a class
     defines neither ‘__len__()’ nor ‘__bool__()’ (which is true of the
     *note object: a9b. class itself), all its instances are considered
     true.


File: python.info,  Node: Customizing attribute access,  Next: Customizing class creation,  Prev: Basic customization,  Up: Special method names

4.3.3.2 Customizing attribute access
....................................

The following methods can be defined to customize the meaning of
attribute access (use of, assignment to, or deletion of ‘x.name’) for
class instances.

 -- Method: object.__getattr__ (self, name)

     Called when the default attribute access fails with an *note
     AttributeError: 34e. (either *note __getattribute__(): bf1. raises
     an ‘AttributeError’ because 'name' is not an instance attribute or
     an attribute in the class tree for ‘self’; or *note __get__():
     1537. of a 'name' property raises ‘AttributeError’).  This method
     should either return the (computed) attribute value or raise an
     ‘AttributeError’ exception.  The *note object: a9b. class itself
     does not provide this method.

     Note that if the attribute is found through the normal mechanism,
     ‘__getattr__()’ is not called.  (This is an intentional asymmetry
     between ‘__getattr__()’ and *note __setattr__(): 20de.)  This is
     done both for efficiency reasons and because otherwise
     ‘__getattr__()’ would have no way to access other attributes of the
     instance.  Note that at least for instance variables, you can take
     total control by not inserting any values in the instance attribute
     dictionary (but instead inserting them in another object).  See the
     *note __getattribute__(): bf1. method below for a way to actually
     get total control over attribute access.

 -- Method: object.__getattribute__ (self, name)

     Called unconditionally to implement attribute accesses for
     instances of the class.  If the class also defines *note
     __getattr__(): 4d6, the latter will not be called unless
     ‘__getattribute__()’ either calls it explicitly or raises an *note
     AttributeError: 34e.  This method should return the (computed)
     attribute value or raise an ‘AttributeError’ exception.  In order
     to avoid infinite recursion in this method, its implementation
     should always call the base class method with the same name to
     access any attributes it needs, for example,
     ‘object.__getattribute__(self, name)’.

          Note: This method may still be bypassed when looking up
          special methods as the result of implicit invocation via
          language syntax or *note built-in functions: 20b0.  See *note
          Special method lookup: 2117.

     For certain sensitive attribute accesses, raises an *note auditing
     event: 1a15. ‘object.__getattr__’ with arguments ‘obj’ and ‘name’.

 -- Method: object.__setattr__ (self, name, value)

     Called when an attribute assignment is attempted.  This is called
     instead of the normal mechanism (i.e.  store the value in the
     instance dictionary).  'name' is the attribute name, 'value' is the
     value to be assigned to it.

     If ‘__setattr__()’ wants to assign to an instance attribute, it
     should call the base class method with the same name, for example,
     ‘object.__setattr__(self, name, value)’.

     For certain sensitive attribute assignments, raises an *note
     auditing event: 1a15. ‘object.__setattr__’ with arguments ‘obj’,
     ‘name’, ‘value’.

 -- Method: object.__delattr__ (self, name)

     Like *note __setattr__(): 20de. but for attribute deletion instead
     of assignment.  This should only be implemented if ‘del obj.name’
     is meaningful for the object.

     For certain sensitive attribute deletions, raises an *note auditing
     event: 1a15. ‘object.__delattr__’ with arguments ‘obj’ and ‘name’.

 -- Method: object.__dir__ (self)

     Called when *note dir(): 635. is called on the object.  An iterable
     must be returned.  ‘dir()’ converts the returned iterable to a list
     and sorts it.

* Menu:

* Customizing module attribute access::
* Implementing Descriptors::
* Invoking Descriptors::
* __slots__: __slots__<2>.


File: python.info,  Node: Customizing module attribute access,  Next: Implementing Descriptors,  Up: Customizing attribute access

4.3.3.3 Customizing module attribute access
...........................................

 -- Method: module.__getattr__ ()
 -- Method: module.__dir__ ()

Special names ‘__getattr__’ and ‘__dir__’ can be also used to customize
access to module attributes.  The ‘__getattr__’ function at the module
level should accept one argument which is the name of an attribute and
return the computed value or raise an *note AttributeError: 34e.  If an
attribute is not found on a module object through the normal lookup,
i.e.  *note object.__getattribute__(): bf1, then ‘__getattr__’ is
searched in the module ‘__dict__’ before raising an ‘AttributeError’.
If found, it is called with the attribute name and the result is
returned.

The ‘__dir__’ function should accept no arguments, and return an
iterable of strings that represents the names accessible on module.  If
present, this function overrides the standard *note dir(): 635. search
on a module.

 -- Attribute: module.__class__

For a more fine grained customization of the module behavior (setting
attributes, properties, etc.), one can set the ‘__class__’ attribute of
a module object to a subclass of *note types.ModuleType: e45.  For
example:

     import sys
     from types import ModuleType

     class VerboseModule(ModuleType):
         def __repr__(self):
             return f'Verbose {self.__name__}'

         def __setattr__(self, attr, value):
             print(f'Setting {attr}...')
             super().__setattr__(attr, value)

     sys.modules[__name__].__class__ = VerboseModule

     Note: Defining module ‘__getattr__’ and setting module ‘__class__’
     only affect lookups made using the attribute access syntax –
     directly accessing the module globals (whether by code within the
     module, or via a reference to the module’s globals dictionary) is
     unaffected.

Changed in version 3.5: ‘__class__’ module attribute is now writable.

Added in version 3.7: ‘__getattr__’ and ‘__dir__’ module attributes.

See also
........

PEP 562(1) - Module __getattr__ and __dir__

     Describes the ‘__getattr__’ and ‘__dir__’ functions on modules.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0562/


File: python.info,  Node: Implementing Descriptors,  Next: Invoking Descriptors,  Prev: Customizing module attribute access,  Up: Customizing attribute access

4.3.3.4 Implementing Descriptors
................................

The following methods only apply when an instance of the class
containing the method (a so-called 'descriptor' class) appears in an
'owner' class (the descriptor must be in either the owner’s class
dictionary or in the class dictionary for one of its parents).  In the
examples below, “the attribute” refers to the attribute whose name is
the key of the property in the owner class’ *note __dict__: 55e.  The
*note object: a9b. class itself does not implement any of these
protocols.

 -- Method: object.__get__ (self, instance, owner=None)

     Called to get the attribute of the owner class (class attribute
     access) or of an instance of that class (instance attribute
     access).  The optional 'owner' argument is the owner class, while
     'instance' is the instance that the attribute was accessed through,
     or ‘None’ when the attribute is accessed through the 'owner'.

     This method should return the computed attribute value or raise an
     *note AttributeError: 34e. exception.

     PEP 252(1) specifies that ‘__get__()’ is callable with one or two
     arguments.  Python’s own built-in descriptors support this
     specification; however, it is likely that some third-party tools
     have descriptors that require both arguments.  Python’s own *note
     __getattribute__(): bf1. implementation always passes in both
     arguments whether they are required or not.

 -- Method: object.__set__ (self, instance, value)

     Called to set the attribute on an instance 'instance' of the owner
     class to a new value, 'value'.

     Note, adding ‘__set__()’ or *note __delete__(): 1713. changes the
     kind of descriptor to a “data descriptor”.  See *note Invoking
     Descriptors: 211c. for more details.

 -- Method: object.__delete__ (self, instance)

     Called to delete the attribute on an instance 'instance' of the
     owner class.

Instances of descriptors may also have the ‘__objclass__’ attribute
present:

 -- Attribute: object.__objclass__

     The attribute ‘__objclass__’ is interpreted by the *note inspect:
     7e. module as specifying the class where this object was defined
     (setting this appropriately can assist in runtime introspection of
     dynamic class attributes).  For callables, it may indicate that an
     instance of the given type (or a subclass) is expected or required
     as the first positional argument (for example, CPython sets this
     attribute for unbound methods that are implemented in C).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0252/


File: python.info,  Node: Invoking Descriptors,  Next: __slots__<2>,  Prev: Implementing Descriptors,  Up: Customizing attribute access

4.3.3.5 Invoking Descriptors
............................

In general, a descriptor is an object attribute with “binding behavior”,
one whose attribute access has been overridden by methods in the
descriptor protocol: *note __get__(): 1537, *note __set__(): 211b, and
*note __delete__(): 1713.  If any of those methods are defined for an
object, it is said to be a descriptor.

The default behavior for attribute access is to get, set, or delete the
attribute from an object’s dictionary.  For instance, ‘a.x’ has a lookup
chain starting with ‘a.__dict__['x']’, then ‘type(a).__dict__['x']’, and
continuing through the base classes of ‘type(a)’ excluding metaclasses.

However, if the looked-up value is an object defining one of the
descriptor methods, then Python may override the default behavior and
invoke the descriptor method instead.  Where this occurs in the
precedence chain depends on which descriptor methods were defined and
how they were called.

The starting point for descriptor invocation is a binding, ‘a.x’.  How
the arguments are assembled depends on ‘a’:

Direct Call

     The simplest and least common call is when user code directly
     invokes a descriptor method: ‘x.__get__(a)’.

Instance Binding

     If binding to an object instance, ‘a.x’ is transformed into the
     call: ‘type(a).__dict__['x'].__get__(a, type(a))’.

Class Binding

     If binding to a class, ‘A.x’ is transformed into the call:
     ‘A.__dict__['x'].__get__(None, A)’.

Super Binding

     A dotted lookup such as ‘super(A, a).x’ searches
     ‘a.__class__.__mro__’ for a base class ‘B’ following ‘A’ and then
     returns ‘B.__dict__['x'].__get__(a, A)’.  If not a descriptor, ‘x’
     is returned unchanged.

For instance bindings, the precedence of descriptor invocation depends
on which descriptor methods are defined.  A descriptor can define any
combination of *note __get__(): 1537, *note __set__(): 211b. and *note
__delete__(): 1713.  If it does not define ‘__get__()’, then accessing
the attribute will return the descriptor object itself unless there is a
value in the object’s instance dictionary.  If the descriptor defines
‘__set__()’ and/or ‘__delete__()’, it is a data descriptor; if it
defines neither, it is a non-data descriptor.  Normally, data
descriptors define both ‘__get__()’ and ‘__set__()’, while non-data
descriptors have just the ‘__get__()’ method.  Data descriptors with
‘__get__()’ and ‘__set__()’ (and/or ‘__delete__()’) defined always
override a redefinition in an instance dictionary.  In contrast,
non-data descriptors can be overridden by instances.

Python methods (including those decorated with *note @staticmethod: 419.
and *note @classmethod: 166.) are implemented as non-data descriptors.
Accordingly, instances can redefine and override methods.  This allows
individual instances to acquire behaviors that differ from other
instances of the same class.

The *note property(): 194. function is implemented as a data descriptor.
Accordingly, instances cannot override the behavior of a property.


File: python.info,  Node: __slots__<2>,  Prev: Invoking Descriptors,  Up: Customizing attribute access

4.3.3.6 __slots__
.................

'__slots__' allow us to explicitly declare data members (like
properties) and deny the creation of *note __dict__: 55e. and
'__weakref__' (unless explicitly declared in '__slots__' or available in
a parent.)

The space saved over using *note __dict__: 55e. can be significant.
Attribute lookup speed can be significantly improved as well.

 -- Data: object.__slots__

     This class variable can be assigned a string, iterable, or sequence
     of strings with variable names used by instances.  '__slots__'
     reserves space for the declared variables and prevents the
     automatic creation of *note __dict__: 55e. and '__weakref__' for
     each instance.
Notes on using '__slots__':

   * When inheriting from a class without '__slots__', the *note
     __dict__: 55e. and '__weakref__' attribute of the instances will
     always be accessible.

   * Without a *note __dict__: 55e. variable, instances cannot be
     assigned new variables not listed in the '__slots__' definition.
     Attempts to assign to an unlisted variable name raises *note
     AttributeError: 34e.  If dynamic assignment of new variables is
     desired, then add ‘'__dict__'’ to the sequence of strings in the
     '__slots__' declaration.

   * Without a '__weakref__' variable for each instance, classes
     defining '__slots__' do not support *note weak references: 114. to
     its instances.  If weak reference support is needed, then add
     ‘'__weakref__'’ to the sequence of strings in the '__slots__'
     declaration.

   * '__slots__' are implemented at the class level by creating *note
     descriptors: c70. for each variable name.  As a result, class
     attributes cannot be used to set default values for instance
     variables defined by '__slots__'; otherwise, the class attribute
     would overwrite the descriptor assignment.

   * The action of a '__slots__' declaration is not limited to the class
     where it is defined.  '__slots__' declared in parents are available
     in child classes.  However, instances of a child subclass will get
     a *note __dict__: 55e. and '__weakref__' unless the subclass also
     defines '__slots__' (which should only contain names of any
     'additional' slots).

   * If a class defines a slot also defined in a base class, the
     instance variable defined by the base class slot is inaccessible
     (except by retrieving its descriptor directly from the base class).
     This renders the meaning of the program undefined.  In the future,
     a check may be added to prevent this.

   * *note TypeError: 2c3. will be raised if nonempty '__slots__' are
     defined for a class derived from a *note "variable-length" built-in
     type: 2121. such as *note int: 257, *note bytes: 1c2, and *note
     tuple: 373.

   * Any non-string *note iterable: 126d. may be assigned to
     '__slots__'.

   * If a *note dictionary: 256. is used to assign '__slots__', the
     dictionary keys will be used as the slot names.  The values of the
     dictionary can be used to provide per-attribute docstrings that
     will be recognised by *note inspect.getdoc(): a05. and displayed in
     the output of *note help(): 8e0.

   * *note __class__: 14fc. assignment works only if both classes have
     the same '__slots__'.

   * *note Multiple inheritance: 1e59. with multiple slotted parent
     classes can be used, but only one parent is allowed to have
     attributes created by slots (the other bases must have empty slot
     layouts) - violations raise *note TypeError: 2c3.

   * If an *note iterator: 1ac. is used for '__slots__' then a *note
     descriptor: 1677. is created for each of the iterator’s values.
     However, the '__slots__' attribute will be an empty iterator.


File: python.info,  Node: Customizing class creation,  Next: Customizing instance and subclass checks,  Prev: Customizing attribute access,  Up: Special method names

4.3.3.7 Customizing class creation
..................................

Whenever a class inherits from another class, *note __init_subclass__():
634. is called on the parent class.  This way, it is possible to write
classes which change the behavior of subclasses.  This is closely
related to class decorators, but where class decorators only affect the
specific class they’re applied to, ‘__init_subclass__’ solely applies to
future subclasses of the class defining the method.

 -- Method: classmethod object.__init_subclass__ (cls)

     This method is called whenever the containing class is subclassed.
     'cls' is then the new subclass.  If defined as a normal instance
     method, this method is implicitly converted to a class method.

     Keyword arguments which are given to a new class are passed to the
     parent class’s ‘__init_subclass__’.  For compatibility with other
     classes using ‘__init_subclass__’, one should take out the needed
     keyword arguments and pass the others over to the base class, as
     in:

          class Philosopher:
              def __init_subclass__(cls, /, default_name, **kwargs):
                  super().__init_subclass__(**kwargs)
                  cls.default_name = default_name

          class AustralianPhilosopher(Philosopher, default_name="Bruce"):
              pass

     The default implementation ‘object.__init_subclass__’ does nothing,
     but raises an error if it is called with any arguments.

          Note: The metaclass hint ‘metaclass’ is consumed by the rest
          of the type machinery, and is never passed to
          ‘__init_subclass__’ implementations.  The actual metaclass
          (rather than the explicit hint) can be accessed as
          ‘type(cls)’.

     Added in version 3.6.

When a class is created, ‘type.__new__()’ scans the class variables and
makes callbacks to those with a *note __set_name__(): c6f. hook.

 -- Method: object.__set_name__ (self, owner, name)

     Automatically called at the time the owning class 'owner' is
     created.  The object has been assigned to 'name' in that class:

          class A:
              x = C()  # Automatically calls: x.__set_name__(A, 'x')

     If the class variable is assigned after the class is created,
     ‘__set_name__()’ will not be called automatically.  If needed,
     ‘__set_name__()’ can be called directly:

          class A:
             pass

          c = C()
          A.x = c                  # The hook is not called
          c.__set_name__(A, 'x')   # Manually invoke the hook

     See *note Creating the class object: c6b. for more details.

     Added in version 3.6.

* Menu:

* Metaclasses::
* Resolving MRO entries::
* Determining the appropriate metaclass::
* Preparing the class namespace::
* Executing the class body::
* Creating the class object::
* Uses for metaclasses::


File: python.info,  Node: Metaclasses,  Next: Resolving MRO entries,  Up: Customizing class creation

4.3.3.8 Metaclasses
...................

By default, classes are constructed using *note type(): d71.  The class
body is executed in a new namespace and the class name is bound locally
to the result of ‘type(name, bases, namespace)’.

The class creation process can be customized by passing the ‘metaclass’
keyword argument in the class definition line, or by inheriting from an
existing class that included such an argument.  In the following
example, both ‘MyClass’ and ‘MySubclass’ are instances of ‘Meta’:

     class Meta(type):
         pass

     class MyClass(metaclass=Meta):
         pass

     class MySubclass(MyClass):
         pass

Any other keyword arguments that are specified in the class definition
are passed through to all metaclass operations described below.

When a class definition is executed, the following steps occur:

   * MRO entries are resolved;

   * the appropriate metaclass is determined;

   * the class namespace is prepared;

   * the class body is executed;

   * the class object is created.


File: python.info,  Node: Resolving MRO entries,  Next: Determining the appropriate metaclass,  Prev: Metaclasses,  Up: Customizing class creation

4.3.3.9 Resolving MRO entries
.............................

 -- Method: object.__mro_entries__ (self, bases)

     If a base that appears in a class definition is not an instance of
     *note type: d71, then an ‘__mro_entries__()’ method is searched on
     the base.  If an ‘__mro_entries__()’ method is found, the base is
     substituted with the result of a call to ‘__mro_entries__()’ when
     creating the class.  The method is called with the original bases
     tuple passed to the 'bases' parameter, and must return a tuple of
     classes that will be used instead of the base.  The returned tuple
     may be empty: in these cases, the original base is ignored.

See also
........

*note types.resolve_bases(): bba.

     Dynamically resolve bases that are not instances of *note type:
     d71.

*note types.get_original_bases(): 4d1.

     Retrieve a class’s “original bases” prior to modifications by *note
     __mro_entries__(): b02.

PEP 560(1)

     Core support for typing module and generic types.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0560/


File: python.info,  Node: Determining the appropriate metaclass,  Next: Preparing the class namespace,  Prev: Resolving MRO entries,  Up: Customizing class creation

4.3.3.10 Determining the appropriate metaclass
..............................................

The appropriate metaclass for a class definition is determined as
follows:

   * if no bases and no explicit metaclass are given, then *note type():
     d71. is used;

   * if an explicit metaclass is given and it is 'not' an instance of
     *note type(): d71, then it is used directly as the metaclass;

   * if an instance of *note type(): d71. is given as the explicit
     metaclass, or bases are defined, then the most derived metaclass is
     used.

The most derived metaclass is selected from the explicitly specified
metaclass (if any) and the metaclasses (i.e.  ‘type(cls)’) of all
specified base classes.  The most derived metaclass is one which is a
subtype of 'all' of these candidate metaclasses.  If none of the
candidate metaclasses meets that criterion, then the class definition
will fail with ‘TypeError’.


File: python.info,  Node: Preparing the class namespace,  Next: Executing the class body,  Prev: Determining the appropriate metaclass,  Up: Customizing class creation

4.3.3.11 Preparing the class namespace
......................................

Once the appropriate metaclass has been identified, then the class
namespace is prepared.  If the metaclass has a ‘__prepare__’ attribute,
it is called as ‘namespace = metaclass.__prepare__(name, bases, **kwds)’
(where the additional keyword arguments, if any, come from the class
definition).  The ‘__prepare__’ method should be implemented as a *note
classmethod: 166.  The namespace returned by ‘__prepare__’ is passed in
to ‘__new__’, but when the final class object is created the namespace
is copied into a new ‘dict’.

If the metaclass has no ‘__prepare__’ attribute, then the class
namespace is initialised as an empty ordered mapping.

See also
........

PEP 3115(1) - Metaclasses in Python 3000

     Introduced the ‘__prepare__’ namespace hook

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3115/


File: python.info,  Node: Executing the class body,  Next: Creating the class object,  Prev: Preparing the class namespace,  Up: Customizing class creation

4.3.3.12 Executing the class body
.................................

The class body is executed (approximately) as ‘exec(body, globals(),
namespace)’.  The key difference from a normal call to *note exec():
17f. is that lexical scoping allows the class body (including any
methods) to reference names from the current and outer scopes when the
class definition occurs inside a function.

However, even when the class definition occurs inside the function,
methods defined inside the class still cannot see names defined at the
class scope.  Class variables must be accessed through the first
parameter of instance or class methods, or through the implicit
lexically scoped ‘__class__’ reference described in the next section.


File: python.info,  Node: Creating the class object,  Next: Uses for metaclasses,  Prev: Executing the class body,  Up: Customizing class creation

4.3.3.13 Creating the class object
..................................

Once the class namespace has been populated by executing the class body,
the class object is created by calling ‘metaclass(name, bases,
namespace, **kwds)’ (the additional keywords passed here are the same as
those passed to ‘__prepare__’).

This class object is the one that will be referenced by the
zero-argument form of *note super(): 4de.  ‘__class__’ is an implicit
closure reference created by the compiler if any methods in a class body
refer to either ‘__class__’ or ‘super’.  This allows the zero argument
form of ‘super()’ to correctly identify the class being defined based on
lexical scoping, while the class or instance that was used to make the
current call is identified based on the first argument passed to the
method.

'CPython implementation detail:' In CPython 3.6 and later, the
‘__class__’ cell is passed to the metaclass as a ‘__classcell__’ entry
in the class namespace.  If present, this must be propagated up to the
‘type.__new__’ call in order for the class to be initialised correctly.
Failing to do so will result in a *note RuntimeError: 195. in Python
3.8.

When using the default metaclass *note type: d71, or any metaclass that
ultimately calls ‘type.__new__’, the following additional customization
steps are invoked after creating the class object:

  1. The ‘type.__new__’ method collects all of the attributes in the
     class namespace that define a *note __set_name__(): c6f. method;

  2. Those ‘__set_name__’ methods are called with the class being
     defined and the assigned name of that particular attribute;

  3. The *note __init_subclass__(): 634. hook is called on the immediate
     parent of the new class in its method resolution order.

After the class object is created, it is passed to the class decorators
included in the class definition (if any) and the resulting object is
bound in the local namespace as the defined class.

When a new class is created by ‘type.__new__’, the object provided as
the namespace parameter is copied to a new ordered mapping and the
original object is discarded.  The new copy is wrapped in a read-only
proxy, which becomes the *note __dict__: c7e. attribute of the class
object.

See also
........

PEP 3135(1) - New super

     Describes the implicit ‘__class__’ closure reference

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3135/


File: python.info,  Node: Uses for metaclasses,  Prev: Creating the class object,  Up: Customizing class creation

4.3.3.14 Uses for metaclasses
.............................

The potential uses for metaclasses are boundless.  Some ideas that have
been explored include enum, logging, interface checking, automatic
delegation, automatic property creation, proxies, frameworks, and
automatic resource locking/synchronization.


File: python.info,  Node: Customizing instance and subclass checks,  Next: Emulating generic types,  Prev: Customizing class creation,  Up: Special method names

4.3.3.15 Customizing instance and subclass checks
.................................................

The following methods are used to override the default behavior of the
*note isinstance(): 445. and *note issubclass(): 7c5. built-in
functions.

In particular, the metaclass *note abc.ABCMeta: f4f. implements these
methods in order to allow the addition of Abstract Base Classes (ABCs)
as “virtual base classes” to any class or type (including built-in
types), including other ABCs.

 -- Method: type.__instancecheck__ (self, instance)

     Return true if 'instance' should be considered a (direct or
     indirect) instance of 'class'.  If defined, called to implement
     ‘isinstance(instance, class)’.

 -- Method: type.__subclasscheck__ (self, subclass)

     Return true if 'subclass' should be considered a (direct or
     indirect) subclass of 'class'.  If defined, called to implement
     ‘issubclass(subclass, class)’.

Note that these methods are looked up on the type (metaclass) of a
class.  They cannot be defined as class methods in the actual class.
This is consistent with the lookup of special methods that are called on
instances, only in this case the instance is itself a class.

See also
........

PEP 3119(1) - Introducing Abstract Base Classes

     Includes the specification for customizing *note isinstance(): 445.
     and *note issubclass(): 7c5. behavior through *note
     __instancecheck__(): 212c. and *note __subclasscheck__(): 212d,
     with motivation for this functionality in the context of adding
     Abstract Base Classes (see the *note abc: 4. module) to the
     language.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3119/


File: python.info,  Node: Emulating generic types,  Next: Emulating callable objects,  Prev: Customizing instance and subclass checks,  Up: Special method names

4.3.3.16 Emulating generic types
................................

When using *note type annotations: 45b, it is often useful to
'parameterize' a *note generic type: 43c. using Python’s square-brackets
notation.  For example, the annotation ‘list[int]’ might be used to
signify a *note list: 614. in which all the elements are of type *note
int: 257.

See also
........

PEP 484(1) - Type Hints

     Introducing Python’s framework for type annotations

*note Generic Alias Types: 6b5.

     Documentation for objects representing parameterized generic
     classes

*note Generics: 212f, *note user-defined generics: 4d2. and *note typing.Generic: 15fb.

     Documentation on how to implement generic classes that can be
     parameterized at runtime and understood by static type-checkers.

A class can 'generally' only be parameterized if it defines the special
class method ‘__class_getitem__()’.

 -- Method: classmethod object.__class_getitem__ (cls, key)

     Return an object representing the specialization of a generic class
     by type arguments found in 'key'.

     When defined on a class, ‘__class_getitem__()’ is automatically a
     class method.  As such, there is no need for it to be decorated
     with *note @classmethod: 166. when it is defined.

* Menu:

* The purpose of __class_getitem__::
* __class_getitem__ versus __getitem__::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: The purpose of __class_getitem__,  Next: __class_getitem__ versus __getitem__,  Up: Emulating generic types

4.3.3.17 The purpose of '__class_getitem__'
...........................................

The purpose of *note __class_getitem__(): 73e. is to allow runtime
parameterization of standard-library generic classes in order to more
easily apply *note type hints: 2131. to these classes.

To implement custom generic classes that can be parameterized at runtime
and understood by static type-checkers, users should either inherit from
a standard library class that already implements *note
__class_getitem__(): 73e, or inherit from *note typing.Generic: 15fb,
which has its own implementation of ‘__class_getitem__()’.

Custom implementations of *note __class_getitem__(): 73e. on classes
defined outside of the standard library may not be understood by
third-party type-checkers such as mypy.  Using ‘__class_getitem__()’ on
any class for purposes other than type hinting is discouraged.


File: python.info,  Node: __class_getitem__ versus __getitem__,  Prev: The purpose of __class_getitem__,  Up: Emulating generic types

4.3.3.18 '__class_getitem__' versus '__getitem__'
.................................................

Usually, the *note subscription: 2134. of an object using square
brackets will call the *note __getitem__(): 283. instance method defined
on the object’s class.  However, if the object being subscribed is
itself a class, the class method *note __class_getitem__(): 73e. may be
called instead.  ‘__class_getitem__()’ should return a *note
GenericAlias: 6b5. object if it is properly defined.

Presented with the *note expression: 2135. ‘obj[x]’, the Python
interpreter follows something like the following process to decide
whether *note __getitem__(): 283. or *note __class_getitem__(): 73e.
should be called:

     from inspect import isclass

     def subscribe(obj, x):
         """Return the result of the expression 'obj[x]'"""

         class_of_obj = type(obj)

         # If the class of obj defines __getitem__,
         # call class_of_obj.__getitem__(obj, x)
         if hasattr(class_of_obj, '__getitem__'):
             return class_of_obj.__getitem__(obj, x)

         # Else, if obj is a class and defines __class_getitem__,
         # call obj.__class_getitem__(x)
         elif isclass(obj) and hasattr(obj, '__class_getitem__'):
             return obj.__class_getitem__(x)

         # Else, raise an exception
         else:
             raise TypeError(
                 f"'{class_of_obj.__name__}' object is not subscriptable"
             )

In Python, all classes are themselves instances of other classes.  The
class of a class is known as that class’s *note metaclass: 2136, and
most classes have the *note type: d71. class as their metaclass.  ‘type’
does not define *note __getitem__(): 283, meaning that expressions such
as ‘list[int]’, ‘dict[str, float]’ and ‘tuple[str, bytes]’ all result in
*note __class_getitem__(): 73e. being called:

     >>> # list has class "type" as its metaclass, like most classes:
     >>> type(list)
     <class 'type'>
     >>> type(dict) == type(list) == type(tuple) == type(str) == type(bytes)
     True
     >>> # "list[int]" calls "list.__class_getitem__(int)"
     >>> list[int]
     list[int]
     >>> # list.__class_getitem__ returns a GenericAlias object:
     >>> type(list[int])
     <class 'types.GenericAlias'>

However, if a class has a custom metaclass that defines *note
__getitem__(): 283, subscribing the class may result in different
behaviour.  An example of this can be found in the *note enum: 56.
module:

     >>> from enum import Enum
     >>> class Menu(Enum):
     ...     """A breakfast menu"""
     ...     SPAM = 'spam'
     ...     BACON = 'bacon'
     ...
     >>> # Enum classes have a custom metaclass:
     >>> type(Menu)
     <class 'enum.EnumMeta'>
     >>> # EnumMeta defines __getitem__,
     >>> # so __class_getitem__ is not called,
     >>> # and the result is not a GenericAlias object:
     >>> Menu['SPAM']
     <Menu.SPAM: 'spam'>
     >>> type(Menu['SPAM'])
     <enum 'Menu'>

See also
........

PEP 560(1) - Core Support for typing module and generic types

     Introducing *note __class_getitem__(): 73e, and outlining when a
     *note subscription: 2134. results in ‘__class_getitem__()’ being
     called instead of *note __getitem__(): 283.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0560/


File: python.info,  Node: Emulating callable objects,  Next: Emulating container types,  Prev: Emulating generic types,  Up: Special method names

4.3.3.19 Emulating callable objects
...................................

 -- Method: object.__call__ (self[, args...])

     Called when the instance is “called” as a function; if this method
     is defined, ‘x(arg1, arg2, ...)’ roughly translates to
     ‘type(x).__call__(x, arg1, ...)’.  The *note object: a9b. class
     itself does not provide this method.


File: python.info,  Node: Emulating container types,  Next: Emulating numeric types,  Prev: Emulating callable objects,  Up: Special method names

4.3.3.20 Emulating container types
..................................

The following methods can be defined to implement container objects.
None of them are provided by the *note object: a9b. class itself.
Containers usually are *note sequences: 4f4. (such as *note lists: 614.
or *note tuples: 373.) or *note mappings: 1200. (like *note
dictionaries: 213b.), but can represent other containers as well.  The
first set of methods is used either to emulate a sequence or to emulate
a mapping; the difference is that for a sequence, the allowable keys
should be the integers 'k' for which ‘0 <= k < N’ where 'N' is the
length of the sequence, or *note slice: 46c. objects, which define a
range of items.  It is also recommended that mappings provide the
methods ‘keys()’, ‘values()’, ‘items()’, ‘get()’, ‘clear()’,
‘setdefault()’, ‘pop()’, ‘popitem()’, ‘copy()’, and ‘update()’ behaving
similar to those for Python’s standard *note dictionary: 256. objects.
The *note collections.abc: 1e. module provides a *note MutableMapping:
10f0. *note abstract base class: 11fa. to help create those methods from
a base set of *note __getitem__(): 283, *note __setitem__(): 1313, *note
__delitem__(): 1314, and ‘keys()’.

Mutable sequences should provide methods *note append(): 213c, *note
clear(): 213d, *note count(): 213e, *note extend(): 213f, *note index():
2140, *note insert(): 2141, *note pop(): 2142, *note remove(): 2143, and
*note reverse(): 2144, like Python standard *note list: 614. objects.
Finally, sequence types should implement addition (meaning
concatenation) and multiplication (meaning repetition) by defining the
methods *note __add__(): 2145, *note __radd__(): 2146, *note __iadd__():
2147, *note __mul__(): 2148, *note __rmul__(): 2149. and *note
__imul__(): 214a. described below; they should not define other
numerical operators.

It is recommended that both mappings and sequences implement the *note
__contains__(): 1406. method to allow efficient use of the ‘in’
operator; for mappings, ‘in’ should search the mapping’s keys; for
sequences, it should search through the values.  It is further
recommended that both mappings and sequences implement the *note
__iter__(): c90. method to allow efficient iteration through the
container; for mappings, ‘__iter__()’ should iterate through the
object’s keys; for sequences, it should iterate through the values.

 -- Method: object.__len__ (self)

     Called to implement the built-in function *note len(): 631.  Should
     return the length of the object, an integer ‘>=’ 0.  Also, an
     object that doesn’t define a *note __bool__(): 131d. method and
     whose ‘__len__()’ method returns zero is considered to be false in
     a Boolean context.

     'CPython implementation detail:' In CPython, the length is required
     to be at most *note sys.maxsize: 120a.  If the length is larger
     than ‘sys.maxsize’ some features (such as *note len(): 631.) may
     raise *note OverflowError: 888.  To prevent raising ‘OverflowError’
     by truth value testing, an object must define a *note __bool__():
     131d. method.

 -- Method: object.__length_hint__ (self)

     Called to implement *note operator.length_hint(): fa6.  Should
     return an estimated length for the object (which may be greater or
     less than the actual length).  The length must be an integer ‘>=’
     0.  The return value may also be *note NotImplemented: 7d6, which
     is treated the same as if the ‘__length_hint__’ method didn’t exist
     at all.  This method is purely an optimization and is never
     required for correctness.

     Added in version 3.4.

     Note: Slicing is done exclusively with the following three methods.
     A call like

          a[1:2] = b

     is translated to

          a[slice(1, 2, None)] = b

     and so forth.  Missing slice items are always filled in with
     ‘None’.

 -- Method: object.__getitem__ (self, key)

     Called to implement evaluation of ‘self[key]’.  For *note sequence:
     4f4. types, the accepted keys should be integers.  Optionally, they
     may support *note slice: 46c. objects as well.  Negative index
     support is also optional.  If 'key' is of an inappropriate type,
     *note TypeError: 2c3. may be raised; if 'key' is a value outside
     the set of indexes for the sequence (after any special
     interpretation of negative values), *note IndexError: 1585. should
     be raised.  For *note mapping: 1200. types, if 'key' is missing
     (not in the container), *note KeyError: 345. should be raised.

          Note: *note for: 2f2. loops expect that an *note IndexError:
          1585. will be raised for illegal indexes to allow proper
          detection of the end of the sequence.

          Note: When *note subscripting: 2134. a 'class', the special
          class method *note __class_getitem__(): 73e. may be called
          instead of ‘__getitem__()’.  See *note __class_getitem__
          versus __getitem__: 2133. for more details.

 -- Method: object.__setitem__ (self, key, value)

     Called to implement assignment to ‘self[key]’.  Same note as for
     *note __getitem__(): 283.  This should only be implemented for
     mappings if the objects support changes to the values for keys, or
     if new keys can be added, or for sequences if elements can be
     replaced.  The same exceptions should be raised for improper 'key'
     values as for the ‘__getitem__()’ method.

 -- Method: object.__delitem__ (self, key)

     Called to implement deletion of ‘self[key]’.  Same note as for
     *note __getitem__(): 283.  This should only be implemented for
     mappings if the objects support removal of keys, or for sequences
     if elements can be removed from the sequence.  The same exceptions
     should be raised for improper 'key' values as for the
     ‘__getitem__()’ method.

 -- Method: object.__missing__ (self, key)

     Called by *note dict: 256.*note __getitem__(): 283. to implement
     ‘self[key]’ for dict subclasses when key is not in the dictionary.

 -- Method: object.__iter__ (self)

     This method is called when an *note iterator: 1ac. is required for
     a container.  This method should return a new iterator object that
     can iterate over all the objects in the container.  For mappings,
     it should iterate over the keys of the container.

 -- Method: object.__reversed__ (self)

     Called (if present) by the *note reversed(): 86c. built-in to
     implement reverse iteration.  It should return a new iterator
     object that iterates over all the objects in the container in
     reverse order.

     If the ‘__reversed__()’ method is not provided, the *note
     reversed(): 86c. built-in will fall back to using the sequence
     protocol (*note __len__(): 15da. and *note __getitem__(): 283.).
     Objects that support the sequence protocol should only provide
     ‘__reversed__()’ if they can provide an implementation that is more
     efficient than the one provided by ‘reversed()’.

The membership test operators (*note in: 2f4. and *note not in: 632.)
are normally implemented as an iteration through a container.  However,
container objects can supply the following special method with a more
efficient implementation, which also does not require the object be
iterable.

 -- Method: object.__contains__ (self, item)

     Called to implement membership test operators.  Should return true
     if 'item' is in 'self', false otherwise.  For mapping objects, this
     should consider the keys of the mapping rather than the values or
     the key-item pairs.

     For objects that don’t define ‘__contains__()’, the membership test
     first tries iteration via *note __iter__(): c90, then the old
     sequence iteration protocol via *note __getitem__(): 283, see *note
     this section in the language reference: 214b.


File: python.info,  Node: Emulating numeric types,  Next: With Statement Context Managers,  Prev: Emulating container types,  Up: Special method names

4.3.3.21 Emulating numeric types
................................

The following methods can be defined to emulate numeric objects.
Methods corresponding to operations that are not supported by the
particular kind of number implemented (e.g., bitwise operations for
non-integral numbers) should be left undefined.

 -- Method: object.__add__ (self, other)
 -- Method: object.__sub__ (self, other)
 -- Method: object.__mul__ (self, other)
 -- Method: object.__matmul__ (self, other)
 -- Method: object.__truediv__ (self, other)
 -- Method: object.__floordiv__ (self, other)
 -- Method: object.__mod__ (self, other)
 -- Method: object.__divmod__ (self, other)
 -- Method: object.__pow__ (self, other[, modulo])
 -- Method: object.__lshift__ (self, other)
 -- Method: object.__rshift__ (self, other)
 -- Method: object.__and__ (self, other)
 -- Method: object.__xor__ (self, other)
 -- Method: object.__or__ (self, other)

     These methods are called to implement the binary arithmetic
     operations (‘+’, ‘-’, ‘*’, ‘@’, ‘/’, ‘//’, ‘%’, *note divmod():
     9ac, *note pow(): 9dd, ‘**’, ‘<<’, ‘>>’, ‘&’, ‘^’, ‘|’).  For
     instance, to evaluate the expression ‘x + y’, where 'x' is an
     instance of a class that has an ‘__add__()’ method,
     ‘type(x).__add__(x, y)’ is called.  The ‘__divmod__()’ method
     should be the equivalent to using ‘__floordiv__()’ and ‘__mod__()’;
     it should not be related to ‘__truediv__()’.  Note that ‘__pow__()’
     should be defined to accept an optional third argument if the
     ternary version of the built-in ‘pow()’ function is to be
     supported.

     If one of those methods does not support the operation with the
     supplied arguments, it should return *note NotImplemented: 7d6.

 -- Method: object.__radd__ (self, other)
 -- Method: object.__rsub__ (self, other)
 -- Method: object.__rmul__ (self, other)
 -- Method: object.__rmatmul__ (self, other)
 -- Method: object.__rtruediv__ (self, other)
 -- Method: object.__rfloordiv__ (self, other)
 -- Method: object.__rmod__ (self, other)
 -- Method: object.__rdivmod__ (self, other)
 -- Method: object.__rpow__ (self, other[, modulo])
 -- Method: object.__rlshift__ (self, other)
 -- Method: object.__rrshift__ (self, other)
 -- Method: object.__rand__ (self, other)
 -- Method: object.__rxor__ (self, other)
 -- Method: object.__ror__ (self, other)

     These methods are called to implement the binary arithmetic
     operations (‘+’, ‘-’, ‘*’, ‘@’, ‘/’, ‘//’, ‘%’, *note divmod():
     9ac, *note pow(): 9dd, ‘**’, ‘<<’, ‘>>’, ‘&’, ‘^’, ‘|’) with
     reflected (swapped) operands.  These functions are only called if
     the left operand does not support the corresponding operation (1)
     and the operands are of different types.  (2)  For instance, to
     evaluate the expression ‘x - y’, where 'y' is an instance of a
     class that has an ‘__rsub__()’ method, ‘type(y).__rsub__(y, x)’ is
     called if ‘type(x).__sub__(x, y)’ returns *note NotImplemented:
     7d6.

     Note that ternary *note pow(): 9dd. will not try calling
     ‘__rpow__()’ (the coercion rules would become too complicated).

          Note: If the right operand’s type is a subclass of the left
          operand’s type and that subclass provides a different
          implementation of the reflected method for the operation, this
          method will be called before the left operand’s non-reflected
          method.  This behavior allows subclasses to override their
          ancestors’ operations.

 -- Method: object.__iadd__ (self, other)
 -- Method: object.__isub__ (self, other)
 -- Method: object.__imul__ (self, other)
 -- Method: object.__imatmul__ (self, other)
 -- Method: object.__itruediv__ (self, other)
 -- Method: object.__ifloordiv__ (self, other)
 -- Method: object.__imod__ (self, other)
 -- Method: object.__ipow__ (self, other[, modulo])
 -- Method: object.__ilshift__ (self, other)
 -- Method: object.__irshift__ (self, other)
 -- Method: object.__iand__ (self, other)
 -- Method: object.__ixor__ (self, other)
 -- Method: object.__ior__ (self, other)

     These methods are called to implement the augmented arithmetic
     assignments (‘+=’, ‘-=’, ‘*=’, ‘@=’, ‘/=’, ‘//=’, ‘%=’, ‘**=’,
     ‘<<=’, ‘>>=’, ‘&=’, ‘^=’, ‘|=’).  These methods should attempt to
     do the operation in-place (modifying 'self') and return the result
     (which could be, but does not have to be, 'self').  If a specific
     method is not defined, or if that method returns *note
     NotImplemented: 7d6, the augmented assignment falls back to the
     normal methods.  For instance, if 'x' is an instance of a class
     with an ‘__iadd__()’ method, ‘x += y’ is equivalent to ‘x =
     x.__iadd__(y)’ .  If ‘__iadd__()’ does not exist, or if
     ‘x.__iadd__(y)’ returns ‘NotImplemented’, ‘x.__add__(y)’ and
     ‘y.__radd__(x)’ are considered, as with the evaluation of ‘x + y’.
     In certain situations, augmented assignment can result in
     unexpected errors (see *note Why does a_tuple[i] += [‘item’] raise
     an exception when the addition works?: 2167.), but this behavior is
     in fact part of the data model.

 -- Method: object.__neg__ (self)
 -- Method: object.__pos__ (self)
 -- Method: object.__abs__ (self)
 -- Method: object.__invert__ (self)

     Called to implement the unary arithmetic operations (‘-’, ‘+’,
     *note abs(): 1e45. and ‘~’).

 -- Method: object.__complex__ (self)
 -- Method: object.__int__ (self)
 -- Method: object.__float__ (self)

     Called to implement the built-in functions *note complex(): 2f8,
     *note int(): 257. and *note float(): 2f7.  Should return a value of
     the appropriate type.

 -- Method: object.__index__ (self)

     Called to implement *note operator.index(): 1a78, and whenever
     Python needs to losslessly convert the numeric object to an integer
     object (such as in slicing, or in the built-in *note bin(): 12f0,
     *note hex(): 1317. and *note oct(): 1316. functions).  Presence of
     this method indicates that the numeric object is an integer type.
     Must return an integer.

     If *note __int__(): 71f, *note __float__(): 9d7. and *note
     __complex__(): 5ea. are not defined then corresponding built-in
     functions *note int(): 257, *note float(): 2f7. and *note
     complex(): 2f8. fall back to ‘__index__()’.

 -- Method: object.__round__ (self[, ndigits])
 -- Method: object.__trunc__ (self)
 -- Method: object.__floor__ (self)
 -- Method: object.__ceil__ (self)

     Called to implement the built-in function *note round(): 1322. and
     *note math: 8e. functions *note trunc(): 140c, *note floor(): 140a.
     and *note ceil(): 140b.  Unless 'ndigits' is passed to
     ‘__round__()’ all these methods should return the value of the
     object truncated to an *note Integral: 216f. (typically an *note
     int: 257.).

     The built-in function *note int(): 257. falls back to ‘__trunc__()’
     if neither *note __int__(): 71f. nor *note __index__(): 720. is
     defined.

     Changed in version 3.11: The delegation of *note int(): 257. to
     ‘__trunc__()’ is deprecated.

   ---------- Footnotes ----------

   (1) “Does not support” here means that the class has no such method,
or the method returns *note NotImplemented: 7d6.  Do not set the method
to ‘None’ if you want to force fallback to the right operand’s reflected
method—that will instead have the opposite effect of explicitly
'blocking' such fallback.

   (2) For operands of the same type, it is assumed that if the
non-reflected method – such as *note __add__(): 2145. – fails then the
overall operation is not supported, which is why the reflected method is
not called.


File: python.info,  Node: With Statement Context Managers,  Next: Customizing positional arguments in class pattern matching,  Prev: Emulating numeric types,  Up: Special method names

4.3.3.22 With Statement Context Managers
........................................

A 'context manager' is an object that defines the runtime context to be
established when executing a *note with: 5d5. statement.  The context
manager handles the entry into, and the exit from, the desired runtime
context for the execution of the block of code.  Context managers are
normally invoked using the ‘with’ statement (described in section *note
The with statement: 5d5.), but can also be used by directly invoking
their methods.

Typical uses of context managers include saving and restoring various
kinds of global state, locking and unlocking resources, closing opened
files, etc.

For more information on context managers, see *note Context Manager
Types: 2171.  The *note object: a9b. class itself does not provide the
context manager methods.

 -- Method: object.__enter__ (self)

     Enter the runtime context related to this object.  The *note with:
     5d5. statement will bind this method’s return value to the
     target(s) specified in the ‘as’ clause of the statement, if any.

 -- Method: object.__exit__ (self, exc_type, exc_value, traceback)

     Exit the runtime context related to this object.  The parameters
     describe the exception that caused the context to be exited.  If
     the context was exited without an exception, all three arguments
     will be *note None: 678.

     If an exception is supplied, and the method wishes to suppress the
     exception (i.e., prevent it from being propagated), it should
     return a true value.  Otherwise, the exception will be processed
     normally upon exit from this method.

     Note that ‘__exit__()’ methods should not reraise the passed-in
     exception; this is the caller’s responsibility.

See also
........

PEP 343(1) - The “with” statement

     The specification, background, and examples for the Python *note
     with: 5d5. statement.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0343/


File: python.info,  Node: Customizing positional arguments in class pattern matching,  Next: Emulating buffer types,  Prev: With Statement Context Managers,  Up: Special method names

4.3.3.23 Customizing positional arguments in class pattern matching
...................................................................

When using a class name in a pattern, positional arguments in the
pattern are not allowed by default, i.e.  ‘case MyClass(x, y)’ is
typically invalid without special support in ‘MyClass’.  To be able to
use that kind of pattern, the class needs to define a '__match_args__'
attribute.

 -- Data: object.__match_args__

     This class variable can be assigned a tuple of strings.  When this
     class is used in a class pattern with positional arguments, each
     positional argument will be converted into a keyword argument,
     using the corresponding value in '__match_args__' as the keyword.
     The absence of this attribute is equivalent to setting it to ‘()’.

For example, if ‘MyClass.__match_args__’ is ‘("left", "center",
"right")’ that means that ‘case MyClass(x, y)’ is equivalent to ‘case
MyClass(left=x, center=y)’.  Note that the number of arguments in the
pattern must be smaller than or equal to the number of elements in
'__match_args__'; if it is larger, the pattern match attempt will raise
a *note TypeError: 2c3.

Added in version 3.10.

See also
........

PEP 634(1) - Structural Pattern Matching

     The specification for the Python ‘match’ statement.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/


File: python.info,  Node: Emulating buffer types,  Next: Special method lookup,  Prev: Customizing positional arguments in class pattern matching,  Up: Special method names

4.3.3.24 Emulating buffer types
...............................

The *note buffer protocol: 2e8. provides a way for Python objects to
expose efficient access to a low-level memory array.  This protocol is
implemented by builtin types such as *note bytes: 1c2. and *note
memoryview: 2eb, and third-party libraries may define additional buffer
types.

While buffer types are usually implemented in C, it is also possible to
implement the protocol in Python.

 -- Method: object.__buffer__ (self, flags)

     Called when a buffer is requested from 'self' (for example, by the
     *note memoryview: 2eb. constructor).  The 'flags' argument is an
     integer representing the kind of buffer requested, affecting for
     example whether the returned buffer is read-only or writable.
     *note inspect.BufferFlags: 463. provides a convenient way to
     interpret the flags.  The method must return a ‘memoryview’ object.

 -- Method: object.__release_buffer__ (self, buffer)

     Called when a buffer is no longer needed.  The 'buffer' argument is
     a *note memoryview: 2eb. object that was previously returned by
     *note __buffer__(): 462.  The method must release any resources
     associated with the buffer.  This method should return ‘None’.
     Buffer objects that do not need to perform any cleanup are not
     required to implement this method.

Added in version 3.12.

See also
........

PEP 688(1) - Making the buffer protocol accessible in Python

     Introduces the Python ‘__buffer__’ and ‘__release_buffer__’
     methods.

*note collections.abc.Buffer: 2e9.

     ABC for buffer types.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0688/


File: python.info,  Node: Special method lookup,  Prev: Emulating buffer types,  Up: Special method names

4.3.3.25 Special method lookup
..............................

For custom classes, implicit invocations of special methods are only
guaranteed to work correctly if defined on an object’s type, not in the
object’s instance dictionary.  That behaviour is the reason why the
following code raises an exception:

     >>> class C:
     ...     pass
     ...
     >>> c = C()
     >>> c.__len__ = lambda: 5
     >>> len(c)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: object of type 'C' has no len()

The rationale behind this behaviour lies with a number of special
methods such as *note __hash__(): b14. and *note __repr__(): 61f. that
are implemented by all objects, including type objects.  If the implicit
lookup of these methods used the conventional lookup process, they would
fail when invoked on the type object itself:

     >>> 1 .__hash__() == hash(1)
     True
     >>> int.__hash__() == hash(int)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: descriptor '__hash__' of 'int' object needs an argument

Incorrectly attempting to invoke an unbound method of a class in this
way is sometimes referred to as ‘metaclass confusion’, and is avoided by
bypassing the instance when looking up special methods:

     >>> type(1).__hash__(1) == hash(1)
     True
     >>> type(int).__hash__(int) == hash(int)
     True

In addition to bypassing any instance attributes in the interest of
correctness, implicit special method lookup generally also bypasses the
*note __getattribute__(): bf1. method even of the object’s metaclass:

     >>> class Meta(type):
     ...     def __getattribute__(*args):
     ...         print("Metaclass getattribute invoked")
     ...         return type.__getattribute__(*args)
     ...
     >>> class C(object, metaclass=Meta):
     ...     def __len__(self):
     ...         return 10
     ...     def __getattribute__(*args):
     ...         print("Class getattribute invoked")
     ...         return object.__getattribute__(*args)
     ...
     >>> c = C()
     >>> c.__len__()                 # Explicit lookup via instance
     Class getattribute invoked
     10
     >>> type(c).__len__(c)          # Explicit lookup via type
     Metaclass getattribute invoked
     10
     >>> len(c)                      # Implicit lookup
     10

Bypassing the *note __getattribute__(): bf1. machinery in this fashion
provides significant scope for speed optimisations within the
interpreter, at the cost of some flexibility in the handling of special
methods (the special method 'must' be set on the class object itself in
order to be consistently invoked by the interpreter).


File: python.info,  Node: Coroutines,  Prev: Special method names,  Up: Data model

4.3.4 Coroutines
----------------

* Menu:

* Awaitable Objects::
* Coroutine Objects::
* Asynchronous Iterators::
* Asynchronous Context Managers::


File: python.info,  Node: Awaitable Objects,  Next: Coroutine Objects,  Up: Coroutines

4.3.4.1 Awaitable Objects
.........................

An *note awaitable: 1ad. object generally implements an *note
__await__(): da3. method.  *note Coroutine objects: 494. returned from
*note async def: 5d4. functions are awaitable.

     Note: The *note generator iterator: bff. objects returned from
     generators decorated with *note types.coroutine(): ebc. are also
     awaitable, but they do not implement *note __await__(): da3.

 -- Method: object.__await__ (self)

     Must return an *note iterator: 1ac.  Should be used to implement
     *note awaitable: 1ad. objects.  For instance, *note asyncio.Future:
     bec. implements this method to be compatible with the *note await:
     1b9. expression.  The *note object: a9b. class itself is not
     awaitable and does not provide this method.

          Note: The language doesn’t place any restriction on the type
          or value of the objects yielded by the iterator returned by
          ‘__await__’, as this is specific to the implementation of the
          asynchronous execution framework (e.g.  *note asyncio: a.)
          that will be managing the *note awaitable: 1ad. object.

Added in version 3.5.

See also
........

PEP 492(1) for additional information about awaitable objects.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/


File: python.info,  Node: Coroutine Objects,  Next: Asynchronous Iterators,  Prev: Awaitable Objects,  Up: Coroutines

4.3.4.2 Coroutine Objects
.........................

*note Coroutine objects: 494. are *note awaitable: 1ad. objects.  A
coroutine’s execution can be controlled by calling *note __await__():
da3. and iterating over the result.  When the coroutine has finished
executing and returns, the iterator raises *note StopIteration: c1b, and
the exception’s *note value: 217a. attribute holds the return value.  If
the coroutine raises an exception, it is propagated by the iterator.
Coroutines should not directly raise unhandled ‘StopIteration’
exceptions.

Coroutines also have the methods listed below, which are analogous to
those of generators (see *note Generator-iterator methods: 217b.).
However, unlike generators, coroutines do not directly support
iteration.

Changed in version 3.5.2: It is a *note RuntimeError: 195. to await on a
coroutine more than once.

 -- Method: coroutine.send (value)

     Starts or resumes execution of the coroutine.  If 'value' is
     ‘None’, this is equivalent to advancing the iterator returned by
     *note __await__(): da3.  If 'value' is not ‘None’, this method
     delegates to the *note send(): 217d. method of the iterator that
     caused the coroutine to suspend.  The result (return value, *note
     StopIteration: c1b, or other exception) is the same as when
     iterating over the ‘__await__()’ return value, described above.

 -- Method: coroutine.throw (value)

 -- Method: coroutine.throw (type[, value[, traceback]])

     Raises the specified exception in the coroutine.  This method
     delegates to the *note throw(): 4fb. method of the iterator that
     caused the coroutine to suspend, if it has such a method.
     Otherwise, the exception is raised at the suspension point.  The
     result (return value, *note StopIteration: c1b, or other exception)
     is the same as when iterating over the *note __await__(): da3.
     return value, described above.  If the exception is not caught in
     the coroutine, it propagates back to the caller.

     Changed in version 3.12: The second signature (type[, value[,
     traceback]]) is deprecated and may be removed in a future version
     of Python.

 -- Method: coroutine.close ()

     Causes the coroutine to clean itself up and exit.  If the coroutine
     is suspended, this method first delegates to the *note close():
     15df. method of the iterator that caused the coroutine to suspend,
     if it has such a method.  Then it raises *note GeneratorExit: 1414.
     at the suspension point, causing the coroutine to immediately clean
     itself up.  Finally, the coroutine is marked as having finished
     executing, even if it was never started.

     Coroutine objects are automatically closed using the above process
     when they are about to be destroyed.


File: python.info,  Node: Asynchronous Iterators,  Next: Asynchronous Context Managers,  Prev: Coroutine Objects,  Up: Coroutines

4.3.4.3 Asynchronous Iterators
..............................

An 'asynchronous iterator' can call asynchronous code in its ‘__anext__’
method.

Asynchronous iterators can be used in an *note async for: ac0.
statement.

The *note object: a9b. class itself does not provide these methods.

 -- Method: object.__aiter__ (self)

     Must return an 'asynchronous iterator' object.

 -- Method: object.__anext__ (self)

     Must return an 'awaitable' resulting in a next value of the
     iterator.  Should raise a *note StopAsyncIteration: 1bbe. error
     when the iteration is over.

An example of an asynchronous iterable object:

     class Reader:
         async def readline(self):
             ...

         def __aiter__(self):
             return self

         async def __anext__(self):
             val = await self.readline()
             if val == b'':
                 raise StopAsyncIteration
             return val

Added in version 3.5.

Changed in version 3.7: Prior to Python 3.7, *note __aiter__(): c1c.
could return an 'awaitable' that would resolve to an *note asynchronous
iterator: 1ab.

Starting with Python 3.7, *note __aiter__(): c1c. must return an
asynchronous iterator object.  Returning anything else will result in a
*note TypeError: 2c3. error.


File: python.info,  Node: Asynchronous Context Managers,  Prev: Asynchronous Iterators,  Up: Coroutines

4.3.4.4 Asynchronous Context Managers
.....................................

An 'asynchronous context manager' is a 'context manager' that is able to
suspend execution in its ‘__aenter__’ and ‘__aexit__’ methods.

Asynchronous context managers can be used in an *note async with: 5d8.
statement.

The *note object: a9b. class itself does not provide these methods.

 -- Method: object.__aenter__ (self)

     Semantically similar to *note __enter__(): 5cb, the only difference
     being that it must return an 'awaitable'.

 -- Method: object.__aexit__ (self, exc_type, exc_value, traceback)

     Semantically similar to *note __exit__(): 1349, the only difference
     being that it must return an 'awaitable'.

An example of an asynchronous context manager class:

     class AsyncContextManager:
         async def __aenter__(self):
             await log('entering context')

         async def __aexit__(self, exc_type, exc, tb):
             await log('exiting context')

Added in version 3.5.


File: python.info,  Node: Execution model,  Next: The import system,  Prev: Data model,  Up: The Python Language Reference

4.4 Execution model
===================

* Menu:

* Structure of a program::
* Naming and binding::
* Exceptions: Exceptions<2>.


File: python.info,  Node: Structure of a program,  Next: Naming and binding,  Up: Execution model

4.4.1 Structure of a program
----------------------------

A Python program is constructed from code blocks.  A 'block' is a piece
of Python program text that is executed as a unit.  The following are
blocks: a module, a function body, and a class definition.  Each command
typed interactively is a block.  A script file (a file given as standard
input to the interpreter or specified as a command line argument to the
interpreter) is a code block.  A script command (a command specified on
the interpreter command line with the *note -c: 5e3. option) is a code
block.  A module run as a top level script (as module ‘__main__’) from
the command line using a *note -m: 5e4. argument is also a code block.
The string argument passed to the built-in functions *note eval(): 180.
and *note exec(): 17f. is a code block.

A code block is executed in an 'execution frame'.  A frame contains some
administrative information (used for debugging) and determines where and
how execution continues after the code block’s execution has completed.


File: python.info,  Node: Naming and binding,  Next: Exceptions<2>,  Prev: Structure of a program,  Up: Execution model

4.4.2 Naming and binding
------------------------

* Menu:

* Binding of names::
* Resolution of names::
* Annotation scopes::
* Lazy evaluation::
* Builtins and restricted execution::
* Interaction with dynamic features::


File: python.info,  Node: Binding of names,  Next: Resolution of names,  Up: Naming and binding

4.4.2.1 Binding of names
........................

'Names' refer to objects.  Names are introduced by name binding
operations.

The following constructs bind names:

   * formal parameters to functions,

   * class definitions,

   * function definitions,

   * assignment expressions,

   * *note targets: 218b. that are identifiers if occurring in an
     assignment:

        + *note for: 2f2. loop header,

        + after ‘as’ in a *note with: 5d5. statement, *note except: 18b.
          clause, *note except*: 5bb. clause, or in the as-pattern in
          structural pattern matching,

        + in a capture pattern in structural pattern matching

   * *note import: 5e5. statements.

   * *note type: 43b. statements.

   * *note type parameter lists: 2b3.

The ‘import’ statement of the form ‘from ... import *’ binds all names
defined in the imported module, except those beginning with an
underscore.  This form may only be used at the module level.

A target occurring in a *note del: 18c2. statement is also considered
bound for this purpose (though the actual semantics are to unbind the
name).

Each assignment or import statement occurs within a block defined by a
class or function definition or at the module level (the top-level code
block).

If a name is bound in a block, it is a local variable of that block,
unless declared as *note nonlocal: 12ef. or *note global: 18a.  If a
name is bound at the module level, it is a global variable.  (The
variables of the module code block are local and global.)  If a variable
is used in a code block but not defined there, it is a *note free
variable: 218c.

Each occurrence of a name in the program text refers to the 'binding' of
that name established by the following name resolution rules.


File: python.info,  Node: Resolution of names,  Next: Annotation scopes,  Prev: Binding of names,  Up: Naming and binding

4.4.2.2 Resolution of names
...........................

A 'scope' defines the visibility of a name within a block.  If a local
variable is defined in a block, its scope includes that block.  If the
definition occurs in a function block, the scope extends to any blocks
contained within the defining one, unless a contained block introduces a
different binding for the name.

When a name is used in a code block, it is resolved using the nearest
enclosing scope.  The set of all such scopes visible to a code block is
called the block’s 'environment'.

When a name is not found at all, a *note NameError: 442. exception is
raised.  If the current scope is a function scope, and the name refers
to a local variable that has not yet been bound to a value at the point
where the name is used, an *note UnboundLocalError: 1586. exception is
raised.  ‘UnboundLocalError’ is a subclass of ‘NameError’.

If a name binding operation occurs anywhere within a code block, all
uses of the name within the block are treated as references to the
current block.  This can lead to errors when a name is used within a
block before it is bound.  This rule is subtle.  Python lacks
declarations and allows name binding operations to occur anywhere within
a code block.  The local variables of a code block can be determined by
scanning the entire text of the block for name binding operations.  See
*note the FAQ entry on UnboundLocalError: 218f. for examples.

If the *note global: 18a. statement occurs within a block, all uses of
the names specified in the statement refer to the bindings of those
names in the top-level namespace.  Names are resolved in the top-level
namespace by searching the global namespace, i.e.  the namespace of the
module containing the code block, and the builtins namespace, the
namespace of the module *note builtins: 12.  The global namespace is
searched first.  If the names are not found there, the builtins
namespace is searched next.  If the names are also not found in the
builtins namespace, new variables are created in the global namespace.
The global statement must precede all uses of the listed names.

The *note global: 18a. statement has the same scope as a name binding
operation in the same block.  If the nearest enclosing scope for a free
variable contains a global statement, the free variable is treated as a
global.

The *note nonlocal: 12ef. statement causes corresponding names to refer
to previously bound variables in the nearest enclosing function scope.
*note SyntaxError: 18d. is raised at compile time if the given name does
not exist in any enclosing function scope.  *note Type parameters: 2b3.
cannot be rebound with the ‘nonlocal’ statement.

The namespace for a module is automatically created the first time a
module is imported.  The main module for a script is always called *note
__main__: 1.

Class definition blocks and arguments to *note exec(): 17f. and *note
eval(): 180. are special in the context of name resolution.  A class
definition is an executable statement that may use and define names.
These references follow the normal rules for name resolution with an
exception that unbound local variables are looked up in the global
namespace.  The namespace of the class definition becomes the attribute
dictionary of the class.  The scope of names defined in a class block is
limited to the class block; it does not extend to the code blocks of
methods.  This includes comprehensions and generator expressions, but it
does not include *note annotation scopes: 188, which have access to
their enclosing class scopes.  This means that the following will fail:

     class A:
         a = 42
         b = list(a + i for i in range(10))

However, the following will succeed:

     class A:
         type Alias = Nested
         class Nested: pass

     print(A.Alias.__value__)  # <type 'A.Nested'>


File: python.info,  Node: Annotation scopes,  Next: Lazy evaluation,  Prev: Resolution of names,  Up: Naming and binding

4.4.2.3 Annotation scopes
.........................

*note Type parameter lists: 2b3. and *note type: 43b. statements
introduce 'annotation scopes', which behave mostly like function scopes,
but with some exceptions discussed below.  *note Annotations: 45b.
currently do not use annotation scopes, but they are expected to use
annotation scopes in Python 3.13 when PEP 649(1) is implemented.

Annotation scopes are used in the following contexts:

   * Type parameter lists for *note generic type aliases: 459.

   * Type parameter lists for *note generic functions: 456.  A generic
     function’s annotations are executed within the annotation scope,
     but its defaults and decorators are not.

   * Type parameter lists for *note generic classes: 455.  A generic
     class’s base classes and keyword arguments are executed within the
     annotation scope, but its decorators are not.

   * The bounds, constraints, and default values for type parameters
     (*note lazily evaluated: 45a.).

   * The value of type aliases (*note lazily evaluated: 45a.).

Annotation scopes differ from function scopes in the following ways:

   * Annotation scopes have access to their enclosing class namespace.
     If an annotation scope is immediately within a class scope, or
     within another annotation scope that is immediately within a class
     scope, the code in the annotation scope can use names defined in
     the class scope as if it were executed directly within the class
     body.  This contrasts with regular functions defined within
     classes, which cannot access names defined in the class scope.

   * Expressions in annotation scopes cannot contain *note yield: 9d8,
     ‘yield from’, *note await: 1b9, or *note ;=: 2191. expressions.
     (These expressions are allowed in other scopes contained within the
     annotation scope.)

   * Names defined in annotation scopes cannot be rebound with *note
     nonlocal: 12ef. statements in inner scopes.  This includes only
     type parameters, as no other syntactic elements that can appear
     within annotation scopes can introduce new names.

   * While annotation scopes have an internal name, that name is not
     reflected in the *note qualified name: 1acb. of objects defined
     within the scope.  Instead, the *note __qualname__: 10a3. of such
     objects is as if the object were defined in the enclosing scope.

Added in version 3.12: Annotation scopes were introduced in Python 3.12
as part of PEP 695(2).

Changed in version 3.13: Annotation scopes are also used for type
parameter defaults, as introduced by PEP 696(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0649/

   (2) https://peps.python.org/pep-0695/

   (3) https://peps.python.org/pep-0696/


File: python.info,  Node: Lazy evaluation,  Next: Builtins and restricted execution,  Prev: Annotation scopes,  Up: Naming and binding

4.4.2.4 Lazy evaluation
.......................

The values of type aliases created through the *note type: 43b.
statement are 'lazily evaluated'.  The same applies to the bounds,
constraints, and default values of type variables created through the
*note type parameter syntax: 2b3.  This means that they are not
evaluated when the type alias or type variable is created.  Instead,
they are only evaluated when doing so is necessary to resolve an
attribute access.

Example:

     >>> type Alias = 1/0
     >>> Alias.__value__
     Traceback (most recent call last):
       ...
     ZeroDivisionError: division by zero
     >>> def func[T: 1/0](): pass
     >>> T = func.__type_params__[0]
     >>> T.__bound__
     Traceback (most recent call last):
       ...
     ZeroDivisionError: division by zero

Here the exception is raised only when the ‘__value__’ attribute of the
type alias or the ‘__bound__’ attribute of the type variable is
accessed.

This behavior is primarily useful for references to types that have not
yet been defined when the type alias or type variable is created.  For
example, lazy evaluation enables creation of mutually recursive type
aliases:

     from typing import Literal

     type SimpleExpr = int | Parenthesized
     type Parenthesized = tuple[Literal["("], Expr, Literal[")"]]
     type Expr = SimpleExpr | tuple[SimpleExpr, Literal["+", "-"], Expr]

Lazily evaluated values are evaluated in *note annotation scope: 188,
which means that names that appear inside the lazily evaluated value are
looked up as if they were used in the immediately enclosing scope.

Added in version 3.12.


File: python.info,  Node: Builtins and restricted execution,  Next: Interaction with dynamic features,  Prev: Lazy evaluation,  Up: Naming and binding

4.4.2.5 Builtins and restricted execution
.........................................

'CPython implementation detail:' Users should not touch ‘__builtins__’;
it is strictly an implementation detail.  Users wanting to override
values in the builtins namespace should *note import: 5e5. the *note
builtins: 12. module and modify its attributes appropriately.

The builtins namespace associated with the execution of a code block is
actually found by looking up the name ‘__builtins__’ in its global
namespace; this should be a dictionary or a module (in the latter case
the module’s dictionary is used).  By default, when in the *note
__main__: 1. module, ‘__builtins__’ is the built-in module *note
builtins: 12.; when in any other module, ‘__builtins__’ is an alias for
the dictionary of the ‘builtins’ module itself.


File: python.info,  Node: Interaction with dynamic features,  Prev: Builtins and restricted execution,  Up: Naming and binding

4.4.2.6 Interaction with dynamic features
.........................................

Name resolution of free variables occurs at runtime, not at compile
time.  This means that the following code will print 42:

     i = 10
     def f():
         print(i)
     i = 42
     f()

The *note eval(): 180. and *note exec(): 17f. functions do not have
access to the full environment for resolving names.  Names may be
resolved in the local and global namespaces of the caller.  Free
variables are not resolved in the nearest enclosing namespace, but in
the global namespace.  (1)  The ‘exec()’ and ‘eval()’ functions have
optional arguments to override the global and local namespace.  If only
one namespace is specified, it is used for both.

   ---------- Footnotes ----------

   (1) This limitation occurs because the code that is executed by these
operations is not available at the time the module is compiled.


File: python.info,  Node: Exceptions<2>,  Prev: Naming and binding,  Up: Execution model

4.4.3 Exceptions
----------------

Exceptions are a means of breaking out of the normal flow of control of
a code block in order to handle errors or other exceptional conditions.
An exception is 'raised' at the point where the error is detected; it
may be 'handled' by the surrounding code block or by any code block that
directly or indirectly invoked the code block where the error occurred.

The Python interpreter raises an exception when it detects a run-time
error (such as division by zero).  A Python program can also explicitly
raise an exception with the *note raise: 5f0. statement.  Exception
handlers are specified with the *note try: 6ec. … *note except: 18b.
statement.  The *note finally: 9d5. clause of such a statement can be
used to specify cleanup code which does not handle the exception, but is
executed whether an exception occurred or not in the preceding code.

Python uses the “termination” model of error handling: an exception
handler can find out what happened and continue execution at an outer
level, but it cannot repair the cause of the error and retry the failing
operation (except by re-entering the offending piece of code from the
top).

When an exception is not handled at all, the interpreter terminates
execution of the program, or returns to its interactive main loop.  In
either case, it prints a stack traceback, except when the exception is
*note SystemExit: d69.

Exceptions are identified by class instances.  The *note except: 18b.
clause is selected depending on the class of the instance: it must
reference the class of the instance or a *note non-virtual base class:
11fa. thereof.  The instance can be received by the handler and can
carry additional information about the exceptional condition.

     Note: Exception messages are not part of the Python API. Their
     contents may change from one version of Python to the next without
     warning and should not be relied on by code which will run under
     multiple versions of the interpreter.

See also the description of the *note try: 6ec. statement in section
*note The try statement: 6ec. and *note raise: 5f0. statement in section
*note The raise statement: 5f0.


File: python.info,  Node: The import system,  Next: Expressions,  Prev: Execution model,  Up: The Python Language Reference

4.5 The import system
=====================

Python code in one *note module: 1772. gains access to the code in
another module by the process of *note importing: 219c. it.  The *note
import: 5e5. statement is the most common way of invoking the import
machinery, but it is not the only way.  Functions such as *note
importlib.import_module(): 51b. and built-in *note __import__(): 8dd.
can also be used to invoke the import machinery.

The *note import: 5e5. statement combines two operations; it searches
for the named module, then it binds the results of that search to a name
in the local scope.  The search operation of the ‘import’ statement is
defined as a call to the *note __import__(): 8dd. function, with the
appropriate arguments.  The return value of ‘__import__()’ is used to
perform the name binding operation of the ‘import’ statement.  See the
‘import’ statement for the exact details of that name binding operation.

A direct call to *note __import__(): 8dd. performs only the module
search and, if found, the module creation operation.  While certain
side-effects may occur, such as the importing of parent packages, and
the updating of various caches (including *note sys.modules: 1655.),
only the *note import: 5e5. statement performs a name binding operation.

When an *note import: 5e5. statement is executed, the standard builtin
*note __import__(): 8dd. function is called.  Other mechanisms for
invoking the import system (such as *note importlib.import_module():
51b.) may choose to bypass ‘__import__()’ and use their own solutions to
implement import semantics.

When a module is first imported, Python searches for the module and if
found, it creates a module object (1), initializing it.  If the named
module cannot be found, a *note ModuleNotFoundError: b61. is raised.
Python implements various strategies to search for the named module when
the import machinery is invoked.  These strategies can be modified and
extended by using various hooks described in the sections below.

Changed in version 3.3: The import system has been updated to fully
implement the second phase of PEP 302(2).  There is no longer any
implicit import machinery - the full import system is exposed through
*note sys.meta_path: d53.  In addition, native namespace package support
has been implemented (see PEP 420(3)).

* Menu:

* importlib: importlib<10>.
* Packages: Packages<2>.
* Searching::
* Loading::
* The Path Based Finder::
* Replacing the standard import system::
* Package Relative Imports::
* Special considerations for __main__::
* References::

   ---------- Footnotes ----------

   (1) See *note types.ModuleType: e45.

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-0420/


File: python.info,  Node: importlib<10>,  Next: Packages<2>,  Up: The import system

4.5.1 ‘importlib’
-----------------

The *note importlib: 77. module provides a rich API for interacting with
the import system.  For example *note importlib.import_module(): 51b.
provides a recommended, simpler API than built-in *note __import__():
8dd. for invoking the import machinery.  Refer to the ‘importlib’
library documentation for additional detail.


File: python.info,  Node: Packages<2>,  Next: Searching,  Prev: importlib<10>,  Up: The import system

4.5.2 Packages
--------------

Python has only one type of module object, and all modules are of this
type, regardless of whether the module is implemented in Python, C, or
something else.  To help organize modules and provide a naming
hierarchy, Python has a concept of *note packages: 20c9.

You can think of packages as the directories on a file system and
modules as files within directories, but don’t take this analogy too
literally since packages and modules need not originate from the file
system.  For the purposes of this documentation, we’ll use this
convenient analogy of directories and files.  Like file system
directories, packages are organized hierarchically, and packages may
themselves contain subpackages, as well as regular modules.

It’s important to keep in mind that all packages are modules, but not
all modules are packages.  Or put another way, packages are just a
special kind of module.  Specifically, any module that contains a
‘__path__’ attribute is considered a package.

All modules have a name.  Subpackage names are separated from their
parent package name by a dot, akin to Python’s standard attribute access
syntax.  Thus you might have a package called *note email: 3b, which in
turn has a subpackage called *note email.mime: 45. and a module within
that subpackage called *note email.mime.text: 4d.

* Menu:

* Regular packages::
* Namespace packages::


File: python.info,  Node: Regular packages,  Next: Namespace packages,  Up: Packages<2>

4.5.2.1 Regular packages
........................

Python defines two types of packages, *note regular packages: 21a0. and
*note namespace packages: 1e06.  Regular packages are traditional
packages as they existed in Python 3.2 and earlier.  A regular package
is typically implemented as a directory containing an ‘__init__.py’
file.  When a regular package is imported, this ‘__init__.py’ file is
implicitly executed, and the objects it defines are bound to names in
the package’s namespace.  The ‘__init__.py’ file can contain the same
Python code that any other module can contain, and Python will add some
additional attributes to the module when it is imported.

For example, the following file system layout defines a top level
‘parent’ package with three subpackages:

     parent/
         __init__.py
         one/
             __init__.py
         two/
             __init__.py
         three/
             __init__.py

Importing ‘parent.one’ will implicitly execute ‘parent/__init__.py’ and
‘parent/one/__init__.py’.  Subsequent imports of ‘parent.two’ or
‘parent.three’ will execute ‘parent/two/__init__.py’ and
‘parent/three/__init__.py’ respectively.


File: python.info,  Node: Namespace packages,  Prev: Regular packages,  Up: Packages<2>

4.5.2.2 Namespace packages
..........................

A namespace package is a composite of various *note portions: 21a3,
where each portion contributes a subpackage to the parent package.
Portions may reside in different locations on the file system.  Portions
may also be found in zip files, on the network, or anywhere else that
Python searches during import.  Namespace packages may or may not
correspond directly to objects on the file system; they may be virtual
modules that have no concrete representation.

Namespace packages do not use an ordinary list for their ‘__path__’
attribute.  They instead use a custom iterable type which will
automatically perform a new search for package portions on the next
import attempt within that package if the path of their parent package
(or *note sys.path: 3b7. for a top level package) changes.

With namespace packages, there is no ‘parent/__init__.py’ file.  In
fact, there may be multiple ‘parent’ directories found during import
search, where each one is provided by a different portion.  Thus
‘parent/one’ may not be physically located next to ‘parent/two’.  In
this case, Python will create a namespace package for the top-level
‘parent’ package whenever it or one of its subpackages is imported.

See also PEP 420(1) for the namespace package specification.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0420/


File: python.info,  Node: Searching,  Next: Loading,  Prev: Packages<2>,  Up: The import system

4.5.3 Searching
---------------

To begin the search, Python needs the *note fully qualified: 1acb. name
of the module (or package, but for the purposes of this discussion, the
difference is immaterial) being imported.  This name may come from
various arguments to the *note import: 5e5. statement, or from the
parameters to the *note importlib.import_module(): 51b. or *note
__import__(): 8dd. functions.

This name will be used in various phases of the import search, and it
may be the dotted path to a submodule, e.g.  ‘foo.bar.baz’.  In this
case, Python first tries to import ‘foo’, then ‘foo.bar’, and finally
‘foo.bar.baz’.  If any of the intermediate imports fail, a *note
ModuleNotFoundError: b61. is raised.

* Menu:

* The module cache::
* Finders and loaders::
* Import hooks::
* The meta path::


File: python.info,  Node: The module cache,  Next: Finders and loaders,  Up: Searching

4.5.3.1 The module cache
........................

The first place checked during import search is *note sys.modules: 1655.
This mapping serves as a cache of all modules that have been previously
imported, including the intermediate paths.  So if ‘foo.bar.baz’ was
previously imported, ‘sys.modules’ will contain entries for ‘foo’,
‘foo.bar’, and ‘foo.bar.baz’.  Each key will have as its value the
corresponding module object.

During import, the module name is looked up in *note sys.modules: 1655.
and if present, the associated value is the module satisfying the
import, and the process completes.  However, if the value is ‘None’,
then a *note ModuleNotFoundError: b61. is raised.  If the module name is
missing, Python will continue searching for the module.

*note sys.modules: 1655. is writable.  Deleting a key may not destroy
the associated module (as other modules may hold references to it), but
it will invalidate the cache entry for the named module, causing Python
to search anew for the named module upon its next import.  The key can
also be assigned to ‘None’, forcing the next import of the module to
result in a *note ModuleNotFoundError: b61.

Beware though, as if you keep a reference to the module object,
invalidate its cache entry in *note sys.modules: 1655, and then
re-import the named module, the two module objects will 'not' be the
same.  By contrast, *note importlib.reload(): 51c. will reuse the 'same'
module object, and simply reinitialise the module contents by rerunning
the module’s code.


File: python.info,  Node: Finders and loaders,  Next: Import hooks,  Prev: The module cache,  Up: Searching

4.5.3.2 Finders and loaders
...........................

If the named module is not found in *note sys.modules: 1655, then
Python’s import protocol is invoked to find and load the module.  This
protocol consists of two conceptual objects, *note finders: 20cd. and
*note loaders: 17c1.  A finder’s job is to determine whether it can find
the named module using whatever strategy it knows about.  Objects that
implement both of these interfaces are referred to as *note importers:
21a8. - they return themselves when they find that they can load the
requested module.

Python includes a number of default finders and importers.  The first
one knows how to locate built-in modules, and the second knows how to
locate frozen modules.  A third default finder searches an *note import
path: 21a9. for modules.  The import path is a list of locations that
may name file system paths or zip files.  It can also be extended to
search for any locatable resource, such as those identified by URLs.

The import machinery is extensible, so new finders can be added to
extend the range and scope of module searching.

Finders do not actually load modules.  If they can find the named
module, they return a 'module spec', an encapsulation of the module’s
import-related information, which the import machinery then uses when
loading the module.

The following sections describe the protocol for finders and loaders in
more detail, including how you can create and register new ones to
extend the import machinery.

Changed in version 3.4: In previous versions of Python, finders returned
*note loaders: 17c1. directly, whereas now they return module specs
which 'contain' loaders.  Loaders are still used during import but have
fewer responsibilities.


File: python.info,  Node: Import hooks,  Next: The meta path,  Prev: Finders and loaders,  Up: Searching

4.5.3.3 Import hooks
....................

The import machinery is designed to be extensible; the primary mechanism
for this are the 'import hooks'.  There are two types of import hooks:
'meta hooks' and 'import path hooks'.

Meta hooks are called at the start of import processing, before any
other import processing has occurred, other than *note sys.modules:
1655. cache look up.  This allows meta hooks to override *note sys.path:
3b7. processing, frozen modules, or even built-in modules.  Meta hooks
are registered by adding new finder objects to *note sys.meta_path: d53,
as described below.

Import path hooks are called as part of *note sys.path: 3b7. (or
‘package.__path__’) processing, at the point where their associated path
item is encountered.  Import path hooks are registered by adding new
callables to *note sys.path_hooks: 105f. as described below.


File: python.info,  Node: The meta path,  Prev: Import hooks,  Up: Searching

4.5.3.4 The meta path
.....................

When the named module is not found in *note sys.modules: 1655, Python
next searches *note sys.meta_path: d53, which contains a list of meta
path finder objects.  These finders are queried in order to see if they
know how to handle the named module.  Meta path finders must implement a
method called *note find_spec(): 86f. which takes three arguments: a
name, an import path, and (optionally) a target module.  The meta path
finder can use any strategy it wants to determine whether it can handle
the named module or not.

If the meta path finder knows how to handle the named module, it returns
a spec object.  If it cannot handle the named module, it returns ‘None’.
If *note sys.meta_path: d53. processing reaches the end of its list
without returning a spec, then a *note ModuleNotFoundError: b61. is
raised.  Any other exceptions raised are simply propagated up, aborting
the import process.

The *note find_spec(): 86f. method of meta path finders is called with
two or three arguments.  The first is the fully qualified name of the
module being imported, for example ‘foo.bar.baz’.  The second argument
is the path entries to use for the module search.  For top-level
modules, the second argument is ‘None’, but for submodules or
subpackages, the second argument is the value of the parent package’s
‘__path__’ attribute.  If the appropriate ‘__path__’ attribute cannot be
accessed, a *note ModuleNotFoundError: b61. is raised.  The third
argument is an existing module object that will be the target of loading
later.  The import system passes in a target module only during reload.

The meta path may be traversed multiple times for a single import
request.  For example, assuming none of the modules involved has already
been cached, importing ‘foo.bar.baz’ will first perform a top level
import, calling ‘mpf.find_spec("foo", None, None)’ on each meta path
finder (‘mpf’).  After ‘foo’ has been imported, ‘foo.bar’ will be
imported by traversing the meta path a second time, calling
‘mpf.find_spec("foo.bar", foo.__path__, None)’.  Once ‘foo.bar’ has been
imported, the final traversal will call ‘mpf.find_spec("foo.bar.baz",
foo.bar.__path__, None)’.

Some meta path finders only support top level imports.  These importers
will always return ‘None’ when anything other than ‘None’ is passed as
the second argument.

Python’s default *note sys.meta_path: d53. has three meta path finders,
one that knows how to import built-in modules, one that knows how to
import frozen modules, and one that knows how to import modules from an
*note import path: 21a9. (i.e.  the *note path based finder: 21ac.).

Changed in version 3.4: The *note find_spec(): 86f. method of meta path
finders replaced ‘find_module()’, which is now deprecated.  While it
will continue to work without change, the import machinery will try it
only if the finder does not implement ‘find_spec()’.

Changed in version 3.10: Use of ‘find_module()’ by the import system now
raises *note ImportWarning: 4fd.

Changed in version 3.12: ‘find_module()’ has been removed.  Use *note
find_spec(): 86f. instead.


File: python.info,  Node: Loading,  Next: The Path Based Finder,  Prev: Searching,  Up: The import system

4.5.4 Loading
-------------

If and when a module spec is found, the import machinery will use it
(and the loader it contains) when loading the module.  Here is an
approximation of what happens during the loading portion of import:

     module = None
     if spec.loader is not None and hasattr(spec.loader, 'create_module'):
         # It is assumed 'exec_module' will also be defined on the loader.
         module = spec.loader.create_module(spec)
     if module is None:
         module = ModuleType(spec.name)
     # The import-related module attributes get set here:
     _init_module_attrs(spec, module)

     if spec.loader is None:
         # unsupported
         raise ImportError
     if spec.origin is None and spec.submodule_search_locations is not None:
         # namespace package
         sys.modules[spec.name] = module
     elif not hasattr(spec.loader, 'exec_module'):
         module = spec.loader.load_module(spec.name)
     else:
         sys.modules[spec.name] = module
         try:
             spec.loader.exec_module(module)
         except BaseException:
             try:
                 del sys.modules[spec.name]
             except KeyError:
                 pass
             raise
     return sys.modules[spec.name]

Note the following details:

   * If there is an existing module object with the given name in *note
     sys.modules: 1655, import will have already returned it.

   * The module will exist in *note sys.modules: 1655. before the loader
     executes the module code.  This is crucial because the module code
     may (directly or indirectly) import itself; adding it to
     ‘sys.modules’ beforehand prevents unbounded recursion in the worst
     case and multiple loading in the best.

   * If loading fails, the failing module – and only the failing module
     – gets removed from *note sys.modules: 1655.  Any module already in
     the ‘sys.modules’ cache, and any module that was successfully
     loaded as a side-effect, must remain in the cache.  This contrasts
     with reloading where even the failing module is left in
     ‘sys.modules’.

   * After the module is created but before execution, the import
     machinery sets the import-related module attributes
     (“_init_module_attrs” in the pseudo-code example above), as
     summarized in a *note later section: 20c3.

   * Module execution is the key moment of loading in which the module’s
     namespace gets populated.  Execution is entirely delegated to the
     loader, which gets to decide what gets populated and how.

   * The module created during loading and passed to exec_module() may
     not be the one returned at the end of import (1).

Changed in version 3.4: The import system has taken over the boilerplate
responsibilities of loaders.  These were previously performed by the
*note importlib.abc.Loader.load_module(): 870. method.

* Menu:

* Loaders::
* Submodules::
* Module specs::
* __path__ attributes on modules::
* Module reprs::
* Cached bytecode invalidation::

   ---------- Footnotes ----------

   (1) The importlib implementation avoids using the return value
directly.  Instead, it gets the module object by looking the module name
up in *note sys.modules: 1655.  The indirect effect of this is that an
imported module may replace itself in ‘sys.modules’.  This is
implementation-specific behavior that is not guaranteed to work in other
Python implementations.


File: python.info,  Node: Loaders,  Next: Submodules,  Up: Loading

4.5.4.1 Loaders
...............

Module loaders provide the critical function of loading: module
execution.  The import machinery calls the *note
importlib.abc.Loader.exec_module(): 871. method with a single argument,
the module object to execute.  Any value returned from ‘exec_module()’
is ignored.

Loaders must satisfy the following requirements:

   * If the module is a Python module (as opposed to a built-in module
     or a dynamically loaded extension), the loader should execute the
     module’s code in the module’s global name space
     (‘module.__dict__’).

   * If the loader cannot execute the module, it should raise an *note
     ImportError: 41c, although any other exception raised during *note
     exec_module(): 871. will be propagated.

In many cases, the finder and loader can be the same object; in such
cases the *note find_spec(): 86f. method would just return a spec with
the loader set to ‘self’.

Module loaders may opt in to creating the module object during loading
by implementing a *note create_module(): cd4. method.  It takes one
argument, the module spec, and returns the new module object to use
during loading.  ‘create_module()’ does not need to set any attributes
on the module object.  If the method returns ‘None’, the import
machinery will create the new module itself.

Added in version 3.4: The *note create_module(): cd4. method of loaders.

Changed in version 3.4: The *note load_module(): 870. method was
replaced by *note exec_module(): 871. and the import machinery assumed
all the boilerplate responsibilities of loading.

For compatibility with existing loaders, the import machinery will use
the ‘load_module()’ method of loaders if it exists and the loader does
not also implement ‘exec_module()’.  However, ‘load_module()’ has been
deprecated and loaders should implement ‘exec_module()’ instead.

The ‘load_module()’ method must implement all the boilerplate loading
functionality described above in addition to executing the module.  All
the same constraints apply, with some additional clarification:

   * If there is an existing module object with the given name in *note
     sys.modules: 1655, the loader must use that existing module.
     (Otherwise, *note importlib.reload(): 51c. will not work
     correctly.)  If the named module does not exist in ‘sys.modules’,
     the loader must create a new module object and add it to
     ‘sys.modules’.

   * The module 'must' exist in *note sys.modules: 1655. before the
     loader executes the module code, to prevent unbounded recursion or
     multiple loading.

   * If loading fails, the loader must remove any modules it has
     inserted into *note sys.modules: 1655, but it must remove 'only'
     the failing module(s), and only if the loader itself has loaded the
     module(s) explicitly.

Changed in version 3.5: A *note DeprecationWarning: 1a5. is raised when
‘exec_module()’ is defined but ‘create_module()’ is not.

Changed in version 3.6: An *note ImportError: 41c. is raised when
‘exec_module()’ is defined but ‘create_module()’ is not.

Changed in version 3.10: Use of ‘load_module()’ will raise *note
ImportWarning: 4fd.


File: python.info,  Node: Submodules,  Next: Module specs,  Prev: Loaders,  Up: Loading

4.5.4.2 Submodules
..................

When a submodule is loaded using any mechanism (e.g.  ‘importlib’ APIs,
the ‘import’ or ‘import-from’ statements, or built-in ‘__import__()’) a
binding is placed in the parent module’s namespace to the submodule
object.  For example, if package ‘spam’ has a submodule ‘foo’, after
importing ‘spam.foo’, ‘spam’ will have an attribute ‘foo’ which is bound
to the submodule.  Let’s say you have the following directory structure:

     spam/
         __init__.py
         foo.py

and ‘spam/__init__.py’ has the following line in it:

     from .foo import Foo

then executing the following puts name bindings for ‘foo’ and ‘Foo’ in
the ‘spam’ module:

     >>> import spam
     >>> spam.foo
     <module 'spam.foo' from '/tmp/imports/spam/foo.py'>
     >>> spam.Foo
     <class 'spam.foo.Foo'>

Given Python’s familiar name binding rules this might seem surprising,
but it’s actually a fundamental feature of the import system.  The
invariant holding is that if you have ‘sys.modules['spam']’ and
‘sys.modules['spam.foo']’ (as you would after the above import), the
latter must appear as the ‘foo’ attribute of the former.


File: python.info,  Node: Module specs,  Next: __path__ attributes on modules,  Prev: Submodules,  Up: Loading

4.5.4.3 Module specs
....................

The import machinery uses a variety of information about each module
during import, especially before loading.  Most of the information is
common to all modules.  The purpose of a module’s spec is to encapsulate
this import-related information on a per-module basis.

Using a spec during import allows state to be transferred between import
system components, e.g.  between the finder that creates the module spec
and the loader that executes it.  Most importantly, it allows the import
machinery to perform the boilerplate operations of loading, whereas
without a module spec the loader had that responsibility.

The module’s spec is exposed as *note module.__spec__: 20c6.  Setting
‘__spec__’ appropriately applies equally to *note modules initialized
during interpreter startup: 21b1.  The one exception is ‘__main__’,
where ‘__spec__’ is *note set to None in some cases: 21b2.

See *note ModuleSpec: 200d. for details on the contents of the module
spec.

Added in version 3.4.


File: python.info,  Node: __path__ attributes on modules,  Next: Module reprs,  Prev: Module specs,  Up: Loading

4.5.4.4 __path__ attributes on modules
......................................

The *note __path__: 1e0c. attribute should be a (possibly empty) *note
sequence: 4f4. of strings enumerating the locations where the package’s
submodules will be found.  By definition, if a module has a ‘__path__’
attribute, it is a *note package: 20c9.

A package’s *note __path__: 1e0c. attribute is used during imports of
its subpackages.  Within the import machinery, it functions much the
same as *note sys.path: 3b7, i.e.  providing a list of locations to
search for modules during import.  However, ‘__path__’ is typically much
more constrained than ‘sys.path’.

The same rules used for *note sys.path: 3b7. also apply to a package’s
‘__path__’.  *note sys.path_hooks: 105f. (described below) are consulted
when traversing a package’s ‘__path__’.

A package’s ‘__init__.py’ file may set or alter the package’s *note
__path__: 1e0c. attribute, and this was typically the way namespace
packages were implemented prior to PEP 420(1).  With the adoption of PEP
420(2), namespace packages no longer need to supply ‘__init__.py’ files
containing only ‘__path__’ manipulation code; the import machinery
automatically sets ‘__path__’ correctly for the namespace package.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0420/

   (2) https://peps.python.org/pep-0420/


File: python.info,  Node: Module reprs,  Next: Cached bytecode invalidation,  Prev: __path__ attributes on modules,  Up: Loading

4.5.4.5 Module reprs
....................

By default, all modules have a usable repr, however depending on the
attributes set above, and in the module’s spec, you can more explicitly
control the repr of module objects.

If the module has a spec (‘__spec__’), the import machinery will try to
generate a repr from it.  If that fails or there is no spec, the import
system will craft a default repr using whatever information is available
on the module.  It will try to use the ‘module.__name__’,
‘module.__file__’, and ‘module.__loader__’ as input into the repr, with
defaults for whatever information is missing.

Here are the exact rules used:

   * If the module has a ‘__spec__’ attribute, the information in the
     spec is used to generate the repr.  The “name”, “loader”, “origin”,
     and “has_location” attributes are consulted.

   * If the module has a ‘__file__’ attribute, this is used as part of
     the module’s repr.

   * If the module has no ‘__file__’ but does have a ‘__loader__’ that
     is not ‘None’, then the loader’s repr is used as part of the
     module’s repr.

   * Otherwise, just use the module’s ‘__name__’ in the repr.

Changed in version 3.12: Use of ‘module_repr()’, having been deprecated
since Python 3.4, was removed in Python 3.12 and is no longer called
during the resolution of a module’s repr.


File: python.info,  Node: Cached bytecode invalidation,  Prev: Module reprs,  Up: Loading

4.5.4.6 Cached bytecode invalidation
....................................

Before Python loads cached bytecode from a ‘.pyc’ file, it checks
whether the cache is up-to-date with the source ‘.py’ file.  By default,
Python does this by storing the source’s last-modified timestamp and
size in the cache file when writing it.  At runtime, the import system
then validates the cache file by checking the stored metadata in the
cache file against the source’s metadata.

Python also supports “hash-based” cache files, which store a hash of the
source file’s contents rather than its metadata.  There are two variants
of hash-based ‘.pyc’ files: checked and unchecked.  For checked
hash-based ‘.pyc’ files, Python validates the cache file by hashing the
source file and comparing the resulting hash with the hash in the cache
file.  If a checked hash-based cache file is found to be invalid, Python
regenerates it and writes a new checked hash-based cache file.  For
unchecked hash-based ‘.pyc’ files, Python simply assumes the cache file
is valid if it exists.  Hash-based ‘.pyc’ files validation behavior may
be overridden with the *note -check-hash-based-pycs: 1ed9. flag.

Changed in version 3.7: Added hash-based ‘.pyc’ files.  Previously,
Python only supported timestamp-based invalidation of bytecode caches.


File: python.info,  Node: The Path Based Finder,  Next: Replacing the standard import system,  Prev: Loading,  Up: The import system

4.5.5 The Path Based Finder
---------------------------

As mentioned previously, Python comes with several default meta path
finders.  One of these, called the *note path based finder: 21ac. (*note
PathFinder: 105e.), searches an *note import path: 21a9, which contains
a list of *note path entries: 21b7.  Each path entry names a location to
search for modules.

The path based finder itself doesn’t know how to import anything.
Instead, it traverses the individual path entries, associating each of
them with a path entry finder that knows how to handle that particular
kind of path.

The default set of path entry finders implement all the semantics for
finding modules on the file system, handling special file types such as
Python source code (‘.py’ files), Python byte code (‘.pyc’ files) and
shared libraries (e.g.  ‘.so’ files).  When supported by the *note
zipimport: 132. module in the standard library, the default path entry
finders also handle loading all of these file types (other than shared
libraries) from zipfiles.

Path entries need not be limited to file system locations.  They can
refer to URLs, database queries, or any other location that can be
specified as a string.

The path based finder provides additional hooks and protocols so that
you can extend and customize the types of searchable path entries.  For
example, if you wanted to support path entries as network URLs, you
could write a hook that implements HTTP semantics to find modules on the
web.  This hook (a callable) would return a *note path entry finder:
10af. supporting the protocol described below, which was then used to
get a loader for the module from the web.

A word of warning: this section and the previous both use the term
'finder', distinguishing between them by using the terms *note meta path
finder: 10ae. and *note path entry finder: 10af.  These two types of
finders are very similar, support similar protocols, and function in
similar ways during the import process, but it’s important to keep in
mind that they are subtly different.  In particular, meta path finders
operate at the beginning of the import process, as keyed off the *note
sys.meta_path: d53. traversal.

By contrast, path entry finders are in a sense an implementation detail
of the path based finder, and in fact, if the path based finder were to
be removed from *note sys.meta_path: d53, none of the path entry finder
semantics would be invoked.

* Menu:

* Path entry finders::
* Path entry finder protocol::


File: python.info,  Node: Path entry finders,  Next: Path entry finder protocol,  Up: The Path Based Finder

4.5.5.1 Path entry finders
..........................

The *note path based finder: 21ac. is responsible for finding and
loading Python modules and packages whose location is specified with a
string *note path entry: 21b7.  Most path entries name locations in the
file system, but they need not be limited to this.

As a meta path finder, the *note path based finder: 21ac. implements the
*note find_spec(): 86f. protocol previously described, however it
exposes additional hooks that can be used to customize how modules are
found and loaded from the *note import path: 21a9.

Three variables are used by the *note path based finder: 21ac, *note
sys.path: 3b7, *note sys.path_hooks: 105f. and *note
sys.path_importer_cache: 5e7.  The ‘__path__’ attributes on package
objects are also used.  These provide additional ways that the import
machinery can be customized.

*note sys.path: 3b7. contains a list of strings providing search
locations for modules and packages.  It is initialized from the *note
PYTHONPATH: 1058. environment variable and various other installation-
and implementation-specific defaults.  Entries in ‘sys.path’ can name
directories on the file system, zip files, and potentially other
“locations” (see the *note site: c7. module) that should be searched for
modules, such as URLs, or database queries.  Only strings should be
present on ‘sys.path’; all other data types are ignored.

The *note path based finder: 21ac. is a *note meta path finder: 10ae, so
the import machinery begins the *note import path: 21a9. search by
calling the path based finder’s *note find_spec(): 104c. method as
described previously.  When the ‘path’ argument to ‘find_spec()’ is
given, it will be a list of string paths to traverse - typically a
package’s ‘__path__’ attribute for an import within that package.  If
the ‘path’ argument is ‘None’, this indicates a top level import and
*note sys.path: 3b7. is used.

The path based finder iterates over every entry in the search path, and
for each of these, looks for an appropriate *note path entry finder:
10af. (*note PathEntryFinder: 876.) for the path entry.  Because this
can be an expensive operation (e.g.  there may be ‘stat()’ call
overheads for this search), the path based finder maintains a cache
mapping path entries to path entry finders.  This cache is maintained in
*note sys.path_importer_cache: 5e7. (despite the name, this cache
actually stores finder objects rather than being limited to *note
importer: 21a8. objects).  In this way, the expensive search for a
particular *note path entry: 21b7. location’s path entry finder need
only be done once.  User code is free to remove cache entries from
‘sys.path_importer_cache’ forcing the path based finder to perform the
path entry search again.

If the path entry is not present in the cache, the path based finder
iterates over every callable in *note sys.path_hooks: 105f.  Each of the
*note path entry hooks: 21b9. in this list is called with a single
argument, the path entry to be searched.  This callable may either
return a *note path entry finder: 10af. that can handle the path entry,
or it may raise *note ImportError: 41c.  An ‘ImportError’ is used by the
path based finder to signal that the hook cannot find a path entry
finder for that *note path entry: 21b7.  The exception is ignored and
*note import path: 21a9. iteration continues.  The hook should expect
either a string or bytes object; the encoding of bytes objects is up to
the hook (e.g.  it may be a file system encoding, UTF-8, or something
else), and if the hook cannot decode the argument, it should raise
‘ImportError’.

If *note sys.path_hooks: 105f. iteration ends with no *note path entry
finder: 10af. being returned, then the path based finder’s *note
find_spec(): 104c. method will store ‘None’ in *note
sys.path_importer_cache: 5e7. (to indicate that there is no finder for
this path entry) and return ‘None’, indicating that this *note meta path
finder: 10ae. could not find the module.

If a *note path entry finder: 10af. 'is' returned by one of the *note
path entry hook: 21b9. callables on *note sys.path_hooks: 105f, then the
following protocol is used to ask the finder for a module spec, which is
then used when loading the module.

The current working directory – denoted by an empty string – is handled
slightly differently from other entries on *note sys.path: 3b7.  First,
if the current working directory is found to not exist, no value is
stored in *note sys.path_importer_cache: 5e7.  Second, the value for the
current working directory is looked up fresh for each module lookup.
Third, the path used for ‘sys.path_importer_cache’ and returned by *note
importlib.machinery.PathFinder.find_spec(): 104c. will be the actual
current working directory and not the empty string.


File: python.info,  Node: Path entry finder protocol,  Prev: Path entry finders,  Up: The Path Based Finder

4.5.5.2 Path entry finder protocol
..................................

In order to support imports of modules and initialized packages and also
to contribute portions to namespace packages, path entry finders must
implement the *note find_spec(): 873. method.

*note find_spec(): 873. takes two arguments: the fully qualified name of
the module being imported, and the (optional) target module.
‘find_spec()’ returns a fully populated spec for the module.  This spec
will always have “loader” set (with one exception).

To indicate to the import machinery that the spec represents a namespace
*note portion: 21a3, the path entry finder sets
‘submodule_search_locations’ to a list containing the portion.

Changed in version 3.4: *note find_spec(): 873. replaced ‘find_loader()’
and ‘find_module()’, both of which are now deprecated, but will be used
if ‘find_spec()’ is not defined.

Older path entry finders may implement one of these two deprecated
methods instead of ‘find_spec()’.  The methods are still respected for
the sake of backward compatibility.  However, if ‘find_spec()’ is
implemented on the path entry finder, the legacy methods are ignored.

‘find_loader()’ takes one argument, the fully qualified name of the
module being imported.  ‘find_loader()’ returns a 2-tuple where the
first item is the loader and the second item is a namespace *note
portion: 21a3.

For backwards compatibility with other implementations of the import
protocol, many path entry finders also support the same, traditional
‘find_module()’ method that meta path finders support.  However path
entry finder ‘find_module()’ methods are never called with a ‘path’
argument (they are expected to record the appropriate path information
from the initial call to the path hook).

The ‘find_module()’ method on path entry finders is deprecated, as it
does not allow the path entry finder to contribute portions to namespace
packages.  If both ‘find_loader()’ and ‘find_module()’ exist on a path
entry finder, the import system will always call ‘find_loader()’ in
preference to ‘find_module()’.

Changed in version 3.10: Calls to ‘find_module()’ and ‘find_loader()’ by
the import system will raise *note ImportWarning: 4fd.

Changed in version 3.12: ‘find_module()’ and ‘find_loader()’ have been
removed.


File: python.info,  Node: Replacing the standard import system,  Next: Package Relative Imports,  Prev: The Path Based Finder,  Up: The import system

4.5.6 Replacing the standard import system
------------------------------------------

The most reliable mechanism for replacing the entire import system is to
delete the default contents of *note sys.meta_path: d53, replacing them
entirely with a custom meta path hook.

If it is acceptable to only alter the behaviour of import statements
without affecting other APIs that access the import system, then
replacing the builtin *note __import__(): 8dd. function may be
sufficient.

To selectively prevent the import of some modules from a hook early on
the meta path (rather than disabling the standard import system
entirely), it is sufficient to raise *note ModuleNotFoundError: b61.
directly from *note find_spec(): 86f. instead of returning ‘None’.  The
latter indicates that the meta path search should continue, while
raising an exception terminates it immediately.


File: python.info,  Node: Package Relative Imports,  Next: Special considerations for __main__,  Prev: Replacing the standard import system,  Up: The import system

4.5.7 Package Relative Imports
------------------------------

Relative imports use leading dots.  A single leading dot indicates a
relative import, starting with the current package.  Two or more leading
dots indicate a relative import to the parent(s) of the current package,
one level per dot after the first.  For example, given the following
package layout:

     package/
         __init__.py
         subpackage1/
             __init__.py
             moduleX.py
             moduleY.py
         subpackage2/
             __init__.py
             moduleZ.py
         moduleA.py

In either ‘subpackage1/moduleX.py’ or ‘subpackage1/__init__.py’, the
following are valid relative imports:

     from .moduleY import spam
     from .moduleY import spam as ham
     from . import moduleY
     from ..subpackage1 import moduleY
     from ..subpackage2.moduleZ import eggs
     from ..moduleA import foo

Absolute imports may use either the ‘import <>’ or ‘from <> import <>’
syntax, but relative imports may only use the second form; the reason
for this is that:

     import XXX.YYY.ZZZ

should expose ‘XXX.YYY.ZZZ’ as a usable expression, but .moduleY is not
a valid expression.


File: python.info,  Node: Special considerations for __main__,  Next: References,  Prev: Package Relative Imports,  Up: The import system

4.5.8 Special considerations for __main__
-----------------------------------------

The *note __main__: 1. module is a special case relative to Python’s
import system.  As noted *note elsewhere: 21b1, the ‘__main__’ module is
directly initialized at interpreter startup, much like *note sys: d9.
and *note builtins: 12.  However, unlike those two, it doesn’t strictly
qualify as a built-in module.  This is because the manner in which
‘__main__’ is initialized depends on the flags and other options with
which the interpreter is invoked.

* Menu:

* __main__.__spec__: __main__ __spec__.


File: python.info,  Node: __main__ __spec__,  Up: Special considerations for __main__

4.5.8.1 __main__.__spec__
.........................

Depending on how *note __main__: 1. is initialized, ‘__main__.__spec__’
gets set appropriately or to ‘None’.

When Python is started with the *note -m: 5e4. option, ‘__spec__’ is set
to the module spec of the corresponding module or package.  ‘__spec__’
is also populated when the ‘__main__’ module is loaded as part of
executing a directory, zipfile or other *note sys.path: 3b7. entry.

In *note the remaining cases: 1ed2. ‘__main__.__spec__’ is set to
‘None’, as the code used to populate the *note __main__: 1. does not
correspond directly with an importable module:

   - interactive prompt

   - *note -c: 5e3. option

   - running from stdin

   - running directly from a source or bytecode file

Note that ‘__main__.__spec__’ is always ‘None’ in the last case, 'even
if' the file could technically be imported directly as a module instead.
Use the *note -m: 5e4. switch if valid module metadata is desired in
*note __main__: 1.

Note also that even when ‘__main__’ corresponds with an importable
module and ‘__main__.__spec__’ is set accordingly, they’re still
considered 'distinct' modules.  This is due to the fact that blocks
guarded by ‘if __name__ == "__main__":’ checks only execute when the
module is used to populate the ‘__main__’ namespace, and not during
normal import.


File: python.info,  Node: References,  Prev: Special considerations for __main__,  Up: The import system

4.5.9 References
----------------

The import machinery has evolved considerably since Python’s early days.
The original specification for packages(1) is still available to read,
although some details have changed since the writing of that document.

The original specification for *note sys.meta_path: d53. was PEP 302(2),
with subsequent extension in PEP 420(3).

PEP 420(4) introduced *note namespace packages: 1e06. for Python 3.3.
PEP 420(5) also introduced the ‘find_loader()’ protocol as an
alternative to ‘find_module()’.

PEP 366(6) describes the addition of the ‘__package__’ attribute for
explicit relative imports in main modules.

PEP 328(7) introduced absolute and explicit relative imports and
initially proposed ‘__name__’ for semantics PEP 366(8) would eventually
specify for ‘__package__’.

PEP 338(9) defines executing modules as scripts.

PEP 451(10) adds the encapsulation of per-module import state in spec
objects.  It also off-loads most of the boilerplate responsibilities of
loaders back onto the import machinery.  These changes allow the
deprecation of several APIs in the import system and also addition of
new methods to finders and loaders.

   ---------- Footnotes ----------

   (1) https://www.python.org/doc/essays/packages/

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-0420/

   (4) https://peps.python.org/pep-0420/

   (5) https://peps.python.org/pep-0420/

   (6) https://peps.python.org/pep-0366/

   (7) https://peps.python.org/pep-0328/

   (8) https://peps.python.org/pep-0366/

   (9) https://peps.python.org/pep-0338/

   (10) https://peps.python.org/pep-0451/


File: python.info,  Node: Expressions,  Next: Simple statements,  Prev: The import system,  Up: The Python Language Reference

4.6 Expressions
===============

This chapter explains the meaning of the elements of expressions in
Python.

'Syntax Notes:' In this and the following chapters, extended BNF
notation will be used to describe syntax, not lexical analysis.  When
(one alternative of) a syntax rule has the form

     name ::= othername

and no semantics are given, the semantics of this form of ‘name’ are the
same as for ‘othername’.

* Menu:

* Arithmetic conversions::
* Atoms::
* Primaries::
* Await expression::
* The power operator::
* Unary arithmetic and bitwise operations::
* Binary arithmetic operations::
* Shifting operations::
* Binary bitwise operations::
* Comparisons::
* Boolean operations::
* Assignment expressions: Assignment expressions<2>.
* Conditional expressions::
* Lambdas::
* Expression lists::
* Evaluation order::
* Operator precedence::


File: python.info,  Node: Arithmetic conversions,  Next: Atoms,  Up: Expressions

4.6.1 Arithmetic conversions
----------------------------

When a description of an arithmetic operator below uses the phrase “the
numeric arguments are converted to a common type”, this means that the
operator implementation for built-in types works as follows:

   * If either argument is a complex number, the other is converted to
     complex;

   * otherwise, if either argument is a floating-point number, the other
     is converted to floating point;

   * otherwise, both must be integers and no conversion is necessary.

Some additional rules apply for certain operators (e.g., a string as a
left argument to the ‘%’ operator).  Extensions must define their own
conversion behavior.


File: python.info,  Node: Atoms,  Next: Primaries,  Prev: Arithmetic conversions,  Up: Expressions

4.6.2 Atoms
-----------

Atoms are the most basic elements of expressions.  The simplest atoms
are identifiers or literals.  Forms enclosed in parentheses, brackets or
braces are also categorized syntactically as atoms.  The syntax for
atoms is:

     atom      ::= *note identifier: 2042. | *note literal: 21cc. | *note enclosure: 21cd.
     enclosure ::= *note parenth_form: 21ce. | *note list_display: 21cf. | *note dict_display: 21d0. | *note set_display: 21d1.
                   | *note generator_expression: 21d2. | *note yield_atom: 21d3.

* Menu:

* Identifiers (Names): Identifiers Names.
* Literals: Literals<2>.
* Parenthesized forms::
* Displays for lists, sets and dictionaries: Displays for lists sets and dictionaries.
* List displays::
* Set displays::
* Dictionary displays::
* Generator expressions::
* Yield expressions::


File: python.info,  Node: Identifiers Names,  Next: Literals<2>,  Up: Atoms

4.6.2.1 Identifiers (Names)
...........................

An identifier occurring as an atom is a name.  See section *note
Identifiers and keywords: 2040. for lexical definition and section *note
Naming and binding: 20a9. for documentation of naming and binding.

When the name is bound to an object, evaluation of the atom yields that
object.  When a name is not bound, an attempt to evaluate it raises a
*note NameError: 442. exception.

* Menu:

* Private name mangling::


File: python.info,  Node: Private name mangling,  Up: Identifiers Names

4.6.2.2 Private name mangling
.............................

When an identifier that textually occurs in a class definition begins
with two or more underscore characters and does not end in two or more
underscores, it is considered a 'private name' of that class.

See also
........

The *note class specifications: 131f.

More precisely, private names are transformed to a longer form before
code is generated for them.  If the transformed name is longer than 255
characters, implementation-defined truncation may happen.

The transformation is independent of the syntactical context in which
the identifier is used but only the following private identifiers are
mangled:

   - Any name used as the name of a variable that is assigned or read or
     any name of an attribute being accessed.

     The *note __name__: 10a4. attribute of nested functions, classes,
     and type aliases is however not mangled.

   - The name of imported modules, e.g., ‘__spam’ in ‘import __spam’.
     If the module is part of a package (i.e., its name contains a dot),
     the name is 'not' mangled, e.g., the ‘__foo’ in ‘import __foo.bar’
     is not mangled.

   - The name of an imported member, e.g., ‘__f’ in ‘from spam import
     __f’.

The transformation rule is defined as follows:

   - The class name, with leading underscores removed and a single
     leading underscore inserted, is inserted in front of the
     identifier, e.g., the identifier ‘__spam’ occurring in a class
     named ‘Foo’, ‘_Foo’ or ‘__Foo’ is transformed to ‘_Foo__spam’.

   - If the class name consists only of underscores, the transformation
     is the identity, e.g., the identifier ‘__spam’ occurring in a class
     named ‘_’ or ‘__’ is left as is.


File: python.info,  Node: Literals<2>,  Next: Parenthesized forms,  Prev: Identifiers Names,  Up: Atoms

4.6.2.3 Literals
................

Python supports string and bytes literals and various numeric literals:

     literal ::= *note stringliteral: 2051. | *note bytesliteral: 205a.
                 | *note integer: 2075. | *note floatnumber: 2081. | *note imagnumber: 2089.

Evaluation of a literal yields an object of the given type (string,
bytes, integer, floating-point number, complex number) with the given
value.  The value may be approximated in the case of floating-point and
imaginary (complex) literals.  See section *note Literals: 204e. for
details.

All literals correspond to immutable data types, and hence the object’s
identity is less important than its value.  Multiple evaluations of
literals with the same value (either the same occurrence in the program
text or a different occurrence) may obtain the same object or a
different object with the same value.


File: python.info,  Node: Parenthesized forms,  Next: Displays for lists sets and dictionaries,  Prev: Literals<2>,  Up: Atoms

4.6.2.4 Parenthesized forms
...........................

A parenthesized form is an optional expression list enclosed in
parentheses:

     parenth_form ::= "(" [*note starred_expression: 21da.] ")"

A parenthesized expression list yields whatever that expression list
yields: if the list contains at least one comma, it yields a tuple;
otherwise, it yields the single expression that makes up the expression
list.

An empty pair of parentheses yields an empty tuple object.  Since tuples
are immutable, the same rules as for literals apply (i.e., two
occurrences of the empty tuple may or may not yield the same object).

Note that tuples are not formed by the parentheses, but rather by use of
the comma.  The exception is the empty tuple, for which parentheses
'are' required — allowing unparenthesized “nothing” in expressions would
cause ambiguities and allow common typos to pass uncaught.


File: python.info,  Node: Displays for lists sets and dictionaries,  Next: List displays,  Prev: Parenthesized forms,  Up: Atoms

4.6.2.5 Displays for lists, sets and dictionaries
.................................................

For constructing a list, a set or a dictionary Python provides special
syntax called “displays”, each of them in two flavors:

   * either the container contents are listed explicitly, or

   * they are computed via a set of looping and filtering instructions,
     called a 'comprehension'.

Common syntax elements for comprehensions are:

     comprehension ::= *note assignment_expression: 2191. *note comp_for: 21dd.
     comp_for      ::= ["async"] "for" *note target_list: 21de. "in" *note or_test: 21df. [*note comp_iter: 21e0.]
     comp_iter     ::= *note comp_for: 21dd. | *note comp_if: 21e1.
     comp_if       ::= "if" *note or_test: 21df. [*note comp_iter: 21e0.]

The comprehension consists of a single expression followed by at least
one ‘for’ clause and zero or more ‘for’ or ‘if’ clauses.  In this case,
the elements of the new container are those that would be produced by
considering each of the ‘for’ or ‘if’ clauses a block, nesting from left
to right, and evaluating the expression to produce an element each time
the innermost block is reached.

However, aside from the iterable expression in the leftmost ‘for’
clause, the comprehension is executed in a separate implicitly nested
scope.  This ensures that names assigned to in the target list don’t
“leak” into the enclosing scope.

The iterable expression in the leftmost ‘for’ clause is evaluated
directly in the enclosing scope and then passed as an argument to the
implicitly nested scope.  Subsequent ‘for’ clauses and any filter
condition in the leftmost ‘for’ clause cannot be evaluated in the
enclosing scope as they may depend on the values obtained from the
leftmost iterable.  For example: ‘[x*y for x in range(10) for y in
range(x, x+10)]’.

To ensure the comprehension always results in a container of the
appropriate type, ‘yield’ and ‘yield from’ expressions are prohibited in
the implicitly nested scope.

Since Python 3.6, in an *note async def: 5d4. function, an ‘async for’
clause may be used to iterate over a *note asynchronous iterator: 1ab.
A comprehension in an ‘async def’ function may consist of either a ‘for’
or ‘async for’ clause following the leading expression, may contain
additional ‘for’ or ‘async for’ clauses, and may also use *note await:
1b9. expressions.

If a comprehension contains ‘async for’ clauses, or if it contains
‘await’ expressions or other asynchronous comprehensions anywhere except
the iterable expression in the leftmost ‘for’ clause, it is called an
'asynchronous comprehension'.  An asynchronous comprehension may suspend
the execution of the coroutine function in which it appears.  See also
PEP 530(1).

Added in version 3.6: Asynchronous comprehensions were introduced.

Changed in version 3.8: ‘yield’ and ‘yield from’ prohibited in the
implicitly nested scope.

Changed in version 3.11: Asynchronous comprehensions are now allowed
inside comprehensions in asynchronous functions.  Outer comprehensions
implicitly become asynchronous.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0530/


File: python.info,  Node: List displays,  Next: Set displays,  Prev: Displays for lists sets and dictionaries,  Up: Atoms

4.6.2.6 List displays
.....................

A list display is a possibly empty series of expressions enclosed in
square brackets:

     list_display ::= "[" [*note flexible_expression_list: 21e4. | *note comprehension: 21dc.] "]"

A list display yields a new list object, the contents being specified by
either a list of expressions or a comprehension.  When a comma-separated
list of expressions is supplied, its elements are evaluated from left to
right and placed into the list object in that order.  When a
comprehension is supplied, the list is constructed from the elements
resulting from the comprehension.


File: python.info,  Node: Set displays,  Next: Dictionary displays,  Prev: List displays,  Up: Atoms

4.6.2.7 Set displays
....................

A set display is denoted by curly braces and distinguishable from
dictionary displays by the lack of colons separating keys and values:

     set_display ::= "{" (*note flexible_expression_list: 21e4. | *note comprehension: 21dc.) "}"

A set display yields a new mutable set object, the contents being
specified by either a sequence of expressions or a comprehension.  When
a comma-separated list of expressions is supplied, its elements are
evaluated from left to right and added to the set object.  When a
comprehension is supplied, the set is constructed from the elements
resulting from the comprehension.

An empty set cannot be constructed with ‘{}’; this literal constructs an
empty dictionary.


File: python.info,  Node: Dictionary displays,  Next: Generator expressions,  Prev: Set displays,  Up: Atoms

4.6.2.8 Dictionary displays
...........................

A dictionary display is a possibly empty series of dict items (key/value
pairs) enclosed in curly braces:

     dict_display       ::= "{" [*note dict_item_list: 21e8. | *note dict_comprehension: 21e9.] "}"
     dict_item_list     ::= *note dict_item: 21ea. ("," *note dict_item: 21ea.)* [","]
     dict_item          ::= *note expression: 21eb. ":" *note expression: 21eb. | "**" *note or_expr: 206f.
     dict_comprehension ::= *note expression: 21eb. ":" *note expression: 21eb. *note comp_for: 21dd.

A dictionary display yields a new dictionary object.

If a comma-separated sequence of dict items is given, they are evaluated
from left to right to define the entries of the dictionary: each key
object is used as a key into the dictionary to store the corresponding
value.  This means that you can specify the same key multiple times in
the dict item list, and the final dictionary’s value for that key will
be the last one given.

A double asterisk ‘**’ denotes 'dictionary unpacking'.  Its operand must
be a *note mapping: 1200.  Each mapping item is added to the new
dictionary.  Later values replace values already set by earlier dict
items and earlier dictionary unpackings.

Added in version 3.5: Unpacking into dictionary displays, originally
proposed by PEP 448(1).

A dict comprehension, in contrast to list and set comprehensions, needs
two expressions separated with a colon followed by the usual “for” and
“if” clauses.  When the comprehension is run, the resulting key and
value elements are inserted in the new dictionary in the order they are
produced.

Restrictions on the types of the key values are listed earlier in
section *note The standard type hierarchy: 2094.  (To summarize, the key
type should be *note hashable: 613, which excludes all mutable objects.)
Clashes between duplicate keys are not detected; the last value
(textually rightmost in the display) stored for a given key value
prevails.

Changed in version 3.8: Prior to Python 3.8, in dict comprehensions, the
evaluation order of key and value was not well-defined.  In CPython, the
value was evaluated before the key.  Starting with 3.8, the key is
evaluated before the value, as proposed by PEP 572(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0448/

   (2) https://peps.python.org/pep-0572/


File: python.info,  Node: Generator expressions,  Next: Yield expressions,  Prev: Dictionary displays,  Up: Atoms

4.6.2.9 Generator expressions
.............................

A generator expression is a compact generator notation in parentheses:

     generator_expression ::= "(" *note expression: 21eb. *note comp_for: 21dd. ")"

A generator expression yields a new generator object.  Its syntax is the
same as for comprehensions, except that it is enclosed in parentheses
instead of brackets or curly braces.

Variables used in the generator expression are evaluated lazily when the
*note __next__(): 1e66. method is called for the generator object (in
the same fashion as normal generators).  However, the iterable
expression in the leftmost ‘for’ clause is immediately evaluated, and
the *note iterator: 1ac. is immediately created for that iterable, so
that an error produced while creating the iterator will be emitted at
the point where the generator expression is defined, rather than at the
point where the first value is retrieved.  Subsequent ‘for’ clauses and
any filter condition in the leftmost ‘for’ clause cannot be evaluated in
the enclosing scope as they may depend on the values obtained from the
leftmost iterable.  For example: ‘(x*y for x in range(10) for y in
range(x, x+10))’.

The parentheses can be omitted on calls with only one argument.  See
section *note Calls: dab. for details.

To avoid interfering with the expected operation of the generator
expression itself, ‘yield’ and ‘yield from’ expressions are prohibited
in the implicitly defined generator.

If a generator expression contains either ‘async for’ clauses or *note
await: 1b9. expressions it is called an 'asynchronous generator
expression'.  An asynchronous generator expression returns a new
asynchronous generator object, which is an asynchronous iterator (see
*note Asynchronous Iterators: da5.).

Added in version 3.6: Asynchronous generator expressions were
introduced.

Changed in version 3.7: Prior to Python 3.7, asynchronous generator
expressions could only appear in *note async def: 5d4. coroutines.
Starting with 3.7, any function can use asynchronous generator
expressions.

Changed in version 3.8: ‘yield’ and ‘yield from’ prohibited in the
implicitly nested scope.


File: python.info,  Node: Yield expressions,  Prev: Generator expressions,  Up: Atoms

4.6.2.10 Yield expressions
..........................

     yield_atom       ::= "(" *note yield_expression: 2070. ")"
     yield_from       ::= "yield" "from" *note expression: 21eb.
     yield_expression ::= "yield" *note yield_list: 21f1. | *note yield_from: 21f0.

The yield expression is used when defining a *note generator: 109f.
function or an *note asynchronous generator: 21f2. function and thus can
only be used in the body of a function definition.  Using a yield
expression in a function’s body causes that function to be a generator
function, and using it in an *note async def: 5d4. function’s body
causes that coroutine function to be an asynchronous generator function.
For example:

     def gen():  # defines a generator function
         yield 123

     async def agen(): # defines an asynchronous generator function
         yield 123

Due to their side effects on the containing scope, ‘yield’ expressions
are not permitted as part of the implicitly defined scopes used to
implement comprehensions and generator expressions.

Changed in version 3.8: Yield expressions prohibited in the implicitly
nested scopes used to implement comprehensions and generator
expressions.

Generator functions are described below, while asynchronous generator
functions are described separately in section *note Asynchronous
generator functions: 21f3.

When a generator function is called, it returns an iterator known as a
generator.  That generator then controls the execution of the generator
function.  The execution starts when one of the generator’s methods is
called.  At that time, the execution proceeds to the first yield
expression, where it is suspended again, returning the value of *note
yield_list: 21f1. to the generator’s caller, or ‘None’ if ‘yield_list’
is omitted.  By suspended, we mean that all local state is retained,
including the current bindings of local variables, the instruction
pointer, the internal evaluation stack, and the state of any exception
handling.  When the execution is resumed by calling one of the
generator’s methods, the function can proceed exactly as if the yield
expression were just another external call.  The value of the yield
expression after resuming depends on the method which resumed the
execution.  If *note __next__(): 1e66. is used (typically via either a
*note for: 2f2. or the *note next(): 7dc. builtin) then the result is
*note None: 678.  Otherwise, if *note send(): 217d. is used, then the
result will be the value passed in to that method.

All of this makes generator functions quite similar to coroutines; they
yield multiple times, they have more than one entry point and their
execution can be suspended.  The only difference is that a generator
function cannot control where the execution should continue after it
yields; the control is always transferred to the generator’s caller.

Yield expressions are allowed anywhere in a *note try: 6ec. construct.
If the generator is not resumed before it is finalized (by reaching a
zero reference count or by being garbage collected), the
generator-iterator’s *note close(): 15df. method will be called,
allowing any pending *note finally: 9d5. clauses to execute.

When ‘yield from <expr>’ is used, the supplied expression must be an
iterable.  The values produced by iterating that iterable are passed
directly to the caller of the current generator’s methods.  Any values
passed in with *note send(): 217d. and any exceptions passed in with
*note throw(): 4fb. are passed to the underlying iterator if it has the
appropriate methods.  If this is not the case, then ‘send()’ will raise
*note AttributeError: 34e. or *note TypeError: 2c3, while ‘throw()’ will
just raise the passed in exception immediately.

When the underlying iterator is complete, the *note value: 217a.
attribute of the raised *note StopIteration: c1b. instance becomes the
value of the yield expression.  It can be either set explicitly when
raising ‘StopIteration’, or automatically when the subiterator is a
generator (by returning a value from the subgenerator).

Changed in version 3.3: Added ‘yield from <expr>’ to delegate control
flow to a subiterator.

The parentheses may be omitted when the yield expression is the sole
expression on the right hand side of an assignment statement.

See also
........

PEP 255(1) - Simple Generators

     The proposal for adding generators and the *note yield: 9d8.
     statement to Python.

PEP 342(2) - Coroutines via Enhanced Generators

     The proposal to enhance the API and syntax of generators, making
     them usable as simple coroutines.

PEP 380(3) - Syntax for Delegating to a Subgenerator

     The proposal to introduce the *note yield_from: 21f0. syntax,
     making delegation to subgenerators easy.

PEP 525(4) - Asynchronous Generators

     The proposal that expanded on PEP 492(5) by adding generator
     capabilities to coroutine functions.

* Menu:

* Generator-iterator methods::
* Examples::
* Asynchronous generator functions: Asynchronous generator functions<2>.
* Asynchronous generator-iterator methods::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0255/

   (2) https://peps.python.org/pep-0342/

   (3) https://peps.python.org/pep-0380/

   (4) https://peps.python.org/pep-0525/

   (5) https://peps.python.org/pep-0492/


File: python.info,  Node: Generator-iterator methods,  Next: Examples,  Up: Yield expressions

4.6.2.11 Generator-iterator methods
...................................

This subsection describes the methods of a generator iterator.  They can
be used to control the execution of a generator function.

Note that calling any of the generator methods below when the generator
is already executing raises a *note ValueError: 202. exception.

 -- Method: generator.__next__ ()

     Starts the execution of a generator function or resumes it at the
     last executed yield expression.  When a generator function is
     resumed with a ‘__next__()’ method, the current yield expression
     always evaluates to *note None: 678.  The execution then continues
     to the next yield expression, where the generator is suspended
     again, and the value of the *note yield_list: 21f1. is returned to
     ‘__next__()’’s caller.  If the generator exits without yielding
     another value, a *note StopIteration: c1b. exception is raised.

     This method is normally called implicitly, e.g.  by a *note for:
     2f2. loop, or by the built-in *note next(): 7dc. function.

 -- Method: generator.send (value)

     Resumes the execution and “sends” a value into the generator
     function.  The 'value' argument becomes the result of the current
     yield expression.  The ‘send()’ method returns the next value
     yielded by the generator, or raises *note StopIteration: c1b. if
     the generator exits without yielding another value.  When ‘send()’
     is called to start the generator, it must be called with *note
     None: 678. as the argument, because there is no yield expression
     that could receive the value.

 -- Method: generator.throw (value)

 -- Method: generator.throw (type[, value[, traceback]])

     Raises an exception at the point where the generator was paused,
     and returns the next value yielded by the generator function.  If
     the generator exits without yielding another value, a *note
     StopIteration: c1b. exception is raised.  If the generator function
     does not catch the passed-in exception, or raises a different
     exception, then that exception propagates to the caller.

     In typical use, this is called with a single exception instance
     similar to the way the *note raise: 5f0. keyword is used.

     For backwards compatibility, however, the second signature is
     supported, following a convention from older versions of Python.
     The 'type' argument should be an exception class, and 'value'
     should be an exception instance.  If the 'value' is not provided,
     the 'type' constructor is called to get an instance.  If
     'traceback' is provided, it is set on the exception, otherwise any
     existing *note __traceback__: 130e. attribute stored in 'value' may
     be cleared.

     Changed in version 3.12: The second signature (type[, value[,
     traceback]]) is deprecated and may be removed in a future version
     of Python.

 -- Method: generator.close ()

     Raises a *note GeneratorExit: 1414. exception at the point where
     the generator function was paused (equivalent to calling
     ‘throw(GeneratorExit)’).  The exception is raised by the yield
     expression where the generator was paused.  If the generator
     function catches the exception and returns a value, this value is
     returned from ‘close()’.  If the generator function is already
     closed, or raises ‘GeneratorExit’ (by not catching the exception),
     ‘close()’ returns *note None: 678.  If the generator yields a
     value, a *note RuntimeError: 195. is raised.  If the generator
     raises any other exception, it is propagated to the caller.  If the
     generator has already exited due to an exception or normal exit,
     ‘close()’ returns ‘None’ and has no other effect.

     Changed in version 3.13: If a generator returns a value upon being
     closed, the value is returned by ‘close()’.


File: python.info,  Node: Examples,  Next: Asynchronous generator functions<2>,  Prev: Generator-iterator methods,  Up: Yield expressions

4.6.2.12 Examples
.................

Here is a simple example that demonstrates the behavior of generators
and generator functions:

     >>> def echo(value=None):
     ...     print("Execution starts when 'next()' is called for the first time.")
     ...     try:
     ...         while True:
     ...             try:
     ...                 value = (yield value)
     ...             except Exception as e:
     ...                 value = e
     ...     finally:
     ...         print("Don't forget to clean up when 'close()' is called.")
     ...
     >>> generator = echo(1)
     >>> print(next(generator))
     Execution starts when 'next()' is called for the first time.
     1
     >>> print(next(generator))
     None
     >>> print(generator.send(2))
     2
     >>> generator.throw(TypeError, "spam")
     TypeError('spam',)
     >>> generator.close()
     Don't forget to clean up when 'close()' is called.

For examples using ‘yield from’, see *note PEP 380; Syntax for
Delegating to a Subgenerator: 1077. in “What’s New in Python.”


File: python.info,  Node: Asynchronous generator functions<2>,  Next: Asynchronous generator-iterator methods,  Prev: Examples,  Up: Yield expressions

4.6.2.13 Asynchronous generator functions
.........................................

The presence of a yield expression in a function or method defined using
*note async def: 5d4. further defines the function as an *note
asynchronous generator: 21f2. function.

When an asynchronous generator function is called, it returns an
asynchronous iterator known as an asynchronous generator object.  That
object then controls the execution of the generator function.  An
asynchronous generator object is typically used in an *note async for:
ac0. statement in a coroutine function analogously to how a generator
object would be used in a *note for: 2f2. statement.

Calling one of the asynchronous generator’s methods returns an *note
awaitable: 1ad. object, and the execution starts when this object is
awaited on.  At that time, the execution proceeds to the first yield
expression, where it is suspended again, returning the value of *note
yield_list: 21f1. to the awaiting coroutine.  As with a generator,
suspension means that all local state is retained, including the current
bindings of local variables, the instruction pointer, the internal
evaluation stack, and the state of any exception handling.  When the
execution is resumed by awaiting on the next object returned by the
asynchronous generator’s methods, the function can proceed exactly as if
the yield expression were just another external call.  The value of the
yield expression after resuming depends on the method which resumed the
execution.  If *note __anext__(): 21f7. is used then the result is *note
None: 678.  Otherwise, if *note asend(): 8e2. is used, then the result
will be the value passed in to that method.

If an asynchronous generator happens to exit early by *note break: abe,
the caller task being cancelled, or other exceptions, the generator’s
async cleanup code will run and possibly raise exceptions or access
context variables in an unexpected context–perhaps after the lifetime of
tasks it depends, or during the event loop shutdown when the
async-generator garbage collection hook is called.  To prevent this, the
caller must explicitly close the async generator by calling *note
aclose(): 8e1. method to finalize the generator and ultimately detach it
from the event loop.

In an asynchronous generator function, yield expressions are allowed
anywhere in a *note try: 6ec. construct.  However, if an asynchronous
generator is not resumed before it is finalized (by reaching a zero
reference count or by being garbage collected), then a yield expression
within a ‘try’ construct could result in a failure to execute pending
*note finally: 9d5. clauses.  In this case, it is the responsibility of
the event loop or scheduler running the asynchronous generator to call
the asynchronous generator-iterator’s *note aclose(): 8e1. method and
run the resulting coroutine object, thus allowing any pending ‘finally’
clauses to execute.

To take care of finalization upon event loop termination, an event loop
should define a 'finalizer' function which takes an asynchronous
generator-iterator and presumably calls *note aclose(): 8e1. and
executes the coroutine.  This 'finalizer' may be registered by calling
*note sys.set_asyncgen_hooks(): 1730.  When first iterated over, an
asynchronous generator-iterator will store the registered 'finalizer' to
be called upon finalization.  For a reference example of a 'finalizer'
method see the implementation of ‘asyncio.Loop.shutdown_asyncgens’ in
Lib/asyncio/base_events.py(1).

The expression ‘yield from <expr>’ is a syntax error when used in an
asynchronous generator function.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/base_events.py


File: python.info,  Node: Asynchronous generator-iterator methods,  Prev: Asynchronous generator functions<2>,  Up: Yield expressions

4.6.2.14 Asynchronous generator-iterator methods
................................................

This subsection describes the methods of an asynchronous generator
iterator, which are used to control the execution of a generator
function.

 -- Method: async agen.__anext__ ()

     Returns an awaitable which when run starts to execute the
     asynchronous generator or resumes it at the last executed yield
     expression.  When an asynchronous generator function is resumed
     with an ‘__anext__()’ method, the current yield expression always
     evaluates to *note None: 678. in the returned awaitable, which when
     run will continue to the next yield expression.  The value of the
     *note yield_list: 21f1. of the yield expression is the value of the
     *note StopIteration: c1b. exception raised by the completing
     coroutine.  If the asynchronous generator exits without yielding
     another value, the awaitable instead raises a *note
     StopAsyncIteration: 1bbe. exception, signalling that the
     asynchronous iteration has completed.

     This method is normally called implicitly by a *note async for:
     ac0. loop.

 -- Method: async agen.asend (value)

     Returns an awaitable which when run resumes the execution of the
     asynchronous generator.  As with the *note send(): 217d. method for
     a generator, this “sends” a value into the asynchronous generator
     function, and the 'value' argument becomes the result of the
     current yield expression.  The awaitable returned by the ‘asend()’
     method will return the next value yielded by the generator as the
     value of the raised *note StopIteration: c1b, or raises *note
     StopAsyncIteration: 1bbe. if the asynchronous generator exits
     without yielding another value.  When ‘asend()’ is called to start
     the asynchronous generator, it must be called with *note None: 678.
     as the argument, because there is no yield expression that could
     receive the value.

 -- Method: async agen.athrow (value)

 -- Method: async agen.athrow (type[, value[, traceback]])

     Returns an awaitable that raises an exception of type ‘type’ at the
     point where the asynchronous generator was paused, and returns the
     next value yielded by the generator function as the value of the
     raised *note StopIteration: c1b. exception.  If the asynchronous
     generator exits without yielding another value, a *note
     StopAsyncIteration: 1bbe. exception is raised by the awaitable.  If
     the generator function does not catch the passed-in exception, or
     raises a different exception, then when the awaitable is run that
     exception propagates to the caller of the awaitable.

     Changed in version 3.12: The second signature (type[, value[,
     traceback]]) is deprecated and may be removed in a future version
     of Python.

 -- Method: async agen.aclose ()

     Returns an awaitable that when run will throw a *note
     GeneratorExit: 1414. into the asynchronous generator function at
     the point where it was paused.  If the asynchronous generator
     function then exits gracefully, is already closed, or raises
     ‘GeneratorExit’ (by not catching the exception), then the returned
     awaitable will raise a *note StopIteration: c1b. exception.  Any
     further awaitables returned by subsequent calls to the asynchronous
     generator will raise a *note StopAsyncIteration: 1bbe. exception.
     If the asynchronous generator yields a value, a *note RuntimeError:
     195. is raised by the awaitable.  If the asynchronous generator
     raises any other exception, it is propagated to the caller of the
     awaitable.  If the asynchronous generator has already exited due to
     an exception or normal exit, then further calls to ‘aclose()’ will
     return an awaitable that does nothing.


File: python.info,  Node: Primaries,  Next: Await expression,  Prev: Atoms,  Up: Expressions

4.6.3 Primaries
---------------

Primaries represent the most tightly bound operations of the language.
Their syntax is:

     primary ::= *note atom: 21cb. | *note attributeref: 21fd. | *note subscription: 21fe. | *note slicing: 21ff. | *note call: 2200.

* Menu:

* Attribute references::
* Subscriptions::
* Slicings::
* Calls::


File: python.info,  Node: Attribute references,  Next: Subscriptions,  Up: Primaries

4.6.3.1 Attribute references
............................

An attribute reference is a primary followed by a period and a name:

     attributeref ::= *note primary: 21fc. "." *note identifier: 2042.

The primary must evaluate to an object of a type that supports attribute
references, which most objects do.  This object is then asked to produce
the attribute whose name is the identifier.  The type and value produced
is determined by the object.  Multiple evaluations of the same attribute
reference may yield different objects.

This production can be customized by overriding the *note
__getattribute__(): bf1. method or the *note __getattr__(): 4d6. method.
The ‘__getattribute__()’ method is called first and either returns a
value or raises *note AttributeError: 34e. if the attribute is not
available.

If an *note AttributeError: 34e. is raised and the object has a
‘__getattr__()’ method, that method is called as a fallback.


File: python.info,  Node: Subscriptions,  Next: Slicings,  Prev: Attribute references,  Up: Primaries

4.6.3.2 Subscriptions
.....................

The subscription of an instance of a *note container class: 213a. will
generally select an element from the container.  The subscription of a
*note generic class: 43c. will generally return a *note GenericAlias:
6b5. object.

     subscription ::= *note primary: 21fc. "[" *note flexible_expression_list: 21e4. "]"

When an object is subscripted, the interpreter will evaluate the primary
and the expression list.

The primary must evaluate to an object that supports subscription.  An
object may support subscription through defining one or both of *note
__getitem__(): 283. and *note __class_getitem__(): 73e.  When the
primary is subscripted, the evaluated result of the expression list will
be passed to one of these methods.  For more details on when
‘__class_getitem__’ is called instead of ‘__getitem__’, see *note
__class_getitem__ versus __getitem__: 2133.

If the expression list contains at least one comma, or if any of the
expressions are starred, the expression list will evaluate to a *note
tuple: 373. containing the items of the expression list.  Otherwise, the
expression list will evaluate to the value of the list’s sole member.

Changed in version 3.11: Expressions in an expression list may be
starred.  See PEP 646(1).

For built-in objects, there are two types of objects that support
subscription via *note __getitem__(): 283.:

  1. Mappings.  If the primary is a *note mapping: 1200, the expression
     list must evaluate to an object whose value is one of the keys of
     the mapping, and the subscription selects the value in the mapping
     that corresponds to that key.  An example of a builtin mapping
     class is the *note dict: 256. class.

  2. Sequences.  If the primary is a *note sequence: 4f4, the expression
     list must evaluate to an *note int: 257. or a *note slice: 46c. (as
     discussed in the following section).  Examples of builtin sequence
     classes include the *note str: 44f, *note list: 614. and *note
     tuple: 373. classes.

The formal syntax makes no special provision for negative indices in
*note sequences: 4f4.  However, built-in sequences all provide a *note
__getitem__(): 283. method that interprets negative indices by adding
the length of the sequence to the index so that, for example, ‘x[-1]’
selects the last item of ‘x’.  The resulting value must be a nonnegative
integer less than the number of items in the sequence, and the
subscription selects the item whose index is that value (counting from
zero).  Since the support for negative indices and slicing occurs in the
object’s ‘__getitem__()’ method, subclasses overriding this method will
need to explicitly add that support.

A *note string: 44f. is a special kind of sequence whose items are
'characters'.  A character is not a separate data type but a string of
exactly one character.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0646/


File: python.info,  Node: Slicings,  Next: Calls,  Prev: Subscriptions,  Up: Primaries

4.6.3.3 Slicings
................

A slicing selects a range of items in a sequence object (e.g., a string,
tuple or list).  Slicings may be used as expressions or as targets in
assignment or *note del: 18c2. statements.  The syntax for a slicing:

     slicing      ::= *note primary: 21fc. "[" *note slice_list: 2206. "]"
     slice_list   ::= *note slice_item: 2207. ("," *note slice_item: 2207.)* [","]
     slice_item   ::= *note expression: 21eb. | *note proper_slice: 2208.
     proper_slice ::= [*note lower_bound: 2209.] ":" [*note upper_bound: 220a.] [ ":" [*note stride: 220b.] ]
     lower_bound  ::= *note expression: 21eb.
     upper_bound  ::= *note expression: 21eb.
     stride       ::= *note expression: 21eb.

There is ambiguity in the formal syntax here: anything that looks like
an expression list also looks like a slice list, so any subscription can
be interpreted as a slicing.  Rather than further complicating the
syntax, this is disambiguated by defining that in this case the
interpretation as a subscription takes priority over the interpretation
as a slicing (this is the case if the slice list contains no proper
slice).

The semantics for a slicing are as follows.  The primary is indexed
(using the same *note __getitem__(): 283. method as normal subscription)
with a key that is constructed from the slice list, as follows.  If the
slice list contains at least one comma, the key is a tuple containing
the conversion of the slice items; otherwise, the conversion of the lone
slice item is the key.  The conversion of a slice item that is an
expression is that expression.  The conversion of a proper slice is a
slice object (see section *note The standard type hierarchy: 2094.)
whose *note start: 210b, *note stop: 210c. and *note step: 210d.
attributes are the values of the expressions given as lower bound, upper
bound and stride, respectively, substituting ‘None’ for missing
expressions.


File: python.info,  Node: Calls,  Prev: Slicings,  Up: Primaries

4.6.3.4 Calls
.............

A call calls a callable object (e.g., a *note function: 220d.) with a
possibly empty series of *note arguments: 44c.:

     call                 ::= *note primary: 21fc. "(" [*note argument_list: 220e. [","] | *note comprehension: 21dc.] ")"
     argument_list        ::= *note positional_arguments: 220f. ["," *note starred_and_keywords: 2210.]
                              ["," *note keywords_arguments: 2211.]
                              | *note starred_and_keywords: 2210. ["," *note keywords_arguments: 2211.]
                              | *note keywords_arguments: 2211.
     positional_arguments ::= *note positional_item: 2212. ("," *note positional_item: 2212.)*
     positional_item      ::= *note assignment_expression: 2191. | "*" *note expression: 21eb.
     starred_and_keywords ::= ("*" *note expression: 21eb. | *note keyword_item: 2213.)
                              ("," "*" *note expression: 21eb. | "," *note keyword_item: 2213.)*
     keywords_arguments   ::= (*note keyword_item: 2213. | "**" *note expression: 21eb.)
                              ("," *note keyword_item: 2213. | "," "**" *note expression: 21eb.)*
     keyword_item         ::= *note identifier: 2042. "=" *note expression: 21eb.

An optional trailing comma may be present after the positional and
keyword arguments but does not affect the semantics.

The primary must evaluate to a callable object (user-defined functions,
built-in functions, methods of built-in objects, class objects, methods
of class instances, and all objects having a *note __call__(): 55b.
method are callable).  All argument expressions are evaluated before the
call is attempted.  Please refer to section *note Function definitions:
1dce. for the syntax of formal *note parameter: 20ae. lists.

If keyword arguments are present, they are first converted to positional
arguments, as follows.  First, a list of unfilled slots is created for
the formal parameters.  If there are N positional arguments, they are
placed in the first N slots.  Next, for each keyword argument, the
identifier is used to determine the corresponding slot (if the
identifier is the same as the first formal parameter name, the first
slot is used, and so on).  If the slot is already filled, a *note
TypeError: 2c3. exception is raised.  Otherwise, the argument is placed
in the slot, filling it (even if the expression is ‘None’, it fills the
slot).  When all arguments have been processed, the slots that are still
unfilled are filled with the corresponding default value from the
function definition.  (Default values are calculated, once, when the
function is defined; thus, a mutable object such as a list or dictionary
used as default value will be shared by all calls that don’t specify an
argument value for the corresponding slot; this should usually be
avoided.)  If there are any unfilled slots for which no default value is
specified, a ‘TypeError’ exception is raised.  Otherwise, the list of
filled slots is used as the argument list for the call.

'CPython implementation detail:' An implementation may provide built-in
functions whose positional parameters do not have names, even if they
are ‘named’ for the purpose of documentation, and which therefore cannot
be supplied by keyword.  In CPython, this is the case for functions
implemented in C that use *note PyArg_ParseTuple(): 574. to parse their
arguments.

If there are more positional arguments than there are formal parameter
slots, a *note TypeError: 2c3. exception is raised, unless a formal
parameter using the syntax ‘*identifier’ is present; in this case, that
formal parameter receives a tuple containing the excess positional
arguments (or an empty tuple if there were no excess positional
arguments).

If any keyword argument does not correspond to a formal parameter name,
a *note TypeError: 2c3. exception is raised, unless a formal parameter
using the syntax ‘**identifier’ is present; in this case, that formal
parameter receives a dictionary containing the excess keyword arguments
(using the keywords as keys and the argument values as corresponding
values), or a (new) empty dictionary if there were no excess keyword
arguments.

If the syntax ‘*expression’ appears in the function call, ‘expression’
must evaluate to an *note iterable: 126d.  Elements from these iterables
are treated as if they were additional positional arguments.  For the
call ‘f(x1, x2, *y, x3, x4)’, if 'y' evaluates to a sequence 'y1', …,
'yM', this is equivalent to a call with M+4 positional arguments 'x1',
'x2', 'y1', …, 'yM', 'x3', 'x4'.

A consequence of this is that although the ‘*expression’ syntax may
appear 'after' explicit keyword arguments, it is processed 'before' the
keyword arguments (and any ‘**expression’ arguments – see below).  So:

     >>> def f(a, b):
     ...     print(a, b)
     ...
     >>> f(b=1, *(2,))
     2 1
     >>> f(a=1, *(2,))
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: f() got multiple values for keyword argument 'a'
     >>> f(1, *(2,))
     1 2

It is unusual for both keyword arguments and the ‘*expression’ syntax to
be used in the same call, so in practice this confusion does not often
arise.

If the syntax ‘**expression’ appears in the function call, ‘expression’
must evaluate to a *note mapping: 1200, the contents of which are
treated as additional keyword arguments.  If a parameter matching a key
has already been given a value (by an explicit keyword argument, or from
another unpacking), a *note TypeError: 2c3. exception is raised.

When ‘**expression’ is used, each key in this mapping must be a string.
Each value from the mapping is assigned to the first formal parameter
eligible for keyword assignment whose name is equal to the key.  A key
need not be a Python identifier (e.g.  ‘"max-temp °F"’ is acceptable,
although it will not match any formal parameter that could be declared).
If there is no match to a formal parameter the key-value pair is
collected by the ‘**’ parameter, if there is one, or if there is not, a
*note TypeError: 2c3. exception is raised.

Formal parameters using the syntax ‘*identifier’ or ‘**identifier’
cannot be used as positional argument slots or as keyword argument
names.

Changed in version 3.5: Function calls accept any number of ‘*’ and ‘**’
unpackings, positional arguments may follow iterable unpackings (‘*’),
and keyword arguments may follow dictionary unpackings (‘**’).
Originally proposed by PEP 448(1).

A call always returns some value, possibly ‘None’, unless it raises an
exception.  How this value is computed depends on the type of the
callable object.

If it is—

a user-defined function:

     The code block for the function is executed, passing it the
     argument list.  The first thing the code block will do is bind the
     formal parameters to the arguments; this is described in section
     *note Function definitions: 1dce.  When the code block executes a
     *note return: 9d9. statement, this specifies the return value of
     the function call.  If execution reaches the end of the code block
     without executing a ‘return’ statement, the return value is ‘None’.

a built-in function or method:

     The result is up to the interpreter; see *note Built-in Functions:
     12a3. for the descriptions of built-in functions and methods.

a class object:

     A new instance of that class is returned.

a class instance method:

     The corresponding user-defined function is called, with an argument
     list that is one longer than the argument list of the call: the
     instance becomes the first argument.

a class instance:

     The class must define a *note __call__(): 55b. method; the effect
     is then the same as if that method was called.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0448/


File: python.info,  Node: Await expression,  Next: The power operator,  Prev: Primaries,  Up: Expressions

4.6.4 Await expression
----------------------

Suspend the execution of *note coroutine: 494. on an *note awaitable:
1ad. object.  Can only be used inside a *note coroutine function: da1.

     await_expr ::= "await" *note primary: 21fc.

Added in version 3.5.


File: python.info,  Node: The power operator,  Next: Unary arithmetic and bitwise operations,  Prev: Await expression,  Up: Expressions

4.6.5 The power operator
------------------------

The power operator binds more tightly than unary operators on its left;
it binds less tightly than unary operators on its right.  The syntax is:

     power ::= (*note await_expr: 2215. | *note primary: 21fc.) ["**" *note u_expr: 2219.]

Thus, in an unparenthesized sequence of power and unary operators, the
operators are evaluated from right to left (this does not constrain the
evaluation order for the operands): ‘-1**2’ results in ‘-1’.

The power operator has the same semantics as the built-in *note pow():
9dd. function, when called with two arguments: it yields its left
argument raised to the power of its right argument.  The numeric
arguments are first converted to a common type, and the result is of
that type.

For int operands, the result has the same type as the operands unless
the second argument is negative; in that case, all arguments are
converted to float and a float result is delivered.  For example,
‘10**2’ returns ‘100’, but ‘10**-2’ returns ‘0.01’.

Raising ‘0.0’ to a negative power results in a *note ZeroDivisionError:
94f.  Raising a negative number to a fractional power results in a *note
complex: 2f8. number.  (In earlier versions it raised a *note
ValueError: 202.)

This operation can be customized using the special *note __pow__(): 7d7.
and *note __rpow__(): 7d8. methods.


File: python.info,  Node: Unary arithmetic and bitwise operations,  Next: Binary arithmetic operations,  Prev: The power operator,  Up: Expressions

4.6.6 Unary arithmetic and bitwise operations
---------------------------------------------

All unary arithmetic and bitwise operations have the same priority:

     u_expr ::= *note power: 2218. | "-" *note u_expr: 2219. | "+" *note u_expr: 2219. | "~" *note u_expr: 2219.

The unary ‘-’ (minus) operator yields the negation of its numeric
argument; the operation can be overridden with the *note __neg__():
2168. special method.

The unary ‘+’ (plus) operator yields its numeric argument unchanged; the
operation can be overridden with the *note __pos__(): 2169. special
method.

The unary ‘~’ (invert) operator yields the bitwise inversion of its
integer argument.  The bitwise inversion of ‘x’ is defined as ‘-(x+1)’.
It only applies to integral numbers or to custom objects that override
the *note __invert__(): 216b. special method.

In all three cases, if the argument does not have the proper type, a
*note TypeError: 2c3. exception is raised.


File: python.info,  Node: Binary arithmetic operations,  Next: Shifting operations,  Prev: Unary arithmetic and bitwise operations,  Up: Expressions

4.6.7 Binary arithmetic operations
----------------------------------

The binary arithmetic operations have the conventional priority levels.
Note that some of these operations also apply to certain non-numeric
types.  Apart from the power operator, there are only two levels, one
for multiplicative operators and one for additive operators:

     m_expr ::= *note u_expr: 2219. | *note m_expr: 221e. "*" *note u_expr: 2219. | *note m_expr: 221e. "@" *note m_expr: 221e. |
                *note m_expr: 221e. "//" *note u_expr: 2219. | *note m_expr: 221e. "/" *note u_expr: 2219. |
                *note m_expr: 221e. "%" *note u_expr: 2219.
     a_expr ::= *note m_expr: 221e. | *note a_expr: 221f. "+" *note m_expr: 221e. | *note a_expr: 221f. "-" *note m_expr: 221e.

The ‘*’ (multiplication) operator yields the product of its arguments.
The arguments must either both be numbers, or one argument must be an
integer and the other must be a sequence.  In the former case, the
numbers are converted to a common type and then multiplied together.  In
the latter case, sequence repetition is performed; a negative repetition
factor yields an empty sequence.

This operation can be customized using the special *note __mul__():
2148. and *note __rmul__(): 2149. methods.

The ‘@’ (at) operator is intended to be used for matrix multiplication.
No builtin Python types implement this operator.

This operation can be customized using the special *note __matmul__():
da7. and *note __rmatmul__(): da8. methods.

Added in version 3.5.

The ‘/’ (division) and ‘//’ (floor division) operators yield the
quotient of their arguments.  The numeric arguments are first converted
to a common type.  Division of integers yields a float, while floor
division of integers results in an integer; the result is that of
mathematical division with the ‘floor’ function applied to the result.
Division by zero raises the *note ZeroDivisionError: 94f. exception.

The division operation can be customized using the special *note
__truediv__(): ec4. and *note __rtruediv__(): 2156. methods.  The floor
division operation can be customized using the special *note
__floordiv__(): 1543. and *note __rfloordiv__(): 2157. methods.

The ‘%’ (modulo) operator yields the remainder from the division of the
first argument by the second.  The numeric arguments are first converted
to a common type.  A zero right argument raises the *note
ZeroDivisionError: 94f. exception.  The arguments may be floating-point
numbers, e.g., ‘3.14%0.7’ equals ‘0.34’ (since ‘3.14’ equals ‘4*0.7 +
0.34’.)  The modulo operator always yields a result with the same sign
as its second operand (or zero); the absolute value of the result is
strictly smaller than the absolute value of the second operand (1).

The floor division and modulo operators are connected by the following
identity: ‘x == (x//y)*y + (x%y)’.  Floor division and modulo are also
connected with the built-in function *note divmod(): 9ac.: ‘divmod(x, y)
== (x//y, x%y)’.  (2).

In addition to performing the modulo operation on numbers, the ‘%’
operator is also overloaded by string objects to perform old-style
string formatting (also known as interpolation).  The syntax for string
formatting is described in the Python Library Reference, section *note
printf-style String Formatting: 6cf.

The 'modulo' operation can be customized using the special *note
__mod__(): 214f. and *note __rmod__(): e05. methods.

The floor division operator, the modulo operator, and the *note
divmod(): 9ac. function are not defined for complex numbers.  Instead,
convert to a floating-point number using the *note abs(): 1e45. function
if appropriate.

The ‘+’ (addition) operator yields the sum of its arguments.  The
arguments must either both be numbers or both be sequences of the same
type.  In the former case, the numbers are converted to a common type
and then added together.  In the latter case, the sequences are
concatenated.

This operation can be customized using the special *note __add__():
2145. and *note __radd__(): 2146. methods.

The ‘-’ (subtraction) operator yields the difference of its arguments.
The numeric arguments are first converted to a common type.

This operation can be customized using the special *note __sub__():
214e. and *note __rsub__(): 2155. methods.

   ---------- Footnotes ----------

   (1) While ‘abs(x%y) < abs(y)’ is true mathematically, for floats it
may not be true numerically due to roundoff.  For example, and assuming
a platform on which a Python float is an IEEE 754 double-precision
number, in order that ‘-1e-100 % 1e100’ have the same sign as ‘1e100’,
the computed result is ‘-1e-100 + 1e100’, which is numerically exactly
equal to ‘1e100’.  The function *note math.fmod(): 2220. returns a
result whose sign matches the sign of the first argument instead, and so
returns ‘-1e-100’ in this case.  Which approach is more appropriate
depends on the application.

   (2) If x is very close to an exact integer multiple of y, it’s
possible for ‘x//y’ to be one larger than ‘(x-x%y)//y’ due to rounding.
In such cases, Python returns the latter result, in order to preserve
that ‘divmod(x,y)[0] * y + x % y’ be very close to ‘x’.


File: python.info,  Node: Shifting operations,  Next: Binary bitwise operations,  Prev: Binary arithmetic operations,  Up: Expressions

4.6.8 Shifting operations
-------------------------

The shifting operations have lower priority than the arithmetic
operations:

     shift_expr ::= *note a_expr: 221f. | *note shift_expr: 2223. ("<<" | ">>") *note a_expr: 221f.

These operators accept integers as arguments.  They shift the first
argument to the left or right by the number of bits given by the second
argument.

The left shift operation can be customized using the special *note
__lshift__(): 2150. and *note __rlshift__(): 2159. methods.  The right
shift operation can be customized using the special *note __rshift__():
2151. and *note __rrshift__(): 215a. methods.

A right shift by 'n' bits is defined as floor division by ‘pow(2,n)’.  A
left shift by 'n' bits is defined as multiplication with ‘pow(2,n)’.


File: python.info,  Node: Binary bitwise operations,  Next: Comparisons,  Prev: Shifting operations,  Up: Expressions

4.6.9 Binary bitwise operations
-------------------------------

Each of the three bitwise operations has a different priority level:

     and_expr ::= *note shift_expr: 2223. | *note and_expr: 2226. "&" *note shift_expr: 2223.
     xor_expr ::= *note and_expr: 2226. | *note xor_expr: 2227. "^" *note and_expr: 2226.
     or_expr  ::= *note xor_expr: 2227. | *note or_expr: 206f. "|" *note xor_expr: 2227.

The ‘&’ operator yields the bitwise AND of its arguments, which must be
integers or one of them must be a custom object overriding *note
__and__(): 2152. or *note __rand__(): 215b. special methods.

The ‘^’ operator yields the bitwise XOR (exclusive OR) of its arguments,
which must be integers or one of them must be a custom object overriding
*note __xor__(): 2153. or *note __rxor__(): 215c. special methods.

The ‘|’ operator yields the bitwise (inclusive) OR of its arguments,
which must be integers or one of them must be a custom object overriding
*note __or__(): 2154. or *note __ror__(): 215d. special methods.


File: python.info,  Node: Comparisons,  Next: Boolean operations,  Prev: Binary bitwise operations,  Up: Expressions

4.6.10 Comparisons
------------------

Unlike C, all comparison operations in Python have the same priority,
which is lower than that of any arithmetic, shifting or bitwise
operation.  Also unlike C, expressions like ‘a < b < c’ have the
interpretation that is conventional in mathematics:

     comparison    ::= *note or_expr: 206f. (*note comp_operator: 222b. *note or_expr: 206f.)*
     comp_operator ::= "<" | ">" | "==" | ">=" | "<=" | "!="
                       | "is" ["not"] | ["not"] "in"

Comparisons yield boolean values: ‘True’ or ‘False’.  Custom 'rich
comparison methods' may return non-boolean values.  In this case Python
will call *note bool(): 46b. on such value in boolean contexts.

Comparisons can be chained arbitrarily, e.g., ‘x < y <= z’ is equivalent
to ‘x < y and y <= z’, except that ‘y’ is evaluated only once (but in
both cases ‘z’ is not evaluated at all when ‘x < y’ is found to be
false).

Formally, if 'a', 'b', 'c', …, 'y', 'z' are expressions and 'op1',
'op2', …, 'opN' are comparison operators, then ‘a op1 b op2 c ... y opN
z’ is equivalent to ‘a op1 b and b op2 c and ... y opN z’, except that
each expression is evaluated at most once.

Note that ‘a op1 b op2 c’ doesn’t imply any kind of comparison between
'a' and 'c', so that, e.g., ‘x < y > z’ is perfectly legal (though
perhaps not pretty).

* Menu:

* Value comparisons::
* Membership test operations::
* Identity comparisons::


File: python.info,  Node: Value comparisons,  Next: Membership test operations,  Up: Comparisons

4.6.10.1 Value comparisons
..........................

The operators ‘<’, ‘>’, ‘==’, ‘>=’, ‘<=’, and ‘!=’ compare the values of
two objects.  The objects do not need to have the same type.

Chapter *note Objects, values and types: 2091. states that objects have
a value (in addition to type and identity).  The value of an object is a
rather abstract notion in Python: For example, there is no canonical
access method for an object’s value.  Also, there is no requirement that
the value of an object should be constructed in a particular way, e.g.
comprised of all its data attributes.  Comparison operators implement a
particular notion of what the value of an object is.  One can think of
them as defining the value of an object indirectly, by means of their
comparison implementation.

Because all types are (direct or indirect) subtypes of *note object:
a9b, they inherit the default comparison behavior from ‘object’.  Types
can customize their comparison behavior by implementing 'rich comparison
methods' like *note __lt__(): 12e7, described in *note Basic
customization: 2113.

The default behavior for equality comparison (‘==’ and ‘!=’) is based on
the identity of the objects.  Hence, equality comparison of instances
with the same identity results in equality, and equality comparison of
instances with different identities results in inequality.  A motivation
for this default behavior is the desire that all objects should be
reflexive (i.e.  ‘x is y’ implies ‘x == y’).

A default order comparison (‘<’, ‘>’, ‘<=’, and ‘>=’) is not provided;
an attempt raises *note TypeError: 2c3.  A motivation for this default
behavior is the lack of a similar invariant as for equality.

The behavior of the default equality comparison, that instances with
different identities are always unequal, may be in contrast to what
types will need that have a sensible definition of object value and
value-based equality.  Such types will need to customize their
comparison behavior, and in fact, a number of built-in types have done
that.

The following list describes the comparison behavior of the most
important built-in types.

   * Numbers of built-in numeric types (*note Numeric Types — int,
     float, complex: 1d8d.) and of the standard library types *note
     fractions.Fraction: 1e7. and *note decimal.Decimal: 29d. can be
     compared within and across their types, with the restriction that
     complex numbers do not support order comparison.  Within the limits
     of the types involved, they compare mathematically
     (algorithmically) correct without loss of precision.

     The not-a-number values ‘float('NaN')’ and ‘decimal.Decimal('NaN')’
     are special.  Any ordered comparison of a number to a not-a-number
     value is false.  A counter-intuitive implication is that
     not-a-number values are not equal to themselves.  For example, if
     ‘x = float('NaN')’, ‘3 < x’, ‘x < 3’ and ‘x == x’ are all false,
     while ‘x != x’ is true.  This behavior is compliant with IEEE 754.

   * ‘None’ and *note NotImplemented: 7d6. are singletons.  PEP 8(1)
     advises that comparisons for singletons should always be done with
     ‘is’ or ‘is not’, never the equality operators.

   * Binary sequences (instances of *note bytes: 1c2. or *note
     bytearray: 2ea.) can be compared within and across their types.
     They compare lexicographically using the numeric values of their
     elements.

   * Strings (instances of *note str: 44f.) compare lexicographically
     using the numerical Unicode code points (the result of the built-in
     function *note ord(): 209f.) of their characters.  (2)

     Strings and binary sequences cannot be directly compared.

   * Sequences (instances of *note tuple: 373, *note list: 614, or *note
     range: 94d.) can be compared only within each of their types, with
     the restriction that ranges do not support order comparison.
     Equality comparison across these types results in inequality, and
     ordering comparison across these types raises *note TypeError: 2c3.

     Sequences compare lexicographically using comparison of
     corresponding elements.  The built-in containers typically assume
     identical objects are equal to themselves.  That lets them bypass
     equality tests for identical objects to improve performance and to
     maintain their internal invariants.

     Lexicographical comparison between built-in collections works as
     follows:

        - For two collections to compare equal, they must be of the same
          type, have the same length, and each pair of corresponding
          elements must compare equal (for example, ‘[1,2] == (1,2)’ is
          false because the type is not the same).

        - Collections that support order comparison are ordered the same
          as their first unequal elements (for example, ‘[1,2,x] <=
          [1,2,y]’ has the same value as ‘x <= y’).  If a corresponding
          element does not exist, the shorter collection is ordered
          first (for example, ‘[1,2] < [1,2,3]’ is true).

   * Mappings (instances of *note dict: 256.) compare equal if and only
     if they have equal ‘(key, value)’ pairs.  Equality comparison of
     the keys and values enforces reflexivity.

     Order comparisons (‘<’, ‘>’, ‘<=’, and ‘>=’) raise *note TypeError:
     2c3.

   * Sets (instances of *note set: 5dc. or *note frozenset: 5dd.) can be
     compared within and across their types.

     They define order comparison operators to mean subset and superset
     tests.  Those relations do not define total orderings (for example,
     the two sets ‘{1,2}’ and ‘{2,3}’ are not equal, nor subsets of one
     another, nor supersets of one another).  Accordingly, sets are not
     appropriate arguments for functions which depend on total ordering
     (for example, *note min(): f3f, *note max(): f40, and *note
     sorted(): bed. produce undefined results given a list of sets as
     inputs).

     Comparison of sets enforces reflexivity of its elements.

   * Most other built-in types have no comparison methods implemented,
     so they inherit the default comparison behavior.

User-defined classes that customize their comparison behavior should
follow some consistency rules, if possible:

   * Equality comparison should be reflexive.  In other words, identical
     objects should compare equal:

          ‘x is y’ implies ‘x == y’

   * Comparison should be symmetric.  In other words, the following
     expressions should have the same result:

          ‘x == y’ and ‘y == x’

          ‘x != y’ and ‘y != x’

          ‘x < y’ and ‘y > x’

          ‘x <= y’ and ‘y >= x’

   * Comparison should be transitive.  The following (non-exhaustive)
     examples illustrate that:

          ‘x > y and y > z’ implies ‘x > z’

          ‘x < y and y <= z’ implies ‘x < z’

   * Inverse comparison should result in the boolean negation.  In other
     words, the following expressions should have the same result:

          ‘x == y’ and ‘not x != y’

          ‘x < y’ and ‘not x >= y’ (for total ordering)

          ‘x > y’ and ‘not x <= y’ (for total ordering)

     The last two expressions apply to totally ordered collections (e.g.
     to sequences, but not to sets or mappings).  See also the *note
     total_ordering(): f7a. decorator.

   * The *note hash(): 5ee. result should be consistent with equality.
     Objects that are equal should either have the same hash value, or
     be marked as unhashable.

Python does not enforce these consistency rules.  In fact, the
not-a-number values are an example for not following these rules.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/

   (2) The Unicode standard distinguishes between 'code points' (e.g.
U+0041) and 'abstract characters' (e.g.  “LATIN CAPITAL LETTER A”).
While most abstract characters in Unicode are only represented using one
code point, there is a number of abstract characters that can in
addition be represented using a sequence of more than one code point.
For example, the abstract character “LATIN CAPITAL LETTER C WITH
CEDILLA” can be represented as a single 'precomposed character' at code
position U+00C7, or as a sequence of a 'base character' at code position
U+0043 (LATIN CAPITAL LETTER C), followed by a 'combining character' at
code position U+0327 (COMBINING CEDILLA).

The comparison operators on strings compare at the level of Unicode code
points.  This may be counter-intuitive to humans.  For example,
‘"\u00C7" == "\u0043\u0327"’ is ‘False’, even though both strings
represent the same abstract character “LATIN CAPITAL LETTER C WITH
CEDILLA”.

To compare strings at the level of abstract characters (that is, in a
way intuitive to humans), use *note unicodedata.normalize(): 6d8.


File: python.info,  Node: Membership test operations,  Next: Identity comparisons,  Prev: Value comparisons,  Up: Comparisons

4.6.10.2 Membership test operations
...................................

The operators *note in: 2f4. and *note not in: 632. test for membership.
‘x in s’ evaluates to ‘True’ if 'x' is a member of 's', and ‘False’
otherwise.  ‘x not in s’ returns the negation of ‘x in s’.  All built-in
sequences and set types support this as well as dictionary, for which
‘in’ tests whether the dictionary has a given key.  For container types
such as list, tuple, set, frozenset, dict, or collections.deque, the
expression ‘x in y’ is equivalent to ‘any(x is e or x == e for e in y)’.

For the string and bytes types, ‘x in y’ is ‘True’ if and only if 'x' is
a substring of 'y'.  An equivalent test is ‘y.find(x) != -1’.  Empty
strings are always considered to be a substring of any other string, so
‘"" in "abc"’ will return ‘True’.

For user-defined classes which define the *note __contains__(): 1406.
method, ‘x in y’ returns ‘True’ if ‘y.__contains__(x)’ returns a true
value, and ‘False’ otherwise.

For user-defined classes which do not define *note __contains__(): 1406.
but do define *note __iter__(): c90, ‘x in y’ is ‘True’ if some value
‘z’, for which the expression ‘x is z or x == z’ is true, is produced
while iterating over ‘y’.  If an exception is raised during the
iteration, it is as if *note in: 2f4. raised that exception.

Lastly, the old-style iteration protocol is tried: if a class defines
*note __getitem__(): 283, ‘x in y’ is ‘True’ if and only if there is a
non-negative integer index 'i' such that ‘x is y[i] or x == y[i]’, and
no lower integer index raises the *note IndexError: 1585. exception.
(If any other exception is raised, it is as if *note in: 2f4. raised
that exception).

The operator *note not in: 632. is defined to have the inverse truth
value of *note in: 2f4.


File: python.info,  Node: Identity comparisons,  Prev: Membership test operations,  Up: Comparisons

4.6.10.3 Identity comparisons
.............................

The operators *note is: 2f5. and *note is not: 222f. test for an
object’s identity: ‘x is y’ is true if and only if 'x' and 'y' are the
same object.  An Object’s identity is determined using the *note id():
1471. function.  ‘x is not y’ yields the inverse truth value.  (1)

   ---------- Footnotes ----------

   (1) Due to automatic garbage-collection, free lists, and the dynamic
nature of descriptors, you may notice seemingly unusual behaviour in
certain uses of the *note is: 2f5. operator, like those involving
comparisons between instance methods, or constants.  Check their
documentation for more info.


File: python.info,  Node: Boolean operations,  Next: Assignment expressions<2>,  Prev: Comparisons,  Up: Expressions

4.6.11 Boolean operations
-------------------------

     or_test  ::= *note and_test: 2233. | *note or_test: 21df. "or" *note and_test: 2233.
     and_test ::= *note not_test: 2234. | *note and_test: 2233. "and" *note not_test: 2234.
     not_test ::= *note comparison: 222a. | "not" *note not_test: 2234.

In the context of Boolean operations, and also when expressions are used
by control flow statements, the following values are interpreted as
false: ‘False’, ‘None’, numeric zero of all types, and empty strings and
containers (including strings, tuples, lists, dictionaries, sets and
frozensets).  All other values are interpreted as true.  User-defined
objects can customize their truth value by providing a *note __bool__():
131d. method.

The operator *note not: 2232. yields ‘True’ if its argument is false,
‘False’ otherwise.

The expression ‘x and y’ first evaluates 'x'; if 'x' is false, its value
is returned; otherwise, 'y' is evaluated and the resulting value is
returned.

The expression ‘x or y’ first evaluates 'x'; if 'x' is true, its value
is returned; otherwise, 'y' is evaluated and the resulting value is
returned.

Note that neither *note and: 2f1. nor *note or: 2f6. restrict the value
and type they return to ‘False’ and ‘True’, but rather return the last
evaluated argument.  This is sometimes useful, e.g., if ‘s’ is a string
that should be replaced by a default value if it is empty, the
expression ‘s or 'foo'’ yields the desired value.  Because *note not:
2232. has to create a new value, it returns a boolean value regardless
of the type of its argument (for example, ‘not 'foo'’ produces ‘False’
rather than ‘''’.)


File: python.info,  Node: Assignment expressions<2>,  Next: Conditional expressions,  Prev: Boolean operations,  Up: Expressions

4.6.12 Assignment expressions
-----------------------------

     assignment_expression ::= [*note identifier: 2042. ":="] *note expression: 21eb.

An assignment expression (sometimes also called a “named expression” or
“walrus”) assigns an *note expression: 21eb. to an *note identifier:
2042, while also returning the value of the ‘expression’.

One common use case is when handling matched regular expressions:

     if matching := pattern.search(data):
         do_something(matching)

Or, when processing a file stream in chunks:

     while chunk := file.read(9000):
         process(chunk)

Assignment expressions must be surrounded by parentheses when used as
expression statements and when used as sub-expressions in slicing,
conditional, lambda, keyword-argument, and comprehension-if expressions
and in ‘assert’, ‘with’, and ‘assignment’ statements.  In all other
places where they can be used, parentheses are not required, including
in ‘if’ and ‘while’ statements.

Added in version 3.8: See PEP 572(1) for more details about assignment
expressions.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0572/


File: python.info,  Node: Conditional expressions,  Next: Lambdas,  Prev: Assignment expressions<2>,  Up: Expressions

4.6.13 Conditional expressions
------------------------------

     conditional_expression ::= *note or_test: 21df. ["if" *note or_test: 21df. "else" *note expression: 21eb.]
     expression             ::= *note conditional_expression: 206e. | *note lambda_expr: 2239.

A conditional expression (sometimes called a “ternary operator”) is an
alternative to the if-else statement.  As it is an expression, it
returns a value and can appear as a sub-expression.

The expression ‘x if C else y’ first evaluates the condition, 'C' rather
than 'x'.  If 'C' is true, 'x' is evaluated and its value is returned;
otherwise, 'y' is evaluated and its value is returned.

See PEP 308(1) for more details about conditional expressions.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0308/


File: python.info,  Node: Lambdas,  Next: Expression lists,  Prev: Conditional expressions,  Up: Expressions

4.6.14 Lambdas
--------------

     lambda_expr ::= "lambda" [*note parameter_list: 223c.] ":" *note expression: 21eb.

Lambda expressions (sometimes called lambda forms) are used to create
anonymous functions.  The expression ‘lambda parameters: expression’
yields a function object.  The unnamed object behaves like a function
object defined with:

     def <lambda>(parameters):
         return expression

See section *note Function definitions: 1dce. for the syntax of
parameter lists.  Note that functions created with lambda expressions
cannot contain statements or annotations.


File: python.info,  Node: Expression lists,  Next: Evaluation order,  Prev: Lambdas,  Up: Expressions

4.6.15 Expression lists
-----------------------

     starred_expression       ::= ["*"] *note or_expr: 206f.
     flexible_expression      ::= *note assignment_expression: 2191. | *note starred_expression: 21da.
     flexible_expression_list ::= *note flexible_expression: 223e. ("," *note flexible_expression: 223e.)* [","]
     starred_expression_list  ::= *note starred_expression: 21da. ("," *note starred_expression: 21da.)* [","]
     expression_list          ::= *note expression: 21eb. ("," *note expression: 21eb.)* [","]
     yield_list               ::= *note expression_list: 2240. | *note starred_expression: 21da. "," [*note starred_expression_list: 223f.]

Except when part of a list or set display, an expression list containing
at least one comma yields a tuple.  The length of the tuple is the
number of expressions in the list.  The expressions are evaluated from
left to right.

An asterisk ‘*’ denotes 'iterable unpacking'.  Its operand must be an
*note iterable: 126d.  The iterable is expanded into a sequence of
items, which are included in the new tuple, list, or set, at the site of
the unpacking.

Added in version 3.5: Iterable unpacking in expression lists, originally
proposed by PEP 448(1).

Added in version 3.11: Any item in an expression list may be starred.
See PEP 646(2).

A trailing comma is required only to create a one-item tuple, such as
‘1,’; it is optional in all other cases.  A single expression without a
trailing comma doesn’t create a tuple, but rather yields the value of
that expression.  (To create an empty tuple, use an empty pair of
parentheses: ‘()’.)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0448/

   (2) https://peps.python.org/pep-0646/


File: python.info,  Node: Evaluation order,  Next: Operator precedence,  Prev: Expression lists,  Up: Expressions

4.6.16 Evaluation order
-----------------------

Python evaluates expressions from left to right.  Notice that while
evaluating an assignment, the right-hand side is evaluated before the
left-hand side.

In the following lines, expressions will be evaluated in the arithmetic
order of their suffixes:

     expr1, expr2, expr3, expr4
     (expr1, expr2, expr3, expr4)
     {expr1: expr2, expr3: expr4}
     expr1 + expr2 * (expr3 - expr4)
     expr1(expr2, expr3, *expr4, **expr5)
     expr3, expr4 = expr1, expr2


File: python.info,  Node: Operator precedence,  Prev: Evaluation order,  Up: Expressions

4.6.17 Operator precedence
--------------------------

The following table summarizes the operator precedence in Python, from
highest precedence (most binding) to lowest precedence (least binding).
Operators in the same box have the same precedence.  Unless the syntax
is explicitly given, operators are binary.  Operators in the same box
group left to right (except for exponentiation and conditional
expressions, which group from right to left).

Note that comparisons, membership tests, and identity tests, all have
the same precedence and have a left-to-right chaining feature as
described in the *note Comparisons: 2228. section.

Operator                                            Description
                                                    
----------------------------------------------------------------------------------------------
                                                    
‘(expressions...)’,                                 Binding or parenthesized expression,
                                                    list display, dictionary display, set
‘[expressions...]’, ‘{key: value...}’,              display
‘{expressions...}’                                  

‘x[index]’, ‘x[index:index]’, ‘x(arguments...)’,    Subscription, slicing, call, attribute
‘x.attribute’                                       reference
                                                    
                                                    
*note await x: 1b9.                                 Await expression
                                                    
                                                    
‘**’                                                Exponentiation (1)
                                                    
                                                    
‘+x’, ‘-x’, ‘~x’                                    Positive, negative, bitwise NOT
                                                    
                                                    
‘*’, ‘@’, ‘/’, ‘//’, ‘%’                            Multiplication, matrix multiplication,
                                                    division, floor division, remainder (2)
                                                    
                                                    
‘+’, ‘-’                                            Addition and subtraction
                                                    
                                                    
‘<<’, ‘>>’                                          Shifts
                                                    
                                                    
‘&’                                                 Bitwise AND
                                                    
                                                    
‘^’                                                 Bitwise XOR
                                                    
                                                    
‘|’                                                 Bitwise OR
                                                    
                                                    
*note in: 2f4, *note not in: 632, *note is: 2f5,    Comparisons, including membership tests
*note is not: 222f, ‘<’, ‘<=’, ‘>’, ‘>=’, ‘!=’,     and identity tests
‘==’                                                

*note not x: 2232.                                  Boolean NOT
                                                    
                                                    
*note and: 2f1.                                     Boolean AND
                                                    
                                                    
*note or: 2f6.                                      Boolean OR
                                                    
                                                    
*note if: 2238. – ‘else’                            Conditional expression
                                                    
                                                    
*note lambda: 12e4.                                 Lambda expression
                                                    
                                                    
‘:=’                                                Assignment expression
                                                    

   ---------- Footnotes ----------

   (1) The power operator ‘**’ binds less tightly than an arithmetic or
bitwise unary operator on its right, that is, ‘2**-1’ is ‘0.5’.

   (2) The ‘%’ operator is also used for string formatting; the same
precedence applies.


File: python.info,  Node: Simple statements,  Next: Compound statements,  Prev: Expressions,  Up: The Python Language Reference

4.7 Simple statements
=====================

A simple statement is comprised within a single logical line.  Several
simple statements may occur on a single line separated by semicolons.
The syntax for simple statements is:

     simple_stmt ::= *note expression_stmt: 224a.
                     | *note assert_stmt: 224b.
                     | *note assignment_stmt: 224c.
                     | *note augmented_assignment_stmt: 224d.
                     | *note annotated_assignment_stmt: 224e.
                     | *note pass_stmt: 224f.
                     | *note del_stmt: 2250.
                     | *note return_stmt: 2251.
                     | *note yield_stmt: 2252.
                     | *note raise_stmt: 2253.
                     | *note break_stmt: 2254.
                     | *note continue_stmt: 2255.
                     | *note import_stmt: 2256.
                     | *note future_stmt: 2257.
                     | *note global_stmt: 2258.
                     | *note nonlocal_stmt: 2259.
                     | *note type_stmt: 225a.

* Menu:

* Expression statements::
* Assignment statements::
* The assert statement::
* The pass statement::
* The del statement: The del statement<2>.
* The return statement::
* The yield statement::
* The raise statement::
* The break statement::
* The continue statement::
* The import statement::
* The global statement::
* The nonlocal statement::
* The type statement::


File: python.info,  Node: Expression statements,  Next: Assignment statements,  Up: Simple statements

4.7.1 Expression statements
---------------------------

Expression statements are used (mostly interactively) to compute and
write a value, or (usually) to call a procedure (a function that returns
no meaningful result; in Python, procedures return the value ‘None’).
Other uses of expression statements are allowed and occasionally useful.
The syntax for an expression statement is:

     expression_stmt ::= *note starred_expression: 21da.

An expression statement evaluates the expression list (which may be a
single expression).

In interactive mode, if the value is not ‘None’, it is converted to a
string using the built-in *note repr(): 803. function and the resulting
string is written to standard output on a line by itself (except if the
result is ‘None’, so that procedure calls do not cause any output.)


File: python.info,  Node: Assignment statements,  Next: The assert statement,  Prev: Expression statements,  Up: Simple statements

4.7.2 Assignment statements
---------------------------

Assignment statements are used to (re)bind names to values and to modify
attributes or items of mutable objects:

     assignment_stmt ::= (*note target_list: 21de. "=")+ (*note starred_expression: 21da. | *note yield_expression: 2070.)
     target_list     ::= *note target: 225e. ("," *note target: 225e.)* [","]
     target          ::= *note identifier: 2042.
                         | "(" [*note target_list: 21de.] ")"
                         | "[" [*note target_list: 21de.] "]"
                         | *note attributeref: 21fd.
                         | *note subscription: 21fe.
                         | *note slicing: 21ff.
                         | "*" *note target: 225e.

(See section *note Primaries: 21fb. for the syntax definitions for
'attributeref', 'subscription', and 'slicing'.)

An assignment statement evaluates the expression list (remember that
this can be a single expression or a comma-separated list, the latter
yielding a tuple) and assigns the single resulting object to each of the
target lists, from left to right.

Assignment is defined recursively depending on the form of the target
(list).  When a target is part of a mutable object (an attribute
reference, subscription or slicing), the mutable object must ultimately
perform the assignment and decide about its validity, and may raise an
exception if the assignment is unacceptable.  The rules observed by
various types and the exceptions raised are given with the definition of
the object types (see section *note The standard type hierarchy: 2094.).

Assignment of an object to a target list, optionally enclosed in
parentheses or square brackets, is recursively defined as follows.

   * If the target list is a single target with no trailing comma,
     optionally in parentheses, the object is assigned to that target.

   * Else:

        * If the target list contains one target prefixed with an
          asterisk, called a “starred” target: The object must be an
          iterable with at least as many items as there are targets in
          the target list, minus one.  The first items of the iterable
          are assigned, from left to right, to the targets before the
          starred target.  The final items of the iterable are assigned
          to the targets after the starred target.  A list of the
          remaining items in the iterable is then assigned to the
          starred target (the list can be empty).

        * Else: The object must be an iterable with the same number of
          items as there are targets in the target list, and the items
          are assigned, from left to right, to the corresponding
          targets.

Assignment of an object to a single target is recursively defined as
follows.

   * If the target is an identifier (name):

        * If the name does not occur in a *note global: 18a. or *note
          nonlocal: 12ef. statement in the current code block: the name
          is bound to the object in the current local namespace.

        * Otherwise: the name is bound to the object in the global
          namespace or the outer namespace determined by *note nonlocal:
          12ef, respectively.

     The name is rebound if it was already bound.  This may cause the
     reference count for the object previously bound to the name to
     reach zero, causing the object to be deallocated and its destructor
     (if it has one) to be called.

   * If the target is an attribute reference: The primary expression in
     the reference is evaluated.  It should yield an object with
     assignable attributes; if this is not the case, *note TypeError:
     2c3. is raised.  That object is then asked to assign the assigned
     object to the given attribute; if it cannot perform the assignment,
     it raises an exception (usually but not necessarily *note
     AttributeError: 34e.).  Note: If the object is a class instance and
     the attribute reference occurs on both sides of the assignment
     operator, the right-hand side expression, ‘a.x’ can access either
     an instance attribute or (if no instance attribute exists) a class
     attribute.  The left-hand side target ‘a.x’ is always set as an
     instance attribute, creating it if necessary.  Thus, the two
     occurrences of ‘a.x’ do not necessarily refer to the same
     attribute: if the right-hand side expression refers to a class
     attribute, the left-hand side creates a new instance attribute as
     the target of the assignment:

          class Cls:
              x = 3             # class variable
          inst = Cls()
          inst.x = inst.x + 1   # writes inst.x as 4 leaving Cls.x as 3

     This description does not necessarily apply to descriptor
     attributes, such as properties created with *note property(): 194.

   * If the target is a subscription: The primary expression in the
     reference is evaluated.  It should yield either a mutable sequence
     object (such as a list) or a mapping object (such as a dictionary).
     Next, the subscript expression is evaluated.

     If the primary is a mutable sequence object (such as a list), the
     subscript must yield an integer.  If it is negative, the sequence’s
     length is added to it.  The resulting value must be a nonnegative
     integer less than the sequence’s length, and the sequence is asked
     to assign the assigned object to its item with that index.  If the
     index is out of range, *note IndexError: 1585. is raised
     (assignment to a subscripted sequence cannot add new items to a
     list).

     If the primary is a mapping object (such as a dictionary), the
     subscript must have a type compatible with the mapping’s key type,
     and the mapping is then asked to create a key/value pair which maps
     the subscript to the assigned object.  This can either replace an
     existing key/value pair with the same key value, or insert a new
     key/value pair (if no key with the same value existed).

     For user-defined objects, the *note __setitem__(): 1313. method is
     called with appropriate arguments.

   * If the target is a slicing: The primary expression in the reference
     is evaluated.  It should yield a mutable sequence object (such as a
     list).  The assigned object should be a sequence object of the same
     type.  Next, the lower and upper bound expressions are evaluated,
     insofar they are present; defaults are zero and the sequence’s
     length.  The bounds should evaluate to integers.  If either bound
     is negative, the sequence’s length is added to it.  The resulting
     bounds are clipped to lie between zero and the sequence’s length,
     inclusive.  Finally, the sequence object is asked to replace the
     slice with the items of the assigned sequence.  The length of the
     slice may be different from the length of the assigned sequence,
     thus changing the length of the target sequence, if the target
     sequence allows it.

'CPython implementation detail:' In the current implementation, the
syntax for targets is taken to be the same as for expressions, and
invalid syntax is rejected during the code generation phase, causing
less detailed error messages.

Although the definition of assignment implies that overlaps between the
left-hand side and the right-hand side are ‘simultaneous’ (for example
‘a, b = b, a’ swaps two variables), overlaps 'within' the collection of
assigned-to variables occur left-to-right, sometimes resulting in
confusion.  For instance, the following program prints ‘[0, 2]’:

     x = [0, 1]
     i = 0
     i, x[i] = 1, 2         # i is updated, then x[i] is updated
     print(x)

See also
........

PEP 3132(1) - Extended Iterable Unpacking

     The specification for the ‘*target’ feature.

* Menu:

* Augmented assignment statements::
* Annotated assignment statements::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3132/


File: python.info,  Node: Augmented assignment statements,  Next: Annotated assignment statements,  Up: Assignment statements

4.7.2.1 Augmented assignment statements
.......................................

Augmented assignment is the combination, in a single statement, of a
binary operation and an assignment statement:

     augmented_assignment_stmt ::= *note augtarget: 2262. *note augop: 2263. (*note expression_list: 2240. | *note yield_expression: 2070.)
     augtarget                 ::= *note identifier: 2042. | *note attributeref: 21fd. | *note subscription: 21fe. | *note slicing: 21ff.
     augop                     ::= "+=" | "-=" | "*=" | "@=" | "/=" | "//=" | "%=" | "**="
                                   | ">>=" | "<<=" | "&=" | "^=" | "|="

(See section *note Primaries: 21fb. for the syntax definitions of the
last three symbols.)

An augmented assignment evaluates the target (which, unlike normal
assignment statements, cannot be an unpacking) and the expression list,
performs the binary operation specific to the type of assignment on the
two operands, and assigns the result to the original target.  The target
is only evaluated once.

An augmented assignment statement like ‘x += 1’ can be rewritten as ‘x =
x + 1’ to achieve a similar, but not exactly equal effect.  In the
augmented version, ‘x’ is only evaluated once.  Also, when possible, the
actual operation is performed 'in-place', meaning that rather than
creating a new object and assigning that to the target, the old object
is modified instead.

Unlike normal assignments, augmented assignments evaluate the left-hand
side 'before' evaluating the right-hand side.  For example, ‘a[i] +=
f(x)’ first looks-up ‘a[i]’, then it evaluates ‘f(x)’ and performs the
addition, and lastly, it writes the result back to ‘a[i]’.

With the exception of assigning to tuples and multiple targets in a
single statement, the assignment done by augmented assignment statements
is handled the same way as normal assignments.  Similarly, with the
exception of the possible 'in-place' behavior, the binary operation
performed by augmented assignment is the same as the normal binary
operations.

For targets which are attribute references, the same *note caveat about
class and instance attributes: 225f. applies as for regular assignments.


File: python.info,  Node: Annotated assignment statements,  Prev: Augmented assignment statements,  Up: Assignment statements

4.7.2.2 Annotated assignment statements
.......................................

*note Annotation: d7f. assignment is the combination, in a single
statement, of a variable or attribute annotation and an optional
assignment statement:

     annotated_assignment_stmt ::= *note augtarget: 2262. ":" *note expression: 21eb.
                                   ["=" (*note starred_expression: 21da. | *note yield_expression: 2070.)]

The difference from normal *note Assignment statements: 218b. is that
only a single target is allowed.

The assignment target is considered “simple” if it consists of a single
name that is not enclosed in parentheses.  For simple assignment
targets, if in class or module scope, the annotations are evaluated and
stored in a special class or module attribute ‘__annotations__’ that is
a dictionary mapping from variable names (mangled if private) to
evaluated annotations.  This attribute is writable and is automatically
created at the start of class or module body execution, if annotations
are found statically.

If the assignment target is not simple (an attribute, subscript node, or
parenthesized name), the annotation is evaluated if in class or module
scope, but not stored.

If a name is annotated in a function scope, then this name is local for
that scope.  Annotations are never evaluated and stored in function
scopes.

If the right hand side is present, an annotated assignment performs the
actual assignment before evaluating annotations (where applicable).  If
the right hand side is not present for an expression target, then the
interpreter evaluates the target except for the last *note
__setitem__(): 1313. or *note __setattr__(): 20de. call.

See also
........

PEP 526(1) - Syntax for Variable Annotations

     The proposal that added syntax for annotating the types of
     variables (including class variables and instance variables),
     instead of expressing them through comments.

PEP 484(2) - Type hints

     The proposal that added the *note typing: 104. module to provide a
     standard syntax for type annotations that can be used in static
     analysis tools and IDEs.

Changed in version 3.8: Now annotated assignments allow the same
expressions in the right hand side as regular assignments.  Previously,
some expressions (like un-parenthesized tuple expressions) caused a
syntax error.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0526/

   (2) https://peps.python.org/pep-0484/


File: python.info,  Node: The assert statement,  Next: The pass statement,  Prev: Assignment statements,  Up: Simple statements

4.7.3 The ‘assert’ statement
----------------------------

Assert statements are a convenient way to insert debugging assertions
into a program:

     assert_stmt ::= "assert" *note expression: 21eb. ["," *note expression: 21eb.]

The simple form, ‘assert expression’, is equivalent to

     if __debug__:
         if not expression: raise AssertionError

The extended form, ‘assert expression1, expression2’, is equivalent to

     if __debug__:
         if not expression1: raise AssertionError(expression2)

These equivalences assume that *note __debug__: 7de. and *note
AssertionError: 6ac. refer to the built-in variables with those names.
In the current implementation, the built-in variable ‘__debug__’ is
‘True’ under normal circumstances, ‘False’ when optimization is
requested (command line option *note -O: de3.).  The current code
generator emits no code for an *note assert: 972. statement when
optimization is requested at compile time.  Note that it is unnecessary
to include the source code for the expression that failed in the error
message; it will be displayed as part of the stack trace.

Assignments to *note __debug__: 7de. are illegal.  The value for the
built-in variable is determined when the interpreter starts.


File: python.info,  Node: The pass statement,  Next: The del statement<2>,  Prev: The assert statement,  Up: Simple statements

4.7.4 The ‘pass’ statement
--------------------------

     pass_stmt ::= "pass"

*note pass: 1db1. is a null operation — when it is executed, nothing
happens.  It is useful as a placeholder when a statement is required
syntactically, but no code needs to be executed, for example:

     def f(arg): pass    # a function that does nothing (yet)

     class C: pass       # a class with no methods (yet)


File: python.info,  Node: The del statement<2>,  Next: The return statement,  Prev: The pass statement,  Up: Simple statements

4.7.5 The ‘del’ statement
-------------------------

     del_stmt ::= "del" *note target_list: 21de.

Deletion is recursively defined very similar to the way assignment is
defined.  Rather than spelling it out in full details, here are some
hints.

Deletion of a target list recursively deletes each target, from left to
right.

Deletion of a name removes the binding of that name from the local or
global namespace, depending on whether the name occurs in a *note
global: 18a. statement in the same code block.  Trying to delete an
unbound name raises a *note NameError: 442. exception.

Deletion of attribute references, subscriptions and slicings is passed
to the primary object involved; deletion of a slicing is in general
equivalent to assignment of an empty slice of the right type (but even
this is determined by the sliced object).

Changed in version 3.2: Previously it was illegal to delete a name from
the local namespace if it occurs as a free variable in a nested block.


File: python.info,  Node: The return statement,  Next: The yield statement,  Prev: The del statement<2>,  Up: Simple statements

4.7.6 The ‘return’ statement
----------------------------

     return_stmt ::= "return" [*note expression_list: 2240.]

*note return: 9d9. may only occur syntactically nested in a function
definition, not within a nested class definition.

If an expression list is present, it is evaluated, else ‘None’ is
substituted.

*note return: 9d9. leaves the current function call with the expression
list (or ‘None’) as return value.

When *note return: 9d9. passes control out of a *note try: 6ec.
statement with a *note finally: 9d5. clause, that ‘finally’ clause is
executed before really leaving the function.

In a generator function, the *note return: 9d9. statement indicates that
the generator is done and will cause *note StopIteration: c1b. to be
raised.  The returned value (if any) is used as an argument to construct
‘StopIteration’ and becomes the *note StopIteration.value: 217a.
attribute.

In an asynchronous generator function, an empty *note return: 9d9.
statement indicates that the asynchronous generator is done and will
cause *note StopAsyncIteration: 1bbe. to be raised.  A non-empty
‘return’ statement is a syntax error in an asynchronous generator
function.


File: python.info,  Node: The yield statement,  Next: The raise statement,  Prev: The return statement,  Up: Simple statements

4.7.7 The ‘yield’ statement
---------------------------

     yield_stmt ::= *note yield_expression: 2070.

A *note yield: 9d8. statement is semantically equivalent to a *note
yield expression: 21ef.  The ‘yield’ statement can be used to omit the
parentheses that would otherwise be required in the equivalent yield
expression statement.  For example, the yield statements

     yield <expr>
     yield from <expr>

are equivalent to the yield expression statements

     (yield <expr>)
     (yield from <expr>)

Yield expressions and statements are only used when defining a *note
generator: 109f. function, and are only used in the body of the
generator function.  Using *note yield: 9d8. in a function definition is
sufficient to cause that definition to create a generator function
instead of a normal function.

For full details of *note yield: 9d8. semantics, refer to the *note
Yield expressions: 21ef. section.


File: python.info,  Node: The raise statement,  Next: The break statement,  Prev: The yield statement,  Up: Simple statements

4.7.8 The ‘raise’ statement
---------------------------

     raise_stmt ::= "raise" [*note expression: 21eb. ["from" *note expression: 21eb.]]

If no expressions are present, *note raise: 5f0. re-raises the exception
that is currently being handled, which is also known as the 'active
exception'.  If there isn’t currently an active exception, a *note
RuntimeError: 195. exception is raised indicating that this is an error.

Otherwise, *note raise: 5f0. evaluates the first expression as the
exception object.  It must be either a subclass or an instance of *note
BaseException: 5be.  If it is a class, the exception instance will be
obtained when needed by instantiating the class with no arguments.

The 'type' of the exception is the exception instance’s class, the
'value' is the instance itself.

A traceback object is normally created automatically when an exception
is raised and attached to it as the *note __traceback__: 130e.
attribute.  You can create an exception and set your own traceback in
one step using the *note with_traceback(): 226c. exception method (which
returns the same exception instance, with its traceback set to its
argument), like so:

     raise Exception("foo occurred").with_traceback(tracebackobj)

The ‘from’ clause is used for exception chaining: if given, the second
'expression' must be another exception class or instance.  If the second
expression is an exception instance, it will be attached to the raised
exception as the *note __cause__: 1310. attribute (which is writable).
If the expression is an exception class, the class will be instantiated
and the resulting exception instance will be attached to the raised
exception as the ‘__cause__’ attribute.  If the raised exception is not
handled, both exceptions will be printed:

     >>> try:
     ...     print(1 / 0)
     ... except Exception as exc:
     ...     raise RuntimeError("Something bad happened") from exc
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         print(1 / 0)
               ~~^~~
     ZeroDivisionError: division by zero

     The above exception was the direct cause of the following exception:

     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
         raise RuntimeError("Something bad happened") from exc
     RuntimeError: Something bad happened

A similar mechanism works implicitly if a new exception is raised when
an exception is already being handled.  An exception may be handled when
an *note except: 18b. or *note finally: 9d5. clause, or a *note with:
5d5. statement, is used.  The previous exception is then attached as the
new exception’s *note __context__: 130f. attribute:

     >>> try:
     ...     print(1 / 0)
     ... except:
     ...     raise RuntimeError("Something bad happened")
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
         print(1 / 0)
               ~~^~~
     ZeroDivisionError: division by zero

     During handling of the above exception, another exception occurred:

     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
         raise RuntimeError("Something bad happened")
     RuntimeError: Something bad happened

Exception chaining can be explicitly suppressed by specifying *note
None: 678. in the ‘from’ clause:

     >>> try:
     ...     print(1 / 0)
     ... except:
     ...     raise RuntimeError("Something bad happened") from None
     ...
     Traceback (most recent call last):
       File "<stdin>", line 4, in <module>
     RuntimeError: Something bad happened

Additional information on exceptions can be found in section *note
Exceptions: 2197, and information about handling exceptions is in
section *note The try statement: 6ec.

Changed in version 3.3: *note None: 678. is now permitted as ‘Y’ in
‘raise X from Y’.

Added the *note __suppress_context__: 226d. attribute to suppress
automatic display of the exception context.

Changed in version 3.11: If the traceback of the active exception is
modified in an *note except: 18b. clause, a subsequent ‘raise’ statement
re-raises the exception with the modified traceback.  Previously, the
exception was re-raised with the traceback it had when it was caught.


File: python.info,  Node: The break statement,  Next: The continue statement,  Prev: The raise statement,  Up: Simple statements

4.7.9 The ‘break’ statement
---------------------------

     break_stmt ::= "break"

*note break: abe. may only occur syntactically nested in a *note for:
2f2. or *note while: 1d9a. loop, but not nested in a function or class
definition within that loop.

It terminates the nearest enclosing loop, skipping the optional ‘else’
clause if the loop has one.

If a *note for: 2f2. loop is terminated by *note break: abe, the loop
control target keeps its current value.

When *note break: abe. passes control out of a *note try: 6ec. statement
with a *note finally: 9d5. clause, that ‘finally’ clause is executed
before really leaving the loop.


File: python.info,  Node: The continue statement,  Next: The import statement,  Prev: The break statement,  Up: Simple statements

4.7.10 The ‘continue’ statement
-------------------------------

     continue_stmt ::= "continue"

*note continue: 9d4. may only occur syntactically nested in a *note for:
2f2. or *note while: 1d9a. loop, but not nested in a function or class
definition within that loop.  It continues with the next cycle of the
nearest enclosing loop.

When *note continue: 9d4. passes control out of a *note try: 6ec.
statement with a *note finally: 9d5. clause, that ‘finally’ clause is
executed before really starting the next loop cycle.


File: python.info,  Node: The import statement,  Next: The global statement,  Prev: The continue statement,  Up: Simple statements

4.7.11 The ‘import’ statement
-----------------------------

     import_stmt     ::= "import" *note module: 2271. ["as" *note identifier: 2042.] ("," *note module: 2271. ["as" *note identifier: 2042.])*
                         | "from" *note relative_module: 2272. "import" *note identifier: 2042. ["as" *note identifier: 2042.]
                         ("," *note identifier: 2042. ["as" *note identifier: 2042.])*
                         | "from" *note relative_module: 2272. "import" "(" *note identifier: 2042. ["as" *note identifier: 2042.]
                         ("," *note identifier: 2042. ["as" *note identifier: 2042.])* [","] ")"
                         | "from" *note relative_module: 2272. "import" "*"
     module          ::= (*note identifier: 2042. ".")* *note identifier: 2042.
     relative_module ::= "."* *note module: 2271. | "."+

The basic import statement (no *note from: 12f3. clause) is executed in
two steps:

  1. find a module, loading and initializing it if necessary

  2. define a name or names in the local namespace for the scope where
     the *note import: 5e5. statement occurs.

When the statement contains multiple clauses (separated by commas) the
two steps are carried out separately for each clause, just as though the
clauses had been separated out into individual import statements.

The details of the first step, finding and loading modules, are
described in greater detail in the section on the *note import system:
20c2, which also describes the various types of packages and modules
that can be imported, as well as all the hooks that can be used to
customize the import system.  Note that failures in this step may
indicate either that the module could not be located, 'or' that an error
occurred while initializing the module, which includes execution of the
module’s code.

If the requested module is retrieved successfully, it will be made
available in the local namespace in one of three ways:

   * If the module name is followed by ‘as’, then the name following
     ‘as’ is bound directly to the imported module.

   * If no other name is specified, and the module being imported is a
     top level module, the module’s name is bound in the local namespace
     as a reference to the imported module

   * If the module being imported is 'not' a top level module, then the
     name of the top level package that contains the module is bound in
     the local namespace as a reference to the top level package.  The
     imported module must be accessed using its full qualified name
     rather than directly

The *note from: 12f3. form uses a slightly more complex process:

  1. find the module specified in the *note from: 12f3. clause, loading
     and initializing it if necessary;

  2. for each of the identifiers specified in the *note import: 5e5.
     clauses:

       1. check if the imported module has an attribute by that name

       2. if not, attempt to import a submodule with that name and then
          check the imported module again for that attribute

       3. if the attribute is not found, *note ImportError: 41c. is
          raised.

       4. otherwise, a reference to that value is stored in the local
          namespace, using the name in the ‘as’ clause if it is present,
          otherwise using the attribute name

Examples:

     import foo                 # foo imported and bound locally
     import foo.bar.baz         # foo, foo.bar, and foo.bar.baz imported, foo bound locally
     import foo.bar.baz as fbb  # foo, foo.bar, and foo.bar.baz imported, foo.bar.baz bound as fbb
     from foo.bar import baz    # foo, foo.bar, and foo.bar.baz imported, foo.bar.baz bound as baz
     from foo import attr       # foo imported and foo.attr bound as attr

If the list of identifiers is replaced by a star (‘'*'’), all public
names defined in the module are bound in the local namespace for the
scope where the *note import: 5e5. statement occurs.

The 'public names' defined by a module are determined by checking the
module’s namespace for a variable named ‘__all__’; if defined, it must
be a sequence of strings which are names defined or imported by that
module.  Names containing non-ASCII characters must be in the
normalization form(1) NFKC. The names given in ‘__all__’ are all
considered public and are required to exist.  If ‘__all__’ is not
defined, the set of public names includes all names found in the
module’s namespace which do not begin with an underscore character
(‘'_'’).  ‘__all__’ should contain the entire public API. It is intended
to avoid accidentally exporting items that are not part of the API (such
as library modules which were imported and used within the module).

The wild card form of import — ‘from module import *’ — is only allowed
at the module level.  Attempting to use it in class or function
definitions will raise a *note SyntaxError: 18d.

When specifying what module to import you do not have to specify the
absolute name of the module.  When a module or package is contained
within another package it is possible to make a relative import within
the same top package without having to mention the package name.  By
using leading dots in the specified module or package after *note from:
12f3. you can specify how high to traverse up the current package
hierarchy without specifying exact names.  One leading dot means the
current package where the module making the import exists.  Two dots
means up one package level.  Three dots is up two levels, etc.  So if
you execute ‘from . import mod’ from a module in the ‘pkg’ package then
you will end up importing ‘pkg.mod’.  If you execute ‘from ..subpkg2
import mod’ from within ‘pkg.subpkg1’ you will import ‘pkg.subpkg2.mod’.
The specification for relative imports is contained in the *note Package
Relative Imports: 21bd. section.

*note importlib.import_module(): 51b. is provided to support
applications that determine dynamically the modules to be loaded.

Raises an *note auditing event: 1a15. ‘import’ with arguments ‘module’,
‘filename’, ‘sys.path’, ‘sys.meta_path’, ‘sys.path_hooks’.

* Menu:

* Future statements::

   ---------- Footnotes ----------

   (1) https://www.unicode.org/reports/tr15/#Norm_Forms


File: python.info,  Node: Future statements,  Up: The import statement

4.7.11.1 Future statements
..........................

A 'future statement' is a directive to the compiler that a particular
module should be compiled using syntax or semantics that will be
available in a specified future release of Python where the feature
becomes standard.

The future statement is intended to ease migration to future versions of
Python that introduce incompatible changes to the language.  It allows
use of the new features on a per-module basis before the release in
which the feature becomes standard.

     future_stmt ::= "from" "__future__" "import" *note feature: 2274. ["as" *note identifier: 2042.]
                     ("," *note feature: 2274. ["as" *note identifier: 2042.])*
                     | "from" "__future__" "import" "(" *note feature: 2274. ["as" *note identifier: 2042.]
                     ("," *note feature: 2274. ["as" *note identifier: 2042.])* [","] ")"
     feature     ::= *note identifier: 2042.

A future statement must appear near the top of the module.  The only
lines that can appear before a future statement are:

   * the module docstring (if any),

   * comments,

   * blank lines, and

   * other future statements.

The only feature that requires using the future statement is
‘annotations’ (see PEP 563(1)).

All historical features enabled by the future statement are still
recognized by Python 3.  The list includes ‘absolute_import’,
‘division’, ‘generators’, ‘generator_stop’, ‘unicode_literals’,
‘print_function’, ‘nested_scopes’ and ‘with_statement’.  They are all
redundant because they are always enabled, and only kept for backwards
compatibility.

A future statement is recognized and treated specially at compile time:
Changes to the semantics of core constructs are often implemented by
generating different code.  It may even be the case that a new feature
introduces new incompatible syntax (such as a new reserved word), in
which case the compiler may need to parse the module differently.  Such
decisions cannot be pushed off until runtime.

For any given release, the compiler knows which feature names have been
defined, and raises a compile-time error if a future statement contains
a feature not known to it.

The direct runtime semantics are the same as for any import statement:
there is a standard module *note __future__: 0, described later, and it
will be imported in the usual way at the time the future statement is
executed.

The interesting runtime semantics depend on the specific feature enabled
by the future statement.

Note that there is nothing special about the statement:

     import __future__ [as name]

That is not a future statement; it’s an ordinary import statement with
no special semantics or syntax restrictions.

Code compiled by calls to the built-in functions *note exec(): 17f. and
*note compile(): 192. that occur in a module ‘M’ containing a future
statement will, by default, use the new syntax or semantics associated
with the future statement.  This can be controlled by optional arguments
to ‘compile()’ — see the documentation of that function for details.

A future statement typed at an interactive interpreter prompt will take
effect for the rest of the interpreter session.  If an interpreter is
started with the *note -i: 152a. option, is passed a script name to
execute, and the script includes a future statement, it will be in
effect in the interactive session started after the script is executed.

See also
........

PEP 236(2) - Back to the __future__

     The original proposal for the __future__ mechanism.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0563/

   (2) https://peps.python.org/pep-0236/


File: python.info,  Node: The global statement,  Next: The nonlocal statement,  Prev: The import statement,  Up: Simple statements

4.7.12 The ‘global’ statement
-----------------------------

     global_stmt ::= "global" *note identifier: 2042. ("," *note identifier: 2042.)*

The *note global: 18a. statement causes the listed identifiers to be
interpreted as globals.  It would be impossible to assign to a global
variable without ‘global’, although free variables may refer to globals
without being declared global.

The ‘global’ statement applies to the entire current scope (module,
function body or class definition).  A *note SyntaxError: 18d. is raised
if a variable is used or assigned to prior to its global declaration in
the scope.

At the module level, all variables are global, so a ‘global’ statement
has no effect.  However, variables must still not be used or assigned to
prior to their ‘global’ declaration.  This requirement is relaxed in the
interactive prompt (*note REPL: 16a.).

'Programmer’s note:' *note global: 18a. is a directive to the parser.
It applies only to code parsed at the same time as the ‘global’
statement.  In particular, a ‘global’ statement contained in a string or
code object supplied to the built-in *note exec(): 17f. function does
not affect the code block 'containing' the function call, and code
contained in such a string is unaffected by ‘global’ statements in the
code containing the function call.  The same applies to the *note
eval(): 180. and *note compile(): 192. functions.


File: python.info,  Node: The nonlocal statement,  Next: The type statement,  Prev: The global statement,  Up: Simple statements

4.7.13 The ‘nonlocal’ statement
-------------------------------

     nonlocal_stmt ::= "nonlocal" *note identifier: 2042. ("," *note identifier: 2042.)*

When the definition of a function or class is nested (enclosed) within
the definitions of other functions, its nonlocal scopes are the local
scopes of the enclosing functions.  The *note nonlocal: 12ef. statement
causes the listed identifiers to refer to names previously bound in
nonlocal scopes.  It allows encapsulated code to rebind such nonlocal
identifiers.  If a name is bound in more than one nonlocal scope, the
nearest binding is used.  If a name is not bound in any nonlocal scope,
or if there is no nonlocal scope, a *note SyntaxError: 18d. is raised.

The *note nonlocal: 12ef. statement applies to the entire scope of a
function or class body.  A *note SyntaxError: 18d. is raised if a
variable is used or assigned to prior to its nonlocal declaration in the
scope.

See also
........

PEP 3104(1) - Access to Names in Outer Scopes

     The specification for the *note nonlocal: 12ef. statement.

'Programmer’s note:' *note nonlocal: 12ef. is a directive to the parser
and applies only to code parsed along with it.  See the note for the
*note global: 18a. statement.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3104/


File: python.info,  Node: The type statement,  Prev: The nonlocal statement,  Up: Simple statements

4.7.14 The ‘type’ statement
---------------------------

     type_stmt ::= 'type' *note identifier: 2042. [*note type_params: 2278.] "=" *note expression: 21eb.

The ‘type’ statement declares a type alias, which is an instance of
*note typing.TypeAliasType: 458.

For example, the following statement creates a type alias:

     type Point = tuple[float, float]

This code is roughly equivalent to:

     annotation-def VALUE_OF_Point():
         return tuple[float, float]
     Point = typing.TypeAliasType("Point", VALUE_OF_Point())

‘annotation-def’ indicates an *note annotation scope: 188, which behaves
mostly like a function, but with several small differences.

The value of the type alias is evaluated in the annotation scope.  It is
not evaluated when the type alias is created, but only when the value is
accessed through the type alias’s ‘__value__’ attribute (see *note Lazy
evaluation: 45a.).  This allows the type alias to refer to names that
are not yet defined.

Type aliases may be made generic by adding a *note type parameter list:
2b3. after the name.  See *note Generic type aliases: 459. for more.

‘type’ is a *note soft keyword: 812.

Added in version 3.12.

See also
........

PEP 695(1) - Type Parameter Syntax

     Introduced the ‘type’ statement and syntax for generic classes and
     functions.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0695/


File: python.info,  Node: Compound statements,  Next: Top-level components,  Prev: Simple statements,  Up: The Python Language Reference

4.8 Compound statements
=======================

Compound statements contain (groups of) other statements; they affect or
control the execution of those other statements in some way.  In
general, compound statements span multiple lines, although in simple
incarnations a whole compound statement may be contained in one line.

The *note if: 2f3, *note while: 1d9a. and *note for: 2f2. statements
implement traditional control flow constructs.  *note try: 6ec.
specifies exception handlers and/or cleanup code for a group of
statements, while the *note with: 5d5. statement allows the execution of
initialization and finalization code around a block of code.  Function
and class definitions are also syntactically compound statements.

A compound statement consists of one or more ‘clauses.’ A clause
consists of a header and a ‘suite.’ The clause headers of a particular
compound statement are all at the same indentation level.  Each clause
header begins with a uniquely identifying keyword and ends with a colon.
A suite is a group of statements controlled by a clause.  A suite can be
one or more semicolon-separated simple statements on the same line as
the header, following the header’s colon, or it can be one or more
indented statements on subsequent lines.  Only the latter form of a
suite can contain nested compound statements; the following is illegal,
mostly because it wouldn’t be clear to which *note if: 2f3. clause a
following *note else: 18c. clause would belong:

     if test1: if test2: print(x)

Also note that the semicolon binds tighter than the colon in this
context, so that in the following example, either all or none of the
*note print(): fae. calls are executed:

     if x < y < z: print(x); print(y); print(z)

Summarizing:

     compound_stmt ::= *note if_stmt: 227e.
                       | *note while_stmt: 227f.
                       | *note for_stmt: 2280.
                       | *note try_stmt: 2281.
                       | *note with_stmt: 2282.
                       | *note match_stmt: 2283.
                       | *note funcdef: 2284.
                       | *note classdef: 2285.
                       | *note async_with_stmt: 2286.
                       | *note async_for_stmt: 2287.
                       | *note async_funcdef: 2288.
     suite         ::= *note stmt_list: 228a. NEWLINE | NEWLINE INDENT *note statement: 228b.+ DEDENT
     statement     ::= *note stmt_list: 228a. NEWLINE | *note compound_stmt: 227d.
     stmt_list     ::= *note simple_stmt: 2249. (";" *note simple_stmt: 2249.)* [";"]

Note that statements always end in a ‘NEWLINE’ possibly followed by a
‘DEDENT’.  Also note that optional continuation clauses always begin
with a keyword that cannot start a statement, thus there are no
ambiguities (the ‘dangling *note else: 18c.’ problem is solved in Python
by requiring nested *note if: 2f3. statements to be indented).

The formatting of the grammar rules in the following sections places
each clause on a separate line for clarity.
* Menu:

* The if statement::
* The while statement::
* The for statement::
* The try statement::
* The with statement::
* The match statement::
* Function definitions::
* Class definitions::
* Coroutines: Coroutines<2>.
* Type parameter lists::


File: python.info,  Node: The if statement,  Next: The while statement,  Up: Compound statements

4.8.1 The ‘if’ statement
------------------------

The *note if: 2f3. statement is used for conditional execution:

     if_stmt ::= "if" *note assignment_expression: 2191. ":" *note suite: 2289.
                 ("elif" *note assignment_expression: 2191. ":" *note suite: 2289.)*
                 ["else" ":" *note suite: 2289.]

It selects exactly one of the suites by evaluating the expressions one
by one until one is found to be true (see section *note Boolean
operations: 2230. for the definition of true and false); then that suite
is executed (and no other part of the *note if: 2f3. statement is
executed or evaluated).  If all expressions are false, the suite of the
*note else: 18c. clause, if present, is executed.


File: python.info,  Node: The while statement,  Next: The for statement,  Prev: The if statement,  Up: Compound statements

4.8.2 The ‘while’ statement
---------------------------

The *note while: 1d9a. statement is used for repeated execution as long
as an expression is true:

     while_stmt ::= "while" *note assignment_expression: 2191. ":" *note suite: 2289.
                    ["else" ":" *note suite: 2289.]

This repeatedly tests the expression and, if it is true, executes the
first suite; if the expression is false (which may be the first time it
is tested) the suite of the ‘else’ clause, if present, is executed and
the loop terminates.

A *note break: abe. statement executed in the first suite terminates the
loop without executing the ‘else’ clause’s suite.  A *note continue:
9d4. statement executed in the first suite skips the rest of the suite
and goes back to testing the expression.


File: python.info,  Node: The for statement,  Next: The try statement,  Prev: The while statement,  Up: Compound statements

4.8.3 The ‘for’ statement
-------------------------

The *note for: 2f2. statement is used to iterate over the elements of a
sequence (such as a string, tuple or list) or other iterable object:

     for_stmt ::= "for" *note target_list: 21de. "in" `!starred_list` ":" *note suite: 2289.
                  ["else" ":" *note suite: 2289.]

The ‘starred_list’ expression is evaluated once; it should yield an
*note iterable: 126d. object.  An *note iterator: 1ac. is created for
that iterable.  The first item provided by the iterator is then assigned
to the target list using the standard rules for assignments (see *note
Assignment statements: 218b.), and the suite is executed.  This repeats
for each item provided by the iterator.  When the iterator is exhausted,
the suite in the ‘else’ clause, if present, is executed, and the loop
terminates.

A *note break: abe. statement executed in the first suite terminates the
loop without executing the ‘else’ clause’s suite.  A *note continue:
9d4. statement executed in the first suite skips the rest of the suite
and continues with the next item, or with the ‘else’ clause if there is
no next item.

The for-loop makes assignments to the variables in the target list.
This overwrites all previous assignments to those variables including
those made in the suite of the for-loop:

     for i in range(10):
         print(i)
         i = 5             # this will not affect the for-loop
                           # because i will be overwritten with the next
                           # index in the range

Names in the target list are not deleted when the loop is finished, but
if the sequence is empty, they will not have been assigned to at all by
the loop.  Hint: the built-in type *note range(): 94d. represents
immutable arithmetic sequences of integers.  For instance, iterating
‘range(3)’ successively yields 0, 1, and then 2.

Changed in version 3.11: Starred elements are now allowed in the
expression list.


File: python.info,  Node: The try statement,  Next: The with statement,  Prev: The for statement,  Up: Compound statements

4.8.4 The ‘try’ statement
-------------------------

The ‘try’ statement specifies exception handlers and/or cleanup code for
a group of statements:

     try_stmt  ::= *note try1_stmt: 2290. | *note try2_stmt: 2291. | *note try3_stmt: 2292.
     try1_stmt ::= "try" ":" *note suite: 2289.
                   ("except" [*note expression: 21eb. ["as" *note identifier: 2042.]] ":" *note suite: 2289.)+
                   ["else" ":" *note suite: 2289.]
                   ["finally" ":" *note suite: 2289.]
     try2_stmt ::= "try" ":" *note suite: 2289.
                   ("except" "*" *note expression: 21eb. ["as" *note identifier: 2042.] ":" *note suite: 2289.)+
                   ["else" ":" *note suite: 2289.]
                   ["finally" ":" *note suite: 2289.]
     try3_stmt ::= "try" ":" *note suite: 2289.
                   "finally" ":" *note suite: 2289.

Additional information on exceptions can be found in section *note
Exceptions: 2197, and information on using the *note raise: 5f0.
statement to generate exceptions may be found in section *note The raise
statement: 5f0.

* Menu:

* except clause::
* except* clause::
* else clause::
* finally clause::


File: python.info,  Node: except clause,  Next: except* clause,  Up: The try statement

4.8.4.1 ‘except’ clause
.......................

The ‘except’ clause(s) specify one or more exception handlers.  When no
exception occurs in the *note try: 6ec. clause, no exception handler is
executed.  When an exception occurs in the ‘try’ suite, a search for an
exception handler is started.  This search inspects the ‘except’ clauses
in turn until one is found that matches the exception.  An
expression-less ‘except’ clause, if present, must be last; it matches
any exception.

For an ‘except’ clause with an expression, the expression must evaluate
to an exception type or a tuple of exception types.  The raised
exception matches an ‘except’ clause whose expression evaluates to the
class or a *note non-virtual base class: 11fa. of the exception object,
or to a tuple that contains such a class.

If no ‘except’ clause matches the exception, the search for an exception
handler continues in the surrounding code and on the invocation stack.
(1)

If the evaluation of an expression in the header of an ‘except’ clause
raises an exception, the original search for a handler is canceled and a
search starts for the new exception in the surrounding code and on the
call stack (it is treated as if the entire *note try: 6ec. statement
raised the exception).

When a matching ‘except’ clause is found, the exception is assigned to
the target specified after the ‘as’ keyword in that ‘except’ clause, if
present, and the ‘except’ clause’s suite is executed.  All ‘except’
clauses must have an executable block.  When the end of this block is
reached, execution continues normally after the entire *note try: 6ec.
statement.  (This means that if two nested handlers exist for the same
exception, and the exception occurs in the ‘try’ clause of the inner
handler, the outer handler will not handle the exception.)

When an exception has been assigned using ‘as target’, it is cleared at
the end of the ‘except’ clause.  This is as if

     except E as N:
         foo

was translated to

     except E as N:
         try:
             foo
         finally:
             del N

This means the exception must be assigned to a different name to be able
to refer to it after the ‘except’ clause.  Exceptions are cleared
because with the traceback attached to them, they form a reference cycle
with the stack frame, keeping all locals in that frame alive until the
next garbage collection occurs.

Before an ‘except’ clause’s suite is executed, the exception is stored
in the *note sys: d9. module, where it can be accessed from within the
body of the ‘except’ clause by calling *note sys.exception(): 68e.  When
leaving an exception handler, the exception stored in the ‘sys’ module
is reset to its previous value:

     >>> print(sys.exception())
     None
     >>> try:
     ...     raise TypeError
     ... except:
     ...     print(repr(sys.exception()))
     ...     try:
     ...          raise ValueError
     ...     except:
     ...         print(repr(sys.exception()))
     ...     print(repr(sys.exception()))
     ...
     TypeError()
     ValueError()
     TypeError()
     >>> print(sys.exception())
     None

   ---------- Footnotes ----------

   (1) The exception is propagated to the invocation stack unless there
is a *note finally: 9d5. clause which happens to raise another
exception.  That new exception causes the old one to be lost.


File: python.info,  Node: except* clause,  Next: else clause,  Prev: except clause,  Up: The try statement

4.8.4.2 ‘except*’ clause
........................

The ‘except*’ clause(s) specify one or more handlers for groups of
exceptions (*note BaseExceptionGroup: 25f. instances).  A *note try:
6ec. statement can have either *note except: 18b. or ‘except*’ clauses,
but not both.  The exception type for matching is mandatory in the case
of ‘except*’, so ‘except*:’ is a syntax error.  The type is interpreted
as in the case of ‘except’, but matching is performed on the exceptions
contained in the group that is being handled.  An *note TypeError: 2c3.
is raised if a matching type is a subclass of ‘BaseExceptionGroup’,
because that would have ambiguous semantics.

When an exception group is raised in the try block, each ‘except*’
clause splits (see *note split(): 168f.) it into the subgroups of
matching and non-matching exceptions.  If the matching subgroup is not
empty, it becomes the handled exception (the value returned from *note
sys.exception(): 68e.) and assigned to the target of the ‘except*’
clause (if there is one).  Then, the body of the ‘except*’ clause
executes.  If the non-matching subgroup is not empty, it is processed by
the next ‘except*’ in the same manner.  This continues until all
exceptions in the group have been matched, or the last ‘except*’ clause
has run.

After all ‘except*’ clauses execute, the group of unhandled exceptions
is merged with any exceptions that were raised or re-raised from within
‘except*’ clauses.  This merged exception group propagates on.:

     >>> try:
     ...     raise ExceptionGroup("eg",
     ...         [ValueError(1), TypeError(2), OSError(3), OSError(4)])
     ... except* TypeError as e:
     ...     print(f'caught {type(e)} with nested {e.exceptions}')
     ... except* OSError as e:
     ...     print(f'caught {type(e)} with nested {e.exceptions}')
     ...
     caught <class 'ExceptionGroup'> with nested (TypeError(2),)
     caught <class 'ExceptionGroup'> with nested (OSError(3), OSError(4))
       + Exception Group Traceback (most recent call last):
       |   File "<doctest default[0]>", line 2, in <module>
       |     raise ExceptionGroup("eg",
       |         [ValueError(1), TypeError(2), OSError(3), OSError(4)])
       | ExceptionGroup: eg (1 sub-exception)
       +-+---------------- 1 ----------------
         | ValueError: 1
         +------------------------------------

If the exception raised from the *note try: 6ec. block is not an
exception group and its type matches one of the ‘except*’ clauses, it is
caught and wrapped by an exception group with an empty message string.
This ensures that the type of the target ‘e’ is consistently *note
BaseExceptionGroup: 25f.:

     >>> try:
     ...     raise BlockingIOError
     ... except* BlockingIOError as e:
     ...     print(repr(e))
     ...
     ExceptionGroup('', (BlockingIOError(),))

*note break: abe, *note continue: 9d4. and *note return: 9d9. cannot
appear in an ‘except*’ clause.


File: python.info,  Node: else clause,  Next: finally clause,  Prev: except* clause,  Up: The try statement

4.8.4.3 ‘else’ clause
.....................

The optional ‘else’ clause is executed if the control flow leaves the
*note try: 6ec. suite, no exception was raised, and no *note return:
9d9, *note continue: 9d4, or *note break: abe. statement was executed.
Exceptions in the ‘else’ clause are not handled by the preceding *note
except: 18b. clauses.


File: python.info,  Node: finally clause,  Prev: else clause,  Up: The try statement

4.8.4.4 ‘finally’ clause
........................

If ‘finally’ is present, it specifies a ‘cleanup’ handler.  The *note
try: 6ec. clause is executed, including any *note except: 18b. and *note
else: 2296. clauses.  If an exception occurs in any of the clauses and
is not handled, the exception is temporarily saved.  The ‘finally’
clause is executed.  If there is a saved exception it is re-raised at
the end of the ‘finally’ clause.  If the ‘finally’ clause raises another
exception, the saved exception is set as the context of the new
exception.  If the ‘finally’ clause executes a *note return: 9d9, *note
break: abe. or *note continue: 9d4. statement, the saved exception is
discarded:

     >>> def f():
     ...     try:
     ...         1/0
     ...     finally:
     ...         return 42
     ...
     >>> f()
     42

The exception information is not available to the program during
execution of the ‘finally’ clause.

When a *note return: 9d9, *note break: abe. or *note continue: 9d4.
statement is executed in the *note try: 6ec. suite of a ‘try’…‘finally’
statement, the ‘finally’ clause is also executed ‘on the way out.’

The return value of a function is determined by the last *note return:
9d9. statement executed.  Since the ‘finally’ clause always executes, a
‘return’ statement executed in the ‘finally’ clause will always be the
last one executed:

     >>> def foo():
     ...     try:
     ...         return 'try'
     ...     finally:
     ...         return 'finally'
     ...
     >>> foo()
     'finally'

Changed in version 3.8: Prior to Python 3.8, a *note continue: 9d4.
statement was illegal in the ‘finally’ clause due to a problem with the
implementation.


File: python.info,  Node: The with statement,  Next: The match statement,  Prev: The try statement,  Up: Compound statements

4.8.5 The ‘with’ statement
--------------------------

The *note with: 5d5. statement is used to wrap the execution of a block
with methods defined by a context manager (see section *note With
Statement Context Managers: 20e4.).  This allows common *note try:
6ec.…*note except: 18b.…*note finally: 9d5. usage patterns to be
encapsulated for convenient reuse.

     with_stmt          ::= "with" ( "(" *note with_stmt_contents: 229a. ","? ")" | *note with_stmt_contents: 229a. ) ":" *note suite: 2289.
     with_stmt_contents ::= *note with_item: 229b. ("," *note with_item: 229b.)*
     with_item          ::= *note expression: 21eb. ["as" *note target: 225e.]

The execution of the *note with: 5d5. statement with one “item” proceeds
as follows:

  1. The context expression (the expression given in the *note
     with_item: 229b.) is evaluated to obtain a context manager.

  2. The context manager’s *note __enter__(): 5cb. is loaded for later
     use.

  3. The context manager’s *note __exit__(): 1349. is loaded for later
     use.

  4. The context manager’s *note __enter__(): 5cb. method is invoked.

  5. If a target was included in the *note with: 5d5. statement, the
     return value from *note __enter__(): 5cb. is assigned to it.

          Note: The *note with: 5d5. statement guarantees that if the
          *note __enter__(): 5cb. method returns without an error, then
          *note __exit__(): 1349. will always be called.  Thus, if an
          error occurs during the assignment to the target list, it will
          be treated the same as an error occurring within the suite
          would be.  See step 7 below.

  6. The suite is executed.

  7. The context manager’s *note __exit__(): 1349. method is invoked.
     If an exception caused the suite to be exited, its type, value, and
     traceback are passed as arguments to ‘__exit__()’.  Otherwise,
     three *note None: 678. arguments are supplied.

     If the suite was exited due to an exception, and the return value
     from the *note __exit__(): 1349. method was false, the exception is
     reraised.  If the return value was true, the exception is
     suppressed, and execution continues with the statement following
     the *note with: 5d5. statement.

     If the suite was exited for any reason other than an exception, the
     return value from *note __exit__(): 1349. is ignored, and execution
     proceeds at the normal location for the kind of exit that was
     taken.

The following code:

     with EXPRESSION as TARGET:
         SUITE

is semantically equivalent to:

     manager = (EXPRESSION)
     enter = manager.__enter__
     exit = manager.__exit__
     value = enter()
     hit_except = False

     try:
         TARGET = value
         SUITE
     except:
         hit_except = True
         if not exit(*sys.exc_info()):
             raise
     finally:
         if not hit_except:
             exit(None, None, None)

except that implicit *note special method lookup: 2117. is used for
*note __enter__(): 5cb. and *note __exit__(): 1349.

With more than one item, the context managers are processed as if
multiple *note with: 5d5. statements were nested:

     with A() as a, B() as b:
         SUITE

is semantically equivalent to:

     with A() as a:
         with B() as b:
             SUITE

You can also write multi-item context managers in multiple lines if the
items are surrounded by parentheses.  For example:

     with (
         A() as a,
         B() as b,
     ):
         SUITE

Changed in version 3.1: Support for multiple context expressions.

Changed in version 3.10: Support for using grouping parentheses to break
the statement in multiple lines.

See also
........

PEP 343(1) - The “with” statement

     The specification, background, and examples for the Python *note
     with: 5d5. statement.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0343/


File: python.info,  Node: The match statement,  Next: Function definitions,  Prev: The with statement,  Up: Compound statements

4.8.6 The ‘match’ statement
---------------------------

Added in version 3.10.

The match statement is used for pattern matching.  Syntax:

     match_stmt   ::= 'match' *note subject_expr: 229e. ":" NEWLINE INDENT *note case_block: 229f.+ DEDENT
     subject_expr ::= `!star_named_expression` "," `!star_named_expressions`?
                      | `!named_expression`
     case_block   ::= 'case' *note patterns: 22a0. [*note guard: 22a1.] ":" `!block`

     Note: This section uses single quotes to denote *note soft
     keywords: 812.

Pattern matching takes a pattern as input (following ‘case’) and a
subject value (following ‘match’).  The pattern (which may contain
subpatterns) is matched against the subject value.  The outcomes are:

   * A match success or failure (also termed a pattern success or
     failure).

   * Possible binding of matched values to a name.  The prerequisites
     for this are further discussed below.

The ‘match’ and ‘case’ keywords are *note soft keywords: 812.

See also
........

   * PEP 634(1) – Structural Pattern Matching: Specification

   * PEP 636(2) – Structural Pattern Matching: Tutorial

* Menu:

* Overview::
* Guards::
* Irrefutable Case Blocks::
* Patterns::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/

   (2) https://peps.python.org/pep-0636/


File: python.info,  Node: Overview,  Next: Guards,  Up: The match statement

4.8.6.1 Overview
................

Here’s an overview of the logical flow of a match statement:

  1. The subject expression ‘subject_expr’ is evaluated and a resulting
     subject value obtained.  If the subject expression contains a
     comma, a tuple is constructed using *note the standard rules: 22a3.

  2. Each pattern in a ‘case_block’ is attempted to match with the
     subject value.  The specific rules for success or failure are
     described below.  The match attempt can also bind some or all of
     the standalone names within the pattern.  The precise pattern
     binding rules vary per pattern type and are specified below.  'Name
     bindings made during a successful pattern match outlive the
     executed block and can be used after the match statement'.

          Note: During failed pattern matches, some subpatterns may
          succeed.  Do not rely on bindings being made for a failed
          match.  Conversely, do not rely on variables remaining
          unchanged after a failed match.  The exact behavior is
          dependent on implementation and may vary.  This is an
          intentional decision made to allow different implementations
          to add optimizations.

  3. If the pattern succeeds, the corresponding guard (if present) is
     evaluated.  In this case all name bindings are guaranteed to have
     happened.

        * If the guard evaluates as true or is missing, the ‘block’
          inside ‘case_block’ is executed.

        * Otherwise, the next ‘case_block’ is attempted as described
          above.

        * If there are no further case blocks, the match statement is
          completed.

     Note: Users should generally never rely on a pattern being
     evaluated.  Depending on implementation, the interpreter may cache
     values or use other optimizations which skip repeated evaluations.

A sample match statement:

     >>> flag = False
     >>> match (100, 200):
     ...    case (100, 300):  # Mismatch: 200 != 300
     ...        print('Case 1')
     ...    case (100, 200) if flag:  # Successful match, but guard fails
     ...        print('Case 2')
     ...    case (100, y):  # Matches and binds y to 200
     ...        print(f'Case 3, y: {y}')
     ...    case _:  # Pattern not attempted
     ...        print('Case 4, I match anything!')
     ...
     Case 3, y: 200

In this case, ‘if flag’ is a guard.  Read more about that in the next
section.


File: python.info,  Node: Guards,  Next: Irrefutable Case Blocks,  Prev: Overview,  Up: The match statement

4.8.6.2 Guards
..............

     guard ::= "if" `!named_expression`

A ‘guard’ (which is part of the ‘case’) must succeed for code inside the
‘case’ block to execute.  It takes the form: *note if: 2f3. followed by
an expression.

The logical flow of a ‘case’ block with a ‘guard’ follows:

  1. Check that the pattern in the ‘case’ block succeeded.  If the
     pattern failed, the ‘guard’ is not evaluated and the next ‘case’
     block is checked.

  2. If the pattern succeeded, evaluate the ‘guard’.

        * If the ‘guard’ condition evaluates as true, the case block is
          selected.

        * If the ‘guard’ condition evaluates as false, the case block is
          not selected.

        * If the ‘guard’ raises an exception during evaluation, the
          exception bubbles up.

Guards are allowed to have side effects as they are expressions.  Guard
evaluation must proceed from the first to the last case block, one at a
time, skipping case blocks whose pattern(s) don’t all succeed.  (I.e.,
guard evaluation must happen in order.)  Guard evaluation must stop once
a case block is selected.


File: python.info,  Node: Irrefutable Case Blocks,  Next: Patterns,  Prev: Guards,  Up: The match statement

4.8.6.3 Irrefutable Case Blocks
...............................

An irrefutable case block is a match-all case block.  A match statement
may have at most one irrefutable case block, and it must be last.

A case block is considered irrefutable if it has no guard and its
pattern is irrefutable.  A pattern is considered irrefutable if we can
prove from its syntax alone that it will always succeed.  Only the
following patterns are irrefutable:

   * *note AS Patterns: 22a7. whose left-hand side is irrefutable

   * *note OR Patterns: 22a8. containing at least one irrefutable
     pattern

   * *note Capture Patterns: 22a9.

   * *note Wildcard Patterns: 814.

   * parenthesized irrefutable patterns


File: python.info,  Node: Patterns,  Prev: Irrefutable Case Blocks,  Up: The match statement

4.8.6.4 Patterns
................

     Note: This section uses grammar notations beyond standard EBNF:

        * the notation ‘SEP.RULE+’ is shorthand for ‘RULE (SEP RULE)*’

        * the notation ‘!RULE’ is shorthand for a negative lookahead
          assertion

The top-level syntax for ‘patterns’ is:

     patterns       ::= *note open_sequence_pattern: 22ab. | *note pattern: 22ac.
     pattern        ::= *note as_pattern: 22ad. | *note or_pattern: 22ae.
     closed_pattern ::= | *note literal_pattern: 22b0.
                        | *note capture_pattern: 22b1.
                        | *note wildcard_pattern: 22b2.
                        | *note value_pattern: 22b3.
                        | *note group_pattern: 22b4.
                        | *note sequence_pattern: 22b5.
                        | *note mapping_pattern: 22b6.
                        | *note class_pattern: 22b7.

The descriptions below will include a description “in simple terms” of
what a pattern does for illustration purposes (credits to Raymond
Hettinger for a document that inspired most of the descriptions).  Note
that these descriptions are purely for illustration purposes and 'may
not' reflect the underlying implementation.  Furthermore, they do not
cover all valid forms.

* Menu:

* OR Patterns::
* AS Patterns::
* Literal Patterns::
* Capture Patterns::
* Wildcard Patterns::
* Value Patterns::
* Group Patterns::
* Sequence Patterns::
* Mapping Patterns::
* Class Patterns::


File: python.info,  Node: OR Patterns,  Next: AS Patterns,  Up: Patterns

4.8.6.5 OR Patterns
...................

An OR pattern is two or more patterns separated by vertical bars ‘|’.
Syntax:

     or_pattern ::= "|".*note closed_pattern: 22af.+

Only the final subpattern may be *note irrefutable: 22a5, and each
subpattern must bind the same set of names to avoid ambiguity.

An OR pattern matches each of its subpatterns in turn to the subject
value, until one succeeds.  The OR pattern is then considered
successful.  Otherwise, if none of the subpatterns succeed, the OR
pattern fails.

In simple terms, ‘P1 | P2 | ...’ will try to match ‘P1’, if it fails it
will try to match ‘P2’, succeeding immediately if any succeeds, failing
otherwise.


File: python.info,  Node: AS Patterns,  Next: Literal Patterns,  Prev: OR Patterns,  Up: Patterns

4.8.6.6 AS Patterns
...................

An AS pattern matches an OR pattern on the left of the *note as: 2298.
keyword against a subject.  Syntax:

     as_pattern ::= *note or_pattern: 22ae. "as" *note capture_pattern: 22b1.

If the OR pattern fails, the AS pattern fails.  Otherwise, the AS
pattern binds the subject to the name on the right of the as keyword and
succeeds.  ‘capture_pattern’ cannot be a ‘_’.

In simple terms ‘P as NAME’ will match with ‘P’, and on success it will
set ‘NAME = <subject>’.


File: python.info,  Node: Literal Patterns,  Next: Capture Patterns,  Prev: AS Patterns,  Up: Patterns

4.8.6.7 Literal Patterns
........................

A literal pattern corresponds to most *note literals: 204e. in Python.
Syntax:

     literal_pattern ::= *note signed_number: 22bc.
                         | *note signed_number: 22bc. "+" NUMBER
                         | *note signed_number: 22bc. "-" NUMBER
                         | `!strings`
                         | "None"
                         | "True"
                         | "False"
     signed_number   ::= ["-"] NUMBER

The rule ‘strings’ and the token ‘NUMBER’ are defined in the *note
standard Python grammar: 22bd.  Triple-quoted strings are supported.
Raw strings and byte strings are supported.  *note f-strings: 9b4. are
not supported.

The forms ‘signed_number '+' NUMBER’ and ‘signed_number '-' NUMBER’ are
for expressing *note complex numbers: 2087.; they require a real number
on the left and an imaginary number on the right.  E.g.  ‘3 + 4j’.

In simple terms, ‘LITERAL’ will succeed only if ‘<subject> == LITERAL’.
For the singletons ‘None’, ‘True’ and ‘False’, the *note is: 2f5.
operator is used.


File: python.info,  Node: Capture Patterns,  Next: Wildcard Patterns,  Prev: Literal Patterns,  Up: Patterns

4.8.6.8 Capture Patterns
........................

A capture pattern binds the subject value to a name.  Syntax:

     capture_pattern ::= !'_' NAME

A single underscore ‘_’ is not a capture pattern (this is what ‘!'_'’
expresses).  It is instead treated as a *note wildcard_pattern: 22b2.

In a given pattern, a given name can only be bound once.  E.g.  ‘case x,
x: ...’ is invalid while ‘case [x] | x: ...’ is allowed.

Capture patterns always succeed.  The binding follows scoping rules
established by the assignment expression operator in PEP 572(1); the
name becomes a local variable in the closest containing function scope
unless there’s an applicable *note global: 18a. or *note nonlocal: 12ef.
statement.

In simple terms ‘NAME’ will always succeed and it will set ‘NAME =
<subject>’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0572/


File: python.info,  Node: Wildcard Patterns,  Next: Value Patterns,  Prev: Capture Patterns,  Up: Patterns

4.8.6.9 Wildcard Patterns
.........................

A wildcard pattern always succeeds (matches anything) and binds no name.
Syntax:

     wildcard_pattern ::= '_'

‘_’ is a *note soft keyword: 812. within any pattern, but only within
patterns.  It is an identifier, as usual, even within ‘match’ subject
expressions, ‘guard’s, and ‘case’ blocks.

In simple terms, ‘_’ will always succeed.


File: python.info,  Node: Value Patterns,  Next: Group Patterns,  Prev: Wildcard Patterns,  Up: Patterns

4.8.6.10 Value Patterns
.......................

A value pattern represents a named value in Python.  Syntax:

     value_pattern ::= *note attr: 22c2.
     attr          ::= *note name_or_attr: 22c3. "." NAME
     name_or_attr  ::= *note attr: 22c2. | NAME

The dotted name in the pattern is looked up using standard Python *note
name resolution rules: 218e.  The pattern succeeds if the value found
compares equal to the subject value (using the ‘==’ equality operator).

In simple terms ‘NAME1.NAME2’ will succeed only if ‘<subject> ==
NAME1.NAME2’

     Note: If the same value occurs multiple times in the same match
     statement, the interpreter may cache the first value found and
     reuse it rather than repeat the same lookup.  This cache is
     strictly tied to a given execution of a given match statement.


File: python.info,  Node: Group Patterns,  Next: Sequence Patterns,  Prev: Value Patterns,  Up: Patterns

4.8.6.11 Group Patterns
.......................

A group pattern allows users to add parentheses around patterns to
emphasize the intended grouping.  Otherwise, it has no additional
syntax.  Syntax:

     group_pattern ::= "(" *note pattern: 22ac. ")"

In simple terms ‘(P)’ has the same effect as ‘P’.


File: python.info,  Node: Sequence Patterns,  Next: Mapping Patterns,  Prev: Group Patterns,  Up: Patterns

4.8.6.12 Sequence Patterns
..........................

A sequence pattern contains several subpatterns to be matched against
sequence elements.  The syntax is similar to the unpacking of a list or
tuple.

     sequence_pattern       ::= "[" [*note maybe_sequence_pattern: 22c8.] "]"
                                | "(" [*note open_sequence_pattern: 22ab.] ")"
     open_sequence_pattern  ::= *note maybe_star_pattern: 22c9. "," [*note maybe_sequence_pattern: 22c8.]
     maybe_sequence_pattern ::= ",".*note maybe_star_pattern: 22c9.+ ","?
     maybe_star_pattern     ::= *note star_pattern: 22ca. | *note pattern: 22ac.
     star_pattern           ::= "*" (*note capture_pattern: 22b1. | *note wildcard_pattern: 22b2.)

There is no difference if parentheses or square brackets are used for
sequence patterns (i.e.  ‘(...)’ vs ‘[...]’ ).

     Note: A single pattern enclosed in parentheses without a trailing
     comma (e.g.  ‘(3 | 4)’) is a *note group pattern: 22c4.  While a
     single pattern enclosed in square brackets (e.g.  ‘[3 | 4]’) is
     still a sequence pattern.

At most one star subpattern may be in a sequence pattern.  The star
subpattern may occur in any position.  If no star subpattern is present,
the sequence pattern is a fixed-length sequence pattern; otherwise it is
a variable-length sequence pattern.

The following is the logical flow for matching a sequence pattern
against a subject value:

  1. If the subject value is not a sequence (1), the sequence pattern
     fails.

  2. If the subject value is an instance of ‘str’, ‘bytes’ or
     ‘bytearray’ the sequence pattern fails.

  3. The subsequent steps depend on whether the sequence pattern is
     fixed or variable-length.

     If the sequence pattern is fixed-length:

       1. If the length of the subject sequence is not equal to the
          number of subpatterns, the sequence pattern fails

       2. Subpatterns in the sequence pattern are matched to their
          corresponding items in the subject sequence from left to
          right.  Matching stops as soon as a subpattern fails.  If all
          subpatterns succeed in matching their corresponding item, the
          sequence pattern succeeds.

     Otherwise, if the sequence pattern is variable-length:

       1. If the length of the subject sequence is less than the number
          of non-star subpatterns, the sequence pattern fails.

       2. The leading non-star subpatterns are matched to their
          corresponding items as for fixed-length sequences.

       3. If the previous step succeeds, the star subpattern matches a
          list formed of the remaining subject items, excluding the
          remaining items corresponding to non-star subpatterns
          following the star subpattern.

       4. Remaining non-star subpatterns are matched to their
          corresponding subject items, as for a fixed-length sequence.

          Note: The length of the subject sequence is obtained via *note
          len(): 631. (i.e.  via the *note __len__(): 15da. protocol).
          This length may be cached by the interpreter in a similar
          manner as *note value patterns: 22c1.

In simple terms ‘[P1, P2, P3,’ … ‘, P<N>]’ matches only if all the
following happens:

   * check ‘<subject>’ is a sequence

   * ‘len(subject) == <N>’

   * ‘P1’ matches ‘<subject>[0]’ (note that this match can also bind
     names)

   * ‘P2’ matches ‘<subject>[1]’ (note that this match can also bind
     names)

   * … and so on for the corresponding pattern/element.

   ---------- Footnotes ----------

   (1) In pattern matching, a sequence is defined as one of the
following:

   * a class that inherits from *note collections.abc.Sequence: 1209.

   * a Python class that has been registered as *note
     collections.abc.Sequence: 1209.

   * a builtin class that has its (CPython) *note Py_TPFLAGS_SEQUENCE:
     19ff. bit set

   * a class that inherits from any of the above

The following standard library classes are sequences:

   * *note array.array: 1a0.

   * *note collections.deque: 5df.

   * *note list: 614.

   * *note memoryview: 2eb.

   * *note range: 94d.

   * *note tuple: 373.

     Note: Subject values of type ‘str’, ‘bytes’, and ‘bytearray’ do not
     match sequence patterns.


File: python.info,  Node: Mapping Patterns,  Next: Class Patterns,  Prev: Sequence Patterns,  Up: Patterns

4.8.6.13 Mapping Patterns
.........................

A mapping pattern contains one or more key-value patterns.  The syntax
is similar to the construction of a dictionary.  Syntax:

     mapping_pattern     ::= "{" [*note items_pattern: 22cd.] "}"
     items_pattern       ::= ",".*note key_value_pattern: 22ce.+ ","?
     key_value_pattern   ::= (*note literal_pattern: 22b0. | *note value_pattern: 22b3.) ":" *note pattern: 22ac.
                             | *note double_star_pattern: 22cf.
     double_star_pattern ::= "**" *note capture_pattern: 22b1.

At most one double star pattern may be in a mapping pattern.  The double
star pattern must be the last subpattern in the mapping pattern.

Duplicate keys in mapping patterns are disallowed.  Duplicate literal
keys will raise a *note SyntaxError: 18d.  Two keys that otherwise have
the same value will raise a *note ValueError: 202. at runtime.

The following is the logical flow for matching a mapping pattern against
a subject value:

  1. If the subject value is not a mapping (1),the mapping pattern
     fails.

  2. If every key given in the mapping pattern is present in the subject
     mapping, and the pattern for each key matches the corresponding
     item of the subject mapping, the mapping pattern succeeds.

  3. If duplicate keys are detected in the mapping pattern, the pattern
     is considered invalid.  A *note SyntaxError: 18d. is raised for
     duplicate literal values; or a *note ValueError: 202. for named
     keys of the same value.

     Note: Key-value pairs are matched using the two-argument form of
     the mapping subject’s ‘get()’ method.  Matched key-value pairs must
     already be present in the mapping, and not created on-the-fly via
     *note __missing__(): 1202. or *note __getitem__(): 283.

In simple terms ‘{KEY1: P1, KEY2: P2, ... }’ matches only if all the
following happens:

   * check ‘<subject>’ is a mapping

   * ‘KEY1 in <subject>’

   * ‘P1’ matches ‘<subject>[KEY1]’

   * … and so on for the corresponding KEY/pattern pair.

   ---------- Footnotes ----------

   (1) In pattern matching, a mapping is defined as one of the
following:

   * a class that inherits from *note collections.abc.Mapping: 8d3.

   * a Python class that has been registered as *note
     collections.abc.Mapping: 8d3.

   * a builtin class that has its (CPython) *note Py_TPFLAGS_MAPPING:
     19fe. bit set

   * a class that inherits from any of the above

The standard library classes *note dict: 256. and *note
types.MappingProxyType: 470. are mappings.


File: python.info,  Node: Class Patterns,  Prev: Mapping Patterns,  Up: Patterns

4.8.6.14 Class Patterns
.......................

A class pattern represents a class and its positional and keyword
arguments (if any).  Syntax:

     class_pattern       ::= *note name_or_attr: 22c3. "(" [*note pattern_arguments: 22d2. ","?] ")"
     pattern_arguments   ::= *note positional_patterns: 22d3. ["," *note keyword_patterns: 22d4.]
                             | *note keyword_patterns: 22d4.
     positional_patterns ::= ",".*note pattern: 22ac.+
     keyword_patterns    ::= ",".*note keyword_pattern: 22d5.+
     keyword_pattern     ::= NAME "=" *note pattern: 22ac.

The same keyword should not be repeated in class patterns.

The following is the logical flow for matching a class pattern against a
subject value:

  1. If ‘name_or_attr’ is not an instance of the builtin *note type:
     d71. , raise *note TypeError: 2c3.

  2. If the subject value is not an instance of ‘name_or_attr’ (tested
     via *note isinstance(): 445.), the class pattern fails.

  3. If no pattern arguments are present, the pattern succeeds.
     Otherwise, the subsequent steps depend on whether keyword or
     positional argument patterns are present.

     For a number of built-in types (specified below), a single
     positional subpattern is accepted which will match the entire
     subject; for these types keyword patterns also work as for other
     types.

     If only keyword patterns are present, they are processed as
     follows, one by one:

       1. The keyword is looked up as an attribute on the subject.

             * If this raises an exception other than *note
               AttributeError: 34e, the exception bubbles up.

             * If this raises *note AttributeError: 34e, the class
               pattern has failed.

             * Else, the subpattern associated with the keyword pattern
               is matched against the subject’s attribute value.  If
               this fails, the class pattern fails; if this succeeds,
               the match proceeds to the next keyword.

       2. If all keyword patterns succeed, the class pattern succeeds.

     If any positional patterns are present, they are converted to
     keyword patterns using the *note __match_args__: 1a1c. attribute on
     the class ‘name_or_attr’ before matching:

       1. The equivalent of ‘getattr(cls, "__match_args__", ())’ is
          called.

             * If this raises an exception, the exception bubbles up.

             * If the returned value is not a tuple, the conversion
               fails and *note TypeError: 2c3. is raised.

             * If there are more positional patterns than
               ‘len(cls.__match_args__)’, *note TypeError: 2c3. is
               raised.

             * Otherwise, positional pattern ‘i’ is converted to a
               keyword pattern using ‘__match_args__[i]’ as the keyword.
               ‘__match_args__[i]’ must be a string; if not *note
               TypeError: 2c3. is raised.

             * If there are duplicate keywords, *note TypeError: 2c3. is
               raised.

          See also
          ........

          *note Customizing positional arguments in class pattern
          matching: 2172.

       2. Once all positional patterns have been converted to keyword
          patterns, the match proceeds as if there were only keyword
          patterns.

     For the following built-in types the handling of positional
     subpatterns is different:

        * *note bool: 46b.

        * *note bytearray: 2ea.

        * *note bytes: 1c2.

        * *note dict: 256.

        * *note float: 2f7.

        * *note frozenset: 5dd.

        * *note int: 257.

        * *note list: 614.

        * *note set: 5dc.

        * *note str: 44f.

        * *note tuple: 373.

     These classes accept a single positional argument, and the pattern
     there is matched against the whole object rather than an attribute.
     For example ‘int(0|1)’ matches the value ‘0’, but not the value
     ‘0.0’.

In simple terms ‘CLS(P1, attr=P2)’ matches only if the following
happens:

   * ‘isinstance(<subject>, CLS)’

   * convert ‘P1’ to a keyword pattern using ‘CLS.__match_args__’

   * For each keyword argument ‘attr=P2’:

        * ‘hasattr(<subject>, "attr")’

        * ‘P2’ matches ‘<subject>.attr’

   * … and so on for the corresponding keyword argument/pattern pair.

See also
........

   * PEP 634(1) – Structural Pattern Matching: Specification

   * PEP 636(2) – Structural Pattern Matching: Tutorial

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/

   (2) https://peps.python.org/pep-0636/


File: python.info,  Node: Function definitions,  Next: Class definitions,  Prev: The match statement,  Up: Compound statements

4.8.7 Function definitions
--------------------------

A function definition defines a user-defined function object (see
section *note The standard type hierarchy: 2094.):

     funcdef                   ::= [*note decorators: 22d7.] "def" *note funcname: 22d8. [*note type_params: 2278.] "(" [*note parameter_list: 223c.] ")"
                                   ["->" *note expression: 21eb.] ":" *note suite: 2289.
     decorators                ::= *note decorator: 22d9.+
     decorator                 ::= "@" *note assignment_expression: 2191. NEWLINE
     parameter_list            ::= *note defparameter: 22da. ("," *note defparameter: 22da.)* "," "/" ["," [*note parameter_list_no_posonly: 22db.]]
                                   | *note parameter_list_no_posonly: 22db.
     parameter_list_no_posonly ::= *note defparameter: 22da. ("," *note defparameter: 22da.)* ["," [*note parameter_list_starargs: 22dc.]]
                                   | *note parameter_list_starargs: 22dc.
     parameter_list_starargs   ::= "*" [*note star_parameter: 22dd.] ("," *note defparameter: 22da.)* ["," [*note parameter_star_kwargs: 22de.]]
                                   | "*" ("," *note defparameter: 22da.)+ ["," [*note parameter_star_kwargs: 22de.]]
                                   | *note parameter_star_kwargs: 22de.
     parameter_star_kwargs     ::= "**" *note parameter: 22df. [","]
     parameter                 ::= *note identifier: 2042. [":" *note expression: 21eb.]
     star_parameter            ::= *note identifier: 2042. [":" ["*"] *note expression: 21eb.]
     defparameter              ::= *note parameter: 22df. ["=" *note expression: 21eb.]
     funcname                  ::= *note identifier: 2042.

A function definition is an executable statement.  Its execution binds
the function name in the current local namespace to a function object (a
wrapper around the executable code for the function).  This function
object contains a reference to the current global namespace as the
global namespace to be used when the function is called.

The function definition does not execute the function body; this gets
executed only when the function is called.  (1)

A function definition may be wrapped by one or more *note decorator:
734. expressions.  Decorator expressions are evaluated when the function
is defined, in the scope that contains the function definition.  The
result must be a callable, which is invoked with the function object as
the only argument.  The returned value is bound to the function name
instead of the function object.  Multiple decorators are applied in
nested fashion.  For example, the following code

     @f1(arg)
     @f2
     def func(): pass

is roughly equivalent to

     def func(): pass
     func = f1(arg)(f2(func))

except that the original function is not temporarily bound to the name
‘func’.

Changed in version 3.9: Functions may be decorated with any valid *note
assignment_expression: 2191.  Previously, the grammar was much more
restrictive; see PEP 614(2) for details.

A list of *note type parameters: 2b3. may be given in square brackets
between the function’s name and the opening parenthesis for its
parameter list.  This indicates to static type checkers that the
function is generic.  At runtime, the type parameters can be retrieved
from the function’s *note __type_params__: 20af. attribute.  See *note
Generic functions: 456. for more.

Changed in version 3.12: Type parameter lists are new in Python 3.12.

When one or more *note parameters: 20ae. have the form 'parameter' ‘=’
'expression', the function is said to have “default parameter values.”
For a parameter with a default value, the corresponding *note argument:
44c. may be omitted from a call, in which case the parameter’s default
value is substituted.  If a parameter has a default value, all following
parameters up until the “‘*’” must also have a default value — this is a
syntactic restriction that is not expressed by the grammar.

'Default parameter values are evaluated from left to right when the
function definition is executed.'  This means that the expression is
evaluated once, when the function is defined, and that the same
“pre-computed” value is used for each call.  This is especially
important to understand when a default parameter value is a mutable
object, such as a list or a dictionary: if the function modifies the
object (e.g.  by appending an item to a list), the default parameter
value is in effect modified.  This is generally not what was intended.
A way around this is to use ‘None’ as the default, and explicitly test
for it in the body of the function, e.g.:

     def whats_on_the_telly(penguin=None):
         if penguin is None:
             penguin = []
         penguin.append("property of the zoo")
         return penguin

Function call semantics are described in more detail in section *note
Calls: dab.  A function call always assigns values to all parameters
mentioned in the parameter list, either from positional arguments, from
keyword arguments, or from default values.  If the form “‘*identifier’”
is present, it is initialized to a tuple receiving any excess positional
parameters, defaulting to the empty tuple.  If the form “‘**identifier’”
is present, it is initialized to a new ordered mapping receiving any
excess keyword arguments, defaulting to a new empty mapping of the same
type.  Parameters after “‘*’” or “‘*identifier’” are keyword-only
parameters and may only be passed by keyword arguments.  Parameters
before “‘/’” are positional-only parameters and may only be passed by
positional arguments.

Changed in version 3.8: The ‘/’ function parameter syntax may be used to
indicate positional-only parameters.  See PEP 570(3) for details.

Parameters may have an *note annotation: 1dcf. of the form “‘:
expression’” following the parameter name.  Any parameter may have an
annotation, even those of the form ‘*identifier’ or ‘**identifier’.  (As
a special case, parameters of the form ‘*identifier’ may have an
annotation “‘: *expression’”.)  Functions may have “return” annotation
of the form “‘-> expression’” after the parameter list.  These
annotations can be any valid Python expression.  The presence of
annotations does not change the semantics of a function.  The annotation
values are available as values of a dictionary keyed by the parameters’
names in the ‘__annotations__’ attribute of the function object.  If the
‘annotations’ import from *note __future__: 0. is used, annotations are
preserved as strings at runtime which enables postponed evaluation.
Otherwise, they are evaluated when the function definition is executed.
In this case annotations may be evaluated in a different order than they
appear in the source code.

Changed in version 3.11: Parameters of the form “‘*identifier’” may have
an annotation “‘: *expression’”.  See PEP 646(4).

It is also possible to create anonymous functions (functions not bound
to a name), for immediate use in expressions.  This uses lambda
expressions, described in section *note Lambdas: 12e4.  Note that the
lambda expression is merely a shorthand for a simplified function
definition; a function defined in a “*note def: 14a9.” statement can be
passed around or assigned to another name just like a function defined
by a lambda expression.  The “‘def’” form is actually more powerful
since it allows the execution of multiple statements and annotations.

'Programmer’s note:' Functions are first-class objects.  A “‘def’”
statement executed inside a function definition defines a local function
that can be returned or passed around.  Free variables used in the
nested function can access the local variables of the function
containing the def.  See section *note Naming and binding: 20a9. for
details.

See also
........

PEP 3107(5) - Function Annotations

     The original specification for function annotations.

PEP 484(6) - Type Hints

     Definition of a standard meaning for annotations: type hints.

PEP 526(7) - Syntax for Variable Annotations

     Ability to type hint variable declarations, including class
     variables and instance variables.

PEP 563(8) - Postponed Evaluation of Annotations

     Support for forward references within annotations by preserving
     annotations in a string form at runtime instead of eager
     evaluation.

PEP 318(9) - Decorators for Functions and Methods

     Function and method decorators were introduced.  Class decorators
     were introduced in PEP 3129(10).

   ---------- Footnotes ----------

   (1) A string literal appearing as the first statement in the function
body is transformed into the function’s *note __doc__: 121e. attribute
and therefore the function’s *note docstring: 22e0.

   (2) https://peps.python.org/pep-0614/

   (3) https://peps.python.org/pep-0570/

   (4) https://peps.python.org/pep-0646/

   (5) https://peps.python.org/pep-3107/

   (6) https://peps.python.org/pep-0484/

   (7) https://peps.python.org/pep-0526/

   (8) https://peps.python.org/pep-0563/

   (9) https://peps.python.org/pep-0318/

   (10) https://peps.python.org/pep-3129/


File: python.info,  Node: Class definitions,  Next: Coroutines<2>,  Prev: Function definitions,  Up: Compound statements

4.8.8 Class definitions
-----------------------

A class definition defines a class object (see section *note The
standard type hierarchy: 2094.):

     classdef    ::= [*note decorators: 22d7.] "class" *note classname: 22e2. [*note type_params: 2278.] [*note inheritance: 22e3.] ":" *note suite: 2289.
     inheritance ::= "(" [*note argument_list: 220e.] ")"
     classname   ::= *note identifier: 2042.

A class definition is an executable statement.  The inheritance list
usually gives a list of base classes (see *note Metaclasses: 2124. for
more advanced uses), so each item in the list should evaluate to a class
object which allows subclassing.  Classes without an inheritance list
inherit, by default, from the base class *note object: a9b.; hence,

     class Foo:
         pass

is equivalent to

     class Foo(object):
         pass

The class’s suite is then executed in a new execution frame (see *note
Naming and binding: 20a9.), using a newly created local namespace and
the original global namespace.  (Usually, the suite contains mostly
function definitions.)  When the class’s suite finishes execution, its
execution frame is discarded but its local namespace is saved.  (1)  A
class object is then created using the inheritance list for the base
classes and the saved local namespace for the attribute dictionary.  The
class name is bound to this class object in the original local
namespace.

The order in which attributes are defined in the class body is preserved
in the new class’s *note __dict__: c7e.  Note that this is reliable only
right after the class is created and only for classes that were defined
using the definition syntax.

Class creation can be customized heavily using *note metaclasses: 2124.

Classes can also be decorated: just like when decorating functions,

     @f1(arg)
     @f2
     class Foo: pass

is roughly equivalent to

     class Foo: pass
     Foo = f1(arg)(f2(Foo))

The evaluation rules for the decorator expressions are the same as for
function decorators.  The result is then bound to the class name.

Changed in version 3.9: Classes may be decorated with any valid *note
assignment_expression: 2191.  Previously, the grammar was much more
restrictive; see PEP 614(2) for details.

A list of *note type parameters: 2b3. may be given in square brackets
immediately after the class’s name.  This indicates to static type
checkers that the class is generic.  At runtime, the type parameters can
be retrieved from the class’s *note __type_params__: 20d9. attribute.
See *note Generic classes: 455. for more.

Changed in version 3.12: Type parameter lists are new in Python 3.12.

'Programmer’s note:' Variables defined in the class definition are class
attributes; they are shared by instances.  Instance attributes can be
set in a method with ‘self.name = value’.  Both class and instance
attributes are accessible through the notation “‘self.name’”, and an
instance attribute hides a class attribute with the same name when
accessed in this way.  Class attributes can be used as defaults for
instance attributes, but using mutable values there can lead to
unexpected results.  *note Descriptors: c70. can be used to create
instance variables with different implementation details.

See also
........

PEP 3115(3) - Metaclasses in Python 3000

     The proposal that changed the declaration of metaclasses to the
     current syntax, and the semantics for how classes with metaclasses
     are constructed.

PEP 3129(4) - Class Decorators

     The proposal that added class decorators.  Function and method
     decorators were introduced in PEP 318(5).

   ---------- Footnotes ----------

   (1) A string literal appearing as the first statement in the class
body is transformed into the namespace’s *note __doc__: 1e4d. item and
therefore the class’s *note docstring: 22e0.

   (2) https://peps.python.org/pep-0614/

   (3) https://peps.python.org/pep-3115/

   (4) https://peps.python.org/pep-3129/

   (5) https://peps.python.org/pep-0318/


File: python.info,  Node: Coroutines<2>,  Next: Type parameter lists,  Prev: Class definitions,  Up: Compound statements

4.8.9 Coroutines
----------------

Added in version 3.5.

* Menu:

* Coroutine function definition::
* The async for statement::
* The async with statement::


File: python.info,  Node: Coroutine function definition,  Next: The async for statement,  Up: Coroutines<2>

4.8.9.1 Coroutine function definition
.....................................

     async_funcdef ::= [*note decorators: 22d7.] "async" "def" *note funcname: 22d8. "(" [*note parameter_list: 223c.] ")"
                       ["->" *note expression: 21eb.] ":" *note suite: 2289.

Execution of Python coroutines can be suspended and resumed at many
points (see *note coroutine: 494.).  *note await: 1b9. expressions,
*note async for: ac0. and *note async with: 5d8. can only be used in the
body of a coroutine function.

Functions defined with ‘async def’ syntax are always coroutine
functions, even if they do not contain ‘await’ or ‘async’ keywords.

It is a *note SyntaxError: 18d. to use a ‘yield from’ expression inside
the body of a coroutine function.

An example of a coroutine function:

     async def func(param1, param2):
         do_stuff()
         await some_coroutine()

Changed in version 3.7: ‘await’ and ‘async’ are now keywords; previously
they were only treated as such inside the body of a coroutine function.


File: python.info,  Node: The async for statement,  Next: The async with statement,  Prev: Coroutine function definition,  Up: Coroutines<2>

4.8.9.2 The ‘async for’ statement
.................................

     async_for_stmt ::= "async" *note for_stmt: 2280.

An *note asynchronous iterable: da2. provides an ‘__aiter__’ method that
directly returns an *note asynchronous iterator: 1ab, which can call
asynchronous code in its ‘__anext__’ method.

The ‘async for’ statement allows convenient iteration over asynchronous
iterables.

The following code:

     async for TARGET in ITER:
         SUITE
     else:
         SUITE2

Is semantically equivalent to:

     iter = (ITER).__aiter__()
     running = True

     while running:
         try:
             TARGET = await iter.__anext__()
         except StopAsyncIteration:
             running = False
         else:
             SUITE
     else:
         SUITE2

except that implicit *note special method lookup: 2117. is used for
*note __aiter__(): c1c. and *note __anext__(): 1678.

It is a *note SyntaxError: 18d. to use an ‘async for’ statement outside
the body of a coroutine function.


File: python.info,  Node: The async with statement,  Prev: The async for statement,  Up: Coroutines<2>

4.8.9.3 The ‘async with’ statement
..................................

     async_with_stmt ::= "async" *note with_stmt: 2282.

An *note asynchronous context manager: 5da. is a *note context manager:
5d7. that is able to suspend execution in its 'enter' and 'exit'
methods.

The following code:

     async with EXPRESSION as TARGET:
         SUITE

is semantically equivalent to:

     manager = (EXPRESSION)
     aenter = manager.__aenter__
     aexit = manager.__aexit__
     value = await aenter()
     hit_except = False

     try:
         TARGET = value
         SUITE
     except:
         hit_except = True
         if not await aexit(*sys.exc_info()):
             raise
     finally:
         if not hit_except:
             await aexit(None, None, None)

except that implicit *note special method lookup: 2117. is used for
*note __aenter__(): 2181. and *note __aexit__(): 1734.

It is a *note SyntaxError: 18d. to use an ‘async with’ statement outside
the body of a coroutine function.

See also
........

PEP 492(1) - Coroutines with async and await syntax

     The proposal that made coroutines a proper standalone concept in
     Python, and added supporting syntax.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/


File: python.info,  Node: Type parameter lists,  Prev: Coroutines<2>,  Up: Compound statements

4.8.10 Type parameter lists
---------------------------

Added in version 3.12.

Changed in version 3.13: Support for default values was added (see PEP
696(1)).

     type_params  ::= "[" *note type_param: 22e9. ("," *note type_param: 22e9.)* "]"
     type_param   ::= *note typevar: 22ea. | *note typevartuple: 22eb. | *note paramspec: 22ec.
     typevar      ::= *note identifier: 2042. (":" *note expression: 21eb.)? ("=" *note expression: 21eb.)?
     typevartuple ::= "*" *note identifier: 2042. ("=" *note expression: 21eb.)?
     paramspec    ::= "**" *note identifier: 2042. ("=" *note expression: 21eb.)?

*note Functions: 14a9. (including *note coroutines: 5d4.), *note
classes: 131f. and *note type aliases: 43b. may contain a type parameter
list:

     def max[T](args: list[T]) -> T:
         ...

     async def amax[T](args: list[T]) -> T:
         ...

     class Bag[T]:
         def __iter__(self) -> Iterator[T]:
             ...

         def add(self, arg: T) -> None:
             ...

     type ListOrSet[T] = list[T] | set[T]

Semantically, this indicates that the function, class, or type alias is
generic over a type variable.  This information is primarily used by
static type checkers, and at runtime, generic objects behave much like
their non-generic counterparts.

Type parameters are declared in square brackets (‘[]’) immediately after
the name of the function, class, or type alias.  The type parameters are
accessible within the scope of the generic object, but not elsewhere.
Thus, after a declaration ‘def func[T](): pass’, the name ‘T’ is not
available in the module scope.  Below, the semantics of generic objects
are described with more precision.  The scope of type parameters is
modeled with a special function (technically, an *note annotation scope:
188.) that wraps the creation of the generic object.

Generic functions, classes, and type aliases have a *note
__type_params__: 22ed. attribute listing their type parameters.

Type parameters come in three kinds:

   * *note typing.TypeVar: 15d, introduced by a plain name (e.g., ‘T’).
     Semantically, this represents a single type to a type checker.

   * *note typing.TypeVarTuple: 15f, introduced by a name prefixed with
     a single asterisk (e.g., ‘*Ts’).  Semantically, this stands for a
     tuple of any number of types.

   * *note typing.ParamSpec: 15e, introduced by a name prefixed with two
     asterisks (e.g., ‘**P’).  Semantically, this stands for the
     parameters of a callable.

*note typing.TypeVar: 15d. declarations can define 'bounds' and
'constraints' with a colon (‘:’) followed by an expression.  A single
expression after the colon indicates a bound (e.g.  ‘T: int’).
Semantically, this means that the ‘typing.TypeVar’ can only represent
types that are a subtype of this bound.  A parenthesized tuple of
expressions after the colon indicates a set of constraints (e.g.  ‘T:
(str, bytes)’).  Each member of the tuple should be a type (again, this
is not enforced at runtime).  Constrained type variables can only take
on one of the types in the list of constraints.

For ‘typing.TypeVar’s declared using the type parameter list syntax, the
bound and constraints are not evaluated when the generic object is
created, but only when the value is explicitly accessed through the
attributes ‘__bound__’ and ‘__constraints__’.  To accomplish this, the
bounds or constraints are evaluated in a separate *note annotation
scope: 188.

*note typing.TypeVarTuple: 15f.s and *note typing.ParamSpec: 15e.s
cannot have bounds or constraints.

All three flavors of type parameters can also have a 'default value',
which is used when the type parameter is not explicitly provided.  This
is added by appending a single equals sign (‘=’) followed by an
expression.  Like the bounds and constraints of type variables, the
default value is not evaluated when the object is created, but only when
the type parameter’s ‘__default__’ attribute is accessed.  To this end,
the default value is evaluated in a separate *note annotation scope:
188.  If no default value is specified for a type parameter, the
‘__default__’ attribute is set to the special sentinel object *note
typing.NoDefault: 262.

The following example indicates the full set of allowed type parameter
declarations:

     def overly_generic[
        SimpleTypeVar,
        TypeVarWithDefault = int,
        TypeVarWithBound: int,
        TypeVarWithConstraints: (str, bytes),
        *SimpleTypeVarTuple = (int, float),
        **SimpleParamSpec = (str, bytearray),
     ](
        a: SimpleTypeVar,
        b: TypeVarWithDefault,
        c: TypeVarWithBound,
        d: Callable[SimpleParamSpec, TypeVarWithConstraints],
        *e: SimpleTypeVarTuple,
     ): ...

* Menu:

* Generic functions::
* Generic classes::
* Generic type aliases::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0696/


File: python.info,  Node: Generic functions,  Next: Generic classes,  Up: Type parameter lists

4.8.10.1 Generic functions
..........................

Generic functions are declared as follows:

     def func[T](arg: T): ...

This syntax is equivalent to:

     annotation-def TYPE_PARAMS_OF_func():
         T = typing.TypeVar("T")
         def func(arg: T): ...
         func.__type_params__ = (T,)
         return func
     func = TYPE_PARAMS_OF_func()

Here ‘annotation-def’ indicates an *note annotation scope: 188, which is
not actually bound to any name at runtime.  (One other liberty is taken
in the translation: the syntax does not go through attribute access on
the *note typing: 104. module, but creates an instance of *note
typing.TypeVar: 15d. directly.)

The annotations of generic functions are evaluated within the annotation
scope used for declaring the type parameters, but the function’s
defaults and decorators are not.

The following example illustrates the scoping rules for these cases, as
well as for additional flavors of type parameters:

     @decorator
     def func[T: int, *Ts, **P](*args: *Ts, arg: Callable[P, T] = some_default):
         ...

Except for the *note lazy evaluation: 45a. of the *note TypeVar: 15d.
bound, this is equivalent to:

     DEFAULT_OF_arg = some_default

     annotation-def TYPE_PARAMS_OF_func():

         annotation-def BOUND_OF_T():
             return int
         # In reality, BOUND_OF_T() is evaluated only on demand.
         T = typing.TypeVar("T", bound=BOUND_OF_T())

         Ts = typing.TypeVarTuple("Ts")
         P = typing.ParamSpec("P")

         def func(*args: *Ts, arg: Callable[P, T] = DEFAULT_OF_arg):
             ...

         func.__type_params__ = (T, Ts, P)
         return func
     func = decorator(TYPE_PARAMS_OF_func())

The capitalized names like ‘DEFAULT_OF_arg’ are not actually bound at
runtime.


File: python.info,  Node: Generic classes,  Next: Generic type aliases,  Prev: Generic functions,  Up: Type parameter lists

4.8.10.2 Generic classes
........................

Generic classes are declared as follows:

     class Bag[T]: ...

This syntax is equivalent to:

     annotation-def TYPE_PARAMS_OF_Bag():
         T = typing.TypeVar("T")
         class Bag(typing.Generic[T]):
             __type_params__ = (T,)
             ...
         return Bag
     Bag = TYPE_PARAMS_OF_Bag()

Here again ‘annotation-def’ (not a real keyword) indicates an *note
annotation scope: 188, and the name ‘TYPE_PARAMS_OF_Bag’ is not actually
bound at runtime.

Generic classes implicitly inherit from *note typing.Generic: 15fb.  The
base classes and keyword arguments of generic classes are evaluated
within the type scope for the type parameters, and decorators are
evaluated outside that scope.  This is illustrated by this example:

     @decorator
     class Bag(Base[T], arg=T): ...

This is equivalent to:

     annotation-def TYPE_PARAMS_OF_Bag():
         T = typing.TypeVar("T")
         class Bag(Base[T], typing.Generic[T], arg=T):
             __type_params__ = (T,)
             ...
         return Bag
     Bag = decorator(TYPE_PARAMS_OF_Bag())


File: python.info,  Node: Generic type aliases,  Prev: Generic classes,  Up: Type parameter lists

4.8.10.3 Generic type aliases
.............................

The *note type: 43b. statement can also be used to create a generic type
alias:

     type ListOrSet[T] = list[T] | set[T]

Except for the *note lazy evaluation: 45a. of the value, this is
equivalent to:

     annotation-def TYPE_PARAMS_OF_ListOrSet():
         T = typing.TypeVar("T")

         annotation-def VALUE_OF_ListOrSet():
             return list[T] | set[T]
         # In reality, the value is lazily evaluated
         return typing.TypeAliasType("ListOrSet", VALUE_OF_ListOrSet(), type_params=(T,))
     ListOrSet = TYPE_PARAMS_OF_ListOrSet()

Here, ‘annotation-def’ (not a real keyword) indicates an *note
annotation scope: 188.  The capitalized names like
‘TYPE_PARAMS_OF_ListOrSet’ are not actually bound at runtime.


File: python.info,  Node: Top-level components,  Next: Full Grammar specification,  Prev: Compound statements,  Up: The Python Language Reference

4.9 Top-level components
========================

The Python interpreter can get its input from a number of sources: from
a script passed to it as standard input or as program argument, typed in
interactively, from a module source file, etc.  This chapter gives the
syntax used in these cases.

* Menu:

* Complete Python programs::
* File input::
* Interactive input::
* Expression input::


File: python.info,  Node: Complete Python programs,  Next: File input,  Up: Top-level components

4.9.1 Complete Python programs
------------------------------

While a language specification need not prescribe how the language
interpreter is invoked, it is useful to have a notion of a complete
Python program.  A complete Python program is executed in a minimally
initialized environment: all built-in and standard modules are
available, but none have been initialized, except for *note sys: d9.
(various system services), *note builtins: 12. (built-in functions,
exceptions and ‘None’) and *note __main__: 1.  The latter is used to
provide the local and global namespace for execution of the complete
program.

The syntax for a complete Python program is that for file input,
described in the next section.

The interpreter may also be invoked in interactive mode; in this case,
it does not read and execute a complete program but reads and executes
one statement (possibly compound) at a time.  The initial environment is
identical to that of a complete program; each statement is executed in
the namespace of *note __main__: 1.

A complete program can be passed to the interpreter in three forms: with
the *note -c: 5e3. 'string' command line option, as a file passed as the
first command line argument, or as standard input.  If the file or
standard input is a tty device, the interpreter enters interactive mode;
otherwise, it executes the file as a complete program.


File: python.info,  Node: File input,  Next: Interactive input,  Prev: Complete Python programs,  Up: Top-level components

4.9.2 File input
----------------

All input read from non-interactive files has the same form:

     file_input ::= (NEWLINE | *note statement: 228b.)*

This syntax is used in the following situations:

   * when parsing a complete Python program (from a file or from a
     string);

   * when parsing a module;

   * when parsing a string passed to the *note exec(): 17f. function;


File: python.info,  Node: Interactive input,  Next: Expression input,  Prev: File input,  Up: Top-level components

4.9.3 Interactive input
-----------------------

Input in interactive mode is parsed using the following grammar:

     interactive_input ::= [*note stmt_list: 228a.] NEWLINE | *note compound_stmt: 227d. NEWLINE

Note that a (top-level) compound statement must be followed by a blank
line in interactive mode; this is needed to help the parser detect the
end of the input.


File: python.info,  Node: Expression input,  Prev: Interactive input,  Up: Top-level components

4.9.4 Expression input
----------------------

*note eval(): 180. is used for expression input.  It ignores leading
whitespace.  The string argument to ‘eval()’ must have the following
form:

     eval_input ::= *note expression_list: 2240. NEWLINE*


File: python.info,  Node: Full Grammar specification,  Prev: Top-level components,  Up: The Python Language Reference

4.10 Full Grammar specification
===============================

This is the full Python grammar, derived directly from the grammar used
to generate the CPython parser (see Grammar/python.gram(1)).  The
version here omits details related to code generation and error
recovery.

The notation is a mixture of EBNF(2) and PEG(3). In particular, ‘&’
followed by a symbol, token or parenthesized group indicates a positive
lookahead (i.e., is required to match but not consumed), while ‘!’
indicates a negative lookahead (i.e., is required 'not' to match).  We
use the ‘|’ separator to mean PEG’s “ordered choice” (written as ‘/’ in
traditional PEG grammars).  See PEP 617(4) for more details on the
grammar’s syntax.

     # PEG grammar for Python

     @trailer '''
     void *
     _PyPegen_parse(Parser *p)
     {
         // Initialize keywords
         p->keywords = reserved_keywords;
         p->n_keyword_lists = n_keyword_lists;
         p->soft_keywords = soft_keywords;

         // Run parser
         void *result = NULL;
         if (p->start_rule == Py_file_input) {
             result = file_rule(p);
         } else if (p->start_rule == Py_single_input) {
             result = interactive_rule(p);
         } else if (p->start_rule == Py_eval_input) {
             result = eval_rule(p);
         } else if (p->start_rule == Py_func_type_input) {
             result = func_type_rule(p);
         }

         return result;
     }
     '''

     # ========================= START OF THE GRAMMAR =========================

     # General grammatical elements and rules:
     #
     # * Strings with double quotes (") denote SOFT KEYWORDS
     # * Strings with single quotes (') denote KEYWORDS
     # * Upper case names (NAME) denote tokens in the Grammar/Tokens file
     # * Rule names starting with "invalid_" are used for specialized syntax errors
     #     - These rules are NOT used in the first pass of the parser.
     #     - Only if the first pass fails to parse, a second pass including the invalid
     #       rules will be executed.
     #     - If the parser fails in the second phase with a generic syntax error, the
     #       location of the generic failure of the first pass will be used (this avoids
     #       reporting incorrect locations due to the invalid rules).
     #     - The order of the alternatives involving invalid rules matter
     #       (like any rule in PEG).
     #
     # Grammar Syntax (see PEP 617 for more information):
     #
     # rule_name: expression
     #   Optionally, a type can be included right after the rule name, which
     #   specifies the return type of the C or Python function corresponding to the
     #   rule:
     # rule_name[return_type]: expression
     #   If the return type is omitted, then a void * is returned in C and an Any in
     #   Python.
     # e1 e2
     #   Match e1, then match e2.
     # e1 | e2
     #   Match e1 or e2.
     #   The first alternative can also appear on the line after the rule name for
     #   formatting purposes. In that case, a | must be used before the first
     #   alternative, like so:
     #       rule_name[return_type]:
     #            | first_alt
     #            | second_alt
     # ( e )
     #   Match e (allows also to use other operators in the group like '(e)*')
     # [ e ] or e?
     #   Optionally match e.
     # e*
     #   Match zero or more occurrences of e.
     # e+
     #   Match one or more occurrences of e.
     # s.e+
     #   Match one or more occurrences of e, separated by s. The generated parse tree
     #   does not include the separator. This is otherwise identical to (e (s e)*).
     # &e
     #   Succeed if e can be parsed, without consuming any input.
     # !e
     #   Fail if e can be parsed, without consuming any input.
     # ~
     #   Commit to the current alternative, even if it fails to parse.
     # &&e
     #   Eager parse e. The parser will not backtrack and will immediately
     #   fail with SyntaxError if e cannot be parsed.
     #

     # STARTING RULES
     # ==============

     file[mod_ty]: a=[statements] ENDMARKER { _PyPegen_make_module(p, a) }
     interactive[mod_ty]: a=statement_newline { _PyAST_Interactive(a, p->arena) }
     eval[mod_ty]: a=expressions NEWLINE* ENDMARKER { _PyAST_Expression(a, p->arena) }
     func_type[mod_ty]: '(' a=[type_expressions] ')' '->' b=expression NEWLINE* ENDMARKER { _PyAST_FunctionType(a, b, p->arena) }

     # GENERAL STATEMENTS
     # ==================

     statements[asdl_stmt_seq*]: a=statement+ { (asdl_stmt_seq*)_PyPegen_seq_flatten(p, a) }

     statement[asdl_stmt_seq*]: a=compound_stmt { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) } | a[asdl_stmt_seq*]=simple_stmts { a }

     statement_newline[asdl_stmt_seq*]:
         | a=compound_stmt NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) }
         | simple_stmts
         | NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, CHECK(stmt_ty, _PyAST_Pass(EXTRA))) }
         | ENDMARKER { _PyPegen_interactive_exit(p) }

     simple_stmts[asdl_stmt_seq*]:
         | a=simple_stmt !';' NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) } # Not needed, there for speedup
         | a[asdl_stmt_seq*]=';'.simple_stmt+ [';'] NEWLINE { a }

     # NOTE: assignment MUST precede expression, else parsing a simple assignment
     # will throw a SyntaxError.
     simple_stmt[stmt_ty] (memo):
         | assignment
         | &"type" type_alias
         | e=star_expressions { _PyAST_Expr(e, EXTRA) }
         | &'return' return_stmt
         | &('import' | 'from') import_stmt
         | &'raise' raise_stmt
         | 'pass' { _PyAST_Pass(EXTRA) }
         | &'del' del_stmt
         | &'yield' yield_stmt
         | &'assert' assert_stmt
         | 'break' { _PyAST_Break(EXTRA) }
         | 'continue' { _PyAST_Continue(EXTRA) }
         | &'global' global_stmt
         | &'nonlocal' nonlocal_stmt

     compound_stmt[stmt_ty]:
         | &('def' | '@' | 'async') function_def
         | &'if' if_stmt
         | &('class' | '@') class_def
         | &('with' | 'async') with_stmt
         | &('for' | 'async') for_stmt
         | &'try' try_stmt
         | &'while' while_stmt
         | match_stmt

     # SIMPLE STATEMENTS
     # =================

     # NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield'
     assignment[stmt_ty]:
         | a=NAME ':' b=expression c=['=' d=annotated_rhs { d }] {
             CHECK_VERSION(
                 stmt_ty,
                 6,
                 "Variable annotation syntax is",
                 _PyAST_AnnAssign(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), b, c, 1, EXTRA)
             ) }
         | a=('(' b=single_target ')' { b }
              | single_subscript_attribute_target) ':' b=expression c=['=' d=annotated_rhs { d }] {
             CHECK_VERSION(stmt_ty, 6, "Variable annotations syntax is", _PyAST_AnnAssign(a, b, c, 0, EXTRA)) }
         | a[asdl_expr_seq*]=(z=star_targets '=' { z })+ b=(yield_expr | star_expressions) !'=' tc=[TYPE_COMMENT] {
              _PyAST_Assign(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
         | a=single_target b=augassign ~ c=(yield_expr | star_expressions) {
              _PyAST_AugAssign(a, b->kind, c, EXTRA) }
         | invalid_assignment

     annotated_rhs[expr_ty]: yield_expr | star_expressions

     augassign[AugOperator*]:
         | '+=' { _PyPegen_augoperator(p, Add) }
         | '-=' { _PyPegen_augoperator(p, Sub) }
         | '*=' { _PyPegen_augoperator(p, Mult) }
         | '@=' { CHECK_VERSION(AugOperator*, 5, "The '@' operator is", _PyPegen_augoperator(p, MatMult)) }
         | '/=' { _PyPegen_augoperator(p, Div) }
         | '%=' { _PyPegen_augoperator(p, Mod) }
         | '&=' { _PyPegen_augoperator(p, BitAnd) }
         | '|=' { _PyPegen_augoperator(p, BitOr) }
         | '^=' { _PyPegen_augoperator(p, BitXor) }
         | '<<=' { _PyPegen_augoperator(p, LShift) }
         | '>>=' { _PyPegen_augoperator(p, RShift) }
         | '**=' { _PyPegen_augoperator(p, Pow) }
         | '//=' { _PyPegen_augoperator(p, FloorDiv) }

     return_stmt[stmt_ty]:
         | 'return' a=[star_expressions] { _PyAST_Return(a, EXTRA) }

     raise_stmt[stmt_ty]:
         | 'raise' a=expression b=['from' z=expression { z }] { _PyAST_Raise(a, b, EXTRA) }
         | 'raise' { _PyAST_Raise(NULL, NULL, EXTRA) }

     global_stmt[stmt_ty]: 'global' a[asdl_expr_seq*]=','.NAME+ {
         _PyAST_Global(CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, a)), EXTRA) }

     nonlocal_stmt[stmt_ty]: 'nonlocal' a[asdl_expr_seq*]=','.NAME+ {
         _PyAST_Nonlocal(CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, a)), EXTRA) }

     del_stmt[stmt_ty]:
         | 'del' a=del_targets &(';' | NEWLINE) { _PyAST_Delete(a, EXTRA) }
         | invalid_del_stmt

     yield_stmt[stmt_ty]: y=yield_expr { _PyAST_Expr(y, EXTRA) }

     assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _PyAST_Assert(a, b, EXTRA) }

     import_stmt[stmt_ty]:
         | invalid_import
         | import_name
         | import_from

     # Import statements
     # -----------------

     import_name[stmt_ty]: 'import' a=dotted_as_names { _PyAST_Import(a, EXTRA) }
     # note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
     import_from[stmt_ty]:
         | 'from' a=('.' | '...')* b=dotted_name 'import' c=import_from_targets {
             _PyPegen_checked_future_import(p, b->v.Name.id, c, _PyPegen_seq_count_dots(a), EXTRA) }
         | 'from' a=('.' | '...')+ 'import' b=import_from_targets {
             _PyAST_ImportFrom(NULL, b, _PyPegen_seq_count_dots(a), EXTRA) }
     import_from_targets[asdl_alias_seq*]:
         | '(' a=import_from_as_names [','] ')' { a }
         | import_from_as_names !','
         | '*' { (asdl_alias_seq*)_PyPegen_singleton_seq(p, CHECK(alias_ty, _PyPegen_alias_for_star(p, EXTRA))) }
         | invalid_import_from_targets
     import_from_as_names[asdl_alias_seq*]:
         | a[asdl_alias_seq*]=','.import_from_as_name+ { a }
     import_from_as_name[alias_ty]:
         | a=NAME b=['as' z=NAME { z }] { _PyAST_alias(a->v.Name.id,
                                                    (b) ? ((expr_ty) b)->v.Name.id : NULL,
                                                    EXTRA) }
     dotted_as_names[asdl_alias_seq*]:
         | a[asdl_alias_seq*]=','.dotted_as_name+ { a }
     dotted_as_name[alias_ty]:
         | a=dotted_name b=['as' z=NAME { z }] { _PyAST_alias(a->v.Name.id,
                                                           (b) ? ((expr_ty) b)->v.Name.id : NULL,
                                                           EXTRA) }
     dotted_name[expr_ty]:
         | a=dotted_name '.' b=NAME { _PyPegen_join_names_with_dot(p, a, b) }
         | NAME

     # COMPOUND STATEMENTS
     # ===================

     # Common elements
     # ---------------

     block[asdl_stmt_seq*] (memo):
         | NEWLINE INDENT a=statements DEDENT { a }
         | simple_stmts
         | invalid_block

     decorators[asdl_expr_seq*]: a[asdl_expr_seq*]=('@' f=named_expression NEWLINE { f })+ { a }

     # Class definitions
     # -----------------

     class_def[stmt_ty]:
         | a=decorators b=class_def_raw { _PyPegen_class_def_decorators(p, a, b) }
         | class_def_raw

     class_def_raw[stmt_ty]:
         | invalid_class_def_raw
         | 'class' a=NAME t=[type_params] b=['(' z=[arguments] ')' { z }] ':' c=block {
             _PyAST_ClassDef(a->v.Name.id,
                          (b) ? ((expr_ty) b)->v.Call.args : NULL,
                          (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
                          c, NULL, t, EXTRA) }

     # Function definitions
     # --------------------

     function_def[stmt_ty]:
         | d=decorators f=function_def_raw { _PyPegen_function_def_decorators(p, d, f) }
         | function_def_raw

     function_def_raw[stmt_ty]:
         | invalid_def_raw
         | 'def' n=NAME t=[type_params] '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
             _PyAST_FunctionDef(n->v.Name.id,
                             (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)),
                             b, NULL, a, NEW_TYPE_COMMENT(p, tc), t, EXTRA) }
         | 'async' 'def' n=NAME t=[type_params] '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
             CHECK_VERSION(
                 stmt_ty,
                 5,
                 "Async functions are",
                 _PyAST_AsyncFunctionDef(n->v.Name.id,
                                 (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)),
                                 b, NULL, a, NEW_TYPE_COMMENT(p, tc), t, EXTRA)
             ) }

     # Function parameters
     # -------------------

     params[arguments_ty]:
         | invalid_parameters
         | parameters

     parameters[arguments_ty]:
         | a=slash_no_default b[asdl_arg_seq*]=param_no_default* c=param_with_default* d=[star_etc] {
             CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, a, NULL, b, c, d)) }
         | a=slash_with_default b=param_with_default* c=[star_etc] {
             CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, NULL, a, NULL, b, c)) }
         | a[asdl_arg_seq*]=param_no_default+ b=param_with_default* c=[star_etc] {
             _PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
         | a=param_with_default+ b=[star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
         | a=star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }

     # Some duplication here because we can't write (',' | &')'),
     # which is because we don't support empty alternatives (yet).

     slash_no_default[asdl_arg_seq*]:
         | a[asdl_arg_seq*]=param_no_default+ '/' ',' { a }
         | a[asdl_arg_seq*]=param_no_default+ '/' &')' { a }
     slash_with_default[SlashWithDefault*]:
         | a=param_no_default* b=param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) }
         | a=param_no_default* b=param_with_default+ '/' &')' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) }

     star_etc[StarEtc*]:
         | invalid_star_etc
         | '*' a=param_no_default b=param_maybe_default* c=[kwds] {
             _PyPegen_star_etc(p, a, b, c) }
         | '*' a=param_no_default_star_annotation b=param_maybe_default* c=[kwds] {
             _PyPegen_star_etc(p, a, b, c) }
         | '*' ',' b=param_maybe_default+ c=[kwds] {
             _PyPegen_star_etc(p, NULL, b, c) }
         | a=kwds { _PyPegen_star_etc(p, NULL, NULL, a) }

     kwds[arg_ty]:
         | invalid_kwds
         | '**' a=param_no_default { a }

     # One parameter.  This *includes* a following comma and type comment.
     #
     # There are three styles:
     # - No default
     # - With default
     # - Maybe with default
     #
     # There are two alternative forms of each, to deal with type comments:
     # - Ends in a comma followed by an optional type comment
     # - No comma, optional type comment, must be followed by close paren
     # The latter form is for a final parameter without trailing comma.
     #

     param_no_default[arg_ty]:
         | a=param ',' tc=TYPE_COMMENT? { _PyPegen_add_type_comment_to_arg(p, a, tc) }
         | a=param tc=TYPE_COMMENT? &')' { _PyPegen_add_type_comment_to_arg(p, a, tc) }
     param_no_default_star_annotation[arg_ty]:
         | a=param_star_annotation ',' tc=TYPE_COMMENT? { _PyPegen_add_type_comment_to_arg(p, a, tc) }
         | a=param_star_annotation tc=TYPE_COMMENT? &')' { _PyPegen_add_type_comment_to_arg(p, a, tc) }
     param_with_default[NameDefaultPair*]:
         | a=param c=default ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) }
         | a=param c=default tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) }
     param_maybe_default[NameDefaultPair*]:
         | a=param c=default? ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) }
         | a=param c=default? tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) }
     param[arg_ty]: a=NAME b=annotation? { _PyAST_arg(a->v.Name.id, b, NULL, EXTRA) }
     param_star_annotation[arg_ty]: a=NAME b=star_annotation { _PyAST_arg(a->v.Name.id, b, NULL, EXTRA) }
     annotation[expr_ty]: ':' a=expression { a }
     star_annotation[expr_ty]: ':' a=star_expression { a }
     default[expr_ty]: '=' a=expression { a } | invalid_default

     # If statement
     # ------------

     if_stmt[stmt_ty]:
         | invalid_if_stmt
         | 'if' a=named_expression ':' b=block c=elif_stmt {
             _PyAST_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) }
         | 'if' a=named_expression ':' b=block c=[else_block] { _PyAST_If(a, b, c, EXTRA) }
     elif_stmt[stmt_ty]:
         | invalid_elif_stmt
         | 'elif' a=named_expression ':' b=block c=elif_stmt {
             _PyAST_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) }
         | 'elif' a=named_expression ':' b=block c=[else_block] { _PyAST_If(a, b, c, EXTRA) }
     else_block[asdl_stmt_seq*]:
         | invalid_else_stmt
         | 'else' &&':' b=block { b }

     # While statement
     # ---------------

     while_stmt[stmt_ty]:
         | invalid_while_stmt
         | 'while' a=named_expression ':' b=block c=[else_block] { _PyAST_While(a, b, c, EXTRA) }

     # For statement
     # -------------

     for_stmt[stmt_ty]:
         | invalid_for_stmt
         | 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
             _PyAST_For(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA) }
         | 'async' 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
             CHECK_VERSION(stmt_ty, 5, "Async for loops are", _PyAST_AsyncFor(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
         | invalid_for_target

     # With statement
     # --------------

     with_stmt[stmt_ty]:
         | invalid_with_stmt_indent
         | 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' tc=[TYPE_COMMENT] b=block {
            _PyAST_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
         | 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
             _PyAST_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
         | 'async' 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' b=block {
            CHECK_VERSION(stmt_ty, 5, "Async with statements are", _PyAST_AsyncWith(a, b, NULL, EXTRA)) }
         | 'async' 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
            CHECK_VERSION(stmt_ty, 5, "Async with statements are", _PyAST_AsyncWith(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
         | invalid_with_stmt

     with_item[withitem_ty]:
         | e=expression 'as' t=star_target &(',' | ')' | ':') { _PyAST_withitem(e, t, p->arena) }
         | invalid_with_item
         | e=expression { _PyAST_withitem(e, NULL, p->arena) }

     # Try statement
     # -------------

     try_stmt[stmt_ty]:
         | invalid_try_stmt
         | 'try' &&':' b=block f=finally_block { _PyAST_Try(b, NULL, NULL, f, EXTRA) }
         | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_block+ el=[else_block] f=[finally_block] { _PyAST_Try(b, ex, el, f, EXTRA) }
         | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_star_block+ el=[else_block] f=[finally_block] {
             CHECK_VERSION(stmt_ty, 11, "Exception groups are",
                           _PyAST_TryStar(b, ex, el, f, EXTRA)) }


     # Except statement
     # ----------------

     except_block[excepthandler_ty]:
         | invalid_except_stmt_indent
         | 'except' e=expression t=['as' z=NAME { z }] ':' b=block {
             _PyAST_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
         | 'except' ':' b=block { _PyAST_ExceptHandler(NULL, NULL, b, EXTRA) }
         | invalid_except_stmt
     except_star_block[excepthandler_ty]:
         | invalid_except_star_stmt_indent
         | 'except' '*' e=expression t=['as' z=NAME { z }] ':' b=block {
             _PyAST_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
         | invalid_except_stmt
     finally_block[asdl_stmt_seq*]:
         | invalid_finally_stmt
         | 'finally' &&':' a=block { a }

     # Match statement
     # ---------------

     match_stmt[stmt_ty]:
         | "match" subject=subject_expr ':' NEWLINE INDENT cases[asdl_match_case_seq*]=case_block+ DEDENT {
             CHECK_VERSION(stmt_ty, 10, "Pattern matching is", _PyAST_Match(subject, cases, EXTRA)) }
         | invalid_match_stmt

     subject_expr[expr_ty]:
         | value=star_named_expression ',' values=star_named_expressions? {
             _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, value, values)), Load, EXTRA) }
         | named_expression

     case_block[match_case_ty]:
         | invalid_case_block
         | "case" pattern=patterns guard=guard? ':' body=block {
             _PyAST_match_case(pattern, guard, body, p->arena) }

     guard[expr_ty]: 'if' guard=named_expression { guard }

     patterns[pattern_ty]:
         | patterns[asdl_pattern_seq*]=open_sequence_pattern {
             _PyAST_MatchSequence(patterns, EXTRA) }
         | pattern

     pattern[pattern_ty]:
         | as_pattern
         | or_pattern

     as_pattern[pattern_ty]:
         | pattern=or_pattern 'as' target=pattern_capture_target {
             _PyAST_MatchAs(pattern, target->v.Name.id, EXTRA) }
         | invalid_as_pattern

     or_pattern[pattern_ty]:
         | patterns[asdl_pattern_seq*]='|'.closed_pattern+ {
             asdl_seq_LEN(patterns) == 1 ? asdl_seq_GET(patterns, 0) : _PyAST_MatchOr(patterns, EXTRA) }

     closed_pattern[pattern_ty] (memo):
         | literal_pattern
         | capture_pattern
         | wildcard_pattern
         | value_pattern
         | group_pattern
         | sequence_pattern
         | mapping_pattern
         | class_pattern

     # Literal patterns are used for equality and identity constraints
     literal_pattern[pattern_ty]:
         | value=signed_number !('+' | '-') { _PyAST_MatchValue(value, EXTRA) }
         | value=complex_number { _PyAST_MatchValue(value, EXTRA) }
         | value=strings { _PyAST_MatchValue(value, EXTRA) }
         | 'None' { _PyAST_MatchSingleton(Py_None, EXTRA) }
         | 'True' { _PyAST_MatchSingleton(Py_True, EXTRA) }
         | 'False' { _PyAST_MatchSingleton(Py_False, EXTRA) }

     # Literal expressions are used to restrict permitted mapping pattern keys
     literal_expr[expr_ty]:
         | signed_number !('+' | '-')
         | complex_number
         | strings
         | 'None' { _PyAST_Constant(Py_None, NULL, EXTRA) }
         | 'True' { _PyAST_Constant(Py_True, NULL, EXTRA) }
         | 'False' { _PyAST_Constant(Py_False, NULL, EXTRA) }

     complex_number[expr_ty]:
         | real=signed_real_number '+' imag=imaginary_number {
             _PyAST_BinOp(real, Add, imag, EXTRA) }
         | real=signed_real_number '-' imag=imaginary_number  {
             _PyAST_BinOp(real, Sub, imag, EXTRA) }

     signed_number[expr_ty]:
         | NUMBER
         | '-' number=NUMBER { _PyAST_UnaryOp(USub, number, EXTRA) }

     signed_real_number[expr_ty]:
         | real_number
         | '-' real=real_number { _PyAST_UnaryOp(USub, real, EXTRA) }

     real_number[expr_ty]:
         | real=NUMBER { _PyPegen_ensure_real(p, real) }

     imaginary_number[expr_ty]:
         | imag=NUMBER { _PyPegen_ensure_imaginary(p, imag) }

     capture_pattern[pattern_ty]:
         | target=pattern_capture_target { _PyAST_MatchAs(NULL, target->v.Name.id, EXTRA) }

     pattern_capture_target[expr_ty]:
         | !"_" name=NAME !('.' | '(' | '=') {
             _PyPegen_set_expr_context(p, name, Store) }

     wildcard_pattern[pattern_ty]:
         | "_" { _PyAST_MatchAs(NULL, NULL, EXTRA) }

     value_pattern[pattern_ty]:
         | attr=attr !('.' | '(' | '=') { _PyAST_MatchValue(attr, EXTRA) }

     attr[expr_ty]:
         | value=name_or_attr '.' attr=NAME {
             _PyAST_Attribute(value, attr->v.Name.id, Load, EXTRA) }

     name_or_attr[expr_ty]:
         | attr
         | NAME

     group_pattern[pattern_ty]:
         | '(' pattern=pattern ')' { pattern }

     sequence_pattern[pattern_ty]:
         | '[' patterns=maybe_sequence_pattern? ']' { _PyAST_MatchSequence(patterns, EXTRA) }
         | '(' patterns=open_sequence_pattern? ')' { _PyAST_MatchSequence(patterns, EXTRA) }

     open_sequence_pattern[asdl_seq*]:
         | pattern=maybe_star_pattern ',' patterns=maybe_sequence_pattern? {
             _PyPegen_seq_insert_in_front(p, pattern, patterns) }

     maybe_sequence_pattern[asdl_seq*]:
         | patterns=','.maybe_star_pattern+ ','? { patterns }

     maybe_star_pattern[pattern_ty]:
         | star_pattern
         | pattern

     star_pattern[pattern_ty] (memo):
         | '*' target=pattern_capture_target {
             _PyAST_MatchStar(target->v.Name.id, EXTRA) }
         | '*' wildcard_pattern {
             _PyAST_MatchStar(NULL, EXTRA) }

     mapping_pattern[pattern_ty]:
         | '{' '}' {
             _PyAST_MatchMapping(NULL, NULL, NULL, EXTRA) }
         | '{' rest=double_star_pattern ','? '}' {
             _PyAST_MatchMapping(NULL, NULL, rest->v.Name.id, EXTRA) }
         | '{' items=items_pattern ',' rest=double_star_pattern ','? '}' {
             _PyAST_MatchMapping(
                 CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, items)),
                 CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, items)),
                 rest->v.Name.id,
                 EXTRA) }
         | '{' items=items_pattern ','? '}' {
             _PyAST_MatchMapping(
                 CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, items)),
                 CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, items)),
                 NULL,
                 EXTRA) }

     items_pattern[asdl_seq*]:
         | ','.key_value_pattern+

     key_value_pattern[KeyPatternPair*]:
         | key=(literal_expr | attr) ':' pattern=pattern {
             _PyPegen_key_pattern_pair(p, key, pattern) }

     double_star_pattern[expr_ty]:
         | '**' target=pattern_capture_target { target }

     class_pattern[pattern_ty]:
         | cls=name_or_attr '(' ')' {
             _PyAST_MatchClass(cls, NULL, NULL, NULL, EXTRA) }
         | cls=name_or_attr '(' patterns=positional_patterns ','? ')' {
             _PyAST_MatchClass(cls, patterns, NULL, NULL, EXTRA) }
         | cls=name_or_attr '(' keywords=keyword_patterns ','? ')' {
             _PyAST_MatchClass(
                 cls, NULL,
                 CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p,
                     CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, keywords)))),
                 CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, keywords)),
                 EXTRA) }
         | cls=name_or_attr '(' patterns=positional_patterns ',' keywords=keyword_patterns ','? ')' {
             _PyAST_MatchClass(
                 cls,
                 patterns,
                 CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p,
                     CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, keywords)))),
                 CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, keywords)),
                 EXTRA) }
         | invalid_class_pattern

     positional_patterns[asdl_pattern_seq*]:
         | args[asdl_pattern_seq*]=','.pattern+ { args }

     keyword_patterns[asdl_seq*]:
         | ','.keyword_pattern+

     keyword_pattern[KeyPatternPair*]:
         | arg=NAME '=' value=pattern { _PyPegen_key_pattern_pair(p, arg, value) }

     # Type statement
     # ---------------

     type_alias[stmt_ty]:
         | "type" n=NAME t=[type_params] '=' b=expression {
             CHECK_VERSION(stmt_ty, 12, "Type statement is",
             _PyAST_TypeAlias(CHECK(expr_ty, _PyPegen_set_expr_context(p, n, Store)), t, b, EXTRA)) }

     # Type parameter declaration
     # --------------------------

     type_params[asdl_type_param_seq*]:
         | invalid_type_params
         | '[' t=type_param_seq ']' {
             CHECK_VERSION(asdl_type_param_seq *, 12, "Type parameter lists are", t) }

     type_param_seq[asdl_type_param_seq*]: a[asdl_type_param_seq*]=','.type_param+ [','] { a }

     type_param[type_param_ty] (memo):
         | a=NAME b=[type_param_bound] c=[type_param_default] { _PyAST_TypeVar(a->v.Name.id, b, c, EXTRA) }
         | '*' a=NAME colon=':' e=expression {
                 RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind
                     ? "cannot use constraints with TypeVarTuple"
                     : "cannot use bound with TypeVarTuple")
             }
         | '*' a=NAME b=[type_param_starred_default] { _PyAST_TypeVarTuple(a->v.Name.id, b, EXTRA) }
         | '**' a=NAME colon=':' e=expression {
                 RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind
                     ? "cannot use constraints with ParamSpec"
                     : "cannot use bound with ParamSpec")
             }
         | '**' a=NAME b=[type_param_default] { _PyAST_ParamSpec(a->v.Name.id, b, EXTRA) }

     type_param_bound[expr_ty]: ':' e=expression { e }
     type_param_default[expr_ty]: '=' e=expression {
         CHECK_VERSION(expr_ty, 13, "Type parameter defaults are", e) }
     type_param_starred_default[expr_ty]: '=' e=star_expression {
         CHECK_VERSION(expr_ty, 13, "Type parameter defaults are", e) }

     # EXPRESSIONS
     # -----------

     expressions[expr_ty]:
         | a=expression b=(',' c=expression { c })+ [','] {
             _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
         | a=expression ',' { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_singleton_seq(p, a)), Load, EXTRA) }
         | expression

     expression[expr_ty] (memo):
         | invalid_expression
         | invalid_legacy_expression
         | a=disjunction 'if' b=disjunction 'else' c=expression { _PyAST_IfExp(b, a, c, EXTRA) }
         | disjunction
         | lambdef

     yield_expr[expr_ty]:
         | 'yield' 'from' a=expression { _PyAST_YieldFrom(a, EXTRA) }
         | 'yield' a=[star_expressions] { _PyAST_Yield(a, EXTRA) }

     star_expressions[expr_ty]:
         | a=star_expression b=(',' c=star_expression { c })+ [','] {
             _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
         | a=star_expression ',' { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_singleton_seq(p, a)), Load, EXTRA) }
         | star_expression

     star_expression[expr_ty] (memo):
         | '*' a=bitwise_or { _PyAST_Starred(a, Load, EXTRA) }
         | expression

     star_named_expressions[asdl_expr_seq*]: a[asdl_expr_seq*]=','.star_named_expression+ [','] { a }

     star_named_expression[expr_ty]:
         | '*' a=bitwise_or { _PyAST_Starred(a, Load, EXTRA) }
         | named_expression

     assignment_expression[expr_ty]:
         | a=NAME ':=' ~ b=expression {
             CHECK_VERSION(expr_ty, 8, "Assignment expressions are",
             _PyAST_NamedExpr(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), b, EXTRA)) }

     named_expression[expr_ty]:
         | assignment_expression
         | invalid_named_expression
         | expression !':='

     disjunction[expr_ty] (memo):
         | a=conjunction b=('or' c=conjunction { c })+ { _PyAST_BoolOp(
             Or,
             CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)),
             EXTRA) }
         | conjunction

     conjunction[expr_ty] (memo):
         | a=inversion b=('and' c=inversion { c })+ { _PyAST_BoolOp(
             And,
             CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)),
             EXTRA) }
         | inversion

     inversion[expr_ty] (memo):
         | 'not' a=inversion { _PyAST_UnaryOp(Not, a, EXTRA) }
         | comparison

     # Comparison operators
     # --------------------

     comparison[expr_ty]:
         | a=bitwise_or b=compare_op_bitwise_or_pair+ {
             _PyAST_Compare(
                 a,
                 CHECK(asdl_int_seq*, _PyPegen_get_cmpops(p, b)),
                 CHECK(asdl_expr_seq*, _PyPegen_get_exprs(p, b)),
                 EXTRA) }
         | bitwise_or

     compare_op_bitwise_or_pair[CmpopExprPair*]:
         | eq_bitwise_or
         | noteq_bitwise_or
         | lte_bitwise_or
         | lt_bitwise_or
         | gte_bitwise_or
         | gt_bitwise_or
         | notin_bitwise_or
         | in_bitwise_or
         | isnot_bitwise_or
         | is_bitwise_or

     eq_bitwise_or[CmpopExprPair*]: '==' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Eq, a) }
     noteq_bitwise_or[CmpopExprPair*]:
         | (tok='!=' { _PyPegen_check_barry_as_flufl(p, tok) ? NULL : tok}) a=bitwise_or {_PyPegen_cmpop_expr_pair(p, NotEq, a) }
     lte_bitwise_or[CmpopExprPair*]: '<=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, LtE, a) }
     lt_bitwise_or[CmpopExprPair*]: '<' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Lt, a) }
     gte_bitwise_or[CmpopExprPair*]: '>=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, GtE, a) }
     gt_bitwise_or[CmpopExprPair*]: '>' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Gt, a) }
     notin_bitwise_or[CmpopExprPair*]: 'not' 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, NotIn, a) }
     in_bitwise_or[CmpopExprPair*]: 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, In, a) }
     isnot_bitwise_or[CmpopExprPair*]: 'is' 'not' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, IsNot, a) }
     is_bitwise_or[CmpopExprPair*]: 'is' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Is, a) }

     # Bitwise operators
     # -----------------

     bitwise_or[expr_ty]:
         | a=bitwise_or '|' b=bitwise_xor { _PyAST_BinOp(a, BitOr, b, EXTRA) }
         | bitwise_xor

     bitwise_xor[expr_ty]:
         | a=bitwise_xor '^' b=bitwise_and { _PyAST_BinOp(a, BitXor, b, EXTRA) }
         | bitwise_and

     bitwise_and[expr_ty]:
         | a=bitwise_and '&' b=shift_expr { _PyAST_BinOp(a, BitAnd, b, EXTRA) }
         | shift_expr

     shift_expr[expr_ty]:
         | a=shift_expr '<<' b=sum { _PyAST_BinOp(a, LShift, b, EXTRA) }
         | a=shift_expr '>>' b=sum { _PyAST_BinOp(a, RShift, b, EXTRA) }
         | invalid_arithmetic
         | sum

     # Arithmetic operators
     # --------------------

     sum[expr_ty]:
         | a=sum '+' b=term { _PyAST_BinOp(a, Add, b, EXTRA) }
         | a=sum '-' b=term { _PyAST_BinOp(a, Sub, b, EXTRA) }
         | term

     term[expr_ty]:
         | a=term '*' b=factor { _PyAST_BinOp(a, Mult, b, EXTRA) }
         | a=term '/' b=factor { _PyAST_BinOp(a, Div, b, EXTRA) }
         | a=term '//' b=factor { _PyAST_BinOp(a, FloorDiv, b, EXTRA) }
         | a=term '%' b=factor { _PyAST_BinOp(a, Mod, b, EXTRA) }
         | a=term '@' b=factor { CHECK_VERSION(expr_ty, 5, "The '@' operator is", _PyAST_BinOp(a, MatMult, b, EXTRA)) }
         | invalid_factor
         | factor

     factor[expr_ty] (memo):
         | '+' a=factor { _PyAST_UnaryOp(UAdd, a, EXTRA) }
         | '-' a=factor { _PyAST_UnaryOp(USub, a, EXTRA) }
         | '~' a=factor { _PyAST_UnaryOp(Invert, a, EXTRA) }
         | power

     power[expr_ty]:
         | a=await_primary '**' b=factor { _PyAST_BinOp(a, Pow, b, EXTRA) }
         | await_primary

     # Primary elements
     # ----------------

     # Primary elements are things like "obj.something.something", "obj[something]", "obj(something)", "obj" ...

     await_primary[expr_ty] (memo):
         | 'await' a=primary { CHECK_VERSION(expr_ty, 5, "Await expressions are", _PyAST_Await(a, EXTRA)) }
         | primary

     primary[expr_ty]:
         | a=primary '.' b=NAME { _PyAST_Attribute(a, b->v.Name.id, Load, EXTRA) }
         | a=primary b=genexp { _PyAST_Call(a, CHECK(asdl_expr_seq*, (asdl_expr_seq*)_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
         | a=primary '(' b=[arguments] ')' {
             _PyAST_Call(a,
                      (b) ? ((expr_ty) b)->v.Call.args : NULL,
                      (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
                      EXTRA) }
         | a=primary '[' b=slices ']' { _PyAST_Subscript(a, b, Load, EXTRA) }
         | atom

     slices[expr_ty]:
         | a=slice !',' { a }
         | a[asdl_expr_seq*]=','.(slice | starred_expression)+ [','] { _PyAST_Tuple(a, Load, EXTRA) }

     slice[expr_ty]:
         | a=[expression] ':' b=[expression] c=[':' d=[expression] { d }] { _PyAST_Slice(a, b, c, EXTRA) }
         | a=named_expression { a }

     atom[expr_ty]:
         | NAME
         | 'True' { _PyAST_Constant(Py_True, NULL, EXTRA) }
         | 'False' { _PyAST_Constant(Py_False, NULL, EXTRA) }
         | 'None' { _PyAST_Constant(Py_None, NULL, EXTRA) }
         | &(STRING|FSTRING_START) strings
         | NUMBER
         | &'(' (tuple | group | genexp)
         | &'[' (list | listcomp)
         | &'{' (dict | set | dictcomp | setcomp)
         | '...' { _PyAST_Constant(Py_Ellipsis, NULL, EXTRA) }

     group[expr_ty]:
         | '(' a=(yield_expr | named_expression) ')' { a }
         | invalid_group

     # Lambda functions
     # ----------------

     lambdef[expr_ty]:
         | 'lambda' a=[lambda_params] ':' b=expression {
             _PyAST_Lambda((a) ? a : CHECK(arguments_ty, _PyPegen_empty_arguments(p)), b, EXTRA) }

     lambda_params[arguments_ty]:
         | invalid_lambda_parameters
         | lambda_parameters

     # lambda_parameters etc. duplicates parameters but without annotations
     # or type comments, and if there's no comma after a parameter, we expect
     # a colon, not a close parenthesis.  (For more, see parameters above.)
     #
     lambda_parameters[arguments_ty]:
         | a=lambda_slash_no_default b[asdl_arg_seq*]=lambda_param_no_default* c=lambda_param_with_default* d=[lambda_star_etc] {
             CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, a, NULL, b, c, d)) }
         | a=lambda_slash_with_default b=lambda_param_with_default* c=[lambda_star_etc] {
             CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, NULL, a, NULL, b, c)) }
         | a[asdl_arg_seq*]=lambda_param_no_default+ b=lambda_param_with_default* c=[lambda_star_etc] {
             _PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
         | a=lambda_param_with_default+ b=[lambda_star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
         | a=lambda_star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }

     lambda_slash_no_default[asdl_arg_seq*]:
         | a[asdl_arg_seq*]=lambda_param_no_default+ '/' ',' { a }
         | a[asdl_arg_seq*]=lambda_param_no_default+ '/' &':' { a }

     lambda_slash_with_default[SlashWithDefault*]:
         | a=lambda_param_no_default* b=lambda_param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) }
         | a=lambda_param_no_default* b=lambda_param_with_default+ '/' &':' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) }

     lambda_star_etc[StarEtc*]:
         | invalid_lambda_star_etc
         | '*' a=lambda_param_no_default b=lambda_param_maybe_default* c=[lambda_kwds] {
             _PyPegen_star_etc(p, a, b, c) }
         | '*' ',' b=lambda_param_maybe_default+ c=[lambda_kwds] {
             _PyPegen_star_etc(p, NULL, b, c) }
         | a=lambda_kwds { _PyPegen_star_etc(p, NULL, NULL, a) }

     lambda_kwds[arg_ty]:
         | invalid_lambda_kwds
         | '**' a=lambda_param_no_default { a }

     lambda_param_no_default[arg_ty]:
         | a=lambda_param ',' { a }
         | a=lambda_param &':' { a }
     lambda_param_with_default[NameDefaultPair*]:
         | a=lambda_param c=default ',' { _PyPegen_name_default_pair(p, a, c, NULL) }
         | a=lambda_param c=default &':' { _PyPegen_name_default_pair(p, a, c, NULL) }
     lambda_param_maybe_default[NameDefaultPair*]:
         | a=lambda_param c=default? ',' { _PyPegen_name_default_pair(p, a, c, NULL) }
         | a=lambda_param c=default? &':' { _PyPegen_name_default_pair(p, a, c, NULL) }
     lambda_param[arg_ty]: a=NAME { _PyAST_arg(a->v.Name.id, NULL, NULL, EXTRA) }

     # LITERALS
     # ========

     fstring_middle[expr_ty]:
         | fstring_replacement_field
         | t=FSTRING_MIDDLE { _PyPegen_constant_from_token(p, t) }
     fstring_replacement_field[expr_ty]:
         | '{' a=annotated_rhs debug_expr='='? conversion=[fstring_conversion] format=[fstring_full_format_spec] rbrace='}' {
             _PyPegen_formatted_value(p, a, debug_expr, conversion, format, rbrace, EXTRA) }
         | invalid_replacement_field
     fstring_conversion[ResultTokenWithMetadata*]:
         | conv_token="!" conv=NAME { _PyPegen_check_fstring_conversion(p, conv_token, conv) }
     fstring_full_format_spec[ResultTokenWithMetadata*]:
         | colon=':' spec=fstring_format_spec* { _PyPegen_setup_full_format_spec(p, colon, (asdl_expr_seq *) spec, EXTRA) }
     fstring_format_spec[expr_ty]:
         | t=FSTRING_MIDDLE { _PyPegen_decoded_constant_from_token(p, t) }
         | fstring_replacement_field
     fstring[expr_ty]:
         | a=FSTRING_START b=fstring_middle* c=FSTRING_END { _PyPegen_joined_str(p, a, (asdl_expr_seq*)b, c) }

     string[expr_ty]: s[Token*]=STRING { _PyPegen_constant_from_string(p, s) }
     strings[expr_ty] (memo): a[asdl_expr_seq*]=(fstring|string)+ { _PyPegen_concatenate_strings(p, a, EXTRA) }

     list[expr_ty]:
         | '[' a=[star_named_expressions] ']' { _PyAST_List(a, Load, EXTRA) }

     tuple[expr_ty]:
         | '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' {
             _PyAST_Tuple(a, Load, EXTRA) }

     set[expr_ty]: '{' a=star_named_expressions '}' { _PyAST_Set(a, EXTRA) }

     # Dicts
     # -----

     dict[expr_ty]:
         | '{' a=[double_starred_kvpairs] '}' {
             _PyAST_Dict(
                 CHECK(asdl_expr_seq*, _PyPegen_get_keys(p, a)),
                 CHECK(asdl_expr_seq*, _PyPegen_get_values(p, a)),
                 EXTRA) }
         | '{' invalid_double_starred_kvpairs '}'

     double_starred_kvpairs[asdl_seq*]: a=','.double_starred_kvpair+ [','] { a }

     double_starred_kvpair[KeyValuePair*]:
         | '**' a=bitwise_or { _PyPegen_key_value_pair(p, NULL, a) }
         | kvpair

     kvpair[KeyValuePair*]: a=expression ':' b=expression { _PyPegen_key_value_pair(p, a, b) }

     # Comprehensions & Generators
     # ---------------------------

     for_if_clauses[asdl_comprehension_seq*]:
         | a[asdl_comprehension_seq*]=for_if_clause+ { a }

     for_if_clause[comprehension_ty]:
         | 'async' 'for' a=star_targets 'in' ~ b=disjunction c[asdl_expr_seq*]=('if' z=disjunction { z })* {
             CHECK_VERSION(comprehension_ty, 6, "Async comprehensions are", _PyAST_comprehension(a, b, c, 1, p->arena)) }
         | 'for' a=star_targets 'in' ~ b=disjunction c[asdl_expr_seq*]=('if' z=disjunction { z })* {
             _PyAST_comprehension(a, b, c, 0, p->arena) }
         | 'async'? 'for' (bitwise_or (',' bitwise_or)* [',']) !'in' {
             RAISE_SYNTAX_ERROR("'in' expected after for-loop variables") }
         | invalid_for_target

     listcomp[expr_ty]:
         | '[' a=named_expression b=for_if_clauses ']' { _PyAST_ListComp(a, b, EXTRA) }
         | invalid_comprehension

     setcomp[expr_ty]:
         | '{' a=named_expression b=for_if_clauses '}' { _PyAST_SetComp(a, b, EXTRA) }
         | invalid_comprehension

     genexp[expr_ty]:
         | '(' a=( assignment_expression | expression !':=') b=for_if_clauses ')' { _PyAST_GeneratorExp(a, b, EXTRA) }
         | invalid_comprehension

     dictcomp[expr_ty]:
         | '{' a=kvpair b=for_if_clauses '}' { _PyAST_DictComp(a->key, a->value, b, EXTRA) }
         | invalid_dict_comprehension

     # FUNCTION CALL ARGUMENTS
     # =======================

     arguments[expr_ty] (memo):
         | a=args [','] &')' { a }
         | invalid_arguments

     args[expr_ty]:
         | a[asdl_expr_seq*]=','.(starred_expression | ( assignment_expression | expression !':=') !'=')+ b=[',' k=kwargs {k}] {
             _PyPegen_collect_call_seqs(p, a, b, EXTRA) }
         | a=kwargs { _PyAST_Call(_PyPegen_dummy_name(p),
                               CHECK_NULL_ALLOWED(asdl_expr_seq*, _PyPegen_seq_extract_starred_exprs(p, a)),
                               CHECK_NULL_ALLOWED(asdl_keyword_seq*, _PyPegen_seq_delete_starred_exprs(p, a)),
                               EXTRA) }

     kwargs[asdl_seq*]:
         | a=','.kwarg_or_starred+ ',' b=','.kwarg_or_double_starred+ { _PyPegen_join_sequences(p, a, b) }
         | ','.kwarg_or_starred+
         | ','.kwarg_or_double_starred+

     starred_expression[expr_ty]:
         | invalid_starred_expression
         | '*' a=expression { _PyAST_Starred(a, Load, EXTRA) }
         | '*' { RAISE_SYNTAX_ERROR("Invalid star expression") }

     kwarg_or_starred[KeywordOrStarred*]:
         | invalid_kwarg
         | a=NAME '=' b=expression {
             _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) }
         | a=starred_expression { _PyPegen_keyword_or_starred(p, a, 0) }

     kwarg_or_double_starred[KeywordOrStarred*]:
         | invalid_kwarg
         | a=NAME '=' b=expression {
             _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) }
         | '**' a=expression { _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(NULL, a, EXTRA)), 1) }

     # ASSIGNMENT TARGETS
     # ==================

     # Generic targets
     # ---------------

     # NOTE: star_targets may contain *bitwise_or, targets may not.
     star_targets[expr_ty]:
         | a=star_target !',' { a }
         | a=star_target b=(',' c=star_target { c })* [','] {
             _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Store, EXTRA) }

     star_targets_list_seq[asdl_expr_seq*]: a[asdl_expr_seq*]=','.star_target+ [','] { a }

     star_targets_tuple_seq[asdl_expr_seq*]:
         | a=star_target b=(',' c=star_target { c })+ [','] { (asdl_expr_seq*) _PyPegen_seq_insert_in_front(p, a, b) }
         | a=star_target ',' { (asdl_expr_seq*) _PyPegen_singleton_seq(p, a) }

     star_target[expr_ty] (memo):
         | '*' a=(!'*' star_target) {
             _PyAST_Starred(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), Store, EXTRA) }
         | target_with_star_atom

     target_with_star_atom[expr_ty] (memo):
         | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Store, EXTRA) }
         | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_Subscript(a, b, Store, EXTRA) }
         | star_atom

     star_atom[expr_ty]:
         | a=NAME { _PyPegen_set_expr_context(p, a, Store) }
         | '(' a=target_with_star_atom ')' { _PyPegen_set_expr_context(p, a, Store) }
         | '(' a=[star_targets_tuple_seq] ')' { _PyAST_Tuple(a, Store, EXTRA) }
         | '[' a=[star_targets_list_seq] ']' { _PyAST_List(a, Store, EXTRA) }

     single_target[expr_ty]:
         | single_subscript_attribute_target
         | a=NAME { _PyPegen_set_expr_context(p, a, Store) }
         | '(' a=single_target ')' { a }

     single_subscript_attribute_target[expr_ty]:
         | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Store, EXTRA) }
         | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_Subscript(a, b, Store, EXTRA) }

     t_primary[expr_ty]:
         | a=t_primary '.' b=NAME &t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Load, EXTRA) }
         | a=t_primary '[' b=slices ']' &t_lookahead { _PyAST_Subscript(a, b, Load, EXTRA) }
         | a=t_primary b=genexp &t_lookahead {
             _PyAST_Call(a, CHECK(asdl_expr_seq*, (asdl_expr_seq*)_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
         | a=t_primary '(' b=[arguments] ')' &t_lookahead {
             _PyAST_Call(a,
                      (b) ? ((expr_ty) b)->v.Call.args : NULL,
                      (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
                      EXTRA) }
         | a=atom &t_lookahead { a }

     t_lookahead: '(' | '[' | '.'

     # Targets for del statements
     # --------------------------

     del_targets[asdl_expr_seq*]: a[asdl_expr_seq*]=','.del_target+ [','] { a }

     del_target[expr_ty] (memo):
         | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Del, EXTRA) }
         | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_Subscript(a, b, Del, EXTRA) }
         | del_t_atom

     del_t_atom[expr_ty]:
         | a=NAME { _PyPegen_set_expr_context(p, a, Del) }
         | '(' a=del_target ')' { _PyPegen_set_expr_context(p, a, Del) }
         | '(' a=[del_targets] ')' { _PyAST_Tuple(a, Del, EXTRA) }
         | '[' a=[del_targets] ']' { _PyAST_List(a, Del, EXTRA) }

     # TYPING ELEMENTS
     # ---------------

     # type_expressions allow */** but ignore them
     type_expressions[asdl_expr_seq*]:
         | a=','.expression+ ',' '*' b=expression ',' '**' c=expression {
             (asdl_expr_seq*)_PyPegen_seq_append_to_end(
                 p,
                 CHECK(asdl_seq*, _PyPegen_seq_append_to_end(p, a, b)),
                 c) }
         | a=','.expression+ ',' '*' b=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end(p, a, b) }
         | a=','.expression+ ',' '**' b=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end(p, a, b) }
         | '*' a=expression ',' '**' b=expression {
             (asdl_expr_seq*)_PyPegen_seq_append_to_end(
                 p,
                 CHECK(asdl_seq*, _PyPegen_singleton_seq(p, a)),
                 b) }
         | '*' a=expression { (asdl_expr_seq*)_PyPegen_singleton_seq(p, a) }
         | '**' a=expression { (asdl_expr_seq*)_PyPegen_singleton_seq(p, a) }
         | a[asdl_expr_seq*]=','.expression+ {a}

     func_type_comment[Token*]:
         | NEWLINE t=TYPE_COMMENT &(NEWLINE INDENT) { t }  # Must be followed by indented block
         | invalid_double_type_comments
         | TYPE_COMMENT

     # ========================= END OF THE GRAMMAR ===========================



     # ========================= START OF INVALID RULES =======================

     # From here on, there are rules for invalid syntax with specialised error messages
     invalid_arguments:
         | ((','.(starred_expression | ( assignment_expression | expression !':=') !'=')+ ',' kwargs) | kwargs) a=',' ','.(starred_expression !'=')+ {
             RAISE_SYNTAX_ERROR_STARTING_FROM(a, "iterable argument unpacking follows keyword argument unpacking") }
         | a=expression b=for_if_clauses ',' [args | expression for_if_clauses] {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, _PyPegen_get_last_comprehension_item(PyPegen_last_item(b, comprehension_ty)), "Generator expression must be parenthesized") }
         | a=NAME b='=' expression for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?")}
         | (args ',')? a=NAME b='=' &(',' | ')') {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "expected argument value expression")}
         | a=args b=for_if_clauses { _PyPegen_nonparen_genexp_in_call(p, a, b) }
         | args ',' a=expression b=for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, _PyPegen_get_last_comprehension_item(PyPegen_last_item(b, comprehension_ty)), "Generator expression must be parenthesized") }
         | a=args ',' args { _PyPegen_arguments_parsing_error(p, a) }
     invalid_kwarg:
         | a[Token*]=('True'|'False'|'None') b='=' {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to %s", PyBytes_AS_STRING(a->bytes)) }
         | a=NAME b='=' expression for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?")}
         | !(NAME '=') a=expression b='=' {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(
                 a, b, "expression cannot contain assignment, perhaps you meant \"==\"?") }
         | a='**' expression '=' b=expression {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to keyword argument unpacking") }

     # IMPORTANT: Note that the "_without_invalid" suffix causes the rule to not call invalid rules under it
     expression_without_invalid[expr_ty]:
         | a=disjunction 'if' b=disjunction 'else' c=expression { _PyAST_IfExp(b, a, c, EXTRA) }
         | disjunction
         | lambdef
     invalid_legacy_expression:
         | a=NAME !'(' b=star_expressions {
             _PyPegen_check_legacy_stmt(p, a) ? RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b,
                 "Missing parentheses in call to '%U'. Did you mean %U(...)?", a->v.Name.id, a->v.Name.id) : NULL}

     invalid_expression:
         # !(NAME STRING) is not matched so we don't show this error with some invalid string prefixes like: kf"dsfsdf"
         # Soft keywords need to also be ignored because they can be parsed as NAME NAME
        | !(NAME STRING | SOFT_KEYWORD) a=disjunction b=expression_without_invalid {
             _PyPegen_check_legacy_stmt(p, a) ? NULL : p->tokens[p->mark-1]->level == 0 ? NULL :
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Perhaps you forgot a comma?") }
        | a=disjunction 'if' b=disjunction !('else'|':') { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "expected 'else' after 'if' expression") }
        | a='lambda' [lambda_params] b=':' &FSTRING_MIDDLE  {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "f-string: lambda expressions are not allowed without parentheses") }

     invalid_named_expression(memo):
         | a=expression ':=' expression {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
                 a, "cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) }
         | a=NAME '=' b=bitwise_or !('='|':=') {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?") }
         | !(list|tuple|genexp|'True'|'None'|'False') a=bitwise_or b='=' bitwise_or !('='|':=') {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot assign to %s here. Maybe you meant '==' instead of '='?",
                                               _PyPegen_get_expr_name(a)) }

     invalid_assignment:
         | a=invalid_ann_assign_target ':' expression {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
                 a,
                 "only single target (not %s) can be annotated",
                 _PyPegen_get_expr_name(a)
             )}
         | a=star_named_expression ',' star_named_expressions* ':' expression {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not tuple) can be annotated") }
         | a=expression ':' expression {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") }
         | (star_targets '=')* a=star_expressions '=' {
             RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
         | (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") }
         | a=star_expressions augassign annotated_rhs {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
                 a,
                 "'%s' is an illegal expression for augmented assignment",
                 _PyPegen_get_expr_name(a)
             )}
     invalid_ann_assign_target[expr_ty]:
         | list
         | tuple
         | '(' a=invalid_ann_assign_target ')' { a }
     invalid_del_stmt:
         | 'del' a=star_expressions {
             RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }
     invalid_block:
         | NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
     invalid_comprehension:
         | ('[' | '(' | '{') a=starred_expression for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "iterable unpacking cannot be used in comprehension") }
         | ('[' | '{') a=star_named_expression ',' b=star_named_expressions for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, PyPegen_last_item(b, expr_ty),
             "did you forget parentheses around the comprehension target?") }
         | ('[' | '{') a=star_named_expression b=',' for_if_clauses {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "did you forget parentheses around the comprehension target?") }
     invalid_dict_comprehension:
         | '{' a='**' bitwise_or for_if_clauses '}' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "dict unpacking cannot be used in dict comprehension") }
     invalid_parameters:
         | a="/" ',' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "at least one argument must precede /") }
         | (slash_no_default | slash_with_default) param_maybe_default* a='/' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ may appear only once") }
         | slash_no_default? param_no_default* invalid_parameters_helper a=param_no_default {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameter without a default follows parameter with a default") }
         | param_no_default* a='(' param_no_default+ ','? b=')' {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "Function parameters cannot be parenthesized") }
         | (slash_no_default | slash_with_default)? param_maybe_default* '*' (',' | param_no_default) param_maybe_default* a='/' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ must be ahead of *") }
         | param_maybe_default+ '/' a='*' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected comma between / and *") }
     invalid_default:
         | a='=' &(')'|',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected default value expression") }
     invalid_star_etc:
         | a='*' (')' | ',' (')' | '**')) { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "named arguments must follow bare *") }
         | '*' ',' TYPE_COMMENT { RAISE_SYNTAX_ERROR("bare * has associated type comment") }
         | '*' param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-positional argument cannot have default value") }
         | '*' (param_no_default | ',') param_maybe_default* a='*' (param_no_default | ',') {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "* argument may appear only once") }
     invalid_kwds:
         | '**' param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-keyword argument cannot have default value") }
         | '**' param ',' a=param { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") }
         | '**' param ',' a[Token*]=('*'|'**'|'/') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") }
     invalid_parameters_helper: # This is only there to avoid type errors
         | a=slash_with_default { _PyPegen_singleton_seq(p, a) }
         | param_with_default+
     invalid_lambda_parameters:
         | a="/" ',' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "at least one argument must precede /") }
         | (lambda_slash_no_default | lambda_slash_with_default) lambda_param_maybe_default* a='/' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ may appear only once") }
         | lambda_slash_no_default? lambda_param_no_default* invalid_lambda_parameters_helper a=lambda_param_no_default {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameter without a default follows parameter with a default") }
         | lambda_param_no_default* a='(' ','.lambda_param+ ','? b=')' {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "Lambda expression parameters cannot be parenthesized") }
         | (lambda_slash_no_default | lambda_slash_with_default)? lambda_param_maybe_default* '*' (',' | lambda_param_no_default) lambda_param_maybe_default* a='/' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ must be ahead of *") }
         | lambda_param_maybe_default+ '/' a='*' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected comma between / and *") }
     invalid_lambda_parameters_helper:
         | a=lambda_slash_with_default { _PyPegen_singleton_seq(p, a) }
         | lambda_param_with_default+
     invalid_lambda_star_etc:
         | '*' (':' | ',' (':' | '**')) { RAISE_SYNTAX_ERROR("named arguments must follow bare *") }
         | '*' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-positional argument cannot have default value") }
         | '*' (lambda_param_no_default | ',') lambda_param_maybe_default* a='*' (lambda_param_no_default | ',') {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "* argument may appear only once") }
     invalid_lambda_kwds:
         | '**' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-keyword argument cannot have default value") }
         | '**' lambda_param ',' a=lambda_param { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") }
         | '**' lambda_param ',' a[Token*]=('*'|'**'|'/') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") }
     invalid_double_type_comments:
         | TYPE_COMMENT NEWLINE TYPE_COMMENT NEWLINE INDENT {
             RAISE_SYNTAX_ERROR("Cannot have two type comments on def") }
     invalid_with_item:
         | expression 'as' a=expression &(',' | ')' | ':') {
             RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }

     invalid_for_target:
         | 'async'? 'for' a=star_expressions {
             RAISE_SYNTAX_ERROR_INVALID_TARGET(FOR_TARGETS, a) }

     invalid_group:
         | '(' a=starred_expression ')' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use starred expression here") }
         | '(' a='**' expression ')' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use double starred expression here") }
     invalid_import:
         | a='import' ','.dotted_name+ 'from' dotted_name {
             RAISE_SYNTAX_ERROR_STARTING_FROM(a, "Did you mean to use 'from ... import ...' instead?") }
         | 'import' token=NEWLINE {
             RAISE_SYNTAX_ERROR_STARTING_FROM(token, "Expected one or more names after 'import'") }

     invalid_import_from_targets:
         | import_from_as_names ',' NEWLINE {
             RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") }
         | token=NEWLINE {
             RAISE_SYNTAX_ERROR_STARTING_FROM(token, "Expected one or more names after 'import'") }

     invalid_with_stmt:
         | ['async'] 'with' ','.(expression ['as' star_target])+ NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | ['async'] 'with' '(' ','.(expressions ['as' star_target])+ ','? ')' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
     invalid_with_stmt_indent:
         | ['async'] a='with' ','.(expression ['as' star_target])+ ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'with' statement on line %d", a->lineno) }
         | ['async'] a='with' '(' ','.(expressions ['as' star_target])+ ','? ')' ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'with' statement on line %d", a->lineno) }

     invalid_try_stmt:
         | a='try' ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'try' statement on line %d", a->lineno) }
         | 'try' ':' block !('except' | 'finally') { RAISE_SYNTAX_ERROR("expected 'except' or 'finally' block") }
         | 'try' ':' block* except_block+ a='except' b='*' expression ['as' NAME] ':' {
             RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot have both 'except' and 'except*' on the same 'try'") }
         | 'try' ':' block* except_star_block+ a='except' [expression ['as' NAME]] ':' {
             RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot have both 'except' and 'except*' on the same 'try'") }
     invalid_except_stmt:
         | 'except' '*'? a=expression ',' expressions ['as' NAME ] ':' {
             RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized") }
         | a='except' '*'? expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='except' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='except' '*' (NEWLINE | ':') { RAISE_SYNTAX_ERROR("expected one or more exception types") }
     invalid_finally_stmt:
         | a='finally' ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'finally' statement on line %d", a->lineno) }
     invalid_except_stmt_indent:
         | a='except' expression ['as' NAME ] ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'except' statement on line %d", a->lineno) }
         | a='except' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'except' statement on line %d", a->lineno) }
     invalid_except_star_stmt_indent:
         | a='except' '*' expression ['as' NAME ] ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'except*' statement on line %d", a->lineno) }
     invalid_match_stmt:
         | "match" subject_expr NEWLINE { CHECK_VERSION(void*, 10, "Pattern matching is", RAISE_SYNTAX_ERROR("expected ':'") ) }
         | a="match" subject=subject_expr ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'match' statement on line %d", a->lineno) }
     invalid_case_block:
         | "case" patterns guard? NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a="case" patterns guard? ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'case' statement on line %d", a->lineno) }
     invalid_as_pattern:
         | or_pattern 'as' a="_" { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use '_' as a target") }
         | or_pattern 'as' !NAME a=expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "invalid pattern target") }
     invalid_class_pattern:
         | name_or_attr '(' a=invalid_class_argument_pattern  { RAISE_SYNTAX_ERROR_KNOWN_RANGE(
             PyPegen_first_item(a, pattern_ty),
             PyPegen_last_item(a, pattern_ty),
             "positional patterns follow keyword patterns") }
     invalid_class_argument_pattern[asdl_pattern_seq*]:
         | [positional_patterns ','] keyword_patterns ',' a=positional_patterns { a }
     invalid_if_stmt:
         | 'if' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='if' a=named_expression ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'if' statement on line %d", a->lineno) }
     invalid_elif_stmt:
         | 'elif' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='elif' named_expression ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'elif' statement on line %d", a->lineno) }
     invalid_else_stmt:
         | a='else' ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'else' statement on line %d", a->lineno) }
     invalid_while_stmt:
         | 'while' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='while' named_expression ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'while' statement on line %d", a->lineno) }
     invalid_for_stmt:
         | ['async'] 'for' star_targets 'in' star_expressions NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | ['async'] a='for' star_targets 'in' star_expressions ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after 'for' statement on line %d", a->lineno) }
     invalid_def_raw:
         | ['async'] a='def' NAME [type_params] '(' [params] ')' ['->' expression] ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after function definition on line %d", a->lineno) }
         | ['async'] 'def' NAME [type_params] &&'(' [params] ')' ['->' expression] &&':' [func_type_comment] block
     invalid_class_def_raw:
         | 'class' NAME [type_params] ['(' [arguments] ')'] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
         | a='class' NAME [type_params] ['(' [arguments] ')'] ':' NEWLINE !INDENT {
             RAISE_INDENTATION_ERROR("expected an indented block after class definition on line %d", a->lineno) }

     invalid_double_starred_kvpairs:
         | ','.double_starred_kvpair+ ',' invalid_kvpair
         | expression ':' a='*' bitwise_or { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "cannot use a starred expression in a dictionary value") }
         | expression a=':' &('}'|',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") }
     invalid_kvpair:
         | a=expression !(':') {
             RAISE_ERROR_KNOWN_LOCATION(p, PyExc_SyntaxError, a->lineno, a->end_col_offset - 1, a->end_lineno, -1, "':' expected after dictionary key") }
         | expression ':' a='*' bitwise_or { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "cannot use a starred expression in a dictionary value") }
         | expression a=':' &('}'|',') {RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") }
     invalid_starred_expression:
         | a='*' expression '=' b=expression { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to iterable argument unpacking") }

     invalid_replacement_field:
         | '{' a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '='") }
         | '{' a='!' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '!'") }
         | '{' a=':' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before ':'") }
         | '{' a='}' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '}'") }
         | '{' !annotated_rhs { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting a valid expression after '{'")}
         | '{' annotated_rhs !('=' | '!' | ':' | '}') {
             PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '=', or '!', or ':', or '}'") }
         | '{' annotated_rhs '=' !('!' | ':' | '}') {
             PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '!', or ':', or '}'") }
         | '{' annotated_rhs '='? invalid_conversion_character
         | '{' annotated_rhs '='? ['!' NAME] !(':' | '}') {
             PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting ':' or '}'") }
         | '{' annotated_rhs '='? ['!' NAME] ':' fstring_format_spec* !'}' {
             PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '}', or format specs") }
         | '{' annotated_rhs '='? ['!' NAME] !'}' {
             PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '}'") }

     invalid_conversion_character:
         | '!' &(':' | '}') { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: missing conversion character") }
         | '!' !NAME { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: invalid conversion character") }

     invalid_arithmetic:
         | sum ('+'|'-'|'*'|'/'|'%'|'//'|'@') a='not' b=inversion { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "'not' after an operator must be parenthesized") }
     invalid_factor:
         | ('+' | '-' | '~') a='not' b=factor { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "'not' after an operator must be parenthesized") }

     invalid_type_params:
         | '[' token=']' {
             RAISE_SYNTAX_ERROR_STARTING_FROM(
                 token,
                 "Type parameter list cannot be empty")}

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Grammar/python.gram

   (2) https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form

   (3) https://en.wikipedia.org/wiki/Parsing_expression_grammar

   (4) https://peps.python.org/pep-0617/


File: python.info,  Node: The Python Standard Library,  Next: Extending and Embedding the Python Interpreter,  Prev: The Python Language Reference,  Up: Top

5 The Python Standard Library
*****************************

While *note The Python Language Reference: 145. describes the exact
syntax and semantics of the Python language, this library reference
manual describes the standard library that is distributed with Python.
It also describes some of the optional components that are commonly
included in Python distributions.

Python’s standard library is very extensive, offering a wide range of
facilities as indicated by the long table of contents listed below.  The
library contains built-in modules (written in C) that provide access to
system functionality such as file I/O that would otherwise be
inaccessible to Python programmers, as well as modules written in Python
that provide standardized solutions for many problems that occur in
everyday programming.  Some of these modules are explicitly designed to
encourage and enhance the portability of Python programs by abstracting
away platform-specifics into platform-neutral APIs.

The Python installers for the Windows platform usually include the
entire standard library and often also include many additional
components.  For Unix-like operating systems Python is normally provided
as a collection of packages, so it may be necessary to use the packaging
tools provided with the operating system to obtain some or all of the
optional components.

In addition to the standard library, there is an active collection of
hundreds of thousands of components (from individual programs and
modules to packages and entire application development frameworks),
available from the Python Package Index(1).

* Menu:

* Introduction: Introduction<6>.
* Built-in Functions::
* Built-in Constants::
* Built-in Types::
* Built-in Exceptions::
* Text Processing Services::
* Binary Data Services::
* Data Types::
* Numeric and Mathematical Modules::
* Functional Programming Modules::
* File and Directory Access::
* Data Persistence::
* Data Compression and Archiving::
* File Formats::
* Cryptographic Services::
* Generic Operating System Services::
* Command-line interface libraries::
* Concurrent Execution::
* Networking and Interprocess Communication::
* Internet Data Handling::
* Structured Markup Processing Tools::
* Internet Protocols and Support::
* Multimedia Services::
* Internationalization::
* Graphical user interfaces with Tk::
* Development Tools::
* Debugging and Profiling::
* Software Packaging and Distribution::
* Python Runtime Services::
* Custom Python Interpreters::
* Importing Modules::
* Python Language Services::
* MS Windows Specific Services::
* Unix-specific services::
* Modules command-line interface (CLI): Modules command-line interface CLI.
* Superseded Modules::
* Removed Modules::
* Security Considerations: Security Considerations<3>.

   ---------- Footnotes ----------

   (1) https://pypi.org


File: python.info,  Node: Introduction<6>,  Next: Built-in Functions,  Up: The Python Standard Library

5.1 Introduction
================

The “Python library” contains several different kinds of components.

It contains data types that would normally be considered part of the
“core” of a language, such as numbers and lists.  For these types, the
Python language core defines the form of literals and places some
constraints on their semantics, but does not fully define the semantics.
(On the other hand, the language core does define syntactic properties
like the spelling and priorities of operators.)

The library also contains built-in functions and exceptions — objects
that can be used by all Python code without the need of an *note import:
5e5. statement.  Some of these are defined by the core language, but
many are not essential for the core semantics and are only described
here.

The bulk of the library, however, consists of a collection of modules.
There are many ways to dissect this collection.  Some modules are
written in C and built in to the Python interpreter; others are written
in Python and imported in source form.  Some modules provide interfaces
that are highly specific to Python, like printing a stack trace; some
provide interfaces that are specific to particular operating systems,
such as access to specific hardware; others provide interfaces that are
specific to a particular application domain, like the World Wide Web.
Some modules are available in all versions and ports of Python; others
are only available when the underlying system supports or requires them;
yet others are available only when a particular configuration option was
chosen at the time when Python was compiled and installed.

This manual is organized “from the inside out:” it first describes the
built-in functions, data types and exceptions, and finally the modules,
grouped in chapters of related modules.

This means that if you start reading this manual from the start, and
skip to the next chapter when you get bored, you will get a reasonable
overview of the available modules and application areas that are
supported by the Python library.  Of course, you don’t 'have' to read it
like a novel — you can also browse the table of contents (in front of
the manual), or look for a specific function, module or term in the
index (in the back).  And finally, if you enjoy learning about random
subjects, you choose a random page number (see module *note random: b8.)
and read a section or two.  Regardless of the order in which you read
the sections of this manual, it helps to start with chapter *note
Built-in Functions: 12a3, as the remainder of the manual assumes
familiarity with this material.

Let the show begin!

* Menu:

* Notes on availability::


File: python.info,  Node: Notes on availability,  Up: Introduction<6>

5.1.1 Notes on availability
---------------------------

   * An “Availability: Unix” note means that this function is commonly
     found on Unix systems.  It does not make any claims about its
     existence on a specific operating system.

   * If not separately noted, all functions that claim “Availability:
     Unix” are supported on macOS, iOS and Android, all of which build
     on a Unix core.

   * If an availability note contains both a minimum Kernel version and
     a minimum libc version, then both conditions must hold.  For
     example a feature with note 'Availability: Linux >= 3.17 with glibc
     >= 2.27' requires both Linux 3.17 or newer and glibc 2.27 or newer.

* Menu:

* WebAssembly platforms::
* Mobile platforms::


File: python.info,  Node: WebAssembly platforms,  Next: Mobile platforms,  Up: Notes on availability

5.1.1.1 WebAssembly platforms
.............................

The WebAssembly(1) platforms ‘wasm32-emscripten’ (Emscripten(2)) and
‘wasm32-wasi’ (WASI(3)) provide a subset of POSIX APIs.  WebAssembly
runtimes and browsers are sandboxed and have limited access to the host
and external resources.  Any Python standard library module that uses
processes, threading, networking, signals, or other forms of
inter-process communication (IPC), is either not available or may not
work as on other Unix-like systems.  File I/O, file system, and Unix
permission-related functions are restricted, too.  Emscripten does not
permit blocking I/O. Other blocking operations like *note sleep(): 6a0.
block the browser event loop.

The properties and behavior of Python on WebAssembly platforms depend on
the Emscripten(4)-SDK or WASI(5)-SDK version, WASM runtimes (browser,
NodeJS, wasmtime(6)), and Python build time flags.  WebAssembly,
Emscripten, and WASI are evolving standards; some features like
networking may be supported in the future.

For Python in the browser, users should consider Pyodide(7) or
PyScript(8).  PyScript is built on top of Pyodide, which itself is built
on top of CPython and Emscripten.  Pyodide provides access to browsers’
JavaScript and DOM APIs as well as limited networking capabilities with
JavaScript’s ‘XMLHttpRequest’ and ‘Fetch’ APIs.

   * Process-related APIs are not available or always fail with an
     error.  That includes APIs that spawn new processes (*note fork():
     197, *note execve(): 113d.), wait for processes (*note waitpid():
     dc8.), send signals (*note kill(): 13b4.), or otherwise interact
     with processes.  The *note subprocess: d6. is importable but does
     not work.

   * The *note socket: cc. module is available, but is limited and
     behaves differently from other platforms.  On Emscripten, sockets
     are always non-blocking and require additional JavaScript code and
     helpers on the server to proxy TCP through WebSockets; see
     Emscripten Networking(9) for more information.  WASI snapshot
     preview 1 only permits sockets from an existing file descriptor.

   * Some functions are stubs that either don’t do anything and always
     return hardcoded values.

   * Functions related to file descriptors, file permissions, file
     ownership, and links are limited and don’t support some operations.
     For example, WASI does not permit symlinks with absolute file
     names.

   ---------- Footnotes ----------

   (1) https://webassembly.org/

   (2) https://emscripten.org/

   (3) https://wasi.dev/

   (4) https://emscripten.org/

   (5) https://wasi.dev/

   (6) https://wasmtime.dev/

   (7) https://pyodide.org/

   (8) https://pyscript.net/

   (9) https://emscripten.org/docs/porting/networking.html


File: python.info,  Node: Mobile platforms,  Prev: WebAssembly platforms,  Up: Notes on availability

5.1.1.2 Mobile platforms
........................

Android and iOS are, in most respects, POSIX operating systems.  File
I/O, socket handling, and threading all behave as they would on any
POSIX operating system.  However, there are several major differences:

   * Mobile platforms can only use Python in “embedded” mode.  There is
     no Python REPL, and no ability to use separate executables such as
     ‘python’ or ‘pip’.  To add Python code to your mobile app, you must
     use the *note Python embedding API: 1ffc.  For more details, see
     *note Using Python on Android: 1ffa. and *note Using Python on iOS:
     2002.

   * Subprocesses:

        * On Android, creating subprocesses is possible but officially
          unsupported(1).  In particular, Android does not support any
          part of the System V IPC API, so *note multiprocessing: 94. is
          not available.

        * An iOS app cannot use any form of subprocessing,
          multiprocessing, or inter-process communication.  If an iOS
          app attempts to create a subprocess, the process creating the
          subprocess will either lock up, or crash.  An iOS app has no
          visibility of other applications that are running, nor any
          ability to communicate with other running applications,
          outside of the iOS-specific APIs that exist for this purpose.

   * Mobile apps have limited access to modify system resources (such as
     the system clock).  These resources will often be 'readable', but
     attempts to modify those resources will usually fail.

   * Console input and output:

        * On Android, the native ‘stdout’ and ‘stderr’ are not connected
          to anything, so Python installs its own streams which redirect
          messages to the system log.  These can be seen under the tags
          ‘python.stdout’ and ‘python.stderr’ respectively.

        * iOS apps have a limited concept of console output.  ‘stdout’
          and ‘stderr’ 'exist', and content written to ‘stdout’ and
          ‘stderr’ will be visible in logs when running in Xcode, but
          this content 'won’t' be recorded in the system log.  If a user
          who has installed your app provides their app logs as a
          diagnostic aid, they will not include any detail written to
          ‘stdout’ or ‘stderr’.

        * Mobile apps have no usable ‘stdin’ at all.  While apps can
          display an on-screen keyboard, this is a software feature, not
          something that is attached to ‘stdin’.

          As a result, Python modules that involve console manipulation
          (such as *note curses: 2b. and *note readline: ba.) are not
          available on mobile platforms.

   ---------- Footnotes ----------

   (1) https://issuetracker.google.com/issues/128554619#comment4


File: python.info,  Node: Built-in Functions,  Next: Built-in Constants,  Prev: Introduction<6>,  Up: The Python Standard Library

5.2 Built-in Functions
======================

The Python interpreter has a number of functions and types built into it
that are always available.  They are listed here in alphabetical order.

Built-in Functions

--------------------------------------------------------------------------------------------------------------------
                                                                                      
     'A'                           'E'                         'L'                         'R'
     *note abs(): 1e45.            *note enumerate(): 14d0.     *note len(): 631.          *note range(): 2314.
     *note aiter(): 7d9.           *note eval(): 180.          *note list(): 2312.         *note repr(): 803.
     *note all(): 1470.            *note exec(): 17f.          *note locals(): 141.        *note reversed(): 86c.
     *note anext(): 7da.                                                                   *note round(): 1322.
     *note any(): 146f.            'F'                         'M'                         
     *note ascii(): 1434.          *note filter(): 86b.        *note map(): 86a.           'S'
                                   *note float(): 2f7.         *note max(): f40.           *note set(): 2315.
     'B'                           *note format(): 622.        *note memoryview(): 2313.     *note setattr(): 2316.
     *note bin(): 12f0.            *note frozenset(): 2311.     *note min(): f3f.          *note slice(): 46c.
     *note bool(): 46b.                                                                    *note sorted(): bed.
     *note breakpoint(): 234.      'G'                         'N'                         *note staticmethod(): 419.
     *note bytearray(): 1c4c.      *note getattr(): bf0.       *note next(): 7dc.          *note str(): 2317.
     *note bytes(): 1c4b.          *note globals(): 19ae.                                  *note sum(): 46d.
                                                               'O'                         *note super(): 4de.
     'C'                           'H'                         *note object(): a9b.        
     *note callable(): 120b.       *note hasattr(): 4d5.       *note oct(): 1316.          'T'
     *note chr(): 1785.            *note hash(): 5ee.          *note open(): 51f.          *note tuple(): 2318.
     *note classmethod(): 166.     *note help(): 8e0.          *note ord(): 209f.          *note type(): d71.
     *note compile(): 192.         *note hex(): 1317.                                      
     *note complex(): 2f8.                                     'P'                         'V'
                                   'I'                         *note pow(): 9dd.           *note vars(): 1bd2.
     'D'                           *note id(): 1471.           *note print(): fae.         
     *note delattr(): 230f.        *note input(): 1320.        *note property(): 194.      'Z'
     *note dict(): 2310.           *note int(): 257.                                       *note zip(): 7d4.
     *note dir(): 635.             *note isinstance(): 445.                                
     *note divmod(): 9ac.          *note issubclass(): 7c5.                                '_'
                                   *note iter(): 7db.                                      *note __import__(): 8dd.
                                                                                      

 -- Function: abs (number, /)

     Return the absolute value of a number.  The argument may be an
     integer, a floating-point number, or an object implementing *note
     __abs__(): 216a.  If the argument is a complex number, its
     magnitude is returned.

 -- Function: aiter (async_iterable, /)

     Return an *note asynchronous iterator: 1ab. for an *note
     asynchronous iterable: da2.  Equivalent to calling ‘x.__aiter__()’.

     Note: Unlike *note iter(): 7db, ‘aiter()’ has no 2-argument
     variant.

     Added in version 3.10.

 -- Function: all (iterable, /)

     Return ‘True’ if all elements of the 'iterable' are true (or if the
     iterable is empty).  Equivalent to:

          def all(iterable):
              for element in iterable:
                  if not element:
                      return False
              return True

 -- Function: awaitable anext (async_iterator, /)

 -- Function: awaitable anext (async_iterator, default, /)

     When awaited, return the next item from the given *note
     asynchronous iterator: 1ab, or 'default' if given and the iterator
     is exhausted.

     This is the async variant of the *note next(): 7dc. builtin, and
     behaves similarly.

     This calls the *note __anext__(): 1678. method of 'async_iterator',
     returning an *note awaitable: 1ad.  Awaiting this returns the next
     value of the iterator.  If 'default' is given, it is returned if
     the iterator is exhausted, otherwise *note StopAsyncIteration:
     1bbe. is raised.

     Added in version 3.10.

 -- Function: any (iterable, /)

     Return ‘True’ if any element of the 'iterable' is true.  If the
     iterable is empty, return ‘False’.  Equivalent to:

          def any(iterable):
              for element in iterable:
                  if element:
                      return True
              return False

 -- Function: ascii (object, /)

     As *note repr(): 803, return a string containing a printable
     representation of an object, but escape the non-ASCII characters in
     the string returned by ‘repr()’ using ‘\x’, ‘\u’, or ‘\U’ escapes.
     This generates a string similar to that returned by ‘repr()’ in
     Python 2.

 -- Function: bin (integer, /)

     Convert an integer number to a binary string prefixed with “0b”.
     The result is a valid Python expression.  If 'integer' is not a
     Python *note int: 257. object, it has to define an *note
     __index__(): 720. method that returns an integer.  Some examples:

          >>> bin(3)
          '0b11'
          >>> bin(-10)
          '-0b1010'

     If the prefix “0b” is desired or not, you can use either of the
     following ways.

          >>> format(14, '#b'), format(14, 'b')
          ('0b1110', '1110')
          >>> f'{14:#b}', f'{14:b}'
          ('0b1110', '1110')

     See also *note enum.bin(): 15d8. to represent negative values as
     twos-complement.

     See also *note format(): 622. for more information.

 -- Class: bool (object=False, /)

     Return a Boolean value, i.e.  one of ‘True’ or ‘False’.  The
     argument is converted using the standard *note truth testing
     procedure: 164c.  If the argument is false or omitted, this returns
     ‘False’; otherwise, it returns ‘True’.  The ‘bool’ class is a
     subclass of *note int: 257. (see *note Numeric Types — int, float,
     complex: 1d8d.).  It cannot be subclassed further.  Its only
     instances are ‘False’ and ‘True’ (see *note Boolean Type - bool:
     2319.).

     Changed in version 3.7: The parameter is now positional-only.

 -- Function: breakpoint (*args, **kws)

     This function drops you into the debugger at the call site.
     Specifically, it calls *note sys.breakpointhook(): af0, passing
     ‘args’ and ‘kws’ straight through.  By default,
     ‘sys.breakpointhook()’ calls *note pdb.set_trace(): 235. expecting
     no arguments.  In this case, it is purely a convenience function so
     you don’t have to explicitly import *note pdb: a5. or type as much
     code to enter the debugger.  However, ‘sys.breakpointhook()’ can be
     set to some other function and ‘breakpoint()’ will automatically
     call that, allowing you to drop into the debugger of choice.  If
     ‘sys.breakpointhook()’ is not accessible, this function will raise
     *note RuntimeError: 195.

     By default, the behavior of ‘breakpoint()’ can be changed with the
     *note PYTHONBREAKPOINT: af1. environment variable.  See *note
     sys.breakpointhook(): af0. for usage details.

     Note that this is not guaranteed if *note sys.breakpointhook():
     af0. has been replaced.

     Raises an *note auditing event: 1a15. ‘builtins.breakpoint’ with
     argument ‘breakpointhook’.

     Added in version 3.7.

 -- Class: bytearray (source=b'')

 -- Class: bytearray (source, encoding, errors='strict')

     Return a new array of bytes.  The ‘bytearray’ class is a mutable
     sequence of integers in the range 0 <= x < 256.  It has most of the
     usual methods of mutable sequences, described in *note Mutable
     Sequence Types: 231a, as well as most methods that the *note bytes:
     1c2. type has, see *note Bytes and Bytearray Operations: 231b.

     The optional 'source' parameter can be used to initialize the array
     in a few different ways:

        * If it is a 'string', you must also give the 'encoding' (and
          optionally, 'errors') parameters; *note bytearray(): 2ea. then
          converts the string to bytes using *note str.encode(): 8de.

        * If it is an 'integer', the array will have that size and will
          be initialized with null bytes.

        * If it is an object conforming to the *note buffer interface:
          2e8, a read-only buffer of the object will be used to
          initialize the bytes array.

        * If it is an 'iterable', it must be an iterable of integers in
          the range ‘0 <= x < 256’, which are used as the initial
          contents of the array.

     Without an argument, an array of size 0 is created.

     See also *note Binary Sequence Types — bytes, bytearray,
     memoryview: 231c. and *note Bytearray Objects: 231d.

 -- Class: bytes (source=b'')

 -- Class: bytes (source, encoding, errors='strict')

     Return a new “bytes” object which is an immutable sequence of
     integers in the range ‘0 <= x < 256’.  ‘bytes’ is an immutable
     version of *note bytearray: 2ea. – it has the same non-mutating
     methods and the same indexing and slicing behavior.

     Accordingly, constructor arguments are interpreted as for *note
     bytearray(): 2ea.

     Bytes objects can also be created with literals, see *note String
     and Bytes literals: 2050.

     See also *note Binary Sequence Types — bytes, bytearray,
     memoryview: 231c, *note Bytes Objects: 231e, and *note Bytes and
     Bytearray Operations: 231b.

 -- Function: callable (object, /)

     Return *note True: c2d. if the 'object' argument appears callable,
     *note False: b4f. if not.  If this returns ‘True’, it is still
     possible that a call fails, but if it is ‘False’, calling 'object'
     will never succeed.  Note that classes are callable (calling a
     class returns a new instance); instances are callable if their
     class has a *note __call__(): 55b. method.

     Added in version 3.2: This function was first removed in Python 3.0
     and then brought back in Python 3.2.

 -- Function: chr (codepoint, /)

     Return the string representing a character with the specified
     Unicode code point.  For example, ‘chr(97)’ returns the string
     ‘'a'’, while ‘chr(8364)’ returns the string ‘'€'’.  This is the
     inverse of *note ord(): 209f.

     The valid range for the argument is from 0 through 1,114,111
     (0x10FFFF in base 16).  *note ValueError: 202. will be raised if it
     is outside that range.

 -- Function: @classmethod

     Transform a method into a class method.

     A class method receives the class as an implicit first argument,
     just like an instance method receives the instance.  To declare a
     class method, use this idiom:

          class C:
              @classmethod
              def f(cls, arg1, arg2): ...

     The ‘@classmethod’ form is a function *note decorator: 734. – see
     *note Function definitions: 1dce. for details.

     A class method can be called either on the class (such as ‘C.f()’)
     or on an instance (such as ‘C().f()’).  The instance is ignored
     except for its class.  If a class method is called for a derived
     class, the derived class object is passed as the implied first
     argument.

     Class methods are different than C++ or Java static methods.  If
     you want those, see *note staticmethod(): 419. in this section.
     For more information on class methods, see *note The standard type
     hierarchy: 2094.

     Changed in version 3.9: Class methods can now wrap other *note
     descriptors: 1677. such as *note property(): 194.

     Changed in version 3.10: Class methods now inherit the method
     attributes (*note __module__: 20ad, *note __name__: 131c, *note
     __qualname__: 20ac, *note __doc__: 121e. and *note __annotations__:
     121d.) and have a new ‘__wrapped__’ attribute.

     Deprecated since version 3.11, removed in version 3.13: Class
     methods can no longer wrap other *note descriptors: 1677. such as
     *note property(): 194.

 -- Function: compile (source, filename, mode, flags=0,
          dont_inherit=False, optimize=-1)

     Compile the 'source' into a code or AST object.  Code objects can
     be executed by *note exec(): 17f. or *note eval(): 180.  'source'
     can either be a normal string, a byte string, or an AST object.
     Refer to the *note ast: 8. module documentation for information on
     how to work with AST objects.

     The 'filename' argument should give the file from which the code
     was read; pass some recognizable value if it wasn’t read from a
     file (‘'<string>'’ is commonly used).

     The 'mode' argument specifies what kind of code must be compiled;
     it can be ‘'exec'’ if 'source' consists of a sequence of
     statements, ‘'eval'’ if it consists of a single expression, or
     ‘'single'’ if it consists of a single interactive statement (in the
     latter case, expression statements that evaluate to something other
     than ‘None’ will be printed).

     The optional arguments 'flags' and 'dont_inherit' control which
     *note compiler options: 231f. should be activated and which *note
     future features: 189. should be allowed.  If neither is present (or
     both are zero) the code is compiled with the same flags that affect
     the code that is calling ‘compile()’.  If the 'flags' argument is
     given and 'dont_inherit' is not (or is zero) then the compiler
     options and the future statements specified by the 'flags' argument
     are used in addition to those that would be used anyway.  If
     'dont_inherit' is a non-zero integer then the 'flags' argument is
     it – the flags (future features and compiler options) in the
     surrounding code are ignored.

     Compiler options and future statements are specified by bits which
     can be bitwise ORed together to specify multiple options.  The
     bitfield required to specify a given future feature can be found as
     the *note compiler_flag: 20fb. attribute on the *note _Feature:
     2320. instance in the *note __future__: 0. module.  *note Compiler
     flags: 231f. can be found in *note ast: 8. module, with ‘PyCF_’
     prefix.

     The argument 'optimize' specifies the optimization level of the
     compiler; the default value of ‘-1’ selects the optimization level
     of the interpreter as given by *note -O: de3. options.  Explicit
     levels are ‘0’ (no optimization; ‘__debug__’ is true), ‘1’ (asserts
     are removed, ‘__debug__’ is false) or ‘2’ (docstrings are removed
     too).

     This function raises *note SyntaxError: 18d. or *note ValueError:
     202. if the compiled source is invalid.

     If you want to parse Python code into its AST representation, see
     *note ast.parse(): 1a8.

     Raises an *note auditing event: 1a15. ‘compile’ with arguments
     ‘source’ and ‘filename’.  This event may also be raised by implicit
     compilation.

          Note: When compiling a string with multi-line code in
          ‘'single'’ or ‘'eval'’ mode, input must be terminated by at
          least one newline character.  This is to facilitate detection
          of incomplete and complete statements in the *note code: 1a.
          module.

          Warning: It is possible to crash the Python interpreter with a
          sufficiently large/complex string when compiling to an AST
          object due to stack depth limitations in Python’s AST
          compiler.

     Changed in version 3.2: Allowed use of Windows and Mac newlines.
     Also, input in ‘'exec'’ mode does not have to end in a newline
     anymore.  Added the 'optimize' parameter.

     Changed in version 3.5: Previously, *note TypeError: 2c3. was
     raised when null bytes were encountered in 'source'.

     Added in version 3.8: ‘ast.PyCF_ALLOW_TOP_LEVEL_AWAIT’ can now be
     passed in flags to enable support for top-level ‘await’, ‘async
     for’, and ‘async with’.

 -- Class: complex (number=0, /)

 -- Class: complex (string, /)

 -- Class: complex (real=0, imag=0)

     Convert a single string or number to a complex number, or create a
     complex number from real and imaginary parts.

     Examples:

          >>> complex('+1.23')
          (1.23+0j)
          >>> complex('-4.5j')
          -4.5j
          >>> complex('-1.23+4.5j')
          (-1.23+4.5j)
          >>> complex('\t( -1.23+4.5J )\n')
          (-1.23+4.5j)
          >>> complex('-Infinity+NaNj')
          (-inf+nanj)
          >>> complex(1.23)
          (1.23+0j)
          >>> complex(imag=-4.5)
          -4.5j
          >>> complex(-1.23, 4.5)
          (-1.23+4.5j)

     If the argument is a string, it must contain either a real part (in
     the same format as for *note float(): 2f7.) or an imaginary part
     (in the same format but with a ‘'j'’ or ‘'J'’ suffix), or both real
     and imaginary parts (the sign of the imaginary part is mandatory in
     this case).  The string can optionally be surrounded by whitespaces
     and the round parentheses ‘'('’ and ‘')'’, which are ignored.  The
     string must not contain whitespace between ‘'+'’, ‘'-'’, the ‘'j'’
     or ‘'J'’ suffix, and the decimal number.  For example,
     ‘complex('1+2j')’ is fine, but ‘complex('1 + 2j')’ raises *note
     ValueError: 202.  More precisely, the input must conform to the
     *note complexvalue: 2321. production rule in the following grammar,
     after parentheses and leading and trailing whitespace characters
     are removed:

          complexvalue ::= *note floatvalue: 2322. |
                           *note floatvalue: 2322. ("j" | "J") |
                           *note floatvalue: 2322. *note sign: 2323. *note absfloatvalue: 2324. ("j" | "J")

     If the argument is a number, the constructor serves as a numeric
     conversion like *note int: 257. and *note float: 2f7.  For a
     general Python object ‘x’, ‘complex(x)’ delegates to
     ‘x.__complex__()’.  If *note __complex__(): 5ea. is not defined
     then it falls back to *note __float__(): 9d7.  If ‘__float__()’ is
     not defined then it falls back to *note __index__(): 720.

     If two arguments are provided or keyword arguments are used, each
     argument may be any numeric type (including complex).  If both
     arguments are real numbers, return a complex number with the real
     component 'real' and the imaginary component 'imag'.  If both
     arguments are complex numbers, return a complex number with the
     real component ‘real.real-imag.imag’ and the imaginary component
     ‘real.imag+imag.real’.  If one of arguments is a real number, only
     its real component is used in the above expressions.

     If all arguments are omitted, returns ‘0j’.

     The complex type is described in *note Numeric Types — int, float,
     complex: 1d8d.

     Changed in version 3.6: Grouping digits with underscores as in code
     literals is allowed.

     Changed in version 3.8: Falls back to *note __index__(): 720. if
     *note __complex__(): 5ea. and *note __float__(): 9d7. are not
     defined.

 -- Function: delattr (object, name, /)

     This is a relative of *note setattr(): 2316.  The arguments are an
     object and a string.  The string must be the name of one of the
     object’s attributes.  The function deletes the named attribute,
     provided the object allows it.  For example, ‘delattr(x, 'foobar')’
     is equivalent to ‘del x.foobar’.  'name' need not be a Python
     identifier (see ‘setattr()’).

 -- Class: dict (**kwargs)

 -- Class: dict (mapping, /, **kwargs)

 -- Class: dict (iterable, /, **kwargs)

     Create a new dictionary.  The ‘dict’ object is the dictionary
     class.  See ‘dict’ and *note Mapping Types — dict: adc. for
     documentation about this class.

     For other containers see the built-in *note list: 614, *note set:
     5dc, and *note tuple: 373. classes, as well as the *note
     collections: 1d. module.

 -- Function: dir ()

 -- Function: dir (object, /)

     Without arguments, return the list of names in the current local
     scope.  With an argument, attempt to return a list of valid
     attributes for that object.

     If the object has a method named *note __dir__(): 15b7, this method
     will be called and must return the list of attributes.  This allows
     objects that implement a custom *note __getattr__(): 4d6. or *note
     __getattribute__(): bf1. function to customize the way ‘dir()’
     reports their attributes.

     If the object does not provide *note __dir__(): 15b7, the function
     tries its best to gather information from the object’s *note
     __dict__: 55e. attribute, if defined, and from its type object.
     The resulting list is not necessarily complete and may be
     inaccurate when the object has a custom *note __getattr__(): 4d6.

     The default ‘dir()’ mechanism behaves differently with different
     types of objects, as it attempts to produce the most relevant,
     rather than complete, information:

        * If the object is a module object, the list contains the names
          of the module’s attributes.

        * If the object is a type or class object, the list contains the
          names of its attributes, and recursively of the attributes of
          its bases.

        * Otherwise, the list contains the object’s attributes’ names,
          the names of its class’s attributes, and recursively of the
          attributes of its class’s base classes.

     The resulting list is sorted alphabetically.  For example:

          >>> import struct
          >>> dir()   # show the names in the module namespace
          ['__builtins__', '__name__', 'struct']
          >>> dir(struct)   # show the names in the struct module
          ['Struct', '__all__', '__builtins__', '__cached__', '__doc__', '__file__',
           '__initializing__', '__loader__', '__name__', '__package__',
           '_clearcache', 'calcsize', 'error', 'pack', 'pack_into',
           'unpack', 'unpack_from']
          >>> class Shape:
          ...     def __dir__(self):
          ...         return ['area', 'perimeter', 'location']
          ...
          >>> s = Shape()
          >>> dir(s)
          ['area', 'location', 'perimeter']

          Note: Because ‘dir()’ is supplied primarily as a convenience
          for use at an interactive prompt, it tries to supply an
          interesting set of names more than it tries to supply a
          rigorously or consistently defined set of names, and its
          detailed behavior may change across releases.  For example,
          metaclass attributes are not in the result list when the
          argument is a class.

 -- Function: divmod (a, b, /)

     Take two (non-complex) numbers as arguments and return a pair of
     numbers consisting of their quotient and remainder when using
     integer division.  With mixed operand types, the rules for binary
     arithmetic operators apply.  For integers, the result is the same
     as ‘(a // b, a % b)’.  For floating-point numbers the result is
     ‘(q, a % b)’, where 'q' is usually ‘math.floor(a / b)’ but may be 1
     less than that.  In any case ‘q * b + a % b’ is very close to 'a',
     if ‘a % b’ is non-zero it has the same sign as 'b', and ‘0 <= abs(a
     % b) < abs(b)’.

 -- Function: enumerate (iterable, start=0)

     Return an enumerate object.  'iterable' must be a sequence, an
     *note iterator: 1ac, or some other object which supports iteration.
     The *note __next__(): 1315. method of the iterator returned by
     ‘enumerate()’ returns a tuple containing a count (from 'start'
     which defaults to 0) and the values obtained from iterating over
     'iterable'.

          >>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']
          >>> list(enumerate(seasons))
          [(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
          >>> list(enumerate(seasons, start=1))
          [(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]

     Equivalent to:

          def enumerate(iterable, start=0):
              n = start
              for elem in iterable:
                  yield n, elem
                  n += 1

 -- Function: eval (source, /, globals=None, locals=None)


     Parameters:

        * ‘source’ (*note str: 44f. | *note code object: 1d2.) – A
          Python expression.

        * ‘globals’ (*note dict: 256. | ‘None’) – The global namespace
          (default: ‘None’).

        * ‘locals’ (*note mapping: 1200. | ‘None’) – The local namespace
          (default: ‘None’).


     Returns: The result of the evaluated expression.


     Raises: Syntax errors are reported as exceptions.

          Warning: This function executes arbitrary code.  Calling it
          with untrusted user-supplied input will lead to security
          vulnerabilities.

     The 'source' argument is parsed and evaluated as a Python
     expression (technically speaking, a condition list) using the
     'globals' and 'locals' mappings as global and local namespace.  If
     the 'globals' dictionary is present and does not contain a value
     for the key ‘__builtins__’, a reference to the dictionary of the
     built-in module *note builtins: 12. is inserted under that key
     before 'source' is parsed.  Overriding ‘__builtins__’ can be used
     to restrict or change the available names, but this is 'not' a
     security mechanism: the executed code can still access all
     builtins.  If the 'locals' mapping is omitted it defaults to the
     'globals' dictionary.  If both mappings are omitted, the source is
     executed with the 'globals' and 'locals' in the environment where
     ‘eval()’ is called.  Note, 'eval()' will only have access to the
     *note nested scopes: 20f3. (non-locals) in the enclosing
     environment if they are already referenced in the scope that is
     calling ‘eval()’ (e.g.  via a *note nonlocal: 12ef. statement).

     Example:

          >>> x = 1
          >>> eval('x+1')
          2

     This function can also be used to execute arbitrary code objects
     (such as those created by *note compile(): 192.).  In this case,
     pass a code object instead of a string.  If the code object has
     been compiled with ‘'exec'’ as the 'mode' argument, ‘eval()’'s
     return value will be ‘None’.

     Hints: dynamic execution of statements is supported by the *note
     exec(): 17f. function.  The *note globals(): 19ae. and *note
     locals(): 141. functions return the current global and local
     dictionary, respectively, which may be useful to pass around for
     use by ‘eval()’ or ‘exec()’.

     If the given source is a string, then leading and trailing spaces
     and tabs are stripped.

     See *note ast.literal_eval(): c38. for a function that can safely
     evaluate strings with expressions containing only literals.

     Raises an *note auditing event: 1a15. ‘exec’ with the code object
     as the argument.  Code compilation events may also be raised.

     Changed in version 3.13: The 'globals' and 'locals' arguments can
     now be passed as keywords.

     Changed in version 3.13: The semantics of the default 'locals'
     namespace have been adjusted as described for the *note locals():
     141. builtin.

 -- Function: exec (source, /, globals=None, locals=None, *,
          closure=None)

          Warning: This function executes arbitrary code.  Calling it
          with untrusted user-supplied input will lead to security
          vulnerabilities.

     This function supports dynamic execution of Python code.  'source'
     must be either a string or a code object.  If it is a string, the
     string is parsed as a suite of Python statements which is then
     executed (unless a syntax error occurs).  (1)  If it is a code
     object, it is simply executed.  In all cases, the code that’s
     executed is expected to be valid as file input (see the section
     *note File input: 22f6. in the Reference Manual).  Be aware that
     the *note nonlocal: 12ef, *note yield: 9d8, and *note return: 9d9.
     statements may not be used outside of function definitions even
     within the context of code passed to the ‘exec()’ function.  The
     return value is ‘None’.

     In all cases, if the optional parts are omitted, the code is
     executed in the current scope.  If only 'globals' is provided, it
     must be a dictionary (and not a subclass of dictionary), which will
     be used for both the global and the local variables.  If 'globals'
     and 'locals' are given, they are used for the global and local
     variables, respectively.  If provided, 'locals' can be any mapping
     object.  Remember that at the module level, globals and locals are
     the same dictionary.

          Note: When ‘exec’ gets two separate objects as 'globals' and
          'locals', the code will be executed as if it were embedded in
          a class definition.  This means functions and classes defined
          in the executed code will not be able to access variables
          assigned at the top level (as the “top level” variables are
          treated as class variables in a class definition).

     If the 'globals' dictionary does not contain a value for the key
     ‘__builtins__’, a reference to the dictionary of the built-in
     module *note builtins: 12. is inserted under that key.  Overriding
     ‘__builtins__’ can be used to restrict or change the available
     names, but this is 'not' a security mechanism: the executed code
     can still access all builtins.

     The 'closure' argument specifies a closure–a tuple of cellvars.
     It’s only valid when the 'object' is a code object containing *note
     free (closure) variables: 20f4.  The length of the tuple must
     exactly match the length of the code object’s *note co_freevars:
     20aa. attribute.

     Raises an *note auditing event: 1a15. ‘exec’ with the code object
     as the argument.  Code compilation events may also be raised.

          Note: The built-in functions *note globals(): 19ae. and *note
          locals(): 141. return the current global and local namespace,
          respectively, which may be useful to pass around for use as
          the second and third argument to ‘exec()’.

          Note: The default 'locals' act as described for function *note
          locals(): 141. below.  Pass an explicit 'locals' dictionary if
          you need to see effects of the code on 'locals' after function
          ‘exec()’ returns.

     Changed in version 3.11: Added the 'closure' parameter.

     Changed in version 3.13: The 'globals' and 'locals' arguments can
     now be passed as keywords.

     Changed in version 3.13: The semantics of the default 'locals'
     namespace have been adjusted as described for the *note locals():
     141. builtin.

 -- Function: filter (function, iterable, /)

     Construct an iterator from those elements of 'iterable' for which
     'function' is true.  'iterable' may be either a sequence, a
     container which supports iteration, or an iterator.  If 'function'
     is ‘None’, the identity function is assumed, that is, all elements
     of 'iterable' that are false are removed.

     Note that ‘filter(function, iterable)’ is equivalent to the
     generator expression ‘(item for item in iterable if
     function(item))’ if function is not ‘None’ and ‘(item for item in
     iterable if item)’ if function is ‘None’.

     See *note itertools.filterfalse(): 2326. for the complementary
     function that returns elements of 'iterable' for which 'function'
     is false.

 -- Class: float (number=0.0, /)

 -- Class: float (string, /)

     Return a floating-point number constructed from a number or a
     string.

     Examples:

          >>> float('+1.23')
          1.23
          >>> float('   -12345\n')
          -12345.0
          >>> float('1e-003')
          0.001
          >>> float('+1E6')
          1000000.0
          >>> float('-Infinity')
          -inf

     If the argument is a string, it should contain a decimal number,
     optionally preceded by a sign, and optionally embedded in
     whitespace.  The optional sign may be ‘'+'’ or ‘'-'’; a ‘'+'’ sign
     has no effect on the value produced.  The argument may also be a
     string representing a NaN (not-a-number), or positive or negative
     infinity.  More precisely, the input must conform to the *note
     floatvalue: 2322. production rule in the following grammar, after
     leading and trailing whitespace characters are removed:

          sign          ::= "+" | "-"
          infinity      ::= "Infinity" | "inf"
          nan           ::= "nan"
          digit         ::= <a Unicode decimal digit, i.e. characters in Unicode general category Nd>
          digitpart     ::= *note digit: 2329. (["_"] *note digit: 2329.)*
          number        ::= [*note digitpart: 232a.] "." *note digitpart: 232a. | *note digitpart: 232a. ["."]
          exponent      ::= ("e" | "E") [*note sign: 2323.] *note digitpart: 232a.
          floatnumber   ::= *note number: 232b. [*note exponent: 232c.]
          absfloatvalue ::= *note floatnumber: 232d. | *note infinity: 2327. | *note nan: 2328.
          floatvalue    ::= [*note sign: 2323.] *note absfloatvalue: 2324.

     Case is not significant, so, for example, “inf”, “Inf”, “INFINITY”,
     and “iNfINity” are all acceptable spellings for positive infinity.

     Otherwise, if the argument is an integer or a floating-point
     number, a floating-point number with the same value (within
     Python’s floating-point precision) is returned.  If the argument is
     outside the range of a Python float, an *note OverflowError: 888.
     will be raised.

     For a general Python object ‘x’, ‘float(x)’ delegates to
     ‘x.__float__()’.  If *note __float__(): 9d7. is not defined then it
     falls back to *note __index__(): 720.

     If no argument is given, ‘0.0’ is returned.

     The float type is described in *note Numeric Types — int, float,
     complex: 1d8d.

     Changed in version 3.6: Grouping digits with underscores as in code
     literals is allowed.

     Changed in version 3.7: The parameter is now positional-only.

     Changed in version 3.8: Falls back to *note __index__(): 720. if
     *note __float__(): 9d7. is not defined.

 -- Function: format (value, format_spec='', /)

     Convert a 'value' to a “formatted” representation, as controlled by
     'format_spec'.  The interpretation of 'format_spec' will depend on
     the type of the 'value' argument; however, there is a standard
     formatting syntax that is used by most built-in types: *note Format
     specification mini-language: 1e8.

     The default 'format_spec' is an empty string which usually gives
     the same effect as calling *note str(value): 44f.

     A call to ‘format(value, format_spec)’ is translated to
     ‘type(value).__format__(value, format_spec)’ which bypasses the
     instance dictionary when searching for the value’s *note
     __format__(): 621. method.  A *note TypeError: 2c3. exception is
     raised if the method search reaches *note object: a9b. and the
     'format_spec' is non-empty, or if either the 'format_spec' or the
     return value are not strings.

     Changed in version 3.4: ‘object().__format__(format_spec)’ raises
     *note TypeError: 2c3. if 'format_spec' is not an empty string.

 -- Class: frozenset (iterable=(), /)

     Return a new ‘frozenset’ object, optionally with elements taken
     from 'iterable'.  ‘frozenset’ is a built-in class.  See ‘frozenset’
     and *note Set Types — set, frozenset: 1de7. for documentation about
     this class.

     For other containers see the built-in *note set: 5dc, *note list:
     614, *note tuple: 373, and *note dict: 256. classes, as well as the
     *note collections: 1d. module.

 -- Function: getattr (object, name, /)

 -- Function: getattr (object, name, default, /)

     Return the value of the named attribute of 'object'.  'name' must
     be a string.  If the string is the name of one of the object’s
     attributes, the result is the value of that attribute.  For
     example, ‘getattr(x, 'foobar')’ is equivalent to ‘x.foobar’.  If
     the named attribute does not exist, 'default' is returned if
     provided, otherwise *note AttributeError: 34e. is raised.  'name'
     need not be a Python identifier (see *note setattr(): 2316.).

          Note: Since *note private name mangling: 1e5b. happens at
          compilation time, one must manually mangle a private
          attribute’s (attributes with two leading underscores) name in
          order to retrieve it with ‘getattr()’.

 -- Function: globals ()

     Return the dictionary implementing the current module namespace.
     For code within functions, this is set when the function is defined
     and remains the same regardless of where the function is called.

 -- Function: hasattr (object, name, /)

     The arguments are an object and a string.  The result is ‘True’ if
     the string is the name of one of the object’s attributes, ‘False’
     if not.  (This is implemented by calling ‘getattr(object, name)’
     and seeing whether it raises an *note AttributeError: 34e. or not.)

 -- Function: hash (object, /)

     Return the hash value of the object (if it has one).  Hash values
     are integers.  They are used to quickly compare dictionary keys
     during a dictionary lookup.  Numeric values that compare equal have
     the same hash value (even if they are of different types, as is the
     case for 1 and 1.0).

          Note: For objects with custom *note __hash__(): b14. methods,
          note that ‘hash()’ truncates the return value based on the bit
          width of the host machine.

 -- Function: help ()

 -- Function: help (request)

     Invoke the built-in help system.  (This function is intended for
     interactive use.)  If no argument is given, the interactive help
     system starts on the interpreter console.  If the argument is a
     string, then the string is looked up as the name of a module,
     function, class, method, keyword, or documentation topic, and a
     help page is printed on the console.  If the argument is any other
     kind of object, a help page on the object is generated.

     Note that if a slash(/) appears in the parameter list of a function
     when invoking ‘help()’, it means that the parameters prior to the
     slash are positional-only.  For more info, see *note the FAQ entry
     on positional-only parameters: 232e.

     This function is added to the built-in namespace by the *note site:
     c7. module.

     Changed in version 3.4: Changes to *note pydoc: b5. and *note
     inspect: 7e. mean that the reported signatures for callables are
     now more comprehensive and consistent.

 -- Function: hex (integer, /)

     Convert an integer number to a lowercase hexadecimal string
     prefixed with “0x”.  If 'integer' is not a Python *note int: 257.
     object, it has to define an *note __index__(): 720. method that
     returns an integer.  Some examples:

          >>> hex(255)
          '0xff'
          >>> hex(-42)
          '-0x2a'

     If you want to convert an integer number to an uppercase or lower
     hexadecimal string with prefix or not, you can use either of the
     following ways:

          >>> '%#x' % 255, '%x' % 255, '%X' % 255
          ('0xff', 'ff', 'FF')
          >>> format(255, '#x'), format(255, 'x'), format(255, 'X')
          ('0xff', 'ff', 'FF')
          >>> f'{255:#x}', f'{255:x}', f'{255:X}'
          ('0xff', 'ff', 'FF')

     See also *note format(): 622. for more information.

     See also *note int(): 257. for converting a hexadecimal string to
     an integer using a base of 16.

          Note: To obtain a hexadecimal string representation for a
          float, use the *note float.hex(): 1eba. method.

 -- Function: id (object, /)

     Return the “identity” of an object.  This is an integer which is
     guaranteed to be unique and constant for this object during its
     lifetime.  Two objects with non-overlapping lifetimes may have the
     same ‘id()’ value.

     'CPython implementation detail:' This is the address of the object
     in memory.

     Raises an *note auditing event: 1a15. ‘builtins.id’ with argument
     ‘id’.

 -- Function: input ()

 -- Function: input (prompt, /)

     If the 'prompt' argument is present, it is written to standard
     output without a trailing newline.  The function then reads a line
     from input, converts it to a string (stripping a trailing newline),
     and returns that.  When EOF is read, *note EOFError: 1321. is
     raised.  Example:

          >>> s = input('--> ')
          --> Monty Python's Flying Circus
          >>> s
          "Monty Python's Flying Circus"

     If the *note readline: ba. module was loaded, then ‘input()’ will
     use it to provide elaborate line editing and history features.

     Raises an *note auditing event: 1a15. ‘builtins.input’ with
     argument ‘prompt’ before reading input

     Raises an *note auditing event: 1a15. ‘builtins.input/result’ with
     the result after successfully reading input.

 -- Class: int (number=0, /)

 -- Class: int (string, /, base=10)

     Return an integer object constructed from a number or a string, or
     return ‘0’ if no arguments are given.

     Examples:

          >>> int(123.45)
          123
          >>> int('123')
          123
          >>> int('   -12_345\n')
          -12345
          >>> int('FACE', 16)
          64206
          >>> int('0xface', 0)
          64206
          >>> int('01110011', base=2)
          115

     If the argument defines *note __int__(): 71f, ‘int(x)’ returns
     ‘x.__int__()’.  If the argument defines *note __index__(): 720, it
     returns ‘x.__index__()’.  If the argument defines *note
     __trunc__(): 71e, it returns ‘x.__trunc__()’.  For floating-point
     numbers, this truncates towards zero.

     If the argument is not a number or if 'base' is given, then it must
     be a string, *note bytes: 1c2, or *note bytearray: 2ea. instance
     representing an integer in radix 'base'.  Optionally, the string
     can be preceded by ‘+’ or ‘-’ (with no space in between), have
     leading zeros, be surrounded by whitespace, and have single
     underscores interspersed between digits.

     A base-n integer string contains digits, each representing a value
     from 0 to n-1.  The values 0–9 can be represented by any Unicode
     decimal digit.  The values 10–35 can be represented by ‘a’ to ‘z’
     (or ‘A’ to ‘Z’).  The default 'base' is 10.  The allowed bases are
     0 and 2–36.  Base-2, -8, and -16 strings can be optionally prefixed
     with ‘0b’/‘0B’, ‘0o’/‘0O’, or ‘0x’/‘0X’, as with integer literals
     in code.  For base 0, the string is interpreted in a similar way to
     an *note integer literal in code: 2074, in that the actual base is
     2, 8, 10, or 16 as determined by the prefix.  Base 0 also disallows
     leading zeros: ‘int('010', 0)’ is not legal, while ‘int('010')’ and
     ‘int('010', 8)’ are.

     The integer type is described in *note Numeric Types — int, float,
     complex: 1d8d.

     Changed in version 3.4: If 'base' is not an instance of ‘int’ and
     the 'base' object has a *note base.__index__: 720. method, that
     method is called to obtain an integer for the base.  Previous
     versions used *note base.__int__: 71f. instead of ‘base.__index__’.

     Changed in version 3.6: Grouping digits with underscores as in code
     literals is allowed.

     Changed in version 3.7: The first parameter is now positional-only.

     Changed in version 3.8: Falls back to *note __index__(): 720. if
     *note __int__(): 71f. is not defined.

     Changed in version 3.11: The delegation to *note __trunc__(): 71e.
     is deprecated.

     Changed in version 3.11: ‘int’ string inputs and string
     representations can be limited to help avoid denial of service
     attacks.  A *note ValueError: 202. is raised when the limit is
     exceeded while converting a string to an ‘int’ or when converting
     an ‘int’ into a string would exceed the limit.  See the *note
     integer string conversion length limitation: 5f8. documentation.

 -- Function: isinstance (object, classinfo, /)

     Return ‘True’ if the 'object' argument is an instance of the
     'classinfo' argument, or of a (direct, indirect, or *note virtual:
     11fa.) subclass thereof.  If 'object' is not an object of the given
     type, the function always returns ‘False’.  If 'classinfo' is a
     tuple of type objects (or recursively, other such tuples) or a
     *note Union Type: 7c6. of multiple types, return ‘True’ if 'object'
     is an instance of any of the types.  If 'classinfo' is not a type
     or tuple of types and such tuples, a *note TypeError: 2c3.
     exception is raised.  ‘TypeError’ may not be raised for an invalid
     type if an earlier check succeeds.

     Changed in version 3.10: 'classinfo' can be a *note Union Type:
     7c6.

 -- Function: issubclass (class, classinfo, /)

     Return ‘True’ if 'class' is a subclass (direct, indirect, or *note
     virtual: 11fa.) of 'classinfo'.  A class is considered a subclass
     of itself.  'classinfo' may be a tuple of class objects (or
     recursively, other such tuples) or a *note Union Type: 7c6, in
     which case return ‘True’ if 'class' is a subclass of any entry in
     'classinfo'.  In any other case, a *note TypeError: 2c3. exception
     is raised.

     Changed in version 3.10: 'classinfo' can be a *note Union Type:
     7c6.

 -- Function: iter (iterable, /)

 -- Function: iter (callable, sentinel, /)

     Return an *note iterator: 1ac. object.  The first argument is
     interpreted very differently depending on the presence of the
     second argument.  Without a second argument, the single argument
     must be a collection object which supports the *note iterable:
     126d. protocol (the *note __iter__(): c90. method), or it must
     support the sequence protocol (the *note __getitem__(): 283. method
     with integer arguments starting at ‘0’).  If it does not support
     either of those protocols, *note TypeError: 2c3. is raised.  If the
     second argument, 'sentinel', is given, then the first argument must
     be a callable object.  The iterator created in this case will call
     'callable' with no arguments for each call to its *note __next__():
     1315. method; if the value returned is equal to 'sentinel', *note
     StopIteration: c1b. will be raised, otherwise the value will be
     returned.

     See also *note Iterator Types: 232f.

     One useful application of the second form of ‘iter()’ is to build a
     block-reader.  For example, reading fixed-width blocks from a
     binary database file until the end of file is reached:

          from functools import partial
          with open('mydata.db', 'rb') as f:
              for block in iter(partial(f.read, 64), b''):
                  process_block(block)

 -- Function: len (object, /)

     Return the length (the number of items) of an object.  The argument
     may be a sequence (such as a string, bytes, tuple, list, or range)
     or a collection (such as a dictionary, set, or frozen set).

     'CPython implementation detail:' ‘len’ raises *note OverflowError:
     888. on lengths larger than *note sys.maxsize: 120a, such as *note
     range(2 ** 100): 94d.

 -- Class: list (iterable=(), /)

     Rather than being a function, ‘list’ is actually a mutable sequence
     type, as documented in *note Lists: 1dd8. and *note Sequence Types
     — list, tuple, range: 1de4.

 -- Function: locals ()

     Return a mapping object representing the current local symbol
     table, with variable names as the keys, and their currently bound
     references as the values.

     At module scope, as well as when using *note exec(): 17f. or *note
     eval(): 180. with a single namespace, this function returns the
     same namespace as *note globals(): 19ae.

     At class scope, it returns the namespace that will be passed to the
     metaclass constructor.

     When using ‘exec()’ or ‘eval()’ with separate local and global
     arguments, it returns the local namespace passed in to the function
     call.

     In all of the above cases, each call to ‘locals()’ in a given frame
     of execution will return the 'same' mapping object.  Changes made
     through the mapping object returned from ‘locals()’ will be visible
     as assigned, reassigned, or deleted local variables, and assigning,
     reassigning, or deleting local variables will immediately affect
     the contents of the returned mapping object.

     In an *note optimized scope: 17e. (including functions, generators,
     and coroutines), each call to ‘locals()’ instead returns a fresh
     dictionary containing the current bindings of the function’s local
     variables and any nonlocal cell references.  In this case, name
     binding changes made via the returned dict are 'not' written back
     to the corresponding local variables or nonlocal cell references,
     and assigning, reassigning, or deleting local variables and
     nonlocal cell references does 'not' affect the contents of
     previously returned dictionaries.

     Calling ‘locals()’ as part of a comprehension in a function,
     generator, or coroutine is equivalent to calling it in the
     containing scope, except that the comprehension’s initialised
     iteration variables will be included.  In other scopes, it behaves
     as if the comprehension were running as a nested function.

     Calling ‘locals()’ as part of a generator expression is equivalent
     to calling it in a nested generator function.

     Changed in version 3.12: The behaviour of ‘locals()’ in a
     comprehension has been updated as described in PEP 709(2).

     Changed in version 3.13: As part of PEP 667(3), the semantics of
     mutating the mapping objects returned from this function are now
     defined.  The behavior in *note optimized scopes: 17e. is now as
     described above.  Aside from being defined, the behaviour in other
     scopes remains unchanged from previous versions.

 -- Function: map (function, iterable, *iterables)

     Return an iterator that applies 'function' to every item of
     'iterable', yielding the results.  If additional 'iterables'
     arguments are passed, 'function' must take that many arguments and
     is applied to the items from all iterables in parallel.  With
     multiple iterables, the iterator stops when the shortest iterable
     is exhausted.  For cases where the function inputs are already
     arranged into argument tuples, see *note itertools.starmap(): 1128.

 -- Function: max (iterable, /, *, key=None)

 -- Function: max (iterable, /, *, default, key=None)

 -- Function: max (arg1, arg2, /, *args, key=None)

     Return the largest item in an iterable or the largest of two or
     more arguments.

     If one positional argument is provided, it should be an *note
     iterable: 126d.  The largest item in the iterable is returned.  If
     two or more positional arguments are provided, the largest of the
     positional arguments is returned.

     There are two optional keyword-only arguments.  The 'key' argument
     specifies a one-argument ordering function like that used for *note
     list.sort(): bee.  The 'default' argument specifies an object to
     return if the provided iterable is empty.  If the iterable is empty
     and 'default' is not provided, a *note ValueError: 202. is raised.

     If multiple items are maximal, the function returns the first one
     encountered.  This is consistent with other sort-stability
     preserving tools such as ‘sorted(iterable, key=keyfunc,
     reverse=True)[0]’ and ‘heapq.nlargest(1, iterable, key=keyfunc)’.

     Changed in version 3.4: Added the 'default' keyword-only parameter.

     Changed in version 3.8: The 'key' can be ‘None’.

 -- Class: memoryview (object)

     Return a “memory view” object created from the given argument.  See
     *note Memory Views: 2330. for more information.

 -- Function: min (iterable, /, *, key=None)

 -- Function: min (iterable, /, *, default, key=None)

 -- Function: min (arg1, arg2, /, *args, key=None)

     Return the smallest item in an iterable or the smallest of two or
     more arguments.

     If one positional argument is provided, it should be an *note
     iterable: 126d.  The smallest item in the iterable is returned.  If
     two or more positional arguments are provided, the smallest of the
     positional arguments is returned.

     There are two optional keyword-only arguments.  The 'key' argument
     specifies a one-argument ordering function like that used for *note
     list.sort(): bee.  The 'default' argument specifies an object to
     return if the provided iterable is empty.  If the iterable is empty
     and 'default' is not provided, a *note ValueError: 202. is raised.

     If multiple items are minimal, the function returns the first one
     encountered.  This is consistent with other sort-stability
     preserving tools such as ‘sorted(iterable, key=keyfunc)[0]’ and
     ‘heapq.nsmallest(1, iterable, key=keyfunc)’.

     Changed in version 3.4: Added the 'default' keyword-only parameter.

     Changed in version 3.8: The 'key' can be ‘None’.

 -- Function: next (iterator, /)

 -- Function: next (iterator, default, /)

     Retrieve the next item from the *note iterator: 1ac. by calling its
     *note __next__(): 1315. method.  If 'default' is given, it is
     returned if the iterator is exhausted, otherwise *note
     StopIteration: c1b. is raised.

 -- Class: object

     This is the ultimate base class of all other classes.  It has
     methods that are common to all instances of Python classes.  When
     the constructor is called, it returns a new featureless object.
     The constructor does not accept any arguments.

          Note: ‘object’ instances do 'not' have *note __dict__: 55e.
          attributes, so you can’t assign arbitrary attributes to an
          instance of ‘object’.

 -- Function: oct (integer, /)

     Convert an integer number to an octal string prefixed with “0o”.
     The result is a valid Python expression.  If 'integer' is not a
     Python *note int: 257. object, it has to define an *note
     __index__(): 720. method that returns an integer.  For example:

          >>> oct(8)
          '0o10'
          >>> oct(-56)
          '-0o70'

     If you want to convert an integer number to an octal string either
     with the prefix “0o” or not, you can use either of the following
     ways.

          >>> '%#o' % 10, '%o' % 10
          ('0o12', '12')
          >>> format(10, '#o'), format(10, 'o')
          ('0o12', '12')
          >>> f'{10:#o}', f'{10:o}'
          ('0o12', '12')

     See also *note format(): 622. for more information.

 -- Function: open (file, mode='r', buffering=-1, encoding=None,
          errors=None, newline=None, closefd=True, opener=None)

     Open 'file' and return a corresponding *note file object: 1208.  If
     the file cannot be opened, an *note OSError: 41a. is raised.  See
     *note Reading and Writing Files: 1e1e. for more examples of how to
     use this function.

     'file' is a *note path-like object: 2a0. giving the pathname
     (absolute or relative to the current working directory) of the file
     to be opened or an integer file descriptor of the file to be
     wrapped.  (If a file descriptor is given, it is closed when the
     returned I/O object is closed unless 'closefd' is set to ‘False’.)

     'mode' is an optional string that specifies the mode in which the
     file is opened.  It defaults to ‘'r'’ which means open for reading
     in text mode.  Other common values are ‘'w'’ for writing
     (truncating the file if it already exists), ‘'x'’ for exclusive
     creation, and ‘'a'’ for appending (which on 'some' Unix systems,
     means that 'all' writes append to the end of the file regardless of
     the current seek position).  In text mode, if 'encoding' is not
     specified the encoding used is platform-dependent: *note
     locale.getencoding(): 2dc. is called to get the current locale
     encoding.  (For reading and writing raw bytes use binary mode and
     leave 'encoding' unspecified.)  The available modes are:

     Character     Meaning
                   
     ----------------------------------------------------------------------------------
                   
     ‘'r'’         open for reading (default)
                   
                   
     ‘'w'’         open for writing, truncating the file first
                   
                   
     ‘'x'’         open for exclusive creation, failing if the file already exists
                   
                   
     ‘'a'’         open for writing, appending to the end of file if it exists
                   
                   
     ‘'b'’         binary mode
                   
                   
     ‘'t'’         text mode (default)
                   
                   
     ‘'+'’         open for updating (reading and writing)
                   

     The default mode is ‘'r'’ (open for reading text, a synonym of
     ‘'rt'’).  Modes ‘'w+'’ and ‘'w+b'’ open and truncate the file.
     Modes ‘'r+'’ and ‘'r+b'’ open the file with no truncation.

     As mentioned in the *note Overview: 2332, Python distinguishes
     between binary and text I/O. Files opened in binary mode (including
     ‘'b'’ in the 'mode' argument) return contents as *note bytes: 1c2.
     objects without any decoding.  In text mode (the default, or when
     ‘'t'’ is included in the 'mode' argument), the contents of the file
     are returned as *note str: 44f, the bytes having been first decoded
     using a platform-dependent encoding or using the specified
     'encoding' if given.

          Note: Python doesn’t depend on the underlying operating
          system’s notion of text files; all the processing is done by
          Python itself, and is therefore platform-independent.

     'buffering' is an optional integer used to set the buffering
     policy.  Pass 0 to switch buffering off (only allowed in binary
     mode), 1 to select line buffering (only usable when writing in text
     mode), and an integer > 1 to indicate the size in bytes of a
     fixed-size chunk buffer.  Note that specifying a buffer size this
     way applies for binary buffered I/O, but ‘TextIOWrapper’ (i.e.,
     files opened with ‘mode='r+'’) would have another buffering.  To
     disable buffering in ‘TextIOWrapper’, consider using the
     ‘write_through’ flag for *note io.TextIOWrapper.reconfigure(): b64.
     When no 'buffering' argument is given, the default buffering policy
     works as follows:

        * Binary files are buffered in fixed-size chunks; the size of
          the buffer is chosen using a heuristic trying to determine the
          underlying device’s “block size” and falling back on *note
          io.DEFAULT_BUFFER_SIZE: 17d7.  On many systems, the buffer
          will typically be 4096 or 8192 bytes long.

        * “Interactive” text files (files for which *note isatty():
          1e21. returns ‘True’) use line buffering.  Other text files
          use the policy described above for binary files.

     'encoding' is the name of the encoding used to decode or encode the
     file.  This should only be used in text mode.  The default encoding
     is platform dependent (whatever *note locale.getencoding(): 2dc.
     returns), but any *note text encoding: 2333. supported by Python
     can be used.  See the *note codecs: 1b. module for the list of
     supported encodings.

     'errors' is an optional string that specifies how encoding and
     decoding errors are to be handled—this cannot be used in binary
     mode.  A variety of standard error handlers are available (listed
     under *note Error Handlers: 1915.), though any error handling name
     that has been registered with *note codecs.register_error(): 14ea.
     is also valid.  The standard names include:

        * ‘'strict'’ to raise a *note ValueError: 202. exception if
          there is an encoding error.  The default value of ‘None’ has
          the same effect.

        * ‘'ignore'’ ignores errors.  Note that ignoring encoding errors
          can lead to data loss.

        * ‘'replace'’ causes a replacement marker (such as ‘'?'’) to be
          inserted where there is malformed data.

        * ‘'surrogateescape'’ will represent any incorrect bytes as low
          surrogate code units ranging from U+DC80 to U+DCFF. These
          surrogate code units will then be turned back into the same
          bytes when the ‘surrogateescape’ error handler is used when
          writing data.  This is useful for processing files in an
          unknown encoding.

        * ‘'xmlcharrefreplace'’ is only supported when writing to a
          file.  Characters not supported by the encoding are replaced
          with the appropriate XML character reference ‘&#NNN;’.

        * ‘'backslashreplace'’ replaces malformed data by Python’s
          backslashed escape sequences.

        * ‘'namereplace'’ (also only supported when writing) replaces
          unsupported characters with ‘\N{...}’ escape sequences.

     'newline' determines how to parse newline characters from the
     stream.  It can be ‘None’, ‘''’, ‘'\n'’, ‘'\r'’, and ‘'\r\n'’.  It
     works as follows:

        * When reading input from the stream, if 'newline' is ‘None’,
          universal newlines mode is enabled.  Lines in the input can
          end in ‘'\n'’, ‘'\r'’, or ‘'\r\n'’, and these are translated
          into ‘'\n'’ before being returned to the caller.  If it is
          ‘''’, universal newlines mode is enabled, but line endings are
          returned to the caller untranslated.  If it has any of the
          other legal values, input lines are only terminated by the
          given string, and the line ending is returned to the caller
          untranslated.

        * When writing output to the stream, if 'newline' is ‘None’, any
          ‘'\n'’ characters written are translated to the system default
          line separator, *note os.linesep: 2334.  If 'newline' is ‘''’
          or ‘'\n'’, no translation takes place.  If 'newline' is any of
          the other legal values, any ‘'\n'’ characters written are
          translated to the given string.

     If 'closefd' is ‘False’ and a file descriptor rather than a
     filename was given, the underlying file descriptor will be kept
     open when the file is closed.  If a filename is given 'closefd'
     must be ‘True’ (the default); otherwise, an error will be raised.

     A custom opener can be used by passing a callable as 'opener'.  The
     underlying file descriptor for the file object is then obtained by
     calling 'opener' with ('file', 'flags').  'opener' must return an
     open file descriptor (passing *note os.open: dc0. as 'opener'
     results in functionality similar to passing ‘None’).

     The newly created file is *note non-inheritable: f30.

     The following example uses the *note dir_fd: 112e. parameter of the
     *note os.open(): dc0. function to open a file relative to a given
     directory:

          >>> import os
          >>> dir_fd = os.open('somedir', os.O_RDONLY)
          >>> def opener(path, flags):
          ...     return os.open(path, flags, dir_fd=dir_fd)
          ...
          >>> with open('spamspam.txt', 'w', opener=opener) as f:
          ...     print('This will be written to somedir/spamspam.txt', file=f)
          ...
          >>> os.close(dir_fd)  # don't leak a file descriptor

     The type of *note file object: 1208. returned by the ‘open()’
     function depends on the mode.  When ‘open()’ is used to open a file
     in a text mode (‘'w'’, ‘'r'’, ‘'wt'’, ‘'rt'’, etc.), it returns a
     subclass of *note io.TextIOBase: 698. (specifically *note
     io.TextIOWrapper: 7bf.).  When used to open a file in a binary mode
     with buffering, the returned class is a subclass of *note
     io.BufferedIOBase: 697.  The exact class varies: in read binary
     mode, it returns an *note io.BufferedReader: 1253.; in write binary
     and append binary modes, it returns an *note io.BufferedWriter:
     13fe, and in read/write mode, it returns an *note
     io.BufferedRandom: 13ff.  When buffering is disabled, the raw
     stream, a subclass of *note io.RawIOBase: 1114, *note io.FileIO:
     1359, is returned.

     See also the file handling modules, such as *note fileinput: 5b,
     *note io: 7f. (where ‘open()’ is declared), *note os: a1, *note
     os.path: a2, *note tempfile: e0, and *note shutil: c5.

     Raises an *note auditing event: 1a15. ‘open’ with arguments ‘path’,
     ‘mode’, ‘flags’.

     The ‘mode’ and ‘flags’ arguments may have been modified or inferred
     from the original call.

     Changed in version 3.3:

        * The 'opener' parameter was added.

        * The ‘'x'’ mode was added.

        * *note IOError: 1090. used to be raised, it is now an alias of
          *note OSError: 41a.

        * *note FileExistsError: 105b. is now raised if the file opened
          in exclusive creation mode (‘'x'’) already exists.

     Changed in version 3.4:

        * The file is now non-inheritable.

     Changed in version 3.5:

        * If the system call is interrupted and the signal handler does
          not raise an exception, the function now retries the system
          call instead of raising an *note InterruptedError: db6.
          exception (see PEP 475(4) for the rationale).

        * The ‘'namereplace'’ error handler was added.

     Changed in version 3.6:

        * Support added to accept objects implementing *note
          os.PathLike: c72.

        * On Windows, opening a console buffer may return a subclass of
          *note io.RawIOBase: 1114. other than *note io.FileIO: 1359.

     Changed in version 3.11: The ‘'U'’ mode has been removed.

 -- Function: ord (character, /)

     Return the ordinal value of a character.

     If the argument is a one-character string, return the Unicode code
     point of that character.  For example, ‘ord('a')’ returns the
     integer ‘97’ and ‘ord('€')’ (Euro sign) returns ‘8364’.  This is
     the inverse of *note chr(): 1785.

     If the argument is a *note bytes: 1c2. or *note bytearray: 2ea.
     object of length 1, return its single byte value.  For example,
     ‘ord(b'a')’ returns the integer ‘97’.

 -- Function: pow (base, exp, mod=None)

     Return 'base' to the power 'exp'; if 'mod' is present, return
     'base' to the power 'exp', modulo 'mod' (computed more efficiently
     than ‘pow(base, exp) % mod’).  The two-argument form ‘pow(base,
     exp)’ is equivalent to using the power operator: ‘base**exp’.

     When arguments are builtin numeric types with mixed operand types,
     the coercion rules for binary arithmetic operators apply.  For
     *note int: 257. operands, the result has the same type as the
     operands (after coercion) unless the second argument is negative;
     in that case, all arguments are converted to float and a float
     result is delivered.  For example, ‘pow(10, 2)’ returns ‘100’, but
     ‘pow(10, -2)’ returns ‘0.01’.  For a negative base of type ‘int’ or
     *note float: 2f7. and a non-integral exponent, a complex result is
     delivered.  For example, ‘pow(-9, 0.5)’ returns a value close to
     ‘3j’.  Whereas, for a negative base of type ‘int’ or ‘float’ with
     an integral exponent, a float result is delivered.  For example,
     ‘pow(-9, 2.0)’ returns ‘81.0’.

     For *note int: 257. operands 'base' and 'exp', if 'mod' is present,
     'mod' must also be of integer type and 'mod' must be nonzero.  If
     'mod' is present and 'exp' is negative, 'base' must be relatively
     prime to 'mod'.  In that case, ‘pow(inv_base, -exp, mod)’ is
     returned, where 'inv_base' is an inverse to 'base' modulo 'mod'.

     Here’s an example of computing an inverse for ‘38’ modulo ‘97’:

          >>> pow(38, -1, mod=97)
          23
          >>> 23 * 38 % 97 == 1
          True

     Changed in version 3.8: For *note int: 257. operands, the
     three-argument form of ‘pow’ now allows the second argument to be
     negative, permitting computation of modular inverses.

     Changed in version 3.8: Allow keyword arguments.  Formerly, only
     positional arguments were supported.

 -- Function: print (*objects, sep=' ', end='\n', file=None,
          flush=False)

     Print 'objects' to the text stream 'file', separated by 'sep' and
     followed by 'end'.  'sep', 'end', 'file', and 'flush', if present,
     must be given as keyword arguments.

     All non-keyword arguments are converted to strings like *note
     str(): 44f. does and written to the stream, separated by 'sep' and
     followed by 'end'.  Both 'sep' and 'end' must be strings; they can
     also be ‘None’, which means to use the default values.  If no
     'objects' are given, ‘print()’ will just write 'end'.

     The 'file' argument must be an object with a ‘write(string)’
     method; if it is not present or ‘None’, *note sys.stdout: aec. will
     be used.  Since printed arguments are converted to text strings,
     ‘print()’ cannot be used with binary mode file objects.  For these,
     use ‘file.write(...)’ instead.

     Output buffering is usually determined by 'file'.  However, if
     'flush' is true, the stream is forcibly flushed.

     Changed in version 3.3: Added the 'flush' keyword argument.

 -- Class: property (fget=None, fset=None, fdel=None, doc=None)

     Return a property attribute.

     'fget' is a function for getting an attribute value.  'fset' is a
     function for setting an attribute value.  'fdel' is a function for
     deleting an attribute value.  And 'doc' creates a docstring for the
     attribute.

     A typical use is to define a managed attribute ‘x’:

          class C:
              def __init__(self):
                  self._x = None

              def getx(self):
                  return self._x

              def setx(self, value):
                  self._x = value

              def delx(self):
                  del self._x

              x = property(getx, setx, delx, "I'm the 'x' property.")

     If 'c' is an instance of 'C', ‘c.x’ will invoke the getter, ‘c.x =
     value’ will invoke the setter, and ‘del c.x’ the deleter.

     If given, 'doc' will be the docstring of the property attribute.
     Otherwise, the property will copy 'fget'’s docstring (if it
     exists).  This makes it possible to create read-only properties
     easily using *note property(): 194. as a *note decorator: 734.:

          class Parrot:
              def __init__(self):
                  self._voltage = 100000

              @property
              def voltage(self):
                  """Get the current voltage."""
                  return self._voltage

     The ‘@property’ decorator turns the ‘voltage()’ method into a
     “getter” for a read-only attribute with the same name, and it sets
     the docstring for 'voltage' to “Get the current voltage.”

      -- Function: @getter

      -- Function: @setter

      -- Function: @deleter

          A property object has ‘getter’, ‘setter’, and ‘deleter’
          methods usable as decorators that create a copy of the
          property with the corresponding accessor function set to the
          decorated function.  This is best explained with an example:

               class C:
                   def __init__(self):
                       self._x = None

                   @property
                   def x(self):
                       """I'm the 'x' property."""
                       return self._x

                   @x.setter
                   def x(self, value):
                       self._x = value

                   @x.deleter
                   def x(self):
                       del self._x

          This code is exactly equivalent to the first example.  Be sure
          to give the additional functions the same name as the original
          property (‘x’ in this case.)

          The returned property object also has the attributes ‘fget’,
          ‘fset’, and ‘fdel’ corresponding to the constructor arguments.

     Changed in version 3.5: The docstrings of property objects are now
     writeable.

      -- Attribute: __name__

          Attribute holding the name of the property.  The name of the
          property can be changed at runtime.

          Added in version 3.13.

 -- Class: range (stop, /)

 -- Class: range (start, stop, step=1, /)

     Rather than being a function, ‘range’ is actually an immutable
     sequence type, as documented in *note Ranges: 2335. and *note
     Sequence Types — list, tuple, range: 1de4.

 -- Function: repr (object, /)

     Return a string containing a printable representation of an object.
     For many types, this function makes an attempt to return a string
     that would yield an object with the same value when passed to *note
     eval(): 180.; otherwise, the representation is a string enclosed in
     angle brackets that contains the name of the type of the object
     together with additional information often including the name and
     address of the object.  A class can control what this function
     returns for its instances by defining a *note __repr__(): 61f.
     method.  If *note sys.displayhook(): 156f. is not accessible, this
     function will raise *note RuntimeError: 195.

     This class has a custom representation that can be evaluated:

          class Person:
             def __init__(self, name, age):
                self.name = name
                self.age = age

             def __repr__(self):
                return f"Person('{self.name}', {self.age})"

 -- Function: reversed (object, /)

     Return a reverse *note iterator: 1ac.  The argument must be an
     object which has a *note __reversed__(): cad. method or supports
     the sequence protocol (the *note __len__(): 15da. method and the
     *note __getitem__(): 283. method with integer arguments starting at
     ‘0’).

 -- Function: round (number, ndigits=None)

     Return 'number' rounded to 'ndigits' precision after the decimal
     point.  If 'ndigits' is omitted or is ‘None’, it returns the
     nearest integer to its input.

     For the built-in types supporting ‘round()’, values are rounded to
     the closest multiple of 10 to the power minus 'ndigits'; if two
     multiples are equally close, rounding is done toward the even
     choice (so, for example, both ‘round(0.5)’ and ‘round(-0.5)’ are
     ‘0’, and ‘round(1.5)’ is ‘2’).  Any integer value is valid for
     'ndigits' (positive, zero, or negative).  The return value is an
     integer if 'ndigits' is omitted or ‘None’.  Otherwise, the return
     value has the same type as 'number'.

     For a general Python object ‘number’, ‘round’ delegates to
     ‘number.__round__’.

          Note: The behavior of ‘round()’ for floats can be surprising:
          for example, ‘round(2.675, 2)’ gives ‘2.67’ instead of the
          expected ‘2.68’.  This is not a bug: it’s a result of the fact
          that most decimal fractions can’t be represented exactly as a
          float.  See *note Floating-Point Arithmetic; Issues and
          Limitations: 1eb8. for more information.

 -- Class: set (iterable=(), /)

     Return a new ‘set’ object, optionally with elements taken from
     'iterable'.  ‘set’ is a built-in class.  See ‘set’ and *note Set
     Types — set, frozenset: 1de7. for documentation about this class.

     For other containers see the built-in *note frozenset: 5dd, *note
     list: 614, *note tuple: 373, and *note dict: 256. classes, as well
     as the *note collections: 1d. module.

 -- Function: setattr (object, name, value, /)

     This is the counterpart of *note getattr(): bf0.  The arguments are
     an object, a string, and an arbitrary value.  The string may name
     an existing attribute or a new attribute.  The function assigns the
     value to the attribute, provided the object allows it.  For
     example, ‘setattr(x, 'foobar', 123)’ is equivalent to ‘x.foobar =
     123’.

     'name' need not be a Python identifier as defined in *note
     Identifiers and keywords: 2040. unless the object chooses to
     enforce that, for example in a custom *note __getattribute__():
     bf1. or via *note __slots__: 153a.  An attribute whose name is not
     an identifier will not be accessible using the dot notation, but is
     accessible through *note getattr(): bf0. etc..

          Note: Since *note private name mangling: 1e5b. happens at
          compilation time, one must manually mangle a private
          attribute’s (attributes with two leading underscores) name in
          order to set it with ‘setattr()’.

 -- Class: slice (stop, /)

 -- Class: slice (start, stop, step=None, /)

     Return a *note slice: 2336. object representing the set of indices
     specified by ‘range(start, stop, step)’.  The 'start' and 'step'
     arguments default to ‘None’.

     Slice objects have read-only data attributes ‘start’, ‘stop’, and
     ‘step’ which merely return the argument values (or their default).
     They have no other explicit functionality; however, they are used
     by NumPy and other third-party packages.

      -- Attribute: start

      -- Attribute: stop

      -- Attribute: step

     Slice objects are also generated when extended indexing syntax is
     used.  For example: ‘a[start:stop:step]’ or ‘a[start:stop, i]’.
     See *note itertools.islice(): b67. for an alternate version that
     returns an *note iterator: 1ac.

     Changed in version 3.12: Slice objects are now *note hashable: 613.
     (provided *note start: 210b, *note stop: 210c, and *note step:
     210d. are hashable).

 -- Function: sorted (iterable, /, *, key=None, reverse=False)

     Return a new sorted list from the items in 'iterable'.

     Has two optional arguments which must be specified as keyword
     arguments.

     'key' specifies a function of one argument that is used to extract
     a comparison key from each element in 'iterable' (for example,
     ‘key=str.lower’).  The default value is ‘None’ (compare the
     elements directly).

     'reverse' is a boolean value.  If set to ‘True’, then the list
     elements are sorted as if each comparison were reversed.

     Use *note functools.cmp_to_key(): 121f. to convert an old-style
     'cmp' function to a 'key' function.

     The built-in ‘sorted()’ function is guaranteed to be stable.  A
     sort is stable if it guarantees not to change the relative order of
     elements that compare equal — this is helpful for sorting in
     multiple passes (for example, sort by department, then by salary
     grade).

     The sort algorithm uses only ‘<’ comparisons between items.  While
     defining an *note __lt__(): 12e7. method will suffice for sorting,
     PEP 8(5) recommends that all six *note rich comparisons: 2228. be
     implemented.  This will help avoid bugs when using the same data
     with other ordering tools such as *note max(): f40. that rely on a
     different underlying method.  Implementing all six comparisons also
     helps avoid confusion for mixed type comparisons which can call the
     reflected *note __gt__(): 1355. method.

     For sorting examples and a brief sorting tutorial, see *note
     Sorting Techniques: 2337.

 -- Function: @staticmethod

     Transform a method into a static method.

     A static method does not receive an implicit first argument.  To
     declare a static method, use this idiom:

          class C:
              @staticmethod
              def f(arg1, arg2, argN): ...

     The ‘@staticmethod’ form is a function *note decorator: 734. – see
     *note Function definitions: 1dce. for details.

     A static method can be called either on the class (such as ‘C.f()’)
     or on an instance (such as ‘C().f()’).  Moreover, the static method
     *note descriptor: 1677. is also callable, so it can be used in the
     class definition (such as ‘f()’).

     Static methods in Python are similar to those found in Java or C++.
     Also, see *note classmethod(): 166. for a variant that is useful
     for creating alternate class constructors.

     Like all decorators, it is also possible to call ‘staticmethod’ as
     a regular function and do something with its result.  This is
     needed in some cases where you need a reference to a function from
     a class body and you want to avoid the automatic transformation to
     instance method.  For these cases, use this idiom:

          def regular_function():
              ...

          class C:
              method = staticmethod(regular_function)

     For more information on static methods, see *note The standard type
     hierarchy: 2094.

     Changed in version 3.10: Static methods now inherit the method
     attributes (*note __module__: 20ad, *note __name__: 131c, *note
     __qualname__: 20ac, *note __doc__: 121e. and *note __annotations__:
     121d.), have a new ‘__wrapped__’ attribute, and are now callable as
     regular functions.

 -- Class: str (*, encoding='utf-8', errors='strict')

 -- Class: str (object)

 -- Class: str (object, encoding, errors='strict')

 -- Class: str (object, *, errors)

     Return a ‘str’ version of 'object'.  See *note str(): 44f. for
     details.

     ‘str’ is the built-in string *note class: 1aa4.  For general
     information about strings, see *note Text Sequence Type — str:
     1d92.

 -- Function: sum (iterable, /, start=0)

     Sums 'start' and the items of an 'iterable' from left to right and
     returns the total.  The 'iterable'’s items are normally numbers,
     and the start value is not allowed to be a string.

     For some use cases, there are good alternatives to ‘sum()’.  The
     preferred, fast way to concatenate a sequence of strings is by
     calling ‘''.join(sequence)’.  To add floating-point values with
     extended precision, see *note math.fsum(): 1422.  To concatenate a
     series of iterables, consider using *note itertools.chain(): 2338.

     Changed in version 3.8: The 'start' parameter can be specified as a
     keyword argument.

     Changed in version 3.12: Summation of floats switched to an
     algorithm that gives higher accuracy and better commutativity on
     most builds.

 -- Class: super

 -- Class: super (type, object_or_type=None, /)

     Return a proxy object that delegates method calls to a parent or
     sibling class of 'type'.  This is useful for accessing inherited
     methods that have been overridden in a class.

     The 'object_or_type' determines the *note method resolution order:
     2339. to be searched.  The search starts from the class right after
     the 'type'.

     For example, if *note __mro__: 20da. of 'object_or_type' is ‘D -> B
     -> C -> A -> object’ and the value of 'type' is ‘B’, then *note
     super(): 4de. searches ‘C -> A -> object’.

     The *note __mro__: 20da. attribute of the class corresponding to
     'object_or_type' lists the method resolution search order used by
     both *note getattr(): bf0. and *note super(): 4de.  The attribute
     is dynamic and can change whenever the inheritance hierarchy is
     updated.

     If the second argument is omitted, the super object returned is
     unbound.  If the second argument is an object, ‘isinstance(obj,
     type)’ must be true.  If the second argument is a type,
     ‘issubclass(type2, type)’ must be true (this is useful for
     classmethods).

     When called directly within an ordinary method of a class, both
     arguments may be omitted (“zero-argument ‘super()’”).  In this
     case, 'type' will be the enclosing class, and 'obj' will be the
     first argument of the immediately enclosing function (typically
     ‘self’).  (This means that zero-argument ‘super()’ will not work as
     expected within nested functions, including generator expressions,
     which implicitly create nested functions.)

     There are two typical use cases for 'super'.  In a class hierarchy
     with single inheritance, 'super' can be used to refer to parent
     classes without naming them explicitly, thus making the code more
     maintainable.  This use closely parallels the use of 'super' in
     other programming languages.

     The second use case is to support cooperative multiple inheritance
     in a dynamic execution environment.  This use case is unique to
     Python and is not found in statically compiled languages or
     languages that only support single inheritance.  This makes it
     possible to implement “diamond diagrams” where multiple base
     classes implement the same method.  Good design dictates that such
     implementations have the same calling signature in every case
     (because the order of calls is determined at runtime, because that
     order adapts to changes in the class hierarchy, and because that
     order can include sibling classes that are unknown prior to
     runtime).

     For both use cases, a typical superclass call looks like this:

          class C(B):
              def method(self, arg):
                  super().method(arg)    # This does the same thing as:
                                         # super(C, self).method(arg)

     In addition to method lookups, *note super(): 4de. also works for
     attribute lookups.  One possible use case for this is calling *note
     descriptors: 1677. in a parent or sibling class.

     Note that *note super(): 4de. is implemented as part of the binding
     process for explicit dotted attribute lookups such as
     ‘super().__getitem__(name)’.  It does so by implementing its own
     *note __getattribute__(): bf1. method for searching classes in a
     predictable order that supports cooperative multiple inheritance.
     Accordingly, ‘super()’ is undefined for implicit lookups using
     statements or operators such as ‘super()[name]’.

     Also note that, aside from the zero argument form, *note super():
     4de. is not limited to use inside methods.  The two argument form
     specifies the arguments exactly and makes the appropriate
     references.  The zero argument form only works inside a class
     definition, as the compiler fills in the necessary details to
     correctly retrieve the class being defined, as well as accessing
     the current instance for ordinary methods.

     For practical suggestions on how to design cooperative classes
     using *note super(): 4de, see guide to using super()(6).

 -- Class: tuple (iterable=(), /)

     Rather than being a function, ‘tuple’ is actually an immutable
     sequence type, as documented in *note Tuples: 22a3. and *note
     Sequence Types — list, tuple, range: 1de4.

 -- Class: type (object, /)

 -- Class: type (name, bases, dict, /, **kwargs)

     With one argument, return the type of an 'object'.  The return
     value is a type object and generally the same object as returned by
     *note object.__class__: 14fc.

     The *note isinstance(): 445. built-in function is recommended for
     testing the type of an object, because it takes subclasses into
     account.

     With three arguments, return a new type object.  This is
     essentially a dynamic form of the *note class: 131f. statement.
     The 'name' string is the class name and becomes the *note __name__:
     14fa. attribute.  The 'bases' tuple contains the base classes and
     becomes the *note __bases__: 14fb. attribute; if empty, *note
     object: a9b, the ultimate base of all classes, is added.  The
     'dict' dictionary contains attribute and method definitions for the
     class body; it may be copied or wrapped before becoming the *note
     __dict__: c7e. attribute.  The following two statements create
     identical ‘type’ objects:

          >>> class X:
          ...     a = 1
          ...
          >>> X = type('X', (), dict(a=1))

     See also:

        * *note Documentation on attributes and methods on classes:
          20d2.

        * *note Type Objects: 233a.

     Keyword arguments provided to the three argument form are passed to
     the appropriate metaclass machinery (usually *note
     __init_subclass__(): 634.) in the same way that keywords in a class
     definition (besides 'metaclass') would.

     See also *note Customizing class creation: c6c.

     Changed in version 3.6: Subclasses of ‘type’ which don’t override
     ‘type.__new__’ may no longer use the one-argument form to get the
     type of an object.

 -- Function: vars ()

 -- Function: vars (object, /)

     Return the *note __dict__: 55e. attribute for a module, class,
     instance, or any other object with a ‘__dict__’ attribute.

     Objects such as modules and instances have an updateable *note
     __dict__: 55e. attribute; however, other objects may have write
     restrictions on their ‘__dict__’ attributes (for example, classes
     use a *note types.MappingProxyType: 470. to prevent direct
     dictionary updates).

     Without an argument, ‘vars()’ acts like *note locals(): 141.

     A *note TypeError: 2c3. exception is raised if an object is
     specified but it doesn’t have a *note __dict__: 55e. attribute (for
     example, if its class defines the *note __slots__: 153a.
     attribute).

     Changed in version 3.13: The result of calling this function
     without an argument has been updated as described for the *note
     locals(): 141. builtin.

 -- Function: zip (*iterables, strict=False)

     Iterate over several iterables in parallel, producing tuples with
     an item from each one.

     Example:

          >>> for item in zip([1, 2, 3], ['sugar', 'spice', 'everything nice']):
          ...     print(item)
          ...
          (1, 'sugar')
          (2, 'spice')
          (3, 'everything nice')

     More formally: ‘zip()’ returns an iterator of tuples, where the
     'i'-th tuple contains the 'i'-th element from each of the argument
     iterables.

     Another way to think of ‘zip()’ is that it turns rows into columns,
     and columns into rows.  This is similar to transposing a matrix(7).

     ‘zip()’ is lazy: The elements won’t be processed until the iterable
     is iterated on, e.g.  by a ‘for’ loop or by wrapping in a *note
     list: 614.

     One thing to consider is that the iterables passed to ‘zip()’ could
     have different lengths; sometimes by design, and sometimes because
     of a bug in the code that prepared these iterables.  Python offers
     three different approaches to dealing with this issue:

        * By default, ‘zip()’ stops when the shortest iterable is
          exhausted.  It will ignore the remaining items in the longer
          iterables, cutting off the result to the length of the
          shortest iterable:

               >>> list(zip(range(3), ['fee', 'fi', 'fo', 'fum']))
               [(0, 'fee'), (1, 'fi'), (2, 'fo')]

        * ‘zip()’ is often used in cases where the iterables are assumed
          to be of equal length.  In such cases, it’s recommended to use
          the ‘strict=True’ option.  Its output is the same as regular
          ‘zip()’:

               >>> list(zip(('a', 'b', 'c'), (1, 2, 3), strict=True))
               [('a', 1), ('b', 2), ('c', 3)]

          Unlike the default behavior, it raises a *note ValueError:
          202. if one iterable is exhausted before the others:

               >>> for item in zip(range(3), ['fee', 'fi', 'fo', 'fum'], strict=True):
               ...     print(item)
               ...
               (0, 'fee')
               (1, 'fi')
               (2, 'fo')
               Traceback (most recent call last):
                 ...
               ValueError: zip() argument 2 is longer than argument 1

          Without the ‘strict=True’ argument, any bug that results in
          iterables of different lengths will be silenced, possibly
          manifesting as a hard-to-find bug in another part of the
          program.

        * Shorter iterables can be padded with a constant value to make
          all the iterables have the same length.  This is done by *note
          itertools.zip_longest(): 12e5.

     Edge cases: With a single iterable argument, ‘zip()’ returns an
     iterator of 1-tuples.  With no arguments, it returns an empty
     iterator.

     Tips and tricks:

        * The left-to-right evaluation order of the iterables is
          guaranteed.  This makes possible an idiom for clustering a
          data series into n-length groups using ‘zip(*[iter(s)]*n,
          strict=True)’.  This repeats the 'same' iterator ‘n’ times so
          that each output tuple has the result of ‘n’ calls to the
          iterator.  This has the effect of dividing the input into
          n-length chunks.

        * ‘zip()’ in conjunction with the ‘*’ operator can be used to
          unzip a list:

               >>> x = [1, 2, 3]
               >>> y = [4, 5, 6]
               >>> list(zip(x, y))
               [(1, 4), (2, 5), (3, 6)]
               >>> x2, y2 = zip(*zip(x, y))
               >>> x == list(x2) and y == list(y2)
               True

     Changed in version 3.10: Added the ‘strict’ argument.

 -- Function: __import__ (name, globals=None, locals=None, fromlist=(),
          level=0)

          Note: This is an advanced function that is not needed in
          everyday Python programming, unlike *note
          importlib.import_module(): 51b.

     This function is invoked by the *note import: 5e5. statement.  It
     can be replaced (by importing the *note builtins: 12. module and
     assigning to ‘builtins.__import__’) in order to change semantics of
     the ‘import’ statement, but doing so is 'strongly' discouraged as
     it is usually simpler to use import hooks (see PEP 302(8)) to
     attain the same goals and does not cause issues with code which
     assumes the default import implementation is in use.  Direct use of
     ‘__import__()’ is also discouraged in favor of *note
     importlib.import_module(): 51b.

     The function imports the module 'name', potentially using the given
     'globals' and 'locals' to determine how to interpret the name in a
     package context.  The 'fromlist' gives the names of objects or
     submodules that should be imported from the module given by 'name'.
     The standard implementation does not use its 'locals' argument at
     all and uses its 'globals' only to determine the package context of
     the *note import: 5e5. statement.

     'level' specifies whether to use absolute or relative imports.  ‘0’
     (the default) means only perform absolute imports.  Positive values
     for 'level' indicate the number of parent directories to search
     relative to the directory of the module calling ‘__import__()’ (see
     PEP 328(9) for the details).

     When the 'name' variable is of the form ‘package.module’, normally,
     the top-level package (the name up till the first dot) is returned,
     'not' the module named by 'name'.  However, when a non-empty
     'fromlist' argument is given, the module named by 'name' is
     returned.

     For example, the statement ‘import spam’ results in bytecode
     resembling the following code:

          spam = __import__('spam', globals(), locals(), [], 0)

     The statement ‘import spam.ham’ results in this call:

          spam = __import__('spam.ham', globals(), locals(), [], 0)

     Note how ‘__import__()’ returns the toplevel module here because
     this is the object that is bound to a name by the *note import:
     5e5. statement.

     On the other hand, the statement ‘from spam.ham import eggs,
     sausage as saus’ results in

          _temp = __import__('spam.ham', globals(), locals(), ['eggs', 'sausage'], 0)
          eggs = _temp.eggs
          saus = _temp.sausage

     Here, the ‘spam.ham’ module is returned from ‘__import__()’.  From
     this object, the names to import are retrieved and assigned to
     their respective names.

     If you simply want to import a module (potentially within a
     package) by name, use *note importlib.import_module(): 51b.

     Changed in version 3.3: Negative values for 'level' are no longer
     supported (which also changes the default value to 0).

     Changed in version 3.9: When the command line options *note -E:
     967. or *note -I: 968. are being used, the environment variable
     *note PYTHONCASEOK: 966. is now ignored.

   ---------- Footnotes ----------

   (1) Note that the parser only accepts the Unix-style end of line
convention.  If you are reading the code from a file, make sure to use
newline conversion mode to convert Windows or Mac-style newlines.

   (2) https://peps.python.org/pep-0709/

   (3) https://peps.python.org/pep-0667/

   (4) https://peps.python.org/pep-0475/

   (5) https://peps.python.org/pep-0008/

   (6) 
https://rhettinger.wordpress.com/2011/05/26/super-considered-super/

   (7) https://en.wikipedia.org/wiki/Transpose

   (8) https://peps.python.org/pep-0302/

   (9) https://peps.python.org/pep-0328/


File: python.info,  Node: Built-in Constants,  Next: Built-in Types,  Prev: Built-in Functions,  Up: The Python Standard Library

5.3 Built-in Constants
======================

A small number of constants live in the built-in namespace.  They are:

 -- Data: False

     The false value of the *note bool: 46b. type.  Assignments to
     ‘False’ are illegal and raise a *note SyntaxError: 18d.

 -- Data: True

     The true value of the *note bool: 46b. type.  Assignments to ‘True’
     are illegal and raise a *note SyntaxError: 18d.

 -- Data: None

     An object frequently used to represent the absence of a value, as
     when default arguments are not passed to a function.  Assignments
     to ‘None’ are illegal and raise a *note SyntaxError: 18d.  ‘None’
     is the sole instance of the *note NoneType: 858. type.

 -- Data: NotImplemented

     A special value which should be returned by the binary special
     methods (e.g.  *note __eq__(): b13, *note __lt__(): 12e7, *note
     __add__(): 2145, *note __rsub__(): 2155, etc.)  to indicate that
     the operation is not implemented with respect to the other type;
     may be returned by the in-place binary special methods (e.g.  *note
     __imul__(): 214a, *note __iand__(): 2164, etc.)  for the same
     purpose.  It should not be evaluated in a boolean context.
     ‘NotImplemented’ is the sole instance of the *note
     types.NotImplementedType: 859. type.

          Note: When a binary (or in-place) method returns
          ‘NotImplemented’ the interpreter will try the reflected
          operation on the other type (or some other fallback, depending
          on the operator).  If all attempts return ‘NotImplemented’,
          the interpreter will raise an appropriate exception.
          Incorrectly returning ‘NotImplemented’ will result in a
          misleading error message or the ‘NotImplemented’ value being
          returned to Python code.

          See *note Implementing the arithmetic operations: 2097. for
          examples.

          Caution: ‘NotImplemented’ and ‘NotImplementedError’ are not
          interchangeable.  This constant should only be used as
          described above; see *note NotImplementedError: 228. for
          details on correct usage of the exception.

     Changed in version 3.9: Evaluating ‘NotImplemented’ in a boolean
     context is deprecated.  While it currently evaluates as true, it
     will emit a *note DeprecationWarning: 1a5.  It will raise a *note
     TypeError: 2c3. in a future version of Python.

 -- Data: Ellipsis

     The same as the ellipsis literal “‘...’”, an object frequently used
     to indicate that something is omitted.  Assignment to ‘Ellipsis’ is
     possible, but assignment to ‘...’ raises a *note SyntaxError: 18d.
     ‘Ellipsis’ is the sole instance of the *note types.EllipsisType:
     857. type.

 -- Data: __debug__

     This constant is true if Python was not started with an *note -O:
     de3. option.  See also the *note assert: 972. statement.

     Note: The names *note None: 678, *note False: b4f, *note True: c2d.
     and *note __debug__: 7de. cannot be reassigned (assignments to
     them, even as an attribute name, raise *note SyntaxError: 18d.), so
     they can be considered “true” constants.

* Menu:

* Constants added by the site module::


File: python.info,  Node: Constants added by the site module,  Up: Built-in Constants

5.3.1 Constants added by the ‘site’ module
------------------------------------------

The *note site: c7. module (which is imported automatically during
startup, except if the *note -S: 11ec. command-line option is given)
adds several constants to the built-in namespace.  They are useful for
the interactive interpreter shell and should not be used in programs.

 -- Data: quit (code=None)
 -- Data: exit (code=None)

     Objects that when printed, print a message like “Use quit() or
     Ctrl-D (i.e.  EOF) to exit”, and when accessed directly in the
     interactive interpreter or called as functions, raise *note
     SystemExit: d69. with the specified exit code.

 -- Data: help

     Object that when printed, prints the message “Type help() for
     interactive help, or help(object) for help about object.”, and when
     accessed directly in the interactive interpreter, invokes the
     built-in help system (see *note help(): 8e0.).

 -- Data: copyright
 -- Data: credits

     Objects that when printed or called, print the text of copyright or
     credits, respectively.

 -- Data: license

     Object that when printed, prints the message “Type license() to see
     the full license text”, and when called, displays the full license
     text in a pager-like fashion (one screen at a time).


File: python.info,  Node: Built-in Types,  Next: Built-in Exceptions,  Prev: Built-in Constants,  Up: The Python Standard Library

5.4 Built-in Types
==================

The following sections describe the standard types that are built into
the interpreter.

The principal built-in types are numerics, sequences, mappings, classes,
instances and exceptions.

Some collection classes are mutable.  The methods that add, subtract, or
rearrange their members in place, and don’t return a specific item,
never return the collection instance itself but ‘None’.

Some operations are supported by several object types; in particular,
practically all objects can be compared for equality, tested for truth
value, and converted to a string (with the *note repr(): 803. function
or the slightly different *note str(): 44f. function).  The latter
function is implicitly used when an object is written by the *note
print(): fae. function.

* Menu:

* Truth Value Testing::
* Boolean Operations — and, or, not: Boolean Operations — and or not.
* Comparisons: Comparisons<2>.
* Numeric Types — int, float, complex: Numeric Types — int float complex.
* Boolean Type - bool::
* Iterator Types::
* Sequence Types — list, tuple, range: Sequence Types — list tuple range.
* Text Sequence Type — str::
* Binary Sequence Types — bytes, bytearray, memoryview: Binary Sequence Types — bytes bytearray memoryview.
* Set Types — set, frozenset: Set Types — set frozenset.
* Mapping Types — dict::
* Context Manager Types::
* Type Annotation Types — Generic Alias, Union: Type Annotation Types — Generic Alias Union.
* Other Built-in Types::
* Special Attributes::
* Integer string conversion length limitation::


File: python.info,  Node: Truth Value Testing,  Next: Boolean Operations — and or not,  Up: Built-in Types

5.4.1 Truth Value Testing
-------------------------

Any object can be tested for truth value, for use in an *note if: 2f3.
or *note while: 1d9a. condition or as operand of the Boolean operations
below.

By default, an object is considered true unless its class defines either
a *note __bool__(): 131d. method that returns ‘False’ or a *note
__len__(): 15da. method that returns zero, when called with the object.
(1)  Here are most of the built-in objects considered false:

   * constants defined to be false: ‘None’ and ‘False’

   * zero of any numeric type: ‘0’, ‘0.0’, ‘0j’, ‘Decimal(0)’,
     ‘Fraction(0, 1)’

   * empty sequences and collections: ‘''’, ‘()’, ‘[]’, ‘{}’, ‘set()’,
     ‘range(0)’

Operations and built-in functions that have a Boolean result always
return ‘0’ or ‘False’ for false and ‘1’ or ‘True’ for true, unless
otherwise stated.  (Important exception: the Boolean operations ‘or’ and
‘and’ always return one of their operands.)

   ---------- Footnotes ----------

   (1) Additional information on these special methods may be found in
the Python Reference Manual (*note Basic customization: 2113.).


File: python.info,  Node: Boolean Operations — and or not,  Next: Comparisons<2>,  Prev: Truth Value Testing,  Up: Built-in Types

5.4.2 Boolean Operations — ‘and’, ‘or’, ‘not’
---------------------------------------------

These are the Boolean operations, ordered by ascending priority:

Operation         Result                                Notes
                                                        
--------------------------------------------------------------------
                                                        
‘x or y’          if 'x' is true, then 'x', else 'y'    (1)
                                                        
                                                        
‘x and y’         if 'x' is false, then 'x', else 'y'   (2)
                                                        
                                                        
‘not x’           if 'x' is false, then ‘True’, else    (3)
                  ‘False’                               
                  

Notes:

  1. This is a short-circuit operator, so it only evaluates the second
     argument if the first one is false.

  2. This is a short-circuit operator, so it only evaluates the second
     argument if the first one is true.

  3. ‘not’ has a lower priority than non-Boolean operators, so ‘not a ==
     b’ is interpreted as ‘not (a == b)’, and ‘a == not b’ is a syntax
     error.


File: python.info,  Node: Comparisons<2>,  Next: Numeric Types — int float complex,  Prev: Boolean Operations — and or not,  Up: Built-in Types

5.4.3 Comparisons
-----------------

There are eight comparison operations in Python.  They all have the same
priority (which is higher than that of the Boolean operations).
Comparisons can be chained arbitrarily; for example, ‘x < y <= z’ is
equivalent to ‘x < y and y <= z’, except that 'y' is evaluated only once
(but in both cases 'z' is not evaluated at all when ‘x < y’ is found to
be false).

This table summarizes the comparison operations:

Operation        Meaning
                 
-----------------------------------------------
                 
‘<’              strictly less than
                 
                 
‘<=’             less than or equal
                 
                 
‘>’              strictly greater than
                 
                 
‘>=’             greater than or equal
                 
                 
‘==’             equal
                 
                 
‘!=’             not equal
                 
                 
‘is’             object identity
                 
                 
‘is not’         negated object identity
                 

Unless stated otherwise, objects of different types never compare equal.
The ‘==’ operator is always defined but for some object types (for
example, class objects) is equivalent to *note is: 2f5.  The ‘<’, ‘<=’,
‘>’ and ‘>=’ operators are only defined where they make sense; for
example, they raise a *note TypeError: 2c3. exception when one of the
arguments is a complex number.

Non-identical instances of a class normally compare as non-equal unless
the class defines the *note __eq__(): b13. method.

Instances of a class cannot be ordered with respect to other instances
of the same class, or other types of object, unless the class defines
enough of the methods *note __lt__(): 12e7, *note __le__(): 1354, *note
__gt__(): 1355, and *note __ge__(): 1356. (in general, ‘__lt__()’ and
*note __eq__(): b13. are sufficient, if you want the conventional
meanings of the comparison operators).

The behavior of the *note is: 2f5. and *note is not: 222f. operators
cannot be customized; also they can be applied to any two objects and
never raise an exception.

Two more operations with the same syntactic priority, *note in: 2f4. and
*note not in: 632, are supported by types that are *note iterable: 126d.
or implement the *note __contains__(): 1406. method.


File: python.info,  Node: Numeric Types — int float complex,  Next: Boolean Type - bool,  Prev: Comparisons<2>,  Up: Built-in Types

5.4.4 Numeric Types — ‘int’, ‘float’, ‘complex’
-----------------------------------------------

There are three distinct numeric types: 'integers', 'floating-point
numbers', and 'complex numbers'.  In addition, Booleans are a subtype of
integers.  Integers have unlimited precision.  Floating-point numbers
are usually implemented using double in C; information about the
precision and internal representation of floating-point numbers for the
machine on which your program is running is available in *note
sys.float_info: 1b7b.  Complex numbers have a real and imaginary part,
which are each a floating-point number.  To extract these parts from a
complex number 'z', use ‘z.real’ and ‘z.imag’.  (The standard library
includes the additional numeric types *note fractions.Fraction: 1e7, for
rationals, and *note decimal.Decimal: 29d, for floating-point numbers
with user-definable precision.)

Numbers are created by numeric literals or as the result of built-in
functions and operators.  Unadorned integer literals (including hex,
octal and binary numbers) yield integers.  Numeric literals containing a
decimal point or an exponent sign yield floating-point numbers.
Appending ‘'j'’ or ‘'J'’ to a numeric literal yields an imaginary number
(a complex number with a zero real part) which you can add to an integer
or float to get a complex number with real and imaginary parts.

Python fully supports mixed arithmetic: when a binary arithmetic
operator has operands of different numeric types, the operand with the
“narrower” type is widened to that of the other, where integer is
narrower than floating point, which is narrower than complex.  A
comparison between numbers of different types behaves as though the
exact values of those numbers were being compared.  (1)

The constructors *note int(): 257, *note float(): 2f7, and *note
complex(): 2f8. can be used to produce numbers of a specific type.

All numeric types (except complex) support the following operations (for
priorities of the operations, see *note Operator precedence: 2244.):

Operation                 Result                                Notes         Full documentation
                                                                              
-------------------------------------------------------------------------------------------------------
                                                                              
‘x + y’                   sum of 'x' and 'y'
                          
                                                                              
‘x - y’                   difference of 'x' and 'y'
                          
                                                                              
‘x * y’                   product of 'x' and 'y'
                          
                                                                              
‘x / y’                   quotient of 'x' and 'y'
                          
                                                                              
‘x // y’                  floored quotient of 'x' and 'y'       (1)(2)
                                                                
                                                                              
‘x % y’                   remainder of ‘x / y’                  (2)
                                                                
                                                                              
‘-x’                      'x' negated
                          
                                                                              
‘+x’                      'x' unchanged
                          
                                                                              
‘abs(x)’                  absolute value or magnitude of 'x'                  *note abs(): 1e45.
                                                                              
                                                                              
‘int(x)’                  'x' converted to integer              (3)(6)        *note int(): 257.
                                                                              
                                                                              
‘float(x)’                'x' converted to floating point       (4)(6)        *note float(): 2f7.
                                                                              
                                                                              
‘complex(re, im)’         a complex number with real part       (6)           *note complex(): 2f8.
                          're', imaginary part 'im'.  'im'                    
                          defaults to zero.
                          
                                                                              
‘c.conjugate()’           conjugate of the complex number 'c'
                          
                                                                              
‘divmod(x, y)’            the pair ‘(x // y, x % y)’            (2)           *note divmod(): 9ac.
                                                                              
                                                                              
‘pow(x, y)’               'x' to the power 'y'                  (5)           *note pow(): 9dd.
                                                                              
                                                                              
‘x ** y’                  'x' to the power 'y'                  (5)
                                                                

Notes:

  1. Also referred to as integer division.  For operands of type *note
     int: 257, the result has type ‘int’.  For operands of type *note
     float: 2f7, the result has type ‘float’.  In general, the result is
     a whole integer, though the result’s type is not necessarily ‘int’.
     The result is always rounded towards minus infinity: ‘1//2’ is ‘0’,
     ‘(-1)//2’ is ‘-1’, ‘1//(-2)’ is ‘-1’, and ‘(-1)//(-2)’ is ‘0’.

  2. Not for complex numbers.  Instead convert to floats using *note
     abs(): 1e45. if appropriate.

  3. 
     Conversion from *note float: 2f7. to *note int: 257. truncates,
     discarding the fractional part.  See functions *note math.floor():
     140a. and *note math.ceil(): 140b. for alternative conversions.

  4. float also accepts the strings “nan” and “inf” with an optional
     prefix “+” or “-” for Not a Number (NaN) and positive or negative
     infinity.

  5. Python defines ‘pow(0, 0)’ and ‘0 ** 0’ to be ‘1’, as is common for
     programming languages.

  6. The numeric literals accepted include the digits ‘0’ to ‘9’ or any
     Unicode equivalent (code points with the ‘Nd’ property).

     See the Unicode Standard(2) for a complete list of code points with
     the ‘Nd’ property.

All *note numbers.Real: 234e. types (*note int: 257. and *note float:
2f7.) also include the following operations:

Operation                Result
                         
---------------------------------------------------------------------------
                         
*note math.trunc(x): 140c.'x' truncated to *note Integral: 216f.
                         
                         
*note round(x[, n]): 1322.'x' rounded to 'n' digits, rounding half to
                         even.  If 'n' is omitted, it defaults to 0.
                         
                         
*note math.floor(x): 140a.the greatest *note Integral: 216f. <= 'x'
                         
                         
*note math.ceil(x): 140b.the least *note Integral: 216f. >= 'x'
                         

For additional numeric operations see the *note math: 8e. and *note
cmath: 18. modules.

* Menu:

* Bitwise Operations on Integer Types::
* Additional Methods on Integer Types::
* Additional Methods on Float::
* Hashing of numeric types::

   ---------- Footnotes ----------

   (1) As a consequence, the list ‘[1, 2]’ is considered equal to ‘[1.0,
2.0]’, and similarly for tuples.

   (2) 
https://unicode.org/Public/UNIDATA/extracted/DerivedNumericType.txt


File: python.info,  Node: Bitwise Operations on Integer Types,  Next: Additional Methods on Integer Types,  Up: Numeric Types — int float complex

5.4.4.1 Bitwise Operations on Integer Types
...........................................

Bitwise operations only make sense for integers.  The result of bitwise
operations is calculated as though carried out in two’s complement with
an infinite number of sign bits.

The priorities of the binary bitwise operations are all lower than the
numeric operations and higher than the comparisons; the unary operation
‘~’ has the same priority as the other unary numeric operations (‘+’ and
‘-’).

This table lists the bitwise operations sorted in ascending priority:

Operation        Result                               Notes
                                                      
---------------------------------------------------------------------
                                                      
‘x | y’          bitwise 'or' of 'x' and 'y'          (4)
                                                      
                                                      
‘x ^ y’          bitwise 'exclusive or' of 'x' and    (4)
                 'y'                                  
                 
                                                      
‘x & y’          bitwise 'and' of 'x' and 'y'         (4)
                                                      
                                                      
‘x << n’         'x' shifted left by 'n' bits         (1)(2)
                                                      
                                                      
‘x >> n’         'x' shifted right by 'n' bits        (1)(3)
                                                      
                                                      
‘~x’             the bits of 'x' inverted
                 

Notes:

  1. Negative shift counts are illegal and cause a *note ValueError:
     202. to be raised.

  2. A left shift by 'n' bits is equivalent to multiplication by ‘pow(2,
     n)’.

  3. A right shift by 'n' bits is equivalent to floor division by
     ‘pow(2, n)’.

  4. Performing these calculations with at least one extra sign
     extension bit in a finite two’s complement representation (a
     working bit-width of ‘1 + max(x.bit_length(), y.bit_length())’ or
     more) is sufficient to get the same result as if there were an
     infinite number of sign bits.


File: python.info,  Node: Additional Methods on Integer Types,  Next: Additional Methods on Float,  Prev: Bitwise Operations on Integer Types,  Up: Numeric Types — int float complex

5.4.4.2 Additional Methods on Integer Types
...........................................

The int type implements the *note numbers.Integral: 216f. *note abstract
base class: 11fa.  In addition, it provides a few more methods:

 -- Method: int.bit_length ()

     Return the number of bits necessary to represent an integer in
     binary, excluding the sign and leading zeros:

          >>> n = -37
          >>> bin(n)
          '-0b100101'
          >>> n.bit_length()
          6

     More precisely, if ‘x’ is nonzero, then ‘x.bit_length()’ is the
     unique positive integer ‘k’ such that ‘2**(k-1) <= abs(x) < 2**k’.
     Equivalently, when ‘abs(x)’ is small enough to have a correctly
     rounded logarithm, then ‘k = 1 + int(log(abs(x), 2))’.  If ‘x’ is
     zero, then ‘x.bit_length()’ returns ‘0’.

     Equivalent to:

          def bit_length(self):
              s = bin(self)       # binary representation:  bin(-37) --> '-0b100101'
              s = s.lstrip('-0b') # remove leading zeros and minus sign
              return len(s)       # len('100101') --> 6

     Added in version 3.1.

 -- Method: int.bit_count ()

     Return the number of ones in the binary representation of the
     absolute value of the integer.  This is also known as the
     population count.  Example:

          >>> n = 19
          >>> bin(n)
          '0b10011'
          >>> n.bit_count()
          3
          >>> (-n).bit_count()
          3

     Equivalent to:

          def bit_count(self):
              return bin(self).count("1")

     Added in version 3.10.

 -- Method: int.to_bytes (length=1, byteorder='big', *, signed=False)

     Return an array of bytes representing an integer.

          >>> (1024).to_bytes(2, byteorder='big')
          b'\x04\x00'
          >>> (1024).to_bytes(10, byteorder='big')
          b'\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00'
          >>> (-1024).to_bytes(10, byteorder='big', signed=True)
          b'\xff\xff\xff\xff\xff\xff\xff\xff\xfc\x00'
          >>> x = 1000
          >>> x.to_bytes((x.bit_length() + 7) // 8, byteorder='little')
          b'\xe8\x03'

     The integer is represented using 'length' bytes, and defaults to 1.
     An *note OverflowError: 888. is raised if the integer is not
     representable with the given number of bytes.

     The 'byteorder' argument determines the byte order used to
     represent the integer, and defaults to ‘"big"’.  If 'byteorder' is
     ‘"big"’, the most significant byte is at the beginning of the byte
     array.  If 'byteorder' is ‘"little"’, the most significant byte is
     at the end of the byte array.

     The 'signed' argument determines whether two’s complement is used
     to represent the integer.  If 'signed' is ‘False’ and a negative
     integer is given, an *note OverflowError: 888. is raised.  The
     default value for 'signed' is ‘False’.

     The default values can be used to conveniently turn an integer into
     a single byte object:

          >>> (65).to_bytes()
          b'A'

     However, when using the default arguments, don’t try to convert a
     value greater than 255 or you’ll get an *note OverflowError: 888.

     Equivalent to:

          def to_bytes(n, length=1, byteorder='big', signed=False):
              if byteorder == 'little':
                  order = range(length)
              elif byteorder == 'big':
                  order = reversed(range(length))
              else:
                  raise ValueError("byteorder must be either 'little' or 'big'")

              return bytes((n >> i*8) & 0xff for i in order)

     Added in version 3.2.

     Changed in version 3.11: Added default argument values for ‘length’
     and ‘byteorder’.

 -- Method: classmethod int.from_bytes (bytes, byteorder='big', *,
          signed=False)

     Return the integer represented by the given array of bytes.

          >>> int.from_bytes(b'\x00\x10', byteorder='big')
          16
          >>> int.from_bytes(b'\x00\x10', byteorder='little')
          4096
          >>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=True)
          -1024
          >>> int.from_bytes(b'\xfc\x00', byteorder='big', signed=False)
          64512
          >>> int.from_bytes([255, 0, 0], byteorder='big')
          16711680

     The argument 'bytes' must either be a *note bytes-like object: d55.
     or an iterable producing bytes.

     The 'byteorder' argument determines the byte order used to
     represent the integer, and defaults to ‘"big"’.  If 'byteorder' is
     ‘"big"’, the most significant byte is at the beginning of the byte
     array.  If 'byteorder' is ‘"little"’, the most significant byte is
     at the end of the byte array.  To request the native byte order of
     the host system, use *note sys.byteorder: 2353. as the byte order
     value.

     The 'signed' argument indicates whether two’s complement is used to
     represent the integer.

     Equivalent to:

          def from_bytes(bytes, byteorder='big', signed=False):
              if byteorder == 'little':
                  little_ordered = list(bytes)
              elif byteorder == 'big':
                  little_ordered = list(reversed(bytes))
              else:
                  raise ValueError("byteorder must be either 'little' or 'big'")

              n = sum(b << i*8 for i, b in enumerate(little_ordered))
              if signed and little_ordered and (little_ordered[-1] & 0x80):
                  n -= 1 << 8*len(little_ordered)

              return n

     Added in version 3.2.

     Changed in version 3.11: Added default argument value for
     ‘byteorder’.

 -- Method: int.as_integer_ratio ()

     Return a pair of integers whose ratio is equal to the original
     integer and has a positive denominator.  The integer ratio of
     integers (whole numbers) is always the integer as the numerator and
     ‘1’ as the denominator.

     Added in version 3.8.

 -- Method: int.is_integer ()

     Returns ‘True’.  Exists for duck type compatibility with *note
     float.is_integer(): 2354.

     Added in version 3.12.


File: python.info,  Node: Additional Methods on Float,  Next: Hashing of numeric types,  Prev: Additional Methods on Integer Types,  Up: Numeric Types — int float complex

5.4.4.3 Additional Methods on Float
...................................

The float type implements the *note numbers.Real: 234e. *note abstract
base class: 11fa.  float also has the following additional methods.

 -- Method: float.as_integer_ratio ()

     Return a pair of integers whose ratio is exactly equal to the
     original float.  The ratio is in lowest terms and has a positive
     denominator.  Raises *note OverflowError: 888. on infinities and a
     *note ValueError: 202. on NaNs.

 -- Method: float.is_integer ()

     Return ‘True’ if the float instance is finite with integral value,
     and ‘False’ otherwise:

          >>> (-2.0).is_integer()
          True
          >>> (3.2).is_integer()
          False

Two methods support conversion to and from hexadecimal strings.  Since
Python’s floats are stored internally as binary numbers, converting a
float to or from a 'decimal' string usually involves a small rounding
error.  In contrast, hexadecimal strings allow exact representation and
specification of floating-point numbers.  This can be useful when
debugging, and in numerical work.

 -- Method: float.hex ()

     Return a representation of a floating-point number as a hexadecimal
     string.  For finite floating-point numbers, this representation
     will always include a leading ‘0x’ and a trailing ‘p’ and exponent.

 -- Method: classmethod float.fromhex (s)

     Class method to return the float represented by a hexadecimal
     string 's'.  The string 's' may have leading and trailing
     whitespace.

Note that *note float.hex(): 1eba. is an instance method, while *note
float.fromhex(): 2356. is a class method.

A hexadecimal string takes the form:

     [sign] ['0x'] integer ['.' fraction] ['p' exponent]

where the optional ‘sign’ may by either ‘+’ or ‘-’, ‘integer’ and
‘fraction’ are strings of hexadecimal digits, and ‘exponent’ is a
decimal integer with an optional leading sign.  Case is not significant,
and there must be at least one hexadecimal digit in either the integer
or the fraction.  This syntax is similar to the syntax specified in
section 6.4.4.2 of the C99 standard, and also to the syntax used in Java
1.5 onwards.  In particular, the output of *note float.hex(): 1eba. is
usable as a hexadecimal floating-point literal in C or Java code, and
hexadecimal strings produced by C’s ‘%a’ format character or Java’s
‘Double.toHexString’ are accepted by *note float.fromhex(): 2356.

Note that the exponent is written in decimal rather than hexadecimal,
and that it gives the power of 2 by which to multiply the coefficient.
For example, the hexadecimal string ‘0x3.a7p10’ represents the
floating-point number ‘(3 + 10./16 + 7./16**2) * 2.0**10’, or ‘3740.0’:

     >>> float.fromhex('0x3.a7p10')
     3740.0

Applying the reverse conversion to ‘3740.0’ gives a different
hexadecimal string representing the same number:

     >>> float.hex(3740.0)
     '0x1.d380000000000p+11'


File: python.info,  Node: Hashing of numeric types,  Prev: Additional Methods on Float,  Up: Numeric Types — int float complex

5.4.4.4 Hashing of numeric types
................................

For numbers ‘x’ and ‘y’, possibly of different types, it’s a requirement
that ‘hash(x) == hash(y)’ whenever ‘x == y’ (see the *note __hash__():
b14. method documentation for more details).  For ease of implementation
and efficiency across a variety of numeric types (including *note int:
257, *note float: 2f7, *note decimal.Decimal: 29d. and *note
fractions.Fraction: 1e7.) Python’s hash for numeric types is based on a
single mathematical function that’s defined for any rational number, and
hence applies to all instances of ‘int’ and ‘fractions.Fraction’, and
all finite instances of ‘float’ and ‘decimal.Decimal’.  Essentially,
this function is given by reduction modulo ‘P’ for a fixed prime ‘P’.
The value of ‘P’ is made available to Python as the *note modulus: 2359.
attribute of *note sys.hash_info: 103a.

'CPython implementation detail:' Currently, the prime used is ‘P = 2**31
- 1’ on machines with 32-bit C longs and ‘P = 2**61 - 1’ on machines
with 64-bit C longs.

Here are the rules in detail:

   - If ‘x = m / n’ is a nonnegative rational number and ‘n’ is not
     divisible by ‘P’, define ‘hash(x)’ as ‘m * invmod(n, P) % P’, where
     ‘invmod(n, P)’ gives the inverse of ‘n’ modulo ‘P’.

   - If ‘x = m / n’ is a nonnegative rational number and ‘n’ is
     divisible by ‘P’ (but ‘m’ is not) then ‘n’ has no inverse modulo
     ‘P’ and the rule above doesn’t apply; in this case define ‘hash(x)’
     to be the constant value ‘sys.hash_info.inf’.

   - If ‘x = m / n’ is a negative rational number define ‘hash(x)’ as
     ‘-hash(-x)’.  If the resulting hash is ‘-1’, replace it with ‘-2’.

   - The particular values ‘sys.hash_info.inf’ and ‘-sys.hash_info.inf’
     are used as hash values for positive infinity or negative infinity
     (respectively).

   - For a *note complex: 2f8. number ‘z’, the hash values of the real
     and imaginary parts are combined by computing ‘hash(z.real) +
     sys.hash_info.imag * hash(z.imag)’, reduced modulo
     ‘2**sys.hash_info.width’ so that it lies in
     ‘range(-2**(sys.hash_info.width - 1), 2**(sys.hash_info.width -
     1))’.  Again, if the result is ‘-1’, it’s replaced with ‘-2’.

To clarify the above rules, here’s some example Python code, equivalent
to the built-in hash, for computing the hash of a rational number, *note
float: 2f7, or *note complex: 2f8.:

     import sys, math

     def hash_fraction(m, n):
         """Compute the hash of a rational number m / n.

         Assumes m and n are integers, with n positive.
         Equivalent to hash(fractions.Fraction(m, n)).

         """
         P = sys.hash_info.modulus
         # Remove common factors of P.  (Unnecessary if m and n already coprime.)
         while m % P == n % P == 0:
             m, n = m // P, n // P

         if n % P == 0:
             hash_value = sys.hash_info.inf
         else:
             # Fermat's Little Theorem: pow(n, P-1, P) is 1, so
             # pow(n, P-2, P) gives the inverse of n modulo P.
             hash_value = (abs(m) % P) * pow(n, P - 2, P) % P
         if m < 0:
             hash_value = -hash_value
         if hash_value == -1:
             hash_value = -2
         return hash_value

     def hash_float(x):
         """Compute the hash of a float x."""

         if math.isnan(x):
             return object.__hash__(x)
         elif math.isinf(x):
             return sys.hash_info.inf if x > 0 else -sys.hash_info.inf
         else:
             return hash_fraction(*x.as_integer_ratio())

     def hash_complex(z):
         """Compute the hash of a complex number z."""

         hash_value = hash_float(z.real) + sys.hash_info.imag * hash_float(z.imag)
         # do a signed reduction modulo 2**sys.hash_info.width
         M = 2**(sys.hash_info.width - 1)
         hash_value = (hash_value & (M - 1)) - (hash_value & M)
         if hash_value == -1:
             hash_value = -2
         return hash_value


File: python.info,  Node: Boolean Type - bool,  Next: Iterator Types,  Prev: Numeric Types — int float complex,  Up: Built-in Types

5.4.5 Boolean Type - ‘bool’
---------------------------

Booleans represent truth values.  The *note bool: 46b. type has exactly
two constant instances: ‘True’ and ‘False’.

The built-in function *note bool(): 46b. converts any value to a
boolean, if the value can be interpreted as a truth value (see section
*note Truth Value Testing: 164c. above).

For logical operations, use the *note boolean operators: 2349. ‘and’,
‘or’ and ‘not’.  When applying the bitwise operators ‘&’, ‘|’, ‘^’ to
two booleans, they return a bool equivalent to the logical operations
“and”, “or”, “xor”.  However, the logical operators ‘and’, ‘or’ and ‘!=’
should be preferred over ‘&’, ‘|’ and ‘^’.

Deprecated since version 3.12: The use of the bitwise inversion operator
‘~’ is deprecated and will raise an error in Python 3.16.

*note bool: 46b. is a subclass of *note int: 257. (see *note Numeric
Types — int, float, complex: 1d8d.).  In many numeric contexts, ‘False’
and ‘True’ behave like the integers 0 and 1, respectively.  However,
relying on this is discouraged; explicitly convert using *note int():
257. instead.


File: python.info,  Node: Iterator Types,  Next: Sequence Types — list tuple range,  Prev: Boolean Type - bool,  Up: Built-in Types

5.4.6 Iterator Types
--------------------

Python supports a concept of iteration over containers.  This is
implemented using two distinct methods; these are used to allow
user-defined classes to support iteration.  Sequences, described below
in more detail, always support the iteration methods.

One method needs to be defined for container objects to provide *note
iterable: 126d. support:

 -- Method: container.__iter__ ()

     Return an *note iterator: 1ac. object.  The object is required to
     support the iterator protocol described below.  If a container
     supports different types of iteration, additional methods can be
     provided to specifically request iterators for those iteration
     types.  (An example of an object supporting multiple forms of
     iteration would be a tree structure which supports both
     breadth-first and depth-first traversal.)  This method corresponds
     to the *note tp_iter: 153e. slot of the type structure for Python
     objects in the Python/C API.

The iterator objects themselves are required to support the following
two methods, which together form the 'iterator protocol':

 -- Method: iterator.__iter__ ()

     Return the *note iterator: 1ac. object itself.  This is required to
     allow both containers and iterators to be used with the *note for:
     2f2. and *note in: 2f4. statements.  This method corresponds to the
     *note tp_iter: 153e. slot of the type structure for Python objects
     in the Python/C API.

 -- Method: iterator.__next__ ()

     Return the next item from the *note iterator: 1ac.  If there are no
     further items, raise the *note StopIteration: c1b. exception.  This
     method corresponds to the *note tp_iternext: 153f. slot of the type
     structure for Python objects in the Python/C API.

Python defines several iterator objects to support iteration over
general and specific sequence types, dictionaries, and other more
specialized forms.  The specific types are not important beyond their
implementation of the iterator protocol.

Once an iterator’s *note __next__(): 1315. method raises *note
StopIteration: c1b, it must continue to do so on subsequent calls.
Implementations that do not obey this property are deemed broken.

* Menu:

* Generator Types::


File: python.info,  Node: Generator Types,  Up: Iterator Types

5.4.6.1 Generator Types
.......................

Python’s *note generator: 109f.s provide a convenient way to implement
the iterator protocol.  If a container object’s *note __iter__(): c90.
method is implemented as a generator, it will automatically return an
iterator object (technically, a generator object) supplying the *note
__iter__(): 1e65. and *note __next__(): 1e66. methods.  More information
about generators can be found in *note the documentation for the yield
expression: 21ef.


File: python.info,  Node: Sequence Types — list tuple range,  Next: Text Sequence Type — str,  Prev: Iterator Types,  Up: Built-in Types

5.4.7 Sequence Types — ‘list’, ‘tuple’, ‘range’
-----------------------------------------------

There are three basic sequence types: lists, tuples, and range objects.
Additional sequence types tailored for processing of *note binary data:
231c. and *note text strings: 1d92. are described in dedicated sections.

* Menu:

* Common Sequence Operations::
* Immutable Sequence Types::
* Mutable Sequence Types::
* Lists: Lists<2>.
* Tuples::
* Ranges::


File: python.info,  Node: Common Sequence Operations,  Next: Immutable Sequence Types,  Up: Sequence Types — list tuple range

5.4.7.1 Common Sequence Operations
..................................

The operations in the following table are supported by most sequence
types, both mutable and immutable.  The *note collections.abc.Sequence:
1209. ABC is provided to make it easier to correctly implement these
operations on custom sequence types.

This table lists the sequence operations sorted in ascending priority.
In the table, 's' and 't' are sequences of the same type, 'n', 'i', 'j'
and 'k' are integers and 'x' is an arbitrary object that meets any type
and value restrictions imposed by 's'.

The ‘in’ and ‘not in’ operations have the same priorities as the
comparison operations.  The ‘+’ (concatenation) and ‘*’ (repetition)
operations have the same priority as the corresponding numeric
operations.  (1)

Operation                      Result                               Notes
                                                                    
-----------------------------------------------------------------------------------
                                                                    
‘x in s’                       ‘True’ if an item of 's' is equal    (1)
                               to 'x', else ‘False’                 
                               
                                                                    
‘x not in s’                   ‘False’ if an item of 's' is equal   (1)
                               to 'x', else ‘True’                  
                               
                                                                    
‘s + t’                        the concatenation of 's' and 't'     (6)(7)
                                                                    
                                                                    
‘s * n’ or ‘n * s’             equivalent to adding 's' to itself   (2)(7)
                               'n' times                            
                               
                                                                    
‘s[i]’                         'i'th item of 's', origin 0          (3)(8)
                                                                    
                                                                    
‘s[i:j]’                       slice of 's' from 'i' to 'j'         (3)(4)
                                                                    
                                                                    
‘s[i:j:k]’                     slice of 's' from 'i' to 'j' with    (3)(5)
                               step 'k'                             
                               
                                                                    
‘len(s)’                       length of 's'
                               
                                                                    
‘min(s)’                       smallest item of 's'
                               
                                                                    
‘max(s)’                       largest item of 's'
                               

Sequences of the same type also support comparisons.  In particular,
tuples and lists are compared lexicographically by comparing
corresponding elements.  This means that to compare equal, every element
must compare equal and the two sequences must be of the same type and
have the same length.  (For full details see *note Comparisons: 2228. in
the language reference.)

Forward and reversed iterators over mutable sequences access values
using an index.  That index will continue to march forward (or backward)
even if the underlying sequence is mutated.  The iterator terminates
only when an *note IndexError: 1585. or a *note StopIteration: c1b. is
encountered (or when the index drops below zero).

Notes:

  1. While the ‘in’ and ‘not in’ operations are used only for simple
     containment testing in the general case, some specialised sequences
     (such as *note str: 44f, *note bytes: 1c2. and *note bytearray:
     2ea.) also use them for subsequence testing:

          >>> "gg" in "eggs"
          True

  2. Values of 'n' less than ‘0’ are treated as ‘0’ (which yields an
     empty sequence of the same type as 's').  Note that items in the
     sequence 's' are not copied; they are referenced multiple times.
     This often haunts new Python programmers; consider:

          >>> lists = [[]] * 3
          >>> lists
          [[], [], []]
          >>> lists[0].append(3)
          >>> lists
          [[3], [3], [3]]

     What has happened is that ‘[[]]’ is a one-element list containing
     an empty list, so all three elements of ‘[[]] * 3’ are references
     to this single empty list.  Modifying any of the elements of
     ‘lists’ modifies this single list.  You can create a list of
     different lists this way:

          >>> lists = [[] for i in range(3)]
          >>> lists[0].append(3)
          >>> lists[1].append(5)
          >>> lists[2].append(7)
          >>> lists
          [[3], [5], [7]]

     Further explanation is available in the FAQ entry *note How do I
     create a multidimensional list?: 2362.

  3. If 'i' or 'j' is negative, the index is relative to the end of
     sequence 's': ‘len(s) + i’ or ‘len(s) + j’ is substituted.  But
     note that ‘-0’ is still ‘0’.

  4. The slice of 's' from 'i' to 'j' is defined as the sequence of
     items with index 'k' such that ‘i <= k < j’.

        * If 'i' is omitted or ‘None’, use ‘0’.

        * If 'j' is omitted or ‘None’, use ‘len(s)’.

        * If 'i' or 'j' is less than ‘-len(s)’, use ‘0’.

        * If 'i' or 'j' is greater than ‘len(s)’, use ‘len(s)’.

        * If 'i' is greater than or equal to 'j', the slice is empty.

  5. The slice of 's' from 'i' to 'j' with step 'k' is defined as the
     sequence of items with index ‘x = i + n*k’ such that ‘0 <= n <
     (j-i)/k’.  In other words, the indices are ‘i’, ‘i+k’, ‘i+2*k’,
     ‘i+3*k’ and so on, stopping when 'j' is reached (but never
     including 'j').  When 'k' is positive, 'i' and 'j' are reduced to
     ‘len(s)’ if they are greater.  When 'k' is negative, 'i' and 'j'
     are reduced to ‘len(s) - 1’ if they are greater.  If 'i' or 'j' are
     omitted or ‘None’, they become “end” values (which end depends on
     the sign of 'k').  Note, 'k' cannot be zero.  If 'k' is ‘None’, it
     is treated like ‘1’.

  6. Concatenating immutable sequences always results in a new object.
     This means that building up a sequence by repeated concatenation
     will have a quadratic runtime cost in the total sequence length.
     To get a linear runtime cost, you must switch to one of the
     alternatives below:

        * if concatenating *note str: 44f. objects, you can build a list
          and use *note str.join(): 2363. at the end or else write to an
          *note io.StringIO: f5e. instance and retrieve its value when
          complete

        * if concatenating *note bytes: 1c2. objects, you can similarly
          use *note bytes.join(): 2364. or *note io.BytesIO: ed8, or you
          can do in-place concatenation with a *note bytearray: 2ea.
          object.  ‘bytearray’ objects are mutable and have an efficient
          overallocation mechanism

        * if concatenating *note tuple: 373. objects, extend a *note
          list: 614. instead

        * for other types, investigate the relevant class documentation

  7. Some sequence types (such as *note range: 94d.) only support item
     sequences that follow specific patterns, and hence don’t support
     sequence concatenation or repetition.

  8. An *note IndexError: 1585. is raised if 'i' is outside the sequence
     range.

Sequence Methods
................

Sequence types also support the following methods:

 -- Method: sequence.count (value, /)

     Return the total number of occurrences of 'value' in 'sequence'.

 -- Method: sequence.index (value[, start[, stop]])

     Return the index of the first occurrence of 'value' in 'sequence'.

     Raises *note ValueError: 202. if 'value' is not found in
     'sequence'.

     The 'start' or 'stop' arguments allow for efficient searching of
     subsections of the sequence, beginning at 'start' and ending at
     'stop'.  This is roughly equivalent to ‘start +
     sequence[start:stop].index(value)’, only without copying any data.

          Caution: Not all sequence types support passing the 'start'
          and 'stop' arguments.

   ---------- Footnotes ----------

   (1) They must have since the parser can’t tell the type of the
operands.


File: python.info,  Node: Immutable Sequence Types,  Next: Mutable Sequence Types,  Prev: Common Sequence Operations,  Up: Sequence Types — list tuple range

5.4.7.2 Immutable Sequence Types
................................

The only operation that immutable sequence types generally implement
that is not also implemented by mutable sequence types is support for
the *note hash(): 5ee. built-in.

This support allows immutable sequences, such as *note tuple: 373.
instances, to be used as *note dict: 256. keys and stored in *note set:
5dc. and *note frozenset: 5dd. instances.

Attempting to hash an immutable sequence that contains unhashable values
will result in *note TypeError: 2c3.


File: python.info,  Node: Mutable Sequence Types,  Next: Lists<2>,  Prev: Immutable Sequence Types,  Up: Sequence Types — list tuple range

5.4.7.3 Mutable Sequence Types
..............................

The operations in the following table are defined on mutable sequence
types.  The *note collections.abc.MutableSequence: 1a1. ABC is provided
to make it easier to correctly implement these operations on custom
sequence types.

In the table 's' is an instance of a mutable sequence type, 't' is any
iterable object and 'x' is an arbitrary object that meets any type and
value restrictions imposed by 's' (for example, *note bytearray: 2ea.
only accepts integers that meet the value restriction ‘0 <= x <= 255’).

Operation                          Result                               Notes
                                                                        
--------------------------------------------------------------------------------------------------
                                                                        
‘s[i] = x’                         item 'i' of 's' is replaced by 'x'
                                   
                                                                        
‘del s[i]’                         removes item 'i' of 's'
                                   
                                                                        
‘s[i:j] = t’                       slice of 's' from 'i' to 'j' is
                                   replaced by the contents of the
                                   iterable 't'
                                   
                                                                        
‘del s[i:j]’                       removes the elements of ‘s[i:j]’
                                   from the list (same as ‘s[i:j] =
                                   []’)
                                   
                                                                        
‘s[i:j:k] = t’                     the elements of ‘s[i:j:k]’ are       (1)
                                   replaced by those of 't'             
                                   
                                                                        
‘del s[i:j:k]’                     removes the elements of ‘s[i:j:k]’
                                   from the list
                                   
                                                                        
‘s += t’                           extends 's' with the contents of
                                   't' (for the most part the same as
                                   ‘s[len(s):len(s)] = t’)
                                   
                                                                        
‘s *= n’                           updates 's' with its contents        (2)
                                   repeated 'n' times                   
                                   

Notes:

  1. If 'k' is not equal to ‘1’, 't' must have the same length as the
     slice it is replacing.

  2. The value 'n' is an integer, or an object implementing *note
     __index__(): 720.  Zero and negative values of 'n' clear the
     sequence.  Items in the sequence are not copied; they are
     referenced multiple times, as explained for ‘s * n’ under *note
     Common Sequence Operations: 2361.

Mutable Sequence Methods
........................

Mutable sequence types also support the following methods:

 -- Method: sequence.append (value, /)

     Append 'value' to the end of the sequence.  This is equivalent to
     writing ‘seq[len(seq):len(seq)] = [value]’.

 -- Method: sequence.clear ()

     Added in version 3.3.

     Remove all items from 'sequence'.  This is equivalent to writing
     ‘del sequence[:]’.

 -- Method: sequence.copy ()

     Added in version 3.3.

     Create a shallow copy of 'sequence'.  This is equivalent to writing
     ‘sequence[:]’.

          Hint: The ‘copy()’ method is not part of the *note
          MutableSequence: 1a1. *note ABC: f4e, but most concrete
          mutable sequence types provide it.

 -- Method: sequence.extend (iterable, /)

     Extend 'sequence' with the contents of 'iterable'.  For the most
     part, this is the same as writing ‘seq[len(seq):len(seq)] =
     iterable’.

 -- Method: sequence.insert (index, value, /)

     Insert 'value' into 'sequence' at the given 'index'.  This is
     equivalent to writing ‘sequence[index:index] = [value]’.

 -- Method: sequence.pop (index=-1, /)

     Retrieve the item at 'index' and also removes it from 'sequence'.
     By default, the last item in 'sequence' is removed and returned.

 -- Method: sequence.remove (value, /)

     Remove the first item from 'sequence' where ‘sequence[i] == value’.

     Raises *note ValueError: 202. if 'value' is not found in
     'sequence'.

 -- Method: sequence.reverse ()

     Reverse the items of 'sequence' in place.  This method maintains
     economy of space when reversing a large sequence.  To remind users
     that it operates by side-effect, it returns ‘None’.


File: python.info,  Node: Lists<2>,  Next: Tuples,  Prev: Mutable Sequence Types,  Up: Sequence Types — list tuple range

5.4.7.4 Lists
.............

Lists are mutable sequences, typically used to store collections of
homogeneous items (where the precise degree of similarity will vary by
application).

 -- Class: list (iterable=(), /)

     Lists may be constructed in several ways:

        * Using a pair of square brackets to denote the empty list: ‘[]’

        * Using square brackets, separating items with commas: ‘[a]’,
          ‘[a, b, c]’

        * Using a list comprehension: ‘[x for x in iterable]’

        * Using the type constructor: ‘list()’ or ‘list(iterable)’

     The constructor builds a list whose items are the same and in the
     same order as 'iterable'’s items.  'iterable' may be either a
     sequence, a container that supports iteration, or an iterator
     object.  If 'iterable' is already a list, a copy is made and
     returned, similar to ‘iterable[:]’.  For example, ‘list('abc')’
     returns ‘['a', 'b', 'c']’ and ‘list( (1, 2, 3) )’ returns ‘[1, 2,
     3]’.  If no argument is given, the constructor creates a new empty
     list, ‘[]’.

     Many other operations also produce lists, including the *note
     sorted(): bed. built-in.

     Lists implement all of the *note common: 2361. and *note mutable:
     231a. sequence operations.  Lists also provide the following
     additional method:

      -- Method: sort (*, key=None, reverse=False)

          This method sorts the list in place, using only ‘<’
          comparisons between items.  Exceptions are not suppressed - if
          any comparison operations fail, the entire sort operation will
          fail (and the list will likely be left in a partially modified
          state).

          ‘sort()’ accepts two arguments that can only be passed by
          keyword (*note keyword-only arguments: 2a5.):

          'key' specifies a function of one argument that is used to
          extract a comparison key from each list element (for example,
          ‘key=str.lower’).  The key corresponding to each item in the
          list is calculated once and then used for the entire sorting
          process.  The default value of ‘None’ means that list items
          are sorted directly without calculating a separate key value.

          The *note functools.cmp_to_key(): 121f. utility is available
          to convert a 2.x style 'cmp' function to a 'key' function.

          'reverse' is a boolean value.  If set to ‘True’, then the list
          elements are sorted as if each comparison were reversed.

          This method modifies the sequence in place for economy of
          space when sorting a large sequence.  To remind users that it
          operates by side effect, it does not return the sorted
          sequence (use *note sorted(): bed. to explicitly request a new
          sorted list instance).

          The ‘sort()’ method is guaranteed to be stable.  A sort is
          stable if it guarantees not to change the relative order of
          elements that compare equal — this is helpful for sorting in
          multiple passes (for example, sort by department, then by
          salary grade).

          For sorting examples and a brief sorting tutorial, see *note
          Sorting Techniques: 2337.

          'CPython implementation detail:' While a list is being sorted,
          the effect of attempting to mutate, or even inspect, the list
          is undefined.  The C implementation of Python makes the list
          appear empty for the duration, and raises *note ValueError:
          202. if it can detect that the list has been mutated during a
          sort.


File: python.info,  Node: Tuples,  Next: Ranges,  Prev: Lists<2>,  Up: Sequence Types — list tuple range

5.4.7.5 Tuples
..............

Tuples are immutable sequences, typically used to store collections of
heterogeneous data (such as the 2-tuples produced by the *note
enumerate(): 14d0. built-in).  Tuples are also used for cases where an
immutable sequence of homogeneous data is needed (such as allowing
storage in a *note set: 5dc. or *note dict: 256. instance).

 -- Class: tuple (iterable=(), /)

     Tuples may be constructed in a number of ways:

        * Using a pair of parentheses to denote the empty tuple: ‘()’

        * Using a trailing comma for a singleton tuple: ‘a,’ or ‘(a,)’

        * Separating items with commas: ‘a, b, c’ or ‘(a, b, c)’

        * Using the *note tuple(): 373. built-in: ‘tuple()’ or
          ‘tuple(iterable)’

     The constructor builds a tuple whose items are the same and in the
     same order as 'iterable'’s items.  'iterable' may be either a
     sequence, a container that supports iteration, or an iterator
     object.  If 'iterable' is already a tuple, it is returned
     unchanged.  For example, ‘tuple('abc')’ returns ‘('a', 'b', 'c')’
     and ‘tuple( [1, 2, 3] )’ returns ‘(1, 2, 3)’.  If no argument is
     given, the constructor creates a new empty tuple, ‘()’.

     Note that it is actually the comma which makes a tuple, not the
     parentheses.  The parentheses are optional, except in the empty
     tuple case, or when they are needed to avoid syntactic ambiguity.
     For example, ‘f(a, b, c)’ is a function call with three arguments,
     while ‘f((a, b, c))’ is a function call with a 3-tuple as the sole
     argument.

     Tuples implement all of the *note common: 2361. sequence
     operations.

For heterogeneous collections of data where access by name is clearer
than access by index, *note collections.namedtuple(): 1ca. may be a more
appropriate choice than a simple tuple object.


File: python.info,  Node: Ranges,  Prev: Tuples,  Up: Sequence Types — list tuple range

5.4.7.6 Ranges
..............

The *note range: 94d. type represents an immutable sequence of numbers
and is commonly used for looping a specific number of times in *note
for: 2f2. loops.

 -- Class: range (stop, /)

 -- Class: range (start, stop, step=1, /)

     The arguments to the range constructor must be integers (either
     built-in *note int: 257. or any object that implements the *note
     __index__(): 720. special method).  If the 'step' argument is
     omitted, it defaults to ‘1’.  If the 'start' argument is omitted,
     it defaults to ‘0’.  If 'step' is zero, *note ValueError: 202. is
     raised.

     For a positive 'step', the contents of a range ‘r’ are determined
     by the formula ‘r[i] = start + step*i’ where ‘i >= 0’ and ‘r[i] <
     stop’.

     For a negative 'step', the contents of the range are still
     determined by the formula ‘r[i] = start + step*i’, but the
     constraints are ‘i >= 0’ and ‘r[i] > stop’.

     A range object will be empty if ‘r[0]’ does not meet the value
     constraint.  Ranges do support negative indices, but these are
     interpreted as indexing from the end of the sequence determined by
     the positive indices.

     Ranges containing absolute values larger than *note sys.maxsize:
     120a. are permitted but some features (such as *note len(): 631.)
     may raise *note OverflowError: 888.

     Range examples:

          >>> list(range(10))
          [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
          >>> list(range(1, 11))
          [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
          >>> list(range(0, 30, 5))
          [0, 5, 10, 15, 20, 25]
          >>> list(range(0, 10, 3))
          [0, 3, 6, 9]
          >>> list(range(0, -10, -1))
          [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
          >>> list(range(0))
          []
          >>> list(range(1, 0))
          []

     Ranges implement all of the *note common: 2361. sequence operations
     except concatenation and repetition (due to the fact that range
     objects can only represent sequences that follow a strict pattern
     and repetition and concatenation will usually violate that
     pattern).

      -- Attribute: start

          The value of the 'start' parameter (or ‘0’ if the parameter
          was not supplied)

      -- Attribute: stop

          The value of the 'stop' parameter

      -- Attribute: step

          The value of the 'step' parameter (or ‘1’ if the parameter was
          not supplied)

The advantage of the *note range: 94d. type over a regular *note list:
614. or *note tuple: 373. is that a ‘range’ object will always take the
same (small) amount of memory, no matter the size of the range it
represents (as it only stores the ‘start’, ‘stop’ and ‘step’ values,
calculating individual items and subranges as needed).

Range objects implement the *note collections.abc.Sequence: 1209. ABC,
and provide features such as containment tests, element index lookup,
slicing and support for negative indices (see *note Sequence Types —
list, tuple, range: 1de4.):

     >>> r = range(0, 20, 2)
     >>> r
     range(0, 20, 2)
     >>> 11 in r
     False
     >>> 10 in r
     True
     >>> r.index(10)
     5
     >>> r[5]
     10
     >>> r[:5]
     range(0, 10, 2)
     >>> r[-1]
     18

Testing range objects for equality with ‘==’ and ‘!=’ compares them as
sequences.  That is, two range objects are considered equal if they
represent the same sequence of values.  (Note that two range objects
that compare equal might have different *note start: 2370, *note stop:
2371. and *note step: 2372. attributes, for example ‘range(0) ==
range(2, 1, 3)’ or ‘range(0, 3, 2) == range(0, 4, 2)’.)

Changed in version 3.2: Implement the Sequence ABC. Support slicing and
negative indices.  Test *note int: 257. objects for membership in
constant time instead of iterating through all items.

Changed in version 3.3: Define ‘==’ and ‘!=’ to compare range objects
based on the sequence of values they define (instead of comparing based
on object identity).

Added the *note start: 2370, *note stop: 2371. and *note step: 2372.
attributes.

See also
........

   * The linspace recipe(1) shows how to implement a lazy version of
     range suitable for floating-point applications.

   ---------- Footnotes ----------

   (1) 
https://code.activestate.com/recipes/579000-equally-spaced-numbers-linspace/


File: python.info,  Node: Text Sequence Type — str,  Next: Binary Sequence Types — bytes bytearray memoryview,  Prev: Sequence Types — list tuple range,  Up: Built-in Types

5.4.8 Text Sequence Type — ‘str’
--------------------------------

Textual data in Python is handled with *note str: 44f. objects, or
'strings'.  Strings are immutable *note sequences: 1de4. of Unicode code
points.  String literals are written in a variety of ways:

   * Single quotes: ‘'allows embedded "double" quotes'’

   * Double quotes: ‘"allows embedded 'single' quotes"’

   * Triple quoted: ‘'''Three single quotes'''’, ‘"""Three double
     quotes"""’

Triple quoted strings may span multiple lines - all associated
whitespace will be included in the string literal.

String literals that are part of a single expression and have only
whitespace between them will be implicitly converted to a single string
literal.  That is, ‘("spam " "eggs") == "spam eggs"’.

See *note String and Bytes literals: 2050. for more about the various
forms of string literal, including supported *note escape sequences:
45d, and the ‘r’ (“raw”) prefix that disables most escape sequence
processing.

Strings may also be created from other objects using the *note str: 44f.
constructor.

Since there is no separate “character” type, indexing a string produces
strings of length 1.  That is, for a non-empty string 's', ‘s[0] ==
s[0:1]’.

There is also no mutable string type, but *note str.join(): 2363. or
*note io.StringIO: f5e. can be used to efficiently construct strings
from multiple fragments.

Changed in version 3.3: For backwards compatibility with the Python 2
series, the ‘u’ prefix is once again permitted on string literals.  It
has no effect on the meaning of string literals and cannot be combined
with the ‘r’ prefix.

 -- Class: str (*, encoding='utf-8', errors='strict')

 -- Class: str (object)

 -- Class: str (object, encoding, errors='strict')

 -- Class: str (object, *, errors)

     Return a *note string: 1d92. version of 'object'.  If 'object' is
     not provided, returns the empty string.  Otherwise, the behavior of
     ‘str()’ depends on whether 'encoding' or 'errors' is given, as
     follows.

     If neither 'encoding' nor 'errors' is given, ‘str(object)’ returns
     *note type(object).__str__(object): 620, which is the “informal” or
     nicely printable string representation of 'object'.  For string
     objects, this is the string itself.  If 'object' does not have a
     ‘__str__()’ method, then *note str(): 44f. falls back to returning
     *note repr(object): 803.

     If at least one of 'encoding' or 'errors' is given, 'object' should
     be a *note bytes-like object: d55. (e.g.  *note bytes: 1c2. or
     *note bytearray: 2ea.).  In this case, if 'object' is a ‘bytes’ (or
     ‘bytearray’) object, then ‘str(bytes, encoding, errors)’ is
     equivalent to *note bytes.decode(encoding, errors): 8df.
     Otherwise, the bytes object underlying the buffer object is
     obtained before calling ‘bytes.decode()’.  See *note Binary
     Sequence Types — bytes, bytearray, memoryview: 231c. and *note
     Buffer Protocol: 2e8. for information on buffer objects.

     Passing a *note bytes: 1c2. object to *note str(): 44f. without the
     'encoding' or 'errors' arguments falls under the first case of
     returning the informal string representation (see also the *note
     -b: 5e6. command-line option to Python).  For example:

          >>> str(b'Zoot!')
          "b'Zoot!'"

     For more information on the ‘str’ class and its methods, see *note
     Text Sequence Type — str: 1d92. and the *note String Methods: 1d93.
     section below.  To output formatted strings, see the *note
     f-strings: 9b4. and *note Format string syntax: 13e8. sections.  In
     addition, see the *note Text Processing Services: 2374. section.

* Menu:

* String Methods: String Methods<2>.
* Formatted String Literals (f-strings): Formatted String Literals f-strings.
* printf-style String Formatting::


File: python.info,  Node: String Methods<2>,  Next: Formatted String Literals f-strings,  Up: Text Sequence Type — str

5.4.8.1 String Methods
......................

Strings implement all of the *note common: 2361. sequence operations,
along with the additional methods described below.

Strings also support two styles of string formatting, one providing a
large degree of flexibility and customization (see *note str.format():
624, *note Format string syntax: 13e8. and *note Custom string
formatting: 2376.) and the other based on C ‘printf’ style formatting
that handles a narrower range of types and is slightly harder to use
correctly, but is often faster for the cases it can handle (*note
printf-style String Formatting: 6cf.).

The *note Text Processing Services: 2377. section of the standard
library covers a number of other modules that provide various text
related utilities (including regular expression support in the *note re:
b9. module).

 -- Method: str.capitalize ()

     Return a copy of the string with its first character capitalized
     and the rest lowercased.

     Changed in version 3.8: The first character is now put into
     titlecase rather than uppercase.  This means that characters like
     digraphs will only have their first letter capitalized, instead of
     the full character.

 -- Method: str.casefold ()

     Return a casefolded copy of the string.  Casefolded strings may be
     used for caseless matching.

     Casefolding is similar to lowercasing but more aggressive because
     it is intended to remove all case distinctions in a string.  For
     example, the German lowercase letter ‘'ß'’ is equivalent to ‘"ss"’.
     Since it is already lowercase, *note lower(): 191c. would do
     nothing to ‘'ß'’; ‘casefold()’ converts it to ‘"ss"’.  For example:

          >>> 'straße'.lower()
          'straße'
          >>> 'straße'.casefold()
          'strasse'

     The casefolding algorithm is described in section 3.13 'Default
     Case Folding' of the Unicode Standard(1).

     Added in version 3.3.

 -- Method: str.center (width, fillchar=' ', /)

     Return centered in a string of length 'width'.  Padding is done
     using the specified 'fillchar' (default is an ASCII space).  The
     original string is returned if 'width' is less than or equal to
     ‘len(s)’.  For example:

          >>> 'Python'.center(10)
          '  Python  '
          >>> 'Python'.center(10, '-')
          '--Python--'
          >>> 'Python'.center(4)
          'Python'

 -- Method: str.count (sub[, start[, end]])

     Return the number of non-overlapping occurrences of substring 'sub'
     in the range ['start', 'end'].  Optional arguments 'start' and
     'end' are interpreted as in slice notation.

     If 'sub' is empty, returns the number of empty strings between
     characters which is the length of the string plus one.  For
     example:

          >>> 'spam, spam, spam'.count('spam')
          3
          >>> 'spam, spam, spam'.count('spam', 5)
          2
          >>> 'spam, spam, spam'.count('spam', 5, 10)
          1
          >>> 'spam, spam, spam'.count('eggs')
          0
          >>> 'spam, spam, spam'.count('')
          17

 -- Method: str.encode (encoding='utf-8', errors='strict')

     Return the string encoded to *note bytes: 1c2.

     'encoding' defaults to ‘'utf-8'’; see *note Standard Encodings:
     de7. for possible values.

     'errors' controls how encoding errors are handled.  If ‘'strict'’
     (the default), a *note UnicodeError: 12eb. exception is raised.
     Other possible values are ‘'ignore'’, ‘'replace'’,
     ‘'xmlcharrefreplace'’, ‘'backslashreplace'’ and any other name
     registered via *note codecs.register_error(): 14ea.  See *note
     Error Handlers: 1915. for details.

     For performance reasons, the value of 'errors' is not checked for
     validity unless an encoding error actually occurs, *note Python
     Development Mode: 1f8. is enabled or a *note debug build: 1f9. is
     used.  For example:

          >>> encoded_str_to_bytes = 'Python'.encode()
          >>> type(encoded_str_to_bytes)
          <class 'bytes'>
          >>> encoded_str_to_bytes
          b'Python'

     Changed in version 3.1: Added support for keyword arguments.

     Changed in version 3.9: The value of the 'errors' argument is now
     checked in *note Python Development Mode: 1f8. and in *note debug
     mode: 1f9.

 -- Method: str.endswith (suffix[, start[, end]])

     Return ‘True’ if the string ends with the specified 'suffix',
     otherwise return ‘False’.  'suffix' can also be a tuple of suffixes
     to look for.  With optional 'start', test beginning at that
     position.  With optional 'end', stop comparing at that position.
     Using 'start' and 'end' is equivalent to
     ‘str[start:end].endswith(suffix)’.  For example:

          >>> 'Python'.endswith('on')
          True
          >>> 'a tuple of suffixes'.endswith(('at', 'in'))
          False
          >>> 'a tuple of suffixes'.endswith(('at', 'es'))
          True
          >>> 'Python is amazing'.endswith('is', 0, 9)
          True

     See also *note startswith(): eff. and *note removesuffix(): 8d9.

 -- Method: str.expandtabs (tabsize=8)

     Return a copy of the string where all tab characters are replaced
     by one or more spaces, depending on the current column and the
     given tab size.  Tab positions occur every 'tabsize' characters
     (default is 8, giving tab positions at columns 0, 8, 16 and so on).
     To expand the string, the current column is set to zero and the
     string is examined character by character.  If the character is a
     tab (‘\t’), one or more space characters are inserted in the result
     until the current column is equal to the next tab position.  (The
     tab character itself is not copied.)  If the character is a newline
     (‘\n’) or return (‘\r’), it is copied and the current column is
     reset to zero.  Any other character is copied unchanged and the
     current column is incremented by one regardless of how the
     character is represented when printed.  For example:

          >>> '01\t012\t0123\t01234'.expandtabs()
          '01      012     0123    01234'
          >>> '01\t012\t0123\t01234'.expandtabs(4)
          '01  012 0123    01234'
          >>> print('01\t012\n0123\t01234'.expandtabs(4))
          01  012
          0123    01234

 -- Method: str.find (sub[, start[, end]])

     Return the lowest index in the string where substring 'sub' is
     found within the slice ‘s[start:end]’.  Optional arguments 'start'
     and 'end' are interpreted as in slice notation.  Return ‘-1’ if
     'sub' is not found.  For example:

          >>> 'spam, spam, spam'.find('sp')
          0
          >>> 'spam, spam, spam'.find('sp', 5)
          6

     See also *note rfind(): edd. and *note index(): 1750.

          Note: The ‘find()’ method should be used only if you need to
          know the position of 'sub'.  To check if 'sub' is a substring
          or not, use the *note in: 2f4. operator:

               >>> 'Py' in 'Python'
               True

 -- Method: str.format (*args, **kwargs)

     Perform a string formatting operation.  The string on which this
     method is called can contain literal text or replacement fields
     delimited by braces ‘{}’.  Each replacement field contains either
     the numeric index of a positional argument, or the name of a
     keyword argument.  Returns a copy of the string where each
     replacement field is replaced with the string value of the
     corresponding argument.  For example:

          >>> "The sum of 1 + 2 is {0}".format(1+2)
          'The sum of 1 + 2 is 3'
          >>> "The sum of {a} + {b} is {answer}".format(answer=1+2, a=1, b=2)
          'The sum of 1 + 2 is 3'
          >>> "{1} expects the {0} Inquisition!".format("Spanish", "Nobody")
          'Nobody expects the Spanish Inquisition!'

     See *note Format string syntax: 13e8. for a description of the
     various formatting options that can be specified in format strings.

          Note: When formatting a number (*note int: 257, *note float:
          2f7, *note complex: 2f8, *note decimal.Decimal: 29d. and
          subclasses) with the ‘n’ type (ex: ‘'{:n}'.format(1234)’), the
          function temporarily sets the ‘LC_CTYPE’ locale to the
          ‘LC_NUMERIC’ locale to decode ‘decimal_point’ and
          ‘thousands_sep’ fields of ‘localeconv()’ if they are non-ASCII
          or longer than 1 byte, and the ‘LC_NUMERIC’ locale is
          different than the ‘LC_CTYPE’ locale.  This temporary change
          affects other threads.

     Changed in version 3.7: When formatting a number with the ‘n’ type,
     the function sets temporarily the ‘LC_CTYPE’ locale to the
     ‘LC_NUMERIC’ locale in some cases.

 -- Method: str.format_map (mapping, /)

     Similar to ‘str.format(**mapping)’, except that ‘mapping’ is used
     directly and not copied to a *note dict: 256.  This is useful if
     for example ‘mapping’ is a dict subclass:

          >>> class Default(dict):
          ...     def __missing__(self, key):
          ...         return key
          ...
          >>> '{name} was born in {country}'.format_map(Default(name='Guido'))
          'Guido was born in country'

     Added in version 3.2.

 -- Method: str.index (sub[, start[, end]])

     Like *note find(): edc, but raise *note ValueError: 202. when the
     substring is not found.  For example:

          >>> 'spam, spam, spam'.index('spam')
          0
          >>> 'spam, spam, spam'.index('eggs')
          Traceback (most recent call last):
            File "<python-input-0>", line 1, in <module>
              'spam, spam, spam'.index('eggs')
              ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
          ValueError: substring not found

     See also *note rindex(): 129e.

 -- Method: str.isalnum ()

     Return ‘True’ if all characters in the string are alphanumeric and
     there is at least one character, ‘False’ otherwise.  A character
     ‘c’ is alphanumeric if one of the following returns ‘True’:
     ‘c.isalpha()’, ‘c.isdecimal()’, ‘c.isdigit()’, or ‘c.isnumeric()’.
     For example:

          >>> 'abc123'.isalnum()
          True
          >>> 'abc123!@#'.isalnum()
          False
          >>> ''.isalnum()
          False
          >>> ' '.isalnum()
          False

 -- Method: str.isalpha ()

     Return ‘True’ if all characters in the string are alphabetic and
     there is at least one character, ‘False’ otherwise.  Alphabetic
     characters are those characters defined in the Unicode character
     database as “Letter”, i.e., those with general category property
     being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”.  Note that this is
     different from the Alphabetic property defined in the section 4.10
     'Letters, Alphabetic, and Ideographic' of the Unicode Standard(2).
     For example:

          >>> 'Letters and spaces'.isalpha()
          False
          >>> 'LettersOnly'.isalpha()
          True
          >>> 'µ'.isalpha()  # non-ASCII characters can be considered alphabetical too
          True

     See *note Unicode Properties: 237c.

 -- Method: str.isascii ()

     Return ‘True’ if the string is empty or all characters in the
     string are ASCII, ‘False’ otherwise.  ASCII characters have code
     points in the range U+0000-U+007F. For example:

          >>> 'ASCII characters'.isascii()
          True
          >>> 'µ'.isascii()
          False

     Added in version 3.7.

 -- Method: str.isdecimal ()

     Return ‘True’ if all characters in the string are decimal
     characters and there is at least one character, ‘False’ otherwise.
     Decimal characters are those that can be used to form numbers in
     base 10, such as U+0660, ARABIC-INDIC DIGIT ZERO. Formally a
     decimal character is a character in the Unicode General Category
     “Nd”.  For example:

          >>> '0123456789'.isdecimal()
          True
          >>> '٠١٢٣٤٥٦٧٨٩'.isdecimal()  # Arabic-Indic digits zero to nine
          True
          >>> 'alphabetic'.isdecimal()
          False

 -- Method: str.isdigit ()

     Return ‘True’ if all characters in the string are digits and there
     is at least one character, ‘False’ otherwise.  Digits include
     decimal characters and digits that need special handling, such as
     the compatibility superscript digits.  This covers digits which
     cannot be used to form numbers in base 10, like the Kharosthi
     numbers.  Formally, a digit is a character that has the property
     value Numeric_Type=Digit or Numeric_Type=Decimal.

 -- Method: str.isidentifier ()

     Return ‘True’ if the string is a valid identifier according to the
     language definition, section *note Identifiers and keywords: 2040.

     *note keyword.iskeyword(): 237f. can be used to test whether string
     ‘s’ is a reserved identifier, such as *note def: 14a9. and *note
     class: 131f.

     Example:

          >>> from keyword import iskeyword

          >>> 'hello'.isidentifier(), iskeyword('hello')
          (True, False)
          >>> 'def'.isidentifier(), iskeyword('def')
          (True, True)

 -- Method: str.islower ()

     Return ‘True’ if all cased characters (3) in the string are
     lowercase and there is at least one cased character, ‘False’
     otherwise.

 -- Method: str.isnumeric ()

     Return ‘True’ if all characters in the string are numeric
     characters, and there is at least one character, ‘False’ otherwise.
     Numeric characters include digit characters, and all characters
     that have the Unicode numeric value property, e.g.  U+2155, VULGAR
     FRACTION ONE FIFTH. Formally, numeric characters are those with the
     property value Numeric_Type=Digit, Numeric_Type=Decimal or
     Numeric_Type=Numeric.  For example:

          >>> '0123456789'.isnumeric()
          True
          >>> '٠١٢٣٤٥٦٧٨٩'.isnumeric()  # Arabic-indic digit zero to nine
          True
          >>> '⅕'.isnumeric()  # Vulgar fraction one fifth
          True
          >>> '²'.isdecimal(), '²'.isdigit(),  '²'.isnumeric()
          (False, True, True)

     See also *note isdecimal(): 237d. and *note isdigit(): 237e.
     Numeric characters are a superset of decimal numbers.

 -- Method: str.isprintable ()

     Return ‘True’ if all characters in the string are printable,
     ‘False’ if it contains at least one non-printable character.

     Here “printable” means the character is suitable for *note repr():
     803. to use in its output; “non-printable” means that ‘repr()’ on
     built-in types will hex-escape the character.  It has no bearing on
     the handling of strings written to *note sys.stdout: aec. or *note
     sys.stderr: 943.

     The printable characters are those which in the Unicode character
     database (see *note unicodedata: 105.) have a general category in
     group Letter, Mark, Number, Punctuation, or Symbol (L, M, N, P, or
     S); plus the ASCII space 0x20.  Nonprintable characters are those
     in group Separator or Other (Z or C), except the ASCII space.

     For example:

          >>> ''.isprintable(), ' '.isprintable()
          (True, True)
          >>> '\t'.isprintable(), '\n'.isprintable()
          (False, False)

     See also *note isspace(): 2382.

 -- Method: str.isspace ()

     Return ‘True’ if there are only whitespace characters in the string
     and there is at least one character, ‘False’ otherwise.

     For example:

          >>> ''.isspace()
          False
          >>> ' '.isspace()
          True
          >>> '\t\n'.isspace() # TAB and BREAK LINE
          True
          >>> '\u3000'.isspace() # IDEOGRAPHIC SPACE
          True

     A character is 'whitespace' if in the Unicode character database
     (see *note unicodedata: 105.), either its general category is ‘Zs’
     (“Separator, space”), or its bidirectional class is one of ‘WS’,
     ‘B’, or ‘S’.

     See also *note isprintable(): e08.

 -- Method: str.istitle ()

     Return ‘True’ if the string is a titlecased string and there is at
     least one character, for example uppercase characters may only
     follow uncased characters and lowercase characters only cased ones.
     Return ‘False’ otherwise.

     For example:

          >>> 'Spam, Spam, Spam'.istitle()
          True
          >>> 'spam, spam, spam'.istitle()
          False
          >>> 'SPAM, SPAM, SPAM'.istitle()
          False

     See also *note title(): 2384.

 -- Method: str.isupper ()

     Return ‘True’ if all cased characters (4) in the string are
     uppercase and there is at least one cased character, ‘False’
     otherwise.

          >>> 'BANANA'.isupper()
          True
          >>> 'banana'.isupper()
          False
          >>> 'baNana'.isupper()
          False
          >>> ' '.isupper()
          False

 -- Method: str.join (iterable, /)

     Return a string which is the concatenation of the strings in
     'iterable'.  A *note TypeError: 2c3. will be raised if there are
     any non-string values in 'iterable', including *note bytes: 1c2.
     objects.  The separator between elements is the string providing
     this method.  For example:

          >>> ', '.join(['spam', 'spam', 'spam'])
          'spam, spam, spam'
          >>> '-'.join('Python')
          'P-y-t-h-o-n'

     See also *note split(): ede.

 -- Method: str.ljust (width, fillchar=' ', /)

     Return the string left justified in a string of length 'width'.
     Padding is done using the specified 'fillchar' (default is an ASCII
     space).  The original string is returned if 'width' is less than or
     equal to ‘len(s)’.

     For example:

          >>> 'Python'.ljust(10)
          'Python    '
          >>> 'Python'.ljust(10, '.')
          'Python....'
          >>> 'Monty Python'.ljust(10, '.')
          'Monty Python'

     See also *note rjust(): 1e19.

 -- Method: str.lower ()

     Return a copy of the string with all the cased characters (5)
     converted to lowercase.  For example:

          >>> 'Lower Method Example'.lower()
          'lower method example'

     The lowercasing algorithm used is described in section 3.13
     'Default Case Folding' of the Unicode Standard(6).

 -- Method: str.lstrip (chars=None, /)

     Return a copy of the string with leading characters removed.  The
     'chars' argument is a string specifying the set of characters to be
     removed.  If omitted or ‘None’, the 'chars' argument defaults to
     removing whitespace.  The 'chars' argument is not a prefix; rather,
     all combinations of its values are stripped:

          >>> '   spacious   '.lstrip()
          'spacious   '
          >>> 'www.example.com'.lstrip('cmowz.')
          'example.com'

     See *note str.removeprefix(): 8d8. for a method that will remove a
     single prefix string rather than all of a set of characters.  For
     example:

          >>> 'Arthur: three!'.lstrip('Arthur: ')
          'ee!'
          >>> 'Arthur: three!'.removeprefix('Arthur: ')
          'three!'

 -- Method: static str.maketrans (dict, /)

 -- Method: static str.maketrans (from, to, remove='', /)

     This static method returns a translation table usable for *note
     str.translate(): 2387.

     If there is only one argument, it must be a dictionary mapping
     Unicode ordinals (integers) or characters (strings of length 1) to
     Unicode ordinals, strings (of arbitrary lengths) or ‘None’.
     Character keys will then be converted to ordinals.

     If there are two arguments, they must be strings of equal length,
     and in the resulting dictionary, each character in 'from' will be
     mapped to the character at the same position in 'to'.  If there is
     a third argument, it must be a string, whose characters will be
     mapped to ‘None’ in the result.

 -- Method: str.partition (sep, /)

     Split the string at the first occurrence of 'sep', and return a
     3-tuple containing the part before the separator, the separator
     itself, and the part after the separator.  If the separator is not
     found, return a 3-tuple containing the string itself, followed by
     two empty strings.

     For example:

          >>> 'Monty Python'.partition(' ')
          ('Monty', ' ', 'Python')
          >>> "Monty Python's Flying Circus".partition(' ')
          ('Monty', ' ', "Python's Flying Circus")
          >>> 'Monty Python'.partition('-')
          ('Monty Python', '', '')

     See also *note rpartition(): 129f.

 -- Method: str.removeprefix (prefix, /)

     If the string starts with the 'prefix' string, return
     ‘string[len(prefix):]’.  Otherwise, return a copy of the original
     string:

          >>> 'TestHook'.removeprefix('Test')
          'Hook'
          >>> 'BaseTestCase'.removeprefix('Test')
          'BaseTestCase'

     Added in version 3.9.

     See also *note removesuffix(): 8d9. and *note startswith(): eff.

 -- Method: str.removesuffix (suffix, /)

     If the string ends with the 'suffix' string and that 'suffix' is
     not empty, return ‘string[:-len(suffix)]’.  Otherwise, return a
     copy of the original string:

          >>> 'MiscTests'.removesuffix('Tests')
          'Misc'
          >>> 'TmpDirMixin'.removesuffix('Tests')
          'TmpDirMixin'

     Added in version 3.9.

     See also *note removeprefix(): 8d8. and *note endswith(): f00.

 -- Method: str.replace (old, new, /, count=-1)

     Return a copy of the string with all occurrences of substring 'old'
     replaced by 'new'.  If 'count' is given, only the first 'count'
     occurrences are replaced.  If 'count' is not specified or ‘-1’,
     then all occurrences are replaced.  For example:

          >>> 'spam, spam, spam'.replace('spam', 'eggs')
          'eggs, eggs, eggs'
          >>> 'spam, spam, spam'.replace('spam', 'eggs', 1)
          'eggs, spam, spam'

     Changed in version 3.13: 'count' is now supported as a keyword
     argument.

 -- Method: str.rfind (sub[, start[, end]])

     Return the highest index in the string where substring 'sub' is
     found, such that 'sub' is contained within ‘s[start:end]’.
     Optional arguments 'start' and 'end' are interpreted as in slice
     notation.  Return ‘-1’ on failure.  For example:

          >>> 'spam, spam, spam'.rfind('sp')
          12
          >>> 'spam, spam, spam'.rfind('sp', 0, 10)
          6

     See also *note find(): edc. and *note rindex(): 129e.

 -- Method: str.rindex (sub[, start[, end]])

     Like *note rfind(): edd. but raises *note ValueError: 202. when the
     substring 'sub' is not found.  For example:

          >>> 'spam, spam, spam'.rindex('spam')
          12
          >>> 'spam, spam, spam'.rindex('eggs')
          Traceback (most recent call last):
            File "<stdin-0>", line 1, in <module>
              'spam, spam, spam'.rindex('eggs')
              ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
          ValueError: substring not found

     See also *note index(): 1750. and *note find(): edc.

 -- Method: str.rjust (width, fillchar=' ', /)

     Return the string right justified in a string of length 'width'.
     Padding is done using the specified 'fillchar' (default is an ASCII
     space).  The original string is returned if 'width' is less than or
     equal to ‘len(s)’.

     For example:

          >>> 'Python'.rjust(10)
          '    Python'
          >>> 'Python'.rjust(10, '.')
          '....Python'
          >>> 'Monty Python'.rjust(10, '.')
          'Monty Python'

     See also *note ljust(): 1e1a. and *note zfill(): 1501.

 -- Method: str.rpartition (sep, /)

     Split the string at the last occurrence of 'sep', and return a
     3-tuple containing the part before the separator, the separator
     itself, and the part after the separator.  If the separator is not
     found, return a 3-tuple containing two empty strings, followed by
     the string itself.

     For example:

          >>> 'Monty Python'.rpartition(' ')
          ('Monty', ' ', 'Python')
          >>> "Monty Python's Flying Circus".rpartition(' ')
          ("Monty Python's Flying", ' ', 'Circus')
          >>> 'Monty Python'.rpartition('-')
          ('', '', 'Monty Python')

     See also *note partition(): edf.

 -- Method: str.rsplit (sep=None, maxsplit=-1)

     Return a list of the words in the string, using 'sep' as the
     delimiter string.  If 'maxsplit' is given, at most 'maxsplit'
     splits are done, the 'rightmost' ones.  If 'sep' is not specified
     or ‘None’, any whitespace string is a separator.  Except for
     splitting from the right, ‘rsplit()’ behaves like *note split():
     ede. which is described in detail below.

 -- Method: str.rstrip (chars=None, /)

     Return a copy of the string with trailing characters removed.  The
     'chars' argument is a string specifying the set of characters to be
     removed.  If omitted or ‘None’, the 'chars' argument defaults to
     removing whitespace.  The 'chars' argument is not a suffix; rather,
     all combinations of its values are stripped.  For example:

          >>> '   spacious   '.rstrip()
          '   spacious'
          >>> 'mississippi'.rstrip('ipz')
          'mississ'

     See *note removesuffix(): 8d9. for a method that will remove a
     single suffix string rather than all of a set of characters.  For
     example:

          >>> 'Monty Python'.rstrip(' Python')
          'M'
          >>> 'Monty Python'.removesuffix(' Python')
          'Monty'

     See also *note strip(): 14fe.

 -- Method: str.split (sep=None, maxsplit=-1)

     Return a list of the words in the string, using 'sep' as the
     delimiter string.  If 'maxsplit' is given, at most 'maxsplit'
     splits are done (thus, the list will have at most ‘maxsplit+1’
     elements).  If 'maxsplit' is not specified or ‘-1’, then there is
     no limit on the number of splits (all possible splits are made).

     If 'sep' is given, consecutive delimiters are not grouped together
     and are deemed to delimit empty strings (for example,
     ‘'1,,2'.split(',')’ returns ‘['1', '', '2']’).  The 'sep' argument
     may consist of multiple characters as a single delimiter (to split
     with multiple delimiters, use *note re.split(): 2a2.).  Splitting
     an empty string with a specified separator returns ‘['']’.

     For example:

          >>> '1,2,3'.split(',')
          ['1', '2', '3']
          >>> '1,2,3'.split(',', maxsplit=1)
          ['1', '2,3']
          >>> '1,2,,3,'.split(',')
          ['1', '2', '', '3', '']
          >>> '1<>2<>3<4'.split('<>')
          ['1', '2', '3<4']

     If 'sep' is not specified or is ‘None’, a different splitting
     algorithm is applied: runs of consecutive whitespace are regarded
     as a single separator, and the result will contain no empty strings
     at the start or end if the string has leading or trailing
     whitespace.  Consequently, splitting an empty string or a string
     consisting of just whitespace with a ‘None’ separator returns ‘[]’.

     For example:

          >>> '1 2 3'.split()
          ['1', '2', '3']
          >>> '1 2 3'.split(maxsplit=1)
          ['1', '2 3']
          >>> '   1   2   3   '.split()
          ['1', '2', '3']

     If 'sep' is not specified or is ‘None’ and 'maxsplit' is ‘0’, only
     leading runs of consecutive whitespace are considered.

     For example:

          >>> "".split(None, 0)
          []
          >>> "   ".split(None, 0)
          []
          >>> "   foo   ".split(maxsplit=0)
          ['foo   ']

     See also *note join(): 2363.

 -- Method: str.splitlines (keepends=False)

     Return a list of the lines in the string, breaking at line
     boundaries.  Line breaks are not included in the resulting list
     unless 'keepends' is given and true.

     This method splits on the following line boundaries.  In
     particular, the boundaries are a superset of *note universal
     newlines: d62.

     Representation              Description
                                 
     --------------------------------------------------------------
                                 
     ‘\n’                        Line Feed
                                 
                                 
     ‘\r’                        Carriage Return
                                 
                                 
     ‘\r\n’                      Carriage Return + Line Feed
                                 
                                 
     ‘\v’ or ‘\x0b’              Line Tabulation
                                 
                                 
     ‘\f’ or ‘\x0c’              Form Feed
                                 
                                 
     ‘\x1c’                      File Separator
                                 
                                 
     ‘\x1d’                      Group Separator
                                 
                                 
     ‘\x1e’                      Record Separator
                                 
                                 
     ‘\x85’                      Next Line (C1 Control Code)
                                 
                                 
     ‘\u2028’                    Line Separator
                                 
                                 
     ‘\u2029’                    Paragraph Separator
                                 

     Changed in version 3.2: ‘\v’ and ‘\f’ added to list of line
     boundaries.

     For example:

          >>> 'ab c\n\nde fg\rkl\r\n'.splitlines()
          ['ab c', '', 'de fg', 'kl']
          >>> 'ab c\n\nde fg\rkl\r\n'.splitlines(keepends=True)
          ['ab c\n', '\n', 'de fg\r', 'kl\r\n']

     Unlike *note split(): ede. when a delimiter string 'sep' is given,
     this method returns an empty list for the empty string, and a
     terminal line break does not result in an extra line:

          >>> "".splitlines()
          []
          >>> "One line\n".splitlines()
          ['One line']

     For comparison, ‘split('\n')’ gives:

          >>> ''.split('\n')
          ['']
          >>> 'Two lines\n'.split('\n')
          ['Two lines', '']

 -- Method: str.startswith (prefix[, start[, end]])

     Return ‘True’ if string starts with the 'prefix', otherwise return
     ‘False’.  'prefix' can also be a tuple of prefixes to look for.
     With optional 'start', test string beginning at that position.
     With optional 'end', stop comparing string at that position.

     For example:

          >>> 'Python'.startswith('Py')
          True
          >>> 'a tuple of prefixes'.startswith(('at', 'a'))
          True
          >>> 'Python is amazing'.startswith('is', 7)
          True

     See also *note endswith(): f00. and *note removeprefix(): 8d8.

 -- Method: str.strip (chars=None, /)

     Return a copy of the string with the leading and trailing
     characters removed.  The 'chars' argument is a string specifying
     the set of characters to be removed.  If omitted or ‘None’, the
     'chars' argument defaults to removing whitespace.  The 'chars'
     argument is not a prefix or suffix; rather, all combinations of its
     values are stripped.

     For example:

          >>> '   spacious   '.strip()
          'spacious'
          >>> 'www.example.com'.strip('cmowz.')
          'example'

     The outermost leading and trailing 'chars' argument values are
     stripped from the string.  Characters are removed from the leading
     end until reaching a string character that is not contained in the
     set of characters in 'chars'.  A similar action takes place on the
     trailing end.

     For example:

          >>> comment_string = '#....... Section 3.2.1 Issue #32 .......'
          >>> comment_string.strip('.#! ')
          'Section 3.2.1 Issue #32'

     See also *note rstrip(): 1500.

 -- Method: str.swapcase ()

     Return a copy of the string with uppercase characters converted to
     lowercase and vice versa.  Note that it is not necessarily true
     that ‘s.swapcase().swapcase() == s’.

 -- Method: str.title ()

     Return a titlecased version of the string where words start with an
     uppercase character and the remaining characters are lowercase.

     For example:

          >>> 'Hello world'.title()
          'Hello World'

     The algorithm uses a simple language-independent definition of a
     word as groups of consecutive letters.  The definition works in
     many contexts but it means that apostrophes in contractions and
     possessives form word boundaries, which may not be the desired
     result:

          >>> "they're bill's friends from the UK".title()
          "They'Re Bill'S Friends From The Uk"

     The *note string.capwords(): 2389. function does not have this
     problem, as it splits words on spaces only.

     Alternatively, a workaround for apostrophes can be constructed
     using regular expressions:

          >>> import re
          >>> def titlecase(s):
          ...     return re.sub(r"[A-Za-z]+('[A-Za-z]+)?",
          ...                   lambda mo: mo.group(0).capitalize(),
          ...                   s)
          ...
          >>> titlecase("they're bill's friends.")
          "They're Bill's Friends."

     See also *note istitle(): 2383.

 -- Method: str.translate (table, /)

     Return a copy of the string in which each character has been mapped
     through the given translation table.  The table must be an object
     that implements indexing via *note __getitem__(): 283, typically a
     *note mapping: 1200. or *note sequence: 4f4.  When indexed by a
     Unicode ordinal (an integer), the table object can do any of the
     following: return a Unicode ordinal or a string, to map the
     character to one or more other characters; return ‘None’, to delete
     the character from the return string; or raise a *note LookupError:
     238a. exception, to map the character to itself.

     You can use *note str.maketrans(): e09. to create a translation map
     from character-to-character mappings in different formats.

     See also the *note codecs: 1b. module for a more flexible approach
     to custom character mappings.

 -- Method: str.upper ()

     Return a copy of the string with all the cased characters (7)
     converted to uppercase.  Note that ‘s.upper().isupper()’ might be
     ‘False’ if ‘s’ contains uncased characters or if the Unicode
     category of the resulting character(s) is not “Lu” (Letter,
     uppercase), but e.g.  “Lt” (Letter, titlecase).

     The uppercasing algorithm used is described in section 3.13
     'Default Case Folding' of the Unicode Standard(8).

 -- Method: str.zfill (width, /)

     Return a copy of the string left filled with ASCII ‘'0'’ digits to
     make a string of length 'width'.  A leading sign prefix
     (‘'+'’/‘'-'’) is handled by inserting the padding 'after' the sign
     character rather than before.  The original string is returned if
     'width' is less than or equal to ‘len(s)’.

     For example:

          >>> "42".zfill(5)
          '00042'
          >>> "-42".zfill(5)
          '-0042'

     See also *note rjust(): 1e19.

   ---------- Footnotes ----------

   (1) https://www.unicode.org/versions/Unicode15.1.0/ch03.pdf

   (2) https://www.unicode.org/versions/Unicode15.1.0/ch04.pdf

   (3) Cased characters are those with general category property being
one of “Lu” (Letter, uppercase), “Ll” (Letter, lowercase), or “Lt”
(Letter, titlecase).

   (4) Cased characters are those with general category property being
one of “Lu” (Letter, uppercase), “Ll” (Letter, lowercase), or “Lt”
(Letter, titlecase).

   (5) Cased characters are those with general category property being
one of “Lu” (Letter, uppercase), “Ll” (Letter, lowercase), or “Lt”
(Letter, titlecase).

   (6) https://www.unicode.org/versions/Unicode15.1.0/ch03.pdf

   (7) Cased characters are those with general category property being
one of “Lu” (Letter, uppercase), “Ll” (Letter, lowercase), or “Lt”
(Letter, titlecase).

   (8) https://www.unicode.org/versions/Unicode15.1.0/ch03.pdf


File: python.info,  Node: Formatted String Literals f-strings,  Next: printf-style String Formatting,  Prev: String Methods<2>,  Up: Text Sequence Type — str

5.4.8.2 Formatted String Literals (f-strings)
.............................................

Added in version 3.6.

Changed in version 3.7: The *note await: 1b9. and *note async for: ac0.
can be used in expressions within f-strings.

Changed in version 3.8: Added the debugging operator (‘=’)

Changed in version 3.12: Many restrictions on expressions within
f-strings have been removed.  Notably, nested strings, comments, and
backslashes are now permitted.

An 'f-string' (formally a 'formatted string literal') is a string
literal that is prefixed with ‘f’ or ‘F’.  This type of string literal
allows embedding arbitrary Python expressions within 'replacement
fields', which are delimited by curly brackets (‘{}’).  These
expressions are evaluated at runtime, similarly to *note str.format():
624, and are converted into regular *note str: 44f. objects.  For
example:

     >>> who = 'nobody'
     >>> nationality = 'Spanish'
     >>> f'{who.title()} expects the {nationality} Inquisition!'
     'Nobody expects the Spanish Inquisition!'

It is also possible to use a multi line f-string:

     >>> f'''This is a string
     ... on two lines'''
     'This is a string\non two lines'

A single opening curly bracket, ‘'{'’, marks a 'replacement field' that
can contain any Python expression:

     >>> nationality = 'Spanish'
     >>> f'The {nationality} Inquisition!'
     'The Spanish Inquisition!'

To include a literal ‘{’ or ‘}’, use a double bracket:

     >>> x = 42
     >>> f'{{x}} is {x}'
     '{x} is 42'

Functions can also be used, and *note format specifiers: 13e8.:

     >>> from math import sqrt
     >>> f'√2 \N{ALMOST EQUAL TO} {sqrt(2):.5f}'
     '√2 ≈ 1.41421'

Any non-string expression is converted using *note str(): 44f, by
default:

     >>> from fractions import Fraction
     >>> f'{Fraction(1, 3)}'
     '1/3'

To use an explicit conversion, use the ‘!’ (exclamation mark) operator,
followed by any of the valid formats, which are:

Conversion     Meaning
               
----------------------------------
               
‘!a’           *note ascii(): 1434.
               
               
‘!r’           *note repr(): 803.
               
               
‘!s’           *note str(): 44f.
               

For example:

     >>> from fractions import Fraction
     >>> f'{Fraction(1, 3)!s}'
     '1/3'
     >>> f'{Fraction(1, 3)!r}'
     'Fraction(1, 3)'
     >>> question = '¿Dónde está el Presidente?'
     >>> print(f'{question!a}')
     '\xbfD\xf3nde est\xe1 el Presidente?'

While debugging it may be helpful to see both the expression and its
value, by using the equals sign (‘=’) after the expression.  This
preserves spaces within the brackets, and can be used with a converter.
By default, the debugging operator uses the *note repr(): 803. (‘!r’)
conversion.  For example:

     >>> from fractions import Fraction
     >>> calculation = Fraction(1, 3)
     >>> f'{calculation=}'
     'calculation=Fraction(1, 3)'
     >>> f'{calculation = }'
     'calculation = Fraction(1, 3)'
     >>> f'{calculation = !s}'
     'calculation = 1/3'

Once the output has been evaluated, it can be formatted using a *note
format specifier: 13e8. following a colon (‘':'’).  After the expression
has been evaluated, and possibly converted to a string, the
‘__format__()’ method of the result is called with the format specifier,
or the empty string if no format specifier is given.  The formatted
result is then used as the final value for the replacement field.  For
example:

     >>> from fractions import Fraction
     >>> f'{Fraction(1, 7):.6f}'
     '0.142857'
     >>> f'{Fraction(1, 7):_^+10}'
     '___+1/7___'


File: python.info,  Node: printf-style String Formatting,  Prev: Formatted String Literals f-strings,  Up: Text Sequence Type — str

5.4.8.3 ‘printf’-style String Formatting
........................................

     Note: The formatting operations described here exhibit a variety of
     quirks that lead to a number of common errors (such as failing to
     display tuples and dictionaries correctly).  Using the newer *note
     formatted string literals: 9b4, the *note str.format(): 624.
     interface, or *note template strings: 238e. may help avoid these
     errors.  Each of these alternatives provides their own trade-offs
     and benefits of simplicity, flexibility, and/or extensibility.

String objects have one unique built-in operation: the ‘%’ operator
(modulo).  This is also known as the string 'formatting' or
'interpolation' operator.  Given ‘format % values’ (where 'format' is a
string), ‘%’ conversion specifications in 'format' are replaced with
zero or more elements of 'values'.  The effect is similar to using the
‘sprintf()’ function in the C language.  For example:

     >>> print('%s has %d quote types.' % ('Python', 2))
     Python has 2 quote types.

If 'format' requires a single argument, 'values' may be a single
non-tuple object.  (1)  Otherwise, 'values' must be a tuple with exactly
the number of items specified by the format string, or a single mapping
object (for example, a dictionary).

A conversion specifier contains two or more characters and has the
following components, which must occur in this order:

  1. The ‘'%'’ character, which marks the start of the specifier.

  2. Mapping key (optional), consisting of a parenthesised sequence of
     characters (for example, ‘(somename)’).

  3. Conversion flags (optional), which affect the result of some
     conversion types.

  4. Minimum field width (optional).  If specified as an ‘'*'’
     (asterisk), the actual width is read from the next element of the
     tuple in 'values', and the object to convert comes after the
     minimum field width and optional precision.

  5. Precision (optional), given as a ‘'.'’ (dot) followed by the
     precision.  If specified as ‘'*'’ (an asterisk), the actual
     precision is read from the next element of the tuple in 'values',
     and the value to convert comes after the precision.

  6. Length modifier (optional).

  7. Conversion type.

When the right argument is a dictionary (or other mapping type), then
the formats in the string 'must' include a parenthesised mapping key
into that dictionary inserted immediately after the ‘'%'’ character.
The mapping key selects the value to be formatted from the mapping.  For
example:

     >>> print('%(language)s has %(number)03d quote types.' %
     ...       {'language': "Python", "number": 2})
     Python has 002 quote types.

In this case no ‘*’ specifiers may occur in a format (since they require
a sequential parameter list).

The conversion flag characters are:

Flag          Meaning
              
----------------------------------------------------------------------------------------
              
‘'#'’         The value conversion will use the “alternate form” (where defined
              below).
              
              
‘'0'’         The conversion will be zero padded for numeric values.
              
              
‘'-'’         The converted value is left adjusted (overrides the ‘'0'’ conversion if
              both are given).
              
              
‘' '’         (a space) A blank should be left before a positive number (or empty
              string) produced by a signed conversion.
              
              
‘'+'’         A sign character (‘'+'’ or ‘'-'’) will precede the conversion
              (overrides a “space” flag).
              

A length modifier (‘h’, ‘l’, or ‘L’) may be present, but is ignored as
it is not necessary for Python – so e.g.  ‘%ld’ is identical to ‘%d’.

The conversion types are:

Conversion       Meaning                                                   Notes
                                                                           
---------------------------------------------------------------------------------------
                                                                           
‘'d'’            Signed integer decimal.
                 
                                                                           
‘'i'’            Signed integer decimal.
                 
                                                                           
‘'o'’            Signed octal value.                                       (1)
                                                                           
                                                                           
‘'u'’            Obsolete type – it is identical to ‘'d'’.                 (6)
                                                                           
                                                                           
‘'x'’            Signed hexadecimal (lowercase).                           (2)
                                                                           
                                                                           
‘'X'’            Signed hexadecimal (uppercase).                           (2)
                                                                           
                                                                           
‘'e'’            Floating-point exponential format (lowercase).            (3)
                                                                           
                                                                           
‘'E'’            Floating-point exponential format (uppercase).            (3)
                                                                           
                                                                           
‘'f'’            Floating-point decimal format.                            (3)
                                                                           
                                                                           
‘'F'’            Floating-point decimal format.                            (3)
                                                                           
                                                                           
‘'g'’            Floating-point format.  Uses lowercase exponential        (4)
                 format if exponent is less than -4 or not less than       
                 precision, decimal format otherwise.
                 
                                                                           
‘'G'’            Floating-point format.  Uses uppercase exponential        (4)
                 format if exponent is less than -4 or not less than       
                 precision, decimal format otherwise.
                 
                                                                           
‘'c'’            Single character (accepts integer or single character
                 string).
                 
                                                                           
‘'r'’            String (converts any Python object using                  (5)
                 *note repr(): 803.).                                      
                 
                                                                           
‘'s'’            String (converts any Python object using                  (5)
                 *note str(): 44f.).                                       
                 
                                                                           
‘'a'’            String (converts any Python object using                  (5)
                 *note ascii(): 1434.).                                    
                 
                                                                           
‘'%'’            No argument is converted, results in a ‘'%'’ character
                 in the result.
                 

For floating-point formats, the result should be correctly rounded to a
given precision ‘p’ of digits after the decimal point.  The rounding
mode matches that of the *note round(): 1322. builtin.

Notes:

  1. The alternate form causes a leading octal specifier (‘'0o'’) to be
     inserted before the first digit.

  2. The alternate form causes a leading ‘'0x'’ or ‘'0X'’ (depending on
     whether the ‘'x'’ or ‘'X'’ format was used) to be inserted before
     the first digit.

  3. The alternate form causes the result to always contain a decimal
     point, even if no digits follow it.

     The precision determines the number of digits after the decimal
     point and defaults to 6.

  4. The alternate form causes the result to always contain a decimal
     point, and trailing zeroes are not removed as they would otherwise
     be.

     The precision determines the number of significant digits before
     and after the decimal point and defaults to 6.

  5. If precision is ‘N’, the output is truncated to ‘N’ characters.

  6. See PEP 237(2).

Since Python strings have an explicit length, ‘%s’ conversions do not
assume that ‘'\0'’ is the end of the string.

Changed in version 3.1: ‘%f’ conversions for numbers whose absolute
value is over 1e50 are no longer replaced by ‘%g’ conversions.

   ---------- Footnotes ----------

   (1) To format only a tuple you should therefore provide a singleton
tuple whose only element is the tuple to be formatted.

   (2) https://peps.python.org/pep-0237/


File: python.info,  Node: Binary Sequence Types — bytes bytearray memoryview,  Next: Set Types — set frozenset,  Prev: Text Sequence Type — str,  Up: Built-in Types

5.4.9 Binary Sequence Types — ‘bytes’, ‘bytearray’, ‘memoryview’
----------------------------------------------------------------

The core built-in types for manipulating binary data are *note bytes:
1c2. and *note bytearray: 2ea.  They are supported by *note memoryview:
2eb. which uses the *note buffer protocol: 2e8. to access the memory of
other binary objects without needing to make a copy.

The *note array: 7. module supports efficient storage of basic data
types like 32-bit integers and IEEE754 double-precision floating values.

* Menu:

* Bytes Objects::
* Bytearray Objects::
* Bytes and Bytearray Operations::
* printf-style Bytes Formatting::
* Memory Views::


File: python.info,  Node: Bytes Objects,  Next: Bytearray Objects,  Up: Binary Sequence Types — bytes bytearray memoryview

5.4.9.1 Bytes Objects
.....................

Bytes objects are immutable sequences of single bytes.  Since many major
binary protocols are based on the ASCII text encoding, bytes objects
offer several methods that are only valid when working with ASCII
compatible data and are closely related to string objects in a variety
of other ways.

 -- Class: bytes (source=b'')

 -- Class: bytes (source, encoding, errors='strict')

     Firstly, the syntax for bytes literals is largely the same as that
     for string literals, except that a ‘b’ prefix is added:

        * Single quotes: ‘b'still allows embedded "double" quotes'’

        * Double quotes: ‘b"still allows embedded 'single' quotes"’

        * Triple quoted: ‘b'''3 single quotes'''’, ‘b"""3 double
          quotes"""’

     Only ASCII characters are permitted in bytes literals (regardless
     of the declared source code encoding).  Any binary values over 127
     must be entered into bytes literals using the appropriate escape
     sequence.

     As with string literals, bytes literals may also use a ‘r’ prefix
     to disable processing of escape sequences.  See *note String and
     Bytes literals: 2050. for more about the various forms of bytes
     literal, including supported escape sequences.

     While bytes literals and representations are based on ASCII text,
     bytes objects actually behave like immutable sequences of integers,
     with each value in the sequence restricted such that ‘0 <= x < 256’
     (attempts to violate this restriction will trigger *note
     ValueError: 202.).  This is done deliberately to emphasise that
     while many binary formats include ASCII based elements and can be
     usefully manipulated with some text-oriented algorithms, this is
     not generally the case for arbitrary binary data (blindly applying
     text processing algorithms to binary data formats that are not
     ASCII compatible will usually lead to data corruption).

     In addition to the literal forms, bytes objects can be created in a
     number of other ways:

        * A zero-filled bytes object of a specified length: ‘bytes(10)’

        * From an iterable of integers: ‘bytes(range(20))’

        * Copying existing binary data via the buffer protocol:
          ‘bytes(obj)’

     Also see the *note bytes: 1c4b. built-in.

     Since 2 hexadecimal digits correspond precisely to a single byte,
     hexadecimal numbers are a commonly used format for describing
     binary data.  Accordingly, the bytes type has an additional class
     method to read data in that format:

      -- Method: classmethod fromhex (string, /)

          This ‘bytes’ class method returns a bytes object, decoding the
          given string object.  The string must contain two hexadecimal
          digits per byte, with ASCII whitespace being ignored.

               >>> bytes.fromhex('2Ef0 F1f2  ')
               b'.\xf0\xf1\xf2'

          Changed in version 3.7: ‘bytes.fromhex()’ now skips all ASCII
          whitespace in the string, not just spaces.

     A reverse conversion function exists to transform a bytes object
     into its hexadecimal representation.

      -- Method: hex (*, bytes_per_sep=1)

      -- Method: hex (sep, bytes_per_sep=1)

          Return a string object containing two hexadecimal digits for
          each byte in the instance.

               >>> b'\xf0\xf1\xf2'.hex()
               'f0f1f2'

          If you want to make the hex string easier to read, you can
          specify a single character separator 'sep' parameter to
          include in the output.  By default, this separator will be
          included between each byte.  A second optional 'bytes_per_sep'
          parameter controls the spacing.  Positive values calculate the
          separator position from the right, negative values from the
          left.

               >>> value = b'\xf0\xf1\xf2'
               >>> value.hex('-')
               'f0-f1-f2'
               >>> value.hex('_', 2)
               'f0_f1f2'
               >>> b'UUDDLRLRAB'.hex(' ', -4)
               '55554444 4c524c52 4142'

          Added in version 3.5.

          Changed in version 3.8: ‘bytes.hex()’ now supports optional
          'sep' and 'bytes_per_sep' parameters to insert separators
          between bytes in the hex output.

Since bytes objects are sequences of integers (akin to a tuple), for a
bytes object 'b', ‘b[0]’ will be an integer, while ‘b[0:1]’ will be a
bytes object of length 1.  (This contrasts with text strings, where both
indexing and slicing will produce a string of length 1)

The representation of bytes objects uses the literal format (‘b'...'’)
since it is often more useful than e.g.  ‘bytes([46, 46, 46])’.  You can
always convert a bytes object into a list of integers using ‘list(b)’.


File: python.info,  Node: Bytearray Objects,  Next: Bytes and Bytearray Operations,  Prev: Bytes Objects,  Up: Binary Sequence Types — bytes bytearray memoryview

5.4.9.2 Bytearray Objects
.........................

*note bytearray: 2ea. objects are a mutable counterpart to *note bytes:
1c2. objects.

 -- Class: bytearray (source=b'')

 -- Class: bytearray (source, encoding, errors='strict')

     There is no dedicated literal syntax for bytearray objects, instead
     they are always created by calling the constructor:

        * Creating an empty instance: ‘bytearray()’

        * Creating a zero-filled instance with a given length:
          ‘bytearray(10)’

        * From an iterable of integers: ‘bytearray(range(20))’

        * Copying existing binary data via the buffer protocol:
          ‘bytearray(b'Hi!')’

     As bytearray objects are mutable, they support the *note mutable:
     231a. sequence operations in addition to the common bytes and
     bytearray operations described in *note Bytes and Bytearray
     Operations: 231b.

     Also see the *note bytearray: 1c4c. built-in.

     Since 2 hexadecimal digits correspond precisely to a single byte,
     hexadecimal numbers are a commonly used format for describing
     binary data.  Accordingly, the bytearray type has an additional
     class method to read data in that format:

      -- Method: classmethod fromhex (string, /)

          This ‘bytearray’ class method returns bytearray object,
          decoding the given string object.  The string must contain two
          hexadecimal digits per byte, with ASCII whitespace being
          ignored.

               >>> bytearray.fromhex('2Ef0 F1f2  ')
               bytearray(b'.\xf0\xf1\xf2')

          Changed in version 3.7: ‘bytearray.fromhex()’ now skips all
          ASCII whitespace in the string, not just spaces.

     A reverse conversion function exists to transform a bytearray
     object into its hexadecimal representation.

      -- Method: hex (*, bytes_per_sep=1)

      -- Method: hex (sep, bytes_per_sep=1)

          Return a string object containing two hexadecimal digits for
          each byte in the instance.

               >>> bytearray(b'\xf0\xf1\xf2').hex()
               'f0f1f2'

          Added in version 3.5.

          Changed in version 3.8: Similar to *note bytes.hex(): d93,
          ‘bytearray.hex()’ now supports optional 'sep' and
          'bytes_per_sep' parameters to insert separators between bytes
          in the hex output.

Since bytearray objects are sequences of integers (akin to a list), for
a bytearray object 'b', ‘b[0]’ will be an integer, while ‘b[0:1]’ will
be a bytearray object of length 1.  (This contrasts with text strings,
where both indexing and slicing will produce a string of length 1)

The representation of bytearray objects uses the bytes literal format
(‘bytearray(b'...')’) since it is often more useful than e.g.
‘bytearray([46, 46, 46])’.  You can always convert a bytearray object
into a list of integers using ‘list(b)’.


File: python.info,  Node: Bytes and Bytearray Operations,  Next: printf-style Bytes Formatting,  Prev: Bytearray Objects,  Up: Binary Sequence Types — bytes bytearray memoryview

5.4.9.3 Bytes and Bytearray Operations
......................................

Both bytes and bytearray objects support the *note common: 2361.
sequence operations.  They interoperate not just with operands of the
same type, but with any *note bytes-like object: d55.  Due to this
flexibility, they can be freely mixed in operations without causing
errors.  However, the return type of the result may depend on the order
of operands.

     Note: The methods on bytes and bytearray objects don’t accept
     strings as their arguments, just as the methods on strings don’t
     accept bytes as their arguments.  For example, you have to write:

          a = "abc"
          b = a.replace("a", "f")

     and:

          a = b"abc"
          b = a.replace(b"a", b"f")

Some bytes and bytearray operations assume the use of ASCII compatible
binary formats, and hence should be avoided when working with arbitrary
binary data.  These restrictions are covered below.

     Note: Using these ASCII based operations to manipulate binary data
     that is not stored in an ASCII based format may lead to data
     corruption.

The following methods on bytes and bytearray objects can be used with
arbitrary binary data.

 -- Method: bytes.count (sub[, start[, end]])
 -- Method: bytearray.count (sub[, start[, end]])

     Return the number of non-overlapping occurrences of subsequence
     'sub' in the range ['start', 'end'].  Optional arguments 'start'
     and 'end' are interpreted as in slice notation.

     The subsequence to search for may be any *note bytes-like object:
     d55. or an integer in the range 0 to 255.

     If 'sub' is empty, returns the number of empty slices between
     characters which is the length of the bytes object plus one.

     Changed in version 3.3: Also accept an integer in the range 0 to
     255 as the subsequence.

 -- Method: bytes.removeprefix (prefix, /)
 -- Method: bytearray.removeprefix (prefix, /)

     If the binary data starts with the 'prefix' string, return
     ‘bytes[len(prefix):]’.  Otherwise, return a copy of the original
     binary data:

          >>> b'TestHook'.removeprefix(b'Test')
          b'Hook'
          >>> b'BaseTestCase'.removeprefix(b'Test')
          b'BaseTestCase'

     The 'prefix' may be any *note bytes-like object: d55.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

     Added in version 3.9.

 -- Method: bytes.removesuffix (suffix, /)
 -- Method: bytearray.removesuffix (suffix, /)

     If the binary data ends with the 'suffix' string and that 'suffix'
     is not empty, return ‘bytes[:-len(suffix)]’.  Otherwise, return a
     copy of the original binary data:

          >>> b'MiscTests'.removesuffix(b'Tests')
          b'Misc'
          >>> b'TmpDirMixin'.removesuffix(b'Tests')
          b'TmpDirMixin'

     The 'suffix' may be any *note bytes-like object: d55.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

     Added in version 3.9.

 -- Method: bytes.decode (encoding='utf-8', errors='strict')
 -- Method: bytearray.decode (encoding='utf-8', errors='strict')

     Return the bytes decoded to a *note str: 44f.

     'encoding' defaults to ‘'utf-8'’; see *note Standard Encodings:
     de7. for possible values.

     'errors' controls how decoding errors are handled.  If ‘'strict'’
     (the default), a *note UnicodeError: 12eb. exception is raised.
     Other possible values are ‘'ignore'’, ‘'replace'’, and any other
     name registered via *note codecs.register_error(): 14ea.  See *note
     Error Handlers: 1915. for details.

     For performance reasons, the value of 'errors' is not checked for
     validity unless a decoding error actually occurs, *note Python
     Development Mode: 1f8. is enabled or a *note debug build: 1f9. is
     used.

          Note: Passing the 'encoding' argument to *note str: 44f.
          allows decoding any *note bytes-like object: d55. directly,
          without needing to make a temporary ‘bytes’ or ‘bytearray’
          object.

     Changed in version 3.1: Added support for keyword arguments.

     Changed in version 3.9: The value of the 'errors' argument is now
     checked in *note Python Development Mode: 1f8. and in *note debug
     mode: 1f9.

 -- Method: bytes.endswith (suffix[, start[, end]])
 -- Method: bytearray.endswith (suffix[, start[, end]])

     Return ‘True’ if the binary data ends with the specified 'suffix',
     otherwise return ‘False’.  'suffix' can also be a tuple of suffixes
     to look for.  With optional 'start', test beginning at that
     position.  With optional 'end', stop comparing at that position.

     The suffix(es) to search for may be any *note bytes-like object:
     d55.

 -- Method: bytes.find (sub[, start[, end]])
 -- Method: bytearray.find (sub[, start[, end]])

     Return the lowest index in the data where the subsequence 'sub' is
     found, such that 'sub' is contained in the slice ‘s[start:end]’.
     Optional arguments 'start' and 'end' are interpreted as in slice
     notation.  Return ‘-1’ if 'sub' is not found.

     The subsequence to search for may be any *note bytes-like object:
     d55. or an integer in the range 0 to 255.

          Note: The ‘find()’ method should be used only if you need to
          know the position of 'sub'.  To check if 'sub' is a substring
          or not, use the *note in: 2f4. operator:

               >>> b'Py' in b'Python'
               True

     Changed in version 3.3: Also accept an integer in the range 0 to
     255 as the subsequence.

 -- Method: bytes.index (sub[, start[, end]])
 -- Method: bytearray.index (sub[, start[, end]])

     Like *note find(): 1979, but raise *note ValueError: 202. when the
     subsequence is not found.

     The subsequence to search for may be any *note bytes-like object:
     d55. or an integer in the range 0 to 255.

     Changed in version 3.3: Also accept an integer in the range 0 to
     255 as the subsequence.

 -- Method: bytes.join (iterable, /)
 -- Method: bytearray.join (iterable, /)

     Return a bytes or bytearray object which is the concatenation of
     the binary data sequences in 'iterable'.  A *note TypeError: 2c3.
     will be raised if there are any values in 'iterable' that are not
     *note bytes-like objects: d55, including *note str: 44f. objects.
     The separator between elements is the contents of the bytes or
     bytearray object providing this method.

 -- Method: static bytes.maketrans (from, to, /)
 -- Method: static bytearray.maketrans (from, to, /)

     This static method returns a translation table usable for *note
     bytes.translate(): 239c. that will map each character in 'from'
     into the character at the same position in 'to'; 'from' and 'to'
     must both be *note bytes-like objects: d55. and have the same
     length.

     Added in version 3.1.

 -- Method: bytes.partition (sep, /)
 -- Method: bytearray.partition (sep, /)

     Split the sequence at the first occurrence of 'sep', and return a
     3-tuple containing the part before the separator, the separator
     itself or its bytearray copy, and the part after the separator.  If
     the separator is not found, return a 3-tuple containing a copy of
     the original sequence, followed by two empty bytes or bytearray
     objects.

     The separator to search for may be any *note bytes-like object:
     d55.

 -- Method: bytes.replace (old, new, count=-1, /)
 -- Method: bytearray.replace (old, new, count=-1, /)

     Return a copy of the sequence with all occurrences of subsequence
     'old' replaced by 'new'.  If the optional argument 'count' is
     given, only the first 'count' occurrences are replaced.

     The subsequence to search for and its replacement may be any *note
     bytes-like object: d55.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.rfind (sub[, start[, end]])
 -- Method: bytearray.rfind (sub[, start[, end]])

     Return the highest index in the sequence where the subsequence
     'sub' is found, such that 'sub' is contained within ‘s[start:end]’.
     Optional arguments 'start' and 'end' are interpreted as in slice
     notation.  Return ‘-1’ on failure.

     The subsequence to search for may be any *note bytes-like object:
     d55. or an integer in the range 0 to 255.

     Changed in version 3.3: Also accept an integer in the range 0 to
     255 as the subsequence.

 -- Method: bytes.rindex (sub[, start[, end]])
 -- Method: bytearray.rindex (sub[, start[, end]])

     Like *note rfind(): 197a. but raises *note ValueError: 202. when
     the subsequence 'sub' is not found.

     The subsequence to search for may be any *note bytes-like object:
     d55. or an integer in the range 0 to 255.

     Changed in version 3.3: Also accept an integer in the range 0 to
     255 as the subsequence.

 -- Method: bytes.rpartition (sep, /)
 -- Method: bytearray.rpartition (sep, /)

     Split the sequence at the last occurrence of 'sep', and return a
     3-tuple containing the part before the separator, the separator
     itself or its bytearray copy, and the part after the separator.  If
     the separator is not found, return a 3-tuple containing two empty
     bytes or bytearray objects, followed by a copy of the original
     sequence.

     The separator to search for may be any *note bytes-like object:
     d55.

 -- Method: bytes.startswith (prefix[, start[, end]])
 -- Method: bytearray.startswith (prefix[, start[, end]])

     Return ‘True’ if the binary data starts with the specified
     'prefix', otherwise return ‘False’.  'prefix' can also be a tuple
     of prefixes to look for.  With optional 'start', test beginning at
     that position.  With optional 'end', stop comparing at that
     position.

     The prefix(es) to search for may be any *note bytes-like object:
     d55.

 -- Method: bytes.translate (table, /, delete=b'')
 -- Method: bytearray.translate (table, /, delete=b'')

     Return a copy of the bytes or bytearray object where all bytes
     occurring in the optional argument 'delete' are removed, and the
     remaining bytes have been mapped through the given translation
     table, which must be a bytes object of length 256.

     You can use the *note bytes.maketrans(): 12bb. method to create a
     translation table.

     Set the 'table' argument to ‘None’ for translations that only
     delete characters:

          >>> b'read this short text'.translate(None, b'aeiou')
          b'rd ths shrt txt'

     Changed in version 3.6: 'delete' is now supported as a keyword
     argument.

The following methods on bytes and bytearray objects have default
behaviours that assume the use of ASCII compatible binary formats, but
can still be used with arbitrary binary data by passing appropriate
arguments.  Note that all of the bytearray methods in this section do
'not' operate in place, and instead produce new objects.

 -- Method: bytes.center (width, fillbyte=b' ', /)
 -- Method: bytearray.center (width, fillbyte=b' ', /)

     Return a copy of the object centered in a sequence of length
     'width'.  Padding is done using the specified 'fillbyte' (default
     is an ASCII space).  For *note bytes: 1c2. objects, the original
     sequence is returned if 'width' is less than or equal to ‘len(s)’.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.ljust (width, fillbyte=b' ', /)
 -- Method: bytearray.ljust (width, fillbyte=b' ', /)

     Return a copy of the object left justified in a sequence of length
     'width'.  Padding is done using the specified 'fillbyte' (default
     is an ASCII space).  For *note bytes: 1c2. objects, the original
     sequence is returned if 'width' is less than or equal to ‘len(s)’.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.lstrip (bytes=None, /)
 -- Method: bytearray.lstrip (bytes=None, /)

     Return a copy of the sequence with specified leading bytes removed.
     The 'bytes' argument is a binary sequence specifying the set of
     byte values to be removed.  If omitted or ‘None’, the 'bytes'
     argument defaults to removing ASCII whitespace.  The 'bytes'
     argument is not a prefix; rather, all combinations of its values
     are stripped:

          >>> b'   spacious   '.lstrip()
          b'spacious   '
          >>> b'www.example.com'.lstrip(b'cmowz.')
          b'example.com'

     The binary sequence of byte values to remove may be any *note
     bytes-like object: d55.  See *note removeprefix(): 2394. for a
     method that will remove a single prefix string rather than all of a
     set of characters.  For example:

          >>> b'Arthur: three!'.lstrip(b'Arthur: ')
          b'ee!'
          >>> b'Arthur: three!'.removeprefix(b'Arthur: ')
          b'three!'

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.rjust (width, fillbyte=b' ', /)
 -- Method: bytearray.rjust (width, fillbyte=b' ', /)

     Return a copy of the object right justified in a sequence of length
     'width'.  Padding is done using the specified 'fillbyte' (default
     is an ASCII space).  For *note bytes: 1c2. objects, the original
     sequence is returned if 'width' is less than or equal to ‘len(s)’.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.rsplit (sep=None, maxsplit=-1)
 -- Method: bytearray.rsplit (sep=None, maxsplit=-1)

     Split the binary sequence into subsequences of the same type, using
     'sep' as the delimiter string.  If 'maxsplit' is given, at most
     'maxsplit' splits are done, the 'rightmost' ones.  If 'sep' is not
     specified or ‘None’, any subsequence consisting solely of ASCII
     whitespace is a separator.  Except for splitting from the right,
     ‘rsplit()’ behaves like *note split(): 15e4. which is described in
     detail below.

 -- Method: bytes.rstrip (bytes=None, /)
 -- Method: bytearray.rstrip (bytes=None, /)

     Return a copy of the sequence with specified trailing bytes
     removed.  The 'bytes' argument is a binary sequence specifying the
     set of byte values to be removed.  If omitted or ‘None’, the
     'bytes' argument defaults to removing ASCII whitespace.  The
     'bytes' argument is not a suffix; rather, all combinations of its
     values are stripped:

          >>> b'   spacious   '.rstrip()
          b'   spacious'
          >>> b'mississippi'.rstrip(b'ipz')
          b'mississ'

     The binary sequence of byte values to remove may be any *note
     bytes-like object: d55.  See *note removesuffix(): 2396. for a
     method that will remove a single suffix string rather than all of a
     set of characters.  For example:

          >>> b'Monty Python'.rstrip(b' Python')
          b'M'
          >>> b'Monty Python'.removesuffix(b' Python')
          b'Monty'

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.split (sep=None, maxsplit=-1)
 -- Method: bytearray.split (sep=None, maxsplit=-1)

     Split the binary sequence into subsequences of the same type, using
     'sep' as the delimiter string.  If 'maxsplit' is given and
     non-negative, at most 'maxsplit' splits are done (thus, the list
     will have at most ‘maxsplit+1’ elements).  If 'maxsplit' is not
     specified or is ‘-1’, then there is no limit on the number of
     splits (all possible splits are made).

     If 'sep' is given, consecutive delimiters are not grouped together
     and are deemed to delimit empty subsequences (for example,
     ‘b'1,,2'.split(b',')’ returns ‘[b'1', b'', b'2']’).  The 'sep'
     argument may consist of a multibyte sequence as a single delimiter.
     Splitting an empty sequence with a specified separator returns
     ‘[b'']’ or ‘[bytearray(b'')]’ depending on the type of object being
     split.  The 'sep' argument may be any *note bytes-like object: d55.

     For example:

          >>> b'1,2,3'.split(b',')
          [b'1', b'2', b'3']
          >>> b'1,2,3'.split(b',', maxsplit=1)
          [b'1', b'2,3']
          >>> b'1,2,,3,'.split(b',')
          [b'1', b'2', b'', b'3', b'']
          >>> b'1<>2<>3<4'.split(b'<>')
          [b'1', b'2', b'3<4']

     If 'sep' is not specified or is ‘None’, a different splitting
     algorithm is applied: runs of consecutive ASCII whitespace are
     regarded as a single separator, and the result will contain no
     empty strings at the start or end if the sequence has leading or
     trailing whitespace.  Consequently, splitting an empty sequence or
     a sequence consisting solely of ASCII whitespace without a
     specified separator returns ‘[]’.

     For example:

          >>> b'1 2 3'.split()
          [b'1', b'2', b'3']
          >>> b'1 2 3'.split(maxsplit=1)
          [b'1', b'2 3']
          >>> b'   1   2   3   '.split()
          [b'1', b'2', b'3']

 -- Method: bytes.strip (bytes=None, /)
 -- Method: bytearray.strip (bytes=None, /)

     Return a copy of the sequence with specified leading and trailing
     bytes removed.  The 'bytes' argument is a binary sequence
     specifying the set of byte values to be removed.  If omitted or
     ‘None’, the 'bytes' argument defaults to removing ASCII whitespace.
     The 'bytes' argument is not a prefix or suffix; rather, all
     combinations of its values are stripped:

          >>> b'   spacious   '.strip()
          b'spacious'
          >>> b'www.example.com'.strip(b'cmowz.')
          b'example'

     The binary sequence of byte values to remove may be any *note
     bytes-like object: d55.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

The following methods on bytes and bytearray objects assume the use of
ASCII compatible binary formats and should not be applied to arbitrary
binary data.  Note that all of the bytearray methods in this section do
'not' operate in place, and instead produce new objects.

 -- Method: bytes.capitalize ()
 -- Method: bytearray.capitalize ()

     Return a copy of the sequence with each byte interpreted as an
     ASCII character, and the first byte capitalized and the rest
     lowercased.  Non-ASCII byte values are passed through unchanged.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.expandtabs (tabsize=8)
 -- Method: bytearray.expandtabs (tabsize=8)

     Return a copy of the sequence where all ASCII tab characters are
     replaced by one or more ASCII spaces, depending on the current
     column and the given tab size.  Tab positions occur every 'tabsize'
     bytes (default is 8, giving tab positions at columns 0, 8, 16 and
     so on).  To expand the sequence, the current column is set to zero
     and the sequence is examined byte by byte.  If the byte is an ASCII
     tab character (‘b'\t'’), one or more space characters are inserted
     in the result until the current column is equal to the next tab
     position.  (The tab character itself is not copied.)  If the
     current byte is an ASCII newline (‘b'\n'’) or carriage return
     (‘b'\r'’), it is copied and the current column is reset to zero.
     Any other byte value is copied unchanged and the current column is
     incremented by one regardless of how the byte value is represented
     when printed:

          >>> b'01\t012\t0123\t01234'.expandtabs()
          b'01      012     0123    01234'
          >>> b'01\t012\t0123\t01234'.expandtabs(4)
          b'01  012 0123    01234'

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.isalnum ()
 -- Method: bytearray.isalnum ()

     Return ‘True’ if all bytes in the sequence are alphabetical ASCII
     characters or ASCII decimal digits and the sequence is not empty,
     ‘False’ otherwise.  Alphabetic ASCII characters are those byte
     values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'’.  ASCII
     decimal digits are those byte values in the sequence
     ‘b'0123456789'’.

     For example:

          >>> b'ABCabc1'.isalnum()
          True
          >>> b'ABC abc1'.isalnum()
          False

 -- Method: bytes.isalpha ()
 -- Method: bytearray.isalpha ()

     Return ‘True’ if all bytes in the sequence are alphabetic ASCII
     characters and the sequence is not empty, ‘False’ otherwise.
     Alphabetic ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

     For example:

          >>> b'ABCabc'.isalpha()
          True
          >>> b'ABCabc1'.isalpha()
          False

 -- Method: bytes.isascii ()
 -- Method: bytearray.isascii ()

     Return ‘True’ if the sequence is empty or all bytes in the sequence
     are ASCII, ‘False’ otherwise.  ASCII bytes are in the range 0-0x7F.

     Added in version 3.7.

 -- Method: bytes.isdigit ()
 -- Method: bytearray.isdigit ()

     Return ‘True’ if all bytes in the sequence are ASCII decimal digits
     and the sequence is not empty, ‘False’ otherwise.  ASCII decimal
     digits are those byte values in the sequence ‘b'0123456789'’.

     For example:

          >>> b'1234'.isdigit()
          True
          >>> b'1.23'.isdigit()
          False

 -- Method: bytes.islower ()
 -- Method: bytearray.islower ()

     Return ‘True’ if there is at least one lowercase ASCII character in
     the sequence and no uppercase ASCII characters, ‘False’ otherwise.

     For example:

          >>> b'hello world'.islower()
          True
          >>> b'Hello world'.islower()
          False

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

 -- Method: bytes.isspace ()
 -- Method: bytearray.isspace ()

     Return ‘True’ if all bytes in the sequence are ASCII whitespace and
     the sequence is not empty, ‘False’ otherwise.  ASCII whitespace
     characters are those byte values in the sequence ‘b' \t\n\r\x0b\f'’
     (space, tab, newline, carriage return, vertical tab, form feed).

 -- Method: bytes.istitle ()
 -- Method: bytearray.istitle ()

     Return ‘True’ if the sequence is ASCII titlecase and the sequence
     is not empty, ‘False’ otherwise.  See *note bytes.title(): 23c5.
     for more details on the definition of “titlecase”.

     For example:

          >>> b'Hello World'.istitle()
          True
          >>> b'Hello world'.istitle()
          False

 -- Method: bytes.isupper ()
 -- Method: bytearray.isupper ()

     Return ‘True’ if there is at least one uppercase alphabetic ASCII
     character in the sequence and no lowercase ASCII characters,
     ‘False’ otherwise.

     For example:

          >>> b'HELLO WORLD'.isupper()
          True
          >>> b'Hello world'.isupper()
          False

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

 -- Method: bytes.lower ()
 -- Method: bytearray.lower ()

     Return a copy of the sequence with all the uppercase ASCII
     characters converted to their corresponding lowercase counterpart.

     For example:

          >>> b'Hello World'.lower()
          b'hello world'

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.splitlines (keepends=False)
 -- Method: bytearray.splitlines (keepends=False)

     Return a list of the lines in the binary sequence, breaking at
     ASCII line boundaries.  This method uses the *note universal
     newlines: d62. approach to splitting lines.  Line breaks are not
     included in the resulting list unless 'keepends' is given and true.

     For example:

          >>> b'ab c\n\nde fg\rkl\r\n'.splitlines()
          [b'ab c', b'', b'de fg', b'kl']
          >>> b'ab c\n\nde fg\rkl\r\n'.splitlines(keepends=True)
          [b'ab c\n', b'\n', b'de fg\r', b'kl\r\n']

     Unlike *note split(): 23b0. when a delimiter string 'sep' is given,
     this method returns an empty list for the empty string, and a
     terminal line break does not result in an extra line:

          >>> b"".split(b'\n'), b"Two lines\n".split(b'\n')
          ([b''], [b'Two lines', b''])
          >>> b"".splitlines(), b"One line\n".splitlines()
          ([], [b'One line'])

 -- Method: bytes.swapcase ()
 -- Method: bytearray.swapcase ()

     Return a copy of the sequence with all the lowercase ASCII
     characters converted to their corresponding uppercase counterpart
     and vice-versa.

     For example:

          >>> b'Hello World'.swapcase()
          b'hELLO wORLD'

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

     Unlike *note str.swapcase(): 2388, it is always the case that
     ‘bin.swapcase().swapcase() == bin’ for the binary versions.  Case
     conversions are symmetrical in ASCII, even though that is not
     generally true for arbitrary Unicode code points.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.title ()
 -- Method: bytearray.title ()

     Return a titlecased version of the binary sequence where words
     start with an uppercase ASCII character and the remaining
     characters are lowercase.  Uncased byte values are left unmodified.

     For example:

          >>> b'Hello world'.title()
          b'Hello World'

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.
     All other byte values are uncased.

     The algorithm uses a simple language-independent definition of a
     word as groups of consecutive letters.  The definition works in
     many contexts but it means that apostrophes in contractions and
     possessives form word boundaries, which may not be the desired
     result:

          >>> b"they're bill's friends from the UK".title()
          b"They'Re Bill'S Friends From The Uk"

     A workaround for apostrophes can be constructed using regular
     expressions:

          >>> import re
          >>> def titlecase(s):
          ...     return re.sub(rb"[A-Za-z]+('[A-Za-z]+)?",
          ...                   lambda mo: mo.group(0)[0:1].upper() +
          ...                              mo.group(0)[1:].lower(),
          ...                   s)
          ...
          >>> titlecase(b"they're bill's friends.")
          b"They're Bill's Friends."

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.upper ()
 -- Method: bytearray.upper ()

     Return a copy of the sequence with all the lowercase ASCII
     characters converted to their corresponding uppercase counterpart.

     For example:

          >>> b'Hello World'.upper()
          b'HELLO WORLD'

     Lowercase ASCII characters are those byte values in the sequence
     ‘b'abcdefghijklmnopqrstuvwxyz'’.  Uppercase ASCII characters are
     those byte values in the sequence ‘b'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.

 -- Method: bytes.zfill (width, /)
 -- Method: bytearray.zfill (width, /)

     Return a copy of the sequence left filled with ASCII ‘b'0'’ digits
     to make a sequence of length 'width'.  A leading sign prefix
     (‘b'+'’/ ‘b'-'’) is handled by inserting the padding 'after' the
     sign character rather than before.  For *note bytes: 1c2. objects,
     the original sequence is returned if 'width' is less than or equal
     to ‘len(seq)’.

     For example:

          >>> b"42".zfill(5)
          b'00042'
          >>> b"-42".zfill(5)
          b'-0042'

          Note: The bytearray version of this method does 'not' operate
          in place - it always produces a new object, even if no changes
          were made.


File: python.info,  Node: printf-style Bytes Formatting,  Next: Memory Views,  Prev: Bytes and Bytearray Operations,  Up: Binary Sequence Types — bytes bytearray memoryview

5.4.9.4 ‘printf’-style Bytes Formatting
.......................................

     Note: The formatting operations described here exhibit a variety of
     quirks that lead to a number of common errors (such as failing to
     display tuples and dictionaries correctly).  If the value being
     printed may be a tuple or dictionary, wrap it in a tuple.

Bytes objects (‘bytes’/‘bytearray’) have one unique built-in operation:
the ‘%’ operator (modulo).  This is also known as the bytes 'formatting'
or 'interpolation' operator.  Given ‘format % values’ (where 'format' is
a bytes object), ‘%’ conversion specifications in 'format' are replaced
with zero or more elements of 'values'.  The effect is similar to using
the ‘sprintf()’ in the C language.

If 'format' requires a single argument, 'values' may be a single
non-tuple object.  (1)  Otherwise, 'values' must be a tuple with exactly
the number of items specified by the format bytes object, or a single
mapping object (for example, a dictionary).

A conversion specifier contains two or more characters and has the
following components, which must occur in this order:

  1. The ‘'%'’ character, which marks the start of the specifier.

  2. Mapping key (optional), consisting of a parenthesised sequence of
     characters (for example, ‘(somename)’).

  3. Conversion flags (optional), which affect the result of some
     conversion types.

  4. Minimum field width (optional).  If specified as an ‘'*'’
     (asterisk), the actual width is read from the next element of the
     tuple in 'values', and the object to convert comes after the
     minimum field width and optional precision.

  5. Precision (optional), given as a ‘'.'’ (dot) followed by the
     precision.  If specified as ‘'*'’ (an asterisk), the actual
     precision is read from the next element of the tuple in 'values',
     and the value to convert comes after the precision.

  6. Length modifier (optional).

  7. Conversion type.

When the right argument is a dictionary (or other mapping type), then
the formats in the bytes object 'must' include a parenthesised mapping
key into that dictionary inserted immediately after the ‘'%'’ character.
The mapping key selects the value to be formatted from the mapping.  For
example:

     >>> print(b'%(language)s has %(number)03d quote types.' %
     ...       {b'language': b"Python", b"number": 2})
     b'Python has 002 quote types.'

In this case no ‘*’ specifiers may occur in a format (since they require
a sequential parameter list).

The conversion flag characters are:

Flag          Meaning
              
----------------------------------------------------------------------------------------
              
‘'#'’         The value conversion will use the “alternate form” (where defined
              below).
              
              
‘'0'’         The conversion will be zero padded for numeric values.
              
              
‘'-'’         The converted value is left adjusted (overrides the ‘'0'’ conversion if
              both are given).
              
              
‘' '’         (a space) A blank should be left before a positive number (or empty
              string) produced by a signed conversion.
              
              
‘'+'’         A sign character (‘'+'’ or ‘'-'’) will precede the conversion
              (overrides a “space” flag).
              

A length modifier (‘h’, ‘l’, or ‘L’) may be present, but is ignored as
it is not necessary for Python – so e.g.  ‘%ld’ is identical to ‘%d’.

The conversion types are:

Conversion       Meaning                                                   Notes
                                                                           
---------------------------------------------------------------------------------------
                                                                           
‘'d'’            Signed integer decimal.
                 
                                                                           
‘'i'’            Signed integer decimal.
                 
                                                                           
‘'o'’            Signed octal value.                                       (1)
                                                                           
                                                                           
‘'u'’            Obsolete type – it is identical to ‘'d'’.                 (8)
                                                                           
                                                                           
‘'x'’            Signed hexadecimal (lowercase).                           (2)
                                                                           
                                                                           
‘'X'’            Signed hexadecimal (uppercase).                           (2)
                                                                           
                                                                           
‘'e'’            Floating-point exponential format (lowercase).            (3)
                                                                           
                                                                           
‘'E'’            Floating-point exponential format (uppercase).            (3)
                                                                           
                                                                           
‘'f'’            Floating-point decimal format.                            (3)
                                                                           
                                                                           
‘'F'’            Floating-point decimal format.                            (3)
                                                                           
                                                                           
‘'g'’            Floating-point format.  Uses lowercase exponential        (4)
                 format if exponent is less than -4 or not less than       
                 precision, decimal format otherwise.
                 
                                                                           
‘'G'’            Floating-point format.  Uses uppercase exponential        (4)
                 format if exponent is less than -4 or not less than       
                 precision, decimal format otherwise.
                 
                                                                           
‘'c'’            Single byte (accepts integer or single byte objects).
                 
                                                                           
‘'b'’            Bytes (any object that follows the                        (5)
                 *note buffer protocol: 2e8. or has                        
                 *note __bytes__(): 5eb.).
                 
                                                                           
‘'s'’            ‘'s'’ is an alias for ‘'b'’ and should only be used for   (6)
                 Python2/3 code bases.                                     
                 
                                                                           
‘'a'’            Bytes (converts any Python object using                   (5)
                 ‘repr(obj).encode('ascii', 'backslashreplace')’).         
                 
                                                                           
‘'r'’            ‘'r'’ is an alias for ‘'a'’ and should only be used for   (7)
                 Python2/3 code bases.                                     
                 
                                                                           
‘'%'’            No argument is converted, results in a ‘'%'’ character
                 in the result.
                 

Notes:

  1. The alternate form causes a leading octal specifier (‘'0o'’) to be
     inserted before the first digit.

  2. The alternate form causes a leading ‘'0x'’ or ‘'0X'’ (depending on
     whether the ‘'x'’ or ‘'X'’ format was used) to be inserted before
     the first digit.

  3. The alternate form causes the result to always contain a decimal
     point, even if no digits follow it.

     The precision determines the number of digits after the decimal
     point and defaults to 6.

  4. The alternate form causes the result to always contain a decimal
     point, and trailing zeroes are not removed as they would otherwise
     be.

     The precision determines the number of significant digits before
     and after the decimal point and defaults to 6.

  5. If precision is ‘N’, the output is truncated to ‘N’ characters.

  6. ‘b'%s'’ is deprecated, but will not be removed during the 3.x
     series.

  7. ‘b'%r'’ is deprecated, but will not be removed during the 3.x
     series.

  8. See PEP 237(2).

     Note: The bytearray version of this method does 'not' operate in
     place - it always produces a new object, even if no changes were
     made.

See also
........

PEP 461(3) - Adding % formatting to bytes and bytearray

Added in version 3.5.

   ---------- Footnotes ----------

   (1) To format only a tuple you should therefore provide a singleton
tuple whose only element is the tuple to be formatted.

   (2) https://peps.python.org/pep-0237/

   (3) https://peps.python.org/pep-0461/


File: python.info,  Node: Memory Views,  Prev: printf-style Bytes Formatting,  Up: Binary Sequence Types — bytes bytearray memoryview

5.4.9.5 Memory Views
....................

*note memoryview: 2eb. objects allow Python code to access the internal
data of an object that supports the *note buffer protocol: 2e8. without
copying.

 -- Class: memoryview (object)

     Create a ‘memoryview’ that references 'object'.  'object' must
     support the buffer protocol.  Built-in objects that support the
     buffer protocol include *note bytes: 1c2. and *note bytearray: 2ea.

     A ‘memoryview’ has the notion of an 'element', which is the atomic
     memory unit handled by the originating 'object'.  For many simple
     types such as *note bytes: 1c2. and *note bytearray: 2ea, an
     element is a single byte, but other types such as *note
     array.array: 1a0. may have bigger elements.

     ‘len(view)’ is equal to the length of *note tolist: 23d5, which is
     the nested list representation of the view.  If ‘view.ndim = 1’,
     this is equal to the number of elements in the view.

     Changed in version 3.12: If ‘view.ndim == 0’, ‘len(view)’ now
     raises *note TypeError: 2c3. instead of returning 1.

     The *note itemsize: 23d6. attribute will give you the number of
     bytes in a single element.

     A ‘memoryview’ supports slicing and indexing to expose its data.
     One-dimensional slicing will result in a subview:

          >>> v = memoryview(b'abcefg')
          >>> v[1]
          98
          >>> v[-1]
          103
          >>> v[1:4]
          <memory at 0x7f3ddc9f4350>
          >>> bytes(v[1:4])
          b'bce'

     If *note format: 23d7. is one of the native format specifiers from
     the *note struct: d5. module, indexing with an integer or a tuple
     of integers is also supported and returns a single 'element' with
     the correct type.  One-dimensional memoryviews can be indexed with
     an integer or a one-integer tuple.  Multi-dimensional memoryviews
     can be indexed with tuples of exactly 'ndim' integers where 'ndim'
     is the number of dimensions.  Zero-dimensional memoryviews can be
     indexed with the empty tuple.

     Here is an example with a non-byte format:

          >>> import array
          >>> a = array.array('l', [-11111111, 22222222, -33333333, 44444444])
          >>> m = memoryview(a)
          >>> m[0]
          -11111111
          >>> m[-1]
          44444444
          >>> m[::2].tolist()
          [-11111111, -33333333]

     If the underlying object is writable, the memoryview supports
     one-dimensional slice assignment.  Resizing is not allowed:

          >>> data = bytearray(b'abcefg')
          >>> v = memoryview(data)
          >>> v.readonly
          False
          >>> v[0] = ord(b'z')
          >>> data
          bytearray(b'zbcefg')
          >>> v[1:4] = b'123'
          >>> data
          bytearray(b'z123fg')
          >>> v[2:3] = b'spam'
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
          ValueError: memoryview assignment: lvalue and rvalue have different structures
          >>> v[2:6] = b'spam'
          >>> data
          bytearray(b'z1spam')

     One-dimensional memoryviews of *note hashable: 613. (read-only)
     types with formats ‘B’, ‘b’ or ‘c’ are also hashable.  The hash is
     defined as ‘hash(m) == hash(m.tobytes())’:

          >>> v = memoryview(b'abcefg')
          >>> hash(v) == hash(b'abcefg')
          True
          >>> hash(v[2:4]) == hash(b'ce')
          True
          >>> hash(v[::-2]) == hash(b'abcefg'[::-2])
          True

     Changed in version 3.3: One-dimensional memoryviews can now be
     sliced.  One-dimensional memoryviews with formats ‘B’, ‘b’ or ‘c’
     are now *note hashable: 613.

     Changed in version 3.4: memoryview is now registered automatically
     with *note collections.abc.Sequence: 1209.

     Changed in version 3.5: memoryviews can now be indexed with tuple
     of integers.

     ‘memoryview’ has several methods:

      -- Method: __eq__ (exporter)

          A memoryview and a PEP 3118(1) exporter are equal if their
          shapes are equivalent and if all corresponding values are
          equal when the operands’ respective format codes are
          interpreted using *note struct: d5. syntax.

          For the subset of *note struct: d5. format strings currently
          supported by *note tolist(): 23d5, ‘v’ and ‘w’ are equal if
          ‘v.tolist() == w.tolist()’:

               >>> import array
               >>> a = array.array('I', [1, 2, 3, 4, 5])
               >>> b = array.array('d', [1.0, 2.0, 3.0, 4.0, 5.0])
               >>> c = array.array('b', [5, 3, 1])
               >>> x = memoryview(a)
               >>> y = memoryview(b)
               >>> x == a == y == b
               True
               >>> x.tolist() == a.tolist() == y.tolist() == b.tolist()
               True
               >>> z = y[::-2]
               >>> z == c
               True
               >>> z.tolist() == c.tolist()
               True

          If either format string is not supported by the *note struct:
          d5. module, then the objects will always compare as unequal
          (even if the format strings and buffer contents are
          identical):

               >>> from ctypes import BigEndianStructure, c_long
               >>> class BEPoint(BigEndianStructure):
               ...     _fields_ = [("x", c_long), ("y", c_long)]
               ...
               >>> point = BEPoint(100, 200)
               >>> a = memoryview(point)
               >>> b = memoryview(point)
               >>> a == point
               False
               >>> a == b
               False

          Note that, as with floating-point numbers, ‘v is w’ does 'not'
          imply ‘v == w’ for memoryview objects.

          Changed in version 3.3: Previous versions compared the raw
          memory disregarding the item format and the logical array
          structure.

      -- Method: tobytes (order='C')

          Return the data in the buffer as a bytestring.  This is
          equivalent to calling the *note bytes: 1c2. constructor on the
          memoryview.

               >>> m = memoryview(b"abc")
               >>> m.tobytes()
               b'abc'
               >>> bytes(m)
               b'abc'

          For non-contiguous arrays the result is equal to the flattened
          list representation with all elements converted to bytes.
          ‘tobytes()’ supports all format strings, including those that
          are not in *note struct: d5. module syntax.

          Added in version 3.8: 'order' can be {‘C’, ‘F’, ‘A’}.  When
          'order' is ‘C’ or ‘F’, the data of the original array is
          converted to C or Fortran order.  For contiguous views, ‘A’
          returns an exact copy of the physical memory.  In particular,
          in-memory Fortran order is preserved.  For non-contiguous
          views, the data is converted to C first.  'order=None' is the
          same as 'order=’C’'.

      -- Method: hex (*, bytes_per_sep=1)

      -- Method: hex (sep, bytes_per_sep=1)

          Return a string object containing two hexadecimal digits for
          each byte in the buffer.

               >>> m = memoryview(b"abc")
               >>> m.hex()
               '616263'

          Added in version 3.5.

          Changed in version 3.8: Similar to *note bytes.hex(): d93,
          ‘memoryview.hex()’ now supports optional 'sep' and
          'bytes_per_sep' parameters to insert separators between bytes
          in the hex output.

      -- Method: tolist ()

          Return the data in the buffer as a list of elements.

               >>> memoryview(b'abc').tolist()
               [97, 98, 99]
               >>> import array
               >>> a = array.array('d', [1.1, 2.2, 3.3])
               >>> m = memoryview(a)
               >>> m.tolist()
               [1.1, 2.2, 3.3]

          Changed in version 3.3: ‘tolist()’ now supports all single
          character native formats in *note struct: d5. module syntax as
          well as multi-dimensional representations.

      -- Method: toreadonly ()

          Return a readonly version of the memoryview object.  The
          original memoryview object is unchanged.

               >>> m = memoryview(bytearray(b'abc'))
               >>> mm = m.toreadonly()
               >>> mm.tolist()
               [97, 98, 99]
               >>> mm[0] = 42
               Traceback (most recent call last):
                 File "<stdin>", line 1, in <module>
               TypeError: cannot modify read-only memory
               >>> m[0] = 43
               >>> mm.tolist()
               [43, 98, 99]

          Added in version 3.8.

      -- Method: release ()

          Release the underlying buffer exposed by the memoryview
          object.  Many objects take special actions when a view is held
          on them (for example, a *note bytearray: 2ea. would
          temporarily forbid resizing); therefore, calling release() is
          handy to remove these restrictions (and free any dangling
          resources) as soon as possible.

          After this method has been called, any further operation on
          the view raises a *note ValueError: 202. (except ‘release()’
          itself which can be called multiple times):

               >>> m = memoryview(b'abc')
               >>> m.release()
               >>> m[0]
               Traceback (most recent call last):
                 File "<stdin>", line 1, in <module>
               ValueError: operation forbidden on released memoryview object

          The context management protocol can be used for a similar
          effect, using the ‘with’ statement:

               >>> with memoryview(b'abc') as m:
               ...     m[0]
               ...
               97
               >>> m[0]
               Traceback (most recent call last):
                 File "<stdin>", line 1, in <module>
               ValueError: operation forbidden on released memoryview object

          Added in version 3.2.

      -- Method: cast (format, /)

      -- Method: cast (format, shape, /)

          Cast a memoryview to a new format or shape.  'shape' defaults
          to ‘[byte_length//new_itemsize]’, which means that the result
          view will be one-dimensional.  The return value is a new
          memoryview, but the buffer itself is not copied.  Supported
          casts are 1D -> C-*note contiguous: 23dc. and C-contiguous ->
          1D.

          The destination format is restricted to a single element
          native format in *note struct: d5. syntax.  One of the formats
          must be a byte format (‘B’, ‘b’ or ‘c’).  The byte length of
          the result must be the same as the original length.  Note that
          all byte lengths may depend on the operating system.

          Cast 1D/long to 1D/unsigned bytes:

               >>> import array
               >>> a = array.array('l', [1,2,3])
               >>> x = memoryview(a)
               >>> x.format
               'l'
               >>> x.itemsize
               8
               >>> len(x)
               3
               >>> x.nbytes
               24
               >>> y = x.cast('B')
               >>> y.format
               'B'
               >>> y.itemsize
               1
               >>> len(y)
               24
               >>> y.nbytes
               24

          Cast 1D/unsigned bytes to 1D/char:

               >>> b = bytearray(b'zyz')
               >>> x = memoryview(b)
               >>> x[0] = b'a'
               Traceback (most recent call last):
                 ...
               TypeError: memoryview: invalid type for format 'B'
               >>> y = x.cast('c')
               >>> y[0] = b'a'
               >>> b
               bytearray(b'ayz')

          Cast 1D/bytes to 3D/ints to 1D/signed char:

               >>> import struct
               >>> buf = struct.pack("i"*12, *list(range(12)))
               >>> x = memoryview(buf)
               >>> y = x.cast('i', shape=[2,2,3])
               >>> y.tolist()
               [[[0, 1, 2], [3, 4, 5]], [[6, 7, 8], [9, 10, 11]]]
               >>> y.format
               'i'
               >>> y.itemsize
               4
               >>> len(y)
               2
               >>> y.nbytes
               48
               >>> z = y.cast('b')
               >>> z.format
               'b'
               >>> z.itemsize
               1
               >>> len(z)
               48
               >>> z.nbytes
               48

          Cast 1D/unsigned long to 2D/unsigned long:

               >>> buf = struct.pack("L"*6, *list(range(6)))
               >>> x = memoryview(buf)
               >>> y = x.cast('L', shape=[2,3])
               >>> len(y)
               2
               >>> y.nbytes
               48
               >>> y.tolist()
               [[0, 1, 2], [3, 4, 5]]

          Added in version 3.3.

          Changed in version 3.5: The source format is no longer
          restricted when casting to a byte view.

     There are also several readonly attributes available:

      -- Attribute: obj

          The underlying object of the memoryview:

               >>> b  = bytearray(b'xyz')
               >>> m = memoryview(b)
               >>> m.obj is b
               True

          Added in version 3.3.

      -- Attribute: nbytes

          ‘nbytes == product(shape) * itemsize == len(m.tobytes())’.
          This is the amount of space in bytes that the array would use
          in a contiguous representation.  It is not necessarily equal
          to ‘len(m)’:

               >>> import array
               >>> a = array.array('i', [1,2,3,4,5])
               >>> m = memoryview(a)
               >>> len(m)
               5
               >>> m.nbytes
               20
               >>> y = m[::2]
               >>> len(y)
               3
               >>> y.nbytes
               12
               >>> len(y.tobytes())
               12

          Multi-dimensional arrays:

               >>> import struct
               >>> buf = struct.pack("d"*12, *[1.5*x for x in range(12)])
               >>> x = memoryview(buf)
               >>> y = x.cast('d', shape=[3,4])
               >>> y.tolist()
               [[0.0, 1.5, 3.0, 4.5], [6.0, 7.5, 9.0, 10.5], [12.0, 13.5, 15.0, 16.5]]
               >>> len(y)
               3
               >>> y.nbytes
               96

          Added in version 3.3.

      -- Attribute: readonly

          A bool indicating whether the memory is read only.

      -- Attribute: format

          A string containing the format (in *note struct: d5. module
          style) for each element in the view.  A memoryview can be
          created from exporters with arbitrary format strings, but some
          methods (e.g.  *note tolist(): 23d5.) are restricted to native
          single element formats.

          Changed in version 3.3: format ‘'B'’ is now handled according
          to the struct module syntax.  This means that
          ‘memoryview(b'abc')[0] == b'abc'[0] == 97’.

      -- Attribute: itemsize

          The size in bytes of each element of the memoryview:

               >>> import array, struct
               >>> m = memoryview(array.array('H', [32000, 32001, 32002]))
               >>> m.itemsize
               2
               >>> m[0]
               32000
               >>> struct.calcsize('H') == m.itemsize
               True

      -- Attribute: ndim

          An integer indicating how many dimensions of a
          multi-dimensional array the memory represents.

      -- Attribute: shape

          A tuple of integers the length of *note ndim: 23e0. giving the
          shape of the memory as an N-dimensional array.

          Changed in version 3.3: An empty tuple instead of ‘None’ when
          ndim = 0.

      -- Attribute: strides

          A tuple of integers the length of *note ndim: 23e0. giving the
          size in bytes to access each element for each dimension of the
          array.

          Changed in version 3.3: An empty tuple instead of ‘None’ when
          ndim = 0.

      -- Attribute: suboffsets

          Used internally for PIL-style arrays.  The value is
          informational only.

      -- Attribute: c_contiguous

          A bool indicating whether the memory is C-*note contiguous:
          23dc.

          Added in version 3.3.

      -- Attribute: f_contiguous

          A bool indicating whether the memory is Fortran *note
          contiguous: 23dc.

          Added in version 3.3.

      -- Attribute: contiguous

          A bool indicating whether the memory is *note contiguous:
          23dc.

          Added in version 3.3.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3118/


File: python.info,  Node: Set Types — set frozenset,  Next: Mapping Types — dict,  Prev: Binary Sequence Types — bytes bytearray memoryview,  Up: Built-in Types

5.4.10 Set Types — ‘set’, ‘frozenset’
-------------------------------------

A 'set' object is an unordered collection of distinct *note hashable:
613. objects.  Common uses include membership testing, removing
duplicates from a sequence, and computing mathematical operations such
as intersection, union, difference, and symmetric difference.  (For
other containers see the built-in *note dict: 256, *note list: 614, and
*note tuple: 373. classes, and the *note collections: 1d. module.)

Like other collections, sets support ‘x in set’, ‘len(set)’, and ‘for x
in set’.  Being an unordered collection, sets do not record element
position or order of insertion.  Accordingly, sets do not support
indexing, slicing, or other sequence-like behavior.

There are currently two built-in set types, *note set: 5dc. and *note
frozenset: 5dd.  The ‘set’ type is mutable — the contents can be changed
using methods like *note add(): 20a2. and *note remove(): 23e8.  Since
it is mutable, it has no hash value and cannot be used as either a
dictionary key or as an element of another set.  The ‘frozenset’ type is
immutable and *note hashable: 613. — its contents cannot be altered
after it is created; it can therefore be used as a dictionary key or as
an element of another set.

Non-empty sets (not frozensets) can be created by placing a
comma-separated list of elements within braces, for example: ‘{'jack',
'sjoerd'}’, in addition to the *note set: 5dc. constructor.

The constructors for both classes work the same:

 -- Class: set (iterable=(), /)
 -- Class: frozenset (iterable=(), /)

     Return a new set or frozenset object whose elements are taken from
     'iterable'.  The elements of a set must be *note hashable: 613.  To
     represent sets of sets, the inner sets must be ‘frozenset’ objects.
     If 'iterable' is not specified, a new empty set is returned.

Sets can be created by several means:

   * Use a comma-separated list of elements within braces: ‘{'jack',
     'sjoerd'}’

   * Use a set comprehension: ‘{c for c in 'abracadabra' if c not in
     'abc'}’

   * Use the type constructor: ‘set()’, ‘set('foobar')’, ‘set(['a', 'b',
     'foo'])’

Instances of *note set: 5dc. and *note frozenset: 5dd. provide the
following operations:

 -- Describe: len(s)

     Return the number of elements in set 's' (cardinality of 's').

 -- Describe: x in s

     Test 'x' for membership in 's'.

 -- Describe: x not in s

     Test 'x' for non-membership in 's'.

 -- Method: frozenset.isdisjoint (other, /)
 -- Method: set.isdisjoint (other, /)

     Return ‘True’ if the set has no elements in common with 'other'.
     Sets are disjoint if and only if their intersection is the empty
     set.

 -- Method: frozenset.issubset (other, /)
 -- Method: set.issubset (other, /)

 -- Describe: set <= other

     Test whether every element in the set is in 'other'.

 -- Describe: set < other

     Test whether the set is a proper subset of 'other', that is, ‘set
     <= other and set != other’.

 -- Method: frozenset.issuperset (other, /)
 -- Method: set.issuperset (other, /)

 -- Describe: set >= other

     Test whether every element in 'other' is in the set.

 -- Describe: set > other

     Test whether the set is a proper superset of 'other', that is, ‘set
     >= other and set != other’.

 -- Method: frozenset.union (*others)
 -- Method: set.union (*others)

 -- Describe: set | other | ...

     Return a new set with elements from the set and all others.

 -- Method: frozenset.intersection (*others)
 -- Method: set.intersection (*others)

 -- Describe: set & other & ...

     Return a new set with elements common to the set and all others.

 -- Method: frozenset.difference (*others)
 -- Method: set.difference (*others)

 -- Describe: set - other - ...

     Return a new set with elements in the set that are not in the
     others.

 -- Method: frozenset.symmetric_difference (other, /)
 -- Method: set.symmetric_difference (other, /)

 -- Describe: set ^ other

     Return a new set with elements in either the set or 'other' but not
     both.

 -- Method: frozenset.copy ()
 -- Method: set.copy ()

     Return a shallow copy of the set.

Note, the non-operator versions of *note union(): 14d2, *note
intersection(): 14d3, *note difference(): 23ef, *note
symmetric_difference(): 23f1, *note issubset(): 23eb, and *note
issuperset(): 23ed. methods will accept any iterable as an argument.  In
contrast, their operator based counterparts require their arguments to
be sets.  This precludes error-prone constructions like ‘set('abc') &
'cbs'’ in favor of the more readable ‘set('abc').intersection('cbs')’.

Both *note set: 5dc. and *note frozenset: 5dd. support set to set
comparisons.  Two sets are equal if and only if every element of each
set is contained in the other (each is a subset of the other).  A set is
less than another set if and only if the first set is a proper subset of
the second set (is a subset, but is not equal).  A set is greater than
another set if and only if the first set is a proper superset of the
second set (is a superset, but is not equal).

Instances of *note set: 5dc. are compared to instances of *note
frozenset: 5dd. based on their members.  For example, ‘set('abc') ==
frozenset('abc')’ returns ‘True’ and so does ‘set('abc') in
set([frozenset('abc')])’.

The subset and equality comparisons do not generalize to a total
ordering function.  For example, any two nonempty disjoint sets are not
equal and are not subsets of each other, so 'all' of the following
return ‘False’: ‘a<b’, ‘a==b’, or ‘a>b’.

Since sets only define partial ordering (subset relationships), the
output of the *note list.sort(): bee. method is undefined for lists of
sets.

Set elements, like dictionary keys, must be *note hashable: 613.

Binary operations that mix *note set: 5dc. instances with *note
frozenset: 5dd. return the type of the first operand.  For example:
‘frozenset('ab') | set('bc')’ returns an instance of ‘frozenset’.

The following table lists operations available for *note set: 5dc. that
do not apply to immutable instances of *note frozenset: 5dd.:

 -- Method: set.update (*others)

 -- Describe: set |= other | ...

     Update the set, adding elements from all others.

 -- Method: set.intersection_update (*others)

 -- Describe: set &= other & ...

     Update the set, keeping only elements found in it and all others.

 -- Method: set.difference_update (*others)

 -- Describe: set -= other | ...

     Update the set, removing elements found in others.

 -- Method: set.symmetric_difference_update (other, /)

 -- Describe: set ^= other

     Update the set, keeping only elements found in either set, but not
     in both.

 -- Method: set.add (elem, /)

     Add element 'elem' to the set.

 -- Method: set.remove (elem, /)

     Remove element 'elem' from the set.  Raises *note KeyError: 345. if
     'elem' is not contained in the set.

 -- Method: set.discard (elem, /)

     Remove element 'elem' from the set if it is present.

 -- Method: set.pop ()

     Remove and return an arbitrary element from the set.  Raises *note
     KeyError: 345. if the set is empty.

 -- Method: set.clear ()

     Remove all elements from the set.

Note, the non-operator versions of the *note update(): 23f5, *note
intersection_update(): 14d4, *note difference_update(): 23f6, and *note
symmetric_difference_update(): 14d5. methods will accept any iterable as
an argument.

Note, the 'elem' argument to the *note __contains__(): 1406, *note
remove(): 23e8, and *note discard(): 23f7. methods may be a set.  To
support searching for an equivalent frozenset, a temporary one is
created from 'elem'.


File: python.info,  Node: Mapping Types — dict,  Next: Context Manager Types,  Prev: Set Types — set frozenset,  Up: Built-in Types

5.4.11 Mapping Types — ‘dict’
-----------------------------

A *note mapping: 1200. object maps *note hashable: 613. values to
arbitrary objects.  Mappings are mutable objects.  There is currently
only one standard mapping type, the 'dictionary'.  (For other containers
see the built-in *note list: 614, *note set: 5dc, and *note tuple: 373.
classes, and the *note collections: 1d. module.)

A dictionary’s keys are 'almost' arbitrary values.  Values that are not
*note hashable: 613, that is, values containing lists, dictionaries or
other mutable types (that are compared by value rather than by object
identity) may not be used as keys.  Values that compare equal (such as
‘1’, ‘1.0’, and ‘True’) can be used interchangeably to index the same
dictionary entry.

 -- Class: dict (**kwargs)

 -- Class: dict (mapping, /, **kwargs)

 -- Class: dict (iterable, /, **kwargs)

     Return a new dictionary initialized from an optional positional
     argument and a possibly empty set of keyword arguments.

     Dictionaries can be created by several means:

        * Use a comma-separated list of ‘key: value’ pairs within
          braces: ‘{'jack': 4098, 'sjoerd': 4127}’ or ‘{4098: 'jack',
          4127: 'sjoerd'}’

        * Use a dict comprehension: ‘{}’, ‘{x: x ** 2 for x in
          range(10)}’

        * Use the type constructor: ‘dict()’, ‘dict([('foo', 100),
          ('bar', 200)])’, ‘dict(foo=100, bar=200)’

     If no positional argument is given, an empty dictionary is created.
     If a positional argument is given and it defines a ‘keys()’ method,
     a dictionary is created by calling *note __getitem__(): 283. on the
     argument with each returned key from the method.  Otherwise, the
     positional argument must be an *note iterable: 126d. object.  Each
     item in the iterable must itself be an iterable with exactly two
     elements.  The first element of each item becomes a key in the new
     dictionary, and the second element the corresponding value.  If a
     key occurs more than once, the last value for that key becomes the
     corresponding value in the new dictionary.

     If keyword arguments are given, the keyword arguments and their
     values are added to the dictionary created from the positional
     argument.  If a key being added is already present, the value from
     the keyword argument replaces the value from the positional
     argument.

     Dictionaries compare equal if and only if they have the same ‘(key,
     value)’ pairs (regardless of ordering).  Order comparisons (‘<’,
     ‘<=’, ‘>=’, ‘>’) raise *note TypeError: 2c3.  To illustrate
     dictionary creation and equality, the following examples all return
     a dictionary equal to ‘{"one": 1, "two": 2, "three": 3}’:

          >>> a = dict(one=1, two=2, three=3)
          >>> b = {'one': 1, 'two': 2, 'three': 3}
          >>> c = dict(zip(['one', 'two', 'three'], [1, 2, 3]))
          >>> d = dict([('two', 2), ('one', 1), ('three', 3)])
          >>> e = dict({'three': 3, 'one': 1, 'two': 2})
          >>> f = dict({'one': 1, 'three': 3}, two=2)
          >>> a == b == c == d == e == f
          True

     Providing keyword arguments as in the first example only works for
     keys that are valid Python identifiers.  Otherwise, any valid keys
     can be used.

     Dictionaries preserve insertion order.  Note that updating a key
     does not affect the order.  Keys added after deletion are inserted
     at the end.

          >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
          >>> d
          {'one': 1, 'two': 2, 'three': 3, 'four': 4}
          >>> list(d)
          ['one', 'two', 'three', 'four']
          >>> list(d.values())
          [1, 2, 3, 4]
          >>> d["one"] = 42
          >>> d
          {'one': 42, 'two': 2, 'three': 3, 'four': 4}
          >>> del d["two"]
          >>> d["two"] = None
          >>> d
          {'one': 42, 'three': 3, 'four': 4, 'two': None}

     Changed in version 3.7: Dictionary order is guaranteed to be
     insertion order.  This behavior was an implementation detail of
     CPython from 3.6.

     These are the operations that dictionaries support (and therefore,
     custom mapping types should support too):

      -- Describe: list(d)

          Return a list of all the keys used in the dictionary 'd'.

      -- Describe: len(d)

          Return the number of items in the dictionary 'd'.

      -- Describe: d[key]

          Return the item of 'd' with key 'key'.  Raises a *note
          KeyError: 345. if 'key' is not in the map.

          If a subclass of dict defines a method *note __missing__():
          1202. and 'key' is not present, the ‘d[key]’ operation calls
          that method with the key 'key' as argument.  The ‘d[key]’
          operation then returns or raises whatever is returned or
          raised by the ‘__missing__(key)’ call.  No other operations or
          methods invoke ‘__missing__()’.  If ‘__missing__()’ is not
          defined, *note KeyError: 345. is raised.  ‘__missing__()’ must
          be a method; it cannot be an instance variable:

               >>> class Counter(dict):
               ...     def __missing__(self, key):
               ...         return 0
               ...
               >>> c = Counter()
               >>> c['red']
               0
               >>> c['red'] += 1
               >>> c['red']
               1

          The example above shows part of the implementation of *note
          collections.Counter: 10d5.  A different ‘__missing__()’ method
          is used by *note collections.defaultdict: 1201.

      -- Describe: d[key] = value

          Set ‘d[key]’ to 'value'.

      -- Describe: del d[key]

          Remove ‘d[key]’ from 'd'.  Raises a *note KeyError: 345. if
          'key' is not in the map.

      -- Describe: key in d

          Return ‘True’ if 'd' has a key 'key', else ‘False’.

      -- Describe: key not in d

          Equivalent to ‘not key in d’.

      -- Describe: iter(d)

          Return an iterator over the keys of the dictionary.  This is a
          shortcut for ‘iter(d.keys())’.

      -- Method: clear ()

          Remove all items from the dictionary.

      -- Method: copy ()

          Return a shallow copy of the dictionary.

      -- Method: classmethod fromkeys (iterable, value=None, /)

          Create a new dictionary with keys from 'iterable' and values
          set to 'value'.

          ‘fromkeys()’ is a class method that returns a new dictionary.
          'value' defaults to ‘None’.  All of the values refer to just a
          single instance, so it generally doesn’t make sense for
          'value' to be a mutable object such as an empty list.  To get
          distinct values, use a *note dict comprehension: dad. instead.

      -- Method: get (key, default=None, /)

          Return the value for 'key' if 'key' is in the dictionary, else
          'default'.  If 'default' is not given, it defaults to ‘None’,
          so that this method never raises a *note KeyError: 345.

      -- Method: items ()

          Return a new view of the dictionary’s items (‘(key, value)’
          pairs).  See the *note documentation of view objects: 23fb.

      -- Method: keys ()

          Return a new view of the dictionary’s keys.  See the *note
          documentation of view objects: 23fb.

      -- Method: pop (key, /)

      -- Method: pop (key, default, /)

          If 'key' is in the dictionary, remove it and return its value,
          else return 'default'.  If 'default' is not given and 'key' is
          not in the dictionary, a *note KeyError: 345. is raised.

      -- Method: popitem ()

          Remove and return a ‘(key, value)’ pair from the dictionary.
          Pairs are returned in LIFO (last-in, first-out) order.

          ‘popitem()’ is useful to destructively iterate over a
          dictionary, as often used in set algorithms.  If the
          dictionary is empty, calling ‘popitem()’ raises a *note
          KeyError: 345.

          Changed in version 3.7: LIFO order is now guaranteed.  In
          prior versions, ‘popitem()’ would return an arbitrary
          key/value pair.

      -- Describe: reversed(d)

          Return a reverse iterator over the keys of the dictionary.
          This is a shortcut for ‘reversed(d.keys())’.

          Added in version 3.8.

      -- Method: setdefault (key, default=None, /)

          If 'key' is in the dictionary, return its value.  If not,
          insert 'key' with a value of 'default' and return 'default'.
          'default' defaults to ‘None’.

      -- Method: update (**kwargs)

      -- Method: update (mapping, /, **kwargs)

      -- Method: update (iterable, /, **kwargs)

          Update the dictionary with the key/value pairs from 'mapping'
          or 'iterable' and 'kwargs', overwriting existing keys.  Return
          ‘None’.

          ‘update()’ accepts either another object with a ‘keys()’
          method (in which case *note __getitem__(): 283. is called with
          every key returned from the method) or an iterable of
          key/value pairs (as tuples or other iterables of length two).
          If keyword arguments are specified, the dictionary is then
          updated with those key/value pairs: ‘d.update(red=1, blue=2)’.

      -- Method: values ()

          Return a new view of the dictionary’s values.  See the *note
          documentation of view objects: 23fb.

          An equality comparison between one ‘dict.values()’ view and
          another will always return ‘False’.  This also applies when
          comparing ‘dict.values()’ to itself:

               >>> d = {'a': 1}
               >>> d.values() == d.values()
               False

      -- Describe: d | other

          Create a new dictionary with the merged keys and values of 'd'
          and 'other', which must both be dictionaries.  The values of
          'other' take priority when 'd' and 'other' share keys.

          Added in version 3.9.

      -- Describe: d |= other

          Update the dictionary 'd' with keys and values from 'other',
          which may be either a *note mapping: 1200. or an *note
          iterable: 126d. of key/value pairs.  The values of 'other'
          take priority when 'd' and 'other' share keys.

          Added in version 3.9.

     Dictionaries and dictionary views are reversible.

          >>> d = {"one": 1, "two": 2, "three": 3, "four": 4}
          >>> d
          {'one': 1, 'two': 2, 'three': 3, 'four': 4}
          >>> list(reversed(d))
          ['four', 'three', 'two', 'one']
          >>> list(reversed(d.values()))
          [4, 3, 2, 1]
          >>> list(reversed(d.items()))
          [('four', 4), ('three', 3), ('two', 2), ('one', 1)]

     Changed in version 3.8: Dictionaries are now reversible.

See also
........

*note types.MappingProxyType: 470. can be used to create a read-only
view of a *note dict: 256.

* Menu:

* Dictionary view objects::


File: python.info,  Node: Dictionary view objects,  Up: Mapping Types — dict

5.4.11.1 Dictionary view objects
................................

The objects returned by *note dict.keys(): 7d1, *note dict.values():
7d2. and *note dict.items(): 7d3. are 'view objects'.  They provide a
dynamic view on the dictionary’s entries, which means that when the
dictionary changes, the view reflects these changes.

Dictionary views can be iterated over to yield their respective data,
and support membership tests:

 -- Describe: len(dictview)

     Return the number of entries in the dictionary.

 -- Describe: iter(dictview)

     Return an iterator over the keys, values or items (represented as
     tuples of ‘(key, value)’) in the dictionary.

     Keys and values are iterated over in insertion order.  This allows
     the creation of ‘(value, key)’ pairs using *note zip(): 7d4.:
     ‘pairs = zip(d.values(), d.keys())’.  Another way to create the
     same list is ‘pairs = [(v, k) for (k, v) in d.items()]’.

     Iterating views while adding or deleting entries in the dictionary
     may raise a *note RuntimeError: 195. or fail to iterate over all
     entries.

     Changed in version 3.7: Dictionary order is guaranteed to be
     insertion order.

 -- Describe: x in dictview

     Return ‘True’ if 'x' is in the underlying dictionary’s keys, values
     or items (in the latter case, 'x' should be a ‘(key, value)’
     tuple).

 -- Describe: reversed(dictview)

     Return a reverse iterator over the keys, values or items of the
     dictionary.  The view will be iterated in reverse order of the
     insertion.

     Changed in version 3.8: Dictionary views are now reversible.

 -- Describe: dictview.mapping

     Return a *note types.MappingProxyType: 470. that wraps the original
     dictionary to which the view refers.

     Added in version 3.10.

Keys views are set-like since their entries are unique and *note
hashable: 613.  Items views also have set-like operations since the
(key, value) pairs are unique and the keys are hashable.  If all values
in an items view are hashable as well, then the items view can
interoperate with other sets.  (Values views are not treated as set-like
since the entries are generally not unique.)  For set-like views, all of
the operations defined for the abstract base class *note
collections.abc.Set: 23fd. are available (for example, ‘==’, ‘<’, or
‘^’).  While using set operators, set-like views accept any iterable as
the other operand, unlike sets which only accept sets as the input.

An example of dictionary view usage:

     >>> dishes = {'eggs': 2, 'sausage': 1, 'bacon': 1, 'spam': 500}
     >>> keys = dishes.keys()
     >>> values = dishes.values()

     >>> # iteration
     >>> n = 0
     >>> for val in values:
     ...     n += val
     ...
     >>> print(n)
     504

     >>> # keys and values are iterated over in the same order (insertion order)
     >>> list(keys)
     ['eggs', 'sausage', 'bacon', 'spam']
     >>> list(values)
     [2, 1, 1, 500]

     >>> # view objects are dynamic and reflect dict changes
     >>> del dishes['eggs']
     >>> del dishes['sausage']
     >>> list(keys)
     ['bacon', 'spam']

     >>> # set operations
     >>> keys & {'eggs', 'bacon', 'salad'}
     {'bacon'}
     >>> keys ^ {'sausage', 'juice'} == {'juice', 'sausage', 'bacon', 'spam'}
     True
     >>> keys | ['juice', 'juice', 'juice'] == {'bacon', 'spam', 'juice'}
     True

     >>> # get back a read-only proxy for the original dictionary
     >>> values.mapping
     mappingproxy({'bacon': 1, 'spam': 500})
     >>> values.mapping['spam']
     500


File: python.info,  Node: Context Manager Types,  Next: Type Annotation Types — Generic Alias Union,  Prev: Mapping Types — dict,  Up: Built-in Types

5.4.12 Context Manager Types
----------------------------

Python’s *note with: 5d5. statement supports the concept of a runtime
context defined by a context manager.  This is implemented using a pair
of methods that allow user-defined classes to define a runtime context
that is entered before the statement body is executed and exited when
the statement ends:

 -- Method: contextmanager.__enter__ ()

     Enter the runtime context and return either this object or another
     object related to the runtime context.  The value returned by this
     method is bound to the identifier in the ‘as’ clause of *note with:
     5d5. statements using this context manager.

     An example of a context manager that returns itself is a *note file
     object: 1208.  File objects return themselves from __enter__() to
     allow *note open(): 51f. to be used as the context expression in a
     *note with: 5d5. statement.

     An example of a context manager that returns a related object is
     the one returned by *note decimal.localcontext(): 13d3.  These
     managers set the active decimal context to a copy of the original
     decimal context and then return the copy.  This allows changes to
     be made to the current decimal context in the body of the *note
     with: 5d5. statement without affecting code outside the ‘with’
     statement.

 -- Method: contextmanager.__exit__ (exc_type, exc_val, exc_tb)

     Exit the runtime context and return a Boolean flag indicating if
     any exception that occurred should be suppressed.  If an exception
     occurred while executing the body of the *note with: 5d5.
     statement, the arguments contain the exception type, value and
     traceback information.  Otherwise, all three arguments are ‘None’.

     Returning a true value from this method will cause the *note with:
     5d5. statement to suppress the exception and continue execution
     with the statement immediately following the ‘with’ statement.
     Otherwise the exception continues propagating after this method has
     finished executing.

     If this method raises an exception while handling an earlier
     exception from the *note with: 5d5. block, the new exception is
     raised, and the original exception is stored in its *note
     __context__: 130f. attribute.

     The exception passed in should never be reraised explicitly -
     instead, this method should return a false value to indicate that
     the method completed successfully and does not want to suppress the
     raised exception.  This allows context management code to easily
     detect whether or not an *note __exit__(): 1349. method has
     actually failed.

Python defines several context managers to support easy thread
synchronisation, prompt closure of files or other objects, and simpler
manipulation of the active decimal arithmetic context.  The specific
types are not treated specially beyond their implementation of the
context management protocol.  See the *note contextlib: 23. module for
some examples.

Python’s *note generator: 109f.s and the *note
contextlib.contextmanager: 1247. decorator provide a convenient way to
implement these protocols.  If a generator function is decorated with
the ‘contextlib.contextmanager’ decorator, it will return a context
manager implementing the necessary *note __enter__(): 23ff. and *note
__exit__(): 2400. methods, rather than the iterator produced by an
undecorated generator function.

Note that there is no specific slot for any of these methods in the type
structure for Python objects in the Python/C API. Extension types
wanting to define these methods must provide them as a normal Python
accessible method.  Compared to the overhead of setting up the runtime
context, the overhead of a single class dictionary lookup is negligible.


File: python.info,  Node: Type Annotation Types — Generic Alias Union,  Next: Other Built-in Types,  Prev: Context Manager Types,  Up: Built-in Types

5.4.13 Type Annotation Types — Generic Alias, Union
---------------------------------------------------

The core built-in types for *note type annotations: 45b. are *note
Generic Alias: 6b5. and *note Union: 7c6.

* Menu:

* Generic Alias Type::
* Union Type::


File: python.info,  Node: Generic Alias Type,  Next: Union Type,  Up: Type Annotation Types — Generic Alias Union

5.4.13.1 Generic Alias Type
...........................

‘GenericAlias’ objects are generally created by *note subscripting:
2134. a class.  They are most often used with *note container classes:
213a, such as *note list: 614. or *note dict: 256.  For example,
‘list[int]’ is a ‘GenericAlias’ object created by subscripting the
‘list’ class with the argument *note int: 257.  ‘GenericAlias’ objects
are intended primarily for use with *note type annotations: 45b.

     Note: It is generally only possible to subscript a class if the
     class implements the special method *note __class_getitem__(): 73e.

A ‘GenericAlias’ object acts as a proxy for a *note generic type: 43c,
implementing 'parameterized generics'.

For a container class, the argument(s) supplied to a *note subscription:
2134. of the class may indicate the type(s) of the elements an object
contains.  For example, ‘set[bytes]’ can be used in type annotations to
signify a *note set: 5dc. in which all the elements are of type *note
bytes: 1c2.

For a class which defines *note __class_getitem__(): 73e. but is not a
container, the argument(s) supplied to a subscription of the class will
often indicate the return type(s) of one or more methods defined on an
object.  For example, *note regular expressions: b9. can be used on both
the *note str: 44f. data type and the *note bytes: 1c2. data type:

   * If ‘x = re.search('foo', 'foo')’, ‘x’ will be a *note re.Match:
     fc1. object where the return values of ‘x.group(0)’ and ‘x[0]’ will
     both be of type *note str: 44f.  We can represent this kind of
     object in type annotations with the ‘GenericAlias’ ‘re.Match[str]’.

   * If ‘y = re.search(b'bar', b'bar')’, (note the ‘b’ for *note bytes:
     1c2.), ‘y’ will also be an instance of ‘re.Match’, but the return
     values of ‘y.group(0)’ and ‘y[0]’ will both be of type ‘bytes’.  In
     type annotations, we would represent this variety of *note
     re.Match: fc1. objects with ‘re.Match[bytes]’.

‘GenericAlias’ objects are instances of the class *note
types.GenericAlias: 7f0, which can also be used to create ‘GenericAlias’
objects directly.

 -- Describe: T[X, Y, ...]

     Creates a ‘GenericAlias’ representing a type ‘T’ parameterized by
     types 'X', 'Y', and more depending on the ‘T’ used.  For example, a
     function expecting a *note list: 614. containing *note float: 2f7.
     elements:

          def average(values: list[float]) -> float:
              return sum(values) / len(values)

     Another example for *note mapping: 1200. objects, using a *note
     dict: 256, which is a generic type expecting two type parameters
     representing the key type and the value type.  In this example, the
     function expects a ‘dict’ with keys of type *note str: 44f. and
     values of type *note int: 257.:

          def send_post_request(url: str, body: dict[str, int]) -> None:
              ...

The builtin functions *note isinstance(): 445. and *note issubclass():
7c5. do not accept ‘GenericAlias’ types for their second argument:

     >>> isinstance([1, 2], list[str])
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: isinstance() argument 2 cannot be a parameterized generic

The Python runtime does not enforce *note type annotations: 45b.  This
extends to generic types and their type parameters.  When creating a
container object from a ‘GenericAlias’, the elements in the container
are not checked against their type.  For example, the following code is
discouraged, but will run without errors:

     >>> t = list[str]
     >>> t([1, 2, 3])
     [1, 2, 3]

Furthermore, parameterized generics erase type parameters during object
creation:

     >>> t = list[str]
     >>> type(t)
     <class 'types.GenericAlias'>

     >>> l = t()
     >>> type(l)
     <class 'list'>

Calling *note repr(): 803. or *note str(): 44f. on a generic shows the
parameterized type:

     >>> repr(list[int])
     'list[int]'

     >>> str(list[int])
     'list[int]'

The *note __getitem__(): 283. method of generic containers will raise an
exception to disallow mistakes like ‘dict[str][str]’:

     >>> dict[str][str]
     Traceback (most recent call last):
       ...
     TypeError: dict[str] is not a generic class

However, such expressions are valid when *note type variables: 212f. are
used.  The index must have as many elements as there are type variable
items in the ‘GenericAlias’ object’s *note __args__: 2403.

     >>> from typing import TypeVar
     >>> Y = TypeVar('Y')
     >>> dict[str, Y][int]
     dict[str, int]

* Menu:

* Standard Generic Classes::
* Special Attributes of GenericAlias objects::


File: python.info,  Node: Standard Generic Classes,  Next: Special Attributes of GenericAlias objects,  Up: Generic Alias Type

5.4.13.2 Standard Generic Classes
.................................

The following standard library classes support parameterized generics.
This list is non-exhaustive.

   * *note tuple: 373.

   * *note list: 614.

   * *note dict: 256.

   * *note set: 5dc.

   * *note frozenset: 5dd.

   * *note type: d71.

   * *note asyncio.Future: bec.

   * *note asyncio.Task: 1be.

   * *note collections.deque: 5df.

   * *note collections.defaultdict: 1201.

   * *note collections.OrderedDict: 5de.

   * *note collections.Counter: 10d5.

   * *note collections.ChainMap: c3c.

   * *note collections.abc.Awaitable: e0c.

   * *note collections.abc.Coroutine: e0d.

   * *note collections.abc.AsyncIterable: e0f.

   * *note collections.abc.AsyncIterator: e0e.

   * *note collections.abc.AsyncGenerator: cae.

   * *note collections.abc.Iterable: 2405.

   * *note collections.abc.Iterator: 2406.

   * *note collections.abc.Generator: e0b.

   * *note collections.abc.Reversible: cac.

   * *note collections.abc.Container: 2407.

   * *note collections.abc.Collection: cab.

   * *note collections.abc.Callable: 7ef.

   * *note collections.abc.Set: 23fd.

   * *note collections.abc.MutableSet: 2408.

   * *note collections.abc.Mapping: 8d3.

   * *note collections.abc.MutableMapping: 10f0.

   * *note collections.abc.Sequence: 1209.

   * *note collections.abc.MutableSequence: 1a1.

   * *note collections.abc.ByteString: 2e7.

   * *note collections.abc.MappingView: 2409.

   * *note collections.abc.KeysView: 240a.

   * *note collections.abc.ItemsView: 240b.

   * *note collections.abc.ValuesView: 240c.

   * *note contextlib.AbstractContextManager: cb1.

   * *note contextlib.AbstractAsyncContextManager: b43.

   * *note dataclasses.Field: 240d.

   * *note functools.cached_property: 544.

   * *note functools.partialmethod: a8a.

   * *note os.PathLike: c72.

   * *note queue.LifoQueue: 240e.

   * *note queue.Queue: 13e1.

   * *note queue.PriorityQueue: 240f.

   * *note queue.SimpleQueue: b86.

   * *note re.Pattern: fc0.

   * *note re.Match: fc1.

   * *note shelve.BsdDbShelf: 2410.

   * *note shelve.DbfilenameShelf: 2411.

   * *note shelve.Shelf: fd4.

   * *note types.MappingProxyType: 470.

   * *note weakref.WeakKeyDictionary: 1b00.

   * *note weakref.WeakMethod: 102a.

   * *note weakref.WeakSet: 5e0.

   * *note weakref.WeakValueDictionary: 1aff.


File: python.info,  Node: Special Attributes of GenericAlias objects,  Prev: Standard Generic Classes,  Up: Generic Alias Type

5.4.13.3 Special Attributes of ‘GenericAlias’ objects
.....................................................

All parameterized generics implement special read-only attributes.

 -- Attribute: genericalias.__origin__

     This attribute points at the non-parameterized generic class:

          >>> list[int].__origin__
          <class 'list'>

 -- Attribute: genericalias.__args__

     This attribute is a *note tuple: 373. (possibly of length 1) of
     generic types passed to the original *note __class_getitem__():
     73e. of the generic class:

          >>> dict[str, list[int]].__args__
          (<class 'str'>, list[int])

 -- Attribute: genericalias.__parameters__

     This attribute is a lazily computed tuple (possibly empty) of
     unique type variables found in ‘__args__’:

          >>> from typing import TypeVar

          >>> T = TypeVar('T')
          >>> list[T].__parameters__
          (~T,)

          Note: A ‘GenericAlias’ object with *note typing.ParamSpec:
          15e. parameters may not have correct ‘__parameters__’ after
          substitution because ‘typing.ParamSpec’ is intended primarily
          for static type checking.

 -- Attribute: genericalias.__unpacked__

     A boolean that is true if the alias has been unpacked using the ‘*’
     operator (see *note TypeVarTuple: 15f.).

     Added in version 3.11.

See also
........

PEP 484(1) - Type Hints

     Introducing Python’s framework for type annotations.

PEP 585(2) - Type Hinting Generics In Standard Collections

     Introducing the ability to natively parameterize standard-library
     classes, provided they implement the special class method *note
     __class_getitem__(): 73e.

*note Generics: 212f, *note user-defined generics: 4d2. and *note typing.Generic: 15fb.

     Documentation on how to implement generic classes that can be
     parameterized at runtime and understood by static type-checkers.

Added in version 3.9.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0585/


File: python.info,  Node: Union Type,  Prev: Generic Alias Type,  Up: Type Annotation Types — Generic Alias Union

5.4.13.4 Union Type
...................

A union object holds the value of the ‘|’ (bitwise or) operation on
multiple *note type objects: 233a.  These types are intended primarily
for *note type annotations: 45b.  The union type expression enables
cleaner type hinting syntax compared to *note typing.Union: 63e.

 -- Describe: X | Y | ...

     Defines a union object which holds types 'X', 'Y', and so forth.
     ‘X | Y’ means either X or Y. It is equivalent to ‘typing.Union[X,
     Y]’.  For example, the following function expects an argument of
     type *note int: 257. or *note float: 2f7.:

          def square(number: int | float) -> int | float:
              return number ** 2

          Note: The ‘|’ operand cannot be used at runtime to define
          unions where one or more members is a forward reference.  For
          example, ‘int | "Foo"’, where ‘"Foo"’ is a reference to a
          class not yet defined, will fail at runtime.  For unions which
          include forward references, present the whole expression as a
          string, e.g.  ‘"int | Foo"’.

 -- Describe: union_object == other

     Union objects can be tested for equality with other union objects.
     Details:

        * Unions of unions are flattened:

               (int | str) | float == int | str | float

        * Redundant types are removed:

               int | str | int == int | str

        * When comparing unions, the order is ignored:

               int | str == str | int

        * It is compatible with *note typing.Union: 63e.:

               int | str == typing.Union[int, str]

        * Optional types can be spelled as a union with ‘None’:

               str | None == typing.Optional[str]

 -- Describe: isinstance(obj, union_object)

 -- Describe: issubclass(obj, union_object)

     Calls to *note isinstance(): 445. and *note issubclass(): 7c5. are
     also supported with a union object:

          >>> isinstance("", int | str)
          True

     However, *note parameterized generics: 6b5. in union objects cannot
     be checked:

          >>> isinstance(1, int | list[int])  # short-circuit evaluation
          True
          >>> isinstance([1], int | list[int])
          Traceback (most recent call last):
            ...
          TypeError: isinstance() argument 2 cannot be a parameterized generic

The user-exposed type for the union object can be accessed from *note
types.UnionType: 63d. and used for *note isinstance(): 445. checks.  An
object cannot be instantiated from the type:

     >>> import types
     >>> isinstance(int | str, types.UnionType)
     True
     >>> types.UnionType()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: cannot create 'types.UnionType' instances

     Note: The ‘__or__()’ method for type objects was added to support
     the syntax ‘X | Y’.  If a metaclass implements ‘__or__()’, the
     Union may override it:

          >>> class M(type):
          ...     def __or__(self, other):
          ...         return "Hello"
          ...
          >>> class C(metaclass=M):
          ...     pass
          ...
          >>> C | int
          'Hello'
          >>> int | C
          int | C

See also
........

PEP 604(1) – PEP proposing the ‘X | Y’ syntax and the Union type.

Added in version 3.10.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0604/


File: python.info,  Node: Other Built-in Types,  Next: Special Attributes,  Prev: Type Annotation Types — Generic Alias Union,  Up: Built-in Types

5.4.14 Other Built-in Types
---------------------------

The interpreter supports several other kinds of objects.  Most of these
support only one or two operations.

* Menu:

* Modules: Modules<4>.
* Classes and Class Instances::
* Functions::
* Methods::
* Code Objects::
* Type Objects::
* The Null Object::
* The Ellipsis Object::
* The NotImplemented Object::
* Internal Objects::


File: python.info,  Node: Modules<4>,  Next: Classes and Class Instances,  Up: Other Built-in Types

5.4.14.1 Modules
................

The only special operation on a module is attribute access: ‘m.name’,
where 'm' is a module and 'name' accesses a name defined in 'm'’s symbol
table.  Module attributes can be assigned to.  (Note that the *note
import: 5e5. statement is not, strictly speaking, an operation on a
module object; ‘import foo’ does not require a module object named 'foo'
to exist, rather it requires an (external) 'definition' for a module
named 'foo' somewhere.)

A special attribute of every module is *note __dict__: 55e.  This is the
dictionary containing the module’s symbol table.  Modifying this
dictionary will actually change the module’s symbol table, but direct
assignment to the ‘__dict__’ attribute is not possible (you can write
‘m.__dict__['a'] = 1’, which defines ‘m.a’ to be ‘1’, but you can’t
write ‘m.__dict__ = {}’).  Modifying ‘__dict__’ directly is not
recommended.

Modules built into the interpreter are written like this: ‘<module 'sys'
(built-in)>’.  If loaded from a file, they are written as ‘<module 'os'
from '/usr/local/lib/pythonX.Y/os.pyc'>’.


File: python.info,  Node: Classes and Class Instances,  Next: Functions,  Prev: Modules<4>,  Up: Other Built-in Types

5.4.14.2 Classes and Class Instances
....................................

See *note Objects, values and types: 2091. and *note Class definitions:
131f. for these.


File: python.info,  Node: Functions,  Next: Methods,  Prev: Classes and Class Instances,  Up: Other Built-in Types

5.4.14.3 Functions
..................

Function objects are created by function definitions.  The only
operation on a function object is to call it: ‘func(argument-list)’.

There are really two flavors of function objects: built-in functions and
user-defined functions.  Both support the same operation (to call the
function), but the implementation is different, hence the different
object types.

See *note Function definitions: 1dce. for more information.


File: python.info,  Node: Methods,  Next: Code Objects,  Prev: Functions,  Up: Other Built-in Types

5.4.14.4 Methods
................

Methods are functions that are called using the attribute notation.
There are two flavors: *note built-in methods: 20bc. (such as *note
append(): 6d0. on lists) and *note class instance method: 1e5f.
Built-in methods are described with the types that support them.

If you access a method (a function defined in a class namespace) through
an instance, you get a special object: a 'bound method' (also called
*note instance method: 1e5f.) object.  When called, it will add the
‘self’ argument to the argument list.  Bound methods have two special
read-only attributes: *note m.__self__: 1415. is the object on which the
method operates, and *note m.__func__: 1345. is the function
implementing the method.  Calling ‘m(arg-1, arg-2, ..., arg-n)’ is
completely equivalent to calling ‘m.__func__(m.__self__, arg-1, arg-2,
..., arg-n)’.

Like *note function objects: 299, bound method objects support getting
arbitrary attributes.  However, since method attributes are actually
stored on the underlying function object (*note method.__func__: 1345.),
setting method attributes on bound methods is disallowed.  Attempting to
set an attribute on a method results in an *note AttributeError: 34e.
being raised.  In order to set a method attribute, you need to
explicitly set it on the underlying function object:

     >>> class C:
     ...     def method(self):
     ...         pass
     ...
     >>> c = C()
     >>> c.method.whoami = 'my name is method'  # can't set on the method
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     AttributeError: 'method' object has no attribute 'whoami'
     >>> c.method.__func__.whoami = 'my name is method'
     >>> c.method.whoami
     'my name is method'

See *note Instance methods: 1e5f. for more information.


File: python.info,  Node: Code Objects,  Next: Type Objects,  Prev: Methods,  Up: Other Built-in Types

5.4.14.5 Code Objects
.....................

Code objects are used by the implementation to represent
“pseudo-compiled” executable Python code such as a function body.  They
differ from function objects because they don’t contain a reference to
their global execution environment.  Code objects are returned by the
built-in *note compile(): 192. function and can be extracted from
function objects through their *note __code__: 29a. attribute.  See also
the *note code: 1a. module.

Accessing *note __code__: 29a. raises an *note auditing event: 1a15.
‘object.__getattr__’ with arguments ‘obj’ and ‘"__code__"’.

A code object can be executed or evaluated by passing it (instead of a
source string) to the *note exec(): 17f. or *note eval(): 180. built-in
functions.

See *note The standard type hierarchy: 2094. for more information.


File: python.info,  Node: Type Objects,  Next: The Null Object,  Prev: Code Objects,  Up: Other Built-in Types

5.4.14.6 Type Objects
.....................

Type objects represent the various object types.  An object’s type is
accessed by the built-in function *note type(): d71.  There are no
special operations on types.  The standard module *note types: 103.
defines names for all standard built-in types.

Types are written like this: ‘<class 'int'>’.


File: python.info,  Node: The Null Object,  Next: The Ellipsis Object,  Prev: Type Objects,  Up: Other Built-in Types

5.4.14.7 The Null Object
........................

This object is returned by functions that don’t explicitly return a
value.  It supports no special operations.  There is exactly one null
object, named ‘None’ (a built-in name).  ‘type(None)()’ produces the
same singleton.

It is written as ‘None’.


File: python.info,  Node: The Ellipsis Object,  Next: The NotImplemented Object,  Prev: The Null Object,  Up: Other Built-in Types

5.4.14.8 The Ellipsis Object
............................

This object is commonly used to indicate that something is omitted.  It
supports no special operations.  There is exactly one ellipsis object,
named *note Ellipsis: 233f. (a built-in name).  ‘type(Ellipsis)()’
produces the ‘Ellipsis’ singleton.

It is written as ‘Ellipsis’ or ‘...’.

In typical use, ‘...’ as the ‘Ellipsis’ object appears in a few
different places, for instance:

   - In type annotations, such as *note callable arguments: 2427. or
     *note tuple elements: 2428.

   - As the body of a function instead of a *note pass statement: 1db0.

   - In third-party libraries, such as Numpy's slicing and striding(1).

Python also uses three dots in ways that are not ‘Ellipsis’ objects, for
instance:

   - Doctest’s *note ELLIPSIS: 14bd, as a pattern for missing content.

   - The default Python prompt of the *note interactive: 169. shell when
     partial input is incomplete.

Lastly, the Python documentation often uses three dots in conventional
English usage to mean omitted content, even in code examples that also
use them as the ‘Ellipsis’.

   ---------- Footnotes ----------

   (1) 
https://numpy.org/doc/stable/user/basics.indexing.html#slicing-and-striding


File: python.info,  Node: The NotImplemented Object,  Next: Internal Objects,  Prev: The Ellipsis Object,  Up: Other Built-in Types

5.4.14.9 The NotImplemented Object
..................................

This object is returned from comparisons and binary operations when they
are asked to operate on types they don’t support.  See *note
Comparisons: 2228. for more information.  There is exactly one *note
NotImplemented: 7d6. object.  ‘type(NotImplemented)()’ produces the
singleton instance.

It is written as ‘NotImplemented’.


File: python.info,  Node: Internal Objects,  Prev: The NotImplemented Object,  Up: Other Built-in Types

5.4.14.10 Internal Objects
..........................

See *note The standard type hierarchy: 2094. for this information.  It
describes *note stack frame objects: 6e3, *note traceback objects: b0d,
and slice objects.


File: python.info,  Node: Special Attributes,  Next: Integer string conversion length limitation,  Prev: Other Built-in Types,  Up: Built-in Types

5.4.15 Special Attributes
-------------------------

The implementation adds a few special read-only attributes to several
object types, where they are relevant.  Some of these are not reported
by the *note dir(): 635. built-in function.

 -- Attribute: definition.__name__

     The name of the class, function, method, descriptor, or generator
     instance.

 -- Attribute: definition.__qualname__

     The *note qualified name: 1acb. of the class, function, method,
     descriptor, or generator instance.

     Added in version 3.3.

 -- Attribute: definition.__module__

     The name of the module in which a class or function was defined.

 -- Attribute: definition.__doc__

     The documentation string of a class or function, or ‘None’ if
     undefined.

 -- Attribute: definition.__type_params__

     The *note type parameters: 2b3. of generic classes, functions, and
     *note type aliases: 457.  For classes and functions that are not
     generic, this will be an empty tuple.

     Added in version 3.12.


File: python.info,  Node: Integer string conversion length limitation,  Prev: Special Attributes,  Up: Built-in Types

5.4.16 Integer string conversion length limitation
--------------------------------------------------

CPython has a global limit for converting between *note int: 257. and
*note str: 44f. to mitigate denial of service attacks.  This limit
'only' applies to decimal or other non-power-of-two number bases.
Hexadecimal, octal, and binary conversions are unlimited.  The limit can
be configured.

The *note int: 257. type in CPython is an arbitrary length number stored
in binary form (commonly known as a “bignum”).  There exists no
algorithm that can convert a string to a binary integer or a binary
integer to a string in linear time, 'unless' the base is a power of 2.
Even the best known algorithms for base 10 have sub-quadratic
complexity.  Converting a large value such as ‘int('1' * 500_000)’ can
take over a second on a fast CPU.

Limiting conversion size offers a practical way to avoid CVE
2020-10735(1).

The limit is applied to the number of digit characters in the input or
output string when a non-linear conversion algorithm would be involved.
Underscores and the sign are not counted towards the limit.

When an operation would exceed the limit, a *note ValueError: 202. is
raised:

     >>> import sys
     >>> sys.set_int_max_str_digits(4300)  # Illustrative, this is the default.
     >>> _ = int('2' * 5432)
     Traceback (most recent call last):
     ...
     ValueError: Exceeds the limit (4300 digits) for integer string conversion: value has 5432 digits; use sys.set_int_max_str_digits() to increase the limit
     >>> i = int('2' * 4300)
     >>> len(str(i))
     4300
     >>> i_squared = i*i
     >>> len(str(i_squared))
     Traceback (most recent call last):
     ...
     ValueError: Exceeds the limit (4300 digits) for integer string conversion; use sys.set_int_max_str_digits() to increase the limit
     >>> len(hex(i_squared))
     7144
     >>> assert int(hex(i_squared), base=16) == i*i  # Hexadecimal is unlimited.

The default limit is 4300 digits as provided in *note
sys.int_info.default_max_str_digits: 12da.  The lowest limit that can be
configured is 640 digits as provided in
‘sys.int_info.str_digits_check_threshold’.

Verification:

     >>> import sys
     >>> assert sys.int_info.default_max_str_digits == 4300, sys.int_info
     >>> assert sys.int_info.str_digits_check_threshold == 640, sys.int_info
     >>> msg = int('578966293710682886880994035146873798396722250538762761564'
     ...           '9252925514383915483333812743580549779436104706260696366600'
     ...           '571186405732').to_bytes(53, 'big')
     ...

Added in version 3.11.

* Menu:

* Affected APIs::
* Configuring the limit::
* Recommended configuration::

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2020-10735


File: python.info,  Node: Affected APIs,  Next: Configuring the limit,  Up: Integer string conversion length limitation

5.4.16.1 Affected APIs
......................

The limitation only applies to potentially slow conversions between
*note int: 257. and *note str: 44f. or *note bytes: 1c2.:

   * ‘int(string)’ with default base 10.

   * ‘int(string, base)’ for all bases that are not a power of 2.

   * ‘str(integer)’.

   * ‘repr(integer)’.

   * any other string conversion to base 10, for example ‘f"{integer}"’,
     ‘"{}".format(integer)’, or ‘b"%d" % integer’.

The limitations do not apply to functions with a linear algorithm:

   * ‘int(string, base)’ with base 2, 4, 8, 16, or 32.

   * *note int.from_bytes(): 198d. and *note int.to_bytes(): 19d8.

   * *note hex(): 1317, *note oct(): 1316, *note bin(): 12f0.

   * *note Format specification mini-language: 1e8. for hex, octal, and
     binary numbers.

   * *note str: 44f. to *note float: 2f7.

   * *note str: 44f. to *note decimal.Decimal: 29d.


File: python.info,  Node: Configuring the limit,  Next: Recommended configuration,  Prev: Affected APIs,  Up: Integer string conversion length limitation

5.4.16.2 Configuring the limit
..............................

Before Python starts up you can use an environment variable or an
interpreter command line flag to configure the limit:

   * *note PYTHONINTMAXSTRDIGITS: 18dd, e.g.  ‘PYTHONINTMAXSTRDIGITS=640
     python3’ to set the limit to 640 or ‘PYTHONINTMAXSTRDIGITS=0
     python3’ to disable the limitation.

   * *note -X int_max_str_digits: 176, e.g.  ‘python3 -X
     int_max_str_digits=640’

   * *note sys.flags.int_max_str_digits: 2433. contains the value of
     *note PYTHONINTMAXSTRDIGITS: 18dd. or *note -X int_max_str_digits:
     176.  If both the env var and the ‘-X’ option are set, the ‘-X’
     option takes precedence.  A value of '-1' indicates that both were
     unset, thus a value of *note sys.int_info.default_max_str_digits:
     2434. was used during initialization.

From code, you can inspect the current limit and set a new one using
these *note sys: d9. APIs:

   * *note sys.get_int_max_str_digits(): 1634. and *note
     sys.set_int_max_str_digits(): 18e0. are a getter and setter for the
     interpreter-wide limit.  Subinterpreters have their own limit.

Information about the default and minimum can be found in *note
sys.int_info: 12da.:

   * *note sys.int_info.default_max_str_digits: 12da. is the compiled-in
     default limit.

   * *note sys.int_info.str_digits_check_threshold: 12da. is the lowest
     accepted value for the limit (other than 0 which disables it).

Added in version 3.11.

     Caution: Setting a low limit 'can' lead to problems.  While rare,
     code exists that contains integer constants in decimal in their
     source that exceed the minimum threshold.  A consequence of setting
     the limit is that Python source code containing decimal integer
     literals longer than the limit will encounter an error during
     parsing, usually at startup time or import time or even at
     installation time - anytime an up to date ‘.pyc’ does not already
     exist for the code.  A workaround for source that contains such
     large constants is to convert them to ‘0x’ hexadecimal form as it
     has no limit.

     Test your application thoroughly if you use a low limit.  Ensure
     your tests run with the limit set early via the environment or flag
     so that it applies during startup and even during any installation
     step that may invoke Python to precompile ‘.py’ sources to ‘.pyc’
     files.


File: python.info,  Node: Recommended configuration,  Prev: Configuring the limit,  Up: Integer string conversion length limitation

5.4.16.3 Recommended configuration
..................................

The default *note sys.int_info.default_max_str_digits: 2434. is expected
to be reasonable for most applications.  If your application requires a
different limit, set it from your main entry point using Python version
agnostic code as these APIs were added in security patch releases in
versions before 3.12.

Example:

     >>> import sys
     >>> if hasattr(sys, "set_int_max_str_digits"):
     ...     upper_bound = 68000
     ...     lower_bound = 4004
     ...     current_limit = sys.get_int_max_str_digits()
     ...     if current_limit == 0 or current_limit > upper_bound:
     ...         sys.set_int_max_str_digits(upper_bound)
     ...     elif current_limit < lower_bound:
     ...         sys.set_int_max_str_digits(lower_bound)

If you need to disable it entirely, set it to ‘0’.


File: python.info,  Node: Built-in Exceptions,  Next: Text Processing Services,  Prev: Built-in Types,  Up: The Python Standard Library

5.5 Built-in Exceptions
=======================

In Python, all exceptions must be instances of a class that derives from
*note BaseException: 5be.  In a *note try: 6ec. statement with an *note
except: 18b. clause that mentions a particular class, that clause also
handles any exception classes derived from that class (but not exception
classes from which 'it' is derived).  Two exception classes that are not
related via subclassing are never equivalent, even if they have the same
name.

The built-in exceptions listed in this chapter can be generated by the
interpreter or built-in functions.  Except where mentioned, they have an
“associated value” indicating the detailed cause of the error.  This may
be a string or a tuple of several items of information (e.g., an error
code and a string explaining the code).  The associated value is usually
passed as arguments to the exception class’s constructor.

User code can raise built-in exceptions.  This can be used to test an
exception handler or to report an error condition “just like” the
situation in which the interpreter raises the same exception; but beware
that there is nothing to prevent user code from raising an inappropriate
error.

The built-in exception classes can be subclassed to define new
exceptions; programmers are encouraged to derive new exceptions from the
*note Exception: 9e5. class or one of its subclasses, and not from *note
BaseException: 5be.  More information on defining exceptions is
available in the Python Tutorial under *note User-defined Exceptions:
1e34.

* Menu:

* Exception context::
* Inheriting from built-in exceptions::
* Base classes::
* Concrete exceptions::
* Warnings::
* Exception groups::
* Exception hierarchy::


File: python.info,  Node: Exception context,  Next: Inheriting from built-in exceptions,  Up: Built-in Exceptions

5.5.1 Exception context
-----------------------

Three attributes on exception objects provide information about the
context in which the exception was raised:

 -- Attribute: BaseException.__context__
 -- Attribute: BaseException.__cause__
 -- Attribute: BaseException.__suppress_context__

     When raising a new exception while another exception is already
     being handled, the new exception’s ‘__context__’ attribute is
     automatically set to the handled exception.  An exception may be
     handled when an *note except: 18b. or *note finally: 9d5. clause,
     or a *note with: 5d5. statement, is used.

     This implicit exception context can be supplemented with an
     explicit cause by using ‘from’ with *note raise: 5f0.:

          raise new_exc from original_exc

     The expression following *note from: 5f0. must be an exception or
     ‘None’.  It will be set as ‘__cause__’ on the raised exception.
     Setting ‘__cause__’ also implicitly sets the ‘__suppress_context__’
     attribute to ‘True’, so that using ‘raise new_exc from None’
     effectively replaces the old exception with the new one for display
     purposes (e.g.  converting *note KeyError: 345. to *note
     AttributeError: 34e.), while leaving the old exception available in
     ‘__context__’ for introspection when debugging.

     The default traceback display code shows these chained exceptions
     in addition to the traceback for the exception itself.  An
     explicitly chained exception in ‘__cause__’ is always shown when
     present.  An implicitly chained exception in ‘__context__’ is shown
     only if ‘__cause__’ is *note None: 678. and ‘__suppress_context__’
     is false.

     In either case, the exception itself is always shown after any
     chained exceptions so that the final line of the traceback always
     shows the last exception that was raised.


File: python.info,  Node: Inheriting from built-in exceptions,  Next: Base classes,  Prev: Exception context,  Up: Built-in Exceptions

5.5.2 Inheriting from built-in exceptions
-----------------------------------------

User code can create subclasses that inherit from an exception type.
It’s recommended to only subclass one exception type at a time to avoid
any possible conflicts between how the bases handle the ‘args’
attribute, as well as due to possible memory layout incompatibilities.

'CPython implementation detail:' Most built-in exceptions are
implemented in C for efficiency, see: Objects/exceptions.c(1).  Some
have custom memory layouts which makes it impossible to create a
subclass that inherits from multiple exception types.  The memory layout
of a type is an implementation detail and might change between Python
versions, leading to new conflicts in the future.  Therefore, it’s
recommended to avoid subclassing multiple exception types altogether.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Objects/exceptions.c


File: python.info,  Node: Base classes,  Next: Concrete exceptions,  Prev: Inheriting from built-in exceptions,  Up: Built-in Exceptions

5.5.3 Base classes
------------------

The following exceptions are used mostly as base classes for other
exceptions.

 -- Exception: BaseException

     The base class for all built-in exceptions.  It is not meant to be
     directly inherited by user-defined classes (for that, use *note
     Exception: 9e5.).  If *note str(): 44f. is called on an instance of
     this class, the representation of the argument(s) to the instance
     are returned, or the empty string when there were no arguments.

      -- Attribute: args

          The tuple of arguments given to the exception constructor.
          Some built-in exceptions (like *note OSError: 41a.) expect a
          certain number of arguments and assign a special meaning to
          the elements of this tuple, while others are usually called
          only with a single string giving an error message.

      -- Method: with_traceback (tb)

          This method sets 'tb' as the new traceback for the exception
          and returns the exception object.  It was more commonly used
          before the exception chaining features of PEP 3134(1) became
          available.  The following example shows how we can convert an
          instance of ‘SomeException’ into an instance of
          ‘OtherException’ while preserving the traceback.  Once raised,
          the current frame is pushed onto the traceback of the
          ‘OtherException’, as would have happened to the traceback of
          the original ‘SomeException’ had we allowed it to propagate to
          the caller.

               try:
                   ...
               except SomeException:
                   tb = sys.exception().__traceback__
                   raise OtherException(...).with_traceback(tb)

      -- Attribute: __traceback__

          A writable field that holds the *note traceback object: b0d.
          associated with this exception.  See also: *note The raise
          statement: 5f0.

      -- Method: add_note (note)

          Add the string ‘note’ to the exception’s notes which appear in
          the standard traceback after the exception string.  A *note
          TypeError: 2c3. is raised if ‘note’ is not a string.

          Added in version 3.11.

      -- Attribute: __notes__

          A list of the notes of this exception, which were added with
          *note add_note(): 5bd.  This attribute is created when
          ‘add_note()’ is called.

          Added in version 3.11.

 -- Exception: Exception

     All built-in, non-system-exiting exceptions are derived from this
     class.  All user-defined exceptions should also be derived from
     this class.

 -- Exception: ArithmeticError

     The base class for those built-in exceptions that are raised for
     various arithmetic errors: *note OverflowError: 888, *note
     ZeroDivisionError: 94f, *note FloatingPointError: 243e.

 -- Exception: BufferError

     Raised when a *note buffer: 2e8. related operation cannot be
     performed.

 -- Exception: LookupError

     The base class for the exceptions that are raised when a key or
     index used on a mapping or sequence is invalid: *note IndexError:
     1585, *note KeyError: 345.  This can be raised directly by *note
     codecs.lookup(): 96d.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3134/


File: python.info,  Node: Concrete exceptions,  Next: Warnings,  Prev: Base classes,  Up: Built-in Exceptions

5.5.4 Concrete exceptions
-------------------------

The following exceptions are the exceptions that are usually raised.

 -- Exception: AssertionError

     Raised when an *note assert: 972. statement fails.

 -- Exception: AttributeError

     Raised when an attribute reference (see *note Attribute references:
     2201.) or assignment fails.  (When an object does not support
     attribute references or attribute assignments at all, *note
     TypeError: 2c3. is raised.)

     The optional 'name' and 'obj' keyword-only arguments set the
     corresponding attributes:

      -- Attribute: name

          The name of the attribute that was attempted to be accessed.

      -- Attribute: obj

          The object that was accessed for the named attribute.

     Changed in version 3.10: Added the *note name: 2440. and *note obj:
     2441. attributes.

 -- Exception: EOFError

     Raised when the *note input(): 1320. function hits an end-of-file
     condition (EOF) without reading any data.  (Note: the *note
     io.TextIOBase.read(): 1e24. and *note io.IOBase.readline(): 1373.
     methods return an empty string when they hit EOF.)

 -- Exception: FloatingPointError

     Not currently used.

 -- Exception: GeneratorExit

     Raised when a *note generator: 109f. or *note coroutine: 494. is
     closed; see *note generator.close(): 15df. and *note
     coroutine.close(): 217e.  It directly inherits from *note
     BaseException: 5be. instead of *note Exception: 9e5. since it is
     technically not an error.

 -- Exception: ImportError

     Raised when the *note import: 5e5. statement has troubles trying to
     load a module.  Also raised when the “from list” in ‘from ...
     import’ has a name that cannot be found.

     The optional 'name' and 'path' keyword-only arguments set the
     corresponding attributes:

      -- Attribute: name

          The name of the module that was attempted to be imported.

      -- Attribute: path

          The path to any file which triggered the exception.

     Changed in version 3.3: Added the *note name: 2442. and *note path:
     2443. attributes.

 -- Exception: ModuleNotFoundError

     A subclass of *note ImportError: 41c. which is raised by *note
     import: 5e5. when a module could not be located.  It is also raised
     when ‘None’ is found in *note sys.modules: 1655.

     Added in version 3.6.

 -- Exception: IndexError

     Raised when a sequence subscript is out of range.  (Slice indices
     are silently truncated to fall in the allowed range; if an index is
     not an integer, *note TypeError: 2c3. is raised.)

 -- Exception: KeyError

     Raised when a mapping (dictionary) key is not found in the set of
     existing keys.

 -- Exception: KeyboardInterrupt

     Raised when the user hits the interrupt key (normally ‘Control’-‘C’
     or ‘Delete’).  During execution, a check for interrupts is made
     regularly.  The exception inherits from *note BaseException: 5be.
     so as to not be accidentally caught by code that catches *note
     Exception: 9e5. and thus prevent the interpreter from exiting.

          Note: Catching a ‘KeyboardInterrupt’ requires special
          consideration.  Because it can be raised at unpredictable
          points, it may, in some circumstances, leave the running
          program in an inconsistent state.  It is generally best to
          allow ‘KeyboardInterrupt’ to end the program as quickly as
          possible or avoid raising it entirely.  (See *note Note on
          Signal Handlers and Exceptions: 2444.)

 -- Exception: MemoryError

     Raised when an operation runs out of memory but the situation may
     still be rescued (by deleting some objects).  The associated value
     is a string indicating what kind of (internal) operation ran out of
     memory.  Note that because of the underlying memory management
     architecture (C’s ‘malloc()’ function), the interpreter may not
     always be able to completely recover from this situation; it
     nevertheless raises an exception so that a stack traceback can be
     printed, in case a run-away program was the cause.

 -- Exception: NameError

     Raised when a local or global name is not found.  This applies only
     to unqualified names.  The associated value is an error message
     that includes the name that could not be found.

     The optional 'name' keyword-only argument sets the attribute:

      -- Attribute: name

          The name of the variable that was attempted to be accessed.

     Changed in version 3.10: Added the *note name: 2445. attribute.

 -- Exception: NotImplementedError

     This exception is derived from *note RuntimeError: 195.  In user
     defined base classes, abstract methods should raise this exception
     when they require derived classes to override the method, or while
     the class is being developed to indicate that the real
     implementation still needs to be added.

          Note: It should not be used to indicate that an operator or
          method is not meant to be supported at all – in that case
          either leave the operator / method undefined or, if a
          subclass, set it to *note None: 678.

          Caution: ‘NotImplementedError’ and ‘NotImplemented’ are not
          interchangeable.  This exception should only be used as
          described above; see *note NotImplemented: 7d6. for details on
          correct usage of the built-in constant.

 -- Exception: OSError ([arg])

 -- Exception: OSError (errno, strerror[, filename[, winerror[,
          filename2]]])

     This exception is raised when a system function returns a
     system-related error, including I/O failures such as “file not
     found” or “disk full” (not for illegal argument types or other
     incidental errors).

     The second form of the constructor sets the corresponding
     attributes, described below.  The attributes default to *note None:
     678. if not specified.  For backwards compatibility, if three
     arguments are passed, the *note args: 56f. attribute contains only
     a 2-tuple of the first two constructor arguments.

     The constructor often actually returns a subclass of ‘OSError’, as
     described in *note OS exceptions: 2446. below.  The particular
     subclass depends on the final *note errno: 15fa. value.  This
     behaviour only occurs when constructing ‘OSError’ directly or via
     an alias, and is not inherited when subclassing.

      -- Attribute: errno

          A numeric error code from the C variable ‘errno’.

      -- Attribute: winerror

          Under Windows, this gives you the native Windows error code.
          The *note errno: 15fa. attribute is then an approximate
          translation, in POSIX terms, of that native error code.

          Under Windows, if the 'winerror' constructor argument is an
          integer, the *note errno: 15fa. attribute is determined from
          the Windows error code, and the 'errno' argument is ignored.
          On other platforms, the 'winerror' argument is ignored, and
          the *note winerror: 2447. attribute does not exist.

      -- Attribute: strerror

          The corresponding error message, as provided by the operating
          system.  It is formatted by the C functions ‘perror()’ under
          POSIX, and ‘FormatMessage()’ under Windows.

      -- Attribute: filename
      -- Attribute: filename2

          For exceptions that involve a file system path (such as *note
          open(): 51f. or *note os.unlink(): 1139.), *note filename:
          2449. is the file name passed to the function.  For functions
          that involve two file system paths (such as *note os.rename():
          1135.), *note filename2: 244a. corresponds to the second file
          name passed to the function.

     Changed in version 3.3: *note EnvironmentError: 1091, *note
     IOError: 1090, *note WindowsError: 1092, *note socket.error: 1093,
     *note select.error: 1094. and ‘mmap.error’ have been merged into
     ‘OSError’, and the constructor may return a subclass.

     Changed in version 3.4: The *note filename: 2449. attribute is now
     the original file name passed to the function, instead of the name
     encoded to or decoded from the *note filesystem encoding and error
     handler: 53e.  Also, the 'filename2' constructor argument and
     attribute was added.

 -- Exception: OverflowError

     Raised when the result of an arithmetic operation is too large to
     be represented.  This cannot occur for integers (which would rather
     raise *note MemoryError: 15ab. than give up).  However, for
     historical reasons, OverflowError is sometimes raised for integers
     that are outside a required range.  Because of the lack of
     standardization of floating-point exception handling in C, most
     floating-point operations are not checked.

 -- Exception: PythonFinalizationError

     This exception is derived from *note RuntimeError: 195.  It is
     raised when an operation is blocked during interpreter shutdown
     also known as *note Python finalization: 14e.

     Examples of operations which can be blocked with a
     ‘PythonFinalizationError’ during the Python finalization:

        * Creating a new Python thread.

        * *note os.fork(): 197.

     See also the *note sys.is_finalizing(): a9e. function.

     Added in version 3.13: Previously, a plain *note RuntimeError: 195.
     was raised.

 -- Exception: RecursionError

     This exception is derived from *note RuntimeError: 195.  It is
     raised when the interpreter detects that the maximum recursion
     depth (see *note sys.getrecursionlimit(): 4c7.) is exceeded.

     Added in version 3.5: Previously, a plain *note RuntimeError: 195.
     was raised.

 -- Exception: ReferenceError

     This exception is raised when a weak reference proxy, created by
     the *note weakref.proxy(): a5f. function, is used to access an
     attribute of the referent after it has been garbage collected.  For
     more information on weak references, see the *note weakref: 114.
     module.

 -- Exception: RuntimeError

     Raised when an error is detected that doesn’t fall in any of the
     other categories.  The associated value is a string indicating what
     precisely went wrong.

 -- Exception: StopIteration

     Raised by built-in function *note next(): 7dc. and an *note
     iterator: 1ac.'s *note __next__(): 1315. method to signal that
     there are no further items produced by the iterator.

      -- Attribute: value

          The exception object has a single attribute ‘value’, which is
          given as an argument when constructing the exception, and
          defaults to *note None: 678.

     When a *note generator: 109f. or *note coroutine: 494. function
     returns, a new ‘StopIteration’ instance is raised, and the value
     returned by the function is used as the *note value: 217a.
     parameter to the constructor of the exception.

     If a generator code directly or indirectly raises ‘StopIteration’,
     it is converted into a *note RuntimeError: 195. (retaining the
     ‘StopIteration’ as the new exception’s cause).

     Changed in version 3.3: Added ‘value’ attribute and the ability for
     generator functions to use it to return a value.

     Changed in version 3.5: Introduced the RuntimeError transformation
     via ‘from __future__ import generator_stop’, see PEP 479(1).

     Changed in version 3.7: Enable PEP 479(2) for all code by default:
     a ‘StopIteration’ error raised in a generator is transformed into a
     *note RuntimeError: 195.

 -- Exception: StopAsyncIteration

     Must be raised by *note __anext__(): 1678. method of an *note
     asynchronous iterator: 1ab. object to stop the iteration.

     Added in version 3.5.

 -- Exception: SyntaxError (message, details)

     Raised when the parser encounters a syntax error.  This may occur
     in an *note import: 5e5. statement, in a call to the built-in
     functions *note compile(): 192, *note exec(): 17f, or *note eval():
     180, or when reading the initial script or standard input (also
     interactively).

     The *note str(): 44f. of the exception instance returns only the
     error message.  Details is a tuple whose members are also available
     as separate attributes.

      -- Attribute: filename

          The name of the file the syntax error occurred in.

      -- Attribute: lineno

          Which line number in the file the error occurred in.  This is
          1-indexed: the first line in the file has a ‘lineno’ of 1.

      -- Attribute: offset

          The column in the line where the error occurred.  This is
          1-indexed: the first character in the line has an ‘offset’ of
          1.

      -- Attribute: text

          The source code text involved in the error.

      -- Attribute: end_lineno

          Which line number in the file the error occurred ends in.
          This is 1-indexed: the first line in the file has a ‘lineno’
          of 1.

      -- Attribute: end_offset

          The column in the end line where the error occurred finishes.
          This is 1-indexed: the first character in the line has an
          ‘offset’ of 1.

     For errors in f-string fields, the message is prefixed by
     “f-string: ” and the offsets are offsets in a text constructed from
     the replacement expression.  For example, compiling f’Bad {a b}
     field’ results in this args attribute: (‘f-string: …’, (‘’, 1, 2,
     ‘(a b)n’, 1, 5)).

     Changed in version 3.10: Added the *note end_lineno: 244f. and
     *note end_offset: 2450. attributes.

 -- Exception: IndentationError

     Base class for syntax errors related to incorrect indentation.
     This is a subclass of *note SyntaxError: 18d.

 -- Exception: TabError

     Raised when indentation contains an inconsistent use of tabs and
     spaces.  This is a subclass of *note IndentationError: 7ac.

 -- Exception: SystemError

     Raised when the interpreter finds an internal error, but the
     situation does not look so serious to cause it to abandon all hope.
     The associated value is a string indicating what went wrong (in
     low-level terms).  In *note CPython: 6f9, this could be raised by
     incorrectly using Python’s C API, such as returning a ‘NULL’ value
     without an exception set.

     If you’re confident that this exception wasn’t your fault, or the
     fault of a package you’re using, you should report this to the
     author or maintainer of your Python interpreter.  Be sure to report
     the version of the Python interpreter (‘sys.version’; it is also
     printed at the start of an interactive Python session), the exact
     error message (the exception’s associated value) and if possible
     the source of the program that triggered the error.

 -- Exception: SystemExit

     This exception is raised by the *note sys.exit(): 1394. function.
     It inherits from *note BaseException: 5be. instead of *note
     Exception: 9e5. so that it is not accidentally caught by code that
     catches ‘Exception’.  This allows the exception to properly
     propagate up and cause the interpreter to exit.  When it is not
     handled, the Python interpreter exits; no stack traceback is
     printed.  The constructor accepts the same optional argument passed
     to ‘sys.exit()’.  If the value is an integer, it specifies the
     system exit status (passed to C’s ‘exit()’ function); if it is
     ‘None’, the exit status is zero; if it has another type (such as a
     string), the object’s value is printed and the exit status is one.

     A call to *note sys.exit(): 1394. is translated into an exception
     so that clean-up handlers (*note finally: 9d5. clauses of *note
     try: 6ec. statements) can be executed, and so that a debugger can
     execute a script without running the risk of losing control.  The
     *note os._exit(): 2451. function can be used if it is absolutely
     positively necessary to exit immediately (for example, in the child
     process after a call to *note os.fork(): 197.).

      -- Attribute: code

          The exit status or error message that is passed to the
          constructor.  (Defaults to ‘None’.)

 -- Exception: TypeError

     Raised when an operation or function is applied to an object of
     inappropriate type.  The associated value is a string giving
     details about the type mismatch.

     This exception may be raised by user code to indicate that an
     attempted operation on an object is not supported, and is not meant
     to be.  If an object is meant to support a given operation but has
     not yet provided an implementation, *note NotImplementedError: 228.
     is the proper exception to raise.

     Passing arguments of the wrong type (e.g.  passing a *note list:
     614. when an *note int: 257. is expected) should result in a
     ‘TypeError’, but passing arguments with the wrong value (e.g.  a
     number outside expected boundaries) should result in a *note
     ValueError: 202.

 -- Exception: UnboundLocalError

     Raised when a reference is made to a local variable in a function
     or method, but no value has been bound to that variable.  This is a
     subclass of *note NameError: 442.

 -- Exception: UnicodeError

     Raised when a Unicode-related encoding or decoding error occurs.
     It is a subclass of *note ValueError: 202.

     ‘UnicodeError’ has attributes that describe the encoding or
     decoding error.  For example, ‘err.object[err.start:err.end]’ gives
     the particular invalid input that the codec failed on.

      -- Attribute: encoding

          The name of the encoding that raised the error.

      -- Attribute: reason

          A string describing the specific codec error.

      -- Attribute: object

          The object the codec was attempting to encode or decode.

      -- Attribute: start

          The first index of invalid data in *note object: a9b.

      -- Attribute: end

          The index after the last invalid data in *note object: a9b.

 -- Exception: UnicodeEncodeError

     Raised when a Unicode-related error occurs during encoding.  It is
     a subclass of *note UnicodeError: 12eb.

 -- Exception: UnicodeDecodeError

     Raised when a Unicode-related error occurs during decoding.  It is
     a subclass of *note UnicodeError: 12eb.

 -- Exception: UnicodeTranslateError

     Raised when a Unicode-related error occurs during translating.  It
     is a subclass of *note UnicodeError: 12eb.

 -- Exception: ValueError

     Raised when an operation or function receives an argument that has
     the right type but an inappropriate value, and the situation is not
     described by a more precise exception such as *note IndexError:
     1585.

 -- Exception: ZeroDivisionError

     Raised when the second argument of a division or modulo operation
     is zero.  The associated value is a string indicating the type of
     the operands and the operation.

The following exceptions are kept for compatibility with previous
versions; starting from Python 3.3, they are aliases of *note OSError:
41a.

 -- Exception: EnvironmentError

 -- Exception: IOError

 -- Exception: WindowsError

     Only available on Windows.

* Menu:

* OS exceptions::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0479/

   (2) https://peps.python.org/pep-0479/


File: python.info,  Node: OS exceptions,  Up: Concrete exceptions

5.5.4.1 OS exceptions
.....................

The following exceptions are subclasses of *note OSError: 41a, they get
raised depending on the system error code.

 -- Exception: BlockingIOError

     Raised when an operation would block on an object (e.g.  socket)
     set for non-blocking operation.  Corresponds to ‘errno’ *note
     EAGAIN: 2457, *note EALREADY: 2458, *note EWOULDBLOCK: 2459. and
     *note EINPROGRESS: 245a.

     In addition to those of *note OSError: 41a, ‘BlockingIOError’ can
     have one more attribute:

      -- Attribute: characters_written

          An integer containing the number of 'bytes' written to the
          stream before it blocked.  This attribute is available when
          using the buffered I/O classes from the *note io: 7f. module.

 -- Exception: ChildProcessError

     Raised when an operation on a child process failed.  Corresponds to
     ‘errno’ *note ECHILD: 245c.

 -- Exception: ConnectionError

     A base class for connection-related issues.

     Subclasses are *note BrokenPipeError: 109a, *note
     ConnectionAbortedError: 109b, *note ConnectionRefusedError: 109c.
     and *note ConnectionResetError: 109d.

 -- Exception: BrokenPipeError

     A subclass of *note ConnectionError: e3c, raised when trying to
     write on a pipe while the other end has been closed, or trying to
     write on a socket which has been shutdown for writing.  Corresponds
     to ‘errno’ *note EPIPE: 245d. and *note ESHUTDOWN: 245e.

 -- Exception: ConnectionAbortedError

     A subclass of *note ConnectionError: e3c, raised when a connection
     attempt is aborted by the peer.  Corresponds to ‘errno’ *note
     ECONNABORTED: 245f.

 -- Exception: ConnectionRefusedError

     A subclass of *note ConnectionError: e3c, raised when a connection
     attempt is refused by the peer.  Corresponds to ‘errno’ *note
     ECONNREFUSED: 2460.

 -- Exception: ConnectionResetError

     A subclass of *note ConnectionError: e3c, raised when a connection
     is reset by the peer.  Corresponds to ‘errno’ *note ECONNRESET:
     2461.

 -- Exception: FileExistsError

     Raised when trying to create a file or directory which already
     exists.  Corresponds to ‘errno’ *note EEXIST: 2462.

 -- Exception: FileNotFoundError

     Raised when a file or directory is requested but doesn’t exist.
     Corresponds to ‘errno’ *note ENOENT: 2463.

 -- Exception: InterruptedError

     Raised when a system call is interrupted by an incoming signal.
     Corresponds to ‘errno’ *note EINTR: db5.

     Changed in version 3.5: Python now retries system calls when a
     syscall is interrupted by a signal, except if the signal handler
     raises an exception (see PEP 475(1) for the rationale), instead of
     raising ‘InterruptedError’.

 -- Exception: IsADirectoryError

     Raised when a file operation (such as *note os.remove(): 1134.) is
     requested on a directory.  Corresponds to ‘errno’ *note EISDIR:
     2464.

 -- Exception: NotADirectoryError

     Raised when a directory operation (such as *note os.listdir():
     113e.) is requested on something which is not a directory.  On most
     POSIX platforms, it may also be raised if an operation attempts to
     open or traverse a non-directory file as if it were a directory.
     Corresponds to ‘errno’ *note ENOTDIR: 2465.

 -- Exception: PermissionError

     Raised when trying to run an operation without the adequate access
     rights - for example filesystem permissions.  Corresponds to
     ‘errno’ *note EACCES: 2466, *note EPERM: 18fc, and *note
     ENOTCAPABLE: 18e3.

     Changed in version 3.11.1: WASI’s *note ENOTCAPABLE: 18e3. is now
     mapped to ‘PermissionError’.

 -- Exception: ProcessLookupError

     Raised when a given process doesn’t exist.  Corresponds to ‘errno’
     *note ESRCH: 2467.

 -- Exception: TimeoutError

     Raised when a system function timed out at the system level.
     Corresponds to ‘errno’ *note ETIMEDOUT: 2468.

Added in version 3.3: All the above *note OSError: 41a. subclasses were
added.

See also
........

PEP 3151(2) - Reworking the OS and IO exception hierarchy

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://peps.python.org/pep-3151/


File: python.info,  Node: Warnings,  Next: Exception groups,  Prev: Concrete exceptions,  Up: Built-in Exceptions

5.5.5 Warnings
--------------

The following exceptions are used as warning categories; see the *note
Warning Categories: 246b. documentation for more details.

 -- Exception: Warning

     Base class for warning categories.

 -- Exception: UserWarning

     Base class for warnings generated by user code.

 -- Exception: DeprecationWarning

     Base class for warnings about deprecated features when those
     warnings are intended for other Python developers.

     Ignored by the default warning filters, except in the ‘__main__’
     module ( PEP 565(1)).  Enabling the *note Python Development Mode:
     1f8. shows this warning.

     The deprecation policy is described in PEP 387(2).

 -- Exception: PendingDeprecationWarning

     Base class for warnings about features which are obsolete and
     expected to be deprecated in the future, but are not deprecated at
     the moment.

     This class is rarely used as emitting a warning about a possible
     upcoming deprecation is unusual, and *note DeprecationWarning: 1a5.
     is preferred for already active deprecations.

     Ignored by the default warning filters.  Enabling the *note Python
     Development Mode: 1f8. shows this warning.

     The deprecation policy is described in PEP 387(3).

 -- Exception: SyntaxWarning

     Base class for warnings about dubious syntax.

     This warning is typically emitted when compiling Python source
     code, and usually won’t be reported when running already compiled
     code.

 -- Exception: RuntimeWarning

     Base class for warnings about dubious runtime behavior.

 -- Exception: FutureWarning

     Base class for warnings about deprecated features when those
     warnings are intended for end users of applications that are
     written in Python.

 -- Exception: ImportWarning

     Base class for warnings about probable mistakes in module imports.

     Ignored by the default warning filters.  Enabling the *note Python
     Development Mode: 1f8. shows this warning.

 -- Exception: UnicodeWarning

     Base class for warnings related to Unicode.

 -- Exception: EncodingWarning

     Base class for warnings related to encodings.

     See *note Opt-in EncodingWarning: 1ef8. for details.

     Added in version 3.10.

 -- Exception: BytesWarning

     Base class for warnings related to *note bytes: 1c2. and *note
     bytearray: 2ea.

 -- Exception: ResourceWarning

     Base class for warnings related to resource usage.

     Ignored by the default warning filters.  Enabling the *note Python
     Development Mode: 1f8. shows this warning.

     Added in version 3.2.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0565/

   (2) https://peps.python.org/pep-0387/

   (3) https://peps.python.org/pep-0387/


File: python.info,  Node: Exception groups,  Next: Exception hierarchy,  Prev: Warnings,  Up: Built-in Exceptions

5.5.6 Exception groups
----------------------

The following are used when it is necessary to raise multiple unrelated
exceptions.  They are part of the exception hierarchy so they can be
handled with *note except: 18b. like all other exceptions.  In addition,
they are recognised by *note except*: 5bb, which matches their subgroups
based on the types of the contained exceptions.

 -- Exception: ExceptionGroup (msg, excs)

 -- Exception: BaseExceptionGroup (msg, excs)

     Both of these exception types wrap the exceptions in the sequence
     ‘excs’.  The ‘msg’ parameter must be a string.  The difference
     between the two classes is that ‘BaseExceptionGroup’ extends *note
     BaseException: 5be. and it can wrap any exception, while *note
     ExceptionGroup: 1b6. extends *note Exception: 9e5. and it can only
     wrap subclasses of ‘Exception’.  This design is so that ‘except
     Exception’ catches an ‘ExceptionGroup’ but not
     ‘BaseExceptionGroup’.

     The ‘BaseExceptionGroup’ constructor returns an *note
     ExceptionGroup: 1b6. rather than a ‘BaseExceptionGroup’ if all
     contained exceptions are *note Exception: 9e5. instances, so it can
     be used to make the selection automatic.  The ‘ExceptionGroup’
     constructor, on the other hand, raises a *note TypeError: 2c3. if
     any contained exception is not an ‘Exception’ subclass.

     'CPython implementation detail:' The ‘excs’ parameter may be any
     sequence, but lists and tuples are specifically processed more
     efficiently here.  For optimal performance, pass a tuple as ‘excs’.

      -- Attribute: message

          The ‘msg’ argument to the constructor.  This is a read-only
          attribute.

      -- Attribute: exceptions

          A tuple of the exceptions in the ‘excs’ sequence given to the
          constructor.  This is a read-only attribute.

      -- Method: subgroup (condition)

          Returns an exception group that contains only the exceptions
          from the current group that match 'condition', or ‘None’ if
          the result is empty.

          The condition can be an exception type or tuple of exception
          types, in which case each exception is checked for a match
          using the same check that is used in an ‘except’ clause.  The
          condition can also be a callable (other than a type object)
          that accepts an exception as its single argument and returns
          true for the exceptions that should be in the subgroup.

          The nesting structure of the current exception is preserved in
          the result, as are the values of its *note message: 2470,
          *note __traceback__: 130e, *note __cause__: 1310, *note
          __context__: 130f. and *note __notes__: 243c. fields.  Empty
          nested groups are omitted from the result.

          The condition is checked for all exceptions in the nested
          exception group, including the top-level and any nested
          exception groups.  If the condition is true for such an
          exception group, it is included in the result in full.

          Added in version 3.13: ‘condition’ can be any callable which
          is not a type object.

      -- Method: split (condition)

          Like *note subgroup(): 17d1, but returns the pair ‘(match,
          rest)’ where ‘match’ is ‘subgroup(condition)’ and ‘rest’ is
          the remaining non-matching part.

      -- Method: derive (excs)

          Returns an exception group with the same *note message: 2470,
          but which wraps the exceptions in ‘excs’.

          This method is used by *note subgroup(): 17d1. and *note
          split(): 168f, which are used in various contexts to break up
          an exception group.  A subclass needs to override it in order
          to make ‘subgroup()’ and ‘split()’ return instances of the
          subclass rather than *note ExceptionGroup: 1b6.

          *note subgroup(): 17d1. and *note split(): 168f. copy the
          *note __traceback__: 130e, *note __cause__: 1310, *note
          __context__: 130f. and *note __notes__: 243c. fields from the
          original exception group to the one returned by ‘derive()’, so
          these fields do not need to be updated by ‘derive()’.

               >>> class MyGroup(ExceptionGroup):
               ...     def derive(self, excs):
               ...         return MyGroup(self.message, excs)
               ...
               >>> e = MyGroup("eg", [ValueError(1), TypeError(2)])
               >>> e.add_note("a note")
               >>> e.__context__ = Exception("context")
               >>> e.__cause__ = Exception("cause")
               >>> try:
               ...    raise e
               ... except Exception as e:
               ...    exc = e
               ...
               >>> match, rest = exc.split(ValueError)
               >>> exc, exc.__context__, exc.__cause__, exc.__notes__
               (MyGroup('eg', [ValueError(1), TypeError(2)]), Exception('context'), Exception('cause'), ['a note'])
               >>> match, match.__context__, match.__cause__, match.__notes__
               (MyGroup('eg', [ValueError(1)]), Exception('context'), Exception('cause'), ['a note'])
               >>> rest, rest.__context__, rest.__cause__, rest.__notes__
               (MyGroup('eg', [TypeError(2)]), Exception('context'), Exception('cause'), ['a note'])
               >>> exc.__traceback__ is match.__traceback__ is rest.__traceback__
               True

     Note that ‘BaseExceptionGroup’ defines *note __new__(): 583, so
     subclasses that need a different constructor signature need to
     override that rather than *note __init__(): 6b3.  For example, the
     following defines an exception group subclass which accepts an
     exit_code and constructs the group’s message from it.

          class Errors(ExceptionGroup):
             def __new__(cls, errors, exit_code):
                self = super().__new__(Errors, f"exit code: {exit_code}", errors)
                self.exit_code = exit_code
                return self

             def derive(self, excs):
                return Errors(excs, self.exit_code)

     Like *note ExceptionGroup: 1b6, any subclass of
     ‘BaseExceptionGroup’ which is also a subclass of *note Exception:
     9e5. can only wrap instances of ‘Exception’.

     Added in version 3.11.


File: python.info,  Node: Exception hierarchy,  Prev: Exception groups,  Up: Built-in Exceptions

5.5.7 Exception hierarchy
-------------------------

The class hierarchy for built-in exceptions is:

     BaseException
      ├── BaseExceptionGroup
      ├── GeneratorExit
      ├── KeyboardInterrupt
      ├── SystemExit
      └── Exception
           ├── ArithmeticError
           │    ├── FloatingPointError
           │    ├── OverflowError
           │    └── ZeroDivisionError
           ├── AssertionError
           ├── AttributeError
           ├── BufferError
           ├── EOFError
           ├── ExceptionGroup [BaseExceptionGroup]
           ├── ImportError
           │    └── ModuleNotFoundError
           ├── LookupError
           │    ├── IndexError
           │    └── KeyError
           ├── MemoryError
           ├── NameError
           │    └── UnboundLocalError
           ├── OSError
           │    ├── BlockingIOError
           │    ├── ChildProcessError
           │    ├── ConnectionError
           │    │    ├── BrokenPipeError
           │    │    ├── ConnectionAbortedError
           │    │    ├── ConnectionRefusedError
           │    │    └── ConnectionResetError
           │    ├── FileExistsError
           │    ├── FileNotFoundError
           │    ├── InterruptedError
           │    ├── IsADirectoryError
           │    ├── NotADirectoryError
           │    ├── PermissionError
           │    ├── ProcessLookupError
           │    └── TimeoutError
           ├── ReferenceError
           ├── RuntimeError
           │    ├── NotImplementedError
           │    ├── PythonFinalizationError
           │    └── RecursionError
           ├── StopAsyncIteration
           ├── StopIteration
           ├── SyntaxError
           │    └── IndentationError
           │         └── TabError
           ├── SystemError
           ├── TypeError
           ├── ValueError
           │    └── UnicodeError
           │         ├── UnicodeDecodeError
           │         ├── UnicodeEncodeError
           │         └── UnicodeTranslateError
           └── Warning
                ├── BytesWarning
                ├── DeprecationWarning
                ├── EncodingWarning
                ├── FutureWarning
                ├── ImportWarning
                ├── PendingDeprecationWarning
                ├── ResourceWarning
                ├── RuntimeWarning
                ├── SyntaxWarning
                ├── UnicodeWarning
                └── UserWarning


File: python.info,  Node: Text Processing Services,  Next: Binary Data Services,  Prev: Built-in Exceptions,  Up: The Python Standard Library

5.6 Text Processing Services
============================

The modules described in this chapter provide a wide range of string
manipulation operations and other text processing services.

The *note codecs: 1b. module described under *note Binary Data Services:
2476. is also highly relevant to text processing.  In addition, see the
documentation for Python’s built-in string type in *note Text Sequence
Type — str: 1d92.

* Menu:

* string — Common string operations::
* re — Regular expression operations::
* difflib — Helpers for computing deltas::
* textwrap — Text wrapping and filling::
* unicodedata — Unicode Database::
* stringprep — Internet String Preparation::
* readline — GNU readline interface::
* rlcompleter — Completion function for GNU readline::


File: python.info,  Node: string — Common string operations,  Next: re — Regular expression operations,  Up: Text Processing Services

5.6.1 ‘string’ — Common string operations
-----------------------------------------

'Source code:' Lib/string.py(1)

__________________________________________________________________

See also
........

*note Text Sequence Type — str: 1d92.

*note String Methods: 1d93.

* Menu:

* String constants::
* Custom string formatting::
* Format string syntax::
* Template strings::
* Helper functions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/string.py


File: python.info,  Node: String constants,  Next: Custom string formatting,  Up: string — Common string operations

5.6.1.1 String constants
........................

The constants defined in this module are:

 -- Data: string.ascii_letters

     The concatenation of the *note ascii_lowercase: 247a. and *note
     ascii_uppercase: 247b. constants described below.  This value is
     not locale-dependent.

 -- Data: string.ascii_lowercase

     The lowercase letters ‘'abcdefghijklmnopqrstuvwxyz'’.  This value
     is not locale-dependent and will not change.

 -- Data: string.ascii_uppercase

     The uppercase letters ‘'ABCDEFGHIJKLMNOPQRSTUVWXYZ'’.  This value
     is not locale-dependent and will not change.

 -- Data: string.digits

     The string ‘'0123456789'’.

 -- Data: string.hexdigits

     The string ‘'0123456789abcdefABCDEF'’.

 -- Data: string.octdigits

     The string ‘'01234567'’.

 -- Data: string.punctuation

     String of ASCII characters which are considered punctuation
     characters in the ‘C’ locale: ‘!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~’.

 -- Data: string.printable

     String of ASCII characters which are considered printable by
     Python.  This is a combination of *note digits: 247c, *note
     ascii_letters: 130b, *note punctuation: 247f, and *note whitespace:
     2480.

          Note: By design, *note string.printable.isprintable(): e08.
          returns *note False: b4f.  In particular, ‘string.printable’
          is not printable in the POSIX sense (see ‘LC_CTYPE(1)’).

 -- Data: string.whitespace

     A string containing all ASCII characters that are considered
     whitespace.  This includes the characters space, tab, linefeed,
     return, formfeed, and vertical tab.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/locale(5)


File: python.info,  Node: Custom string formatting,  Next: Format string syntax,  Prev: String constants,  Up: string — Common string operations

5.6.1.2 Custom string formatting
................................

The built-in string class provides the ability to do complex variable
substitutions and value formatting via the *note format(): 624. method
described in PEP 3101(1).  The *note Formatter: ef1. class in the
‘string’ module allows you to create and customize your own string
formatting behaviors using the same implementation as the built-in
‘format()’ method.

 -- Class: string.Formatter

     The ‘Formatter’ class has the following public methods:

      -- Method: format (format_string, /, *args, **kwargs)

          The primary API method.  It takes a format string and an
          arbitrary set of positional and keyword arguments.  It is just
          a wrapper that calls *note vformat(): 2482.

          Changed in version 3.7: A format string argument is now *note
          positional-only: a94.

      -- Method: vformat (format_string, args, kwargs)

          This function does the actual work of formatting.  It is
          exposed as a separate function for cases where you want to
          pass in a predefined dictionary of arguments, rather than
          unpacking and repacking the dictionary as individual arguments
          using the ‘*args’ and ‘**kwargs’ syntax.  ‘vformat()’ does the
          work of breaking up the format string into character data and
          replacement fields.  It calls the various methods described
          below.

     In addition, the ‘Formatter’ defines a number of methods that are
     intended to be replaced by subclasses:

      -- Method: parse (format_string)

          Loop over the format_string and return an iterable of tuples
          ('literal_text', 'field_name', 'format_spec', 'conversion').
          This is used by *note vformat(): 2482. to break the string
          into either literal text, or replacement fields.

          The values in the tuple conceptually represent a span of
          literal text followed by a single replacement field.  If there
          is no literal text (which can happen if two replacement fields
          occur consecutively), then 'literal_text' will be a
          zero-length string.  If there is no replacement field, then
          the values of 'field_name', 'format_spec' and 'conversion'
          will be ‘None’.

      -- Method: get_field (field_name, args, kwargs)

          Given 'field_name' as returned by *note parse(): 2483. (see
          above), convert it to an object to be formatted.  Returns a
          tuple (obj, used_key).  The default version takes strings of
          the form defined in PEP 3101(2), such as “0[name]” or
          “label.title”.  'args' and 'kwargs' are as passed in to *note
          vformat(): 2482.  The return value 'used_key' has the same
          meaning as the 'key' parameter to *note get_value(): 2485.

      -- Method: get_value (key, args, kwargs)

          Retrieve a given field value.  The 'key' argument will be
          either an integer or a string.  If it is an integer, it
          represents the index of the positional argument in 'args'; if
          it is a string, then it represents a named argument in
          'kwargs'.

          The 'args' parameter is set to the list of positional
          arguments to *note vformat(): 2482, and the 'kwargs' parameter
          is set to the dictionary of keyword arguments.

          For compound field names, these functions are only called for
          the first component of the field name; subsequent components
          are handled through normal attribute and indexing operations.

          So for example, the field expression ‘0.name’ would cause
          ‘get_value()’ to be called with a 'key' argument of 0.  The
          ‘name’ attribute will be looked up after ‘get_value()’ returns
          by calling the built-in *note getattr(): bf0. function.

          If the index or keyword refers to an item that does not exist,
          then an *note IndexError: 1585. or *note KeyError: 345. should
          be raised.

      -- Method: check_unused_args (used_args, args, kwargs)

          Implement checking for unused arguments if desired.  The
          arguments to this function is the set of all argument keys
          that were actually referred to in the format string (integers
          for positional arguments, and strings for named arguments),
          and a reference to the 'args' and 'kwargs' that was passed to
          vformat.  The set of unused args can be calculated from these
          parameters.  ‘check_unused_args()’ is assumed to raise an
          exception if the check fails.

      -- Method: format_field (value, format_spec)

          ‘format_field()’ simply calls the global *note format(): 622.
          built-in.  The method is provided so that subclasses can
          override it.

      -- Method: convert_field (value, conversion)

          Converts the value (returned by *note get_field(): 2484.)
          given a conversion type (as in the tuple returned by the *note
          parse(): 2483. method).  The default version understands ‘s’
          (str), ‘r’ (repr) and ‘a’ (ascii) conversion types.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3101/

   (2) https://peps.python.org/pep-3101/


File: python.info,  Node: Format string syntax,  Next: Template strings,  Prev: Custom string formatting,  Up: string — Common string operations

5.6.1.3 Format string syntax
............................

The *note str.format(): 624. method and the *note Formatter: ef1. class
share the same syntax for format strings (although in the case of
‘Formatter’, subclasses can define their own format string syntax).  The
syntax is related to that of *note formatted string literals: 9b4, but
it is less sophisticated and, in particular, does not support arbitrary
expressions.

Format strings contain “replacement fields” surrounded by curly braces
‘{}’.  Anything that is not contained in braces is considered literal
text, which is copied unchanged to the output.  If you need to include a
brace character in the literal text, it can be escaped by doubling: ‘{{’
and ‘}}’.

The grammar for a replacement field is as follows:

     replacement_field ::= "{" [*note field_name: 248b.] ["!" *note conversion: 248c.] [":" *note format_spec: 248d.] "}"
     field_name        ::= *note arg_name: 248e. ("." *note attribute_name: 248f. | "[" *note element_index: 2490. "]")*
     arg_name          ::= [*note identifier: 2042. | *note digit: 207b.+]
     attribute_name    ::= *note identifier: 2042.
     element_index     ::= *note digit: 207b.+ | *note index_string: 2491.
     index_string      ::= <any source character except "]"> +
     conversion        ::= "r" | "s" | "a"
     format_spec       ::= *note format-spec;format_spec: 2492.

In less formal terms, the replacement field can start with a
'field_name' that specifies the object whose value is to be formatted
and inserted into the output instead of the replacement field.  The
'field_name' is optionally followed by a 'conversion' field, which is
preceded by an exclamation point ‘'!'’, and a 'format_spec', which is
preceded by a colon ‘':'’.  These specify a non-default format for the
replacement value.

See also the *note Format specification mini-language: 1e8. section.

The 'field_name' itself begins with an 'arg_name' that is either a
number or a keyword.  If it’s a number, it refers to a positional
argument, and if it’s a keyword, it refers to a named keyword argument.
An 'arg_name' is treated as a number if a call to *note str.isdecimal():
237d. on the string would return true.  If the numerical arg_names in a
format string are 0, 1, 2, … in sequence, they can all be omitted (not
just some) and the numbers 0, 1, 2, … will be automatically inserted in
that order.  Because 'arg_name' is not quote-delimited, it is not
possible to specify arbitrary dictionary keys (e.g., the strings ‘'10'’
or ‘':-]'’) within a format string.  The 'arg_name' can be followed by
any number of index or attribute expressions.  An expression of the form
‘'.name'’ selects the named attribute using *note getattr(): bf0, while
an expression of the form ‘'[index]'’ does an index lookup using *note
__getitem__(): 283.

Changed in version 3.1: The positional argument specifiers can be
omitted for *note str.format(): 624, so ‘'{} {}'.format(a, b)’ is
equivalent to ‘'{0} {1}'.format(a, b)’.

Changed in version 3.4: The positional argument specifiers can be
omitted for *note Formatter: ef1.

Some simple format string examples:

     "First, thou shalt count to {0}"  # References first positional argument
     "Bring me a {}"                   # Implicitly references the first positional argument
     "From {} to {}"                   # Same as "From {0} to {1}"
     "My quest is {name}"              # References keyword argument 'name'
     "Weight in tons {0.weight}"       # 'weight' attribute of first positional arg
     "Units destroyed: {players[0]}"   # First element of keyword argument 'players'.

The 'conversion' field causes a type coercion before formatting.
Normally, the job of formatting a value is done by the *note
__format__(): 621. method of the value itself.  However, in some cases
it is desirable to force a type to be formatted as a string, overriding
its own definition of formatting.  By converting the value to a string
before calling ‘__format__()’, the normal formatting logic is bypassed.

Three conversion flags are currently supported: ‘'!s'’ which calls *note
str(): 44f. on the value, ‘'!r'’ which calls *note repr(): 803. and
‘'!a'’ which calls *note ascii(): 1434.

Some examples:

     "Harold's a clever {0!s}"        # Calls str() on the argument first
     "Bring out the holy {name!r}"    # Calls repr() on the argument first
     "More {!a}"                      # Calls ascii() on the argument first

The 'format_spec' field contains a specification of how the value should
be presented, including such details as field width, alignment, padding,
decimal precision and so on.  Each value type can define its own
“formatting mini-language” or interpretation of the 'format_spec'.

Most built-in types support a common formatting mini-language, which is
described in the next section.

A 'format_spec' field can also include nested replacement fields within
it.  These nested replacement fields may contain a field name,
conversion flag and format specification, but deeper nesting is not
allowed.  The replacement fields within the format_spec are substituted
before the 'format_spec' string is interpreted.  This allows the
formatting of a value to be dynamically specified.

See the *note Format examples: 2493. section for some examples.

* Menu:

* Format specification mini-language::
* Format examples::


File: python.info,  Node: Format specification mini-language,  Next: Format examples,  Up: Format string syntax

5.6.1.4 Format specification mini-language
..........................................

“Format specifications” are used within replacement fields contained
within a format string to define how individual values are presented
(see *note Format string syntax: 13e8. and *note f-strings: 9b4.).  They
can also be passed directly to the built-in *note format(): 622.
function.  Each formattable type may define how the format specification
is to be interpreted.

Most built-in types implement the following options for format
specifications, although some of the formatting options are only
supported by the numeric types.

A general convention is that an empty format specification produces the
same result as if you had called *note str(): 44f. on the value.  A
non-empty format specification typically modifies the result.

The general form of a 'standard format specifier' is:

     format_spec ::= [*note options: 2495.][*note width: 2496.][*note grouping: 2497.]["." *note precision: 2498.][*note type: 2499.]
     options     ::= [[*note fill: 249a.]*note align: 249b.][*note sign: 249c.]["z"]["#"]["0"]
     fill        ::= <any character>
     align       ::= "<" | ">" | "=" | "^"
     sign        ::= "+" | "-" | " "
     width       ::= *note digit: 207b.+
     grouping    ::= "," | "_"
     precision   ::= *note digit: 207b.+
     type        ::= "b" | "c" | "d" | "e" | "E" | "f" | "F" | "g"
                     | "G" | "n" | "o" | "s" | "x" | "X" | "%"

If a valid 'align' value is specified, it can be preceded by a 'fill'
character that can be any character and defaults to a space if omitted.
It is not possible to use a literal curly brace (”‘{’” or “‘}’”) as the
'fill' character in a *note formatted string literal: 9b4. or when using
the *note str.format(): 624. method.  However, it is possible to insert
a curly brace with a nested replacement field.  This limitation doesn’t
affect the *note format(): 622. function.

The meaning of the various alignment options is as follows:

Option        Meaning
              
-----------------------------------------------------------------------------
              
‘'<'’         Forces the field to be left-aligned within the available
              space (this is the default for most objects).
              
              
‘'>'’         Forces the field to be right-aligned within the available
              space (this is the default for numbers).
              
              
‘'='’         Forces the padding to be placed after the sign (if any) but
              before the digits.  This is used for printing fields in the
              form ‘+000000120’.  This alignment option is only valid for
              numeric types, excluding *note complex: 2f8.  It becomes the
              default for numbers when ‘0’ immediately precedes the field
              width.
              
              
‘'^'’         Forces the field to be centered within the available space.
              

Note that unless a minimum field width is defined, the field width will
always be the same size as the data to fill it, so that the alignment
option has no meaning in this case.

The 'sign' option is only valid for number types, and can be one of the
following:

Option        Meaning
              
-----------------------------------------------------------------------------
              
‘'+'’         Indicates that a sign should be used for both positive as
              well as negative numbers.
              
              
‘'-'’         Indicates that a sign should be used only for negative
              numbers (this is the default behavior).
              
              
space         Indicates that a leading space should be used on positive
              numbers, and a minus sign on negative numbers.
              

The ‘'z'’ option coerces negative zero floating-point values to positive
zero after rounding to the format precision.  This option is only valid
for floating-point presentation types.

Changed in version 3.11: Added the ‘'z'’ option (see also PEP 682(1)).

The ‘'#'’ option causes the “alternate form” to be used for the
conversion.  The alternate form is defined differently for different
types.  This option is only valid for integer, float and complex types.
For integers, when binary, octal, or hexadecimal output is used, this
option adds the respective prefix ‘'0b'’, ‘'0o'’, ‘'0x'’, or ‘'0X'’ to
the output value.  For float and complex the alternate form causes the
result of the conversion to always contain a decimal-point character,
even if no digits follow it.  Normally, a decimal-point character
appears in the result of these conversions only if a digit follows it.
In addition, for ‘'g'’ and ‘'G'’ conversions, trailing zeros are not
removed from the result.

The 'width' is a decimal integer defining the minimum total field width,
including any prefixes, separators, and other formatting characters.  If
not specified, then the field width will be determined by the content.

When no explicit alignment is given, preceding the 'width' field by a
zero (‘'0'’) character enables sign-aware zero-padding for numeric
types, excluding *note complex: 2f8.  This is equivalent to a 'fill'
character of ‘'0'’ with an 'alignment' type of ‘'='’.

Changed in version 3.10: Preceding the 'width' field by ‘'0'’ no longer
affects the default alignment for strings.

The 'grouping' option after the 'width' field specifies a digit group
separator for the integral part of a number.  It can be one of the
following:

Option        Meaning
              
-----------------------------------------------------------------------------
              
‘','’         Inserts a comma every 3 digits for integer presentation type
              ‘'d'’ and floating-point presentation types, excluding
              ‘'n'’.  For other presentation types, this option is not
              supported.
              
              
‘'_'’         Inserts an underscore every 3 digits for integer
              presentation type ‘'d'’ and floating-point presentation
              types, excluding ‘'n'’.  For integer presentation types
              ‘'b'’, ‘'o'’, ‘'x'’, and ‘'X'’, underscores are inserted
              every 4 digits.  For other presentation types, this option
              is not supported.
              

For a locale aware separator, use the ‘'n'’ presentation type instead.

Changed in version 3.1: Added the ‘','’ option (see also PEP 378(2)).

Changed in version 3.6: Added the ‘'_'’ option (see also PEP 515(3)).

The 'precision' is a decimal integer indicating how many digits should
be displayed after the decimal point for presentation types ‘'f'’ and
‘'F'’, or before and after the decimal point for presentation types
‘'g'’ or ‘'G'’.  For string presentation types the field indicates the
maximum field size - in other words, how many characters will be used
from the field content.  The 'precision' is not allowed for integer
presentation types.

Finally, the 'type' determines how the data should be presented.

The available string presentation types are:

     Type          Meaning
                   
     -----------------------------------------------------------------------------
                   
     ‘'s'’         String format.  This is the default type for strings and may
                   be omitted.
                   
                   
     None          The same as ‘'s'’.
                   

The available integer presentation types are:

     Type          Meaning
                   
     -----------------------------------------------------------------------------
                   
     ‘'b'’         Binary format.  Outputs the number in base 2.
                   
                   
     ‘'c'’         Character.  Converts the integer to the corresponding
                   unicode character before printing.
                   
                   
     ‘'d'’         Decimal Integer.  Outputs the number in base 10.
                   
                   
     ‘'o'’         Octal format.  Outputs the number in base 8.
                   
                   
     ‘'x'’         Hex format.  Outputs the number in base 16, using lower-case
                   letters for the digits above 9.
                   
                   
     ‘'X'’         Hex format.  Outputs the number in base 16, using upper-case
                   letters for the digits above 9.  In case ‘'#'’ is specified,
                   the prefix ‘'0x'’ will be upper-cased to ‘'0X'’ as well.
                   
                   
     ‘'n'’         Number.  This is the same as ‘'d'’, except that it uses the
                   current locale setting to insert the appropriate digit group
                   separators.
                   
                   
     None          The same as ‘'d'’.
                   

In addition to the above presentation types, integers can be formatted
with the floating-point presentation types listed below (except ‘'n'’
and ‘None’).  When doing so, *note float(): 2f7. is used to convert the
integer to a floating-point number before formatting.

The available presentation types for *note float: 2f7. and *note
Decimal: 29d. values are:

     Type          Meaning
                   
     -----------------------------------------------------------------------------
                   
     ‘'e'’         Scientific notation.  For a given precision ‘p’, formats the
                   number in scientific notation with the letter ‘e’ separating
                   the coefficient from the exponent.  The coefficient has one
                   digit before and ‘p’ digits after the decimal point, for a
                   total of ‘p + 1’ significant digits.  With no precision
                   given, uses a precision of ‘6’ digits after the decimal
                   point for *note float: 2f7, and shows all coefficient digits
                   for *note Decimal: 29d.  If ‘p=0’, the decimal point is
                   omitted unless the ‘#’ option is used.
                   
                   For *note float: 2f7, the exponent always contains at least
                   two digits, and is zero if the value is zero.
                   
                   
     ‘'E'’         Scientific notation.  Same as ‘'e'’ except it uses an upper
                   case ‘E’ as the separator character.
                   
                   
     ‘'f'’         Fixed-point notation.  For a given precision ‘p’, formats
                   the number as a decimal number with exactly ‘p’ digits
                   following the decimal point.  With no precision given, uses
                   a precision of ‘6’ digits after the decimal point for
                   *note float: 2f7, and uses a precision large enough to show
                   all coefficient digits for *note Decimal: 29d.  If ‘p=0’,
                   the decimal point is omitted unless the ‘#’ option is used.
                   
                   
     ‘'F'’         Fixed-point notation.  Same as ‘'f'’, but converts ‘nan’ to
                   ‘NAN’ and ‘inf’ to ‘INF’.
                   
                   
     ‘'g'’         General format.  For a given precision ‘p >= 1’, this rounds
                   the number to ‘p’ significant digits and then formats the
                   result in either fixed-point format or in scientific
                   notation, depending on its magnitude.  A precision of ‘0’ is
                   treated as equivalent to a precision of ‘1’.
                   
                   The precise rules are as follows: suppose that the result
                   formatted with presentation type ‘'e'’ and precision ‘p-1’
                   would have exponent ‘exp’.  Then, if ‘m <= exp < p’, where
                   ‘m’ is -4 for floats and -6 for *note Decimals: 29d, the
                   number is formatted with presentation type ‘'f'’ and
                   precision ‘p-1-exp’.  Otherwise, the number is formatted
                   with presentation type ‘'e'’ and precision ‘p-1’.  In both
                   cases insignificant trailing zeros are removed from the
                   significand, and the decimal point is also removed if there
                   are no remaining digits following it, unless the ‘'#'’
                   option is used.
                   
                   With no precision given, uses a precision of ‘6’ significant
                   digits for *note float: 2f7.  For *note Decimal: 29d, the
                   coefficient of the result is formed from the coefficient
                   digits of the value; scientific notation is used for values
                   smaller than ‘1e-6’ in absolute value and values where the
                   place value of the least significant digit is larger than 1,
                   and fixed-point notation is used otherwise.
                   
                   Positive and negative infinity, positive and negative zero,
                   and nans, are formatted as ‘inf’, ‘-inf’, ‘0’, ‘-0’ and
                   ‘nan’ respectively, regardless of the precision.
                   
                   
     ‘'G'’         General format.  Same as ‘'g'’ except switches to ‘'E'’ if
                   the number gets too large.  The representations of infinity
                   and NaN are uppercased, too.
                   
                   
     ‘'n'’         Number.  This is the same as ‘'g'’, except that it uses the
                   current locale setting to insert the appropriate digit group
                   separators for the integral part of a number.
                   
                   
     ‘'%'’         Percentage.  Multiplies the number by 100 and displays in
                   fixed (‘'f'’) format, followed by a percent sign.
                   
                   
     None          For *note float: 2f7. this is like the ‘'g'’ type, except
                   that when fixed-point notation is used to format the result,
                   it always includes at least one digit past the decimal
                   point, and switches to the scientific notation when ‘exp >=
                   p - 1’.  When the precision is not specified, the latter
                   will be as large as needed to represent the given value
                   faithfully.
                   
                   For *note Decimal: 29d, this is the same as either ‘'g'’ or
                   ‘'G'’ depending on the value of ‘context.capitals’ for the
                   current decimal context.
                   
                   The overall effect is to match the output of
                   *note str(): 44f. as altered by the other format modifiers.
                   

The result should be correctly rounded to a given precision ‘p’ of
digits after the decimal point.  The rounding mode for *note float: 2f7.
matches that of the *note round(): 1322. builtin.  For *note Decimal:
29d, the rounding mode of the current *note context: 249d. will be used.

The available presentation types for *note complex: 2f8. are the same as
those for *note float: 2f7. (‘'%'’ is not allowed).  Both the real and
imaginary components of a complex number are formatted as floating-point
numbers, according to the specified presentation type.  They are
separated by the mandatory sign of the imaginary part, the latter being
terminated by a ‘j’ suffix.  If the presentation type is missing, the
result will match the output of *note str(): 44f. (complex numbers with
a non-zero real part are also surrounded by parentheses), possibly
altered by other format modifiers.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0682/

   (2) https://peps.python.org/pep-0378/

   (3) https://peps.python.org/pep-0515/


File: python.info,  Node: Format examples,  Prev: Format specification mini-language,  Up: Format string syntax

5.6.1.5 Format examples
.......................

This section contains examples of the *note str.format(): 624. syntax
and comparison with the old ‘%’-formatting.

In most of the cases the syntax is similar to the old ‘%’-formatting,
with the addition of the ‘{}’ and with ‘:’ used instead of ‘%’.  For
example, ‘'%03.2f'’ can be translated to ‘'{:03.2f}'’.

The new format syntax also supports new and different options, shown in
the following examples.

Accessing arguments by position:

     >>> '{0}, {1}, {2}'.format('a', 'b', 'c')
     'a, b, c'
     >>> '{}, {}, {}'.format('a', 'b', 'c')  # 3.1+ only
     'a, b, c'
     >>> '{2}, {1}, {0}'.format('a', 'b', 'c')
     'c, b, a'
     >>> '{2}, {1}, {0}'.format(*'abc')      # unpacking argument sequence
     'c, b, a'
     >>> '{0}{1}{0}'.format('abra', 'cad')   # arguments' indices can be repeated
     'abracadabra'

Accessing arguments by name:

     >>> 'Coordinates: {latitude}, {longitude}'.format(latitude='37.24N', longitude='-115.81W')
     'Coordinates: 37.24N, -115.81W'
     >>> coord = {'latitude': '37.24N', 'longitude': '-115.81W'}
     >>> 'Coordinates: {latitude}, {longitude}'.format(**coord)
     'Coordinates: 37.24N, -115.81W'

Accessing arguments’ attributes:

     >>> c = 3-5j
     >>> ('The complex number {0} is formed from the real part {0.real} '
     ...  'and the imaginary part {0.imag}.').format(c)
     'The complex number (3-5j) is formed from the real part 3.0 and the imaginary part -5.0.'
     >>> class Point:
     ...     def __init__(self, x, y):
     ...         self.x, self.y = x, y
     ...     def __str__(self):
     ...         return 'Point({self.x}, {self.y})'.format(self=self)
     ...
     >>> str(Point(4, 2))
     'Point(4, 2)'

Accessing arguments’ items:

     >>> coord = (3, 5)
     >>> 'X: {0[0]};  Y: {0[1]}'.format(coord)
     'X: 3;  Y: 5'

Replacing ‘%s’ and ‘%r’:

     >>> "repr() shows quotes: {!r}; str() doesn't: {!s}".format('test1', 'test2')
     "repr() shows quotes: 'test1'; str() doesn't: test2"

Aligning the text and specifying a width:

     >>> '{:<30}'.format('left aligned')
     'left aligned                  '
     >>> '{:>30}'.format('right aligned')
     '                 right aligned'
     >>> '{:^30}'.format('centered')
     '           centered           '
     >>> '{:*^30}'.format('centered')  # use '*' as a fill char
     '***********centered***********'

Replacing ‘%+f’, ‘%-f’, and ‘% f’ and specifying a sign:

     >>> '{:+f}; {:+f}'.format(3.14, -3.14)  # show it always
     '+3.140000; -3.140000'
     >>> '{: f}; {: f}'.format(3.14, -3.14)  # show a space for positive numbers
     ' 3.140000; -3.140000'
     >>> '{:-f}; {:-f}'.format(3.14, -3.14)  # show only the minus -- same as '{:f}; {:f}'
     '3.140000; -3.140000'

Replacing ‘%x’ and ‘%o’ and converting the value to different bases:

     >>> # format also supports binary numbers
     >>> "int: {0:d};  hex: {0:x};  oct: {0:o};  bin: {0:b}".format(42)
     'int: 42;  hex: 2a;  oct: 52;  bin: 101010'
     >>> # with 0x, 0o, or 0b as prefix:
     >>> "int: {0:d};  hex: {0:#x};  oct: {0:#o};  bin: {0:#b}".format(42)
     'int: 42;  hex: 0x2a;  oct: 0o52;  bin: 0b101010'

Using the comma or the underscore as a digit group separator:

     >>> '{:,}'.format(1234567890)
     '1,234,567,890'
     >>> '{:_}'.format(1234567890)
     '1_234_567_890'
     >>> '{:_b}'.format(1234567890)
     '100_1001_1001_0110_0000_0010_1101_0010'
     >>> '{:_x}'.format(1234567890)
     '4996_02d2'

Expressing a percentage:

     >>> points = 19
     >>> total = 22
     >>> 'Correct answers: {:.2%}'.format(points/total)
     'Correct answers: 86.36%'

Using type-specific formatting:

     >>> import datetime as dt
     >>> d = dt.datetime(2010, 7, 4, 12, 15, 58)
     >>> '{:%Y-%m-%d %H:%M:%S}'.format(d)
     '2010-07-04 12:15:58'

Nesting arguments and more complex examples:

     >>> for align, text in zip('<^>', ['left', 'center', 'right']):
     ...     '{0:{fill}{align}16}'.format(text, fill=align, align=align)
     ...
     'left<<<<<<<<<<<<'
     '^^^^^center^^^^^'
     '>>>>>>>>>>>right'
     >>>
     >>> octets = [192, 168, 0, 1]
     >>> '{:02X}{:02X}{:02X}{:02X}'.format(*octets)
     'C0A80001'
     >>> int(_, 16)
     3232235521
     >>>
     >>> width = 5
     >>> for num in range(5,12):
     ...     for base in 'dXob':
     ...         print('{0:{width}{base}}'.format(num, base=base, width=width), end=' ')
     ...     print()
     ...
         5     5     5   101
         6     6     6   110
         7     7     7   111
         8     8    10  1000
         9     9    11  1001
        10     A    12  1010
        11     B    13  1011


File: python.info,  Node: Template strings,  Next: Helper functions,  Prev: Format string syntax,  Up: string — Common string operations

5.6.1.6 Template strings
........................

Template strings provide simpler string substitutions as described in
PEP 292(1).  A primary use case for template strings is for
internationalization (i18n) since in that context, the simpler syntax
and functionality makes it easier to translate than other built-in
string formatting facilities in Python.  As an example of a library
built on template strings for i18n, see the flufl.i18n(2) package.

Template strings support ‘$’-based substitutions, using the following
rules:

   * ‘$$’ is an escape; it is replaced with a single ‘$’.

   * ‘$identifier’ names a substitution placeholder matching a mapping
     key of ‘"identifier"’.  By default, ‘"identifier"’ is restricted to
     any case-insensitive ASCII alphanumeric string (including
     underscores) that starts with an underscore or ASCII letter.  The
     first non-identifier character after the ‘$’ character terminates
     this placeholder specification.

   * ‘${identifier}’ is equivalent to ‘$identifier’.  It is required
     when valid identifier characters follow the placeholder but are not
     part of the placeholder, such as ‘"${noun}ification"’.

Any other appearance of ‘$’ in the string will result in a *note
ValueError: 202. being raised.

The ‘string’ module provides a *note Template: 68a. class that
implements these rules.  The methods of ‘Template’ are:

 -- Class: string.Template (template)

     The constructor takes a single argument which is the template
     string.

      -- Method: substitute (mapping={}, /, **kwds)

          Performs the template substitution, returning a new string.
          'mapping' is any dictionary-like object with keys that match
          the placeholders in the template.  Alternatively, you can
          provide keyword arguments, where the keywords are the
          placeholders.  When both 'mapping' and 'kwds' are given and
          there are duplicates, the placeholders from 'kwds' take
          precedence.

      -- Method: safe_substitute (mapping={}, /, **kwds)

          Like *note substitute(): 1e8d, except that if placeholders are
          missing from 'mapping' and 'kwds', instead of raising a *note
          KeyError: 345. exception, the original placeholder will appear
          in the resulting string intact.  Also, unlike with
          ‘substitute()’, any other appearances of the ‘$’ will simply
          return ‘$’ instead of raising *note ValueError: 202.

          While other exceptions may still occur, this method is called
          “safe” because it always tries to return a usable string
          instead of raising an exception.  In another sense,
          ‘safe_substitute()’ may be anything other than safe, since it
          will silently ignore malformed templates containing dangling
          delimiters, unmatched braces, or placeholders that are not
          valid Python identifiers.

      -- Method: is_valid ()

          Returns ‘False’ if the template has invalid placeholders that
          will cause *note substitute(): 1e8d. to raise *note
          ValueError: 202.

          Added in version 3.11.

      -- Method: get_identifiers ()

          Returns a list of the valid identifiers in the template, in
          the order they first appear, ignoring any invalid identifiers.

          Added in version 3.11.

     ‘Template’ instances also provide one public data attribute:

      -- Attribute: template

          This is the object passed to the constructor’s 'template'
          argument.  In general, you shouldn’t change it, but read-only
          access is not enforced.

Here is an example of how to use a Template:

     >>> from string import Template
     >>> s = Template('$who likes $what')
     >>> s.substitute(who='tim', what='kung pao')
     'tim likes kung pao'
     >>> d = dict(who='tim')
     >>> Template('Give $who $100').substitute(d)
     Traceback (most recent call last):
     ...
     ValueError: Invalid placeholder in string: line 1, col 11
     >>> Template('$who likes $what').substitute(d)
     Traceback (most recent call last):
     ...
     KeyError: 'what'
     >>> Template('$who likes $what').safe_substitute(d)
     'tim likes $what'

Advanced usage: you can derive subclasses of *note Template: 68a. to
customize the placeholder syntax, delimiter character, or the entire
regular expression used to parse template strings.  To do this, you can
override these class attributes:

   * 'delimiter' – This is the literal string describing a placeholder
     introducing delimiter.  The default value is ‘$’.  Note that this
     should 'not' be a regular expression, as the implementation will
     call *note re.escape(): c29. on this string as needed.  Note
     further that you cannot change the delimiter after class creation
     (i.e.  a different delimiter must be set in the subclass’s class
     namespace).

   * 'idpattern' – This is the regular expression describing the pattern
     for non-braced placeholders.  The default value is the regular
     expression ‘(?a:[_a-z][_a-z0-9]*)’.  If this is given and
     'braceidpattern' is ‘None’ this pattern will also apply to braced
     placeholders.

          Note: Since default 'flags' is ‘re.IGNORECASE’, pattern
          ‘[a-z]’ can match with some non-ASCII characters.  That’s why
          we use the local ‘a’ flag here.

     Changed in version 3.7: 'braceidpattern' can be used to define
     separate patterns used inside and outside the braces.

   * 'braceidpattern' – This is like 'idpattern' but describes the
     pattern for braced placeholders.  Defaults to ‘None’ which means to
     fall back to 'idpattern' (i.e.  the same pattern is used both
     inside and outside braces).  If given, this allows you to define
     different patterns for braced and unbraced placeholders.

     Added in version 3.7.

   * 'flags' – The regular expression flags that will be applied when
     compiling the regular expression used for recognizing
     substitutions.  The default value is ‘re.IGNORECASE’.  Note that
     ‘re.VERBOSE’ will always be added to the flags, so custom
     'idpattern's must follow conventions for verbose regular
     expressions.

     Added in version 3.2.

Alternatively, you can provide the entire regular expression pattern by
overriding the class attribute 'pattern'.  If you do this, the value
must be a regular expression object with four named capturing groups.
The capturing groups correspond to the rules given above, along with the
invalid placeholder rule:

   * 'escaped' – This group matches the escape sequence, e.g.  ‘$$’, in
     the default pattern.

   * 'named' – This group matches the unbraced placeholder name; it
     should not include the delimiter in capturing group.

   * 'braced' – This group matches the brace enclosed placeholder name;
     it should not include either the delimiter or braces in the
     capturing group.

   * 'invalid' – This group matches any other delimiter pattern (usually
     a single delimiter), and it should appear last in the regular
     expression.

The methods on this class will raise *note ValueError: 202. if the
pattern matches the template without one of these named groups matching.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0292/

   (2) https://flufli18n.readthedocs.io/en/latest/


File: python.info,  Node: Helper functions,  Prev: Template strings,  Up: string — Common string operations

5.6.1.7 Helper functions
........................

 -- Function: string.capwords (s, sep=None)

     Split the argument into words using *note str.split(): ede,
     capitalize each word using *note str.capitalize(): 2378, and join
     the capitalized words using *note str.join(): 2363.  If the
     optional second argument 'sep' is absent or ‘None’, runs of
     whitespace characters are replaced by a single space and leading
     and trailing whitespace are removed, otherwise 'sep' is used to
     split and join the words.


File: python.info,  Node: re — Regular expression operations,  Next: difflib — Helpers for computing deltas,  Prev: string — Common string operations,  Up: Text Processing Services

5.6.2 ‘re’ — Regular expression operations
------------------------------------------

'Source code:' Lib/re/(1)

__________________________________________________________________

This module provides regular expression matching operations similar to
those found in Perl.

Both patterns and strings to be searched can be Unicode strings (*note
str: 44f.) as well as 8-bit strings (*note bytes: 1c2.).  However,
Unicode strings and 8-bit strings cannot be mixed: that is, you cannot
match a Unicode string with a bytes pattern or vice-versa; similarly,
when asking for a substitution, the replacement string must be of the
same type as both the pattern and the search string.

Regular expressions use the backslash character (‘'\'’) to indicate
special forms or to allow special characters to be used without invoking
their special meaning.  This collides with Python’s usage of the same
character for the same purpose in string literals; for example, to match
a literal backslash, one might have to write ‘'\\\\'’ as the pattern
string, because the regular expression must be ‘\\’, and each backslash
must be expressed as ‘\\’ inside a regular Python string literal.  Also,
please note that any invalid escape sequences in Python’s usage of the
backslash in string literals now generate a *note SyntaxWarning: 469.
and in the future this will become a *note SyntaxError: 18d.  This
behaviour will happen even if it is a valid escape sequence for a
regular expression.

The solution is to use Python’s raw string notation for regular
expression patterns; backslashes are not handled in any special way in a
string literal prefixed with ‘'r'’.  So ‘r"\n"’ is a two-character
string containing ‘'\'’ and ‘'n'’, while ‘"\n"’ is a one-character
string containing a newline.  Usually patterns will be expressed in
Python code using this raw string notation.

It is important to note that most regular expression operations are
available as module-level functions and methods on *note compiled
regular expressions: fc0.  The functions are shortcuts that don’t
require you to compile a regex object first, but miss some fine-tuning
parameters.

See also
........

The third-party regex(2) module, which has an API compatible with the
standard library ‘re’ module, but offers additional functionality and a
more thorough Unicode support.

* Menu:

* Regular Expression Syntax::
* Module Contents::
* Regular Expression Objects::
* Match Objects::
* Regular Expression Examples::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/re/

   (2) https://pypi.org/project/regex/


File: python.info,  Node: Regular Expression Syntax,  Next: Module Contents,  Up: re — Regular expression operations

5.6.2.1 Regular Expression Syntax
.................................

A regular expression (or RE) specifies a set of strings that matches it;
the functions in this module let you check if a particular string
matches a given regular expression (or if a given regular expression
matches a particular string, which comes down to the same thing).

Regular expressions can be concatenated to form new regular expressions;
if 'A' and 'B' are both regular expressions, then 'AB' is also a regular
expression.  In general, if a string 'p' matches 'A' and another string
'q' matches 'B', the string 'pq' will match AB. This holds unless 'A' or
'B' contain low precedence operations; boundary conditions between 'A'
and 'B'; or have numbered group references.  Thus, complex expressions
can easily be constructed from simpler primitive expressions like the
ones described here.  For details of the theory and implementation of
regular expressions, consult the Friedl book *note [Frie09]: 24a6, or
almost any textbook about compiler construction.

A brief explanation of the format of regular expressions follows.  For
further information and a gentler presentation, consult the *note
Regular expression HOWTO: 24a7.

Regular expressions can contain both special and ordinary characters.
Most ordinary characters, like ‘'A'’, ‘'a'’, or ‘'0'’, are the simplest
regular expressions; they simply match themselves.  You can concatenate
ordinary characters, so ‘last’ matches the string ‘'last'’.  (In the
rest of this section, we’ll write RE’s in ‘this special style’, usually
without quotes, and strings to be matched ‘'in single quotes'’.)

Some characters, like ‘'|'’ or ‘'('’, are special.  Special characters
either stand for classes of ordinary characters, or affect how the
regular expressions around them are interpreted.

Repetition operators or quantifiers (‘*’, ‘+’, ‘?’, ‘{m,n}’, etc) cannot
be directly nested.  This avoids ambiguity with the non-greedy modifier
suffix ‘?’, and with other modifiers in other implementations.  To apply
a second repetition to an inner repetition, parentheses may be used.
For example, the expression ‘(?:a{6})*’ matches any multiple of six
‘'a'’ characters.

The special characters are:

‘.’

     (Dot.)  In the default mode, this matches any character except a
     newline.  If the *note DOTALL: 24a8. flag has been specified, this
     matches any character including a newline.  ‘(?s:.)’ matches any
     character regardless of flags.

‘^’

     (Caret.)  Matches the start of the string, and in *note MULTILINE:
     24a9. mode also matches immediately after each newline.

‘$’

     Matches the end of the string or just before the newline at the end
     of the string, and in *note MULTILINE: 24a9. mode also matches
     before a newline.  ‘foo’ matches both ‘foo’ and ‘foobar’, while the
     regular expression ‘foo$’ matches only ‘foo’.  More interestingly,
     searching for ‘foo.$’ in ‘'foo1\nfoo2\n'’ matches ‘foo2’ normally,
     but ‘foo1’ in ‘MULTILINE’ mode; searching for a single ‘$’ in
     ‘'foo\n'’ will find two (empty) matches: one just before the
     newline, and one at the end of the string.

‘*’

     Causes the resulting RE to match 0 or more repetitions of the
     preceding RE, as many repetitions as are possible.  ‘ab*’ will
     match ‘a’, ‘ab’, or ‘a’ followed by any number of ‘b’s.

‘+’

     Causes the resulting RE to match 1 or more repetitions of the
     preceding RE. ‘ab+’ will match ‘a’ followed by any non-zero number
     of ‘b’s; it will not match just ‘a’.

‘?’

     Causes the resulting RE to match 0 or 1 repetitions of the
     preceding RE. ‘ab?’ will match either ‘a’ or ‘ab’.

‘*?’, ‘+?’, ‘??’

     The ‘'*'’, ‘'+'’, and ‘'?'’ quantifiers are all 'greedy'; they
     match as much text as possible.  Sometimes this behaviour isn’t
     desired; if the RE ‘<.*>’ is matched against ‘'<a> b <c>'’, it will
     match the entire string, and not just ‘'<a>'’.  Adding ‘?’ after
     the quantifier makes it perform the match in 'non-greedy' or
     'minimal' fashion; as 'few' characters as possible will be matched.
     Using the RE ‘<.*?>’ will match only ‘'<a>'’.

‘*+’, ‘++’, ‘?+’

     Like the ‘'*'’, ‘'+'’, and ‘'?'’ quantifiers, those where ‘'+'’ is
     appended also match as many times as possible.  However, unlike the
     true greedy quantifiers, these do not allow back-tracking when the
     expression following it fails to match.  These are known as
     'possessive' quantifiers.  For example, ‘a*a’ will match ‘'aaaa'’
     because the ‘a*’ will match all 4 ‘'a'’s, but, when the final ‘'a'’
     is encountered, the expression is backtracked so that in the end
     the ‘a*’ ends up matching 3 ‘'a'’s total, and the fourth ‘'a'’ is
     matched by the final ‘'a'’.  However, when ‘a*+a’ is used to match
     ‘'aaaa'’, the ‘a*+’ will match all 4 ‘'a'’, but when the final
     ‘'a'’ fails to find any more characters to match, the expression
     cannot be backtracked and will thus fail to match.  ‘x*+’, ‘x++’
     and ‘x?+’ are equivalent to ‘(?>x*)’, ‘(?>x+)’ and ‘(?>x?)’
     correspondingly.

     Added in version 3.11.

‘{m}’

     Specifies that exactly 'm' copies of the previous RE should be
     matched; fewer matches cause the entire RE not to match.  For
     example, ‘a{6}’ will match exactly six ‘'a'’ characters, but not
     five.

‘{m,n}’

     Causes the resulting RE to match from 'm' to 'n' repetitions of the
     preceding RE, attempting to match as many repetitions as possible.
     For example, ‘a{3,5}’ will match from 3 to 5 ‘'a'’ characters.
     Omitting 'm' specifies a lower bound of zero, and omitting 'n'
     specifies an infinite upper bound.  As an example, ‘a{4,}b’ will
     match ‘'aaaab'’ or a thousand ‘'a'’ characters followed by a ‘'b'’,
     but not ‘'aaab'’.  The comma may not be omitted or the modifier
     would be confused with the previously described form.

‘{m,n}?’

     Causes the resulting RE to match from 'm' to 'n' repetitions of the
     preceding RE, attempting to match as 'few' repetitions as possible.
     This is the non-greedy version of the previous quantifier.  For
     example, on the 6-character string ‘'aaaaaa'’, ‘a{3,5}’ will match
     5 ‘'a'’ characters, while ‘a{3,5}?’ will only match 3 characters.

‘{m,n}+’

     Causes the resulting RE to match from 'm' to 'n' repetitions of the
     preceding RE, attempting to match as many repetitions as possible
     'without' establishing any backtracking points.  This is the
     possessive version of the quantifier above.  For example, on the
     6-character string ‘'aaaaaa'’, ‘a{3,5}+aa’ attempt to match 5 ‘'a'’
     characters, then, requiring 2 more ‘'a'’s, will need more
     characters than available and thus fail, while ‘a{3,5}aa’ will
     match with ‘a{3,5}’ capturing 5, then 4 ‘'a'’s by backtracking and
     then the final 2 ‘'a'’s are matched by the final ‘aa’ in the
     pattern.  ‘x{m,n}+’ is equivalent to ‘(?>x{m,n})’.

     Added in version 3.11.

‘\’

     Either escapes special characters (permitting you to match
     characters like ‘'*'’, ‘'?'’, and so forth), or signals a special
     sequence; special sequences are discussed below.

     If you’re not using a raw string to express the pattern, remember
     that Python also uses the backslash as an escape sequence in string
     literals; if the escape sequence isn’t recognized by Python’s
     parser, the backslash and subsequent character are included in the
     resulting string.  However, if Python would recognize the resulting
     sequence, the backslash should be repeated twice.  This is
     complicated and hard to understand, so it’s highly recommended that
     you use raw strings for all but the simplest expressions.

‘[]’

     Used to indicate a set of characters.  In a set:

        * Characters can be listed individually, e.g.  ‘[amk]’ will
          match ‘'a'’, ‘'m'’, or ‘'k'’.

        * Ranges of characters can be indicated by giving two characters
          and separating them by a ‘'-'’, for example ‘[a-z]’ will match
          any lowercase ASCII letter, ‘[0-5][0-9]’ will match all the
          two-digits numbers from ‘00’ to ‘59’, and ‘[0-9A-Fa-f]’ will
          match any hexadecimal digit.  If ‘-’ is escaped (e.g.
          ‘[a\-z]’) or if it’s placed as the first or last character
          (e.g.  ‘[-a]’ or ‘[a-]’), it will match a literal ‘'-'’.

        * Special characters except backslash lose their special meaning
          inside sets.  For example, ‘[(+*)]’ will match any of the
          literal characters ‘'('’, ‘'+'’, ‘'*'’, or ‘')'’.

        * Backslash either escapes characters which have special meaning
          in a set such as ‘'-'’, ‘']'’, ‘'^'’ and ‘'\\'’ itself or
          signals a special sequence which represents a single character
          such as ‘\xa0’ or ‘\n’ or a character class such as ‘\w’ or
          ‘\S’ (defined below).  Note that ‘\b’ represents a single
          “backspace” character, not a word boundary as outside a set,
          and numeric escapes such as ‘\1’ are always octal escapes, not
          group references.  Special sequences which do not match a
          single character such as ‘\A’ and ‘\Z’ are not allowed.

        * Characters that are not within a range can be matched by
          'complementing' the set.  If the first character of the set is
          ‘'^'’, all the characters that are 'not' in the set will be
          matched.  For example, ‘[^5]’ will match any character except
          ‘'5'’, and ‘[^^]’ will match any character except ‘'^'’.  ‘^’
          has no special meaning if it’s not the first character in the
          set.

        * To match a literal ‘']'’ inside a set, precede it with a
          backslash, or place it at the beginning of the set.  For
          example, both ‘[()[\]{}]’ and ‘[]()[{}]’ will match a right
          bracket, as well as left bracket, braces, and parentheses.

        * Support of nested sets and set operations as in Unicode
          Technical Standard #18(1) might be added in the future.  This
          would change the syntax, so to facilitate this change a *note
          FutureWarning: 418. will be raised in ambiguous cases for the
          time being.  That includes sets starting with a literal ‘'['’
          or containing literal character sequences ‘'--'’, ‘'&&'’,
          ‘'~~'’, and ‘'||'’.  To avoid a warning escape them with a
          backslash.

     Changed in version 3.7: *note FutureWarning: 418. is raised if a
     character set contains constructs that will change semantically in
     the future.

‘|’

     ‘A|B’, where 'A' and 'B' can be arbitrary REs, creates a regular
     expression that will match either 'A' or 'B'. An arbitrary number
     of REs can be separated by the ‘'|'’ in this way.  This can be used
     inside groups (see below) as well.  As the target string is
     scanned, REs separated by ‘'|'’ are tried from left to right.  When
     one pattern completely matches, that branch is accepted.  This
     means that once 'A' matches, 'B' will not be tested further, even
     if it would produce a longer overall match.  In other words, the
     ‘'|'’ operator is never greedy.  To match a literal ‘'|'’, use
     ‘\|’, or enclose it inside a character class, as in ‘[|]’.

‘(...)’

     Matches whatever regular expression is inside the parentheses, and
     indicates the start and end of a group; the contents of a group can
     be retrieved after a match has been performed, and can be matched
     later in the string with the ‘\number’ special sequence, described
     below.  To match the literals ‘'('’ or ‘')'’, use ‘\(’ or ‘\)’, or
     enclose them inside a character class: ‘[(]’, ‘[)]’.

‘(?...)’

     This is an extension notation (a ‘'?'’ following a ‘'('’ is not
     meaningful otherwise).  The first character after the ‘'?'’
     determines what the meaning and further syntax of the construct is.
     Extensions usually do not create a new group; ‘(?P<name>...)’ is
     the only exception to this rule.  Following are the currently
     supported extensions.

‘(?aiLmsux)’

     (One or more letters from the set ‘'a'’, ‘'i'’, ‘'L'’, ‘'m'’,
     ‘'s'’, ‘'u'’, ‘'x'’.)  The group matches the empty string; the
     letters set the corresponding flags for the entire regular
     expression:

        * *note re.A: 24aa. (ASCII-only matching)

        * *note re.I: 24ab. (ignore case)

        * *note re.L: 24ac. (locale dependent)

        * *note re.M: 24ad. (multi-line)

        * *note re.S: 24ae. (dot matches all)

        * *note re.U: 24af. (Unicode matching)

        * *note re.X: 24b0. (verbose)

     (The flags are described in *note Module Contents: 24b1.)  This is
     useful if you wish to include the flags as part of the regular
     expression, instead of passing a 'flag' argument to the *note
     re.compile(): bf4. function.  Flags should be used first in the
     expression string.

     Changed in version 3.11: This construction can only be used at the
     start of the expression.

‘(?:...)’

     A non-capturing version of regular parentheses.  Matches whatever
     regular expression is inside the parentheses, but the substring
     matched by the group 'cannot' be retrieved after performing a match
     or referenced later in the pattern.

‘(?aiLmsux-imsx:...)’

     (Zero or more letters from the set ‘'a'’, ‘'i'’, ‘'L'’, ‘'m'’,
     ‘'s'’, ‘'u'’, ‘'x'’, optionally followed by ‘'-'’ followed by one
     or more letters from the ‘'i'’, ‘'m'’, ‘'s'’, ‘'x'’.)  The letters
     set or remove the corresponding flags for the part of the
     expression:

        * *note re.A: 24aa. (ASCII-only matching)

        * *note re.I: 24ab. (ignore case)

        * *note re.L: 24ac. (locale dependent)

        * *note re.M: 24ad. (multi-line)

        * *note re.S: 24ae. (dot matches all)

        * *note re.U: 24af. (Unicode matching)

        * *note re.X: 24b0. (verbose)

     (The flags are described in *note Module Contents: 24b1.)

     The letters ‘'a'’, ‘'L'’ and ‘'u'’ are mutually exclusive when used
     as inline flags, so they can’t be combined or follow ‘'-'’.
     Instead, when one of them appears in an inline group, it overrides
     the matching mode in the enclosing group.  In Unicode patterns
     ‘(?a:...)’ switches to ASCII-only matching, and ‘(?u:...)’ switches
     to Unicode matching (default).  In bytes patterns ‘(?L:...)’
     switches to locale dependent matching, and ‘(?a:...)’ switches to
     ASCII-only matching (default).  This override is only in effect for
     the narrow inline group, and the original matching mode is restored
     outside of the group.

     Added in version 3.6.

     Changed in version 3.7: The letters ‘'a'’, ‘'L'’ and ‘'u'’ also can
     be used in a group.

‘(?>...)’

     Attempts to match ‘...’ as if it was a separate regular expression,
     and if successful, continues to match the rest of the pattern
     following it.  If the subsequent pattern fails to match, the stack
     can only be unwound to a point 'before' the ‘(?>...)’ because once
     exited, the expression, known as an 'atomic group', has thrown away
     all stack points within itself.  Thus, ‘(?>.*).’ would never match
     anything because first the ‘.*’ would match all characters
     possible, then, having nothing left to match, the final ‘.’ would
     fail to match.  Since there are no stack points saved in the Atomic
     Group, and there is no stack point before it, the entire expression
     would thus fail to match.

     Added in version 3.11.

‘(?P<name>...)’

     Similar to regular parentheses, but the substring matched by the
     group is accessible via the symbolic group name 'name'.  Group
     names must be valid Python identifiers, and in *note bytes: 1c2.
     patterns they can only contain bytes in the ASCII range.  Each
     group name must be defined only once within a regular expression.
     A symbolic group is also a numbered group, just as if the group
     were not named.

     Named groups can be referenced in three contexts.  If the pattern
     is ‘(?P<quote>['"]).*?(?P=quote)’ (i.e.  matching a string quoted
     with either single or double quotes):

     Context of reference to group “quote”       Ways to reference it
                                                 
     -----------------------------------------------------------------------------------
                                                 
     in the same pattern itself                     * ‘(?P=quote)’ (as shown)
                                                 
                                                    * ‘\1’
                                                 
                                                 
     when processing match object 'm'               * ‘m.group('quote')’
                                                 
                                                    * ‘m.end('quote')’ (etc.)
                                                 
                                                 
     in a string passed to the 'repl' argument      * ‘\g<quote>’
     of ‘re.sub()’                               
                                                    * ‘\g<1>’
                                                 
                                                    * ‘\1’
                                                 

     Changed in version 3.12: In *note bytes: 1c2. patterns, group
     'name' can only contain bytes in the ASCII range
     (‘b'\x00'’-‘b'\x7f'’).

‘(?P=name)’

     A backreference to a named group; it matches whatever text was
     matched by the earlier group named 'name'.

‘(?#...)’

     A comment; the contents of the parentheses are simply ignored.

‘(?=...)’

     Matches if ‘...’ matches next, but doesn’t consume any of the
     string.  This is called a 'lookahead assertion'.  For example,
     ‘Isaac (?=Asimov)’ will match ‘'Isaac '’ only if it’s followed by
     ‘'Asimov'’.

‘(?!...)’

     Matches if ‘...’ doesn’t match next.  This is a 'negative lookahead
     assertion'.  For example, ‘Isaac (?!Asimov)’ will match ‘'Isaac '’
     only if it’s 'not' followed by ‘'Asimov'’.

‘(?<=...)’

     Matches if the current position in the string is preceded by a
     match for ‘...’ that ends at the current position.  This is called
     a 'positive lookbehind assertion'.  ‘(?<=abc)def’ will find a match
     in ‘'abcdef'’, since the lookbehind will back up 3 characters and
     check if the contained pattern matches.  The contained pattern must
     only match strings of some fixed length, meaning that ‘abc’ or
     ‘a|b’ are allowed, but ‘a*’ and ‘a{3,4}’ are not.  Note that
     patterns which start with positive lookbehind assertions will not
     match at the beginning of the string being searched; you will most
     likely want to use the *note search(): 1272. function rather than
     the *note match(): 1273. function:

          >>> import re
          >>> m = re.search('(?<=abc)def', 'abcdef')
          >>> m.group(0)
          'def'

     This example looks for a word following a hyphen:

          >>> m = re.search(r'(?<=-)\w+', 'spam-egg')
          >>> m.group(0)
          'egg'

     Changed in version 3.5: Added support for group references of fixed
     length.

‘(?<!...)’

     Matches if the current position in the string is not preceded by a
     match for ‘...’.  This is called a 'negative lookbehind assertion'.
     Similar to positive lookbehind assertions, the contained pattern
     must only match strings of some fixed length.  Patterns which start
     with negative lookbehind assertions may match at the beginning of
     the string being searched.

‘(?(id/name)yes-pattern|no-pattern)’

     Will try to match with ‘yes-pattern’ if the group with given 'id'
     or 'name' exists, and with ‘no-pattern’ if it doesn’t.
     ‘no-pattern’ is optional and can be omitted.  For example,
     ‘(<)?(\w+@\w+(?:\.\w+)+)(?(1)>|$)’ is a poor email matching
     pattern, which will match with ‘'<user@host.com>'’ as well as
     ‘'user@host.com'’, but not with ‘'<user@host.com'’ nor
     ‘'user@host.com>'’.

     Changed in version 3.12: Group 'id' can only contain ASCII digits.
     In *note bytes: 1c2. patterns, group 'name' can only contain bytes
     in the ASCII range (‘b'\x00'’-‘b'\x7f'’).

The special sequences consist of ‘'\'’ and a character from the list
below.  If the ordinary character is not an ASCII digit or an ASCII
letter, then the resulting RE will match the second character.  For
example, ‘\$’ matches the character ‘'$'’.

‘\number’

     Matches the contents of the group of the same number.  Groups are
     numbered starting from 1.  For example, ‘(.+) \1’ matches ‘'the
     the'’ or ‘'55 55'’, but not ‘'thethe'’ (note the space after the
     group).  This special sequence can only be used to match one of the
     first 99 groups.  If the first digit of 'number' is 0, or 'number'
     is 3 octal digits long, it will not be interpreted as a group
     match, but as the character with octal value 'number'.  Inside the
     ‘'['’ and ‘']'’ of a character class, all numeric escapes are
     treated as characters.

‘\A’

     Matches only at the start of the string.

‘\b’

     Matches the empty string, but only at the beginning or end of a
     word.  A word is defined as a sequence of word characters.  Note
     that formally, ‘\b’ is defined as the boundary between a ‘\w’ and a
     ‘\W’ character (or vice versa), or between ‘\w’ and the beginning
     or end of the string.  This means that ‘r'\bat\b'’ matches ‘'at'’,
     ‘'at.'’, ‘'(at)'’, and ‘'as at ay'’ but not ‘'attempt'’ or
     ‘'atlas'’.

     The default word characters in Unicode (str) patterns are Unicode
     alphanumerics and the underscore, but this can be changed by using
     the *note ASCII: 62f. flag.  Word boundaries are determined by the
     current locale if the *note LOCALE: b88. flag is used.

          Note: Inside a character range, ‘\b’ represents the backspace
          character, for compatibility with Python’s string literals.

‘\B’

     Matches the empty string, but only when it is 'not' at the
     beginning or end of a word.  This means that ‘r'at\B'’ matches
     ‘'athens'’, ‘'atom'’, ‘'attorney'’, but not ‘'at'’, ‘'at.'’, or
     ‘'at!'’.  ‘\B’ is the opposite of ‘\b’, so word characters in
     Unicode (str) patterns are Unicode alphanumerics or the underscore,
     although this can be changed by using the *note ASCII: 62f. flag.
     Word boundaries are determined by the current locale if the *note
     LOCALE: b88. flag is used.

          Note: Note that ‘\B’ does not match an empty string, which
          differs from RE implementations in other programming languages
          such as Perl.  This behavior is kept for compatibility
          reasons.

‘\d’

     For Unicode (str) patterns:

          Matches any Unicode decimal digit (that is, any character in
          Unicode character category [Nd](2)).  This includes ‘[0-9]’,
          and also many other digit characters.

          Matches ‘[0-9]’ if the *note ASCII: 62f. flag is used.

     For 8-bit (bytes) patterns:

          Matches any decimal digit in the ASCII character set; this is
          equivalent to ‘[0-9]’.

‘\D’

     Matches any character which is not a decimal digit.  This is the
     opposite of ‘\d’.

     Matches ‘[^0-9]’ if the *note ASCII: 62f. flag is used.

‘\s’

     For Unicode (str) patterns:

          Matches Unicode whitespace characters (as defined by *note
          str.isspace(): 2382.).  This includes ‘[ \t\n\r\f\v]’, and
          also many other characters, for example the non-breaking
          spaces mandated by typography rules in many languages.

          Matches ‘[ \t\n\r\f\v]’ if the *note ASCII: 62f. flag is used.

     For 8-bit (bytes) patterns:

          Matches characters considered whitespace in the ASCII
          character set; this is equivalent to ‘[ \t\n\r\f\v]’.

‘\S’

     Matches any character which is not a whitespace character.  This is
     the opposite of ‘\s’.

     Matches ‘[^ \t\n\r\f\v]’ if the *note ASCII: 62f. flag is used.

‘\w’

     For Unicode (str) patterns:

          Matches Unicode word characters; this includes all Unicode
          alphanumeric characters (as defined by *note str.isalnum():
          237a.), as well as the underscore (‘_’).

          Matches ‘[a-zA-Z0-9_]’ if the *note ASCII: 62f. flag is used.

     For 8-bit (bytes) patterns:

          Matches characters considered alphanumeric in the ASCII
          character set; this is equivalent to ‘[a-zA-Z0-9_]’.  If the
          *note LOCALE: b88. flag is used, matches characters considered
          alphanumeric in the current locale and the underscore.

‘\W’

     Matches any character which is not a word character.  This is the
     opposite of ‘\w’.  By default, matches non-underscore (‘_’)
     characters for which *note str.isalnum(): 237a. returns ‘False’.

     Matches ‘[^a-zA-Z0-9_]’ if the *note ASCII: 62f. flag is used.

     If the *note LOCALE: b88. flag is used, matches characters which
     are neither alphanumeric in the current locale nor the underscore.

‘\Z’

     Matches only at the end of the string.

Most of the *note escape sequences: 45d. supported by Python string
literals are also accepted by the regular expression parser:

     \a      \b      \f      \n
     \N      \r      \t      \u
     \U      \v      \x      \\

(Note that ‘\b’ is used to represent word boundaries, and means
“backspace” only inside character classes.)

‘'\u'’, ‘'\U'’, and ‘'\N'’ escape sequences are only recognized in
Unicode (str) patterns.  In bytes patterns they are errors.  Unknown
escapes of ASCII letters are reserved for future use and treated as
errors.

Octal escapes are included in a limited form.  If the first digit is a
0, or if there are three octal digits, it is considered an octal escape.
Otherwise, it is a group reference.  As for string literals, octal
escapes are always at most three digits in length.

Changed in version 3.3: The ‘'\u'’ and ‘'\U'’ escape sequences have been
added.

Changed in version 3.6: Unknown escapes consisting of ‘'\'’ and an ASCII
letter now are errors.

Changed in version 3.8: The ‘'\N{NAME}'’ escape sequence has been added.
As in string literals, it expands to the named Unicode character (e.g.
‘'\N{EM DASH}'’).

   ---------- Footnotes ----------

   (1) https://unicode.org/reports/tr18/

   (2) https://www.unicode.org/versions/Unicode15.0.0/ch04.pdf#G134153


File: python.info,  Node: Module Contents,  Next: Regular Expression Objects,  Prev: Regular Expression Syntax,  Up: re — Regular expression operations

5.6.2.2 Module Contents
.......................

The module defines several functions, constants, and an exception.  Some
of the functions are simplified versions of the full featured methods
for compiled regular expressions.  Most non-trivial applications always
use the compiled form.

* Menu:

* Flags::
* Functions: Functions<2>.
* Exceptions: Exceptions<3>.


File: python.info,  Node: Flags,  Next: Functions<2>,  Up: Module Contents

5.6.2.3 Flags
.............

Changed in version 3.6: Flag constants are now instances of *note
RegexFlag: 630, which is a subclass of *note enum.IntFlag: cc1.

 -- Class: re.RegexFlag

     An *note enum.IntFlag: cc1. class containing the regex options
     listed below.

     Added in version 3.11: - added to ‘__all__’

 -- Data: re.A
 -- Data: re.ASCII

     Make ‘\w’, ‘\W’, ‘\b’, ‘\B’, ‘\d’, ‘\D’, ‘\s’ and ‘\S’ perform
     ASCII-only matching instead of full Unicode matching.  This is only
     meaningful for Unicode (str) patterns, and is ignored for bytes
     patterns.

     Corresponds to the inline flag ‘(?a)’.

          Note: The *note U: 24af. flag still exists for backward
          compatibility, but is redundant in Python 3 since matches are
          Unicode by default for ‘str’ patterns, and Unicode matching
          isn’t allowed for bytes patterns.  *note UNICODE: b89. and the
          inline flag ‘(?u)’ are similarly redundant.

 -- Data: re.DEBUG

     Display debug information about compiled expression.

     No corresponding inline flag.

 -- Data: re.I
 -- Data: re.IGNORECASE

     Perform case-insensitive matching; expressions like ‘[A-Z]’ will
     also match lowercase letters.  Full Unicode matching (such as ‘Ü’
     matching ‘ü’) also works unless the *note ASCII: 62f. flag is used
     to disable non-ASCII matches.  The current locale does not change
     the effect of this flag unless the *note LOCALE: b88. flag is also
     used.

     Corresponds to the inline flag ‘(?i)’.

     Note that when the Unicode patterns ‘[a-z]’ or ‘[A-Z]’ are used in
     combination with the *note IGNORECASE: 1837. flag, they will match
     the 52 ASCII letters and 4 additional non-ASCII letters: ‘İ’
     (U+0130, Latin capital letter I with dot above), ‘ı’ (U+0131, Latin
     small letter dotless i), ‘ſ’ (U+017F, Latin small letter long s)
     and ‘K’ (U+212A, Kelvin sign).  If the *note ASCII: 62f. flag is
     used, only letters ‘a’ to ‘z’ and ‘A’ to ‘Z’ are matched.

 -- Data: re.L
 -- Data: re.LOCALE

     Make ‘\w’, ‘\W’, ‘\b’, ‘\B’ and case-insensitive matching dependent
     on the current locale.  This flag can be used only with bytes
     patterns.

     Corresponds to the inline flag ‘(?L)’.

          Warning: This flag is discouraged; consider Unicode matching
          instead.  The locale mechanism is very unreliable as it only
          handles one “culture” at a time and only works with 8-bit
          locales.  Unicode matching is enabled by default for Unicode
          (str) patterns and it is able to handle different locales and
          languages.

     Changed in version 3.6: *note LOCALE: b88. can be used only with
     bytes patterns and is not compatible with *note ASCII: 62f.

     Changed in version 3.7: Compiled regular expression objects with
     the *note LOCALE: b88. flag no longer depend on the locale at
     compile time.  Only the locale at matching time affects the result
     of matching.

 -- Data: re.M
 -- Data: re.MULTILINE

     When specified, the pattern character ‘'^'’ matches at the
     beginning of the string and at the beginning of each line
     (immediately following each newline); and the pattern character
     ‘'$'’ matches at the end of the string and at the end of each line
     (immediately preceding each newline).  By default, ‘'^'’ matches
     only at the beginning of the string, and ‘'$'’ only at the end of
     the string and immediately before the newline (if any) at the end
     of the string.

     Corresponds to the inline flag ‘(?m)’.

 -- Data: re.NOFLAG

     Indicates no flag being applied, the value is ‘0’.  This flag may
     be used as a default value for a function keyword argument or as a
     base value that will be conditionally ORed with other flags.
     Example of use as a default value:

          def myfunc(text, flag=re.NOFLAG):
              return re.match(text, flag)

     Added in version 3.11.

 -- Data: re.S
 -- Data: re.DOTALL

     Make the ‘'.'’ special character match any character at all,
     including a newline; without this flag, ‘'.'’ will match anything
     'except' a newline.

     Corresponds to the inline flag ‘(?s)’.

 -- Data: re.U
 -- Data: re.UNICODE

     In Python 3, Unicode characters are matched by default for ‘str’
     patterns.  This flag is therefore redundant with 'no effect' and is
     only kept for backward compatibility.

     See *note ASCII: 62f. to restrict matching to ASCII characters
     instead.

 -- Data: re.X
 -- Data: re.VERBOSE

     This flag allows you to write regular expressions that look nicer
     and are more readable by allowing you to visually separate logical
     sections of the pattern and add comments.  Whitespace within the
     pattern is ignored, except when in a character class, or when
     preceded by an unescaped backslash, or within tokens like ‘*?’,
     ‘(?:’ or ‘(?P<...>’.  For example, ‘(? :’ and ‘* ?’ are not
     allowed.  When a line contains a ‘#’ that is not in a character
     class and is not preceded by an unescaped backslash, all characters
     from the leftmost such ‘#’ through the end of the line are ignored.

     This means that the two following regular expression objects that
     match a decimal number are functionally equal:

          a = re.compile(r"""\d +  # the integral part
                             \.    # the decimal point
                             \d *  # some fractional digits""", re.X)
          b = re.compile(r"\d+\.\d*")

     Corresponds to the inline flag ‘(?x)’.


File: python.info,  Node: Functions<2>,  Next: Exceptions<3>,  Prev: Flags,  Up: Module Contents

5.6.2.4 Functions
.................

 -- Function: re.compile (pattern, flags=0)

     Compile a regular expression pattern into a *note regular
     expression object: fc0, which can be used for matching using its
     *note match(): 24b9, *note search(): 24ba. and other methods,
     described below.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     The sequence

          prog = re.compile(pattern)
          result = prog.match(string)

     is equivalent to

          result = re.match(pattern, string)

     but using *note re.compile(): bf4. and saving the resulting regular
     expression object for reuse is more efficient when the expression
     will be used several times in a single program.

          Note: The compiled versions of the most recent patterns passed
          to *note re.compile(): bf4. and the module-level matching
          functions are cached, so programs that use only a few regular
          expressions at a time needn’t worry about compiling regular
          expressions.

 -- Function: re.search (pattern, string, flags=0)

     Scan through 'string' looking for the first location where the
     regular expression 'pattern' produces a match, and return a
     corresponding *note Match: cee.  Return ‘None’ if no position in
     the string matches the pattern; note that this is different from
     finding a zero-length match at some point in the string.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

 -- Function: re.match (pattern, string, flags=0)

     If zero or more characters at the beginning of 'string' match the
     regular expression 'pattern', return a corresponding *note Match:
     cee.  Return ‘None’ if the string does not match the pattern; note
     that this is different from a zero-length match.

     Note that even in *note MULTILINE: 24a9. mode, *note re.match():
     1273. will only match at the beginning of the string and not at the
     beginning of each line.

     If you want to locate a match anywhere in 'string', use *note
     search(): 1272. instead (see also *note search() vs.  match():
     24bb.).

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

 -- Function: re.fullmatch (pattern, string, flags=0)

     If the whole 'string' matches the regular expression 'pattern',
     return a corresponding *note Match: cee.  Return ‘None’ if the
     string does not match the pattern; note that this is different from
     a zero-length match.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     Added in version 3.4.

 -- Function: re.split (pattern, string, maxsplit=0, flags=0)

     Split 'string' by the occurrences of 'pattern'.  If capturing
     parentheses are used in 'pattern', then the text of all groups in
     the pattern are also returned as part of the resulting list.  If
     'maxsplit' is nonzero, at most 'maxsplit' splits occur, and the
     remainder of the string is returned as the final element of the
     list.

          >>> re.split(r'\W+', 'Words, words, words.')
          ['Words', 'words', 'words', '']
          >>> re.split(r'(\W+)', 'Words, words, words.')
          ['Words', ', ', 'words', ', ', 'words', '.', '']
          >>> re.split(r'\W+', 'Words, words, words.', maxsplit=1)
          ['Words', 'words, words.']
          >>> re.split('[a-f]+', '0a3B9', flags=re.IGNORECASE)
          ['0', '3', '9']

     If there are capturing groups in the separator and it matches at
     the start of the string, the result will start with an empty
     string.  The same holds for the end of the string:

          >>> re.split(r'(\W+)', '...words, words...')
          ['', '...', 'words', ', ', 'words', '...', '']

     That way, separator components are always found at the same
     relative indices within the result list.

     Adjacent empty matches are not possible, but an empty match can
     occur immediately after a non-empty match.

          >>> re.split(r'\b', 'Words, words, words.')
          ['', 'Words', ', ', 'words', ', ', 'words', '.']
          >>> re.split(r'\W*', '...words...')
          ['', '', 'w', 'o', 'r', 'd', 's', '', '']
          >>> re.split(r'(\W*)', '...words...')
          ['', '...', '', '', 'w', '', 'o', '', 'r', '', 'd', '', 's', '...', '', '', '']

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     Changed in version 3.1: Added the optional flags argument.

     Changed in version 3.7: Added support of splitting on a pattern
     that could match an empty string.

     Deprecated since version 3.13: Passing 'maxsplit' and 'flags' as
     positional arguments is deprecated.  In future Python versions they
     will be *note keyword-only parameters: 2a5.

 -- Function: re.findall (pattern, string, flags=0)

     Return all non-overlapping matches of 'pattern' in 'string', as a
     list of strings or tuples.  The 'string' is scanned left-to-right,
     and matches are returned in the order found.  Empty matches are
     included in the result.

     The result depends on the number of capturing groups in the
     pattern.  If there are no groups, return a list of strings matching
     the whole pattern.  If there is exactly one group, return a list of
     strings matching that group.  If multiple groups are present,
     return a list of tuples of strings matching the groups.
     Non-capturing groups do not affect the form of the result.

          >>> re.findall(r'\bf[a-z]*', 'which foot or hand fell fastest')
          ['foot', 'fell', 'fastest']
          >>> re.findall(r'(\w+)=(\d+)', 'set width=20 and height=10')
          [('width', '20'), ('height', '10')]

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     Changed in version 3.7: Non-empty matches can now start just after
     a previous empty match.

 -- Function: re.finditer (pattern, string, flags=0)

     Return an *note iterator: 1ac. yielding *note Match: cee. objects
     over all non-overlapping matches for the RE 'pattern' in 'string'.
     The 'string' is scanned left-to-right, and matches are returned in
     the order found.  Empty matches are included in the result.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     Changed in version 3.7: Non-empty matches can now start just after
     a previous empty match.

 -- Function: re.sub (pattern, repl, string, count=0, flags=0)

     Return the string obtained by replacing the leftmost
     non-overlapping occurrences of 'pattern' in 'string' by the
     replacement 'repl'.  If the pattern isn’t found, 'string' is
     returned unchanged.  'repl' can be a string or a function; if it is
     a string, any backslash escapes in it are processed.  That is, ‘\n’
     is converted to a single newline character, ‘\r’ is converted to a
     carriage return, and so forth.  Unknown escapes of ASCII letters
     are reserved for future use and treated as errors.  Other unknown
     escapes such as ‘\&’ are left alone.  Backreferences, such as ‘\6’,
     are replaced with the substring matched by group 6 in the pattern.
     For example:

          >>> re.sub(r'def\s+([a-zA-Z_][a-zA-Z_0-9]*)\s*\(\s*\):',
          ...        r'static PyObject*\npy_\1(void)\n{',
          ...        'def myfunc():')
          'static PyObject*\npy_myfunc(void)\n{'

     If 'repl' is a function, it is called for every non-overlapping
     occurrence of 'pattern'.  The function takes a single *note Match:
     cee. argument, and returns the replacement string.  For example:

          >>> def dashrepl(matchobj):
          ...     if matchobj.group(0) == '-': return ' '
          ...     else: return '-'
          ...
          >>> re.sub('-{1,2}', dashrepl, 'pro----gram-files')
          'pro--gram files'
          >>> re.sub(r'\sAND\s', ' & ', 'Baked Beans And Spam', flags=re.IGNORECASE)
          'Baked Beans & Spam'

     The pattern may be a string or a *note Pattern: 190d.

     The optional argument 'count' is the maximum number of pattern
     occurrences to be replaced; 'count' must be a non-negative integer.
     If omitted or zero, all occurrences will be replaced.

     Adjacent empty matches are not possible, but an empty match can
     occur immediately after a non-empty match.  As a result, ‘sub('x*',
     '-', 'abxd')’ returns ‘'-a-b--d-'’ instead of ‘'-a-b-d-'’.

     In string-type 'repl' arguments, in addition to the character
     escapes and backreferences described above, ‘\g<name>’ will use the
     substring matched by the group named ‘name’, as defined by the
     ‘(?P<name>...)’ syntax.  ‘\g<number>’ uses the corresponding group
     number; ‘\g<2>’ is therefore equivalent to ‘\2’, but isn’t
     ambiguous in a replacement such as ‘\g<2>0’.  ‘\20’ would be
     interpreted as a reference to group 20, not a reference to group 2
     followed by the literal character ‘'0'’.  The backreference ‘\g<0>’
     substitutes in the entire substring matched by the RE.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

     Changed in version 3.1: Added the optional flags argument.

     Changed in version 3.5: Unmatched groups are replaced with an empty
     string.

     Changed in version 3.6: Unknown escapes in 'pattern' consisting of
     ‘'\'’ and an ASCII letter now are errors.

     Changed in version 3.7: Unknown escapes in 'repl' consisting of
     ‘'\'’ and an ASCII letter now are errors.  An empty match can occur
     immediately after a non-empty match.

     Changed in version 3.12: Group 'id' can only contain ASCII digits.
     In *note bytes: 1c2. replacement strings, group 'name' can only
     contain bytes in the ASCII range (‘b'\x00'’-‘b'\x7f'’).

     Deprecated since version 3.13: Passing 'count' and 'flags' as
     positional arguments is deprecated.  In future Python versions they
     will be *note keyword-only parameters: 2a5.

 -- Function: re.subn (pattern, repl, string, count=0, flags=0)

     Perform the same operation as *note sub(): 2a3, but return a tuple
     ‘(new_string, number_of_subs_made)’.

     The expression’s behaviour can be modified by specifying a 'flags'
     value.  Values can be any of the *note flags: 24b4. variables,
     combined using bitwise OR (the ‘|’ operator).

 -- Function: re.escape (pattern)

     Escape special characters in 'pattern'.  This is useful if you want
     to match an arbitrary literal string that may have regular
     expression metacharacters in it.  For example:

          >>> print(re.escape('https://www.python.org'))
          https://www\.python\.org

          >>> legal_chars = string.ascii_lowercase + string.digits + "!#$%&'*+-.^_`|~:"
          >>> print('[%s]+' % re.escape(legal_chars))
          [abcdefghijklmnopqrstuvwxyz0123456789!\#\$%\&'\*\+\-\.\^_`\|\~:]+

          >>> operators = ['+', '-', '*', '/', '**']
          >>> print('|'.join(map(re.escape, sorted(operators, reverse=True))))
          /|\-|\+|\*\*|\*

     This function must not be used for the replacement string in *note
     sub(): 2a3. and *note subn(): 2a4, only backslashes should be
     escaped.  For example:

          >>> digits_re = r'\d+'
          >>> sample = '/usr/sbin/sendmail - 0 errors, 12 warnings'
          >>> print(re.sub(digits_re, digits_re.replace('\\', r'\\'), sample))
          /usr/sbin/sendmail - \d+ errors, \d+ warnings

     Changed in version 3.3: The ‘'_'’ character is no longer escaped.

     Changed in version 3.7: Only characters that can have special
     meaning in a regular expression are escaped.  As a result, ‘'!'’,
     ‘'"'’, ‘'%'’, ‘"'"’, ‘','’, ‘'/'’, ‘':'’, ‘';'’, ‘'<'’, ‘'='’,
     ‘'>'’, ‘'@'’, and ‘"`"’ are no longer escaped.

 -- Function: re.purge ()

     Clear the regular expression cache.


File: python.info,  Node: Exceptions<3>,  Prev: Functions<2>,  Up: Module Contents

5.6.2.5 Exceptions
..................

 -- Exception: re.PatternError (msg, pattern=None, pos=None)

     Exception raised when a string passed to one of the functions here
     is not a valid regular expression (for example, it might contain
     unmatched parentheses) or when some other error occurs during
     compilation or matching.  It is never an error if a string contains
     no match for a pattern.  The ‘PatternError’ instance has the
     following additional attributes:

      -- Attribute: msg

          The unformatted error message.

      -- Attribute: pattern

          The regular expression pattern.

      -- Attribute: pos

          The index in 'pattern' where compilation failed (may be
          ‘None’).

      -- Attribute: lineno

          The line corresponding to 'pos' (may be ‘None’).

      -- Attribute: colno

          The column corresponding to 'pos' (may be ‘None’).

     Changed in version 3.5: Added additional attributes.

     Changed in version 3.13: ‘PatternError’ was originally named
     ‘error’; the latter is kept as an alias for backward compatibility.


File: python.info,  Node: Regular Expression Objects,  Next: Match Objects,  Prev: Module Contents,  Up: re — Regular expression operations

5.6.2.6 Regular Expression Objects
..................................

 -- Class: re.Pattern

     Compiled regular expression object returned by *note re.compile():
     bf4.

     Changed in version 3.9: *note re.Pattern: 190d. supports ‘[]’ to
     indicate a Unicode (str) or bytes pattern.  See *note Generic Alias
     Type: 6b5.

 -- Method: Pattern.search (string[, pos[, endpos]])

     Scan through 'string' looking for the first location where this
     regular expression produces a match, and return a corresponding
     *note Match: cee.  Return ‘None’ if no position in the string
     matches the pattern; note that this is different from finding a
     zero-length match at some point in the string.

     The optional second parameter 'pos' gives an index in the string
     where the search is to start; it defaults to ‘0’.  This is not
     completely equivalent to slicing the string; the ‘'^'’ pattern
     character matches at the real beginning of the string and at
     positions just after a newline, but not necessarily at the index
     where the search is to start.

     The optional parameter 'endpos' limits how far the string will be
     searched; it will be as if the string is 'endpos' characters long,
     so only the characters from 'pos' to ‘endpos - 1’ will be searched
     for a match.  If 'endpos' is less than 'pos', no match will be
     found; otherwise, if 'rx' is a compiled regular expression object,
     ‘rx.search(string, 0, 50)’ is equivalent to ‘rx.search(string[:50],
     0)’.

          >>> pattern = re.compile("d")
          >>> pattern.search("dog")     # Match at index 0
          <re.Match object; span=(0, 1), match='d'>
          >>> pattern.search("dog", 1)  # No match; search doesn't include the "d"

 -- Method: Pattern.match (string[, pos[, endpos]])

     If zero or more characters at the 'beginning' of 'string' match
     this regular expression, return a corresponding *note Match: cee.
     Return ‘None’ if the string does not match the pattern; note that
     this is different from a zero-length match.

     The optional 'pos' and 'endpos' parameters have the same meaning as
     for the *note search(): 24ba. method.

          >>> pattern = re.compile("o")
          >>> pattern.match("dog")      # No match as "o" is not at the start of "dog".
          >>> pattern.match("dog", 1)   # Match as "o" is the 2nd character of "dog".
          <re.Match object; span=(1, 2), match='o'>

     If you want to locate a match anywhere in 'string', use *note
     search(): 24ba. instead (see also *note search() vs.  match():
     24bb.).

 -- Method: Pattern.fullmatch (string[, pos[, endpos]])

     If the whole 'string' matches this regular expression, return a
     corresponding *note Match: cee.  Return ‘None’ if the string does
     not match the pattern; note that this is different from a
     zero-length match.

     The optional 'pos' and 'endpos' parameters have the same meaning as
     for the *note search(): 24ba. method.

          >>> pattern = re.compile("o[gh]")
          >>> pattern.fullmatch("dog")      # No match as "o" is not at the start of "dog".
          >>> pattern.fullmatch("ogre")     # No match as not the full string matches.
          >>> pattern.fullmatch("doggie", 1, 3)   # Matches within given limits.
          <re.Match object; span=(1, 3), match='og'>

     Added in version 3.4.

 -- Method: Pattern.split (string, maxsplit=0)

     Identical to the *note split(): 2a2. function, using the compiled
     pattern.

 -- Method: Pattern.findall (string[, pos[, endpos]])

     Similar to the *note findall(): 1065. function, using the compiled
     pattern, but also accepts optional 'pos' and 'endpos' parameters
     that limit the search region like for *note search(): 1272.

 -- Method: Pattern.finditer (string[, pos[, endpos]])

     Similar to the *note finditer(): 1549. function, using the compiled
     pattern, but also accepts optional 'pos' and 'endpos' parameters
     that limit the search region like for *note search(): 1272.

 -- Method: Pattern.sub (repl, string, count=0)

     Identical to the *note sub(): 2a3. function, using the compiled
     pattern.

 -- Method: Pattern.subn (repl, string, count=0)

     Identical to the *note subn(): 2a4. function, using the compiled
     pattern.

 -- Attribute: Pattern.flags

     The regex matching flags.  This is a combination of the flags given
     to *note compile(): bf4, any ‘(?...)’ inline flags in the pattern,
     and implicit flags such as *note UNICODE: b89. if the pattern is a
     Unicode string.

 -- Attribute: Pattern.groups

     The number of capturing groups in the pattern.

 -- Attribute: Pattern.groupindex

     A dictionary mapping any symbolic group names defined by ‘(?P<id>)’
     to group numbers.  The dictionary is empty if no symbolic groups
     were used in the pattern.

 -- Attribute: Pattern.pattern

     The pattern string from which the pattern object was compiled.

Changed in version 3.7: Added support of *note copy.copy(): 537. and
*note copy.deepcopy(): b8a.  Compiled regular expression objects are
considered atomic.


File: python.info,  Node: Match Objects,  Next: Regular Expression Examples,  Prev: Regular Expression Objects,  Up: re — Regular expression operations

5.6.2.7 Match Objects
.....................

Match objects always have a boolean value of ‘True’.  Since *note
match(): 24b9. and *note search(): 24ba. return ‘None’ when there is no
match, you can test whether there was a match with a simple ‘if’
statement:

     match = re.search(pattern, string)
     if match:
         process(match)

 -- Class: re.Match

     Match object returned by successful ‘match’es and ‘search’es.

     Changed in version 3.9: *note re.Match: cee. supports ‘[]’ to
     indicate a Unicode (str) or bytes match.  See *note Generic Alias
     Type: 6b5.

 -- Method: Match.expand (template)

     Return the string obtained by doing backslash substitution on the
     template string 'template', as done by the *note sub(): 24c2.
     method.  Escapes such as ‘\n’ are converted to the appropriate
     characters, and numeric backreferences (‘\1’, ‘\2’) and named
     backreferences (‘\g<1>’, ‘\g<name>’) are replaced by the contents
     of the corresponding group.  The backreference ‘\g<0>’ will be
     replaced by the entire match.

     Changed in version 3.5: Unmatched groups are replaced with an empty
     string.

 -- Method: Match.group ([group1, ...])

     Returns one or more subgroups of the match.  If there is a single
     argument, the result is a single string; if there are multiple
     arguments, the result is a tuple with one item per argument.
     Without arguments, 'group1' defaults to zero (the whole match is
     returned).  If a 'groupN' argument is zero, the corresponding
     return value is the entire matching string; if it is a positive
     integer, it is the string matching the corresponding parenthesized
     group.  If a group number is negative or larger than the number of
     groups defined in the pattern, an *note IndexError: 1585. exception
     is raised.  If a group is contained in a part of the pattern that
     did not match, the corresponding result is ‘None’.  If a group is
     contained in a part of the pattern that matched multiple times, the
     last match is returned.

          >>> m = re.match(r"(\w+) (\w+)", "Isaac Newton, physicist")
          >>> m.group(0)       # The entire match
          'Isaac Newton'
          >>> m.group(1)       # The first parenthesized subgroup.
          'Isaac'
          >>> m.group(2)       # The second parenthesized subgroup.
          'Newton'
          >>> m.group(1, 2)    # Multiple arguments give us a tuple.
          ('Isaac', 'Newton')

     If the regular expression uses the ‘(?P<name>...)’ syntax, the
     'groupN' arguments may also be strings identifying groups by their
     group name.  If a string argument is not used as a group name in
     the pattern, an *note IndexError: 1585. exception is raised.

     A moderately complicated example:

          >>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Malcolm Reynolds")
          >>> m.group('first_name')
          'Malcolm'
          >>> m.group('last_name')
          'Reynolds'

     Named groups can also be referred to by their index:

          >>> m.group(1)
          'Malcolm'
          >>> m.group(2)
          'Reynolds'

     If a group matches multiple times, only the last match is
     accessible:

          >>> m = re.match(r"(..)+", "a1b2c3")  # Matches 3 times.
          >>> m.group(1)                        # Returns only the last match.
          'c3'

 -- Method: Match.__getitem__ (g)

     This is identical to ‘m.group(g)’.  This allows easier access to an
     individual group from a match:

          >>> m = re.match(r"(\w+) (\w+)", "Isaac Newton, physicist")
          >>> m[0]       # The entire match
          'Isaac Newton'
          >>> m[1]       # The first parenthesized subgroup.
          'Isaac'
          >>> m[2]       # The second parenthesized subgroup.
          'Newton'

     Named groups are supported as well:

          >>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Isaac Newton")
          >>> m['first_name']
          'Isaac'
          >>> m['last_name']
          'Newton'

     Added in version 3.6.

 -- Method: Match.groups (default=None)

     Return a tuple containing all the subgroups of the match, from 1 up
     to however many groups are in the pattern.  The 'default' argument
     is used for groups that did not participate in the match; it
     defaults to ‘None’.

     For example:

          >>> m = re.match(r"(\d+)\.(\d+)", "24.1632")
          >>> m.groups()
          ('24', '1632')

     If we make the decimal place and everything after it optional, not
     all groups might participate in the match.  These groups will
     default to ‘None’ unless the 'default' argument is given:

          >>> m = re.match(r"(\d+)\.?(\d+)?", "24")
          >>> m.groups()      # Second group defaults to None.
          ('24', None)
          >>> m.groups('0')   # Now, the second group defaults to '0'.
          ('24', '0')

 -- Method: Match.groupdict (default=None)

     Return a dictionary containing all the 'named' subgroups of the
     match, keyed by the subgroup name.  The 'default' argument is used
     for groups that did not participate in the match; it defaults to
     ‘None’.  For example:

          >>> m = re.match(r"(?P<first_name>\w+) (?P<last_name>\w+)", "Malcolm Reynolds")
          >>> m.groupdict()
          {'first_name': 'Malcolm', 'last_name': 'Reynolds'}

 -- Method: Match.start ([group])
 -- Method: Match.end ([group])

     Return the indices of the start and end of the substring matched by
     'group'; 'group' defaults to zero (meaning the whole matched
     substring).  Return ‘-1’ if 'group' exists but did not contribute
     to the match.  For a match object 'm', and a group 'g' that did
     contribute to the match, the substring matched by group 'g'
     (equivalent to ‘m.group(g)’) is

          m.string[m.start(g):m.end(g)]

     Note that ‘m.start(group)’ will equal ‘m.end(group)’ if 'group'
     matched a null string.  For example, after ‘m = re.search('b(c?)',
     'cba')’, ‘m.start(0)’ is 1, ‘m.end(0)’ is 2, ‘m.start(1)’ and
     ‘m.end(1)’ are both 2, and ‘m.start(2)’ raises an *note IndexError:
     1585. exception.

     An example that will remove 'remove_this' from email addresses:

          >>> email = "tony@tiremove_thisger.net"
          >>> m = re.search("remove_this", email)
          >>> email[:m.start()] + email[m.end():]
          'tony@tiger.net'

 -- Method: Match.span ([group])

     For a match 'm', return the 2-tuple ‘(m.start(group),
     m.end(group))’.  Note that if 'group' did not contribute to the
     match, this is ‘(-1, -1)’.  'group' defaults to zero, the entire
     match.

 -- Attribute: Match.pos

     The value of 'pos' which was passed to the *note search(): 24ba. or
     *note match(): 24b9. method of a *note regex object: fc0.  This is
     the index into the string at which the RE engine started looking
     for a match.

 -- Attribute: Match.endpos

     The value of 'endpos' which was passed to the *note search(): 24ba.
     or *note match(): 24b9. method of a *note regex object: fc0.  This
     is the index into the string beyond which the RE engine will not
     go.

 -- Attribute: Match.lastindex

     The integer index of the last matched capturing group, or ‘None’ if
     no group was matched at all.  For example, the expressions ‘(a)b’,
     ‘((a)(b))’, and ‘((ab))’ will have ‘lastindex == 1’ if applied to
     the string ‘'ab'’, while the expression ‘(a)(b)’ will have
     ‘lastindex == 2’, if applied to the same string.

 -- Attribute: Match.lastgroup

     The name of the last matched capturing group, or ‘None’ if the
     group didn’t have a name, or if no group was matched at all.

 -- Attribute: Match.re

     The *note regular expression object: fc0. whose *note match():
     24b9. or *note search(): 24ba. method produced this match instance.

 -- Attribute: Match.string

     The string passed to *note match(): 24b9. or *note search(): 24ba.

Changed in version 3.7: Added support of *note copy.copy(): 537. and
*note copy.deepcopy(): b8a.  Match objects are considered atomic.


File: python.info,  Node: Regular Expression Examples,  Prev: Match Objects,  Up: re — Regular expression operations

5.6.2.8 Regular Expression Examples
...................................

* Menu:

* Checking for a Pair::
* Simulating scanf(): Simulating scanf.
* search() vs. match(): search vs match.
* Making a Phonebook::
* Text Munging::
* Finding all Adverbs::
* Finding all Adverbs and their Positions::
* Raw String Notation::
* Writing a Tokenizer::


File: python.info,  Node: Checking for a Pair,  Next: Simulating scanf,  Up: Regular Expression Examples

5.6.2.9 Checking for a Pair
...........................

In this example, we’ll use the following helper function to display
match objects a little more gracefully:

     def displaymatch(match):
         if match is None:
             return None
         return '<Match: %r, groups=%r>' % (match.group(), match.groups())

Suppose you are writing a poker program where a player’s hand is
represented as a 5-character string with each character representing a
card, “a” for ace, “k” for king, “q” for queen, “j” for jack, “t” for
10, and “2” through “9” representing the card with that value.

To see if a given string is a valid hand, one could do the following:

     >>> valid = re.compile(r"^[a2-9tjqk]{5}$")
     >>> displaymatch(valid.match("akt5q"))  # Valid.
     "<Match: 'akt5q', groups=()>"
     >>> displaymatch(valid.match("akt5e"))  # Invalid.
     >>> displaymatch(valid.match("akt"))    # Invalid.
     >>> displaymatch(valid.match("727ak"))  # Valid.
     "<Match: '727ak', groups=()>"

That last hand, ‘"727ak"’, contained a pair, or two of the same valued
cards.  To match this with a regular expression, one could use
backreferences as such:

     >>> pair = re.compile(r".*(.).*\1")
     >>> displaymatch(pair.match("717ak"))     # Pair of 7s.
     "<Match: '717', groups=('7',)>"
     >>> displaymatch(pair.match("718ak"))     # No pairs.
     >>> displaymatch(pair.match("354aa"))     # Pair of aces.
     "<Match: '354aa', groups=('a',)>"

To find out what card the pair consists of, one could use the *note
group(): 1066. method of the match object in the following manner:

     >>> pair = re.compile(r".*(.).*\1")
     >>> pair.match("717ak").group(1)
     '7'

     # Error because re.match() returns None, which doesn't have a group() method:
     >>> pair.match("718ak").group(1)
     Traceback (most recent call last):
       File "<pyshell#23>", line 1, in <module>
         re.match(r".*(.).*\1", "718ak").group(1)
     AttributeError: 'NoneType' object has no attribute 'group'

     >>> pair.match("354aa").group(1)
     'a'


File: python.info,  Node: Simulating scanf,  Next: search vs match,  Prev: Checking for a Pair,  Up: Regular Expression Examples

5.6.2.10 Simulating scanf()
...........................

Python does not currently have an equivalent to ‘scanf()’.  Regular
expressions are generally more powerful, though also more verbose, than
‘scanf()’ format strings.  The table below offers some more-or-less
equivalent mappings between ‘scanf()’ format tokens and regular
expressions.

‘scanf()’ Token                      Regular Expression
                                     
---------------------------------------------------------------------------------------
                                     
‘%c’                                 ‘.’
                                     
                                     
‘%5c’                                ‘.{5}’
                                     
                                     
‘%d’                                 ‘[-+]?\d+’
                                     
                                     
‘%e’, ‘%E’, ‘%f’, ‘%g’               ‘[-+]?(\d+(\.\d*)?|\.\d+)([eE][-+]?\d+)?’
                                     
                                     
‘%i’                                 ‘[-+]?(0[xX][\dA-Fa-f]+|0[0-7]*|\d+)’
                                     
                                     
‘%o’                                 ‘[-+]?[0-7]+’
                                     
                                     
‘%s’                                 ‘\S+’
                                     
                                     
‘%u’                                 ‘\d+’
                                     
                                     
‘%x’, ‘%X’                           ‘[-+]?(0[xX])?[\dA-Fa-f]+’
                                     

To extract the filename and numbers from a string like

     /usr/sbin/sendmail - 0 errors, 4 warnings

you would use a ‘scanf()’ format like

     %s - %d errors, %d warnings

The equivalent regular expression would be

     (\S+) - (\d+) errors, (\d+) warnings


File: python.info,  Node: search vs match,  Next: Making a Phonebook,  Prev: Simulating scanf,  Up: Regular Expression Examples

5.6.2.11 search() vs. match()
.............................

Python offers different primitive operations based on regular
expressions:

   + *note re.match(): 1273. checks for a match only at the beginning of
     the string

   + *note re.search(): 1272. checks for a match anywhere in the string
     (this is what Perl does by default)

   + *note re.fullmatch(): fbe. checks for entire string to be a match

For example:

     >>> re.match("c", "abcdef")    # No match
     >>> re.search("c", "abcdef")   # Match
     <re.Match object; span=(2, 3), match='c'>
     >>> re.fullmatch("p.*n", "python") # Match
     <re.Match object; span=(0, 6), match='python'>
     >>> re.fullmatch("r.*n", "python") # No match

Regular expressions beginning with ‘'^'’ can be used with *note
search(): 1272. to restrict the match at the beginning of the string:

     >>> re.match("c", "abcdef")    # No match
     >>> re.search("^c", "abcdef")  # No match
     >>> re.search("^a", "abcdef")  # Match
     <re.Match object; span=(0, 1), match='a'>

Note however that in *note MULTILINE: 24a9. mode *note match(): 1273.
only matches at the beginning of the string, whereas using *note
search(): 1272. with a regular expression beginning with ‘'^'’ will
match at the beginning of each line.

     >>> re.match("X", "A\nB\nX", re.MULTILINE)  # No match
     >>> re.search("^X", "A\nB\nX", re.MULTILINE)  # Match
     <re.Match object; span=(4, 5), match='X'>


File: python.info,  Node: Making a Phonebook,  Next: Text Munging,  Prev: search vs match,  Up: Regular Expression Examples

5.6.2.12 Making a Phonebook
...........................

*note split(): 2a2. splits a string into a list delimited by the passed
pattern.  The method is invaluable for converting textual data into data
structures that can be easily read and modified by Python as
demonstrated in the following example that creates a phonebook.

First, here is the input.  Normally it may come from a file, here we are
using triple-quoted string syntax

     >>> text = """Ross McFluff: 834.345.1254 155 Elm Street
     ...
     ... Ronald Heathmore: 892.345.3428 436 Finley Avenue
     ... Frank Burger: 925.541.7625 662 South Dogwood Way
     ...
     ...
     ... Heather Albrecht: 548.326.4584 919 Park Place"""

The entries are separated by one or more newlines.  Now we convert the
string into a list with each nonempty line having its own entry:

     >>> entries = re.split("\n+", text)
     >>> entries
     ['Ross McFluff: 834.345.1254 155 Elm Street',
     'Ronald Heathmore: 892.345.3428 436 Finley Avenue',
     'Frank Burger: 925.541.7625 662 South Dogwood Way',
     'Heather Albrecht: 548.326.4584 919 Park Place']

Finally, split each entry into a list with first name, last name,
telephone number, and address.  We use the ‘maxsplit’ parameter of *note
split(): 2a2. because the address has spaces, our splitting pattern, in
it:

     >>> [re.split(":? ", entry, maxsplit=3) for entry in entries]
     [['Ross', 'McFluff', '834.345.1254', '155 Elm Street'],
     ['Ronald', 'Heathmore', '892.345.3428', '436 Finley Avenue'],
     ['Frank', 'Burger', '925.541.7625', '662 South Dogwood Way'],
     ['Heather', 'Albrecht', '548.326.4584', '919 Park Place']]

The ‘:?’ pattern matches the colon after the last name, so that it does
not occur in the result list.  With a ‘maxsplit’ of ‘4’, we could
separate the house number from the street name:

     >>> [re.split(":? ", entry, maxsplit=4) for entry in entries]
     [['Ross', 'McFluff', '834.345.1254', '155', 'Elm Street'],
     ['Ronald', 'Heathmore', '892.345.3428', '436', 'Finley Avenue'],
     ['Frank', 'Burger', '925.541.7625', '662', 'South Dogwood Way'],
     ['Heather', 'Albrecht', '548.326.4584', '919', 'Park Place']]


File: python.info,  Node: Text Munging,  Next: Finding all Adverbs,  Prev: Making a Phonebook,  Up: Regular Expression Examples

5.6.2.13 Text Munging
.....................

*note sub(): 2a3. replaces every occurrence of a pattern with a string
or the result of a function.  This example demonstrates using ‘sub()’
with a function to “munge” text, or randomize the order of all the
characters in each word of a sentence except for the first and last
characters:

     >>> def repl(m):
     ...     inner_word = list(m.group(2))
     ...     random.shuffle(inner_word)
     ...     return m.group(1) + "".join(inner_word) + m.group(3)
     ...
     >>> text = "Professor Abdolmalek, please report your absences promptly."
     >>> re.sub(r"(\w)(\w+)(\w)", repl, text)
     'Poefsrosr Aealmlobdk, pslaee reorpt your abnseces plmrptoy.'
     >>> re.sub(r"(\w)(\w+)(\w)", repl, text)
     'Pofsroser Aodlambelk, plasee reoprt yuor asnebces potlmrpy.'


File: python.info,  Node: Finding all Adverbs,  Next: Finding all Adverbs and their Positions,  Prev: Text Munging,  Up: Regular Expression Examples

5.6.2.14 Finding all Adverbs
............................

*note findall(): 1065. matches 'all' occurrences of a pattern, not just
the first one as *note search(): 1272. does.  For example, if a writer
wanted to find all of the adverbs in some text, they might use
‘findall()’ in the following manner:

     >>> text = "He was carefully disguised but captured quickly by police."
     >>> re.findall(r"\w+ly\b", text)
     ['carefully', 'quickly']


File: python.info,  Node: Finding all Adverbs and their Positions,  Next: Raw String Notation,  Prev: Finding all Adverbs,  Up: Regular Expression Examples

5.6.2.15 Finding all Adverbs and their Positions
................................................

If one wants more information about all matches of a pattern than the
matched text, *note finditer(): 1549. is useful as it provides *note
Match: cee. objects instead of strings.  Continuing with the previous
example, if a writer wanted to find all of the adverbs 'and their
positions' in some text, they would use ‘finditer()’ in the following
manner:

     >>> text = "He was carefully disguised but captured quickly by police."
     >>> for m in re.finditer(r"\w+ly\b", text):
     ...     print('%02d-%02d: %s' % (m.start(), m.end(), m.group(0)))
     07-16: carefully
     40-47: quickly


File: python.info,  Node: Raw String Notation,  Next: Writing a Tokenizer,  Prev: Finding all Adverbs and their Positions,  Up: Regular Expression Examples

5.6.2.16 Raw String Notation
............................

Raw string notation (‘r"text"’) keeps regular expressions sane.  Without
it, every backslash (‘'\'’) in a regular expression would have to be
prefixed with another one to escape it.  For example, the two following
lines of code are functionally identical:

     >>> re.match(r"\W(.)\1\W", " ff ")
     <re.Match object; span=(0, 4), match=' ff '>
     >>> re.match("\\W(.)\\1\\W", " ff ")
     <re.Match object; span=(0, 4), match=' ff '>

When one wants to match a literal backslash, it must be escaped in the
regular expression.  With raw string notation, this means ‘r"\\"’.
Without raw string notation, one must use ‘"\\\\"’, making the following
lines of code functionally identical:

     >>> re.match(r"\\", r"\\")
     <re.Match object; span=(0, 1), match='\\'>
     >>> re.match("\\\\", r"\\")
     <re.Match object; span=(0, 1), match='\\'>


File: python.info,  Node: Writing a Tokenizer,  Prev: Raw String Notation,  Up: Regular Expression Examples

5.6.2.17 Writing a Tokenizer
............................

A tokenizer or scanner(1) analyzes a string to categorize groups of
characters.  This is a useful first step in writing a compiler or
interpreter.

The text categories are specified with regular expressions.  The
technique is to combine those into a single master regular expression
and to loop over successive matches:

     from typing import NamedTuple
     import re

     class Token(NamedTuple):
         type: str
         value: str
         line: int
         column: int

     def tokenize(code):
         keywords = {'IF', 'THEN', 'ENDIF', 'FOR', 'NEXT', 'GOSUB', 'RETURN'}
         token_specification = [
             ('NUMBER',   r'\d+(\.\d*)?'),  # Integer or decimal number
             ('ASSIGN',   r':='),           # Assignment operator
             ('END',      r';'),            # Statement terminator
             ('ID',       r'[A-Za-z]+'),    # Identifiers
             ('OP',       r'[+\-*/]'),      # Arithmetic operators
             ('NEWLINE',  r'\n'),           # Line endings
             ('SKIP',     r'[ \t]+'),       # Skip over spaces and tabs
             ('MISMATCH', r'.'),            # Any other character
         ]
         tok_regex = '|'.join('(?P<%s>%s)' % pair for pair in token_specification)
         line_num = 1
         line_start = 0
         for mo in re.finditer(tok_regex, code):
             kind = mo.lastgroup
             value = mo.group()
             column = mo.start() - line_start
             if kind == 'NUMBER':
                 value = float(value) if '.' in value else int(value)
             elif kind == 'ID' and value in keywords:
                 kind = value
             elif kind == 'NEWLINE':
                 line_start = mo.end()
                 line_num += 1
                 continue
             elif kind == 'SKIP':
                 continue
             elif kind == 'MISMATCH':
                 raise RuntimeError(f'{value!r} unexpected on line {line_num}')
             yield Token(kind, value, line_num, column)

     statements = '''
         IF quantity THEN
             total := total + price * quantity;
             tax := price * 0.05;
         ENDIF;
     '''

     for token in tokenize(statements):
         print(token)

The tokenizer produces the following output:

     Token(type='IF', value='IF', line=2, column=4)
     Token(type='ID', value='quantity', line=2, column=7)
     Token(type='THEN', value='THEN', line=2, column=16)
     Token(type='ID', value='total', line=3, column=8)
     Token(type='ASSIGN', value=':=', line=3, column=14)
     Token(type='ID', value='total', line=3, column=17)
     Token(type='OP', value='+', line=3, column=23)
     Token(type='ID', value='price', line=3, column=25)
     Token(type='OP', value='*', line=3, column=31)
     Token(type='ID', value='quantity', line=3, column=33)
     Token(type='END', value=';', line=3, column=41)
     Token(type='ID', value='tax', line=4, column=8)
     Token(type='ASSIGN', value=':=', line=4, column=12)
     Token(type='ID', value='price', line=4, column=15)
     Token(type='OP', value='*', line=4, column=21)
     Token(type='NUMBER', value=0.05, line=4, column=23)
     Token(type='END', value=';', line=4, column=27)
     Token(type='ENDIF', value='ENDIF', line=5, column=4)
     Token(type='END', value=';', line=5, column=9)

(Frie09) Friedl, Jeffrey.  Mastering Regular Expressions.  3rd ed.,
O’Reilly Media, 2009.  The third edition of the book no longer covers
Python at all, but the first edition covered writing good regular
expression patterns in great detail.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Lexical_analysis


File: python.info,  Node: difflib — Helpers for computing deltas,  Next: textwrap — Text wrapping and filling,  Prev: re — Regular expression operations,  Up: Text Processing Services

5.6.3 ‘difflib’ — Helpers for computing deltas
----------------------------------------------

'Source code:' Lib/difflib.py(1)

__________________________________________________________________

This module provides classes and functions for comparing sequences.  It
can be used for example, for comparing files, and can produce
information about file differences in various formats, including HTML
and context and unified diffs.  For comparing directories and files, see
also, the *note filecmp: 5a. module.

 -- Class: difflib.SequenceMatcher

     This is a flexible class for comparing pairs of sequences of any
     type, so long as the sequence elements are *note hashable: 613.
     The basic algorithm predates, and is a little fancier than, an
     algorithm published in the late 1980’s by Ratcliff and Obershelp
     under the hyperbolic name “gestalt pattern matching.” The idea is
     to find the longest contiguous matching subsequence that contains
     no “junk” elements; these “junk” elements are ones that are
     uninteresting in some sense, such as blank lines or whitespace.
     (Handling junk is an extension to the Ratcliff and Obershelp
     algorithm.)  The same idea is then applied recursively to the
     pieces of the sequences to the left and to the right of the
     matching subsequence.  This does not yield minimal edit sequences,
     but does tend to yield matches that “look right” to people.

     'Timing:' The basic Ratcliff-Obershelp algorithm is cubic time in
     the worst case and quadratic time in the expected case.  *note
     SequenceMatcher: 1054. is quadratic time for the worst case and has
     expected-case behavior dependent in a complicated way on how many
     elements the sequences have in common; best case time is linear.

     'Automatic junk heuristic:' *note SequenceMatcher: 1054. supports a
     heuristic that automatically treats certain sequence items as junk.
     The heuristic counts how many times each individual item appears in
     the sequence.  If an item’s duplicates (after the first one)
     account for more than 1% of the sequence and the sequence is at
     least 200 items long, this item is marked as “popular” and is
     treated as junk for the purpose of sequence matching.  This
     heuristic can be turned off by setting the ‘autojunk’ argument to
     ‘False’ when creating the ‘SequenceMatcher’.

     Changed in version 3.2: Added the 'autojunk' parameter.

 -- Class: difflib.Differ

     This is a class for comparing sequences of lines of text, and
     producing human-readable differences or deltas.  Differ uses *note
     SequenceMatcher: 1054. both to compare sequences of lines, and to
     compare sequences of characters within similar (near-matching)
     lines.

     Each line of a *note Differ: 24e2. delta begins with a two-letter
     code:

     Code           Meaning
                    
     ---------------------------------------------------------------
                    
     ‘'- '’         line unique to sequence 1
                    
                    
     ‘'+ '’         line unique to sequence 2
                    
                    
     ‘' '’          line common to both sequences
                    
                    
     ‘'? '’         line not present in either input sequence
                    

     Lines beginning with ‘‘?’’ attempt to guide the eye to intraline
     differences, and were not present in either input sequence.  These
     lines can be confusing if the sequences contain whitespace
     characters, such as spaces, tabs or line breaks.

 -- Class: difflib.HtmlDiff

     This class can be used to create an HTML table (or a complete HTML
     file containing the table) showing a side by side, line by line
     comparison of text with inter-line and intra-line change
     highlights.  The table can be generated in either full or
     contextual difference mode.

     The constructor for this class is:

      -- Method: __init__ (tabsize=8, wrapcolumn=None, linejunk=None,
               charjunk=IS_CHARACTER_JUNK)

          Initializes instance of ‘HtmlDiff’.

          'tabsize' is an optional keyword argument to specify tab stop
          spacing and defaults to ‘8’.

          'wrapcolumn' is an optional keyword to specify column number
          where lines are broken and wrapped, defaults to ‘None’ where
          lines are not wrapped.

          'linejunk' and 'charjunk' are optional keyword arguments
          passed into *note ndiff(): 24e4. (used by ‘HtmlDiff’ to
          generate the side by side HTML differences).  See ‘ndiff()’
          documentation for argument default values and descriptions.

     The following methods are public:

      -- Method: make_file (fromlines, tolines, fromdesc='', todesc='',
               context=False, numlines=5, *, charset='utf-8')

          Compares 'fromlines' and 'tolines' (lists of strings) and
          returns a string which is a complete HTML file containing a
          table showing line by line differences with inter-line and
          intra-line changes highlighted.

          'fromdesc' and 'todesc' are optional keyword arguments to
          specify from/to file column header strings (both default to an
          empty string).

          'context' and 'numlines' are both optional keyword arguments.
          Set 'context' to ‘True’ when contextual differences are to be
          shown, else the default is ‘False’ to show the full files.
          'numlines' defaults to ‘5’.  When 'context' is ‘True’
          'numlines' controls the number of context lines which surround
          the difference highlights.  When 'context' is ‘False’
          'numlines' controls the number of lines which are shown before
          a difference highlight when using the “next” hyperlinks
          (setting to zero would cause the “next” hyperlinks to place
          the next difference highlight at the top of the browser
          without any leading context).

               Note: 'fromdesc' and 'todesc' are interpreted as
               unescaped HTML and should be properly escaped while
               receiving input from untrusted sources.

          Changed in version 3.5: 'charset' keyword-only argument was
          added.  The default charset of HTML document changed from
          ‘'ISO-8859-1'’ to ‘'utf-8'’.

      -- Method: make_table (fromlines, tolines, fromdesc='', todesc='',
               context=False, numlines=5)

          Compares 'fromlines' and 'tolines' (lists of strings) and
          returns a string which is a complete HTML table showing line
          by line differences with inter-line and intra-line changes
          highlighted.

          The arguments for this method are the same as those for the
          *note make_file(): e21. method.

 -- Function: difflib.context_diff (a, b, fromfile='', tofile='',
          fromfiledate='', tofiledate='', n=3, lineterm='\n')

     Compare 'a' and 'b' (lists of strings); return a delta (a *note
     generator: 109f. generating the delta lines) in context diff
     format.

     Context diffs are a compact way of showing just the lines that have
     changed plus a few lines of context.  The changes are shown in a
     before/after style.  The number of context lines is set by 'n'
     which defaults to three.

     By default, the diff control lines (those with ‘***’ or ‘---’) are
     created with a trailing newline.  This is helpful so that inputs
     created from *note io.IOBase.readlines(): 24e7. result in diffs
     that are suitable for use with *note io.IOBase.writelines(): 15c5.
     since both the inputs and outputs have trailing newlines.

     For inputs that do not have trailing newlines, set the 'lineterm'
     argument to ‘""’ so that the output will be uniformly newline free.

     The context diff format normally has a header for filenames and
     modification times.  Any or all of these may be specified using
     strings for 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
     The modification times are normally expressed in the ISO 8601
     format.  If not specified, the strings default to blanks.

          >>> import sys
          >>> from difflib import *
          >>> s1 = ['bacon\n', 'eggs\n', 'ham\n', 'guido\n']
          >>> s2 = ['python\n', 'eggy\n', 'hamster\n', 'guido\n']
          >>> sys.stdout.writelines(context_diff(s1, s2, fromfile='before.py',
          ...                        tofile='after.py'))
          *** before.py
          --- after.py
          ***************
          *** 1,4 ****
          ! bacon
          ! eggs
          ! ham
            guido
          --- 1,4 ----
          ! python
          ! eggy
          ! hamster
            guido

     See *note A command-line interface to difflib: 24e8. for a more
     detailed example.

 -- Function: difflib.get_close_matches (word, possibilities, n=3,
          cutoff=0.6)

     Return a list of the best “good enough” matches.  'word' is a
     sequence for which close matches are desired (typically a string),
     and 'possibilities' is a list of sequences against which to match
     'word' (typically a list of strings).

     Optional argument 'n' (default ‘3’) is the maximum number of close
     matches to return; 'n' must be greater than ‘0’.

     Optional argument 'cutoff' (default ‘0.6’) is a float in the range
     [0, 1].  Possibilities that don’t score at least that similar to
     'word' are ignored.

     The best (no more than 'n') matches among the possibilities are
     returned in a list, sorted by similarity score, most similar first.

          >>> get_close_matches('appel', ['ape', 'apple', 'peach', 'puppy'])
          ['apple', 'ape']
          >>> import keyword
          >>> get_close_matches('wheel', keyword.kwlist)
          ['while']
          >>> get_close_matches('pineapple', keyword.kwlist)
          []
          >>> get_close_matches('accept', keyword.kwlist)
          ['except']

 -- Function: difflib.ndiff (a, b, linejunk=None,
          charjunk=IS_CHARACTER_JUNK)

     Compare 'a' and 'b' (lists of strings); return a *note Differ:
     24e2.-style delta (a *note generator: 109f. generating the delta
     lines).

     Optional keyword parameters 'linejunk' and 'charjunk' are filtering
     functions (or ‘None’):

     'linejunk': A function that accepts a single string argument, and
     returns true if the string is junk, or false if not.  The default
     is ‘None’.  There is also a module-level function *note
     IS_LINE_JUNK(): 24ea, which filters out lines without visible
     characters, except for at most one hash character (‘'#'’) – however
     the underlying *note SequenceMatcher: 1054. class does a dynamic
     analysis of which lines are so frequent as to constitute noise, and
     this usually works better than using this function.

     'charjunk': A function that accepts a character (a string of length
     1), and returns if the character is junk, or false if not.  The
     default is module-level function *note IS_CHARACTER_JUNK(): 24eb,
     which filters out whitespace characters (a blank or tab; it’s a bad
     idea to include newline in this!).

          >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(keepends=True),
          ...              'ore\ntree\nemu\n'.splitlines(keepends=True))
          >>> print(''.join(diff), end="")
          - one
          ?  ^
          + ore
          ?  ^
          - two
          - three
          ?  -
          + tree
          + emu

 -- Function: difflib.restore (sequence, which)

     Return one of the two sequences that generated a delta.

     Given a 'sequence' produced by *note Differ.compare(): 24ed. or
     *note ndiff(): 24e4, extract lines originating from file 1 or 2
     (parameter 'which'), stripping off line prefixes.

     Example:

          >>> diff = ndiff('one\ntwo\nthree\n'.splitlines(keepends=True),
          ...              'ore\ntree\nemu\n'.splitlines(keepends=True))
          >>> diff = list(diff) # materialize the generated delta into a list
          >>> print(''.join(restore(diff, 1)), end="")
          one
          two
          three
          >>> print(''.join(restore(diff, 2)), end="")
          ore
          tree
          emu

 -- Function: difflib.unified_diff (a, b, fromfile='', tofile='',
          fromfiledate='', tofiledate='', n=3, lineterm='\n')

     Compare 'a' and 'b' (lists of strings); return a delta (a *note
     generator: 109f. generating the delta lines) in unified diff
     format.

     Unified diffs are a compact way of showing just the lines that have
     changed plus a few lines of context.  The changes are shown in an
     inline style (instead of separate before/after blocks).  The number
     of context lines is set by 'n' which defaults to three.

     By default, the diff control lines (those with ‘---’, ‘+++’, or
     ‘@@’) are created with a trailing newline.  This is helpful so that
     inputs created from *note io.IOBase.readlines(): 24e7. result in
     diffs that are suitable for use with *note io.IOBase.writelines():
     15c5. since both the inputs and outputs have trailing newlines.

     For inputs that do not have trailing newlines, set the 'lineterm'
     argument to ‘""’ so that the output will be uniformly newline free.

     The unified diff format normally has a header for filenames and
     modification times.  Any or all of these may be specified using
     strings for 'fromfile', 'tofile', 'fromfiledate', and 'tofiledate'.
     The modification times are normally expressed in the ISO 8601
     format.  If not specified, the strings default to blanks.

          >>> s1 = ['bacon\n', 'eggs\n', 'ham\n', 'guido\n']
          >>> s2 = ['python\n', 'eggy\n', 'hamster\n', 'guido\n']
          >>> sys.stdout.writelines(unified_diff(s1, s2, fromfile='before.py', tofile='after.py'))
          --- before.py
          +++ after.py
          @@ -1,4 +1,4 @@
          -bacon
          -eggs
          -ham
          +python
          +eggy
          +hamster
           guido

     See *note A command-line interface to difflib: 24e8. for a more
     detailed example.

 -- Function: difflib.diff_bytes (dfunc, a, b, fromfile=b'', tofile=b'',
          fromfiledate=b'', tofiledate=b'', n=3, lineterm=b'\n')

     Compare 'a' and 'b' (lists of bytes objects) using 'dfunc'; yield a
     sequence of delta lines (also bytes) in the format returned by
     'dfunc'.  'dfunc' must be a callable, typically either *note
     unified_diff(): 24ee. or *note context_diff(): 24e6.

     Allows you to compare data with unknown or inconsistent encoding.
     All inputs except 'n' must be bytes objects, not str.  Works by
     losslessly converting all inputs (except 'n') to str, and calling
     ‘dfunc(a, b, fromfile, tofile, fromfiledate, tofiledate, n,
     lineterm)’.  The output of 'dfunc' is then converted back to bytes,
     so the delta lines that you receive have the same
     unknown/inconsistent encodings as 'a' and 'b'.

     Added in version 3.5.

 -- Function: difflib.IS_LINE_JUNK (line)

     Return ‘True’ for ignorable lines.  The line 'line' is ignorable if
     'line' is blank or contains a single ‘'#'’, otherwise it is not
     ignorable.  Used as a default for parameter 'linejunk' in *note
     ndiff(): 24e4. in older versions.

 -- Function: difflib.IS_CHARACTER_JUNK (ch)

     Return ‘True’ for ignorable characters.  The character 'ch' is
     ignorable if 'ch' is a space or tab, otherwise it is not ignorable.
     Used as a default for parameter 'charjunk' in *note ndiff(): 24e4.

See also
........

Pattern Matching: The Gestalt Approach(2)

     Discussion of a similar algorithm by John W. Ratcliff and D. E.
     Metzener.  This was published in Dr.  Dobb’s Journal in July, 1988.

* Menu:

* SequenceMatcher objects::
* SequenceMatcher examples::
* Differ objects::
* Differ example::
* A command-line interface to difflib::
* ndiff example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/difflib.py

   (2) 
https://jacobfilipp.com/DrDobbs/articles/DDJ/1988/8807/8807c/8807c.htm


File: python.info,  Node: SequenceMatcher objects,  Next: SequenceMatcher examples,  Up: difflib — Helpers for computing deltas

5.6.3.1 SequenceMatcher objects
...............................

The *note SequenceMatcher: 1054. class has this constructor:

 -- Class: difflib.SequenceMatcher (isjunk=None, a='', b='',
          autojunk=True)

     Optional argument 'isjunk' must be ‘None’ (the default) or a
     one-argument function that takes a sequence element and returns
     true if and only if the element is “junk” and should be ignored.
     Passing ‘None’ for 'isjunk' is equivalent to passing ‘lambda x:
     False’; in other words, no elements are ignored.  For example,
     pass:

          lambda x: x in " \t"

     if you’re comparing lines as sequences of characters, and don’t
     want to synch up on blanks or hard tabs.

     The optional arguments 'a' and 'b' are sequences to be compared;
     both default to empty strings.  The elements of both sequences must
     be *note hashable: 613.

     The optional argument 'autojunk' can be used to disable the
     automatic junk heuristic.

     Changed in version 3.2: Added the 'autojunk' parameter.

     SequenceMatcher objects get three data attributes: 'bjunk' is the
     set of elements of 'b' for which 'isjunk' is ‘True’; 'bpopular' is
     the set of non-junk elements considered popular by the heuristic
     (if it is not disabled); 'b2j' is a dict mapping the remaining
     elements of 'b' to a list of positions where they occur.  All three
     are reset whenever 'b' is reset with *note set_seqs(): 24f1. or
     *note set_seq2(): 24f2.

     Added in version 3.2: The 'bjunk' and 'bpopular' attributes.

     ‘SequenceMatcher’ objects have the following methods:

      -- Method: set_seqs (a, b)

          Set the two sequences to be compared.

     ‘SequenceMatcher’ computes and caches detailed information about
     the second sequence, so if you want to compare one sequence against
     many sequences, use *note set_seq2(): 24f2. to set the commonly
     used sequence once and call *note set_seq1(): 24f3. repeatedly,
     once for each of the other sequences.

      -- Method: set_seq1 (a)

          Set the first sequence to be compared.  The second sequence to
          be compared is not changed.

      -- Method: set_seq2 (b)

          Set the second sequence to be compared.  The first sequence to
          be compared is not changed.

      -- Method: find_longest_match (alo=0, ahi=None, blo=0, bhi=None)

          Find longest matching block in ‘a[alo:ahi]’ and ‘b[blo:bhi]’.

          If 'isjunk' was omitted or ‘None’, ‘find_longest_match()’
          returns ‘(i, j, k)’ such that ‘a[i:i+k]’ is equal to
          ‘b[j:j+k]’, where ‘alo <= i <= i+k <= ahi’ and ‘blo <= j <=
          j+k <= bhi’.  For all ‘(i', j', k')’ meeting those conditions,
          the additional conditions ‘k >= k'’, ‘i <= i'’, and if ‘i ==
          i'’, ‘j <= j'’ are also met.  In other words, of all maximal
          matching blocks, return one that starts earliest in 'a', and
          of all those maximal matching blocks that start earliest in
          'a', return the one that starts earliest in 'b'.

               >>> s = SequenceMatcher(None, " abcd", "abcd abcd")
               >>> s.find_longest_match(0, 5, 0, 9)
               Match(a=0, b=4, size=5)

          If 'isjunk' was provided, first the longest matching block is
          determined as above, but with the additional restriction that
          no junk element appears in the block.  Then that block is
          extended as far as possible by matching (only) junk elements
          on both sides.  So the resulting block never matches on junk
          except as identical junk happens to be adjacent to an
          interesting match.

          Here’s the same example as before, but considering blanks to
          be junk.  That prevents ‘' abcd'’ from matching the ‘' abcd'’
          at the tail end of the second sequence directly.  Instead only
          the ‘'abcd'’ can match, and matches the leftmost ‘'abcd'’ in
          the second sequence:

               >>> s = SequenceMatcher(lambda x: x==" ", " abcd", "abcd abcd")
               >>> s.find_longest_match(0, 5, 0, 9)
               Match(a=1, b=0, size=4)

          If no blocks match, this returns ‘(alo, blo, 0)’.

          This method returns a *note named tuple: 651. ‘Match(a, b,
          size)’.

          Changed in version 3.9: Added default arguments.

      -- Method: get_matching_blocks ()

          Return list of triples describing non-overlapping matching
          subsequences.  Each triple is of the form ‘(i, j, n)’, and
          means that ‘a[i:i+n] == b[j:j+n]’.  The triples are
          monotonically increasing in 'i' and 'j'.

          The last triple is a dummy, and has the value ‘(len(a),
          len(b), 0)’.  It is the only triple with ‘n == 0’.  If ‘(i, j,
          n)’ and ‘(i', j', n')’ are adjacent triples in the list, and
          the second is not the last triple in the list, then ‘i+n < i'’
          or ‘j+n < j'’; in other words, adjacent triples always
          describe non-adjacent equal blocks.

               >>> s = SequenceMatcher(None, "abxcd", "abcd")
               >>> s.get_matching_blocks()
               [Match(a=0, b=0, size=2), Match(a=3, b=2, size=2), Match(a=5, b=4, size=0)]

      -- Method: get_opcodes ()

          Return list of 5-tuples describing how to turn 'a' into 'b'.
          Each tuple is of the form ‘(tag, i1, i2, j1, j2)’.  The first
          tuple has ‘i1 == j1 == 0’, and remaining tuples have 'i1'
          equal to the 'i2' from the preceding tuple, and, likewise,
          'j1' equal to the previous 'j2'.

          The 'tag' values are strings, with these meanings:

          Value               Meaning
                              
          ----------------------------------------------------------------------
                              
          ‘'replace'’         ‘a[i1:i2]’ should be replaced by ‘b[j1:j2]’.
                              
                              
          ‘'delete'’          ‘a[i1:i2]’ should be deleted.  Note that ‘j1 ==
                              j2’ in this case.
                              
                              
          ‘'insert'’          ‘b[j1:j2]’ should be inserted at ‘a[i1:i1]’.
                              Note that ‘i1 == i2’ in this case.
                              
                              
          ‘'equal'’           ‘a[i1:i2] == b[j1:j2]’ (the sub-sequences are
                              equal).
                              

          For example:

               >>> a = "qabxcd"
               >>> b = "abycdf"
               >>> s = SequenceMatcher(None, a, b)
               >>> for tag, i1, i2, j1, j2 in s.get_opcodes():
               ...     print('{:7}   a[{}:{}] --> b[{}:{}] {!r:>8} --> {!r}'.format(
               ...         tag, i1, i2, j1, j2, a[i1:i2], b[j1:j2]))
               delete    a[0:1] --> b[0:0]      'q' --> ''
               equal     a[1:3] --> b[0:2]     'ab' --> 'ab'
               replace   a[3:4] --> b[2:3]      'x' --> 'y'
               equal     a[4:6] --> b[3:5]     'cd' --> 'cd'
               insert    a[6:6] --> b[5:6]       '' --> 'f'

      -- Method: get_grouped_opcodes (n=3)

          Return a *note generator: 109f. of groups with up to 'n' lines
          of context.

          Starting with the groups returned by *note get_opcodes():
          24f5, this method splits out smaller change clusters and
          eliminates intervening ranges which have no changes.

          The groups are returned in the same format as *note
          get_opcodes(): 24f5.

      -- Method: ratio ()

          Return a measure of the sequences’ similarity as a float in
          the range [0, 1].

          Where T is the total number of elements in both sequences, and
          M is the number of matches, this is 2.0*M / T. Note that this
          is ‘1.0’ if the sequences are identical, and ‘0.0’ if they
          have nothing in common.

          This is expensive to compute if *note get_matching_blocks():
          24f4. or *note get_opcodes(): 24f5. hasn’t already been
          called, in which case you may want to try *note quick_ratio():
          24f8. or *note real_quick_ratio(): 24f9. first to get an upper
          bound.

               Note: Caution: The result of a ‘ratio()’ call may depend
               on the order of the arguments.  For instance:

                    >>> SequenceMatcher(None, 'tide', 'diet').ratio()
                    0.25
                    >>> SequenceMatcher(None, 'diet', 'tide').ratio()
                    0.5

      -- Method: quick_ratio ()

          Return an upper bound on *note ratio(): 24f7. relatively
          quickly.

      -- Method: real_quick_ratio ()

          Return an upper bound on *note ratio(): 24f7. very quickly.

The three methods that return the ratio of matching to total characters
can give different results due to differing levels of approximation,
although *note quick_ratio(): 24f8. and *note real_quick_ratio(): 24f9.
are always at least as large as *note ratio(): 24f7.:

     >>> s = SequenceMatcher(None, "abcd", "bcde")
     >>> s.ratio()
     0.75
     >>> s.quick_ratio()
     0.75
     >>> s.real_quick_ratio()
     1.0


File: python.info,  Node: SequenceMatcher examples,  Next: Differ objects,  Prev: SequenceMatcher objects,  Up: difflib — Helpers for computing deltas

5.6.3.2 SequenceMatcher examples
................................

This example compares two strings, considering blanks to be “junk”:

     >>> s = SequenceMatcher(lambda x: x == " ",
     ...                     "private Thread currentThread;",
     ...                     "private volatile Thread currentThread;")

*note ratio(): 24f7. returns a float in [0, 1], measuring the similarity
of the sequences.  As a rule of thumb, a ‘ratio()’ value over 0.6 means
the sequences are close matches:

     >>> print(round(s.ratio(), 3))
     0.866

If you’re only interested in where the sequences match, *note
get_matching_blocks(): 24f4. is handy:

     >>> for block in s.get_matching_blocks():
     ...     print("a[%d] and b[%d] match for %d elements" % block)
     a[0] and b[0] match for 8 elements
     a[8] and b[17] match for 21 elements
     a[29] and b[38] match for 0 elements

Note that the last tuple returned by *note get_matching_blocks(): 24f4.
is always a dummy, ‘(len(a), len(b), 0)’, and this is the only case in
which the last tuple element (number of elements matched) is ‘0’.

If you want to know how to change the first sequence into the second,
use *note get_opcodes(): 24f5.:

     >>> for opcode in s.get_opcodes():
     ...     print("%6s a[%d:%d] b[%d:%d]" % opcode)
      equal a[0:8] b[0:8]
     insert a[8:8] b[8:17]
      equal a[8:29] b[17:38]

See also
........

   * The *note get_close_matches(): 24e9. function in this module which
     shows how simple code building on *note SequenceMatcher: 1054. can
     be used to do useful work.

   * Simple version control recipe(1) for a small application built with
     *note SequenceMatcher: 1054.

   ---------- Footnotes ----------

   (1) 
https://code.activestate.com/recipes/576729-simple-version-control/


File: python.info,  Node: Differ objects,  Next: Differ example,  Prev: SequenceMatcher examples,  Up: difflib — Helpers for computing deltas

5.6.3.3 Differ objects
......................

Note that *note Differ: 24e2.-generated deltas make no claim to be
'minimal' diffs.  To the contrary, minimal diffs are often
counter-intuitive, because they synch up anywhere possible, sometimes
accidental matches 100 pages apart.  Restricting synch points to
contiguous matches preserves some notion of locality, at the occasional
cost of producing a longer diff.

The *note Differ: 24e2. class has this constructor:

 -- Class: difflib.Differ (linejunk=None, charjunk=None)

     Optional keyword parameters 'linejunk' and 'charjunk' are for
     filter functions (or ‘None’):

     'linejunk': A function that accepts a single string argument, and
     returns true if the string is junk.  The default is ‘None’, meaning
     that no line is considered junk.

     'charjunk': A function that accepts a single character argument (a
     string of length 1), and returns true if the character is junk.
     The default is ‘None’, meaning that no character is considered
     junk.

     These junk-filtering functions speed up matching to find
     differences and do not cause any differing lines or characters to
     be ignored.  Read the description of the *note
     find_longest_match(): 1af2. method’s 'isjunk' parameter for an
     explanation.

     ‘Differ’ objects are used (deltas generated) via a single method:

      -- Method: compare (a, b)

          Compare two sequences of lines, and generate the delta (a
          sequence of lines).

          Each sequence must contain individual single-line strings
          ending with newlines.  Such sequences can be obtained from the
          *note readlines(): 24e7. method of file-like objects.  The
          delta generated also consists of newline-terminated strings,
          ready to be printed as-is via the *note writelines(): 15c5.
          method of a file-like object.


File: python.info,  Node: Differ example,  Next: A command-line interface to difflib,  Prev: Differ objects,  Up: difflib — Helpers for computing deltas

5.6.3.4 Differ example
......................

This example compares two texts.  First we set up the texts, sequences
of individual single-line strings ending with newlines (such sequences
can also be obtained from the *note readlines(): 24e7. method of
file-like objects):

     >>> text1 = '''  1. Beautiful is better than ugly.
     ...   2. Explicit is better than implicit.
     ...   3. Simple is better than complex.
     ...   4. Complex is better than complicated.
     ... '''.splitlines(keepends=True)
     >>> len(text1)
     4
     >>> text1[0][-1]
     '\n'
     >>> text2 = '''  1. Beautiful is better than ugly.
     ...   3.   Simple is better than complex.
     ...   4. Complicated is better than complex.
     ...   5. Flat is better than nested.
     ... '''.splitlines(keepends=True)

Next we instantiate a Differ object:

     >>> d = Differ()

Note that when instantiating a *note Differ: 24e2. object we may pass
functions to filter out line and character “junk.” See the *note
Differ(): 24e2. constructor for details.

Finally, we compare the two:

     >>> result = list(d.compare(text1, text2))

‘result’ is a list of strings, so let’s pretty-print it:

     >>> from pprint import pprint
     >>> pprint(result)
     ['    1. Beautiful is better than ugly.\n',
      '-   2. Explicit is better than implicit.\n',
      '-   3. Simple is better than complex.\n',
      '+   3.   Simple is better than complex.\n',
      '?     ++\n',
      '-   4. Complex is better than complicated.\n',
      '?            ^                     ---- ^\n',
      '+   4. Complicated is better than complex.\n',
      '?           ++++ ^                      ^\n',
      '+   5. Flat is better than nested.\n']

As a single multi-line string it looks like this:

     >>> import sys
     >>> sys.stdout.writelines(result)
         1. Beautiful is better than ugly.
     -   2. Explicit is better than implicit.
     -   3. Simple is better than complex.
     +   3.   Simple is better than complex.
     ?     ++
     -   4. Complex is better than complicated.
     ?            ^                     ---- ^
     +   4. Complicated is better than complex.
     ?           ++++ ^                      ^
     +   5. Flat is better than nested.


File: python.info,  Node: A command-line interface to difflib,  Next: ndiff example,  Prev: Differ example,  Up: difflib — Helpers for computing deltas

5.6.3.5 A command-line interface to difflib
...........................................

This example shows how to use difflib to create a ‘diff’-like utility.

     """ Command-line interface to difflib.py providing diffs in four formats:

     * ndiff:    lists every line and highlights interline changes.
     * context:  highlights clusters of changes in a before/after format.
     * unified:  highlights clusters of changes in an inline format.
     * html:     generates side by side comparison with change highlights.

     """

     import sys, os, difflib, argparse
     import datetime as dt

     def file_mtime(path):
         t = dt.datetime.fromtimestamp(os.stat(path).st_mtime,
                                       dt.timezone.utc)
         return t.astimezone().isoformat()

     def main():

         parser = argparse.ArgumentParser()
         parser.add_argument('-c', action='store_true', default=False,
                             help='Produce a context format diff (default)')
         parser.add_argument('-u', action='store_true', default=False,
                             help='Produce a unified format diff')
         parser.add_argument('-m', action='store_true', default=False,
                             help='Produce HTML side by side diff '
                                  '(can use -c and -l in conjunction)')
         parser.add_argument('-n', action='store_true', default=False,
                             help='Produce a ndiff format diff')
         parser.add_argument('-l', '--lines', type=int, default=3,
                             help='Set number of context lines (default 3)')
         parser.add_argument('fromfile')
         parser.add_argument('tofile')
         options = parser.parse_args()

         n = options.lines
         fromfile = options.fromfile
         tofile = options.tofile

         fromdate = file_mtime(fromfile)
         todate = file_mtime(tofile)
         with open(fromfile) as ff:
             fromlines = ff.readlines()
         with open(tofile) as tf:
             tolines = tf.readlines()

         if options.u:
             diff = difflib.unified_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)
         elif options.n:
             diff = difflib.ndiff(fromlines, tolines)
         elif options.m:
             diff = difflib.HtmlDiff().make_file(fromlines,tolines,fromfile,tofile,context=options.c,numlines=n)
         else:
             diff = difflib.context_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)

         sys.stdout.writelines(diff)

     if __name__ == '__main__':
         main()


File: python.info,  Node: ndiff example,  Prev: A command-line interface to difflib,  Up: difflib — Helpers for computing deltas

5.6.3.6 ndiff example
.....................

This example shows how to use *note difflib.ndiff(): 24e4.

     """ndiff [-q] file1 file2
         or
     ndiff (-r1 | -r2) < ndiff_output > file1_or_file2

     Print a human-friendly file difference report to stdout.  Both inter-
     and intra-line differences are noted.  In the second form, recreate file1
     (-r1) or file2 (-r2) on stdout, from an ndiff report on stdin.

     In the first form, if -q ("quiet") is not specified, the first two lines
     of output are

     -: file1
     +: file2

     Each remaining line begins with a two-letter code:

         "- "    line unique to file1
         "+ "    line unique to file2
         "  "    line common to both files
         "? "    line not present in either input file

     Lines beginning with "? " attempt to guide the eye to intraline
     differences, and were not present in either input file.  These lines can be
     confusing if the source files contain tab characters.

     The first file can be recovered by retaining only lines that begin with
     "  " or "- ", and deleting those 2-character prefixes; use ndiff with -r1.

     The second file can be recovered similarly, but by retaining only "  " and
     "+ " lines; use ndiff with -r2; or, on Unix, the second file can be
     recovered by piping the output through

         sed -n '/^[+ ] /s/^..//p'
     """

     __version__ = 1, 7, 0

     import difflib, sys

     def fail(msg):
         out = sys.stderr.write
         out(msg + "\n\n")
         out(__doc__)
         return 0

     # open a file & return the file object; gripe and return 0 if it
     # couldn't be opened
     def fopen(fname):
         try:
             return open(fname)
         except IOError as detail:
             return fail("couldn't open " + fname + ": " + str(detail))

     # open two files & spray the diff to stdout; return false iff a problem
     def fcompare(f1name, f2name):
         f1 = fopen(f1name)
         f2 = fopen(f2name)
         if not f1 or not f2:
             return 0

         a = f1.readlines(); f1.close()
         b = f2.readlines(); f2.close()
         for line in difflib.ndiff(a, b):
             print(line, end=' ')

         return 1

     # crack args (sys.argv[1:] is normal) & compare;
     # return false iff a problem

     def main(args):
         import getopt
         try:
             opts, args = getopt.getopt(args, "qr:")
         except getopt.error as detail:
             return fail(str(detail))
         noisy = 1
         qseen = rseen = 0
         for opt, val in opts:
             if opt == "-q":
                 qseen = 1
                 noisy = 0
             elif opt == "-r":
                 rseen = 1
                 whichfile = val
         if qseen and rseen:
             return fail("can't specify both -q and -r")
         if rseen:
             if args:
                 return fail("no args allowed with -r option")
             if whichfile in ("1", "2"):
                 restore(whichfile)
                 return 1
             return fail("-r value must be 1 or 2")
         if len(args) != 2:
             return fail("need 2 filename args")
         f1name, f2name = args
         if noisy:
             print('-:', f1name)
             print('+:', f2name)
         return fcompare(f1name, f2name)

     # read ndiff output from stdin, and print file1 (which=='1') or
     # file2 (which=='2') to stdout

     def restore(which):
         restored = difflib.restore(sys.stdin.readlines(), which)
         sys.stdout.writelines(restored)

     if __name__ == '__main__':
         main(sys.argv[1:])


File: python.info,  Node: textwrap — Text wrapping and filling,  Next: unicodedata — Unicode Database,  Prev: difflib — Helpers for computing deltas,  Up: Text Processing Services

5.6.4 ‘textwrap’ — Text wrapping and filling
--------------------------------------------

'Source code:' Lib/textwrap.py(1)

__________________________________________________________________

The ‘textwrap’ module provides some convenience functions, as well as
*note TextWrapper: 1008, the class that does all the work.  If you’re
just wrapping or filling one or two text strings, the convenience
functions should be good enough; otherwise, you should use an instance
of ‘TextWrapper’ for efficiency.

 -- Function: textwrap.wrap (text, width=70, *, initial_indent='',
          subsequent_indent='', expand_tabs=True,
          replace_whitespace=True, fix_sentence_endings=False,
          break_long_words=True, drop_whitespace=True,
          break_on_hyphens=True, tabsize=8, max_lines=None,
          placeholder=' [...]')

     Wraps the single paragraph in 'text' (a string) so every line is at
     most 'width' characters long.  Returns a list of output lines,
     without final newlines.

     Optional keyword arguments correspond to the instance attributes of
     *note TextWrapper: 1008, documented below.

     See the *note TextWrapper.wrap(): 2505. method for additional
     details on how ‘wrap()’ behaves.

 -- Function: textwrap.fill (text, width=70, *, initial_indent='',
          subsequent_indent='', expand_tabs=True,
          replace_whitespace=True, fix_sentence_endings=False,
          break_long_words=True, drop_whitespace=True,
          break_on_hyphens=True, tabsize=8, max_lines=None,
          placeholder=' [...]')

     Wraps the single paragraph in 'text', and returns a single string
     containing the wrapped paragraph.  ‘fill()’ is shorthand for

          "\n".join(wrap(text, ...))

     In particular, ‘fill()’ accepts exactly the same keyword arguments
     as *note wrap(): 1516.

 -- Function: textwrap.shorten (text, width, *,
          fix_sentence_endings=False, break_long_words=True,
          break_on_hyphens=True, placeholder=' [...]')

     Collapse and truncate the given 'text' to fit in the given 'width'.

     First the whitespace in 'text' is collapsed (all whitespace is
     replaced by single spaces).  If the result fits in the 'width', it
     is returned.  Otherwise, enough words are dropped from the end so
     that the remaining words plus the 'placeholder' fit within 'width':

          >>> textwrap.shorten("Hello  world!", width=12)
          'Hello world!'
          >>> textwrap.shorten("Hello  world!", width=11)
          'Hello [...]'
          >>> textwrap.shorten("Hello world", width=10, placeholder="...")
          'Hello...'

     Optional keyword arguments correspond to the instance attributes of
     *note TextWrapper: 1008, documented below.  Note that the
     whitespace is collapsed before the text is passed to the
     ‘TextWrapper’ *note fill(): 1515. function, so changing the value
     of *note tabsize: 2506, *note expand_tabs: 2507, *note
     drop_whitespace: 2508, and *note replace_whitespace: 2509. will
     have no effect.

     Added in version 3.4.

 -- Function: textwrap.dedent (text)

     Remove any common leading whitespace from every line in 'text'.

     This can be used to make triple-quoted strings line up with the
     left edge of the display, while still presenting them in the source
     code in indented form.

     Note that tabs and spaces are both treated as whitespace, but they
     are not equal: the lines ‘" hello"’ and ‘"\thello"’ are considered
     to have no common leading whitespace.

     Lines containing only whitespace are ignored in the input and
     normalized to a single newline character in the output.

     For example:

          def test():
              # end first line with \ to avoid the empty line!
              s = '''\
              hello
                world
              '''
              print(repr(s))          # prints '    hello\n      world\n    '
              print(repr(dedent(s)))  # prints 'hello\n  world\n'

 -- Function: textwrap.indent (text, prefix, predicate=None)

     Add 'prefix' to the beginning of selected lines in 'text'.

     Lines are separated by calling ‘text.splitlines(True)’.

     By default, 'prefix' is added to all lines that do not consist
     solely of whitespace (including any line endings).

     For example:

          >>> s = 'hello\n\n \nworld'
          >>> indent(s, '  ')
          '  hello\n\n \n  world'

     The optional 'predicate' argument can be used to control which
     lines are indented.  For example, it is easy to add 'prefix' to
     even empty and whitespace-only lines:

          >>> print(indent(s, '+ ', lambda line: True))
          + hello
          +
          +
          + world

     Added in version 3.3.

*note wrap(): 1516, *note fill(): 1515. and *note shorten(): 100b. work
by creating a *note TextWrapper: 1008. instance and calling a single
method on it.  That instance is not reused, so for applications that
process many text strings using ‘wrap()’ and/or ‘fill()’, it may be more
efficient to create your own ‘TextWrapper’ object.

Text is preferably wrapped on whitespaces and right after the hyphens in
hyphenated words; only then will long words be broken if necessary,
unless *note TextWrapper.break_long_words: 250b. is set to false.

 -- Class: textwrap.TextWrapper (**kwargs)

     The ‘TextWrapper’ constructor accepts a number of optional keyword
     arguments.  Each keyword argument corresponds to an instance
     attribute, so for example

          wrapper = TextWrapper(initial_indent="* ")

     is the same as

          wrapper = TextWrapper()
          wrapper.initial_indent = "* "

     You can reuse the same ‘TextWrapper’ object many times, and you can
     change any of its options through direct assignment to instance
     attributes between uses.

     The ‘TextWrapper’ instance attributes (and keyword arguments to the
     constructor) are as follows:

      -- Attribute: width

          (default: ‘70’) The maximum length of wrapped lines.  As long
          as there are no individual words in the input text longer than
          *note width: 250c, ‘TextWrapper’ guarantees that no output
          line will be longer than ‘width’ characters.

      -- Attribute: expand_tabs

          (default: ‘True’) If true, then all tab characters in 'text'
          will be expanded to spaces using the *note expandtabs(): 2379.
          method of 'text'.

      -- Attribute: tabsize

          (default: ‘8’) If *note expand_tabs: 2507. is true, then all
          tab characters in 'text' will be expanded to zero or more
          spaces, depending on the current column and the given tab
          size.

          Added in version 3.3.

      -- Attribute: replace_whitespace

          (default: ‘True’) If true, after tab expansion but before
          wrapping, the *note wrap(): 1516. method will replace each
          whitespace character with a single space.  The whitespace
          characters replaced are as follows: tab, newline, vertical
          tab, formfeed, and carriage return (‘'\t\n\v\f\r'’).

               Note: If *note expand_tabs: 2507. is false and *note
               replace_whitespace: 2509. is true, each tab character
               will be replaced by a single space, which is 'not' the
               same as tab expansion.

               Note: If *note replace_whitespace: 2509. is false,
               newlines may appear in the middle of a line and cause
               strange output.  For this reason, text should be split
               into paragraphs (using *note str.splitlines(): 129d. or
               similar) which are wrapped separately.

      -- Attribute: drop_whitespace

          (default: ‘True’) If true, whitespace at the beginning and
          ending of every line (after wrapping but before indenting) is
          dropped.  Whitespace at the beginning of the paragraph,
          however, is not dropped if non-whitespace follows it.  If
          whitespace being dropped takes up an entire line, the whole
          line is dropped.

      -- Attribute: initial_indent

          (default: ‘''’) String that will be prepended to the first
          line of wrapped output.  Counts towards the length of the
          first line.  The empty string is not indented.

      -- Attribute: subsequent_indent

          (default: ‘''’) String that will be prepended to all lines of
          wrapped output except the first.  Counts towards the length of
          each line except the first.

      -- Attribute: fix_sentence_endings

          (default: ‘False’) If true, ‘TextWrapper’ attempts to detect
          sentence endings and ensure that sentences are always
          separated by exactly two spaces.  This is generally desired
          for text in a monospaced font.  However, the sentence
          detection algorithm is imperfect: it assumes that a sentence
          ending consists of a lowercase letter followed by one of
          ‘'.'’, ‘'!'’, or ‘'?'’, possibly followed by one of ‘'"'’ or
          ‘"'"’, followed by a space.  One problem with this algorithm
          is that it is unable to detect the difference between “Dr.” in

               [...] Dr. Frankenstein's monster [...]

          and “Spot.” in

               [...] See Spot. See Spot run [...]

          *note fix_sentence_endings: 250f. is false by default.

          Since the sentence detection algorithm relies on
          ‘string.lowercase’ for the definition of “lowercase letter”,
          and a convention of using two spaces after a period to
          separate sentences on the same line, it is specific to
          English-language texts.

      -- Attribute: break_long_words

          (default: ‘True’) If true, then words longer than *note width:
          250c. will be broken in order to ensure that no lines are
          longer than ‘width’.  If it is false, long words will not be
          broken, and some lines may be longer than ‘width’.  (Long
          words will be put on a line by themselves, in order to
          minimize the amount by which ‘width’ is exceeded.)

      -- Attribute: break_on_hyphens

          (default: ‘True’) If true, wrapping will occur preferably on
          whitespaces and right after hyphens in compound words, as it
          is customary in English.  If false, only whitespaces will be
          considered as potentially good places for line breaks, but you
          need to set *note break_long_words: 250b. to false if you want
          truly insecable words.  Default behaviour in previous versions
          was to always allow breaking hyphenated words.

      -- Attribute: max_lines

          (default: ‘None’) If not ‘None’, then the output will contain
          at most 'max_lines' lines, with 'placeholder' appearing at the
          end of the output.

          Added in version 3.4.

      -- Attribute: placeholder

          (default: ‘' [...]'’) String that will appear at the end of
          the output text if it has been truncated.

          Added in version 3.4.

     ‘TextWrapper’ also provides some public methods, analogous to the
     module-level convenience functions:

      -- Method: wrap (text)

          Wraps the single paragraph in 'text' (a string) so every line
          is at most *note width: 250c. characters long.  All wrapping
          options are taken from instance attributes of the
          ‘TextWrapper’ instance.  Returns a list of output lines,
          without final newlines.  If the wrapped output has no content,
          the returned list is empty.

      -- Method: fill (text)

          Wraps the single paragraph in 'text', and returns a single
          string containing the wrapped paragraph.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/textwrap.py


File: python.info,  Node: unicodedata — Unicode Database,  Next: stringprep — Internet String Preparation,  Prev: textwrap — Text wrapping and filling,  Up: Text Processing Services

5.6.5 ‘unicodedata’ — Unicode Database
--------------------------------------

__________________________________________________________________

This module provides access to the Unicode Character Database (UCD)
which defines character properties for all Unicode characters.  The data
contained in this database is compiled from the UCD version 15.1.0(1).

The module uses the same names and symbols as defined by Unicode
Standard Annex #44, "Unicode Character Database"(2).  It defines the
following functions:

See also
........

The *note Unicode HOWTO: 12ec. for more information about Unicode and
how to use this module.

 -- Function: unicodedata.lookup (name)

     Look up character by name.  If a character with the given name is
     found, return the corresponding character.  If not found, *note
     KeyError: 345. is raised.  For example:

          >>> unicodedata.lookup('LEFT CURLY BRACKET')
          '{'

     The characters returned by this function are the same as those
     produced by ‘\N’ escape sequence in string literals.  For example:

          >>> unicodedata.lookup('MIDDLE DOT') == '\N{MIDDLE DOT}'
          True

     Changed in version 3.3: Support for name aliases (3) and named
     sequences (4) has been added.

 -- Function: unicodedata.name (chr, default=None, /)

     Returns the name assigned to the character 'chr' as a string.  If
     no name is defined, 'default' is returned, or, if not given, *note
     ValueError: 202. is raised.  For example:

          >>> unicodedata.name('½')
          'VULGAR FRACTION ONE HALF'
          >>> unicodedata.name('\uFFFF', 'fallback')
          'fallback'

 -- Function: unicodedata.decimal (chr, default=None, /)

     Returns the decimal value assigned to the character 'chr' as
     integer.  If no such value is defined, 'default' is returned, or,
     if not given, *note ValueError: 202. is raised.  For example:

          >>> unicodedata.decimal('\N{ARABIC-INDIC DIGIT NINE}')
          9
          >>> unicodedata.decimal('\N{SUPERSCRIPT NINE}', -1)
          -1

 -- Function: unicodedata.digit (chr, default=None, /)

     Returns the digit value assigned to the character 'chr' as integer.
     If no such value is defined, 'default' is returned, or, if not
     given, *note ValueError: 202. is raised:

          >>> unicodedata.digit('\N{SUPERSCRIPT NINE}')
          9

 -- Function: unicodedata.numeric (chr, default=None, /)

     Returns the numeric value assigned to the character 'chr' as float.
     If no such value is defined, 'default' is returned, or, if not
     given, *note ValueError: 202. is raised:

          >>> unicodedata.numeric('½')
          0.5

 -- Function: unicodedata.category (chr)

     Returns the general category assigned to the character 'chr' as
     string.  General category names consist of two letters.  See the
     General Category Values section of the Unicode Character Database
     documentation(5) for a list of category codes.  For example:

          >>> unicodedata.category('A')  # 'L'etter, 'u'ppercase
          'Lu'

 -- Function: unicodedata.bidirectional (chr)

     Returns the bidirectional class assigned to the character 'chr' as
     string.  If no such value is defined, an empty string is returned.
     See the Bidirectional Class Values section of the Unicode Character
     Database(6) documentation for a list of bidirectional codes.  For
     example:

          >>> unicodedata.bidirectional('\N{ARABIC-INDIC DIGIT SEVEN}') # 'A'rabic, 'N'umber
          'AN'

 -- Function: unicodedata.combining (chr)

     Returns the canonical combining class assigned to the character
     'chr' as integer.  Returns ‘0’ if no combining class is defined.
     See the Canonical Combining Class Values section of the Unicode
     Character Database(7) for more information.

 -- Function: unicodedata.east_asian_width (chr)

     Returns the east asian width assigned to the character 'chr' as
     string.  For a list of widths and or more information, see the
     Unicode Standard Annex #11(8).

 -- Function: unicodedata.mirrored (chr)

     Returns the mirrored property assigned to the character 'chr' as
     integer.  Returns ‘1’ if the character has been identified as a
     “mirrored” character in bidirectional text, ‘0’ otherwise.  For
     example:

          >>> unicodedata.mirrored('>')
          1

 -- Function: unicodedata.decomposition (chr)

     Returns the character decomposition mapping assigned to the
     character 'chr' as string.  An empty string is returned in case no
     such mapping is defined.  For example:

          >>> unicodedata.decomposition('Ã')
          '0041 0303'

 -- Function: unicodedata.normalize (form, unistr)

     Return the normal form 'form' for the Unicode string 'unistr'.
     Valid values for 'form' are ‘NFC’, ‘NFKC’, ‘NFD’, and ‘NFKD’.

     The Unicode standard defines various normalization forms of a
     Unicode string, based on the definition of canonical equivalence
     and compatibility equivalence.  In Unicode, several characters can
     be expressed in various way.  For example, the character U+00C7
     (LATIN CAPITAL LETTER C WITH CEDILLA) can also be expressed as the
     sequence U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING
     CEDILLA).

     For each character, there are two normal forms: normal form C and
     normal form D. Normal form D (NFD) is also known as canonical
     decomposition, and translates each character into its decomposed
     form.  Normal form C (NFC) first applies a canonical decomposition,
     then composes pre-combined characters again.

     In addition to these two forms, there are two additional normal
     forms based on compatibility equivalence.  In Unicode, certain
     characters are supported which normally would be unified with other
     characters.  For example, U+2160 (ROMAN NUMERAL ONE) is really the
     same thing as U+0049 (LATIN CAPITAL LETTER I). However, it is
     supported in Unicode for compatibility with existing character sets
     (for example, gb2312).

     The normal form KD (NFKD) will apply the compatibility
     decomposition, that is, replace all compatibility characters with
     their equivalents.  The normal form KC (NFKC) first applies the
     compatibility decomposition, followed by the canonical composition.

     Even if two unicode strings are normalized and look the same to a
     human reader, if one has combining characters and the other
     doesn’t, they may not compare equal.

 -- Function: unicodedata.is_normalized (form, unistr)

     Return whether the Unicode string 'unistr' is in the normal form
     'form'.  Valid values for 'form' are ‘NFC’, ‘NFKC’, ‘NFD’, and
     ‘NFKD’.

     Added in version 3.8.

In addition, the module exposes the following constant:

 -- Data: unicodedata.unidata_version

     The version of the Unicode database used in this module.

 -- Data: unicodedata.ucd_3_2_0

     This is an object that has the same methods as the entire module,
     but uses the Unicode database version 3.2 instead, for applications
     that require this specific version of the Unicode database (such as
     IDNA).

   ---------- Footnotes ----------

   (1) https://www.unicode.org/Public/15.1.0/ucd

   (2) https://www.unicode.org/reports/tr44/

   (3) ‘https://www.unicode.org/Public/15.1.0/ucd/NameAliases.txt’

   (4) ‘https://www.unicode.org/Public/15.1.0/ucd/NamedSequences.txt’

   (5) 
https://www.unicode.org/reports/tr44/tr44-30.html#General_Category_Values

   (6) 
https://www.unicode.org/reports/tr44/tr44-30.html#Bidi_Class_Values

   (7) 
https://www.unicode.org/reports/tr44/tr44-30.html#Canonical_Combining_Class_Values

   (8) https://www.unicode.org/reports/tr11/tr11-41.html


File: python.info,  Node: stringprep — Internet String Preparation,  Next: readline — GNU readline interface,  Prev: unicodedata — Unicode Database,  Up: Text Processing Services

5.6.6 ‘stringprep’ — Internet String Preparation
------------------------------------------------

'Source code:' Lib/stringprep.py(1)

__________________________________________________________________

When identifying things (such as host names) in the internet, it is
often necessary to compare such identifications for “equality”.  Exactly
how this comparison is executed may depend on the application domain,
e.g.  whether it should be case-insensitive or not.  It may be also
necessary to restrict the possible identifications, to allow only
identifications consisting of “printable” characters.

RFC 3454(2) defines a procedure for “preparing” Unicode strings in
internet protocols.  Before passing strings onto the wire, they are
processed with the preparation procedure, after which they have a
certain normalized form.  The RFC defines a set of tables, which can be
combined into profiles.  Each profile must define which tables it uses,
and what other optional parts of the ‘stringprep’ procedure are part of
the profile.  One example of a ‘stringprep’ profile is ‘nameprep’, which
is used for internationalized domain names.

The module ‘stringprep’ only exposes the tables from RFC 3454(3).  As
these tables would be very large to represent as dictionaries or lists,
the module uses the Unicode character database internally.  The module
source code itself was generated using the ‘mkstringprep.py’ utility.

As a result, these tables are exposed as functions, not as data
structures.  There are two kinds of tables in the RFC: sets and
mappings.  For a set, ‘stringprep’ provides the “characteristic
function”, i.e.  a function that returns ‘True’ if the parameter is part
of the set.  For mappings, it provides the mapping function: given the
key, it returns the associated value.  Below is a list of all functions
available in the module.

 -- Function: stringprep.in_table_a1 (code)

     Determine whether 'code' is in tableA.1 (Unassigned code points in
     Unicode 3.2).

 -- Function: stringprep.in_table_b1 (code)

     Determine whether 'code' is in tableB.1 (Commonly mapped to
     nothing).

 -- Function: stringprep.map_table_b2 (code)

     Return the mapped value for 'code' according to tableB.2 (Mapping
     for case-folding used with NFKC).

 -- Function: stringprep.map_table_b3 (code)

     Return the mapped value for 'code' according to tableB.3 (Mapping
     for case-folding used with no normalization).

 -- Function: stringprep.in_table_c11 (code)

     Determine whether 'code' is in tableC.1.1 (ASCII space characters).

 -- Function: stringprep.in_table_c12 (code)

     Determine whether 'code' is in tableC.1.2 (Non-ASCII space
     characters).

 -- Function: stringprep.in_table_c11_c12 (code)

     Determine whether 'code' is in tableC.1 (Space characters, union of
     C.1.1 and C.1.2).

 -- Function: stringprep.in_table_c21 (code)

     Determine whether 'code' is in tableC.2.1 (ASCII control
     characters).

 -- Function: stringprep.in_table_c22 (code)

     Determine whether 'code' is in tableC.2.2 (Non-ASCII control
     characters).

 -- Function: stringprep.in_table_c21_c22 (code)

     Determine whether 'code' is in tableC.2 (Control characters, union
     of C.2.1 and C.2.2).

 -- Function: stringprep.in_table_c3 (code)

     Determine whether 'code' is in tableC.3 (Private use).

 -- Function: stringprep.in_table_c4 (code)

     Determine whether 'code' is in tableC.4 (Non-character code
     points).

 -- Function: stringprep.in_table_c5 (code)

     Determine whether 'code' is in tableC.5 (Surrogate codes).

 -- Function: stringprep.in_table_c6 (code)

     Determine whether 'code' is in tableC.6 (Inappropriate for plain
     text).

 -- Function: stringprep.in_table_c7 (code)

     Determine whether 'code' is in tableC.7 (Inappropriate for
     canonical representation).

 -- Function: stringprep.in_table_c8 (code)

     Determine whether 'code' is in tableC.8 (Change display properties
     or are deprecated).

 -- Function: stringprep.in_table_c9 (code)

     Determine whether 'code' is in tableC.9 (Tagging characters).

 -- Function: stringprep.in_table_d1 (code)

     Determine whether 'code' is in tableD.1 (Characters with
     bidirectional property “R” or “AL”).

 -- Function: stringprep.in_table_d2 (code)

     Determine whether 'code' is in tableD.2 (Characters with
     bidirectional property “L”).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/stringprep.py

   (2) https://datatracker.ietf.org/doc/html/rfc3454.html

   (3) https://datatracker.ietf.org/doc/html/rfc3454.html


File: python.info,  Node: readline — GNU readline interface,  Next: rlcompleter — Completion function for GNU readline,  Prev: stringprep — Internet String Preparation,  Up: Text Processing Services

5.6.7 ‘readline’ — GNU readline interface
-----------------------------------------

__________________________________________________________________

The ‘readline’ module defines a number of functions to facilitate
completion and reading/writing of history files from the Python
interpreter.  This module can be used directly, or via the *note
rlcompleter: bd. module, which supports completion of Python identifiers
at the interactive prompt.  Settings made using this module affect the
behaviour of both the interpreter’s interactive prompt and the prompts
offered by the built-in *note input(): 1320. function.

Readline keybindings may be configured via an initialization file,
typically ‘.inputrc’ in your home directory.  See Readline Init File(1)
in the GNU Readline manual for information about the format and
allowable constructs of that file, and the capabilities of the Readline
library in general.

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

*note Availability: 1ef7.: Unix.

     Note: The underlying Readline library API may be implemented by the
     ‘editline’ (‘libedit’) library instead of GNU readline.  On macOS
     the ‘readline’ module detects which library is being used at run
     time.

     The configuration file for ‘editline’ is different from that of GNU
     readline.  If you programmatically load configuration strings you
     can use *note backend: 17c0. to determine which library is being
     used.

     If you use ‘editline’/‘libedit’ readline emulation on macOS, the
     initialization file located in your home directory is named
     ‘.editrc’.  For example, the following content in ‘~/.editrc’ will
     turn ON 'vi' keybindings and TAB completion:

          python:bind -v
          python:bind ^I rl_complete

     Also note that different libraries may use different history file
     formats.  When switching the underlying library, existing history
     files may become unusable.

 -- Data: readline.backend

     The name of the underlying Readline library being used, either
     ‘"readline"’ or ‘"editline"’.

     Added in version 3.13.

* Menu:

* Init file::
* Line buffer::
* History file::
* History list::
* Startup hooks::
* Completion::
* Example::

   ---------- Footnotes ----------

   (1) 
https://tiswww.cwru.edu/php/chet/readline/rluserman.html#Readline-Init-File


File: python.info,  Node: Init file,  Next: Line buffer,  Up: readline — GNU readline interface

5.6.7.1 Init file
.................

The following functions relate to the init file and user configuration:

 -- Function: readline.parse_and_bind (string)

     Execute the init line provided in the 'string' argument.  This
     calls ‘rl_parse_and_bind()’ in the underlying library.

 -- Function: readline.read_init_file ([filename])

     Execute a readline initialization file.  The default filename is
     the last filename used.  This calls ‘rl_read_init_file()’ in the
     underlying library.


File: python.info,  Node: Line buffer,  Next: History file,  Prev: Init file,  Up: readline — GNU readline interface

5.6.7.2 Line buffer
...................

The following functions operate on the line buffer:

 -- Function: readline.get_line_buffer ()

     Return the current contents of the line buffer (‘rl_line_buffer’ in
     the underlying library).

 -- Function: readline.insert_text (string)

     Insert text into the line buffer at the cursor position.  This
     calls ‘rl_insert_text()’ in the underlying library, but ignores the
     return value.

 -- Function: readline.redisplay ()

     Change what’s displayed on the screen to reflect the current
     contents of the line buffer.  This calls ‘rl_redisplay()’ in the
     underlying library.


File: python.info,  Node: History file,  Next: History list,  Prev: Line buffer,  Up: readline — GNU readline interface

5.6.7.3 History file
....................

The following functions operate on a history file:

 -- Function: readline.read_history_file ([filename])

     Load a readline history file, and append it to the history list.
     The default filename is ‘~/.history’.  This calls ‘read_history()’
     in the underlying library.

 -- Function: readline.write_history_file ([filename])

     Save the history list to a readline history file, overwriting any
     existing file.  The default filename is ‘~/.history’.  This calls
     ‘write_history()’ in the underlying library.

 -- Function: readline.append_history_file (nelements[, filename])

     Append the last 'nelements' items of history to a file.  The
     default filename is ‘~/.history’.  The file must already exist.
     This calls ‘append_history()’ in the underlying library.  This
     function only exists if Python was compiled for a version of the
     library that supports it.

     Added in version 3.5.

 -- Function: readline.get_history_length ()
 -- Function: readline.set_history_length (length)

     Set or return the desired number of lines to save in the history
     file.  The *note write_history_file(): 253f. function uses this
     value to truncate the history file, by calling
     ‘history_truncate_file()’ in the underlying library.  Negative
     values imply unlimited history file size.


File: python.info,  Node: History list,  Next: Startup hooks,  Prev: History file,  Up: readline — GNU readline interface

5.6.7.4 History list
....................

The following functions operate on a global history list:

 -- Function: readline.clear_history ()

     Clear the current history.  This calls ‘clear_history()’ in the
     underlying library.  The Python function only exists if Python was
     compiled for a version of the library that supports it.

 -- Function: readline.get_current_history_length ()

     Return the number of items currently in the history.  (This is
     different from *note get_history_length(): 2540, which returns the
     maximum number of lines that will be written to a history file.)

 -- Function: readline.get_history_item (index)

     Return the current contents of history item at 'index'.  The item
     index is one-based.  This calls ‘history_get()’ in the underlying
     library.

 -- Function: readline.remove_history_item (pos)

     Remove history item specified by its position from the history.
     The position is zero-based.  This calls ‘remove_history()’ in the
     underlying library.

 -- Function: readline.replace_history_item (pos, line)

     Replace history item specified by its position with 'line'.  The
     position is zero-based.  This calls ‘replace_history_entry()’ in
     the underlying library.

 -- Function: readline.add_history (line)

     Append 'line' to the history buffer, as if it was the last line
     typed.  This calls ‘add_history()’ in the underlying library.

 -- Function: readline.set_auto_history (enabled)

     Enable or disable automatic calls to ‘add_history()’ when reading
     input via readline.  The 'enabled' argument should be a Boolean
     value that when true, enables auto history, and that when false,
     disables auto history.

     Added in version 3.6.

     'CPython implementation detail:' Auto history is enabled by
     default, and changes to this do not persist across multiple
     sessions.


File: python.info,  Node: Startup hooks,  Next: Completion,  Prev: History list,  Up: readline — GNU readline interface

5.6.7.5 Startup hooks
.....................

 -- Function: readline.set_startup_hook ([function])

     Set or remove the function invoked by the ‘rl_startup_hook’
     callback of the underlying library.  If 'function' is specified, it
     will be used as the new hook function; if omitted or ‘None’, any
     function already installed is removed.  The hook is called with no
     arguments just before readline prints the first prompt.

 -- Function: readline.set_pre_input_hook ([function])

     Set or remove the function invoked by the ‘rl_pre_input_hook’
     callback of the underlying library.  If 'function' is specified, it
     will be used as the new hook function; if omitted or ‘None’, any
     function already installed is removed.  The hook is called with no
     arguments after the first prompt has been printed and just before
     readline starts reading input characters.  This function only
     exists if Python was compiled for a version of the library that
     supports it.


File: python.info,  Node: Completion,  Next: Example,  Prev: Startup hooks,  Up: readline — GNU readline interface

5.6.7.6 Completion
..................

The following functions relate to implementing a custom word completion
function.  This is typically operated by the Tab key, and can suggest
and automatically complete a word being typed.  By default, Readline is
set up to be used by *note rlcompleter: bd. to complete Python
identifiers for the interactive interpreter.  If the ‘readline’ module
is to be used with a custom completer, a different set of word
delimiters should be set.

 -- Function: readline.set_completer ([function])

     Set or remove the completer function.  If 'function' is specified,
     it will be used as the new completer function; if omitted or
     ‘None’, any completer function already installed is removed.  The
     completer function is called as ‘function(text, state)’, for
     'state' in ‘0’, ‘1’, ‘2’, …, until it returns a non-string value.
     It should return the next possible completion starting with 'text'.

     The installed completer function is invoked by the 'entry_func'
     callback passed to ‘rl_completion_matches()’ in the underlying
     library.  The 'text' string comes from the first parameter to the
     ‘rl_attempted_completion_function’ callback of the underlying
     library.

 -- Function: readline.get_completer ()

     Get the completer function, or ‘None’ if no completer function has
     been set.

 -- Function: readline.get_completion_type ()

     Get the type of completion being attempted.  This returns the
     ‘rl_completion_type’ variable in the underlying library as an
     integer.

 -- Function: readline.get_begidx ()
 -- Function: readline.get_endidx ()

     Get the beginning or ending index of the completion scope.  These
     indexes are the 'start' and 'end' arguments passed to the
     ‘rl_attempted_completion_function’ callback of the underlying
     library.  The values may be different in the same input editing
     scenario based on the underlying C readline implementation.  Ex:
     libedit is known to behave differently than libreadline.

 -- Function: readline.set_completer_delims (string)
 -- Function: readline.get_completer_delims ()

     Set or get the word delimiters for completion.  These determine the
     start of the word to be considered for completion (the completion
     scope).  These functions access the
     ‘rl_completer_word_break_characters’ variable in the underlying
     library.

 -- Function: readline.set_completion_display_matches_hook ([function])

     Set or remove the completion display function.  If 'function' is
     specified, it will be used as the new completion display function;
     if omitted or ‘None’, any completion display function already
     installed is removed.  This sets or clears the
     ‘rl_completion_display_matches_hook’ callback in the underlying
     library.  The completion display function is called as
     ‘function(substitution, [matches], longest_match_length)’ once each
     time matches need to be displayed.


File: python.info,  Node: Example,  Prev: Completion,  Up: readline — GNU readline interface

5.6.7.7 Example
...............

The following example demonstrates how to use the ‘readline’ module’s
history reading and writing functions to automatically load and save a
history file named ‘.python_history’ from the user’s home directory.
The code below would normally be executed automatically during
interactive sessions from the user’s *note PYTHONSTARTUP: 1003. file.

     import atexit
     import os
     import readline

     histfile = os.path.join(os.path.expanduser("~"), ".python_history")
     try:
         readline.read_history_file(histfile)
         # default history len is -1 (infinite), which may grow unruly
         readline.set_history_length(1000)
     except FileNotFoundError:
         pass

     atexit.register(readline.write_history_file, histfile)

This code is actually automatically run when Python is run in *note
interactive mode: 1001. (see *note Readline configuration: 1004.).

The following example achieves the same goal but supports concurrent
interactive sessions, by only appending the new history.

     import atexit
     import os
     import readline
     histfile = os.path.join(os.path.expanduser("~"), ".python_history")

     try:
         readline.read_history_file(histfile)
         h_len = readline.get_current_history_length()
     except FileNotFoundError:
         open(histfile, 'wb').close()
         h_len = 0

     def save(prev_h_len, histfile):
         new_h_len = readline.get_current_history_length()
         readline.set_history_length(1000)
         readline.append_history_file(new_h_len - prev_h_len, histfile)
     atexit.register(save, h_len, histfile)

The following example extends the *note code.InteractiveConsole: 2552.
class to support history save/restore.

     import atexit
     import code
     import os
     import readline

     class HistoryConsole(code.InteractiveConsole):
         def __init__(self, locals=None, filename="<console>",
                      histfile=os.path.expanduser("~/.console-history")):
             code.InteractiveConsole.__init__(self, locals, filename)
             self.init_history(histfile)

         def init_history(self, histfile):
             readline.parse_and_bind("tab: complete")
             if hasattr(readline, "read_history_file"):
                 try:
                     readline.read_history_file(histfile)
                 except FileNotFoundError:
                     pass
                 atexit.register(self.save_history, histfile)

         def save_history(self, histfile):
             readline.set_history_length(1000)
             readline.write_history_file(histfile)

     Note: The new *note REPL: 16a. introduced in version 3.13 doesn’t
     support readline.  However, readline can still be used by setting
     the *note PYTHON_BASIC_REPL: 16e. environment variable.


File: python.info,  Node: rlcompleter — Completion function for GNU readline,  Prev: readline — GNU readline interface,  Up: Text Processing Services

5.6.8 ‘rlcompleter’ — Completion function for GNU readline
----------------------------------------------------------

'Source code:' Lib/rlcompleter.py(1)

__________________________________________________________________

The ‘rlcompleter’ module defines a completion function suitable to be
passed to *note set_completer(): 254b. in the *note readline: ba.
module.

When this module is imported on a Unix platform with the *note readline:
ba. module available, an instance of the *note Completer: 1ad2. class is
automatically created and its *note complete(): 2556. method is set as
the *note readline completer: 254a.  The method provides completion of
valid Python *note identifiers and keywords: 2040.

Example:

     >>> import rlcompleter
     >>> import readline
     >>> readline.parse_and_bind("tab: complete")
     >>> readline. <TAB PRESSED>
     readline.__doc__          readline.get_line_buffer(  readline.read_init_file(
     readline.__file__         readline.insert_text(      readline.set_completer(
     readline.__name__         readline.parse_and_bind(
     >>> readline.

The ‘rlcompleter’ module is designed for use with Python’s *note
interactive mode: 1001.  Unless Python is run with the *note -S: 11ec.
option, the module is automatically imported and configured (see *note
Readline configuration: 1004.).

On platforms without *note readline: ba, the *note Completer: 1ad2.
class defined by this module can still be used for custom purposes.

 -- Class: rlcompleter.Completer

     Completer objects have the following method:

      -- Method: complete (text, state)

          Return the next possible completion for 'text'.

          When called by the *note readline: ba. module, this method is
          called successively with ‘state == 0, 1, 2, ...’ until the
          method returns ‘None’.

          If called for 'text' that doesn’t include a period character
          (‘'.'’), it will complete from names currently defined in
          *note __main__: 1, *note builtins: 12. and keywords (as
          defined by the *note keyword: 84. module).

          If called for a dotted name, it will try to evaluate anything
          without obvious side-effects (functions will not be evaluated,
          but it can generate calls to *note __getattr__(): 4d6.) up to
          the last part, and find matches for the rest via the *note
          dir(): 635. function.  Any exception raised during the
          evaluation of the expression is caught, silenced and *note
          None: 678. is returned.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/rlcompleter.py


File: python.info,  Node: Binary Data Services,  Next: Data Types,  Prev: Text Processing Services,  Up: The Python Standard Library

5.7 Binary Data Services
========================

The modules described in this chapter provide some basic services
operations for manipulation of binary data.  Other operations on binary
data, specifically in relation to file formats and network protocols,
are described in the relevant sections.

Some libraries described under *note Text Processing Services: 2377.
also work with either ASCII-compatible binary formats (for example,
*note re: b9.) or all binary data (for example, *note difflib: 37.).

In addition, see the documentation for Python’s built-in binary data
types in *note Binary Sequence Types — bytes, bytearray, memoryview:
231c.

* Menu:

* struct — Interpret bytes as packed binary data::
* codecs — Codec registry and base classes::


File: python.info,  Node: struct — Interpret bytes as packed binary data,  Next: codecs — Codec registry and base classes,  Up: Binary Data Services

5.7.1 ‘struct’ — Interpret bytes as packed binary data
------------------------------------------------------

'Source code:' Lib/struct.py(1)

__________________________________________________________________

This module converts between Python values and C structs represented as
Python *note bytes: 1c2. objects.  Compact *note format strings: 255d.
describe the intended conversions to/from Python values.  The module’s
functions and objects can be used for two largely distinct applications,
data exchange with external sources (files or network connections), or
data transfer between the Python application and the C layer.

     Note: When no prefix character is given, native mode is the
     default.  It packs or unpacks data based on the platform and
     compiler on which the Python interpreter was built.  The result of
     packing a given C struct includes pad bytes which maintain proper
     alignment for the C types involved; similarly, alignment is taken
     into account when unpacking.  In contrast, when communicating data
     between external sources, the programmer is responsible for
     defining byte ordering and padding between elements.  See *note
     Byte Order, Size, and Alignment: 255e. for details.

Several *note struct: d5. functions (and methods of *note Struct: 15ad.)
take a 'buffer' argument.  This refers to objects that implement the
*note Buffer Protocol: 2e8. and provide either a readable or
read-writable buffer.  The most common types used for that purpose are
*note bytes: 1c2. and *note bytearray: 2ea, but many other types that
can be viewed as an array of bytes implement the buffer protocol, so
that they can be read/filled without additional copying from a ‘bytes’
object.

* Menu:

* Functions and Exceptions::
* Format Strings::
* Applications::
* Classes: Classes<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/struct.py


File: python.info,  Node: Functions and Exceptions,  Next: Format Strings,  Up: struct — Interpret bytes as packed binary data

5.7.1.1 Functions and Exceptions
................................

The module defines the following exception and functions:

 -- Exception: struct.error

     Exception raised on various occasions; argument is a string
     describing what is wrong.

 -- Function: struct.pack (format, v1, v2, ...)

     Return a bytes object containing the values 'v1', 'v2', … packed
     according to the format string 'format'.  The arguments must match
     the values required by the format exactly.

 -- Function: struct.pack_into (format, buffer, offset, v1, v2, ...)

     Pack the values 'v1', 'v2', … according to the format string
     'format' and write the packed bytes into the writable buffer
     'buffer' starting at position 'offset'.  Note that 'offset' is a
     required argument.

 -- Function: struct.unpack (format, buffer)

     Unpack from the buffer 'buffer' (presumably packed by ‘pack(format,
     ...)’) according to the format string 'format'.  The result is a
     tuple even if it contains exactly one item.  The buffer’s size in
     bytes must match the size required by the format, as reflected by
     *note calcsize(): 1b54.

 -- Function: struct.unpack_from (format, /, buffer, offset=0)

     Unpack from 'buffer' starting at position 'offset', according to
     the format string 'format'.  The result is a tuple even if it
     contains exactly one item.  The buffer’s size in bytes, starting at
     position 'offset', must be at least the size required by the
     format, as reflected by *note calcsize(): 1b54.

 -- Function: struct.iter_unpack (format, buffer)

     Iteratively unpack from the buffer 'buffer' according to the format
     string 'format'.  This function returns an iterator which will read
     equally sized chunks from the buffer until all its contents have
     been consumed.  The buffer’s size in bytes must be a multiple of
     the size required by the format, as reflected by *note calcsize():
     1b54.

     Each iteration yields a tuple as specified by the format string.

     Added in version 3.4.

 -- Function: struct.calcsize (format)

     Return the size of the struct (and hence of the bytes object
     produced by ‘pack(format, ...)’) corresponding to the format string
     'format'.


File: python.info,  Node: Format Strings,  Next: Applications,  Prev: Functions and Exceptions,  Up: struct — Interpret bytes as packed binary data

5.7.1.2 Format Strings
......................

Format strings describe the data layout when packing and unpacking data.
They are built up from *note format characters: 2563, which specify the
type of data being packed/unpacked.  In addition, special characters
control the *note byte order, size and alignment: 255e.  Each format
string consists of an optional prefix character which describes the
overall properties of the data and one or more format characters which
describe the actual data values and padding.

* Menu:

* Byte Order, Size, and Alignment: Byte Order Size and Alignment.
* Format Characters::
* Examples: Examples<2>.


File: python.info,  Node: Byte Order Size and Alignment,  Next: Format Characters,  Up: Format Strings

5.7.1.3 Byte Order, Size, and Alignment
.......................................

By default, C types are represented in the machine’s native format and
byte order, and properly aligned by skipping pad bytes if necessary
(according to the rules used by the C compiler).  This behavior is
chosen so that the bytes of a packed struct correspond exactly to the
memory layout of the corresponding C struct.  Whether to use native byte
ordering and padding or standard formats depends on the application.

Alternatively, the first character of the format string can be used to
indicate the byte order, size and alignment of the packed data,
according to the following table:

Character       Byte order                   Size           Alignment
                                                            
----------------------------------------------------------------------------
                                                            
‘@’             native                       native         native
                                                            
                                                            
‘=’             native                       standard       none
                                                            
                                                            
‘<’             little-endian                standard       none
                                                            
                                                            
‘>’             big-endian                   standard       none
                                                            
                                                            
‘!’             network (= big-endian)       standard       none
                                                            

If the first character is not one of these, ‘'@'’ is assumed.

     Note: The number 1023 (‘0x3ff’ in hexadecimal) has the following
     byte representations:

        * ‘03 ff’ in big-endian (‘>’)

        * ‘ff 03’ in little-endian (‘<’)

     Python example:

          >>> import struct
          >>> struct.pack('>h', 1023)
          b'\x03\xff'
          >>> struct.pack('<h', 1023)
          b'\xff\x03'

Native byte order is big-endian or little-endian, depending on the host
system.  For example, Intel x86, AMD64 (x86-64), and Apple M1 are
little-endian; IBM z and many legacy architectures are big-endian.  Use
*note sys.byteorder: 2353. to check the endianness of your system.

Native size and alignment are determined using the C compiler’s ‘sizeof’
expression.  This is always combined with native byte order.

Standard size depends only on the format character; see the table in the
*note Format Characters: 2563. section.

Note the difference between ‘'@'’ and ‘'='’: both use native byte order,
but the size and alignment of the latter is standardized.

The form ‘'!'’ represents the network byte order which is always
big-endian as defined in IETF RFC 1700(1).

There is no way to indicate non-native byte order (force byte-swapping);
use the appropriate choice of ‘'<'’ or ‘'>'’.

Notes:

  1. Padding is only automatically added between successive structure
     members.  No padding is added at the beginning or the end of the
     encoded struct.

  2. No padding is added when using non-native size and alignment, e.g.
     with ‘<’, ‘>’, ‘=’, and ‘!’.

  3. To align the end of a structure to the alignment requirement of a
     particular type, end the format with the code for that type with a
     repeat count of zero.  See *note Examples: 2565.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc1700


File: python.info,  Node: Format Characters,  Next: Examples<2>,  Prev: Byte Order Size and Alignment,  Up: Format Strings

5.7.1.4 Format Characters
.........................

Format characters have the following meaning; the conversion between C
and Python values should be obvious given their types.  The ‘Standard
size’ column refers to the size of the packed value in bytes when using
standard size; that is, when the format string starts with one of ‘'<'’,
‘'>'’, ‘'!'’ or ‘'='’.  When using native size, the size of the packed
value is platform-dependent.

Format       C Type                         Python type              Standard size        Notes
                                                                                          
-----------------------------------------------------------------------------------------------------------
                                                                                          
‘x’          pad byte                       no value                                      (7)
                                                                                          
                                                                                          
‘c’          char                           bytes of length 1        1
                                                                     
                                                                                          
‘b’          signed char                    integer                  1                    (1), (2)
                                                                                          
                                                                                          
‘B’          unsigned char                  integer                  1                    (2)
                                                                                          
                                                                                          
‘?’          _Bool                          bool                     1                    (1)
                                                                                          
                                                                                          
‘h’          short                          integer                  2                    (2)
                                                                                          
                                                                                          
‘H’          unsigned short                 integer                  2                    (2)
                                                                                          
                                                                                          
‘i’          int                            integer                  4                    (2)
                                                                                          
                                                                                          
‘I’          unsigned int                   integer                  4                    (2)
                                                                                          
                                                                                          
‘l’          long                           integer                  4                    (2)
                                                                                          
                                                                                          
‘L’          unsigned long                  integer                  4                    (2)
                                                                                          
                                                                                          
‘q’          long long                      integer                  8                    (2)
                                                                                          
                                                                                          
‘Q’          unsigned long long             integer                  8                    (2)
                                                                                          
                                                                                          
‘n’          ‘ssize_t’                      integer                                       (3)
                                                                                          
                                                                                          
‘N’          ‘size_t’                       integer                                       (3)
                                                                                          
                                                                                          
‘e’          _Float16                       float                    2                    (4), (6)
                                                                                          
                                                                                          
‘f’          float                          float                    4                    (4)
                                                                                          
                                                                                          
‘d’          double                         float                    8                    (4)
                                                                                          
                                                                                          
‘s’          char[]                         bytes                                         (9)
                                                                                          
                                                                                          
‘p’          char[]                         bytes                                         (8)
                                                                                          
                                                                                          
‘P’          void*                          integer                                       (5)
                                                                                          

Changed in version 3.3: Added support for the ‘'n'’ and ‘'N'’ formats.

Changed in version 3.6: Added support for the ‘'e'’ format.

Notes:

  1. 
     The ‘'?'’ conversion code corresponds to the _Bool type defined by
     C standards since C99.  In standard mode, it is represented by one
     byte.

  2. When attempting to pack a non-integer using any of the integer
     conversion codes, if the non-integer has a *note __index__(): 720.
     method then that method is called to convert the argument to an
     integer before packing.

     Changed in version 3.2: Added use of the *note __index__(): 720.
     method for non-integers.

  3. The ‘'n'’ and ‘'N'’ conversion codes are only available for the
     native size (selected as the default or with the ‘'@'’ byte order
     character).  For the standard size, you can use whichever of the
     other integer formats fits your application.

  4. For the ‘'f'’, ‘'d'’ and ‘'e'’ conversion codes, the packed
     representation uses the IEEE 754 binary32, binary64 or binary16
     format (for ‘'f'’, ‘'d'’ or ‘'e'’ respectively), regardless of the
     floating-point format used by the platform.

  5. The ‘'P'’ format character is only available for the native byte
     ordering (selected as the default or with the ‘'@'’ byte order
     character).  The byte order character ‘'='’ chooses to use little-
     or big-endian ordering based on the host system.  The struct module
     does not interpret this as native ordering, so the ‘'P'’ format is
     not available.

  6. The IEEE 754 binary16 “half precision” type was introduced in the
     2008 revision of the IEEE 754 standard(1).  It has a sign bit, a
     5-bit exponent and 11-bit precision (with 10 bits explicitly
     stored), and can represent numbers between approximately ‘6.1e-05’
     and ‘6.5e+04’ at full precision.  This type is not widely supported
     by C compilers: it’s available as _Float16 type, if the compiler
     supports the Annex H of the C23 standard.  On a typical machine, an
     unsigned short can be used for storage, but not for math
     operations.  See the Wikipedia page on the half-precision
     floating-point format(2) for more information.

  7. When packing, ‘'x'’ inserts one NUL byte.

  8. The ‘'p'’ format character encodes a “Pascal string”, meaning a
     short variable-length string stored in a 'fixed number of bytes',
     given by the count.  The first byte stored is the length of the
     string, or 255, whichever is smaller.  The bytes of the string
     follow.  If the string passed in to *note pack(): 12bd. is too long
     (longer than the count minus 1), only the leading ‘count-1’ bytes
     of the string are stored.  If the string is shorter than ‘count-1’,
     it is padded with null bytes so that exactly count bytes in all are
     used.  Note that for *note unpack(): 18f6, the ‘'p'’ format
     character consumes ‘count’ bytes, but that the string returned can
     never contain more than 255 bytes.

  9. For the ‘'s'’ format character, the count is interpreted as the
     length of the bytes, not a repeat count like for the other format
     characters; for example, ‘'10s'’ means a single 10-byte string
     mapping to or from a single Python byte string, while ‘'10c'’ means
     10 separate one byte character elements (e.g., ‘cccccccccc’)
     mapping to or from ten different Python byte objects.  (See *note
     Examples: 2565. for a concrete demonstration of the difference.)
     If a count is not given, it defaults to 1.  For packing, the string
     is truncated or padded with null bytes as appropriate to make it
     fit.  For unpacking, the resulting bytes object always has exactly
     the specified number of bytes.  As a special case, ‘'0s'’ means a
     single, empty string (while ‘'0c'’ means 0 characters).

A format character may be preceded by an integral repeat count.  For
example, the format string ‘'4h'’ means exactly the same as ‘'hhhh'’.

Whitespace characters between formats are ignored; a count and its
format must not contain whitespace though.

When packing a value ‘x’ using one of the integer formats (‘'b'’, ‘'B'’,
‘'h'’, ‘'H'’, ‘'i'’, ‘'I'’, ‘'l'’, ‘'L'’, ‘'q'’, ‘'Q'’), if ‘x’ is
outside the valid range for that format then *note struct.error: 136d.
is raised.

Changed in version 3.1: Previously, some of the integer formats wrapped
out-of-range values and raised *note DeprecationWarning: 1a5. instead of
*note struct.error: 136d.

For the ‘'?'’ format character, the return value is either *note True:
c2d. or *note False: b4f.  When packing, the truth value of the argument
object is used.  Either 0 or 1 in the native or standard bool
representation will be packed, and any non-zero value will be ‘True’
when unpacking.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/IEEE_754-2008_revision

   (2) 
https://en.wikipedia.org/wiki/Half-precision_floating-point_format


File: python.info,  Node: Examples<2>,  Prev: Format Characters,  Up: Format Strings

5.7.1.5 Examples
................

     Note: Native byte order examples (designated by the ‘'@'’ format
     prefix or lack of any prefix character) may not match what the
     reader’s machine produces as that depends on the platform and
     compiler.

Pack and unpack integers of three different sizes, using big endian
ordering:

     >>> from struct import *
     >>> pack(">bhl", 1, 2, 3)
     b'\x01\x00\x02\x00\x00\x00\x03'
     >>> unpack('>bhl', b'\x01\x00\x02\x00\x00\x00\x03')
     (1, 2, 3)
     >>> calcsize('>bhl')
     7

Attempt to pack an integer which is too large for the defined field:

     >>> pack(">h", 99999)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     struct.error: 'h' format requires -32768 <= number <= 32767

Demonstrate the difference between ‘'s'’ and ‘'c'’ format characters:

     >>> pack("@ccc", b'1', b'2', b'3')
     b'123'
     >>> pack("@3s", b'123')
     b'123'

Unpacked fields can be named by assigning them to variables or by
wrapping the result in a named tuple:

     >>> record = b'raymond   \x32\x12\x08\x01\x08'
     >>> name, serialnum, school, gradelevel = unpack('<10sHHb', record)

     >>> from collections import namedtuple
     >>> Student = namedtuple('Student', 'name serialnum school gradelevel')
     >>> Student._make(unpack('<10sHHb', record))
     Student(name=b'raymond   ', serialnum=4658, school=264, gradelevel=8)

The ordering of format characters may have an impact on size in native
mode since padding is implicit.  In standard mode, the user is
responsible for inserting any desired padding.  Note in the first ‘pack’
call below that three NUL bytes were added after the packed ‘'#'’ to
align the following integer on a four-byte boundary.  In this example,
the output was produced on a little endian machine:

     >>> pack('@ci', b'#', 0x12131415)
     b'#\x00\x00\x00\x15\x14\x13\x12'
     >>> pack('@ic', 0x12131415, b'#')
     b'\x15\x14\x13\x12#'
     >>> calcsize('@ci')
     8
     >>> calcsize('@ic')
     5

The following format ‘'llh0l'’ results in two pad bytes being added at
the end, assuming the platform’s longs are aligned on 4-byte boundaries:

     >>> pack('@llh0l', 1, 2, 3)
     b'\x00\x00\x00\x01\x00\x00\x00\x02\x00\x03\x00\x00'

See also
........

Module *note array: 7.

     Packed binary storage of homogeneous data.

Module *note json: 82.

     JSON encoder and decoder.

Module *note pickle: a6.

     Python object serialization.


File: python.info,  Node: Applications,  Next: Classes<3>,  Prev: Format Strings,  Up: struct — Interpret bytes as packed binary data

5.7.1.6 Applications
....................

Two main applications for the *note struct: d5. module exist, data
interchange between Python and C code within an application or another
application compiled using the same compiler (*note native formats:
256a.), and data interchange between applications using agreed upon data
layout (*note standard formats: 256b.).  Generally speaking, the format
strings constructed for these two domains are distinct.

* Menu:

* Native Formats::
* Standard Formats::


File: python.info,  Node: Native Formats,  Next: Standard Formats,  Up: Applications

5.7.1.7 Native Formats
......................

When constructing format strings which mimic native layouts, the
compiler and machine architecture determine byte ordering and padding.
In such cases, the ‘@’ format character should be used to specify native
byte ordering and data sizes.  Internal pad bytes are normally inserted
automatically.  It is possible that a zero-repeat format code will be
needed at the end of a format string to round up to the correct byte
boundary for proper alignment of consecutive chunks of data.

Consider these two simple examples (on a 64-bit, little-endian machine):

     >>> calcsize('@lhl')
     24
     >>> calcsize('@llh')
     18

Data is not padded to an 8-byte boundary at the end of the second format
string without the use of extra padding.  A zero-repeat format code
solves that problem:

     >>> calcsize('@llh0l')
     24

The ‘'x'’ format code can be used to specify the repeat, but for native
formats it is better to use a zero-repeat format like ‘'0l'’.

By default, native byte ordering and alignment is used, but it is better
to be explicit and use the ‘'@'’ prefix character.


File: python.info,  Node: Standard Formats,  Prev: Native Formats,  Up: Applications

5.7.1.8 Standard Formats
........................

When exchanging data beyond your process such as networking or storage,
be precise.  Specify the exact byte order, size, and alignment.  Do not
assume they match the native order of a particular machine.  For
example, network byte order is big-endian, while many popular CPUs are
little-endian.  By defining this explicitly, the user need not care
about the specifics of the platform their code is running on.  The first
character should typically be ‘<’ or ‘>’ (or ‘!’).  Padding is the
responsibility of the programmer.  The zero-repeat format character
won’t work.  Instead, the user must explicitly add ‘'x'’ pad bytes where
needed.  Revisiting the examples from the previous section, we have:

     >>> calcsize('<qh6xq')
     24
     >>> pack('<qh6xq', 1, 2, 3) == pack('@lhl', 1, 2, 3)
     True
     >>> calcsize('@llh')
     18
     >>> pack('@llh', 1, 2, 3) == pack('<qqh', 1, 2, 3)
     True
     >>> calcsize('<qqh6x')
     24
     >>> calcsize('@llh0l')
     24
     >>> pack('@llh0l', 1, 2, 3) == pack('<qqh6x', 1, 2, 3)
     True

The above results (executed on a 64-bit machine) aren’t guaranteed to
match when executed on different machines.  For example, the examples
below were executed on a 32-bit machine:

     >>> calcsize('<qqh6x')
     24
     >>> calcsize('@llh0l')
     12
     >>> pack('@llh0l', 1, 2, 3) == pack('<qqh6x', 1, 2, 3)
     False


File: python.info,  Node: Classes<3>,  Prev: Applications,  Up: struct — Interpret bytes as packed binary data

5.7.1.9 Classes
...............

The *note struct: d5. module also defines the following type:

 -- Class: struct.Struct (format)

     Return a new Struct object which writes and reads binary data
     according to the format string 'format'.  Creating a ‘Struct’
     object once and calling its methods is more efficient than calling
     module-level functions with the same format since the format string
     is only compiled once.

          Note: The compiled versions of the most recent format strings
          passed to the module-level functions are cached, so programs
          that use only a few format strings needn’t worry about reusing
          a single ‘Struct’ instance.

     Compiled Struct objects support the following methods and
     attributes:

      -- Method: pack (v1, v2, ...)

          Identical to the *note pack(): 12bd. function, using the
          compiled format.  (‘len(result)’ will equal *note size: 2571.)

      -- Method: pack_into (buffer, offset, v1, v2, ...)

          Identical to the *note pack_into(): 2560. function, using the
          compiled format.

      -- Method: unpack (buffer)

          Identical to the *note unpack(): 18f6. function, using the
          compiled format.  The buffer’s size in bytes must equal *note
          size: 2571.

      -- Method: unpack_from (buffer, offset=0)

          Identical to the *note unpack_from(): 2561. function, using
          the compiled format.  The buffer’s size in bytes, starting at
          position 'offset', must be at least *note size: 2571.

      -- Method: iter_unpack (buffer)

          Identical to the *note iter_unpack(): ff8. function, using the
          compiled format.  The buffer’s size in bytes must be a
          multiple of *note size: 2571.

          Added in version 3.4.

      -- Attribute: format

          The format string used to construct this Struct object.

          Changed in version 3.7: The format string type is now *note
          str: 44f. instead of *note bytes: 1c2.

      -- Attribute: size

          The calculated size of the struct (and hence of the bytes
          object produced by the *note pack(): 12bd. method)
          corresponding to *note format: 622.

     Changed in version 3.13: The 'repr()' of structs has changed.  It
     is now:

          >>> Struct('i')
          Struct('i')


File: python.info,  Node: codecs — Codec registry and base classes,  Prev: struct — Interpret bytes as packed binary data,  Up: Binary Data Services

5.7.2 ‘codecs’ — Codec registry and base classes
------------------------------------------------

'Source code:' Lib/codecs.py(1)

__________________________________________________________________

This module defines base classes for standard Python codecs (encoders
and decoders) and provides access to the internal Python codec registry,
which manages the codec and error handling lookup process.  Most
standard codecs are *note text encodings: 2333, which encode text to
bytes (and decode bytes to text), but there are also codecs provided
that encode text to text, and bytes to bytes.  Custom codecs may encode
and decode between arbitrary types, but some module features are
restricted to be used specifically with text encodings or with codecs
that encode to *note bytes: 1c2.

The module defines the following functions for encoding and decoding
with any codec:

 -- Function: codecs.encode (obj, encoding='utf-8', errors='strict')

     Encodes 'obj' using the codec registered for 'encoding'.

     'Errors' may be given to set the desired error handling scheme.
     The default error handler is ‘'strict'’ meaning that encoding
     errors raise *note ValueError: 202. (or a more codec specific
     subclass, such as *note UnicodeEncodeError: 67a.).  Refer to *note
     Codec Base Classes: 2578. for more information on codec error
     handling.

 -- Function: codecs.decode (obj, encoding='utf-8', errors='strict')

     Decodes 'obj' using the codec registered for 'encoding'.

     'Errors' may be given to set the desired error handling scheme.
     The default error handler is ‘'strict'’ meaning that decoding
     errors raise *note ValueError: 202. (or a more codec specific
     subclass, such as *note UnicodeDecodeError: a20.).  Refer to *note
     Codec Base Classes: 2578. for more information on codec error
     handling.

 -- Function: codecs.charmap_build (string)

     Return a mapping suitable for encoding with a custom single-byte
     encoding.  Given a *note str: 44f. 'string' of up to 256 characters
     representing a decoding table, returns either a compact internal
     mapping object ‘EncodingMap’ or a *note dictionary: 256. mapping
     character ordinals to byte values.  Raises a *note TypeError: 2c3.
     on invalid input.

The full details for each codec can also be looked up directly:

 -- Function: codecs.lookup (encoding)

     Looks up the codec info in the Python codec registry and returns a
     *note CodecInfo: 180b. object as defined below.

     Encodings are first looked up in the registry’s cache.  If not
     found, the list of registered search functions is scanned.  If no
     *note CodecInfo: 180b. object is found, a *note LookupError: 238a.
     is raised.  Otherwise, the ‘CodecInfo’ object is stored in the
     cache and returned to the caller.

 -- Class: codecs.CodecInfo (encode, decode, streamreader=None,
          streamwriter=None, incrementalencoder=None,
          incrementaldecoder=None, name=None)

     Codec details when looking up the codec registry.  The constructor
     arguments are stored in attributes of the same name:

      -- Attribute: name

          The name of the encoding.

      -- Attribute: encode
      -- Attribute: decode

          The stateless encoding and decoding functions.  These must be
          functions or methods which have the same interface as the
          *note encode(): 257d. and *note decode(): 257e. methods of
          Codec instances (see *note Codec Interface: 257f.).  The
          functions or methods are expected to work in a stateless mode.

      -- Attribute: incrementalencoder
      -- Attribute: incrementaldecoder

          Incremental encoder and decoder classes or factory functions.
          These have to provide the interface defined by the base
          classes *note IncrementalEncoder: 2582. and *note
          IncrementalDecoder: 2583, respectively.  Incremental codecs
          can maintain state.

      -- Attribute: streamwriter
      -- Attribute: streamreader

          Stream writer and reader classes or factory functions.  These
          have to provide the interface defined by the base classes
          *note StreamWriter: 2586. and *note StreamReader: 2587,
          respectively.  Stream codecs can maintain state.

To simplify access to the various codec components, the module provides
these additional functions which use *note lookup(): 96d. for the codec
lookup:

 -- Function: codecs.getencoder (encoding)

     Look up the codec for the given encoding and return its encoder
     function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found.

 -- Function: codecs.getdecoder (encoding)

     Look up the codec for the given encoding and return its decoder
     function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found.

 -- Function: codecs.getincrementalencoder (encoding)

     Look up the codec for the given encoding and return its incremental
     encoder class or factory function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found or the codec doesn’t support an incremental encoder.

 -- Function: codecs.getincrementaldecoder (encoding)

     Look up the codec for the given encoding and return its incremental
     decoder class or factory function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found or the codec doesn’t support an incremental decoder.

 -- Function: codecs.getreader (encoding)

     Look up the codec for the given encoding and return its *note
     StreamReader: 2587. class or factory function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found.

 -- Function: codecs.getwriter (encoding)

     Look up the codec for the given encoding and return its *note
     StreamWriter: 2586. class or factory function.

     Raises a *note LookupError: 238a. in case the encoding cannot be
     found.

Custom codecs are made available by registering a suitable codec search
function:

 -- Function: codecs.register (search_function)

     Register a codec search function.  Search functions are expected to
     take one argument, being the encoding name in all lower case
     letters with hyphens and spaces converted to underscores, and
     return a *note CodecInfo: 180b. object.  In case a search function
     cannot find a given encoding, it should return ‘None’.

     Changed in version 3.9: Hyphens and spaces are converted to
     underscore.

 -- Function: codecs.unregister (search_function)

     Unregister a codec search function and clear the registry’s cache.
     If the search function is not registered, do nothing.

     Added in version 3.10.

While the builtin *note open(): 51f. and the associated *note io: 7f.
module are the recommended approach for working with encoded text files,
this module provides additional utility functions and classes that allow
the use of a wider range of codecs when working with binary files:

 -- Function: codecs.open (filename, mode='r', encoding=None,
          errors='strict', buffering=-1)

     Open an encoded file using the given 'mode' and return an instance
     of *note StreamReaderWriter: 258f, providing transparent
     encoding/decoding.  The default file mode is ‘'r'’, meaning to open
     the file in read mode.

          Note: If 'encoding' is not ‘None’, then the underlying encoded
          files are always opened in binary mode.  No automatic
          conversion of ‘'\n'’ is done on reading and writing.  The
          'mode' argument may be any binary mode acceptable to the
          built-in ‘open()’ function; the ‘'b'’ is automatically added.

     'encoding' specifies the encoding which is to be used for the file.
     Any encoding that encodes to and decodes from bytes is allowed, and
     the data types supported by the file methods depend on the codec
     used.

     'errors' may be given to define the error handling.  It defaults to
     ‘'strict'’ which causes a *note ValueError: 202. to be raised in
     case an encoding error occurs.

     'buffering' has the same meaning as for the built-in ‘open()’
     function.  It defaults to -1 which means that the default buffer
     size will be used.

     Changed in version 3.11: The ‘'U'’ mode has been removed.

 -- Function: codecs.EncodedFile (file, data_encoding,
          file_encoding=None, errors='strict')

     Return a *note StreamRecoder: 1b81. instance, a wrapped version of
     'file' which provides transparent transcoding.  The original file
     is closed when the wrapped version is closed.

     Data written to the wrapped file is decoded according to the given
     'data_encoding' and then written to the original file as bytes
     using 'file_encoding'.  Bytes read from the original file are
     decoded according to 'file_encoding', and the result is encoded
     using 'data_encoding'.

     If 'file_encoding' is not given, it defaults to 'data_encoding'.

     'errors' may be given to define the error handling.  It defaults to
     ‘'strict'’, which causes *note ValueError: 202. to be raised in
     case an encoding error occurs.

 -- Function: codecs.iterencode (iterator, encoding, errors='strict',
          **kwargs)

     Uses an incremental encoder to iteratively encode the input
     provided by 'iterator'.  'iterator' must yield *note str: 44f.
     objects.  This function is a *note generator: 109f.  The 'errors'
     argument (as well as any other keyword argument) is passed through
     to the incremental encoder.

     This function requires that the codec accept text *note str: 44f.
     objects to encode.  Therefore it does not support bytes-to-bytes
     encoders such as ‘base64_codec’.

 -- Function: codecs.iterdecode (iterator, encoding, errors='strict',
          **kwargs)

     Uses an incremental decoder to iteratively decode the input
     provided by 'iterator'.  'iterator' must yield *note bytes: 1c2.
     objects.  This function is a *note generator: 109f.  The 'errors'
     argument (as well as any other keyword argument) is passed through
     to the incremental decoder.

     This function requires that the codec accept *note bytes: 1c2.
     objects to decode.  Therefore it does not support text-to-text
     encoders such as ‘rot_13’, although ‘rot_13’ may be used
     equivalently with *note iterencode(): 2591.

 -- Function: codecs.readbuffer_encode (buffer, errors=None, /)

     Return a *note tuple: 373. containing the raw bytes of 'buffer', a
     *note buffer-compatible object: 2e8. or *note str: 44f. (encoded to
     UTF-8 before processing), and their length in bytes.

     The 'errors' argument is ignored.

          >>> codecs.readbuffer_encode(b"Zito")
          (b'Zito', 4)

The module also provides the following constants which are useful for
reading and writing to platform dependent files:

 -- Data: codecs.BOM
 -- Data: codecs.BOM_BE
 -- Data: codecs.BOM_LE
 -- Data: codecs.BOM_UTF8
 -- Data: codecs.BOM_UTF16
 -- Data: codecs.BOM_UTF16_BE
 -- Data: codecs.BOM_UTF16_LE
 -- Data: codecs.BOM_UTF32
 -- Data: codecs.BOM_UTF32_BE
 -- Data: codecs.BOM_UTF32_LE

     These constants define various byte sequences, being Unicode byte
     order marks (BOMs) for several encodings.  They are used in UTF-16
     and UTF-32 data streams to indicate the byte order used, and in
     UTF-8 as a Unicode signature.  *note BOM_UTF16: 2598. is either
     *note BOM_UTF16_BE: 2599. or *note BOM_UTF16_LE: 259a. depending on
     the platform’s native byte order, *note BOM: 2594. is an alias for
     ‘BOM_UTF16’, *note BOM_LE: 2596. for ‘BOM_UTF16_LE’ and *note
     BOM_BE: 2595. for ‘BOM_UTF16_BE’.  The others represent the BOM in
     UTF-8 and UTF-32 encodings.

* Menu:

* Codec Base Classes::
* Encodings and Unicode::
* Standard Encodings::
* Python Specific Encodings::
* encodings — Encodings package::
* encodings.idna — Internationalized Domain Names in Applications: encodings idna — Internationalized Domain Names in Applications.
* encodings.mbcs — Windows ANSI codepage: encodings mbcs — Windows ANSI codepage.
* encodings.utf_8_sig — UTF-8 codec with BOM signature: encodings utf_8_sig — UTF-8 codec with BOM signature.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/codecs.py


File: python.info,  Node: Codec Base Classes,  Next: Encodings and Unicode,  Up: codecs — Codec registry and base classes

5.7.2.1 Codec Base Classes
..........................

The ‘codecs’ module defines a set of base classes which define the
interfaces for working with codec objects, and can also be used as the
basis for custom codec implementations.

Each codec has to define four interfaces to make it usable as codec in
Python: stateless encoder, stateless decoder, stream reader and stream
writer.  The stream reader and writers typically reuse the stateless
encoder/decoder to implement the file protocols.  Codec authors also
need to define how the codec will handle encoding and decoding errors.
* Menu:

* Error Handlers::
* Stateless Encoding and Decoding::
* Incremental Encoding and Decoding::
* Stream Encoding and Decoding::


File: python.info,  Node: Error Handlers,  Next: Stateless Encoding and Decoding,  Up: Codec Base Classes

5.7.2.2 Error Handlers
......................

To simplify and standardize error handling, codecs may implement
different error handling schemes by accepting the 'errors' string
argument:

     >>> 'German ß, ♬'.encode(encoding='ascii', errors='backslashreplace')
     b'German \\xdf, \\u266c'
     >>> 'German ß, ♬'.encode(encoding='ascii', errors='xmlcharrefreplace')
     b'German &#223;, &#9836;'

The following error handlers can be used with all Python *note Standard
Encodings: de7. codecs:

Value                         Meaning
                              
----------------------------------------------------------------------------------
                              
‘'strict'’                    Raise *note UnicodeError: 12eb. (or a subclass),
                              this is the default.  Implemented in
                              *note strict_errors(): 25a1.
                              
                              
‘'ignore'’                    Ignore the malformed data and continue without
                              further notice.  Implemented in
                              *note ignore_errors(): 25a2.
                              
                              
‘'replace'’                   Replace with a replacement marker.  On encoding,
                              use ‘?’ (ASCII character).  On decoding, use ‘�’
                              (U+FFFD, the official REPLACEMENT CHARACTER).
                              Implemented in *note replace_errors(): 25a3.
                              
                              
‘'backslashreplace'’          Replace with backslashed escape sequences.  On
                              encoding, use hexadecimal form of Unicode code
                              point with formats ‘\xHH’ ‘\uXXXX’ ‘\UXXXXXXXX’.
                              On decoding, use hexadecimal form of byte value
                              with format ‘\xHH’.  Implemented in
                              *note backslashreplace_errors(): 25a4.
                              
                              
‘'surrogateescape'’           On decoding, replace byte with individual
                              surrogate code ranging from ‘U+DC80’ to ‘U+DCFF’.
                              This code will then be turned back into the same
                              byte when the ‘'surrogateescape'’ error handler
                              is used when encoding the data.  (See PEP 383(1)
                              for more.)
                              

The following error handlers are only applicable to encoding (within
*note text encodings: 2333.):

Value                         Meaning
                              
----------------------------------------------------------------------------------
                              
‘'xmlcharrefreplace'’         Replace with XML/HTML numeric character
                              reference, which is a decimal form of Unicode
                              code point with format ‘&#NUM;’.  Implemented in
                              *note xmlcharrefreplace_errors(): 25a5.
                              
                              
‘'namereplace'’               Replace with ‘\N{...}’ escape sequences, what
                              appears in the braces is the Name property from
                              Unicode Character Database.  Implemented in
                              *note namereplace_errors(): 25a6.
                              

In addition, the following error handler is specific to the given
codecs:

Value                   Codecs                       Meaning
                                                     
-----------------------------------------------------------------------------------------------------
                                                     
‘'surrogatepass'’       utf-8, utf-16, utf-32,       Allow encoding and decoding surrogate code
                        utf-16-be, utf-16-le,        point (‘U+D800’ - ‘U+DFFF’) as normal code
                        utf-32-be, utf-32-le         point.  Otherwise these codecs treat the
                                                     presence of surrogate code point in
                                                     *note str: 44f. as an error.
                                                     

Added in version 3.1: The ‘'surrogateescape'’ and ‘'surrogatepass'’
error handlers.

Changed in version 3.4: The ‘'surrogatepass'’ error handler now works
with utf-16* and utf-32* codecs.

Added in version 3.5: The ‘'namereplace'’ error handler.

Changed in version 3.5: The ‘'backslashreplace'’ error handler now works
with decoding and translating.

The set of allowed values can be extended by registering a new named
error handler:

 -- Function: codecs.register_error (name, error_handler)

     Register the error handling function 'error_handler' under the name
     'name'.  The 'error_handler' argument will be called during
     encoding and decoding in case of an error, when 'name' is specified
     as the errors parameter.

     For encoding, 'error_handler' will be called with a *note
     UnicodeEncodeError: 67a. instance, which contains information about
     the location of the error.  The error handler must either raise
     this or a different exception, or return a tuple with a replacement
     for the unencodable part of the input and a position where encoding
     should continue.  The replacement may be either *note str: 44f. or
     *note bytes: 1c2.  If the replacement is bytes, the encoder will
     simply copy them into the output buffer.  If the replacement is a
     string, the encoder will encode the replacement.  Encoding
     continues on original input at the specified position.  Negative
     position values will be treated as being relative to the end of the
     input string.  If the resulting position is out of bound an *note
     IndexError: 1585. will be raised.

     Decoding and translating works similarly, except *note
     UnicodeDecodeError: a20. or *note UnicodeTranslateError: 2456. will
     be passed to the handler and that the replacement from the error
     handler will be put into the output directly.

Previously registered error handlers (including the standard error
handlers) can be looked up by name:

 -- Function: codecs.lookup_error (name)

     Return the error handler previously registered under the name
     'name'.

     Raises a *note LookupError: 238a. in case the handler cannot be
     found.

The following standard error handlers are also made available as module
level functions:

 -- Function: codecs.strict_errors (exception)

     Implements the ‘'strict'’ error handling.

     Each encoding or decoding error raises a *note UnicodeError: 12eb.

 -- Function: codecs.ignore_errors (exception)

     Implements the ‘'ignore'’ error handling.

     Malformed data is ignored; encoding or decoding is continued
     without further notice.

 -- Function: codecs.replace_errors (exception)

     Implements the ‘'replace'’ error handling.

     Substitutes ‘?’ (ASCII character) for encoding errors or ‘�’
     (U+FFFD, the official REPLACEMENT CHARACTER) for decoding errors.

 -- Function: codecs.backslashreplace_errors (exception)

     Implements the ‘'backslashreplace'’ error handling.

     Malformed data is replaced by a backslashed escape sequence.  On
     encoding, use the hexadecimal form of Unicode code point with
     formats ‘\xHH’ ‘\uXXXX’ ‘\UXXXXXXXX’.  On decoding, use the
     hexadecimal form of byte value with format ‘\xHH’.

     Changed in version 3.5: Works with decoding and translating.

 -- Function: codecs.xmlcharrefreplace_errors (exception)

     Implements the ‘'xmlcharrefreplace'’ error handling (for encoding
     within *note text encoding: 2333. only).

     The unencodable character is replaced by an appropriate XML/HTML
     numeric character reference, which is a decimal form of Unicode
     code point with format ‘&#NUM;’ .

 -- Function: codecs.namereplace_errors (exception)

     Implements the ‘'namereplace'’ error handling (for encoding within
     *note text encoding: 2333. only).

     The unencodable character is replaced by a ‘\N{...}’ escape
     sequence.  The set of characters that appear in the braces is the
     Name property from Unicode Character Database.  For example, the
     German lowercase letter ‘'ß'’ will be converted to byte sequence
     ‘\N{LATIN SMALL LETTER SHARP S}’ .

     Added in version 3.5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0383/


File: python.info,  Node: Stateless Encoding and Decoding,  Next: Incremental Encoding and Decoding,  Prev: Error Handlers,  Up: Codec Base Classes

5.7.2.3 Stateless Encoding and Decoding
.......................................

The base *note Codec: 25a8. class defines these methods which also
define the function interfaces of the stateless encoder and decoder:

 -- Class: codecs.Codec

      -- Method: encode (input, errors='strict')

          Encodes the object 'input' and returns a tuple (output object,
          length consumed).  For instance, *note text encoding: 2333.
          converts a string object to a bytes object using a particular
          character set encoding (e.g., ‘cp1252’ or ‘iso-8859-1’).

          The 'errors' argument defines the error handling to apply.  It
          defaults to ‘'strict'’ handling.

          The method may not store state in the ‘Codec’ instance.  Use
          *note StreamWriter: 2586. for codecs which have to keep state
          in order to make encoding efficient.

          The encoder must be able to handle zero length input and
          return an empty object of the output object type in this
          situation.

      -- Method: decode (input, errors='strict')

          Decodes the object 'input' and returns a tuple (output object,
          length consumed).  For instance, for a *note text encoding:
          2333, decoding converts a bytes object encoded using a
          particular character set encoding to a string object.

          For text encodings and bytes-to-bytes codecs, 'input' must be
          a bytes object or one which provides the read-only buffer
          interface – for example, buffer objects and memory mapped
          files.

          The 'errors' argument defines the error handling to apply.  It
          defaults to ‘'strict'’ handling.

          The method may not store state in the ‘Codec’ instance.  Use
          *note StreamReader: 2587. for codecs which have to keep state
          in order to make decoding efficient.

          The decoder must be able to handle zero length input and
          return an empty object of the output object type in this
          situation.


File: python.info,  Node: Incremental Encoding and Decoding,  Next: Stream Encoding and Decoding,  Prev: Stateless Encoding and Decoding,  Up: Codec Base Classes

5.7.2.4 Incremental Encoding and Decoding
.........................................

The *note IncrementalEncoder: 2582. and *note IncrementalDecoder: 2583.
classes provide the basic interface for incremental encoding and
decoding.  Encoding/decoding the input isn’t done with one call to the
stateless encoder/decoder function, but with multiple calls to the *note
encode(): 25aa./*note decode(): 25ab. method of the incremental
encoder/decoder.  The incremental encoder/decoder keeps track of the
encoding/decoding process during method calls.

The joined output of calls to the *note encode(): 25aa./*note decode():
25ab. method is the same as if all the single inputs were joined into
one, and this input was encoded/decoded with the stateless
encoder/decoder.

* Menu:

* IncrementalEncoder Objects::
* IncrementalDecoder Objects::


File: python.info,  Node: IncrementalEncoder Objects,  Next: IncrementalDecoder Objects,  Up: Incremental Encoding and Decoding

5.7.2.5 IncrementalEncoder Objects
..................................

The *note IncrementalEncoder: 2582. class is used for encoding an input
in multiple steps.  It defines the following methods which every
incremental encoder must define in order to be compatible with the
Python codec registry.

 -- Class: codecs.IncrementalEncoder (errors='strict')

     Constructor for an ‘IncrementalEncoder’ instance.

     All incremental encoders must provide this constructor interface.
     They are free to add additional keyword arguments, but only the
     ones defined here are used by the Python codec registry.

     The ‘IncrementalEncoder’ may implement different error handling
     schemes by providing the 'errors' keyword argument.  See *note
     Error Handlers: 1915. for possible values.

     The 'errors' argument will be assigned to an attribute of the same
     name.  Assigning to this attribute makes it possible to switch
     between different error handling strategies during the lifetime of
     the ‘IncrementalEncoder’ object.

      -- Method: encode (object, final=False)

          Encodes 'object' (taking the current state of the encoder into
          account) and returns the resulting encoded object.  If this is
          the last call to ‘encode()’ 'final' must be true (the default
          is false).

      -- Method: reset ()

          Reset the encoder to the initial state.  The output is
          discarded: call ‘.encode(object, final=True)’, passing an
          empty byte or text string if necessary, to reset the encoder
          and to get the output.

      -- Method: getstate ()

          Return the current state of the encoder which must be an
          integer.  The implementation should make sure that ‘0’ is the
          most common state.  (States that are more complicated than
          integers can be converted into an integer by
          marshaling/pickling the state and encoding the bytes of the
          resulting string into an integer.)

      -- Method: setstate (state)

          Set the state of the encoder to 'state'.  'state' must be an
          encoder state returned by *note getstate(): 25af.


File: python.info,  Node: IncrementalDecoder Objects,  Prev: IncrementalEncoder Objects,  Up: Incremental Encoding and Decoding

5.7.2.6 IncrementalDecoder Objects
..................................

The *note IncrementalDecoder: 2583. class is used for decoding an input
in multiple steps.  It defines the following methods which every
incremental decoder must define in order to be compatible with the
Python codec registry.

 -- Class: codecs.IncrementalDecoder (errors='strict')

     Constructor for an ‘IncrementalDecoder’ instance.

     All incremental decoders must provide this constructor interface.
     They are free to add additional keyword arguments, but only the
     ones defined here are used by the Python codec registry.

     The ‘IncrementalDecoder’ may implement different error handling
     schemes by providing the 'errors' keyword argument.  See *note
     Error Handlers: 1915. for possible values.

     The 'errors' argument will be assigned to an attribute of the same
     name.  Assigning to this attribute makes it possible to switch
     between different error handling strategies during the lifetime of
     the ‘IncrementalDecoder’ object.

      -- Method: decode (object, final=False)

          Decodes 'object' (taking the current state of the decoder into
          account) and returns the resulting decoded object.  If this is
          the last call to ‘decode()’ 'final' must be true (the default
          is false).  If 'final' is true the decoder must decode the
          input completely and must flush all buffers.  If this isn’t
          possible (e.g.  because of incomplete byte sequences at the
          end of the input) it must initiate error handling just like in
          the stateless case (which might raise an exception).

      -- Method: reset ()

          Reset the decoder to the initial state.

      -- Method: getstate ()

          Return the current state of the decoder.  This must be a tuple
          with two items, the first must be the buffer containing the
          still undecoded input.  The second must be an integer and can
          be additional state info.  (The implementation should make
          sure that ‘0’ is the most common additional state info.)  If
          this additional state info is ‘0’ it must be possible to set
          the decoder to the state which has no input buffered and ‘0’
          as the additional state info, so that feeding the previously
          buffered input to the decoder returns it to the previous state
          without producing any output.  (Additional state info that is
          more complicated than integers can be converted into an
          integer by marshaling/pickling the info and encoding the bytes
          of the resulting string into an integer.)

      -- Method: setstate (state)

          Set the state of the decoder to 'state'.  'state' must be a
          decoder state returned by *note getstate(): 25b4.


File: python.info,  Node: Stream Encoding and Decoding,  Prev: Incremental Encoding and Decoding,  Up: Codec Base Classes

5.7.2.7 Stream Encoding and Decoding
....................................

The *note StreamWriter: 2586. and *note StreamReader: 2587. classes
provide generic working interfaces which can be used to implement new
encoding submodules very easily.  See ‘encodings.utf_8’ for an example
of how this is done.

* Menu:

* StreamWriter Objects::
* StreamReader Objects::
* StreamReaderWriter Objects::
* StreamRecoder Objects::


File: python.info,  Node: StreamWriter Objects,  Next: StreamReader Objects,  Up: Stream Encoding and Decoding

5.7.2.8 StreamWriter Objects
............................

The *note StreamWriter: 2586. class is a subclass of *note Codec: 25a8.
and defines the following methods which every stream writer must define
in order to be compatible with the Python codec registry.

 -- Class: codecs.StreamWriter (stream, errors='strict')

     Constructor for a ‘StreamWriter’ instance.

     All stream writers must provide this constructor interface.  They
     are free to add additional keyword arguments, but only the ones
     defined here are used by the Python codec registry.

     The 'stream' argument must be a file-like object open for writing
     text or binary data, as appropriate for the specific codec.

     The ‘StreamWriter’ may implement different error handling schemes
     by providing the 'errors' keyword argument.  See *note Error
     Handlers: 1915. for the standard error handlers the underlying
     stream codec may support.

     The 'errors' argument will be assigned to an attribute of the same
     name.  Assigning to this attribute makes it possible to switch
     between different error handling strategies during the lifetime of
     the ‘StreamWriter’ object.

      -- Method: write (object)

          Writes the object’s contents encoded to the stream.

      -- Method: writelines (list)

          Writes the concatenated iterable of strings to the stream
          (possibly by reusing the *note write(): 25b9. method).
          Infinite or very large iterables are not supported.  The
          standard bytes-to-bytes codecs do not support this method.

      -- Method: reset ()

          Resets the codec buffers used for keeping internal state.

          Calling this method should ensure that the data on the output
          is put into a clean state that allows appending of new fresh
          data without having to rescan the whole stream to recover
          state.

In addition to the above methods, the *note StreamWriter: 2586. must
also inherit all other methods and attributes from the underlying
stream.


File: python.info,  Node: StreamReader Objects,  Next: StreamReaderWriter Objects,  Prev: StreamWriter Objects,  Up: Stream Encoding and Decoding

5.7.2.9 StreamReader Objects
............................

The *note StreamReader: 2587. class is a subclass of *note Codec: 25a8.
and defines the following methods which every stream reader must define
in order to be compatible with the Python codec registry.

 -- Class: codecs.StreamReader (stream, errors='strict')

     Constructor for a ‘StreamReader’ instance.

     All stream readers must provide this constructor interface.  They
     are free to add additional keyword arguments, but only the ones
     defined here are used by the Python codec registry.

     The 'stream' argument must be a file-like object open for reading
     text or binary data, as appropriate for the specific codec.

     The ‘StreamReader’ may implement different error handling schemes
     by providing the 'errors' keyword argument.  See *note Error
     Handlers: 1915. for the standard error handlers the underlying
     stream codec may support.

     The 'errors' argument will be assigned to an attribute of the same
     name.  Assigning to this attribute makes it possible to switch
     between different error handling strategies during the lifetime of
     the ‘StreamReader’ object.

     The set of allowed values for the 'errors' argument can be extended
     with *note register_error(): 14ea.

      -- Method: read (size=-1, chars=-1, firstline=False)

          Decodes data from the stream and returns the resulting object.

          The 'chars' argument indicates the number of decoded code
          points or bytes to return.  The *note read(): 25be. method
          will never return more data than requested, but it might
          return less, if there is not enough available.

          The 'size' argument indicates the approximate maximum number
          of encoded bytes or code points to read for decoding.  The
          decoder can modify this setting as appropriate.  The default
          value -1 indicates to read and decode as much as possible.
          This parameter is intended to prevent having to decode huge
          files in one step.

          The 'firstline' flag indicates that it would be sufficient to
          only return the first line, if there are decoding errors on
          later lines.

          The method should use a greedy read strategy meaning that it
          should read as much data as is allowed within the definition
          of the encoding and the given size, e.g.  if optional encoding
          endings or state markers are available on the stream, these
          should be read too.

      -- Method: readline (size=None, keepends=True)

          Read one line from the input stream and return the decoded
          data.

          'size', if given, is passed as size argument to the stream’s
          *note read(): 25be. method.

          If 'keepends' is false line-endings will be stripped from the
          lines returned.

      -- Method: readlines (sizehint=None, keepends=True)

          Read all lines available on the input stream and return them
          as a list of lines.

          Line-endings are implemented using the codec’s *note decode():
          f39. method and are included in the list entries if 'keepends'
          is true.

          'sizehint', if given, is passed as the 'size' argument to the
          stream’s *note read(): 25be. method.

      -- Method: reset ()

          Resets the codec buffers used for keeping internal state.

          Note that no stream repositioning should take place.  This
          method is primarily intended to be able to recover from
          decoding errors.

In addition to the above methods, the *note StreamReader: 2587. must
also inherit all other methods and attributes from the underlying
stream.


File: python.info,  Node: StreamReaderWriter Objects,  Next: StreamRecoder Objects,  Prev: StreamReader Objects,  Up: Stream Encoding and Decoding

5.7.2.10 StreamReaderWriter Objects
...................................

The *note StreamReaderWriter: 258f. is a convenience class that allows
wrapping streams which work in both read and write modes.

The design is such that one can use the factory functions returned by
the *note lookup(): 96d. function to construct the instance.

 -- Class: codecs.StreamReaderWriter (stream, Reader, Writer,
          errors='strict')

     Creates a ‘StreamReaderWriter’ instance.  'stream' must be a
     file-like object.  'Reader' and 'Writer' must be factory functions
     or classes providing the *note StreamReader: 2587. and *note
     StreamWriter: 2586. interface resp.  Error handling is done in the
     same way as defined for the stream readers and writers.

*note StreamReaderWriter: 258f. instances define the combined interfaces
of *note StreamReader: 2587. and *note StreamWriter: 2586. classes.
They inherit all other methods and attributes from the underlying
stream.


File: python.info,  Node: StreamRecoder Objects,  Prev: StreamReaderWriter Objects,  Up: Stream Encoding and Decoding

5.7.2.11 StreamRecoder Objects
..............................

The *note StreamRecoder: 1b81. translates data from one encoding to
another, which is sometimes useful when dealing with different encoding
environments.

The design is such that one can use the factory functions returned by
the *note lookup(): 96d. function to construct the instance.

 -- Class: codecs.StreamRecoder (stream, encode, decode, Reader, Writer,
          errors='strict')

     Creates a ‘StreamRecoder’ instance which implements a two-way
     conversion: 'encode' and 'decode' work on the frontend — the data
     visible to code calling *note read(): 25be. and *note write():
     25b9, while 'Reader' and 'Writer' work on the backend — the data in
     'stream'.

     You can use these objects to do transparent transcodings, e.g.,
     from Latin-1 to UTF-8 and back.

     The 'stream' argument must be a file-like object.

     The 'encode' and 'decode' arguments must adhere to the *note Codec:
     25a8. interface.  'Reader' and 'Writer' must be factory functions
     or classes providing objects of the *note StreamReader: 2587. and
     *note StreamWriter: 2586. interface respectively.

     Error handling is done in the same way as defined for the stream
     readers and writers.

*note StreamRecoder: 1b81. instances define the combined interfaces of
*note StreamReader: 2587. and *note StreamWriter: 2586. classes.  They
inherit all other methods and attributes from the underlying stream.


File: python.info,  Node: Encodings and Unicode,  Next: Standard Encodings,  Prev: Codec Base Classes,  Up: codecs — Codec registry and base classes

5.7.2.12 Encodings and Unicode
..............................

Strings are stored internally as sequences of code points in range
‘U+0000’–‘U+10FFFF’.  (See PEP 393(1) for more details about the
implementation.)  Once a string object is used outside of CPU and
memory, endianness and how these arrays are stored as bytes become an
issue.  As with other codecs, serialising a string into a sequence of
bytes is known as 'encoding', and recreating the string from the
sequence of bytes is known as 'decoding'.  There are a variety of
different text serialisation codecs, which are collectivity referred to
as *note text encodings: 2333.

The simplest text encoding (called ‘'latin-1'’ or ‘'iso-8859-1'’) maps
the code points 0–255 to the bytes ‘0x0’–‘0xff’, which means that a
string object that contains code points above ‘U+00FF’ can’t be encoded
with this codec.  Doing so will raise a *note UnicodeEncodeError: 67a.
that looks like the following (although the details of the error message
may differ): ‘UnicodeEncodeError: 'latin-1' codec can't encode character
'\u1234' in position 3: ordinal not in range(256)’.

There’s another group of encodings (the so called charmap encodings)
that choose a different subset of all Unicode code points and how these
code points are mapped to the bytes ‘0x0’–‘0xff’.  To see how this is
done simply open e.g.  ‘encodings/cp1252.py’ (which is an encoding that
is used primarily on Windows).  There’s a string constant with 256
characters that shows you which character is mapped to which byte value.

All of these encodings can only encode 256 of the 1114112 code points
defined in Unicode.  A simple and straightforward way that can store
each Unicode code point, is to store each code point as four consecutive
bytes.  There are two possibilities: store the bytes in big endian or in
little endian order.  These two encodings are called ‘UTF-32-BE’ and
‘UTF-32-LE’ respectively.  Their disadvantage is that if, for example,
you use ‘UTF-32-BE’ on a little endian machine you will always have to
swap bytes on encoding and decoding.  Python’s ‘UTF-16’ and ‘UTF-32’
codecs avoid this problem by using the platform’s native byte order when
no BOM is present.  Python follows prevailing platform practice, so
native-endian data round-trips without redundant byte swapping, even
though the Unicode Standard defaults to big-endian when the byte order
is unspecified.  When these bytes are read by a CPU with a different
endianness, the bytes have to be swapped.  To be able to detect the
endianness of a ‘UTF-16’ or ‘UTF-32’ byte sequence, a BOM (“Byte Order
Mark”) is used.  This is the Unicode character ‘U+FEFF’.  This character
can be prepended to every ‘UTF-16’ or ‘UTF-32’ byte sequence.  The byte
swapped version of this character (‘0xFFFE’) is an illegal character
that may not appear in a Unicode text.  When the first character of a
‘UTF-16’ or ‘UTF-32’ byte sequence is ‘U+FFFE’, the bytes have to be
swapped on decoding.

Unfortunately the character ‘U+FEFF’ had a second purpose as a ‘ZERO
WIDTH NO-BREAK SPACE’: a character that has no width and doesn’t allow a
word to be split.  It can e.g.  be used to give hints to a ligature
algorithm.  With Unicode 4.0 using ‘U+FEFF’ as a ‘ZERO WIDTH NO-BREAK
SPACE’ has been deprecated (with ‘U+2060’ (‘WORD JOINER’) assuming this
role).  Nevertheless Unicode software still must be able to handle
‘U+FEFF’ in both roles: as a BOM it’s a device to determine the storage
layout of the encoded bytes, and vanishes once the byte sequence has
been decoded into a string; as a ‘ZERO WIDTH NO-BREAK SPACE’ it’s a
normal character that will be decoded like any other.

There’s another encoding that is able to encode the full range of
Unicode characters: UTF-8.  UTF-8 is an 8-bit encoding, which means
there are no issues with byte order in UTF-8.  Each byte in a UTF-8 byte
sequence consists of two parts: marker bits (the most significant bits)
and payload bits.  The marker bits are a sequence of zero to four ‘1’
bits followed by a ‘0’ bit.  Unicode characters are encoded like this
(with x being payload bits, which when concatenated give the Unicode
character):

Range                                   Encoding
                                        
-------------------------------------------------------------------------------------------
                                        
‘U-00000000’ … ‘U-0000007F’             0xxxxxxx
                                        
                                        
‘U-00000080’ … ‘U-000007FF’             110xxxxx 10xxxxxx
                                        
                                        
‘U-00000800’ … ‘U-0000FFFF’             1110xxxx 10xxxxxx 10xxxxxx
                                        
                                        
‘U-00010000’ … ‘U-0010FFFF’             11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
                                        

The least significant bit of the Unicode character is the rightmost x
bit.

As UTF-8 is an 8-bit encoding no BOM is required and any ‘U+FEFF’
character in the decoded string (even if it’s the first character) is
treated as a ‘ZERO WIDTH NO-BREAK SPACE’.

Without external information it’s impossible to reliably determine which
encoding was used for encoding a string.  Each charmap encoding can
decode any random byte sequence.  However that’s not possible with
UTF-8, as UTF-8 byte sequences have a structure that doesn’t allow
arbitrary byte sequences.  To increase the reliability with which a
UTF-8 encoding can be detected, Microsoft invented a variant of UTF-8
(that Python calls ‘"utf-8-sig"’) for its Notepad program: Before any of
the Unicode characters is written to the file, a UTF-8 encoded BOM
(which looks like this as a byte sequence: ‘0xef’, ‘0xbb’, ‘0xbf’) is
written.  As it’s rather improbable that any charmap encoded file starts
with these byte values (which would e.g.  map to

          LATIN SMALL LETTER I WITH DIAERESIS
          RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
          INVERTED QUESTION MARK

in iso-8859-1), this increases the probability that a ‘utf-8-sig’
encoding can be correctly guessed from the byte sequence.  So here the
BOM is not used to be able to determine the byte order used for
generating the byte sequence, but as a signature that helps in guessing
the encoding.  On encoding the utf-8-sig codec will write ‘0xef’,
‘0xbb’, ‘0xbf’ as the first three bytes to the file.  On decoding
‘utf-8-sig’ will skip those three bytes if they appear as the first
three bytes in the file.  In UTF-8, the use of the BOM is discouraged
and should generally be avoided.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/


File: python.info,  Node: Standard Encodings,  Next: Python Specific Encodings,  Prev: Encodings and Unicode,  Up: codecs — Codec registry and base classes

5.7.2.13 Standard Encodings
...........................

Python comes with a number of codecs built-in, either implemented as C
functions or with dictionaries as mapping tables.  The following table
lists the codecs by name, together with a few common aliases, and the
languages for which the encoding is likely used.  Neither the list of
aliases nor the list of languages is meant to be exhaustive.  Notice
that spelling alternatives that only differ in case or use a hyphen
instead of an underscore are also valid aliases because they are
equivalent when normalized by *note normalize_encoding(): 801.  For
example, ‘'utf-8'’ is a valid alias for the ‘'utf_8'’ codec.

     Note: The below table lists the most common aliases, for a complete
     list refer to the source aliases.py(1) file.

'CPython implementation detail:' Some common encodings can bypass the
codecs lookup machinery to improve performance.  These optimization
opportunities are only recognized by CPython for a limited set of (case
insensitive) aliases: utf-8, utf8, latin-1, latin1, iso-8859-1,
iso8859-1, mbcs (Windows only), ascii, us-ascii, utf-16, utf16, utf-32,
utf32, and the same using underscores instead of dashes.  Using
alternative aliases for these encodings may result in slower execution.

Changed in version 3.6: Optimization opportunity recognized for
us-ascii.

Many of the character sets support the same languages.  They vary in
individual characters (e.g.  whether the EURO SIGN is supported or not),
and in the assignment of characters to code positions.  For the European
languages in particular, the following variants typically exist:

   * an ISO 8859 codeset

   * a Microsoft Windows code page, which is typically derived from an
     8859 codeset, but replaces control characters with additional
     graphic characters

   * an IBM EBCDIC code page

   * an IBM PC code page, which is ASCII compatible

Codec                 Aliases                              Languages
                                                           
------------------------------------------------------------------------------------------------
                                                           
ascii                 646, us-ascii                        English
                                                           
                                                           
big5                  big5-tw, csbig5                      Traditional Chinese
                                                           
                                                           
big5hkscs             big5-hkscs, hkscs                    Traditional Chinese
                                                           
                                                           
cp037                 IBM037, IBM039                       English
                                                           
                                                           
cp273                 273, IBM273, csIBM273                German
                                                           
                                                           Added in version 3.4.
                                                           
                                                           
cp424                 EBCDIC-CP-HE, IBM424                 Hebrew
                                                           
                                                           
cp437                 437, IBM437                          English
                                                           
                                                           
cp500                 EBCDIC-CP-BE, EBCDIC-CP-CH, IBM500   Western Europe
                                                           
                                                           
cp720                                                      Arabic
                                                           
                                                           
cp737                                                      Greek
                                                           
                                                           
cp775                 IBM775                               Baltic languages
                                                           
                                                           
cp850                 850, IBM850                          Western Europe
                                                           
                                                           
cp852                 852, IBM852                          Central and Eastern Europe
                                                           
                                                           
cp855                 855, IBM855                          Belarusian, Bulgarian, Macedonian,
                                                           Russian, Serbian
                                                           
                                                           
cp856                                                      Hebrew
                                                           
                                                           
cp857                 857, IBM857                          Turkish
                                                           
                                                           
cp858                 858, IBM858                          Western Europe
                                                           
                                                           
cp860                 860, IBM860                          Portuguese
                                                           
                                                           
cp861                 861, CP-IS, IBM861                   Icelandic
                                                           
                                                           
cp862                 862, IBM862                          Hebrew
                                                           
                                                           
cp863                 863, IBM863                          Canadian
                                                           
                                                           
cp864                 IBM864                               Arabic
                                                           
                                                           
cp865                 865, IBM865                          Danish, Norwegian
                                                           
                                                           
cp866                 866, IBM866                          Russian
                                                           
                                                           
cp869                 869, CP-GR, IBM869                   Greek
                                                           
                                                           
cp874                                                      Thai
                                                           
                                                           
cp875                                                      Greek
                                                           
                                                           
cp932                 932, ms932, mskanji, ms-kanji,       Japanese
                      windows-31j                          
                      
                                                           
cp949                 949, ms949, uhc                      Korean
                                                           
                                                           
cp950                 950, ms950                           Traditional Chinese
                                                           
                                                           
cp1006                                                     Urdu
                                                           
                                                           
cp1026                ibm1026                              Turkish
                                                           
                                                           
cp1125                1125, ibm1125, cp866u, ruscii        Ukrainian
                                                           
                                                           Added in version 3.4.
                                                           
                                                           
cp1140                ibm1140                              Western Europe
                                                           
                                                           
cp1250                windows-1250                         Central and Eastern Europe
                                                           
                                                           
cp1251                windows-1251                         Belarusian, Bulgarian, Macedonian,
                                                           Russian, Serbian
                                                           
                                                           
cp1252                windows-1252                         Western Europe
                                                           
                                                           
cp1253                windows-1253                         Greek
                                                           
                                                           
cp1254                windows-1254                         Turkish
                                                           
                                                           
cp1255                windows-1255                         Hebrew
                                                           
                                                           
cp1256                windows-1256                         Arabic
                                                           
                                                           
cp1257                windows-1257                         Baltic languages
                                                           
                                                           
cp1258                windows-1258                         Vietnamese
                                                           
                                                           
euc_jp                eucjp, ujis, u-jis                   Japanese
                                                           
                                                           
euc_jis_2004          jisx0213, eucjis2004                 Japanese
                                                           
                                                           
euc_jisx0213          eucjisx0213                          Japanese
                                                           
                                                           
euc_kr                euckr, korean, ksc5601, ks_c-5601,   Korean
                      ks_c-5601-1987, ksx1001, ks_x-1001   
                      
                                                           
gb2312                chinese, csiso58gb231280, euc-cn,    Simplified Chinese
                      euccn, eucgb2312-cn, gb2312-1980,    
                      gb2312-80, iso-ir-58
                      
                                                           
gbk                   936, cp936, ms936                    Unified Chinese
                                                           
                                                           
gb18030               gb18030-2000                         Unified Chinese
                                                           
                                                           
hz                    hzgb, hz-gb, hz-gb-2312              Simplified Chinese
                                                           
                                                           
iso2022_jp            csiso2022jp, iso2022jp,              Japanese
                      iso-2022-jp                          
                      
                                                           
iso2022_jp_1          iso2022jp-1, iso-2022-jp-1           Japanese
                                                           
                                                           
iso2022_jp_2          iso2022jp-2, iso-2022-jp-2           Japanese, Korean, Simplified
                                                           Chinese, Western Europe, Greek
                                                           
                                                           
iso2022_jp_2004       iso2022jp-2004, iso-2022-jp-2004     Japanese
                                                           
                                                           
iso2022_jp_3          iso2022jp-3, iso-2022-jp-3           Japanese
                                                           
                                                           
iso2022_jp_ext        iso2022jp-ext, iso-2022-jp-ext       Japanese
                                                           
                                                           
iso2022_kr            csiso2022kr, iso2022kr,              Korean
                      iso-2022-kr                          
                      
                                                           
latin_1               iso-8859-1, iso8859-1, 8859,         Western Europe
                      cp819, latin, latin1, L1             
                      
                                                           
iso8859_2             iso-8859-2, latin2, L2               Central and Eastern Europe
                                                           
                                                           
iso8859_3             iso-8859-3, latin3, L3               Esperanto, Maltese
                                                           
                                                           
iso8859_4             iso-8859-4, latin4, L4               Northern Europe
                                                           
                                                           
iso8859_5             iso-8859-5, cyrillic                 Belarusian, Bulgarian, Macedonian,
                                                           Russian, Serbian
                                                           
                                                           
iso8859_6             iso-8859-6, arabic                   Arabic
                                                           
                                                           
iso8859_7             iso-8859-7, greek, greek8            Greek
                                                           
                                                           
iso8859_8             iso-8859-8, hebrew                   Hebrew
                                                           
                                                           
iso8859_9             iso-8859-9, latin5, L5               Turkish
                                                           
                                                           
iso8859_10            iso-8859-10, latin6, L6              Nordic languages
                                                           
                                                           
iso8859_11            iso-8859-11, thai                    Thai languages
                                                           
                                                           
iso8859_13            iso-8859-13, latin7, L7              Baltic languages
                                                           
                                                           
iso8859_14            iso-8859-14, latin8, L8              Celtic languages
                                                           
                                                           
iso8859_15            iso-8859-15, latin9, L9              Western Europe
                                                           
                                                           
iso8859_16            iso-8859-16, latin10, L10            South-Eastern Europe
                                                           
                                                           
johab                 cp1361, ms1361                       Korean
                                                           
                                                           
koi8_r                                                     Russian
                                                           
                                                           
koi8_t                                                     Tajik
                                                           
                                                           Added in version 3.5.
                                                           
                                                           
koi8_u                                                     Ukrainian
                                                           
                                                           
kz1048                kz_1048, strk1048_2002, rk1048       Kazakh
                                                           
                                                           Added in version 3.5.
                                                           
                                                           
mac_cyrillic          maccyrillic                          Belarusian, Bulgarian, Macedonian,
                                                           Russian, Serbian
                                                           
                                                           
mac_greek             macgreek                             Greek
                                                           
                                                           
mac_iceland           maciceland                           Icelandic
                                                           
                                                           
mac_latin2            maclatin2, maccentraleurope,         Central and Eastern Europe
                      mac_centeuro                         
                      
                                                           
mac_roman             macroman, macintosh                  Western Europe
                                                           
                                                           
mac_turkish           macturkish                           Turkish
                                                           
                                                           
ptcp154               csptcp154, pt154, cp154,             Kazakh
                      cyrillic-asian                       
                      
                                                           
shift_jis             csshiftjis, shiftjis, sjis, s_jis    Japanese
                                                           
                                                           
shift_jis_2004        shiftjis2004, sjis_2004, sjis2004    Japanese
                                                           
                                                           
shift_jisx0213        shiftjisx0213, sjisx0213,            Japanese
                      s_jisx0213                           
                      
                                                           
utf_32                U32, utf32                           all languages
                                                           
                                                           
utf_32_be             UTF-32BE                             all languages
                                                           
                                                           
utf_32_le             UTF-32LE                             all languages
                                                           
                                                           
utf_16                U16, utf16                           all languages
                                                           
                                                           
utf_16_be             UTF-16BE                             all languages
                                                           
                                                           
utf_16_le             UTF-16LE                             all languages
                                                           
                                                           
utf_7                 U7, unicode-1-1-utf-7                all languages
                                                           
                                                           
utf_8                 U8, UTF, utf8, cp65001               all languages
                                                           
                                                           
utf_8_sig                                                  all languages
                                                           

Changed in version 3.4: The utf-16* and utf-32* encoders no longer allow
surrogate code points (‘U+D800’–‘U+DFFF’) to be encoded.  The utf-32*
decoders no longer decode byte sequences that correspond to surrogate
code points.

Changed in version 3.8: ‘cp65001’ is now an alias to ‘utf_8’.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/encodings/aliases.py


File: python.info,  Node: Python Specific Encodings,  Next: encodings — Encodings package,  Prev: Standard Encodings,  Up: codecs — Codec registry and base classes

5.7.2.14 Python Specific Encodings
..................................

A number of predefined codecs are specific to Python, so their codec
names have no meaning outside Python.  These are listed in the tables
below based on the expected input and output types (note that while text
encodings are the most common use case for codecs, the underlying codec
infrastructure supports arbitrary data transforms rather than just text
encodings).  For asymmetric codecs, the stated meaning describes the
encoding direction.

* Menu:

* Text Encodings::
* Binary Transforms::
* Standalone Codec Functions::
* Text Transforms::


File: python.info,  Node: Text Encodings,  Next: Binary Transforms,  Up: Python Specific Encodings

5.7.2.15 Text Encodings
.......................

The following codecs provide *note str: 44f. to *note bytes: 1c2.
encoding and *note bytes-like object: d55. to ‘str’ decoding, similar to
the Unicode text encodings.

Codec                    Aliases       Meaning
                                       
-----------------------------------------------------------------------
                                       
idna                                   Implement RFC 3490(1), see
                                       also
                                       *note encodings.idna: 52.
                                       Only ‘errors='strict'’ is
                                       supported.
                                       
                                       
mbcs                     ansi, dbcs    Windows only: Encode the
                                       operand according to the ANSI
                                       codepage (CP_ACP).
                                       
                                       
oem                                    Windows only: Encode the
                                       operand according to the OEM
                                       codepage (CP_OEMCP).
                                       
                                       Added in version 3.6.
                                       
                                       
palmos                                 Encoding of PalmOS 3.5.
                                       
                                       
punycode                               Implement RFC 3492(2).
                                       Stateful codecs are not
                                       supported.
                                       
                                       
raw_unicode_escape                     Latin-1 encoding with
                                       ‘\uXXXX’ and ‘\UXXXXXXXX’ for
                                       other code points.  Existing
                                       backslashes are not escaped
                                       in any way.  It is used in
                                       the Python pickle protocol.
                                       
                                       
undefined                              This Codec should only be
                                       used for testing purposes.
                                       
                                       Raise an exception for all
                                       conversions, even empty
                                       strings.  The error handler
                                       is ignored.
                                       
                                       
unicode_escape                         Encoding suitable as the
                                       contents of a Unicode literal
                                       in ASCII-encoded Python
                                       source code, except that
                                       quotes are not escaped.
                                       Decode from Latin-1 source
                                       code.  Beware that Python
                                       source code actually uses
                                       UTF-8 by default.
                                       

Changed in version 3.8: “unicode_internal” codec is removed.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3490.html

   (2) https://datatracker.ietf.org/doc/html/rfc3492.html


File: python.info,  Node: Binary Transforms,  Next: Standalone Codec Functions,  Prev: Text Encodings,  Up: Python Specific Encodings

5.7.2.16 Binary Transforms
..........................

The following codecs provide binary transforms: *note bytes-like object:
d55. to *note bytes: 1c2. mappings.  They are not supported by *note
bytes.decode(): 8df. (which only produces *note str: 44f. output).

Codec                      Aliases                Meaning                            Encoder / decoder
                                                                                     
------------------------------------------------------------------------------------------------------------------------
                                                                                     
base64_codec (1)           base64, base_64        Convert the operand to multiline   *note base64.encodebytes(): 95d.
                                                  MIME base64 (the result always     /
                                                  includes a trailing ‘'\n'’).       *note base64.decodebytes(): 95e.
                                                                                     
                                                  Changed in version 3.4: accepts
                                                  any
                                                  *note bytes-like object: d55. as
                                                  input for encoding and decoding
                                                  
                                                                                     
bz2_codec                  bz2                    Compress the operand using bz2.    *note bz2.compress(): 25cc. /
                                                                                     *note bz2.decompress(): 10d2.
                                                                                     
                                                                                     
hex_codec                  hex                    Convert the operand to             *note binascii.b2a_hex(): 25cd.
                                                  hexadecimal representation, with   /
                                                  two digits per byte.               *note binascii.a2b_hex(): 25ce.
                                                                                     
                                                                                     
quopri_codec               quopri,                Convert the operand to MIME        *note quopri.encode(): 25cf.
                           quotedprintable,       quoted printable.                  with ‘quotetabs=True’ /
                           quoted_printable                                          *note quopri.decode(): 25d0.
                                                                                     
                                                                                     
uu_codec                   uu                     Convert the operand using
                                                  uuencode.
                                                  
                                                                                     
zlib_codec                 zip, zlib              Compress the operand using gzip.   *note zlib.compress(): 642. /
                                                                                     *note zlib.decompress(): d35.
                                                                                     

Added in version 3.2: Restoration of the binary transforms.

Changed in version 3.4: Restoration of the aliases for the binary
transforms.

   ---------- Footnotes ----------

   (1) In addition to *note bytes-like objects: d55, ‘'base64_codec'’
also accepts ASCII-only instances of *note str: 44f. for decoding


File: python.info,  Node: Standalone Codec Functions,  Next: Text Transforms,  Prev: Binary Transforms,  Up: Python Specific Encodings

5.7.2.17 Standalone Codec Functions
...................................

The following functions provide encoding and decoding functionality
similar to codecs, but are not available as named codecs through *note
codecs.encode(): f38. or *note codecs.decode(): f39.  They are used
internally (for example, by *note pickle: a6.) and behave similarly to
the ‘string_escape’ codec that was removed in Python 3.

 -- Function: codecs.escape_encode (input, errors=None)

     Encode 'input' using escape sequences.  Similar to how *note
     repr(): 803. on bytes produces escaped byte values.

     'input' must be a *note bytes: 1c2. object.

     Returns a tuple ‘(output, length)’ where 'output' is a *note bytes:
     1c2. object and 'length' is the number of bytes consumed.

 -- Function: codecs.escape_decode (input, errors=None)

     Decode 'input' from escape sequences back to the original bytes.

     'input' must be a *note bytes-like object: d55.

     Returns a tuple ‘(output, length)’ where 'output' is a *note bytes:
     1c2. object and 'length' is the number of bytes consumed.


File: python.info,  Node: Text Transforms,  Prev: Standalone Codec Functions,  Up: Python Specific Encodings

5.7.2.18 Text Transforms
........................

The following codec provides a text transform: a *note str: 44f. to
‘str’ mapping.  It is not supported by *note str.encode(): 8de. (which
only produces *note bytes: 1c2. output).

Codec                    Aliases       Meaning
                                       
-----------------------------------------------------------------------
                                       
rot_13                   rot13         Return the Caesar-cypher
                                       encryption of the operand.
                                       

Added in version 3.2: Restoration of the ‘rot_13’ text transform.

Changed in version 3.4: Restoration of the ‘rot13’ alias.


File: python.info,  Node: encodings — Encodings package,  Next: encodings idna — Internationalized Domain Names in Applications,  Prev: Python Specific Encodings,  Up: codecs — Codec registry and base classes

5.7.2.19 ‘encodings’ — Encodings package
........................................

This module implements the following functions:

 -- Function: encodings.normalize_encoding (encoding)

     Normalize encoding name 'encoding'.

     Normalization works as follows: all non-alphanumeric characters
     except the dot used for Python package names are collapsed and
     replaced with a single underscore, leading and trailing underscores
     are removed.  For example, ‘' -;#'’ becomes ‘'_'’.

     Note that 'encoding' should be ASCII only.

     Note: The following function should not be used directly, except
     for testing purposes; *note codecs.lookup(): 96d. should be used
     instead.

 -- Function: encodings.search_function (encoding)

     Search for the codec module corresponding to the given encoding
     name 'encoding'.

     This function first normalizes the 'encoding' using *note
     normalize_encoding(): 801, then looks for a corresponding alias.
     It attempts to import a codec module from the encodings package
     using either the alias or the normalized name.  If the module is
     found and defines a valid ‘getregentry()’ function that returns a
     *note codecs.CodecInfo: 180b. object, the codec is cached and
     returned.

     If the codec module defines a ‘getaliases()’ function any returned
     aliases are registered for future use.

This module implements the following exception:

 -- Exception: encodings.CodecRegistryError

     Raised when a codec is invalid or incompatible.


File: python.info,  Node: encodings idna — Internationalized Domain Names in Applications,  Next: encodings mbcs — Windows ANSI codepage,  Prev: encodings — Encodings package,  Up: codecs — Codec registry and base classes

5.7.2.20 ‘encodings.idna’ — Internationalized Domain Names in Applications
..........................................................................

This module implements RFC 3490(1) (Internationalized Domain Names in
Applications) and RFC 3492(2) (Nameprep: A Stringprep Profile for
Internationalized Domain Names (IDN)). It builds upon the ‘punycode’
encoding and *note stringprep: d4.

If you need the IDNA 2008 standard from RFC 5891(3) and RFC 5895(4), use
the third-party idna(5) module.

These RFCs together define a protocol to support non-ASCII characters in
domain names.  A domain name containing non-ASCII characters (such as
‘www.Alliancefrançaise.nu’) is converted into an ASCII-compatible
encoding (ACE, such as ‘www.xn--alliancefranaise-npb.nu’).  The ACE form
of the domain name is then used in all places where arbitrary characters
are not allowed by the protocol, such as DNS queries, HTTP ‘Host’
fields, and so on.  This conversion is carried out in the application;
if possible invisible to the user: The application should transparently
convert Unicode domain labels to IDNA on the wire, and convert back ACE
labels to Unicode before presenting them to the user.

Python supports this conversion in several ways: the ‘idna’ codec
performs conversion between Unicode and ACE, separating an input string
into labels based on the separator characters defined in section 3.1 of
RFC 3490(6) and converting each label to ACE as required, and conversely
separating an input byte string into labels based on the ‘.’ separator
and converting any ACE labels found into unicode.  Furthermore, the
*note socket: cc. module transparently converts Unicode host names to
ACE, so that applications need not be concerned about converting host
names themselves when they pass them to the socket module.  On top of
that, modules that have host names as function parameters, such as *note
http.client: 6f. and *note ftplib: 5e, accept Unicode host names
(‘http.client’ then also transparently sends an IDNA hostname in the
‘Host’ field if it sends that field at all).

When receiving host names from the wire (such as in reverse name
lookup), no automatic conversion to Unicode is performed: applications
wishing to present such host names to the user should decode them to
Unicode.

The module ‘encodings.idna’ also implements the nameprep procedure,
which performs certain normalizations on host names, to achieve
case-insensitivity of international domain names, and to unify similar
characters.  The nameprep functions can be used directly if desired.

 -- Function: encodings.idna.nameprep (label)

     Return the nameprepped version of 'label'.  The implementation
     currently assumes query strings, so ‘AllowUnassigned’ is true.

 -- Function: encodings.idna.ToASCII (label)

     Convert a label to ASCII, as specified in RFC 3490(7).
     ‘UseSTD3ASCIIRules’ is assumed to be false.

 -- Function: encodings.idna.ToUnicode (label)

     Convert a label to Unicode, as specified in RFC 3490(8).

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3490.html

   (2) https://datatracker.ietf.org/doc/html/rfc3492.html

   (3) https://datatracker.ietf.org/doc/html/rfc5891.html

   (4) https://datatracker.ietf.org/doc/html/rfc5895.html

   (5) https://pypi.org/project/idna/

   (6) https://datatracker.ietf.org/doc/html/rfc3490.html#section-3.1

   (7) https://datatracker.ietf.org/doc/html/rfc3490.html

   (8) https://datatracker.ietf.org/doc/html/rfc3490.html


File: python.info,  Node: encodings mbcs — Windows ANSI codepage,  Next: encodings utf_8_sig — UTF-8 codec with BOM signature,  Prev: encodings idna — Internationalized Domain Names in Applications,  Up: codecs — Codec registry and base classes

5.7.2.21 ‘encodings.mbcs’ — Windows ANSI codepage
.................................................

This module implements the ANSI codepage (CP_ACP).

*note Availability: 1ef7.: Windows.

Changed in version 3.2: Before 3.2, the 'errors' argument was ignored;
‘'replace'’ was always used to encode, and ‘'ignore'’ to decode.

Changed in version 3.3: Support any error handler.


File: python.info,  Node: encodings utf_8_sig — UTF-8 codec with BOM signature,  Prev: encodings mbcs — Windows ANSI codepage,  Up: codecs — Codec registry and base classes

5.7.2.22 ‘encodings.utf_8_sig’ — UTF-8 codec with BOM signature
...............................................................

This module implements a variant of the UTF-8 codec.  On encoding, a
UTF-8 encoded BOM will be prepended to the UTF-8 encoded bytes.  For the
stateful encoder this is only done once (on the first write to the byte
stream).  On decoding, an optional UTF-8 encoded BOM at the start of the
data will be skipped.


File: python.info,  Node: Data Types,  Next: Numeric and Mathematical Modules,  Prev: Binary Data Services,  Up: The Python Standard Library

5.8 Data Types
==============

The modules described in this chapter provide a variety of specialized
data types such as dates and times, fixed-type arrays, heap queues,
double-ended queues, and enumerations.

Python also provides some built-in data types, in particular, *note
dict: 256, *note list: 614, *note set: 5dc. and *note frozenset: 5dd,
and *note tuple: 373.  The *note str: 44f. class is used to hold Unicode
strings, and the *note bytes: 1c2. and *note bytearray: 2ea. classes are
used to hold binary data.

The following modules are documented in this chapter:

* Menu:

* datetime — Basic date and time types::
* zoneinfo — IANA time zone support::
* calendar — General calendar-related functions::
* collections — Container datatypes::
* collections.abc — Abstract Base Classes for Containers: collections abc — Abstract Base Classes for Containers.
* heapq — Heap queue algorithm::
* bisect — Array bisection algorithm::
* array — Efficient arrays of numeric values::
* weakref — Weak references::
* types — Dynamic type creation and names for built-in types::
* copy — Shallow and deep copy operations::
* pprint — Data pretty printer::
* reprlib — Alternate repr() implementation: reprlib — Alternate repr implementation.
* enum — Support for enumerations::
* graphlib — Functionality to operate with graph-like structures::


File: python.info,  Node: datetime — Basic date and time types,  Next: zoneinfo — IANA time zone support,  Up: Data Types

5.8.1 ‘datetime’ — Basic date and time types
--------------------------------------------

'Source code:' Lib/datetime.py(1)

__________________________________________________________________

The ‘datetime’ module supplies classes for manipulating dates and times.

While date and time arithmetic is supported, the focus of the
implementation is on efficient attribute extraction for output
formatting and manipulation.

     Tip: Skip to *note the format codes: 25e4.

See also
........

Module *note calendar: 14.

     General calendar related functions.

Module *note time: ee.

     Time access and conversions.

Module *note zoneinfo: 134.

     Concrete time zones representing the IANA time zone database.

Package dateutil(2)

     Third-party library with expanded time zone and parsing support.

Package DateType(3)

     Third-party library that introduces distinct static types to e.g.
     allow *note static type checkers: 26d. to differentiate between
     naive and aware datetimes.

* Menu:

* Aware and Naive Objects::
* Constants::
* Available Types::
* timedelta Objects::
* date Objects::
* datetime Objects::
* time Objects::
* tzinfo Objects::
* timezone Objects::
* strftime() and strptime() Behavior: strftime and strptime Behavior.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/datetime.py

   (2) https://dateutil.readthedocs.io/en/stable/

   (3) https://pypi.org/project/DateType/


File: python.info,  Node: Aware and Naive Objects,  Next: Constants,  Up: datetime — Basic date and time types

5.8.1.1 Aware and Naive Objects
...............................

Date and time objects may be categorized as “aware” or “naive” depending
on whether or not they include time zone information.

With sufficient knowledge of applicable algorithmic and political time
adjustments, such as time zone and daylight saving time information, an
'aware' object can locate itself relative to other aware objects.  An
aware object represents a specific moment in time that is not open to
interpretation.  (1)

A 'naive' object does not contain enough information to unambiguously
locate itself relative to other date/time objects.  Whether a naive
object represents Coordinated Universal Time (UTC), local time, or time
in some other time zone is purely up to the program, just like it is up
to the program whether a particular number represents metres, miles, or
mass.  Naive objects are easy to understand and to work with, at the
cost of ignoring some aspects of reality.

For applications requiring aware objects, *note datetime: 1cc. and *note
time: 1ce. objects have an optional time zone information attribute,
‘tzinfo’, that can be set to an instance of a subclass of the abstract
‘tzinfo’ class.  These *note tzinfo: 5e1. objects capture information
about the offset from UTC time, the time zone name, and whether daylight
saving time is in effect.

Only one concrete *note tzinfo: 5e1. class, the *note timezone: 1103.
class, is supplied by the ‘datetime’ module.  The ‘timezone’ class can
represent simple time zones with fixed offsets from UTC, such as UTC
itself or North American EST and EDT time zones.  Supporting time zones
at deeper levels of detail is up to the application.  The rules for time
adjustment across the world are more political than rational, change
frequently, and there is no standard suitable for every application
aside from UTC.

   ---------- Footnotes ----------

   (1) If, that is, we ignore the effects of relativity.


File: python.info,  Node: Constants,  Next: Available Types,  Prev: Aware and Naive Objects,  Up: datetime — Basic date and time types

5.8.1.2 Constants
.................

The ‘datetime’ module exports the following constants:

 -- Data: datetime.MINYEAR

     The smallest year number allowed in a *note date: 1cd. or *note
     datetime: 1cc. object.  *note MINYEAR: 25e8. is 1.

 -- Data: datetime.MAXYEAR

     The largest year number allowed in a *note date: 1cd. or *note
     datetime: 1cc. object.  *note MAXYEAR: 25e9. is 9999.

 -- Data: datetime.UTC

     Alias for the UTC time zone singleton *note datetime.timezone.utc:
     617.

     Added in version 3.11.


File: python.info,  Node: Available Types,  Next: timedelta Objects,  Prev: Constants,  Up: datetime — Basic date and time types

5.8.1.3 Available Types
.......................

 -- Class: datetime.date

     An idealized naive date, assuming the current Gregorian calendar
     always was, and always will be, in effect.  Attributes: *note year:
     25eb, *note month: 25ec, and *note day: 25ed.

 -- Class: datetime.time

     An idealized time, independent of any particular day, assuming that
     every day has exactly 24*60*60 seconds.  (There is no notion of
     “leap seconds” here.)  Attributes: *note hour: 25ee, *note minute:
     25ef, *note second: 25f0, *note microsecond: 25f1, and *note
     tzinfo: 25f2.

 -- Class: datetime.datetime

     A combination of a date and a time.  Attributes: *note year: 25f3,
     *note month: 25f4, *note day: 25f5, *note hour: 25f6, *note minute:
     25f7, *note second: 25f8, *note microsecond: 25f9, and *note
     tzinfo: 25fa.

 -- Class: datetime.timedelta

     A duration expressing the difference between two *note datetime:
     1cc. or *note date: 1cd. instances to microsecond resolution.

 -- Class: datetime.tzinfo

     An abstract base class for time zone information objects.  These
     are used by the *note datetime: 1cc. and *note time: 1ce. classes
     to provide a customizable notion of time adjustment (for example,
     to account for time zone and/or daylight saving time).

 -- Class: datetime.timezone

     A class that implements the *note tzinfo: 5e1. abstract base class
     as a fixed offset from the UTC.

     Added in version 3.2.

Objects of these types are immutable.

Subclass relationships:

     object
         timedelta
         tzinfo
             timezone
         time
         date
             datetime

* Menu:

* Common Properties::
* Determining if an Object is Aware or Naive::


File: python.info,  Node: Common Properties,  Next: Determining if an Object is Aware or Naive,  Up: Available Types

5.8.1.4 Common Properties
.........................

The *note date: 1cd, *note datetime: 1cc, *note time: 1ce, and *note
timezone: 1103. types share these common features:

   - Objects of these types are immutable.

   - Objects of these types are *note hashable: 613, meaning that they
     can be used as dictionary keys.

   - Objects of these types support efficient pickling via the *note
     pickle: a6. module.


File: python.info,  Node: Determining if an Object is Aware or Naive,  Prev: Common Properties,  Up: Available Types

5.8.1.5 Determining if an Object is Aware or Naive
..................................................

Objects of the *note date: 1cd. type are always naive.

An object of type *note time: 1ce. or *note datetime: 1cc. may be aware
or naive.

A *note datetime: 1cc. object ‘d’ is aware if both of the following
hold:

  1. ‘d.tzinfo’ is not ‘None’

  2. ‘d.tzinfo.utcoffset(d)’ does not return ‘None’

Otherwise, ‘d’ is naive.

A *note time: 1ce. object ‘t’ is aware if both of the following hold:

  1. ‘t.tzinfo’ is not ‘None’

  2. ‘t.tzinfo.utcoffset(None)’ does not return ‘None’.

Otherwise, ‘t’ is naive.

The distinction between aware and naive doesn’t apply to *note
timedelta: 9da. objects.


File: python.info,  Node: timedelta Objects,  Next: date Objects,  Prev: Available Types,  Up: datetime — Basic date and time types

5.8.1.6 ‘timedelta’ Objects
...........................

A *note timedelta: 9da. object represents a duration, the difference
between two *note datetime: 1cc. or *note date: 1cd. instances.

 -- Class: datetime.timedelta (days=0, seconds=0, microseconds=0,
          milliseconds=0, minutes=0, hours=0, weeks=0)

     All arguments are optional and default to 0.  Arguments may be
     integers or floats, and may be positive or negative.

     Only 'days', 'seconds' and 'microseconds' are stored internally.
     Arguments are converted to those units:

        * A millisecond is converted to 1000 microseconds.

        * A minute is converted to 60 seconds.

        * An hour is converted to 3600 seconds.

        * A week is converted to 7 days.

     and days, seconds and microseconds are then normalized so that the
     representation is unique, with

        * ‘0 <= microseconds < 1000000’

        * ‘0 <= seconds < 3600*24’ (the number of seconds in one day)

        * ‘-999999999 <= days <= 999999999’

     The following example illustrates how any arguments besides 'days',
     'seconds' and 'microseconds' are “merged” and normalized into those
     three resulting attributes:

          >>> import datetime as dt
          >>> delta = dt.timedelta(
          ...     days=50,
          ...     seconds=27,
          ...     microseconds=10,
          ...     milliseconds=29000,
          ...     minutes=5,
          ...     hours=8,
          ...     weeks=2
          ... )
          >>> # Only days, seconds, and microseconds remain
          >>> delta
          datetime.timedelta(days=64, seconds=29156, microseconds=10)

          Tip: ‘import datetime as dt’ instead of ‘import datetime’ or
          ‘from datetime import datetime’ to avoid confusion between the
          module and the class.  See How I Import Python’s datetime
          Module(1).

     If any argument is a float and there are fractional microseconds,
     the fractional microseconds left over from all arguments are
     combined and their sum is rounded to the nearest microsecond using
     round-half-to-even tiebreaker.  If no argument is a float, the
     conversion and normalization processes are exact (no information is
     lost).

     If the normalized value of days lies outside the indicated range,
     *note OverflowError: 888. is raised.

     Note that normalization of negative values may be surprising at
     first.  For example:

          >>> import datetime as dt
          >>> d = dt.timedelta(microseconds=-1)
          >>> (d.days, d.seconds, d.microseconds)
          (-1, 86399, 999999)

     Since the string representation of ‘timedelta’ objects can be
     confusing, use the following recipe to produce a more readable
     format:

          >>> def pretty_timedelta(td):
          ...     if td.days >= 0:
          ...         return str(td)
          ...     return f'-({-td!s})'
          ...
          >>> d = timedelta(hours=-1)
          >>> str(d)  # not human-friendly
          '-1 day, 23:00:00'
          >>> pretty_timedelta(d)
          '-(1:00:00)'

Class attributes:

 -- Attribute: timedelta.min

     The most negative *note timedelta: 9da. object,
     ‘timedelta(-999999999)’.

 -- Attribute: timedelta.max

     The most positive *note timedelta: 9da. object,
     ‘timedelta(days=999999999, hours=23, minutes=59, seconds=59,
     microseconds=999999)’.

 -- Attribute: timedelta.resolution

     The smallest possible difference between non-equal *note timedelta:
     9da. objects, ‘timedelta(microseconds=1)’.

Note that, because of normalization, ‘timedelta.max’ is greater than
‘-timedelta.min’.  ‘-timedelta.max’ is not representable as a *note
timedelta: 9da. object.

Instance attributes (read-only):

 -- Attribute: timedelta.days

     Between -999,999,999 and 999,999,999 inclusive.

 -- Attribute: timedelta.seconds

     Between 0 and 86,399 inclusive.

          Caution: It is a somewhat common bug for code to
          unintentionally use this attribute when it is actually
          intended to get a *note total_seconds(): 134f. value instead:

               >>> import datetime as dt
               >>> duration = dt.timedelta(seconds=11235813)
               >>> duration.days, duration.seconds
               (130, 3813)
               >>> duration.total_seconds()
               11235813.0

 -- Attribute: timedelta.microseconds

     Between 0 and 999,999 inclusive.

Supported operations:

Operation                            Result
                                     
-----------------------------------------------------------------------------------------
                                     
‘t1 = t2 + t3’                       Sum of ‘t2’ and ‘t3’.  Afterwards ‘t1 - t2 == t3’
                                     and ‘t1 - t3 == t2’ are true.  (1)
                                     
                                     
‘t1 = t2 - t3’                       Difference of ‘t2’ and ‘t3’.  Afterwards ‘t1 ==
                                     t2 - t3’ and ‘t2 == t1 + t3’ are true.  (1)(6)
                                     
                                     
‘t1 = t2 * i or t1 = i * t2’         Delta multiplied by an integer.  Afterwards ‘t1
                                     // i == t2’ is true, provided ‘i != 0’.
                                     
                                     
                                     In general, ‘t1 * i == t1 * (i-1) + t1’ is true.
                                     (1)
                                     
                                     
‘t1 = t2 * f or t1 = f * t2’         Delta multiplied by a float.  The result is
                                     rounded to the nearest multiple of
                                     timedelta.resolution using round-half-to-even.
                                     
                                     
‘f = t2 / t3’                        Division (3) of overall duration ‘t2’ by interval
                                     unit ‘t3’.  Returns a *note float: 2f7. object.
                                     
                                     
‘t1 = t2 / f or t1 = t2 / i’         Delta divided by a float or an int.  The result
                                     is rounded to the nearest multiple of
                                     timedelta.resolution using round-half-to-even.
                                     
                                     
‘t1 = t2 // i’ or ‘t1 = t2 // t3’    The floor is computed and the remainder (if any)
                                     is thrown away.  In the second case, an integer
                                     is returned.  (3)
                                     
                                     
‘t1 = t2 % t3’                       The remainder is computed as a
                                     *note timedelta: 9da. object.  (3)
                                     
                                     
‘q, r = divmod(t1, t2)’              Computes the quotient and the remainder: ‘q = t1
                                     // t2’ (3) and ‘r = t1 % t2’.  ‘q’ is an integer
                                     and ‘r’ is a *note timedelta: 9da. object.
                                     
                                     
‘+t1’                                Returns a *note timedelta: 9da. object with the
                                     same value.  (2)
                                     
                                     
‘-t1’                                Equivalent to ‘timedelta(-t1.days, -t1.seconds,
                                     -t1.microseconds)’, and to ‘t1 * -1’.  (1)(4)
                                     
                                     
‘abs(t)’                             Equivalent to ‘+t’ when ‘t.days >= 0’, and to
                                     ‘-t’ when ‘t.days < 0’.  (2)
                                     
                                     
‘str(t)’                             Returns a string in the form ‘[D day[s],
                                     ][H]H:MM:SS[.UUUUUU]’, where D is negative for
                                     negative ‘t’.  (5)
                                     
                                     
‘repr(t)’                            Returns a string representation of the
                                     *note timedelta: 9da. object as a constructor
                                     call with canonical attribute values.
                                     

Notes:

  1. This is exact but may overflow.

  2. This is exact and cannot overflow.

  3. Division by zero raises *note ZeroDivisionError: 94f.

  4. ‘-timedelta.max’ is not representable as a *note timedelta: 9da.
     object.

  5. String representations of *note timedelta: 9da. objects are
     normalized similarly to their internal representation.  This leads
     to somewhat unusual results for negative timedeltas.  For example:

          >>> timedelta(hours=-5)
          datetime.timedelta(days=-1, seconds=68400)
          >>> print(_)
          -1 day, 19:00:00

  6. The expression ‘t2 - t3’ will always be equal to the expression ‘t2
     + (-t3)’ except when t3 is equal to ‘timedelta.max’; in that case
     the former will produce a result while the latter will overflow.

In addition to the operations listed above, *note timedelta: 9da.
objects support certain additions and subtractions with *note date: 1cd.
and *note datetime: 1cc. objects (see below).

Changed in version 3.2: Floor division and true division of a *note
timedelta: 9da. object by another ‘timedelta’ object are now supported,
as are remainder operations and the *note divmod(): 9ac. function.  True
division and multiplication of a ‘timedelta’ object by a *note float:
2f7. object are now supported.

*note timedelta: 9da. objects support equality and order comparisons.

In Boolean contexts, a *note timedelta: 9da. object is considered to be
true if and only if it isn’t equal to ‘timedelta(0)’.

Instance methods:

 -- Method: timedelta.total_seconds ()

     Return the total number of seconds contained in the duration.
     Equivalent to ‘td / timedelta(seconds=1)’.  For interval units
     other than seconds, use the division form directly (e.g.  ‘td /
     timedelta(microseconds=1)’).

     Note that for very large time intervals (greater than 270 years on
     most platforms) this method will lose microsecond accuracy.

     Added in version 3.2.

* Menu:

* Examples of usage; timedelta: Examples of usage timedelta.

   ---------- Footnotes ----------

   (1) 
https://adamj.eu/tech/2019/09/12/how-i-import-pythons-datetime-module/


File: python.info,  Node: Examples of usage timedelta,  Up: timedelta Objects

5.8.1.7 Examples of usage: ‘timedelta’
......................................

An additional example of normalization:

     >>> # Components of another_year add up to exactly 365 days
     >>> import datetime as dt
     >>> year = dt.timedelta(days=365)
     >>> another_year = dt.timedelta(weeks=40, days=84, hours=23,
     ...                             minutes=50, seconds=600)
     >>> year == another_year
     True
     >>> year.total_seconds()
     31536000.0

Examples of *note timedelta: 9da. arithmetic:

     >>> import datetime as dt
     >>> year = dt.timedelta(days=365)
     >>> ten_years = 10 * year
     >>> ten_years
     datetime.timedelta(days=3650)
     >>> ten_years.days // 365
     10
     >>> nine_years = ten_years - year
     >>> nine_years
     datetime.timedelta(days=3285)
     >>> three_years = nine_years // 3
     >>> three_years, three_years.days // 365
     (datetime.timedelta(days=1095), 3)


File: python.info,  Node: date Objects,  Next: datetime Objects,  Prev: timedelta Objects,  Up: datetime — Basic date and time types

5.8.1.8 ‘date’ Objects
......................

A *note date: 1cd. object represents a date (year, month and day) in an
idealized calendar, the current Gregorian calendar indefinitely extended
in both directions.

January 1 of year 1 is called day number 1, January 2 of year 1 is
called day number 2, and so on.  (1)

 -- Class: datetime.date (year, month, day)

     All arguments are required.  Arguments must be integers, in the
     following ranges:

        * ‘MINYEAR <= year <= MAXYEAR’

        * ‘1 <= month <= 12’

        * ‘1 <= day <= number of days in the given month and year’

     If an argument outside those ranges is given, *note ValueError:
     202. is raised.

Other constructors, all class methods:

 -- Method: classmethod date.today ()

     Return the current local date.

     This is equivalent to ‘date.fromtimestamp(time.time())’.

 -- Method: classmethod date.fromtimestamp (timestamp)

     Return the local date corresponding to the POSIX timestamp, such as
     is returned by *note time.time(): 254.

     This may raise *note OverflowError: 888, if the timestamp is out of
     the range of values supported by the platform C ‘localtime()’
     function, and *note OSError: 41a. on ‘localtime()’ failure.  It’s
     common for this to be restricted to years from 1970 through 2038.
     Note that on non-POSIX systems that include leap seconds in their
     notion of a timestamp, leap seconds are ignored by
     ‘fromtimestamp()’.

     Changed in version 3.3: Raise *note OverflowError: 888. instead of
     *note ValueError: 202. if the timestamp is out of the range of
     values supported by the platform C ‘localtime()’ function.  Raise
     *note OSError: 41a. instead of ‘ValueError’ on ‘localtime()’
     failure.

 -- Method: classmethod date.fromordinal (ordinal)

     Return the date corresponding to the proleptic Gregorian ordinal,
     where January 1 of year 1 has ordinal 1.

     *note ValueError: 202. is raised unless ‘1 <= ordinal <=
     date.max.toordinal()’.  For any date ‘d’,
     ‘date.fromordinal(d.toordinal()) == d’.

 -- Method: classmethod date.fromisoformat (date_string)

     Return a *note date: 1cd. corresponding to a 'date_string' given in
     any valid ISO 8601 format, with the following exceptions:

       1. Reduced precision dates are not currently supported
          (‘YYYY-MM’, ‘YYYY’).

       2. Extended date representations are not currently supported
          (‘±YYYYYY-MM-DD’).

       3. Ordinal dates are not currently supported (‘YYYY-OOO’).

     Examples:

          >>> import datetime as dt
          >>> dt.date.fromisoformat('2019-12-04')
          datetime.date(2019, 12, 4)
          >>> dt.date.fromisoformat('20191204')
          datetime.date(2019, 12, 4)
          >>> dt.date.fromisoformat('2021-W01-1')
          datetime.date(2021, 1, 4)

     Added in version 3.7.

     Changed in version 3.11: Previously, this method only supported the
     format ‘YYYY-MM-DD’.

 -- Method: classmethod date.fromisocalendar (year, week, day)

     Return a *note date: 1cd. corresponding to the ISO calendar date
     specified by year, week and day.  This is the inverse of the
     function *note date.isocalendar(): 8fe.

     Added in version 3.8.

Class attributes:

 -- Attribute: date.min

     The earliest representable date, ‘date(MINYEAR, 1, 1)’.

 -- Attribute: date.max

     The latest representable date, ‘date(MAXYEAR, 12, 31)’.

 -- Attribute: date.resolution

     The smallest possible difference between non-equal date objects,
     ‘timedelta(days=1)’.

Instance attributes (read-only):

 -- Attribute: date.year

     Between *note MINYEAR: 25e8. and *note MAXYEAR: 25e9. inclusive.

 -- Attribute: date.month

     Between 1 and 12 inclusive.

 -- Attribute: date.day

     Between 1 and the number of days in the given month of the given
     year.

Supported operations:

Operation                           Result
                                    
---------------------------------------------------------------------------------------
                                    
‘date2 = date1 + timedelta’         ‘date2’ will be ‘timedelta.days’ days after
                                    ‘date1’.  (1)
                                    
                                    
‘date2 = date1 - timedelta’         Computes ‘date2’ such that ‘date2 + timedelta ==
                                    date1’.  (2)
                                    
                                    
‘timedelta = date1 - date2’         (3)
                                    
                                    
     ‘date1 == date2’               Equality comparison.  (4)
     ‘date1 != date2’               

     ‘date1 < date2’                Order comparison.  (5)
     ‘date1 > date2’                
     ‘date1 <= date2’
     ‘date1 >= date2’

Notes:

  1. 'date2' is moved forward in time if ‘timedelta.days > 0’, or
     backward if ‘timedelta.days < 0’.  Afterward ‘date2 - date1 ==
     timedelta.days’.  ‘timedelta.seconds’ and ‘timedelta.microseconds’
     are ignored.  *note OverflowError: 888. is raised if ‘date2.year’
     would be smaller than *note MINYEAR: 25e8. or larger than *note
     MAXYEAR: 25e9.

  2. ‘timedelta.seconds’ and ‘timedelta.microseconds’ are ignored.

  3. This is exact, and cannot overflow.  ‘timedelta.seconds’ and
     ‘timedelta.microseconds’ are 0, and ‘date2 + timedelta == date1’
     after.

  4. *note date: 1cd. objects are equal if they represent the same date.

     ‘date’ objects that are not also *note datetime: 1cc. instances are
     never equal to ‘datetime’ objects, even if they represent the same
     date.

  5. 'date1' is considered less than 'date2' when 'date1' precedes
     'date2' in time.  In other words, ‘date1 < date2’ if and only if
     ‘date1.toordinal() < date2.toordinal()’.

     Order comparison between a *note date: 1cd. object that is not also
     a *note datetime: 1cc. instance and a ‘datetime’ object raises
     *note TypeError: 2c3.

Changed in version 3.13: Comparison between *note datetime: 1cc. object
and an instance of the *note date: 1cd. subclass that is not a
‘datetime’ subclass no longer converts the latter to ‘date’, ignoring
the time part and the time zone.  The default behavior can be changed by
overriding the special comparison methods in subclasses.

In Boolean contexts, all *note date: 1cd. objects are considered to be
true.

Instance methods:

 -- Method: date.replace (year=self.year, month=self.month,
          day=self.day)

     Return a new *note date: 1cd. object with the same values, but with
     specified parameters updated.

     Example:

          >>> import datetime as dt
          >>> d = dt.date(2002, 12, 31)
          >>> d.replace(day=26)
          datetime.date(2002, 12, 26)

     The generic function *note copy.replace(): 151. also supports *note
     date: 1cd. objects.

 -- Method: date.timetuple ()

     Return a *note time.struct_time: d11. such as returned by *note
     time.localtime(): 1548.

     The hours, minutes and seconds are 0, and the DST flag is -1.

     ‘d.timetuple()’ is equivalent to:

          time.struct_time((d.year, d.month, d.day, 0, 0, 0, d.weekday(), yday, -1))

     where ‘yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1’
     is the day number within the current year starting with 1 for
     January 1st.

 -- Method: date.toordinal ()

     Return the proleptic Gregorian ordinal of the date, where January 1
     of year 1 has ordinal 1.  For any *note date: 1cd. object ‘d’,
     ‘date.fromordinal(d.toordinal()) == d’.

 -- Method: date.weekday ()

     Return the day of the week as an integer, where Monday is 0 and
     Sunday is 6.  For example, ‘date(2002, 12, 4).weekday() == 2’, a
     Wednesday.  See also *note isoweekday(): 260e.

 -- Method: date.isoweekday ()

     Return the day of the week as an integer, where Monday is 1 and
     Sunday is 7.  For example, ‘date(2002, 12, 4).isoweekday() == 3’, a
     Wednesday.  See also *note weekday(): 260d, *note isocalendar():
     8fe.

 -- Method: date.isocalendar ()

     Return a *note named tuple: 651. object with three components:
     ‘year’, ‘week’ and ‘weekday’.

     The ISO calendar is a widely used variant of the Gregorian
     calendar.  (2)

     The ISO year consists of 52 or 53 full weeks, and where a week
     starts on a Monday and ends on a Sunday.  The first week of an ISO
     year is the first (Gregorian) calendar week of a year containing a
     Thursday.  This is called week number 1, and the ISO year of that
     Thursday is the same as its Gregorian year.

     For example, 2004 begins on a Thursday, so the first week of ISO
     year 2004 begins on Monday, 29 Dec 2003 and ends on Sunday, 4 Jan
     2004:

          >>> import datetime as dt
          >>> dt.date(2003, 12, 29).isocalendar()
          datetime.IsoCalendarDate(year=2004, week=1, weekday=1)
          >>> dt.date(2004, 1, 4).isocalendar()
          datetime.IsoCalendarDate(year=2004, week=1, weekday=7)

     Changed in version 3.9: Result changed from a tuple to a *note
     named tuple: 651.

 -- Method: date.isoformat ()

     Return a string representing the date in ISO 8601 format,
     ‘YYYY-MM-DD’:

          >>> import datetime as dt
          >>> dt.date(2002, 12, 4).isoformat()
          '2002-12-04'

 -- Method: date.__str__ ()

     For a date ‘d’, ‘str(d)’ is equivalent to ‘d.isoformat()’.

 -- Method: date.ctime ()

     Return a string representing the date:

          >>> import datetime as dt
          >>> dt.date(2002, 12, 4).ctime()
          'Wed Dec  4 00:00:00 2002'

     ‘d.ctime()’ is equivalent to:

          time.ctime(time.mktime(d.timetuple()))

     on platforms where the native C ‘ctime()’ function (which *note
     time.ctime(): 2612. invokes, but which ‘date.ctime()’ does not
     invoke) conforms to the C standard.

 -- Method: date.strftime (format)

     Return a string representing the date, controlled by an explicit
     format string.  Format codes referring to hours, minutes or seconds
     will see 0 values.  See also *note strftime() and strptime()
     Behavior: 18f9. and *note date.isoformat(): 260f.

 -- Method: date.__format__ (format)

     Same as *note date.strftime(): cb6.  This makes it possible to
     specify a format string for a *note date: 1cd. object in *note
     formatted string literals: 9b4. and when using *note str.format():
     624.  See also *note strftime() and strptime() Behavior: 18f9. and
     *note date.isoformat(): 260f.

* Menu:

* Examples of Usage; date: Examples of Usage date.

   ---------- Footnotes ----------

   (1) This matches the definition of the “proleptic Gregorian” calendar
in Dershowitz and Reingold’s book 'Calendrical Calculations', where it’s
the base calendar for all computations.  See the book for algorithms for
converting between proleptic Gregorian ordinals and many other calendar
systems.

   (2) See R. H. van Gent’s guide to the mathematics of the ISO 8601
calendar
(https://web.archive.org/web/20220531051136/https://webspace.science.uu.nl/~gent0113/calendar/isocalendar.htm)
for a good explanation.


File: python.info,  Node: Examples of Usage date,  Up: date Objects

5.8.1.9 Examples of Usage: ‘date’
.................................

Example of counting days to an event:

     >>> import time
     >>> import datetime as dt
     >>> today = dt.date.today()
     >>> today
     datetime.date(2007, 12, 5)
     >>> today == dt.date.fromtimestamp(time.time())
     True
     >>> my_birthday = dt.date(today.year, 6, 24)
     >>> if my_birthday < today:
     ...     my_birthday = my_birthday.replace(year=today.year + 1)
     ...
     >>> my_birthday
     datetime.date(2008, 6, 24)
     >>> time_to_birthday = abs(my_birthday - today)
     >>> time_to_birthday.days
     202

More examples of working with *note date: 1cd.:

     >>> import datetime as dt
     >>> d = dt.date.fromordinal(730920) # 730920th day after 1. 1. 0001
     >>> d
     datetime.date(2002, 3, 11)

     >>> # Methods related to formatting string output
     >>> d.isoformat()
     '2002-03-11'
     >>> d.strftime("%d/%m/%y")
     '11/03/02'
     >>> d.strftime("%A %d. %B %Y")
     'Monday 11. March 2002'
     >>> d.ctime()
     'Mon Mar 11 00:00:00 2002'
     >>> 'The {1} is {0:%d}, the {2} is {0:%B}.'.format(d, "day", "month")
     'The day is 11, the month is March.'

     >>> # Methods for to extracting 'components' under different calendars
     >>> t = d.timetuple()
     >>> for i in t:
     ...     print(i)
     2002                # year
     3                   # month
     11                  # day
     0
     0
     0
     0                   # weekday (0 = Monday)
     70                  # 70th day in the year
     -1
     >>> ic = d.isocalendar()
     >>> for i in ic:
     ...     print(i)
     2002                # ISO year
     11                  # ISO week number
     1                   # ISO day number ( 1 = Monday )

     >>> # A date object is immutable; all operations produce a new object
     >>> d.replace(year=2005)
     datetime.date(2005, 3, 11)


File: python.info,  Node: datetime Objects,  Next: time Objects,  Prev: date Objects,  Up: datetime — Basic date and time types

5.8.1.10 ‘datetime’ Objects
...........................

A *note datetime: 1cc. object is a single object containing all the
information from a *note date: 1cd. object and a *note time: 1ce.
object.

Like a *note date: 1cd. object, *note datetime: 1cc. assumes the current
Gregorian calendar extended in both directions; like a *note time: 1ce.
object, ‘datetime’ assumes there are exactly 3600*24 seconds in every
day.

Constructor:

 -- Class: datetime.datetime (year, month, day, hour=0, minute=0,
          second=0, microsecond=0, tzinfo=None, *, fold=0)

     The 'year', 'month' and 'day' arguments are required.  'tzinfo' may
     be ‘None’, or an instance of a *note tzinfo: 5e1. subclass.  The
     remaining arguments must be integers in the following ranges:

        * ‘MINYEAR <= year <= MAXYEAR’,

        * ‘1 <= month <= 12’,

        * ‘1 <= day <= number of days in the given month and year’,

        * ‘0 <= hour < 24’,

        * ‘0 <= minute < 60’,

        * ‘0 <= second < 60’,

        * ‘0 <= microsecond < 1000000’,

        * ‘fold in [0, 1]’.

     If an argument outside those ranges is given, *note ValueError:
     202. is raised.

     Changed in version 3.6: Added the 'fold' parameter.

Other constructors, all class methods:

 -- Method: classmethod datetime.today ()

     Return the current local date and time, with *note tzinfo: 25fa.
     ‘None’.

     Equivalent to:

          datetime.fromtimestamp(time.time())

     See also *note now(): 4ef, *note fromtimestamp(): 4f0.

     This method is functionally equivalent to *note now(): 4ef, but
     without a ‘tz’ parameter.

 -- Method: classmethod datetime.now (tz=None)

     Return the current local date and time.

     If optional argument 'tz' is ‘None’ or not specified, this is like
     *note today(): 2617, but, if possible, supplies more precision than
     can be gotten from going through a *note time.time(): 254.
     timestamp (for example, this may be possible on platforms supplying
     the C ‘gettimeofday()’ function).

     If 'tz' is not ‘None’, it must be an instance of a *note tzinfo:
     5e1. subclass, and the current date and time are converted to
     'tz'’s time zone.

     This function is preferred over *note today(): 2617. and *note
     utcnow(): 2fc.

          Note: Subsequent calls to ‘datetime.now()’ may return the same
          instant depending on the precision of the underlying clock.

 -- Method: classmethod datetime.utcnow ()

     Return the current UTC date and time, with *note tzinfo: 25fa.
     ‘None’.

     This is like *note now(): 4ef, but returns the current UTC date and
     time, as a naive *note datetime: 1cc. object.  An aware current UTC
     datetime can be obtained by calling ‘datetime.now(timezone.utc)’.
     See also ‘now()’.

          Warning: Because naive ‘datetime’ objects are treated by many
          ‘datetime’ methods as local times, it is preferred to use
          aware datetimes to represent times in UTC. As such, the
          recommended way to create an object representing the current
          time in UTC is by calling ‘datetime.now(timezone.utc)’.

     Deprecated since version 3.12: Use *note datetime.now(): 4ef. with
     *note UTC: 4f1. instead.

 -- Method: classmethod datetime.fromtimestamp (timestamp, tz=None)

     Return the local date and time corresponding to the POSIX
     timestamp, such as is returned by *note time.time(): 254.  If
     optional argument 'tz' is ‘None’ or not specified, the timestamp is
     converted to the platform’s local date and time, and the returned
     *note datetime: 1cc. object is naive.

     If 'tz' is not ‘None’, it must be an instance of a *note tzinfo:
     5e1. subclass, and the timestamp is converted to 'tz'’s time zone.

     ‘fromtimestamp()’ may raise *note OverflowError: 888, if the
     timestamp is out of the range of values supported by the platform C
     ‘localtime()’ or ‘gmtime()’ functions, and *note OSError: 41a. on
     ‘localtime()’ or ‘gmtime()’ failure.  It’s common for this to be
     restricted to years in 1970 through 2038.  Note that on non-POSIX
     systems that include leap seconds in their notion of a timestamp,
     leap seconds are ignored by ‘fromtimestamp()’, and then it’s
     possible to have two timestamps differing by a second that yield
     identical *note datetime: 1cc. objects.  This method is preferred
     over *note utcfromtimestamp(): 2fd.

     Changed in version 3.3: Raise *note OverflowError: 888. instead of
     *note ValueError: 202. if the timestamp is out of the range of
     values supported by the platform C ‘localtime()’ or ‘gmtime()’
     functions.  Raise *note OSError: 41a. instead of ‘ValueError’ on
     ‘localtime()’ or ‘gmtime()’ failure.

     Changed in version 3.6: ‘fromtimestamp()’ may return instances with
     *note fold: c78. set to 1.

 -- Method: classmethod datetime.utcfromtimestamp (timestamp)

     Return the UTC *note datetime: 1cc. corresponding to the POSIX
     timestamp, with *note tzinfo: 25fa. ‘None’.  (The resulting object
     is naive.)

     This may raise *note OverflowError: 888, if the timestamp is out of
     the range of values supported by the platform C ‘gmtime()’
     function, and *note OSError: 41a. on ‘gmtime()’ failure.  It’s
     common for this to be restricted to years in 1970 through 2038.

     To get an aware *note datetime: 1cc. object, call *note
     fromtimestamp(): 4f0.:

          datetime.fromtimestamp(timestamp, timezone.utc)

     On the POSIX compliant platforms, it is equivalent to the following
     expression:

          datetime(1970, 1, 1, tzinfo=timezone.utc) + timedelta(seconds=timestamp)

     except the latter formula always supports the full years range:
     between *note MINYEAR: 25e8. and *note MAXYEAR: 25e9. inclusive.

          Warning: Because naive ‘datetime’ objects are treated by many
          ‘datetime’ methods as local times, it is preferred to use
          aware datetimes to represent times in UTC. As such, the
          recommended way to create an object representing a specific
          timestamp in UTC is by calling
          ‘datetime.fromtimestamp(timestamp, tz=timezone.utc)’.

     Changed in version 3.3: Raise *note OverflowError: 888. instead of
     *note ValueError: 202. if the timestamp is out of the range of
     values supported by the platform C ‘gmtime()’ function.  Raise
     *note OSError: 41a. instead of ‘ValueError’ on ‘gmtime()’ failure.

     Deprecated since version 3.12: Use *note datetime.fromtimestamp():
     4f0. with *note UTC: 4f1. instead.

 -- Method: classmethod datetime.fromordinal (ordinal)

     Return the *note datetime: 1cc. corresponding to the proleptic
     Gregorian ordinal, where January 1 of year 1 has ordinal 1.  *note
     ValueError: 202. is raised unless ‘1 <= ordinal <=
     datetime.max.toordinal()’.  The hour, minute, second and
     microsecond of the result are all 0, and *note tzinfo: 25fa. is
     ‘None’.

 -- Method: classmethod datetime.combine (date, time,
          tzinfo=time.tzinfo)

     Return a new *note datetime: 1cc. object whose date components are
     equal to the given *note date: 1cd. object’s, and whose time
     components are equal to the given *note time: 1ce. object’s.  If
     the 'tzinfo' argument is provided, its value is used to set the
     *note tzinfo: 25fa. attribute of the result, otherwise the *note
     tzinfo: 25f2. attribute of the 'time' argument is used.  If the
     'date' argument is a ‘datetime’ object, its time components and
     ‘tzinfo’ attributes are ignored.

     For any *note datetime: 1cc. object ‘d’, ‘d ==
     datetime.combine(d.date(), d.time(), d.tzinfo)’.

     Changed in version 3.6: Added the 'tzinfo' argument.

 -- Method: classmethod datetime.fromisoformat (date_string)

     Return a *note datetime: 1cc. corresponding to a 'date_string' in
     any valid ISO 8601 format, with the following exceptions:

       1. Time zone offsets may have fractional seconds.

       2. The ‘T’ separator may be replaced by any single unicode
          character.

       3. Fractional hours and minutes are not supported.

       4. Reduced precision dates are not currently supported
          (‘YYYY-MM’, ‘YYYY’).

       5. Extended date representations are not currently supported
          (‘±YYYYYY-MM-DD’).

       6. Ordinal dates are not currently supported (‘YYYY-OOO’).

     Examples:

          >>> import datetime as dt
          >>> dt.datetime.fromisoformat('2011-11-04')
          datetime.datetime(2011, 11, 4, 0, 0)
          >>> dt.datetime.fromisoformat('20111104')
          datetime.datetime(2011, 11, 4, 0, 0)
          >>> dt.datetime.fromisoformat('2011-11-04T00:05:23')
          datetime.datetime(2011, 11, 4, 0, 5, 23)
          >>> dt.datetime.fromisoformat('2011-11-04T00:05:23Z')
          datetime.datetime(2011, 11, 4, 0, 5, 23, tzinfo=datetime.timezone.utc)
          >>> dt.datetime.fromisoformat('20111104T000523')
          datetime.datetime(2011, 11, 4, 0, 5, 23)
          >>> dt.datetime.fromisoformat('2011-W01-2T00:05:23.283')
          datetime.datetime(2011, 1, 4, 0, 5, 23, 283000)
          >>> dt.datetime.fromisoformat('2011-11-04 00:05:23.283')
          datetime.datetime(2011, 11, 4, 0, 5, 23, 283000)
          >>> dt.datetime.fromisoformat('2011-11-04 00:05:23.283+00:00')
          datetime.datetime(2011, 11, 4, 0, 5, 23, 283000, tzinfo=datetime.timezone.utc)
          >>> dt.datetime.fromisoformat('2011-11-04T00:05:23+04:00')
          datetime.datetime(2011, 11, 4, 0, 5, 23,
              tzinfo=datetime.timezone(datetime.timedelta(seconds=14400)))

     Added in version 3.7.

     Changed in version 3.11: Previously, this method only supported
     formats that could be emitted by *note date.isoformat(): 260f. or
     *note datetime.isoformat(): b48.

 -- Method: classmethod datetime.fromisocalendar (year, week, day)

     Return a *note datetime: 1cc. corresponding to the ISO calendar
     date specified by year, week and day.  The non-date components of
     the datetime are populated with their normal default values.  This
     is the inverse of the function *note datetime.isocalendar(): 8ff.

     Added in version 3.8.

 -- Method: classmethod datetime.strptime (date_string, format)

     Return a *note datetime: 1cc. corresponding to 'date_string',
     parsed according to 'format'.

     If 'format' does not contain microseconds or time zone information,
     this is equivalent to:

          datetime(*(time.strptime(date_string, format)[0:6]))

     *note ValueError: 202. is raised if the date_string and format
     can’t be parsed by *note time.strptime(): 147b. or if it returns a
     value which isn’t a time tuple.  See also *note strftime() and
     strptime() Behavior: 18f9. and *note datetime.fromisoformat(): 61a.

     Changed in version 3.13: If 'format' specifies a day of month
     without a year a *note DeprecationWarning: 1a5. is now emitted.
     This is to avoid a quadrennial leap year bug in code seeking to
     parse only a month and day as the default year used in absence of
     one in the format is not a leap year.  Such 'format' values may
     raise an error as of Python 3.15.  The workaround is to always
     include a year in your 'format'.  If parsing 'date_string' values
     that do not have a year, explicitly add a year that is a leap year
     before parsing:

          >>> import datetime as dt
          >>> date_string = "02/29"
          >>> when = dt.datetime.strptime(f"{date_string};1984", "%m/%d;%Y")  # Avoids leap year bug.
          >>> when.strftime("%B %d")
          'February 29'

Class attributes:

 -- Attribute: datetime.min

     The earliest representable *note datetime: 1cc, ‘datetime(MINYEAR,
     1, 1, tzinfo=None)’.

 -- Attribute: datetime.max

     The latest representable *note datetime: 1cc, ‘datetime(MAXYEAR,
     12, 31, 23, 59, 59, 999999, tzinfo=None)’.

 -- Attribute: datetime.resolution

     The smallest possible difference between non-equal *note datetime:
     1cc. objects, ‘timedelta(microseconds=1)’.

Instance attributes (read-only):

 -- Attribute: datetime.year

     Between *note MINYEAR: 25e8. and *note MAXYEAR: 25e9. inclusive.

 -- Attribute: datetime.month

     Between 1 and 12 inclusive.

 -- Attribute: datetime.day

     Between 1 and the number of days in the given month of the given
     year.

 -- Attribute: datetime.hour

     In ‘range(24)’.

 -- Attribute: datetime.minute

     In ‘range(60)’.

 -- Attribute: datetime.second

     In ‘range(60)’.

 -- Attribute: datetime.microsecond

     In ‘range(1000000)’.

 -- Attribute: datetime.tzinfo

     The object passed as the 'tzinfo' argument to the *note datetime:
     1cc. constructor, or ‘None’ if none was passed.

 -- Attribute: datetime.fold

     In ‘[0, 1]’.  Used to disambiguate wall times during a repeated
     interval.  (A repeated interval occurs when clocks are rolled back
     at the end of daylight saving time or when the UTC offset for the
     current zone is decreased for political reasons.)  The values 0 and
     1 represent, respectively, the earlier and later of the two moments
     with the same wall time representation.

     Added in version 3.6.

Supported operations:

Operation                                   Result
                                            
---------------------------------------------------------------------------------
                                            
‘datetime2 = datetime1 + timedelta’         (1)
                                            
                                            
‘datetime2 = datetime1 - timedelta’         (2)
                                            
                                            
‘timedelta = datetime1 - datetime2’         (3)
                                            
                                            
     ‘datetime1 == datetime2’               Equality comparison.  (4)
     ‘datetime1 != datetime2’               

     ‘datetime1 < datetime2’                Order comparison.  (5)
     ‘datetime1 > datetime2’                
     ‘datetime1 <= datetime2’
     ‘datetime1 >= datetime2’

  1. ‘datetime2’ is a duration of ‘timedelta’ removed from ‘datetime1’,
     moving forward in time if ‘timedelta.days > 0’, or backward if
     ‘timedelta.days < 0’.  The result has the same *note tzinfo: 25fa.
     attribute as the input datetime, and ‘datetime2 - datetime1 ==
     timedelta’ after.  *note OverflowError: 888. is raised if
     ‘datetime2.year’ would be smaller than *note MINYEAR: 25e8. or
     larger than *note MAXYEAR: 25e9.  Note that no time zone
     adjustments are done even if the input is an aware object.

  2. Computes the ‘datetime2’ such that ‘datetime2 + timedelta ==
     datetime1’.  As for addition, the result has the same *note tzinfo:
     25fa. attribute as the input datetime, and no time zone adjustments
     are done even if the input is aware.

  3. Subtraction of a *note datetime: 1cc. from a ‘datetime’ is defined
     only if both operands are naive, or if both are aware.  If one is
     aware and the other is naive, *note TypeError: 2c3. is raised.

     If both are naive, or both are aware and have the same *note
     tzinfo: 25fa. attribute, the ‘tzinfo’ attributes are ignored, and
     the result is a *note timedelta: 9da. object ‘t’ such that
     ‘datetime2 + t == datetime1’.  No time zone adjustments are done in
     this case.

     If both are aware and have different *note tzinfo: 25fa.
     attributes, ‘a-b’ acts as if ‘a’ and ‘b’ were first converted to
     naive UTC datetimes.  The result is ‘(a.replace(tzinfo=None) -
     a.utcoffset()) - (b.replace(tzinfo=None) - b.utcoffset())’ except
     that the implementation never overflows.

  4. *note datetime: 1cc. objects are equal if they represent the same
     date and time, taking into account the time zone.

     Naive and aware *note datetime: 1cc. objects are never equal.

     If both comparands are aware, and have the same ‘tzinfo’ attribute,
     the ‘tzinfo’ and *note fold: c78. attributes are ignored and the
     base datetimes are compared.  If both comparands are aware and have
     different *note tzinfo: 25fa. attributes, the comparison acts as
     comparands were first converted to UTC datetimes except that the
     implementation never overflows.  *note datetime: 1cc. instances in
     a repeated interval are never equal to ‘datetime’ instances in
     other time zone.

  5. 'datetime1' is considered less than 'datetime2' when 'datetime1'
     precedes 'datetime2' in time, taking into account the time zone.

     Order comparison between naive and aware *note datetime: 1cc.
     objects raises *note TypeError: 2c3.

     If both comparands are aware, and have the same ‘tzinfo’ attribute,
     the ‘tzinfo’ and *note fold: c78. attributes are ignored and the
     base datetimes are compared.  If both comparands are aware and have
     different *note tzinfo: 25fa. attributes, the comparison acts as
     comparands were first converted to UTC datetimes except that the
     implementation never overflows.

Changed in version 3.3: Equality comparisons between aware and naive
*note datetime: 1cc. instances don’t raise *note TypeError: 2c3.

Changed in version 3.13: Comparison between *note datetime: 1cc. object
and an instance of the *note date: 1cd. subclass that is not a
‘datetime’ subclass no longer converts the latter to ‘date’, ignoring
the time part and the time zone.  The default behavior can be changed by
overriding the special comparison methods in subclasses.

Instance methods:

 -- Method: datetime.date ()

     Return *note date: 1cd. object with same year, month and day.

 -- Method: datetime.time ()

     Return *note time: 1ce. object with same hour, minute, second,
     microsecond and fold.  *note tzinfo: 25fa. is ‘None’.  See also
     method *note timetz(): 261d.

     Changed in version 3.6: The fold value is copied to the returned
     *note time: 1ce. object.

 -- Method: datetime.timetz ()

     Return *note time: 1ce. object with same hour, minute, second,
     microsecond, fold, and tzinfo attributes.  See also method *note
     time(): ee.

     Changed in version 3.6: The fold value is copied to the returned
     *note time: 1ce. object.

 -- Method: datetime.replace (year=self.year, month=self.month,
          day=self.day, hour=self.hour, minute=self.minute,
          second=self.second, microsecond=self.microsecond,
          tzinfo=self.tzinfo, *, fold=0)

     Return a new *note datetime: 30. object with the same attributes,
     but with specified parameters updated.  Note that ‘tzinfo=None’ can
     be specified to create a naive datetime from an aware datetime with
     no conversion of date and time data.

     *note datetime: 1cc. objects are also supported by generic function
     *note copy.replace(): 151.

     Changed in version 3.6: Added the 'fold' parameter.

 -- Method: datetime.astimezone (tz=None)

     Return a *note datetime: 1cc. object with new *note tzinfo: 25fa.
     attribute 'tz', adjusting the date and time data so the result is
     the same UTC time as 'self', but in 'tz'’s local time.

     If provided, 'tz' must be an instance of a *note tzinfo: 5e1.
     subclass, and its *note utcoffset(): 261e. and *note dst(): 261f.
     methods must not return ‘None’.  If 'self' is naive, it is presumed
     to represent time in the system time zone.

     If called without arguments (or with ‘tz=None’) the system local
     time zone is assumed for the target time zone.  The ‘.tzinfo’
     attribute of the converted datetime instance will be set to an
     instance of *note timezone: 1103. with the zone name and offset
     obtained from the OS.

     If ‘self.tzinfo’ is 'tz', ‘self.astimezone(tz)’ is equal to 'self':
     no adjustment of date or time data is performed.  Else the result
     is local time in the time zone 'tz', representing the same UTC time
     as 'self': after ‘astz = dt.astimezone(tz)’, ‘astz -
     astz.utcoffset()’ will have the same date and time data as ‘dt -
     dt.utcoffset()’.

     If you merely want to attach a *note timezone: 1103. object 'tz' to
     a datetime 'dt' without adjustment of date and time data, use
     ‘dt.replace(tzinfo=tz)’.  If you merely want to remove the
     ‘timezone’ object from an aware datetime 'dt' without conversion of
     date and time data, use ‘dt.replace(tzinfo=None)’.

     Note that the default *note tzinfo.fromutc(): 2620. method can be
     overridden in a *note tzinfo: 5e1. subclass to affect the result
     returned by ‘astimezone()’.  Ignoring error cases, ‘astimezone()’
     acts like:

          def astimezone(self, tz):
              if self.tzinfo is tz:
                  return self
              # Convert self to UTC, and attach the new timezone object.
              utc = (self - self.utcoffset()).replace(tzinfo=tz)
              # Convert from UTC to tz's local time.
              return tz.fromutc(utc)

     Changed in version 3.3: 'tz' now can be omitted.

     Changed in version 3.6: The ‘astimezone()’ method can now be called
     on naive instances that are presumed to represent system local
     time.

 -- Method: datetime.utcoffset ()

     If *note tzinfo: 25fa. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.utcoffset(self)’, and raises an exception if the
     latter doesn’t return ‘None’ or a *note timedelta: 9da. object with
     magnitude less than one day.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

 -- Method: datetime.dst ()

     If *note tzinfo: 25fa. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.dst(self)’, and raises an exception if the latter
     doesn’t return ‘None’ or a *note timedelta: 9da. object with
     magnitude less than one day.

     Changed in version 3.7: The DST offset is not restricted to a whole
     number of minutes.

 -- Method: datetime.tzname ()

     If *note tzinfo: 25fa. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.tzname(self)’, raises an exception if the latter
     doesn’t return ‘None’ or a string object,

 -- Method: datetime.timetuple ()

     Return a *note time.struct_time: d11. such as returned by *note
     time.localtime(): 1548.

     ‘d.timetuple()’ is equivalent to:

          time.struct_time((d.year, d.month, d.day,
                            d.hour, d.minute, d.second,
                            d.weekday(), yday, dst))

     where ‘yday = d.toordinal() - date(d.year, 1, 1).toordinal() + 1’
     is the day number within the current year starting with 1 for
     January 1st.  The *note tm_isdst: 2623. flag of the result is set
     according to the *note dst(): 261f. method: *note tzinfo: 25fa. is
     ‘None’ or ‘dst()’ returns ‘None’, ‘tm_isdst’ is set to ‘-1’; else
     if ‘dst()’ returns a non-zero value, ‘tm_isdst’ is set to 1; else
     ‘tm_isdst’ is set to 0.

 -- Method: datetime.utctimetuple ()

     If *note datetime: 1cc. instance ‘d’ is naive, this is the same as
     ‘d.timetuple()’ except that *note tm_isdst: 2623. is forced to 0
     regardless of what ‘d.dst()’ returns.  DST is never in effect for a
     UTC time.

     If ‘d’ is aware, ‘d’ is normalized to UTC time, by subtracting
     ‘d.utcoffset()’, and a *note time.struct_time: d11. for the
     normalized time is returned.  ‘tm_isdst’ is forced to 0.  Note that
     an *note OverflowError: 888. may be raised if ‘d.year’ was
     ‘MINYEAR’ or ‘MAXYEAR’ and UTC adjustment spills over a year
     boundary.

          Warning: Because naive ‘datetime’ objects are treated by many
          ‘datetime’ methods as local times, it is preferred to use
          aware datetimes to represent times in UTC; as a result, using
          ‘datetime.utctimetuple()’ may give misleading results.  If you
          have a naive ‘datetime’ representing UTC, use
          ‘datetime.replace(tzinfo=timezone.utc)’ to make it aware, at
          which point you can use *note datetime.timetuple(): 2622.

 -- Method: datetime.toordinal ()

     Return the proleptic Gregorian ordinal of the date.  The same as
     ‘self.date().toordinal()’.

 -- Method: datetime.timestamp ()

     Return POSIX timestamp corresponding to the *note datetime: 1cc.
     instance.  The return value is a *note float: 2f7. similar to that
     returned by *note time.time(): 254.

     Naive *note datetime: 1cc. instances are assumed to represent local
     time and this method relies on the platform C ‘mktime()’ function
     to perform the conversion.  Since ‘datetime’ supports wider range
     of values than ‘mktime()’ on many platforms, this method may raise
     *note OverflowError: 888. or *note OSError: 41a. for times far in
     the past or far in the future.

     For aware *note datetime: 1cc. instances, the return value is
     computed as:

          (dt - datetime(1970, 1, 1, tzinfo=timezone.utc)).total_seconds()

     Added in version 3.3.

     Changed in version 3.6: The ‘timestamp()’ method uses the *note
     fold: c78. attribute to disambiguate the times during a repeated
     interval.

          Note: There is no method to obtain the POSIX timestamp
          directly from a naive *note datetime: 1cc. instance
          representing UTC time.  If your application uses this
          convention and your system time zone is not set to UTC, you
          can obtain the POSIX timestamp by supplying
          ‘tzinfo=timezone.utc’:

               timestamp = dt.replace(tzinfo=timezone.utc).timestamp()

          or by calculating the timestamp directly:

               timestamp = (dt - datetime(1970, 1, 1)) / timedelta(seconds=1)

 -- Method: datetime.weekday ()

     Return the day of the week as an integer, where Monday is 0 and
     Sunday is 6.  The same as ‘self.date().weekday()’.  See also *note
     isoweekday(): 2627.

 -- Method: datetime.isoweekday ()

     Return the day of the week as an integer, where Monday is 1 and
     Sunday is 7.  The same as ‘self.date().isoweekday()’.  See also
     *note weekday(): 2626, *note isocalendar(): 8ff.

 -- Method: datetime.isocalendar ()

     Return a *note named tuple: 651. with three components: ‘year’,
     ‘week’ and ‘weekday’.  The same as ‘self.date().isocalendar()’.

 -- Method: datetime.isoformat (sep='T', timespec='auto')

     Return a string representing the date and time in ISO 8601 format:

        - ‘YYYY-MM-DDTHH:MM:SS.ffffff’, if *note microsecond: 25f9. is
          not 0

        - ‘YYYY-MM-DDTHH:MM:SS’, if *note microsecond: 25f9. is 0

     If *note utcoffset(): 261e. does not return ‘None’, a string is
     appended, giving the UTC offset:

        - ‘YYYY-MM-DDTHH:MM:SS.ffffff+HH:MM[:SS[.ffffff]]’, if *note
          microsecond: 25f9. is not 0

        - ‘YYYY-MM-DDTHH:MM:SS+HH:MM[:SS[.ffffff]]’, if *note
          microsecond: 25f9. is 0

     Examples:

          >>> import datetime as dt
          >>> dt.datetime(2019, 5, 18, 15, 17, 8, 132263).isoformat()
          '2019-05-18T15:17:08.132263'
          >>> dt.datetime(2019, 5, 18, 15, 17, tzinfo=dt.timezone.utc).isoformat()
          '2019-05-18T15:17:00+00:00'

     The optional argument 'sep' (default ‘'T'’) is a one-character
     separator, placed between the date and time portions of the result.
     For example:

          >>> import datetime as dt
          >>> class TZ(dt.tzinfo):
          ...     """A time zone with an arbitrary, constant -06:39 offset."""
          ...     def utcoffset(self, when):
          ...         return dt.timedelta(hours=-6, minutes=-39)
          ...
          >>> dt.datetime(2002, 12, 25, tzinfo=TZ()).isoformat(' ')
          '2002-12-25 00:00:00-06:39'
          >>> dt.datetime(2009, 11, 27, microsecond=100, tzinfo=TZ()).isoformat()
          '2009-11-27T00:00:00.000100-06:39'

     The optional argument 'timespec' specifies the number of additional
     components of the time to include (the default is ‘'auto'’).  It
     can be one of the following:

        - ‘'auto'’: Same as ‘'seconds'’ if *note microsecond: 25f9. is
          0, same as ‘'microseconds'’ otherwise.

        - ‘'hours'’: Include the *note hour: 25f6. in the two-digit ‘HH’
          format.

        - ‘'minutes'’: Include *note hour: 25f6. and *note minute: 25f7.
          in ‘HH:MM’ format.

        - ‘'seconds'’: Include *note hour: 25f6, *note minute: 25f7, and
          *note second: 25f8. in ‘HH:MM:SS’ format.

        - ‘'milliseconds'’: Include full time, but truncate fractional
          second part to milliseconds.  ‘HH:MM:SS.sss’ format.

        - ‘'microseconds'’: Include full time in ‘HH:MM:SS.ffffff’
          format.

          Note: Excluded time components are truncated, not rounded.

     *note ValueError: 202. will be raised on an invalid 'timespec'
     argument:

          >>> import datetime as dt
          >>> dt.datetime.now().isoformat(timespec='minutes')
          '2002-12-25T00:00'
          >>> my_datetime = dt.datetime(2015, 1, 1, 12, 30, 59, 0)
          >>> my_datetime.isoformat(timespec='microseconds')
          '2015-01-01T12:30:59.000000'

     Changed in version 3.6: Added the 'timespec' parameter.

 -- Method: datetime.__str__ ()

     For a *note datetime: 1cc. instance ‘d’, ‘str(d)’ is equivalent to
     ‘d.isoformat(' ')’.

 -- Method: datetime.ctime ()

     Return a string representing the date and time:

          >>> import datetime as dt
          >>> dt.datetime(2002, 12, 4, 20, 30, 40).ctime()
          'Wed Dec  4 20:30:40 2002'

     The output string will 'not' include time zone information,
     regardless of whether the input is aware or naive.

     ‘d.ctime()’ is equivalent to:

          time.ctime(time.mktime(d.timetuple()))

     on platforms where the native C ‘ctime()’ function (which *note
     time.ctime(): 2612. invokes, but which ‘datetime.ctime()’ does not
     invoke) conforms to the C standard.

 -- Method: datetime.strftime (format)

     Return a string representing the date and time, controlled by an
     explicit format string.  See also *note strftime() and strptime()
     Behavior: 18f9. and *note datetime.isoformat(): b48.

 -- Method: datetime.__format__ (format)

     Same as *note datetime.strftime(): cb5.  This makes it possible to
     specify a format string for a *note datetime: 1cc. object in *note
     formatted string literals: 9b4. and when using *note str.format():
     624.  See also *note strftime() and strptime() Behavior: 18f9. and
     *note datetime.isoformat(): b48.

* Menu:

* Examples of Usage; datetime: Examples of Usage datetime.


File: python.info,  Node: Examples of Usage datetime,  Up: datetime Objects

5.8.1.11 Examples of Usage: ‘datetime’
......................................

Examples of working with *note datetime: 1cc. objects:

     >>> import datetime as dt

     >>> # Using datetime.combine()
     >>> d = dt.date(2005, 7, 14)
     >>> t = dt.time(12, 30)
     >>> dt.datetime.combine(d, t)
     datetime.datetime(2005, 7, 14, 12, 30)

     >>> # Using datetime.now()
     >>> dt.datetime.now()
     datetime.datetime(2007, 12, 6, 16, 29, 43, 79043)   # GMT +1
     >>> dt.datetime.now(dt.timezone.utc)
     datetime.datetime(2007, 12, 6, 15, 29, 43, 79060, tzinfo=datetime.timezone.utc)

     >>> # Using datetime.strptime()
     >>> my_datetime = dt.datetime.strptime("21/11/06 16:30", "%d/%m/%y %H:%M")
     >>> my_datetime
     datetime.datetime(2006, 11, 21, 16, 30)

     >>> # Using datetime.timetuple() to get tuple of all attributes
     >>> tt = my_datetime.timetuple()
     >>> for it in tt:
     ...     print(it)
     ...
     2006    # year
     11      # month
     21      # day
     16      # hour
     30      # minute
     0       # second
     1       # weekday (0 = Monday)
     325     # number of days since 1st January
     -1      # dst - method tzinfo.dst() returned None

     >>> # Date in ISO format
     >>> ic = my_datetime.isocalendar()
     >>> for it in ic:
     ...     print(it)
     ...
     2006    # ISO year
     47      # ISO week
     2       # ISO weekday

     >>> # Formatting a datetime
     >>> my_datetime.strftime("%A, %d. %B %Y %I:%M%p")
     'Tuesday, 21. November 2006 04:30PM'
     >>> 'The {1} is {0:%d}, the {2} is {0:%B}, the {3} is {0:%I:%M%p}.'.format(my_datetime, "day", "month", "time")
     'The day is 21, the month is November, the time is 04:30PM.'

The example below defines a *note tzinfo: 5e1. subclass capturing time
zone information for Kabul, Afghanistan, which used +4 UTC until 1945
and then +4:30 UTC thereafter:

     import datetime as dt

     class KabulTz(dt.tzinfo):
         # Kabul used +4 until 1945, when they moved to +4:30
         UTC_MOVE_DATE = dt.datetime(1944, 12, 31, 20, tzinfo=dt.timezone.utc)

         def utcoffset(self, when):
             if when.year < 1945:
                 return dt.timedelta(hours=4)
             elif (1945, 1, 1, 0, 0) <= when.timetuple()[:5] < (1945, 1, 1, 0, 30):
                 # An ambiguous ("imaginary") half-hour range representing
                 # a 'fold' in time due to the shift from +4 to +4:30.
                 # If when falls in the imaginary range, use fold to decide how
                 # to resolve. See PEP 495.
                 return dt.timedelta(hours=4, minutes=(30 if when.fold else 0))
             else:
                 return dt.timedelta(hours=4, minutes=30)

         def fromutc(self, when):
             # Follow same validations as in datetime.tzinfo
             if not isinstance(when, dt.datetime):
                 raise TypeError("fromutc() requires a datetime argument")
             if when.tzinfo is not self:
                 raise ValueError("when.tzinfo is not self")

             # A custom implementation is required for fromutc as
             # the input to this function is a datetime with utc values
             # but with a tzinfo set to self.
             # See datetime.astimezone or fromtimestamp.
             if when.replace(tzinfo=dt.timezone.utc) >= self.UTC_MOVE_DATE:
                 return when + dt.timedelta(hours=4, minutes=30)
             else:
                 return when + dt.timedelta(hours=4)

         def dst(self, when):
             # Kabul does not observe daylight saving time.
             return dt.timedelta(0)

         def tzname(self, when):
             if when >= self.UTC_MOVE_DATE:
                 return "+04:30"
             return "+04"

Usage of ‘KabulTz’ from above:

     >>> tz1 = KabulTz()

     >>> # Datetime before the change
     >>> dt1 = dt.datetime(1900, 11, 21, 16, 30, tzinfo=tz1)
     >>> print(dt1.utcoffset())
     4:00:00

     >>> # Datetime after the change
     >>> dt2 = dt.datetime(2006, 6, 14, 13, 0, tzinfo=tz1)
     >>> print(dt2.utcoffset())
     4:30:00

     >>> # Convert datetime to another time zone
     >>> dt3 = dt2.astimezone(dt.timezone.utc)
     >>> dt3
     datetime.datetime(2006, 6, 14, 8, 30, tzinfo=datetime.timezone.utc)
     >>> dt2
     datetime.datetime(2006, 6, 14, 13, 0, tzinfo=KabulTz())
     >>> dt2 == dt3
     True


File: python.info,  Node: time Objects,  Next: tzinfo Objects,  Prev: datetime Objects,  Up: datetime — Basic date and time types

5.8.1.12 ‘time’ Objects
.......................

A *note time: 1ce. object represents a (local) time of day, independent
of any particular day, and subject to adjustment via a *note tzinfo:
5e1. object.

 -- Class: datetime.time (hour=0, minute=0, second=0, microsecond=0,
          tzinfo=None, *, fold=0)

     All arguments are optional.  'tzinfo' may be ‘None’, or an instance
     of a *note tzinfo: 5e1. subclass.  The remaining arguments must be
     integers in the following ranges:

        * ‘0 <= hour < 24’,

        * ‘0 <= minute < 60’,

        * ‘0 <= second < 60’,

        * ‘0 <= microsecond < 1000000’,

        * ‘fold in [0, 1]’.

     If an argument outside those ranges is given, *note ValueError:
     202. is raised.  All default to 0 except 'tzinfo', which defaults
     to ‘None’.

Class attributes:

 -- Attribute: time.min

     The earliest representable *note time: 1ce, ‘time(0, 0, 0, 0)’.

 -- Attribute: time.max

     The latest representable *note time: 1ce, ‘time(23, 59, 59,
     999999)’.

 -- Attribute: time.resolution

     The smallest possible difference between non-equal *note time: 1ce.
     objects, ‘timedelta(microseconds=1)’, although note that arithmetic
     on ‘time’ objects is not supported.

Instance attributes (read-only):

 -- Attribute: time.hour

     In ‘range(24)’.

 -- Attribute: time.minute

     In ‘range(60)’.

 -- Attribute: time.second

     In ‘range(60)’.

 -- Attribute: time.microsecond

     In ‘range(1000000)’.

 -- Attribute: time.tzinfo

     The object passed as the tzinfo argument to the *note time: 1ce.
     constructor, or ‘None’ if none was passed.

 -- Attribute: time.fold

     In ‘[0, 1]’.  Used to disambiguate wall times during a repeated
     interval.  (A repeated interval occurs when clocks are rolled back
     at the end of daylight saving time or when the UTC offset for the
     current zone is decreased for political reasons.)  The values 0 and
     1 represent, respectively, the earlier and later of the two moments
     with the same wall time representation.

     Added in version 3.6.

*note time: 1ce. objects support equality and order comparisons, where
‘a’ is considered less than ‘b’ when ‘a’ precedes ‘b’ in time.

Naive and aware ‘time’ objects are never equal.  Order comparison
between naive and aware ‘time’ objects raises *note TypeError: 2c3.

If both comparands are aware, and have the same *note tzinfo: 25f2.
attribute, the ‘tzinfo’ and ‘fold’ attributes are ignored and the base
times are compared.  If both comparands are aware and have different
‘tzinfo’ attributes, the comparands are first adjusted by subtracting
their UTC offsets (obtained from ‘self.utcoffset()’).

Changed in version 3.3: Equality comparisons between aware and naive
*note time: 1ce. instances don’t raise *note TypeError: 2c3.

In Boolean contexts, a *note time: 1ce. object is always considered to
be true.

Changed in version 3.5: Before Python 3.5, a *note time: 1ce. object was
considered to be false if it represented midnight in UTC. This behavior
was considered obscure and error-prone and has been removed in Python
3.5.  See bpo-13936(1) for full details.

Other constructor:

 -- Method: classmethod time.fromisoformat (time_string)

     Return a *note time: 1ce. corresponding to a 'time_string' in any
     valid ISO 8601 format, with the following exceptions:

       1. Time zone offsets may have fractional seconds.

       2. The leading ‘T’, normally required in cases where there may be
          ambiguity between a date and a time, is not required.

       3. Fractional seconds may have any number of digits (anything
          beyond 6 will be truncated).

       4. Fractional hours and minutes are not supported.

     Examples:

          >>> import datetime as dt
          >>> dt.time.fromisoformat('04:23:01')
          datetime.time(4, 23, 1)
          >>> dt.time.fromisoformat('T04:23:01')
          datetime.time(4, 23, 1)
          >>> dt.time.fromisoformat('T042301')
          datetime.time(4, 23, 1)
          >>> dt.time.fromisoformat('04:23:01.000384')
          datetime.time(4, 23, 1, 384)
          >>> dt.time.fromisoformat('04:23:01,000384')
          datetime.time(4, 23, 1, 384)
          >>> dt.time.fromisoformat('04:23:01+04:00')
          datetime.time(4, 23, 1, tzinfo=datetime.timezone(datetime.timedelta(seconds=14400)))
          >>> dt.time.fromisoformat('04:23:01Z')
          datetime.time(4, 23, 1, tzinfo=datetime.timezone.utc)
          >>> dt.time.fromisoformat('04:23:01+00:00')
          datetime.time(4, 23, 1, tzinfo=datetime.timezone.utc)

     Added in version 3.7.

     Changed in version 3.11: Previously, this method only supported
     formats that could be emitted by *note time.isoformat(): 2631.

Instance methods:

 -- Method: time.replace (hour=self.hour, minute=self.minute,
          second=self.second, microsecond=self.microsecond,
          tzinfo=self.tzinfo, *, fold=0)

     Return a new *note time: 1ce. with the same values, but with
     specified parameters updated.  Note that ‘tzinfo=None’ can be
     specified to create a naive ‘time’ from an aware ‘time’, without
     conversion of the time data.

     *note time: 1ce. objects are also supported by generic function
     *note copy.replace(): 151.

     Changed in version 3.6: Added the 'fold' parameter.

 -- Method: time.isoformat (timespec='auto')

     Return a string representing the time in ISO 8601 format, one of:

        - ‘HH:MM:SS.ffffff’, if *note microsecond: 25f1. is not 0

        - ‘HH:MM:SS’, if *note microsecond: 25f1. is 0

        - ‘HH:MM:SS.ffffff+HH:MM[:SS[.ffffff]]’, if *note utcoffset():
          2632. does not return ‘None’

        - ‘HH:MM:SS+HH:MM[:SS[.ffffff]]’, if *note microsecond: 25f1. is
          0 and *note utcoffset(): 2632. does not return ‘None’

     The optional argument 'timespec' specifies the number of additional
     components of the time to include (the default is ‘'auto'’).  It
     can be one of the following:

        - ‘'auto'’: Same as ‘'seconds'’ if *note microsecond: 25f1. is
          0, same as ‘'microseconds'’ otherwise.

        - ‘'hours'’: Include the *note hour: 25ee. in the two-digit ‘HH’
          format.

        - ‘'minutes'’: Include *note hour: 25ee. and *note minute: 25ef.
          in ‘HH:MM’ format.

        - ‘'seconds'’: Include *note hour: 25ee, *note minute: 25ef, and
          *note second: 25f0. in ‘HH:MM:SS’ format.

        - ‘'milliseconds'’: Include full time, but truncate fractional
          second part to milliseconds.  ‘HH:MM:SS.sss’ format.

        - ‘'microseconds'’: Include full time in ‘HH:MM:SS.ffffff’
          format.

          Note: Excluded time components are truncated, not rounded.

     *note ValueError: 202. will be raised on an invalid 'timespec'
     argument.

     Example:

          >>> import datetime as dt
          >>> dt.time(hour=12, minute=34, second=56, microsecond=123456).isoformat(timespec='minutes')
          '12:34'
          >>> my_time = dt.time(hour=12, minute=34, second=56, microsecond=0)
          >>> my_time.isoformat(timespec='microseconds')
          '12:34:56.000000'
          >>> my_time.isoformat(timespec='auto')
          '12:34:56'

     Changed in version 3.6: Added the 'timespec' parameter.

 -- Method: time.__str__ ()

     For a time ‘t’, ‘str(t)’ is equivalent to ‘t.isoformat()’.

 -- Method: time.strftime (format)

     Return a string representing the time, controlled by an explicit
     format string.  See also *note strftime() and strptime() Behavior:
     18f9. and *note time.isoformat(): 2631.

 -- Method: time.__format__ (format)

     Same as *note time.strftime(): 189b.  This makes it possible to
     specify a format string for a *note time: 1ce. object in *note
     formatted string literals: 9b4. and when using *note str.format():
     624.  See also *note strftime() and strptime() Behavior: 18f9. and
     *note time.isoformat(): 2631.

 -- Method: time.utcoffset ()

     If *note tzinfo: 25f2. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.utcoffset(None)’, and raises an exception if the
     latter doesn’t return ‘None’ or a *note timedelta: 9da. object with
     magnitude less than one day.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

 -- Method: time.dst ()

     If *note tzinfo: 25f2. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.dst(None)’, and raises an exception if the latter
     doesn’t return ‘None’, or a *note timedelta: 9da. object with
     magnitude less than one day.

     Changed in version 3.7: The DST offset is not restricted to a whole
     number of minutes.

 -- Method: time.tzname ()

     If *note tzinfo: 25f2. is ‘None’, returns ‘None’, else returns
     ‘self.tzinfo.tzname(None)’, or raises an exception if the latter
     doesn’t return ‘None’ or a string object.

* Menu:

* Examples of Usage; time: Examples of Usage time.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=13936


File: python.info,  Node: Examples of Usage time,  Up: time Objects

5.8.1.13 Examples of Usage: ‘time’
..................................

Examples of working with a *note time: 1ce. object:

     >>> import datetime as dt
     >>> class TZ1(dt.tzinfo):
     ...     def utcoffset(self, when):
     ...         return dt.timedelta(hours=1)
     ...     def dst(self, when):
     ...         return dt.timedelta(0)
     ...     def tzname(self, when):
     ...         return "+01:00"
     ...     def  __repr__(self):
     ...         return f"{self.__class__.__name__}()"
     ...
     >>> t = dt.time(12, 10, 30, tzinfo=TZ1())
     >>> t
     datetime.time(12, 10, 30, tzinfo=TZ1())
     >>> t.isoformat()
     '12:10:30+01:00'
     >>> t.dst()
     datetime.timedelta(0)
     >>> t.tzname()
     '+01:00'
     >>> t.strftime("%H:%M:%S %Z")
     '12:10:30 +01:00'
     >>> 'The {} is {:%H:%M}.'.format("time", t)
     'The time is 12:10.'


File: python.info,  Node: tzinfo Objects,  Next: timezone Objects,  Prev: time Objects,  Up: datetime — Basic date and time types

5.8.1.14 ‘tzinfo’ Objects
.........................

 -- Class: datetime.tzinfo

     This is an abstract base class, meaning that this class should not
     be instantiated directly.  Define a subclass of ‘tzinfo’ to capture
     information about a particular time zone.

     An instance of (a concrete subclass of) ‘tzinfo’ can be passed to
     the constructors for *note datetime: 1cc. and *note time: 1ce.
     objects.  The latter objects view their attributes as being in
     local time, and the ‘tzinfo’ object supports methods revealing
     offset of local time from UTC, the name of the time zone, and DST
     offset, all relative to a date or time object passed to them.

     You need to derive a concrete subclass, and (at least) supply
     implementations of the standard ‘tzinfo’ methods needed by the
     *note datetime: 1cc. methods you use.  The ‘datetime’ module
     provides *note timezone: 1103, a simple concrete subclass of
     ‘tzinfo’ which can represent time zones with fixed offset from UTC
     such as UTC itself or North American EST and EDT.

     Special requirement for pickling: A ‘tzinfo’ subclass must have an
     *note __init__(): 6b3. method that can be called with no arguments,
     otherwise it can be pickled but possibly not unpickled again.  This
     is a technical requirement that may be relaxed in the future.

     A concrete subclass of ‘tzinfo’ may need to implement the following
     methods.  Exactly which methods are needed depends on the uses made
     of aware ‘datetime’ objects.  If in doubt, simply implement all of
     them.

 -- Method: tzinfo.utcoffset (dt)

     Return offset of local time from UTC, as a *note timedelta: 9da.
     object that is positive east of UTC. If local time is west of UTC,
     this should be negative.

     This represents the 'total' offset from UTC; for example, if a
     *note tzinfo: 5e1. object represents both time zone and DST
     adjustments, ‘utcoffset()’ should return their sum.  If the UTC
     offset isn’t known, return ‘None’.  Else the value returned must be
     a *note timedelta: 9da. object strictly between
     ‘-timedelta(hours=24)’ and ‘timedelta(hours=24)’ (the magnitude of
     the offset must be less than one day).  Most implementations of
     ‘utcoffset()’ will probably look like one of these two:

          return CONSTANT                 # fixed-offset class
          return CONSTANT + self.dst(dt)  # daylight-aware class

     If ‘utcoffset()’ does not return ‘None’, *note dst(): 263b. should
     not return ‘None’ either.

     The default implementation of ‘utcoffset()’ raises *note
     NotImplementedError: 228.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

 -- Method: tzinfo.dst (dt)

     Return the daylight saving time (DST) adjustment, as a *note
     timedelta: 9da. object or ‘None’ if DST information isn’t known.

     Return ‘timedelta(0)’ if DST is not in effect.  If DST is in
     effect, return the offset as a *note timedelta: 9da. object (see
     *note utcoffset(): 263a. for details).  Note that DST offset, if
     applicable, has already been added to the UTC offset returned by
     ‘utcoffset()’, so there’s no need to consult ‘dst()’ unless you’re
     interested in obtaining DST info separately.  For example, *note
     datetime.timetuple(): 2622. calls its *note tzinfo: 25fa.
     attribute’s ‘dst()’ method to determine how the *note tm_isdst:
     2623. flag should be set, and *note tzinfo.fromutc(): 2620. calls
     ‘dst()’ to account for DST changes when crossing time zones.

     An instance 'tz' of a *note tzinfo: 5e1. subclass that models both
     standard and daylight times must be consistent in this sense:

     ‘tz.utcoffset(dt) - tz.dst(dt)’

     must return the same result for every *note datetime: 1cc. 'dt'
     with ‘dt.tzinfo == tz’.  For sane ‘tzinfo’ subclasses, this
     expression yields the time zone’s “standard offset”, which should
     not depend on the date or the time, but only on geographic
     location.  The implementation of *note datetime.astimezone(): 9db.
     relies on this, but cannot detect violations; it’s the programmer’s
     responsibility to ensure it.  If a ‘tzinfo’ subclass cannot
     guarantee this, it may be able to override the default
     implementation of *note tzinfo.fromutc(): 2620. to work correctly
     with ‘astimezone()’ regardless.

     Most implementations of ‘dst()’ will probably look like one of
     these two:

          import datetime as dt

          def dst(self, when):
              # a fixed-offset class:  doesn't account for DST
              return dt.timedelta(0)

     or:

          import datetime as dt

          def dst(self, when):
              # Code to set dston and dstoff to the time zone's DST
              # transition times based on the input when.year, and expressed
              # in standard local time.

              if dston <= when.replace(tzinfo=None) < dstoff:
                  return dt.timedelta(hours=1)
              else:
                  return dt.timedelta(0)

     The default implementation of ‘dst()’ raises *note
     NotImplementedError: 228.

     Changed in version 3.7: The DST offset is not restricted to a whole
     number of minutes.

 -- Method: tzinfo.tzname (dt)

     Return the time zone name corresponding to the *note datetime: 1cc.
     object 'dt', as a string.  Nothing about string names is defined by
     the ‘datetime’ module, and there’s no requirement that it mean
     anything in particular.  For example, ‘"GMT"’, ‘"UTC"’, ‘"-500"’,
     ‘"-5:00"’, ‘"EDT"’, ‘"US/Eastern"’, ‘"America/New York"’ are all
     valid replies.  Return ‘None’ if a string name isn’t known.  Note
     that this is a method rather than a fixed string primarily because
     some *note tzinfo: 5e1. subclasses will wish to return different
     names depending on the specific value of 'dt' passed, especially if
     the ‘tzinfo’ class is accounting for daylight time.

     The default implementation of ‘tzname()’ raises *note
     NotImplementedError: 228.

These methods are called by a *note datetime: 1cc. or *note time: 1ce.
object, in response to their methods of the same names.  A ‘datetime’
object passes itself as the argument, and a ‘time’ object passes ‘None’
as the argument.  A *note tzinfo: 5e1. subclass’s methods should
therefore be prepared to accept a 'dt' argument of ‘None’, or of class
‘datetime’.

When ‘None’ is passed, it’s up to the class designer to decide the best
response.  For example, returning ‘None’ is appropriate if the class
wishes to say that time objects don’t participate in the *note tzinfo:
5e1. protocols.  It may be more useful for ‘utcoffset(None)’ to return
the standard UTC offset, as there is no other convention for discovering
the standard offset.

When a *note datetime: 1cc. object is passed in response to a ‘datetime’
method, ‘dt.tzinfo’ is the same object as 'self'.  *note tzinfo: 5e1.
methods can rely on this, unless user code calls ‘tzinfo’ methods
directly.  The intent is that the ‘tzinfo’ methods interpret 'dt' as
being in local time, and not need worry about objects in other time
zones.

There is one more *note tzinfo: 5e1. method that a subclass may wish to
override:

 -- Method: tzinfo.fromutc (dt)

     This is called from the default *note datetime.astimezone(): 9db.
     implementation.  When called from that, ‘dt.tzinfo’ is 'self', and
     'dt'’s date and time data are to be viewed as expressing a UTC
     time.  The purpose of ‘fromutc()’ is to adjust the date and time
     data, returning an equivalent datetime in 'self'’s local time.

     Most *note tzinfo: 5e1. subclasses should be able to inherit the
     default ‘fromutc()’ implementation without problems.  It’s strong
     enough to handle fixed-offset time zones, and time zones accounting
     for both standard and daylight time, and the latter even if the DST
     transition times differ in different years.  An example of a time
     zone the default ‘fromutc()’ implementation may not handle
     correctly in all cases is one where the standard offset (from UTC)
     depends on the specific date and time passed, which can happen for
     political reasons.  The default implementations of *note
     astimezone(): 9db. and ‘fromutc()’ may not produce the result you
     want if the result is one of the hours straddling the moment the
     standard offset changes.

     Skipping code for error cases, the default ‘fromutc()’
     implementation acts like:

          import datetime as dt

          def fromutc(self, when):
              # raise ValueError error if when.tzinfo is not self
              dtoff = when.utcoffset()
              dtdst = when.dst()
              # raise ValueError if dtoff is None or dtdst is None
              delta = dtoff - dtdst  # this is self's standard offset
              if delta:
                  when += delta   # convert to standard local time
                  dtdst = when.dst()
                  # raise ValueError if dtdst is None
              if dtdst:
                  return when + dtdst
              else:
                  return when

In the following ‘tzinfo_examples.py’ file there are some examples of
*note tzinfo: 5e1. classes:

     import datetime as dt

     # A class capturing the platform's idea of local time.
     # (May result in wrong values on historical times in
     #  timezones where UTC offset and/or the DST rules had
     #  changed in the past.)
     import time

     ZERO = dt.timedelta(0)
     HOUR = dt.timedelta(hours=1)
     SECOND = dt.timedelta(seconds=1)

     STDOFFSET = dt.timedelta(seconds=-time.timezone)
     if time.daylight:
         DSTOFFSET = dt.timedelta(seconds=-time.altzone)
     else:
         DSTOFFSET = STDOFFSET

     DSTDIFF = DSTOFFSET - STDOFFSET


     class LocalTimezone(dt.tzinfo):

         def fromutc(self, when):
             assert when.tzinfo is self
             stamp = (when - dt.datetime(1970, 1, 1, tzinfo=self)) // SECOND
             args = time.localtime(stamp)[:6]
             dst_diff = DSTDIFF // SECOND
             # Detect fold
             fold = (args == time.localtime(stamp - dst_diff))
             return dt.datetime(*args, microsecond=when.microsecond,
                                tzinfo=self, fold=fold)

         def utcoffset(self, when):
             if self._isdst(when):
                 return DSTOFFSET
             else:
                 return STDOFFSET

         def dst(self, when):
             if self._isdst(when):
                 return DSTDIFF
             else:
                 return ZERO

         def tzname(self, when):
             return time.tzname[self._isdst(when)]

         def _isdst(self, when):
             tt = (when.year, when.month, when.day,
                   when.hour, when.minute, when.second,
                   when.weekday(), 0, 0)
             stamp = time.mktime(tt)
             tt = time.localtime(stamp)
             return tt.tm_isdst > 0


     Local = LocalTimezone()


     # A complete implementation of current DST rules for major US time zones.

     def first_sunday_on_or_after(when):
         days_to_go = 6 - when.weekday()
         if days_to_go:
             when += dt.timedelta(days_to_go)
         return when


     # US DST Rules
     #
     # This is a simplified (i.e., wrong for a few cases) set of rules for US
     # DST start and end times. For a complete and up-to-date set of DST rules
     # and timezone definitions, visit the Olson Database (or try pytz):
     # http://www.twinsun.com/tz/tz-link.htm
     # https://sourceforge.net/projects/pytz/ (might not be up-to-date)
     #
     # In the US, since 2007, DST starts at 2am (standard time) on the second
     # Sunday in March, which is the first Sunday on or after Mar 8.
     DSTSTART_2007 = dt.datetime(1, 3, 8, 2)
     # and ends at 2am (DST time) on the first Sunday of Nov.
     DSTEND_2007 = dt.datetime(1, 11, 1, 2)
     # From 1987 to 2006, DST used to start at 2am (standard time) on the first
     # Sunday in April and to end at 2am (DST time) on the last
     # Sunday of October, which is the first Sunday on or after Oct 25.
     DSTSTART_1987_2006 = dt.datetime(1, 4, 1, 2)
     DSTEND_1987_2006 = dt.datetime(1, 10, 25, 2)
     # From 1967 to 1986, DST used to start at 2am (standard time) on the last
     # Sunday in April (the one on or after April 24) and to end at 2am (DST time)
     # on the last Sunday of October, which is the first Sunday
     # on or after Oct 25.
     DSTSTART_1967_1986 = dt.datetime(1, 4, 24, 2)
     DSTEND_1967_1986 = DSTEND_1987_2006


     def us_dst_range(year):
         # Find start and end times for US DST. For years before 1967, return
         # start = end for no DST.
         if 2006 < year:
             dststart, dstend = DSTSTART_2007, DSTEND_2007
         elif 1986 < year < 2007:
             dststart, dstend = DSTSTART_1987_2006, DSTEND_1987_2006
         elif 1966 < year < 1987:
             dststart, dstend = DSTSTART_1967_1986, DSTEND_1967_1986
         else:
             return (dt.datetime(year, 1, 1), ) * 2

         start = first_sunday_on_or_after(dststart.replace(year=year))
         end = first_sunday_on_or_after(dstend.replace(year=year))
         return start, end


     class USTimeZone(dt.tzinfo):

         def __init__(self, hours, reprname, stdname, dstname):
             self.stdoffset = dt.timedelta(hours=hours)
             self.reprname = reprname
             self.stdname = stdname
             self.dstname = dstname

         def __repr__(self):
             return self.reprname

         def tzname(self, when):
             if self.dst(when):
                 return self.dstname
             else:
                 return self.stdname

         def utcoffset(self, when):
             return self.stdoffset + self.dst(when)

         def dst(self, when):
             if when is None or when.tzinfo is None:
                 # An exception may be sensible here, in one or both cases.
                 # It depends on how you want to treat them.  The default
                 # fromutc() implementation (called by the default astimezone()
                 # implementation) passes a datetime with when.tzinfo is self.
                 return ZERO
             assert when.tzinfo is self
             start, end = us_dst_range(when.year)
             # Can't compare naive to aware objects, so strip the timezone from
             # when first.
             when = when.replace(tzinfo=None)
             if start + HOUR <= when < end - HOUR:
                 # DST is in effect.
                 return HOUR
             if end - HOUR <= when < end:
                 # Fold (an ambiguous hour): use when.fold to disambiguate.
                 return ZERO if when.fold else HOUR
             if start <= when < start + HOUR:
                 # Gap (a non-existent hour): reverse the fold rule.
                 return HOUR if when.fold else ZERO
             # DST is off.
             return ZERO

         def fromutc(self, when):
             assert when.tzinfo is self
             start, end = us_dst_range(when.year)
             start = start.replace(tzinfo=self)
             end = end.replace(tzinfo=self)
             std_time = when + self.stdoffset
             dst_time = std_time + HOUR
             if end <= dst_time < end + HOUR:
                 # Repeated hour
                 return std_time.replace(fold=1)
             if std_time < start or dst_time >= end:
                 # Standard time
                 return std_time
             if start <= std_time < end - HOUR:
                 # Daylight saving time
                 return dst_time


     Eastern  = USTimeZone(-5, "Eastern",  "EST", "EDT")
     Central  = USTimeZone(-6, "Central",  "CST", "CDT")
     Mountain = USTimeZone(-7, "Mountain", "MST", "MDT")
     Pacific  = USTimeZone(-8, "Pacific",  "PST", "PDT")

Note that there are unavoidable subtleties twice per year in a *note
tzinfo: 5e1. subclass accounting for both standard and daylight time, at
the DST transition points.  For concreteness, consider US Eastern (UTC
-0500), where EDT begins the minute after 1:59 (EST) on the second
Sunday in March, and ends the minute after 1:59 (EDT) on the first
Sunday in November:

       UTC   3:MM  4:MM  5:MM  6:MM  7:MM  8:MM
       EST  22:MM 23:MM  0:MM  1:MM  2:MM  3:MM
       EDT  23:MM  0:MM  1:MM  2:MM  3:MM  4:MM

     start  22:MM 23:MM  0:MM  1:MM  3:MM  4:MM

       end  23:MM  0:MM  1:MM  1:MM  2:MM  3:MM

When DST starts (the “start” line), the local wall clock leaps from 1:59
to 3:00.  A wall time of the form 2:MM doesn’t really make sense on that
day, so ‘astimezone(Eastern)’ won’t deliver a result with ‘hour == 2’ on
the day DST begins.  For example, at the Spring forward transition of
2016, we get:

     >>> import datetime as dt
     >>> from tzinfo_examples import HOUR, Eastern
     >>> u0 = dt.datetime(2016, 3, 13, 5, tzinfo=dt.timezone.utc)
     >>> for i in range(4):
     ...     u = u0 + i*HOUR
     ...     t = u.astimezone(Eastern)
     ...     print(u.time(), 'UTC =', t.time(), t.tzname())
     ...
     05:00:00 UTC = 00:00:00 EST
     06:00:00 UTC = 01:00:00 EST
     07:00:00 UTC = 03:00:00 EDT
     08:00:00 UTC = 04:00:00 EDT

When DST ends (the “end” line), there’s a potentially worse problem:
there’s an hour that can’t be spelled unambiguously in local wall time:
the last hour of daylight time.  In Eastern, that’s times of the form
5:MM UTC on the day daylight time ends.  The local wall clock leaps from
1:59 (daylight time) back to 1:00 (standard time) again.  Local times of
the form 1:MM are ambiguous.  *note astimezone(): 9db. mimics the local
clock’s behavior by mapping two adjacent UTC hours into the same local
hour then.  In the Eastern example, UTC times of the form 5:MM and 6:MM
both map to 1:MM when converted to Eastern, but earlier times have the
*note fold: c78. attribute set to 0 and the later times have it set to
1.  For example, at the Fall back transition of 2016, we get:

     >>> import datetime as dt
     >>> from tzinfo_examples import HOUR, Eastern
     >>> u0 = dt.datetime(2016, 11, 6, 4, tzinfo=dt.timezone.utc)
     >>> for i in range(4):
     ...     u = u0 + i*HOUR
     ...     t = u.astimezone(Eastern)
     ...     print(u.time(), 'UTC =', t.time(), t.tzname(), t.fold)
     ...
     04:00:00 UTC = 00:00:00 EDT 0
     05:00:00 UTC = 01:00:00 EDT 0
     06:00:00 UTC = 01:00:00 EST 1
     07:00:00 UTC = 02:00:00 EST 0

Note that the *note datetime: 1cc. instances that differ only by the
value of the *note fold: c78. attribute are considered equal in
comparisons.

Applications that can’t bear wall-time ambiguities should explicitly
check the value of the *note fold: c78. attribute or avoid using hybrid
*note tzinfo: 5e1. subclasses; there are no ambiguities when using *note
timezone: 1103, or any other fixed-offset ‘tzinfo’ subclass (such as a
class representing only EST (fixed offset -5 hours), or only EDT (fixed
offset -4 hours)).

See also
........

     *note zoneinfo: 134.

          The ‘datetime’ module has a basic *note timezone: 1103. class
          (for handling arbitrary fixed offsets from UTC) and its *note
          timezone.utc: 617. attribute (a UTC ‘timezone’ instance).

          ‘zoneinfo’ brings the 'IANA time zone database' (also known as
          the Olson database) to Python, and its usage is recommended.

IANA time zone database(1)

     The Time Zone Database (often called tz, tzdata or zoneinfo)
     contains code and data that represent the history of local time for
     many representative locations around the globe.  It is updated
     periodically to reflect changes made by political bodies to time
     zone boundaries, UTC offsets, and daylight-saving rules.

   ---------- Footnotes ----------

   (1) https://www.iana.org/time-zones


File: python.info,  Node: timezone Objects,  Next: strftime and strptime Behavior,  Prev: tzinfo Objects,  Up: datetime — Basic date and time types

5.8.1.15 ‘timezone’ Objects
...........................

The *note timezone: 1103. class is a subclass of *note tzinfo: 5e1, each
instance of which represents a time zone defined by a fixed offset from
UTC.

Objects of this class cannot be used to represent time zone information
in the locations where different offsets are used in different days of
the year or where historical changes have been made to civil time.

 -- Class: datetime.timezone (offset, name=None)

     The 'offset' argument must be specified as a *note timedelta: 9da.
     object representing the difference between the local time and UTC.
     It must be strictly between ‘-timedelta(hours=24)’ and
     ‘timedelta(hours=24)’, otherwise *note ValueError: 202. is raised.

     The 'name' argument is optional.  If specified it must be a string
     that will be used as the value returned by the *note
     datetime.tzname(): 2621. method.

     Added in version 3.2.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

 -- Method: timezone.utcoffset (dt)

     Return the fixed value specified when the *note timezone: 1103.
     instance is constructed.

     The 'dt' argument is ignored.  The return value is a *note
     timedelta: 9da. instance equal to the difference between the local
     time and UTC.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

 -- Method: timezone.tzname (dt)

     Return the fixed value specified when the *note timezone: 1103.
     instance is constructed.

     If 'name' is not provided in the constructor, the name returned by
     ‘tzname(dt)’ is generated from the value of the ‘offset’ as
     follows.  If 'offset' is ‘timedelta(0)’, the name is “UTC”,
     otherwise it is a string in the format ‘UTC±HH:MM’, where ± is the
     sign of ‘offset’, HH and MM are two digits of ‘offset.hours’ and
     ‘offset.minutes’ respectively.

     Changed in version 3.6: Name generated from ‘offset=timedelta(0)’
     is now plain ‘'UTC'’, not ‘'UTC+00:00'’.

 -- Method: timezone.dst (dt)

     Always returns ‘None’.

 -- Method: timezone.fromutc (dt)

     Return ‘dt + offset’.  The 'dt' argument must be an aware *note
     datetime: 1cc. instance, with ‘tzinfo’ set to ‘self’.

Class attributes:

 -- Attribute: timezone.utc

     The UTC time zone, ‘timezone(timedelta(0))’.


File: python.info,  Node: strftime and strptime Behavior,  Prev: timezone Objects,  Up: datetime — Basic date and time types

5.8.1.16 ‘strftime()’ and ‘strptime()’ Behavior
...............................................

*note date: 1cd, *note datetime: 1cc, and *note time: 1ce. objects all
support a ‘strftime(format)’ method, to create a string representing the
time under the control of an explicit format string.

Conversely, the *note datetime.strptime(): 1714. class method creates a
*note datetime: 1cc. object from a string representing a date and time
and a corresponding format string.

The table below provides a high-level comparison of *note strftime():
cb5. versus *note strptime(): 1714.:

                     ‘strftime’                                                   ‘strptime’
                                                                                  
---------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  
Usage                Convert object to a string according to a given format       Parse a string into a *note datetime: 1cc. object given a corresponding format
                                                                                  
                                                                                  
Type of method       Instance method                                              Class method
                                                                                  
                                                                                  
Method of            *note date: 1cd.; *note datetime: 1cc.; *note time: 1ce.     *note datetime: 1cc.
                                                                                  
                                                                                  
Signature            ‘strftime(format)’                                           ‘strptime(date_string, format)’
                                                                                  

* Menu:

* strftime() and strptime() Format Codes: strftime and strptime Format Codes.
* Technical Detail::


File: python.info,  Node: strftime and strptime Format Codes,  Next: Technical Detail,  Up: strftime and strptime Behavior

5.8.1.17 ‘strftime()’ and ‘strptime()’ Format Codes
...................................................

These methods accept format codes that can be used to parse and format
dates:

     >>> import datetime as dt
     >>> dt.datetime.strptime('31/01/22 23:59:59.999999',
     ...                      '%d/%m/%y %H:%M:%S.%f')
     datetime.datetime(2022, 1, 31, 23, 59, 59, 999999)
     >>> _.strftime('%a %d %b %Y, %I:%M%p')
     'Mon 31 Jan 2022, 11:59PM'

The following is a list of all the format codes that the 1989 C standard
requires, and these work on all platforms with a standard C
implementation.

Directive       Meaning                              Example                      Notes
                                                                                  
----------------------------------------------------------------------------------------------
                                                                                  
‘%a’            Weekday as locale’s abbreviated           Sun, Mon, …, Sat (en_US);(1)
                name.                                     So, Mo, …, Sa (de_DE)   
                                                     
                                                                                  
‘%A’            Weekday as locale’s full name.            Sunday, Monday, …, Saturday (en_US);(1)
                                                          Sonntag, Montag, …, Samstag (de_DE)
                                                     
                                                                                  
‘%w’            Weekday as a decimal number, where   0, 1, …, 6
                0 is Sunday and 6 is Saturday.       
                
                                                                                  
‘%d’            Day of the month as a zero-padded    01, 02, …, 31                (9)
                decimal number.                                                   
                
                                                                                  
‘%b’            Month as locale’s abbreviated             Jan, Feb, …, Dec (en_US);(1)
                name.                                     Jan, Feb, …, Dez (de_DE)
                                                     
                                                                                  
‘%B’            Month as locale’s full name.              January, February, …, December (en_US);(1)
                                                          Januar, Februar, …, Dezember (de_DE)
                                                     
                                                                                  
‘%m’            Month as a zero-padded decimal       01, 02, …, 12                (9)
                number.                                                           
                
                                                                                  
‘%y’            Year without century as a            00, 01, …, 99                (9)
                zero-padded decimal number.                                       
                
                                                                                  
‘%Y’            Year with century as a decimal       0001, 0002, …, 2013, 2014,   (2)
                number.                              …, 9998, 9999                
                                                     
                                                                                  
‘%H’            Hour (24-hour clock) as a            00, 01, …, 23                (9)
                zero-padded decimal number.                                       
                
                                                                                  
‘%I’            Hour (12-hour clock) as a            01, 02, …, 12                (9)
                zero-padded decimal number.                                       
                
                                                                                  
‘%p’            Locale’s equivalent of either AM          AM, PM (en_US);         (1), (3)
                or PM.                                    am, pm (de_DE)          
                                                     
                                                                                  
‘%M’            Minute as a zero-padded decimal      00, 01, …, 59                (9)
                number.                                                           
                
                                                                                  
‘%S’            Second as a zero-padded decimal      00, 01, …, 59                (4), (9)
                number.                                                           
                
                                                                                  
‘%f’            Microsecond as a decimal number,     000000, 000001, …, 999999    (5)
                zero-padded to 6 digits.                                          
                
                                                                                  
‘%z’            UTC offset in the form               (empty), +0000, -0400,       (6)
                ‘±HHMM[SS[.ffffff]]’ (empty string   +1030, +063415,              
                if the object is naive).             -030712.345216
                                                     
                                                                                  
‘%Z’            Time zone name (empty string if      (empty), UTC, GMT            (6)
                the object is naive).                                             
                
                                                                                  
‘%j’            Day of the year as a zero-padded     001, 002, …, 366             (9)
                decimal number.                                                   
                
                                                                                  
‘%U’            Week number of the year (Sunday as   00, 01, …, 53                (7), (9)
                the first day of the week) as a                                   
                zero-padded decimal number.  All
                days in a new year preceding the
                first Sunday are considered to be
                in week 0.
                
                                                                                  
‘%W’            Week number of the year (Monday as   00, 01, …, 53                (7), (9)
                the first day of the week) as a                                   
                zero-padded decimal number.  All
                days in a new year preceding the
                first Monday are considered to be
                in week 0.
                
                                                                                  
‘%c’            Locale’s appropriate date and time        Tue Aug 16 21:30:00 1988 (en_US);(1)
                representation.                           Di 16 Aug 21:30:00 1988 (de_DE)
                                                     
                                                                                  
‘%x’            Locale’s appropriate date                 08/16/88 (None);        (1)
                representation.                           08/16/1988 (en_US);     
                                                          16.08.1988 (de_DE)
                                                     
                                                                                  
‘%X’            Locale’s appropriate time                 21:30:00 (en_US);       (1)
                representation.                           21:30:00 (de_DE)        
                                                     
                                                                                  
‘%%’            A literal ‘'%'’ character.           %
                                                     

Several additional directives not required by the C89 standard are
included for convenience.  These parameters all correspond to ISO 8601
date values.

Directive       Meaning                              Example                      Notes
                                                                                  
----------------------------------------------------------------------------------------------
                                                                                  
‘%G’            ISO 8601 year with century           0001, 0002, …, 2013, 2014,   (8)
                representing the year that           …, 9998, 9999                
                contains the greater part of the     
                ISO week (‘%V’).
                
                                                                                  
‘%u’            ISO 8601 weekday as a decimal        1, 2, …, 7
                number where 1 is Monday.            
                
                                                                                  
‘%V’            ISO 8601 week as a decimal number    01, 02, …, 53                (8), (9)
                with Monday as the first day of                                   
                the week.  Week 01 is the week
                containing Jan 4.
                
                                                                                  
‘%:z’           UTC offset in the form               (empty), +00:00, -04:00,     (6)
                ‘±HH:MM[:SS[.ffffff]]’ (empty        +10:30, +06:34:15,           
                string if the object is naive).      -03:07:12.345216
                                                     

These may not be available on all platforms when used with the *note
strftime(): cb5. method.  The ISO 8601 year and ISO 8601 week directives
are not interchangeable with the year and week number directives above.
Calling *note strptime(): 1714. with incomplete or ambiguous ISO 8601
directives will raise a *note ValueError: 202.

The full set of format codes supported varies across platforms, because
Python calls the platform C library’s ‘strftime()’ function, and
platform variations are common.  To see the full set of format codes
supported on your platform, consult the ‘strftime(3)(1)’ documentation.
There are also differences between platforms in handling of unsupported
format specifiers.

Added in version 3.6: ‘%G’, ‘%u’ and ‘%V’ were added.

Added in version 3.12: ‘%:z’ was added.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/strftime(3)


File: python.info,  Node: Technical Detail,  Prev: strftime and strptime Format Codes,  Up: strftime and strptime Behavior

5.8.1.18 Technical Detail
.........................

Broadly speaking, ‘d.strftime(fmt)’ acts like the *note time: ee.
module’s ‘time.strftime(fmt, d.timetuple())’ although not all objects
support a *note timetuple(): 260b. method.

For the *note datetime.strptime(): 1714. class method, the default value
is ‘1900-01-01T00:00:00.000’: any components not specified in the format
string will be pulled from the default value.

     Note: Format strings without separators can be ambiguous for
     parsing.  For example, with ‘%Y%m%d’, the string ‘2026111’ may be
     parsed either as ‘2026-11-01’ or as ‘2026-01-11’.  Use separators
     to ensure the input is parsed as intended.

     Note: When used to parse partial dates lacking a year, *note
     datetime.strptime(): 1714. will raise when encountering February 29
     because the default year of 1900 is 'not' a leap year.  Always add
     a default leap year to partial date strings before parsing.

     >>> import datetime as dt
     >>> value = "2/29"
     >>> dt.datetime.strptime(value, "%m/%d")
     Traceback (most recent call last):
     ...
     ValueError: day 29 must be in range 1..28 for month 2 in year 1900
     >>> dt.datetime.strptime(f"1904 {value}", "%Y %m/%d")
     datetime.datetime(1904, 2, 29, 0, 0)

Using ‘datetime.strptime(date_string, format)’ is equivalent to:

     datetime(*(time.strptime(date_string, format)[0:6]))

except when the format includes sub-second components or time zone
offset information, which are supported in ‘datetime.strptime’ but are
discarded by ‘time.strptime’.

For *note time: 1ce. objects, the format codes for year, month, and day
should not be used, as ‘time’ objects have no such values.  If they’re
used anyway, 1900 is substituted for the year, and 1 for the month and
day.

For *note date: 1cd. objects, the format codes for hours, minutes,
seconds, and microseconds should not be used, as ‘date’ objects have no
such values.  If they’re used anyway, 0 is substituted for them.

For the same reason, handling of format strings containing Unicode code
points that can’t be represented in the charset of the current locale is
also platform-dependent.  On some platforms such code points are
preserved intact in the output, while on others ‘strftime’ may raise
*note UnicodeError: 12eb. or return an empty string instead.

Notes:

  1. Because the format depends on the current locale, care should be
     taken when making assumptions about the output value.  Field
     orderings will vary (for example, “month/day/year” versus
     “day/month/year”), and the output may contain non-ASCII characters.

  2. The *note strptime(): 1714. method can parse years in the full [1,
     9999] range, but years < 1000 must be zero-filled to 4-digit width.

     Changed in version 3.2: In previous versions, *note strftime():
     cb5. method was restricted to years >= 1900.

     Changed in version 3.3: In version 3.2, *note strftime(): cb5.
     method was restricted to years >= 1000.

  3. When used with the *note strptime(): 1714. method, the ‘%p’
     directive only affects the output hour field if the ‘%I’ directive
     is used to parse the hour.

  4. Unlike the *note time: ee. module, the ‘datetime’ module does not
     support leap seconds.

  5. When used with the *note strptime(): 1714. method, the ‘%f’
     directive accepts from one to six digits and zero pads on the
     right.  ‘%f’ is an extension to the set of format characters in the
     C standard (but implemented separately in datetime objects, and
     therefore always available).

  6. For a naive object, the ‘%z’, ‘%:z’ and ‘%Z’ format codes are
     replaced by empty strings.

     For an aware object:

     ‘%z’

          *note utcoffset(): 261e. is transformed into a string of the
          form ‘±HHMM[SS[.ffffff]]’, where ‘HH’ is a 2-digit string
          giving the number of UTC offset hours, ‘MM’ is a 2-digit
          string giving the number of UTC offset minutes, ‘SS’ is a
          2-digit string giving the number of UTC offset seconds and
          ‘ffffff’ is a 6-digit string giving the number of UTC offset
          microseconds.  The ‘ffffff’ part is omitted when the offset is
          a whole number of seconds and both the ‘ffffff’ and the ‘SS’
          part is omitted when the offset is a whole number of minutes.
          For example, if ‘utcoffset()’ returns ‘timedelta(hours=-3,
          minutes=-30)’, ‘%z’ is replaced with the string ‘'-0330'’.

     Changed in version 3.7: The UTC offset is not restricted to a whole
     number of minutes.

     Changed in version 3.7: When the ‘%z’ directive is provided to the
     *note strptime(): 1714. method, the UTC offsets can have a colon as
     a separator between hours, minutes and seconds.  For example,
     ‘'+01:00:00'’ will be parsed as an offset of one hour.  In
     addition, providing ‘'Z'’ is identical to ‘'+00:00'’.

     ‘%:z’

          Behaves exactly as ‘%z’, but has a colon separator added
          between hours, minutes and seconds.

     ‘%Z’

          In *note strftime(): cb5, ‘%Z’ is replaced by an empty string
          if *note tzname(): 2621. returns ‘None’; otherwise ‘%Z’ is
          replaced by the returned value, which must be a string.

          *note strptime(): 1714. only accepts certain values for ‘%Z’:

            1. any value in ‘time.tzname’ for your machine’s locale

            2. the hard-coded values ‘UTC’ and ‘GMT’

          So someone living in Japan may have ‘JST’, ‘UTC’, and ‘GMT’ as
          valid values, but probably not ‘EST’.  It will raise
          ‘ValueError’ for invalid values.

     Changed in version 3.2: When the ‘%z’ directive is provided to the
     *note strptime(): 1714. method, an aware *note datetime: 1cc.
     object will be produced.  The ‘tzinfo’ of the result will be set to
     a *note timezone: 1103. instance.

  7. When used with the *note strptime(): 1714. method, ‘%U’ and ‘%W’
     are only used in calculations when the day of the week and the
     calendar year (‘%Y’) are specified.

  8. Similar to ‘%U’ and ‘%W’, ‘%V’ is only used in calculations when
     the day of the week and the ISO year (‘%G’) are specified in a
     *note strptime(): 1714. format string.  Also note that ‘%G’ and
     ‘%Y’ are not interchangeable.

  9. When used with the *note strptime(): 1714. method, the leading zero
     is optional for formats ‘%d’, ‘%m’, ‘%H’, ‘%I’, ‘%M’, ‘%S’, ‘%j’,
     ‘%U’, ‘%W’, and ‘%V’.  Format ‘%y’ does require a leading zero.

  10. When parsing a month and day using *note strptime(): 1714, always
     include a year in the format.  If the value you need to parse lacks
     a year, append an explicit dummy leap year.  Otherwise your code
     will raise an exception when it encounters leap day because the
     default year used by the parser (1900) is not a leap year.  Users
     run into that bug every leap year.

          >>> month_day = "02/29"
          >>> dt.datetime.strptime(f"{month_day};1984", "%m/%d;%Y")  # No leap year bug.
          datetime.datetime(1984, 2, 29, 0, 0)

     Deprecated since version 3.13, will be removed in version 3.15:
     *note strptime(): 1714. calls using a format string containing a
     day of month without a year now emit a *note DeprecationWarning:
     1a5.  In 3.15 or later we may change this into an error or change
     the default year to a leap year.  See gh-70647(1).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/70647


File: python.info,  Node: zoneinfo — IANA time zone support,  Next: calendar — General calendar-related functions,  Prev: datetime — Basic date and time types,  Up: Data Types

5.8.2 ‘zoneinfo’ — IANA time zone support
-----------------------------------------

Added in version 3.9.

'Source code:' Lib/zoneinfo(1)

__________________________________________________________________

The ‘zoneinfo’ module provides a concrete time zone implementation to
support the IANA time zone database as originally specified in PEP
615(2).  By default, ‘zoneinfo’ uses the system’s time zone data if
available; if no system time zone data is available, the library will
fall back to using the first-party tzdata(3) package available on PyPI.

See also
........

Module: *note datetime: 30.

     Provides the *note time: 1ce. and *note datetime: 1cc. types with
     which the *note ZoneInfo: 8e8. class is designed to be used.

Package tzdata(4)

     First-party package maintained by the CPython core developers to
     supply time zone data via PyPI.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

* Menu:

* Using ZoneInfo::
* Data sources::
* The ZoneInfo class::
* Functions: Functions<3>.
* Globals::
* Exceptions and warnings::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/zoneinfo

   (2) https://peps.python.org/pep-0615/

   (3) https://pypi.org/project/tzdata/

   (4) https://pypi.org/project/tzdata/


File: python.info,  Node: Using ZoneInfo,  Next: Data sources,  Up: zoneinfo — IANA time zone support

5.8.2.1 Using ‘ZoneInfo’
........................

*note ZoneInfo: 8e8. is a concrete implementation of the *note
datetime.tzinfo: 5e1. abstract base class, and is intended to be
attached to ‘tzinfo’, either via the constructor, the *note
datetime.replace: 151a. method or *note datetime.astimezone: 9db.:

     >>> from zoneinfo import ZoneInfo
     >>> import datetime as dt

     >>> when = dt.datetime(2020, 10, 31, 12, tzinfo=ZoneInfo("America/Los_Angeles"))
     >>> print(when)
     2020-10-31 12:00:00-07:00

     >>> when.tzname()
     'PDT'

Datetimes constructed in this way are compatible with datetime
arithmetic and handle daylight saving time transitions with no further
intervention:

     >>> when_add = when + dt.timedelta(days=1)

     >>> print(when_add)
     2020-11-01 12:00:00-08:00

     >>> when_add.tzname()
     'PST'

These time zones also support the *note fold: c78. attribute introduced
in PEP 495(1).  During offset transitions which induce ambiguous times
(such as a daylight saving time to standard time transition), the offset
from 'before' the transition is used when ‘fold=0’, and the offset
'after' the transition is used when ‘fold=1’, for example:

     >>> when = dt.datetime(2020, 11, 1, 1, tzinfo=ZoneInfo("America/Los_Angeles"))
     >>> print(when)
     2020-11-01 01:00:00-07:00

     >>> print(when.replace(fold=1))
     2020-11-01 01:00:00-08:00

When converting from another time zone, the fold will be set to the
correct value:

     >>> LOS_ANGELES = ZoneInfo("America/Los_Angeles")
     >>> when_utc = dt.datetime(2020, 11, 1, 8, tzinfo=dt.timezone.utc)

     >>> # Before the PDT -> PST transition
     >>> print(when_utc.astimezone(LOS_ANGELES))
     2020-11-01 01:00:00-07:00

     >>> # After the PDT -> PST transition
     >>> print((when_utc + dt.timedelta(hours=1)).astimezone(LOS_ANGELES))
     2020-11-01 01:00:00-08:00

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0495/


File: python.info,  Node: Data sources,  Next: The ZoneInfo class,  Prev: Using ZoneInfo,  Up: zoneinfo — IANA time zone support

5.8.2.2 Data sources
....................

The ‘zoneinfo’ module does not directly provide time zone data, and
instead pulls time zone information from the system time zone database
or the first-party PyPI package tzdata(1), if available.  Some systems,
including notably Windows systems, do not have an IANA database
available, and so for projects targeting cross-platform compatibility
that require time zone data, it is recommended to declare a dependency
on tzdata.  If neither system data nor tzdata are available, all calls
to *note ZoneInfo: 8e8. will raise *note ZoneInfoNotFoundError: 1631.

* Menu:

* Configuring the data sources::

   ---------- Footnotes ----------

   (1) https://pypi.org/project/tzdata/


File: python.info,  Node: Configuring the data sources,  Up: Data sources

5.8.2.3 Configuring the data sources
....................................

When ‘ZoneInfo(key)’ is called, the constructor first searches the
directories specified in *note TZPATH: 1f17. for a file matching ‘key’,
and on failure looks for a match in the tzdata package.  This behavior
can be configured in three ways:

  1. The default *note TZPATH: 1f17. when not otherwise specified can be
     configured at *note compile time: 1f18.

  2. *note TZPATH: 1f17. can be configured using *note an environment
     variable: 264d.

  3. At *note runtime: 264e, the search path can be manipulated using
     the *note reset_tzpath(): 1616. function.

* Menu:

* Compile-time configuration::
* Environment configuration::
* Runtime configuration::


File: python.info,  Node: Compile-time configuration,  Next: Environment configuration,  Up: Configuring the data sources

5.8.2.4 Compile-time configuration
..................................

The default *note TZPATH: 1f17. includes several common deployment
locations for the time zone database (except on Windows, where there are
no “well-known” locations for time zone data).  On POSIX systems,
downstream distributors and those building Python from source who know
where their system time zone data is deployed may change the default
time zone path by specifying the compile-time option ‘TZPATH’ (or, more
likely, the *note configure flag -with-tzpath: 1f16.), which should be a
string delimited by *note os.pathsep: 1eec.

On all platforms, the configured value is available as the ‘TZPATH’ key
in *note sysconfig.get_config_var(): 1068.


File: python.info,  Node: Environment configuration,  Next: Runtime configuration,  Prev: Compile-time configuration,  Up: Configuring the data sources

5.8.2.5 Environment configuration
.................................

When initializing *note TZPATH: 1f17. (either at import time or whenever
*note reset_tzpath(): 1616. is called with no arguments), the ‘zoneinfo’
module will use the environment variable ‘PYTHONTZPATH’, if it exists,
to set the search path.

 -- Environment Variable: PYTHONTZPATH

     This is an *note os.pathsep: 1eec.-separated string containing the
     time zone search path to use.  It must consist of only absolute
     rather than relative paths.  Relative components specified in
     ‘PYTHONTZPATH’ will not be used, but otherwise the behavior when a
     relative path is specified is implementation-defined; CPython will
     raise *note InvalidTZPathWarning: 2652, but other implementations
     are free to silently ignore the erroneous component or raise an
     exception.

To set the system to ignore the system data and use the tzdata package
instead, set ‘PYTHONTZPATH=""’.


File: python.info,  Node: Runtime configuration,  Prev: Environment configuration,  Up: Configuring the data sources

5.8.2.6 Runtime configuration
.............................

The TZ search path can also be configured at runtime using the *note
reset_tzpath(): 1616. function.  This is generally not an advisable
operation, though it is reasonable to use it in test functions that
require the use of a specific time zone path (or require disabling
access to the system time zones).


File: python.info,  Node: The ZoneInfo class,  Next: Functions<3>,  Prev: Data sources,  Up: zoneinfo — IANA time zone support

5.8.2.7 The ‘ZoneInfo’ class
............................

 -- Class: zoneinfo.ZoneInfo (key)

     A concrete *note datetime.tzinfo: 5e1. subclass that represents an
     IANA time zone specified by the string ‘key’.  Calls to the primary
     constructor will always return objects that compare identically;
     put another way, barring cache invalidation via *note
     ZoneInfo.clear_cache(): 15b5, for all values of ‘key’, the
     following assertion will always be true:

          a = ZoneInfo(key)
          b = ZoneInfo(key)
          assert a is b

     ‘key’ must be in the form of a relative, normalized POSIX path,
     with no up-level references.  The constructor will raise *note
     ValueError: 202. if a non-conforming key is passed.

     If no file matching ‘key’ is found, the constructor will raise
     *note ZoneInfoNotFoundError: 1631.

The ‘ZoneInfo’ class has two alternate constructors:

 -- Method: classmethod ZoneInfo.from_file (file_obj, /, key=None)

     Constructs a ‘ZoneInfo’ object from a file-like object returning
     bytes (e.g.  a file opened in binary mode or an *note io.BytesIO:
     ed8. object).  Unlike the primary constructor, this always
     constructs a new object.

     The ‘key’ parameter sets the name of the zone for the purposes of
     *note __str__(): 620. and *note __repr__(): 61f.

     Objects created via this constructor cannot be pickled (see *note
     pickling: 2655.).

     *note ValueError: 202. is raised if the data read from 'file_obj'
     is not a valid TZif file.

 -- Method: classmethod ZoneInfo.no_cache (key)

     An alternate constructor that bypasses the constructor’s cache.  It
     is identical to the primary constructor, but returns a new object
     on each call.  This is most likely to be useful for testing or
     demonstration purposes, but it can also be used to create a system
     with a different cache invalidation strategy.

     Objects created via this constructor will also bypass the cache of
     a deserializing process when unpickled.

          Caution: Using this constructor may change the semantics of
          your datetimes in surprising ways, only use it if you know
          that you need to.

The following class methods are also available:

 -- Method: classmethod ZoneInfo.clear_cache (*, only_keys=None)

     A method for invalidating the cache on the ‘ZoneInfo’ class.  If no
     arguments are passed, all caches are invalidated and the next call
     to the primary constructor for each key will return a new instance.

     If an iterable of key names is passed to the ‘only_keys’ parameter,
     only the specified keys will be removed from the cache.  Keys
     passed to ‘only_keys’ but not found in the cache are ignored.

          Warning: Invoking this function may change the semantics of
          datetimes using ‘ZoneInfo’ in surprising ways; this modifies
          module state and thus may have wide-ranging effects.  Only use
          it if you know that you need to.

The class has one attribute:

 -- Attribute: ZoneInfo.key

     This is a read-only *note attribute: 2658. that returns the value
     of ‘key’ passed to the constructor, which should be a lookup key in
     the IANA time zone database (e.g.  ‘America/New_York’,
     ‘Europe/Paris’ or ‘Asia/Tokyo’).

     For zones constructed from file without specifying a ‘key’
     parameter, this will be set to ‘None’.

          Note: Although it is a somewhat common practice to expose
          these to end users, these values are designed to be primary
          keys for representing the relevant zones and not necessarily
          user-facing elements.  Projects like CLDR (the Unicode Common
          Locale Data Repository) can be used to get more user-friendly
          strings from these keys.

* Menu:

* String representations::
* Pickle serialization::


File: python.info,  Node: String representations,  Next: Pickle serialization,  Up: The ZoneInfo class

5.8.2.8 String representations
..............................

The string representation returned when calling *note str: 44f. on a
*note ZoneInfo: 8e8. object defaults to using the *note ZoneInfo.key:
2657. attribute (see the note on usage in the attribute documentation):

     >>> zone = ZoneInfo("Pacific/Kwajalein")
     >>> str(zone)
     'Pacific/Kwajalein'

     >>> when = dt.datetime(2020, 4, 1, 3, 15, tzinfo=zone)
     >>> f"{when.isoformat()} [{when.tzinfo}]"
     '2020-04-01T03:15:00+12:00 [Pacific/Kwajalein]'

For objects constructed from a file without specifying a ‘key’
parameter, ‘str’ falls back to calling *note repr(): 803.  ‘ZoneInfo’’s
‘repr’ is implementation-defined and not necessarily stable between
versions, but it is guaranteed not to be a valid ‘ZoneInfo’ key.


File: python.info,  Node: Pickle serialization,  Prev: String representations,  Up: The ZoneInfo class

5.8.2.9 Pickle serialization
............................

Rather than serializing all transition data, ‘ZoneInfo’ objects are
serialized by key, and ‘ZoneInfo’ objects constructed from files (even
those with a value for ‘key’ specified) cannot be pickled.

The behavior of a ‘ZoneInfo’ file depends on how it was constructed:

  1. ‘ZoneInfo(key)’: When constructed with the primary constructor, a
     ‘ZoneInfo’ object is serialized by key, and when deserialized, the
     deserializing process uses the primary and thus it is expected that
     these are the same object as other references to the same time
     zone.  For example, if ‘europe_berlin_pkl’ is a string containing a
     pickle constructed from ‘ZoneInfo("Europe/Berlin")’, one would
     expect the following behavior:

          >>> a = ZoneInfo("Europe/Berlin")
          >>> b = pickle.loads(europe_berlin_pkl)
          >>> a is b
          True

  2. ‘ZoneInfo.no_cache(key)’: When constructed from the cache-bypassing
     constructor, the ‘ZoneInfo’ object is also serialized by key, but
     when deserialized, the deserializing process uses the cache
     bypassing constructor.  If ‘europe_berlin_pkl_nc’ is a string
     containing a pickle constructed from
     ‘ZoneInfo.no_cache("Europe/Berlin")’, one would expect the
     following behavior:

          >>> a = ZoneInfo("Europe/Berlin")
          >>> b = pickle.loads(europe_berlin_pkl_nc)
          >>> a is b
          False

  3. ‘ZoneInfo.from_file(file_obj, /, key=None)’: When constructed from
     a file, the ‘ZoneInfo’ object raises an exception on pickling.  If
     an end user wants to pickle a ‘ZoneInfo’ constructed from a file,
     it is recommended that they use a wrapper type or a custom
     serialization function: either serializing by key or storing the
     contents of the file object and serializing that.

This method of serialization requires that the time zone data for the
required key be available on both the serializing and deserializing
side, similar to the way that references to classes and functions are
expected to exist in both the serializing and deserializing
environments.  It also means that no guarantees are made about the
consistency of results when unpickling a ‘ZoneInfo’ pickled in an
environment with a different version of the time zone data.


File: python.info,  Node: Functions<3>,  Next: Globals,  Prev: The ZoneInfo class,  Up: zoneinfo — IANA time zone support

5.8.2.10 Functions
..................

 -- Function: zoneinfo.available_timezones ()

     Get a set containing all the valid keys for IANA time zones
     available anywhere on the time zone path.  This is recalculated on
     every call to the function.

     This function only includes canonical zone names and does not
     include “special” zones such as those under the ‘posix/’ and
     ‘right/’ directories, or the ‘posixrules’ zone.

          Caution: This function may open a large number of files, as
          the best way to determine if a file on the time zone path is a
          valid time zone is to read the “magic string” at the
          beginning.

          Note: These values are not designed to be exposed to
          end-users; for user facing elements, applications should use
          something like CLDR (the Unicode Common Locale Data
          Repository) to get more user-friendly strings.  See also the
          cautionary note on *note ZoneInfo.key: 2657.

 -- Function: zoneinfo.reset_tzpath (to=None)

     Sets or resets the time zone search path (*note TZPATH: 1f17.) for
     the module.  When called with no arguments, ‘TZPATH’ is set to the
     default value.

     Calling ‘reset_tzpath’ will not invalidate the *note ZoneInfo: 8e8.
     cache, and so calls to the primary ‘ZoneInfo’ constructor will only
     use the new ‘TZPATH’ in the case of a cache miss.

     The ‘to’ parameter must be a *note sequence: 4f4. of strings or
     *note os.PathLike: c72. and not a string, all of which must be
     absolute paths.  *note ValueError: 202. will be raised if something
     other than an absolute path is passed.


File: python.info,  Node: Globals,  Next: Exceptions and warnings,  Prev: Functions<3>,  Up: zoneinfo — IANA time zone support

5.8.2.11 Globals
................

 -- Data: zoneinfo.TZPATH

     A read-only sequence representing the time zone search path – when
     constructing a ‘ZoneInfo’ from a key, the key is joined to each
     entry in the ‘TZPATH’, and the first file found is used.

     ‘TZPATH’ may contain only absolute paths, never relative paths,
     regardless of how it is configured.

     The object that ‘zoneinfo.TZPATH’ points to may change in response
     to a call to *note reset_tzpath(): 1616, so it is recommended to
     use ‘zoneinfo.TZPATH’ rather than importing ‘TZPATH’ from
     ‘zoneinfo’ or assigning a long-lived variable to ‘zoneinfo.TZPATH’.

     For more information on configuring the time zone search path, see
     *note Configuring the data sources: 264c.


File: python.info,  Node: Exceptions and warnings,  Prev: Globals,  Up: zoneinfo — IANA time zone support

5.8.2.12 Exceptions and warnings
................................

 -- Exception: zoneinfo.ZoneInfoNotFoundError

     Raised when construction of a *note ZoneInfo: 8e8. object fails
     because the specified key could not be found on the system.  This
     is a subclass of *note KeyError: 345.

 -- Exception: zoneinfo.InvalidTZPathWarning

     Raised when *note PYTHONTZPATH: 2651. contains an invalid component
     that will be filtered out, such as a relative path.


File: python.info,  Node: calendar — General calendar-related functions,  Next: collections — Container datatypes,  Prev: zoneinfo — IANA time zone support,  Up: Data Types

5.8.3 ‘calendar’ — General calendar-related functions
-----------------------------------------------------

'Source code:' Lib/calendar.py(1)

__________________________________________________________________

This module allows you to output calendars like the Unix ‘cal’ program,
and provides additional useful functions related to the calendar.  By
default, these calendars have Monday as the first day of the week, and
Sunday as the last (the European convention).  Use *note
setfirstweekday(): 2661. to set the first day of the week to Sunday (6)
or to any other weekday.  Parameters that specify dates are given as
integers.  For related functionality, see also the *note datetime: 30.
and *note time: ee. modules.

The functions and classes defined in this module use an idealized
calendar, the current Gregorian calendar extended indefinitely in both
directions.  This matches the definition of the “proleptic Gregorian”
calendar in Dershowitz and Reingold’s book “Calendrical Calculations”,
where it’s the base calendar for all computations.  Zero and negative
years are interpreted as prescribed by the ISO 8601 standard.  Year 0 is
1 BC, year -1 is 2 BC, and so on.

 -- Class: calendar.Calendar (firstweekday=0)

     Creates a ‘Calendar’ object.  'firstweekday' is an integer
     specifying the first day of the week.  *note MONDAY: 2663. is ‘0’
     (the default), *note SUNDAY: 2664. is ‘6’.

     A ‘Calendar’ object provides several methods that can be used for
     preparing the calendar data for formatting.  This class doesn’t do
     any formatting itself.  This is the job of subclasses.

     ‘Calendar’ instances have the following methods and attributes:

      -- Attribute: firstweekday

          The first weekday as an integer (0–6).

          This property can also be set and read using *note
          setfirstweekday(): 2666. and *note getfirstweekday(): 2667.
          respectively.

      -- Method: getfirstweekday ()

          Return an *note int: 257. for the current first weekday (0–6).

          Identical to reading the *note firstweekday: 2665. property.

      -- Method: setfirstweekday (firstweekday)

          Set the first weekday to 'firstweekday', passed as an *note
          int: 257. (0–6)

          Identical to setting the *note firstweekday: 2665. property.

      -- Method: iterweekdays ()

          Return an iterator for the week day numbers that will be used
          for one week.  The first value from the iterator will be the
          same as the value of the *note firstweekday: 2665. property.

      -- Method: itermonthdates (year, month)

          Return an iterator for the month 'month' (1–12) in the year
          'year'.  This iterator will return all days (as *note
          datetime.date: 1cd. objects) for the month and all days before
          the start of the month or after the end of the month that are
          required to get a complete week.

      -- Method: itermonthdays (year, month)

          Return an iterator for the month 'month' in the year 'year'
          similar to *note itermonthdates(): c39, but not restricted by
          the *note datetime.date: 1cd. range.  Days returned will
          simply be day of the month numbers.  For the days outside of
          the specified month, the day number is ‘0’.

      -- Method: itermonthdays2 (year, month)

          Return an iterator for the month 'month' in the year 'year'
          similar to *note itermonthdates(): c39, but not restricted by
          the *note datetime.date: 1cd. range.  Days returned will be
          tuples consisting of a day of the month number and a week day
          number.

      -- Method: itermonthdays3 (year, month)

          Return an iterator for the month 'month' in the year 'year'
          similar to *note itermonthdates(): c39, but not restricted by
          the *note datetime.date: 1cd. range.  Days returned will be
          tuples consisting of a year, a month and a day of the month
          numbers.

          Added in version 3.7.

      -- Method: itermonthdays4 (year, month)

          Return an iterator for the month 'month' in the year 'year'
          similar to *note itermonthdates(): c39, but not restricted by
          the *note datetime.date: 1cd. range.  Days returned will be
          tuples consisting of a year, a month, a day of the month, and
          a day of the week numbers.

          Added in version 3.7.

      -- Method: monthdatescalendar (year, month)

          Return a list of the weeks in the month 'month' of the 'year'
          as full weeks.  Weeks are lists of seven *note datetime.date:
          1cd. objects.

      -- Method: monthdays2calendar (year, month)

          Return a list of the weeks in the month 'month' of the 'year'
          as full weeks.  Weeks are lists of seven tuples of day numbers
          and weekday numbers.

      -- Method: monthdayscalendar (year, month)

          Return a list of the weeks in the month 'month' of the 'year'
          as full weeks.  Weeks are lists of seven day numbers.

      -- Method: yeardatescalendar (year, width=3)

          Return the data for the specified year ready for formatting.
          The return value is a list of month rows.  Each month row
          contains up to 'width' months (defaulting to 3).  Each month
          contains between 4 and 6 weeks and each week contains 1–7
          days.  Days are *note datetime.date: 1cd. objects.

      -- Method: yeardays2calendar (year, width=3)

          Return the data for the specified year ready for formatting
          (similar to *note yeardatescalendar(): 266e.).  Entries in the
          week lists are tuples of day numbers and weekday numbers.  Day
          numbers outside this month are zero.

      -- Method: yeardayscalendar (year, width=3)

          Return the data for the specified year ready for formatting
          (similar to *note yeardatescalendar(): 266e.).  Entries in the
          week lists are day numbers.  Day numbers outside this month
          are zero.

 -- Class: calendar.TextCalendar (firstweekday=0)

     This class can be used to generate plain text calendars.

     ‘TextCalendar’ instances have the following methods:

      -- Method: formatday (theday, weekday, width)

          Return a string representing a single day formatted with the
          given 'width'.  If 'theday' is ‘0’, return a string of spaces
          of the specified width, representing an empty day.  The
          'weekday' parameter is unused.

      -- Method: formatweek (theweek, w=0)

          Return a single week in a string with no newline.  If 'w' is
          provided, it specifies the width of the date columns, which
          are centered.  Depends on the first weekday as specified in
          the constructor or set by the *note setfirstweekday(): 2661.
          method.

      -- Method: formatweekday (weekday, width)

          Return a string representing the name of a single weekday
          formatted to the specified 'width'.  The 'weekday' parameter
          is an integer representing the day of the week, where ‘0’ is
          Monday and ‘6’ is Sunday.

      -- Method: formatweekheader (width)

          Return a string containing the header row of weekday names,
          formatted with the given 'width' for each column.  The names
          depend on the locale settings and are padded to the specified
          width.

      -- Method: formatmonth (theyear, themonth, w=0, l=0)

          Return a month’s calendar in a multi-line string.  If 'w' is
          provided, it specifies the width of the date columns, which
          are centered.  If 'l' is given, it specifies the number of
          lines that each week will use.  Depends on the first weekday
          as specified in the constructor or set by the *note
          setfirstweekday(): 2661. method.

      -- Method: formatmonthname (theyear, themonth, width=0,
               withyear=True)

          Return a string representing the month’s name centered within
          the specified 'width'.  If 'withyear' is ‘True’, include the
          year in the output.  The 'theyear' and 'themonth' parameters
          specify the year and month for the name to be formatted
          respectively.

      -- Method: prmonth (theyear, themonth, w=0, l=0)

          Print a month’s calendar as returned by *note formatmonth():
          2676.

      -- Method: formatyear (theyear, w=2, l=1, c=6, m=3)

          Return a 'm'-column calendar for an entire year as a
          multi-line string.  Optional parameters 'w', 'l', and 'c' are
          for date column width, lines per week, and number of spaces
          between month columns, respectively.  Depends on the first
          weekday as specified in the constructor or set by the *note
          setfirstweekday(): 2661. method.  The earliest year for which
          a calendar can be generated is platform-dependent.

      -- Method: pryear (theyear, w=2, l=1, c=6, m=3)

          Print the calendar for an entire year as returned by *note
          formatyear(): 2679.

 -- Class: calendar.HTMLCalendar (firstweekday=0)

     This class can be used to generate HTML calendars.

     ‘HTMLCalendar’ instances have the following methods:

      -- Method: formatmonth (theyear, themonth, withyear=True)

          Return a month’s calendar as an HTML table.  If 'withyear' is
          true the year will be included in the header, otherwise just
          the month name will be used.

      -- Method: formatyear (theyear, width=3)

          Return a year’s calendar as an HTML table.  'width'
          (defaulting to 3) specifies the number of months per row.

      -- Method: formatyearpage (theyear, width=3, css='calendar.css',
               encoding=None)

          Return a year’s calendar as a complete HTML page.  'width'
          (defaulting to 3) specifies the number of months per row.
          'css' is the name for the cascading style sheet to be used.
          *note None: 678. can be passed if no style sheet should be
          used.  'encoding' specifies the encoding to be used for the
          output (defaulting to the system default encoding).

      -- Method: formatmonthname (theyear, themonth, withyear=True)

          Return a month name as an HTML table row.  If 'withyear' is
          true the year will be included in the row, otherwise just the
          month name will be used.

     ‘HTMLCalendar’ has the following attributes you can override to
     customize the CSS classes used by the calendar:

      -- Attribute: cssclasses

          A list of CSS classes used for each weekday.  The default
          class list is:

               cssclasses = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"]

          more styles can be added for each day:

               cssclasses = ["mon text-bold", "tue", "wed", "thu", "fri", "sat", "sun red"]

          Note that the length of this list must be seven items.

      -- Attribute: cssclass_noday

          The CSS class for a weekday occurring in the previous or
          coming month.

          Added in version 3.7.

      -- Attribute: cssclasses_weekday_head

          A list of CSS classes used for weekday names in the header
          row.  The default is the same as *note cssclasses: 267f.

          Added in version 3.7.

      -- Attribute: cssclass_month_head

          The month’s head CSS class (used by *note formatmonthname():
          267e.).  The default value is ‘"month"’.

          Added in version 3.7.

      -- Attribute: cssclass_month

          The CSS class for the whole month’s table (used by *note
          formatmonth(): 267b.).  The default value is ‘"month"’.

          Added in version 3.7.

      -- Attribute: cssclass_year

          The CSS class for the whole year’s table of tables (used by
          *note formatyear(): 267c.).  The default value is ‘"year"’.

          Added in version 3.7.

      -- Attribute: cssclass_year_head

          The CSS class for the table head for the whole year (used by
          *note formatyear(): 267c.).  The default value is ‘"year"’.

          Added in version 3.7.

     Note that although the naming for the above described class
     attributes is singular (e.g.  ‘cssclass_month’ ‘cssclass_noday’),
     one can replace the single CSS class with a space separated list of
     CSS classes, for example:

          "text-bold text-red"

     Here is an example how ‘HTMLCalendar’ can be customized:

          class CustomHTMLCal(calendar.HTMLCalendar):
              cssclasses = [style + " text-nowrap" for style in
                            calendar.HTMLCalendar.cssclasses]
              cssclass_month_head = "text-center month-head"
              cssclass_month = "text-center month"
              cssclass_year = "text-italic lead"

 -- Class: calendar.LocaleTextCalendar (firstweekday=0, locale=None)

     This subclass of *note TextCalendar: 2671. can be passed a locale
     name in the constructor and will return month and weekday names in
     the specified locale.

 -- Class: calendar.LocaleHTMLCalendar (firstweekday=0, locale=None)

     This subclass of *note HTMLCalendar: b3b. can be passed a locale
     name in the constructor and will return month and weekday names in
     the specified locale.

     Note: The constructor, ‘formatweekday()’ and ‘formatmonthname()’
     methods of these two classes temporarily change the ‘LC_TIME’
     locale to the given 'locale'.  Because the current locale is a
     process-wide setting, they are not thread-safe.

For simple text calendars this module provides the following functions.

 -- Function: calendar.setfirstweekday (weekday)

     Sets the weekday (‘0’ is Monday, ‘6’ is Sunday) to start each week.
     The values *note MONDAY: 2663, *note TUESDAY: 2686, *note
     WEDNESDAY: 2687, *note THURSDAY: 2688, *note FRIDAY: 2689, *note
     SATURDAY: 268a, and *note SUNDAY: 2664. are provided for
     convenience.  For example, to set the first weekday to Sunday:

          import calendar
          calendar.setfirstweekday(calendar.SUNDAY)

 -- Function: calendar.firstweekday ()

     Returns the current setting for the weekday to start each week.

 -- Function: calendar.isleap (year)

     Returns *note True: c2d. if 'year' is a leap year, otherwise *note
     False: b4f.

 -- Function: calendar.leapdays (y1, y2)

     Returns the number of leap years in the range from 'y1' to 'y2'
     (exclusive), where 'y1' and 'y2' are years.

     This function works for ranges spanning a century change.

 -- Function: calendar.weekday (year, month, day)

     Returns the day of the week (‘0’ is Monday) for 'year' (‘1970’–…),
     'month' (‘1’–‘12’), 'day' (‘1’–‘31’).

 -- Function: calendar.weekheader (n)

     Return a header containing abbreviated weekday names.  'n'
     specifies the width in characters for one weekday.

 -- Function: calendar.monthrange (year, month)

     Returns weekday of first day of the month and number of days in
     month, for the specified 'year' and 'month'.

 -- Function: calendar.monthcalendar (year, month)

     Returns a matrix representing a month’s calendar.  Each row
     represents a week; days outside of the month are represented by
     zeros.  Each week begins with Monday unless set by *note
     setfirstweekday(): 2661.

 -- Function: calendar.prmonth (theyear, themonth, w=0, l=0)

     Prints a month’s calendar as returned by *note month(): 16a4.

 -- Function: calendar.month (theyear, themonth, w=0, l=0)

     Returns a month’s calendar in a multi-line string using the *note
     formatmonth(): 2676. of the *note TextCalendar: 2671. class.

 -- Function: calendar.prcal (year, w=0, l=0, c=6, m=3)

     Prints the calendar for an entire year as returned by *note
     calendar(): 14.

 -- Function: calendar.calendar (year, w=2, l=1, c=6, m=3)

     Returns a 3-column calendar for an entire year as a multi-line
     string using the *note formatyear(): 2679. of the *note
     TextCalendar: 2671. class.

 -- Function: calendar.timegm (tuple)

     An unrelated but handy function that takes a time tuple such as
     returned by the *note gmtime(): 1205. function in the *note time:
     ee. module, and returns the corresponding Unix timestamp value,
     assuming an epoch of 1970, and the POSIX encoding.  In fact,
     ‘time.gmtime()’ and ‘timegm()’ are each others’ inverse.

The ‘calendar’ module exports the following data attributes:

 -- Data: calendar.day_name

     A sequence that represents the days of the week in the current
     locale, where Monday is day number 0.

          >>> import calendar
          >>> list(calendar.day_name)
          ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']

 -- Data: calendar.day_abbr

     A sequence that represents the abbreviated days of the week in the
     current locale, where Mon is day number 0.

          >>> import calendar
          >>> list(calendar.day_abbr)
          ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']

 -- Data: calendar.MONDAY
 -- Data: calendar.TUESDAY
 -- Data: calendar.WEDNESDAY
 -- Data: calendar.THURSDAY
 -- Data: calendar.FRIDAY
 -- Data: calendar.SATURDAY
 -- Data: calendar.SUNDAY

     Aliases for the days of the week, where ‘MONDAY’ is ‘0’ and
     ‘SUNDAY’ is ‘6’.

     Added in version 3.12.

 -- Class: calendar.Day

     Enumeration defining days of the week as integer constants.  The
     members of this enumeration are exported to the module scope as
     *note MONDAY: 2663. through *note SUNDAY: 2664.

     Added in version 3.12.

 -- Data: calendar.month_name

     A sequence that represents the months of the year in the current
     locale.  This follows normal convention of January being month
     number 1, so it has a length of 13 and ‘month_name[0]’ is the empty
     string.

          >>> import calendar
          >>> list(calendar.month_name)
          ['', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']

 -- Data: calendar.month_abbr

     A sequence that represents the abbreviated months of the year in
     the current locale.  This follows normal convention of January
     being month number 1, so it has a length of 13 and ‘month_abbr[0]’
     is the empty string.

          >>> import calendar
          >>> list(calendar.month_abbr)
          ['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']

 -- Data: calendar.JANUARY
 -- Data: calendar.FEBRUARY
 -- Data: calendar.MARCH
 -- Data: calendar.APRIL
 -- Data: calendar.MAY
 -- Data: calendar.JUNE
 -- Data: calendar.JULY
 -- Data: calendar.AUGUST
 -- Data: calendar.SEPTEMBER
 -- Data: calendar.OCTOBER
 -- Data: calendar.NOVEMBER
 -- Data: calendar.DECEMBER

     Aliases for the months of the year, where ‘JANUARY’ is ‘1’ and
     ‘DECEMBER’ is ‘12’.

     Added in version 3.12.

 -- Class: calendar.Month

     Enumeration defining months of the year as integer constants.  The
     members of this enumeration are exported to the module scope as
     *note JANUARY: 2f9. through *note DECEMBER: 26a3.

     Added in version 3.12.

The ‘calendar’ module defines the following exceptions:

 -- Exception: calendar.IllegalMonthError (month)

     A subclass of *note ValueError: 202, raised when the given month
     number is outside of the range 1-12 (inclusive).

      -- Attribute: month

          The invalid month number.

 -- Exception: calendar.IllegalWeekdayError (weekday)

     A subclass of *note ValueError: 202, raised when the given weekday
     number is outside of the range 0-6 (inclusive).

      -- Attribute: weekday

          The invalid weekday number.

See also
........

Module *note datetime: 30.

     Object-oriented interface to dates and times with similar
     functionality to the *note time: ee. module.

Module *note time: ee.

     Low-level time related functions.

* Menu:

* Command-Line Usage::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/calendar.py


File: python.info,  Node: Command-Line Usage,  Up: calendar — General calendar-related functions

5.8.3.1 Command-Line Usage
..........................

Added in version 2.5.

The ‘calendar’ module can be executed as a script from the command line
to interactively print a calendar.

     python -m calendar [-h] [-L LOCALE] [-e ENCODING] [-t {text,html}]
                        [-w WIDTH] [-l LINES] [-s SPACING] [-m MONTHS] [-c CSS]
                        [-f FIRST_WEEKDAY] [year] [month]

For example, to print a calendar for the year 2000:

     $ python -m calendar 2000
                                       2000

           January                   February                   March
     Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                     1  2          1  2  3  4  5  6             1  2  3  4  5
      3  4  5  6  7  8  9       7  8  9 10 11 12 13       6  7  8  9 10 11 12
     10 11 12 13 14 15 16      14 15 16 17 18 19 20      13 14 15 16 17 18 19
     17 18 19 20 21 22 23      21 22 23 24 25 26 27      20 21 22 23 24 25 26
     24 25 26 27 28 29 30      28 29                     27 28 29 30 31
     31

            April                      May                       June
     Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                     1  2       1  2  3  4  5  6  7                1  2  3  4
      3  4  5  6  7  8  9       8  9 10 11 12 13 14       5  6  7  8  9 10 11
     10 11 12 13 14 15 16      15 16 17 18 19 20 21      12 13 14 15 16 17 18
     17 18 19 20 21 22 23      22 23 24 25 26 27 28      19 20 21 22 23 24 25
     24 25 26 27 28 29 30      29 30 31                  26 27 28 29 30

             July                     August                  September
     Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                     1  2          1  2  3  4  5  6                   1  2  3
      3  4  5  6  7  8  9       7  8  9 10 11 12 13       4  5  6  7  8  9 10
     10 11 12 13 14 15 16      14 15 16 17 18 19 20      11 12 13 14 15 16 17
     17 18 19 20 21 22 23      21 22 23 24 25 26 27      18 19 20 21 22 23 24
     24 25 26 27 28 29 30      28 29 30 31               25 26 27 28 29 30
     31

           October                   November                  December
     Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
                        1             1  2  3  4  5                   1  2  3
      2  3  4  5  6  7  8       6  7  8  9 10 11 12       4  5  6  7  8  9 10
      9 10 11 12 13 14 15      13 14 15 16 17 18 19      11 12 13 14 15 16 17
     16 17 18 19 20 21 22      20 21 22 23 24 25 26      18 19 20 21 22 23 24
     23 24 25 26 27 28 29      27 28 29 30               25 26 27 28 29 30 31
     30 31

The following options are accepted:

 -- Option: --help, -h

     Show the help message and exit.

 -- Option: --locale LOCALE, -L LOCALE

     The locale to use for month and weekday names.  Defaults to
     English.

 -- Option: --encoding ENCODING, -e ENCODING

     The encoding to use for output.  *note -encoding: 26ad. is required
     if *note -locale: 26ab. is set.

 -- Option: --type {text,html}, -t {text,html}

     Print the calendar to the terminal as text, or as an HTML document.

 -- Option: --first-weekday FIRST_WEEKDAY, -f FIRST_WEEKDAY

     The weekday to start each week.  Must be a number between 0
     (Monday) and 6 (Sunday).  Defaults to 0.

     Added in version 3.13.

 -- Option: year

     The year to print the calendar for.  Defaults to the current year.

 -- Option: month

     The month of the specified *note year: 26b3. to print the calendar
     for.  Must be a number between 1 and 12, and may only be used in
     text mode.  Defaults to printing a calendar for the full year.

'Text-mode options:'

 -- Option: --width WIDTH, -w WIDTH

     The width of the date column in terminal columns.  The date is
     printed centred in the column.  Any value lower than 2 is ignored.
     Defaults to 2.

 -- Option: --lines LINES, -l LINES

     The number of lines for each week in terminal rows.  The date is
     printed top-aligned.  Any value lower than 1 is ignored.  Defaults
     to 1.

 -- Option: --spacing SPACING, -s SPACING

     The space between months in columns.  Any value lower than 2 is
     ignored.  Defaults to 6.

 -- Option: --months MONTHS, -m MONTHS

     The number of months printed per row.  Defaults to 3.

'HTML-mode options:'

 -- Option: --css CSS, -c CSS

     The path of a CSS stylesheet to use for the calendar.  This must
     either be relative to the generated HTML, or an absolute HTTP or
     ‘file:///’ URL.


File: python.info,  Node: collections — Container datatypes,  Next: collections abc — Abstract Base Classes for Containers,  Prev: calendar — General calendar-related functions,  Up: Data Types

5.8.4 ‘collections’ — Container datatypes
-----------------------------------------

'Source code:' Lib/collections/__init__.py(1)

__________________________________________________________________

This module implements specialized container datatypes providing
alternatives to Python’s general purpose built-in containers, *note
dict: 256, *note list: 614, *note set: 5dc, and *note tuple: 373.

*note namedtuple(): 1ca.  factory function for creating tuple subclasses with named fields
                          
                          
*note deque: 5df.         list-like container with fast appends and pops on either end
                          
                          
*note ChainMap: c3c.      dict-like class for creating a single view of multiple mappings
                          
                          
*note Counter: 10d5.      dict subclass for counting *note hashable: 613. objects
                          
                          
*note OrderedDict: 5de.   dict subclass that remembers the order entries were added
                          
                          
*note defaultdict: 1201.  dict subclass that calls a factory function to supply missing values
                          
                          
*note UserDict: 1b26.     wrapper around dictionary objects for easier dict subclassing
                          
                          
*note UserList: 1533.     wrapper around list objects for easier list subclassing
                          
                          
*note UserString: e03.    wrapper around string objects for easier string subclassing
                          

* Menu:

* ChainMap objects::
* Counter objects::
* deque objects::
* defaultdict objects::
* namedtuple() Factory Function for Tuples with Named Fields: namedtuple Factory Function for Tuples with Named Fields.
* OrderedDict objects::
* UserDict objects::
* UserList objects::
* UserString objects::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/collections/__init__.py


File: python.info,  Node: ChainMap objects,  Next: Counter objects,  Up: collections — Container datatypes

5.8.4.1 ‘ChainMap’ objects
..........................

Added in version 3.3.

A *note ChainMap: c3c. class is provided for quickly linking a number of
mappings so they can be treated as a single unit.  It is often much
faster than creating a new dictionary and running multiple *note
update(): 14b4. calls.

The class can be used to simulate nested scopes and is useful in
templating.

 -- Class: collections.ChainMap (*maps)

     A ‘ChainMap’ groups multiple dicts or other mappings together to
     create a single, updateable view.  If no 'maps' are specified, a
     single empty dictionary is provided so that a new chain always has
     at least one mapping.

     The underlying mappings are stored in a list.  That list is public
     and can be accessed or updated using the 'maps' attribute.  There
     is no other state.

     Lookups search the underlying mappings successively until a key is
     found.  In contrast, writes, updates, and deletions only operate on
     the first mapping.

     A ‘ChainMap’ incorporates the underlying mappings by reference.
     So, if one of the underlying mappings gets updated, those changes
     will be reflected in ‘ChainMap’.

     All of the usual dictionary methods are supported.  In addition,
     there is a 'maps' attribute, a method for creating new subcontexts,
     and a property for accessing all but the first mapping:

      -- Attribute: maps

          A user updateable list of mappings.  The list is ordered from
          first-searched to last-searched.  It is the only stored state
          and can be modified to change which mappings are searched.
          The list should always contain at least one mapping.

      -- Method: new_child (m=None, **kwargs)

          Returns a new ‘ChainMap’ containing a new map followed by all
          of the maps in the current instance.  If ‘m’ is specified, it
          becomes the new map at the front of the list of mappings; if
          not specified, an empty dict is used, so that a call to
          ‘d.new_child()’ is equivalent to: ‘ChainMap({}, *d.maps)’.  If
          any keyword arguments are specified, they update passed map or
          new empty dict.  This method is used for creating subcontexts
          that can be updated without altering values in any of the
          parent mappings.

          Changed in version 3.4: The optional ‘m’ parameter was added.

          Changed in version 3.10: Keyword arguments support was added.

      -- Attribute: parents

          Property returning a new ‘ChainMap’ containing all of the maps
          in the current instance except the first one.  This is useful
          for skipping the first map in the search.  Use cases are
          similar to those for the *note nonlocal: 12ef. keyword used in
          *note nested scopes: 20f3.  The use cases also parallel those
          for the built-in *note super(): 4de. function.  A reference to
          ‘d.parents’ is equivalent to: ‘ChainMap(*d.maps[1:])’.

     Note, the iteration order of a ‘ChainMap’ is determined by scanning
     the mappings last to first:

          >>> baseline = {'music': 'bach', 'art': 'rembrandt'}
          >>> adjustments = {'art': 'van gogh', 'opera': 'carmen'}
          >>> list(ChainMap(adjustments, baseline))
          ['music', 'art', 'opera']

     This gives the same ordering as a series of *note dict.update():
     14b4. calls starting with the last mapping:

          >>> combined = baseline.copy()
          >>> combined.update(adjustments)
          >>> list(combined)
          ['music', 'art', 'opera']

     Changed in version 3.9: Added support for ‘|’ and ‘|=’ operators,
     specified in PEP 584(1).

See also
........

   * The MultiContext class(2) in the Enthought CodeTools package(3) has
     options to support writing to any mapping in the chain.

   * Django’s Context class(4) for templating is a read-only chain of
     mappings.  It also features pushing and popping of contexts similar
     to the *note new_child(): f5a. method and the *note parents: 26c4.
     property.

   * The Nested Contexts recipe(5) has options to control whether writes
     and other mutations apply only to the first mapping or to any
     mapping in the chain.

   * A greatly simplified read-only version of Chainmap(6).

* Menu:

* ChainMap Examples and Recipes::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0584/

   (2) 
https://github.com/enthought/codetools/blob/4.0.0/codetools/contexts/multi_context.py

   (3) https://github.com/enthought/codetools

   (4) 
https://github.com/django/django/blob/main/django/template/context.py

   (5) 
https://code.activestate.com/recipes/577434-nested-contexts-a-chain-of-mapping-objects/

   (6) https://code.activestate.com/recipes/305268/


File: python.info,  Node: ChainMap Examples and Recipes,  Up: ChainMap objects

5.8.4.2 ‘ChainMap’ Examples and Recipes
.......................................

This section shows various approaches to working with chained maps.

Example of simulating Python’s internal lookup chain:

     import builtins
     pylookup = ChainMap(locals(), globals(), vars(builtins))

Example of letting user specified command-line arguments take precedence
over environment variables which in turn take precedence over default
values:

     import os, argparse

     defaults = {'color': 'red', 'user': 'guest'}

     parser = argparse.ArgumentParser()
     parser.add_argument('-u', '--user')
     parser.add_argument('-c', '--color')
     namespace = parser.parse_args()
     command_line_args = {k: v for k, v in vars(namespace).items() if v is not None}

     combined = ChainMap(command_line_args, os.environ, defaults)
     print(combined['color'])
     print(combined['user'])

Example patterns for using the *note ChainMap: c3c. class to simulate
nested contexts:

     c = ChainMap()        # Create root context
     d = c.new_child()     # Create nested child context
     e = c.new_child()     # Child of c, independent from d
     e.maps[0]             # Current context dictionary -- like Python's locals()
     e.maps[-1]            # Root context -- like Python's globals()
     e.parents             # Enclosing context chain -- like Python's nonlocals

     d['x'] = 1            # Set value in current context
     d['x']                # Get first key in the chain of contexts
     del d['x']            # Delete from current context
     list(d)               # All nested values
     k in d                # Check all nested values
     len(d)                # Number of nested values
     d.items()             # All nested items
     dict(d)               # Flatten into a regular dictionary

The *note ChainMap: c3c. class only makes updates (writes and deletions)
to the first mapping in the chain while lookups will search the full
chain.  However, if deep writes and deletions are desired, it is easy to
make a subclass that updates keys found deeper in the chain:

     class DeepChainMap(ChainMap):
         'Variant of ChainMap that allows direct updates to inner scopes'

         def __setitem__(self, key, value):
             for mapping in self.maps:
                 if key in mapping:
                     mapping[key] = value
                     return
             self.maps[0][key] = value

         def __delitem__(self, key):
             for mapping in self.maps:
                 if key in mapping:
                     del mapping[key]
                     return
             raise KeyError(key)

     >>> d = DeepChainMap({'zebra': 'black'}, {'elephant': 'blue'}, {'lion': 'yellow'})
     >>> d['lion'] = 'orange'         # update an existing key two levels down
     >>> d['snake'] = 'red'           # new keys get added to the topmost dict
     >>> del d['elephant']            # remove an existing key one level down
     >>> d                            # display result
     DeepChainMap({'zebra': 'black', 'snake': 'red'}, {}, {'lion': 'orange'})


File: python.info,  Node: Counter objects,  Next: deque objects,  Prev: ChainMap objects,  Up: collections — Container datatypes

5.8.4.3 ‘Counter’ objects
.........................

A counter tool is provided to support convenient and rapid tallies.  For
example:

     >>> # Tally occurrences of words in a list
     >>> cnt = Counter()
     >>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:
     ...     cnt[word] += 1
     ...
     >>> cnt
     Counter({'blue': 3, 'red': 2, 'green': 1})

     >>> # Find the ten most common words in Hamlet
     >>> import re
     >>> words = re.findall(r'\w+', open('hamlet.txt').read().lower())
     >>> Counter(words).most_common(10)
     [('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),
      ('you', 554),  ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)]

 -- Class: collections.Counter (**kwargs)

 -- Class: collections.Counter (iterable, /, **kwargs)

 -- Class: collections.Counter (mapping, /, **kwargs)

     A ‘Counter’ is a *note dict: 256. subclass for counting *note
     hashable: 613. objects.  It is a collection where elements are
     stored as dictionary keys and their counts are stored as dictionary
     values.  Counts are allowed to be any integer value including zero
     or negative counts.  The ‘Counter’ class is similar to bags or
     multisets in other languages.

     Elements are counted from an 'iterable' or initialized from another
     'mapping' (or counter):

          >>> c = Counter()                           # a new, empty counter
          >>> c = Counter('gallahad')                 # a new counter from an iterable
          >>> c = Counter({'red': 4, 'blue': 2})      # a new counter from a mapping
          >>> c = Counter(cats=4, dogs=8)             # a new counter from keyword args

     Counter objects have a dictionary interface except that they return
     a zero count for missing items instead of raising a *note KeyError:
     345.:

          >>> c = Counter(['eggs', 'ham'])
          >>> c['bacon']                              # count of a missing element is zero
          0

     Setting a count to zero does not remove an element from a counter.
     Use ‘del’ to remove it entirely:

          >>> c['sausage'] = 0                        # counter entry with a zero count
          >>> del c['sausage']                        # del actually removes the entry

     Added in version 3.1.

     Changed in version 3.7: As a *note dict: 256. subclass, ‘Counter’
     inherited the capability to remember insertion order.  Math
     operations on 'Counter' objects also preserve order.  Results are
     ordered according to when an element is first encountered in the
     left operand and then by the order encountered in the right
     operand.

     Counter objects support additional methods beyond those available
     for all dictionaries:

      -- Method: elements ()

          Return an iterator over elements repeating each as many times
          as its count.  Elements are returned in the order first
          encountered.  If an element’s count is less than one,
          ‘elements()’ will ignore it.

               >>> c = Counter(a=4, b=2, c=0, d=-2)
               >>> sorted(c.elements())
               ['a', 'a', 'a', 'a', 'b', 'b']

      -- Method: most_common (n=None)

          Return a list of the 'n' most common elements and their counts
          from the most common to the least.  If 'n' is omitted or
          ‘None’, ‘most_common()’ returns 'all' elements in the counter.
          Elements with equal counts are ordered in the order first
          encountered:

               >>> Counter('abracadabra').most_common(3)
               [('a', 5), ('b', 2), ('r', 2)]

      -- Method: subtract (**kwargs)

      -- Method: subtract (iterable, /, **kwargs)

      -- Method: subtract (mapping, /, **kwargs)

          Elements are subtracted from an 'iterable' or from another
          'mapping' (or counter).  Like *note dict.update(): 14b4. but
          subtracts counts instead of replacing them.  Both inputs and
          outputs may be zero or negative.

               >>> c = Counter(a=4, b=2, c=0, d=-2)
               >>> d = Counter(a=1, b=2, c=3, d=4)
               >>> c.subtract(d)
               >>> c
               Counter({'a': 3, 'b': 0, 'c': -3, 'd': -6})

          Added in version 3.2.

      -- Method: total ()

          Compute the sum of the counts.

               >>> c = Counter(a=10, b=5, c=0)
               >>> c.total()
               15

          Added in version 3.10.

     The usual dictionary methods are available for ‘Counter’ objects
     except for two which work differently for counters.

      -- Method: fromkeys (iterable)

          This class method is not implemented for ‘Counter’ objects.

      -- Method: update (**kwargs)

      -- Method: update (iterable, /, **kwargs)

      -- Method: update (mapping, /, **kwargs)

          Elements are counted from an 'iterable' or added-in from
          another 'mapping' (or counter).  Like *note dict.update():
          14b4. but adds counts instead of replacing them.  Also, the
          'iterable' is expected to be a sequence of elements, not a
          sequence of ‘(key, value)’ pairs.

Counters support rich comparison operators for equality, subset, and
superset relationships: ‘==’, ‘!=’, ‘<’, ‘<=’, ‘>’, ‘>=’.  All of those
tests treat missing elements as having zero counts so that ‘Counter(a=1)
== Counter(a=1, b=0)’ returns true.

Changed in version 3.10: Rich comparison operations were added.

Changed in version 3.10: In equality tests, missing elements are treated
as having zero counts.  Formerly, ‘Counter(a=3)’ and ‘Counter(a=3, b=0)’
were considered distinct.

Common patterns for working with *note Counter: 10d5. objects:

     c.total()                       # total of all counts
     c.clear()                       # reset all counts
     list(c)                         # list unique elements
     set(c)                          # convert to a set
     dict(c)                         # convert to a regular dictionary
     c.items()                       # access the (elem, cnt) pairs
     Counter(dict(list_of_pairs))    # convert from a list of (elem, cnt) pairs
     c.most_common()[:-n-1:-1]       # n least common elements
     +c                              # remove zero and negative counts

Several mathematical operations are provided for combining *note
Counter: 10d5. objects to produce multisets (counters that have counts
greater than zero).  Addition and subtraction combine counters by adding
or subtracting the counts of corresponding elements.  Intersection and
union return the minimum and maximum of corresponding counts.  Equality
and inclusion compare corresponding counts.  Each operation can accept
inputs with signed counts, but the output will exclude results with
counts of zero or less.

     >>> c = Counter(a=3, b=1)
     >>> d = Counter(a=1, b=2)
     >>> c + d                       # add two counters together:  c[x] + d[x]
     Counter({'a': 4, 'b': 3})
     >>> c - d                       # subtract (keeping only positive counts)
     Counter({'a': 2})
     >>> c & d                       # intersection:  min(c[x], d[x])
     Counter({'a': 1, 'b': 1})
     >>> c | d                       # union:  max(c[x], d[x])
     Counter({'a': 3, 'b': 2})
     >>> c == d                      # equality:  c[x] == d[x]
     False
     >>> c <= d                      # inclusion:  c[x] <= d[x]
     False

Unary addition and subtraction are shortcuts for adding an empty counter
or subtracting from an empty counter.

     >>> c = Counter(a=2, b=-4)
     >>> +c
     Counter({'a': 2})
     >>> -c
     Counter({'b': 4})

Added in version 3.3: Added support for unary plus, unary minus, and
in-place multiset operations.

     Note: Counters were primarily designed to work with positive
     integers to represent running counts; however, care was taken to
     not unnecessarily preclude use cases needing other types or
     negative values.  To help with those use cases, this section
     documents the minimum range and type restrictions.

        * The *note Counter: 10d5. class itself is a dictionary subclass
          with no restrictions on its keys and values.  The values are
          intended to be numbers representing counts, but you 'could'
          store anything in the value field.

        * The *note most_common(): 134c. method requires only that the
          values be orderable.

        * For in-place operations such as ‘c[key] += 1’, the value type
          need only support addition and subtraction.  So fractions,
          floats, and decimals would work and negative values are
          supported.  The same is also true for *note update(): 15c8.
          and *note subtract(): 1223. which allow negative and zero
          values for both inputs and outputs.

        * The multiset methods are designed only for use cases with
          positive values.  The inputs may be negative or zero, but only
          outputs with positive values are created.  There are no type
          restrictions, but the value type needs to support addition,
          subtraction, and comparison.

        * The *note elements(): 134d. method requires integer counts.
          It ignores zero and negative counts.

See also
........

   * Bag class(1) in Smalltalk.

   * Wikipedia entry for Multisets(2).

   * C++ multisets(3) tutorial with examples.

   * For mathematical operations on multisets and their use cases, see
     'Knuth, Donald.  The Art of Computer Programming Volume II, Section
     4.6.3, Exercise 19'.

   * To enumerate all distinct multisets of a given size over a given
     set of elements, see *note
     itertools.combinations_with_replacement(): 12c8.:

          map(Counter, combinations_with_replacement('ABC', 2)) # --> AA AB AC BB BC CC

   ---------- Footnotes ----------

   (1) 
https://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html

   (2) https://en.wikipedia.org/wiki/Multiset

   (3) 
http://www.java2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm


File: python.info,  Node: deque objects,  Next: defaultdict objects,  Prev: Counter objects,  Up: collections — Container datatypes

5.8.4.4 ‘deque’ objects
.......................

 -- Class: collections.deque ([iterable[, maxlen]])

     Returns a new deque object initialized left-to-right (using *note
     append(): 26ca.) with data from 'iterable'.  If 'iterable' is not
     specified, the new deque is empty.

     Deques are a generalization of stacks and queues (the name is
     pronounced “deck” and is short for “double-ended queue”).  Deques
     support thread-safe, memory efficient appends and pops from either
     side of the deque with approximately the same 'O'(1) performance in
     either direction.

     Though *note list: 614. objects support similar operations, they
     are optimized for fast fixed-length operations and incur 'O'('n')
     memory movement costs for ‘pop(0)’ and ‘insert(0, v)’ operations
     which change both the size and position of the underlying data
     representation.

     If 'maxlen' is not specified or is ‘None’, deques may grow to an
     arbitrary length.  Otherwise, the deque is bounded to the specified
     maximum length.  Once a bounded length deque is full, when new
     items are added, a corresponding number of items are discarded from
     the opposite end.  Bounded length deques provide functionality
     similar to the ‘tail’ filter in Unix.  They are also useful for
     tracking transactions and other pools of data where only the most
     recent activity is of interest.

     Deque objects support the following methods:

      -- Method: append (item, /)

          Add 'item' to the right side of the deque.

      -- Method: appendleft (item, /)

          Add 'item' to the left side of the deque.

      -- Method: clear ()

          Remove all elements from the deque leaving it with length 0.

      -- Method: copy ()

          Create a shallow copy of the deque.

          Added in version 3.5.

      -- Method: count (value, /)

          Count the number of deque elements equal to 'value'.

          Added in version 3.2.

      -- Method: extend (iterable, /)

          Extend the right side of the deque by appending elements from
          the iterable argument.

      -- Method: extendleft (iterable, /)

          Extend the left side of the deque by appending elements from
          'iterable'.  Note, the series of left appends results in
          reversing the order of elements in the iterable argument.

      -- Method: index (value[, start[, stop]])

          Return the position of 'value' in the deque (at or after index
          'start' and before index 'stop').  Returns the first match or
          raises *note ValueError: 202. if not found.

          Added in version 3.5.

      -- Method: insert (index, value, /)

          Insert 'value' into the deque at position 'index'.

          If the insertion would cause a bounded deque to grow beyond
          'maxlen', an *note IndexError: 1585. is raised.

          Added in version 3.5.

      -- Method: pop ()

          Remove and return an element from the right side of the deque.
          If no elements are present, raises an *note IndexError: 1585.

      -- Method: popleft ()

          Remove and return an element from the left side of the deque.
          If no elements are present, raises an *note IndexError: 1585.

      -- Method: remove (value, /)

          Remove the first occurrence of 'value'.  If not found, raises
          a *note ValueError: 202.

      -- Method: reverse ()

          Reverse the elements of the deque in-place and then return
          ‘None’.

          Added in version 3.2.

      -- Method: rotate (n=1, /)

          Rotate the deque 'n' steps to the right.  If 'n' is negative,
          rotate to the left.

          When the deque is not empty, rotating one step to the right is
          equivalent to ‘d.appendleft(d.pop())’, and rotating one step
          to the left is equivalent to ‘d.append(d.popleft())’.

     Deque objects also provide one read-only attribute:

      -- Attribute: maxlen

          Maximum size of a deque or ‘None’ if unbounded.

          Added in version 3.1.

In addition to the above, deques support iteration, pickling, ‘len(d)’,
‘reversed(d)’, ‘copy.copy(d)’, ‘copy.deepcopy(d)’, membership testing
with the *note in: 2f4. operator, and subscript references such as
‘d[0]’ to access the first element.  Indexed access is 'O'(1) at both
ends but slows to 'O'('n') in the middle.  For fast random access, use
lists instead.

Starting in version 3.5, deques support ‘__add__()’, ‘__mul__()’, and
‘__imul__()’.

Example:

     >>> from collections import deque
     >>> d = deque('ghi')                 # make a new deque with three items
     >>> for elem in d:                   # iterate over the deque's elements
     ...     print(elem.upper())
     G
     H
     I

     >>> d.append('j')                    # add a new entry to the right side
     >>> d.appendleft('f')                # add a new entry to the left side
     >>> d                                # show the representation of the deque
     deque(['f', 'g', 'h', 'i', 'j'])

     >>> d.pop()                          # return and remove the rightmost item
     'j'
     >>> d.popleft()                      # return and remove the leftmost item
     'f'
     >>> list(d)                          # list the contents of the deque
     ['g', 'h', 'i']
     >>> d[0]                             # peek at leftmost item
     'g'
     >>> d[-1]                            # peek at rightmost item
     'i'

     >>> list(reversed(d))                # list the contents of a deque in reverse
     ['i', 'h', 'g']
     >>> 'h' in d                         # search the deque
     True
     >>> d.extend('jkl')                  # add multiple elements at once
     >>> d
     deque(['g', 'h', 'i', 'j', 'k', 'l'])
     >>> d.rotate(1)                      # right rotation
     >>> d
     deque(['l', 'g', 'h', 'i', 'j', 'k'])
     >>> d.rotate(-1)                     # left rotation
     >>> d
     deque(['g', 'h', 'i', 'j', 'k', 'l'])

     >>> deque(reversed(d))               # make a new deque in reverse order
     deque(['l', 'k', 'j', 'i', 'h', 'g'])
     >>> d.clear()                        # empty the deque
     >>> d.pop()                          # cannot pop from an empty deque
     Traceback (most recent call last):
         File "<pyshell#6>", line 1, in -toplevel-
             d.pop()
     IndexError: pop from an empty deque

     >>> d.extendleft('abc')              # extendleft() reverses the input order
     >>> d
     deque(['c', 'b', 'a'])

* Menu:

* deque Recipes::


File: python.info,  Node: deque Recipes,  Up: deque objects

5.8.4.5 ‘deque’ Recipes
.......................

This section shows various approaches to working with deques.

Bounded length deques provide functionality similar to the ‘tail’ filter
in Unix:

     def tail(filename, n=10):
         'Return the last n lines of a file'
         with open(filename) as f:
             return deque(f, n)

Another approach to using deques is to maintain a sequence of recently
added elements by appending to the right and popping to the left:

     def moving_average(iterable, n=3):
         # moving_average([40, 30, 50, 46, 39, 44]) --> 40.0 42.0 45.0 43.0
         # https://en.wikipedia.org/wiki/Moving_average
         it = iter(iterable)
         d = deque(itertools.islice(it, n-1))
         d.appendleft(0)
         s = sum(d)
         for elem in it:
             s += elem - d.popleft()
             d.append(elem)
             yield s / n

A round-robin scheduler(1) can be implemented with input iterators
stored in a *note deque: 5df.  Values are yielded from the active
iterator in position zero.  If that iterator is exhausted, it can be
removed with *note popleft(): 26d0.; otherwise, it can be cycled back to
the end with the *note rotate(): 1a36. method:

     def roundrobin(*iterables):
         "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
         iterators = deque(map(iter, iterables))
         while iterators:
             try:
                 while True:
                     yield next(iterators[0])
                     iterators.rotate(-1)
             except StopIteration:
                 # Remove an exhausted iterator.
                 iterators.popleft()

The *note rotate(): 1a36. method provides a way to implement *note
deque: 5df. slicing and deletion.  For example, a pure Python
implementation of ‘del d[n]’ relies on the ‘rotate()’ method to position
elements to be popped:

     def delete_nth(d, n):
         d.rotate(-n)
         d.popleft()
         d.rotate(n)

To implement *note deque: 5df. slicing, use a similar approach applying
*note rotate(): 1a36. to bring a target element to the left side of the
deque.  Remove old entries with *note popleft(): 26d0, add new entries
with *note extend(): 26cd, and then reverse the rotation.  With minor
variations on that approach, it is easy to implement Forth style stack
manipulations such as ‘dup’, ‘drop’, ‘swap’, ‘over’, ‘pick’, ‘rot’, and
‘roll’.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Round-robin_scheduling


File: python.info,  Node: defaultdict objects,  Next: namedtuple Factory Function for Tuples with Named Fields,  Prev: deque objects,  Up: collections — Container datatypes

5.8.4.6 ‘defaultdict’ objects
.............................

 -- Class: collections.defaultdict (default_factory=None, /, **kwargs)

 -- Class: collections.defaultdict (default_factory, mapping, /,
          **kwargs)

 -- Class: collections.defaultdict (default_factory, iterable, /,
          **kwargs)

     Return a new dictionary-like object.  ‘defaultdict’ is a subclass
     of the built-in *note dict: 256. class.  It overrides one method
     and adds one writable instance variable.  The remaining
     functionality is the same as for the ‘dict’ class and is not
     documented here.

     The first argument provides the initial value for the *note
     default_factory: 26d3. attribute; it defaults to ‘None’.  All
     remaining arguments are treated the same as if they were passed to
     the *note dict: 256. constructor, including keyword arguments.

     ‘defaultdict’ objects support the following method in addition to
     the standard *note dict: 256. operations:

      -- Method: __missing__ (key, /)

          If the *note default_factory: 26d3. attribute is ‘None’, this
          raises a *note KeyError: 345. exception with the 'key' as
          argument.

          If *note default_factory: 26d3. is not ‘None’, it is called
          without arguments to provide a default value for the given
          'key', this value is inserted in the dictionary for the 'key',
          and returned.

          If calling *note default_factory: 26d3. raises an exception
          this exception is propagated unchanged.

          This method is called by the *note __getitem__(): 283. method
          of the *note dict: 256. class when the requested key is not
          found; whatever it returns or raises is then returned or
          raised by ‘__getitem__()’.

          Note that ‘__missing__()’ is 'not' called for any operations
          besides *note __getitem__(): 283.  This means that *note
          get(): 1dea. will, like normal dictionaries, return ‘None’ as
          a default rather than using *note default_factory: 26d3.

     ‘defaultdict’ objects support the following instance variable:

      -- Attribute: default_factory

          This attribute is used by the *note __missing__(): 26d4.
          method; it is initialized from the first argument to the
          constructor, if present, or to ‘None’, if absent.

     Changed in version 3.9: Added merge (‘|’) and update (‘|=’)
     operators, specified in PEP 584(1).

* Menu:

* defaultdict Examples::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0584/


File: python.info,  Node: defaultdict Examples,  Up: defaultdict objects

5.8.4.7 ‘defaultdict’ Examples
..............................

Using *note list: 614. as the *note default_factory: 26d3, it is easy to
group a sequence of key-value pairs into a dictionary of lists:

     >>> s = [('yellow', 1), ('blue', 2), ('yellow', 3), ('blue', 4), ('red', 1)]
     >>> d = defaultdict(list)
     >>> for k, v in s:
     ...     d[k].append(v)
     ...
     >>> sorted(d.items())
     [('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

When each key is encountered for the first time, it is not already in
the mapping; so an entry is automatically created using the *note
default_factory: 26d3. function which returns an empty *note list: 614.
The *note list.append(): 6d0. operation then attaches the value to the
new list.  When keys are encountered again, the look-up proceeds
normally (returning the list for that key) and the ‘list.append()’
operation adds another value to the list.  This technique is simpler and
faster than an equivalent technique using *note dict.setdefault():
10b7.:

     >>> d = {}
     >>> for k, v in s:
     ...     d.setdefault(k, []).append(v)
     ...
     >>> sorted(d.items())
     [('blue', [2, 4]), ('red', [1]), ('yellow', [1, 3])]

Setting the *note default_factory: 26d3. to *note int: 257. makes the
*note defaultdict: 1201. useful for counting (like a bag or multiset in
other languages):

     >>> s = 'mississippi'
     >>> d = defaultdict(int)
     >>> for k in s:
     ...     d[k] += 1
     ...
     >>> sorted(d.items())
     [('i', 4), ('m', 1), ('p', 2), ('s', 4)]

When a letter is first encountered, it is missing from the mapping, so
the *note default_factory: 26d3. function calls *note int(): 257. to
supply a default count of zero.  The increment operation then builds up
the count for each letter.

The function *note int(): 257. which always returns zero is just a
special case of constant functions.  A faster and more flexible way to
create constant functions is to use a lambda function which can supply
any constant value (not just zero):

     >>> def constant_factory(value):
     ...     return lambda: value
     ...
     >>> d = defaultdict(constant_factory('<missing>'))
     >>> d.update(name='John', action='ran')
     >>> '%(name)s %(action)s to %(object)s' % d
     'John ran to <missing>'

Setting the *note default_factory: 26d3. to *note set: 5dc. makes the
*note defaultdict: 1201. useful for building a dictionary of sets:

     >>> s = [('red', 1), ('blue', 2), ('red', 3), ('blue', 4), ('red', 1), ('blue', 4)]
     >>> d = defaultdict(set)
     >>> for k, v in s:
     ...     d[k].add(v)
     ...
     >>> sorted(d.items())
     [('blue', {2, 4}), ('red', {1, 3})]


File: python.info,  Node: namedtuple Factory Function for Tuples with Named Fields,  Next: OrderedDict objects,  Prev: defaultdict objects,  Up: collections — Container datatypes

5.8.4.8 ‘namedtuple()’ Factory Function for Tuples with Named Fields
....................................................................

Named tuples assign meaning to each position in a tuple and allow for
more readable, self-documenting code.  They can be used wherever regular
tuples are used, and they add the ability to access fields by name
instead of position index.

 -- Function: collections.namedtuple (typename, field_names, *,
          rename=False, defaults=None, module=None)

     Returns a new tuple subclass named 'typename'.  The new subclass is
     used to create tuple-like objects that have fields accessible by
     attribute lookup as well as being indexable and iterable.
     Instances of the subclass also have a helpful docstring (with
     'typename' and 'field_names') and a helpful *note __repr__(): 61f.
     method which lists the tuple contents in a ‘name=value’ format.

     The 'field_names' are a sequence of strings such as ‘['x', 'y']’.
     Alternatively, 'field_names' can be a single string with each
     fieldname separated by whitespace and/or commas, for example ‘'x
     y'’ or ‘'x, y'’.

     Any valid Python identifier may be used for a fieldname except for
     names starting with an underscore.  Valid identifiers consist of
     letters, digits, and underscores but do not start with a digit or
     underscore and cannot be a *note keyword: 84. such as 'class',
     'for', 'return', 'global', 'pass', or 'raise'.

     If 'rename' is true, invalid fieldnames are automatically replaced
     with positional names.  For example, ‘['abc', 'def', 'ghi', 'abc']’
     is converted to ‘['abc', '_1', 'ghi', '_3']’, eliminating the
     keyword ‘def’ and the duplicate fieldname ‘abc’.

     'defaults' can be ‘None’ or an *note iterable: 126d. of default
     values.  Since fields with a default value must come after any
     fields without a default, the 'defaults' are applied to the
     rightmost parameters.  For example, if the fieldnames are ‘['x',
     'y', 'z']’ and the defaults are ‘(1, 2)’, then ‘x’ will be a
     required argument, ‘y’ will default to ‘1’, and ‘z’ will default to
     ‘2’.

     If 'module' is defined, the *note __module__: 377. attribute of the
     named tuple is set to that value.

     Named tuple instances do not have per-instance dictionaries, so
     they are lightweight and require no more memory than regular
     tuples.

     To support pickling, the named tuple class should be assigned to a
     variable that matches 'typename'.

     Changed in version 3.1: Added support for 'rename'.

     Changed in version 3.6: The 'verbose' and 'rename' parameters
     became *note keyword-only arguments: 2a5.

     Changed in version 3.6: Added the 'module' parameter.

     Changed in version 3.7: Removed the 'verbose' parameter and the
     ‘_source’ attribute.

     Changed in version 3.7: Added the 'defaults' parameter and the
     *note _field_defaults: 26d7. attribute.

     >>> # Basic example
     >>> Point = namedtuple('Point', ['x', 'y'])
     >>> p = Point(11, y=22)     # instantiate with positional or keyword arguments
     >>> p[0] + p[1]             # indexable like the plain tuple (11, 22)
     33
     >>> x, y = p                # unpack like a regular tuple
     >>> x, y
     (11, 22)
     >>> p.x + p.y               # fields also accessible by name
     33
     >>> p                       # readable __repr__ with a name=value style
     Point(x=11, y=22)

Named tuples are especially useful for assigning field names to result
tuples returned by the *note csv: 29. or *note sqlite3: cf. modules:

     EmployeeRecord = namedtuple('EmployeeRecord', 'name, age, title, department, paygrade')

     import csv
     for emp in map(EmployeeRecord._make, csv.reader(open("employees.csv", "rb"))):
         print(emp.name, emp.title)

     import sqlite3
     conn = sqlite3.connect('/companydata')
     cursor = conn.cursor()
     cursor.execute('SELECT name, age, title, department, paygrade FROM employees')
     for emp in map(EmployeeRecord._make, cursor.fetchall()):
         print(emp.name, emp.title)

In addition to the methods inherited from tuples, named tuples support
three additional methods and two attributes.  To prevent conflicts with
field names, the method and attribute names start with an underscore.

 -- Method: classmethod somenamedtuple._make (iterable, /)

     Class method that makes a new instance from an existing sequence or
     iterable.

          >>> t = [11, 22]
          >>> Point._make(t)
          Point(x=11, y=22)

 -- Method: somenamedtuple._asdict ()

     Return a new *note dict: 256. which maps field names to their
     corresponding values:

          >>> p = Point(x=11, y=22)
          >>> p._asdict()
          {'x': 11, 'y': 22}

     Changed in version 3.1: Returns an *note OrderedDict: 5de. instead
     of a regular *note dict: 256.

     Changed in version 3.8: Returns a regular *note dict: 256. instead
     of an *note OrderedDict: 5de.  As of Python 3.7, regular dicts are
     guaranteed to be ordered.  If the extra features of ‘OrderedDict’
     are required, the suggested remediation is to cast the result to
     the desired type: ‘OrderedDict(nt._asdict())’.

 -- Method: somenamedtuple._replace (**kwargs)

     Return a new instance of the named tuple replacing specified fields
     with new values:

          >>> p = Point(x=11, y=22)
          >>> p._replace(x=33)
          Point(x=33, y=22)

          >>> for partnum, record in inventory.items():
          ...     inventory[partnum] = record._replace(price=newprices[partnum], timestamp=time.now())

     Named tuples are also supported by generic function *note
     copy.replace(): 151.

     Changed in version 3.13: Raise *note TypeError: 2c3. instead of
     *note ValueError: 202. for invalid keyword arguments.

 -- Attribute: somenamedtuple._fields

     Tuple of strings listing the field names.  Useful for introspection
     and for creating new named tuple types from existing named tuples.

          >>> p._fields            # view the field names
          ('x', 'y')

          >>> Color = namedtuple('Color', 'red green blue')
          >>> Pixel = namedtuple('Pixel', Point._fields + Color._fields)
          >>> Pixel(11, 22, 128, 255, 0)
          Pixel(x=11, y=22, red=128, green=255, blue=0)

 -- Attribute: somenamedtuple._field_defaults

     Dictionary mapping field names to default values.

          >>> Account = namedtuple('Account', ['type', 'balance'], defaults=[0])
          >>> Account._field_defaults
          {'balance': 0}
          >>> Account('premium')
          Account(type='premium', balance=0)

To retrieve a field whose name is stored in a string, use the *note
getattr(): bf0. function:

     >>> getattr(p, 'x')
     11

To convert a dictionary to a named tuple, use the double-star-operator
(as described in *note Unpacking Argument Lists: 1dc7.):

     >>> d = {'x': 11, 'y': 22}
     >>> Point(**d)
     Point(x=11, y=22)

Since a named tuple is a regular Python class, it is easy to add or
change functionality with a subclass.  Here is how to add a calculated
field and a fixed-width print format:

     >>> class Point(namedtuple('Point', ['x', 'y'])):
     ...     __slots__ = ()
     ...     @property
     ...     def hypot(self):
     ...         return (self.x ** 2 + self.y ** 2) ** 0.5
     ...     def __str__(self):
     ...         return 'Point: x=%6.3f  y=%6.3f  hypot=%6.3f' % (self.x, self.y, self.hypot)

     >>> for p in Point(3, 4), Point(14, 5/7):
     ...     print(p)
     Point: x= 3.000  y= 4.000  hypot= 5.000
     Point: x=14.000  y= 0.714  hypot=14.018

The subclass shown above sets ‘__slots__’ to an empty tuple.  This helps
keep memory requirements low by preventing the creation of instance
dictionaries.

Subclassing is not useful for adding new, stored fields.  Instead,
simply create a new named tuple type from the *note _fields: 26da.
attribute:

     >>> Point3D = namedtuple('Point3D', Point._fields + ('z',))

Docstrings can be customized by making direct assignments to the
‘__doc__’ fields:

     >>> Book = namedtuple('Book', ['id', 'title', 'authors'])
     >>> Book.__doc__ += ': Hardcover book in active collection'
     >>> Book.id.__doc__ = '13-digit ISBN'
     >>> Book.title.__doc__ = 'Title of first printing'
     >>> Book.authors.__doc__ = 'List of authors sorted by last name'

Changed in version 3.5: Property docstrings became writeable.

See also
........

   * See *note typing.NamedTuple: 2b0. for a way to add type hints for
     named tuples.  It also provides an elegant notation using the *note
     class: 131f. keyword:

          class Component(NamedTuple):
              part_number: int
              weight: float
              description: Optional[str] = None

   * See *note types.SimpleNamespace(): 1d1. for a mutable namespace
     based on an underlying dictionary instead of a tuple.

   * The *note dataclasses: 2f. module provides a decorator and
     functions for automatically adding generated special methods to
     user-defined classes.


File: python.info,  Node: OrderedDict objects,  Next: UserDict objects,  Prev: namedtuple Factory Function for Tuples with Named Fields,  Up: collections — Container datatypes

5.8.4.9 ‘OrderedDict’ objects
.............................

Ordered dictionaries are just like regular dictionaries but have some
extra capabilities relating to ordering operations.  They have become
less important now that the built-in *note dict: 256. class gained the
ability to remember insertion order (this new behavior became guaranteed
in Python 3.7).

Some differences from *note dict: 256. still remain:

   * The regular *note dict: 256. was designed to be very good at
     mapping operations.  Tracking insertion order was secondary.

   * The *note OrderedDict: 5de. was designed to be good at reordering
     operations.  Space efficiency, iteration speed, and the performance
     of update operations were secondary.

   * The *note OrderedDict: 5de. algorithm can handle frequent
     reordering operations better than *note dict: 256.  As shown in the
     recipes below, this makes it suitable for implementing various
     kinds of LRU caches.

   * The equality operation for *note OrderedDict: 5de. checks for
     matching order.

     A regular *note dict: 256. can emulate the order sensitive equality
     test with ‘p == q and all(k1 == k2 for k1, k2 in zip(p, q))’.

   * The *note popitem(): 1336. method of *note OrderedDict: 5de. has a
     different signature.  It accepts an optional argument to specify
     which item is popped.

     A regular *note dict: 256. can emulate OrderedDict’s
     ‘od.popitem(last=True)’ with ‘d.popitem()’ which is guaranteed to
     pop the rightmost (last) item.

     A regular *note dict: 256. can emulate OrderedDict’s
     ‘od.popitem(last=False)’ with ‘(k := next(iter(d)), d.pop(k))’
     which will return and remove the leftmost (first) item if it
     exists.

   * *note OrderedDict: 5de. has a *note move_to_end(): 1224. method to
     efficiently reposition an element to an endpoint.

     A regular *note dict: 256. can emulate OrderedDict’s
     ‘od.move_to_end(k, last=True)’ with ‘d[k] = d.pop(k)’ which will
     move the key and its associated value to the rightmost (last)
     position.

     A regular *note dict: 256. does not have an efficient equivalent
     for OrderedDict’s ‘od.move_to_end(k, last=False)’ which moves the
     key and its associated value to the leftmost (first) position.

   * Until Python 3.8, *note dict: 256. lacked a *note __reversed__():
     cad. method.

 -- Class: collections.OrderedDict (**kwargs)

 -- Class: collections.OrderedDict (mapping, /, **kwargs)

 -- Class: collections.OrderedDict (iterable, /, **kwargs)

     Return an instance of a *note dict: 256. subclass that has methods
     specialized for rearranging dictionary order.

     Added in version 3.1.

      -- Method: popitem (last=True)

          The ‘popitem()’ method for ordered dictionaries returns and
          removes a (key, value) pair.  The pairs are returned in LIFO
          order if 'last' is true or FIFO (first-in, first-out) order if
          false.

      -- Method: move_to_end (key, last=True)

          Move an existing 'key' to either end of an ordered dictionary.
          The item is moved to the right end if 'last' is true (the
          default) or to the beginning if 'last' is false.  Raises *note
          KeyError: 345. if the 'key' does not exist:

               >>> d = OrderedDict.fromkeys('abcde')
               >>> d.move_to_end('b')
               >>> ''.join(d)
               'acdeb'
               >>> d.move_to_end('b', last=False)
               >>> ''.join(d)
               'bacde'

          Added in version 3.2.

In addition to the usual mapping methods, ordered dictionaries also
support reverse iteration using *note reversed(): 86c.  Equality tests
between *note OrderedDict: 5de. objects are order-sensitive and are
roughly equivalent to ‘list(od1.items())==list(od2.items())’.

Equality tests between *note OrderedDict: 5de. objects and other *note
Mapping: 8d3. objects are order-insensitive like regular dictionaries.
This allows ‘OrderedDict’ objects to be substituted anywhere a regular
dictionary is used.

Changed in version 3.5: The items, keys, and values *note views: 26dc.
of *note OrderedDict: 5de. now support reverse iteration using *note
reversed(): 86c.

Changed in version 3.6: With the acceptance of PEP 468(1), order is
retained for keyword arguments passed to the *note OrderedDict: 5de.
constructor and its *note update(): 14b4. method.

Changed in version 3.9: Added merge (‘|’) and update (‘|=’) operators,
specified in PEP 584(2).

* Menu:

* OrderedDict Examples and Recipes::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0468/

   (2) https://peps.python.org/pep-0584/


File: python.info,  Node: OrderedDict Examples and Recipes,  Up: OrderedDict objects

5.8.4.10 ‘OrderedDict’ Examples and Recipes
...........................................

It is straightforward to create an ordered dictionary variant that
remembers the order the keys were 'last' inserted.  If a new entry
overwrites an existing entry, the original insertion position is changed
and moved to the end:

     class LastUpdatedOrderedDict(OrderedDict):
         'Store items in the order the keys were last added'

         def __setitem__(self, key, value):
             super().__setitem__(key, value)
             self.move_to_end(key)

An *note OrderedDict: 5de. would also be useful for implementing
variants of *note functools.lru_cache(): 9fa.:

     from collections import OrderedDict
     from time import time

     class TimeBoundedLRU:
         "LRU Cache that invalidates and refreshes old entries."

         def __init__(self, func, maxsize=128, maxage=30):
             self.cache = OrderedDict()      # { args : (timestamp, result)}
             self.func = func
             self.maxsize = maxsize
             self.maxage = maxage

         def __call__(self, *args):
             if args in self.cache:
                 self.cache.move_to_end(args)
                 timestamp, result = self.cache[args]
                 if time() - timestamp <= self.maxage:
                     return result
             result = self.func(*args)
             self.cache[args] = time(), result
             if len(self.cache) > self.maxsize:
                 self.cache.popitem(last=False)
             return result

     class MultiHitLRUCache:
         """ LRU cache that defers caching a result until
             it has been requested multiple times.

             To avoid flushing the LRU cache with one-time requests,
             we don't cache until a request has been made more than once.

         """

         def __init__(self, func, maxsize=128, maxrequests=4096, cache_after=1):
             self.requests = OrderedDict()   # { uncached_key : request_count }
             self.cache = OrderedDict()      # { cached_key : function_result }
             self.func = func
             self.maxrequests = maxrequests  # max number of uncached requests
             self.maxsize = maxsize          # max number of stored return values
             self.cache_after = cache_after

         def __call__(self, *args):
             if args in self.cache:
                 self.cache.move_to_end(args)
                 return self.cache[args]
             result = self.func(*args)
             self.requests[args] = self.requests.get(args, 0) + 1
             if self.requests[args] <= self.cache_after:
                 self.requests.move_to_end(args)
                 if len(self.requests) > self.maxrequests:
                     self.requests.popitem(last=False)
             else:
                 self.requests.pop(args, None)
                 self.cache[args] = result
                 if len(self.cache) > self.maxsize:
                     self.cache.popitem(last=False)
             return result


File: python.info,  Node: UserDict objects,  Next: UserList objects,  Prev: OrderedDict objects,  Up: collections — Container datatypes

5.8.4.11 ‘UserDict’ objects
...........................

The class, *note UserDict: 1b26. acts as a wrapper around dictionary
objects.  The need for this class has been partially supplanted by the
ability to subclass directly from *note dict: 256.; however, this class
can be easier to work with because the underlying dictionary is
accessible as an attribute.

 -- Class: collections.UserDict (**kwargs)

 -- Class: collections.UserDict (mapping, /, **kwargs)

 -- Class: collections.UserDict (iterable, /, **kwargs)

     Class that simulates a dictionary.  The instance’s contents are
     kept in a regular dictionary, which is accessible via the *note
     data: 26df. attribute of ‘UserDict’ instances.  If arguments are
     provided, they are used to initialize ‘data’, like a regular
     dictionary.

     In addition to supporting the methods and operations of mappings,
     ‘UserDict’ instances provide the following attribute:

      -- Attribute: data

          A real dictionary used to store the contents of the ‘UserDict’
          class.


File: python.info,  Node: UserList objects,  Next: UserString objects,  Prev: UserDict objects,  Up: collections — Container datatypes

5.8.4.12 ‘UserList’ objects
...........................

This class acts as a wrapper around list objects.  It is a useful base
class for your own list-like classes which can inherit from them and
override existing methods or add new ones.  In this way, one can add new
behaviors to lists.

The need for this class has been partially supplanted by the ability to
subclass directly from *note list: 614.; however, this class can be
easier to work with because the underlying list is accessible as an
attribute.

 -- Class: collections.UserList ([list])

     Class that simulates a list.  The instance’s contents are kept in a
     regular list, which is accessible via the *note data: 26e1.
     attribute of ‘UserList’ instances.  The instance’s contents are
     initially set to a copy of 'list', defaulting to the empty list
     ‘[]’.  'list' can be any iterable, for example a real Python list
     or a ‘UserList’ object.

     In addition to supporting the methods and operations of mutable
     sequences, ‘UserList’ instances provide the following attribute:

      -- Attribute: data

          A real *note list: 614. object used to store the contents of
          the ‘UserList’ class.

'Subclassing requirements:' Subclasses of *note UserList: 1533. are
expected to offer a constructor which can be called with either no
arguments or one argument.  List operations which return a new sequence
attempt to create an instance of the actual implementation class.  To do
so, it assumes that the constructor can be called with a single
parameter, which is a sequence object used as a data source.

If a derived class does not wish to comply with this requirement, all of
the special methods supported by this class will need to be overridden;
please consult the sources for information about the methods which need
to be provided in that case.


File: python.info,  Node: UserString objects,  Prev: UserList objects,  Up: collections — Container datatypes

5.8.4.13 ‘UserString’ objects
.............................

The class, *note UserString: e03. acts as a wrapper around string
objects.  The need for this class has been partially supplanted by the
ability to subclass directly from *note str: 44f.; however, this class
can be easier to work with because the underlying string is accessible
as an attribute.

 -- Class: collections.UserString (seq)

     Class that simulates a string object.  The instance’s content is
     kept in a regular string object, which is accessible via the *note
     data: 26e3. attribute of ‘UserString’ instances.  The instance’s
     contents are initially set to a copy of 'seq'.  The 'seq' argument
     can be any object which can be converted into a string using the
     built-in *note str(): 44f. function.

     In addition to supporting the methods and operations of strings,
     ‘UserString’ instances provide the following attribute:

      -- Attribute: data

          A real *note str: 44f. object used to store the contents of
          the ‘UserString’ class.

     Changed in version 3.5: New methods ‘__getnewargs__’, ‘__rmod__’,
     ‘casefold’, ‘format_map’, ‘isprintable’, and ‘maketrans’.


File: python.info,  Node: collections abc — Abstract Base Classes for Containers,  Next: heapq — Heap queue algorithm,  Prev: collections — Container datatypes,  Up: Data Types

5.8.5 ‘collections.abc’ — Abstract Base Classes for Containers
--------------------------------------------------------------

Added in version 3.3: Formerly, this module was part of the *note
collections: 1d. module.

'Source code:' Lib/_collections_abc.py(1)

__________________________________________________________________

This module provides *note abstract base classes: 11fa. that can be used
to test whether a class provides a particular interface; for example,
whether it is *note hashable: 613. or whether it is a *note mapping:
1200.

An *note issubclass(): 7c5. or *note isinstance(): 445. test for an
interface works in one of three ways.

  1. A newly written class can inherit directly from one of the abstract
     base classes.  The class must supply the required abstract methods.
     The remaining mixin methods come from inheritance and can be
     overridden if desired.  Other methods may be added as needed:

          class C(Sequence):                      # Direct inheritance
              def __init__(self): ...             # Extra method not required by the ABC
              def __getitem__(self, index):  ...  # Required abstract method
              def __len__(self):  ...             # Required abstract method
              def count(self, value): ...         # Optionally override a mixin method

          >>> issubclass(C, Sequence)
          True
          >>> isinstance(C(), Sequence)
          True

  2. Existing classes and built-in classes can be registered as “virtual
     subclasses” of the ABCs.  Those classes should define the full API
     including all of the abstract methods and all of the mixin methods.
     This lets users rely on *note issubclass(): 7c5. or *note
     isinstance(): 445. tests to determine whether the full interface is
     supported.  The exception to this rule is for methods that are
     automatically inferred from the rest of the API:

          class D:                                 # No inheritance
              def __init__(self): ...              # Extra method not required by the ABC
              def __getitem__(self, index):  ...   # Abstract method
              def __len__(self):  ...              # Abstract method
              def count(self, value): ...          # Mixin method
              def index(self, value): ...          # Mixin method

          Sequence.register(D)                     # Register instead of inherit

          >>> issubclass(D, Sequence)
          True
          >>> isinstance(D(), Sequence)
          True

     In this example, class ‘D’ does not need to define ‘__contains__’,
     ‘__iter__’, and ‘__reversed__’ because the *note in-operator: 2228,
     the *note iteration: 126d. logic, and the *note reversed(): 86c.
     function automatically fall back to using ‘__getitem__’ and
     ‘__len__’.

  3. Some simple interfaces are directly recognizable by the presence of
     the required methods (unless those methods have been set to *note
     None: 678.):

          class E:
              def __iter__(self): ...
              def __next__(self): ...

          >>> issubclass(E, Iterable)
          True
          >>> isinstance(E(), Iterable)
          True

     Complex interfaces do not support this last technique because an
     interface is more than just the presence of method names.
     Interfaces specify semantics and relationships between methods that
     cannot be inferred solely from the presence of specific method
     names.  For example, knowing that a class supplies ‘__getitem__’,
     ‘__len__’, and ‘__iter__’ is insufficient for distinguishing a
     *note Sequence: 1209. from a *note Mapping: 8d3.

Added in version 3.9: These abstract classes now support ‘[]’.  See
*note Generic Alias Type: 6b5. and PEP 585(2).

* Menu:

* Collections Abstract Base Classes::
* Collections Abstract Base Classes – Detailed Descriptions::
* Examples and Recipes::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/_collections_abc.py

   (2) https://peps.python.org/pep-0585/


File: python.info,  Node: Collections Abstract Base Classes,  Next: Collections Abstract Base Classes – Detailed Descriptions,  Up: collections abc — Abstract Base Classes for Containers

5.8.5.1 Collections Abstract Base Classes
.........................................

The collections module offers the following *note ABCs: 11fa.:

ABC                                Inherits from              Abstract Methods            Mixin Methods
                                                                                          
---------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          
*note Container: 2407. (1)                                    ‘__contains__’
                                                              
                                                                                          
*note Hashable: 4f8. (2)                                      ‘__hash__’
                                                              
                                                                                          
*note Iterable: 2405. (3) (4)                                 ‘__iter__’
                                                              
                                                                                          
*note Iterator: 2406. (5)          *note Iterable: 2405.      ‘__next__’                  ‘__iter__’
                                                                                          
                                                                                          
*note Reversible: cac. (6)         *note Iterable: 2405.      ‘__reversed__’
                                                              
                                                                                          
*note Generator: e0b. (7)          *note Iterator: 2406.      ‘send’, ‘throw’             ‘close’, ‘__iter__’, ‘__next__’
                                                                                          
                                                                                          
*note Sized: 4f9. (8)                                         ‘__len__’
                                                              
                                                                                          
*note Callable: 7ef. (9)                                      ‘__call__’
                                                              
                                                                                          
*note Collection: cab. (10)        *note Sized: 4f9,          ‘__contains__’,
                                   *note Iterable: 2405,      ‘__iter__’, ‘__len__’
                                   *note Container: 2407.     
                                   
                                                                                          
*note Sequence: 1209.              *note Reversible: cac,     ‘__getitem__’, ‘__len__’    ‘__contains__’, ‘__iter__’, ‘__reversed__’, ‘index’,
                                   *note Collection: cab.                                 and ‘count’
                                                                                          
                                                                                          
*note MutableSequence: 1a1.        *note Sequence: 1209.      ‘__getitem__’,              Inherited *note Sequence: 1209. methods and ‘append’,
                                                              ‘__setitem__’,              ‘clear’, ‘reverse’, ‘extend’, ‘pop’, ‘remove’, and
                                                              ‘__delitem__’, ‘__len__’,   ‘__iadd__’
                                                              ‘insert’                    
                                                              
                                                                                          
*note ByteString: 2e7.             *note Sequence: 1209.      ‘__getitem__’, ‘__len__’    Inherited *note Sequence: 1209. methods
                                                                                          
                                                                                          
*note Set: 23fd.                   *note Collection: cab.     ‘__contains__’,             ‘__le__’, ‘__lt__’, ‘__eq__’, ‘__ne__’, ‘__gt__’,
                                                              ‘__iter__’, ‘__len__’       ‘__ge__’, ‘__and__’, ‘__or__’, ‘__sub__’, ‘__rsub__’,
                                                                                          ‘__xor__’, ‘__rxor__’ and ‘isdisjoint’
                                                                                          
                                                                                          
*note MutableSet: 2408.            *note Set: 23fd.           ‘__contains__’,             Inherited *note Set: 23fd. methods and ‘clear’, ‘pop’,
                                                              ‘__iter__’, ‘__len__’,      ‘remove’, ‘__ior__’, ‘__iand__’, ‘__ixor__’, and
                                                              ‘add’, ‘discard’            ‘__isub__’
                                                                                          
                                                                                          
*note Mapping: 8d3.                *note Collection: cab.     ‘__getitem__’,              ‘__contains__’, ‘keys’, ‘items’, ‘values’, ‘get’,
                                                              ‘__iter__’, ‘__len__’       ‘__eq__’, and ‘__ne__’
                                                                                          
                                                                                          
*note MutableMapping: 10f0.        *note Mapping: 8d3.        ‘__getitem__’,              Inherited *note Mapping: 8d3. methods and ‘pop’,
                                                              ‘__setitem__’,              ‘popitem’, ‘clear’, ‘update’, and ‘setdefault’
                                                              ‘__delitem__’,              
                                                              ‘__iter__’, ‘__len__’
                                                              
                                                                                          
*note MappingView: 2409.           *note Sized: 4f9.                                      ‘__init__’, ‘__len__’ and ‘__repr__’
                                                                                          
                                                                                          
*note ItemsView: 240b.             *note MappingView: 2409,                               ‘__contains__’, ‘__iter__’
                                   *note Set: 23fd.                                       
                                   
                                                                                          
*note KeysView: 240a.              *note MappingView: 2409,                               ‘__contains__’, ‘__iter__’
                                   *note Set: 23fd.                                       
                                   
                                                                                          
*note ValuesView: 240c.            *note MappingView: 2409,                               ‘__contains__’, ‘__iter__’
                                   *note Collection: cab.                                 
                                   
                                                                                          
*note Awaitable: e0c. (11)                                    ‘__await__’
                                                              
                                                                                          
*note Coroutine: e0d. (12)         *note Awaitable: e0c.      ‘send’, ‘throw’             ‘close’
                                                                                          
                                                                                          
*note AsyncIterable: e0f. (13)                                ‘__aiter__’
                                                              
                                                                                          
*note AsyncIterator: e0e. (14)     *note AsyncIterable: e0f.  ‘__anext__’                 ‘__aiter__’
                                                                                          
                                                                                          
*note AsyncGenerator: cae. (15)    *note AsyncIterator: e0e.  ‘asend’, ‘athrow’           ‘aclose’, ‘__aiter__’, ‘__anext__’
                                                                                          
                                                                                          
*note Buffer: 2e9. (16)                                       ‘__buffer__’
                                                              

   ---------- Footnotes ----------

   (1) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (2) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (3) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (4) Checking ‘isinstance(obj, Iterable)’ detects classes that are
registered as *note Iterable: 2405. or that have an *note __iter__():
1e62. method, but it does not detect classes that iterate with the *note
__getitem__(): 283. method.  The only reliable way to determine whether
an object is *note iterable: 126d. is to call ‘iter(obj)’.

   (5) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (6) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (7) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (8) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (9) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (10) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (11) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (12) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (13) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (14) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (15) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.

   (16) These ABCs override *note __subclasshook__(): 26e8. to support
testing an interface by verifying the required methods are present and
have not been set to *note None: 678.  This only works for simple
interfaces.  More complex interfaces require registration or direct
subclassing.


File: python.info,  Node: Collections Abstract Base Classes – Detailed Descriptions,  Next: Examples and Recipes,  Prev: Collections Abstract Base Classes,  Up: collections abc — Abstract Base Classes for Containers

5.8.5.2 Collections Abstract Base Classes – Detailed Descriptions
.................................................................

 -- Class: collections.abc.Container

     ABC for classes that provide the *note __contains__(): 1406.
     method.

 -- Class: collections.abc.Hashable

     ABC for classes that provide the *note __hash__(): b14. method.

 -- Class: collections.abc.Sized

     ABC for classes that provide the *note __len__(): 15da. method.

 -- Class: collections.abc.Callable

     ABC for classes that provide the *note __call__(): 55b. method.

     See *note Annotating callable objects: 2427. for details on how to
     use ‘Callable’ in type annotations.

 -- Class: collections.abc.Iterable

     ABC for classes that provide the *note __iter__(): 1e62. method.

     Checking ‘isinstance(obj, Iterable)’ detects classes that are
     registered as ‘Iterable’ or that have an *note __iter__(): 1e62.
     method, but it does not detect classes that iterate with the *note
     __getitem__(): 283. method.  The only reliable way to determine
     whether an object is *note iterable: 126d. is to call ‘iter(obj)’.

 -- Class: collections.abc.Collection

     ABC for sized iterable container classes.

     Added in version 3.6.

 -- Class: collections.abc.Iterator

     ABC for classes that provide the *note __iter__(): 1e65. and *note
     __next__(): 1315. methods.  See also the definition of *note
     iterator: 1ac.

 -- Class: collections.abc.Reversible

     ABC for iterable classes that also provide the *note
     __reversed__(): cad. method.

     Added in version 3.6.

 -- Class: collections.abc.Generator

     ABC for *note generator: 109f. classes that implement the protocol
     defined in PEP 342(1) that extends *note iterators: 1ac. with the
     *note send(): 217d, *note throw(): 4fb. and *note close(): 15df.
     methods.

     See *note Annotating generators and coroutines: 26ea. for details
     on using ‘Generator’ in type annotations.

     Added in version 3.5.

 -- Class: collections.abc.Sequence
 -- Class: collections.abc.MutableSequence
 -- Class: collections.abc.ByteString

     ABCs for read-only and mutable *note sequences: 4f4.

     Implementation note: Some of the mixin methods, such as *note
     __iter__(): 1e62, *note __reversed__(): cad, and *note index():
     2140. make repeated calls to the underlying *note __getitem__():
     283. method.  Consequently, if ‘__getitem__()’ is implemented with
     constant access speed, the mixin methods will have linear
     performance; however, if the underlying method is linear (as it
     would be with a linked list), the mixins will have quadratic
     performance and will likely need to be overridden.

      -- Method: index (value, start=0, stop=None)

          Return first index of 'value'.

          Raises *note ValueError: 202. if the value is not present.

          Supporting the 'start' and 'stop' arguments is optional, but
          recommended.

          Changed in version 3.5: The *note index(): 2140. method gained
          support for the 'stop' and 'start' arguments.

     Deprecated since version 3.12, will be removed in version 3.17: The
     ‘ByteString’ ABC has been deprecated.

     Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
     implements the *note buffer protocol: 2e8. at runtime.  For use in
     type annotations, either use *note Buffer: 2e9. or a union that
     explicitly specifies the types your code supports (e.g., ‘bytes |
     bytearray | memoryview’).

     ‘ByteString’ was originally intended to be an abstract class that
     would serve as a supertype of both *note bytes: 1c2. and *note
     bytearray: 2ea.  However, since the ABC never had any methods,
     knowing that an object was an instance of ‘ByteString’ never
     actually told you anything useful about the object.  Other common
     buffer types such as *note memoryview: 2eb. were also never
     understood as subtypes of ‘ByteString’ (either at runtime or by
     static type checkers).

     See PEP 688(2) for more details.

 -- Class: collections.abc.Set
 -- Class: collections.abc.MutableSet

     ABCs for read-only and mutable *note sets: 1de7.

 -- Class: collections.abc.Mapping
 -- Class: collections.abc.MutableMapping

     ABCs for read-only and mutable *note mappings: 1200.

 -- Class: collections.abc.MappingView
 -- Class: collections.abc.ItemsView
 -- Class: collections.abc.KeysView
 -- Class: collections.abc.ValuesView

     ABCs for mapping, items, keys, and values *note views: 26dc.

 -- Class: collections.abc.Awaitable

     ABC for *note awaitable: 1ad. objects, which can be used in *note
     await: 1b9. expressions.  Custom implementations must provide the
     *note __await__(): da3. method.

     *note Coroutine: 494. objects and instances of the *note Coroutine:
     e0d. ABC are all instances of this ABC.

          Note: In CPython, generator-based coroutines (*note
          generators: 109f. decorated with *note @types.coroutine: ebc.)
          are 'awaitables', even though they do not have an *note
          __await__(): da3. method.  Using ‘isinstance(gencoro,
          Awaitable)’ for them will return ‘False’.  Use *note
          inspect.isawaitable(): e49. to detect them.

     Added in version 3.5.

 -- Class: collections.abc.Coroutine

     ABC for *note coroutine: 494. compatible classes.  These implement
     the following methods, defined in *note Coroutine Objects: 20b8.:
     *note send(): 217c, *note throw(): 4fa, and *note close(): 217e.
     Custom implementations must also implement *note __await__(): da3.
     All ‘Coroutine’ instances are also instances of *note Awaitable:
     e0c.

          Note: In CPython, generator-based coroutines (*note
          generators: 109f. decorated with *note @types.coroutine: ebc.)
          are 'awaitables', even though they do not have an *note
          __await__(): da3. method.  Using ‘isinstance(gencoro,
          Coroutine)’ for them will return ‘False’.  Use *note
          inspect.isawaitable(): e49. to detect them.

     See *note Annotating generators and coroutines: 26ea. for details
     on using ‘Coroutine’ in type annotations.  The variance and order
     of type parameters correspond to those of *note Generator: e0b.

     Added in version 3.5.

 -- Class: collections.abc.AsyncIterable

     ABC for classes that provide an ‘__aiter__’ method.  See also the
     definition of *note asynchronous iterable: da2.

     Added in version 3.5.

 -- Class: collections.abc.AsyncIterator

     ABC for classes that provide ‘__aiter__’ and ‘__anext__’ methods.
     See also the definition of *note asynchronous iterator: 1ab.

     Added in version 3.5.

 -- Class: collections.abc.AsyncGenerator

     ABC for *note asynchronous generator: 21f2. classes that implement
     the protocol defined in PEP 525(3) and PEP 492(4).

     See *note Annotating generators and coroutines: 26ea. for details
     on using ‘AsyncGenerator’ in type annotations.

     Added in version 3.6.

 -- Class: collections.abc.Buffer

     ABC for classes that provide the *note __buffer__(): 462. method,
     implementing the *note buffer protocol: 2e8.  See PEP 688(5).

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0342/

   (2) https://peps.python.org/pep-0688/#current-options

   (3) https://peps.python.org/pep-0525/

   (4) https://peps.python.org/pep-0492/

   (5) https://peps.python.org/pep-0688/


File: python.info,  Node: Examples and Recipes,  Prev: Collections Abstract Base Classes – Detailed Descriptions,  Up: collections abc — Abstract Base Classes for Containers

5.8.5.3 Examples and Recipes
............................

ABCs allow us to ask classes or instances if they provide particular
functionality, for example:

     size = None
     if isinstance(myvar, collections.abc.Sized):
         size = len(myvar)

Several of the ABCs are also useful as mixins that make it easier to
develop classes supporting container APIs.  For example, to write a
class supporting the full *note Set: 23fd. API, it is only necessary to
supply the three underlying abstract methods: *note __contains__():
1406, *note __iter__(): 1e62, and *note __len__(): 15da.  The ABC
supplies the remaining methods such as ‘__and__()’ and *note
isdisjoint(): 23e9.:

     class ListBasedSet(collections.abc.Set):
         ''' Alternate set implementation favoring space over speed
             and not requiring the set elements to be hashable. '''
         def __init__(self, iterable):
             self.elements = lst = []
             for value in iterable:
                 if value not in lst:
                     lst.append(value)

         def __iter__(self):
             return iter(self.elements)

         def __contains__(self, value):
             return value in self.elements

         def __len__(self):
             return len(self.elements)

     s1 = ListBasedSet('abcdef')
     s2 = ListBasedSet('defghi')
     overlap = s1 & s2            # The __and__() method is supported automatically

Notes on using *note Set: 23fd. and *note MutableSet: 2408. as a mixin:

  1. Since some set operations create new sets, the default mixin
     methods need a way to create new instances from an *note iterable:
     126d.  The class constructor is assumed to have a signature in the
     form ‘ClassName(iterable)’.  That assumption is factored-out to an
     internal *note classmethod: 166. called ‘_from_iterable()’ which
     calls ‘cls(iterable)’ to produce a new set.  If the *note Set:
     23fd. mixin is being used in a class with a different constructor
     signature, you will need to override ‘_from_iterable()’ with a
     classmethod or regular method that can construct new instances from
     an iterable argument.

  2. To override the comparisons (presumably for speed, as the semantics
     are fixed), redefine *note __le__(): 1354. and *note __ge__():
     1356, then the other operations will automatically follow suit.

  3. The *note Set: 23fd. mixin provides a ‘_hash()’ method to compute a
     hash value for the set; however, *note __hash__(): b14. is not
     defined because not all sets are *note hashable: 613. or immutable.
     To add set hashability using mixins, inherit from both *note Set():
     23fd. and *note Hashable(): 4f8, then define ‘__hash__ =
     Set._hash’.

See also
........

   * OrderedSet recipe(1) for an example built on *note MutableSet:
     2408.

   * For more about ABCs, see the *note abc: 4. module and PEP 3119(2).

   ---------- Footnotes ----------

   (1) https://code.activestate.com/recipes/576694/

   (2) https://peps.python.org/pep-3119/


File: python.info,  Node: heapq — Heap queue algorithm,  Next: bisect — Array bisection algorithm,  Prev: collections abc — Abstract Base Classes for Containers,  Up: Data Types

5.8.6 ‘heapq’ — Heap queue algorithm
------------------------------------

'Source code:' Lib/heapq.py(1)

__________________________________________________________________

This module provides an implementation of the heap queue algorithm, also
known as the priority queue algorithm.

Heaps are binary trees for which every parent node has a value less than
or equal to any of its children.  We refer to this condition as the heap
invariant.

This implementation uses arrays for which ‘heap[k] <= heap[2*k+1]’ and
‘heap[k] <= heap[2*k+2]’ for all 'k', counting elements from zero.  For
the sake of comparison, non-existing elements are considered to be
infinite.  The interesting property of a heap is that its smallest
element is always the root, ‘heap[0]’.

The API below differs from textbook heap algorithms in two aspects: (a)
We use zero-based indexing.  This makes the relationship between the
index for a node and the indexes for its children slightly less obvious,
but is more suitable since Python uses zero-based indexing.  (b) Our pop
method returns the smallest item, not the largest (called a “min heap”
in textbooks; a “max heap” is more common in texts because of its
suitability for in-place sorting).

These two make it possible to view the heap as a regular Python list
without surprises: ‘heap[0]’ is the smallest item, and ‘heap.sort()’
maintains the heap invariant!

To create a heap, use a list initialized to ‘[]’, or you can transform a
populated list into a heap via function *note heapify(): 26f0.

The following functions are provided:

 -- Function: heapq.heapify (x)

     Transform list 'x' into a heap, in-place, in linear time.

 -- Function: heapq.heappush (heap, item)

     Push the value 'item' onto the 'heap', maintaining the heap
     invariant.

 -- Function: heapq.heappop (heap)

     Pop and return the smallest item from the 'heap', maintaining the
     heap invariant.  If the heap is empty, *note IndexError: 1585. is
     raised.  To access the smallest item without popping it, use
     ‘heap[0]’.

 -- Function: heapq.heappushpop (heap, item)

     Push 'item' on the heap, then pop and return the smallest item from
     the 'heap'.  The combined action runs more efficiently than *note
     heappush(): 150b. followed by a separate call to *note heappop():
     150c.

 -- Function: heapq.heapreplace (heap, item)

     Pop and return the smallest item from the 'heap', and also push the
     new 'item'.  The heap size doesn’t change.  If the heap is empty,
     *note IndexError: 1585. is raised.

     This one step operation is more efficient than a *note heappop():
     150c. followed by *note heappush(): 150b. and can be more
     appropriate when using a fixed-size heap.  The pop/push combination
     always returns an element from the heap and replaces it with
     'item'.

     The value returned may be larger than the 'item' added.  If that
     isn’t desired, consider using *note heappushpop(): 26f1. instead.
     Its push/pop combination returns the smaller of the two values,
     leaving the larger value on the heap.

The module also offers three general purpose functions based on heaps.

 -- Function: heapq.merge (*iterables, key=None, reverse=False)

     Merge multiple sorted inputs into a single sorted output (for
     example, merge timestamped entries from multiple log files).
     Returns an *note iterator: 1ac. over the sorted values.

     Similar to ‘sorted(itertools.chain(*iterables))’ but returns an
     iterable, does not pull the data into memory all at once, and
     assumes that each of the input streams is already sorted (smallest
     to largest).

     Has two optional arguments which must be specified as keyword
     arguments.

     'key' specifies a *note key function: e37. of one argument that is
     used to extract a comparison key from each input element.  The
     default value is ‘None’ (compare the elements directly).

     'reverse' is a boolean value.  If set to ‘True’, then the input
     elements are merged as if each comparison were reversed.  To
     achieve behavior similar to ‘sorted(itertools.chain(*iterables),
     reverse=True)’, all iterables must be sorted from largest to
     smallest.

     Changed in version 3.5: Added the optional 'key' and 'reverse'
     parameters.

 -- Function: heapq.nlargest (n, iterable, key=None)

     Return a list with the 'n' largest elements from the dataset
     defined by 'iterable'.  'key', if provided, specifies a function of
     one argument that is used to extract a comparison key from each
     element in 'iterable' (for example, ‘key=str.lower’).  Equivalent
     to: ‘sorted(iterable, key=key, reverse=True)[:n]’.

 -- Function: heapq.nsmallest (n, iterable, key=None)

     Return a list with the 'n' smallest elements from the dataset
     defined by 'iterable'.  'key', if provided, specifies a function of
     one argument that is used to extract a comparison key from each
     element in 'iterable' (for example, ‘key=str.lower’).  Equivalent
     to: ‘sorted(iterable, key=key)[:n]’.

The latter two functions perform best for smaller values of 'n'.  For
larger values, it is more efficient to use the *note sorted(): bed.
function.  Also, when ‘n==1’, it is more efficient to use the built-in
*note min(): f3f. and *note max(): f40. functions.  If repeated usage of
these functions is required, consider turning the iterable into an
actual heap.

* Menu:

* Basic Examples::
* Priority Queue Implementation Notes::
* Theory::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/heapq.py


File: python.info,  Node: Basic Examples,  Next: Priority Queue Implementation Notes,  Up: heapq — Heap queue algorithm

5.8.6.1 Basic Examples
......................

A heapsort(1) can be implemented by pushing all values onto a heap and
then popping off the smallest values one at a time:

     >>> def heapsort(iterable):
     ...     h = []
     ...     for value in iterable:
     ...         heappush(h, value)
     ...     return [heappop(h) for i in range(len(h))]
     ...
     >>> heapsort([1, 3, 5, 7, 9, 2, 4, 6, 8, 0])
     [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

This is similar to ‘sorted(iterable)’, but unlike *note sorted(): bed,
this implementation is not stable.

Heap elements can be tuples.  This is useful for assigning comparison
values (such as task priorities) alongside the main record being
tracked:

     >>> h = []
     >>> heappush(h, (5, 'write code'))
     >>> heappush(h, (7, 'release product'))
     >>> heappush(h, (1, 'write spec'))
     >>> heappush(h, (3, 'create tests'))
     >>> heappop(h)
     (1, 'write spec')

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Heapsort


File: python.info,  Node: Priority Queue Implementation Notes,  Next: Theory,  Prev: Basic Examples,  Up: heapq — Heap queue algorithm

5.8.6.2 Priority Queue Implementation Notes
...........................................

A priority queue(1) is common use for a heap, and it presents several
implementation challenges:

   * Sort stability: how do you get two tasks with equal priorities to
     be returned in the order they were originally added?

   * Tuple comparison breaks for (priority, task) pairs if the
     priorities are equal and the tasks do not have a default comparison
     order.

   * If the priority of a task changes, how do you move it to a new
     position in the heap?

   * Or if a pending task needs to be deleted, how do you find it and
     remove it from the queue?

A solution to the first two challenges is to store entries as 3-element
list including the priority, an entry count, and the task.  The entry
count serves as a tie-breaker so that two tasks with the same priority
are returned in the order they were added.  And since no two entry
counts are the same, the tuple comparison will never attempt to directly
compare two tasks.

Another solution to the problem of non-comparable tasks is to create a
wrapper class that ignores the task item and only compares the priority
field:

     from dataclasses import dataclass, field
     from typing import Any

     @dataclass(order=True)
     class PrioritizedItem:
         priority: int
         item: Any=field(compare=False)

The remaining challenges revolve around finding a pending task and
making changes to its priority or removing it entirely.  Finding a task
can be done with a dictionary pointing to an entry in the queue.

Removing the entry or changing its priority is more difficult because it
would break the heap structure invariants.  So, a possible solution is
to mark the entry as removed and add a new entry with the revised
priority:

     pq = []                         # list of entries arranged in a heap
     entry_finder = {}               # mapping of tasks to entries
     REMOVED = '<removed-task>'      # placeholder for a removed task
     counter = itertools.count()     # unique sequence count

     def add_task(task, priority=0):
         'Add a new task or update the priority of an existing task'
         if task in entry_finder:
             remove_task(task)
         count = next(counter)
         entry = [priority, count, task]
         entry_finder[task] = entry
         heappush(pq, entry)

     def remove_task(task):
         'Mark an existing task as REMOVED.  Raise KeyError if not found.'
         entry = entry_finder.pop(task)
         entry[-1] = REMOVED

     def pop_task():
         'Remove and return the lowest priority task. Raise KeyError if empty.'
         while pq:
             priority, count, task = heappop(pq)
             if task is not REMOVED:
                 del entry_finder[task]
                 return task
         raise KeyError('pop from an empty priority queue')

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Priority_queue


File: python.info,  Node: Theory,  Prev: Priority Queue Implementation Notes,  Up: heapq — Heap queue algorithm

5.8.6.3 Theory
..............

Heaps are arrays for which ‘a[k] <= a[2*k+1]’ and ‘a[k] <= a[2*k+2]’ for
all 'k', counting elements from 0.  For the sake of comparison,
non-existing elements are considered to be infinite.  The interesting
property of a heap is that ‘a[0]’ is always its smallest element.

The strange invariant above is meant to be an efficient memory
representation for a tournament.  The numbers below are 'k', not ‘a[k]’:

                                    0

                   1                                 2

           3               4                5               6

       7       8       9       10      11      12      13      14

     15 16   17 18   19 20   21 22   23 24   25 26   27 28   29 30

In the tree above, each cell 'k' is topping ‘2*k+1’ and ‘2*k+2’.  In a
usual binary tournament we see in sports, each cell is the winner over
the two cells it tops, and we can trace the winner down the tree to see
all opponents s/he had.  However, in many computer applications of such
tournaments, we do not need to trace the history of a winner.  To be
more memory efficient, when a winner is promoted, we try to replace it
by something else at a lower level, and the rule becomes that a cell and
the two cells it tops contain three different items, but the top cell
“wins” over the two topped cells.

If this heap invariant is protected at all time, index 0 is clearly the
overall winner.  The simplest algorithmic way to remove it and find the
“next” winner is to move some loser (let’s say cell 30 in the diagram
above) into the 0 position, and then percolate this new 0 down the tree,
exchanging values, until the invariant is re-established.  This is
clearly logarithmic on the total number of items in the tree.  By
iterating over all items, you get an 'O'('n' log 'n') sort.

A nice feature of this sort is that you can efficiently insert new items
while the sort is going on, provided that the inserted items are not
“better” than the last 0’th element you extracted.  This is especially
useful in simulation contexts, where the tree holds all incoming events,
and the “win” condition means the smallest scheduled time.  When an
event schedules other events for execution, they are scheduled into the
future, so they can easily go into the heap.  So, a heap is a good
structure for implementing schedulers (this is what I used for my MIDI
sequencer :-).

Various structures for implementing schedulers have been extensively
studied, and heaps are good for this, as they are reasonably speedy, the
speed is almost constant, and the worst case is not much different than
the average case.  However, there are other representations which are
more efficient overall, yet the worst cases might be terrible.

Heaps are also very useful in big disk sorts.  You most probably all
know that a big sort implies producing “runs” (which are pre-sorted
sequences, whose size is usually related to the amount of CPU memory),
followed by a merging passes for these runs, which merging is often very
cleverly organised (1).  It is very important that the initial sort
produces the longest runs possible.  Tournaments are a good way to
achieve that.  If, using all the memory available to hold a tournament,
you replace and percolate items that happen to fit the current run,
you’ll produce runs which are twice the size of the memory for random
input, and much better for input fuzzily ordered.

Moreover, if you output the 0’th item on disk and get an input which may
not fit in the current tournament (because the value “wins” over the
last output value), it cannot fit in the heap, so the size of the heap
decreases.  The freed memory could be cleverly reused immediately for
progressively building a second heap, which grows at exactly the same
rate the first heap is melting.  When the first heap completely
vanishes, you switch heaps and start a new run.  Clever and quite
effective!

In a word, heaps are useful memory structures to know.  I use them in a
few applications, and I think it is good to keep a ‘heap’ module around.
:-)

   ---------- Footnotes ----------

   (1) The disk balancing algorithms which are current, nowadays, are
more annoying than clever, and this is a consequence of the seeking
capabilities of the disks.  On devices which cannot seek, like big tape
drives, the story was quite different, and one had to be very clever to
ensure (far in advance) that each tape movement will be the most
effective possible (that is, will best participate at “progressing” the
merge).  Some tapes were even able to read backwards, and this was also
used to avoid the rewinding time.  Believe me, real good tape sorts were
quite spectacular to watch!  From all times, sorting has always been a
Great Art!  :-)


File: python.info,  Node: bisect — Array bisection algorithm,  Next: array — Efficient arrays of numeric values,  Prev: heapq — Heap queue algorithm,  Up: Data Types

5.8.7 ‘bisect’ — Array bisection algorithm
------------------------------------------

'Source code:' Lib/bisect.py(1)

__________________________________________________________________

This module provides support for maintaining a list in sorted order
without having to sort the list after each insertion.  For long lists of
items with expensive comparison operations, this can be an improvement
over linear searches or frequent resorting.

The module is called ‘bisect’ because it uses a basic bisection
algorithm to do its work.  Unlike other bisection tools that search for
a specific value, the functions in this module are designed to locate an
insertion point.  Accordingly, the functions never call an *note
__eq__(): b13. method to determine whether a value has been found.
Instead, the functions only call the *note __lt__(): 12e7. method and
will return an insertion point between values in an array.

     Note: The functions in this module are not thread-safe.  If
     multiple threads concurrently use ‘bisect’ functions on the same
     sequence, this may result in undefined behaviour.  Likewise, if the
     provided sequence is mutated by a different thread while a ‘bisect’
     function is operating on it, the result is undefined.  For example,
     using *note insort_left(): 26fb. on the same list from multiple
     threads may result in the list becoming unsorted.
The following functions are provided:

 -- Function: bisect.bisect_left (a, x, lo=0, hi=len(a), *, key=None)

     Locate the insertion point for 'x' in 'a' to maintain sorted order.
     The parameters 'lo' and 'hi' may be used to specify a subset of the
     list which should be considered; by default the entire list is
     used.  If 'x' is already present in 'a', the insertion point will
     be before (to the left of) any existing entries.  The return value
     is suitable for use as the first parameter to ‘list.insert()’
     assuming that 'a' is already sorted.

     The returned insertion point 'ip' partitions the array 'a' into two
     slices such that ‘all(elem < x for elem in a[lo : ip])’ is true for
     the left slice and ‘all(elem >= x for elem in a[ip : hi])’ is true
     for the right slice.

     'key' specifies a *note key function: e37. of one argument that is
     used to extract a comparison key from each element in the array.
     To support searching complex records, the key function is not
     applied to the 'x' value.

     If 'key' is ‘None’, the elements are compared directly and no key
     function is called.

     Changed in version 3.10: Added the 'key' parameter.

 -- Function: bisect.bisect_right (a, x, lo=0, hi=len(a), *, key=None)
 -- Function: bisect.bisect (a, x, lo=0, hi=len(a), *, key=None)

     Similar to *note bisect_left(): 26fd, but returns an insertion
     point which comes after (to the right of) any existing entries of
     'x' in 'a'.

     The returned insertion point 'ip' partitions the array 'a' into two
     slices such that ‘all(elem <= x for elem in a[lo : ip])’ is true
     for the left slice and ‘all(elem > x for elem in a[ip : hi])’ is
     true for the right slice.

     Changed in version 3.10: Added the 'key' parameter.

 -- Function: bisect.insort_left (a, x, lo=0, hi=len(a), *, key=None)

     Insert 'x' in 'a' in sorted order.

     This function first runs *note bisect_left(): 26fd. to locate an
     insertion point.  Next, it runs the *note insert(): 2141. method on
     'a' to insert 'x' at the appropriate position to maintain sort
     order.

     To support inserting records in a table, the 'key' function (if
     any) is applied to 'x' for the search step but not for the
     insertion step.

     Keep in mind that the 'O'(log 'n') search is dominated by the slow
     'O'('n') insertion step.

     Changed in version 3.10: Added the 'key' parameter.

 -- Function: bisect.insort_right (a, x, lo=0, hi=len(a), *, key=None)
 -- Function: bisect.insort (a, x, lo=0, hi=len(a), *, key=None)

     Similar to *note insort_left(): 26fb, but inserting 'x' in 'a'
     after any existing entries of 'x'.

     This function first runs *note bisect_right(): 26fe. to locate an
     insertion point.  Next, it runs the *note insert(): 2141. method on
     'a' to insert 'x' at the appropriate position to maintain sort
     order.

     To support inserting records in a table, the 'key' function (if
     any) is applied to 'x' for the search step but not for the
     insertion step.

     Keep in mind that the 'O'(log 'n') search is dominated by the slow
     'O'('n') insertion step.

     Changed in version 3.10: Added the 'key' parameter.

* Menu:

* Performance Notes::
* Searching Sorted Lists::
* Examples: Examples<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/bisect.py


File: python.info,  Node: Performance Notes,  Next: Searching Sorted Lists,  Up: bisect — Array bisection algorithm

5.8.7.1 Performance Notes
.........................

When writing time sensitive code using 'bisect()' and 'insort()', keep
these thoughts in mind:

   * Bisection is effective for searching ranges of values.  For
     locating specific values, dictionaries are more performant.

   * The 'insort()' functions are 'O'('n') because the logarithmic
     search step is dominated by the linear time insertion step.

   * The search functions are stateless and discard key function results
     after they are used.  Consequently, if the search functions are
     used in a loop, the key function may be called again and again on
     the same array elements.  If the key function isn’t fast, consider
     wrapping it with *note functools.cache(): 1627. to avoid duplicate
     computations.  Alternatively, consider searching an array of
     precomputed keys to locate the insertion point (as shown in the
     examples section below).

See also
........

   * Sorted Collections(1) is a high performance module that uses
     'bisect' to managed sorted collections of data.

   * The SortedCollection recipe(2) uses bisect to build a full-featured
     collection class with straight-forward search methods and support
     for a key-function.  The keys are precomputed to save unnecessary
     calls to the key function during searches.

   ---------- Footnotes ----------

   (1) https://grantjenks.com/docs/sortedcollections/

   (2) https://code.activestate.com/recipes/577197-sortedcollection/


File: python.info,  Node: Searching Sorted Lists,  Next: Examples<3>,  Prev: Performance Notes,  Up: bisect — Array bisection algorithm

5.8.7.2 Searching Sorted Lists
..............................

The above *note bisect functions: 26fc. are useful for finding insertion
points but can be tricky or awkward to use for common searching tasks.
The following five functions show how to transform them into the
standard lookups for sorted lists:

     def index(a, x):
         'Locate the leftmost value exactly equal to x'
         i = bisect_left(a, x)
         if i != len(a) and a[i] == x:
             return i
         raise ValueError

     def find_lt(a, x):
         'Find rightmost value less than x'
         i = bisect_left(a, x)
         if i:
             return a[i-1]
         raise ValueError

     def find_le(a, x):
         'Find rightmost value less than or equal to x'
         i = bisect_right(a, x)
         if i:
             return a[i-1]
         raise ValueError

     def find_gt(a, x):
         'Find leftmost value greater than x'
         i = bisect_right(a, x)
         if i != len(a):
             return a[i]
         raise ValueError

     def find_ge(a, x):
         'Find leftmost item greater than or equal to x'
         i = bisect_left(a, x)
         if i != len(a):
             return a[i]
         raise ValueError


File: python.info,  Node: Examples<3>,  Prev: Searching Sorted Lists,  Up: bisect — Array bisection algorithm

5.8.7.3 Examples
................

The *note bisect(): 26ff. function can be useful for numeric table
lookups.  This example uses ‘bisect()’ to look up a letter grade for an
exam score (say) based on a set of ordered numeric breakpoints: 90 and
up is an ‘A’, 80 to 89 is a ‘B’, and so on:

     >>> def grade(score)
     ...     i = bisect([60, 70, 80, 90], score)
     ...     return "FDCBA"[i]
     ...
     >>> [grade(score) for score in [33, 99, 77, 70, 89, 90, 100]]
     ['F', 'A', 'C', 'C', 'B', 'A', 'A']

The *note bisect(): 26ff. and *note insort(): 2701. functions also work
with lists of tuples.  The 'key' argument can serve to extract the field
used for ordering records in a table:

     >>> from collections import namedtuple
     >>> from operator import attrgetter
     >>> from bisect import bisect, insort
     >>> from pprint import pprint

     >>> Movie = namedtuple('Movie', ('name', 'released', 'director'))

     >>> movies = [
     ...     Movie('Jaws', 1975, 'Spielberg'),
     ...     Movie('Titanic', 1997, 'Cameron'),
     ...     Movie('The Birds', 1963, 'Hitchcock'),
     ...     Movie('Aliens', 1986, 'Cameron')
     ... ]

     >>> # Find the first movie released after 1960
     >>> by_year = attrgetter('released')
     >>> movies.sort(key=by_year)
     >>> movies[bisect(movies, 1960, key=by_year)]
     Movie(name='The Birds', released=1963, director='Hitchcock')

     >>> # Insert a movie while maintaining sort order
     >>> romance = Movie('Love Story', 1970, 'Hiller')
     >>> insort(movies, romance, key=by_year)
     >>> pprint(movies)
     [Movie(name='The Birds', released=1963, director='Hitchcock'),
      Movie(name='Love Story', released=1970, director='Hiller'),
      Movie(name='Jaws', released=1975, director='Spielberg'),
      Movie(name='Aliens', released=1986, director='Cameron'),
      Movie(name='Titanic', released=1997, director='Cameron')]

If the key function is expensive, it is possible to avoid repeated
function calls by searching a list of precomputed keys to find the index
of a record:

     >>> data = [('red', 5), ('blue', 1), ('yellow', 8), ('black', 0)]
     >>> data.sort(key=lambda r: r[1])       # Or use operator.itemgetter(1).
     >>> keys = [r[1] for r in data]         # Precompute a list of keys.
     >>> data[bisect_left(keys, 0)]
     ('black', 0)
     >>> data[bisect_left(keys, 1)]
     ('blue', 1)
     >>> data[bisect_left(keys, 5)]
     ('red', 5)
     >>> data[bisect_left(keys, 8)]
     ('yellow', 8)


File: python.info,  Node: array — Efficient arrays of numeric values,  Next: weakref — Weak references,  Prev: bisect — Array bisection algorithm,  Up: Data Types

5.8.8 ‘array’ — Efficient arrays of numeric values
--------------------------------------------------

__________________________________________________________________

This module defines an object type which can compactly represent an
array of basic values: characters, integers, floating-point numbers.
Arrays are mutable *note sequence: 4f4. types and behave very much like
lists, except that the type of objects stored in them is constrained.
The type is specified at object creation time by using a 'type code',
which is a single character.  The following type codes are defined:

Type code       C Type                   Python Type             Minimum size in bytes       Notes
                                                                                             
---------------------------------------------------------------------------------------------------------
                                                                                             
‘'b'’           signed char              int                     1
                                                                 
                                                                                             
‘'B'’           unsigned char            int                     1
                                                                 
                                                                                             
‘'u'’           wchar_t                  Unicode character       2                           (1)
                                                                                             
                                                                                             
‘'w'’           Py_UCS4                  Unicode character       4                           (2)
                                                                                             
                                                                                             
‘'h'’           signed short             int                     2
                                                                 
                                                                                             
‘'H'’           unsigned short           int                     2
                                                                 
                                                                                             
‘'i'’           signed int               int                     2
                                                                 
                                                                                             
‘'I'’           unsigned int             int                     2
                                                                 
                                                                                             
‘'l'’           signed long              int                     4
                                                                 
                                                                                             
‘'L'’           unsigned long            int                     4
                                                                 
                                                                                             
‘'q'’           signed long long         int                     8
                                                                 
                                                                                             
‘'Q'’           unsigned long long       int                     8
                                                                 
                                                                                             
‘'f'’           float                    float                   4
                                                                 
                                                                                             
‘'d'’           double                   float                   8
                                                                 

Notes:

  1. It can be 16 bits or 32 bits depending on the platform.

     Changed in version 3.9: ‘array('u')’ now uses ‘wchar_t’ as C type
     instead of deprecated ‘Py_UNICODE’.  This change doesn’t affect its
     behavior because ‘Py_UNICODE’ is alias of ‘wchar_t’ since Python
     3.3.

     Deprecated since version 3.3, will be removed in version 3.16:
     Please migrate to ‘'w'’ typecode.

  2. 
     Added in version 3.13.

The actual representation of values is determined by the machine
architecture (strictly speaking, by the C implementation).  The actual
size can be accessed through the *note array.itemsize: 2709. attribute.

The module defines the following item:

 -- Data: array.typecodes

     A string with all available type codes.

The module defines the following type:

 -- Class: array.array (typecode[, initializer])

     A new array whose items are restricted by 'typecode', and
     initialized from the optional 'initializer' value, which must be a
     *note bytes: 1c2. or *note bytearray: 2ea. object, a Unicode
     string, or iterable over elements of the appropriate type.

     If given a *note bytes: 1c2. or *note bytearray: 2ea. object, the
     initializer is passed to the new array’s *note frombytes(): 12b8.
     method; if given a Unicode string, the initializer is passed to the
     *note fromunicode(): 270b. method; otherwise, the initializer’s
     iterator is passed to the *note extend(): 270c. method to add
     initial items to the array.

     Array objects support the ordinary *note mutable: 231a. *note
     sequence: 4f4. operations of indexing, slicing, concatenation, and
     multiplication.  When using slice assignment, the assigned value
     must be an array object with the same type code; in all other
     cases, *note TypeError: 2c3. is raised.  Array objects also
     implement the buffer interface, and may be used wherever *note
     bytes-like objects: d55. are supported.

     Raises an *note auditing event: 1a15. ‘array.__new__’ with
     arguments ‘typecode’, ‘initializer’.

      -- Attribute: typecode

          The typecode character used to create the array.

      -- Attribute: itemsize

          The length in bytes of one array item in the internal
          representation.

      -- Method: append (value, /)

          Append a new item with the specified value to the end of the
          array.

      -- Method: buffer_info ()

          Return a tuple ‘(address, length)’ giving the current memory
          address and the length in elements of the buffer used to hold
          array’s contents.  The size of the memory buffer in bytes can
          be computed as ‘array.buffer_info()[1] * array.itemsize’.
          This is occasionally useful when working with low-level (and
          inherently unsafe) I/O interfaces that require memory
          addresses, such as certain ‘ioctl()’ operations.  The returned
          numbers are valid as long as the array exists and no
          length-changing operations are applied to it.

               Note: When using array objects from code written in C or
               C++ (the only way to effectively make use of this
               information), it makes more sense to use the buffer
               interface supported by array objects.  This method is
               maintained for backward compatibility and should be
               avoided in new code.  The buffer interface is documented
               in *note Buffer Protocol: 2e8.

      -- Method: byteswap ()

          “Byteswap” all items of the array.  This is only supported for
          values which are 1, 2, 4, or 8 bytes in size; for other types
          of values, *note RuntimeError: 195. is raised.  It is useful
          when reading data from a file written on a machine with a
          different byte order.

      -- Method: count (value, /)

          Return the number of occurrences of 'value' in the array.

      -- Method: extend (iterable, /)

          Append items from 'iterable' to the end of the array.  If
          'iterable' is another array, it must have 'exactly' the same
          type code; if not, *note TypeError: 2c3. will be raised.  If
          'iterable' is not an array, it must be iterable and its
          elements must be the right type to be appended to the array.

      -- Method: frombytes (buffer, /)

          Appends items from the *note bytes-like object: d55,
          interpreting its content as an array of machine values (as if
          it had been read from a file using the *note fromfile(): 1308.
          method).

          Added in version 3.2: ‘fromstring()’ is renamed to
          ‘frombytes()’ for clarity.

      -- Method: fromfile (f, n, /)

          Read 'n' items (as machine values) from the *note file object:
          1208. 'f' and append them to the end of the array.  If less
          than 'n' items are available, *note EOFError: 1321. is raised,
          but the items that were available are still inserted into the
          array.

      -- Method: fromlist (list, /)

          Append items from the list.  This is equivalent to ‘for x in
          list: a.append(x)’ except that if there is a type error, the
          array is unchanged.

      -- Method: fromunicode (ustr, /)

          Extends this array with data from the given Unicode string.
          The array must have type code ‘'u'’ or ‘'w'’; otherwise a
          *note ValueError: 202. is raised.  Use
          ‘array.frombytes(unicodestring.encode(enc))’ to append Unicode
          data to an array of some other type.

      -- Method: index (value[, start[, stop]])

          Return the smallest 'i' such that 'i' is the index of the
          first occurrence of 'value' in the array.  The optional
          arguments 'start' and 'stop' can be specified to search for
          'value' within a subsection of the array.  Raise *note
          ValueError: 202. if 'value' is not found.

          Changed in version 3.10: Added optional 'start' and 'stop'
          parameters.

      -- Method: insert (index, value, /)

          Insert a new item 'value' in the array before position
          'index'.  Negative values are treated as being relative to the
          end of the array.

      -- Method: pop (index=-1, /)

          Removes the item with the index 'i' from the array and returns
          it.  The optional argument defaults to ‘-1’, so that by
          default the last item is removed and returned.

      -- Method: remove (value, /)

          Remove the first occurrence of 'value' from the array.

      -- Method: clear ()

          Remove all elements from the array.

          Added in version 3.13.

      -- Method: reverse ()

          Reverse the order of the items in the array.

      -- Method: tobytes ()

          Convert the array to an array of machine values and return the
          bytes representation (the same sequence of bytes that would be
          written to a file by the *note tofile(): 1309. method.)

          Added in version 3.2: ‘tostring()’ is renamed to ‘tobytes()’
          for clarity.

      -- Method: tofile (f, /)

          Write all items (as machine values) to the *note file object:
          1208. 'f'.

      -- Method: tolist ()

          Convert the array to an ordinary list with the same items.

      -- Method: tounicode ()

          Convert the array to a Unicode string.  The array must have a
          type ‘'u'’ or ‘'w'’; otherwise a *note ValueError: 202. is
          raised.  Use ‘array.tobytes().decode(enc)’ to obtain a Unicode
          string from an array of some other type.

The string representation of array objects has the form ‘array(typecode,
initializer)’.  The 'initializer' is omitted if the array is empty,
otherwise it is a Unicode string if the 'typecode' is ‘'u'’ or ‘'w'’,
otherwise it is a list of numbers.  The string representation is
guaranteed to be able to be converted back to an array with the same
type and value using *note eval(): 180, so long as the *note array: 1a0.
class has been imported using ‘from array import array’.  Variables
‘inf’ and ‘nan’ must also be defined if it contains corresponding
floating-point values.  Examples:

     array('l')
     array('w', 'hello \u2641')
     array('l', [1, 2, 3, 4, 5])
     array('d', [1.0, 2.0, 3.14, -inf, nan])

See also
........

Module *note struct: d5.

     Packing and unpacking of heterogeneous binary data.

NumPy(1)

     The NumPy package defines another array type.

   ---------- Footnotes ----------

   (1) https://numpy.org/


File: python.info,  Node: weakref — Weak references,  Next: types — Dynamic type creation and names for built-in types,  Prev: array — Efficient arrays of numeric values,  Up: Data Types

5.8.9 ‘weakref’ — Weak references
---------------------------------

'Source code:' Lib/weakref.py(1)

__________________________________________________________________

The ‘weakref’ module allows the Python programmer to create 'weak
references' to objects.

In the following, the term 'referent' means the object which is referred
to by a weak reference.

A weak reference to an object is not enough to keep the object alive:
when the only remaining references to a referent are weak references,
*note garbage collection: 1a83. is free to destroy the referent and
reuse its memory for something else.  However, until the object is
actually destroyed the weak reference may return the object even if
there are no strong references to it.

A primary use for weak references is to implement caches or mappings
holding large objects, where it’s desired that a large object not be
kept alive solely because it appears in a cache or mapping.

For example, if you have a number of large binary image objects, you may
wish to associate a name with each.  If you used a Python dictionary to
map names to images, or images to names, the image objects would remain
alive just because they appeared as values or keys in the dictionaries.
The *note WeakKeyDictionary: 1b00. and *note WeakValueDictionary: 1aff.
classes supplied by the ‘weakref’ module are an alternative, using weak
references to construct mappings that don’t keep objects alive solely
because they appear in the mapping objects.  If, for example, an image
object is a value in a ‘WeakValueDictionary’, then when the last
remaining references to that image object are the weak references held
by weak mappings, garbage collection can reclaim the object, and its
corresponding entries in weak mappings are simply deleted.

*note WeakKeyDictionary: 1b00. and *note WeakValueDictionary: 1aff. use
weak references in their implementation, setting up callback functions
on the weak references that notify the weak dictionaries when a key or
value has been reclaimed by garbage collection.  *note WeakSet: 5e0.
implements the *note set: 5dc. interface, but keeps weak references to
its elements, just like a ‘WeakKeyDictionary’ does.

*note finalize: a8b. provides a straight forward way to register a
cleanup function to be called when an object is garbage collected.  This
is simpler to use than setting up a callback function on a raw weak
reference, since the module automatically ensures that the finalizer
remains alive until the object is collected.

Most programs should find that using one of these weak container types
or *note finalize: a8b. is all they need – it’s not usually necessary to
create your own weak references directly.  The low-level machinery is
exposed by the ‘weakref’ module for the benefit of advanced uses.

Not all objects can be weakly referenced.  Objects which support weak
references include class instances, functions written in Python (but not
in C), instance methods, sets, frozensets, some *note file objects:
1208, *note generators: 109f, type objects, sockets, arrays, deques,
regular expression pattern objects, and code objects.

Changed in version 3.2: Added support for thread.lock, threading.Lock,
and code objects.

Several built-in types such as *note list: 614. and *note dict: 256. do
not directly support weak references but can add support through
subclassing:

     class Dict(dict):
         pass

     obj = Dict(red=1, green=2, blue=3)   # this object is weak referenceable

'CPython implementation detail:' Other built-in types such as *note
tuple: 373. and *note int: 257. do not support weak references even when
subclassed.

Extension types can easily be made to support weak references; see *note
Weak Reference Support: 271c.

When ‘__slots__’ are defined for a given type, weak reference support is
disabled unless a ‘'__weakref__'’ string is also present in the sequence
of strings in the ‘__slots__’ declaration.  See *note __slots__
documentation: 20e1. for details.

 -- Class: weakref.ref (object[, callback])

     Return a weak reference to 'object'.  The original object can be
     retrieved by calling the reference object if the referent is still
     alive; if the referent is no longer alive, calling the reference
     object will cause *note None: 678. to be returned.  If 'callback'
     is provided and not ‘None’, and the returned weakref object is
     still alive, the callback will be called when the object is about
     to be finalized; the weak reference object will be passed as the
     only parameter to the callback; the referent will no longer be
     available.

     It is allowable for many weak references to be constructed for the
     same object.  Callbacks registered for each weak reference will be
     called from the most recently registered callback to the oldest
     registered callback.

     Exceptions raised by the callback will be noted on the standard
     error output, but cannot be propagated; they are handled in exactly
     the same way as exceptions raised from an object’s *note __del__():
     1038. method.

     Weak references are *note hashable: 613. if the 'object' is
     hashable.  They will maintain their hash value even after the
     'object' was deleted.  If *note hash(): 5ee. is called the first
     time only after the 'object' was deleted, the call will raise *note
     TypeError: 2c3.

     Weak references support tests for equality, but not ordering.  If
     the referents are still alive, two references have the same
     equality relationship as their referents (regardless of the
     'callback').  If either referent has been deleted, the references
     are equal only if the reference objects are the same object.

     This is a subclassable type rather than a factory function.

      -- Attribute: __callback__

          This read-only attribute returns the callback currently
          associated to the weakref.  If there is no callback or if the
          referent of the weakref is no longer alive then this attribute
          will have value ‘None’.

     Changed in version 3.4: Added the *note __callback__: 102c.
     attribute.

 -- Function: weakref.proxy (object[, callback])

     Return a proxy to 'object' which uses a weak reference.  This
     supports use of the proxy in most contexts instead of requiring the
     explicit dereferencing used with weak reference objects.  The
     returned object will have a type of either ‘ProxyType’ or
     ‘CallableProxyType’, depending on whether 'object' is callable.
     Proxy objects are not *note hashable: 613. regardless of the
     referent; this avoids a number of problems related to their
     fundamentally mutable nature, and prevents their use as dictionary
     keys.  'callback' is the same as the parameter of the same name to
     the *note ref(): 102b. function.

     Accessing an attribute of the proxy object after the referent is
     garbage collected raises *note ReferenceError: 155d.

     Changed in version 3.8: Extended the operator support on proxy
     objects to include the matrix multiplication operators ‘@’ and
     ‘@=’.

 -- Function: weakref.getweakrefcount (object)

     Return the number of weak references and proxies which refer to
     'object'.

 -- Function: weakref.getweakrefs (object)

     Return a list of all weak reference and proxy objects which refer
     to 'object'.

 -- Class: weakref.WeakKeyDictionary ([dict])

     Mapping class that references keys weakly.  Entries in the
     dictionary will be discarded when there is no longer a strong
     reference to the key.  This can be used to associate additional
     data with an object owned by other parts of an application without
     adding attributes to those objects.  This can be especially useful
     with objects that override attribute accesses.

     Note that when a key with equal value to an existing key (but not
     equal identity) is inserted into the dictionary, it replaces the
     value but does not replace the existing key.  Due to this, when the
     reference to the original key is deleted, it also deletes the entry
     in the dictionary:

          >>> class T(str): pass
          ...
          >>> k1, k2 = T(), T()
          >>> d = weakref.WeakKeyDictionary()
          >>> d[k1] = 1   # d = {k1: 1}
          >>> d[k2] = 2   # d = {k1: 2}
          >>> del k1      # d = {}

     A workaround would be to remove the key prior to reassignment:

          >>> class T(str): pass
          ...
          >>> k1, k2 = T(), T()
          >>> d = weakref.WeakKeyDictionary()
          >>> d[k1] = 1   # d = {k1: 1}
          >>> del d[k1]
          >>> d[k2] = 2   # d = {k2: 2}
          >>> del k1      # d = {k2: 2}

     Changed in version 3.9: Added support for ‘|’ and ‘|=’ operators,
     as specified in PEP 584(2).

*note WeakKeyDictionary: 1b00. objects have an additional method that
exposes the internal references directly.  The references are not
guaranteed to be “live” at the time they are used, so the result of
calling the references needs to be checked before being used.  This can
be used to avoid creating references that will cause the garbage
collector to keep the keys around longer than needed.

 -- Method: WeakKeyDictionary.keyrefs ()

     Return an iterable of the weak references to the keys.

 -- Class: weakref.WeakValueDictionary ([dict])

     Mapping class that references values weakly.  Entries in the
     dictionary will be discarded when no strong reference to the value
     exists any more.

     Changed in version 3.9: Added support for ‘|’ and ‘|=’ operators,
     as specified in PEP 584(3).

*note WeakValueDictionary: 1aff. objects have an additional method that
has the same issues as the *note WeakKeyDictionary.keyrefs(): 271f.
method.

 -- Method: WeakValueDictionary.valuerefs ()

     Return an iterable of the weak references to the values.

 -- Class: weakref.WeakSet ([elements])

     Set class that keeps weak references to its elements.  An element
     will be discarded when no strong reference to it exists any more.

 -- Class: weakref.WeakMethod (method[, callback])

     A custom *note ref: 102b. subclass which simulates a weak reference
     to a bound method (i.e., a method defined on a class and looked up
     on an instance).  Since a bound method is ephemeral, a standard
     weak reference cannot keep hold of it.  ‘WeakMethod’ has special
     code to recreate the bound method until either the object or the
     original function dies:

          >>> class C:
          ...     def method(self):
          ...         print("method called!")
          ...
          >>> c = C()
          >>> r = weakref.ref(c.method)
          >>> r()
          >>> r = weakref.WeakMethod(c.method)
          >>> r()
          <bound method C.method of <__main__.C object at 0x7fc859830220>>
          >>> r()()
          method called!
          >>> del c
          >>> gc.collect()
          0
          >>> r()
          >>>

     'callback' is the same as the parameter of the same name to the
     *note ref(): 102b. function.

     Added in version 3.4.

 -- Class: weakref.finalize (obj, func, /, *args, **kwargs)

     Return a callable finalizer object which will be called when 'obj'
     is garbage collected.  Unlike an ordinary weak reference, a
     finalizer will always survive until the reference object is
     collected, greatly simplifying lifecycle management.

     A finalizer is considered 'alive' until it is called (either
     explicitly or at garbage collection), and after that it is 'dead'.
     Calling a live finalizer returns the result of evaluating
     ‘func(*arg, **kwargs)’, whereas calling a dead finalizer returns
     *note None: 678.

     Exceptions raised by finalizer callbacks during garbage collection
     will be shown on the standard error output, but cannot be
     propagated.  They are handled in the same way as exceptions raised
     from an object’s *note __del__(): 1038. method or a weak
     reference’s callback.

     When the program exits, each remaining live finalizer is called
     unless its *note atexit: c. attribute has been set to false.  They
     are called in reverse order of creation.

     A finalizer will never invoke its callback during the later part of
     the *note interpreter shutdown: 14e. when module globals are liable
     to have been replaced by *note None: 678.

      -- Method: __call__ ()

          If 'self' is alive then mark it as dead and return the result
          of calling ‘func(*args, **kwargs)’.  If 'self' is dead then
          return *note None: 678.

      -- Method: detach ()

          If 'self' is alive then mark it as dead and return the tuple
          ‘(obj, func, args, kwargs)’.  If 'self' is dead then return
          *note None: 678.

      -- Method: peek ()

          If 'self' is alive then return the tuple ‘(obj, func, args,
          kwargs)’.  If 'self' is dead then return *note None: 678.

      -- Attribute: alive

          Property which is true if the finalizer is alive, false
          otherwise.

      -- Attribute: atexit

          A writable boolean property which by default is true.  When
          the program exits, it calls all remaining live finalizers for
          which *note atexit: 2725. is true.  They are called in reverse
          order of creation.

          Note: It is important to ensure that 'func', 'args' and
          'kwargs' do not own any references to 'obj', either directly
          or indirectly, since otherwise 'obj' will never be garbage
          collected.  In particular, 'func' should not be a bound method
          of 'obj'.

     Added in version 3.4.

 -- Data: weakref.ReferenceType

     The type object for weak references objects.

 -- Data: weakref.ProxyType

     The type object for proxies of objects which are not callable.

 -- Data: weakref.CallableProxyType

     The type object for proxies of callable objects.

 -- Data: weakref.ProxyTypes

     Sequence containing all the type objects for proxies.  This can
     make it simpler to test if an object is a proxy without being
     dependent on naming both proxy types.

See also
........

PEP 205(4) - Weak References

     The proposal and rationale for this feature, including links to
     earlier implementations and information about similar features in
     other languages.

* Menu:

* Weak Reference Objects::
* Example: Example<2>.
* Finalizer Objects::
* Comparing finalizers with __del__() methods: Comparing finalizers with __del__ methods.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/weakref.py

   (2) https://peps.python.org/pep-0584/

   (3) https://peps.python.org/pep-0584/

   (4) https://peps.python.org/pep-0205/


File: python.info,  Node: Weak Reference Objects,  Next: Example<2>,  Up: weakref — Weak references

5.8.9.1 Weak Reference Objects
..............................

Weak reference objects have no methods and no attributes besides *note
ref.__callback__: 102c.  A weak reference object allows the referent to
be obtained, if it still exists, by calling it:

     >>> import weakref
     >>> class Object:
     ...     pass
     ...
     >>> o = Object()
     >>> r = weakref.ref(o)
     >>> o2 = r()
     >>> o is o2
     True

If the referent no longer exists, calling the reference object returns
*note None: 678.:

     >>> del o, o2
     >>> print(r())
     None

Testing that a weak reference object is still live should be done using
the expression ‘ref() is not None’.  Normally, application code that
needs to use a reference object should follow this pattern:

     # r is a weak reference object
     o = r()
     if o is None:
         # referent has been garbage collected
         print("Object has been deallocated; can't frobnicate.")
     else:
         print("Object is still live!")
         o.do_something_useful()

Using a separate test for “liveness” creates race conditions in threaded
applications; another thread can cause a weak reference to become
invalidated before the weak reference is called; the idiom shown above
is safe in threaded applications as well as single-threaded
applications.

Specialized versions of *note ref: 102b. objects can be created through
subclassing.  This is used in the implementation of the *note
WeakValueDictionary: 1aff. to reduce the memory overhead for each entry
in the mapping.  This may be most useful to associate additional
information with a reference, but could also be used to insert
additional processing on calls to retrieve the referent.

This example shows how a subclass of *note ref: 102b. can be used to
store additional information about an object and affect the value that’s
returned when the referent is accessed:

     import weakref

     class ExtendedRef(weakref.ref):
         def __init__(self, ob, callback=None, /, **annotations):
             super().__init__(ob, callback)
             self.__counter = 0
             for k, v in annotations.items():
                 setattr(self, k, v)

         def __call__(self):
             """Return a pair containing the referent and the number of
             times the reference has been called.
             """
             ob = super().__call__()
             if ob is not None:
                 self.__counter += 1
                 ob = (ob, self.__counter)
             return ob


File: python.info,  Node: Example<2>,  Next: Finalizer Objects,  Prev: Weak Reference Objects,  Up: weakref — Weak references

5.8.9.2 Example
...............

This simple example shows how an application can use object IDs to
retrieve objects that it has seen before.  The IDs of the objects can
then be used in other data structures without forcing the objects to
remain alive, but the objects can still be retrieved by ID if they do.

     import weakref

     _id2obj_dict = weakref.WeakValueDictionary()

     def remember(obj):
         oid = id(obj)
         _id2obj_dict[oid] = obj
         return oid

     def id2obj(oid):
         return _id2obj_dict[oid]


File: python.info,  Node: Finalizer Objects,  Next: Comparing finalizers with __del__ methods,  Prev: Example<2>,  Up: weakref — Weak references

5.8.9.3 Finalizer Objects
.........................

The main benefit of using *note finalize: a8b. is that it makes it
simple to register a callback without needing to preserve the returned
finalizer object.  For instance

     >>> import weakref
     >>> class Object:
     ...     pass
     ...
     >>> kenny = Object()
     >>> weakref.finalize(kenny, print, "You killed Kenny!")
     <finalize object at ...; for 'Object' at ...>
     >>> del kenny
     You killed Kenny!

The finalizer can be called directly as well.  However the finalizer
will invoke the callback at most once.

     >>> def callback(x, y, z):
     ...     print("CALLBACK")
     ...     return x + y + z
     ...
     >>> obj = Object()
     >>> f = weakref.finalize(obj, callback, 1, 2, z=3)
     >>> assert f.alive
     >>> assert f() == 6
     CALLBACK
     >>> assert not f.alive
     >>> f()                     # callback not called because finalizer dead
     >>> del obj                 # callback not called because finalizer dead

You can unregister a finalizer using its *note detach(): 2722. method.
This kills the finalizer and returns the arguments passed to the
constructor when it was created.

     >>> obj = Object()
     >>> f = weakref.finalize(obj, callback, 1, 2, z=3)
     >>> f.detach()
     (<...Object object ...>, <function callback ...>, (1, 2), {'z': 3})
     >>> newobj, func, args, kwargs = _
     >>> assert not f.alive
     >>> assert newobj is obj
     >>> assert func(*args, **kwargs) == 6
     CALLBACK

Unless you set the *note atexit: 2725. attribute to *note False: b4f, a
finalizer will be called when the program exits if it is still alive.
For instance

     >>> obj = Object()
     >>> weakref.finalize(obj, print, "obj dead or exiting")
     <finalize object at ...; for 'Object' at ...>
     >>> exit()
     obj dead or exiting


File: python.info,  Node: Comparing finalizers with __del__ methods,  Prev: Finalizer Objects,  Up: weakref — Weak references

5.8.9.4 Comparing finalizers with ‘__del__()’ methods
.....................................................

Suppose we want to create a class whose instances represent temporary
directories.  The directories should be deleted with their contents when
the first of the following events occurs:

   * the object is garbage collected,

   * the object’s ‘remove()’ method is called, or

   * the program exits.

We might try to implement the class using a *note __del__(): 1038.
method as follows:

     class TempDir:
         def __init__(self):
             self.name = tempfile.mkdtemp()

         def remove(self):
             if self.name is not None:
                 shutil.rmtree(self.name)
                 self.name = None

         @property
         def removed(self):
             return self.name is None

         def __del__(self):
             self.remove()

Starting with Python 3.4, *note __del__(): 1038. methods no longer
prevent reference cycles from being garbage collected, and module
globals are no longer forced to *note None: 678. during *note
interpreter shutdown: 14e.  So this code should work without any issues
on CPython.

However, handling of *note __del__(): 1038. methods is notoriously
implementation specific, since it depends on internal details of the
interpreter’s garbage collector implementation.

A more robust alternative can be to define a finalizer which only
references the specific functions and objects that it needs, rather than
having access to the full state of the object:

     class TempDir:
         def __init__(self):
             self.name = tempfile.mkdtemp()
             self._finalizer = weakref.finalize(self, shutil.rmtree, self.name)

         def remove(self):
             self._finalizer()

         @property
         def removed(self):
             return not self._finalizer.alive

Defined like this, our finalizer only receives a reference to the
details it needs to clean up the directory appropriately.  If the object
never gets garbage collected the finalizer will still be called at exit.

The other advantage of weakref based finalizers is that they can be used
to register finalizers for classes where the definition is controlled by
a third party, such as running code when a module is unloaded:

     import weakref, sys
     def unloading_module():
         # implicit reference to the module globals from the function body
     weakref.finalize(sys.modules[__name__], unloading_module)

     Note: If you create a finalizer object in a daemonic thread just as
     the program exits then there is the possibility that the finalizer
     does not get called at exit.  However, in a daemonic thread *note
     atexit.register(): 885, ‘try: ... finally: ...’ and ‘with: ...’ do
     not guarantee that cleanup occurs either.


File: python.info,  Node: types — Dynamic type creation and names for built-in types,  Next: copy — Shallow and deep copy operations,  Prev: weakref — Weak references,  Up: Data Types

5.8.10 ‘types’ — Dynamic type creation and names for built-in types
-------------------------------------------------------------------

'Source code:' Lib/types.py(1)

__________________________________________________________________

This module defines utility functions to assist in dynamic creation of
new types.

It also defines names for some object types that are used by the
standard Python interpreter, but not exposed as builtins like *note int:
257. or *note str: 44f. are.

Finally, it provides some additional type-related utility classes and
functions that are not fundamental enough to be builtins.

* Menu:

* Dynamic Type Creation::
* Standard Interpreter Types::
* Additional Utility Classes and Functions::
* Coroutine Utility Functions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/types.py


File: python.info,  Node: Dynamic Type Creation,  Next: Standard Interpreter Types,  Up: types — Dynamic type creation and names for built-in types

5.8.10.1 Dynamic Type Creation
..............................

 -- Function: types.new_class (name, bases=(), kwds=None,
          exec_body=None)

     Creates a class object dynamically using the appropriate metaclass.

     The first three arguments are the components that make up a class
     definition header: the class name, the base classes (in order), the
     keyword arguments (such as ‘metaclass’).

     The 'exec_body' argument is a callback that is used to populate the
     freshly created class namespace.  It should accept the class
     namespace as its sole argument and update the namespace directly
     with the class contents.  If no callback is provided, it has the
     same effect as passing in ‘lambda ns: None’.

     Added in version 3.3.

 -- Function: types.prepare_class (name, bases=(), kwds=None)

     Calculates the appropriate metaclass and creates the class
     namespace.

     The arguments are the components that make up a class definition
     header: the class name, the base classes (in order) and the keyword
     arguments (such as ‘metaclass’).

     The return value is a 3-tuple: ‘metaclass, namespace, kwds’

     'metaclass' is the appropriate metaclass, 'namespace' is the
     prepared class namespace and 'kwds' is an updated copy of the
     passed in 'kwds' argument with any ‘'metaclass'’ entry removed.  If
     no 'kwds' argument is passed in, this will be an empty dict.

     Added in version 3.3.

     Changed in version 3.6: The default value for the ‘namespace’
     element of the returned tuple has changed.  Now an
     insertion-order-preserving mapping is used when the metaclass does
     not have a ‘__prepare__’ method.

See also
........

*note Metaclasses: 2124.

     Full details of the class creation process supported by these
     functions

PEP 3115(1) - Metaclasses in Python 3000

     Introduced the ‘__prepare__’ namespace hook

 -- Function: types.resolve_bases (bases)

     Resolve MRO entries dynamically as specified by PEP 560(2).

     This function looks for items in 'bases' that are not instances of
     *note type: d71, and returns a tuple where each such object that
     has an *note __mro_entries__(): b02. method is replaced with an
     unpacked result of calling this method.  If a 'bases' item is an
     instance of ‘type’, or it doesn’t have an ‘__mro_entries__()’
     method, then it is included in the return tuple unchanged.

     Added in version 3.7.

 -- Function: types.get_original_bases (cls, /)

     Return the tuple of objects originally given as the bases of 'cls'
     before the *note __mro_entries__(): b02. method has been called on
     any bases (following the mechanisms laid out in PEP 560(3)).  This
     is useful for introspecting *note Generics: 4d2.

     For classes that have an ‘__orig_bases__’ attribute, this function
     returns the value of ‘cls.__orig_bases__’.  For classes without the
     ‘__orig_bases__’ attribute, *note cls.__bases__: 14fb. is returned.

     Examples:

          from typing import TypeVar, Generic, NamedTuple, TypedDict

          T = TypeVar("T")
          class Foo(Generic[T]): ...
          class Bar(Foo[int], float): ...
          class Baz(list[str]): ...
          Eggs = NamedTuple("Eggs", [("a", int), ("b", str)])
          Spam = TypedDict("Spam", {"a": int, "b": str})

          assert Bar.__bases__ == (Foo, float)
          assert get_original_bases(Bar) == (Foo[int], float)

          assert Baz.__bases__ == (list,)
          assert get_original_bases(Baz) == (list[str],)

          assert Eggs.__bases__ == (tuple,)
          assert get_original_bases(Eggs) == (NamedTuple,)

          assert Spam.__bases__ == (dict,)
          assert get_original_bases(Spam) == (TypedDict,)

          assert int.__bases__ == (object,)
          assert get_original_bases(int) == (object,)

     Added in version 3.12.

See also
........

PEP 560(4) - Core support for typing module and generic types

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3115/

   (2) https://peps.python.org/pep-0560/

   (3) https://peps.python.org/pep-0560/

   (4) https://peps.python.org/pep-0560/


File: python.info,  Node: Standard Interpreter Types,  Next: Additional Utility Classes and Functions,  Prev: Dynamic Type Creation,  Up: types — Dynamic type creation and names for built-in types

5.8.10.2 Standard Interpreter Types
...................................

This module provides names for many of the types that are required to
implement a Python interpreter.  It deliberately avoids including some
of the types that arise only incidentally during processing such as the
‘listiterator’ type.

Typical use of these names is for *note isinstance(): 445. or *note
issubclass(): 7c5. checks.

If you instantiate any of these types, note that signatures may vary
between Python versions.

Standard names are defined for the following types:

 -- Data: types.NoneType

     The type of *note None: 678.

     Added in version 3.10.

 -- Data: types.FunctionType
 -- Data: types.LambdaType

     The type of user-defined functions and functions created by *note
     lambda: 12e4. expressions.

     Raises an *note auditing event: 1a15. ‘function.__new__’ with
     argument ‘code’.

     The audit event only occurs for direct instantiation of function
     objects, and is not raised for normal compilation.

 -- Data: types.GeneratorType

     The type of *note generator: 109f.-iterator objects, created by
     generator functions.

 -- Data: types.CoroutineType

     The type of *note coroutine: 494. objects, created by *note async
     def: 5d4. functions.

     Added in version 3.5.

 -- Data: types.AsyncGeneratorType

     The type of *note asynchronous generator: 21f2.-iterator objects,
     created by asynchronous generator functions.

     Added in version 3.6.

 -- Class: types.CodeType (**kwargs)

     The type of *note code objects: 1d2. such as returned by *note
     compile(): 192.

     Raises an *note auditing event: 1a15. ‘code.__new__’ with arguments
     ‘code’, ‘filename’, ‘name’, ‘argcount’, ‘posonlyargcount’,
     ‘kwonlyargcount’, ‘nlocals’, ‘stacksize’, ‘flags’.

     Note that the audited arguments may not match the names or
     positions required by the initializer.  The audit event only occurs
     for direct instantiation of code objects, and is not raised for
     normal compilation.

 -- Data: types.CellType

     The type for cell objects: such objects are used as containers for
     a function’s *note closure variables: 20f4.

     Added in version 3.8.

 -- Data: types.MethodType

     The type of methods of user-defined class instances.

 -- Data: types.BuiltinFunctionType
 -- Data: types.BuiltinMethodType

     The type of built-in functions like *note len(): 631. or *note
     sys.exit(): 1394, and methods of built-in classes.  (Here, the term
     “built-in” means “written in C”.)

 -- Data: types.WrapperDescriptorType

     The type of methods of some built-in data types and base classes
     such as *note object.__init__(): 6b3. or *note object.__lt__():
     12e7.

     Added in version 3.7.

 -- Data: types.MethodWrapperType

     The type of 'bound' methods of some built-in data types and base
     classes.  For example it is the type of ‘object().__str__’.

     Added in version 3.7.

 -- Data: types.NotImplementedType

     The type of *note NotImplemented: 7d6.

     Added in version 3.10.

 -- Data: types.MethodDescriptorType

     The type of methods of some built-in data types such as *note
     str.join(): 2363.

     Added in version 3.7.

 -- Data: types.ClassMethodDescriptorType

     The type of 'unbound' class methods of some built-in data types
     such as ‘dict.__dict__['fromkeys']’.

     Added in version 3.7.

 -- Class: types.ModuleType (name, doc=None)

     The type of *note modules: 1772.  The constructor takes the name of
     the module to be created and optionally its *note docstring: 22e0.

     See also
     ........

     *note Documentation on module objects: 20c0.

          Provides details on the special attributes that can be found
          on instances of ‘ModuleType’.

     *note importlib.util.module_from_spec(): e44.

          Modules created using the ‘ModuleType’ constructor are created
          with many of their special attributes unset or set to default
          values.  ‘module_from_spec()’ provides a more robust way of
          creating ‘ModuleType’ instances which ensures the various
          attributes are set appropriately.

 -- Data: types.EllipsisType

     The type of *note Ellipsis: 233f.

     Added in version 3.10.

 -- Class: types.GenericAlias (t_origin, t_args)

     The type of *note parameterized generics: 6b5. such as ‘list[int]’.

     ‘t_origin’ should be a non-parameterized generic class, such as
     ‘list’, ‘tuple’ or ‘dict’.  ‘t_args’ should be a *note tuple: 373.
     (possibly of length 1) of types which parameterize ‘t_origin’:

          >>> from types import GenericAlias

          >>> list[int] == GenericAlias(list, (int,))
          True
          >>> dict[str, int] == GenericAlias(dict, (str, int))
          True

     Added in version 3.9.

     Changed in version 3.9.2: This type can now be subclassed.

     See also
     ........

     *note Generic Alias Types: 6b5.

          In-depth documentation on instances of ‘types.GenericAlias’

     PEP 585(1) - Type Hinting Generics In Standard Collections

          Introducing the ‘types.GenericAlias’ class

 -- Class: types.UnionType

     The type of *note union type expressions: 7c6.

     Added in version 3.10.

 -- Class: types.TracebackType (tb_next, tb_frame, tb_lasti, tb_lineno)

     The type of traceback objects such as found in
     ‘sys.exception().__traceback__’.

     See *note the language reference: b0d. for details of the available
     attributes and operations, and guidance on creating tracebacks
     dynamically.

 -- Data: types.FrameType

     The type of *note frame objects: 6e3. such as found in *note
     tb.tb_frame: 2107. if ‘tb’ is a traceback object.

 -- Data: types.GetSetDescriptorType

     The type of objects defined in extension modules with
     ‘PyGetSetDef’, such as *note FrameType.f_locals: 182. or
     ‘array.array.typecode’.  This type is used as descriptor for object
     attributes; it has the same purpose as the *note property: 194.
     type, but for classes defined in extension modules.

 -- Data: types.MemberDescriptorType

     The type of objects defined in extension modules with
     ‘PyMemberDef’, such as ‘datetime.timedelta.days’.  This type is
     used as descriptor for simple C data members which use standard
     conversion functions; it has the same purpose as the *note
     property: 194. type, but for classes defined in extension modules.

     In addition, when a class is defined with a *note __slots__: 153a.
     attribute, then for each slot, an instance of
     ‘MemberDescriptorType’ will be added as an attribute on the class.
     This allows the slot to appear in the class’s *note __dict__: c7e.

     'CPython implementation detail:' In other implementations of
     Python, this type may be identical to ‘GetSetDescriptorType’.

 -- Class: types.MappingProxyType (mapping)

     Read-only proxy of a mapping.  It provides a dynamic view on the
     mapping’s entries, which means that when the mapping changes, the
     view reflects these changes.

     Added in version 3.3.

     Changed in version 3.9: Updated to support the new union (‘|’)
     operator from PEP 584(2), which simply delegates to the underlying
     mapping.

      -- Describe: key in proxy

          Return ‘True’ if the underlying mapping has a key 'key', else
          ‘False’.

      -- Describe: proxy[key]

          Return the item of the underlying mapping with key 'key'.
          Raises a *note KeyError: 345. if 'key' is not in the
          underlying mapping.

      -- Describe: iter(proxy)

          Return an iterator over the keys of the underlying mapping.
          This is a shortcut for ‘iter(proxy.keys())’.

      -- Describe: len(proxy)

          Return the number of items in the underlying mapping.

      -- Method: copy ()

          Return a shallow copy of the underlying mapping.

      -- Method: get (key[, default])

          Return the value for 'key' if 'key' is in the underlying
          mapping, else 'default'.  If 'default' is not given, it
          defaults to ‘None’, so that this method never raises a *note
          KeyError: 345.

      -- Method: items ()

          Return a new view of the underlying mapping’s items (‘(key,
          value)’ pairs).

      -- Method: keys ()

          Return a new view of the underlying mapping’s keys.

      -- Method: values ()

          Return a new view of the underlying mapping’s values.

      -- Describe: reversed(proxy)

          Return a reverse iterator over the keys of the underlying
          mapping.

          Added in version 3.9.

      -- Describe: hash(proxy)

          Return a hash of the underlying mapping.

          Added in version 3.12.

 -- Class: types.CapsuleType

     The type of *note capsule objects: 2740.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0584/


File: python.info,  Node: Additional Utility Classes and Functions,  Next: Coroutine Utility Functions,  Prev: Standard Interpreter Types,  Up: types — Dynamic type creation and names for built-in types

5.8.10.3 Additional Utility Classes and Functions
.................................................

 -- Class: types.SimpleNamespace

     A simple *note object: a9b. subclass that provides attribute access
     to its namespace, as well as a meaningful repr.

     Unlike *note object: a9b, with ‘SimpleNamespace’ you can add and
     remove attributes.

     ‘SimpleNamespace’ objects may be initialized in the same way as
     *note dict: 256.: either with keyword arguments, with a single
     positional argument, or with both.  When initialized with keyword
     arguments, those are directly added to the underlying namespace.
     Alternatively, when initialized with a positional argument, the
     underlying namespace will be updated with key-value pairs from that
     argument (either a mapping object or an *note iterable: 126d.
     object producing key-value pairs).  All such keys must be strings.

     The type is roughly equivalent to the following code:

          class SimpleNamespace:
              def __init__(self, mapping_or_iterable=(), /, **kwargs):
                  self.__dict__.update(mapping_or_iterable)
                  self.__dict__.update(kwargs)

              def __repr__(self):
                  items = (f"{k}={v!r}" for k, v in self.__dict__.items())
                  return "{}({})".format(type(self).__name__, ", ".join(items))

              def __eq__(self, other):
                  if isinstance(self, SimpleNamespace) and isinstance(other, SimpleNamespace):
                     return self.__dict__ == other.__dict__
                  return NotImplemented

     ‘SimpleNamespace’ may be useful as a replacement for ‘class NS:
     pass’.  However, for a structured record type use *note
     namedtuple(): 1ca. instead.

     ‘SimpleNamespace’ objects are supported by *note copy.replace():
     151.

     Added in version 3.3.

     Changed in version 3.9: Attribute order in the repr changed from
     alphabetical to insertion (like ‘dict’).

     Changed in version 3.13: Added support for an optional positional
     argument.

 -- Function: types.DynamicClassAttribute (fget=None, fset=None,
          fdel=None, doc=None)

     Route attribute access on a class to __getattr__.

     This is a descriptor, used to define attributes that act
     differently when accessed through an instance and through a class.
     Instance access remains normal, but access to an attribute through
     a class will be routed to the class’s __getattr__ method; this is
     done by raising AttributeError.

     This allows one to have properties active on an instance, and have
     virtual attributes on the class with the same name (see *note
     enum.Enum: 633. for an example).

     Added in version 3.4.


File: python.info,  Node: Coroutine Utility Functions,  Prev: Additional Utility Classes and Functions,  Up: types — Dynamic type creation and names for built-in types

5.8.10.4 Coroutine Utility Functions
....................................

 -- Function: types.coroutine (gen_func)

     This function transforms a *note generator: 109f. function into a
     *note coroutine function: da1. which returns a generator-based
     coroutine.  The generator-based coroutine is still a *note
     generator iterator: bff, but is also considered to be a *note
     coroutine: 494. object and is *note awaitable: 1ad.  However, it
     may not necessarily implement the *note __await__(): da3. method.

     If 'gen_func' is a generator function, it will be modified
     in-place.

     If 'gen_func' is not a generator function, it will be wrapped.  If
     it returns an instance of *note collections.abc.Generator: e0b, the
     instance will be wrapped in an 'awaitable' proxy object.  All other
     types of objects will be returned as is.

     Added in version 3.5.


File: python.info,  Node: copy — Shallow and deep copy operations,  Next: pprint — Data pretty printer,  Prev: types — Dynamic type creation and names for built-in types,  Up: Data Types

5.8.11 ‘copy’ — Shallow and deep copy operations
------------------------------------------------

'Source code:' Lib/copy.py(1)

__________________________________________________________________

Assignment statements in Python do not copy objects, they create
bindings between a target and an object.  For collections that are
mutable or contain mutable items, a copy is sometimes needed so one can
change one copy without changing the other.  This module provides
generic shallow and deep copy operations (explained below).

Interface summary:

 -- Function: copy.copy (obj)

     Return a shallow copy of 'obj'.

 -- Function: copy.deepcopy (obj[, memo])

     Return a deep copy of 'obj'.

 -- Function: copy.replace (obj, /, **changes)

     Creates a new object of the same type as 'obj', replacing fields
     with values from 'changes'.

     Added in version 3.13.

 -- Exception: copy.Error

     Raised for module specific errors.
The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances):

   * A 'shallow copy' constructs a new compound object and then (to the
     extent possible) inserts 'references' into it to the objects found
     in the original.

   * A 'deep copy' constructs a new compound object and then,
     recursively, inserts 'copies' into it of the objects found in the
     original.

Two problems often exist with deep copy operations that don’t exist with
shallow copy operations:

   * Recursive objects (compound objects that, directly or indirectly,
     contain a reference to themselves) may cause a recursive loop.

   * Because deep copy copies everything it may copy too much, such as
     data which is intended to be shared between copies.

The *note deepcopy(): b8a. function avoids these problems by:

   * keeping a ‘memo’ dictionary of objects already copied during the
     current copying pass; and

   * letting user-defined classes override the copying operation or the
     set of components copied.

This module does not copy types like module, method, stack trace, stack
frame, file, socket, window, or any similar types.  It does “copy”
functions and classes (shallow and deeply), by returning the original
object unchanged; this is compatible with the way these are treated by
the *note pickle: a6. module.

Shallow copies of dictionaries can be made using *note dict.copy(): bef,
and of lists by assigning a slice of the entire list, for example,
‘copied_list = original_list[:]’.

Classes can use the same interfaces to control copying that they use to
control pickling.  See the description of module *note pickle: a6. for
information on these methods.  In fact, the ‘copy’ module uses the
registered pickle functions from the *note copyreg: 26. module.

In order for a class to define its own copy implementation, it can
define special methods *note __copy__(): 161d. and *note __deepcopy__():
161e.

 -- Method: object.__copy__ (self)

     Called to implement the shallow copy operation; no additional
     arguments are passed.

 -- Method: object.__deepcopy__ (self, memo)

     Called to implement the deep copy operation; it is passed one
     argument, the 'memo' dictionary.  If the ‘__deepcopy__’
     implementation needs to make a deep copy of a component, it should
     call the *note deepcopy(): b8a. function with the component as
     first argument and the 'memo' dictionary as second argument.  The
     'memo' dictionary should be treated as an opaque object.

Function ‘copy.replace()’ is more limited than *note copy(): 537. and
*note deepcopy(): b8a, and only supports named tuples created by *note
namedtuple(): 1ca, *note dataclasses: 2f, and other classes which define
method *note __replace__(): 152.

 -- Method: object.__replace__ (self, /, **changes)

     This method should create a new object of the same type, replacing
     fields with values from 'changes'.

     Added in version 3.13.

See also
........

Module *note pickle: a6.

     Discussion of the special methods used to support object state
     retrieval and restoration.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/copy.py


File: python.info,  Node: pprint — Data pretty printer,  Next: reprlib — Alternate repr implementation,  Prev: copy — Shallow and deep copy operations,  Up: Data Types

5.8.12 ‘pprint’ — Data pretty printer
-------------------------------------

'Source code:' Lib/pprint.py(1)

__________________________________________________________________

The ‘pprint’ module provides a capability to “pretty-print” arbitrary
Python data structures in a form which can be used as input to the
interpreter.  If the formatted structures include objects which are not
fundamental Python types, the representation may not be loadable.  This
may be the case if objects such as files, sockets or classes are
included, as well as many other objects which are not representable as
Python literals.

The formatted representation keeps objects on a single line if it can,
and breaks them onto multiple lines if they don’t fit within the allowed
width, adjustable by the 'width' parameter defaulting to 80 characters.

Changed in version 3.9: Added support for pretty-printing *note
types.SimpleNamespace: 1d1.

Changed in version 3.10: Added support for pretty-printing *note
dataclasses.dataclass: 1cb.

* Menu:

* Functions: Functions<4>.
* PrettyPrinter Objects::
* Example: Example<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pprint.py


File: python.info,  Node: Functions<4>,  Next: PrettyPrinter Objects,  Up: pprint — Data pretty printer

5.8.12.1 Functions
..................

 -- Function: pprint.pp (object, stream=None, indent=1, width=80,
          depth=None, *, compact=False, sort_dicts=False,
          underscore_numbers=False)

     Prints the formatted representation of 'object', followed by a
     newline.  This function may be used in the interactive interpreter
     instead of the *note print(): fae. function for inspecting values.
     Tip: you can reassign ‘print = pprint.pp’ for use within a scope.


     Parameters:

        * ‘object’ – The object to be printed.

        * ‘stream’ (*note file-like object: 15f4. | None) – A file-like
          object to which the output will be written by calling its
          ‘write()’ method.  If ‘None’ (the default), *note sys.stdout:
          aec. is used.

        * ‘indent’ (*note int: 257.) – The amount of indentation added
          for each nesting level.

        * ‘width’ (*note int: 257.) – The desired maximum number of
          characters per line in the output.  If a structure cannot be
          formatted within the width constraint, a best effort will be
          made.

        * ‘depth’ (*note int: 257.‘ | ’‘None’) – The number of nesting
          levels which may be printed.  If the data structure being
          printed is too deep, the next contained level is replaced by
          ‘...’.  If ‘None’ (the default), there is no constraint on the
          depth of the objects being formatted.

        * ‘compact’ (*note bool: 46b.) – Control the way long *note
          sequences: 4f4. are formatted.  If ‘False’ (the default), each
          item of a sequence will be formatted on a separate line,
          otherwise as many items as will fit within the 'width' will be
          formatted on each output line.

        * ‘sort_dicts’ (*note bool: 46b.) – If ‘True’, dictionaries will
          be formatted with their keys sorted, otherwise they will be
          displayed in insertion order (the default).

        * ‘underscore_numbers’ (*note bool: 46b.) – If ‘True’, integers
          will be formatted with the ‘_’ character for a thousands
          separator, otherwise underscores are not displayed (the
          default).

          >>> import pprint
          >>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
          >>> stuff.insert(0, stuff)
          >>> pprint.pp(stuff)
          [<Recursion on list with id=...>,
           'spam',
           'eggs',
           'lumberjack',
           'knights',
           'ni']

     Added in version 3.8.

 -- Function: pprint.pprint (object, stream=None, indent=1, width=80,
          depth=None, *, compact=False, sort_dicts=True,
          underscore_numbers=False)

     Alias for *note pp(): a30. with 'sort_dicts' set to ‘True’ by
     default, which would automatically sort the dictionaries’ keys, you
     might want to use ‘pp()’ instead where it is ‘False’ by default.

 -- Function: pprint.pformat (object, indent=1, width=80, depth=None, *,
          compact=False, sort_dicts=True, underscore_numbers=False)

     Return the formatted representation of 'object' as a string.
     'indent', 'width', 'depth', 'compact', 'sort_dicts' and
     'underscore_numbers' are passed to the *note PrettyPrinter: fb8.
     constructor as formatting parameters and their meanings are as
     described in the documentation above.

 -- Function: pprint.isreadable (object)

     Determine if the formatted representation of 'object' is
     “readable”, or can be used to reconstruct the value using *note
     eval(): 180.  This always returns ‘False’ for recursive objects.

          >>> pprint.isreadable(stuff)
          False

 -- Function: pprint.isrecursive (object)

     Determine if 'object' requires a recursive representation.  This
     function is subject to the same limitations as noted in *note
     saferepr(): 274e. below and may raise an *note RecursionError: d96.
     if it fails to detect a recursive object.

 -- Function: pprint.saferepr (object)

     Return a string representation of 'object', protected against
     recursion in some common data structures, namely instances of *note
     dict: 256, *note list: 614. and *note tuple: 373. or subclasses
     whose ‘__repr__’ has not been overridden.  If the representation of
     object exposes a recursive entry, the recursive reference will be
     represented as ‘<Recursion on typename with id=number>’.  The
     representation is not otherwise formatted.

          >>> pprint.saferepr(stuff)
          "[<Recursion on list with id=...>, 'spam', 'eggs', 'lumberjack', 'knights', 'ni']"


File: python.info,  Node: PrettyPrinter Objects,  Next: Example<3>,  Prev: Functions<4>,  Up: pprint — Data pretty printer

5.8.12.2 PrettyPrinter Objects
..............................

 -- Class: pprint.PrettyPrinter (indent=1, width=80, depth=None,
          stream=None, *, compact=False, sort_dicts=True,
          underscore_numbers=False)

     Construct a ‘PrettyPrinter’ instance.

     Arguments have the same meaning as for *note pp(): a30.  Note that
     they are in a different order, and that 'sort_dicts' defaults to
     ‘True’.

          >>> import pprint
          >>> stuff = ['spam', 'eggs', 'lumberjack', 'knights', 'ni']
          >>> stuff.insert(0, stuff[:])
          >>> pp = pprint.PrettyPrinter(indent=4)
          >>> pp.pprint(stuff)
          [   ['spam', 'eggs', 'lumberjack', 'knights', 'ni'],
              'spam',
              'eggs',
              'lumberjack',
              'knights',
              'ni']
          >>> pp = pprint.PrettyPrinter(width=41, compact=True)
          >>> pp.pprint(stuff)
          [['spam', 'eggs', 'lumberjack',
            'knights', 'ni'],
           'spam', 'eggs', 'lumberjack', 'knights',
           'ni']
          >>> tup = ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead',
          ... ('parrot', ('fresh fruit',))))))))
          >>> pp = pprint.PrettyPrinter(depth=6)
          >>> pp.pprint(tup)
          ('spam', ('eggs', ('lumberjack', ('knights', ('ni', ('dead', (...)))))))

     Changed in version 3.4: Added the 'compact' parameter.

     Changed in version 3.8: Added the 'sort_dicts' parameter.

     Changed in version 3.10: Added the 'underscore_numbers' parameter.

     Changed in version 3.11: No longer attempts to write to
     ‘sys.stdout’ if it is ‘None’.

*note PrettyPrinter: fb8. instances have the following methods:

 -- Method: PrettyPrinter.pformat (object)

     Return the formatted representation of 'object'.  This takes into
     account the options passed to the *note PrettyPrinter: fb8.
     constructor.

 -- Method: PrettyPrinter.pprint (object)

     Print the formatted representation of 'object' on the configured
     stream, followed by a newline.

The following methods provide the implementations for the corresponding
functions of the same names.  Using these methods on an instance is
slightly more efficient since new *note PrettyPrinter: fb8. objects
don’t need to be created.

 -- Method: PrettyPrinter.isreadable (object)

     Determine if the formatted representation of the object is
     “readable,” or can be used to reconstruct the value using *note
     eval(): 180.  Note that this returns ‘False’ for recursive objects.
     If the 'depth' parameter of the *note PrettyPrinter: fb8. is set
     and the object is deeper than allowed, this returns ‘False’.

 -- Method: PrettyPrinter.isrecursive (object)

     Determine if the object requires a recursive representation.

This method is provided as a hook to allow subclasses to modify the way
objects are converted to strings.  The default implementation uses the
internals of the *note saferepr(): 274e. implementation.

 -- Method: PrettyPrinter.format (object, context, maxlevels, level)

     Returns three values: the formatted version of 'object' as a
     string, a flag indicating whether the result is readable, and a
     flag indicating whether recursion was detected.  The first argument
     is the object to be presented.  The second is a dictionary which
     contains the *note id(): 1471. of objects that are part of the
     current presentation context (direct and indirect containers for
     'object' that are affecting the presentation) as the keys; if an
     object needs to be presented which is already represented in
     'context', the third return value should be ‘True’.  Recursive
     calls to the ‘format()’ method should add additional entries for
     containers to this dictionary.  The third argument, 'maxlevels',
     gives the requested limit to recursion; this will be ‘0’ if there
     is no requested limit.  This argument should be passed unmodified
     to recursive calls.  The fourth argument, 'level', gives the
     current level; recursive calls should be passed a value less than
     that of the current call.


File: python.info,  Node: Example<3>,  Prev: PrettyPrinter Objects,  Up: pprint — Data pretty printer

5.8.12.3 Example
................

To demonstrate several uses of the *note pp(): a30. function and its
parameters, let’s fetch information about a project from PyPI(1):

     >>> import json
     >>> import pprint
     >>> from urllib.request import urlopen
     >>> with urlopen('https://pypi.org/pypi/sampleproject/1.2.0/json') as resp:
     ...     project_info = json.load(resp)['info']

In its basic form, *note pp(): a30. shows the whole object:

     >>> pprint.pp(project_info)
     {'author': 'The Python Packaging Authority',
      'author_email': 'pypa-dev@googlegroups.com',
      'bugtrack_url': None,
      'classifiers': ['Development Status :: 3 - Alpha',
                      'Intended Audience :: Developers',
                      'License :: OSI Approved :: MIT License',
                      'Programming Language :: Python :: 2',
                      'Programming Language :: Python :: 2.6',
                      'Programming Language :: Python :: 2.7',
                      'Programming Language :: Python :: 3',
                      'Programming Language :: Python :: 3.2',
                      'Programming Language :: Python :: 3.3',
                      'Programming Language :: Python :: 3.4',
                      'Topic :: Software Development :: Build Tools'],
      'description': 'A sample Python project\n'
                     '=======================\n'
                     '\n'
                     'This is the description file for the project.\n'
                     '\n'
                     'The file should use UTF-8 encoding and be written using '
                     'ReStructured Text. It\n'
                     'will be used to generate the project webpage on PyPI, and '
                     'should be written for\n'
                     'that purpose.\n'
                     '\n'
                     'Typical contents for this file would include an overview of '
                     'the project, basic\n'
                     'usage examples, etc. Generally, including the project '
                     'changelog in here is not\n'
                     'a good idea, although a simple "What\'s New" section for the '
                     'most recent version\n'
                     'may be appropriate.',
      'description_content_type': None,
      'docs_url': None,
      'download_url': 'UNKNOWN',
      'downloads': {'last_day': -1, 'last_month': -1, 'last_week': -1},
      'home_page': 'https://github.com/pypa/sampleproject',
      'keywords': 'sample setuptools development',
      'license': 'MIT',
      'maintainer': None,
      'maintainer_email': None,
      'name': 'sampleproject',
      'package_url': 'https://pypi.org/project/sampleproject/',
      'platform': 'UNKNOWN',
      'project_url': 'https://pypi.org/project/sampleproject/',
      'project_urls': {'Download': 'UNKNOWN',
                       'Homepage': 'https://github.com/pypa/sampleproject'},
      'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
      'requires_dist': None,
      'requires_python': None,
      'summary': 'A sample Python project',
      'version': '1.2.0'}

The result can be limited to a certain 'depth' (ellipsis is used for
deeper contents):

     >>> pprint.pp(project_info, depth=1)
     {'author': 'The Python Packaging Authority',
      'author_email': 'pypa-dev@googlegroups.com',
      'bugtrack_url': None,
      'classifiers': [...],
      'description': 'A sample Python project\n'
                     '=======================\n'
                     '\n'
                     'This is the description file for the project.\n'
                     '\n'
                     'The file should use UTF-8 encoding and be written using '
                     'ReStructured Text. It\n'
                     'will be used to generate the project webpage on PyPI, and '
                     'should be written for\n'
                     'that purpose.\n'
                     '\n'
                     'Typical contents for this file would include an overview of '
                     'the project, basic\n'
                     'usage examples, etc. Generally, including the project '
                     'changelog in here is not\n'
                     'a good idea, although a simple "What\'s New" section for the '
                     'most recent version\n'
                     'may be appropriate.',
      'description_content_type': None,
      'docs_url': None,
      'download_url': 'UNKNOWN',
      'downloads': {...},
      'home_page': 'https://github.com/pypa/sampleproject',
      'keywords': 'sample setuptools development',
      'license': 'MIT',
      'maintainer': None,
      'maintainer_email': None,
      'name': 'sampleproject',
      'package_url': 'https://pypi.org/project/sampleproject/',
      'platform': 'UNKNOWN',
      'project_url': 'https://pypi.org/project/sampleproject/',
      'project_urls': {...},
      'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
      'requires_dist': None,
      'requires_python': None,
      'summary': 'A sample Python project',
      'version': '1.2.0'}

Additionally, maximum character 'width' can be suggested.  If a long
object cannot be split, the specified width will be exceeded:

     >>> pprint.pp(project_info, depth=1, width=60)
     {'author': 'The Python Packaging Authority',
      'author_email': 'pypa-dev@googlegroups.com',
      'bugtrack_url': None,
      'classifiers': [...],
      'description': 'A sample Python project\n'
                     '=======================\n'
                     '\n'
                     'This is the description file for the '
                     'project.\n'
                     '\n'
                     'The file should use UTF-8 encoding and be '
                     'written using ReStructured Text. It\n'
                     'will be used to generate the project '
                     'webpage on PyPI, and should be written '
                     'for\n'
                     'that purpose.\n'
                     '\n'
                     'Typical contents for this file would '
                     'include an overview of the project, '
                     'basic\n'
                     'usage examples, etc. Generally, including '
                     'the project changelog in here is not\n'
                     'a good idea, although a simple "What\'s '
                     'New" section for the most recent version\n'
                     'may be appropriate.',
      'description_content_type': None,
      'docs_url': None,
      'download_url': 'UNKNOWN',
      'downloads': {...},
      'home_page': 'https://github.com/pypa/sampleproject',
      'keywords': 'sample setuptools development',
      'license': 'MIT',
      'maintainer': None,
      'maintainer_email': None,
      'name': 'sampleproject',
      'package_url': 'https://pypi.org/project/sampleproject/',
      'platform': 'UNKNOWN',
      'project_url': 'https://pypi.org/project/sampleproject/',
      'project_urls': {...},
      'release_url': 'https://pypi.org/project/sampleproject/1.2.0/',
      'requires_dist': None,
      'requires_python': None,
      'summary': 'A sample Python project',
      'version': '1.2.0'}

   ---------- Footnotes ----------

   (1) https://pypi.org


File: python.info,  Node: reprlib — Alternate repr implementation,  Next: enum — Support for enumerations,  Prev: pprint — Data pretty printer,  Up: Data Types

5.8.13 ‘reprlib’ — Alternate ‘repr()’ implementation
----------------------------------------------------

'Source code:' Lib/reprlib.py(1)

__________________________________________________________________

The ‘reprlib’ module provides a means for producing object
representations with limits on the size of the resulting strings.  This
is used in the Python debugger and may be useful in other contexts as
well.

This module provides a class, an instance, and a function:

 -- Class: reprlib.Repr (*, maxlevel=6, maxtuple=6, maxlist=6,
          maxarray=5, maxdict=4, maxset=6, maxfrozenset=6, maxdeque=6,
          maxstring=30, maxlong=40, maxother=30, fillvalue='...',
          indent=None)

     Class which provides formatting services useful in implementing
     functions similar to the built-in *note repr(): 803.; size limits
     for different object types are added to avoid the generation of
     representations which are excessively long.

     The keyword arguments of the constructor can be used as a shortcut
     to set the attributes of the ‘Repr’ instance.  Which means that the
     following initialization:

          aRepr = reprlib.Repr(maxlevel=3)

     Is equivalent to:

          aRepr = reprlib.Repr()
          aRepr.maxlevel = 3

     See section *note Repr Objects: 275b. for more information about
     ‘Repr’ attributes.

     Changed in version 3.12: Allow attributes to be set via keyword
     arguments.

 -- Data: reprlib.aRepr

     This is an instance of *note Repr: 275a. which is used to provide
     the *note repr(): 275d. function described below.  Changing the
     attributes of this object will affect the size limits used by
     ‘repr()’ and the Python debugger.

 -- Function: reprlib.repr (obj)

     This is the *note repr(): 275e. method of ‘aRepr’.  It returns a
     string similar to that returned by the built-in function of the
     same name, but with limits on most sizes.

In addition to size-limiting tools, the module also provides a decorator
for detecting recursive calls to *note __repr__(): 61f. and substituting
a placeholder string instead.

 -- Function: @reprlib.recursive_repr (fillvalue='...')

     Decorator for *note __repr__(): 61f. methods to detect recursive
     calls within the same thread.  If a recursive call is made, the
     'fillvalue' is returned, otherwise, the usual ‘__repr__()’ call is
     made.  For example:

          >>> from reprlib import recursive_repr
          >>> class MyList(list):
          ...     @recursive_repr()
          ...     def __repr__(self):
          ...         return '<' + '|'.join(map(repr, self)) + '>'
          ...
          >>> m = MyList('abc')
          >>> m.append(m)
          >>> m.append('x')
          >>> print(m)
          <'a'|'b'|'c'|...|'x'>

     Added in version 3.2.

* Menu:

* Repr Objects::
* Subclassing Repr Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/reprlib.py


File: python.info,  Node: Repr Objects,  Next: Subclassing Repr Objects,  Up: reprlib — Alternate repr implementation

5.8.13.1 Repr Objects
.....................

*note Repr: 275a. instances provide several attributes which can be used
to provide size limits for the representations of different object
types, and methods which format specific object types.

 -- Attribute: Repr.fillvalue

     This string is displayed for recursive references.  It defaults to
     ‘...’.

     Added in version 3.11.

 -- Attribute: Repr.maxlevel

     Depth limit on the creation of recursive representations.  The
     default is ‘6’.

 -- Attribute: Repr.maxdict
 -- Attribute: Repr.maxlist
 -- Attribute: Repr.maxtuple
 -- Attribute: Repr.maxset
 -- Attribute: Repr.maxfrozenset
 -- Attribute: Repr.maxdeque
 -- Attribute: Repr.maxarray

     Limits on the number of entries represented for the named object
     type.  The default is ‘4’ for *note maxdict: 2762, ‘5’ for *note
     maxarray: 2768, and ‘6’ for the others.

 -- Attribute: Repr.maxlong

     Maximum number of characters in the representation for an integer.
     Digits are dropped from the middle.  The default is ‘40’.

 -- Attribute: Repr.maxstring

     Limit on the number of characters in the representation of the
     string.  Note that the “normal” representation of the string is
     used as the character source: if escape sequences are needed in the
     representation, these may be mangled when the representation is
     shortened.  The default is ‘30’.

 -- Attribute: Repr.maxother

     This limit is used to control the size of object types for which no
     specific formatting method is available on the *note Repr: 275a.
     object.  It is applied in a similar manner as *note maxstring:
     276a.  The default is ‘20’.

 -- Attribute: Repr.indent

     If this attribute is set to ‘None’ (the default), the output is
     formatted with no line breaks or indentation, like the standard
     *note repr(): 803.  For example:

          >>> example = [
          ...     1, 'spam', {'a': 2, 'b': 'spam eggs', 'c': {3: 4.5, 6: []}}, 'ham']
          >>> import reprlib
          >>> aRepr = reprlib.Repr()
          >>> print(aRepr.repr(example))
          [1, 'spam', {'a': 2, 'b': 'spam eggs', 'c': {3: 4.5, 6: []}}, 'ham']

     If ‘indent’ is set to a string, each recursion level is placed on
     its own line, indented by that string:

          >>> aRepr.indent = '-->'
          >>> print(aRepr.repr(example))
          [
          -->1,
          -->'spam',
          -->{
          -->-->'a': 2,
          -->-->'b': 'spam eggs',
          -->-->'c': {
          -->-->-->3: 4.5,
          -->-->-->6: [],
          -->-->},
          -->},
          -->'ham',
          ]

     Setting ‘indent’ to a positive integer value behaves as if it was
     set to a string with that number of spaces:

          >>> aRepr.indent = 4
          >>> print(aRepr.repr(example))
          [
              1,
              'spam',
              {
                  'a': 2,
                  'b': 'spam eggs',
                  'c': {
                      3: 4.5,
                      6: [],
                  },
              },
              'ham',
          ]

     Added in version 3.12.

 -- Method: Repr.repr (obj)

     The equivalent to the built-in *note repr(): 803. that uses the
     formatting imposed by the instance.

 -- Method: Repr.repr1 (obj, level)

     Recursive implementation used by *note repr(): 275e.  This uses the
     type of 'obj' to determine which formatting method to call, passing
     it 'obj' and 'level'.  The type-specific methods should call
     ‘repr1()’ to perform recursive formatting, with ‘level - 1’ for the
     value of 'level' in the recursive call.

 -- Method: Repr.repr_TYPE (obj, level)

     Formatting methods for specific types are implemented as methods
     with a name based on the type name.  In the method name, 'TYPE' is
     replaced by ‘'_'.join(type(obj).__name__.split())’.  Dispatch to
     these methods is handled by *note repr1(): 276d.  Type-specific
     methods which need to recursively format a value should call
     ‘self.repr1(subobj, level - 1)’.


File: python.info,  Node: Subclassing Repr Objects,  Prev: Repr Objects,  Up: reprlib — Alternate repr implementation

5.8.13.2 Subclassing Repr Objects
.................................

The use of dynamic dispatching by *note Repr.repr1(): 276d. allows
subclasses of *note Repr: 275a. to add support for additional built-in
object types or to modify the handling of types already supported.  This
example shows how special support for file objects could be added:

     import reprlib
     import sys

     class MyRepr(reprlib.Repr):

         def repr_TextIOWrapper(self, obj, level):
             if obj.name in {'<stdin>', '<stdout>', '<stderr>'}:
                 return obj.name
             return repr(obj)

     aRepr = MyRepr()
     print(aRepr.repr(sys.stdin))         # prints '<stdin>'

     <stdin>


File: python.info,  Node: enum — Support for enumerations,  Next: graphlib — Functionality to operate with graph-like structures,  Prev: reprlib — Alternate repr implementation,  Up: Data Types

5.8.14 ‘enum’ — Support for enumerations
----------------------------------------

Added in version 3.4.

'Source code:' Lib/enum.py(1)

Important
.........

This page contains the API reference information.  For tutorial
information and discussion of more advanced topics, see

   * *note Basic Tutorial: 2773.

   * *note Advanced Tutorial: 2774.

   * *note Enum Cookbook: 2775.

__________________________________________________________________

An enumeration:

   * is a set of symbolic names (members) bound to unique values

   * can be iterated over to return its canonical (i.e.  non-alias)
     members in definition order

   * uses 'call' syntax to return members by value

   * uses 'index' syntax to return members by name

Enumerations are created either by using *note class: 131f. syntax, or
by using function-call syntax:

     >>> from enum import Enum

     >>> # class syntax
     >>> class Color(Enum):
     ...     RED = 1
     ...     GREEN = 2
     ...     BLUE = 3

     >>> # functional syntax
     >>> Color = Enum('Color', [('RED', 1), ('GREEN', 2), ('BLUE', 3)])

Even though we can use *note class: 131f. syntax to create Enums, Enums
are not normal Python classes.  See *note How are Enums different?:
2776. for more details.

     Note: Nomenclature

        - The class ‘Color’ is an 'enumeration' (or 'enum')

        - The attributes ‘Color.RED’, ‘Color.GREEN’, etc., are
          'enumeration members' (or 'members') and are functionally
          constants.

        - The enum members have 'names' and 'values' (the name of
          ‘Color.RED’ is ‘RED’, the value of ‘Color.BLUE’ is ‘3’, etc.)

__________________________________________________________________

* Menu:

* Module contents::
* Data types::
* Utilities and decorators::
* Notes::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/enum.py


File: python.info,  Node: Module contents,  Next: Data types,  Up: enum — Support for enumerations

5.8.14.1 Module contents
........................

     *note EnumType: 1e5.

          The ‘type’ for Enum and its subclasses.

     *note Enum: 633.

          Base class for creating enumerated constants.

     *note IntEnum: d06.

          Base class for creating enumerated constants that are also
          subclasses of *note int: 257.  (*note Notes: 2778.)

     *note StrEnum: 61d.

          Base class for creating enumerated constants that are also
          subclasses of *note str: 44f.  (*note Notes: 2778.)

     *note Flag: 626.

          Base class for creating enumerated constants that can be
          combined using the bitwise operations without losing their
          *note Flag: 626. membership.

     *note IntFlag: cc1.

          Base class for creating enumerated constants that can be
          combined using the bitwise operators without losing their
          *note IntFlag: cc1. membership.  ‘IntFlag’ members are also
          subclasses of *note int: 257.  (*note Notes: 2778.)

     *note ReprEnum: 61e.

          Used by *note IntEnum: d06, *note StrEnum: 61d, and *note
          IntFlag: cc1. to keep the *note str(): 44f. of the mixed-in
          type.

     *note EnumCheck: 629.

          An enumeration with the values ‘CONTINUOUS’, ‘NAMED_FLAGS’,
          and ‘UNIQUE’, for use with *note verify(): 628. to ensure
          various constraints are met by a given enumeration.

     *note FlagBoundary: 627.

          An enumeration with the values ‘STRICT’, ‘CONFORM’, ‘EJECT’,
          and ‘KEEP’ which allows for more fine-grained control over how
          invalid values are dealt with in an enumeration.

     *note EnumDict: 1e4.

          A subclass of *note dict: 256. for use when subclassing *note
          EnumType: 1e5.

     *note auto: cc2.

          Instances are replaced with an appropriate value for Enum
          members.  *note StrEnum: 61d. defaults to the lower-cased
          version of the member name, while other Enums default to 1 and
          increase from there.

     *note property(): 62c.

          Allows *note Enum: 633. members to have attributes without
          conflicting with member names.  The ‘value’ and ‘name’
          attributes are implemented this way.

     *note unique(): 2779.

          Enum class decorator that ensures only one name is bound to
          any one value.

     *note verify(): 628.

          Enum class decorator that checks user-selectable constraints
          on an enumeration.

     *note member(): 62a.

          Make ‘obj’ a member.  Can be used as a decorator.

     *note nonmember(): 62b.

          Do not make ‘obj’ a member.  Can be used as a decorator.

     *note global_enum(): 62e.

          Modify the *note str(): 44f. and *note repr(): 803. of an enum
          to show its members as belonging to the module instead of its
          class, and export the enum members to the global namespace.

     *note show_flag_values(): 277a.

          Return a list of all power-of-two integers contained in a
          flag.

     *note enum.bin(): 15d8.

          Like built-in *note bin(): 12f0, except negative values are
          represented in two’s complement, and the leading bit always
          indicates sign (‘0’ implies positive, ‘1’ implies negative).

Added in version 3.6: ‘Flag’, ‘IntFlag’, ‘auto’

Added in version 3.11: ‘StrEnum’, ‘EnumCheck’, ‘ReprEnum’,
‘FlagBoundary’, ‘property’, ‘member’, ‘nonmember’, ‘global_enum’,
‘show_flag_values’

Added in version 3.13: ‘EnumDict’

__________________________________________________________________


File: python.info,  Node: Data types,  Next: Utilities and decorators,  Prev: Module contents,  Up: enum — Support for enumerations

5.8.14.2 Data types
...................

 -- Class: enum.EnumType

     'EnumType' is the *note metaclass: 2136. for 'enum' enumerations.
     It is possible to subclass 'EnumType' – see *note Subclassing
     EnumType: 277c. for details.

     ‘EnumType’ is responsible for setting the correct ‘__repr__()’,
     ‘__str__()’, ‘__format__()’, and ‘__reduce__()’ methods on the
     final 'enum', as well as creating the enum members, properly
     handling duplicates, providing iteration over the enum class, etc.

     Added in version 3.11: Before 3.11 ‘EnumType’ was called
     ‘EnumMeta’, which is still available as an alias.

      -- Method: __call__ (cls, value, names=None, *, module=None,
               qualname=None, type=None, start=1, boundary=None)

          This method is called in two different ways:

             * to look up an existing member:


                    cls: The enum class being called.


                    value: The value to lookup.

             * to use the ‘cls’ enum to create a new enum (only if the
               existing enum does not have any members):


                    cls: The enum class being called.


                    value: The name of the new Enum to create.


                    names: The names/values of the members for the new
                    Enum.


                    module: The name of the module the new Enum is
                    created in.


                    qualname: The actual location in the module where
                    this Enum can be found.


                    type: A mix-in type for the new Enum.


                    start: The first integer value for the Enum (used by
                    *note auto: cc2.).


                    boundary: How to handle out-of-range values from bit
                    operations (*note Flag: 626. only).

      -- Method: __contains__ (cls, member)

          Returns ‘True’ if member belongs to the ‘cls’:

               >>> some_var = Color.RED
               >>> some_var in Color
               True
               >>> Color.RED.value in Color
               True

          Changed in version 3.12: Before Python 3.12, a ‘TypeError’ is
          raised if a non-Enum-member is used in a containment check.

      -- Method: __dir__ (cls)

          Returns ‘['__class__', '__doc__', '__members__',
          '__module__']’ and the names of the members in 'cls':

               >>> dir(Color)
               ['BLUE', 'GREEN', 'RED', '__class__', '__contains__', '__doc__', '__getitem__', '__init_subclass__', '__iter__', '__len__', '__members__', '__module__', '__name__', '__qualname__']

      -- Method: __getitem__ (cls, name)

          Returns the Enum member in 'cls' matching 'name', or raises a
          *note KeyError: 345.:

               >>> Color['BLUE']
               <Color.BLUE: 3>

      -- Method: __iter__ (cls)

          Returns each member in 'cls' in definition order:

               >>> list(Color)
               [<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 3>]

      -- Method: __len__ (cls)

          Returns the number of member in 'cls':

               >>> len(Color)
               3

      -- Attribute: __members__

          Returns a mapping of every enum name to its member, including
          aliases

      -- Method: __reversed__ (cls)

          Returns each member in 'cls' in reverse definition order:

               >>> list(reversed(Color))
               [<Color.BLUE: 3>, <Color.GREEN: 2>, <Color.RED: 1>]

 -- Class: enum.Enum

     'Enum' is the base class for all 'enum' enumerations.

      -- Attribute: name

          The name used to define the ‘Enum’ member:

               >>> Color.BLUE.name
               'BLUE'

      -- Attribute: value

          The value given to the ‘Enum’ member:

               >>> Color.RED.value
               1

          Value of the member, can be set in *note __new__(): 2787.

               Note: Enum member values

               Member values can be anything: *note int: 257, *note str:
               44f, etc.  If the exact value is unimportant you may use
               *note auto: cc2. instances and an appropriate value will
               be chosen for you.  See ‘auto’ for the details.

               While mutable/unhashable values, such as *note dict: 256,
               *note list: 614. or a mutable *note dataclass: 1cb, can
               be used, they will have a quadratic performance impact
               during creation relative to the total number of
               mutable/unhashable values in the enum.

      -- Attribute: _name_

          Name of the member.

      -- Attribute: _value_

          Value of the member, can be set in *note __new__(): 2787.

      -- Attribute: _order_

          No longer used, kept for backward compatibility.  (class
          attribute, removed during class creation).

          The ‘_order_’ attribute can be provided to help keep Python 2
          / Python 3 code in sync.  It will be checked against the
          actual order of the enumeration and raise an error if the two
          do not match:

               >>> class Color(Enum):
               ...     _order_ = 'RED GREEN BLUE'
               ...     RED = 1
               ...     BLUE = 3
               ...     GREEN = 2
               ...
               Traceback (most recent call last):
               ...
               TypeError: member order does not match _order_:
                  ['RED', 'BLUE', 'GREEN']
                  ['RED', 'GREEN', 'BLUE']

               Note: In Python 2 code the ‘_order_’ attribute is
               necessary as definition order is lost before it can be
               recorded.

          Added in version 3.6.

      -- Attribute: _ignore_

          ‘_ignore_’ is only used during creation and is removed from
          the enumeration once creation is complete.

          ‘_ignore_’ is a list of names that will not become members,
          and whose names will also be removed from the completed
          enumeration.  See *note TimePeriod: 278c. for an example.

          Added in version 3.7.

      -- Method: __dir__ (self)

          Returns ‘['__class__', '__doc__', '__module__', 'name',
          'value']’ and any public methods defined on 'self.__class__':

               >>> from enum import Enum
               >>> import datetime as dt
               >>> class Weekday(Enum):
               ...     MONDAY = 1
               ...     TUESDAY = 2
               ...     WEDNESDAY = 3
               ...     THURSDAY = 4
               ...     FRIDAY = 5
               ...     SATURDAY = 6
               ...     SUNDAY = 7
               ...     @classmethod
               ...     def today(cls):
               ...         print(f'today is {cls(dt.date.today().isoweekday()).name}')
               ...
               >>> dir(Weekday.SATURDAY)
               ['__class__', '__doc__', '__eq__', '__hash__', '__module__', 'name', 'today', 'value']

      -- Method: _generate_next_value_ (name, start, count, last_values)


               name: The name of the member being defined (e.g.  ‘RED’).


               start: The start value for the Enum; the default is 1.


               count: The number of members currently defined, not
               including this one.


               last_values: A list of the previous values.

          A 'staticmethod' that is used to determine the next value
          returned by *note auto: cc2.

               Note: For standard ‘Enum’ classes the next value chosen
               is the highest value seen incremented by one.

               For *note Flag: 626. classes the next value chosen will
               be the next highest power-of-two.

          This method may be overridden, e.g.:

               >>> from enum import auto, Enum
               >>> class PowersOfThree(Enum):
               ...     @staticmethod
               ...     def _generate_next_value_(name, start, count, last_values):
               ...         return 3 ** (count + 1)
               ...     FIRST = auto()
               ...     SECOND = auto()
               ...
               >>> PowersOfThree.SECOND.value
               9

          Added in version 3.6.

          Changed in version 3.13: Prior versions would use the last
          seen value instead of the highest value.

      -- Method: __init__ (self, *args, **kwds)

          By default, does nothing.  If multiple values are given in the
          member assignment, those values become separate arguments to
          ‘__init__’; e.g.

               >>> from enum import Enum
               >>> class Weekday(Enum):
               ...     MONDAY = 1, 'Mon'

          ‘Weekday.__init__()’ would be called as
          ‘Weekday.__init__(self, 1, 'Mon')’

      -- Method: __init_subclass__ (cls, **kwds)

          A 'classmethod' that is used to further configure subsequent
          subclasses.  By default, does nothing.

      -- Method: _missing_ (cls, value)

          A 'classmethod' for looking up values not found in 'cls'.  By
          default it does nothing, but can be overridden to implement
          custom search behavior:

               >>> from enum import auto, StrEnum
               >>> class Build(StrEnum):
               ...     DEBUG = auto()
               ...     OPTIMIZED = auto()
               ...     @classmethod
               ...     def _missing_(cls, value):
               ...         value = value.lower()
               ...         for member in cls:
               ...             if member.value == value:
               ...                 return member
               ...         return None
               ...
               >>> Build.DEBUG.value
               'debug'
               >>> Build('deBUG')
               <Build.DEBUG: 'debug'>

          Added in version 3.6.

      -- Method: __new__ (cls, *args, **kwds)

          By default, doesn’t exist.  If specified, either in the enum
          class definition or in a mixin class (such as ‘int’), all
          values given in the member assignment will be passed; e.g.

               >>> from enum import Enum
               >>> class MyIntEnum(int, Enum):
               ...     TWENTYSIX = '1a', 16

          results in the call ‘int('1a', 16)’ and a value of ‘26’ for
          the member.

               Note: When writing a custom ‘__new__’, do not use
               ‘super().__new__’ – call the appropriate ‘__new__’
               instead.

      -- Method: __repr__ (self)

          Returns the string used for 'repr()' calls.  By default,
          returns the 'Enum' name, member name, and value, but can be
          overridden:

               >>> from enum import auto, Enum
               >>> class OtherStyle(Enum):
               ...     ALTERNATE = auto()
               ...     OTHER = auto()
               ...     SOMETHING_ELSE = auto()
               ...     def __repr__(self):
               ...         cls_name = self.__class__.__name__
               ...         return f'{cls_name}.{self.name}'
               ...
               >>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
               (OtherStyle.ALTERNATE, 'OtherStyle.ALTERNATE', 'OtherStyle.ALTERNATE')

      -- Method: __str__ (self)

          Returns the string used for 'str()' calls.  By default,
          returns the 'Enum' name and member name, but can be
          overridden:

               >>> from enum import auto, Enum
               >>> class OtherStyle(Enum):
               ...     ALTERNATE = auto()
               ...     OTHER = auto()
               ...     SOMETHING_ELSE = auto()
               ...     def __str__(self):
               ...         return f'{self.name}'
               ...
               >>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
               (<OtherStyle.ALTERNATE: 1>, 'ALTERNATE', 'ALTERNATE')

      -- Method: __format__ (self)

          Returns the string used for 'format()' and 'f-string' calls.
          By default, returns *note __str__(): 625. return value, but
          can be overridden:

               >>> from enum import auto, Enum
               >>> class OtherStyle(Enum):
               ...     ALTERNATE = auto()
               ...     OTHER = auto()
               ...     SOMETHING_ELSE = auto()
               ...     def __format__(self, spec):
               ...         return f'{self.name}'
               ...
               >>> OtherStyle.ALTERNATE, str(OtherStyle.ALTERNATE), f"{OtherStyle.ALTERNATE}"
               (<OtherStyle.ALTERNATE: 1>, 'OtherStyle.ALTERNATE', 'ALTERNATE')

          Note: Using *note auto: cc2. with ‘Enum’ results in integers
          of increasing value, starting with ‘1’.

     Changed in version 3.12: Added *note Dataclass support: 189c.

      -- Method: _add_alias_ ()

          Adds a new name as an alias to an existing member:

               >>> Color.RED._add_alias_("ERROR")
               >>> Color.ERROR
               <Color.RED: 1>

          Raises a *note NameError: 442. if the name is already assigned
          to a different member.

          Added in version 3.13.

      -- Method: _add_value_alias_ ()

          Adds a new value as an alias to an existing member:

               >>> Color.RED._add_value_alias_(42)
               >>> Color(42)
               <Color.RED: 1>

               Raises a *note ValueError: 202. if the value is already linked with a different member.
               See *note MultiValueEnum: 2793. for an example.

          Added in version 3.13.

 -- Class: enum.IntEnum

     'IntEnum' is the same as *note Enum: 633, but its members are also
     integers and can be used anywhere that an integer can be used.  If
     any integer operation is performed with an 'IntEnum' member, the
     resulting value loses its enumeration status.

          >>> from enum import IntEnum
          >>> class Number(IntEnum):
          ...     ONE = 1
          ...     TWO = 2
          ...     THREE = 3
          ...
          >>> Number.THREE
          <Number.THREE: 3>
          >>> Number.ONE + Number.TWO
          3
          >>> Number.THREE + 5
          8
          >>> Number.THREE == 3
          True

          Note: Using *note auto: cc2. with ‘IntEnum’ results in
          integers of increasing value, starting with ‘1’.

     Changed in version 3.11: *note __str__(): 620. is now
     ‘int.__str__()’ to better support the 'replacement of existing
     constants' use-case.  *note __format__(): 621. was already
     ‘int.__format__()’ for that same reason.

 -- Class: enum.StrEnum

     'StrEnum' is the same as *note Enum: 633, but its members are also
     strings and can be used in most of the same places that a string
     can be used.  The result of any string operation performed on or
     with a 'StrEnum' member is not part of the enumeration.

          >>> from enum import StrEnum, auto
          >>> class Color(StrEnum):
          ...     RED = 'r'
          ...     GREEN = 'g'
          ...     BLUE = 'b'
          ...     UNKNOWN = auto()
          ...
          >>> Color.RED
          <Color.RED: 'r'>
          >>> Color.UNKNOWN
          <Color.UNKNOWN: 'unknown'>
          >>> str(Color.UNKNOWN)
          'unknown'

          Note: There are places in the stdlib that check for an exact
          *note str: 44f. instead of a ‘str’ subclass (i.e.
          ‘type(unknown) == str’ instead of ‘isinstance(unknown, str)’),
          and in those locations you will need to use
          ‘str(MyStrEnum.MY_MEMBER)’.

          Note: Using *note auto: cc2. with ‘StrEnum’ results in the
          lower-cased member name as the value.

          Note: *note __str__(): 620. is ‘str.__str__()’ to better
          support the 'replacement of existing constants' use-case.
          *note __format__(): 621. is likewise ‘str.__format__()’ for
          that same reason.

     Added in version 3.11.

 -- Class: enum.Flag

     ‘Flag’ is the same as *note Enum: 633, but its members support the
     bitwise operators ‘&’ ('AND'), ‘|’ ('OR'), ‘^’ ('XOR'), and ‘~’
     ('INVERT'); the results of those operations are (aliases of)
     members of the enumeration.

      -- Method: __contains__ (self, value)

          Returns 'True' if value is in self:

               >>> from enum import Flag, auto
               >>> class Color(Flag):
               ...     RED = auto()
               ...     GREEN = auto()
               ...     BLUE = auto()
               ...
               >>> purple = Color.RED | Color.BLUE
               >>> white = Color.RED | Color.GREEN | Color.BLUE
               >>> Color.GREEN in purple
               False
               >>> Color.GREEN in white
               True
               >>> purple in white
               True
               >>> white in purple
               False

      -- Method: __iter__(self):

          Returns all contained non-alias members:

               >>> list(Color.RED)
               [<Color.RED: 1>]
               >>> list(purple)
               [<Color.RED: 1>, <Color.BLUE: 4>]

          Added in version 3.11.

      -- Method: __len__(self):

          Returns number of members in flag:

               >>> len(Color.GREEN)
               1
               >>> len(white)
               3

          Added in version 3.11.

      -- Method: __bool__(self):

          Returns 'True' if any members in flag, 'False' otherwise:

               >>> bool(Color.GREEN)
               True
               >>> bool(white)
               True
               >>> black = Color(0)
               >>> bool(black)
               False

      -- Method: __or__ (self, other)

          Returns current flag binary or’ed with other:

               >>> Color.RED | Color.GREEN
               <Color.RED|GREEN: 3>

      -- Method: __and__ (self, other)

          Returns current flag binary and’ed with other:

               >>> purple & white
               <Color.RED|BLUE: 5>
               >>> purple & Color.GREEN
               <Color: 0>

      -- Method: __xor__ (self, other)

          Returns current flag binary xor’ed with other:

               >>> purple ^ white
               <Color.GREEN: 2>
               >>> purple ^ Color.GREEN
               <Color.RED|GREEN|BLUE: 7>

      -- Method: __invert__(self):

          Returns all the flags in 'type(self)' that are not in 'self':

               >>> ~white
               <Color: 0>
               >>> ~purple
               <Color.GREEN: 2>
               >>> ~Color.RED
               <Color.GREEN|BLUE: 6>

      -- Method: _numeric_repr_ ()

          Function used to format any remaining unnamed numeric values.
          Default is the value’s repr; common choices are *note hex():
          1317. and *note oct(): 1316.

          Note: Using *note auto: cc2. with ‘Flag’ results in integers
          that are powers of two, starting with ‘1’.

     Changed in version 3.11: The 'repr()' of zero-valued flags has
     changed.  It is now::

          >>> Color(0)
          <Color: 0>

 -- Class: enum.IntFlag

     ‘IntFlag’ is the same as *note Flag: 626, but its members are also
     integers and can be used anywhere that an integer can be used.

          >>> from enum import IntFlag, auto
          >>> class Color(IntFlag):
          ...     RED = auto()
          ...     GREEN = auto()
          ...     BLUE = auto()
          ...
          >>> Color.RED & 2
          <Color: 0>
          >>> Color.RED | 2
          <Color.RED|GREEN: 3>

     If any integer operation is performed with an 'IntFlag' member, the
     result is not an 'IntFlag':

          >>> Color.RED + 2
          3

     If a *note Flag: 626. operation is performed with an 'IntFlag'
     member and:

        * the result is a valid 'IntFlag': an 'IntFlag' is returned

        * the result is not a valid 'IntFlag': the result depends on the
          *note FlagBoundary: 627. setting

     The *note repr(): 803. of unnamed zero-valued flags has changed.
     It is now:

          >>> Color(0)
          <Color: 0>

          Note: Using *note auto: cc2. with ‘IntFlag’ results in
          integers that are powers of two, starting with ‘1’.

     Changed in version 3.11: *note __str__(): 620. is now
     ‘int.__str__()’ to better support the 'replacement of existing
     constants' use-case.  *note __format__(): 621. was already
     ‘int.__format__()’ for that same reason.

     Inversion of an ‘IntFlag’ now returns a positive value that is the
     union of all flags not in the given flag, rather than a negative
     value.  This matches the existing *note Flag: 626. behavior.

 -- Class: enum.ReprEnum

     ‘ReprEnum’ uses the *note repr(): 189d. of *note Enum: 633, but the
     *note str(): 44f. of the mixed-in data type:

        * ‘int.__str__()’ for *note IntEnum: d06. and *note IntFlag:
          cc1.

        * ‘str.__str__()’ for *note StrEnum: 61d.

     Inherit from ‘ReprEnum’ to keep the *note str(): 44f. / *note
     format(): 622. of the mixed-in data type instead of using the *note
     Enum: 633.-default *note str(): 625.

     Added in version 3.11.

 -- Class: enum.EnumCheck

     'EnumCheck' contains the options used by the *note verify(): 628.
     decorator to ensure various constraints; failed constraints result
     in a *note ValueError: 202.

      -- Attribute: UNIQUE

          Ensure that each value has only one name:

               >>> from enum import Enum, verify, UNIQUE
               >>> @verify(UNIQUE)
               ... class Color(Enum):
               ...     RED = 1
               ...     GREEN = 2
               ...     BLUE = 3
               ...     CRIMSON = 1
               Traceback (most recent call last):
               ...
               ValueError: aliases found in <enum 'Color'>: CRIMSON -> RED

      -- Attribute: CONTINUOUS

          Ensure that there are no missing values between the
          lowest-valued member and the highest-valued member:

               >>> from enum import Enum, verify, CONTINUOUS
               >>> @verify(CONTINUOUS)
               ... class Color(Enum):
               ...     RED = 1
               ...     GREEN = 2
               ...     BLUE = 5
               Traceback (most recent call last):
               ...
               ValueError: invalid enum 'Color': missing values 3, 4

      -- Attribute: NAMED_FLAGS

          Ensure that any flag groups/masks contain only named flags –
          useful when values are specified instead of being generated by
          *note auto(): cc2.:

               >>> from enum import Flag, verify, NAMED_FLAGS
               >>> @verify(NAMED_FLAGS)
               ... class Color(Flag):
               ...     RED = 1
               ...     GREEN = 2
               ...     BLUE = 4
               ...     WHITE = 15
               ...     NEON = 31
               Traceback (most recent call last):
               ...
               ValueError: invalid Flag 'Color': aliases WHITE and NEON are missing combined values of 0x18 [use enum.show_flag_values(value) for details]

          Note: CONTINUOUS and NAMED_FLAGS are designed to work with
          integer-valued members.

     Added in version 3.11.

 -- Class: enum.FlagBoundary

     ‘FlagBoundary’ controls how out-of-range values are handled in
     *note Flag: 626. and its subclasses.

      -- Attribute: STRICT

          Out-of-range values cause a *note ValueError: 202. to be
          raised.  This is the default for *note Flag: 626.:

               >>> from enum import Flag, STRICT, auto
               >>> class StrictFlag(Flag, boundary=STRICT):
               ...     RED = auto()
               ...     GREEN = auto()
               ...     BLUE = auto()
               ...
               >>> StrictFlag(2**2 + 2**4)
               Traceback (most recent call last):
               ...
               ValueError: <flag 'StrictFlag'> invalid value 20
                   given 0b0 10100
                 allowed 0b0 00111

      -- Attribute: CONFORM

          Out-of-range values have invalid values removed, leaving a
          valid *note Flag: 626. value:

               >>> from enum import Flag, CONFORM, auto
               >>> class ConformFlag(Flag, boundary=CONFORM):
               ...     RED = auto()
               ...     GREEN = auto()
               ...     BLUE = auto()
               ...
               >>> ConformFlag(2**2 + 2**4)
               <ConformFlag.BLUE: 4>

      -- Attribute: EJECT

          Out-of-range values lose their *note Flag: 626. membership and
          revert to *note int: 257.

               >>> from enum import Flag, EJECT, auto
               >>> class EjectFlag(Flag, boundary=EJECT):
               ...     RED = auto()
               ...     GREEN = auto()
               ...     BLUE = auto()
               ...
               >>> EjectFlag(2**2 + 2**4)
               20

      -- Attribute: KEEP

          Out-of-range values are kept, and the *note Flag: 626.
          membership is kept.  This is the default for *note IntFlag:
          cc1.:

               >>> from enum import Flag, KEEP, auto
               >>> class KeepFlag(Flag, boundary=KEEP):
               ...     RED = auto()
               ...     GREEN = auto()
               ...     BLUE = auto()
               ...
               >>> KeepFlag(2**2 + 2**4)
               <KeepFlag.BLUE|16: 20>

     Added in version 3.11.

 -- Class: enum.EnumDict

     'EnumDict' is a subclass of *note dict: 256. that is used as the
     namespace for defining enum classes (see *note Preparing the class
     namespace: c7f.).  It is exposed to allow subclasses of *note
     EnumType: 1e5. with advanced behavior like having multiple values
     per member.  It should be called with the name of the enum class
     being created, otherwise private names and internal classes will
     not be handled correctly.

     Note that only the *note MutableMapping: 10f0. interface (*note
     __setitem__(): 1313. and *note update(): 14b4.) is overridden.  It
     may be possible to bypass the checks using other ‘dict’ operations
     like *note |=: 2166.

      -- Attribute: member_names

          A list of member names.

     Added in version 3.13.

__________________________________________________________________

* Menu:

* Supported __dunder__ names::
* Supported _sunder_ names::


File: python.info,  Node: Supported __dunder__ names,  Next: Supported _sunder_ names,  Up: Data types

5.8.14.3 Supported ‘__dunder__’ names
.....................................

*note __members__: 2783. is a read-only ordered mapping of
‘member_name’:‘member’ items.  It is only available on the class.

*note __new__(): 2787, if specified, must create and return the enum
members; it is also a very good idea to set the member’s *note _value_:
2789. appropriately.  Once all the members are created it is no longer
used.


File: python.info,  Node: Supported _sunder_ names,  Prev: Supported __dunder__ names,  Up: Data types

5.8.14.4 Supported ‘_sunder_’ names
...................................

   - *note _name_: 2788. – name of the member

   - *note _value_: 2789. – value of the member; can be set in ‘__new__’

   - *note _missing_(): 2790. – a lookup function used when a value is
     not found; may be overridden

   - *note _ignore_: 278b. – a list of names, either as a *note list:
     614. or a *note str: 44f, that will not be transformed into
     members, and will be removed from the final class

   - *note _order_: 278a. – no longer used, kept for backward
     compatibility (class attribute, removed during class creation)

   - *note _generate_next_value_(): 278d. – used to get an appropriate
     value for an enum member; may be overridden

   - *note _add_alias_(): 2791. – adds a new name as an alias to an
     existing member.

   - *note _add_value_alias_(): 2792. – adds a new value as an alias to
     an existing member.

   - While ‘_sunder_’ names are generally reserved for the further
     development of the *note Enum: 633. class and can not be used, some
     are explicitly allowed:

        - ‘_repr_*’ (e.g.  ‘_repr_html_’), as used in IPython's rich
          display(1)

Added in version 3.6: ‘_missing_’, ‘_order_’, ‘_generate_next_value_’

Added in version 3.7: ‘_ignore_’

Added in version 3.13: ‘_add_alias_’, ‘_add_value_alias_’, ‘_repr_*’

__________________________________________________________________

   ---------- Footnotes ----------

   (1) 
https://ipython.readthedocs.io/en/stable/config/integrating.html#rich-display


File: python.info,  Node: Utilities and decorators,  Next: Notes,  Prev: Data types,  Up: enum — Support for enumerations

5.8.14.5 Utilities and decorators
.................................

 -- Class: enum.auto

     'auto' can be used in place of a value.  If used, the 'Enum'
     machinery will call an *note Enum: 633.’s *note
     _generate_next_value_(): 278d. to get an appropriate value.  For
     ‘Enum’ and *note IntEnum: d06. that appropriate value will be the
     last value plus one; for *note Flag: 626. and *note IntFlag: cc1.
     it will be the first power-of-two greater than the highest value;
     for *note StrEnum: 61d. it will be the lower-cased version of the
     member’s name.  Care must be taken if mixing 'auto()' with manually
     specified values.

     'auto' instances are only resolved when at the top level of an
     assignment, either by itself or as part of a tuple:

        * ‘FIRST = auto()’ will work (auto() is replaced with ‘1’);

        * ‘SECOND = auto(), -2’ will work (auto is replaced with ‘2’, so
          ‘2, -2’ is used to create the ‘SECOND’ enum member;

        * ‘THREE = [auto(), -3]’ will 'not' work (‘[<auto instance>,
          -3]’ is used to create the ‘THREE’ enum member)

     Changed in version 3.11.1: In prior versions, ‘auto()’ had to be
     the only thing on the assignment line to work properly.

     ‘_generate_next_value_’ can be overridden to customize the values
     used by 'auto'.

          Note: in 3.13 the default ‘_generate_next_value_’ will always
          return the highest member value incremented by 1, and will
          fail if any member is an incompatible type.

 -- Function: @enum.property

     A decorator similar to the built-in 'property', but specifically
     for enumerations.  It allows member attributes to have the same
     names as members themselves.

          Note: the 'property' and the member must be defined in
          separate classes; for example, the 'value' and 'name'
          attributes are defined in the 'Enum' class, and 'Enum'
          subclasses can define members with the names ‘value’ and
          ‘name’.

     Added in version 3.11.

 -- Function: @enum.unique

     A *note class: 131f. decorator specifically for enumerations.  It
     searches an enumeration’s *note __members__: 2783, gathering any
     aliases it finds; if any are found *note ValueError: 202. is raised
     with the details:

          >>> from enum import Enum, unique
          >>> @unique
          ... class Mistake(Enum):
          ...     ONE = 1
          ...     TWO = 2
          ...     THREE = 3
          ...     FOUR = 3
          ...
          Traceback (most recent call last):
          ...
          ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE

 -- Function: @enum.verify

     A *note class: 131f. decorator specifically for enumerations.
     Members from *note EnumCheck: 629. are used to specify which
     constraints should be checked on the decorated enumeration.

     Added in version 3.11.

 -- Function: @enum.member

     A decorator for use in enums: its target will become a member.

     Added in version 3.11.

 -- Function: @enum.nonmember

     A decorator for use in enums: its target will not become a member.

     Added in version 3.11.

 -- Function: @enum.global_enum

     A decorator to change the *note str(): 44f. and *note repr(): 803.
     of an enum to show its members as belonging to the module instead
     of its class.  Should only be used when the enum members are
     exported to the module global namespace (see *note re.RegexFlag:
     630. for an example).

     Added in version 3.11.

 -- Function: enum.show_flag_values (value)

     Return a list of all power-of-two integers contained in a flag
     'value'.

     Added in version 3.11.

 -- Function: enum.bin (num, max_bits=None)

     Like built-in ‘bin()’, except negative values are represented in
     two’s complement, and the leading bit always indicates sign (‘0’
     implies positive, ‘1’ implies negative).

          >>> import enum
          >>> enum.bin(10)
          '0b0 1010'
          >>> enum.bin(~10)   # ~10 is -11
          '0b1 0101'

     Added in version 3.11.

__________________________________________________________________


File: python.info,  Node: Notes,  Prev: Utilities and decorators,  Up: enum — Support for enumerations

5.8.14.6 Notes
..............

*note IntEnum: d06, *note StrEnum: 61d, and *note IntFlag: cc1.

     These three enum types are designed to be drop-in replacements for
     existing integer- and string-based values; as such, they have extra
     limitations:

        - ‘__str__’ uses the value and not the name of the enum member

        - ‘__format__’, because it uses ‘__str__’, will also use the
          value of the enum member instead of its name

     If you do not need/want those limitations, you can either create
     your own base class by mixing in the ‘int’ or ‘str’ type yourself:

          >>> from enum import Enum
          >>> class MyIntEnum(int, Enum):
          ...     pass

     or you can reassign the appropriate *note str(): 44f, etc., in your
     enum:

          >>> from enum import Enum, IntEnum
          >>> class MyIntEnum(IntEnum):
          ...     __str__ = Enum.__str__


File: python.info,  Node: graphlib — Functionality to operate with graph-like structures,  Prev: enum — Support for enumerations,  Up: Data Types

5.8.15 ‘graphlib’ — Functionality to operate with graph-like structures
-----------------------------------------------------------------------

'Source code:' Lib/graphlib.py(1)

__________________________________________________________________

 -- Class: graphlib.TopologicalSorter (graph=None)

     Provides functionality to topologically sort a graph of *note
     hashable: 613. nodes.

     A topological order is a linear ordering of the vertices in a graph
     such that for every directed edge u -> v from vertex u to vertex v,
     vertex u comes before vertex v in the ordering.  For instance, the
     vertices of the graph may represent tasks to be performed, and the
     edges may represent constraints that one task must be performed
     before another; in this example, a topological ordering is just a
     valid sequence for the tasks.  A complete topological ordering is
     possible if and only if the graph has no directed cycles, that is,
     if it is a directed acyclic graph.

     If the optional 'graph' argument is provided it must be a
     dictionary representing a directed acyclic graph where the keys are
     nodes and the values are iterables of all predecessors of that node
     in the graph (the nodes that have edges that point to the value in
     the key).  Additional nodes can be added to the graph using the
     *note add(): 27a9. method.

     In the general case, the steps required to perform the sorting of a
     given graph are as follows:

        * Create an instance of the ‘TopologicalSorter’ with an optional
          initial graph.

        * Add additional nodes to the graph.

        * Call *note prepare(): 27aa. on the graph.

        * While *note is_active(): 27ab. is ‘True’, iterate over the
          nodes returned by *note get_ready(): 27ac. and process them.
          Call *note done(): 27ad. on each node as it finishes
          processing.

     In case just an immediate sorting of the nodes in the graph is
     required and no parallelism is involved, the convenience method
     *note TopologicalSorter.static_order(): 27ae. can be used directly:

          >>> graph = {"D": {"B", "C"}, "C": {"A"}, "B": {"A"}}
          >>> ts = TopologicalSorter(graph)
          >>> tuple(ts.static_order())
          ('A', 'C', 'B', 'D')

     The class is designed to easily support parallel processing of the
     nodes as they become ready.  For instance:

          topological_sorter = TopologicalSorter()

          # Add nodes to 'topological_sorter'...

          topological_sorter.prepare()
          while topological_sorter.is_active():
              for node in topological_sorter.get_ready():
                  # Worker threads or processes take nodes to work on off the
                  # 'task_queue' queue.
                  task_queue.put(node)

              # When the work for a node is done, workers put the node in
              # 'finalized_tasks_queue' so we can get more nodes to work on.
              # The definition of 'is_active()' guarantees that, at this point, at
              # least one node has been placed on 'task_queue' that hasn't yet
              # been passed to 'done()', so this blocking 'get()' must (eventually)
              # succeed.  After calling 'done()', we loop back to call 'get_ready()'
              # again, so put newly freed nodes on 'task_queue' as soon as
              # logically possible.
              node = finalized_tasks_queue.get()
              topological_sorter.done(node)

      -- Method: add (node, *predecessors)

          Add a new node and its predecessors to the graph.  Both the
          'node' and all elements in 'predecessors' must be *note
          hashable: 613.

          If called multiple times with the same node argument, the set
          of dependencies will be the union of all dependencies passed
          in.

          It is possible to add a node with no dependencies
          ('predecessors' is not provided) or to provide a dependency
          twice.  If a node that has not been provided before is
          included among 'predecessors' it will be automatically added
          to the graph with no predecessors of its own.

          Raises *note ValueError: 202. if called after *note prepare():
          27aa.

      -- Method: prepare ()

          Mark the graph as finished and check for cycles in the graph.
          If any cycle is detected, *note CycleError: 27af. will be
          raised, but *note get_ready(): 27ac. can still be used to
          obtain as many nodes as possible until cycles block more
          progress.  After a call to this function, the graph cannot be
          modified, and therefore no more nodes can be added using *note
          add(): 27a9.

      -- Method: is_active ()

          Returns ‘True’ if more progress can be made and ‘False’
          otherwise.  Progress can be made if cycles do not block the
          resolution and either there are still nodes ready that haven’t
          yet been returned by *note TopologicalSorter.get_ready():
          27ac. or the number of nodes marked *note
          TopologicalSorter.done(): 27ad. is less than the number that
          have been returned by ‘TopologicalSorter.get_ready()’.

          The *note __bool__(): 131d. method of this class defers to
          this function, so instead of:

               if ts.is_active():
                   ...

          it is possible to simply do:

               if ts:
                   ...

          Raises *note ValueError: 202. if called without calling *note
          prepare(): 27aa. previously.

      -- Method: done (*nodes)

          Marks a set of nodes returned by *note
          TopologicalSorter.get_ready(): 27ac. as processed, unblocking
          any successor of each node in 'nodes' for being returned in
          the future by a call to ‘TopologicalSorter.get_ready()’.

          Raises *note ValueError: 202. if any node in 'nodes' has
          already been marked as processed by a previous call to this
          method or if a node was not added to the graph by using *note
          TopologicalSorter.add(): 27a9, if called without calling *note
          prepare(): 27aa. or if node has not yet been returned by *note
          get_ready(): 27ac.

      -- Method: get_ready ()

          Returns a ‘tuple’ with all the nodes that are ready.
          Initially it returns all nodes with no predecessors, and once
          those are marked as processed by calling *note
          TopologicalSorter.done(): 27ad, further calls will return all
          new nodes that have all their predecessors already processed.
          Once no more progress can be made, empty tuples are returned.

          Raises *note ValueError: 202. if called without calling *note
          prepare(): 27aa. previously.

      -- Method: static_order ()

          Returns an iterator object which will iterate over nodes in a
          topological order.  When using this method, *note prepare():
          27aa. and *note done(): 27ad. should not be called.  This
          method is equivalent to:

               def static_order(self):
                   self.prepare()
                   while self.is_active():
                       node_group = self.get_ready()
                       yield from node_group
                       self.done(*node_group)

          The particular order that is returned may depend on the
          specific order in which the items were inserted in the graph.
          For example:

               >>> ts = TopologicalSorter()
               >>> ts.add(3, 2, 1)
               >>> ts.add(1, 0)
               >>> print([*ts.static_order()])
               [2, 0, 1, 3]

               >>> ts2 = TopologicalSorter()
               >>> ts2.add(1, 0)
               >>> ts2.add(3, 2, 1)
               >>> print([*ts2.static_order()])
               [0, 2, 1, 3]

          This is due to the fact that “0” and “2” are in the same level
          in the graph (they would have been returned in the same call
          to *note get_ready(): 27ac.) and the order between them is
          determined by the order of insertion.

          If any cycle is detected, *note CycleError: 27af. will be
          raised.

     Added in version 3.9.

* Menu:

* Exceptions: Exceptions<4>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/graphlib.py


File: python.info,  Node: Exceptions<4>,  Up: graphlib — Functionality to operate with graph-like structures

5.8.15.1 Exceptions
...................

The ‘graphlib’ module defines the following exception classes:

 -- Exception: graphlib.CycleError

     Subclass of *note ValueError: 202. raised by *note
     TopologicalSorter.prepare(): 27aa. if cycles exist in the working
     graph.  If multiple cycles exist, only one undefined choice among
     them will be reported and included in the exception.

     The detected cycle can be accessed via the second element in the
     *note args: 56f. attribute of the exception instance and consists
     in a list of nodes, such that each node is, in the graph, an
     immediate predecessor of the next node in the list.  In the
     reported list, the first and the last node will be the same, to
     make it clear that it is cyclic.


File: python.info,  Node: Numeric and Mathematical Modules,  Next: Functional Programming Modules,  Prev: Data Types,  Up: The Python Standard Library

5.9 Numeric and Mathematical Modules
====================================

The modules described in this chapter provide numeric and math-related
functions and data types.  The *note numbers: 9e. module defines an
abstract hierarchy of numeric types.  The *note math: 8e. and *note
cmath: 18. modules contain various mathematical functions for
floating-point and complex numbers.  The *note decimal: 36. module
supports exact representations of decimal numbers, using arbitrary
precision arithmetic.

The following modules are documented in this chapter:

* Menu:

* numbers — Numeric abstract base classes::
* math — Mathematical functions::
* cmath — Mathematical functions for complex numbers::
* decimal — Decimal fixed-point and floating-point arithmetic::
* fractions — Rational numbers::
* random — Generate pseudo-random numbers::
* statistics — Mathematical statistics functions::


File: python.info,  Node: numbers — Numeric abstract base classes,  Next: math — Mathematical functions,  Up: Numeric and Mathematical Modules

5.9.1 ‘numbers’ — Numeric abstract base classes
-----------------------------------------------

'Source code:' Lib/numbers.py(1)

__________________________________________________________________

The ‘numbers’ module ( PEP 3141(2)) defines a hierarchy of numeric *note
abstract base classes: 11fa. which progressively define more operations.
None of the types defined in this module are intended to be
instantiated.

 -- Class: numbers.Number

     The root of the numeric hierarchy.  If you just want to check if an
     argument 'x' is a number, without caring what kind, use
     ‘isinstance(x, Number)’.

* Menu:

* The numeric tower::
* Notes for type implementers::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/numbers.py

   (2) https://peps.python.org/pep-3141/


File: python.info,  Node: The numeric tower,  Next: Notes for type implementers,  Up: numbers — Numeric abstract base classes

5.9.1.1 The numeric tower
.........................

 -- Class: numbers.Complex

     Subclasses of this type describe complex numbers and include the
     operations that work on the built-in *note complex: 2f8. type.
     These are: conversions to ‘complex’ and *note bool: 46b, *note
     real: 27ba, *note imag: 27bb, ‘+’, ‘-’, ‘*’, ‘/’, ‘**’, *note
     abs(): 1e45, *note conjugate(): 27bc, ‘==’, and ‘!=’.  All except
     ‘-’ and ‘!=’ are abstract.

      -- Attribute: real

          Abstract.  Retrieves the real component of this number.

      -- Attribute: imag

          Abstract.  Retrieves the imaginary component of this number.

      -- Method: abstractmethod conjugate ()

          Abstract.  Returns the complex conjugate.  For example,
          ‘(1+3j).conjugate() == (1-3j)’.

 -- Class: numbers.Real

     To *note Complex: 27b9, ‘Real’ adds the operations that work on
     real numbers.

     In short, those are: a conversion to *note float: 2f7, *note
     math.trunc(): 140c, *note round(): 1322, *note math.floor(): 140a,
     *note math.ceil(): 140b, *note divmod(): 9ac, ‘//’, ‘%’, ‘<’, ‘<=’,
     ‘>’, and ‘>=’.

     Real also provides defaults for *note complex(): 2f8, *note real:
     27ba, *note imag: 27bb, and *note conjugate(): 27bc.

 -- Class: numbers.Rational

     Subtypes *note Real: 234e. and adds *note numerator: 27bd. and
     *note denominator: 27be. properties.  It also provides a default
     for *note float(): 2f7.

     The *note numerator: 27bd. and *note denominator: 27be. values
     should be instances of *note Integral: 216f. and should be in
     lowest terms with ‘denominator’ positive.

      -- Attribute: numerator

          Abstract.  The numerator of this rational number.

      -- Attribute: denominator

          Abstract.  The denominator of this rational number.

 -- Class: numbers.Integral

     Subtypes *note Rational: 1306. and adds a conversion to *note int:
     257.  Provides defaults for *note float(): 2f7, *note numerator:
     27bd, and *note denominator: 27be.  Adds abstract methods for *note
     pow(): 9dd. with modulus and bit-string operations: ‘<<’, ‘>>’,
     ‘&’, ‘^’, ‘|’, ‘~’.


File: python.info,  Node: Notes for type implementers,  Prev: The numeric tower,  Up: numbers — Numeric abstract base classes

5.9.1.2 Notes for type implementers
...................................

Implementers should be careful to make equal numbers equal and hash them
to the same values.  This may be subtle if there are two different
extensions of the real numbers.  For example, *note fractions.Fraction:
1e7. implements *note hash(): 5ee. as follows:

     def __hash__(self):
         if self.denominator == 1:
             # Get integers right.
             return hash(self.numerator)
         # Expensive check, but definitely correct.
         if self == float(self):
             return hash(float(self))
         else:
             # Use tuple's hash to avoid a high collision rate on
             # simple fractions.
             return hash((self.numerator, self.denominator))

* Menu:

* Adding More Numeric ABCs::
* Implementing the arithmetic operations::


File: python.info,  Node: Adding More Numeric ABCs,  Next: Implementing the arithmetic operations,  Up: Notes for type implementers

5.9.1.3 Adding More Numeric ABCs
................................

There are, of course, more possible ABCs for numbers, and this would be
a poor hierarchy if it precluded the possibility of adding those.  You
can add ‘MyFoo’ between *note Complex: 27b9. and *note Real: 234e. with:

     class MyFoo(Complex): ...
     MyFoo.register(Real)


File: python.info,  Node: Implementing the arithmetic operations,  Prev: Adding More Numeric ABCs,  Up: Notes for type implementers

5.9.1.4 Implementing the arithmetic operations
..............................................

We want to implement the arithmetic operations so that mixed-mode
operations either call an implementation whose author knew about the
types of both arguments, or convert both to the nearest built in type
and do the operation there.  For subtypes of *note Integral: 216f, this
means that *note __add__(): 2145. and *note __radd__(): 2146. should be
defined as:

     class MyIntegral(Integral):

         def __add__(self, other):
             if isinstance(other, MyIntegral):
                 return do_my_adding_stuff(self, other)
             elif isinstance(other, OtherTypeIKnowAbout):
                 return do_my_other_adding_stuff(self, other)
             else:
                 return NotImplemented

         def __radd__(self, other):
             if isinstance(other, MyIntegral):
                 return do_my_adding_stuff(other, self)
             elif isinstance(other, OtherTypeIKnowAbout):
                 return do_my_other_adding_stuff(other, self)
             elif isinstance(other, Integral):
                 return int(other) + int(self)
             elif isinstance(other, Real):
                 return float(other) + float(self)
             elif isinstance(other, Complex):
                 return complex(other) + complex(self)
             else:
                 return NotImplemented

There are 5 different cases for a mixed-type operation on subclasses of
*note Complex: 27b9.  I’ll refer to all of the above code that doesn’t
refer to ‘MyIntegral’ and ‘OtherTypeIKnowAbout’ as “boilerplate”.  ‘a’
will be an instance of ‘A’, which is a subtype of ‘Complex’ (‘a : A <:
Complex’), and ‘b : B <: Complex’.  I’ll consider ‘a + b’:

  1. If ‘A’ defines an *note __add__(): 2145. which accepts ‘b’, all is
     well.

  2. If ‘A’ falls back to the boilerplate code, and it were to return a
     value from *note __add__(): 2145, we’d miss the possibility that
     ‘B’ defines a more intelligent *note __radd__(): 2146, so the
     boilerplate should return *note NotImplemented: 7d6. from
     ‘__add__()’.  (Or ‘A’ may not implement ‘__add__()’ at all.)

  3. Then ‘B’’s *note __radd__(): 2146. gets a chance.  If it accepts
     ‘a’, all is well.

  4. If it falls back to the boilerplate, there are no more possible
     methods to try, so this is where the default implementation should
     live.

  5. If ‘B <: A’, Python tries ‘B.__radd__’ before ‘A.__add__’.  This is
     ok, because it was implemented with knowledge of ‘A’, so it can
     handle those instances before delegating to *note Complex: 27b9.

If ‘A <: Complex’ and ‘B <: Real’ without sharing any other knowledge,
then the appropriate shared operation is the one involving the built in
*note complex: 2f8, and both *note __radd__(): 2146. s land there, so
‘a+b == b+a’.

Because most of the operations on any given type will be very similar,
it can be useful to define a helper function which generates the forward
and reverse instances of any given operator.  For example, *note
fractions.Fraction: 1e7. uses:

     def _operator_fallbacks(monomorphic_operator, fallback_operator):
         def forward(a, b):
             if isinstance(b, (int, Fraction)):
                 return monomorphic_operator(a, b)
             elif isinstance(b, float):
                 return fallback_operator(float(a), b)
             elif isinstance(b, complex):
                 return fallback_operator(complex(a), b)
             else:
                 return NotImplemented
         forward.__name__ = '__' + fallback_operator.__name__ + '__'
         forward.__doc__ = monomorphic_operator.__doc__

         def reverse(b, a):
             if isinstance(a, Rational):
                 # Includes ints.
                 return monomorphic_operator(a, b)
             elif isinstance(a, Real):
                 return fallback_operator(float(a), float(b))
             elif isinstance(a, Complex):
                 return fallback_operator(complex(a), complex(b))
             else:
                 return NotImplemented
         reverse.__name__ = '__r' + fallback_operator.__name__ + '__'
         reverse.__doc__ = monomorphic_operator.__doc__

         return forward, reverse

     def _add(a, b):
         """a + b"""
         return Fraction(a.numerator * b.denominator +
                         b.numerator * a.denominator,
                         a.denominator * b.denominator)

     __add__, __radd__ = _operator_fallbacks(_add, operator.add)

     # ...


File: python.info,  Node: math — Mathematical functions,  Next: cmath — Mathematical functions for complex numbers,  Prev: numbers — Numeric abstract base classes,  Up: Numeric and Mathematical Modules

5.9.2 ‘math’ — Mathematical functions
-------------------------------------

__________________________________________________________________

This module provides access to common mathematical functions and
constants, including those defined by the C standard.

These functions cannot be used with complex numbers; use the functions
of the same name from the *note cmath: 18. module if you require support
for complex numbers.  The distinction between functions which support
complex numbers and those which don’t is made since most users do not
want to learn quite as much mathematics as required to understand
complex numbers.  Receiving an exception instead of a complex result
allows earlier detection of the unexpected complex number used as a
parameter, so that the programmer can determine how and why it was
generated in the first place.

The following functions are provided by this module.  Except when
explicitly noted otherwise, all return values are floats.

'Number-theoretic functions'

*note comb(n, k): 6d3.                                   Number of ways to choose 'k' items from 'n' items without repetition and without order
                                                         
                                                         
*note factorial(n): 951.                                 'n' factorial
                                                         
                                                         
*note gcd(*integers): 919.                               Greatest common divisor of the integer arguments
                                                         
                                                         
*note isqrt(n): a10.                                     Integer square root of a nonnegative integer 'n'
                                                         
                                                         
*note lcm(*integers): 91a.                               Least common multiple of the integer arguments
                                                         
                                                         
*note perm(n, k): 6d4.                                   Number of ways to choose 'k' items from 'n' items without repetition and with order
                                                         
                                                         
'Floating point arithmetic'

*note ceil(x): 140b.                                     Ceiling of 'x', the smallest integer greater than or equal to 'x'
                                                         
                                                         
*note fabs(x): 27c5.                                     Absolute value of 'x'
                                                         
                                                         
*note floor(x): 140a.                                    Floor of 'x', the largest integer less than or equal to 'x'
                                                         
                                                         
*note fma(x, y, z): 205.                                 Fused multiply-add operation: ‘(x * y) + z’
                                                         
                                                         
*note fmod(x, y): 2220.                                  Remainder of division ‘x / y’
                                                         
                                                         
*note modf(x): 27c6.                                     Fractional and integer parts of 'x'
                                                         
                                                         
*note remainder(x, y): b6e.                              Remainder of 'x' with respect to 'y'
                                                         
                                                         
*note trunc(x): 140c.                                    Integer part of 'x'
                                                         
                                                         
'Floating point manipulation functions'

*note copysign(x, y): 1421.                              Magnitude (absolute value) of 'x' with the sign of 'y'
                                                         
                                                         
*note frexp(x): 27c7.                                    Mantissa and exponent of 'x'
                                                         
                                                         
*note isclose(a, b, rel_tol, abs_tol): dde.              Check if the values 'a' and 'b' are close to each other
                                                         
                                                         
*note isfinite(x): 1230.                                 Check if 'x' is neither an infinity nor a NaN
                                                         
                                                         
*note isinf(x): 141f.                                    Check if 'x' is a positive or negative infinity
                                                         
                                                         
*note isnan(x): 1420.                                    Check if 'x' is a NaN (not a number)
                                                         
                                                         
*note ldexp(x, i): 164a.                                 ‘x * (2**i)’, inverse of function *note frexp(): 27c7.
                                                         
                                                         
*note nextafter(x, y, steps): 49b.                       Floating-point value 'steps' steps after 'x' towards 'y'
                                                         
                                                         
*note ulp(x): 91b.                                       Value of the least significant bit of 'x'
                                                         
                                                         
'Power, exponential and logarithmic functions'

*note cbrt(x): 664.                                      Cube root of 'x'
                                                         
                                                         
*note exp(x): 135d.                                      'e' raised to the power 'x'
                                                         
                                                         
*note exp2(x): 663.                                      '2' raised to the power 'x'
                                                         
                                                         
*note expm1(x): 1231.                                    'e' raised to the power 'x', minus 1
                                                         
                                                         
*note log(x, base): 150f.                                Logarithm of 'x' to the given base ('e' by default)
                                                         
                                                         
*note log1p(x): 1426.                                    Natural logarithm of '1+x' (base 'e')
                                                         
                                                         
*note log2(x): 111f.                                     Base-2 logarithm of 'x'
                                                         
                                                         
*note log10(x): 27c8.                                    Base-10 logarithm of 'x'
                                                         
                                                         
*note pow(x, y): 665.                                    'x' raised to the power 'y'
                                                         
                                                         
*note sqrt(x): a11.                                      Square root of 'x'
                                                         
                                                         
'Summation and product functions'

*note dist(p, q): a0d.                                   Euclidean distance between two points 'p' and 'q' given as an iterable of coordinates
                                                         
                                                         
*note fsum(iterable): 1422.                              Sum of values in the input 'iterable'
                                                         
                                                         
*note hypot(*coordinates): a0e.                          Euclidean norm of an iterable of coordinates
                                                         
                                                         
*note prod(iterable, start): a0f.                        Product of elements in the input 'iterable' with a 'start' value
                                                         
                                                         
*note sumprod(p, q): 49a.                                Sum of products from two iterables 'p' and 'q'
                                                         
                                                         
'Angular conversion'

*note degrees(x): 27c9.                                  Convert angle 'x' from radians to degrees
                                                         
                                                         
*note radians(x): 27ca.                                  Convert angle 'x' from degrees to radians
                                                         
                                                         
'Trigonometric functions'

*note acos(x): 27cb.                                     Arc cosine of 'x'
                                                         
                                                         
*note asin(x): 27cc.                                     Arc sine of 'x'
                                                         
                                                         
*note atan(x): 27cd.                                     Arc tangent of 'x'
                                                         
                                                         
*note atan2(y, x): 27ce.                                 ‘atan(y / x)’
                                                         
                                                         
*note cos(x): 150e.                                      Cosine of 'x'
                                                         
                                                         
*note sin(x): 150d.                                      Sine of 'x'
                                                         
                                                         
*note tan(x): 27cf.                                      Tangent of 'x'
                                                         
                                                         
'Hyperbolic functions'

*note acosh(x): 1423.                                    Inverse hyperbolic cosine of 'x'
                                                         
                                                         
*note asinh(x): 1424.                                    Inverse hyperbolic sine of 'x'
                                                         
                                                         
*note atanh(x): 1425.                                    Inverse hyperbolic tangent of 'x'
                                                         
                                                         
*note cosh(x): 27d0.                                     Hyperbolic cosine of 'x'
                                                         
                                                         
*note sinh(x): 27d1.                                     Hyperbolic sine of 'x'
                                                         
                                                         
*note tanh(x): 27d2.                                     Hyperbolic tangent of 'x'
                                                         
                                                         
'Special functions'

*note erf(x): bf9.                                       Error function(1) at 'x'
                                                         
                                                         
*note erfc(x): bfa.                                      Complementary error function(2) at 'x'
                                                         
                                                         
*note gamma(x): 1232.                                    Gamma function(3) at 'x'
                                                         
                                                         
*note lgamma(x): 1233.                                   Natural logarithm of the absolute value of the Gamma function(4) at 'x'
                                                         
                                                         
'Constants'

*note pi: 27d3.                                          'π' = 3.141592…
                                                         
                                                         
*note e: 27d4.                                           'e' = 2.718281…
                                                         
                                                         
*note tau: 27d5.                                         'τ' = 2'π' = 6.283185…
                                                         
                                                         
*note inf: ca7.                                          Positive infinity
                                                         
                                                         
*note nan: 666.                                          “Not a number” (NaN)
                                                         

* Menu:

* Number-theoretic functions::
* Floating point arithmetic::
* Floating point manipulation functions::
* Power, exponential and logarithmic functions: Power exponential and logarithmic functions.
* Summation and product functions::
* Angular conversion::
* Trigonometric functions::
* Hyperbolic functions::
* Special functions::
* Constants: Constants<2>.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Error_function

   (2) https://en.wikipedia.org/wiki/Error_function

   (3) https://en.wikipedia.org/wiki/Gamma_function

   (4) https://en.wikipedia.org/wiki/Gamma_function


File: python.info,  Node: Number-theoretic functions,  Next: Floating point arithmetic,  Up: math — Mathematical functions

5.9.2.1 Number-theoretic functions
..................................

 -- Function: math.comb (n, k)

     Return the number of ways to choose 'k' items from 'n' items
     without repetition and without order.

     Evaluates to ‘n! / (k! * (n - k)!)’ when ‘k <= n’ and evaluates to
     zero when ‘k > n’.

     Also called the binomial coefficient because it is equivalent to
     the coefficient of k-th term in polynomial expansion of ‘(1 + x)ⁿ’.

     Raises *note TypeError: 2c3. if either of the arguments are not
     integers.  Raises *note ValueError: 202. if either of the arguments
     are negative.

     Added in version 3.8.

 -- Function: math.factorial (n)

     Return factorial of the nonnegative integer 'n'.

     Changed in version 3.10: Floats with integral values (like ‘5.0’)
     are no longer accepted.

 -- Function: math.gcd (*integers)

     Return the greatest common divisor of the specified integer
     arguments.  If any of the arguments is nonzero, then the returned
     value is the largest positive integer that is a divisor of all
     arguments.  If all arguments are zero, then the returned value is
     ‘0’.  ‘gcd()’ without arguments returns ‘0’.

     Added in version 3.5.

     Changed in version 3.9: Added support for an arbitrary number of
     arguments.  Formerly, only two arguments were supported.

 -- Function: math.isqrt (n)

     Return the integer square root of the nonnegative integer 'n'.
     This is the floor of the exact square root of 'n', or equivalently
     the greatest integer 'a' such that 'a'² ≤ 'n'.

     For some applications, it may be more convenient to have the least
     integer 'a' such that 'n' ≤ 'a'², or in other words the ceiling of
     the exact square root of 'n'.  For positive 'n', this can be
     computed using ‘a = 1 + isqrt(n - 1)’.

     Added in version 3.8.

 -- Function: math.lcm (*integers)

     Return the least common multiple of the specified integer
     arguments.  If all arguments are nonzero, then the returned value
     is the smallest positive integer that is a multiple of all
     arguments.  If any of the arguments is zero, then the returned
     value is ‘0’.  ‘lcm()’ without arguments returns ‘1’.

     Added in version 3.9.

 -- Function: math.perm (n, k=None)

     Return the number of ways to choose 'k' items from 'n' items
     without repetition and with order.

     Evaluates to ‘n! / (n - k)!’ when ‘k <= n’ and evaluates to zero
     when ‘k > n’.

     If 'k' is not specified or is ‘None’, then 'k' defaults to 'n' and
     the function returns ‘n!’.

     Raises *note TypeError: 2c3. if either of the arguments are not
     integers.  Raises *note ValueError: 202. if either of the arguments
     are negative.

     Added in version 3.8.


File: python.info,  Node: Floating point arithmetic,  Next: Floating point manipulation functions,  Prev: Number-theoretic functions,  Up: math — Mathematical functions

5.9.2.2 Floating point arithmetic
.................................

 -- Function: math.ceil (x)

     Return the ceiling of 'x', the smallest integer greater than or
     equal to 'x'.  If 'x' is not a float, delegates to *note
     x.__ceil__: 216e, which should return an *note Integral: 216f.
     value.

 -- Function: math.fabs (x)

     Return the absolute value of 'x'.

 -- Function: math.floor (x)

     Return the floor of 'x', the largest integer less than or equal to
     'x'.  If 'x' is not a float, delegates to *note x.__floor__: 216d,
     which should return an *note Integral: 216f. value.

 -- Function: math.fma (x, y, z)

     Fused multiply-add operation.  Return ‘(x * y) + z’, computed as
     though with infinite precision and range followed by a single round
     to the ‘float’ format.  This operation often provides better
     accuracy than the direct expression ‘(x * y) + z’.

     This function follows the specification of the fusedMultiplyAdd
     operation described in the IEEE 754 standard.  The standard leaves
     one case implementation-defined, namely the result of ‘fma(0, inf,
     nan)’ and ‘fma(inf, 0, nan)’.  In these cases, ‘math.fma’ returns a
     NaN, and does not raise any exception.

     Added in version 3.13.

 -- Function: math.fmod (x, y)

     Return the floating-point remainder of ‘x / y’, as defined by the
     platform C library function ‘fmod(x, y)’.  Note that the Python
     expression ‘x % y’ may not return the same result.  The intent of
     the C standard is that ‘fmod(x, y)’ be exactly (mathematically; to
     infinite precision) equal to ‘x - n*y’ for some integer 'n' such
     that the result has the same sign as 'x' and magnitude less than
     ‘abs(y)’.  Python’s ‘x % y’ returns a result with the sign of 'y'
     instead, and may not be exactly computable for float arguments.
     For example, ‘fmod(-1e-100, 1e100)’ is ‘-1e-100’, but the result of
     Python’s ‘-1e-100 % 1e100’ is ‘1e100-1e-100’, which cannot be
     represented exactly as a float, and rounds to the surprising
     ‘1e100’.  For this reason, function ‘fmod()’ is generally preferred
     when working with floats, while Python’s ‘x % y’ is preferred when
     working with integers.

 -- Function: math.modf (x)

     Return the fractional and integer parts of 'x'.  Both results carry
     the sign of 'x' and are floats.

     Note that ‘modf()’ has a different call/return pattern than its C
     equivalents: it takes a single argument and return a pair of
     values, rather than returning its second return value through an
     ‘output parameter’ (there is no such thing in Python).

 -- Function: math.remainder (x, y)

     Return the IEEE 754-style remainder of 'x' with respect to 'y'.
     For finite 'x' and finite nonzero 'y', this is the difference ‘x -
     n*y’, where ‘n’ is the closest integer to the exact value of the
     quotient ‘x / y’.  If ‘x / y’ is exactly halfway between two
     consecutive integers, the nearest 'even' integer is used for ‘n’.
     The remainder ‘r = remainder(x, y)’ thus always satisfies ‘abs(r)
     <= 0.5 * abs(y)’.

     Special cases follow IEEE 754: in particular, ‘remainder(x,
     math.inf)’ is 'x' for any finite 'x', and ‘remainder(x, 0)’ and
     ‘remainder(math.inf, x)’ raise *note ValueError: 202. for any
     non-NaN 'x'.  If the result of the remainder operation is zero,
     that zero will have the same sign as 'x'.

     On platforms using IEEE 754 binary floating point, the result of
     this operation is always exactly representable: no rounding error
     is introduced.

     Added in version 3.7.

 -- Function: math.trunc (x)

     Return 'x' with the fractional part removed, leaving the integer
     part.  This rounds toward 0: ‘trunc()’ is equivalent to *note
     floor(): 140a. for positive 'x', and equivalent to *note ceil():
     140b. for negative 'x'.  If 'x' is not a float, delegates to *note
     x.__trunc__: 71e, which should return an *note Integral: 216f.
     value.

For the *note ceil(): 140b, *note floor(): 140a, and *note modf(): 27c6.
functions, note that 'all' floating-point numbers of sufficiently large
magnitude are exact integers.  Python floats typically carry no more
than 53 bits of precision (the same as the platform C double type), in
which case any float 'x' with ‘abs(x) >= 2**52’ necessarily has no
fractional bits.


File: python.info,  Node: Floating point manipulation functions,  Next: Power exponential and logarithmic functions,  Prev: Floating point arithmetic,  Up: math — Mathematical functions

5.9.2.3 Floating point manipulation functions
.............................................

 -- Function: math.copysign (x, y)

     Return a float with the magnitude (absolute value) of 'x' but the
     sign of 'y'.  On platforms that support signed zeros,
     ‘copysign(1.0, -0.0)’ returns '-1.0'.

 -- Function: math.frexp (x)

     Return the mantissa and exponent of 'x' as the pair ‘(m, e)’.  'm'
     is a float and 'e' is an integer such that ‘x == m * 2**e’ exactly.
     If 'x' is zero, returns ‘(0.0, 0)’, otherwise ‘0.5 <= abs(m) < 1’.
     This is used to “pick apart” the internal representation of a float
     in a portable way.

     Note that ‘frexp()’ has a different call/return pattern than its C
     equivalents: it takes a single argument and return a pair of
     values, rather than returning its second return value through an
     ‘output parameter’ (there is no such thing in Python).

 -- Function: math.isclose (a, b, *, rel_tol=1e-09, abs_tol=0.0)

     Return ‘True’ if the values 'a' and 'b' are close to each other and
     ‘False’ otherwise.

     Whether or not two values are considered close is determined
     according to given absolute and relative tolerances.  If no errors
     occur, the result will be: ‘abs(a-b) <= max(rel_tol * max(abs(a),
     abs(b)), abs_tol)’.

     'rel_tol' is the relative tolerance – it is the maximum allowed
     difference between 'a' and 'b', relative to the larger absolute
     value of 'a' or 'b'.  For example, to set a tolerance of 5%, pass
     ‘rel_tol=0.05’.  The default tolerance is ‘1e-09’, which assures
     that the two values are the same within about 9 decimal digits.
     'rel_tol' must be nonnegative and less than ‘1.0’.

     'abs_tol' is the absolute tolerance; it defaults to ‘0.0’ and it
     must be nonnegative.  When comparing ‘x’ to ‘0.0’, ‘isclose(x, 0)’
     is computed as ‘abs(x) <= rel_tol * abs(x)’, which is ‘False’ for
     any nonzero ‘x’ and 'rel_tol' less than ‘1.0’.  So add an
     appropriate positive 'abs_tol' argument to the call.

     The IEEE 754 special values of ‘NaN’, ‘inf’, and ‘-inf’ will be
     handled according to IEEE rules.  Specifically, ‘NaN’ is not
     considered close to any other value, including ‘NaN’.  ‘inf’ and
     ‘-inf’ are only considered close to themselves.

     Added in version 3.5.

     See also
     ........

     PEP 485(1) – A function for testing approximate equality

 -- Function: math.isfinite (x)

     Return ‘True’ if 'x' is neither an infinity nor a NaN, and ‘False’
     otherwise.  (Note that ‘0.0’ 'is' considered finite.)

     Added in version 3.2.

 -- Function: math.isinf (x)

     Return ‘True’ if 'x' is a positive or negative infinity, and
     ‘False’ otherwise.

 -- Function: math.isnan (x)

     Return ‘True’ if 'x' is a NaN (not a number), and ‘False’
     otherwise.

 -- Function: math.ldexp (x, i)

     Return ‘x * (2**i)’.  This is essentially the inverse of function
     *note frexp(): 27c7.

 -- Function: math.nextafter (x, y, steps=1)

     Return the floating-point value 'steps' steps after 'x' towards
     'y'.

     If 'x' is equal to 'y', return 'y', unless 'steps' is zero.

     Examples:

        * ‘math.nextafter(x, math.inf)’ goes up: towards positive
          infinity.

        * ‘math.nextafter(x, -math.inf)’ goes down: towards minus
          infinity.

        * ‘math.nextafter(x, 0.0)’ goes towards zero.

        * ‘math.nextafter(x, math.copysign(math.inf, x))’ goes away from
          zero.

     See also *note math.ulp(): 91b.

     Added in version 3.9.

     Changed in version 3.12: Added the 'steps' argument.

 -- Function: math.ulp (x)

     Return the value of the least significant bit of the float 'x':

        * If 'x' is a NaN (not a number), return 'x'.

        * If 'x' is negative, return ‘ulp(-x)’.

        * If 'x' is a positive infinity, return 'x'.

        * If 'x' is equal to zero, return the smallest positive
          'denormalized' representable float (smaller than the minimum
          positive 'normalized' float, *note sys.float_info.min: 1b7b.).

        * If 'x' is equal to the largest positive representable float,
          return the value of the least significant bit of 'x', such
          that the first float smaller than 'x' is ‘x - ulp(x)’.

        * Otherwise ('x' is a positive finite number), return the value
          of the least significant bit of 'x', such that the first float
          bigger than 'x' is ‘x + ulp(x)’.

     ULP stands for “Unit in the Last Place”.

     See also *note math.nextafter(): 49b. and *note
     sys.float_info.epsilon: 1b7b.

     Added in version 3.9.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0485/


File: python.info,  Node: Power exponential and logarithmic functions,  Next: Summation and product functions,  Prev: Floating point manipulation functions,  Up: math — Mathematical functions

5.9.2.4 Power, exponential and logarithmic functions
....................................................

 -- Function: math.cbrt (x)

     Return the cube root of 'x'.

     Added in version 3.11.

 -- Function: math.exp (x)

     Return 'e' raised to the power 'x', where 'e' = 2.718281… is the
     base of natural logarithms.  This is usually more accurate than
     ‘math.e ** x’ or ‘pow(math.e, x)’.

 -- Function: math.exp2 (x)

     Return '2' raised to the power 'x'.

     Added in version 3.11.

 -- Function: math.expm1 (x)

     Return 'e' raised to the power 'x', minus 1.  Here 'e' is the base
     of natural logarithms.  For small floats 'x', the subtraction in
     ‘exp(x) - 1’ can result in a significant loss of precision(1); the
     ‘expm1()’ function provides a way to compute this quantity to full
     precision:

          >>> from math import exp, expm1
          >>> exp(1e-5) - 1  # gives result accurate to 11 places
          1.0000050000069649e-05
          >>> expm1(1e-5)    # result accurate to full precision
          1.0000050000166668e-05

     Added in version 3.2.

 -- Function: math.log (x[, base])

     With one argument, return the natural logarithm of 'x' (to base
     'e').

     With two arguments, return the logarithm of 'x' to the given
     'base', calculated as ‘log(x)/log(base)’.

 -- Function: math.log1p (x)

     Return the natural logarithm of '1+x' (base 'e').  The result is
     calculated in a way which is accurate for 'x' near zero.

 -- Function: math.log2 (x)

     Return the base-2 logarithm of 'x'.  This is usually more accurate
     than ‘log(x, 2)’.

     Added in version 3.3.

     See also
     ........

     *note int.bit_length(): 2352. returns the number of bits necessary
     to represent an integer in binary, excluding the sign and leading
     zeros.

 -- Function: math.log10 (x)

     Return the base-10 logarithm of 'x'.  This is usually more accurate
     than ‘log(x, 10)’.

 -- Function: math.pow (x, y)

     Return 'x' raised to the power 'y'.  Exceptional cases follow the
     IEEE 754 standard as far as possible.  In particular, ‘pow(1.0, x)’
     and ‘pow(x, 0.0)’ always return ‘1.0’, even when 'x' is a zero or a
     NaN. If both 'x' and 'y' are finite, 'x' is negative, and 'y' is
     not an integer then ‘pow(x, y)’ is undefined, and raises *note
     ValueError: 202.

     Unlike the built-in ‘**’ operator, *note math.pow(): 665. converts
     both its arguments to type *note float: 2f7.  Use ‘**’ or the
     built-in ‘pow()’ function for computing exact integer powers.

     Changed in version 3.11: The special cases ‘pow(0.0, -inf)’ and
     ‘pow(-0.0, -inf)’ were changed to return ‘inf’ instead of raising
     *note ValueError: 202, for consistency with IEEE 754.

 -- Function: math.sqrt (x)

     Return the square root of 'x'.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Loss_of_significance


File: python.info,  Node: Summation and product functions,  Next: Angular conversion,  Prev: Power exponential and logarithmic functions,  Up: math — Mathematical functions

5.9.2.5 Summation and product functions
.......................................

 -- Function: math.dist (p, q)

     Return the Euclidean distance between two points 'p' and 'q', each
     given as a sequence (or iterable) of coordinates.  The two points
     must have the same dimension.

     Roughly equivalent to:

          sqrt(sum((px - qx) ** 2.0 for px, qx in zip(p, q)))

     Added in version 3.8.

 -- Function: math.fsum (iterable)

     Return an accurate floating-point sum of values in the iterable.
     Avoids loss of precision by tracking multiple intermediate partial
     sums.

     The algorithm’s accuracy depends on IEEE-754 arithmetic guarantees
     and the typical case where the rounding mode is half-even.  On some
     non-Windows builds, the underlying C library uses extended
     precision addition and may occasionally double-round an
     intermediate sum causing it to be off in its least significant bit.

     For further discussion and two alternative approaches, see the ASPN
     cookbook recipes for accurate floating-point summation(1).

 -- Function: math.hypot (*coordinates)

     Return the Euclidean norm, ‘sqrt(sum(x**2 for x in coordinates))’.
     This is the length of the vector from the origin to the point given
     by the coordinates.

     For a two dimensional point ‘(x, y)’, this is equivalent to
     computing the hypotenuse of a right triangle using the Pythagorean
     theorem, ‘sqrt(x*x + y*y)’.

     Changed in version 3.8: Added support for n-dimensional points.
     Formerly, only the two dimensional case was supported.

     Changed in version 3.10: Improved the algorithm’s accuracy so that
     the maximum error is under 1 ulp (unit in the last place).  More
     typically, the result is almost always correctly rounded to within
     1/2 ulp.

 -- Function: math.prod (iterable, *, start=1)

     Calculate the product of all the elements in the input 'iterable'.
     The default 'start' value for the product is ‘1’.

     When the iterable is empty, return the start value.  This function
     is intended specifically for use with numeric values and may reject
     non-numeric types.

     Added in version 3.8.

 -- Function: math.sumprod (p, q)

     Return the sum of products of values from two iterables 'p' and
     'q'.

     Raises *note ValueError: 202. if the inputs do not have the same
     length.

     Roughly equivalent to:

          sum(itertools.starmap(operator.mul, zip(p, q, strict=True)))

     For float and mixed int/float inputs, the intermediate products and
     sums are computed with extended precision.

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) 
https://code.activestate.com/recipes/393090-binary-floating-point-summation-accurate-to-full-p/


File: python.info,  Node: Angular conversion,  Next: Trigonometric functions,  Prev: Summation and product functions,  Up: math — Mathematical functions

5.9.2.6 Angular conversion
..........................

 -- Function: math.degrees (x)

     Convert angle 'x' from radians to degrees.

 -- Function: math.radians (x)

     Convert angle 'x' from degrees to radians.


File: python.info,  Node: Trigonometric functions,  Next: Hyperbolic functions,  Prev: Angular conversion,  Up: math — Mathematical functions

5.9.2.7 Trigonometric functions
...............................

 -- Function: math.acos (x)

     Return the arc cosine of 'x', in radians.  The result is between
     ‘0’ and ‘pi’.

 -- Function: math.asin (x)

     Return the arc sine of 'x', in radians.  The result is between
     ‘-pi/2’ and ‘pi/2’.

 -- Function: math.atan (x)

     Return the arc tangent of 'x', in radians.  The result is between
     ‘-pi/2’ and ‘pi/2’.

 -- Function: math.atan2 (y, x)

     Return ‘atan(y / x)’, in radians.  The result is between ‘-pi’ and
     ‘pi’.  The vector in the plane from the origin to point ‘(x, y)’
     makes this angle with the positive X axis.  The point of ‘atan2()’
     is that the signs of both inputs are known to it, so it can compute
     the correct quadrant for the angle.  For example, ‘atan(1)’ and
     ‘atan2(1, 1)’ are both ‘pi/4’, but ‘atan2(-1, -1)’ is ‘-3*pi/4’.

 -- Function: math.cos (x)

     Return the cosine of 'x' radians.

 -- Function: math.sin (x)

     Return the sine of 'x' radians.

 -- Function: math.tan (x)

     Return the tangent of 'x' radians.


File: python.info,  Node: Hyperbolic functions,  Next: Special functions,  Prev: Trigonometric functions,  Up: math — Mathematical functions

5.9.2.8 Hyperbolic functions
............................

Hyperbolic functions(1) are analogs of trigonometric functions that are
based on hyperbolas instead of circles.

 -- Function: math.acosh (x)

     Return the inverse hyperbolic cosine of 'x'.

 -- Function: math.asinh (x)

     Return the inverse hyperbolic sine of 'x'.

 -- Function: math.atanh (x)

     Return the inverse hyperbolic tangent of 'x'.

 -- Function: math.cosh (x)

     Return the hyperbolic cosine of 'x'.

 -- Function: math.sinh (x)

     Return the hyperbolic sine of 'x'.

 -- Function: math.tanh (x)

     Return the hyperbolic tangent of 'x'.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Hyperbolic_functions


File: python.info,  Node: Special functions,  Next: Constants<2>,  Prev: Hyperbolic functions,  Up: math — Mathematical functions

5.9.2.9 Special functions
.........................

 -- Function: math.erf (x)

     Return the error function(1) at 'x'.

     The ‘erf()’ function can be used to compute traditional statistical
     functions such as the cumulative standard normal distribution(2):

          def phi(x):
              'Cumulative distribution function for the standard normal distribution'
              return (1.0 + erf(x / sqrt(2.0))) / 2.0

     Added in version 3.2.

 -- Function: math.erfc (x)

     Return the complementary error function at 'x'.  The complementary
     error function(3) is defined as ‘1.0 - erf(x)’.  It is used for
     large values of 'x' where a subtraction from one would cause a loss
     of significance(4).

     Added in version 3.2.

 -- Function: math.gamma (x)

     Return the Gamma function(5) at 'x'.

     Added in version 3.2.

 -- Function: math.lgamma (x)

     Return the natural logarithm of the absolute value of the Gamma
     function at 'x'.

     Added in version 3.2.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Error_function

   (2) https://en.wikipedia.org/wiki/Cumulative_distribution_function

   (3) https://en.wikipedia.org/wiki/Error_function

   (4) https://en.wikipedia.org/wiki/Loss_of_significance

   (5) https://en.wikipedia.org/wiki/Gamma_function


File: python.info,  Node: Constants<2>,  Prev: Special functions,  Up: math — Mathematical functions

5.9.2.10 Constants
..................

 -- Data: math.pi

     The mathematical constant 'π' = 3.141592…, to available precision.

 -- Data: math.e

     The mathematical constant 'e' = 2.718281…, to available precision.

 -- Data: math.tau

     The mathematical constant 'τ' = 6.283185…, to available precision.
     Tau is a circle constant equal to 2'π', the ratio of a circle’s
     circumference to its radius.  To learn more about Tau, check out Vi
     Hart’s video Pi is (still) Wrong(1), and start celebrating Tau
     day(2) by eating twice as much pie!

     Added in version 3.6.

 -- Data: math.inf

     A floating-point positive infinity.  (For negative infinity, use
     ‘-math.inf’.)  Equivalent to the output of ‘float('inf')’.

     Added in version 3.5.

 -- Data: math.nan

     A floating-point “not a number” (NaN) value.  Equivalent to the
     output of ‘float('nan')’.  Due to the requirements of the IEEE-754
     standard(3), ‘math.nan’ and ‘float('nan')’ are not considered to
     equal to any other numeric value, including themselves.  To check
     whether a number is a NaN, use the *note isnan(): 1420. function to
     test for NaNs instead of ‘is’ or ‘==’.  Example:

          >>> import math
          >>> math.nan == math.nan
          False
          >>> float('nan') == float('nan')
          False
          >>> math.isnan(math.nan)
          True
          >>> math.isnan(float('nan'))
          True

     Added in version 3.5.

     Changed in version 3.11: It is now always available.

'CPython implementation detail:' The ‘math’ module consists mostly of
thin wrappers around the platform C math library functions.  Behavior in
exceptional cases follows Annex F of the C99 standard where appropriate.
The current implementation will raise *note ValueError: 202. for invalid
operations like ‘sqrt(-1.0)’ or ‘log(0.0)’ (where C99 Annex F recommends
signaling invalid operation or divide-by-zero), and *note OverflowError:
888. for results that overflow (for example, ‘exp(1000.0)’).  A NaN will
not be returned from any of the functions above unless one or more of
the input arguments was a NaN; in that case, most functions will return
a NaN, but (again following C99 Annex F) there are some exceptions to
this rule, for example ‘pow(float('nan'), 0.0)’ or ‘hypot(float('nan'),
float('inf'))’.

Note that Python makes no effort to distinguish signaling NaNs from
quiet NaNs, and behavior for signaling NaNs remains unspecified.
Typical behavior is to treat all NaNs as though they were quiet.

See also
........

Module *note cmath: 18.

     Complex number versions of many of these functions.

   ---------- Footnotes ----------

   (1) https://vimeo.com/147792667

   (2) https://tauday.com/

   (3) https://en.wikipedia.org/wiki/IEEE_754


File: python.info,  Node: cmath — Mathematical functions for complex numbers,  Next: decimal — Decimal fixed-point and floating-point arithmetic,  Prev: math — Mathematical functions,  Up: Numeric and Mathematical Modules

5.9.3 ‘cmath’ — Mathematical functions for complex numbers
----------------------------------------------------------

__________________________________________________________________

This module provides access to mathematical functions for complex
numbers.  The functions in this module accept integers, floating-point
numbers or complex numbers as arguments.  They will also accept any
Python object that has either a *note __complex__(): 5ea. or a *note
__float__(): 9d7. method: these methods are used to convert the object
to a complex or floating-point number, respectively, and the function is
then applied to the result of the conversion.

     Note: For functions involving branch cuts, we have the problem of
     deciding how to define those functions on the cut itself.
     Following Kahan’s “Branch cuts for complex elementary functions”
     paper, as well as Annex G of C99 and later C standards, we use the
     sign of zero to distinguish one side of the branch cut from the
     other: for a branch cut along (a portion of) the real axis we look
     at the sign of the imaginary part, while for a branch cut along the
     imaginary axis we look at the sign of the real part.

     For example, the *note cmath.sqrt(): 27e3. function has a branch
     cut along the negative real axis.  An argument of ‘complex(-2.0,
     -0.0)’ is treated as though it lies 'below' the branch cut, and so
     gives a result on the negative imaginary axis:

          >>> cmath.sqrt(complex(-2.0, -0.0))
          -1.4142135623730951j

     But an argument of ‘complex(-2.0, 0.0)’ is treated as though it
     lies above the branch cut:

          >>> cmath.sqrt(complex(-2.0, 0.0))
          1.4142135623730951j

'Conversions to and from polar coordinates'

*note phase(z): 27e4.                                    Return the phase of 'z'
                                                         
                                                         
*note polar(z): 27e5.                                    Return the representation of 'z' in polar coordinates
                                                         
                                                         
*note rect(r, phi): 27e6.                                Return the complex number 'z' with polar coordinates 'r' and 'phi'
                                                         
                                                         
'Power and logarithmic functions'

*note exp(z): 27e7.                                      Return 'e' raised to the power 'z'
                                                         
                                                         
*note log(z[, base]): 27e8.                              Return the logarithm of 'z' to the given 'base' ('e' by default)
                                                         
                                                         
*note log10(z): 27e9.                                    Return the base-10 logarithm of 'z'
                                                         
                                                         
*note sqrt(z): 27e3.                                     Return the square root of 'z'
                                                         
                                                         
'Trigonometric functions'

*note acos(z): 27ea.                                     Return the arc cosine of 'z'
                                                         
                                                         
*note asin(z): 27eb.                                     Return the arc sine of 'z'
                                                         
                                                         
*note atan(z): 27ec.                                     Return the arc tangent of 'z'
                                                         
                                                         
*note cos(z): 27ed.                                      Return the cosine of 'z'
                                                         
                                                         
*note sin(z): 27ee.                                      Return the sine of 'z'
                                                         
                                                         
*note tan(z): 27ef.                                      Return the tangent of 'z'
                                                         
                                                         
'Hyperbolic functions'

*note acosh(z): 27f0.                                    Return the inverse hyperbolic cosine of 'z'
                                                         
                                                         
*note asinh(z): 27f1.                                    Return the inverse hyperbolic sine of 'z'
                                                         
                                                         
*note atanh(z): 27f2.                                    Return the inverse hyperbolic tangent of 'z'
                                                         
                                                         
*note cosh(z): 27f3.                                     Return the hyperbolic cosine of 'z'
                                                         
                                                         
*note sinh(z): 27f4.                                     Return the hyperbolic sine of 'z'
                                                         
                                                         
*note tanh(z): 27f5.                                     Return the hyperbolic tangent of 'z'
                                                         
                                                         
'Classification functions'

*note isfinite(z): 27f6.                                 Check if all components of 'z' are finite
                                                         
                                                         
*note isinf(z): 27f7.                                    Check if any component of 'z' is infinite
                                                         
                                                         
*note isnan(z): 27f8.                                    Check if any component of 'z' is a NaN
                                                         
                                                         
*note isclose(a, b, *, rel_tol, abs_tol): ddf.           Check if the values 'a' and 'b' are close to each other
                                                         
                                                         
'Constants'

*note pi: 27f9.                                          'π' = 3.141592…
                                                         
                                                         
*note e: 27fa.                                           'e' = 2.718281…
                                                         
                                                         
*note tau: ca4.                                          'τ' = 2'π' = 6.283185…
                                                         
                                                         
*note inf: ca5.                                          Positive infinity
                                                         
                                                         
*note infj: ca8.                                         Pure imaginary infinity
                                                         
                                                         
*note nan: ca6.                                          “Not a number” (NaN)
                                                         
                                                         
*note nanj: ca9.                                         Pure imaginary NaN
                                                         

* Menu:

* Conversions to and from polar coordinates::
* Power and logarithmic functions::
* Trigonometric functions: Trigonometric functions<2>.
* Hyperbolic functions: Hyperbolic functions<2>.
* Classification functions::
* Constants: Constants<3>.


File: python.info,  Node: Conversions to and from polar coordinates,  Next: Power and logarithmic functions,  Up: cmath — Mathematical functions for complex numbers

5.9.3.1 Conversions to and from polar coordinates
.................................................

A Python complex number ‘z’ is stored internally using 'rectangular' or
'Cartesian' coordinates.  It is completely determined by its 'real part'
‘z.real’ and its 'imaginary part' ‘z.imag’.

'Polar coordinates' give an alternative way to represent a complex
number.  In polar coordinates, a complex number 'z' is defined by the
modulus 'r' and the phase angle 'phi'.  The modulus 'r' is the distance
from 'z' to the origin, while the phase 'phi' is the counterclockwise
angle, measured in radians, from the positive x-axis to the line segment
that joins the origin to 'z'.

The following functions can be used to convert from the native
rectangular coordinates to polar coordinates and back.

 -- Function: cmath.phase (z)

     Return the phase of 'z' (also known as the 'argument' of 'z'), as a
     float.  ‘phase(z)’ is equivalent to ‘math.atan2(z.imag, z.real)’.
     The result lies in the range [-'π', 'π'], and the branch cut for
     this operation lies along the negative real axis.  The sign of the
     result is the same as the sign of ‘z.imag’, even when ‘z.imag’ is
     zero:

          >>> phase(complex(-1.0, 0.0))
          3.141592653589793
          >>> phase(complex(-1.0, -0.0))
          -3.141592653589793

     Note: The modulus (absolute value) of a complex number 'z' can be
     computed using the built-in *note abs(): 1e45. function.  There is
     no separate ‘cmath’ module function for this operation.

 -- Function: cmath.polar (z)

     Return the representation of 'z' in polar coordinates.  Returns a
     pair ‘(r, phi)’ where 'r' is the modulus of 'z' and 'phi' is the
     phase of 'z'.  ‘polar(z)’ is equivalent to ‘(abs(z), phase(z))’.

 -- Function: cmath.rect (r, phi)

     Return the complex number 'z' with polar coordinates 'r' and 'phi'.
     Equivalent to ‘complex(r * math.cos(phi), r * math.sin(phi))’.


File: python.info,  Node: Power and logarithmic functions,  Next: Trigonometric functions<2>,  Prev: Conversions to and from polar coordinates,  Up: cmath — Mathematical functions for complex numbers

5.9.3.2 Power and logarithmic functions
.......................................

 -- Function: cmath.exp (z)

     Return 'e' raised to the power 'z', where 'e' is the base of
     natural logarithms.

 -- Function: cmath.log (z[, base])

     Return the logarithm of 'z' to the given 'base'.  If the 'base' is
     not specified, returns the natural logarithm of 'z'.  There is one
     branch cut, from 0 along the negative real axis to -∞.

 -- Function: cmath.log10 (z)

     Return the base-10 logarithm of 'z'.  This has the same branch cut
     as *note log(): 27e8.

 -- Function: cmath.sqrt (z)

     Return the square root of 'z'.  This has the same branch cut as
     *note log(): 27e8.


File: python.info,  Node: Trigonometric functions<2>,  Next: Hyperbolic functions<2>,  Prev: Power and logarithmic functions,  Up: cmath — Mathematical functions for complex numbers

5.9.3.3 Trigonometric functions
...............................

 -- Function: cmath.acos (z)

     Return the arc cosine of 'z'.  There are two branch cuts: One
     extends right from 1 along the real axis to ∞.  The other extends
     left from -1 along the real axis to -∞.

 -- Function: cmath.asin (z)

     Return the arc sine of 'z'.  This has the same branch cuts as *note
     acos(): 27ea.

 -- Function: cmath.atan (z)

     Return the arc tangent of 'z'.  There are two branch cuts: One
     extends from ‘1j’ along the imaginary axis to ‘∞j’.  The other
     extends from ‘-1j’ along the imaginary axis to ‘-∞j’.

 -- Function: cmath.cos (z)

     Return the cosine of 'z'.

 -- Function: cmath.sin (z)

     Return the sine of 'z'.

 -- Function: cmath.tan (z)

     Return the tangent of 'z'.


File: python.info,  Node: Hyperbolic functions<2>,  Next: Classification functions,  Prev: Trigonometric functions<2>,  Up: cmath — Mathematical functions for complex numbers

5.9.3.4 Hyperbolic functions
............................

 -- Function: cmath.acosh (z)

     Return the inverse hyperbolic cosine of 'z'.  There is one branch
     cut, extending left from 1 along the real axis to -∞.

 -- Function: cmath.asinh (z)

     Return the inverse hyperbolic sine of 'z'.  There are two branch
     cuts: One extends from ‘1j’ along the imaginary axis to ‘∞j’.  The
     other extends from ‘-1j’ along the imaginary axis to ‘-∞j’.

 -- Function: cmath.atanh (z)

     Return the inverse hyperbolic tangent of 'z'.  There are two branch
     cuts: One extends from ‘1’ along the real axis to ‘∞’.  The other
     extends from ‘-1’ along the real axis to ‘-∞’.

 -- Function: cmath.cosh (z)

     Return the hyperbolic cosine of 'z'.

 -- Function: cmath.sinh (z)

     Return the hyperbolic sine of 'z'.

 -- Function: cmath.tanh (z)

     Return the hyperbolic tangent of 'z'.


File: python.info,  Node: Classification functions,  Next: Constants<3>,  Prev: Hyperbolic functions<2>,  Up: cmath — Mathematical functions for complex numbers

5.9.3.5 Classification functions
................................

 -- Function: cmath.isfinite (z)

     Return ‘True’ if both the real and imaginary parts of 'z' are
     finite, and ‘False’ otherwise.

     Added in version 3.2.

 -- Function: cmath.isinf (z)

     Return ‘True’ if either the real or the imaginary part of 'z' is an
     infinity, and ‘False’ otherwise.

 -- Function: cmath.isnan (z)

     Return ‘True’ if either the real or the imaginary part of 'z' is a
     NaN, and ‘False’ otherwise.

 -- Function: cmath.isclose (a, b, *, rel_tol=1e-09, abs_tol=0.0)

     Return ‘True’ if the values 'a' and 'b' are close to each other and
     ‘False’ otherwise.

     Whether or not two values are considered close is determined
     according to given absolute and relative tolerances.  If no errors
     occur, the result will be: ‘abs(a-b) <= max(rel_tol * max(abs(a),
     abs(b)), abs_tol)’.

     'rel_tol' is the relative tolerance – it is the maximum allowed
     difference between 'a' and 'b', relative to the larger absolute
     value of 'a' or 'b'.  For example, to set a tolerance of 5%, pass
     ‘rel_tol=0.05’.  The default tolerance is ‘1e-09’, which assures
     that the two values are the same within about 9 decimal digits.
     'rel_tol' must be nonnegative and less than ‘1.0’.

     'abs_tol' is the absolute tolerance; it defaults to ‘0.0’ and it
     must be nonnegative.  When comparing ‘x’ to ‘0.0’, ‘isclose(x, 0)’
     is computed as ‘abs(x) <= rel_tol * abs(x)’, which is ‘False’ for
     any ‘x’ and rel_tol less than ‘1.0’.  So add an appropriate
     positive abs_tol argument to the call.

     The IEEE 754 special values of ‘NaN’, ‘inf’, and ‘-inf’ will be
     handled according to IEEE rules.  Specifically, ‘NaN’ is not
     considered close to any other value, including ‘NaN’.  ‘inf’ and
     ‘-inf’ are only considered close to themselves.

     Added in version 3.5.

     See also
     ........

     PEP 485(1) – A function for testing approximate equality

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0485/


File: python.info,  Node: Constants<3>,  Prev: Classification functions,  Up: cmath — Mathematical functions for complex numbers

5.9.3.6 Constants
.................

 -- Data: cmath.pi

     The mathematical constant 'π', as a float.

 -- Data: cmath.e

     The mathematical constant 'e', as a float.

 -- Data: cmath.tau

     The mathematical constant 'τ', as a float.

     Added in version 3.6.

 -- Data: cmath.inf

     Floating-point positive infinity.  Equivalent to ‘float('inf')’.

     Added in version 3.6.

 -- Data: cmath.infj

     Complex number with zero real part and positive infinity imaginary
     part.  Equivalent to ‘complex(0.0, float('inf'))’.

     Added in version 3.6.

 -- Data: cmath.nan

     A floating-point “not a number” (NaN) value.  Equivalent to
     ‘float('nan')’.  See also *note math.nan: 666.

     Added in version 3.6.

 -- Data: cmath.nanj

     Complex number with zero real part and NaN imaginary part.
     Equivalent to ‘complex(0.0, float('nan'))’.

     Added in version 3.6.

Note that the selection of functions is similar, but not identical, to
that in module *note math: 8e.  The reason for having two modules is
that some users aren’t interested in complex numbers, and perhaps don’t
even know what they are.  They would rather have ‘math.sqrt(-1)’ raise
an exception than return a complex number.  Also note that the functions
defined in ‘cmath’ always return a complex number, even if the answer
can be expressed as a real number (in which case the complex number has
an imaginary part of zero).

A note on branch cuts: They are curves along which the given function
fails to be continuous.  They are a necessary feature of many complex
functions.  It is assumed that if you need to compute with complex
functions, you will understand about branch cuts.  Consult almost any
(not too elementary) book on complex variables for enlightenment.  For
information of the proper choice of branch cuts for numerical purposes,
a good reference should be the following:

See also
........

Kahan, W: Branch cuts for complex elementary functions; or, Much ado
about nothing’s sign bit.  In Iserles, A., and Powell, M. (eds.), The
state of the art in numerical analysis.  Clarendon Press (1987)
pp165–211.


File: python.info,  Node: decimal — Decimal fixed-point and floating-point arithmetic,  Next: fractions — Rational numbers,  Prev: cmath — Mathematical functions for complex numbers,  Up: Numeric and Mathematical Modules

5.9.4 ‘decimal’ — Decimal fixed-point and floating-point arithmetic
-------------------------------------------------------------------

'Source code:' Lib/decimal.py(1)

__________________________________________________________________

The ‘decimal’ module provides support for fast correctly rounded decimal
floating-point arithmetic.  It offers several advantages over the *note
float: 2f7. datatype:

   * Decimal “is based on a floating-point model(2) which was designed
     with people in mind, and necessarily has a paramount guiding
     principle – computers must provide an arithmetic that works in the
     same way as the arithmetic that people learn at school.” – excerpt
     from the decimal arithmetic specification.

   * Decimal numbers can be represented exactly.  In contrast, numbers
     like ‘1.1’ and ‘2.2’ do not have exact representations in binary
     floating point.  End users typically would not expect ‘1.1 + 2.2’
     to display as ‘3.3000000000000003’ as it does with binary floating
     point.

   * The exactness carries over into arithmetic.  In decimal floating
     point, ‘0.1 + 0.1 + 0.1 - 0.3’ is exactly equal to zero.  In binary
     floating point, the result is ‘5.5511151231257827e-017’.  While
     near to zero, the differences prevent reliable equality testing and
     differences can accumulate.  For this reason, decimal is preferred
     in accounting applications which have strict equality invariants.

   * The decimal module incorporates a notion of significant places so
     that ‘1.30 + 1.20’ is ‘2.50’.  The trailing zero is kept to
     indicate significance.  This is the customary presentation for
     monetary applications.  For multiplication, the “schoolbook”
     approach uses all the figures in the multiplicands.  For instance,
     ‘1.3 * 1.2’ gives ‘1.56’ while ‘1.30 * 1.20’ gives ‘1.5600’.

   * Unlike hardware based binary floating point, the decimal module has
     a user alterable precision (defaulting to 28 places) which can be
     as large as needed for a given problem:

          >>> from decimal import *
          >>> getcontext().prec = 6
          >>> Decimal(1) / Decimal(7)
          Decimal('0.142857')
          >>> getcontext().prec = 28
          >>> Decimal(1) / Decimal(7)
          Decimal('0.1428571428571428571428571429')

   * Both binary and decimal floating point are implemented in terms of
     published standards.  While the built-in float type exposes only a
     modest portion of its capabilities, the decimal module exposes all
     required parts of the standard.  When needed, the programmer has
     full control over rounding and signal handling.  This includes an
     option to enforce exact arithmetic by using exceptions to block any
     inexact operations.

   * The decimal module was designed to support “without prejudice, both
     exact unrounded decimal arithmetic (sometimes called fixed-point
     arithmetic) and rounded floating-point arithmetic.” – excerpt from
     the decimal arithmetic specification.

The module design is centered around three concepts: the decimal number,
the context for arithmetic, and signals.

A decimal number is immutable.  It has a sign, coefficient digits, and
an exponent.  To preserve significance, the coefficient digits do not
truncate trailing zeros.  Decimals also include special values such as
‘Infinity’, ‘-Infinity’, and ‘NaN’.  The standard also differentiates
‘-0’ from ‘+0’.

The context for arithmetic is an environment specifying precision,
rounding rules, limits on exponents, flags indicating the results of
operations, and trap enablers which determine whether signals are
treated as exceptions.  Rounding options include *note ROUND_CEILING:
2804, *note ROUND_DOWN: 2805, *note ROUND_FLOOR: 2806, *note
ROUND_HALF_DOWN: 2807, *note ROUND_HALF_EVEN: 2808, *note ROUND_HALF_UP:
2809, *note ROUND_UP: 280a, and *note ROUND_05UP: 280b.

Signals are groups of exceptional conditions arising during the course
of computation.  Depending on the needs of the application, signals may
be ignored, considered as informational, or treated as exceptions.  The
signals in the decimal module are: *note Clamped: 280c, *note
InvalidOperation: 10ec, *note DivisionByZero: 280d, *note Inexact: 280e,
*note Rounded: 280f, *note Subnormal: 2810, *note Overflow: 2811, *note
Underflow: 2812. and *note FloatOperation: 10e1.

For each signal there is a flag and a trap enabler.  When a signal is
encountered, its flag is set to one, then, if the trap enabler is set to
one, an exception is raised.  Flags are sticky, so the user needs to
reset them before monitoring a calculation.

See also
........

   * IBM’s General Decimal Arithmetic Specification, The General Decimal
     Arithmetic Specification(3).

* Menu:

* Quick-start tutorial::
* Decimal objects::
* Context objects::
* Constants: Constants<4>.
* Rounding modes::
* Signals::
* Floating-point notes::
* Working with threads::
* Recipes::
* Decimal FAQ::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/decimal.py

   (2) https://speleotrove.com/decimal/damodel.html#refnumber

   (3) https://speleotrove.com/decimal/decarith.html


File: python.info,  Node: Quick-start tutorial,  Next: Decimal objects,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.1 Quick-start tutorial
............................

The usual start to using decimals is importing the module, viewing the
current context with *note getcontext(): 16dc. and, if necessary,
setting new values for precision, rounding, or enabled traps:

     >>> from decimal import *
     >>> getcontext()
     Context(prec=28, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
             capitals=1, clamp=0, flags=[], traps=[Overflow, DivisionByZero,
             InvalidOperation])

     >>> getcontext().prec = 7       # Set a new precision

Decimal instances can be constructed from integers, strings, floats, or
tuples.  Construction from an integer or a float performs an exact
conversion of the value of that integer or float.  Decimal numbers
include special values such as ‘NaN’ which stands for “Not a number”,
positive and negative ‘Infinity’, and ‘-0’:

     >>> getcontext().prec = 28
     >>> Decimal(10)
     Decimal('10')
     >>> Decimal('3.14')
     Decimal('3.14')
     >>> Decimal(3.14)
     Decimal('3.140000000000000124344978758017532527446746826171875')
     >>> Decimal((0, (3, 1, 4), -2))
     Decimal('3.14')
     >>> Decimal(str(2.0 ** 0.5))
     Decimal('1.4142135623730951')
     >>> Decimal(2) ** Decimal('0.5')
     Decimal('1.414213562373095048801688724')
     >>> Decimal('NaN')
     Decimal('NaN')
     >>> Decimal('-Infinity')
     Decimal('-Infinity')

If the *note FloatOperation: 10e1. signal is trapped, accidental mixing
of decimals and floats in constructors or ordering comparisons raises an
exception:

     >>> c = getcontext()
     >>> c.traps[FloatOperation] = True
     >>> Decimal(3.14)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     decimal.FloatOperation: [<class 'decimal.FloatOperation'>]
     >>> Decimal('3.5') < 3.7
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     decimal.FloatOperation: [<class 'decimal.FloatOperation'>]
     >>> Decimal('3.5') == 3.5
     True

Added in version 3.3.

The significance of a new Decimal is determined solely by the number of
digits input.  Context precision and rounding only come into play during
arithmetic operations.

     >>> getcontext().prec = 6
     >>> Decimal('3.0')
     Decimal('3.0')
     >>> Decimal('3.1415926535')
     Decimal('3.1415926535')
     >>> Decimal('3.1415926535') + Decimal('2.7182818285')
     Decimal('5.85987')
     >>> getcontext().rounding = ROUND_UP
     >>> Decimal('3.1415926535') + Decimal('2.7182818285')
     Decimal('5.85988')

If the internal limits of the C version are exceeded, constructing a
decimal raises *note InvalidOperation: 10ec.:

     >>> Decimal("1e9999999999999999999")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

Changed in version 3.3.

Decimals interact well with much of the rest of Python.  Here is a small
decimal floating-point flying circus:

     >>> data = list(map(Decimal, '1.34 1.87 3.45 2.35 1.00 0.03 9.25'.split()))
     >>> max(data)
     Decimal('9.25')
     >>> min(data)
     Decimal('0.03')
     >>> sorted(data)
     [Decimal('0.03'), Decimal('1.00'), Decimal('1.34'), Decimal('1.87'),
      Decimal('2.35'), Decimal('3.45'), Decimal('9.25')]
     >>> sum(data)
     Decimal('19.29')
     >>> a,b,c = data[:3]
     >>> str(a)
     '1.34'
     >>> float(a)
     1.34
     >>> round(a, 1)
     Decimal('1.3')
     >>> int(a)
     1
     >>> a * 5
     Decimal('6.70')
     >>> a * b
     Decimal('2.5058')
     >>> c % a
     Decimal('0.77')

Decimals can be formatted (with *note format(): 622. built-in or *note
f-strings: 9b4.) in fixed-point or scientific notation, using the same
formatting syntax (see *note Format specification mini-language: 1e8.)
as builtin *note float: 2f7. type:

     >>> format(Decimal('2.675'), "f")
     '2.675'
     >>> format(Decimal('2.675'), ".2f")
     '2.68'
     >>> f"{Decimal('2.675'):.2f}"
     '2.68'
     >>> format(Decimal('2.675'), ".2e")
     '2.68e+0'
     >>> with localcontext() as ctx:
     ...     ctx.rounding = ROUND_DOWN
     ...     print(format(Decimal('2.675'), ".2f"))
     ...
     2.67

And some mathematical functions are also available to Decimal:

     >>> getcontext().prec = 28
     >>> Decimal(2).sqrt()
     Decimal('1.414213562373095048801688724')
     >>> Decimal(1).exp()
     Decimal('2.718281828459045235360287471')
     >>> Decimal('10').ln()
     Decimal('2.302585092994045684017991455')
     >>> Decimal('10').log10()
     Decimal('1')

The *note quantize(): 10f4. method rounds a number to a fixed exponent.
This method is useful for monetary applications that often round results
to a fixed number of places:

     >>> Decimal('7.325').quantize(Decimal('.01'), rounding=ROUND_DOWN)
     Decimal('7.32')
     >>> Decimal('7.325').quantize(Decimal('1.'), rounding=ROUND_UP)
     Decimal('8')

As shown above, the *note getcontext(): 16dc. function accesses the
current context and allows the settings to be changed.  This approach
meets the needs of most applications.

For more advanced work, it may be useful to create alternate contexts
using the *note Context(): 10f3. constructor.  To make an alternate
active, use the *note setcontext(): 2815. function.

In accordance with the standard, the ‘decimal’ module provides two ready
to use standard contexts, *note BasicContext: 10e8. and *note
ExtendedContext: 10e9.  The former is especially useful for debugging
because many of the traps are enabled:

     >>> myothercontext = Context(prec=60, rounding=ROUND_HALF_DOWN)
     >>> setcontext(myothercontext)
     >>> Decimal(1) / Decimal(7)
     Decimal('0.142857142857142857142857142857142857142857142857142857142857')

     >>> ExtendedContext
     Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
             capitals=1, clamp=0, flags=[], traps=[])
     >>> setcontext(ExtendedContext)
     >>> Decimal(1) / Decimal(7)
     Decimal('0.142857143')
     >>> Decimal(42) / Decimal(0)
     Decimal('Infinity')

     >>> setcontext(BasicContext)
     >>> Decimal(42) / Decimal(0)
     Traceback (most recent call last):
       File "<pyshell#143>", line 1, in -toplevel-
         Decimal(42) / Decimal(0)
     DivisionByZero: x / 0

Contexts also have signal flags for monitoring exceptional conditions
encountered during computations.  The flags remain set until explicitly
cleared, so it is best to clear the flags before each set of monitored
computations by using the *note clear_flags(): 2816. method.

     >>> setcontext(ExtendedContext)
     >>> getcontext().clear_flags()
     >>> Decimal(355) / Decimal(113)
     Decimal('3.14159292')
     >>> getcontext()
     Context(prec=9, rounding=ROUND_HALF_EVEN, Emin=-999999, Emax=999999,
             capitals=1, clamp=0, flags=[Inexact, Rounded], traps=[])

The 'flags' entry shows that the rational approximation to pi was
rounded (digits beyond the context precision were thrown away) and that
the result is inexact (some of the discarded digits were non-zero).

Individual traps are set using the dictionary in the *note traps: 10f2.
attribute of a context:

     >>> setcontext(ExtendedContext)
     >>> Decimal(1) / Decimal(0)
     Decimal('Infinity')
     >>> getcontext().traps[DivisionByZero] = 1
     >>> Decimal(1) / Decimal(0)
     Traceback (most recent call last):
       File "<pyshell#112>", line 1, in -toplevel-
         Decimal(1) / Decimal(0)
     DivisionByZero: x / 0

Most programs adjust the current context only once, at the beginning of
the program.  And, in many applications, data is converted to *note
Decimal: 29d. with a single cast inside a loop.  With context set and
decimals created, the bulk of the program manipulates the data no
differently than with other Python numeric types.


File: python.info,  Node: Decimal objects,  Next: Context objects,  Prev: Quick-start tutorial,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.2 Decimal objects
.......................

 -- Class: decimal.Decimal (value='0', context=None)

     Construct a new ‘Decimal’ object based from 'value'.

     'value' can be an integer, string, tuple, *note float: 2f7, or
     another ‘Decimal’ object.  If no 'value' is given, returns
     ‘Decimal('0')’.  If 'value' is a string, it should conform to the
     decimal numeric string syntax after leading and trailing whitespace
     characters, as well as underscores throughout, are removed:

          sign           ::=  '+' | '-'
          digit          ::=  '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'
          indicator      ::=  'e' | 'E'
          digits         ::=  digit [digit]...
          decimal-part   ::=  digits '.' [digits] | ['.'] digits
          exponent-part  ::=  indicator [sign] digits
          infinity       ::=  'Infinity' | 'Inf'
          nan            ::=  'NaN' [digits] | 'sNaN' [digits]
          numeric-value  ::=  decimal-part [exponent-part] | infinity
          numeric-string ::=  [sign] numeric-value | [sign] nan

     Other Unicode decimal digits are also permitted where ‘digit’
     appears above.  These include decimal digits from various other
     alphabets (for example, Arabic-Indic and Devanāgarī digits) along
     with the fullwidth digits ‘'\uff10'’ through ‘'\uff19'’.  Case is
     not significant, so, for example, ‘inf’, ‘Inf’, ‘INFINITY’, and
     ‘iNfINity’ are all acceptable spellings for positive infinity.

     If 'value' is a *note tuple: 373, it should have three components,
     a sign (‘0’ for positive or ‘1’ for negative), a ‘tuple’ of digits,
     and an integer exponent.  For example, ‘Decimal((0, (1, 4, 1, 4),
     -3))’ returns ‘Decimal('1.414')’.

     If 'value' is a *note float: 2f7, the binary floating-point value
     is losslessly converted to its exact decimal equivalent.  This
     conversion can often require 53 or more digits of precision.  For
     example, ‘Decimal(float('1.1'))’ converts to
     ‘Decimal('1.100000000000000088817841970012523233890533447265625')’.

     The 'context' precision does not affect how many digits are stored.
     That is determined exclusively by the number of digits in 'value'.
     For example, ‘Decimal('3.00000')’ records all five zeros even if
     the context precision is only three.

     The purpose of the 'context' argument is determining what to do if
     'value' is a malformed string.  If the context traps *note
     InvalidOperation: 10ec, an exception is raised; otherwise, the
     constructor returns a new Decimal with the value of ‘NaN’.

     Once constructed, ‘Decimal’ objects are immutable.

     Changed in version 3.2: The argument to the constructor is now
     permitted to be a *note float: 2f7. instance.

     Changed in version 3.3: *note float: 2f7. arguments raise an
     exception if the *note FloatOperation: 10e1. trap is set.  By
     default the trap is off.

     Changed in version 3.6: Underscores are allowed for grouping, as
     with integral and floating-point literals in code.

     Decimal floating-point objects share many properties with the other
     built-in numeric types such as *note float: 2f7. and *note int:
     257.  All of the usual math operations and special methods apply.
     Likewise, decimal objects can be copied, pickled, printed, used as
     dictionary keys, used as set elements, compared, sorted, and
     coerced to another type (such as ‘float’ or ‘int’).

     There are some small differences between arithmetic on Decimal
     objects and arithmetic on integers and floats.  When the remainder
     operator ‘%’ is applied to Decimal objects, the sign of the result
     is the sign of the 'dividend' rather than the sign of the divisor:

          >>> (-7) % 4
          1
          >>> Decimal(-7) % Decimal(4)
          Decimal('-3')

     The integer division operator ‘//’ behaves analogously, returning
     the integer part of the true quotient (truncating towards zero)
     rather than its floor, so as to preserve the usual identity ‘x ==
     (x // y) * y + x % y’:

          >>> -7 // 4
          -2
          >>> Decimal(-7) // Decimal(4)
          Decimal('-1')

     The ‘%’ and ‘//’ operators implement the ‘remainder’ and
     ‘divide-integer’ operations (respectively) as described in the
     specification.

     Decimal objects cannot generally be combined with floats or
     instances of *note fractions.Fraction: 1e7. in arithmetic
     operations: an attempt to add a ‘Decimal’ to a *note float: 2f7,
     for example, will raise a *note TypeError: 2c3.  However, it is
     possible to use Python’s comparison operators to compare a
     ‘Decimal’ instance ‘x’ with another number ‘y’.  This avoids
     confusing results when doing equality comparisons between numbers
     of different types.

     Changed in version 3.2: Mixed-type comparisons between ‘Decimal’
     instances and other numeric types are now fully supported.

     In addition to the standard numeric properties, decimal
     floating-point objects also have a number of specialized methods:

      -- Method: adjusted ()

          Return the adjusted exponent after shifting out the
          coefficient’s rightmost digits until only the lead digit
          remains: ‘Decimal('321e+5').adjusted()’ returns seven.  Used
          for determining the position of the most significant digit
          with respect to the decimal point.

      -- Method: as_integer_ratio ()

          Return a pair ‘(n, d)’ of integers that represent the given
          ‘Decimal’ instance as a fraction, in lowest terms and with a
          positive denominator:

               >>> Decimal('-3.14').as_integer_ratio()
               (-157, 50)

          The conversion is exact.  Raise OverflowError on infinities
          and ValueError on NaNs.

     Added in version 3.6.

      -- Method: as_tuple ()

          Return a *note named tuple: 651. representation of the number:
          ‘DecimalTuple(sign, digits, exponent)’.

      -- Method: canonical ()

          Return the canonical encoding of the argument.  Currently, the
          encoding of a ‘Decimal’ instance is always canonical, so this
          operation returns its argument unchanged.

      -- Method: compare (other, context=None)

          Compare the values of two Decimal instances.  ‘compare()’
          returns a Decimal instance, and if either operand is a NaN
          then the result is a NaN:

               a or b is a NaN  ==> Decimal('NaN')
               a < b            ==> Decimal('-1')
               a == b           ==> Decimal('0')
               a > b            ==> Decimal('1')

      -- Method: compare_signal (other, context=None)

          This operation is identical to the *note compare(): 281c.
          method, except that all NaNs signal.  That is, if neither
          operand is a signaling NaN then any quiet NaN operand is
          treated as though it were a signaling NaN.

      -- Method: compare_total (other, context=None)

          Compare two operands using their abstract representation
          rather than their numerical value.  Similar to the *note
          compare(): 281c. method, but the result gives a total ordering
          on ‘Decimal’ instances.  Two ‘Decimal’ instances with the same
          numeric value but different representations compare unequal in
          this ordering:

               >>> Decimal('12.0').compare_total(Decimal('12'))
               Decimal('-1')

          Quiet and signaling NaNs are also included in the total
          ordering.  The result of this function is ‘Decimal('0')’ if
          both operands have the same representation, ‘Decimal('-1')’ if
          the first operand is lower in the total order than the second,
          and ‘Decimal('1')’ if the first operand is higher in the total
          order than the second operand.  See the specification for
          details of the total order.

          This operation is unaffected by context and is quiet: no flags
          are changed and no rounding is performed.  As an exception,
          the C version may raise InvalidOperation if the second operand
          cannot be converted exactly.

      -- Method: compare_total_mag (other, context=None)

          Compare two operands using their abstract representation
          rather than their value as in *note compare_total(): 281e, but
          ignoring the sign of each operand.  ‘x.compare_total_mag(y)’
          is equivalent to ‘x.copy_abs().compare_total(y.copy_abs())’.

          This operation is unaffected by context and is quiet: no flags
          are changed and no rounding is performed.  As an exception,
          the C version may raise InvalidOperation if the second operand
          cannot be converted exactly.

      -- Method: conjugate ()

          Just returns self, this method is only to comply with the
          Decimal Specification.

      -- Method: copy_abs ()

          Return the absolute value of the argument.  This operation is
          unaffected by the context and is quiet: no flags are changed
          and no rounding is performed.

      -- Method: copy_negate ()

          Return the negation of the argument.  This operation is
          unaffected by the context and is quiet: no flags are changed
          and no rounding is performed.

      -- Method: copy_sign (other, context=None)

          Return a copy of the first operand with the sign set to be the
          same as the sign of the second operand.  For example:

               >>> Decimal('2.3').copy_sign(Decimal('-1.5'))
               Decimal('-2.3')

          This operation is unaffected by context and is quiet: no flags
          are changed and no rounding is performed.  As an exception,
          the C version may raise InvalidOperation if the second operand
          cannot be converted exactly.

      -- Method: exp (context=None)

          Return the value of the (natural) exponential function ‘e**x’
          at the given number.  The result is correctly rounded using
          the *note ROUND_HALF_EVEN: 2808. rounding mode.

               >>> Decimal(1).exp()
               Decimal('2.718281828459045235360287471')
               >>> Decimal(321).exp()
               Decimal('2.561702493119680037517373933E+139')

      -- Method: classmethod from_float (f, /)

          Alternative constructor that only accepts instances of *note
          float: 2f7. or *note int: 257.

          Note ‘Decimal.from_float(0.1)’ is not the same as
          ‘Decimal('0.1')’.  Since 0.1 is not exactly representable in
          binary floating point, the value is stored as the nearest
          representable value which is ‘0x1.999999999999ap-4’.  That
          equivalent value in decimal is
          ‘0.1000000000000000055511151231257827021181583404541015625’.

               Note: From Python 3.2 onwards, a ‘Decimal’ instance can
               also be constructed directly from a *note float: 2f7.

               >>> Decimal.from_float(0.1)
               Decimal('0.1000000000000000055511151231257827021181583404541015625')
               >>> Decimal.from_float(float('nan'))
               Decimal('NaN')
               >>> Decimal.from_float(float('inf'))
               Decimal('Infinity')
               >>> Decimal.from_float(float('-inf'))
               Decimal('-Infinity')

          Added in version 3.1.

      -- Method: fma (other, third, context=None)

          Fused multiply-add.  Return self*other+third with no rounding
          of the intermediate product self*other.

               >>> Decimal(2).fma(3, 5)
               Decimal('11')

      -- Method: is_canonical ()

          Return *note True: c2d. if the argument is canonical and *note
          False: b4f. otherwise.  Currently, a ‘Decimal’ instance is
          always canonical, so this operation always returns ‘True’.

      -- Method: is_finite ()

          Return *note True: c2d. if the argument is a finite number,
          and *note False: b4f. if the argument is an infinity or a NaN.

      -- Method: is_infinite ()

          Return *note True: c2d. if the argument is either positive or
          negative infinity and *note False: b4f. otherwise.

      -- Method: is_nan ()

          Return *note True: c2d. if the argument is a (quiet or
          signaling) NaN and *note False: b4f. otherwise.

      -- Method: is_normal (context=None)

          Return *note True: c2d. if the argument is a 'normal' finite
          number.  Return *note False: b4f. if the argument is zero,
          subnormal, infinite or a NaN.

      -- Method: is_qnan ()

          Return *note True: c2d. if the argument is a quiet NaN, and
          *note False: b4f. otherwise.

      -- Method: is_signed ()

          Return *note True: c2d. if the argument has a negative sign
          and *note False: b4f. otherwise.  Note that zeros and NaNs can
          both carry signs.

      -- Method: is_snan ()

          Return *note True: c2d. if the argument is a signaling NaN and
          *note False: b4f. otherwise.

      -- Method: is_subnormal (context=None)

          Return *note True: c2d. if the argument is subnormal, and
          *note False: b4f. otherwise.

      -- Method: is_zero ()

          Return *note True: c2d. if the argument is a (positive or
          negative) zero and *note False: b4f. otherwise.

      -- Method: ln (context=None)

          Return the natural (base e) logarithm of the operand.  The
          result is correctly rounded using the *note ROUND_HALF_EVEN:
          2808. rounding mode.

      -- Method: log10 (context=None)

          Return the base ten logarithm of the operand.  The result is
          correctly rounded using the *note ROUND_HALF_EVEN: 2808.
          rounding mode.

      -- Method: logb (context=None)

          For a nonzero number, return the adjusted exponent of its
          operand as a ‘Decimal’ instance.  If the operand is a zero
          then ‘Decimal('-Infinity')’ is returned and the *note
          DivisionByZero: 280d. flag is raised.  If the operand is an
          infinity then ‘Decimal('Infinity')’ is returned.

      -- Method: logical_and (other, context=None)

          ‘logical_and()’ is a logical operation which takes two
          'logical operands' (see *note Logical operands: 2832.).  The
          result is the digit-wise ‘and’ of the two operands.

      -- Method: logical_invert (context=None)

          ‘logical_invert()’ is a logical operation.  The result is the
          digit-wise inversion of the operand.

      -- Method: logical_or (other, context=None)

          ‘logical_or()’ is a logical operation which takes two 'logical
          operands' (see *note Logical operands: 2832.).  The result is
          the digit-wise ‘or’ of the two operands.

      -- Method: logical_xor (other, context=None)

          ‘logical_xor()’ is a logical operation which takes two
          'logical operands' (see *note Logical operands: 2832.).  The
          result is the digit-wise exclusive or of the two operands.

      -- Method: max (other, context=None)

          Like ‘max(self, other)’ except that the context rounding rule
          is applied before returning and that ‘NaN’ values are either
          signaled or ignored (depending on the context and whether they
          are signaling or quiet).

      -- Method: max_mag (other, context=None)

          Similar to the *note max(): 2836. method, but the comparison
          is done using the absolute values of the operands.

      -- Method: min (other, context=None)

          Like ‘min(self, other)’ except that the context rounding rule
          is applied before returning and that ‘NaN’ values are either
          signaled or ignored (depending on the context and whether they
          are signaling or quiet).

      -- Method: min_mag (other, context=None)

          Similar to the *note min(): 2838. method, but the comparison
          is done using the absolute values of the operands.

      -- Method: next_minus (context=None)

          Return the largest number representable in the given context
          (or in the current thread’s context if no context is given)
          that is smaller than the given operand.

      -- Method: next_plus (context=None)

          Return the smallest number representable in the given context
          (or in the current thread’s context if no context is given)
          that is larger than the given operand.

      -- Method: next_toward (other, context=None)

          If the two operands are unequal, return the number closest to
          the first operand in the direction of the second operand.  If
          both operands are numerically equal, return a copy of the
          first operand with the sign set to be the same as the sign of
          the second operand.

      -- Method: normalize (context=None)

          Used for producing canonical values of an equivalence class
          within either the current context or the specified context.

          This has the same semantics as the unary plus operation,
          except that if the final result is finite it is reduced to its
          simplest form, with all trailing zeros removed and its sign
          preserved.  That is, while the coefficient is non-zero and a
          multiple of ten the coefficient is divided by ten and the
          exponent is incremented by 1.  Otherwise (the coefficient is
          zero) the exponent is set to 0.  In all cases the sign is
          unchanged.

          For example, ‘Decimal('32.100')’ and ‘Decimal('0.321000e+2')’
          both normalize to the equivalent value ‘Decimal('32.1')’.

          Note that rounding is applied 'before' reducing to simplest
          form.

          In the latest versions of the specification, this operation is
          also known as ‘reduce’.

      -- Method: number_class (context=None)

          Return a string describing the 'class' of the operand.  The
          returned value is one of the following ten strings.

             * ‘"-Infinity"’, indicating that the operand is negative
               infinity.

             * ‘"-Normal"’, indicating that the operand is a negative
               normal number.

             * ‘"-Subnormal"’, indicating that the operand is negative
               and subnormal.

             * ‘"-Zero"’, indicating that the operand is a negative
               zero.

             * ‘"+Zero"’, indicating that the operand is a positive
               zero.

             * ‘"+Subnormal"’, indicating that the operand is positive
               and subnormal.

             * ‘"+Normal"’, indicating that the operand is a positive
               normal number.

             * ‘"+Infinity"’, indicating that the operand is positive
               infinity.

             * ‘"NaN"’, indicating that the operand is a quiet NaN (Not
               a Number).

             * ‘"sNaN"’, indicating that the operand is a signaling NaN.

      -- Method: quantize (exp, rounding=None, context=None)

          Return a value equal to the first operand after rounding and
          having the exponent of the second operand.

               >>> Decimal('1.41421356').quantize(Decimal('1.000'))
               Decimal('1.414')

          Unlike other operations, if the length of the coefficient
          after the quantize operation would be greater than precision,
          then an *note InvalidOperation: 10ec. is signaled.  This
          guarantees that, unless there is an error condition, the
          quantized exponent is always equal to that of the right-hand
          operand.

          Also unlike other operations, quantize never signals
          Underflow, even if the result is subnormal and inexact.

          If the exponent of the second operand is larger than that of
          the first then rounding may be necessary.  In this case, the
          rounding mode is determined by the ‘rounding’ argument if
          given, else by the given ‘context’ argument; if neither
          argument is given the rounding mode of the current thread’s
          context is used.

          An error is returned whenever the resulting exponent is
          greater than *note Emax: 10ea. or less than *note Etiny():
          283f.

      -- Method: radix ()

          Return ‘Decimal(10)’, the radix (base) in which the ‘Decimal’
          class does all its arithmetic.  Included for compatibility
          with the specification.

      -- Method: remainder_near (other, context=None)

          Return the remainder from dividing 'self' by 'other'.  This
          differs from ‘self % other’ in that the sign of the remainder
          is chosen so as to minimize its absolute value.  More
          precisely, the return value is ‘self - n * other’ where ‘n’ is
          the integer nearest to the exact value of ‘self / other’, and
          if two integers are equally near then the even one is chosen.

          If the result is zero then its sign will be the sign of
          'self'.

               >>> Decimal(18).remainder_near(Decimal(10))
               Decimal('-2')
               >>> Decimal(25).remainder_near(Decimal(10))
               Decimal('5')
               >>> Decimal(35).remainder_near(Decimal(10))
               Decimal('-5')

      -- Method: rotate (other, context=None)

          Return the result of rotating the digits of the first operand
          by an amount specified by the second operand.  The second
          operand must be an integer in the range -precision through
          precision.  The absolute value of the second operand gives the
          number of places to rotate.  If the second operand is positive
          then rotation is to the left; otherwise rotation is to the
          right.  The coefficient of the first operand is padded on the
          left with zeros to length precision if necessary.  The sign
          and exponent of the first operand are unchanged.

      -- Method: same_quantum (other, context=None)

          Test whether self and other have the same exponent or whether
          both are ‘NaN’.

          This operation is unaffected by context and is quiet: no flags
          are changed and no rounding is performed.  As an exception,
          the C version may raise InvalidOperation if the second operand
          cannot be converted exactly.

      -- Method: scaleb (other, context=None)

          Return the first operand with exponent adjusted by the second.
          Equivalently, return the first operand multiplied by
          ‘10**other’.  The second operand must be an integer.

      -- Method: shift (other, context=None)

          Return the result of shifting the digits of the first operand
          by an amount specified by the second operand.  The second
          operand must be an integer in the range -precision through
          precision.  The absolute value of the second operand gives the
          number of places to shift.  If the second operand is positive
          then the shift is to the left; otherwise the shift is to the
          right.  Digits shifted into the coefficient are zeros.  The
          sign and exponent of the first operand are unchanged.

      -- Method: sqrt (context=None)

          Return the square root of the argument to full precision.

      -- Method: to_eng_string (context=None)

          Convert to a string, using engineering notation if an exponent
          is needed.

          Engineering notation has an exponent which is a multiple of 3.
          This can leave up to 3 digits to the left of the decimal place
          and may require the addition of either one or two trailing
          zeros.

          For example, this converts ‘Decimal('123E+1')’ to
          ‘Decimal('1.23E+3')’.

      -- Method: to_integral (rounding=None, context=None)

          Identical to the *note to_integral_value(): 2849. method.  The
          ‘to_integral’ name has been kept for compatibility with older
          versions.

      -- Method: to_integral_exact (rounding=None, context=None)

          Round to the nearest integer, signaling *note Inexact: 280e.
          or *note Rounded: 280f. as appropriate if rounding occurs.
          The rounding mode is determined by the ‘rounding’ parameter if
          given, else by the given ‘context’.  If neither parameter is
          given then the rounding mode of the current context is used.

      -- Method: to_integral_value (rounding=None, context=None)

          Round to the nearest integer without signaling *note Inexact:
          280e. or *note Rounded: 280f.  If given, applies 'rounding';
          otherwise, uses the rounding method in either the supplied
          'context' or the current context.

     Decimal numbers can be rounded using the *note round(): 1322.
     function:

      -- Describe: round(number)

      -- Describe: round(number, ndigits)

          If 'ndigits' is not given or ‘None’, returns the nearest *note
          int: 257. to 'number', rounding ties to even, and ignoring the
          rounding mode of the ‘Decimal’ context.  Raises *note
          OverflowError: 888. if 'number' is an infinity or *note
          ValueError: 202. if it is a (quiet or signaling) NaN.

          If 'ndigits' is an *note int: 257, the context’s rounding mode
          is respected and a ‘Decimal’ representing 'number' rounded to
          the nearest multiple of ‘Decimal('1E-ndigits')’ is returned;
          in this case, ‘round(number, ndigits)’ is equivalent to
          ‘self.quantize(Decimal('1E-ndigits'))’.  Returns
          ‘Decimal('NaN')’ if 'number' is a quiet NaN. Raises *note
          InvalidOperation: 10ec. if 'number' is an infinity, a
          signaling NaN, or if the length of the coefficient after the
          quantize operation would be greater than the current context’s
          precision.  In other words, for the non-corner cases:

             * if 'ndigits' is positive, return 'number' rounded to
               'ndigits' decimal places;

             * if 'ndigits' is zero, return 'number' rounded to the
               nearest integer;

             * if 'ndigits' is negative, return 'number' rounded to the
               nearest multiple of ‘10**abs(ndigits)’.

          For example:

               >>> from decimal import Decimal, getcontext, ROUND_DOWN
               >>> getcontext().rounding = ROUND_DOWN
               >>> round(Decimal('3.75'))     # context rounding ignored
               4
               >>> round(Decimal('3.5'))      # round-ties-to-even
               4
               >>> round(Decimal('3.75'), 0)  # uses the context rounding
               Decimal('3')
               >>> round(Decimal('3.75'), 1)
               Decimal('3.7')
               >>> round(Decimal('3.75'), -1)
               Decimal('0E+1')

* Menu:

* Logical operands::


File: python.info,  Node: Logical operands,  Up: Decimal objects

5.9.4.3 Logical operands
........................

The *note logical_and(): 2831, *note logical_invert(): 2833, *note
logical_or(): 2834, and *note logical_xor(): 2835. methods expect their
arguments to be 'logical operands'.  A 'logical operand' is a *note
Decimal: 29d. instance whose exponent and sign are both zero, and whose
digits are all either ‘0’ or ‘1’.


File: python.info,  Node: Context objects,  Next: Constants<4>,  Prev: Decimal objects,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.4 Context objects
.......................

Contexts are environments for arithmetic operations.  They govern
precision, set rules for rounding, determine which signals are treated
as exceptions, and limit the range for exponents.

Each thread has its own current context which is accessed or changed
using the *note getcontext(): 16dc. and *note setcontext(): 2815.
functions:

 -- Function: decimal.getcontext ()

     Return the current context for the active thread.

 -- Function: decimal.setcontext (c, /)

     Set the current context for the active thread to 'c'.

You can also use the *note with: 5d5. statement and the *note
localcontext(): 13d3. function to temporarily change the active context.

 -- Function: decimal.localcontext (ctx=None, **kwargs)

     Return a context manager that will set the current context for the
     active thread to a copy of 'ctx' on entry to the with-statement and
     restore the previous context when exiting the with-statement.  If
     no context is specified, a copy of the current context is used.
     The 'kwargs' argument is used to set the attributes of the new
     context.

     For example, the following code sets the current decimal precision
     to 42 places, performs a calculation, and then automatically
     restores the previous context:

          from decimal import localcontext

          with localcontext() as ctx:
              ctx.prec = 42   # Perform a high precision calculation
              s = calculate_something()
          s = +s  # Round the final result back to the default precision

     Using keyword arguments, the code would be the following:

          from decimal import localcontext

          with localcontext(prec=42) as ctx:
              s = calculate_something()
          s = +s

     Raises *note TypeError: 2c3. if 'kwargs' supplies an attribute that
     *note Context: 10f3. doesn’t support.  Raises either ‘TypeError’ or
     *note ValueError: 202. if 'kwargs' supplies an invalid value for an
     attribute.

     Changed in version 3.11: *note localcontext(): 13d3. now supports
     setting context attributes through the use of keyword arguments.

New contexts can also be created using the *note Context: 10f3.
constructor described below.  In addition, the module provides three
pre-made contexts:

 -- Data: decimal.BasicContext

     This is a standard context defined by the General Decimal
     Arithmetic Specification.  Precision is set to nine.  Rounding is
     set to *note ROUND_HALF_UP: 2809.  All flags are cleared.  All
     traps are enabled (treated as exceptions) except *note Inexact:
     280e, *note Rounded: 280f, and *note Subnormal: 2810.

     Because many of the traps are enabled, this context is useful for
     debugging.

 -- Data: decimal.ExtendedContext

     This is a standard context defined by the General Decimal
     Arithmetic Specification.  Precision is set to nine.  Rounding is
     set to *note ROUND_HALF_EVEN: 2808.  All flags are cleared.  No
     traps are enabled (so that exceptions are not raised during
     computations).

     Because the traps are disabled, this context is useful for
     applications that prefer to have result value of ‘NaN’ or
     ‘Infinity’ instead of raising exceptions.  This allows an
     application to complete a run in the presence of conditions that
     would otherwise halt the program.

 -- Data: decimal.DefaultContext

     This context is used by the *note Context: 10f3. constructor as a
     prototype for new contexts.  Changing a field (such a precision)
     has the effect of changing the default for new contexts created by
     the ‘Context’ constructor.

     This context is most useful in multi-threaded environments.
     Changing one of the fields before threads are started has the
     effect of setting system-wide defaults.  Changing the fields after
     threads have started is not recommended as it would require thread
     synchronization to prevent race conditions.

     In single threaded environments, it is preferable to not use this
     context at all.  Instead, simply create contexts explicitly as
     described below.

     The default values are *note Context.prec: 284d.=‘28’, *note
     Context.rounding: 284e.=*note ROUND_HALF_EVEN: 2808, and enabled
     traps for *note Overflow: 2811, *note InvalidOperation: 10ec, and
     *note DivisionByZero: 280d.

In addition to the three supplied contexts, new contexts can be created
with the *note Context: 10f3. constructor.

 -- Class: decimal.Context (prec=None, rounding=None, Emin=None,
          Emax=None, capitals=None, clamp=None, flags=None, traps=None)

     Creates a new context.  If a field is not specified or is *note
     None: 678, the default values are copied from the *note
     DefaultContext: 10e7.  If the 'flags' field is not specified or is
     ‘None’, all flags are cleared.

      -- Attribute: prec

          An integer in the range [‘1’, *note MAX_PREC: 10e4.] that sets
          the precision for arithmetic operations in the context.

      -- Attribute: rounding

          One of the constants listed in the section *note Rounding
          Modes: 284f.

      -- Attribute: traps
      -- Attribute: flags

          Lists of any signals to be set.  Generally, new contexts
          should only set traps and leave the flags clear.

      -- Attribute: Emin
      -- Attribute: Emax

          Integers specifying the outer limits allowable for exponents.
          'Emin' must be in the range [*note MIN_EMIN: 10e6, ‘0’],
          'Emax' in the range [‘0’, *note MAX_EMAX: 10e5.].

      -- Attribute: capitals

          Either ‘0’ or ‘1’ (the default).  If set to ‘1’, exponents are
          printed with a capital ‘E’; otherwise, a lowercase ‘e’ is
          used: ‘Decimal('6.02e+23')’.

      -- Attribute: clamp

          Either ‘0’ (the default) or ‘1’.  If set to ‘1’, the exponent
          ‘e’ of a *note Decimal: 29d. instance representable in this
          context is strictly limited to the range ‘Emin - prec + 1 <= e
          <= Emax - prec + 1’.  If 'clamp' is ‘0’ then a weaker
          condition holds: the adjusted exponent of the ‘Decimal’
          instance is at most *note Emax: 10ea.  When 'clamp' is ‘1’, a
          large normal number will, where possible, have its exponent
          reduced and a corresponding number of zeros added to its
          coefficient, in order to fit the exponent constraints; this
          preserves the value of the number but loses information about
          significant trailing zeros.  For example:

               >>> Context(prec=6, Emax=999, clamp=1).create_decimal('1.23e999')
               Decimal('1.23000E+999')

          A 'clamp' value of ‘1’ allows compatibility with the
          fixed-width decimal interchange formats specified in IEEE 754.

     The ‘Context’ class defines several general purpose methods as well
     as a large number of methods for doing arithmetic directly in a
     given context.  In addition, for each of the *note Decimal: 29d.
     methods described above (with the exception of the *note
     adjusted(): 2819. and *note as_tuple(): 281a. methods) there is a
     corresponding ‘Context’ method.  For example, for a ‘Context’
     instance ‘C’ and ‘Decimal’ instance ‘x’, ‘C.exp(x)’ is equivalent
     to ‘x.exp(context=C)’.  Each ‘Context’ method accepts a Python
     integer (an instance of *note int: 257.) anywhere that a Decimal
     instance is accepted.

      -- Method: clear_flags ()

          Resets all of the flags to ‘0’.

      -- Method: clear_traps ()

          Resets all of the traps to ‘0’.

          Added in version 3.3.

      -- Method: copy ()

          Return a duplicate of the context.

      -- Method: copy_decimal (num, /)

          Return a copy of the Decimal instance num.

      -- Method: create_decimal (num='0', /)

          Creates a new Decimal instance from 'num' but using 'self' as
          context.  Unlike the *note Decimal: 29d. constructor, the
          context precision, rounding method, flags, and traps are
          applied to the conversion.

          This is useful because constants are often given to a greater
          precision than is needed by the application.  Another benefit
          is that rounding immediately eliminates unintended effects
          from digits beyond the current precision.  In the following
          example, using unrounded inputs means that adding zero to a
          sum can change the result:

               >>> getcontext().prec = 3
               >>> Decimal('3.4445') + Decimal('1.0023')
               Decimal('4.45')
               >>> Decimal('3.4445') + Decimal(0) + Decimal('1.0023')
               Decimal('4.44')

          This method implements the to-number operation of the IBM
          specification.  If the argument is a string, no leading or
          trailing whitespace or underscores are permitted.

      -- Method: create_decimal_from_float (f, /)

          Creates a new Decimal instance from a float 'f' but rounding
          using 'self' as the context.  Unlike the *note
          Decimal.from_float(): 1249. class method, the context
          precision, rounding method, flags, and traps are applied to
          the conversion.

               >>> context = Context(prec=5, rounding=ROUND_DOWN)
               >>> context.create_decimal_from_float(math.pi)
               Decimal('3.1415')
               >>> context = Context(prec=5, traps=[Inexact])
               >>> context.create_decimal_from_float(math.pi)
               Traceback (most recent call last):
                   ...
               decimal.Inexact: None

          Added in version 3.1.

      -- Method: Etiny ()

          Returns a value equal to ‘Emin - prec + 1’ which is the
          minimum exponent value for subnormal results.  When underflow
          occurs, the exponent is set to *note Etiny: 283f.

      -- Method: Etop ()

          Returns a value equal to ‘Emax - prec + 1’.

     The usual approach to working with decimals is to create *note
     Decimal: 29d. instances and then apply arithmetic operations which
     take place within the current context for the active thread.  An
     alternative approach is to use context methods for calculating
     within a specific context.  The methods are similar to those for
     the ‘Decimal’ class and are only briefly recounted here.

      -- Method: abs (x, /)

          Returns the absolute value of 'x'.

      -- Method: add (x, y, /)

          Return the sum of 'x' and 'y'.

      -- Method: canonical (x, /)

          Returns the same Decimal object 'x'.

      -- Method: compare (x, y, /)

          Compares 'x' and 'y' numerically.

      -- Method: compare_signal (x, y, /)

          Compares the values of the two operands numerically.

      -- Method: compare_total (x, y, /)

          Compares two operands using their abstract representation.

      -- Method: compare_total_mag (x, y, /)

          Compares two operands using their abstract representation,
          ignoring sign.

      -- Method: copy_abs (x, /)

          Returns a copy of 'x' with the sign set to 0.

      -- Method: copy_negate (x, /)

          Returns a copy of 'x' with the sign inverted.

      -- Method: copy_sign (x, y, /)

          Copies the sign from 'y' to 'x'.

      -- Method: divide (x, y, /)

          Return 'x' divided by 'y'.

      -- Method: divide_int (x, y, /)

          Return 'x' divided by 'y', truncated to an integer.

      -- Method: divmod (x, y, /)

          Divides two numbers and returns the integer part of the
          result.

      -- Method: exp (x, /)

          Returns ‘e ** x’.

      -- Method: fma (x, y, z, /)

          Returns 'x' multiplied by 'y', plus 'z'.

      -- Method: is_canonical (x, /)

          Returns ‘True’ if 'x' is canonical; otherwise returns ‘False’.

      -- Method: is_finite (x, /)

          Returns ‘True’ if 'x' is finite; otherwise returns ‘False’.

      -- Method: is_infinite (x, /)

          Returns ‘True’ if 'x' is infinite; otherwise returns ‘False’.

      -- Method: is_nan (x, /)

          Returns ‘True’ if 'x' is a qNaN or sNaN; otherwise returns
          ‘False’.

      -- Method: is_normal (x, /)

          Returns ‘True’ if 'x' is a normal number; otherwise returns
          ‘False’.

      -- Method: is_qnan (x, /)

          Returns ‘True’ if 'x' is a quiet NaN; otherwise returns
          ‘False’.

      -- Method: is_signed (x, /)

          Returns ‘True’ if 'x' is negative; otherwise returns ‘False’.

      -- Method: is_snan (x, /)

          Returns ‘True’ if 'x' is a signaling NaN; otherwise returns
          ‘False’.

      -- Method: is_subnormal (x, /)

          Returns ‘True’ if 'x' is subnormal; otherwise returns ‘False’.

      -- Method: is_zero (x, /)

          Returns ‘True’ if 'x' is a zero; otherwise returns ‘False’.

      -- Method: ln (x, /)

          Returns the natural (base e) logarithm of 'x'.

      -- Method: log10 (x, /)

          Returns the base 10 logarithm of 'x'.

      -- Method: logb (x, /)

          Returns the exponent of the magnitude of the operand’s MSD.

      -- Method: logical_and (x, y, /)

          Applies the logical operation 'and' between each operand’s
          digits.

      -- Method: logical_invert (x, /)

          Invert all the digits in 'x'.

      -- Method: logical_or (x, y, /)

          Applies the logical operation 'or' between each operand’s
          digits.

      -- Method: logical_xor (x, y, /)

          Applies the logical operation 'xor' between each operand’s
          digits.

      -- Method: max (x, y, /)

          Compares two values numerically and returns the maximum.

      -- Method: max_mag (x, y, /)

          Compares the values numerically with their sign ignored.

      -- Method: min (x, y, /)

          Compares two values numerically and returns the minimum.

      -- Method: min_mag (x, y, /)

          Compares the values numerically with their sign ignored.

      -- Method: minus (x, /)

          Minus corresponds to the unary prefix minus operator in
          Python.

      -- Method: multiply (x, y, /)

          Return the product of 'x' and 'y'.

      -- Method: next_minus (x, /)

          Returns the largest representable number smaller than 'x'.

      -- Method: next_plus (x, /)

          Returns the smallest representable number larger than 'x'.

      -- Method: next_toward (x, y, /)

          Returns the number closest to 'x', in direction towards 'y'.

      -- Method: normalize (x, /)

          Reduces 'x' to its simplest form.

      -- Method: number_class (x, /)

          Returns an indication of the class of 'x'.

      -- Method: plus (x, /)

          Plus corresponds to the unary prefix plus operator in Python.
          This operation applies the context precision and rounding, so
          it is 'not' an identity operation.

      -- Method: power (x, y, modulo=None)

          Return ‘x’ to the power of ‘y’, reduced modulo ‘modulo’ if
          given.

          With two arguments, compute ‘x**y’.  If ‘x’ is negative then
          ‘y’ must be integral.  The result will be inexact unless ‘y’
          is integral and the result is finite and can be expressed
          exactly in ‘precision’ digits.  The rounding mode of the
          context is used.  Results are always correctly rounded in the
          Python version.

          ‘Decimal(0) ** Decimal(0)’ results in ‘InvalidOperation’, and
          if ‘InvalidOperation’ is not trapped, then results in
          ‘Decimal('NaN')’.

          Changed in version 3.3: The C module computes ‘power()’ in
          terms of the correctly rounded *note exp(): 2862. and *note
          ln(): 286d. functions.  The result is well-defined but only
          “almost always correctly rounded”.

          With three arguments, compute ‘(x**y) % modulo’.  For the
          three argument form, the following restrictions on the
          arguments hold:

             - all three arguments must be integral

             - ‘y’ must be nonnegative

             - at least one of ‘x’ or ‘y’ must be nonzero

             - ‘modulo’ must be nonzero and have at most ‘precision’
               digits

          The value resulting from ‘Context.power(x, y, modulo)’ is
          equal to the value that would be obtained by computing ‘(x**y)
          % modulo’ with unbounded precision, but is computed more
          efficiently.  The exponent of the result is zero, regardless
          of the exponents of ‘x’, ‘y’ and ‘modulo’.  The result is
          always exact.

      -- Method: quantize (x, y, /)

          Returns a value equal to 'x' (rounded), having the exponent of
          'y'.

      -- Method: radix ()

          Just returns 10, as this is Decimal, :)

      -- Method: remainder (x, y, /)

          Returns the remainder from integer division.

          The sign of the result, if non-zero, is the same as that of
          the original dividend.

      -- Method: remainder_near (x, y, /)

          Returns ‘x - y * n’, where 'n' is the integer nearest the
          exact value of ‘x / y’ (if the result is 0 then its sign will
          be the sign of 'x').

      -- Method: rotate (x, y, /)

          Returns a rotated copy of 'x', 'y' times.

      -- Method: same_quantum (x, y, /)

          Returns ‘True’ if the two operands have the same exponent.

      -- Method: scaleb (x, y, /)

          Returns the first operand after adding the second value its
          exp.

      -- Method: shift (x, y, /)

          Returns a shifted copy of 'x', 'y' times.

      -- Method: sqrt (x, /)

          Square root of a non-negative number to context precision.

      -- Method: subtract (x, y, /)

          Return the difference between 'x' and 'y'.

      -- Method: to_eng_string (x, /)

          Convert to a string, using engineering notation if an exponent
          is needed.

          Engineering notation has an exponent which is a multiple of 3.
          This can leave up to 3 digits to the left of the decimal place
          and may require the addition of either one or two trailing
          zeros.

      -- Method: to_integral_exact (x, /)

          Rounds to an integer.

      -- Method: to_sci_string (x, /)

          Converts a number to a string using scientific notation.


File: python.info,  Node: Constants<4>,  Next: Rounding modes,  Prev: Context objects,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.5 Constants
.................

The constants in this section are only relevant for the C module.  They
are also included in the pure Python version for compatibility.

                          32-bit                    64-bit
                                                    
----------------------------------------------------------------------------------------
                                                    
 -- Data:                 ‘425000000’               ‘999999999999999999’
          decimal.MAX_PREC                          

 -- Data:                 ‘425000000’               ‘999999999999999999’
          decimal.MAX_EMAX                          

 -- Data:                 ‘-425000000’              ‘-999999999999999999’
          decimal.MIN_EMIN                          

 -- Data:                 ‘-849999999’              ‘-1999999999999999997’
          decimal.MIN_ETINY                         

 -- Data: decimal.HAVE_THREADS

     The value is ‘True’.  Deprecated, because Python now always has
     threads.

     Deprecated since version 3.9.

 -- Data: decimal.HAVE_CONTEXTVAR

     The default value is ‘True’.  If Python is *note configured using
     the -without-decimal-contextvar option: 1f19, the C version uses a
     thread-local rather than a coroutine-local context and the value is
     ‘False’.  This is slightly faster in some nested context scenarios.

     Added in version 3.8.3.


File: python.info,  Node: Rounding modes,  Next: Signals,  Prev: Constants<4>,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.6 Rounding modes
......................

 -- Data: decimal.ROUND_CEILING

     Round towards ‘Infinity’.

 -- Data: decimal.ROUND_DOWN

     Round towards zero.

 -- Data: decimal.ROUND_FLOOR

     Round towards ‘-Infinity’.

 -- Data: decimal.ROUND_HALF_DOWN

     Round to nearest with ties going towards zero.

 -- Data: decimal.ROUND_HALF_EVEN

     Round to nearest with ties going to nearest even integer.

 -- Data: decimal.ROUND_HALF_UP

     Round to nearest with ties going away from zero.

 -- Data: decimal.ROUND_UP

     Round away from zero.

 -- Data: decimal.ROUND_05UP

     Round away from zero if last digit after rounding towards zero
     would have been 0 or 5; otherwise round towards zero.


File: python.info,  Node: Signals,  Next: Floating-point notes,  Prev: Rounding modes,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.7 Signals
...............

Signals represent conditions that arise during computation.  Each
corresponds to one context flag and one context trap enabler.

The context flag is set whenever the condition is encountered.  After
the computation, flags may be checked for informational purposes (for
instance, to determine whether a computation was exact).  After checking
the flags, be sure to clear all flags before starting the next
computation.

If the context’s trap enabler is set for the signal, then the condition
causes a Python exception to be raised.  For example, if the *note
DivisionByZero: 280d. trap is set, then a *note DivisionByZero: 280d.
exception is raised upon encountering the condition.

 -- Class: decimal.Clamped

     Altered an exponent to fit representation constraints.

     Typically, clamping occurs when an exponent falls outside the
     context’s *note Emin: 10eb. and *note Emax: 10ea. limits.  If
     possible, the exponent is reduced to fit by adding zeros to the
     coefficient.

 -- Class: decimal.DecimalException

     Base class for other signals and a subclass of *note
     ArithmeticError: 243d.

 -- Class: decimal.DivisionByZero

     Signals the division of a non-infinite number by zero.

     Can occur with division, modulo division, or when raising a number
     to a negative power.  If this signal is not trapped, returns
     ‘Infinity’ or ‘-Infinity’ with the sign determined by the inputs to
     the calculation.

 -- Class: decimal.Inexact

     Indicates that rounding occurred and the result is not exact.

     Signals when non-zero digits were discarded during rounding.  The
     rounded result is returned.  The signal flag or trap is used to
     detect when results are inexact.

 -- Class: decimal.InvalidOperation

     An invalid operation was performed.

     Indicates that an operation was requested that does not make sense.
     If not trapped, returns ‘NaN’.  Possible causes include:

          Infinity - Infinity
          0 * Infinity
          Infinity / Infinity
          x % 0
          Infinity % x
          sqrt(-x) and x > 0
          0 ** 0
          x ** (non-integer)
          x ** Infinity

 -- Class: decimal.Overflow

     Numerical overflow.

     Indicates the exponent is larger than *note Context.Emax: 10ea.
     after rounding has occurred.  If not trapped, the result depends on
     the rounding mode, either pulling inward to the largest
     representable finite number or rounding outward to ‘Infinity’.  In
     either case, *note Inexact: 280e. and *note Rounded: 280f. are also
     signaled.

 -- Class: decimal.Rounded

     Rounding occurred though possibly no information was lost.

     Signaled whenever rounding discards digits; even if those digits
     are zero (such as rounding ‘5.00’ to ‘5.0’).  If not trapped,
     returns the result unchanged.  This signal is used to detect loss
     of significant digits.

 -- Class: decimal.Subnormal

     Exponent was lower than *note Emin: 10eb. prior to rounding.

     Occurs when an operation result is subnormal (the exponent is too
     small).  If not trapped, returns the result unchanged.

 -- Class: decimal.Underflow

     Numerical underflow with result rounded to zero.

     Occurs when a subnormal result is pushed to zero by rounding.
     *note Inexact: 280e. and *note Subnormal: 2810. are also signaled.

 -- Class: decimal.FloatOperation

     Enable stricter semantics for mixing floats and Decimals.

     If the signal is not trapped (default), mixing floats and Decimals
     is permitted in the *note Decimal: 29d. constructor, *note
     create_decimal(): 10ed. and all comparison operators.  Both
     conversion and comparisons are exact.  Any occurrence of a mixed
     operation is silently recorded by setting ‘FloatOperation’ in the
     context flags.  Explicit conversions with *note from_float(): 1249.
     or *note create_decimal_from_float(): 2854. do not set the flag.

     Otherwise (the signal is trapped), only equality comparisons and
     explicit conversions are silent.  All other mixed operations raise
     ‘FloatOperation’.

The following table summarizes the hierarchy of signals:

     exceptions.ArithmeticError(exceptions.Exception)
         DecimalException
             Clamped
             DivisionByZero(DecimalException, exceptions.ZeroDivisionError)
             Inexact
                 Overflow(Inexact, Rounded)
                 Underflow(Inexact, Rounded, Subnormal)
             InvalidOperation
             Rounded
             Subnormal
             FloatOperation(DecimalException, exceptions.TypeError)


File: python.info,  Node: Floating-point notes,  Next: Working with threads,  Prev: Signals,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.8 Floating-point notes
............................

* Menu:

* Mitigating round-off error with increased precision::
* Special values::


File: python.info,  Node: Mitigating round-off error with increased precision,  Next: Special values,  Up: Floating-point notes

5.9.4.9 Mitigating round-off error with increased precision
...........................................................

The use of decimal floating point eliminates decimal representation
error (making it possible to represent ‘0.1’ exactly); however, some
operations can still incur round-off error when non-zero digits exceed
the fixed precision.

The effects of round-off error can be amplified by the addition or
subtraction of nearly offsetting quantities resulting in loss of
significance.  Knuth provides two instructive examples where rounded
floating-point arithmetic with insufficient precision causes the
breakdown of the associative and distributive properties of addition:

     # Examples from Seminumerical Algorithms, Section 4.2.2.
     >>> from decimal import Decimal, getcontext
     >>> getcontext().prec = 8

     >>> u, v, w = Decimal(11111113), Decimal(-11111111), Decimal('7.51111111')
     >>> (u + v) + w
     Decimal('9.5111111')
     >>> u + (v + w)
     Decimal('10')

     >>> u, v, w = Decimal(20000), Decimal(-6), Decimal('6.0000003')
     >>> (u*v) + (u*w)
     Decimal('0.01')
     >>> u * (v+w)
     Decimal('0.0060000')

The ‘decimal’ module makes it possible to restore the identities by
expanding the precision sufficiently to avoid loss of significance:

     >>> getcontext().prec = 20
     >>> u, v, w = Decimal(11111113), Decimal(-11111111), Decimal('7.51111111')
     >>> (u + v) + w
     Decimal('9.51111111')
     >>> u + (v + w)
     Decimal('9.51111111')
     >>>
     >>> u, v, w = Decimal(20000), Decimal(-6), Decimal('6.0000003')
     >>> (u*v) + (u*w)
     Decimal('0.0060000')
     >>> u * (v+w)
     Decimal('0.0060000')


File: python.info,  Node: Special values,  Prev: Mitigating round-off error with increased precision,  Up: Floating-point notes

5.9.4.10 Special values
.......................

The number system for the ‘decimal’ module provides special values
including ‘NaN’, ‘sNaN’, ‘-Infinity’, ‘Infinity’, and two zeros, ‘+0’
and ‘-0’.

Infinities can be constructed directly with: ‘Decimal('Infinity')’.
Also, they can arise from dividing by zero when the *note
DivisionByZero: 280d. signal is not trapped.  Likewise, when the *note
Overflow: 2811. signal is not trapped, infinity can result from rounding
beyond the limits of the largest representable number.

The infinities are signed (affine) and can be used in arithmetic
operations where they get treated as very large, indeterminate numbers.
For instance, adding a constant to infinity gives another infinite
result.

Some operations are indeterminate and return ‘NaN’, or if the *note
InvalidOperation: 10ec. signal is trapped, raise an exception.  For
example, ‘0/0’ returns ‘NaN’ which means “not a number”.  This variety
of ‘NaN’ is quiet and, once created, will flow through other
computations always resulting in another ‘NaN’.  This behavior can be
useful for a series of computations that occasionally have missing
inputs — it allows the calculation to proceed while flagging specific
results as invalid.

A variant is ‘sNaN’ which signals rather than remaining quiet after
every operation.  This is a useful return value when an invalid result
needs to interrupt a calculation for special handling.

The behavior of Python’s comparison operators can be a little surprising
where a ‘NaN’ is involved.  A test for equality where one of the
operands is a quiet or signaling ‘NaN’ always returns *note False: b4f.
(even when doing ‘Decimal('NaN')==Decimal('NaN')’), while a test for
inequality always returns *note True: c2d.  An attempt to compare two
Decimals using any of the ‘<’, ‘<=’, ‘>’ or ‘>=’ operators will raise
the *note InvalidOperation: 10ec. signal if either operand is a ‘NaN’,
and return ‘False’ if this signal is not trapped.  Note that the General
Decimal Arithmetic specification does not specify the behavior of direct
comparisons; these rules for comparisons involving a ‘NaN’ were taken
from the IEEE 854 standard (see Table 3 in section 5.7).  To ensure
strict standards-compliance, use the *note compare(): 281c. and *note
compare_signal(): 281d. methods instead.

The signed zeros can result from calculations that underflow.  They keep
the sign that would have resulted if the calculation had been carried
out to greater precision.  Since their magnitude is zero, both positive
and negative zeros are treated as equal and their sign is informational.

In addition to the two signed zeros which are distinct yet equal, there
are various representations of zero with differing precisions yet
equivalent in value.  This takes a bit of getting used to.  For an eye
accustomed to normalized floating-point representations, it is not
immediately obvious that the following calculation returns a value equal
to zero:

     >>> 1 / Decimal('Infinity')
     Decimal('0E-1000026')


File: python.info,  Node: Working with threads,  Next: Recipes,  Prev: Floating-point notes,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.11 Working with threads
.............................

The *note getcontext(): 16dc. function accesses a different *note
Context: 10f3. object for each thread.  Having separate thread contexts
means that threads may make changes (such as ‘getcontext().prec=10’)
without interfering with other threads.

Likewise, the *note setcontext(): 2815. function automatically assigns
its target to the current thread.

If *note setcontext(): 2815. has not been called before *note
getcontext(): 16dc, then ‘getcontext()’ will automatically create a new
context for use in the current thread.

The new context is copied from a prototype context called
'DefaultContext'.  To control the defaults so that each thread will use
the same values throughout the application, directly modify the
'DefaultContext' object.  This should be done 'before' any threads are
started so that there won’t be a race condition between threads calling
*note getcontext(): 16dc.  For example:

     # Set applicationwide defaults for all threads about to be launched
     DefaultContext.prec = 12
     DefaultContext.rounding = ROUND_DOWN
     DefaultContext.traps = ExtendedContext.traps.copy()
     DefaultContext.traps[InvalidOperation] = 1
     setcontext(DefaultContext)

     # Afterwards, the threads can be started
     t1.start()
     t2.start()
     t3.start()
      . . .


File: python.info,  Node: Recipes,  Next: Decimal FAQ,  Prev: Working with threads,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.12 Recipes
................

Here are a few recipes that serve as utility functions and that
demonstrate ways to work with the *note Decimal: 29d. class:

     def moneyfmt(value, places=2, curr='', sep=',', dp='.',
                  pos='', neg='-', trailneg=''):
         """Convert Decimal to a money formatted string.

         places:  required number of places after the decimal point
         curr:    optional currency symbol before the sign (may be blank)
         sep:     optional grouping separator (comma, period, space, or blank)
         dp:      decimal point indicator (comma or period)
                  only specify as blank when places is zero
         pos:     optional sign for positive numbers: '+', space or blank
         neg:     optional sign for negative numbers: '-', '(', space or blank
         trailneg:optional trailing minus indicator:  '-', ')', space or blank

         >>> d = Decimal('-1234567.8901')
         >>> moneyfmt(d, curr='$')
         '-$1,234,567.89'
         >>> moneyfmt(d, places=0, sep='.', dp='', neg='', trailneg='-')
         '1.234.568-'
         >>> moneyfmt(d, curr='$', neg='(', trailneg=')')
         '($1,234,567.89)'
         >>> moneyfmt(Decimal(123456789), sep=' ')
         '123 456 789.00'
         >>> moneyfmt(Decimal('-0.02'), neg='<', trailneg='>')
         '<0.02>'

         """
         q = Decimal(10) ** -places      # 2 places --> '0.01'
         sign, digits, exp = value.quantize(q).as_tuple()
         result = []
         digits = list(map(str, digits))
         build, next = result.append, digits.pop
         if sign:
             build(trailneg)
         for i in range(places):
             build(next() if digits else '0')
         if places:
             build(dp)
         if not digits:
             build('0')
         i = 0
         while digits:
             build(next())
             i += 1
             if i == 3 and digits:
                 i = 0
                 build(sep)
         build(curr)
         build(neg if sign else pos)
         return ''.join(reversed(result))

     def pi():
         """Compute Pi to the current precision.

         >>> print(pi())
         3.141592653589793238462643383

         """
         getcontext().prec += 2  # extra digits for intermediate steps
         three = Decimal(3)      # substitute "three=3.0" for regular floats
         lasts, t, s, n, na, d, da = 0, three, 3, 1, 0, 0, 24
         while s != lasts:
             lasts = s
             n, na = n+na, na+8
             d, da = d+da, da+32
             t = (t * n) / d
             s += t
         getcontext().prec -= 2
         return +s               # unary plus applies the new precision

     def exp(x):
         """Return e raised to the power of x.  Result type matches input type.

         >>> print(exp(Decimal(1)))
         2.718281828459045235360287471
         >>> print(exp(Decimal(2)))
         7.389056098930650227230427461
         >>> print(exp(2.0))
         7.38905609893
         >>> print(exp(2+0j))
         (7.38905609893+0j)

         """
         getcontext().prec += 2
         i, lasts, s, fact, num = 0, 0, 1, 1, 1
         while s != lasts:
             lasts = s
             i += 1
             fact *= i
             num *= x
             s += num / fact
         getcontext().prec -= 2
         return +s

     def cos(x):
         """Return the cosine of x as measured in radians.

         The Taylor series approximation works best for a small value of x.
         For larger values, first compute x = x % (2 * pi).

         >>> print(cos(Decimal('0.5')))
         0.8775825618903727161162815826
         >>> print(cos(0.5))
         0.87758256189
         >>> print(cos(0.5+0j))
         (0.87758256189+0j)

         """
         getcontext().prec += 2
         i, lasts, s, fact, num, sign = 0, 0, 1, 1, 1, 1
         while s != lasts:
             lasts = s
             i += 2
             fact *= i * (i-1)
             num *= x * x
             sign *= -1
             s += num / fact * sign
         getcontext().prec -= 2
         return +s

     def sin(x):
         """Return the sine of x as measured in radians.

         The Taylor series approximation works best for a small value of x.
         For larger values, first compute x = x % (2 * pi).

         >>> print(sin(Decimal('0.5')))
         0.4794255386042030002732879352
         >>> print(sin(0.5))
         0.479425538604
         >>> print(sin(0.5+0j))
         (0.479425538604+0j)

         """
         getcontext().prec += 2
         i, lasts, s, fact, num, sign = 1, 0, x, 1, x, 1
         while s != lasts:
             lasts = s
             i += 2
             fact *= i * (i-1)
             num *= x * x
             sign *= -1
             s += num / fact * sign
         getcontext().prec -= 2
         return +s


File: python.info,  Node: Decimal FAQ,  Prev: Recipes,  Up: decimal — Decimal fixed-point and floating-point arithmetic

5.9.4.13 Decimal FAQ
....................

Q: It is cumbersome to type ‘decimal.Decimal('1234.5')’.  Is there a way
to minimize typing when using the interactive interpreter?

A: Some users abbreviate the constructor to just a single letter:

     >>> D = decimal.Decimal
     >>> D('1.23') + D('3.45')
     Decimal('4.68')

Q: In a fixed-point application with two decimal places, some inputs
have many places and need to be rounded.  Others are not supposed to
have excess digits and need to be validated.  What methods should be
used?

A: The *note quantize(): 10f4. method rounds to a fixed number of
decimal places.  If the *note Inexact: 280e. trap is set, it is also
useful for validation:

     >>> TWOPLACES = Decimal(10) ** -2       # same as Decimal('0.01')

     >>> # Round to two places
     >>> Decimal('3.214').quantize(TWOPLACES)
     Decimal('3.21')

     >>> # Validate that a number does not exceed two places
     >>> Decimal('3.21').quantize(TWOPLACES, context=Context(traps=[Inexact]))
     Decimal('3.21')

     >>> Decimal('3.214').quantize(TWOPLACES, context=Context(traps=[Inexact]))
     Traceback (most recent call last):
        ...
     Inexact: None

Q: Once I have valid two place inputs, how do I maintain that invariant
throughout an application?

A: Some operations like addition, subtraction, and multiplication by an
integer will automatically preserve fixed point.  Others operations,
like division and non-integer multiplication, will change the number of
decimal places and need to be followed-up with a *note quantize(): 10f4.
step:

     >>> a = Decimal('102.72')           # Initial fixed-point values
     >>> b = Decimal('3.17')
     >>> a + b                           # Addition preserves fixed-point
     Decimal('105.89')
     >>> a - b
     Decimal('99.55')
     >>> a * 42                          # So does integer multiplication
     Decimal('4314.24')
     >>> (a * b).quantize(TWOPLACES)     # Must quantize non-integer multiplication
     Decimal('325.62')
     >>> (b / a).quantize(TWOPLACES)     # And quantize division
     Decimal('0.03')

In developing fixed-point applications, it is convenient to define
functions to handle the *note quantize(): 10f4. step:

     >>> def mul(x, y, fp=TWOPLACES):
     ...     return (x * y).quantize(fp)
     ...
     >>> def div(x, y, fp=TWOPLACES):
     ...     return (x / y).quantize(fp)

     >>> mul(a, b)                       # Automatically preserve fixed-point
     Decimal('325.62')
     >>> div(b, a)
     Decimal('0.03')

Q: There are many ways to express the same value.  The numbers ‘200’,
‘200.000’, ‘2E2’, and ‘.02E+4’ all have the same value at various
precisions.  Is there a way to transform them to a single recognizable
canonical value?

A: The *note normalize(): 283d. method maps all equivalent values to a
single representative:

     >>> values = map(Decimal, '200 200.000 2E2 .02E+4'.split())
     >>> [v.normalize() for v in values]
     [Decimal('2E+2'), Decimal('2E+2'), Decimal('2E+2'), Decimal('2E+2')]

Q: When does rounding occur in a computation?

A: It occurs 'after' the computation.  The philosophy of the decimal
specification is that numbers are considered exact and are created
independent of the current context.  They can even have greater
precision than current context.  Computations process with those exact
inputs and then rounding (or other context operations) is applied to the
'result' of the computation:

     >>> getcontext().prec = 5
     >>> pi = Decimal('3.1415926535')   # More than 5 digits
     >>> pi                             # All digits are retained
     Decimal('3.1415926535')
     >>> pi + 0                         # Rounded after an addition
     Decimal('3.1416')
     >>> pi - Decimal('0.00005')        # Subtract unrounded numbers, then round
     Decimal('3.1415')
     >>> pi + 0 - Decimal('0.00005').   # Intermediate values are rounded
     Decimal('3.1416')

Q: Some decimal values always print with exponential notation.  Is there
a way to get a non-exponential representation?

A: For some values, exponential notation is the only way to express the
number of significant places in the coefficient.  For example,
expressing ‘5.0E+3’ as ‘5000’ keeps the value constant but cannot show
the original’s two-place significance.

If an application does not care about tracking significance, it is easy
to remove the exponent and trailing zeroes, losing significance, but
keeping the value unchanged:

     >>> def remove_exponent(d):
     ...     return d.quantize(Decimal(1)) if d == d.to_integral() else d.normalize()

     >>> remove_exponent(Decimal('5E+3'))
     Decimal('5000')

Q: Is there a way to convert a regular float to a *note Decimal: 29d.?

A: Yes, any binary floating-point number can be exactly expressed as a
Decimal though an exact conversion may take more precision than
intuition would suggest:

     >>> Decimal(math.pi)
     Decimal('3.141592653589793115997963468544185161590576171875')

Q: Within a complex calculation, how can I make sure that I haven’t
gotten a spurious result because of insufficient precision or rounding
anomalies.

A: The decimal module makes it easy to test results.  A best practice is
to re-run calculations using greater precision and with various rounding
modes.  Widely differing results indicate insufficient precision,
rounding mode issues, ill-conditioned inputs, or a numerically unstable
algorithm.

Q: I noticed that context precision is applied to the results of
operations but not to the inputs.  Is there anything to watch out for
when mixing values of different precisions?

A: Yes.  The principle is that all values are considered to be exact and
so is the arithmetic on those values.  Only the results are rounded.
The advantage for inputs is that “what you type is what you get”.  A
disadvantage is that the results can look odd if you forget that the
inputs haven’t been rounded:

     >>> getcontext().prec = 3
     >>> Decimal('3.104') + Decimal('2.104')
     Decimal('5.21')
     >>> Decimal('3.104') + Decimal('0.000') + Decimal('2.104')
     Decimal('5.20')

The solution is either to increase precision or to force rounding of
inputs using the unary plus operation:

     >>> getcontext().prec = 3
     >>> +Decimal('1.23456789')      # unary plus triggers rounding
     Decimal('1.23')

Alternatively, inputs can be rounded upon creation using the *note
Context.create_decimal(): 10ed. method:

     >>> Context(prec=5, rounding=ROUND_DOWN).create_decimal('1.2345678')
     Decimal('1.2345')

Q: Is the CPython implementation fast for large numbers?

A: Yes.  In the CPython and PyPy3 implementations, the C/CFFI versions
of the decimal module integrate the high speed libmpdec(1) library for
arbitrary precision correctly rounded decimal floating-point arithmetic
(2).  ‘libmpdec’ uses Karatsuba multiplication(3) for medium-sized
numbers and the Number Theoretic Transform(4) for very large numbers.

The context must be adapted for exact arbitrary precision arithmetic.
*note Emin: 10eb. and *note Emax: 10ea. should always be set to the
maximum values, *note clamp: 11e2. should always be 0 (the default).
Setting *note prec: 284d. requires some care.

The easiest approach for trying out bignum arithmetic is to use the
maximum value for *note prec: 284d. as well (5):

     >>> setcontext(Context(prec=MAX_PREC, Emax=MAX_EMAX, Emin=MIN_EMIN))
     >>> x = Decimal(2) ** 256
     >>> x / 128
     Decimal('904625697166532776746648320380374280103671755200316906558262375061821325312')

For inexact results, *note MAX_PREC: 10e4. is far too large on 64-bit
platforms and the available memory will be insufficient:

     >>> Decimal(1) / 3
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     MemoryError

On systems with overallocation (e.g.  Linux), a more sophisticated
approach is to adjust *note prec: 284d. to the amount of available RAM.
Suppose that you have 8GB of RAM and expect 10 simultaneous operands
using a maximum of 500MB each:

     >>> import sys
     >>>
     >>> # Maximum number of digits for a single operand using 500MB in 8-byte words
     >>> # with 19 digits per word (4-byte and 9 digits for the 32-bit build):
     >>> maxdigits = 19 * ((500 * 1024**2) // 8)
     >>>
     >>> # Check that this works:
     >>> c = Context(prec=maxdigits, Emax=MAX_EMAX, Emin=MIN_EMIN)
     >>> c.traps[Inexact] = True
     >>> setcontext(c)
     >>>
     >>> # Fill the available precision with nines:
     >>> x = Decimal(0).logical_invert() * 9
     >>> sys.getsizeof(x)
     524288112
     >>> x + 2
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       decimal.Inexact: [<class 'decimal.Inexact'>]

In general (and especially on systems without overallocation), it is
recommended to estimate even tighter bounds and set the *note Inexact:
280e. trap if all calculations are expected to be exact.

   ---------- Footnotes ----------

   (1) https://www.bytereef.org/mpdecimal/doc/libmpdec/index.html

   (2) 
Added in version 3.3.

   (3) https://en.wikipedia.org/wiki/Karatsuba_algorithm

   (4) 
https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general)#Number-theoretic_transform

   (5) 
Changed in version 3.9: This approach now works for all exact results
except for non-integer powers.


File: python.info,  Node: fractions — Rational numbers,  Next: random — Generate pseudo-random numbers,  Prev: decimal — Decimal fixed-point and floating-point arithmetic,  Up: Numeric and Mathematical Modules

5.9.5 ‘fractions’ — Rational numbers
------------------------------------

'Source code:' Lib/fractions.py(1)

__________________________________________________________________

The ‘fractions’ module provides support for rational number arithmetic.

A Fraction instance can be constructed from a pair of rational numbers,
from a single number, or from a string.

 -- Class: fractions.Fraction (numerator=0, denominator=1)

 -- Class: fractions.Fraction (other_fraction)

 -- Class: fractions.Fraction (float)

 -- Class: fractions.Fraction (decimal)

 -- Class: fractions.Fraction (string)

     The first version requires that 'numerator' and 'denominator' are
     instances of *note numbers.Rational: 1306. and returns a new
     ‘Fraction’ instance with a value equal to ‘numerator/denominator’.
     If 'denominator' is zero, it raises a *note ZeroDivisionError: 94f.
     The second version requires that 'other_fraction' is an instance of
     ‘numbers.Rational’ and returns a ‘Fraction’ instance with the same
     value.  The next two versions accept either a *note float: 2f7. or
     a *note decimal.Decimal: 29d. instance, and return a ‘Fraction’
     instance with exactly the same value.  Note that due to the usual
     issues with binary floating point (see *note Floating-Point
     Arithmetic; Issues and Limitations: 1eb8.), the argument to
     ‘Fraction(1.1)’ is not exactly equal to 11/10, and so
     ‘Fraction(1.1)’ does 'not' return ‘Fraction(11, 10)’ as one might
     expect.  (But see the documentation for the *note
     limit_denominator(): 28a1. method below.)  The last version of the
     constructor expects a string or unicode instance.  The usual form
     for this instance is:

          [sign] numerator ['/' denominator]

     where the optional ‘sign’ may be either ‘+’ or ‘-’ and ‘numerator’
     and ‘denominator’ (if present) are strings of decimal digits
     (underscores may be used to delimit digits as with integral
     literals in code).  In addition, any string that represents a
     finite value and is accepted by the *note float: 2f7. constructor
     is also accepted by the ‘Fraction’ constructor.  In either form the
     input string may also have leading and/or trailing whitespace.
     Here are some examples:

          >>> from fractions import Fraction
          >>> Fraction(16, -10)
          Fraction(-8, 5)
          >>> Fraction(123)
          Fraction(123, 1)
          >>> Fraction()
          Fraction(0, 1)
          >>> Fraction('3/7')
          Fraction(3, 7)
          >>> Fraction(' -3/7 ')
          Fraction(-3, 7)
          >>> Fraction('1.414213 \t\n')
          Fraction(1414213, 1000000)
          >>> Fraction('-.125')
          Fraction(-1, 8)
          >>> Fraction('7e-6')
          Fraction(7, 1000000)
          >>> Fraction(2.25)
          Fraction(9, 4)
          >>> Fraction(1.1)
          Fraction(2476979795053773, 2251799813685248)
          >>> from decimal import Decimal
          >>> Fraction(Decimal('1.1'))
          Fraction(11, 10)

     The ‘Fraction’ class inherits from the abstract base class *note
     numbers.Rational: 1306, and implements all of the methods and
     operations from that class.  ‘Fraction’ instances are *note
     hashable: 613, and should be treated as immutable.  In addition,
     ‘Fraction’ has the following properties and methods:

     Changed in version 3.2: The ‘Fraction’ constructor now accepts
     *note float: 2f7. and *note decimal.Decimal: 29d. instances.

     Changed in version 3.9: The *note math.gcd(): 919. function is now
     used to normalize the 'numerator' and 'denominator'.  ‘math.gcd()’
     always returns an *note int: 257. type.  Previously, the GCD type
     depended on 'numerator' and 'denominator'.

     Changed in version 3.11: Underscores are now permitted when
     creating a ‘Fraction’ instance from a string, following PEP 515(2)
     rules.

     Changed in version 3.11: ‘Fraction’ implements ‘__int__’ now to
     satisfy ‘typing.SupportsInt’ instance checks.

     Changed in version 3.12: Space is allowed around the slash for
     string inputs: ‘Fraction('2 / 3')’.

     Changed in version 3.12: ‘Fraction’ instances now support
     float-style formatting, with presentation types ‘"e"’, ‘"E"’,
     ‘"f"’, ‘"F"’, ‘"g"’, ‘"G"’ and ‘"%""’.

     Changed in version 3.13: Formatting of ‘Fraction’ instances without
     a presentation type now supports fill, alignment, sign handling,
     minimum width and grouping.

      -- Attribute: numerator

          Numerator of the Fraction in lowest term.

      -- Attribute: denominator

          Denominator of the Fraction in lowest terms.  Guaranteed to be
          positive.

      -- Method: as_integer_ratio ()

          Return a tuple of two integers, whose ratio is equal to the
          original Fraction.  The ratio is in lowest terms and has a
          positive denominator.

          Added in version 3.8.

      -- Method: is_integer ()

          Return ‘True’ if the Fraction is an integer.

          Added in version 3.12.

      -- Method: classmethod from_float (f)

          Alternative constructor which only accepts instances of *note
          float: 2f7. or *note numbers.Integral: 216f.  Beware that
          ‘Fraction.from_float(0.3)’ is not the same value as
          ‘Fraction(3, 10)’.

               Note: From Python 3.2 onwards, you can also construct a
               ‘Fraction’ instance directly from a *note float: 2f7.

      -- Method: classmethod from_decimal (dec)

          Alternative constructor which only accepts instances of *note
          decimal.Decimal: 29d. or *note numbers.Integral: 216f.

               Note: From Python 3.2 onwards, you can also construct a
               ‘Fraction’ instance directly from a *note
               decimal.Decimal: 29d. instance.

      -- Method: limit_denominator (max_denominator=1000000)

          Finds and returns the closest ‘Fraction’ to ‘self’ that has
          denominator at most max_denominator.  This method is useful
          for finding rational approximations to a given floating-point
          number:

               >>> from fractions import Fraction
               >>> Fraction('3.1415926535897932').limit_denominator(1000)
               Fraction(355, 113)

          or for recovering a rational number that’s represented as a
          float:

               >>> from math import pi, cos
               >>> Fraction(cos(pi/3))
               Fraction(4503599627370497, 9007199254740992)
               >>> Fraction(cos(pi/3)).limit_denominator()
               Fraction(1, 2)
               >>> Fraction(1.1).limit_denominator()
               Fraction(11, 10)

      -- Method: __floor__ ()

          Returns the greatest *note int: 257. ‘<= self’.  This method
          can also be accessed through the *note math.floor(): 140a.
          function:

               >>> from math import floor
               >>> floor(Fraction(355, 113))
               3

      -- Method: __ceil__ ()

          Returns the least *note int: 257. ‘>= self’.  This method can
          also be accessed through the *note math.ceil(): 140b.
          function.

      -- Method: __round__ ()

      -- Method: __round__ (ndigits)

          The first version returns the nearest *note int: 257. to
          ‘self’, rounding half to even.  The second version rounds
          ‘self’ to the nearest multiple of ‘Fraction(1, 10**ndigits)’
          (logically, if ‘ndigits’ is negative), again rounding half
          toward even.  This method can also be accessed through the
          *note round(): 1322. function.

      -- Method: __format__ (format_spec, /)

          Provides support for formatting of ‘Fraction’ instances via
          the *note str.format(): 624. method, the *note format(): 622.
          built-in function, or *note Formatted string literals: 9b4.

          If the ‘format_spec’ format specification string does not end
          with one of the presentation types ‘'e'’, ‘'E'’, ‘'f'’, ‘'F'’,
          ‘'g'’, ‘'G'’ or ‘'%'’ then formatting follows the general
          rules for fill, alignment, sign handling, minimum width, and
          grouping as described in the *note format specification
          mini-language: 1e8.  The “alternate form” flag ‘'#'’ is
          supported: if present, it forces the output string to always
          include an explicit denominator, even when the value being
          formatted is an exact integer.  The zero-fill flag ‘'0'’ is
          not supported.

          If the ‘format_spec’ format specification string ends with one
          of the presentation types ‘'e'’, ‘'E'’, ‘'f'’, ‘'F'’, ‘'g'’,
          ‘'G'’ or ‘'%'’ then formatting follows the rules outlined for
          the *note float: 2f7. type in the *note Format specification
          mini-language: 1e8. section.

          Here are some examples:

               >>> from fractions import Fraction
               >>> format(Fraction(103993, 33102), '_')
               '103_993/33_102'
               >>> format(Fraction(1, 7), '.^+10')
               '...+1/7...'
               >>> format(Fraction(3, 1), '')
               '3'
               >>> format(Fraction(3, 1), '#')
               '3/1'
               >>> format(Fraction(1, 7), '.40g')
               '0.1428571428571428571428571428571428571429'
               >>> format(Fraction('1234567.855'), '_.2f')
               '1_234_567.86'
               >>> f"{Fraction(355, 113):*>20.6e}"
               '********3.141593e+00'
               >>> old_price, new_price = 499, 672
               >>> "{:.2%} price increase".format(Fraction(new_price, old_price) - 1)
               '34.67% price increase'

See also
........

Module *note numbers: 9e.

     The abstract base classes making up the numeric tower.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/fractions.py

   (2) https://peps.python.org/pep-0515/


File: python.info,  Node: random — Generate pseudo-random numbers,  Next: statistics — Mathematical statistics functions,  Prev: fractions — Rational numbers,  Up: Numeric and Mathematical Modules

5.9.6 ‘random’ — Generate pseudo-random numbers
-----------------------------------------------

'Source code:' Lib/random.py(1)

__________________________________________________________________

This module implements pseudo-random number generators for various
distributions.

For integers, there is uniform selection from a range.  For sequences,
there is uniform selection of a random element, a function to generate a
random permutation of a list in-place, and a function for random
sampling without replacement.

On the real line, there are functions to compute uniform, normal
(Gaussian), lognormal, negative exponential, gamma, and beta
distributions.  For generating distributions of angles, the von Mises
distribution is available.

Almost all module functions depend on the basic function *note random():
74b, which generates a random float uniformly in the half-open range
‘0.0 <= X < 1.0’.  Python uses the Mersenne Twister as the core
generator.  It produces 53-bit precision floats and has a period of
2**19937-1.  The underlying implementation in C is both fast and
threadsafe.  The Mersenne Twister is one of the most extensively tested
random number generators in existence.  However, being completely
deterministic, it is not suitable for all purposes, and is completely
unsuitable for cryptographic purposes.

The functions supplied by this module are actually bound methods of a
hidden instance of the *note random.Random: 1a02. class.  You can
instantiate your own instances of *note Random: 1a02. to get generators
that don’t share state.

Class *note Random: 1a02. can also be subclassed if you want to use a
different basic generator of your own devising: see the documentation on
that class for more details.

The ‘random’ module also provides the *note SystemRandom: 28aa. class
which uses the system function *note os.urandom(): 526. to generate
random numbers from sources provided by the operating system.

     Warning: The pseudo-random generators of this module should not be
     used for security purposes.  For security or cryptographic uses,
     see the *note secrets: c0. module.

See also
........

M. Matsumoto and T. Nishimura, “Mersenne Twister: A 623-dimensionally
equidistributed uniform pseudorandom number generator”, ACM Transactions
on Modeling and Computer Simulation Vol.  8, No.  1, January pp.3–30
1998.

Complementary-Multiply-with-Carry recipe(2) for a compatible alternative
random number generator with a long period and comparatively simple
update operations.

     Note: The global random number generator and instances of *note
     Random: 1a02. are thread-safe.  However, in the free-threaded
     build, concurrent calls to the global generator or to the same
     instance of ‘Random’ may encounter contention and poor performance.
     Consider using separate instances of ‘Random’ per thread instead.

* Menu:

* Bookkeeping functions::
* Functions for bytes::
* Functions for integers::
* Functions for sequences::
* Discrete distributions::
* Real-valued distributions::
* Alternative Generator::
* Notes on Reproducibility::
* Examples: Examples<4>.
* Recipes: Recipes<2>.
* Command-line usage::
* Command-line example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/random.py

   (2) 
https://code.activestate.com/recipes/576707-long-period-random-number-generator/


File: python.info,  Node: Bookkeeping functions,  Next: Functions for bytes,  Up: random — Generate pseudo-random numbers

5.9.6.1 Bookkeeping functions
.............................

 -- Function: random.seed (a=None, version=2)

     Initialize the random number generator.

     If 'a' is omitted or ‘None’, the current system time is used.  If
     randomness sources are provided by the operating system, they are
     used instead of the system time (see the *note os.urandom(): 526.
     function for details on availability).

     If 'a' is an int, its absolute value is used directly.

     With version 2 (the default), a *note str: 44f, *note bytes: 1c2,
     or *note bytearray: 2ea. object gets converted to an *note int:
     257. and all of its bits are used.

     With version 1 (provided for reproducing random sequences from
     older versions of Python), the algorithm for *note str: 44f. and
     *note bytes: 1c2. generates a narrower range of seeds.

     Changed in version 3.2: Moved to the version 2 scheme which uses
     all of the bits in a string seed.

     Changed in version 3.11: The 'seed' must be one of the following
     types: ‘None’, *note int: 257, *note float: 2f7, *note str: 44f,
     *note bytes: 1c2, or *note bytearray: 2ea.

 -- Function: random.getstate ()

     Return an object capturing the current internal state of the
     generator.  This object can be passed to *note setstate(): 28ad. to
     restore the state.

 -- Function: random.setstate (state)

     'state' should have been obtained from a previous call to *note
     getstate(): 28ac, and ‘setstate()’ restores the internal state of
     the generator to what it was at the time ‘getstate()’ was called.


File: python.info,  Node: Functions for bytes,  Next: Functions for integers,  Prev: Bookkeeping functions,  Up: random — Generate pseudo-random numbers

5.9.6.2 Functions for bytes
...........................

 -- Function: random.randbytes (n)

     Generate 'n' random bytes.

     This method should not be used for generating security tokens.  Use
     *note secrets.token_bytes(): 28af. instead.

     Added in version 3.9.


File: python.info,  Node: Functions for integers,  Next: Functions for sequences,  Prev: Functions for bytes,  Up: random — Generate pseudo-random numbers

5.9.6.3 Functions for integers
..............................

 -- Function: random.randrange (stop)

 -- Function: random.randrange (start, stop[, step])

     Return a randomly selected element from ‘range(start, stop, step)’.

     This is roughly equivalent to ‘choice(range(start, stop, step))’
     but supports arbitrarily large ranges and is optimized for common
     cases.

     The positional argument pattern matches the *note range(): 94d.
     function.

     Keyword arguments should not be used because they can be
     interpreted in unexpected ways.  For example ‘randrange(start=100)’
     is interpreted as ‘randrange(0, 100, 1)’.

     Changed in version 3.2: *note randrange(): 872. is more
     sophisticated about producing equally distributed values.  Formerly
     it used a style like ‘int(random()*n)’ which could produce slightly
     uneven distributions.

     Changed in version 3.12: Automatic conversion of non-integer types
     is no longer supported.  Calls such as ‘randrange(10.0)’ and
     ‘randrange(Fraction(10, 1))’ now raise a *note TypeError: 2c3.

 -- Function: random.randint (a, b)

     Return a random integer 'N' such that ‘a <= N <= b’.  Alias for
     ‘randrange(a, b+1)’.

 -- Function: random.getrandbits (k)

     Returns a non-negative Python integer with 'k' random bits.  This
     method is supplied with the Mersenne Twister generator and some
     other generators may also provide it as an optional part of the
     API.  When available, *note getrandbits(): 1048. enables *note
     randrange(): 872. to handle arbitrarily large ranges.

     Changed in version 3.9: This method now accepts zero for 'k'.


File: python.info,  Node: Functions for sequences,  Next: Discrete distributions,  Prev: Functions for integers,  Up: random — Generate pseudo-random numbers

5.9.6.4 Functions for sequences
...............................

 -- Function: random.choice (seq)

     Return a random element from the non-empty sequence 'seq'.  If
     'seq' is empty, raises *note IndexError: 1585.

 -- Function: random.choices (population, weights=None, *,
          cum_weights=None, k=1)

     Return a 'k' sized list of elements chosen from the 'population'
     with replacement.  If the 'population' is empty, raises *note
     IndexError: 1585.

     If a 'weights' sequence is specified, selections are made according
     to the relative weights.  Alternatively, if a 'cum_weights'
     sequence is given, the selections are made according to the
     cumulative weights (perhaps computed using *note
     itertools.accumulate(): a08.).  For example, the relative weights
     ‘[10, 5, 30, 5]’ are equivalent to the cumulative weights ‘[10, 15,
     45, 50]’.  Internally, the relative weights are converted to
     cumulative weights before making selections, so supplying the
     cumulative weights saves work.

     If neither 'weights' nor 'cum_weights' are specified, selections
     are made with equal probability.  If a weights sequence is
     supplied, it must be the same length as the 'population' sequence.
     It is a *note TypeError: 2c3. to specify both 'weights' and
     'cum_weights'.

     The 'weights' or 'cum_weights' can use any numeric type that
     interoperates with the *note float: 2f7. values returned by *note
     random(): b8. (that includes integers, floats, and fractions but
     excludes decimals).  Weights are assumed to be non-negative and
     finite.  A *note ValueError: 202. is raised if all weights are
     zero.

     For a given seed, the ‘choices()’ function with equal weighting
     typically produces a different sequence than repeated calls to
     *note choice(): 1276.  The algorithm used by ‘choices()’ uses
     floating-point arithmetic for internal consistency and speed.  The
     algorithm used by ‘choice()’ defaults to integer arithmetic with
     repeated selections to avoid small biases from round-off error.

     Added in version 3.6.

     Changed in version 3.9: Raises a *note ValueError: 202. if all
     weights are zero.

 -- Function: random.shuffle (x)

     Shuffle the sequence 'x' in place.

     To shuffle an immutable sequence and return a new shuffled list,
     use ‘sample(x, k=len(x))’ instead.

     Note that even for small ‘len(x)’, the total number of permutations
     of 'x' can quickly grow larger than the period of most random
     number generators.  This implies that most permutations of a long
     sequence can never be generated.  For example, a sequence of length
     2080 is the largest that can fit within the period of the Mersenne
     Twister random number generator.

     Changed in version 3.11: Removed the optional parameter 'random'.

 -- Function: random.sample (population, k, *, counts=None)

     Return a 'k' length list of unique elements chosen from the
     population sequence.  Used for random sampling without replacement.

     Returns a new list containing elements from the population while
     leaving the original population unchanged.  The resulting list is
     in selection order so that all sub-slices will also be valid random
     samples.  This allows raffle winners (the sample) to be partitioned
     into grand prize and second place winners (the subslices).

     Members of the population need not be *note hashable: 613. or
     unique.  If the population contains repeats, then each occurrence
     is a possible selection in the sample.

     Repeated elements can be specified one at a time or with the
     optional keyword-only 'counts' parameter.  For example,
     ‘sample(['red', 'blue'], counts=[4, 2], k=5)’ is equivalent to
     ‘sample(['red', 'red', 'red', 'red', 'blue', 'blue'], k=5)’.

     To choose a sample from a range of integers, use a *note range():
     94d. object as an argument.  This is especially fast and space
     efficient for sampling from a large population:
     ‘sample(range(10000000), k=60)’.

     If the sample size is larger than the population size, a *note
     ValueError: 202. is raised.

     Changed in version 3.9: Added the 'counts' parameter.

     Changed in version 3.11: The 'population' must be a sequence.
     Automatic conversion of sets to lists is no longer supported.


File: python.info,  Node: Discrete distributions,  Next: Real-valued distributions,  Prev: Functions for sequences,  Up: random — Generate pseudo-random numbers

5.9.6.5 Discrete distributions
..............................

The following function generates a discrete distribution.

 -- Function: random.binomialvariate (n=1, p=0.5)

     Binomial distribution(1).  Return the number of successes for 'n'
     independent trials with the probability of success in each trial
     being 'p':

     Mathematically equivalent to:

          sum(random() < p for i in range(n))

     The number of trials 'n' should be a non-negative integer.  The
     probability of success 'p' should be between ‘0.0 <= p <= 1.0’.
     The result is an integer in the range ‘0 <= X <= n’.

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) https://mathworld.wolfram.com/BinomialDistribution.html


File: python.info,  Node: Real-valued distributions,  Next: Alternative Generator,  Prev: Discrete distributions,  Up: random — Generate pseudo-random numbers

5.9.6.6 Real-valued distributions
.................................

The following functions generate specific real-valued distributions.
Function parameters are named after the corresponding variables in the
distribution’s equation, as used in common mathematical practice; most
of these equations can be found in any statistics text.

 -- Function: random.random ()

     Return the next random floating-point number in the range ‘0.0 <= X
     < 1.0’

 -- Function: random.uniform (a, b)

     Return a random floating-point number 'N' such that ‘a <= N <= b’
     for ‘a <= b’ and ‘b <= N <= a’ for ‘b < a’.

     The end-point value ‘b’ may or may not be included in the range
     depending on floating-point rounding in the expression ‘a + (b-a) *
     random()’.

 -- Function: random.triangular (low, high, mode)

     Return a random floating-point number 'N' such that ‘low <= N <=
     high’ and with the specified 'mode' between those bounds.  The
     'low' and 'high' bounds default to zero and one.  The 'mode'
     argument defaults to the midpoint between the bounds, giving a
     symmetric distribution.

 -- Function: random.betavariate (alpha, beta)

     Beta distribution.  Conditions on the parameters are ‘alpha > 0’
     and ‘beta > 0’.  Returned values range between 0 and 1.

 -- Function: random.expovariate (lambd=1.0)

     Exponential distribution.  'lambd' is 1.0 divided by the desired
     mean.  It should be nonzero.  (The parameter would be called
     “lambda”, but that is a reserved word in Python.)  Returned values
     range from 0 to positive infinity if 'lambd' is positive, and from
     negative infinity to 0 if 'lambd' is negative.

     Changed in version 3.12: Added the default value for ‘lambd’.

 -- Function: random.gammavariate (alpha, beta)

     Gamma distribution.  ('Not' the gamma function!)  The shape and
     scale parameters, 'alpha' and 'beta', must have positive values.
     (Calling conventions vary and some sources define ‘beta’ as the
     inverse of the scale).

     The probability distribution function is:

                    x ** (alpha - 1) * math.exp(-x / beta)
          pdf(x) =  --------------------------------------
                      math.gamma(alpha) * beta ** alpha

 -- Function: random.gauss (mu=0.0, sigma=1.0)

     Normal distribution, also called the Gaussian distribution.  'mu'
     is the mean, and 'sigma' is the standard deviation.  This is
     slightly faster than the *note normalvariate(): 197e. function
     defined below.

     Multithreading note: When two threads call this function
     simultaneously, it is possible that they will receive the same
     return value.  This can be avoided in three ways.  1) Have each
     thread use a different instance of the random number generator.  2)
     Put locks around all calls.  3) Use the slower, but thread-safe
     *note normalvariate(): 197e. function instead.

     Changed in version 3.11: 'mu' and 'sigma' now have default
     arguments.

 -- Function: random.lognormvariate (mu, sigma)

     Log normal distribution.  If you take the natural logarithm of this
     distribution, you’ll get a normal distribution with mean 'mu' and
     standard deviation 'sigma'.  'mu' can have any value, and 'sigma'
     must be greater than zero.

 -- Function: random.normalvariate (mu=0.0, sigma=1.0)

     Normal distribution.  'mu' is the mean, and 'sigma' is the standard
     deviation.

     Changed in version 3.11: 'mu' and 'sigma' now have default
     arguments.

 -- Function: random.vonmisesvariate (mu, kappa)

     'mu' is the mean angle, expressed in radians between 0 and 2*'pi',
     and 'kappa' is the concentration parameter, which must be greater
     than or equal to zero.  If 'kappa' is equal to zero, this
     distribution reduces to a uniform random angle over the range 0 to
     2*'pi'.

 -- Function: random.paretovariate (alpha)

     Pareto distribution.  'alpha' is the shape parameter.

 -- Function: random.weibullvariate (alpha, beta)

     Weibull distribution.  'alpha' is the scale parameter and 'beta' is
     the shape parameter.


File: python.info,  Node: Alternative Generator,  Next: Notes on Reproducibility,  Prev: Real-valued distributions,  Up: random — Generate pseudo-random numbers

5.9.6.7 Alternative Generator
.............................

 -- Class: random.Random ([seed])

     Class that implements the default pseudo-random number generator
     used by the ‘random’ module.

     Changed in version 3.11: Formerly the 'seed' could be any hashable
     object.  Now it is limited to: ‘None’, *note int: 257, *note float:
     2f7, *note str: 44f, *note bytes: 1c2, or *note bytearray: 2ea.

     Subclasses of ‘Random’ should override the following methods if
     they wish to make use of a different basic generator:

      -- Method: seed (a=None, version=2)

          Override this method in subclasses to customise the *note
          seed(): 12ba. behaviour of ‘Random’ instances.

      -- Method: getstate ()

          Override this method in subclasses to customise the *note
          getstate(): 28ac. behaviour of ‘Random’ instances.

      -- Method: setstate (state)

          Override this method in subclasses to customise the *note
          setstate(): 28ad. behaviour of ‘Random’ instances.

      -- Method: random ()

          Override this method in subclasses to customise the *note
          random(): 74b. behaviour of ‘Random’ instances.

     Optionally, a custom generator subclass can also supply the
     following method:

      -- Method: getrandbits (k)

          Override this method in subclasses to customise the *note
          getrandbits(): 1048. behaviour of ‘Random’ instances.

      -- Method: randbytes (n)

          Override this method in subclasses to customise the *note
          randbytes(): 1648. behaviour of ‘Random’ instances.

 -- Class: random.SystemRandom ([seed])

     Class that uses the *note os.urandom(): 526. function for
     generating random numbers from sources provided by the operating
     system.  Not available on all systems.  Does not rely on software
     state, and sequences are not reproducible.  Accordingly, the *note
     seed(): 12ba. method has no effect and is ignored.  The *note
     getstate(): 28ac. and *note setstate(): 28ad. methods raise *note
     NotImplementedError: 228. if called.


File: python.info,  Node: Notes on Reproducibility,  Next: Examples<4>,  Prev: Alternative Generator,  Up: random — Generate pseudo-random numbers

5.9.6.8 Notes on Reproducibility
................................

Sometimes it is useful to be able to reproduce the sequences given by a
pseudo-random number generator.  By reusing a seed value, the same
sequence should be reproducible from run to run as long as multiple
threads are not running.

Most of the random module’s algorithms and seeding functions are subject
to change across Python versions, but two aspects are guaranteed not to
change:

   * If a new seeding method is added, then a backward compatible seeder
     will be offered.

   * The generator’s *note random(): 28c0. method will continue to
     produce the same sequence when the compatible seeder is given the
     same seed.


File: python.info,  Node: Examples<4>,  Next: Recipes<2>,  Prev: Notes on Reproducibility,  Up: random — Generate pseudo-random numbers

5.9.6.9 Examples
................

Basic examples:

     >>> random()                          # Random float:  0.0 <= x < 1.0
     0.37444887175646646

     >>> uniform(2.5, 10.0)                # Random float:  2.5 <= x <= 10.0
     3.1800146073117523

     >>> expovariate(1 / 5)                # Interval between arrivals averaging 5 seconds
     5.148957571865031

     >>> randrange(10)                     # Integer from 0 to 9 inclusive
     7

     >>> randrange(0, 101, 2)              # Even integer from 0 to 100 inclusive
     26

     >>> choice(['win', 'lose', 'draw'])   # Single random element from a sequence
     'draw'

     >>> deck = 'ace two three four'.split()
     >>> shuffle(deck)                     # Shuffle a list
     >>> deck
     ['four', 'two', 'ace', 'three']

     >>> sample([10, 20, 30, 40, 50], k=4) # Four samples without replacement
     [40, 10, 50, 30]

Simulations:

     >>> # Six roulette wheel spins (weighted sampling with replacement)
     >>> choices(['red', 'black', 'green'], [18, 18, 2], k=6)
     ['red', 'green', 'black', 'black', 'red', 'black']

     >>> # Deal 20 cards without replacement from a deck
     >>> # of 52 playing cards, and determine the proportion of cards
     >>> # with a ten-value:  ten, jack, queen, or king.
     >>> deal = sample(['tens', 'low cards'], counts=[16, 36], k=20)
     >>> deal.count('tens') / 20
     0.15

     >>> # Estimate the probability of getting 5 or more heads from 7 spins
     >>> # of a biased coin that settles on heads 60% of the time.
     >>> sum(binomialvariate(n=7, p=0.6) >= 5 for i in range(10_000)) / 10_000
     0.4169

     >>> # Probability of the median of 5 samples being in middle two quartiles
     >>> def trial():
     ...     return 2_500 <= sorted(choices(range(10_000), k=5))[2] < 7_500
     ...
     >>> sum(trial() for i in range(10_000)) / 10_000
     0.7958

Example of statistical bootstrapping(1) using resampling with
replacement to estimate a confidence interval for the mean of a sample:

     # https://www.thoughtco.com/example-of-bootstrapping-3126155
     from statistics import fmean as mean
     from random import choices

     data = [41, 50, 29, 37, 81, 30, 73, 63, 20, 35, 68, 22, 60, 31, 95]
     means = sorted(mean(choices(data, k=len(data))) for i in range(100))
     print(f'The sample mean of {mean(data):.1f} has a 90% confidence '
           f'interval from {means[5]:.1f} to {means[94]:.1f}')

Example of a resampling permutation test(2) to determine the statistical
significance or p-value(3) of an observed difference between the effects
of a drug versus a placebo:

     # Example from "Statistics is Easy" by Dennis Shasha and Manda Wilson
     from statistics import fmean as mean
     from random import shuffle

     drug = [54, 73, 53, 70, 73, 68, 52, 65, 65]
     placebo = [54, 51, 58, 44, 55, 52, 42, 47, 58, 46]
     observed_diff = mean(drug) - mean(placebo)

     n = 10_000
     count = 0
     combined = drug + placebo
     for i in range(n):
         shuffle(combined)
         new_diff = mean(combined[:len(drug)]) - mean(combined[len(drug):])
         count += (new_diff >= observed_diff)

     print(f'{n} label reshufflings produced only {count} instances with a difference')
     print(f'at least as extreme as the observed difference of {observed_diff:.1f}.')
     print(f'The one-sided p-value of {count / n:.4f} leads us to reject the null')
     print(f'hypothesis that there is no difference between the drug and the placebo.')

Simulation of arrival times and service deliveries for a multiserver
queue:

     from heapq import heapify, heapreplace
     from random import expovariate, gauss
     from statistics import mean, quantiles

     average_arrival_interval = 5.6
     average_service_time = 15.0
     stdev_service_time = 3.5
     num_servers = 3

     waits = []
     arrival_time = 0.0
     servers = [0.0] * num_servers  # time when each server becomes available
     heapify(servers)
     for i in range(1_000_000):
         arrival_time += expovariate(1.0 / average_arrival_interval)
         next_server_available = servers[0]
         wait = max(0.0, next_server_available - arrival_time)
         waits.append(wait)
         service_duration = max(0.0, gauss(average_service_time, stdev_service_time))
         service_completed = arrival_time + wait + service_duration
         heapreplace(servers, service_completed)

     print(f'Mean wait: {mean(waits):.1f}   Max wait: {max(waits):.1f}')
     print('Quartiles:', [round(q, 1) for q in quantiles(waits)])

See also
........

Statistics for Hackers(4) a video tutorial by Jake Vanderplas(5) on
statistical analysis using just a few fundamental concepts including
simulation, sampling, shuffling, and cross-validation.

Economics Simulation(6) a simulation of a marketplace by Peter Norvig(7)
that shows effective use of many of the tools and distributions provided
by this module (gauss, uniform, sample, betavariate, choice, triangular,
and randrange).

A Concrete Introduction to Probability (using Python)(8) a tutorial by
Peter Norvig(9) covering the basics of probability theory, how to write
simulations, and how to perform data analysis using Python.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Bootstrapping_(statistics)

   (2) 
https://en.wikipedia.org/wiki/Resampling_(statistics)#Permutation_tests

   (3) https://en.wikipedia.org/wiki/P-value

   (4) https://www.youtube.com/watch?v=Iq9DzN6mvYA

   (5) https://us.pycon.org/2016/speaker/profile/295/

   (6) https://nbviewer.org/url/norvig.com/ipython/Economics.ipynb

   (7) https://norvig.com/bio.html

   (8) https://nbviewer.org/url/norvig.com/ipython/Probability.ipynb

   (9) https://norvig.com/bio.html


File: python.info,  Node: Recipes<2>,  Next: Command-line usage,  Prev: Examples<4>,  Up: random — Generate pseudo-random numbers

5.9.6.10 Recipes
................

These recipes show how to efficiently make random selections from the
combinatoric iterators in the *note itertools: 81. module:

     import random

     def random_product(*iterables, repeat=1):
         "Random selection from itertools.product(*iterables, repeat=repeat)"
         pools = tuple(map(tuple, iterables)) * repeat
         return tuple(map(random.choice, pools))

     def random_permutation(iterable, r=None):
         "Random selection from itertools.permutations(iterable, r)"
         pool = tuple(iterable)
         r = len(pool) if r is None else r
         return tuple(random.sample(pool, r))

     def random_combination(iterable, r):
         "Random selection from itertools.combinations(iterable, r)"
         pool = tuple(iterable)
         n = len(pool)
         indices = sorted(random.sample(range(n), r))
         return tuple(pool[i] for i in indices)

     def random_combination_with_replacement(iterable, r):
         "Choose r elements with replacement.  Order the result to match the iterable."
         # Result will be in set(itertools.combinations_with_replacement(iterable, r)).
         pool = tuple(iterable)
         n = len(pool)
         indices = sorted(random.choices(range(n), k=r))
         return tuple(pool[i] for i in indices)

     def random_derangement(iterable):
         "Choose a permutation where no element stays in its original position."
         seq = tuple(iterable)
         if len(seq) < 2:
             if not seq:
                 return ()
             raise IndexError('No derangments to choose from')
         perm = list(range(len(seq)))
         start = tuple(perm)
         while True:
             random.shuffle(perm)
             if all(p != q for p, q in zip(start, perm)):
                 return tuple([seq[i] for i in perm])

The default *note random(): 74b. returns multiples of 2⁻⁵³ in the range
'0.0 ≤ x < 1.0'.  All such numbers are evenly spaced and are exactly
representable as Python floats.  However, many other representable
floats in that interval are not possible selections.  For example,
‘0.05954861408025609’ isn’t an integer multiple of 2⁻⁵³.

The following recipe takes a different approach.  All floats in the
interval are possible selections.  The mantissa comes from a uniform
distribution of integers in the range '2⁵² ≤ mantissa < 2⁵³'.  The
exponent comes from a geometric distribution where exponents smaller
than '-53' occur half as often as the next larger exponent.

     from random import Random
     from math import ldexp

     class FullRandom(Random):

         def random(self):
             mantissa = 0x10_0000_0000_0000 | self.getrandbits(52)
             exponent = -53
             x = 0
             while not x:
                 x = self.getrandbits(32)
                 exponent += x.bit_length() - 32
             return ldexp(mantissa, exponent)

All *note real valued distributions: 28b4. in the class will use the new
method:

     >>> fr = FullRandom()
     >>> fr.random()
     0.05954861408025609
     >>> fr.expovariate(0.25)
     8.87925541791544

The recipe is conceptually equivalent to an algorithm that chooses from
all the multiples of 2⁻¹⁰⁷⁴ in the range '0.0 ≤ x < 1.0'.  All such
numbers are evenly spaced, but most have to be rounded down to the
nearest representable Python float.  (The value 2⁻¹⁰⁷⁴ is the smallest
positive unnormalized float and is equal to ‘math.ulp(0.0)’.)

See also
........

Generating Pseudo-random Floating-Point Values(1) a paper by Allen B.
Downey describing ways to generate more fine-grained floats than
normally generated by *note random(): 74b.

   ---------- Footnotes ----------

   (1) https://allendowney.com/research/rand/downey07randfloat.pdf


File: python.info,  Node: Command-line usage,  Next: Command-line example,  Prev: Recipes<2>,  Up: random — Generate pseudo-random numbers

5.9.6.11 Command-line usage
...........................

Added in version 3.13.

The ‘random’ module can be executed from the command line.

     python -m random [-h] [-c CHOICE [CHOICE ...] | -i N | -f N] [input ...]

The following options are accepted:

 -- Option: -h, --help

     Show the help message and exit.

 -- Option: -c CHOICE [CHOICE ...]
 -- Option: --choice CHOICE [CHOICE ...]

     Print a random choice, using *note choice(): 1276.

 -- Option: -i <N>
 -- Option: --integer <N>

     Print a random integer between 1 and N inclusive, using *note
     randint(): 1275.

 -- Option: -f <N>
 -- Option: --float <N>

     Print a random floating-point number between 0 and N inclusive,
     using *note uniform(): 28b5.

If no options are given, the output depends on the input:

   * String or multiple: same as *note -choice: 28c9.

   * Integer: same as *note -integer: 28cb.

   * Float: same as *note -float: 28cd.


File: python.info,  Node: Command-line example,  Prev: Command-line usage,  Up: random — Generate pseudo-random numbers

5.9.6.12 Command-line example
.............................

Here are some examples of the ‘random’ command-line interface:

     $ # Choose one at random
     $ python -m random egg bacon sausage spam "Lobster Thermidor aux crevettes with a Mornay sauce"
     Lobster Thermidor aux crevettes with a Mornay sauce

     $ # Random integer
     $ python -m random 6
     6

     $ # Random floating-point number
     $ python -m random 1.8
     1.7080016272295635

     $ # With explicit arguments
     $ python  -m random --choice egg bacon sausage spam "Lobster Thermidor aux crevettes with a Mornay sauce"
     egg

     $ python -m random --integer 6
     3

     $ python -m random --float 1.8
     1.5666339105010318

     $ python -m random --integer 6
     5

     $ python -m random --float 6
     3.1942323316565915


File: python.info,  Node: statistics — Mathematical statistics functions,  Prev: random — Generate pseudo-random numbers,  Up: Numeric and Mathematical Modules

5.9.7 ‘statistics’ — Mathematical statistics functions
------------------------------------------------------

Added in version 3.4.

'Source code:' Lib/statistics.py(1)

__________________________________________________________________

This module provides functions for calculating mathematical statistics
of numeric (*note Real: 234e.-valued) data.

The module is not intended to be a competitor to third-party libraries
such as NumPy(2), SciPy(3), or proprietary full-featured statistics
packages aimed at professional statisticians such as Minitab, SAS and
Matlab.  It is aimed at the level of graphing and scientific
calculators.

Unless explicitly noted, these functions support *note int: 257, *note
float: 2f7, *note Decimal: 29d. and *note Fraction: 1e7.  Behaviour with
other types (whether in the numeric tower or not) is currently
unsupported.  Collections with a mix of types are also undefined and
implementation-dependent.  If your input data consists of mixed types,
you may be able to use *note map(): 86a. to ensure a consistent result,
for example: ‘map(float, input_data)’.

Some datasets use ‘NaN’ (not a number) values to represent missing data.
Since NaNs have unusual comparison semantics, they cause surprising or
undefined behaviors in the statistics functions that sort data or that
count occurrences.  The functions affected are ‘median()’,
‘median_low()’, ‘median_high()’, ‘median_grouped()’, ‘mode()’,
‘multimode()’, and ‘quantiles()’.  The ‘NaN’ values should be stripped
before calling these functions:

     >>> from statistics import median
     >>> from math import isnan
     >>> from itertools import filterfalse

     >>> data = [20.7, float('NaN'),19.2, 18.3, float('NaN'), 14.4]
     >>> sorted(data)  # This has surprising behavior
     [20.7, nan, 14.4, 18.3, 19.2, nan]
     >>> median(data)  # This result is unexpected
     16.35

     >>> sum(map(isnan, data))    # Number of missing values
     2
     >>> clean = list(filterfalse(isnan, data))  # Strip NaN values
     >>> clean
     [20.7, 19.2, 18.3, 14.4]
     >>> sorted(clean)  # Sorting now works as expected
     [14.4, 18.3, 19.2, 20.7]
     >>> median(clean)       # This result is now well defined
     18.75

* Menu:

* Averages and measures of central location::
* Measures of spread::
* Statistics for relations between two inputs::
* Function details::
* Exceptions: Exceptions<5>.
* NormalDist objects::
* Examples and Recipes: Examples and Recipes<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/statistics.py

   (2) https://numpy.org

   (3) https://scipy.org/


File: python.info,  Node: Averages and measures of central location,  Next: Measures of spread,  Up: statistics — Mathematical statistics functions

5.9.7.1 Averages and measures of central location
.................................................

These functions calculate an average or typical value from a population
or sample.

*note mean(): 6d5.          Arithmetic mean (“average”) of data.
                            
                            
*note fmean(): a41.         Fast, floating-point arithmetic mean, with optional weighting.
                            
                            
*note geometric_mean(): a42.Geometric mean of data.
                            
                            
*note harmonic_mean(): d08. Harmonic mean of data.
                            
                            
*note kde(): 24a.           Estimate the probability density distribution of the data.
                            
                            
*note kde_random(): 24b.    Random sampling from the PDF generated by kde().
                            
                            
*note median(): 28d4.       Median (middle value) of data.
                            
                            
*note median_low(): 28d5.   Low median of data.
                            
                            
*note median_high(): 28d6.  High median of data.
                            
                            
*note median_grouped(): 28d7.Median (50th percentile) of grouped data.
                            
                            
*note mode(): aa3.          Single mode (most common value) of discrete or nominal data.
                            
                            
*note multimode(): a43.     List of modes (most common values) of discrete or nominal data.
                            
                            
*note quantiles(): a44.     Divide data into intervals with equal probability.
                            


File: python.info,  Node: Measures of spread,  Next: Statistics for relations between two inputs,  Prev: Averages and measures of central location,  Up: statistics — Mathematical statistics functions

5.9.7.2 Measures of spread
..........................

These functions calculate a measure of how much the population or sample
tends to deviate from the typical or average values.

*note pstdev(): 15f8.       Population standard deviation of data.
                            
                            
*note pvariance(): 28d9.    Population variance of data.
                            
                            
*note stdev(): 6d7.         Sample standard deviation of data.
                            
                            
*note variance(): 6d6.      Sample variance of data.
                            


File: python.info,  Node: Statistics for relations between two inputs,  Next: Function details,  Prev: Measures of spread,  Up: statistics — Mathematical statistics functions

5.9.7.3 Statistics for relations between two inputs
...................................................

These functions calculate statistics regarding relations between two
inputs.

*note covariance(): 836.      Sample covariance for two variables.
                              
                              
*note correlation(): 4bf.     Pearson and Spearman’s correlation coefficients.
                              
                              
*note linear_regression(): 837.Slope and intercept for simple linear regression.
                              


File: python.info,  Node: Function details,  Next: Exceptions<5>,  Prev: Statistics for relations between two inputs,  Up: statistics — Mathematical statistics functions

5.9.7.4 Function details
........................

Note: The functions do not require the data given to them to be sorted.
However, for reading convenience, most of the examples show sorted
sequences.

 -- Function: statistics.mean (data)

     Return the sample arithmetic mean of 'data' which can be a sequence
     or iterable.

     The arithmetic mean is the sum of the data divided by the number of
     data points.  It is commonly called “the average”, although it is
     only one of many different mathematical averages.  It is a measure
     of the central location of the data.

     If 'data' is empty, *note StatisticsError: 28dc. will be raised.

     Some examples of use:

          >>> mean([1, 2, 3, 4, 4])
          2.8
          >>> mean([-1.0, 2.5, 3.25, 5.75])
          2.625

          >>> from fractions import Fraction as F
          >>> mean([F(3, 7), F(1, 21), F(5, 3), F(1, 3)])
          Fraction(13, 21)

          >>> from decimal import Decimal as D
          >>> mean([D("0.5"), D("0.75"), D("0.625"), D("0.375")])
          Decimal('0.5625')

          Note: The mean is strongly affected by outliers(1) and is not
          necessarily a typical example of the data points.  For a more
          robust, although less efficient, measure of central
          tendency(2), see *note median(): 28d4.

          The sample mean gives an unbiased estimate of the true
          population mean, so that when taken on average over all the
          possible samples, ‘mean(sample)’ converges on the true mean of
          the entire population.  If 'data' represents the entire
          population rather than a sample, then ‘mean(data)’ is
          equivalent to calculating the true population mean μ.

 -- Function: statistics.fmean (data, weights=None)

     Convert 'data' to floats and compute the arithmetic mean.

     This runs faster than the *note mean(): 6d5. function and it always
     returns a *note float: 2f7.  The 'data' may be a sequence or
     iterable.  If the input dataset is empty, raises a *note
     StatisticsError: 28dc.

          >>> fmean([3.5, 4.0, 5.25])
          4.25

     Optional weighting is supported.  For example, a professor assigns
     a grade for a course by weighting quizzes at 20%, homework at 20%,
     a midterm exam at 30%, and a final exam at 30%:

          >>> grades = [85, 92, 83, 91]
          >>> weights = [0.20, 0.20, 0.30, 0.30]
          >>> fmean(grades, weights)
          87.6

     If 'weights' is supplied, it must be the same length as the 'data'
     or a *note ValueError: 202. will be raised.

     Added in version 3.8.

     Changed in version 3.11: Added support for 'weights'.

 -- Function: statistics.geometric_mean (data)

     Convert 'data' to floats and compute the geometric mean.

     The geometric mean indicates the central tendency or typical value
     of the 'data' using the product of the values (as opposed to the
     arithmetic mean which uses their sum).

     Raises a *note StatisticsError: 28dc. if the input dataset is
     empty, if it contains a zero, or if it contains a negative value.
     The 'data' may be a sequence or iterable.

     No special efforts are made to achieve exact results.  (However,
     this may change in the future.)

          >>> round(geometric_mean([54, 24, 36]), 1)
          36.0

     Added in version 3.8.

 -- Function: statistics.harmonic_mean (data, weights=None)

     Return the harmonic mean of 'data', a sequence or iterable of
     real-valued numbers.  If 'weights' is omitted or ‘None’, then equal
     weighting is assumed.

     The harmonic mean is the reciprocal of the arithmetic *note mean():
     6d5. of the reciprocals of the data.  For example, the harmonic
     mean of three values 'a', 'b' and 'c' will be equivalent to ‘3/(1/a
     + 1/b + 1/c)’.  If one of the values is zero, the result will be
     zero.

     The harmonic mean is a type of average, a measure of the central
     location of the data.  It is often appropriate when averaging
     ratios or rates, for example speeds.

     Suppose a car travels 10 km at 40 km/hr, then another 10 km at 60
     km/hr.  What is the average speed?

          >>> harmonic_mean([40, 60])
          48.0

     Suppose a car travels 40 km/hr for 5 km, and when traffic clears,
     speeds-up to 60 km/hr for the remaining 30 km of the journey.  What
     is the average speed?

          >>> harmonic_mean([40, 60], weights=[5, 30])
          56.0

     *note StatisticsError: 28dc. is raised if 'data' is empty, any
     element is less than zero, or if the weighted sum isn’t positive.

     The current algorithm has an early-out when it encounters a zero in
     the input.  This means that the subsequent inputs are not tested
     for validity.  (This behavior may change in the future.)

     Added in version 3.6.

     Changed in version 3.10: Added support for 'weights'.

 -- Function: statistics.kde (data, h, kernel='normal', *,
          cumulative=False)

     Kernel Density Estimation (KDE)(3): Create a continuous probability
     density function or cumulative distribution function from discrete
     samples.

     The basic idea is to smooth the data using a kernel function(4).
     to help draw inferences about a population from a sample.

     The degree of smoothing is controlled by the scaling parameter 'h'
     which is called the bandwidth.  Smaller values emphasize local
     features while larger values give smoother results.

     The 'kernel' determines the relative weights of the sample data
     points.  Generally, the choice of kernel shape does not matter as
     much as the more influential bandwidth smoothing parameter.

     Kernels that give some weight to every sample point include
     'normal' ('gauss'), 'logistic', and 'sigmoid'.

     Kernels that only give weight to sample points within the bandwidth
     include 'rectangular' ('uniform'), 'triangular', 'parabolic'
     ('epanechnikov'), 'quartic' ('biweight'), 'triweight', and
     'cosine'.

     If 'cumulative' is true, will return a cumulative distribution
     function.

     A *note StatisticsError: 28dc. will be raised if the 'data'
     sequence is empty.

     Wikipedia has an example(5) where we can use ‘kde()’ to generate
     and plot a probability density function estimated from a small
     sample:

          >>> sample = [-2.1, -1.3, -0.4, 1.9, 5.1, 6.2]
          >>> f_hat = kde(sample, h=1.5)
          >>> xarr = [i/100 for i in range(-750, 1100)]
          >>> yarr = [f_hat(x) for x in xarr]

     The points in ‘xarr’ and ‘yarr’ can be used to make a PDF plot:

[image src="python-figures/kde_example.png" alt="Scatter plot of the estimated probability density function."]


     Added in version 3.13.

 -- Function: statistics.kde_random (data, h, kernel='normal', *,
          seed=None)

     Return a function that makes a random selection from the estimated
     probability density function produced by ‘kde(data, h, kernel)’.

     Providing a 'seed' allows reproducible selections.  In the future,
     the values may change slightly as more accurate kernel inverse CDF
     estimates are implemented.  The seed may be an integer, float, str,
     or bytes.

     A *note StatisticsError: 28dc. will be raised if the 'data'
     sequence is empty.

     Continuing the example for *note kde(): 24a, we can use
     ‘kde_random()’ to generate new random selections from an estimated
     probability density function:

          >>> data = [-2.1, -1.3, -0.4, 1.9, 5.1, 6.2]
          >>> rand = kde_random(data, h=1.5, seed=8675309)
          >>> new_selections = [rand() for i in range(10)]
          >>> [round(x, 1) for x in new_selections]
          [0.7, 6.2, 1.2, 6.9, 7.0, 1.8, 2.5, -0.5, -1.8, 5.6]

     Added in version 3.13.

 -- Function: statistics.median (data)

     Return the median (middle value) of numeric data, using the common
     “mean of middle two” method.  If 'data' is empty, *note
     StatisticsError: 28dc. is raised.  'data' can be a sequence or
     iterable.

     The median is a robust measure of central location and is less
     affected by the presence of outliers.  When the number of data
     points is odd, the middle data point is returned:

          >>> median([1, 3, 5])
          3

     When the number of data points is even, the median is interpolated
     by taking the average of the two middle values:

          >>> median([1, 3, 5, 7])
          4.0

     This is suited for when your data is discrete, and you don’t mind
     that the median may not be an actual data point.

     If the data is ordinal (supports order operations) but not numeric
     (doesn’t support addition), consider using *note median_low():
     28d5. or *note median_high(): 28d6. instead.

 -- Function: statistics.median_low (data)

     Return the low median of numeric data.  If 'data' is empty, *note
     StatisticsError: 28dc. is raised.  'data' can be a sequence or
     iterable.

     The low median is always a member of the data set.  When the number
     of data points is odd, the middle value is returned.  When it is
     even, the smaller of the two middle values is returned.

          >>> median_low([1, 3, 5])
          3
          >>> median_low([1, 3, 5, 7])
          3

     Use the low median when your data are discrete and you prefer the
     median to be an actual data point rather than interpolated.

 -- Function: statistics.median_high (data)

     Return the high median of data.  If 'data' is empty, *note
     StatisticsError: 28dc. is raised.  'data' can be a sequence or
     iterable.

     The high median is always a member of the data set.  When the
     number of data points is odd, the middle value is returned.  When
     it is even, the larger of the two middle values is returned.

          >>> median_high([1, 3, 5])
          3
          >>> median_high([1, 3, 5, 7])
          5

     Use the high median when your data are discrete and you prefer the
     median to be an actual data point rather than interpolated.

 -- Function: statistics.median_grouped (data, interval=1.0)

     Estimates the median for numeric data that has been grouped or
     binned(6) around the midpoints of consecutive, fixed-width
     intervals.

     The 'data' can be any iterable of numeric data with each value
     being exactly the midpoint of a bin.  At least one value must be
     present.

     The 'interval' is the width of each bin.

     For example, demographic information may have been summarized into
     consecutive ten-year age groups with each group being represented
     by the 5-year midpoints of the intervals:

          >>> from collections import Counter
          >>> demographics = Counter({
          ...    25: 172,   # 20 to 30 years old
          ...    35: 484,   # 30 to 40 years old
          ...    45: 387,   # 40 to 50 years old
          ...    55:  22,   # 50 to 60 years old
          ...    65:   6,   # 60 to 70 years old
          ... })
          ...

     The 50th percentile (median) is the 536th person out of the 1071
     member cohort.  That person is in the 30 to 40 year old age group.

     The regular *note median(): 28d4. function would assume that
     everyone in the tricenarian age group was exactly 35 years old.  A
     more tenable assumption is that the 484 members of that age group
     are evenly distributed between 30 and 40.  For that, we use
     ‘median_grouped()’:

          >>> data = list(demographics.elements())
          >>> median(data)
          35
          >>> round(median_grouped(data, interval=10), 1)
          37.5

     The caller is responsible for making sure the data points are
     separated by exact multiples of 'interval'.  This is essential for
     getting a correct result.  The function does not check this
     precondition.

     Inputs may be any numeric type that can be coerced to a float
     during the interpolation step.

 -- Function: statistics.mode (data)

     Return the single most common data point from discrete or nominal
     'data'.  The mode (when it exists) is the most typical value and
     serves as a measure of central location.

     If there are multiple modes with the same frequency, returns the
     first one encountered in the 'data'.  If the smallest or largest of
     those is desired instead, use ‘min(multimode(data))’ or
     ‘max(multimode(data))’.  If the input 'data' is empty, *note
     StatisticsError: 28dc. is raised.

     ‘mode’ assumes discrete data and returns a single value.  This is
     the standard treatment of the mode as commonly taught in schools:

          >>> mode([1, 1, 2, 3, 3, 3, 3, 4])
          3

     The mode is unique in that it is the only statistic in this package
     that also applies to nominal (non-numeric) data:

          >>> mode(["red", "blue", "blue", "red", "green", "red", "red"])
          'red'

     Only hashable inputs are supported.  To handle type *note set: 5dc,
     consider casting to *note frozenset: 5dd.  To handle type *note
     list: 614, consider casting to *note tuple: 373.  For mixed or
     nested inputs, consider using this slower quadratic algorithm that
     only depends on equality tests: ‘max(data, key=data.count)’.

     Changed in version 3.8: Now handles multimodal datasets by
     returning the first mode encountered.  Formerly, it raised *note
     StatisticsError: 28dc. when more than one mode was found.

 -- Function: statistics.multimode (data)

     Return a list of the most frequently occurring values in the order
     they were first encountered in the 'data'.  Will return more than
     one result if there are multiple modes or an empty list if the
     'data' is empty:

          >>> multimode('aabbbbccddddeeffffgg')
          ['b', 'd', 'f']
          >>> multimode('')
          []

     Added in version 3.8.

 -- Function: statistics.pstdev (data, mu=None)

     Return the population standard deviation (the square root of the
     population variance).  See *note pvariance(): 28d9. for arguments
     and other details.

          >>> pstdev([1.5, 2.5, 2.5, 2.75, 3.25, 4.75])
          0.986893273527251

 -- Function: statistics.pvariance (data, mu=None)

     Return the population variance of 'data', a non-empty sequence or
     iterable of real-valued numbers.  Variance, or second moment about
     the mean, is a measure of the variability (spread or dispersion) of
     data.  A large variance indicates that the data is spread out; a
     small variance indicates it is clustered closely around the mean.

     If the optional second argument 'mu' is given, it should be the
     'population' mean of the 'data'.  It can also be used to compute
     the second moment around a point that is not the mean.  If it is
     missing or ‘None’ (the default), the arithmetic mean is
     automatically calculated.

     Use this function to calculate the variance from the entire
     population.  To estimate the variance from a sample, the *note
     variance(): 6d6. function is usually a better choice.

     Raises *note StatisticsError: 28dc. if 'data' is empty.

     Examples:

          >>> data = [0.0, 0.25, 0.25, 1.25, 1.5, 1.75, 2.75, 3.25]
          >>> pvariance(data)
          1.25

     If you have already calculated the mean of your data, you can pass
     it as the optional second argument 'mu' to avoid recalculation:

          >>> mu = mean(data)
          >>> pvariance(data, mu)
          1.25

     Decimals and Fractions are supported:

          >>> from decimal import Decimal as D
          >>> pvariance([D("27.5"), D("30.25"), D("30.25"), D("34.5"), D("41.75")])
          Decimal('24.815')

          >>> from fractions import Fraction as F
          >>> pvariance([F(1, 4), F(5, 4), F(1, 2)])
          Fraction(13, 72)

          Note: When called with the entire population, this gives the
          population variance σ².  When called on a sample instead, this
          is the biased sample variance s², also known as variance with
          N degrees of freedom.

          If you somehow know the true population mean μ, you may use
          this function to calculate the variance of a sample, giving
          the known population mean as the second argument.  Provided
          the data points are a random sample of the population, the
          result will be an unbiased estimate of the population
          variance.

 -- Function: statistics.stdev (data, xbar=None)

     Return the sample standard deviation (the square root of the sample
     variance).  See *note variance(): 6d6. for arguments and other
     details.

          >>> stdev([1.5, 2.5, 2.5, 2.75, 3.25, 4.75])
          1.0810874155219827

 -- Function: statistics.variance (data, xbar=None)

     Return the sample variance of 'data', an iterable of at least two
     real-valued numbers.  Variance, or second moment about the mean, is
     a measure of the variability (spread or dispersion) of data.  A
     large variance indicates that the data is spread out; a small
     variance indicates it is clustered closely around the mean.

     If the optional second argument 'xbar' is given, it should be the
     'sample' mean of 'data'.  If it is missing or ‘None’ (the default),
     the mean is automatically calculated.

     Use this function when your data is a sample from a population.  To
     calculate the variance from the entire population, see *note
     pvariance(): 28d9.

     Raises *note StatisticsError: 28dc. if 'data' has fewer than two
     values.

     Examples:

          >>> data = [2.75, 1.75, 1.25, 0.25, 0.5, 1.25, 3.5]
          >>> variance(data)
          1.3720238095238095

     If you have already calculated the sample mean of your data, you
     can pass it as the optional second argument 'xbar' to avoid
     recalculation:

          >>> m = mean(data)
          >>> variance(data, m)
          1.3720238095238095

     This function does not attempt to verify that you have passed the
     actual mean as 'xbar'.  Using arbitrary values for 'xbar' can lead
     to invalid or impossible results.

     Decimal and Fraction values are supported:

          >>> from decimal import Decimal as D
          >>> variance([D("27.5"), D("30.25"), D("30.25"), D("34.5"), D("41.75")])
          Decimal('31.01875')

          >>> from fractions import Fraction as F
          >>> variance([F(1, 6), F(1, 2), F(5, 3)])
          Fraction(67, 108)

          Note: This is the sample variance s² with Bessel’s correction,
          also known as variance with N-1 degrees of freedom.  Provided
          that the data points are representative (e.g.  independent and
          identically distributed), the result should be an unbiased
          estimate of the true population variance.

          If you somehow know the actual population mean μ you should
          pass it to the *note pvariance(): 28d9. function as the 'mu'
          parameter to get the variance of a sample.

 -- Function: statistics.quantiles (data, *, n=4, method='exclusive')

     Divide 'data' into 'n' continuous intervals with equal probability.
     Returns a list of ‘n - 1’ cut points separating the intervals.

     Set 'n' to 4 for quartiles (the default).  Set 'n' to 10 for
     deciles.  Set 'n' to 100 for percentiles which gives the 99 cuts
     points that separate 'data' into 100 equal sized groups.  Raises
     *note StatisticsError: 28dc. if 'n' is not least 1.

     The 'data' can be any iterable containing sample data.  For
     meaningful results, the number of data points in 'data' should be
     larger than 'n'.  Raises *note StatisticsError: 28dc. if there is
     not at least one data point.

     The cut points are linearly interpolated from the two nearest data
     points.  For example, if a cut point falls one-third of the
     distance between two sample values, ‘100’ and ‘112’, the cut-point
     will evaluate to ‘104’.

     The 'method' for computing quantiles can be varied depending on
     whether the 'data' includes or excludes the lowest and highest
     possible values from the population.

     The default 'method' is “exclusive” and is used for data sampled
     from a population that can have more extreme values than found in
     the samples.  The portion of the population falling below the
     'i-th' of 'm' sorted data points is computed as ‘i / (m + 1)’.
     Given nine sample values, the method sorts them and assigns the
     following percentiles: 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%.

     Setting the 'method' to “inclusive” is used for describing
     population data or for samples that are known to include the most
     extreme values from the population.  The minimum value in 'data' is
     treated as the 0th percentile and the maximum value is treated as
     the 100th percentile.  The portion of the population falling below
     the 'i-th' of 'm' sorted data points is computed as ‘(i - 1) / (m -
     1)’.  Given 11 sample values, the method sorts them and assigns the
     following percentiles: 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%,
     90%, 100%.

          # Decile cut points for empirically sampled data
          >>> data = [105, 129, 87, 86, 111, 111, 89, 81, 108, 92, 110,
          ...         100, 75, 105, 103, 109, 76, 119, 99, 91, 103, 129,
          ...         106, 101, 84, 111, 74, 87, 86, 103, 103, 106, 86,
          ...         111, 75, 87, 102, 121, 111, 88, 89, 101, 106, 95,
          ...         103, 107, 101, 81, 109, 104]
          >>> [round(q, 1) for q in quantiles(data, n=10)]
          [81.0, 86.2, 89.0, 99.4, 102.5, 103.6, 106.0, 109.8, 111.0]

     Added in version 3.8.

     Changed in version 3.13: No longer raises an exception for an input
     with only a single data point.  This allows quantile estimates to
     be built up one sample point at a time becoming gradually more
     refined with each new data point.

 -- Function: statistics.covariance (x, y, /)

     Return the sample covariance of two inputs 'x' and 'y'.  Covariance
     is a measure of the joint variability of two inputs.

     Both inputs must be of the same length (no less than two),
     otherwise *note StatisticsError: 28dc. is raised.

     Examples:

          >>> x = [1, 2, 3, 4, 5, 6, 7, 8, 9]
          >>> y = [1, 2, 3, 1, 2, 3, 1, 2, 3]
          >>> covariance(x, y)
          0.75
          >>> z = [9, 8, 7, 6, 5, 4, 3, 2, 1]
          >>> covariance(x, z)
          -7.5
          >>> covariance(z, x)
          -7.5

     Added in version 3.10.

 -- Function: statistics.correlation (x, y, /, *, method='linear')

     Return the Pearson's correlation coefficient(7) for two inputs.
     Pearson’s correlation coefficient 'r' takes values between -1 and
     +1.  It measures the strength and direction of a linear
     relationship.

     If 'method' is “ranked”, computes Spearman's rank correlation
     coefficient(8) for two inputs.  The data is replaced by ranks.
     Ties are averaged so that equal values receive the same rank.  The
     resulting coefficient measures the strength of a monotonic
     relationship.

     Spearman’s correlation coefficient is appropriate for ordinal data
     or for continuous data that doesn’t meet the linear proportion
     requirement for Pearson’s correlation coefficient.

     Both inputs must be of the same length (no less than two), and need
     not to be constant, otherwise *note StatisticsError: 28dc. is
     raised.

     Example with Kepler's laws of planetary motion(9):

          >>> # Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and  Neptune
          >>> orbital_period = [88, 225, 365, 687, 4331, 10_756, 30_687, 60_190]    # days
          >>> dist_from_sun = [58, 108, 150, 228, 778, 1_400, 2_900, 4_500] # million km

          >>> # Show that a perfect monotonic relationship exists
          >>> correlation(orbital_period, dist_from_sun, method='ranked')
          1.0

          >>> # Observe that a linear relationship is imperfect
          >>> round(correlation(orbital_period, dist_from_sun), 4)
          0.9882

          >>> # Demonstrate Kepler's third law: There is a linear correlation
          >>> # between the square of the orbital period and the cube of the
          >>> # distance from the sun.
          >>> period_squared = [p * p for p in orbital_period]
          >>> dist_cubed = [d * d * d for d in dist_from_sun]
          >>> round(correlation(period_squared, dist_cubed), 4)
          1.0

     Added in version 3.10.

     Changed in version 3.12: Added support for Spearman’s rank
     correlation coefficient.

 -- Function: statistics.linear_regression (x, y, /, *,
          proportional=False)

     Return the slope and intercept of simple linear regression(10)
     parameters estimated using ordinary least squares.  Simple linear
     regression describes the relationship between an independent
     variable 'x' and a dependent variable 'y' in terms of this linear
     function:

          'y = slope * x + intercept + noise'

     where ‘slope’ and ‘intercept’ are the regression parameters that
     are estimated, and ‘noise’ represents the variability of the data
     that was not explained by the linear regression (it is equal to the
     difference between predicted and actual values of the dependent
     variable).

     Both inputs must be of the same length (no less than two), and the
     independent variable 'x' cannot be constant; otherwise a *note
     StatisticsError: 28dc. is raised.

     For example, we can use the release dates of the Monty Python
     films(11) to predict the cumulative number of Monty Python films
     that would have been produced by 2019 assuming that they had kept
     the pace.

          >>> year = [1971, 1975, 1979, 1982, 1983]
          >>> films_total = [1, 2, 3, 4, 5]
          >>> slope, intercept = linear_regression(year, films_total)
          >>> round(slope * 2019 + intercept)
          16

     If 'proportional' is true, the independent variable 'x' and the
     dependent variable 'y' are assumed to be directly proportional.
     The data is fit to a line passing through the origin.  Since the
     'intercept' will always be 0.0, the underlying linear function
     simplifies to:

          'y = slope * x + noise'

     Continuing the example from *note correlation(): 4bf, we look to
     see how well a model based on major planets can predict the orbital
     distances for dwarf planets:

          >>> model = linear_regression(period_squared, dist_cubed, proportional=True)
          >>> slope = model.slope

          >>> # Dwarf planets:   Pluto,  Eris,    Makemake, Haumea, Ceres
          >>> orbital_periods = [90_560, 204_199, 111_845, 103_410, 1_680]  # days
          >>> predicted_dist = [math.cbrt(slope * (p * p)) for p in orbital_periods]
          >>> list(map(round, predicted_dist))
          [5912, 10166, 6806, 6459, 414]

          >>> [5_906, 10_152, 6_796, 6_450, 414]  # actual distance in million km
          [5906, 10152, 6796, 6450, 414]

     Added in version 3.10.

     Changed in version 3.11: Added support for 'proportional'.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Outlier

   (2) https://en.wikipedia.org/wiki/Central_tendency

   (3) 
https://www.itm-conferences.org/articles/itmconf/pdf/2018/08/itmconf_sam2018_00037.pdf

   (4) https://en.wikipedia.org/wiki/Kernel_(statistics)

   (5) https://en.wikipedia.org/wiki/Kernel_density_estimation#Example

   (6) https://en.wikipedia.org/wiki/Data_binning

   (7) https://en.wikipedia.org/wiki/Pearson_correlation_coefficient

   (8) 
https://en.wikipedia.org/wiki/Spearman%27s_rank_correlation_coefficient

   (9) https://en.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion

   (10) https://en.wikipedia.org/wiki/Simple_linear_regression

   (11) https://en.wikipedia.org/wiki/Monty_Python#Films


File: python.info,  Node: Exceptions<5>,  Next: NormalDist objects,  Prev: Function details,  Up: statistics — Mathematical statistics functions

5.9.7.5 Exceptions
..................

A single exception is defined:

 -- Exception: statistics.StatisticsError

     Subclass of *note ValueError: 202. for statistics-related
     exceptions.


File: python.info,  Node: NormalDist objects,  Next: Examples and Recipes<2>,  Prev: Exceptions<5>,  Up: statistics — Mathematical statistics functions

5.9.7.6 ‘NormalDist’ objects
............................

*note NormalDist: a45. is a tool for creating and manipulating normal
distributions of a random variable(1).  It is a class that treats the
mean and standard deviation of data measurements as a single entity.

Normal distributions arise from the Central Limit Theorem(2) and have a
wide range of applications in statistics.

 -- Class: statistics.NormalDist (mu=0.0, sigma=1.0)

     Returns a new 'NormalDist' object where 'mu' represents the
     arithmetic mean(3) and 'sigma' represents the standard
     deviation(4).

     If 'sigma' is negative, raises *note StatisticsError: 28dc.

      -- Attribute: mean

          A read-only property for the arithmetic mean(5) of a normal
          distribution.

      -- Attribute: median

          A read-only property for the median(6) of a normal
          distribution.

      -- Attribute: mode

          A read-only property for the mode(7) of a normal distribution.

      -- Attribute: stdev

          A read-only property for the standard deviation(8) of a normal
          distribution.

      -- Attribute: variance

          A read-only property for the variance(9) of a normal
          distribution.  Equal to the square of the standard deviation.

      -- Method: classmethod from_samples (data)

          Makes a normal distribution instance with 'mu' and 'sigma'
          parameters estimated from the 'data' using *note fmean(): a41.
          and *note stdev(): 6d7.

          The 'data' can be any *note iterable: 126d. and should consist
          of values that can be converted to type *note float: 2f7.  If
          'data' does not contain at least two elements, raises *note
          StatisticsError: 28dc. because it takes at least one point to
          estimate a central value and at least two points to estimate
          dispersion.

      -- Method: samples (n, *, seed=None)

          Generates 'n' random samples for a given mean and standard
          deviation.  Returns a *note list: 614. of *note float: 2f7.
          values.

          If 'seed' is given, creates a new instance of the underlying
          random number generator.  This is useful for creating
          reproducible results, even in a multi-threading context.

          Changed in version 3.13.

          Switched to a faster algorithm.  To reproduce samples from
          previous versions, use *note random.seed(): 12ba. and *note
          random.gauss(): 197d.

      -- Method: pdf (x)

          Using a probability density function (pdf)(10), compute the
          relative likelihood that a random variable 'X' will be near
          the given value 'x'.  Mathematically, it is the limit of the
          ratio ‘P(x <= X < x+dx) / dx’ as 'dx' approaches zero.

          The relative likelihood is computed as the probability of a
          sample occurring in a narrow range divided by the width of the
          range (hence the word “density”).  Since the likelihood is
          relative to other points, its value can be greater than ‘1.0’.

      -- Method: cdf (x)

          Using a cumulative distribution function (cdf)(11), compute
          the probability that a random variable 'X' will be less than
          or equal to 'x'.  Mathematically, it is written ‘P(X <= x)’.

      -- Method: inv_cdf (p)

          Compute the inverse cumulative distribution function, also
          known as the quantile function(12) or the percent-point(13)
          function.  Mathematically, it is written ‘x : P(X <= x) = p’.

          Finds the value 'x' of the random variable 'X' such that the
          probability of the variable being less than or equal to that
          value equals the given probability 'p'.

      -- Method: overlap (other)

          Measures the agreement between two normal probability
          distributions.  Returns a value between 0.0 and 1.0 giving the
          overlapping area for the two probability density
          functions(14).

      -- Method: quantiles (n=4)

          Divide the normal distribution into 'n' continuous intervals
          with equal probability.  Returns a list of (n - 1) cut points
          separating the intervals.

          Set 'n' to 4 for quartiles (the default).  Set 'n' to 10 for
          deciles.  Set 'n' to 100 for percentiles which gives the 99
          cuts points that separate the normal distribution into 100
          equal sized groups.

      -- Method: zscore (x)

          Compute the Standard Score(15) describing 'x' in terms of the
          number of standard deviations above or below the mean of the
          normal distribution: ‘(x - mean) / stdev’.

          Added in version 3.9.

     Instances of ‘NormalDist’ support addition, subtraction,
     multiplication and division by a constant.  These operations are
     used for translation and scaling.  For example:

          >>> temperature_february = NormalDist(5, 2.5)             # Celsius
          >>> temperature_february * (9/5) + 32                     # Fahrenheit
          NormalDist(mu=41.0, sigma=4.5)

     Dividing a constant by an instance of ‘NormalDist’ is not supported
     because the result wouldn’t be normally distributed.

     Since normal distributions arise from additive effects of
     independent variables, it is possible to add and subtract two
     independent normally distributed random variables(16) represented
     as instances of ‘NormalDist’.  For example:

          >>> birth_weights = NormalDist.from_samples([2.5, 3.1, 2.1, 2.4, 2.7, 3.5])
          >>> drug_effects = NormalDist(0.4, 0.15)
          >>> combined = birth_weights + drug_effects
          >>> round(combined.mean, 1)
          3.1
          >>> round(combined.stdev, 1)
          0.5

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) http://www.stat.yale.edu/Courses/1997-98/101/ranvar.htm

   (2) https://en.wikipedia.org/wiki/Central_limit_theorem

   (3) https://en.wikipedia.org/wiki/Arithmetic_mean

   (4) https://en.wikipedia.org/wiki/Standard_deviation

   (5) https://en.wikipedia.org/wiki/Arithmetic_mean

   (6) https://en.wikipedia.org/wiki/Median

   (7) https://en.wikipedia.org/wiki/Mode_(statistics)

   (8) https://en.wikipedia.org/wiki/Standard_deviation

   (9) https://en.wikipedia.org/wiki/Variance

   (10) https://en.wikipedia.org/wiki/Probability_density_function

   (11) https://en.wikipedia.org/wiki/Cumulative_distribution_function

   (12) https://en.wikipedia.org/wiki/Quantile_function

   (13) 
https://web.archive.org/web/20190203145224/https://www.statisticshowto.datasciencecentral.com/inverse-distribution-function/

   (14) https://www.rasch.org/rmt/rmt101r.htm

   (15) 
https://www.statisticshowto.com/probability-and-statistics/z-score/

   (16) 
https://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables


File: python.info,  Node: Examples and Recipes<2>,  Prev: NormalDist objects,  Up: statistics — Mathematical statistics functions

5.9.7.7 Examples and Recipes
............................

* Menu:

* Classic probability problems::
* Monte Carlo inputs for simulations::
* Approximating binomial distributions::
* Naive bayesian classifier::


File: python.info,  Node: Classic probability problems,  Next: Monte Carlo inputs for simulations,  Up: Examples and Recipes<2>

5.9.7.8 Classic probability problems
....................................

*note NormalDist: a45. readily solves classic probability problems.

For example, given historical data for SAT exams(1) showing that scores
are normally distributed with a mean of 1060 and a standard deviation of
195, determine the percentage of students with test scores between 1100
and 1200, after rounding to the nearest whole number:

     >>> sat = NormalDist(1060, 195)
     >>> fraction = sat.cdf(1200 + 0.5) - sat.cdf(1100 - 0.5)
     >>> round(fraction * 100.0, 1)
     18.4

Find the quartiles(2) and deciles(3) for the SAT scores:

     >>> list(map(round, sat.quantiles()))
     [928, 1060, 1192]
     >>> list(map(round, sat.quantiles(n=10)))
     [810, 896, 958, 1011, 1060, 1109, 1162, 1224, 1310]

   ---------- Footnotes ----------

   (1) https://nces.ed.gov/programs/digest/d17/tables/dt17_226.40.asp

   (2) https://en.wikipedia.org/wiki/Quartile

   (3) https://en.wikipedia.org/wiki/Decile


File: python.info,  Node: Monte Carlo inputs for simulations,  Next: Approximating binomial distributions,  Prev: Classic probability problems,  Up: Examples and Recipes<2>

5.9.7.9 Monte Carlo inputs for simulations
..........................................

To estimate the distribution for a model that isn’t easy to solve
analytically, *note NormalDist: a45. can generate input samples for a
Monte Carlo simulation(1):

     >>> def model(x, y, z):
     ...     return (3*x + 7*x*y - 5*y) / (11 * z)
     ...
     >>> n = 100_000
     >>> X = NormalDist(10, 2.5).samples(n, seed=3652260728)
     >>> Y = NormalDist(15, 1.75).samples(n, seed=4582495471)
     >>> Z = NormalDist(50, 1.25).samples(n, seed=6582483453)
     >>> quantiles(map(model, X, Y, Z))
     [1.4591308524824727, 1.8035946855390597, 2.175091447274739]

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Monte_Carlo_method


File: python.info,  Node: Approximating binomial distributions,  Next: Naive bayesian classifier,  Prev: Monte Carlo inputs for simulations,  Up: Examples and Recipes<2>

5.9.7.10 Approximating binomial distributions
.............................................

Normal distributions can be used to approximate Binomial
distributions(1) when the sample size is large and when the probability
of a successful trial is near 50%.

For example, an open source conference has 750 attendees and two rooms
with a 500 person capacity.  There is a talk about Python and another
about Ruby.  In previous conferences, 65% of the attendees preferred to
listen to Python talks.  Assuming the population preferences haven’t
changed, what is the probability that the Python room will stay within
its capacity limits?

     >>> n = 750             # Sample size
     >>> p = 0.65            # Preference for Python
     >>> q = 1.0 - p         # Preference for Ruby
     >>> k = 500             # Room capacity

     >>> # Approximation using the cumulative normal distribution
     >>> from math import sqrt
     >>> round(NormalDist(mu=n*p, sigma=sqrt(n*p*q)).cdf(k + 0.5), 4)
     0.8402

     >>> # Exact solution using the cumulative binomial distribution
     >>> from math import comb, fsum
     >>> round(fsum(comb(n, r) * p**r * q**(n-r) for r in range(k+1)), 4)
     0.8402

     >>> # Approximation using a simulation
     >>> from random import seed, binomialvariate
     >>> seed(8675309)
     >>> mean(binomialvariate(n, p) <= k for i in range(10_000))
     0.8406

   ---------- Footnotes ----------

   (1) https://mathworld.wolfram.com/BinomialDistribution.html


File: python.info,  Node: Naive bayesian classifier,  Prev: Approximating binomial distributions,  Up: Examples and Recipes<2>

5.9.7.11 Naive bayesian classifier
..................................

Normal distributions commonly arise in machine learning problems.

Wikipedia has a nice example of a Naive Bayesian Classifier(1).  The
challenge is to predict a person’s gender from measurements of normally
distributed features including height, weight, and foot size.

We’re given a training dataset with measurements for eight people.  The
measurements are assumed to be normally distributed, so we summarize the
data with *note NormalDist: a45.:

     >>> height_male = NormalDist.from_samples([6, 5.92, 5.58, 5.92])
     >>> height_female = NormalDist.from_samples([5, 5.5, 5.42, 5.75])
     >>> weight_male = NormalDist.from_samples([180, 190, 170, 165])
     >>> weight_female = NormalDist.from_samples([100, 150, 130, 150])
     >>> foot_size_male = NormalDist.from_samples([12, 11, 12, 10])
     >>> foot_size_female = NormalDist.from_samples([6, 8, 7, 9])

Next, we encounter a new person whose feature measurements are known but
whose gender is unknown:

     >>> ht = 6.0        # height
     >>> wt = 130        # weight
     >>> fs = 8          # foot size

Starting with a 50% prior probability(2) of being male or female, we
compute the posterior as the prior times the product of likelihoods for
the feature measurements given the gender:

     >>> prior_male = 0.5
     >>> prior_female = 0.5
     >>> posterior_male = (prior_male * height_male.pdf(ht) *
     ...                   weight_male.pdf(wt) * foot_size_male.pdf(fs))

     >>> posterior_female = (prior_female * height_female.pdf(ht) *
     ...                     weight_female.pdf(wt) * foot_size_female.pdf(fs))

The final prediction goes to the largest posterior.  This is known as
the maximum a posteriori(3) or MAP:

     >>> 'male' if posterior_male > posterior_female else 'female'
     'female'

   ---------- Footnotes ----------

   (1) 
https://en.wikipedia.org/wiki/Naive_Bayes_classifier#Person_classification

   (2) https://en.wikipedia.org/wiki/Prior_probability

   (3) https://en.wikipedia.org/wiki/Maximum_a_posteriori_estimation


File: python.info,  Node: Functional Programming Modules,  Next: File and Directory Access,  Prev: Numeric and Mathematical Modules,  Up: The Python Standard Library

5.10 Functional Programming Modules
===================================

The modules described in this chapter provide functions and classes that
support a functional programming style, and general operations on
callables.

The following modules are documented in this chapter:

* Menu:

* itertools — Functions creating iterators for efficient looping::
* functools — Higher-order functions and operations on callable objects::
* operator — Standard operators as functions::


File: python.info,  Node: itertools — Functions creating iterators for efficient looping,  Next: functools — Higher-order functions and operations on callable objects,  Up: Functional Programming Modules

5.10.1 ‘itertools’ — Functions creating iterators for efficient looping
-----------------------------------------------------------------------

__________________________________________________________________

This module implements a number of *note iterator: 1ac. building blocks
inspired by constructs from APL, Haskell, and SML. Each has been recast
in a form suitable for Python.

The module standardizes a core set of fast, memory efficient tools that
are useful by themselves or in combination.  Together, they form an
“iterator algebra” making it possible to construct specialized tools
succinctly and efficiently in pure Python.

For instance, SML provides a tabulation tool: ‘tabulate(f)’ which
produces a sequence ‘f(0), f(1), ...’.  The same effect can be achieved
in Python by combining *note map(): 86a. and *note count(): 12ca. to
form ‘map(f, count())’.

'Infinite iterators:'

Iterator               Arguments             Results                                               Example
                                                                                                   
-------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   
*note count(): 12ca.   [start[, step]]       start, start+step, start+2*step, …                    ‘count(10) → 10 11 12 13 14 ...’
                                                                                                   
                                                                                                   
*note cycle(): 28f6.   p                     p0, p1, … plast, p0, p1, …                            ‘cycle('ABCD') → A B C D A B C D ...’
                                                                                                   
                                                                                                   
*note repeat(): 28f7.  elem [,n]             elem, elem, elem, … endlessly or up to n times        ‘repeat(10, 3) → 10 10 10’
                                                                                                   

'Iterators terminating on the shortest input sequence:'

Iterator                         Arguments                        Results                                               Example
                                                                                                                        
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                        
*note accumulate(): a08.         p [,func]                        p0, p0+p1, p0+p1+p2, …                                ‘accumulate([1,2,3,4,5]) → 1 3 6 10 15’
                                                                                                                        
                                                                                                                        
*note batched(): 201.            p, n                             (p0, p1, …, p_n-1), …                                 ‘batched('ABCDEFG', n=3) → ABC DEF G’
                                                                                                                        
                                                                                                                        
*note chain(): 2338.             p, q, …                          p0, p1, … plast, q0, q1, …                            ‘chain('ABC', 'DEF') → A B C D E F’
                                                                                                                        
                                                                                                                        
*note chain.from_iterable(): 28f8.iterable                        p0, p1, … plast, q0, q1, …                            ‘chain.from_iterable(['ABC', 'DEF']) → A B C D E F’
                                                                                                                        
                                                                                                                        
*note compress(): 12c9.          data, selectors                  (d[0] if s[0]), (d[1] if s[1]), …                     ‘compress('ABCDEF', [1,0,1,0,1,1]) → A C E F’
                                                                                                                        
                                                                                                                        
*note dropwhile(): 28f9.         predicate, seq                   seq[n], seq[n+1], starting when predicate fails       ‘dropwhile(lambda x: x<5, [1,4,6,3,8]) → 6 3 8’
                                                                                                                        
                                                                                                                        
*note filterfalse(): 2326.       predicate, seq                   elements of seq where predicate(elem) fails           ‘filterfalse(lambda x: x<5, [1,4,6,3,8]) → 6 8’
                                                                                                                        
                                                                                                                        
*note groupby(): 15aa.           iterable[, key]                  sub-iterators grouped by value of key(v)              ‘groupby(['A','B','DEF'], len) → (1, A B) (3, DEF)’
                                                                                                                        
                                                                                                                        
*note islice(): b67.             seq, [start,] stop [, step]      elements from seq[start:stop:step]                    ‘islice('ABCDEFG', 2, None) → C D E F G’
                                                                                                                        
                                                                                                                        
*note pairwise(): 81b.           iterable                         (p[0], p[1]), (p[1], p[2])                            ‘pairwise('ABCDEFG') → AB BC CD DE EF FG’
                                                                                                                        
                                                                                                                        
*note starmap(): 1128.           func, seq                        func(*seq[0]), func(*seq[1]), …                       ‘starmap(pow, [(2,5), (3,2), (10,3)]) → 32 9 1000’
                                                                                                                        
                                                                                                                        
*note takewhile(): 28fa.         predicate, seq                   seq[0], seq[1], until predicate fails                 ‘takewhile(lambda x: x<5, [1,4,6,3,8]) → 1 4’
                                                                                                                        
                                                                                                                        
*note tee(): 28fb.               it, n                            it1, it2, … itn splits one iterator into n
                                                                  
                                                                                                                        
*note zip_longest(): 12e5.       p, q, …                          (p[0], q[0]), (p[1], q[1]), …                         ‘zip_longest('ABCD', 'xy', fillvalue='-') → Ax By C- D-’
                                                                                                                        

'Combinatoric iterators:'

Iterator                                           Arguments                Results
                                                                            
----------------------------------------------------------------------------------------------------------------------------------------------
                                                                            
*note product(): 135c.                             p, q, … [repeat=1]       cartesian product, equivalent to a nested for-loop
                                                                            
                                                                            
*note permutations(): 1a84.                        p[, r]                   r-length tuples, all possible orderings, no repeated elements
                                                                            
                                                                            
*note combinations(): 135b.                        p, r                     r-length tuples, in sorted order, no repeated elements
                                                                            
                                                                            
*note combinations_with_replacement(): 12c8.       p, r                     r-length tuples, in sorted order, with repeated elements
                                                                            

Examples                                           Results
                                                   
---------------------------------------------------------------------------------------------------------------------
                                                   
‘product('ABCD', repeat=2)’                        ‘AA AB AC AD BA BB BC BD CA CB CC CD DA DB DC DD’
                                                   
                                                   
‘permutations('ABCD', 2)’                          ‘AB AC AD BA BC BD CA CB CD DA DB DC’
                                                   
                                                   
‘combinations('ABCD', 2)’                          ‘AB AC AD BC BD CD’
                                                   
                                                   
‘combinations_with_replacement('ABCD', 2)’         ‘AA AB AC AD BB BC BD CC CD DD’
                                                   

* Menu:

* Itertool Functions::
* Itertools Recipes::


File: python.info,  Node: Itertool Functions,  Next: Itertools Recipes,  Up: itertools — Functions creating iterators for efficient looping

5.10.1.1 Itertool Functions
...........................

The following functions all construct and return iterators.  Some
provide streams of infinite length, so they should only be accessed by
functions or loops that truncate the stream.

 -- Function: itertools.accumulate (iterable[, function, *,
          initial=None])

     Make an iterator that returns accumulated sums or accumulated
     results from other binary functions.

     The 'function' defaults to addition.  The 'function' should accept
     two arguments, an accumulated total and a value from the
     'iterable'.

     If an 'initial' value is provided, the accumulation will start with
     that value and the output will have one more element than the input
     iterable.

     Roughly equivalent to:

          def accumulate(iterable, function=operator.add, *, initial=None):
              'Return running totals'
              # accumulate([1,2,3,4,5]) → 1 3 6 10 15
              # accumulate([1,2,3,4,5], initial=100) → 100 101 103 106 110 115
              # accumulate([1,2,3,4,5], operator.mul) → 1 2 6 24 120

              iterator = iter(iterable)
              total = initial
              if initial is None:
                  try:
                      total = next(iterator)
                  except StopIteration:
                      return

              yield total
              for element in iterator:
                  total = function(total, element)
                  yield total

     To compute a running minimum, set 'function' to *note min(): f3f.
     For a running maximum, set 'function' to *note max(): f40.  Or for
     a running product, set 'function' to *note operator.mul(): 28fe.
     To build an amortization table(1), accumulate the interest and
     apply payments:

          >>> data = [3, 4, 6, 2, 1, 9, 0, 7, 5, 8]
          >>> list(accumulate(data, max))              # running maximum
          [3, 4, 6, 6, 6, 9, 9, 9, 9, 9]
          >>> list(accumulate(data, operator.mul))     # running product
          [3, 12, 72, 144, 144, 1296, 0, 0, 0, 0]

          # Amortize a 5% loan of 1000 with 10 annual payments of 90
          >>> update = lambda balance, payment: round(balance * 1.05) - payment
          >>> list(accumulate(repeat(90, 10), update, initial=1_000))
          [1000, 960, 918, 874, 828, 779, 728, 674, 618, 559, 497]

     See *note functools.reduce(): 1324. for a similar function that
     returns only the final accumulated value.

     Added in version 3.2.

     Changed in version 3.3: Added the optional 'function' parameter.

     Changed in version 3.8: Added the optional 'initial' parameter.

 -- Function: itertools.batched (iterable, n, *, strict=False)

     Batch data from the 'iterable' into tuples of length 'n'.  The last
     batch may be shorter than 'n'.

     If 'strict' is true, will raise a *note ValueError: 202. if the
     final batch is shorter than 'n'.

     Loops over the input iterable and accumulates data into tuples up
     to size 'n'.  The input is consumed lazily, just enough to fill a
     batch.  The result is yielded as soon as the batch is full or when
     the input iterable is exhausted:

          >>> flattened_data = ['roses', 'red', 'violets', 'blue', 'sugar', 'sweet']
          >>> unflattened = list(batched(flattened_data, 2))
          >>> unflattened
          [('roses', 'red'), ('violets', 'blue'), ('sugar', 'sweet')]

     Roughly equivalent to:

          def batched(iterable, n, *, strict=False):
              # batched('ABCDEFG', 3) → ABC DEF G
              if n < 1:
                  raise ValueError('n must be at least one')
              iterator = iter(iterable)
              while batch := tuple(islice(iterator, n)):
                  if strict and len(batch) != n:
                      raise ValueError('batched(): incomplete batch')
                  yield batch

     Added in version 3.12.

     Changed in version 3.13: Added the 'strict' option.

 -- Function: itertools.chain (*iterables)

     Make an iterator that returns elements from the first iterable
     until it is exhausted, then proceeds to the next iterable, until
     all of the iterables are exhausted.  This combines multiple data
     sources into a single iterator.  Roughly equivalent to:

          def chain(*iterables):
              # chain('ABC', 'DEF') → A B C D E F
              for iterable in iterables:
                  yield from iterable

 -- Method: classmethod chain.from_iterable (iterable)

     Alternate constructor for *note chain(): 2338.  Gets chained inputs
     from a single iterable argument that is evaluated lazily.  Roughly
     equivalent to:

          def from_iterable(iterables):
              # chain.from_iterable(['ABC', 'DEF']) → A B C D E F
              for iterable in iterables:
                  yield from iterable

 -- Function: itertools.combinations (iterable, r)

     Return 'r' length subsequences of elements from the input
     'iterable'.

     The output is a subsequence of *note product(): 135c. keeping only
     entries that are subsequences of the 'iterable'.  The length of the
     output is given by *note math.comb(): 6d3. which computes ‘n! / r!
     / (n - r)!’ when ‘0 ≤ r ≤ n’ or zero when ‘r > n’.

     The combination tuples are emitted in lexicographic order according
     to the order of the input 'iterable'.  If the input 'iterable' is
     sorted, the output tuples will be produced in sorted order.

     Elements are treated as unique based on their position, not on
     their value.  If the input elements are unique, there will be no
     repeated values within each combination.

     Roughly equivalent to:

          def combinations(iterable, r):
              # combinations('ABCD', 2) → AB AC AD BC BD CD
              # combinations(range(4), 3) → 012 013 023 123

              pool = tuple(iterable)
              n = len(pool)
              if r > n:
                  return
              indices = list(range(r))

              yield tuple(pool[i] for i in indices)
              while True:
                  for i in reversed(range(r)):
                      if indices[i] != i + n - r:
                          break
                  else:
                      return
                  indices[i] += 1
                  for j in range(i+1, r):
                      indices[j] = indices[j-1] + 1
                  yield tuple(pool[i] for i in indices)

 -- Function: itertools.combinations_with_replacement (iterable, r)

     Return 'r' length subsequences of elements from the input
     'iterable' allowing individual elements to be repeated more than
     once.

     The output is a subsequence of *note product(): 135c. that keeps
     only entries that are subsequences (with possible repeated
     elements) of the 'iterable'.  The number of subsequence returned is
     ‘(n + r - 1)! / r! / (n - 1)!’ when ‘n > 0’.

     The combination tuples are emitted in lexicographic order according
     to the order of the input 'iterable'.  if the input 'iterable' is
     sorted, the output tuples will be produced in sorted order.

     Elements are treated as unique based on their position, not on
     their value.  If the input elements are unique, the generated
     combinations will also be unique.

     Roughly equivalent to:

          def combinations_with_replacement(iterable, r):
              # combinations_with_replacement('ABC', 2) → AA AB AC BB BC CC

              pool = tuple(iterable)
              n = len(pool)
              if not n and r:
                  return
              indices = [0] * r

              yield tuple(pool[i] for i in indices)
              while True:
                  for i in reversed(range(r)):
                      if indices[i] != n - 1:
                          break
                  else:
                      return
                  indices[i:] = [indices[i] + 1] * (r - i)
                  yield tuple(pool[i] for i in indices)

     Added in version 3.1.

 -- Function: itertools.compress (data, selectors)

     Make an iterator that returns elements from 'data' where the
     corresponding element in 'selectors' is true.  Stops when either
     the 'data' or 'selectors' iterables have been exhausted.  Roughly
     equivalent to:

          def compress(data, selectors):
              # compress('ABCDEF', [1,0,1,0,1,1]) → A C E F
              return (datum for datum, selector in zip(data, selectors) if selector)

     Added in version 3.1.

 -- Function: itertools.count (start=0, step=1)

     Make an iterator that returns evenly spaced values beginning with
     'start'.  Can be used with *note map(): 86a. to generate
     consecutive data points or with *note zip(): 7d4. to add sequence
     numbers.  Roughly equivalent to:

          def count(start=0, step=1):
              # count(10) → 10 11 12 13 14 ...
              # count(2.5, 0.5) → 2.5 3.0 3.5 ...
              n = start
              while True:
                  yield n
                  n += step

     When counting with floating-point numbers, better accuracy can
     sometimes be achieved by substituting multiplicative code such as:
     ‘(start + step * i for i in count())’.

     Changed in version 3.1: Added 'step' argument and allowed
     non-integer arguments.

 -- Function: itertools.cycle (iterable)

     Make an iterator returning elements from the 'iterable' and saving
     a copy of each.  When the iterable is exhausted, return elements
     from the saved copy.  Repeats indefinitely.  Roughly equivalent to:

          def cycle(iterable):
              # cycle('ABCD') → A B C D A B C D A B C D ...

              saved = []
              for element in iterable:
                  yield element
                  saved.append(element)

              while saved:
                  for element in saved:
                      yield element

     This itertool may require significant auxiliary storage (depending
     on the length of the iterable).

 -- Function: itertools.dropwhile (predicate, iterable)

     Make an iterator that drops elements from the 'iterable' while the
     'predicate' is true and afterwards returns every element.  Roughly
     equivalent to:

          def dropwhile(predicate, iterable):
              # dropwhile(lambda x: x<5, [1,4,6,3,8]) → 6 3 8

              iterator = iter(iterable)
              for x in iterator:
                  if not predicate(x):
                      yield x
                      break

              for x in iterator:
                  yield x

     Note this does not produce 'any' output until the predicate first
     becomes false, so this itertool may have a lengthy start-up time.

 -- Function: itertools.filterfalse (predicate, iterable)

     Make an iterator that filters elements from the 'iterable'
     returning only those for which the 'predicate' returns a false
     value.  If 'predicate' is ‘None’, returns the items that are false.
     Roughly equivalent to:

          def filterfalse(predicate, iterable):
              # filterfalse(lambda x: x<5, [1,4,6,3,8]) → 6 8

              if predicate is None:
                  predicate = bool

              for x in iterable:
                  if not predicate(x):
                      yield x

 -- Function: itertools.groupby (iterable, key=None)

     Make an iterator that returns consecutive keys and groups from the
     'iterable'.  The 'key' is a function computing a key value for each
     element.  If not specified or is ‘None’, 'key' defaults to an
     identity function and returns the element unchanged.  Generally,
     the iterable needs to already be sorted on the same key function.

     The operation of ‘groupby()’ is similar to the ‘uniq’ filter in
     Unix.  It generates a break or new group every time the value of
     the key function changes (which is why it is usually necessary to
     have sorted the data using the same key function).  That behavior
     differs from SQL’s GROUP BY which aggregates common elements
     regardless of their input order.

     The returned group is itself an iterator that shares the underlying
     iterable with ‘groupby()’.  Because the source is shared, when the
     ‘groupby()’ object is advanced, the previous group is no longer
     visible.  So, if that data is needed later, it should be stored as
     a list:

          groups = []
          uniquekeys = []
          data = sorted(data, key=keyfunc)
          for k, g in groupby(data, keyfunc):
              groups.append(list(g))      # Store group iterator as a list
              uniquekeys.append(k)

     ‘groupby()’ is roughly equivalent to:

          def groupby(iterable, key=None):
              # [k for k, g in groupby('AAAABBBCCDAABBB')] → A B C D A B
              # [list(g) for k, g in groupby('AAAABBBCCD')] → AAAA BBB CC D

              keyfunc = (lambda x: x) if key is None else key
              iterator = iter(iterable)
              exhausted = False

              def _grouper(target_key):
                  nonlocal curr_value, curr_key, exhausted
                  yield curr_value
                  for curr_value in iterator:
                      curr_key = keyfunc(curr_value)
                      if curr_key != target_key:
                          return
                      yield curr_value
                  exhausted = True

              try:
                  curr_value = next(iterator)
              except StopIteration:
                  return
              curr_key = keyfunc(curr_value)

              while not exhausted:
                  target_key = curr_key
                  curr_group = _grouper(target_key)
                  yield curr_key, curr_group
                  if curr_key == target_key:
                      for _ in curr_group:
                          pass

 -- Function: itertools.islice (iterable, stop)

 -- Function: itertools.islice (iterable, start, stop[, step])

     Make an iterator that returns selected elements from the iterable.
     Works like sequence slicing but does not support negative values
     for 'start', 'stop', or 'step'.

     If 'start' is zero or ‘None’, iteration starts at zero.  Otherwise,
     elements from the iterable are skipped until 'start' is reached.

     If 'stop' is ‘None’, iteration continues until the input is
     exhausted, if at all.  Otherwise, it stops at the specified
     position.

     If 'step' is ‘None’, the step defaults to one.  Elements are
     returned consecutively unless 'step' is set higher than one which
     results in items being skipped.

     Roughly equivalent to:

          def islice(iterable, *args):
              # islice('ABCDEFG', 2) → A B
              # islice('ABCDEFG', 2, 4) → C D
              # islice('ABCDEFG', 2, None) → C D E F G
              # islice('ABCDEFG', 0, None, 2) → A C E G

              s = slice(*args)
              start = 0 if s.start is None else s.start
              stop = s.stop
              step = 1 if s.step is None else s.step
              if start < 0 or (stop is not None and stop < 0) or step <= 0:
                  raise ValueError

              indices = count() if stop is None else range(max(start, stop))
              next_i = start
              for i, element in zip(indices, iterable):
                  if i == next_i:
                      yield element
                      next_i += step

     If the input is an iterator, then fully consuming the 'islice'
     advances the input iterator by ‘max(start, stop)’ steps regardless
     of the 'step' value.

 -- Function: itertools.pairwise (iterable)

     Return successive overlapping pairs taken from the input
     'iterable'.

     The number of 2-tuples in the output iterator will be one fewer
     than the number of inputs.  It will be empty if the input iterable
     has fewer than two values.

     Roughly equivalent to:

          def pairwise(iterable):
              # pairwise('ABCDEFG') → AB BC CD DE EF FG

              iterator = iter(iterable)
              a = next(iterator, None)

              for b in iterator:
                  yield a, b
                  a = b

     Added in version 3.10.

 -- Function: itertools.permutations (iterable, r=None)

     Return successive 'r' length permutations of elements(2) from the
     'iterable'.

     If 'r' is not specified or is ‘None’, then 'r' defaults to the
     length of the 'iterable' and all possible full-length permutations
     are generated.

     The output is a subsequence of *note product(): 135c. where entries
     with repeated elements have been filtered out.  The length of the
     output is given by *note math.perm(): 6d4. which computes ‘n! / (n
     - r)!’ when ‘0 ≤ r ≤ n’ or zero when ‘r > n’.

     The permutation tuples are emitted in lexicographic order according
     to the order of the input 'iterable'.  If the input 'iterable' is
     sorted, the output tuples will be produced in sorted order.

     Elements are treated as unique based on their position, not on
     their value.  If the input elements are unique, there will be no
     repeated values within a permutation.

     Roughly equivalent to:

          def permutations(iterable, r=None):
              # permutations('ABCD', 2) → AB AC AD BA BC BD CA CB CD DA DB DC
              # permutations(range(3)) → 012 021 102 120 201 210

              pool = tuple(iterable)
              n = len(pool)
              r = n if r is None else r
              if r > n:
                  return

              indices = list(range(n))
              cycles = list(range(n, n-r, -1))
              yield tuple(pool[i] for i in indices[:r])

              while n:
                  for i in reversed(range(r)):
                      cycles[i] -= 1
                      if cycles[i] == 0:
                          indices[i:] = indices[i+1:] + indices[i:i+1]
                          cycles[i] = n - i
                      else:
                          j = cycles[i]
                          indices[i], indices[-j] = indices[-j], indices[i]
                          yield tuple(pool[i] for i in indices[:r])
                          break
                  else:
                      return

 -- Function: itertools.product (*iterables, repeat=1)

     Cartesian product(3) of the input iterables.

     Roughly equivalent to nested for-loops in a generator expression.
     For example, ‘product(A, B)’ returns the same as ‘((x,y) for x in A
     for y in B)’.

     The nested loops cycle like an odometer with the rightmost element
     advancing on every iteration.  This pattern creates a lexicographic
     ordering so that if the input’s iterables are sorted, the product
     tuples are emitted in sorted order.

     To compute the product of an iterable with itself, specify the
     number of repetitions with the optional 'repeat' keyword argument.
     For example, ‘product(A, repeat=4)’ means the same as ‘product(A,
     A, A, A)’.

     This function is roughly equivalent to the following code, except
     that the actual implementation does not build up intermediate
     results in memory:

          def product(*iterables, repeat=1):
              # product('ABCD', 'xy') → Ax Ay Bx By Cx Cy Dx Dy
              # product(range(2), repeat=3) → 000 001 010 011 100 101 110 111

              if repeat < 0:
                  raise ValueError('repeat argument cannot be negative')
              pools = [tuple(pool) for pool in iterables] * repeat

              result = [[]]
              for pool in pools:
                  result = [x+[y] for x in result for y in pool]

              for prod in result:
                  yield tuple(prod)

     Before ‘product()’ runs, it completely consumes the input
     iterables, keeping pools of values in memory to generate the
     products.  Accordingly, it is only useful with finite inputs.

 -- Function: itertools.repeat (object[, times])

     Make an iterator that returns 'object' over and over again.  Runs
     indefinitely unless the 'times' argument is specified.

     Roughly equivalent to:

          def repeat(object, times=None):
              # repeat(10, 3) → 10 10 10
              if times is None:
                  while True:
                      yield object
              else:
                  for i in range(times):
                      yield object

     A common use for 'repeat' is to supply a stream of constant values
     to 'map' or 'zip':

          >>> list(map(pow, range(10), repeat(2)))
          [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

 -- Function: itertools.starmap (function, iterable)

     Make an iterator that computes the 'function' using arguments
     obtained from the 'iterable'.  Used instead of *note map(): 86a.
     when argument parameters have already been “pre-zipped” into
     tuples.

     The difference between *note map(): 86a. and ‘starmap()’ parallels
     the distinction between ‘function(a,b)’ and ‘function(*c)’.
     Roughly equivalent to:

          def starmap(function, iterable):
              # starmap(pow, [(2,5), (3,2), (10,3)]) → 32 9 1000
              for args in iterable:
                  yield function(*args)

 -- Function: itertools.takewhile (predicate, iterable)

     Make an iterator that returns elements from the 'iterable' as long
     as the 'predicate' is true.  Roughly equivalent to:

          def takewhile(predicate, iterable):
              # takewhile(lambda x: x<5, [1,4,6,3,8]) → 1 4
              for x in iterable:
                  if not predicate(x):
                      break
                  yield x

     Note, the element that first fails the predicate condition is
     consumed from the input iterator and there is no way to access it.
     This could be an issue if an application wants to further consume
     the input iterator after 'takewhile' has been run to exhaustion.
     To work around this problem, consider using more-itertools
     before_and_after()(4) instead.

 -- Function: itertools.tee (iterable, n=2)

     Return 'n' independent iterators from a single iterable.

     Roughly equivalent to:

          def tee(iterable, n=2):
              if n < 0:
                  raise ValueError
              if n == 0:
                  return ()
              iterator = _tee(iterable)
              result = [iterator]
              for _ in range(n - 1):
                  result.append(_tee(iterator))
              return tuple(result)

          class _tee:

              def __init__(self, iterable):
                  it = iter(iterable)
                  if isinstance(it, _tee):
                      self.iterator = it.iterator
                      self.link = it.link
                  else:
                      self.iterator = it
                      self.link = [None, None]

              def __iter__(self):
                  return self

              def __next__(self):
                  link = self.link
                  if link[1] is None:
                      link[0] = next(self.iterator)
                      link[1] = [None, None]
                  value, self.link = link
                  return value

     When the input 'iterable' is already a tee iterator object, all
     members of the return tuple are constructed as if they had been
     produced by the upstream ‘tee()’ call.  This “flattening step”
     allows nested ‘tee()’ calls to share the same underlying data chain
     and to have a single update step rather than a chain of calls.

     The flattening property makes tee iterators efficiently peekable:

          def lookahead(tee_iterator):
               "Return the next value without moving the input forward"
               [forked_iterator] = tee(tee_iterator, 1)
               return next(forked_iterator)

          >>> iterator = iter('abcdef')
          >>> [iterator] = tee(iterator, 1)   # Make the input peekable
          >>> next(iterator)                  # Move the iterator forward
          'a'
          >>> lookahead(iterator)             # Check next value
          'b'
          >>> next(iterator)                  # Continue moving forward
          'b'

     ‘tee’ iterators are not threadsafe.  A *note RuntimeError: 195. may
     be raised when simultaneously using iterators returned by the same
     ‘tee()’ call, even if the original 'iterable' is threadsafe.

     This itertool may require significant auxiliary storage (depending
     on how much temporary data needs to be stored).  In general, if one
     iterator uses most or all of the data before another iterator
     starts, it is faster to use *note list(): 614. instead of ‘tee()’.

 -- Function: itertools.zip_longest (*iterables, fillvalue=None)

     Make an iterator that aggregates elements from each of the
     'iterables'.

     If the iterables are of uneven length, missing values are filled-in
     with 'fillvalue'.  If not specified, 'fillvalue' defaults to
     ‘None’.

     Iteration continues until the longest iterable is exhausted.

     Roughly equivalent to:

          def zip_longest(*iterables, fillvalue=None):
              # zip_longest('ABCD', 'xy', fillvalue='-') → Ax By C- D-

              iterators = list(map(iter, iterables))
              num_active = len(iterators)
              if not num_active:
                  return

              while True:
                  values = []
                  for i, iterator in enumerate(iterators):
                      try:
                          value = next(iterator)
                      except StopIteration:
                          num_active -= 1
                          if not num_active:
                              return
                          iterators[i] = repeat(fillvalue)
                          value = fillvalue
                      values.append(value)
                  yield tuple(values)

     If one of the iterables is potentially infinite, then the
     ‘zip_longest()’ function should be wrapped with something that
     limits the number of calls (for example *note islice(): b67. or
     *note takewhile(): 28fa.).

   ---------- Footnotes ----------

   (1) https://www.ramseysolutions.com/real-estate/amortization-schedule

   (2) https://www.britannica.com/science/permutation

   (3) https://en.wikipedia.org/wiki/Cartesian_product

   (4) 
https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.before_and_after


File: python.info,  Node: Itertools Recipes,  Prev: Itertool Functions,  Up: itertools — Functions creating iterators for efficient looping

5.10.1.2 Itertools Recipes
..........................

This section shows recipes for creating an extended toolset using the
existing itertools as building blocks.

The primary purpose of the itertools recipes is educational.  The
recipes show various ways of thinking about individual tools — for
example, that ‘chain.from_iterable’ is related to the concept of
flattening.  The recipes also give ideas about ways that the tools can
be combined — for example, how ‘starmap()’ and ‘repeat()’ can work
together.  The recipes also show patterns for using itertools with the
*note operator: 9f. and *note collections: 1d. modules as well as with
the built-in itertools such as ‘map()’, ‘filter()’, ‘reversed()’, and
‘enumerate()’.

A secondary purpose of the recipes is to serve as an incubator.  The
‘accumulate()’, ‘compress()’, and ‘pairwise()’ itertools started out as
recipes.  Currently, the ‘sliding_window()’, ‘iter_index()’, and
‘sieve()’ recipes are being tested to see whether they prove their
worth.

Substantially all of these recipes and many, many others can be
installed from the more-itertools(1) project found on the Python Package
Index:

     python -m pip install more-itertools

Many of the recipes offer the same high performance as the underlying
toolset.  Superior memory performance is kept by processing elements one
at a time rather than bringing the whole iterable into memory all at
once.  Code volume is kept small by linking the tools together in a
functional style(2).  High speed is retained by preferring “vectorized”
building blocks over the use of for-loops and *note generators: 109f.
which incur interpreter overhead.

     from collections import Counter, deque
     from contextlib import suppress
     from functools import reduce
     from math import comb, prod, sumprod, isqrt
     from operator import itemgetter, getitem, mul, neg, truediv

     def take(n, iterable):
         "Return first n items of the iterable as a list."
         return list(islice(iterable, n))

     def prepend(value, iterable):
         "Prepend a single value in front of an iterable."
         # prepend(1, [2, 3, 4]) → 1 2 3 4
         return chain([value], iterable)

     def running_mean(iterable):
         "Yield the average of all values seen so far."
         # running_mean([8.5, 9.5, 7.5, 6.5]) -> 8.5 9.0 8.5 8.0
         return map(truediv, accumulate(iterable), count(1))

     def repeatfunc(function, times=None, *args):
         "Repeat calls to a function with specified arguments."
         if times is None:
             return starmap(function, repeat(args))
         return starmap(function, repeat(args, times))

     def flatten(list_of_lists):
         "Flatten one level of nesting."
         return chain.from_iterable(list_of_lists)

     def ncycles(iterable, n):
         "Returns the sequence elements n times."
         return chain.from_iterable(repeat(tuple(iterable), n))

     def loops(n):
         "Loop n times. Like range(n) but without creating integers."
         # for _ in loops(100): ...
         return repeat(None, n)

     def tail(n, iterable):
         "Return an iterator over the last n items."
         # tail(3, 'ABCDEFG') → E F G
         return iter(deque(iterable, maxlen=n))

     def consume(iterator, n=None):
         "Advance the iterator n-steps ahead. If n is None, consume entirely."
         # Use functions that consume iterators at C speed.
         if n is None:
             deque(iterator, maxlen=0)
         else:
             next(islice(iterator, n, n), None)

     def nth(iterable, n, default=None):
         "Returns the nth item or a default value."
         return next(islice(iterable, n, None), default)

     def quantify(iterable, predicate=bool):
         "Given a predicate that returns True or False, count the True results."
         return sum(map(predicate, iterable))

     def first_true(iterable, default=False, predicate=None):
         "Returns the first true value or the *default* if there is no true value."
         # first_true([a,b,c], x) → a or b or c or x
         # first_true([a,b], x, f) → a if f(a) else b if f(b) else x
         return next(filter(predicate, iterable), default)

     def all_equal(iterable, key=None):
         "Returns True if all the elements are equal to each other."
         # all_equal('4٤௪౪໔', key=int) → True
         return len(take(2, groupby(iterable, key))) <= 1

     def unique_justseen(iterable, key=None):
         "Yield unique elements, preserving order. Remember only the element just seen."
         # unique_justseen('AAAABBBCCDAABBB') → A B C D A B
         # unique_justseen('ABBcCAD', str.casefold) → A B c A D
         if key is None:
             return map(itemgetter(0), groupby(iterable))
         return map(next, map(itemgetter(1), groupby(iterable, key)))

     def unique_everseen(iterable, key=None):
         "Yield unique elements, preserving order. Remember all elements ever seen."
         # unique_everseen('AAAABBBCCDAABBB') → A B C D
         # unique_everseen('ABBcCAD', str.casefold) → A B c D
         seen = set()
         if key is None:
             for element in filterfalse(seen.__contains__, iterable):
                 seen.add(element)
                 yield element
         else:
             for element in iterable:
                 k = key(element)
                 if k not in seen:
                     seen.add(k)
                     yield element

     def unique(iterable, key=None, reverse=False):
        "Yield unique elements in sorted order. Supports unhashable inputs."
        # unique([[1, 2], [3, 4], [1, 2]]) → [1, 2] [3, 4]
        sequenced = sorted(iterable, key=key, reverse=reverse)
        return unique_justseen(sequenced, key=key)

     def sliding_window(iterable, n):
         "Collect data into overlapping fixed-length chunks or blocks."
         # sliding_window('ABCDEFG', 4) → ABCD BCDE CDEF DEFG
         iterator = iter(iterable)
         window = deque(islice(iterator, n - 1), maxlen=n)
         for x in iterator:
             window.append(x)
             yield tuple(window)

     def grouper(iterable, n, *, incomplete='fill', fillvalue=None):
         "Collect data into non-overlapping fixed-length chunks or blocks."
         # grouper('ABCDEFG', 3, fillvalue='x') → ABC DEF Gxx
         # grouper('ABCDEFG', 3, incomplete='strict') → ABC DEF ValueError
         # grouper('ABCDEFG', 3, incomplete='ignore') → ABC DEF
         iterators = [iter(iterable)] * n
         match incomplete:
             case 'fill':
                 return zip_longest(*iterators, fillvalue=fillvalue)
             case 'strict':
                 return zip(*iterators, strict=True)
             case 'ignore':
                 return zip(*iterators)
             case _:
                 raise ValueError('Expected fill, strict, or ignore')

     def roundrobin(*iterables):
         "Visit input iterables in a cycle until each is exhausted."
         # roundrobin('ABC', 'D', 'EF') → A D E B F C
         # Algorithm credited to George Sakkis
         iterators = map(iter, iterables)
         for num_active in range(len(iterables), 0, -1):
             iterators = cycle(islice(iterators, num_active))
             yield from map(next, iterators)

     def subslices(seq):
         "Return all contiguous non-empty subslices of a sequence."
         # subslices('ABCD') → A AB ABC ABCD B BC BCD C CD D
         slices = starmap(slice, combinations(range(len(seq) + 1), 2))
         return map(getitem, repeat(seq), slices)

     def iter_index(iterable, value, start=0, stop=None):
         "Return indices where a value occurs in a sequence or iterable."
         # iter_index('AABCADEAF', 'A') → 0 1 4 7
         seq_index = getattr(iterable, 'index', None)
         if seq_index is None:
             iterator = islice(iterable, start, stop)
             for i, element in enumerate(iterator, start):
                 if element is value or element == value:
                     yield i
         else:
             stop = len(iterable) if stop is None else stop
             i = start
             with suppress(ValueError):
                 while True:
                     yield (i := seq_index(value, i, stop))
                     i += 1

     def iter_except(function, exception, first=None):
         "Convert a call-until-exception interface to an iterator interface."
         # iter_except(d.popitem, KeyError) → non-blocking dictionary iterator
         with suppress(exception):
             if first is not None:
                 yield first()
             while True:
                 yield function()

The following recipes have a more mathematical flavor:

     def multinomial(*counts):
         "Number of distinct arrangements of a multiset."
         # Counter('abracadabra').values() → 5 2 2 1 1
         # multinomial(5, 2, 2, 1, 1) → 83160
         return prod(map(comb, accumulate(counts), counts))

     def powerset(iterable):
         "Subsequences of the iterable from shortest to longest."
         # powerset([1,2,3]) → () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)
         s = list(iterable)
         return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))

     def sum_of_squares(iterable):
         "Add up the squares of the input values."
         # sum_of_squares([10, 20, 30]) → 1400
         return sumprod(*tee(iterable))

     def reshape(matrix, columns):
         "Reshape a 2-D matrix to have a given number of columns."
         # reshape([(0, 1), (2, 3), (4, 5)], 3) →  (0, 1, 2), (3, 4, 5)
         return batched(chain.from_iterable(matrix), columns, strict=True)

     def transpose(matrix):
         "Swap the rows and columns of a 2-D matrix."
         # transpose([(1, 2, 3), (11, 22, 33)]) → (1, 11) (2, 22) (3, 33)
         return zip(*matrix, strict=True)

     def matmul(m1, m2):
         "Multiply two matrices."
         # matmul([(7, 5), (3, 5)], [(2, 5), (7, 9)]) → (49, 80), (41, 60)
         n = len(m2[0])
         return batched(starmap(sumprod, product(m1, transpose(m2))), n)

     def convolve(signal, kernel):
         """Discrete linear convolution of two iterables.
         Equivalent to polynomial multiplication.

         Convolutions are mathematically commutative; however, the inputs are
         evaluated differently.  The signal is consumed lazily and can be
         infinite. The kernel is fully consumed before the calculations begin.

         Article:  https://betterexplained.com/articles/intuitive-convolution/
         Video:    https://www.youtube.com/watch?v=KuXjwB4LzSA
         """
         # convolve([1, -1, -20], [1, -3]) → 1 -4 -17 60
         # convolve(data, [0.25, 0.25, 0.25, 0.25]) → Moving average (blur)
         # convolve(data, [1/2, 0, -1/2]) → 1st derivative estimate
         # convolve(data, [1, -2, 1]) → 2nd derivative estimate
         kernel = tuple(kernel)[::-1]
         n = len(kernel)
         padded_signal = chain(repeat(0, n-1), signal, repeat(0, n-1))
         windowed_signal = sliding_window(padded_signal, n)
         return map(sumprod, repeat(kernel), windowed_signal)

     def polynomial_from_roots(roots):
         """Compute a polynomial's coefficients from its roots.

            (x - 5) (x + 4) (x - 3)  expands to:   x³ -4x² -17x + 60
         """
         # polynomial_from_roots([5, -4, 3]) → [1, -4, -17, 60]
         factors = zip(repeat(1), map(neg, roots))
         return list(reduce(convolve, factors, [1]))

     def polynomial_eval(coefficients, x):
         """Evaluate a polynomial at a specific value.

         Computes with better numeric stability than Horner's method.
         """
         # Evaluate x³ -4x² -17x + 60 at x = 5
         # polynomial_eval([1, -4, -17, 60], x=5) → 0
         n = len(coefficients)
         if not n:
             return type(x)(0)
         powers = map(pow, repeat(x), reversed(range(n)))
         return sumprod(coefficients, powers)

     def polynomial_derivative(coefficients):
         """Compute the first derivative of a polynomial.

            f(x)  =  x³ -4x² -17x + 60
            f'(x) = 3x² -8x  -17
         """
         # polynomial_derivative([1, -4, -17, 60]) → [3, -8, -17]
         n = len(coefficients)
         powers = reversed(range(1, n))
         return list(map(mul, coefficients, powers))

     def sieve(n):
         "Primes less than n."
         # sieve(30) → 2 3 5 7 11 13 17 19 23 29
         if n > 2:
             yield 2
         data = bytearray((0, 1)) * (n // 2)
         for p in iter_index(data, 1, start=3, stop=isqrt(n) + 1):
             data[p*p : n : p+p] = bytes(len(range(p*p, n, p+p)))
         yield from iter_index(data, 1, start=3)

     def factor(n):
         "Prime factors of n."
         # factor(99) → 3 3 11
         # factor(1_000_000_000_000_007) → 47 59 360620266859
         # factor(1_000_000_000_000_403) → 1000000000000403
         for prime in sieve(isqrt(n) + 1):
             while not n % prime:
                 yield prime
                 n //= prime
                 if n == 1:
                     return
         if n > 1:
             yield n

     def is_prime(n):
         "Return True if n is prime."
         # is_prime(1_000_000_000_000_403) → True
         return n > 1 and next(factor(n)) == n

     def totient(n):
         "Count of natural numbers up to n that are coprime to n."
         # https://mathworld.wolfram.com/TotientFunction.html
         # totient(12) → 4 because len([1, 5, 7, 11]) == 4
         for prime in set(factor(n)):
             n -= n // prime
         return n

   ---------- Footnotes ----------

   (1) https://pypi.org/project/more-itertools/

   (2) https://www.cs.kent.ac.uk/people/staff/dat/miranda/whyfp90.pdf


File: python.info,  Node: functools — Higher-order functions and operations on callable objects,  Next: operator — Standard operators as functions,  Prev: itertools — Functions creating iterators for efficient looping,  Up: Functional Programming Modules

5.10.2 ‘functools’ — Higher-order functions and operations on callable objects
------------------------------------------------------------------------------

'Source code:' Lib/functools.py(1)

__________________________________________________________________

The ‘functools’ module is for higher-order functions: functions that act
on or return other functions.  In general, any callable object can be
treated as a function for the purposes of this module.

The ‘functools’ module defines the following functions:

 -- Function: @functools.cache (user_function)

     Simple lightweight unbounded function cache.  Sometimes called
     "memoize"(2).

     Returns the same as ‘lru_cache(maxsize=None)’, creating a thin
     wrapper around a dictionary lookup for the function arguments.
     Because it never needs to evict old values, this is smaller and
     faster than *note lru_cache(): 9fa. with a size limit.

     For example:

          @cache
          def factorial(n):
              return n * factorial(n-1) if n else 1

          >>> factorial(10)   # no previously cached result, makes 11 recursive calls
          3628800
          >>> factorial(5)    # no new calls, just returns the cached result
          120
          >>> factorial(12)   # two new recursive calls, factorial(10) is cached
          479001600

     The cache is threadsafe so that the wrapped function can be used in
     multiple threads.  This means that the underlying data structure
     will remain coherent during concurrent updates.

     It is possible for the wrapped function to be called more than once
     if another thread makes an additional call before the initial call
     has been completed and cached.

     Added in version 3.9.

 -- Function: @functools.cached_property (func)

     Transform a method of a class into a property whose value is
     computed once and then cached as a normal attribute for the life of
     the instance.  Similar to *note property(): 194, with the addition
     of caching.  Useful for expensive computed properties of instances
     that are otherwise effectively immutable.

     Example:

          class DataSet:

              def __init__(self, sequence_of_numbers):
                  self._data = tuple(sequence_of_numbers)

              @cached_property
              def stdev(self):
                  return statistics.stdev(self._data)

     The mechanics of ‘cached_property()’ are somewhat different from
     *note property(): 194.  A regular property blocks attribute writes
     unless a setter is defined.  In contrast, a 'cached_property'
     allows writes.

     The 'cached_property' decorator only runs on lookups and only when
     an attribute of the same name doesn’t exist.  When it does run, the
     'cached_property' writes to the attribute with the same name.
     Subsequent attribute reads and writes take precedence over the
     'cached_property' method and it works like a normal attribute.

     The cached value can be cleared by deleting the attribute.  This
     allows the 'cached_property' method to run again.

     The 'cached_property' does not prevent a possible race condition in
     multi-threaded usage.  The getter function could run more than once
     on the same instance, with the latest run setting the cached value.
     If the cached property is idempotent or otherwise not harmful to
     run more than once on an instance, this is fine.  If
     synchronization is needed, implement the necessary locking inside
     the decorated getter function or around the cached property access.

     Note, this decorator interferes with the operation of PEP 412(3)
     key-sharing dictionaries.  This means that instance dictionaries
     can take more space than usual.

     Also, this decorator requires that the ‘__dict__’ attribute on each
     instance be a mutable mapping.  This means it will not work with
     some types, such as metaclasses (since the ‘__dict__’ attributes on
     type instances are read-only proxies for the class namespace), and
     those that specify ‘__slots__’ without including ‘__dict__’ as one
     of the defined slots (as such classes don’t provide a ‘__dict__’
     attribute at all).

     If a mutable mapping is not available or if space-efficient key
     sharing is desired, an effect similar to ‘cached_property()’ can
     also be achieved by stacking *note property(): 194. on top of *note
     lru_cache(): 9fa.  See *note How do I cache method calls?: 2903.
     for more details on how this differs from ‘cached_property()’.

     Added in version 3.8.

     Changed in version 3.12: Prior to Python 3.12, ‘cached_property’
     included an undocumented lock to ensure that in multi-threaded
     usage the getter function was guaranteed to run only once per
     instance.  However, the lock was per-property, not per-instance,
     which could result in unacceptably high lock contention.  In Python
     3.12+ this locking is removed.

 -- Function: functools.cmp_to_key (func)

     Transform an old-style comparison function to a *note key function:
     e37.  Used with tools that accept key functions (such as *note
     sorted(): bed, *note min(): f3f, *note max(): f40, *note
     heapq.nlargest(): 26f3, *note heapq.nsmallest(): 26f4, *note
     itertools.groupby(): 15aa.).  This function is primarily used as a
     transition tool for programs being converted from Python 2 which
     supported the use of comparison functions.

     A comparison function is any callable that accepts two arguments,
     compares them, and returns a negative number for less-than, zero
     for equality, or a positive number for greater-than.  A key
     function is a callable that accepts one argument and returns
     another value to be used as the sort key.

     Example:

          sorted(iterable, key=cmp_to_key(locale.strcoll))  # locale-aware sort order

     For sorting examples and a brief sorting tutorial, see *note
     Sorting Techniques: 2337.

     Added in version 3.2.

 -- Function: @functools.lru_cache (user_function)

 -- Function: @functools.lru_cache (maxsize=128, typed=False)

     Decorator to wrap a function with a memoizing callable that saves
     up to the 'maxsize' most recent calls.  It can save time when an
     expensive or I/O bound function is periodically called with the
     same arguments.

     The cache is threadsafe so that the wrapped function can be used in
     multiple threads.  This means that the underlying data structure
     will remain coherent during concurrent updates.

     It is possible for the wrapped function to be called more than once
     if another thread makes an additional call before the initial call
     has been completed and cached.

     Since a dictionary is used to cache results, the positional and
     keyword arguments to the function must be *note hashable: 613.

     Distinct argument patterns may be considered to be distinct calls
     with separate cache entries.  For example, ‘f(a=1, b=2)’ and
     ‘f(b=2, a=1)’ differ in their keyword argument order and may have
     two separate cache entries.

     If 'user_function' is specified, it must be a callable.  This
     allows the 'lru_cache' decorator to be applied directly to a user
     function, leaving the 'maxsize' at its default value of 128:

          @lru_cache
          def count_vowels(sentence):
              return sum(sentence.count(vowel) for vowel in 'AEIOUaeiou')

     If 'maxsize' is set to ‘None’, the LRU feature is disabled and the
     cache can grow without bound.

     If 'typed' is set to true, function arguments of different types
     will be cached separately.  If 'typed' is false, the implementation
     will usually regard them as equivalent calls and only cache a
     single result.  (Some types such as 'str' and 'int' may be cached
     separately even when 'typed' is false.)

     Note, type specificity applies only to the function’s immediate
     arguments rather than their contents.  The scalar arguments,
     ‘Decimal(42)’ and ‘Fraction(42)’ are treated as distinct calls with
     distinct results.  In contrast, the tuple arguments ‘('answer',
     Decimal(42))’ and ‘('answer', Fraction(42))’ are treated as
     equivalent.

     The wrapped function is instrumented with a ‘cache_parameters()’
     function that returns a new *note dict: 256. showing the values for
     'maxsize' and 'typed'.  This is for information purposes only.
     Mutating the values has no effect.

     To help measure the effectiveness of the cache and tune the
     'maxsize' parameter, the wrapped function is instrumented with a
     ‘cache_info()’ function that returns a *note named tuple: 651.
     showing 'hits', 'misses', 'maxsize' and 'currsize'.

     The decorator also provides a ‘cache_clear()’ function for clearing
     or invalidating the cache.

     The original underlying function is accessible through the
     ‘__wrapped__’ attribute.  This is useful for introspection, for
     bypassing the cache, or for rewrapping the function with a
     different cache.

     The cache keeps references to the arguments and return values until
     they age out of the cache or until the cache is cleared.

     If a method is cached, the ‘self’ instance argument is included in
     the cache.  See *note How do I cache method calls?: 2903.

     An LRU (least recently used) cache(4) works best when the most
     recent calls are the best predictors of upcoming calls (for
     example, the most popular articles on a news server tend to change
     each day).  The cache’s size limit assures that the cache does not
     grow without bound on long-running processes such as web servers.

     In general, the LRU cache should only be used when you want to
     reuse previously computed values.  Accordingly, it doesn’t make
     sense to cache functions with side-effects, functions that need to
     create distinct mutable objects on each call (such as generators
     and async functions), or impure functions such as time() or
     random().

     Example of an LRU cache for static web content:

          @lru_cache(maxsize=32)
          def get_pep(num):
              'Retrieve text of a Python Enhancement Proposal'
              resource = f'https://peps.python.org/pep-{num:04d}'
              try:
                  with urllib.request.urlopen(resource) as s:
                      return s.read()
              except urllib.error.HTTPError:
                  return 'Not Found'

          >>> for n in 8, 290, 308, 320, 8, 218, 320, 279, 289, 320, 9991:
          ...     pep = get_pep(n)
          ...     print(n, len(pep))

          >>> get_pep.cache_info()
          CacheInfo(hits=3, misses=8, maxsize=32, currsize=8)

     Example of efficiently computing Fibonacci numbers(5) using a cache
     to implement a dynamic programming(6) technique:

          @lru_cache(maxsize=None)
          def fib(n):
              if n < 2:
                  return n
              return fib(n-1) + fib(n-2)

          >>> [fib(n) for n in range(16)]
          [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610]

          >>> fib.cache_info()
          CacheInfo(hits=28, misses=16, maxsize=None, currsize=16)

     Added in version 3.2.

     Changed in version 3.3: Added the 'typed' option.

     Changed in version 3.8: Added the 'user_function' option.

     Changed in version 3.9: Added the function ‘cache_parameters()’

 -- Function: @functools.total_ordering

     Given a class defining one or more rich comparison ordering
     methods, this class decorator supplies the rest.  This simplifies
     the effort involved in specifying all of the possible rich
     comparison operations:

     The class must define one of *note __lt__(): 12e7, *note __le__():
     1354, *note __gt__(): 1355, or *note __ge__(): 1356.  In addition,
     the class should supply an *note __eq__(): b13. method.

     For example:

          @total_ordering
          class Student:
              def _is_valid_operand(self, other):
                  return (hasattr(other, "lastname") and
                          hasattr(other, "firstname"))
              def __eq__(self, other):
                  if not self._is_valid_operand(other):
                      return NotImplemented
                  return ((self.lastname.lower(), self.firstname.lower()) ==
                          (other.lastname.lower(), other.firstname.lower()))
              def __lt__(self, other):
                  if not self._is_valid_operand(other):
                      return NotImplemented
                  return ((self.lastname.lower(), self.firstname.lower()) <
                          (other.lastname.lower(), other.firstname.lower()))

          Note: While this decorator makes it easy to create well
          behaved totally ordered types, it 'does' come at the cost of
          slower execution and more complex stack traces for the derived
          comparison methods.  If performance benchmarking indicates
          this is a bottleneck for a given application, implementing all
          six rich comparison methods instead is likely to provide an
          easy speed boost.

          Note: This decorator makes no attempt to override methods that
          have been declared in the class 'or its superclasses'.
          Meaning that if a superclass defines a comparison operator,
          'total_ordering' will not implement it again, even if the
          original method is abstract.

     Added in version 3.2.

     Changed in version 3.4: Returning ‘NotImplemented’ from the
     underlying comparison function for unrecognised types is now
     supported.

 -- Function: functools.partial (func, /, *args, **keywords)

     Return a new *note partial object: 2906. which when called will
     behave like 'func' called with the positional arguments 'args' and
     keyword arguments 'keywords'.  If more arguments are supplied to
     the call, they are appended to 'args'.  If additional keyword
     arguments are supplied, they extend and override 'keywords'.
     Roughly equivalent to:

          def partial(func, /, *args, **keywords):
              def newfunc(*fargs, **fkeywords):
                  newkeywords = {**keywords, **fkeywords}
                  return func(*args, *fargs, **newkeywords)
              newfunc.func = func
              newfunc.args = args
              newfunc.keywords = keywords
              return newfunc

     The ‘partial()’ is used for partial function application which
     “freezes” some portion of a function’s arguments and/or keywords
     resulting in a new object with a simplified signature.  For
     example, ‘partial()’ can be used to create a callable that behaves
     like the *note int(): 257. function where the 'base' argument
     defaults to two:

          >>> from functools import partial
          >>> basetwo = partial(int, base=2)
          >>> basetwo.__doc__ = 'Convert base 2 string to an int.'
          >>> basetwo('10010')
          18

 -- Class: functools.partialmethod (func, /, *args, **keywords)

     Return a new ‘partialmethod’ descriptor which behaves like *note
     partial: 417. except that it is designed to be used as a method
     definition rather than being directly callable.

     'func' must be a *note descriptor: 1677. or a callable (objects
     which are both, like normal functions, are handled as descriptors).

     When 'func' is a descriptor (such as a normal Python function,
     *note classmethod(): 166, *note staticmethod(): 419, *note
     abstractmethod(): 10c9. or another instance of ‘partialmethod’),
     calls to ‘__get__’ are delegated to the underlying descriptor, and
     an appropriate *note partial object: 2906. returned as the result.

     When 'func' is a non-descriptor callable, an appropriate bound
     method is created dynamically.  This behaves like a normal Python
     function when used as a method: the 'self' argument will be
     inserted as the first positional argument, even before the 'args'
     and 'keywords' supplied to the ‘partialmethod’ constructor.

     Example:

          >>> class Cell:
          ...     def __init__(self):
          ...         self._alive = False
          ...     @property
          ...     def alive(self):
          ...         return self._alive
          ...     def set_state(self, state):
          ...         self._alive = bool(state)
          ...     set_alive = partialmethod(set_state, True)
          ...     set_dead = partialmethod(set_state, False)
          ...
          >>> c = Cell()
          >>> c.alive
          False
          >>> c.set_alive()
          >>> c.alive
          True

     Added in version 3.4.

 -- Function: functools.reduce (function, iterable[, initial], /)

     Apply 'function' of two arguments cumulatively to the items of
     'iterable', from left to right, so as to reduce the iterable to a
     single value.  For example, ‘reduce(lambda x, y: x+y, [1, 2, 3, 4,
     5])’ calculates ‘((((1+2)+3)+4)+5)’.  The left argument, 'x', is
     the accumulated value and the right argument, 'y', is the update
     value from the 'iterable'.  If the optional 'initial' is present,
     it is placed before the items of the iterable in the calculation,
     and serves as a default when the iterable is empty.  If 'initial'
     is not given and 'iterable' contains only one item, the first item
     is returned.

     Roughly equivalent to:

          initial_missing = object()

          def reduce(function, iterable, initial=initial_missing, /):
              it = iter(iterable)
              if initial is initial_missing:
                  value = next(it)
              else:
                  value = initial
              for element in it:
                  value = function(value, element)
              return value

     See *note itertools.accumulate(): a08. for an iterator that yields
     all intermediate values.

 -- Function: @functools.singledispatch

     Transform a function into a *note single-dispatch: 9fd. *note
     generic function: 9fc.

     To define a generic function, decorate it with the
     ‘@singledispatch’ decorator.  When defining a function using
     ‘@singledispatch’, note that the dispatch happens on the type of
     the first argument:

          >>> from functools import singledispatch
          >>> @singledispatch
          ... def fun(arg, verbose=False):
          ...     if verbose:
          ...         print("Let me just say,", end=" ")
          ...     print(arg)

     To add overloaded implementations to the function, use the
     ‘register()’ attribute of the generic function, which can be used
     as a decorator.  For functions annotated with types, the decorator
     will infer the type of the first argument automatically:

          >>> @fun.register
          ... def _(arg: int, verbose=False):
          ...     if verbose:
          ...         print("Strength in numbers, eh?", end=" ")
          ...     print(arg)
          ...
          >>> @fun.register
          ... def _(arg: list, verbose=False):
          ...     if verbose:
          ...         print("Enumerate this:")
          ...     for i, elem in enumerate(arg):
          ...         print(i, elem)

     *note types.UnionType: 63d. and *note typing.Union: 63e. can also
     be used:

          >>> @fun.register
          ... def _(arg: int | float, verbose=False):
          ...     if verbose:
          ...         print("Strength in numbers, eh?", end=" ")
          ...     print(arg)
          ...
          >>> from typing import Union
          >>> @fun.register
          ... def _(arg: Union[list, set], verbose=False):
          ...     if verbose:
          ...         print("Enumerate this:")
          ...     for i, elem in enumerate(arg):
          ...         print(i, elem)
          ...

     For code which doesn’t use type annotations, the appropriate type
     argument can be passed explicitly to the decorator itself:

          >>> @fun.register(complex)
          ... def _(arg, verbose=False):
          ...     if verbose:
          ...         print("Better than complicated.", end=" ")
          ...     print(arg.real, arg.imag)
          ...

     For code that dispatches on a collections type (e.g., ‘list’), but
     wants to typehint the items of the collection (e.g., ‘list[int]’),
     the dispatch type should be passed explicitly to the decorator
     itself with the typehint going into the function definition:

          >>> @fun.register(list)
          ... def _(arg: list[int], verbose=False):
          ...     if verbose:
          ...         print("Enumerate this:")
          ...     for i, elem in enumerate(arg):
          ...         print(i, elem)

          Note: At runtime the function will dispatch on an instance of
          a list regardless of the type contained within the list i.e.
          ‘[1,2,3]’ will be dispatched the same as ‘["foo", "bar",
          "baz"]’.  The annotation provided in this example is for
          static type checkers only and has no runtime impact.

     To enable registering *note lambdas: 2908. and pre-existing
     functions, the *note register(): 2907. attribute can also be used
     in a functional form:

          >>> def nothing(arg, verbose=False):
          ...     print("Nothing.")
          ...
          >>> fun.register(type(None), nothing)

     The *note register(): 2907. attribute returns the undecorated
     function.  This enables decorator stacking, *note pickling: a6, and
     the creation of unit tests for each variant independently:

          >>> @fun.register(float)
          ... @fun.register(Decimal)
          ... def fun_num(arg, verbose=False):
          ...     if verbose:
          ...         print("Half of your number:", end=" ")
          ...     print(arg / 2)
          ...
          >>> fun_num is fun
          False

     When called, the generic function dispatches on the type of the
     first argument:

          >>> fun("Hello, world.")
          Hello, world.
          >>> fun("test.", verbose=True)
          Let me just say, test.
          >>> fun(42, verbose=True)
          Strength in numbers, eh? 42
          >>> fun(['spam', 'spam', 'eggs', 'spam'], verbose=True)
          Enumerate this:
          0 spam
          1 spam
          2 eggs
          3 spam
          >>> fun(None)
          Nothing.
          >>> fun(1.23)
          0.615

     Where there is no registered implementation for a specific type,
     its method resolution order is used to find a more generic
     implementation.  The original function decorated with
     ‘@singledispatch’ is registered for the base *note object: a9b.
     type, which means it is used if no better implementation is found.

     If an implementation is registered to an *note abstract base class:
     11fa, virtual subclasses of the base class will be dispatched to
     that implementation:

          >>> from collections.abc import Mapping
          >>> @fun.register
          ... def _(arg: Mapping, verbose=False):
          ...     if verbose:
          ...         print("Keys & Values")
          ...     for key, value in arg.items():
          ...         print(key, "=>", value)
          ...
          >>> fun({"a": "b"})
          a => b

     To check which implementation the generic function will choose for
     a given type, use the ‘dispatch()’ attribute:

          >>> fun.dispatch(float)
          <function fun_num at 0x1035a2840>
          >>> fun.dispatch(dict)    # note: default implementation
          <function fun at 0x103fe0000>

     To access all registered implementations, use the read-only
     ‘registry’ attribute:

          >>> fun.registry.keys()
          dict_keys([<class 'NoneType'>, <class 'int'>, <class 'object'>,
                    <class 'decimal.Decimal'>, <class 'list'>,
                    <class 'float'>])
          >>> fun.registry[float]
          <function fun_num at 0x1035a2840>
          >>> fun.registry[object]
          <function fun at 0x103fe0000>

     Added in version 3.4.

     Changed in version 3.7: The *note register(): 2907. attribute now
     supports using type annotations.

     Changed in version 3.11: The *note register(): 2907. attribute now
     supports *note types.UnionType: 63d. and *note typing.Union: 63e.
     as type annotations.

 -- Class: functools.singledispatchmethod (func)

     Transform a method into a *note single-dispatch: 9fd. *note generic
     function: 9fc.

     To define a generic method, decorate it with the
     ‘@singledispatchmethod’ decorator.  When defining a method using
     ‘@singledispatchmethod’, note that the dispatch happens on the type
     of the first non-'self' or non-'cls' argument:

          class Negator:
              @singledispatchmethod
              def neg(self, arg):
                  raise NotImplementedError("Cannot negate a")

              @neg.register
              def _(self, arg: int):
                  return -arg

              @neg.register
              def _(self, arg: bool):
                  return not arg

     ‘@singledispatchmethod’ supports nesting with other decorators such
     as *note @classmethod: 166.  Note that to allow for
     ‘dispatcher.register’, ‘singledispatchmethod’ must be the 'outer
     most' decorator.  Here is the ‘Negator’ class with the ‘neg’
     methods bound to the class, rather than an instance of the class:

          class Negator:
              @singledispatchmethod
              @classmethod
              def neg(cls, arg):
                  raise NotImplementedError("Cannot negate a")

              @neg.register
              @classmethod
              def _(cls, arg: int):
                  return -arg

              @neg.register
              @classmethod
              def _(cls, arg: bool):
                  return not arg

     The same pattern can be used for other similar decorators: *note
     @staticmethod: 419, *note @~abc.abstractmethod: 10c9, and others.

     Added in version 3.8.

 -- Function: functools.update_wrapper (wrapper, wrapped,
          assigned=WRAPPER_ASSIGNMENTS, updated=WRAPPER_UPDATES)

     Update a 'wrapper' function to look like the 'wrapped' function.
     The optional arguments are tuples to specify which attributes of
     the original function are assigned directly to the matching
     attributes on the wrapper function and which attributes of the
     wrapper function are updated with the corresponding attributes from
     the original function.  The default values for these arguments are
     the module level constants ‘WRAPPER_ASSIGNMENTS’ (which assigns to
     the wrapper function’s *note __module__: 20ad, *note __name__:
     131c, *note __qualname__: 20ac, *note __annotations__: 121d, *note
     __type_params__: 20af, and *note __doc__: 121e, the documentation
     string) and ‘WRAPPER_UPDATES’ (which updates the wrapper function’s
     *note __dict__: 131a, i.e.  the instance dictionary).

     To allow access to the original function for introspection and
     other purposes (e.g.  bypassing a caching decorator such as *note
     lru_cache(): 9fa.), this function automatically adds a
     ‘__wrapped__’ attribute to the wrapper that refers to the function
     being wrapped.

     The main intended use for this function is in *note decorator: 734.
     functions which wrap the decorated function and return the wrapper.
     If the wrapper function is not updated, the metadata of the
     returned function will reflect the wrapper definition rather than
     the original function definition, which is typically less than
     helpful.

     ‘update_wrapper()’ may be used with callables other than functions.
     Any attributes named in 'assigned' or 'updated' that are missing
     from the object being wrapped are ignored (i.e.  this function will
     not attempt to set them on the wrapper function).  *note
     AttributeError: 34e. is still raised if the wrapper function itself
     is missing any attributes named in 'updated'.

     Changed in version 3.2: The ‘__wrapped__’ attribute is now
     automatically added.  The *note __annotations__: 121d. attribute is
     now copied by default.  Missing attributes no longer trigger an
     *note AttributeError: 34e.

     Changed in version 3.4: The ‘__wrapped__’ attribute now always
     refers to the wrapped function, even if that function defined a
     ‘__wrapped__’ attribute.  (see bpo-17482(7))

     Changed in version 3.12: The *note __type_params__: 20af. attribute
     is now copied by default.

 -- Function: @functools.wraps (wrapped, assigned=WRAPPER_ASSIGNMENTS,
          updated=WRAPPER_UPDATES)

     This is a convenience function for invoking *note update_wrapper():
     105d. as a function decorator when defining a wrapper function.  It
     is equivalent to ‘partial(update_wrapper, wrapped=wrapped,
     assigned=assigned, updated=updated)’.  For example:

          >>> from functools import wraps
          >>> def my_decorator(f):
          ...     @wraps(f)
          ...     def wrapper(*args, **kwds):
          ...         print('Calling decorated function')
          ...         return f(*args, **kwds)
          ...     return wrapper
          ...
          >>> @my_decorator
          ... def example():
          ...     """Docstring"""
          ...     print('Called example function')
          ...
          >>> example()
          Calling decorated function
          Called example function
          >>> example.__name__
          'example'
          >>> example.__doc__
          'Docstring'

     Without the use of this decorator factory, the name of the example
     function would have been ‘'wrapper'’, and the docstring of the
     original ‘example()’ would have been lost.

* Menu:

* partial Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/functools.py

   (2) https://en.wikipedia.org/wiki/Memoization

   (3) https://peps.python.org/pep-0412/

   (4) 
https://en.wikipedia.org/wiki/Cache_replacement_policies#Least_Recently_Used_(LRU)

   (5) https://en.wikipedia.org/wiki/Fibonacci_number

   (6) https://en.wikipedia.org/wiki/Dynamic_programming

   (7) https://bugs.python.org/issue?@action=redirect&bpo=17482


File: python.info,  Node: partial Objects,  Up: functools — Higher-order functions and operations on callable objects

5.10.2.1 ‘partial’ Objects
..........................

*note partial: 417. objects are callable objects created by *note
partial(): 417.  They have three read-only attributes:

 -- Attribute: partial.func

     A callable object or function.  Calls to the *note partial: 417.
     object will be forwarded to *note func: 290a. with new arguments
     and keywords.

 -- Attribute: partial.args

     The leftmost positional arguments that will be prepended to the
     positional arguments provided to a *note partial: 417. object call.

 -- Attribute: partial.keywords

     The keyword arguments that will be supplied when the *note partial:
     417. object is called.

*note partial: 417. objects are like *note function objects: 299. in
that they are callable, weak referenceable, and can have attributes.
There are some important differences.  For instance, the *note __name__:
131c. and *note function.__doc__: 121e. attributes are not created
automatically.  Also, ‘partial’ objects defined in classes behave like
static methods and do not transform into bound methods during instance
attribute look-up.


File: python.info,  Node: operator — Standard operators as functions,  Prev: functools — Higher-order functions and operations on callable objects,  Up: Functional Programming Modules

5.10.3 ‘operator’ — Standard operators as functions
---------------------------------------------------

'Source code:' Lib/operator.py(1)

__________________________________________________________________

The ‘operator’ module exports a set of efficient functions corresponding
to the intrinsic operators of Python.  For example, ‘operator.add(x, y)’
is equivalent to the expression ‘x+y’.  Many function names are those
used for special methods, without the double underscores.  For backward
compatibility, many of these have a variant with the double underscores
kept.  The variants without the double underscores are preferred for
clarity.

The functions fall into categories that perform object comparisons,
logical operations, mathematical operations and sequence operations.

The object comparison functions are useful for all objects, and are
named after the rich comparison operators they support:

 -- Function: operator.lt (a, b)
 -- Function: operator.le (a, b)
 -- Function: operator.eq (a, b)
 -- Function: operator.ne (a, b)
 -- Function: operator.ge (a, b)
 -- Function: operator.gt (a, b)
 -- Function: operator.__lt__ (a, b)
 -- Function: operator.__le__ (a, b)
 -- Function: operator.__eq__ (a, b)
 -- Function: operator.__ne__ (a, b)
 -- Function: operator.__ge__ (a, b)
 -- Function: operator.__gt__ (a, b)

     Perform “rich comparisons” between 'a' and 'b'.  Specifically,
     ‘lt(a, b)’ is equivalent to ‘a < b’, ‘le(a, b)’ is equivalent to ‘a
     <= b’, ‘eq(a, b)’ is equivalent to ‘a == b’, ‘ne(a, b)’ is
     equivalent to ‘a != b’, ‘gt(a, b)’ is equivalent to ‘a > b’ and
     ‘ge(a, b)’ is equivalent to ‘a >= b’.  Note that these functions
     can return any value, which may or may not be interpretable as a
     Boolean value.  See *note Comparisons: 2228. for more information
     about rich comparisons.

The logical operations are also generally applicable to all objects, and
support truth tests, identity tests, and boolean operations:

 -- Function: operator.not_ (obj)
 -- Function: operator.__not__ (obj)

     Return the outcome of *note not: 2232. 'obj'.  (Note that there is
     no ‘__not__()’ method for object instances; only the interpreter
     core defines this operation.  The result is affected by the *note
     __bool__(): 131d. and *note __len__(): 15da. methods.)

 -- Function: operator.truth (obj)

     Return *note True: c2d. if 'obj' is true, and *note False: b4f.
     otherwise.  This is equivalent to using the *note bool: 46b.
     constructor.

 -- Function: operator.is_ (a, b)

     Return ‘a is b’.  Tests object identity.

 -- Function: operator.is_not (a, b)

     Return ‘a is not b’.  Tests object identity.

The mathematical and bitwise operations are the most numerous:

 -- Function: operator.abs (obj)
 -- Function: operator.__abs__ (obj)

     Return the absolute value of 'obj'.

 -- Function: operator.add (a, b)
 -- Function: operator.__add__ (a, b)

     Return ‘a + b’, for 'a' and 'b' numbers.

 -- Function: operator.and_ (a, b)
 -- Function: operator.__and__ (a, b)

     Return the bitwise and of 'a' and 'b'.

 -- Function: operator.floordiv (a, b)
 -- Function: operator.__floordiv__ (a, b)

     Return ‘a // b’.

 -- Function: operator.index (a)
 -- Function: operator.__index__ (a)

     Return 'a' converted to an integer.  Equivalent to ‘a.__index__()’.

     Changed in version 3.10: The result always has exact type *note
     int: 257.  Previously, the result could have been an instance of a
     subclass of ‘int’.

 -- Function: operator.inv (obj)
 -- Function: operator.invert (obj)
 -- Function: operator.__inv__ (obj)
 -- Function: operator.__invert__ (obj)

     Return the bitwise inverse of the number 'obj'.  This is equivalent
     to ‘~obj’.

 -- Function: operator.lshift (a, b)
 -- Function: operator.__lshift__ (a, b)

     Return 'a' shifted left by 'b'.

 -- Function: operator.mod (a, b)
 -- Function: operator.__mod__ (a, b)

     Return ‘a % b’.

 -- Function: operator.mul (a, b)
 -- Function: operator.__mul__ (a, b)

     Return ‘a * b’, for 'a' and 'b' numbers.

 -- Function: operator.matmul (a, b)
 -- Function: operator.__matmul__ (a, b)

     Return ‘a @ b’.

     Added in version 3.5.

 -- Function: operator.neg (obj)
 -- Function: operator.__neg__ (obj)

     Return 'obj' negated (‘-obj’).

 -- Function: operator.or_ (a, b)
 -- Function: operator.__or__ (a, b)

     Return the bitwise or of 'a' and 'b'.

 -- Function: operator.pos (obj)
 -- Function: operator.__pos__ (obj)

     Return 'obj' positive (‘+obj’).

 -- Function: operator.pow (a, b)
 -- Function: operator.__pow__ (a, b)

     Return ‘a ** b’, for 'a' and 'b' numbers.

 -- Function: operator.rshift (a, b)
 -- Function: operator.__rshift__ (a, b)

     Return 'a' shifted right by 'b'.

 -- Function: operator.sub (a, b)
 -- Function: operator.__sub__ (a, b)

     Return ‘a - b’.

 -- Function: operator.truediv (a, b)
 -- Function: operator.__truediv__ (a, b)

     Return ‘a / b’ where 2/3 is .66 rather than 0.  This is also known
     as “true” division.

 -- Function: operator.xor (a, b)
 -- Function: operator.__xor__ (a, b)

     Return the bitwise exclusive or of 'a' and 'b'.

Operations which work with sequences (some of them with mappings too)
include:

 -- Function: operator.concat (a, b)
 -- Function: operator.__concat__ (a, b)

     Return ‘a + b’ for 'a' and 'b' sequences.

 -- Function: operator.contains (a, b)
 -- Function: operator.__contains__ (a, b)

     Return the outcome of the test ‘b in a’.  Note the reversed
     operands.

 -- Function: operator.countOf (a, b)

     Return the number of occurrences of 'b' in 'a'.

 -- Function: operator.delitem (a, b)
 -- Function: operator.__delitem__ (a, b)

     Remove the value of 'a' at index 'b'.

 -- Function: operator.getitem (a, b)
 -- Function: operator.__getitem__ (a, b)

     Return the value of 'a' at index 'b'.

 -- Function: operator.indexOf (a, b)

     Return the index of the first of occurrence of 'b' in 'a'.

 -- Function: operator.setitem (a, b, c)
 -- Function: operator.__setitem__ (a, b, c)

     Set the value of 'a' at index 'b' to 'c'.

 -- Function: operator.length_hint (obj, default=0)

     Return an estimated length for the object 'obj'.  First try to
     return its actual length, then an estimate using *note
     object.__length_hint__(): f42, and finally return the default
     value.

     Added in version 3.4.

The following operation works with callables:

 -- Function: operator.call (obj, /, *args, **kwargs)
 -- Function: operator.__call__ (obj, /, *args, **kwargs)

     Return ‘obj(*args, **kwargs)’.

     Added in version 3.11.

The ‘operator’ module also defines tools for generalized attribute and
item lookups.  These are useful for making fast field extractors as
arguments for *note map(): 86a, *note sorted(): bed, *note
itertools.groupby(): 15aa, or other functions that expect a function
argument.

 -- Function: operator.attrgetter (attr)

 -- Function: operator.attrgetter (*attrs)

     Return a callable object that fetches 'attr' from its operand.  If
     more than one attribute is requested, returns a tuple of
     attributes.  The attribute names can also contain dots.  For
     example:

        * After ‘f = attrgetter('name')’, the call ‘f(b)’ returns
          ‘b.name’.

        * After ‘f = attrgetter('name', 'date')’, the call ‘f(b)’
          returns ‘(b.name, b.date)’.

        * After ‘f = attrgetter('name.first', 'name.last')’, the call
          ‘f(b)’ returns ‘(b.name.first, b.name.last)’.

     Equivalent to:

          def attrgetter(*items):
              if any(not isinstance(item, str) for item in items):
                  raise TypeError('attribute name must be a string')
              if len(items) == 1:
                  attr = items[0]
                  def g(obj):
                      return resolve_attr(obj, attr)
              else:
                  def g(obj):
                      return tuple(resolve_attr(obj, attr) for attr in items)
              return g

          def resolve_attr(obj, attr):
              for name in attr.split("."):
                  obj = getattr(obj, name)
              return obj

 -- Function: operator.itemgetter (item)

 -- Function: operator.itemgetter (*items)

     Return a callable object that fetches 'item' from its operand using
     the operand’s *note __getitem__(): 283. method.  If multiple items
     are specified, returns a tuple of lookup values.  For example:

        * After ‘f = itemgetter(2)’, the call ‘f(r)’ returns ‘r[2]’.

        * After ‘g = itemgetter(2, 5, 3)’, the call ‘g(r)’ returns
          ‘(r[2], r[5], r[3])’.

     Equivalent to:

          def itemgetter(*items):
              if len(items) == 1:
                  item = items[0]
                  def g(obj):
                      return obj[item]
              else:
                  def g(obj):
                      return tuple(obj[item] for item in items)
              return g

     The items can be any type accepted by the operand’s *note
     __getitem__(): 283. method.  Dictionaries accept any *note
     hashable: 613. value.  Lists, tuples, and strings accept an index
     or a slice:

          >>> itemgetter(1)('ABCDEFG')
          'B'
          >>> itemgetter(1, 3, 5)('ABCDEFG')
          ('B', 'D', 'F')
          >>> itemgetter(slice(2, None))('ABCDEFG')
          'CDEFG'
          >>> soldier = dict(rank='captain', name='dotterbart')
          >>> itemgetter('rank')(soldier)
          'captain'

     Example of using ‘itemgetter()’ to retrieve specific fields from a
     tuple record:

          >>> inventory = [('apple', 3), ('banana', 2), ('pear', 5), ('orange', 1)]
          >>> getcount = itemgetter(1)
          >>> list(map(getcount, inventory))
          [3, 2, 5, 1]
          >>> sorted(inventory, key=getcount)
          [('orange', 1), ('banana', 2), ('apple', 3), ('pear', 5)]

 -- Function: operator.methodcaller (name, /, *args, **kwargs)

     Return a callable object that calls the method 'name' on its
     operand.  If additional arguments and/or keyword arguments are
     given, they will be given to the method as well.  For example:

        * After ‘f = methodcaller('name')’, the call ‘f(b)’ returns
          ‘b.name()’.

        * After ‘f = methodcaller('name', 'foo', bar=1)’, the call
          ‘f(b)’ returns ‘b.name('foo', bar=1)’.

     Equivalent to:

          def methodcaller(name, /, *args, **kwargs):
              def caller(obj):
                  return getattr(obj, name)(*args, **kwargs)
              return caller

* Menu:

* Mapping Operators to Functions::
* In-place Operators::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/operator.py


File: python.info,  Node: Mapping Operators to Functions,  Next: In-place Operators,  Up: operator — Standard operators as functions

5.10.3.1 Mapping Operators to Functions
.......................................

This table shows how abstract operations correspond to operator symbols
in the Python syntax and the functions in the ‘operator’ module.

Operation                   Syntax                        Function
                                                          
------------------------------------------------------------------------------------------------------
                                                          
Addition                    ‘a + b’                       ‘add(a, b)’
                                                          
                                                          
Concatenation               ‘seq1 + seq2’                 ‘concat(seq1, seq2)’
                                                          
                                                          
Containment Test            ‘obj in seq’                  ‘contains(seq, obj)’
                                                          
                                                          
Division                    ‘a / b’                       ‘truediv(a, b)’
                                                          
                                                          
Division                    ‘a // b’                      ‘floordiv(a, b)’
                                                          
                                                          
Bitwise And                 ‘a & b’                       ‘and_(a, b)’
                                                          
                                                          
Bitwise Exclusive Or        ‘a ^ b’                       ‘xor(a, b)’
                                                          
                                                          
Bitwise Inversion           ‘~ a’                         ‘invert(a)’
                                                          
                                                          
Bitwise Or                  ‘a | b’                       ‘or_(a, b)’
                                                          
                                                          
Exponentiation              ‘a ** b’                      ‘pow(a, b)’
                                                          
                                                          
Identity                    ‘a is b’                      ‘is_(a, b)’
                                                          
                                                          
Identity                    ‘a is not b’                  ‘is_not(a, b)’
                                                          
                                                          
Indexed Assignment          ‘obj[k] = v’                  ‘setitem(obj, k, v)’
                                                          
                                                          
Indexed Deletion            ‘del obj[k]’                  ‘delitem(obj, k)’
                                                          
                                                          
Indexing                    ‘obj[k]’                      ‘getitem(obj, k)’
                                                          
                                                          
Left Shift                  ‘a << b’                      ‘lshift(a, b)’
                                                          
                                                          
Modulo                      ‘a % b’                       ‘mod(a, b)’
                                                          
                                                          
Multiplication              ‘a * b’                       ‘mul(a, b)’
                                                          
                                                          
Matrix Multiplication       ‘a @ b’                       ‘matmul(a, b)’
                                                          
                                                          
Negation (Arithmetic)       ‘- a’                         ‘neg(a)’
                                                          
                                                          
Negation (Logical)          ‘not a’                       ‘not_(a)’
                                                          
                                                          
Positive                    ‘+ a’                         ‘pos(a)’
                                                          
                                                          
Right Shift                 ‘a >> b’                      ‘rshift(a, b)’
                                                          
                                                          
Slice Assignment            ‘seq[i:j] = values’           ‘setitem(seq, slice(i, j), values)’
                                                          
                                                          
Slice Deletion              ‘del seq[i:j]’                ‘delitem(seq, slice(i, j))’
                                                          
                                                          
Slicing                     ‘seq[i:j]’                    ‘getitem(seq, slice(i, j))’
                                                          
                                                          
String Formatting           ‘s % obj’                     ‘mod(s, obj)’
                                                          
                                                          
Subtraction                 ‘a - b’                       ‘sub(a, b)’
                                                          
                                                          
Truth Test                  ‘obj’                         ‘truth(obj)’
                                                          
                                                          
Ordering                    ‘a < b’                       ‘lt(a, b)’
                                                          
                                                          
Ordering                    ‘a <= b’                      ‘le(a, b)’
                                                          
                                                          
Equality                    ‘a == b’                      ‘eq(a, b)’
                                                          
                                                          
Difference                  ‘a != b’                      ‘ne(a, b)’
                                                          
                                                          
Ordering                    ‘a >= b’                      ‘ge(a, b)’
                                                          
                                                          
Ordering                    ‘a > b’                       ‘gt(a, b)’
                                                          


File: python.info,  Node: In-place Operators,  Prev: Mapping Operators to Functions,  Up: operator — Standard operators as functions

5.10.3.2 In-place Operators
...........................

Many operations have an “in-place” version.  Listed below are functions
providing a more primitive access to in-place operators than the usual
syntax does; for example, the *note statement: 2951. ‘x += y’ is
equivalent to ‘x = operator.iadd(x, y)’.  Another way to put it is to
say that ‘z = operator.iadd(x, y)’ is equivalent to the compound
statement ‘z = x; z += y’.

In those examples, note that when an in-place method is called, the
computation and assignment are performed in two separate steps.  The
in-place functions listed below only do the first step, calling the
in-place method.  The second step, assignment, is not handled.

For immutable targets such as strings, numbers, and tuples, the updated
value is computed, but not assigned back to the input variable:

     >>> a = 'hello'
     >>> iadd(a, ' world')
     'hello world'
     >>> a
     'hello'

For mutable targets such as lists and dictionaries, the in-place method
will perform the update, so no subsequent assignment is necessary:

     >>> s = ['h', 'e', 'l', 'l', 'o']
     >>> iadd(s, [' ', 'w', 'o', 'r', 'l', 'd'])
     ['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']
     >>> s
     ['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd']

 -- Function: operator.iadd (a, b)
 -- Function: operator.__iadd__ (a, b)

     ‘a = iadd(a, b)’ is equivalent to ‘a += b’.

 -- Function: operator.iand (a, b)
 -- Function: operator.__iand__ (a, b)

     ‘a = iand(a, b)’ is equivalent to ‘a &= b’.

 -- Function: operator.iconcat (a, b)
 -- Function: operator.__iconcat__ (a, b)

     ‘a = iconcat(a, b)’ is equivalent to ‘a += b’ for 'a' and 'b'
     sequences.

 -- Function: operator.ifloordiv (a, b)
 -- Function: operator.__ifloordiv__ (a, b)

     ‘a = ifloordiv(a, b)’ is equivalent to ‘a //= b’.

 -- Function: operator.ilshift (a, b)
 -- Function: operator.__ilshift__ (a, b)

     ‘a = ilshift(a, b)’ is equivalent to ‘a <<= b’.

 -- Function: operator.imod (a, b)
 -- Function: operator.__imod__ (a, b)

     ‘a = imod(a, b)’ is equivalent to ‘a %= b’.

 -- Function: operator.imul (a, b)
 -- Function: operator.__imul__ (a, b)

     ‘a = imul(a, b)’ is equivalent to ‘a *= b’.

 -- Function: operator.imatmul (a, b)
 -- Function: operator.__imatmul__ (a, b)

     ‘a = imatmul(a, b)’ is equivalent to ‘a @= b’.

     Added in version 3.5.

 -- Function: operator.ior (a, b)
 -- Function: operator.__ior__ (a, b)

     ‘a = ior(a, b)’ is equivalent to ‘a |= b’.

 -- Function: operator.ipow (a, b)
 -- Function: operator.__ipow__ (a, b)

     ‘a = ipow(a, b)’ is equivalent to ‘a **= b’.

 -- Function: operator.irshift (a, b)
 -- Function: operator.__irshift__ (a, b)

     ‘a = irshift(a, b)’ is equivalent to ‘a >>= b’.

 -- Function: operator.isub (a, b)
 -- Function: operator.__isub__ (a, b)

     ‘a = isub(a, b)’ is equivalent to ‘a -= b’.

 -- Function: operator.itruediv (a, b)
 -- Function: operator.__itruediv__ (a, b)

     ‘a = itruediv(a, b)’ is equivalent to ‘a /= b’.

 -- Function: operator.ixor (a, b)
 -- Function: operator.__ixor__ (a, b)

     ‘a = ixor(a, b)’ is equivalent to ‘a ^= b’.


File: python.info,  Node: File and Directory Access,  Next: Data Persistence,  Prev: Functional Programming Modules,  Up: The Python Standard Library

5.11 File and Directory Access
==============================

The modules described in this chapter deal with disk files and
directories.  For example, there are modules for reading the properties
of files, manipulating paths in a portable way, and creating temporary
files.  The full list of modules in this chapter is:

* Menu:

* pathlib — Object-oriented filesystem paths::
* os.path — Common pathname manipulations: os path — Common pathname manipulations.
* stat — Interpreting stat() results: stat — Interpreting stat results.
* filecmp — File and Directory Comparisons::
* tempfile — Generate temporary files and directories::
* glob — Unix style pathname pattern expansion::
* fnmatch — Unix filename pattern matching::
* linecache — Random access to text lines::
* shutil — High-level file operations::


File: python.info,  Node: pathlib — Object-oriented filesystem paths,  Next: os path — Common pathname manipulations,  Up: File and Directory Access

5.11.1 ‘pathlib’ — Object-oriented filesystem paths
---------------------------------------------------

Added in version 3.4.

'Source code:' Lib/pathlib/(1)

__________________________________________________________________

This module offers classes representing filesystem paths with semantics
appropriate for different operating systems.  Path classes are divided
between *note pure paths: 2973, which provide purely computational
operations without I/O, and *note concrete paths: 2974, which inherit
from pure paths but also provide I/O operations.

[image src="python-figures/pathlib-inheritance.png" alt="Inheritance diagram showing the classes available in pathlib. The most basic class is PurePath, which has three direct subclasses: PurePosixPath, PureWindowsPath, and Path. Further to these four classes, there are two classes that use multiple inheritance: PosixPath subclasses PurePosixPath and Path, and WindowsPath subclasses PureWindowsPath and Path."]


If you’ve never used this module before or just aren’t sure which class
is right for your task, *note Path: 229. is most likely what you need.
It instantiates a *note concrete path: 2974. for the platform the code
is running on.

Pure paths are useful in some special cases; for example:

  1. If you want to manipulate Windows paths on a Unix machine (or vice
     versa).  You cannot instantiate a *note WindowsPath: 2975. when
     running on Unix, but you can instantiate *note PureWindowsPath:
     1814.

  2. You want to make sure that your code only manipulates paths without
     actually accessing the OS. In this case, instantiating one of the
     pure classes may be useful since those simply don’t have any
     OS-accessing operations.

See also
........

PEP 428(2): The pathlib module – object-oriented filesystem paths.

See also
........

For low-level path manipulation on strings, you can also use the *note
os.path: a2. module.

* Menu:

* Basic use::
* Exceptions: Exceptions<6>.
* Pure paths::
* Concrete paths::
* Pattern language::
* Comparison to the glob module::
* Comparison to the os and os.path modules: Comparison to the os and os path modules.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pathlib/

   (2) https://peps.python.org/pep-0428/


File: python.info,  Node: Basic use,  Next: Exceptions<6>,  Up: pathlib — Object-oriented filesystem paths

5.11.1.1 Basic use
..................

Importing the main class:

     >>> from pathlib import Path

Listing subdirectories:

     >>> p = Path('.')
     >>> [x for x in p.iterdir() if x.is_dir()]
     [PosixPath('.hg'), PosixPath('docs'), PosixPath('dist'),
      PosixPath('__pycache__'), PosixPath('build')]

Listing Python source files in this directory tree:

     >>> list(p.glob('**/*.py'))
     [PosixPath('test_pathlib.py'), PosixPath('setup.py'),
      PosixPath('pathlib.py'), PosixPath('docs/conf.py'),
      PosixPath('build/lib/pathlib.py')]

Navigating inside a directory tree:

     >>> p = Path('/etc')
     >>> q = p / 'init.d' / 'reboot'
     >>> q
     PosixPath('/etc/init.d/reboot')
     >>> q.resolve()
     PosixPath('/etc/rc.d/init.d/halt')

Querying path properties:

     >>> q.exists()
     True
     >>> q.is_dir()
     False

Opening a file:

     >>> with q.open() as f: f.readline()
     ...
     '#!/bin/bash\n'


File: python.info,  Node: Exceptions<6>,  Next: Pure paths,  Prev: Basic use,  Up: pathlib — Object-oriented filesystem paths

5.11.1.2 Exceptions
...................

 -- Exception: pathlib.UnsupportedOperation

     An exception inheriting *note NotImplementedError: 228. that is
     raised when an unsupported operation is called on a path object.

     Added in version 3.13.


File: python.info,  Node: Pure paths,  Next: Concrete paths,  Prev: Exceptions<6>,  Up: pathlib — Object-oriented filesystem paths

5.11.1.3 Pure paths
...................

Pure path objects provide path-handling operations which don’t actually
access a filesystem.  There are three ways to access these classes,
which we also call 'flavours':

 -- Class: pathlib.PurePath (*pathsegments)

     A generic class that represents the system’s path flavour
     (instantiating it creates either a *note PurePosixPath: 2979. or a
     *note PureWindowsPath: 1814.):

          >>> PurePath('setup.py')      # Running on a Unix machine
          PurePosixPath('setup.py')

     Each element of 'pathsegments' can be either a string representing
     a path segment, or an object implementing the *note os.PathLike:
     c72. interface where the *note __fspath__(): c73. method returns a
     string, such as another path object:

          >>> PurePath('foo', 'some/path', 'bar')
          PurePosixPath('foo/some/path/bar')
          >>> PurePath(Path('foo'), Path('bar'))
          PurePosixPath('foo/bar')

     When 'pathsegments' is empty, the current directory is assumed:

          >>> PurePath()
          PurePosixPath('.')

     If a segment is an absolute path, all previous segments are ignored
     (like *note os.path.join(): 173c.):

          >>> PurePath('/etc', '/usr', 'lib64')
          PurePosixPath('/usr/lib64')
          >>> PureWindowsPath('c:/Windows', 'd:bar')
          PureWindowsPath('d:bar')

     On Windows, the drive is not reset when a rooted relative path
     segment (e.g., ‘r'\foo'’) is encountered:

          >>> PureWindowsPath('c:/Windows', '/Program Files')
          PureWindowsPath('c:/Program Files')

     Spurious slashes and single dots are collapsed, but double dots
     (‘'..'’) and leading double slashes (‘'//'’) are not, since this
     would change the meaning of a path for various reasons (e.g.
     symbolic links, UNC paths):

          >>> PurePath('foo//bar')
          PurePosixPath('foo/bar')
          >>> PurePath('//foo/bar')
          PurePosixPath('//foo/bar')
          >>> PurePath('foo/./bar')
          PurePosixPath('foo/bar')
          >>> PurePath('foo/../bar')
          PurePosixPath('foo/../bar')

     (a naïve approach would make ‘PurePosixPath('foo/../bar')’
     equivalent to ‘PurePosixPath('bar')’, which is wrong if ‘foo’ is a
     symbolic link to another directory)

     Pure path objects implement the *note os.PathLike: c72. interface,
     allowing them to be used anywhere the interface is accepted.

     Changed in version 3.6: Added support for the *note os.PathLike:
     c72. interface.

 -- Class: pathlib.PurePosixPath (*pathsegments)

     A subclass of *note PurePath: 4a9, this path flavour represents
     non-Windows filesystem paths:

          >>> PurePosixPath('/etc/hosts')
          PurePosixPath('/etc/hosts')

     'pathsegments' is specified similarly to *note PurePath: 4a9.

 -- Class: pathlib.PureWindowsPath (*pathsegments)

     A subclass of *note PurePath: 4a9, this path flavour represents
     Windows filesystem paths, including UNC paths(1):

          >>> PureWindowsPath('c:/', 'Users', 'Ximénez')
          PureWindowsPath('c:/Users/Ximénez')
          >>> PureWindowsPath('//server/share/file')
          PureWindowsPath('//server/share/file')

     'pathsegments' is specified similarly to *note PurePath: 4a9.

Regardless of the system you’re running on, you can instantiate all of
these classes, since they don’t provide any operation that does system
calls.

* Menu:

* General properties::
* Operators: Operators<2>.
* Accessing individual parts::
* Methods and properties::

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Path_(computing)#UNC


File: python.info,  Node: General properties,  Next: Operators<2>,  Up: Pure paths

5.11.1.4 General properties
...........................

Paths are immutable and *note hashable: 613.  Paths of a same flavour
are comparable and orderable.  These properties respect the flavour’s
case-folding semantics:

     >>> PurePosixPath('foo') == PurePosixPath('FOO')
     False
     >>> PureWindowsPath('foo') == PureWindowsPath('FOO')
     True
     >>> PureWindowsPath('FOO') in { PureWindowsPath('foo') }
     True
     >>> PureWindowsPath('C:') < PureWindowsPath('d:')
     True

Paths of a different flavour compare unequal and cannot be ordered:

     >>> PureWindowsPath('foo') == PurePosixPath('foo')
     False
     >>> PureWindowsPath('foo') < PurePosixPath('foo')
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: '<' not supported between instances of 'PureWindowsPath' and 'PurePosixPath'


File: python.info,  Node: Operators<2>,  Next: Accessing individual parts,  Prev: General properties,  Up: Pure paths

5.11.1.5 Operators
..................

The slash operator helps create child paths, like *note os.path.join():
173c.  If the argument is an absolute path, the previous path is
ignored.  On Windows, the drive is not reset when the argument is a
rooted relative path (e.g., ‘r'\foo'’):

     >>> p = PurePath('/etc')
     >>> p
     PurePosixPath('/etc')
     >>> p / 'init.d' / 'apache2'
     PurePosixPath('/etc/init.d/apache2')
     >>> q = PurePath('bin')
     >>> '/usr' / q
     PurePosixPath('/usr/bin')
     >>> p / '/an_absolute_path'
     PurePosixPath('/an_absolute_path')
     >>> PureWindowsPath('c:/Windows', '/Program Files')
     PureWindowsPath('c:/Program Files')

A path object can be used anywhere an object implementing *note
os.PathLike: c72. is accepted:

     >>> import os
     >>> p = PurePath('/etc')
     >>> os.fspath(p)
     '/etc'

The string representation of a path is the raw filesystem path itself
(in native form, e.g.  with backslashes under Windows), which you can
pass to any function taking a file path as a string:

     >>> p = PurePath('/etc')
     >>> str(p)
     '/etc'
     >>> p = PureWindowsPath('c:/Program Files')
     >>> str(p)
     'c:\\Program Files'

Similarly, calling *note bytes: 1c2. on a path gives the raw filesystem
path as a bytes object, as encoded by *note os.fsencode(): c76.:

     >>> bytes(p)
     b'/etc'

     Note: Calling *note bytes: 1c2. is only recommended under Unix.
     Under Windows, the unicode form is the canonical representation of
     filesystem paths.


File: python.info,  Node: Accessing individual parts,  Next: Methods and properties,  Prev: Operators<2>,  Up: Pure paths

5.11.1.6 Accessing individual parts
...................................

To access the individual “parts” (components) of a path, use the
following property:

 -- Attribute: PurePath.parts

     A tuple giving access to the path’s various components:

          >>> p = PurePath('/usr/bin/python3')
          >>> p.parts
          ('/', 'usr', 'bin', 'python3')

          >>> p = PureWindowsPath('c:/Program Files/PSF')
          >>> p.parts
          ('c:\\', 'Program Files', 'PSF')

     (note how the drive and local root are regrouped in a single part)


File: python.info,  Node: Methods and properties,  Prev: Accessing individual parts,  Up: Pure paths

5.11.1.7 Methods and properties
...............................

Pure paths provide the following methods and properties:

 -- Attribute: PurePath.parser

     The implementation of the *note os.path: a2. module used for
     low-level path parsing and joining: either ‘posixpath’ or ‘ntpath’.

     Added in version 3.13.

 -- Attribute: PurePath.drive

     A string representing the drive letter or name, if any:

          >>> PureWindowsPath('c:/Program Files/').drive
          'c:'
          >>> PureWindowsPath('/Program Files/').drive
          ''
          >>> PurePosixPath('/etc').drive
          ''

     UNC shares are also considered drives:

          >>> PureWindowsPath('//host/share/foo.txt').drive
          '\\\\host\\share'

 -- Attribute: PurePath.root

     A string representing the (local or global) root, if any:

          >>> PureWindowsPath('c:/Program Files/').root
          '\\'
          >>> PureWindowsPath('c:Program Files/').root
          ''
          >>> PurePosixPath('/etc').root
          '/'

     UNC shares always have a root:

          >>> PureWindowsPath('//host/share').root
          '\\'

     If the path starts with more than two successive slashes, *note
     PurePosixPath: 2979. collapses them:

          >>> PurePosixPath('//etc').root
          '//'
          >>> PurePosixPath('///etc').root
          '/'
          >>> PurePosixPath('////etc').root
          '/'

          Note: This behavior conforms to 'The Open Group Base
          Specifications Issue 6', paragraph 4.11 Pathname
          Resolution(1):

          '“A pathname that begins with two successive slashes may be
          interpreted in an implementation-defined manner, although more
          than two leading slashes shall be treated as a single slash.”'

 -- Attribute: PurePath.anchor

     The concatenation of the drive and root:

          >>> PureWindowsPath('c:/Program Files/').anchor
          'c:\\'
          >>> PureWindowsPath('c:Program Files/').anchor
          'c:'
          >>> PurePosixPath('/etc').anchor
          '/'
          >>> PureWindowsPath('//host/share').anchor
          '\\\\host\\share\\'

 -- Attribute: PurePath.parents

     An immutable sequence providing access to the logical ancestors of
     the path:

          >>> p = PureWindowsPath('c:/foo/bar/setup.py')
          >>> p.parents[0]
          PureWindowsPath('c:/foo/bar')
          >>> p.parents[1]
          PureWindowsPath('c:/foo')
          >>> p.parents[2]
          PureWindowsPath('c:/')

     Changed in version 3.10: The parents sequence now supports *note
     slices: 2336. and negative index values.

 -- Attribute: PurePath.parent

     The logical parent of the path:

          >>> p = PurePosixPath('/a/b/c/d')
          >>> p.parent
          PurePosixPath('/a/b/c')

     You cannot go past an anchor, or empty path:

          >>> p = PurePosixPath('/')
          >>> p.parent
          PurePosixPath('/')
          >>> p = PurePosixPath('.')
          >>> p.parent
          PurePosixPath('.')

          Note: This is a purely lexical operation, hence the following
          behaviour:

               >>> p = PurePosixPath('foo/..')
               >>> p.parent
               PurePosixPath('foo')

          If you want to walk an arbitrary filesystem path upwards, it
          is recommended to first call *note Path.resolve(): 180c. so as
          to resolve symlinks and eliminate ‘".."’ components.

 -- Attribute: PurePath.name

     A string representing the final path component, excluding the drive
     and root, if any:

          >>> PurePosixPath('my/library/setup.py').name
          'setup.py'

     UNC drive names are not considered:

          >>> PureWindowsPath('//some/share/setup.py').name
          'setup.py'
          >>> PureWindowsPath('//some/share').name
          ''

 -- Attribute: PurePath.suffix

     The last dot-separated portion of the final component, if any:

          >>> PurePosixPath('my/library/setup.py').suffix
          '.py'
          >>> PurePosixPath('my/library.tar.gz').suffix
          '.gz'
          >>> PurePosixPath('my/library').suffix
          ''

     This is commonly called the file extension.

 -- Attribute: PurePath.suffixes

     A list of the path’s suffixes, often called file extensions:

          >>> PurePosixPath('my/library.tar.gar').suffixes
          ['.tar', '.gar']
          >>> PurePosixPath('my/library.tar.gz').suffixes
          ['.tar', '.gz']
          >>> PurePosixPath('my/library').suffixes
          []

 -- Attribute: PurePath.stem

     The final path component, without its suffix:

          >>> PurePosixPath('my/library.tar.gz').stem
          'library.tar'
          >>> PurePosixPath('my/library.tar').stem
          'library'
          >>> PurePosixPath('my/library').stem
          'library'

 -- Method: PurePath.as_posix ()

     Return a string representation of the path with forward slashes
     (‘/’):

          >>> p = PureWindowsPath('c:\\windows')
          >>> str(p)
          'c:\\windows'
          >>> p.as_posix()
          'c:/windows'

 -- Method: PurePath.is_absolute ()

     Return whether the path is absolute or not.  A path is considered
     absolute if it has both a root and (if the flavour allows) a drive:

          >>> PurePosixPath('/a/b').is_absolute()
          True
          >>> PurePosixPath('a/b').is_absolute()
          False

          >>> PureWindowsPath('c:/a/b').is_absolute()
          True
          >>> PureWindowsPath('/a/b').is_absolute()
          False
          >>> PureWindowsPath('c:').is_absolute()
          False
          >>> PureWindowsPath('//some/share').is_absolute()
          True

 -- Method: PurePath.is_relative_to (other)

     Return whether or not this path is relative to the 'other' path.

          >>> p = PurePath('/etc/passwd')
          >>> p.is_relative_to('/etc')
          True
          >>> p.is_relative_to('/usr')
          False

     This method is string-based; it neither accesses the filesystem nor
     treats “‘..’” segments specially.  The following code is
     equivalent:

          >>> u = PurePath('/usr')
          >>> u == p or u in p.parents
          False

     Added in version 3.9.

     Deprecated since version 3.12, will be removed in version 3.14:
     Passing additional arguments is deprecated; if supplied, they are
     joined with 'other'.

 -- Method: PurePath.is_reserved ()

     With *note PureWindowsPath: 1814, return ‘True’ if the path is
     considered reserved under Windows, ‘False’ otherwise.  With *note
     PurePosixPath: 2979, ‘False’ is always returned.

     Changed in version 3.13: Windows path names that contain a colon,
     or end with a dot or a space, are considered reserved.  UNC paths
     may be reserved.

     Deprecated since version 3.13, will be removed in version 3.15:
     This method is deprecated; use *note os.path.isreserved(): 223. to
     detect reserved paths on Windows.

 -- Method: PurePath.joinpath (*pathsegments)

     Calling this method is equivalent to combining the path with each
     of the given 'pathsegments' in turn:

          >>> PurePosixPath('/etc').joinpath('passwd')
          PurePosixPath('/etc/passwd')
          >>> PurePosixPath('/etc').joinpath(PurePosixPath('passwd'))
          PurePosixPath('/etc/passwd')
          >>> PurePosixPath('/etc').joinpath('init.d', 'apache2')
          PurePosixPath('/etc/init.d/apache2')
          >>> PureWindowsPath('c:').joinpath('/Program Files')
          PureWindowsPath('c:/Program Files')

 -- Method: PurePath.full_match (pattern, *, case_sensitive=None)

     Match this path against the provided glob-style pattern.  Return
     ‘True’ if matching is successful, ‘False’ otherwise.  For example:

          >>> PurePath('a/b.py').full_match('a/*.py')
          True
          >>> PurePath('a/b.py').full_match('*.py')
          False
          >>> PurePath('/a/b/c.py').full_match('/a/**')
          True
          >>> PurePath('/a/b/c.py').full_match('**/*.py')
          True

     See also
     ........

     *note Pattern language: 2988. documentation.

     As with other methods, case-sensitivity follows platform defaults:

          >>> PurePosixPath('b.py').full_match('*.PY')
          False
          >>> PureWindowsPath('b.py').full_match('*.PY')
          True

     Set 'case_sensitive' to ‘True’ or ‘False’ to override this
     behaviour.

     Added in version 3.13.

 -- Method: PurePath.match (pattern, *, case_sensitive=None)

     Match this path against the provided non-recursive glob-style
     pattern.  Return ‘True’ if matching is successful, ‘False’
     otherwise.

     This method is similar to *note full_match(): 22b, but empty
     patterns aren’t allowed (*note ValueError: 202. is raised), the
     recursive wildcard “‘**’” isn’t supported (it acts like
     non-recursive “‘*’”), and if a relative pattern is provided, then
     matching is done from the right:

          >>> PurePath('a/b.py').match('*.py')
          True
          >>> PurePath('/a/b/c.py').match('b/*.py')
          True
          >>> PurePath('/a/b/c.py').match('a/*.py')
          False

     Changed in version 3.12: The 'pattern' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.12: The 'case_sensitive' parameter was added.

 -- Method: PurePath.relative_to (other, walk_up=False)

     Compute a version of this path relative to the path represented by
     'other'.  If it’s impossible, *note ValueError: 202. is raised:

          >>> p = PurePosixPath('/etc/passwd')
          >>> p.relative_to('/')
          PurePosixPath('etc/passwd')
          >>> p.relative_to('/etc')
          PurePosixPath('passwd')
          >>> p.relative_to('/usr')
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "pathlib.py", line 941, in relative_to
              raise ValueError(error_message.format(str(self), str(formatted)))
          ValueError: '/etc/passwd' is not in the subpath of '/usr' OR one path is relative and the other is absolute.

     When 'walk_up' is false (the default), the path must start with
     'other'.  When the argument is true, ‘..’ entries may be added to
     form the relative path.  In all other cases, such as the paths
     referencing different drives, *note ValueError: 202. is raised.:

          >>> p.relative_to('/usr', walk_up=True)
          PurePosixPath('../etc/passwd')
          >>> p.relative_to('foo', walk_up=True)
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "pathlib.py", line 941, in relative_to
              raise ValueError(error_message.format(str(self), str(formatted)))
          ValueError: '/etc/passwd' is not on the same drive as 'foo' OR one path is relative and the other is absolute.

          Warning: This function is part of *note PurePath: 4a9. and
          works with strings.  It does not check or access the
          underlying file structure.  This can impact the 'walk_up'
          option as it assumes that no symlinks are present in the path;
          call *note resolve(): 180c. first if necessary to resolve
          symlinks.

     Changed in version 3.12: The 'walk_up' parameter was added (old
     behavior is the same as ‘walk_up=False’).

     Deprecated since version 3.12, will be removed in version 3.14:
     Passing additional positional arguments is deprecated; if supplied,
     they are joined with 'other'.

 -- Method: PurePath.with_name (name)

     Return a new path with the *note name: 2982. changed.  If the
     original path doesn’t have a name, ValueError is raised:

          >>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
          >>> p.with_name('setup.py')
          PureWindowsPath('c:/Downloads/setup.py')
          >>> p = PureWindowsPath('c:/')
          >>> p.with_name('setup.py')
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "/home/antoine/cpython/default/Lib/pathlib.py", line 751, in with_name
              raise ValueError("%r has an empty name" % (self,))
          ValueError: PureWindowsPath('c:/') has an empty name

 -- Method: PurePath.with_stem (stem)

     Return a new path with the *note stem: 2985. changed.  If the
     original path doesn’t have a name, ValueError is raised:

          >>> p = PureWindowsPath('c:/Downloads/draft.txt')
          >>> p.with_stem('final')
          PureWindowsPath('c:/Downloads/final.txt')
          >>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
          >>> p.with_stem('lib')
          PureWindowsPath('c:/Downloads/lib.gz')
          >>> p = PureWindowsPath('c:/')
          >>> p.with_stem('')
          Traceback (most recent call last):
            File "<stdin>", line 1, in <module>
            File "/home/antoine/cpython/default/Lib/pathlib.py", line 861, in with_stem
              return self.with_name(stem + self.suffix)
            File "/home/antoine/cpython/default/Lib/pathlib.py", line 851, in with_name
              raise ValueError("%r has an empty name" % (self,))
          ValueError: PureWindowsPath('c:/') has an empty name

     Added in version 3.9.

 -- Method: PurePath.with_suffix (suffix)

     Return a new path with the *note suffix: 2983. changed.  If the
     original path doesn’t have a suffix, the new 'suffix' is appended
     instead.  If the 'suffix' is an empty string, the original suffix
     is removed:

          >>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
          >>> p.with_suffix('.bz2')
          PureWindowsPath('c:/Downloads/pathlib.tar.bz2')
          >>> p = PureWindowsPath('README')
          >>> p.with_suffix('.txt')
          PureWindowsPath('README.txt')
          >>> p = PureWindowsPath('README.txt')
          >>> p.with_suffix('')
          PureWindowsPath('README')

 -- Method: PurePath.with_segments (*pathsegments)

     Create a new path object of the same type by combining the given
     'pathsegments'.  This method is called whenever a derivative path
     is created, such as from *note parent: 183d. and *note
     relative_to(): 2ca.  Subclasses may override this method to pass
     information to derivative paths, for example:

          from pathlib import PurePosixPath

          class MyPath(PurePosixPath):
              def __init__(self, *pathsegments, session_id):
                  super().__init__(*pathsegments)
                  self.session_id = session_id

              def with_segments(self, *pathsegments):
                  return type(self)(*pathsegments, session_id=self.session_id)

          etc = MyPath('/etc', session_id=42)
          hosts = etc / 'hosts'
          print(hosts.session_id)  # 42

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) 
https://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_11


File: python.info,  Node: Concrete paths,  Next: Pattern language,  Prev: Pure paths,  Up: pathlib — Object-oriented filesystem paths

5.11.1.8 Concrete paths
.......................

Concrete paths are subclasses of the pure path classes.  In addition to
operations provided by the latter, they also provide methods to do
system calls on path objects.  There are three ways to instantiate
concrete paths:

 -- Class: pathlib.Path (*pathsegments)

     A subclass of *note PurePath: 4a9, this class represents concrete
     paths of the system’s path flavour (instantiating it creates either
     a *note PosixPath: 298a. or a *note WindowsPath: 2975.):

          >>> Path('setup.py')
          PosixPath('setup.py')

     'pathsegments' is specified similarly to *note PurePath: 4a9.

 -- Class: pathlib.PosixPath (*pathsegments)

     A subclass of *note Path: 229. and *note PurePosixPath: 2979, this
     class represents concrete non-Windows filesystem paths:

          >>> PosixPath('/etc/hosts')
          PosixPath('/etc/hosts')

     'pathsegments' is specified similarly to *note PurePath: 4a9.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. on
     Windows.  In previous versions, *note NotImplementedError: 228. was
     raised instead.

 -- Class: pathlib.WindowsPath (*pathsegments)

     A subclass of *note Path: 229. and *note PureWindowsPath: 1814,
     this class represents concrete Windows filesystem paths:

          >>> WindowsPath('c:/', 'Users', 'Ximénez')
          WindowsPath('c:/Users/Ximénez')

     'pathsegments' is specified similarly to *note PurePath: 4a9.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. on
     non-Windows platforms.  In previous versions, *note
     NotImplementedError: 228. was raised instead.

You can only instantiate the class flavour that corresponds to your
system (allowing system calls on non-compatible path flavours could lead
to bugs or failures in your application):

     >>> import os
     >>> os.name
     'posix'
     >>> Path('setup.py')
     PosixPath('setup.py')
     >>> PosixPath('setup.py')
     PosixPath('setup.py')
     >>> WindowsPath('setup.py')
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "pathlib.py", line 798, in __new__
         % (cls.__name__,))
     UnsupportedOperation: cannot instantiate 'WindowsPath' on your system

Some concrete path methods can raise an *note OSError: 41a. if a system
call fails (for example because the path doesn’t exist).

* Menu:

* Parsing and generating URIs::
* Expanding and resolving paths::
* Querying file type and status::
* Reading and writing files::
* Reading directories::
* Creating files and directories::
* Renaming and deleting::
* Permissions and ownership::


File: python.info,  Node: Parsing and generating URIs,  Next: Expanding and resolving paths,  Up: Concrete paths

5.11.1.9 Parsing and generating URIs
....................................

Concrete path objects can be created from, and represented as, ‘file’
URIs conforming to RFC 8089(1).

     Note: File URIs are not portable across machines with different
     *note filesystem encodings: 298c.

 -- Method: classmethod Path.from_uri (uri)

     Return a new path object from parsing a ‘file’ URI. For example:

          >>> p = Path.from_uri('file:///etc/hosts')
          PosixPath('/etc/hosts')

     On Windows, DOS device and UNC paths may be parsed from URIs:

          >>> p = Path.from_uri('file:///c:/windows')
          WindowsPath('c:/windows')
          >>> p = Path.from_uri('file://server/share')
          WindowsPath('//server/share')

     Several variant forms are supported:

          >>> p = Path.from_uri('file:////server/share')
          WindowsPath('//server/share')
          >>> p = Path.from_uri('file://///server/share')
          WindowsPath('//server/share')
          >>> p = Path.from_uri('file:c:/windows')
          WindowsPath('c:/windows')
          >>> p = Path.from_uri('file:/c|/windows')
          WindowsPath('c:/windows')

     *note ValueError: 202. is raised if the URI does not start with
     ‘file:’, or the parsed path isn’t absolute.

     Added in version 3.13.

 -- Method: Path.as_uri ()

     Represent the path as a ‘file’ URI. *note ValueError: 202. is
     raised if the path isn’t absolute.

          >>> p = PosixPath('/etc/passwd')
          >>> p.as_uri()
          'file:///etc/passwd'
          >>> p = WindowsPath('c:/Windows')
          >>> p.as_uri()
          'file:///c:/Windows'

     For historical reasons, this method is also available from *note
     PurePath: 4a9. objects.  However, its use of *note os.fsencode():
     c76. makes it strictly impure.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc8089.html


File: python.info,  Node: Expanding and resolving paths,  Next: Querying file type and status,  Prev: Parsing and generating URIs,  Up: Concrete paths

5.11.1.10 Expanding and resolving paths
.......................................

 -- Method: classmethod Path.home ()

     Return a new path object representing the user’s home directory (as
     returned by *note os.path.expanduser(): a21. with ‘~’ construct).
     If the home directory can’t be resolved, *note RuntimeError: 195.
     is raised.

          >>> Path.home()
          PosixPath('/home/antoine')

     Added in version 3.5.

 -- Method: Path.expanduser ()

     Return a new path with expanded ‘~’ and ‘~user’ constructs, as
     returned by *note os.path.expanduser(): a21.  If a home directory
     can’t be resolved, *note RuntimeError: 195. is raised.

          >>> p = PosixPath('~/films/Monty Python')
          >>> p.expanduser()
          PosixPath('/home/eric/films/Monty Python')

     Added in version 3.5.

 -- Method: classmethod Path.cwd ()

     Return a new path object representing the current directory (as
     returned by *note os.getcwd(): 16a1.):

          >>> Path.cwd()
          PosixPath('/home/antoine/pathlib')

 -- Method: Path.absolute ()

     Make the path absolute, without normalization or resolving
     symlinks.  Returns a new path object:

          >>> p = Path('tests')
          >>> p
          PosixPath('tests')
          >>> p.absolute()
          PosixPath('/home/antoine/pathlib/tests')

 -- Method: Path.resolve (strict=False)

     Make the path absolute, resolving any symlinks.  A new path object
     is returned:

          >>> p = Path()
          >>> p
          PosixPath('.')
          >>> p.resolve()
          PosixPath('/home/antoine/pathlib')

     “‘..’” components are also eliminated (this is the only method to
     do so):

          >>> p = Path('docs/../setup.py')
          >>> p.resolve()
          PosixPath('/home/antoine/pathlib/setup.py')

     If a path doesn’t exist or a symlink loop is encountered, and
     'strict' is ‘True’, *note OSError: 41a. is raised.  If 'strict' is
     ‘False’, the path is resolved as far as possible and any remainder
     is appended without checking whether it exists.

     Changed in version 3.6: The 'strict' parameter was added (pre-3.6
     behavior is strict).

     Changed in version 3.13: Symlink loops are treated like other
     errors: *note OSError: 41a. is raised in strict mode, and no
     exception is raised in non-strict mode.  In previous versions,
     *note RuntimeError: 195. is raised no matter the value of 'strict'.

 -- Method: Path.readlink ()

     Return the path to which the symbolic link points (as returned by
     *note os.readlink(): 929.):

          >>> p = Path('mylink')
          >>> p.symlink_to('setup.py')
          >>> p.readlink()
          PosixPath('setup.py')

     Added in version 3.9.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. if
     *note os.readlink(): 929. is not available.  In previous versions,
     *note NotImplementedError: 228. was raised.


File: python.info,  Node: Querying file type and status,  Next: Reading and writing files,  Prev: Expanding and resolving paths,  Up: Concrete paths

5.11.1.11 Querying file type and status
.......................................

Changed in version 3.8: *note exists(): a23, *note is_dir(): 230, *note
is_file(): 22f, *note is_mount(): a24, *note is_symlink(): a25, *note
is_block_device(): a26, *note is_char_device(): a27, *note is_fifo():
a28, *note is_socket(): a29. now return ‘False’ instead of raising an
exception for paths that contain characters unrepresentable at the OS
level.

 -- Method: Path.stat (*, follow_symlinks=True)

     Return an *note os.stat_result: 1510. object containing information
     about this path, like *note os.stat(): 4a3.  The result is looked
     up at each call to this method.

     This method normally follows symlinks; to stat a symlink add the
     argument ‘follow_symlinks=False’, or use *note lstat(): 2990.

          >>> p = Path('setup.py')
          >>> p.stat().st_size
          956
          >>> p.stat().st_mtime
          1327883547.852554

     Changed in version 3.10: The 'follow_symlinks' parameter was added.

 -- Method: Path.lstat ()

     Like *note Path.stat(): 829. but, if the path points to a symbolic
     link, return the symbolic link’s information rather than its
     target’s.

 -- Method: Path.exists (*, follow_symlinks=True)

     Return ‘True’ if the path points to an existing file or directory.

     This method normally follows symlinks; to check if a symlink
     exists, add the argument ‘follow_symlinks=False’.

          >>> Path('.').exists()
          True
          >>> Path('setup.py').exists()
          True
          >>> Path('/etc').exists()
          True
          >>> Path('nonexistentfile').exists()
          False

     Changed in version 3.12: The 'follow_symlinks' parameter was added.

 -- Method: Path.is_file (*, follow_symlinks=True)

     Return ‘True’ if the path points to a regular file, ‘False’ if it
     points to another kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

     This method normally follows symlinks; to exclude symlinks, add the
     argument ‘follow_symlinks=False’.

     Changed in version 3.13: The 'follow_symlinks' parameter was added.

 -- Method: Path.is_dir (*, follow_symlinks=True)

     Return ‘True’ if the path points to a directory, ‘False’ if it
     points to another kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

     This method normally follows symlinks; to exclude symlinks to
     directories, add the argument ‘follow_symlinks=False’.

     Changed in version 3.13: The 'follow_symlinks' parameter was added.

 -- Method: Path.is_symlink ()

     Return ‘True’ if the path points to a symbolic link, ‘False’
     otherwise.

     ‘False’ is also returned if the path doesn’t exist; other errors
     (such as permission errors) are propagated.

 -- Method: Path.is_junction ()

     Return ‘True’ if the path points to a junction, and ‘False’ for any
     other type of file.  Currently only Windows supports junctions.

     Added in version 3.12.

 -- Method: Path.is_mount ()

     Return ‘True’ if the path is a 'mount point': a point in a file
     system where a different file system has been mounted.  On POSIX,
     the function checks whether 'path'’s parent, ‘path/..’, is on a
     different device than 'path', or whether ‘path/..’ and 'path' point
     to the same i-node on the same device — this should detect mount
     points for all Unix and POSIX variants.  On Windows, a mount point
     is considered to be a drive letter root (e.g.  ‘c:\’), a UNC share
     (e.g.  ‘\\server\share’), or a mounted filesystem directory.

     Added in version 3.7.

     Changed in version 3.12: Windows support was added.

 -- Method: Path.is_socket ()

     Return ‘True’ if the path points to a Unix socket (or a symbolic
     link pointing to a Unix socket), ‘False’ if it points to another
     kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

 -- Method: Path.is_fifo ()

     Return ‘True’ if the path points to a FIFO (or a symbolic link
     pointing to a FIFO), ‘False’ if it points to another kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

 -- Method: Path.is_block_device ()

     Return ‘True’ if the path points to a block device (or a symbolic
     link pointing to a block device), ‘False’ if it points to another
     kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

 -- Method: Path.is_char_device ()

     Return ‘True’ if the path points to a character device (or a
     symbolic link pointing to a character device), ‘False’ if it points
     to another kind of file.

     ‘False’ is also returned if the path doesn’t exist or is a broken
     symlink; other errors (such as permission errors) are propagated.

 -- Method: Path.samefile (other_path)

     Return whether this path points to the same file as 'other_path',
     which can be either a Path object, or a string.  The semantics are
     similar to *note os.path.samefile(): faa. and *note
     os.path.samestat(): fa9.

     An *note OSError: 41a. can be raised if either file cannot be
     accessed for some reason.

          >>> p = Path('spam')
          >>> q = Path('eggs')
          >>> p.samefile(q)
          False
          >>> p.samefile('spam')
          True

     Added in version 3.5.


File: python.info,  Node: Reading and writing files,  Next: Reading directories,  Prev: Querying file type and status,  Up: Concrete paths

5.11.1.12 Reading and writing files
...................................

 -- Method: Path.open (mode='r', buffering=-1, encoding=None,
          errors=None, newline=None)

     Open the file pointed to by the path, like the built-in *note
     open(): 51f. function does:

          >>> p = Path('setup.py')
          >>> with p.open() as f:
          ...     f.readline()
          ...
          '#!/usr/bin/env python3\n'

 -- Method: Path.read_text (encoding=None, errors=None, newline=None)

     Return the decoded contents of the pointed-to file as a string:

          >>> p = Path('my_text_file')
          >>> p.write_text('Text file contents')
          18
          >>> p.read_text()
          'Text file contents'

     The file is opened and then closed.  The optional parameters have
     the same meaning as in *note open(): 51f.

     Added in version 3.5.

     Changed in version 3.13: The 'newline' parameter was added.

 -- Method: Path.read_bytes ()

     Return the binary contents of the pointed-to file as a bytes
     object:

          >>> p = Path('my_binary_file')
          >>> p.write_bytes(b'Binary file contents')
          20
          >>> p.read_bytes()
          b'Binary file contents'

     Added in version 3.5.

 -- Method: Path.write_text (data, encoding=None, errors=None,
          newline=None)

     Open the file pointed to in text mode, write 'data' to it, and
     close the file:

          >>> p = Path('my_text_file')
          >>> p.write_text('Text file contents')
          18
          >>> p.read_text()
          'Text file contents'

     An existing file of the same name is overwritten.  The optional
     parameters have the same meaning as in *note open(): 51f.

     Added in version 3.5.

     Changed in version 3.10: The 'newline' parameter was added.

 -- Method: Path.write_bytes (data)

     Open the file pointed to in bytes mode, write 'data' to it, and
     close the file:

          >>> p = Path('my_binary_file')
          >>> p.write_bytes(b'Binary file contents')
          20
          >>> p.read_bytes()
          b'Binary file contents'

     An existing file of the same name is overwritten.

     Added in version 3.5.


File: python.info,  Node: Reading directories,  Next: Creating files and directories,  Prev: Reading and writing files,  Up: Concrete paths

5.11.1.13 Reading directories
.............................

 -- Method: Path.iterdir ()

     When the path points to a directory, yield path objects of the
     directory contents:

          >>> p = Path('docs')
          >>> for child in p.iterdir(): child
          ...
          PosixPath('docs/conf.py')
          PosixPath('docs/_templates')
          PosixPath('docs/make.bat')
          PosixPath('docs/index.rst')
          PosixPath('docs/_build')
          PosixPath('docs/_static')
          PosixPath('docs/Makefile')

     The children are yielded in arbitrary order, and the special
     entries ‘'.'’ and ‘'..'’ are not included.  If a file is removed
     from or added to the directory after creating the iterator, it is
     unspecified whether a path object for that file is included.

     If the path is not a directory or otherwise inaccessible, *note
     OSError: 41a. is raised.

 -- Method: Path.glob (pattern, *, case_sensitive=None,
          recurse_symlinks=False)

     Glob the given relative 'pattern' in the directory represented by
     this path, yielding all matching files (of any kind):

          >>> sorted(Path('.').glob('*.py'))
          [PosixPath('pathlib.py'), PosixPath('setup.py'), PosixPath('test_pathlib.py')]
          >>> sorted(Path('.').glob('*/*.py'))
          [PosixPath('docs/conf.py')]
          >>> sorted(Path('.').glob('**/*.py'))
          [PosixPath('build/lib/pathlib.py'),
           PosixPath('docs/conf.py'),
           PosixPath('pathlib.py'),
           PosixPath('setup.py'),
           PosixPath('test_pathlib.py')]

          Note: The paths are returned in no particular order.  If you
          need a specific order, sort the results.

     See also
     ........

     *note Pattern language: 2988. documentation.

     By default, or when the 'case_sensitive' keyword-only argument is
     set to ‘None’, this method matches paths using platform-specific
     casing rules: typically, case-sensitive on POSIX, and
     case-insensitive on Windows.  Set 'case_sensitive' to ‘True’ or
     ‘False’ to override this behaviour.

     By default, or when the 'recurse_symlinks' keyword-only argument is
     set to ‘False’, this method follows symlinks except when expanding
     “‘**’” wildcards.  Set 'recurse_symlinks' to ‘True’ to always
     follow symlinks.

     Raises an *note auditing event: 1a15. ‘pathlib.Path.glob’ with
     arguments ‘self’, ‘pattern’.

     Changed in version 3.12: The 'case_sensitive' parameter was added.

     Changed in version 3.13: The 'recurse_symlinks' parameter was
     added.

     Changed in version 3.13: The 'pattern' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.13: Any *note OSError: 41a. exceptions raised
     from scanning the filesystem are suppressed.  In previous versions,
     such exceptions are suppressed in many cases, but not all.

 -- Method: Path.rglob (pattern, *, case_sensitive=None,
          recurse_symlinks=False)

     Glob the given relative 'pattern' recursively.  This is like
     calling *note Path.glob(): 22d. with “‘**/’” added in front of the
     'pattern'.

          Note: The paths are returned in no particular order.  If you
          need a specific order, sort the results.

     See also
     ........

     *note Pattern language: 2988. and *note Path.glob(): 22d.
     documentation.

     Raises an *note auditing event: 1a15. ‘pathlib.Path.rglob’ with
     arguments ‘self’, ‘pattern’.

     Changed in version 3.12: The 'case_sensitive' parameter was added.

     Changed in version 3.13: The 'recurse_symlinks' parameter was
     added.

     Changed in version 3.13: The 'pattern' parameter accepts a *note
     path-like object: 2a0.

 -- Method: Path.walk (top_down=True, on_error=None,
          follow_symlinks=False)

     Generate the file names in a directory tree by walking the tree
     either top-down or bottom-up.

     For each directory in the directory tree rooted at 'self'
     (including 'self' but excluding ‘.’ and ‘..’), the method yields a
     3-tuple of ‘(dirpath, dirnames, filenames)’.

     'dirpath' is a *note Path: 229. to the directory currently being
     walked, 'dirnames' is a list of strings for the names of
     subdirectories in 'dirpath' (excluding ‘'.'’ and ‘'..'’), and
     'filenames' is a list of strings for the names of the non-directory
     files in 'dirpath'.  To get a full path (which begins with 'self')
     to a file or directory in 'dirpath', do ‘dirpath / name’.  Whether
     or not the lists are sorted is file system-dependent.

     If the optional argument 'top_down' is true (which is the default),
     the triple for a directory is generated before the triples for any
     of its subdirectories (directories are walked top-down).  If
     'top_down' is false, the triple for a directory is generated after
     the triples for all of its subdirectories (directories are walked
     bottom-up).  No matter the value of 'top_down', the list of
     subdirectories is retrieved before the triples for the directory
     and its subdirectories are walked.

     When 'top_down' is true, the caller can modify the 'dirnames' list
     in-place (for example, using *note del: 18c2. or slice assignment),
     and ‘Path.walk()’ will only recurse into the subdirectories whose
     names remain in 'dirnames'.  This can be used to prune the search,
     or to impose a specific order of visiting, or even to inform
     ‘Path.walk()’ about directories the caller creates or renames
     before it resumes ‘Path.walk()’ again.  Modifying 'dirnames' when
     'top_down' is false has no effect on the behavior of ‘Path.walk()’
     since the directories in 'dirnames' have already been generated by
     the time 'dirnames' is yielded to the caller.

     By default, errors from *note os.scandir(): a6d. are ignored.  If
     the optional argument 'on_error' is specified, it should be a
     callable; it will be called with one argument, an *note OSError:
     41a. instance.  The callable can handle the error to continue the
     walk or re-raise it to stop the walk.  Note that the filename is
     available as the ‘filename’ attribute of the exception object.

     By default, ‘Path.walk()’ does not follow symbolic links, and
     instead adds them to the 'filenames' list.  Set 'follow_symlinks'
     to true to resolve symlinks and place them in 'dirnames' and
     'filenames' as appropriate for their targets, and consequently
     visit directories pointed to by symlinks (where supported).

          Note: Be aware that setting 'follow_symlinks' to true can lead
          to infinite recursion if a link points to a parent directory
          of itself.  ‘Path.walk()’ does not keep track of the
          directories it has already visited.

          Note: ‘Path.walk()’ assumes the directories it walks are not
          modified during execution.  For example, if a directory from
          'dirnames' has been replaced with a symlink and
          'follow_symlinks' is false, ‘Path.walk()’ will still try to
          descend into it.  To prevent such behavior, remove directories
          from 'dirnames' as appropriate.

          Note: Unlike *note os.walk(): 4ac, ‘Path.walk()’ lists
          symlinks to directories in 'filenames' if 'follow_symlinks' is
          false.

     This example displays the number of bytes used by all files in each
     directory, while ignoring ‘__pycache__’ directories:

          from pathlib import Path
          for root, dirs, files in Path("cpython/Lib/concurrent").walk(on_error=print):
            print(
                root,
                "consumes",
                sum((root / file).stat().st_size for file in files),
                "bytes in",
                len(files),
                "non-directory files"
            )
            if '__pycache__' in dirs:
                  dirs.remove('__pycache__')

     This next example is a simple implementation of *note
     shutil.rmtree(): 301.  Walking the tree bottom-up is essential as
     *note rmdir(): 2994. doesn’t allow deleting a directory before it
     is empty:

          # Delete everything reachable from the directory "top".
          # CAUTION:  This is dangerous! For example, if top == Path('/'),
          # it could delete all of your files.
          for root, dirs, files in top.walk(top_down=False):
              for name in files:
                  (root / name).unlink()
              for name in dirs:
                  (root / name).rmdir()

     Added in version 3.12.


File: python.info,  Node: Creating files and directories,  Next: Renaming and deleting,  Prev: Reading directories,  Up: Concrete paths

5.11.1.14 Creating files and directories
........................................

 -- Method: Path.touch (mode=0o666, exist_ok=True)

     Create a file at this given path.  If 'mode' is given, it is
     combined with the process’s ‘umask’ value to determine the file
     mode and access flags.  If the file already exists, the function
     succeeds when 'exist_ok' is true (and its modification time is
     updated to the current time), otherwise *note FileExistsError:
     105b. is raised.

     See also
     ........

     The *note open(): 2992, *note write_text(): e77. and *note
     write_bytes(): e79. methods are often used to create files.

 -- Method: Path.mkdir (mode=0o777, parents=False, exist_ok=False)

     Create a new directory at this given path.  If 'mode' is given, it
     is combined with the process’s ‘umask’ value to determine the file
     mode and access flags.  If the path already exists, *note
     FileExistsError: 105b. is raised.

     If 'parents' is true, any missing parents of this path are created
     as needed; they are created with the default permissions without
     taking 'mode' into account (mimicking the POSIX ‘mkdir -p’
     command).

     If 'parents' is false (the default), a missing parent raises *note
     FileNotFoundError: 42e.

     If 'exist_ok' is false (the default), *note FileExistsError: 105b.
     is raised if the target directory already exists.

     If 'exist_ok' is true, *note FileExistsError: 105b. will not be
     raised unless the given path already exists in the file system and
     is not a directory (same behavior as the POSIX ‘mkdir -p’ command).

     Changed in version 3.5: The 'exist_ok' parameter was added.

 -- Method: Path.symlink_to (target, target_is_directory=False)

     Make this path a symbolic link pointing to 'target'.

     On Windows, a symlink represents either a file or a directory, and
     does not morph to the target dynamically.  If the target is
     present, the type of the symlink will be created to match.
     Otherwise, the symlink will be created as a directory if
     'target_is_directory' is true or a file symlink (the default)
     otherwise.  On non-Windows platforms, 'target_is_directory' is
     ignored.

          >>> p = Path('mylink')
          >>> p.symlink_to('setup.py')
          >>> p.resolve()
          PosixPath('/home/antoine/pathlib/setup.py')
          >>> p.stat().st_size
          956
          >>> p.lstat().st_size
          8

          Note: The order of arguments (link, target) is the reverse of
          *note os.symlink(): 1138.’s.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. if
     *note os.symlink(): 1138. is not available.  In previous versions,
     *note NotImplementedError: 228. was raised.

 -- Method: Path.hardlink_to (target)

     Make this path a hard link to the same file as 'target'.

          Note: The order of arguments (link, target) is the reverse of
          *note os.link(): 1133.’s.

     Added in version 3.10.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. if
     *note os.link(): 1133. is not available.  In previous versions,
     *note NotImplementedError: 228. was raised.


File: python.info,  Node: Renaming and deleting,  Next: Permissions and ownership,  Prev: Creating files and directories,  Up: Concrete paths

5.11.1.15 Renaming and deleting
...............................

 -- Method: Path.rename (target)

     Rename this file or directory to the given 'target', and return a
     new ‘Path’ instance pointing to 'target'.  On Unix, if 'target'
     exists and is a file, it will be replaced silently if the user has
     permission.  On Windows, if 'target' exists, *note FileExistsError:
     105b. will be raised.  'target' can be either a string or another
     path object:

          >>> p = Path('foo')
          >>> p.open('w').write('some text')
          9
          >>> target = Path('bar')
          >>> p.rename(target)
          PosixPath('bar')
          >>> target.open().read()
          'some text'

     The target path may be absolute or relative.  Relative paths are
     interpreted relative to the current working directory, 'not' the
     directory of the ‘Path’ object.

     It is implemented in terms of *note os.rename(): 1135. and gives
     the same guarantees.

     Changed in version 3.8: Added return value, return the new ‘Path’
     instance.

 -- Method: Path.replace (target)

     Rename this file or directory to the given 'target', and return a
     new ‘Path’ instance pointing to 'target'.  If 'target' points to an
     existing file or empty directory, it will be unconditionally
     replaced.

     The target path may be absolute or relative.  Relative paths are
     interpreted relative to the current working directory, 'not' the
     directory of the ‘Path’ object.

     Changed in version 3.8: Added return value, return the new ‘Path’
     instance.

 -- Method: Path.unlink (missing_ok=False)

     Remove this file or symbolic link.  If the path points to a
     directory, use *note Path.rmdir(): 2994. instead.

     If 'missing_ok' is false (the default), *note FileNotFoundError:
     42e. is raised if the path does not exist.

     If 'missing_ok' is true, *note FileNotFoundError: 42e. exceptions
     will be ignored (same behavior as the POSIX ‘rm -f’ command).

     Changed in version 3.8: The 'missing_ok' parameter was added.

 -- Method: Path.rmdir ()

     Remove this directory.  The directory must be empty.


File: python.info,  Node: Permissions and ownership,  Prev: Renaming and deleting,  Up: Concrete paths

5.11.1.16 Permissions and ownership
...................................

 -- Method: Path.owner (*, follow_symlinks=True)

     Return the name of the user owning the file.  *note KeyError: 345.
     is raised if the file’s user identifier (UID) isn’t found in the
     system database.

     This method normally follows symlinks; to get the owner of the
     symlink, add the argument ‘follow_symlinks=False’.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. if
     the *note pwd: b2. module is not available.  In earlier versions,
     *note NotImplementedError: 228. was raised.

     Changed in version 3.13: The 'follow_symlinks' parameter was added.

 -- Method: Path.group (*, follow_symlinks=True)

     Return the name of the group owning the file.  *note KeyError: 345.
     is raised if the file’s group identifier (GID) isn’t found in the
     system database.

     This method normally follows symlinks; to get the group of the
     symlink, add the argument ‘follow_symlinks=False’.

     Changed in version 3.13: Raises *note UnsupportedOperation: 227. if
     the *note grp: 66. module is not available.  In earlier versions,
     *note NotImplementedError: 228. was raised.

     Changed in version 3.13: The 'follow_symlinks' parameter was added.

 -- Method: Path.chmod (mode, *, follow_symlinks=True)

     Change the file mode and permissions, like *note os.chmod(): 21b.

     This method normally follows symlinks.  Some Unix flavours support
     changing permissions on the symlink itself; on these platforms you
     may add the argument ‘follow_symlinks=False’, or use *note
     lchmod(): 299b.

          >>> p = Path('setup.py')
          >>> p.stat().st_mode
          33277
          >>> p.chmod(0o444)
          >>> p.stat().st_mode
          33060

     Changed in version 3.10: The 'follow_symlinks' parameter was added.

 -- Method: Path.lchmod (mode)

     Like *note Path.chmod(): 82a. but, if the path points to a symbolic
     link, the symbolic link’s mode is changed rather than its target’s.


File: python.info,  Node: Pattern language,  Next: Comparison to the glob module,  Prev: Concrete paths,  Up: pathlib — Object-oriented filesystem paths

5.11.1.17 Pattern language
..........................

The following wildcards are supported in patterns for *note
full_match(): 22b, *note glob(): 22d. and *note rglob(): 22e.:

‘**’ (entire segment)

     Matches any number of file or directory segments, including zero.

‘*’ (entire segment)

     Matches one file or directory segment.

‘*’ (part of a segment)

     Matches any number of non-separator characters, including zero.

‘?’

     Matches one non-separator character.

‘[seq]’

     Matches one character in 'seq', where 'seq' is a sequence of
     characters.  Range expressions are supported; for example, ‘[a-z]’
     matches any lowercase ASCII letter.  Multiple ranges can be
     combined: ‘[a-zA-Z0-9_]’ matches any ASCII letter, digit, or
     underscore.

‘[!seq]’

     Matches one character not in 'seq', where 'seq' follows the same
     rules as above.

For a literal match, wrap the meta-characters in brackets.  For example,
‘"[?]"’ matches the character ‘"?"’.

The “‘**’” wildcard enables recursive globbing.  A few examples:

Pattern                       Meaning
                              
--------------------------------------------------------------------------------------------------------
                              
“‘**/*’”                      Any path with at least one segment.
                              
                              
“‘**/*.py’”                   Any path with a final segment ending “‘.py’”.
                              
                              
“‘assets/**’”                 Any path starting with “‘assets/’”.
                              
                              
“‘assets/**/*’”               Any path starting with “‘assets/’”, excluding “‘assets/’” itself.
                              

     Note: Globbing with the “‘**’” wildcard visits every directory in
     the tree.  Large directory trees may take a long time to search.

Changed in version 3.13: Globbing with a pattern that ends with “‘**’”
returns both files and directories.  In previous versions, only
directories were returned.

In *note Path.glob(): 22d. and *note rglob(): 22e, a trailing slash may
be added to the pattern to match only directories.

Changed in version 3.11: Globbing with a pattern that ends with a
pathname components separator (*note sep: 66d. or *note altsep: 66e.)
returns only directories.


File: python.info,  Node: Comparison to the glob module,  Next: Comparison to the os and os path modules,  Prev: Pattern language,  Up: pathlib — Object-oriented filesystem paths

5.11.1.18 Comparison to the ‘glob’ module
.........................................

The patterns accepted and results generated by *note Path.glob(): 22d.
and *note Path.rglob(): 22e. differ slightly from those by the *note
glob: 64. module:

  1. Files beginning with a dot are not special in pathlib.  This is
     like passing ‘include_hidden=True’ to *note glob.glob(): 29f.

  2. “‘**’” pattern components are always recursive in pathlib.  This is
     like passing ‘recursive=True’ to *note glob.glob(): 29f.

  3. “‘**’” pattern components do not follow symlinks by default in
     pathlib.  This behaviour has no equivalent in *note glob.glob():
     29f, but you can pass ‘recurse_symlinks=True’ to *note Path.glob():
     22d. for compatible behaviour.

  4. Like all *note PurePath: 4a9. and *note Path: 229. objects, the
     values returned from *note Path.glob(): 22d. and *note
     Path.rglob(): 22e. don’t include trailing slashes.

  5. The values returned from pathlib’s ‘path.glob()’ and ‘path.rglob()’
     include the 'path' as a prefix, unlike the results of
     ‘glob.glob(root_dir=path)’.

  6. The values returned from pathlib’s ‘path.glob()’ and ‘path.rglob()’
     may include 'path' itself, for example when globbing “‘**’”,
     whereas the results of ‘glob.glob(root_dir=path)’ never include an
     empty string that would correspond to 'path'.


File: python.info,  Node: Comparison to the os and os path modules,  Prev: Comparison to the glob module,  Up: pathlib — Object-oriented filesystem paths

5.11.1.19 Comparison to the ‘os’ and ‘os.path’ modules
......................................................

pathlib implements path operations using *note PurePath: 4a9. and *note
Path: 229. objects, and so it’s said to be 'object-oriented'.  On the
other hand, the *note os: a1. and *note os.path: a2. modules supply
functions that work with low-level ‘str’ and ‘bytes’ objects, which is a
more 'procedural' approach.  Some users consider the object-oriented
style to be more readable.

Many functions in *note os: a1. and *note os.path: a2. support ‘bytes’
paths and *note paths relative to directory descriptors: 112e.  These
features aren’t available in pathlib.

Python’s ‘str’ and ‘bytes’ types, and portions of the *note os: a1. and
*note os.path: a2. modules, are written in C and are very speedy.
pathlib is written in pure Python and is often slower, but rarely slow
enough to matter.

pathlib’s path normalization is slightly more opinionated and consistent
than *note os.path: a2.  For example, whereas *note os.path.abspath():
1364. eliminates “‘..’” segments from a path, which may change its
meaning if symlinks are involved, *note Path.absolute(): 17bf. preserves
these segments for greater safety.

pathlib’s path normalization may render it unsuitable for some
applications:

  1. pathlib normalizes ‘Path("my_folder/")’ to ‘Path("my_folder")’,
     which changes a path’s meaning when supplied to various operating
     system APIs and command-line utilities.  Specifically, the absence
     of a trailing separator may allow the path to be resolved as either
     a file or directory, rather than a directory only.

  2. pathlib normalizes ‘Path("./my_program")’ to ‘Path("my_program")’,
     which changes a path’s meaning when used as an executable search
     path, such as in a shell or when spawning a child process.
     Specifically, the absence of a separator in the path may force it
     to be looked up in ‘PATH’ rather than the current directory.

As a consequence of these differences, pathlib is not a drop-in
replacement for *note os.path: a2.

* Menu:

* Corresponding tools::


File: python.info,  Node: Corresponding tools,  Up: Comparison to the os and os path modules

5.11.1.20 Corresponding tools
.............................

Below is a table mapping various *note os: a1. functions to their
corresponding *note PurePath: 4a9./*note Path: 229. equivalent.

*note os: a1. and *note os.path: a2.      ‘pathlib’
                                          
---------------------------------------------------------------------------------------------
                                          
*note os.path.dirname(): 29a0.            *note PurePath.parent: 183d.
                                          
                                          
*note os.path.basename(): 29a1.           *note PurePath.name: 2982.
                                          
                                          
*note os.path.splitext(): 29a2.           *note PurePath.stem: 2985,
                                          *note PurePath.suffix: 2983.
                                          
                                          
*note os.path.join(): 173c.               *note PurePath.joinpath(): 2987.
                                          
                                          
*note os.path.isabs(): 224.               *note PurePath.is_absolute(): 183c.
                                          
                                          
*note os.path.relpath(): 4ad.             *note PurePath.relative_to(): 2ca. (1)
                                          
                                          
*note os.path.expanduser(): a21.          *note Path.expanduser(): e75. (2)
                                          
                                          
*note os.path.realpath(): 225.            *note Path.resolve(): 180c.
                                          
                                          
*note os.path.abspath(): 1364.            *note Path.absolute(): 17bf. (3)
                                          
                                          
*note os.path.exists(): a1b.              *note Path.exists(): a23.
                                          
                                          
*note os.path.isfile(): a1e.              *note Path.is_file(): 22f.
                                          
                                          
*note os.path.isdir(): a1d.               *note Path.is_dir(): 230.
                                          
                                          
*note os.path.islink(): a19.              *note Path.is_symlink(): a25.
                                          
                                          
*note os.path.isjunction(): 4a6.          *note Path.is_junction(): 4ae.
                                          
                                          
*note os.path.ismount(): a1f.             *note Path.is_mount(): a24.
                                          
                                          
*note os.path.samefile(): faa.            *note Path.samefile(): e73.
                                          
                                          
*note os.getcwd(): 16a1.                  *note Path.cwd(): 183b.
                                          
                                          
*note os.stat(): 4a3.                     *note Path.stat(): 829.
                                          
                                          
*note os.lstat(): 4a4.                    *note Path.lstat(): 2990.
                                          
                                          
*note os.listdir(): 113e.                 *note Path.iterdir(): 173a.
                                          
                                          
*note os.walk(): 4ac.                     *note Path.walk(): 4ab. (4)
                                          
                                          
*note os.mkdir(): 21d,                    *note Path.mkdir(): e74.
*note os.makedirs(): 21e.                 

*note os.link(): 1133.                    *note Path.hardlink_to(): 827.
                                          
                                          
*note os.symlink(): 1138.                 *note Path.symlink_to(): 828.
                                          
                                          
*note os.readlink(): 929.                 *note Path.readlink(): 928.
                                          
                                          
*note os.rename(): 1135.                  *note Path.rename(): 2998.
                                          
                                          
*note os.replace(): 1136.                 *note Path.replace(): 2999.
                                          
                                          
*note os.remove(): 1134,                  *note Path.unlink(): 1b82.
*note os.unlink(): 1139.                  

*note os.rmdir(): 1137.                   *note Path.rmdir(): 2994.
                                          
                                          
*note os.chmod(): 21b.                    *note Path.chmod(): 82a.
                                          
                                          
*note os.lchmod(): 21a.                   *note Path.lchmod(): 299b.
                                          

   ---------- Footnotes ----------

   (1) *note os.path.relpath(): 4ad. calls *note abspath(): 1364. to
make paths absolute and remove “‘..’” parts, whereas *note
PurePath.relative_to(): 2ca. is a lexical operation that raises *note
ValueError: 202. when its inputs’ anchors differ (e.g.  if one path is
absolute and the other relative.)

   (2) *note os.path.expanduser(): a21. returns the path unchanged if
the home directory can’t be resolved, whereas *note Path.expanduser():
e75. raises *note RuntimeError: 195.

   (3) *note os.path.abspath(): 1364. removes “‘..’” components without
resolving symlinks, which may change the meaning of the path, whereas
*note Path.absolute(): 17bf. leaves any “‘..’” components in the path.

   (4) *note os.walk(): 4ac. always follows symlinks when categorizing
paths into 'dirnames' and 'filenames', whereas *note Path.walk(): 4ab.
categorizes all symlinks into 'filenames' when 'follow_symlinks' is
false (the default.)


File: python.info,  Node: os path — Common pathname manipulations,  Next: stat — Interpreting stat results,  Prev: pathlib — Object-oriented filesystem paths,  Up: File and Directory Access

5.11.2 ‘os.path’ — Common pathname manipulations
------------------------------------------------

'Source code:' Lib/genericpath.py(1), Lib/posixpath.py(2) (for POSIX)
and Lib/ntpath.py(3) (for Windows).

__________________________________________________________________

This module implements some useful functions on pathnames.  To read or
write files see *note open(): 51f, and for accessing the filesystem see
the *note os: a1. module.  The path parameters can be passed as strings,
or bytes, or any object implementing the *note os.PathLike: c72.
protocol.

Unlike a Unix shell, Python does not do any 'automatic' path expansions.
Functions such as *note expanduser(): a21. and *note expandvars(): 1427.
can be invoked explicitly when an application desires shell-like path
expansion.  (See also the *note glob: 64. module.)

See also
........

The *note pathlib: a4. module offers high-level path objects.

     Note: All of these functions accept either only bytes or only
     string objects as their parameters.  The result is an object of the
     same type, if a path or file name is returned.

     Note: Since different operating systems have different path name
     conventions, there are several versions of this module in the
     standard library.  The ‘os.path’ module is always the path module
     suitable for the operating system Python is running on, and
     therefore usable for local paths.  However, you can also import and
     use the individual modules if you want to manipulate a path that is
     'always' in one of the different formats.  They all have the same
     interface:

        * ‘posixpath’ for UNIX-style paths

        * ‘ntpath’ for Windows paths

Changed in version 3.8: *note exists(): a1b, *note lexists(): a1c, *note
isdir(): a1d, *note isfile(): a1e, *note islink(): a19, and *note
ismount(): a1f. now return ‘False’ instead of raising an exception for
paths that contain characters or bytes unrepresentable at the OS level.

 -- Function: os.path.abspath (path)

     Return a normalized absolutized version of the pathname 'path'.  On
     most platforms, this is equivalent to calling
     ‘normpath(join(os.getcwd(), path))’.

     See also
     ........

     *note os.path.join(): 173c. and *note os.path.normpath(): 1363.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.basename (path, /)

     Return the base name of pathname 'path'.  This is the second
     element of the pair returned by passing 'path' to the function
     *note split(): 29a6.  Note that the result of this function is
     different from the Unix ‘basename’ program; where ‘basename’ for
     ‘'/foo/bar/'’ returns ‘'bar'’, the ‘basename()’ function returns an
     empty string (‘''’).

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.commonpath (paths)

     Return the longest common sub-path of each pathname in the iterable
     'paths'.  Raise *note ValueError: 202. if 'paths' contain both
     absolute and relative pathnames, if 'paths' are on different
     drives, or if 'paths' is empty.  Unlike *note commonprefix(): e71,
     this returns a valid path.

     Added in version 3.5.

     Changed in version 3.6: Accepts a sequence of *note path-like
     objects: 2a0.

     Changed in version 3.13: Any iterable can now be passed, rather
     than just sequences.

 -- Function: os.path.commonprefix (list, /)

     Return the longest string prefix (taken character-by-character)
     that is a prefix of all strings in 'list'.  If 'list' is empty,
     return the empty string (‘''’).

          Warning: This function may return invalid paths because it
          works a character at a time.  If you need a 'common path
          prefix', then the algorithm implemented in this function is
          not secure.  Use *note commonpath(): e70. for finding a common
          path prefix.

               >>> os.path.commonprefix(['/usr/lib', '/usr/local/lib'])
               '/usr/l'

               >>> os.path.commonpath(['/usr/lib', '/usr/local/lib'])
               '/usr'

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.dirname (path, /)

     Return the directory name of pathname 'path'.  This is the first
     element of the pair returned by passing 'path' to the function
     *note split(): 29a6.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.exists (path)

     Return ‘True’ if 'path' refers to an existing path or an open file
     descriptor.  Returns ‘False’ for broken symbolic links.  On some
     platforms, this function may return ‘False’ if permission is not
     granted to execute *note os.stat(): 4a3. on the requested file,
     even if the 'path' physically exists.

     Changed in version 3.3: 'path' can now be an integer: ‘True’ is
     returned if it is an open file descriptor, ‘False’ otherwise.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.lexists (path)

     Return ‘True’ if 'path' refers to an existing path, including
     broken symbolic links.  Equivalent to *note exists(): a1b. on
     platforms lacking *note os.lstat(): 4a4.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.expanduser (path)

     On Unix and Windows, return the argument with an initial component
     of ‘~’ or ‘~user’ replaced by that 'user'’s home directory.

     On Unix, an initial ‘~’ is replaced by the environment variable
     ‘HOME’ if it is set; otherwise the current user’s home directory is
     looked up in the password directory through the built-in module
     *note pwd: b2.  An initial ‘~user’ is looked up directly in the
     password directory.

     On Windows, ‘USERPROFILE’ will be used if set, otherwise a
     combination of ‘HOMEPATH’ and ‘HOMEDRIVE’ will be used.  An initial
     ‘~user’ is handled by checking that the last directory component of
     the current user’s home directory matches ‘USERNAME’, and replacing
     it if so.

     If the expansion fails or if the path does not begin with a tilde,
     the path is returned unchanged.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.8: No longer uses ‘HOME’ on Windows.

 -- Function: os.path.expandvars (path)

     Return the argument with environment variables expanded.
     Substrings of the form ‘$name’ or ‘${name}’ are replaced by the
     value of environment variable 'name'.  Malformed variable names and
     references to non-existing variables are left unchanged.

     On Windows, ‘%name%’ expansions are supported in addition to
     ‘$name’ and ‘${name}’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.getatime (path, /)

     Return the time of last access of 'path'.  The return value is a
     floating-point number giving the number of seconds since the epoch
     (see the *note time: ee. module).  Raise *note OSError: 41a. if the
     file does not exist or is inaccessible.

 -- Function: os.path.getmtime (path, /)

     Return the time of last modification of 'path'.  The return value
     is a floating-point number giving the number of seconds since the
     epoch (see the *note time: ee. module).  Raise *note OSError: 41a.
     if the file does not exist or is inaccessible.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.getctime (path, /)

     Return the system’s ctime which, on some systems (like Unix) is the
     time of the last metadata change, and, on others (like Windows), is
     the creation time for 'path'.  The return value is a number giving
     the number of seconds since the epoch (see the *note time: ee.
     module).  Raise *note OSError: 41a. if the file does not exist or
     is inaccessible.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.getsize (path, /)

     Return the size, in bytes, of 'path'.  Raise *note OSError: 41a. if
     the file does not exist or is inaccessible.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.isabs (path, /)

     Return ‘True’ if 'path' is an absolute pathname.  On Unix, that
     means it begins with a slash, on Windows that it begins with two
     (back)slashes, or a drive letter, colon, and (back)slash together.

     See also
     ........

     *note abspath(): 1364.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.13: On Windows, returns ‘False’ if the given
     path starts with exactly one (back)slash.

 -- Function: os.path.isfile (path)

     Return ‘True’ if 'path' is an *note existing: a1b. regular file.
     This follows symbolic links, so both *note islink(): a19. and
     ‘isfile()’ can be true for the same path.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.isdir (path, /)

     Return ‘True’ if 'path' is an *note existing: a1b. directory.  This
     follows symbolic links, so both *note islink(): a19. and ‘isdir()’
     can be true for the same path.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.isjunction (path)

     Return ‘True’ if 'path' refers to an *note existing: a1c. directory
     entry that is a junction.  Always return ‘False’ if junctions are
     not supported on the current platform.

     Added in version 3.12.

 -- Function: os.path.islink (path)

     Return ‘True’ if 'path' refers to an *note existing: a1b. directory
     entry that is a symbolic link.  Always ‘False’ if symbolic links
     are not supported by the Python runtime.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.ismount (path)

     Return ‘True’ if pathname 'path' is a 'mount point': a point in a
     file system where a different file system has been mounted.  On
     POSIX, the function checks whether 'path'’s parent, ‘`path'/..’, is
     on a different device than 'path', or whether ‘`path'/..’ and
     'path' point to the same i-node on the same device — this should
     detect mount points for all Unix and POSIX variants.  It is not
     able to reliably detect bind mounts on the same filesystem.  On
     Linux systems, it will always return ‘True’ for btrfs subvolumes,
     even if they aren’t mount points.  On Windows, a drive letter root
     and a share UNC are always mount points, and for any other path
     ‘GetVolumePathName’ is called to see if it is different from the
     input path.

     Changed in version 3.4: Added support for detecting non-root mount
     points on Windows.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.isdevdrive (path)

     Return ‘True’ if pathname 'path' is located on a Windows Dev Drive.
     A Dev Drive is optimized for developer scenarios, and offers faster
     performance for reading and writing files.  It is recommended for
     use for source code, temporary build directories, package caches,
     and other IO-intensive operations.

     May raise an error for an invalid path, for example, one without a
     recognizable drive, but returns ‘False’ on platforms that do not
     support Dev Drives.  See the Windows documentation(4) for
     information on enabling and creating Dev Drives.

     Added in version 3.12.

     Changed in version 3.13: The function is now available on all
     platforms, and will always return ‘False’ on those that have no
     support for Dev Drives

 -- Function: os.path.isreserved (path)

     Return ‘True’ if 'path' is a reserved pathname on the current
     system.

     On Windows, reserved filenames include those that end with a space
     or dot; those that contain colons (i.e.  file streams such as
     “name:stream”), wildcard characters (i.e.  ‘'*?"<>'’), pipe, or
     ASCII control characters; as well as DOS device names such as
     “NUL”, “CON”, “CONIN$”, “CONOUT$”, “AUX”, “PRN”, “COM1”, and
     “LPT1”.

          Note: This function approximates rules for reserved paths on
          most Windows systems.  These rules change over time in various
          Windows releases.  This function may be updated in future
          Python releases as changes to the rules become broadly
          available.

     *note Availability: 1ef7.: Windows.

     Added in version 3.13.

 -- Function: os.path.join (path, /, *paths)

     Join one or more path segments intelligently.  The return value is
     the concatenation of 'path' and all members of '*paths', with
     exactly one directory separator following each non-empty part,
     except the last.  That is, the result will only end in a separator
     if the last part is either empty or ends in a separator.

     If a segment is an absolute path (which on Windows requires both a
     drive and a root), then all previous segments are ignored and
     joining continues from the absolute path segment.  On Linux, for
     example:

          >>> os.path.join('/home/foo', 'bar')
          '/home/foo/bar'
          >>> os.path.join('/home/foo', '/home/bar')
          '/home/bar'

     On Windows, the drive is not reset when a rooted path segment
     (e.g., ‘r'\foo'’) is encountered.  If a segment is on a different
     drive or is an absolute path, all previous segments are ignored and
     the drive is reset.  For example:

          >>> os.path.join('c:\\', 'foo')
          'c:\\foo'
          >>> os.path.join('c:\\foo', 'd:\\bar')
          'd:\\bar'

     Note that since there is a current directory for each drive,
     ‘os.path.join("c:", "foo")’ represents a path relative to the
     current directory on drive ‘C:’ (‘c:foo’), not ‘c:\foo’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'path' and 'paths'.

 -- Function: os.path.normcase (path, /)

     Normalize the case of a pathname.  On Windows, convert all
     characters in the pathname to lowercase, and also convert forward
     slashes to backward slashes.  On other operating systems, return
     the path unchanged.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.normpath (path)

     Normalize a pathname by collapsing redundant separators and
     up-level references so that ‘A//B’, ‘A/B/’, ‘A/./B’ and
     ‘A/foo/../B’ all become ‘A/B’.  This string manipulation may change
     the meaning of a path that contains symbolic links.  On Windows, it
     converts forward slashes to backward slashes.  To normalize case,
     use *note normcase(): 29ab.

          Note: On POSIX systems, in accordance with IEEE Std 1003.1
          2013 Edition; 4.13 Pathname Resolution(5), if a pathname
          begins with exactly two slashes, the first component following
          the leading characters may be interpreted in an
          implementation-defined manner, although more than two leading
          characters shall be treated as a single character.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.realpath (path, /, *, strict=False)

     Return the canonical path of the specified filename, eliminating
     any symbolic links encountered in the path (if they are supported
     by the operating system).  On Windows, this function will also
     resolve MS-DOS (also called 8.3) style names such as ‘C:\\PROGRA~1’
     to ‘C:\\Program Files’.

     By default, the path is evaluated up to the first component that
     does not exist, is a symlink loop, or whose evaluation raises *note
     OSError: 41a.  All such components are appended unchanged to the
     existing part of the path.

     Some errors that are handled this way include “access denied”, “not
     a directory”, or “bad argument to internal function”.  Thus, the
     resulting path may be missing or inaccessible, may still contain
     links or loops, and may traverse non-directories.

     This behavior can be modified by keyword arguments:

     If 'strict' is ‘True’, the first error encountered when evaluating
     the path is re-raised.  In particular, *note FileNotFoundError:
     42e. is raised if 'path' does not exist, or another *note OSError:
     41a. if it is otherwise inaccessible.

     If 'strict' is *note os.path.ALLOW_MISSING: 42d, errors other than
     *note FileNotFoundError: 42e. are re-raised (as with
     ‘strict=True’).  Thus, the returned path will not contain any
     symbolic links, but the named file and some of its parent
     directories may be missing.

          Note: This function emulates the operating system’s procedure
          for making a path canonical, which differs slightly between
          Windows and UNIX with respect to how links and subsequent path
          components interact.

          Operating system APIs make paths canonical as needed, so it’s
          not normally necessary to call this function.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.8: Symbolic links and junctions are now
     resolved on Windows.

     Changed in version 3.10: The 'strict' parameter was added.

     Changed in version 3.13.4: The *note ALLOW_MISSING: 42d. value for
     the 'strict' parameter was added.

 -- Data: os.path.ALLOW_MISSING

     Special value used for the 'strict' argument in *note realpath():
     225.

     Added in version 3.13.4.

 -- Function: os.path.relpath (path, start=os.curdir)

     Return a relative filepath to 'path' either from the current
     directory or from an optional 'start' directory.  This is a path
     computation: the filesystem is not accessed to confirm the
     existence or nature of 'path' or 'start'.  On Windows, *note
     ValueError: 202. is raised when 'path' and 'start' are on different
     drives.

     'start' defaults to *note os.curdir: 29ac.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.samefile (path1, path2, /)

     Return ‘True’ if both pathname arguments refer to the same file or
     directory.  This is determined by the device number and i-node
     number and raises an exception if an *note os.stat(): 4a3. call on
     either pathname fails.

     Changed in version 3.2: Added Windows support.

     Changed in version 3.4: Windows now uses the same implementation as
     all other platforms.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.sameopenfile (fp1, fp2)

     Return ‘True’ if the file descriptors 'fp1' and 'fp2' refer to the
     same file.

     Changed in version 3.2: Added Windows support.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.samestat (stat1, stat2, /)

     Return ‘True’ if the stat tuples 'stat1' and 'stat2' refer to the
     same file.  These structures may have been returned by *note
     os.fstat(): dba, *note os.lstat(): 4a4, or *note os.stat(): 4a3.
     This function implements the underlying comparison used by *note
     samefile(): faa. and *note sameopenfile(): 29ad.

     Changed in version 3.4: Added Windows support.

 -- Function: os.path.split (path, /)

     Split the pathname 'path' into a pair, ‘(head, tail)’ where 'tail'
     is the last pathname component and 'head' is everything leading up
     to that.  The 'tail' part will never contain a slash; if 'path'
     ends in a slash, 'tail' will be empty.  If there is no slash in
     'path', 'head' will be empty.  If 'path' is empty, both 'head' and
     'tail' are empty.  Trailing slashes are stripped from 'head' unless
     it is the root (one or more slashes only).  In all cases,
     ‘join(head, tail)’ returns a path to the same location as 'path'
     (but the strings may differ).  Also see the functions *note join():
     173c, *note dirname(): 29a0. and *note basename(): 29a1.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.splitdrive (path, /)

     Split the pathname 'path' into a pair ‘(drive, tail)’ where 'drive'
     is either a mount point or the empty string.  On systems which do
     not use drive specifications, 'drive' will always be the empty
     string.  In all cases, ‘drive + tail’ will be the same as 'path'.

     On Windows, splits a pathname into drive/UNC sharepoint and
     relative path.

     If the path contains a drive letter, drive will contain everything
     up to and including the colon:

          >>> splitdrive("c:/dir")
          ("c:", "/dir")

     If the path contains a UNC path, drive will contain the host name
     and share:

          >>> splitdrive("//host/computer/dir")
          ("//host/computer", "/dir")

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.path.splitroot (path, /)

     Split the pathname 'path' into a 3-item tuple ‘(drive, root, tail)’
     where 'drive' is a device name or mount point, 'root' is a string
     of separators after the drive, and 'tail' is everything after the
     root.  Any of these items may be the empty string.  In all cases,
     ‘drive + root + tail’ will be the same as 'path'.

     On POSIX systems, 'drive' is always empty.  The 'root' may be empty
     (if 'path' is relative), a single forward slash (if 'path' is
     absolute), or two forward slashes (implementation-defined per IEEE
     Std 1003.1-2017; 4.13 Pathname Resolution(6).)  For example:

          >>> splitroot('/home/sam')
          ('', '/', 'home/sam')
          >>> splitroot('//home/sam')
          ('', '//', 'home/sam')
          >>> splitroot('///home/sam')
          ('', '/', '//home/sam')

     On Windows, 'drive' may be empty, a drive-letter name, a UNC share,
     or a device name.  The 'root' may be empty, a forward slash, or a
     backward slash.  For example:

          >>> splitroot('C:/Users/Sam')
          ('C:', '/', 'Users/Sam')
          >>> splitroot('//Server/Share/Users/Sam')
          ('//Server/Share', '/', 'Users/Sam')

     Added in version 3.12.

 -- Function: os.path.splitext (path, /)

     Split the pathname 'path' into a pair ‘(root, ext)’ such that ‘root
     + ext == path’, and the extension, 'ext', is empty or begins with a
     period and contains at most one period.

     If the path contains no extension, 'ext' will be ‘''’:

          >>> splitext('bar')
          ('bar', '')

     If the path contains an extension, then 'ext' will be set to this
     extension, including the leading period.  Note that previous
     periods will be ignored:

          >>> splitext('foo.bar.exe')
          ('foo.bar', '.exe')
          >>> splitext('/foo/bar.exe')
          ('/foo/bar', '.exe')

     Leading periods of the last component of the path are considered to
     be part of the root:

          >>> splitext('.cshrc')
          ('.cshrc', '')
          >>> splitext('/foo/....jpg')
          ('/foo/....jpg', '')

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Data: os.path.supports_unicode_filenames

     ‘True’ if arbitrary Unicode strings can be used as file names
     (within limitations imposed by the file system).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/genericpath.py

   (2) https://github.com/python/cpython/tree/3.13/Lib/posixpath.py

   (3) https://github.com/python/cpython/tree/3.13/Lib/ntpath.py

   (4) https://learn.microsoft.com/windows/dev-drive/

   (5) 
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13

   (6) 
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13


File: python.info,  Node: stat — Interpreting stat results,  Next: filecmp — File and Directory Comparisons,  Prev: os path — Common pathname manipulations,  Up: File and Directory Access

5.11.3 ‘stat’ — Interpreting ‘stat()’ results
---------------------------------------------

'Source code:' Lib/stat.py(1)

__________________________________________________________________

The ‘stat’ module defines constants and functions for interpreting the
results of *note os.stat(): 4a3, *note os.fstat(): dba. and *note
os.lstat(): 4a4. (if they exist).  For complete details about the
‘stat()’, ‘fstat()’ and ‘lstat()’ calls, consult the documentation for
your system.

Changed in version 3.4: The stat module is backed by a C implementation.

The ‘stat’ module defines the following functions to test for specific
file types:

 -- Function: stat.S_ISDIR (mode)

     Return non-zero if the mode is from a directory.

 -- Function: stat.S_ISCHR (mode)

     Return non-zero if the mode is from a character special device
     file.

 -- Function: stat.S_ISBLK (mode)

     Return non-zero if the mode is from a block special device file.

 -- Function: stat.S_ISREG (mode)

     Return non-zero if the mode is from a regular file.

 -- Function: stat.S_ISFIFO (mode)

     Return non-zero if the mode is from a FIFO (named pipe).

 -- Function: stat.S_ISLNK (mode)

     Return non-zero if the mode is from a symbolic link.

 -- Function: stat.S_ISSOCK (mode)

     Return non-zero if the mode is from a socket.

 -- Function: stat.S_ISDOOR (mode)

     Return non-zero if the mode is from a door.

     Added in version 3.4.

 -- Function: stat.S_ISPORT (mode)

     Return non-zero if the mode is from an event port.

     Added in version 3.4.

 -- Function: stat.S_ISWHT (mode)

     Return non-zero if the mode is from a whiteout.

     Added in version 3.4.

Two additional functions are defined for more general manipulation of
the file’s mode:

 -- Function: stat.S_IMODE (mode)

     Return the portion of the file’s mode that can be set by *note
     os.chmod(): 21b.—that is, the file’s permission bits, plus the
     sticky bit, set-group-id, and set-user-id bits (on systems that
     support them).

 -- Function: stat.S_IFMT (mode)

     Return the portion of the file’s mode that describes the file type
     (used by the ‘S_IS*()’ functions above).

Normally, you would use the ‘os.path.is*()’ functions for testing the
type of a file; the functions here are useful when you are doing
multiple tests of the same file and wish to avoid the overhead of the
‘stat()’ system call for each test.  These are also useful when checking
for information about a file that isn’t handled by *note os.path: a2,
like the tests for block and character devices.

Example:

     import os, sys
     from stat import *

     def walktree(top, callback):
         '''recursively descend the directory tree rooted at top,
            calling the callback function for each regular file'''

         for f in os.listdir(top):
             pathname = os.path.join(top, f)
             mode = os.lstat(pathname).st_mode
             if S_ISDIR(mode):
                 # It's a directory, recurse into it
                 walktree(pathname, callback)
             elif S_ISREG(mode):
                 # It's a file, call the callback function
                 callback(pathname)
             else:
                 # Unknown file type, print a message
                 print('Skipping %s' % pathname)

     def visitfile(file):
         print('visiting', file)

     if __name__ == '__main__':
         walktree(sys.argv[1], visitfile)

An additional utility function is provided to convert a file’s mode in a
human readable string:

 -- Function: stat.filemode (mode)

     Convert a file’s mode to a string of the form ‘-rwxrwxrwx’.

     Added in version 3.3.

     Changed in version 3.4: The function supports *note S_IFDOOR: ff4,
     *note S_IFPORT: ff5. and *note S_IFWHT: ff6.

All the variables below are simply symbolic indexes into the 10-tuple
returned by *note os.stat(): 4a3, *note os.fstat(): dba. or *note
os.lstat(): 4a4.

 -- Data: stat.ST_MODE

     Inode protection mode.

 -- Data: stat.ST_INO

     Inode number.

 -- Data: stat.ST_DEV

     Device inode resides on.

 -- Data: stat.ST_NLINK

     Number of links to the inode.

 -- Data: stat.ST_UID

     User id of the owner.

 -- Data: stat.ST_GID

     Group id of the owner.

 -- Data: stat.ST_SIZE

     Size in bytes of a plain file; amount of data waiting on some
     special files.

 -- Data: stat.ST_ATIME

     Time of last access.

 -- Data: stat.ST_MTIME

     Time of last modification.

 -- Data: stat.ST_CTIME

     The “ctime” as reported by the operating system.  On some systems
     (like Unix) is the time of the last metadata change, and, on others
     (like Windows), is the creation time (see platform documentation
     for details).

The interpretation of “file size” changes according to the file type.
For plain files this is the size of the file in bytes.  For FIFOs and
sockets under most flavors of Unix (including Linux in particular), the
“size” is the number of bytes waiting to be read at the time of the call
to *note os.stat(): 4a3, *note os.fstat(): dba, or *note os.lstat():
4a4.; this can sometimes be useful, especially for polling one of these
special files after a non-blocking open.  The meaning of the size field
for other character and block devices varies more, depending on the
implementation of the underlying system call.

The variables below define the flags used in the *note ST_MODE: ff3.
field.

Use of the functions above is more portable than use of the first set of
flags:

 -- Data: stat.S_IFSOCK

     Socket.

 -- Data: stat.S_IFLNK

     Symbolic link.

 -- Data: stat.S_IFREG

     Regular file.

 -- Data: stat.S_IFBLK

     Block device.

 -- Data: stat.S_IFDIR

     Directory.

 -- Data: stat.S_IFCHR

     Character device.

 -- Data: stat.S_IFIFO

     FIFO.

 -- Data: stat.S_IFDOOR

     Door.

     Added in version 3.4.

 -- Data: stat.S_IFPORT

     Event port.

     Added in version 3.4.

 -- Data: stat.S_IFWHT

     Whiteout.

     Added in version 3.4.

     Note: *note S_IFDOOR: ff4, *note S_IFPORT: ff5. or *note S_IFWHT:
     ff6. are defined as 0 when the platform does not have support for
     the file types.

The following flags can also be used in the 'mode' argument of *note
os.chmod(): 21b.:

 -- Data: stat.S_ISUID

     Set UID bit.

 -- Data: stat.S_ISGID

     Set-group-ID bit.  This bit has several special uses.  For a
     directory it indicates that BSD semantics is to be used for that
     directory: files created there inherit their group ID from the
     directory, not from the effective group ID of the creating process,
     and directories created there will also get the ‘S_ISGID’ bit set.
     For a file that does not have the group execution bit (*note
     S_IXGRP: 29cc.) set, the set-group-ID bit indicates mandatory
     file/record locking (see also *note S_ENFMT: 29cd.).

 -- Data: stat.S_ISVTX

     Sticky bit.  When this bit is set on a directory it means that a
     file in that directory can be renamed or deleted only by the owner
     of the file, by the owner of the directory, or by a privileged
     process.

 -- Data: stat.S_IRWXU

     Mask for file owner permissions.

 -- Data: stat.S_IRUSR

     Owner has read permission.

 -- Data: stat.S_IWUSR

     Owner has write permission.

 -- Data: stat.S_IXUSR

     Owner has execute permission.

 -- Data: stat.S_IRWXG

     Mask for group permissions.

 -- Data: stat.S_IRGRP

     Group has read permission.

 -- Data: stat.S_IWGRP

     Group has write permission.

 -- Data: stat.S_IXGRP

     Group has execute permission.

 -- Data: stat.S_IRWXO

     Mask for permissions for others (not in group).

 -- Data: stat.S_IROTH

     Others have read permission.

 -- Data: stat.S_IWOTH

     Others have write permission.

 -- Data: stat.S_IXOTH

     Others have execute permission.

 -- Data: stat.S_ENFMT

     System V file locking enforcement.  This flag is shared with *note
     S_ISGID: 29cb.: file/record locking is enforced on files that do
     not have the group execution bit (*note S_IXGRP: 29cc.) set.

 -- Data: stat.S_IREAD

     Unix V7 synonym for *note S_IRUSR: 29d0.

 -- Data: stat.S_IWRITE

     Unix V7 synonym for *note S_IWUSR: 29d1.

 -- Data: stat.S_IEXEC

     Unix V7 synonym for *note S_IXUSR: 29d2.

The following flags can be used in the 'flags' argument of *note
os.chflags(): 1131.:

 -- Data: stat.UF_SETTABLE

     All user settable flags.

     Added in version 3.13.

 -- Data: stat.UF_NODUMP

     Do not dump the file.

 -- Data: stat.UF_IMMUTABLE

     The file may not be changed.

 -- Data: stat.UF_APPEND

     The file may only be appended to.

 -- Data: stat.UF_OPAQUE

     The directory is opaque when viewed through a union stack.

 -- Data: stat.UF_NOUNLINK

     The file may not be renamed or deleted.

 -- Data: stat.UF_COMPRESSED

     The file is stored compressed (macOS 10.6+).

 -- Data: stat.UF_TRACKED

     Used for handling document IDs (macOS)

     Added in version 3.13.

 -- Data: stat.UF_DATAVAULT

     The file needs an entitlement for reading or writing (macOS 10.13+)

     Added in version 3.13.

 -- Data: stat.UF_HIDDEN

     The file should not be displayed in a GUI (macOS 10.5+).

 -- Data: stat.SF_SETTABLE

     All super-user changeable flags

     Added in version 3.13.

 -- Data: stat.SF_SUPPORTED

     All super-user supported flags

     *note Availability: 1ef7.: macOS

     Added in version 3.13.

 -- Data: stat.SF_SYNTHETIC

     All super-user read-only synthetic flags

     *note Availability: 1ef7.: macOS

     Added in version 3.13.

 -- Data: stat.SF_ARCHIVED

     The file may be archived.

 -- Data: stat.SF_IMMUTABLE

     The file may not be changed.

 -- Data: stat.SF_APPEND

     The file may only be appended to.

 -- Data: stat.SF_RESTRICTED

     The file needs an entitlement to write to (macOS 10.13+)

     Added in version 3.13.

 -- Data: stat.SF_NOUNLINK

     The file may not be renamed or deleted.

 -- Data: stat.SF_SNAPSHOT

     The file is a snapshot file.

 -- Data: stat.SF_FIRMLINK

     The file is a firmlink (macOS 10.15+)

     Added in version 3.13.

 -- Data: stat.SF_DATALESS

     The file is a dataless object (macOS 10.15+)

     Added in version 3.13.

See the *BSD or macOS systems man page ‘chflags(2)(2)’ for more
information.

On Windows, the following file attribute constants are available for use
when testing bits in the ‘st_file_attributes’ member returned by *note
os.stat(): 4a3.  See the Windows API documentation(3) for more detail on
the meaning of these constants.

 -- Data: stat.FILE_ATTRIBUTE_ARCHIVE
 -- Data: stat.FILE_ATTRIBUTE_COMPRESSED
 -- Data: stat.FILE_ATTRIBUTE_DEVICE
 -- Data: stat.FILE_ATTRIBUTE_DIRECTORY
 -- Data: stat.FILE_ATTRIBUTE_ENCRYPTED
 -- Data: stat.FILE_ATTRIBUTE_HIDDEN
 -- Data: stat.FILE_ATTRIBUTE_INTEGRITY_STREAM
 -- Data: stat.FILE_ATTRIBUTE_NORMAL
 -- Data: stat.FILE_ATTRIBUTE_NOT_CONTENT_INDEXED
 -- Data: stat.FILE_ATTRIBUTE_NO_SCRUB_DATA
 -- Data: stat.FILE_ATTRIBUTE_OFFLINE
 -- Data: stat.FILE_ATTRIBUTE_READONLY
 -- Data: stat.FILE_ATTRIBUTE_REPARSE_POINT
 -- Data: stat.FILE_ATTRIBUTE_SPARSE_FILE
 -- Data: stat.FILE_ATTRIBUTE_SYSTEM
 -- Data: stat.FILE_ATTRIBUTE_TEMPORARY
 -- Data: stat.FILE_ATTRIBUTE_VIRTUAL

     Added in version 3.5.

On Windows, the following constants are available for comparing against
the ‘st_reparse_tag’ member returned by *note os.lstat(): 4a4.  These
are well-known constants, but are not an exhaustive list.

 -- Data: stat.IO_REPARSE_TAG_SYMLINK
 -- Data: stat.IO_REPARSE_TAG_MOUNT_POINT
 -- Data: stat.IO_REPARSE_TAG_APPEXECLINK

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/stat.py

   (2) https://manpages.debian.org/chflags(2)

   (3) 
https://msdn.microsoft.com/en-us/library/windows/desktop/gg258117.aspx


File: python.info,  Node: filecmp — File and Directory Comparisons,  Next: tempfile — Generate temporary files and directories,  Prev: stat — Interpreting stat results,  Up: File and Directory Access

5.11.4 ‘filecmp’ — File and Directory Comparisons
-------------------------------------------------

'Source code:' Lib/filecmp.py(1)

__________________________________________________________________

The ‘filecmp’ module defines functions to compare files and directories,
with various optional time/correctness trade-offs.  For comparing files,
see also the *note difflib: 37. module.

The ‘filecmp’ module defines the following functions:

 -- Function: filecmp.cmp (f1, f2, shallow=True)

     Compare the files named 'f1' and 'f2', returning ‘True’ if they
     seem equal, ‘False’ otherwise.

     If 'shallow' is true and the *note os.stat(): 4a3. signatures (file
     type, size, and modification time) of both files are identical, the
     files are taken to be equal.

     Otherwise, the files are treated as different if their sizes or
     contents differ.

     Note that no external programs are called from this function,
     giving it portability and efficiency.

     This function uses a cache for past comparisons and the results,
     with cache entries invalidated if the *note os.stat(): 4a3.
     information for the file changes.  The entire cache may be cleared
     using *note clear_cache(): f76.

 -- Function: filecmp.cmpfiles (dir1, dir2, common, shallow=True)

     Compare the files in the two directories 'dir1' and 'dir2' whose
     names are given by 'common'.

     Returns three lists of file names: 'match', 'mismatch', 'errors'.
     'match' contains the list of files that match, 'mismatch' contains
     the names of those that don’t, and 'errors' lists the names of
     files which could not be compared.  Files are listed in 'errors' if
     they don’t exist in one of the directories, the user lacks
     permission to read them or if the comparison could not be done for
     some other reason.

     The 'shallow' parameter has the same meaning and default value as
     for *note filecmp.cmp(): 1771.

     For example, ‘cmpfiles('a', 'b', ['c', 'd/e'])’ will compare ‘a/c’
     with ‘b/c’ and ‘a/d/e’ with ‘b/d/e’.  ‘'c'’ and ‘'d/e'’ will each
     be in one of the three returned lists.

 -- Function: filecmp.clear_cache ()

     Clear the filecmp cache.  This may be useful if a file is compared
     so quickly after it is modified that it is within the mtime
     resolution of the underlying filesystem.

     Added in version 3.4.

* Menu:

* The dircmp class::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/filecmp.py


File: python.info,  Node: The dircmp class,  Up: filecmp — File and Directory Comparisons

5.11.4.1 The ‘dircmp’ class
...........................

 -- Class: filecmp.dircmp (a, b, ignore=None, hide=None, *,
          shallow=True)

     Construct a new directory comparison object, to compare the
     directories 'a' and 'b'.  'ignore' is a list of names to ignore,
     and defaults to *note filecmp.DEFAULT_IGNORES: f77.  'hide' is a
     list of names to hide, and defaults to ‘[os.curdir, os.pardir]’.

     The ‘dircmp’ class compares files by doing 'shallow' comparisons as
     described for *note filecmp.cmp(): 1771. by default using the
     'shallow' parameter.

     Changed in version 3.13: Added the 'shallow' parameter.

     The ‘dircmp’ class provides the following methods:

      -- Method: report ()

          Print (to *note sys.stdout: aec.) a comparison between 'a' and
          'b'.

      -- Method: report_partial_closure ()

          Print a comparison between 'a' and 'b' and common immediate
          subdirectories.

      -- Method: report_full_closure ()

          Print a comparison between 'a' and 'b' and common
          subdirectories (recursively).

     The ‘dircmp’ class offers a number of interesting attributes that
     may be used to get various bits of information about the directory
     trees being compared.

     Note that via *note __getattr__(): 4d6. hooks, all attributes are
     computed lazily, so there is no speed penalty if only those
     attributes which are lightweight to compute are used.

      -- Attribute: left

          The directory 'a'.

      -- Attribute: right

          The directory 'b'.

      -- Attribute: left_list

          Files and subdirectories in 'a', filtered by 'hide' and
          'ignore'.

      -- Attribute: right_list

          Files and subdirectories in 'b', filtered by 'hide' and
          'ignore'.

      -- Attribute: common

          Files and subdirectories in both 'a' and 'b'.

      -- Attribute: left_only

          Files and subdirectories only in 'a'.

      -- Attribute: right_only

          Files and subdirectories only in 'b'.

      -- Attribute: common_dirs

          Subdirectories in both 'a' and 'b'.

      -- Attribute: common_files

          Files in both 'a' and 'b'.

      -- Attribute: common_funny

          Names in both 'a' and 'b', such that the type differs between
          the directories, or names for which *note os.stat(): 4a3.
          reports an error.

      -- Attribute: same_files

          Files which are identical in both 'a' and 'b', using the
          class’s file comparison operator.

      -- Attribute: diff_files

          Files which are in both 'a' and 'b', whose contents differ
          according to the class’s file comparison operator.

      -- Attribute: funny_files

          Files which are in both 'a' and 'b', but could not be
          compared.

      -- Attribute: subdirs

          A dictionary mapping names in *note common_dirs: 2a15. to
          ‘dircmp’ instances (or MyDirCmp instances if this instance is
          of type MyDirCmp, a subclass of ‘dircmp’).

          Changed in version 3.10: Previously entries were always
          ‘dircmp’ instances.  Now entries are the same type as 'self',
          if 'self' is a subclass of ‘dircmp’.

 -- Data: filecmp.DEFAULT_IGNORES

     Added in version 3.4.

     List of directories ignored by *note dircmp: f78. by default.

Here is a simplified example of using the ‘subdirs’ attribute to search
recursively through two directories to show common different files:

     >>> from filecmp import dircmp
     >>> def print_diff_files(dcmp):
     ...     for name in dcmp.diff_files:
     ...         print("diff_file %s found in %s and %s" % (name, dcmp.left,
     ...               dcmp.right))
     ...     for sub_dcmp in dcmp.subdirs.values():
     ...         print_diff_files(sub_dcmp)
     ...
     >>> dcmp = dircmp('dir1', 'dir2')
     >>> print_diff_files(dcmp)


File: python.info,  Node: tempfile — Generate temporary files and directories,  Next: glob — Unix style pathname pattern expansion,  Prev: filecmp — File and Directory Comparisons,  Up: File and Directory Access

5.11.5 ‘tempfile’ — Generate temporary files and directories
------------------------------------------------------------

'Source code:' Lib/tempfile.py(1)

__________________________________________________________________

This module creates temporary files and directories.  It works on all
supported platforms.  *note TemporaryFile: 2a1e, *note
NamedTemporaryFile: 4c9, *note TemporaryDirectory: 127a, and *note
SpooledTemporaryFile: 696. are high-level interfaces which provide
automatic cleanup and can be used as *note context managers: 5d7.  *note
mkstemp(): 2a1f. and *note mkdtemp(): 21f. are lower-level functions
which require manual cleanup.

All the user-callable functions and constructors take additional
arguments which allow direct control over the location and name of
temporary files and directories.  Files names used by this module
include a string of random characters which allows those files to be
securely created in shared temporary directories.  To maintain backward
compatibility, the argument order is somewhat odd; it is recommended to
use keyword arguments for clarity.

The module defines the following user-callable items:

 -- Function: tempfile.TemporaryFile (mode='w+b', buffering=-1,
          encoding=None, newline=None, suffix=None, prefix=None,
          dir=None, *, errors=None)

     Return a *note file-like object: 15f4. that can be used as a
     temporary storage area.  The file is created securely, using the
     same rules as *note mkstemp(): 2a1f.  It will be destroyed as soon
     as it is closed (including an implicit close when the object is
     garbage collected).  Under Unix, the directory entry for the file
     is either not created at all or is removed immediately after the
     file is created.  Other platforms do not support this; your code
     should not rely on a temporary file created using this function
     having or not having a visible name in the file system.

     The resulting object can be used as a *note context manager: 5d7.
     (see *note Examples: 2a20.).  On completion of the context or
     destruction of the file object the temporary file will be removed
     from the filesystem.

     The 'mode' parameter defaults to ‘'w+b'’ so that the file created
     can be read and written without being closed.  Binary mode is used
     so that it behaves consistently on all platforms without regard for
     the data that is stored.  'buffering', 'encoding', 'errors' and
     'newline' are interpreted as for *note open(): 51f.

     The 'dir', 'prefix' and 'suffix' parameters have the same meaning
     and defaults as with *note mkstemp(): 2a1f.

     The returned object is a true file object on POSIX platforms.  On
     other platforms, it is a file-like object whose ‘file’ attribute is
     the underlying true file object.

     The *note os.O_TMPFILE: fac. flag is used if it is available and
     works (Linux-specific, requires Linux kernel 3.11 or later).

     On platforms that are neither Posix nor Cygwin, TemporaryFile is an
     alias for NamedTemporaryFile.

     Raises an *note auditing event: 1a15. ‘tempfile.mkstemp’ with
     argument ‘fullpath’.

     Changed in version 3.5: The *note os.O_TMPFILE: fac. flag is now
     used if available.

     Changed in version 3.8: Added 'errors' parameter.

 -- Function: tempfile.NamedTemporaryFile (mode='w+b', buffering=-1,
          encoding=None, newline=None, suffix=None, prefix=None,
          dir=None, delete=True, *, errors=None, delete_on_close=True)

     This function operates exactly as *note TemporaryFile(): 2a1e.
     does, except the following differences:

        * This function returns a file that is guaranteed to have a
          visible name in the file system.

        * To manage the named file, it extends the parameters of *note
          TemporaryFile(): 2a1e. with 'delete' and 'delete_on_close'
          parameters that determine whether and how the named file
          should be automatically deleted.

     The returned object is always a *note file-like object: 15f4. whose
     ‘file’ attribute is the underlying true file object.  This
     file-like object can be used in a *note with: 5d5. statement, just
     like a normal file.  The name of the temporary file can be
     retrieved from the ‘name’ attribute of the returned file-like
     object.  On Unix, unlike with the *note TemporaryFile(): 2a1e, the
     directory entry does not get unlinked immediately after the file
     creation.

     If 'delete' is true (the default) and 'delete_on_close' is true
     (the default), the file is deleted as soon as it is closed.  If
     'delete' is true and 'delete_on_close' is false, the file is
     deleted on context manager exit only, or else when the *note
     file-like object: 15f4. is finalized.  Deletion is not always
     guaranteed in this case (see *note object.__del__(): 1038.).  If
     'delete' is false, the value of 'delete_on_close' is ignored.

     Therefore to use the name of the temporary file to reopen the file
     after closing it, either make sure not to delete the file upon
     closure (set the 'delete' parameter to be false) or, in case the
     temporary file is created in a *note with: 5d5. statement, set the
     'delete_on_close' parameter to be false.  The latter approach is
     recommended as it provides assistance in automatic cleaning of the
     temporary file upon the context manager exit.

     Opening the temporary file again by its name while it is still open
     works as follows:

        * On POSIX the file can always be opened again.

        * On Windows, make sure that at least one of the following
          conditions are fulfilled:

             * 'delete' is false

             * additional open shares delete access (e.g.  by calling
               *note os.open(): dc0. with the flag ‘O_TEMPORARY’)

             * 'delete' is true but 'delete_on_close' is false.  Note,
               that in this case the additional opens that do not share
               delete access (e.g.  created via builtin *note open():
               51f.) must be closed before exiting the context manager,
               else the *note os.unlink(): 1139. call on context manager
               exit will fail with a *note PermissionError: d6b.

     On Windows, if 'delete_on_close' is false, and the file is created
     in a directory for which the user lacks delete access, then the
     *note os.unlink(): 1139. call on exit of the context manager will
     fail with a *note PermissionError: d6b.  This cannot happen when
     'delete_on_close' is true because delete access is requested by the
     open, which fails immediately if the requested access is not
     granted.

     On POSIX (only), a process that is terminated abruptly with SIGKILL
     cannot automatically delete any NamedTemporaryFiles it created.

     Raises an *note auditing event: 1a15. ‘tempfile.mkstemp’ with
     argument ‘fullpath’.

     Changed in version 3.8: Added 'errors' parameter.

     Changed in version 3.12: Added 'delete_on_close' parameter.

 -- Class: tempfile.SpooledTemporaryFile (max_size=0, mode='w+b',
          buffering=-1, encoding=None, newline=None, suffix=None,
          prefix=None, dir=None, *, errors=None)

     This class operates exactly as *note TemporaryFile(): 2a1e. does,
     except that data is spooled in memory until the file size exceeds
     'max_size', or until the file’s *note fileno(): 15f5. method is
     called, at which point the contents are written to disk and
     operation proceeds as with ‘TemporaryFile()’.

      -- Method: rollover ()

          The resulting file has one additional method, ‘rollover()’,
          which causes the file to roll over to an on-disk file
          regardless of its size.

     The returned object is a file-like object whose ‘_file’ attribute
     is either an *note io.BytesIO: ed8. or *note io.TextIOWrapper: 7bf.
     object (depending on whether binary or text 'mode' was specified)
     or a true file object, depending on whether *note rollover(): 2a21.
     has been called.  This file-like object can be used in a *note
     with: 5d5. statement, just like a normal file.

     Changed in version 3.3: the truncate method now accepts a 'size'
     argument.

     Changed in version 3.8: Added 'errors' parameter.

     Changed in version 3.11: Fully implements the *note
     io.BufferedIOBase: 697. and *note io.TextIOBase: 698. abstract base
     classes (depending on whether binary or text 'mode' was specified).

 -- Class: tempfile.TemporaryDirectory (suffix=None, prefix=None,
          dir=None, ignore_cleanup_errors=False, *, delete=True)

     This class securely creates a temporary directory using the same
     rules as *note mkdtemp(): 21f.  The resulting object can be used as
     a *note context manager: 5d7. (see *note Examples: 2a20.).  On
     completion of the context or destruction of the temporary directory
     object, the newly created temporary directory and all its contents
     are removed from the filesystem.

      -- Attribute: name

          The directory name can be retrieved from the ‘name’ attribute
          of the returned object.  When the returned object is used as a
          *note context manager: 5d7, the ‘name’ will be assigned to the
          target of the ‘as’ clause in the *note with: 5d5. statement,
          if there is one.

      -- Method: cleanup ()

          The directory can be explicitly cleaned up by calling the
          ‘cleanup()’ method.  If 'ignore_cleanup_errors' is true, any
          unhandled exceptions during explicit or implicit cleanup (such
          as a *note PermissionError: d6b. removing open files on
          Windows) will be ignored, and the remaining removable items
          deleted on a “best-effort” basis.  Otherwise, errors will be
          raised in whatever context cleanup occurs (the ‘cleanup()’
          call, exiting the context manager, when the object is
          garbage-collected or during interpreter shutdown).

     The 'delete' parameter can be used to disable cleanup of the
     directory tree upon exiting the context.  While it may seem unusual
     for a context manager to disable the action taken when exiting the
     context, it can be useful during debugging or when you need your
     cleanup behavior to be conditional based on other logic.

     Raises an *note auditing event: 1a15. ‘tempfile.mkdtemp’ with
     argument ‘fullpath’.

     Added in version 3.2.

     Changed in version 3.10: Added 'ignore_cleanup_errors' parameter.

     Changed in version 3.12: Added the 'delete' parameter.

 -- Function: tempfile.mkstemp (suffix=None, prefix=None, dir=None,
          text=False)

     Creates a temporary file in the most secure manner possible.  There
     are no race conditions in the file’s creation, assuming that the
     platform properly implements the *note os.O_EXCL: 2a24. flag for
     *note os.open(): dc0.  The file is readable and writable only by
     the creating user ID. If the platform uses permission bits to
     indicate whether a file is executable, the file is executable by no
     one.

     The file descriptor is *note not inherited by child processes: f30.

     Unlike *note TemporaryFile(): 2a1e, the user of ‘mkstemp()’ is
     responsible for deleting the temporary file when done with it.

     If 'suffix' is not ‘None’, the file name will end with that suffix,
     otherwise there will be no suffix.  ‘mkstemp()’ does not put a dot
     between the file name and the suffix; if you need one, put it at
     the beginning of 'suffix'.

     If 'prefix' is not ‘None’, the file name will begin with that
     prefix; otherwise, a default prefix is used.  The default is the
     return value of *note gettempprefix(): 2a25. or *note
     gettempprefixb(): 2a26, as appropriate.

     If 'dir' is not ‘None’, the file will be created in that directory;
     otherwise, a default directory is used.  The default directory is
     chosen from a platform-dependent list, but the user of the
     application can control the directory location by setting the
     'TMPDIR', 'TEMP' or 'TMP' environment variables.  There is thus no
     guarantee that the generated filename will have any nice
     properties, such as not requiring quoting when passed to external
     commands via ‘os.popen()’.

     If any of 'suffix', 'prefix', and 'dir' are not ‘None’, they must
     be the same type.  If they are bytes, the returned name will be
     bytes instead of str.  If you want to force a bytes return value
     with otherwise default behavior, pass ‘suffix=b''’.

     If 'text' is specified and true, the file is opened in text mode.
     Otherwise, (the default) the file is opened in binary mode.

     ‘mkstemp()’ returns a tuple containing an OS-level handle to an
     open file (as would be returned by *note os.open(): dc0.) and the
     absolute pathname of that file, in that order.

     Raises an *note auditing event: 1a15. ‘tempfile.mkstemp’ with
     argument ‘fullpath’.

     Changed in version 3.5: 'suffix', 'prefix', and 'dir' may now be
     supplied in bytes in order to obtain a bytes return value.  Prior
     to this, only str was allowed.  'suffix' and 'prefix' now accept
     and default to ‘None’ to cause an appropriate default value to be
     used.

     Changed in version 3.6: The 'dir' parameter now accepts a *note
     path-like object: 2a0.

 -- Function: tempfile.mkdtemp (suffix=None, prefix=None, dir=None)

     Creates a temporary directory in the most secure manner possible.
     There are no race conditions in the directory’s creation.  The
     directory is readable, writable, and searchable only by the
     creating user ID.

     The user of ‘mkdtemp()’ is responsible for deleting the temporary
     directory and its contents when done with it.

     The 'prefix', 'suffix', and 'dir' arguments are the same as for
     *note mkstemp(): 2a1f.

     ‘mkdtemp()’ returns the absolute pathname of the new directory.

     Raises an *note auditing event: 1a15. ‘tempfile.mkdtemp’ with
     argument ‘fullpath’.

     Changed in version 3.5: 'suffix', 'prefix', and 'dir' may now be
     supplied in bytes in order to obtain a bytes return value.  Prior
     to this, only str was allowed.  'suffix' and 'prefix' now accept
     and default to ‘None’ to cause an appropriate default value to be
     used.

     Changed in version 3.6: The 'dir' parameter now accepts a *note
     path-like object: 2a0.

     Changed in version 3.12: ‘mkdtemp()’ now always returns an absolute
     path, even if 'dir' is relative.

 -- Function: tempfile.gettempdir ()

     Return the name of the directory used for temporary files.  This
     defines the default value for the 'dir' argument to all functions
     in this module.

     Python searches a standard list of directories to find one which
     the calling user can create files in.  The list is:

       1. The directory named by the ‘TMPDIR’ environment variable.

       2. The directory named by the ‘TEMP’ environment variable.

       3. The directory named by the ‘TMP’ environment variable.

       4. A platform-specific location:

             * On Windows, the directories ‘C:\TEMP’, ‘C:\TMP’, ‘\TEMP’,
               and ‘\TMP’, in that order.

             * On all other platforms, the directories ‘/tmp’,
               ‘/var/tmp’, and ‘/usr/tmp’, in that order.

       5. As a last resort, the current working directory.

     The result of this search is cached, see the description of *note
     tempdir: 1a38. below.

     Changed in version 3.10: Always returns a str.  Previously it would
     return any *note tempdir: 1a38. value regardless of type so long as
     it was not ‘None’.

 -- Function: tempfile.gettempdirb ()

     Same as *note gettempdir(): 1a39. but the return value is in bytes.

     Added in version 3.5.

 -- Function: tempfile.gettempprefix ()

     Return the filename prefix used to create temporary files.  This
     does not contain the directory component.

 -- Function: tempfile.gettempprefixb ()

     Same as *note gettempprefix(): 2a25. but the return value is in
     bytes.

     Added in version 3.5.

The module uses a global variable to store the name of the directory
used for temporary files returned by *note gettempdir(): 1a39.  It can
be set directly to override the selection process, but this is
discouraged.  All functions in this module take a 'dir' argument which
can be used to specify the directory.  This is the recommended approach
that does not surprise other unsuspecting code by changing global API
behavior.

 -- Data: tempfile.tempdir

     When set to a value other than ‘None’, this variable defines the
     default value for the 'dir' argument to the functions defined in
     this module, including its type, bytes or str.  It cannot be a
     *note path-like object: 2a0.

     If ‘tempdir’ is ‘None’ (the default) at any call to any of the
     above functions except *note gettempprefix(): 2a25. it is
     initialized following the algorithm described in *note
     gettempdir(): 1a39.

          Note: Beware that if you set ‘tempdir’ to a bytes value, there
          is a nasty side effect: The global default return type of
          *note mkstemp(): 2a1f. and *note mkdtemp(): 21f. changes to
          bytes when no explicit ‘prefix’, ‘suffix’, or ‘dir’ arguments
          of type str are supplied.  Please do not write code expecting
          or depending on this.  This awkward behavior is maintained for
          compatibility with the historical implementation.

* Menu:

* Examples: Examples<5>.
* Deprecated functions and variables::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tempfile.py


File: python.info,  Node: Examples<5>,  Next: Deprecated functions and variables,  Up: tempfile — Generate temporary files and directories

5.11.5.1 Examples
.................

Here are some examples of typical usage of the ‘tempfile’ module:

     >>> import tempfile

     # create a temporary file and write some data to it
     >>> fp = tempfile.TemporaryFile()
     >>> fp.write(b'Hello world!')
     # read data from file
     >>> fp.seek(0)
     >>> fp.read()
     b'Hello world!'
     # close the file, it will be removed
     >>> fp.close()

     # create a temporary file using a context manager
     >>> with tempfile.TemporaryFile() as fp:
     ...     fp.write(b'Hello world!')
     ...     fp.seek(0)
     ...     fp.read()
     b'Hello world!'
     >>>
     # file is now closed and removed

     # create a temporary file using a context manager
     # close the file, use the name to open the file again
     >>> with tempfile.NamedTemporaryFile(delete_on_close=False) as fp:
     ...     fp.write(b'Hello world!')
     ...     fp.close()
     ... # the file is closed, but not removed
     ... # open the file again by using its name
     ...     with open(fp.name, mode='rb') as f:
     ...         f.read()
     b'Hello world!'
     >>>
     # file is now removed

     # create a temporary directory using the context manager
     >>> with tempfile.TemporaryDirectory() as tmpdirname:
     ...     print('created temporary directory', tmpdirname)
     >>>
     # directory and contents have been removed


File: python.info,  Node: Deprecated functions and variables,  Prev: Examples<5>,  Up: tempfile — Generate temporary files and directories

5.11.5.2 Deprecated functions and variables
...........................................

A historical way to create temporary files was to first generate a file
name with the *note mktemp(): 19d6. function and then create a file
using this name.  Unfortunately this is not secure, because a different
process may create a file with this name in the time between the call to
‘mktemp()’ and the subsequent attempt to create the file by the first
process.  The solution is to combine the two steps and create the file
immediately.  This approach is used by *note mkstemp(): 2a1f. and the
other functions described above.

 -- Function: tempfile.mktemp (suffix='', prefix='tmp', dir=None)

     Deprecated since version 2.3: Use *note mkstemp(): 2a1f. instead.

     Return an absolute pathname of a file that did not exist at the
     time the call is made.  The 'prefix', 'suffix', and 'dir' arguments
     are similar to those of *note mkstemp(): 2a1f, except that bytes
     file names, ‘suffix=None’ and ‘prefix=None’ are not supported.

          Warning: Use of this function may introduce a security hole in
          your program.  By the time you get around to doing anything
          with the file name it returns, someone else may have beaten
          you to the punch.  ‘mktemp()’ usage can be replaced easily
          with *note NamedTemporaryFile(): 4c9, passing it the
          ‘delete=False’ parameter:

               >>> f = NamedTemporaryFile(delete=False)
               >>> f.name
               '/tmp/tmptjujjt'
               >>> f.write(b"Hello World!\n")
               13
               >>> f.close()
               >>> os.unlink(f.name)
               >>> os.path.exists(f.name)
               False


File: python.info,  Node: glob — Unix style pathname pattern expansion,  Next: fnmatch — Unix filename pattern matching,  Prev: tempfile — Generate temporary files and directories,  Up: File and Directory Access

5.11.6 ‘glob’ — Unix style pathname pattern expansion
-----------------------------------------------------

'Source code:' Lib/glob.py(1)

__________________________________________________________________

The ‘glob’ module finds pathnames using pattern matching rules similar
to the Unix shell.  No tilde expansion is done, but ‘*’, ‘?’, and
character ranges expressed with ‘[]’ will be correctly matched.  This is
done by using the *note os.scandir(): a6d. and *note fnmatch.fnmatch():
19fa. functions in concert, and not by actually invoking a subshell.

     Note: The pathnames are returned in no particular order.  If you
     need a specific order, sort the results.

Files beginning with a dot (‘.’) can only be matched by patterns that
also start with a dot, unlike *note fnmatch.fnmatch(): 19fa. or *note
pathlib.Path.glob(): 22d.  For tilde and shell variable expansion, use
*note os.path.expanduser(): a21. and *note os.path.expandvars(): 1427.

For a literal match, wrap the meta-characters in brackets.  For example,
‘'[?]'’ matches the character ‘'?'’.

The ‘glob’ module defines the following functions:

 -- Function: glob.glob (pathname, *, root_dir=None, dir_fd=None,
          recursive=False, include_hidden=False)

     Return a possibly empty list of path names that match 'pathname',
     which must be a string containing a path specification.  'pathname'
     can be either absolute (like ‘/usr/src/Python-1.5/Makefile’) or
     relative (like ‘../../Tools/*/*.gif’), and can contain shell-style
     wildcards.  Broken symlinks are included in the results (as in the
     shell).  Whether or not the results are sorted depends on the file
     system.  If a file that satisfies conditions is removed or added
     during the call of this function, whether a path name for that file
     will be included is unspecified.

     If 'root_dir' is not ‘None’, it should be a *note path-like object:
     2a0. specifying the root directory for searching.  It has the same
     effect on ‘glob()’ as changing the current directory before calling
     it.  If 'pathname' is relative, the result will contain paths
     relative to 'root_dir'.

     This function can support *note paths relative to directory
     descriptors: 112e. with the 'dir_fd' parameter.

     If 'recursive' is true, the pattern “‘**’” will match any files and
     zero or more directories, subdirectories and symbolic links to
     directories.  If the pattern is followed by an *note os.sep: 66d.
     or *note os.altsep: 66e. then files will not match.

     If 'include_hidden' is true, “‘**’” pattern will match hidden
     directories.

     Raises an *note auditing event: 1a15. ‘glob.glob’ with arguments
     ‘pathname’, ‘recursive’.

     Raises an *note auditing event: 1a15. ‘glob.glob/2’ with arguments
     ‘pathname’, ‘recursive’, ‘root_dir’, ‘dir_fd’.

          Note: Using the “‘**’” pattern in large directory trees may
          consume an inordinate amount of time.

          Note: This function may return duplicate path names if
          'pathname' contains multiple “‘**’” patterns and 'recursive'
          is true.

     Changed in version 3.5: Support for recursive globs using “‘**’”.

     Changed in version 3.10: Added the 'root_dir' and 'dir_fd'
     parameters.

     Changed in version 3.11: Added the 'include_hidden' parameter.

 -- Function: glob.iglob (pathname, *, root_dir=None, dir_fd=None,
          recursive=False, include_hidden=False)

     Return an *note iterator: 1ac. which yields the same values as
     *note glob(): 64. without actually storing them all simultaneously.

     Raises an *note auditing event: 1a15. ‘glob.glob’ with arguments
     ‘pathname’, ‘recursive’.

     Raises an *note auditing event: 1a15. ‘glob.glob/2’ with arguments
     ‘pathname’, ‘recursive’, ‘root_dir’, ‘dir_fd’.

          Note: This function may return duplicate path names if
          'pathname' contains multiple “‘**’” patterns and 'recursive'
          is true.

     Changed in version 3.5: Support for recursive globs using “‘**’”.

     Changed in version 3.10: Added the 'root_dir' and 'dir_fd'
     parameters.

     Changed in version 3.11: Added the 'include_hidden' parameter.

 -- Function: glob.escape (pathname)

     Escape all special characters (‘'?'’, ‘'*'’ and ‘'['’).  This is
     useful if you want to match an arbitrary literal string that may
     have special characters in it.  Special characters in drive/UNC
     sharepoints are not escaped, e.g.  on Windows ‘escape('//?/c:/Quo
     vadis?.txt')’ returns ‘'//?/c:/Quo vadis[?].txt'’.

     Added in version 3.4.

 -- Function: glob.translate (pathname, *, recursive=False,
          include_hidden=False, seps=None)

     Convert the given path specification to a regular expression for
     use with *note re.match(): 1273.  The path specification can
     contain shell-style wildcards.

     For example:

          >>> import glob, re
          >>>
          >>> regex = glob.translate('**/*.txt', recursive=True, include_hidden=True)
          >>> regex
          '(?s:(?:.+/)?[^/]*\\.txt)\\Z'
          >>> reobj = re.compile(regex)
          >>> reobj.match('foo/bar/baz.txt')
          <re.Match object; span=(0, 15), match='foo/bar/baz.txt'>

     Path separators and segments are meaningful to this function,
     unlike *note fnmatch.translate(): 1bd6.  By default wildcards do
     not match path separators, and ‘*’ pattern segments match precisely
     one path segment.

     If 'recursive' is true, the pattern segment “‘**’” will match any
     number of path segments.

     If 'include_hidden' is true, wildcards can match path segments that
     start with a dot (‘.’).

     A sequence of path separators may be supplied to the 'seps'
     argument.  If not given, *note os.sep: 66d. and *note altsep: 66e.
     (if available) are used.

     See also
     ........

     *note pathlib.PurePath.full_match(): 22b. and *note
     pathlib.Path.glob(): 22d. methods, which call this function to
     implement pattern matching and globbing.

     Added in version 3.13.

* Menu:

* Examples: Examples<6>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/glob.py


File: python.info,  Node: Examples<6>,  Up: glob — Unix style pathname pattern expansion

5.11.6.1 Examples
.................

Consider a directory containing the following files: ‘1.gif’, ‘2.txt’,
‘card.gif’ and a subdirectory ‘sub’ which contains only the file
‘3.txt’.  *note glob(): 64. will produce the following results.  Notice
how any leading components of the path are preserved.

     >>> import glob
     >>> glob.glob('./[0-9].*')
     ['./1.gif', './2.txt']
     >>> glob.glob('*.gif')
     ['1.gif', 'card.gif']
     >>> glob.glob('?.gif')
     ['1.gif']
     >>> glob.glob('**/*.txt', recursive=True)
     ['2.txt', 'sub/3.txt']
     >>> glob.glob('./**/', recursive=True)
     ['./', './sub/']

If the directory contains files starting with ‘.’ they won’t be matched
by default.  For example, consider a directory containing ‘card.gif’ and
‘.card.gif’:

     >>> import glob
     >>> glob.glob('*.gif')
     ['card.gif']
     >>> glob.glob('.c*')
     ['.card.gif']

See also
........

The *note fnmatch: 5c. module offers shell-style filename (not path)
expansion.

See also
........

The *note pathlib: a4. module offers high-level path objects.


File: python.info,  Node: fnmatch — Unix filename pattern matching,  Next: linecache — Random access to text lines,  Prev: glob — Unix style pathname pattern expansion,  Up: File and Directory Access

5.11.7 ‘fnmatch’ — Unix filename pattern matching
-------------------------------------------------

'Source code:' Lib/fnmatch.py(1)

__________________________________________________________________

This module provides support for Unix shell-style wildcards, which are
'not' the same as regular expressions (which are documented in the *note
re: b9. module).  The special characters used in shell-style wildcards
are:

Pattern          Meaning
                 
----------------------------------------------------------
                 
‘*’              matches everything
                 
                 
‘?’              matches any single character
                 
                 
‘[seq]’          matches any character in 'seq'
                 
                 
‘[!seq]’         matches any character not in 'seq'
                 

For a literal match, wrap the meta-characters in brackets.  For example,
‘'[?]'’ matches the character ‘'?'’.

Note that the filename separator (‘'/'’ on Unix) is 'not' special to
this module.  See module *note glob: 64. for pathname expansion (‘glob’
uses *note filter(): 19fc. to match pathname segments).  Similarly,
filenames starting with a period are not special for this module, and
are matched by the ‘*’ and ‘?’ patterns.

Unless stated otherwise, “filename string” and “pattern string” either
refer to *note str: 44f. or ‘ISO-8859-1’ encoded *note bytes: 1c2.
objects.  Note that the functions documented below do not allow to mix a
‘bytes’ pattern with a ‘str’ filename, and vice-versa.

Finally, note that *note functools.lru_cache(): 9fa. with a 'maxsize' of
32768 is used to cache the (typed) compiled regex patterns in the
following functions: *note fnmatch(): 5c, *note fnmatchcase(): 19fb,
*note filter(): 19fc.

 -- Function: fnmatch.fnmatch (name, pat)

     Test whether the filename string 'name' matches the pattern string
     'pat', returning ‘True’ or ‘False’.  Both parameters are
     case-normalized using *note os.path.normcase(): 29ab.  *note
     fnmatchcase(): 19fb. can be used to perform a case-sensitive
     comparison, regardless of whether that’s standard for the operating
     system.

     This example will print all file names in the current directory
     with the extension ‘.txt’:

          import fnmatch
          import os

          for file in os.listdir('.'):
              if fnmatch.fnmatch(file, '*.txt'):
                  print(file)

 -- Function: fnmatch.fnmatchcase (name, pat)

     Test whether the filename string 'name' matches the pattern string
     'pat', returning ‘True’ or ‘False’; the comparison is
     case-sensitive and does not apply *note os.path.normcase(): 29ab.

 -- Function: fnmatch.filter (names, pat)

     Construct a list from those elements of the *note iterable: 126d.
     of filename strings 'names' that match the pattern string 'pat'.
     It is the same as ‘[n for n in names if fnmatch(n, pat)]’, but
     implemented more efficiently.

 -- Function: fnmatch.translate (pat)

     Return the shell-style pattern 'pat' converted to a regular
     expression for using with *note re.match(): 1273.  The pattern is
     expected to be a *note str: 44f.

     Example:

          >>> import fnmatch, re
          >>>
          >>> regex = fnmatch.translate('*.txt')
          >>> regex
          '(?s:.*\\.txt)\\Z'
          >>> reobj = re.compile(regex)
          >>> reobj.match('foobar.txt')
          <re.Match object; span=(0, 10), match='foobar.txt'>

See also
........

Module *note glob: 64.

     Unix shell-style path expansion.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/fnmatch.py


File: python.info,  Node: linecache — Random access to text lines,  Next: shutil — High-level file operations,  Prev: fnmatch — Unix filename pattern matching,  Up: File and Directory Access

5.11.8 ‘linecache’ — Random access to text lines
------------------------------------------------

'Source code:' Lib/linecache.py(1)

__________________________________________________________________

The ‘linecache’ module allows one to get any line from a Python source
file, while attempting to optimize internally, using a cache, the common
case where many lines are read from a single file.  This is used by the
*note traceback: fe. module to retrieve source lines for inclusion in
the formatted traceback.

The *note tokenize.open(): 2a34. function is used to open files.  This
function uses *note tokenize.detect_encoding(): 2a35. to get the
encoding of the file; in the absence of an encoding token, the file
encoding defaults to UTF-8.

The ‘linecache’ module defines the following functions:

 -- Function: linecache.getline (filename, lineno, module_globals=None)

     Get line 'lineno' from file named 'filename'.  This function will
     never raise an exception — it will return ‘''’ on errors (the
     terminating newline character will be included for lines that are
     found).

     If a file named 'filename' is not found, the function first checks
     for a PEP 302(2) ‘__loader__’ in 'module_globals'.  If there is
     such a loader and it defines a ‘get_source’ method, then that
     determines the source lines (if ‘get_source()’ returns ‘None’, then
     ‘''’ is returned).  Finally, if 'filename' is a relative filename,
     it is looked up relative to the entries in the module search path,
     ‘sys.path’.

 -- Function: linecache.clearcache ()

     Clear the cache.  Use this function if you no longer need lines
     from files previously read using *note getline(): e56.

 -- Function: linecache.checkcache (filename=None)

     Check the cache for validity.  Use this function if files in the
     cache may have changed on disk, and you require the updated
     version.  If 'filename' is omitted, it will check all the entries
     in the cache.

 -- Function: linecache.lazycache (filename, module_globals)

     Capture enough detail about a non-file-based module to permit
     getting its lines later via *note getline(): e56. even if
     'module_globals' is ‘None’ in the later call.  This avoids doing
     I/O until a line is actually needed, without having to carry the
     module globals around indefinitely.

     Added in version 3.5.

Example:

     >>> import linecache
     >>> linecache.getline(linecache.__file__, 8)
     'import sys\n'

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/linecache.py

   (2) https://peps.python.org/pep-0302/


File: python.info,  Node: shutil — High-level file operations,  Prev: linecache — Random access to text lines,  Up: File and Directory Access

5.11.9 ‘shutil’ — High-level file operations
--------------------------------------------

'Source code:' Lib/shutil.py(1)

__________________________________________________________________

The ‘shutil’ module offers a number of high-level operations on files
and collections of files.  In particular, functions are provided which
support file copying and removal.  For operations on individual files,
see also the *note os: a1. module.

     Warning: Even the higher-level file copying functions (*note
     shutil.copy(): a68, *note shutil.copy2(): a69.) cannot copy all
     file metadata.

     On POSIX platforms, this means that file owner and group are lost
     as well as ACLs.  On Mac OS, the resource fork and other metadata
     are not used.  This means that resources will be lost and file type
     and creator codes will not be correct.  On Windows, file owners,
     ACLs and alternate data streams are not copied.

* Menu:

* Directory and files operations::
* Archiving operations::
* Querying the size of the output terminal::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/shutil.py


File: python.info,  Node: Directory and files operations,  Next: Archiving operations,  Up: shutil — High-level file operations

5.11.9.1 Directory and files operations
.......................................

 -- Function: shutil.copyfileobj (fsrc, fdst[, length])

     Copy the contents of the *note file-like object: 1208. 'fsrc' to
     the file-like object 'fdst'.  The integer 'length', if given, is
     the buffer size.  In particular, a negative 'length' value means to
     copy the data without looping over the source data in chunks; by
     default the data is read in chunks to avoid uncontrolled memory
     consumption.  Note that if the current file position of the 'fsrc'
     object is not 0, only the contents from the current file position
     to the end of the file will be copied.

 -- Function: shutil.copyfile (src, dst, *, follow_symlinks=True)

     Copy the contents (no metadata) of the file named 'src' to a file
     named 'dst' and return 'dst' in the most efficient way possible.
     'src' and 'dst' are *note path-like objects: 2a0. or path names
     given as strings.

     'dst' must be the complete target file name; look at *note copy():
     a68. for a copy that accepts a target directory path.  If 'src' and
     'dst' specify the same file, *note SameFileError: fd7. is raised.

     The destination location must be writable; otherwise, an *note
     OSError: 41a. exception will be raised.  If 'dst' already exists,
     it will be replaced.  Special files such as character or block
     devices and pipes cannot be copied with this function.

     If 'follow_symlinks' is false and 'src' is a symbolic link, a new
     symbolic link will be created instead of copying the file 'src'
     points to.

     Raises an *note auditing event: 1a15. ‘shutil.copyfile’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.3: *note IOError: 1090. used to be raised
     instead of *note OSError: 41a.  Added 'follow_symlinks' argument.
     Now returns 'dst'.

     Changed in version 3.4: Raise *note SameFileError: fd7. instead of
     *note Error: fd6.  Since the former is a subclass of the latter,
     this change is backward compatible.

     Changed in version 3.8: Platform-specific fast-copy syscalls may be
     used internally in order to copy the file more efficiently.  See
     *note Platform-dependent efficient copy operations: a6c. section.

 -- Exception: shutil.SpecialFileError

     This exception is raised when *note copyfile(): a67. or *note
     copytree(): a36. attempt to copy a named pipe.

     Added in version 2.7.

 -- Exception: shutil.SameFileError

     This exception is raised if source and destination in *note
     copyfile(): a67. are the same file.

     Added in version 3.4.

 -- Function: shutil.copymode (src, dst, *, follow_symlinks=True)

     Copy the permission bits from 'src' to 'dst'.  The file contents,
     owner, and group are unaffected.  'src' and 'dst' are *note
     path-like objects: 2a0. or path names given as strings.  If
     'follow_symlinks' is false, and both 'src' and 'dst' are symbolic
     links, ‘copymode()’ will attempt to modify the mode of 'dst' itself
     (rather than the file it points to).  This functionality is not
     available on every platform; please see *note copystat(): 1172. for
     more information.  If ‘copymode()’ cannot modify symbolic links on
     the local platform, and it is asked to do so, it will do nothing
     and return.

     Raises an *note auditing event: 1a15. ‘shutil.copymode’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.3: Added 'follow_symlinks' argument.

 -- Function: shutil.copystat (src, dst, *, follow_symlinks=True)

     Copy the permission bits, last access time, last modification time,
     and flags from 'src' to 'dst'.  On Linux, ‘copystat()’ also copies
     the “extended attributes” where possible.  The file contents,
     owner, and group are unaffected.  'src' and 'dst' are *note
     path-like objects: 2a0. or path names given as strings.

     If 'follow_symlinks' is false, and 'src' and 'dst' both refer to
     symbolic links, ‘copystat()’ will operate on the symbolic links
     themselves rather than the files the symbolic links refer
     to—reading the information from the 'src' symbolic link, and
     writing the information to the 'dst' symbolic link.

          Note: Not all platforms provide the ability to examine and
          modify symbolic links.  Python itself can tell you what
          functionality is locally available.

             * If ‘os.chmod in os.supports_follow_symlinks’ is ‘True’,
               ‘copystat()’ can modify the permission bits of a symbolic
               link.

             * If ‘os.utime in os.supports_follow_symlinks’ is ‘True’,
               ‘copystat()’ can modify the last access and modification
               times of a symbolic link.

             * If ‘os.chflags in os.supports_follow_symlinks’ is ‘True’,
               ‘copystat()’ can modify the flags of a symbolic link.
               (‘os.chflags’ is not available on all platforms.)

          On platforms where some or all of this functionality is
          unavailable, when asked to modify a symbolic link,
          ‘copystat()’ will copy everything it can.  ‘copystat()’ never
          returns failure.

          Please see *note os.supports_follow_symlinks: 113c. for more
          information.

     Raises an *note auditing event: 1a15. ‘shutil.copystat’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.3: Added 'follow_symlinks' argument and
     support for Linux extended attributes.

 -- Function: shutil.copy (src, dst, *, follow_symlinks=True)

     Copies the file 'src' to the file or directory 'dst'.  'src' and
     'dst' should be *note path-like objects: 2a0. or strings.  If 'dst'
     specifies a directory, the file will be copied into 'dst' using the
     base filename from 'src'.  If 'dst' specifies a file that already
     exists, it will be replaced.  Returns the path to the newly created
     file.

     If 'follow_symlinks' is false, and 'src' is a symbolic link, 'dst'
     will be created as a symbolic link.  If 'follow_symlinks' is true
     and 'src' is a symbolic link, 'dst' will be a copy of the file
     'src' refers to.

     *note copy(): a68. copies the file data and the file’s permission
     mode (see *note os.chmod(): 21b.).  Other metadata, like the file’s
     creation and modification times, is not preserved.  To preserve all
     file metadata from the original, use *note copy2(): a69. instead.

     Raises an *note auditing event: 1a15. ‘shutil.copyfile’ with
     arguments ‘src’, ‘dst’.

     Raises an *note auditing event: 1a15. ‘shutil.copymode’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.3: Added 'follow_symlinks' argument.  Now
     returns path to the newly created file.

     Changed in version 3.8: Platform-specific fast-copy syscalls may be
     used internally in order to copy the file more efficiently.  See
     *note Platform-dependent efficient copy operations: a6c. section.

 -- Function: shutil.copy2 (src, dst, *, follow_symlinks=True)

     Identical to *note copy(): a68. except that ‘copy2()’ also attempts
     to preserve file metadata.

     When 'follow_symlinks' is false, and 'src' is a symbolic link,
     ‘copy2()’ attempts to copy all metadata from the 'src' symbolic
     link to the newly created 'dst' symbolic link.  However, this
     functionality is not available on all platforms.  On platforms
     where some or all of this functionality is unavailable, ‘copy2()’
     will preserve all the metadata it can; ‘copy2()’ never raises an
     exception because it cannot preserve file metadata.

     ‘copy2()’ uses *note copystat(): 1172. to copy the file metadata.
     Please see ‘copystat()’ for more information about platform support
     for modifying symbolic link metadata.

     Raises an *note auditing event: 1a15. ‘shutil.copyfile’ with
     arguments ‘src’, ‘dst’.

     Raises an *note auditing event: 1a15. ‘shutil.copystat’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.3: Added 'follow_symlinks' argument, try to
     copy extended file system attributes too (currently Linux only).
     Now returns path to the newly created file.

     Changed in version 3.8: Platform-specific fast-copy syscalls may be
     used internally in order to copy the file more efficiently.  See
     *note Platform-dependent efficient copy operations: a6c. section.

 -- Function: shutil.ignore_patterns (*patterns)

     This factory function creates a function that can be used as a
     callable for *note copytree(): a36.'s 'ignore' argument, ignoring
     files and directories that match one of the glob-style 'patterns'
     provided.  See the example below.

 -- Function: shutil.copytree (src, dst, symlinks=False, ignore=None,
          copy_function=copy2, ignore_dangling_symlinks=False,
          dirs_exist_ok=False)

     Recursively copy an entire directory tree rooted at 'src' to a
     directory named 'dst' and return the destination directory.  All
     intermediate directories needed to contain 'dst' will also be
     created by default.

     Permissions and times of directories are copied with *note
     copystat(): 1172, individual files are copied using *note copy2():
     a69.

     If 'symlinks' is true, symbolic links in the source tree are
     represented as symbolic links in the new tree and the metadata of
     the original links will be copied as far as the platform allows; if
     false or omitted, the contents and metadata of the linked files are
     copied to the new tree.

     When 'symlinks' is false, if the file pointed to by the symlink
     doesn’t exist, an exception will be added in the list of errors
     raised in an *note Error: fd6. exception at the end of the copy
     process.  You can set the optional 'ignore_dangling_symlinks' flag
     to true if you want to silence this exception.  Notice that this
     option has no effect on platforms that don’t support *note
     os.symlink(): 1138.

     If 'ignore' is given, it must be a callable that will receive as
     its arguments the directory being visited by ‘copytree()’, and a
     list of its contents, as returned by *note os.listdir(): 113e.
     Since ‘copytree()’ is called recursively, the 'ignore' callable
     will be called once for each directory that is copied.  The
     callable must return a sequence of directory and file names
     relative to the current directory (i.e.  a subset of the items in
     its second argument); these names will then be ignored in the copy
     process.  *note ignore_patterns(): 2a3c. can be used to create such
     a callable that ignores names based on glob-style patterns.

     If exception(s) occur, an *note Error: fd6. is raised with a list
     of reasons.

     If 'copy_function' is given, it must be a callable that will be
     used to copy each file.  It will be called with the source path and
     the destination path as arguments.  By default, *note copy2(): a69.
     is used, but any function that supports the same signature (like
     *note copy(): a68.) can be used.

     If 'dirs_exist_ok' is false (the default) and 'dst' already exists,
     a *note FileExistsError: 105b. is raised.  If 'dirs_exist_ok' is
     true, the copying operation will continue if it encounters existing
     directories, and files within the 'dst' tree will be overwritten by
     corresponding files from the 'src' tree.

     Raises an *note auditing event: 1a15. ‘shutil.copytree’ with
     arguments ‘src’, ‘dst’.

     Changed in version 3.2: Added the 'copy_function' argument to be
     able to provide a custom copy function.  Added the
     'ignore_dangling_symlinks' argument to silence dangling symlinks
     errors when 'symlinks' is false.

     Changed in version 3.3: Copy metadata when 'symlinks' is false.
     Now returns 'dst'.

     Changed in version 3.8: Platform-specific fast-copy syscalls may be
     used internally in order to copy the file more efficiently.  See
     *note Platform-dependent efficient copy operations: a6c. section.

     Changed in version 3.8: Added the 'dirs_exist_ok' parameter.

 -- Function: shutil.rmtree (path, ignore_errors=False, onerror=None, *,
          onexc=None, dir_fd=None)

     Delete an entire directory tree; 'path' must point to a directory
     (but not a symbolic link to a directory).  If 'ignore_errors' is
     true, errors resulting from failed removals will be ignored; if
     false or omitted, such errors are handled by calling a handler
     specified by 'onexc' or 'onerror' or, if both are omitted,
     exceptions are propagated to the caller.

     This function can support *note paths relative to directory
     descriptors: 112e.

          Note: On platforms that support the necessary fd-based
          functions a symlink attack resistant version of ‘rmtree()’ is
          used by default.  On other platforms, the ‘rmtree()’
          implementation is susceptible to a symlink attack: given
          proper timing and circumstances, attackers can manipulate
          symlinks on the filesystem to delete files they wouldn’t be
          able to access otherwise.  Applications can use the *note
          rmtree.avoids_symlink_attacks: 2a3d. function attribute to
          determine which case applies.

     If 'onexc' is provided, it must be a callable that accepts three
     parameters: 'function', 'path', and 'excinfo'.

     The first parameter, 'function', is the function which raised the
     exception; it depends on the platform and implementation.  The
     second parameter, 'path', will be the path name passed to
     'function'.  The third parameter, 'excinfo', is the exception that
     was raised.  Exceptions raised by 'onexc' will not be caught.

     The deprecated 'onerror' is similar to 'onexc', except that the
     third parameter it receives is the tuple returned from *note
     sys.exc_info(): 68d.

     See also
     ........

     *note rmtree example: 2a3e. for an example of handling the removal
     of a directory tree that contains read-only files.

     Raises an *note auditing event: 1a15. ‘shutil.rmtree’ with
     arguments ‘path’, ‘dir_fd’.

     Changed in version 3.3: Added a symlink attack resistant version
     that is used automatically if platform supports fd-based functions.

     Changed in version 3.8: On Windows, will no longer delete the
     contents of a directory junction before removing the junction.

     Changed in version 3.11: Added the 'dir_fd' parameter.

     Changed in version 3.12: Added the 'onexc' parameter, deprecated
     'onerror'.

     Changed in version 3.13: ‘rmtree()’ now ignores *note
     FileNotFoundError: 42e. exceptions for all but the top-level path.
     Exceptions other than *note OSError: 41a. and subclasses of
     ‘OSError’ are now always propagated to the caller.

      -- Attribute: rmtree.avoids_symlink_attacks

          Indicates whether the current platform and implementation
          provides a symlink attack resistant version of ‘rmtree()’.
          Currently this is only true for platforms supporting fd-based
          directory access functions.

          Added in version 3.3.

 -- Function: shutil.move (src, dst, copy_function=copy2)

     Recursively move a file or directory ('src') to another location
     and return the destination.

     If 'dst' is an existing directory or a symlink to a directory, then
     'src' is moved inside that directory.  The destination path in that
     directory must not already exist.

     If 'dst' already exists but is not a directory, it may be
     overwritten depending on *note os.rename(): 1135. semantics.

     If the destination is on the current filesystem, then *note
     os.rename(): 1135. is used.  Otherwise, 'src' is copied to the
     destination using 'copy_function' and then removed.  In case of
     symlinks, a new symlink pointing to the target of 'src' will be
     created as the destination and 'src' will be removed.

     If 'copy_function' is given, it must be a callable that takes two
     arguments, 'src' and the destination, and will be used to copy
     'src' to the destination if *note os.rename(): 1135. cannot be
     used.  If the source is a directory, *note copytree(): a36. is
     called, passing it the 'copy_function'.  The default
     'copy_function' is *note copy2(): a69.  Using *note copy(): a68. as
     the 'copy_function' allows the move to succeed when it is not
     possible to also copy the metadata, at the expense of not copying
     any of the metadata.

     Raises an *note auditing event: 1a15. ‘shutil.move’ with arguments
     ‘src’, ‘dst’.

     Changed in version 3.3: Added explicit symlink handling for foreign
     filesystems, thus adapting it to the behavior of GNU’s ‘mv’.  Now
     returns 'dst'.

     Changed in version 3.5: Added the 'copy_function' keyword argument.

     Changed in version 3.8: Platform-specific fast-copy syscalls may be
     used internally in order to copy the file more efficiently.  See
     *note Platform-dependent efficient copy operations: a6c. section.

     Changed in version 3.9: Accepts a *note path-like object: 2a0. for
     both 'src' and 'dst'.

 -- Function: shutil.disk_usage (path)

     Return disk usage statistics about the given path as a *note named
     tuple: 651. with the attributes 'total', 'used' and 'free', which
     are the amount of total, used and free space, in bytes.  'path' may
     be a file or a directory.

          Note: On Unix filesystems, 'path' must point to a path within
          a 'mounted' filesystem partition.  On those platforms, CPython
          doesn’t attempt to retrieve disk usage information from
          non-mounted filesystems.

     Added in version 3.3.

     Changed in version 3.8: On Windows, 'path' can now be a file or
     directory.

     *note Availability: 1ef7.: Unix, Windows.

 -- Function: shutil.chown (path, user=None, group=None, *, dir_fd=None,
          follow_symlinks=True)

     Change owner 'user' and/or 'group' of the given 'path'.

     'user' can be a system user name or a uid; the same applies to
     'group'.  At least one argument is required.

     See also *note os.chown(): 1132, the underlying function.

     Raises an *note auditing event: 1a15. ‘shutil.chown’ with arguments
     ‘path’, ‘user’, ‘group’.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

     Changed in version 3.13: Added 'dir_fd' and 'follow_symlinks'
     parameters.

 -- Function: shutil.which (cmd, mode=os.F_OK | os.X_OK, path=None)

     Return the path to an executable which would be run if the given
     'cmd' was called.  If no 'cmd' would be called, return ‘None’.

     'mode' is a permission mask passed to *note os.access(): 1130, by
     default determining if the file exists and is executable.

     'path' is a “‘PATH’ string” specifying the directories to look in,
     delimited by *note os.pathsep: 1eec.  When no 'path' is specified,
     the ‘PATH’ environment variable is read from *note os.environ:
     11fe, falling back to *note os.defpath: 1b92. if it is not set.

     If 'cmd' contains a directory component, ‘which()’ only checks the
     specified path directly and does not search the directories listed
     in 'path' or in the system’s ‘PATH’ environment variable.

     On Windows, the current directory is prepended to the 'path' if
     'mode' does not include ‘os.X_OK’.  When the 'mode' does include
     ‘os.X_OK’, the Windows API ‘NeedCurrentDirectoryForExePathW’ will
     be consulted to determine if the current directory should be
     prepended to 'path'.  To avoid consulting the current working
     directory for executables: set the environment variable
     ‘NoDefaultCurrentDirectoryInExePath’.

     Also on Windows, the ‘PATHEXT’ environment variable is used to
     resolve commands that may not already include an extension.  For
     example, if you call ‘shutil.which("python")’, ‘which()’ will
     search ‘PATHEXT’ to know that it should look for ‘python.exe’
     within the 'path' directories.  For example, on Windows:

          >>> shutil.which("python")
          'C:\\Python33\\python.EXE'

     This is also applied when 'cmd' is a path that contains a directory
     component:

          >>> shutil.which("C:\\Python33\\python")
          'C:\\Python33\\python.EXE'

     Added in version 3.3.

     Changed in version 3.8: The *note bytes: 1c2. type is now accepted.
     If 'cmd' type is ‘bytes’, the result type is also ‘bytes’.

     Changed in version 3.12: On Windows, the current directory is no
     longer prepended to the search path if 'mode' includes ‘os.X_OK’
     and WinAPI ‘NeedCurrentDirectoryForExePathW(cmd)’ is false, else
     the current directory is prepended even if it is already in the
     search path; ‘PATHEXT’ is used now even when 'cmd' includes a
     directory component or ends with an extension that is in ‘PATHEXT’;
     and filenames that have no extension can now be found.

 -- Exception: shutil.Error

     This exception collects exceptions that are raised during a
     multi-file operation.  For *note copytree(): a36, the exception
     argument is a list of 3-tuples ('srcname', 'dstname', 'exception').

* Menu:

* Platform-dependent efficient copy operations::
* copytree example::
* rmtree example::


File: python.info,  Node: Platform-dependent efficient copy operations,  Next: copytree example,  Up: Directory and files operations

5.11.9.2 Platform-dependent efficient copy operations
.....................................................

Starting from Python 3.8, all functions involving a file copy (*note
copyfile(): a67, *note copy(): a68, *note copy2(): a69, *note
copytree(): a36, and *note move(): a6a.) may use platform-specific
“fast-copy” syscalls in order to copy the file more efficiently (see
bpo-33671(1)).  “fast-copy” means that the copying operation occurs
within the kernel, avoiding the use of userspace buffers in Python as in
“‘outfd.write(infd.read())’”.

On macOS fcopyfile(2) is used to copy the file content (not metadata).

On Linux *note os.sendfile(): b28. is used.

On Windows *note shutil.copyfile(): a67. uses a bigger default buffer
size (1 MiB instead of 64 KiB) and a *note memoryview(): 2eb.-based
variant of *note shutil.copyfileobj(): a6b. is used.

If the fast-copy operation fails and no data was written in the
destination file then shutil will silently fall back to less efficient
*note copyfileobj(): a6b. function internally.

Changed in version 3.8.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33671

   (2) http://www.manpagez.com/man/3/copyfile/


File: python.info,  Node: copytree example,  Next: rmtree example,  Prev: Platform-dependent efficient copy operations,  Up: Directory and files operations

5.11.9.3 copytree example
.........................

An example that uses the *note ignore_patterns(): 2a3c. helper:

     from shutil import copytree, ignore_patterns

     copytree(source, destination, ignore=ignore_patterns('*.pyc', 'tmp*'))

This will copy everything except ‘.pyc’ files and files or directories
whose name starts with ‘tmp’.

Another example that uses the 'ignore' argument to add a logging call:

     from shutil import copytree
     import logging

     def _logpath(path, names):
         logging.info('Working in %s', path)
         return []   # nothing will be ignored

     copytree(source, destination, ignore=_logpath)


File: python.info,  Node: rmtree example,  Prev: copytree example,  Up: Directory and files operations

5.11.9.4 rmtree example
.......................

This example shows how to remove a directory tree on Windows where some
of the files have their read-only bit set.  It uses the onexc callback
to clear the readonly bit and reattempt the remove.  Any subsequent
failure will propagate.

     import os, stat
     import shutil

     def remove_readonly(func, path, _):
         "Clear the readonly bit and reattempt the removal"
         os.chmod(path, stat.S_IWRITE)
         func(path)

     shutil.rmtree(directory, onexc=remove_readonly)


File: python.info,  Node: Archiving operations,  Next: Querying the size of the output terminal,  Prev: Directory and files operations,  Up: shutil — High-level file operations

5.11.9.5 Archiving operations
.............................

Added in version 3.2.

Changed in version 3.5: Added support for the 'xztar' format.

High-level utilities to create and read compressed and archived files
are also provided.  They rely on the *note zipfile: 131. and *note
tarfile: de. modules.

 -- Function: shutil.make_archive (base_name, format[, root_dir[,
          base_dir[, verbose[, dry_run[, owner[, group[, logger]]]]]]])

     Create an archive file (such as zip or tar) and return its name.

     'base_name' is the name of the file to create, including the path,
     minus any format-specific extension.

     'format' is the archive format: one of “zip” (if the *note zlib:
     133. module is available), “tar”, “gztar” (if the ‘zlib’ module is
     available), “bztar” (if the *note bz2: 13. module is available), or
     “xztar” (if the *note lzma: 8a. module is available).

     'root_dir' is a directory that will be the root directory of the
     archive, all paths in the archive will be relative to it; for
     example, we typically chdir into 'root_dir' before creating the
     archive.

     'base_dir' is the directory where we start archiving from; i.e.
     'base_dir' will be the common prefix of all files and directories
     in the archive.  'base_dir' must be given relative to 'root_dir'.
     See *note Archiving example with base_dir: 2a44. for how to use
     'base_dir' and 'root_dir' together.

     'root_dir' and 'base_dir' both default to the current directory.

     If 'dry_run' is true, no archive is created, but the operations
     that would be executed are logged to 'logger'.

     'owner' and 'group' are used when creating a tar archive.  By
     default, uses the current owner and group.

     'logger' must be an object compatible with PEP 282(1), usually an
     instance of *note logging.Logger: b6a.

     The 'verbose' argument is unused and deprecated.

     Raises an *note auditing event: 1a15. ‘shutil.make_archive’ with
     arguments ‘base_name’, ‘format’, ‘root_dir’, ‘base_dir’.

          Note: This function is not thread-safe when custom archivers
          registered with *note register_archive_format(): 2a45. do not
          support the 'root_dir' argument.  In this case it temporarily
          changes the current working directory of the process to
          'root_dir' to perform archiving.

     Changed in version 3.8: The modern pax (POSIX.1-2001) format is now
     used instead of the legacy GNU format for archives created with
     ‘format="tar"’.

     Changed in version 3.10.6: This function is now made thread-safe
     during creation of standard ‘.zip’ and tar archives.

 -- Function: shutil.get_archive_formats ()

     Return a list of supported formats for archiving.  Each element of
     the returned sequence is a tuple ‘(name, description)’.

     By default ‘shutil’ provides these formats:

        - 'zip': ZIP file (if the *note zlib: 133. module is available).

        - 'tar': Uncompressed tar file.  Uses POSIX.1-2001 pax format
          for new archives.

        - 'gztar': gzip’ed tar-file (if the *note zlib: 133. module is
          available).

        - 'bztar': bzip2’ed tar-file (if the *note bz2: 13. module is
          available).

        - 'xztar': xz’ed tar-file (if the *note lzma: 8a. module is
          available).

     You can register new formats or provide your own archiver for any
     existing formats, by using *note register_archive_format(): 2a45.

 -- Function: shutil.register_archive_format (name, function[,
          extra_args[, description]])

     Register an archiver for the format 'name'.

     'function' is the callable that will be used to unpack archives.
     The callable will receive the 'base_name' of the file to create,
     followed by the 'base_dir' (which defaults to *note os.curdir:
     29ac.) to start archiving from.  Further arguments are passed as
     keyword arguments: 'owner', 'group', 'dry_run' and 'logger' (as
     passed in *note make_archive(): 4b6.).

     If 'function' has the custom attribute ‘function.supports_root_dir’
     set to ‘True’, the 'root_dir' argument is passed as a keyword
     argument.  Otherwise the current working directory of the process
     is temporarily changed to 'root_dir' before calling 'function'.  In
     this case *note make_archive(): 4b6. is not thread-safe.

     If given, 'extra_args' is a sequence of ‘(name, value)’ pairs that
     will be used as extra keywords arguments when the archiver callable
     is used.

     'description' is used by *note get_archive_formats(): 2a46. which
     returns the list of archivers.  Defaults to an empty string.

     Changed in version 3.12: Added support for functions supporting the
     'root_dir' argument.

 -- Function: shutil.unregister_archive_format (name)

     Remove the archive format 'name' from the list of supported
     formats.

 -- Function: shutil.unpack_archive (filename[, extract_dir[, format[,
          filter]]])

     Unpack an archive.  'filename' is the full path of the archive.

     'extract_dir' is the name of the target directory where the archive
     is unpacked.  If not provided, the current working directory is
     used.

     'format' is the archive format: one of “zip”, “tar”, “gztar”,
     “bztar”, or “xztar”.  Or any other format registered with *note
     register_unpack_format(): 2a48.  If not provided,
     ‘unpack_archive()’ will use the archive file name extension and see
     if an unpacker was registered for that extension.  In case none is
     found, a *note ValueError: 202. is raised.

     The keyword-only 'filter' argument is passed to the underlying
     unpacking function.  For zip files, 'filter' is not accepted.  For
     tar files, it is recommended to set it to ‘'data'’, unless using
     features specific to tar and UNIX-like filesystems.  (See *note
     Extraction filters: 46f. for details.)  The ‘'data'’ filter will
     become the default for tar files in Python 3.14.

     Raises an *note auditing event: 1a15. ‘shutil.unpack_archive’ with
     arguments ‘filename’, ‘extract_dir’, ‘format’.

          Warning: Never extract archives from untrusted sources without
          prior inspection.  It is possible that files are created
          outside of the path specified in the 'extract_dir' argument,
          e.g.  members that have absolute filenames starting with “/”
          or filenames with two dots “..”.

     Changed in version 3.7: Accepts a *note path-like object: 2a0. for
     'filename' and 'extract_dir'.

     Changed in version 3.12: Added the 'filter' argument.

 -- Function: shutil.register_unpack_format (name, extensions,
          function[, extra_args[, description]])

     Registers an unpack format.  'name' is the name of the format and
     'extensions' is a list of extensions corresponding to the format,
     like ‘.zip’ for Zip files.

     'function' is the callable that will be used to unpack archives.
     The callable will receive:

        - the path of the archive, as a positional argument;

        - the directory the archive must be extracted to, as a
          positional argument;

        - possibly a 'filter' keyword argument, if it was given to *note
          unpack_archive(): 46e.;

        - additional keyword arguments, specified by 'extra_args' as a
          sequence of ‘(name, value)’ tuples.

     'description' can be provided to describe the format, and will be
     returned by the *note get_unpack_formats(): 2a49. function.

 -- Function: shutil.unregister_unpack_format (name)

     Unregister an unpack format.  'name' is the name of the format.

 -- Function: shutil.get_unpack_formats ()

     Return a list of all registered formats for unpacking.  Each
     element of the returned sequence is a tuple ‘(name, extensions,
     description)’.

     By default ‘shutil’ provides these formats:

        - 'zip': ZIP file (unpacking compressed files works only if the
          corresponding module is available).

        - 'tar': uncompressed tar file.

        - 'gztar': gzip’ed tar-file (if the *note zlib: 133. module is
          available).

        - 'bztar': bzip2’ed tar-file (if the *note bz2: 13. module is
          available).

        - 'xztar': xz’ed tar-file (if the *note lzma: 8a. module is
          available).

     You can register new formats or provide your own unpacker for any
     existing formats, by using *note register_unpack_format(): 2a48.

* Menu:

* Archiving example::
* Archiving example with base_dir::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0282/


File: python.info,  Node: Archiving example,  Next: Archiving example with base_dir,  Up: Archiving operations

5.11.9.6 Archiving example
..........................

In this example, we create a gzip’ed tar-file archive containing all
files found in the ‘.ssh’ directory of the user:

     >>> from shutil import make_archive
     >>> import os
     >>> archive_name = os.path.expanduser(os.path.join('~', 'myarchive'))
     >>> root_dir = os.path.expanduser(os.path.join('~', '.ssh'))
     >>> make_archive(archive_name, 'gztar', root_dir)
     '/Users/tarek/myarchive.tar.gz'

The resulting archive contains:

     $ tar -tzvf /Users/tarek/myarchive.tar.gz
     drwx------ tarek/staff       0 2010-02-01 16:23:40 ./
     -rw-r--r-- tarek/staff     609 2008-06-09 13:26:54 ./authorized_keys
     -rwxr-xr-x tarek/staff      65 2008-06-09 13:26:54 ./config
     -rwx------ tarek/staff     668 2008-06-09 13:26:54 ./id_dsa
     -rwxr-xr-x tarek/staff     609 2008-06-09 13:26:54 ./id_dsa.pub
     -rw------- tarek/staff    1675 2008-06-09 13:26:54 ./id_rsa
     -rw-r--r-- tarek/staff     397 2008-06-09 13:26:54 ./id_rsa.pub
     -rw-r--r-- tarek/staff   37192 2010-02-06 18:23:10 ./known_hosts


File: python.info,  Node: Archiving example with base_dir,  Prev: Archiving example,  Up: Archiving operations

5.11.9.7 Archiving example with 'base_dir'
..........................................

In this example, similar to the *note one above: 2a4c, we show how to
use *note make_archive(): 4b6, but this time with the usage of
'base_dir'.  We now have the following directory structure:

     $ tree tmp
     tmp
     └── root
         └── structure
             ├── content
                 └── please_add.txt
             └── do_not_add.txt

In the final archive, ‘please_add.txt’ should be included, but
‘do_not_add.txt’ should not.  Therefore we use the following:

     >>> from shutil import make_archive
     >>> import os
     >>> archive_name = os.path.expanduser(os.path.join('~', 'myarchive'))
     >>> make_archive(
     ...     archive_name,
     ...     'tar',
     ...     root_dir='tmp/root',
     ...     base_dir='structure/content',
     ... )
     '/Users/tarek/myarchive.tar'

Listing the files in the resulting archive gives us:

     $ python -m tarfile -l /Users/tarek/myarchive.tar
     structure/content/
     structure/content/please_add.txt


File: python.info,  Node: Querying the size of the output terminal,  Prev: Archiving operations,  Up: shutil — High-level file operations

5.11.9.8 Querying the size of the output terminal
.................................................

 -- Function: shutil.get_terminal_size (fallback=(columns, lines))

     Get the size of the terminal window.

     For each of the two dimensions, the environment variable, ‘COLUMNS’
     and ‘LINES’ respectively, is checked.  If the variable is defined
     and the value is a positive integer, it is used.

     When ‘COLUMNS’ or ‘LINES’ is not defined, which is the common case,
     the terminal connected to *note sys.__stdout__: 2a4f. is queried by
     invoking *note os.get_terminal_size(): 1146.

     If the terminal size cannot be successfully queried, either because
     the system doesn’t support querying, or because we are not
     connected to a terminal, the value given in ‘fallback’ parameter is
     used.  ‘fallback’ defaults to ‘(80, 24)’ which is the default size
     used by many terminal emulators.

     The value returned is a named tuple of type *note os.terminal_size:
     2a50.

     See also: The Single UNIX Specification, Version 2, Other
     Environment Variables(1).

     Added in version 3.3.

     Changed in version 3.11: The ‘fallback’ values are also used if
     *note os.get_terminal_size(): 1146. returns zeroes.

See also
........

Module *note os: a1.

     Operating system interfaces, including functions to work with files
     at a lower level than Python *note file objects: 1208.

Module *note io: 7f.

     Python’s built-in I/O library, including both abstract classes and
     some concrete classes such as file I/O.

Built-in function *note open(): 51f.

     The standard way to open files for reading and writing with Python.

   ---------- Footnotes ----------

   (1) 
https://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html#tag_002_003


File: python.info,  Node: Data Persistence,  Next: Data Compression and Archiving,  Prev: File and Directory Access,  Up: The Python Standard Library

5.12 Data Persistence
=====================

The modules described in this chapter support storing Python data in a
persistent form on disk.  The *note pickle: a6. and *note marshal: 8d.
modules can turn many Python data types into a stream of bytes and then
recreate the objects from the bytes.  The various DBM-related modules
support a family of hash-based file formats that store a mapping of
strings to other strings.

The list of modules described in this chapter is:

* Menu:

* pickle — Python object serialization::
* copyreg — Register pickle support functions::
* shelve — Python object persistence::
* marshal — Internal Python object serialization::
* dbm — Interfaces to Unix “databases”::
* sqlite3 — DB-API 2.0 interface for SQLite databases: sqlite3 — DB-API 2 0 interface for SQLite databases.


File: python.info,  Node: pickle — Python object serialization,  Next: copyreg — Register pickle support functions,  Up: Data Persistence

5.12.1 ‘pickle’ — Python object serialization
---------------------------------------------

'Source code:' Lib/pickle.py(1)

__________________________________________________________________

The ‘pickle’ module implements binary protocols for serializing and
de-serializing a Python object structure.  '“Pickling”' is the process
whereby a Python object hierarchy is converted into a byte stream, and
'“unpickling”' is the inverse operation, whereby a byte stream (from a
*note binary file: 1e26. or *note bytes-like object: d55.) is converted
back into an object hierarchy.  Pickling (and unpickling) is
alternatively known as “serialization”, “marshalling,” (2) or
“flattening”; however, to avoid confusion, the terms used here are
“pickling” and “unpickling”.

     Warning: The ‘pickle’ module 'is not secure'.  Only unpickle data
     you trust.

     It is possible to construct malicious pickle data which will
     'execute arbitrary code during unpickling'.  Never unpickle data
     that could have come from an untrusted source, or that could have
     been tampered with.

     Consider signing data with *note hmac: 6a. if you need to ensure
     that it has not been tampered with.

     Safer serialization formats such as *note json: 82. may be more
     appropriate if you are processing untrusted data.  See *note
     Comparison with json: 2a57.

* Menu:

* Relationship to other Python modules::
* Data stream format::
* Module Interface::
* What can be pickled and unpickled?::
* Pickling Class Instances::
* Custom Reduction for Types, Functions, and Other Objects: Custom Reduction for Types Functions and Other Objects.
* Out-of-band Buffers::
* Restricting Globals::
* Performance: Performance<2>.
* Examples: Examples<7>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pickle.py

   (2) Don’t confuse this with the *note marshal: 8d. module


File: python.info,  Node: Relationship to other Python modules,  Next: Data stream format,  Up: pickle — Python object serialization

5.12.1.1 Relationship to other Python modules
.............................................

* Menu:

* Comparison with marshal::
* Comparison with json::


File: python.info,  Node: Comparison with marshal,  Next: Comparison with json,  Up: Relationship to other Python modules

5.12.1.2 Comparison with ‘marshal’
..................................

Python has a more primitive serialization module called *note marshal:
8d, but in general ‘pickle’ should always be the preferred way to
serialize Python objects.  ‘marshal’ exists primarily to support
Python’s ‘.pyc’ files.

The ‘pickle’ module differs from *note marshal: 8d. in several
significant ways:

   * *note marshal: 8d. cannot be used to serialize user-defined classes
     and their instances.  ‘pickle’ can save and restore class instances
     transparently, however the class definition must be importable and
     live in the same module as when the object was stored.

   * The *note marshal: 8d. serialization format is not guaranteed to be
     portable across Python versions.  Because its primary job in life
     is to support ‘.pyc’ files, the Python implementers reserve the
     right to change the serialization format in non-backwards
     compatible ways should the need arise.  The ‘pickle’ serialization
     format is guaranteed to be backwards compatible across Python
     releases provided a compatible pickle protocol is chosen and
     pickling and unpickling code deals with Python 2 to Python 3 type
     differences if your data is crossing that unique breaking change
     language boundary.


File: python.info,  Node: Comparison with json,  Prev: Comparison with marshal,  Up: Relationship to other Python modules

5.12.1.3 Comparison with ‘json’
...............................

There are fundamental differences between the pickle protocols and JSON
(JavaScript Object Notation)(1):

   * JSON is a text serialization format (it outputs unicode text,
     although most of the time it is then encoded to ‘utf-8’), while
     pickle is a binary serialization format;

   * JSON is human-readable, while pickle is not;

   * JSON is interoperable and widely used outside of the Python
     ecosystem, while pickle is Python-specific;

   * JSON, by default, can only represent a subset of the Python
     built-in types, and no custom classes; pickle can represent an
     extremely large number of Python types (many of them automatically,
     by clever usage of Python’s introspection facilities; complex cases
     can be tackled by implementing *note specific object APIs: 2a5b.);

   * Unlike pickle, deserializing untrusted JSON does not in itself
     create an arbitrary code execution vulnerability.

See also
........

The *note json: 82. module: a standard library module allowing JSON
serialization and deserialization.

   ---------- Footnotes ----------

   (1) https://json.org


File: python.info,  Node: Data stream format,  Next: Module Interface,  Prev: Relationship to other Python modules,  Up: pickle — Python object serialization

5.12.1.4 Data stream format
...........................

The data format used by ‘pickle’ is Python-specific.  This has the
advantage that there are no restrictions imposed by external standards
such as JSON (which can’t represent pointer sharing); however it means
that non-Python programs may not be able to reconstruct pickled Python
objects.

By default, the ‘pickle’ data format uses a relatively compact binary
representation.  If you need optimal size characteristics, you can
efficiently *note compress: 2a5d. pickled data.

The module *note pickletools: a7. contains tools for analyzing data
streams generated by ‘pickle’.  ‘pickletools’ source code has extensive
comments about opcodes used by pickle protocols.

There are currently 6 different protocols which can be used for
pickling.  The higher the protocol used, the more recent the version of
Python needed to read the pickle produced.

   * Protocol version 0 is the original “human-readable” protocol and is
     backwards compatible with earlier versions of Python.

   * Protocol version 1 is an old binary format which is also compatible
     with earlier versions of Python.

   * Protocol version 2 was introduced in Python 2.3.  It provides much
     more efficient pickling of *note new-style classes: 2a5e.  Refer to
     PEP 307(1) for information about improvements brought by protocol
     2.

   * Protocol version 3 was added in Python 3.0.  It has explicit
     support for *note bytes: 1c2. objects and cannot be unpickled by
     Python 2.x.  This was the default protocol in Python 3.0–3.7.

   * Protocol version 4 was added in Python 3.4.  It adds support for
     very large objects, pickling more kinds of objects, and some data
     format optimizations.  It is the default protocol starting with
     Python 3.8.  Refer to PEP 3154(2) for information about
     improvements brought by protocol 4.

   * Protocol version 5 was added in Python 3.8.  It adds support for
     out-of-band data and speedup for in-band data.  Refer to PEP 574(3)
     for information about improvements brought by protocol 5.

     Note: Serialization is a more primitive notion than persistence;
     although ‘pickle’ reads and writes file objects, it does not handle
     the issue of naming persistent objects, nor the (even more
     complicated) issue of concurrent access to persistent objects.  The
     ‘pickle’ module can transform a complex object into a byte stream
     and it can transform the byte stream into an object with the same
     internal structure.  Perhaps the most obvious thing to do with
     these byte streams is to write them onto a file, but it is also
     conceivable to send them across a network or store them in a
     database.  The *note shelve: c3. module provides a simple interface
     to pickle and unpickle objects on DBM-style database files.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0307/

   (2) https://peps.python.org/pep-3154/

   (3) https://peps.python.org/pep-0574/


File: python.info,  Node: Module Interface,  Next: What can be pickled and unpickled?,  Prev: Data stream format,  Up: pickle — Python object serialization

5.12.1.5 Module Interface
.........................

To serialize an object hierarchy, you simply call the *note dumps():
14f3. function.  Similarly, to de-serialize a data stream, you call the
*note loads(): d39. function.  However, if you want more control over
serialization and de-serialization, you can create a *note Pickler: a2b.
or an *note Unpickler: 15c4. object, respectively.

The ‘pickle’ module provides the following constants:

 -- Data: pickle.HIGHEST_PROTOCOL

     An integer, the highest *note protocol version: ce7. available.
     This value can be passed as a 'protocol' value to functions *note
     dump(): 2a60. and *note dumps(): 14f3. as well as the *note
     Pickler: a2b. constructor.

 -- Data: pickle.DEFAULT_PROTOCOL

     An integer, the default *note protocol version: ce7. used for
     pickling.  May be less than *note HIGHEST_PROTOCOL: 14f4.
     Currently the default protocol is 4, first introduced in Python 3.4
     and incompatible with previous versions.

     Changed in version 3.0: The default protocol is 3.

     Changed in version 3.8: The default protocol is 4.

The ‘pickle’ module provides the following functions to make the
pickling process more convenient:

 -- Function: pickle.dump (obj, file, protocol=None, *,
          fix_imports=True, buffer_callback=None)

     Write the pickled representation of the object 'obj' to the open
     *note file object: 1208. 'file'.  This is equivalent to
     ‘Pickler(file, protocol).dump(obj)’.

     Arguments 'file', 'protocol', 'fix_imports' and 'buffer_callback'
     have the same meaning as in the *note Pickler: a2b. constructor.

     Changed in version 3.8: The 'buffer_callback' argument was added.

 -- Function: pickle.dumps (obj, protocol=None, *, fix_imports=True,
          buffer_callback=None)

     Return the pickled representation of the object 'obj' as a *note
     bytes: 1c2. object, instead of writing it to a file.

     Arguments 'protocol', 'fix_imports' and 'buffer_callback' have the
     same meaning as in the *note Pickler: a2b. constructor.

     Changed in version 3.8: The 'buffer_callback' argument was added.

 -- Function: pickle.load (file, *, fix_imports=True, encoding='ASCII',
          errors='strict', buffers=None)

     Read the pickled representation of an object from the open *note
     file object: 1208. 'file' and return the reconstituted object
     hierarchy specified therein.  This is equivalent to
     ‘Unpickler(file).load()’.

     The protocol version of the pickle is detected automatically, so no
     protocol argument is needed.  Bytes past the pickled representation
     of the object are ignored.

     Arguments 'file', 'fix_imports', 'encoding', 'errors', 'strict' and
     'buffers' have the same meaning as in the *note Unpickler: 15c4.
     constructor.

     Changed in version 3.8: The 'buffers' argument was added.

 -- Function: pickle.loads (data, /, *, fix_imports=True,
          encoding='ASCII', errors='strict', buffers=None)

     Return the reconstituted object hierarchy of the pickled
     representation 'data' of an object.  'data' must be a *note
     bytes-like object: d55.

     The protocol version of the pickle is detected automatically, so no
     protocol argument is needed.  Bytes past the pickled representation
     of the object are ignored.

     Arguments 'fix_imports', 'encoding', 'errors', 'strict' and
     'buffers' have the same meaning as in the *note Unpickler: 15c4.
     constructor.

     Changed in version 3.8: The 'buffers' argument was added.

The ‘pickle’ module defines three exceptions:

 -- Exception: pickle.PickleError

     Common base class for the other pickling exceptions.  It inherits
     from *note Exception: 9e5.

 -- Exception: pickle.PicklingError

     Error raised when an unpicklable object is encountered by *note
     Pickler: a2b.  It inherits from *note PickleError: 2a61.

     Refer to *note What can be pickled and unpickled?: 2a63. to learn
     what kinds of objects can be pickled.

 -- Exception: pickle.UnpicklingError

     Error raised when there is a problem unpickling an object, such as
     a data corruption or a security violation.  It inherits from *note
     PickleError: 2a61.

     Note that other exceptions may also be raised during unpickling,
     including (but not necessarily limited to) AttributeError,
     EOFError, ImportError, and IndexError.

The ‘pickle’ module exports three classes, *note Pickler: a2b, *note
Unpickler: 15c4. and *note PickleBuffer: 15c6.:

 -- Class: pickle.Pickler (file, protocol=None, *, fix_imports=True,
          buffer_callback=None)

     This takes a binary file for writing a pickle data stream.

     The optional 'protocol' argument, an integer, tells the pickler to
     use the given protocol; supported protocols are 0 to *note
     HIGHEST_PROTOCOL: 14f4.  If not specified, the default is *note
     DEFAULT_PROTOCOL: 834.  If a negative number is specified,
     ‘HIGHEST_PROTOCOL’ is selected.

     The 'file' argument must have a write() method that accepts a
     single bytes argument.  It can thus be an on-disk file opened for
     binary writing, an *note io.BytesIO: ed8. instance, or any other
     custom object that meets this interface.

     If 'fix_imports' is true and 'protocol' is less than 3, pickle will
     try to map the new Python 3 names to the old module names used in
     Python 2, so that the pickle data stream is readable with Python 2.

     If 'buffer_callback' is ‘None’ (the default), buffer views are
     serialized into 'file' as part of the pickle stream.

     If 'buffer_callback' is not ‘None’, then it can be called any
     number of times with a buffer view.  If the callback returns a
     false value (such as ‘None’), the given buffer is *note
     out-of-band: 2a65.; otherwise the buffer is serialized in-band,
     i.e.  inside the pickle stream.

     It is an error if 'buffer_callback' is not ‘None’ and 'protocol' is
     ‘None’ or smaller than 5.

     Changed in version 3.8: The 'buffer_callback' argument was added.

      -- Method: dump (obj)

          Write the pickled representation of 'obj' to the open file
          object given in the constructor.

      -- Method: persistent_id (obj)

          Do nothing by default.  This exists so a subclass can override
          it.

          If ‘persistent_id()’ returns ‘None’, 'obj' is pickled as
          usual.  Any other value causes ‘Pickler’ to emit the returned
          value as a persistent ID for 'obj'.  The meaning of this
          persistent ID should be defined by *note
          Unpickler.persistent_load(): 16ac.  Note that the value
          returned by ‘persistent_id()’ cannot itself have a persistent
          ID.

          See *note Persistence of External Objects: 2a66. for details
          and examples of uses.

          Changed in version 3.13: Add the default implementation of
          this method in the C implementation of ‘Pickler’.

      -- Attribute: dispatch_table

          A pickler object’s dispatch table is a registry of 'reduction
          functions' of the kind which can be declared using *note
          copyreg.pickle(): 2a67.  It is a mapping whose keys are
          classes and whose values are reduction functions.  A reduction
          function takes a single argument of the associated class and
          should conform to the same interface as a *note __reduce__():
          9de. method.

          By default, a pickler object will not have a *note
          dispatch_table: 1166. attribute, and it will instead use the
          global dispatch table managed by the *note copyreg: 26.
          module.  However, to customize the pickling for a specific
          pickler object one can set the ‘dispatch_table’ attribute to a
          dict-like object.  Alternatively, if a subclass of ‘Pickler’
          has a ‘dispatch_table’ attribute then this will be used as the
          default dispatch table for instances of that class.

          See *note Dispatch Tables: 2a68. for usage examples.

          Added in version 3.3.

      -- Method: reducer_override (obj)

          Special reducer that can be defined in ‘Pickler’ subclasses.
          This method has priority over any reducer in the *note
          dispatch_table: 1166.  It should conform to the same interface
          as a *note __reduce__(): 9de. method, and can optionally
          return *note NotImplemented: 7d6. to fallback on
          ‘dispatch_table’-registered reducers to pickle ‘obj’.

          For a detailed example, see *note Custom Reduction for Types,
          Functions, and Other Objects: 2a69.

          Added in version 3.8.

      -- Attribute: fast

          Deprecated.  Enable fast mode if set to a true value.  The
          fast mode disables the usage of memo, therefore speeding the
          pickling process by not generating superfluous PUT opcodes.
          It should not be used with self-referential objects, doing
          otherwise will cause ‘Pickler’ to recurse infinitely.

          Use *note pickletools.optimize(): 2a6b. if you need more
          compact pickles.

 -- Class: pickle.Unpickler (file, *, fix_imports=True,
          encoding='ASCII', errors='strict', buffers=None)

     This takes a binary file for reading a pickle data stream.

     The protocol version of the pickle is detected automatically, so no
     protocol argument is needed.

     The argument 'file' must have three methods, a read() method that
     takes an integer argument, a readinto() method that takes a buffer
     argument and a readline() method that requires no arguments, as in
     the *note io.BufferedIOBase: 697. interface.  Thus 'file' can be an
     on-disk file opened for binary reading, an *note io.BytesIO: ed8.
     object, or any other custom object that meets this interface.

     The optional arguments 'fix_imports', 'encoding' and 'errors' are
     used to control compatibility support for pickle stream generated
     by Python 2.  If 'fix_imports' is true, pickle will try to map the
     old Python 2 names to the new names used in Python 3.  The
     'encoding' and 'errors' tell pickle how to decode 8-bit string
     instances pickled by Python 2; these default to ‘ASCII’ and
     ‘strict’, respectively.  The 'encoding' can be ‘bytes’ to read
     these 8-bit string instances as bytes objects.  Using
     ‘encoding='latin1'’ is required for unpickling NumPy arrays and
     instances of *note datetime: 1cc, *note date: 1cd. and *note time:
     1ce. pickled by Python 2.

     If 'buffers' is ‘None’ (the default), then all data necessary for
     deserialization must be contained in the pickle stream.  This means
     that the 'buffer_callback' argument was ‘None’ when a *note
     Pickler: a2b. was instantiated (or when *note dump(): 2a60. or
     *note dumps(): 14f3. was called).

     If 'buffers' is not ‘None’, it should be an iterable of
     buffer-enabled objects that is consumed each time the pickle stream
     references an *note out-of-band: 2a65. buffer view.  Such buffers
     have been given in order to the 'buffer_callback' of a Pickler
     object.

     Changed in version 3.8: The 'buffers' argument was added.

      -- Method: load ()

          Read the pickled representation of an object from the open
          file object given in the constructor, and return the
          reconstituted object hierarchy specified therein.  Bytes past
          the pickled representation of the object are ignored.

      -- Method: persistent_load (pid)

          Raise an *note UnpicklingError: 2a64. by default.

          If defined, ‘persistent_load()’ should return the object
          specified by the persistent ID 'pid'.  If an invalid
          persistent ID is encountered, an *note UnpicklingError: 2a64.
          should be raised.

          See *note Persistence of External Objects: 2a66. for details
          and examples of uses.

          Changed in version 3.13: Add the default implementation of
          this method in the C implementation of ‘Unpickler’.

      -- Method: find_class (module, name)

          Import 'module' if necessary and return the object called
          'name' from it, where the 'module' and 'name' arguments are
          *note str: 44f. objects.  Note, unlike its name suggests,
          ‘find_class()’ is also used for finding functions.

          Subclasses may override this to gain control over what type of
          objects and how they can be loaded, potentially reducing
          security risks.  Refer to *note Restricting Globals: 2a6e. for
          details.

          Raises an *note auditing event: 1a15. ‘pickle.find_class’ with
          arguments ‘module’, ‘name’.

 -- Class: pickle.PickleBuffer (buffer)

     A wrapper for a buffer representing picklable data.  'buffer' must
     be a *note buffer-providing: 2e8. object, such as a *note
     bytes-like object: d55. or a N-dimensional array.

     ‘PickleBuffer’ is itself a buffer provider, therefore it is
     possible to pass it to other APIs expecting a buffer-providing
     object, such as *note memoryview: 2eb.

     ‘PickleBuffer’ objects can only be serialized using pickle protocol
     5 or higher.  They are eligible for *note out-of-band
     serialization: 2a65.

     Added in version 3.8.

      -- Method: raw ()

          Return a *note memoryview: 2eb. of the memory area underlying
          this buffer.  The returned object is a one-dimensional,
          C-contiguous memoryview with format ‘B’ (unsigned bytes).
          *note BufferError: 15e3. is raised if the buffer is neither C-
          nor Fortran-contiguous.

      -- Method: release ()

          Release the underlying buffer exposed by the PickleBuffer
          object.


File: python.info,  Node: What can be pickled and unpickled?,  Next: Pickling Class Instances,  Prev: Module Interface,  Up: pickle — Python object serialization

5.12.1.6 What can be pickled and unpickled?
...........................................

The following types can be pickled:

   * built-in constants (‘None’, ‘True’, ‘False’, ‘Ellipsis’, and *note
     NotImplemented: 7d6.);

   * integers, floating-point numbers, complex numbers;

   * strings, bytes, bytearrays;

   * tuples, lists, sets, and dictionaries containing only picklable
     objects;

   * functions (built-in and user-defined) accessible from the top level
     of a module (using *note def: 14a9, not *note lambda: 12e4.);

   * classes accessible from the top level of a module;

   * instances of such classes for which the result of calling *note
     __getstate__(): 5db. is picklable (see section *note Pickling Class
     Instances: 2a5b. for details).

Attempts to pickle unpicklable objects will raise the *note
PicklingError: 2a62. exception; when this happens, an unspecified number
of bytes may have already been written to the underlying file.  Trying
to pickle a highly recursive data structure may exceed the maximum
recursion depth, a *note RecursionError: d96. will be raised in this
case.  You can carefully raise this limit with *note
sys.setrecursionlimit(): 4c6.

Note that functions (built-in and user-defined) are pickled by fully
*note qualified name: 1acb, not by value.  (1)  This means that only the
function name is pickled, along with the name of the containing module
and classes.  Neither the function’s code, nor any of its function
attributes are pickled.  Thus the defining module must be importable in
the unpickling environment, and the module must contain the named
object, otherwise an exception will be raised.  (2)

Similarly, classes are pickled by fully qualified name, so the same
restrictions in the unpickling environment apply.  Note that none of the
class’s code or data is pickled, so in the following example the class
attribute ‘attr’ is not restored in the unpickling environment:

     class Foo:
         attr = 'A class attribute'

     picklestring = pickle.dumps(Foo)

These restrictions are why picklable functions and classes must be
defined at the top level of a module.

Similarly, when class instances are pickled, their class’s code and data
are not pickled along with them.  Only the instance data are pickled.
This is done on purpose, so you can fix bugs in a class or add methods
to the class and still load objects that were created with an earlier
version of the class.  If you plan to have long-lived objects that will
see many versions of a class, it may be worthwhile to put a version
number in the objects so that suitable conversions can be made by the
class’s *note __setstate__(): 9df. method.

   ---------- Footnotes ----------

   (1) This is why *note lambda: 12e4. functions cannot be pickled: all
‘lambda’ functions share the same name: ‘<lambda>’.

   (2) The exception raised will likely be an *note ImportError: 41c. or
an *note AttributeError: 34e. but it could be something else.


File: python.info,  Node: Pickling Class Instances,  Next: Custom Reduction for Types Functions and Other Objects,  Prev: What can be pickled and unpickled?,  Up: pickle — Python object serialization

5.12.1.7 Pickling Class Instances
.................................

In this section, we describe the general mechanisms available to you to
define, customize, and control how class instances are pickled and
unpickled.

In most cases, no additional code is needed to make instances picklable.
By default, pickle will retrieve the class and the attributes of an
instance via introspection.  When a class instance is unpickled, its
*note __init__(): 6b3. method is usually 'not' invoked.  The default
behaviour first creates an uninitialized instance and then restores the
saved attributes.  The following code shows an implementation of this
behaviour:

     def save(obj):
         return (obj.__class__, obj.__dict__)

     def restore(cls, attributes):
         obj = cls.__new__(cls)
         obj.__dict__.update(attributes)
         return obj

Classes can alter the default behaviour by providing one or several
special methods:

 -- Method: object.__getnewargs_ex__ ()

     In protocols 2 and newer, classes that implement the
     ‘__getnewargs_ex__()’ method can dictate the values passed to the
     *note __new__(): 583. method upon unpickling.  The method must
     return a pair ‘(args, kwargs)’ where 'args' is a tuple of
     positional arguments and 'kwargs' a dictionary of named arguments
     for constructing the object.  Those will be passed to the
     ‘__new__()’ method upon unpickling.

     You should implement this method if the *note __new__(): 583.
     method of your class requires keyword-only arguments.  Otherwise,
     it is recommended for compatibility to implement *note
     __getnewargs__(): e04.

     Changed in version 3.6: ‘__getnewargs_ex__()’ is now used in
     protocols 2 and 3.

 -- Method: object.__getnewargs__ ()

     This method serves a similar purpose as *note __getnewargs_ex__():
     2a73, but supports only positional arguments.  It must return a
     tuple of arguments ‘args’ which will be passed to the *note
     __new__(): 583. method upon unpickling.

     ‘__getnewargs__()’ will not be called if *note __getnewargs_ex__():
     2a73. is defined.

     Changed in version 3.6: Before Python 3.6, ‘__getnewargs__()’ was
     called instead of *note __getnewargs_ex__(): 2a73. in protocols 2
     and 3.

 -- Method: object.__getstate__ ()

     Classes can further influence how their instances are pickled by
     overriding the method ‘__getstate__()’.  It is called and the
     returned object is pickled as the contents for the instance,
     instead of a default state.  There are several cases:

        * For a class that has no instance *note __dict__: 55e. and no
          *note __slots__: 153a, the default state is ‘None’.

        * For a class that has an instance *note __dict__: 55e. and no
          *note __slots__: 153a, the default state is ‘self.__dict__’.

        * For a class that has an instance *note __dict__: 55e. and
          *note __slots__: 153a, the default state is a tuple consisting
          of two dictionaries: ‘self.__dict__’, and a dictionary mapping
          slot names to slot values.  Only slots that have a value are
          included in the latter.

        * For a class that has *note __slots__: 153a. and no instance
          *note __dict__: 55e, the default state is a tuple whose first
          item is ‘None’ and whose second item is a dictionary mapping
          slot names to slot values described in the previous bullet.

     Changed in version 3.11: Added the default implementation of the
     ‘__getstate__()’ method in the *note object: a9b. class.

 -- Method: object.__setstate__ (state)

     Upon unpickling, if the class defines ‘__setstate__()’, it is
     called with the unpickled state.  In that case, there is no
     requirement for the state object to be a dictionary.  Otherwise,
     the pickled state must be a dictionary and its items are assigned
     to the new instance’s dictionary.

          Note: If *note __reduce__(): 9de. returns a state with value
          ‘None’ at pickling, the ‘__setstate__()’ method will not be
          called upon unpickling.

Refer to the section *note Handling Stateful Objects: 2a74. for more
information about how to use the methods *note __getstate__(): 5db. and
*note __setstate__(): 9df.

     Note: At unpickling time, some methods like *note __getattr__():
     4d6, *note __getattribute__(): bf1, or *note __setattr__(): 20de.
     may be called upon the instance.  In case those methods rely on
     some internal invariant being true, the type should implement *note
     __new__(): 583. to establish such an invariant, as *note
     __init__(): 6b3. is not called when unpickling an instance.

As we shall see, pickle does not use directly the methods described
above.  In fact, these methods are part of the copy protocol which
implements the *note __reduce__(): 9de. special method.  The copy
protocol provides a unified interface for retrieving the data necessary
for pickling and copying objects.  (1)

Although powerful, implementing *note __reduce__(): 9de. directly in
your classes is error prone.  For this reason, class designers should
use the high-level interface (i.e., *note __getnewargs_ex__(): 2a73,
*note __getstate__(): 5db. and *note __setstate__(): 9df.) whenever
possible.  We will show, however, cases where using ‘__reduce__()’ is
the only option or leads to more efficient pickling or both.

 -- Method: object.__reduce__ ()

     The interface is currently defined as follows.  The ‘__reduce__()’
     method takes no argument and shall return either a string or
     preferably a tuple (the returned object is often referred to as the
     “reduce value”).

     If a string is returned, the string should be interpreted as the
     name of a global variable.  It should be the object’s local name
     relative to its module; the pickle module searches the module
     namespace to determine the object’s module.  This behaviour is
     typically useful for singletons.

     When a tuple is returned, it must be between two and six items
     long.  Optional items can either be omitted, or ‘None’ can be
     provided as their value.  The semantics of each item are in order:

        * A callable object that will be called to create the initial
          version of the object.

        * A tuple of arguments for the callable object.  An empty tuple
          must be given if the callable does not accept any argument.

        * Optionally, the object’s state, which will be passed to the
          object’s *note __setstate__(): 9df. method as previously
          described.  If the object has no such method then, the value
          must be a dictionary and it will be added to the object’s
          *note __dict__: 55e. attribute.

        * Optionally, an iterator (and not a sequence) yielding
          successive items.  These items will be appended to the object
          either using ‘obj.append(item)’ or, in batch, using
          ‘obj.extend(list_of_items)’.  This is primarily used for list
          subclasses, but may be used by other classes as long as they
          have *note append(): 213c. and *note extend(): 213f. methods
          with the appropriate signature.  (Whether ‘append()’ or
          ‘extend()’ is used depends on which pickle protocol version is
          used as well as the number of items to append, so both must be
          supported.)

        * Optionally, an iterator (not a sequence) yielding successive
          key-value pairs.  These items will be stored to the object
          using ‘obj[key] = value’.  This is primarily used for
          dictionary subclasses, but may be used by other classes as
          long as they implement *note __setitem__(): 1313.

        * Optionally, a callable with a ‘(obj, state)’ signature.  This
          callable allows the user to programmatically control the
          state-updating behavior of a specific object, instead of using
          ‘obj’’s static *note __setstate__(): 9df. method.  If not
          ‘None’, this callable will have priority over ‘obj’’s
          ‘__setstate__()’.

          Added in version 3.8: The optional sixth tuple item, ‘(obj,
          state)’, was added.

 -- Method: object.__reduce_ex__ (protocol)

     Alternatively, a ‘__reduce_ex__()’ method may be defined.  The only
     difference is this method should take a single integer argument,
     the protocol version.  When defined, pickle will prefer it over the
     *note __reduce__(): 9de. method.  In addition, ‘__reduce__()’
     automatically becomes a synonym for the extended version.  The main
     use for this method is to provide backwards-compatible reduce
     values for older Python releases.

* Menu:

* Persistence of External Objects::
* Dispatch Tables::
* Handling Stateful Objects::

   ---------- Footnotes ----------

   (1) The *note copy: 25. module uses this protocol for shallow and
deep copying operations.


File: python.info,  Node: Persistence of External Objects,  Next: Dispatch Tables,  Up: Pickling Class Instances

5.12.1.8 Persistence of External Objects
........................................

For the benefit of object persistence, the ‘pickle’ module supports the
notion of a reference to an object outside the pickled data stream.
Such objects are referenced by a persistent ID, which should be either a
string of alphanumeric characters (for protocol 0) (1) or just an
arbitrary object (for any newer protocol).

The resolution of such persistent IDs is not defined by the ‘pickle’
module; it will delegate this resolution to the user-defined methods on
the pickler and unpickler, *note persistent_id(): 16a5. and *note
persistent_load(): 16ac. respectively.

To pickle objects that have an external persistent ID, the pickler must
have a custom *note persistent_id(): 16a5. method that takes an object
as an argument and returns either ‘None’ or the persistent ID for that
object.  When ‘None’ is returned, the pickler simply pickles the object
as normal.  When a persistent ID string is returned, the pickler will
pickle that object, along with a marker so that the unpickler will
recognize it as a persistent ID.

To unpickle external objects, the unpickler must have a custom *note
persistent_load(): 16ac. method that takes a persistent ID object and
returns the referenced object.

Here is a comprehensive example presenting how persistent ID can be used
to pickle external objects by reference.

     # Simple example presenting how persistent ID can be used to pickle
     # external objects by reference.

     import pickle
     import sqlite3
     from collections import namedtuple

     # Simple class representing a record in our database.
     MemoRecord = namedtuple("MemoRecord", "key, task")

     class DBPickler(pickle.Pickler):

         def persistent_id(self, obj):
             # Instead of pickling MemoRecord as a regular class instance, we emit a
             # persistent ID.
             if isinstance(obj, MemoRecord):
                 # Here, our persistent ID is simply a tuple, containing a tag and a
                 # key, which refers to a specific record in the database.
                 return ("MemoRecord", obj.key)
             else:
                 # If obj does not have a persistent ID, return None. This means obj
                 # needs to be pickled as usual.
                 return None


     class DBUnpickler(pickle.Unpickler):

         def __init__(self, file, connection):
             super().__init__(file)
             self.connection = connection

         def persistent_load(self, pid):
             # This method is invoked whenever a persistent ID is encountered.
             # Here, pid is the tuple returned by DBPickler.
             cursor = self.connection.cursor()
             type_tag, key_id = pid
             if type_tag == "MemoRecord":
                 # Fetch the referenced record from the database and return it.
                 cursor.execute("SELECT * FROM memos WHERE key=?", (str(key_id),))
                 key, task = cursor.fetchone()
                 return MemoRecord(key, task)
             else:
                 # Always raises an error if you cannot return the correct object.
                 # Otherwise, the unpickler will think None is the object referenced
                 # by the persistent ID.
                 raise pickle.UnpicklingError("unsupported persistent object")


     def main():
         import io
         import pprint

         # Initialize and populate our database.
         conn = sqlite3.connect(":memory:")
         cursor = conn.cursor()
         cursor.execute("CREATE TABLE memos(key INTEGER PRIMARY KEY, task TEXT)")
         tasks = (
             'give food to fish',
             'prepare group meeting',
             'fight with a zebra',
             )
         for task in tasks:
             cursor.execute("INSERT INTO memos VALUES(NULL, ?)", (task,))

         # Fetch the records to be pickled.
         cursor.execute("SELECT * FROM memos")
         memos = [MemoRecord(key, task) for key, task in cursor]
         # Save the records using our custom DBPickler.
         file = io.BytesIO()
         DBPickler(file).dump(memos)

         print("Pickled records:")
         pprint.pprint(memos)

         # Update a record, just for good measure.
         cursor.execute("UPDATE memos SET task='learn italian' WHERE key=1")

         # Load the records from the pickle data stream.
         file.seek(0)
         memos = DBUnpickler(file, conn).load()

         print("Unpickled records:")
         pprint.pprint(memos)


     if __name__ == '__main__':
         main()

   ---------- Footnotes ----------

   (1) The limitation on alphanumeric characters is due to the fact that
persistent IDs in protocol 0 are delimited by the newline character.
Therefore if any kind of newline characters occurs in persistent IDs,
the resulting pickled data will become unreadable.


File: python.info,  Node: Dispatch Tables,  Next: Handling Stateful Objects,  Prev: Persistence of External Objects,  Up: Pickling Class Instances

5.12.1.9 Dispatch Tables
........................

If one wants to customize pickling of some classes without disturbing
any other code which depends on pickling, then one can create a pickler
with a private dispatch table.

The global dispatch table managed by the *note copyreg: 26. module is
available as ‘copyreg.dispatch_table’.  Therefore, one may choose to use
a modified copy of ‘copyreg.dispatch_table’ as a private dispatch table.

For example

     f = io.BytesIO()
     p = pickle.Pickler(f)
     p.dispatch_table = copyreg.dispatch_table.copy()
     p.dispatch_table[SomeClass] = reduce_SomeClass

creates an instance of *note pickle.Pickler: a2b. with a private
dispatch table which handles the ‘SomeClass’ class specially.
Alternatively, the code

     class MyPickler(pickle.Pickler):
         dispatch_table = copyreg.dispatch_table.copy()
         dispatch_table[SomeClass] = reduce_SomeClass
     f = io.BytesIO()
     p = MyPickler(f)

does the same but all instances of ‘MyPickler’ will by default share the
private dispatch table.  On the other hand, the code

     copyreg.pickle(SomeClass, reduce_SomeClass)
     f = io.BytesIO()
     p = pickle.Pickler(f)

modifies the global dispatch table shared by all users of the *note
copyreg: 26. module.


File: python.info,  Node: Handling Stateful Objects,  Prev: Dispatch Tables,  Up: Pickling Class Instances

5.12.1.10 Handling Stateful Objects
...................................

Here’s an example that shows how to modify pickling behavior for a
class.  The ‘TextReader’ class below opens a text file, and returns the
line number and line contents each time its ‘readline()’ method is
called.  If a ‘TextReader’ instance is pickled, all attributes 'except'
the file object member are saved.  When the instance is unpickled, the
file is reopened, and reading resumes from the last location.  The
‘__setstate__()’ and ‘__getstate__()’ methods are used to implement this
behavior.

     class TextReader:
         """Print and number lines in a text file."""

         def __init__(self, filename):
             self.filename = filename
             self.file = open(filename)
             self.lineno = 0

         def readline(self):
             self.lineno += 1
             line = self.file.readline()
             if not line:
                 return None
             if line.endswith('\n'):
                 line = line[:-1]
             return "%i: %s" % (self.lineno, line)

         def __getstate__(self):
             # Copy the object's state from self.__dict__ which contains
             # all our instance attributes. Always use the dict.copy()
             # method to avoid modifying the original state.
             state = self.__dict__.copy()
             # Remove the unpicklable entries.
             del state['file']
             return state

         def __setstate__(self, state):
             # Restore instance attributes (i.e., filename and lineno).
             self.__dict__.update(state)
             # Restore the previously opened file's state. To do so, we need to
             # reopen it and read from it until the line count is restored.
             file = open(self.filename)
             for _ in range(self.lineno):
                 file.readline()
             # Finally, save the file.
             self.file = file

A sample usage might be something like this:

     >>> reader = TextReader("hello.txt")
     >>> reader.readline()
     '1: Hello world!'
     >>> reader.readline()
     '2: I am line number two.'
     >>> new_reader = pickle.loads(pickle.dumps(reader))
     >>> new_reader.readline()
     '3: Goodbye!'


File: python.info,  Node: Custom Reduction for Types Functions and Other Objects,  Next: Out-of-band Buffers,  Prev: Pickling Class Instances,  Up: pickle — Python object serialization

5.12.1.11 Custom Reduction for Types, Functions, and Other Objects
..................................................................

Added in version 3.8.

Sometimes, *note dispatch_table: 1166. may not be flexible enough.  In
particular we may want to customize pickling based on another criterion
than the object’s type, or we may want to customize the pickling of
functions and classes.

For those cases, it is possible to subclass from the *note Pickler: a2b.
class and implement a *note reducer_override(): a2c. method.  This
method can return an arbitrary reduction tuple (see *note __reduce__():
9de.).  It can alternatively return *note NotImplemented: 7d6. to
fallback to the traditional behavior.

If both the *note dispatch_table: 1166. and *note reducer_override():
a2c. are defined, then ‘reducer_override()’ method takes priority.

     Note: For performance reasons, *note reducer_override(): a2c. may
     not be called for the following objects: ‘None’, ‘True’, ‘False’,
     and exact instances of *note int: 257, *note float: 2f7, *note
     bytes: 1c2, *note str: 44f, *note dict: 256, *note set: 5dc, *note
     frozenset: 5dd, *note list: 614. and *note tuple: 373.

Here is a simple example where we allow pickling and reconstructing a
given class:

     import io
     import pickle

     class MyClass:
         my_attribute = 1

     class MyPickler(pickle.Pickler):
         def reducer_override(self, obj):
             """Custom reducer for MyClass."""
             if getattr(obj, "__name__", None) == "MyClass":
                 return type, (obj.__name__, obj.__bases__,
                               {'my_attribute': obj.my_attribute})
             else:
                 # For any other object, fallback to usual reduction
                 return NotImplemented

     f = io.BytesIO()
     p = MyPickler(f)
     p.dump(MyClass)

     del MyClass

     unpickled_class = pickle.loads(f.getvalue())

     assert isinstance(unpickled_class, type)
     assert unpickled_class.__name__ == "MyClass"
     assert unpickled_class.my_attribute == 1


File: python.info,  Node: Out-of-band Buffers,  Next: Restricting Globals,  Prev: Custom Reduction for Types Functions and Other Objects,  Up: pickle — Python object serialization

5.12.1.12 Out-of-band Buffers
.............................

Added in version 3.8.

In some contexts, the ‘pickle’ module is used to transfer massive
amounts of data.  Therefore, it can be important to minimize the number
of memory copies, to preserve performance and resource consumption.
However, normal operation of the ‘pickle’ module, as it transforms a
graph-like structure of objects into a sequential stream of bytes,
intrinsically involves copying data to and from the pickle stream.

This constraint can be eschewed if both the 'provider' (the
implementation of the object types to be transferred) and the 'consumer'
(the implementation of the communications system) support the
out-of-band transfer facilities provided by pickle protocol 5 and
higher.

* Menu:

* Provider API::
* Consumer API::
* Example: Example<4>.


File: python.info,  Node: Provider API,  Next: Consumer API,  Up: Out-of-band Buffers

5.12.1.13 Provider API
......................

The large data objects to be pickled must implement a *note
__reduce_ex__(): 16bf. method specialized for protocol 5 and higher,
which returns a *note PickleBuffer: 15c6. instance (instead of e.g.  a
*note bytes: 1c2. object) for any large data.

A *note PickleBuffer: 15c6. object 'signals' that the underlying buffer
is eligible for out-of-band data transfer.  Those objects remain
compatible with normal usage of the ‘pickle’ module.  However, consumers
can also opt-in to tell ‘pickle’ that they will handle those buffers by
themselves.


File: python.info,  Node: Consumer API,  Next: Example<4>,  Prev: Provider API,  Up: Out-of-band Buffers

5.12.1.14 Consumer API
......................

A communications system can enable custom handling of the *note
PickleBuffer: 15c6. objects generated when serializing an object graph.

On the sending side, it needs to pass a 'buffer_callback' argument to
*note Pickler: a2b. (or to the *note dump(): 2a60. or *note dumps():
14f3. function), which will be called with each *note PickleBuffer:
15c6. generated while pickling the object graph.  Buffers accumulated by
the 'buffer_callback' will not see their data copied into the pickle
stream, only a cheap marker will be inserted.

On the receiving side, it needs to pass a 'buffers' argument to *note
Unpickler: 15c4. (or to the *note load(): d38. or *note loads(): d39.
function), which is an iterable of the buffers which were passed to
'buffer_callback'.  That iterable should produce buffers in the same
order as they were passed to 'buffer_callback'.  Those buffers will
provide the data expected by the reconstructors of the objects whose
pickling produced the original *note PickleBuffer: 15c6. objects.

Between the sending side and the receiving side, the communications
system is free to implement its own transfer mechanism for out-of-band
buffers.  Potential optimizations include the use of shared memory or
datatype-dependent compression.


File: python.info,  Node: Example<4>,  Prev: Consumer API,  Up: Out-of-band Buffers

5.12.1.15 Example
.................

Here is a trivial example where we implement a *note bytearray: 2ea.
subclass able to participate in out-of-band buffer pickling:

     class ZeroCopyByteArray(bytearray):

         def __reduce_ex__(self, protocol):
             if protocol >= 5:
                 return type(self)._reconstruct, (PickleBuffer(self),), None
             else:
                 # PickleBuffer is forbidden with pickle protocols <= 4.
                 return type(self)._reconstruct, (bytearray(self),)

         @classmethod
         def _reconstruct(cls, obj):
             with memoryview(obj) as m:
                 # Get a handle over the original buffer object
                 obj = m.obj
                 if type(obj) is cls:
                     # Original buffer object is a ZeroCopyByteArray, return it
                     # as-is.
                     return obj
                 else:
                     return cls(obj)

The reconstructor (the ‘_reconstruct’ class method) returns the buffer’s
providing object if it has the right type.  This is an easy way to
simulate zero-copy behaviour on this toy example.

On the consumer side, we can pickle those objects the usual way, which
when unserialized will give us a copy of the original object:

     b = ZeroCopyByteArray(b"abc")
     data = pickle.dumps(b, protocol=5)
     new_b = pickle.loads(data)
     print(b == new_b)  # True
     print(b is new_b)  # False: a copy was made

But if we pass a 'buffer_callback' and then give back the accumulated
buffers when unserializing, we are able to get back the original object:

     b = ZeroCopyByteArray(b"abc")
     buffers = []
     data = pickle.dumps(b, protocol=5, buffer_callback=buffers.append)
     new_b = pickle.loads(data, buffers=buffers)
     print(b == new_b)  # True
     print(b is new_b)  # True: no copy was made

This example is limited by the fact that *note bytearray: 2ea. allocates
its own memory: you cannot create a ‘bytearray’ instance that is backed
by another object’s memory.  However, third-party datatypes such as
NumPy arrays do not have this limitation, and allow use of zero-copy
pickling (or making as few copies as possible) when transferring between
distinct processes or systems.

See also
........

PEP 574(1) – Pickle protocol 5 with out-of-band data

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0574/


File: python.info,  Node: Restricting Globals,  Next: Performance<2>,  Prev: Out-of-band Buffers,  Up: pickle — Python object serialization

5.12.1.16 Restricting Globals
.............................

By default, unpickling will import any class or function that it finds
in the pickle data.  For many applications, this behaviour is
unacceptable as it permits the unpickler to import and invoke arbitrary
code.  Just consider what this hand-crafted pickle data stream does when
loaded:

     >>> import pickle
     >>> pickle.loads(b"cos\nsystem\n(S'echo hello world'\ntR.")
     hello world
     0

In this example, the unpickler imports the *note os.system(): 14ac.
function and then apply the string argument “echo hello world”.
Although this example is inoffensive, it is not difficult to imagine one
that could damage your system.

For this reason, you may want to control what gets unpickled by
customizing *note Unpickler.find_class(): 2a6d.  Unlike its name
suggests, ‘Unpickler.find_class()’ is called whenever a global (i.e., a
class or a function) is requested.  Thus it is possible to either
completely forbid globals or restrict them to a safe subset.

Here is an example of an unpickler allowing only few safe classes from
the *note builtins: 12. module to be loaded:

     import builtins
     import io
     import pickle

     safe_builtins = {
         'range',
         'complex',
         'set',
         'frozenset',
         'slice',
     }

     class RestrictedUnpickler(pickle.Unpickler):

         def find_class(self, module, name):
             # Only allow safe classes from builtins.
             if module == "builtins" and name in safe_builtins:
                 return getattr(builtins, name)
             # Forbid everything else.
             raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
                                          (module, name))

     def restricted_loads(s):
         """Helper function analogous to pickle.loads()."""
         return RestrictedUnpickler(io.BytesIO(s)).load()

A sample usage of our unpickler working as intended:

     >>> restricted_loads(pickle.dumps([1, 2, range(15)]))
     [1, 2, range(0, 15)]
     >>> restricted_loads(b"cos\nsystem\n(S'echo hello world'\ntR.")
     Traceback (most recent call last):
       ...
     pickle.UnpicklingError: global 'os.system' is forbidden
     >>> restricted_loads(b'cbuiltins\neval\n'
     ...                  b'(S\'getattr(__import__("os"), "system")'
     ...                  b'("echo hello world")\'\ntR.')
     Traceback (most recent call last):
       ...
     pickle.UnpicklingError: global 'builtins.eval' is forbidden

As our examples shows, you have to be careful with what you allow to be
unpickled.  Therefore if security is a concern, you may want to consider
alternatives such as the marshalling API in *note xmlrpc.client: 12e. or
third-party solutions.


File: python.info,  Node: Performance<2>,  Next: Examples<7>,  Prev: Restricting Globals,  Up: pickle — Python object serialization

5.12.1.17 Performance
.....................

Recent versions of the pickle protocol (from protocol 2 and upwards)
feature efficient binary encodings for several common features and
built-in types.  Also, the ‘pickle’ module has a transparent optimizer
written in C.


File: python.info,  Node: Examples<7>,  Prev: Performance<2>,  Up: pickle — Python object serialization

5.12.1.18 Examples
..................

For the simplest code, use the *note dump(): 2a60. and *note load():
d38. functions.

     import pickle

     # An arbitrary collection of objects supported by pickle.
     data = {
         'a': [1, 2.0, 3+4j],
         'b': ("character string", b"byte string"),
         'c': {None, True, False}
     }

     with open('data.pickle', 'wb') as f:
         # Pickle the 'data' dictionary using the highest protocol available.
         pickle.dump(data, f, pickle.HIGHEST_PROTOCOL)

The following example reads the resulting pickled data.

     import pickle

     with open('data.pickle', 'rb') as f:
         # The protocol version used is detected automatically, so we do not
         # have to specify it.
         data = pickle.load(f)

See also
........

Module *note copyreg: 26.

     Pickle interface constructor registration for extension types.

Module *note pickletools: a7.

     Tools for working with and analyzing pickled data.

Module *note shelve: c3.

     Indexed databases of objects; uses ‘pickle’.

Module *note copy: 25.

     Shallow and deep object copying.

Module *note marshal: 8d.

     High-performance serialization of built-in types.


File: python.info,  Node: copyreg — Register pickle support functions,  Next: shelve — Python object persistence,  Prev: pickle — Python object serialization,  Up: Data Persistence

5.12.2 ‘copyreg’ — Register ‘pickle’ support functions
------------------------------------------------------

'Source code:' Lib/copyreg.py(1)

__________________________________________________________________

The ‘copyreg’ module offers a way to define functions used while
pickling specific objects.  The *note pickle: a6. and *note copy: 25.
modules use those functions when pickling/copying those objects.  The
module provides configuration information about object constructors
which are not classes.  Such constructors may be factory functions or
class instances.

 -- Function: copyreg.constructor (object)

     Declares 'object' to be a valid constructor.  If 'object' is not
     callable (and hence not valid as a constructor), raises *note
     TypeError: 2c3.

 -- Function: copyreg.pickle (type, function, constructor_ob=None)

     Declares that 'function' should be used as a “reduction” function
     for objects of type 'type'.  'function' must return either a string
     or a tuple containing between two and six elements.  See the *note
     dispatch_table: 1166. for more details on the interface of
     'function'.

     The 'constructor_ob' parameter is a legacy feature and is now
     ignored, but if passed it must be a callable.

     Note that the *note dispatch_table: 1166. attribute of a pickler
     object or subclass of *note pickle.Pickler: a2b. can also be used
     for declaring reduction functions.

* Menu:

* Example: Example<5>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/copyreg.py


File: python.info,  Node: Example<5>,  Up: copyreg — Register pickle support functions

5.12.2.1 Example
................

The example below would like to show how to register a pickle function
and how it will be used:

     >>> import copyreg, copy, pickle
     >>> class C:
     ...     def __init__(self, a):
     ...         self.a = a
     ...
     >>> def pickle_c(c):
     ...     print("pickling a C instance...")
     ...     return C, (c.a,)
     ...
     >>> copyreg.pickle(C, pickle_c)
     >>> c = C(1)
     >>> d = copy.copy(c)
     pickling a C instance...
     >>> p = pickle.dumps(c)
     pickling a C instance...


File: python.info,  Node: shelve — Python object persistence,  Next: marshal — Internal Python object serialization,  Prev: copyreg — Register pickle support functions,  Up: Data Persistence

5.12.3 ‘shelve’ — Python object persistence
-------------------------------------------

'Source code:' Lib/shelve.py(1)

__________________________________________________________________

A “shelf” is a persistent, dictionary-like object.  The difference with
“dbm” databases is that the values (not the keys!)  in a shelf can be
essentially arbitrary Python objects — anything that the *note pickle:
a6. module can handle.  This includes most class instances, recursive
data types, and objects containing lots of shared sub-objects.  The keys
are ordinary strings.

 -- Function: shelve.open (filename, flag='c', protocol=None,
          writeback=False)

     Open a persistent dictionary.  The filename specified is the base
     filename for the underlying database.  As a side-effect, an
     extension may be added to the filename and more than one file may
     be created.  By default, the underlying database file is opened for
     reading and writing.  The optional 'flag' parameter has the same
     interpretation as the 'flag' parameter of *note dbm.open(): f61.

     By default, pickles created with *note pickle.DEFAULT_PROTOCOL:
     834. are used to serialize values.  The version of the pickle
     protocol can be specified with the 'protocol' parameter.

     Because of Python semantics, a shelf cannot know when a mutable
     persistent-dictionary entry is modified.  By default modified
     objects are written 'only' when assigned to the shelf (see *note
     Example: 2a89.).  If the optional 'writeback' parameter is set to
     ‘True’, all entries accessed are also cached in memory, and written
     back on *note sync(): 2a8a. and *note close(): 2a8b.; this can make
     it handier to mutate mutable entries in the persistent dictionary,
     but, if many entries are accessed, it can consume vast amounts of
     memory for the cache, and it can make the close operation very slow
     since all accessed entries are written back (there is no way to
     determine which accessed entries are mutable, nor which ones were
     actually mutated).

     Changed in version 3.10: *note pickle.DEFAULT_PROTOCOL: 834. is now
     used as the default pickle protocol.

     Changed in version 3.11: Accepts *note path-like object: 2a0. for
     filename.

          Note: Do not rely on the shelf being closed automatically;
          always call *note close(): 2a8b. explicitly when you don’t
          need it any more, or use *note shelve.open(): 1810. as a
          context manager:

               with shelve.open('spam') as db:
                   db['eggs'] = 'eggs'
     Warning: Because the ‘shelve’ module is backed by *note pickle: a6,
     it is insecure to load a shelf from an untrusted source.  Like with
     pickle, loading a shelf can execute arbitrary code.

Shelf objects support most of the methods and operations supported by
dictionaries (except copying, constructors and operators ‘|’ and ‘|=’).
This eases the transition from dictionary based scripts to those
requiring persistent storage.

Two additional methods are supported:

 -- Method: Shelf.sync ()

     Write back all entries in the cache if the shelf was opened with
     'writeback' set to *note True: c2d.  Also empty the cache and
     synchronize the persistent dictionary on disk, if feasible.  This
     is called automatically when the shelf is closed with *note
     close(): 2a8b.

 -- Method: Shelf.close ()

     Synchronize and close the persistent 'dict' object.  Operations on
     a closed shelf will fail with a *note ValueError: 202.

See also
........

Persistent dictionary recipe(2) with widely supported storage formats
and having the speed of native dictionaries.

* Menu:

* Restrictions::
* Example: Example<6>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/shelve.py

   (2) 
https://code.activestate.com/recipes/576642-persistent-dict-with-multiple-standard-file-format/


File: python.info,  Node: Restrictions,  Next: Example<6>,  Up: shelve — Python object persistence

5.12.3.1 Restrictions
.....................

   * The choice of which database package will be used (such as *note
     dbm.ndbm: 34. or *note dbm.gnu: 33.) depends on which interface is
     available.  Therefore it is not safe to open the database directly
     using *note dbm: 31.  The database is also (unfortunately) subject
     to the limitations of ‘dbm’, if it is used — this means that (the
     pickled representation of) the objects stored in the database
     should be fairly small, and in rare cases key collisions may cause
     the database to refuse updates.

   * The ‘shelve’ module does not support 'concurrent' read/write access
     to shelved objects.  (Multiple simultaneous read accesses are
     safe.)  When a program has a shelf open for writing, no other
     program should have it open for reading or writing.  Unix file
     locking can be used to solve this, but this differs across Unix
     versions and requires knowledge about the database implementation
     used.

   * On macOS *note dbm.ndbm: 34. can silently corrupt the database file
     on updates, which can cause hard crashes when trying to read from
     the database.

 -- Class: shelve.Shelf (dict, protocol=None, writeback=False,
          keyencoding='utf-8')

     A subclass of *note collections.abc.MutableMapping: 10f0. which
     stores pickled values in the 'dict' object.

     By default, pickles created with *note pickle.DEFAULT_PROTOCOL:
     834. are used to serialize values.  The version of the pickle
     protocol can be specified with the 'protocol' parameter.  See the
     *note pickle: a6. documentation for a discussion of the pickle
     protocols.

     If the 'writeback' parameter is ‘True’, the object will hold a
     cache of all entries accessed and write them back to the 'dict' at
     sync and close times.  This allows natural operations on mutable
     entries, but can consume much more memory and make sync and close
     take a long time.

     The 'keyencoding' parameter is the encoding used to encode keys
     before they are used with the underlying dict.

     A ‘Shelf’ object can also be used as a context manager, in which
     case it will be automatically closed when the *note with: 5d5.
     block ends.

     Changed in version 3.2: Added the 'keyencoding' parameter;
     previously, keys were always encoded in UTF-8.

     Changed in version 3.4: Added context manager support.

     Changed in version 3.10: *note pickle.DEFAULT_PROTOCOL: 834. is now
     used as the default pickle protocol.

 -- Class: shelve.BsdDbShelf (dict, protocol=None, writeback=False,
          keyencoding='utf-8')

     A subclass of *note Shelf: fd4. which exposes ‘first()’, ‘next()’,
     ‘previous()’, ‘last()’ and ‘set_location()’ methods.  These are
     available in the third-party ‘bsddb’ module from pybsddb(1) but not
     in other database modules.  The 'dict' object passed to the
     constructor must support those methods.  This is generally
     accomplished by calling one of ‘bsddb.hashopen()’, ‘bsddb.btopen()’
     or ‘bsddb.rnopen()’.  The optional 'protocol', 'writeback', and
     'keyencoding' parameters have the same interpretation as for the
     ‘Shelf’ class.

 -- Class: shelve.DbfilenameShelf (filename, flag='c', protocol=None,
          writeback=False)

     A subclass of *note Shelf: fd4. which accepts a 'filename' instead
     of a dict-like object.  The underlying file will be opened using
     *note dbm.open(): f61.  By default, the file will be created and
     opened for both read and write.  The optional 'flag' parameter has
     the same interpretation as for the *note open(): 1810. function.
     The optional 'protocol' and 'writeback' parameters have the same
     interpretation as for the ‘Shelf’ class.

   ---------- Footnotes ----------

   (1) https://www.jcea.es/programacion/pybsddb.htm


File: python.info,  Node: Example<6>,  Prev: Restrictions,  Up: shelve — Python object persistence

5.12.3.2 Example
................

To summarize the interface (‘key’ is a string, ‘data’ is an arbitrary
object):

     import shelve

     d = shelve.open(filename)  # open -- file may get suffix added by low-level
                                # library

     d[key] = data              # store data at key (overwrites old data if
                                # using an existing key)
     data = d[key]              # retrieve a COPY of data at key (raise KeyError
                                # if no such key)
     del d[key]                 # delete data stored at key (raises KeyError
                                # if no such key)

     flag = key in d            # true if the key exists
     klist = list(d.keys())     # a list of all existing keys (slow!)

     # as d was opened WITHOUT writeback=True, beware:
     d['xx'] = [0, 1, 2]        # this works as expected, but...
     d['xx'].append(3)          # *this doesn't!* -- d['xx'] is STILL [0, 1, 2]!

     # having opened d without writeback=True, you need to code carefully:
     temp = d['xx']             # extracts the copy
     temp.append(5)             # mutates the copy
     d['xx'] = temp             # stores the copy right back, to persist it

     # or, d=shelve.open(filename,writeback=True) would let you just code
     # d['xx'].append(5) and have it work as expected, BUT it would also
     # consume more memory and make the d.close() operation slower.

     d.close()                  # close it

See also
........

Module *note dbm: 31.

     Generic interface to ‘dbm’-style databases.

Module *note pickle: a6.

     Object serialization used by ‘shelve’.


File: python.info,  Node: marshal — Internal Python object serialization,  Next: dbm — Interfaces to Unix “databases”,  Prev: shelve — Python object persistence,  Up: Data Persistence

5.12.4 ‘marshal’ — Internal Python object serialization
-------------------------------------------------------

__________________________________________________________________

This module contains functions that can read and write Python values in
a binary format.  The format is specific to Python, but independent of
machine architecture issues (e.g., you can write a Python value to a
file on a PC, transport the file to a Mac, and read it back there).
Details of the format are undocumented on purpose; it may change between
Python versions (although it rarely does).  (1)

This is not a general “persistence” module.  For general persistence and
transfer of Python objects through RPC calls, see the modules *note
pickle: a6. and *note shelve: c3.  The ‘marshal’ module exists mainly to
support reading and writing the “pseudo-compiled” code for Python
modules of ‘.pyc’ files.  Therefore, the Python maintainers reserve the
right to modify the marshal format in backward incompatible ways should
the need arise.  The format of code objects is not compatible between
Python versions, even if the version of the format is the same.
De-serializing a code object in the incorrect Python version has
undefined behavior.  If you’re serializing and de-serializing Python
objects, use the ‘pickle’ module instead – the performance is
comparable, version independence is guaranteed, and pickle supports a
substantially wider range of objects than marshal.

     Warning: The ‘marshal’ module is not intended to be secure against
     erroneous or maliciously constructed data.  Never unmarshal data
     received from an untrusted or unauthenticated source.

Not all Python object types are supported; in general, only objects
whose value is independent from a particular invocation of Python can be
written and read by this module.  The following types are supported:
booleans, integers, floating-point numbers, complex numbers, strings,
bytes, bytearrays, tuples, lists, sets, frozensets, dictionaries, and
code objects (if 'allow_code' is true), where it should be understood
that tuples, lists, sets, frozensets and dictionaries are only supported
as long as the values contained therein are themselves supported.  The
singletons *note None: 678, *note Ellipsis: 233f. and *note
StopIteration: c1b. can also be marshalled and unmarshalled.  For format
'version' lower than 3, recursive lists, sets and dictionaries cannot be
written (see below).

There are functions that read/write files as well as functions operating
on bytes-like objects.

The module defines these functions:

 -- Function: marshal.dump (value, file, version=version, /, *,
          allow_code=True)

     Write the value on the open file.  The value must be a supported
     type.  The file must be a writeable *note binary file: 1e26.

     If the value has (or contains an object that has) an unsupported
     type, a *note ValueError: 202. exception is raised — but garbage
     data will also be written to the file.  The object will not be
     properly read back by *note load(): 1ba4.  *note Code objects: 1d2.
     are only supported if 'allow_code' is true.

     The 'version' argument indicates the data format that ‘dump’ should
     use (see below).

     Raises an *note auditing event: 1a15. ‘marshal.dumps’ with
     arguments ‘value’, ‘version’.

     Changed in version 3.13: Added the 'allow_code' parameter.

 -- Function: marshal.load (file, /, *, allow_code=True)

     Read one value from the open file and return it.  If no valid value
     is read (e.g.  because the data has a different Python version’s
     incompatible marshal format), raise *note EOFError: 1321, *note
     ValueError: 202. or *note TypeError: 2c3.  *note Code objects: 1d2.
     are only supported if 'allow_code' is true.  The file must be a
     readable *note binary file: 1e26.

     Raises an *note auditing event: 1a15. ‘marshal.load’ with no
     arguments.

          Note: If an object containing an unsupported type was
          marshalled with *note dump(): 2a92, ‘load()’ will substitute
          ‘None’ for the unmarshallable type.

     Changed in version 3.10: This call used to raise a ‘code.__new__’
     audit event for each code object.  Now it raises a single
     ‘marshal.load’ event for the entire load operation.

     Changed in version 3.13: Added the 'allow_code' parameter.

 -- Function: marshal.dumps (value, version=version, /, *,
          allow_code=True)

     Return the bytes object that would be written to a file by
     ‘dump(value, file)’.  The value must be a supported type.  Raise a
     *note ValueError: 202. exception if value has (or contains an
     object that has) an unsupported type.  *note Code objects: 1d2. are
     only supported if 'allow_code' is true.

     The 'version' argument indicates the data format that ‘dumps’
     should use (see below).

     Raises an *note auditing event: 1a15. ‘marshal.dumps’ with
     arguments ‘value’, ‘version’.

     Changed in version 3.13: Added the 'allow_code' parameter.

 -- Function: marshal.loads (bytes, /, *, allow_code=True)

     Convert the *note bytes-like object: d55. to a value.  If no valid
     value is found, raise *note EOFError: 1321, *note ValueError: 202.
     or *note TypeError: 2c3.  *note Code objects: 1d2. are only
     supported if 'allow_code' is true.  Extra bytes in the input are
     ignored.

     Raises an *note auditing event: 1a15. ‘marshal.loads’ with argument
     ‘bytes’.

     Changed in version 3.10: This call used to raise a ‘code.__new__’
     audit event for each code object.  Now it raises a single
     ‘marshal.loads’ event for the entire load operation.

     Changed in version 3.13: Added the 'allow_code' parameter.

In addition, the following constants are defined:

 -- Data: marshal.version

     Indicates the format that the module uses.  Version 0 is the
     historical format, version 1 shares interned strings and version 2
     uses a binary format for floating-point numbers.  Version 3 adds
     support for object instancing and recursion.  The current version
     is 4.

   ---------- Footnotes ----------

   (1) The name of this module stems from a bit of terminology used by
the designers of Modula-3 (amongst others), who use the term
“marshalling” for shipping of data around in a self-contained form.
Strictly speaking, “to marshal” means to convert some data from internal
to external form (in an RPC buffer for instance) and “unmarshalling” for
the reverse process.


File: python.info,  Node: dbm — Interfaces to Unix “databases”,  Next: sqlite3 — DB-API 2 0 interface for SQLite databases,  Prev: marshal — Internal Python object serialization,  Up: Data Persistence

5.12.5 ‘dbm’ — Interfaces to Unix “databases”
---------------------------------------------

'Source code:' Lib/dbm/__init__.py(1)

__________________________________________________________________

‘dbm’ is a generic interface to variants of the DBM database:

   * *note dbm.sqlite3: 35.

   * *note dbm.gnu: 33.

   * *note dbm.ndbm: 34.

If none of these modules are installed, the slow-but-simple
implementation in module *note dbm.dumb: 32. will be used.  There is a
third party interface(2) to the Oracle Berkeley DB.

 -- Exception: dbm.error

     A tuple containing the exceptions that can be raised by each of the
     supported modules, with a unique exception also named *note
     dbm.error: 2a98. as the first item — the latter is used when
     ‘dbm.error’ is raised.

 -- Function: dbm.whichdb (filename)

     This function attempts to guess which of the several simple
     database modules available — *note dbm.sqlite3: 35, *note dbm.gnu:
     33, *note dbm.ndbm: 34, or *note dbm.dumb: 32. — should be used to
     open a given file.

     Return one of the following values:

        * ‘None’ if the file can’t be opened because it’s unreadable or
          doesn’t exist

        * the empty string (‘''’) if the file’s format can’t be guessed

        * a string containing the required module name, such as
          ‘'dbm.ndbm'’ or ‘'dbm.gnu'’

     Changed in version 3.11: 'filename' accepts a *note path-like
     object: 2a0.

 -- Function: dbm.open (file, flag='r', mode=0o666)

     Open a database and return the corresponding database object.


     Parameters:

        * ‘file’ (*note path-like object: 2a0.) – The database file to
          open.

          If the database file already exists, the *note whichdb():
          2a99. function is used to determine its type and the
          appropriate module is used; if it does not exist, the first
          submodule listed above that can be imported is used.

        * ‘flag’ (*note str: 44f.) –

             * ‘'r'’ (default): Open existing database for reading only.

             * ‘'w'’: Open existing database for reading and writing.

             * ‘'c'’: Open database for reading and writing, creating it
               if it doesn’t exist.

             * ‘'n'’: Always create a new, empty database, open for
               reading and writing.

        * ‘mode’ (*note int: 257.) – The Unix file access mode of the
          file (default: octal ‘0o666’), used only when the database has
          to be created.

     Changed in version 3.11: 'file' accepts a *note path-like object:
     2a0.

The object returned by *note open(): f61. supports the basic
functionality of mutable *note mappings: 1200.; keys and their
corresponding values can be stored, retrieved, and deleted, and
iteration, the *note in: 2f4. operator and methods ‘keys()’, ‘get()’,
‘setdefault()’ and ‘clear()’ are available.  The ‘keys()’ method returns
a list instead of a view object.  The ‘setdefault()’ method requires two
arguments.

Key and values are always stored as *note bytes: 1c2.  This means that
when strings are used they are implicitly converted to the default
encoding before being stored.

These objects also support being used in a *note with: 5d5. statement,
which will automatically close them when done.

Changed in version 3.2: ‘get()’ and ‘setdefault()’ methods are now
available for all ‘dbm’ backends.

Changed in version 3.4: Added native support for the context management
protocol to the objects returned by *note open(): f61.

Changed in version 3.8: Deleting a key from a read-only database raises
a database module specific exception instead of *note KeyError: 345.

Changed in version 3.13: ‘clear()’ methods are now available for all
‘dbm’ backends.

The following example records some hostnames and a corresponding title,
and then prints out the contents of the database:

     import dbm

     # Open database, creating it if necessary.
     with dbm.open('cache', 'c') as db:

         # Record some values
         db[b'hello'] = b'there'
         db['www.python.org'] = 'Python Website'
         db['www.cnn.com'] = 'Cable News Network'

         # Note that the keys are considered bytes now.
         assert db[b'www.python.org'] == b'Python Website'
         # Notice how the value is now in bytes.
         assert db['www.cnn.com'] == b'Cable News Network'

         # Often-used methods of the dict interface work too.
         print(db.get('python.org', b'not present'))

         # Storing a non-string key or value will raise an exception (most
         # likely a TypeError).
         db['www.yahoo.com'] = 4

     # db is automatically closed when leaving the with statement.

See also
........

Module *note shelve: c3.

     Persistence module which stores non-string data.

The individual submodules are described in the following sections.

* Menu:

* dbm.sqlite3 — SQLite backend for dbm: dbm sqlite3 — SQLite backend for dbm.
* dbm.gnu — GNU database manager: dbm gnu — GNU database manager.
* dbm.ndbm — New Database Manager: dbm ndbm — New Database Manager.
* dbm.dumb — Portable DBM implementation: dbm dumb — Portable DBM implementation.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dbm/__init__.py

   (2) https://www.jcea.es/programacion/pybsddb.htm


File: python.info,  Node: dbm sqlite3 — SQLite backend for dbm,  Next: dbm gnu — GNU database manager,  Up: dbm — Interfaces to Unix “databases”

5.12.5.1 ‘dbm.sqlite3’ — SQLite backend for dbm
...............................................

Added in version 3.13.

'Source code:' Lib/dbm/sqlite3.py(1)

__________________________________________________________________

This module uses the standard library *note sqlite3: cf. module to
provide an SQLite backend for the ‘dbm’ module.  The files created by
‘dbm.sqlite3’ can thus be opened by ‘sqlite3’, or any other SQLite
browser, including the SQLite CLI.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

 -- Function: dbm.sqlite3.open (filename, /, flag='r', mode=0o666)

     Open an SQLite database.


     Parameters:

        * ‘filename’ (*note path-like object: 2a0.) – The path to the
          database to be opened.

        * ‘flag’ (*note str: 44f.) –

             * ‘'r'’ (default): Open existing database for reading only.

             * ‘'w'’: Open existing database for reading and writing.

             * ‘'c'’: Open database for reading and writing, creating it
               if it doesn’t exist.

             * ‘'n'’: Always create a new, empty database, open for
               reading and writing.

        * ‘mode’ – The Unix file access mode of the file (default: octal
          ‘0o666’), used only when the database has to be created.

     The returned database object behaves similar to a mutable *note
     mapping: 1200, but the ‘keys()’ method returns a list, and the
     ‘setdefault()’ method requires two arguments.  It also supports a
     “closing” context manager via the *note with: 5d5. keyword.

     The following method is also provided:

      -- Method: sqlite3.close ()

          Close the SQLite database.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dbm/sqlite3.py


File: python.info,  Node: dbm gnu — GNU database manager,  Next: dbm ndbm — New Database Manager,  Prev: dbm sqlite3 — SQLite backend for dbm,  Up: dbm — Interfaces to Unix “databases”

5.12.5.2 ‘dbm.gnu’ — GNU database manager
.........................................

'Source code:' Lib/dbm/gnu.py(1)

__________________________________________________________________

The ‘dbm.gnu’ module provides an interface to the GDBM (GNU dbm)
library, similar to the *note dbm.ndbm: 34. module, but with additional
functionality like crash tolerance.

     Note: The file formats created by ‘dbm.gnu’ and *note dbm.ndbm: 34.
     are incompatible and can not be used interchangeably.

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

*note Availability: 1ef7.: Unix.

 -- Exception: dbm.gnu.error

     Raised on ‘dbm.gnu’-specific errors, such as I/O errors.  *note
     KeyError: 345. is raised for general mapping errors like specifying
     an incorrect key.

 -- Data: dbm.gnu.open_flags

     A string of characters the 'flag' parameter of *note open(): 1bcf.
     supports.

 -- Function: dbm.gnu.open (filename, flag='r', mode=0o666, /)

     Open a GDBM database and return a ‘gdbm’ object.


     Parameters:

        * ‘filename’ (*note path-like object: 2a0.) – The database file
          to open.

        * ‘flag’ (*note str: 44f.) –

             * ‘'r'’ (default): Open existing database for reading only.

             * ‘'w'’: Open existing database for reading and writing.

             * ‘'c'’: Open database for reading and writing, creating it
               if it doesn’t exist.

             * ‘'n'’: Always create a new, empty database, open for
               reading and writing.

          The following additional characters may be appended to control
          how the database is opened:

             * ‘'f'’: Open the database in fast mode.  Writes to the
               database will not be synchronized.

             * ‘'s'’: Synchronized mode.  Changes to the database will
               be written immediately to the file.

             * ‘'u'’: Do not lock database.

          Not all flags are valid for all versions of GDBM. See the
          *note open_flags: 2a9e. member for a list of supported flag
          characters.

        * ‘mode’ (*note int: 257.) – The Unix file access mode of the
          file (default: octal ‘0o666’), used only when the database has
          to be created.


     Raises: *note error: aaf. – If an invalid 'flag' argument is
     passed.

     Changed in version 3.11: 'filename' accepts a *note path-like
     object: 2a0.

     ‘gdbm’ objects behave similar to mutable *note mappings: 1200, but
     methods ‘items()’, ‘values()’, ‘pop()’, ‘popitem()’, and ‘update()’
     are not supported, the ‘keys()’ method returns a list, and the
     ‘setdefault()’ method requires two arguments.  It also supports a
     “closing” context manager via the *note with: 5d5. keyword.

     Changed in version 3.2: Added the ‘get()’ and ‘setdefault()’
     methods.

     Changed in version 3.13: Added the ‘clear()’ method.

     The following methods are also provided:

      -- Method: gdbm.close ()

          Close the GDBM database.

      -- Method: gdbm.firstkey ()

          It’s possible to loop over every key in the database using
          this method and the *note nextkey(): 2aa1. method.  The
          traversal is ordered by GDBM’s internal hash values, and won’t
          be sorted by the key values.  This method returns the starting
          key.

      -- Method: gdbm.nextkey (key)

          Returns the key that follows 'key' in the traversal.  The
          following code prints every key in the database ‘db’, without
          having to create a list in memory that contains them all:

               k = db.firstkey()
               while k is not None:
                   print(k)
                   k = db.nextkey(k)

      -- Method: gdbm.reorganize ()

          If you have carried out a lot of deletions and would like to
          shrink the space used by the GDBM file, this routine will
          reorganize the database.  ‘gdbm’ objects will not shorten the
          length of a database file except by using this reorganization;
          otherwise, deleted file space will be kept and reused as new
          (key, value) pairs are added.

      -- Method: gdbm.sync ()

          When the database has been opened in fast mode, this method
          forces any unwritten data to be written to the disk.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dbm/gnu.py


File: python.info,  Node: dbm ndbm — New Database Manager,  Next: dbm dumb — Portable DBM implementation,  Prev: dbm gnu — GNU database manager,  Up: dbm — Interfaces to Unix “databases”

5.12.5.3 ‘dbm.ndbm’ — New Database Manager
..........................................

'Source code:' Lib/dbm/ndbm.py(1)

__________________________________________________________________

The ‘dbm.ndbm’ module provides an interface to the NDBM (New Database
Manager) library.  This module can be used with the “classic” NDBM
interface or the GDBM compatibility interface.

     Note: The file formats created by *note dbm.gnu: 33. and ‘dbm.ndbm’
     are incompatible and can not be used interchangeably.

     Warning: The NDBM library shipped as part of macOS has an
     undocumented limitation on the size of values, which can result in
     corrupted database files when storing values larger than this
     limit.  Reading such corrupted files can result in a hard crash
     (segmentation fault).

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

*note Availability: 1ef7.: Unix.

 -- Exception: dbm.ndbm.error

     Raised on ‘dbm.ndbm’-specific errors, such as I/O errors.  *note
     KeyError: 345. is raised for general mapping errors like specifying
     an incorrect key.

 -- Data: dbm.ndbm.library

     Name of the NDBM implementation library used.

 -- Function: dbm.ndbm.open (filename, flag='r', mode=0o666, /)

     Open an NDBM database and return an ‘ndbm’ object.


     Parameters:

        * ‘filename’ (*note path-like object: 2a0.) – The basename of
          the database file (without the ‘.dir’ or ‘.pag’ extensions).

        * ‘flag’ (*note str: 44f.) –

             * ‘'r'’ (default): Open existing database for reading only.

             * ‘'w'’: Open existing database for reading and writing.

             * ‘'c'’: Open database for reading and writing, creating it
               if it doesn’t exist.

             * ‘'n'’: Always create a new, empty database, open for
               reading and writing.

        * ‘mode’ (*note int: 257.) – The Unix file access mode of the
          file (default: octal ‘0o666’), used only when the database has
          to be created.

     Changed in version 3.11: Accepts *note path-like object: 2a0. for
     filename.

     ‘ndbm’ objects behave similar to mutable *note mappings: 1200, but
     methods ‘items()’, ‘values()’, ‘pop()’, ‘popitem()’, and ‘update()’
     are not supported, the ‘keys()’ method returns a list, and the
     ‘setdefault()’ method requires two arguments.  It also supports a
     “closing” context manager via the *note with: 5d5. keyword.

     Changed in version 3.2: Added the ‘get()’ and ‘setdefault()’
     methods.

     Changed in version 3.13: Added the ‘clear()’ method.

     The following method is also provided:

      -- Method: ndbm.close ()

          Close the NDBM database.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dbm/ndbm.py


File: python.info,  Node: dbm dumb — Portable DBM implementation,  Prev: dbm ndbm — New Database Manager,  Up: dbm — Interfaces to Unix “databases”

5.12.5.4 ‘dbm.dumb’ — Portable DBM implementation
.................................................

'Source code:' Lib/dbm/dumb.py(1)

     Note: The ‘dbm.dumb’ module is intended as a last resort fallback
     for the ‘dbm’ module when a more robust module is not available.
     The ‘dbm.dumb’ module is not written for speed and is not nearly as
     heavily used as the other database modules.

__________________________________________________________________

The ‘dbm.dumb’ module provides a persistent *note dict: 256.-like
interface which is written entirely in Python.  Unlike other ‘dbm’
backends, such as *note dbm.gnu: 33, no external library is required.

The ‘dbm.dumb’ module defines the following:

 -- Exception: dbm.dumb.error

     Raised on ‘dbm.dumb’-specific errors, such as I/O errors.  *note
     KeyError: 345. is raised for general mapping errors like specifying
     an incorrect key.

 -- Function: dbm.dumb.open (filename, flag='c', mode=0o666)

     Open a ‘dbm.dumb’ database.


     Parameters:

        * ‘filename’ – The basename of the database file (without
          extensions).  A new database creates the following files:

             - ‘`filename'.dat’

             - ‘`filename'.dir’

        * ‘flag’ (*note str: 44f.) –

             * ‘'r'’: Open existing database for reading only.

             * ‘'w'’: Open existing database for reading and writing.

             * ‘'c'’ (default): Open database for reading and writing,
               creating it if it doesn’t exist.

             * ‘'n'’: Always create a new, empty database, open for
               reading and writing.

        * ‘mode’ (*note int: 257.) – The Unix file access mode of the
          file (default: octal ‘0o666’), used only when the database has
          to be created.

          Warning: It is possible to crash the Python interpreter when
          loading a database with a sufficiently large/complex entry due
          to stack depth limitations in Python’s AST compiler.

     Changed in version 3.5: *note open(): aab. always creates a new
     database when 'flag' is ‘'n'’.

     Changed in version 3.8: A database opened read-only if 'flag' is
     ‘'r'’.  A database is not created if it does not exist if 'flag' is
     ‘'r'’ or ‘'w'’.

     Changed in version 3.11: 'filename' accepts a *note path-like
     object: 2a0.

     The returned database object behaves similar to a mutable *note
     mapping: 1200, but the ‘keys()’ and ‘items()’ methods return lists,
     and the ‘setdefault()’ method requires two arguments.  It also
     supports a “closing” context manager via the *note with: 5d5.
     keyword.

     The following methods are also provided:

      -- Method: dumbdbm.close ()

          Close the database.

      -- Method: dumbdbm.sync ()

          Synchronize the on-disk directory and data files.  This method
          is called by the *note shelve.Shelf.sync(): 2a8a. method.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dbm/dumb.py


File: python.info,  Node: sqlite3 — DB-API 2 0 interface for SQLite databases,  Prev: dbm — Interfaces to Unix “databases”,  Up: Data Persistence

5.12.6 ‘sqlite3’ — DB-API 2.0 interface for SQLite databases
------------------------------------------------------------

'Source code:' Lib/sqlite3/(1)

SQLite is a C library that provides a lightweight disk-based database
that doesn’t require a separate server process and allows accessing the
database using a nonstandard variant of the SQL query language.  Some
applications can use SQLite for internal data storage.  It’s also
possible to prototype an application using SQLite and then port the code
to a larger database such as PostgreSQL or Oracle.

The ‘sqlite3’ module was written by Gerhard Häring.  It provides an SQL
interface compliant with the DB-API 2.0 specification described by PEP
249(2), and requires SQLite 3.15.2 or newer.

This document includes four main sections:

   * *note Tutorial: 2aae. teaches how to use the ‘sqlite3’ module.

   * *note Reference: 2aaf. describes the classes and functions this
     module defines.

   * *note How-to guides: 2ab0. details how to handle specific tasks.

   * *note Explanation: 2ab1. provides in-depth background on
     transaction control.

See also
........

‘https://www.sqlite.org’

     The SQLite web page; the documentation describes the syntax and the
     available data types for the supported SQL dialect.

‘https://www.w3schools.com/sql/’

     Tutorial, reference and examples for learning SQL syntax.

PEP 249(3) - Database API Specification 2.0

     PEP written by Marc-André Lemburg.

* Menu:

* Tutorial::
* Reference::
* How-to guides::
* Explanation::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/sqlite3/

   (2) https://peps.python.org/pep-0249/

   (3) https://peps.python.org/pep-0249/


File: python.info,  Node: Tutorial,  Next: Reference,  Up: sqlite3 — DB-API 2 0 interface for SQLite databases

5.12.6.1 Tutorial
.................

In this tutorial, you will create a database of Monty Python movies
using basic ‘sqlite3’ functionality.  It assumes a fundamental
understanding of database concepts, including cursors(1) and
transactions(2).

First, we need to create a new database and open a database connection
to allow ‘sqlite3’ to work with it.  Call *note sqlite3.connect(): 2a8.
to create a connection to the database ‘tutorial.db’ in the current
working directory, implicitly creating it if it does not exist:

     import sqlite3
     con = sqlite3.connect("tutorial.db")

The returned *note Connection: 245. object ‘con’ represents the
connection to the on-disk database.

In order to execute SQL statements and fetch results from SQL queries,
we will need to use a database cursor.  Call *note con.cursor(): 2ab3.
to create the *note Cursor: 2ab4.:

     cur = con.cursor()

Now that we’ve got a database connection and a cursor, we can create a
database table ‘movie’ with columns for title, release year, and review
score.  For simplicity, we can just use column names in the table
declaration – thanks to the flexible typing(3) feature of SQLite,
specifying the data types is optional.  Execute the ‘CREATE TABLE’
statement by calling *note cur.execute(...): 2d1.:

     cur.execute("CREATE TABLE movie(title, year, score)")

We can verify that the new table has been created by querying the
‘sqlite_master’ table built-in to SQLite, which should now contain an
entry for the ‘movie’ table definition (see The Schema Table(4) for
details).  Execute that query by calling *note cur.execute(...): 2d1,
assign the result to ‘res’, and call *note res.fetchone(): 2ab5. to
fetch the resulting row:

     >>> res = cur.execute("SELECT name FROM sqlite_master")
     >>> res.fetchone()
     ('movie',)

We can see that the table has been created, as the query returns a *note
tuple: 373. containing the table’s name.  If we query ‘sqlite_master’
for a non-existent table ‘spam’, ‘res.fetchone()’ will return ‘None’:

     >>> res = cur.execute("SELECT name FROM sqlite_master WHERE name='spam'")
     >>> res.fetchone() is None
     True

Now, add two rows of data supplied as SQL literals by executing an
‘INSERT’ statement, once again by calling *note cur.execute(...): 2d1.:

     cur.execute("""
         INSERT INTO movie VALUES
             ('Monty Python and the Holy Grail', 1975, 8.2),
             ('And Now for Something Completely Different', 1971, 7.5)
     """)

The ‘INSERT’ statement implicitly opens a transaction, which needs to be
committed before changes are saved in the database (see *note
Transaction control: 2ab6. for details).  Call *note con.commit(): 2ab7.
on the connection object to commit the transaction:

     con.commit()

We can verify that the data was inserted correctly by executing a
‘SELECT’ query.  Use the now-familiar *note cur.execute(...): 2d1. to
assign the result to ‘res’, and call *note res.fetchall(): 2ab8. to
return all resulting rows:

     >>> res = cur.execute("SELECT score FROM movie")
     >>> res.fetchall()
     [(8.2,), (7.5,)]

The result is a *note list: 614. of two ‘tuple’s, one per row, each
containing that row’s ‘score’ value.

Now, insert three more rows by calling *note cur.executemany(...): 2d2.:

     data = [
         ("Monty Python Live at the Hollywood Bowl", 1982, 7.9),
         ("Monty Python's The Meaning of Life", 1983, 7.5),
         ("Monty Python's Life of Brian", 1979, 8.0),
     ]
     cur.executemany("INSERT INTO movie VALUES(?, ?, ?)", data)
     con.commit()  # Remember to commit the transaction after executing INSERT.

Notice that ‘?’ placeholders are used to bind ‘data’ to the query.
Always use placeholders instead of *note string formatting: 1e12. to
bind Python values to SQL statements, to avoid SQL injection attacks(5)
(see *note How to use placeholders to bind values in SQL queries: 2d3.
for more details).

We can verify that the new rows were inserted by executing a ‘SELECT’
query, this time iterating over the results of the query:

     >>> for row in cur.execute("SELECT year, title FROM movie ORDER BY year"):
     ...     print(row)
     (1971, 'And Now for Something Completely Different')
     (1975, 'Monty Python and the Holy Grail')
     (1979, "Monty Python's Life of Brian")
     (1982, 'Monty Python Live at the Hollywood Bowl')
     (1983, "Monty Python's The Meaning of Life")

Each row is a two-item *note tuple: 373. of ‘(year, title)’, matching
the columns selected in the query.

Finally, verify that the database has been written to disk by calling
*note con.close(): 246. to close the existing connection, opening a new
one, creating a new cursor, then querying the database:

     >>> con.close()
     >>> new_con = sqlite3.connect("tutorial.db")
     >>> new_cur = new_con.cursor()
     >>> res = new_cur.execute("SELECT title, year FROM movie ORDER BY score DESC")
     >>> title, year = res.fetchone()
     >>> print(f'The highest scoring Monty Python movie is {title!r}, released in {year}')
     The highest scoring Monty Python movie is 'Monty Python and the Holy Grail', released in 1975
     >>> new_con.close()

You’ve now created an SQLite database using the ‘sqlite3’ module,
inserted data and retrieved values from it in multiple ways.

See also
........

   * *note How-to guides: 2ab0. for further reading:

        * *note How to use placeholders to bind values in SQL queries:
          2d3.

        * *note How to adapt custom Python types to SQLite values: 2ab9.

        * *note How to convert SQLite values to custom Python types:
          2aba.

        * *note How to use the connection context manager: 1912.

        * *note How to create and use row factories: 2abb.

   * *note Explanation: 2ab1. for in-depth background on transaction
     control.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Cursor_(databases)

   (2) https://en.wikipedia.org/wiki/Database_transaction

   (3) https://www.sqlite.org/flextypegood.html

   (4) https://www.sqlite.org/schematab.html

   (5) https://en.wikipedia.org/wiki/SQL_injection


File: python.info,  Node: Reference,  Next: How-to guides,  Prev: Tutorial,  Up: sqlite3 — DB-API 2 0 interface for SQLite databases

5.12.6.2 Reference
..................

* Menu:

* Module functions::
* Module constants::
* Connection objects::
* Cursor objects::
* Row objects::
* Blob objects::
* PrepareProtocol objects::
* Exceptions: Exceptions<7>.
* SQLite and Python types::
* Default adapters and converters (deprecated): Default adapters and converters deprecated.
* Command-line interface::


File: python.info,  Node: Module functions,  Next: Module constants,  Up: Reference

5.12.6.3 Module functions
.........................

 -- Function: sqlite3.connect (database, timeout=5.0, detect_types=0,
          isolation_level='DEFERRED', check_same_thread=True,
          factory=sqlite3.Connection, cached_statements=128, uri=False,
          *, autocommit=sqlite3.LEGACY_TRANSACTION_CONTROL)

     Open a connection to an SQLite database.


     Parameters:

        * ‘database’ (*note path-like object: 2a0.) – The path to the
          database file to be opened.  You can pass ‘":memory:"’ to
          create an SQLite database existing only in memory(1), and open
          a connection to it.

        * ‘timeout’ (*note float: 2f7.) – How many seconds the
          connection should wait before raising an *note
          OperationalError: 19f8. when a table is locked.  If another
          connection opens a transaction to modify a table, that table
          will be locked until the transaction is committed.  Default
          five seconds.

        * ‘detect_types’ (*note int: 257.) – Control whether and how
          data types not *note natively supported by SQLite: 2ac0. are
          looked up to be converted to Python types, using the
          converters registered with *note register_converter(): 2ac1.
          Set it to any combination (using ‘|’, bitwise or) of *note
          PARSE_DECLTYPES: 2ac2. and *note PARSE_COLNAMES: 2ac3. to
          enable this.  Column names take precedence over declared types
          if both flags are set.  By default (‘0’), type detection is
          disabled.

        * ‘isolation_level’ (*note str: 44f.‘ | ’‘None’) – Control
          legacy transaction handling behaviour.  See *note
          Connection.isolation_level: 2ac4. and *note Transaction
          control via the isolation_level attribute: 2ac5. for more
          information.  Can be ‘"DEFERRED"’ (default), ‘"EXCLUSIVE"’ or
          ‘"IMMEDIATE"’; or ‘None’ to disable opening transactions
          implicitly.  Has no effect unless *note Connection.autocommit:
          4b9. is set to *note LEGACY_TRANSACTION_CONTROL: 2ac6. (the
          default).

        * ‘check_same_thread’ (*note bool: 46b.) – If ‘True’ (default),
          *note ProgrammingError: 4f5. will be raised if the database
          connection is used by a thread other than the one that created
          it.  If ‘False’, the connection may be accessed in multiple
          threads; write operations may need to be serialized by the
          user to avoid data corruption.  See *note threadsafety: 67f.
          for more information.

        * ‘factory’ (*note Connection: 245.) – A custom subclass of
          *note Connection: 245. to create the connection with, if not
          the default ‘Connection’ class.

        * ‘cached_statements’ (*note int: 257.) – The number of
          statements that ‘sqlite3’ should internally cache for this
          connection, to avoid parsing overhead.  By default, 128
          statements.

        * ‘uri’ (*note bool: 46b.) – If set to ‘True’, 'database' is
          interpreted as a URI (Uniform Resource Identifier) with a file
          path and an optional query string.  The scheme part 'must' be
          ‘"file:"’, and the path can be relative or absolute.  The
          query string allows passing parameters to SQLite, enabling
          various *note How to work with SQLite URIs: 2ac7.

        * ‘autocommit’ (*note bool: 46b.) – Control PEP 249(2)
          transaction handling behaviour.  See *note
          Connection.autocommit: 4b9. and *note Transaction control via
          the autocommit attribute: 4ba. for more information.
          'autocommit' currently defaults to *note
          LEGACY_TRANSACTION_CONTROL: 2ac6.  The default will change to
          ‘False’ in a future Python release.


     Return type: *note Connection: 245.

     Raises an *note auditing event: 1a15. ‘sqlite3.connect’ with
     argument ‘database’.

     Raises an *note auditing event: 1a15. ‘sqlite3.connect/handle’ with
     argument ‘connection_handle’.

     Changed in version 3.4: Added the 'uri' parameter.

     Changed in version 3.7: 'database' can now also be a *note
     path-like object: 2a0, not only a string.

     Changed in version 3.10: Added the ‘sqlite3.connect/handle’
     auditing event.

     Changed in version 3.12: Added the 'autocommit' parameter.

     Changed in version 3.13: Positional use of the parameters
     'timeout', 'detect_types', 'isolation_level', 'check_same_thread',
     'factory', 'cached_statements', and 'uri' is deprecated.  They will
     become keyword-only parameters in Python 3.15.

 -- Function: sqlite3.complete_statement (statement)

     Return ‘True’ if the string 'statement' appears to contain one or
     more complete SQL statements.  No syntactic verification or parsing
     of any kind is performed, other than checking that there are no
     unclosed string literals and the statement is terminated by a
     semicolon.

     For example:

          >>> sqlite3.complete_statement("SELECT foo FROM bar;")
          True
          >>> sqlite3.complete_statement("SELECT foo")
          False

     This function may be useful during command-line input to determine
     if the entered text seems to form a complete SQL statement, or if
     additional input is needed before calling *note execute(): 2d1.

     See ‘runsource()’ in Lib/sqlite3/__main__.py(3) for real-world use.

 -- Function: sqlite3.enable_callback_tracebacks (flag, /)

     Enable or disable callback tracebacks.  By default you will not get
     any tracebacks in user-defined functions, aggregates, converters,
     authorizer callbacks etc.  If you want to debug them, you can call
     this function with 'flag' set to ‘True’.  Afterwards, you will get
     tracebacks from callbacks on *note sys.stderr: 943.  Use ‘False’ to
     disable the feature again.

          Note: Errors in user-defined function callbacks are logged as
          unraisable exceptions.  Use an *note unraisable hook handler:
          1f7. for introspection of the failed callback.

 -- Function: sqlite3.register_adapter (type, adapter, /)

     Register an 'adapter' *note callable: 2acb. to adapt the Python
     type 'type' into an SQLite type.  The adapter is called with a
     Python object of type 'type' as its sole argument, and must return
     a value of a *note type that SQLite natively understands: 2ac0.

 -- Function: sqlite3.register_converter (typename, converter, /)

     Register the 'converter' *note callable: 2acb. to convert SQLite
     objects of type 'typename' into a Python object of a specific type.
     The converter is invoked for all SQLite values of type 'typename';
     it is passed a *note bytes: 1c2. object and should return an object
     of the desired Python type.  Consult the parameter 'detect_types'
     of *note connect(): 2a8. for information regarding how type
     detection works.

     Note: 'typename' and the name of the type in your query are matched
     case-insensitively.

   ---------- Footnotes ----------

   (1) https://sqlite.org/inmemorydb.html

   (2) https://peps.python.org/pep-0249/

   (3) 
https://github.com/python/cpython/tree/3.13/Lib/sqlite3/__main__.py


File: python.info,  Node: Module constants,  Next: Connection objects,  Prev: Module functions,  Up: Reference

5.12.6.4 Module constants
.........................

 -- Data: sqlite3.LEGACY_TRANSACTION_CONTROL

     Set *note autocommit: 4b9. to this constant to select old style
     (pre-Python 3.12) transaction control behaviour.  See *note
     Transaction control via the isolation_level attribute: 2ac5. for
     more information.

 -- Data: sqlite3.PARSE_DECLTYPES

     Pass this flag value to the 'detect_types' parameter of *note
     connect(): 2a8. to look up a converter function using the declared
     types for each column.  The types are declared when the database
     table is created.  ‘sqlite3’ will look up a converter function
     using the first word of the declared type as the converter
     dictionary key.  For example:

          CREATE TABLE test(
             i integer primary key,  ! will look up a converter named "integer"
             p point,                ! will look up a converter named "point"
             n number(10)            ! will look up a converter named "number"
           )

     This flag may be combined with *note PARSE_COLNAMES: 2ac3. using
     the ‘|’ (bitwise or) operator.

          Note: Generated fields (for example ‘MAX(p)’) are returned as
          *note str: 44f.  Use ‘PARSE_COLNAMES’ to enforce types for
          such queries.

 -- Data: sqlite3.PARSE_COLNAMES

     Pass this flag value to the 'detect_types' parameter of *note
     connect(): 2a8. to look up a converter function by using the type
     name, parsed from the query column name, as the converter
     dictionary key.  The query column name must be wrapped in double
     quotes (‘"’) and the type name must be wrapped in square brackets
     (‘[]’).

          SELECT MAX(p) as "p [point]" FROM test;  ! will look up converter "point"

     This flag may be combined with *note PARSE_DECLTYPES: 2ac2. using
     the ‘|’ (bitwise or) operator.

 -- Data: sqlite3.SQLITE_OK
 -- Data: sqlite3.SQLITE_DENY
 -- Data: sqlite3.SQLITE_IGNORE

     Flags that should be returned by the 'authorizer_callback' *note
     callable: 2acb. passed to *note Connection.set_authorizer(): 2ab,
     to indicate whether:

        * Access is allowed (‘SQLITE_OK’),

        * The SQL statement should be aborted with an error
          (‘SQLITE_DENY’)

        * The column should be treated as a ‘NULL’ value
          (‘SQLITE_IGNORE’)

 -- Data: sqlite3.apilevel

     String constant stating the supported DB-API level.  Required by
     the DB-API. Hard-coded to ‘"2.0"’.

 -- Data: sqlite3.paramstyle

     String constant stating the type of parameter marker formatting
     expected by the ‘sqlite3’ module.  Required by the DB-API.
     Hard-coded to ‘"qmark"’.

          Note: The ‘named’ DB-API parameter style is also supported.

 -- Data: sqlite3.sqlite_version

     Version number of the runtime SQLite library as a *note string:
     44f.

 -- Data: sqlite3.sqlite_version_info

     Version number of the runtime SQLite library as a *note tuple: 373.
     of *note integers: 257.

 -- Data: sqlite3.threadsafety

     Integer constant required by the DB-API 2.0, stating the level of
     thread safety the ‘sqlite3’ module supports.  This attribute is set
     based on the default threading mode(1) the underlying SQLite
     library is compiled with.  The SQLite threading modes are:

       1. 'Single-thread': In this mode, all mutexes are disabled and
          SQLite is unsafe to use in more than a single thread at once.

       2. 'Multi-thread': In this mode, SQLite can be safely used by
          multiple threads provided that no single database connection
          is used simultaneously in two or more threads.

       3. 'Serialized': In serialized mode, SQLite can be safely used by
          multiple threads with no restriction.

     The mappings from SQLite threading modes to DB-API 2.0 threadsafety
     levels are as follows:

     SQLite threading       threadsafety(2)            SQLITE_THREADSAFE(3)       DB-API 2.0 meaning
     mode                                                                         

     -----------------------------------------------------------------------------------------------------------------
                                                                                  
     single-thread          0                          0                          Threads may not share the module
                                                                                  
                                                                                  
     multi-thread           1                          2                          Threads may share the module, but
                                                                                  not connections
                                                                                  
                                                                                  
     serialized             3                          1                          Threads may share the module,
                                                                                  connections and cursors
                                                                                  

     Changed in version 3.11: Set 'threadsafety' dynamically instead of
     hard-coding it to ‘1’.

 -- Data: sqlite3.version

     Version number of this module as a *note string: 44f.  This is not
     the version of the SQLite library.

     Deprecated since version 3.12, will be removed in version 3.14:
     This constant used to reflect the version number of the ‘pysqlite’
     package, a third-party library which used to upstream changes to
     ‘sqlite3’.  Today, it carries no meaning or practical value.

 -- Data: sqlite3.version_info

     Version number of this module as a *note tuple: 373. of *note
     integers: 257.  This is not the version of the SQLite library.

     Deprecated since version 3.12, will be removed in version 3.14:
     This constant used to reflect the version number of the ‘pysqlite’
     package, a third-party library which used to upstream changes to
     ‘sqlite3’.  Today, it carries no meaning or practical value.

 -- Data: sqlite3.SQLITE_DBCONFIG_DEFENSIVE
 -- Data: sqlite3.SQLITE_DBCONFIG_DQS_DDL
 -- Data: sqlite3.SQLITE_DBCONFIG_DQS_DML
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_FKEY
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_QPSG
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_TRIGGER
 -- Data: sqlite3.SQLITE_DBCONFIG_ENABLE_VIEW
 -- Data: sqlite3.SQLITE_DBCONFIG_LEGACY_ALTER_TABLE
 -- Data: sqlite3.SQLITE_DBCONFIG_LEGACY_FILE_FORMAT
 -- Data: sqlite3.SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE
 -- Data: sqlite3.SQLITE_DBCONFIG_RESET_DATABASE
 -- Data: sqlite3.SQLITE_DBCONFIG_TRIGGER_EQP
 -- Data: sqlite3.SQLITE_DBCONFIG_TRUSTED_SCHEMA
 -- Data: sqlite3.SQLITE_DBCONFIG_WRITABLE_SCHEMA

     These constants are used for the *note Connection.setconfig(): 4bd.
     and *note getconfig(): 4bc. methods.

     The availability of these constants varies depending on the version
     of SQLite Python was compiled with.

     Added in version 3.12.

     See also
     ........

     ‘https://www.sqlite.org/c3ref/c_dbconfig_defensive.html’

          SQLite docs: Database Connection Configuration Options

   ---------- Footnotes ----------

   (1) https://sqlite.org/threadsafe.html

   (2) https://peps.python.org/pep-0249/#threadsafety

   (3) https://sqlite.org/compile.html#threadsafe


File: python.info,  Node: Connection objects,  Next: Cursor objects,  Prev: Module constants,  Up: Reference

5.12.6.5 Connection objects
...........................

 -- Class: sqlite3.Connection

     Each open SQLite database is represented by a ‘Connection’ object,
     which is created using *note sqlite3.connect(): 2a8.  Their main
     purpose is creating *note Cursor: 2ab4. objects, and *note
     Transaction control: 2ab6.

     See also
     ........

        * *note How to use connection shortcut methods: 2ae8.

        * *note How to use the connection context manager: 1912.

     Changed in version 3.13: A *note ResourceWarning: 244. is emitted
     if *note close(): 246. is not called before a ‘Connection’ object
     is deleted.

     An SQLite database connection has the following attributes and
     methods:

      -- Method: cursor (factory=Cursor)

          Create and return a *note Cursor: 2ab4. object.  The cursor
          method accepts a single optional parameter 'factory'.  If
          supplied, this must be a *note callable: 2acb. returning an
          instance of ‘Cursor’ or its subclasses.

      -- Method: blobopen (table, column, rowid, /, *, readonly=False,
               name='main')

          Open a *note Blob: 685. handle to an existing BLOB (Binary
          Large OBject).


          Parameters:

             * ‘table’ (*note str: 44f.) – The name of the table where
               the blob is located.

             * ‘column’ (*note str: 44f.) – The name of the column where
               the blob is located.

             * ‘rowid’ (*note int: 257.) – The row id where the blob is
               located.

             * ‘readonly’ (*note bool: 46b.) – Set to ‘True’ if the blob
               should be opened without write permissions.  Defaults to
               ‘False’.

             * ‘name’ (*note str: 44f.) – The name of the database where
               the blob is located.  Defaults to ‘"main"’.


          Raises: *note OperationalError: 19f8. – When trying to open a
          blob in a ‘WITHOUT ROWID’ table.


          Return type: *note Blob: 685.

               Note: The blob size cannot be changed using the *note
               Blob: 685. class.  Use the SQL function ‘zeroblob’ to
               create a blob with a fixed size.

          Added in version 3.11.

      -- Method: commit ()

          Commit any pending transaction to the database.  If *note
          autocommit: 4b9. is ‘True’, or there is no open transaction,
          this method does nothing.  If ‘autocommit’ is ‘False’, a new
          transaction is implicitly opened if a pending transaction was
          committed by this method.

      -- Method: rollback ()

          Roll back to the start of any pending transaction.  If *note
          autocommit: 4b9. is ‘True’, or there is no open transaction,
          this method does nothing.  If ‘autocommit’ is ‘False’, a new
          transaction is implicitly opened if a pending transaction was
          rolled back by this method.

      -- Method: close ()

          Close the database connection.  If *note autocommit: 4b9. is
          ‘False’, any pending transaction is implicitly rolled back.
          If ‘autocommit’ is ‘True’ or *note LEGACY_TRANSACTION_CONTROL:
          2ac6, no implicit transaction control is executed.  Make sure
          to *note commit(): 2ab7. before closing to avoid losing
          pending changes.

      -- Method: execute (sql, parameters=(), /)

          Create a new *note Cursor: 2ab4. object and call *note
          execute(): 2d1. on it with the given 'sql' and 'parameters'.
          Return the new cursor object.

      -- Method: executemany (sql, parameters, /)

          Create a new *note Cursor: 2ab4. object and call *note
          executemany(): 2d2. on it with the given 'sql' and
          'parameters'.  Return the new cursor object.

      -- Method: executescript (sql_script, /)

          Create a new *note Cursor: 2ab4. object and call *note
          executescript(): 2aed. on it with the given 'sql_script'.
          Return the new cursor object.

      -- Method: create_function (name, narg, func, *,
               deterministic=False)

          Create or remove a user-defined SQL function.


          Parameters:

             * ‘name’ (*note str: 44f.) – The name of the SQL function.

             * ‘narg’ (*note int: 257.) – The number of arguments the
               SQL function can accept.  If ‘-1’, it may take any number
               of arguments.

             * ‘func’ (*note callback: 2aee. | None) – A *note callable:
               2acb. that is called when the SQL function is invoked.
               The callable must return *note a type natively supported
               by SQLite: 2ac0.  Set to ‘None’ to remove an existing SQL
               function.

             * ‘deterministic’ (*note bool: 46b.) – If ‘True’, the
               created SQL function is marked as deterministic(1), which
               allows SQLite to perform additional optimizations.

          Changed in version 3.8: Added the 'deterministic' parameter.

          Example:

               >>> import hashlib
               >>> def md5sum(t):
               ...     return hashlib.md5(t).hexdigest()
               >>> con = sqlite3.connect(":memory:")
               >>> con.create_function("md5", 1, md5sum)
               >>> for row in con.execute("SELECT md5(?)", (b"foo",)):
               ...     print(row)
               ('acbd18db4cc2f85cedef654fccc4a4d8',)
               >>> con.close()

          Changed in version 3.13: Passing 'name', 'narg', and 'func' as
          keyword arguments is deprecated.  These parameters will become
          positional-only in Python 3.15.

      -- Method: create_aggregate (name, n_arg, aggregate_class)

          Create or remove a user-defined SQL aggregate function.


          Parameters:

             * ‘name’ (*note str: 44f.) – The name of the SQL aggregate
               function.

             * ‘n_arg’ (*note int: 257.) – The number of arguments the
               SQL aggregate function can accept.  If ‘-1’, it may take
               any number of arguments.

             * ‘aggregate_class’ (*note class: 1aa4. | None) – A class
               must implement the following methods:

                  * ‘step()’: Add a row to the aggregate.

                  * ‘finalize()’: Return the final result of the
                    aggregate as *note a type natively supported by
                    SQLite: 2ac0.

               The number of arguments that the ‘step()’ method must
               accept is controlled by 'n_arg'.

               Set to ‘None’ to remove an existing SQL aggregate
               function.

          Example:

               class MySum:
                   def __init__(self):
                       self.count = 0

                   def step(self, value):
                       self.count += value

                   def finalize(self):
                       return self.count

               con = sqlite3.connect(":memory:")
               con.create_aggregate("mysum", 1, MySum)
               cur = con.execute("CREATE TABLE test(i)")
               cur.execute("INSERT INTO test(i) VALUES(1)")
               cur.execute("INSERT INTO test(i) VALUES(2)")
               cur.execute("SELECT mysum(i) FROM test")
               print(cur.fetchone()[0])

               con.close()

          Changed in version 3.13: Passing 'name', 'n_arg', and
          'aggregate_class' as keyword arguments is deprecated.  These
          parameters will become positional-only in Python 3.15.

      -- Method: create_window_function (name, num_params,
               aggregate_class, /)

          Create or remove a user-defined aggregate window function.


          Parameters:

             * ‘name’ (*note str: 44f.) – The name of the SQL aggregate
               window function to create or remove.

             * ‘num_params’ (*note int: 257.) – The number of arguments
               the SQL aggregate window function can accept.  If ‘-1’,
               it may take any number of arguments.

             * ‘aggregate_class’ (*note class: 1aa4. | None) – A class
               that must implement the following methods:

                  * ‘step()’: Add a row to the current window.

                  * ‘value()’: Return the current value of the
                    aggregate.

                  * ‘inverse()’: Remove a row from the current window.

                  * ‘finalize()’: Return the final result of the
                    aggregate as *note a type natively supported by
                    SQLite: 2ac0.

               The number of arguments that the ‘step()’ and ‘value()’
               methods must accept is controlled by 'num_params'.

               Set to ‘None’ to remove an existing SQL aggregate window
               function.


          Raises: *note NotSupportedError: 2aef. – If used with a
          version of SQLite older than 3.25.0, which does not support
          aggregate window functions.

          Added in version 3.11.

          Example:

               # Example taken from https://www.sqlite.org/windowfunctions.html#udfwinfunc
               class WindowSumInt:
                   def __init__(self):
                       self.count = 0

                   def step(self, value):
                       """Add a row to the current window."""
                       self.count += value

                   def value(self):
                       """Return the current value of the aggregate."""
                       return self.count

                   def inverse(self, value):
                       """Remove a row from the current window."""
                       self.count -= value

                   def finalize(self):
                       """Return the final value of the aggregate.

                       Any clean-up actions should be placed here.
                       """
                       return self.count


               con = sqlite3.connect(":memory:")
               cur = con.execute("CREATE TABLE test(x, y)")
               values = [
                   ("a", 4),
                   ("b", 5),
                   ("c", 3),
                   ("d", 8),
                   ("e", 1),
               ]
               cur.executemany("INSERT INTO test VALUES(?, ?)", values)
               con.create_window_function("sumint", 1, WindowSumInt)
               cur.execute("""
                   SELECT x, sumint(y) OVER (
                       ORDER BY x ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING
                   ) AS sum_y
                   FROM test ORDER BY x
               """)
               print(cur.fetchall())
               con.close()

      -- Method: create_collation (name, callable, /)

          Create a collation named 'name' using the collating function
          'callable'.  'callable' is passed two *note string: 44f.
          arguments, and it should return an *note integer: 257.:

             * ‘1’ if the first is ordered higher than the second

             * ‘-1’ if the first is ordered lower than the second

             * ‘0’ if they are ordered equal

          The following example shows a reverse sorting collation:

               def collate_reverse(string1, string2):
                   if string1 == string2:
                       return 0
                   elif string1 < string2:
                       return 1
                   else:
                       return -1

               con = sqlite3.connect(":memory:")
               con.create_collation("reverse", collate_reverse)

               cur = con.execute("CREATE TABLE test(x)")
               cur.executemany("INSERT INTO test(x) VALUES(?)", [("a",), ("b",)])
               cur.execute("SELECT x FROM test ORDER BY x COLLATE reverse")
               for row in cur:
                   print(row)
               con.close()

          Remove a collation function by setting 'callable' to ‘None’.

          Changed in version 3.11: The collation name can contain any
          Unicode character.  Earlier, only ASCII characters were
          allowed.

      -- Method: interrupt ()

          Call this method from a different thread to abort any queries
          that might be executing on the connection.  Aborted queries
          will raise an *note OperationalError: 19f8.

      -- Method: set_authorizer (authorizer_callback)

          Register *note callable: 2acb. 'authorizer_callback' to be
          invoked for each attempt to access a column of a table in the
          database.  The callback should return one of *note SQLITE_OK:
          2ace, *note SQLITE_DENY: 2acf, or *note SQLITE_IGNORE: 2ad0.
          to signal how access to the column should be handled by the
          underlying SQLite library.

          The first argument to the callback signifies what kind of
          operation is to be authorized.  The second and third argument
          will be arguments or ‘None’ depending on the first argument.
          The 4th argument is the name of the database (“main”, “temp”,
          etc.)  if applicable.  The 5th argument is the name of the
          inner-most trigger or view that is responsible for the access
          attempt or ‘None’ if this access attempt is directly from
          input SQL code.

          Please consult the SQLite documentation about the possible
          values for the first argument and the meaning of the second
          and third argument depending on the first one.  All necessary
          constants are available in the ‘sqlite3’ module.

          Passing ‘None’ as 'authorizer_callback' will disable the
          authorizer.

          Changed in version 3.11: Added support for disabling the
          authorizer using ‘None’.

          Changed in version 3.13: Passing 'authorizer_callback' as a
          keyword argument is deprecated.  The parameter will become
          positional-only in Python 3.15.

      -- Method: set_progress_handler (progress_handler, n)

          Register *note callable: 2acb. 'progress_handler' to be
          invoked for every 'n' instructions of the SQLite virtual
          machine.  This is useful if you want to get called from SQLite
          during long-running operations, for example to update a GUI.

          If you want to clear any previously installed progress
          handler, call the method with ‘None’ for 'progress_handler'.

          Returning a non-zero value from the handler function will
          terminate the currently executing query and cause it to raise
          a *note DatabaseError: 2af1. exception.

          Changed in version 3.13: Passing 'progress_handler' as a
          keyword argument is deprecated.  The parameter will become
          positional-only in Python 3.15.

      -- Method: set_trace_callback (trace_callback)

          Register *note callable: 2acb. 'trace_callback' to be invoked
          for each SQL statement that is actually executed by the SQLite
          backend.

          The only argument passed to the callback is the statement (as
          *note str: 44f.) that is being executed.  The return value of
          the callback is ignored.  Note that the backend does not only
          run statements passed to the *note Cursor.execute(): 2d1.
          methods.  Other sources include the *note transaction
          management: 2ab6. of the ‘sqlite3’ module and the execution of
          triggers defined in the current database.

          Passing ‘None’ as 'trace_callback' will disable the trace
          callback.

               Note: Exceptions raised in the trace callback are not
               propagated.  As a development and debugging aid, use
               *note enable_callback_tracebacks(): 2ac9. to enable
               printing tracebacks from exceptions raised in the trace
               callback.

          Added in version 3.3.

          Changed in version 3.13: Passing 'trace_callback' as a keyword
          argument is deprecated.  The parameter will become
          positional-only in Python 3.15.

      -- Method: enable_load_extension (enabled, /)

          Enable the SQLite engine to load SQLite extensions from shared
          libraries if 'enabled' is ‘True’; else, disallow loading
          SQLite extensions.  SQLite extensions can define new
          functions, aggregates or whole new virtual table
          implementations.  One well-known extension is the
          fulltext-search extension distributed with SQLite.

               Note: The ‘sqlite3’ module is not built with loadable
               extension support by default, because some platforms
               (notably macOS) have SQLite libraries which are compiled
               without this feature.  To get loadable extension support,
               you must pass the *note
               -enable-loadable-sqlite-extensions: 1f13. option to
               ‘configure’.

          Raises an *note auditing event: 1a15.
          ‘sqlite3.enable_load_extension’ with arguments ‘connection’,
          ‘enabled’.

          Added in version 3.2.

          Changed in version 3.10: Added the
          ‘sqlite3.enable_load_extension’ auditing event.

               con.enable_load_extension(True)

               # Load the fulltext search extension
               con.execute("select load_extension('./fts3.so')")

               # alternatively you can load the extension using an API call:
               # con.load_extension("./fts3.so")

               # disable extension loading again
               con.enable_load_extension(False)

               # example from SQLite wiki
               con.execute("CREATE VIRTUAL TABLE recipe USING fts3(name, ingredients)")
               con.executescript("""
                   INSERT INTO recipe (name, ingredients) VALUES('broccoli stew', 'broccoli peppers cheese tomatoes');
                   INSERT INTO recipe (name, ingredients) VALUES('pumpkin stew', 'pumpkin onions garlic celery');
                   INSERT INTO recipe (name, ingredients) VALUES('broccoli pie', 'broccoli cheese onions flour');
                   INSERT INTO recipe (name, ingredients) VALUES('pumpkin pie', 'pumpkin sugar flour butter');
                   """)
               for row in con.execute("SELECT rowid, name, ingredients FROM recipe WHERE name MATCH 'pie'"):
                   print(row)

      -- Method: load_extension (path, /, *, entrypoint=None)

          Load an SQLite extension from a shared library.  Enable
          extension loading with *note enable_load_extension(): 844.
          before calling this method.


          Parameters:

             * ‘path’ (*note str: 44f.) – The path to the SQLite
               extension.

             * ‘entrypoint’ (*note str: 44f.‘ | ’‘None’) – Entry point
               name.  If ‘None’ (the default), SQLite will come up with
               an entry point name of its own; see the SQLite docs
               Loading an Extension(2) for details.

          Raises an *note auditing event: 1a15. ‘sqlite3.load_extension’
          with arguments ‘connection’, ‘path’.

          Added in version 3.2.

          Changed in version 3.10: Added the ‘sqlite3.load_extension’
          auditing event.

          Changed in version 3.12: Added the 'entrypoint' parameter.

      -- Method: iterdump (*, filter=None)

          Return an *note iterator: 1ac. to dump the database as SQL
          source code.  Useful when saving an in-memory database for
          later restoration.  Similar to the ‘.dump’ command in the
          ‘sqlite3’ shell.


          Parameters: ‘filter’ (*note str: 44f.‘ | ’‘None’) – An
          optional ‘LIKE’ pattern for database objects to dump, e.g.
          ‘prefix_%’.  If ‘None’ (the default), all database objects
          will be included.

          Example:

               # Convert file example.db to SQL dump file dump.sql
               con = sqlite3.connect('example.db')
               with open('dump.sql', 'w') as f:
                   for line in con.iterdump():
                       f.write('%s\n' % line)
               con.close()

          See also
          ........

          *note How to handle non-UTF-8 text encodings: 2af2.

          Changed in version 3.13: Added the 'filter' parameter.

      -- Method: backup (target, *, pages=-1, progress=None,
               name='main', sleep=0.250)

          Create a backup of an SQLite database.

          Works even if the database is being accessed by other clients
          or concurrently by the same connection.


          Parameters:

             * ‘target’ (*note Connection: 245.) – The database
               connection to save the backup to.

             * ‘pages’ (*note int: 257.) – The number of pages to copy
               at a time.  If equal to or less than ‘0’, the entire
               database is copied in a single step.  Defaults to ‘-1’.

             * ‘progress’ (*note callback: 2aee. | None) – If set to a
               *note callable: 2acb, it is invoked with three integer
               arguments for every backup iteration: the 'status' of the
               last iteration, the 'remaining' number of pages still to
               be copied, and the 'total' number of pages.  Defaults to
               ‘None’.

             * ‘name’ (*note str: 44f.) – The name of the database to
               back up.  Either ‘"main"’ (the default) for the main
               database, ‘"temp"’ for the temporary database, or the
               name of a custom database as attached using the ‘ATTACH
               DATABASE’ SQL statement.

             * ‘sleep’ (*note float: 2f7.) – The number of seconds to
               sleep between successive attempts to back up remaining
               pages.

          Example 1, copy an existing database into another:

               def progress(status, remaining, total):
                   print(f'Copied {total-remaining} of {total} pages...')

               src = sqlite3.connect('example.db')
               dst = sqlite3.connect('backup.db')
               with dst:
                   src.backup(dst, pages=1, progress=progress)
               dst.close()
               src.close()

          Example 2, copy an existing database into a transient copy:

               src = sqlite3.connect('example.db')
               dst = sqlite3.connect(':memory:')
               src.backup(dst)
               dst.close()
               src.close()

          Added in version 3.7.

          See also
          ........

          *note How to handle non-UTF-8 text encodings: 2af2.

      -- Method: getlimit (category, /)

          Get a connection runtime limit.


          Parameters: ‘category’ (*note int: 257.) – The SQLite limit
          category(3) to be queried.


          Return type: *note int: 257.


          Raises: *note ProgrammingError: 4f5. – If 'category' is not
          recognised by the underlying SQLite library.

          Example, query the maximum length of an SQL statement for
          ‘Connection’ ‘con’ (the default is 1000000000):

               >>> con.getlimit(sqlite3.SQLITE_LIMIT_SQL_LENGTH)
               1000000000

          Added in version 3.11.

      -- Method: setlimit (category, limit, /)

          Set a connection runtime limit.  Attempts to increase a limit
          above its hard upper bound are silently truncated to the hard
          upper bound.  Regardless of whether or not the limit was
          changed, the prior value of the limit is returned.


          Parameters:

             * ‘category’ (*note int: 257.) – The SQLite limit
               category(4) to be set.

             * ‘limit’ (*note int: 257.) – The value of the new limit.
               If negative, the current limit is unchanged.


          Return type: *note int: 257.


          Raises: *note ProgrammingError: 4f5. – If 'category' is not
          recognised by the underlying SQLite library.

          Example, limit the number of attached databases to 1 for
          ‘Connection’ ‘con’ (the default limit is 10):

               >>> con.setlimit(sqlite3.SQLITE_LIMIT_ATTACHED, 1)
               10
               >>> con.getlimit(sqlite3.SQLITE_LIMIT_ATTACHED)
               1

          Added in version 3.11.

      -- Method: getconfig (op, /)

          Query a boolean connection configuration option.


          Parameters: ‘op’ (*note int: 257.) – A *note SQLITE_DBCONFIG
          code: 2ad5.


          Return type: *note bool: 46b.

          Added in version 3.12.

      -- Method: setconfig (op, enable=True, /)

          Set a boolean connection configuration option.


          Parameters:

             * ‘op’ (*note int: 257.) – A *note SQLITE_DBCONFIG code:
               2ad5.

             * ‘enable’ (*note bool: 46b.) – ‘True’ if the configuration
               option should be enabled (default); ‘False’ if it should
               be disabled.

          Added in version 3.12.

      -- Method: serialize (*, name='main')

          Serialize a database into a *note bytes: 1c2. object.  For an
          ordinary on-disk database file, the serialization is just a
          copy of the disk file.  For an in-memory database or a “temp”
          database, the serialization is the same sequence of bytes
          which would be written to disk if that database were backed up
          to disk.


          Parameters: ‘name’ (*note str: 44f.) – The database name to be
          serialized.  Defaults to ‘"main"’.


          Return type: *note bytes: 1c2.

               Note: This method is only available if the underlying
               SQLite library has the serialize API.

          Added in version 3.11.

      -- Method: deserialize (data, /, *, name='main')

          Deserialize a *note serialized: 681. database into a
          ‘Connection’.  This method causes the database connection to
          disconnect from database 'name', and reopen 'name' as an
          in-memory database based on the serialization contained in
          'data'.


          Parameters:

             * ‘data’ (*note bytes: 1c2.) – A serialized database.

             * ‘name’ (*note str: 44f.) – The database name to
               deserialize into.  Defaults to ‘"main"’.


          Raises:

             * *note OperationalError: 19f8. – If the database
               connection is currently involved in a read transaction or
               a backup operation.

             * *note DatabaseError: 2af1. – If 'data' does not contain a
               valid SQLite database.

             * *note OverflowError: 888. – If *note len(data): 631. is
               larger than ‘2**63 - 1’.

               Note: This method is only available if the underlying
               SQLite library has the deserialize API.

          Added in version 3.11.

      -- Attribute: autocommit

          This attribute controls PEP 249(5)-compliant transaction
          behaviour.  ‘autocommit’ has three allowed values:

             * ‘False’: Select PEP 249(6)-compliant transaction
               behaviour, implying that ‘sqlite3’ ensures a transaction
               is always open.  Use *note commit(): 2ab7. and *note
               rollback(): 2ae9. to close transactions.

               This is the recommended value of ‘autocommit’.

             * ‘True’: Use SQLite’s autocommit mode(7).  *note commit():
               2ab7. and *note rollback(): 2ae9. have no effect in this
               mode.

             * *note LEGACY_TRANSACTION_CONTROL: 2ac6.: Pre-Python 3.12
               (non- PEP 249(8)-compliant) transaction control.  See
               *note isolation_level: 2ac4. for more details.

               This is currently the default value of ‘autocommit’.

          Changing ‘autocommit’ to ‘False’ will open a new transaction,
          and changing it to ‘True’ will commit any pending transaction.

          See *note Transaction control via the autocommit attribute:
          4ba. for more details.

               Note: The *note isolation_level: 2ac4. attribute has no
               effect unless *note autocommit: 4b9. is *note
               LEGACY_TRANSACTION_CONTROL: 2ac6.

          Added in version 3.12.

      -- Attribute: in_transaction

          This read-only attribute corresponds to the low-level SQLite
          autocommit mode(9).

          ‘True’ if a transaction is active (there are uncommitted
          changes), ‘False’ otherwise.

          Added in version 3.2.

      -- Attribute: isolation_level

          Controls the *note legacy transaction handling mode: 2ac5. of
          ‘sqlite3’.  If set to ‘None’, transactions are never
          implicitly opened.  If set to one of ‘"DEFERRED"’,
          ‘"IMMEDIATE"’, or ‘"EXCLUSIVE"’, corresponding to the
          underlying SQLite transaction behaviour(10), *note implicit
          transaction management: 2ac5. is performed.

          If not overridden by the 'isolation_level' parameter of *note
          connect(): 2a8, the default is ‘""’, which is an alias for
          ‘"DEFERRED"’.

               Note: Using *note autocommit: 4b9. to control transaction
               handling is recommended over using ‘isolation_level’.
               ‘isolation_level’ has no effect unless ‘autocommit’ is
               set to *note LEGACY_TRANSACTION_CONTROL: 2ac6. (the
               default).

      -- Attribute: row_factory

          The initial *note row_factory: 2af4. for *note Cursor: 2ab4.
          objects created from this connection.  Assigning to this
          attribute does not affect the ‘row_factory’ of existing
          cursors belonging to this connection, only new ones.  Is
          ‘None’ by default, meaning each row is returned as a *note
          tuple: 373.

          See *note How to create and use row factories: 2abb. for more
          details.

      -- Attribute: text_factory

          A *note callable: 2acb. that accepts a *note bytes: 1c2.
          parameter and returns a text representation of it.  The
          callable is invoked for SQLite values with the ‘TEXT’ data
          type.  By default, this attribute is set to *note str: 44f.

          See *note How to handle non-UTF-8 text encodings: 2af2. for
          more details.

      -- Attribute: total_changes

          Return the total number of database rows that have been
          modified, inserted, or deleted since the database connection
          was opened.

   ---------- Footnotes ----------

   (1) https://sqlite.org/deterministic.html

   (2) https://www.sqlite.org/loadext.html#loading_an_extension

   (3) https://www.sqlite.org/c3ref/c_limit_attached.html

   (4) https://www.sqlite.org/c3ref/c_limit_attached.html

   (5) https://peps.python.org/pep-0249/

   (6) https://peps.python.org/pep-0249/

   (7) 
https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions

   (8) https://peps.python.org/pep-0249/

   (9) 
https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions

   (10) 
https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions


File: python.info,  Node: Cursor objects,  Next: Row objects,  Prev: Connection objects,  Up: Reference

5.12.6.6 Cursor objects
.......................

     A ‘Cursor’ object represents a database cursor(1) which is used to
     execute SQL statements, and manage the context of a fetch
     operation.  Cursors are created using *note Connection.cursor():
     2ab3, or by using any of the *note connection shortcut methods:
     2ae8.

     Cursor objects are *note iterators: 1ac, meaning that if you *note
     execute(): 2d1. a ‘SELECT’ query, you can simply iterate over the
     cursor to fetch the resulting rows:

          for row in cur.execute("SELECT t FROM data"):
              print(row)

 -- Class: sqlite3.Cursor

     A ‘Cursor’ instance has the following attributes and methods.

      -- Method: execute (sql, parameters=(), /)

          Execute a single SQL statement, optionally binding Python
          values using *note placeholders: 2d3.


          Parameters:

             * ‘sql’ (*note str: 44f.) – A single SQL statement.

             * ‘parameters’ (*note dict: 256. | *note sequence: 4f4.) –
               Python values to bind to placeholders in 'sql'.  A ‘dict’
               if named placeholders are used.  A sequence if unnamed
               placeholders are used.  See *note How to use placeholders
               to bind values in SQL queries: 2d3.


          Raises: *note ProgrammingError: 4f5. – If 'sql' contains more
          than one SQL statement.

          If *note autocommit: 4b9. is *note LEGACY_TRANSACTION_CONTROL:
          2ac6, *note isolation_level: 2ac4. is not ‘None’, 'sql' is an
          ‘INSERT’, ‘UPDATE’, ‘DELETE’, or ‘REPLACE’ statement, and
          there is no open transaction, a transaction is implicitly
          opened before executing 'sql'.

          Deprecated since version 3.12, will be removed in version
          3.14: *note DeprecationWarning: 1a5. is emitted if *note named
          placeholders: 2d3. are used and 'parameters' is a sequence
          instead of a *note dict: 256.  Starting with Python 3.14,
          *note ProgrammingError: 4f5. will be raised instead.

          Use *note executescript(): 2aed. to execute multiple SQL
          statements.

      -- Method: executemany (sql, parameters, /)

          For every item in 'parameters', repeatedly execute the *note
          parameterized: 2d3. DML (Data Manipulation Language) SQL
          statement 'sql'.

          Uses the same implicit transaction handling as *note
          execute(): 2d1.


          Parameters:

             * ‘sql’ (*note str: 44f.) – A single SQL DML statement.

             * ‘parameters’ (*note iterable: 126d.) – An iterable of
               parameters to bind with the placeholders in 'sql'.  See
               *note How to use placeholders to bind values in SQL
               queries: 2d3.


          Raises: *note ProgrammingError: 4f5. – If 'sql' contains more
          than one SQL statement, or is not a DML statement.

          Example:

               rows = [
                   ("row1",),
                   ("row2",),
               ]
               # cur is an sqlite3.Cursor object
               cur.executemany("INSERT INTO data VALUES(?)", rows)

               Note: Any resulting rows are discarded, including DML
               statements with RETURNING clauses(2).

          Deprecated since version 3.12, will be removed in version
          3.14: *note DeprecationWarning: 1a5. is emitted if *note named
          placeholders: 2d3. are used and the items in 'parameters' are
          sequences instead of *note dict: 256.s.  Starting with Python
          3.14, *note ProgrammingError: 4f5. will be raised instead.

      -- Method: executescript (sql_script, /)

          Execute the SQL statements in 'sql_script'.  If the *note
          autocommit: 4b9. is *note LEGACY_TRANSACTION_CONTROL: 2ac6.
          and there is a pending transaction, an implicit ‘COMMIT’
          statement is executed first.  No other implicit transaction
          control is performed; any transaction control must be added to
          'sql_script'.

          'sql_script' must be a *note string: 44f.

          Example:

               # cur is an sqlite3.Cursor object
               cur.executescript("""
                   BEGIN;
                   CREATE TABLE person(firstname, lastname, age);
                   CREATE TABLE book(title, author, published);
                   CREATE TABLE publisher(name, address);
                   COMMIT;
               """)

      -- Method: fetchone ()

          If *note row_factory: 2af4. is ‘None’, return the next row
          query result set as a *note tuple: 373.  Else, pass it to the
          row factory and return its result.  Return ‘None’ if no more
          data is available.

      -- Method: fetchmany (size=cursor.arraysize)

          Return the next set of rows of a query result as a *note list:
          614.  Return an empty list if no more rows are available.

          The number of rows to fetch per call is specified by the
          'size' parameter.  If 'size' is not given, *note arraysize:
          1612. determines the number of rows to be fetched.  If fewer
          than 'size' rows are available, as many rows as are available
          are returned.

          Note there are performance considerations involved with the
          'size' parameter.  For optimal performance, it is usually best
          to use the arraysize attribute.  If the 'size' parameter is
          used, then it is best for it to retain the same value from one
          ‘fetchmany()’ call to the next.

          Changed in version 3.13.8: Negative 'size' values are rejected
          by raising *note ValueError: 202.

      -- Method: fetchall ()

          Return all (remaining) rows of a query result as a *note list:
          614.  Return an empty list if no rows are available.  Note
          that the *note arraysize: 1612. attribute can affect the
          performance of this operation.

      -- Method: close ()

          Close the cursor now (rather than whenever ‘__del__’ is
          called).

          The cursor will be unusable from this point forward; a *note
          ProgrammingError: 4f5. exception will be raised if any
          operation is attempted with the cursor.

      -- Method: setinputsizes (sizes, /)

          Required by the DB-API. Does nothing in ‘sqlite3’.

      -- Method: setoutputsize (size, column=None, /)

          Required by the DB-API. Does nothing in ‘sqlite3’.

      -- Attribute: arraysize

          Read/write attribute that controls the number of rows returned
          by *note fetchmany(): 1611.  The default value is 1 which
          means a single row would be fetched per call.

          Changed in version 3.13.8: Negative values are rejected by
          raising *note ValueError: 202.

      -- Attribute: connection

          Read-only attribute that provides the SQLite database *note
          Connection: 245. belonging to the cursor.  A ‘Cursor’ object
          created by calling *note con.cursor(): 2ab3. will have a *note
          connection: 2afc. attribute that refers to 'con':

               >>> con = sqlite3.connect(":memory:")
               >>> cur = con.cursor()
               >>> cur.connection == con
               True
               >>> con.close()

      -- Attribute: description

          Read-only attribute that provides the column names of the last
          query.  To remain compatible with the Python DB API, it
          returns a 7-tuple for each column where the last six items of
          each tuple are ‘None’.

          It is set for ‘SELECT’ statements without any matching rows as
          well.

      -- Attribute: lastrowid

          Read-only attribute that provides the row id of the last
          inserted row.  It is only updated after successful ‘INSERT’ or
          ‘REPLACE’ statements using the *note execute(): 2d1. method.
          For other statements, after *note executemany(): 2d2. or *note
          executescript(): 2aed, or if the insertion failed, the value
          of ‘lastrowid’ is left unchanged.  The initial value of
          ‘lastrowid’ is ‘None’.

               Note: Inserts into ‘WITHOUT ROWID’ tables are not
               recorded.

          Changed in version 3.6: Added support for the ‘REPLACE’
          statement.

      -- Attribute: rowcount

          Read-only attribute that provides the number of modified rows
          for ‘INSERT’, ‘UPDATE’, ‘DELETE’, and ‘REPLACE’ statements; is
          ‘-1’ for other statements, including CTE (Common Table
          Expression) queries.  It is only updated by the *note
          execute(): 2d1. and *note executemany(): 2d2. methods, after
          the statement has run to completion.  This means that any
          resulting rows must be fetched in order for ‘rowcount’ to be
          updated.

      -- Attribute: row_factory

          Control how a row fetched from this ‘Cursor’ is represented.
          If ‘None’, a row is represented as a *note tuple: 373.  Can be
          set to the included *note sqlite3.Row: ea5.; or a *note
          callable: 2acb. that accepts two arguments, a ‘Cursor’ object
          and the ‘tuple’ of row values, and returns a custom object
          representing an SQLite row.

          Defaults to what *note Connection.row_factory: 1737. was set
          to when the ‘Cursor’ was created.  Assigning to this attribute
          does not affect ‘Connection.row_factory’ of the parent
          connection.

          See *note How to create and use row factories: 2abb. for more
          details.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Cursor_(databases)

   (2) https://www.sqlite.org/lang_returning.html


File: python.info,  Node: Row objects,  Next: Blob objects,  Prev: Cursor objects,  Up: Reference

5.12.6.7 Row objects
....................

 -- Class: sqlite3.Row

     A ‘Row’ instance serves as a highly optimized *note row_factory:
     1737. for *note Connection: 245. objects.  It supports iteration,
     equality testing, *note len(): 631, and *note mapping: 1200. access
     by column name and index.

     Two ‘Row’ objects compare equal if they have identical column names
     and values.

     See *note How to create and use row factories: 2abb. for more
     details.

      -- Method: keys ()

          Return a *note list: 614. of column names as *note strings:
          44f.  Immediately after a query, it is the first member of
          each tuple in *note Cursor.description: 1668.

     Changed in version 3.5: Added support of slicing.


File: python.info,  Node: Blob objects,  Next: PrepareProtocol objects,  Prev: Row objects,  Up: Reference

5.12.6.8 Blob objects
.....................

 -- Class: sqlite3.Blob

     Added in version 3.11.

     A ‘Blob’ instance is a *note file-like object: 15f4. that can read
     and write data in an SQLite BLOB.  Call *note len(blob): 631. to
     get the size (number of bytes) of the blob.  Use indices and *note
     slices: 2336. for direct access to the blob data.

     Use the ‘Blob’ as a *note context manager: 5d7. to ensure that the
     blob handle is closed after use.

          con = sqlite3.connect(":memory:")
          con.execute("CREATE TABLE test(blob_col blob)")
          con.execute("INSERT INTO test(blob_col) VALUES(zeroblob(13))")

          # Write to our blob, using two write operations:
          with con.blobopen("test", "blob_col", 1) as blob:
              blob.write(b"hello, ")
              blob.write(b"world.")
              # Modify the first and last bytes of our blob
              blob[0] = ord("H")
              blob[-1] = ord("!")

          # Read the contents of our blob
          with con.blobopen("test", "blob_col", 1) as blob:
              greeting = blob.read()

          print(greeting)  # outputs "b'Hello, world!'"
          con.close()

      -- Method: close ()

          Close the blob.

          The blob will be unusable from this point onward.  An *note
          Error: 19c9. (or subclass) exception will be raised if any
          further operation is attempted with the blob.

      -- Method: read (length=-1, /)

          Read 'length' bytes of data from the blob at the current
          offset position.  If the end of the blob is reached, the data
          up to EOF (End of File) will be returned.  When 'length' is
          not specified, or is negative, ‘read()’ will read until the
          end of the blob.

      -- Method: write (data, /)

          Write 'data' to the blob at the current offset.  This function
          cannot change the blob length.  Writing beyond the end of the
          blob will raise *note ValueError: 202.

      -- Method: tell ()

          Return the current access position of the blob.

      -- Method: seek (offset, origin=os.SEEK_SET, /)

          Set the current access position of the blob to 'offset'.  The
          'origin' argument defaults to *note os.SEEK_SET: 12d4.
          (absolute blob positioning).  Other values for 'origin' are
          *note os.SEEK_CUR: 12d5. (seek relative to the current
          position) and *note os.SEEK_END: 12d6. (seek relative to the
          blob’s end).


File: python.info,  Node: PrepareProtocol objects,  Next: Exceptions<7>,  Prev: Blob objects,  Up: Reference

5.12.6.9 PrepareProtocol objects
................................

 -- Class: sqlite3.PrepareProtocol

     The PrepareProtocol type’s single purpose is to act as a PEP 246(1)
     style adaption protocol for objects that can *note adapt
     themselves: 2b09. to *note native SQLite types: 2ac0.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0246/


File: python.info,  Node: Exceptions<7>,  Next: SQLite and Python types,  Prev: PrepareProtocol objects,  Up: Reference

5.12.6.10 Exceptions
....................

The exception hierarchy is defined by the DB-API 2.0 ( PEP 249(1)).

 -- Exception: sqlite3.Warning

     This exception is not currently raised by the ‘sqlite3’ module, but
     may be raised by applications using ‘sqlite3’, for example if a
     user-defined function truncates data while inserting.  ‘Warning’ is
     a subclass of *note Exception: 9e5.

 -- Exception: sqlite3.Error

     The base class of the other exceptions in this module.  Use this to
     catch all errors with one single *note except: 18b. statement.
     ‘Error’ is a subclass of *note Exception: 9e5.

     If the exception originated from within the SQLite library, the
     following two attributes are added to the exception:

      -- Attribute: sqlite_errorcode

          The numeric error code from the SQLite API(2)

          Added in version 3.11.

      -- Attribute: sqlite_errorname

          The symbolic name of the numeric error code from the SQLite
          API(3)

          Added in version 3.11.

 -- Exception: sqlite3.InterfaceError

     Exception raised for misuse of the low-level SQLite C API. In other
     words, if this exception is raised, it probably indicates a bug in
     the ‘sqlite3’ module.  ‘InterfaceError’ is a subclass of *note
     Error: 19c9.

 -- Exception: sqlite3.DatabaseError

     Exception raised for errors that are related to the database.  This
     serves as the base exception for several types of database errors.
     It is only raised implicitly through the specialised subclasses.
     ‘DatabaseError’ is a subclass of *note Error: 19c9.

 -- Exception: sqlite3.DataError

     Exception raised for errors caused by problems with the processed
     data, like numeric values out of range, and strings which are too
     long.  ‘DataError’ is a subclass of *note DatabaseError: 2af1.

 -- Exception: sqlite3.OperationalError

     Exception raised for errors that are related to the database’s
     operation, and not necessarily under the control of the programmer.
     For example, the database path is not found, or a transaction could
     not be processed.  ‘OperationalError’ is a subclass of *note
     DatabaseError: 2af1.

 -- Exception: sqlite3.IntegrityError

     Exception raised when the relational integrity of the database is
     affected, e.g.  a foreign key check fails.  It is a subclass of
     *note DatabaseError: 2af1.

 -- Exception: sqlite3.InternalError

     Exception raised when SQLite encounters an internal error.  If this
     is raised, it may indicate that there is a problem with the runtime
     SQLite library.  ‘InternalError’ is a subclass of *note
     DatabaseError: 2af1.

 -- Exception: sqlite3.ProgrammingError

     Exception raised for ‘sqlite3’ API programming errors, for example
     supplying the wrong number of bindings to a query, or trying to
     operate on a closed *note Connection: 245.  ‘ProgrammingError’ is a
     subclass of *note DatabaseError: 2af1.

 -- Exception: sqlite3.NotSupportedError

     Exception raised in case a method or database API is not supported
     by the underlying SQLite library.  For example, setting
     'deterministic' to ‘True’ in *note create_function(): 2a9, if the
     underlying SQLite library does not support deterministic functions.
     ‘NotSupportedError’ is a subclass of *note DatabaseError: 2af1.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0249/

   (2) https://sqlite.org/rescode.html

   (3) https://sqlite.org/rescode.html


File: python.info,  Node: SQLite and Python types,  Next: Default adapters and converters deprecated,  Prev: Exceptions<7>,  Up: Reference

5.12.6.11 SQLite and Python types
.................................

SQLite natively supports the following types: ‘NULL’, ‘INTEGER’, ‘REAL’,
‘TEXT’, ‘BLOB’.

The following Python types can thus be sent to SQLite without any
problem:

Python type                         SQLite type
                                    
------------------------------------------------------
                                    
‘None’                              ‘NULL’
                                    
                                    
*note int: 257.                     ‘INTEGER’
                                    
                                    
*note float: 2f7.                   ‘REAL’
                                    
                                    
*note str: 44f.                     ‘TEXT’
                                    
                                    
*note bytes: 1c2.                   ‘BLOB’
                                    

This is how SQLite types are converted to Python types by default:

SQLite type       Python type
                  
---------------------------------------------------------------------
                  
‘NULL’            ‘None’
                  
                  
‘INTEGER’         *note int: 257.
                  
                  
‘REAL’            *note float: 2f7.
                  
                  
‘TEXT’            depends on *note text_factory: 2af5,
                  *note str: 44f. by default
                  
                  
‘BLOB’            *note bytes: 1c2.
                  

The type system of the ‘sqlite3’ module is extensible in two ways: you
can store additional Python types in an SQLite database via *note object
adapters: 2ab9, and you can let the ‘sqlite3’ module convert SQLite
types to Python types via *note converters: 2aba.


File: python.info,  Node: Default adapters and converters deprecated,  Next: Command-line interface,  Prev: SQLite and Python types,  Up: Reference

5.12.6.12 Default adapters and converters (deprecated)
......................................................

     Note: The default adapters and converters are deprecated as of
     Python 3.12.  Instead, use the *note Adapter and converter recipes:
     4f3. and tailor them to your needs.

The deprecated default adapters and converters consist of:

   * An adapter for *note datetime.date: 1cd. objects to *note strings:
     44f. in ISO 8601(1) format.

   * An adapter for *note datetime.datetime: 1cc. objects to strings in
     ISO 8601 format.

   * A converter for *note declared: 2aba. “date” types to *note
     datetime.date: 1cd. objects.

   * A converter for declared “timestamp” types to *note
     datetime.datetime: 1cc. objects.  Fractional parts will be
     truncated to 6 digits (microsecond precision).

     Note: The default “timestamp” converter ignores UTC offsets in the
     database and always returns a naive *note datetime.datetime: 1cc.
     object.  To preserve UTC offsets in timestamps, either leave
     converters disabled, or register an offset-aware converter with
     *note register_converter(): 2ac1.

Deprecated since version 3.12.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/ISO_8601


File: python.info,  Node: Command-line interface,  Prev: Default adapters and converters deprecated,  Up: Reference

5.12.6.13 Command-line interface
................................

The ‘sqlite3’ module can be invoked as a script, using the interpreter’s
*note -m: 5e4. switch, in order to provide a simple SQLite shell.  The
argument signature is as follows:

     python -m sqlite3 [-h] [-v] [filename] [sql]

Type ‘.quit’ or CTRL-D to exit the shell.

 -- Option: -h, --help

     Print CLI help.

 -- Option: -v, --version

     Print underlying SQLite library version.

Added in version 3.12.


File: python.info,  Node: How-to guides,  Next: Explanation,  Prev: Reference,  Up: sqlite3 — DB-API 2 0 interface for SQLite databases

5.12.6.14 How-to guides
.......................

* Menu:

* How to use placeholders to bind values in SQL queries::
* How to adapt custom Python types to SQLite values::
* How to convert SQLite values to custom Python types::
* Adapter and converter recipes::
* How to use connection shortcut methods::
* How to use the connection context manager::
* How to work with SQLite URIs::
* How to create and use row factories::
* How to handle non-UTF-8 text encodings::


File: python.info,  Node: How to use placeholders to bind values in SQL queries,  Next: How to adapt custom Python types to SQLite values,  Up: How-to guides

5.12.6.15 How to use placeholders to bind values in SQL queries
...............................................................

SQL operations usually need to use values from Python variables.
However, beware of using Python’s string operations to assemble queries,
as they are vulnerable to SQL injection attacks(1).  For example, an
attacker can simply close the single quote and inject ‘OR TRUE’ to
select all rows:

     >>> # Never do this -- insecure!
     >>> symbol = input()
     ' OR TRUE; --
     >>> sql = "SELECT * FROM stocks WHERE symbol = '%s'" % symbol
     >>> print(sql)
     SELECT * FROM stocks WHERE symbol = '' OR TRUE; --'
     >>> cur.execute(sql)

Instead, use the DB-API’s parameter substitution.  To insert a variable
into a query string, use a placeholder in the string, and substitute the
actual values into the query by providing them as a *note tuple: 373. of
values to the second argument of the cursor’s *note execute(): 2d1.
method.

An SQL statement may use one of two kinds of placeholders: question
marks (qmark style) or named placeholders (named style).  For the qmark
style, 'parameters' must be a *note sequence: 4f4. whose length must
match the number of placeholders, or a *note ProgrammingError: 4f5. is
raised.  For the named style, 'parameters' must be an instance of a
*note dict: 256. (or a subclass), which must contain keys for all named
parameters; any extra items are ignored.  Here’s an example of both
styles:

     con = sqlite3.connect(":memory:")
     cur = con.execute("CREATE TABLE lang(name, first_appeared)")

     # This is the named style used with executemany():
     data = (
         {"name": "C", "year": 1972},
         {"name": "Fortran", "year": 1957},
         {"name": "Python", "year": 1991},
         {"name": "Go", "year": 2009},
     )
     cur.executemany("INSERT INTO lang VALUES(:name, :year)", data)

     # This is the qmark style used in a SELECT query:
     params = (1972,)
     cur.execute("SELECT * FROM lang WHERE first_appeared = ?", params)
     print(cur.fetchall())
     con.close()

     Note: PEP 249(2) numeric placeholders are 'not' supported.  If
     used, they will be interpreted as named placeholders.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/SQL_injection

   (2) https://peps.python.org/pep-0249/


File: python.info,  Node: How to adapt custom Python types to SQLite values,  Next: How to convert SQLite values to custom Python types,  Prev: How to use placeholders to bind values in SQL queries,  Up: How-to guides

5.12.6.16 How to adapt custom Python types to SQLite values
...........................................................

SQLite supports only a limited set of data types natively.  To store
custom Python types in SQLite databases, 'adapt' them to one of the
*note Python types SQLite natively understands: 2ac0.

There are two ways to adapt Python objects to SQLite types: letting your
object adapt itself, or using an 'adapter callable'.  The latter will
take precedence above the former.  For a library that exports a custom
type, it may make sense to enable that type to adapt itself.  As an
application developer, it may make more sense to take direct control by
registering custom adapter functions.

* Menu:

* How to write adaptable objects::
* How to register adapter callables::


File: python.info,  Node: How to write adaptable objects,  Next: How to register adapter callables,  Up: How to adapt custom Python types to SQLite values

5.12.6.17 How to write adaptable objects
........................................

Suppose we have a ‘Point’ class that represents a pair of coordinates,
‘x’ and ‘y’, in a Cartesian coordinate system.  The coordinate pair will
be stored as a text string in the database, using a semicolon to
separate the coordinates.  This can be implemented by adding a
‘__conform__(self, protocol)’ method which returns the adapted value.
The object passed to 'protocol' will be of type *note PrepareProtocol:
1911.

     class Point:
         def __init__(self, x, y):
             self.x, self.y = x, y

         def __conform__(self, protocol):
             if protocol is sqlite3.PrepareProtocol:
                 return f"{self.x};{self.y}"

     con = sqlite3.connect(":memory:")
     cur = con.cursor()

     cur.execute("SELECT ?", (Point(4.0, -3.2),))
     print(cur.fetchone()[0])
     con.close()


File: python.info,  Node: How to register adapter callables,  Prev: How to write adaptable objects,  Up: How to adapt custom Python types to SQLite values

5.12.6.18 How to register adapter callables
...........................................

The other possibility is to create a function that converts the Python
object to an SQLite-compatible type.  This function can then be
registered using *note register_adapter(): 2aca.

     class Point:
         def __init__(self, x, y):
             self.x, self.y = x, y

     def adapt_point(point):
         return f"{point.x};{point.y}"

     sqlite3.register_adapter(Point, adapt_point)

     con = sqlite3.connect(":memory:")
     cur = con.cursor()

     cur.execute("SELECT ?", (Point(1.0, 2.5),))
     print(cur.fetchone()[0])
     con.close()


File: python.info,  Node: How to convert SQLite values to custom Python types,  Next: Adapter and converter recipes,  Prev: How to adapt custom Python types to SQLite values,  Up: How-to guides

5.12.6.19 How to convert SQLite values to custom Python types
.............................................................

Writing an adapter lets you convert 'from' custom Python types 'to'
SQLite values.  To be able to convert 'from' SQLite values 'to' custom
Python types, we use 'converters'.

Let’s go back to the ‘Point’ class.  We stored the x and y coordinates
separated via semicolons as strings in SQLite.

First, we’ll define a converter function that accepts the string as a
parameter and constructs a ‘Point’ object from it.

     Note: Converter functions are 'always' passed a *note bytes: 1c2.
     object, no matter the underlying SQLite data type.

     def convert_point(s):
         x, y = map(float, s.split(b";"))
         return Point(x, y)

We now need to tell ‘sqlite3’ when it should convert a given SQLite
value.  This is done when connecting to a database, using the
'detect_types' parameter of *note connect(): 2a8.  There are three
options:

   * Implicit: set 'detect_types' to *note PARSE_DECLTYPES: 2ac2.

   * Explicit: set 'detect_types' to *note PARSE_COLNAMES: 2ac3.

   * Both: set 'detect_types' to ‘sqlite3.PARSE_DECLTYPES |
     sqlite3.PARSE_COLNAMES’.  Column names take precedence over
     declared types.

The following example illustrates the implicit and explicit approaches:

     class Point:
         def __init__(self, x, y):
             self.x, self.y = x, y

         def __repr__(self):
             return f"Point({self.x}, {self.y})"

     def adapt_point(point):
         return f"{point.x};{point.y}"

     def convert_point(s):
         x, y = list(map(float, s.split(b";")))
         return Point(x, y)

     # Register the adapter and converter
     sqlite3.register_adapter(Point, adapt_point)
     sqlite3.register_converter("point", convert_point)

     # 1) Parse using declared types
     p = Point(4.0, -3.2)
     con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_DECLTYPES)
     cur = con.execute("CREATE TABLE test(p point)")

     cur.execute("INSERT INTO test(p) VALUES(?)", (p,))
     cur.execute("SELECT p FROM test")
     print("with declared types:", cur.fetchone()[0])
     cur.close()
     con.close()

     # 2) Parse using column names
     con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_COLNAMES)
     cur = con.execute("CREATE TABLE test(p)")

     cur.execute("INSERT INTO test(p) VALUES(?)", (p,))
     cur.execute('SELECT p AS "p [point]" FROM test')
     print("with column names:", cur.fetchone()[0])
     cur.close()
     con.close()


File: python.info,  Node: Adapter and converter recipes,  Next: How to use connection shortcut methods,  Prev: How to convert SQLite values to custom Python types,  Up: How-to guides

5.12.6.20 Adapter and converter recipes
.......................................

This section shows recipes for common adapters and converters.

     import datetime as dt
     import sqlite3

     def adapt_date_iso(val):
         """Adapt datetime.date to ISO 8601 date."""
         return val.isoformat()

     def adapt_datetime_iso(val):
         """Adapt datetime.datetime to timezone-naive ISO 8601 date."""
         return val.replace(tzinfo=None).isoformat()

     def adapt_datetime_epoch(val):
         """Adapt datetime.datetime to Unix timestamp."""
         return int(val.timestamp())

     sqlite3.register_adapter(dt.date, adapt_date_iso)
     sqlite3.register_adapter(dt.datetime, adapt_datetime_iso)
     sqlite3.register_adapter(dt.datetime, adapt_datetime_epoch)

     def convert_date(val):
         """Convert ISO 8601 date to datetime.date object."""
         return dt.date.fromisoformat(val.decode())

     def convert_datetime(val):
         """Convert ISO 8601 datetime to datetime.datetime object."""
         return dt.datetime.fromisoformat(val.decode())

     def convert_timestamp(val):
         """Convert Unix epoch timestamp to datetime.datetime object."""
         return dt.datetime.fromtimestamp(int(val))

     sqlite3.register_converter("date", convert_date)
     sqlite3.register_converter("datetime", convert_datetime)
     sqlite3.register_converter("timestamp", convert_timestamp)


File: python.info,  Node: How to use connection shortcut methods,  Next: How to use the connection context manager,  Prev: Adapter and converter recipes,  Up: How-to guides

5.12.6.21 How to use connection shortcut methods
................................................

Using the *note execute(): 2aea, *note executemany(): 2aeb, and *note
executescript(): 2aec. methods of the *note Connection: 245. class, your
code can be written more concisely because you don’t have to create the
(often superfluous) *note Cursor: 2ab4. objects explicitly.  Instead,
the ‘Cursor’ objects are created implicitly and these shortcut methods
return the cursor objects.  This way, you can execute a ‘SELECT’
statement and iterate over it directly using only a single call on the
‘Connection’ object.

     # Create and fill the table.
     con = sqlite3.connect(":memory:")
     con.execute("CREATE TABLE lang(name, first_appeared)")
     data = [
         ("C++", 1985),
         ("Objective-C", 1984),
     ]
     con.executemany("INSERT INTO lang(name, first_appeared) VALUES(?, ?)", data)

     # Print the table contents
     for row in con.execute("SELECT name, first_appeared FROM lang"):
         print(row)

     print("I just deleted", con.execute("DELETE FROM lang").rowcount, "rows")

     # close() is not a shortcut method and it's not called automatically;
     # the connection object should be closed manually
     con.close()


File: python.info,  Node: How to use the connection context manager,  Next: How to work with SQLite URIs,  Prev: How to use connection shortcut methods,  Up: How-to guides

5.12.6.22 How to use the connection context manager
...................................................

A *note Connection: 245. object can be used as a context manager that
automatically commits or rolls back open transactions when leaving the
body of the context manager.  If the body of the *note with: 5d5.
statement finishes without exceptions, the transaction is committed.  If
this commit fails, or if the body of the ‘with’ statement raises an
uncaught exception, the transaction is rolled back.  If *note
autocommit: 4b9. is ‘False’, a new transaction is implicitly opened
after committing or rolling back.

If there is no open transaction upon leaving the body of the ‘with’
statement, or if *note autocommit: 4b9. is ‘True’, the context manager
does nothing.

     Note: The context manager neither implicitly opens a new
     transaction nor closes the connection.  If you need a closing
     context manager, consider using *note contextlib.closing(): 13d6.

     con = sqlite3.connect(":memory:")
     con.execute("CREATE TABLE lang(id INTEGER PRIMARY KEY, name VARCHAR UNIQUE)")

     # Successful, con.commit() is called automatically afterwards
     with con:
         con.execute("INSERT INTO lang(name) VALUES(?)", ("Python",))

     # con.rollback() is called after the with block finishes with an exception,
     # the exception is still raised and must be caught
     try:
         with con:
             con.execute("INSERT INTO lang(name) VALUES(?)", ("Python",))
     except sqlite3.IntegrityError:
         print("couldn't add Python twice")

     # Connection object used as context manager only commits or rollbacks transactions,
     # so the connection object should be closed manually
     con.close()


File: python.info,  Node: How to work with SQLite URIs,  Next: How to create and use row factories,  Prev: How to use the connection context manager,  Up: How-to guides

5.12.6.23 How to work with SQLite URIs
......................................

Some useful URI tricks include:

   * Open a database in read-only mode:

     >>> con = sqlite3.connect("file:tutorial.db?mode=ro", uri=True)
     >>> con.execute("CREATE TABLE readonly(data)")
     Traceback (most recent call last):
     OperationalError: attempt to write a readonly database
     >>> con.close()

   * Do not implicitly create a new database file if it does not already
     exist; will raise *note OperationalError: 19f8. if unable to create
     a new file:

     >>> con = sqlite3.connect("file:nosuchdb.db?mode=rw", uri=True)
     Traceback (most recent call last):
     OperationalError: unable to open database file

   * Create a shared named in-memory database:

     db = "file:mem1?mode=memory&cache=shared"
     con1 = sqlite3.connect(db, uri=True)
     con2 = sqlite3.connect(db, uri=True)
     with con1:
         con1.execute("CREATE TABLE shared(data)")
         con1.execute("INSERT INTO shared VALUES(28)")
     res = con2.execute("SELECT data FROM shared")
     assert res.fetchone() == (28,)

     con1.close()
     con2.close()

More information about this feature, including a list of parameters, can
be found in the SQLite URI documentation(1).

   ---------- Footnotes ----------

   (1) https://www.sqlite.org/uri.html


File: python.info,  Node: How to create and use row factories,  Next: How to handle non-UTF-8 text encodings,  Prev: How to work with SQLite URIs,  Up: How-to guides

5.12.6.24 How to create and use row factories
.............................................

By default, ‘sqlite3’ represents each row as a *note tuple: 373.  If a
‘tuple’ does not suit your needs, you can use the *note sqlite3.Row:
ea5. class or a custom *note row_factory: 2af4.

While ‘row_factory’ exists as an attribute both on the *note Cursor:
2ab4. and the *note Connection: 245, it is recommended to set *note
Connection.row_factory: 1737, so all cursors created from the connection
will use the same row factory.

‘Row’ provides indexed and case-insensitive named access to columns,
with minimal memory overhead and performance impact over a ‘tuple’.  To
use ‘Row’ as a row factory, assign it to the ‘row_factory’ attribute:

     >>> con = sqlite3.connect(":memory:")
     >>> con.row_factory = sqlite3.Row

Queries now return ‘Row’ objects:

     >>> res = con.execute("SELECT 'Earth' AS name, 6378 AS radius")
     >>> row = res.fetchone()
     >>> row.keys()
     ['name', 'radius']
     >>> row[0]         # Access by index.
     'Earth'
     >>> row["name"]    # Access by name.
     'Earth'
     >>> row["RADIUS"]  # Column names are case-insensitive.
     6378
     >>> con.close()

     Note: The ‘FROM’ clause can be omitted in the ‘SELECT’ statement,
     as in the above example.  In such cases, SQLite returns a single
     row with columns defined by expressions, e.g.  literals, with the
     given aliases ‘expr AS alias’.

You can create a custom *note row_factory: 2af4. that returns each row
as a *note dict: 256, with column names mapped to values:

     def dict_factory(cursor, row):
         fields = [column[0] for column in cursor.description]
         return {key: value for key, value in zip(fields, row)}

Using it, queries now return a ‘dict’ instead of a ‘tuple’:

     >>> con = sqlite3.connect(":memory:")
     >>> con.row_factory = dict_factory
     >>> for row in con.execute("SELECT 1 AS a, 2 AS b"):
     ...     print(row)
     {'a': 1, 'b': 2}
     >>> con.close()

The following row factory returns a *note named tuple: 651.:

     from collections import namedtuple

     def namedtuple_factory(cursor, row):
         fields = [column[0] for column in cursor.description]
         cls = namedtuple("Row", fields)
         return cls._make(row)

‘namedtuple_factory()’ can be used as follows:

     >>> con = sqlite3.connect(":memory:")
     >>> con.row_factory = namedtuple_factory
     >>> cur = con.execute("SELECT 1 AS a, 2 AS b")
     >>> row = cur.fetchone()
     >>> row
     Row(a=1, b=2)
     >>> row[0]  # Indexed access.
     1
     >>> row.b   # Attribute access.
     2
     >>> con.close()

With some adjustments, the above recipe can be adapted to use a *note
dataclass: 1cb, or any other custom class, instead of a *note
namedtuple: 1ca.


File: python.info,  Node: How to handle non-UTF-8 text encodings,  Prev: How to create and use row factories,  Up: How-to guides

5.12.6.25 How to handle non-UTF-8 text encodings
................................................

By default, ‘sqlite3’ uses *note str: 44f. to adapt SQLite values with
the ‘TEXT’ data type.  This works well for UTF-8 encoded text, but it
might fail for other encodings and invalid UTF-8.  You can use a custom
*note text_factory: 2af5. to handle such cases.

Because of SQLite’s flexible typing(1), it is not uncommon to encounter
table columns with the ‘TEXT’ data type containing non-UTF-8 encodings,
or even arbitrary data.  To demonstrate, let’s assume we have a database
with ISO-8859-2 (Latin-2) encoded text, for example a table of
Czech-English dictionary entries.  Assuming we now have a *note
Connection: 245. instance ‘con’ connected to this database, we can
decode the Latin-2 encoded text using this *note text_factory: 2af5.:

     con.text_factory = lambda data: str(data, encoding="latin2")

For invalid UTF-8 or arbitrary data in stored in ‘TEXT’ table columns,
you can use the following technique, borrowed from the *note Unicode
HOWTO: 12ec.:

     con.text_factory = lambda data: str(data, errors="surrogateescape")

     Note: The ‘sqlite3’ module API does not support strings containing
     surrogates.

See also
........

*note Unicode HOWTO: 12ec.

   ---------- Footnotes ----------

   (1) https://www.sqlite.org/flextypegood.html


File: python.info,  Node: Explanation,  Prev: How-to guides,  Up: sqlite3 — DB-API 2 0 interface for SQLite databases

5.12.6.26 Explanation
.....................

* Menu:

* Transaction control::


File: python.info,  Node: Transaction control,  Up: Explanation

5.12.6.27 Transaction control
.............................

‘sqlite3’ offers multiple methods of controlling whether, when and how
database transactions are opened and closed.  *note Transaction control
via the autocommit attribute: 4ba. is recommended, while *note
Transaction control via the isolation_level attribute: 2ac5. retains the
pre-Python 3.12 behaviour.

* Menu:

* Transaction control via the autocommit attribute::
* Transaction control via the isolation_level attribute::


File: python.info,  Node: Transaction control via the autocommit attribute,  Next: Transaction control via the isolation_level attribute,  Up: Transaction control

5.12.6.28 Transaction control via the ‘autocommit’ attribute
............................................................

The recommended way of controlling transaction behaviour is through the
*note Connection.autocommit: 4b9. attribute, which should preferably be
set using the 'autocommit' parameter of *note connect(): 2a8.

It is suggested to set 'autocommit' to ‘False’, which implies PEP
249(1)-compliant transaction control.  This means:

   * ‘sqlite3’ ensures that a transaction is always open, so *note
     connect(): 2a8, *note Connection.commit(): 2ab7, and *note
     Connection.rollback(): 2ae9. will implicitly open a new transaction
     (immediately after closing the pending one, for the latter two).
     ‘sqlite3’ uses ‘BEGIN DEFERRED’ statements when opening
     transactions.

   * Transactions should be committed explicitly using ‘commit()’.

   * Transactions should be rolled back explicitly using ‘rollback()’.

   * An implicit rollback is performed if the database is *note close():
     246.-ed with pending changes.

Set 'autocommit' to ‘True’ to enable SQLite’s autocommit mode(2).  In
this mode, *note Connection.commit(): 2ab7. and *note
Connection.rollback(): 2ae9. have no effect.  Note that SQLite’s
autocommit mode is distinct from the PEP 249(3)-compliant *note
Connection.autocommit: 4b9. attribute; use *note
Connection.in_transaction: 2af3. to query the low-level SQLite
autocommit mode.

Set 'autocommit' to *note LEGACY_TRANSACTION_CONTROL: 2ac6. to leave
transaction control behaviour to the *note Connection.isolation_level:
2ac4. attribute.  See *note Transaction control via the isolation_level
attribute: 2ac5. for more information.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0249/

   (2) 
https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions

   (3) https://peps.python.org/pep-0249/


File: python.info,  Node: Transaction control via the isolation_level attribute,  Prev: Transaction control via the autocommit attribute,  Up: Transaction control

5.12.6.29 Transaction control via the ‘isolation_level’ attribute
.................................................................

     Note: The recommended way of controlling transactions is via the
     *note autocommit: 4b9. attribute.  See *note Transaction control
     via the autocommit attribute: 4ba.

If *note Connection.autocommit: 4b9. is set to *note
LEGACY_TRANSACTION_CONTROL: 2ac6. (the default), transaction behaviour
is controlled using the *note Connection.isolation_level: 2ac4.
attribute.  Otherwise, ‘isolation_level’ has no effect.

If the connection attribute *note isolation_level: 2ac4. is not ‘None’,
new transactions are implicitly opened before *note execute(): 2d1. and
*note executemany(): 2d2. executes ‘INSERT’, ‘UPDATE’, ‘DELETE’, or
‘REPLACE’ statements; for other statements, no implicit transaction
handling is performed.  Use the *note commit(): 2ab7. and *note
rollback(): 2ae9. methods to respectively commit and roll back pending
transactions.  You can choose the underlying SQLite transaction
behaviour(1) — that is, whether and what type of ‘BEGIN’ statements
‘sqlite3’ implicitly executes – via the ‘isolation_level’ attribute.

If *note isolation_level: 2ac4. is set to ‘None’, no transactions are
implicitly opened at all.  This leaves the underlying SQLite library in
autocommit mode(2), but also allows the user to perform their own
transaction handling using explicit SQL statements.  The underlying
SQLite library autocommit mode can be queried using the *note
in_transaction: 2af3. attribute.

The *note executescript(): 2aed. method implicitly commits any pending
transaction before execution of the given SQL script, regardless of the
value of *note isolation_level: 2ac4.

Changed in version 3.6: ‘sqlite3’ used to implicitly commit an open
transaction before DDL statements.  This is no longer the case.

Changed in version 3.12: The recommended way of controlling transactions
is now via the *note autocommit: 4b9. attribute.

   ---------- Footnotes ----------

   (1) 
https://www.sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions

   (2) 
https://www.sqlite.org/lang_transaction.html#implicit_versus_explicit_transactions


File: python.info,  Node: Data Compression and Archiving,  Next: File Formats,  Prev: Data Persistence,  Up: The Python Standard Library

5.13 Data Compression and Archiving
===================================

The modules described in this chapter support data compression with the
zlib, gzip, bzip2 and lzma algorithms, and the creation of ZIP- and
tar-format archives.  See also *note Archiving operations: 125e.
provided by the *note shutil: c5. module.

* Menu:

* zlib — Compression compatible with gzip::
* gzip — Support for gzip files::
* bz2 — Support for bzip2 compression::
* lzma — Compression using the LZMA algorithm::
* zipfile — Work with ZIP archives::
* tarfile — Read and write tar archive files::


File: python.info,  Node: zlib — Compression compatible with gzip,  Next: gzip — Support for gzip files,  Up: Data Compression and Archiving

5.13.1 ‘zlib’ — Compression compatible with ‘gzip’
--------------------------------------------------

__________________________________________________________________

For applications that require data compression, the functions in this
module allow compression and decompression, using the zlib library.  The
zlib library has its own home page at ‘https://www.zlib.net’.  There are
known incompatibilities between the Python module and versions of the
zlib library earlier than 1.1.3; 1.1.3 has a security vulnerability(1),
so we recommend using 1.1.4 or later.

zlib’s functions have many options and often need to be used in a
particular order.  This documentation doesn’t attempt to cover all of
the permutations; consult the zlib manual(2) for authoritative
information.

For reading and writing ‘.gz’ files see the *note gzip: 67. module.

The available exception and functions in this module are:

 -- Exception: zlib.error

     Exception raised on compression and decompression errors.

 -- Function: zlib.adler32 (data[, value])

     Computes an Adler-32 checksum of 'data'.  (An Adler-32 checksum is
     almost as reliable as a CRC32 but can be computed much more
     quickly.)  The result is an unsigned 32-bit integer.  If 'value' is
     present, it is used as the starting value of the checksum;
     otherwise, a default value of 1 is used.  Passing in 'value' allows
     computing a running checksum over the concatenation of several
     inputs.  The algorithm is not cryptographically strong, and should
     not be used for authentication or digital signatures.  Since the
     algorithm is designed for use as a checksum algorithm, it is not
     suitable for use as a general hash algorithm.

     Changed in version 3.0: The result is always unsigned.

 -- Function: zlib.compress (data, /, level=Z_DEFAULT_COMPRESSION,
          wbits=MAX_WBITS)

     Compresses the bytes in 'data', returning a bytes object containing
     compressed data.  'level' is an integer from ‘0’ to ‘9’ or ‘-1’
     controlling the level of compression; See *note Z_BEST_SPEED: 2b2c.
     (‘1’), *note Z_BEST_COMPRESSION: 2b2d. (‘9’), *note
     Z_NO_COMPRESSION: 2b2e. (‘0’), and the default, *note
     Z_DEFAULT_COMPRESSION: 2b2f. (‘-1’) for more information about
     these values.  The 'wbits' argument controls the size of the
     history buffer (or the “window size”) used when compressing data,
     and whether a header and trailer is included in the output.  It can
     take several ranges of values, defaulting to ‘15’ (*note MAX_WBITS:
     2b31.):

        * +9 to +15: The base-two logarithm of the window size, which
          therefore ranges between 512 and 32768.  Larger values produce
          better compression at the expense of greater memory usage.
          The resulting output will include a zlib-specific header and
          trailer.

        * −9 to −15: Uses the absolute value of 'wbits' as the window
          size logarithm, while producing a raw output stream with no
          header or trailing checksum.

        * +25 to +31 = 16 + (9 to 15): Uses the low 4 bits of the value
          as the window size logarithm, while including a basic ‘gzip’
          header and trailing checksum in the output.

     Raises the *note error: 2b2b. exception if any error occurs.

     Changed in version 3.6: 'level' can now be used as a keyword
     parameter.

     Changed in version 3.11: The 'wbits' parameter is now available to
     set window bits and compression type.

 -- Function: zlib.compressobj (level=Z_DEFAULT_COMPRESSION,
          method=DEFLATED, wbits=MAX_WBITS, memLevel=DEF_MEM_LEVEL,
          strategy=Z_DEFAULT_STRATEGY[, zdict])

     Returns a compression object, to be used for compressing data
     streams that won’t fit into memory at once.

     'level' is the compression level – an integer from ‘0’ to ‘9’ or
     ‘-1’.  See *note Z_BEST_SPEED: 2b2c. (‘1’), *note
     Z_BEST_COMPRESSION: 2b2d. (‘9’), *note Z_NO_COMPRESSION: 2b2e.
     (‘0’), and the default, *note Z_DEFAULT_COMPRESSION: 2b2f. (‘-1’)
     for more information about these values.

     'method' is the compression algorithm.  Currently, the only
     supported value is *note DEFLATED: 2b33.

     The 'wbits' parameter controls the size of the history buffer (or
     the “window size”), and what header and trailer format will be
     used.  It has the same meaning as *note described for compress():
     2b30.

     The 'memLevel' argument controls the amount of memory used for the
     internal compression state.  Valid values range from ‘1’ to ‘9’.
     Higher values use more memory, but are faster and produce smaller
     output.

     'strategy' is used to tune the compression algorithm.  Possible
     values are *note Z_DEFAULT_STRATEGY: 2b34, *note Z_FILTERED: 2b35,
     *note Z_HUFFMAN_ONLY: 2b36, *note Z_RLE: 2b37. and *note Z_FIXED:
     2b38.

     'zdict' is a predefined compression dictionary.  This is a sequence
     of bytes (such as a *note bytes: 1c2. object) containing
     subsequences that are expected to occur frequently in the data that
     is to be compressed.  Those subsequences that are expected to be
     most common should come at the end of the dictionary.

     Changed in version 3.3: Added the 'zdict' parameter and keyword
     argument support.

 -- Function: zlib.crc32 (data[, value])

     Computes a CRC (Cyclic Redundancy Check) checksum of 'data'.  The
     result is an unsigned 32-bit integer.  If 'value' is present, it is
     used as the starting value of the checksum; otherwise, a default
     value of 0 is used.  Passing in 'value' allows computing a running
     checksum over the concatenation of several inputs.  The algorithm
     is not cryptographically strong, and should not be used for
     authentication or digital signatures.  Since the algorithm is
     designed for use as a checksum algorithm, it is not suitable for
     use as a general hash algorithm.

     Changed in version 3.0: The result is always unsigned.

 -- Function: zlib.decompress (data, /, wbits=MAX_WBITS,
          bufsize=DEF_BUF_SIZE)

     Decompresses the bytes in 'data', returning a bytes object
     containing the uncompressed data.  The 'wbits' parameter depends on
     the format of 'data', and is discussed further below.  If 'bufsize'
     is given, it is used as the initial size of the output buffer.
     Raises the *note error: 2b2b. exception if any error occurs.  The
     'wbits' parameter controls the size of the history buffer (or
     “window size”), and what header and trailer format is expected.  It
     is similar to the parameter for *note compressobj(): 2b32, but
     accepts more ranges of values:

        * +8 to +15: The base-two logarithm of the window size.  The
          input must include a zlib header and trailer.

        * 0: Automatically determine the window size from the zlib
          header.  Only supported since zlib 1.2.3.5.

        * −8 to −15: Uses the absolute value of 'wbits' as the window
          size logarithm.  The input must be a raw stream with no header
          or trailer.

        * +24 to +31 = 16 + (8 to 15): Uses the low 4 bits of the value
          as the window size logarithm.  The input must include a gzip
          header and trailer.

        * +40 to +47 = 32 + (8 to 15): Uses the low 4 bits of the value
          as the window size logarithm, and automatically accepts either
          the zlib or gzip format.

     When decompressing a stream, the window size must not be smaller
     than the size originally used to compress the stream; using a
     too-small value may result in an *note error: 2b2b. exception.  The
     default 'wbits' value corresponds to the largest window size and
     requires a zlib header and trailer to be included.

     'bufsize' is the initial size of the buffer used to hold
     decompressed data.  If more space is required, the buffer size will
     be increased as needed, so you don’t have to get this value exactly
     right; tuning it will only save a few calls to ‘malloc()’.

     Changed in version 3.6: 'wbits' and 'bufsize' can be used as
     keyword arguments.

 -- Function: zlib.decompressobj (wbits=MAX_WBITS[, zdict])

     Returns a decompression object, to be used for decompressing data
     streams that won’t fit into memory at once.

     The 'wbits' parameter controls the size of the history buffer (or
     the “window size”), and what header and trailer format is expected.
     It has the same meaning as *note described for decompress(): 2b39.

     The 'zdict' parameter specifies a predefined compression
     dictionary.  If provided, this must be the same dictionary as was
     used by the compressor that produced the data that is to be
     decompressed.

          Note: If 'zdict' is a mutable object (such as a *note
          bytearray: 2ea.), you must not modify its contents between the
          call to ‘decompressobj()’ and the first call to the
          decompressor’s ‘decompress()’ method.

     Changed in version 3.3: Added the 'zdict' parameter.

Compression objects support the following methods:

 -- Method: Compress.compress (data)

     Compress 'data', returning a bytes object containing compressed
     data for at least part of the data in 'data'.  This data should be
     concatenated to the output produced by any preceding calls to the
     ‘compress()’ method.  Some input may be kept in internal buffers
     for later processing.

 -- Method: Compress.flush ([mode])

     All pending input is processed, and a bytes object containing the
     remaining compressed output is returned.  'mode' can be selected
     from the constants *note Z_NO_FLUSH: 2b3d, *note Z_PARTIAL_FLUSH:
     2b3e, *note Z_SYNC_FLUSH: 2b3f, *note Z_FULL_FLUSH: 2b40, *note
     Z_BLOCK: 2b41, or *note Z_FINISH: 2b42, defaulting to ‘Z_FINISH’.
     Except ‘Z_FINISH’, all constants allow compressing further
     bytestrings of data, while ‘Z_FINISH’ finishes the compressed
     stream and prevents compressing any more data.  After calling
     ‘flush()’ with 'mode' set to ‘Z_FINISH’, the *note compress(): 642.
     method cannot be called again; the only realistic action is to
     delete the object.

 -- Method: Compress.copy ()

     Returns a copy of the compression object.  This can be used to
     efficiently compress a set of data that share a common initial
     prefix.

Changed in version 3.8: Added *note copy.copy(): 537. and *note
copy.deepcopy(): b8a. support to compression objects.

Decompression objects support the following methods and attributes:

 -- Attribute: Decompress.unused_data

     A bytes object which contains any bytes past the end of the
     compressed data.  That is, this remains ‘b""’ until the last byte
     that contains compression data is available.  If the whole
     bytestring turned out to contain compressed data, this is ‘b""’, an
     empty bytes object.

 -- Attribute: Decompress.unconsumed_tail

     A bytes object that contains any data that was not consumed by the
     last *note decompress(): d35. call because it exceeded the limit
     for the uncompressed data buffer.  This data has not yet been seen
     by the zlib machinery, so you must feed it (possibly with further
     data concatenated to it) back to a subsequent ‘decompress()’ method
     call in order to get correct output.

 -- Attribute: Decompress.eof

     A boolean indicating whether the end of the compressed data stream
     has been reached.

     This makes it possible to distinguish between a properly formed
     compressed stream, and an incomplete or truncated one.

     Added in version 3.3.

 -- Method: Decompress.decompress (data, max_length=0)

     Decompress 'data', returning a bytes object containing the
     uncompressed data corresponding to at least part of the data in
     'string'.  This data should be concatenated to the output produced
     by any preceding calls to the ‘decompress()’ method.  Some of the
     input data may be preserved in internal buffers for later
     processing.

     If the optional parameter 'max_length' is non-zero then the return
     value will be no longer than 'max_length'.  This may mean that not
     all of the compressed input can be processed; and unconsumed data
     will be stored in the attribute *note unconsumed_tail: 2b45.  This
     bytestring must be passed to a subsequent call to ‘decompress()’ if
     decompression is to continue.  If 'max_length' is zero then the
     whole input is decompressed, and ‘unconsumed_tail’ is empty.

     Changed in version 3.6: 'max_length' can be used as a keyword
     argument.

 -- Method: Decompress.flush ([length])

     All pending input is processed, and a bytes object containing the
     remaining uncompressed output is returned.  After calling
     ‘flush()’, the *note decompress(): d35. method cannot be called
     again; the only realistic action is to delete the object.

     The optional parameter 'length' sets the initial size of the output
     buffer.

 -- Method: Decompress.copy ()

     Returns a copy of the decompression object.  This can be used to
     save the state of the decompressor midway through the data stream
     in order to speed up random seeks into the stream at a future
     point.

Changed in version 3.8: Added *note copy.copy(): 537. and *note
copy.deepcopy(): b8a. support to decompression objects.

The following constants are available to configure compression and
decompression behavior:

 -- Data: zlib.DEFLATED

     The deflate compression method.

 -- Data: zlib.MAX_WBITS

     The maximum window size, expressed as a power of 2.  For example,
     if ‘MAX_WBITS’ is ‘15’ it results in a window size of ‘32 KiB’.

 -- Data: zlib.DEF_MEM_LEVEL

     The default memory level for compression objects.

 -- Data: zlib.DEF_BUF_SIZE

     The default buffer size for decompression operations.

 -- Data: zlib.Z_NO_COMPRESSION

     Compression level ‘0’; no compression.

     Added in version 3.6.

 -- Data: zlib.Z_BEST_SPEED

     Compression level ‘1’; fastest and produces the least compression.

 -- Data: zlib.Z_BEST_COMPRESSION

     Compression level ‘9’; slowest and produces the most compression.

 -- Data: zlib.Z_DEFAULT_COMPRESSION

     Default compression level (‘-1’); a compromise between speed and
     compression.  Currently equivalent to compression level ‘6’.

 -- Data: zlib.Z_DEFAULT_STRATEGY

     Default compression strategy, for normal data.

 -- Data: zlib.Z_FILTERED

     Compression strategy for data produced by a filter (or predictor).

 -- Data: zlib.Z_HUFFMAN_ONLY

     Compression strategy that forces Huffman coding only.

 -- Data: zlib.Z_RLE

     Compression strategy that limits match distances to one (run-length
     encoding).

     This constant is only available if Python was compiled with zlib
     1.2.0.1 or greater.

     Added in version 3.6.

 -- Data: zlib.Z_FIXED

     Compression strategy that prevents the use of dynamic Huffman
     codes.

     This constant is only available if Python was compiled with zlib
     1.2.2.2 or greater.

     Added in version 3.6.

 -- Data: zlib.Z_NO_FLUSH

     Flush mode ‘0’.  No special flushing behavior.

     Added in version 3.6.

 -- Data: zlib.Z_PARTIAL_FLUSH

     Flush mode ‘1’.  Flush as much output as possible.

 -- Data: zlib.Z_SYNC_FLUSH

     Flush mode ‘2’.  All output is flushed and the output is aligned to
     a byte boundary.

 -- Data: zlib.Z_FULL_FLUSH

     Flush mode ‘3’.  All output is flushed and the compression state is
     reset.

 -- Data: zlib.Z_FINISH

     Flush mode ‘4’.  All pending input is processed, no more input is
     expected.

 -- Data: zlib.Z_BLOCK

     Flush mode ‘5’.  A deflate block is completed and emitted.

     This constant is only available if Python was compiled with zlib
     1.2.2.2 or greater.

     Added in version 3.6.

 -- Data: zlib.Z_TREES

     Flush mode ‘6’, for inflate operations.  Instructs inflate to
     return when it gets to the next deflate block boundary.

     This constant is only available if Python was compiled with zlib
     1.2.3.4 or greater.

     Added in version 3.6.

Information about the version of the zlib library in use is available
through the following constants:

 -- Data: zlib.ZLIB_VERSION

     The version string of the zlib library that was used for building
     the module.  This may be different from the zlib library actually
     used at runtime, which is available as *note ZLIB_RUNTIME_VERSION:
     11b2.

 -- Data: zlib.ZLIB_RUNTIME_VERSION

     The version string of the zlib library actually loaded by the
     interpreter.

     Added in version 3.3.

See also
........

Module *note gzip: 67.

     Reading and writing ‘gzip’-format files.

‘https://www.zlib.net’

     The zlib library home page.

‘https://www.zlib.net/manual.html’

     The zlib manual explains the semantics and usage of the library’s
     many functions.

In case gzip (de)compression is a bottleneck, the python-isal(3) package
speeds up (de)compression with a mostly compatible API.

   ---------- Footnotes ----------

   (1) https://zlib.net/zlib_faq.html#faq33

   (2) https://www.zlib.net/manual.html

   (3) https://github.com/pycompression/python-isal


File: python.info,  Node: gzip — Support for gzip files,  Next: bz2 — Support for bzip2 compression,  Prev: zlib — Compression compatible with gzip,  Up: Data Compression and Archiving

5.13.2 ‘gzip’ — Support for ‘gzip’ files
----------------------------------------

'Source code:' Lib/gzip.py(1)

__________________________________________________________________

This module provides a simple interface to compress and decompress files
just like the GNU programs ‘gzip’ and ‘gunzip’ would.

The data compression is provided by the *note zlib: 133. module.

The ‘gzip’ module provides the *note GzipFile: 41d. class, as well as
the *note open(): 2b50, *note compress(): 641. and *note decompress():
1252. convenience functions.  The ‘GzipFile’ class reads and writes
‘gzip’-format files, automatically compressing or decompressing the data
so that it looks like an ordinary *note file object: 1208.

Note that additional file formats which can be decompressed by the
‘gzip’ and ‘gunzip’ programs, such as those produced by ‘compress’ and
‘pack’, are not supported by this module.

The module defines the following items:

 -- Function: gzip.open (filename, mode='rb', compresslevel=9,
          encoding=None, errors=None, newline=None)

     Open a gzip-compressed file in binary or text mode, returning a
     *note file object: 1208.

     The 'filename' argument can be an actual filename (a *note str:
     44f. or *note bytes: 1c2. object), or an existing file object to
     read from or write to.

     The 'mode' argument can be any of ‘'r'’, ‘'rb'’, ‘'a'’, ‘'ab'’,
     ‘'w'’, ‘'wb'’, ‘'x'’ or ‘'xb'’ for binary mode, or ‘'rt'’, ‘'at'’,
     ‘'wt'’, or ‘'xt'’ for text mode.  The default is ‘'rb'’.

     The 'compresslevel' argument is an integer from 0 to 9, as for the
     *note GzipFile: 41d. constructor.

     For binary mode, this function is equivalent to the *note GzipFile:
     41d. constructor: ‘GzipFile(filename, mode, compresslevel)’.  In
     this case, the 'encoding', 'errors' and 'newline' arguments must
     not be provided.

     For text mode, a *note GzipFile: 41d. object is created, and
     wrapped in an *note io.TextIOWrapper: 7bf. instance with the
     specified encoding, error handling behavior, and line ending(s).

     Changed in version 3.3: Added support for 'filename' being a file
     object, support for text mode, and the 'encoding', 'errors' and
     'newline' arguments.

     Changed in version 3.4: Added support for the ‘'x'’, ‘'xb'’ and
     ‘'xt'’ modes.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Exception: gzip.BadGzipFile

     An exception raised for invalid gzip files.  It inherits from *note
     OSError: 41a.  *note EOFError: 1321. and *note zlib.error: 2b2b.
     can also be raised for invalid gzip files.

     Added in version 3.8.

 -- Class: gzip.GzipFile (filename=None, mode=None, compresslevel=9,
          fileobj=None, mtime=None)

     Constructor for the ‘GzipFile’ class, which simulates most of the
     methods of a *note file object: 1208, with the exception of the
     *note truncate(): 135a. method.  At least one of 'fileobj' and
     'filename' must be given a non-trivial value.

     The new class instance is based on 'fileobj', which can be a
     regular file, an *note io.BytesIO: ed8. object, or any other object
     which simulates a file.  It defaults to ‘None’, in which case
     'filename' is opened to provide a file object.

     When 'fileobj' is not ‘None’, the 'filename' argument is only used
     to be included in the ‘gzip’ file header, which may include the
     original filename of the uncompressed file.  It defaults to the
     filename of 'fileobj', if discernible; otherwise, it defaults to
     the empty string, and in this case the original filename is not
     included in the header.

     The 'mode' argument can be any of ‘'r'’, ‘'rb'’, ‘'a'’, ‘'ab'’,
     ‘'w'’, ‘'wb'’, ‘'x'’, or ‘'xb'’, depending on whether the file will
     be read or written.  The default is the mode of 'fileobj' if
     discernible; otherwise, the default is ‘'rb'’.  In future Python
     releases the mode of 'fileobj' will not be used.  It is better to
     always specify 'mode' for writing.

     Note that the file is always opened in binary mode.  To open a
     compressed file in text mode, use *note open(): 2b50. (or wrap your
     ‘GzipFile’ with an *note io.TextIOWrapper: 7bf.).

     The 'compresslevel' argument is an integer from ‘0’ to ‘9’
     controlling the level of compression; ‘1’ is fastest and produces
     the least compression, and ‘9’ is slowest and produces the most
     compression.  ‘0’ is no compression.  The default is ‘9’.

     The optional 'mtime' argument is the timestamp requested by gzip.
     The time is in Unix format, i.e., seconds since 00:00:00 UTC,
     January 1, 1970.  If 'mtime' is omitted or ‘None’, the current time
     is used.  Use 'mtime' = 0 to generate a compressed stream that does
     not depend on creation time.

     See below for the *note mtime: 2b51. attribute that is set when
     decompressing.

     Calling a ‘GzipFile’ object’s ‘close()’ method does not close
     'fileobj', since you might wish to append more material after the
     compressed data.  This also allows you to pass an *note io.BytesIO:
     ed8. object opened for writing as 'fileobj', and retrieve the
     resulting memory buffer using the ‘io.BytesIO’ object’s *note
     getvalue(): 2b52. method.

     ‘GzipFile’ supports the *note io.BufferedIOBase: 697. interface,
     including iteration and the *note with: 5d5. statement.  Only the
     *note truncate(): 135a. method isn’t implemented.

     ‘GzipFile’ also provides the following method and attribute:

      -- Method: peek (n)

          Read 'n' uncompressed bytes without advancing the file
          position.  The number of bytes returned may be more or less
          than requested.

               Note: While calling ‘peek()’ does not change the file
               position of the ‘GzipFile’, it may change the position of
               the underlying file object (e.g.  if the ‘GzipFile’ was
               constructed with the 'fileobj' parameter).

          Added in version 3.2.

      -- Attribute: mode

          ‘'rb'’ for reading and ‘'wb'’ for writing.

          Changed in version 3.13: In previous versions it was an
          integer ‘1’ or ‘2’.

      -- Attribute: mtime

          When decompressing, this attribute is set to the last
          timestamp in the most recently read header.  It is an integer,
          holding the number of seconds since the Unix epoch (00:00:00
          UTC, January 1, 1970).  The initial value before reading any
          headers is ‘None’.

      -- Attribute: name

          The path to the gzip file on disk, as a *note str: 44f. or
          *note bytes: 1c2.  Equivalent to the output of *note
          os.fspath(): c74. on the original input path, with no other
          normalization, resolution or expansion.

     Changed in version 3.1: Support for the *note with: 5d5. statement
     was added, along with the 'mtime' constructor argument and *note
     mtime: 2b51. attribute.

     Changed in version 3.2: Support for zero-padded and unseekable
     files was added.

     Changed in version 3.3: The *note io.BufferedIOBase.read1(): 2b54.
     method is now implemented.

     Changed in version 3.4: Added support for the ‘'x'’ and ‘'xb'’
     modes.

     Changed in version 3.5: Added support for writing arbitrary *note
     bytes-like objects: d55.  The *note read(): 1372. method now
     accepts an argument of ‘None’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Deprecated since version 3.9: Opening ‘GzipFile’ for writing
     without specifying the 'mode' argument is deprecated.

     Changed in version 3.12: Remove the ‘filename’ attribute, use the
     *note name: 510. attribute instead.

 -- Function: gzip.compress (data, compresslevel=9, *, mtime=None)

     Compress the 'data', returning a *note bytes: 1c2. object
     containing the compressed data.  'compresslevel' and 'mtime' have
     the same meaning as in the *note GzipFile: 41d. constructor above.

     Added in version 3.2.

     Changed in version 3.8: Added the 'mtime' parameter for
     reproducible output.

     Changed in version 3.11: Speed is improved by compressing all data
     at once instead of in a streamed fashion.  Calls with 'mtime' set
     to ‘0’ are delegated to *note zlib.compress(): 642. for better
     speed.  In this situation the output may contain a gzip header “OS”
     byte value other than 255 “unknown” as supplied by the underlying
     zlib implementation.

     Changed in version 3.13: The gzip header OS byte is guaranteed to
     be set to 255 when this function is used as was the case in 3.10
     and earlier.

 -- Function: gzip.decompress (data)

     Decompress the 'data', returning a *note bytes: 1c2. object
     containing the uncompressed data.  This function is capable of
     decompressing multi-member gzip data (multiple gzip blocks
     concatenated together).  When the data is certain to contain only
     one member the *note zlib.decompress(): d35. function with 'wbits'
     set to 31 is faster.

     Added in version 3.2.

     Changed in version 3.11: Speed is improved by decompressing members
     at once in memory instead of in a streamed fashion.

* Menu:

* Examples of usage::
* Command-line interface: Command-line interface<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/gzip.py


File: python.info,  Node: Examples of usage,  Next: Command-line interface<2>,  Up: gzip — Support for gzip files

5.13.2.1 Examples of usage
..........................

Example of how to read a compressed file:

     import gzip
     with gzip.open('/home/joe/file.txt.gz', 'rb') as f:
         file_content = f.read()

Example of how to create a compressed GZIP file:

     import gzip
     content = b"Lots of content here"
     with gzip.open('/home/joe/file.txt.gz', 'wb') as f:
         f.write(content)

Example of how to GZIP compress an existing file:

     import gzip
     import shutil
     with open('/home/joe/file.txt', 'rb') as f_in:
         with gzip.open('/home/joe/file.txt.gz', 'wb') as f_out:
             shutil.copyfileobj(f_in, f_out)

Example of how to GZIP compress a binary string:

     import gzip
     s_in = b"Lots of content here"
     s_out = gzip.compress(s_in)

See also
........

Module *note zlib: 133.

     The basic data compression module needed to support the ‘gzip’ file
     format.

In case gzip (de)compression is a bottleneck, the python-isal(1) package
speeds up (de)compression with a mostly compatible API.

   ---------- Footnotes ----------

   (1) https://github.com/pycompression/python-isal


File: python.info,  Node: Command-line interface<2>,  Prev: Examples of usage,  Up: gzip — Support for gzip files

5.13.2.2 Command-line interface
...............................

The ‘gzip’ module provides a simple command line interface to compress
or decompress files.

Once executed the ‘gzip’ module keeps the input file(s).

Changed in version 3.8: Add a new command line interface with a usage.
By default, when you will execute the CLI, the default compression level
is 6.

* Menu:

* Command-line options::


File: python.info,  Node: Command-line options,  Up: Command-line interface<2>

5.13.2.3 Command-line options
.............................

 -- Option: file

     If 'file' is not specified, read from *note sys.stdin: 540.

 -- Option: --fast

     Indicates the fastest compression method (less compression).

 -- Option: --best

     Indicates the slowest compression method (best compression).

 -- Option: -d, --decompress

     Decompress the given file.

 -- Option: -h, --help

     Show the help message.


File: python.info,  Node: bz2 — Support for bzip2 compression,  Next: lzma — Compression using the LZMA algorithm,  Prev: gzip — Support for gzip files,  Up: Data Compression and Archiving

5.13.3 ‘bz2’ — Support for ‘bzip2’ compression
----------------------------------------------

'Source code:' Lib/bz2.py(1)

__________________________________________________________________

This module provides a comprehensive interface for compressing and
decompressing data using the bzip2 compression algorithm.

The ‘bz2’ module contains:

   * The *note open(): 10d1. function and *note BZ2File: 86d. class for
     reading and writing compressed files.

   * The *note BZ2Compressor: 1871. and *note BZ2Decompressor: 186f.
     classes for incremental (de)compression.

   * The *note compress(): 25cc. and *note decompress(): 10d2. functions
     for one-shot (de)compression.

* Menu:

* (De)compression of files: De compression of files.
* Incremental (de)compression: Incremental de compression.
* One-shot (de)compression: One-shot de compression.
* Examples of usage: Examples of usage<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/bz2.py


File: python.info,  Node: De compression of files,  Next: Incremental de compression,  Up: bz2 — Support for bzip2 compression

5.13.3.1 (De)compression of files
.................................

 -- Function: bz2.open (filename, mode='rb', compresslevel=9,
          encoding=None, errors=None, newline=None)

     Open a bzip2-compressed file in binary or text mode, returning a
     *note file object: 1208.

     As with the constructor for *note BZ2File: 86d, the 'filename'
     argument can be an actual filename (a *note str: 44f. or *note
     bytes: 1c2. object), or an existing file object to read from or
     write to.

     The 'mode' argument can be any of ‘'r'’, ‘'rb'’, ‘'w'’, ‘'wb'’,
     ‘'x'’, ‘'xb'’, ‘'a'’ or ‘'ab'’ for binary mode, or ‘'rt'’, ‘'wt'’,
     ‘'xt'’, or ‘'at'’ for text mode.  The default is ‘'rb'’.

     The 'compresslevel' argument is an integer from 1 to 9, as for the
     *note BZ2File: 86d. constructor.

     For binary mode, this function is equivalent to the *note BZ2File:
     86d. constructor: ‘BZ2File(filename, mode,
     compresslevel=compresslevel)’.  In this case, the 'encoding',
     'errors' and 'newline' arguments must not be provided.

     For text mode, a *note BZ2File: 86d. object is created, and wrapped
     in an *note io.TextIOWrapper: 7bf. instance with the specified
     encoding, error handling behavior, and line ending(s).

     Added in version 3.3.

     Changed in version 3.4: The ‘'x'’ (exclusive creation) mode was
     added.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Class: bz2.BZ2File (filename, mode='r', *, compresslevel=9)

     Open a bzip2-compressed file in binary mode.

     If 'filename' is a *note str: 44f. or *note bytes: 1c2. object,
     open the named file directly.  Otherwise, 'filename' should be a
     *note file object: 1208, which will be used to read or write the
     compressed data.

     The 'mode' argument can be either ‘'r'’ for reading (default),
     ‘'w'’ for overwriting, ‘'x'’ for exclusive creation, or ‘'a'’ for
     appending.  These can equivalently be given as ‘'rb'’, ‘'wb'’,
     ‘'xb'’ and ‘'ab'’ respectively.

     If 'filename' is a file object (rather than an actual file name), a
     mode of ‘'w'’ does not truncate the file, and is instead equivalent
     to ‘'a'’.

     If 'mode' is ‘'w'’ or ‘'a'’, 'compresslevel' can be an integer
     between ‘1’ and ‘9’ specifying the level of compression: ‘1’
     produces the least compression, and ‘9’ (default) produces the most
     compression.

     If 'mode' is ‘'r'’, the input file may be the concatenation of
     multiple compressed streams.

     ‘BZ2File’ provides all of the members specified by the *note
     io.BufferedIOBase: 697, except for *note detach(): 2b65. and *note
     truncate(): 135a.  Iteration and the *note with: 5d5. statement are
     supported.

     ‘BZ2File’ also provides the following methods and attributes:

      -- Method: peek ([n])

          Return buffered data without advancing the file position.  At
          least one byte of data will be returned (unless at EOF). The
          exact number of bytes returned is unspecified.

               Note: While calling ‘peek()’ does not change the file
               position of the ‘BZ2File’, it may change the position of
               the underlying file object (e.g.  if the ‘BZ2File’ was
               constructed by passing a file object for 'filename').

          Added in version 3.3.

      -- Method: fileno ()

          Return the file descriptor for the underlying file.

          Added in version 3.3.

      -- Method: readable ()

          Return whether the file was opened for reading.

          Added in version 3.3.

      -- Method: seekable ()

          Return whether the file supports seeking.

          Added in version 3.3.

      -- Method: writable ()

          Return whether the file was opened for writing.

          Added in version 3.3.

      -- Method: read1 (size=-1)

          Read up to 'size' uncompressed bytes, while trying to avoid
          making multiple reads from the underlying stream.  Reads up to
          a buffer’s worth of data if size is negative.

          Returns ‘b''’ if the file is at EOF.

          Added in version 3.3.

      -- Method: readinto (b)

          Read bytes into 'b'.

          Returns the number of bytes read (0 for EOF).

          Added in version 3.3.

      -- Attribute: mode

          ‘'rb'’ for reading and ‘'wb'’ for writing.

          Added in version 3.13.

      -- Attribute: name

          The bzip2 file name.  Equivalent to the *note name: 2b6f.
          attribute of the underlying *note file object: 1208.

          Added in version 3.13.

     Changed in version 3.1: Support for the *note with: 5d5. statement
     was added.

     Changed in version 3.3: Support was added for 'filename' being a
     *note file object: 1208. instead of an actual filename.

     The ‘'a'’ (append) mode was added, along with support for reading
     multi-stream files.

     Changed in version 3.4: The ‘'x'’ (exclusive creation) mode was
     added.

     Changed in version 3.5: The *note read(): 1372. method now accepts
     an argument of ‘None’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.9: The 'buffering' parameter has been removed.
     It was ignored and deprecated since Python 3.0.  Pass an open file
     object to control how the file is opened.

     The 'compresslevel' parameter became keyword-only.

     Changed in version 3.10: This class is thread unsafe in the face of
     multiple simultaneous readers or writers, just like its equivalent
     classes in *note gzip: 67. and *note lzma: 8a. have always been.


File: python.info,  Node: Incremental de compression,  Next: One-shot de compression,  Prev: De compression of files,  Up: bz2 — Support for bzip2 compression

5.13.3.2 Incremental (de)compression
....................................

 -- Class: bz2.BZ2Compressor (compresslevel=9)

     Create a new compressor object.  This object may be used to
     compress data incrementally.  For one-shot compression, use the
     *note compress(): 25cc. function instead.

     'compresslevel', if given, must be an integer between ‘1’ and ‘9’.
     The default is ‘9’.

      -- Method: compress (data)

          Provide data to the compressor object.  Returns a chunk of
          compressed data if possible, or an empty byte string
          otherwise.

          When you have finished providing data to the compressor, call
          the *note flush(): 2b72. method to finish the compression
          process.

      -- Method: flush ()

          Finish the compression process.  Returns the compressed data
          left in internal buffers.

          The compressor object may not be used after this method has
          been called.

 -- Class: bz2.BZ2Decompressor

     Create a new decompressor object.  This object may be used to
     decompress data incrementally.  For one-shot compression, use the
     *note decompress(): 10d2. function instead.

          Note: This class does not transparently handle inputs
          containing multiple compressed streams, unlike *note
          decompress(): 10d2. and *note BZ2File: 86d.  If you need to
          decompress a multi-stream input with ‘BZ2Decompressor’, you
          must use a new decompressor for each stream.

      -- Method: decompress (data, max_length=-1)

          Decompress 'data' (a *note bytes-like object: d55.), returning
          uncompressed data as bytes.  Some of 'data' may be buffered
          internally, for use in later calls to ‘decompress()’.  The
          returned data should be concatenated with the output of any
          previous calls to ‘decompress()’.

          If 'max_length' is nonnegative, returns at most 'max_length'
          bytes of decompressed data.  If this limit is reached and
          further output can be produced, the *note needs_input: 2b73.
          attribute will be set to ‘False’.  In this case, the next call
          to ‘decompress()’ may provide 'data' as ‘b''’ to obtain more
          of the output.

          If all of the input data was decompressed and returned (either
          because this was less than 'max_length' bytes, or because
          'max_length' was negative), the *note needs_input: 2b73.
          attribute will be set to ‘True’.

          Attempting to decompress data after the end of stream is
          reached raises an *note EOFError: 1321.  Any data found after
          the end of the stream is ignored and saved in the *note
          unused_data: 2b74. attribute.

          Changed in version 3.5: Added the 'max_length' parameter.

      -- Attribute: eof

          ‘True’ if the end-of-stream marker has been reached.

          Added in version 3.3.

      -- Attribute: unused_data

          Data found after the end of the compressed stream.

          If this attribute is accessed before the end of the stream has
          been reached, its value will be ‘b''’.

      -- Attribute: needs_input

          ‘False’ if the *note decompress(): dfa. method can provide
          more decompressed data before requiring new uncompressed
          input.

          Added in version 3.5.


File: python.info,  Node: One-shot de compression,  Next: Examples of usage<2>,  Prev: Incremental de compression,  Up: bz2 — Support for bzip2 compression

5.13.3.3 One-shot (de)compression
.................................

 -- Function: bz2.compress (data, compresslevel=9)

     Compress 'data', a *note bytes-like object: d55.

     'compresslevel', if given, must be an integer between ‘1’ and ‘9’.
     The default is ‘9’.

     For incremental compression, use a *note BZ2Compressor: 1871.
     instead.

 -- Function: bz2.decompress (data)

     Decompress 'data', a *note bytes-like object: d55.

     If 'data' is the concatenation of multiple compressed streams,
     decompress all of the streams.

     For incremental decompression, use a *note BZ2Decompressor: 186f.
     instead.

     Changed in version 3.3: Support for multi-stream inputs was added.


File: python.info,  Node: Examples of usage<2>,  Prev: One-shot de compression,  Up: bz2 — Support for bzip2 compression

5.13.3.4 Examples of usage
..........................

Below are some examples of typical usage of the ‘bz2’ module.

Using *note compress(): 25cc. and *note decompress(): 10d2. to
demonstrate round-trip compression:

     >>> import bz2
     >>> data = b"""\
     ... Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue
     ... nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,
     ... sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus
     ... pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.
     ... Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo
     ... felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum
     ... dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""
     >>> c = bz2.compress(data)
     >>> len(data) / len(c)  # Data compression ratio
     1.513595166163142
     >>> d = bz2.decompress(c)
     >>> data == d  # Check equality to original object after round-trip
     True

Using *note BZ2Compressor: 1871. for incremental compression:

     >>> import bz2
     >>> def gen_data(chunks=10, chunksize=1000):
     ...     """Yield incremental blocks of chunksize bytes."""
     ...     for _ in range(chunks):
     ...         yield b"z" * chunksize
     ...
     >>> comp = bz2.BZ2Compressor()
     >>> out = b""
     >>> for chunk in gen_data():
     ...     # Provide data to the compressor object
     ...     out = out + comp.compress(chunk)
     ...
     >>> # Finish the compression process.  Call this once you have
     >>> # finished providing data to the compressor.
     >>> out = out + comp.flush()

The example above uses a very “nonrandom” stream of data (a stream of
‘b"z"’ chunks).  Random data tends to compress poorly, while ordered,
repetitive data usually yields a high compression ratio.

Writing and reading a bzip2-compressed file in binary mode:

     >>> import bz2
     >>> data = b"""\
     ... Donec rhoncus quis sapien sit amet molestie. Fusce scelerisque vel augue
     ... nec ullamcorper. Nam rutrum pretium placerat. Aliquam vel tristique lorem,
     ... sit amet cursus ante. In interdum laoreet mi, sit amet ultrices purus
     ... pulvinar a. Nam gravida euismod magna, non varius justo tincidunt feugiat.
     ... Aliquam pharetra lacus non risus vehicula rutrum. Maecenas aliquam leo
     ... felis. Pellentesque semper nunc sit amet nibh ullamcorper, ac elementum
     ... dolor luctus. Curabitur lacinia mi ornare consectetur vestibulum."""
     >>> with bz2.open("myfile.bz2", "wb") as f:
     ...     # Write compressed data to file
     ...     unused = f.write(data)
     ...
     >>> with bz2.open("myfile.bz2", "rb") as f:
     ...     # Decompress data from file
     ...     content = f.read()
     ...
     >>> content == data  # Check equality to original object after round-trip
     True


File: python.info,  Node: lzma — Compression using the LZMA algorithm,  Next: zipfile — Work with ZIP archives,  Prev: bz2 — Support for bzip2 compression,  Up: Data Compression and Archiving

5.13.4 ‘lzma’ — Compression using the LZMA algorithm
----------------------------------------------------

Added in version 3.3.

'Source code:' Lib/lzma.py(1)

__________________________________________________________________

This module provides classes and convenience functions for compressing
and decompressing data using the LZMA compression algorithm.  Also
included is a file interface supporting the ‘.xz’ and legacy ‘.lzma’
file formats used by the ‘xz’ utility, as well as raw compressed
streams.

The interface provided by this module is very similar to that of the
*note bz2: 13. module.  Note that *note LZMAFile: 1047. and *note
bz2.BZ2File: 86d. are 'not' thread-safe, so if you need to use a single
‘LZMAFile’ instance from multiple threads, it is necessary to protect it
with a lock.

 -- Exception: lzma.LZMAError

     This exception is raised when an error occurs during compression or
     decompression, or while initializing the compressor/decompressor
     state.

* Menu:

* Reading and writing compressed files::
* Compressing and decompressing data in memory::
* Miscellaneous: Miscellaneous<2>.
* Specifying custom filter chains::
* Examples: Examples<8>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/lzma.py


File: python.info,  Node: Reading and writing compressed files,  Next: Compressing and decompressing data in memory,  Up: lzma — Compression using the LZMA algorithm

5.13.4.1 Reading and writing compressed files
.............................................

 -- Function: lzma.open (filename, mode='rb', *, format=None, check=-1,
          preset=None, filters=None, encoding=None, errors=None,
          newline=None)

     Open an LZMA-compressed file in binary or text mode, returning a
     *note file object: 1208.

     The 'filename' argument can be either an actual file name (given as
     a *note str: 44f, *note bytes: 1c2. or *note path-like: 2a0.
     object), in which case the named file is opened, or it can be an
     existing file object to read from or write to.

     The 'mode' argument can be any of ‘"r"’, ‘"rb"’, ‘"w"’, ‘"wb"’,
     ‘"x"’, ‘"xb"’, ‘"a"’ or ‘"ab"’ for binary mode, or ‘"rt"’, ‘"wt"’,
     ‘"xt"’, or ‘"at"’ for text mode.  The default is ‘"rb"’.

     When opening a file for reading, the 'format' and 'filters'
     arguments have the same meanings as for *note LZMADecompressor:
     186e.  In this case, the 'check' and 'preset' arguments should not
     be used.

     When opening a file for writing, the 'format', 'check', 'preset'
     and 'filters' arguments have the same meanings as for *note
     LZMACompressor: 1870.

     For binary mode, this function is equivalent to the *note LZMAFile:
     1047. constructor: ‘LZMAFile(filename, mode, ...)’.  In this case,
     the 'encoding', 'errors' and 'newline' arguments must not be
     provided.

     For text mode, a *note LZMAFile: 1047. object is created, and
     wrapped in an *note io.TextIOWrapper: 7bf. instance with the
     specified encoding, error handling behavior, and line ending(s).

     Changed in version 3.4: Added support for the ‘"x"’, ‘"xb"’ and
     ‘"xt"’ modes.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Class: lzma.LZMAFile (filename=None, mode='r', *, format=None,
          check=-1, preset=None, filters=None)

     Open an LZMA-compressed file in binary mode.

     An ‘LZMAFile’ can wrap an already-open *note file object: 1208, or
     operate directly on a named file.  The 'filename' argument
     specifies either the file object to wrap, or the name of the file
     to open (as a *note str: 44f, *note bytes: 1c2. or *note path-like:
     2a0. object).  When wrapping an existing file object, the wrapped
     file will not be closed when the ‘LZMAFile’ is closed.

     The 'mode' argument can be either ‘"r"’ for reading (default),
     ‘"w"’ for overwriting, ‘"x"’ for exclusive creation, or ‘"a"’ for
     appending.  These can equivalently be given as ‘"rb"’, ‘"wb"’,
     ‘"xb"’ and ‘"ab"’ respectively.

     If 'filename' is a file object (rather than an actual file name), a
     mode of ‘"w"’ does not truncate the file, and is instead equivalent
     to ‘"a"’.

     When opening a file for reading, the input file may be the
     concatenation of multiple separate compressed streams.  These are
     transparently decoded as a single logical stream.

     When opening a file for reading, the 'format' and 'filters'
     arguments have the same meanings as for *note LZMADecompressor:
     186e.  In this case, the 'check' and 'preset' arguments should not
     be used.

     When opening a file for writing, the 'format', 'check', 'preset'
     and 'filters' arguments have the same meanings as for *note
     LZMACompressor: 1870.

     ‘LZMAFile’ supports all the members specified by *note
     io.BufferedIOBase: 697, except for *note detach(): 2b65. and *note
     truncate(): 135a.  Iteration and the *note with: 5d5. statement are
     supported.

     The following method and attributes are also provided:

      -- Method: peek (size=-1)

          Return buffered data without advancing the file position.  At
          least one byte of data will be returned, unless EOF has been
          reached.  The exact number of bytes returned is unspecified
          (the 'size' argument is ignored).

               Note: While calling ‘peek()’ does not change the file
               position of the ‘LZMAFile’, it may change the position of
               the underlying file object (e.g.  if the ‘LZMAFile’ was
               constructed by passing a file object for 'filename').

      -- Attribute: mode

          ‘'rb'’ for reading and ‘'wb'’ for writing.

          Added in version 3.13.

      -- Attribute: name

          The lzma file name.  Equivalent to the *note name: 2b6f.
          attribute of the underlying *note file object: 1208.

          Added in version 3.13.

     Changed in version 3.4: Added support for the ‘"x"’ and ‘"xb"’
     modes.

     Changed in version 3.5: The *note read(): 1372. method now accepts
     an argument of ‘None’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.


File: python.info,  Node: Compressing and decompressing data in memory,  Next: Miscellaneous<2>,  Prev: Reading and writing compressed files,  Up: lzma — Compression using the LZMA algorithm

5.13.4.2 Compressing and decompressing data in memory
.....................................................

 -- Class: lzma.LZMACompressor (format=FORMAT_XZ, check=-1, preset=None,
          filters=None)

     Create a compressor object, which can be used to compress data
     incrementally.

     For a more convenient way of compressing a single chunk of data,
     see *note compress(): 2b83.

     The 'format' argument specifies what container format should be
     used.  Possible values are:

        * 
          ‘FORMAT_XZ’: The ‘.xz’ container format.

               This is the default format.

        * 
          ‘FORMAT_ALONE’: The legacy ‘.lzma’ container format.

               This format is more limited than ‘.xz’ – it does not
               support integrity checks or multiple filters.

        * 
          ‘FORMAT_RAW’: A raw data stream, not using any container format.

               This format specifier does not support integrity checks,
               and requires that you always specify a custom filter
               chain (for both compression and decompression).
               Additionally, data compressed in this manner cannot be
               decompressed using ‘FORMAT_AUTO’ (see *note
               LZMADecompressor: 186e.).

     The 'check' argument specifies the type of integrity check to
     include in the compressed data.  This check is used when
     decompressing, to ensure that the data has not been corrupted.
     Possible values are:

        * ‘CHECK_NONE’: No integrity check.  This is the default (and
          the only acceptable value) for ‘FORMAT_ALONE’ and
          ‘FORMAT_RAW’.

        * ‘CHECK_CRC32’: 32-bit Cyclic Redundancy Check.

        * ‘CHECK_CRC64’: 64-bit Cyclic Redundancy Check.  This is the
          default for ‘FORMAT_XZ’.

        * ‘CHECK_SHA256’: 256-bit Secure Hash Algorithm.

     If the specified check is not supported, an *note LZMAError: 2b7c.
     is raised.

     The compression settings can be specified either as a preset
     compression level (with the 'preset' argument), or in detail as a
     custom filter chain (with the 'filters' argument).

     The 'preset' argument (if provided) should be an integer between
     ‘0’ and ‘9’ (inclusive), optionally OR-ed with the constant
     ‘PRESET_EXTREME’.  If neither 'preset' nor 'filters' are given, the
     default behavior is to use ‘PRESET_DEFAULT’ (preset level ‘6’).
     Higher presets produce smaller output, but make the compression
     process slower.

          Note: In addition to being more CPU-intensive, compression
          with higher presets also requires much more memory (and
          produces output that needs more memory to decompress).  With
          preset ‘9’ for example, the overhead for an ‘LZMACompressor’
          object can be as high as 800 MiB. For this reason, it is
          generally best to stick with the default preset.

     The 'filters' argument (if provided) should be a filter chain
     specifier.  See *note Specifying custom filter chains: 2b84. for
     details.

      -- Method: compress (data)

          Compress 'data' (a *note bytes: 1c2. object), returning a
          ‘bytes’ object containing compressed data for at least part of
          the input.  Some of 'data' may be buffered internally, for use
          in later calls to ‘compress()’ and *note flush(): 2b86.  The
          returned data should be concatenated with the output of any
          previous calls to ‘compress()’.

      -- Method: flush ()

          Finish the compression process, returning a *note bytes: 1c2.
          object containing any data stored in the compressor’s internal
          buffers.

          The compressor cannot be used after this method has been
          called.

 -- Class: lzma.LZMADecompressor (format=FORMAT_AUTO, memlimit=None,
          filters=None)

     Create a decompressor object, which can be used to decompress data
     incrementally.

     For a more convenient way of decompressing an entire compressed
     stream at once, see *note decompress(): 2b87.

     The 'format' argument specifies the container format that should be
     used.  The default is ‘FORMAT_AUTO’, which can decompress both
     ‘.xz’ and ‘.lzma’ files.  Other possible values are ‘FORMAT_XZ’,
     ‘FORMAT_ALONE’, and ‘FORMAT_RAW’.

     The 'memlimit' argument specifies a limit (in bytes) on the amount
     of memory that the decompressor can use.  When this argument is
     used, decompression will fail with an *note LZMAError: 2b7c. if it
     is not possible to decompress the input within the given memory
     limit.

     The 'filters' argument specifies the filter chain that was used to
     create the stream being decompressed.  This argument is required if
     'format' is ‘FORMAT_RAW’, but should not be used for other formats.
     See *note Specifying custom filter chains: 2b84. for more
     information about filter chains.

          Note: This class does not transparently handle inputs
          containing multiple compressed streams, unlike *note
          decompress(): 2b87. and *note LZMAFile: 1047.  To decompress a
          multi-stream input with ‘LZMADecompressor’, you must create a
          new decompressor for each stream.

      -- Method: decompress (data, max_length=-1)

          Decompress 'data' (a *note bytes-like object: d55.), returning
          uncompressed data as bytes.  Some of 'data' may be buffered
          internally, for use in later calls to ‘decompress()’.  The
          returned data should be concatenated with the output of any
          previous calls to ‘decompress()’.

          If 'max_length' is nonnegative, returns at most 'max_length'
          bytes of decompressed data.  If this limit is reached and
          further output can be produced, the *note needs_input: 2b88.
          attribute will be set to ‘False’.  In this case, the next call
          to ‘decompress()’ may provide 'data' as ‘b''’ to obtain more
          of the output.

          If all of the input data was decompressed and returned (either
          because this was less than 'max_length' bytes, or because
          'max_length' was negative), the *note needs_input: 2b88.
          attribute will be set to ‘True’.

          Attempting to decompress data after the end of stream is
          reached raises an *note EOFError: 1321.  Any data found after
          the end of the stream is ignored and saved in the *note
          unused_data: 2b89. attribute.

          Changed in version 3.5: Added the 'max_length' parameter.

      -- Attribute: check

          The ID of the integrity check used by the input stream.  This
          may be ‘CHECK_UNKNOWN’ until enough of the input has been
          decoded to determine what integrity check it uses.

      -- Attribute: eof

          ‘True’ if the end-of-stream marker has been reached.

      -- Attribute: unused_data

          Data found after the end of the compressed stream.

          Before the end of the stream is reached, this will be ‘b""’.

      -- Attribute: needs_input

          ‘False’ if the *note decompress(): e61. method can provide
          more decompressed data before requiring new uncompressed
          input.

          Added in version 3.5.

 -- Function: lzma.compress (data, format=FORMAT_XZ, check=-1,
          preset=None, filters=None)

     Compress 'data' (a *note bytes: 1c2. object), returning the
     compressed data as a ‘bytes’ object.

     See *note LZMACompressor: 1870. above for a description of the
     'format', 'check', 'preset' and 'filters' arguments.

 -- Function: lzma.decompress (data, format=FORMAT_AUTO, memlimit=None,
          filters=None)

     Decompress 'data' (a *note bytes: 1c2. object), returning the
     uncompressed data as a ‘bytes’ object.

     If 'data' is the concatenation of multiple distinct compressed
     streams, decompress all of these streams, and return the
     concatenation of the results.

     See *note LZMADecompressor: 186e. above for a description of the
     'format', 'memlimit' and 'filters' arguments.


File: python.info,  Node: Miscellaneous<2>,  Next: Specifying custom filter chains,  Prev: Compressing and decompressing data in memory,  Up: lzma — Compression using the LZMA algorithm

5.13.4.3 Miscellaneous
......................

 -- Function: lzma.is_check_supported (check)

     Return ‘True’ if the given integrity check is supported on this
     system.

     ‘CHECK_NONE’ and ‘CHECK_CRC32’ are always supported.  ‘CHECK_CRC64’
     and ‘CHECK_SHA256’ may be unavailable if you are using a version of
     ‘liblzma’ that was compiled with a limited feature set.


File: python.info,  Node: Specifying custom filter chains,  Next: Examples<8>,  Prev: Miscellaneous<2>,  Up: lzma — Compression using the LZMA algorithm

5.13.4.4 Specifying custom filter chains
........................................

A filter chain specifier is a sequence of dictionaries, where each
dictionary contains the ID and options for a single filter.  Each
dictionary must contain the key ‘"id"’, and may contain additional keys
to specify filter-dependent options.  Valid filter IDs are as follows:

   * Compression filters:

        * ‘FILTER_LZMA1’ (for use with ‘FORMAT_ALONE’)

        * ‘FILTER_LZMA2’ (for use with ‘FORMAT_XZ’ and ‘FORMAT_RAW’)

   * Delta filter:

        * ‘FILTER_DELTA’

   * Branch-Call-Jump (BCJ) filters:

        * ‘FILTER_X86’

        * ‘FILTER_IA64’

        * ‘FILTER_ARM’

        * ‘FILTER_ARMTHUMB’

        * ‘FILTER_POWERPC’

        * ‘FILTER_SPARC’

A filter chain can consist of up to 4 filters, and cannot be empty.  The
last filter in the chain must be a compression filter, and any other
filters must be delta or BCJ filters.

Compression filters support the following options (specified as
additional entries in the dictionary representing the filter):

   * ‘preset’: A compression preset to use as a source of default values
     for options that are not specified explicitly.

   * ‘dict_size’: Dictionary size in bytes.  This should be between 4
     KiB and 1.5 GiB (inclusive).

   * ‘lc’: Number of literal context bits.

   * ‘lp’: Number of literal position bits.  The sum ‘lc + lp’ must be
     at most 4.

   * ‘pb’: Number of position bits; must be at most 4.

   * ‘mode’: ‘MODE_FAST’ or ‘MODE_NORMAL’.

   * ‘nice_len’: What should be considered a “nice length” for a match.
     This should be 273 or less.

   * ‘mf’: What match finder to use – ‘MF_HC3’, ‘MF_HC4’, ‘MF_BT2’,
     ‘MF_BT3’, or ‘MF_BT4’.

   * ‘depth’: Maximum search depth used by match finder.  0 (default)
     means to select automatically based on other filter options.

The delta filter stores the differences between bytes, producing more
repetitive input for the compressor in certain circumstances.  It
supports one option, ‘dist’.  This indicates the distance between bytes
to be subtracted.  The default is 1, i.e.  take the differences between
adjacent bytes.

The BCJ filters are intended to be applied to machine code.  They
convert relative branches, calls and jumps in the code to use absolute
addressing, with the aim of increasing the redundancy that can be
exploited by the compressor.  These filters support one option,
‘start_offset’.  This specifies the address that should be mapped to the
beginning of the input data.  The default is 0.


File: python.info,  Node: Examples<8>,  Prev: Specifying custom filter chains,  Up: lzma — Compression using the LZMA algorithm

5.13.4.5 Examples
.................

Reading in a compressed file:

     import lzma
     with lzma.open("file.xz") as f:
         file_content = f.read()

Creating a compressed file:

     import lzma
     data = b"Insert Data Here"
     with lzma.open("file.xz", "w") as f:
         f.write(data)

Compressing data in memory:

     import lzma
     data_in = b"Insert Data Here"
     data_out = lzma.compress(data_in)

Incremental compression:

     import lzma
     lzc = lzma.LZMACompressor()
     out1 = lzc.compress(b"Some data\n")
     out2 = lzc.compress(b"Another piece of data\n")
     out3 = lzc.compress(b"Even more data\n")
     out4 = lzc.flush()
     # Concatenate all the partial results:
     result = b"".join([out1, out2, out3, out4])

Writing compressed data to an already-open file:

     import lzma
     with open("file.xz", "wb") as f:
         f.write(b"This data will not be compressed\n")
         with lzma.open(f, "w") as lzf:
             lzf.write(b"This *will* be compressed\n")
         f.write(b"Not compressed\n")

Creating a compressed file using a custom filter chain:

     import lzma
     my_filters = [
         {"id": lzma.FILTER_DELTA, "dist": 5},
         {"id": lzma.FILTER_LZMA2, "preset": 7 | lzma.PRESET_EXTREME},
     ]
     with lzma.open("file.xz", "w", filters=my_filters) as f:
         f.write(b"blah blah blah")


File: python.info,  Node: zipfile — Work with ZIP archives,  Next: tarfile — Read and write tar archive files,  Prev: lzma — Compression using the LZMA algorithm,  Up: Data Compression and Archiving

5.13.5 ‘zipfile’ — Work with ZIP archives
-----------------------------------------

'Source code:' Lib/zipfile/(1)

__________________________________________________________________

The ZIP file format is a common archive and compression standard.  This
module provides tools to create, read, write, append, and list a ZIP
file.  Any advanced use of this module will require an understanding of
the format, as defined in PKZIP Application Note(2).

This module does not handle multipart ZIP files.  It can handle ZIP
files that use the ZIP64 extensions (that is ZIP files that are more
than 4 GiB in size).  It supports decryption of encrypted files in ZIP
archives, but it cannot create an encrypted file.  Decryption is
extremely slow as it is implemented in native Python rather than C.

The module defines the following items:

 -- Exception: zipfile.BadZipFile

     The error raised for bad ZIP files.

     Added in version 3.2.

 -- Exception: zipfile.BadZipfile

     Alias of *note BadZipFile: 190e, for compatibility with older
     Python versions.

     Deprecated since version 3.2.

 -- Exception: zipfile.LargeZipFile

     The error raised when a ZIP file would require ZIP64 functionality
     but that has not been enabled.

 -- Class: zipfile.ZipFile

     The class for reading and writing ZIP files.  See section *note
     ZipFile objects: 2b95. for constructor details.

 -- Class: zipfile.Path

     Class that implements a subset of the interface provided by *note
     pathlib.Path: 229, including the full *note
     importlib.resources.abc.Traversable: 1f3. interface.

     Added in version 3.8.

 -- Class: zipfile.PyZipFile

     Class for creating ZIP archives containing Python libraries.

 -- Class: zipfile.ZipInfo (filename='NoName', date_time=(1980, 1, 1, 0,
          0, 0))

     Class used to represent information about a member of an archive.
     Instances of this class are returned by the *note getinfo(): 2b96.
     and *note infolist(): 2b97. methods of *note ZipFile: 6c7. objects.
     Most users of the ‘zipfile’ module will not need to create these,
     but only use those created by this module.  'filename' should be
     the full name of the archive member, and 'date_time' should be a
     tuple containing six fields which describe the time of the last
     modification to the file; the fields are described in section *note
     ZipInfo objects: 2b98.

     Changed in version 3.13: A public ‘compress_level’ attribute has
     been added to expose the formerly protected ‘_compresslevel’.  The
     older protected name continues to work as a property for backwards
     compatibility.

 -- Function: zipfile.is_zipfile (filename)

     Returns ‘True’ if 'filename' is a valid ZIP file based on its magic
     number, otherwise returns ‘False’.  'filename' may be a file or
     file-like object too.

     Changed in version 3.1: Support for file and file-like objects.

 -- Data: zipfile.ZIP_STORED

     The numeric constant for an uncompressed archive member.

 -- Data: zipfile.ZIP_DEFLATED

     The numeric constant for the usual ZIP compression method.  This
     requires the *note zlib: 133. module.

 -- Data: zipfile.ZIP_BZIP2

     The numeric constant for the BZIP2 compression method.  This
     requires the *note bz2: 13. module.

     Added in version 3.3.

 -- Data: zipfile.ZIP_LZMA

     The numeric constant for the LZMA compression method.  This
     requires the *note lzma: 8a. module.

     Added in version 3.3.

          Note: The ZIP file format specification has included support
          for bzip2 compression since 2001, and for LZMA compression
          since 2006.  However, some tools (including older Python
          releases) do not support these compression methods, and may
          either refuse to process the ZIP file altogether, or fail to
          extract individual files.

See also
........

PKZIP Application Note(3)

     Documentation on the ZIP file format by Phil Katz, the creator of
     the format and algorithms used.

Info-ZIP Home Page(4)

     Information about the Info-ZIP project’s ZIP archive programs and
     development libraries.

* Menu:

* ZipFile objects::
* Path objects::
* PyZipFile objects::
* ZipInfo objects::
* Command-line interface: Command-line interface<3>.
* Decompression pitfalls::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/zipfile/

   (2) https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT

   (3) https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT

   (4) https://infozip.sourceforge.net/


File: python.info,  Node: ZipFile objects,  Next: Path objects,  Up: zipfile — Work with ZIP archives

5.13.5.1 ZipFile objects
........................

 -- Class: zipfile.ZipFile (file, mode='r', compression=ZIP_STORED,
          allowZip64=True, compresslevel=None, *,
          strict_timestamps=True, metadata_encoding=None)

     Open a ZIP file, where 'file' can be a path to a file (a string), a
     file-like object or a *note path-like object: 2a0.

     The 'mode' parameter should be ‘'r'’ to read an existing file,
     ‘'w'’ to truncate and write a new file, ‘'a'’ to append to an
     existing file, or ‘'x'’ to exclusively create and write a new file.
     If 'mode' is ‘'x'’ and 'file' refers to an existing file, a *note
     FileExistsError: 105b. will be raised.  If 'mode' is ‘'a'’ and
     'file' refers to an existing ZIP file, then additional files are
     added to it.  If 'file' does not refer to a ZIP file, then a new
     ZIP archive is appended to the file.  This is meant for adding a
     ZIP archive to another file (such as ‘python.exe’).  If 'mode' is
     ‘'a'’ and the file does not exist at all, it is created.  If 'mode'
     is ‘'r'’ or ‘'a'’, the file should be seekable.

     'compression' is the ZIP compression method to use when writing the
     archive, and should be *note ZIP_STORED: 2b99, *note ZIP_DEFLATED:
     2b9a, *note ZIP_BZIP2: 2b9b. or *note ZIP_LZMA: 2b9c.; unrecognized
     values will cause *note NotImplementedError: 228. to be raised.  If
     ‘ZIP_DEFLATED’, ‘ZIP_BZIP2’ or ‘ZIP_LZMA’ is specified but the
     corresponding module (*note zlib: 133, *note bz2: 13. or *note
     lzma: 8a.) is not available, *note RuntimeError: 195. is raised.
     The default is ‘ZIP_STORED’.

     If 'allowZip64' is ‘True’ (the default) zipfile will create ZIP
     files that use the ZIP64 extensions when the zipfile is larger than
     4 GiB. If it is ‘false’ ‘zipfile’ will raise an exception when the
     ZIP file would require ZIP64 extensions.

     The 'compresslevel' parameter controls the compression level to use
     when writing files to the archive.  When using *note ZIP_STORED:
     2b99. or *note ZIP_LZMA: 2b9c. it has no effect.  When using *note
     ZIP_DEFLATED: 2b9a. integers ‘0’ through ‘9’ are accepted (see
     *note zlib: 2b32. for more information).  When using *note
     ZIP_BZIP2: 2b9b. integers ‘1’ through ‘9’ are accepted (see *note
     bz2: 86d. for more information).

     The 'strict_timestamps' argument, when set to ‘False’, allows to
     zip files older than 1980-01-01 at the cost of setting the
     timestamp to 1980-01-01.  Similar behavior occurs with files newer
     than 2107-12-31, the timestamp is also set to the limit.

     When mode is ‘'r'’, 'metadata_encoding' may be set to the name of a
     codec, which will be used to decode metadata such as the names of
     members and ZIP comments.

     If the file is created with mode ‘'w'’, ‘'x'’ or ‘'a'’ and then
     *note closed: 2b9e. without adding any files to the archive, the
     appropriate ZIP structures for an empty archive will be written to
     the file.

     ZipFile is also a context manager and therefore supports the *note
     with: 5d5. statement.  In the example, 'myzip' is closed after the
     ‘with’ statement’s suite is finished—even if an exception occurs:

          with ZipFile('spam.zip', 'w') as myzip:
              myzip.write('eggs.txt')

          Note: 'metadata_encoding' is an instance-wide setting for the
          ZipFile.  It is not possible to set this on a per-member
          basis.

          This attribute is a workaround for legacy implementations
          which produce archives with names in the current locale
          encoding or code page (mostly on Windows).  According to the
          .ZIP standard, the encoding of metadata may be specified to be
          either IBM code page (default) or UTF-8 by a flag in the
          archive header.  That flag takes precedence over
          'metadata_encoding', which is a Python-specific extension.

     Changed in version 3.2: Added the ability to use ‘ZipFile’ as a
     context manager.

     Changed in version 3.3: Added support for *note bzip2: 13. and
     *note lzma: 8a. compression.

     Changed in version 3.4: ZIP64 extensions are enabled by default.

     Changed in version 3.5: Added support for writing to unseekable
     streams.  Added support for the ‘'x'’ mode.

     Changed in version 3.6: Previously, a plain *note RuntimeError:
     195. was raised for unrecognized compression values.

     Changed in version 3.6.2: The 'file' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.7: Add the 'compresslevel' parameter.

     Changed in version 3.8: The 'strict_timestamps' keyword-only
     parameter.

     Changed in version 3.11: Added support for specifying member name
     encoding for reading metadata in the zipfile’s directory and file
     headers.

 -- Method: ZipFile.close ()

     Close the archive file.  You must call ‘close()’ before exiting
     your program or essential records will not be written.

 -- Method: ZipFile.getinfo (name)

     Return a *note ZipInfo: d32. object with information about the
     archive member 'name'.  Calling ‘getinfo()’ for a name not
     currently contained in the archive will raise a *note KeyError:
     345.

 -- Method: ZipFile.infolist ()

     Return a list containing a *note ZipInfo: d32. object for each
     member of the archive.  The objects are in the same order as their
     entries in the actual ZIP file on disk if an existing archive was
     opened.

 -- Method: ZipFile.namelist ()

     Return a list of archive members by name.

 -- Method: ZipFile.open (name, mode='r', pwd=None, *,
          force_zip64=False)

     Access a member of the archive as a binary file-like object.
     'name' can be either the name of a file within the archive or a
     *note ZipInfo: d32. object.  The 'mode' parameter, if included,
     must be ‘'r'’ (the default) or ‘'w'’.  'pwd' is the password used
     to decrypt encrypted ZIP files as a *note bytes: 1c2. object.

     ‘open()’ is also a context manager and therefore supports the *note
     with: 5d5. statement:

          with ZipFile('spam.zip') as myzip:
              with myzip.open('eggs.txt') as myfile:
                  print(myfile.read())

     With 'mode' ‘'r'’ the file-like object (‘ZipExtFile’) is read-only
     and provides the following methods: *note read(): 1372, *note
     readline(): 1373, *note readlines(): 24e7, *note seek(): 12d3,
     *note tell(): 13f9, *note __iter__(): 1e62, *note __next__(): 1315.
     These objects can operate independently of the ZipFile.

     With ‘mode='w'’, a writable file handle is returned, which supports
     the *note write(): d02. method.  While a writable file handle is
     open, attempting to read or write other files in the ZIP file will
     raise a *note ValueError: 202.

     In both cases the file-like object has also attributes ‘name’,
     which is equivalent to the name of a file within the archive, and
     ‘mode’, which is ‘'rb'’ or ‘'wb'’ depending on the input mode.

     When writing a file, if the file size is not known in advance but
     may exceed 2 GiB, pass ‘force_zip64=True’ to ensure that the header
     format is capable of supporting large files.  If the file size is
     known in advance, construct a *note ZipInfo: d32. object with *note
     file_size: 2ba0. set, and use that as the 'name' parameter.

          Note: The ‘open()’, *note read(): 2ba1. and *note extract():
          2ba2. methods can take a filename or a *note ZipInfo: d32.
          object.  You will appreciate this when trying to read a ZIP
          file that contains members with duplicate names.

     Changed in version 3.6: Removed support of ‘mode='U'’.  Use *note
     io.TextIOWrapper: 7bf. for reading compressed text files in *note
     universal newlines: d62. mode.

     Changed in version 3.6: ‘ZipFile.open()’ can now be used to write
     files into the archive with the ‘mode='w'’ option.

     Changed in version 3.6: Calling ‘open()’ on a closed ZipFile will
     raise a *note ValueError: 202.  Previously, a *note RuntimeError:
     195. was raised.

     Changed in version 3.13: Added attributes ‘name’ and ‘mode’ for the
     writeable file-like object.  The value of the ‘mode’ attribute for
     the readable file-like object was changed from ‘'r'’ to ‘'rb'’.

 -- Method: ZipFile.extract (member, path=None, pwd=None)

     Extract a member from the archive to the current working directory;
     'member' must be its full name or a *note ZipInfo: d32. object.
     Its file information is extracted as accurately as possible.
     'path' specifies a different directory to extract to.  'member' can
     be a filename or a ‘ZipInfo’ object.  'pwd' is the password used
     for encrypted files as a *note bytes: 1c2. object.

     Returns the normalized path created (a directory or new file).

          Note: If a member filename is an absolute path, a drive/UNC
          sharepoint and leading (back)slashes will be stripped, e.g.:
          ‘///foo/bar’ becomes ‘foo/bar’ on Unix, and ‘C:\foo\bar’
          becomes ‘foo\bar’ on Windows.  And all ‘".."’ components in a
          member filename will be removed, e.g.: ‘../../foo../../ba..r’
          becomes ‘foo../ba..r’.  On Windows illegal characters (‘:’,
          ‘<’, ‘>’, ‘|’, ‘"’, ‘?’, and ‘*’) replaced by underscore
          (‘_’).

     Changed in version 3.6: Calling ‘extract()’ on a closed ZipFile
     will raise a *note ValueError: 202.  Previously, a *note
     RuntimeError: 195. was raised.

     Changed in version 3.6.2: The 'path' parameter accepts a *note
     path-like object: 2a0.

 -- Method: ZipFile.extractall (path=None, members=None, pwd=None)

     Extract all members from the archive to the current working
     directory.  'path' specifies a different directory to extract to.
     'members' is optional and must be a subset of the list returned by
     *note namelist(): 2b9f.  'pwd' is the password used for encrypted
     files as a *note bytes: 1c2. object.

          Warning: Never extract archives from untrusted sources without
          prior inspection.  It is possible that files are created
          outside of 'path', e.g.  members that have absolute filenames
          starting with ‘"/"’ or filenames with two dots ‘".."’.  This
          module attempts to prevent that.  See *note extract(): 2ba2.
          note.

     Changed in version 3.6: Calling ‘extractall()’ on a closed ZipFile
     will raise a *note ValueError: 202.  Previously, a *note
     RuntimeError: 195. was raised.

     Changed in version 3.6.2: The 'path' parameter accepts a *note
     path-like object: 2a0.

 -- Method: ZipFile.printdir ()

     Print a table of contents for the archive to ‘sys.stdout’.

 -- Method: ZipFile.setpassword (pwd)

     Set 'pwd' (a *note bytes: 1c2. object) as default password to
     extract encrypted files.

 -- Method: ZipFile.read (name, pwd=None)

     Return the bytes of the file 'name' in the archive.  'name' is the
     name of the file in the archive, or a *note ZipInfo: d32. object.
     The archive must be open for read or append.  'pwd' is the password
     used for encrypted files as a *note bytes: 1c2. object and, if
     specified, overrides the default password set with *note
     setpassword(): 2ba5.  Calling ‘read()’ on a ZipFile that uses a
     compression method other than *note ZIP_STORED: 2b99, *note
     ZIP_DEFLATED: 2b9a, *note ZIP_BZIP2: 2b9b. or *note ZIP_LZMA: 2b9c.
     will raise a *note NotImplementedError: 228.  An error will also be
     raised if the corresponding compression module is not available.

     Changed in version 3.6: Calling ‘read()’ on a closed ZipFile will
     raise a *note ValueError: 202.  Previously, a *note RuntimeError:
     195. was raised.

 -- Method: ZipFile.testzip ()

     Read all the files in the archive and check their CRC’s and file
     headers.  Return the name of the first bad file, or else return
     ‘None’.

     Changed in version 3.6: Calling ‘testzip()’ on a closed ZipFile
     will raise a *note ValueError: 202.  Previously, a *note
     RuntimeError: 195. was raised.

 -- Method: ZipFile.write (filename, arcname=None, compress_type=None,
          compresslevel=None)

     Write the file named 'filename' to the archive, giving it the
     archive name 'arcname' (by default, this will be the same as
     'filename', but without a drive letter and with leading path
     separators removed).  If given, 'compress_type' overrides the value
     given for the 'compression' parameter to the constructor for the
     new entry.  Similarly, 'compresslevel' will override the
     constructor if given.  The archive must be open with mode ‘'w'’,
     ‘'x'’ or ‘'a'’.

          Note: The ZIP file standard historically did not specify a
          metadata encoding, but strongly recommended CP437 (the
          original IBM PC encoding) for interoperability.  Recent
          versions allow use of UTF-8 (only).  In this module, UTF-8
          will automatically be used to write the member names if they
          contain any non-ASCII characters.  It is not possible to write
          member names in any encoding other than ASCII or UTF-8.

          Note: Archive names should be relative to the archive root,
          that is, they should not start with a path separator.

          Note: If ‘arcname’ (or ‘filename’, if ‘arcname’ is not given)
          contains a null byte, the name of the file in the archive will
          be truncated at the null byte.

          Note: A leading slash in the filename may lead to the archive
          being impossible to open in some zip programs on Windows
          systems.

     Changed in version 3.6: Calling ‘write()’ on a ZipFile created with
     mode ‘'r'’ or a closed ZipFile will raise a *note ValueError: 202.
     Previously, a *note RuntimeError: 195. was raised.

 -- Method: ZipFile.writestr (zinfo_or_arcname, data,
          compress_type=None, compresslevel=None)

     Write a file into the archive.  The contents is 'data', which may
     be either a *note str: 44f. or a *note bytes: 1c2. instance; if it
     is a ‘str’, it is encoded as UTF-8 first.  'zinfo_or_arcname' is
     either the file name it will be given in the archive, or a *note
     ZipInfo: d32. instance.  If it’s an instance, at least the
     filename, date, and time must be given.  If it’s a name, the date
     and time is set to the current date and time.  The archive must be
     opened with mode ‘'w'’, ‘'x'’ or ‘'a'’.

     If given, 'compress_type' overrides the value given for the
     'compression' parameter to the constructor for the new entry, or in
     the 'zinfo_or_arcname' (if that is a *note ZipInfo: d32. instance).
     Similarly, 'compresslevel' will override the constructor if given.

          Note: When passing a *note ZipInfo: d32. instance as the
          'zinfo_or_arcname' parameter, the compression method used will
          be that specified in the 'compress_type' member of the given
          ‘ZipInfo’ instance.  By default, the ‘ZipInfo’ constructor
          sets this member to *note ZIP_STORED: 2b99.

     Changed in version 3.2: The 'compress_type' argument.

     Changed in version 3.6: Calling ‘writestr()’ on a ZipFile created
     with mode ‘'r'’ or a closed ZipFile will raise a *note ValueError:
     202.  Previously, a *note RuntimeError: 195. was raised.

 -- Method: ZipFile.mkdir (zinfo_or_directory, mode=511)

     Create a directory inside the archive.  If 'zinfo_or_directory' is
     a string, a directory is created inside the archive with the mode
     that is specified in the 'mode' argument.  If, however,
     'zinfo_or_directory' is a *note ZipInfo: d32. instance then the
     'mode' argument is ignored.

     The archive must be opened with mode ‘'w'’, ‘'x'’ or ‘'a'’.

     Added in version 3.11.

The following data attributes are also available:

 -- Attribute: ZipFile.filename

     Name of the ZIP file.

 -- Attribute: ZipFile.debug

     The level of debug output to use.  This may be set from ‘0’ (the
     default, no output) to ‘3’ (the most output).  Debugging
     information is written to ‘sys.stdout’.

 -- Attribute: ZipFile.comment

     The comment associated with the ZIP file as a *note bytes: 1c2.
     object.  If assigning a comment to a *note ZipFile: 6c7. instance
     created with mode ‘'w'’, ‘'x'’ or ‘'a'’, it should be no longer
     than 65535 bytes.  Comments longer than this will be truncated.


File: python.info,  Node: Path objects,  Next: PyZipFile objects,  Prev: ZipFile objects,  Up: zipfile — Work with ZIP archives

5.13.5.2 Path objects
.....................

 -- Class: zipfile.Path (root, at='')

     Construct a Path object from a ‘root’ zipfile (which may be a *note
     ZipFile: 6c7. instance or ‘file’ suitable for passing to the
     ‘ZipFile’ constructor).

     ‘at’ specifies the location of this Path within the zipfile, e.g.
     ‘dir/file.txt’, ‘dir/’, or ‘’.  Defaults to the empty string,
     indicating the root.

          Note: The ‘Path’ class does not sanitize filenames within the
          ZIP archive.  Unlike the *note ZipFile.extract(): 2ba2. and
          *note ZipFile.extractall(): 2ba3. methods, it is the caller’s
          responsibility to validate or sanitize filenames to prevent
          path traversal vulnerabilities (e.g., filenames containing
          “..” or absolute paths).  When handling untrusted archives,
          consider resolving filenames using *note os.path.abspath():
          1364. and checking against the target directory with *note
          os.path.commonpath(): e70.

Path objects expose the following features of *note pathlib.Path: 229.
objects:

Path objects are traversable using the ‘/’ operator or ‘joinpath’.

 -- Attribute: Path.name

     The final path component.

 -- Method: Path.open (mode='r', *, pwd, **)

     Invoke *note ZipFile.open(): 41e. on the current path.  Allows
     opening for read or write, text or binary through supported modes:
     ‘r’, ‘w’, ‘rb’, ‘wb’.  Positional and keyword arguments are passed
     through to *note io.TextIOWrapper: 7bf. when opened as text and
     ignored otherwise.  ‘pwd’ is the ‘pwd’ parameter to
     ‘ZipFile.open()’.

     Changed in version 3.9: Added support for text and binary modes for
     open.  Default mode is now text.

     Changed in version 3.11.2: The ‘encoding’ parameter can be supplied
     as a positional argument without causing a *note TypeError: 2c3.
     As it could in 3.9.  Code needing to be compatible with unpatched
     3.10 and 3.11 versions must pass all *note io.TextIOWrapper: 7bf.
     arguments, ‘encoding’ included, as keywords.

 -- Method: Path.iterdir ()

     Enumerate the children of the current directory.

 -- Method: Path.is_dir ()

     Return ‘True’ if the current context references a directory.

 -- Method: Path.is_file ()

     Return ‘True’ if the current context references a file.

 -- Method: Path.is_symlink ()

     Return ‘True’ if the current context references a symbolic link.

     Added in version 3.12.

     Changed in version 3.13: Previously, ‘is_symlink’ would
     unconditionally return ‘False’.

 -- Method: Path.exists ()

     Return ‘True’ if the current context references a file or directory
     in the zip file.

 -- Data: Path.suffix

     The last dot-separated portion of the final component, if any.
     This is commonly called the file extension.

     Added in version 3.11: Added ‘Path.suffix’ property.

 -- Data: Path.stem

     The final path component, without its suffix.

     Added in version 3.11: Added ‘Path.stem’ property.

 -- Data: Path.suffixes

     A list of the path’s suffixes, commonly called file extensions.

     Added in version 3.11: Added ‘Path.suffixes’ property.

 -- Method: Path.read_text (*, **)

     Read the current file as unicode text.  Positional and keyword
     arguments are passed through to *note io.TextIOWrapper: 7bf.
     (except ‘buffer’, which is implied by the context).

     Changed in version 3.11.2: The ‘encoding’ parameter can be supplied
     as a positional argument without causing a *note TypeError: 2c3.
     As it could in 3.9.  Code needing to be compatible with unpatched
     3.10 and 3.11 versions must pass all *note io.TextIOWrapper: 7bf.
     arguments, ‘encoding’ included, as keywords.

 -- Method: Path.read_bytes ()

     Read the current file as bytes.

 -- Method: Path.joinpath (*other)

     Return a new Path object with each of the 'other' arguments joined.
     The following are equivalent:

          >>> Path(...).joinpath('child').joinpath('grandchild')
          >>> Path(...).joinpath('child', 'grandchild')
          >>> Path(...) / 'child' / 'grandchild'

     Changed in version 3.10: Prior to 3.10, ‘joinpath’ was undocumented
     and accepted exactly one parameter.

The zipp(1) project provides backports of the latest path object
functionality to older Pythons.  Use ‘zipp.Path’ in place of
‘zipfile.Path’ for early access to changes.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/zipp/


File: python.info,  Node: PyZipFile objects,  Next: ZipInfo objects,  Prev: Path objects,  Up: zipfile — Work with ZIP archives

5.13.5.3 PyZipFile objects
..........................

The *note PyZipFile: 1034. constructor takes the same parameters as the
*note ZipFile: 6c7. constructor, and one additional parameter,
'optimize'.

 -- Class: zipfile.PyZipFile (file, mode='r', compression=ZIP_STORED,
          allowZip64=True, optimize=-1)

     Changed in version 3.2: Added the 'optimize' parameter.

     Changed in version 3.4: ZIP64 extensions are enabled by default.

     Instances have one method in addition to those of *note ZipFile:
     6c7. objects:

      -- Method: writepy (pathname, basename='', filterfunc=None)

          Search for files ‘*.py’ and add the corresponding file to the
          archive.

          If the 'optimize' parameter to ‘PyZipFile’ was not given or
          ‘-1’, the corresponding file is a ‘*.pyc’ file, compiling if
          necessary.

          If the 'optimize' parameter to ‘PyZipFile’ was ‘0’, ‘1’ or
          ‘2’, only files with that optimization level (see *note
          compile(): 192.) are added to the archive, compiling if
          necessary.

          If 'pathname' is a file, the filename must end with ‘.py’, and
          just the (corresponding ‘*.pyc’) file is added at the top
          level (no path information).  If 'pathname' is a file that
          does not end with ‘.py’, a *note RuntimeError: 195. will be
          raised.  If it is a directory, and the directory is not a
          package directory, then all the files ‘*.pyc’ are added at the
          top level.  If the directory is a package directory, then all
          ‘*.pyc’ are added under the package name as a file path, and
          if any subdirectories are package directories, all of these
          are added recursively in sorted order.

          'basename' is intended for internal use only.

          'filterfunc', if given, must be a function taking a single
          string argument.  It will be passed each path (including each
          individual full file path) before it is added to the archive.
          If 'filterfunc' returns a false value, the path will not be
          added, and if it is a directory its contents will be ignored.
          For example, if our test files are all either in ‘test’
          directories or start with the string ‘test_’, we can use a
          'filterfunc' to exclude them:

               >>> zf = PyZipFile('myprog.zip')
               >>> def notests(s):
               ...     fn = os.path.basename(s)
               ...     return (not (fn == 'test' or fn.startswith('test_')))
               ...
               >>> zf.writepy('myprog', filterfunc=notests)

          The ‘writepy()’ method makes archives with file names like
          this:

               string.pyc                   # Top level name
               test/__init__.pyc            # Package directory
               test/testall.pyc             # Module test.testall
               test/bogus/__init__.pyc      # Subpackage directory
               test/bogus/myfile.pyc        # Submodule test.bogus.myfile

          Changed in version 3.4: Added the 'filterfunc' parameter.

          Changed in version 3.6.2: The 'pathname' parameter accepts a
          *note path-like object: 2a0.

          Changed in version 3.7: Recursion sorts directory entries.


File: python.info,  Node: ZipInfo objects,  Next: Command-line interface<3>,  Prev: PyZipFile objects,  Up: zipfile — Work with ZIP archives

5.13.5.4 ZipInfo objects
........................

Instances of the *note ZipInfo: d32. class are returned by the *note
getinfo(): 2b96. and *note infolist(): 2b97. methods of *note ZipFile:
6c7. objects.  Each object stores information about a single member of
the ZIP archive.

There is one classmethod to make a *note ZipInfo: d32. instance for a
filesystem file:

 -- Method: classmethod ZipInfo.from_file (filename, arcname=None, *,
          strict_timestamps=True)

     Construct a *note ZipInfo: d32. instance for a file on the
     filesystem, in preparation for adding it to a zip file.

     'filename' should be the path to a file or directory on the
     filesystem.

     If 'arcname' is specified, it is used as the name within the
     archive.  If 'arcname' is not specified, the name will be the same
     as 'filename', but with any drive letter and leading path
     separators removed.

     The 'strict_timestamps' argument, when set to ‘False’, allows to
     zip files older than 1980-01-01 at the cost of setting the
     timestamp to 1980-01-01.  Similar behavior occurs with files newer
     than 2107-12-31, the timestamp is also set to the limit.

     Added in version 3.6.

     Changed in version 3.6.2: The 'filename' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.8: Added the 'strict_timestamps' keyword-only
     parameter.

Instances have the following methods and attributes:

 -- Method: ZipInfo.is_dir ()

     Return ‘True’ if this archive member is a directory.

     This uses the entry’s name: directories should always end with ‘/’.

     Added in version 3.6.

 -- Attribute: ZipInfo.filename

     Name of the file in the archive.

 -- Attribute: ZipInfo.date_time

     The time and date of the last modification to the archive member.
     This is a tuple of six values representing the “last [modified]
     file time” and “last [modified] file date” fields from the ZIP
     file’s central directory.

     The tuple contains:

     Index       Value
                 
     -------------------------------------------
                 
     ‘0’         Year (>= 1980)
                 
                 
     ‘1’         Month (one-based)
                 
                 
     ‘2’         Day of month (one-based)
                 
                 
     ‘3’         Hours (zero-based)
                 
                 
     ‘4’         Minutes (zero-based)
                 
                 
     ‘5’         Seconds (zero-based)
                 

          Note: The ZIP format supports multiple timestamp fields in
          different locations (central directory, extra fields for
          NTFS/UNIX systems, etc.).  This attribute specifically returns
          the timestamp from the central directory.  The central
          directory timestamp format in ZIP files does not support
          timestamps before 1980.  While some extra field formats (such
          as UNIX timestamps) can represent earlier dates, this
          attribute only returns the central directory timestamp.

          The central directory timestamp is interpreted as representing
          local time, rather than UTC time, to match the behavior of
          other zip tools.

 -- Attribute: ZipInfo.compress_type

     Type of compression for the archive member.

 -- Attribute: ZipInfo.comment

     Comment for the individual archive member as a *note bytes: 1c2.
     object.

 -- Attribute: ZipInfo.extra

     Expansion field data.  The PKZIP Application Note(1) contains some
     comments on the internal structure of the data contained in this
     *note bytes: 1c2. object.

 -- Attribute: ZipInfo.create_system

     System which created ZIP archive.

 -- Attribute: ZipInfo.create_version

     PKZIP version which created ZIP archive.

 -- Attribute: ZipInfo.extract_version

     PKZIP version needed to extract archive.

 -- Attribute: ZipInfo.reserved

     Must be zero.

 -- Attribute: ZipInfo.flag_bits

     ZIP flag bits.

 -- Attribute: ZipInfo.volume

     Volume number of file header.

 -- Attribute: ZipInfo.internal_attr

     Internal attributes.

 -- Attribute: ZipInfo.external_attr

     External file attributes.

 -- Attribute: ZipInfo.header_offset

     Byte offset to the file header.

 -- Attribute: ZipInfo.CRC

     CRC-32 of the uncompressed file.

 -- Attribute: ZipInfo.compress_size

     Size of the compressed data.

 -- Attribute: ZipInfo.file_size

     Size of the uncompressed file.

   ---------- Footnotes ----------

   (1) https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT


File: python.info,  Node: Command-line interface<3>,  Next: Decompression pitfalls,  Prev: ZipInfo objects,  Up: zipfile — Work with ZIP archives

5.13.5.5 Command-line interface
...............................

The ‘zipfile’ module provides a simple command-line interface to
interact with ZIP archives.

If you want to create a new ZIP archive, specify its name after the
*note -c: 2bc9. option and then list the filename(s) that should be
included:

     $ python -m zipfile -c monty.zip spam.txt eggs.txt

Passing a directory is also acceptable:

     $ python -m zipfile -c monty.zip life-of-brian_1979/

If you want to extract a ZIP archive into the specified directory, use
the *note -e: 2bca. option:

     $ python -m zipfile -e monty.zip target-dir/

For a list of the files in a ZIP archive, use the *note -l: 2bcb.
option:

     $ python -m zipfile -l monty.zip

* Menu:

* Command-line options: Command-line options<2>.


File: python.info,  Node: Command-line options<2>,  Up: Command-line interface<3>

5.13.5.6 Command-line options
.............................

 -- Option: -l <zipfile>
 -- Option: --list <zipfile>

     List files in a zipfile.

 -- Option: -c <zipfile> <source1> ... <sourceN>
 -- Option: --create <zipfile> <source1> ... <sourceN>

     Create zipfile from source files.

 -- Option: -e <zipfile> <output_dir>
 -- Option: --extract <zipfile> <output_dir>

     Extract zipfile into target directory.

 -- Option: -t <zipfile>
 -- Option: --test <zipfile>

     Test whether the zipfile is valid or not.

 -- Option: --metadata-encoding <encoding>

     Specify encoding of member names for *note -l: 2bcb, *note -e:
     2bca. and *note -t: 2bd0.

     Added in version 3.11.


File: python.info,  Node: Decompression pitfalls,  Prev: Command-line interface<3>,  Up: zipfile — Work with ZIP archives

5.13.5.7 Decompression pitfalls
...............................

The extraction in zipfile module might fail due to some pitfalls listed
below.

* Menu:

* From file itself::
* File system limitations::
* Resources limitations::
* Interruption::
* Default behaviors of extraction::


File: python.info,  Node: From file itself,  Next: File system limitations,  Up: Decompression pitfalls

5.13.5.8 From file itself
.........................

Decompression may fail due to incorrect password / CRC checksum / ZIP
format or unsupported compression method / decryption.


File: python.info,  Node: File system limitations,  Next: Resources limitations,  Prev: From file itself,  Up: Decompression pitfalls

5.13.5.9 File system limitations
................................

Exceeding limitations on different file systems can cause decompression
failed.  Such as allowable characters in the directory entries, length
of the file name, length of the pathname, size of a single file, and
number of files, etc.


File: python.info,  Node: Resources limitations,  Next: Interruption,  Prev: File system limitations,  Up: Decompression pitfalls

5.13.5.10 Resources limitations
...............................

The lack of memory or disk volume would lead to decompression failed.
For example, decompression bombs (aka ZIP bomb(1)) apply to zipfile
library that can cause disk volume exhaustion.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Zip_bomb


File: python.info,  Node: Interruption,  Next: Default behaviors of extraction,  Prev: Resources limitations,  Up: Decompression pitfalls

5.13.5.11 Interruption
......................

Interruption during the decompression, such as pressing control-C or
killing the decompression process may result in incomplete decompression
of the archive.


File: python.info,  Node: Default behaviors of extraction,  Prev: Interruption,  Up: Decompression pitfalls

5.13.5.12 Default behaviors of extraction
.........................................

Not knowing the default extraction behaviors can cause unexpected
decompression results.  For example, when extracting the same archive
twice, it overwrites files without asking.


File: python.info,  Node: tarfile — Read and write tar archive files,  Prev: zipfile — Work with ZIP archives,  Up: Data Compression and Archiving

5.13.6 ‘tarfile’ — Read and write tar archive files
---------------------------------------------------

'Source code:' Lib/tarfile.py(1)

__________________________________________________________________

The ‘tarfile’ module makes it possible to read and write tar archives,
including those using gzip, bz2 and lzma compression.  Use the *note
zipfile: 131. module to read or write ‘.zip’ files, or the higher-level
functions in *note shutil: 125e.

Some facts and figures:

   * reads and writes *note gzip: 67, *note bz2: 13. and *note lzma: 8a.
     compressed archives if the respective modules are available.

   * read/write support for the POSIX.1-1988 (ustar) format.

   * read/write support for the GNU tar format including 'longname' and
     'longlink' extensions, read-only support for all variants of the
     'sparse' extension including restoration of sparse files.

   * read/write support for the POSIX.1-2001 (pax) format.

   * handles directories, regular files, hardlinks, symbolic links,
     fifos, character devices and block devices and is able to acquire
     and restore file information like timestamp, access permissions and
     owner.

Changed in version 3.3: Added support for *note lzma: 8a. compression.

Changed in version 3.12: Archives are extracted using a *note filter:
46f, which makes it possible to either limit surprising/dangerous
features, or to acknowledge that they are expected and the archive is
fully trusted.  By default, archives are fully trusted, but this default
is deprecated and slated to change in Python 3.14.

 -- Function: tarfile.open (name=None, mode='r', fileobj=None,
          bufsize=10240, **kwargs)

     Return a *note TarFile: 1255. object for the pathname 'name'.  For
     detailed information on ‘TarFile’ objects and the keyword arguments
     that are allowed, see *note TarFile Objects: 2bdd.

     'mode' has to be a string of the form ‘'filemode[:compression]'’,
     it defaults to ‘'r'’.  Here is a full list of mode combinations:

     mode                   action
                            
     -------------------------------------------------------------------------
                            
     ‘'r'’ or ‘'r:*'’       Open for reading with transparent compression
                            (recommended).
                            
                            
     ‘'r:'’                 Open for reading exclusively without
                            compression.
                            
                            
     ‘'r:gz'’               Open for reading with gzip compression.
                            
                            
     ‘'r:bz2'’              Open for reading with bzip2 compression.
                            
                            
     ‘'r:xz'’               Open for reading with lzma compression.
                            
                            
     ‘'x'’ or ‘'x:'’        Create a tarfile exclusively without
                            compression.  Raise a
                            *note FileExistsError: 105b. exception if it
                            already exists.
                            
                            
     ‘'x:gz'’               Create a tarfile with gzip compression.  Raise
                            a *note FileExistsError: 105b. exception if it
                            already exists.
                            
                            
     ‘'x:bz2'’              Create a tarfile with bzip2 compression.  Raise
                            a *note FileExistsError: 105b. exception if it
                            already exists.
                            
                            
     ‘'x:xz'’               Create a tarfile with lzma compression.  Raise
                            a *note FileExistsError: 105b. exception if it
                            already exists.
                            
                            
     ‘'a'’ or ‘'a:'’        Open for appending with no compression.  The
                            file is created if it does not exist.
                            
                            
     ‘'w'’ or ‘'w:'’        Open for uncompressed writing.
                            
                            
     ‘'w:gz'’               Open for gzip compressed writing.
                            
                            
     ‘'w:bz2'’              Open for bzip2 compressed writing.
                            
                            
     ‘'w:xz'’               Open for lzma compressed writing.
                            

     Note that ‘'a:gz'’, ‘'a:bz2'’ or ‘'a:xz'’ is not possible.  If
     'mode' is not suitable to open a certain (compressed) file for
     reading, *note ReadError: 19f5. is raised.  Use 'mode' ‘'r'’ to
     avoid this.  If a compression method is not supported, *note
     CompressionError: 2bde. is raised.

     If 'fileobj' is specified, it is used as an alternative to a *note
     file object: 1208. opened in binary mode for 'name'.  It is
     supposed to be at position 0.

     For modes ‘'w:gz'’, ‘'x:gz'’, ‘'w|gz'’, ‘'w:bz2'’, ‘'x:bz2'’,
     ‘'w|bz2'’, *note tarfile.open(): eab. accepts the keyword argument
     'compresslevel' (default ‘9’) to specify the compression level of
     the file.

     For modes ‘'w:xz'’ and ‘'x:xz'’, *note tarfile.open(): eab. accepts
     the keyword argument 'preset' to specify the compression level of
     the file.

     For special purposes, there is a second format for 'mode':
     ‘'filemode|[compression]'’.  *note tarfile.open(): eab. will return
     a *note TarFile: 1255. object that processes its data as a stream
     of blocks.  No random seeking will be done on the file.  If given,
     'fileobj' may be any object that has a *note read(): e4e. or *note
     write(): 13f8. method (depending on the 'mode') that works with
     bytes.  'bufsize' specifies the blocksize and defaults to ‘20 *
     512’ bytes.  Use this variant in combination with e.g.
     ‘sys.stdin.buffer’, a socket *note file object: 1208. or a tape
     device.  However, such a ‘TarFile’ object is limited in that it
     does not allow random access, see *note Examples: 2bdf.  The
     currently possible modes:

     Mode              Action
                       
     -------------------------------------------------------------------
                       
     ‘'r|*'’           Open a 'stream' of tar blocks for reading with
                       transparent compression.
                       
                       
     ‘'r|'’            Open a 'stream' of uncompressed tar blocks for
                       reading.
                       
                       
     ‘'r|gz'’          Open a gzip compressed 'stream' for reading.
                       
                       
     ‘'r|bz2'’         Open a bzip2 compressed 'stream' for reading.
                       
                       
     ‘'r|xz'’          Open an lzma compressed 'stream' for reading.
                       
                       
     ‘'w|'’            Open an uncompressed 'stream' for writing.
                       
                       
     ‘'w|gz'’          Open a gzip compressed 'stream' for writing.
                       
                       
     ‘'w|bz2'’         Open a bzip2 compressed 'stream' for writing.
                       
                       
     ‘'w|xz'’          Open an lzma compressed 'stream' for writing.
                       

     Changed in version 3.5: The ‘'x'’ (exclusive creation) mode was
     added.

     Changed in version 3.6: The 'name' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.12: The 'compresslevel' keyword argument also
     works for streams.

 -- Class: tarfile.TarFile

     Class for reading and writing tar archives.  Do not use this class
     directly: use *note tarfile.open(): eab. instead.  See *note
     TarFile Objects: 2bdd.

 -- Function: tarfile.is_tarfile (name)

     Return *note True: c2d. if 'name' is a tar archive file, that the
     ‘tarfile’ module can read.  'name' may be a *note str: 44f, file,
     or file-like object.

     Changed in version 3.9: Support for file and file-like objects.

The ‘tarfile’ module defines the following exceptions:

 -- Exception: tarfile.TarError

     Base class for all ‘tarfile’ exceptions.

 -- Exception: tarfile.ReadError

     Is raised when a tar archive is opened, that either cannot be
     handled by the ‘tarfile’ module or is somehow invalid.

 -- Exception: tarfile.CompressionError

     Is raised when a compression method is not supported or when the
     data cannot be decoded properly.

 -- Exception: tarfile.StreamError

     Is raised for the limitations that are typical for stream-like
     *note TarFile: 1255. objects.

 -- Exception: tarfile.ExtractError

     Is raised for 'non-fatal' errors when using *note
     TarFile.extract(): 432, but only if *note TarFile.errorlevel:
     434.‘== 2’.

 -- Exception: tarfile.HeaderError

     Is raised by *note TarInfo.frombuf(): 2be4. if the buffer it gets
     is invalid.

 -- Exception: tarfile.FilterError

     Base class for members *note refused: 2be6. by filters.

      -- Attribute: tarinfo

          Information about the member that the filter refused to
          extract, as *note TarInfo: 2be8.

 -- Exception: tarfile.AbsolutePathError

     Raised to refuse extracting a member with an absolute path.

 -- Exception: tarfile.OutsideDestinationError

     Raised to refuse extracting a member outside the destination
     directory.

 -- Exception: tarfile.SpecialFileError

     Raised to refuse extracting a special file (e.g.  a device or
     pipe).

 -- Exception: tarfile.AbsoluteLinkError

     Raised to refuse extracting a symbolic link with an absolute path.

 -- Exception: tarfile.LinkOutsideDestinationError

     Raised to refuse extracting a symbolic link pointing outside the
     destination directory.

 -- Exception: tarfile.LinkFallbackError

     Raised to refuse emulating a link (hard or symbolic) by extracting
     another archive member, when that member would be rejected by the
     filter location.  The exception that was raised to reject the
     replacement member is available as ‘BaseException.__context__’.

     Added in version 3.13.4.

The following constants are available at the module level:

 -- Data: tarfile.ENCODING

     The default character encoding: ‘'utf-8'’ on Windows, the value
     returned by *note sys.getfilesystemencoding(): c7a. otherwise.

 -- Data: tarfile.REGTYPE
 -- Data: tarfile.AREGTYPE

     A regular file *note type: 2bf1.

 -- Data: tarfile.LNKTYPE

     A link (inside tarfile) *note type: 2bf1.

 -- Data: tarfile.SYMTYPE

     A symbolic link *note type: 2bf1.

 -- Data: tarfile.CHRTYPE

     A character special device *note type: 2bf1.

 -- Data: tarfile.BLKTYPE

     A block special device *note type: 2bf1.

 -- Data: tarfile.DIRTYPE

     A directory *note type: 2bf1.

 -- Data: tarfile.FIFOTYPE

     A FIFO special device *note type: 2bf1.

 -- Data: tarfile.CONTTYPE

     A contiguous file *note type: 2bf1.

 -- Data: tarfile.GNUTYPE_LONGNAME

     A GNU tar longname *note type: 2bf1.

 -- Data: tarfile.GNUTYPE_LONGLINK

     A GNU tar longlink *note type: 2bf1.

 -- Data: tarfile.GNUTYPE_SPARSE

     A GNU tar sparse file *note type: 2bf1.

Each of the following constants defines a tar archive format that the
‘tarfile’ module is able to create.  See section *note Supported tar
formats: 2bfc. for details.

 -- Data: tarfile.USTAR_FORMAT

     POSIX.1-1988 (ustar) format.

 -- Data: tarfile.GNU_FORMAT

     GNU tar format.

 -- Data: tarfile.PAX_FORMAT

     POSIX.1-2001 (pax) format.

 -- Data: tarfile.DEFAULT_FORMAT

     The default format for creating archives.  This is currently *note
     PAX_FORMAT: 2bff.

     Changed in version 3.8: The default format for new archives was
     changed to *note PAX_FORMAT: 2bff. from *note GNU_FORMAT: 2bfe.

See also
........

Module *note zipfile: 131.

     Documentation of the *note zipfile: 131. standard module.

*note Archiving operations: 125e.

     Documentation of the higher-level archiving facilities provided by
     the standard *note shutil: c5. module.

GNU tar manual, Basic Tar Format(2)

     Documentation for tar archive files, including GNU tar extensions.

* Menu:

* TarFile Objects::
* TarInfo Objects::
* Extraction filters::
* Command-Line Interface::
* Examples: Examples<9>.
* Supported tar formats::
* Unicode issues::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tarfile.py

   (2) https://www.gnu.org/software/tar/manual/html_node/Standard.html


File: python.info,  Node: TarFile Objects,  Next: TarInfo Objects,  Up: tarfile — Read and write tar archive files

5.13.6.1 TarFile Objects
........................

The *note TarFile: 1255. object provides an interface to a tar archive.
A tar archive is a sequence of blocks.  An archive member (a stored
file) is made up of a header block followed by data blocks.  It is
possible to store a file in a tar archive several times.  Each archive
member is represented by a *note TarInfo: 1256. object, see *note
TarInfo Objects: 2be8. for details.

A *note TarFile: 1255. object can be used as a context manager in a
*note with: 5d5. statement.  It will automatically be closed when the
block is completed.  Please note that in the event of an exception an
archive opened for writing will not be finalized; only the internally
used file object will be closed.  See the *note Examples: 2bdf. section
for a use case.

Added in version 3.2: Added support for the context management protocol.

 -- Class: tarfile.TarFile (name=None, mode='r', fileobj=None,
          format=DEFAULT_FORMAT, tarinfo=TarInfo, dereference=False,
          ignore_zeros=False, encoding=ENCODING,
          errors='surrogateescape', pax_headers=None, debug=0,
          errorlevel=1, stream=False)

     All following arguments are optional and can be accessed as
     instance attributes as well.

     'name' is the pathname of the archive.  'name' may be a *note
     path-like object: 2a0.  It can be omitted if 'fileobj' is given.
     In this case, the file object’s ‘name’ attribute is used if it
     exists.

     'mode' is either ‘'r'’ to read from an existing archive, ‘'a'’ to
     append data to an existing file, ‘'w'’ to create a new file
     overwriting an existing one, or ‘'x'’ to create a new file only if
     it does not already exist.

     If 'fileobj' is given, it is used for reading or writing data.  If
     it can be determined, 'mode' is overridden by 'fileobj'’s mode.
     'fileobj' will be used from position 0.

          Note: 'fileobj' is not closed, when ‘TarFile’ is closed.

     'format' controls the archive format for writing.  It must be one
     of the constants *note USTAR_FORMAT: 2bfd, *note GNU_FORMAT: 2bfe.
     or *note PAX_FORMAT: 2bff. that are defined at module level.  When
     reading, format will be automatically detected, even if different
     formats are present in a single archive.

     The 'tarinfo' argument can be used to replace the default *note
     TarInfo: 1256. class with a different one.

     If 'dereference' is *note False: b4f, add symbolic and hard links
     to the archive.  If it is *note True: c2d, add the content of the
     target files to the archive.  This has no effect on systems that do
     not support symbolic links.

     If 'ignore_zeros' is *note False: b4f, treat an empty block as the
     end of the archive.  If it is *note True: c2d, skip empty (and
     invalid) blocks and try to get as many members as possible.  This
     is only useful for reading concatenated or damaged archives.

     'debug' can be set from ‘0’ (no debug messages) up to ‘3’ (all
     debug messages).  The messages are written to ‘sys.stderr’.

     'errorlevel' controls how extraction errors are handled, see *note
     the corresponding attribute: 434.

     The 'encoding' and 'errors' arguments define the character encoding
     to be used for reading or writing the archive and how conversion
     errors are going to be handled.  The default settings will work for
     most users.  See section *note Unicode issues: 2c02. for in-depth
     information.

     The 'pax_headers' argument is an optional dictionary of strings
     which will be added as a pax global header if 'format' is *note
     PAX_FORMAT: 2bff.

     If 'stream' is set to *note True: c2d. then while reading the
     archive info about files in the archive are not cached, saving
     memory.

     Changed in version 3.2: Use ‘'surrogateescape'’ as the default for
     the 'errors' argument.

     Changed in version 3.5: The ‘'x'’ (exclusive creation) mode was
     added.

     Changed in version 3.6: The 'name' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.13: Add the 'stream' parameter.

 -- Method: classmethod TarFile.open (...)

     Alternative constructor.  The *note tarfile.open(): eab. function
     is actually a shortcut to this classmethod.

 -- Method: TarFile.getmember (name)

     Return a *note TarInfo: 1256. object for member 'name'.  If 'name'
     can not be found in the archive, *note KeyError: 345. is raised.

          Note: If a member occurs more than once in the archive, its
          last occurrence is assumed to be the most up-to-date version.

 -- Method: TarFile.getmembers ()

     Return the members of the archive as a list of *note TarInfo: 1256.
     objects.  The list has the same order as the members in the
     archive.

 -- Method: TarFile.getnames ()

     Return the members as a list of their names.  It has the same order
     as the list returned by *note getmembers(): ead.

 -- Method: TarFile.list (verbose=True, *, members=None)

     Print a table of contents to ‘sys.stdout’.  If 'verbose' is *note
     False: b4f, only the names of the members are printed.  If it is
     *note True: c2d, output similar to that of ‘ls -l’ is produced.  If
     optional 'members' is given, it must be a subset of the list
     returned by *note getmembers(): ead.

     Changed in version 3.5: Added the 'members' parameter.

 -- Method: TarFile.next ()

     Return the next member of the archive as a *note TarInfo: 1256.
     object, when *note TarFile: 1255. is opened for reading.  Return
     *note None: 678. if there is no more available.

 -- Method: TarFile.extractall (path='.', members=None, *,
          numeric_owner=False, filter=None)

     Extract all members from the archive to the current working
     directory or directory 'path'.  If optional 'members' is given, it
     must be a subset of the list returned by *note getmembers(): ead.
     Directory information like owner, modification time and permissions
     are set after all members have been extracted.  This is done to
     work around two problems: A directory’s modification time is reset
     each time a file is created in it.  And, if a directory’s
     permissions do not allow writing, extracting files to it will fail.

     If 'numeric_owner' is *note True: c2d, the uid and gid numbers from
     the tarfile are used to set the owner/group for the extracted
     files.  Otherwise, the named values from the tarfile are used.

     The 'filter' argument specifies how ‘members’ are modified or
     rejected before extraction.  See *note Extraction filters: 46f. for
     details.  It is recommended to set this explicitly depending on
     which 'tar' features you need to support.

          Warning: Never extract archives from untrusted sources without
          prior inspection.  It is possible that files are created
          outside of 'path', e.g.  members that have absolute filenames
          starting with ‘"/"’ or filenames with two dots ‘".."’.

          Set ‘filter='data'’ to prevent the most dangerous security
          issues, and read the *note Extraction filters: 46f. section
          for details.

     Changed in version 3.5: Added the 'numeric_owner' parameter.

     Changed in version 3.6: The 'path' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.12: Added the 'filter' parameter.

 -- Method: TarFile.extract (member, path='', set_attrs=True, *,
          numeric_owner=False, filter=None)

     Extract a member from the archive to the current working directory,
     using its full name.  Its file information is extracted as
     accurately as possible.  'member' may be a filename or a *note
     TarInfo: 1256. object.  You can specify a different directory using
     'path'.  'path' may be a *note path-like object: 2a0.  File
     attributes (owner, mtime, mode) are set unless 'set_attrs' is
     false.

     The 'numeric_owner' and 'filter' arguments are the same as for
     *note extractall(): 431.

          Note: The ‘extract()’ method does not take care of several
          extraction issues.  In most cases you should consider using
          the *note extractall(): 431. method.

          Warning: See the warning for *note extractall(): 431.

          Set ‘filter='data'’ to prevent the most dangerous security
          issues, and read the *note Extraction filters: 46f. section
          for details.

     Changed in version 3.2: Added the 'set_attrs' parameter.

     Changed in version 3.5: Added the 'numeric_owner' parameter.

     Changed in version 3.6: The 'path' parameter accepts a *note
     path-like object: 2a0.

     Changed in version 3.12: Added the 'filter' parameter.

 -- Method: TarFile.extractfile (member)

     Extract a member from the archive as a file object.  'member' may
     be a filename or a *note TarInfo: 1256. object.  If 'member' is a
     regular file or a link, an *note io.BufferedReader: 1253. object is
     returned.  For all other existing members, *note None: 678. is
     returned.  If 'member' does not appear in the archive, *note
     KeyError: 345. is raised.

     Changed in version 3.3: Return an *note io.BufferedReader: 1253.
     object.

     Changed in version 3.13: The returned *note io.BufferedReader:
     1253. object has the ‘mode’ attribute which is always equal to
     ‘'rb'’.

 -- Attribute: TarFile.errorlevel: *note int: 257.

     If 'errorlevel' is ‘0’, errors are ignored when using *note
     TarFile.extract(): 432. and *note TarFile.extractall(): 431.
     Nevertheless, they appear as error messages in the debug output
     when 'debug' is greater than 0.  If ‘1’ (the default), all 'fatal'
     errors are raised as *note OSError: 41a. or *note FilterError:
     2be5. exceptions.  If ‘2’, all 'non-fatal' errors are raised as
     *note TarError: 2be0. exceptions as well.

     Some exceptions, e.g.  ones caused by wrong argument types or data
     corruption, are always raised.

     Custom *note extraction filters: 46f. should raise *note
     FilterError: 2be5. for 'fatal' errors and *note ExtractError: 2be2.
     for 'non-fatal' ones.

     Note that when an exception is raised, the archive may be partially
     extracted.  It is the user’s responsibility to clean up.

 -- Attribute: TarFile.extraction_filter

     Added in version 3.12.

     The *note extraction filter: 46f. used as a default for the
     'filter' argument of *note extract(): 432. and *note extractall():
     431.

     The attribute may be ‘None’ or a callable.  String names are not
     allowed for this attribute, unlike the 'filter' argument to *note
     extract(): 432.

     If ‘extraction_filter’ is ‘None’ (the default), calling an
     extraction method without a 'filter' argument will raise a
     ‘DeprecationWarning’, and fall back to the *note fully_trusted:
     2c07. filter, whose dangerous behavior matches previous versions of
     Python.

     In Python 3.14+, leaving ‘extraction_filter=None’ will cause
     extraction methods to use the *note data: 430. filter by default.

     The attribute may be set on instances or overridden in subclasses.
     It also is possible to set it on the ‘TarFile’ class itself to set
     a global default, although, since it affects all uses of 'tarfile',
     it is best practice to only do so in top-level applications or
     *note site configuration: c7.  To set a global default this way, a
     filter function needs to be wrapped in *note staticmethod(): 419.
     to prevent injection of a ‘self’ argument.

 -- Method: TarFile.add (name, arcname=None, recursive=True, *,
          filter=None)

     Add the file 'name' to the archive.  'name' may be any type of file
     (directory, fifo, symbolic link, etc.).  If given, 'arcname'
     specifies an alternative name for the file in the archive.
     Directories are added recursively by default.  This can be avoided
     by setting 'recursive' to *note False: b4f.  Recursion adds entries
     in sorted order.  If 'filter' is given, it should be a function
     that takes a *note TarInfo: 1256. object argument and returns the
     changed ‘TarInfo’ object.  If it instead returns *note None: 678.
     the ‘TarInfo’ object will be excluded from the archive.  See *note
     Examples: 2bdf. for an example.

     Changed in version 3.2: Added the 'filter' parameter.

     Changed in version 3.7: Recursion adds entries in sorted order.

 -- Method: TarFile.addfile (tarinfo, fileobj=None)

     Add the *note TarInfo: 1256. object 'tarinfo' to the archive.  If
     'tarinfo' represents a non zero-size regular file, the 'fileobj'
     argument should be a *note binary file: 1e26, and ‘tarinfo.size’
     bytes are read from it and added to the archive.  You can create
     ‘TarInfo’ objects directly, or by using *note gettarinfo(): 2c08.

     Changed in version 3.13: 'fileobj' must be given for non-zero-sized
     regular files.

 -- Method: TarFile.gettarinfo (name=None, arcname=None, fileobj=None)

     Create a *note TarInfo: 1256. object from the result of *note
     os.stat(): 4a3. or equivalent on an existing file.  The file is
     either named by 'name', or specified as a *note file object: 1208.
     'fileobj' with a file descriptor.  'name' may be a *note path-like
     object: 2a0.  If given, 'arcname' specifies an alternative name for
     the file in the archive, otherwise, the name is taken from
     'fileobj'’s *note name: 2b6f. attribute, or the 'name' argument.
     The name should be a text string.

     You can modify some of the *note TarInfo: 1256.’s attributes before
     you add it using *note addfile(): 1739.  If the file object is not
     an ordinary file object positioned at the beginning of the file,
     attributes such as *note size: 2c09. may need modifying.  This is
     the case for objects such as *note GzipFile: 41d.  The *note name:
     2c0a. may also be modified, in which case 'arcname' could be a
     dummy string.

     Changed in version 3.6: The 'name' parameter accepts a *note
     path-like object: 2a0.

 -- Method: TarFile.close ()

     Close the *note TarFile: 1255.  In write mode, two finishing zero
     blocks are appended to the archive.

 -- Attribute: TarFile.pax_headers: *note dict: 256.

     A dictionary containing key-value pairs of pax global headers.


File: python.info,  Node: TarInfo Objects,  Next: Extraction filters,  Prev: TarFile Objects,  Up: tarfile — Read and write tar archive files

5.13.6.2 TarInfo Objects
........................

A *note TarInfo: 1256. object represents one member in a *note TarFile:
1255.  Aside from storing all required attributes of a file (like file
type, size, time, permissions, owner etc.), it provides some useful
methods to determine its type.  It does 'not' contain the file’s data
itself.

*note TarInfo: 1256. objects are returned by *note TarFile: 1255.’s
methods *note getmember(): 1994, *note getmembers(): ead. and *note
gettarinfo(): 2c08.

Modifying the objects returned by *note getmember(): 1994. or *note
getmembers(): ead. will affect all subsequent operations on the archive.
For cases where this is unwanted, you can use *note copy.copy(): 25. or
call the *note replace(): 2c0e. method to create a modified copy in one
step.

Several attributes can be set to ‘None’ to indicate that a piece of
metadata is unused or unknown.  Different *note TarInfo: 1256. methods
handle ‘None’ differently:

   - The *note extract(): 432. or *note extractall(): 431. methods will
     ignore the corresponding metadata, leaving it set to a default.

   - *note addfile(): 1739. will fail.

   - *note list(): eac. will print a placeholder string.

 -- Class: tarfile.TarInfo (name='')

     Create a ‘TarInfo’ object.

 -- Method: classmethod TarInfo.frombuf (buf, encoding, errors)

     Create and return a *note TarInfo: 1256. object from string buffer
     'buf'.

     Raises *note HeaderError: 2be3. if the buffer is invalid.

 -- Method: classmethod TarInfo.fromtarfile (tarfile)

     Read the next member from the *note TarFile: 1255. object 'tarfile'
     and return it as a *note TarInfo: 1256. object.

 -- Method: TarInfo.tobuf (format=DEFAULT_FORMAT, encoding=ENCODING,
          errors='surrogateescape')

     Create a string buffer from a *note TarInfo: 1256. object.  For
     information on the arguments see the constructor of the *note
     TarFile: 1255. class.

     Changed in version 3.2: Use ‘'surrogateescape'’ as the default for
     the 'errors' argument.

A ‘TarInfo’ object has the following public data attributes:

 -- Attribute: TarInfo.name: *note str: 44f.

     Name of the archive member.

 -- Attribute: TarInfo.size: *note int: 257.

     Size in bytes.

 -- Attribute: TarInfo.mtime: *note int: 257. | *note float: 2f7.

     Time of last modification in seconds since the *note epoch: 2c12,
     as in *note os.stat_result.st_mtime: 2c13.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.mode: *note int: 257.

     Permission bits, as for *note os.chmod(): 21b.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.type

     File type.  'type' is usually one of these constants: *note
     REGTYPE: 2bef, *note AREGTYPE: 2bf0, *note LNKTYPE: 2bf2, *note
     SYMTYPE: 2bf3, *note DIRTYPE: 2bf6, *note FIFOTYPE: 2bf7, *note
     CONTTYPE: 2bf8, *note CHRTYPE: 2bf4, *note BLKTYPE: 2bf5, *note
     GNUTYPE_SPARSE: 2bfb.  To determine the type of a *note TarInfo:
     1256. object more conveniently, use the ‘is*()’ methods below.

 -- Attribute: TarInfo.linkname: *note str: 44f.

     Name of the target file name, which is only present in *note
     TarInfo: 1256. objects of type *note LNKTYPE: 2bf2. and *note
     SYMTYPE: 2bf3.

     For symbolic links (‘SYMTYPE’), the 'linkname' is relative to the
     directory that contains the link.  For hard links (‘LNKTYPE’), the
     'linkname' is relative to the root of the archive.

 -- Attribute: TarInfo.uid: *note int: 257.

     User ID of the user who originally stored this member.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.gid: *note int: 257.

     Group ID of the user who originally stored this member.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.uname: *note str: 44f.

     User name.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.gname: *note str: 44f.

     Group name.

     Changed in version 3.12: Can be set to ‘None’ for *note extract():
     432. and *note extractall(): 431, causing extraction to skip
     applying this attribute.

 -- Attribute: TarInfo.chksum: *note int: 257.

     Header checksum.

 -- Attribute: TarInfo.devmajor: *note int: 257.

     Device major number.

 -- Attribute: TarInfo.devminor: *note int: 257.

     Device minor number.

 -- Attribute: TarInfo.offset: *note int: 257.

     The tar header starts here.

 -- Attribute: TarInfo.offset_data: *note int: 257.

     The file’s data starts here.

 -- Attribute: TarInfo.sparse

     Sparse member information.

 -- Attribute: TarInfo.pax_headers: *note dict: 256.

     A dictionary containing key-value pairs of an associated pax
     extended header.

 -- Method: TarInfo.replace (name=..., mtime=..., mode=...,
          linkname=..., uid=..., gid=..., uname=..., gname=...,
          deep=True)

     Added in version 3.12.

     Return a 'new' copy of the ‘TarInfo’ object with the given
     attributes changed.  For example, to return a ‘TarInfo’ with the
     group name set to ‘'staff'’, use:

          new_tarinfo = old_tarinfo.replace(gname='staff')

     By default, a deep copy is made.  If 'deep' is false, the copy is
     shallow, i.e.  ‘pax_headers’ and any custom attributes are shared
     with the original ‘TarInfo’ object.

A *note TarInfo: 1256. object also provides some convenient query
methods:

 -- Method: TarInfo.isfile ()

     Return *note True: c2d. if the *note TarInfo: 1256. object is a
     regular file.

 -- Method: TarInfo.isreg ()

     Same as *note isfile(): 2c21.

 -- Method: TarInfo.isdir ()

     Return *note True: c2d. if it is a directory.

 -- Method: TarInfo.issym ()

     Return *note True: c2d. if it is a symbolic link.

 -- Method: TarInfo.islnk ()

     Return *note True: c2d. if it is a hard link.

 -- Method: TarInfo.ischr ()

     Return *note True: c2d. if it is a character device.

 -- Method: TarInfo.isblk ()

     Return *note True: c2d. if it is a block device.

 -- Method: TarInfo.isfifo ()

     Return *note True: c2d. if it is a FIFO.

 -- Method: TarInfo.isdev ()

     Return *note True: c2d. if it is one of character device, block
     device or FIFO.


File: python.info,  Node: Extraction filters,  Next: Command-Line Interface,  Prev: TarInfo Objects,  Up: tarfile — Read and write tar archive files

5.13.6.3 Extraction filters
...........................

Added in version 3.12.

The 'tar' format is designed to capture all details of a UNIX-like
filesystem, which makes it very powerful.  Unfortunately, the features
make it easy to create tar files that have unintended – and possibly
malicious – effects when extracted.  For example, extracting a tar file
can overwrite arbitrary files in various ways (e.g.  by using absolute
paths, ‘..’ path components, or symlinks that affect later members).

In most cases, the full functionality is not needed.  Therefore,
'tarfile' supports extraction filters: a mechanism to limit
functionality, and thus mitigate some of the security issues.

See also
........

PEP 706(1)

     Contains further motivation and rationale behind the design.

The 'filter' argument to *note TarFile.extract(): 432. or *note
extractall(): 431. can be:

   * the string ‘'fully_trusted'’: Honor all metadata as specified in
     the archive.  Should be used if the user trusts the archive
     completely, or implements their own complex verification.

   * the string ‘'tar'’: Honor most 'tar'-specific features (i.e.
     features of UNIX-like filesystems), but block features that are
     very likely to be surprising or malicious.  See *note tar_filter():
     2c2b. for details.

   * the string ‘'data'’: Ignore or block most features specific to
     UNIX-like filesystems.  Intended for extracting cross-platform data
     archives.  See *note data_filter(): 430. for details.

   * ‘None’ (default): Use *note TarFile.extraction_filter: 2c06.

     If that is also ‘None’ (the default), raise a ‘DeprecationWarning’,
     and fall back to the ‘'fully_trusted'’ filter, whose dangerous
     behavior matches previous versions of Python.

     In Python 3.14, the ‘'data'’ filter will become the default
     instead.  It’s possible to switch earlier; see *note
     TarFile.extraction_filter: 2c06.

   * A callable which will be called for each extracted member with a
     *note TarInfo: 2be8. describing the member and the destination path
     to where the archive is extracted (i.e.  the same path is used for
     all members):

          filter(member: TarInfo, path: str, /) -> TarInfo | None

     The callable is called just before each member is extracted, so it
     can take the current state of the disk into account.  It can:

        - return a *note TarInfo: 1256. object which will be used
          instead of the metadata in the archive, or

        - return ‘None’, in which case the member will be skipped, or

        - raise an exception to abort the operation or skip the member,
          depending on *note errorlevel: 434.  Note that when extraction
          is aborted, *note extractall(): 431. may leave the archive
          partially extracted.  It does not attempt to clean up.

* Menu:

* Default named filters::
* Filter errors::
* Hints for further verification::
* Supporting older Python versions::
* Stateful extraction filter example::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0706/


File: python.info,  Node: Default named filters,  Next: Filter errors,  Up: Extraction filters

5.13.6.4 Default named filters
..............................

The pre-defined, named filters are available as functions, so they can
be reused in custom filters:

 -- Function: tarfile.fully_trusted_filter (member, path)

     Return 'member' unchanged.

     This implements the ‘'fully_trusted'’ filter.

 -- Function: tarfile.tar_filter (member, path)

     Implements the ‘'tar'’ filter.

        - Strip leading slashes (‘/’ and *note os.sep: 66d.) from
          filenames.

        - *note Refuse: 2be6. to extract files with absolute paths (in
          case the name is absolute even after stripping slashes, e.g.
          ‘C:/foo’ on Windows).  This raises *note AbsolutePathError:
          2be9.

        - *note Refuse: 2be6. to extract files whose absolute path
          (after following symlinks) would end up outside the
          destination.  This raises *note OutsideDestinationError: 2bea.

        - Clear high mode bits (setuid, setgid, sticky) and group/other
          write bits (*note S_IWGRP: 29d5. | *note S_IWOTH: 29d8.).

     Return the modified ‘TarInfo’ member.

 -- Function: tarfile.data_filter (member, path)

     Implements the ‘'data'’ filter.  In addition to what ‘tar_filter’
     does:

        - Normalize link targets (*note TarInfo.linkname: 2c15.) using
          *note os.path.normpath(): 1363.  Note that this removes
          internal ‘..’ components, which may change the meaning of the
          link if the path in ‘TarInfo.linkname’ traverses symbolic
          links.

        - *note Refuse: 2be6. to extract links (hard or soft) that link
          to absolute paths, or ones that link outside the destination.

          This raises *note AbsoluteLinkError: 2bec. or *note
          LinkOutsideDestinationError: 2bed.

          Note that such files are refused even on platforms that do not
          support symbolic links.

        - *note Refuse: 2be6. to extract device files (including pipes).
          This raises *note SpecialFileError: 2beb.

        - For regular files, including hard links:

             - Set the owner read and write permissions (*note S_IRUSR:
               29d0. | *note S_IWUSR: 29d1.).

             - Remove the group & other executable permission (*note
               S_IXGRP: 29cc. | *note S_IXOTH: 29d9.) if the owner
               doesn’t have it (*note S_IXUSR: 29d2.).

        - For other files (directories), set ‘mode’ to ‘None’, so that
          extraction methods skip applying permission bits.

        - Set user and group info (‘uid’, ‘gid’, ‘uname’, ‘gname’) to
          ‘None’, so that extraction methods skip setting it.

     Return the modified ‘TarInfo’ member.

     Changed in version 3.13.4: Link targets are now normalized.


File: python.info,  Node: Filter errors,  Next: Hints for further verification,  Prev: Default named filters,  Up: Extraction filters

5.13.6.5 Filter errors
......................

When a filter refuses to extract a file, it will raise an appropriate
exception, a subclass of *note FilterError: 2be5.  This will abort the
extraction if *note TarFile.errorlevel: 434. is 1 or more.  With
‘errorlevel=0’ the error will be logged and the member will be skipped,
but extraction will continue.


File: python.info,  Node: Hints for further verification,  Next: Supporting older Python versions,  Prev: Filter errors,  Up: Extraction filters

5.13.6.6 Hints for further verification
.......................................

Even with ‘filter='data'’, 'tarfile' is not suited for extracting
untrusted files without prior inspection.  Among other issues, the
pre-defined filters do not prevent denial-of-service attacks.  Users
should do additional checks.

Here is an incomplete list of things to consider:

   * Extract to a *note new temporary directory: 21f. to prevent e.g.
     exploiting pre-existing links, and to make it easier to clean up
     after a failed extraction.

   * Disallow symbolic links if you do not need the functionality.

   * When working with untrusted data, use external (e.g.  OS-level)
     limits on disk, memory and CPU usage.

   * Check filenames against an allow-list of characters (to filter out
     control characters, confusables, foreign path separators, etc.).

   * Check that filenames have expected extensions (discouraging files
     that execute when you “click on them”, or extension-less files like
     Windows special device names).

   * Limit the number of extracted files, total size of extracted data,
     filename length (including symlink length), and size of individual
     files.

   * Check for files that would be shadowed on case-insensitive
     filesystems.

Also note that:

   * Tar files may contain multiple versions of the same file.  Later
     ones are expected to overwrite any earlier ones.  This feature is
     crucial to allow updating tape archives, but can be abused
     maliciously.

   * 'tarfile' does not protect against issues with “live” data, e.g.
     an attacker tinkering with the destination (or source) directory
     while extraction (or archiving) is in progress.


File: python.info,  Node: Supporting older Python versions,  Next: Stateful extraction filter example,  Prev: Hints for further verification,  Up: Extraction filters

5.13.6.7 Supporting older Python versions
.........................................

Extraction filters were added to Python 3.12, but may be backported to
older versions as security updates.  To check whether the feature is
available, use e.g.  ‘hasattr(tarfile, 'data_filter')’ rather than
checking the Python version.

The following examples show how to support Python versions with and
without the feature.  Note that setting ‘extraction_filter’ will affect
any subsequent operations.

   * Fully trusted archive:

          my_tarfile.extraction_filter = (lambda member, path: member)
          my_tarfile.extractall()

   * Use the ‘'data'’ filter if available, but revert to Python 3.11
     behavior (‘'fully_trusted'’) if this feature is not available:

          my_tarfile.extraction_filter = getattr(tarfile, 'data_filter',
                                                 (lambda member, path: member))
          my_tarfile.extractall()

   * Use the ‘'data'’ filter; 'fail' if it is not available:

          my_tarfile.extractall(filter=tarfile.data_filter)

     or:

          my_tarfile.extraction_filter = tarfile.data_filter
          my_tarfile.extractall()

   * Use the ‘'data'’ filter; 'warn' if it is not available:

          if hasattr(tarfile, 'data_filter'):
              my_tarfile.extractall(filter='data')
          else:
              # remove this when no longer needed
              warn_the_user('Extracting may be unsafe; consider updating Python')
              my_tarfile.extractall()


File: python.info,  Node: Stateful extraction filter example,  Prev: Supporting older Python versions,  Up: Extraction filters

5.13.6.8 Stateful extraction filter example
...........................................

While 'tarfile'’s extraction methods take a simple 'filter' callable,
custom filters may be more complex objects with an internal state.  It
may be useful to write these as context managers, to be used like this:

     with StatefulFilter() as filter_func:
         tar.extractall(path, filter=filter_func)

Such a filter can be written as, for example:

     class StatefulFilter:
         def __init__(self):
             self.file_count = 0

         def __enter__(self):
             return self

         def __call__(self, member, path):
             self.file_count += 1
             return member

         def __exit__(self, *exc_info):
             print(f'{self.file_count} files extracted')


File: python.info,  Node: Command-Line Interface,  Next: Examples<9>,  Prev: Extraction filters,  Up: tarfile — Read and write tar archive files

5.13.6.9 Command-Line Interface
...............................

Added in version 3.4.

The ‘tarfile’ module provides a simple command-line interface to
interact with tar archives.

If you want to create a new tar archive, specify its name after the
*note -c: 2c32. option and then list the filename(s) that should be
included:

     $ python -m tarfile -c monty.tar  spam.txt eggs.txt

Passing a directory is also acceptable:

     $ python -m tarfile -c monty.tar life-of-brian_1979/

If you want to extract a tar archive into the current directory, use the
*note -e: 2c33. option:

     $ python -m tarfile -e monty.tar

You can also extract a tar archive into a different directory by passing
the directory’s name:

     $ python -m tarfile -e monty.tar  other-dir/

For a list of the files in a tar archive, use the *note -l: 2c34.
option:

     $ python -m tarfile -l monty.tar

* Menu:

* Command-line options: Command-line options<3>.


File: python.info,  Node: Command-line options<3>,  Up: Command-Line Interface

5.13.6.10 Command-line options
..............................

 -- Option: -l <tarfile>
 -- Option: --list <tarfile>

     List files in a tarfile.

 -- Option: -c <tarfile> <source1> ... <sourceN>
 -- Option: --create <tarfile> <source1> ... <sourceN>

     Create tarfile from source files.

 -- Option: -e <tarfile> [<output_dir>]
 -- Option: --extract <tarfile> [<output_dir>]

     Extract tarfile into the current directory if 'output_dir' is not
     specified.

 -- Option: -t <tarfile>
 -- Option: --test <tarfile>

     Test whether the tarfile is valid or not.

 -- Option: -v, --verbose

     Verbose output.

 -- Option: --filter <filtername>

     Specifies the 'filter' for ‘--extract’.  See *note Extraction
     filters: 46f. for details.  Only string names are accepted (that
     is, ‘fully_trusted’, ‘tar’, and ‘data’).


File: python.info,  Node: Examples<9>,  Next: Supported tar formats,  Prev: Command-Line Interface,  Up: tarfile — Read and write tar archive files

5.13.6.11 Examples
..................

* Menu:

* Reading examples::
* Writing examples::


File: python.info,  Node: Reading examples,  Next: Writing examples,  Up: Examples<9>

5.13.6.12 Reading examples
..........................

How to extract an entire tar archive to the current working directory:

     import tarfile
     tar = tarfile.open("sample.tar.gz")
     tar.extractall(filter='data')
     tar.close()

How to extract a subset of a tar archive with *note
TarFile.extractall(): 431. using a generator function instead of a list:

     import os
     import tarfile

     def py_files(members):
         for tarinfo in members:
             if os.path.splitext(tarinfo.name)[1] == ".py":
                 yield tarinfo

     tar = tarfile.open("sample.tar.gz")
     tar.extractall(members=py_files(tar))
     tar.close()

How to read a gzip compressed tar archive and display some member
information:

     import tarfile
     tar = tarfile.open("sample.tar.gz", "r:gz")
     for tarinfo in tar:
         print(tarinfo.name, "is", tarinfo.size, "bytes in size and is ", end="")
         if tarinfo.isreg():
             print("a regular file.")
         elif tarinfo.isdir():
             print("a directory.")
         else:
             print("something else.")
     tar.close()


File: python.info,  Node: Writing examples,  Prev: Reading examples,  Up: Examples<9>

5.13.6.13 Writing examples
..........................

How to create an uncompressed tar archive from a list of filenames:

     import tarfile
     tar = tarfile.open("sample.tar", "w")
     for name in ["foo", "bar", "quux"]:
         tar.add(name)
     tar.close()

The same example using the *note with: 5d5. statement:

     import tarfile
     with tarfile.open("sample.tar", "w") as tar:
         for name in ["foo", "bar", "quux"]:
             tar.add(name)

How to create and write an archive to stdout using *note
sys.stdout.buffer: aec. in the 'fileobj' parameter in *note
TarFile.add(): c14.:

     import sys
     import tarfile
     with tarfile.open("sample.tar.gz", "w|gz", fileobj=sys.stdout.buffer) as tar:
         for name in ["foo", "bar", "quux"]:
             tar.add(name)

How to create an archive and reset the user information using the
'filter' parameter in *note TarFile.add(): c14.:

     import tarfile
     def reset(tarinfo):
         tarinfo.uid = tarinfo.gid = 0
         tarinfo.uname = tarinfo.gname = "root"
         return tarinfo
     tar = tarfile.open("sample.tar.gz", "w:gz")
     tar.add("foo", filter=reset)
     tar.close()


File: python.info,  Node: Supported tar formats,  Next: Unicode issues,  Prev: Examples<9>,  Up: tarfile — Read and write tar archive files

5.13.6.14 Supported tar formats
...............................

There are three tar formats that can be created with the ‘tarfile’
module:

   * The POSIX.1-1988 ustar format (*note USTAR_FORMAT: 2bfd.).  It
     supports filenames up to a length of at best 256 characters and
     linknames up to 100 characters.  The maximum file size is 8 GiB.
     This is an old and limited but widely supported format.

   * The GNU tar format (*note GNU_FORMAT: 2bfe.).  It supports long
     filenames and linknames, files bigger than 8 GiB and sparse files.
     It is the de facto standard on GNU/Linux systems.  ‘tarfile’ fully
     supports the GNU tar extensions for long names, sparse file support
     is read-only.

   * The POSIX.1-2001 pax format (*note PAX_FORMAT: 2bff.).  It is the
     most flexible format with virtually no limits.  It supports long
     filenames and linknames, large files and stores pathnames in a
     portable way.  Modern tar implementations, including GNU tar,
     bsdtar/libarchive and star, fully support extended 'pax' features;
     some old or unmaintained libraries may not, but should treat 'pax'
     archives as if they were in the universally supported 'ustar'
     format.  It is the current default format for new archives.

     It extends the existing 'ustar' format with extra headers for
     information that cannot be stored otherwise.  There are two
     flavours of pax headers: Extended headers only affect the
     subsequent file header, global headers are valid for the complete
     archive and affect all following files.  All the data in a pax
     header is encoded in 'UTF-8' for portability reasons.

There are some more variants of the tar format which can be read, but
not created:

   * The ancient V7 format.  This is the first tar format from Unix
     Seventh Edition, storing only regular files and directories.  Names
     must not be longer than 100 characters, there is no user/group name
     information.  Some archives have miscalculated header checksums in
     case of fields with non-ASCII characters.

   * The SunOS tar extended format.  This format is a variant of the
     POSIX.1-2001 pax format, but is not compatible.


File: python.info,  Node: Unicode issues,  Prev: Supported tar formats,  Up: tarfile — Read and write tar archive files

5.13.6.15 Unicode issues
........................

The tar format was originally conceived to make backups on tape drives
with the main focus on preserving file system information.  Nowadays tar
archives are commonly used for file distribution and exchanging archives
over networks.  One problem of the original format (which is the basis
of all other formats) is that there is no concept of supporting
different character encodings.  For example, an ordinary tar archive
created on a 'UTF-8' system cannot be read correctly on a 'Latin-1'
system if it contains non-'ASCII' characters.  Textual metadata (like
filenames, linknames, user/group names) will appear damaged.
Unfortunately, there is no way to autodetect the encoding of an archive.
The pax format was designed to solve this problem.  It stores non-ASCII
metadata using the universal character encoding 'UTF-8'.

The details of character conversion in ‘tarfile’ are controlled by the
'encoding' and 'errors' keyword arguments of the *note TarFile: 1255.
class.

'encoding' defines the character encoding to use for the metadata in the
archive.  The default value is *note sys.getfilesystemencoding(): c7a.
or ‘'ascii'’ as a fallback.  Depending on whether the archive is read or
written, the metadata must be either decoded or encoded.  If 'encoding'
is not set appropriately, this conversion may fail.

The 'errors' argument defines how characters are treated that cannot be
converted.  Possible values are listed in section *note Error Handlers:
1915.  The default scheme is ‘'surrogateescape'’ which Python also uses
for its file system calls, see *note File Names, Command Line Arguments,
and Environment Variables: 2c43.

For *note PAX_FORMAT: 2bff. archives (the default), 'encoding' is
generally not needed because all the metadata is stored using 'UTF-8'.
'encoding' is only used in the rare cases when binary pax headers are
decoded or when strings with surrogate characters are stored.


File: python.info,  Node: File Formats,  Next: Cryptographic Services,  Prev: Data Compression and Archiving,  Up: The Python Standard Library

5.14 File Formats
=================

The modules described in this chapter parse various miscellaneous file
formats that aren’t markup languages and are not related to e-mail.

* Menu:

* csv — CSV File Reading and Writing::
* configparser — Configuration file parser::
* tomllib — Parse TOML files::
* netrc — netrc file processing::
* plistlib — Generate and parse Apple .plist files: plistlib — Generate and parse Apple plist files.


File: python.info,  Node: csv — CSV File Reading and Writing,  Next: configparser — Configuration file parser,  Up: File Formats

5.14.1 ‘csv’ — CSV File Reading and Writing
-------------------------------------------

'Source code:' Lib/csv.py(1)

__________________________________________________________________

The so-called CSV (Comma Separated Values) format is the most common
import and export format for spreadsheets and databases.  CSV format was
used for many years prior to attempts to describe the format in a
standardized way in RFC 4180(2).  The lack of a well-defined standard
means that subtle differences often exist in the data produced and
consumed by different applications.  These differences can make it
annoying to process CSV files from multiple sources.  Still, while the
delimiters and quoting characters vary, the overall format is similar
enough that it is possible to write a single module which can
efficiently manipulate such data, hiding the details of reading and
writing the data from the programmer.

The ‘csv’ module implements classes to read and write tabular data in
CSV format.  It allows programmers to say, “write this data in the
format preferred by Excel,” or “read data from this file which was
generated by Excel,” without knowing the precise details of the CSV
format used by Excel.  Programmers can also describe the CSV formats
understood by other applications or define their own special-purpose CSV
formats.

The ‘csv’ module’s *note reader: 489. and *note writer: 48a. objects
read and write sequences.  Programmers can also read and write data in
dictionary form using the *note DictReader: 9f0. and *note DictWriter:
1243. classes.

See also
........

PEP 305(3) - CSV File API

     The Python Enhancement Proposal which proposed this addition to
     Python.

* Menu:

* Module Contents: Module Contents<2>.
* Dialects and Formatting Parameters::
* Reader Objects::
* Writer Objects::
* Examples: Examples<10>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/csv.py

   (2) https://datatracker.ietf.org/doc/html/rfc4180.html

   (3) https://peps.python.org/pep-0305/


File: python.info,  Node: Module Contents<2>,  Next: Dialects and Formatting Parameters,  Up: csv — CSV File Reading and Writing

5.14.1.1 Module Contents
........................

The ‘csv’ module defines the following functions:

 -- Function: csv.reader (csvfile, /, dialect='excel', **fmtparams)

     Return a *note reader object: 2c4c. that will process lines from
     the given 'csvfile'.  A csvfile must be an iterable of strings,
     each in the reader’s defined csv format.  A csvfile is most
     commonly a file-like object or list.  If 'csvfile' is a file
     object, it should be opened with ‘newline=''’.  (1)  An optional
     'dialect' parameter can be given which is used to define a set of
     parameters specific to a particular CSV dialect.  It may be an
     instance of a subclass of the *note Dialect: 178e. class or one of
     the strings returned by the *note list_dialects(): 193a. function.
     The other optional 'fmtparams' keyword arguments can be given to
     override individual formatting parameters in the current dialect.
     For full details about the dialect and formatting parameters, see
     section *note Dialects and Formatting Parameters: 2c4d.

     Each row read from the csv file is returned as a list of strings.
     No automatic data type conversion is performed unless the *note
     QUOTE_NONNUMERIC: 16f5. format option is specified (in which case
     unquoted fields are transformed into floats).

     A short usage example:

          >>> import csv
          >>> with open('eggs.csv', newline='') as csvfile:
          ...     spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
          ...     for row in spamreader:
          ...         print(', '.join(row))
          Spam, Spam, Spam, Spam, Spam, Baked Beans
          Spam, Lovely Spam, Wonderful Spam

 -- Function: csv.writer (csvfile, /, dialect='excel', **fmtparams)

     Return a writer object responsible for converting the user’s data
     into delimited strings on the given file-like object.  'csvfile'
     can be any object with a *note write(): 1e13. method.  If 'csvfile'
     is a file object, it should be opened with ‘newline=''’ (2).  An
     optional 'dialect' parameter can be given which is used to define a
     set of parameters specific to a particular CSV dialect.  It may be
     an instance of a subclass of the *note Dialect: 178e. class or one
     of the strings returned by the *note list_dialects(): 193a.
     function.  The other optional 'fmtparams' keyword arguments can be
     given to override individual formatting parameters in the current
     dialect.  For full details about dialects and formatting
     parameters, see the *note Dialects and Formatting Parameters: 2c4d.
     section.  To make it as easy as possible to interface with modules
     which implement the DB API, the value *note None: 678. is written
     as the empty string.  While this isn’t a reversible transformation,
     it makes it easier to dump SQL NULL data values to CSV files
     without preprocessing the data returned from a ‘cursor.fetch*’
     call.  All other non-string data are stringified with *note str():
     44f. before being written.

     A short usage example:

          import csv
          with open('eggs.csv', 'w', newline='') as csvfile:
              spamwriter = csv.writer(csvfile, delimiter=' ',
                                      quotechar='|', quoting=csv.QUOTE_MINIMAL)
              spamwriter.writerow(['Spam'] * 5 + ['Baked Beans'])
              spamwriter.writerow(['Spam', 'Lovely Spam', 'Wonderful Spam'])

 -- Function: csv.register_dialect (name, /, dialect='excel',
          **fmtparams)

     Associate 'dialect' with 'name'.  'name' must be a string.  The
     dialect can be specified either by passing a sub-class of *note
     Dialect: 178e, or by 'fmtparams' keyword arguments, or both, with
     keyword arguments overriding parameters of the dialect.  For full
     details about dialects and formatting parameters, see section *note
     Dialects and Formatting Parameters: 2c4d.

 -- Function: csv.unregister_dialect (name)

     Delete the dialect associated with 'name' from the dialect
     registry.  An *note Error: 2c4f. is raised if 'name' is not a
     registered dialect name.

 -- Function: csv.get_dialect (name)

     Return the dialect associated with 'name'.  An *note Error: 2c4f.
     is raised if 'name' is not a registered dialect name.  This
     function returns an immutable *note Dialect: 178e.

 -- Function: csv.list_dialects ()

     Return the names of all registered dialects.

 -- Function: csv.field_size_limit ()

 -- Function: csv.field_size_limit (new_limit)

     Returns the current maximum field size allowed by the parser.  If
     'new_limit' is given, this becomes the new limit.

The ‘csv’ module defines the following classes:

 -- Class: csv.DictReader (f, fieldnames=None, restkey=None,
          restval=None, dialect='excel', *args, **kwds)

     Create an object that operates like a regular reader but maps the
     information in each row to a *note dict: 256. whose keys are given
     by the optional 'fieldnames' parameter.

     The 'fieldnames' parameter is a *note sequence: 4f4.  If
     'fieldnames' is omitted, the values in the first row of file 'f'
     will be used as the fieldnames and will be omitted from the
     results.  If 'fieldnames' is provided, they will be used and the
     first row will be included in the results.  Regardless of how the
     fieldnames are determined, the dictionary preserves their original
     ordering.

     If a row has more fields than fieldnames, the remaining data is put
     in a list and stored with the fieldname specified by 'restkey'
     (which defaults to ‘None’).  If a non-blank row has fewer fields
     than fieldnames, the missing values are filled-in with the value of
     'restval' (which defaults to ‘None’).

     All other optional or keyword arguments are passed to the
     underlying *note reader: 489. instance.

     If the argument passed to 'fieldnames' is an iterator, it will be
     coerced to a *note list: 614.

     Changed in version 3.6: Returned rows are now of type
     ‘OrderedDict’.

     Changed in version 3.8: Returned rows are now of type *note dict:
     256.

     A short usage example:

          >>> import csv
          >>> with open('names.csv', newline='') as csvfile:
          ...     reader = csv.DictReader(csvfile)
          ...     for row in reader:
          ...         print(row['first_name'], row['last_name'])
          ...
          Eric Idle
          John Cleese

          >>> print(row)
          {'first_name': 'John', 'last_name': 'Cleese'}

 -- Class: csv.DictWriter (f, fieldnames, restval='',
          extrasaction='raise', dialect='excel', *args, **kwds)

     Create an object which operates like a regular writer but maps
     dictionaries onto output rows.  The 'fieldnames' parameter is a
     *note sequence: 1e. of keys that identify the order in which values
     in the dictionary passed to the *note writerow(): e1a. method are
     written to file 'f'.  The optional 'restval' parameter specifies
     the value to be written if the dictionary is missing a key in
     'fieldnames'.  If the dictionary passed to the ‘writerow()’ method
     contains a key not found in 'fieldnames', the optional
     'extrasaction' parameter indicates what action to take.  If it is
     set to ‘'raise'’, the default value, a *note ValueError: 202. is
     raised.  If it is set to ‘'ignore'’, extra values in the dictionary
     are ignored.  Any other optional or keyword arguments are passed to
     the underlying *note writer: 48a. instance.

     Note that unlike the *note DictReader: 9f0. class, the 'fieldnames'
     parameter of the ‘DictWriter’ class is not optional.

     If the argument passed to 'fieldnames' is an iterator, it will be
     coerced to a *note list: 614.

     A short usage example:

          import csv

          with open('names.csv', 'w', newline='') as csvfile:
              fieldnames = ['first_name', 'last_name']
              writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

              writer.writeheader()
              writer.writerow({'first_name': 'Baked', 'last_name': 'Beans'})
              writer.writerow({'first_name': 'Lovely', 'last_name': 'Spam'})
              writer.writerow({'first_name': 'Wonderful', 'last_name': 'Spam'})

 -- Class: csv.Dialect

     The ‘Dialect’ class is a container class whose attributes contain
     information for how to handle doublequotes, whitespace, delimiters,
     etc.  Due to the lack of a strict CSV specification, different
     applications produce subtly different CSV data.  ‘Dialect’
     instances define how *note reader: 489. and *note writer: 48a.
     instances behave.

     All available ‘Dialect’ names are returned by *note
     list_dialects(): 193a, and they can be registered with specific
     *note reader: 489. and *note writer: 48a. classes through their
     initializer (‘__init__’) functions like this:

          import csv

          with open('students.csv', 'w', newline='') as csvfile:
              writer = csv.writer(csvfile, dialect='unix')

 -- Class: csv.excel

     The ‘excel’ class defines the usual properties of an
     Excel-generated CSV file.  It is registered with the dialect name
     ‘'excel'’.

 -- Class: csv.excel_tab

     The ‘excel_tab’ class defines the usual properties of an
     Excel-generated TAB-delimited file.  It is registered with the
     dialect name ‘'excel-tab'’.

 -- Class: csv.unix_dialect

     The ‘unix_dialect’ class defines the usual properties of a CSV file
     generated on UNIX systems, i.e.  using ‘'\n'’ as line terminator
     and quoting all fields.  It is registered with the dialect name
     ‘'unix'’.

     Added in version 3.2.

 -- Class: csv.Sniffer

     The ‘Sniffer’ class is used to deduce the format of a CSV file.

     The ‘Sniffer’ class provides two methods:

      -- Method: sniff (sample, delimiters=None)

          Analyze the given 'sample' and return a *note Dialect: 178e.
          subclass reflecting the parameters found.  If the optional
          'delimiters' parameter is given, it is interpreted as a string
          containing possible valid delimiter characters.

      -- Method: has_header (sample)

          Analyze the sample text (presumed to be in CSV format) and
          return *note True: c2d. if the first row appears to be a
          series of column headers.  Inspecting each column, one of two
          key criteria will be considered to estimate if the sample
          contains a header:

             - the second through n-th rows contain numeric values

             - the second through n-th rows contain strings where at
               least one value’s length differs from that of the
               putative header of that column.

          Twenty-one rows after the header are sampled; if more than
          half of the columns + rows meet the criteria, *note True: c2d.
          is returned.

          Note: This method is a rough heuristic and may produce both
          false positives and negatives.

An example for *note Sniffer: 2c52. use:

     with open('example.csv', newline='') as csvfile:
         dialect = csv.Sniffer().sniff(csvfile.read(1024))
         csvfile.seek(0)
         reader = csv.reader(csvfile, dialect)
         # ... process CSV file contents here ...
The ‘csv’ module defines the following constants:

 -- Data: csv.QUOTE_ALL

     Instructs *note writer: 48a. objects to quote all fields.

 -- Data: csv.QUOTE_MINIMAL

     Instructs *note writer: 48a. objects to only quote those fields
     which contain special characters such as 'delimiter', 'quotechar',
     ‘'\r'’, ‘'\n'’ or any of the characters in 'lineterminator'.

 -- Data: csv.QUOTE_NONNUMERIC

     Instructs *note writer: 48a. objects to quote all non-numeric
     fields.

     Instructs *note reader: 489. objects to convert all non-quoted
     fields to type *note float: 2f7.

          Note: Some numeric types, such as *note bool: 46b, *note
          Fraction: 1e7, or *note IntEnum: d06, have a string
          representation that cannot be converted to *note float: 2f7.
          They cannot be read in the ‘QUOTE_NONNUMERIC’ and *note
          QUOTE_STRINGS: 488. modes.

 -- Data: csv.QUOTE_NONE

     Instructs *note writer: 48a. objects to never quote fields.  When
     the current 'delimiter', 'quotechar', 'escapechar', ‘'\r'’, ‘'\n'’
     or any of the characters in 'lineterminator' occurs in output data
     it is preceded by the current 'escapechar' character.  If
     'escapechar' is not set, the writer will raise *note Error: 2c4f.
     if any characters that require escaping are encountered.  Set
     'quotechar' to ‘None’ to prevent its escaping.

     Instructs *note reader: 489. objects to perform no special
     processing of quote characters.

 -- Data: csv.QUOTE_NOTNULL

     Instructs *note writer: 48a. objects to quote all fields which are
     not ‘None’.  This is similar to *note QUOTE_ALL: 2c55, except that
     if a field value is ‘None’ an empty (unquoted) string is written.

     Instructs *note reader: 489. objects to interpret an empty
     (unquoted) field as ‘None’ and to otherwise behave as *note
     QUOTE_ALL: 2c55.

     Added in version 3.12.

 -- Data: csv.QUOTE_STRINGS

     Instructs *note writer: 48a. objects to always place quotes around
     fields which are strings.  This is similar to *note
     QUOTE_NONNUMERIC: 16f5, except that if a field value is ‘None’ an
     empty (unquoted) string is written.

     Instructs *note reader: 489. objects to interpret an empty
     (unquoted) string as ‘None’ and to otherwise behave as *note
     QUOTE_NONNUMERIC: 16f5.

     Added in version 3.12.

The ‘csv’ module defines the following exception:

 -- Exception: csv.Error

     Raised by any of the functions when an error is detected.

   ---------- Footnotes ----------

   (1) If ‘newline=''’ is not specified, newlines embedded inside quoted
fields will not be interpreted correctly, and on platforms that use
‘\r\n’ line endings on write an extra ‘\r’ will be added.  It should
always be safe to specify ‘newline=''’, since the csv module does its
own (*note universal: d62.) newline handling.

   (2) If ‘newline=''’ is not specified, newlines embedded inside quoted
fields will not be interpreted correctly, and on platforms that use
‘\r\n’ line endings on write an extra ‘\r’ will be added.  It should
always be safe to specify ‘newline=''’, since the csv module does its
own (*note universal: d62.) newline handling.


File: python.info,  Node: Dialects and Formatting Parameters,  Next: Reader Objects,  Prev: Module Contents<2>,  Up: csv — CSV File Reading and Writing

5.14.1.2 Dialects and Formatting Parameters
...........................................

To make it easier to specify the format of input and output records,
specific formatting parameters are grouped together into dialects.  A
dialect is a subclass of the *note Dialect: 178e. class containing
various attributes describing the format of the CSV file.  When creating
*note reader: 489. or *note writer: 48a. objects, the programmer can
specify a string or a subclass of the ‘Dialect’ class as the dialect
parameter.  In addition to, or instead of, the 'dialect' parameter, the
programmer can also specify individual formatting parameters, which have
the same names as the attributes defined below for the ‘Dialect’ class.

Dialects support the following attributes:

 -- Attribute: Dialect.delimiter

     A one-character string used to separate fields.  It defaults to
     ‘','’.

 -- Attribute: Dialect.doublequote

     Controls how instances of 'quotechar' appearing inside a field
     should themselves be quoted.  When *note True: c2d, the character
     is doubled.  When *note False: b4f, the 'escapechar' is used as a
     prefix to the 'quotechar'.  It defaults to ‘True’.

     On output, if 'doublequote' is *note False: b4f. and no
     'escapechar' is set, *note Error: 2c4f. is raised if a 'quotechar'
     is found in a field.

 -- Attribute: Dialect.escapechar

     A one-character string used by the writer to escape characters that
     require escaping:

             * the 'delimiter', the 'quotechar', ‘'\r'’, ‘'\n'’ and any
               of the characters in 'lineterminator' are escaped if
               'quoting' is set to *note QUOTE_NONE: 2c57.;

             * the 'quotechar' is escaped if 'doublequote' is *note
               False: b4f.;

             * the 'escapechar' itself.

     On reading, the 'escapechar' removes any special meaning from the
     following character.  It defaults to *note None: 678, which
     disables escaping.

     Changed in version 3.11: An empty 'escapechar' is not allowed.

 -- Attribute: Dialect.lineterminator

     The string used to terminate lines produced by the *note writer:
     48a.  It defaults to ‘'\r\n'’.

          Note: The *note reader: 489. is hard-coded to recognise either
          ‘'\r'’ or ‘'\n'’ as end-of-line, and ignores 'lineterminator'.
          This behavior may change in the future.

 -- Attribute: Dialect.quotechar

     A one-character string used to quote fields containing special
     characters, such as the 'delimiter' or the 'quotechar', or which
     contain new-line characters (‘'\r'’, ‘'\n'’ or any of the
     characters in 'lineterminator').  It defaults to ‘'"'’.  Can be set
     to ‘None’ to prevent escaping ‘'"'’ if 'quoting' is set to *note
     QUOTE_NONE: 2c57.

     Changed in version 3.11: An empty 'quotechar' is not allowed.

 -- Attribute: Dialect.quoting

     Controls when quotes should be generated by the writer and
     recognised by the reader.  It can take on any of the *note QUOTE_*
     constants: 2c54. and defaults to *note QUOTE_MINIMAL: 2c56. if
     'quotechar' is not ‘None’, and *note QUOTE_NONE: 2c57. otherwise.

 -- Attribute: Dialect.skipinitialspace

     When *note True: c2d, spaces immediately following the 'delimiter'
     are ignored.  The default is *note False: b4f.  When combining
     ‘delimiter=' '’ with ‘skipinitialspace=True’, unquoted empty fields
     are not allowed.

 -- Attribute: Dialect.strict

     When ‘True’, raise exception *note Error: 2c4f. on bad CSV input.
     The default is ‘False’.


File: python.info,  Node: Reader Objects,  Next: Writer Objects,  Prev: Dialects and Formatting Parameters,  Up: csv — CSV File Reading and Writing

5.14.1.3 Reader Objects
.......................

Reader objects (*note DictReader: 9f0. instances and objects returned by
the *note reader(): 489. function) have the following public methods:

 -- Method: csvreader.__next__ ()

     Return the next row of the reader’s iterable object as a list (if
     the object was returned from *note reader(): 489.) or a dict (if it
     is a *note DictReader: 9f0. instance), parsed according to the
     current *note Dialect: 178e.  Usually you should call this as
     ‘next(reader)’.

Reader objects have the following public attributes:

 -- Attribute: csvreader.dialect

     A read-only description of the dialect in use by the parser.

 -- Attribute: csvreader.line_num

     The number of lines read from the source iterator.  This is not the
     same as the number of records returned, as records can span
     multiple lines.

DictReader objects have the following public attribute:

 -- Attribute: DictReader.fieldnames

     If not passed as a parameter when creating the object, this
     attribute is initialized upon first access or when the first record
     is read from the file.


File: python.info,  Node: Writer Objects,  Next: Examples<10>,  Prev: Reader Objects,  Up: csv — CSV File Reading and Writing

5.14.1.4 Writer Objects
.......................

*note writer: 48a. objects (*note DictWriter: 1243. instances and
objects returned by the *note writer(): 48a. function) have the
following public methods.  A 'row' must be an iterable of strings or
numbers for ‘writer’ objects and a dictionary mapping fieldnames to
strings or numbers (by passing them through *note str(): 44f. first) for
‘DictWriter’ objects.  Note that complex numbers are written out
surrounded by parens.  This may cause some problems for other programs
which read CSV files (assuming they support complex numbers at all).

 -- Method: csvwriter.writerow (row, /)

     Write the 'row' parameter to the writer’s file object, formatted
     according to the current *note Dialect: 178e.  Return the return
     value of the call to the 'write' method of the underlying file
     object.

     Changed in version 3.5: Added support of arbitrary iterables.

 -- Method: csvwriter.writerows (rows, /)

     Write all elements in 'rows' (an iterable of 'row' objects as
     described above) to the writer’s file object, formatted according
     to the current dialect.

Writer objects have the following public attribute:

 -- Attribute: csvwriter.dialect

     A read-only description of the dialect in use by the writer.

DictWriter objects have the following public method:

 -- Method: DictWriter.writeheader ()

     Write a row with the field names (as specified in the constructor)
     to the writer’s file object, formatted according to the current
     dialect.  Return the return value of the *note
     csvwriter.writerow(): e1a. call used internally.

     Added in version 3.2.

     Changed in version 3.8: ‘writeheader()’ now also returns the value
     returned by the *note csvwriter.writerow(): e1a. method it uses
     internally.


File: python.info,  Node: Examples<10>,  Prev: Writer Objects,  Up: csv — CSV File Reading and Writing

5.14.1.5 Examples
.................

The simplest example of reading a CSV file:

     import csv
     with open('some.csv', newline='') as f:
         reader = csv.reader(f)
         for row in reader:
             print(row)

Reading a file with an alternate format:

     import csv
     with open('passwd', newline='') as f:
         reader = csv.reader(f, delimiter=':', quoting=csv.QUOTE_NONE)
         for row in reader:
             print(row)

The corresponding simplest possible writing example is:

     import csv
     with open('some.csv', 'w', newline='') as f:
         writer = csv.writer(f)
         writer.writerows(someiterable)

Since *note open(): 51f. is used to open a CSV file for reading, the
file will by default be decoded into unicode using the system default
encoding (see *note locale.getencoding(): 2dc.).  To decode a file using
a different encoding, use the ‘encoding’ argument of open:

     import csv
     with open('some.csv', newline='', encoding='utf-8') as f:
         reader = csv.reader(f)
         for row in reader:
             print(row)

The same applies to writing in something other than the system default
encoding: specify the encoding argument when opening the output file.

Registering a new dialect:

     import csv
     csv.register_dialect('unixpwd', delimiter=':', quoting=csv.QUOTE_NONE)
     with open('passwd', newline='') as f:
         reader = csv.reader(f, 'unixpwd')

A slightly more advanced use of the reader — catching and reporting
errors:

     import csv, sys
     filename = 'some.csv'
     with open(filename, newline='') as f:
         reader = csv.reader(f)
         try:
             for row in reader:
                 print(row)
         except csv.Error as e:
             sys.exit(f'file {filename}, line {reader.line_num}: {e}')

And while the module doesn’t directly support parsing strings, it can
easily be done:

     import csv
     for row in csv.reader(['one,two,three']):
         print(row)


File: python.info,  Node: configparser — Configuration file parser,  Next: tomllib — Parse TOML files,  Prev: csv — CSV File Reading and Writing,  Up: File Formats

5.14.2 ‘configparser’ — Configuration file parser
-------------------------------------------------

'Source code:' Lib/configparser.py(1)

__________________________________________________________________

This module provides the *note ConfigParser: 1c8. class which implements
a basic configuration language which provides a structure similar to
what’s found in Microsoft Windows INI files.  You can use this to write
Python programs which can be customized by end users easily.

     Note: This library does 'not' interpret or write the value-type
     prefixes used in the Windows Registry extended version of INI
     syntax.

See also
........

Module *note tomllib: fc.

     TOML is a well-specified format for application configuration
     files.  It is specifically designed to be an improved version of
     INI.

Module *note shlex: c4.

     Support for creating Unix shell-like mini-languages which can also
     be used for application configuration files.

Module *note json: 82.

     The ‘json’ module implements a subset of JavaScript syntax which is
     sometimes used for configuration, but does not support comments.

* Menu:

* Quick Start::
* Supported Datatypes::
* Fallback Values::
* Supported INI File Structure::
* Unnamed Sections::
* Interpolation of values::
* Mapping Protocol Access::
* Customizing Parser Behaviour::
* Legacy API Examples::
* ConfigParser Objects::
* RawConfigParser Objects::
* Exceptions: Exceptions<8>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/configparser.py


File: python.info,  Node: Quick Start,  Next: Supported Datatypes,  Up: configparser — Configuration file parser

5.14.2.1 Quick Start
....................

Let’s take a very basic configuration file that looks like this:

     [DEFAULT]
     ServerAliveInterval = 45
     Compression = yes
     CompressionLevel = 9
     ForwardX11 = yes

     [forge.example]
     User = hg

     [topsecret.server.example]
     Port = 50022
     ForwardX11 = no

The structure of INI files is described *note in the following section:
2c6f.  Essentially, the file consists of sections, each of which
contains keys with values.  ‘configparser’ classes can read and write
such files.  Let’s start by creating the above configuration file
programmatically.

     >>> import configparser
     >>> config = configparser.ConfigParser()
     >>> config['DEFAULT'] = {'ServerAliveInterval': '45',
     ...                      'Compression': 'yes',
     ...                      'CompressionLevel': '9'}
     >>> config['forge.example'] = {}
     >>> config['forge.example']['User'] = 'hg'
     >>> config['topsecret.server.example'] = {}
     >>> topsecret = config['topsecret.server.example']
     >>> topsecret['Port'] = '50022'     # mutates the parser
     >>> topsecret['ForwardX11'] = 'no'  # same here
     >>> config['DEFAULT']['ForwardX11'] = 'yes'
     >>> with open('example.ini', 'w') as configfile:
     ...   config.write(configfile)
     ...

As you can see, we can treat a config parser much like a dictionary.
There are differences, *note outlined later: 2c70, but the behavior is
very close to what you would expect from a dictionary.

Now that we have created and saved a configuration file, let’s read it
back and explore the data it holds.

     >>> config = configparser.ConfigParser()
     >>> config.sections()
     []
     >>> config.read('example.ini')
     ['example.ini']
     >>> config.sections()
     ['forge.example', 'topsecret.server.example']
     >>> 'forge.example' in config
     True
     >>> 'python.org' in config
     False
     >>> config['forge.example']['User']
     'hg'
     >>> config['DEFAULT']['Compression']
     'yes'
     >>> topsecret = config['topsecret.server.example']
     >>> topsecret['ForwardX11']
     'no'
     >>> topsecret['Port']
     '50022'
     >>> for key in config['forge.example']:
     ...     print(key)
     user
     compressionlevel
     serveraliveinterval
     compression
     forwardx11
     >>> config['forge.example']['ForwardX11']
     'yes'

As we can see above, the API is pretty straightforward.  The only bit of
magic involves the ‘DEFAULT’ section which provides default values for
all other sections (1).  Note also that keys in sections are
case-insensitive and stored in lowercase (2).

It is possible to read several configurations into a single *note
ConfigParser: 1c8, where the most recently added configuration has the
highest priority.  Any conflicting keys are taken from the more recent
configuration while the previously existing keys are retained.  The
example below reads in an ‘override.ini’ file, which will override any
conflicting keys from the ‘example.ini’ file.

     [DEFAULT]
     ServerAliveInterval = -1

     >>> config_override = configparser.ConfigParser()
     >>> config_override['DEFAULT'] = {'ServerAliveInterval': '-1'}
     >>> with open('override.ini', 'w') as configfile:
     ...     config_override.write(configfile)
     ...
     >>> config_override = configparser.ConfigParser()
     >>> config_override.read(['example.ini', 'override.ini'])
     ['example.ini', 'override.ini']
     >>> print(config_override.get('DEFAULT', 'ServerAliveInterval'))
     -1

This behaviour is equivalent to a *note ConfigParser.read(): 14b7. call
with several files passed to the 'filenames' parameter.

   ---------- Footnotes ----------

   (1) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (2) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.


File: python.info,  Node: Supported Datatypes,  Next: Fallback Values,  Prev: Quick Start,  Up: configparser — Configuration file parser

5.14.2.2 Supported Datatypes
............................

Config parsers do not guess datatypes of values in configuration files,
always storing them internally as strings.  This means that if you need
other datatypes, you should convert on your own:

     >>> int(topsecret['Port'])
     50022
     >>> float(topsecret['CompressionLevel'])
     9.0

Since this task is so common, config parsers provide a range of handy
getter methods to handle integers, floats and booleans.  The last one is
the most interesting because simply passing the value to ‘bool()’ would
do no good since ‘bool('False')’ is still ‘True’.  This is why config
parsers also provide *note getboolean(): 2c73.  This method is
case-insensitive and recognizes Boolean values from ‘'yes'’/‘'no'’,
‘'on'’/‘'off'’, ‘'true'’/‘'false'’ and ‘'1'’/‘'0'’ (1).  For example:

     >>> topsecret.getboolean('ForwardX11')
     False
     >>> config['forge.example'].getboolean('ForwardX11')
     True
     >>> config.getboolean('forge.example', 'Compression')
     True

Apart from *note getboolean(): 2c73, config parsers also provide
equivalent *note getint(): 2c74. and *note getfloat(): 2c75. methods.
You can register your own converters and customize the provided ones.
(2)

   ---------- Footnotes ----------

   (1) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (2) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.


File: python.info,  Node: Fallback Values,  Next: Supported INI File Structure,  Prev: Supported Datatypes,  Up: configparser — Configuration file parser

5.14.2.3 Fallback Values
........................

As with a dictionary, you can use a section’s *note get(): 12b2. method
to provide fallback values:

     >>> topsecret.get('Port')
     '50022'
     >>> topsecret.get('CompressionLevel')
     '9'
     >>> topsecret.get('Cipher')
     >>> topsecret.get('Cipher', '3des-cbc')
     '3des-cbc'

Please note that default values have precedence over fallback values.
For instance, in our example the ‘'CompressionLevel'’ key was specified
only in the ‘'DEFAULT'’ section.  If we try to get it from the section
‘'topsecret.server.example'’, we will always get the default, even if we
specify a fallback:

     >>> topsecret.get('CompressionLevel', '3')
     '9'

One more thing to be aware of is that the parser-level *note get():
12b2. method provides a custom, more complex interface, maintained for
backwards compatibility.  When using this method, a fallback value can
be provided via the ‘fallback’ keyword-only argument:

     >>> config.get('forge.example', 'monster',
     ...            fallback='No such things as monsters')
     'No such things as monsters'

The same ‘fallback’ argument can be used with the *note getint(): 2c74,
*note getfloat(): 2c75. and *note getboolean(): 2c73. methods, for
example:

     >>> 'BatchMode' in topsecret
     False
     >>> topsecret.getboolean('BatchMode', fallback=True)
     True
     >>> config['DEFAULT']['BatchMode'] = 'no'
     >>> topsecret.getboolean('BatchMode', fallback=True)
     False


File: python.info,  Node: Supported INI File Structure,  Next: Unnamed Sections,  Prev: Fallback Values,  Up: configparser — Configuration file parser

5.14.2.4 Supported INI File Structure
.....................................

A configuration file consists of sections, each led by a ‘[section]’
header, followed by key/value entries separated by a specific string
(‘=’ or ‘:’ by default (1)).  By default, section names are case
sensitive but keys are not (2).  Leading and trailing whitespace is
removed from keys and values.  Values can be omitted if the parser is
configured to allow it (3), in which case the key/value delimiter may
also be left out.  Values can also span multiple lines, as long as they
are indented deeper than the first line of the value.  Depending on the
parser’s mode, blank lines may be treated as parts of multiline values
or ignored.

By default, a valid section name can be any string that does not contain
‘\n’.  To change this, see *note ConfigParser.SECTCRE: 2c77.

The first section name may be omitted if the parser is configured to
allow an unnamed top level section with ‘allow_unnamed_section=True’.
In this case, the keys/values may be retrieved by *note UNNAMED_SECTION:
2c78. as in ‘config[UNNAMED_SECTION]’.

Configuration files may include comments, prefixed by specific
characters (‘#’ and ‘;’ by default (4)).  Comments may appear on their
own on an otherwise empty line, possibly indented.  (5)

For example:

     [Simple Values]
     key=value
     spaces in keys=allowed
     spaces in values=allowed as well
     spaces around the delimiter = obviously
     you can also use : to delimit keys from values

     [All Values Are Strings]
     values like this: 1000000
     or this: 3.14159265359
     are they treated as numbers? : no
     integers, floats and booleans are held as: strings
     can use the API to get converted values directly: true

     [Multiline Values]
     chorus: I'm a lumberjack, and I'm okay
         I sleep all night and I work all day

     [No Values]
     key_without_value
     empty string value here =

     [You can use comments]
     # like this
     ; or this

     # By default only in an empty line.
     # Inline comments can be harmful because they prevent users
     # from using the delimiting characters as parts of values.
     # That being said, this can be customized.

         [Sections Can Be Indented]
             can_values_be_as_well = True
             does_that_mean_anything_special = False
             purpose = formatting for readability
             multiline_values = are
                 handled just fine as
                 long as they are indented
                 deeper than the first line
                 of a value
             # Did I mention we can indent comments, too?

   ---------- Footnotes ----------

   (1) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (2) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (3) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (4) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.

   (5) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.


File: python.info,  Node: Unnamed Sections,  Next: Interpolation of values,  Prev: Supported INI File Structure,  Up: configparser — Configuration file parser

5.14.2.5 Unnamed Sections
.........................

The name of the first section (or unique) may be omitted and values
retrieved by the *note UNNAMED_SECTION: 2c78. attribute.

     >>> config = """
     ... option = value
     ...
     ... [  Section 2  ]
     ... another = val
     ... """
     >>> unnamed = configparser.ConfigParser(allow_unnamed_section=True)
     >>> unnamed.read_string(config)
     >>> unnamed.get(configparser.UNNAMED_SECTION, 'option')
     'value'


File: python.info,  Node: Interpolation of values,  Next: Mapping Protocol Access,  Prev: Unnamed Sections,  Up: configparser — Configuration file parser

5.14.2.6 Interpolation of values
................................

On top of the core functionality, *note ConfigParser: 1c8. supports
interpolation.  This means values can be preprocessed before returning
them from ‘get()’ calls.

 -- Class: configparser.BasicInterpolation

     The default implementation used by *note ConfigParser: 1c8.  It
     enables values to contain format strings which refer to other
     values in the same section, or values in the special default
     section (1).  Additional default values can be provided on
     initialization.

     For example:

          [Paths]
          home_dir: /Users
          my_dir: %(home_dir)s/lumberjack
          my_pictures: %(my_dir)s/Pictures

          [Escape]
          # use a %% to escape the % sign (% is the only character that needs to be escaped):
          gain: 80%%

     In the example above, *note ConfigParser: 1c8. with 'interpolation'
     set to ‘BasicInterpolation()’ would resolve ‘%(home_dir)s’ to the
     value of ‘home_dir’ (‘/Users’ in this case).  ‘%(my_dir)s’ in
     effect would resolve to ‘/Users/lumberjack’.  All interpolations
     are done on demand so keys used in the chain of references do not
     have to be specified in any specific order in the configuration
     file.

     With ‘interpolation’ set to ‘None’, the parser would simply return
     ‘%(my_dir)s/Pictures’ as the value of ‘my_pictures’ and
     ‘%(home_dir)s/lumberjack’ as the value of ‘my_dir’.

 -- Class: configparser.ExtendedInterpolation

     An alternative handler for interpolation which implements a more
     advanced syntax, used for instance in ‘zc.buildout’.  Extended
     interpolation is using ‘${section:option}’ to denote a value from a
     foreign section.  Interpolation can span multiple levels.  For
     convenience, if the ‘section:’ part is omitted, interpolation
     defaults to the current section (and possibly the default values
     from the special section).

     For example, the configuration specified above with basic
     interpolation, would look like this with extended interpolation:

          [Paths]
          home_dir: /Users
          my_dir: ${home_dir}/lumberjack
          my_pictures: ${my_dir}/Pictures

          [Escape]
          # use a $$ to escape the $ sign ($ is the only character that needs to be escaped):
          cost: $$80

     Values from other sections can be fetched as well:

          [Common]
          home_dir: /Users
          library_dir: /Library
          system_dir: /System
          macports_dir: /opt/local

          [Frameworks]
          Python: 3.2
          path: ${Common:system_dir}/Library/Frameworks/

          [Arthur]
          nickname: Two Sheds
          last_name: Jackson
          my_dir: ${Common:home_dir}/twosheds
          my_pictures: ${my_dir}/Pictures
          python_dir: ${Frameworks:path}/Python/Versions/${Frameworks:Python}

   ---------- Footnotes ----------

   (1) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.


File: python.info,  Node: Mapping Protocol Access,  Next: Customizing Parser Behaviour,  Prev: Interpolation of values,  Up: configparser — Configuration file parser

5.14.2.7 Mapping Protocol Access
................................

Added in version 3.2.

Mapping protocol access is a generic name for functionality that enables
using custom objects as if they were dictionaries.  In case of
‘configparser’, the mapping interface implementation is using the
‘parser['section']['option']’ notation.

‘parser['section']’ in particular returns a proxy for the section’s data
in the parser.  This means that the values are not copied but they are
taken from the original parser on demand.  What’s even more important is
that when values are changed on a section proxy, they are actually
mutated in the original parser.

‘configparser’ objects behave as close to actual dictionaries as
possible.  The mapping interface is complete and adheres to the *note
MutableMapping: 10f0. ABC. However, there are a few differences that
should be taken into account:

   * By default, all keys in sections are accessible in a
     case-insensitive manner (1).  E.g.  ‘for option in
     parser["section"]’ yields only ‘optionxform’’ed option key names.
     This means lowercased keys by default.  At the same time, for a
     section that holds the key ‘'a'’, both expressions return ‘True’:

          "a" in parser["section"]
          "A" in parser["section"]

   * All sections include ‘DEFAULTSECT’ values as well which means that
     ‘.clear()’ on a section may not leave the section visibly empty.
     This is because default values cannot be deleted from the section
     (because technically they are not there).  If they are overridden
     in the section, deleting causes the default value to be visible
     again.  Trying to delete a default value causes a *note KeyError:
     345.

   * ‘DEFAULTSECT’ cannot be removed from the parser:

        * trying to delete it raises *note ValueError: 202,

        * ‘parser.clear()’ leaves it intact,

        * ‘parser.popitem()’ never returns it.

   * ‘parser.get(section, option, **kwargs)’ - the second argument is
     'not' a fallback value.  Note however that the section-level
     ‘get()’ methods are compatible both with the mapping protocol and
     the classic configparser API.

   * ‘parser.items()’ is compatible with the mapping protocol (returns a
     list of 'section_name', 'section_proxy' pairs including the
     DEFAULTSECT). However, this method can also be invoked with
     arguments: ‘parser.items(section, raw, vars)’.  The latter call
     returns a list of 'option', 'value' pairs for a specified
     ‘section’, with all interpolations expanded (unless ‘raw=True’ is
     provided).

The mapping protocol is implemented on top of the existing legacy API so
that subclasses overriding the original interface still should have
mappings working as expected.

   ---------- Footnotes ----------

   (1) Config parsers allow for heavy customization.  If you are
interested in changing the behaviour outlined by the footnote reference,
consult the *note Customizing Parser Behaviour: 2c71. section.


File: python.info,  Node: Customizing Parser Behaviour,  Next: Legacy API Examples,  Prev: Mapping Protocol Access,  Up: configparser — Configuration file parser

5.14.2.8 Customizing Parser Behaviour
.....................................

There are nearly as many INI format variants as there are applications
using it.  ‘configparser’ goes a long way to provide support for the
largest sensible set of INI styles available.  The default functionality
is mainly dictated by historical background and it’s very likely that
you will want to customize some of the features.

The most common way to change the way a specific config parser works is
to use the ‘__init__()’ options:

   * 'defaults', default value: ‘None’

     This option accepts a dictionary of key-value pairs which will be
     initially put in the ‘DEFAULT’ section.  This makes for an elegant
     way to support concise configuration files that don’t specify
     values which are the same as the documented default.

     Hint: if you want to specify default values for a specific section,
     use *note read_dict(): 2c7c. before you read the actual file.

   * 'dict_type', default value: *note dict: 256.

     This option has a major impact on how the mapping protocol will
     behave and how the written configuration files look.  With the
     standard dictionary, every section is stored in the order they were
     added to the parser.  Same goes for options within sections.

     An alternative dictionary type can be used for example to sort
     sections and options on write-back.

     Please note: there are ways to add a set of key-value pairs in a
     single operation.  When you use a regular dictionary in those
     operations, the order of the keys will be ordered.  For example:

          >>> parser = configparser.ConfigParser()
          >>> parser.read_dict({'section1': {'key1': 'value1',
          ...                                'key2': 'value2',
          ...                                'key3': 'value3'},
          ...                   'section2': {'keyA': 'valueA',
          ...                                'keyB': 'valueB',
          ...                                'keyC': 'valueC'},
          ...                   'section3': {'foo': 'x',
          ...                                'bar': 'y',
          ...                                'baz': 'z'}
          ... })
          >>> parser.sections()
          ['section1', 'section2', 'section3']
          >>> [option for option in parser['section3']]
          ['foo', 'bar', 'baz']

   * 'allow_no_value', default value: ‘False’

     Some configuration files are known to include settings without
     values, but which otherwise conform to the syntax supported by
     ‘configparser’.  The 'allow_no_value' parameter to the constructor
     can be used to indicate that such values should be accepted:

          >>> import configparser

          >>> sample_config = """
          ... [mysqld]
          ...   user = mysql
          ...   pid-file = /var/run/mysqld/mysqld.pid
          ...   skip-external-locking
          ...   old_passwords = 1
          ...   skip-bdb
          ...   # we don't need ACID today
          ...   skip-innodb
          ... """
          >>> config = configparser.ConfigParser(allow_no_value=True)
          >>> config.read_string(sample_config)

          >>> # Settings with values are treated as before:
          >>> config["mysqld"]["user"]
          'mysql'

          >>> # Settings without values provide None:
          >>> config["mysqld"]["skip-bdb"]

          >>> # Settings which aren't specified still raise an error:
          >>> config["mysqld"]["does-not-exist"]
          Traceback (most recent call last):
            ...
          KeyError: 'does-not-exist'

   * 'delimiters', default value: ‘('=', ':')’

     Delimiters are substrings that delimit keys from values within a
     section.  The first occurrence of a delimiting substring on a line
     is considered a delimiter.  This means values (but not keys) can
     contain the delimiters.

     See also the 'space_around_delimiters' argument to *note
     ConfigParser.write(): 2c7d.

   * 'comment_prefixes', default value: ‘('#', ';')’

   * 'inline_comment_prefixes', default value: ‘None’

     Comment prefixes are strings that indicate the start of a valid
     comment within a config file.  'comment_prefixes' are used only on
     otherwise empty lines (optionally indented) whereas
     'inline_comment_prefixes' can be used after every valid value (e.g.
     section names, options and empty lines as well).  By default inline
     comments are disabled and ‘'#'’ and ‘';'’ are used as prefixes for
     whole line comments.

     Changed in version 3.2: In previous versions of ‘configparser’
     behaviour matched ‘comment_prefixes=('#',';')’ and
     ‘inline_comment_prefixes=(';',)’.

     Please note that config parsers don’t support escaping of comment
     prefixes so using 'inline_comment_prefixes' may prevent users from
     specifying option values with characters used as comment prefixes.
     When in doubt, avoid setting 'inline_comment_prefixes'.  In any
     circumstances, the only way of storing comment prefix characters at
     the beginning of a line in multiline values is to interpolate the
     prefix, for example:

          >>> from configparser import ConfigParser, ExtendedInterpolation
          >>> parser = ConfigParser(interpolation=ExtendedInterpolation())
          >>> # the default BasicInterpolation could be used as well
          >>> parser.read_string("""
          ... [DEFAULT]
          ... hash = #
          ...
          ... [hashes]
          ... shebang =
          ...   ${hash}!/usr/bin/env python
          ...   ${hash} -*- coding: utf-8 -*-
          ...
          ... extensions =
          ...   enabled_extension
          ...   another_extension
          ...   #disabled_by_comment
          ...   yet_another_extension
          ...
          ... interpolation not necessary = if # is not at line start
          ... even in multiline values = line #1
          ...   line #2
          ...   line #3
          ... """)
          >>> print(parser['hashes']['shebang'])

          #!/usr/bin/env python
          # -*- coding: utf-8 -*-
          >>> print(parser['hashes']['extensions'])

          enabled_extension
          another_extension
          yet_another_extension
          >>> print(parser['hashes']['interpolation not necessary'])
          if # is not at line start
          >>> print(parser['hashes']['even in multiline values'])
          line #1
          line #2
          line #3

   * 'strict', default value: ‘True’

     When set to ‘True’, the parser will not allow for any section or
     option duplicates while reading from a single source (using *note
     read_file(): 509, *note read_string(): 2c7e. or *note read_dict():
     2c7c.).  It is recommended to use strict parsers in new
     applications.

     Changed in version 3.2: In previous versions of ‘configparser’
     behaviour matched ‘strict=False’.

   * 'empty_lines_in_values', default value: ‘True’

     In config parsers, values can span multiple lines as long as they
     are indented more than the key that holds them.  By default parsers
     also let empty lines to be parts of values.  At the same time, keys
     can be arbitrarily indented themselves to improve readability.  In
     consequence, when configuration files get big and complex, it is
     easy for the user to lose track of the file structure.  Take for
     instance:

          [Section]
          key = multiline
            value with a gotcha

           this = is still a part of the multiline value of 'key'

     This can be especially problematic for the user to see if she’s
     using a proportional font to edit the file.  That is why when your
     application does not need values with empty lines, you should
     consider disallowing them.  This will make empty lines split keys
     every time.  In the example above, it would produce two keys, ‘key’
     and ‘this’.

   * 'default_section', default value: ‘configparser.DEFAULTSECT’ (that
     is: ‘"DEFAULT"’)

     The convention of allowing a special section of default values for
     other sections or interpolation purposes is a powerful concept of
     this library, letting users create complex declarative
     configurations.  This section is normally called ‘"DEFAULT"’ but
     this can be customized to point to any other valid section name.
     Some typical values include: ‘"general"’ or ‘"common"’.  The name
     provided is used for recognizing default sections when reading from
     any source and is used when writing configuration back to a file.
     Its current value can be retrieved using the
     ‘parser_instance.default_section’ attribute and may be modified at
     runtime (i.e.  to convert files from one format to another).

   * 'interpolation', default value: ‘configparser.BasicInterpolation’

     Interpolation behaviour may be customized by providing a custom
     handler through the 'interpolation' argument.  ‘None’ can be used
     to turn off interpolation completely, ‘ExtendedInterpolation()’
     provides a more advanced variant inspired by ‘zc.buildout’.  More
     on the subject in the *note dedicated documentation section: 2c7b.
     *note RawConfigParser: f9d. has a default value of ‘None’.

   * 'converters', default value: not set

     Config parsers provide option value getters that perform type
     conversion.  By default *note getint(): 2c74, *note getfloat():
     2c75, and *note getboolean(): 2c73. are implemented.  Should other
     getters be desirable, users may define them in a subclass or pass a
     dictionary where each key is a name of the converter and each value
     is a callable implementing said conversion.  For instance, passing
     ‘{'decimal': decimal.Decimal}’ would add ‘getdecimal()’ on both the
     parser object and all section proxies.  In other words, it will be
     possible to write both ‘parser_instance.getdecimal('section',
     'key', fallback=0)’ and
     ‘parser_instance['section'].getdecimal('key', 0)’.

     If the converter needs to access the state of the parser, it can be
     implemented as a method on a config parser subclass.  If the name
     of this method starts with ‘get’, it will be available on all
     section proxies, in the dict-compatible form (see the
     ‘getdecimal()’ example above).

More advanced customization may be achieved by overriding default values
of these parser attributes.  The defaults are defined on the classes, so
they may be overridden by subclasses or by attribute assignment.

 -- Attribute: ConfigParser.BOOLEAN_STATES

     By default when using *note getboolean(): 2c73, config parsers
     consider the following values ‘True’: ‘'1'’, ‘'yes'’, ‘'true'’,
     ‘'on'’ and the following values ‘False’: ‘'0'’, ‘'no'’, ‘'false'’,
     ‘'off'’.  You can override this by specifying a custom dictionary
     of strings and their Boolean outcomes.  For example:

          >>> custom = configparser.ConfigParser()
          >>> custom['section1'] = {'funky': 'nope'}
          >>> custom['section1'].getboolean('funky')
          Traceback (most recent call last):
          ...
          ValueError: Not a boolean: nope
          >>> custom.BOOLEAN_STATES = {'sure': True, 'nope': False}
          >>> custom['section1'].getboolean('funky')
          False

     Other typical Boolean pairs include ‘accept’/‘reject’ or
     ‘enabled’/‘disabled’.

 -- Method: ConfigParser.optionxform (option)

     This method transforms option names on every read, get, or set
     operation.  The default converts the name to lowercase.  This also
     means that when a configuration file gets written, all keys will be
     lowercase.  Override this method if that’s unsuitable.  For
     example:

          >>> config = """
          ... [Section1]
          ... Key = Value
          ...
          ... [Section2]
          ... AnotherKey = Value
          ... """
          >>> typical = configparser.ConfigParser()
          >>> typical.read_string(config)
          >>> list(typical['Section1'].keys())
          ['key']
          >>> list(typical['Section2'].keys())
          ['anotherkey']
          >>> custom = configparser.RawConfigParser()
          >>> custom.optionxform = lambda option: option
          >>> custom.read_string(config)
          >>> list(custom['Section1'].keys())
          ['Key']
          >>> list(custom['Section2'].keys())
          ['AnotherKey']

          Note: The optionxform function transforms option names to a
          canonical form.  This should be an idempotent function: if the
          name is already in canonical form, it should be returned
          unchanged.

 -- Attribute: ConfigParser.SECTCRE

     A compiled regular expression used to parse section headers.  The
     default matches ‘[section]’ to the name ‘"section"’.  Whitespace is
     considered part of the section name, thus ‘[ larch ]’ will be read
     as a section of name ‘" larch "’.  Override this attribute if
     that’s unsuitable.  For example:

          >>> import re
          >>> config = """
          ... [Section 1]
          ... option = value
          ...
          ... [  Section 2  ]
          ... another = val
          ... """
          >>> typical = configparser.ConfigParser()
          >>> typical.read_string(config)
          >>> typical.sections()
          ['Section 1', '  Section 2  ']
          >>> custom = configparser.ConfigParser()
          >>> custom.SECTCRE = re.compile(r"\[ *(?P<header>[^]]+?) *\]")
          >>> custom.read_string(config)
          >>> custom.sections()
          ['Section 1', 'Section 2']

          Note: While ConfigParser objects also use an ‘OPTCRE’
          attribute for recognizing option lines, it’s not recommended
          to override it because that would interfere with constructor
          options 'allow_no_value' and 'delimiters'.


File: python.info,  Node: Legacy API Examples,  Next: ConfigParser Objects,  Prev: Customizing Parser Behaviour,  Up: configparser — Configuration file parser

5.14.2.9 Legacy API Examples
............................

Mainly because of backwards compatibility concerns, ‘configparser’
provides also a legacy API with explicit ‘get’/‘set’ methods.  While
there are valid use cases for the methods outlined below, mapping
protocol access is preferred for new projects.  The legacy API is at
times more advanced, low-level and downright counterintuitive.

An example of writing to a configuration file:

     import configparser

     config = configparser.RawConfigParser()

     # Please note that using RawConfigParser's set functions, you can assign
     # non-string values to keys internally, but will receive an error when
     # attempting to write to a file or when you get it in non-raw mode. Setting
     # values using the mapping protocol or ConfigParser's set() does not allow
     # such assignments to take place.
     config.add_section('Section1')
     config.set('Section1', 'an_int', '15')
     config.set('Section1', 'a_bool', 'true')
     config.set('Section1', 'a_float', '3.1415')
     config.set('Section1', 'baz', 'fun')
     config.set('Section1', 'bar', 'Python')
     config.set('Section1', 'foo', '%(bar)s is %(baz)s!')

     # Writing our configuration file to 'example.cfg'
     with open('example.cfg', 'w') as configfile:
         config.write(configfile)

An example of reading the configuration file again:

     import configparser

     config = configparser.RawConfigParser()
     config.read('example.cfg')

     # getfloat() raises an exception if the value is not a float
     # getint() and getboolean() also do this for their respective types
     a_float = config.getfloat('Section1', 'a_float')
     an_int = config.getint('Section1', 'an_int')
     print(a_float + an_int)

     # Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'.
     # This is because we are using a RawConfigParser().
     if config.getboolean('Section1', 'a_bool'):
         print(config.get('Section1', 'foo'))

To get interpolation, use *note ConfigParser: 1c8.:

     import configparser

     cfg = configparser.ConfigParser()
     cfg.read('example.cfg')

     # Set the optional *raw* argument of get() to True if you wish to disable
     # interpolation in a single get operation.
     print(cfg.get('Section1', 'foo', raw=False))  # -> "Python is fun!"
     print(cfg.get('Section1', 'foo', raw=True))   # -> "%(bar)s is %(baz)s!"

     # The optional *vars* argument is a dict with members that will take
     # precedence in interpolation.
     print(cfg.get('Section1', 'foo', vars={'bar': 'Documentation',
                                            'baz': 'evil'}))

     # The optional *fallback* argument can be used to provide a fallback value
     print(cfg.get('Section1', 'foo'))
           # -> "Python is fun!"

     print(cfg.get('Section1', 'foo', fallback='Monty is not.'))
           # -> "Python is fun!"

     print(cfg.get('Section1', 'monster', fallback='No such things as monsters.'))
           # -> "No such things as monsters."

     # A bare print(cfg.get('Section1', 'monster')) would raise NoOptionError
     # but we can also use:

     print(cfg.get('Section1', 'monster', fallback=None))
           # -> None

Default values are available in both types of ConfigParsers.  They are
used in interpolation if an option used is not defined elsewhere.

     import configparser

     # New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' each
     config = configparser.ConfigParser({'bar': 'Life', 'baz': 'hard'})
     config.read('example.cfg')

     print(config.get('Section1', 'foo'))     # -> "Python is fun!"
     config.remove_option('Section1', 'bar')
     config.remove_option('Section1', 'baz')
     print(config.get('Section1', 'foo'))     # -> "Life is hard!"


File: python.info,  Node: ConfigParser Objects,  Next: RawConfigParser Objects,  Prev: Legacy API Examples,  Up: configparser — Configuration file parser

5.14.2.10 ConfigParser Objects
..............................

 -- Class: configparser.ConfigParser (defaults=None, dict_type=dict,
          allow_no_value=False, *, delimiters=('=', ':'),
          comment_prefixes=('#', ';'), inline_comment_prefixes=None,
          strict=True, empty_lines_in_values=True,
          default_section=configparser.DEFAULTSECT,
          interpolation=BasicInterpolation(), converters={},
          allow_unnamed_section=False)

     The main configuration parser.  When 'defaults' is given, it is
     initialized into the dictionary of intrinsic defaults.  When
     'dict_type' is given, it will be used to create the dictionary
     objects for the list of sections, for the options within a section,
     and for the default values.

     When 'delimiters' is given, it is used as the set of substrings
     that divide keys from values.  When 'comment_prefixes' is given, it
     will be used as the set of substrings that prefix comments in
     otherwise empty lines.  Comments can be indented.  When
     'inline_comment_prefixes' is given, it will be used as the set of
     substrings that prefix comments in non-empty lines.

     When 'strict' is ‘True’ (the default), the parser won’t allow for
     any section or option duplicates while reading from a single source
     (file, string or dictionary), raising *note DuplicateSectionError:
     12b5. or *note DuplicateOptionError: 12b6.  When
     'empty_lines_in_values' is ‘False’ (default: ‘True’), each empty
     line marks the end of an option.  Otherwise, internal empty lines
     of a multiline option are kept as part of the value.  When
     'allow_no_value' is ‘True’ (default: ‘False’), options without
     values are accepted; the value held for these is ‘None’ and they
     are serialized without the trailing delimiter.

     When 'default_section' is given, it specifies the name for the
     special section holding default values for other sections and
     interpolation purposes (normally named ‘"DEFAULT"’).  This value
     can be retrieved and changed at runtime using the ‘default_section’
     instance attribute.  This won’t re-evaluate an already parsed
     config file, but will be used when writing parsed settings to a new
     config file.

     Interpolation behaviour may be customized by providing a custom
     handler through the 'interpolation' argument.  ‘None’ can be used
     to turn off interpolation completely, ‘ExtendedInterpolation()’
     provides a more advanced variant inspired by ‘zc.buildout’.  More
     on the subject in the *note dedicated documentation section: 2c7b.

     All option names used in interpolation will be passed through the
     *note optionxform(): 2c83. method just like any other option name
     reference.  For example, using the default implementation of
     ‘optionxform()’ (which converts option names to lower case), the
     values ‘foo %(bar)s’ and ‘foo %(BAR)s’ are equivalent.

     When 'converters' is given, it should be a dictionary where each
     key represents the name of a type converter and each value is a
     callable implementing the conversion from string to the desired
     datatype.  Every converter gets its own corresponding ‘get*()’
     method on the parser object and section proxies.

     When 'allow_unnamed_section' is ‘True’ (default: ‘False’), the
     first section name can be omitted.  See the *note "Unnamed
     Sections" section: 2c7a.

     It is possible to read several configurations into a single
     ‘ConfigParser’, where the most recently added configuration has the
     highest priority.  Any conflicting keys are taken from the more
     recent configuration while the previously existing keys are
     retained.  The example below reads in an ‘override.ini’ file, which
     will override any conflicting keys from the ‘example.ini’ file.

          [DEFAULT]
          ServerAliveInterval = -1

          >>> config_override = configparser.ConfigParser()
          >>> config_override['DEFAULT'] = {'ServerAliveInterval': '-1'}
          >>> with open('override.ini', 'w') as configfile:
          ...     config_override.write(configfile)
          ...
          >>> config_override = configparser.ConfigParser()
          >>> config_override.read(['example.ini', 'override.ini'])
          ['example.ini', 'override.ini']
          >>> print(config_override.get('DEFAULT', 'ServerAliveInterval'))
          -1

     Changed in version 3.1: The default 'dict_type' is *note
     collections.OrderedDict: 5de.

     Changed in version 3.2: 'allow_no_value', 'delimiters',
     'comment_prefixes', 'strict', 'empty_lines_in_values',
     'default_section' and 'interpolation' were added.

     Changed in version 3.5: The 'converters' argument was added.

     Changed in version 3.7: The 'defaults' argument is read with *note
     read_dict(): 2c7c, providing consistent behavior across the parser:
     non-string keys and values are implicitly converted to strings.

     Changed in version 3.8: The default 'dict_type' is *note dict: 256,
     since it now preserves insertion order.

     Changed in version 3.13: Raise a *note MultilineContinuationError:
     2c84. when 'allow_no_value' is ‘True’, and a key without a value is
     continued with an indented line.

     Changed in version 3.13: The 'allow_unnamed_section' argument was
     added.

      -- Method: defaults ()

          Return a dictionary containing the instance-wide defaults.

      -- Method: sections ()

          Return a list of the sections available; the 'default section'
          is not included in the list.

      -- Method: add_section (section)

          Add a section named 'section' to the instance.  If a section
          by the given name already exists, *note DuplicateSectionError:
          12b5. is raised.  If the 'default section' name is passed,
          *note ValueError: 202. is raised.  The name of the section
          must be a string; if not, *note TypeError: 2c3. is raised.

          Changed in version 3.2: Non-string section names raise *note
          TypeError: 2c3.

      -- Method: has_section (section)

          Indicates whether the named 'section' is present in the
          configuration.  The 'default section' is not acknowledged.

      -- Method: options (section)

          Return a list of options available in the specified 'section'.

      -- Method: has_option (section, option)

          If the given 'section' exists, and contains the given
          'option', return *note True: c2d.; otherwise return *note
          False: b4f.  If the specified 'section' is *note None: 678. or
          an empty string, DEFAULT is assumed.

      -- Method: read (filenames, encoding=None)

          Attempt to read and parse an iterable of filenames, returning
          a list of filenames which were successfully parsed.

          If 'filenames' is a string, a *note bytes: 1c2. object or a
          *note path-like object: 2a0, it is treated as a single
          filename.  If a file named in 'filenames' cannot be opened,
          that file will be ignored.  This is designed so that you can
          specify an iterable of potential configuration file locations
          (for example, the current directory, the user’s home
          directory, and some system-wide directory), and all existing
          configuration files in the iterable will be read.

          If none of the named files exist, the ‘ConfigParser’ instance
          will contain an empty dataset.  An application which requires
          initial values to be loaded from a file should load the
          required file or files using *note read_file(): 509. before
          calling ‘read()’ for any optional files:

               import configparser, os

               config = configparser.ConfigParser()
               config.read_file(open('defaults.cfg'))
               config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')],
                           encoding='cp1250')

          Changed in version 3.2: Added the 'encoding' parameter.
          Previously, all files were read using the default encoding for
          *note open(): 51f.

          Changed in version 3.6.1: The 'filenames' parameter accepts a
          *note path-like object: 2a0.

          Changed in version 3.7: The 'filenames' parameter accepts a
          *note bytes: 1c2. object.

      -- Method: read_file (f, source=None)

          Read and parse configuration data from 'f' which must be an
          iterable yielding Unicode strings (for example files opened in
          text mode).

          Optional argument 'source' specifies the name of the file
          being read.  If not given and 'f' has a ‘name’ attribute, that
          is used for 'source'; the default is ‘'<???>'’.

          Added in version 3.2: Replaces ‘readfp()’.

      -- Method: read_string (string, source='<string>')

          Parse configuration data from a string.

          Optional argument 'source' specifies a context-specific name
          of the string passed.  If not given, ‘'<string>'’ is used.
          This should commonly be a filesystem path or a URL.

          Added in version 3.2.

      -- Method: read_dict (dictionary, source='<dict>')

          Load configuration from any object that provides a dict-like
          ‘items()’ method.  Keys are section names, values are
          dictionaries with keys and values that should be present in
          the section.  If the used dictionary type preserves order,
          sections and their keys will be added in order.  Values are
          automatically converted to strings.

          Optional argument 'source' specifies a context-specific name
          of the dictionary passed.  If not given, ‘<dict>’ is used.

          This method can be used to copy state between parsers.

          Added in version 3.2.

      -- Method: get (section, option, *, raw=False, vars=None[,
               fallback])

          Get an 'option' value for the named 'section'.  If 'vars' is
          provided, it must be a dictionary.  The 'option' is looked up
          in 'vars' (if provided), 'section', and in 'DEFAULTSECT' in
          that order.  If the key is not found and 'fallback' is
          provided, it is used as a fallback value.  ‘None’ can be
          provided as a 'fallback' value.

          All the ‘'%'’ interpolations are expanded in the return
          values, unless the 'raw' argument is true.  Values for
          interpolation keys are looked up in the same manner as the
          option.

          Changed in version 3.2: Arguments 'raw', 'vars' and 'fallback'
          are keyword only to protect users from trying to use the third
          argument as the 'fallback' fallback (especially when using the
          mapping protocol).

      -- Method: getint (section, option, *, raw=False, vars=None[,
               fallback])

          A convenience method which coerces the 'option' in the
          specified 'section' to an integer.  See *note get(): 12b2. for
          explanation of 'raw', 'vars' and 'fallback'.

      -- Method: getfloat (section, option, *, raw=False, vars=None[,
               fallback])

          A convenience method which coerces the 'option' in the
          specified 'section' to a floating-point number.  See *note
          get(): 12b2. for explanation of 'raw', 'vars' and 'fallback'.

      -- Method: getboolean (section, option, *, raw=False, vars=None[,
               fallback])

          A convenience method which coerces the 'option' in the
          specified 'section' to a Boolean value.  Note that the
          accepted values for the option are ‘'1'’, ‘'yes'’, ‘'true'’,
          and ‘'on'’, which cause this method to return ‘True’, and
          ‘'0'’, ‘'no'’, ‘'false'’, and ‘'off'’, which cause it to
          return ‘False’.  These string values are checked in a
          case-insensitive manner.  Any other value will cause it to
          raise *note ValueError: 202.  See *note get(): 12b2. for
          explanation of 'raw', 'vars' and 'fallback'.

      -- Method: items (raw=False, vars=None)

      -- Method: items (section, raw=False, vars=None)

          When 'section' is not given, return a list of 'section_name',
          'section_proxy' pairs, including DEFAULTSECT.

          Otherwise, return a list of 'name', 'value' pairs for the
          options in the given 'section'.  Optional arguments have the
          same meaning as for the *note get(): 12b2. method.

          Changed in version 3.8: Items present in 'vars' no longer
          appear in the result.  The previous behaviour mixed actual
          parser options with variables provided for interpolation.

      -- Method: set (section, option, value)

          If the given section exists, set the given option to the
          specified value; otherwise raise *note NoSectionError: 2c8b.
          'option' and 'value' must be strings; if not, *note TypeError:
          2c3. is raised.

      -- Method: write (fileobject, space_around_delimiters=True)

          Write a representation of the configuration to the specified
          *note file object: 1208, which must be opened in text mode
          (accepting strings).  This representation can be parsed by a
          future *note read(): 14b7. call.  If 'space_around_delimiters'
          is true, delimiters between keys and values are surrounded by
          spaces.

          Note: Comments in the original configuration file are not
          preserved when writing the configuration back.  What is
          considered a comment, depends on the given values for
          'comment_prefix' and 'inline_comment_prefix'.

      -- Method: remove_option (section, option)

          Remove the specified 'option' from the specified 'section'.
          If the section does not exist, raise *note NoSectionError:
          2c8b.  If the option existed to be removed, return *note True:
          c2d.; otherwise return *note False: b4f.

      -- Method: remove_section (section)

          Remove the specified 'section' from the configuration.  If the
          section in fact existed, return ‘True’.  Otherwise return
          ‘False’.

      -- Method: optionxform (option)

          Transforms the option name 'option' as found in an input file
          or as passed in by client code to the form that should be used
          in the internal structures.  The default implementation
          returns a lower-case version of 'option'; subclasses may
          override this or client code can set an attribute of this name
          on instances to affect this behavior.

          You don’t need to subclass the parser to use this method, you
          can also set it on an instance, to a function that takes a
          string argument and returns a string.  Setting it to ‘str’,
          for example, would make option names case sensitive:

               cfgparser = ConfigParser()
               cfgparser.optionxform = str

          Note that when reading configuration files, whitespace around
          the option names is stripped before ‘optionxform()’ is called.

 -- Data: configparser.UNNAMED_SECTION

     A special object representing a section name used to reference the
     unnamed section (see *note Unnamed Sections: 2c7a.).

 -- Data: configparser.MAX_INTERPOLATION_DEPTH

     The maximum depth for recursive interpolation for *note get():
     12b2. when the 'raw' parameter is false.  This is relevant only
     when the default 'interpolation' is used.


File: python.info,  Node: RawConfigParser Objects,  Next: Exceptions<8>,  Prev: ConfigParser Objects,  Up: configparser — Configuration file parser

5.14.2.11 RawConfigParser Objects
.................................

 -- Class: configparser.RawConfigParser (defaults=None, dict_type=dict,
          allow_no_value=False, *, delimiters=('=', ':'),
          comment_prefixes=('#', ';'), inline_comment_prefixes=None,
          strict=True, empty_lines_in_values=True,
          default_section=configparser.DEFAULTSECT,
          interpolation=BasicInterpolation(), converters={},
          allow_unnamed_section=False)

     Legacy variant of the *note ConfigParser: 1c8.  It has
     interpolation disabled by default and allows for non-string section
     names, option names, and values via its unsafe ‘add_section’ and
     ‘set’ methods, as well as the legacy ‘defaults=’ keyword argument
     handling.

     Changed in version 3.2: 'allow_no_value', 'delimiters',
     'comment_prefixes', 'strict', 'empty_lines_in_values',
     'default_section' and 'interpolation' were added.

     Changed in version 3.5: The 'converters' argument was added.

     Changed in version 3.8: The default 'dict_type' is *note dict: 256,
     since it now preserves insertion order.

     Changed in version 3.13: The 'allow_unnamed_section' argument was
     added.

          Note: Consider using *note ConfigParser: 1c8. instead which
          checks types of the values to be stored internally.  If you
          don’t want interpolation, you can use
          ‘ConfigParser(interpolation=None)’.

      -- Method: add_section (section)

          Add a section named 'section' to the instance.  If a section
          by the given name already exists, *note DuplicateSectionError:
          12b5. is raised.  If the 'default section' name is passed,
          *note ValueError: 202. is raised.

          Type of 'section' is not checked which lets users create
          non-string named sections.  This behaviour is unsupported and
          may cause internal errors.

      -- Method: set (section, option, value)

          If the given section exists, set the given option to the
          specified value; otherwise raise *note NoSectionError: 2c8b.
          While it is possible to use ‘RawConfigParser’ (or *note
          ConfigParser: 1c8. with 'raw' parameters set to true) for
          'internal' storage of non-string values, full functionality
          (including interpolation and output to files) can only be
          achieved using string values.

          This method lets users assign non-string values to keys
          internally.  This behaviour is unsupported and will cause
          errors when attempting to write to a file or get it in non-raw
          mode.  'Use the mapping protocol API' which does not allow
          such assignments to take place.


File: python.info,  Node: Exceptions<8>,  Prev: RawConfigParser Objects,  Up: configparser — Configuration file parser

5.14.2.12 Exceptions
....................

 -- Exception: configparser.Error

     Base class for all other ‘configparser’ exceptions.

 -- Exception: configparser.NoSectionError

     Exception raised when a specified section is not found.

 -- Exception: configparser.DuplicateSectionError

     Exception raised if *note add_section(): 12b4. is called with the
     name of a section that is already present or in strict parsers when
     a section if found more than once in a single input file, string or
     dictionary.

     Changed in version 3.2: Added the optional 'source' and 'lineno'
     attributes and parameters to ‘__init__()’.

 -- Exception: configparser.DuplicateOptionError

     Exception raised by strict parsers if a single option appears twice
     during reading from a single file, string or dictionary.  This
     catches misspellings and case sensitivity-related errors, e.g.  a
     dictionary may have two keys representing the same case-insensitive
     configuration key.

 -- Exception: configparser.NoOptionError

     Exception raised when a specified option is not found in the
     specified section.

 -- Exception: configparser.InterpolationError

     Base class for exceptions raised when problems occur performing
     string interpolation.

 -- Exception: configparser.InterpolationDepthError

     Exception raised when string interpolation cannot be completed
     because the number of iterations exceeds *note
     MAX_INTERPOLATION_DEPTH: 2c8e.  Subclass of *note
     InterpolationError: 2c96.

 -- Exception: configparser.InterpolationMissingOptionError

     Exception raised when an option referenced from a value does not
     exist.  Subclass of *note InterpolationError: 2c96.

 -- Exception: configparser.InterpolationSyntaxError

     Exception raised when the source text into which substitutions are
     made does not conform to the required syntax.  Subclass of *note
     InterpolationError: 2c96.

 -- Exception: configparser.MissingSectionHeaderError

     Exception raised when attempting to parse a file which has no
     section headers.

 -- Exception: configparser.ParsingError

     Exception raised when errors occur attempting to parse a file.

     Changed in version 3.12: The ‘filename’ attribute and ‘__init__()’
     constructor argument were removed.  They have been available using
     the name ‘source’ since 3.2.

 -- Exception: configparser.MultilineContinuationError

     Exception raised when a key without a corresponding value is
     continued with an indented line.

     Added in version 3.13.


File: python.info,  Node: tomllib — Parse TOML files,  Next: netrc — netrc file processing,  Prev: configparser — Configuration file parser,  Up: File Formats

5.14.3 ‘tomllib’ — Parse TOML files
-----------------------------------

Added in version 3.11.

'Source code:' Lib/tomllib(1)

__________________________________________________________________

This module provides an interface for parsing TOML 1.0.0 (Tom’s Obvious
Minimal Language, https://toml.io(2)).  This module does not support
writing TOML.

See also
........

The Tomli-W package(3) is a TOML writer that can be used in conjunction
with this module, providing a write API familiar to users of the
standard library *note marshal: 8d. and *note pickle: a6. modules.

See also
........

The TOML Kit package(4) is a style-preserving TOML library with both
read and write capability.  It is a recommended replacement for this
module for editing already existing TOML files.

This module defines the following functions:

 -- Function: tomllib.load (fp, /, *, parse_float=float)

     Read a TOML file.  The first argument should be a readable and
     binary file object.  Return a *note dict: 256.  Convert TOML types
     to Python using this *note conversion table: 2c9f.

     'parse_float' will be called with the string of every TOML float to
     be decoded.  By default, this is equivalent to ‘float(num_str)’.
     This can be used to use another datatype or parser for TOML floats
     (e.g.  *note decimal.Decimal: 29d.).  The callable must not return
     a *note dict: 256. or a *note list: 614, else a *note ValueError:
     202. is raised.

     A *note TOMLDecodeError: 2ca0. will be raised on an invalid TOML
     document.

 -- Function: tomllib.loads (s, /, *, parse_float=float)

     Load TOML from a *note str: 44f. object.  Return a *note dict: 256.
     Convert TOML types to Python using this *note conversion table:
     2c9f.  The 'parse_float' argument has the same meaning as in *note
     load(): 2c9e.

     A *note TOMLDecodeError: 2ca0. will be raised on an invalid TOML
     document.

The following exceptions are available:

 -- Exception: tomllib.TOMLDecodeError

     Subclass of *note ValueError: 202.

* Menu:

* Examples: Examples<11>.
* Conversion Table::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tomllib

   (2) https://toml.io/en/

   (3) https://pypi.org/project/tomli-w/

   (4) https://pypi.org/project/tomlkit/


File: python.info,  Node: Examples<11>,  Next: Conversion Table,  Up: tomllib — Parse TOML files

5.14.3.1 Examples
.................

Parsing a TOML file:

     import tomllib

     with open("pyproject.toml", "rb") as f:
         data = tomllib.load(f)

Parsing a TOML string:

     import tomllib

     toml_str = """
     python-version = "3.11.0"
     python-implementation = "CPython"
     """

     data = tomllib.loads(toml_str)


File: python.info,  Node: Conversion Table,  Prev: Examples<11>,  Up: tomllib — Parse TOML files

5.14.3.2 Conversion Table
.........................

TOML                   Python
                       
------------------------------------------------------------------------------------------------------------------
                       
TOML document          dict
                       
                       
string                 str
                       
                       
integer                int
                       
                       
float                  float (configurable with 'parse_float')
                       
                       
boolean                bool
                       
                       
offset date-time       datetime.datetime (‘tzinfo’ attribute set to an instance of ‘datetime.timezone’)
                       
                       
local date-time        datetime.datetime (‘tzinfo’ attribute set to ‘None’)
                       
                       
local date             datetime.date
                       
                       
local time             datetime.time
                       
                       
array                  list
                       
                       
table                  dict
                       
                       
inline table           dict
                       
                       
array of tables        list of dicts
                       


File: python.info,  Node: netrc — netrc file processing,  Next: plistlib — Generate and parse Apple plist files,  Prev: tomllib — Parse TOML files,  Up: File Formats

5.14.4 ‘netrc’ — netrc file processing
--------------------------------------

'Source code:' Lib/netrc.py(1)

__________________________________________________________________

The *note netrc: 1a20. class parses and encapsulates the netrc file
format used by the Unix ‘ftp’ program and other FTP clients.

 -- Class: netrc.netrc ([file])

     A *note netrc: 1a20. instance or subclass instance encapsulates
     data from a netrc file.  The initialization argument, if present,
     specifies the file to parse.  If no argument is given, the file
     ‘.netrc’ in the user’s home directory – as determined by *note
     os.path.expanduser(): a21. – will be read.  Otherwise, a *note
     FileNotFoundError: 42e. exception will be raised.  Parse errors
     will raise *note NetrcParseError: 2ca7. with diagnostic information
     including the file name, line number, and terminating token.

     If no argument is specified on a POSIX system, the presence of
     passwords in the ‘.netrc’ file will raise a *note NetrcParseError:
     2ca7. if the file ownership or permissions are insecure (owned by a
     user other than the user running the process, or accessible for
     read or write by any other user).  This implements security
     behavior equivalent to that of ftp and other programs that use
     ‘.netrc’.  Such security checks are not available on platforms that
     do not support *note os.getuid(): 1632.

     Changed in version 3.4: Added the POSIX permission check.

     Changed in version 3.7: *note os.path.expanduser(): a21. is used to
     find the location of the ‘.netrc’ file when 'file' is not passed as
     argument.

     Changed in version 3.10: ‘netrc’ try UTF-8 encoding before using
     locale specific encoding.  The entry in the netrc file no longer
     needs to contain all tokens.  The missing tokens’ value default to
     an empty string.  All the tokens and their values now can contain
     arbitrary characters, like whitespace and non-ASCII characters.  If
     the login name is anonymous, it won’t trigger the security check.

 -- Exception: netrc.NetrcParseError

     Exception raised by the *note netrc: 1a20. class when syntactical
     errors are encountered in source text.  Instances of this exception
     provide three interesting attributes:

      -- Attribute: msg

          Textual explanation of the error.

      -- Attribute: filename

          The name of the source file.

      -- Attribute: lineno

          The line number on which the error was found.

* Menu:

* netrc Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/netrc.py


File: python.info,  Node: netrc Objects,  Up: netrc — netrc file processing

5.14.4.1 netrc Objects
......................

A *note netrc: 1a20. instance has the following methods:

 -- Method: netrc.authenticators (host)

     Return a 3-tuple ‘(login, account, password)’ of authenticators for
     'host'.  If the netrc file did not contain an entry for the given
     host, return the tuple associated with the ‘default’ entry.  If
     neither matching host nor default entry is available, return
     ‘None’.

 -- Method: netrc.__repr__ ()

     Dump the class data as a string in the format of a netrc file.
     (This discards comments and may reorder the entries.)

Instances of *note netrc: 1a20. have public instance variables:

 -- Attribute: netrc.hosts

     Dictionary mapping host names to ‘(login, account, password)’
     tuples.  The ‘default’ entry, if any, is represented as a
     pseudo-host by that name.

 -- Attribute: netrc.macros

     Dictionary mapping macro names to string lists.


File: python.info,  Node: plistlib — Generate and parse Apple plist files,  Prev: netrc — netrc file processing,  Up: File Formats

5.14.5 ‘plistlib’ — Generate and parse Apple ‘.plist’ files
-----------------------------------------------------------

'Source code:' Lib/plistlib.py(1)

__________________________________________________________________

This module provides an interface for reading and writing the “property
list” files used by Apple, primarily on macOS and iOS. This module
supports both binary and XML plist files.

The property list (‘.plist’) file format is a simple serialization
supporting basic object types, like dictionaries, lists, numbers and
strings.  Usually the top level object is a dictionary.

To write out and to parse a plist file, use the *note dump(): 95b. and
*note load(): 959. functions.

To work with plist data in bytes or string objects, use *note dumps():
95c. and *note loads(): 95a.

Values can be strings, integers, floats, booleans, tuples, lists,
dictionaries (but only with string keys), *note bytes: 1c2, *note
bytearray: 2ea. or *note datetime.datetime: 1cc. objects.

Changed in version 3.4: New API, old API deprecated.  Support for binary
format plists added.

Changed in version 3.8: Support added for reading and writing *note UID:
a2e. tokens in binary plists as used by NSKeyedArchiver and
NSKeyedUnarchiver.

Changed in version 3.9: Old API removed.

See also
........

PList manual page(2)

     Apple’s documentation of the file format.

This module defines the following functions:

 -- Function: plistlib.load (fp, *, fmt=None, dict_type=dict,
          aware_datetime=False)

     Read a plist file.  'fp' should be a readable and binary file
     object.  Return the unpacked root object (which usually is a
     dictionary).

     The 'fmt' is the format of the file and the following values are
     valid:

        * *note None: 678.: Autodetect the file format

        * *note FMT_XML: fb2.: XML file format

        * *note FMT_BINARY: fb3.: Binary plist format

     The 'dict_type' is the type used for dictionaries that are read
     from the plist file.

     When 'aware_datetime' is true, fields with type ‘datetime.datetime’
     will be created as *note aware object: 25e6, with ‘tzinfo’ as *note
     datetime.UTC: 4f1.

     XML data for the *note FMT_XML: fb2. format is parsed using the
     Expat parser from *note xml.parsers.expat: 126. – see its
     documentation for possible exceptions on ill-formed XML. Unknown
     elements will simply be ignored by the plist parser.

     The parser raises *note InvalidFileException: 1aa1. when the file
     cannot be parsed.

     Added in version 3.4.

     Changed in version 3.13: The keyword-only parameter
     'aware_datetime' has been added.

 -- Function: plistlib.loads (data, *, fmt=None, dict_type=dict,
          aware_datetime=False)

     Load a plist from a bytes or string object.  See *note load(): 959.
     for an explanation of the keyword arguments.

     Added in version 3.4.

     Changed in version 3.13: 'data' can be a string when 'fmt' equals
     *note FMT_XML: fb2.

 -- Function: plistlib.dump (value, fp, *, fmt=FMT_XML, sort_keys=True,
          skipkeys=False, aware_datetime=False)

     Write 'value' to a plist file.  'fp' should be a writable, binary
     file object.

     The 'fmt' argument specifies the format of the plist file and can
     be one of the following values:

        * *note FMT_XML: fb2.: XML formatted plist file

        * *note FMT_BINARY: fb3.: Binary formatted plist file

     When 'sort_keys' is true (the default) the keys for dictionaries
     will be written to the plist in sorted order, otherwise they will
     be written in the iteration order of the dictionary.

     When 'skipkeys' is false (the default) the function raises *note
     TypeError: 2c3. when a key of a dictionary is not a string,
     otherwise such keys are skipped.

     When 'aware_datetime' is true and any field with type
     ‘datetime.datetime’ is set as an *note aware object: 25e6, it will
     convert to UTC timezone before writing it.

     A *note TypeError: 2c3. will be raised if the object is of an
     unsupported type or a container that contains objects of
     unsupported types.

     An *note OverflowError: 888. will be raised for integer values that
     cannot be represented in (binary) plist files.

     Added in version 3.4.

     Changed in version 3.13: The keyword-only parameter
     'aware_datetime' has been added.

 -- Function: plistlib.dumps (value, *, fmt=FMT_XML, sort_keys=True,
          skipkeys=False, aware_datetime=False)

     Return 'value' as a plist-formatted bytes object.  See the
     documentation for *note dump(): 95b. for an explanation of the
     keyword arguments of this function.

     Added in version 3.4.

The following classes are available:

 -- Class: plistlib.UID (data)

     Wraps an *note int: 257.  This is used when reading or writing
     NSKeyedArchiver encoded data, which contains UID (see PList
     manual).

      -- Attribute: data

          Int value of the UID. It must be in the range ‘0 <= data <
          2**64’.

     Added in version 3.8.

The following constants are available:

 -- Data: plistlib.FMT_XML

     The XML format for plist files.

     Added in version 3.4.

 -- Data: plistlib.FMT_BINARY

     The binary format for plist files

     Added in version 3.4.

The module defines the following exceptions:

 -- Exception: plistlib.InvalidFileException

     Raised when a file cannot be parsed.

     Added in version 3.4.

* Menu:

* Examples: Examples<12>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/plistlib.py

   (2) 
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/PropertyLists/


File: python.info,  Node: Examples<12>,  Up: plistlib — Generate and parse Apple plist files

5.14.5.1 Examples
.................

Generating a plist:

     import datetime as dt
     import plistlib

     pl = dict(
         aString = "Doodah",
         aList = ["A", "B", 12, 32.1, [1, 2, 3]],
         aFloat = 0.1,
         anInt = 728,
         aDict = dict(
             anotherString = "<hello & hi there!>",
             aThirdString = "M\xe4ssig, Ma\xdf",
             aTrueValue = True,
             aFalseValue = False,
         ),
         someData = b"<binary gunk>",
         someMoreData = b"<lots of binary gunk>" * 10,
         aDate = dt.datetime.now()
     )
     print(plistlib.dumps(pl).decode())

Parsing a plist:

     import plistlib

     plist = b"""<plist version="1.0">
     <dict>
         <key>foo</key>
         <string>bar</string>
     </dict>
     </plist>"""
     pl = plistlib.loads(plist)
     print(pl["foo"])


File: python.info,  Node: Cryptographic Services,  Next: Generic Operating System Services,  Prev: File Formats,  Up: The Python Standard Library

5.15 Cryptographic Services
===========================

The modules described in this chapter implement various algorithms of a
cryptographic nature.  They are available at the discretion of the
installation.  Here’s an overview:

* Menu:

* hashlib — Secure hashes and message digests::
* hmac — Keyed-Hashing for Message Authentication::
* secrets — Generate secure random numbers for managing secrets::


File: python.info,  Node: hashlib — Secure hashes and message digests,  Next: hmac — Keyed-Hashing for Message Authentication,  Up: Cryptographic Services

5.15.1 ‘hashlib’ — Secure hashes and message digests
----------------------------------------------------

'Source code:' Lib/hashlib.py(1)

__________________________________________________________________

This module implements a common interface to many different hash
algorithms.  Included are the FIPS secure hash algorithms SHA224,
SHA256, SHA384, SHA512, (defined in the FIPS 180-4 standard(2)), the
SHA-3 series (defined in the FIPS 202 standard(3)) as well as the legacy
algorithms SHA1 (formerly part of FIPS(4)) and the MD5 algorithm
(defined in internet RFC 1321(5)).

     Note: If you want the adler32 or crc32 hash functions, they are
     available in the *note zlib: 133. module.

* Menu:

* Hash algorithms::
* Usage::
* Constructors::
* Attributes::
* Hash Objects::
* SHAKE variable length digests::
* File hashing::
* Key derivation::
* BLAKE2::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/hashlib.py

   (2) https://csrc.nist.gov/pubs/fips/180-4/upd1/final

   (3) https://csrc.nist.gov/pubs/fips/202/final

   (4) https://csrc.nist.gov/news/2023/decision-to-revise-fips-180-4

   (5) https://datatracker.ietf.org/doc/html/rfc1321.html


File: python.info,  Node: Hash algorithms,  Next: Usage,  Up: hashlib — Secure hashes and message digests

5.15.1.1 Hash algorithms
........................

There is one constructor method named for each type of 'hash'.  All
return a hash object with the same simple interface.  For example: use
*note sha256(): 1669. to create a SHA-256 hash object.  You can now feed
this object with *note bytes-like objects: d55. (normally *note bytes:
1c2.) using the *note update: 2cbe. method.  At any point you can ask it
for the 'digest' of the concatenation of the data fed to it so far using
the *note digest(): 2cbf. or *note hexdigest(): 2cc0. methods.

To allow multithreading, the Python *note GIL: 159. is released while
computing a hash supplied more than 2047 bytes of data at once in its
constructor or *note .update: 2cbe. method.

Constructors for hash algorithms that are always present in this module
are *note sha1(): 2cc1, *note sha224(): 2cc2, *note sha256(): 1669,
*note sha384(): 2cc3, *note sha512(): 2cc4, *note sha3_224(): cc8, *note
sha3_256(): cc9, *note sha3_384(): cca, *note sha3_512(): ccb, *note
shake_128(): ccc, *note shake_256(): ccd, *note blake2b(): 645, and
*note blake2s(): 646.  *note md5(): 1646. is normally available as well,
though it may be missing or blocked if you are using a rare “FIPS
compliant” build of Python.  These correspond to *note
algorithms_guaranteed: 13c0.

Additional algorithms may also be available if your Python
distribution’s ‘hashlib’ was linked against a build of OpenSSL that
provides others.  Others 'are not guaranteed available' on all
installations and will only be accessible by name via *note new(): 1ad5.
See *note algorithms_available: 13c1.

     Warning: Some algorithms have known hash collision weaknesses
     (including MD5 and SHA1).  Refer to Attacks on cryptographic hash
     algorithms(1) and the *note hashlib-seealso: 2cc5. section at the
     end of this document.

Added in version 3.6: SHA3 (Keccak) and SHAKE constructors *note
sha3_224(): cc8, *note sha3_256(): cc9, *note sha3_384(): cca, *note
sha3_512(): ccb, *note shake_128(): ccc, *note shake_256(): ccd. were
added.  *note blake2b(): 645. and *note blake2s(): 646. were added.

Changed in version 3.9: All hashlib constructors take a keyword-only
argument 'usedforsecurity' with default value ‘True’.  A false value
allows the use of insecure and blocked hashing algorithms in restricted
environments.  ‘False’ indicates that the hashing algorithm is not used
in a security context, e.g.  as a non-cryptographic one-way compression
function.

Changed in version 3.9: Hashlib now uses SHA3 and SHAKE from OpenSSL if
it provides it.

Changed in version 3.12: For any of the MD5, SHA1, SHA2, or SHA3
algorithms that the linked OpenSSL does not provide we fall back to a
verified implementation from the HACL* project(2).

   ---------- Footnotes ----------

   (1) 
https://en.wikipedia.org/wiki/Cryptographic_hash_function#Attacks_on_cryptographic_hash_algorithms

   (2) https://github.com/hacl-star/hacl-star


File: python.info,  Node: Usage,  Next: Constructors,  Prev: Hash algorithms,  Up: hashlib — Secure hashes and message digests

5.15.1.2 Usage
..............

To obtain the digest of the byte string ‘b"Nobody inspects the spammish
repetition"’:

     >>> import hashlib
     >>> m = hashlib.sha256()
     >>> m.update(b"Nobody inspects")
     >>> m.update(b" the spammish repetition")
     >>> m.digest()
     b'\x03\x1e\xdd}Ae\x15\x93\xc5\xfe\\\x00o\xa5u+7\xfd\xdf\xf7\xbcN\x84:\xa6\xaf\x0c\x95\x0fK\x94\x06'
     >>> m.hexdigest()
     '031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'

More condensed:

     >>> hashlib.sha256(b"Nobody inspects the spammish repetition").hexdigest()
     '031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'


File: python.info,  Node: Constructors,  Next: Attributes,  Prev: Usage,  Up: hashlib — Secure hashes and message digests

5.15.1.3 Constructors
.....................

 -- Function: hashlib.new (name[, data], *, usedforsecurity=True)

     Is a generic constructor that takes the string 'name' of the
     desired algorithm as its first parameter.  It also exists to allow
     access to the above listed hashes as well as any other algorithms
     that your OpenSSL library may offer.

Using *note new(): 1ad5. with an algorithm name:

     >>> h = hashlib.new('sha256')
     >>> h.update(b"Nobody inspects the spammish repetition")
     >>> h.hexdigest()
     '031edd7d41651593c5fe5c006fa5752b37fddff7bc4e843aa6af0c950f4b9406'

 -- Function: hashlib.md5 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha1 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha224 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha256 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha384 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha512 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha3_224 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha3_256 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha3_384 ([data], *, usedforsecurity=True)

 -- Function: hashlib.sha3_512 ([data], *, usedforsecurity=True)

Named constructors such as these are faster than passing an algorithm
name to *note new(): 1ad5.


File: python.info,  Node: Attributes,  Next: Hash Objects,  Prev: Constructors,  Up: hashlib — Secure hashes and message digests

5.15.1.4 Attributes
...................

Hashlib provides the following constant module attributes:

 -- Data: hashlib.algorithms_guaranteed

     A set containing the names of the hash algorithms guaranteed to be
     supported by this module on all platforms.  Note that ‘md5’ is in
     this list despite some upstream vendors offering an odd “FIPS
     compliant” Python build that excludes it.

     Added in version 3.2.

 -- Data: hashlib.algorithms_available

     A set containing the names of the hash algorithms that are
     available in the running Python interpreter.  These names will be
     recognized when passed to *note new(): 1ad5.  *note
     algorithms_guaranteed: 13c0. will always be a subset.  The same
     algorithm may appear multiple times in this set under different
     names (thanks to OpenSSL).

     Added in version 3.2.


File: python.info,  Node: Hash Objects,  Next: SHAKE variable length digests,  Prev: Attributes,  Up: hashlib — Secure hashes and message digests

5.15.1.5 Hash Objects
.....................

The following values are provided as constant attributes of the hash
objects returned by the constructors:

 -- Data: hash.digest_size

     The size of the resulting hash in bytes.

 -- Data: hash.block_size

     The internal block size of the hash algorithm in bytes.

A hash object has the following attributes:

 -- Attribute: hash.name

     The canonical name of this hash, always lowercase and always
     suitable as a parameter to *note new(): 1ad5. to create another
     hash of this type.

     Changed in version 3.4: The name attribute has been present in
     CPython since its inception, but until Python 3.4 was not formally
     specified, so may not exist on some platforms.

A hash object has the following methods:

 -- Method: hash.update (data)

     Update the hash object with the *note bytes-like object: d55.
     Repeated calls are equivalent to a single call with the
     concatenation of all the arguments: ‘m.update(a); m.update(b)’ is
     equivalent to ‘m.update(a+b)’.

 -- Method: hash.digest ()

     Return the digest of the data passed to the *note update(): 2cbe.
     method so far.  This is a bytes object of size *note digest_size:
     2ccb. which may contain bytes in the whole range from 0 to 255.

 -- Method: hash.hexdigest ()

     Like *note digest(): 2cbf. except the digest is returned as a
     string object of double length, containing only hexadecimal digits.
     This may be used to exchange the value safely in email or other
     non-binary environments.

 -- Method: hash.copy ()

     Return a copy (“clone”) of the hash object.  This can be used to
     efficiently compute the digests of data sharing a common initial
     substring.


File: python.info,  Node: SHAKE variable length digests,  Next: File hashing,  Prev: Hash Objects,  Up: hashlib — Secure hashes and message digests

5.15.1.6 SHAKE variable length digests
......................................

 -- Function: hashlib.shake_128 ([data], *, usedforsecurity=True)

 -- Function: hashlib.shake_256 ([data], *, usedforsecurity=True)

The *note shake_128(): ccc. and *note shake_256(): ccd. algorithms
provide variable length digests with length_in_bits//2 up to 128 or 256
bits of security.  As such, their digest methods require a length.
Maximum length is not limited by the SHAKE algorithm.

 -- Method: shake.digest (length)

     Return the digest of the data passed to the *note update(): 2cbe.
     method so far.  This is a bytes object of size 'length' which may
     contain bytes in the whole range from 0 to 255.

 -- Method: shake.hexdigest (length)

     Like *note digest(): 1bc9. except the digest is returned as a
     string object of double length, containing only hexadecimal digits.
     This may be used to exchange the value in email or other non-binary
     environments.

Example use:

     >>> h = hashlib.shake_256(b'Nobody inspects the spammish repetition')
     >>> h.hexdigest(20)
     '44709d6fcb83d92a76dcb0b668c98e1b1d3dafe7'


File: python.info,  Node: File hashing,  Next: Key derivation,  Prev: SHAKE variable length digests,  Up: hashlib — Secure hashes and message digests

5.15.1.7 File hashing
.....................

The hashlib module provides a helper function for efficient hashing of a
file or file-like object.

 -- Function: hashlib.file_digest (fileobj, digest, /)

     Return a digest object that has been updated with contents of file
     object.

     'fileobj' must be a file-like object opened for reading in binary
     mode.  It accepts file objects from builtin *note open(): 51f,
     *note BytesIO: ed8. instances, SocketIO objects from *note
     socket.socket.makefile(): 11e3, and similar.  'fileobj' must be
     opened in blocking mode, otherwise a *note BlockingIOError: 1095.
     may be raised.

     The function may bypass Python’s I/O and use the file descriptor
     from *note fileno(): 15f5. directly.  'fileobj' must be assumed to
     be in an unknown state after this function returns or raises.  It
     is up to the caller to close 'fileobj'.

     'digest' must either be a hash algorithm name as a 'str', a hash
     constructor, or a callable that returns a hash object.

     Example:

          >>> import io, hashlib, hmac
          >>> with open("library/hashlib.rst", "rb") as f:
          ...     digest = hashlib.file_digest(f, "sha256")
          ...
          >>> digest.hexdigest()
          '...'

          >>> buf = io.BytesIO(b"somedata")
          >>> mac1 = hmac.HMAC(b"key", digestmod=hashlib.sha512)
          >>> digest = hashlib.file_digest(buf, lambda: mac1)

          >>> digest is mac1
          True
          >>> mac2 = hmac.HMAC(b"key", b"somedata", digestmod=hashlib.sha512)
          >>> mac1.digest() == mac2.digest()
          True

     Added in version 3.11.

     Changed in version 3.13.4: Now raises a *note BlockingIOError:
     1095. if the file is opened in non-blocking mode.  Previously,
     spurious null bytes were added to the digest.


File: python.info,  Node: Key derivation,  Next: BLAKE2,  Prev: File hashing,  Up: hashlib — Secure hashes and message digests

5.15.1.8 Key derivation
.......................

Key derivation and key stretching algorithms are designed for secure
password hashing.  Naive algorithms such as ‘sha1(password)’ are not
resistant against brute-force attacks.  A good password hashing function
must be tunable, slow, and include a salt(1).

 -- Function: hashlib.pbkdf2_hmac (hash_name, password, salt,
          iterations, dklen=None)

     The function provides PKCS#5 password-based key derivation function
     2.  It uses HMAC as pseudorandom function.

     The string 'hash_name' is the desired name of the hash digest
     algorithm for HMAC, e.g.  ‘sha1’ or ‘sha256’.  'password' and
     'salt' are interpreted as buffers of bytes.  Applications and
     libraries should limit 'password' to a sensible length (e.g.
     1024).  'salt' should be about 16 or more bytes from a proper
     source, e.g.  *note os.urandom(): 526.

     The number of 'iterations' should be chosen based on the hash
     algorithm and computing power.  As of 2022, hundreds of thousands
     of iterations of SHA-256 are suggested.  For rationale as to why
     and how to choose what is best for your application, read 'Appendix
     A.2.2' of NIST-SP-800-132(2).  The answers on the stackexchange
     pbkdf2 iterations question(3) explain in detail.

     'dklen' is the length of the derived key in bytes.  If 'dklen' is
     ‘None’ then the digest size of the hash algorithm 'hash_name' is
     used, e.g.  64 for SHA-512.

          >>> from hashlib import pbkdf2_hmac
          >>> our_app_iters = 500_000  # Application specific, read above.
          >>> dk = pbkdf2_hmac('sha256', b'password', b'bad salt' * 2, our_app_iters)
          >>> dk.hex()
          '15530bba69924174860db778f2c6f8104d3aaf9d26241840c8c4a641c8d000a9'

     Function only available when Python is compiled with OpenSSL.

     Added in version 3.4.

     Changed in version 3.12: Function now only available when Python is
     built with OpenSSL. The slow pure Python implementation has been
     removed.

 -- Function: hashlib.scrypt (password, *, salt, n, r, p, maxmem=0,
          dklen=64)

     The function provides scrypt password-based key derivation function
     as defined in RFC 7914(4).

     'password' and 'salt' must be *note bytes-like objects: d55.
     Applications and libraries should limit 'password' to a sensible
     length (e.g.  1024).  'salt' should be about 16 or more bytes from
     a proper source, e.g.  *note os.urandom(): 526.

     'n' is the CPU/Memory cost factor, 'r' the block size, 'p'
     parallelization factor and 'maxmem' limits memory (OpenSSL 1.1.0
     defaults to 32 MiB). 'dklen' is the length of the derived key in
     bytes.

     Added in version 3.6.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Salt_%28cryptography%29

   (2) 
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf

   (3) 
https://security.stackexchange.com/questions/3959/recommended-of-iterations-when-using-pbkdf2-sha256/

   (4) https://datatracker.ietf.org/doc/html/rfc7914.html


File: python.info,  Node: BLAKE2,  Prev: Key derivation,  Up: hashlib — Secure hashes and message digests

5.15.1.9 BLAKE2
...............

BLAKE2(1) is a cryptographic hash function defined in RFC 7693(2) that
comes in two flavors:

   * 'BLAKE2b', optimized for 64-bit platforms and produces digests of
     any size between 1 and 64 bytes,

   * 'BLAKE2s', optimized for 8- to 32-bit platforms and produces
     digests of any size between 1 and 32 bytes.

BLAKE2 supports 'keyed mode' (a faster and simpler replacement for
HMAC(3)), 'salted hashing', 'personalization', and 'tree hashing'.

Hash objects from this module follow the API of standard library’s
‘hashlib’ objects.

* Menu:

* Creating hash objects::
* Constants: Constants<5>.
* Examples: Examples<13>.
* Credits::

   ---------- Footnotes ----------

   (1) https://www.blake2.net

   (2) https://datatracker.ietf.org/doc/html/rfc7693.html

   (3) 
https://en.wikipedia.org/wiki/Hash-based_message_authentication_code


File: python.info,  Node: Creating hash objects,  Next: Constants<5>,  Up: BLAKE2

5.15.1.10 Creating hash objects
...............................

New hash objects are created by calling constructor functions:

 -- Function: hashlib.blake2b (data=b'', *, digest_size=64, key=b'',
          salt=b'', person=b'', fanout=1, depth=1, leaf_size=0,
          node_offset=0, node_depth=0, inner_size=0, last_node=False,
          usedforsecurity=True)

 -- Function: hashlib.blake2s (data=b'', *, digest_size=32, key=b'',
          salt=b'', person=b'', fanout=1, depth=1, leaf_size=0,
          node_offset=0, node_depth=0, inner_size=0, last_node=False,
          usedforsecurity=True)

These functions return the corresponding hash objects for calculating
BLAKE2b or BLAKE2s.  They optionally take these general parameters:

   * 'data': initial chunk of data to hash, which must be *note
     bytes-like object: d55.  It can be passed only as positional
     argument.

   * 'digest_size': size of output digest in bytes.

   * 'key': key for keyed hashing (up to 64 bytes for BLAKE2b, up to 32
     bytes for BLAKE2s).

   * 'salt': salt for randomized hashing (up to 16 bytes for BLAKE2b, up
     to 8 bytes for BLAKE2s).

   * 'person': personalization string (up to 16 bytes for BLAKE2b, up to
     8 bytes for BLAKE2s).

The following table shows limits for general parameters (in bytes):

Hash        digest_size     len(key)     len(salt)     len(person)
                                                       
-----------------------------------------------------------------------
                                                       
BLAKE2b     64              64           16            16
                                                       
                                                       
BLAKE2s     32              32           8             8
                                                       

     Note: BLAKE2 specification defines constant lengths for salt and
     personalization parameters, however, for convenience, this
     implementation accepts byte strings of any size up to the specified
     length.  If the length of the parameter is less than specified, it
     is padded with zeros, thus, for example, ‘b'salt'’ and
     ‘b'salt\x00'’ is the same value.  (This is not the case for 'key'.)

These sizes are available as module *note constants: 2cd3. described
below.

Constructor functions also accept the following tree hashing parameters:

   * 'fanout': fanout (0 to 255, 0 if unlimited, 1 in sequential mode).

   * 'depth': maximal depth of tree (1 to 255, 255 if unlimited, 1 in
     sequential mode).

   * 'leaf_size': maximal byte length of leaf (0 to ‘2**32-1’, 0 if
     unlimited or in sequential mode).

   * 'node_offset': node offset (0 to ‘2**64-1’ for BLAKE2b, 0 to
     ‘2**48-1’ for BLAKE2s, 0 for the first, leftmost, leaf, or in
     sequential mode).

   * 'node_depth': node depth (0 to 255, 0 for leaves, or in sequential
     mode).

   * 'inner_size': inner digest size (0 to 64 for BLAKE2b, 0 to 32 for
     BLAKE2s, 0 in sequential mode).

   * 'last_node': boolean indicating whether the processed node is the
     last one (‘False’ for sequential mode).

[image src="python-figures/hashlib-blake2-tree.png" alt="Explanation of tree mode parameters."]


Figure
See section 2.10 in BLAKE2 specification(1) for comprehensive review of
tree hashing.

   ---------- Footnotes ----------

   (1) https://www.blake2.net/blake2_20130129.pdf


File: python.info,  Node: Constants<5>,  Next: Examples<13>,  Prev: Creating hash objects,  Up: BLAKE2

5.15.1.11 Constants
...................

 -- Data: blake2b.SALT_SIZE

 -- Data: blake2s.SALT_SIZE

Salt length (maximum length accepted by constructors).

 -- Data: blake2b.PERSON_SIZE

 -- Data: blake2s.PERSON_SIZE

Personalization string length (maximum length accepted by constructors).

 -- Data: blake2b.MAX_KEY_SIZE

 -- Data: blake2s.MAX_KEY_SIZE

Maximum key size.

 -- Data: blake2b.MAX_DIGEST_SIZE

 -- Data: blake2s.MAX_DIGEST_SIZE

Maximum digest size that the hash function can output.


File: python.info,  Node: Examples<13>,  Next: Credits,  Prev: Constants<5>,  Up: BLAKE2

5.15.1.12 Examples
..................

* Menu:

* Simple hashing::
* Using different digest sizes::
* Keyed hashing::
* Randomized hashing::
* Personalization::
* Tree mode::


File: python.info,  Node: Simple hashing,  Next: Using different digest sizes,  Up: Examples<13>

5.15.1.13 Simple hashing
........................

To calculate hash of some data, you should first construct a hash object
by calling the appropriate constructor function (*note blake2b(): 645.
or *note blake2s(): 646.), then update it with the data by calling *note
update(): 2cbe. on the object, and, finally, get the digest out of the
object by calling *note digest(): 2cbf. (or *note hexdigest(): 2cc0. for
hex-encoded string).

     >>> from hashlib import blake2b
     >>> h = blake2b()
     >>> h.update(b'Hello world')
     >>> h.hexdigest()
     '6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'

As a shortcut, you can pass the first chunk of data to update directly
to the constructor as the positional argument:

     >>> from hashlib import blake2b
     >>> blake2b(b'Hello world').hexdigest()
     '6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'

You can call *note hash.update(): 2cbe. as many times as you need to
iteratively update the hash:

     >>> from hashlib import blake2b
     >>> items = [b'Hello', b' ', b'world']
     >>> h = blake2b()
     >>> for item in items:
     ...     h.update(item)
     ...
     >>> h.hexdigest()
     '6ff843ba685842aa82031d3f53c48b66326df7639a63d128974c5c14f31a0f33343a8c65551134ed1ae0f2b0dd2bb495dc81039e3eeb0aa1bb0388bbeac29183'


File: python.info,  Node: Using different digest sizes,  Next: Keyed hashing,  Prev: Simple hashing,  Up: Examples<13>

5.15.1.14 Using different digest sizes
......................................

BLAKE2 has configurable size of digests up to 64 bytes for BLAKE2b and
up to 32 bytes for BLAKE2s.  For example, to replace SHA-1 with BLAKE2b
without changing the size of output, we can tell BLAKE2b to produce
20-byte digests:

     >>> from hashlib import blake2b
     >>> h = blake2b(digest_size=20)
     >>> h.update(b'Replacing SHA1 with the more secure function')
     >>> h.hexdigest()
     'd24f26cf8de66472d58d4e1b1774b4c9158b1f4c'
     >>> h.digest_size
     20
     >>> len(h.digest())
     20

Hash objects with different digest sizes have completely different
outputs (shorter hashes are 'not' prefixes of longer hashes); BLAKE2b
and BLAKE2s produce different outputs even if the output length is the
same:

     >>> from hashlib import blake2b, blake2s
     >>> blake2b(digest_size=10).hexdigest()
     '6fa1d8fcfd719046d762'
     >>> blake2b(digest_size=11).hexdigest()
     'eb6ec15daf9546254f0809'
     >>> blake2s(digest_size=10).hexdigest()
     '1bf21a98c78a1c376ae9'
     >>> blake2s(digest_size=11).hexdigest()
     '567004bf96e4a25773ebf4'


File: python.info,  Node: Keyed hashing,  Next: Randomized hashing,  Prev: Using different digest sizes,  Up: Examples<13>

5.15.1.15 Keyed hashing
.......................

Keyed hashing can be used for authentication as a faster and simpler
replacement for Hash-based message authentication code(1) (HMAC). BLAKE2
can be securely used in prefix-MAC mode thanks to the
indifferentiability property inherited from BLAKE.

This example shows how to get a (hex-encoded) 128-bit authentication
code for message ‘b'message data'’ with key ‘b'pseudorandom key'’:

     >>> from hashlib import blake2b
     >>> h = blake2b(key=b'pseudorandom key', digest_size=16)
     >>> h.update(b'message data')
     >>> h.hexdigest()
     '3d363ff7401e02026f4a4687d4863ced'

As a practical example, a web application can symmetrically sign cookies
sent to users and later verify them to make sure they weren’t tampered
with:

     >>> from hashlib import blake2b
     >>> from hmac import compare_digest
     >>>
     >>> SECRET_KEY = b'pseudorandomly generated server secret key'
     >>> AUTH_SIZE = 16
     >>>
     >>> def sign(cookie):
     ...     h = blake2b(digest_size=AUTH_SIZE, key=SECRET_KEY)
     ...     h.update(cookie)
     ...     return h.hexdigest().encode('utf-8')
     >>>
     >>> def verify(cookie, sig):
     ...     good_sig = sign(cookie)
     ...     return compare_digest(good_sig, sig)
     >>>
     >>> cookie = b'user-alice'
     >>> sig = sign(cookie)
     >>> print("{0},{1}".format(cookie.decode('utf-8'), sig))
     user-alice,b'43b3c982cf697e0c5ab22172d1ca7421'
     >>> verify(cookie, sig)
     True
     >>> verify(b'user-bob', sig)
     False
     >>> verify(cookie, b'0102030405060708090a0b0c0d0e0f00')
     False

Even though there’s a native keyed hashing mode, BLAKE2 can, of course,
be used in HMAC construction with *note hmac: 6a. module:

     >>> import hmac, hashlib
     >>> m = hmac.new(b'secret key', digestmod=hashlib.blake2s)
     >>> m.update(b'message')
     >>> m.hexdigest()
     'e3c8102868d28b5ff85fc35dda07329970d1a01e273c37481326fe0c861c8142'

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/HMAC


File: python.info,  Node: Randomized hashing,  Next: Personalization,  Prev: Keyed hashing,  Up: Examples<13>

5.15.1.16 Randomized hashing
............................

By setting 'salt' parameter users can introduce randomization to the
hash function.  Randomized hashing is useful for protecting against
collision attacks on the hash function used in digital signatures.

     Randomized hashing is designed for situations where one party, the
     message preparer, generates all or part of a message to be signed
     by a second party, the message signer.  If the message preparer is
     able to find cryptographic hash function collisions (i.e., two
     messages producing the same hash value), then they might prepare
     meaningful versions of the message that would produce the same hash
     value and digital signature, but with different results (e.g.,
     transferring $1,000,000 to an account, rather than $10).
     Cryptographic hash functions have been designed with collision
     resistance as a major goal, but the current concentration on
     attacking cryptographic hash functions may result in a given
     cryptographic hash function providing less collision resistance
     than expected.  Randomized hashing offers the signer additional
     protection by reducing the likelihood that a preparer can generate
     two or more messages that ultimately yield the same hash value
     during the digital signature generation process — even if it is
     practical to find collisions for the hash function.  However, the
     use of randomized hashing may reduce the amount of security
     provided by a digital signature when all portions of the message
     are prepared by the signer.

     (NIST SP-800-106 "Randomized Hashing for Digital Signatures"(1))

In BLAKE2 the salt is processed as a one-time input to the hash function
during initialization, rather than as an input to each compression
function.

     Warning: 'Salted hashing' (or just hashing) with BLAKE2 or any
     other general-purpose cryptographic hash function, such as SHA-256,
     is not suitable for hashing passwords.  See BLAKE2 FAQ(2) for more
     information.

     >>> import os
     >>> from hashlib import blake2b
     >>> msg = b'some message'
     >>> # Calculate the first hash with a random salt.
     >>> salt1 = os.urandom(blake2b.SALT_SIZE)
     >>> h1 = blake2b(salt=salt1)
     >>> h1.update(msg)
     >>> # Calculate the second hash with a different random salt.
     >>> salt2 = os.urandom(blake2b.SALT_SIZE)
     >>> h2 = blake2b(salt=salt2)
     >>> h2.update(msg)
     >>> # The digests are different.
     >>> h1.digest() != h2.digest()
     True

   ---------- Footnotes ----------

   (1) https://csrc.nist.gov/pubs/sp/800/106/final

   (2) https://www.blake2.net/#qa


File: python.info,  Node: Personalization,  Next: Tree mode,  Prev: Randomized hashing,  Up: Examples<13>

5.15.1.17 Personalization
.........................

Sometimes it is useful to force hash function to produce different
digests for the same input for different purposes.  Quoting the authors
of the Skein hash function:

     We recommend that all application designers seriously consider
     doing this; we have seen many protocols where a hash that is
     computed in one part of the protocol can be used in an entirely
     different part because two hash computations were done on similar
     or related data, and the attacker can force the application to make
     the hash inputs the same.  Personalizing each hash function used in
     the protocol summarily stops this type of attack.

     (The Skein Hash Function Family(1), p.  21)

BLAKE2 can be personalized by passing bytes to the 'person' argument:

     >>> from hashlib import blake2b
     >>> FILES_HASH_PERSON = b'MyApp Files Hash'
     >>> BLOCK_HASH_PERSON = b'MyApp Block Hash'
     >>> h = blake2b(digest_size=32, person=FILES_HASH_PERSON)
     >>> h.update(b'the same content')
     >>> h.hexdigest()
     '20d9cd024d4fb086aae819a1432dd2466de12947831b75c5a30cf2676095d3b4'
     >>> h = blake2b(digest_size=32, person=BLOCK_HASH_PERSON)
     >>> h.update(b'the same content')
     >>> h.hexdigest()
     'cf68fb5761b9c44e7878bfb2c4c9aea52264a80b75005e65619778de59f383a3'

Personalization together with the keyed mode can also be used to derive
different keys from a single one.

     >>> from hashlib import blake2s
     >>> from base64 import b64decode, b64encode
     >>> orig_key = b64decode(b'Rm5EPJai72qcK3RGBpW3vPNfZy5OZothY+kHY6h21KM=')
     >>> enc_key = blake2s(key=orig_key, person=b'kEncrypt').digest()
     >>> mac_key = blake2s(key=orig_key, person=b'kMAC').digest()
     >>> print(b64encode(enc_key).decode('utf-8'))
     rbPb15S/Z9t+agffno5wuhB77VbRi6F9Iv2qIxU7WHw=
     >>> print(b64encode(mac_key).decode('utf-8'))
     G9GtHFE1YluXY1zWPlYk1e/nWfu0WSEb0KRcjhDeP/o=

   ---------- Footnotes ----------

   (1) https://www.schneier.com/wp-content/uploads/2016/02/skein.pdf


File: python.info,  Node: Tree mode,  Prev: Personalization,  Up: Examples<13>

5.15.1.18 Tree mode
...................

Here’s an example of hashing a minimal tree with two leaf nodes:

       10
      /  \
     00  01

This example uses 64-byte internal digests, and returns the 32-byte
final digest:

     >>> from hashlib import blake2b
     >>>
     >>> FANOUT = 2
     >>> DEPTH = 2
     >>> LEAF_SIZE = 4096
     >>> INNER_SIZE = 64
     >>>
     >>> buf = bytearray(6000)
     >>>
     >>> # Left leaf
     ... h00 = blake2b(buf[0:LEAF_SIZE], fanout=FANOUT, depth=DEPTH,
     ...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
     ...               node_offset=0, node_depth=0, last_node=False)
     >>> # Right leaf
     ... h01 = blake2b(buf[LEAF_SIZE:], fanout=FANOUT, depth=DEPTH,
     ...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
     ...               node_offset=1, node_depth=0, last_node=True)
     >>> # Root node
     ... h10 = blake2b(digest_size=32, fanout=FANOUT, depth=DEPTH,
     ...               leaf_size=LEAF_SIZE, inner_size=INNER_SIZE,
     ...               node_offset=0, node_depth=1, last_node=True)
     >>> h10.update(h00.digest())
     >>> h10.update(h01.digest())
     >>> h10.hexdigest()
     '3ad2a9b37c6070e374c7a8c508fe20ca86b6ed54e286e93a0318e95e881db5aa'


File: python.info,  Node: Credits,  Prev: Examples<13>,  Up: BLAKE2

5.15.1.19 Credits
.................

BLAKE2(1) was designed by 'Jean-Philippe Aumasson', 'Samuel Neves',
'Zooko Wilcox-O’Hearn', and 'Christian Winnerlein' based on SHA-3(2)
finalist BLAKE(3) created by 'Jean-Philippe Aumasson', 'Luca Henzen',
'Willi Meier', and 'Raphael C.-W. Phan'.

It uses core algorithm from ChaCha(4) cipher designed by 'Daniel J.
Bernstein'.

The stdlib implementation is based on pyblake2(5) module.  It was
written by 'Dmitry Chestnykh' based on C implementation written by
'Samuel Neves'.  The documentation was copied from pyblake2(6) and
written by 'Dmitry Chestnykh'.

The C code was partly rewritten for Python by 'Christian Heimes'.

The following public domain dedication applies for both C hash function
implementation, extension code, and this documentation:

     To the extent possible under law, the author(s) have dedicated all
     copyright and related and neighboring rights to this software to
     the public domain worldwide.  This software is distributed without
     any warranty.

     You should have received a copy of the CC0 Public Domain Dedication
     along with this software.  If not, see
     ‘https://creativecommons.org/publicdomain/zero/1.0/’.

The following people have helped with development or contributed their
changes to the project and the public domain according to the Creative
Commons Public Domain Dedication 1.0 Universal:

   * 'Alexandr Sokolovskiy'

See also
........

Module *note hmac: 6a.

     A module to generate message authentication codes using hashes.

Module *note base64: e.

     Another way to encode binary hashes for non-binary environments.

‘https://nvlpubs.nist.gov/nistpubs/fips/nist.fips.180-4.pdf’

     The FIPS 180-4 publication on Secure Hash Algorithms.

‘https://csrc.nist.gov/pubs/fips/202/final’

     The FIPS 202 publication on the SHA-3 Standard.

‘https://www.blake2.net/’

     Official BLAKE2 website.

‘https://en.wikipedia.org/wiki/Cryptographic_hash_function’

     Wikipedia article with information on which algorithms have known
     issues and what that means regarding their use.

‘https://www.ietf.org/rfc/rfc8018.txt’

     PKCS #5: Password-Based Cryptography Specification Version 2.1

‘https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-132.pdf’

     NIST Recommendation for Password-Based Key Derivation.

   ---------- Footnotes ----------

   (1) https://www.blake2.net

   (2) https://en.wikipedia.org/wiki/Secure_Hash_Algorithms

   (3) 
https://web.archive.org/web/20200918190133/https://131002.net/blake/

   (4) https://cr.yp.to/chacha.html

   (5) https://pythonhosted.org/pyblake2/

   (6) https://pythonhosted.org/pyblake2/


File: python.info,  Node: hmac — Keyed-Hashing for Message Authentication,  Next: secrets — Generate secure random numbers for managing secrets,  Prev: hashlib — Secure hashes and message digests,  Up: Cryptographic Services

5.15.2 ‘hmac’ — Keyed-Hashing for Message Authentication
--------------------------------------------------------

'Source code:' Lib/hmac.py(1)

__________________________________________________________________

This module implements the HMAC algorithm as described by RFC 2104(2).
The interface allows to use any hash function with a 'fixed' digest
size.  In particular, extendable output functions such as SHAKE-128 or
SHAKE-256 cannot be used with HMAC.

 -- Function: hmac.new (key, msg=None, digestmod)

     Return a new hmac object.  'key' is a bytes or bytearray object
     giving the secret key.  If 'msg' is present, the method call
     ‘update(msg)’ is made.  'digestmod' is the digest name, digest
     constructor or module for the HMAC object to use.  It may be any
     name suitable to *note hashlib.new(): 1ad5.  Despite its argument
     position, it is required.

     Changed in version 3.4: Parameter 'key' can be a bytes or bytearray
     object.  Parameter 'msg' can be of any type supported by *note
     hashlib: 68.  Parameter 'digestmod' can be the name of a hash
     algorithm.

     Changed in version 3.8: The 'digestmod' argument is now required.
     Pass it as a keyword argument to avoid awkwardness when you do not
     have an initial 'msg'.

 -- Function: hmac.digest (key, msg, digest)

     Return digest of 'msg' for given secret 'key' and 'digest'.  The
     function is equivalent to ‘HMAC(key, msg, digest).digest()’, but
     uses an optimized C or inline implementation, which is faster for
     messages that fit into memory.  The parameters 'key', 'msg', and
     'digest' have the same meaning as in *note new(): ab4.

     CPython implementation detail, the optimized C implementation is
     only used when 'digest' is a string and name of a digest algorithm,
     which is supported by OpenSSL.

     Added in version 3.7.

 -- Class: hmac.HMAC

     An HMAC object has the following methods:

 -- Method: HMAC.update (msg)

     Update the hmac object with 'msg'.  Repeated calls are equivalent
     to a single call with the concatenation of all the arguments:
     ‘m.update(a); m.update(b)’ is equivalent to ‘m.update(a + b)’.

     Changed in version 3.4: Parameter 'msg' can be of any type
     supported by *note hashlib: 68.

 -- Method: HMAC.digest ()

     Return the digest of the bytes passed to the *note update(): f82.
     method so far.  This bytes object will be the same length as the
     'digest_size' of the digest given to the constructor.  It may
     contain non-ASCII bytes, including NUL bytes.

          Warning: When comparing the output of ‘digest()’ to an
          externally supplied digest during a verification routine, it
          is recommended to use the *note compare_digest(): 110d.
          function instead of the ‘==’ operator to reduce the
          vulnerability to timing attacks.

 -- Method: HMAC.hexdigest ()

     Like *note digest(): b56. except the digest is returned as a string
     twice the length containing only hexadecimal digits.  This may be
     used to exchange the value safely in email or other non-binary
     environments.

          Warning: When comparing the output of ‘hexdigest()’ to an
          externally supplied digest during a verification routine, it
          is recommended to use the *note compare_digest(): 110d.
          function instead of the ‘==’ operator to reduce the
          vulnerability to timing attacks.

 -- Method: HMAC.copy ()

     Return a copy (“clone”) of the hmac object.  This can be used to
     efficiently compute the digests of strings that share a common
     initial substring.

A hash object has the following attributes:

 -- Attribute: HMAC.digest_size

     The size of the resulting HMAC digest in bytes.

 -- Attribute: HMAC.block_size

     The internal block size of the hash algorithm in bytes.

     Added in version 3.4.

 -- Attribute: HMAC.name

     The canonical name of this HMAC, always lowercase, e.g.
     ‘hmac-md5’.

     Added in version 3.4.

Changed in version 3.10: Removed the undocumented attributes
‘HMAC.digest_cons’, ‘HMAC.inner’, and ‘HMAC.outer’.

This module also provides the following helper function:

 -- Function: hmac.compare_digest (a, b)

     Return ‘a == b’.  This function uses an approach designed to
     prevent timing analysis by avoiding content-based short circuiting
     behaviour, making it appropriate for cryptography.  'a' and 'b'
     must both be of the same type: either *note str: 44f. (ASCII only,
     as e.g.  returned by *note HMAC.hexdigest(): 2ce8.), or a *note
     bytes-like object: d55.

          Note: If 'a' and 'b' are of different lengths, or if an error
          occurs, a timing attack could theoretically reveal information
          about the types and lengths of 'a' and 'b'—but not their
          values.

     Added in version 3.3.

     Changed in version 3.10: The function uses OpenSSL’s
     ‘CRYPTO_memcmp()’ internally when available.

See also
........

Module *note hashlib: 68.

     The Python module providing secure hash functions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/hmac.py

   (2) https://datatracker.ietf.org/doc/html/rfc2104.html


File: python.info,  Node: secrets — Generate secure random numbers for managing secrets,  Prev: hmac — Keyed-Hashing for Message Authentication,  Up: Cryptographic Services

5.15.3 ‘secrets’ — Generate secure random numbers for managing secrets
----------------------------------------------------------------------

Added in version 3.6.

'Source code:' Lib/secrets.py(1)

__________________________________________________________________

The ‘secrets’ module is used for generating cryptographically strong
random numbers suitable for managing data such as passwords, account
authentication, security tokens, and related secrets.

In particular, ‘secrets’ should be used in preference to the default
pseudo-random number generator in the *note random: b8. module, which is
designed for modelling and simulation, not security or cryptography.

See also
........

PEP 506(2)

* Menu:

* Random numbers::
* Generating tokens::
* Other functions::
* Recipes and best practices::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/secrets.py

   (2) https://peps.python.org/pep-0506/


File: python.info,  Node: Random numbers,  Next: Generating tokens,  Up: secrets — Generate secure random numbers for managing secrets

5.15.3.1 Random numbers
.......................

The ‘secrets’ module provides access to the most secure source of
randomness that your operating system provides.

 -- Class: secrets.SystemRandom

     A class for generating random numbers using the highest-quality
     sources provided by the operating system.  See *note
     random.SystemRandom: 28aa. for additional details.

 -- Function: secrets.choice (seq)

     Return a randomly chosen element from a non-empty sequence.

 -- Function: secrets.randbelow (exclusive_upper_bound)

     Return a random int in the range [0, 'exclusive_upper_bound').

 -- Function: secrets.randbits (k)

     Return a non-negative int with 'k' random bits.


File: python.info,  Node: Generating tokens,  Next: Other functions,  Prev: Random numbers,  Up: secrets — Generate secure random numbers for managing secrets

5.15.3.2 Generating tokens
..........................

The ‘secrets’ module provides functions for generating secure tokens,
suitable for applications such as password resets, hard-to-guess URLs,
and similar.

 -- Function: secrets.token_bytes (nbytes=None)

     Return a random byte string containing 'nbytes' number of bytes.

     If 'nbytes' is not specified or ‘None’, *note DEFAULT_ENTROPY:
     2cf2. is used instead.

          >>> token_bytes(16)
          b'\xebr\x17D*t\xae\xd4\xe3S\xb6\xe2\xebP1\x8b'

 -- Function: secrets.token_hex (nbytes=None)

     Return a random text string, in hexadecimal.  The string has
     'nbytes' random bytes, each byte converted to two hex digits.

     If 'nbytes' is not specified or ‘None’, *note DEFAULT_ENTROPY:
     2cf2. is used instead.

          >>> token_hex(16)
          'f9bf78b9a18ce6d46a0cd2b0b86df9da'

 -- Function: secrets.token_urlsafe (nbytes=None)

     Return a random URL-safe text string, containing 'nbytes' random
     bytes.  The text is Base64 encoded, so on average each byte results
     in approximately 1.3 characters.

     If 'nbytes' is not specified or ‘None’, *note DEFAULT_ENTROPY:
     2cf2. is used instead.

          >>> token_urlsafe(16)
          'Drmhze6EPcv0fN_81Bj-nA'

* Menu:

* How many bytes should tokens use?::


File: python.info,  Node: How many bytes should tokens use?,  Up: Generating tokens

5.15.3.3 How many bytes should tokens use?
..........................................

To be secure against brute-force attacks(1), tokens need to have
sufficient randomness.  Unfortunately, what is considered sufficient
will necessarily increase as computers get more powerful and able to
make more guesses in a shorter period.  As of 2015, it is believed that
32 bytes (256 bits) of randomness is sufficient for the typical use-case
expected for the ‘secrets’ module.

For those who want to manage their own token length, you can explicitly
specify how much randomness is used for tokens by giving an *note int:
257. argument to the various ‘token_*’ functions.  That argument is
taken as the number of bytes of randomness to use.

Otherwise, if no argument is provided, or if the argument is ‘None’, the
‘token_*’ functions use *note DEFAULT_ENTROPY: 2cf2. instead.

 -- Data: secrets.DEFAULT_ENTROPY

     Default number of bytes of randomness used by the ‘token_*’
     functions.

     The exact value is subject to change at any time, including during
     maintenance releases.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Brute-force_attack


File: python.info,  Node: Other functions,  Next: Recipes and best practices,  Prev: Generating tokens,  Up: secrets — Generate secure random numbers for managing secrets

5.15.3.4 Other functions
........................

 -- Function: secrets.compare_digest (a, b)

     Return ‘True’ if strings or *note bytes-like objects: d55. 'a' and
     'b' are equal, otherwise ‘False’, using a “constant-time compare”
     to reduce the risk of timing attacks(1).  See *note
     hmac.compare_digest(): 110d. for additional details.

   ---------- Footnotes ----------

   (1) https://codahale.com/a-lesson-in-timing-attacks/


File: python.info,  Node: Recipes and best practices,  Prev: Other functions,  Up: secrets — Generate secure random numbers for managing secrets

5.15.3.5 Recipes and best practices
...................................

This section shows recipes and best practices for using ‘secrets’ to
manage a basic level of security.

Generate an eight-character alphanumeric password:

     import string
     import secrets
     alphabet = string.ascii_letters + string.digits
     password = ''.join(secrets.choice(alphabet) for i in range(8))

     Note: Applications should not store passwords in a recoverable
     format(1), whether plain text or encrypted.  They should be salted
     and hashed using a cryptographically strong one-way (irreversible)
     hash function.

Generate a ten-character alphanumeric password with at least one
lowercase character, at least one uppercase character, and at least
three digits:

     import string
     import secrets
     alphabet = string.ascii_letters + string.digits
     while True:
         password = ''.join(secrets.choice(alphabet) for i in range(10))
         if (any(c.islower() for c in password)
                 and any(c.isupper() for c in password)
                 and sum(c.isdigit() for c in password) >= 3):
             break

Generate an XKCD-style passphrase(2):

     import secrets
     # On standard Linux systems, use a convenient dictionary file.
     # Other platforms may need to provide their own word-list.
     with open('/usr/share/dict/words') as f:
         words = [word.strip() for word in f]
         password = ' '.join(secrets.choice(words) for i in range(4))

Generate a hard-to-guess temporary URL containing a security token
suitable for password recovery applications:

     import secrets
     url = 'https://example.com/reset=' + secrets.token_urlsafe()

   ---------- Footnotes ----------

   (1) https://cwe.mitre.org/data/definitions/257.html

   (2) https://xkcd.com/936/


File: python.info,  Node: Generic Operating System Services,  Next: Command-line interface libraries,  Prev: Cryptographic Services,  Up: The Python Standard Library

5.16 Generic Operating System Services
======================================

The modules described in this chapter provide interfaces to operating
system features that are available on (almost) all operating systems,
such as files and a clock.  The interfaces are generally modeled after
the Unix or C interfaces, but they are available on most other systems
as well.  Here’s an overview:

* Menu:

* os — Miscellaneous operating system interfaces::
* io — Core tools for working with streams::
* time — Time access and conversions::
* logging — Logging facility for Python::
* logging.config — Logging configuration: logging config — Logging configuration.
* logging.handlers — Logging handlers: logging handlers — Logging handlers.
* platform — Access to underlying platform’s identifying data::
* errno — Standard errno system symbols::
* ctypes — A foreign function library for Python::


File: python.info,  Node: os — Miscellaneous operating system interfaces,  Next: io — Core tools for working with streams,  Up: Generic Operating System Services

5.16.1 ‘os’ — Miscellaneous operating system interfaces
-------------------------------------------------------

'Source code:' Lib/os.py(1)

__________________________________________________________________

This module provides a portable way of using operating system dependent
functionality.  If you just want to read or write a file see *note
open(): 51f, if you want to manipulate paths, see the *note os.path: a2.
module, and if you want to read all the lines in all the files on the
command line see the *note fileinput: 5b. module.  For creating
temporary files and directories see the *note tempfile: e0. module, and
for high-level file and directory handling see the *note shutil: c5.
module.

Notes on the availability of these functions:

   * The design of all built-in operating system dependent modules of
     Python is such that as long as the same functionality is available,
     it uses the same interface; for example, the function
     ‘os.stat(path)’ returns stat information about 'path' in the same
     format (which happens to have originated with the POSIX interface).

   * Extensions peculiar to a particular operating system are also
     available through the ‘os’ module, but using them is of course a
     threat to portability.

   * All functions accepting path or file names accept both bytes and
     string objects, and result in an object of the same type, if a path
     or file name is returned.

   * On VxWorks, os.popen, os.fork, os.execv and os.spawn*p* are not
     supported.

   * On WebAssembly platforms, Android and iOS, large parts of the ‘os’
     module are not available or behave differently.  APIs related to
     processes (e.g.  *note fork(): 197, *note execve(): 113d.) and
     resources (e.g.  *note nice(): 1145.) are not available.  Others
     like *note getuid(): 1632. and *note getpid(): 2cfe. are emulated
     or stubs.  WebAssembly platforms also lack support for signals
     (e.g.  *note kill(): 13b4, *note wait(): dc6.).

     Note: All functions in this module raise *note OSError: 41a. (or
     subclasses thereof) in the case of invalid or inaccessible file
     names and paths, or other arguments that have the correct type, but
     are not accepted by the operating system.

 -- Exception: os.error

     An alias for the built-in *note OSError: 41a. exception.

 -- Data: os.name

     The name of the operating system dependent module imported.  The
     following names have currently been registered: ‘'posix'’, ‘'nt'’,
     ‘'java'’.

     See also
     ........

     *note sys.platform: a9c. has a finer granularity.  *note
     os.uname(): 115a. gives system-dependent version information.

     The *note platform: aa. module provides detailed checks for the
     system’s identity.

* Menu:

* File Names, Command Line Arguments, and Environment Variables: File Names Command Line Arguments and Environment Variables.
* Python UTF-8 Mode::
* Process Parameters::
* File Object Creation::
* File Descriptor Operations::
* Files and Directories::
* Process Management::
* Interface to the scheduler::
* Miscellaneous System Information::
* Random numbers: Random numbers<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/os.py


File: python.info,  Node: File Names Command Line Arguments and Environment Variables,  Next: Python UTF-8 Mode,  Up: os — Miscellaneous operating system interfaces

5.16.1.1 File Names, Command Line Arguments, and Environment Variables
......................................................................

In Python, file names, command line arguments, and environment variables
are represented using the string type.  On some systems, decoding these
strings to and from bytes is necessary before passing them to the
operating system.  Python uses the *note filesystem encoding and error
handler: 53e. to perform this conversion (see *note
sys.getfilesystemencoding(): c7a.).

The *note filesystem encoding and error handler: 53e. are configured at
Python startup by the *note PyConfig_Read(): 793. function: see *note
filesystem_encoding: 3eb. and *note filesystem_errors: 3ec. members of
*note PyConfig: 3a9.

Changed in version 3.1: On some systems, conversion using the file
system encoding may fail.  In this case, Python uses the *note
surrogateescape encoding error handler: 259f, which means that
undecodable bytes are replaced by a Unicode character U+DC'xx' on
decoding, and these are again translated to the original byte on
encoding.

The *note file system encoding: 53e. must guarantee to successfully
decode all bytes below 128.  If the file system encoding fails to
provide this guarantee, API functions can raise *note UnicodeError:
12eb.

See also the *note locale encoding: 242.


File: python.info,  Node: Python UTF-8 Mode,  Next: Process Parameters,  Prev: File Names Command Line Arguments and Environment Variables,  Up: os — Miscellaneous operating system interfaces

5.16.1.2 Python UTF-8 Mode
..........................

Added in version 3.7: See PEP 540(1) for more details.

The Python UTF-8 Mode ignores the *note locale encoding: 242. and forces
the usage of the UTF-8 encoding:

   * Use UTF-8 as the *note filesystem encoding: 53e.

   * *note sys.getfilesystemencoding(): c7a. returns ‘'utf-8'’.

   * *note locale.getpreferredencoding(): 53d. returns ‘'utf-8'’ (the
     'do_setlocale' argument has no effect).

   * *note sys.stdin: 540, *note sys.stdout: aec, and *note sys.stderr:
     943. all use UTF-8 as their text encoding, with the
     ‘surrogateescape’ *note error handler: 1915. being enabled for
     ‘sys.stdin’ and ‘sys.stdout’ (‘sys.stderr’ continues to use
     ‘backslashreplace’ as it does in the default locale-aware mode)

   * On Unix, *note os.device_encoding(): 19db. returns ‘'utf-8'’ rather
     than the device encoding.

Note that the standard stream settings in UTF-8 mode can be overridden
by *note PYTHONIOENCODING: 1045. (just as they can be in the default
locale-aware mode).

As a consequence of the changes in those lower level APIs, other higher
level APIs also exhibit different default behaviours:

   * Command line arguments, environment variables and filenames are
     decoded to text using the UTF-8 encoding.

   * *note os.fsdecode(): c75. and *note os.fsencode(): c76. use the
     UTF-8 encoding.

   * *note open(): 51f, *note io.open(): 520, and *note codecs.open():
     743. use the UTF-8 encoding by default.  However, they still use
     the strict error handler by default so that attempting to open a
     binary file in text mode is likely to raise an exception rather
     than producing nonsense data.

The *note Python UTF-8 Mode: 659. is enabled if the LC_CTYPE locale is
‘C’ or ‘POSIX’ at Python startup (see the *note PyConfig_Read(): 793.
function).

It can be enabled or disabled using the *note -X utf8: 176. command line
option and the *note PYTHONUTF8: aee. environment variable.

If the *note PYTHONUTF8: aee. environment variable is not set at all,
then the interpreter defaults to using the current locale settings,
'unless' the current locale is identified as a legacy ASCII-based locale
(as described for *note PYTHONCOERCECLOCALE: aeb.), and locale coercion
is either disabled or fails.  In such legacy locales, the interpreter
will default to enabling UTF-8 mode unless explicitly instructed not to
do so.

The Python UTF-8 Mode can only be enabled at the Python startup.  Its
value can be read from *note sys.flags.utf8_mode: 68f.

See also the *note UTF-8 mode on Windows: 1fc7. and the *note filesystem
encoding and error handler: 53e.

See also
........

PEP 686(2)

     Python 3.15 will make *note Python UTF-8 Mode: 659. default.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0540/

   (2) https://peps.python.org/pep-0686/


File: python.info,  Node: Process Parameters,  Next: File Object Creation,  Prev: Python UTF-8 Mode,  Up: os — Miscellaneous operating system interfaces

5.16.1.3 Process Parameters
...........................

These functions and data items provide information and operate on the
current process and user.

 -- Function: os.ctermid ()

     Return the filename corresponding to the controlling terminal of
     the process.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.environ

     A *note mapping: 1200. object where keys and values are strings
     that represent the process environment.  For example,
     ‘environ['HOME']’ is the pathname of your home directory (on some
     platforms), and is equivalent to ‘getenv("HOME")’ in C.

     This mapping is captured the first time the ‘os’ module is
     imported, typically during Python startup as part of processing
     ‘site.py’.  Changes to the environment made after this time are not
     reflected in *note os.environ: 11fe, except for changes made by
     modifying ‘os.environ’ directly.

     This mapping may be used to modify the environment as well as query
     the environment.  *note putenv(): 925. will be called automatically
     when the mapping is modified.

     On Unix, keys and values use *note sys.getfilesystemencoding():
     c7a. and ‘'surrogateescape'’ error handler.  Use *note environb:
     125c. if you would like to use a different encoding.

     On Windows, the keys are converted to uppercase.  This also applies
     when getting, setting, or deleting an item.  For example,
     ‘environ['monty'] = 'python'’ maps the key ‘'MONTY'’ to the value
     ‘'python'’.

          Note: Calling *note putenv(): 925. directly does not change
          *note os.environ: 11fe, so it’s better to modify ‘os.environ’.

          Note: On some platforms, including FreeBSD and macOS, setting
          ‘environ’ may cause memory leaks.  Refer to the system
          documentation for ‘putenv()’.

     You can delete items in this mapping to unset environment
     variables.  *note unsetenv(): 924. will be called automatically
     when an item is deleted from *note os.environ: 11fe, and when one
     of the ‘pop()’ or ‘clear()’ methods is called.

     Changed in version 3.9: Updated to support PEP 584(1)’s merge (‘|’)
     and update (‘|=’) operators.

 -- Data: os.environb

     Bytes version of *note environ: 11fe.: a *note mapping: 1200.
     object where both keys and values are *note bytes: 1c2. objects
     representing the process environment.  ‘environ’ and ‘environb’ are
     synchronized (modifying ‘environb’ updates ‘environ’, and vice
     versa).

     ‘environb’ is only available if *note supports_bytes_environ: 125a.
     is ‘True’.

     Added in version 3.2.

     Changed in version 3.9: Updated to support PEP 584(2)’s merge (‘|’)
     and update (‘|=’) operators.

 -- Function: os.chdir (path)

 -- Function: os.fchdir (fd)

 -- Function: os.getcwd ()

     These functions are described in *note Files and Directories: 2d06.

 -- Function: os.fsencode (filename)

     Encode *note path-like: 2a0. 'filename' to the *note filesystem
     encoding and error handler: 53e.; return *note bytes: 1c2.
     unchanged.

     *note fsdecode(): c75. is the reverse function.

     Added in version 3.2.

     Changed in version 3.6: Support added to accept objects
     implementing the *note os.PathLike: c72. interface.

 -- Function: os.fsdecode (filename)

     Decode the *note path-like: 2a0. 'filename' from the *note
     filesystem encoding and error handler: 53e.; return *note str: 44f.
     unchanged.

     *note fsencode(): c76. is the reverse function.

     Added in version 3.2.

     Changed in version 3.6: Support added to accept objects
     implementing the *note os.PathLike: c72. interface.

 -- Function: os.fspath (path)

     Return the file system representation of the path.

     If *note str: 44f. or *note bytes: 1c2. is passed in, it is
     returned unchanged.  Otherwise *note __fspath__(): c73. is called
     and its value is returned as long as it is a ‘str’ or ‘bytes’
     object.  In all other cases, *note TypeError: 2c3. is raised.

     Added in version 3.6.

 -- Class: os.PathLike

     An *note abstract base class: 11fa. for objects representing a file
     system path, e.g.  *note pathlib.PurePath: 4a9.

     Added in version 3.6.

      -- Method: abstractmethod __fspath__ ()

          Return the file system path representation of the object.

          The method should only return a *note str: 44f. or *note
          bytes: 1c2. object, with the preference being for ‘str’.

 -- Function: os.getenv (key, default=None)

     Return the value of the environment variable 'key' as a string if
     it exists, or 'default' if it doesn’t.  'key' is a string.  Note
     that since ‘getenv()’ uses *note os.environ: 11fe, the mapping of
     ‘getenv()’ is similarly also captured on import, and the function
     may not reflect future environment changes.

     On Unix, keys and values are decoded with *note
     sys.getfilesystemencoding(): c7a. and ‘'surrogateescape'’ error
     handler.  Use *note os.getenvb(): 125b. if you would like to use a
     different encoding.

     *note Availability: 1ef7.: Unix, Windows.

 -- Function: os.getenvb (key, default=None)

     Return the value of the environment variable 'key' as bytes if it
     exists, or 'default' if it doesn’t.  'key' must be bytes.  Note
     that since ‘getenvb()’ uses *note os.environb: 125c, the mapping of
     ‘getenvb()’ is similarly also captured on import, and the function
     may not reflect future environment changes.

     ‘getenvb()’ is only available if *note supports_bytes_environ:
     125a. is ‘True’.

     *note Availability: 1ef7.: Unix.

     Added in version 3.2.

 -- Function: os.get_exec_path (env=None)

     Returns the list of directories that will be searched for a named
     executable, similar to a shell, when launching a process.  'env',
     when specified, should be an environment variable dictionary to
     lookup the PATH in.  By default, when 'env' is ‘None’, *note
     environ: 11fe. is used.

     Added in version 3.2.

 -- Function: os.getegid ()

     Return the effective group id of the current process.  This
     corresponds to the “set id” bit on the file being executed in the
     current process.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.geteuid ()

     Return the current process’s effective user id.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.getgid ()

     Return the real group id of the current process.

     *note Availability: 1ef7.: Unix.

     The function is a stub on WASI, see *note WebAssembly platforms:
     1910. for more information.

 -- Function: os.getgrouplist (user, group, /)

     Return list of group ids that 'user' belongs to.  If 'group' is not
     in the list, it is included; typically, 'group' is specified as the
     group ID field from the password record for 'user', because that
     group ID will otherwise be potentially omitted.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Function: os.getgroups ()

     Return list of supplemental group ids associated with the current
     process.

     *note Availability: 1ef7.: Unix, not WASI.

          Note: On macOS, ‘getgroups()’ behavior differs somewhat from
          other Unix platforms.  If the Python interpreter was built
          with a deployment target of ‘10.5’ or earlier, ‘getgroups()’
          returns the list of effective group ids associated with the
          current user process; this list is limited to a system-defined
          number of entries, typically 16, and may be modified by calls
          to *note setgroups(): 2d0c. if suitably privileged.  If built
          with a deployment target greater than ‘10.5’, ‘getgroups()’
          returns the current group access list for the user associated
          with the effective user id of the process; the group access
          list may change over the lifetime of the process, it is not
          affected by calls to ‘setgroups()’, and its length is not
          limited to 16.  The deployment target value,
          ‘MACOSX_DEPLOYMENT_TARGET’, can be obtained with *note
          sysconfig.get_config_var(): 1068.

 -- Function: os.getlogin ()

     Return the name of the user logged in on the controlling terminal
     of the process.  For most purposes, it is more useful to use *note
     getpass.getuser(): 41b. since the latter checks the environment
     variables ‘LOGNAME’ or ‘USERNAME’ to find out who the user is, and
     falls back to ‘pwd.getpwuid(os.getuid())[0]’ to get the login name
     of the current real user id.

     *note Availability: 1ef7.: Unix, Windows, not WASI.

 -- Function: os.getpgid (pid)

     Return the process group id of the process with process id 'pid'.
     If 'pid' is 0, the process group id of the current process is
     returned.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.getpgrp ()

     Return the id of the current process group.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.getpid ()

     Return the current process id.

     The function is a stub on WASI, see *note WebAssembly platforms:
     1910. for more information.

 -- Function: os.getppid ()

     Return the parent’s process id.  When the parent process has
     exited, on Unix the id returned is the one of the init process (1),
     on Windows it is still the same id, which may be already reused by
     another process.

     *note Availability: 1ef7.: Unix, Windows, not WASI.

     Changed in version 3.2: Added support for Windows.

 -- Function: os.getpriority (which, who)

     Get program scheduling priority.  The value 'which' is one of *note
     PRIO_PROCESS: 2d0f, *note PRIO_PGRP: 2d10, or *note PRIO_USER:
     2d11, and 'who' is interpreted relative to 'which' (a process
     identifier for ‘PRIO_PROCESS’, process group identifier for
     ‘PRIO_PGRP’, and a user ID for ‘PRIO_USER’).  A zero value for
     'who' denotes (respectively) the calling process, the process group
     of the calling process, or the real user ID of the calling process.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Data: os.PRIO_PROCESS
 -- Data: os.PRIO_PGRP
 -- Data: os.PRIO_USER

     Parameters for the *note getpriority(): 1143. and *note
     setpriority(): 1144. functions.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Data: os.PRIO_DARWIN_THREAD
 -- Data: os.PRIO_DARWIN_PROCESS
 -- Data: os.PRIO_DARWIN_BG
 -- Data: os.PRIO_DARWIN_NONUI

     Parameters for the *note getpriority(): 1143. and *note
     setpriority(): 1144. functions.

     *note Availability: 1ef7.: macOS

     Added in version 3.12.

 -- Function: os.getresuid ()

     Return a tuple (ruid, euid, suid) denoting the current process’s
     real, effective, and saved user ids.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.2.

 -- Function: os.getresgid ()

     Return a tuple (rgid, egid, sgid) denoting the current process’s
     real, effective, and saved group ids.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.2.

 -- Function: os.getuid ()

     Return the current process’s real user id.

     *note Availability: 1ef7.: Unix.

     The function is a stub on WASI, see *note WebAssembly platforms:
     1910. for more information.

 -- Function: os.initgroups (username, gid, /)

     Call the system ‘initgroups()’ to initialize the group access list
     with all of the groups of which the specified username is a member,
     plus the specified group id.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

     Added in version 3.2.

 -- Function: os.putenv (key, value, /)

     Set the environment variable named 'key' to the string 'value'.
     Such changes to the environment affect subprocesses started with
     *note os.system(): 14ac, *note popen(): a96. or *note fork(): 197.
     and *note execv(): 2d16.

     Assignments to items in *note os.environ: 11fe. are automatically
     translated into corresponding calls to ‘putenv()’; however, calls
     to ‘putenv()’ don’t update ‘os.environ’, so it is actually
     preferable to assign to items of ‘os.environ’.  This also applies
     to *note getenv(): 2d07. and *note getenvb(): 125b, which
     respectively use ‘os.environ’ and *note os.environb: 125c. in their
     implementations.

          Note: On some platforms, including FreeBSD and macOS, setting
          ‘environ’ may cause memory leaks.  Refer to the system
          documentation for ‘putenv()’.

     Raises an *note auditing event: 1a15. ‘os.putenv’ with arguments
     ‘key’, ‘value’.

     Changed in version 3.9: The function is now always available.

 -- Function: os.setegid (egid, /)

     Set the current process’s effective group id.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.seteuid (euid, /)

     Set the current process’s effective user id.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.setgid (gid, /)

     Set the current process’ group id.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.setgroups (groups, /)

     Set the list of supplemental group ids associated with the current
     process to 'groups'.  'groups' must be a sequence, and each element
     must be an integer identifying a group.  This operation is
     typically available only to the superuser.

     *note Availability: 1ef7.: Unix, not WASI.

          Note: On macOS, the length of 'groups' may not exceed the
          system-defined maximum number of effective group ids,
          typically 16.  See the documentation for *note getgroups():
          2d0b. for cases where it may not return the same group list
          set by calling setgroups().

 -- Function: os.setns (fd, nstype=0)

     Reassociate the current thread with a Linux namespace.  See the
     ‘setns(2)(3)’ and ‘namespaces(7)(4)’ man pages for more details.

     If 'fd' refers to a ‘/proc/`pid'/ns/’ link, ‘setns()’ reassociates
     the calling thread with the namespace associated with that link,
     and 'nstype' may be set to one of the *note CLONE_NEW* constants:
     2d1a. to impose constraints on the operation (‘0’ means no
     constraints).

     Since Linux 5.8, 'fd' may refer to a PID file descriptor obtained
     from *note pidfd_open(): 47d.  In this case, ‘setns()’ reassociates
     the calling thread into one or more of the same namespaces as the
     thread referred to by 'fd'.  This is subject to any constraints
     imposed by 'nstype', which is a bit mask combining one or more of
     the *note CLONE_NEW* constants: 2d1a, e.g.  ‘setns(fd,
     os.CLONE_NEWUTS | os.CLONE_NEWPID)’.  The caller’s memberships in
     unspecified namespaces are left unchanged.

     'fd' can be any object with a *note fileno(): 15f5. method, or a
     raw file descriptor.

     This example reassociates the thread with the ‘init’ process’s
     network namespace:

          fd = os.open("/proc/1/ns/net", os.O_RDONLY)
          os.setns(fd, os.CLONE_NEWNET)
          os.close(fd)

     *note Availability: 1ef7.: Linux >= 3.0 with glibc >= 2.14.

     Added in version 3.12.

     See also
     ........

     The *note unshare(): 18e6. function.

 -- Function: os.setpgrp ()

     Call the system call ‘setpgrp()’ or ‘setpgrp(0, 0)’ depending on
     which version is implemented (if any).  See the Unix manual for the
     semantics.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.setpgid (pid, pgrp, /)

     Call the system call ‘setpgid()’ to set the process group id of the
     process with id 'pid' to the process group with id 'pgrp'.  See the
     Unix manual for the semantics.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.setpriority (which, who, priority)

     Set program scheduling priority.  The value 'which' is one of *note
     PRIO_PROCESS: 2d0f, *note PRIO_PGRP: 2d10, or *note PRIO_USER:
     2d11, and 'who' is interpreted relative to 'which' (a process
     identifier for ‘PRIO_PROCESS’, process group identifier for
     ‘PRIO_PGRP’, and a user ID for ‘PRIO_USER’).  A zero value for
     'who' denotes (respectively) the calling process, the process group
     of the calling process, or the real user ID of the calling process.
     'priority' is a value in the range -20 to 19.  The default priority
     is 0; lower priorities cause more favorable scheduling.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Function: os.setregid (rgid, egid, /)

     Set the current process’s real and effective group ids.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.setresgid (rgid, egid, sgid, /)

     Set the current process’s real, effective, and saved group ids.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

     Added in version 3.2.

 -- Function: os.setresuid (ruid, euid, suid, /)

     Set the current process’s real, effective, and saved user ids.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

     Added in version 3.2.

 -- Function: os.setreuid (ruid, euid, /)

     Set the current process’s real and effective user ids.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.getsid (pid, /)

     Call the system call ‘getsid()’.  See the Unix manual for the
     semantics.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.setsid ()

     Call the system call ‘setsid()’.  See the Unix manual for the
     semantics.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.setuid (uid, /)

     Set the current process’s user id.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

 -- Function: os.strerror (code, /)

     Return the error message corresponding to the error code in 'code'.
     On platforms where ‘strerror()’ returns ‘NULL’ when given an
     unknown error number, *note ValueError: 202. is raised.

 -- Data: os.supports_bytes_environ

     ‘True’ if the native OS type of the environment is bytes (eg.
     ‘False’ on Windows).

     Added in version 3.2.

 -- Function: os.umask (mask, /)

     Set the current numeric umask and return the previous umask.

     The function is a stub on WASI, see *note WebAssembly platforms:
     1910. for more information.

 -- Function: os.uname ()

     Returns information identifying the current operating system.  The
     return value is an object with five attributes:

        * ‘sysname’ - operating system name

        * ‘nodename’ - name of machine on network
          (implementation-defined)

        * ‘release’ - operating system release

        * ‘version’ - operating system version

        * ‘machine’ - hardware identifier

     For backwards compatibility, this object is also iterable, behaving
     like a five-tuple containing ‘sysname’, ‘nodename’, ‘release’,
     ‘version’, and ‘machine’ in that order.

     Some systems truncate ‘nodename’ to 8 characters or to the leading
     component; a better way to get the hostname is *note
     socket.gethostname(): 2d23. or even
     ‘socket.gethostbyaddr(socket.gethostname())’.

     On macOS, iOS and Android, this returns the 'kernel' name and
     version (i.e., ‘'Darwin'’ on macOS and iOS; ‘'Linux'’ on Android).
     *note platform.uname(): 1bc2. can be used to get the user-facing
     operating system name and version on iOS and Android.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.3: Return type changed from a tuple to a
     tuple-like object with named attributes.

 -- Function: os.unsetenv (key, /)

     Unset (delete) the environment variable named 'key'.  Such changes
     to the environment affect subprocesses started with *note
     os.system(): 14ac, *note popen(): a96. or *note fork(): 197. and
     *note execv(): 2d16.

     Deletion of items in *note os.environ: 11fe. is automatically
     translated into a corresponding call to ‘unsetenv()’; however,
     calls to ‘unsetenv()’ don’t update ‘os.environ’, so it is actually
     preferable to delete items of ‘os.environ’.

     Raises an *note auditing event: 1a15. ‘os.unsetenv’ with argument
     ‘key’.

     Changed in version 3.9: The function is now always available and is
     also available on Windows.

 -- Function: os.unshare (flags)

     Disassociate parts of the process execution context, and move them
     into a newly created namespace.  See the ‘unshare(2)(5)’ man page
     for more details.  The 'flags' argument is a bit mask, combining
     zero or more of the *note CLONE_* constants: 2d1a, that specifies
     which parts of the execution context should be unshared from their
     existing associations and moved to a new namespace.  If the 'flags'
     argument is ‘0’, no changes are made to the calling process’s
     execution context.

     *note Availability: 1ef7.: Linux >= 2.6.16.

     Added in version 3.12.

     See also
     ........

     The *note setns(): 18e5. function.

Flags to the *note unshare(): 18e6. function, if the implementation
supports them.  See ‘unshare(2)(6)’ in the Linux manual for their exact
effect and availability.

 -- Data: os.CLONE_FILES
 -- Data: os.CLONE_FS
 -- Data: os.CLONE_NEWCGROUP
 -- Data: os.CLONE_NEWIPC
 -- Data: os.CLONE_NEWNET
 -- Data: os.CLONE_NEWNS
 -- Data: os.CLONE_NEWPID
 -- Data: os.CLONE_NEWTIME
 -- Data: os.CLONE_NEWUSER
 -- Data: os.CLONE_NEWUTS
 -- Data: os.CLONE_SIGHAND
 -- Data: os.CLONE_SYSVSEM
 -- Data: os.CLONE_THREAD
 -- Data: os.CLONE_VM

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0584/

   (2) https://peps.python.org/pep-0584/

   (3) https://manpages.debian.org/setns(2)

   (4) https://manpages.debian.org/namespaces(7)

   (5) https://manpages.debian.org/unshare(2)

   (6) https://manpages.debian.org/unshare(2)


File: python.info,  Node: File Object Creation,  Next: File Descriptor Operations,  Prev: Process Parameters,  Up: os — Miscellaneous operating system interfaces

5.16.1.4 File Object Creation
.............................

These functions create new *note file objects: 1208.  (See also *note
open(): dc0. for opening file descriptors.)

 -- Function: os.fdopen (fd, *args, **kwargs)

     Return an open file object connected to the file descriptor 'fd'.
     This is an alias of the *note open(): 51f. built-in function and
     accepts the same arguments.  The only difference is that the first
     argument of ‘fdopen()’ must always be an integer.


File: python.info,  Node: File Descriptor Operations,  Next: Files and Directories,  Prev: File Object Creation,  Up: os — Miscellaneous operating system interfaces

5.16.1.5 File Descriptor Operations
...................................

These functions operate on I/O streams referenced using file
descriptors.

File descriptors are small integers corresponding to a file that has
been opened by the current process.  For example, standard input is
usually file descriptor 0, standard output is 1, and standard error is
2.  Further files opened by a process will then be assigned 3, 4, 5, and
so forth.  The name “file descriptor” is slightly deceptive; on Unix
platforms, sockets and pipes are also referenced by file descriptors.

The *note fileno(): 15f5. method can be used to obtain the file
descriptor associated with a *note file object: 1208. when required.
Note that using the file descriptor directly will bypass the file object
methods, ignoring aspects such as internal buffering of data.

 -- Function: os.close (fd)

     Close file descriptor 'fd'.

          Note: This function is intended for low-level I/O and must be
          applied to a file descriptor as returned by *note os.open():
          dc0. or *note pipe(): 190a.  To close a “file object” returned
          by the built-in function *note open(): 51f. or by *note
          popen(): a96. or *note fdopen(): 20e3, use its *note close():
          1f6. method.

 -- Function: os.closerange (fd_low, fd_high, /)

     Close all file descriptors from 'fd_low' (inclusive) to 'fd_high'
     (exclusive), ignoring errors.  Equivalent to (but much faster
     than):

          for fd in range(fd_low, fd_high):
              try:
                  os.close(fd)
              except OSError:
                  pass

 -- Function: os.copy_file_range (src, dst, count, offset_src=None,
          offset_dst=None)

     Copy 'count' bytes from file descriptor 'src', starting from offset
     'offset_src', to file descriptor 'dst', starting from offset
     'offset_dst'.  If 'offset_src' is ‘None’, then 'src' is read from
     the current position; respectively for 'offset_dst'.

     In Linux kernel older than 5.3, the files pointed to by 'src' and
     'dst' must reside in the same filesystem, otherwise an *note
     OSError: 41a. is raised with *note errno: 15fa. set to *note
     errno.EXDEV: 2d38.

     This copy is done without the additional cost of transferring data
     from the kernel to user space and then back into the kernel.
     Additionally, some filesystems could implement extra optimizations,
     such as the use of reflinks (i.e., two or more inodes that share
     pointers to the same copy-on-write disk blocks; supported file
     systems include btrfs and XFS) and server-side copy (in the case of
     NFS).

     The function copies bytes between two file descriptors.  Text
     options, like the encoding and the line ending, are ignored.

     The return value is the amount of bytes copied.  This could be less
     than the amount requested.

          Note: On Linux, *note os.copy_file_range(): 2d37. should not
          be used for copying a range of a pseudo file from a special
          filesystem like procfs and sysfs.  It will always copy no
          bytes and return 0 as if the file was empty because of a known
          Linux kernel issue.

     *note Availability: 1ef7.: Linux >= 4.5 with glibc >= 2.27.

     Added in version 3.8.

 -- Function: os.device_encoding (fd)

     Return a string describing the encoding of the device associated
     with 'fd' if it is connected to a terminal; else return *note None:
     678.

     On Unix, if the *note Python UTF-8 Mode: 659. is enabled, return
     ‘'UTF-8'’ rather than the device encoding.

     Changed in version 3.10: On Unix, the function now implements the
     Python UTF-8 Mode.

 -- Function: os.dup (fd, /)

     Return a duplicate of file descriptor 'fd'.  The new file
     descriptor is *note non-inheritable: f30.

     On Windows, when duplicating a standard stream (0: stdin, 1:
     stdout, 2: stderr), the new file descriptor is *note inheritable:
     f30.

     *note Availability: 1ef7.: not WASI.

     Changed in version 3.4: The new file descriptor is now
     non-inheritable.

 -- Function: os.dup2 (fd, fd2, inheritable=True)

     Duplicate file descriptor 'fd' to 'fd2', closing the latter first
     if necessary.  Return 'fd2'.  The new file descriptor is *note
     inheritable: f30. by default or non-inheritable if 'inheritable' is
     ‘False’.

     *note Availability: 1ef7.: not WASI.

     Changed in version 3.4: Add the optional 'inheritable' parameter.

     Changed in version 3.7: Return 'fd2' on success.  Previously,
     ‘None’ was always returned.

 -- Function: os.fchmod (fd, mode)

     Change the mode of the file given by 'fd' to the numeric 'mode'.
     See the docs for *note chmod(): 21b. for possible values of 'mode'.
     As of Python 3.3, this is equivalent to ‘os.chmod(fd, mode)’.

     Raises an *note auditing event: 1a15. ‘os.chmod’ with arguments
     ‘path’, ‘mode’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix, Windows.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

     Changed in version 3.13: Added support on Windows.

 -- Function: os.fchown (fd, uid, gid)

     Change the owner and group id of the file given by 'fd' to the
     numeric 'uid' and 'gid'.  To leave one of the ids unchanged, set it
     to -1.  See *note chown(): 1132.  As of Python 3.3, this is
     equivalent to ‘os.chown(fd, uid, gid)’.

     Raises an *note auditing event: 1a15. ‘os.chown’ with arguments
     ‘path’, ‘uid’, ‘gid’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

 -- Function: os.fdatasync (fd)

     Force write of file with filedescriptor 'fd' to disk.  Does not
     force update of metadata.

     *note Availability: 1ef7.: Unix.

          Note: This function is not available on MacOS.

 -- Function: os.fpathconf (fd, name, /)

     Return system configuration information relevant to an open file.
     'name' specifies the configuration value to retrieve; it may be a
     string which is the name of a defined system value; these names are
     specified in a number of standards (POSIX.1, Unix 95, Unix 98, and
     others).  Some platforms define additional names as well.  The
     names known to the host operating system are given in the
     ‘pathconf_names’ dictionary.  For configuration variables not
     included in that mapping, passing an integer for 'name' is also
     accepted.

     If 'name' is a string and is not known, *note ValueError: 202. is
     raised.  If a specific value for 'name' is not supported by the
     host system, even if it is included in ‘pathconf_names’, an *note
     OSError: 41a. is raised with *note errno.EINVAL: 1b7f. for the
     error number.

     As of Python 3.3, this is equivalent to ‘os.pathconf(fd, name)’.

     *note Availability: 1ef7.: Unix.

 -- Function: os.fstat (fd)

     Get the status of the file descriptor 'fd'.  Return a *note
     stat_result: 1510. object.

     As of Python 3.3, this is equivalent to ‘os.stat(fd)’.

     See also
     ........

     The *note stat(): 4a3. function.

 -- Function: os.fstatvfs (fd, /)

     Return information about the filesystem containing the file
     associated with file descriptor 'fd', like *note statvfs(): 1140.
     As of Python 3.3, this is equivalent to ‘os.statvfs(fd)’.

     *note Availability: 1ef7.: Unix.

 -- Function: os.fsync (fd)

     Force write of file with filedescriptor 'fd' to disk.  On Unix,
     this calls the native ‘fsync()’ function; on Windows, the MS
     ‘_commit()’ function.

     If you’re starting with a buffered Python *note file object: 1208.
     'f', first do ‘f.flush()’, and then do ‘os.fsync(f.fileno())’, to
     ensure that all internal buffers associated with 'f' are written to
     disk.

     *note Availability: 1ef7.: Unix, Windows.

 -- Function: os.ftruncate (fd, length, /)

     Truncate the file corresponding to file descriptor 'fd', so that it
     is at most 'length' bytes in size.  As of Python 3.3, this is
     equivalent to ‘os.truncate(fd, length)’.

     Raises an *note auditing event: 1a15. ‘os.truncate’ with arguments
     ‘fd’, ‘length’.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.5: Added support for Windows

 -- Function: os.get_blocking (fd, /)

     Get the blocking mode of the file descriptor: ‘False’ if the *note
     O_NONBLOCK: e6e. flag is set, ‘True’ if the flag is cleared.

     See also *note set_blocking(): e6d. and *note
     socket.socket.setblocking(): 2d3a.

     *note Availability: 1ef7.: Unix, Windows.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

     On Windows, this function is limited to pipes.

     Added in version 3.5.

     Changed in version 3.12: Added support for pipes on Windows.

 -- Function: os.grantpt (fd, /)

     Grant access to the slave pseudo-terminal device associated with
     the master pseudo-terminal device to which the file descriptor 'fd'
     refers.  The file descriptor 'fd' is not closed upon failure.

     Calls the C standard library function ‘grantpt()’.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.13.

 -- Function: os.isatty (fd, /)

     Return ‘True’ if the file descriptor 'fd' is open and connected to
     a tty(-like) device, else ‘False’.

 -- Function: os.lockf (fd, cmd, len, /)

     Apply, test or remove a POSIX lock on an open file descriptor.
     'fd' is an open file descriptor.  'cmd' specifies the command to
     use - one of *note F_LOCK: 2d3b, *note F_TLOCK: 2d3c, *note
     F_ULOCK: 2d3d. or *note F_TEST: 2d3e.  'len' specifies the section
     of the file to lock.

     Raises an *note auditing event: 1a15. ‘os.lockf’ with arguments
     ‘fd’, ‘cmd’, ‘len’.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Data: os.F_LOCK
 -- Data: os.F_TLOCK
 -- Data: os.F_ULOCK
 -- Data: os.F_TEST

     Flags that specify what action *note lockf(): 1157. will take.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.login_tty (fd, /)

     Prepare the tty of which fd is a file descriptor for a new login
     session.  Make the calling process a session leader; make the tty
     the controlling tty, the stdin, the stdout, and the stderr of the
     calling process; close fd.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.11.

 -- Function: os.lseek (fd, pos, whence, /)

     Set the current position of file descriptor 'fd' to position 'pos',
     modified by 'whence', and return the new position in bytes relative
     to the start of the file.  Valid values for 'whence' are:

        * *note SEEK_SET: 12d4. or ‘0’ – set 'pos' relative to the
          beginning of the file

        * *note SEEK_CUR: 12d5. or ‘1’ – set 'pos' relative to the
          current file position

        * *note SEEK_END: 12d6. or ‘2’ – set 'pos' relative to the end
          of the file

        * *note SEEK_HOLE: 2d3f. – set 'pos' to the next data location,
          relative to 'pos'

        * *note SEEK_DATA: 2d40. – set 'pos' to the next data hole,
          relative to 'pos'

     Changed in version 3.3: Add support for ‘SEEK_HOLE’ and
     ‘SEEK_DATA’.

 -- Data: os.SEEK_SET
 -- Data: os.SEEK_CUR
 -- Data: os.SEEK_END

     Parameters to the *note lseek(): 115b. function and the *note
     seek(): 12d3. method on *note file-like objects: 1208, for whence
     to adjust the file position indicator.

     *note SEEK_SET: 12d4.

          Adjust the file position relative to the beginning of the
          file.

     *note SEEK_CUR: 12d5.

          Adjust the file position relative to the current file
          position.

     *note SEEK_END: 12d6.

          Adjust the file position relative to the end of the file.

     Their values are 0, 1, and 2, respectively.

 -- Data: os.SEEK_HOLE
 -- Data: os.SEEK_DATA

     Parameters to the *note lseek(): 115b. function and the *note
     seek(): 12d3. method on *note file-like objects: 1208, for seeking
     file data and holes on sparsely allocated files.

     ‘SEEK_DATA’

          Adjust the file offset to the next location containing data,
          relative to the seek position.

     ‘SEEK_HOLE’

          Adjust the file offset to the next location containing a hole,
          relative to the seek position.  A hole is defined as a
          sequence of zeros.

          Note: These operations only make sense for filesystems that
          support them.

     *note Availability: 1ef7.: Linux >= 3.1, macOS, Unix

     Added in version 3.3.

 -- Function: os.open (path, flags, mode=0o777, *, dir_fd=None)

     Open the file 'path' and set various flags according to 'flags' and
     possibly its mode according to 'mode'.  When computing 'mode', the
     current umask value is first masked out.  Return the file
     descriptor for the newly opened file.  The new file descriptor is
     *note non-inheritable: f30.

     For a description of the flag and mode values, see the C run-time
     documentation; flag constants (like *note O_RDONLY: 2d41. and *note
     O_WRONLY: 2d42.) are defined in the ‘os’ module.  In particular, on
     Windows adding *note O_BINARY: 2d43. is needed to open files in
     binary mode.

     This function can support *note paths relative to directory
     descriptors: 112e. with the 'dir_fd' parameter.

     Raises an *note auditing event: 1a15. ‘open’ with arguments ‘path’,
     ‘mode’, ‘flags’.

     Changed in version 3.4: The new file descriptor is now
     non-inheritable.

          Note: This function is intended for low-level I/O. For normal
          usage, use the built-in function ‘open()’, which returns a
          *note file object: 1208. with *note read(): 1372. and *note
          write(): d02. methods.  To wrap a file descriptor in a file
          object, use *note fdopen(): 20e3.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the function now
     retries the system call instead of raising an *note
     InterruptedError: db6. exception (see PEP 475(1) for the
     rationale).

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

The following constants are options for the 'flags' parameter to the
*note open(): dc0. function.  They can be combined using the bitwise OR
operator ‘|’.  Some of them are not available on all platforms.  For
descriptions of their availability and use, consult the ‘open(2)(2)’
manual page on Unix or the MSDN(3) on Windows.

 -- Data: os.O_RDONLY
 -- Data: os.O_WRONLY
 -- Data: os.O_RDWR
 -- Data: os.O_APPEND
 -- Data: os.O_CREAT
 -- Data: os.O_EXCL
 -- Data: os.O_TRUNC

     The above constants are available on Unix and Windows.

 -- Data: os.O_DSYNC
 -- Data: os.O_RSYNC
 -- Data: os.O_SYNC
 -- Data: os.O_NDELAY
 -- Data: os.O_NONBLOCK
 -- Data: os.O_NOCTTY
 -- Data: os.O_CLOEXEC

     The above constants are only available on Unix.

     Changed in version 3.3: Add ‘O_CLOEXEC’ constant.

 -- Data: os.O_BINARY
 -- Data: os.O_NOINHERIT
 -- Data: os.O_SHORT_LIVED
 -- Data: os.O_TEMPORARY
 -- Data: os.O_RANDOM
 -- Data: os.O_SEQUENTIAL
 -- Data: os.O_TEXT

     The above constants are only available on Windows.

 -- Data: os.O_EVTONLY
 -- Data: os.O_FSYNC
 -- Data: os.O_SYMLINK
 -- Data: os.O_NOFOLLOW_ANY

     The above constants are only available on macOS.

     Changed in version 3.10: Add ‘O_EVTONLY’, ‘O_FSYNC’, ‘O_SYMLINK’
     and ‘O_NOFOLLOW_ANY’ constants.

 -- Data: os.O_ASYNC
 -- Data: os.O_DIRECT
 -- Data: os.O_DIRECTORY
 -- Data: os.O_NOFOLLOW
 -- Data: os.O_NOATIME
 -- Data: os.O_PATH
 -- Data: os.O_TMPFILE
 -- Data: os.O_SHLOCK
 -- Data: os.O_EXLOCK

     The above constants are extensions and not present if they are not
     defined by the C library.

     Changed in version 3.4: Add ‘O_PATH’ on systems that support it.
     Add ‘O_TMPFILE’, only available on Linux Kernel 3.11 or newer.

 -- Function: os.openpty ()

     Open a new pseudo-terminal pair.  Return a pair of file descriptors
     ‘(master, slave)’ for the pty and the tty, respectively.  The new
     file descriptors are *note non-inheritable: f30.  For a (slightly)
     more portable approach, use the *note pty: b1. module.

     *note Availability: 1ef7.: Unix, not WASI.

     Changed in version 3.4: The new file descriptors are now
     non-inheritable.

 -- Function: os.pipe ()

     Create a pipe.  Return a pair of file descriptors ‘(r, w)’ usable
     for reading and writing, respectively.  The new file descriptor is
     *note non-inheritable: f30.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.4: The new file descriptors are now
     non-inheritable.

 -- Function: os.pipe2 (flags, /)

     Create a pipe with 'flags' set atomically.  'flags' can be
     constructed by ORing together one or more of these values: *note
     O_NONBLOCK: e6e, *note O_CLOEXEC: 10ba.  Return a pair of file
     descriptors ‘(r, w)’ usable for reading and writing, respectively.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Function: os.posix_fallocate (fd, offset, len, /)

     Ensures that enough disk space is allocated for the file specified
     by 'fd' starting from 'offset' and continuing for 'len' bytes.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.posix_fadvise (fd, offset, len, advice, /)

     Announces an intention to access data in a specific pattern thus
     allowing the kernel to make optimizations.  The advice applies to
     the region of the file specified by 'fd' starting at 'offset' and
     continuing for 'len' bytes.  'advice' is one of *note
     POSIX_FADV_NORMAL: 2d59, *note POSIX_FADV_SEQUENTIAL: 2d5a, *note
     POSIX_FADV_RANDOM: 2d5b, *note POSIX_FADV_NOREUSE: 2d5c, *note
     POSIX_FADV_WILLNEED: 2d5d. or *note POSIX_FADV_DONTNEED: 2d5e.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Data: os.POSIX_FADV_NORMAL
 -- Data: os.POSIX_FADV_SEQUENTIAL
 -- Data: os.POSIX_FADV_RANDOM
 -- Data: os.POSIX_FADV_NOREUSE
 -- Data: os.POSIX_FADV_WILLNEED
 -- Data: os.POSIX_FADV_DONTNEED

     Flags that can be used in 'advice' in *note posix_fadvise(): dc1.
     that specify the access pattern that is likely to be used.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.pread (fd, n, offset, /)

     Read at most 'n' bytes from file descriptor 'fd' at a position of
     'offset', leaving the file offset unchanged.

     Return a bytestring containing the bytes read.  If the end of the
     file referred to by 'fd' has been reached, an empty bytes object is
     returned.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.posix_openpt (oflag, /)

     Open and return a file descriptor for a master pseudo-terminal
     device.

     Calls the C standard library function ‘posix_openpt()’.  The
     'oflag' argument is used to set file status flags and file access
     modes as specified in the manual page of ‘posix_openpt()’ of your
     system.

     The returned file descriptor is *note non-inheritable: f30.  If the
     value *note O_CLOEXEC: 10ba. is available on the system, it is
     added to 'oflag'.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.13.

 -- Function: os.preadv (fd, buffers, offset, flags=0, /)

     Read from a file descriptor 'fd' at a position of 'offset' into
     mutable *note bytes-like objects: d55. 'buffers', leaving the file
     offset unchanged.  Transfer data into each buffer until it is full
     and then move on to the next buffer in the sequence to hold the
     rest of the data.

     The flags argument contains a bitwise OR of zero or more of the
     following flags:

        - *note RWF_HIPRI: 2d5f.

        - *note RWF_NOWAIT: 2d60.

     Return the total number of bytes actually read which can be less
     than the total capacity of all the objects.

     The operating system may set a limit (*note sysconf(): 1670. value
     ‘'SC_IOV_MAX'’) on the number of buffers that can be used.

     Combine the functionality of *note os.readv(): b7a. and *note
     os.pread(): b7b.

     *note Availability: 1ef7.: Linux >= 2.6.30, FreeBSD >= 6.0, OpenBSD
     >= 2.7, AIX >= 7.1.

     Using flags requires Linux >= 4.6.

     Added in version 3.7.

 -- Data: os.RWF_NOWAIT

     Do not wait for data which is not immediately available.  If this
     flag is specified, the system call will return instantly if it
     would have to read data from the backing storage or wait for a
     lock.

     If some data was successfully read, it will return the number of
     bytes read.  If no bytes were read, it will return ‘-1’ and set
     errno to *note errno.EAGAIN: 2457.

     *note Availability: 1ef7.: Linux >= 4.14.

     Added in version 3.7.

 -- Data: os.RWF_HIPRI

     High priority read/write.  Allows block-based filesystems to use
     polling of the device, which provides lower latency, but may use
     additional resources.

     Currently, on Linux, this feature is usable only on a file
     descriptor opened using the *note O_DIRECT: 2d54. flag.

     *note Availability: 1ef7.: Linux >= 4.6.

     Added in version 3.7.

 -- Function: os.ptsname (fd, /)

     Return the name of the slave pseudo-terminal device associated with
     the master pseudo-terminal device to which the file descriptor 'fd'
     refers.  The file descriptor 'fd' is not closed upon failure.

     Calls the reentrant C standard library function ‘ptsname_r()’ if it
     is available; otherwise, the C standard library function
     ‘ptsname()’, which is not guaranteed to be thread-safe, is called.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.13.

 -- Function: os.pwrite (fd, str, offset, /)

     Write the bytestring in 'str' to file descriptor 'fd' at position
     of 'offset', leaving the file offset unchanged.

     Return the number of bytes actually written.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.pwritev (fd, buffers, offset, flags=0, /)

     Write the 'buffers' contents to file descriptor 'fd' at an offset
     'offset', leaving the file offset unchanged.  'buffers' must be a
     sequence of *note bytes-like objects: d55.  Buffers are processed
     in array order.  Entire contents of the first buffer is written
     before proceeding to the second, and so on.

     The flags argument contains a bitwise OR of zero or more of the
     following flags:

        - *note RWF_DSYNC: 2d61.

        - *note RWF_SYNC: 2d62.

        - *note RWF_APPEND: 1ad4.

     Return the total number of bytes actually written.

     The operating system may set a limit (*note sysconf(): 1670. value
     ‘'SC_IOV_MAX'’) on the number of buffers that can be used.

     Combine the functionality of *note os.writev(): b7d. and *note
     os.pwrite(): b7e.

     *note Availability: 1ef7.: Linux >= 2.6.30, FreeBSD >= 6.0, OpenBSD
     >= 2.7, AIX >= 7.1.

     Using flags requires Linux >= 4.6.

     Added in version 3.7.

 -- Data: os.RWF_DSYNC

     Provide a per-write equivalent of the *note O_DSYNC: 2d48. *note
     os.open(): dc0. flag.  This flag effect applies only to the data
     range written by the system call.

     *note Availability: 1ef7.: Linux >= 4.7.

     Added in version 3.7.

 -- Data: os.RWF_SYNC

     Provide a per-write equivalent of the *note O_SYNC: 2d4a. *note
     os.open(): dc0. flag.  This flag effect applies only to the data
     range written by the system call.

     *note Availability: 1ef7.: Linux >= 4.7.

     Added in version 3.7.

 -- Data: os.RWF_APPEND

     Provide a per-write equivalent of the *note O_APPEND: 2d45. *note
     os.open(): dc0. flag.  This flag is meaningful only for *note
     os.pwritev(): b7c, and its effect applies only to the data range
     written by the system call.  The 'offset' argument does not affect
     the write operation; the data is always appended to the end of the
     file.  However, if the 'offset' argument is ‘-1’, the current file
     'offset' is updated.

     *note Availability: 1ef7.: Linux >= 4.16.

     Added in version 3.10.

 -- Function: os.read (fd, n, /)

     Read at most 'n' bytes from file descriptor 'fd'.

     Return a bytestring containing the bytes read.  If the end of the
     file referred to by 'fd' has been reached, an empty bytes object is
     returned.

          Note: This function is intended for low-level I/O and must be
          applied to a file descriptor as returned by *note os.open():
          dc0. or *note pipe(): 190a.  To read a “file object” returned
          by the built-in function *note open(): 51f. or by *note
          popen(): a96. or *note fdopen(): 20e3, or *note sys.stdin:
          540, use its *note read(): 1e24. or *note readline(): 1373.
          methods.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the function now
     retries the system call instead of raising an *note
     InterruptedError: db6. exception (see PEP 475(4) for the
     rationale).

 -- Function: os.sendfile (out_fd, in_fd, offset, count)

 -- Function: os.sendfile (out_fd, in_fd, offset, count, headers=(),
          trailers=(), flags=0)

     Copy 'count' bytes from file descriptor 'in_fd' to file descriptor
     'out_fd' starting at 'offset'.  Return the number of bytes sent.
     When EOF is reached return ‘0’.

     The first function notation is supported by all platforms that
     define ‘sendfile()’.

     On Linux, if 'offset' is given as ‘None’, the bytes are read from
     the current position of 'in_fd' and the position of 'in_fd' is
     updated.

     The second case may be used on macOS and FreeBSD where 'headers'
     and 'trailers' are arbitrary sequences of buffers that are written
     before and after the data from 'in_fd' is written.  It returns the
     same as the first case.

     On macOS and FreeBSD, a value of ‘0’ for 'count' specifies to send
     until the end of 'in_fd' is reached.

     All platforms support sockets as 'out_fd' file descriptor, and some
     platforms allow other types (e.g.  regular file, pipe) as well.

     Cross-platform applications should not use 'headers', 'trailers'
     and 'flags' arguments.

     *note Availability: 1ef7.: Unix, not WASI.

          Note: For a higher-level wrapper of ‘sendfile()’, see *note
          socket.socket.sendfile(): e91.

     Added in version 3.3.

     Changed in version 3.9: Parameters 'out' and 'in' was renamed to
     'out_fd' and 'in_fd'.

 -- Data: os.SF_NODISKIO
 -- Data: os.SF_MNOWAIT
 -- Data: os.SF_SYNC

     Parameters to the *note sendfile(): b28. function, if the
     implementation supports them.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.3.

 -- Data: os.SF_NOCACHE

     Parameter to the *note sendfile(): b28. function, if the
     implementation supports it.  The data won’t be cached in the
     virtual memory and will be freed afterwards.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.11.

 -- Function: os.set_blocking (fd, blocking, /)

     Set the blocking mode of the specified file descriptor.  Set the
     *note O_NONBLOCK: e6e. flag if blocking is ‘False’, clear the flag
     otherwise.

     See also *note get_blocking(): e6c. and *note
     socket.socket.setblocking(): 2d3a.

     *note Availability: 1ef7.: Unix, Windows.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

     On Windows, this function is limited to pipes.

     Added in version 3.5.

     Changed in version 3.12: Added support for pipes on Windows.

 -- Function: os.splice (src, dst, count, offset_src=None,
          offset_dst=None)

     Transfer 'count' bytes from file descriptor 'src', starting from
     offset 'offset_src', to file descriptor 'dst', starting from offset
     'offset_dst'.  At least one of the file descriptors must refer to a
     pipe.  If 'offset_src' is ‘None’, then 'src' is read from the
     current position; respectively for 'offset_dst'.  The offset
     associated to the file descriptor that refers to a pipe must be
     ‘None’.  The files pointed to by 'src' and 'dst' must reside in the
     same filesystem, otherwise an *note OSError: 41a. is raised with
     *note errno: 15fa. set to *note errno.EXDEV: 2d38.

     This copy is done without the additional cost of transferring data
     from the kernel to user space and then back into the kernel.
     Additionally, some filesystems could implement extra optimizations.
     The copy is done as if both files are opened as binary.

     Upon successful completion, returns the number of bytes spliced to
     or from the pipe.  A return value of 0 means end of input.  If
     'src' refers to a pipe, then this means that there was no data to
     transfer, and it would not make sense to block because there are no
     writers connected to the write end of the pipe.

     *note Availability: 1ef7.: Linux >= 2.6.17 with glibc >= 2.5

     Added in version 3.10.

 -- Data: os.SPLICE_F_MOVE
 -- Data: os.SPLICE_F_NONBLOCK
 -- Data: os.SPLICE_F_MORE

     Added in version 3.10.

 -- Function: os.readv (fd, buffers, /)

     Read from a file descriptor 'fd' into a number of mutable *note
     bytes-like objects: d55. 'buffers'.  Transfer data into each buffer
     until it is full and then move on to the next buffer in the
     sequence to hold the rest of the data.

     Return the total number of bytes actually read which can be less
     than the total capacity of all the objects.

     The operating system may set a limit (*note sysconf(): 1670. value
     ‘'SC_IOV_MAX'’) on the number of buffers that can be used.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.tcgetpgrp (fd, /)

     Return the process group associated with the terminal given by 'fd'
     (an open file descriptor as returned by *note os.open(): dc0.).

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.tcsetpgrp (fd, pg, /)

     Set the process group associated with the terminal given by 'fd'
     (an open file descriptor as returned by *note os.open(): dc0.) to
     'pg'.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.ttyname (fd, /)

     Return a string which specifies the terminal device associated with
     file descriptor 'fd'.  If 'fd' is not associated with a terminal
     device, an exception is raised.

     *note Availability: 1ef7.: Unix.

 -- Function: os.unlockpt (fd, /)

     Unlock the slave pseudo-terminal device associated with the master
     pseudo-terminal device to which the file descriptor 'fd' refers.
     The file descriptor 'fd' is not closed upon failure.

     Calls the C standard library function ‘unlockpt()’.

     *note Availability: 1ef7.: Unix, not WASI.

     Added in version 3.13.

 -- Function: os.write (fd, str, /)

     Write the bytestring in 'str' to file descriptor 'fd'.

     Return the number of bytes actually written.

          Note: This function is intended for low-level I/O and must be
          applied to a file descriptor as returned by *note os.open():
          dc0. or *note pipe(): 190a.  To write a “file object” returned
          by the built-in function *note open(): 51f. or by *note
          popen(): a96. or *note fdopen(): 20e3, or *note sys.stdout:
          aec. or *note sys.stderr: 943, use its *note write(): 1e13.
          method.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the function now
     retries the system call instead of raising an *note
     InterruptedError: db6. exception (see PEP 475(5) for the
     rationale).

 -- Function: os.writev (fd, buffers, /)

     Write the contents of 'buffers' to file descriptor 'fd'.  'buffers'
     must be a sequence of *note bytes-like objects: d55.  Buffers are
     processed in array order.  Entire contents of the first buffer is
     written before proceeding to the second, and so on.

     Returns the total number of bytes actually written.

     The operating system may set a limit (*note sysconf(): 1670. value
     ‘'SC_IOV_MAX'’) on the number of buffers that can be used.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

* Menu:

* Querying the size of a terminal::
* Inheritance of File Descriptors::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://manpages.debian.org/open(2)

   (3) https://msdn.microsoft.com/en-us/library/z0kc8e3z.aspx

   (4) https://peps.python.org/pep-0475/

   (5) https://peps.python.org/pep-0475/


File: python.info,  Node: Querying the size of a terminal,  Next: Inheritance of File Descriptors,  Up: File Descriptor Operations

5.16.1.6 Querying the size of a terminal
........................................

Added in version 3.3.

 -- Function: os.get_terminal_size (fd=STDOUT_FILENO, /)

     Return the size of the terminal window as ‘(columns, lines)’, tuple
     of type *note terminal_size: 2a50.

     The optional argument ‘fd’ (default ‘STDOUT_FILENO’, or standard
     output) specifies which file descriptor should be queried.

     If the file descriptor is not connected to a terminal, an *note
     OSError: 41a. is raised.

     *note shutil.get_terminal_size(): 1147. is the high-level function
     which should normally be used, ‘os.get_terminal_size’ is the
     low-level implementation.

     *note Availability: 1ef7.: Unix, Windows.

 -- Class: os.terminal_size

     A subclass of tuple, holding ‘(columns, lines)’ of the terminal
     window size.

      -- Attribute: columns

          Width of the terminal window in characters.

      -- Attribute: lines

          Height of the terminal window in characters.


File: python.info,  Node: Inheritance of File Descriptors,  Prev: Querying the size of a terminal,  Up: File Descriptor Operations

5.16.1.7 Inheritance of File Descriptors
........................................

Added in version 3.4.

A file descriptor has an “inheritable” flag which indicates if the file
descriptor can be inherited by child processes.  Since Python 3.4, file
descriptors created by Python are non-inheritable by default.

On UNIX, non-inheritable file descriptors are closed in child processes
at the execution of a new program, other file descriptors are inherited.
Note that non-inheritable file descriptors are still 'inherited' by
child processes on *note os.fork(): 197.

On Windows, non-inheritable handles and file descriptors are closed in
child processes, except for standard streams (file descriptors 0, 1 and
2: stdin, stdout and stderr), which are always inherited.  Using *note
spawn*: 1842. functions, all inheritable handles and all inheritable
file descriptors are inherited.  Using the *note subprocess: d6. module,
all file descriptors except standard streams are closed, and inheritable
handles are only inherited if the 'close_fds' parameter is ‘False’.

On WebAssembly platforms, the file descriptor cannot be modified.

 -- Function: os.get_inheritable (fd, /)

     Get the “inheritable” flag of the specified file descriptor (a
     boolean).

 -- Function: os.set_inheritable (fd, inheritable, /)

     Set the “inheritable” flag of the specified file descriptor.

 -- Function: os.get_handle_inheritable (handle, /)

     Get the “inheritable” flag of the specified handle (a boolean).

     *note Availability: 1ef7.: Windows.

 -- Function: os.set_handle_inheritable (handle, inheritable, /)

     Set the “inheritable” flag of the specified handle.

     *note Availability: 1ef7.: Windows.


File: python.info,  Node: Files and Directories,  Next: Process Management,  Prev: File Descriptor Operations,  Up: os — Miscellaneous operating system interfaces

5.16.1.8 Files and Directories
..............................

On some Unix platforms, many of these functions support one or more of
these features:

   * 'specifying a file descriptor:' Normally the 'path' argument
     provided to functions in the ‘os’ module must be a string
     specifying a file path.  However, some functions now alternatively
     accept an open file descriptor for their 'path' argument.  The
     function will then operate on the file referred to by the
     descriptor.  For POSIX systems, Python will call the variant of the
     function prefixed with ‘f’ (e.g.  call ‘fchdir’ instead of
     ‘chdir’).

     You can check whether or not 'path' can be specified as a file
     descriptor for a particular function on your platform using *note
     os.supports_fd: 1141.  If this functionality is unavailable, using
     it will raise a *note NotImplementedError: 228.

     If the function also supports 'dir_fd' or 'follow_symlinks'
     arguments, it’s an error to specify one of those when supplying
     'path' as a file descriptor.

   * 'paths relative to directory descriptors:' If 'dir_fd' is not
     ‘None’, it should be a file descriptor referring to a directory,
     and the path to operate on should be relative; path will then be
     relative to that directory.  If the path is absolute, 'dir_fd' is
     ignored.  For POSIX systems, Python will call the variant of the
     function with an ‘at’ suffix and possibly prefixed with ‘f’ (e.g.
     call ‘faccessat’ instead of ‘access’).

     You can check whether or not 'dir_fd' is supported for a particular
     function on your platform using *note os.supports_dir_fd: 113b.  If
     it’s unavailable, using it will raise a *note NotImplementedError:
     228.

   * 'not following symlinks:' If 'follow_symlinks' is ‘False’, and the
     last element of the path to operate on is a symbolic link, the
     function will operate on the symbolic link itself rather than the
     file pointed to by the link.  For POSIX systems, Python will call
     the ‘l...’ variant of the function.

     You can check whether or not 'follow_symlinks' is supported for a
     particular function on your platform using *note
     os.supports_follow_symlinks: 113c.  If it’s unavailable, using it
     will raise a *note NotImplementedError: 228.

 -- Function: os.access (path, mode, *, dir_fd=None,
          effective_ids=False, follow_symlinks=True)

     Use the real uid/gid to test for access to 'path'.  Note that most
     operations will use the effective uid/gid, therefore this routine
     can be used in a suid/sgid environment to test if the invoking user
     has the specified access to 'path'.  'mode' should be *note F_OK:
     2d73. to test the existence of 'path', or it can be the inclusive
     OR of one or more of *note R_OK: 2d74, *note W_OK: 2d75, and *note
     X_OK: 2d76. to test permissions.  Return *note True: c2d. if access
     is allowed, *note False: b4f. if not.  See the Unix man page
     ‘access(2)(1)’ for more information.

     This function can support specifying *note paths relative to
     directory descriptors: 112e. and *note not following symlinks:
     112f.

     If 'effective_ids' is ‘True’, ‘access()’ will perform its access
     checks using the effective uid/gid instead of the real uid/gid.
     'effective_ids' may not be supported on your platform; you can
     check whether or not it is available using *note
     os.supports_effective_ids: 1142.  If it is unavailable, using it
     will raise a *note NotImplementedError: 228.

          Note: Using ‘access()’ to check if a user is authorized to
          e.g.  open a file before actually doing so using *note open():
          51f. creates a security hole, because the user might exploit
          the short time interval between checking and opening the file
          to manipulate it.  It’s preferable to use *note EAFP: 2d77.
          techniques.  For example:

               if os.access("myfile", os.R_OK):
                   with open("myfile") as fp:
                       return fp.read()
               return "some default data"

          is better written as:

               try:
                   fp = open("myfile")
               except PermissionError:
                   return "some default data"
               else:
                   with fp:
                       return fp.read()

          Note: I/O operations may fail even when ‘access()’ indicates
          that they would succeed, particularly for operations on
          network filesystems which may have permissions semantics
          beyond the usual POSIX permission-bit model.

     Changed in version 3.3: Added the 'dir_fd', 'effective_ids', and
     'follow_symlinks' parameters.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Data: os.F_OK
 -- Data: os.R_OK
 -- Data: os.W_OK
 -- Data: os.X_OK

     Values to pass as the 'mode' parameter of *note access(): 1130. to
     test the existence, readability, writability and executability of
     'path', respectively.

 -- Function: os.chdir (path)

     Change the current working directory to 'path'.

     This function can support *note specifying a file descriptor: b78.
     The descriptor must refer to an opened directory, not an open file.

     This function can raise *note OSError: 41a. and subclasses such as
     *note FileNotFoundError: 42e, *note PermissionError: d6b, and *note
     NotADirectoryError: 1098.

     Raises an *note auditing event: 1a15. ‘os.chdir’ with argument
     ‘path’.

     Changed in version 3.3: Added support for specifying 'path' as a
     file descriptor on some platforms.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.chflags (path, flags, *, follow_symlinks=True)

     Set the flags of 'path' to the numeric 'flags'.  'flags' may take a
     combination (bitwise OR) of the following values (as defined in the
     *note stat: d1. module):

        * *note stat.UF_NODUMP: 29de.

        * *note stat.UF_IMMUTABLE: 29df.

        * *note stat.UF_APPEND: 29e0.

        * *note stat.UF_OPAQUE: 29e1.

        * *note stat.UF_NOUNLINK: 29e2.

        * *note stat.UF_COMPRESSED: 29e3.

        * *note stat.UF_HIDDEN: 29e6.

        * *note stat.SF_ARCHIVED: 29ea.

        * *note stat.SF_IMMUTABLE: 29eb.

        * *note stat.SF_APPEND: 29ec.

        * *note stat.SF_NOUNLINK: 29ee.

        * *note stat.SF_SNAPSHOT: 29ef.

     This function can support *note not following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.chflags’ with arguments
     ‘path’, ‘flags’.

     *note Availability: 1ef7.: Unix, not WASI.

     Changed in version 3.3: Added the 'follow_symlinks' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.chmod (path, mode, *, dir_fd=None,
          follow_symlinks=True)

     Change the mode of 'path' to the numeric 'mode'.  'mode' may take
     one of the following values (as defined in the *note stat: d1.
     module) or bitwise ORed combinations of them:

        * *note stat.S_ISUID: 29ca.

        * *note stat.S_ISGID: 29cb.

        * *note stat.S_ENFMT: 29cd.

        * *note stat.S_ISVTX: 29ce.

        * *note stat.S_IREAD: 29da.

        * *note stat.S_IWRITE: 29db.

        * *note stat.S_IEXEC: 29dc.

        * *note stat.S_IRWXU: 29cf.

        * *note stat.S_IRUSR: 29d0.

        * *note stat.S_IWUSR: 29d1.

        * *note stat.S_IXUSR: 29d2.

        * *note stat.S_IRWXG: 29d3.

        * *note stat.S_IRGRP: 29d4.

        * *note stat.S_IWGRP: 29d5.

        * *note stat.S_IXGRP: 29cc.

        * *note stat.S_IRWXO: 29d6.

        * *note stat.S_IROTH: 29d7.

        * *note stat.S_IWOTH: 29d8.

        * *note stat.S_IXOTH: 29d9.

     This function can support *note specifying a file descriptor: b78,
     *note paths relative to directory descriptors: 112e. and *note not
     following symlinks: 112f.

          Note: Although Windows supports ‘chmod()’, you can only set
          the file’s read-only flag with it (via the ‘stat.S_IWRITE’ and
          ‘stat.S_IREAD’ constants or a corresponding integer value).
          All other bits are ignored.  The default value of
          'follow_symlinks' is ‘False’ on Windows.

          The function is limited on WASI, see *note WebAssembly
          platforms: 1910. for more information.

     Raises an *note auditing event: 1a15. ‘os.chmod’ with arguments
     ‘path’, ‘mode’, ‘dir_fd’.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor, and the 'dir_fd' and 'follow_symlinks'
     arguments.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.13: Added support for a file descriptor and
     the 'follow_symlinks' argument on Windows.

 -- Function: os.chown (path, uid, gid, *, dir_fd=None,
          follow_symlinks=True)

     Change the owner and group id of 'path' to the numeric 'uid' and
     'gid'.  To leave one of the ids unchanged, set it to -1.

     This function can support *note specifying a file descriptor: b78,
     *note paths relative to directory descriptors: 112e. and *note not
     following symlinks: 112f.

     See *note shutil.chown(): 240. for a higher-level function that
     accepts names in addition to numeric ids.

     Raises an *note auditing event: 1a15. ‘os.chown’ with arguments
     ‘path’, ‘uid’, ‘gid’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor, and the 'dir_fd' and 'follow_symlinks'
     arguments.

     Changed in version 3.6: Supports a *note path-like object: 2a0.

 -- Function: os.chroot (path)

     Change the root directory of the current process to 'path'.

     *note Availability: 1ef7.: Unix, not WASI, not Android.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.fchdir (fd)

     Change the current working directory to the directory represented
     by the file descriptor 'fd'.  The descriptor must refer to an
     opened directory, not an open file.  As of Python 3.3, this is
     equivalent to ‘os.chdir(fd)’.

     Raises an *note auditing event: 1a15. ‘os.chdir’ with argument
     ‘path’.

     *note Availability: 1ef7.: Unix.

 -- Function: os.getcwd ()

     Return a string representing the current working directory.

 -- Function: os.getcwdb ()

     Return a bytestring representing the current working directory.

     Changed in version 3.8: The function now uses the UTF-8 encoding on
     Windows, rather than the ANSI code page: see PEP 529(2) for the
     rationale.  The function is no longer deprecated on Windows.

 -- Function: os.lchflags (path, flags)

     Set the flags of 'path' to the numeric 'flags', like *note
     chflags(): 1131, but do not follow symbolic links.  As of Python
     3.3, this is equivalent to ‘os.chflags(path, flags,
     follow_symlinks=False)’.

     Raises an *note auditing event: 1a15. ‘os.chflags’ with arguments
     ‘path’, ‘flags’.

     *note Availability: 1ef7.: Unix, not WASI.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.lchmod (path, mode)

     Change the mode of 'path' to the numeric 'mode'.  If path is a
     symlink, this affects the symlink rather than the target.  See the
     docs for *note chmod(): 21b. for possible values of 'mode'.  As of
     Python 3.3, this is equivalent to ‘os.chmod(path, mode,
     follow_symlinks=False)’.

     ‘lchmod()’ is not part of POSIX, but Unix implementations may have
     it if changing the mode of symbolic links is supported.

     Raises an *note auditing event: 1a15. ‘os.chmod’ with arguments
     ‘path’, ‘mode’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix, Windows, not Linux, FreeBSD >=
     1.3, NetBSD >= 1.3, not OpenBSD

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.13: Added support on Windows.

 -- Function: os.lchown (path, uid, gid)

     Change the owner and group id of 'path' to the numeric 'uid' and
     'gid'.  This function will not follow symbolic links.  As of Python
     3.3, this is equivalent to ‘os.chown(path, uid, gid,
     follow_symlinks=False)’.

     Raises an *note auditing event: 1a15. ‘os.chown’ with arguments
     ‘path’, ‘uid’, ‘gid’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.link (src, dst, *, src_dir_fd=None, dst_dir_fd=None,
          follow_symlinks=True)

     Create a hard link pointing to 'src' named 'dst'.

     This function can support specifying 'src_dir_fd' and/or
     'dst_dir_fd' to supply *note paths relative to directory
     descriptors: 112e, and *note not following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.link’ with arguments
     ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.2: Added Windows support.

     Changed in version 3.3: Added the 'src_dir_fd', 'dst_dir_fd', and
     'follow_symlinks' parameters.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'src' and 'dst'.

 -- Function: os.listdir (path='.')

     Return a list containing the names of the entries in the directory
     given by 'path'.  The list is in arbitrary order, and does not
     include the special entries ‘'.'’ and ‘'..'’ even if they are
     present in the directory.  If a file is removed from or added to
     the directory during the call of this function, whether a name for
     that file be included is unspecified.

     'path' may be a *note path-like object: 2a0.  If 'path' is of type
     ‘bytes’ (directly or indirectly through the *note PathLike: c72.
     interface), the filenames returned will also be of type ‘bytes’; in
     all other circumstances, they will be of type ‘str’.

     This function can also support *note specifying a file descriptor:
     b78.; the file descriptor must refer to a directory.

     Raises an *note auditing event: 1a15. ‘os.listdir’ with argument
     ‘path’.

          Note: To encode ‘str’ filenames to ‘bytes’, use *note
          fsencode(): c76.

     See also
     ........

     The *note scandir(): a6d. function returns directory entries along
     with file attribute information, giving better performance for many
     common use cases.

     Changed in version 3.2: The 'path' parameter became optional.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.listdrives ()

     Return a list containing the names of drives on a Windows system.

     A drive name typically looks like ‘'C:\\'’.  Not every drive name
     will be associated with a volume, and some may be inaccessible for
     a variety of reasons, including permissions, network connectivity
     or missing media.  This function does not test for access.

     May raise *note OSError: 41a. if an error occurs collecting the
     drive names.

     Raises an *note auditing event: 1a15. ‘os.listdrives’ with no
     arguments.

     *note Availability: 1ef7.: Windows

     Added in version 3.12.

 -- Function: os.listmounts (volume)

     Return a list containing the mount points for a volume on a Windows
     system.

     'volume' must be represented as a GUID path, like those returned by
     *note os.listvolumes(): 4a1.  Volumes may be mounted in multiple
     locations or not at all.  In the latter case, the list will be
     empty.  Mount points that are not associated with a volume will not
     be returned by this function.

     The mount points return by this function will be absolute paths,
     and may be longer than the drive name.

     Raises *note OSError: 41a. if the volume is not recognized or if an
     error occurs collecting the paths.

     Raises an *note auditing event: 1a15. ‘os.listmounts’ with argument
     ‘volume’.

     *note Availability: 1ef7.: Windows

     Added in version 3.12.

 -- Function: os.listvolumes ()

     Return a list containing the volumes in the system.

     Volumes are typically represented as a GUID path that looks like
     ‘\\?\Volume{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}\’.  Files can
     usually be accessed through a GUID path, permissions allowing.
     However, users are generally not familiar with them, and so the
     recommended use of this function is to retrieve mount points using
     *note os.listmounts(): 4a2.

     May raise *note OSError: 41a. if an error occurs collecting the
     volumes.

     Raises an *note auditing event: 1a15. ‘os.listvolumes’ with no
     arguments.

     *note Availability: 1ef7.: Windows

     Added in version 3.12.

 -- Function: os.lstat (path, *, dir_fd=None)

     Perform the equivalent of an ‘lstat()’ system call on the given
     path.  Similar to *note stat(): 4a3, but does not follow symbolic
     links.  Return a *note stat_result: 1510. object.

     On platforms that do not support symbolic links, this is an alias
     for *note stat(): 4a3.

     As of Python 3.3, this is equivalent to ‘os.stat(path,
     dir_fd=dir_fd, follow_symlinks=False)’.

     This function can also support *note paths relative to directory
     descriptors: 112e.

     See also
     ........

     The *note stat(): 4a3. function.

     Changed in version 3.2: Added support for Windows 6.0 (Vista)
     symbolic links.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.8: On Windows, now opens reparse points that
     represent another path (name surrogates), including symbolic links
     and directory junctions.  Other kinds of reparse points are
     resolved by the operating system as for *note stat(): 4a3.

 -- Function: os.mkdir (path, mode=0o777, *, dir_fd=None)

     Create a directory named 'path' with numeric mode 'mode'.

     If the directory already exists, *note FileExistsError: 105b. is
     raised.  If a parent directory in the path does not exist, *note
     FileNotFoundError: 42e. is raised.  On some systems, 'mode' is
     ignored.  Where it is used, the current umask value is first masked
     out.  If bits other than the last 9 (i.e.  the last 3 digits of the
     octal representation of the 'mode') are set, their meaning is
     platform-dependent.  On some platforms, they are ignored and you
     should call *note chmod(): 21b. explicitly to set them.

     On Windows, a 'mode' of ‘0o700’ is specifically handled to apply
     access control to the new directory such that only the current user
     and administrators have access.  Other values of 'mode' are
     ignored.

     This function can also support *note paths relative to directory
     descriptors: 112e.

     It is also possible to create temporary directories; see the *note
     tempfile: e0. module’s *note tempfile.mkdtemp(): 21f. function.

     Raises an *note auditing event: 1a15. ‘os.mkdir’ with arguments
     ‘path’, ‘mode’, ‘dir_fd’.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.13: Windows now handles a 'mode' of ‘0o700’.

 -- Function: os.makedirs (name, mode=0o777, exist_ok=False)

     Recursive directory creation function.  Like *note mkdir(): 21d,
     but makes all intermediate-level directories needed to contain the
     leaf directory.

     The 'mode' parameter is passed to *note mkdir(): 21d. for creating
     the leaf directory; see *note the mkdir() description: 2d7a. for
     how it is interpreted.  To set the file permission bits of any
     newly created parent directories you can set the umask before
     invoking ‘makedirs()’.  The file permission bits of existing parent
     directories are not changed.

     If 'exist_ok' is ‘False’ (the default), a *note FileExistsError:
     105b. is raised if the target directory already exists.

          Note: ‘makedirs()’ will become confused if the path elements
          to create include *note pardir: 2d7b. (eg.  “..” on UNIX
          systems).

     This function handles UNC paths correctly.

     Raises an *note auditing event: 1a15. ‘os.mkdir’ with arguments
     ‘path’, ‘mode’, ‘dir_fd’.

     Changed in version 3.2: Added the 'exist_ok' parameter.

     Changed in version 3.4.1: Before Python 3.4.1, if 'exist_ok' was
     ‘True’ and the directory existed, ‘makedirs()’ would still raise an
     error if 'mode' did not match the mode of the existing directory.
     Since this behavior was impossible to implement safely, it was
     removed in Python 3.4.1.  See bpo-21082(3).

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.7: The 'mode' argument no longer affects the
     file permission bits of newly created intermediate-level
     directories.

 -- Function: os.mkfifo (path, mode=0o666, *, dir_fd=None)

     Create a FIFO (a named pipe) named 'path' with numeric mode 'mode'.
     The current umask value is first masked out from the mode.

     This function can also support *note paths relative to directory
     descriptors: 112e.

     FIFOs are pipes that can be accessed like regular files.  FIFOs
     exist until they are deleted (for example with *note os.unlink():
     1139.).  Generally, FIFOs are used as rendezvous between “client”
     and “server” type processes: the server opens the FIFO for reading,
     and the client opens it for writing.  Note that ‘mkfifo()’ doesn’t
     open the FIFO — it just creates the rendezvous point.

     *note Availability: 1ef7.: Unix, not WASI.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.mknod (path, mode=0o600, device=0, *, dir_fd=None)

     Create a filesystem node (file, device special file or named pipe)
     named 'path'.  'mode' specifies both the permissions to use and the
     type of node to be created, being combined (bitwise OR) with one of
     ‘stat.S_IFREG’, ‘stat.S_IFCHR’, ‘stat.S_IFBLK’, and ‘stat.S_IFIFO’
     (those constants are available in *note stat: d1.).  For
     ‘stat.S_IFCHR’ and ‘stat.S_IFBLK’, 'device' defines the newly
     created device special file (probably using *note os.makedev():
     1724.), otherwise it is ignored.

     This function can also support *note paths relative to directory
     descriptors: 112e.

     *note Availability: 1ef7.: Unix, not WASI.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.major (device, /)

     Extract the device major number from a raw device number (usually
     the ‘st_dev’ or ‘st_rdev’ field from ‘stat’).

 -- Function: os.minor (device, /)

     Extract the device minor number from a raw device number (usually
     the ‘st_dev’ or ‘st_rdev’ field from ‘stat’).

 -- Function: os.makedev (major, minor, /)

     Compose a raw device number from the major and minor device
     numbers.

 -- Function: os.pathconf (path, name)

     Return system configuration information relevant to a named file.
     'name' specifies the configuration value to retrieve; it may be a
     string which is the name of a defined system value; these names are
     specified in a number of standards (POSIX.1, Unix 95, Unix 98, and
     others).  Some platforms define additional names as well.  The
     names known to the host operating system are given in the
     ‘pathconf_names’ dictionary.  For configuration variables not
     included in that mapping, passing an integer for 'name' is also
     accepted.

     If 'name' is a string and is not known, *note ValueError: 202. is
     raised.  If a specific value for 'name' is not supported by the
     host system, even if it is included in ‘pathconf_names’, an *note
     OSError: 41a. is raised with *note errno.EINVAL: 1b7f. for the
     error number.

     This function can support *note specifying a file descriptor: b78.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Data: os.pathconf_names

     Dictionary mapping names accepted by *note pathconf(): 113f. and
     *note fpathconf(): 2d39. to the integer values defined for those
     names by the host operating system.  This can be used to determine
     the set of names known to the system.

     *note Availability: 1ef7.: Unix.

 -- Function: os.readlink (path, *, dir_fd=None)

     Return a string representing the path to which the symbolic link
     points.  The result may be either an absolute or relative pathname;
     if it is relative, it may be converted to an absolute pathname
     using ‘os.path.join(os.path.dirname(path), result)’.

     If the 'path' is a string object (directly or indirectly through a
     *note PathLike: c72. interface), the result will also be a string
     object, and the call may raise a UnicodeDecodeError.  If the 'path'
     is a bytes object (direct or indirectly), the result will be a
     bytes object.

     This function can also support *note paths relative to directory
     descriptors: 112e.

     When trying to resolve a path that may contain links, use *note
     realpath(): 225. to properly handle recursion and platform
     differences.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.2: Added support for Windows 6.0 (Vista)
     symbolic links.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. on
     Unix.

     Changed in version 3.8: Accepts a *note path-like object: 2a0. and
     a bytes object on Windows.

     Added support for directory junctions, and changed to return the
     substitution path (which typically includes ‘\\?\’ prefix) rather
     than the optional “print name” field that was previously returned.

 -- Function: os.remove (path, *, dir_fd=None)

     Remove (delete) the file 'path'.  If 'path' is a directory, an
     *note OSError: 41a. is raised.  Use *note rmdir(): 1137. to remove
     directories.  If the file does not exist, a *note
     FileNotFoundError: 42e. is raised.

     This function can support *note paths relative to directory
     descriptors: 112e.

     On Windows, attempting to remove a file that is in use causes an
     exception to be raised; on Unix, the directory entry is removed but
     the storage allocated to the file is not made available until the
     original file is no longer in use.

     This function is semantically identical to *note unlink(): 1139.

     Raises an *note auditing event: 1a15. ‘os.remove’ with arguments
     ‘path’, ‘dir_fd’.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.removedirs (name)

     Remove directories recursively.  Works like *note rmdir(): 1137.
     except that, if the leaf directory is successfully removed,
     ‘removedirs()’ tries to successively remove every parent directory
     mentioned in 'path' until an error is raised (which is ignored,
     because it generally means that a parent directory is not empty).
     For example, ‘os.removedirs('foo/bar/baz')’ will first remove the
     directory ‘'foo/bar/baz'’, and then remove ‘'foo/bar'’ and ‘'foo'’
     if they are empty.  Raises *note OSError: 41a. if the leaf
     directory could not be successfully removed.

     Raises an *note auditing event: 1a15. ‘os.remove’ with arguments
     ‘path’, ‘dir_fd’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.rename (src, dst, *, src_dir_fd=None, dst_dir_fd=None)

     Rename the file or directory 'src' to 'dst'.  If 'dst' exists, the
     operation will fail with an *note OSError: 41a. subclass in a
     number of cases:

     On Windows, if 'dst' exists a *note FileExistsError: 105b. is
     always raised.  The operation may fail if 'src' and 'dst' are on
     different filesystems.  Use *note shutil.move(): a6a. to support
     moves to a different filesystem.

     On Unix, if 'src' is a file and 'dst' is a directory or vice-versa,
     an *note IsADirectoryError: 1097. or a *note NotADirectoryError:
     1098. will be raised respectively.  If both are directories and
     'dst' is empty, 'dst' will be silently replaced.  If 'dst' is a
     non-empty directory, an *note OSError: 41a. is raised.  If both are
     files, 'dst' will be replaced silently if the user has permission.
     The operation may fail on some Unix flavors if 'src' and 'dst' are
     on different filesystems.  If successful, the renaming will be an
     atomic operation (this is a POSIX requirement).

     This function can support specifying 'src_dir_fd' and/or
     'dst_dir_fd' to supply *note paths relative to directory
     descriptors: 112e.

     If you want cross-platform overwriting of the destination, use
     *note replace(): 1136.

     Raises an *note auditing event: 1a15. ‘os.rename’ with arguments
     ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’.

     Changed in version 3.3: Added the 'src_dir_fd' and 'dst_dir_fd'
     parameters.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'src' and 'dst'.

 -- Function: os.renames (old, new)

     Recursive directory or file renaming function.  Works like *note
     rename(): 1135, except creation of any intermediate directories
     needed to make the new pathname good is attempted first.  After the
     rename, directories corresponding to rightmost path segments of the
     old name will be pruned away using *note removedirs(): 2d7d.

          Note: This function can fail with the new directory structure
          made if you lack permissions needed to remove the leaf
          directory or file.

     Raises an *note auditing event: 1a15. ‘os.rename’ with arguments
     ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'old' and 'new'.

 -- Function: os.replace (src, dst, *, src_dir_fd=None, dst_dir_fd=None)

     Rename the file or directory 'src' to 'dst'.  If 'dst' is a
     non-empty directory, *note OSError: 41a. will be raised.  If 'dst'
     exists and is a file, it will be replaced silently if the user has
     permission.  The operation may fail if 'src' and 'dst' are on
     different filesystems.  If successful, the renaming will be an
     atomic operation (this is a POSIX requirement).

     This function can support specifying 'src_dir_fd' and/or
     'dst_dir_fd' to supply *note paths relative to directory
     descriptors: 112e.

     Raises an *note auditing event: 1a15. ‘os.rename’ with arguments
     ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’.

     Added in version 3.3.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'src' and 'dst'.

 -- Function: os.rmdir (path, *, dir_fd=None)

     Remove (delete) the directory 'path'.  If the directory does not
     exist or is not empty, a *note FileNotFoundError: 42e. or an *note
     OSError: 41a. is raised respectively.  In order to remove whole
     directory trees, *note shutil.rmtree(): 301. can be used.

     This function can support *note paths relative to directory
     descriptors: 112e.

     Raises an *note auditing event: 1a15. ‘os.rmdir’ with arguments
     ‘path’, ‘dir_fd’.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.scandir (path='.')

     Return an iterator of *note os.DirEntry: 49e. objects corresponding
     to the entries in the directory given by 'path'.  The entries are
     yielded in arbitrary order, and the special entries ‘'.'’ and
     ‘'..'’ are not included.  If a file is removed from or added to the
     directory after creating the iterator, whether an entry for that
     file be included is unspecified.

     Using ‘scandir()’ instead of *note listdir(): 113e. can
     significantly increase the performance of code that also needs file
     type or file attribute information, because *note os.DirEntry: 49e.
     objects expose this information if the operating system provides it
     when scanning a directory.  All ‘os.DirEntry’ methods may perform a
     system call, but *note is_dir(): 2d7f. and *note is_file(): db2.
     usually only require a system call for symbolic links; *note
     os.DirEntry.stat(): 180a. always requires a system call on Unix but
     only requires one for symbolic links on Windows.

     'path' may be a *note path-like object: 2a0.  If 'path' is of type
     ‘bytes’ (directly or indirectly through the *note PathLike: c72.
     interface), the type of the *note name: 2d80. and *note path: 178f.
     attributes of each *note os.DirEntry: 49e. will be ‘bytes’; in all
     other circumstances, they will be of type ‘str’.

     This function can also support *note specifying a file descriptor:
     b78.; the file descriptor must refer to a directory.

     Raises an *note auditing event: 1a15. ‘os.scandir’ with argument
     ‘path’.

     The ‘scandir()’ iterator supports the *note context manager: 5d7.
     protocol and has the following method:

      -- Method: scandir.close ()

          Close the iterator and free acquired resources.

          This is called automatically when the iterator is exhausted or
          garbage collected, or when an error happens during iterating.
          However it is advisable to call it explicitly or use the *note
          with: 5d5. statement.

          Added in version 3.6.

     The following example shows a simple use of ‘scandir()’ to display
     all the files (excluding directories) in the given 'path' that
     don’t start with ‘'.'’.  The ‘entry.is_file()’ call will generally
     not make an additional system call:

          with os.scandir(path) as it:
              for entry in it:
                  if not entry.name.startswith('.') and entry.is_file():
                      print(entry.name)

          Note: On Unix-based systems, ‘scandir()’ uses the system’s
          opendir()(4) and readdir()(5) functions.  On Windows, it uses
          the Win32 FindFirstFileW(6) and FindNextFileW(7) functions.

     Added in version 3.5.

     Changed in version 3.6: Added support for the *note context
     manager: 5d7. protocol and the *note close(): ce2. method.  If a
     ‘scandir()’ iterator is neither exhausted nor explicitly closed a
     *note ResourceWarning: 244. will be emitted in its destructor.

     The function accepts a *note path-like object: 2a0.

     Changed in version 3.7: Added support for *note file descriptors:
     b78. on Unix.

 -- Class: os.DirEntry

     Object yielded by *note scandir(): a6d. to expose the file path and
     other file attributes of a directory entry.

     *note scandir(): a6d. will provide as much of this information as
     possible without making additional system calls.  When a ‘stat()’
     or ‘lstat()’ system call is made, the ‘os.DirEntry’ object will
     cache the result.

     ‘os.DirEntry’ instances are not intended to be stored in long-lived
     data structures; if you know the file metadata has changed or if a
     long time has elapsed since calling *note scandir(): a6d, call
     ‘os.stat(entry.path)’ to fetch up-to-date information.

     Because the ‘os.DirEntry’ methods can make operating system calls,
     they may also raise *note OSError: 41a.  If you need very
     fine-grained control over errors, you can catch ‘OSError’ when
     calling one of the ‘os.DirEntry’ methods and handle as appropriate.

     To be directly usable as a *note path-like object: 2a0,
     ‘os.DirEntry’ implements the *note PathLike: c72. interface.

     Attributes and methods on a ‘os.DirEntry’ instance are as follows:

      -- Attribute: name

          The entry’s base filename, relative to the *note scandir():
          a6d. 'path' argument.

          The *note name: 2d00. attribute will be ‘bytes’ if the *note
          scandir(): a6d. 'path' argument is of type ‘bytes’ and ‘str’
          otherwise.  Use *note fsdecode(): c75. to decode byte
          filenames.

      -- Attribute: path

          The entry’s full path name: equivalent to
          ‘os.path.join(scandir_path, entry.name)’ where 'scandir_path'
          is the *note scandir(): a6d. 'path' argument.  The path is
          only absolute if the ‘scandir()’ 'path' argument was absolute.
          If the ‘scandir()’ 'path' argument was a *note file
          descriptor: b78, the *note path: a2. attribute is the same as
          the *note name: 2d00. attribute.

          The *note path: a2. attribute will be ‘bytes’ if the *note
          scandir(): a6d. 'path' argument is of type ‘bytes’ and ‘str’
          otherwise.  Use *note fsdecode(): c75. to decode byte
          filenames.

      -- Method: inode ()

          Return the inode number of the entry.

          The result is cached on the ‘os.DirEntry’ object.  Use
          ‘os.stat(entry.path, follow_symlinks=False).st_ino’ to fetch
          up-to-date information.

          On the first, uncached call, a system call is required on
          Windows but not on Unix.

      -- Method: is_dir (*, follow_symlinks=True)

          Return ‘True’ if this entry is a directory or a symbolic link
          pointing to a directory; return ‘False’ if the entry is or
          points to any other kind of file, or if it doesn’t exist
          anymore.

          If 'follow_symlinks' is ‘False’, return ‘True’ only if this
          entry is a directory (without following symlinks); return
          ‘False’ if the entry is any other kind of file or if it
          doesn’t exist anymore.

          The result is cached on the ‘os.DirEntry’ object, with a
          separate cache for 'follow_symlinks' ‘True’ and ‘False’.  Call
          *note os.stat(): 4a3. along with *note stat.S_ISDIR(): 29b1.
          to fetch up-to-date information.

          On the first, uncached call, no system call is required in
          most cases.  Specifically, for non-symlinks, neither Windows
          or Unix require a system call, except on certain Unix file
          systems, such as network file systems, that return
          ‘dirent.d_type == DT_UNKNOWN’.  If the entry is a symlink, a
          system call will be required to follow the symlink unless
          'follow_symlinks' is ‘False’.

          This method can raise *note OSError: 41a, such as *note
          PermissionError: d6b, but *note FileNotFoundError: 42e. is
          caught and not raised.

      -- Method: is_file (*, follow_symlinks=True)

          Return ‘True’ if this entry is a file or a symbolic link
          pointing to a file; return ‘False’ if the entry is or points
          to a directory or other non-file entry, or if it doesn’t exist
          anymore.

          If 'follow_symlinks' is ‘False’, return ‘True’ only if this
          entry is a file (without following symlinks); return ‘False’
          if the entry is a directory or other non-file entry, or if it
          doesn’t exist anymore.

          The result is cached on the ‘os.DirEntry’ object.  Caching,
          system calls made, and exceptions raised are as per *note
          is_dir(): 2d7f.

      -- Method: is_symlink ()

          Return ‘True’ if this entry is a symbolic link (even if
          broken); return ‘False’ if the entry points to a directory or
          any kind of file, or if it doesn’t exist anymore.

          The result is cached on the ‘os.DirEntry’ object.  Call *note
          os.path.islink(): a19. to fetch up-to-date information.

          On the first, uncached call, no system call is required in
          most cases.  Specifically, neither Windows or Unix require a
          system call, except on certain Unix file systems, such as
          network file systems, that return ‘dirent.d_type ==
          DT_UNKNOWN’.

          This method can raise *note OSError: 41a, such as *note
          PermissionError: d6b, but *note FileNotFoundError: 42e. is
          caught and not raised.

      -- Method: is_junction ()

          Return ‘True’ if this entry is a junction (even if broken);
          return ‘False’ if the entry points to a regular directory, any
          kind of file, a symlink, or if it doesn’t exist anymore.

          The result is cached on the ‘os.DirEntry’ object.  Call *note
          os.path.isjunction(): 4a6. to fetch up-to-date information.

          Added in version 3.12.

      -- Method: stat (*, follow_symlinks=True)

          Return a *note stat_result: 1510. object for this entry.  This
          method follows symbolic links by default; to stat a symbolic
          link add the ‘follow_symlinks=False’ argument.

          On Unix, this method always requires a system call.  On
          Windows, it only requires a system call if 'follow_symlinks'
          is ‘True’ and the entry is a reparse point (for example, a
          symbolic link or directory junction).

          On Windows, the ‘st_ino’, ‘st_dev’ and ‘st_nlink’ attributes
          of the *note stat_result: 1510. are always set to zero.  Call
          *note os.stat(): 4a3. to get these attributes.

          The result is cached on the ‘os.DirEntry’ object, with a
          separate cache for 'follow_symlinks' ‘True’ and ‘False’.  Call
          *note os.stat(): 4a3. to fetch up-to-date information.

     Note that there is a nice correspondence between several attributes
     and methods of ‘os.DirEntry’ and of *note pathlib.Path: 229.  In
     particular, the ‘name’ attribute has the same meaning, as do the
     ‘is_dir()’, ‘is_file()’, ‘is_symlink()’, ‘is_junction()’, and
     ‘stat()’ methods.

     Added in version 3.5.

     Changed in version 3.6: Added support for the *note PathLike: c72.
     interface.  Added support for *note bytes: 1c2. paths on Windows.

     Changed in version 3.12: The ‘st_ctime’ attribute of a stat result
     is deprecated on Windows.  The file creation time is properly
     available as ‘st_birthtime’, and in the future ‘st_ctime’ may be
     changed to return zero or the metadata change time, if available.

 -- Function: os.stat (path, *, dir_fd=None, follow_symlinks=True)

     Get the status of a file or a file descriptor.  Perform the
     equivalent of a ‘stat()’ system call on the given path.  'path' may
     be specified as either a string or bytes – directly or indirectly
     through the *note PathLike: c72. interface – or as an open file
     descriptor.  Return a *note stat_result: 1510. object.

     This function normally follows symlinks; to stat a symlink add the
     argument ‘follow_symlinks=False’, or use *note lstat(): 4a4.

     This function can support *note specifying a file descriptor: b78.
     and *note not following symlinks: 112f.

     On Windows, passing ‘follow_symlinks=False’ will disable following
     all name-surrogate reparse points, which includes symlinks and
     directory junctions.  Other types of reparse points that do not
     resemble links or that the operating system is unable to follow
     will be opened directly.  When following a chain of multiple links,
     this may result in the original link being returned instead of the
     non-link that prevented full traversal.  To obtain stat results for
     the final path in this case, use the *note os.path.realpath(): 225.
     function to resolve the path name as far as possible and call *note
     lstat(): 4a4. on the result.  This does not apply to dangling
     symlinks or junction points, which will raise the usual exceptions.

     Example:

          >>> import os
          >>> statinfo = os.stat('somefile.txt')
          >>> statinfo
          os.stat_result(st_mode=33188, st_ino=7876932, st_dev=234881026,
          st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
          st_mtime=1297230027, st_ctime=1297230027)
          >>> statinfo.st_size
          264

     See also
     ........

     *note fstat(): dba. and *note lstat(): 4a4. functions.

     Changed in version 3.3: Added the 'dir_fd' and 'follow_symlinks'
     parameters, specifying a file descriptor instead of a path.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.8: On Windows, all reparse points that can be
     resolved by the operating system are now followed, and passing
     ‘follow_symlinks=False’ disables following all name surrogate
     reparse points.  If the operating system reaches a reparse point
     that it is not able to follow, 'stat' now returns the information
     for the original path as if ‘follow_symlinks=False’ had been
     specified instead of raising an error.

 -- Class: os.stat_result

     Object whose attributes correspond roughly to the members of the
     ‘stat’ structure.  It is used for the result of *note os.stat():
     4a3, *note os.fstat(): dba. and *note os.lstat(): 4a4.

     Attributes:

      -- Attribute: st_mode

          File mode: file type and file mode bits (permissions).

      -- Attribute: st_ino

          Platform dependent, but if non-zero, uniquely identifies the
          file for a given value of ‘st_dev’.  Typically:

             * the inode number on Unix,

             * the file index(8) on Windows

      -- Attribute: st_dev

          Identifier of the device on which this file resides.

      -- Attribute: st_nlink

          Number of hard links.

      -- Attribute: st_uid

          User identifier of the file owner.

      -- Attribute: st_gid

          Group identifier of the file owner.

      -- Attribute: st_size

          Size of the file in bytes, if it is a regular file or a
          symbolic link.  The size of a symbolic link is the length of
          the pathname it contains, without a terminating null byte.

     Timestamps:

      -- Attribute: st_atime

          Time of most recent access expressed in seconds.

      -- Attribute: st_mtime

          Time of most recent content modification expressed in seconds.

      -- Attribute: st_ctime

          Time of most recent metadata change expressed in seconds.

          Changed in version 3.12: ‘st_ctime’ is deprecated on Windows.
          Use ‘st_birthtime’ for the file creation time.  In the future,
          ‘st_ctime’ will contain the time of the most recent metadata
          change, as for other platforms.

      -- Attribute: st_atime_ns

          Time of most recent access expressed in nanoseconds as an
          integer.

          Added in version 3.3.

      -- Attribute: st_mtime_ns

          Time of most recent content modification expressed in
          nanoseconds as an integer.

          Added in version 3.3.

      -- Attribute: st_ctime_ns

          Time of most recent metadata change expressed in nanoseconds
          as an integer.

          Added in version 3.3.

          Changed in version 3.12: ‘st_ctime_ns’ is deprecated on
          Windows.  Use ‘st_birthtime_ns’ for the file creation time.
          In the future, ‘st_ctime’ will contain the time of the most
          recent metadata change, as for other platforms.

      -- Attribute: st_birthtime

          Time of file creation expressed in seconds.  This attribute is
          not always available, and may raise *note AttributeError: 34e.

          Changed in version 3.12: ‘st_birthtime’ is now available on
          Windows.

      -- Attribute: st_birthtime_ns

          Time of file creation expressed in nanoseconds as an integer.
          This attribute is not always available, and may raise *note
          AttributeError: 34e.

          Added in version 3.12.

          Note: The exact meaning and resolution of the *note st_atime:
          2d88, *note st_mtime: 2c13, *note st_ctime: 2d89. and *note
          st_birthtime: 2d8d. attributes depend on the operating system
          and the file system.  For example, on Windows systems using
          the FAT32 file systems, ‘st_mtime’ has 2-second resolution,
          and ‘st_atime’ has only 1-day resolution.  See your operating
          system documentation for details.

          Similarly, although *note st_atime_ns: 2d8a, *note
          st_mtime_ns: 2d8b, *note st_ctime_ns: 2d8c. and *note
          st_birthtime_ns: 2d8e. are always expressed in nanoseconds,
          many systems do not provide nanosecond precision.  On systems
          that do provide nanosecond precision, the floating-point
          object used to store *note st_atime: 2d88, *note st_mtime:
          2c13, *note st_ctime: 2d89. and *note st_birthtime: 2d8d.
          cannot preserve all of it, and as such will be slightly
          inexact.  If you need the exact timestamps you should always
          use ‘st_atime_ns’, ‘st_mtime_ns’, ‘st_ctime_ns’ and
          ‘st_birthtime_ns’.

     On some Unix systems (such as Linux), the following attributes may
     also be available:

      -- Attribute: st_blocks

          Number of 512-byte blocks allocated for file.  This may be
          smaller than *note st_size: 2d87./512 when the file has holes.

      -- Attribute: st_blksize

          “Preferred” blocksize for efficient file system I/O. Writing
          to a file in smaller chunks may cause an inefficient
          read-modify-rewrite.

      -- Attribute: st_rdev

          Type of device if an inode device.

      -- Attribute: st_flags

          User defined flags for file.

     On other Unix systems (such as FreeBSD), the following attributes
     may be available (but may be only filled out if root tries to use
     them):

      -- Attribute: st_gen

          File generation number.

     On Solaris and derivatives, the following attributes may also be
     available:

      -- Attribute: st_fstype

          String that uniquely identifies the type of the filesystem
          that contains the file.

     On macOS systems, the following attributes may also be available:

      -- Attribute: st_rsize

          Real size of the file.

      -- Attribute: st_creator

          Creator of the file.

      -- Attribute: st_type

          File type.

     On Windows systems, the following attributes are also available:

      -- Attribute: st_file_attributes

          Windows file attributes: ‘dwFileAttributes’ member of the
          ‘BY_HANDLE_FILE_INFORMATION’ structure returned by
          ‘GetFileInformationByHandle()’.  See the ‘FILE_ATTRIBUTE_*
          <stat.FILE_ATTRIBUTE_ARCHIVE>’ constants in the *note stat:
          d1. module.

          Added in version 3.5.

      -- Attribute: st_reparse_tag

          When *note st_file_attributes: e6b. has the *note
          FILE_ATTRIBUTE_REPARSE_POINT: 29fe. set, this field contains
          the tag identifying the type of reparse point.  See the *note
          IO_REPARSE_TAG_*: 2a03. constants in the *note stat: d1.
          module.

     The standard module *note stat: d1. defines functions and constants
     that are useful for extracting information from a ‘stat’ structure.
     (On Windows, some items are filled with dummy values.)

     For backward compatibility, a ‘stat_result’ instance is also
     accessible as a tuple of at least 10 integers giving the most
     important (and portable) members of the ‘stat’ structure, in the
     order *note st_mode: a17, *note st_ino: 2d82, *note st_dev: 2d83,
     *note st_nlink: 2d84, *note st_uid: 2d85, *note st_gid: 2d86, *note
     st_size: 2d87, *note st_atime: 2d88, *note st_mtime: 2c13, *note
     st_ctime: 2d89.  More items may be added at the end by some
     implementations.  For compatibility with older Python versions,
     accessing ‘stat_result’ as a tuple always returns integers.

     Changed in version 3.5: Windows now returns the file index as *note
     st_ino: 2d82. when available.

     Changed in version 3.7: Added the *note st_fstype: b80. member to
     Solaris/derivatives.

     Changed in version 3.8: Added the *note st_reparse_tag: a18. member
     on Windows.

     Changed in version 3.8: On Windows, the *note st_mode: a17. member
     now identifies special files as ‘S_IFCHR’, ‘S_IFIFO’ or ‘S_IFBLK’
     as appropriate.

     Changed in version 3.12: On Windows, *note st_ctime: 2d89. is
     deprecated.  Eventually, it will contain the last metadata change
     time, for consistency with other platforms, but for now still
     contains creation time.  Use *note st_birthtime: 2d8d. for the
     creation time.

     On Windows, *note st_ino: 2d82. may now be up to 128 bits,
     depending on the file system.  Previously it would not be above 64
     bits, and larger file identifiers would be arbitrarily packed.

     On Windows, *note st_rdev: 1615. no longer returns a value.
     Previously it would contain the same as *note st_dev: 2d83, which
     was incorrect.

     Added the *note st_birthtime: 2d8d. member on Windows.

 -- Function: os.statvfs (path)

     Perform a ‘statvfs()’ system call on the given path.  The return
     value is an object whose attributes describe the filesystem on the
     given path, and correspond to the members of the ‘statvfs’
     structure, namely: ‘f_bsize’, ‘f_frsize’, ‘f_blocks’, ‘f_bfree’,
     ‘f_bavail’, ‘f_files’, ‘f_ffree’, ‘f_favail’, ‘f_flag’,
     ‘f_namemax’, ‘f_fsid’.

     Two module-level constants are defined for the ‘f_flag’ attribute’s
     bit-flags: if ‘ST_RDONLY’ is set, the filesystem is mounted
     read-only, and if ‘ST_NOSUID’ is set, the semantics of
     setuid/setgid bits are disabled or not supported.

     Additional module-level constants are defined for GNU/glibc based
     systems.  These are ‘ST_NODEV’ (disallow access to device special
     files), ‘ST_NOEXEC’ (disallow program execution), ‘ST_SYNCHRONOUS’
     (writes are synced at once), ‘ST_MANDLOCK’ (allow mandatory locks
     on an FS), ‘ST_WRITE’ (write on file/directory/symlink),
     ‘ST_APPEND’ (append-only file), ‘ST_IMMUTABLE’ (immutable file),
     ‘ST_NOATIME’ (do not update access times), ‘ST_NODIRATIME’ (do not
     update directory access times), ‘ST_RELATIME’ (update atime
     relative to mtime/ctime).

     This function can support *note specifying a file descriptor: b78.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.2: The ‘ST_RDONLY’ and ‘ST_NOSUID’ constants
     were added.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor.

     Changed in version 3.4: The ‘ST_NODEV’, ‘ST_NOEXEC’,
     ‘ST_SYNCHRONOUS’, ‘ST_MANDLOCK’, ‘ST_WRITE’, ‘ST_APPEND’,
     ‘ST_IMMUTABLE’, ‘ST_NOATIME’, ‘ST_NODIRATIME’, and ‘ST_RELATIME’
     constants were added.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.7: Added the ‘f_fsid’ attribute.

 -- Data: os.supports_dir_fd

     A *note set: 5dc. object indicating which functions in the ‘os’
     module accept an open file descriptor for their 'dir_fd' parameter.
     Different platforms provide different features, and the underlying
     functionality Python uses to implement the 'dir_fd' parameter is
     not available on all platforms Python supports.  For consistency’s
     sake, functions that may support 'dir_fd' always allow specifying
     the parameter, but will throw an exception if the functionality is
     used when it’s not locally available.  (Specifying ‘None’ for
     'dir_fd' is always supported on all platforms.)

     To check whether a particular function accepts an open file
     descriptor for its 'dir_fd' parameter, use the ‘in’ operator on
     ‘supports_dir_fd’.  As an example, this expression evaluates to
     ‘True’ if *note os.stat(): 4a3. accepts open file descriptors for
     'dir_fd' on the local platform:

          os.stat in os.supports_dir_fd

     Currently 'dir_fd' parameters only work on Unix platforms; none of
     them work on Windows.

     Added in version 3.3.

 -- Data: os.supports_effective_ids

     A *note set: 5dc. object indicating whether *note os.access():
     1130. permits specifying ‘True’ for its 'effective_ids' parameter
     on the local platform.  (Specifying ‘False’ for 'effective_ids' is
     always supported on all platforms.)  If the local platform supports
     it, the collection will contain ‘os.access()’; otherwise it will be
     empty.

     This expression evaluates to ‘True’ if *note os.access(): 1130.
     supports ‘effective_ids=True’ on the local platform:

          os.access in os.supports_effective_ids

     Currently 'effective_ids' is only supported on Unix platforms; it
     does not work on Windows.

     Added in version 3.3.

 -- Data: os.supports_fd

     A *note set: 5dc. object indicating which functions in the ‘os’
     module permit specifying their 'path' parameter as an open file
     descriptor on the local platform.  Different platforms provide
     different features, and the underlying functionality Python uses to
     accept open file descriptors as 'path' arguments is not available
     on all platforms Python supports.

     To determine whether a particular function permits specifying an
     open file descriptor for its 'path' parameter, use the ‘in’
     operator on ‘supports_fd’.  As an example, this expression
     evaluates to ‘True’ if *note os.chdir(): 610. accepts open file
     descriptors for 'path' on your local platform:

          os.chdir in os.supports_fd

     Added in version 3.3.

 -- Data: os.supports_follow_symlinks

     A *note set: 5dc. object indicating which functions in the ‘os’
     module accept ‘False’ for their 'follow_symlinks' parameter on the
     local platform.  Different platforms provide different features,
     and the underlying functionality Python uses to implement
     'follow_symlinks' is not available on all platforms Python
     supports.  For consistency’s sake, functions that may support
     'follow_symlinks' always allow specifying the parameter, but will
     throw an exception if the functionality is used when it’s not
     locally available.  (Specifying ‘True’ for 'follow_symlinks' is
     always supported on all platforms.)

     To check whether a particular function accepts ‘False’ for its
     'follow_symlinks' parameter, use the ‘in’ operator on
     ‘supports_follow_symlinks’.  As an example, this expression
     evaluates to ‘True’ if you may specify ‘follow_symlinks=False’ when
     calling *note os.stat(): 4a3. on the local platform:

          os.stat in os.supports_follow_symlinks

     Added in version 3.3.

 -- Function: os.symlink (src, dst, target_is_directory=False, *,
          dir_fd=None)

     Create a symbolic link pointing to 'src' named 'dst'.

     The 'src' parameter refers to the target of the link (the file or
     directory being linked to), and 'dst' is the name of the link being
     created.

     On Windows, a symlink represents either a file or a directory, and
     does not morph to the target dynamically.  If the target is
     present, the type of the symlink will be created to match.
     Otherwise, the symlink will be created as a directory if
     'target_is_directory' is ‘True’ or a file symlink (the default)
     otherwise.  On non-Windows platforms, 'target_is_directory' is
     ignored.

     This function can support *note paths relative to directory
     descriptors: 112e.

          Note: On newer versions of Windows 10, unprivileged accounts
          can create symlinks if Developer Mode is enabled.  When
          Developer Mode is not available/enabled, the
          'SeCreateSymbolicLinkPrivilege' privilege is required, or the
          process must be run as an administrator.

          *note OSError: 41a. is raised when the function is called by
          an unprivileged user.

     Raises an *note auditing event: 1a15. ‘os.symlink’ with arguments
     ‘src’, ‘dst’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix, Windows.

     The function is limited on WASI, see *note WebAssembly platforms:
     1910. for more information.

     Changed in version 3.2: Added support for Windows 6.0 (Vista)
     symbolic links.

     Changed in version 3.3: Added the 'dir_fd' parameter, and now allow
     'target_is_directory' on non-Windows platforms.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'src' and 'dst'.

     Changed in version 3.8: Added support for unelevated symlinks on
     Windows with Developer Mode.

 -- Function: os.sync ()

     Force write of everything to disk.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: os.truncate (path, length)

     Truncate the file corresponding to 'path', so that it is at most
     'length' bytes in size.

     This function can support *note specifying a file descriptor: b78.

     Raises an *note auditing event: 1a15. ‘os.truncate’ with arguments
     ‘path’, ‘length’.

     *note Availability: 1ef7.: Unix, Windows.

     Added in version 3.3.

     Changed in version 3.5: Added support for Windows

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.unlink (path, *, dir_fd=None)

     Remove (delete) the file 'path'.  This function is semantically
     identical to *note remove(): 1134.; the ‘unlink’ name is its
     traditional Unix name.  Please see the documentation for ‘remove()’
     for further information.

     Raises an *note auditing event: 1a15. ‘os.remove’ with arguments
     ‘path’, ‘dir_fd’.

     Changed in version 3.3: Added the 'dir_fd' parameter.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.utime (path, times=None, *[, ns], dir_fd=None,
          follow_symlinks=True)

     Set the access and modified times of the file specified by 'path'.

     ‘utime()’ takes two optional parameters, 'times' and 'ns'.  These
     specify the times set on 'path' and are used as follows:

        - If 'ns' is specified, it must be a 2-tuple of the form
          ‘(atime_ns, mtime_ns)’ where each member is an int expressing
          nanoseconds.

        - If 'times' is not ‘None’, it must be a 2-tuple of the form
          ‘(atime, mtime)’ where each member is an int or float
          expressing seconds.

        - If 'times' is ‘None’ and 'ns' is unspecified, this is
          equivalent to specifying ‘ns=(atime_ns, mtime_ns)’ where both
          times are the current time.

     It is an error to specify tuples for both 'times' and 'ns'.

     Note that the exact times you set here may not be returned by a
     subsequent *note stat(): 4a3. call, depending on the resolution
     with which your operating system records access and modification
     times; see ‘stat()’.  The best way to preserve exact times is to
     use the 'st_atime_ns' and 'st_mtime_ns' fields from the ‘os.stat()’
     result object with the 'ns' parameter to ‘utime()’.

     This function can support *note specifying a file descriptor: b78,
     *note paths relative to directory descriptors: 112e. and *note not
     following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.utime’ with arguments
     ‘path’, ‘times’, ‘ns’, ‘dir_fd’.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor, and the 'dir_fd', 'follow_symlinks', and 'ns'
     parameters.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.walk (top, topdown=True, onerror=None,
          followlinks=False)

     Generate the file names in a directory tree by walking the tree
     either top-down or bottom-up.  For each directory in the tree
     rooted at directory 'top' (including 'top' itself), it yields a
     3-tuple ‘(dirpath, dirnames, filenames)’.

     'dirpath' is a string, the path to the directory.  'dirnames' is a
     list of the names of the subdirectories in 'dirpath' (including
     symlinks to directories, and excluding ‘'.'’ and ‘'..'’).
     'filenames' is a list of the names of the non-directory files in
     'dirpath'.  Note that the names in the lists contain no path
     components.  To get a full path (which begins with 'top') to a file
     or directory in 'dirpath', do ‘os.path.join(dirpath, name)’.
     Whether or not the lists are sorted depends on the file system.  If
     a file is removed from or added to the 'dirpath' directory during
     generating the lists, whether a name for that file be included is
     unspecified.

     If optional argument 'topdown' is ‘True’ or not specified, the
     triple for a directory is generated before the triples for any of
     its subdirectories (directories are generated top-down).  If
     'topdown' is ‘False’, the triple for a directory is generated after
     the triples for all of its subdirectories (directories are
     generated bottom-up).  No matter the value of 'topdown', the list
     of subdirectories is retrieved before the tuples for the directory
     and its subdirectories are generated.

     When 'topdown' is ‘True’, the caller can modify the 'dirnames' list
     in-place (perhaps using *note del: 18c2. or slice assignment), and
     ‘walk()’ will only recurse into the subdirectories whose names
     remain in 'dirnames'; this can be used to prune the search, impose
     a specific order of visiting, or even to inform ‘walk()’ about
     directories the caller creates or renames before it resumes
     ‘walk()’ again.  Modifying 'dirnames' when 'topdown' is ‘False’ has
     no effect on the behavior of the walk, because in bottom-up mode
     the directories in 'dirnames' are generated before 'dirpath' itself
     is generated.

     By default, errors from the *note scandir(): a6d. call are ignored.
     If optional argument 'onerror' is specified, it should be a
     function; it will be called with one argument, an *note OSError:
     41a. instance.  It can report the error to continue with the walk,
     or raise the exception to abort the walk.  Note that the filename
     is available as the ‘filename’ attribute of the exception object.

     By default, ‘walk()’ will not walk down into symbolic links that
     resolve to directories.  Set 'followlinks' to ‘True’ to visit
     directories pointed to by symlinks, on systems that support them.

          Note: Be aware that setting 'followlinks' to ‘True’ can lead
          to infinite recursion if a link points to a parent directory
          of itself.  ‘walk()’ does not keep track of the directories it
          visited already.

          Note: If you pass a relative pathname, don’t change the
          current working directory between resumptions of ‘walk()’.
          ‘walk()’ never changes the current directory, and assumes that
          its caller doesn’t either.

     This example displays the number of bytes taken by non-directory
     files in each directory under the starting directory, except that
     it doesn’t look under any ‘__pycache__’ subdirectory:

          import os
          from os.path import join, getsize
          for root, dirs, files in os.walk('python/Lib/xml'):
              print(root, "consumes", end=" ")
              print(sum(getsize(join(root, name)) for name in files), end=" ")
              print("bytes in", len(files), "non-directory files")
              if '__pycache__' in dirs:
                  dirs.remove('__pycache__')  # don't visit __pycache__ directories

     In the next example (simple implementation of *note
     shutil.rmtree(): 301.), walking the tree bottom-up is essential,
     *note rmdir(): 1137. doesn’t allow deleting a directory before the
     directory is empty:

          # Delete everything reachable from the directory named in "top",
          # assuming there are no symbolic links.
          # CAUTION:  This is dangerous!  For example, if top == '/', it
          # could delete all your disk files.
          import os
          for root, dirs, files in os.walk(top, topdown=False):
              for name in files:
                  os.remove(os.path.join(root, name))
              for name in dirs:
                  os.rmdir(os.path.join(root, name))
          os.rmdir(top)

     Raises an *note auditing event: 1a15. ‘os.walk’ with arguments
     ‘top’, ‘topdown’, ‘onerror’, ‘followlinks’.

     Changed in version 3.5: This function now calls *note os.scandir():
     a6d. instead of *note os.listdir(): 113e, making it faster by
     reducing the number of calls to *note os.stat(): 4a3.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.fwalk (top='.', topdown=True, onerror=None, *,
          follow_symlinks=False, dir_fd=None)

     This behaves exactly like *note walk(): 4ac, except that it yields
     a 4-tuple ‘(dirpath, dirnames, filenames, dirfd)’, and it supports
     ‘dir_fd’.

     'dirpath', 'dirnames' and 'filenames' are identical to *note
     walk(): 4ac. output, and 'dirfd' is a file descriptor referring to
     the directory 'dirpath'.

     This function always supports *note paths relative to directory
     descriptors: 112e. and *note not following symlinks: 112f.  Note
     however that, unlike other functions, the ‘fwalk()’ default value
     for 'follow_symlinks' is ‘False’.

          Note: Since ‘fwalk()’ yields file descriptors, those are only
          valid until the next iteration step, so you should duplicate
          them (e.g.  with *note dup(): 1b6d.) if you want to keep them
          longer.

     This example displays the number of bytes taken by non-directory
     files in each directory under the starting directory, except that
     it doesn’t look under any ‘__pycache__’ subdirectory:

          import os
          for root, dirs, files, rootfd in os.fwalk('python/Lib/xml'):
              print(root, "consumes", end=" ")
              print(sum([os.stat(name, dir_fd=rootfd).st_size for name in files]),
                    end=" ")
              print("bytes in", len(files), "non-directory files")
              if '__pycache__' in dirs:
                  dirs.remove('__pycache__')  # don't visit __pycache__ directories

     In the next example, walking the tree bottom-up is essential: *note
     rmdir(): 1137. doesn’t allow deleting a directory before the
     directory is empty:

          # Delete everything reachable from the directory named in "top",
          # assuming there are no symbolic links.
          # CAUTION:  This is dangerous!  For example, if top == '/', it
          # could delete all your disk files.
          import os
          for root, dirs, files, rootfd in os.fwalk(top, topdown=False):
              for name in files:
                  os.unlink(name, dir_fd=rootfd)
              for name in dirs:
                  os.rmdir(name, dir_fd=rootfd)

     Raises an *note auditing event: 1a15. ‘os.fwalk’ with arguments
     ‘top’, ‘topdown’, ‘onerror’, ‘follow_symlinks’, ‘dir_fd’.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.7: Added support for *note bytes: 1c2. paths.

 -- Function: os.memfd_create (name[, flags=os.MFD_CLOEXEC])

     Create an anonymous file and return a file descriptor that refers
     to it.  'flags' must be one of the ‘os.MFD_*’ constants available
     on the system (or a bitwise ORed combination of them).  By default,
     the new file descriptor is *note non-inheritable: f30.

     The name supplied in 'name' is used as a filename and will be
     displayed as the target of the corresponding symbolic link in the
     directory ‘/proc/self/fd/’.  The displayed name is always prefixed
     with ‘memfd:’ and serves only for debugging purposes.  Names do not
     affect the behavior of the file descriptor, and as such multiple
     files can have the same name without any side effects.

     *note Availability: 1ef7.: Linux >= 3.17 with glibc >= 2.27.

     Added in version 3.8.

 -- Data: os.MFD_CLOEXEC
 -- Data: os.MFD_ALLOW_SEALING
 -- Data: os.MFD_HUGETLB
 -- Data: os.MFD_HUGE_SHIFT
 -- Data: os.MFD_HUGE_MASK
 -- Data: os.MFD_HUGE_64KB
 -- Data: os.MFD_HUGE_512KB
 -- Data: os.MFD_HUGE_1MB
 -- Data: os.MFD_HUGE_2MB
 -- Data: os.MFD_HUGE_8MB
 -- Data: os.MFD_HUGE_16MB
 -- Data: os.MFD_HUGE_32MB
 -- Data: os.MFD_HUGE_256MB
 -- Data: os.MFD_HUGE_512MB
 -- Data: os.MFD_HUGE_1GB
 -- Data: os.MFD_HUGE_2GB
 -- Data: os.MFD_HUGE_16GB

     These flags can be passed to *note memfd_create(): a16.

     *note Availability: 1ef7.: Linux >= 3.17 with glibc >= 2.27

     The ‘MFD_HUGE*’ flags are only available since Linux 4.14.

     Added in version 3.8.

 -- Function: os.eventfd (initval[, flags=os.EFD_CLOEXEC])

     Create and return an event file descriptor.  The file descriptors
     supports raw *note read(): dc3. and *note write(): dc9. with a
     buffer size of 8, *note select(): dce, *note poll(): 2da7. and
     similar.  See man page ‘eventfd(2)(9)’ for more information.  By
     default, the new file descriptor is *note non-inheritable: f30.

     'initval' is the initial value of the event counter.  The initial
     value must be a 32 bit unsigned integer.  Please note that the
     initial value is limited to a 32 bit unsigned int although the
     event counter is an unsigned 64 bit integer with a maximum value of
     2^64-2.

     'flags' can be constructed from *note EFD_CLOEXEC: 18fe, *note
     EFD_NONBLOCK: 18ff, and *note EFD_SEMAPHORE: 1900.

     If *note EFD_SEMAPHORE: 1900. is specified and the event counter is
     non-zero, *note eventfd_read(): 2da8. returns 1 and decrements the
     counter by one.

     If *note EFD_SEMAPHORE: 1900. is not specified and the event
     counter is non-zero, *note eventfd_read(): 2da8. returns the
     current event counter value and resets the counter to zero.

     If the event counter is zero and *note EFD_NONBLOCK: 18ff. is not
     specified, *note eventfd_read(): 2da8. blocks.

     *note eventfd_write(): 2da9. increments the event counter.  Write
     blocks if the write operation would increment the counter to a
     value larger than 2^64-2.

     Example:

          import os

          # semaphore with start value '1'
          fd = os.eventfd(1, os.EFD_SEMAPHORE | os.EFD_CLOEXEC)
          try:
              # acquire semaphore
              v = os.eventfd_read(fd)
              try:
                  do_work()
              finally:
                  # release semaphore
                  os.eventfd_write(fd, v)
          finally:
              os.close(fd)

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.10.

 -- Function: os.eventfd_read (fd)

     Read value from an *note eventfd(): 81e. file descriptor and return
     a 64 bit unsigned int.  The function does not verify that 'fd' is
     an ‘eventfd()’.

     *note Availability: 1ef7.: Linux >= 2.6.27

     Added in version 3.10.

 -- Function: os.eventfd_write (fd, value)

     Add value to an *note eventfd(): 81e. file descriptor.  'value'
     must be a 64 bit unsigned int.  The function does not verify that
     'fd' is an ‘eventfd()’.

     *note Availability: 1ef7.: Linux >= 2.6.27

     Added in version 3.10.

 -- Data: os.EFD_CLOEXEC

     Set close-on-exec flag for new *note eventfd(): 81e. file
     descriptor.

     *note Availability: 1ef7.: Linux >= 2.6.27

     Added in version 3.10.

 -- Data: os.EFD_NONBLOCK

     Set *note O_NONBLOCK: e6e. status flag for new *note eventfd():
     81e. file descriptor.

     *note Availability: 1ef7.: Linux >= 2.6.27

     Added in version 3.10.

 -- Data: os.EFD_SEMAPHORE

     Provide semaphore-like semantics for reads from an *note eventfd():
     81e. file descriptor.  On read the internal counter is decremented
     by one.

     *note Availability: 1ef7.: Linux >= 2.6.30

     Added in version 3.10.

* Menu:

* Timer File Descriptors::
* Linux extended attributes::

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/access(2)

   (2) https://peps.python.org/pep-0529/

   (3) https://bugs.python.org/issue?@action=redirect&bpo=21082

   (4) 
https://pubs.opengroup.org/onlinepubs/009695399/functions/opendir.html

   (5) 
https://pubs.opengroup.org/onlinepubs/009695399/functions/readdir_r.html

   (6) 
https://msdn.microsoft.com/en-us/library/windows/desktop/aa364418(v=vs.85).aspx

   (7) 
https://msdn.microsoft.com/en-us/library/windows/desktop/aa364428(v=vs.85).aspx

   (8) https://msdn.microsoft.com/en-us/library/aa363788

   (9) https://manpages.debian.org/eventfd(2)


File: python.info,  Node: Timer File Descriptors,  Next: Linux extended attributes,  Up: Files and Directories

5.16.1.9 Timer File Descriptors
...............................

Added in version 3.13.

These functions provide support for Linux’s 'timer file descriptor' API.
Naturally, they are all only available on Linux.

 -- Function: os.timerfd_create (clockid, /, *, flags=0)

     Create and return a timer file descriptor ('timerfd').

     The file descriptor returned by ‘timerfd_create()’ supports:

        - *note read(): dc3.

        - *note select(): dce.

        - *note poll(): 2da7.

     The file descriptor’s *note read(): dc3. method can be called with
     a buffer size of 8.  If the timer has already expired one or more
     times, ‘read()’ returns the number of expirations with the host’s
     endianness, which may be converted to an *note int: 257. by
     ‘int.from_bytes(x, byteorder=sys.byteorder)’.

     *note select(): dce. and *note poll(): 2da7. can be used to wait
     until timer expires and the file descriptor is readable.

     'clockid' must be a valid *note clock ID: 2dab, as defined in the
     *note time: ee. module:

        - *note time.CLOCK_REALTIME: 69d.

        - *note time.CLOCK_MONOTONIC: 69c.

        - *note time.CLOCK_BOOTTIME: bac. (Since Linux 3.15 for
          timerfd_create)

     If 'clockid' is *note time.CLOCK_REALTIME: 69d, a settable
     system-wide real-time clock is used.  If system clock is changed,
     timer setting need to be updated.  To cancel timer when system
     clock is changed, see *note TFD_TIMER_CANCEL_ON_SET: 219.

     If 'clockid' is *note time.CLOCK_MONOTONIC: 69c, a non-settable
     monotonically increasing clock is used.  Even if the system clock
     is changed, the timer setting will not be affected.

     If 'clockid' is *note time.CLOCK_BOOTTIME: bac, same as *note
     time.CLOCK_MONOTONIC: 69c. except it includes any time that the
     system is suspended.

     The file descriptor’s behaviour can be modified by specifying a
     'flags' value.  Any of the following variables may be used,
     combined using bitwise OR (the ‘|’ operator):

        - *note TFD_NONBLOCK: 216.

        - *note TFD_CLOEXEC: 217.

     If *note TFD_NONBLOCK: 216. is not set as a flag, *note read():
     dc3. blocks until the timer expires.  If it is set as a flag,
     ‘read()’ doesn’t block, but If there hasn’t been an expiration
     since the last call to read, ‘read()’ raises *note OSError: 41a.
     with ‘errno’ is set to *note errno.EAGAIN: 2457.

     *note TFD_CLOEXEC: 217. is always set by Python automatically.

     The file descriptor must be closed with *note os.close(): b90. when
     it is no longer needed, or else the file descriptor will be leaked.

     See also
     ........

     The ‘timerfd_create(2)(1)’ man page.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Function: os.timerfd_settime (fd, /, *, flags=flags, initial=0.0,
          interval=0.0)

     Alter a timer file descriptor’s internal timer.  This function
     operates the same interval timer as *note timerfd_settime_ns():
     213.

     'fd' must be a valid timer file descriptor.

     The timer’s behaviour can be modified by specifying a 'flags'
     value.  Any of the following variables may be used, combined using
     bitwise OR (the ‘|’ operator):

        - *note TFD_TIMER_ABSTIME: 218.

        - *note TFD_TIMER_CANCEL_ON_SET: 219.

     The timer is disabled by setting 'initial' to zero (‘0’).  If
     'initial' is equal to or greater than zero, the timer is enabled.
     If 'initial' is less than zero, it raises an *note OSError: 41a.
     exception with ‘errno’ set to *note errno.EINVAL: 1b7f.

     By default the timer will fire when 'initial' seconds have elapsed.
     (If 'initial' is zero, timer will fire immediately.)

     However, if the *note TFD_TIMER_ABSTIME: 218. flag is set, the
     timer will fire when the timer’s clock (set by 'clockid' in *note
     timerfd_create(): 211.) reaches 'initial' seconds.

     The timer’s interval is set by the 'interval' *note float: 2f7.  If
     'interval' is zero, the timer only fires once, on the initial
     expiration.  If 'interval' is greater than zero, the timer fires
     every time 'interval' seconds have elapsed since the previous
     expiration.  If 'interval' is less than zero, it raises *note
     OSError: 41a. with ‘errno’ set to *note errno.EINVAL: 1b7f.

     If the *note TFD_TIMER_CANCEL_ON_SET: 219. flag is set along with
     *note TFD_TIMER_ABSTIME: 218. and the clock for this timer is *note
     time.CLOCK_REALTIME: 69d, the timer is marked as cancelable if the
     real-time clock is changed discontinuously.  Reading the descriptor
     is aborted with the error ECANCELED.

     Linux manages system clock as UTC. A daylight-savings time
     transition is done by changing time offset only and doesn’t cause
     discontinuous system clock change.

     Discontinuous system clock change will be caused by the following
     events:

        - ‘settimeofday’

        - ‘clock_settime’

        - set the system date and time by ‘date’ command

     Return a two-item tuple of (‘next_expiration’, ‘interval’) from the
     previous timer state, before this function executed.

     See also
     ........

     ‘timerfd_create(2)(2)’, ‘timerfd_settime(2)(3)’,
     ‘settimeofday(2)(4)’, ‘clock_settime(2)(5)’, and ‘date(1)(6)’.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Function: os.timerfd_settime_ns (fd, /, *, flags=0, initial=0,
          interval=0)

     Similar to *note timerfd_settime(): 212, but use time as
     nanoseconds.  This function operates the same interval timer as
     ‘timerfd_settime()’.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Function: os.timerfd_gettime (fd, /)

     Return a two-item tuple of floats (‘next_expiration’, ‘interval’).

     ‘next_expiration’ denotes the relative time until the timer next
     fires, regardless of if the *note TFD_TIMER_ABSTIME: 218. flag is
     set.

     ‘interval’ denotes the timer’s interval.  If zero, the timer will
     only fire once, after ‘next_expiration’ seconds have elapsed.

     See also
     ........

     ‘timerfd_gettime(2)(7)’

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Function: os.timerfd_gettime_ns (fd, /)

     Similar to *note timerfd_gettime(): 214, but return time as
     nanoseconds.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Data: os.TFD_NONBLOCK

     A flag for the *note timerfd_create(): 211. function, which sets
     the *note O_NONBLOCK: e6e. status flag for the new timer file
     descriptor.  If *note TFD_NONBLOCK: 216. is not set as a flag,
     *note read(): dc3. blocks.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Data: os.TFD_CLOEXEC

     A flag for the *note timerfd_create(): 211. function, If *note
     TFD_CLOEXEC: 217. is set as a flag, set close-on-exec flag for new
     file descriptor.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Data: os.TFD_TIMER_ABSTIME

     A flag for the *note timerfd_settime(): 212. and *note
     timerfd_settime_ns(): 213. functions.  If this flag is set,
     'initial' is interpreted as an absolute value on the timer’s clock
     (in UTC seconds or nanoseconds since the Unix Epoch).

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

 -- Data: os.TFD_TIMER_CANCEL_ON_SET

     A flag for the *note timerfd_settime(): 212. and *note
     timerfd_settime_ns(): 213. functions along with *note
     TFD_TIMER_ABSTIME: 218.  The timer is cancelled when the time of
     the underlying clock changes discontinuously.

     *note Availability: 1ef7.: Linux >= 2.6.27 with glibc >= 2.8

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/timerfd_create(2)

   (2) https://manpages.debian.org/timerfd_create(2)

   (3) https://manpages.debian.org/timerfd_settime(2)

   (4) https://manpages.debian.org/settimeofday(2)

   (5) https://manpages.debian.org/clock_settime(2)

   (6) https://manpages.debian.org/date(1)

   (7) https://manpages.debian.org/timerfd_gettime(2)


File: python.info,  Node: Linux extended attributes,  Prev: Timer File Descriptors,  Up: Files and Directories

5.16.1.10 Linux extended attributes
...................................

Added in version 3.3.

These functions are all available on Linux only.

 -- Function: os.getxattr (path, attribute, *, follow_symlinks=True)

     Return the value of the extended filesystem attribute 'attribute'
     for 'path'.  'attribute' can be bytes or str (directly or
     indirectly through the *note PathLike: c72. interface).  If it is
     str, it is encoded with the filesystem encoding.

     This function can support *note specifying a file descriptor: b78.
     and *note not following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.getxattr’ with arguments
     ‘path’, ‘attribute’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'path' and 'attribute'.

 -- Function: os.listxattr (path=None, *, follow_symlinks=True)

     Return a list of the extended filesystem attributes on 'path'.  The
     attributes in the list are represented as strings decoded with the
     filesystem encoding.  If 'path' is ‘None’, ‘listxattr()’ will
     examine the current directory.

     This function can support *note specifying a file descriptor: b78.
     and *note not following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.listxattr’ with argument
     ‘path’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os.removexattr (path, attribute, *, follow_symlinks=True)

     Removes the extended filesystem attribute 'attribute' from 'path'.
     'attribute' should be bytes or str (directly or indirectly through
     the *note PathLike: c72. interface).  If it is a string, it is
     encoded with the *note filesystem encoding and error handler: 53e.

     This function can support *note specifying a file descriptor: b78.
     and *note not following symlinks: 112f.

     Raises an *note auditing event: 1a15. ‘os.removexattr’ with
     arguments ‘path’, ‘attribute’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'path' and 'attribute'.

 -- Function: os.setxattr (path, attribute, value, flags=0, *,
          follow_symlinks=True)

     Set the extended filesystem attribute 'attribute' on 'path' to
     'value'.  'attribute' must be a bytes or str with no embedded NULs
     (directly or indirectly through the *note PathLike: c72.
     interface).  If it is a str, it is encoded with the *note
     filesystem encoding and error handler: 53e.  'flags' may be *note
     XATTR_REPLACE: 2dad. or *note XATTR_CREATE: 2dae.  If
     ‘XATTR_REPLACE’ is given and the attribute does not exist,
     ‘ENODATA’ will be raised.  If ‘XATTR_CREATE’ is given and the
     attribute already exists, the attribute will not be created and
     ‘EEXISTS’ will be raised.

     This function can support *note specifying a file descriptor: b78.
     and *note not following symlinks: 112f.

          Note: A bug in Linux kernel versions less than 2.6.39 caused
          the flags argument to be ignored on some filesystems.

     Raises an *note auditing event: 1a15. ‘os.setxattr’ with arguments
     ‘path’, ‘attribute’, ‘value’, ‘flags’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0. for
     'path' and 'attribute'.

 -- Data: os.XATTR_SIZE_MAX

     The maximum size the value of an extended attribute can be.
     Currently, this is 64 KiB on Linux.

 -- Data: os.XATTR_CREATE

     This is a possible value for the flags argument in *note
     setxattr(): 114b.  It indicates the operation must create an
     attribute.

 -- Data: os.XATTR_REPLACE

     This is a possible value for the flags argument in *note
     setxattr(): 114b.  It indicates the operation must replace an
     existing attribute.


File: python.info,  Node: Process Management,  Next: Interface to the scheduler,  Prev: Files and Directories,  Up: os — Miscellaneous operating system interfaces

5.16.1.11 Process Management
............................

These functions may be used to create and manage processes.

The various *note exec*: 2db2. functions take a list of arguments for
the new program loaded into the process.  In each case, the first of
these arguments is passed to the new program as its own name rather than
as an argument a user may have typed on a command line.  For the C
programmer, this is the ‘argv[0]’ passed to a program’s ‘main()’.  For
example, ‘os.execv('/bin/echo', ['foo', 'bar'])’ will only print ‘bar’
on standard output; ‘foo’ will seem to be ignored.

 -- Function: os.abort ()

     Generate a ‘SIGABRT’ signal to the current process.  On Unix, the
     default behavior is to produce a core dump; on Windows, the process
     immediately returns an exit code of ‘3’.  Be aware that calling
     this function will not call the Python signal handler registered
     for ‘SIGABRT’ with *note signal.signal(): 1178.

 -- Function: os.add_dll_directory (path)

     Add a path to the DLL search path.

     This search path is used when resolving dependencies for imported
     extension modules (the module itself is resolved through *note
     sys.path: 3b7.), and also by *note ctypes: 2a.

     Remove the directory by calling 'close()' on the returned object or
     using it in a *note with: 5d5. statement.

     See the Microsoft documentation(1) for more information about how
     DLLs are loaded.

     Raises an *note auditing event: 1a15. ‘os.add_dll_directory’ with
     argument ‘path’.

     *note Availability: 1ef7.: Windows.

     Added in version 3.8: Previous versions of CPython would resolve
     DLLs using the default behavior for the current process.  This led
     to inconsistencies, such as only sometimes searching ‘PATH’ or the
     current working directory, and OS functions such as
     ‘AddDllDirectory’ having no effect.

     In 3.8, the two primary ways DLLs are loaded now explicitly
     override the process-wide behavior to ensure consistency.  See the
     *note porting notes: ab3. for information on updating libraries.

 -- Function: os.execl (path, arg0, arg1, ...)
 -- Function: os.execle (path, arg0, arg1, ..., env)
 -- Function: os.execlp (file, arg0, arg1, ...)
 -- Function: os.execlpe (file, arg0, arg1, ..., env)
 -- Function: os.execv (path, args)
 -- Function: os.execve (path, args, env)
 -- Function: os.execvp (file, args)
 -- Function: os.execvpe (file, args, env)

     These functions all execute a new program, replacing the current
     process; they do not return.  On Unix, the new executable is loaded
     into the current process, and will have the same process id as the
     caller.  Errors will be reported as *note OSError: 41a. exceptions.

     The current process is replaced immediately.  Open file objects and
     descriptors are not flushed, so if there may be data buffered on
     these open files, you should flush them using *note flush(): 2db9.
     or *note os.fsync(): dbc. before calling an ‘exec*’ function.

     The “l” and “v” variants of the ‘exec*’ functions differ in how
     command-line arguments are passed.  The “l” variants are perhaps
     the easiest to work with if the number of parameters is fixed when
     the code is written; the individual parameters simply become
     additional parameters to the ‘execl*()’ functions.  The “v”
     variants are good when the number of parameters is variable, with
     the arguments being passed in a list or tuple as the 'args'
     parameter.  In either case, the arguments to the child process
     should start with the name of the command being run, but this is
     not enforced.

     The variants which include a “p” near the end (‘execlp()’,
     ‘execlpe()’, ‘execvp()’, and ‘execvpe()’) will use the ‘PATH’
     environment variable to locate the program 'file'.  When the
     environment is being replaced (using one of the ‘exec*e’ variants,
     discussed in the next paragraph), the new environment is used as
     the source of the ‘PATH’ variable.  The other variants, ‘execl()’,
     ‘execle()’, ‘execv()’, and ‘execve()’, will not use the ‘PATH’
     variable to locate the executable; 'path' must contain an
     appropriate absolute or relative path.  Relative paths must include
     at least one slash, even on Windows, as plain names will not be
     resolved.

     For ‘execle()’, ‘execlpe()’, ‘execve()’, and ‘execvpe()’ (note that
     these all end in “e”), the 'env' parameter must be a mapping which
     is used to define the environment variables for the new process
     (these are used instead of the current process’ environment); the
     functions ‘execl()’, ‘execlp()’, ‘execv()’, and ‘execvp()’ all
     cause the new process to inherit the environment of the current
     process.

     For ‘execve()’ on some platforms, 'path' may also be specified as
     an open file descriptor.  This functionality may not be supported
     on your platform; you can check whether or not it is available
     using *note os.supports_fd: 1141.  If it is unavailable, using it
     will raise a *note NotImplementedError: 228.

     Raises an *note auditing event: 1a15. ‘os.exec’ with arguments
     ‘path’, ‘args’, ‘env’.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not Android,
     not iOS.

     Changed in version 3.3: Added support for specifying 'path' as an
     open file descriptor for ‘execve()’.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: os._exit (n)

     Exit the process with status 'n', without calling cleanup handlers,
     flushing stdio buffers, etc.

          Note: The standard way to exit is *note sys.exit(n): 1394.
          ‘_exit()’ should normally only be used in the child process
          after a *note fork(): 197.

The following exit codes are defined and can be used with *note _exit():
2451, although they are not required.  These are typically used for
system programs written in Python, such as a mail server’s external
command delivery program.

     Note: Some of these may not be available on all Unix platforms,
     since there is some variation.  These constants are defined where
     they are defined by the underlying platform.

 -- Data: os.EX_OK

     Exit code that means no error occurred.  May be taken from the
     defined value of ‘EXIT_SUCCESS’ on some platforms.  Generally has a
     value of zero.

     *note Availability: 1ef7.: Unix, Windows.

 -- Data: os.EX_USAGE

     Exit code that means the command was used incorrectly, such as when
     the wrong number of arguments are given.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_DATAERR

     Exit code that means the input data was incorrect.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_NOINPUT

     Exit code that means an input file did not exist or was not
     readable.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_NOUSER

     Exit code that means a specified user did not exist.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_NOHOST

     Exit code that means a specified host did not exist.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_UNAVAILABLE

     Exit code that means that a required service is unavailable.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_SOFTWARE

     Exit code that means an internal software error was detected.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_OSERR

     Exit code that means an operating system error was detected, such
     as the inability to fork or create a pipe.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_OSFILE

     Exit code that means some system file did not exist, could not be
     opened, or had some other kind of error.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_CANTCREAT

     Exit code that means a user specified output file could not be
     created.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_IOERR

     Exit code that means that an error occurred while doing I/O on some
     file.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_TEMPFAIL

     Exit code that means a temporary failure occurred.  This indicates
     something that may not really be an error, such as a network
     connection that couldn’t be made during a retryable operation.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_PROTOCOL

     Exit code that means that a protocol exchange was illegal, invalid,
     or not understood.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_NOPERM

     Exit code that means that there were insufficient permissions to
     perform the operation (but not intended for file system problems).

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_CONFIG

     Exit code that means that some kind of configuration error
     occurred.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Data: os.EX_NOTFOUND

     Exit code that means something like “an entry was not found”.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.fork ()

     Fork a child process.  Return ‘0’ in the child and the child’s
     process id in the parent.  If an error occurs *note OSError: 41a.
     is raised.

     Note that some platforms including FreeBSD <= 6.3 and Cygwin have
     known issues when using ‘fork()’ from a thread.

     Raises an *note auditing event: 1a15. ‘os.fork’ with no arguments.

          Warning: If you use TLS sockets in an application calling
          ‘fork()’, see the warning in the *note ssl: d0. documentation.

          Warning: On macOS the use of this function is unsafe when
          mixed with using higher-level system APIs, and that includes
          using *note urllib.request: 10b.

     Changed in version 3.8: Calling ‘fork()’ in a subinterpreter is no
     longer supported (*note RuntimeError: 195. is raised).

     Changed in version 3.12: If Python is able to detect that your
     process has multiple threads, *note os.fork(): 197. now raises a
     *note DeprecationWarning: 1a5.

     We chose to surface this as a warning, when detectable, to better
     inform developers of a design problem that the POSIX platform
     specifically notes as not supported.  Even in code that 'appears'
     to work, it has never been safe to mix threading with *note
     os.fork(): 197. on POSIX platforms.  The CPython runtime itself has
     always made API calls that are not safe for use in the child
     process when threads existed in the parent (such as ‘malloc’ and
     ‘free’).

     Users of macOS or users of libc or malloc implementations other
     than those typically found in glibc to date are among those already
     more likely to experience deadlocks running such code.

     See this discussion on fork being incompatible with threads(2) for
     technical details of why we’re surfacing this longstanding platform
     compatibility problem to developers.

     *note Availability: 1ef7.: POSIX, not WASI, not Android, not iOS.

 -- Function: os.forkpty ()

     Fork a child process, using a new pseudo-terminal as the child’s
     controlling terminal.  Return a pair of ‘(pid, fd)’, where 'pid' is
     ‘0’ in the child, the new child’s process id in the parent, and
     'fd' is the file descriptor of the master end of the
     pseudo-terminal.  For a more portable approach, use the *note pty:
     b1. module.  If an error occurs *note OSError: 41a. is raised.

     Raises an *note auditing event: 1a15. ‘os.forkpty’ with no
     arguments.

          Warning: On macOS the use of this function is unsafe when
          mixed with using higher-level system APIs, and that includes
          using *note urllib.request: 10b.

     Changed in version 3.8: Calling ‘forkpty()’ in a subinterpreter is
     no longer supported (*note RuntimeError: 195. is raised).

     Changed in version 3.12: If Python is able to detect that your
     process has multiple threads, this now raises a *note
     DeprecationWarning: 1a5.  See the longer explanation on *note
     os.fork(): 197.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.kill (pid, sig, /)

     Send signal 'sig' to the process 'pid'.  Constants for the specific
     signals available on the host platform are defined in the *note
     signal: c6. module.

     Windows: The *note signal.CTRL_C_EVENT: 13b5. and *note
     signal.CTRL_BREAK_EVENT: 13b6. signals are special signals which
     can only be sent to console processes which share a common console
     window, e.g., some subprocesses.  Any other value for 'sig' will
     cause the process to be unconditionally killed by the
     TerminateProcess API, and the exit code will be set to 'sig'.

     See also *note signal.pthread_kill(): 1175.

     Raises an *note auditing event: 1a15. ‘os.kill’ with arguments
     ‘pid’, ‘sig’.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not iOS.

     Changed in version 3.2: Added Windows support.

 -- Function: os.killpg (pgid, sig, /)

     Send the signal 'sig' to the process group 'pgid'.

     Raises an *note auditing event: 1a15. ‘os.killpg’ with arguments
     ‘pgid’, ‘sig’.

     *note Availability: 1ef7.: Unix, not WASI, not iOS.

 -- Function: os.nice (increment, /)

     Add 'increment' to the process’s “niceness”.  Return the new
     niceness.

     *note Availability: 1ef7.: Unix, not WASI.

 -- Function: os.pidfd_open (pid, flags=0)

     Return a file descriptor referring to the process 'pid' with
     'flags' set.  This descriptor can be used to perform process
     management without races and signals.

     See the ‘pidfd_open(2)(3)’ man page for more details.

     *note Availability: 1ef7.: Linux >= 5.3, Android >= *note
     build-time: ba8. API level 31

     Added in version 3.9.

      -- Data: os.PIDFD_NONBLOCK

          This flag indicates that the file descriptor will be
          non-blocking.  If the process referred to by the file
          descriptor has not yet terminated, then an attempt to wait on
          the file descriptor using ‘waitid(2)(4)’ will immediately
          return the error *note EAGAIN: 2457. rather than blocking.

     *note Availability: 1ef7.: Linux >= 5.10

     Added in version 3.12.

 -- Function: os.plock (op, /)

     Lock program segments into memory.  The value of 'op' (defined in
     ‘<sys/lock.h>’) determines which segments are locked.

     *note Availability: 1ef7.: Unix, not WASI, not iOS.

 -- Function: os.popen (cmd, mode='r', buffering=-1)

     Open a pipe to or from command 'cmd'.  The return value is an open
     file object connected to the pipe, which can be read or written
     depending on whether 'mode' is ‘'r'’ (default) or ‘'w'’.  The
     'buffering' argument have the same meaning as the corresponding
     argument to the built-in *note open(): 51f. function.  The returned
     file object reads or writes text strings rather than bytes.

     The ‘close’ method returns *note None: 678. if the subprocess
     exited successfully, or the subprocess’s return code if there was
     an error.  On POSIX systems, if the return code is positive it
     represents the return value of the process left-shifted by one
     byte.  If the return code is negative, the process was terminated
     by the signal given by the negated value of the return code.  (For
     example, the return value might be ‘- signal.SIGKILL’ if the
     subprocess was killed.)  On Windows systems, the return value
     contains the signed integer return code from the child process.

     On Unix, *note waitstatus_to_exitcode(): 926. can be used to
     convert the ‘close’ method result (exit status) into an exit code
     if it is not ‘None’.  On Windows, the ‘close’ method result is
     directly the exit code (or ‘None’).

     This is implemented using *note subprocess.Popen: 199.; see that
     class’s documentation for more powerful ways to manage and
     communicate with subprocesses.

     *note Availability: 1ef7.: not WASI, not Android, not iOS.

          Note: The *note Python UTF-8 Mode: 659. affects encodings used
          for 'cmd' and pipe contents.

          ‘popen()’ is a simple wrapper around *note subprocess.Popen:
          199.  Use ‘subprocess.Popen’ or *note subprocess.run(): ba4.
          to control options like encodings.

 -- Function: os.posix_spawn (path, argv, env, *, file_actions=None,
          setpgroup=None, resetids=False, setsid=False, setsigmask=(),
          setsigdef=(), scheduler=None)

     Wraps the ‘posix_spawn()’ C library API for use from Python.

     Most users should use *note subprocess.run(): ba4. instead of
     ‘posix_spawn()’.

     The positional-only arguments 'path', 'args', and 'env' are similar
     to *note execve(): 113d.  'env' is allowed to be ‘None’, in which
     case current process’ environment is used.

     The 'path' parameter is the path to the executable file.  The
     'path' should contain a directory.  Use *note posix_spawnp(): 15b4.
     to pass an executable file without directory.

     The 'file_actions' argument may be a sequence of tuples describing
     actions to take on specific file descriptors in the child process
     between the C library implementation’s ‘fork()’ and ‘exec()’ steps.
     The first item in each tuple must be one of the three type
     indicator listed below describing the remaining tuple elements:

      -- Data: os.POSIX_SPAWN_OPEN

          (‘os.POSIX_SPAWN_OPEN’, 'fd', 'path', 'flags', 'mode')

          Performs ‘os.dup2(os.open(path, flags, mode), fd)’.

      -- Data: os.POSIX_SPAWN_CLOSE

          (‘os.POSIX_SPAWN_CLOSE’, 'fd')

          Performs ‘os.close(fd)’.

      -- Data: os.POSIX_SPAWN_DUP2

          (‘os.POSIX_SPAWN_DUP2’, 'fd', 'new_fd')

          Performs ‘os.dup2(fd, new_fd)’.

      -- Data: os.POSIX_SPAWN_CLOSEFROM

          (‘os.POSIX_SPAWN_CLOSEFROM’, 'fd')

          Performs ‘os.closerange(fd, INF)’.

     These tuples correspond to the C library
     ‘posix_spawn_file_actions_addopen()’,
     ‘posix_spawn_file_actions_addclose()’,
     ‘posix_spawn_file_actions_adddup2()’, and
     ‘posix_spawn_file_actions_addclosefrom_np()’ API calls used to
     prepare for the ‘posix_spawn()’ call itself.

     The 'setpgroup' argument will set the process group of the child to
     the value specified.  If the value specified is 0, the child’s
     process group ID will be made the same as its process ID. If the
     value of 'setpgroup' is not set, the child will inherit the
     parent’s process group ID. This argument corresponds to the C
     library ‘POSIX_SPAWN_SETPGROUP’ flag.

     If the 'resetids' argument is ‘True’ it will reset the effective
     UID and GID of the child to the real UID and GID of the parent
     process.  If the argument is ‘False’, then the child retains the
     effective UID and GID of the parent.  In either case, if the
     set-user-ID and set-group-ID permission bits are enabled on the
     executable file, their effect will override the setting of the
     effective UID and GID. This argument corresponds to the C library
     ‘POSIX_SPAWN_RESETIDS’ flag.

     If the 'setsid' argument is ‘True’, it will create a new session ID
     for ‘posix_spawn’.  'setsid' requires ‘POSIX_SPAWN_SETSID’ or
     ‘POSIX_SPAWN_SETSID_NP’ flag.  Otherwise, *note
     NotImplementedError: 228. is raised.

     The 'setsigmask' argument will set the signal mask to the signal
     set specified.  If the parameter is not used, then the child
     inherits the parent’s signal mask.  This argument corresponds to
     the C library ‘POSIX_SPAWN_SETSIGMASK’ flag.

     The 'sigdef' argument will reset the disposition of all signals in
     the set specified.  This argument corresponds to the C library
     ‘POSIX_SPAWN_SETSIGDEF’ flag.

     The 'scheduler' argument must be a tuple containing the (optional)
     scheduler policy and an instance of *note sched_param: 16a8. with
     the scheduler parameters.  A value of ‘None’ in the place of the
     scheduler policy indicates that is not being provided.  This
     argument is a combination of the C library
     ‘POSIX_SPAWN_SETSCHEDPARAM’ and ‘POSIX_SPAWN_SETSCHEDULER’ flags.

     Raises an *note auditing event: 1a15. ‘os.posix_spawn’ with
     arguments ‘path’, ‘argv’, ‘env’.

     Added in version 3.8.

     Changed in version 3.13: 'env' parameter accepts ‘None’.
     ‘os.POSIX_SPAWN_CLOSEFROM’ is available on platforms where
     ‘posix_spawn_file_actions_addclosefrom_np()’ exists.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.posix_spawnp (path, argv, env, *, file_actions=None,
          setpgroup=None, resetids=False, setsid=False, setsigmask=(),
          setsigdef=(), scheduler=None)

     Wraps the ‘posix_spawnp()’ C library API for use from Python.

     Similar to *note posix_spawn(): 220. except that the system
     searches for the 'executable' file in the list of directories
     specified by the ‘PATH’ environment variable (in the same way as
     for ‘execvp(3)’).

     Raises an *note auditing event: 1a15. ‘os.posix_spawn’ with
     arguments ‘path’, ‘argv’, ‘env’.

     Added in version 3.8.

     *note Availability: 1ef7.: POSIX, not WASI, not Android, not iOS.

     See *note posix_spawn(): 220. documentation.

 -- Function: os.register_at_fork (*, before=None, after_in_parent=None,
          after_in_child=None)

     Register callables to be executed when a new child process is
     forked using *note os.fork(): 197. or similar process cloning APIs.
     The parameters are optional and keyword-only.  Each specifies a
     different call point.

        * 'before' is a function called before forking a child process.

        * 'after_in_parent' is a function called from the parent process
          after forking a child process.

        * 'after_in_child' is a function called from the child process.

     These calls are only made if control is expected to return to the
     Python interpreter.  A typical *note subprocess: d6. launch will
     not trigger them as the child is not going to re-enter the
     interpreter.

     Functions registered for execution before forking are called in
     reverse registration order.  Functions registered for execution
     after forking (either in the parent or in the child) are called in
     registration order.

     Note that ‘fork()’ calls made by third-party C code may not call
     those functions, unless it explicitly calls *note
     PyOS_BeforeFork(): bde, *note PyOS_AfterFork_Parent(): bdf. and
     *note PyOS_AfterFork_Child(): 3fe.

     There is no way to unregister a function.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     Added in version 3.7.

 -- Function: os.spawnl (mode, path, ...)
 -- Function: os.spawnle (mode, path, ..., env)
 -- Function: os.spawnlp (mode, file, ...)
 -- Function: os.spawnlpe (mode, file, ..., env)
 -- Function: os.spawnv (mode, path, args)
 -- Function: os.spawnve (mode, path, args, env)
 -- Function: os.spawnvp (mode, file, args)
 -- Function: os.spawnvpe (mode, file, args, env)

     Execute the program 'path' in a new process.

     (Note that the *note subprocess: d6. module provides more powerful
     facilities for spawning new processes and retrieving their results;
     using that module is preferable to using these functions.  Check
     especially the *note Replacing Older Functions with the subprocess
     Module: 11cc. section.)

     If 'mode' is *note P_NOWAIT: 2dd6, this function returns the
     process id of the new process; if 'mode' is *note P_WAIT: 2dd7,
     returns the process’s exit code if it exits normally, or ‘-signal’,
     where 'signal' is the signal that killed the process.  On Windows,
     the process id will actually be the process handle, so can be used
     with the *note waitpid(): dc8. function.

     Note on VxWorks, this function doesn’t return ‘-signal’ when the
     new process is killed.  Instead it raises OSError exception.

     The “l” and “v” variants of the ‘spawn*’ functions differ in how
     command-line arguments are passed.  The “l” variants are perhaps
     the easiest to work with if the number of parameters is fixed when
     the code is written; the individual parameters simply become
     additional parameters to the ‘spawnl*()’ functions.  The “v”
     variants are good when the number of parameters is variable, with
     the arguments being passed in a list or tuple as the 'args'
     parameter.  In either case, the arguments to the child process must
     start with the name of the command being run.

     The variants which include a second “p” near the end (‘spawnlp()’,
     ‘spawnlpe()’, ‘spawnvp()’, and ‘spawnvpe()’) will use the ‘PATH’
     environment variable to locate the program 'file'.  When the
     environment is being replaced (using one of the ‘spawn*e’ variants,
     discussed in the next paragraph), the new environment is used as
     the source of the ‘PATH’ variable.  The other variants, ‘spawnl()’,
     ‘spawnle()’, ‘spawnv()’, and ‘spawnve()’, will not use the ‘PATH’
     variable to locate the executable; 'path' must contain an
     appropriate absolute or relative path.

     For ‘spawnle()’, ‘spawnlpe()’, ‘spawnve()’, and ‘spawnvpe()’ (note
     that these all end in “e”), the 'env' parameter must be a mapping
     which is used to define the environment variables for the new
     process (they are used instead of the current process’
     environment); the functions ‘spawnl()’, ‘spawnlp()’, ‘spawnv()’,
     and ‘spawnvp()’ all cause the new process to inherit the
     environment of the current process.  Note that keys and values in
     the 'env' dictionary must be strings; invalid keys or values will
     cause the function to fail, with a return value of ‘127’.

     As an example, the following calls to ‘spawnlp()’ and ‘spawnvpe()’
     are equivalent:

          import os
          os.spawnlp(os.P_WAIT, 'cp', 'cp', 'index.html', '/dev/null')

          L = ['cp', 'index.html', '/dev/null']
          os.spawnvpe(os.P_WAIT, 'cp', L, os.environ)

     Raises an *note auditing event: 1a15. ‘os.spawn’ with arguments
     ‘mode’, ‘path’, ‘args’, ‘env’.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not Android,
     not iOS.

     ‘spawnlp()’, ‘spawnlpe()’, ‘spawnvp()’ and ‘spawnvpe()’ are not
     available on Windows.  ‘spawnle()’ and ‘spawnve()’ are not
     thread-safe on Windows; we advise you to use the *note subprocess:
     d6. module instead.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Data: os.P_NOWAIT
 -- Data: os.P_NOWAITO

     Possible values for the 'mode' parameter to the *note spawn*: 1842.
     family of functions.  If either of these values is given, the
     ‘spawn*’ functions will return as soon as the new process has been
     created, with the process id as the return value.

     *note Availability: 1ef7.: Unix, Windows.

 -- Data: os.P_WAIT

     Possible value for the 'mode' parameter to the *note spawn*: 1842.
     family of functions.  If this is given as 'mode', the ‘spawn*’
     functions will not return until the new process has run to
     completion and will return the exit code of the process the run is
     successful, or ‘-signal’ if a signal kills the process.

     *note Availability: 1ef7.: Unix, Windows.

 -- Data: os.P_DETACH
 -- Data: os.P_OVERLAY

     Possible values for the 'mode' parameter to the *note spawn*: 1842.
     family of functions.  These are less portable than those listed
     above.  *note P_DETACH: 2dd9. is similar to *note P_NOWAIT: 2dd6,
     but the new process is detached from the console of the calling
     process.  If *note P_OVERLAY: 2dda. is used, the current process
     will be replaced; the ‘spawn*’ function will not return.

     *note Availability: 1ef7.: Windows.

 -- Function: os.startfile (path[, operation][, arguments][, cwd][,
          show_cmd])

     Start a file with its associated application.

     When 'operation' is not specified, this acts like double-clicking
     the file in Windows Explorer, or giving the file name as an
     argument to the ‘start’ command from the interactive command shell:
     the file is opened with whatever application (if any) its extension
     is associated.

     When another 'operation' is given, it must be a “command verb” that
     specifies what should be done with the file.  Common verbs
     documented by Microsoft are ‘'open'’, ‘'print'’ and ‘'edit'’ (to be
     used on files) as well as ‘'explore'’ and ‘'find'’ (to be used on
     directories).

     When launching an application, specify 'arguments' to be passed as
     a single string.  This argument may have no effect when using this
     function to launch a document.

     The default working directory is inherited, but may be overridden
     by the 'cwd' argument.  This should be an absolute path.  A
     relative 'path' will be resolved against this argument.

     Use 'show_cmd' to override the default window style.  Whether this
     has any effect will depend on the application being launched.
     Values are integers as supported by the Win32 ‘ShellExecute()’
     function.

     ‘startfile()’ returns as soon as the associated application is
     launched.  There is no option to wait for the application to close,
     and no way to retrieve the application’s exit status.  The 'path'
     parameter is relative to the current directory or 'cwd'.  If you
     want to use an absolute path, make sure the first character is not
     a slash (‘'/'’) Use *note pathlib: a4. or the *note
     os.path.normpath(): 1363. function to ensure that paths are
     properly encoded for Win32.

     To reduce interpreter startup overhead, the Win32 ‘ShellExecute()’
     function is not resolved until this function is first called.  If
     the function cannot be resolved, *note NotImplementedError: 228.
     will be raised.

     Raises an *note auditing event: 1a15. ‘os.startfile’ with arguments
     ‘path’, ‘operation’.

     Raises an *note auditing event: 1a15. ‘os.startfile/2’ with
     arguments ‘path’, ‘operation’, ‘arguments’, ‘cwd’, ‘show_cmd’.

     *note Availability: 1ef7.: Windows.

     Changed in version 3.10: Added the 'arguments', 'cwd' and
     'show_cmd' arguments, and the ‘os.startfile/2’ audit event.

 -- Function: os.system (command)

     Execute the command (a string) in a subshell.  This is implemented
     by calling the Standard C function ‘system()’, and has the same
     limitations.  Changes to *note sys.stdin: 540, etc.  are not
     reflected in the environment of the executed command.  If 'command'
     generates any output, it will be sent to the interpreter standard
     output stream.  The C standard does not specify the meaning of the
     return value of the C function, so the return value of the Python
     function is system-dependent.

     On Unix, the return value is the exit status of the process encoded
     in the format specified for *note wait(): dc6.

     On Windows, the return value is that returned by the system shell
     after running 'command'.  The shell is given by the Windows
     environment variable ‘COMSPEC’: it is usually ‘cmd.exe’, which
     returns the exit status of the command run; on systems using a
     non-native shell, consult your shell documentation.

     The *note subprocess: d6. module provides more powerful facilities
     for spawning new processes and retrieving their results; using that
     module is preferable to using this function.  See the *note
     Replacing Older Functions with the subprocess Module: 11cc. section
     in the ‘subprocess’ documentation for some helpful recipes.

     On Unix, *note waitstatus_to_exitcode(): 926. can be used to
     convert the result (exit status) into an exit code.  On Windows,
     the result is directly the exit code.

     Raises an *note auditing event: 1a15. ‘os.system’ with argument
     ‘command’.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not Android,
     not iOS.

 -- Function: os.times ()

     Returns the current global process times.  The return value is an
     object with five attributes:

        * ‘user’ - user time

        * ‘system’ - system time

        * ‘children_user’ - user time of all child processes

        * ‘children_system’ - system time of all child processes

        * ‘elapsed’ - elapsed real time since a fixed point in the past

     For backwards compatibility, this object also behaves like a
     five-tuple containing ‘user’, ‘system’, ‘children_user’,
     ‘children_system’, and ‘elapsed’ in that order.

     See the Unix manual page ‘times(2)(5)’ and times(3)(6) manual page
     on Unix or the GetProcessTimes MSDN(7) on Windows.  On Windows,
     only ‘user’ and ‘system’ are known; the other attributes are zero.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.3: Return type changed from a tuple to a
     tuple-like object with named attributes.

 -- Function: os.wait ()

     Wait for completion of a child process, and return a tuple
     containing its pid and exit status indication: a 16-bit number,
     whose low byte is the signal number that killed the process, and
     whose high byte is the exit status (if the signal number is zero);
     the high bit of the low byte is set if a core file was produced.

     If there are no children that could be waited for, *note
     ChildProcessError: 1096. is raised.

     *note waitstatus_to_exitcode(): 926. can be used to convert the
     exit status into an exit code.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     See also
     ........

     The other ‘wait*()’ functions documented below can be used to wait
     for the completion of a specific child process and have more
     options.  *note waitpid(): dc8. is the only one also available on
     Windows.

 -- Function: os.waitid (idtype, id, options, /)

     Wait for the completion of a child process.

     'idtype' can be *note P_PID: 2ddb, *note P_PGID: 2ddc, *note P_ALL:
     2ddd, or (on Linux) *note P_PIDFD: 923.  The interpretation of 'id'
     depends on it; see their individual descriptions.

     'options' is an OR combination of flags.  At least one of *note
     WEXITED: 2dde, *note WSTOPPED: 2ddf. or *note WCONTINUED: 2de0. is
     required; *note WNOHANG: 2de1. and *note WNOWAIT: 2de2. are
     additional optional flags.

     The return value is an object representing the data contained in
     the ‘siginfo_t’ structure with the following attributes:

        * ‘si_pid’ (process ID)

        * ‘si_uid’ (real user ID of the child)

        * ‘si_signo’ (always *note SIGCHLD: 2de3.)

        * ‘si_status’ (the exit status or signal number, depending on
          ‘si_code’)

        * ‘si_code’ (see *note CLD_EXITED: 2de4. for possible values)

     If *note WNOHANG: 2de1. is specified and there are no matching
     children in the requested state, ‘None’ is returned.  Otherwise, if
     there are no matching children that could be waited for, *note
     ChildProcessError: 1096. is raised.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     Added in version 3.3.

     Changed in version 3.13: This function is now available on macOS as
     well.

 -- Function: os.waitpid (pid, options, /)

     The details of this function differ on Unix and Windows.

     On Unix: Wait for completion of a child process given by process id
     'pid', and return a tuple containing its process id and exit status
     indication (encoded as for *note wait(): dc6.).  The semantics of
     the call are affected by the value of the integer 'options', which
     should be ‘0’ for normal operation.

     If 'pid' is greater than ‘0’, ‘waitpid()’ requests status
     information for that specific process.  If 'pid' is ‘0’, the
     request is for the status of any child in the process group of the
     current process.  If 'pid' is ‘-1’, the request pertains to any
     child of the current process.  If 'pid' is less than ‘-1’, status
     is requested for any process in the process group ‘-pid’ (the
     absolute value of 'pid').

     'options' is an OR combination of flags.  If it contains *note
     WNOHANG: 2de1. and there are no matching children in the requested
     state, ‘(0, 0)’ is returned.  Otherwise, if there are no matching
     children that could be waited for, *note ChildProcessError: 1096.
     is raised.  Other options that can be used are *note WUNTRACED:
     2de5. and *note WCONTINUED: 2de0.

     On Windows: Wait for completion of a process given by process
     handle 'pid', and return a tuple containing 'pid', and its exit
     status shifted left by 8 bits (shifting makes cross-platform use of
     the function easier).  A 'pid' less than or equal to ‘0’ has no
     special meaning on Windows, and raises an exception.  The value of
     integer 'options' has no effect.  'pid' can refer to any process
     whose id is known, not necessarily a child process.  The *note
     spawn*: 1842. functions called with *note P_NOWAIT: 2dd6. return
     suitable process handles.

     *note waitstatus_to_exitcode(): 926. can be used to convert the
     exit status into an exit code.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not Android,
     not iOS.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the function now
     retries the system call instead of raising an *note
     InterruptedError: db6. exception (see PEP 475(8) for the
     rationale).

 -- Function: os.wait3 (options)

     Similar to *note waitpid(): dc8, except no process id argument is
     given and a 3-element tuple containing the child’s process id, exit
     status indication, and resource usage information is returned.
     Refer to *note resource.getrusage(): 147f. for details on resource
     usage information.  The 'options' argument is the same as that
     provided to ‘waitpid()’ and *note wait4(): dc5.

     *note waitstatus_to_exitcode(): 926. can be used to convert the
     exit status into an exitcode.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.wait4 (pid, options)

     Similar to *note waitpid(): dc8, except a 3-element tuple,
     containing the child’s process id, exit status indication, and
     resource usage information is returned.  Refer to *note
     resource.getrusage(): 147f. for details on resource usage
     information.  The arguments to ‘wait4()’ are the same as those
     provided to ‘waitpid()’.

     *note waitstatus_to_exitcode(): 926. can be used to convert the
     exit status into an exitcode.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Data: os.P_PID
 -- Data: os.P_PGID
 -- Data: os.P_ALL
 -- Data: os.P_PIDFD

     These are the possible values for 'idtype' in *note waitid(): dc7.
     They affect how 'id' is interpreted:

        * ‘P_PID’ - wait for the child whose PID is 'id'.

        * ‘P_PGID’ - wait for any child whose progress group ID is 'id'.

        * ‘P_ALL’ - wait for any child; 'id' is ignored.

        * ‘P_PIDFD’ - wait for the child identified by the file
          descriptor 'id' (a process file descriptor created with *note
          pidfd_open(): 47d.).

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

          Note: ‘P_PIDFD’ is only available on Linux >= 5.4.

     Added in version 3.3.

     Added in version 3.9: The ‘P_PIDFD’ constant.

 -- Data: os.WCONTINUED

     This 'options' flag for *note waitpid(): dc8, *note wait3(): dc4,
     *note wait4(): dc5, and *note waitid(): dc7. causes child processes
     to be reported if they have been continued from a job control stop
     since they were last reported.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Data: os.WEXITED

     This 'options' flag for *note waitid(): dc7. causes child processes
     that have terminated to be reported.

     The other ‘wait*’ functions always report children that have
     terminated, so this option is not available for them.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     Added in version 3.3.

 -- Data: os.WSTOPPED

     This 'options' flag for *note waitid(): dc7. causes child processes
     that have been stopped by the delivery of a signal to be reported.

     This option is not available for the other ‘wait*’ functions.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     Added in version 3.3.

 -- Data: os.WUNTRACED

     This 'options' flag for *note waitpid(): dc8, *note wait3(): dc4,
     and *note wait4(): dc5. causes child processes to also be reported
     if they have been stopped but their current state has not been
     reported since they were stopped.

     This option is not available for *note waitid(): dc7.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Data: os.WNOHANG

     This 'options' flag causes *note waitpid(): dc8, *note wait3():
     dc4, *note wait4(): dc5, and *note waitid(): dc7. to return right
     away if no child process status is available immediately.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Data: os.WNOWAIT

     This 'options' flag causes *note waitid(): dc7. to leave the child
     in a waitable state, so that a later ‘wait*()’ call can be used to
     retrieve the child status information again.

     This option is not available for the other ‘wait*’ functions.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Data: os.CLD_EXITED
 -- Data: os.CLD_KILLED
 -- Data: os.CLD_DUMPED
 -- Data: os.CLD_TRAPPED
 -- Data: os.CLD_STOPPED
 -- Data: os.CLD_CONTINUED

     These are the possible values for ‘si_code’ in the result returned
     by *note waitid(): dc7.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

     Added in version 3.3.

     Changed in version 3.9: Added ‘CLD_KILLED’ and ‘CLD_STOPPED’
     values.

 -- Function: os.waitstatus_to_exitcode (status)

     Convert a wait status to an exit code.

     On Unix:

        * If the process exited normally (if ‘WIFEXITED(status)’ is
          true), return the process exit status (return
          ‘WEXITSTATUS(status)’): result greater than or equal to 0.

        * If the process was terminated by a signal (if
          ‘WIFSIGNALED(status)’ is true), return ‘-signum’ where
          'signum' is the number of the signal that caused the process
          to terminate (return ‘-WTERMSIG(status)’): result less than 0.

        * Otherwise, raise a *note ValueError: 202.

     On Windows, return 'status' shifted right by 8 bits.

     On Unix, if the process is being traced or if *note waitpid(): dc8.
     was called with *note WUNTRACED: 2de5. option, the caller must
     first check if ‘WIFSTOPPED(status)’ is true.  This function must
     not be called if ‘WIFSTOPPED(status)’ is true.

     See also
     ........

     *note WIFEXITED(): 2de9, *note WEXITSTATUS(): 2dea, *note
     WIFSIGNALED(): 2deb, *note WTERMSIG(): 2dec, *note WIFSTOPPED():
     2ded, *note WSTOPSIG(): 2dee. functions.

     *note Availability: 1ef7.: Unix, Windows, not WASI, not Android,
     not iOS.

     Added in version 3.9.

The following functions take a process status code as returned by *note
system(): 14ac, *note wait(): dc6, or *note waitpid(): dc8. as a
parameter.  They may be used to determine the disposition of a process.

 -- Function: os.WCOREDUMP (status, /)

     Return ‘True’ if a core dump was generated for the process,
     otherwise return ‘False’.

     This function should be employed only if *note WIFSIGNALED(): 2deb.
     is true.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WIFCONTINUED (status)

     Return ‘True’ if a stopped child has been resumed by delivery of
     *note SIGCONT: 2df1. (if the process has been continued from a job
     control stop), otherwise return ‘False’.

     See *note WCONTINUED: 2de0. option.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WIFSTOPPED (status)

     Return ‘True’ if the process was stopped by delivery of a signal,
     otherwise return ‘False’.

     ‘WIFSTOPPED()’ only returns ‘True’ if the *note waitpid(): dc8.
     call was done using *note WUNTRACED: 2de5. option or when the
     process is being traced (see ‘ptrace(2)(9)’).

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WIFSIGNALED (status)

     Return ‘True’ if the process was terminated by a signal, otherwise
     return ‘False’.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WIFEXITED (status)

     Return ‘True’ if the process exited terminated normally, that is,
     by calling ‘exit()’ or ‘_exit()’, or by returning from ‘main()’;
     otherwise return ‘False’.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WEXITSTATUS (status)

     Return the process exit status.

     This function should be employed only if *note WIFEXITED(): 2de9.
     is true.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WSTOPSIG (status)

     Return the signal which caused the process to stop.

     This function should be employed only if *note WIFSTOPPED(): 2ded.
     is true.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

 -- Function: os.WTERMSIG (status)

     Return the number of the signal that caused the process to
     terminate.

     This function should be employed only if *note WIFSIGNALED(): 2deb.
     is true.

     *note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

   ---------- Footnotes ----------

   (1) https://msdn.microsoft.com/44228cf2-6306-466c-8f16-f513cd3ba8b5

   (2) https://discuss.python.org/t/33555

   (3) https://manpages.debian.org/pidfd_open(2)

   (4) https://manpages.debian.org/waitid(2)

   (5) https://manpages.debian.org/times(2)

   (6) https://man.freebsd.org/cgi/man.cgi?time(3)

   (7) 
https://docs.microsoft.com/windows/win32/api/processthreadsapi/nf-processthreadsapi-getprocesstimes

   (8) https://peps.python.org/pep-0475/

   (9) https://manpages.debian.org/ptrace(2)


File: python.info,  Node: Interface to the scheduler,  Next: Miscellaneous System Information,  Prev: Process Management,  Up: os — Miscellaneous operating system interfaces

5.16.1.12 Interface to the scheduler
....................................

These functions control how a process is allocated CPU time by the
operating system.  They are only available on some Unix platforms.  For
more detailed information, consult your Unix manpages.

Added in version 3.3.

The following scheduling policies are exposed if they are supported by
the operating system.

 -- Data: os.SCHED_OTHER

     The default scheduling policy.

 -- Data: os.SCHED_BATCH

     Scheduling policy for CPU-intensive processes that tries to
     preserve interactivity on the rest of the computer.

 -- Data: os.SCHED_IDLE

     Scheduling policy for extremely low priority background tasks.

 -- Data: os.SCHED_SPORADIC

     Scheduling policy for sporadic server programs.

 -- Data: os.SCHED_FIFO

     A First In First Out scheduling policy.

 -- Data: os.SCHED_RR

     A round-robin scheduling policy.

 -- Data: os.SCHED_RESET_ON_FORK

     This flag can be OR’ed with any other scheduling policy.  When a
     process with this flag set forks, its child’s scheduling policy and
     priority are reset to the default.

 -- Class: os.sched_param (sched_priority)

     This class represents tunable scheduling parameters used in *note
     sched_setparam(): 1153, *note sched_setscheduler(): 1154, and *note
     sched_getparam(): 114f.  It is immutable.

     At the moment, there is only one possible parameter:

      -- Attribute: sched_priority

          The scheduling priority for a scheduling policy.

 -- Function: os.sched_get_priority_min (policy)

     Get the minimum priority value for 'policy'.  'policy' is one of
     the scheduling policy constants above.

 -- Function: os.sched_get_priority_max (policy)

     Get the maximum priority value for 'policy'.  'policy' is one of
     the scheduling policy constants above.

 -- Function: os.sched_setscheduler (pid, policy, param, /)

     Set the scheduling policy for the process with PID 'pid'.  A 'pid'
     of 0 means the calling process.  'policy' is one of the scheduling
     policy constants above.  'param' is a *note sched_param: 16a8.
     instance.

 -- Function: os.sched_getscheduler (pid, /)

     Return the scheduling policy for the process with PID 'pid'.  A
     'pid' of 0 means the calling process.  The result is one of the
     scheduling policy constants above.

 -- Function: os.sched_setparam (pid, param, /)

     Set the scheduling parameters for the process with PID 'pid'.  A
     'pid' of 0 means the calling process.  'param' is a *note
     sched_param: 16a8. instance.

 -- Function: os.sched_getparam (pid, /)

     Return the scheduling parameters as a *note sched_param: 16a8.
     instance for the process with PID 'pid'.  A 'pid' of 0 means the
     calling process.

 -- Function: os.sched_rr_get_interval (pid, /)

     Return the round-robin quantum in seconds for the process with PID
     'pid'.  A 'pid' of 0 means the calling process.

 -- Function: os.sched_yield ()

     Voluntarily relinquish the CPU. See ‘sched_yield(2)(1)’ for
     details.

 -- Function: os.sched_setaffinity (pid, mask, /)

     Restrict the process with PID 'pid' (or the current process if
     zero) to a set of CPUs.  'mask' is an iterable of integers
     representing the set of CPUs to which the process should be
     restricted.

 -- Function: os.sched_getaffinity (pid, /)

     Return the set of CPUs the process with PID 'pid' is restricted to.

     If 'pid' is zero, return the set of CPUs the calling thread of the
     current process is restricted to.

     See also the *note process_cpu_count(): 1c4. function.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/sched_yield(2)


File: python.info,  Node: Miscellaneous System Information,  Next: Random numbers<2>,  Prev: Interface to the scheduler,  Up: os — Miscellaneous operating system interfaces

5.16.1.13 Miscellaneous System Information
..........................................

 -- Function: os.confstr (name, /)

     Return string-valued system configuration values.  'name' specifies
     the configuration value to retrieve; it may be a string which is
     the name of a defined system value; these names are specified in a
     number of standards (POSIX, Unix 95, Unix 98, and others).  Some
     platforms define additional names as well.  The names known to the
     host operating system are given as the keys of the ‘confstr_names’
     dictionary.  For configuration variables not included in that
     mapping, passing an integer for 'name' is also accepted.

     If the configuration value specified by 'name' isn’t defined,
     ‘None’ is returned.

     If 'name' is a string and is not known, *note ValueError: 202. is
     raised.  If a specific value for 'name' is not supported by the
     host system, even if it is included in ‘confstr_names’, an *note
     OSError: 41a. is raised with *note errno.EINVAL: 1b7f. for the
     error number.

     *note Availability: 1ef7.: Unix.

 -- Data: os.confstr_names

     Dictionary mapping names accepted by *note confstr(): 166f. to the
     integer values defined for those names by the host operating
     system.  This can be used to determine the set of names known to
     the system.

     *note Availability: 1ef7.: Unix.

 -- Function: os.cpu_count ()

     Return the number of logical CPUs in the 'system'.  Returns ‘None’
     if undetermined.

     The *note process_cpu_count(): 1c4. function can be used to get the
     number of logical CPUs usable by the calling thread of the 'current
     process'.

     Added in version 3.4.

     Changed in version 3.13: If *note -X cpu_count: 176. is given or
     *note PYTHON_CPU_COUNT: 210. is set, ‘cpu_count()’ returns the
     override value 'n'.

 -- Function: os.getloadavg ()

     Return the number of processes in the system run queue averaged
     over the last 1, 5, and 15 minutes or raises *note OSError: 41a. if
     the load average was unobtainable.

     *note Availability: 1ef7.: Unix.

 -- Function: os.process_cpu_count ()

     Get the number of logical CPUs usable by the calling thread of the
     'current process'.  Returns ‘None’ if undetermined.  It can be less
     than *note cpu_count(): 1c5. depending on the CPU affinity.

     The *note cpu_count(): 1c5. function can be used to get the number
     of logical CPUs in the 'system'.

     If *note -X cpu_count: 176. is given or *note PYTHON_CPU_COUNT:
     210. is set, ‘process_cpu_count()’ returns the override value 'n'.

     See also the *note sched_getaffinity(): 114e. function.

     Added in version 3.13.

 -- Function: os.sysconf (name, /)

     Return integer-valued system configuration values.  If the
     configuration value specified by 'name' isn’t defined, ‘-1’ is
     returned.  The comments regarding the 'name' parameter for *note
     confstr(): 166f. apply here as well; the dictionary that provides
     information on the known names is given by ‘sysconf_names’.

     *note Availability: 1ef7.: Unix.

 -- Data: os.sysconf_names

     Dictionary mapping names accepted by *note sysconf(): 1670. to the
     integer values defined for those names by the host operating
     system.  This can be used to determine the set of names known to
     the system.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.11: Add ‘'SC_MINSIGSTKSZ'’ name.

The following data values are used to support path manipulation
operations.  These are defined for all platforms.

Higher-level operations on pathnames are defined in the *note os.path:
a2. module.

 -- Data: os.curdir

     The constant string used by the operating system to refer to the
     current directory.  This is ‘'.'’ for Windows and POSIX. Also
     available via *note os.path: a2.

 -- Data: os.pardir

     The constant string used by the operating system to refer to the
     parent directory.  This is ‘'..'’ for Windows and POSIX. Also
     available via *note os.path: a2.

 -- Data: os.sep

     The character used by the operating system to separate pathname
     components.  This is ‘'/'’ for POSIX and ‘'\\'’ for Windows.  Note
     that knowing this is not sufficient to be able to parse or
     concatenate pathnames — use *note os.path.split(): 29a6. and *note
     os.path.join(): 173c. — but it is occasionally useful.  Also
     available via *note os.path: a2.

 -- Data: os.altsep

     An alternative character used by the operating system to separate
     pathname components, or ‘None’ if only one separator character
     exists.  This is set to ‘'/'’ on Windows systems where ‘sep’ is a
     backslash.  Also available via *note os.path: a2.

 -- Data: os.extsep

     The character which separates the base filename from the extension;
     for example, the ‘'.'’ in ‘os.py’.  Also available via *note
     os.path: a2.

 -- Data: os.pathsep

     The character conventionally used by the operating system to
     separate search path components (as in ‘PATH’), such as ‘':'’ for
     POSIX or ‘';'’ for Windows.  Also available via *note os.path: a2.

 -- Data: os.defpath

     The default search path used by *note exec*p*: 2db2. and *note
     spawn*p*: 1842. if the environment doesn’t have a ‘'PATH'’ key.
     Also available via *note os.path: a2.

 -- Data: os.linesep

     The string used to separate (or, rather, terminate) lines on the
     current platform.  This may be a single character, such as ‘'\n'’
     for POSIX, or multiple characters, for example, ‘'\r\n'’ for
     Windows.  Do not use 'os.linesep' as a line terminator when writing
     files opened in text mode (the default); use a single ‘'\n'’
     instead, on all platforms.

 -- Data: os.devnull

     The file path of the null device.  For example: ‘'/dev/null'’ for
     POSIX, ‘'nul'’ for Windows.  Also available via *note os.path: a2.

 -- Data: os.RTLD_LAZY
 -- Data: os.RTLD_NOW
 -- Data: os.RTLD_GLOBAL
 -- Data: os.RTLD_LOCAL
 -- Data: os.RTLD_NODELETE
 -- Data: os.RTLD_NOLOAD
 -- Data: os.RTLD_DEEPBIND

     Flags for use with the *note setdlopenflags(): 1163. and *note
     getdlopenflags(): 155e. functions.  See the Unix manual page
     ‘dlopen(3)(1)’ for what the different flags mean.

     Added in version 3.3.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/dlopen(3)


File: python.info,  Node: Random numbers<2>,  Prev: Miscellaneous System Information,  Up: os — Miscellaneous operating system interfaces

5.16.1.14 Random numbers
........................

 -- Function: os.getrandom (size, flags=0)

     Get up to 'size' random bytes.  The function can return less bytes
     than requested.

     These bytes can be used to seed user-space random number generators
     or for cryptographic purposes.

     ‘getrandom()’ relies on entropy gathered from device drivers and
     other sources of environmental noise.  Unnecessarily reading large
     quantities of data will have a negative impact on other users of
     the ‘/dev/random’ and ‘/dev/urandom’ devices.

     The flags argument is a bit mask that can contain zero or more of
     the following values ORed together: *note os.GRND_RANDOM: 2e02. and
     *note GRND_NONBLOCK: 2e03.

     See also the Linux getrandom() manual page(1).

     *note Availability: 1ef7.: Linux >= 3.17.

     Added in version 3.6.

 -- Function: os.urandom (size, /)

     Return a bytestring of 'size' random bytes suitable for
     cryptographic use.

     This function returns random bytes from an OS-specific randomness
     source.  The returned data should be unpredictable enough for
     cryptographic applications, though its exact quality depends on the
     OS implementation.

     On Linux, if the ‘getrandom()’ syscall is available, it is used in
     blocking mode: block until the system urandom entropy pool is
     initialized (128 bits of entropy are collected by the kernel).  See
     the PEP 524(2) for the rationale.  On Linux, the *note getrandom():
     ce3. function can be used to get random bytes in non-blocking mode
     (using the *note GRND_NONBLOCK: 2e03. flag) or to poll until the
     system urandom entropy pool is initialized.

     On a Unix-like system, random bytes are read from the
     ‘/dev/urandom’ device.  If the ‘/dev/urandom’ device is not
     available or not readable, the *note NotImplementedError: 228.
     exception is raised.

     On Windows, it will use ‘BCryptGenRandom()’.

     See also
     ........

     The *note secrets: c0. module provides higher level functions.  For
     an easy-to-use interface to the random number generator provided by
     your platform, please see *note random.SystemRandom: 28aa.

     Changed in version 3.5: On Linux 3.17 and newer, the ‘getrandom()’
     syscall is now used when available.  On OpenBSD 5.6 and newer, the
     C ‘getentropy()’ function is now used.  These functions avoid the
     usage of an internal file descriptor.

     Changed in version 3.5.2: On Linux, if the ‘getrandom()’ syscall
     blocks (the urandom entropy pool is not initialized yet), fall back
     on reading ‘/dev/urandom’.

     Changed in version 3.6: On Linux, ‘getrandom()’ is now used in
     blocking mode to increase the security.

     Changed in version 3.11: On Windows, ‘BCryptGenRandom()’ is used
     instead of ‘CryptGenRandom()’ which is deprecated.

 -- Data: os.GRND_NONBLOCK

     By default, when reading from ‘/dev/random’, *note getrandom():
     ce3. blocks if no random bytes are available, and when reading from
     ‘/dev/urandom’, it blocks if the entropy pool has not yet been
     initialized.

     If the ‘GRND_NONBLOCK’ flag is set, then *note getrandom(): ce3.
     does not block in these cases, but instead immediately raises *note
     BlockingIOError: 1095.

     Added in version 3.6.

 -- Data: os.GRND_RANDOM

     If this bit is set, then random bytes are drawn from the
     ‘/dev/random’ pool instead of the ‘/dev/urandom’ pool.

     Added in version 3.6.

   ---------- Footnotes ----------

   (1) https://man7.org/linux/man-pages/man2/getrandom.2.html

   (2) https://peps.python.org/pep-0524/


File: python.info,  Node: io — Core tools for working with streams,  Next: time — Time access and conversions,  Prev: os — Miscellaneous operating system interfaces,  Up: Generic Operating System Services

5.16.2 ‘io’ — Core tools for working with streams
-------------------------------------------------

'Source code:' Lib/io.py(1)

__________________________________________________________________

* Menu:

* Overview: Overview<2>.
* Text Encoding::
* High-level Module Interface::
* Class hierarchy::
* Performance: Performance<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/io.py


File: python.info,  Node: Overview<2>,  Next: Text Encoding,  Up: io — Core tools for working with streams

5.16.2.1 Overview
.................

The ‘io’ module provides Python’s main facilities for dealing with
various types of I/O. There are three main types of I/O: 'text I/O',
'binary I/O' and 'raw I/O'. These are generic categories, and various
backing stores can be used for each of them.  A concrete object
belonging to any of these categories is called a *note file object:
1208.  Other common terms are 'stream' and 'file-like object'.

Independent of its category, each concrete stream object will also have
various capabilities: it can be read-only, write-only, or read-write.
It can also allow arbitrary random access (seeking forwards or backwards
to any location), or only sequential access (for example in the case of
a socket or pipe).

All streams are careful about the type of data you give to them.  For
example giving a *note str: 44f. object to the ‘write()’ method of a
binary stream will raise a *note TypeError: 2c3.  So will giving a *note
bytes: 1c2. object to the ‘write()’ method of a text stream.

Changed in version 3.3: Operations that used to raise *note IOError:
1090. now raise *note OSError: 41a, since ‘IOError’ is now an alias of
‘OSError’.

* Menu:

* Text I/O::
* Binary I/O::
* Raw I/O::


File: python.info,  Node: Text I/O,  Next: Binary I/O,  Up: Overview<2>

5.16.2.2 Text I/O
.................

Text I/O expects and produces *note str: 44f. objects.  This means that
whenever the backing store is natively made of bytes (such as in the
case of a file), encoding and decoding of data is made transparently as
well as optional translation of platform-specific newline characters.

The easiest way to create a text stream is with *note open(): 51f,
optionally specifying an encoding:

     f = open("myfile.txt", "r", encoding="utf-8")

In-memory text streams are also available as *note StringIO: f5e.
objects:

     f = io.StringIO("some initial text data")

The text stream API is described in detail in the documentation of *note
TextIOBase: 698.


File: python.info,  Node: Binary I/O,  Next: Raw I/O,  Prev: Text I/O,  Up: Overview<2>

5.16.2.3 Binary I/O
...................

Binary I/O (also called 'buffered I/O') expects *note bytes-like
objects: d55. and produces *note bytes: 1c2. objects.  No encoding,
decoding, or newline translation is performed.  This category of streams
can be used for all kinds of non-text data, and also when manual control
over the handling of text data is desired.

The easiest way to create a binary stream is with *note open(): 51f.
with ‘'b'’ in the mode string:

     f = open("myfile.jpg", "rb")

In-memory binary streams are also available as *note BytesIO: ed8.
objects:

     f = io.BytesIO(b"some initial binary data: \x00\x01")

The binary stream API is described in detail in the docs of *note
BufferedIOBase: 697.

Other library modules may provide additional ways to create text or
binary streams.  See *note socket.socket.makefile(): 11e3. for example.


File: python.info,  Node: Raw I/O,  Prev: Binary I/O,  Up: Overview<2>

5.16.2.4 Raw I/O
................

Raw I/O (also called 'unbuffered I/O') is generally used as a low-level
building-block for binary and text streams; it is rarely useful to
directly manipulate a raw stream from user code.  Nevertheless, you can
create a raw stream by opening a file in binary mode with buffering
disabled:

     f = open("myfile.jpg", "rb", buffering=0)

The raw stream API is described in detail in the docs of *note
RawIOBase: 1114.


File: python.info,  Node: Text Encoding,  Next: High-level Module Interface,  Prev: Overview<2>,  Up: io — Core tools for working with streams

5.16.2.5 Text Encoding
......................

The default encoding of *note TextIOWrapper: 7bf. and *note open(): 51f.
is locale-specific (*note locale.getencoding(): 2dc.).

However, many developers forget to specify the encoding when opening
text files encoded in UTF-8 (e.g.  JSON, TOML, Markdown, etc…) since
most Unix platforms use UTF-8 locale by default.  This causes bugs
because the locale encoding is not UTF-8 for most Windows users.  For
example:

     # May not work on Windows when non-ASCII characters in the file.
     with open("README.md") as f:
         long_description = f.read()

Accordingly, it is highly recommended that you specify the encoding
explicitly when opening text files.  If you want to use UTF-8, pass
‘encoding="utf-8"’.  To use the current locale encoding,
‘encoding="locale"’ is supported since Python 3.10.

See also
........

*note Python UTF-8 Mode: 659.

     Python UTF-8 Mode can be used to change the default encoding to
     UTF-8 from locale-specific encoding.

PEP 686(1)

     Python 3.15 will make *note Python UTF-8 Mode: 659. default.

* Menu:

* Opt-in EncodingWarning::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0686/


File: python.info,  Node: Opt-in EncodingWarning,  Up: Text Encoding

5.16.2.6 Opt-in EncodingWarning
...............................

Added in version 3.10: See PEP 597(1) for more details.

To find where the default locale encoding is used, you can enable the
*note -X warn_default_encoding: 176. command line option or set the
*note PYTHONWARNDEFAULTENCODING: 7c0. environment variable, which will
emit an *note EncodingWarning: 1ee5. when the default encoding is used.

If you are providing an API that uses *note open(): 51f. or *note
TextIOWrapper: 7bf. and passes ‘encoding=None’ as a parameter, you can
use *note text_encoding(): 17d6. so that callers of the API will emit an
*note EncodingWarning: 1ee5. if they don’t pass an ‘encoding’.  However,
please consider using UTF-8 by default (i.e.  ‘encoding="utf-8"’) for
new APIs.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0597/


File: python.info,  Node: High-level Module Interface,  Next: Class hierarchy,  Prev: Text Encoding,  Up: io — Core tools for working with streams

5.16.2.7 High-level Module Interface
....................................

 -- Data: io.DEFAULT_BUFFER_SIZE

     An int containing the default buffer size used by the module’s
     buffered I/O classes.  *note open(): 51f. uses the file’s blksize
     (as obtained by *note os.stat(): 4a3.) if possible.

 -- Function: io.open (file, mode='r', buffering=-1, encoding=None,
          errors=None, newline=None, closefd=True, opener=None)

     This is an alias for the builtin ‘open()’ function.

     This function raises an *note auditing event: 1a15. ‘open’ with
     arguments 'path', 'mode' and 'flags'.  The 'mode' and 'flags'
     arguments may have been modified or inferred from the original
     call.

 -- Function: io.open_code (path)

     Opens the provided file with mode ‘'rb'’.  This function should be
     used when the intent is to treat the contents as executable code.

     'path' should be a *note str: 44f. and an absolute path.

     The behavior of this function may be overridden by an earlier call
     to the *note PyFile_SetOpenCodeHook(): 183a.  However, assuming
     that 'path' is a *note str: 44f. and an absolute path,
     ‘open_code(path)’ should always behave the same as ‘open(path,
     'rb')’.  Overriding the behavior is intended for additional
     validation or preprocessing of the file.

     Added in version 3.8.

 -- Function: io.text_encoding (encoding, stacklevel=2, /)

     This is a helper function for callables that use *note open(): 51f.
     or *note TextIOWrapper: 7bf. and have an ‘encoding=None’ parameter.

     This function returns 'encoding' if it is not ‘None’.  Otherwise,
     it returns ‘"locale"’ or ‘"utf-8"’ depending on *note UTF-8 Mode:
     659.

     This function emits an *note EncodingWarning: 1ee5. if *note
     sys.flags.warn_default_encoding: 68f. is true and 'encoding' is
     ‘None’.  'stacklevel' specifies where the warning is emitted.  For
     example:

          def read_text(path, encoding=None):
              encoding = io.text_encoding(encoding)  # stacklevel=2
              with open(path, encoding) as f:
                  return f.read()

     In this example, an *note EncodingWarning: 1ee5. is emitted for the
     caller of ‘read_text()’.

     See *note Text Encoding: 7c1. for more information.

     Added in version 3.10.

     Changed in version 3.11: ‘text_encoding()’ returns “utf-8” when
     UTF-8 mode is enabled and 'encoding' is ‘None’.

 -- Exception: io.BlockingIOError

     This is a compatibility alias for the builtin ‘BlockingIOError’
     exception.

 -- Exception: io.UnsupportedOperation

     An exception inheriting *note OSError: 41a. and *note ValueError:
     202. that is raised when an unsupported operation is called on a
     stream.

See also
........

*note sys: d9.

     contains the standard IO streams: *note sys.stdin: 540, *note
     sys.stdout: aec, and *note sys.stderr: 943.


File: python.info,  Node: Class hierarchy,  Next: Performance<3>,  Prev: High-level Module Interface,  Up: io — Core tools for working with streams

5.16.2.8 Class hierarchy
........................

The implementation of I/O streams is organized as a hierarchy of
classes.  First *note abstract base classes: 11fa. (ABCs), which are
used to specify the various categories of streams, then concrete classes
providing the standard stream implementations.

     Note: The abstract base classes also provide default
     implementations of some methods in order to help implementation of
     concrete stream classes.  For example, *note BufferedIOBase: 697.
     provides unoptimized implementations of ‘readinto()’ and
     ‘readline()’.

At the top of the I/O hierarchy is the abstract base class *note IOBase:
1f5.  It defines the basic interface to a stream.  Note, however, that
there is no separation between reading and writing to streams;
implementations are allowed to raise *note UnsupportedOperation: 1b28.
if they do not support a given operation.

The *note RawIOBase: 1114. ABC extends *note IOBase: 1f5.  It deals with
the reading and writing of bytes to a stream.  *note FileIO: 1359.
subclasses ‘RawIOBase’ to provide an interface to files in the machine’s
file system.

The *note BufferedIOBase: 697. ABC extends *note IOBase: 1f5.  It deals
with buffering on a raw binary stream (*note RawIOBase: 1114.).  Its
subclasses, *note BufferedWriter: 13fe, *note BufferedReader: 1253, and
*note BufferedRWPair: 1400. buffer raw binary streams that are writable,
readable, and both readable and writable, respectively.  *note
BufferedRandom: 13ff. provides a buffered interface to seekable streams.
Another ‘BufferedIOBase’ subclass, *note BytesIO: ed8, is a stream of
in-memory bytes.

The *note TextIOBase: 698. ABC extends *note IOBase: 1f5.  It deals with
streams whose bytes represent text, and handles encoding and decoding to
and from strings.  *note TextIOWrapper: 7bf, which extends ‘TextIOBase’,
is a buffered text interface to a buffered raw stream (*note
BufferedIOBase: 697.).  Finally, *note StringIO: f5e. is an in-memory
stream for text.

Argument names are not part of the specification, and only the arguments
of *note open(): 51f. are intended to be used as keyword arguments.

The following table summarizes the ABCs provided by the ‘io’ module:

ABC                           Inherits               Stub Methods                 Mixin Methods and Properties
                                                                                  
-----------------------------------------------------------------------------------------------------------------------------------------
                                                                                  
*note IOBase: 1f5.                                   ‘fileno’, ‘seek’, and        ‘close’, ‘closed’, ‘__enter__’, ‘__exit__’, ‘flush’,
                                                     ‘truncate’                   ‘isatty’, ‘__iter__’, ‘__next__’, ‘readable’,
                                                                                  ‘readline’, ‘readlines’, ‘seekable’, ‘tell’,
                                                                                  ‘writable’, and ‘writelines’
                                                                                  
                                                                                  
*note RawIOBase: 1114.        *note IOBase: 1f5.     ‘readinto’ and ‘write’       Inherited *note IOBase: 1f5. methods, ‘read’, and
                                                                                  ‘readall’
                                                                                  
                                                                                  
*note BufferedIOBase: 697.    *note IOBase: 1f5.     ‘detach’, ‘read’, ‘read1’,   Inherited *note IOBase: 1f5. methods, ‘readinto’,
                                                     and ‘write’                  and ‘readinto1’
                                                                                  
                                                                                  
*note TextIOBase: 698.        *note IOBase: 1f5.     ‘detach’, ‘read’,            Inherited *note IOBase: 1f5. methods, ‘encoding’,
                                                     ‘readline’, and ‘write’      ‘errors’, and ‘newlines’
                                                                                  

* Menu:

* I/O Base Classes::
* Raw File I/O::
* Buffered Streams::
* Text I/O: Text I/O<2>.


File: python.info,  Node: I/O Base Classes,  Next: Raw File I/O,  Up: Class hierarchy

5.16.2.9 I/O Base Classes
.........................

 -- Class: io.IOBase

     The abstract base class for all I/O classes.

     This class provides empty abstract implementations for many methods
     that derived classes can override selectively; the default
     implementations represent a file that cannot be read, written or
     seeked.

     Even though ‘IOBase’ does not declare ‘read()’ or ‘write()’ because
     their signatures will vary, implementations and clients should
     consider those methods part of the interface.  Also,
     implementations may raise a *note ValueError: 202. (or *note
     UnsupportedOperation: 1b28.) when operations they do not support
     are called.

     The basic type used for binary data read from or written to a file
     is *note bytes: 1c2.  Other *note bytes-like objects: d55. are
     accepted as method arguments too.  Text I/O classes work with *note
     str: 44f. data.

     Note that calling any method (even inquiries) on a closed stream is
     undefined.  Implementations may raise *note ValueError: 202. in
     this case.

     ‘IOBase’ (and its subclasses) supports the iterator protocol,
     meaning that an ‘IOBase’ object can be iterated over yielding the
     lines in a stream.  Lines are defined slightly differently
     depending on whether the stream is a binary stream (yielding
     bytes), or a text stream (yielding character strings).  See *note
     readline(): 1373. below.

     ‘IOBase’ is also a context manager and therefore supports the *note
     with: 5d5. statement.  In this example, 'file' is closed after the
     ‘with’ statement’s suite is finished—even if an exception occurs:

          with open('spam.txt', 'w') as file:
              file.write('Spam and eggs!')

     ‘IOBase’ provides these data attributes and methods:

      -- Method: close ()

          Flush and close this stream.  This method has no effect if the
          file is already closed.  Once the file is closed, any
          operation on the file (e.g.  reading or writing) will raise a
          *note ValueError: 202.

          As a convenience, it is allowed to call this method more than
          once; only the first call, however, will have an effect.

      -- Attribute: closed

          ‘True’ if the stream is closed.

      -- Method: fileno ()

          Return the underlying file descriptor (an integer) of the
          stream if it exists.  An *note OSError: 41a. is raised if the
          IO object does not use a file descriptor.

      -- Method: flush ()

          Flush the write buffers of the stream if applicable.  This
          does nothing for read-only and non-blocking streams.

      -- Method: isatty ()

          Return ‘True’ if the stream is interactive (i.e., connected to
          a terminal/tty device).

      -- Method: readable ()

          Return ‘True’ if the stream can be read from.  If ‘False’,
          ‘read()’ will raise *note OSError: 41a.

      -- Method: readline (size=-1, /)

          Read and return one line from the stream.  If 'size' is
          specified, at most 'size' bytes will be read.

          The line terminator is always ‘b'\n'’ for binary files; for
          text files, the 'newline' argument to *note open(): 51f. can
          be used to select the line terminator(s) recognized.

      -- Method: readlines (hint=-1, /)

          Read and return a list of lines from the stream.  'hint' can
          be specified to control the number of lines read: no more
          lines will be read if the total size (in bytes/characters) of
          all lines so far exceeds 'hint'.

          'hint' values of ‘0’ or less, as well as ‘None’, are treated
          as no hint.

          Note that it’s already possible to iterate on file objects
          using ‘for line in file: ...’ without calling
          ‘file.readlines()’.

      -- Method: seek (offset, whence=os.SEEK_SET, /)

          Change the stream position to the given byte 'offset',
          interpreted relative to the position indicated by 'whence',
          and return the new absolute position.  Values for 'whence'
          are:

             * *note os.SEEK_SET: 12d4. or ‘0’ – start of the stream
               (the default); 'offset' should be zero or positive

             * *note os.SEEK_CUR: 12d5. or ‘1’ – current stream
               position; 'offset' may be negative

             * *note os.SEEK_END: 12d6. or ‘2’ – end of the stream;
               'offset' is usually negative

          Added in version 3.1: The ‘SEEK_*’ constants.

          Added in version 3.3: Some operating systems could support
          additional values, like *note os.SEEK_HOLE: 2d3f. or *note
          os.SEEK_DATA: 2d40.  The valid values for a file could depend
          on it being open in text or binary mode.

      -- Method: seekable ()

          Return ‘True’ if the stream supports random access.  If
          ‘False’, *note seek(): 12d3, *note tell(): 13f9. and *note
          truncate(): 135a. will raise *note OSError: 41a.

      -- Method: tell ()

          Return the current stream position.

      -- Method: truncate (size=None, /)

          Resize the stream to the given 'size' in bytes (or the current
          position if 'size' is not specified).  The current stream
          position isn’t changed.  This resizing can extend or reduce
          the current file size.  In case of extension, the contents of
          the new file area depend on the platform (on most systems,
          additional bytes are zero-filled).  The new file size is
          returned.

          Changed in version 3.5: Windows will now zero-fill files when
          extending.

      -- Method: writable ()

          Return ‘True’ if the stream supports writing.  If ‘False’,
          ‘write()’ and *note truncate(): 135a. will raise *note
          OSError: 41a.

      -- Method: writelines (lines, /)

          Write a list of lines to the stream.  Line separators are not
          added, so it is usual for each of the lines provided to have a
          line separator at the end.

      -- Method: __del__ ()

          Prepare for object destruction.  ‘IOBase’ provides a default
          implementation of this method that calls the instance’s *note
          close(): 1f6. method.

 -- Class: io.RawIOBase

     Base class for raw binary streams.  It inherits from *note IOBase:
     1f5.

     Raw binary streams typically provide low-level access to an
     underlying OS device or API, and do not try to encapsulate it in
     high-level primitives (this functionality is done at a higher-level
     in buffered binary streams and text streams, described later in
     this page).

     ‘RawIOBase’ provides these methods in addition to those from *note
     IOBase: 1f5.:

      -- Method: read (size=-1, /)

          Read up to 'size' bytes from the object and return them.  As a
          convenience, if 'size' is unspecified or -1, all bytes until
          EOF are returned.  Otherwise, only one system call is ever
          made.  Fewer than 'size' bytes may be returned if the
          operating system call returns fewer than 'size' bytes.

          If 0 bytes are returned, and 'size' was not 0, this indicates
          end of file.  If the object is in non-blocking mode and no
          bytes are available, ‘None’ is returned.

          The default implementation defers to *note readall(): 2e12.
          and *note readinto(): e4f.

      -- Method: readall ()

          Read and return all the bytes from the stream until EOF, using
          multiple calls to the stream if necessary.

      -- Method: readinto (b, /)

          Read bytes into a pre-allocated, writable *note bytes-like
          object: d55. 'b', and return the number of bytes read.  For
          example, 'b' might be a *note bytearray: 2ea.  If the object
          is in non-blocking mode and no bytes are available, ‘None’ is
          returned.

      -- Method: write (b, /)

          Write the given *note bytes-like object: d55, 'b', to the
          underlying raw stream, and return the number of bytes written.
          This can be less than the length of 'b' in bytes, depending on
          specifics of the underlying raw stream, and especially if it
          is in non-blocking mode.  ‘None’ is returned if the raw stream
          is set not to block and no single byte could be readily
          written to it.  The caller may release or mutate 'b' after
          this method returns, so the implementation should only access
          'b' during the method call.

 -- Class: io.BufferedIOBase

     Base class for binary streams that support some kind of buffering.
     It inherits from *note IOBase: 1f5.

     The main difference with *note RawIOBase: 1114. is that methods
     *note read(): 1372, *note readinto(): 2e13. and *note write(): d02.
     will try (respectively) to read as much input as requested or to
     emit all provided data.

     In addition, if the underlying raw stream is in non-blocking mode,
     when the system returns would block *note write(): d02. will raise
     *note BlockingIOError: 1095. with *note
     BlockingIOError.characters_written: 245b. and *note read(): 1372.
     will return data read so far or ‘None’ if no data is available.

     Besides, the *note read(): 1372. method does not have a default
     implementation that defers to *note readinto(): 2e13.

     A typical ‘BufferedIOBase’ implementation should not inherit from a
     *note RawIOBase: 1114. implementation, but wrap one, like *note
     BufferedWriter: 13fe. and *note BufferedReader: 1253. do.

     ‘BufferedIOBase’ provides or overrides these data attributes and
     methods in addition to those from *note IOBase: 1f5.:

      -- Attribute: raw

          The underlying raw stream (a *note RawIOBase: 1114. instance)
          that ‘BufferedIOBase’ deals with.  This is not part of the
          ‘BufferedIOBase’ API and may not exist on some
          implementations.

      -- Method: detach ()

          Separate the underlying raw stream from the buffer and return
          it.

          After the raw stream has been detached, the buffer is in an
          unusable state.

          Some buffers, like *note BytesIO: ed8, do not have the concept
          of a single raw stream to return from this method.  They raise
          *note UnsupportedOperation: 1b28.

          Added in version 3.1.

      -- Method: read (size=-1, /)

          Read and return up to 'size' bytes.  If the argument is
          omitted, ‘None’, or negative read as much as possible.

          Fewer bytes may be returned than requested.  An empty *note
          bytes: 1c2. object is returned if the stream is already at
          EOF.  More than one read may be made and calls may be retried
          if specific errors are encountered, see *note os.read(): dc3.
          and PEP 475(1) for more details.  Less than size bytes being
          returned does not imply that EOF is imminent.

          When reading as much as possible the default implementation
          will use ‘raw.readall’ if available (which should implement
          *note RawIOBase.readall(): 2e12.), otherwise will read in a
          loop until read returns ‘None’, an empty *note bytes: 1c2, or
          a non-retryable error.  For most streams this is to EOF, but
          for non-blocking streams more data may become available.

               Note: When the underlying raw stream is non-blocking,
               implementations may either raise *note BlockingIOError:
               1095. or return ‘None’ if no data is available.  ‘io’
               implementations return ‘None’.

      -- Method: read1 (size=-1, /)

          Read and return up to 'size' bytes, calling *note readinto():
          e4f. which may retry if *note EINTR: db5. is encountered per
          PEP 475(2).  If 'size' is ‘-1’ or not provided, the
          implementation will choose an arbitrary value for 'size'.

               Note: When the underlying raw stream is non-blocking,
               implementations may either raise *note BlockingIOError:
               1095. or return ‘None’ if no data is available.  ‘io’
               implementations return ‘None’.

      -- Method: readinto (b, /)

          Read bytes into a pre-allocated, writable *note bytes-like
          object: d55. 'b' and return the number of bytes read.  For
          example, 'b' might be a *note bytearray: 2ea.

          Like *note read(): 1372, multiple reads may be issued to the
          underlying raw stream, unless the latter is interactive.

          A *note BlockingIOError: 1095. is raised if the underlying raw
          stream is in non blocking-mode, and has no data available at
          the moment.

      -- Method: readinto1 (b, /)

          Read bytes into a pre-allocated, writable *note bytes-like
          object: d55. 'b', using at most one call to the underlying raw
          stream’s *note read(): e4e. (or *note readinto(): e4f.)
          method.  Return the number of bytes read.

          A *note BlockingIOError: 1095. is raised if the underlying raw
          stream is in non blocking-mode, and has no data available at
          the moment.

          Added in version 3.5.

      -- Method: write (b, /)

          Write the given *note bytes-like object: d55, 'b', and return
          the number of bytes written (always equal to the length of 'b'
          in bytes, since if the write fails an *note OSError: 41a. will
          be raised).  Depending on the actual implementation, these
          bytes may be readily written to the underlying stream, or held
          in a buffer for performance and latency reasons.

          When in non-blocking mode, a *note BlockingIOError: 1095. is
          raised if the data needed to be written to the raw stream but
          it couldn’t accept all the data without blocking.

          The caller may release or mutate 'b' after this method
          returns, so the implementation should only access 'b' during
          the method call.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://peps.python.org/pep-0475/


File: python.info,  Node: Raw File I/O,  Next: Buffered Streams,  Prev: I/O Base Classes,  Up: Class hierarchy

5.16.2.10 Raw File I/O
......................

 -- Class: io.FileIO (name, mode='r', closefd=True, opener=None)

     A raw binary stream representing an OS-level file containing bytes
     data.  It inherits from *note RawIOBase: 1114.

     The 'name' can be one of two things:

        * a character string or *note bytes: 1c2. object representing
          the path to the file which will be opened.  In this case
          closefd must be ‘True’ (the default) otherwise an error will
          be raised.

        * an integer representing the number of an existing OS-level
          file descriptor to which the resulting ‘FileIO’ object will
          give access.  When the FileIO object is closed this fd will be
          closed as well, unless 'closefd' is set to ‘False’.

     The 'mode' can be ‘'r'’, ‘'w'’, ‘'x'’ or ‘'a'’ for reading
     (default), writing, exclusive creation or appending.  The file will
     be created if it doesn’t exist when opened for writing or
     appending; it will be truncated when opened for writing.  *note
     FileExistsError: 105b. will be raised if it already exists when
     opened for creating.  Opening a file for creating implies writing,
     so this mode behaves in a similar way to ‘'w'’.  Add a ‘'+'’ to the
     mode to allow simultaneous reading and writing.

     The *note read(): e4e. (when called with a positive argument),
     *note readinto(): e4f. and *note write(): 13f8. methods on this
     class will only make one system call.

     A custom opener can be used by passing a callable as 'opener'.  The
     underlying file descriptor for the file object is then obtained by
     calling 'opener' with ('name', 'flags').  'opener' must return an
     open file descriptor (passing *note os.open: dc0. as 'opener'
     results in functionality similar to passing ‘None’).

     The newly created file is *note non-inheritable: f30.

     See the *note open(): 51f. built-in function for examples on using
     the 'opener' parameter.

     Changed in version 3.3: The 'opener' parameter was added.  The
     ‘'x'’ mode was added.

     Changed in version 3.4: The file is now non-inheritable.

     ‘FileIO’ provides these data attributes in addition to those from
     *note RawIOBase: 1114. and *note IOBase: 1f5.:

      -- Attribute: mode

          The mode as given in the constructor.

      -- Attribute: name

          The file name.  This is the file descriptor of the file when
          no name is given in the constructor.


File: python.info,  Node: Buffered Streams,  Next: Text I/O<2>,  Prev: Raw File I/O,  Up: Class hierarchy

5.16.2.11 Buffered Streams
..........................

Buffered I/O streams provide a higher-level interface to an I/O device
than raw I/O does.

 -- Class: io.BytesIO (initial_bytes=b'')

     A binary stream using an in-memory bytes buffer.  It inherits from
     *note BufferedIOBase: 697.  The buffer is discarded when the *note
     close(): 1f6. method is called.

     The optional argument 'initial_bytes' is a *note bytes-like object:
     d55. that contains initial data.

     ‘BytesIO’ provides or overrides these methods in addition to those
     from *note BufferedIOBase: 697. and *note IOBase: 1f5.:

      -- Method: getbuffer ()

          Return a readable and writable view over the contents of the
          buffer without copying them.  Also, mutating the view will
          transparently update the contents of the buffer:

               >>> b = io.BytesIO(b"abcdef")
               >>> view = b.getbuffer()
               >>> view[2:4] = b"56"
               >>> b.getvalue()
               b'ab56ef'

               Note: As long as the view exists, the ‘BytesIO’ object
               cannot be resized or closed.

          Added in version 3.2.

      -- Method: getvalue ()

          Return *note bytes: 1c2. containing the entire contents of the
          buffer.

      -- Method: read1 (size=-1, /)

          In ‘BytesIO’, this is the same as *note read(): 1372.

          Changed in version 3.7: The 'size' argument is now optional.

      -- Method: readinto1 (b, /)

          In ‘BytesIO’, this is the same as *note readinto(): 2e13.

          Added in version 3.5.

 -- Class: io.BufferedReader (raw, buffer_size=DEFAULT_BUFFER_SIZE)

     A buffered binary stream providing higher-level access to a
     readable, non seekable *note RawIOBase: 1114. raw binary stream.
     It inherits from *note BufferedIOBase: 697.

     When reading data from this object, a larger amount of data may be
     requested from the underlying raw stream, and kept in an internal
     buffer.  The buffered data can then be returned directly on
     subsequent reads.

     The constructor creates a ‘BufferedReader’ for the given readable
     'raw' stream and 'buffer_size'.  If 'buffer_size' is omitted, *note
     DEFAULT_BUFFER_SIZE: 17d7. is used.

     ‘BufferedReader’ provides or overrides these methods in addition to
     those from *note BufferedIOBase: 697. and *note IOBase: 1f5.:

      -- Method: peek (size=0, /)

          Return bytes from the stream without advancing the position.
          The number of bytes returned may be less or more than
          requested.  If the underlying raw stream is non-blocking and
          the operation would block, returns empty bytes.

      -- Method: read (size=-1, /)

          In ‘BufferedReader’ this is the same as *note
          io.BufferedIOBase.read(): 1372.

      -- Method: read1 (size=-1, /)

          In ‘BufferedReader’ this is the same as *note
          io.BufferedIOBase.read1(): 2b54.

          Changed in version 3.7: The 'size' argument is now optional.

 -- Class: io.BufferedWriter (raw, buffer_size=DEFAULT_BUFFER_SIZE)

     A buffered binary stream providing higher-level access to a
     writeable, non seekable *note RawIOBase: 1114. raw binary stream.
     It inherits from *note BufferedIOBase: 697.

     When writing to this object, data is normally placed into an
     internal buffer.  The buffer will be written out to the underlying
     *note RawIOBase: 1114. object under various conditions, including:

        * when the buffer gets too small for all pending data;

        * when *note flush(): 2e1c. is called;

        * when a *note seek(): 12d3. is requested (for *note
          BufferedRandom: 13ff. objects);

        * when the ‘BufferedWriter’ object is closed or destroyed.

     The constructor creates a ‘BufferedWriter’ for the given writeable
     'raw' stream.  If the 'buffer_size' is not given, it defaults to
     *note DEFAULT_BUFFER_SIZE: 17d7.

     ‘BufferedWriter’ provides or overrides these methods in addition to
     those from *note BufferedIOBase: 697. and *note IOBase: 1f5.:

      -- Method: flush ()

          Force bytes held in the buffer into the raw stream.  A *note
          BlockingIOError: 1095. should be raised if the raw stream
          blocks.

      -- Method: write (b, /)

          Write the *note bytes-like object: d55, 'b', and return the
          number of bytes written.  When in non-blocking mode, a *note
          BlockingIOError: 1095. with *note
          BlockingIOError.characters_written: 245b. set is raised if the
          buffer needs to be written out but the raw stream blocks.

 -- Class: io.BufferedRandom (raw, buffer_size=DEFAULT_BUFFER_SIZE)

     A buffered binary stream providing higher-level access to a
     seekable *note RawIOBase: 1114. raw binary stream.  It inherits
     from *note BufferedReader: 1253. and *note BufferedWriter: 13fe.

     The constructor creates a reader and writer for a seekable raw
     stream, given in the first argument.  If the 'buffer_size' is
     omitted it defaults to *note DEFAULT_BUFFER_SIZE: 17d7.

     ‘BufferedRandom’ is capable of anything *note BufferedReader: 1253.
     or *note BufferedWriter: 13fe. can do.  In addition, *note seek():
     12d3. and *note tell(): 13f9. are guaranteed to be implemented.

 -- Class: io.BufferedRWPair (reader, writer,
          buffer_size=DEFAULT_BUFFER_SIZE, /)

     A buffered binary stream providing higher-level access to two non
     seekable *note RawIOBase: 1114. raw binary streams—one readable,
     the other writeable.  It inherits from *note BufferedIOBase: 697.

     'reader' and 'writer' are *note RawIOBase: 1114. objects that are
     readable and writeable respectively.  If the 'buffer_size' is
     omitted it defaults to *note DEFAULT_BUFFER_SIZE: 17d7.

     ‘BufferedRWPair’ implements all of *note BufferedIOBase: 697.'s
     methods except for *note detach(): 2b65, which raises *note
     UnsupportedOperation: 1b28.

          Warning: ‘BufferedRWPair’ does not attempt to synchronize
          accesses to its underlying raw streams.  You should not pass
          it the same object as reader and writer; use *note
          BufferedRandom: 13ff. instead.


File: python.info,  Node: Text I/O<2>,  Prev: Buffered Streams,  Up: Class hierarchy

5.16.2.12 Text I/O
..................

 -- Class: io.TextIOBase

     Base class for text streams.  This class provides a character and
     line based interface to stream I/O. It inherits from *note IOBase:
     1f5.

     ‘TextIOBase’ provides or overrides these data attributes and
     methods in addition to those from *note IOBase: 1f5.:

      -- Attribute: encoding

          The name of the encoding used to decode the stream’s bytes
          into strings, and to encode strings into bytes.

      -- Attribute: errors

          The error setting of the decoder or encoder.

      -- Attribute: newlines

          A string, a tuple of strings, or ‘None’, indicating the
          newlines translated so far.  Depending on the implementation
          and the initial constructor flags, this may not be available.

      -- Attribute: buffer

          The underlying binary buffer (a *note BufferedIOBase: 697. or
          *note RawIOBase: 1114. instance) that ‘TextIOBase’ deals with.
          This is not part of the ‘TextIOBase’ API and may not exist in
          some implementations.

      -- Method: detach ()

          Separate the underlying binary buffer from the ‘TextIOBase’
          and return it.

          After the underlying buffer has been detached, the
          ‘TextIOBase’ is in an unusable state.

          Some ‘TextIOBase’ implementations, like *note StringIO: f5e,
          may not have the concept of an underlying buffer and calling
          this method will raise *note UnsupportedOperation: 1b28.

          Added in version 3.1.

      -- Method: read (size=-1, /)

          Read and return at most 'size' characters from the stream as a
          single *note str: 44f.  If 'size' is negative or ‘None’, reads
          until EOF.

      -- Method: readline (size=-1, /)

          Read until newline or EOF and return a single *note str: 44f.
          If the stream is already at EOF, an empty string is returned.

          If 'size' is specified, at most 'size' characters will be
          read.

      -- Method: seek (offset, whence=SEEK_SET, /)

          Change the stream position to the given 'offset'.  Behaviour
          depends on the 'whence' parameter.  The default value for
          'whence' is ‘SEEK_SET’.

             * ‘SEEK_SET’ or ‘0’: seek from the start of the stream (the
               default); 'offset' must either be a number returned by
               *note TextIOBase.tell(): 2e22, or zero.  Any other
               'offset' value produces undefined behaviour.

             * ‘SEEK_CUR’ or ‘1’: “seek” to the current position;
               'offset' must be zero, which is a no-operation (all other
               values are unsupported).

             * ‘SEEK_END’ or ‘2’: seek to the end of the stream;
               'offset' must be zero (all other values are unsupported).

          Return the new absolute position as an opaque number.

          Added in version 3.1: The ‘SEEK_*’ constants.

      -- Method: tell ()

          Return the current stream position as an opaque number.  The
          number does not usually represent a number of bytes in the
          underlying binary storage.

      -- Method: write (s, /)

          Write the string 's' to the stream and return the number of
          characters written.

 -- Class: io.TextIOWrapper (buffer, encoding=None, errors=None,
          newline=None, line_buffering=False, write_through=False)

     A buffered text stream providing higher-level access to a *note
     BufferedIOBase: 697. buffered binary stream.  It inherits from
     *note TextIOBase: 698.

     'encoding' gives the name of the encoding that the stream will be
     decoded or encoded with.  In *note UTF-8 Mode: 659, this defaults
     to UTF-8.  Otherwise, it defaults to *note locale.getencoding():
     2dc.  ‘encoding="locale"’ can be used to specify the current
     locale’s encoding explicitly.  See *note Text Encoding: 7c1. for
     more information.

     'errors' is an optional string that specifies how encoding and
     decoding errors are to be handled.  Pass ‘'strict'’ to raise a
     *note ValueError: 202. exception if there is an encoding error (the
     default of ‘None’ has the same effect), or pass ‘'ignore'’ to
     ignore errors.  (Note that ignoring encoding errors can lead to
     data loss.)  ‘'replace'’ causes a replacement marker (such as
     ‘'?'’) to be inserted where there is malformed data.
     ‘'backslashreplace'’ causes malformed data to be replaced by a
     backslashed escape sequence.  When writing, ‘'xmlcharrefreplace'’
     (replace with the appropriate XML character reference) or
     ‘'namereplace'’ (replace with ‘\N{...}’ escape sequences) can be
     used.  Any other error handling name that has been registered with
     *note codecs.register_error(): 14ea. is also valid.

     'newline' controls how line endings are handled.  It can be ‘None’,
     ‘''’, ‘'\n'’, ‘'\r'’, and ‘'\r\n'’.  It works as follows:

        * When reading input from the stream, if 'newline' is ‘None’,
          *note universal newlines: d62. mode is enabled.  Lines in the
          input can end in ‘'\n'’, ‘'\r'’, or ‘'\r\n'’, and these are
          translated into ‘'\n'’ before being returned to the caller.
          If 'newline' is ‘''’, universal newlines mode is enabled, but
          line endings are returned to the caller untranslated.  If
          'newline' has any of the other legal values, input lines are
          only terminated by the given string, and the line ending is
          returned to the caller untranslated.

        * When writing output to the stream, if 'newline' is ‘None’, any
          ‘'\n'’ characters written are translated to the system default
          line separator, *note os.linesep: 2334.  If 'newline' is ‘''’
          or ‘'\n'’, no translation takes place.  If 'newline' is any of
          the other legal values, any ‘'\n'’ characters written are
          translated to the given string.

     If 'line_buffering' is ‘True’, *note flush(): 2db9. is implied when
     a call to write contains a newline character or a carriage return.

     If 'write_through' is ‘True’, calls to *note write(): d02. are
     guaranteed not to be buffered: any data written on the
     ‘TextIOWrapper’ object is immediately handled to its underlying
     binary 'buffer'.

     Changed in version 3.3: The 'write_through' argument has been
     added.

     Changed in version 3.3: The default 'encoding' is now
     ‘locale.getpreferredencoding(False)’ instead of
     ‘locale.getpreferredencoding()’.  Don’t change temporary the locale
     encoding using *note locale.setlocale(): 2db, use the current
     locale encoding instead of the user preferred encoding.

     Changed in version 3.10: The 'encoding' argument now supports the
     ‘"locale"’ dummy encoding name.

     ‘TextIOWrapper’ provides these data attributes and methods in
     addition to those from *note TextIOBase: 698. and *note IOBase:
     1f5.:

      -- Attribute: line_buffering

          Whether line buffering is enabled.

      -- Attribute: write_through

          Whether writes are passed immediately to the underlying binary
          buffer.

          Added in version 3.7.

      -- Method: reconfigure (*, encoding=None, errors=None,
               newline=None, line_buffering=None, write_through=None)

          Reconfigure this text stream using new settings for
          'encoding', 'errors', 'newline', 'line_buffering' and
          'write_through'.

          Parameters not specified keep current settings, except
          ‘errors='strict'’ is used when 'encoding' is specified but
          'errors' is not specified.

          It is not possible to change the encoding or newline if some
          data has already been read from the stream.  On the other
          hand, changing encoding after write is possible.

          This method does an implicit stream flush before setting the
          new parameters.

          Added in version 3.7.

          Changed in version 3.11: The method supports
          ‘encoding="locale"’ option.

      -- Method: seek (cookie, whence=os.SEEK_SET, /)

          Set the stream position.  Return the new stream position as an
          *note int: 257.

          Four operations are supported, given by the following argument
          combinations:

             * ‘seek(0, SEEK_SET)’: Rewind to the start of the stream.

             * ‘seek(cookie, SEEK_SET)’: Restore a previous position;
               'cookie' 'must be' a number returned by *note tell():
               15f9.

             * ‘seek(0, SEEK_END)’: Fast-forward to the end of the
               stream.

             * ‘seek(0, SEEK_CUR)’: Leave the current stream position
               unchanged.

          Any other argument combinations are invalid, and may raise
          exceptions.

          See also
          ........

          *note os.SEEK_SET: 12d4, *note os.SEEK_CUR: 12d5, and *note
          os.SEEK_END: 12d6.

      -- Method: tell ()

          Return the stream position as an opaque number.  The return
          value of ‘tell()’ can be given as input to *note seek(): 2e25,
          to restore a previous stream position.

 -- Class: io.StringIO (initial_value='', newline='\n')

     A text stream using an in-memory text buffer.  It inherits from
     *note TextIOBase: 698.

     The text buffer is discarded when the *note close(): 1f6. method is
     called.

     The initial value of the buffer can be set by providing
     'initial_value'.  If newline translation is enabled, newlines will
     be encoded as if by *note write(): 1e13.  The stream is positioned
     at the start of the buffer which emulates opening an existing file
     in a ‘w+’ mode, making it ready for an immediate write from the
     beginning or for a write that would overwrite the initial value.
     To emulate opening a file in an ‘a+’ mode ready for appending, use
     ‘f.seek(0, io.SEEK_END)’ to reposition the stream at the end of the
     buffer.

     The 'newline' argument works like that of *note TextIOWrapper: 7bf,
     except that when writing output to the stream, if 'newline' is
     ‘None’, newlines are written as ‘\n’ on all platforms.

     ‘StringIO’ provides this method in addition to those from *note
     TextIOBase: 698. and *note IOBase: 1f5.:

      -- Method: getvalue ()

          Return a *note str: 44f. containing the entire contents of the
          buffer.  Newlines are decoded as if by *note read(): 1e24,
          although the stream position is not changed.

     Example usage:

          import io

          output = io.StringIO()
          output.write('First line.\n')
          print('Second line.', file=output)

          # Retrieve file contents -- this will be
          # 'First line.\nSecond line.\n'
          contents = output.getvalue()

          # Close object and discard memory buffer --
          # .getvalue() will now raise an exception.
          output.close()

 -- Class: io.IncrementalNewlineDecoder

     A helper codec that decodes newlines for *note universal newlines:
     d62. mode.  It inherits from *note codecs.IncrementalDecoder: 2583.


File: python.info,  Node: Performance<3>,  Prev: Class hierarchy,  Up: io — Core tools for working with streams

5.16.2.13 Performance
.....................

This section discusses the performance of the provided concrete I/O
implementations.

* Menu:

* Binary I/O: Binary I/O<2>.
* Text I/O: Text I/O<3>.
* Multi-threading: Multi-threading<3>.
* Reentrancy::


File: python.info,  Node: Binary I/O<2>,  Next: Text I/O<3>,  Up: Performance<3>

5.16.2.14 Binary I/O
....................

By reading and writing only large chunks of data even when the user asks
for a single byte, buffered I/O hides any inefficiency in calling and
executing the operating system’s unbuffered I/O routines.  The gain
depends on the OS and the kind of I/O which is performed.  For example,
on some modern OSes such as Linux, unbuffered disk I/O can be as fast as
buffered I/O. The bottom line, however, is that buffered I/O offers
predictable performance regardless of the platform and the backing
device.  Therefore, it is almost always preferable to use buffered I/O
rather than unbuffered I/O for binary data.


File: python.info,  Node: Text I/O<3>,  Next: Multi-threading<3>,  Prev: Binary I/O<2>,  Up: Performance<3>

5.16.2.15 Text I/O
..................

Text I/O over a binary storage (such as a file) is significantly slower
than binary I/O over the same storage, because it requires conversions
between unicode and binary data using a character codec.  This can
become noticeable handling huge amounts of text data like large log
files.  Also, *note tell(): 2e22. and *note seek(): 2e21. are both quite
slow due to the reconstruction algorithm used.

*note StringIO: f5e, however, is a native in-memory unicode container
and will exhibit similar speed to *note BytesIO: ed8.


File: python.info,  Node: Multi-threading<3>,  Next: Reentrancy,  Prev: Text I/O<3>,  Up: Performance<3>

5.16.2.16 Multi-threading
.........................

*note FileIO: 1359. objects are thread-safe to the extent that the
operating system calls (such as ‘read(2)(1)’ under Unix) they wrap are
thread-safe too.

Binary buffered objects (instances of *note BufferedReader: 1253, *note
BufferedWriter: 13fe, *note BufferedRandom: 13ff. and *note
BufferedRWPair: 1400.) protect their internal structures using a lock;
it is therefore safe to call them from multiple threads at once.

*note TextIOWrapper: 7bf. objects are not thread-safe.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/read(2)


File: python.info,  Node: Reentrancy,  Prev: Multi-threading<3>,  Up: Performance<3>

5.16.2.17 Reentrancy
....................

Binary buffered objects (instances of *note BufferedReader: 1253, *note
BufferedWriter: 13fe, *note BufferedRandom: 13ff. and *note
BufferedRWPair: 1400.) are not reentrant.  While reentrant calls will
not happen in normal situations, they can arise from doing I/O in a
*note signal: c6. handler.  If a thread tries to re-enter a buffered
object which it is already accessing, a *note RuntimeError: 195. is
raised.  Note this doesn’t prohibit a different thread from entering the
buffered object.

The above implicitly extends to text files, since the *note open(): 51f.
function will wrap a buffered object inside a *note TextIOWrapper: 7bf.
This includes standard streams and therefore affects the built-in *note
print(): fae. function as well.


File: python.info,  Node: time — Time access and conversions,  Next: logging — Logging facility for Python,  Prev: io — Core tools for working with streams,  Up: Generic Operating System Services

5.16.3 ‘time’ — Time access and conversions
-------------------------------------------

__________________________________________________________________

This module provides various time-related functions.  For related
functionality, see also the *note datetime: 30. and *note calendar: 14.
modules.

Although this module is always available, not all functions are
available on all platforms.  Most of the functions defined in this
module call platform C library functions with the same name.  It may
sometimes be helpful to consult the platform documentation, because the
semantics of these functions varies among platforms.

An explanation of some terminology and conventions is in order.

   * The 'epoch' is the point where the time starts, the return value of
     ‘time.gmtime(0)’.  It is January 1, 1970, 00:00:00 (UTC) on all
     platforms.

   * The term 'seconds since the epoch' refers to the total number of
     elapsed seconds since the epoch, typically excluding leap
     seconds(1).  Leap seconds are excluded from this total on all
     POSIX-compliant platforms.

   * The functions in this module may not handle dates and times before
     the *note epoch: 2c12. or far in the future.  The cut-off point in
     the future is determined by the C library; for 32-bit systems, it
     is typically in 2038.

   * Function *note strptime(): 147b. can parse 2-digit years when given
     ‘%y’ format code.  When 2-digit years are parsed, they are
     converted according to the POSIX and ISO C standards: values 69–99
     are mapped to 1969–1999, and values 0–68 are mapped to 2000–2068.

   * UTC is Coordinated Universal Time(2) and superseded Greenwich Mean
     Time(3) or GMT as the basis of international timekeeping.  The
     acronym UTC is not a mistake but conforms to an earlier,
     language-agnostic naming scheme for time standards such as UT0,
     UT1, and UT2.

   * DST is Daylight Saving Time, an adjustment of the timezone by
     (usually) one hour during part of the year.  DST rules are magic
     (determined by local law) and can change from year to year.  The C
     library has a table containing the local rules (often it is read
     from a system file for flexibility) and is the only source of True
     Wisdom in this respect.

   * The precision of the various real-time functions may be less than
     suggested by the units in which their value or argument is
     expressed.  E.g.  on most Unix systems, the clock “ticks” only 50
     or 100 times a second.

   * On the other hand, the precision of *note time(): 254. and *note
     sleep(): 6a0. is better than their Unix equivalents: times are
     expressed as floating-point numbers, ‘time()’ returns the most
     accurate time available (using Unix ‘gettimeofday()’ where
     available), and ‘sleep()’ will accept a time with a nonzero
     fraction (Unix ‘select()’ is used to implement this, where
     available).

   * The time value as returned by *note gmtime(): 1205, *note
     localtime(): 1548, and *note strptime(): 147b, and accepted by
     *note asctime(): 122c, *note mktime(): 122d. and *note strftime():
     122e, is a sequence of 9 integers.  The return values of
     ‘gmtime()’, ‘localtime()’, and ‘strptime()’ also offer attribute
     names for individual fields.

     See *note struct_time: d11. for a description of these objects.

     Changed in version 3.3: The *note struct_time: d11. type was
     extended to provide the *note tm_gmtoff: 2e2f. and *note tm_zone:
     2e30. attributes when platform supports corresponding ‘struct tm’
     members.

     Changed in version 3.6: The *note struct_time: d11. attributes
     *note tm_gmtoff: 2e2f. and *note tm_zone: 2e30. are now available
     on all platforms.

   * Use the following functions to convert between time
     representations:

     From                          To                            Use
                                                                 
     ------------------------------------------------------------------------------------------
                                                                 
     seconds since the epoch       *note struct_time: d11. in    *note gmtime(): 1205.
                                   UTC                           
                                   
                                                                 
     seconds since the epoch       *note struct_time: d11. in    *note localtime(): 1548.
                                   local time                    
                                   
                                                                 
     *note struct_time: d11. in    seconds since the epoch       *note calendar.timegm(): 2695.
     UTC                                                         

     *note struct_time: d11. in    seconds since the epoch       *note mktime(): 122d.
     local time                                                  

* Menu:

* Functions: Functions<5>.
* Clock ID Constants::
* Timezone Constants::

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Leap_second

   (2) https://en.wikipedia.org/wiki/Coordinated_Universal_Time

   (3) https://en.wikipedia.org/wiki/Greenwich_Mean_Time


File: python.info,  Node: Functions<5>,  Next: Clock ID Constants,  Up: time — Time access and conversions

5.16.3.1 Functions
..................

 -- Function: time.asctime ([t])

     Convert a tuple or *note struct_time: d11. representing a time as
     returned by *note gmtime(): 1205. or *note localtime(): 1548. to a
     string of the following form: ‘'Sun Jun 20 23:21:05 1993'’.  The
     day field is two characters long and is space padded if the day is
     a single digit, e.g.: ‘'Wed Jun 9 04:26:40 1993'’.

     If 't' is not provided, the current time as returned by *note
     localtime(): 1548. is used.  Locale information is not used by
     ‘asctime()’.

          Note: Unlike the C function of the same name, ‘asctime()’ does
          not add a trailing newline.

 -- Function: time.pthread_getcpuclockid (thread_id)

     Return the 'clk_id' of the thread-specific CPU-time clock for the
     specified 'thread_id'.

     Use *note threading.get_ident(): 119e. or the *note ident: 2e33.
     attribute of *note threading.Thread: 956. objects to get a suitable
     value for 'thread_id'.

          Warning: Passing an invalid or expired 'thread_id' may result
          in undefined behavior, such as segmentation fault.

     *note Availability: 1ef7.: Unix

     See the man page for ‘pthread_getcpuclockid(3)(1)’ for further
     information.

     Added in version 3.7.

 -- Function: time.clock_getres (clk_id)

     Return the resolution (precision) of the specified clock 'clk_id'.
     Refer to *note Clock ID Constants: 2dab. for a list of accepted
     values for 'clk_id'.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: time.clock_gettime (clk_id) -> float

     Return the time of the specified clock 'clk_id'.  Refer to *note
     Clock ID Constants: 2dab. for a list of accepted values for
     'clk_id'.

     Use *note clock_gettime_ns(): afa. to avoid the precision loss
     caused by the *note float: 2f7. type.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Function: time.clock_gettime_ns (clk_id) -> int

     Similar to *note clock_gettime(): 11a2. but return time as
     nanoseconds.

     *note Availability: 1ef7.: Unix.

     Added in version 3.7.

 -- Function: time.clock_settime (clk_id, time: float)

     Set the time of the specified clock 'clk_id'.  Currently, *note
     CLOCK_REALTIME: 69d. is the only accepted value for 'clk_id'.

     Use *note clock_settime_ns(): afb. to avoid the precision loss
     caused by the *note float: 2f7. type.

     *note Availability: 1ef7.: Unix, not Android, not iOS.

     Added in version 3.3.

 -- Function: time.clock_settime_ns (clk_id, time: int)

     Similar to *note clock_settime(): 11a3. but set time with
     nanoseconds.

     *note Availability: 1ef7.: Unix, not Android, not iOS.

     Added in version 3.7.

 -- Function: time.ctime ([secs])

     Convert a time expressed in seconds since the *note epoch: 2c12. to
     a string of a form: ‘'Sun Jun 20 23:21:05 1993'’ representing local
     time.  The day field is two characters long and is space padded if
     the day is a single digit, e.g.: ‘'Wed Jun 9 04:26:40 1993'’.

     If 'secs' is not provided or *note None: 678, the current time as
     returned by *note time(): 254. is used.  ‘ctime(secs)’ is
     equivalent to ‘asctime(localtime(secs))’.  Locale information is
     not used by ‘ctime()’.

 -- Function: time.get_clock_info (name)

     Get information on the specified clock as a namespace object.
     Supported clock names and the corresponding functions to read their
     value are:

        * ‘'monotonic'’: *note time.monotonic(): 253.

        * ‘'perf_counter'’: *note time.perf_counter(): a97.

        * ‘'process_time'’: *note time.process_time(): a98.

        * ‘'thread_time'’: *note time.thread_time(): 940.

        * ‘'time'’: *note time.time(): 254.

     The result has the following attributes:

        - 'adjustable': ‘True’ if the clock can be set to jump forward
          or backward in time, ‘False’ otherwise.  Does not refer to
          gradual NTP rate adjustments.

        - 'implementation': The name of the underlying C function used
          to get the clock value.  Refer to *note Clock ID Constants:
          2dab. for possible values.

        - 'monotonic': ‘True’ if the clock cannot go backward, ‘False’
          otherwise

        - 'resolution': The resolution of the clock in seconds (*note
          float: 2f7.)

     Added in version 3.3.

 -- Function: time.gmtime ([secs])

     Convert a time expressed in seconds since the *note epoch: 2c12. to
     a *note struct_time: d11. in UTC in which the dst flag is always
     zero.  If 'secs' is not provided or *note None: 678, the current
     time as returned by *note time(): 254. is used.  Fractions of a
     second are ignored.  See above for a description of the
     ‘struct_time’ object.  See *note calendar.timegm(): 2695. for the
     inverse of this function.

 -- Function: time.localtime ([secs])

     Like *note gmtime(): 1205. but converts to local time.  If 'secs'
     is not provided or *note None: 678, the current time as returned by
     *note time(): 254. is used.  The dst flag is set to ‘1’ when DST
     applies to the given time.

     ‘localtime()’ may raise *note OverflowError: 888, if the timestamp
     is outside the range of values supported by the platform C
     ‘localtime()’ or ‘gmtime()’ functions, and *note OSError: 41a. on
     ‘localtime()’ or ‘gmtime()’ failure.  It’s common for this to be
     restricted to years between 1970 and 2038.

 -- Function: time.mktime (t)

     This is the inverse function of *note localtime(): 1548.  Its
     argument is the *note struct_time: d11. or full 9-tuple (since the
     dst flag is needed; use ‘-1’ as the dst flag if it is unknown)
     which expresses the time in 'local' time, not UTC. It returns a
     floating-point number, for compatibility with *note time(): 254.
     If the input value cannot be represented as a valid time, either
     *note OverflowError: 888. or *note ValueError: 202. will be raised
     (which depends on whether the invalid value is caught by Python or
     the underlying C libraries).  The earliest date for which it can
     generate a time is platform-dependent.

 -- Function: time.monotonic () -> float

     Return the value (in fractional seconds) of a monotonic clock, i.e.
     a clock that cannot go backwards.  The clock is not affected by
     system clock updates.  The reference point of the returned value is
     undefined, so that only the difference between the results of two
     calls is valid.

     Clock:

        * On Windows, call ‘QueryPerformanceCounter()’ and
          ‘QueryPerformanceFrequency()’.

        * On macOS, call ‘mach_absolute_time()’ and
          ‘mach_timebase_info()’.

        * On HP-UX, call ‘gethrtime()’.

        * Call ‘clock_gettime(CLOCK_HIGHRES)’ if available.

        * Otherwise, call ‘clock_gettime(CLOCK_MONOTONIC)’.

     Use *note monotonic_ns(): afc. to avoid the precision loss caused
     by the *note float: 2f7. type.

     Added in version 3.3.

     Changed in version 3.5: The function is now always available and
     the clock is now the same for all processes.

     Changed in version 3.10: On macOS, the clock is now the same for
     all processes.

 -- Function: time.monotonic_ns () -> int

     Similar to *note monotonic(): 253, but return time as nanoseconds.

     Added in version 3.7.

 -- Function: time.perf_counter () -> float

     Return the value (in fractional seconds) of a performance counter,
     i.e.  a clock with the highest available resolution to measure a
     short duration.  It does include time elapsed during sleep.  The
     clock is the same for all processes.  The reference point of the
     returned value is undefined, so that only the difference between
     the results of two calls is valid.

     'CPython implementation detail:' On CPython, use the same clock as
     *note time.monotonic(): 253. and is a monotonic clock, i.e.  a
     clock that cannot go backwards.

     Use *note perf_counter_ns(): afd. to avoid the precision loss
     caused by the *note float: 2f7. type.

     Added in version 3.3.

     Changed in version 3.10: On Windows, the clock is now the same for
     all processes.

     Changed in version 3.13: Use the same clock as *note
     time.monotonic(): 253.

 -- Function: time.perf_counter_ns () -> int

     Similar to *note perf_counter(): a97, but return time as
     nanoseconds.

     Added in version 3.7.

 -- Function: time.process_time () -> float

     Return the value (in fractional seconds) of the sum of the system
     and user CPU time of the current process.  It does not include time
     elapsed during sleep.  It is process-wide by definition.  The
     reference point of the returned value is undefined, so that only
     the difference between the results of two calls is valid.

     Use *note process_time_ns(): afe. to avoid the precision loss
     caused by the *note float: 2f7. type.

     Added in version 3.3.

 -- Function: time.process_time_ns () -> int

     Similar to *note process_time(): a98. but return time as
     nanoseconds.

     Added in version 3.7.

 -- Function: time.sleep (secs)

     Suspend execution of the calling thread for the given number of
     seconds.  The argument may be a floating-point number to indicate a
     more precise sleep time.

     If the sleep is interrupted by a signal and no exception is raised
     by the signal handler, the sleep is restarted with a recomputed
     timeout.

     The suspension time may be longer than requested by an arbitrary
     amount, because of the scheduling of other activity in the system.

     Windows implementation
     ......................

     On Windows, if 'secs' is zero, the thread relinquishes the
     remainder of its time slice to any other thread that is ready to
     run.  If there are no other threads ready to run, the function
     returns immediately, and the thread continues execution.  On
     Windows 10 and newer the implementation uses a high-resolution
     timer(2) which provides resolution of 100 nanoseconds.  If 'secs'
     is zero, ‘Sleep(0)’ is used.

     Unix implementation
     ...................

        * Use ‘clock_nanosleep()’ if available (resolution: 1
          nanosecond);

        * Or use ‘nanosleep()’ if available (resolution: 1 nanosecond);

        * Or use ‘select()’ (resolution: 1 microsecond).

          Note: To emulate a “no-op”, use *note pass: 1db1. instead of
          ‘time.sleep(0)’.

          To voluntarily relinquish the CPU, specify a real-time *note
          scheduling policy: 2df3. and use *note os.sched_yield(): 1155.
          instead.

     Raises an *note auditing event: 1a15. ‘time.sleep’ with argument
     ‘secs’.

     Changed in version 3.5: The function now sleeps at least 'secs'
     even if the sleep is interrupted by a signal, except if the signal
     handler raises an exception (see PEP 475(3) for the rationale).

     Changed in version 3.11: On Unix, the ‘clock_nanosleep()’ and
     ‘nanosleep()’ functions are now used if available.  On Windows, a
     waitable timer is now used.

     Changed in version 3.13: Raises an auditing event.

 -- Function: time.strftime (format[, t])

     Convert a tuple or *note struct_time: d11. representing a time as
     returned by *note gmtime(): 1205. or *note localtime(): 1548. to a
     string as specified by the 'format' argument.  If 't' is not
     provided, the current time as returned by ‘localtime()’ is used.
     'format' must be a string.  *note ValueError: 202. is raised if any
     field in 't' is outside of the allowed range.

     0 is a legal argument for any position in the time tuple; if it is
     normally illegal the value is forced to a correct one.

     The following directives can be embedded in the 'format' string.
     They are shown without the optional field width and precision
     specification, and are replaced by the indicated characters in the
     ‘strftime()’ result:

     Directive       Meaning                                              Notes
                                                                          
     ---------------------------------------------------------------------------------
                                                                          
     ‘%a’            Locale’s abbreviated weekday name.
                     
                                                                          
     ‘%A’            Locale’s full weekday name.
                     
                                                                          
     ‘%b’            Locale’s abbreviated month name.
                     
                                                                          
     ‘%B’            Locale’s full month name.
                     
                                                                          
     ‘%c’            Locale’s appropriate date and time representation.
                     
                                                                          
     ‘%d’            Day of the month as a decimal number [01,31].
                     
                                                                          
     ‘%f’            Microseconds as a decimal number                     (1)
                                                                          
                          [000000,999999].
                     
                                                                          
     ‘%H’            Hour (24-hour clock) as a decimal number [00,23].
                     
                                                                          
     ‘%I’            Hour (12-hour clock) as a decimal number [01,12].
                     
                                                                          
     ‘%j’            Day of the year as a decimal number [001,366].
                     
                                                                          
     ‘%m’            Month as a decimal number [01,12].
                     
                                                                          
     ‘%M’            Minute as a decimal number [00,59].
                     
                                                                          
     ‘%p’            Locale’s equivalent of either AM or PM.              (2)
                                                                          
                                                                          
     ‘%S’            Second as a decimal number [00,61].                  (3)
                                                                          
                                                                          
     ‘%U’            Week number of the year (Sunday as the first day     (4)
                     of the week) as a decimal number [00,53].  All       
                     days in a new year preceding the first Sunday are
                     considered to be in week 0.
                     
                                                                          
     ‘%u’            Day of the week (Monday is 1; Sunday is 7) as a
                     decimal number [1, 7].
                     
                                                                          
     ‘%w’            Weekday as a decimal number [0(Sunday),6].
                     
                                                                          
     ‘%W’            Week number of the year (Monday as the first day     (4)
                     of the week) as a decimal number [00,53].  All       
                     days in a new year preceding the first Monday are
                     considered to be in week 0.
                     
                                                                          
     ‘%x’            Locale’s appropriate date representation.
                     
                                                                          
     ‘%X’            Locale’s appropriate time representation.
                     
                                                                          
     ‘%y’            Year without century as a decimal number [00,99].
                     
                                                                          
     ‘%Y’            Year with century as a decimal number.
                     
                                                                          
     ‘%z’            Time zone offset indicating a positive or negative
                     time difference from UTC/GMT of the form +HHMM or
                     -HHMM, where H represents decimal hour digits and
                     M represents decimal minute digits [-23:59,
                     +23:59].  (4)
                     
                                                                          
     ‘%Z’            Time zone name (no characters if no time zone
                     exists).  Deprecated.  (5)
                     
                                                                          
     ‘%G’            ISO 8601 year (similar to ‘%Y’ but follows the
                     rules for the ISO 8601 calendar year).  The year
                     starts with the week that contains the first
                     Thursday of the calendar year.
                     
                                                                          
     ‘%V’            ISO 8601 week number (as a decimal number
                     [01,53]).  The first week of the year is the one
                     that contains the first Thursday of the year.
                     Weeks start on Monday.
                     
                                                                          
     ‘%%’            A literal ‘'%'’ character.
                     

     Notes:

       1. The ‘%f’ format directive only applies to *note strptime():
          147b, not to ‘strftime()’.  However, see also *note
          datetime.datetime.strptime(): 1714. and *note
          datetime.datetime.strftime(): cb5. where the ‘%f’ format
          directive *note applies to microseconds: 25e4.

       2. When used with the *note strptime(): 147b. function, the ‘%p’
          directive only affects the output hour field if the ‘%I’
          directive is used to parse the hour.

       3. The range really is ‘0’ to ‘61’; value ‘60’ is valid in
          timestamps representing leap seconds(6) and value ‘61’ is
          supported for historical reasons.

       4. When used with the *note strptime(): 147b. function, ‘%U’ and
          ‘%W’ are only used in calculations when the day of the week
          and the year are specified.

     Here is an example, a format for dates compatible with that
     specified in the RFC 5322(7) Internet email standard.  (8)

          >>> from time import gmtime, strftime
          >>> strftime("%a, %d %b %Y %H:%M:%S +0000", gmtime())
          'Thu, 28 Jun 2001 14:17:15 +0000'

     Additional directives may be supported on certain platforms, but
     only the ones listed here have a meaning standardized by ANSI C. To
     see the full set of format codes supported on your platform,
     consult the ‘strftime(3)(9)’ documentation.

     On some platforms, an optional field width and precision
     specification can immediately follow the initial ‘'%'’ of a
     directive in the following order; this is also not portable.  The
     field width is normally 2 except for ‘%j’ where it is 3.

 -- Function: time.strptime (string[, format])

     Parse a string representing a time according to a format.  The
     return value is a *note struct_time: d11. as returned by *note
     gmtime(): 1205. or *note localtime(): 1548.

     The 'format' parameter uses the same directives as those used by
     *note strftime(): 122e.; it defaults to ‘"%a %b %d %H:%M:%S %Y"’
     which matches the formatting returned by *note ctime(): 2612.  If
     'string' cannot be parsed according to 'format', or if it has
     excess data after parsing, *note ValueError: 202. is raised.  The
     default values used to fill in any missing data when more accurate
     values cannot be inferred are ‘(1900, 1, 1, 0, 0, 0, 0, 1, -1)’.
     Both 'string' and 'format' must be strings.

     For example:

          >>> import time
          >>> time.strptime("30 Nov 00", "%d %b %y")
          time.struct_time(tm_year=2000, tm_mon=11, tm_mday=30, tm_hour=0, tm_min=0,
                           tm_sec=0, tm_wday=3, tm_yday=335, tm_isdst=-1)

     Support for the ‘%Z’ directive is based on the values contained in
     ‘tzname’ and whether ‘daylight’ is true.  Because of this, it is
     platform-specific except for recognizing UTC and GMT which are
     always known (and are considered to be non-daylight savings
     timezones).

     Only the directives specified in the documentation are supported.
     Because ‘strftime()’ is implemented per platform it can sometimes
     offer more directives than those listed.  But ‘strptime()’ is
     independent of any platform and thus does not necessarily support
     all directives available that are not documented as supported.

 -- Class: time.struct_time

     The type of the time value sequence returned by *note gmtime():
     1205, *note localtime(): 1548, and *note strptime(): 147b.  It is
     an object with a *note named tuple: 651. interface: values can be
     accessed by index and by attribute name.  The following values are
     present:

     Index                                 Attribute                             Values
                                                                                 
                                                                                 
     0                                      -- Attribute: tm_year                (for example, 1993)
                                                                                 
                                                                                 
     1                                      -- Attribute: tm_mon                 range [1, 12]
                                                                                 
                                                                                 
     2                                      -- Attribute: tm_mday                range [1, 31]
                                                                                 
                                                                                 
     3                                      -- Attribute: tm_hour                range [0, 23]
                                                                                 
                                                                                 
     4                                      -- Attribute: tm_min                 range [0, 59]
                                                                                 
                                                                                 
     5                                      -- Attribute: tm_sec                 range [0, 61]; see
                                                                                 *note Note (2): 2e34. in
                                                                                 *note strftime(): 122e.
                                                                                 
                                                                                 
     6                                      -- Attribute: tm_wday                range [0, 6]; Monday is 0
                                                                                 
                                                                                 
     7                                      -- Attribute: tm_yday                range [1, 366]
                                                                                 
                                                                                 
     8                                      -- Attribute: tm_isdst               0, 1 or -1; see below
                                                                                 
                                                                                 
     N/A                                    -- Attribute: tm_zone                abbreviation of timezone name
                                                                                 
                                                                                 
     N/A                                    -- Attribute: tm_gmtoff              offset east of UTC in seconds
                                                                                 

     Note that unlike the C structure, the month value is a range of [1,
     12], not [0, 11].

     In calls to *note mktime(): 122d, *note tm_isdst: 2623. may be set
     to 1 when daylight savings time is in effect, and 0 when it is not.
     A value of -1 indicates that this is not known, and will usually
     result in the correct state being filled in.

     When a tuple with an incorrect length is passed to a function
     expecting a ‘struct_time’, or having elements of the wrong type, a
     *note TypeError: 2c3. is raised.

 -- Function: time.time () -> float

     Return the time in seconds since the *note epoch: 2c12. as a
     floating-point number.  The handling of leap seconds(10) is
     platform dependent.  On Windows and most Unix systems, the leap
     seconds are not counted towards the time in seconds since the *note
     epoch: 2c12.  This is commonly referred to as Unix time(11).

     Note that even though the time is always returned as a
     floating-point number, not all systems provide time with a better
     precision than 1 second.  While this function normally returns
     non-decreasing values, it can return a lower value than a previous
     call if the system clock has been set back between the two calls.

     The number returned by ‘time()’ may be converted into a more common
     time format (i.e.  year, month, day, hour, etc…) in UTC by passing
     it to *note gmtime(): 1205. function or in local time by passing it
     to the *note localtime(): 1548. function.  In both cases a *note
     struct_time: d11. object is returned, from which the components of
     the calendar date may be accessed as attributes.

     Clock:

        * On Windows, call ‘GetSystemTimePreciseAsFileTime()’.

        * Call ‘clock_gettime(CLOCK_REALTIME)’ if available.

        * Otherwise, call ‘gettimeofday()’.

     Use *note time_ns(): aff. to avoid the precision loss caused by the
     *note float: 2f7. type.

Changed in version 3.13: On Windows, calls
‘GetSystemTimePreciseAsFileTime()’ instead of
‘GetSystemTimeAsFileTime()’.

 -- Function: time.time_ns () -> int

     Similar to *note time(): 254. but returns time as an integer number
     of nanoseconds since the *note epoch: 2c12.

     Added in version 3.7.

 -- Function: time.thread_time () -> float

     Return the value (in fractional seconds) of the sum of the system
     and user CPU time of the current thread.  It does not include time
     elapsed during sleep.  It is thread-specific by definition.  The
     reference point of the returned value is undefined, so that only
     the difference between the results of two calls in the same thread
     is valid.

     Use *note thread_time_ns(): baf. to avoid the precision loss caused
     by the *note float: 2f7. type.

     *note Availability: 1ef7.: Linux, Unix, Windows.

     Unix systems supporting ‘CLOCK_THREAD_CPUTIME_ID’.

     Added in version 3.7.

 -- Function: time.thread_time_ns () -> int

     Similar to *note thread_time(): 940. but return time as
     nanoseconds.

     Added in version 3.7.

 -- Function: time.tzset ()

     Reset the time conversion rules used by the library routines.  The
     environment variable ‘TZ’ specifies how this is done.  It will also
     set the variables ‘tzname’ (from the ‘TZ’ environment variable),
     ‘timezone’ (non-DST seconds West of UTC), ‘altzone’ (DST seconds
     west of UTC) and ‘daylight’ (to 0 if this timezone does not have
     any daylight saving time rules, or to nonzero if there is a time,
     past, present or future when daylight saving time applies).

     *note Availability: 1ef7.: Unix.

          Note: Although in many cases, changing the ‘TZ’ environment
          variable may affect the output of functions like *note
          localtime(): 1548. without calling ‘tzset()’, this behavior
          should not be relied on.

          The ‘TZ’ environment variable should contain no whitespace.

     The standard format of the ‘TZ’ environment variable is (whitespace
     added for clarity):

          std offset [dst [offset [,start[/time], end[/time]]]]

     Where the components are:

     ‘std’ and ‘dst’

          Three or more alphanumerics giving the timezone abbreviations.
          These will be propagated into time.tzname

     ‘offset’

          The offset has the form: ‘± hh[:mm[:ss]]’.  This indicates the
          value added the local time to arrive at UTC. If preceded by a
          ‘-’, the timezone is east of the Prime Meridian; otherwise, it
          is west.  If no offset follows dst, summer time is assumed to
          be one hour ahead of standard time.

     ‘start[/time], end[/time]’

          Indicates when to change to and back from DST. The format of
          the start and end dates are one of the following:

          ‘JN’

               The Julian day 'n' (1 <= 'n' <= 365).  Leap days are not
               counted, so in all years February 28 is day 59 and March
               1 is day 60.

          ‘N’

               The zero-based Julian day (0 <= 'n' <= 365).  Leap days
               are counted, and it is possible to refer to February 29.

          ‘MM.N.D’

               The 'd'’th day (0 <= 'd' <= 6) of week 'n' of month 'm'
               of the year (1 <= 'n' <= 5, 1 <= 'm' <= 12, where week 5
               means “the last 'd' day in month 'm'” which may occur in
               either the fourth or the fifth week).  Week 1 is the
               first week in which the 'd'’th day occurs.  Day zero is a
               Sunday.

          ‘time’ has the same format as ‘offset’ except that no leading
          sign (‘-’ or ‘+’) is allowed.  The default, if time is not
          given, is 02:00:00.

          >>> os.environ['TZ'] = 'EST+05EDT,M4.1.0,M10.5.0'
          >>> time.tzset()
          >>> time.strftime('%X %x %Z')
          '02:07:36 05/08/03 EDT'
          >>> os.environ['TZ'] = 'AEST-10AEDT-11,M10.5.0,M3.5.0'
          >>> time.tzset()
          >>> time.strftime('%X %x %Z')
          '16:08:12 05/08/03 AEST'

     On many Unix systems (including *BSD, Linux, Solaris, and Darwin),
     it is more convenient to use the system’s zoneinfo
     (‘tzfile(5)(12)’) database to specify the timezone rules.  To do
     this, set the ‘TZ’ environment variable to the path of the required
     timezone datafile, relative to the root of the systems ‘zoneinfo’
     timezone database, usually located at ‘/usr/share/zoneinfo’.  For
     example, ‘'US/Eastern'’, ‘'Australia/Melbourne'’, ‘'Egypt'’ or
     ‘'Europe/Amsterdam'’.

          >>> os.environ['TZ'] = 'US/Eastern'
          >>> time.tzset()
          >>> time.tzname
          ('EST', 'EDT')
          >>> os.environ['TZ'] = 'Egypt'
          >>> time.tzset()
          >>> time.tzname
          ('EET', 'EEST')

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/pthread_getcpuclockid(3)

   (2) 
https://learn.microsoft.com/windows/win32/api/synchapi/nf-synchapi-createwaitabletimerexw

   (3) https://peps.python.org/pep-0475/

   (4) The use of ‘%Z’ is now deprecated, but the ‘%z’ escape that
expands to the preferred hour/minute offset is not supported by all ANSI
C libraries.  Also, a strict reading of the original 1982 RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) standard calls for a
two-digit year (‘%y’ rather than ‘%Y’), but practice moved to 4-digit
years long before the year 2000.  After that, RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) became obsolete and
the 4-digit year has been first recommended by RFC 1123
(https://datatracker.ietf.org/doc/html/rfc1123.html) and then mandated
by RFC 2822 (https://datatracker.ietf.org/doc/html/rfc2822.html), with
RFC 5322 (https://datatracker.ietf.org/doc/html/rfc5322.html) continuing
this requirement.

   (5) The use of ‘%Z’ is now deprecated, but the ‘%z’ escape that
expands to the preferred hour/minute offset is not supported by all ANSI
C libraries.  Also, a strict reading of the original 1982 RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) standard calls for a
two-digit year (‘%y’ rather than ‘%Y’), but practice moved to 4-digit
years long before the year 2000.  After that, RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) became obsolete and
the 4-digit year has been first recommended by RFC 1123
(https://datatracker.ietf.org/doc/html/rfc1123.html) and then mandated
by RFC 2822 (https://datatracker.ietf.org/doc/html/rfc2822.html), with
RFC 5322 (https://datatracker.ietf.org/doc/html/rfc5322.html) continuing
this requirement.

   (6) https://en.wikipedia.org/wiki/Leap_second

   (7) https://datatracker.ietf.org/doc/html/rfc5322.html

   (8) The use of ‘%Z’ is now deprecated, but the ‘%z’ escape that
expands to the preferred hour/minute offset is not supported by all ANSI
C libraries.  Also, a strict reading of the original 1982 RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) standard calls for a
two-digit year (‘%y’ rather than ‘%Y’), but practice moved to 4-digit
years long before the year 2000.  After that, RFC 822
(https://datatracker.ietf.org/doc/html/rfc822.html) became obsolete and
the 4-digit year has been first recommended by RFC 1123
(https://datatracker.ietf.org/doc/html/rfc1123.html) and then mandated
by RFC 2822 (https://datatracker.ietf.org/doc/html/rfc2822.html), with
RFC 5322 (https://datatracker.ietf.org/doc/html/rfc5322.html) continuing
this requirement.

   (9) https://manpages.debian.org/strftime(3)

   (10) https://en.wikipedia.org/wiki/Leap_second

   (11) https://en.wikipedia.org/wiki/Unix_time

   (12) https://manpages.debian.org/tzfile(5)


File: python.info,  Node: Clock ID Constants,  Next: Timezone Constants,  Prev: Functions<5>,  Up: time — Time access and conversions

5.16.3.2 Clock ID Constants
...........................

These constants are used as parameters for *note clock_getres(): 11a1.
and *note clock_gettime(): 11a2.

 -- Data: time.CLOCK_BOOTTIME

     Identical to *note CLOCK_MONOTONIC: 69c, except it also includes
     any time that the system is suspended.

     This allows applications to get a suspend-aware monotonic clock
     without having to deal with the complications of *note
     CLOCK_REALTIME: 69d, which may have discontinuities if the time is
     changed using ‘settimeofday()’ or similar.

     *note Availability: 1ef7.: Linux >= 2.6.39.

     Added in version 3.7.

 -- Data: time.CLOCK_HIGHRES

     The Solaris OS has a ‘CLOCK_HIGHRES’ timer that attempts to use an
     optimal hardware source, and may give close to nanosecond
     resolution.  ‘CLOCK_HIGHRES’ is the nonadjustable, high-resolution
     clock.

     *note Availability: 1ef7.: Solaris.

     Added in version 3.3.

 -- Data: time.CLOCK_MONOTONIC

     Clock that cannot be set and represents monotonic time since some
     unspecified starting point.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Data: time.CLOCK_MONOTONIC_RAW

     Similar to *note CLOCK_MONOTONIC: 69c, but provides access to a raw
     hardware-based time that is not subject to NTP adjustments.

     *note Availability: 1ef7.: Linux >= 2.6.28, macOS >= 10.12.

     Added in version 3.3.

 -- Data: time.CLOCK_MONOTONIC_RAW_APPROX

     Similar to *note CLOCK_MONOTONIC_RAW: 2e3f, but reads a value
     cached by the system at context switch and hence has less accuracy.

     *note Availability: 1ef7.: macOS >= 10.12.

     Added in version 3.13.

 -- Data: time.CLOCK_PROCESS_CPUTIME_ID

     High-resolution per-process timer from the CPU.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Data: time.CLOCK_PROF

     High-resolution per-process timer from the CPU.

     *note Availability: 1ef7.: FreeBSD, NetBSD >= 7, OpenBSD.

     Added in version 3.7.

 -- Data: time.CLOCK_TAI

     International Atomic Time(1)

     The system must have a current leap second table in order for this
     to give the correct answer.  PTP or NTP software can maintain a
     leap second table.

     *note Availability: 1ef7.: Linux.

     Added in version 3.9.

 -- Data: time.CLOCK_THREAD_CPUTIME_ID

     Thread-specific CPU-time clock.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

 -- Data: time.CLOCK_UPTIME

     Time whose absolute value is the time the system has been running
     and not suspended, providing accurate uptime measurement, both
     absolute and interval.

     *note Availability: 1ef7.: FreeBSD, OpenBSD >= 5.5.

     Added in version 3.7.

 -- Data: time.CLOCK_UPTIME_RAW

     Clock that increments monotonically, tracking the time since an
     arbitrary point, unaffected by frequency or time adjustments and
     not incremented while the system is asleep.

     *note Availability: 1ef7.: macOS >= 10.12.

     Added in version 3.8.

 -- Data: time.CLOCK_UPTIME_RAW_APPROX

     Like *note CLOCK_UPTIME_RAW: a50, but the value is cached by the
     system at context switches and therefore has less accuracy.

     *note Availability: 1ef7.: macOS >= 10.12.

     Added in version 3.13.

The following constant is the only parameter that can be sent to *note
clock_settime(): 11a3.

 -- Data: time.CLOCK_REALTIME

     Real-time clock.  Setting this clock requires appropriate
     privileges.  The clock is the same for all processes.

     *note Availability: 1ef7.: Unix.

     Added in version 3.3.

   ---------- Footnotes ----------

   (1) 
https://www.nist.gov/pml/time-and-frequency-division/how-utcnist-related-coordinated-universal-time-utc-international


File: python.info,  Node: Timezone Constants,  Prev: Clock ID Constants,  Up: time — Time access and conversions

5.16.3.3 Timezone Constants
...........................

 -- Data: time.altzone

     The offset of the local DST timezone, in seconds west of UTC, if
     one is defined.  This is negative if the local DST timezone is east
     of UTC (as in Western Europe, including the UK). Only use this if
     ‘daylight’ is nonzero.  See note below.

 -- Data: time.daylight

     Nonzero if a DST timezone is defined.  See note below.

 -- Data: time.timezone

     The offset of the local (non-DST) timezone, in seconds west of UTC
     (negative in most of Western Europe, positive in the US, zero in
     the UK). See note below.

 -- Data: time.tzname

     A tuple of two strings: the first is the name of the local non-DST
     timezone, the second is the name of the local DST timezone.  If no
     DST timezone is defined, the second string should not be used.  See
     note below.

     Note: For the above Timezone constants (*note altzone: 2e46, *note
     daylight: 2e47, *note timezone: 2e48, and *note tzname: 2e49.), the
     value is determined by the timezone rules in effect at module load
     time or the last time *note tzset(): 2e3c. is called and may be
     incorrect for times in the past.  It is recommended to use the
     *note tm_gmtoff: 2e2f. and *note tm_zone: 2e30. results from *note
     localtime(): 1548. to obtain timezone information.

See also
........

Module *note datetime: 30.

     More object-oriented interface to dates and times.

Module *note locale: 86.

     Internationalization services.  The locale setting affects the
     interpretation of many format specifiers in *note strftime(): 122e.
     and *note strptime(): 147b.

Module *note calendar: 14.

     General calendar-related functions.  *note timegm(): 2695. is the
     inverse of *note gmtime(): 1205. from this module.


File: python.info,  Node: logging — Logging facility for Python,  Next: logging config — Logging configuration,  Prev: time — Time access and conversions,  Up: Generic Operating System Services

5.16.4 ‘logging’ — Logging facility for Python
----------------------------------------------

'Source code:' Lib/logging/__init__.py(1)

Important
.........

This page contains the API reference information.  For tutorial
information and discussion of more advanced topics, see

   * *note Basic Tutorial: 123a.

   * *note Advanced Tutorial: 123b.

   * *note Logging Cookbook: 123c.

__________________________________________________________________

This module defines functions and classes which implement a flexible
event logging system for applications and libraries.

The key benefit of having the logging API provided by a standard library
module is that all Python modules can participate in logging, so your
application log can include your own messages integrated with messages
from third-party modules.

Here’s a simple example of idiomatic usage:

     # myapp.py
     import logging
     import mylib
     logger = logging.getLogger(__name__)

     def main():
         logging.basicConfig(filename='myapp.log', level=logging.INFO)
         logger.info('Started')
         mylib.do_something()
         logger.info('Finished')

     if __name__ == '__main__':
         main()

     # mylib.py
     import logging
     logger = logging.getLogger(__name__)

     def do_something():
         logger.info('Doing something')

If you run 'myapp.py', you should see this in 'myapp.log':

     INFO:__main__:Started
     INFO:mylib:Doing something
     INFO:__main__:Finished

The key feature of this idiomatic usage is that the majority of code is
simply creating a module level logger with ‘getLogger(__name__)’, and
using that logger to do any needed logging.  This is concise, while
allowing downstream code fine-grained control if needed.  Logged
messages to the module-level logger get forwarded to handlers of loggers
in higher-level modules, all the way up to the highest-level logger
known as the root logger; this approach is known as hierarchical
logging.

For logging to be useful, it needs to be configured: setting the levels
and destinations for each logger, potentially changing how specific
modules log, often based on command-line arguments or application
configuration.  In most cases, like the one above, only the root logger
needs to be so configured, since all the lower level loggers at module
level eventually forward their messages to its handlers.  *note
basicConfig(): a0b. provides a quick way to configure the root logger
that handles many use cases.

The module provides a lot of functionality and flexibility.  If you are
unfamiliar with logging, the best way to get to grips with it is to view
the tutorials ('see the links above and on the right').

The basic classes defined by the module, together with their attributes
and methods, are listed in the sections below.

   * Loggers expose the interface that application code directly uses.

   * Handlers send the log records (created by loggers) to the
     appropriate destination.

   * Filters provide a finer grained facility for determining which log
     records to output.

   * Formatters specify the layout of log records in the final output.

* Menu:

* Logger Objects::
* Logging Levels::
* Handler Objects::
* Formatter Objects::
* Filter Objects::
* LogRecord Objects::
* LogRecord attributes::
* LoggerAdapter Objects::
* Thread Safety::
* Module-Level Functions::
* Module-Level Attributes::
* Integration with the warnings module::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/logging/__init__.py


File: python.info,  Node: Logger Objects,  Next: Logging Levels,  Up: logging — Logging facility for Python

5.16.4.1 Logger Objects
.......................

Loggers have the following attributes and methods.  Note that Loggers
should 'NEVER' be instantiated directly, but always through the
module-level function ‘logging.getLogger(name)’.  Multiple calls to
*note getLogger(): 96a. with the same name will always return a
reference to the same Logger object.

The ‘name’ is potentially a period-separated hierarchical value, like
‘foo.bar.baz’ (though it could also be just plain ‘foo’, for example).
Loggers that are further down in the hierarchical list are children of
loggers higher up in the list.  For example, given a logger with a name
of ‘foo’, loggers with names of ‘foo.bar’, ‘foo.bar.baz’, and ‘foo.bam’
are all descendants of ‘foo’.  In addition, all loggers are descendants
of the root logger.  The logger name hierarchy is analogous to the
Python package hierarchy, and identical to it if you organise your
loggers on a per-module basis using the recommended construction
‘logging.getLogger(__name__)’.  That’s because in a module, ‘__name__’
is the module’s name in the Python package namespace.

 -- Class: logging.Logger

      -- Attribute: name

          This is the logger’s name, and is the value that was passed to
          *note getLogger(): 96a. to obtain the logger.

               Note: This attribute should be treated as read-only.

      -- Attribute: level

          The threshold of this logger, as set by the *note setLevel():
          14e2. method.

               Note: Do not set this attribute directly - always use
               *note setLevel(): 14e2, which has checks for the level
               passed to it.

      -- Attribute: parent

          The parent logger of this logger.  It may change based on
          later instantiation of loggers which are higher up in the
          namespace hierarchy.

               Note: This value should be treated as read-only.

      -- Attribute: propagate

          If this attribute evaluates to true, events logged to this
          logger will be passed to the handlers of higher level
          (ancestor) loggers, in addition to any handlers attached to
          this logger.  Messages are passed directly to the ancestor
          loggers’ handlers - neither the level nor filters of the
          ancestor loggers in question are considered.

          If this evaluates to false, logging messages are not passed to
          the handlers of ancestor loggers.

          Spelling it out with an example: If the propagate attribute of
          the logger named ‘A.B.C’ evaluates to true, any event logged
          to ‘A.B.C’ via a method call such as
          ‘logging.getLogger('A.B.C').error(...)’ will [subject to
          passing that logger’s level and filter settings] be passed in
          turn to any handlers attached to loggers named ‘A.B’, ‘A’ and
          the root logger, after first being passed to any handlers
          attached to ‘A.B.C’.  If any logger in the chain ‘A.B.C’,
          ‘A.B’, ‘A’ has its ‘propagate’ attribute set to false, then
          that is the last logger whose handlers are offered the event
          to handle, and propagation stops at that point.

          The constructor sets this attribute to ‘True’.

               Note: If you attach a handler to a logger 'and' one or
               more of its ancestors, it may emit the same record
               multiple times.  In general, you should not need to
               attach a handler to more than one logger - if you just
               attach it to the appropriate logger which is highest in
               the logger hierarchy, then it will see all events logged
               by all descendant loggers, provided that their propagate
               setting is left set to ‘True’.  A common scenario is to
               attach handlers only to the root logger, and to let
               propagation take care of the rest.

      -- Attribute: handlers

          The list of handlers directly attached to this logger
          instance.

               Note: This attribute should be treated as read-only; it
               is normally changed via the *note addHandler(): 2e53. and
               *note removeHandler(): 2e54. methods, which use locks to
               ensure thread-safe operation.

      -- Attribute: disabled

          This attribute disables handling of any events.  It is set to
          ‘False’ in the initializer, and only changed by logging
          configuration code.

               Note: This attribute should be treated as read-only.

      -- Method: setLevel (level)

          Sets the threshold for this logger to 'level'.  Logging
          messages which are less severe than 'level' will be ignored;
          logging messages which have severity 'level' or higher will be
          emitted by whichever handler or handlers service this logger,
          unless a handler’s level has been set to a higher severity
          level than 'level'.

          When a logger is created, the level is set to *note NOTSET:
          2e56. (which causes all messages to be processed when the
          logger is the root logger, or delegation to the parent when
          the logger is a non-root logger).  Note that the root logger
          is created with level *note WARNING: 1e97.

          The term ‘delegation to the parent’ means that if a logger has
          a level of NOTSET, its chain of ancestor loggers is traversed
          until either an ancestor with a level other than NOTSET is
          found, or the root is reached.

          If an ancestor is found with a level other than NOTSET, then
          that ancestor’s level is treated as the effective level of the
          logger where the ancestor search began, and is used to
          determine how a logging event is handled.

          If the root is reached, and it has a level of NOTSET, then all
          messages will be processed.  Otherwise, the root’s level will
          be used as the effective level.

          See *note Logging Levels: 65d. for a list of levels.

          Changed in version 3.2: The 'level' parameter now accepts a
          string representation of the level such as ‘INFO’ as an
          alternative to the integer constants such as *note INFO: 1e96.
          Note, however, that levels are internally stored as integers,
          and methods such as e.g.  *note getEffectiveLevel(): 2e57. and
          *note isEnabledFor(): 133f. will return/expect to be passed
          integers.

      -- Method: isEnabledFor (level)

          Indicates if a message of severity 'level' would be processed
          by this logger.  This method checks first the module-level
          level set by ‘logging.disable(level)’ and then the logger’s
          effective level as determined by *note getEffectiveLevel():
          2e57.

      -- Method: getEffectiveLevel ()

          Indicates the effective level for this logger.  If a value
          other than *note NOTSET: 2e56. has been set using *note
          setLevel(): 14e2, it is returned.  Otherwise, the hierarchy is
          traversed towards the root until a value other than ‘NOTSET’
          is found, and that value is returned.  The value returned is
          an integer, typically one of *note logging.DEBUG: 1e95, *note
          logging.INFO: 1e96. etc.

      -- Method: getChild (suffix)

          Returns a logger which is a descendant to this logger, as
          determined by the suffix.  Thus,
          ‘logging.getLogger('abc').getChild('def.ghi')’ would return
          the same logger as would be returned by
          ‘logging.getLogger('abc.def.ghi')’.  This is a convenience
          method, useful when the parent logger is named using e.g.
          ‘__name__’ rather than a literal string.

          Added in version 3.2.

      -- Method: getChildren ()

          Returns a set of loggers which are immediate children of this
          logger.  So for example ‘logging.getLogger().getChildren()’
          might return a set containing loggers named ‘foo’ and ‘bar’,
          but a logger named ‘foo.bar’ wouldn’t be included in the set.
          Likewise, ‘logging.getLogger('foo').getChildren()’ might
          return a set including a logger named ‘foo.bar’, but it
          wouldn’t include one named ‘foo.bar.baz’.

          Added in version 3.12.

      -- Method: debug (msg, *args, **kwargs)

          Logs a message with level *note DEBUG: 1e95. on this logger.
          The 'msg' is the message format string, and the 'args' are the
          arguments which are merged into 'msg' using the string
          formatting operator.  (Note that this means that you can use
          keywords in the format string, together with a single
          dictionary argument.)  No % formatting operation is performed
          on 'msg' when no 'args' are supplied.

          There are four keyword arguments in 'kwargs' which are
          inspected: 'exc_info', 'stack_info', 'stacklevel' and 'extra'.

          If 'exc_info' does not evaluate as false, it causes exception
          information to be added to the logging message.  If an
          exception tuple (in the format returned by *note
          sys.exc_info(): 68d.) or an exception instance is provided, it
          is used; otherwise, ‘sys.exc_info()’ is called to get the
          exception information.

          The second optional keyword argument is 'stack_info', which
          defaults to ‘False’.  If true, stack information is added to
          the logging message, including the actual logging call.  Note
          that this is not the same stack information as that displayed
          through specifying 'exc_info': The former is stack frames from
          the bottom of the stack up to the logging call in the current
          thread, whereas the latter is information about stack frames
          which have been unwound, following an exception, while
          searching for exception handlers.

          You can specify 'stack_info' independently of 'exc_info', e.g.
          to just show how you got to a certain point in your code, even
          when no exceptions were raised.  The stack frames are printed
          following a header line which says:

               Stack (most recent call last):

          This mimics the ‘Traceback (most recent call last):’ which is
          used when displaying exception frames.

          The third optional keyword argument is 'stacklevel', which
          defaults to ‘1’.  If greater than 1, the corresponding number
          of stack frames are skipped when computing the line number and
          function name set in the *note LogRecord: 1021. created for
          the logging event.  This can be used in logging helpers so
          that the function name, filename and line number recorded are
          not the information for the helper function/method, but rather
          its caller.  The name of this parameter mirrors the equivalent
          one in the *note warnings: 112. module.

          The fourth keyword argument is 'extra' which can be used to
          pass a dictionary which is used to populate the *note
          __dict__: 55e. of the *note LogRecord: 1021. created for the
          logging event with user-defined attributes.  These custom
          attributes can then be used as you like.  For example, they
          could be incorporated into logged messages.  For example:

               FORMAT = '%(asctime)s %(clientip)-15s %(user)-8s %(message)s'
               logging.basicConfig(format=FORMAT)
               d = {'clientip': '192.168.0.1', 'user': 'fbloggs'}
               logger = logging.getLogger('tcpserver')
               logger.warning('Protocol problem: %s', 'connection reset', extra=d)

          would print something like

               2006-02-08 22:20:02,165 192.168.0.1 fbloggs  Protocol problem: connection reset

          The keys in the dictionary passed in 'extra' should not clash
          with the keys used by the logging system.  (See the section on
          *note LogRecord attributes: 2e58. for more information on
          which keys are used by the logging system.)

          If you choose to use these attributes in logged messages, you
          need to exercise some care.  In the above example, for
          instance, the *note Formatter: 14e6. has been set up with a
          format string which expects ‘clientip’ and ‘user’ in the
          attribute dictionary of the *note LogRecord: 1021.  If these
          are missing, the message will not be logged because a string
          formatting exception will occur.  So in this case, you always
          need to pass the 'extra' dictionary with these keys.

          While this might be annoying, this feature is intended for use
          in specialized circumstances, such as multi-threaded servers
          where the same code executes in many contexts, and interesting
          conditions which arise are dependent on this context (such as
          remote client IP address and authenticated user name, in the
          above example).  In such circumstances, it is likely that
          specialized *note Formatter: 14e6.s would be used with
          particular *note Handler: 14e5.s.

          If no handler is attached to this logger (or any of its
          ancestors, taking into account the relevant *note
          Logger.propagate: 14e4. attributes), the message will be sent
          to the handler set on *note lastResort: 123f.

          Changed in version 3.2: The 'stack_info' parameter was added.

          Changed in version 3.5: The 'exc_info' parameter can now
          accept exception instances.

          Changed in version 3.8: The 'stacklevel' parameter was added.

      -- Method: info (msg, *args, **kwargs)

          Logs a message with level *note INFO: 1e96. on this logger.
          The arguments are interpreted as for *note debug(): 2e5a.

      -- Method: warning (msg, *args, **kwargs)

          Logs a message with level *note WARNING: 1e97. on this logger.
          The arguments are interpreted as for *note debug(): 2e5a.

               Note: There is an obsolete method ‘warn’ which is
               functionally identical to ‘warning’.  As ‘warn’ is
               deprecated, please do not use it - use ‘warning’ instead.

      -- Method: error (msg, *args, **kwargs)

          Logs a message with level *note ERROR: 1e98. on this logger.
          The arguments are interpreted as for *note debug(): 2e5a.

      -- Method: critical (msg, *args, **kwargs)

          Logs a message with level *note CRITICAL: 1e99. on this
          logger.  The arguments are interpreted as for *note debug():
          2e5a.

      -- Method: log (level, msg, *args, **kwargs)

          Logs a message with integer level 'level' on this logger.  The
          other arguments are interpreted as for *note debug(): 2e5a.

      -- Method: exception (msg, *args, **kwargs)

          Logs a message with level *note ERROR: 1e98. on this logger.
          The arguments are interpreted as for *note debug(): 2e5a.
          Exception info is added to the logging message.  This method
          should only be called from an exception handler.

      -- Method: addFilter (filter)

          Adds the specified filter 'filter' to this logger.

      -- Method: removeFilter (filter)

          Removes the specified filter 'filter' from this logger.

      -- Method: filter (record)

          Apply this logger’s filters to the record and return ‘True’ if
          the record is to be processed.  The filters are consulted in
          turn, until one of them returns a false value.  If none of
          them return a false value, the record will be processed
          (passed to handlers).  If one returns a false value, no
          further processing of the record occurs.

      -- Method: addHandler (hdlr)

          Adds the specified handler 'hdlr' to this logger.

      -- Method: removeHandler (hdlr)

          Removes the specified handler 'hdlr' from this logger.

      -- Method: findCaller (stack_info=False, stacklevel=1)

          Finds the caller’s source filename and line number.  Returns
          the filename, line number, function name and stack information
          as a 4-element tuple.  The stack information is returned as
          ‘None’ unless 'stack_info' is ‘True’.

          The 'stacklevel' parameter is passed from code calling the
          *note debug(): 2e5a. and other APIs.  If greater than 1, the
          excess is used to skip stack frames before determining the
          values to be returned.  This will generally be useful when
          calling logging APIs from helper/wrapper code, so that the
          information in the event log refers not to the helper/wrapper
          code, but to the code that calls it.

      -- Method: handle (record)

          Handles a record by passing it to all handlers associated with
          this logger and its ancestors (until a false value of
          'propagate' is found).  This method is used for unpickled
          records received from a socket, as well as those created
          locally.  Logger-level filtering is applied using *note
          filter(): 2e5e.

      -- Method: makeRecord (name, level, fn, lno, msg, args, exc_info,
               func=None, extra=None, sinfo=None)

          This is a factory method which can be overridden in subclasses
          to create specialized *note LogRecord: 1021. instances.

      -- Method: hasHandlers ()

          Checks to see if this logger has any handlers configured.
          This is done by looking for handlers in this logger and its
          parents in the logger hierarchy.  Returns ‘True’ if a handler
          was found, else ‘False’.  The method stops searching up the
          hierarchy whenever a logger with the ‘propagate’ attribute set
          to false is found - that will be the last logger which is
          checked for the existence of handlers.

          Added in version 3.2.

     Changed in version 3.7: Loggers can now be pickled and unpickled.


File: python.info,  Node: Logging Levels,  Next: Handler Objects,  Prev: Logger Objects,  Up: logging — Logging facility for Python

5.16.4.2 Logging Levels
.......................

The numeric values of logging levels are given in the following table.
These are primarily of interest if you want to define your own levels,
and need them to have specific values relative to the predefined levels.
If you define a level with the same numeric value, it overwrites the
predefined value; the predefined name is lost.

Level                       Numeric value       What it means / When to use it
                                                
------------------------------------------------------------------------------------------
                                                
 -- Data: logging.NOTSET    0                   When set on a logger, indicates that
                                                ancestor loggers are to be consulted to
                                                determine the effective level.  If that
                                                still resolves to ‘NOTSET’, then all
                                                events are logged.  When set on a
                                                handler, all events are handled.
                                                
                                                
 -- Data: logging.DEBUG     10                  Detailed information, typically only of
                                                interest to a developer trying to
                                                diagnose a problem.
                                                
                                                
 -- Data: logging.INFO      20                  Confirmation that things are working as
                                                expected.
                                                
                                                
 -- Data: logging.WARNING   30                  An indication that something unexpected
                                                happened, or that a problem might occur
                                                in the near future (e.g.  ‘disk space
                                                low’).  The software is still working
                                                as expected.
                                                
                                                
 -- Data: logging.ERROR     40                  Due to a more serious problem, the
                                                software has not been able to perform
                                                some function.
                                                
                                                
 -- Data:                   50                  A serious error, indicating that the
          logging.CRITICAL                      program itself may be unable to
                                                continue running.
                                                


File: python.info,  Node: Handler Objects,  Next: Formatter Objects,  Prev: Logging Levels,  Up: logging — Logging facility for Python

5.16.4.3 Handler Objects
........................

Handlers have the following attributes and methods.  Note that *note
Handler: 14e5. is never instantiated directly; this class acts as a base
for more useful subclasses.  However, the ‘__init__()’ method in
subclasses needs to call *note Handler.__init__(): 2e66.

 -- Class: logging.Handler

      -- Method: __init__ (level=NOTSET)

          Initializes the ‘Handler’ instance by setting its level,
          setting the list of filters to the empty list and creating a
          lock (using *note createLock(): 2e67.) for serializing access
          to an I/O mechanism.

      -- Method: createLock ()

          Initializes a thread lock which can be used to serialize
          access to underlying I/O functionality which may not be
          threadsafe.

      -- Method: acquire ()

          Acquires the thread lock created with *note createLock():
          2e67.

      -- Method: release ()

          Releases the thread lock acquired with *note acquire(): 2e68.

      -- Method: setLevel (level)

          Sets the threshold for this handler to 'level'.  Logging
          messages which are less severe than 'level' will be ignored.
          When a handler is created, the level is set to *note NOTSET:
          2e56. (which causes all messages to be processed).

          See *note Logging Levels: 65d. for a list of levels.

          Changed in version 3.2: The 'level' parameter now accepts a
          string representation of the level such as ‘INFO’ as an
          alternative to the integer constants such as *note INFO: 1e96.

      -- Method: setFormatter (fmt)

          Sets the formatter for this handler to 'fmt'.  The 'fmt'
          argument must be a *note Formatter: 14e6. instance or ‘None’.

      -- Method: addFilter (filter)

          Adds the specified filter 'filter' to this handler.

      -- Method: removeFilter (filter)

          Removes the specified filter 'filter' from this handler.

      -- Method: filter (record)

          Apply this handler’s filters to the record and return ‘True’
          if the record is to be processed.  The filters are consulted
          in turn, until one of them returns a false value.  If none of
          them return a false value, the record will be emitted.  If one
          returns a false value, the handler will not emit the record.

      -- Method: flush ()

          Ensure all logging output has been flushed.  This version does
          nothing and is intended to be implemented by subclasses.

      -- Method: close ()

          Tidy up any resources used by the handler.  This version does
          no output but removes the handler from an internal map of
          handlers, which is used for handler lookup by name.

          Subclasses should ensure that this gets called from overridden
          ‘close()’ methods.

      -- Method: handle (record)

          Conditionally emits the specified logging record, depending on
          filters which may have been added to the handler.  Wraps the
          actual emission of the record with acquisition/release of the
          I/O thread lock.

      -- Method: handleError (record)

          This method should be called from handlers when an exception
          is encountered during an *note emit(): 2e73. call.  If the
          module-level attribute *note raiseExceptions: 123e. is
          ‘False’, exceptions get silently ignored.  This is what is
          mostly wanted for a logging system - most users will not care
          about errors in the logging system, they are more interested
          in application errors.  You could, however, replace this with
          a custom handler if you wish.  The specified record is the one
          which was being processed when the exception occurred.  (The
          default value of ‘raiseExceptions’ is ‘True’, as that is more
          useful during development).

      -- Method: format (record)

          Do formatting for a record - if a formatter is set, use it.
          Otherwise, use the default formatter for the module.

      -- Method: emit (record)

          Do whatever it takes to actually log the specified logging
          record.  This version is intended to be implemented by
          subclasses and so raises a *note NotImplementedError: 228.

               Warning: This method is called after a handler-level lock
               is acquired, which is released after this method returns.
               When you override this method, note that you should be
               careful when calling anything that invokes other parts of
               the logging API which might do locking, because that
               might result in a deadlock.  Specifically:

                  * Logging configuration APIs acquire the module-level
                    lock, and then individual handler-level locks as
                    those handlers are configured.

                  * Many logging APIs lock the module-level lock.  If
                    such an API is called from this method, it could
                    cause a deadlock if a configuration call is made on
                    another thread, because that thread will try to
                    acquire the module-level lock 'before' the
                    handler-level lock, whereas this thread tries to
                    acquire the module-level lock 'after' the
                    handler-level lock (because in this method, the
                    handler-level lock has already been acquired).

For a list of handlers included as standard, see *note logging.handlers:
89.


File: python.info,  Node: Formatter Objects,  Next: Filter Objects,  Prev: Handler Objects,  Up: logging — Logging facility for Python

5.16.4.4 Formatter Objects
..........................

 -- Class: logging.Formatter (fmt=None, datefmt=None, style='%',
          validate=True, *, defaults=None)

     Responsible for converting a *note LogRecord: 1021. to an output
     string to be interpreted by a human or external system.


     Parameters:

        * ‘fmt’ (*note str: 44f.) – A format string in the given 'style'
          for the logged output as a whole.  The possible mapping keys
          are drawn from the *note LogRecord: 1021. object’s *note
          LogRecord attributes: 2e58.  If not specified, ‘'%(message)s'’
          is used, which is just the logged message.

        * ‘datefmt’ (*note str: 44f.) – A format string for the
          date/time portion of the logged output.  If not specified, the
          default described in *note formatTime(): 2e77. is used.

        * ‘style’ (*note str: 44f.) – Can be one of ‘'%'’, ‘'{'’ or
          ‘'$'’ and determines how the format string will be merged with
          its data: using one of *note printf-style String Formatting:
          6cf. (‘%’), *note str.format(): 624. (‘{’) or *note
          string.Template: 68a. (‘$’).  This only applies to 'fmt' (e.g.
          ‘'%(message)s'’ versus ‘'{message}'’), not to the actual log
          messages passed to the logging methods.  However, there are
          *note other ways: 2e78. to use ‘{’- and ‘$’-formatting for log
          messages.

        * ‘validate’ (*note bool: 46b.) – If ‘True’ (the default),
          incorrect or mismatched 'fmt' and 'style' will raise a *note
          ValueError: 202.; for example, ‘logging.Formatter('%(asctime)s
          - %(message)s', style='{')’.

        * ‘defaults’ (*note dict: 256.‘[’*note str: 44f.‘, ’‘Any’‘]’) –
          A dictionary with default values to use in custom fields.  For
          example, ‘logging.Formatter('%(ip)s %(message)s',
          defaults={"ip": None})’

     Changed in version 3.2: Added the 'style' parameter.

     Changed in version 3.8: Added the 'validate' parameter.

     Changed in version 3.10: Added the 'defaults' parameter.

      -- Method: format (record)

          The record’s attribute dictionary is used as the operand to a
          string formatting operation.  Returns the resulting string.
          Before formatting the dictionary, a couple of preparatory
          steps are carried out.  The 'message' attribute of the record
          is computed using 'msg' % 'args'.  If the formatting string
          contains ‘'(asctime)'’, *note formatTime(): 2e77. is called to
          format the event time.  If there is exception information, it
          is formatted using *note formatException(): 2e7a. and appended
          to the message.  Note that the formatted exception information
          is cached in attribute 'exc_text'.  This is useful because the
          exception information can be pickled and sent across the wire,
          but you should be careful if you have more than one
          ‘Formatter’ subclass which customizes the formatting of
          exception information.  In this case, you will have to clear
          the cached value (by setting the 'exc_text' attribute to
          ‘None’) after a formatter has done its formatting, so that the
          next formatter to handle the event doesn’t use the cached
          value, but recalculates it afresh.

          If stack information is available, it’s appended after the
          exception information, using *note formatStack(): 2e7b. to
          transform it if necessary.

      -- Method: formatTime (record, datefmt=None)

          This method should be called from *note format(): 622. by a
          formatter which wants to make use of a formatted time.  This
          method can be overridden in formatters to provide for any
          specific requirement, but the basic behavior is as follows: if
          'datefmt' (a string) is specified, it is used with *note
          time.strftime(): 122e. to format the creation time of the
          record.  Otherwise, the format ‘%Y-%m-%d %H:%M:%S,uuu’ is
          used, where the uuu part is a millisecond value and the other
          letters are as per the ‘time.strftime()’ documentation.  An
          example time in this format is ‘2003-01-23 00:29:50,411’.  The
          resulting string is returned.

          This function uses a user-configurable function to convert the
          creation time to a tuple.  By default, *note time.localtime():
          1548. is used; to change this for a particular formatter
          instance, set the ‘converter’ attribute to a function with the
          same signature as ‘time.localtime()’ or *note time.gmtime():
          1205.  To change it for all formatters, for example if you
          want all logging times to be shown in GMT, set the ‘converter’
          attribute in the ‘Formatter’ class.

          Changed in version 3.3: Previously, the default format was
          hard-coded as in this example: ‘2010-09-06 22:38:15,292’ where
          the part before the comma is handled by a strptime format
          string (‘'%Y-%m-%d %H:%M:%S'’), and the part after the comma
          is a millisecond value.  Because strptime does not have a
          format placeholder for milliseconds, the millisecond value is
          appended using another format string, ‘'%s,%03d'’ — and both
          of these format strings have been hardcoded into this method.
          With the change, these strings are defined as class-level
          attributes which can be overridden at the instance level when
          desired.  The names of the attributes are
          ‘default_time_format’ (for the strptime format string) and
          ‘default_msec_format’ (for appending the millisecond value).

          Changed in version 3.9: The ‘default_msec_format’ can be
          ‘None’.

      -- Method: formatException (exc_info)

          Formats the specified exception information (a standard
          exception tuple as returned by *note sys.exc_info(): 68d.) as
          a string.  This default implementation just uses *note
          traceback.print_exception(): 855.  The resulting string is
          returned.

      -- Method: formatStack (stack_info)

          Formats the specified stack information (a string as returned
          by *note traceback.print_stack(): eba, but with the last
          newline removed) as a string.  This default implementation
          just returns the input value.

 -- Class: logging.BufferingFormatter (linefmt=None)

     A base formatter class suitable for subclassing when you want to
     format a number of records.  You can pass a *note Formatter: 14e6.
     instance which you want to use to format each line (that
     corresponds to a single record).  If not specified, the default
     formatter (which just outputs the event message) is used as the
     line formatter.

      -- Method: formatHeader (records)

          Return a header for a list of 'records'.  The base
          implementation just returns the empty string.  You will need
          to override this method if you want specific behaviour, e.g.
          to show the count of records, a title or a separator line.

      -- Method: formatFooter (records)

          Return a footer for a list of 'records'.  The base
          implementation just returns the empty string.  You will need
          to override this method if you want specific behaviour, e.g.
          to show the count of records or a separator line.

      -- Method: format (records)

          Return formatted text for a list of 'records'.  The base
          implementation just returns the empty string if there are no
          records; otherwise, it returns the concatenation of the
          header, each record formatted with the line formatter, and the
          footer.


File: python.info,  Node: Filter Objects,  Next: LogRecord Objects,  Prev: Formatter Objects,  Up: logging — Logging facility for Python

5.16.4.5 Filter Objects
.......................

‘Filters’ can be used by ‘Handlers’ and ‘Loggers’ for more sophisticated
filtering than is provided by levels.  The base filter class only allows
events which are below a certain point in the logger hierarchy.  For
example, a filter initialized with ‘A.B’ will allow events logged by
loggers ‘A.B’, ‘A.B.C’, ‘A.B.C.D’, ‘A.B.D’ etc.  but not ‘A.BB’, ‘B.A.B’
etc.  If initialized with the empty string, all events are passed.

 -- Class: logging.Filter (name='')

     Returns an instance of the ‘Filter’ class.  If 'name' is specified,
     it names a logger which, together with its children, will have its
     events allowed through the filter.  If 'name' is the empty string,
     allows every event.

      -- Method: filter (record)

          Is the specified record to be logged?  Returns false for no,
          true for yes.  Filters can either modify log records in-place
          or return a completely different record instance which will
          replace the original log record in any future processing of
          the event.

Note that filters attached to handlers are consulted before an event is
emitted by the handler, whereas filters attached to loggers are
consulted whenever an event is logged (using *note debug(): 2e5a, *note
info(): 2e83, etc.), before sending an event to handlers.  This means
that events which have been generated by descendant loggers will not be
filtered by a logger’s filter setting, unless the filter has also been
applied to those descendant loggers.

You don’t actually need to subclass ‘Filter’: you can pass any instance
which has a ‘filter’ method with the same semantics.

Changed in version 3.2: You don’t need to create specialized ‘Filter’
classes, or use other classes with a ‘filter’ method: you can use a
function (or other callable) as a filter.  The filtering logic will
check to see if the filter object has a ‘filter’ attribute: if it does,
it’s assumed to be a ‘Filter’ and its *note filter(): 2e82. method is
called.  Otherwise, it’s assumed to be a callable and called with the
record as the single parameter.  The returned value should conform to
that returned by ‘filter()’.

Changed in version 3.12: You can now return a *note LogRecord: 1021.
instance from filters to replace the log record rather than modifying it
in place.  This allows filters attached to a *note Handler: 14e5. to
modify the log record before it is emitted, without having side effects
on other handlers.

Although filters are used primarily to filter records based on more
sophisticated criteria than levels, they get to see every record which
is processed by the handler or logger they’re attached to: this can be
useful if you want to do things like counting how many records were
processed by a particular logger or handler, or adding, changing or
removing attributes in the *note LogRecord: 1021. being processed.
Obviously changing the LogRecord needs to be done with some care, but it
does allow the injection of contextual information into logs (see *note
Using Filters to impart contextual information: 2e84.).


File: python.info,  Node: LogRecord Objects,  Next: LogRecord attributes,  Prev: Filter Objects,  Up: logging — Logging facility for Python

5.16.4.6 LogRecord Objects
..........................

*note LogRecord: 1021. instances are created automatically by the *note
Logger: b6a. every time something is logged, and can be created manually
via *note makeLogRecord(): 2e87. (for example, from a pickled event
received over the wire).

 -- Class: logging.LogRecord (name, level, pathname, lineno, msg, args,
          exc_info, func=None, sinfo=None)

     Contains all the information pertinent to the event being logged.

     The primary information is passed in 'msg' and 'args', which are
     combined using ‘msg % args’ to create the ‘message’ attribute of
     the record.


     Parameters:

        * ‘name’ (*note str: 44f.) – The name of the logger used to log
          the event represented by this ‘LogRecord’.  Note that the
          logger name in the ‘LogRecord’ will always have this value,
          even though it may be emitted by a handler attached to a
          different (ancestor) logger.

        * ‘level’ (*note int: 257.) – The *note numeric level: 65d. of
          the logging event (such as ‘10’ for ‘DEBUG’, ‘20’ for ‘INFO’,
          etc).  Note that this is converted to 'two' attributes of the
          LogRecord: ‘levelno’ for the numeric value and ‘levelname’ for
          the corresponding level name.

        * ‘pathname’ (*note str: 44f.) – The full string path of the
          source file where the logging call was made.

        * ‘lineno’ (*note int: 257.) – The line number in the source
          file where the logging call was made.

        * ‘msg’ (*note Any: 6af.) – The event description message, which
          can be a %-format string with placeholders for variable data,
          or an arbitrary object (see *note Using arbitrary objects as
          messages: 2e88.).

        * ‘args’ (*note tuple: 373.‘ | ’*note dict: 256.‘[’*note str:
          44f.‘, ’*note Any: 6af.‘]’) – Variable data to merge into the
          'msg' argument to obtain the event description.

        * ‘exc_info’ (*note tuple: 373.‘[’*note type: d71.‘[’*note
          BaseException: 5be.‘]’‘, ’‘BaseException’‘, ’*note
          types.TracebackType: b0b.‘] ’‘| ’‘None’) – An exception tuple
          with the current exception information, as returned by *note
          sys.exc_info(): 68d, or ‘None’ if no exception information is
          available.

        * ‘func’ (*note str: 44f.‘ | ’‘None’) – The name of the function
          or method from which the logging call was invoked.

        * ‘sinfo’ (*note str: 44f.‘ | ’‘None’) – A text string
          representing stack information from the base of the stack in
          the current thread, up to the logging call.

      -- Method: getMessage ()

          Returns the message for this ‘LogRecord’ instance after
          merging any user-supplied arguments with the message.  If the
          user-supplied message argument to the logging call is not a
          string, *note str(): 44f. is called on it to convert it to a
          string.  This allows use of user-defined classes as messages,
          whose ‘__str__’ method can return the actual format string to
          be used.

     Changed in version 3.2: The creation of a ‘LogRecord’ has been made
     more configurable by providing a factory which is used to create
     the record.  The factory can be set using *note
     getLogRecordFactory(): 2e8a. and *note setLogRecordFactory(): 2e8b.
     (see this for the factory’s signature).

     This functionality can be used to inject your own values into a
     ‘LogRecord’ at creation time.  You can use the following pattern:

          old_factory = logging.getLogRecordFactory()

          def record_factory(*args, **kwargs):
              record = old_factory(*args, **kwargs)
              record.custom_attribute = 0xdecafbad
              return record

          logging.setLogRecordFactory(record_factory)

     With this pattern, multiple factories could be chained, and as long
     as they don’t overwrite each other’s attributes or unintentionally
     overwrite the standard attributes listed above, there should be no
     surprises.


File: python.info,  Node: LogRecord attributes,  Next: LoggerAdapter Objects,  Prev: LogRecord Objects,  Up: logging — Logging facility for Python

5.16.4.7 LogRecord attributes
.............................

The LogRecord has a number of attributes, most of which are derived from
the parameters to the constructor.  (Note that the names do not always
correspond exactly between the LogRecord constructor parameters and the
LogRecord attributes.)  These attributes can be used to merge data from
the record into the format string.  The following table lists (in
alphabetical order) the attribute names, their meanings and the
corresponding placeholder in a %-style format string.

If you are using {}-formatting (*note str.format(): 624.), you can use
‘{attrname}’ as the placeholder in the format string.  If you are using
$-formatting (*note string.Template: 68a.), use the form ‘${attrname}’.
In both cases, of course, replace ‘attrname’ with the actual attribute
name you want to use.

In the case of {}-formatting, you can specify formatting flags by
placing them after the attribute name, separated from it with a colon.
For example: a placeholder of ‘{msecs:03.0f}’ would format a millisecond
value of ‘4’ as ‘004’.  Refer to the *note str.format(): 624.
documentation for full details on the options available to you.

Attribute name       Format                        Description
                                                   
-------------------------------------------------------------------------------------------------------
                                                   
args                 You shouldn’t need to         The tuple of arguments merged into ‘msg’ to
                     format this yourself.         produce ‘message’, or a dict whose values are
                                                   used for the merge (when there is only one
                                                   argument, and it is a dictionary).
                                                   
                                                   
asctime              ‘%(asctime)s’                 Human-readable time when the
                                                   *note LogRecord: 1021. was created.  By default
                                                   this is of the form ‘2003-07-08 16:49:45,896’
                                                   (the numbers after the comma are millisecond
                                                   portion of the time).
                                                   
                                                   
created              ‘%(created)f’                 Time when the *note LogRecord: 1021. was created
                                                   (as returned by *note time.time_ns(): aff. /
                                                   1e9).
                                                   
                                                   
exc_info             You shouldn’t need to         Exception tuple (à la ‘sys.exc_info’) or, if no
                     format this yourself.         exception has occurred, ‘None’.
                                                   
                                                   
exc_text             You shouldn’t need to         Exception information formatted as a string.
                     format this yourself.         This is set when *note Formatter.format(): 2e79.
                                                   is invoked, or ‘None’ if no exception has
                                                   occurred.
                                                   
                                                   
filename             ‘%(filename)s’                Filename portion of ‘pathname’.
                                                   
                                                   
funcName             ‘%(funcName)s’                Name of function containing the logging call.
                                                   
                                                   
levelname            ‘%(levelname)s’               Text logging level for the message (‘'DEBUG'’,
                                                   ‘'INFO'’, ‘'WARNING'’, ‘'ERROR'’, ‘'CRITICAL'’).
                                                   
                                                   
levelno              ‘%(levelno)s’                 Numeric logging level for the message
                                                   (*note DEBUG: 1e95, *note INFO: 1e96,
                                                   *note WARNING: 1e97, *note ERROR: 1e98,
                                                   *note CRITICAL: 1e99.).
                                                   
                                                   
lineno               ‘%(lineno)d’                  Source line number where the logging call was
                                                   issued (if available).
                                                   
                                                   
message              ‘%(message)s’                 The logged message, computed as ‘msg % args’.
                                                   This is set when *note Formatter.format(): 2e79.
                                                   is invoked.
                                                   
                                                   
module               ‘%(module)s’                  Module (name portion of ‘filename’).
                                                   
                                                   
msecs                ‘%(msecs)d’                   Millisecond portion of the time when the
                                                   *note LogRecord: 1021. was created.
                                                   
                                                   
msg                  You shouldn’t need to         The format string passed in the original logging
                     format this yourself.         call.  Merged with ‘args’ to produce ‘message’,
                                                   or an arbitrary object (see
                                                   *note Using arbitrary objects as messages: 2e88.).
                                                   
                                                   
name                 ‘%(name)s’                    Name of the logger used to log the call.
                                                   
                                                   
pathname             ‘%(pathname)s’                Full pathname of the source file where the
                                                   logging call was issued (if available).
                                                   
                                                   
process              ‘%(process)d’                 Process ID (if available).
                                                   
                                                   
processName          ‘%(processName)s’             Process name (if available).
                                                   
                                                   
relativeCreated      ‘%(relativeCreated)d’         Time in milliseconds when the LogRecord was
                                                   created, relative to the time the logging module
                                                   was loaded.
                                                   
                                                   
stack_info           You shouldn’t need to         Stack frame information (where available) from
                     format this yourself.         the bottom of the stack in the current thread, up
                                                   to and including the stack frame of the logging
                                                   call which resulted in the creation of this
                                                   record.
                                                   
                                                   
thread               ‘%(thread)d’                  Thread ID (if available).
                                                   
                                                   
threadName           ‘%(threadName)s’              Thread name (if available).
                                                   
                                                   
taskName             ‘%(taskName)s’                *note asyncio.Task: 1be. name (if available).
                                                   

Changed in version 3.1: 'processName' was added.

Changed in version 3.12: 'taskName' was added.


File: python.info,  Node: LoggerAdapter Objects,  Next: Thread Safety,  Prev: LogRecord attributes,  Up: logging — Logging facility for Python

5.16.4.8 LoggerAdapter Objects
..............................

*note LoggerAdapter: 133e. instances are used to conveniently pass
contextual information into logging calls.  For a usage example, see the
section on *note adding contextual information to your logging output:
2e8f.

 -- Class: logging.LoggerAdapter (logger, extra=None, merge_extra=False)

     Returns an instance of ‘LoggerAdapter’ initialized with an
     underlying *note Logger: b6a. instance, an optional dict-like
     object ('extra'), and an optional boolean ('merge_extra')
     indicating whether or not the 'extra' argument of individual log
     calls should be merged with the ‘LoggerAdapter’ extra.  The default
     behavior is to ignore the 'extra' argument of individual log calls
     and only use the one of the ‘LoggerAdapter’ instance

      -- Method: process (msg, kwargs)

          Modifies the message and/or keyword arguments passed to a
          logging call in order to insert contextual information.  This
          implementation takes the object passed as 'extra' to the
          constructor and adds it to 'kwargs' using key ‘extra’.  The
          return value is a ('msg', 'kwargs') tuple which has the
          (possibly modified) versions of the arguments passed in.

      -- Attribute: manager

          Delegates to the underlying ‘manager’ on 'logger'.

      -- Attribute: _log

          Delegates to the underlying ‘_log()’ method on 'logger'.

     In addition to the above, ‘LoggerAdapter’ supports the following
     methods of *note Logger: b6a.: *note debug(): e5d, *note info():
     2e59, *note warning(): 1813, *note error(): 2e5b, *note
     exception(): e5b, *note critical(): e5c, *note log(): e5a, *note
     isEnabledFor(): 133f, *note getEffectiveLevel(): 2e57, *note
     setLevel(): 14e2. and *note hasHandlers(): 2e62.  These methods
     have the same signatures as their counterparts in ‘Logger’, so you
     can use the two types of instances interchangeably.

     Changed in version 3.2: The *note isEnabledFor(): 133f, *note
     getEffectiveLevel(): 2e57, *note setLevel(): 14e2. and *note
     hasHandlers(): 2e62. methods were added to ‘LoggerAdapter’.  These
     methods delegate to the underlying logger.

     Changed in version 3.6: Attribute ‘manager’ and method ‘_log()’
     were added, which delegate to the underlying logger and allow
     adapters to be nested.

     Changed in version 3.10: The 'extra' argument is now optional.

     Changed in version 3.13: The 'merge_extra' parameter was added.


File: python.info,  Node: Thread Safety,  Next: Module-Level Functions,  Prev: LoggerAdapter Objects,  Up: logging — Logging facility for Python

5.16.4.9 Thread Safety
......................

The logging module is intended to be thread-safe without any special
work needing to be done by its clients.  It achieves this through using
threading locks; there is one lock to serialize access to the module’s
shared data, and each handler also creates a lock to serialize access to
its underlying I/O.

If you are implementing asynchronous signal handlers using the *note
signal: c6. module, you may not be able to use logging from within such
handlers.  This is because lock implementations in the *note threading:
ed. module are not always re-entrant, and so cannot be invoked from such
signal handlers.


File: python.info,  Node: Module-Level Functions,  Next: Module-Level Attributes,  Prev: Thread Safety,  Up: logging — Logging facility for Python

5.16.4.10 Module-Level Functions
................................

In addition to the classes described above, there are a number of
module-level functions.

 -- Function: logging.getLogger (name=None)

     Return a logger with the specified name or, if name is ‘None’,
     return the root logger of the hierarchy.  If specified, the name is
     typically a dot-separated hierarchical name like '‘a’', '‘a.b’' or
     '‘a.b.c.d’'.  Choice of these names is entirely up to the developer
     who is using logging, though it is recommended that ‘__name__’ be
     used unless you have a specific reason for not doing that, as
     mentioned in *note Logger Objects: 2e4d.

     All calls to this function with a given name return the same logger
     instance.  This means that logger instances never need to be passed
     between different parts of an application.

 -- Function: logging.getLoggerClass ()

     Return either the standard *note Logger: b6a. class, or the last
     class passed to *note setLoggerClass(): 2e96.  This function may be
     called from within a new class definition, to ensure that
     installing a customized ‘Logger’ class will not undo customizations
     already applied by other code.  For example:

          class MyLogger(logging.getLoggerClass()):
              # ... override behaviour here

 -- Function: logging.getLogRecordFactory ()

     Return a callable which is used to create a *note LogRecord: 1021.

     Added in version 3.2: This function has been provided, along with
     *note setLogRecordFactory(): 2e8b, to allow developers more control
     over how the *note LogRecord: 1021. representing a logging event is
     constructed.

     See *note setLogRecordFactory(): 2e8b. for more information about
     the how the factory is called.

 -- Function: logging.debug (msg, *args, **kwargs)

     This is a convenience function that calls *note Logger.debug():
     e5d, on the root logger.  The handling of the arguments is in every
     way identical to what is described in that method.

     The only difference is that if the root logger has no handlers,
     then *note basicConfig(): a0b. is called, prior to calling ‘debug’
     on the root logger.

     For very short scripts or quick demonstrations of ‘logging’
     facilities, ‘debug’ and the other module-level functions may be
     convenient.  However, most programs will want to carefully and
     explicitly control the logging configuration, and should therefore
     prefer creating a module-level logger and calling *note
     Logger.debug(): e5d. (or other level-specific methods) on it, as
     described at the beginnning of this documentation.

 -- Function: logging.info (msg, *args, **kwargs)

     Logs a message with level *note INFO: 1e96. on the root logger.
     The arguments and behavior are otherwise the same as for *note
     debug(): 2e5a.

 -- Function: logging.warning (msg, *args, **kwargs)

     Logs a message with level *note WARNING: 1e97. on the root logger.
     The arguments and behavior are otherwise the same as for *note
     debug(): 2e5a.

          Note: There is an obsolete function ‘warn’ which is
          functionally identical to ‘warning’.  As ‘warn’ is deprecated,
          please do not use it - use ‘warning’ instead.

 -- Function: logging.error (msg, *args, **kwargs)

     Logs a message with level *note ERROR: 1e98. on the root logger.
     The arguments and behavior are otherwise the same as for *note
     debug(): 2e5a.

 -- Function: logging.critical (msg, *args, **kwargs)

     Logs a message with level *note CRITICAL: 1e99. on the root logger.
     The arguments and behavior are otherwise the same as for *note
     debug(): 2e5a.

 -- Function: logging.exception (msg, *args, **kwargs)

     Logs a message with level *note ERROR: 1e98. on the root logger.
     The arguments and behavior are otherwise the same as for *note
     debug(): 2e5a.  Exception info is added to the logging message.
     This function should only be called from an exception handler.

 -- Function: logging.log (level, msg, *args, **kwargs)

     Logs a message with level 'level' on the root logger.  The
     arguments and behavior are otherwise the same as for *note debug():
     2e5a.

 -- Function: logging.disable (level=CRITICAL)

     Provides an overriding level 'level' for all loggers which takes
     precedence over the logger’s own level.  When the need arises to
     temporarily throttle logging output down across the whole
     application, this function can be useful.  Its effect is to disable
     all logging calls of severity 'level' and below, so that if you
     call it with a value of INFO, then all INFO and DEBUG events would
     be discarded, whereas those of severity WARNING and above would be
     processed according to the logger’s effective level.  If
     ‘logging.disable(logging.NOTSET)’ is called, it effectively removes
     this overriding level, so that logging output again depends on the
     effective levels of individual loggers.

     Note that if you have defined any custom logging level higher than
     ‘CRITICAL’ (this is not recommended), you won’t be able to rely on
     the default value for the 'level' parameter, but will have to
     explicitly supply a suitable value.

     Changed in version 3.7: The 'level' parameter was defaulted to
     level ‘CRITICAL’.  See bpo-28524(1) for more information about this
     change.

 -- Function: logging.addLevelName (level, levelName)

     Associates level 'level' with text 'levelName' in an internal
     dictionary, which is used to map numeric levels to a textual
     representation, for example when a *note Formatter: 14e6. formats a
     message.  This function can also be used to define your own levels.
     The only constraints are that all levels used must be registered
     using this function, levels should be positive integers and they
     should increase in increasing order of severity.

          Note: If you are thinking of defining your own levels, please
          see the section on *note Custom Levels: 2e9c.

 -- Function: logging.getLevelNamesMapping ()

     Returns a mapping from level names to their corresponding logging
     levels.  For example, the string “CRITICAL” maps to *note CRITICAL:
     1e99.  The returned mapping is copied from an internal mapping on
     each call to this function.

     Added in version 3.11.

 -- Function: logging.getLevelName (level)

     Returns the textual or numeric representation of logging level
     'level'.

     If 'level' is one of the predefined levels *note CRITICAL: 1e99,
     *note ERROR: 1e98, *note WARNING: 1e97, *note INFO: 1e96. or *note
     DEBUG: 1e95. then you get the corresponding string.  If you have
     associated levels with names using *note addLevelName(): 2e9b. then
     the name you have associated with 'level' is returned.  If a
     numeric value corresponding to one of the defined levels is passed
     in, the corresponding string representation is returned.

     The 'level' parameter also accepts a string representation of the
     level such as ‘INFO’.  In such cases, this functions returns the
     corresponding numeric value of the level.

     If no matching numeric or string value is passed in, the string
     ‘Level %s’ % level is returned.

          Note: Levels are internally integers (as they need to be
          compared in the logging logic).  This function is used to
          convert between an integer level and the level name displayed
          in the formatted log output by means of the ‘%(levelname)s’
          format specifier (see *note LogRecord attributes: 2e58.), and
          vice versa.

     Changed in version 3.4: In Python versions earlier than 3.4, this
     function could also be passed a text level, and would return the
     corresponding numeric value of the level.  This undocumented
     behaviour was considered a mistake, and was removed in Python 3.4,
     but reinstated in 3.4.2 due to retain backward compatibility.

 -- Function: logging.getHandlerByName (name)

     Returns a handler with the specified 'name', or ‘None’ if there is
     no handler with that name.

     Added in version 3.12.

 -- Function: logging.getHandlerNames ()

     Returns an immutable set of all known handler names.

     Added in version 3.12.

 -- Function: logging.makeLogRecord (attrdict)

     Creates and returns a new *note LogRecord: 1021. instance whose
     attributes are defined by 'attrdict'.  This function is useful for
     taking a pickled ‘LogRecord’ attribute dictionary, sent over a
     socket, and reconstituting it as a ‘LogRecord’ instance at the
     receiving end.

 -- Function: logging.basicConfig (**kwargs)

     Does basic configuration for the logging system by creating a *note
     StreamHandler: 123d. with a default *note Formatter: 14e6. and
     adding it to the root logger.  The functions *note debug(): 2e5a,
     *note info(): 2e83, *note warning(): 2ff, *note error(): 2e97. and
     *note critical(): 2e98. will call ‘basicConfig()’ automatically if
     no handlers are defined for the root logger.

     This function does nothing if the root logger already has handlers
     configured, unless the keyword argument 'force' is set to ‘True’.

          Note: This function should be called from the main thread
          before other threads are started.  In versions of Python prior
          to 2.7.1 and 3.2, if this function is called from multiple
          threads, it is possible (in rare circumstances) that a handler
          will be added to the root logger more than once, leading to
          unexpected results such as messages being duplicated in the
          log.

     The following keyword arguments are supported.

     Format             Description
                        
     ---------------------------------------------------------------------
                        
     'filename'         Specifies that a *note FileHandler: 19f9. be
                        created, using the specified filename, rather
                        than a *note StreamHandler: 123d.
                        
                        
     'filemode'         If 'filename' is specified, open the file in
                        this *note mode: 2331.  Defaults to ‘'a'’.
                        
                        
     'format'           Use the specified format string for the
                        handler.  Defaults to attributes ‘levelname’,
                        ‘name’ and ‘message’ separated by colons.
                        
                        
     'datefmt'          Use the specified date/time format, as accepted
                        by *note time.strftime(): 122e.
                        
                        
     'style'            If 'format' is specified, use this style for
                        the format string.  One of ‘'%'’, ‘'{'’ or
                        ‘'$'’ for *note printf-style: 6cf,
                        *note str.format(): 624. or
                        *note string.Template: 68a. respectively.
                        Defaults to ‘'%'’.
                        
                        
     'level'            Set the root logger level to the specified
                        *note level: 65d.
                        
                        
     'stream'           Use the specified stream to initialize the
                        *note StreamHandler: 123d.  Note that this
                        argument is incompatible with 'filename' - if
                        both are present, a ‘ValueError’ is raised.
                        
                        
     'handlers'         If specified, this should be an iterable of
                        already created handlers to add to the root
                        logger.  Any handlers which don’t already have
                        a formatter set will be assigned the default
                        formatter created in this function.  Note that
                        this argument is incompatible with 'filename'
                        or 'stream' - if both are present, a
                        ‘ValueError’ is raised.
                        
                        
     'force'            If this keyword argument is specified as true,
                        any existing handlers attached to the root
                        logger are removed and closed, before carrying
                        out the configuration as specified by the other
                        arguments.
                        
                        
     'encoding'         If this keyword argument is specified along
                        with 'filename', its value is used when the
                        *note FileHandler: 19f9. is created, and thus
                        used when opening the output file.
                        
                        
     'errors'           If this keyword argument is specified along
                        with 'filename', its value is used when the
                        *note FileHandler: 19f9. is created, and thus
                        used when opening the output file.  If not
                        specified, the value ‘backslashreplace’ is
                        used.  Note that if ‘None’ is specified, it
                        will be passed as such to *note open(): 51f,
                        which means that it will be treated the same as
                        passing ‘errors’.
                        

     Changed in version 3.2: The 'style' argument was added.

     Changed in version 3.3: The 'handlers' argument was added.
     Additional checks were added to catch situations where incompatible
     arguments are specified (e.g.  'handlers' together with 'stream' or
     'filename', or 'stream' together with 'filename').

     Changed in version 3.8: The 'force' argument was added.

     Changed in version 3.9: The 'encoding' and 'errors' arguments were
     added.

 -- Function: logging.shutdown ()

     Informs the logging system to perform an orderly shutdown by
     flushing and closing all handlers.  This should be called at
     application exit and no further use of the logging system should be
     made after this call.

     When the logging module is imported, it registers this function as
     an exit handler (see *note atexit: c.), so normally there’s no need
     to do that manually.

 -- Function: logging.setLoggerClass (klass)

     Tells the logging system to use the class 'klass' when
     instantiating a logger.  The class should define ‘__init__()’ such
     that only a name argument is required, and the ‘__init__()’ should
     call ‘Logger.__init__()’.  This function is typically called before
     any loggers are instantiated by applications which need to use
     custom logger behavior.  After this call, as at any other time, do
     not instantiate loggers directly using the subclass: continue to
     use the *note logging.getLogger(): 96a. API to get your loggers.

 -- Function: logging.setLogRecordFactory (factory)

     Set a callable which is used to create a *note LogRecord: 1021.


     Parameters: ‘factory’ – The factory callable to be used to
     instantiate a log record.

     Added in version 3.2: This function has been provided, along with
     *note getLogRecordFactory(): 2e8a, to allow developers more control
     over how the *note LogRecord: 1021. representing a logging event is
     constructed.

     The factory has the following signature:

     ‘factory(name, level, fn, lno, msg, args, exc_info, func=None,
     sinfo=None, **kwargs)’


          name: The logger name.


          level: The logging level (numeric).


          fn: The full pathname of the file where the logging call was
          made.


          lno: The line number in the file where the logging call was
          made.


          msg: The logging message.


          args: The arguments for the logging message.


          exc_info: An exception tuple, or ‘None’.


          func: The name of the function or method which invoked the
          logging call.


          sinfo: A stack traceback such as is provided by *note
          traceback.print_stack(): eba, showing the call hierarchy.


          kwargs: Additional keyword arguments.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=28524


File: python.info,  Node: Module-Level Attributes,  Next: Integration with the warnings module,  Prev: Module-Level Functions,  Up: logging — Logging facility for Python

5.16.4.11 Module-Level Attributes
.................................

 -- Data: logging.lastResort

     A “handler of last resort” is available through this attribute.
     This is a *note StreamHandler: 123d. writing to ‘sys.stderr’ with a
     level of ‘WARNING’, and is used to handle logging events in the
     absence of any logging configuration.  The end result is to just
     print the message to ‘sys.stderr’.  This replaces the earlier error
     message saying that “no handlers could be found for logger XYZ”.
     If you need the earlier behaviour for some reason, ‘lastResort’ can
     be set to ‘None’.

     Added in version 3.2.

 -- Data: logging.raiseExceptions

     Used to see if exceptions during handling should be propagated.

     Default: ‘True’.

     If ‘raiseExceptions’ is ‘False’, exceptions get silently ignored.
     This is what is mostly wanted for a logging system - most users
     will not care about errors in the logging system, they are more
     interested in application errors.


File: python.info,  Node: Integration with the warnings module,  Prev: Module-Level Attributes,  Up: logging — Logging facility for Python

5.16.4.12 Integration with the warnings module
..............................................

The *note captureWarnings(): 2ea1. function can be used to integrate
‘logging’ with the *note warnings: 112. module.

 -- Function: logging.captureWarnings (capture)

     This function is used to turn the capture of warnings by logging on
     and off.

     If 'capture' is ‘True’, warnings issued by the *note warnings: 112.
     module will be redirected to the logging system.  Specifically, a
     warning will be formatted using *note warnings.formatwarning():
     1ba6. and the resulting string logged to a logger named
     ‘'py.warnings'’ with a severity of *note WARNING: 1e97.

     If 'capture' is ‘False’, the redirection of warnings to the logging
     system will stop, and warnings will be redirected to their original
     destinations (i.e.  those in effect before ‘captureWarnings(True)’
     was called).

See also
........

Module *note logging.config: 88.

     Configuration API for the logging module.

Module *note logging.handlers: 89.

     Useful handlers included with the logging module.

PEP 282(1) - A Logging System

     The proposal which described this feature for inclusion in the
     Python standard library.

Original Python logging package(2)

     This is the original source for the ‘logging’ package.  The version
     of the package available from this site is suitable for use with
     Python 1.5.2, 2.1.x and 2.2.x, which do not include the ‘logging’
     package in the standard library.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0282/

   (2) https://old.red-dove.com/python_logging.html


File: python.info,  Node: logging config — Logging configuration,  Next: logging handlers — Logging handlers,  Prev: logging — Logging facility for Python,  Up: Generic Operating System Services

5.16.5 ‘logging.config’ — Logging configuration
-----------------------------------------------

'Source code:' Lib/logging/config.py(1)

Important
.........

This page contains only reference information.  For tutorials, please
see

   * *note Basic Tutorial: 123a.

   * *note Advanced Tutorial: 123b.

   * *note Logging Cookbook: 123c.

__________________________________________________________________

This section describes the API for configuring the logging module.

* Menu:

* Configuration functions::
* Security considerations::
* Configuration dictionary schema::
* Configuration file format::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/logging/config.py


File: python.info,  Node: Configuration functions,  Next: Security considerations,  Up: logging config — Logging configuration

5.16.5.1 Configuration functions
................................

The following functions configure the logging module.  They are located
in the ‘logging.config’ module.  Their use is optional — you can
configure the logging module using these functions or by making calls to
the main API (defined in *note logging: 87. itself) and defining
handlers which are declared either in ‘logging’ or *note
logging.handlers: 89.

 -- Function: logging.config.dictConfig (config)

     Takes the logging configuration from a dictionary.  The contents of
     this dictionary are described in *note Configuration dictionary
     schema: 2ea6. below.

     If an error is encountered during configuration, this function will
     raise a *note ValueError: 202, *note TypeError: 2c3, *note
     AttributeError: 34e. or *note ImportError: 41c. with a suitably
     descriptive message.  The following is a (possibly incomplete) list
     of conditions which will raise an error:

        * A ‘level’ which is not a string or which is a string not
          corresponding to an actual logging level.

        * A ‘propagate’ value which is not a boolean.

        * An id which does not have a corresponding destination.

        * A non-existent handler id found during an incremental call.

        * An invalid logger name.

        * Inability to resolve to an internal or external object.

     Parsing is performed by the ‘DictConfigurator’ class, whose
     constructor is passed the dictionary used for configuration, and
     has a ‘configure()’ method.  The ‘logging.config’ module has a
     callable attribute ‘dictConfigClass’ which is initially set to
     ‘DictConfigurator’.  You can replace the value of ‘dictConfigClass’
     with a suitable implementation of your own.

     ‘dictConfig()’ calls ‘dictConfigClass’ passing the specified
     dictionary, and then calls the ‘configure()’ method on the returned
     object to put the configuration into effect:

          def dictConfig(config):
              dictConfigClass(config).configure()

     For example, a subclass of ‘DictConfigurator’ could call
     ‘DictConfigurator.__init__()’ in its own ‘__init__()’, then set up
     custom prefixes which would be usable in the subsequent
     ‘configure()’ call.  ‘dictConfigClass’ would be bound to this new
     subclass, and then ‘dictConfig()’ could be called exactly as in the
     default, uncustomized state.

     Added in version 3.2.

 -- Function: logging.config.fileConfig (fname, defaults=None,
          disable_existing_loggers=True, encoding=None)

     Reads the logging configuration from a *note configparser:
     22.-format file.  The format of the file should be as described in
     *note Configuration file format: 2ea7.  This function can be called
     several times from an application, allowing an end user to select
     from various pre-canned configurations (if the developer provides a
     mechanism to present the choices and load the chosen
     configuration).

     It will raise *note FileNotFoundError: 42e. if the file doesn’t
     exist and *note RuntimeError: 195. if the file is invalid or empty.


     Parameters:

        * ‘fname’ – A filename, or a file-like object, or an instance
          derived from *note RawConfigParser: f9d.  If a
          ‘RawConfigParser’-derived instance is passed, it is used as
          is.  Otherwise, a *note ConfigParser: 1c8. is instantiated,
          and the configuration read by it from the object passed in
          ‘fname’.  If that has a *note readline(): ba. method, it is
          assumed to be a file-like object and read using *note
          read_file(): 509.; otherwise, it is assumed to be a filename
          and passed to *note read(): 14b7.

        * ‘defaults’ – Defaults to be passed to the ‘ConfigParser’ can
          be specified in this argument.

        * ‘disable_existing_loggers’ – If specified as ‘False’, loggers
          which exist when this call is made are left enabled.  The
          default is ‘True’ because this enables old behaviour in a
          backward-compatible way.  This behaviour is to disable any
          existing non-root loggers unless they or their ancestors are
          explicitly named in the logging configuration.

        * ‘encoding’ – The encoding used to open file when 'fname' is
          filename.

     Changed in version 3.4: An instance of a subclass of *note
     RawConfigParser: f9d. is now accepted as a value for ‘fname’.  This
     facilitates:

             * Use of a configuration file where logging configuration
               is just part of the overall application configuration.

             * Use of a configuration read from a file, and then
               modified by the using application (e.g.  based on
               command-line parameters or other aspects of the runtime
               environment) before being passed to ‘fileConfig’.

     Changed in version 3.10: Added the 'encoding' parameter.

     Changed in version 3.12: An exception will be thrown if the
     provided file doesn’t exist or is invalid or empty.

 -- Function: logging.config.listen (port=DEFAULT_LOGGING_CONFIG_PORT,
          verify=None)

     Starts up a socket server on the specified port, and listens for
     new configurations.  If no port is specified, the module’s default
     ‘DEFAULT_LOGGING_CONFIG_PORT’ is used.  Logging configurations will
     be sent as a file suitable for processing by *note dictConfig():
     11f4. or *note fileConfig(): b6c.  Returns a *note Thread: 956.
     instance on which you can call *note start(): 2ea8. to start the
     server, and which you can *note join(): 1229. when appropriate.  To
     stop the server, call *note stopListening(): 2ea9.

     The ‘verify’ argument, if specified, should be a callable which
     should verify whether bytes received across the socket are valid
     and should be processed.  This could be done by encrypting and/or
     signing what is sent across the socket, such that the ‘verify’
     callable can perform signature verification and/or decryption.  The
     ‘verify’ callable is called with a single argument - the bytes
     received across the socket - and should return the bytes to be
     processed, or ‘None’ to indicate that the bytes should be
     discarded.  The returned bytes could be the same as the passed in
     bytes (e.g.  when only verification is done), or they could be
     completely different (perhaps if decryption were performed).

     To send a configuration to the socket, read in the configuration
     file and send it to the socket as a sequence of bytes preceded by a
     four-byte length string packed in binary using ‘struct.pack('>L',
     n)’.
          Note: Because portions of the configuration are passed through
          *note eval(): 180, use of this function may open its users to
          a security risk.  While the function only binds to a socket on
          ‘localhost’, and so does not accept connections from remote
          machines, there are scenarios where untrusted code could be
          run under the account of the process which calls ‘listen()’.
          Specifically, if the process calling ‘listen()’ runs on a
          multi-user machine where users cannot trust each other, then a
          malicious user could arrange to run essentially arbitrary code
          in a victim user’s process, simply by connecting to the
          victim’s ‘listen()’ socket and sending a configuration which
          runs whatever code the attacker wants to have executed in the
          victim’s process.  This is especially easy to do if the
          default port is used, but not hard even if a different port is
          used.  To avoid the risk of this happening, use the ‘verify’
          argument to ‘listen()’ to prevent unrecognised configurations
          from being applied.

     Changed in version 3.4: The ‘verify’ argument was added.

          Note: If you want to send configurations to the listener which
          don’t disable existing loggers, you will need to use a JSON
          format for the configuration, which will use *note
          dictConfig(): 11f4. for configuration.  This method allows you
          to specify ‘disable_existing_loggers’ as ‘False’ in the
          configuration you send.

 -- Function: logging.config.stopListening ()

     Stops the listening server which was created with a call to *note
     listen(): f9e.  This is typically called before calling ‘join()’ on
     the return value from ‘listen()’.


File: python.info,  Node: Security considerations,  Next: Configuration dictionary schema,  Prev: Configuration functions,  Up: logging config — Logging configuration

5.16.5.2 Security considerations
................................

The logging configuration functionality tries to offer convenience, and
in part this is done by offering the ability to convert text in
configuration files into Python objects used in logging configuration -
for example, as described in *note User-defined objects: 2eac.  However,
these same mechanisms (importing callables from user-defined modules and
calling them with parameters from the configuration) could be used to
invoke any code you like, and for this reason you should treat
configuration files from untrusted sources with 'extreme caution' and
satisfy yourself that nothing bad can happen if you load them, before
actually loading them.


File: python.info,  Node: Configuration dictionary schema,  Next: Configuration file format,  Prev: Security considerations,  Up: logging config — Logging configuration

5.16.5.3 Configuration dictionary schema
........................................

Describing a logging configuration requires listing the various objects
to create and the connections between them; for example, you may create
a handler named ‘console’ and then say that the logger named ‘startup’
will send its messages to the ‘console’ handler.  These objects aren’t
limited to those provided by the *note logging: 87. module because you
might write your own formatter or handler class.  The parameters to
these classes may also need to include external objects such as
‘sys.stderr’.  The syntax for describing these objects and connections
is defined in *note Object connections: 2eae. below.

* Menu:

* Dictionary Schema Details::
* Incremental Configuration::
* Object connections::
* User-defined objects::
* Handler configuration order::
* Access to external objects::
* Access to internal objects::
* Import resolution and custom importers::
* Configuring QueueHandler and QueueListener::


File: python.info,  Node: Dictionary Schema Details,  Next: Incremental Configuration,  Up: Configuration dictionary schema

5.16.5.4 Dictionary Schema Details
..................................

The dictionary passed to *note dictConfig(): 11f4. must contain the
following keys:

   * 'version' - to be set to an integer value representing the schema
     version.  The only valid value at present is 1, but having this key
     allows the schema to evolve while still preserving backwards
     compatibility.

All other keys are optional, but if present they will be interpreted as
described below.  In all cases below where a ‘configuring dict’ is
mentioned, it will be checked for the special ‘'()'’ key to see if a
custom instantiation is required.  If so, the mechanism described in
*note User-defined objects: 2eac. below is used to create an instance;
otherwise, the context is used to determine what to instantiate.

   * 'formatters' - the corresponding value will be a dict in which each
     key is a formatter id and each value is a dict describing how to
     configure the corresponding *note Formatter: 14e6. instance.

     The configuring dict is searched for the following optional keys
     which correspond to the arguments passed to create a *note
     Formatter: 14e6. object:

        * ‘format’

        * ‘datefmt’

        * ‘style’

        * ‘validate’ (since version >=3.8)

        * ‘defaults’ (since version >=3.12)

     An optional ‘class’ key indicates the name of the formatter’s class
     (as a dotted module and class name).  The instantiation arguments
     are as for *note Formatter: 14e6, thus this key is most useful for
     instantiating a customised subclass of ‘Formatter’.  For example,
     the alternative class might present exception tracebacks in an
     expanded or condensed format.  If your formatter requires different
     or extra configuration keys, you should use *note User-defined
     objects: 2eac.

   * 'filters' - the corresponding value will be a dict in which each
     key is a filter id and each value is a dict describing how to
     configure the corresponding Filter instance.

     The configuring dict is searched for the key ‘name’ (defaulting to
     the empty string) and this is used to construct a *note
     logging.Filter: 1240. instance.

   * 'handlers' - the corresponding value will be a dict in which each
     key is a handler id and each value is a dict describing how to
     configure the corresponding Handler instance.

     The configuring dict is searched for the following keys:

        * ‘class’ (mandatory).  This is the fully qualified name of the
          handler class.

        * ‘level’ (optional).  The level of the handler.

        * ‘formatter’ (optional).  The id of the formatter for this
          handler.

        * ‘filters’ (optional).  A list of ids of the filters for this
          handler.

          Changed in version 3.11: ‘filters’ can take filter instances
          in addition to ids.

     All 'other' keys are passed through as keyword arguments to the
     handler’s constructor.  For example, given the snippet:

          handlers:
            console:
              class : logging.StreamHandler
              formatter: brief
              level   : INFO
              filters: [allow_foo]
              stream  : ext://sys.stdout
            file:
              class : logging.handlers.RotatingFileHandler
              formatter: precise
              filename: logconfig.log
              maxBytes: 1024
              backupCount: 3

     the handler with id ‘console’ is instantiated as a *note
     logging.StreamHandler: 123d, using ‘sys.stdout’ as the underlying
     stream.  The handler with id ‘file’ is instantiated as a *note
     logging.handlers.RotatingFileHandler: 16e0. with the keyword
     arguments ‘filename='logconfig.log', maxBytes=1024, backupCount=3’.

   * 'loggers' - the corresponding value will be a dict in which each
     key is a logger name and each value is a dict describing how to
     configure the corresponding Logger instance.

     The configuring dict is searched for the following keys:

        * ‘level’ (optional).  The level of the logger.

        * ‘propagate’ (optional).  The propagation setting of the
          logger.

        * ‘filters’ (optional).  A list of ids of the filters for this
          logger.

          Changed in version 3.11: ‘filters’ can take filter instances
          in addition to ids.

        * ‘handlers’ (optional).  A list of ids of the handlers for this
          logger.

     The specified loggers will be configured according to the level,
     propagation, filters and handlers specified.

   * 'root' - this will be the configuration for the root logger.
     Processing of the configuration will be as for any logger, except
     that the ‘propagate’ setting will not be applicable.

   * 'incremental' - whether the configuration is to be interpreted as
     incremental to the existing configuration.  This value defaults to
     ‘False’, which means that the specified configuration replaces the
     existing configuration with the same semantics as used by the
     existing *note fileConfig(): b6c. API.

     If the specified value is ‘True’, the configuration is processed as
     described in the section on *note Incremental Configuration: 2eb1.

   * 'disable_existing_loggers' - whether any existing non-root loggers
     are to be disabled.  This setting mirrors the parameter of the same
     name in *note fileConfig(): b6c.  If absent, this parameter
     defaults to ‘True’.  This value is ignored if 'incremental' is
     ‘True’.


File: python.info,  Node: Incremental Configuration,  Next: Object connections,  Prev: Dictionary Schema Details,  Up: Configuration dictionary schema

5.16.5.5 Incremental Configuration
..................................

It is difficult to provide complete flexibility for incremental
configuration.  For example, because objects such as filters and
formatters are anonymous, once a configuration is set up, it is not
possible to refer to such anonymous objects when augmenting a
configuration.

Furthermore, there is not a compelling case for arbitrarily altering the
object graph of loggers, handlers, filters, formatters at run-time, once
a configuration is set up; the verbosity of loggers and handlers can be
controlled just by setting levels (and, in the case of loggers,
propagation flags).  Changing the object graph arbitrarily in a safe way
is problematic in a multi-threaded environment; while not impossible,
the benefits are not worth the complexity it adds to the implementation.

Thus, when the ‘incremental’ key of a configuration dict is present and
is ‘True’, the system will completely ignore any ‘formatters’ and
‘filters’ entries, and process only the ‘level’ settings in the
‘handlers’ entries, and the ‘level’ and ‘propagate’ settings in the
‘loggers’ and ‘root’ entries.

Using a value in the configuration dict lets configurations to be sent
over the wire as pickled dicts to a socket listener.  Thus, the logging
verbosity of a long-running application can be altered over time with no
need to stop and restart the application.


File: python.info,  Node: Object connections,  Next: User-defined objects,  Prev: Incremental Configuration,  Up: Configuration dictionary schema

5.16.5.6 Object connections
...........................

The schema describes a set of logging objects - loggers, handlers,
formatters, filters - which are connected to each other in an object
graph.  Thus, the schema needs to represent connections between the
objects.  For example, say that, once configured, a particular logger
has attached to it a particular handler.  For the purposes of this
discussion, we can say that the logger represents the source, and the
handler the destination, of a connection between the two.  Of course in
the configured objects this is represented by the logger holding a
reference to the handler.  In the configuration dict, this is done by
giving each destination object an id which identifies it unambiguously,
and then using the id in the source object’s configuration to indicate
that a connection exists between the source and the destination object
with that id.

So, for example, consider the following YAML snippet:

     formatters:
       brief:
         # configuration for formatter with id 'brief' goes here
       precise:
         # configuration for formatter with id 'precise' goes here
     handlers:
       h1: #This is an id
        # configuration of handler with id 'h1' goes here
        formatter: brief
       h2: #This is another id
        # configuration of handler with id 'h2' goes here
        formatter: precise
     loggers:
       foo.bar.baz:
         # other configuration for logger 'foo.bar.baz'
         handlers: [h1, h2]

(Note: YAML used here because it’s a little more readable than the
equivalent Python source form for the dictionary.)

The ids for loggers are the logger names which would be used
programmatically to obtain a reference to those loggers, e.g.
‘foo.bar.baz’.  The ids for Formatters and Filters can be any string
value (such as ‘brief’, ‘precise’ above) and they are transient, in that
they are only meaningful for processing the configuration dictionary and
used to determine connections between objects, and are not persisted
anywhere when the configuration call is complete.

The above snippet indicates that logger named ‘foo.bar.baz’ should have
two handlers attached to it, which are described by the handler ids ‘h1’
and ‘h2’.  The formatter for ‘h1’ is that described by id ‘brief’, and
the formatter for ‘h2’ is that described by id ‘precise’.


File: python.info,  Node: User-defined objects,  Next: Handler configuration order,  Prev: Object connections,  Up: Configuration dictionary schema

5.16.5.7 User-defined objects
.............................

The schema supports user-defined objects for handlers, filters and
formatters.  (Loggers do not need to have different types for different
instances, so there is no support in this configuration schema for
user-defined logger classes.)

Objects to be configured are described by dictionaries which detail
their configuration.  In some places, the logging system will be able to
infer from the context how an object is to be instantiated, but when a
user-defined object is to be instantiated, the system will not know how
to do this.  In order to provide complete flexibility for user-defined
object instantiation, the user needs to provide a ‘factory’ - a callable
which is called with a configuration dictionary and which returns the
instantiated object.  This is signalled by an absolute import path to
the factory being made available under the special key ‘'()'’.  Here’s a
concrete example:

     formatters:
       brief:
         format: '%(message)s'
       default:
         format: '%(asctime)s %(levelname)-8s %(name)-15s %(message)s'
         datefmt: '%Y-%m-%d %H:%M:%S'
       custom:
           (): my.package.customFormatterFactory
           bar: baz
           spam: 99.9
           answer: 42

The above YAML snippet defines three formatters.  The first, with id
‘brief’, is a standard *note logging.Formatter: 14e6. instance with the
specified format string.  The second, with id ‘default’, has a longer
format and also defines the time format explicitly, and will result in a
‘logging.Formatter’ initialized with those two format strings.  Shown in
Python source form, the ‘brief’ and ‘default’ formatters have
configuration sub-dictionaries:

     {
       'format' : '%(message)s'
     }

and:

     {
       'format' : '%(asctime)s %(levelname)-8s %(name)-15s %(message)s',
       'datefmt' : '%Y-%m-%d %H:%M:%S'
     }

respectively, and as these dictionaries do not contain the special key
‘'()'’, the instantiation is inferred from the context: as a result,
standard *note logging.Formatter: 14e6. instances are created.  The
configuration sub-dictionary for the third formatter, with id ‘custom’,
is:

     {
       '()' : 'my.package.customFormatterFactory',
       'bar' : 'baz',
       'spam' : 99.9,
       'answer' : 42
     }

and this contains the special key ‘'()'’, which means that user-defined
instantiation is wanted.  In this case, the specified factory callable
will be used.  If it is an actual callable it will be used directly -
otherwise, if you specify a string (as in the example) the actual
callable will be located using normal import mechanisms.  The callable
will be called with the 'remaining' items in the configuration
sub-dictionary as keyword arguments.  In the above example, the
formatter with id ‘custom’ will be assumed to be returned by the call:

     my.package.customFormatterFactory(bar='baz', spam=99.9, answer=42)

     Warning: The values for keys such as ‘bar’, ‘spam’ and ‘answer’ in
     the above example should not be configuration dictionaries or
     references such as ‘cfg://foo’ or ‘ext://bar’, because they will
     not be processed by the configuration machinery, but passed to the
     callable as-is.

The key ‘'()'’ has been used as the special key because it is not a
valid keyword parameter name, and so will not clash with the names of
the keyword arguments used in the call.  The ‘'()'’ also serves as a
mnemonic that the corresponding value is a callable.

Changed in version 3.11: The ‘filters’ member of ‘handlers’ and
‘loggers’ can take filter instances in addition to ids.

You can also specify a special key ‘'.'’ whose value is a mapping of
attribute names to values.  If found, the specified attributes will be
set on the user-defined object before it is returned.  Thus, with the
following configuration:

     {
       '()' : 'my.package.customFormatterFactory',
       'bar' : 'baz',
       'spam' : 99.9,
       'answer' : 42,
       '.' {
         'foo': 'bar',
         'baz': 'bozz'
       }
     }

the returned formatter will have attribute ‘foo’ set to ‘'bar'’ and
attribute ‘baz’ set to ‘'bozz'’.

     Warning: The values for attributes such as ‘foo’ and ‘baz’ in the
     above example should not be configuration dictionaries or
     references such as ‘cfg://foo’ or ‘ext://bar’, because they will
     not be processed by the configuration machinery, but set as
     attribute values as-is.


File: python.info,  Node: Handler configuration order,  Next: Access to external objects,  Prev: User-defined objects,  Up: Configuration dictionary schema

5.16.5.8 Handler configuration order
....................................

Handlers are configured in alphabetical order of their keys, and a
configured handler replaces the configuration dictionary in (a working
copy of) the ‘handlers’ dictionary in the schema.  If you use a
construct such as ‘cfg://handlers.foo’, then initially ‘handlers['foo']’
points to the configuration dictionary for the handler named ‘foo’, and
later (once that handler has been configured) it points to the
configured handler instance.  Thus, ‘cfg://handlers.foo’ could resolve
to either a dictionary or a handler instance.  In general, it is wise to
name handlers in a way such that dependent handlers are configured
'after' any handlers they depend on; that allows something like
‘cfg://handlers.foo’ to be used in configuring a handler that depends on
handler ‘foo’.  If that dependent handler were named ‘bar’, problems
would result, because the configuration of ‘bar’ would be attempted
before that of ‘foo’, and ‘foo’ would not yet have been configured.
However, if the dependent handler were named ‘foobar’, it would be
configured after ‘foo’, with the result that ‘cfg://handlers.foo’ would
resolve to configured handler ‘foo’, and not its configuration
dictionary.


File: python.info,  Node: Access to external objects,  Next: Access to internal objects,  Prev: Handler configuration order,  Up: Configuration dictionary schema

5.16.5.9 Access to external objects
...................................

There are times where a configuration needs to refer to objects external
to the configuration, for example ‘sys.stderr’.  If the configuration
dict is constructed using Python code, this is straightforward, but a
problem arises when the configuration is provided via a text file (e.g.
JSON, YAML). In a text file, there is no standard way to distinguish
‘sys.stderr’ from the literal string ‘'sys.stderr'’.  To facilitate this
distinction, the configuration system looks for certain special prefixes
in string values and treat them specially.  For example, if the literal
string ‘'ext://sys.stderr'’ is provided as a value in the configuration,
then the ‘ext://’ will be stripped off and the remainder of the value
processed using normal import mechanisms.

The handling of such prefixes is done in a way analogous to protocol
handling: there is a generic mechanism to look for prefixes which match
the regular expression ‘^(?P<prefix>[a-z]+)://(?P<suffix>.*)$’ whereby,
if the ‘prefix’ is recognised, the ‘suffix’ is processed in a
prefix-dependent manner and the result of the processing replaces the
string value.  If the prefix is not recognised, then the string value
will be left as-is.


File: python.info,  Node: Access to internal objects,  Next: Import resolution and custom importers,  Prev: Access to external objects,  Up: Configuration dictionary schema

5.16.5.10 Access to internal objects
....................................

As well as external objects, there is sometimes also a need to refer to
objects in the configuration.  This will be done implicitly by the
configuration system for things that it knows about.  For example, the
string value ‘'DEBUG'’ for a ‘level’ in a logger or handler will
automatically be converted to the value ‘logging.DEBUG’, and the
‘handlers’, ‘filters’ and ‘formatter’ entries will take an object id and
resolve to the appropriate destination object.

However, a more generic mechanism is needed for user-defined objects
which are not known to the *note logging: 87. module.  For example,
consider *note logging.handlers.MemoryHandler: 2ebb, which takes a
‘target’ argument which is another handler to delegate to.  Since the
system already knows about this class, then in the configuration, the
given ‘target’ just needs to be the object id of the relevant target
handler, and the system will resolve to the handler from the id.  If,
however, a user defines a ‘my.package.MyHandler’ which has an
‘alternate’ handler, the configuration system would not know that the
‘alternate’ referred to a handler.  To cater for this, a generic
resolution system allows the user to specify:

     handlers:
       file:
         # configuration of file handler goes here

       custom:
         (): my.package.MyHandler
         alternate: cfg://handlers.file

The literal string ‘'cfg://handlers.file'’ will be resolved in an
analogous way to strings with the ‘ext://’ prefix, but looking in the
configuration itself rather than the import namespace.  The mechanism
allows access by dot or by index, in a similar way to that provided by
‘str.format’.  Thus, given the following snippet:

     handlers:
       email:
         class: logging.handlers.SMTPHandler
         mailhost: localhost
         fromaddr: my_app@domain.tld
         toaddrs:
           - support_team@domain.tld
           - dev_team@domain.tld
         subject: Houston, we have a problem.

in the configuration, the string ‘'cfg://handlers'’ would resolve to the
dict with key ‘handlers’, the string ‘'cfg://handlers.email’ would
resolve to the dict with key ‘email’ in the ‘handlers’ dict, and so on.
The string ‘'cfg://handlers.email.toaddrs[1]’ would resolve to
‘'dev_team@domain.tld'’ and the string
‘'cfg://handlers.email.toaddrs[0]'’ would resolve to the value
‘'support_team@domain.tld'’.  The ‘subject’ value could be accessed
using either ‘'cfg://handlers.email.subject'’ or, equivalently,
‘'cfg://handlers.email[subject]'’.  The latter form only needs to be
used if the key contains spaces or non-alphanumeric characters.  Please
note that the characters ‘[’ and ‘]’ are not allowed in the keys.  If an
index value consists only of decimal digits, access will be attempted
using the corresponding integer value, falling back to the string value
if needed.

Given a string ‘cfg://handlers.myhandler.mykey.123’, this will resolve
to ‘config_dict['handlers']['myhandler']['mykey']['123']’.  If the
string is specified as ‘cfg://handlers.myhandler.mykey[123]’, the system
will attempt to retrieve the value from
‘config_dict['handlers']['myhandler']['mykey'][123]’, and fall back to
‘config_dict['handlers']['myhandler']['mykey']['123']’ if that fails.


File: python.info,  Node: Import resolution and custom importers,  Next: Configuring QueueHandler and QueueListener,  Prev: Access to internal objects,  Up: Configuration dictionary schema

5.16.5.11 Import resolution and custom importers
................................................

Import resolution, by default, uses the builtin *note __import__(): 8dd.
function to do its importing.  You may want to replace this with your
own importing mechanism: if so, you can replace the ‘importer’ attribute
of the ‘DictConfigurator’ or its superclass, the ‘BaseConfigurator’
class.  However, you need to be careful because of the way functions are
accessed from classes via descriptors.  If you are using a Python
callable to do your imports, and you want to define it at class level
rather than instance level, you need to wrap it with *note
staticmethod(): 419.  For example:

     from importlib import import_module
     from logging.config import BaseConfigurator

     BaseConfigurator.importer = staticmethod(import_module)

You don’t need to wrap with *note staticmethod(): 419. if you’re setting
the import callable on a configurator 'instance'.


File: python.info,  Node: Configuring QueueHandler and QueueListener,  Prev: Import resolution and custom importers,  Up: Configuration dictionary schema

5.16.5.12 Configuring QueueHandler and QueueListener
....................................................

If you want to configure a *note QueueHandler: 1907, noting that this is
normally used in conjunction with a *note QueueListener: e5f, you can
configure both together.  After the configuration, the ‘QueueListener’
instance will be available as the *note listener: 2ebf. attribute of the
created handler, and that in turn will be available to you using *note
getHandlerByName(): 1908. and passing the name you have used for the
‘QueueHandler’ in your configuration.  The dictionary schema for
configuring the pair is shown in the example YAML snippet below.

     handlers:
       qhand:
         class: logging.handlers.QueueHandler
         queue: my.module.queue_factory
         listener: my.package.CustomListener
         handlers:
           - hand_name_1
           - hand_name_2
           ...

The ‘queue’ and ‘listener’ keys are optional.

If the ‘queue’ key is present, the corresponding value can be one of the
following:

   * An object implementing the *note Queue.put_nowait: 2ec0. and *note
     Queue.get: 2ec1. public API. For instance, this may be an actual
     instance of *note queue.Queue: 13e1. or a subclass thereof, or a
     proxy obtained by *note
     multiprocessing.managers.SyncManager.Queue(): 2ec2.

     This is of course only possible if you are constructing or
     modifying the configuration dictionary in code.

   * A string that resolves to a callable which, when called with no
     arguments, returns the queue instance to use.  That callable could
     be a *note queue.Queue: 13e1. subclass or a function which returns
     a suitable queue instance, such as ‘my.module.queue_factory()’.

   * A dict with a ‘'()'’ key which is constructed in the usual way as
     discussed in *note User-defined objects: 2eac.  The result of this
     construction should be a *note queue.Queue: 13e1. instance.

If the ‘queue’ key is absent, a standard unbounded *note queue.Queue:
13e1. instance is created and used.

If the ‘listener’ key is present, the corresponding value can be one of
the following:

   * A subclass of *note logging.handlers.QueueListener: e5f.  This is
     of course only possible if you are constructing or modifying the
     configuration dictionary in code.

   * A string which resolves to a class which is a subclass of
     ‘QueueListener’, such as ‘'my.package.CustomListener'’.

   * A dict with a ‘'()'’ key which is constructed in the usual way as
     discussed in *note User-defined objects: 2eac.  The result of this
     construction should be a callable with the same signature as the
     ‘QueueListener’ initializer.

If the ‘listener’ key is absent, *note logging.handlers.QueueListener:
e5f. is used.

The values under the ‘handlers’ key are the names of other handlers in
the configuration (not shown in the above snippet) which will be passed
to the queue listener.

Any custom queue handler and listener classes will need to be defined
with the same initialization signatures as *note QueueHandler: 1907. and
*note QueueListener: e5f.

Added in version 3.12.


File: python.info,  Node: Configuration file format,  Prev: Configuration dictionary schema,  Up: logging config — Logging configuration

5.16.5.13 Configuration file format
...................................

The configuration file format understood by *note fileConfig(): b6c. is
based on *note configparser: 22. functionality.  The file must contain
sections called ‘[loggers]’, ‘[handlers]’ and ‘[formatters]’ which
identify by name the entities of each type which are defined in the
file.  For each such entity, there is a separate section which
identifies how that entity is configured.  Thus, for a logger named
‘log01’ in the ‘[loggers]’ section, the relevant configuration details
are held in a section ‘[logger_log01]’.  Similarly, a handler called
‘hand01’ in the ‘[handlers]’ section will have its configuration held in
a section called ‘[handler_hand01]’, while a formatter called ‘form01’
in the ‘[formatters]’ section will have its configuration specified in a
section called ‘[formatter_form01]’.  The root logger configuration must
be specified in a section called ‘[logger_root]’.

     Note: The *note fileConfig(): b6c. API is older than the *note
     dictConfig(): 11f4. API and does not provide functionality to cover
     certain aspects of logging.  For example, you cannot configure
     *note Filter: 1240. objects, which provide for filtering of
     messages beyond simple integer levels, using ‘fileConfig()’.  If
     you need to have instances of ‘Filter’ in your logging
     configuration, you will need to use ‘dictConfig()’.  Note that
     future enhancements to configuration functionality will be added to
     ‘dictConfig()’, so it’s worth considering transitioning to this
     newer API when it’s convenient to do so.

Examples of these sections in the file are given below.

     [loggers]
     keys=root,log02,log03,log04,log05,log06,log07

     [handlers]
     keys=hand01,hand02,hand03,hand04,hand05,hand06,hand07,hand08,hand09

     [formatters]
     keys=form01,form02,form03,form04,form05,form06,form07,form08,form09

The root logger must specify a level and a list of handlers.  An example
of a root logger section is given below.

     [logger_root]
     level=NOTSET
     handlers=hand01

The ‘level’ entry can be one of ‘DEBUG, INFO, WARNING, ERROR, CRITICAL’
or ‘NOTSET’.  For the root logger only, ‘NOTSET’ means that all messages
will be logged.  Level values are *note evaluated: 2325. in the context
of the ‘logging’ package’s namespace.

The ‘handlers’ entry is a comma-separated list of handler names, which
must appear in the ‘[handlers]’ section.  These names must appear in the
‘[handlers]’ section and have corresponding sections in the
configuration file.

For loggers other than the root logger, some additional information is
required.  This is illustrated by the following example.

     [logger_parser]
     level=DEBUG
     handlers=hand01
     propagate=1
     qualname=compiler.parser

The ‘level’ and ‘handlers’ entries are interpreted as for the root
logger, except that if a non-root logger’s level is specified as
‘NOTSET’, the system consults loggers higher up the hierarchy to
determine the effective level of the logger.  The ‘propagate’ entry is
set to 1 to indicate that messages must propagate to handlers higher up
the logger hierarchy from this logger, or 0 to indicate that messages
are 'not' propagated to handlers up the hierarchy.  The ‘qualname’ entry
is the hierarchical channel name of the logger, that is to say the name
used by the application to get the logger.

Sections which specify handler configuration are exemplified by the
following.

     [handler_hand01]
     class=StreamHandler
     level=NOTSET
     formatter=form01
     args=(sys.stdout,)

The ‘class’ entry indicates the handler’s class (as determined by *note
eval(): 180. in the ‘logging’ package’s namespace).  The ‘level’ is
interpreted as for loggers, and ‘NOTSET’ is taken to mean ‘log
everything’.

The ‘formatter’ entry indicates the key name of the formatter for this
handler.  If blank, a default formatter (‘logging._defaultFormatter’) is
used.  If a name is specified, it must appear in the ‘[formatters]’
section and have a corresponding section in the configuration file.

The ‘args’ entry, when *note evaluated: 2325. in the context of the
‘logging’ package’s namespace, is the list of arguments to the
constructor for the handler class.  Refer to the constructors for the
relevant handlers, or to the examples below, to see how typical entries
are constructed.  If not provided, it defaults to ‘()’.

The optional ‘kwargs’ entry, when *note evaluated: 2325. in the context
of the ‘logging’ package’s namespace, is the keyword argument dict to
the constructor for the handler class.  If not provided, it defaults to
‘{}’.

     [handler_hand02]
     class=FileHandler
     level=DEBUG
     formatter=form02
     args=('python.log', 'w')

     [handler_hand03]
     class=handlers.SocketHandler
     level=INFO
     formatter=form03
     args=('localhost', handlers.DEFAULT_TCP_LOGGING_PORT)

     [handler_hand04]
     class=handlers.DatagramHandler
     level=WARN
     formatter=form04
     args=('localhost', handlers.DEFAULT_UDP_LOGGING_PORT)

     [handler_hand05]
     class=handlers.SysLogHandler
     level=ERROR
     formatter=form05
     args=(('localhost', handlers.SYSLOG_UDP_PORT), handlers.SysLogHandler.LOG_USER)

     [handler_hand06]
     class=handlers.NTEventLogHandler
     level=CRITICAL
     formatter=form06
     args=('Python Application', '', 'Application')

     [handler_hand07]
     class=handlers.SMTPHandler
     level=WARN
     formatter=form07
     args=('localhost', 'from@abc', ['user1@abc', 'user2@xyz'], 'Logger Subject')
     kwargs={'timeout': 10.0}

     [handler_hand08]
     class=handlers.MemoryHandler
     level=NOTSET
     formatter=form08
     target=
     args=(10, ERROR)

     [handler_hand09]
     class=handlers.HTTPHandler
     level=NOTSET
     formatter=form09
     args=('localhost:9022', '/log', 'GET')
     kwargs={'secure': True}

Sections which specify formatter configuration are typified by the
following.

     [formatter_form01]
     format=F1 %(asctime)s %(levelname)s %(message)s %(customfield)s
     datefmt=
     style=%
     validate=True
     defaults={'customfield': 'defaultvalue'}
     class=logging.Formatter

The arguments for the formatter configuration are the same as the keys
in the dictionary schema *note formatters section: 2eb0.

The ‘defaults’ entry, when *note evaluated: 2325. in the context of the
‘logging’ package’s namespace, is a dictionary of default values for
custom formatting fields.  If not provided, it defaults to ‘None’.

     Note: Due to the use of *note eval(): 180. as described above,
     there are potential security risks which result from using the
     *note listen(): f9e. to send and receive configurations via
     sockets.  The risks are limited to where multiple users with no
     mutual trust run code on the same machine; see the ‘listen()’
     documentation for more information.

See also
........

Module *note logging: 87.

     API reference for the logging module.

Module *note logging.handlers: 89.

     Useful handlers included with the logging module.


File: python.info,  Node: logging handlers — Logging handlers,  Next: platform — Access to underlying platform’s identifying data,  Prev: logging config — Logging configuration,  Up: Generic Operating System Services

5.16.6 ‘logging.handlers’ — Logging handlers
--------------------------------------------

'Source code:' Lib/logging/handlers.py(1)

Important
.........

This page contains only reference information.  For tutorials, please
see

   * *note Basic Tutorial: 123a.

   * *note Advanced Tutorial: 123b.

   * *note Logging Cookbook: 123c.

__________________________________________________________________

The following useful handlers are provided in the package.  Note that
three of the handlers (*note StreamHandler: 123d, *note FileHandler:
19f9. and *note NullHandler: 12cb.) are actually defined in the *note
logging: 87. module itself, but have been documented here along with the
other handlers.

* Menu:

* StreamHandler::
* FileHandler::
* NullHandler::
* WatchedFileHandler::
* BaseRotatingHandler::
* RotatingFileHandler::
* TimedRotatingFileHandler::
* SocketHandler::
* DatagramHandler::
* SysLogHandler::
* NTEventLogHandler::
* SMTPHandler::
* MemoryHandler::
* HTTPHandler::
* QueueHandler::
* QueueListener::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/logging/handlers.py


File: python.info,  Node: StreamHandler,  Next: FileHandler,  Up: logging handlers — Logging handlers

5.16.6.1 StreamHandler
......................

The *note StreamHandler: 123d. class, located in the core *note logging:
87. package, sends logging output to streams such as 'sys.stdout',
'sys.stderr' or any file-like object (or, more precisely, any object
which supports ‘write()’ and ‘flush()’ methods).

 -- Class: logging.StreamHandler (stream=None)

     Returns a new instance of the ‘StreamHandler’ class.  If 'stream'
     is specified, the instance will use it for logging output;
     otherwise, 'sys.stderr' will be used.

      -- Method: emit (record)

          If a formatter is specified, it is used to format the record.
          The record is then written to the stream followed by *note
          terminator: 2eca.  If exception information is present, it is
          formatted using *note traceback.print_exception(): 855. and
          appended to the stream.

      -- Method: flush ()

          Flushes the stream by calling its ‘flush()’ method.  Note that
          the ‘close()’ method is inherited from *note Handler: 14e5.
          and so does no output, so an explicit ‘flush()’ call may be
          needed at times.

      -- Method: setStream (stream)

          Sets the instance’s stream to the specified value, if it is
          different.  The old stream is flushed before the new stream is
          set.


          Parameters: ‘stream’ – The stream that the handler should use.


          Returns: the old stream, if the stream was changed, or ‘None’
          if it wasn’t.

          Added in version 3.7.

      -- Attribute: terminator

          String used as the terminator when writing a formatted record
          to a stream.  Default value is ‘'\n'’.

          If you don’t want a newline termination, you can set the
          handler instance’s ‘terminator’ attribute to the empty string.

          In earlier versions, the terminator was hardcoded as ‘'\n'’.

          Added in version 3.2.


File: python.info,  Node: FileHandler,  Next: NullHandler,  Prev: StreamHandler,  Up: logging handlers — Logging handlers

5.16.6.2 FileHandler
....................

The *note FileHandler: 19f9. class, located in the core *note logging:
87. package, sends logging output to a disk file.  It inherits the
output functionality from *note StreamHandler: 123d.

 -- Class: logging.FileHandler (filename, mode='a', encoding=None,
          delay=False, errors=None)

     Returns a new instance of the ‘FileHandler’ class.  The specified
     file is opened and used as the stream for logging.  If 'mode' is
     not specified, ‘'a'’ is used.  If 'encoding' is not ‘None’, it is
     used to open the file with that encoding.  If 'delay' is true, then
     file opening is deferred until the first call to *note emit():
     2ece.  By default, the file grows indefinitely.  If 'errors' is
     specified, it’s used to determine how encoding errors are handled.

     Changed in version 3.6: As well as string values, *note Path: 229.
     objects are also accepted for the 'filename' argument.

     Changed in version 3.9: The 'errors' parameter was added.

      -- Method: close ()

          Closes the file.

      -- Method: emit (record)

          Outputs the record to the file.

          Note that if the file was closed due to logging shutdown at
          exit and the file mode is ‘w’, the record will not be emitted
          (see bpo-42378(1)).

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=42378


File: python.info,  Node: NullHandler,  Next: WatchedFileHandler,  Prev: FileHandler,  Up: logging handlers — Logging handlers

5.16.6.3 NullHandler
....................

Added in version 3.1.

The *note NullHandler: 12cb. class, located in the core *note logging:
87. package, does not do any formatting or output.  It is essentially a
‘no-op’ handler for use by library developers.

 -- Class: logging.NullHandler

     Returns a new instance of the ‘NullHandler’ class.

      -- Method: emit (record)

          This method does nothing.

      -- Method: handle (record)

          This method does nothing.

      -- Method: createLock ()

          This method returns ‘None’ for the lock, since there is no
          underlying I/O to which access needs to be serialized.

See *note Configuring Logging for a Library: 2ed5. for more information
on how to use *note NullHandler: 12cb.


File: python.info,  Node: WatchedFileHandler,  Next: BaseRotatingHandler,  Prev: NullHandler,  Up: logging handlers — Logging handlers

5.16.6.4 WatchedFileHandler
...........................

The *note WatchedFileHandler: 2ed8. class, located in the
‘logging.handlers’ module, is a ‘FileHandler’ which watches the file it
is logging to.  If the file changes, it is closed and reopened using the
file name.

A file change can happen because of usage of programs such as
'newsyslog' and 'logrotate' which perform log file rotation.  This
handler, intended for use under Unix/Linux, watches the file to see if
it has changed since the last emit.  (A file is deemed to have changed
if its device or inode have changed.)  If the file has changed, the old
file stream is closed, and the file opened to get a new stream.

This handler is not appropriate for use under Windows, because under
Windows open log files cannot be moved or renamed - logging opens the
files with exclusive locks - and so there is no need for such a handler.
Furthermore, 'ST_INO' is not supported under Windows; *note stat(): 4a3.
always returns zero for this value.

 -- Class: logging.handlers.WatchedFileHandler (filename, mode='a',
          encoding=None, delay=False, errors=None)

     Returns a new instance of the ‘WatchedFileHandler’ class.  The
     specified file is opened and used as the stream for logging.  If
     'mode' is not specified, ‘'a'’ is used.  If 'encoding' is not
     ‘None’, it is used to open the file with that encoding.  If 'delay'
     is true, then file opening is deferred until the first call to
     *note emit(): 2ed9.  By default, the file grows indefinitely.  If
     'errors' is provided, it determines how encoding errors are
     handled.

     Changed in version 3.6: As well as string values, *note Path: 229.
     objects are also accepted for the 'filename' argument.

     Changed in version 3.9: The 'errors' parameter was added.

      -- Method: reopenIfNeeded ()

          Checks to see if the file has changed.  If it has, the
          existing stream is flushed and closed and the file opened
          again, typically as a precursor to outputting the record to
          the file.

          Added in version 3.6.

      -- Method: emit (record)

          Outputs the record to the file, but first calls *note
          reopenIfNeeded(): cdc. to reopen the file if it has changed.


File: python.info,  Node: BaseRotatingHandler,  Next: RotatingFileHandler,  Prev: WatchedFileHandler,  Up: logging handlers — Logging handlers

5.16.6.5 BaseRotatingHandler
............................

The *note BaseRotatingHandler: 2edc. class, located in the
‘logging.handlers’ module, is the base class for the rotating file
handlers, *note RotatingFileHandler: 16e0. and *note
TimedRotatingFileHandler: f9a.  You should not need to instantiate this
class, but it has attributes and methods you may need to override.

 -- Class: logging.handlers.BaseRotatingHandler (filename, mode,
          encoding=None, delay=False, errors=None)

     The parameters are as for ‘FileHandler’.  The attributes are:

      -- Attribute: namer

          If this attribute is set to a callable, the *note
          rotation_filename(): 2ede. method delegates to this callable.
          The parameters passed to the callable are those passed to
          ‘rotation_filename()’.

               Note: The namer function is called quite a few times
               during rollover, so it should be as simple and as fast as
               possible.  It should also return the same output every
               time for a given input, otherwise the rollover behaviour
               may not work as expected.

               It’s also worth noting that care should be taken when
               using a namer to preserve certain attributes in the
               filename which are used during rotation.  For example,
               *note RotatingFileHandler: 16e0. expects to have a set of
               log files whose names contain successive integers, so
               that rotation works as expected, and *note
               TimedRotatingFileHandler: f9a. deletes old log files
               (based on the ‘backupCount’ parameter passed to the
               handler’s initializer) by determining the oldest files to
               delete.  For this to happen, the filenames should be
               sortable using the date/time portion of the filename, and
               a namer needs to respect this.  (If a namer is wanted
               that doesn’t respect this scheme, it will need to be used
               in a subclass of ‘TimedRotatingFileHandler’ which
               overrides the *note getFilesToDelete(): 2edf. method to
               fit in with the custom naming scheme.)

          Added in version 3.3.

      -- Attribute: rotator

          If this attribute is set to a callable, the *note rotate():
          2ee1. method delegates to this callable.  The parameters
          passed to the callable are those passed to ‘rotate()’.

          Added in version 3.3.

      -- Method: rotation_filename (default_name)

          Modify the filename of a log file when rotating.

          This is provided so that a custom filename can be provided.

          The default implementation calls the ‘namer’ attribute of the
          handler, if it’s callable, passing the default name to it.  If
          the attribute isn’t callable (the default is ‘None’), the name
          is returned unchanged.


          Parameters: ‘default_name’ – The default name for the log
          file.

          Added in version 3.3.

      -- Method: rotate (source, dest)

          When rotating, rotate the current log.

          The default implementation calls the ‘rotator’ attribute of
          the handler, if it’s callable, passing the source and dest
          arguments to it.  If the attribute isn’t callable (the default
          is ‘None’), the source is simply renamed to the destination.


          Parameters:

             * ‘source’ – The source filename.  This is normally the
               base filename, e.g.  ‘test.log’.

             * ‘dest’ – The destination filename.  This is normally what
               the source is rotated to, e.g.  ‘test.log.1’.

          Added in version 3.3.

The reason the attributes exist is to save you having to subclass - you
can use the same callables for instances of *note RotatingFileHandler:
16e0. and *note TimedRotatingFileHandler: f9a.  If either the namer or
rotator callable raises an exception, this will be handled in the same
way as any other exception during an ‘emit()’ call, i.e.  via the
‘handleError()’ method of the handler.

If you need to make more significant changes to rotation processing, you
can override the methods.

For an example, see *note Using a rotator and namer to customize log
rotation processing: 2ee2.


File: python.info,  Node: RotatingFileHandler,  Next: TimedRotatingFileHandler,  Prev: BaseRotatingHandler,  Up: logging handlers — Logging handlers

5.16.6.6 RotatingFileHandler
............................

The *note RotatingFileHandler: 16e0. class, located in the
‘logging.handlers’ module, supports rotation of disk log files.

 -- Class: logging.handlers.RotatingFileHandler (filename, mode='a',
          maxBytes=0, backupCount=0, encoding=None, delay=False,
          errors=None)

     Returns a new instance of the ‘RotatingFileHandler’ class.  The
     specified file is opened and used as the stream for logging.  If
     'mode' is not specified, ‘'a'’ is used.  If 'encoding' is not
     ‘None’, it is used to open the file with that encoding.  If 'delay'
     is true, then file opening is deferred until the first call to
     *note emit(): 2ee5.  By default, the file grows indefinitely.  If
     'errors' is provided, it determines how encoding errors are
     handled.

     You can use the 'maxBytes' and 'backupCount' values to allow the
     file to 'rollover' at a predetermined size.  When the size is about
     to be exceeded, the file is closed and a new file is silently
     opened for output.  Rollover occurs whenever the current log file
     is nearly 'maxBytes' in length; but if either of 'maxBytes' or
     'backupCount' is zero, rollover never occurs, so you generally want
     to set 'backupCount' to at least 1, and have a non-zero 'maxBytes'.
     When 'backupCount' is non-zero, the system will save old log files
     by appending the extensions ‘.1’, ‘.2’ etc., to the filename.  For
     example, with a 'backupCount' of 5 and a base file name of
     ‘app.log’, you would get ‘app.log’, ‘app.log.1’, ‘app.log.2’, up to
     ‘app.log.5’.  The file being written to is always ‘app.log’.  When
     this file is filled, it is closed and renamed to ‘app.log.1’, and
     if files ‘app.log.1’, ‘app.log.2’, etc.  exist, then they are
     renamed to ‘app.log.2’, ‘app.log.3’ etc.  respectively.

     Changed in version 3.6: As well as string values, *note Path: 229.
     objects are also accepted for the 'filename' argument.

     Changed in version 3.9: The 'errors' parameter was added.

      -- Method: doRollover ()

          Does a rollover, as described above.

      -- Method: emit (record)

          Outputs the record to the file, catering for rollover as
          described previously.

      -- Method: shouldRollover (record)

          See if the supplied record would cause the file to exceed the
          configured size limit.


File: python.info,  Node: TimedRotatingFileHandler,  Next: SocketHandler,  Prev: RotatingFileHandler,  Up: logging handlers — Logging handlers

5.16.6.7 TimedRotatingFileHandler
.................................

The *note TimedRotatingFileHandler: f9a. class, located in the
‘logging.handlers’ module, supports rotation of disk log files at
certain timed intervals.

 -- Class: logging.handlers.TimedRotatingFileHandler (filename,
          when='h', interval=1, backupCount=0, encoding=None,
          delay=False, utc=False, atTime=None, errors=None)

     Returns a new instance of the ‘TimedRotatingFileHandler’ class.
     The specified file is opened and used as the stream for logging.
     On rotating it also sets the filename suffix.  Rotating happens
     based on the product of 'when' and 'interval'.

     You can use the 'when' to specify the type of 'interval'.  The list
     of possible values is below.  Note that they are not case
     sensitive.

     Value                Type of interval                 If/how 'atTime' is used
                                                           
     ------------------------------------------------------------------------------------
                                                           
     ‘'S'’                Seconds                          Ignored
                                                           
                                                           
     ‘'M'’                Minutes                          Ignored
                                                           
                                                           
     ‘'H'’                Hours                            Ignored
                                                           
                                                           
     ‘'D'’                Days                             Ignored
                                                           
                                                           
     ‘'W0'-'W6'’          Weekday (0=Monday)               Used to compute initial
                                                           rollover time
                                                           
                                                           
     ‘'midnight'’         Roll over at midnight, if        Used to compute initial
                          'atTime' not specified, else     rollover time
                          at time 'atTime'                 
                          

     When using weekday-based rotation, specify ‘W0’ for Monday, ‘W1’
     for Tuesday, and so on up to ‘W6’ for Sunday.  In this case, the
     value passed for 'interval' isn’t used.

     The system will save old log files by appending extensions to the
     filename.  The extensions are date-and-time based, using the
     strftime format ‘%Y-%m-%d_%H-%M-%S’ or a leading portion thereof,
     depending on the rollover interval.

     When computing the next rollover time for the first time (when the
     handler is created), the last modification time of an existing log
     file, or else the current time, is used to compute when the next
     rotation will occur.

     If the 'utc' argument is true, times in UTC will be used; otherwise
     local time is used.

     If 'backupCount' is nonzero, at most 'backupCount' files will be
     kept, and if more would be created when rollover occurs, the oldest
     one is deleted.  The deletion logic uses the interval to determine
     which files to delete, so changing the interval may leave old files
     lying around.

     If 'delay' is true, then file opening is deferred until the first
     call to *note emit(): 2eea.

     If 'atTime' is not ‘None’, it must be a ‘datetime.time’ instance
     which specifies the time of day when rollover occurs, for the cases
     where rollover is set to happen “at midnight” or “on a particular
     weekday”.  Note that in these cases, the 'atTime' value is
     effectively used to compute the 'initial' rollover, and subsequent
     rollovers would be calculated via the normal interval calculation.

     If 'errors' is specified, it’s used to determine how encoding
     errors are handled.

          Note: Calculation of the initial rollover time is done when
          the handler is initialised.  Calculation of subsequent
          rollover times is done only when rollover occurs, and rollover
          occurs only when emitting output.  If this is not kept in
          mind, it might lead to some confusion.  For example, if an
          interval of “every minute” is set, that does not mean you will
          always see log files with times (in the filename) separated by
          a minute; if, during application execution, logging output is
          generated more frequently than once a minute, 'then' you can
          expect to see log files with times separated by a minute.  If,
          on the other hand, logging messages are only output once every
          five minutes (say), then there will be gaps in the file times
          corresponding to the minutes where no output (and hence no
          rollover) occurred.

     Changed in version 3.4: 'atTime' parameter was added.

     Changed in version 3.6: As well as string values, *note Path: 229.
     objects are also accepted for the 'filename' argument.

     Changed in version 3.9: The 'errors' parameter was added.

      -- Method: doRollover ()

          Does a rollover, as described above.

      -- Method: emit (record)

          Outputs the record to the file, catering for rollover as
          described above.

      -- Method: getFilesToDelete ()

          Returns a list of filenames which should be deleted as part of
          rollover.  These are the absolute paths of the oldest backup
          log files written by the handler.

      -- Method: shouldRollover (record)

          See if enough time has passed for a rollover to occur and if
          it has, compute the next rollover time.


File: python.info,  Node: SocketHandler,  Next: DatagramHandler,  Prev: TimedRotatingFileHandler,  Up: logging handlers — Logging handlers

5.16.6.8 SocketHandler
......................

The *note SocketHandler: f9b. class, located in the ‘logging.handlers’
module, sends logging output to a network socket.  The base class uses a
TCP socket.

 -- Class: logging.handlers.SocketHandler (host, port)

     Returns a new instance of the ‘SocketHandler’ class intended to
     communicate with a remote machine whose address is given by 'host'
     and 'port'.

     Changed in version 3.4: If ‘port’ is specified as ‘None’, a Unix
     domain socket is created using the value in ‘host’ - otherwise, a
     TCP socket is created.

      -- Method: close ()

          Closes the socket.

      -- Method: emit ()

          Pickles the record’s attribute dictionary and writes it to the
          socket in binary format.  If there is an error with the
          socket, silently drops the packet.  If the connection was
          previously lost, re-establishes the connection.  To unpickle
          the record at the receiving end into a *note LogRecord: 1021,
          use the *note makeLogRecord(): 2e87. function.

      -- Method: handleError ()

          Handles an error which has occurred during *note emit(): 2ef0.
          The most likely cause is a lost connection.  Closes the socket
          so that we can retry on the next event.

      -- Method: makeSocket ()

          This is a factory method which allows subclasses to define the
          precise type of socket they want.  The default implementation
          creates a TCP socket (*note socket.SOCK_STREAM: 133c.).

      -- Method: makePickle (record)

          Pickles the record’s attribute dictionary in binary format
          with a length prefix, and returns it ready for transmission
          across the socket.  The details of this operation are
          equivalent to:

               data = pickle.dumps(record_attr_dict, 1)
               datalen = struct.pack('>L', len(data))
               return datalen + data

          Note that pickles aren’t completely secure.  If you are
          concerned about security, you may want to override this method
          to implement a more secure mechanism.  For example, you can
          sign pickles using HMAC and then verify them on the receiving
          end, or alternatively you can disable unpickling of global
          objects on the receiving end.

      -- Method: send (packet)

          Send a pickled byte-string 'packet' to the socket.  The format
          of the sent byte-string is as described in the documentation
          for *note makePickle(): 2ef3.

          This function allows for partial sends, which can happen when
          the network is busy.

      -- Method: createSocket ()

          Tries to create a socket; on failure, uses an exponential
          back-off algorithm.  On initial failure, the handler will drop
          the message it was trying to send.  When subsequent messages
          are handled by the same instance, it will not try connecting
          until some time has passed.  The default parameters are such
          that the initial delay is one second, and if after that delay
          the connection still can’t be made, the handler will double
          the delay each time up to a maximum of 30 seconds.

          This behaviour is controlled by the following handler
          attributes:

             * ‘retryStart’ (initial delay, defaulting to 1.0 seconds).

             * ‘retryFactor’ (multiplier, defaulting to 2.0).

             * ‘retryMax’ (maximum delay, defaulting to 30.0 seconds).

          This means that if the remote listener starts up 'after' the
          handler has been used, you could lose messages (since the
          handler won’t even attempt a connection until the delay has
          elapsed, but just silently drop messages during the delay
          period).


File: python.info,  Node: DatagramHandler,  Next: SysLogHandler,  Prev: SocketHandler,  Up: logging handlers — Logging handlers

5.16.6.9 DatagramHandler
........................

The *note DatagramHandler: f9c. class, located in the ‘logging.handlers’
module, inherits from *note SocketHandler: f9b. to support sending
logging messages over UDP sockets.

 -- Class: logging.handlers.DatagramHandler (host, port)

     Returns a new instance of the ‘DatagramHandler’ class intended to
     communicate with a remote machine whose address is given by 'host'
     and 'port'.

          Note: As UDP is not a streaming protocol, there is no
          persistent connection between an instance of this handler and
          'host'.  For this reason, when using a network socket, a DNS
          lookup might have to be made each time an event is logged,
          which can introduce some latency into the system.  If this
          affects you, you can do a lookup yourself and initialize this
          handler using the looked-up IP address rather than the
          hostname.

     Changed in version 3.4: If ‘port’ is specified as ‘None’, a Unix
     domain socket is created using the value in ‘host’ - otherwise, a
     UDP socket is created.

      -- Method: emit ()

          Pickles the record’s attribute dictionary and writes it to the
          socket in binary format.  If there is an error with the
          socket, silently drops the packet.  To unpickle the record at
          the receiving end into a *note LogRecord: 1021, use the *note
          makeLogRecord(): 2e87. function.

      -- Method: makeSocket ()

          The factory method of *note SocketHandler: f9b. is here
          overridden to create a UDP socket (*note socket.SOCK_DGRAM:
          133b.).

      -- Method: send (s)

          Send a pickled byte-string to a socket.  The format of the
          sent byte-string is as described in the documentation for
          *note SocketHandler.makePickle(): 2ef3.


File: python.info,  Node: SysLogHandler,  Next: NTEventLogHandler,  Prev: DatagramHandler,  Up: logging handlers — Logging handlers

5.16.6.10 SysLogHandler
.......................

The *note SysLogHandler: 65f. class, located in the ‘logging.handlers’
module, supports sending logging messages to a remote or local Unix
syslog.

 -- Class: logging.handlers.SysLogHandler (address=('localhost',
          SYSLOG_UDP_PORT), facility=LOG_USER,
          socktype=socket.SOCK_DGRAM)

     Returns a new instance of the ‘SysLogHandler’ class intended to
     communicate with a remote Unix machine whose address is given by
     'address' in the form of a ‘(host, port)’ tuple.  If 'address' is
     not specified, ‘('localhost', 514)’ is used.  The address is used
     to open a socket.  An alternative to providing a ‘(host, port)’
     tuple is providing an address as a string, for example ‘/dev/log’.
     In this case, a Unix domain socket is used to send the message to
     the syslog.  If 'facility' is not specified, ‘LOG_USER’ is used.
     The type of socket opened depends on the 'socktype' argument, which
     defaults to *note socket.SOCK_DGRAM: 133b. and thus opens a UDP
     socket.  To open a TCP socket (for use with the newer syslog
     daemons such as rsyslog), specify a value of *note
     socket.SOCK_STREAM: 133c.

     Note that if your server is not listening on UDP port 514,
     ‘SysLogHandler’ may appear not to work.  In that case, check what
     address you should be using for a domain socket - it’s system
     dependent.  For example, on Linux it’s usually ‘/dev/log’ but on
     OS/X it’s ‘/var/run/syslog’.  You’ll need to check your platform
     and use the appropriate address (you may need to do this check at
     runtime if your application needs to run on several platforms).  On
     Windows, you pretty much have to use the UDP option.

          Note: On macOS 12.x (Monterey), Apple has changed the
          behaviour of their syslog daemon - it no longer listens on a
          domain socket.  Therefore, you cannot expect ‘SysLogHandler’
          to work on this system.

          See gh-91070(1) for more information.

     Changed in version 3.2: 'socktype' was added.

      -- Method: close ()

          Closes the socket to the remote host.

      -- Method: createSocket ()

          Tries to create a socket and, if it’s not a datagram socket,
          connect it to the other end.  This method is called during
          handler initialization, but it’s not regarded as an error if
          the other end isn’t listening at this point - the method will
          be called again when emitting an event, if there is no socket
          at that point.

          Added in version 3.11.

      -- Method: emit (record)

          The record is formatted, and then sent to the syslog server.
          If exception information is present, it is 'not' sent to the
          server.

          Changed in version 3.2.1: (See: bpo-12168(2).)  In earlier
          versions, the message sent to the syslog daemons was always
          terminated with a NUL byte, because early versions of these
          daemons expected a NUL terminated message - even though it’s
          not in the relevant specification ( RFC 5424(3)).  More recent
          versions of these daemons don’t expect the NUL byte but strip
          it off if it’s there, and even more recent daemons (which
          adhere more closely to RFC 5424) pass the NUL byte on as part
          of the message.

          To enable easier handling of syslog messages in the face of
          all these differing daemon behaviours, the appending of the
          NUL byte has been made configurable, through the use of a
          class-level attribute, ‘append_nul’.  This defaults to ‘True’
          (preserving the existing behaviour) but can be set to ‘False’
          on a ‘SysLogHandler’ instance in order for that instance to
          'not' append the NUL terminator.

          Changed in version 3.3: (See: bpo-12419(4).)  In earlier
          versions, there was no facility for an “ident” or “tag” prefix
          to identify the source of the message.  This can now be
          specified using a class-level attribute, defaulting to ‘""’ to
          preserve existing behaviour, but which can be overridden on a
          ‘SysLogHandler’ instance in order for that instance to prepend
          the ident to every message handled.  Note that the provided
          ident must be text, not bytes, and is prepended to the message
          exactly as is.

      -- Method: encodePriority (facility, priority)

          Encodes the facility and priority into an integer.  You can
          pass in strings or integers - if strings are passed, internal
          mapping dictionaries are used to convert them to integers.

          The symbolic ‘LOG_’ values are defined in ‘SysLogHandler’ and
          mirror the values defined in the ‘sys/syslog.h’ header file.

          'Priorities'

          Name (string)                  Symbolic value
                                         
          ---------------------------------------------------
                                         
          ‘alert’                        LOG_ALERT
                                         
                                         
          ‘crit’ or ‘critical’           LOG_CRIT
                                         
                                         
          ‘debug’                        LOG_DEBUG
                                         
                                         
          ‘emerg’ or ‘panic’             LOG_EMERG
                                         
                                         
          ‘err’ or ‘error’               LOG_ERR
                                         
                                         
          ‘info’                         LOG_INFO
                                         
                                         
          ‘notice’                       LOG_NOTICE
                                         
                                         
          ‘warn’ or ‘warning’            LOG_WARNING
                                         

          'Facilities'

          Name (string)       Symbolic value
                              
          ----------------------------------------
                              
          ‘auth’              LOG_AUTH
                              
                              
          ‘authpriv’          LOG_AUTHPRIV
                              
                              
          ‘cron’              LOG_CRON
                              
                              
          ‘daemon’            LOG_DAEMON
                              
                              
          ‘ftp’               LOG_FTP
                              
                              
          ‘kern’              LOG_KERN
                              
                              
          ‘lpr’               LOG_LPR
                              
                              
          ‘mail’              LOG_MAIL
                              
                              
          ‘news’              LOG_NEWS
                              
                              
          ‘syslog’            LOG_SYSLOG
                              
                              
          ‘user’              LOG_USER
                              
                              
          ‘uucp’              LOG_UUCP
                              
                              
          ‘local0’            LOG_LOCAL0
                              
                              
          ‘local1’            LOG_LOCAL1
                              
                              
          ‘local2’            LOG_LOCAL2
                              
                              
          ‘local3’            LOG_LOCAL3
                              
                              
          ‘local4’            LOG_LOCAL4
                              
                              
          ‘local5’            LOG_LOCAL5
                              
                              
          ‘local6’            LOG_LOCAL6
                              
                              
          ‘local7’            LOG_LOCAL7
                              

      -- Method: mapPriority (levelname)

          Maps a logging level name to a syslog priority name.  You may
          need to override this if you are using custom levels, or if
          the default algorithm is not suitable for your needs.  The
          default algorithm maps ‘DEBUG’, ‘INFO’, ‘WARNING’, ‘ERROR’ and
          ‘CRITICAL’ to the equivalent syslog names, and all other level
          names to ‘warning’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/91070

   (2) https://bugs.python.org/issue?@action=redirect&bpo=12168

   (3) https://datatracker.ietf.org/doc/html/rfc5424.html

   (4) https://bugs.python.org/issue?@action=redirect&bpo=12419


File: python.info,  Node: NTEventLogHandler,  Next: SMTPHandler,  Prev: SysLogHandler,  Up: logging handlers — Logging handlers

5.16.6.11 NTEventLogHandler
...........................

The *note NTEventLogHandler: 2f02. class, located in the
‘logging.handlers’ module, supports sending logging messages to a local
Windows NT, Windows 2000 or Windows XP event log.  Before you can use
it, you need Mark Hammond’s Win32 extensions for Python installed.

 -- Class: logging.handlers.NTEventLogHandler (appname, dllname=None,
          logtype='Application')

     Returns a new instance of the ‘NTEventLogHandler’ class.  The
     'appname' is used to define the application name as it appears in
     the event log.  An appropriate registry entry is created using this
     name.  The 'dllname' should give the fully qualified pathname of a
     .dll or .exe which contains message definitions to hold in the log
     (if not specified, ‘'win32service.pyd'’ is used - this is installed
     with the Win32 extensions and contains some basic placeholder
     message definitions.  Note that use of these placeholders will make
     your event logs big, as the entire message source is held in the
     log.  If you want slimmer logs, you have to pass in the name of
     your own .dll or .exe which contains the message definitions you
     want to use in the event log).  The 'logtype' is one of
     ‘'Application'’, ‘'System'’ or ‘'Security'’, and defaults to
     ‘'Application'’.

      -- Method: close ()

          At this point, you can remove the application name from the
          registry as a source of event log entries.  However, if you do
          this, you will not be able to see the events as you intended
          in the Event Log Viewer - it needs to be able to access the
          registry to get the .dll name.  The current version does not
          do this.

      -- Method: emit (record)

          Determines the message ID, event category and event type, and
          then logs the message in the NT event log.

      -- Method: getEventCategory (record)

          Returns the event category for the record.  Override this if
          you want to specify your own categories.  This version returns
          0.

      -- Method: getEventType (record)

          Returns the event type for the record.  Override this if you
          want to specify your own types.  This version does a mapping
          using the handler’s typemap attribute, which is set up in
          ‘__init__()’ to a dictionary which contains mappings for
          ‘DEBUG’, ‘INFO’, ‘WARNING’, ‘ERROR’ and ‘CRITICAL’.  If you
          are using your own levels, you will either need to override
          this method or place a suitable dictionary in the handler’s
          'typemap' attribute.

      -- Method: getMessageID (record)

          Returns the message ID for the record.  If you are using your
          own messages, you could do this by having the 'msg' passed to
          the logger being an ID rather than a format string.  Then, in
          here, you could use a dictionary lookup to get the message ID.
          This version returns 1, which is the base message ID in
          ‘win32service.pyd’.


File: python.info,  Node: SMTPHandler,  Next: MemoryHandler,  Prev: NTEventLogHandler,  Up: logging handlers — Logging handlers

5.16.6.12 SMTPHandler
.....................

The *note SMTPHandler: 166d. class, located in the ‘logging.handlers’
module, supports sending logging messages to an email address via SMTP.

 -- Class: logging.handlers.SMTPHandler (mailhost, fromaddr, toaddrs,
          subject, credentials=None, secure=None, timeout=1.0)

     Returns a new instance of the ‘SMTPHandler’ class.  The instance is
     initialized with the from and to addresses and subject line of the
     email.  The 'toaddrs' should be a list of strings.  To specify a
     non-standard SMTP port, use the (host, port) tuple format for the
     'mailhost' argument.  If you use a string, the standard SMTP port
     is used.  If your SMTP server requires authentication, you can
     specify a (username, password) tuple for the 'credentials'
     argument.

     To specify the use of a secure protocol (TLS), pass in a tuple to
     the 'secure' argument.  This will only be used when authentication
     credentials are supplied.  The tuple should be either an empty
     tuple, or a single-value tuple with the name of a keyfile, or a
     2-value tuple with the names of the keyfile and certificate file.
     (This tuple is passed to the *note smtplib.SMTP.starttls(): 117c.
     method.)

     A timeout can be specified for communication with the SMTP server
     using the 'timeout' argument.

     Changed in version 3.3: Added the 'timeout' parameter.

      -- Method: emit (record)

          Formats the record and sends it to the specified addressees.

      -- Method: getSubject (record)

          If you want to specify a subject line which is
          record-dependent, override this method.


File: python.info,  Node: MemoryHandler,  Next: HTTPHandler,  Prev: SMTPHandler,  Up: logging handlers — Logging handlers

5.16.6.13 MemoryHandler
.......................

The *note MemoryHandler: 2ebb. class, located in the ‘logging.handlers’
module, supports buffering of logging records in memory, periodically
flushing them to a 'target' handler.  Flushing occurs whenever the
buffer is full, or when an event of a certain severity or greater is
seen.

*note MemoryHandler: 2ebb. is a subclass of the more general *note
BufferingHandler: 2f0e, which is an abstract class.  This buffers
logging records in memory.  Whenever each record is added to the buffer,
a check is made by calling ‘shouldFlush()’ to see if the buffer should
be flushed.  If it should, then ‘flush()’ is expected to do the
flushing.

 -- Class: logging.handlers.BufferingHandler (capacity)

     Initializes the handler with a buffer of the specified capacity.
     Here, 'capacity' means the number of logging records buffered.

      -- Method: emit (record)

          Append the record to the buffer.  If *note shouldFlush():
          2f10. returns true, call *note flush(): 2f11. to process the
          buffer.

      -- Method: flush ()

          For a ‘BufferingHandler’ instance, flushing means that it sets
          the buffer to an empty list.  This method can be overwritten
          to implement more useful flushing behavior.

      -- Method: shouldFlush (record)

          Return ‘True’ if the buffer is up to capacity.  This method
          can be overridden to implement custom flushing strategies.

 -- Class: logging.handlers.MemoryHandler (capacity, flushLevel=ERROR,
          target=None, flushOnClose=True)

     Returns a new instance of the ‘MemoryHandler’ class.  The instance
     is initialized with a buffer size of 'capacity' (number of records
     buffered).  If 'flushLevel' is not specified, ‘ERROR’ is used.  If
     no 'target' is specified, the target will need to be set using
     *note setTarget(): 2f12. before this handler does anything useful.
     If 'flushOnClose' is specified as ‘False’, then the buffer is 'not'
     flushed when the handler is closed.  If not specified or specified
     as ‘True’, the previous behaviour of flushing the buffer will occur
     when the handler is closed.

     Changed in version 3.6: The 'flushOnClose' parameter was added.

      -- Method: close ()

          Calls *note flush(): 2f14, sets the target to ‘None’ and
          clears the buffer.

      -- Method: flush ()

          For a ‘MemoryHandler’ instance, flushing means just sending
          the buffered records to the target, if there is one.  The
          buffer is also cleared when buffered records are sent to the
          target.  Override if you want different behavior.

      -- Method: setTarget (target)

          Sets the target handler for this handler.

      -- Method: shouldFlush (record)

          Checks for buffer full or a record at the 'flushLevel' or
          higher.


File: python.info,  Node: HTTPHandler,  Next: QueueHandler,  Prev: MemoryHandler,  Up: logging handlers — Logging handlers

5.16.6.14 HTTPHandler
.....................

The *note HTTPHandler: e5e. class, located in the ‘logging.handlers’
module, supports sending logging messages to a web server, using either
‘GET’ or ‘POST’ semantics.

 -- Class: logging.handlers.HTTPHandler (host, url, method='GET',
          secure=False, credentials=None, context=None)

     Returns a new instance of the ‘HTTPHandler’ class.  The 'host' can
     be of the form ‘host:port’, should you need to use a specific port
     number.  If no 'method' is specified, ‘GET’ is used.  If 'secure'
     is true, a HTTPS connection will be used.  The 'context' parameter
     may be set to a *note ssl.SSLContext: 294. instance to configure
     the SSL settings used for the HTTPS connection.  If 'credentials'
     is specified, it should be a 2-tuple consisting of userid and
     password, which will be placed in a HTTP ‘Authorization’ header
     using Basic authentication.  If you specify credentials, you should
     also specify secure=True so that your userid and password are not
     passed in cleartext across the wire.

     Changed in version 3.5: The 'context' parameter was added.

      -- Method: mapLogRecord (record)

          Provides a dictionary, based on ‘record’, which is to be
          URL-encoded and sent to the web server.  The default
          implementation just returns ‘record.__dict__’.  This method
          can be overridden if e.g.  only a subset of *note LogRecord:
          1021. is to be sent to the web server, or if more specific
          customization of what’s sent to the server is required.

      -- Method: emit (record)

          Sends the record to the web server as a URL-encoded
          dictionary.  The *note mapLogRecord(): 2f18. method is used to
          convert the record to the dictionary to be sent.

          Note: Since preparing a record for sending it to a web server
          is not the same as a generic formatting operation, using *note
          setFormatter(): 2e6b. to specify a *note Formatter: 14e6. for
          a ‘HTTPHandler’ has no effect.  Instead of calling *note
          format(): 2e74, this handler calls *note mapLogRecord(): 2f18.
          and then *note urllib.parse.urlencode(): ec9. to encode the
          dictionary in a form suitable for sending to a web server.


File: python.info,  Node: QueueHandler,  Next: QueueListener,  Prev: HTTPHandler,  Up: logging handlers — Logging handlers

5.16.6.15 QueueHandler
......................

Added in version 3.2.

The *note QueueHandler: 1907. class, located in the ‘logging.handlers’
module, supports sending logging messages to a queue, such as those
implemented in the *note queue: b6. or *note multiprocessing: 94.
modules.

Along with the *note QueueListener: e5f. class, *note QueueHandler:
1907. can be used to let handlers do their work on a separate thread
from the one which does the logging.  This is important in web
applications and also other service applications where threads servicing
clients need to respond as quickly as possible, while any potentially
slow operations (such as sending an email via *note SMTPHandler: 166d.)
are done on a separate thread.

 -- Class: logging.handlers.QueueHandler (queue)

     Returns a new instance of the ‘QueueHandler’ class.  The instance
     is initialized with the queue to send messages to.  The 'queue' can
     be any queue-like object; it’s used as-is by the *note enqueue():
     2f1c. method, which needs to know how to send messages to it.  The
     queue is not 'required' to have the task tracking API, which means
     that you can use *note SimpleQueue: b86. instances for 'queue'.

          Note: If you are using *note multiprocessing: 94, you should
          avoid using *note SimpleQueue: b86. and instead use *note
          multiprocessing.Queue: 192f.

          Warning: The *note multiprocessing: 94. module uses an
          internal logger created and accessed via *note get_logger():
          2f1d.  *note multiprocessing.Queue: 192f. will log ‘DEBUG’
          level messages upon items being queued.  If those log messages
          are processed by a ‘QueueHandler’ using the same
          ‘multiprocessing.Queue’ instance, it will cause a deadlock or
          infinite recursion.

      -- Method: emit (record)

          Enqueues the result of preparing the LogRecord.  Should an
          exception occur (e.g.  because a bounded queue has filled up),
          the *note handleError(): 2e72. method is called to handle the
          error.  This can result in the record silently being dropped
          (if *note logging.raiseExceptions: 123e. is ‘False’) or a
          message printed to ‘sys.stderr’ (if ‘logging.raiseExceptions’
          is ‘True’).

      -- Method: prepare (record)

          Prepares a record for queuing.  The object returned by this
          method is enqueued.

          The base implementation formats the record to merge the
          message, arguments, exception and stack information, if
          present.  It also removes unpickleable items from the record
          in-place.  Specifically, it overwrites the record’s ‘msg’ and
          ‘message’ attributes with the merged message (obtained by
          calling the handler’s *note format(): 622. method), and sets
          the ‘args’, ‘exc_info’ and ‘exc_text’ attributes to ‘None’.

          You might want to override this method if you want to convert
          the record to a dict or JSON string, or send a modified copy
          of the record while leaving the original intact.

               Note: The base implementation formats the message with
               arguments, sets the ‘message’ and ‘msg’ attributes to the
               formatted message and sets the ‘args’ and ‘exc_text’
               attributes to ‘None’ to allow pickling and to prevent
               further attempts at formatting.  This means that a
               handler on the *note QueueListener: e5f. side won’t have
               the information to do custom formatting, e.g.  of
               exceptions.  You may wish to subclass ‘QueueHandler’ and
               override this method to e.g.  avoid setting ‘exc_text’ to
               ‘None’.  Note that the ‘message’ / ‘msg’ / ‘args’ changes
               are related to ensuring the record is pickleable, and you
               might or might not be able to avoid doing that depending
               on whether your ‘args’ are pickleable.  (Note that you
               may have to consider not only your own code but also code
               in any libraries that you use.)

      -- Method: enqueue (record)

          Enqueues the record on the queue using ‘put_nowait()’; you may
          want to override this if you want to use blocking behaviour,
          or a timeout, or a customized queue implementation.

      -- Attribute: listener

          When created via configuration using *note dictConfig(): 11f4,
          this attribute will contain a *note QueueListener: e5f.
          instance for use with this handler.  Otherwise, it will be
          ‘None’.

          Added in version 3.12.


File: python.info,  Node: QueueListener,  Prev: QueueHandler,  Up: logging handlers — Logging handlers

5.16.6.16 QueueListener
.......................

Added in version 3.2.

The *note QueueListener: e5f. class, located in the ‘logging.handlers’
module, supports receiving logging messages from a queue, such as those
implemented in the *note queue: b6. or *note multiprocessing: 94.
modules.  The messages are received from a queue in an internal thread
and passed, on the same thread, to one or more handlers for processing.
While ‘QueueListener’ is not itself a handler, it is documented here
because it works hand-in-hand with *note QueueHandler: 1907.

Along with the *note QueueHandler: 1907. class, *note QueueListener:
e5f. can be used to let handlers do their work on a separate thread from
the one which does the logging.  This is important in web applications
and also other service applications where threads servicing clients need
to respond as quickly as possible, while any potentially slow operations
(such as sending an email via *note SMTPHandler: 166d.) are done on a
separate thread.

 -- Class: logging.handlers.QueueListener (queue, *handlers,
          respect_handler_level=False)

     Returns a new instance of the ‘QueueListener’ class.  The instance
     is initialized with the queue to send messages to and a list of
     handlers which will handle entries placed on the queue.  The queue
     can be any queue-like object; it’s passed as-is to the *note
     dequeue(): 2f22. method, which needs to know how to get messages
     from it.  The queue is not 'required' to have the task tracking API
     (though it’s used if available), which means that you can use *note
     SimpleQueue: b86. instances for 'queue'.

          Note: If you are using *note multiprocessing: 94, you should
          avoid using *note SimpleQueue: b86. and instead use *note
          multiprocessing.Queue: 192f.

     If ‘respect_handler_level’ is ‘True’, a handler’s level is
     respected (compared with the level for the message) when deciding
     whether to pass messages to that handler; otherwise, the behaviour
     is as in previous Python versions - to always pass each message to
     each handler.

     Changed in version 3.5: The ‘respect_handler_level’ argument was
     added.

      -- Method: dequeue (block)

          Dequeues a record and return it, optionally blocking.

          The base implementation uses ‘get()’.  You may want to
          override this method if you want to use timeouts or work with
          custom queue implementations.

      -- Method: prepare (record)

          Prepare a record for handling.

          This implementation just returns the passed-in record.  You
          may want to override this method if you need to do any custom
          marshalling or manipulation of the record before passing it to
          the handlers.

      -- Method: handle (record)

          Handle a record.

          This just loops through the handlers offering them the record
          to handle.  The actual object passed to the handlers is that
          which is returned from *note prepare(): 2f23.

      -- Method: start ()

          Starts the listener.

          This starts up a background thread to monitor the queue for
          LogRecords to process.

          Changed in version 3.13.4: Raises *note RuntimeError: 195. if
          called and the listener is already running.

      -- Method: stop ()

          Stops the listener.

          This asks the thread to terminate, and then waits for it to do
          so.  Note that if you don’t call this before your application
          exits, there may be some records still left on the queue,
          which won’t be processed.

      -- Method: enqueue_sentinel ()

          Writes a sentinel to the queue to tell the listener to quit.
          This implementation uses ‘put_nowait()’.  You may want to
          override this method if you want to use timeouts or work with
          custom queue implementations.

          Added in version 3.3.

See also
........

Module *note logging: 87.

     API reference for the logging module.

Module *note logging.config: 88.

     Configuration API for the logging module.


File: python.info,  Node: platform — Access to underlying platform’s identifying data,  Next: errno — Standard errno system symbols,  Prev: logging handlers — Logging handlers,  Up: Generic Operating System Services

5.16.7 ‘platform’ — Access to underlying platform’s identifying data
--------------------------------------------------------------------

'Source code:' Lib/platform.py(1)

__________________________________________________________________

     Note: Specific platforms listed alphabetically, with Linux included
     in the Unix section.

* Menu:

* Cross platform::
* Java platform::
* Windows platform::
* macOS platform::
* iOS platform::
* Unix platforms::
* Linux platforms::
* Android platform::
* Command-line usage: Command-line usage<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/platform.py


File: python.info,  Node: Cross platform,  Next: Java platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.1 Cross platform
.......................

 -- Function: platform.architecture (executable=sys.executable, bits='',
          linkage='')

     Queries the given executable (defaults to the Python interpreter
     binary) for various architecture information.

     Returns a tuple ‘(bits, linkage)’ which contain information about
     the bit architecture and the linkage format used for the
     executable.  Both values are returned as strings.

     Values that cannot be determined are returned as given by the
     parameter presets.  If bits is given as ‘''’, the ‘sizeof(pointer)’
     (or ‘sizeof(long)’ on Python version < 1.5.2) is used as indicator
     for the supported pointer size.

     The function relies on the system’s ‘file’ command to do the actual
     work.  This is available on most if not all Unix platforms and some
     non-Unix platforms and then only if the executable points to the
     Python interpreter.  Reasonable defaults are used when the above
     needs are not met.

          Note: On macOS (and perhaps other platforms), executable files
          may be universal files containing multiple architectures.

          To get at the “64-bitness” of the current interpreter, it is
          more reliable to query the *note sys.maxsize: 120a. attribute:

               is_64bits = sys.maxsize > 2**32

 -- Function: platform.machine ()

     Returns the machine type, e.g.  ‘'AMD64'’.  An empty string is
     returned if the value cannot be determined.

     The output is platform-dependent and may differ in casing and
     naming conventions.

 -- Function: platform.node ()

     Returns the computer’s network name (may not be fully qualified!).
     An empty string is returned if the value cannot be determined.

 -- Function: platform.platform (aliased=False, terse=False)

     Returns a single string identifying the underlying platform with as
     much useful information as possible.

     The output is intended to be 'human readable' rather than machine
     parseable.  It may look different on different platforms and this
     is intended.

     If 'aliased' is true, the function will use aliases for various
     platforms that report system names which differ from their common
     names, for example SunOS will be reported as Solaris.  The *note
     system_alias(): 2f2d. function is used to implement this.

     Setting 'terse' to true causes the function to return only the
     absolute minimum information needed to identify the platform.

     Changed in version 3.8: On macOS, the function now uses *note
     mac_ver(): 1bc4, if it returns a non-empty release string, to get
     the macOS version rather than the darwin version.

 -- Function: platform.processor ()

     Returns the (real) processor name, e.g.  ‘'amdk6'’.

     An empty string is returned if the value cannot be determined.
     Note that many platforms do not provide this information or simply
     return the same value as for *note machine(): 2f2b.  NetBSD does
     this.

 -- Function: platform.python_build ()

     Returns a tuple ‘(buildno, builddate)’ stating the Python build
     number and date as strings.

 -- Function: platform.python_compiler ()

     Returns a string identifying the compiler used for compiling
     Python.

 -- Function: platform.python_branch ()

     Returns a string identifying the Python implementation SCM branch.

 -- Function: platform.python_implementation ()

     Returns a string identifying the Python implementation.  Possible
     return values are: ‘CPython’, ‘IronPython’, ‘Jython’, ‘PyPy’.

 -- Function: platform.python_revision ()

     Returns a string identifying the Python implementation SCM
     revision.

 -- Function: platform.python_version ()

     Returns the Python version as string ‘'major.minor.patchlevel'’.

     Note that unlike the Python ‘sys.version’, the returned value will
     always include the patchlevel (it defaults to 0).

 -- Function: platform.python_version_tuple ()

     Returns the Python version as tuple ‘(major, minor, patchlevel)’ of
     strings.

     Note that unlike the Python ‘sys.version’, the returned value will
     always include the patchlevel (it defaults to ‘'0'’).

 -- Function: platform.release ()

     Returns the system’s release, e.g.  ‘'2.2.0'’ or ‘'NT'’.  An empty
     string is returned if the value cannot be determined.

 -- Function: platform.system ()

     Returns the system/OS name, such as ‘'Linux'’, ‘'Darwin'’,
     ‘'Java'’, ‘'Windows'’.  An empty string is returned if the value
     cannot be determined.

     On iOS and Android, this returns the user-facing OS name (i.e,
     ‘'iOS’, ‘'iPadOS'’ or ‘'Android'’).  To obtain the kernel name
     (‘'Darwin'’ or ‘'Linux'’), use *note os.uname(): 115a.

 -- Function: platform.system_alias (system, release, version)

     Returns ‘(system, release, version)’ aliased to common marketing
     names used for some systems.  It also does some reordering of the
     information in some cases where it would otherwise cause confusion.

 -- Function: platform.version ()

     Returns the system’s release version, e.g.  ‘'#3 on degas'’.  An
     empty string is returned if the value cannot be determined.

     On iOS and Android, this is the user-facing OS version.  To obtain
     the Darwin or Linux kernel version, use *note os.uname(): 115a.

 -- Function: platform.uname ()

     Fairly portable uname interface.  Returns a *note namedtuple():
     1ca. containing six attributes: *note system: 2008, *note node:
     2f2c, *note release: 2f36, *note version: 2f37, *note machine:
     2f2b, and *note processor: 2f2e.

     *note processor: 2f2e. is resolved late, on demand.

     Note: the first two attribute names differ from the names presented
     by *note os.uname(): 115a, where they are named ‘sysname’ and
     ‘nodename’.

     Entries which cannot be determined are set to ‘''’.

     Changed in version 3.3: Result changed from a tuple to a *note
     namedtuple(): 1ca.

     Changed in version 3.9: *note processor: 2f2e. is resolved late
     instead of immediately.


File: python.info,  Node: Java platform,  Next: Windows platform,  Prev: Cross platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.2 Java platform
......................

 -- Function: platform.java_ver (release='', vendor='', vminfo=('', '',
          ''), osinfo=('', '', ''))

     Version interface for Jython.

     Returns a tuple ‘(release, vendor, vminfo, osinfo)’ with 'vminfo'
     being a tuple ‘(vm_name, vm_release, vm_vendor)’ and 'osinfo' being
     a tuple ‘(os_name, os_version, os_arch)’.  Values which cannot be
     determined are set to the defaults given as parameters (which all
     default to ‘''’).

     Deprecated since version 3.13, will be removed in version 3.15: It
     was largely untested, had a confusing API, and was only useful for
     Jython support.


File: python.info,  Node: Windows platform,  Next: macOS platform,  Prev: Java platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.3 Windows platform
.........................

 -- Function: platform.win32_ver (release='', version='', csd='',
          ptype='')

     Get additional version information from the Windows Registry and
     return a tuple ‘(release, version, csd, ptype)’ referring to OS
     release, version number, CSD level (service pack) and OS type
     (multi/single processor).  Values which cannot be determined are
     set to the defaults given as parameters (which all default to an
     empty string).

     As a hint: 'ptype' is ‘'Uniprocessor Free'’ on single processor NT
     machines and ‘'Multiprocessor Free'’ on multi processor machines.
     The ‘'Free'’ refers to the OS version being free of debugging code.
     It could also state ‘'Checked'’ which means the OS version uses
     debugging code, i.e.  code that checks arguments, ranges, etc.

 -- Function: platform.win32_edition ()

     Returns a string representing the current Windows edition, or
     ‘None’ if the value cannot be determined.  Possible values include
     but are not limited to ‘'Enterprise'’, ‘'IoTUAP'’,
     ‘'ServerStandard'’, and ‘'nanoserver'’.

     Added in version 3.8.

 -- Function: platform.win32_is_iot ()

     Return ‘True’ if the Windows edition returned by *note
     win32_edition(): 2f3a. is recognized as an IoT edition.

     Added in version 3.8.


File: python.info,  Node: macOS platform,  Next: iOS platform,  Prev: Windows platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.4 macOS platform
.......................

 -- Function: platform.mac_ver (release='', versioninfo=('', '', ''),
          machine='')

     Get macOS version information and return it as tuple ‘(release,
     versioninfo, machine)’ with 'versioninfo' being a tuple ‘(version,
     dev_stage, non_release_version)’.

     Entries which cannot be determined are set to ‘''’.  All tuple
     entries are strings.


File: python.info,  Node: iOS platform,  Next: Unix platforms,  Prev: macOS platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.5 iOS platform
.....................

 -- Function: platform.ios_ver (system='', release='', model='',
          is_simulator=False)

     Get iOS version information and return it as a *note namedtuple():
     1ca. with the following attributes:

        * ‘system’ is the OS name; either ‘'iOS'’ or ‘'iPadOS'’.

        * ‘release’ is the iOS version number as a string (e.g.,
          ‘'17.2'’).

        * ‘model’ is the device model identifier; this will be a string
          like ‘'iPhone13,2'’ for a physical device, or ‘'iPhone'’ on a
          simulator.

        * ‘is_simulator’ is a boolean describing if the app is running
          on a simulator or a physical device.

     Entries which cannot be determined are set to the defaults given as
     parameters.


File: python.info,  Node: Unix platforms,  Next: Linux platforms,  Prev: iOS platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.6 Unix platforms
.......................

 -- Function: platform.libc_ver (executable=sys.executable, lib='',
          version='', chunksize=16384)

     Tries to determine the libc version against which the file
     executable (defaults to the Python interpreter) is linked.  Returns
     a tuple of strings ‘(lib, version)’ which default to the given
     parameters in case the lookup fails.

     Note that this function has intimate knowledge of how different
     libc versions add symbols to the executable is probably only usable
     for executables compiled using ‘gcc’.

     The file is read and scanned in chunks of 'chunksize' bytes.


File: python.info,  Node: Linux platforms,  Next: Android platform,  Prev: Unix platforms,  Up: platform — Access to underlying platform’s identifying data

5.16.7.7 Linux platforms
........................

 -- Function: platform.freedesktop_os_release ()

     Get operating system identification from ‘os-release’ file and
     return it as a dict.  The ‘os-release’ file is a freedesktop.org
     standard(1) and is available in most Linux distributions.  A
     noticeable exception is Android and Android-based distributions.

     Raises *note OSError: 41a. or subclass when neither
     ‘/etc/os-release’ nor ‘/usr/lib/os-release’ can be read.

     On success, the function returns a dictionary where keys and values
     are strings.  Values have their special characters like ‘"’ and ‘$’
     unquoted.  The fields ‘NAME’, ‘ID’, and ‘PRETTY_NAME’ are always
     defined according to the standard.  All other fields are optional.
     Vendors may include additional fields.

     Note that fields like ‘NAME’, ‘VERSION’, and ‘VARIANT’ are strings
     suitable for presentation to users.  Programs should use fields
     like ‘ID’, ‘ID_LIKE’, ‘VERSION_ID’, or ‘VARIANT_ID’ to identify
     Linux distributions.

     Example:

          def get_like_distro():
              info = platform.freedesktop_os_release()
              ids = [info["ID"]]
              if "ID_LIKE" in info:
                  # ids are space separated and ordered by precedence
                  ids.extend(info["ID_LIKE"].split())
              return ids

     Added in version 3.10.

   ---------- Footnotes ----------

   (1) https://www.freedesktop.org/software/systemd/man/os-release.html


File: python.info,  Node: Android platform,  Next: Command-line usage<2>,  Prev: Linux platforms,  Up: platform — Access to underlying platform’s identifying data

5.16.7.8 Android platform
.........................

 -- Function: platform.android_ver (release='', api_level=0,
          manufacturer='', model='', device='', is_emulator=False)

     Get Android device information.  Returns a *note namedtuple(): 1ca.
     with the following attributes.  Values which cannot be determined
     are set to the defaults given as parameters.

        * ‘release’ - Android version, as a string (e.g.  ‘"14"’).

        * ‘api_level’ - API level of the running device, as an integer
          (e.g.  ‘34’ for Android 14).  To get the API level which
          Python was built against, see *note sys.getandroidapilevel():
          ba8.

        * ‘manufacturer’ - Manufacturer name(1).

        * ‘model’ - Model name(2) – typically the marketing name or
          model number.

        * ‘device’ - Device name(3) – typically the model number or a
          codename.

        * ‘is_emulator’ - ‘True’ if the device is an emulator; ‘False’
          if it’s a physical device.

     Google maintains a list of known model and device names(4).

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) 
https://developer.android.com/reference/android/os/Build#MANUFACTURER

   (2) https://developer.android.com/reference/android/os/Build#MODEL

   (3) https://developer.android.com/reference/android/os/Build#DEVICE

   (4) https://storage.googleapis.com/play_public/supported_devices.html


File: python.info,  Node: Command-line usage<2>,  Prev: Android platform,  Up: platform — Access to underlying platform’s identifying data

5.16.7.9 Command-line usage
...........................

‘platform’ can also be invoked directly using the *note -m: 5e4. switch
of the interpreter:

     python -m platform [--terse] [--nonaliased] [{nonaliased,terse} ...]

The following options are accepted:

 -- Option: --terse

     Print terse information about the platform.  This is equivalent to
     calling *note platform.platform(): 1869. with the 'terse' argument
     set to ‘True’.

 -- Option: --nonaliased

     Print platform information without system/OS name aliasing.  This
     is equivalent to calling *note platform.platform(): 1869. with the
     'aliased' argument set to ‘True’.

You can also pass one or more positional arguments (‘terse’,
‘nonaliased’) to explicitly control the output format.  These behave
similarly to their corresponding options.


File: python.info,  Node: errno — Standard errno system symbols,  Next: ctypes — A foreign function library for Python,  Prev: platform — Access to underlying platform’s identifying data,  Up: Generic Operating System Services

5.16.8 ‘errno’ — Standard errno system symbols
----------------------------------------------

__________________________________________________________________

This module makes available standard ‘errno’ system symbols.  The value
of each symbol is the corresponding integer value.  The names and
descriptions are borrowed from ‘linux/include/errno.h’, which should be
all-inclusive.

 -- Data: errno.errorcode

     Dictionary providing a mapping from the errno value to the string
     name in the underlying system.  For instance,
     ‘errno.errorcode[errno.EPERM]’ maps to ‘'EPERM'’.

To translate a numeric error code to an error message, use *note
os.strerror(): 2d21.

Of the following list, symbols that are not used on the current platform
are not defined by the module.  The specific list of defined symbols is
available as ‘errno.errorcode.keys()’.  Symbols available can include:

 -- Data: errno.EPERM

     Operation not permitted.  This error is mapped to the exception
     *note PermissionError: d6b.

 -- Data: errno.ENOENT

     No such file or directory.  This error is mapped to the exception
     *note FileNotFoundError: 42e.

 -- Data: errno.ESRCH

     No such process.  This error is mapped to the exception *note
     ProcessLookupError: 1099.

 -- Data: errno.EINTR

     Interrupted system call.  This error is mapped to the exception
     *note InterruptedError: db6.

 -- Data: errno.EIO

     I/O error

 -- Data: errno.ENXIO

     No such device or address

 -- Data: errno.E2BIG

     Arg list too long

 -- Data: errno.ENOEXEC

     Exec format error

 -- Data: errno.EBADF

     Bad file number

 -- Data: errno.ECHILD

     No child processes.  This error is mapped to the exception *note
     ChildProcessError: 1096.

 -- Data: errno.EAGAIN

     Try again.  This error is mapped to the exception *note
     BlockingIOError: 1095.

 -- Data: errno.ENOMEM

     Out of memory

 -- Data: errno.EACCES

     Permission denied.  This error is mapped to the exception *note
     PermissionError: d6b.

 -- Data: errno.EFAULT

     Bad address

 -- Data: errno.ENOTBLK

     Block device required

 -- Data: errno.EBUSY

     Device or resource busy

 -- Data: errno.EEXIST

     File exists.  This error is mapped to the exception *note
     FileExistsError: 105b.

 -- Data: errno.EXDEV

     Cross-device link

 -- Data: errno.ENODEV

     No such device

 -- Data: errno.ENOTDIR

     Not a directory.  This error is mapped to the exception *note
     NotADirectoryError: 1098.

 -- Data: errno.EISDIR

     Is a directory.  This error is mapped to the exception *note
     IsADirectoryError: 1097.

 -- Data: errno.EINVAL

     Invalid argument

 -- Data: errno.ENFILE

     File table overflow

 -- Data: errno.EMFILE

     Too many open files

 -- Data: errno.ENOTTY

     Not a typewriter

 -- Data: errno.ETXTBSY

     Text file busy

 -- Data: errno.EFBIG

     File too large

 -- Data: errno.ENOSPC

     No space left on device

 -- Data: errno.ESPIPE

     Illegal seek

 -- Data: errno.EROFS

     Read-only file system

 -- Data: errno.EMLINK

     Too many links

 -- Data: errno.EPIPE

     Broken pipe.  This error is mapped to the exception *note
     BrokenPipeError: 109a.

 -- Data: errno.EDOM

     Math argument out of domain of func

 -- Data: errno.ERANGE

     Math result not representable

 -- Data: errno.EDEADLK

     Resource deadlock would occur

 -- Data: errno.ENAMETOOLONG

     File name too long

 -- Data: errno.ENOLCK

     No record locks available

 -- Data: errno.ENOSYS

     Function not implemented

 -- Data: errno.ENOTEMPTY

     Directory not empty

 -- Data: errno.ELOOP

     Too many symbolic links encountered

 -- Data: errno.EWOULDBLOCK

     Operation would block.  This error is mapped to the exception *note
     BlockingIOError: 1095.

 -- Data: errno.ENOMSG

     No message of desired type

 -- Data: errno.EIDRM

     Identifier removed

 -- Data: errno.ECHRNG

     Channel number out of range

 -- Data: errno.EL2NSYNC

     Level 2 not synchronized

 -- Data: errno.EL3HLT

     Level 3 halted

 -- Data: errno.EL3RST

     Level 3 reset

 -- Data: errno.ELNRNG

     Link number out of range

 -- Data: errno.EUNATCH

     Protocol driver not attached

 -- Data: errno.ENOCSI

     No CSI structure available

 -- Data: errno.EL2HLT

     Level 2 halted

 -- Data: errno.EBADE

     Invalid exchange

 -- Data: errno.EBADR

     Invalid request descriptor

 -- Data: errno.EXFULL

     Exchange full

 -- Data: errno.ENOANO

     No anode

 -- Data: errno.EBADRQC

     Invalid request code

 -- Data: errno.EBADSLT

     Invalid slot

 -- Data: errno.EDEADLOCK

     File locking deadlock error

 -- Data: errno.EBFONT

     Bad font file format

 -- Data: errno.ENOSTR

     Device not a stream

 -- Data: errno.ENODATA

     No data available

 -- Data: errno.ETIME

     Timer expired

 -- Data: errno.ENOSR

     Out of streams resources

 -- Data: errno.ENONET

     Machine is not on the network

 -- Data: errno.ENOPKG

     Package not installed

 -- Data: errno.EREMOTE

     Object is remote

 -- Data: errno.ENOLINK

     Link has been severed

 -- Data: errno.EADV

     Advertise error

 -- Data: errno.ESRMNT

     Srmount error

 -- Data: errno.ECOMM

     Communication error on send

 -- Data: errno.EPROTO

     Protocol error

 -- Data: errno.EMULTIHOP

     Multihop attempted

 -- Data: errno.EDOTDOT

     RFS specific error

 -- Data: errno.EBADMSG

     Not a data message

 -- Data: errno.EOVERFLOW

     Value too large for defined data type

 -- Data: errno.ENOTUNIQ

     Name not unique on network

 -- Data: errno.EBADFD

     File descriptor in bad state

 -- Data: errno.EREMCHG

     Remote address changed

 -- Data: errno.ELIBACC

     Can not access a needed shared library

 -- Data: errno.ELIBBAD

     Accessing a corrupted shared library

 -- Data: errno.ELIBSCN

     .lib section in a.out corrupted

 -- Data: errno.ELIBMAX

     Attempting to link in too many shared libraries

 -- Data: errno.ELIBEXEC

     Cannot exec a shared library directly

 -- Data: errno.EILSEQ

     Illegal byte sequence

 -- Data: errno.ERESTART

     Interrupted system call should be restarted

 -- Data: errno.ESTRPIPE

     Streams pipe error

 -- Data: errno.EUSERS

     Too many users

 -- Data: errno.ENOTSOCK

     Socket operation on non-socket

 -- Data: errno.EDESTADDRREQ

     Destination address required

 -- Data: errno.EMSGSIZE

     Message too long

 -- Data: errno.EPROTOTYPE

     Protocol wrong type for socket

 -- Data: errno.ENOPROTOOPT

     Protocol not available

 -- Data: errno.EPROTONOSUPPORT

     Protocol not supported

 -- Data: errno.ESOCKTNOSUPPORT

     Socket type not supported

 -- Data: errno.EOPNOTSUPP

     Operation not supported on transport endpoint

 -- Data: errno.ENOTSUP

     Operation not supported

     Added in version 3.2.

 -- Data: errno.EPFNOSUPPORT

     Protocol family not supported

 -- Data: errno.EAFNOSUPPORT

     Address family not supported by protocol

 -- Data: errno.EADDRINUSE

     Address already in use

 -- Data: errno.EADDRNOTAVAIL

     Cannot assign requested address

 -- Data: errno.ENETDOWN

     Network is down

 -- Data: errno.ENETUNREACH

     Network is unreachable

 -- Data: errno.ENETRESET

     Network dropped connection because of reset

 -- Data: errno.ECONNABORTED

     Software caused connection abort.  This error is mapped to the
     exception *note ConnectionAbortedError: 109b.

 -- Data: errno.ECONNRESET

     Connection reset by peer.  This error is mapped to the exception
     *note ConnectionResetError: 109d.

 -- Data: errno.ENOBUFS

     No buffer space available

 -- Data: errno.EISCONN

     Transport endpoint is already connected

 -- Data: errno.ENOTCONN

     Transport endpoint is not connected

 -- Data: errno.ESHUTDOWN

     Cannot send after transport endpoint shutdown.  This error is
     mapped to the exception *note BrokenPipeError: 109a.

 -- Data: errno.ETOOMANYREFS

     Too many references: cannot splice

 -- Data: errno.ETIMEDOUT

     Connection timed out.  This error is mapped to the exception *note
     TimeoutError: 83b.

 -- Data: errno.ECONNREFUSED

     Connection refused.  This error is mapped to the exception *note
     ConnectionRefusedError: 109c.

 -- Data: errno.EHOSTDOWN

     Host is down

 -- Data: errno.EHOSTUNREACH

     No route to host

 -- Data: errno.EALREADY

     Operation already in progress.  This error is mapped to the
     exception *note BlockingIOError: 1095.

 -- Data: errno.EINPROGRESS

     Operation now in progress.  This error is mapped to the exception
     *note BlockingIOError: 1095.

 -- Data: errno.ESTALE

     Stale NFS file handle

 -- Data: errno.EUCLEAN

     Structure needs cleaning

 -- Data: errno.ENOTNAM

     Not a XENIX named type file

 -- Data: errno.ENAVAIL

     No XENIX semaphores available

 -- Data: errno.EISNAM

     Is a named type file

 -- Data: errno.EREMOTEIO

     Remote I/O error

 -- Data: errno.EDQUOT

     Quota exceeded

 -- Data: errno.EQFULL

     Interface output queue is full

     Added in version 3.11.

 -- Data: errno.ENOMEDIUM

     No medium found

 -- Data: errno.EMEDIUMTYPE

     Wrong medium type

 -- Data: errno.ENOKEY

     Required key not available

 -- Data: errno.EKEYEXPIRED

     Key has expired

 -- Data: errno.EKEYREVOKED

     Key has been revoked

 -- Data: errno.EKEYREJECTED

     Key was rejected by service

 -- Data: errno.ERFKILL

     Operation not possible due to RF-kill

 -- Data: errno.ELOCKUNMAPPED

     Locked lock was unmapped

 -- Data: errno.ENOTACTIVE

     Facility is not active

 -- Data: errno.EAUTH

     Authentication error

     Added in version 3.2.

 -- Data: errno.EBADARCH

     Bad CPU type in executable

     Added in version 3.2.

 -- Data: errno.EBADEXEC

     Bad executable (or shared library)

     Added in version 3.2.

 -- Data: errno.EBADMACHO

     Malformed Mach-o file

     Added in version 3.2.

 -- Data: errno.EDEVERR

     Device error

     Added in version 3.2.

 -- Data: errno.EFTYPE

     Inappropriate file type or format

     Added in version 3.2.

 -- Data: errno.ENEEDAUTH

     Need authenticator

     Added in version 3.2.

 -- Data: errno.ENOATTR

     Attribute not found

     Added in version 3.2.

 -- Data: errno.ENOPOLICY

     Policy not found

     Added in version 3.2.

 -- Data: errno.EPROCLIM

     Too many processes

     Added in version 3.2.

 -- Data: errno.EPROCUNAVAIL

     Bad procedure for program

     Added in version 3.2.

 -- Data: errno.EPROGMISMATCH

     Program version wrong

     Added in version 3.2.

 -- Data: errno.EPROGUNAVAIL

     RPC prog.  not avail

     Added in version 3.2.

 -- Data: errno.EPWROFF

     Device power is off

     Added in version 3.2.

 -- Data: errno.EBADRPC

     RPC struct is bad

     Added in version 3.2.

 -- Data: errno.ERPCMISMATCH

     RPC version wrong

     Added in version 3.2.

 -- Data: errno.ESHLIBVERS

     Shared library version mismatch

     Added in version 3.2.

 -- Data: errno.ENOTCAPABLE

     Capabilities insufficient.  This error is mapped to the exception
     *note PermissionError: d6b.

     *note Availability: 1ef7.: WASI, FreeBSD

     Added in version 3.11.1.

 -- Data: errno.ECANCELED

     Operation canceled

     Added in version 3.2.

 -- Data: errno.EOWNERDEAD

     Owner died

     Added in version 3.2.

 -- Data: errno.ENOTRECOVERABLE

     State not recoverable

     Added in version 3.2.


File: python.info,  Node: ctypes — A foreign function library for Python,  Prev: errno — Standard errno system symbols,  Up: Generic Operating System Services

5.16.9 ‘ctypes’ — A foreign function library for Python
-------------------------------------------------------

'Source code:' Lib/ctypes(1)

__________________________________________________________________

‘ctypes’ is a foreign function library for Python.  It provides C
compatible data types, and allows calling functions in DLLs or shared
libraries.  It can be used to wrap these libraries in pure Python.

* Menu:

* ctypes tutorial::
* ctypes reference::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ctypes


File: python.info,  Node: ctypes tutorial,  Next: ctypes reference,  Up: ctypes — A foreign function library for Python

5.16.9.1 ctypes tutorial
........................

Note: The code samples in this tutorial use *note doctest: 3a. to make
sure that they actually work.  Since some code samples behave
differently under Linux, Windows, or macOS, they contain doctest
directives in comments.

Note: Some code samples reference the ctypes *note c_int: 2fcd. type.
On platforms where ‘sizeof(long) == sizeof(int)’ it is an alias to *note
c_long: 2fce.  So, you should not be confused if ‘c_long’ is printed if
you would expect ‘c_int’ — they are actually the same type.

* Menu:

* Loading dynamic link libraries::
* Accessing functions from loaded dlls::
* Calling functions::
* Fundamental data types::
* Calling functions, continued: Calling functions continued.
* Calling variadic functions::
* Calling functions with your own custom data types::
* Specifying the required argument types (function prototypes): Specifying the required argument types function prototypes.
* Return types::
* Passing pointers (or; passing parameters by reference): Passing pointers or passing parameters by reference.
* Structures and unions::
* Structure/union alignment and byte order::
* Bit fields in structures and unions::
* Arrays::
* Pointers::
* Type conversions::
* Incomplete Types::
* Callback functions::
* Accessing values exported from dlls::
* Surprises::
* Variable-sized data types::


File: python.info,  Node: Loading dynamic link libraries,  Next: Accessing functions from loaded dlls,  Up: ctypes tutorial

5.16.9.2 Loading dynamic link libraries
.......................................

‘ctypes’ exports the 'cdll', and on Windows 'windll' and 'oledll'
objects, for loading dynamic link libraries.

You load libraries by accessing them as attributes of these objects.
'cdll' loads libraries which export functions using the standard ‘cdecl’
calling convention, while 'windll' libraries call functions using the
‘stdcall’ calling convention.  'oledll' also uses the ‘stdcall’ calling
convention, and assumes the functions return a Windows ‘HRESULT’ error
code.  The error code is used to automatically raise an *note OSError:
41a. exception when the function call fails.

Changed in version 3.3: Windows errors used to raise *note WindowsError:
1092, which is now an alias of *note OSError: 41a.

Here are some examples for Windows.  Note that ‘msvcrt’ is the MS
standard C library containing most standard C functions, and uses the
‘cdecl’ calling convention:

     >>> from ctypes import *
     >>> print(windll.kernel32)
     <WinDLL 'kernel32', handle ... at ...>
     >>> print(cdll.msvcrt)
     <CDLL 'msvcrt', handle ... at ...>
     >>> libc = cdll.msvcrt
     >>>

Windows appends the usual ‘.dll’ file suffix automatically.

     Note: Accessing the standard C library through ‘cdll.msvcrt’ will
     use an outdated version of the library that may be incompatible
     with the one being used by Python.  Where possible, use native
     Python functionality, or else import and use the ‘msvcrt’ module.

On Linux, it is required to specify the filename 'including' the
extension to load a library, so attribute access can not be used to load
libraries.  Either the *note LoadLibrary(): 2fd1. method of the dll
loaders should be used, or you should load the library by creating an
instance of CDLL by calling the constructor:

     >>> cdll.LoadLibrary("libc.so.6")
     <CDLL 'libc.so.6', handle ... at ...>
     >>> libc = CDLL("libc.so.6")
     >>> libc
     <CDLL 'libc.so.6', handle ... at ...>
     >>>


File: python.info,  Node: Accessing functions from loaded dlls,  Next: Calling functions,  Prev: Loading dynamic link libraries,  Up: ctypes tutorial

5.16.9.3 Accessing functions from loaded dlls
.............................................

Functions are accessed as attributes of dll objects:

     >>> libc.printf
     <_FuncPtr object at 0x...>
     >>> print(windll.kernel32.GetModuleHandleA)
     <_FuncPtr object at 0x...>
     >>> print(windll.kernel32.MyOwnFunction)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "ctypes.py", line 239, in __getattr__
         func = _StdcallFuncPtr(name, self)
     AttributeError: function 'MyOwnFunction' not found
     >>>

Note that win32 system dlls like ‘kernel32’ and ‘user32’ often export
ANSI as well as UNICODE versions of a function.  The UNICODE version is
exported with a ‘W’ appended to the name, while the ANSI version is
exported with an ‘A’ appended to the name.  The win32 ‘GetModuleHandle’
function, which returns a 'module handle' for a given module name, has
the following C prototype, and a macro is used to expose one of them as
‘GetModuleHandle’ depending on whether UNICODE is defined or not:

     /* ANSI version */
     HMODULE GetModuleHandleA(LPCSTR lpModuleName);
     /* UNICODE version */
     HMODULE GetModuleHandleW(LPCWSTR lpModuleName);

'windll' does not try to select one of them by magic, you must access
the version you need by specifying ‘GetModuleHandleA’ or
‘GetModuleHandleW’ explicitly, and then call it with bytes or string
objects respectively.

Sometimes, dlls export functions with names which aren’t valid Python
identifiers, like ‘"??2@YAPAXI@Z"’.  In this case you have to use *note
getattr(): bf0. to retrieve the function:

     >>> getattr(cdll.msvcrt, "??2@YAPAXI@Z")
     <_FuncPtr object at 0x...>
     >>>

On Windows, some dlls export functions not by name but by ordinal.
These functions can be accessed by indexing the dll object with the
ordinal number:

     >>> cdll.kernel32[1]
     <_FuncPtr object at 0x...>
     >>> cdll.kernel32[0]
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "ctypes.py", line 310, in __getitem__
         func = _StdcallFuncPtr(name, self)
     AttributeError: function ordinal 0 not found
     >>>


File: python.info,  Node: Calling functions,  Next: Fundamental data types,  Prev: Accessing functions from loaded dlls,  Up: ctypes tutorial

5.16.9.4 Calling functions
..........................

You can call these functions like any other Python callable.  This
example uses the ‘rand()’ function, which takes no arguments and returns
a pseudo-random integer:

     >>> print(libc.rand())
     1804289383

On Windows, you can call the ‘GetModuleHandleA()’ function, which
returns a win32 module handle (passing ‘None’ as single argument to call
it with a ‘NULL’ pointer):

     >>> print(hex(windll.kernel32.GetModuleHandleA(None)))
     0x1d000000
     >>>

*note ValueError: 202. is raised when you call an ‘stdcall’ function
with the ‘cdecl’ calling convention, or vice versa:

     >>> cdll.kernel32.GetModuleHandleA(None)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ValueError: Procedure probably called with not enough arguments (4 bytes missing)
     >>>

     >>> windll.msvcrt.printf(b"spam")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ValueError: Procedure probably called with too many arguments (4 bytes in excess)
     >>>

To find out the correct calling convention you have to look into the C
header file or the documentation for the function you want to call.

On Windows, ‘ctypes’ uses win32 structured exception handling to prevent
crashes from general protection faults when functions are called with
invalid argument values:

     >>> windll.kernel32.GetModuleHandleA(32)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     OSError: exception: access violation reading 0x00000020
     >>>

There are, however, enough ways to crash Python with ‘ctypes’, so you
should be careful anyway.  The *note faulthandler: 58. module can be
helpful in debugging crashes (e.g.  from segmentation faults produced by
erroneous C library calls).

‘None’, integers, bytes objects and (unicode) strings are the only
native Python objects that can directly be used as parameters in these
function calls.  ‘None’ is passed as a C ‘NULL’ pointer, bytes objects
and strings are passed as pointer to the memory block that contains
their data (char* or wchar_t*).  Python integers are passed as the
platform’s default C int type, their value is masked to fit into the C
type.

Before we move on calling functions with other parameter types, we have
to learn more about ‘ctypes’ data types.


File: python.info,  Node: Fundamental data types,  Next: Calling functions continued,  Prev: Calling functions,  Up: ctypes tutorial

5.16.9.5 Fundamental data types
...............................

‘ctypes’ defines a number of primitive C compatible data types:

ctypes type                C type                                         Python type
                                                                          
-----------------------------------------------------------------------------------------------------------
                                                                          
*note c_bool: 2fd8.        _Bool                                          bool (1)
                                                                          
                                                                          
*note c_char: 2fd9.        char                                           1-character bytes object
                                                                          
                                                                          
*note c_wchar: 2fda.       ‘wchar_t’                                      1-character string
                                                                          
                                                                          
*note c_byte: 1883.        char                                           int
                                                                          
                                                                          
*note c_ubyte: 1884.       unsigned char                                  int
                                                                          
                                                                          
*note c_short: 2fdb.       short                                          int
                                                                          
                                                                          
*note c_ushort: 2fdc.      unsigned short                                 int
                                                                          
                                                                          
*note c_int: 2fcd.         int                                            int
                                                                          
                                                                          
*note c_int8: 2fdd.        ‘int8_t’                                       int
                                                                          
                                                                          
*note c_int16: 2fde.       ‘int16_t’                                      int
                                                                          
                                                                          
*note c_int32: 2fdf.       ‘int32_t’                                      int
                                                                          
                                                                          
*note c_int64: 2fe0.       ‘int64_t’                                      int
                                                                          
                                                                          
*note c_uint: 2fe1.        unsigned int                                   int
                                                                          
                                                                          
*note c_uint8: 2fe2.       ‘uint8_t’                                      int
                                                                          
                                                                          
*note c_uint16: 2fe3.      ‘uint16_t’                                     int
                                                                          
                                                                          
*note c_uint32: 2fe4.      ‘uint32_t’                                     int
                                                                          
                                                                          
*note c_uint64: 2fe5.      ‘uint64_t’                                     int
                                                                          
                                                                          
*note c_long: 2fce.        long                                           int
                                                                          
                                                                          
*note c_ulong: 2fe6.       unsigned long                                  int
                                                                          
                                                                          
*note c_longlong: 2fe7.    __int64 or long long                           int
                                                                          
                                                                          
*note c_ulonglong: 2fe8.   unsigned __int64 or unsigned long long         int
                                                                          
                                                                          
*note c_size_t: 2fe9.      ‘size_t’                                       int
                                                                          
                                                                          
*note c_ssize_t: 1282.     ‘ssize_t’ or *note Py_ssize_t: a6e.            int
                                                                          
                                                                          
*note c_time_t: 1909.      ‘time_t’                                       int
                                                                          
                                                                          
*note c_float: 2fea.       float                                          float
                                                                          
                                                                          
*note c_double: 1a5e.      double                                         float
                                                                          
                                                                          
*note c_longdouble: 1a5f.  long double                                    float
                                                                          
                                                                          
*note c_char_p: 17f6.      char* (NUL terminated)                         bytes object or ‘None’
                                                                          
                                                                          
*note c_wchar_p: 17f7.     wchar_t* (NUL terminated)                      string or ‘None’
                                                                          
                                                                          
*note c_void_p: 17f8.      void*                                          int or ‘None’
                                                                          

  1. The constructor accepts any object with a truth value.

All these types can be created by calling them with an optional
initializer of the correct type and value:

     >>> c_int()
     c_long(0)
     >>> c_wchar_p("Hello, World")
     c_wchar_p(140018365411392)
     >>> c_ushort(-3)
     c_ushort(65533)
     >>>

Since these types are mutable, their value can also be changed
afterwards:

     >>> i = c_int(42)
     >>> print(i)
     c_long(42)
     >>> print(i.value)
     42
     >>> i.value = -99
     >>> print(i.value)
     -99
     >>>

Assigning a new value to instances of the pointer types *note c_char_p:
17f6, *note c_wchar_p: 17f7, and *note c_void_p: 17f8. changes the
'memory location' they point to, 'not the contents' of the memory block
(of course not, because Python string objects are immutable):

     >>> s = "Hello, World"
     >>> c_s = c_wchar_p(s)
     >>> print(c_s)
     c_wchar_p(139966785747344)
     >>> print(c_s.value)
     Hello World
     >>> c_s.value = "Hi, there"
     >>> print(c_s)              # the memory location has changed
     c_wchar_p(139966783348904)
     >>> print(c_s.value)
     Hi, there
     >>> print(s)                # first object is unchanged
     Hello, World
     >>>

You should be careful, however, not to pass them to functions expecting
pointers to mutable memory.  If you need mutable memory blocks, ctypes
has a *note create_string_buffer(): 2feb. function which creates these
in various ways.  The current memory block contents can be accessed (or
changed) with the ‘raw’ property; if you want to access it as NUL
terminated string, use the ‘value’ property:

     >>> from ctypes import *
     >>> p = create_string_buffer(3)            # create a 3 byte buffer, initialized to NUL bytes
     >>> print(sizeof(p), repr(p.raw))
     3 b'\x00\x00\x00'
     >>> p = create_string_buffer(b"Hello")     # create a buffer containing a NUL terminated string
     >>> print(sizeof(p), repr(p.raw))
     6 b'Hello\x00'
     >>> print(repr(p.value))
     b'Hello'
     >>> p = create_string_buffer(b"Hello", 10) # create a 10 byte buffer
     >>> print(sizeof(p), repr(p.raw))
     10 b'Hello\x00\x00\x00\x00\x00'
     >>> p.value = b"Hi"
     >>> print(sizeof(p), repr(p.raw))
     10 b'Hi\x00lo\x00\x00\x00\x00\x00'
     >>>

The *note create_string_buffer(): 2feb. function replaces the old
‘c_buffer()’ function (which is still available as an alias).  To create
a mutable memory block containing unicode characters of the C type
‘wchar_t’, use the *note create_unicode_buffer(): 1b5f. function.


File: python.info,  Node: Calling functions continued,  Next: Calling variadic functions,  Prev: Fundamental data types,  Up: ctypes tutorial

5.16.9.6 Calling functions, continued
.....................................

Note that printf prints to the real standard output channel, 'not' to
*note sys.stdout: aec, so these examples will only work at the console
prompt, not from within 'IDLE' or 'PythonWin':

     >>> printf = libc.printf
     >>> printf(b"Hello, %s\n", b"World!")
     Hello, World!
     14
     >>> printf(b"Hello, %S\n", "World!")
     Hello, World!
     14
     >>> printf(b"%d bottles of beer\n", 42)
     42 bottles of beer
     19
     >>> printf(b"%f bottles of beer\n", 42.5)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ctypes.ArgumentError: argument 2: TypeError: Don't know how to convert parameter 2
     >>>

As has been mentioned before, all Python types except integers, strings,
and bytes objects have to be wrapped in their corresponding ‘ctypes’
type, so that they can be converted to the required C data type:

     >>> printf(b"An int %d, a double %f\n", 1234, c_double(3.14))
     An int 1234, a double 3.140000
     31
     >>>


File: python.info,  Node: Calling variadic functions,  Next: Calling functions with your own custom data types,  Prev: Calling functions continued,  Up: ctypes tutorial

5.16.9.7 Calling variadic functions
...................................

On a lot of platforms calling variadic functions through ctypes is
exactly the same as calling functions with a fixed number of parameters.
On some platforms, and in particular ARM64 for Apple Platforms, the
calling convention for variadic functions is different than that for
regular functions.

On those platforms it is required to specify the *note argtypes: 1617.
attribute for the regular, non-variadic, function arguments:

     libc.printf.argtypes = [ctypes.c_char_p]

Because specifying the attribute does not inhibit portability it is
advised to always specify *note argtypes: 1617. for all variadic
functions.


File: python.info,  Node: Calling functions with your own custom data types,  Next: Specifying the required argument types function prototypes,  Prev: Calling variadic functions,  Up: ctypes tutorial

5.16.9.8 Calling functions with your own custom data types
..........................................................

You can also customize ‘ctypes’ argument conversion to allow instances
of your own classes be used as function arguments.  ‘ctypes’ looks for
an ‘_as_parameter_’ attribute and uses this as the function argument.
The attribute must be an integer, string, bytes, a ‘ctypes’ instance, or
an object with an ‘_as_parameter_’ attribute:

     >>> class Bottles:
     ...     def __init__(self, number):
     ...         self._as_parameter_ = number
     ...
     >>> bottles = Bottles(42)
     >>> printf(b"%d bottles of beer\n", bottles)
     42 bottles of beer
     19
     >>>

If you don’t want to store the instance’s data in the ‘_as_parameter_’
instance variable, you could define a *note property: 194. which makes
the attribute available on request.


File: python.info,  Node: Specifying the required argument types function prototypes,  Next: Return types,  Prev: Calling functions with your own custom data types,  Up: ctypes tutorial

5.16.9.9 Specifying the required argument types (function prototypes)
.....................................................................

It is possible to specify the required argument types of functions
exported from DLLs by setting the *note argtypes: 1617. attribute.

*note argtypes: 1617. must be a sequence of C data types (the ‘printf()’
function is probably not a good example here, because it takes a
variable number and different types of parameters depending on the
format string, on the other hand this is quite handy to experiment with
this feature):

     >>> printf.argtypes = [c_char_p, c_char_p, c_int, c_double]
     >>> printf(b"String '%s', Int %d, Double %f\n", b"Hi", 10, 2.2)
     String 'Hi', Int 10, Double 2.200000
     37
     >>>

Specifying a format protects against incompatible argument types (just
as a prototype for a C function), and tries to convert the arguments to
valid types:

     >>> printf(b"%d %d %d", 1, 2, 3)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ctypes.ArgumentError: argument 2: TypeError: 'int' object cannot be interpreted as ctypes.c_char_p
     >>> printf(b"%s %d %f\n", b"X", 2, 3)
     X 2 3.000000
     13
     >>>

If you have defined your own classes which you pass to function calls,
you have to implement a *note from_param(): 2ff4. class method for them
to be able to use them in the *note argtypes: 1617. sequence.  The
‘from_param()’ class method receives the Python object passed to the
function call, it should do a typecheck or whatever is needed to make
sure this object is acceptable, and then return the object itself, its
‘_as_parameter_’ attribute, or whatever you want to pass as the C
function argument in this case.  Again, the result should be an integer,
string, bytes, a ‘ctypes’ instance, or an object with an
‘_as_parameter_’ attribute.


File: python.info,  Node: Return types,  Next: Passing pointers or passing parameters by reference,  Prev: Specifying the required argument types function prototypes,  Up: ctypes tutorial

5.16.9.10 Return types
......................

By default functions are assumed to return the C int type.  Other return
types can be specified by setting the *note restype: 2ff7. attribute of
the function object.

The C prototype of ‘time()’ is ‘time_t time(time_t *)’.  Because
‘time_t’ might be of a different type than the default return type int,
you should specify the ‘restype’ attribute:

     >>> libc.time.restype = c_time_t

The argument types can be specified using *note argtypes: 1617.:

     >>> libc.time.argtypes = (POINTER(c_time_t),)

To call the function with a ‘NULL’ pointer as first argument, use
‘None’:

     >>> print(libc.time(None))
     1150640792

Here is a more advanced example, it uses the ‘strchr()’ function, which
expects a string pointer and a char, and returns a pointer to a string:

     >>> strchr = libc.strchr
     >>> strchr(b"abcdef", ord("d"))
     8059983
     >>> strchr.restype = c_char_p    # c_char_p is a pointer to a string
     >>> strchr(b"abcdef", ord("d"))
     b'def'
     >>> print(strchr(b"abcdef", ord("x")))
     None
     >>>

If you want to avoid the *note ord("x"): 209f. calls above, you can set
the *note argtypes: 1617. attribute, and the second argument will be
converted from a single character Python bytes object into a C char:

     >>> strchr.restype = c_char_p
     >>> strchr.argtypes = [c_char_p, c_char]
     >>> strchr(b"abcdef", b"d")
     b'def'
     >>> strchr(b"abcdef", b"def")
     Traceback (most recent call last):
     ctypes.ArgumentError: argument 2: TypeError: one character bytes, bytearray or integer expected
     >>> print(strchr(b"abcdef", b"x"))
     None
     >>> strchr(b"abcdef", b"d")
     b'def'
     >>>

You can also use a callable Python object (a function or a class for
example) as the *note restype: 2ff7. attribute, if the foreign function
returns an integer.  The callable will be called with the 'integer' the
C function returns, and the result of this call will be used as the
result of your function call.  This is useful to check for error return
values and automatically raise an exception:

     >>> GetModuleHandle = windll.kernel32.GetModuleHandleA
     >>> def ValidHandle(value):
     ...     if value == 0:
     ...         raise WinError()
     ...     return value
     ...
     >>>
     >>> GetModuleHandle.restype = ValidHandle
     >>> GetModuleHandle(None)
     486539264
     >>> GetModuleHandle("something silly")
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 3, in ValidHandle
     OSError: [Errno 126] The specified module could not be found.
     >>>

‘WinError’ is a function which will call Windows ‘FormatMessage()’ api
to get the string representation of an error code, and 'returns' an
exception.  ‘WinError’ takes an optional error code parameter, if no one
is used, it calls *note GetLastError(): 2ff8. to retrieve it.

Please note that a much more powerful error checking mechanism is
available through the *note errcheck: 2ff9. attribute; see the reference
manual for details.


File: python.info,  Node: Passing pointers or passing parameters by reference,  Next: Structures and unions,  Prev: Return types,  Up: ctypes tutorial

5.16.9.11 Passing pointers (or: passing parameters by reference)
................................................................

Sometimes a C api function expects a 'pointer' to a data type as
parameter, probably to write into the corresponding location, or if the
data is too large to be passed by value.  This is also known as 'passing
parameters by reference'.

‘ctypes’ exports the *note byref(): 2ffc. function which is used to pass
parameters by reference.  The same effect can be achieved with the *note
pointer(): 17f4. function, although ‘pointer()’ does a lot more work
since it constructs a real pointer object, so it is faster to use
‘byref()’ if you don’t need the pointer object in Python itself:

     >>> i = c_int()
     >>> f = c_float()
     >>> s = create_string_buffer(b'\000' * 32)
     >>> print(i.value, f.value, repr(s.value))
     0 0.0 b''
     >>> libc.sscanf(b"1 3.14 Hello", b"%d %f %s",
     ...             byref(i), byref(f), s)
     3
     >>> print(i.value, f.value, repr(s.value))
     1 3.1400001049 b'Hello'
     >>>


File: python.info,  Node: Structures and unions,  Next: Structure/union alignment and byte order,  Prev: Passing pointers or passing parameters by reference,  Up: ctypes tutorial

5.16.9.12 Structures and unions
...............................

Structures and unions must derive from the *note Structure: 1d4. and
*note Union: 1794. base classes which are defined in the ‘ctypes’
module.  Each subclass must define a *note _fields_: 2fff. attribute.
‘_fields_’ must be a list of '2-tuples', containing a 'field name' and a
'field type'.

The field type must be a ‘ctypes’ type like *note c_int: 2fcd, or any
other derived ‘ctypes’ type: structure, union, array, pointer.

Here is a simple example of a POINT structure, which contains two
integers named 'x' and 'y', and also shows how to initialize a structure
in the constructor:

     >>> from ctypes import *
     >>> class POINT(Structure):
     ...     _fields_ = [("x", c_int),
     ...                 ("y", c_int)]
     ...
     >>> point = POINT(10, 20)
     >>> print(point.x, point.y)
     10 20
     >>> point = POINT(y=5)
     >>> print(point.x, point.y)
     0 5
     >>> POINT(1, 2, 3)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: too many initializers
     >>>

You can, however, build much more complicated structures.  A structure
can itself contain other structures by using a structure as a field
type.

Here is a RECT structure which contains two POINTs named 'upperleft' and
'lowerright':

     >>> class RECT(Structure):
     ...     _fields_ = [("upperleft", POINT),
     ...                 ("lowerright", POINT)]
     ...
     >>> rc = RECT(point)
     >>> print(rc.upperleft.x, rc.upperleft.y)
     0 5
     >>> print(rc.lowerright.x, rc.lowerright.y)
     0 0
     >>>

Nested structures can also be initialized in the constructor in several
ways:

     >>> r = RECT(POINT(1, 2), POINT(3, 4))
     >>> r = RECT((1, 2), (3, 4))

Field *note descriptor: 1677.s can be retrieved from the 'class', they
are useful for debugging because they can provide useful information:

     >>> print(POINT.x)
     <Field type=c_long, ofs=0, size=4>
     >>> print(POINT.y)
     <Field type=c_long, ofs=4, size=4>
     >>>
     Warning: ‘ctypes’ does not support passing unions or structures
     with bit-fields to functions by value.  While this may work on
     32-bit x86, it’s not guaranteed by the library to work in the
     general case.  Unions and structures with bit-fields should always
     be passed to functions by pointer.


File: python.info,  Node: Structure/union alignment and byte order,  Next: Bit fields in structures and unions,  Prev: Structures and unions,  Up: ctypes tutorial

5.16.9.13 Structure/union alignment and byte order
..................................................

By default, Structure and Union fields are aligned in the same way the C
compiler does it.  It is possible to override this behavior by
specifying a *note _pack_: 3002. class attribute in the subclass
definition.  This must be set to a positive integer and specifies the
maximum alignment for the fields.  This is what ‘#pragma pack(n)’ also
does in MSVC. It is also possible to set a minimum alignment for how the
subclass itself is packed in the same way ‘#pragma align(n)’ works in
MSVC. This can be achieved by specifying a *note _align_: 1d5. class
attribute in the subclass definition.

‘ctypes’ uses the native byte order for Structures and Unions.  To build
structures with non-native byte order, you can use one of the *note
BigEndianStructure: 3003, *note LittleEndianStructure: 3004, *note
BigEndianUnion: 195c, and *note LittleEndianUnion: 195d. base classes.
These classes cannot contain pointer fields.


File: python.info,  Node: Bit fields in structures and unions,  Next: Arrays,  Prev: Structure/union alignment and byte order,  Up: ctypes tutorial

5.16.9.14 Bit fields in structures and unions
.............................................

It is possible to create structures and unions containing bit fields.
Bit fields are only possible for integer fields, the bit width is
specified as the third item in the *note _fields_: 2fff. tuples:

     >>> class Int(Structure):
     ...     _fields_ = [("first_16", c_int, 16),
     ...                 ("second_16", c_int, 16)]
     ...
     >>> print(Int.first_16)
     <Field type=c_long, ofs=0:0, bits=16>
     >>> print(Int.second_16)
     <Field type=c_long, ofs=0:16, bits=16>
     >>>


File: python.info,  Node: Arrays,  Next: Pointers,  Prev: Bit fields in structures and unions,  Up: ctypes tutorial

5.16.9.15 Arrays
................

Arrays are sequences, containing a fixed number of instances of the same
type.

The recommended way to create array types is by multiplying a data type
with a positive integer:

     TenPointsArrayType = POINT * 10

Here is an example of a somewhat artificial data type, a structure
containing 4 POINTs among other stuff:

     >>> from ctypes import *
     >>> class POINT(Structure):
     ...     _fields_ = ("x", c_int), ("y", c_int)
     ...
     >>> class MyStruct(Structure):
     ...     _fields_ = [("a", c_int),
     ...                 ("b", c_float),
     ...                 ("point_array", POINT * 4)]
     >>>
     >>> print(len(MyStruct().point_array))
     4
     >>>

Instances are created in the usual way, by calling the class:

     arr = TenPointsArrayType()
     for pt in arr:
         print(pt.x, pt.y)

The above code print a series of ‘0 0’ lines, because the array contents
is initialized to zeros.

Initializers of the correct type can also be specified:

     >>> from ctypes import *
     >>> TenIntegers = c_int * 10
     >>> ii = TenIntegers(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
     >>> print(ii)
     <c_long_Array_10 object at 0x...>
     >>> for i in ii: print(i, end=" ")
     ...
     1 2 3 4 5 6 7 8 9 10
     >>>


File: python.info,  Node: Pointers,  Next: Type conversions,  Prev: Arrays,  Up: ctypes tutorial

5.16.9.16 Pointers
..................

Pointer instances are created by calling the *note pointer(): 17f4.
function on a ‘ctypes’ type:

     >>> from ctypes import *
     >>> i = c_int(42)
     >>> pi = pointer(i)
     >>>

Pointer instances have a *note contents: 300b. attribute which returns
the object to which the pointer points, the ‘i’ object above:

     >>> pi.contents
     c_long(42)
     >>>

Note that ‘ctypes’ does not have OOR (original object return), it
constructs a new, equivalent object each time you retrieve an attribute:

     >>> pi.contents is i
     False
     >>> pi.contents is pi.contents
     False
     >>>

Assigning another *note c_int: 2fcd. instance to the pointer’s contents
attribute would cause the pointer to point to the memory location where
this is stored:

     >>> i = c_int(99)
     >>> pi.contents = i
     >>> pi.contents
     c_long(99)
     >>>

Pointer instances can also be indexed with integers:

     >>> pi[0]
     99
     >>>

Assigning to an integer index changes the pointed to value:

     >>> print(i)
     c_long(99)
     >>> pi[0] = 22
     >>> print(i)
     c_long(22)
     >>>

It is also possible to use indexes different from 0, but you must know
what you’re doing, just as in C: You can access or change arbitrary
memory locations.  Generally you only use this feature if you receive a
pointer from a C function, and you 'know' that the pointer actually
points to an array instead of a single item.

Behind the scenes, the *note pointer(): 17f4. function does more than
simply create pointer instances, it has to create pointer 'types' first.
This is done with the *note POINTER(): 17f5. function, which accepts any
‘ctypes’ type, and returns a new type:

     >>> PI = POINTER(c_int)
     >>> PI
     <class 'ctypes.LP_c_long'>
     >>> PI(42)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: expected c_long instead of int
     >>> PI(c_int(42))
     <ctypes.LP_c_long object at 0x...>
     >>>

Calling the pointer type without an argument creates a ‘NULL’ pointer.
‘NULL’ pointers have a ‘False’ boolean value:

     >>> null_ptr = POINTER(c_int)()
     >>> print(bool(null_ptr))
     False
     >>>

‘ctypes’ checks for ‘NULL’ when dereferencing pointers (but
dereferencing invalid non-‘NULL’ pointers would crash Python):

     >>> null_ptr[0]
     Traceback (most recent call last):
         ....
     ValueError: NULL pointer access
     >>>

     >>> null_ptr[0] = 1234
     Traceback (most recent call last):
         ....
     ValueError: NULL pointer access
     >>>


File: python.info,  Node: Type conversions,  Next: Incomplete Types,  Prev: Pointers,  Up: ctypes tutorial

5.16.9.17 Type conversions
..........................

Usually, ctypes does strict type checking.  This means, if you have
‘POINTER(c_int)’ in the *note argtypes: 1617. list of a function or as
the type of a member field in a structure definition, only instances of
exactly the same type are accepted.  There are some exceptions to this
rule, where ctypes accepts other objects.  For example, you can pass
compatible array instances instead of pointer types.  So, for
‘POINTER(c_int)’, ctypes accepts an array of c_int:

     >>> class Bar(Structure):
     ...     _fields_ = [("count", c_int), ("values", POINTER(c_int))]
     ...
     >>> bar = Bar()
     >>> bar.values = (c_int * 3)(1, 2, 3)
     >>> bar.count = 3
     >>> for i in range(bar.count):
     ...     print(bar.values[i])
     ...
     1
     2
     3
     >>>

In addition, if a function argument is explicitly declared to be a
pointer type (such as ‘POINTER(c_int)’) in *note argtypes: 1617, an
object of the pointed type (‘c_int’ in this case) can be passed to the
function.  ctypes will apply the required *note byref(): 2ffc.
conversion in this case automatically.

To set a POINTER type field to ‘NULL’, you can assign ‘None’:

     >>> bar.values = None
     >>>

Sometimes you have instances of incompatible types.  In C, you can cast
one type into another type.  ‘ctypes’ provides a *note cast(): 300e.
function which can be used in the same way.  The ‘Bar’ structure defined
above accepts ‘POINTER(c_int)’ pointers or *note c_int: 2fcd. arrays for
its ‘values’ field, but not instances of other types:

     >>> bar.values = (c_byte * 4)()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: incompatible types, c_byte_Array_4 instance instead of LP_c_long instance
     >>>

For these cases, the *note cast(): 300e. function is handy.

The *note cast(): 300e. function can be used to cast a ctypes instance
into a pointer to a different ctypes data type.  ‘cast()’ takes two
parameters, a ctypes object that is or can be converted to a pointer of
some kind, and a ctypes pointer type.  It returns an instance of the
second argument, which references the same memory block as the first
argument:

     >>> a = (c_byte * 4)()
     >>> cast(a, POINTER(c_int))
     <ctypes.LP_c_long object at ...>
     >>>

So, *note cast(): 300e. can be used to assign to the ‘values’ field of
‘Bar’ the structure:

     >>> bar = Bar()
     >>> bar.values = cast((c_byte * 4)(), POINTER(c_int))
     >>> print(bar.values[0])
     0
     >>>


File: python.info,  Node: Incomplete Types,  Next: Callback functions,  Prev: Type conversions,  Up: ctypes tutorial

5.16.9.18 Incomplete Types
..........................

'Incomplete Types' are structures, unions or arrays whose members are
not yet specified.  In C, they are specified by forward declarations,
which are defined later:

     struct cell; /* forward declaration */

     struct cell {
         char *name;
         struct cell *next;
     };

The straightforward translation into ctypes code would be this, but it
does not work:

     >>> class cell(Structure):
     ...     _fields_ = [("name", c_char_p),
     ...                 ("next", POINTER(cell))]
     ...
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 2, in cell
     NameError: name 'cell' is not defined
     >>>

because the new ‘class cell’ is not available in the class statement
itself.  In ‘ctypes’, we can define the ‘cell’ class and set the *note
_fields_: 2fff. attribute later, after the class statement:

     >>> from ctypes import *
     >>> class cell(Structure):
     ...     pass
     ...
     >>> cell._fields_ = [("name", c_char_p),
     ...                  ("next", POINTER(cell))]
     >>>

Let’s try it.  We create two instances of ‘cell’, and let them point to
each other, and finally follow the pointer chain a few times:

     >>> c1 = cell()
     >>> c1.name = b"foo"
     >>> c2 = cell()
     >>> c2.name = b"bar"
     >>> c1.next = pointer(c2)
     >>> c2.next = pointer(c1)
     >>> p = c1
     >>> for i in range(8):
     ...     print(p.name, end=" ")
     ...     p = p.next[0]
     ...
     foo bar foo bar foo bar foo bar
     >>>


File: python.info,  Node: Callback functions,  Next: Accessing values exported from dlls,  Prev: Incomplete Types,  Up: ctypes tutorial

5.16.9.19 Callback functions
............................

‘ctypes’ allows creating C callable function pointers from Python
callables.  These are sometimes called 'callback functions'.

First, you must create a class for the callback function.  The class
knows the calling convention, the return type, and the number and types
of arguments this function will receive.

The *note CFUNCTYPE(): 3013. factory function creates types for callback
functions using the ‘cdecl’ calling convention.  On Windows, the *note
WINFUNCTYPE(): 3014. factory function creates types for callback
functions using the ‘stdcall’ calling convention.

Both of these factory functions are called with the result type as first
argument, and the callback functions expected argument types as the
remaining arguments.

I will present an example here which uses the standard C library’s
‘qsort()’ function, that is used to sort items with the help of a
callback function.  ‘qsort()’ will be used to sort an array of integers:

     >>> IntArray5 = c_int * 5
     >>> ia = IntArray5(5, 1, 7, 33, 99)
     >>> qsort = libc.qsort
     >>> qsort.restype = None
     >>>

‘qsort()’ must be called with a pointer to the data to sort, the number
of items in the data array, the size of one item, and a pointer to the
comparison function, the callback.  The callback will then be called
with two pointers to items, and it must return a negative integer if the
first item is smaller than the second, a zero if they are equal, and a
positive integer otherwise.

So our callback function receives pointers to integers, and must return
an integer.  First we create the ‘type’ for the callback function:

     >>> CMPFUNC = CFUNCTYPE(c_int, POINTER(c_int), POINTER(c_int))
     >>>

To get started, here is a simple callback that shows the values it gets
passed:

     >>> def py_cmp_func(a, b):
     ...     print("py_cmp_func", a[0], b[0])
     ...     return 0
     ...
     >>> cmp_func = CMPFUNC(py_cmp_func)
     >>>

The result:

     >>> qsort(ia, len(ia), sizeof(c_int), cmp_func)
     py_cmp_func 5 1
     py_cmp_func 33 99
     py_cmp_func 7 33
     py_cmp_func 5 7
     py_cmp_func 1 7
     >>>

Now we can actually compare the two items and return a useful result:

     >>> def py_cmp_func(a, b):
     ...     print("py_cmp_func", a[0], b[0])
     ...     return a[0] - b[0]
     ...
     >>>
     >>> qsort(ia, len(ia), sizeof(c_int), CMPFUNC(py_cmp_func))
     py_cmp_func 5 1
     py_cmp_func 33 99
     py_cmp_func 7 33
     py_cmp_func 1 7
     py_cmp_func 5 7
     >>>

As we can easily check, our array is sorted now:

     >>> for i in ia: print(i, end=" ")
     ...
     1 5 7 33 99
     >>>

The function factories can be used as decorator factories, so we may as
well write:

     >>> @CFUNCTYPE(c_int, POINTER(c_int), POINTER(c_int))
     ... def py_cmp_func(a, b):
     ...     print("py_cmp_func", a[0], b[0])
     ...     return a[0] - b[0]
     ...
     >>> qsort(ia, len(ia), sizeof(c_int), py_cmp_func)
     py_cmp_func 5 1
     py_cmp_func 33 99
     py_cmp_func 7 33
     py_cmp_func 1 7
     py_cmp_func 5 7
     >>>

     Note: Make sure you keep references to *note CFUNCTYPE(): 3013.
     objects as long as they are used from C code.  ‘ctypes’ doesn’t,
     and if you don’t, they may be garbage collected, crashing your
     program when a callback is made.

     Also, note that if the callback function is called in a thread
     created outside of Python’s control (e.g.  by the foreign code that
     calls the callback), ctypes creates a new dummy Python thread on
     every invocation.  This behavior is correct for most purposes, but
     it means that values stored with *note threading.local: 1650. will
     'not' survive across different callbacks, even when those calls are
     made from the same C thread.


File: python.info,  Node: Accessing values exported from dlls,  Next: Surprises,  Prev: Callback functions,  Up: ctypes tutorial

5.16.9.20 Accessing values exported from dlls
.............................................

Some shared libraries not only export functions, they also export
variables.  An example in the Python library itself is the *note
Py_Version: 759, Python runtime version number encoded in a single
constant integer.

‘ctypes’ can access values like this with the *note in_dll(): 3017.
class methods of the type.  'pythonapi' is a predefined symbol giving
access to the Python C api:

     >>> version = ctypes.c_int.in_dll(ctypes.pythonapi, "Py_Version")
     >>> print(hex(version.value))
     0x30c00a0

An extended example which also demonstrates the use of pointers accesses
the *note PyImport_FrozenModules: 3018. pointer exported by Python.

Quoting the docs for that value:

     This pointer is initialized to point to an array of *note _frozen:
     778. records, terminated by one whose members are all ‘NULL’ or
     zero.  When a frozen module is imported, it is searched in this
     table.  Third-party code could play tricks with this to provide a
     dynamically created collection of frozen modules.

So manipulating this pointer could even prove useful.  To restrict the
example size, we show only how this table can be read with ‘ctypes’:

     >>> from ctypes import *
     >>>
     >>> class struct_frozen(Structure):
     ...     _fields_ = [("name", c_char_p),
     ...                 ("code", POINTER(c_ubyte)),
     ...                 ("size", c_int),
     ...                 ("get_code", POINTER(c_ubyte)),  # Function pointer
     ...                ]
     ...
     >>>

We have defined the *note _frozen: 778. data type, so we can get the
pointer to the table:

     >>> FrozenTable = POINTER(struct_frozen)
     >>> table = FrozenTable.in_dll(pythonapi, "_PyImport_FrozenBootstrap")
     >>>

Since ‘table’ is a ‘pointer’ to the array of ‘struct_frozen’ records, we
can iterate over it, but we just have to make sure that our loop
terminates, because pointers have no size.  Sooner or later it would
probably crash with an access violation or whatever, so it’s better to
break out of the loop when we hit the ‘NULL’ entry:

     >>> for item in table:
     ...     if item.name is None:
     ...         break
     ...     print(item.name.decode("ascii"), item.size)
     ...
     _frozen_importlib 31764
     _frozen_importlib_external 41499
     zipimport 12345
     >>>

The fact that standard Python has a frozen module and a frozen package
(indicated by the negative ‘size’ member) is not well known, it is only
used for testing.  Try it out with ‘import __hello__’ for example.


File: python.info,  Node: Surprises,  Next: Variable-sized data types,  Prev: Accessing values exported from dlls,  Up: ctypes tutorial

5.16.9.21 Surprises
...................

There are some edges in ‘ctypes’ where you might expect something other
than what actually happens.

Consider the following example:

     >>> from ctypes import *
     >>> class POINT(Structure):
     ...     _fields_ = ("x", c_int), ("y", c_int)
     ...
     >>> class RECT(Structure):
     ...     _fields_ = ("a", POINT), ("b", POINT)
     ...
     >>> p1 = POINT(1, 2)
     >>> p2 = POINT(3, 4)
     >>> rc = RECT(p1, p2)
     >>> print(rc.a.x, rc.a.y, rc.b.x, rc.b.y)
     1 2 3 4
     >>> # now swap the two points
     >>> rc.a, rc.b = rc.b, rc.a
     >>> print(rc.a.x, rc.a.y, rc.b.x, rc.b.y)
     3 4 3 4
     >>>

Hm.  We certainly expected the last statement to print ‘3 4 1 2’.  What
happened?  Here are the steps of the ‘rc.a, rc.b = rc.b, rc.a’ line
above:

     >>> temp0, temp1 = rc.b, rc.a
     >>> rc.a = temp0
     >>> rc.b = temp1
     >>>

Note that ‘temp0’ and ‘temp1’ are objects still using the internal
buffer of the ‘rc’ object above.  So executing ‘rc.a = temp0’ copies the
buffer contents of ‘temp0’ into ‘rc’ ‘s buffer.  This, in turn, changes
the contents of ‘temp1’.  So, the last assignment ‘rc.b = temp1’,
doesn’t have the expected effect.

Keep in mind that retrieving sub-objects from Structure, Unions, and
Arrays doesn’t 'copy' the sub-object, instead it retrieves a wrapper
object accessing the root-object’s underlying buffer.

Another example that may behave differently from what one would expect
is this:

     >>> s = c_char_p()
     >>> s.value = b"abc def ghi"
     >>> s.value
     b'abc def ghi'
     >>> s.value is s.value
     False
     >>>

     Note: Objects instantiated from *note c_char_p: 17f6. can only have
     their value set to bytes or integers.

Why is it printing ‘False’?  ctypes instances are objects containing a
memory block plus some *note descriptor: 1677.s accessing the contents
of the memory.  Storing a Python object in the memory block does not
store the object itself, instead the ‘contents’ of the object is stored.
Accessing the contents again constructs a new Python object each time!


File: python.info,  Node: Variable-sized data types,  Prev: Surprises,  Up: ctypes tutorial

5.16.9.22 Variable-sized data types
...................................

‘ctypes’ provides some support for variable-sized arrays and structures.

The *note resize(): 301d. function can be used to resize the memory
buffer of an existing ctypes object.  The function takes the object as
first argument, and the requested size in bytes as the second argument.
The memory block cannot be made smaller than the natural memory block
specified by the objects type, a *note ValueError: 202. is raised if
this is tried:

     >>> short_array = (c_short * 4)()
     >>> print(sizeof(short_array))
     8
     >>> resize(short_array, 4)
     Traceback (most recent call last):
         ...
     ValueError: minimum size is 8
     >>> resize(short_array, 32)
     >>> sizeof(short_array)
     32
     >>> sizeof(type(short_array))
     8
     >>>

This is nice and fine, but how would one access the additional elements
contained in this array?  Since the type still only knows about 4
elements, we get errors accessing other elements:

     >>> short_array[:]
     [0, 0, 0, 0]
     >>> short_array[7]
     Traceback (most recent call last):
         ...
     IndexError: invalid index
     >>>

Another way to use variable-sized data types with ‘ctypes’ is to use the
dynamic nature of Python, and (re-)define the data type after the
required size is already known, on a case by case basis.


File: python.info,  Node: ctypes reference,  Prev: ctypes tutorial,  Up: ctypes — A foreign function library for Python

5.16.9.23 ctypes reference
..........................

* Menu:

* Finding shared libraries::
* Loading shared libraries::
* Foreign functions::
* Function prototypes::
* Utility functions::
* Data types: Data types<2>.
* Fundamental data types: Fundamental data types<2>.
* Structured data types::
* Arrays and pointers::


File: python.info,  Node: Finding shared libraries,  Next: Loading shared libraries,  Up: ctypes reference

5.16.9.24 Finding shared libraries
..................................

When programming in a compiled language, shared libraries are accessed
when compiling/linking a program, and when the program is run.

The purpose of the *note find_library(): d72. function is to locate a
library in a way similar to what the compiler or runtime loader does (on
platforms with several versions of a shared library the most recent
should be loaded), while the ctypes library loaders act like when a
program is run, and call the runtime loader directly.

The ‘ctypes.util’ module provides a function which can help to determine
the library to load.

 -- Data: ctypes.util.find_library (name)

     Try to find a library and return a pathname.  'name' is the library
     name without any prefix like 'lib', suffix like ‘.so’, ‘.dylib’ or
     version number (this is the form used for the posix linker option
     ‘-l’).  If no library can be found, returns ‘None’.

The exact functionality is system dependent.

On Linux, *note find_library(): d72. tries to run external programs
(‘/sbin/ldconfig’, ‘gcc’, ‘objdump’ and ‘ld’) to find the library file.
It returns the filename of the library file.

Note that if the output of these programs does not correspond to the
dynamic linker used by Python, the result of this function may be
misleading.

Changed in version 3.6: On Linux, the value of the environment variable
‘LD_LIBRARY_PATH’ is used when searching for libraries, if a library
cannot be found by any other means.

Here are some examples:

     >>> from ctypes.util import find_library
     >>> find_library("m")
     'libm.so.6'
     >>> find_library("c")
     'libc.so.6'
     >>> find_library("bz2")
     'libbz2.so.1.0'
     >>>

On macOS and Android, *note find_library(): d72. uses the system’s
standard naming schemes and paths to locate the library, and returns a
full pathname if successful:

     >>> from ctypes.util import find_library
     >>> find_library("c")
     '/usr/lib/libc.dylib'
     >>> find_library("m")
     '/usr/lib/libm.dylib'
     >>> find_library("bz2")
     '/usr/lib/libbz2.dylib'
     >>> find_library("AGL")
     '/System/Library/Frameworks/AGL.framework/AGL'
     >>>

On Windows, *note find_library(): d72. searches along the system search
path, and returns the full pathname, but since there is no predefined
naming scheme a call like ‘find_library("c")’ will fail and return
‘None’.

If wrapping a shared library with ‘ctypes’, it 'may' be better to
determine the shared library name at development time, and hardcode that
into the wrapper module instead of using *note find_library(): d72. to
locate the library at runtime.


File: python.info,  Node: Loading shared libraries,  Next: Foreign functions,  Prev: Finding shared libraries,  Up: ctypes reference

5.16.9.25 Loading shared libraries
..................................

There are several ways to load shared libraries into the Python process.
One way is to instantiate one of the following classes:

 -- Class: ctypes.CDLL (name, mode=DEFAULT_MODE, handle=None,
          use_errno=False, use_last_error=False, winmode=None)

     Instances of this class represent loaded shared libraries.
     Functions in these libraries use the standard C calling convention,
     and are assumed to return int.

     On Windows creating a ‘CDLL’ instance may fail even if the DLL name
     exists.  When a dependent DLL of the loaded DLL is not found, a
     *note OSError: 41a. error is raised with the message '“[WinError
     126] The specified module could not be found”.'  This error message
     does not contain the name of the missing DLL because the Windows
     API does not return this information making this error hard to
     diagnose.  To resolve this error and determine which DLL is not
     found, you need to find the list of dependent DLLs and determine
     which one is not found using Windows debugging and tracing tools.

     Changed in version 3.12: The 'name' parameter can now be a *note
     path-like object: 2a0.

See also
........

Microsoft DUMPBIN tool(1) – A tool to find DLL dependents.

 -- Class: ctypes.OleDLL (name, mode=DEFAULT_MODE, handle=None,
          use_errno=False, use_last_error=False, winmode=None)

     Instances of this class represent loaded shared libraries,
     functions in these libraries use the ‘stdcall’ calling convention,
     and are assumed to return the windows specific *note HRESULT: 3024.
     code.  ‘HRESULT’ values contain information specifying whether the
     function call failed or succeeded, together with additional error
     code.  If the return value signals a failure, an *note OSError:
     41a. is automatically raised.

     *note Availability: 1ef7.: Windows

     Changed in version 3.3: *note WindowsError: 1092. used to be
     raised, which is now an alias of *note OSError: 41a.

     Changed in version 3.12: The 'name' parameter can now be a *note
     path-like object: 2a0.

 -- Class: ctypes.WinDLL (name, mode=DEFAULT_MODE, handle=None,
          use_errno=False, use_last_error=False, winmode=None)

     Instances of this class represent loaded shared libraries,
     functions in these libraries use the ‘stdcall’ calling convention,
     and are assumed to return int by default.

     *note Availability: 1ef7.: Windows

     Changed in version 3.12: The 'name' parameter can now be a *note
     path-like object: 2a0.

The Python *note global interpreter lock: 148. is released before
calling any function exported by these libraries, and reacquired
afterwards.

 -- Class: ctypes.PyDLL (name, mode=DEFAULT_MODE, handle=None)

     Instances of this class behave like *note CDLL: 9f4. instances,
     except that the Python GIL is 'not' released during the function
     call, and after the function execution the Python error flag is
     checked.  If the error flag is set, a Python exception is raised.

     Thus, this is only useful to call Python C api functions directly.

     Changed in version 3.12: The 'name' parameter can now be a *note
     path-like object: 2a0.

All these classes can be instantiated by calling them with at least one
argument, the pathname of the shared library.  If you have an existing
handle to an already loaded shared library, it can be passed as the
‘handle’ named parameter, otherwise the underlying platform’s ‘dlopen()’
or ‘LoadLibrary()’ function is used to load the library into the
process, and to get a handle to it.

The 'mode' parameter can be used to specify how the library is loaded.
For details, consult the ‘dlopen(3)(2)’ manpage.  On Windows, 'mode' is
ignored.  On posix systems, RTLD_NOW is always added, and is not
configurable.

The 'use_errno' parameter, when set to true, enables a ctypes mechanism
that allows accessing the system *note errno: 57. error number in a safe
way.  ‘ctypes’ maintains a thread-local copy of the system’s ‘errno’
variable; if you call foreign functions created with ‘use_errno=True’
then the ‘errno’ value before the function call is swapped with the
ctypes private copy, the same happens immediately after the function
call.

The function *note ctypes.get_errno(): 3025. returns the value of the
ctypes private copy, and the function *note ctypes.set_errno(): 3026.
changes the ctypes private copy to a new value and returns the former
value.

The 'use_last_error' parameter, when set to true, enables the same
mechanism for the Windows error code which is managed by the *note
GetLastError(): 2ff8. and ‘SetLastError()’ Windows API functions; *note
ctypes.get_last_error(): 3027. and *note ctypes.set_last_error(): 3028.
are used to request and change the ctypes private copy of the windows
error code.

The 'winmode' parameter is used on Windows to specify how the library is
loaded (since 'mode' is ignored).  It takes any value that is valid for
the Win32 API ‘LoadLibraryEx’ flags parameter.  When omitted, the
default is to use the flags that result in the most secure DLL load,
which avoids issues such as DLL hijacking.  Passing the full path to the
DLL is the safest way to ensure the correct library and dependencies are
loaded.

Changed in version 3.8: Added 'winmode' parameter.

 -- Data: ctypes.RTLD_GLOBAL

     Flag to use as 'mode' parameter.  On platforms where this flag is
     not available, it is defined as the integer zero.

 -- Data: ctypes.RTLD_LOCAL

     Flag to use as 'mode' parameter.  On platforms where this is not
     available, it is the same as 'RTLD_GLOBAL'.

 -- Data: ctypes.DEFAULT_MODE

     The default mode which is used to load shared libraries.  On OSX
     10.3, this is 'RTLD_GLOBAL', otherwise it is the same as
     'RTLD_LOCAL'.

Instances of these classes have no public methods.  Functions exported
by the shared library can be accessed as attributes or by index.  Please
note that accessing the function through an attribute caches the result
and therefore accessing it repeatedly returns the same object each time.
On the other hand, accessing it through an index returns a new object
each time:

     >>> from ctypes import CDLL
     >>> libc = CDLL("libc.so.6")  # On Linux
     >>> libc.time == libc.time
     True
     >>> libc['time'] == libc['time']
     False

The following public attributes are available, their name starts with an
underscore to not clash with exported function names:

 -- Attribute: PyDLL._handle

     The system handle used to access the library.

 -- Attribute: PyDLL._name

     The name of the library passed in the constructor.

Shared libraries can also be loaded by using one of the prefabricated
objects, which are instances of the *note LibraryLoader: 302b. class,
either by calling the *note LoadLibrary(): 2fd1. method, or by
retrieving the library as attribute of the loader instance.

 -- Class: ctypes.LibraryLoader (dlltype)

     Class which loads shared libraries.  'dlltype' should be one of the
     *note CDLL: 9f4, *note PyDLL: 1887, *note WinDLL: 1886, or *note
     OleDLL: 1885. types.

     ‘__getattr__()’ has special behavior: It allows loading a shared
     library by accessing it as attribute of a library loader instance.
     The result is cached, so repeated attribute accesses return the
     same library each time.

      -- Method: LoadLibrary (name)

          Load a shared library into the process and return it.  This
          method always returns a new instance of the library.

These prefabricated library loaders are available:

 -- Data: ctypes.cdll

     Creates *note CDLL: 9f4. instances.

 -- Data: ctypes.windll

     Creates *note WinDLL: 1886. instances.

     *note Availability: 1ef7.: Windows

 -- Data: ctypes.oledll

     Creates *note OleDLL: 1885. instances.

     *note Availability: 1ef7.: Windows

 -- Data: ctypes.pydll

     Creates *note PyDLL: 1887. instances.

For accessing the C Python api directly, a ready-to-use Python shared
library object is available:

 -- Data: ctypes.pythonapi

     An instance of *note PyDLL: 1887. that exposes Python C API
     functions as attributes.  Note that all these functions are assumed
     to return C int, which is of course not always the truth, so you
     have to assign the correct ‘restype’ attribute to use these
     functions.

Loading a library through any of these objects raises an *note auditing
event: 1a15. ‘ctypes.dlopen’ with string argument ‘name’, the name used
to load the library.

Accessing a function on a loaded library raises an auditing event
‘ctypes.dlsym’ with arguments ‘library’ (the library object) and ‘name’
(the symbol’s name as a string or integer).

In cases when only the library handle is available rather than the
object, accessing a function raises an auditing event
‘ctypes.dlsym/handle’ with arguments ‘handle’ (the raw library handle)
and ‘name’.

   ---------- Footnotes ----------

   (1) https://docs.microsoft.com/cpp/build/reference/dependents

   (2) https://manpages.debian.org/dlopen(3)


File: python.info,  Node: Foreign functions,  Next: Function prototypes,  Prev: Loading shared libraries,  Up: ctypes reference

5.16.9.26 Foreign functions
...........................

As explained in the previous section, foreign functions can be accessed
as attributes of loaded shared libraries.  The function objects created
in this way by default accept any number of arguments, accept any ctypes
data instances as arguments, and return the default result type
specified by the library loader.

They are instances of a private local class ‘_FuncPtr’ (not exposed in
‘ctypes’) which inherits from the private *note _CFuncPtr: 302e. class:

     >>> import ctypes
     >>> lib = ctypes.CDLL(None)
     >>> issubclass(lib._FuncPtr, ctypes._CFuncPtr)
     True
     >>> lib._FuncPtr is ctypes._CFuncPtr
     False

 -- Class: ctypes._CFuncPtr

     Base class for C callable foreign functions.

     Instances of foreign functions are also C compatible data types;
     they represent C function pointers.

     This behavior can be customized by assigning to special attributes
     of the foreign function object.

      -- Attribute: restype

          Assign a ctypes type to specify the result type of the foreign
          function.  Use ‘None’ for void, a function not returning
          anything.

          It is possible to assign a callable Python object that is not
          a ctypes type, in this case the function is assumed to return
          a C int, and the callable will be called with this integer,
          allowing further processing or error checking.  Using this is
          deprecated, for more flexible post processing or error
          checking use a ctypes data type as ‘restype’ and assign a
          callable to the *note errcheck: 2ff9. attribute.

      -- Attribute: argtypes

          Assign a tuple of ctypes types to specify the argument types
          that the function accepts.  Functions using the ‘stdcall’
          calling convention can only be called with the same number of
          arguments as the length of this tuple; functions using the C
          calling convention accept additional, unspecified arguments as
          well.

          When a foreign function is called, each actual argument is
          passed to the *note from_param(): 2ff4. class method of the
          items in the *note argtypes: 1617. tuple, this method allows
          adapting the actual argument to an object that the foreign
          function accepts.  For example, a *note c_char_p: 17f6. item
          in the ‘argtypes’ tuple will convert a string passed as
          argument into a bytes object using ctypes conversion rules.

          New: It is now possible to put items in argtypes which are not
          ctypes types, but each item must have a *note from_param():
          2ff4. method which returns a value usable as argument
          (integer, string, ctypes instance).  This allows defining
          adapters that can adapt custom objects as function parameters.

      -- Attribute: errcheck

          Assign a Python function or another callable to this
          attribute.  The callable will be called with three or more
          arguments:

           -- Function: callable (result, func, arguments)

               'result' is what the foreign function returns, as
               specified by the ‘restype’ attribute.

               'func' is the foreign function object itself, this allows
               reusing the same callable object to check or post process
               the results of several functions.

               'arguments' is a tuple containing the parameters
               originally passed to the function call, this allows
               specializing the behavior on the arguments used.

          The object that this function returns will be returned from
          the foreign function call, but it can also check the result
          value and raise an exception if the foreign function call
          failed.

 -- Exception: ctypes.ArgumentError

     This exception is raised when a foreign function call cannot
     convert one of the passed arguments.

On Windows, when a foreign function call raises a system exception (for
example, due to an access violation), it will be captured and replaced
with a suitable Python exception.  Further, an auditing event
‘ctypes.set_exception’ with argument ‘code’ will be raised, allowing an
audit hook to replace the exception with its own.

Some ways to invoke foreign function calls may raise an auditing event
‘ctypes.call_function’ with arguments ‘function pointer’ and
‘arguments’.


File: python.info,  Node: Function prototypes,  Next: Utility functions,  Prev: Foreign functions,  Up: ctypes reference

5.16.9.27 Function prototypes
.............................

Foreign functions can also be created by instantiating function
prototypes.  Function prototypes are similar to function prototypes in
C; they describe a function (return type, argument types, calling
convention) without defining an implementation.  The factory functions
must be called with the desired result type and the argument types of
the function, and can be used as decorator factories, and as such, be
applied to functions through the ‘@wrapper’ syntax.  See *note Callback
functions: 3012. for examples.

 -- Function: ctypes.CFUNCTYPE (restype, *argtypes, use_errno=False,
          use_last_error=False)

     The returned function prototype creates functions that use the
     standard C calling convention.  The function will release the GIL
     during the call.  If 'use_errno' is set to true, the ctypes private
     copy of the system *note errno: 57. variable is exchanged with the
     real ‘errno’ value before and after the call; 'use_last_error' does
     the same for the Windows error code.

 -- Function: ctypes.WINFUNCTYPE (restype, *argtypes, use_errno=False,
          use_last_error=False)

     The returned function prototype creates functions that use the
     ‘stdcall’ calling convention.  The function will release the GIL
     during the call.  'use_errno' and 'use_last_error' have the same
     meaning as above.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.PYFUNCTYPE (restype, *argtypes)

     The returned function prototype creates functions that use the
     Python calling convention.  The function will 'not' release the GIL
     during the call.

Function prototypes created by these factory functions can be
instantiated in different ways, depending on the type and number of the
parameters in the call:

 -- Function: prototype (address)

     Returns a foreign function at the specified address which must be
     an integer.

 -- Function: prototype (callable)

     Create a C callable function (a callback function) from a Python
     'callable'.

 -- Function: prototype (func_spec[, paramflags])

     Returns a foreign function exported by a shared library.
     'func_spec' must be a 2-tuple ‘(name_or_ordinal, library)’.  The
     first item is the name of the exported function as string, or the
     ordinal of the exported function as small integer.  The second item
     is the shared library instance.

 -- Function: prototype (vtbl_index, name[, paramflags[, iid]])

     Returns a foreign function that will call a COM method.
     'vtbl_index' is the index into the virtual function table, a small
     non-negative integer.  'name' is name of the COM method.  'iid' is
     an optional pointer to the interface identifier which is used in
     extended error reporting.

     COM methods use a special calling convention: They require a
     pointer to the COM interface as first argument, in addition to
     those parameters that are specified in the ‘argtypes’ tuple.

The optional 'paramflags' parameter creates foreign function wrappers
with much more functionality than the features described above.

'paramflags' must be a tuple of the same length as *note argtypes: 1617.

Each item in this tuple contains further information about a parameter,
it must be a tuple containing one, two, or three items.

The first item is an integer containing a combination of direction flags
for the parameter:

     1

          Specifies an input parameter to the function.

     2

          Output parameter.  The foreign function fills in a value.

     4

          Input parameter which defaults to the integer zero.

The optional second item is the parameter name as string.  If this is
specified, the foreign function can be called with named parameters.

The optional third item is the default value for this parameter.

The following example demonstrates how to wrap the Windows ‘MessageBoxW’
function so that it supports default parameters and named arguments.
The C declaration from the windows header file is this:

     WINUSERAPI int WINAPI
     MessageBoxW(
         HWND hWnd,
         LPCWSTR lpText,
         LPCWSTR lpCaption,
         UINT uType);

Here is the wrapping with ‘ctypes’:

     >>> from ctypes import c_int, WINFUNCTYPE, windll
     >>> from ctypes.wintypes import HWND, LPCWSTR, UINT
     >>> prototype = WINFUNCTYPE(c_int, HWND, LPCWSTR, LPCWSTR, UINT)
     >>> paramflags = (1, "hwnd", 0), (1, "text", "Hi"), (1, "caption", "Hello from ctypes"), (1, "flags", 0)
     >>> MessageBox = prototype(("MessageBoxW", windll.user32), paramflags)

The ‘MessageBox’ foreign function can now be called in these ways:

     >>> MessageBox()
     >>> MessageBox(text="Spam, spam, spam")
     >>> MessageBox(flags=2, text="foo bar")

A second example demonstrates output parameters.  The win32
‘GetWindowRect’ function retrieves the dimensions of a specified window
by copying them into ‘RECT’ structure that the caller has to supply.
Here is the C declaration:

     WINUSERAPI BOOL WINAPI
     GetWindowRect(
          HWND hWnd,
          LPRECT lpRect);

Here is the wrapping with ‘ctypes’:

     >>> from ctypes import POINTER, WINFUNCTYPE, windll, WinError
     >>> from ctypes.wintypes import BOOL, HWND, RECT
     >>> prototype = WINFUNCTYPE(BOOL, HWND, POINTER(RECT))
     >>> paramflags = (1, "hwnd"), (2, "lprect")
     >>> GetWindowRect = prototype(("GetWindowRect", windll.user32), paramflags)
     >>>

Functions with output parameters will automatically return the output
parameter value if there is a single one, or a tuple containing the
output parameter values when there are more than one, so the
GetWindowRect function now returns a RECT instance, when called.

Output parameters can be combined with the *note errcheck: 2ff9.
protocol to do further output processing and error checking.  The win32
‘GetWindowRect’ api function returns a ‘BOOL’ to signal success or
failure, so this function could do the error checking, and raises an
exception when the api call failed:

     >>> def errcheck(result, func, args):
     ...     if not result:
     ...         raise WinError()
     ...     return args
     ...
     >>> GetWindowRect.errcheck = errcheck
     >>>

If the *note errcheck: 2ff9. function returns the argument tuple it
receives unchanged, ‘ctypes’ continues the normal processing it does on
the output parameters.  If you want to return a tuple of window
coordinates instead of a ‘RECT’ instance, you can retrieve the fields in
the function and return them instead, the normal processing will no
longer take place:

     >>> def errcheck(result, func, args):
     ...     if not result:
     ...         raise WinError()
     ...     rc = args[1]
     ...     return rc.left, rc.top, rc.bottom, rc.right
     ...
     >>> GetWindowRect.errcheck = errcheck
     >>>


File: python.info,  Node: Utility functions,  Next: Data types<2>,  Prev: Function prototypes,  Up: ctypes reference

5.16.9.28 Utility functions
...........................

 -- Function: ctypes.addressof (obj)

     Returns the address of the memory buffer as integer.  'obj' must be
     an instance of a ctypes type.

     Raises an *note auditing event: 1a15. ‘ctypes.addressof’ with
     argument ‘obj’.

 -- Function: ctypes.alignment (obj_or_type)

     Returns the alignment requirements of a ctypes type.  'obj_or_type'
     must be a ctypes type or instance.

 -- Function: ctypes.byref (obj[, offset])

     Returns a light-weight pointer to 'obj', which must be an instance
     of a ctypes type.  'offset' defaults to zero, and must be an
     integer that will be added to the internal pointer value.

     ‘byref(obj, offset)’ corresponds to this C code:

          (((char *)&obj) + offset)

     The returned object can only be used as a foreign function call
     parameter.  It behaves similar to ‘pointer(obj)’, but the
     construction is a lot faster.

 -- Function: ctypes.cast (obj, type)

     This function is similar to the cast operator in C. It returns a
     new instance of 'type' which points to the same memory block as
     'obj'.  'type' must be a pointer type, and 'obj' must be an object
     that can be interpreted as a pointer.

 -- Function: ctypes.create_string_buffer (init, size=None)

 -- Function: ctypes.create_string_buffer (size)

     This function creates a mutable character buffer.  The returned
     object is a ctypes array of *note c_char: 2fd9.

     If 'size' is given (and not ‘None’), it must be an *note int: 257.
     It specifies the size of the returned array.

     If the 'init' argument is given, it must be *note bytes: 1c2.  It
     is used to initialize the array items.  Bytes not initialized this
     way are set to zero (NUL).

     If 'size' is not given (or if it is ‘None’), the buffer is made one
     element larger than 'init', effectively adding a NUL terminator.

     If both arguments are given, 'size' must not be less than
     ‘len(init)’.

          Warning: If 'size' is equal to ‘len(init)’, a NUL terminator
          is not added.  Do not treat such a buffer as a C string.

     For example:

          >>> bytes(create_string_buffer(2))
          b'\x00\x00'
          >>> bytes(create_string_buffer(b'ab'))
          b'ab\x00'
          >>> bytes(create_string_buffer(b'ab', 2))
          b'ab'
          >>> bytes(create_string_buffer(b'ab', 4))
          b'ab\x00\x00'
          >>> bytes(create_string_buffer(b'abcdef', 2))
          Traceback (most recent call last):
             ...
          ValueError: byte string too long

     Raises an *note auditing event: 1a15. ‘ctypes.create_string_buffer’
     with arguments ‘init’, ‘size’.

 -- Function: ctypes.create_unicode_buffer (init, size=None)

 -- Function: ctypes.create_unicode_buffer (size)

     This function creates a mutable unicode character buffer.  The
     returned object is a ctypes array of *note c_wchar: 2fda.

     The function takes the same arguments as *note
     create_string_buffer(): 2feb. except 'init' must be a string and
     'size' counts *note c_wchar: 2fda.

     Raises an *note auditing event: 1a15.
     ‘ctypes.create_unicode_buffer’ with arguments ‘init’, ‘size’.

 -- Function: ctypes.DllCanUnloadNow ()

     This function is a hook which allows implementing in-process COM
     servers with ctypes.  It is called from the DllCanUnloadNow
     function that the _ctypes extension dll exports.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.DllGetClassObject ()

     This function is a hook which allows implementing in-process COM
     servers with ctypes.  It is called from the DllGetClassObject
     function that the ‘_ctypes’ extension dll exports.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.util.find_library (name)

     Try to find a library and return a pathname.  'name' is the library
     name without any prefix like ‘lib’, suffix like ‘.so’, ‘.dylib’ or
     version number (this is the form used for the posix linker option
     ‘-l’).  If no library can be found, returns ‘None’.

     The exact functionality is system dependent.

     See *note Finding shared libraries: 3020. for complete
     documentation.

 -- Function: ctypes.util.find_msvcrt ()

     Returns the filename of the VC runtime library used by Python, and
     by the extension modules.  If the name of the library cannot be
     determined, ‘None’ is returned.

     If you need to free memory, for example, allocated by an extension
     module with a call to the ‘free(void *)’, it is important that you
     use the function in the same library that allocated the memory.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.FormatError ([code])

     Returns a textual description of the error code 'code'.  If no
     error code is specified, the last error code is used by calling the
     Windows api function GetLastError.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.GetLastError ()

     Returns the last error code set by Windows in the calling thread.
     This function calls the Windows ‘GetLastError()’ function directly,
     it does not return the ctypes-private copy of the error code.

     *note Availability: 1ef7.: Windows

 -- Function: ctypes.get_errno ()

     Returns the current value of the ctypes-private copy of the system
     *note errno: 57. variable in the calling thread.

     Raises an *note auditing event: 1a15. ‘ctypes.get_errno’ with no
     arguments.

 -- Function: ctypes.get_last_error ()

     Returns the current value of the ctypes-private copy of the system
     ‘LastError’ variable in the calling thread.

     *note Availability: 1ef7.: Windows

     Raises an *note auditing event: 1a15. ‘ctypes.get_last_error’ with
     no arguments.

 -- Function: ctypes.memmove (dst, src, count)

     Same as the standard C memmove library function: copies 'count'
     bytes from 'src' to 'dst'.  'dst' and 'src' must be integers or
     ctypes instances that can be converted to pointers.

 -- Function: ctypes.memset (dst, c, count)

     Same as the standard C memset library function: fills the memory
     block at address 'dst' with 'count' bytes of value 'c'.  'dst' must
     be an integer specifying an address, or a ctypes instance.

 -- Function: ctypes.POINTER (type, /)

     Create and return a new ctypes pointer type.  Pointer types are
     cached and reused internally, so calling this function repeatedly
     is cheap.  'type' must be a ctypes type.

 -- Function: ctypes.pointer (obj, /)

     Create a new pointer instance, pointing to 'obj'.  The returned
     object is of the type ‘POINTER(type(obj))’.

     Note: If you just want to pass a pointer to an object to a foreign
     function call, you should use ‘byref(obj)’ which is much faster.

 -- Function: ctypes.resize (obj, size)

     This function resizes the internal memory buffer of 'obj', which
     must be an instance of a ctypes type.  It is not possible to make
     the buffer smaller than the native size of the objects type, as
     given by ‘sizeof(type(obj))’, but it is possible to enlarge the
     buffer.

 -- Function: ctypes.set_errno (value)

     Set the current value of the ctypes-private copy of the system
     *note errno: 57. variable in the calling thread to 'value' and
     return the previous value.

     Raises an *note auditing event: 1a15. ‘ctypes.set_errno’ with
     argument ‘errno’.

 -- Function: ctypes.set_last_error (value)

     Sets the current value of the ctypes-private copy of the system
     ‘LastError’ variable in the calling thread to 'value' and return
     the previous value.

     *note Availability: 1ef7.: Windows

     Raises an *note auditing event: 1a15. ‘ctypes.set_last_error’ with
     argument ‘error’.

 -- Function: ctypes.sizeof (obj_or_type)

     Returns the size in bytes of a ctypes type or instance memory
     buffer.  Does the same as the C ‘sizeof’ operator.

 -- Function: ctypes.string_at (ptr, size=-1)

     Return the byte string at 'void *ptr'.  If 'size' is specified, it
     is used as size, otherwise the string is assumed to be
     zero-terminated.

     Raises an *note auditing event: 1a15. ‘ctypes.string_at’ with
     arguments ‘ptr’, ‘size’.

 -- Function: ctypes.WinError (code=None, descr=None)

     This function is probably the worst-named thing in ctypes.  It
     creates an instance of *note OSError: 41a.  If 'code' is not
     specified, ‘GetLastError’ is called to determine the error code.
     If 'descr' is not specified, *note FormatError(): 303a. is called
     to get a textual description of the error.

     *note Availability: 1ef7.: Windows

     Changed in version 3.3: An instance of *note WindowsError: 1092.
     used to be created, which is now an alias of *note OSError: 41a.

 -- Function: ctypes.wstring_at (ptr, size=-1)

     Return the wide-character string at 'void *ptr'.  If 'size' is
     specified, it is used as the number of characters of the string,
     otherwise the string is assumed to be zero-terminated.

     Raises an *note auditing event: 1a15. ‘ctypes.wstring_at’ with
     arguments ‘ptr’, ‘size’.


File: python.info,  Node: Data types<2>,  Next: Fundamental data types<2>,  Prev: Utility functions,  Up: ctypes reference

5.16.9.29 Data types
....................

 -- Class: ctypes._CData

     This non-public class is the common base class of all ctypes data
     types.  Among other things, all ctypes type instances contain a
     memory block that hold C compatible data; the address of the memory
     block is returned by the *note addressof(): 3035. helper function.
     Another instance variable is exposed as *note _objects: 3044.; this
     contains other Python objects that need to be kept alive in case
     the memory block contains pointers.

     Common methods of ctypes data types, these are all class methods
     (to be exact, they are methods of the *note metaclass: 2136.):

      -- Method: from_buffer (source[, offset])

          This method returns a ctypes instance that shares the buffer
          of the 'source' object.  The 'source' object must support the
          writeable buffer interface.  The optional 'offset' parameter
          specifies an offset into the source buffer in bytes; the
          default is zero.  If the source buffer is not large enough a
          *note ValueError: 202. is raised.

          Raises an *note auditing event: 1a15. ‘ctypes.cdata/buffer’
          with arguments ‘pointer’, ‘size’, ‘offset’.

      -- Method: from_buffer_copy (source[, offset])

          This method creates a ctypes instance, copying the buffer from
          the 'source' object buffer which must be readable.  The
          optional 'offset' parameter specifies an offset into the
          source buffer in bytes; the default is zero.  If the source
          buffer is not large enough a *note ValueError: 202. is raised.

          Raises an *note auditing event: 1a15. ‘ctypes.cdata/buffer’
          with arguments ‘pointer’, ‘size’, ‘offset’.

      -- Method: from_address (address)

          This method returns a ctypes type instance using the memory
          specified by 'address' which must be an integer.

          This method, and others that indirectly call this method,
          raises an *note auditing event: 1a15. ‘ctypes.cdata’ with
          argument ‘address’.

      -- Method: from_param (obj)

          This method adapts 'obj' to a ctypes type.  It is called with
          the actual object used in a foreign function call when the
          type is present in the foreign function’s *note argtypes:
          1617. tuple; it must return an object that can be used as a
          function call parameter.

          All ctypes data types have a default implementation of this
          classmethod that normally returns 'obj' if that is an instance
          of the type.  Some types accept other objects as well.

      -- Method: in_dll (library, name)

          This method returns a ctypes type instance exported by a
          shared library.  'name' is the name of the symbol that exports
          the data, 'library' is the loaded shared library.

     Common instance variables of ctypes data types:

      -- Attribute: _b_base_

          Sometimes ctypes data instances do not own the memory block
          they contain, instead they share part of the memory block of a
          base object.  The *note _b_base_: 3048. read-only member is
          the root ctypes object that owns the memory block.

      -- Attribute: _b_needsfree_

          This read-only variable is true when the ctypes data instance
          has allocated the memory block itself, false otherwise.

      -- Attribute: _objects

          This member is either ‘None’ or a dictionary containing Python
          objects that need to be kept alive so that the memory block
          contents is kept valid.  This object is only exposed for
          debugging; never modify the contents of this dictionary.


File: python.info,  Node: Fundamental data types<2>,  Next: Structured data types,  Prev: Data types<2>,  Up: ctypes reference

5.16.9.30 Fundamental data types
................................

 -- Class: ctypes._SimpleCData

     This non-public class is the base class of all fundamental ctypes
     data types.  It is mentioned here because it contains the common
     attributes of the fundamental ctypes data types.  ‘_SimpleCData’ is
     a subclass of *note _CData: 3043, so it inherits their methods and
     attributes.  ctypes data types that are not and do not contain
     pointers can now be pickled.

     Instances have a single attribute:

      -- Attribute: value

          This attribute contains the actual value of the instance.  For
          integer and pointer types, it is an integer, for character
          types, it is a single character bytes object or string, for
          character pointer types it is a Python bytes object or string.

          When the ‘value’ attribute is retrieved from a ctypes
          instance, usually a new object is returned each time.
          ‘ctypes’ does 'not' implement original object return, always a
          new object is constructed.  The same is true for all other
          ctypes object instances.

Fundamental data types, when returned as foreign function call results,
or, for example, by retrieving structure field members or array items,
are transparently converted to native Python types.  In other words, if
a foreign function has a *note restype: 2ff7. of *note c_char_p: 17f6,
you will always receive a Python bytes object, 'not' a ‘c_char_p’
instance.

Subclasses of fundamental data types do 'not' inherit this behavior.
So, if a foreign functions ‘restype’ is a subclass of *note c_void_p:
17f8, you will receive an instance of this subclass from the function
call.  Of course, you can get the value of the pointer by accessing the
‘value’ attribute.

These are the fundamental ctypes data types:

 -- Class: ctypes.c_byte

     Represents the C signed char datatype, and interprets the value as
     small integer.  The constructor accepts an optional integer
     initializer; no overflow checking is done.

 -- Class: ctypes.c_char

     Represents the C char datatype, and interprets the value as a
     single character.  The constructor accepts an optional string
     initializer, the length of the string must be exactly one
     character.

 -- Class: ctypes.c_char_p

     Represents the C char* datatype when it points to a zero-terminated
     string.  For a general character pointer that may also point to
     binary data, ‘POINTER(c_char)’ must be used.  The constructor
     accepts an integer address, or a bytes object.

 -- Class: ctypes.c_double

     Represents the C double datatype.  The constructor accepts an
     optional float initializer.

 -- Class: ctypes.c_longdouble

     Represents the C long double datatype.  The constructor accepts an
     optional float initializer.  On platforms where ‘sizeof(long
     double) == sizeof(double)’ it is an alias to *note c_double: 1a5e.

 -- Class: ctypes.c_float

     Represents the C float datatype.  The constructor accepts an
     optional float initializer.

 -- Class: ctypes.c_int

     Represents the C signed int datatype.  The constructor accepts an
     optional integer initializer; no overflow checking is done.  On
     platforms where ‘sizeof(int) == sizeof(long)’ it is an alias to
     *note c_long: 2fce.

 -- Class: ctypes.c_int8

     Represents the C 8-bit signed int datatype.  It is an alias for
     *note c_byte: 1883.

 -- Class: ctypes.c_int16

     Represents the C 16-bit signed int datatype.  Usually an alias for
     *note c_short: 2fdb.

 -- Class: ctypes.c_int32

     Represents the C 32-bit signed int datatype.  Usually an alias for
     *note c_int: 2fcd.

 -- Class: ctypes.c_int64

     Represents the C 64-bit signed int datatype.  Usually an alias for
     *note c_longlong: 2fe7.

 -- Class: ctypes.c_long

     Represents the C signed long datatype.  The constructor accepts an
     optional integer initializer; no overflow checking is done.

 -- Class: ctypes.c_longlong

     Represents the C signed long long datatype.  The constructor
     accepts an optional integer initializer; no overflow checking is
     done.

 -- Class: ctypes.c_short

     Represents the C signed short datatype.  The constructor accepts an
     optional integer initializer; no overflow checking is done.

 -- Class: ctypes.c_size_t

     Represents the C ‘size_t’ datatype.

 -- Class: ctypes.c_ssize_t

     Represents the C ‘ssize_t’ datatype.

     Added in version 3.2.

 -- Class: ctypes.c_time_t

     Represents the C ‘time_t’ datatype.

     Added in version 3.12.

 -- Class: ctypes.c_ubyte

     Represents the C unsigned char datatype, it interprets the value as
     small integer.  The constructor accepts an optional integer
     initializer; no overflow checking is done.

 -- Class: ctypes.c_uint

     Represents the C unsigned int datatype.  The constructor accepts an
     optional integer initializer; no overflow checking is done.  On
     platforms where ‘sizeof(int) == sizeof(long)’ it is an alias for
     *note c_ulong: 2fe6.

 -- Class: ctypes.c_uint8

     Represents the C 8-bit unsigned int datatype.  It is an alias for
     *note c_ubyte: 1884.

 -- Class: ctypes.c_uint16

     Represents the C 16-bit unsigned int datatype.  Usually an alias
     for *note c_ushort: 2fdc.

 -- Class: ctypes.c_uint32

     Represents the C 32-bit unsigned int datatype.  Usually an alias
     for *note c_uint: 2fe1.

 -- Class: ctypes.c_uint64

     Represents the C 64-bit unsigned int datatype.  Usually an alias
     for *note c_ulonglong: 2fe8.

 -- Class: ctypes.c_ulong

     Represents the C unsigned long datatype.  The constructor accepts
     an optional integer initializer; no overflow checking is done.

 -- Class: ctypes.c_ulonglong

     Represents the C unsigned long long datatype.  The constructor
     accepts an optional integer initializer; no overflow checking is
     done.

 -- Class: ctypes.c_ushort

     Represents the C unsigned short datatype.  The constructor accepts
     an optional integer initializer; no overflow checking is done.

 -- Class: ctypes.c_void_p

     Represents the C void* type.  The value is represented as integer.
     The constructor accepts an optional integer initializer.

 -- Class: ctypes.c_wchar

     Represents the C ‘wchar_t’ datatype, and interprets the value as a
     single character unicode string.  The constructor accepts an
     optional string initializer, the length of the string must be
     exactly one character.

 -- Class: ctypes.c_wchar_p

     Represents the C wchar_t* datatype, which must be a pointer to a
     zero-terminated wide character string.  The constructor accepts an
     integer address, or a string.

 -- Class: ctypes.c_bool

     Represent the C bool datatype (more accurately, _Bool from C99).
     Its value can be ‘True’ or ‘False’, and the constructor accepts any
     object that has a truth value.

 -- Class: ctypes.HRESULT

     Represents a ‘HRESULT’ value, which contains success or error
     information for a function or method call.

     *note Availability: 1ef7.: Windows

 -- Class: ctypes.py_object

     Represents the C *note PyObject: 33a.* datatype.  Calling this
     without an argument creates a ‘NULL’ PyObject* pointer.

The ‘ctypes.wintypes’ module provides quite some other Windows specific
data types, for example ‘HWND’, ‘WPARAM’, or ‘DWORD’.  Some useful
structures like ‘MSG’ or ‘RECT’ are also defined.


File: python.info,  Node: Structured data types,  Next: Arrays and pointers,  Prev: Fundamental data types<2>,  Up: ctypes reference

5.16.9.31 Structured data types
...............................

 -- Class: ctypes.Union (*args, **kw)

     Abstract base class for unions in native byte order.

 -- Class: ctypes.BigEndianUnion (*args, **kw)

     Abstract base class for unions in 'big endian' byte order.

     Added in version 3.11.

 -- Class: ctypes.LittleEndianUnion (*args, **kw)

     Abstract base class for unions in 'little endian' byte order.

     Added in version 3.11.

 -- Class: ctypes.BigEndianStructure (*args, **kw)

     Abstract base class for structures in 'big endian' byte order.

 -- Class: ctypes.LittleEndianStructure (*args, **kw)

     Abstract base class for structures in 'little endian' byte order.

Structures and unions with non-native byte order cannot contain pointer
type fields, or any other data types containing pointer type fields.

 -- Class: ctypes.Structure (*args, **kw)

     Abstract base class for structures in 'native' byte order.

     Concrete structure and union types must be created by subclassing
     one of these types, and at least define a *note _fields_: 2fff.
     class variable.  ‘ctypes’ will create *note descriptor: 1677.s
     which allow reading and writing the fields by direct attribute
     accesses.  These are the

      -- Attribute: _fields_

          A sequence defining the structure fields.  The items must be
          2-tuples or 3-tuples.  The first item is the name of the
          field, the second item specifies the type of the field; it can
          be any ctypes data type.

          For integer type fields like *note c_int: 2fcd, a third
          optional item can be given.  It must be a small positive
          integer defining the bit width of the field.

          Field names must be unique within one structure or union.
          This is not checked, only one field can be accessed when names
          are repeated.

          It is possible to define the *note _fields_: 2fff. class
          variable 'after' the class statement that defines the
          Structure subclass, this allows creating data types that
          directly or indirectly reference themselves:

               class List(Structure):
                   pass
               List._fields_ = [("pnext", POINTER(List)),
                                ...
                               ]

          The *note _fields_: 2fff. class variable must, however, be
          defined before the type is first used (an instance is created,
          *note sizeof(): 303d. is called on it, and so on).  Later
          assignments to the ‘_fields_’ class variable will raise an
          AttributeError.

          It is possible to define sub-subclasses of structure types,
          they inherit the fields of the base class plus the *note
          _fields_: 2fff. defined in the sub-subclass, if any.

      -- Attribute: _pack_

          An optional small integer that allows overriding the alignment
          of structure fields in the instance.  *note _pack_: 3002. must
          already be defined when *note _fields_: 2fff. is assigned,
          otherwise it will have no effect.  Setting this attribute to 0
          is the same as not setting it at all.

      -- Attribute: _align_

          An optional small integer that allows overriding the alignment
          of the structure when being packed or unpacked to/from memory.
          Setting this attribute to 0 is the same as not setting it at
          all.

          Added in version 3.13.

      -- Attribute: _anonymous_

          An optional sequence that lists the names of unnamed
          (anonymous) fields.  *note _anonymous_: 3050. must be already
          defined when *note _fields_: 2fff. is assigned, otherwise it
          will have no effect.

          The fields listed in this variable must be structure or union
          type fields.  ‘ctypes’ will create descriptors in the
          structure type that allows accessing the nested fields
          directly, without the need to create the structure or union
          field.

          Here is an example type (Windows):

               class _U(Union):
                   _fields_ = [("lptdesc", POINTER(TYPEDESC)),
                               ("lpadesc", POINTER(ARRAYDESC)),
                               ("hreftype", HREFTYPE)]

               class TYPEDESC(Structure):
                   _anonymous_ = ("u",)
                   _fields_ = [("u", _U),
                               ("vt", VARTYPE)]

          The ‘TYPEDESC’ structure describes a COM data type, the ‘vt’
          field specifies which one of the union fields is valid.  Since
          the ‘u’ field is defined as anonymous field, it is now
          possible to access the members directly off the TYPEDESC
          instance.  ‘td.lptdesc’ and ‘td.u.lptdesc’ are equivalent, but
          the former is faster since it does not need to create a
          temporary union instance:

               td = TYPEDESC()
               td.vt = VT_PTR
               td.lptdesc = POINTER(some_type)
               td.u.lptdesc = POINTER(some_type)

     It is possible to define sub-subclasses of structures, they inherit
     the fields of the base class.  If the subclass definition has a
     separate *note _fields_: 2fff. variable, the fields specified in
     this are appended to the fields of the base class.

     Structure and union constructors accept both positional and keyword
     arguments.  Positional arguments are used to initialize member
     fields in the same order as they are appear in *note _fields_:
     2fff.  Keyword arguments in the constructor are interpreted as
     attribute assignments, so they will initialize ‘_fields_’ with the
     same name, or create new attributes for names not present in
     ‘_fields_’.


File: python.info,  Node: Arrays and pointers,  Prev: Structured data types,  Up: ctypes reference

5.16.9.32 Arrays and pointers
.............................

 -- Class: ctypes.Array (*args)

     Abstract base class for arrays.

     The recommended way to create concrete array types is by
     multiplying any ‘ctypes’ data type with a non-negative integer.
     Alternatively, you can subclass this type and define *note
     _length_: 3053. and *note _type_: 3054. class variables.  Array
     elements can be read and written using standard subscript and slice
     accesses; for slice reads, the resulting object is 'not' itself an
     ‘Array’.

      -- Attribute: _length_

          A positive integer specifying the number of elements in the
          array.  Out-of-range subscripts result in an *note IndexError:
          1585.  Will be returned by *note len(): 631.

      -- Attribute: _type_

          Specifies the type of each element in the array.

     Array subclass constructors accept positional arguments, used to
     initialize the elements in order.

 -- Function: ctypes.ARRAY (type, length)

     Create an array.  Equivalent to ‘type * length’, where 'type' is a
     ‘ctypes’ data type and 'length' an integer.

     This function is *note soft deprecated: 209. in favor of
     multiplication.  There are no plans to remove it.

 -- Class: ctypes._Pointer

     Private, abstract base class for pointers.

     Concrete pointer types are created by calling *note POINTER():
     17f5. with the type that will be pointed to; this is done
     automatically by *note pointer(): 17f4.

     If a pointer points to an array, its elements can be read and
     written using standard subscript and slice accesses.  Pointer
     objects have no size, so *note len(): 631. will raise *note
     TypeError: 2c3.  Negative subscripts will read from the memory
     'before' the pointer (as in C), and out-of-range subscripts will
     probably crash with an access violation (if you’re lucky).

      -- Attribute: _type_

          Specifies the type pointed to.

      -- Attribute: contents

          Returns the object to which to pointer points.  Assigning to
          this attribute changes the pointer to point to the assigned
          object.


File: python.info,  Node: Command-line interface libraries,  Next: Concurrent Execution,  Prev: Generic Operating System Services,  Up: The Python Standard Library

5.17 Command-line interface libraries
=====================================

The modules described in this chapter assist with implementing command
line and terminal interfaces for applications.

Here’s an overview:

* Menu:

* argparse — Parser for command-line options, arguments and subcommands: argparse — Parser for command-line options arguments and subcommands.
* optparse — Parser for command line options::
* getpass — Portable password input::
* fileinput — Iterate over lines from multiple input streams::
* curses — Terminal handling for character-cell displays::
* curses.textpad — Text input widget for curses programs: curses textpad — Text input widget for curses programs.
* curses.ascii — Utilities for ASCII characters: curses ascii — Utilities for ASCII characters.
* curses.panel — A panel stack extension for curses: curses panel — A panel stack extension for curses.
* cmd — Support for line-oriented command interpreters::


File: python.info,  Node: argparse — Parser for command-line options arguments and subcommands,  Next: optparse — Parser for command line options,  Up: Command-line interface libraries

5.17.1 ‘argparse’ — Parser for command-line options, arguments and subcommands
------------------------------------------------------------------------------

Added in version 3.2.

'Source code:' Lib/argparse.py(1)

     Note: While ‘argparse’ is the default recommended standard library
     module for implementing basic command line applications, authors
     with more exacting requirements for exactly how their command line
     applications behave may find it doesn’t provide the necessary level
     of control.  Refer to *note Choosing an argument parsing library:
     305c. for alternatives to consider when ‘argparse’ doesn’t support
     behaviors that the application requires (such as entirely disabling
     support for interspersed options and positional arguments, or
     accepting option parameter values that start with ‘-’ even when
     they correspond to another defined option).

__________________________________________________________________

Tutorial
........

This page contains the API reference information.  For a more gentle
introduction to Python command-line parsing, have a look at the *note
argparse tutorial: 305d.

The ‘argparse’ module makes it easy to write user-friendly command-line
interfaces.  The program defines what arguments it requires, and
‘argparse’ will figure out how to parse those out of *note sys.argv:
12ab.  The ‘argparse’ module also automatically generates help and usage
messages.  The module will also issue errors when users give the program
invalid arguments.

The ‘argparse’ module’s support for command-line interfaces is built
around an instance of *note argparse.ArgumentParser: 53c.  It is a
container for argument specifications and has options that apply to the
parser as whole:

     parser = argparse.ArgumentParser(
                         prog='ProgramName',
                         description='What the program does',
                         epilog='Text at the bottom of help')

The *note ArgumentParser.add_argument(): 19e. method attaches individual
argument specifications to the parser.  It supports positional
arguments, options that accept values, and on/off flags:

     parser.add_argument('filename')           # positional argument
     parser.add_argument('-c', '--count')      # option that takes a value
     parser.add_argument('-v', '--verbose',
                         action='store_true')  # on/off flag

The *note ArgumentParser.parse_args(): 305e. method runs the parser and
places the extracted data in a *note argparse.Namespace: 305f. object:

     args = parser.parse_args()
     print(args.filename, args.count, args.verbose)

     Note: If you’re looking for a guide about how to upgrade *note
     optparse: a0. code to ‘argparse’, see *note Upgrading Optparse
     Code: 11f2.

* Menu:

* ArgumentParser objects::
* The add_argument() method: The add_argument method.
* The parse_args() method: The parse_args method.
* Other utilities::
* Exceptions: Exceptions<9>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/argparse.py


File: python.info,  Node: ArgumentParser objects,  Next: The add_argument method,  Up: argparse — Parser for command-line options arguments and subcommands

5.17.1.1 ArgumentParser objects
...............................

 -- Class: argparse.ArgumentParser (prog=None, usage=None,
          description=None, epilog=None, parents=[],
          formatter_class=argparse.HelpFormatter, prefix_chars='-',
          fromfile_prefix_chars=None, argument_default=None,
          conflict_handler='error', add_help=True, allow_abbrev=True,
          exit_on_error=True)

     Create a new ‘ArgumentParser’ object.  All parameters should be
     passed as keyword arguments.  Each parameter has its own more
     detailed description below, but in short they are:

        * *note prog: 3061. - The name of the program (default:
          ‘os.path.basename(sys.argv[0])’)

        * *note usage: 3062. - The string describing the program usage
          (default: generated from arguments added to parser)

        * *note description: 3063. - Text to display before the argument
          help (by default, no text)

        * *note epilog: 3064. - Text to display after the argument help
          (by default, no text)

        * *note parents: 3065. - A list of ‘ArgumentParser’ objects
          whose arguments should also be included

        * *note formatter_class: 3066. - A class for customizing the
          help output

        * *note prefix_chars: 3067. - The set of characters that prefix
          optional arguments (default: ‘-‘)

        * *note fromfile_prefix_chars: 3068. - The set of characters
          that prefix files from which additional arguments should be
          read (default: ‘None’)

        * *note argument_default: 3069. - The global default value for
          arguments (default: ‘None’)

        * *note conflict_handler: 306a. - The strategy for resolving
          conflicting optionals (usually unnecessary)

        * *note add_help: 306b. - Add a ‘-h/--help’ option to the parser
          (default: ‘True’)

        * *note allow_abbrev: dee. - Allows long options to be
          abbreviated if the abbreviation is unambiguous.  (default:
          ‘True’)

        * *note exit_on_error: 306c. - Determines whether or not
          ‘ArgumentParser’ exits with error info when an error occurs.
          (default: ‘True’)

     Changed in version 3.5: 'allow_abbrev' parameter was added.

     Changed in version 3.8: In previous versions, 'allow_abbrev' also
     disabled grouping of short flags such as ‘-vv’ to mean ‘-v -v’.

     Changed in version 3.9: 'exit_on_error' parameter was added.

The following sections describe how each of these are used.

* Menu:

* prog::
* usage::
* description::
* epilog::
* parents::
* formatter_class::
* prefix_chars::
* fromfile_prefix_chars::
* argument_default::
* allow_abbrev::
* conflict_handler::
* add_help::
* exit_on_error::


File: python.info,  Node: prog,  Next: usage,  Up: ArgumentParser objects

5.17.1.2 prog
.............

By default, *note ArgumentParser: 53c. calculates the name of the
program to display in help messages depending on the way the Python
interpreter was run:

   * The *note base name: 29a1. of ‘sys.argv[0]’ if a file was passed as
     argument.

   * The Python interpreter name followed by ‘sys.argv[0]’ if a
     directory or a zipfile was passed as argument.

   * The Python interpreter name followed by ‘-m’ followed by the module
     or package name if the *note -m: 5e4. option was used.

This default is almost always desirable because it will make the help
messages match the string that was used to invoke the program on the
command line.  However, to change this default behavior, another value
can be supplied using the ‘prog=’ argument to *note ArgumentParser:
53c.:

     >>> parser = argparse.ArgumentParser(prog='myprogram')
     >>> parser.print_help()
     usage: myprogram [-h]

     options:
      -h, --help  show this help message and exit

Note that the program name, whether determined from ‘sys.argv[0]’ or
from the ‘prog=’ argument, is available to help messages using the
‘%(prog)s’ format specifier.

     >>> parser = argparse.ArgumentParser(prog='myprogram')
     >>> parser.add_argument('--foo', help='foo of the %(prog)s program')
     >>> parser.print_help()
     usage: myprogram [-h] [--foo FOO]

     options:
      -h, --help  show this help message and exit
      --foo FOO   foo of the myprogram program


File: python.info,  Node: usage,  Next: description,  Prev: prog,  Up: ArgumentParser objects

5.17.1.3 usage
..............

By default, *note ArgumentParser: 53c. calculates the usage message from
the arguments it contains.  The default message can be overridden with
the ‘usage=’ keyword argument:

     >>> parser = argparse.ArgumentParser(prog='PROG', usage='%(prog)s [options]')
     >>> parser.add_argument('--foo', nargs='?', help='foo help')
     >>> parser.add_argument('bar', nargs='+', help='bar help')
     >>> parser.print_help()
     usage: PROG [options]

     positional arguments:
      bar          bar help

     options:
      -h, --help   show this help message and exit
      --foo [FOO]  foo help

The ‘%(prog)s’ format specifier is available to fill in the program name
in your usage messages.


File: python.info,  Node: description,  Next: epilog,  Prev: usage,  Up: ArgumentParser objects

5.17.1.4 description
....................

Most calls to the *note ArgumentParser: 53c. constructor will use the
‘description=’ keyword argument.  This argument gives a brief
description of what the program does and how it works.  In help
messages, the description is displayed between the command-line usage
string and the help messages for the various arguments.

By default, the description will be line-wrapped so that it fits within
the given space.  To change this behavior, see the *note
formatter_class: 3066. argument.


File: python.info,  Node: epilog,  Next: parents,  Prev: description,  Up: ArgumentParser objects

5.17.1.5 epilog
...............

Some programs like to display additional description of the program
after the description of the arguments.  Such text can be specified
using the ‘epilog=’ argument to *note ArgumentParser: 53c.:

     >>> parser = argparse.ArgumentParser(
     ...     description='A foo that bars',
     ...     epilog="And that's how you'd foo a bar")
     >>> parser.print_help()
     usage: argparse.py [-h]

     A foo that bars

     options:
      -h, --help  show this help message and exit

     And that's how you'd foo a bar

As with the *note description: 3063. argument, the ‘epilog=’ text is by
default line-wrapped, but this behavior can be adjusted with the *note
formatter_class: 3066. argument to *note ArgumentParser: 53c.


File: python.info,  Node: parents,  Next: formatter_class,  Prev: epilog,  Up: ArgumentParser objects

5.17.1.6 parents
................

Sometimes, several parsers share a common set of arguments.  Rather than
repeating the definitions of these arguments, a single parser with all
the shared arguments and passed to ‘parents=’ argument to *note
ArgumentParser: 53c. can be used.  The ‘parents=’ argument takes a list
of ‘ArgumentParser’ objects, collects all the positional and optional
actions from them, and adds these actions to the ‘ArgumentParser’ object
being constructed:

     >>> parent_parser = argparse.ArgumentParser(add_help=False)
     >>> parent_parser.add_argument('--parent', type=int)

     >>> foo_parser = argparse.ArgumentParser(parents=[parent_parser])
     >>> foo_parser.add_argument('foo')
     >>> foo_parser.parse_args(['--parent', '2', 'XXX'])
     Namespace(foo='XXX', parent=2)

     >>> bar_parser = argparse.ArgumentParser(parents=[parent_parser])
     >>> bar_parser.add_argument('--bar')
     >>> bar_parser.parse_args(['--bar', 'YYY'])
     Namespace(bar='YYY', parent=None)

Note that most parent parsers will specify ‘add_help=False’.  Otherwise,
the *note ArgumentParser: 53c. will see two ‘-h/--help’ options (one in
the parent and one in the child) and raise an error.

     Note: You must fully initialize the parsers before passing them via
     ‘parents=’.  If you change the parent parsers after the child
     parser, those changes will not be reflected in the child.


File: python.info,  Node: formatter_class,  Next: prefix_chars,  Prev: parents,  Up: ArgumentParser objects

5.17.1.7 formatter_class
........................

*note ArgumentParser: 53c. objects allow the help formatting to be
customized by specifying an alternate formatting class.  Currently,
there are four such classes:

 -- Class: argparse.RawDescriptionHelpFormatter
 -- Class: argparse.RawTextHelpFormatter
 -- Class: argparse.ArgumentDefaultsHelpFormatter
 -- Class: argparse.MetavarTypeHelpFormatter

*note RawDescriptionHelpFormatter: 3070. and *note RawTextHelpFormatter:
3071. give more control over how textual descriptions are displayed.  By
default, *note ArgumentParser: 53c. objects line-wrap the *note
description: 3063. and *note epilog: 3064. texts in command-line help
messages:

     >>> parser = argparse.ArgumentParser(
     ...     prog='PROG',
     ...     description='''this description
     ...         was indented weird
     ...             but that is okay''',
     ...     epilog='''
     ...             likewise for this epilog whose whitespace will
     ...         be cleaned up and whose words will be wrapped
     ...         across a couple lines''')
     >>> parser.print_help()
     usage: PROG [-h]

     this description was indented weird but that is okay

     options:
      -h, --help  show this help message and exit

     likewise for this epilog whose whitespace will be cleaned up and whose words
     will be wrapped across a couple lines

Passing *note RawDescriptionHelpFormatter: 3070. as ‘formatter_class=’
indicates that *note description: 3063. and *note epilog: 3064. are
already correctly formatted and should not be line-wrapped:

     >>> parser = argparse.ArgumentParser(
     ...     prog='PROG',
     ...     formatter_class=argparse.RawDescriptionHelpFormatter,
     ...     description=textwrap.dedent('''\
     ...         Please do not mess up this text!
     ...         --------------------------------
     ...             I have indented it
     ...             exactly the way
     ...             I want it
     ...         '''))
     >>> parser.print_help()
     usage: PROG [-h]

     Please do not mess up this text!
     --------------------------------
        I have indented it
        exactly the way
        I want it

     options:
      -h, --help  show this help message and exit

*note RawTextHelpFormatter: 3071. maintains whitespace for all sorts of
help text, including argument descriptions.  However, multiple newlines
are replaced with one.  If you wish to preserve multiple blank lines,
add spaces between the newlines.

*note ArgumentDefaultsHelpFormatter: 19f6. automatically adds
information about default values to each of the argument help messages:

     >>> parser = argparse.ArgumentParser(
     ...     prog='PROG',
     ...     formatter_class=argparse.ArgumentDefaultsHelpFormatter)
     >>> parser.add_argument('--foo', type=int, default=42, help='FOO!')
     >>> parser.add_argument('bar', nargs='*', default=[1, 2, 3], help='BAR!')
     >>> parser.print_help()
     usage: PROG [-h] [--foo FOO] [bar ...]

     positional arguments:
      bar         BAR! (default: [1, 2, 3])

     options:
      -h, --help  show this help message and exit
      --foo FOO   FOO! (default: 42)

*note MetavarTypeHelpFormatter: 3072. uses the name of the *note type:
3073. argument for each argument as the display name for its values
(rather than using the *note dest: 3074. as the regular formatter does):

     >>> parser = argparse.ArgumentParser(
     ...     prog='PROG',
     ...     formatter_class=argparse.MetavarTypeHelpFormatter)
     >>> parser.add_argument('--foo', type=int)
     >>> parser.add_argument('bar', type=float)
     >>> parser.print_help()
     usage: PROG [-h] [--foo int] float

     positional arguments:
       float

     options:
       -h, --help  show this help message and exit
       --foo int


File: python.info,  Node: prefix_chars,  Next: fromfile_prefix_chars,  Prev: formatter_class,  Up: ArgumentParser objects

5.17.1.8 prefix_chars
.....................

Most command-line options will use ‘-’ as the prefix, e.g.  ‘-f/--foo’.
Parsers that need to support different or additional prefix characters,
e.g.  for options like ‘+f’ or ‘/foo’, may specify them using the
‘prefix_chars=’ argument to the *note ArgumentParser: 53c. constructor:

     >>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='-+')
     >>> parser.add_argument('+f')
     >>> parser.add_argument('++bar')
     >>> parser.parse_args('+f X ++bar Y'.split())
     Namespace(bar='Y', f='X')

The ‘prefix_chars=’ argument defaults to ‘'-'’.  Supplying a set of
characters that does not include ‘-’ will cause ‘-f/--foo’ options to be
disallowed.


File: python.info,  Node: fromfile_prefix_chars,  Next: argument_default,  Prev: prefix_chars,  Up: ArgumentParser objects

5.17.1.9 fromfile_prefix_chars
..............................

Sometimes, when dealing with a particularly long argument list, it may
make sense to keep the list of arguments in a file rather than typing it
out at the command line.  If the ‘fromfile_prefix_chars=’ argument is
given to the *note ArgumentParser: 53c. constructor, then arguments that
start with any of the specified characters will be treated as files, and
will be replaced by the arguments they contain.  For example:

     >>> with open('args.txt', 'w', encoding=sys.getfilesystemencoding()) as fp:
     ...     fp.write('-f\nbar')
     ...
     >>> parser = argparse.ArgumentParser(fromfile_prefix_chars='@')
     >>> parser.add_argument('-f')
     >>> parser.parse_args(['-f', 'foo', '@args.txt'])
     Namespace(f='bar')

Arguments read from a file must be one per line by default (but see also
*note convert_arg_line_to_args(): 3075.) and are treated as if they were
in the same place as the original file referencing argument on the
command line.  So in the example above, the expression ‘['-f', 'foo',
'@args.txt']’ is considered equivalent to the expression ‘['-f', 'foo',
'-f', 'bar']’.

     Note: Empty lines are treated as empty strings (‘''’), which are
     allowed as values but not as arguments.  Empty lines that are read
     as arguments will result in an “unrecognized arguments” error.

*note ArgumentParser: 53c. uses *note filesystem encoding and error
handler: 53e. to read the file containing arguments.

The ‘fromfile_prefix_chars=’ argument defaults to ‘None’, meaning that
arguments will never be treated as file references.

Changed in version 3.12: *note ArgumentParser: 53c. changed encoding and
errors to read arguments files from default (e.g.  *note
locale.getpreferredencoding(False): 53d. and ‘"strict"’) to the *note
filesystem encoding and error handler: 53e.  Arguments file should be
encoded in UTF-8 instead of ANSI Codepage on Windows.


File: python.info,  Node: argument_default,  Next: allow_abbrev,  Prev: fromfile_prefix_chars,  Up: ArgumentParser objects

5.17.1.10 argument_default
..........................

Generally, argument defaults are specified either by passing a default
to *note add_argument(): 19e. or by calling the *note set_defaults():
3076. methods with a specific set of name-value pairs.  Sometimes
however, it may be useful to specify a single parser-wide default for
arguments.  This can be accomplished by passing the ‘argument_default=’
keyword argument to *note ArgumentParser: 53c.  For example, to globally
suppress attribute creation on *note parse_args(): 305e. calls, we
supply ‘argument_default=SUPPRESS’:

     >>> parser = argparse.ArgumentParser(argument_default=argparse.SUPPRESS)
     >>> parser.add_argument('--foo')
     >>> parser.add_argument('bar', nargs='?')
     >>> parser.parse_args(['--foo', '1', 'BAR'])
     Namespace(bar='BAR', foo='1')
     >>> parser.parse_args([])
     Namespace()


File: python.info,  Node: allow_abbrev,  Next: conflict_handler,  Prev: argument_default,  Up: ArgumentParser objects

5.17.1.11 allow_abbrev
......................

Normally, when you pass an argument list to the *note parse_args():
305e. method of an *note ArgumentParser: 53c, it *note recognizes
abbreviations: ded. of long options.

This feature can be disabled by setting ‘allow_abbrev’ to ‘False’:

     >>> parser = argparse.ArgumentParser(prog='PROG', allow_abbrev=False)
     >>> parser.add_argument('--foobar', action='store_true')
     >>> parser.add_argument('--foonley', action='store_false')
     >>> parser.parse_args(['--foon'])
     usage: PROG [-h] [--foobar] [--foonley]
     PROG: error: unrecognized arguments: --foon

Added in version 3.5.


File: python.info,  Node: conflict_handler,  Next: add_help,  Prev: allow_abbrev,  Up: ArgumentParser objects

5.17.1.12 conflict_handler
..........................

*note ArgumentParser: 53c. objects do not allow two actions with the
same option string.  By default, ‘ArgumentParser’ objects raise an
exception if an attempt is made to create an argument with an option
string that is already in use:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-f', '--foo', help='old foo help')
     >>> parser.add_argument('--foo', help='new foo help')
     Traceback (most recent call last):
      ..
     ArgumentError: argument --foo: conflicting option string(s): --foo

Sometimes (e.g.  when using *note parents: 3065.) it may be useful to
simply override any older arguments with the same option string.  To get
this behavior, the value ‘'resolve'’ can be supplied to the
‘conflict_handler=’ argument of *note ArgumentParser: 53c.:

     >>> parser = argparse.ArgumentParser(prog='PROG', conflict_handler='resolve')
     >>> parser.add_argument('-f', '--foo', help='old foo help')
     >>> parser.add_argument('--foo', help='new foo help')
     >>> parser.print_help()
     usage: PROG [-h] [-f FOO] [--foo FOO]

     options:
      -h, --help  show this help message and exit
      -f FOO      old foo help
      --foo FOO   new foo help

Note that *note ArgumentParser: 53c. objects only remove an action if
all of its option strings are overridden.  So, in the example above, the
old ‘-f/--foo’ action is retained as the ‘-f’ action, because only the
‘--foo’ option string was overridden.


File: python.info,  Node: add_help,  Next: exit_on_error,  Prev: conflict_handler,  Up: ArgumentParser objects

5.17.1.13 add_help
..................

By default, *note ArgumentParser: 53c. objects add an option which
simply displays the parser’s help message.  If ‘-h’ or ‘--help’ is
supplied at the command line, the ‘ArgumentParser’ help will be printed.

Occasionally, it may be useful to disable the addition of this help
option.  This can be achieved by passing ‘False’ as the ‘add_help=’
argument to *note ArgumentParser: 53c.:

     >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
     >>> parser.add_argument('--foo', help='foo help')
     >>> parser.print_help()
     usage: PROG [--foo FOO]

     options:
      --foo FOO  foo help

The help option is typically ‘-h/--help’.  The exception to this is if
the ‘prefix_chars=’ is specified and does not include ‘-’, in which case
‘-h’ and ‘--help’ are not valid options.  In this case, the first
character in ‘prefix_chars’ is used to prefix the help options:

     >>> parser = argparse.ArgumentParser(prog='PROG', prefix_chars='+/')
     >>> parser.print_help()
     usage: PROG [+h]

     options:
       +h, ++help  show this help message and exit


File: python.info,  Node: exit_on_error,  Prev: add_help,  Up: ArgumentParser objects

5.17.1.14 exit_on_error
.......................

Normally, when you pass an invalid argument list to the *note
parse_args(): 305e. method of an *note ArgumentParser: 53c, it will
print a 'message' to *note sys.stderr: 943. and exit with a status code
of 2.

If the user would like to catch errors manually, the feature can be
enabled by setting ‘exit_on_error’ to ‘False’:

     >>> parser = argparse.ArgumentParser(exit_on_error=False)
     >>> parser.add_argument('--integers', type=int)
     _StoreAction(option_strings=['--integers'], dest='integers', nargs=None, const=None, default=None, type=<class 'int'>, choices=None, help=None, metavar=None)
     >>> try:
     ...     parser.parse_args('--integers a'.split())
     ... except argparse.ArgumentError:
     ...     print('Catching an argumentError')
     ...
     Catching an argumentError

Added in version 3.9.


File: python.info,  Node: The add_argument method,  Next: The parse_args method,  Prev: ArgumentParser objects,  Up: argparse — Parser for command-line options arguments and subcommands

5.17.1.15 The add_argument() method
...................................

 -- Method: ArgumentParser.add_argument (name or flags..., *[, action][,
          nargs][, const][, default][, type][, choices][, required][,
          help][, metavar][, dest][, deprecated])

     Define how a single command-line argument should be parsed.  Each
     parameter has its own more detailed description below, but in short
     they are:

        * *note name or flags: 3079. - Either a name or a list of option
          strings, e.g.  ‘'foo'’ or ‘'-f', '--foo'’.

        * *note action: 307a. - The basic type of action to be taken
          when this argument is encountered at the command line.

        * *note nargs: 16b0. - The number of command-line arguments that
          should be consumed.

        * *note const: 307b. - A constant value required by some *note
          action: 307a. and *note nargs: 16b0. selections.

        * *note default: 307c. - The value produced if the argument is
          absent from the command line and if it is absent from the
          namespace object.

        * *note type: 3073. - The type to which the command-line
          argument should be converted.

        * *note choices: 16ad. - A sequence of the allowable values for
          the argument.

        * *note required: 307d. - Whether or not the command-line option
          may be omitted (optionals only).

        * *note help: 307e. - A brief description of what the argument
          does.

        * *note metavar: 307f. - A name for the argument in usage
          messages.

        * *note dest: 3074. - The name of the attribute to be added to
          the object returned by *note parse_args(): 305e.

        * *note deprecated: 3080. - Whether or not use of the argument
          is deprecated.

     The method returns an *note Action: 1932. object representing the
     argument.

The following sections describe how each of these are used.

* Menu:

* name or flags::
* action::
* nargs::
* const::
* default::
* type::
* choices::
* required::
* help::
* metavar::
* dest::
* deprecated::
* Action classes::


File: python.info,  Node: name or flags,  Next: action,  Up: The add_argument method

5.17.1.16 name or flags
.......................

The *note add_argument(): 19e. method must know whether an optional
argument, like ‘-f’ or ‘--foo’, or a positional argument, like a list of
filenames, is expected.  The first arguments passed to ‘add_argument()’
must therefore be either a series of flags, or a simple argument name.

For example, an optional argument could be created like:

     >>> parser.add_argument('-f', '--foo')

while a positional argument could be created like:

     >>> parser.add_argument('bar')

When *note parse_args(): 305e. is called, optional arguments will be
identified by the ‘-’ prefix, and the remaining arguments will be
assumed to be positional:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-f', '--foo')
     >>> parser.add_argument('bar')
     >>> parser.parse_args(['BAR'])
     Namespace(bar='BAR', foo=None)
     >>> parser.parse_args(['BAR', '--foo', 'FOO'])
     Namespace(bar='BAR', foo='FOO')
     >>> parser.parse_args(['--foo', 'FOO'])
     usage: PROG [-h] [-f FOO] bar
     PROG: error: the following arguments are required: bar


File: python.info,  Node: action,  Next: nargs,  Prev: name or flags,  Up: The add_argument method

5.17.1.17 action
................

*note ArgumentParser: 53c. objects associate command-line arguments with
actions.  These actions can do just about anything with the command-line
arguments associated with them, though most actions simply add an
attribute to the object returned by *note parse_args(): 305e.  The
‘action’ keyword argument specifies how the command-line arguments
should be handled.  The supplied actions are:

   * ‘'store'’ - This just stores the argument’s value.  This is the
     default action.

   * ‘'store_const'’ - This stores the value specified by the *note
     const: 307b. keyword argument; note that the *note const: 307b.
     keyword argument defaults to ‘None’.  The ‘'store_const'’ action is
     most commonly used with optional arguments that specify some sort
     of flag.  For example:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', action='store_const', const=42)
          >>> parser.parse_args(['--foo'])
          Namespace(foo=42)

   * ‘'store_true'’ and ‘'store_false'’ - These are special cases of
     ‘'store_const'’ that respectively store the values ‘True’ and
     ‘False’ with default values of ‘False’ and ‘True’:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', action='store_true')
          >>> parser.add_argument('--bar', action='store_false')
          >>> parser.add_argument('--baz', action='store_false')
          >>> parser.parse_args('--foo --bar'.split())
          Namespace(foo=True, bar=False, baz=True)

   * ‘'append'’ - This appends each argument value to a list.  It is
     useful for allowing an option to be specified multiple times.  If
     the default value is a non-empty list, the parsed value will start
     with the default list’s elements and any values from the command
     line will be appended after those default values.  Example usage:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', action='append', default=['0'])
          >>> parser.parse_args('--foo 1 --foo 2'.split())
          Namespace(foo=['0', '1', '2'])

   * ‘'append_const'’ - This appends the value specified by the *note
     const: 307b. keyword argument to a list; note that the *note const:
     307b. keyword argument defaults to ‘None’.  The ‘'append_const'’
     action is typically useful when multiple arguments need to store
     constants to the same list.  For example:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--str', dest='types', action='append_const', const=str)
          >>> parser.add_argument('--int', dest='types', action='append_const', const=int)
          >>> parser.parse_args('--str --int'.split())
          Namespace(types=[<class 'str'>, <class 'int'>])

   * ‘'extend'’ - This appends each item from a multi-value argument to
     a list.  The ‘'extend'’ action is typically used with the *note
     nargs: 16b0. keyword argument value ‘'+'’ or ‘'*'’.  Note that when
     *note nargs: 16b0. is ‘None’ (the default) or ‘'?'’, each character
     of the argument string will be appended to the list.  Example
     usage:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument("--foo", action="extend", nargs="+", type=str)
          >>> parser.parse_args(["--foo", "f1", "--foo", "f2", "f3", "f4"])
          Namespace(foo=['f1', 'f2', 'f3', 'f4'])

     Added in version 3.8.

   * ‘'count'’ - This counts the number of times an argument occurs.
     For example, this is useful for increasing verbosity levels:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--verbose', '-v', action='count', default=0)
          >>> parser.parse_args(['-vvv'])
          Namespace(verbose=3)

     Note, the 'default' will be ‘None’ unless explicitly set to '0'.

   * ‘'help'’ - This prints a complete help message for all the options
     in the current parser and then exits.  By default a help action is
     automatically added to the parser.  See *note ArgumentParser: 53c.
     for details of how the output is created.

   * ‘'version'’ - This expects a ‘version=’ keyword argument in the
     *note add_argument(): 19e. call, and prints version information and
     exits when invoked:

          >>> import argparse
          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> parser.add_argument('--version', action='version', version='%(prog)s 2.0')
          >>> parser.parse_args(['--version'])
          PROG 2.0

You may also specify an arbitrary action by passing an *note Action:
1932. subclass (e.g.  *note BooleanOptionalAction: 1996.) or other
object that implements the same interface.  Only actions that consume
command-line arguments (e.g.  ‘'store'’, ‘'append'’, ‘'extend'’, or
custom actions with non-zero ‘nargs’) can be used with positional
arguments.

The recommended way to create a custom action is to extend *note Action:
1932, overriding the ‘__call__()’ method and optionally the ‘__init__()’
and ‘format_usage()’ methods.  You can also register custom actions
using the *note register(): 3083. method and reference them by their
registered name.

An example of a custom action:

     >>> class FooAction(argparse.Action):
     ...     def __init__(self, option_strings, dest, nargs=None, **kwargs):
     ...         if nargs is not None:
     ...             raise ValueError("nargs not allowed")
     ...         super().__init__(option_strings, dest, **kwargs)
     ...     def __call__(self, parser, namespace, values, option_string=None):
     ...         print('%r %r %r' % (namespace, values, option_string))
     ...         setattr(namespace, self.dest, values)
     ...
     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', action=FooAction)
     >>> parser.add_argument('bar', action=FooAction)
     >>> args = parser.parse_args('1 --foo 2'.split())
     Namespace(bar=None, foo=None) '1' None
     Namespace(bar='1', foo=None) '2' '--foo'
     >>> args
     Namespace(bar='1', foo='2')

For more details, see *note Action: 1932.


File: python.info,  Node: nargs,  Next: const,  Prev: action,  Up: The add_argument method

5.17.1.18 nargs
...............

*note ArgumentParser: 53c. objects usually associate a single
command-line argument with a single action to be taken.  The ‘nargs’
keyword argument associates a different number of command-line arguments
with a single action.  See also *note Specifying ambiguous arguments:
3085.  The supported values are:

   * ‘N’ (an integer).  ‘N’ arguments from the command line will be
     gathered together into a list.  For example:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', nargs=2)
          >>> parser.add_argument('bar', nargs=1)
          >>> parser.parse_args('c --foo a b'.split())
          Namespace(bar=['c'], foo=['a', 'b'])

     Note that ‘nargs=1’ produces a list of one item.  This is different
     from the default, in which the item is produced by itself.

   * ‘'?'’.  One argument will be consumed from the command line if
     possible, and produced as a single item.  If no command-line
     argument is present, the value from *note default: 307c. will be
     produced.  Note that for optional arguments, there is an additional
     case - the option string is present but not followed by a
     command-line argument.  In this case the value from *note const:
     307b. will be produced.  Some examples to illustrate this:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', nargs='?', const='c', default='d')
          >>> parser.add_argument('bar', nargs='?', default='d')
          >>> parser.parse_args(['XX', '--foo', 'YY'])
          Namespace(bar='XX', foo='YY')
          >>> parser.parse_args(['XX', '--foo'])
          Namespace(bar='XX', foo='c')
          >>> parser.parse_args([])
          Namespace(bar='d', foo='d')

     One of the more common uses of ‘nargs='?'’ is to allow optional
     input and output files:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('infile', nargs='?', type=argparse.FileType('r'),
          ...                     default=sys.stdin)
          >>> parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'),
          ...                     default=sys.stdout)
          >>> parser.parse_args(['input.txt', 'output.txt'])
          Namespace(infile=<_io.TextIOWrapper name='input.txt' encoding='UTF-8'>,
                    outfile=<_io.TextIOWrapper name='output.txt' encoding='UTF-8'>)
          >>> parser.parse_args([])
          Namespace(infile=<_io.TextIOWrapper name='<stdin>' encoding='UTF-8'>,
                    outfile=<_io.TextIOWrapper name='<stdout>' encoding='UTF-8'>)

   * ‘'*'’.  All command-line arguments present are gathered into a
     list.  Note that it generally doesn’t make much sense to have more
     than one positional argument with ‘nargs='*'’, but multiple
     optional arguments with ‘nargs='*'’ is possible.  For example:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', nargs='*')
          >>> parser.add_argument('--bar', nargs='*')
          >>> parser.add_argument('baz', nargs='*')
          >>> parser.parse_args('a b --foo x y --bar 1 2'.split())
          Namespace(bar=['1', '2'], baz=['a', 'b'], foo=['x', 'y'])

   * ‘'+'’.  Just like ‘'*'’, all command-line arguments present are
     gathered into a list.  Additionally, an error message will be
     generated if there wasn’t at least one command-line argument
     present.  For example:

          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> parser.add_argument('foo', nargs='+')
          >>> parser.parse_args(['a', 'b'])
          Namespace(foo=['a', 'b'])
          >>> parser.parse_args([])
          usage: PROG [-h] foo [foo ...]
          PROG: error: the following arguments are required: foo

If the ‘nargs’ keyword argument is not provided, the number of arguments
consumed is determined by the *note action: 307a.  Generally this means
a single command-line argument will be consumed and a single item (not a
list) will be produced.  Actions that do not consume command-line
arguments (e.g.  ‘'store_const'’) set ‘nargs=0’.


File: python.info,  Node: const,  Next: default,  Prev: nargs,  Up: The add_argument method

5.17.1.19 const
...............

The ‘const’ argument of *note add_argument(): 19e. is used to hold
constant values that are not read from the command line but are required
for the various *note ArgumentParser: 53c. actions.  The two most common
uses of it are:

   * When *note add_argument(): 19e. is called with
     ‘action='store_const'’ or ‘action='append_const'’.  These actions
     add the ‘const’ value to one of the attributes of the object
     returned by *note parse_args(): 305e.  See the *note action: 307a.
     description for examples.  If ‘const’ is not provided to
     ‘add_argument()’, it will receive a default value of ‘None’.

   * When *note add_argument(): 19e. is called with option strings (like
     ‘-f’ or ‘--foo’) and ‘nargs='?'’.  This creates an optional
     argument that can be followed by zero or one command-line
     arguments.  When parsing the command line, if the option string is
     encountered with no command-line argument following it, the value
     from ‘const’ will be used.  See the *note nargs: 16b0. description
     for examples.

Changed in version 3.11: ‘const=None’ by default, including when
‘action='append_const'’ or ‘action='store_const'’.


File: python.info,  Node: default,  Next: type,  Prev: const,  Up: The add_argument method

5.17.1.20 default
.................

All optional arguments and some positional arguments may be omitted at
the command line.  The ‘default’ keyword argument of *note
add_argument(): 19e, whose value defaults to ‘None’, specifies what
value should be used if the command-line argument is not present.  For
optional arguments, the ‘default’ value is used when the option string
was not present at the command line:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', default=42)
     >>> parser.parse_args(['--foo', '2'])
     Namespace(foo='2')
     >>> parser.parse_args([])
     Namespace(foo=42)

If the target namespace already has an attribute set, the action
'default' will not overwrite it:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', default=42)
     >>> parser.parse_args([], namespace=argparse.Namespace(foo=101))
     Namespace(foo=101)

If the ‘default’ value is a string, the parser parses the value as if it
were a command-line argument.  In particular, the parser applies any
*note type: 3073. conversion argument, if provided, before setting the
attribute on the *note Namespace: 305f. return value.  Otherwise, the
parser uses the value as is:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--length', default='10', type=int)
     >>> parser.add_argument('--width', default=10.5, type=int)
     >>> parser.parse_args()
     Namespace(length=10, width=10.5)

For positional arguments with *note nargs: 16b0. equal to ‘?’ or ‘*’,
the ‘default’ value is used when no command-line argument was present:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('foo', nargs='?', default=42)
     >>> parser.parse_args(['a'])
     Namespace(foo='a')
     >>> parser.parse_args([])
     Namespace(foo=42)

For *note required: 307d. arguments, the ‘default’ value is ignored.
For example, this applies to positional arguments with *note nargs:
16b0. values other than ‘?’ or ‘*’, or optional arguments marked as
‘required=True’.

Providing ‘default=argparse.SUPPRESS’ causes no attribute to be added if
the command-line argument was not present:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', default=argparse.SUPPRESS)
     >>> parser.parse_args([])
     Namespace()
     >>> parser.parse_args(['--foo', '1'])
     Namespace(foo='1')


File: python.info,  Node: type,  Next: choices,  Prev: default,  Up: The add_argument method

5.17.1.21 type
..............

By default, the parser reads command-line arguments in as simple
strings.  However, quite often the command-line string should instead be
interpreted as another type, such as a *note float: 2f7. or *note int:
257.  The ‘type’ keyword for *note add_argument(): 19e. allows any
necessary type-checking and type conversions to be performed.

If the *note type: 3073. keyword is used with the *note default: 307c.
keyword, the type converter is only applied if the default is a string.

The argument to ‘type’ can be a callable that accepts a single string or
the name of a registered type (see *note register(): 3083.) If the
function raises *note ArgumentTypeError: 3089, *note TypeError: 2c3, or
*note ValueError: 202, the exception is caught and a nicely formatted
error message is displayed.  Other exception types are not handled.

Common built-in types and functions can be used as type converters:

     import argparse
     import pathlib

     parser = argparse.ArgumentParser()
     parser.add_argument('count', type=int)
     parser.add_argument('distance', type=float)
     parser.add_argument('street', type=ascii)
     parser.add_argument('code_point', type=ord)
     parser.add_argument('dest_file', type=argparse.FileType('w', encoding='latin-1'))
     parser.add_argument('datapath', type=pathlib.Path)

User defined functions can be used as well:

     >>> def hyphenated(string):
     ...     return '-'.join([word[:4] for word in string.casefold().split()])
     ...
     >>> parser = argparse.ArgumentParser()
     >>> _ = parser.add_argument('short_title', type=hyphenated)
     >>> parser.parse_args(['"The Tale of Two Cities"'])
     Namespace(short_title='"the-tale-of-two-citi')

The *note bool(): 46b. function is not recommended as a type converter.
All it does is convert empty strings to ‘False’ and non-empty strings to
‘True’.  This is usually not what is desired:

     >>> parser = argparse.ArgumentParser()
     >>> _ = parser.add_argument('--verbose', type=bool)
     >>> parser.parse_args(['--verbose', 'False'])
     Namespace(verbose=True)

See *note BooleanOptionalAction: 1996. or ‘action='store_true'’ for
common alternatives.

In general, the ‘type’ keyword is a convenience that should only be used
for simple conversions that can only raise one of the three supported
exceptions.  Anything with more interesting error-handling or resource
management should be done downstream after the arguments are parsed.

For example, JSON or YAML conversions have complex error cases that
require better reporting than can be given by the ‘type’ keyword.  A
*note JSONDecodeError: e53. would not be well formatted and a *note
FileNotFoundError: 42e. exception would not be handled at all.

Even *note FileType: f52. has its limitations for use with the ‘type’
keyword.  If one argument uses ‘FileType’ and then a subsequent argument
fails, an error is reported but the file is not automatically closed.
In this case, it would be better to wait until after the parser has run
and then use the *note with: 5d5.-statement to manage the files.

For type checkers that simply check against a fixed set of values,
consider using the *note choices: 16ad. keyword instead.


File: python.info,  Node: choices,  Next: required,  Prev: type,  Up: The add_argument method

5.17.1.22 choices
.................

Some command-line arguments should be selected from a restricted set of
values.  These can be handled by passing a sequence object as the
'choices' keyword argument to *note add_argument(): 19e.  When the
command line is parsed, argument values will be checked, and an error
message will be displayed if the argument was not one of the acceptable
values:

     >>> parser = argparse.ArgumentParser(prog='game.py')
     >>> parser.add_argument('move', choices=['rock', 'paper', 'scissors'])
     >>> parser.parse_args(['rock'])
     Namespace(move='rock')
     >>> parser.parse_args(['fire'])
     usage: game.py [-h] {rock,paper,scissors}
     game.py: error: argument move: invalid choice: 'fire' (choose from 'rock',
     'paper', 'scissors')

Any sequence can be passed as the 'choices' value, so *note list: 614.
objects, *note tuple: 373. objects, and custom sequences are all
supported.

Use of *note enum.Enum: 633. is not recommended because it is difficult
to control its appearance in usage, help, and error messages.

Note that 'choices' are checked after any *note type: 3073. conversions
have been performed, so objects in 'choices' should match the *note
type: 3073. specified.  This can make 'choices' appear unfamiliar in
usage, help, or error messages.

To keep 'choices' user-friendly, consider a custom type wrapper that
converts and formats values, or omit *note type: 3073. and handle
conversion in your application code.

Formatted choices override the default 'metavar' which is normally
derived from 'dest'.  This is usually what you want because the user
never sees the 'dest' parameter.  If this display isn’t desirable
(perhaps because there are many choices), just specify an explicit *note
metavar: 307f.


File: python.info,  Node: required,  Next: help,  Prev: choices,  Up: The add_argument method

5.17.1.23 required
..................

In general, the ‘argparse’ module assumes that flags like ‘-f’ and
‘--bar’ indicate 'optional' arguments, which can always be omitted at
the command line.  To make an option 'required', ‘True’ can be specified
for the ‘required=’ keyword argument to *note add_argument(): 19e.:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', required=True)
     >>> parser.parse_args(['--foo', 'BAR'])
     Namespace(foo='BAR')
     >>> parser.parse_args([])
     usage: [-h] --foo FOO
     : error: the following arguments are required: --foo

As the example shows, if an option is marked as ‘required’, *note
parse_args(): 305e. will report an error if that option is not present
at the command line.

     Note: Required options are generally considered bad form because
     users expect 'options' to be 'optional', and thus they should be
     avoided when possible.


File: python.info,  Node: help,  Next: metavar,  Prev: required,  Up: The add_argument method

5.17.1.24 help
..............

The ‘help’ value is a string containing a brief description of the
argument.  When a user requests help (usually by using ‘-h’ or ‘--help’
at the command line), these ‘help’ descriptions will be displayed with
each argument.

The ‘help’ strings can include various format specifiers to avoid
repetition of things like the program name or the argument *note
default: 307c.  The available specifiers include the program name,
‘%(prog)s’ and most keyword arguments to *note add_argument(): 19e, e.g.
‘%(default)s’, ‘%(type)s’, etc.:

     >>> parser = argparse.ArgumentParser(prog='frobble')
     >>> parser.add_argument('bar', nargs='?', type=int, default=42,
     ...                     help='the bar to %(prog)s (default: %(default)s)')
     >>> parser.print_help()
     usage: frobble [-h] [bar]

     positional arguments:
      bar     the bar to frobble (default: 42)

     options:
      -h, --help  show this help message and exit

As the help string supports %-formatting, if you want a literal ‘%’ to
appear in the help string, you must escape it as ‘%%’.

‘argparse’ supports silencing the help entry for certain options, by
setting the ‘help’ value to ‘argparse.SUPPRESS’:

     >>> parser = argparse.ArgumentParser(prog='frobble')
     >>> parser.add_argument('--foo', help=argparse.SUPPRESS)
     >>> parser.print_help()
     usage: frobble [-h]

     options:
       -h, --help  show this help message and exit


File: python.info,  Node: metavar,  Next: dest,  Prev: help,  Up: The add_argument method

5.17.1.25 metavar
.................

When *note ArgumentParser: 53c. generates help messages, it needs some
way to refer to each expected argument.  By default, ‘ArgumentParser’
objects use the *note dest: 3074. value as the “name” of each object.
By default, for positional argument actions, the *note dest: 3074. value
is used directly, and for optional argument actions, the *note dest:
3074. value is uppercased.  So, a single positional argument with
‘dest='bar'’ will be referred to as ‘bar’.  A single optional argument
‘--foo’ that should be followed by a single command-line argument will
be referred to as ‘FOO’.  An example:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo')
     >>> parser.add_argument('bar')
     >>> parser.parse_args('X --foo Y'.split())
     Namespace(bar='X', foo='Y')
     >>> parser.print_help()
     usage:  [-h] [--foo FOO] bar

     positional arguments:
      bar

     options:
      -h, --help  show this help message and exit
      --foo FOO

An alternative name can be specified with ‘metavar’:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', metavar='YYY')
     >>> parser.add_argument('bar', metavar='XXX')
     >>> parser.parse_args('X --foo Y'.split())
     Namespace(bar='X', foo='Y')
     >>> parser.print_help()
     usage:  [-h] [--foo YYY] XXX

     positional arguments:
      XXX

     options:
      -h, --help  show this help message and exit
      --foo YYY

Note that ‘metavar’ only changes the 'displayed' name - the name of the
attribute on the *note parse_args(): 305e. object is still determined by
the *note dest: 3074. value.

Different values of ‘nargs’ may cause the metavar to be used multiple
times.  Providing a tuple to ‘metavar’ specifies a different display for
each of the arguments:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-x', nargs=2)
     >>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))
     >>> parser.print_help()
     usage: PROG [-h] [-x X X] [--foo bar baz]

     options:
      -h, --help     show this help message and exit
      -x X X
      --foo bar baz


File: python.info,  Node: dest,  Next: deprecated,  Prev: metavar,  Up: The add_argument method

5.17.1.26 dest
..............

Most *note ArgumentParser: 53c. actions add some value as an attribute
of the object returned by *note parse_args(): 305e.  The name of this
attribute is determined by the ‘dest’ keyword argument of *note
add_argument(): 19e.  For positional argument actions, ‘dest’ is
normally supplied as the first argument to ‘add_argument()’:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('bar')
     >>> parser.parse_args(['XXX'])
     Namespace(bar='XXX')

For optional argument actions, the value of ‘dest’ is normally inferred
from the option strings.  *note ArgumentParser: 53c. generates the value
of ‘dest’ by taking the first long option string and stripping away the
initial ‘--’ string.  If no long option strings were supplied, ‘dest’
will be derived from the first short option string by stripping the
initial ‘-’ character.  Any internal ‘-’ characters will be converted to
‘_’ characters to make sure the string is a valid attribute name.  The
examples below illustrate this behavior:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('-f', '--foo-bar', '--foo')
     >>> parser.add_argument('-x', '-y')
     >>> parser.parse_args('-f 1 -x 2'.split())
     Namespace(foo_bar='1', x='2')
     >>> parser.parse_args('--foo 1 -y 2'.split())
     Namespace(foo_bar='1', x='2')

‘dest’ allows a custom attribute name to be provided:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', dest='bar')
     >>> parser.parse_args('--foo XXX'.split())
     Namespace(bar='XXX')


File: python.info,  Node: deprecated,  Next: Action classes,  Prev: dest,  Up: The add_argument method

5.17.1.27 deprecated
....................

During a project’s lifetime, some arguments may need to be removed from
the command line.  Before removing them, you should inform your users
that the arguments are deprecated and will be removed.  The ‘deprecated’
keyword argument of *note add_argument(): 19e, which defaults to
‘False’, specifies if the argument is deprecated and will be removed in
the future.  For arguments, if ‘deprecated’ is ‘True’, then a warning
will be printed to *note sys.stderr: 943. when the argument is used:

     >>> import argparse
     >>> parser = argparse.ArgumentParser(prog='snake.py')
     >>> parser.add_argument('--legs', default=0, type=int, deprecated=True)
     >>> parser.parse_args([])
     Namespace(legs=0)
     >>> parser.parse_args(['--legs', '4'])
     snake.py: warning: option '--legs' is deprecated
     Namespace(legs=4)

Added in version 3.13.


File: python.info,  Node: Action classes,  Prev: deprecated,  Up: The add_argument method

5.17.1.28 Action classes
........................

‘Action’ classes implement the Action API, a callable which returns a
callable which processes arguments from the command-line.  Any object
which follows this API may be passed as the ‘action’ parameter to *note
add_argument(): 19e.

 -- Class: argparse.Action (option_strings, dest, nargs=None,
          const=None, default=None, type=None, choices=None,
          required=False, help=None, metavar=None)

     ‘Action’ objects are used by an *note ArgumentParser: 53c. to
     represent the information needed to parse a single argument from
     one or more strings from the command line.  The ‘Action’ class must
     accept the two positional arguments plus any keyword arguments
     passed to *note ArgumentParser.add_argument(): 19e. except for the
     ‘action’ itself.

     Instances of ‘Action’ (or return value of any callable to the
     ‘action’ parameter) should have attributes ‘dest’,
     ‘option_strings’, ‘default’, ‘type’, ‘required’, ‘help’, etc.
     defined.  The easiest way to ensure these attributes are defined is
     to call ‘Action.__init__()’.

      -- Method: __call__ (parser, namespace, values,
               option_string=None)

          ‘Action’ instances should be callable, so subclasses must
          override the ‘__call__()’ method, which should accept four
          parameters:

             * 'parser' - The *note ArgumentParser: 53c. object which
               contains this action.

             * 'namespace' - The *note Namespace: 305f. object that will
               be returned by *note parse_args(): 305e.  Most actions
               add an attribute to this object using *note setattr():
               2316.

             * 'values' - The associated command-line arguments, with
               any type conversions applied.  Type conversions are
               specified with the *note type: 3073. keyword argument to
               *note add_argument(): 19e.

             * 'option_string' - The option string that was used to
               invoke this action.  The ‘option_string’ argument is
               optional, and will be absent if the action is associated
               with a positional argument.

          The ‘__call__()’ method may perform arbitrary actions, but
          will typically set attributes on the ‘namespace’ based on
          ‘dest’ and ‘values’.

      -- Method: format_usage ()

          ‘Action’ subclasses can define a ‘format_usage()’ method that
          takes no argument and return a string which will be used when
          printing the usage of the program.  If such method is not
          provided, a sensible default will be used.

 -- Class: argparse.BooleanOptionalAction

     A subclass of *note Action: 1932. for handling boolean flags with
     positive and negative options.  Adding a single argument such as
     ‘--foo’ automatically creates both ‘--foo’ and ‘--no-foo’ options,
     storing ‘True’ and ‘False’ respectively:

          >>> import argparse
          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', action=argparse.BooleanOptionalAction)
          >>> parser.parse_args(['--no-foo'])
          Namespace(foo=False)

     Added in version 3.9.


File: python.info,  Node: The parse_args method,  Next: Other utilities,  Prev: The add_argument method,  Up: argparse — Parser for command-line options arguments and subcommands

5.17.1.29 The parse_args() method
.................................

 -- Method: ArgumentParser.parse_args (args=None, namespace=None)

     Convert argument strings to objects and assign them as attributes
     of the namespace.  Return the populated namespace.

     Previous calls to *note add_argument(): 19e. determine exactly what
     objects are created and how they are assigned.  See the
     documentation for ‘add_argument()’ for details.

        * *note args: 3094. - List of strings to parse.  The default is
          taken from *note sys.argv: 12ab.

        * *note namespace: 3095. - An object to take the attributes.
          The default is a new empty *note Namespace: 305f. object.

* Menu:

* Option value syntax::
* Invalid arguments::
* Arguments containing -::
* Argument abbreviations (prefix matching): Argument abbreviations prefix matching.
* Beyond sys.argv: Beyond sys argv.
* The Namespace object::


File: python.info,  Node: Option value syntax,  Next: Invalid arguments,  Up: The parse_args method

5.17.1.30 Option value syntax
.............................

The *note parse_args(): 305e. method supports several ways of specifying
the value of an option (if it takes one).  In the simplest case, the
option and its value are passed as two separate arguments:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-x')
     >>> parser.add_argument('--foo')
     >>> parser.parse_args(['-x', 'X'])
     Namespace(foo=None, x='X')
     >>> parser.parse_args(['--foo', 'FOO'])
     Namespace(foo='FOO', x=None)

For long options (options with names longer than a single character),
the option and value can also be passed as a single command-line
argument, using ‘=’ to separate them:

     >>> parser.parse_args(['--foo=FOO'])
     Namespace(foo='FOO', x=None)

For short options (options only one character long), the option and its
value can be concatenated:

     >>> parser.parse_args(['-xX'])
     Namespace(foo=None, x='X')

Several short options can be joined together, using only a single ‘-’
prefix, as long as only the last option (or none of them) requires a
value:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-x', action='store_true')
     >>> parser.add_argument('-y', action='store_true')
     >>> parser.add_argument('-z')
     >>> parser.parse_args(['-xyzZ'])
     Namespace(x=True, y=True, z='Z')


File: python.info,  Node: Invalid arguments,  Next: Arguments containing -,  Prev: Option value syntax,  Up: The parse_args method

5.17.1.31 Invalid arguments
...........................

While parsing the command line, *note parse_args(): 305e. checks for a
variety of errors, including ambiguous options, invalid types, invalid
options, wrong number of positional arguments, etc.  When it encounters
such an error, it exits and prints the error along with a usage message:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('--foo', type=int)
     >>> parser.add_argument('bar', nargs='?')

     >>> # invalid type
     >>> parser.parse_args(['--foo', 'spam'])
     usage: PROG [-h] [--foo FOO] [bar]
     PROG: error: argument --foo: invalid int value: 'spam'

     >>> # invalid option
     >>> parser.parse_args(['--bar'])
     usage: PROG [-h] [--foo FOO] [bar]
     PROG: error: no such option: --bar

     >>> # wrong number of arguments
     >>> parser.parse_args(['spam', 'badger'])
     usage: PROG [-h] [--foo FOO] [bar]
     PROG: error: extra arguments found: badger


File: python.info,  Node: Arguments containing -,  Next: Argument abbreviations prefix matching,  Prev: Invalid arguments,  Up: The parse_args method

5.17.1.32 Arguments containing ‘-’
..................................

The *note parse_args(): 305e. method attempts to give errors whenever
the user has clearly made a mistake, but some situations are inherently
ambiguous.  For example, the command-line argument ‘-1’ could either be
an attempt to specify an option or an attempt to provide a positional
argument.  The ‘parse_args()’ method is cautious here: positional
arguments may only begin with ‘-’ if they look like negative numbers and
there are no options in the parser that look like negative numbers:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-x')
     >>> parser.add_argument('foo', nargs='?')

     >>> # no negative number options, so -1 is a positional argument
     >>> parser.parse_args(['-x', '-1'])
     Namespace(foo=None, x='-1')

     >>> # no negative number options, so -1 and -5 are positional arguments
     >>> parser.parse_args(['-x', '-1', '-5'])
     Namespace(foo='-5', x='-1')

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-1', dest='one')
     >>> parser.add_argument('foo', nargs='?')

     >>> # negative number options present, so -1 is an option
     >>> parser.parse_args(['-1', 'X'])
     Namespace(foo=None, one='X')

     >>> # negative number options present, so -2 is an option
     >>> parser.parse_args(['-2'])
     usage: PROG [-h] [-1 ONE] [foo]
     PROG: error: no such option: -2

     >>> # negative number options present, so both -1s are options
     >>> parser.parse_args(['-1', '-1'])
     usage: PROG [-h] [-1 ONE] [foo]
     PROG: error: argument -1: expected one argument

If you have positional arguments that must begin with ‘-’ and don’t look
like negative numbers, you can insert the pseudo-argument ‘'--'’ which
tells *note parse_args(): 305e. that everything after that is a
positional argument:

     >>> parser.parse_args(['--', '-f'])
     Namespace(foo='-f', one=None)

See also *note the argparse howto on ambiguous arguments: 3085. for more
details.


File: python.info,  Node: Argument abbreviations prefix matching,  Next: Beyond sys argv,  Prev: Arguments containing -,  Up: The parse_args method

5.17.1.33 Argument abbreviations (prefix matching)
..................................................

The *note parse_args(): 305e. method *note by default: dee. allows long
options to be abbreviated to a prefix, if the abbreviation is
unambiguous (the prefix matches a unique option):

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-bacon')
     >>> parser.add_argument('-badger')
     >>> parser.parse_args('-bac MMM'.split())
     Namespace(bacon='MMM', badger=None)
     >>> parser.parse_args('-bad WOOD'.split())
     Namespace(bacon=None, badger='WOOD')
     >>> parser.parse_args('-ba BA'.split())
     usage: PROG [-h] [-bacon BACON] [-badger BADGER]
     PROG: error: ambiguous option: -ba could match -badger, -bacon

An error is produced for arguments that could produce more than one
options.  This feature can be disabled by setting *note allow_abbrev:
dee. to ‘False’.


File: python.info,  Node: Beyond sys argv,  Next: The Namespace object,  Prev: Argument abbreviations prefix matching,  Up: The parse_args method

5.17.1.34 Beyond ‘sys.argv’
...........................

Sometimes it may be useful to have an *note ArgumentParser: 53c. parse
arguments other than those of *note sys.argv: 12ab.  This can be
accomplished by passing a list of strings to *note parse_args(): 305e.
This is useful for testing at the interactive prompt:

     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument(
     ...     'integers', metavar='int', type=int, choices=range(10),
     ...     nargs='+', help='an integer in the range 0..9')
     >>> parser.add_argument(
     ...     '--sum', dest='accumulate', action='store_const', const=sum,
     ...     default=max, help='sum the integers (default: find the max)')
     >>> parser.parse_args(['1', '2', '3', '4'])
     Namespace(accumulate=<built-in function max>, integers=[1, 2, 3, 4])
     >>> parser.parse_args(['1', '2', '3', '4', '--sum'])
     Namespace(accumulate=<built-in function sum>, integers=[1, 2, 3, 4])


File: python.info,  Node: The Namespace object,  Prev: Beyond sys argv,  Up: The parse_args method

5.17.1.35 The Namespace object
..............................

 -- Class: argparse.Namespace

     Simple class used by default by *note parse_args(): 305e. to create
     an object holding attributes and return it.

     This class is deliberately simple, just an *note object: a9b.
     subclass with a readable string representation.  If you prefer to
     have dict-like view of the attributes, you can use the standard
     Python idiom, *note vars(): 1bd2.:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo')
          >>> args = parser.parse_args(['--foo', 'BAR'])
          >>> vars(args)
          {'foo': 'BAR'}

     It may also be useful to have an *note ArgumentParser: 53c. assign
     attributes to an already existing object, rather than a new
     ‘Namespace’ object.  This can be achieved by specifying the
     ‘namespace=’ keyword argument:

          >>> class C:
          ...     pass
          ...
          >>> c = C()
          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo')
          >>> parser.parse_args(args=['--foo', 'BAR'], namespace=c)
          >>> c.foo
          'BAR'


File: python.info,  Node: Other utilities,  Next: Exceptions<9>,  Prev: The parse_args method,  Up: argparse — Parser for command-line options arguments and subcommands

5.17.1.36 Other utilities
.........................

* Menu:

* Subcommands::
* FileType objects::
* Argument groups::
* Mutual exclusion::
* Parser defaults::
* Printing help::
* Partial parsing::
* Customizing file parsing::
* Exiting methods::
* Intermixed parsing::
* Registering custom types or actions::


File: python.info,  Node: Subcommands,  Next: FileType objects,  Up: Other utilities

5.17.1.37 Subcommands
.....................

 -- Method: ArgumentParser.add_subparsers (*[, title][, description][,
          prog][, parser_class][, action][, dest][, required][, help][,
          metavar])

     Many programs split up their functionality into a number of
     subcommands, for example, the ‘svn’ program can invoke subcommands
     like ‘svn checkout’, ‘svn update’, and ‘svn commit’.  Splitting up
     functionality this way can be a particularly good idea when a
     program performs several different functions which require
     different kinds of command-line arguments.  *note ArgumentParser:
     53c. supports the creation of such subcommands with the
     ‘add_subparsers()’ method.  The ‘add_subparsers()’ method is
     normally called with no arguments and returns a special action
     object.  This object has a single method, ‘add_parser()’, which
     takes a command name and any ‘ArgumentParser’ constructor
     arguments, and returns an ‘ArgumentParser’ object that can be
     modified as usual.

     Description of parameters:

        * 'title' - title for the sub-parser group in help output; by
          default “subcommands” if description is provided, otherwise
          uses title for positional arguments

        * 'description' - description for the sub-parser group in help
          output, by default ‘None’

        * 'prog' - usage information that will be displayed with
          subcommand help, by default the name of the program and any
          positional arguments before the subparser argument

        * 'parser_class' - class which will be used to create sub-parser
          instances, by default the class of the current parser (e.g.
          *note ArgumentParser: 53c.)

        * *note action: 307a. - the basic type of action to be taken
          when this argument is encountered at the command line

        * *note dest: 3074. - name of the attribute under which
          subcommand name will be stored; by default ‘None’ and no value
          is stored

        * *note required: 307d. - Whether or not a subcommand must be
          provided, by default ‘False’ (added in 3.7)

        * *note help: 307e. - help for sub-parser group in help output,
          by default ‘None’

        * *note metavar: 307f. - string presenting available subcommands
          in help; by default it is ‘None’ and presents subcommands in
          form {cmd1, cmd2, ..}

     Some example usage:

          >>> # create the top-level parser
          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> parser.add_argument('--foo', action='store_true', help='foo help')
          >>> subparsers = parser.add_subparsers(help='subcommand help')
          >>>
          >>> # create the parser for the "a" command
          >>> parser_a = subparsers.add_parser('a', help='a help')
          >>> parser_a.add_argument('bar', type=int, help='bar help')
          >>>
          >>> # create the parser for the "b" command
          >>> parser_b = subparsers.add_parser('b', help='b help')
          >>> parser_b.add_argument('--baz', choices=('X', 'Y', 'Z'), help='baz help')
          >>>
          >>> # parse some argument lists
          >>> parser.parse_args(['a', '12'])
          Namespace(bar=12, foo=False)
          >>> parser.parse_args(['--foo', 'b', '--baz', 'Z'])
          Namespace(baz='Z', foo=True)

     Note that the object returned by *note parse_args(): 305e. will
     only contain attributes for the main parser and the subparser that
     was selected by the command line (and not any other subparsers).
     So in the example above, when the ‘a’ command is specified, only
     the ‘foo’ and ‘bar’ attributes are present, and when the ‘b’
     command is specified, only the ‘foo’ and ‘baz’ attributes are
     present.

     Similarly, when a help message is requested from a subparser, only
     the help for that particular parser will be printed.  The help
     message will not include parent parser or sibling parser messages.
     (A help message for each subparser command, however, can be given
     by supplying the ‘help=’ argument to ‘add_parser()’ as above.)

          >>> parser.parse_args(['--help'])
          usage: PROG [-h] [--foo] {a,b} ...

          positional arguments:
            {a,b}   subcommand help
              a     a help
              b     b help

          options:
            -h, --help  show this help message and exit
            --foo   foo help

          >>> parser.parse_args(['a', '--help'])
          usage: PROG a [-h] bar

          positional arguments:
            bar     bar help

          options:
            -h, --help  show this help message and exit

          >>> parser.parse_args(['b', '--help'])
          usage: PROG b [-h] [--baz {X,Y,Z}]

          options:
            -h, --help     show this help message and exit
            --baz {X,Y,Z}  baz help

     The ‘add_subparsers()’ method also supports ‘title’ and
     ‘description’ keyword arguments.  When either is present, the
     subparser’s commands will appear in their own group in the help
     output.  For example:

          >>> parser = argparse.ArgumentParser()
          >>> subparsers = parser.add_subparsers(title='subcommands',
          ...                                    description='valid subcommands',
          ...                                    help='additional help')
          >>> subparsers.add_parser('foo')
          >>> subparsers.add_parser('bar')
          >>> parser.parse_args(['-h'])
          usage:  [-h] {foo,bar} ...

          options:
            -h, --help  show this help message and exit

          subcommands:
            valid subcommands

            {foo,bar}   additional help

     Furthermore, ‘add_parser()’ supports an additional 'aliases'
     argument, which allows multiple strings to refer to the same
     subparser.  This example, like ‘svn’, aliases ‘co’ as a shorthand
     for ‘checkout’:

          >>> parser = argparse.ArgumentParser()
          >>> subparsers = parser.add_subparsers()
          >>> checkout = subparsers.add_parser('checkout', aliases=['co'])
          >>> checkout.add_argument('foo')
          >>> parser.parse_args(['co', 'bar'])
          Namespace(foo='bar')

     ‘add_parser()’ supports also an additional 'deprecated' argument,
     which allows to deprecate the subparser.

          >>> import argparse
          >>> parser = argparse.ArgumentParser(prog='chicken.py')
          >>> subparsers = parser.add_subparsers()
          >>> run = subparsers.add_parser('run')
          >>> fly = subparsers.add_parser('fly', deprecated=True)
          >>> parser.parse_args(['fly'])
          chicken.py: warning: command 'fly' is deprecated
          Namespace()

     Added in version 3.13.

     One particularly effective way of handling subcommands is to
     combine the use of the ‘add_subparsers()’ method with calls to
     *note set_defaults(): 3076. so that each subparser knows which
     Python function it should execute.  For example:

          >>> # subcommand functions
          >>> def foo(args):
          ...     print(args.x * args.y)
          ...
          >>> def bar(args):
          ...     print('((%s))' % args.z)
          ...
          >>> # create the top-level parser
          >>> parser = argparse.ArgumentParser()
          >>> subparsers = parser.add_subparsers(required=True)
          >>>
          >>> # create the parser for the "foo" command
          >>> parser_foo = subparsers.add_parser('foo')
          >>> parser_foo.add_argument('-x', type=int, default=1)
          >>> parser_foo.add_argument('y', type=float)
          >>> parser_foo.set_defaults(func=foo)
          >>>
          >>> # create the parser for the "bar" command
          >>> parser_bar = subparsers.add_parser('bar')
          >>> parser_bar.add_argument('z')
          >>> parser_bar.set_defaults(func=bar)
          >>>
          >>> # parse the args and call whatever function was selected
          >>> args = parser.parse_args('foo 1 -x 2'.split())
          >>> args.func(args)
          2.0
          >>>
          >>> # parse the args and call whatever function was selected
          >>> args = parser.parse_args('bar XYZYX'.split())
          >>> args.func(args)
          ((XYZYX))

     This way, you can let *note parse_args(): 305e. do the job of
     calling the appropriate function after argument parsing is
     complete.  Associating functions with actions like this is
     typically the easiest way to handle the different actions for each
     of your subparsers.  However, if it is necessary to check the name
     of the subparser that was invoked, the ‘dest’ keyword argument to
     the ‘add_subparsers()’ call will work:

          >>> parser = argparse.ArgumentParser()
          >>> subparsers = parser.add_subparsers(dest='subparser_name')
          >>> subparser1 = subparsers.add_parser('1')
          >>> subparser1.add_argument('-x')
          >>> subparser2 = subparsers.add_parser('2')
          >>> subparser2.add_argument('y')
          >>> parser.parse_args(['2', 'frobble'])
          Namespace(subparser_name='2', y='frobble')

     Changed in version 3.7: New 'required' keyword-only parameter.


File: python.info,  Node: FileType objects,  Next: Argument groups,  Prev: Subcommands,  Up: Other utilities

5.17.1.38 FileType objects
..........................

 -- Class: argparse.FileType (mode='r', bufsize=-1, encoding=None,
          errors=None)

     The ‘FileType’ factory creates objects that can be passed to the
     type argument of *note ArgumentParser.add_argument(): 19e.
     Arguments that have ‘FileType’ objects as their type will open
     command-line arguments as files with the requested modes, buffer
     sizes, encodings and error handling (see the *note open(): 51f.
     function for more details):

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--raw', type=argparse.FileType('wb', 0))
          >>> parser.add_argument('out', type=argparse.FileType('w', encoding='UTF-8'))
          >>> parser.parse_args(['--raw', 'raw.dat', 'file.txt'])
          Namespace(out=<_io.TextIOWrapper name='file.txt' mode='w' encoding='UTF-8'>, raw=<_io.FileIO name='raw.dat' mode='wb'>)

     FileType objects understand the pseudo-argument ‘'-'’ and
     automatically convert this into *note sys.stdin: 540. for readable
     ‘FileType’ objects and *note sys.stdout: aec. for writable
     ‘FileType’ objects:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('infile', type=argparse.FileType('r'))
          >>> parser.parse_args(['-'])
          Namespace(infile=<_io.TextIOWrapper name='<stdin>' encoding='UTF-8'>)

     Changed in version 3.4: Added the 'encodings' and 'errors'
     parameters.


File: python.info,  Node: Argument groups,  Next: Mutual exclusion,  Prev: FileType objects,  Up: Other utilities

5.17.1.39 Argument groups
.........................

 -- Method: ArgumentParser.add_argument_group (title=None,
          description=None, *[, argument_default][, conflict_handler])

     By default, *note ArgumentParser: 53c. groups command-line
     arguments into “positional arguments” and “options” when displaying
     help messages.  When there is a better conceptual grouping of
     arguments than this default one, appropriate groups can be created
     using the ‘add_argument_group()’ method:

          >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
          >>> group = parser.add_argument_group('group')
          >>> group.add_argument('--foo', help='foo help')
          >>> group.add_argument('bar', help='bar help')
          >>> parser.print_help()
          usage: PROG [--foo FOO] bar

          group:
            bar    bar help
            --foo FOO  foo help

     The ‘add_argument_group()’ method returns an argument group object
     which has an *note add_argument(): 19e. method just like a regular
     *note ArgumentParser: 53c.  When an argument is added to the group,
     the parser treats it just like a normal argument, but displays the
     argument in a separate group for help messages.  The
     ‘add_argument_group()’ method accepts 'title' and 'description'
     arguments which can be used to customize this display:

          >>> parser = argparse.ArgumentParser(prog='PROG', add_help=False)
          >>> group1 = parser.add_argument_group('group1', 'group1 description')
          >>> group1.add_argument('foo', help='foo help')
          >>> group2 = parser.add_argument_group('group2', 'group2 description')
          >>> group2.add_argument('--bar', help='bar help')
          >>> parser.print_help()
          usage: PROG [--bar BAR] foo

          group1:
            group1 description

            foo    foo help

          group2:
            group2 description

            --bar BAR  bar help

     The optional, keyword-only parameters *note argument_default: 3069.
     and *note conflict_handler: 306a. allow for finer-grained control
     of the behavior of the argument group.  These parameters have the
     same meaning as in the *note ArgumentParser: 53c. constructor, but
     apply specifically to the argument group rather than the entire
     parser.

     Note that any arguments not in your user-defined groups will end up
     back in the usual “positional arguments” and “optional arguments”
     sections.

     Changed in version 3.11: Calling ‘add_argument_group()’ on an
     argument group is deprecated.  This feature was never supported and
     does not always work correctly.  The function exists on the API by
     accident through inheritance and will be removed in the future.


File: python.info,  Node: Mutual exclusion,  Next: Parser defaults,  Prev: Argument groups,  Up: Other utilities

5.17.1.40 Mutual exclusion
..........................

 -- Method: ArgumentParser.add_mutually_exclusive_group (required=False)

     Create a mutually exclusive group.  ‘argparse’ will make sure that
     only one of the arguments in the mutually exclusive group was
     present on the command line:

          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> group = parser.add_mutually_exclusive_group()
          >>> group.add_argument('--foo', action='store_true')
          >>> group.add_argument('--bar', action='store_false')
          >>> parser.parse_args(['--foo'])
          Namespace(bar=True, foo=True)
          >>> parser.parse_args(['--bar'])
          Namespace(bar=False, foo=False)
          >>> parser.parse_args(['--foo', '--bar'])
          usage: PROG [-h] [--foo | --bar]
          PROG: error: argument --bar: not allowed with argument --foo

     The ‘add_mutually_exclusive_group()’ method also accepts a
     'required' argument, to indicate that at least one of the mutually
     exclusive arguments is required:

          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> group = parser.add_mutually_exclusive_group(required=True)
          >>> group.add_argument('--foo', action='store_true')
          >>> group.add_argument('--bar', action='store_false')
          >>> parser.parse_args([])
          usage: PROG [-h] (--foo | --bar)
          PROG: error: one of the arguments --foo --bar is required

     Note that currently mutually exclusive argument groups do not
     support the 'title' and 'description' arguments of *note
     add_argument_group(): 30a0.  However, a mutually exclusive group
     can be added to an argument group that has a title and description.
     For example:

          >>> parser = argparse.ArgumentParser(prog='PROG')
          >>> group = parser.add_argument_group('Group title', 'Group description')
          >>> exclusive_group = group.add_mutually_exclusive_group(required=True)
          >>> exclusive_group.add_argument('--foo', help='foo help')
          >>> exclusive_group.add_argument('--bar', help='bar help')
          >>> parser.print_help()
          usage: PROG [-h] (--foo FOO | --bar BAR)

          options:
            -h, --help  show this help message and exit

          Group title:
            Group description

            --foo FOO   foo help
            --bar BAR   bar help

     Changed in version 3.11: Calling *note add_argument_group(): 30a0.
     or ‘add_mutually_exclusive_group()’ on a mutually exclusive group
     is deprecated.  These features were never supported and do not
     always work correctly.  The functions exist on the API by accident
     through inheritance and will be removed in the future.


File: python.info,  Node: Parser defaults,  Next: Printing help,  Prev: Mutual exclusion,  Up: Other utilities

5.17.1.41 Parser defaults
.........................

 -- Method: ArgumentParser.set_defaults (**kwargs)

     Most of the time, the attributes of the object returned by *note
     parse_args(): 305e. will be fully determined by inspecting the
     command-line arguments and the argument actions.  ‘set_defaults()’
     allows some additional attributes that are determined without any
     inspection of the command line to be added:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('foo', type=int)
          >>> parser.set_defaults(bar=42, baz='badger')
          >>> parser.parse_args(['736'])
          Namespace(bar=42, baz='badger', foo=736)

     Note that defaults can be set at both the parser level using
     ‘set_defaults()’ and at the argument level using *note
     add_argument(): 19e.  If both are called for the same argument, the
     last default set for an argument is used:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', default='bar')
          >>> parser.set_defaults(foo='spam')
          >>> parser.parse_args([])
          Namespace(foo='spam')

     Parser-level defaults can be particularly useful when working with
     multiple parsers.  See the *note add_subparsers(): c37. method for
     an example of this type.

 -- Method: ArgumentParser.get_default (dest)

     Get the default value for a namespace attribute, as set by either
     *note add_argument(): 19e. or by *note set_defaults(): 3076.:

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', default='badger')
          >>> parser.get_default('foo')
          'badger'


File: python.info,  Node: Printing help,  Next: Partial parsing,  Prev: Parser defaults,  Up: Other utilities

5.17.1.42 Printing help
.......................

In most typical applications, *note parse_args(): 305e. will take care
of formatting and printing any usage or error messages.  However,
several formatting methods are available:

 -- Method: ArgumentParser.print_usage (file=None)

     Print a brief description of how the *note ArgumentParser: 53c.
     should be invoked on the command line.  If 'file' is ‘None’, *note
     sys.stdout: aec. is assumed.

 -- Method: ArgumentParser.print_help (file=None)

     Print a help message, including the program usage and information
     about the arguments registered with the *note ArgumentParser: 53c.
     If 'file' is ‘None’, *note sys.stdout: aec. is assumed.

There are also variants of these methods that simply return a string
instead of printing it:

 -- Method: ArgumentParser.format_usage ()

     Return a string containing a brief description of how the *note
     ArgumentParser: 53c. should be invoked on the command line.

 -- Method: ArgumentParser.format_help ()

     Return a string containing a help message, including the program
     usage and information about the arguments registered with the *note
     ArgumentParser: 53c.


File: python.info,  Node: Partial parsing,  Next: Customizing file parsing,  Prev: Printing help,  Up: Other utilities

5.17.1.43 Partial parsing
.........................

 -- Method: ArgumentParser.parse_known_args (args=None, namespace=None)

     Sometimes a script only needs to handle a specific set of
     command-line arguments, leaving any unrecognized arguments for
     another script or program.  In these cases, the
     ‘parse_known_args()’ method can be useful.

     This method works similarly to *note parse_args(): 305e, but it
     does not raise an error for extra, unrecognized arguments.
     Instead, it parses the known arguments and returns a two item tuple
     that contains the populated namespace and the list of any
     unrecognized arguments.

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo', action='store_true')
          >>> parser.add_argument('bar')
          >>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])
          (Namespace(bar='BAR', foo=True), ['--badger', 'spam'])

     Warning: *note Prefix matching: ded. rules apply to *note
     parse_known_args(): 30aa.  The parser may consume an option even if
     it’s just a prefix of one of its known options, instead of leaving
     it in the remaining arguments list.


File: python.info,  Node: Customizing file parsing,  Next: Exiting methods,  Prev: Partial parsing,  Up: Other utilities

5.17.1.44 Customizing file parsing
..................................

 -- Method: ArgumentParser.convert_arg_line_to_args (arg_line)

     Arguments that are read from a file (see the
     'fromfile_prefix_chars' keyword argument to the *note
     ArgumentParser: 53c. constructor) are read one argument per line.
     ‘convert_arg_line_to_args()’ can be overridden for fancier reading.

     This method takes a single argument 'arg_line' which is a string
     read from the argument file.  It returns a list of arguments parsed
     from this string.  The method is called once per line read from the
     argument file, in order.

     A useful override of this method is one that treats each
     space-separated word as an argument.  The following example
     demonstrates how to do this:

          class MyArgumentParser(argparse.ArgumentParser):
              def convert_arg_line_to_args(self, arg_line):
                  return arg_line.split()


File: python.info,  Node: Exiting methods,  Next: Intermixed parsing,  Prev: Customizing file parsing,  Up: Other utilities

5.17.1.45 Exiting methods
.........................

 -- Method: ArgumentParser.exit (status=0, message=None)

     This method terminates the program, exiting with the specified
     'status' and, if given, it prints a 'message' to *note sys.stderr:
     943. before that.  The user can override this method to handle
     these steps differently:

          class ErrorCatchingArgumentParser(argparse.ArgumentParser):
              def exit(self, status=0, message=None):
                  if status:
                      raise Exception(f'Exiting because of an error: {message}')
                  exit(status)

 -- Method: ArgumentParser.error (message)

     This method prints a usage message, including the 'message', to
     *note sys.stderr: 943. and terminates the program with a status
     code of 2.


File: python.info,  Node: Intermixed parsing,  Next: Registering custom types or actions,  Prev: Exiting methods,  Up: Other utilities

5.17.1.46 Intermixed parsing
............................

 -- Method: ArgumentParser.parse_intermixed_args (args=None,
          namespace=None)

 -- Method: ArgumentParser.parse_known_intermixed_args (args=None,
          namespace=None)

     A number of Unix commands allow the user to intermix optional
     arguments with positional arguments.  The *note
     parse_intermixed_args(): b19. and ‘parse_known_intermixed_args()’
     methods support this parsing style.

     These parsers do not support all the ‘argparse’ features, and will
     raise exceptions if unsupported features are used.  In particular,
     subparsers, and mutually exclusive groups that include both
     optionals and positionals are not supported.

     The following example shows the difference between *note
     parse_known_args(): 30aa. and *note parse_intermixed_args(): b19.:
     the former returns ‘['2', '3']’ as unparsed arguments, while the
     latter collects all the positionals into ‘rest’.

          >>> parser = argparse.ArgumentParser()
          >>> parser.add_argument('--foo')
          >>> parser.add_argument('cmd')
          >>> parser.add_argument('rest', nargs='*', type=int)
          >>> parser.parse_known_args('doit 1 --foo bar 2 3'.split())
          (Namespace(cmd='doit', foo='bar', rest=[1]), ['2', '3'])
          >>> parser.parse_intermixed_args('doit 1 --foo bar 2 3'.split())
          Namespace(cmd='doit', foo='bar', rest=[1, 2, 3])

     ‘parse_known_intermixed_args()’ returns a two item tuple containing
     the populated namespace and the list of remaining argument strings.
     *note parse_intermixed_args(): b19. raises an error if there are
     any remaining unparsed argument strings.

     Added in version 3.7.


File: python.info,  Node: Registering custom types or actions,  Prev: Intermixed parsing,  Up: Other utilities

5.17.1.47 Registering custom types or actions
.............................................

 -- Method: ArgumentParser.register (registry_name, value, object)

     Sometimes it’s desirable to use a custom string in error messages
     to provide more user-friendly output.  In these cases, ‘register()’
     can be used to register custom actions or types with a parser and
     allow you to reference the type by their registered name instead of
     their callable name.

     The ‘register()’ method accepts three arguments - a
     'registry_name', specifying the internal registry where the object
     will be stored (e.g., ‘action’, ‘type’), 'value', which is the key
     under which the object will be registered, and object, the callable
     to be registered.

     The following example shows how to register a custom type with a
     parser:

          >>> import argparse
          >>> parser = argparse.ArgumentParser()
          >>> parser.register('type', 'hexadecimal integer', lambda s: int(s, 16))
          >>> parser.add_argument('--foo', type='hexadecimal integer')
          _StoreAction(option_strings=['--foo'], dest='foo', nargs=None, const=None, default=None, type='hexadecimal integer', choices=None, required=False, help=None, metavar=None, deprecated=False)
          >>> parser.parse_args(['--foo', '0xFA'])
          Namespace(foo=250)
          >>> parser.parse_args(['--foo', '1.2'])
          usage: PROG [-h] [--foo FOO]
          PROG: error: argument --foo: invalid 'hexadecimal integer' value: '1.2'


File: python.info,  Node: Exceptions<9>,  Prev: Other utilities,  Up: argparse — Parser for command-line options arguments and subcommands

5.17.1.48 Exceptions
....................

 -- Exception: argparse.ArgumentError

     An error from creating or using an argument (optional or
     positional).

     The string value of this exception is the message, augmented with
     information about the argument that caused it.

 -- Exception: argparse.ArgumentTypeError

     Raised when something goes wrong converting a command line string
     to a type.

Guides and Tutorials
....................

* Menu:

* Argparse Tutorial::
* Migrating optparse code to argparse::


File: python.info,  Node: Argparse Tutorial,  Next: Migrating optparse code to argparse,  Up: Exceptions<9>

5.17.1.49 Argparse Tutorial
...........................


author: Tshepang Mbambo

This tutorial is intended to be a gentle introduction to *note argparse:
6, the recommended command-line parsing module in the Python standard
library.

     Note: The standard library includes two other libraries directly
     related to command-line parameter processing: the lower level *note
     optparse: a0. module (which may require more code to configure for
     a given application, but also allows an application to request
     behaviors that ‘argparse’ doesn’t support), and the very low level
     *note getopt: 61. (which specifically serves as an equivalent to
     the ‘getopt()’ family of functions available to C programmers).
     While neither of those modules is covered directly in this guide,
     many of the core concepts in ‘argparse’ first originated in
     ‘optparse’, so some aspects of this tutorial will also be relevant
     to ‘optparse’ users.

* Menu:

* Concepts::
* The basics::
* Introducing Positional arguments::
* Introducing Optional arguments::
* Combining Positional and Optional arguments::
* Getting a little more advanced::
* How to translate the argparse output::
* Custom type converters::
* Conclusion::


File: python.info,  Node: Concepts,  Next: The basics,  Up: Argparse Tutorial

5.17.1.50 Concepts
..................

Let’s show the sort of functionality that we are going to explore in
this introductory tutorial by making use of the ‘ls’ command:

     $ ls
     cpython  devguide  prog.py  pypy  rm-unused-function.patch
     $ ls pypy
     ctypes_configure  demo  dotviewer  include  lib_pypy  lib-python ...
     $ ls -l
     total 20
     drwxr-xr-x 19 wena wena 4096 Feb 18 18:51 cpython
     drwxr-xr-x  4 wena wena 4096 Feb  8 12:04 devguide
     -rwxr-xr-x  1 wena wena  535 Feb 19 00:05 prog.py
     drwxr-xr-x 14 wena wena 4096 Feb  7 00:59 pypy
     -rw-r--r--  1 wena wena  741 Feb 18 01:01 rm-unused-function.patch
     $ ls --help
     Usage: ls [OPTION]... [FILE]...
     List information about the FILEs (the current directory by default).
     Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
     ...

A few concepts we can learn from the four commands:

   * The ‘ls’ command is useful when run without any options at all.  It
     defaults to displaying the contents of the current directory.

   * If we want beyond what it provides by default, we tell it a bit
     more.  In this case, we want it to display a different directory,
     ‘pypy’.  What we did is specify what is known as a positional
     argument.  It’s named so because the program should know what to do
     with the value, solely based on where it appears on the command
     line.  This concept is more relevant to a command like ‘cp’, whose
     most basic usage is ‘cp SRC DEST’.  The first position is 'what you
     want copied,' and the second position is 'where you want it copied
     to'.

   * Now, say we want to change behaviour of the program.  In our
     example, we display more info for each file instead of just showing
     the file names.  The ‘-l’ in that case is known as an optional
     argument.

   * That’s a snippet of the help text.  It’s very useful in that you
     can come across a program you have never used before, and can
     figure out how it works simply by reading its help text.


File: python.info,  Node: The basics,  Next: Introducing Positional arguments,  Prev: Concepts,  Up: Argparse Tutorial

5.17.1.51 The basics
....................

Let us start with a very simple example which does (almost) nothing:

     import argparse
     parser = argparse.ArgumentParser()
     parser.parse_args()

Following is a result of running the code:

     $ python prog.py
     $ python prog.py --help
     usage: prog.py [-h]

     options:
       -h, --help  show this help message and exit
     $ python prog.py --verbose
     usage: prog.py [-h]
     prog.py: error: unrecognized arguments: --verbose
     $ python prog.py foo
     usage: prog.py [-h]
     prog.py: error: unrecognized arguments: foo

Here is what is happening:

   * Running the script without any options results in nothing displayed
     to stdout.  Not so useful.

   * The second one starts to display the usefulness of the *note
     argparse: 6. module.  We have done almost nothing, but already we
     get a nice help message.

   * The ‘--help’ option, which can also be shortened to ‘-h’, is the
     only option we get for free (i.e.  no need to specify it).
     Specifying anything else results in an error.  But even then, we do
     get a useful usage message, also for free.


File: python.info,  Node: Introducing Positional arguments,  Next: Introducing Optional arguments,  Prev: The basics,  Up: Argparse Tutorial

5.17.1.52 Introducing Positional arguments
..........................................

An example:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("echo")
     args = parser.parse_args()
     print(args.echo)

And running the code:

     $ python prog.py
     usage: prog.py [-h] echo
     prog.py: error: the following arguments are required: echo
     $ python prog.py --help
     usage: prog.py [-h] echo

     positional arguments:
       echo

     options:
       -h, --help  show this help message and exit
     $ python prog.py foo
     foo

Here is what’s happening:

   * We’ve added the *note add_argument(): 19e. method, which is what we
     use to specify which command-line options the program is willing to
     accept.  In this case, I’ve named it ‘echo’ so that it’s in line
     with its function.

   * Calling our program now requires us to specify an option.

   * The *note parse_args(): 305e. method actually returns some data
     from the options specified, in this case, ‘echo’.

   * The variable is some form of ‘magic’ that *note argparse: 6.
     performs for free (i.e.  no need to specify which variable that
     value is stored in).  You will also notice that its name matches
     the string argument given to the method, ‘echo’.

Note however that, although the help display looks nice and all, it
currently is not as helpful as it can be.  For example we see that we
got ‘echo’ as a positional argument, but we don’t know what it does,
other than by guessing or by reading the source code.  So, let’s make it
a bit more useful:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("echo", help="echo the string you use here")
     args = parser.parse_args()
     print(args.echo)

And we get:

     $ python prog.py -h
     usage: prog.py [-h] echo

     positional arguments:
       echo        echo the string you use here

     options:
       -h, --help  show this help message and exit

Now, how about doing something even more useful:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", help="display a square of a given number")
     args = parser.parse_args()
     print(args.square**2)

Following is a result of running the code:

     $ python prog.py 4
     Traceback (most recent call last):
       File "prog.py", line 5, in <module>
         print(args.square**2)
     TypeError: unsupported operand type(s) for ** or pow(): 'str' and 'int'

That didn’t go so well.  That’s because *note argparse: 6. treats the
options we give it as strings, unless we tell it otherwise.  So, let’s
tell ‘argparse’ to treat that input as an integer:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", help="display a square of a given number",
                         type=int)
     args = parser.parse_args()
     print(args.square**2)

Following is a result of running the code:

     $ python prog.py 4
     16
     $ python prog.py four
     usage: prog.py [-h] square
     prog.py: error: argument square: invalid int value: 'four'

That went well.  The program now even helpfully quits on bad illegal
input before proceeding.


File: python.info,  Node: Introducing Optional arguments,  Next: Combining Positional and Optional arguments,  Prev: Introducing Positional arguments,  Up: Argparse Tutorial

5.17.1.53 Introducing Optional arguments
........................................

So far we have been playing with positional arguments.  Let us have a
look on how to add optional ones:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("--verbosity", help="increase output verbosity")
     args = parser.parse_args()
     if args.verbosity:
         print("verbosity turned on")

And the output:

     $ python prog.py --verbosity 1
     verbosity turned on
     $ python prog.py
     $ python prog.py --help
     usage: prog.py [-h] [--verbosity VERBOSITY]

     options:
       -h, --help            show this help message and exit
       --verbosity VERBOSITY
                             increase output verbosity
     $ python prog.py --verbosity
     usage: prog.py [-h] [--verbosity VERBOSITY]
     prog.py: error: argument --verbosity: expected one argument

Here is what is happening:

   * The program is written so as to display something when
     ‘--verbosity’ is specified and display nothing when not.

   * To show that the option is actually optional, there is no error
     when running the program without it.  Note that by default, if an
     optional argument isn’t used, the relevant variable, in this case
     ‘args.verbosity’, is given ‘None’ as a value, which is the reason
     it fails the truth test of the *note if: 2f3. statement.

   * The help message is a bit different.

   * When using the ‘--verbosity’ option, one must also specify some
     value, any value.

The above example accepts arbitrary integer values for ‘--verbosity’,
but for our simple program, only two values are actually useful, ‘True’
or ‘False’.  Let’s modify the code accordingly:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("--verbose", help="increase output verbosity",
                         action="store_true")
     args = parser.parse_args()
     if args.verbose:
         print("verbosity turned on")

And the output:

     $ python prog.py --verbose
     verbosity turned on
     $ python prog.py --verbose 1
     usage: prog.py [-h] [--verbose]
     prog.py: error: unrecognized arguments: 1
     $ python prog.py --help
     usage: prog.py [-h] [--verbose]

     options:
       -h, --help  show this help message and exit
       --verbose   increase output verbosity

Here is what is happening:

   * The option is now more of a flag than something that requires a
     value.  We even changed the name of the option to match that idea.
     Note that we now specify a new keyword, ‘action’, and give it the
     value ‘"store_true"’.  This means that, if the option is specified,
     assign the value ‘True’ to ‘args.verbose’.  Not specifying it
     implies ‘False’.

   * It complains when you specify a value, in true spirit of what flags
     actually are.

   * Notice the different help text.

* Menu:

* Short options::


File: python.info,  Node: Short options,  Up: Introducing Optional arguments

5.17.1.54 Short options
.......................

If you are familiar with command line usage, you will notice that I
haven’t yet touched on the topic of short versions of the options.  It’s
quite simple:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("-v", "--verbose", help="increase output verbosity",
                         action="store_true")
     args = parser.parse_args()
     if args.verbose:
         print("verbosity turned on")

And here goes:

     $ python prog.py -v
     verbosity turned on
     $ python prog.py --help
     usage: prog.py [-h] [-v]

     options:
       -h, --help     show this help message and exit
       -v, --verbose  increase output verbosity

Note that the new ability is also reflected in the help text.


File: python.info,  Node: Combining Positional and Optional arguments,  Next: Getting a little more advanced,  Prev: Introducing Optional arguments,  Up: Argparse Tutorial

5.17.1.55 Combining Positional and Optional arguments
.....................................................

Our program keeps growing in complexity:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display a square of a given number")
     parser.add_argument("-v", "--verbose", action="store_true",
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2
     if args.verbose:
         print(f"the square of {args.square} equals {answer}")
     else:
         print(answer)

And now the output:

     $ python prog.py
     usage: prog.py [-h] [-v] square
     prog.py: error: the following arguments are required: square
     $ python prog.py 4
     16
     $ python prog.py 4 --verbose
     the square of 4 equals 16
     $ python prog.py --verbose 4
     the square of 4 equals 16

   * We’ve brought back a positional argument, hence the complaint.

   * Note that the order does not matter.

How about we give this program of ours back the ability to have multiple
verbosity values, and actually get to use them:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display a square of a given number")
     parser.add_argument("-v", "--verbosity", type=int,
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2
     if args.verbosity == 2:
         print(f"the square of {args.square} equals {answer}")
     elif args.verbosity == 1:
         print(f"{args.square}^2 == {answer}")
     else:
         print(answer)

And the output:

     $ python prog.py 4
     16
     $ python prog.py 4 -v
     usage: prog.py [-h] [-v VERBOSITY] square
     prog.py: error: argument -v/--verbosity: expected one argument
     $ python prog.py 4 -v 1
     4^2 == 16
     $ python prog.py 4 -v 2
     the square of 4 equals 16
     $ python prog.py 4 -v 3
     16

These all look good except the last one, which exposes a bug in our
program.  Let’s fix it by restricting the values the ‘--verbosity’
option can accept:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display a square of a given number")
     parser.add_argument("-v", "--verbosity", type=int, choices=[0, 1, 2],
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2
     if args.verbosity == 2:
         print(f"the square of {args.square} equals {answer}")
     elif args.verbosity == 1:
         print(f"{args.square}^2 == {answer}")
     else:
         print(answer)

And the output:

     $ python prog.py 4 -v 3
     usage: prog.py [-h] [-v {0,1,2}] square
     prog.py: error: argument -v/--verbosity: invalid choice: 3 (choose from 0, 1, 2)
     $ python prog.py 4 -h
     usage: prog.py [-h] [-v {0,1,2}] square

     positional arguments:
       square                display a square of a given number

     options:
       -h, --help            show this help message and exit
       -v, --verbosity {0,1,2}
                             increase output verbosity

Note that the change also reflects both in the error message as well as
the help string.

Now, let’s use a different approach of playing with verbosity, which is
pretty common.  It also matches the way the CPython executable handles
its own verbosity argument (check the output of ‘python --help’):

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display the square of a given number")
     parser.add_argument("-v", "--verbosity", action="count",
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2
     if args.verbosity == 2:
         print(f"the square of {args.square} equals {answer}")
     elif args.verbosity == 1:
         print(f"{args.square}^2 == {answer}")
     else:
         print(answer)

We have introduced another action, “count”, to count the number of
occurrences of specific options.

     $ python prog.py 4
     16
     $ python prog.py 4 -v
     4^2 == 16
     $ python prog.py 4 -vv
     the square of 4 equals 16
     $ python prog.py 4 --verbosity --verbosity
     the square of 4 equals 16
     $ python prog.py 4 -v 1
     usage: prog.py [-h] [-v] square
     prog.py: error: unrecognized arguments: 1
     $ python prog.py 4 -h
     usage: prog.py [-h] [-v] square

     positional arguments:
       square           display a square of a given number

     options:
       -h, --help       show this help message and exit
       -v, --verbosity  increase output verbosity
     $ python prog.py 4 -vvv
     16

   * Yes, it’s now more of a flag (similar to ‘action="store_true"’) in
     the previous version of our script.  That should explain the
     complaint.

   * It also behaves similar to “store_true” action.

   * Now here’s a demonstration of what the “count” action gives.
     You’ve probably seen this sort of usage before.

   * And if you don’t specify the ‘-v’ flag, that flag is considered to
     have ‘None’ value.

   * As should be expected, specifying the long form of the flag, we
     should get the same output.

   * Sadly, our help output isn’t very informative on the new ability
     our script has acquired, but that can always be fixed by improving
     the documentation for our script (e.g.  via the ‘help’ keyword
     argument).

   * That last output exposes a bug in our program.

Let’s fix:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display a square of a given number")
     parser.add_argument("-v", "--verbosity", action="count",
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2

     # bugfix: replace == with >=
     if args.verbosity >= 2:
         print(f"the square of {args.square} equals {answer}")
     elif args.verbosity >= 1:
         print(f"{args.square}^2 == {answer}")
     else:
         print(answer)

And this is what it gives:

     $ python prog.py 4 -vvv
     the square of 4 equals 16
     $ python prog.py 4 -vvvv
     the square of 4 equals 16
     $ python prog.py 4
     Traceback (most recent call last):
       File "prog.py", line 11, in <module>
         if args.verbosity >= 2:
     TypeError: '>=' not supported between instances of 'NoneType' and 'int'

   * First output went well, and fixes the bug we had before.  That is,
     we want any value >= 2 to be as verbose as possible.

   * Third output not so good.

Let’s fix that bug:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("square", type=int,
                         help="display a square of a given number")
     parser.add_argument("-v", "--verbosity", action="count", default=0,
                         help="increase output verbosity")
     args = parser.parse_args()
     answer = args.square**2
     if args.verbosity >= 2:
         print(f"the square of {args.square} equals {answer}")
     elif args.verbosity >= 1:
         print(f"{args.square}^2 == {answer}")
     else:
         print(answer)

We’ve just introduced yet another keyword, ‘default’.  We’ve set it to
‘0’ in order to make it comparable to the other int values.  Remember
that by default, if an optional argument isn’t specified, it gets the
‘None’ value, and that cannot be compared to an int value (hence the
*note TypeError: 2c3. exception).

And:

     $ python prog.py 4
     16

You can go quite far just with what we’ve learned so far, and we have
only scratched the surface.  The *note argparse: 6. module is very
powerful, and we’ll explore a bit more of it before we end this
tutorial.


File: python.info,  Node: Getting a little more advanced,  Next: How to translate the argparse output,  Prev: Combining Positional and Optional arguments,  Up: Argparse Tutorial

5.17.1.56 Getting a little more advanced
........................................

What if we wanted to expand our tiny program to perform other powers,
not just squares:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("x", type=int, help="the base")
     parser.add_argument("y", type=int, help="the exponent")
     parser.add_argument("-v", "--verbosity", action="count", default=0)
     args = parser.parse_args()
     answer = args.x**args.y
     if args.verbosity >= 2:
         print(f"{args.x} to the power {args.y} equals {answer}")
     elif args.verbosity >= 1:
         print(f"{args.x}^{args.y} == {answer}")
     else:
         print(answer)

Output:

     $ python prog.py
     usage: prog.py [-h] [-v] x y
     prog.py: error: the following arguments are required: x, y
     $ python prog.py -h
     usage: prog.py [-h] [-v] x y

     positional arguments:
       x                the base
       y                the exponent

     options:
       -h, --help       show this help message and exit
       -v, --verbosity
     $ python prog.py 4 2 -v
     4^2 == 16

Notice that so far we’ve been using verbosity level to 'change' the text
that gets displayed.  The following example instead uses verbosity level
to display 'more' text instead:

     import argparse
     parser = argparse.ArgumentParser()
     parser.add_argument("x", type=int, help="the base")
     parser.add_argument("y", type=int, help="the exponent")
     parser.add_argument("-v", "--verbosity", action="count", default=0)
     args = parser.parse_args()
     answer = args.x**args.y
     if args.verbosity >= 2:
         print(f"Running '{__file__}'")
     if args.verbosity >= 1:
         print(f"{args.x}^{args.y} == ", end="")
     print(answer)

Output:

     $ python prog.py 4 2
     16
     $ python prog.py 4 2 -v
     4^2 == 16
     $ python prog.py 4 2 -vv
     Running 'prog.py'
     4^2 == 16

* Menu:

* Specifying ambiguous arguments::
* Conflicting options::


File: python.info,  Node: Specifying ambiguous arguments,  Next: Conflicting options,  Up: Getting a little more advanced

5.17.1.57 Specifying ambiguous arguments
........................................

When there is ambiguity in deciding whether an argument is positional or
for an argument, ‘--’ can be used to tell *note parse_args(): 305e. that
everything after that is a positional argument:

     >>> parser = argparse.ArgumentParser(prog='PROG')
     >>> parser.add_argument('-n', nargs='+')
     >>> parser.add_argument('args', nargs='*')

     >>> # ambiguous, so parse_args assumes it's an option
     >>> parser.parse_args(['-f'])
     usage: PROG [-h] [-n N [N ...]] [args ...]
     PROG: error: unrecognized arguments: -f

     >>> parser.parse_args(['--', '-f'])
     Namespace(args=['-f'], n=None)

     >>> # ambiguous, so the -n option greedily accepts arguments
     >>> parser.parse_args(['-n', '1', '2', '3'])
     Namespace(args=[], n=['1', '2', '3'])

     >>> parser.parse_args(['-n', '1', '--', '2', '3'])
     Namespace(args=['2', '3'], n=['1'])


File: python.info,  Node: Conflicting options,  Prev: Specifying ambiguous arguments,  Up: Getting a little more advanced

5.17.1.58 Conflicting options
.............................

So far, we have been working with two methods of an *note
argparse.ArgumentParser: 53c. instance.  Let’s introduce a third one,
*note add_mutually_exclusive_group(): 30a2.  It allows for us to specify
options that conflict with each other.  Let’s also change the rest of
the program so that the new functionality makes more sense: we’ll
introduce the ‘--quiet’ option, which will be the opposite of the
‘--verbose’ one:

     import argparse

     parser = argparse.ArgumentParser()
     group = parser.add_mutually_exclusive_group()
     group.add_argument("-v", "--verbose", action="store_true")
     group.add_argument("-q", "--quiet", action="store_true")
     parser.add_argument("x", type=int, help="the base")
     parser.add_argument("y", type=int, help="the exponent")
     args = parser.parse_args()
     answer = args.x**args.y

     if args.quiet:
         print(answer)
     elif args.verbose:
         print(f"{args.x} to the power {args.y} equals {answer}")
     else:
         print(f"{args.x}^{args.y} == {answer}")

Our program is now simpler, and we’ve lost some functionality for the
sake of demonstration.  Anyways, here’s the output:

     $ python prog.py 4 2
     4^2 == 16
     $ python prog.py 4 2 -q
     16
     $ python prog.py 4 2 -v
     4 to the power 2 equals 16
     $ python prog.py 4 2 -vq
     usage: prog.py [-h] [-v | -q] x y
     prog.py: error: argument -q/--quiet: not allowed with argument -v/--verbose
     $ python prog.py 4 2 -v --quiet
     usage: prog.py [-h] [-v | -q] x y
     prog.py: error: argument -q/--quiet: not allowed with argument -v/--verbose

That should be easy to follow.  I’ve added that last output so you can
see the sort of flexibility you get, i.e.  mixing long form options with
short form ones.

Before we conclude, you probably want to tell your users the main
purpose of your program, just in case they don’t know:

     import argparse

     parser = argparse.ArgumentParser(description="calculate X to the power of Y")
     group = parser.add_mutually_exclusive_group()
     group.add_argument("-v", "--verbose", action="store_true")
     group.add_argument("-q", "--quiet", action="store_true")
     parser.add_argument("x", type=int, help="the base")
     parser.add_argument("y", type=int, help="the exponent")
     args = parser.parse_args()
     answer = args.x**args.y

     if args.quiet:
         print(answer)
     elif args.verbose:
         print(f"{args.x} to the power {args.y} equals {answer}")
     else:
         print(f"{args.x}^{args.y} == {answer}")

Note that slight difference in the usage text.  Note the ‘[-v | -q]’,
which tells us that we can either use ‘-v’ or ‘-q’, but not both at the
same time:

     $ python prog.py --help
     usage: prog.py [-h] [-v | -q] x y

     calculate X to the power of Y

     positional arguments:
       x              the base
       y              the exponent

     options:
       -h, --help     show this help message and exit
       -v, --verbose
       -q, --quiet


File: python.info,  Node: How to translate the argparse output,  Next: Custom type converters,  Prev: Getting a little more advanced,  Up: Argparse Tutorial

5.17.1.59 How to translate the argparse output
..............................................

The output of the *note argparse: 6. module such as its help text and
error messages are all made translatable using the *note gettext: 63.
module.  This allows applications to easily localize messages produced
by ‘argparse’.  See also *note Internationalizing your programs and
modules: 30c0.

For instance, in this *note argparse: 6. output:

     $ python prog.py --help
     usage: prog.py [-h] [-v | -q] x y

     calculate X to the power of Y

     positional arguments:
       x              the base
       y              the exponent

     options:
       -h, --help     show this help message and exit
       -v, --verbose
       -q, --quiet

The strings ‘usage:’, ‘positional arguments:’, ‘options:’ and ‘show this
help message and exit’ are all translatable.

In order to translate these strings, they must first be extracted into a
‘.po’ file.  For example, using Babel(1), run this command:

     $ pybabel extract -o messages.po /usr/lib/python3.12/argparse.py

This command will extract all translatable strings from the *note
argparse: 6. module and output them into a file named ‘messages.po’.
This command assumes that your Python installation is in ‘/usr/lib’.

You can find out the location of the *note argparse: 6. module on your
system using this script:

     import argparse
     print(argparse.__file__)

Once the messages in the ‘.po’ file are translated and the translations
are installed using *note gettext: 63, *note argparse: 6. will be able
to display the translated messages.

To translate your own strings in the *note argparse: 6. output, use
*note gettext: 63.

   ---------- Footnotes ----------

   (1) https://babel.pocoo.org/


File: python.info,  Node: Custom type converters,  Next: Conclusion,  Prev: How to translate the argparse output,  Up: Argparse Tutorial

5.17.1.60 Custom type converters
................................

The *note argparse: 6. module allows you to specify custom type
converters for your command-line arguments.  This allows you to modify
user input before it’s stored in the *note argparse.Namespace: 305f.
This can be useful when you need to pre-process the input before it is
used in your program.

When using a custom type converter, you can use any callable that takes
a single string argument (the argument value) and returns the converted
value.  However, if you need to handle more complex scenarios, you can
use a custom action class with the 'action' parameter instead.

For example, let’s say you want to handle arguments with different
prefixes and process them accordingly:

     import argparse

     parser = argparse.ArgumentParser(prefix_chars='-+')

     parser.add_argument('-a', metavar='<value>', action='append',
                         type=lambda x: ('-', x))
     parser.add_argument('+a', metavar='<value>', action='append',
                         type=lambda x: ('+', x))

     args = parser.parse_args()
     print(args)

Output:

     $ python prog.py -a value1 +a value2
     Namespace(a=[('-', 'value1'), ('+', 'value2')])

In this example, we:

   * Created a parser with custom prefix characters using the
     ‘prefix_chars’ parameter.

   * Defined two arguments, ‘-a’ and ‘+a’, which used the ‘type’
     parameter to create custom type converters to store the value in a
     tuple with the prefix.

Without the custom type converters, the arguments would have treated the
‘-a’ and ‘+a’ as the same argument, which would have been undesirable.
By using custom type converters, we were able to differentiate between
the two arguments.


File: python.info,  Node: Conclusion,  Prev: Custom type converters,  Up: Argparse Tutorial

5.17.1.61 Conclusion
....................

The *note argparse: 6. module offers a lot more than shown here.  Its
docs are quite detailed and thorough, and full of examples.  Having gone
through this tutorial, you should easily digest them without feeling
overwhelmed.


File: python.info,  Node: Migrating optparse code to argparse,  Prev: Argparse Tutorial,  Up: Exceptions<9>

5.17.1.62 Migrating ‘optparse’ code to ‘argparse’
.................................................

The *note argparse: 6. module offers several higher level features not
natively provided by the *note optparse: a0. module, including:

   * Handling positional arguments.

   * Supporting subcommands.

   * Allowing alternative option prefixes like ‘+’ and ‘/’.

   * Handling zero-or-more and one-or-more style arguments.

   * Producing more informative usage messages.

   * Providing a much simpler interface for custom ‘type’ and ‘action’.

Originally, the *note argparse: 6. module attempted to maintain
compatibility with *note optparse: a0.  However, the fundamental design
differences between supporting declarative command line option
processing (while leaving positional argument processing to application
code), and supporting both named options and positional arguments in the
declarative interface mean that the API has diverged from that of
‘optparse’ over time.

As described in *note Choosing an argument parsing library: 305c,
applications that are currently using *note optparse: a0. and are happy
with the way it works can just continue to use ‘optparse’.

Application developers that are considering migrating should also review
the list of intrinsic behavioural differences described in that section
before deciding whether or not migration is desirable.

For applications that do choose to migrate from *note optparse: a0. to
*note argparse: 6, the following suggestions should be helpful:

   * Replace all *note optparse.OptionParser.add_option(): 30c7. calls
     with *note ArgumentParser.add_argument(): 19e. calls.

   * Replace ‘(options, args) = parser.parse_args()’ with ‘args =
     parser.parse_args()’ and add additional *note
     ArgumentParser.add_argument(): 19e. calls for the positional
     arguments.  Keep in mind that what was previously called ‘options’,
     now in the *note argparse: 6. context is called ‘args’.

   * Replace *note optparse.OptionParser.disable_interspersed_args():
     30c8. by using *note parse_intermixed_args(): b19. instead of *note
     parse_args(): 305e.

   * Replace callback actions and the ‘callback_*’ keyword arguments
     with ‘type’ or ‘action’ arguments.

   * Replace string names for ‘type’ keyword arguments with the
     corresponding type objects (e.g.  int, float, complex, etc).

   * Replace *note optparse.Values: 30c9. with *note Namespace: 305f.
     and *note optparse.OptionError: 30ca. and *note
     optparse.OptionValueError: 30cb. with *note ArgumentError: 30b3.

   * Replace strings with implicit arguments such as ‘%default’ or
     ‘%prog’ with the standard Python syntax to use dictionaries to
     format strings, that is, ‘%(default)s’ and ‘%(prog)s’.

   * Replace the OptionParser constructor ‘version’ argument with a call
     to ‘parser.add_argument('--version', action='version',
     version='<the version>')’.


File: python.info,  Node: optparse — Parser for command line options,  Next: getpass — Portable password input,  Prev: argparse — Parser for command-line options arguments and subcommands,  Up: Command-line interface libraries

5.17.2 ‘optparse’ — Parser for command line options
---------------------------------------------------

'Source code:' Lib/optparse.py(1)

__________________________________________________________________

* Menu:

* Choosing an argument parsing library::
* Introduction: Introduction<7>.
* Background::
* Tutorial: Tutorial<2>.
* Reference Guide::
* Option Callbacks::
* Extending optparse::
* Exceptions: Exceptions<10>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/optparse.py


File: python.info,  Node: Choosing an argument parsing library,  Next: Introduction<7>,  Up: optparse — Parser for command line options

5.17.2.1 Choosing an argument parsing library
.............................................

The standard library includes three argument parsing libraries:

   * *note getopt: 61.: a module that closely mirrors the procedural C
     ‘getopt’ API. Included in the standard library since before the
     initial Python 1.0 release.

   * ‘optparse’: a declarative replacement for ‘getopt’ that provides
     equivalent functionality without requiring each application to
     implement its own procedural option parsing logic.  Included in the
     standard library since the Python 2.3 release.

   * *note argparse: 6.: a more opinionated alternative to ‘optparse’
     that provides more functionality by default, at the expense of
     reduced application flexibility in controlling exactly how
     arguments are processed.  Included in the standard library since
     the Python 2.7 and Python 3.2 releases.

In the absence of more specific argument parsing design constraints,
*note argparse: 6. is the recommended choice for implementing command
line applications, as it offers the highest level of baseline
functionality with the least application level code.

*note getopt: 61. is retained almost entirely for backwards
compatibility reasons.  However, it also serves a niche use case as a
tool for prototyping and testing command line argument handling in
‘getopt’-based C applications.

‘optparse’ should be considered as an alternative to *note argparse: 6.
in the following cases:

   * an application is already using ‘optparse’ and doesn’t want to risk
     the subtle behavioural changes that may arise when migrating to
     *note argparse: 6.

   * the application requires additional control over the way options
     and positional parameters are interleaved on the command line
     (including the ability to disable the interleaving feature
     completely)

   * the application requires additional control over the incremental
     parsing of command line elements (while ‘argparse’ does support
     this, the exact way it works in practice is undesirable for some
     use cases)

   * the application requires additional control over the handling of
     options which accept parameter values that may start with ‘-’ (such
     as delegated options to be passed to invoked subprocesses)

   * the application requires some other command line parameter
     processing behavior which ‘argparse’ does not support, but which
     can be implemented in terms of the lower level interface offered by
     ‘optparse’

These considerations also mean that ‘optparse’ is likely to provide a
better foundation for library authors writing third party command line
argument processing libraries.

As a concrete example, consider the following two command line argument
parsing configurations, the first using ‘optparse’, and the second using
‘argparse’:

     import optparse

     if __name__ == '__main__':
         parser = optparse.OptionParser()
         parser.add_option('-o', '--output')
         parser.add_option('-v', dest='verbose', action='store_true')
         opts, args = parser.parse_args()
         process(args, output=opts.output, verbose=opts.verbose)

     import argparse

     if __name__ == '__main__':
         parser = argparse.ArgumentParser()
         parser.add_argument('-o', '--output')
         parser.add_argument('-v', dest='verbose', action='store_true')
         parser.add_argument('rest', nargs='*')
         args = parser.parse_args()
         process(args.rest, output=args.output, verbose=args.verbose)

The most obvious difference is that in the ‘optparse’ version, the
non-option arguments are processed separately by the application after
the option processing is complete.  In the ‘argparse’ version,
positional arguments are declared and processed in the same way as the
named options.

However, the ‘argparse’ version will also handle some parameter
combination differently from the way the ‘optparse’ version would handle
them.  For example (amongst other differences):

   * supplying ‘-o -v’ gives ‘output="-v"’ and ‘verbose=False’ when
     using ‘optparse’, but a usage error with ‘argparse’ (complaining
     that no value has been supplied for ‘-o/--output’, since ‘-v’ is
     interpreted as meaning the verbosity flag)

   * similarly, supplying ‘-o --’ gives ‘output="--"’ and ‘args=()’ when
     using ‘optparse’, but a usage error with ‘argparse’ (also
     complaining that no value has been supplied for ‘-o/--output’,
     since ‘--’ is interpreted as terminating the option processing and
     treating all remaining values as positional arguments)

   * supplying ‘-o=foo’ gives ‘output="=foo"’ when using ‘optparse’, but
     gives ‘output="foo"’ with ‘argparse’ (since ‘=’ is special cased as
     an alternative separator for option parameter values)

Whether these differing behaviors in the ‘argparse’ version are
considered desirable or a problem will depend on the specific command
line application use case.

See also
........

click(1) is a third party argument processing library (originally based
on ‘optparse’), which allows command line applications to be developed
as a set of decorated command implementation functions.

Other third party libraries, such as typer(2) or msgspec-click(3), allow
command line interfaces to be specified in ways that more effectively
integrate with static checking of Python type annotations.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/click/

   (2) https://pypi.org/project/typer/

   (3) https://pypi.org/project/msgspec-click/


File: python.info,  Node: Introduction<7>,  Next: Background,  Prev: Choosing an argument parsing library,  Up: optparse — Parser for command line options

5.17.2.2 Introduction
.....................

‘optparse’ is a more convenient, flexible, and powerful library for
parsing command-line options than the minimalist *note getopt: 61.
module.  ‘optparse’ uses a more declarative style of command-line
parsing: you create an instance of *note OptionParser: 151c, populate it
with options, and parse the command line.  ‘optparse’ allows users to
specify options in the conventional GNU/POSIX syntax, and additionally
generates usage and help messages for you.

Here’s an example of using ‘optparse’ in a simple script:

     from optparse import OptionParser
     ...
     parser = OptionParser()
     parser.add_option("-f", "--file", dest="filename",
                       help="write report to FILE", metavar="FILE")
     parser.add_option("-q", "--quiet",
                       action="store_false", dest="verbose", default=True,
                       help="don't print status messages to stdout")

     (options, args) = parser.parse_args()

With these few lines of code, users of your script can now do the “usual
thing” on the command-line, for example:

     <yourscript> --file=outfile -q

As it parses the command line, ‘optparse’ sets attributes of the
‘options’ object returned by *note parse_args(): 151d. based on
user-supplied command-line values.  When ‘parse_args()’ returns from
parsing this command line, ‘options.filename’ will be ‘"outfile"’ and
‘options.verbose’ will be ‘False’.  ‘optparse’ supports both long and
short options, allows short options to be merged together, and allows
options to be associated with their arguments in a variety of ways.
Thus, the following command lines are all equivalent to the above
example:

     <yourscript> -f outfile --quiet
     <yourscript> --quiet --file outfile
     <yourscript> -q -foutfile
     <yourscript> -qfoutfile

Additionally, users can run one of the following

     <yourscript> -h
     <yourscript> --help

and ‘optparse’ will print out a brief summary of your script’s options:

     Usage: <yourscript> [options]

     Options:
       -h, --help            show this help message and exit
       -f FILE, --file=FILE  write report to FILE
       -q, --quiet           don't print status messages to stdout

where the value of 'yourscript' is determined at runtime (normally from
‘sys.argv[0]’).


File: python.info,  Node: Background,  Next: Tutorial<2>,  Prev: Introduction<7>,  Up: optparse — Parser for command line options

5.17.2.3 Background
...................

‘optparse’ was explicitly designed to encourage the creation of programs
with straightforward command-line interfaces that follow the conventions
established by the ‘getopt()’ family of functions available to C
developers.  To that end, it supports only the most common command-line
syntax and semantics conventionally used under Unix.  If you are
unfamiliar with these conventions, reading this section will allow you
to acquaint yourself with them.

* Menu:

* Terminology::
* What are options for?::
* What are positional arguments for?::


File: python.info,  Node: Terminology,  Next: What are options for?,  Up: Background

5.17.2.4 Terminology
....................

argument

     a string entered on the command-line, and passed by the shell to
     ‘execl()’ or ‘execv()’.  In Python, arguments are elements of
     ‘sys.argv[1:]’ (‘sys.argv[0]’ is the name of the program being
     executed).  Unix shells also use the term “word”.

     It is occasionally desirable to substitute an argument list other
     than ‘sys.argv[1:]’, so you should read “argument” as “an element
     of ‘sys.argv[1:]’, or of some other list provided as a substitute
     for ‘sys.argv[1:]’”.

option

     an argument used to supply extra information to guide or customize
     the execution of a program.  There are many different syntaxes for
     options; the traditional Unix syntax is a hyphen (“-”) followed by
     a single letter, e.g.  ‘-x’ or ‘-F’.  Also, traditional Unix syntax
     allows multiple options to be merged into a single argument, e.g.
     ‘-x -F’ is equivalent to ‘-xF’.  The GNU project introduced ‘--’
     followed by a series of hyphen-separated words, e.g.  ‘--file’ or
     ‘--dry-run’.  These are the only two option syntaxes provided by
     ‘optparse’.

     Some other option syntaxes that the world has seen include:

        * a hyphen followed by a few letters, e.g.  ‘-pf’ (this is 'not'
          the same as multiple options merged into a single argument)

        * a hyphen followed by a whole word, e.g.  ‘-file’ (this is
          technically equivalent to the previous syntax, but they aren’t
          usually seen in the same program)

        * a plus sign followed by a single letter, or a few letters, or
          a word, e.g.  ‘+f’, ‘+rgb’

        * a slash followed by a letter, or a few letters, or a word,
          e.g.  ‘/f’, ‘/file’

     These option syntaxes are not supported by ‘optparse’, and they
     never will be.  This is deliberate: the first three are
     non-standard on any environment, and the last only makes sense if
     you’re exclusively targeting Windows or certain legacy platforms
     (e.g.  VMS, MS-DOS).

option argument

     an argument that follows an option, is closely associated with that
     option, and is consumed from the argument list when that option is.
     With ‘optparse’, option arguments may either be in a separate
     argument from their option:

          -f foo
          --file foo

     or included in the same argument:

          -ffoo
          --file=foo

     Typically, a given option either takes an argument or it doesn’t.
     Lots of people want an “optional option arguments” feature, meaning
     that some options will take an argument if they see it, and won’t
     if they don’t.  This is somewhat controversial, because it makes
     parsing ambiguous: if ‘-a’ takes an optional argument and ‘-b’ is
     another option entirely, how do we interpret ‘-ab’?  Because of
     this ambiguity, ‘optparse’ does not support this feature.

positional argument

     something leftover in the argument list after options have been
     parsed, i.e.  after options and their arguments have been parsed
     and removed from the argument list.

required option

     an option that must be supplied on the command-line; note that the
     phrase “required option” is self-contradictory in English.
     ‘optparse’ doesn’t prevent you from implementing required options,
     but doesn’t give you much help at it either.

For example, consider this hypothetical command-line:

     prog -v --report report.txt foo bar

‘-v’ and ‘--report’ are both options.  Assuming that ‘--report’ takes
one argument, ‘report.txt’ is an option argument.  ‘foo’ and ‘bar’ are
positional arguments.


File: python.info,  Node: What are options for?,  Next: What are positional arguments for?,  Prev: Terminology,  Up: Background

5.17.2.5 What are options for?
..............................

Options are used to provide extra information to tune or customize the
execution of a program.  In case it wasn’t clear, options are usually
'optional'.  A program should be able to run just fine with no options
whatsoever.  (Pick a random program from the Unix or GNU toolsets.  Can
it run without any options at all and still make sense?  The main
exceptions are ‘find’, ‘tar’, and ‘dd’—all of which are mutant oddballs
that have been rightly criticized for their non-standard syntax and
confusing interfaces.)

Lots of people want their programs to have “required options”.  Think
about it.  If it’s required, then it’s 'not optional'!  If there is a
piece of information that your program absolutely requires in order to
run successfully, that’s what positional arguments are for.

As an example of good command-line interface design, consider the humble
‘cp’ utility, for copying files.  It doesn’t make much sense to try to
copy files without supplying a destination and at least one source.
Hence, ‘cp’ fails if you run it with no arguments.  However, it has a
flexible, useful syntax that does not require any options at all:

     cp SOURCE DEST
     cp SOURCE ... DEST-DIR

You can get pretty far with just that.  Most ‘cp’ implementations
provide a bunch of options to tweak exactly how the files are copied:
you can preserve mode and modification time, avoid following symlinks,
ask before clobbering existing files, etc.  But none of this distracts
from the core mission of ‘cp’, which is to copy either one file to
another, or several files to another directory.


File: python.info,  Node: What are positional arguments for?,  Prev: What are options for?,  Up: Background

5.17.2.6 What are positional arguments for?
...........................................

Positional arguments are for those pieces of information that your
program absolutely, positively requires to run.

A good user interface should have as few absolute requirements as
possible.  If your program requires 17 distinct pieces of information in
order to run successfully, it doesn’t much matter 'how' you get that
information from the user—most people will give up and walk away before
they successfully run the program.  This applies whether the user
interface is a command-line, a configuration file, or a GUI: if you make
that many demands on your users, most of them will simply give up.

In short, try to minimize the amount of information that users are
absolutely required to supply—use sensible defaults whenever possible.
Of course, you also want to make your programs reasonably flexible.
That’s what options are for.  Again, it doesn’t matter if they are
entries in a config file, widgets in the “Preferences” dialog of a GUI,
or command-line options—the more options you implement, the more
flexible your program is, and the more complicated its implementation
becomes.  Too much flexibility has drawbacks as well, of course; too
many options can overwhelm users and make your code much harder to
maintain.


File: python.info,  Node: Tutorial<2>,  Next: Reference Guide,  Prev: Background,  Up: optparse — Parser for command line options

5.17.2.7 Tutorial
.................

While ‘optparse’ is quite flexible and powerful, it’s also
straightforward to use in most cases.  This section covers the code
patterns that are common to any ‘optparse’-based program.

First, you need to import the OptionParser class; then, early in the
main program, create an OptionParser instance:

     from optparse import OptionParser
     ...
     parser = OptionParser()

Then you can start defining options.  The basic syntax is:

     parser.add_option(opt_str, ...,
                       attr=value, ...)

Each option has one or more option strings, such as ‘-f’ or ‘--file’,
and several option attributes that tell ‘optparse’ what to expect and
what to do when it encounters that option on the command line.

Typically, each option will have one short option string and one long
option string, e.g.:

     parser.add_option("-f", "--file", ...)

You’re free to define as many short option strings and as many long
option strings as you like (including zero), as long as there is at
least one option string overall.

The option strings passed to *note OptionParser.add_option(): 30c7. are
effectively labels for the option defined by that call.  For brevity, we
will frequently refer to 'encountering an option' on the command line;
in reality, ‘optparse’ encounters 'option strings' and looks up options
from them.

Once all of your options are defined, instruct ‘optparse’ to parse your
program’s command line:

     (options, args) = parser.parse_args()

(If you like, you can pass a custom argument list to *note parse_args():
151d, but that’s rarely necessary: by default it uses ‘sys.argv[1:]’.)

*note parse_args(): 151d. returns two values:

   * ‘options’, an object containing values for all of your options—e.g.
     if ‘--file’ takes a single string argument, then ‘options.file’
     will be the filename supplied by the user, or ‘None’ if the user
     did not supply that option

   * ‘args’, the list of positional arguments leftover after parsing
     options

This tutorial section only covers the four most important option
attributes: *note action: 30db, *note type: 30dc, *note dest: 30dd.
(destination), and *note help: 30de.  Of these, ‘action’ is the most
fundamental.

* Menu:

* Understanding option actions::
* The store action::
* Handling boolean (flag) options: Handling boolean flag options.
* Other actions::
* Default values::
* Generating help::
* Printing a version string::
* How optparse handles errors::
* Putting it all together::


File: python.info,  Node: Understanding option actions,  Next: The store action,  Up: Tutorial<2>

5.17.2.8 Understanding option actions
.....................................

Actions tell ‘optparse’ what to do when it encounters an option on the
command line.  There is a fixed set of actions hard-coded into
‘optparse’; adding new actions is an advanced topic covered in section
*note Extending optparse: 30e1.  Most actions tell ‘optparse’ to store a
value in some variable—for example, take a string from the command line
and store it in an attribute of ‘options’.

If you don’t specify an option action, ‘optparse’ defaults to ‘store’.


File: python.info,  Node: The store action,  Next: Handling boolean flag options,  Prev: Understanding option actions,  Up: Tutorial<2>

5.17.2.9 The store action
.........................

The most common option action is ‘store’, which tells ‘optparse’ to take
the next argument (or the remainder of the current argument), ensure
that it is of the correct type, and store it to your chosen destination.

For example:

     parser.add_option("-f", "--file",
                       action="store", type="string", dest="filename")

Now let’s make up a fake command line and ask ‘optparse’ to parse it:

     args = ["-f", "foo.txt"]
     (options, args) = parser.parse_args(args)

When ‘optparse’ sees the option string ‘-f’, it consumes the next
argument, ‘foo.txt’, and stores it in ‘options.filename’.  So, after
this call to *note parse_args(): 151d, ‘options.filename’ is
‘"foo.txt"’.

Some other option types supported by ‘optparse’ are ‘int’ and ‘float’.
Here’s an option that expects an integer argument:

     parser.add_option("-n", type="int", dest="num")

Note that this option has no long option string, which is perfectly
acceptable.  Also, there’s no explicit action, since the default is
‘store’.

Let’s parse another fake command-line.  This time, we’ll jam the option
argument right up against the option: since ‘-n42’ (one argument) is
equivalent to ‘-n 42’ (two arguments), the code

     (options, args) = parser.parse_args(["-n42"])
     print(options.num)

will print ‘42’.

If you don’t specify a type, ‘optparse’ assumes ‘string’.  Combined with
the fact that the default action is ‘store’, that means our first
example can be a lot shorter:

     parser.add_option("-f", "--file", dest="filename")

If you don’t supply a destination, ‘optparse’ figures out a sensible
default from the option strings: if the first long option string is
‘--foo-bar’, then the default destination is ‘foo_bar’.  If there are no
long option strings, ‘optparse’ looks at the first short option string:
the default destination for ‘-f’ is ‘f’.

‘optparse’ also includes the built-in ‘complex’ type.  Adding types is
covered in section *note Extending optparse: 30e1.


File: python.info,  Node: Handling boolean flag options,  Next: Other actions,  Prev: The store action,  Up: Tutorial<2>

5.17.2.10 Handling boolean (flag) options
.........................................

Flag options—set a variable to true or false when a particular option is
seen—are quite common.  ‘optparse’ supports them with two separate
actions, ‘store_true’ and ‘store_false’.  For example, you might have a
‘verbose’ flag that is turned on with ‘-v’ and off with ‘-q’:

     parser.add_option("-v", action="store_true", dest="verbose")
     parser.add_option("-q", action="store_false", dest="verbose")

Here we have two different options with the same destination, which is
perfectly OK. (It just means you have to be a bit careful when setting
default values—see below.)

When ‘optparse’ encounters ‘-v’ on the command line, it sets
‘options.verbose’ to ‘True’; when it encounters ‘-q’, ‘options.verbose’
is set to ‘False’.


File: python.info,  Node: Other actions,  Next: Default values,  Prev: Handling boolean flag options,  Up: Tutorial<2>

5.17.2.11 Other actions
.......................

Some other actions supported by ‘optparse’ are:

‘"store_const"’

     store a constant value, pre-set via *note Option.const: 30e8.

‘"append"’

     append this option’s argument to a list

‘"count"’

     increment a counter by one

‘"callback"’

     call a specified function

These are covered in section *note Reference Guide: 30e9, and section
*note Option Callbacks: 30ea.


File: python.info,  Node: Default values,  Next: Generating help,  Prev: Other actions,  Up: Tutorial<2>

5.17.2.12 Default values
........................

All of the above examples involve setting some variable (the
“destination”) when certain command-line options are seen.  What happens
if those options are never seen?  Since we didn’t supply any defaults,
they are all set to ‘None’.  This is usually fine, but sometimes you
want more control.  ‘optparse’ lets you supply a default value for each
destination, which is assigned before the command line is parsed.

First, consider the verbose/quiet example.  If we want ‘optparse’ to set
‘verbose’ to ‘True’ unless ‘-q’ is seen, then we can do this:

     parser.add_option("-v", action="store_true", dest="verbose", default=True)
     parser.add_option("-q", action="store_false", dest="verbose")

Since default values apply to the 'destination' rather than to any
particular option, and these two options happen to have the same
destination, this is exactly equivalent:

     parser.add_option("-v", action="store_true", dest="verbose")
     parser.add_option("-q", action="store_false", dest="verbose", default=True)

Consider this:

     parser.add_option("-v", action="store_true", dest="verbose", default=False)
     parser.add_option("-q", action="store_false", dest="verbose", default=True)

Again, the default value for ‘verbose’ will be ‘True’: the last default
value supplied for any particular destination is the one that counts.

A clearer way to specify default values is the ‘set_defaults()’ method
of OptionParser, which you can call at any time before calling *note
parse_args(): 151d.:

     parser.set_defaults(verbose=True)
     parser.add_option(...)
     (options, args) = parser.parse_args()

As before, the last value specified for a given option destination is
the one that counts.  For clarity, try to use one method or the other of
setting default values, not both.


File: python.info,  Node: Generating help,  Next: Printing a version string,  Prev: Default values,  Up: Tutorial<2>

5.17.2.13 Generating help
.........................

‘optparse’’s ability to generate help and usage text automatically is
useful for creating user-friendly command-line interfaces.  All you have
to do is supply a *note help: 30de. value for each option, and
optionally a short usage message for your whole program.  Here’s an
OptionParser populated with user-friendly (documented) options:

     usage = "usage: %prog [options] arg1 arg2"
     parser = OptionParser(usage=usage)
     parser.add_option("-v", "--verbose",
                       action="store_true", dest="verbose", default=True,
                       help="make lots of noise [default]")
     parser.add_option("-q", "--quiet",
                       action="store_false", dest="verbose",
                       help="be vewwy quiet (I'm hunting wabbits)")
     parser.add_option("-f", "--filename",
                       metavar="FILE", help="write output to FILE")
     parser.add_option("-m", "--mode",
                       default="intermediate",
                       help="interaction mode: novice, intermediate, "
                            "or expert [default: %default]")

If ‘optparse’ encounters either ‘-h’ or ‘--help’ on the command-line, or
if you just call ‘parser.print_help()’, it prints the following to
standard output:

     Usage: <yourscript> [options] arg1 arg2

     Options:
       -h, --help            show this help message and exit
       -v, --verbose         make lots of noise [default]
       -q, --quiet           be vewwy quiet (I'm hunting wabbits)
       -f FILE, --filename=FILE
                             write output to FILE
       -m MODE, --mode=MODE  interaction mode: novice, intermediate, or
                             expert [default: intermediate]

(If the help output is triggered by a help option, ‘optparse’ exits
after printing the help text.)

There’s a lot going on here to help ‘optparse’ generate the best
possible help message:

   * the script defines its own usage message:

          usage = "usage: %prog [options] arg1 arg2"

     ‘optparse’ expands ‘%prog’ in the usage string to the name of the
     current program, i.e.  ‘os.path.basename(sys.argv[0])’.  The
     expanded string is then printed before the detailed option help.

     If you don’t supply a usage string, ‘optparse’ uses a bland but
     sensible default: ‘"Usage: %prog [options]"’, which is fine if your
     script doesn’t take any positional arguments.

   * every option defines a help string, and doesn’t worry about
     line-wrapping—‘optparse’ takes care of wrapping lines and making
     the help output look good.

   * options that take a value indicate this fact in their automatically
     generated help message, e.g.  for the “mode” option:

          -m MODE, --mode=MODE

     Here, “MODE” is called the meta-variable: it stands for the
     argument that the user is expected to supply to ‘-m’/‘--mode’.  By
     default, ‘optparse’ converts the destination variable name to
     uppercase and uses that for the meta-variable.  Sometimes, that’s
     not what you want—for example, the ‘--filename’ option explicitly
     sets ‘metavar="FILE"’, resulting in this automatically generated
     option description:

          -f FILE, --filename=FILE

     This is important for more than just saving space, though: the
     manually written help text uses the meta-variable ‘FILE’ to clue
     the user in that there’s a connection between the semi-formal
     syntax ‘-f FILE’ and the informal semantic description “write
     output to FILE”.  This is a simple but effective way to make your
     help text a lot clearer and more useful for end users.

   * options that have a default value can include ‘%default’ in the
     help string—‘optparse’ will replace it with *note str(): 44f. of
     the option’s default value.  If an option has no default value (or
     the default value is ‘None’), ‘%default’ expands to ‘none’.

* Menu:

* Grouping Options::


File: python.info,  Node: Grouping Options,  Up: Generating help

5.17.2.14 Grouping Options
..........................

When dealing with many options, it is convenient to group these options
for better help output.  An *note OptionParser: 151c. can contain
several option groups, each of which can contain several options.

An option group is obtained using the class *note OptionGroup: 30f0.:

 -- Class: optparse.OptionGroup (parser, title, description=None)

     where

        * parser is the *note OptionParser: 151c. instance the group
          will be inserted in to

        * title is the group title

        * description, optional, is a long description of the group

*note OptionGroup: 30f0. inherits from ‘OptionContainer’ (like *note
OptionParser: 151c.) and so the ‘add_option()’ method can be used to add
an option to the group.

Once all the options are declared, using the *note OptionParser: 151c.
method ‘add_option_group()’ the group is added to the previously defined
parser.

Continuing with the parser defined in the previous section, adding an
*note OptionGroup: 30f0. to a parser is easy:

     group = OptionGroup(parser, "Dangerous Options",
                         "Caution: use these options at your own risk.  "
                         "It is believed that some of them bite.")
     group.add_option("-g", action="store_true", help="Group option.")
     parser.add_option_group(group)

This would result in the following help output:

     Usage: <yourscript> [options] arg1 arg2

     Options:
       -h, --help            show this help message and exit
       -v, --verbose         make lots of noise [default]
       -q, --quiet           be vewwy quiet (I'm hunting wabbits)
       -f FILE, --filename=FILE
                             write output to FILE
       -m MODE, --mode=MODE  interaction mode: novice, intermediate, or
                             expert [default: intermediate]

       Dangerous Options:
         Caution: use these options at your own risk.  It is believed that some
         of them bite.

         -g                  Group option.

A bit more complete example might involve using more than one group:
still extending the previous example:

     group = OptionGroup(parser, "Dangerous Options",
                         "Caution: use these options at your own risk.  "
                         "It is believed that some of them bite.")
     group.add_option("-g", action="store_true", help="Group option.")
     parser.add_option_group(group)

     group = OptionGroup(parser, "Debug Options")
     group.add_option("-d", "--debug", action="store_true",
                      help="Print debug information")
     group.add_option("-s", "--sql", action="store_true",
                      help="Print all SQL statements executed")
     group.add_option("-e", action="store_true", help="Print every action done")
     parser.add_option_group(group)

that results in the following output:

     Usage: <yourscript> [options] arg1 arg2

     Options:
       -h, --help            show this help message and exit
       -v, --verbose         make lots of noise [default]
       -q, --quiet           be vewwy quiet (I'm hunting wabbits)
       -f FILE, --filename=FILE
                             write output to FILE
       -m MODE, --mode=MODE  interaction mode: novice, intermediate, or expert
                             [default: intermediate]

       Dangerous Options:
         Caution: use these options at your own risk.  It is believed that some
         of them bite.

         -g                  Group option.

       Debug Options:
         -d, --debug         Print debug information
         -s, --sql           Print all SQL statements executed
         -e                  Print every action done

Another interesting method, in particular when working programmatically
with option groups is:

 -- Method: OptionParser.get_option_group (opt_str)

     Return the *note OptionGroup: 30f0. to which the short or long
     option string 'opt_str' (e.g.  ‘'-o'’ or ‘'--option'’) belongs.  If
     there’s no such ‘OptionGroup’, return ‘None’.


File: python.info,  Node: Printing a version string,  Next: How optparse handles errors,  Prev: Generating help,  Up: Tutorial<2>

5.17.2.15 Printing a version string
...................................

Similar to the brief usage string, ‘optparse’ can also print a version
string for your program.  You have to supply the string as the ‘version’
argument to OptionParser:

     parser = OptionParser(usage="%prog [-f] [-q]", version="%prog 1.0")

‘%prog’ is expanded just like it is in ‘usage’.  Apart from that,
‘version’ can contain anything you like.  When you supply it, ‘optparse’
automatically adds a ‘--version’ option to your parser.  If it
encounters this option on the command line, it expands your ‘version’
string (by replacing ‘%prog’), prints it to stdout, and exits.

For example, if your script is called ‘/usr/bin/foo’:

     $ /usr/bin/foo --version
     foo 1.0

The following two methods can be used to print and get the ‘version’
string:

 -- Method: OptionParser.print_version (file=None)

     Print the version message for the current program (‘self.version’)
     to 'file' (default stdout).  As with *note print_usage(): 30f5, any
     occurrence of ‘%prog’ in ‘self.version’ is replaced with the name
     of the current program.  Does nothing if ‘self.version’ is empty or
     undefined.

 -- Method: OptionParser.get_version ()

     Same as *note print_version(): 30f4. but returns the version string
     instead of printing it.


File: python.info,  Node: How optparse handles errors,  Next: Putting it all together,  Prev: Printing a version string,  Up: Tutorial<2>

5.17.2.16 How ‘optparse’ handles errors
.......................................

There are two broad classes of errors that ‘optparse’ has to worry
about: programmer errors and user errors.  Programmer errors are usually
erroneous calls to *note OptionParser.add_option(): 30c7, e.g.  invalid
option strings, unknown option attributes, missing option attributes,
etc.  These are dealt with in the usual way: raise an exception (either
*note optparse.OptionError: 30ca. or *note TypeError: 2c3.) and let the
program crash.

Handling user errors is much more important, since they are guaranteed
to happen no matter how stable your code is.  ‘optparse’ can
automatically detect some user errors, such as bad option arguments
(passing ‘-n 4x’ where ‘-n’ takes an integer argument), missing
arguments (‘-n’ at the end of the command line, where ‘-n’ takes an
argument of any type).  Also, you can call ‘OptionParser.error()’ to
signal an application-defined error condition:

     (options, args) = parser.parse_args()
     ...
     if options.a and options.b:
         parser.error("options -a and -b are mutually exclusive")

In either case, ‘optparse’ handles the error the same way: it prints the
program’s usage message and an error message to standard error and exits
with error status 2.

Consider the first example above, where the user passes ‘4x’ to an
option that takes an integer:

     $ /usr/bin/foo -n 4x
     Usage: foo [options]

     foo: error: option -n: invalid integer value: '4x'

Or, where the user fails to pass a value at all:

     $ /usr/bin/foo -n
     Usage: foo [options]

     foo: error: -n option requires an argument

‘optparse’-generated error messages take care always to mention the
option involved in the error; be sure to do the same when calling
‘OptionParser.error()’ from your application code.

If ‘optparse’’s default error-handling behaviour does not suit your
needs, you’ll need to subclass OptionParser and override its ‘exit()’
and/or ‘error()’ methods.


File: python.info,  Node: Putting it all together,  Prev: How optparse handles errors,  Up: Tutorial<2>

5.17.2.17 Putting it all together
.................................

Here’s what ‘optparse’-based scripts usually look like:

     from optparse import OptionParser
     ...
     def main():
         usage = "usage: %prog [options] arg"
         parser = OptionParser(usage)
         parser.add_option("-f", "--file", dest="filename",
                           help="read data from FILENAME")
         parser.add_option("-v", "--verbose",
                           action="store_true", dest="verbose")
         parser.add_option("-q", "--quiet",
                           action="store_false", dest="verbose")
         ...
         (options, args) = parser.parse_args()
         if len(args) != 1:
             parser.error("incorrect number of arguments")
         if options.verbose:
             print("reading %s..." % options.filename)
         ...

     if __name__ == "__main__":
         main()


File: python.info,  Node: Reference Guide,  Next: Option Callbacks,  Prev: Tutorial<2>,  Up: optparse — Parser for command line options

5.17.2.18 Reference Guide
.........................

* Menu:

* Creating the parser::
* Populating the parser::
* Defining options::
* Option attributes::
* Standard option actions::
* Standard option types::
* Parsing arguments::
* Querying and manipulating your option parser::
* Conflicts between options::
* Cleanup::
* Other methods::


File: python.info,  Node: Creating the parser,  Next: Populating the parser,  Up: Reference Guide

5.17.2.19 Creating the parser
.............................

The first step in using ‘optparse’ is to create an OptionParser
instance.

 -- Class: optparse.OptionParser (...)

     The OptionParser constructor has no required arguments, but a
     number of optional keyword arguments.  You should always pass them
     as keyword arguments, i.e.  do not rely on the order in which the
     arguments are declared.

     ‘usage’ (default: ‘"%prog [options]"’)

          The usage summary to print when your program is run
          incorrectly or with a help option.  When ‘optparse’ prints the
          usage string, it expands ‘%prog’ to
          ‘os.path.basename(sys.argv[0])’ (or to ‘prog’ if you passed
          that keyword argument).  To suppress a usage message, pass the
          special value ‘optparse.SUPPRESS_USAGE’.

     ‘option_list’ (default: ‘[]’)

          A list of Option objects to populate the parser with.  The
          options in ‘option_list’ are added after any options in
          ‘standard_option_list’ (a class attribute that may be set by
          OptionParser subclasses), but before any version or help
          options.  Deprecated; use *note add_option(): 30c7. after
          creating the parser instead.

     ‘option_class’ (default: optparse.Option)

          Class to use when adding options to the parser in *note
          add_option(): 30c7.

     ‘version’ (default: ‘None’)

          A version string to print when the user supplies a version
          option.  If you supply a true value for ‘version’, ‘optparse’
          automatically adds a version option with the single option
          string ‘--version’.  The substring ‘%prog’ is expanded the
          same as for ‘usage’.

     ‘conflict_handler’ (default: ‘"error"’)

          Specifies what to do when options with conflicting option
          strings are added to the parser; see section *note Conflicts
          between options: 30fe.

     ‘description’ (default: ‘None’)

          A paragraph of text giving a brief overview of your program.
          ‘optparse’ reformats this paragraph to fit the current
          terminal width and prints it when the user requests help
          (after ‘usage’, but before the list of options).

     ‘formatter’ (default: a new ‘IndentedHelpFormatter’)

          An instance of optparse.HelpFormatter that will be used for
          printing help text.  ‘optparse’ provides two concrete classes
          for this purpose: IndentedHelpFormatter and
          TitledHelpFormatter.

     ‘add_help_option’ (default: ‘True’)

          If true, ‘optparse’ will add a help option (with option
          strings ‘-h’ and ‘--help’) to the parser.

     ‘prog’

          The string to use when expanding ‘%prog’ in ‘usage’ and
          ‘version’ instead of ‘os.path.basename(sys.argv[0])’.

     ‘epilog’ (default: ‘None’)

          A paragraph of help text to print after the option help.


File: python.info,  Node: Populating the parser,  Next: Defining options,  Prev: Creating the parser,  Up: Reference Guide

5.17.2.20 Populating the parser
...............................

There are several ways to populate the parser with options.  The
preferred way is by using *note OptionParser.add_option(): 30c7, as
shown in section *note Tutorial: 30d9.  ‘add_option()’ can be called in
one of two ways:

   * pass it an Option instance (as returned by ‘make_option()’)

   * pass it any combination of positional and keyword arguments that
     are acceptable to ‘make_option()’ (i.e., to the Option
     constructor), and it will create the Option instance for you

The other alternative is to pass a list of pre-constructed Option
instances to the OptionParser constructor, as in:

     option_list = [
         make_option("-f", "--filename",
                     action="store", type="string", dest="filename"),
         make_option("-q", "--quiet",
                     action="store_false", dest="verbose"),
         ]
     parser = OptionParser(option_list=option_list)

(‘make_option()’ is a factory function for creating Option instances;
currently it is an alias for the Option constructor.  A future version
of ‘optparse’ may split Option into several classes, and ‘make_option()’
will pick the right class to instantiate.  Do not instantiate Option
directly.)


File: python.info,  Node: Defining options,  Next: Option attributes,  Prev: Populating the parser,  Up: Reference Guide

5.17.2.21 Defining options
..........................

Each Option instance represents a set of synonymous command-line option
strings, e.g.  ‘-f’ and ‘--file’.  You can specify any number of short
or long option strings, but you must specify at least one overall option
string.

The canonical way to create an *note Option: 3103. instance is with the
‘add_option()’ method of *note OptionParser: 151c.

 -- Method: OptionParser.add_option (option)

 -- Method: OptionParser.add_option (*opt_str, attr=value, ...)

     To define an option with only a short option string:

          parser.add_option("-f", attr=value, ...)

     And to define an option with only a long option string:

          parser.add_option("--foo", attr=value, ...)

     The keyword arguments define attributes of the new Option object.
     The most important option attribute is *note action: 30db, and it
     largely determines which other attributes are relevant or required.
     If you pass irrelevant option attributes, or fail to pass required
     ones, ‘optparse’ raises an *note OptionError: 30ca. exception
     explaining your mistake.

     An option’s 'action' determines what ‘optparse’ does when it
     encounters this option on the command-line.  The standard option
     actions hard-coded into ‘optparse’ are:

     ‘"store"’

          store this option’s argument (default)

     ‘"store_const"’

          store a constant value, pre-set via *note Option.const: 30e8.

     ‘"store_true"’

          store ‘True’

     ‘"store_false"’

          store ‘False’

     ‘"append"’

          append this option’s argument to a list

     ‘"append_const"’

          append a constant value to a list, pre-set via *note
          Option.const: 30e8.

     ‘"count"’

          increment a counter by one

     ‘"callback"’

          call a specified function

     ‘"help"’

          print a usage message including all options and the
          documentation for them

     (If you don’t supply an action, the default is ‘"store"’.  For this
     action, you may also supply *note type: 30dc. and *note dest: 30dd.
     option attributes; see *note Standard option actions: 3104.)

As you can see, most actions involve storing or updating a value
somewhere.  ‘optparse’ always creates a special object for this,
conventionally called ‘options’, which is an instance of *note
optparse.Values: 30c9.

 -- Class: optparse.Values

     An object holding parsed argument names and values as attributes.
     Normally created by calling when calling *note
     OptionParser.parse_args(): 151d, and can be overridden by a custom
     subclass passed to the 'values' argument of
     ‘OptionParser.parse_args()’ (as described in *note Parsing
     arguments: 3105.).

Option arguments (and various other values) are stored as attributes of
this object, according to the *note dest: 30dd. (destination) option
attribute.

For example, when you call

     parser.parse_args()

one of the first things ‘optparse’ does is create the ‘options’ object:

     options = Values()

If one of the options in this parser is defined with

     parser.add_option("-f", "--file", action="store", type="string", dest="filename")

and the command-line being parsed includes any of the following:

     -ffoo
     -f foo
     --file=foo
     --file foo

then ‘optparse’, on seeing this option, will do the equivalent of

     options.filename = "foo"

The *note type: 30dc. and *note dest: 30dd. option attributes are almost
as important as *note action: 30db, but ‘action’ is the only one that
makes sense for 'all' options.


File: python.info,  Node: Option attributes,  Next: Standard option actions,  Prev: Defining options,  Up: Reference Guide

5.17.2.22 Option attributes
...........................

 -- Class: optparse.Option

     A single command line argument, with various attributes passed by
     keyword to the constructor.  Normally created with *note
     OptionParser.add_option(): 30c7. rather than directly, and can be
     overridden by a custom class via the 'option_class' argument to
     *note OptionParser: 151c.

The following option attributes may be passed as keyword arguments to
*note OptionParser.add_option(): 30c7.  If you pass an option attribute
that is not relevant to a particular option, or fail to pass a required
option attribute, ‘optparse’ raises *note OptionError: 30ca.

 -- Attribute: Option.action

     (default: ‘"store"’)

     Determines ‘optparse’’s behaviour when this option is seen on the
     command line; the available options are documented *note here:
     3104.

 -- Attribute: Option.type

     (default: ‘"string"’)

     The argument type expected by this option (e.g., ‘"string"’ or
     ‘"int"’); the available option types are documented *note here:
     3108.

 -- Attribute: Option.dest

     (default: derived from option strings)

     If the option’s action implies writing or modifying a value
     somewhere, this tells ‘optparse’ where to write it: ‘dest’ names an
     attribute of the ‘options’ object that ‘optparse’ builds as it
     parses the command line.

 -- Attribute: Option.default

     The value to use for this option’s destination if the option is not
     seen on the command line.  See also *note
     OptionParser.set_defaults(): 310a.

 -- Attribute: Option.nargs

     (default: 1)

     How many arguments of type *note type: 30dc. should be consumed
     when this option is seen.  If > 1, ‘optparse’ will store a tuple of
     values to *note dest: 30dd.

 -- Attribute: Option.const

     For actions that store a constant value, the constant value to
     store.

 -- Attribute: Option.choices

     For options of type ‘"choice"’, the list of strings the user may
     choose from.

 -- Attribute: Option.callback

     For options with action ‘"callback"’, the callable to call when
     this option is seen.  See section *note Option Callbacks: 30ea. for
     detail on the arguments passed to the callable.

 -- Attribute: Option.callback_args
 -- Attribute: Option.callback_kwargs

     Additional positional and keyword arguments to pass to ‘callback’
     after the four standard callback arguments.

 -- Attribute: Option.help

     Help text to print for this option when listing all available
     options after the user supplies a ‘help’ option (such as ‘--help’).
     If no help text is supplied, the option will be listed without help
     text.  To hide this option, use the special value
     ‘optparse.SUPPRESS_HELP’.

 -- Attribute: Option.metavar

     (default: derived from option strings)

     Stand-in for the option argument(s) to use when printing help text.
     See section *note Tutorial: 30d9. for an example.


File: python.info,  Node: Standard option actions,  Next: Standard option types,  Prev: Option attributes,  Up: Reference Guide

5.17.2.23 Standard option actions
.................................

The various option actions all have slightly different requirements and
effects.  Most actions have several relevant option attributes which you
may specify to guide ‘optparse’’s behaviour; a few have required
attributes, which you must specify for any option using that action.

   * ‘"store"’ [relevant: *note type: 30dc, *note dest: 30dd, *note
     nargs: 310b, *note choices: 310c.]

     The option must be followed by an argument, which is converted to a
     value according to *note type: 30dc. and stored in *note dest:
     30dd.  If *note nargs: 310b. > 1, multiple arguments will be
     consumed from the command line; all will be converted according to
     ‘type’ and stored to ‘dest’ as a tuple.  See the *note Standard
     option types: 3108. section.

     If *note choices: 310c. is supplied (a list or tuple of strings),
     the type defaults to ‘"choice"’.

     If *note type: 30dc. is not supplied, it defaults to ‘"string"’.

     If *note dest: 30dd. is not supplied, ‘optparse’ derives a
     destination from the first long option string (e.g., ‘--foo-bar’
     implies ‘foo_bar’).  If there are no long option strings,
     ‘optparse’ derives a destination from the first short option string
     (e.g., ‘-f’ implies ‘f’).

     Example:

          parser.add_option("-f")
          parser.add_option("-p", type="float", nargs=3, dest="point")

     As it parses the command line

          -f foo.txt -p 1 -3.5 4 -fbar.txt

     ‘optparse’ will set

          options.f = "foo.txt"
          options.point = (1.0, -3.5, 4.0)
          options.f = "bar.txt"

   * ‘"store_const"’ [required: *note const: 30e8.; relevant: *note
     dest: 30dd.]

     The value *note const: 30e8. is stored in *note dest: 30dd.

     Example:

          parser.add_option("-q", "--quiet",
                            action="store_const", const=0, dest="verbose")
          parser.add_option("-v", "--verbose",
                            action="store_const", const=1, dest="verbose")
          parser.add_option("--noisy",
                            action="store_const", const=2, dest="verbose")

     If ‘--noisy’ is seen, ‘optparse’ will set

          options.verbose = 2

   * ‘"store_true"’ [relevant: *note dest: 30dd.]

     A special case of ‘"store_const"’ that stores ‘True’ to *note dest:
     30dd.

   * ‘"store_false"’ [relevant: *note dest: 30dd.]

     Like ‘"store_true"’, but stores ‘False’.

     Example:

          parser.add_option("--clobber", action="store_true", dest="clobber")
          parser.add_option("--no-clobber", action="store_false", dest="clobber")

   * ‘"append"’ [relevant: *note type: 30dc, *note dest: 30dd, *note
     nargs: 310b, *note choices: 310c.]

     The option must be followed by an argument, which is appended to
     the list in *note dest: 30dd.  If no default value for ‘dest’ is
     supplied, an empty list is automatically created when ‘optparse’
     first encounters this option on the command-line.  If *note nargs:
     310b. > 1, multiple arguments are consumed, and a tuple of length
     ‘nargs’ is appended to ‘dest’.

     The defaults for *note type: 30dc. and *note dest: 30dd. are the
     same as for the ‘"store"’ action.

     Example:

          parser.add_option("-t", "--tracks", action="append", type="int")

     If ‘-t3’ is seen on the command-line, ‘optparse’ does the
     equivalent of:

          options.tracks = []
          options.tracks.append(int("3"))

     If, a little later on, ‘--tracks=4’ is seen, it does:

          options.tracks.append(int("4"))

     The ‘append’ action calls the ‘append’ method on the current value
     of the option.  This means that any default value specified must
     have an ‘append’ method.  It also means that if the default value
     is non-empty, the default elements will be present in the parsed
     value for the option, with any values from the command line
     appended after those default values:

          >>> parser.add_option("--files", action="append", default=['~/.mypkg/defaults'])
          >>> opts, args = parser.parse_args(['--files', 'overrides.mypkg'])
          >>> opts.files
          ['~/.mypkg/defaults', 'overrides.mypkg']

   * ‘"append_const"’ [required: *note const: 30e8.; relevant: *note
     dest: 30dd.]

     Like ‘"store_const"’, but the value *note const: 30e8. is appended
     to *note dest: 30dd.; as with ‘"append"’, ‘dest’ defaults to
     ‘None’, and an empty list is automatically created the first time
     the option is encountered.

   * ‘"count"’ [relevant: *note dest: 30dd.]

     Increment the integer stored at *note dest: 30dd.  If no default
     value is supplied, ‘dest’ is set to zero before being incremented
     the first time.

     Example:

          parser.add_option("-v", action="count", dest="verbosity")

     The first time ‘-v’ is seen on the command line, ‘optparse’ does
     the equivalent of:

          options.verbosity = 0
          options.verbosity += 1

     Every subsequent occurrence of ‘-v’ results in

          options.verbosity += 1

   * ‘"callback"’ [required: *note callback: 310d.; relevant: *note
     type: 30dc, *note nargs: 310b, *note callback_args: 310e, *note
     callback_kwargs: 310f.]

     Call the function specified by *note callback: 310d, which is
     called as

          func(option, opt_str, value, parser, *args, **kwargs)

     See section *note Option Callbacks: 30ea. for more detail.

   * ‘"help"’

     Prints a complete help message for all the options in the current
     option parser.  The help message is constructed from the ‘usage’
     string passed to OptionParser’s constructor and the *note help:
     30de. string passed to every option.

     If no *note help: 30de. string is supplied for an option, it will
     still be listed in the help message.  To omit an option entirely,
     use the special value ‘optparse.SUPPRESS_HELP’.

     ‘optparse’ automatically adds a *note help: 30de. option to all
     OptionParsers, so you do not normally need to create one.

     Example:

          from optparse import OptionParser, SUPPRESS_HELP

          # usually, a help option is added automatically, but that can
          # be suppressed using the add_help_option argument
          parser = OptionParser(add_help_option=False)

          parser.add_option("-h", "--help", action="help")
          parser.add_option("-v", action="store_true", dest="verbose",
                            help="Be moderately verbose")
          parser.add_option("--file", dest="filename",
                            help="Input file to read data from")
          parser.add_option("--secret", help=SUPPRESS_HELP)

     If ‘optparse’ sees either ‘-h’ or ‘--help’ on the command line, it
     will print something like the following help message to stdout
     (assuming ‘sys.argv[0]’ is ‘"foo.py"’):

          Usage: foo.py [options]

          Options:
            -h, --help        Show this help message and exit
            -v                Be moderately verbose
            --file=FILENAME   Input file to read data from

     After printing the help message, ‘optparse’ terminates your process
     with ‘sys.exit(0)’.

   * ‘"version"’

     Prints the version number supplied to the OptionParser to stdout
     and exits.  The version number is actually formatted and printed by
     the ‘print_version()’ method of OptionParser.  Generally only
     relevant if the ‘version’ argument is supplied to the OptionParser
     constructor.  As with *note help: 30de. options, you will rarely
     create ‘version’ options, since ‘optparse’ automatically adds them
     when needed.


File: python.info,  Node: Standard option types,  Next: Parsing arguments,  Prev: Standard option actions,  Up: Reference Guide

5.17.2.24 Standard option types
...............................

‘optparse’ has five built-in option types: ‘"string"’, ‘"int"’,
‘"choice"’, ‘"float"’ and ‘"complex"’.  If you need to add new option
types, see section *note Extending optparse: 30e1.

Arguments to string options are not checked or converted in any way: the
text on the command line is stored in the destination (or passed to the
callback) as-is.

Integer arguments (type ‘"int"’) are parsed as follows:

   * if the number starts with ‘0x’, it is parsed as a hexadecimal
     number

   * if the number starts with ‘0’, it is parsed as an octal number

   * if the number starts with ‘0b’, it is parsed as a binary number

   * otherwise, the number is parsed as a decimal number

The conversion is done by calling *note int(): 257. with the appropriate
base (2, 8, 10, or 16).  If this fails, so will ‘optparse’, although
with a more useful error message.

‘"float"’ and ‘"complex"’ option arguments are converted directly with
*note float(): 2f7. and *note complex(): 2f8, with similar
error-handling.

‘"choice"’ options are a subtype of ‘"string"’ options.  The *note
choices: 310c. option attribute (a sequence of strings) defines the set
of allowed option arguments.  ‘optparse.check_choice()’ compares
user-supplied option arguments against this master list and raises *note
OptionValueError: 30cb. if an invalid string is given.


File: python.info,  Node: Parsing arguments,  Next: Querying and manipulating your option parser,  Prev: Standard option types,  Up: Reference Guide

5.17.2.25 Parsing arguments
...........................

The whole point of creating and populating an OptionParser is to call
its *note parse_args(): 151d. method.

 -- Method: OptionParser.parse_args (args=None, values=None)

     Parse the command-line options found in 'args'.

     The input parameters are

     ‘args’

          the list of arguments to process (default: ‘sys.argv[1:]’)

     ‘values’

          a *note Values: 30c9. object to store option arguments in
          (default: a new instance of ‘Values’) – if you give an
          existing object, the option defaults will not be initialized
          on it

     and the return value is a pair ‘(options, args)’ where

     ‘options’

          the same object that was passed in as 'values', or the
          ‘optparse.Values’ instance created by ‘optparse’

     ‘args’

          the leftover positional arguments after all options have been
          processed

The most common usage is to supply neither keyword argument.  If you
supply ‘values’, it will be modified with repeated *note setattr():
2316. calls (roughly one for every option argument stored to an option
destination) and returned by *note parse_args(): 151d.

If *note parse_args(): 151d. encounters any errors in the argument list,
it calls the OptionParser’s ‘error()’ method with an appropriate
end-user error message.  This ultimately terminates your process with an
exit status of 2 (the traditional Unix exit status for command-line
errors).


File: python.info,  Node: Querying and manipulating your option parser,  Next: Conflicts between options,  Prev: Parsing arguments,  Up: Reference Guide

5.17.2.26 Querying and manipulating your option parser
......................................................

The default behavior of the option parser can be customized slightly,
and you can also poke around your option parser and see what’s there.
OptionParser provides several methods to help you out:

 -- Method: OptionParser.disable_interspersed_args ()

     Set parsing to stop on the first non-option.  For example, if ‘-a’
     and ‘-b’ are both simple options that take no arguments, ‘optparse’
     normally accepts this syntax:

          prog -a arg1 -b arg2

     and treats it as equivalent to

          prog -a -b arg1 arg2

     To disable this feature, call ‘disable_interspersed_args()’.  This
     restores traditional Unix syntax, where option parsing stops with
     the first non-option argument.

     Use this if you have a command processor which runs another command
     which has options of its own and you want to make sure these
     options don’t get confused.  For example, each command might have a
     different set of options.

 -- Method: OptionParser.enable_interspersed_args ()

     Set parsing to not stop on the first non-option, allowing
     interspersing switches with command arguments.  This is the default
     behavior.

 -- Method: OptionParser.get_option (opt_str)

     Returns the Option instance with the option string 'opt_str', or
     ‘None’ if no options have that option string.

 -- Method: OptionParser.has_option (opt_str)

     Return ‘True’ if the OptionParser has an option with option string
     'opt_str' (e.g., ‘-q’ or ‘--verbose’).

 -- Method: OptionParser.remove_option (opt_str)

     If the *note OptionParser: 151c. has an option corresponding to
     'opt_str', that option is removed.  If that option provided any
     other option strings, all of those option strings become invalid.
     If 'opt_str' does not occur in any option belonging to this
     ‘OptionParser’, raises *note ValueError: 202.


File: python.info,  Node: Conflicts between options,  Next: Cleanup,  Prev: Querying and manipulating your option parser,  Up: Reference Guide

5.17.2.27 Conflicts between options
...................................

If you’re not careful, it’s easy to define options with conflicting
option strings:

     parser.add_option("-n", "--dry-run", ...)
     ...
     parser.add_option("-n", "--noisy", ...)

(This is particularly true if you’ve defined your own OptionParser
subclass with some standard options.)

Every time you add an option, ‘optparse’ checks for conflicts with
existing options.  If it finds any, it invokes the current
conflict-handling mechanism.  You can set the conflict-handling
mechanism either in the constructor:

     parser = OptionParser(..., conflict_handler=handler)

or with a separate call:

     parser.set_conflict_handler(handler)

The available conflict handlers are:

     ‘"error"’ (default)

          assume option conflicts are a programming error and raise
          *note OptionConflictError: 311b.

     ‘"resolve"’

          resolve option conflicts intelligently (see below)

As an example, let’s define an *note OptionParser: 151c. that resolves
conflicts intelligently and add conflicting options to it:

     parser = OptionParser(conflict_handler="resolve")
     parser.add_option("-n", "--dry-run", ..., help="do no harm")
     parser.add_option("-n", "--noisy", ..., help="be noisy")

At this point, ‘optparse’ detects that a previously added option is
already using the ‘-n’ option string.  Since ‘conflict_handler’ is
‘"resolve"’, it resolves the situation by removing ‘-n’ from the earlier
option’s list of option strings.  Now ‘--dry-run’ is the only way for
the user to activate that option.  If the user asks for help, the help
message will reflect that:

     Options:
       --dry-run     do no harm
       ...
       -n, --noisy   be noisy

It’s possible to whittle away the option strings for a previously added
option until there are none left, and the user has no way of invoking
that option from the command-line.  In that case, ‘optparse’ removes
that option completely, so it doesn’t show up in help text or anywhere
else.  Carrying on with our existing OptionParser:

     parser.add_option("--dry-run", ..., help="new dry-run option")

At this point, the original ‘-n’/‘--dry-run’ option is no longer
accessible, so ‘optparse’ removes it, leaving this help text:

     Options:
       ...
       -n, --noisy   be noisy
       --dry-run     new dry-run option


File: python.info,  Node: Cleanup,  Next: Other methods,  Prev: Conflicts between options,  Up: Reference Guide

5.17.2.28 Cleanup
.................

OptionParser instances have several cyclic references.  This should not
be a problem for Python’s garbage collector, but you may wish to break
the cyclic references explicitly by calling ‘destroy()’ on your
OptionParser once you are done with it.  This is particularly useful in
long-running applications where large object graphs are reachable from
your OptionParser.


File: python.info,  Node: Other methods,  Prev: Cleanup,  Up: Reference Guide

5.17.2.29 Other methods
.......................

OptionParser supports several other public methods:

 -- Method: OptionParser.set_usage (usage)

     Set the usage string according to the rules described above for the
     ‘usage’ constructor keyword argument.  Passing ‘None’ sets the
     default usage string; use ‘optparse.SUPPRESS_USAGE’ to suppress a
     usage message.

 -- Method: OptionParser.print_usage (file=None)

     Print the usage message for the current program (‘self.usage’) to
     'file' (default stdout).  Any occurrence of the string ‘%prog’ in
     ‘self.usage’ is replaced with the name of the current program.
     Does nothing if ‘self.usage’ is empty or not defined.

 -- Method: OptionParser.get_usage ()

     Same as *note print_usage(): 30f5. but returns the usage string
     instead of printing it.

 -- Method: OptionParser.set_defaults (dest=value, ...)

     Set default values for several option destinations at once.  Using
     ‘set_defaults()’ is the preferred way to set default values for
     options, since multiple options can share the same destination.
     For example, if several “mode” options all set the same
     destination, any one of them can set the default, and the last one
     wins:

          parser.add_option("--advanced", action="store_const",
                            dest="mode", const="advanced",
                            default="novice")    # overridden below
          parser.add_option("--novice", action="store_const",
                            dest="mode", const="novice",
                            default="advanced")  # overrides above setting

     To avoid this confusion, use ‘set_defaults()’:

          parser.set_defaults(mode="advanced")
          parser.add_option("--advanced", action="store_const",
                            dest="mode", const="advanced")
          parser.add_option("--novice", action="store_const",
                            dest="mode", const="novice")


File: python.info,  Node: Option Callbacks,  Next: Extending optparse,  Prev: Reference Guide,  Up: optparse — Parser for command line options

5.17.2.30 Option Callbacks
..........................

When ‘optparse’’s built-in actions and types aren’t quite enough for
your needs, you have two choices: extend ‘optparse’ or define a callback
option.  Extending ‘optparse’ is more general, but overkill for a lot of
simple cases.  Quite often a simple callback is all you need.

There are two steps to defining a callback option:

   * define the option itself using the ‘"callback"’ action

   * write the callback; this is a function (or method) that takes at
     least four arguments, as described below

* Menu:

* Defining a callback option::
* How callbacks are called::
* Raising errors in a callback::
* Callback example 1; trivial callback: Callback example 1 trivial callback.
* Callback example 2; check option order: Callback example 2 check option order.
* Callback example 3; check option order (generalized): Callback example 3 check option order generalized.
* Callback example 4; check arbitrary condition: Callback example 4 check arbitrary condition.
* Callback example 5; fixed arguments: Callback example 5 fixed arguments.
* Callback example 6; variable arguments: Callback example 6 variable arguments.


File: python.info,  Node: Defining a callback option,  Next: How callbacks are called,  Up: Option Callbacks

5.17.2.31 Defining a callback option
....................................

As always, the easiest way to define a callback option is by using the
*note OptionParser.add_option(): 30c7. method.  Apart from *note action:
30db, the only option attribute you must specify is ‘callback’, the
function to call:

     parser.add_option("-c", action="callback", callback=my_callback)

‘callback’ is a function (or other callable object), so you must have
already defined ‘my_callback()’ when you create this callback option.
In this simple case, ‘optparse’ doesn’t even know if ‘-c’ takes any
arguments, which usually means that the option takes no arguments—the
mere presence of ‘-c’ on the command-line is all it needs to know.  In
some circumstances, though, you might want your callback to consume an
arbitrary number of command-line arguments.  This is where writing
callbacks gets tricky; it’s covered later in this section.

‘optparse’ always passes four particular arguments to your callback, and
it will only pass additional arguments if you specify them via *note
callback_args: 310e. and *note callback_kwargs: 310f.  Thus, the minimal
callback function signature is:

     def my_callback(option, opt, value, parser):

The four arguments to a callback are described below.

There are several other option attributes that you can supply when you
define a callback option:

*note type: 30dc.

     has its usual meaning: as with the ‘"store"’ or ‘"append"’ actions,
     it instructs ‘optparse’ to consume one argument and convert it to
     *note type: 30dc.  Rather than storing the converted value(s)
     anywhere, though, ‘optparse’ passes it to your callback function.

*note nargs: 310b.

     also has its usual meaning: if it is supplied and > 1, ‘optparse’
     will consume *note nargs: 310b. arguments, each of which must be
     convertible to *note type: 30dc.  It then passes a tuple of
     converted values to your callback.

*note callback_args: 310e.

     a tuple of extra positional arguments to pass to the callback

*note callback_kwargs: 310f.

     a dictionary of extra keyword arguments to pass to the callback


File: python.info,  Node: How callbacks are called,  Next: Raising errors in a callback,  Prev: Defining a callback option,  Up: Option Callbacks

5.17.2.32 How callbacks are called
..................................

All callbacks are called as follows:

     func(option, opt_str, value, parser, *args, **kwargs)

where

‘option’

     is the Option instance that’s calling the callback

‘opt_str’

     is the option string seen on the command-line that’s triggering the
     callback.  (If an abbreviated long option was used, ‘opt_str’ will
     be the full, canonical option string—e.g.  if the user puts ‘--foo’
     on the command-line as an abbreviation for ‘--foobar’, then
     ‘opt_str’ will be ‘"--foobar"’.)

‘value’

     is the argument to this option seen on the command-line.
     ‘optparse’ will only expect an argument if *note type: 30dc. is
     set; the type of ‘value’ will be the type implied by the option’s
     type.  If ‘type’ for this option is ‘None’ (no argument expected),
     then ‘value’ will be ‘None’.  If *note nargs: 310b. > 1, ‘value’
     will be a tuple of values of the appropriate type.

‘parser’

     is the OptionParser instance driving the whole thing, mainly useful
     because you can access some other interesting data through its
     instance attributes:

     ‘parser.largs’

          the current list of leftover arguments, ie.  arguments that
          have been consumed but are neither options nor option
          arguments.  Feel free to modify ‘parser.largs’, e.g.  by
          adding more arguments to it.  (This list will become ‘args’,
          the second return value of *note parse_args(): 151d.)

     ‘parser.rargs’

          the current list of remaining arguments, ie.  with ‘opt_str’
          and ‘value’ (if applicable) removed, and only the arguments
          following them still there.  Feel free to modify
          ‘parser.rargs’, e.g.  by consuming more arguments.

     ‘parser.values’

          the object where option values are by default stored (an
          instance of optparse.OptionValues).  This lets callbacks use
          the same mechanism as the rest of ‘optparse’ for storing
          option values; you don’t need to mess around with globals or
          closures.  You can also access or modify the value(s) of any
          options already encountered on the command-line.

‘args’

     is a tuple of arbitrary positional arguments supplied via the *note
     callback_args: 310e. option attribute.

‘kwargs’

     is a dictionary of arbitrary keyword arguments supplied via *note
     callback_kwargs: 310f.


File: python.info,  Node: Raising errors in a callback,  Next: Callback example 1 trivial callback,  Prev: How callbacks are called,  Up: Option Callbacks

5.17.2.33 Raising errors in a callback
......................................

The callback function should raise *note OptionValueError: 30cb. if
there are any problems with the option or its argument(s).  ‘optparse’
catches this and terminates the program, printing the error message you
supply to stderr.  Your message should be clear, concise, accurate, and
mention the option at fault.  Otherwise, the user will have a hard time
figuring out what they did wrong.


File: python.info,  Node: Callback example 1 trivial callback,  Next: Callback example 2 check option order,  Prev: Raising errors in a callback,  Up: Option Callbacks

5.17.2.34 Callback example 1: trivial callback
..............................................

Here’s an example of a callback option that takes no arguments, and
simply records that the option was seen:

     def record_foo_seen(option, opt_str, value, parser):
         parser.values.saw_foo = True

     parser.add_option("--foo", action="callback", callback=record_foo_seen)

Of course, you could do that with the ‘"store_true"’ action.


File: python.info,  Node: Callback example 2 check option order,  Next: Callback example 3 check option order generalized,  Prev: Callback example 1 trivial callback,  Up: Option Callbacks

5.17.2.35 Callback example 2: check option order
................................................

Here’s a slightly more interesting example: record the fact that ‘-a’ is
seen, but blow up if it comes after ‘-b’ in the command-line.

     def check_order(option, opt_str, value, parser):
         if parser.values.b:
             raise OptionValueError("can't use -a after -b")
         parser.values.a = 1
     ...
     parser.add_option("-a", action="callback", callback=check_order)
     parser.add_option("-b", action="store_true", dest="b")


File: python.info,  Node: Callback example 3 check option order generalized,  Next: Callback example 4 check arbitrary condition,  Prev: Callback example 2 check option order,  Up: Option Callbacks

5.17.2.36 Callback example 3: check option order (generalized)
..............................................................

If you want to reuse this callback for several similar options (set a
flag, but blow up if ‘-b’ has already been seen), it needs a bit of
work: the error message and the flag that it sets must be generalized.

     def check_order(option, opt_str, value, parser):
         if parser.values.b:
             raise OptionValueError("can't use %s after -b" % opt_str)
         setattr(parser.values, option.dest, 1)
     ...
     parser.add_option("-a", action="callback", callback=check_order, dest='a')
     parser.add_option("-b", action="store_true", dest="b")
     parser.add_option("-c", action="callback", callback=check_order, dest='c')


File: python.info,  Node: Callback example 4 check arbitrary condition,  Next: Callback example 5 fixed arguments,  Prev: Callback example 3 check option order generalized,  Up: Option Callbacks

5.17.2.37 Callback example 4: check arbitrary condition
.......................................................

Of course, you could put any condition in there—you’re not limited to
checking the values of already-defined options.  For example, if you
have options that should not be called when the moon is full, all you
have to do is this:

     def check_moon(option, opt_str, value, parser):
         if is_moon_full():
             raise OptionValueError("%s option invalid when moon is full"
                                    % opt_str)
         setattr(parser.values, option.dest, 1)
     ...
     parser.add_option("--foo",
                       action="callback", callback=check_moon, dest="foo")

(The definition of ‘is_moon_full()’ is left as an exercise for the
reader.)


File: python.info,  Node: Callback example 5 fixed arguments,  Next: Callback example 6 variable arguments,  Prev: Callback example 4 check arbitrary condition,  Up: Option Callbacks

5.17.2.38 Callback example 5: fixed arguments
.............................................

Things get slightly more interesting when you define callback options
that take a fixed number of arguments.  Specifying that a callback
option takes arguments is similar to defining a ‘"store"’ or ‘"append"’
option: if you define *note type: 30dc, then the option takes one
argument that must be convertible to that type; if you further define
*note nargs: 310b, then the option takes ‘nargs’ arguments.

Here’s an example that just emulates the standard ‘"store"’ action:

     def store_value(option, opt_str, value, parser):
         setattr(parser.values, option.dest, value)
     ...
     parser.add_option("--foo",
                       action="callback", callback=store_value,
                       type="int", nargs=3, dest="foo")

Note that ‘optparse’ takes care of consuming 3 arguments and converting
them to integers for you; all you have to do is store them.  (Or
whatever; obviously you don’t need a callback for this example.)


File: python.info,  Node: Callback example 6 variable arguments,  Prev: Callback example 5 fixed arguments,  Up: Option Callbacks

5.17.2.39 Callback example 6: variable arguments
................................................

Things get hairy when you want an option to take a variable number of
arguments.  For this case, you must write a callback, as ‘optparse’
doesn’t provide any built-in capabilities for it.  And you have to deal
with certain intricacies of conventional Unix command-line parsing that
‘optparse’ normally handles for you.  In particular, callbacks should
implement the conventional rules for bare ‘--’ and ‘-’ arguments:

   * either ‘--’ or ‘-’ can be option arguments

   * bare ‘--’ (if not the argument to some option): halt command-line
     processing and discard the ‘--’

   * bare ‘-’ (if not the argument to some option): halt command-line
     processing but keep the ‘-’ (append it to ‘parser.largs’)

If you want an option that takes a variable number of arguments, there
are several subtle, tricky issues to worry about.  The exact
implementation you choose will be based on which trade-offs you’re
willing to make for your application (which is why ‘optparse’ doesn’t
support this sort of thing directly).

Nevertheless, here’s a stab at a callback for an option with variable
arguments:

     def vararg_callback(option, opt_str, value, parser):
         assert value is None
         value = []

         def floatable(str):
             try:
                 float(str)
                 return True
             except ValueError:
                 return False

         for arg in parser.rargs:
             # stop on --foo like options
             if arg[:2] == "--" and len(arg) > 2:
                 break
             # stop on -a, but not on -3 or -3.0
             if arg[:1] == "-" and len(arg) > 1 and not floatable(arg):
                 break
             value.append(arg)

         del parser.rargs[:len(value)]
         setattr(parser.values, option.dest, value)

     ...
     parser.add_option("-c", "--callback", dest="vararg_attr",
                       action="callback", callback=vararg_callback)


File: python.info,  Node: Extending optparse,  Next: Exceptions<10>,  Prev: Option Callbacks,  Up: optparse — Parser for command line options

5.17.2.40 Extending ‘optparse’
..............................

Since the two major controlling factors in how ‘optparse’ interprets
command-line options are the action and type of each option, the most
likely direction of extension is to add new actions and new types.

* Menu:

* Adding new types::
* Adding new actions::


File: python.info,  Node: Adding new types,  Next: Adding new actions,  Up: Extending optparse

5.17.2.41 Adding new types
..........................

To add new types, you need to define your own subclass of ‘optparse’’s
*note Option: 3103. class.  This class has a couple of attributes that
define ‘optparse’’s types: *note TYPES: 3138. and *note TYPE_CHECKER:
3139.

 -- Attribute: Option.TYPES

     A tuple of type names; in your subclass, simply define a new tuple
     *note TYPES: 3138. that builds on the standard one.

 -- Attribute: Option.TYPE_CHECKER

     A dictionary mapping type names to type-checking functions.  A
     type-checking function has the following signature:

          def check_mytype(option, opt, value)

     where ‘option’ is an *note Option: 3103. instance, ‘opt’ is an
     option string (e.g., ‘-f’), and ‘value’ is the string from the
     command line that must be checked and converted to your desired
     type.  ‘check_mytype()’ should return an object of the hypothetical
     type ‘mytype’.  The value returned by a type-checking function will
     wind up in the OptionValues instance returned by *note
     OptionParser.parse_args(): 151d, or be passed to a callback as the
     ‘value’ parameter.

     Your type-checking function should raise *note OptionValueError:
     30cb. if it encounters any problems.  ‘OptionValueError’ takes a
     single string argument, which is passed as-is to *note
     OptionParser: 151c.’s ‘error()’ method, which in turn prepends the
     program name and the string ‘"error:"’ and prints everything to
     stderr before terminating the process.

Here’s a silly example that demonstrates adding a ‘"complex"’ option
type to parse Python-style complex numbers on the command line.  (This
is even sillier than it used to be, because ‘optparse’ 1.3 added
built-in support for complex numbers, but never mind.)

First, the necessary imports:

     from copy import copy
     from optparse import Option, OptionValueError

You need to define your type-checker first, since it’s referred to later
(in the *note TYPE_CHECKER: 3139. class attribute of your Option
subclass):

     def check_complex(option, opt, value):
         try:
             return complex(value)
         except ValueError:
             raise OptionValueError(
                 "option %s: invalid complex value: %r" % (opt, value))

Finally, the Option subclass:

     class MyOption (Option):
         TYPES = Option.TYPES + ("complex",)
         TYPE_CHECKER = copy(Option.TYPE_CHECKER)
         TYPE_CHECKER["complex"] = check_complex

(If we didn’t make a *note copy(): 25. of *note Option.TYPE_CHECKER:
3139, we would end up modifying the ‘TYPE_CHECKER’ attribute of
‘optparse’’s Option class.  This being Python, nothing stops you from
doing that except good manners and common sense.)

That’s it!  Now you can write a script that uses the new option type
just like any other ‘optparse’-based script, except you have to instruct
your OptionParser to use MyOption instead of Option:

     parser = OptionParser(option_class=MyOption)
     parser.add_option("-c", type="complex")

Alternately, you can build your own option list and pass it to
OptionParser; if you don’t use ‘add_option()’ in the above way, you
don’t need to tell OptionParser which option class to use:

     option_list = [MyOption("-c", action="store", type="complex", dest="c")]
     parser = OptionParser(option_list=option_list)


File: python.info,  Node: Adding new actions,  Prev: Adding new types,  Up: Extending optparse

5.17.2.42 Adding new actions
............................

Adding new actions is a bit trickier, because you have to understand
that ‘optparse’ has a couple of classifications for actions:

“store” actions

     actions that result in ‘optparse’ storing a value to an attribute
     of the current OptionValues instance; these options require a *note
     dest: 30dd. attribute to be supplied to the Option constructor.

“typed” actions

     actions that take a value from the command line and expect it to be
     of a certain type; or rather, a string that can be converted to a
     certain type.  These options require a *note type: 30dc. attribute
     to the Option constructor.

These are overlapping sets: some default “store” actions are ‘"store"’,
‘"store_const"’, ‘"append"’, and ‘"count"’, while the default “typed”
actions are ‘"store"’, ‘"append"’, and ‘"callback"’.

When you add an action, you need to categorize it by listing it in at
least one of the following class attributes of Option (all are lists of
strings):

 -- Attribute: Option.ACTIONS

     All actions must be listed in ACTIONS.

 -- Attribute: Option.STORE_ACTIONS

     “store” actions are additionally listed here.

 -- Attribute: Option.TYPED_ACTIONS

     “typed” actions are additionally listed here.

 -- Attribute: Option.ALWAYS_TYPED_ACTIONS

     Actions that always take a type (i.e.  whose options always take a
     value) are additionally listed here.  The only effect of this is
     that ‘optparse’ assigns the default type, ‘"string"’, to options
     with no explicit type whose action is listed in *note
     ALWAYS_TYPED_ACTIONS: 313f.

In order to actually implement your new action, you must override
Option’s ‘take_action()’ method and add a case that recognizes your
action.

For example, let’s add an ‘"extend"’ action.  This is similar to the
standard ‘"append"’ action, but instead of taking a single value from
the command-line and appending it to an existing list, ‘"extend"’ will
take multiple values in a single comma-delimited string, and extend an
existing list with them.  That is, if ‘--names’ is an ‘"extend"’ option
of type ‘"string"’, the command line

     --names=foo,bar --names blah --names ding,dong

would result in a list

     ["foo", "bar", "blah", "ding", "dong"]

Again we define a subclass of Option:

     class MyOption(Option):

         ACTIONS = Option.ACTIONS + ("extend",)
         STORE_ACTIONS = Option.STORE_ACTIONS + ("extend",)
         TYPED_ACTIONS = Option.TYPED_ACTIONS + ("extend",)
         ALWAYS_TYPED_ACTIONS = Option.ALWAYS_TYPED_ACTIONS + ("extend",)

         def take_action(self, action, dest, opt, value, values, parser):
             if action == "extend":
                 lvalue = value.split(",")
                 values.ensure_value(dest, []).extend(lvalue)
             else:
                 Option.take_action(
                     self, action, dest, opt, value, values, parser)

Features of note:

   * ‘"extend"’ both expects a value on the command-line and stores that
     value somewhere, so it goes in both *note STORE_ACTIONS: 313d. and
     *note TYPED_ACTIONS: 313e.

   * to ensure that ‘optparse’ assigns the default type of ‘"string"’ to
     ‘"extend"’ actions, we put the ‘"extend"’ action in *note
     ALWAYS_TYPED_ACTIONS: 313f. as well.

   * ‘MyOption.take_action()’ implements just this one new action, and
     passes control back to ‘Option.take_action()’ for the standard
     ‘optparse’ actions.

   * ‘values’ is an instance of the optparse_parser.Values class, which
     provides the very useful ‘ensure_value()’ method.  ‘ensure_value()’
     is essentially *note getattr(): bf0. with a safety valve; it is
     called as

          values.ensure_value(attr, value)

     If the ‘attr’ attribute of ‘values’ doesn’t exist or is ‘None’,
     then ensure_value() first sets it to ‘value’, and then returns
     ‘value’.  This is very handy for actions like ‘"extend"’,
     ‘"append"’, and ‘"count"’, all of which accumulate data in a
     variable and expect that variable to be of a certain type (a list
     for the first two, an integer for the latter).  Using
     ‘ensure_value()’ means that scripts using your action don’t have to
     worry about setting a default value for the option destinations in
     question; they can just leave the default as ‘None’ and
     ‘ensure_value()’ will take care of getting it right when it’s
     needed.


File: python.info,  Node: Exceptions<10>,  Prev: Extending optparse,  Up: optparse — Parser for command line options

5.17.2.43 Exceptions
....................

 -- Exception: optparse.OptionError

     Raised if an *note Option: 3103. instance is created with invalid
     or inconsistent arguments.

 -- Exception: optparse.OptionConflictError

     Raised if conflicting options are added to an *note OptionParser:
     151c.

 -- Exception: optparse.OptionValueError

     Raised if an invalid option value is encountered on the command
     line.

 -- Exception: optparse.BadOptionError

     Raised if an invalid option is passed on the command line.

 -- Exception: optparse.AmbiguousOptionError

     Raised if an ambiguous option is passed on the command line.


File: python.info,  Node: getpass — Portable password input,  Next: fileinput — Iterate over lines from multiple input streams,  Prev: optparse — Parser for command line options,  Up: Command-line interface libraries

5.17.3 ‘getpass’ — Portable password input
------------------------------------------

'Source code:' Lib/getpass.py(1)

__________________________________________________________________

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The ‘getpass’ module provides two functions:

 -- Function: getpass.getpass (prompt='Password: ', stream=None)

     Prompt the user for a password without echoing.  The user is
     prompted using the string 'prompt', which defaults to ‘'Password:
     '’.  On Unix, the prompt is written to the file-like object
     'stream' using the replace error handler if needed.  'stream'
     defaults to the controlling terminal (‘/dev/tty’) or if that is
     unavailable to ‘sys.stderr’ (this argument is ignored on Windows).

     If echo free input is unavailable getpass() falls back to printing
     a warning message to 'stream' and reading from ‘sys.stdin’ and
     issuing a *note GetPassWarning: 3147.

          Note: If you call getpass from within IDLE, the input may be
          done in the terminal you launched IDLE from rather than the
          idle window itself.

 -- Exception: getpass.GetPassWarning

     A *note UserWarning: 246d. subclass issued when password input may
     be echoed.

 -- Function: getpass.getuser ()

     Return the “login name” of the user.

     This function checks the environment variables ‘LOGNAME’, ‘USER’,
     ‘LNAME’ and ‘USERNAME’, in order, and returns the value of the
     first one which is set to a non-empty string.  If none are set, the
     login name from the password database is returned on systems which
     support the *note pwd: b2. module, otherwise, an *note OSError:
     41a. is raised.

     In general, this function should be preferred over *note
     os.getlogin(): 1633.

     Changed in version 3.13: Previously, various exceptions beyond just
     *note OSError: 41a. were raised.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/getpass.py


File: python.info,  Node: fileinput — Iterate over lines from multiple input streams,  Next: curses — Terminal handling for character-cell displays,  Prev: getpass — Portable password input,  Up: Command-line interface libraries

5.17.4 ‘fileinput’ — Iterate over lines from multiple input streams
-------------------------------------------------------------------

'Source code:' Lib/fileinput.py(1)

__________________________________________________________________

This module implements a helper class and functions to quickly write a
loop over standard input or a list of files.  If you just want to read
or write one file see *note open(): 51f.

The typical use is:

     import fileinput
     for line in fileinput.input(encoding="utf-8"):
         process(line)

This iterates over the lines of all files listed in ‘sys.argv[1:]’,
defaulting to ‘sys.stdin’ if the list is empty.  If a filename is ‘'-'’,
it is also replaced by ‘sys.stdin’ and the optional arguments 'mode' and
'openhook' are ignored.  To specify an alternative list of filenames,
pass it as the first argument to *note input(): 805.  A single file name
is also allowed.

All files are opened in text mode by default, but you can override this
by specifying the 'mode' parameter in the call to *note input(): 805. or
*note FileInput: 73a.  If an I/O error occurs during opening or reading
a file, *note OSError: 41a. is raised.

Changed in version 3.3: *note IOError: 1090. used to be raised; it is
now an alias of *note OSError: 41a.

If ‘sys.stdin’ is used more than once, the second and further use will
return no lines, except perhaps for interactive use, or if it has been
explicitly reset (e.g.  using ‘sys.stdin.seek(0)’).

Empty files are opened and immediately closed; the only time their
presence in the list of filenames is noticeable at all is when the last
file opened is empty.

Lines are returned with any newlines intact, which means that the last
line in a file may not have one.

You can control how files are opened by providing an opening hook via
the 'openhook' parameter to *note fileinput.input(): 805. or *note
FileInput(): 73a.  The hook must be a function that takes two arguments,
'filename' and 'mode', and returns an accordingly opened file-like
object.  If 'encoding' and/or 'errors' are specified, they will be
passed to the hook as additional keyword arguments.  This module
provides a *note hook_compressed(): 806. to support compressed files.

The following function is the primary interface of this module:

 -- Function: fileinput.input (files=None, inplace=False, backup='', *,
          mode='r', openhook=None, encoding=None, errors=None)

     Create an instance of the *note FileInput: 73a. class.  The
     instance will be used as global state for the functions of this
     module, and is also returned to use during iteration.  The
     parameters to this function will be passed along to the constructor
     of the ‘FileInput’ class.

     The *note FileInput: 73a. instance can be used as a context manager
     in the *note with: 5d5. statement.  In this example, 'input' is
     closed after the ‘with’ statement is exited, even if an exception
     occurs:

          with fileinput.input(files=('spam.txt', 'eggs.txt'), encoding="utf-8") as f:
              for line in f:
                  process(line)

     Changed in version 3.2: Can be used as a context manager.

     Changed in version 3.8: The keyword parameters 'mode' and
     'openhook' are now keyword-only.

     Changed in version 3.10: The keyword-only parameter 'encoding' and
     'errors' are added.

The following functions use the global state created by *note
fileinput.input(): 805.; if there is no active state, *note
RuntimeError: 195. is raised.

 -- Function: fileinput.filename ()

     Return the name of the file currently being read.  Before the first
     line has been read, returns ‘None’.

 -- Function: fileinput.fileno ()

     Return the integer “file descriptor” for the current file.  When no
     file is opened (before the first line and between files), returns
     ‘-1’.

 -- Function: fileinput.lineno ()

     Return the cumulative line number of the line that has just been
     read.  Before the first line has been read, returns ‘0’.  After the
     last line of the last file has been read, returns the line number
     of that line.

 -- Function: fileinput.filelineno ()

     Return the line number in the current file.  Before the first line
     has been read, returns ‘0’.  After the last line of the last file
     has been read, returns the line number of that line within the
     file.

 -- Function: fileinput.isfirstline ()

     Return ‘True’ if the line just read is the first line of its file,
     otherwise return ‘False’.

 -- Function: fileinput.isstdin ()

     Return ‘True’ if the last line was read from ‘sys.stdin’, otherwise
     return ‘False’.

 -- Function: fileinput.nextfile ()

     Close the current file so that the next iteration will read the
     first line from the next file (if any); lines not read from the
     file will not count towards the cumulative line count.  The
     filename is not changed until after the first line of the next file
     has been read.  Before the first line has been read, this function
     has no effect; it cannot be used to skip the first file.  After the
     last line of the last file has been read, this function has no
     effect.

 -- Function: fileinput.close ()

     Close the sequence.

The class which implements the sequence behavior provided by the module
is available for subclassing as well:

 -- Class: fileinput.FileInput (files=None, inplace=False, backup='', *,
          mode='r', openhook=None, encoding=None, errors=None)

     Class ‘FileInput’ is the implementation; its methods *note
     filename(): 314b, *note fileno(): 147c, *note lineno(): 314c, *note
     filelineno(): 314d, *note isfirstline(): 314e, *note isstdin():
     314f, *note nextfile(): 3150. and *note close(): 3151. correspond
     to the functions of the same name in the module.  In addition it is
     *note iterable: 126d. and has a *note readline(): 1e5e. method
     which returns the next input line.  The sequence must be accessed
     in strictly sequential order; random access and ‘readline()’ cannot
     be mixed.

     With 'mode' you can specify which file mode will be passed to *note
     open(): 51f.  It must be one of ‘'r'’ and ‘'rb'’.

     The 'openhook', when given, must be a function that takes two
     arguments, 'filename' and 'mode', and returns an accordingly opened
     file-like object.  You cannot use 'inplace' and 'openhook'
     together.

     You can specify 'encoding' and 'errors' that is passed to *note
     open(): 51f. or 'openhook'.

     A ‘FileInput’ instance can be used as a context manager in the
     *note with: 5d5. statement.  In this example, 'input' is closed
     after the ‘with’ statement is exited, even if an exception occurs:

          with FileInput(files=('spam.txt', 'eggs.txt')) as input:
              process(input)

     Changed in version 3.2: Can be used as a context manager.

     Changed in version 3.8: The keyword parameter 'mode' and 'openhook'
     are now keyword-only.

     Changed in version 3.10: The keyword-only parameter 'encoding' and
     'errors' are added.

     Changed in version 3.11: The ‘'rU'’ and ‘'U'’ modes and the
     ‘__getitem__()’ method have been removed.

'Optional in-place filtering:' if the keyword argument ‘inplace=True’ is
passed to *note fileinput.input(): 805. or to the *note FileInput: 73a.
constructor, the file is moved to a backup file and standard output is
directed to the input file (if a file of the same name as the backup
file already exists, it will be replaced silently).  This makes it
possible to write a filter that rewrites its input file in place.  If
the 'backup' parameter is given (typically as ‘backup='.<some
extension>'’), it specifies the extension for the backup file, and the
backup file remains around; by default, the extension is ‘'.bak'’ and it
is deleted when the output file is closed.  In-place filtering is
disabled when standard input is read.

The two following opening hooks are provided by this module:

 -- Function: fileinput.hook_compressed (filename, mode, *,
          encoding=None, errors=None)

     Transparently opens files compressed with gzip and bzip2
     (recognized by the extensions ‘'.gz'’ and ‘'.bz2'’) using the *note
     gzip: 67. and *note bz2: 13. modules.  If the filename extension is
     not ‘'.gz'’ or ‘'.bz2'’, the file is opened normally (ie, using
     *note open(): 51f. without any decompression).

     The 'encoding' and 'errors' values are passed to *note
     io.TextIOWrapper: 7bf. for compressed files and open for normal
     files.

     Usage example: ‘fi =
     fileinput.FileInput(openhook=fileinput.hook_compressed,
     encoding="utf-8")’

     Changed in version 3.10: The keyword-only parameter 'encoding' and
     'errors' are added.

 -- Function: fileinput.hook_encoded (encoding, errors=None)

     Returns a hook which opens each file with *note open(): 51f, using
     the given 'encoding' and 'errors' to read the file.

     Usage example: ‘fi =
     fileinput.FileInput(openhook=fileinput.hook_encoded("utf-8",
     "surrogateescape"))’

     Changed in version 3.6: Added the optional 'errors' parameter.

     Deprecated since version 3.10: This function is deprecated since
     *note fileinput.input(): 805. and *note FileInput: 73a. now have
     'encoding' and 'errors' parameters.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/fileinput.py


File: python.info,  Node: curses — Terminal handling for character-cell displays,  Next: curses textpad — Text input widget for curses programs,  Prev: fileinput — Iterate over lines from multiple input streams,  Up: Command-line interface libraries

5.17.5 ‘curses’ — Terminal handling for character-cell displays
---------------------------------------------------------------

'Source code:' Lib/curses(1)

__________________________________________________________________

The ‘curses’ module provides an interface to the curses library, the
de-facto standard for portable advanced terminal handling.

While curses is most widely used in the Unix environment, versions are
available for Windows, DOS, and possibly other systems as well.  This
extension module is designed to match the API of ncurses, an open-source
curses library hosted on Linux and the BSD variants of Unix.

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

*note Availability: 1ef7.: Unix.

     Note: Whenever the documentation mentions a 'character' it can be
     specified as an integer, a one-character Unicode string or a
     one-byte byte string.

     Whenever the documentation mentions a 'character string' it can be
     specified as a Unicode string or a byte string.

See also
........

Module *note curses.ascii: 2c.

     Utilities for working with ASCII characters, regardless of your
     locale settings.

Module *note curses.panel: 2d.

     A panel stack extension that adds depth to curses windows.

Module *note curses.textpad: 2e.

     Editable text widget for curses supporting ‘Emacs’-like bindings.

*note Curses Programming with Python: 3155.

     Tutorial material on using curses with Python, by Andrew Kuchling
     and Eric Raymond.

* Menu:

* Functions: Functions<6>.
* Window Objects::
* Constants: Constants<6>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/curses


File: python.info,  Node: Functions<6>,  Next: Window Objects,  Up: curses — Terminal handling for character-cell displays

5.17.5.1 Functions
..................

The module ‘curses’ defines the following exception:

 -- Exception: curses.error

     Exception raised when a curses library function returns an error.

     Note: Whenever 'x' or 'y' arguments to a function or a method are
     optional, they default to the current cursor location.  Whenever
     'attr' is optional, it defaults to *note A_NORMAL: 3159.

The module ‘curses’ defines the following functions:

 -- Function: curses.baudrate ()

     Return the output speed of the terminal in bits per second.  On
     software terminal emulators it will have a fixed high value.
     Included for historical reasons; in former times, it was used to
     write output loops for time delays and occasionally to change
     interfaces depending on the line speed.

 -- Function: curses.beep ()

     Emit a short attention sound.

 -- Function: curses.can_change_color ()

     Return ‘True’ or ‘False’, depending on whether the programmer can
     change the colors displayed by the terminal.

 -- Function: curses.cbreak ()

     Enter cbreak mode.  In cbreak mode (sometimes called “rare” mode)
     normal tty line buffering is turned off and characters are
     available to be read one by one.  However, unlike raw mode, special
     characters (interrupt, quit, suspend, and flow control) retain
     their effects on the tty driver and calling program.  Calling first
     *note raw(): 315e. then ‘cbreak()’ leaves the terminal in cbreak
     mode.

 -- Function: curses.color_content (color_number)

     Return the intensity of the red, green, and blue (RGB) components
     in the color 'color_number', which must be between ‘0’ and ‘COLORS
     - 1’.  Return a 3-tuple, containing the R,G,B values for the given
     color, which will be between ‘0’ (no component) and ‘1000’ (maximum
     amount of component).

 -- Function: curses.color_pair (pair_number)

     Return the attribute value for displaying text in the specified
     color pair.  Only the first 256 color pairs are supported.  This
     attribute value can be combined with *note A_STANDOUT: 3160, *note
     A_REVERSE: 3161, and the other ‘A_*’ attributes.  *note
     pair_number(): 3162. is the counterpart to this function.

 -- Function: curses.curs_set (visibility)

     Set the cursor state.  'visibility' can be set to ‘0’, ‘1’, or ‘2’,
     for invisible, normal, or very visible.  If the terminal supports
     the visibility requested, return the previous cursor state;
     otherwise raise an exception.  On many terminals, the “visible”
     mode is an underline cursor and the “very visible” mode is a block
     cursor.

 -- Function: curses.def_prog_mode ()

     Save the current terminal mode as the “program” mode, the mode when
     the running program is using curses.  (Its counterpart is the
     “shell” mode, for when the program is not in curses.)  Subsequent
     calls to *note reset_prog_mode(): 3165. will restore this mode.

 -- Function: curses.def_shell_mode ()

     Save the current terminal mode as the “shell” mode, the mode when
     the running program is not using curses.  (Its counterpart is the
     “program” mode, when the program is using curses capabilities.)
     Subsequent calls to *note reset_shell_mode(): 3167. will restore
     this mode.

 -- Function: curses.delay_output (ms)

     Insert an 'ms' millisecond pause in output.

 -- Function: curses.doupdate ()

     Update the physical screen.  The curses library keeps two data
     structures, one representing the current physical screen contents
     and a virtual screen representing the desired next state.  The
     ‘doupdate()’ ground updates the physical screen to match the
     virtual screen.

     The virtual screen may be updated by a *note noutrefresh(): 316a.
     call after write operations such as *note addstr(): 316b. have been
     performed on a window.  The normal *note refresh(): 316c. call is
     simply ‘noutrefresh()’ followed by ‘doupdate()’; if you have to
     update multiple windows, you can speed performance and perhaps
     reduce screen flicker by issuing ‘noutrefresh()’ calls on all
     windows, followed by a single ‘doupdate()’.

 -- Function: curses.echo ()

     Enter echo mode.  In echo mode, each character input is echoed to
     the screen as it is entered.

 -- Function: curses.endwin ()

     De-initialize the library, and return terminal to normal status.

 -- Function: curses.erasechar ()

     Return the user’s current erase character as a one-byte bytes
     object.  Under Unix operating systems this is a property of the
     controlling tty of the curses program, and is not set by the curses
     library itself.

 -- Function: curses.filter ()

     The ‘filter()’ routine, if used, must be called before *note
     initscr(): 16a7. is called.  The effect is that, during those
     calls, ‘LINES’ is set to ‘1’; the capabilities ‘clear’, ‘cup’,
     ‘cud’, ‘cud1’, ‘cuu1’, ‘cuu’, ‘vpa’ are disabled; and the ‘home’
     string is set to the value of ‘cr’.  The effect is that the cursor
     is confined to the current line, and so are screen updates.  This
     may be used for enabling character-at-a-time line editing without
     touching the rest of the screen.

 -- Function: curses.flash ()

     Flash the screen.  That is, change it to reverse-video and then
     change it back in a short interval.  Some people prefer such as
     ‘visible bell’ to the audible attention signal produced by *note
     beep(): 315b.

 -- Function: curses.flushinp ()

     Flush all input buffers.  This throws away any typeahead that has
     been typed by the user and has not yet been processed by the
     program.

 -- Function: curses.getmouse ()

     After *note getch(): 1647. returns *note KEY_MOUSE: 3174. to signal
     a mouse event, this method should be called to retrieve the queued
     mouse event, represented as a 5-tuple ‘(id, x, y, z, bstate)’.
     'id' is an ID value used to distinguish multiple devices, and 'x',
     'y', 'z' are the event’s coordinates.  ('z' is currently unused.)
     'bstate' is an integer value whose bits will be set to indicate the
     type of event, and will be the bitwise OR of one or more of the
     following constants, where 'n' is the button number from 1 to 5:
     *note BUTTONn_PRESSED: 3175, *note BUTTONn_RELEASED: 3176, *note
     BUTTONn_CLICKED: 3177, *note BUTTONn_DOUBLE_CLICKED: 3178, *note
     BUTTONn_TRIPLE_CLICKED: 3179, *note BUTTON_SHIFT: 317a, *note
     BUTTON_CTRL: 317b, *note BUTTON_ALT: 317c.

     Changed in version 3.10: The ‘BUTTON5_*’ constants are now exposed
     if they are provided by the underlying curses library.

 -- Function: curses.getsyx ()

     Return the current coordinates of the virtual screen cursor as a
     tuple ‘(y, x)’.  If *note leaveok: 317e. is currently ‘True’, then
     return ‘(-1, -1)’.

 -- Function: curses.getwin (file)

     Read window related data stored in the file by an earlier *note
     window.putwin(): 3180. call.  The routine then creates and
     initializes a new window using that data, returning the new window
     object.

 -- Function: curses.has_colors ()

     Return ‘True’ if the terminal can display colors; otherwise, return
     ‘False’.

 -- Function: curses.has_extended_color_support ()

     Return ‘True’ if the module supports extended colors; otherwise,
     return ‘False’.  Extended color support allows more than 256 color
     pairs for terminals that support more than 16 colors (e.g.
     xterm-256color).

     Extended color support requires ncurses version 6.1 or later.

     Added in version 3.10.

 -- Function: curses.has_ic ()

     Return ‘True’ if the terminal has insert- and delete-character
     capabilities.  This function is included for historical reasons
     only, as all modern software terminal emulators have such
     capabilities.

 -- Function: curses.has_il ()

     Return ‘True’ if the terminal has insert- and delete-line
     capabilities, or can simulate them using scrolling regions.  This
     function is included for historical reasons only, as all modern
     software terminal emulators have such capabilities.

 -- Function: curses.has_key (ch)

     Take a key value 'ch', and return ‘True’ if the current terminal
     type recognizes a key with that value.

 -- Function: curses.halfdelay (tenths)

     Used for half-delay mode, which is similar to cbreak mode in that
     characters typed by the user are immediately available to the
     program.  However, after blocking for 'tenths' tenths of seconds,
     raise an exception if nothing has been typed.  The value of
     'tenths' must be a number between ‘1’ and ‘255’.  Use *note
     nocbreak(): 3186. to leave half-delay mode.

 -- Function: curses.init_color (color_number, r, g, b)

     Change the definition of a color, taking the number of the color to
     be changed followed by three RGB values (for the amounts of red,
     green, and blue components).  The value of 'color_number' must be
     between ‘0’ and ‘COLORS - 1’.  Each of 'r', 'g', 'b', must be a
     value between ‘0’ and ‘1000’.  When ‘init_color()’ is used, all
     occurrences of that color on the screen immediately change to the
     new definition.  This function is a no-op on most terminals; it is
     active only if *note can_change_color(): 315c. returns ‘True’.

 -- Function: curses.init_pair (pair_number, fg, bg)

     Change the definition of a color-pair.  It takes three arguments:
     the number of the color-pair to be changed, the foreground color
     number, and the background color number.  The value of
     'pair_number' must be between ‘1’ and ‘COLOR_PAIRS - 1’ (the ‘0’
     color pair is wired to white on black and cannot be changed).  The
     value of 'fg' and 'bg' arguments must be between ‘0’ and ‘COLORS -
     1’, or, after calling *note use_default_colors(): 3187, ‘-1’.  If
     the color-pair was previously initialized, the screen is refreshed
     and all occurrences of that color-pair are changed to the new
     definition.

 -- Function: curses.initscr ()

     Initialize the library.  Return a *note window: 3188. object which
     represents the whole screen.

          Note: If there is an error opening the terminal, the
          underlying curses library may cause the interpreter to exit.

 -- Function: curses.is_term_resized (nlines, ncols)

     Return ‘True’ if *note resize_term(): 16af. would modify the window
     structure, ‘False’ otherwise.

 -- Function: curses.isendwin ()

     Return ‘True’ if *note endwin(): 316e. has been called (that is,
     the curses library has been deinitialized).

 -- Function: curses.keyname (k)

     Return the name of the key numbered 'k' as a bytes object.  The
     name of a key generating printable ASCII character is the key’s
     character.  The name of a control-key combination is a two-byte
     bytes object consisting of a caret (‘b'^'’) followed by the
     corresponding printable ASCII character.  The name of an alt-key
     combination (128–255) is a bytes object consisting of the prefix
     ‘b'M-'’ followed by the name of the corresponding ASCII character.

 -- Function: curses.killchar ()

     Return the user’s current line kill character as a one-byte bytes
     object.  Under Unix operating systems this is a property of the
     controlling tty of the curses program, and is not set by the curses
     library itself.

 -- Function: curses.longname ()

     Return a bytes object containing the terminfo long name field
     describing the current terminal.  The maximum length of a verbose
     description is 128 characters.  It is defined only after the call
     to *note initscr(): 16a7.

 -- Function: curses.meta (flag)

     If 'flag' is ‘True’, allow 8-bit characters to be input.  If 'flag'
     is ‘False’, allow only 7-bit chars.

 -- Function: curses.mouseinterval (interval)

     Set the maximum time in milliseconds that can elapse between press
     and release events in order for them to be recognized as a click,
     and return the previous interval value.  The default value is 200
     milliseconds, or one fifth of a second.

 -- Function: curses.mousemask (mousemask)

     Set the mouse events to be reported, and return a tuple
     ‘(availmask, oldmask)’.  'availmask' indicates which of the
     specified mouse events can be reported; on complete failure it
     returns ‘0’.  'oldmask' is the previous value of the given window’s
     mouse event mask.  If this function is never called, no mouse
     events are ever reported.

 -- Function: curses.napms (ms)

     Sleep for 'ms' milliseconds.

 -- Function: curses.newpad (nlines, ncols)

     Create and return a pointer to a new pad data structure with the
     given number of lines and columns.  Return a pad as a window
     object.

     A pad is like a window, except that it is not restricted by the
     screen size, and is not necessarily associated with a particular
     part of the screen.  Pads can be used when a large window is
     needed, and only a part of the window will be on the screen at one
     time.  Automatic refreshes of pads (such as from scrolling or
     echoing of input) do not occur.  The *note refresh(): 316c. and
     *note noutrefresh(): 316a. methods of a pad require 6 arguments to
     specify the part of the pad to be displayed and the location on the
     screen to be used for the display.  The arguments are 'pminrow',
     'pmincol', 'sminrow', 'smincol', 'smaxrow', 'smaxcol'; the 'p'
     arguments refer to the upper left corner of the pad region to be
     displayed and the 's' arguments define a clipping box on the screen
     within which the pad region is to be displayed.

 -- Function: curses.newwin (nlines, ncols)

 -- Function: curses.newwin (nlines, ncols, begin_y, begin_x)

     Return a new *note window: 3188, whose left-upper corner is at
     ‘(begin_y, begin_x)’, and whose height/width is 'nlines'/'ncols'.

     By default, the window will extend from the specified position to
     the lower right corner of the screen.

 -- Function: curses.nl ()

     Enter newline mode.  This mode translates the return key into
     newline on input, and translates newline into return and line-feed
     on output.  Newline mode is initially on.

 -- Function: curses.nocbreak ()

     Leave cbreak mode.  Return to normal “cooked” mode with line
     buffering.

 -- Function: curses.noecho ()

     Leave echo mode.  Echoing of input characters is turned off.

 -- Function: curses.nonl ()

     Leave newline mode.  Disable translation of return into newline on
     input, and disable low-level translation of newline into
     newline/return on output (but this does not change the behavior of
     ‘addch('\n')’, which always does the equivalent of return and line
     feed on the virtual screen).  With translation off, curses can
     sometimes speed up vertical motion a little; also, it will be able
     to detect the return key on input.

 -- Function: curses.noqiflush ()

     When the ‘noqiflush()’ routine is used, normal flush of input and
     output queues associated with the ‘INTR’, ‘QUIT’ and ‘SUSP’
     characters will not be done.  You may want to call ‘noqiflush()’ in
     a signal handler if you want output to continue as though the
     interrupt had not occurred, after the handler exits.

 -- Function: curses.noraw ()

     Leave raw mode.  Return to normal “cooked” mode with line
     buffering.

 -- Function: curses.pair_content (pair_number)

     Return a tuple ‘(fg, bg)’ containing the colors for the requested
     color pair.  The value of 'pair_number' must be between ‘0’ and
     ‘COLOR_PAIRS - 1’.

 -- Function: curses.pair_number (attr)

     Return the number of the color-pair set by the attribute value
     'attr'.  *note color_pair(): 315f. is the counterpart to this
     function.

 -- Function: curses.putp (str)

     Equivalent to ‘tputs(str, 1, putchar)’; emit the value of a
     specified terminfo capability for the current terminal.  Note that
     the output of ‘putp()’ always goes to standard output.

 -- Function: curses.qiflush ([flag])

     If 'flag' is ‘False’, the effect is the same as calling *note
     noqiflush(): 3196.  If 'flag' is ‘True’, or no argument is
     provided, the queues will be flushed when these control characters
     are read.

 -- Function: curses.raw ()

     Enter raw mode.  In raw mode, normal line buffering and processing
     of interrupt, quit, suspend, and flow control keys are turned off;
     characters are presented to curses input functions one by one.

 -- Function: curses.reset_prog_mode ()

     Restore the terminal to “program” mode, as previously saved by
     *note def_prog_mode(): 3164.

 -- Function: curses.reset_shell_mode ()

     Restore the terminal to “shell” mode, as previously saved by *note
     def_shell_mode(): 3166.

 -- Function: curses.resetty ()

     Restore the state of the terminal modes to what it was at the last
     call to *note savetty(): 319b.

 -- Function: curses.resize_term (nlines, ncols)

     Backend function used by *note resizeterm(): 16ae, performing most
     of the work; when resizing the windows, ‘resize_term()’ blank-fills
     the areas that are extended.  The calling application should fill
     in these areas with appropriate data.  The ‘resize_term()’ function
     attempts to resize all windows.  However, due to the calling
     convention of pads, it is not possible to resize these without
     additional interaction with the application.

 -- Function: curses.resizeterm (nlines, ncols)

     Resize the standard and current windows to the specified
     dimensions, and adjusts other bookkeeping data used by the curses
     library that record the window dimensions (in particular the
     SIGWINCH handler).

 -- Function: curses.savetty ()

     Save the current state of the terminal modes in a buffer, usable by
     *note resetty(): 319a.

 -- Function: curses.get_escdelay ()

     Retrieves the value set by *note set_escdelay(): 8fa.

     Added in version 3.9.

 -- Function: curses.set_escdelay (ms)

     Sets the number of milliseconds to wait after reading an escape
     character, to distinguish between an individual escape character
     entered on the keyboard from escape sequences sent by cursor and
     function keys.

     Added in version 3.9.

 -- Function: curses.get_tabsize ()

     Retrieves the value set by *note set_tabsize(): 8fc.

     Added in version 3.9.

 -- Function: curses.set_tabsize (size)

     Sets the number of columns used by the curses library when
     converting a tab character to spaces as it adds the tab to a
     window.

     Added in version 3.9.

 -- Function: curses.setsyx (y, x)

     Set the virtual screen cursor to 'y', 'x'.  If 'y' and 'x' are both
     ‘-1’, then *note leaveok: 317e. is set ‘True’.

 -- Function: curses.setupterm (term=None, fd=-1)

     Initialize the terminal.  'term' is a string giving the terminal
     name, or ‘None’; if omitted or ‘None’, the value of the ‘TERM’
     environment variable will be used.  'fd' is the file descriptor to
     which any initialization sequences will be sent; if not supplied or
     ‘-1’, the file descriptor for ‘sys.stdout’ will be used.

 -- Function: curses.start_color ()

     Must be called if the programmer wants to use colors, and before
     any other color manipulation routine is called.  It is good
     practice to call this routine right after *note initscr(): 16a7.

     ‘start_color()’ initializes eight basic colors (black, red, green,
     yellow, blue, magenta, cyan, and white), and two global variables
     in the ‘curses’ module, *note COLORS: 319f. and *note COLOR_PAIRS:
     31a0, containing the maximum number of colors and color-pairs the
     terminal can support.  It also restores the colors on the terminal
     to the values they had when the terminal was just turned on.

 -- Function: curses.termattrs ()

     Return a logical OR of all video attributes supported by the
     terminal.  This information is useful when a curses program needs
     complete control over the appearance of the screen.

 -- Function: curses.termname ()

     Return the value of the environment variable ‘TERM’, as a bytes
     object, truncated to 14 characters.

 -- Function: curses.tigetflag (capname)

     Return the value of the Boolean capability corresponding to the
     terminfo capability name 'capname' as an integer.  Return the value
     ‘-1’ if 'capname' is not a Boolean capability, or ‘0’ if it is
     canceled or absent from the terminal description.

 -- Function: curses.tigetnum (capname)

     Return the value of the numeric capability corresponding to the
     terminfo capability name 'capname' as an integer.  Return the value
     ‘-2’ if 'capname' is not a numeric capability, or ‘-1’ if it is
     canceled or absent from the terminal description.

 -- Function: curses.tigetstr (capname)

     Return the value of the string capability corresponding to the
     terminfo capability name 'capname' as a bytes object.  Return
     ‘None’ if 'capname' is not a terminfo “string capability”, or is
     canceled or absent from the terminal description.

 -- Function: curses.tparm (str[, ...])

     Instantiate the bytes object 'str' with the supplied parameters,
     where 'str' should be a parameterized string obtained from the
     terminfo database.  E.g.  ‘tparm(tigetstr("cup"), 5, 3)’ could
     result in ‘b'\033[6;4H'’, the exact result depending on terminal
     type.

 -- Function: curses.typeahead (fd)

     Specify that the file descriptor 'fd' be used for typeahead
     checking.  If 'fd' is ‘-1’, then no typeahead checking is done.

     The curses library does “line-breakout optimization” by looking for
     typeahead periodically while updating the screen.  If input is
     found, and it is coming from a tty, the current update is postponed
     until refresh or doupdate is called again, allowing faster response
     to commands typed in advance.  This function allows specifying a
     different file descriptor for typeahead checking.

 -- Function: curses.unctrl (ch)

     Return a bytes object which is a printable representation of the
     character 'ch'.  Control characters are represented as a caret
     followed by the character, for example as ‘b'^C'’.  Printing
     characters are left as they are.

 -- Function: curses.ungetch (ch)

     Push 'ch' so the next *note getch(): 1647. will return it.

          Note: Only one 'ch' can be pushed before ‘getch()’ is called.

 -- Function: curses.update_lines_cols ()

     Update the *note LINES: e1d. and *note COLS: e1e. module variables.
     Useful for detecting manual screen resize.

     Added in version 3.5.

 -- Function: curses.unget_wch (ch)

     Push 'ch' so the next *note get_wch(): 10db. will return it.

          Note: Only one 'ch' can be pushed before ‘get_wch()’ is
          called.

     Added in version 3.3.

 -- Function: curses.ungetmouse (id, x, y, z, bstate)

     Push a *note KEY_MOUSE: 3174. event onto the input queue,
     associating the given state data with it.

 -- Function: curses.use_env (flag)

     If used, this function should be called before *note initscr():
     16a7. or newterm are called.  When 'flag' is ‘False’, the values of
     lines and columns specified in the terminfo database will be used,
     even if environment variables ‘LINES’ and ‘COLUMNS’ (used by
     default) are set, or if curses is running in a window (in which
     case default behavior would be to use the window size if ‘LINES’
     and ‘COLUMNS’ are not set).

 -- Function: curses.use_default_colors ()

     Allow use of default values for colors on terminals supporting this
     feature.  Use this to support transparency in your application.
     The default color is assigned to the color number ‘-1’.  After
     calling this function, ‘init_pair(x, curses.COLOR_RED, -1)’
     initializes, for instance, color pair 'x' to a red foreground color
     on the default background.

 -- Function: curses.wrapper (func, /, *args, **kwargs)

     Initialize curses and call another callable object, 'func', which
     should be the rest of your curses-using application.  If the
     application raises an exception, this function will restore the
     terminal to a sane state before re-raising the exception and
     generating a traceback.  The callable object 'func' is then passed
     the main window ‘stdscr’ as its first argument, followed by any
     other arguments passed to ‘wrapper()’.  Before calling 'func',
     ‘wrapper()’ turns on cbreak mode, turns off echo, enables the
     terminal keypad, and initializes colors if the terminal has color
     support.  On exit (whether normally or by exception) it restores
     cooked mode, turns on echo, and disables the terminal keypad.


File: python.info,  Node: Window Objects,  Next: Constants<6>,  Prev: Functions<6>,  Up: curses — Terminal handling for character-cell displays

5.17.5.2 Window Objects
.......................

 -- Class: curses.window

     Window objects, as returned by *note initscr(): 16a7. and *note
     newwin(): 3192. above, have the following methods and attributes:

 -- Method: window.addch (ch[, attr])

 -- Method: window.addch (y, x, ch[, attr])

     Paint character 'ch' at ‘(y, x)’ with attributes 'attr',
     overwriting any character previously painted at that location.  By
     default, the character position and attributes are the current
     settings for the window object.

          Note: Writing outside the window, subwindow, or pad raises a
          *note curses.error: 3158.  Attempting to write to the lower
          right corner of a window, subwindow, or pad will cause an
          exception to be raised after the character is printed.

 -- Method: window.addnstr (str, n[, attr])

 -- Method: window.addnstr (y, x, str, n[, attr])

     Paint at most 'n' characters of the character string 'str' at ‘(y,
     x)’ with attributes 'attr', overwriting anything previously on the
     display.

 -- Method: window.addstr (str[, attr])

 -- Method: window.addstr (y, x, str[, attr])

     Paint the character string 'str' at ‘(y, x)’ with attributes
     'attr', overwriting anything previously on the display.

          Note: 
             * Writing outside the window, subwindow, or pad raises
               *note curses.error: 3158.  Attempting to write to the
               lower right corner of a window, subwindow, or pad will
               cause an exception to be raised after the string is
               printed.

             * A bug in ncurses(1), the backend for this Python module,
               can cause SegFaults when resizing windows.  This is fixed
               in ncurses-6.1-20190511.  If you are stuck with an
               earlier ncurses, you can avoid triggering this if you do
               not call *note addstr(): 316b. with a 'str' that has
               embedded newlines.  Instead, call ‘addstr()’ separately
               for each line.

 -- Method: window.attroff (attr)

     Remove attribute 'attr' from the “background” set applied to all
     writes to the current window.

 -- Method: window.attron (attr)

     Add attribute 'attr' to the “background” set applied to all writes
     to the current window.

 -- Method: window.attrset (attr)

     Set the “background” set of attributes to 'attr'.  This set is
     initially ‘0’ (no attributes).

 -- Method: window.bkgd (ch[, attr])

     Set the background property of the window to the character 'ch',
     with attributes 'attr'.  The change is then applied to every
     character position in that window:

        * The attribute of every character in the window is changed to
          the new background attribute.

        * Wherever the former background character appears, it is
          changed to the new background character.

 -- Method: window.bkgdset (ch[, attr])

     Set the window’s background.  A window’s background consists of a
     character and any combination of attributes.  The attribute part of
     the background is combined (OR’ed) with all non-blank characters
     that are written into the window.  Both the character and attribute
     parts of the background are combined with the blank characters.
     The background becomes a property of the character and moves with
     the character through any scrolling and insert/delete
     line/character operations.

 -- Method: window.border ([ls[, rs[, ts[, bs[, tl[, tr[, bl[,
          br]]]]]]]])

     Draw a border around the edges of the window.  Each parameter
     specifies the character to use for a specific part of the border;
     see the table below for more details.

          Note: A ‘0’ value for any parameter will cause the default
          character to be used for that parameter.  Keyword parameters
          can 'not' be used.  The defaults are listed in this table:

     Parameter       Description               Default value
                                               
     ----------------------------------------------------------------------
                                               
     'ls'            Left side                 *note ACS_VLINE: 31b5.
                                               
                                               
     'rs'            Right side                *note ACS_VLINE: 31b5.
                                               
                                               
     'ts'            Top                       *note ACS_HLINE: 31b6.
                                               
                                               
     'bs'            Bottom                    *note ACS_HLINE: 31b6.
                                               
                                               
     'tl'            Upper-left corner         *note ACS_ULCORNER: 31b7.
                                               
                                               
     'tr'            Upper-right corner        *note ACS_URCORNER: 31b8.
                                               
                                               
     'bl'            Bottom-left corner        *note ACS_LLCORNER: 31b9.
                                               
                                               
     'br'            Bottom-right corner       *note ACS_LRCORNER: 31ba.
                                               

 -- Method: window.box ([vertch, horch])

     Similar to *note border(): 31b4, but both 'ls' and 'rs' are
     'vertch' and both 'ts' and 'bs' are 'horch'.  The default corner
     characters are always used by this function.

 -- Method: window.chgat (attr)

 -- Method: window.chgat (num, attr)

 -- Method: window.chgat (y, x, attr)

 -- Method: window.chgat (y, x, num, attr)

     Set the attributes of 'num' characters at the current cursor
     position, or at position ‘(y, x)’ if supplied.  If 'num' is not
     given or is ‘-1’, the attribute will be set on all the characters
     to the end of the line.  This function moves cursor to position
     ‘(y, x)’ if supplied.  The changed line will be touched using the
     *note touchline(): 31bd. method so that the contents will be
     redisplayed by the next window refresh.

 -- Method: window.clear ()

     Like *note erase(): 31bf, but also cause the whole window to be
     repainted upon next call to *note refresh(): 316c.

 -- Method: window.clearok (flag)

     If 'flag' is ‘True’, the next call to *note refresh(): 316c. will
     clear the window completely.

 -- Method: window.clrtobot ()

     Erase from cursor to the end of the window: all lines below the
     cursor are deleted, and then the equivalent of *note clrtoeol():
     31c2. is performed.

 -- Method: window.clrtoeol ()

     Erase from cursor to the end of the line.

 -- Method: window.cursyncup ()

     Update the current cursor position of all the ancestors of the
     window to reflect the current cursor position of the window.

 -- Method: window.delch ([y, x])

     Delete any character at ‘(y, x)’.

 -- Method: window.deleteln ()

     Delete the line under the cursor.  All following lines are moved up
     by one line.

 -- Method: window.derwin (begin_y, begin_x)

 -- Method: window.derwin (nlines, ncols, begin_y, begin_x)

     An abbreviation for “derive window”, ‘derwin()’ is the same as
     calling *note subwin(): 31c7, except that 'begin_y' and 'begin_x'
     are relative to the origin of the window, rather than relative to
     the entire screen.  Return a window object for the derived window.

 -- Method: window.echochar (ch[, attr])

     Add character 'ch' with attribute 'attr', and immediately call
     *note refresh(): 316c. on the window.

 -- Method: window.enclose (y, x)

     Test whether the given pair of screen-relative character-cell
     coordinates are enclosed by the given window, returning ‘True’ or
     ‘False’.  It is useful for determining what subset of the screen
     windows enclose the location of a mouse event.

     Changed in version 3.10: Previously it returned ‘1’ or ‘0’ instead
     of ‘True’ or ‘False’.

 -- Attribute: window.encoding

     Encoding used to encode method arguments (Unicode strings and
     characters).  The encoding attribute is inherited from the parent
     window when a subwindow is created, for example with *note
     window.subwin(): 31c7.  By default, current locale encoding is used
     (see *note locale.getencoding(): 2dc.).

     Added in version 3.3.

 -- Method: window.erase ()

     Clear the window.

 -- Method: window.getbegyx ()

     Return a tuple ‘(y, x)’ of coordinates of upper-left corner.

 -- Method: window.getbkgd ()

     Return the given window’s current background character/attribute
     pair.

 -- Method: window.getch ([y, x])

     Get a character.  Note that the integer returned does 'not' have to
     be in ASCII range: function keys, keypad keys and so on are
     represented by numbers higher than 255.  In no-delay mode, return
     ‘-1’ if there is no input, otherwise wait until a key is pressed.

 -- Method: window.get_wch ([y, x])

     Get a wide character.  Return a character for most keys, or an
     integer for function keys, keypad keys, and other special keys.  In
     no-delay mode, raise an exception if there is no input.

     Added in version 3.3.

 -- Method: window.getkey ([y, x])

     Get a character, returning a string instead of an integer, as *note
     getch(): 1647. does.  Function keys, keypad keys and other special
     keys return a multibyte string containing the key name.  In
     no-delay mode, raise an exception if there is no input.

 -- Method: window.getmaxyx ()

     Return a tuple ‘(y, x)’ of the height and width of the window.

 -- Method: window.getparyx ()

     Return the beginning coordinates of this window relative to its
     parent window as a tuple ‘(y, x)’.  Return ‘(-1, -1)’ if this
     window has no parent.

 -- Method: window.getstr ()

 -- Method: window.getstr (n)

 -- Method: window.getstr (y, x)

 -- Method: window.getstr (y, x, n)

     Read a bytes object from the user, with primitive line editing
     capacity.

 -- Method: window.getyx ()

     Return a tuple ‘(y, x)’ of current cursor position relative to the
     window’s upper-left corner.

 -- Method: window.hline (ch, n)

 -- Method: window.hline (y, x, ch, n)

     Display a horizontal line starting at ‘(y, x)’ with length 'n'
     consisting of the character 'ch'.

 -- Method: window.idcok (flag)

     If 'flag' is ‘False’, curses no longer considers using the hardware
     insert/delete character feature of the terminal; if 'flag' is
     ‘True’, use of character insertion and deletion is enabled.  When
     curses is first initialized, use of character insert/delete is
     enabled by default.

 -- Method: window.idlok (flag)

     If 'flag' is ‘True’, ‘curses’ will try and use hardware line
     editing facilities.  Otherwise, line insertion/deletion are
     disabled.

 -- Method: window.immedok (flag)

     If 'flag' is ‘True’, any change in the window image automatically
     causes the window to be refreshed; you no longer have to call *note
     refresh(): 316c. yourself.  However, it may degrade performance
     considerably, due to repeated calls to wrefresh.  This option is
     disabled by default.

 -- Method: window.inch ([y, x])

     Return the character at the given position in the window.  The
     bottom 8 bits are the character proper, and upper bits are the
     attributes.

 -- Method: window.insch (ch[, attr])

 -- Method: window.insch (y, x, ch[, attr])

     Paint character 'ch' at ‘(y, x)’ with attributes 'attr', moving the
     line from position 'x' right by one character.

 -- Method: window.insdelln (nlines)

     Insert 'nlines' lines into the specified window above the current
     line.  The 'nlines' bottom lines are lost.  For negative 'nlines',
     delete 'nlines' lines starting with the one under the cursor, and
     move the remaining lines up.  The bottom 'nlines' lines are
     cleared.  The current cursor position remains the same.

 -- Method: window.insertln ()

     Insert a blank line under the cursor.  All following lines are
     moved down by one line.

 -- Method: window.insnstr (str, n[, attr])

 -- Method: window.insnstr (y, x, str, n[, attr])

     Insert a character string (as many characters as will fit on the
     line) before the character under the cursor, up to 'n' characters.
     If 'n' is zero or negative, the entire string is inserted.  All
     characters to the right of the cursor are shifted right, with the
     rightmost characters on the line being lost.  The cursor position
     does not change (after moving to 'y', 'x', if specified).

 -- Method: window.insstr (str[, attr])

 -- Method: window.insstr (y, x, str[, attr])

     Insert a character string (as many characters as will fit on the
     line) before the character under the cursor.  All characters to the
     right of the cursor are shifted right, with the rightmost
     characters on the line being lost.  The cursor position does not
     change (after moving to 'y', 'x', if specified).

 -- Method: window.instr ([n])

 -- Method: window.instr (y, x[, n])

     Return a bytes object of characters, extracted from the window
     starting at the current cursor position, or at 'y', 'x' if
     specified.  Attributes are stripped from the characters.  If 'n' is
     specified, ‘instr()’ returns a string at most 'n' characters long
     (exclusive of the trailing NUL).

 -- Method: window.is_linetouched (line)

     Return ‘True’ if the specified line was modified since the last
     call to *note refresh(): 316c.; otherwise return ‘False’.  Raise a
     *note curses.error: 3158. exception if 'line' is not valid for the
     given window.

 -- Method: window.is_wintouched ()

     Return ‘True’ if the specified window was modified since the last
     call to *note refresh(): 316c.; otherwise return ‘False’.

 -- Method: window.keypad (flag)

     If 'flag' is ‘True’, escape sequences generated by some keys
     (keypad, function keys) will be interpreted by ‘curses’.  If 'flag'
     is ‘False’, escape sequences will be left as is in the input
     stream.

 -- Method: window.leaveok (flag)

     If 'flag' is ‘True’, cursor is left where it is on update, instead
     of being at “cursor position.” This reduces cursor movement where
     possible.  If possible the cursor will be made invisible.

     If 'flag' is ‘False’, cursor will always be at “cursor position”
     after an update.

 -- Method: window.move (new_y, new_x)

     Move cursor to ‘(new_y, new_x)’.

 -- Method: window.mvderwin (y, x)

     Move the window inside its parent window.  The screen-relative
     parameters of the window are not changed.  This routine is used to
     display different parts of the parent window at the same physical
     position on the screen.

 -- Method: window.mvwin (new_y, new_x)

     Move the window so its upper-left corner is at ‘(new_y, new_x)’.

 -- Method: window.nodelay (flag)

     If 'flag' is ‘True’, *note getch(): 1647. will be non-blocking.

 -- Method: window.notimeout (flag)

     If 'flag' is ‘True’, escape sequences will not be timed out.

     If 'flag' is ‘False’, after a few milliseconds, an escape sequence
     will not be interpreted, and will be left in the input stream as
     is.

 -- Method: window.noutrefresh ()

     Mark for refresh but wait.  This function updates the data
     structure representing the desired state of the window, but does
     not force an update of the physical screen.  To accomplish that,
     call *note doupdate(): 3169.

 -- Method: window.overlay (destwin[, sminrow, smincol, dminrow,
          dmincol, dmaxrow, dmaxcol])

     Overlay the window on top of 'destwin'.  The windows need not be
     the same size, only the overlapping region is copied.  This copy is
     non-destructive, which means that the current background character
     does not overwrite the old contents of 'destwin'.

     To get fine-grained control over the copied region, the second form
     of ‘overlay()’ can be used.  'sminrow' and 'smincol' are the
     upper-left coordinates of the source window, and the other
     variables mark a rectangle in the destination window.

 -- Method: window.overwrite (destwin[, sminrow, smincol, dminrow,
          dmincol, dmaxrow, dmaxcol])

     Overwrite the window on top of 'destwin'.  The windows need not be
     the same size, in which case only the overlapping region is copied.
     This copy is destructive, which means that the current background
     character overwrites the old contents of 'destwin'.

     To get fine-grained control over the copied region, the second form
     of ‘overwrite()’ can be used.  'sminrow' and 'smincol' are the
     upper-left coordinates of the source window, the other variables
     mark a rectangle in the destination window.

 -- Method: window.putwin (file)

     Write all data associated with the window into the provided file
     object.  This information can be later retrieved using the *note
     getwin(): 317f. function.

 -- Method: window.redrawln (beg, num)

     Indicate that the 'num' screen lines, starting at line 'beg', are
     corrupted and should be completely redrawn on the next *note
     refresh(): 316c. call.

 -- Method: window.redrawwin ()

     Touch the entire window, causing it to be completely redrawn on the
     next *note refresh(): 316c. call.

 -- Method: window.refresh ([pminrow, pmincol, sminrow, smincol,
          smaxrow, smaxcol])

     Update the display immediately (sync actual screen with previous
     drawing/deleting methods).

     The 6 optional arguments can only be specified when the window is a
     pad created with *note newpad(): 3191.  The additional parameters
     are needed to indicate what part of the pad and screen are
     involved.  'pminrow' and 'pmincol' specify the upper left-hand
     corner of the rectangle to be displayed in the pad.  'sminrow',
     'smincol', 'smaxrow', and 'smaxcol' specify the edges of the
     rectangle to be displayed on the screen.  The lower right-hand
     corner of the rectangle to be displayed in the pad is calculated
     from the screen coordinates, since the rectangles must be the same
     size.  Both rectangles must be entirely contained within their
     respective structures.  Negative values of 'pminrow', 'pmincol',
     'sminrow', or 'smincol' are treated as if they were zero.

 -- Method: window.resize (nlines, ncols)

     Reallocate storage for a curses window to adjust its dimensions to
     the specified values.  If either dimension is larger than the
     current values, the window’s data is filled with blanks that have
     the current background rendition (as set by *note bkgdset(): 31b3.)
     merged into them.

 -- Method: window.scroll ([lines=1])

     Scroll the screen or scrolling region upward by 'lines' lines.

 -- Method: window.scrollok (flag)

     Control what happens when the cursor of a window is moved off the
     edge of the window or scrolling region, either as a result of a
     newline action on the bottom line, or typing the last character of
     the last line.  If 'flag' is ‘False’, the cursor is left on the
     bottom line.  If 'flag' is ‘True’, the window is scrolled up one
     line.  Note that in order to get the physical scrolling effect on
     the terminal, it is also necessary to call *note idlok(): 31d2.

 -- Method: window.setscrreg (top, bottom)

     Set the scrolling region from line 'top' to line 'bottom'.  All
     scrolling actions will take place in this region.

 -- Method: window.standend ()

     Turn off the standout attribute.  On some terminals this has the
     side effect of turning off all attributes.

 -- Method: window.standout ()

     Turn on attribute 'A_STANDOUT'.

 -- Method: window.subpad (begin_y, begin_x)

 -- Method: window.subpad (nlines, ncols, begin_y, begin_x)

     Return a sub-window, whose upper-left corner is at ‘(begin_y,
     begin_x)’, and whose width/height is 'ncols'/'nlines'.

 -- Method: window.subwin (begin_y, begin_x)

 -- Method: window.subwin (nlines, ncols, begin_y, begin_x)

     Return a sub-window, whose upper-left corner is at ‘(begin_y,
     begin_x)’, and whose width/height is 'ncols'/'nlines'.

     By default, the sub-window will extend from the specified position
     to the lower right corner of the window.

 -- Method: window.syncdown ()

     Touch each location in the window that has been touched in any of
     its ancestor windows.  This routine is called by *note refresh():
     316c, so it should almost never be necessary to call it manually.

 -- Method: window.syncok (flag)

     If 'flag' is ‘True’, then *note syncup(): 31f0. is called
     automatically whenever there is a change in the window.

 -- Method: window.syncup ()

     Touch all locations in ancestors of the window that have been
     changed in the window.

 -- Method: window.timeout (delay)

     Set blocking or non-blocking read behavior for the window.  If
     'delay' is negative, blocking read is used (which will wait
     indefinitely for input).  If 'delay' is zero, then non-blocking
     read is used, and *note getch(): 1647. will return ‘-1’ if no input
     is waiting.  If 'delay' is positive, then ‘getch()’ will block for
     'delay' milliseconds, and return ‘-1’ if there is still no input at
     the end of that time.

 -- Method: window.touchline (start, count[, changed])

     Pretend 'count' lines have been changed, starting with line
     'start'.  If 'changed' is supplied, it specifies whether the
     affected lines are marked as having been changed ('changed'‘=True’)
     or unchanged ('changed'‘=False’).

 -- Method: window.touchwin ()

     Pretend the whole window has been changed, for purposes of drawing
     optimizations.

 -- Method: window.untouchwin ()

     Mark all lines in the window as unchanged since the last call to
     *note refresh(): 316c.

 -- Method: window.vline (ch, n[, attr])

 -- Method: window.vline (y, x, ch, n[, attr])

     Display a vertical line starting at ‘(y, x)’ with length 'n'
     consisting of the character 'ch' with attributes 'attr'.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue35924


File: python.info,  Node: Constants<6>,  Prev: Window Objects,  Up: curses — Terminal handling for character-cell displays

5.17.5.3 Constants
..................

The ‘curses’ module defines the following data members:

 -- Data: curses.ERR

     Some curses routines that return an integer, such as *note getch():
     1647, return *note ERR: 31f5. upon failure.

 -- Data: curses.OK

     Some curses routines that return an integer, such as *note napms():
     16a6, return *note OK: 31f6. upon success.

 -- Data: curses.version

     A bytes object representing the current version of the module.

 -- Data: curses.ncurses_version

     A named tuple containing the three components of the ncurses
     library version: 'major', 'minor', and 'patch'.  All values are
     integers.  The components can also be accessed by name, so
     ‘curses.ncurses_version[0]’ is equivalent to
     ‘curses.ncurses_version.major’ and so on.

     Availability: if the ncurses library is used.

     Added in version 3.8.

 -- Data: curses.COLORS

     The maximum number of colors the terminal can support.  It is
     defined only after the call to *note start_color(): 319e.

 -- Data: curses.COLOR_PAIRS

     The maximum number of color pairs the terminal can support.  It is
     defined only after the call to *note start_color(): 319e.

 -- Data: curses.COLS

     The width of the screen, i.e., the number of columns.  It is
     defined only after the call to *note initscr(): 16a7.  Updated by
     *note update_lines_cols(): e1c, *note resizeterm(): 16ae. and *note
     resize_term(): 16af.

 -- Data: curses.LINES

     The height of the screen, i.e., the number of lines.  It is defined
     only after the call to *note initscr(): 16a7.  Updated by *note
     update_lines_cols(): e1c, *note resizeterm(): 16ae. and *note
     resize_term(): 16af.

Some constants are available to specify character cell attributes.  The
exact constants available are system dependent.

Attribute                    Meaning
                             
-----------------------------------------------------------------
                             
 -- Data:                    Alternate character set mode
          curses.A_ALTCHARSET

 -- Data: curses.A_BLINK     Blink mode
                             
                             
 -- Data: curses.A_BOLD      Bold mode
                             
                             
 -- Data: curses.A_DIM       Dim mode
                             
                             
 -- Data: curses.A_INVIS     Invisible or blank mode
                             
                             
 -- Data: curses.A_ITALIC    Italic mode
                             
                             
 -- Data: curses.A_NORMAL    Normal attribute
                             
                             
 -- Data: curses.A_PROTECT   Protected mode
                             
                             
 -- Data: curses.A_REVERSE   Reverse background and foreground
                             colors
                             
                             
 -- Data:                    Standout mode
          curses.A_STANDOUT  

 -- Data:                    Underline mode
          curses.A_UNDERLINE 

 -- Data:                    Horizontal highlight
          curses.A_HORIZONTAL

 -- Data: curses.A_LEFT      Left highlight
                             
                             
 -- Data: curses.A_LOW       Low highlight
                             
                             
 -- Data: curses.A_RIGHT     Right highlight
                             
                             
 -- Data: curses.A_TOP       Top highlight
                             
                             
 -- Data:                    Vertical highlight
          curses.A_VERTICAL  

Added in version 3.7: ‘A_ITALIC’ was added.

Several constants are available to extract corresponding attributes
returned by some methods.

Bit-mask                      Meaning
                              
------------------------------------------------------------------
                              
 -- Data:                     Bit-mask to extract attributes
          curses.A_ATTRIBUTES 

 -- Data: curses.A_CHARTEXT   Bit-mask to extract a character
                              
                              
 -- Data: curses.A_COLOR      Bit-mask to extract color-pair
                              field information
                              

Keys are referred to by integer constants with names starting with
‘KEY_’.  The exact keycaps available are system dependent.

Key constant                  Key
                              
-------------------------------------------------------------------------------
                              
 -- Data: curses.KEY_MIN      Minimum key value
                              
                              
 -- Data: curses.KEY_BREAK    Break key (unreliable)
                              
                              
 -- Data: curses.KEY_DOWN     Down-arrow
                              
                              
 -- Data: curses.KEY_UP       Up-arrow
                              
                              
 -- Data: curses.KEY_LEFT     Left-arrow
                              
                              
 -- Data: curses.KEY_RIGHT    Right-arrow
                              
                              
 -- Data: curses.KEY_HOME     Home key (upward+left arrow)
                              
                              
 -- Data:                     Backspace (unreliable)
          curses.KEY_BACKSPACE

 -- Data: curses.KEY_F0       Function keys.  Up to 64 function keys are
                              supported.
                              
                              
 -- Data: curses.KEY_Fn       Value of function key 'n'
                              
                              
 -- Data: curses.KEY_DL       Delete line
                              
                              
 -- Data: curses.KEY_IL       Insert line
                              
                              
 -- Data: curses.KEY_DC       Delete character
                              
                              
 -- Data: curses.KEY_IC       Insert char or enter insert mode
                              
                              
 -- Data: curses.KEY_EIC      Exit insert char mode
                              
                              
 -- Data: curses.KEY_CLEAR    Clear screen
                              
                              
 -- Data: curses.KEY_EOS      Clear to end of screen
                              
                              
 -- Data: curses.KEY_EOL      Clear to end of line
                              
                              
 -- Data: curses.KEY_SF       Scroll 1 line forward
                              
                              
 -- Data: curses.KEY_SR       Scroll 1 line backward (reverse)
                              
                              
 -- Data: curses.KEY_NPAGE    Next page
                              
                              
 -- Data: curses.KEY_PPAGE    Previous page
                              
                              
 -- Data: curses.KEY_STAB     Set tab
                              
                              
 -- Data: curses.KEY_CTAB     Clear tab
                              
                              
 -- Data: curses.KEY_CATAB    Clear all tabs
                              
                              
 -- Data: curses.KEY_ENTER    Enter or send (unreliable)
                              
                              
 -- Data: curses.KEY_SRESET   Soft (partial) reset (unreliable)
                              
                              
 -- Data: curses.KEY_RESET    Reset or hard reset (unreliable)
                              
                              
 -- Data: curses.KEY_PRINT    Print
                              
                              
 -- Data: curses.KEY_LL       Home down or bottom (lower left)
                              
                              
 -- Data: curses.KEY_A1       Upper left of keypad
                              
                              
 -- Data: curses.KEY_A3       Upper right of keypad
                              
                              
 -- Data: curses.KEY_B2       Center of keypad
                              
                              
 -- Data: curses.KEY_C1       Lower left of keypad
                              
                              
 -- Data: curses.KEY_C3       Lower right of keypad
                              
                              
 -- Data: curses.KEY_BTAB     Back tab
                              
                              
 -- Data: curses.KEY_BEG      Beg (beginning)
                              
                              
 -- Data: curses.KEY_CANCEL   Cancel
                              
                              
 -- Data: curses.KEY_CLOSE    Close
                              
                              
 -- Data:                     Cmd (command)
          curses.KEY_COMMAND  

 -- Data: curses.KEY_COPY     Copy
                              
                              
 -- Data: curses.KEY_CREATE   Create
                              
                              
 -- Data: curses.KEY_END      End
                              
                              
 -- Data: curses.KEY_EXIT     Exit
                              
                              
 -- Data: curses.KEY_FIND     Find
                              
                              
 -- Data: curses.KEY_HELP     Help
                              
                              
 -- Data: curses.KEY_MARK     Mark
                              
                              
 -- Data:                     Message
          curses.KEY_MESSAGE  

 -- Data: curses.KEY_MOVE     Move
                              
                              
 -- Data: curses.KEY_NEXT     Next
                              
                              
 -- Data: curses.KEY_OPEN     Open
                              
                              
 -- Data:                     Options
          curses.KEY_OPTIONS  

 -- Data:                     Prev (previous)
          curses.KEY_PREVIOUS 

 -- Data: curses.KEY_REDO     Redo
                              
                              
 -- Data:                     Ref (reference)
          curses.KEY_REFERENCE

 -- Data:                     Refresh
          curses.KEY_REFRESH  

 -- Data:                     Replace
          curses.KEY_REPLACE  

 -- Data:                     Restart
          curses.KEY_RESTART  

 -- Data: curses.KEY_RESUME   Resume
                              
                              
 -- Data: curses.KEY_SAVE     Save
                              
                              
 -- Data: curses.KEY_SBEG     Shifted Beg (beginning)
                              
                              
 -- Data:                     Shifted Cancel
          curses.KEY_SCANCEL  

 -- Data:                     Shifted Command
          curses.KEY_SCOMMAND 

 -- Data: curses.KEY_SCOPY    Shifted Copy
                              
                              
 -- Data:                     Shifted Create
          curses.KEY_SCREATE  

 -- Data: curses.KEY_SDC      Shifted Delete char
                              
                              
 -- Data: curses.KEY_SDL      Shifted Delete line
                              
                              
 -- Data: curses.KEY_SELECT   Select
                              
                              
 -- Data: curses.KEY_SEND     Shifted End
                              
                              
 -- Data: curses.KEY_SEOL     Shifted Clear line
                              
                              
 -- Data: curses.KEY_SEXIT    Shifted Exit
                              
                              
 -- Data: curses.KEY_SFIND    Shifted Find
                              
                              
 -- Data: curses.KEY_SHELP    Shifted Help
                              
                              
 -- Data: curses.KEY_SHOME    Shifted Home
                              
                              
 -- Data: curses.KEY_SIC      Shifted Input
                              
                              
 -- Data: curses.KEY_SLEFT    Shifted Left arrow
                              
                              
 -- Data:                     Shifted Message
          curses.KEY_SMESSAGE 

 -- Data: curses.KEY_SMOVE    Shifted Move
                              
                              
 -- Data: curses.KEY_SNEXT    Shifted Next
                              
                              
 -- Data:                     Shifted Options
          curses.KEY_SOPTIONS 

 -- Data:                     Shifted Prev
          curses.KEY_SPREVIOUS

 -- Data: curses.KEY_SPRINT   Shifted Print
                              
                              
 -- Data: curses.KEY_SREDO    Shifted Redo
                              
                              
 -- Data:                     Shifted Replace
          curses.KEY_SREPLACE 

 -- Data: curses.KEY_SRIGHT   Shifted Right arrow
                              
                              
 -- Data: curses.KEY_SRSUME   Shifted Resume
                              
                              
 -- Data: curses.KEY_SSAVE    Shifted Save
                              
                              
 -- Data:                     Shifted Suspend
          curses.KEY_SSUSPEND 

 -- Data: curses.KEY_SUNDO    Shifted Undo
                              
                              
 -- Data:                     Suspend
          curses.KEY_SUSPEND  

 -- Data: curses.KEY_UNDO     Undo
                              
                              
 -- Data: curses.KEY_MOUSE    Mouse event has occurred
                              
                              
 -- Data: curses.KEY_RESIZE   Terminal resize event
                              
                              
 -- Data: curses.KEY_MAX      Maximum key value
                              

On VT100s and their software emulations, such as X terminal emulators,
there are normally at least four function keys (*note KEY_F1: 3212,
‘KEY_F2’, ‘KEY_F3’, ‘KEY_F4’) available, and the arrow keys mapped to
*note KEY_UP: 320c, *note KEY_DOWN: 320b, *note KEY_LEFT: 320d. and
*note KEY_RIGHT: 320e. in the obvious way.  If your machine has a PC
keyboard, it is safe to expect arrow keys and twelve function keys
(older PC keyboards may have only ten function keys); also, the
following keypad mappings are standard:

Keycap                 Constant
                       
---------------------------------------
                       
‘Insert’               KEY_IC
                       
                       
‘Delete’               KEY_DC
                       
                       
‘Home’                 KEY_HOME
                       
                       
‘End’                  KEY_END
                       
                       
‘Page Up’              KEY_PPAGE
                       
                       
‘Page Down’            KEY_NPAGE
                       

The following table lists characters from the alternate character set.
These are inherited from the VT100 terminal, and will generally be
available on software emulations such as X terminals.  When there is no
graphic available, curses falls back on a crude printable ASCII
approximation.

     Note: These are available only after *note initscr(): 16a7. has
     been called.

ACS code                     Meaning
                             
----------------------------------------------------------------------------
                             
 -- Data: curses.ACS_BBSS    alternate name for upper right corner
                             
                             
 -- Data: curses.ACS_BLOCK   solid square block
                             
                             
 -- Data: curses.ACS_BOARD   board of squares
                             
                             
 -- Data: curses.ACS_BSBS    alternate name for horizontal line
                             
                             
 -- Data: curses.ACS_BSSB    alternate name for upper left corner
                             
                             
 -- Data: curses.ACS_BSSS    alternate name for top tee
                             
                             
 -- Data: curses.ACS_BTEE    bottom tee
                             
                             
 -- Data:                    bullet
          curses.ACS_BULLET  

 -- Data:                    checker board (stipple)
          curses.ACS_CKBOARD 

 -- Data:                    arrow pointing down
          curses.ACS_DARROW  

 -- Data:                    degree symbol
          curses.ACS_DEGREE  

 -- Data:                    diamond
          curses.ACS_DIAMOND 

 -- Data:                    greater-than-or-equal-to
          curses.ACS_GEQUAL  

 -- Data: curses.ACS_HLINE   horizontal line
                             
                             
 -- Data:                    lantern symbol
          curses.ACS_LANTERN 

 -- Data:                    left arrow
          curses.ACS_LARROW  

 -- Data:                    less-than-or-equal-to
          curses.ACS_LEQUAL  

 -- Data:                    lower left-hand corner
          curses.ACS_LLCORNER

 -- Data:                    lower right-hand corner
          curses.ACS_LRCORNER

 -- Data: curses.ACS_LTEE    left tee
                             
                             
 -- Data:                    not-equal sign
          curses.ACS_NEQUAL  

 -- Data: curses.ACS_PI      letter pi
                             
                             
 -- Data:                    plus-or-minus sign
          curses.ACS_PLMINUS 

 -- Data: curses.ACS_PLUS    big plus sign
                             
                             
 -- Data:                    right arrow
          curses.ACS_RARROW  

 -- Data: curses.ACS_RTEE    right tee
                             
                             
 -- Data: curses.ACS_S1      scan line 1
                             
                             
 -- Data: curses.ACS_S3      scan line 3
                             
                             
 -- Data: curses.ACS_S7      scan line 7
                             
                             
 -- Data: curses.ACS_S9      scan line 9
                             
                             
 -- Data: curses.ACS_SBBS    alternate name for lower right corner
                             
                             
 -- Data: curses.ACS_SBSB    alternate name for vertical line
                             
                             
 -- Data: curses.ACS_SBSS    alternate name for right tee
                             
                             
 -- Data: curses.ACS_SSBB    alternate name for lower left corner
                             
                             
 -- Data: curses.ACS_SSBS    alternate name for bottom tee
                             
                             
 -- Data: curses.ACS_SSSB    alternate name for left tee
                             
                             
 -- Data: curses.ACS_SSSS    alternate name for crossover or big plus
                             
                             
 -- Data:                    pound sterling
          curses.ACS_STERLING

 -- Data: curses.ACS_TTEE    top tee
                             
                             
 -- Data:                    up arrow
          curses.ACS_UARROW  

 -- Data:                    upper left corner
          curses.ACS_ULCORNER

 -- Data:                    upper right corner
          curses.ACS_URCORNER

 -- Data: curses.ACS_VLINE   vertical line
                             

The following table lists mouse button constants used by *note
getmouse(): 3173.:

Mouse button constant                  Meaning
                                       
-----------------------------------------------------------------------------------------
                                       
 -- Data: curses.BUTTONn_PRESSED       Mouse button 'n' pressed
                                       
                                       
 -- Data: curses.BUTTONn_RELEASED      Mouse button 'n' released
                                       
                                       
 -- Data: curses.BUTTONn_CLICKED       Mouse button 'n' clicked
                                       
                                       
 -- Data:                              Mouse button 'n' double clicked
          curses.BUTTONn_DOUBLE_CLICKED

 -- Data:                              Mouse button 'n' triple clicked
          curses.BUTTONn_TRIPLE_CLICKED

 -- Data: curses.BUTTON_SHIFT          Shift was down during button state change
                                       
                                       
 -- Data: curses.BUTTON_CTRL           Control was down during button state change
                                       
                                       
 -- Data: curses.BUTTON_ALT            Control was down during button state change
                                       

Changed in version 3.10: The ‘BUTTON5_*’ constants are now exposed if
they are provided by the underlying curses library.

The following table lists the predefined colors:

Constant                      Color
                              
---------------------------------------------------------------
                              
 -- Data:                     Black
          curses.COLOR_BLACK  

 -- Data: curses.COLOR_BLUE   Blue
                              
                              
 -- Data: curses.COLOR_CYAN   Cyan (light greenish blue)
                              
                              
 -- Data:                     Green
          curses.COLOR_GREEN  

 -- Data:                     Magenta (purplish red)
          curses.COLOR_MAGENTA

 -- Data: curses.COLOR_RED    Red
                              
                              
 -- Data:                     White
          curses.COLOR_WHITE  

 -- Data:                     Yellow
          curses.COLOR_YELLOW 


File: python.info,  Node: curses textpad — Text input widget for curses programs,  Next: curses ascii — Utilities for ASCII characters,  Prev: curses — Terminal handling for character-cell displays,  Up: Command-line interface libraries

5.17.6 ‘curses.textpad’ — Text input widget for curses programs
---------------------------------------------------------------

The ‘curses.textpad’ module provides a *note Textbox: 3295. class that
handles elementary text editing in a curses window, supporting a set of
keybindings resembling those of Emacs (thus, also of Netscape Navigator,
BBedit 6.x, FrameMaker, and many other programs).  The module also
provides a rectangle-drawing function useful for framing text boxes or
for other purposes.

The module ‘curses.textpad’ defines the following function:

 -- Function: curses.textpad.rectangle (win, uly, ulx, lry, lrx)

     Draw a rectangle.  The first argument must be a window object; the
     remaining arguments are coordinates relative to that window.  The
     second and third arguments are the y and x coordinates of the upper
     left hand corner of the rectangle to be drawn; the fourth and fifth
     arguments are the y and x coordinates of the lower right hand
     corner.  The rectangle will be drawn using VT100/IBM PC forms
     characters on terminals that make this possible (including xterm
     and most other software terminal emulators).  Otherwise it will be
     drawn with ASCII dashes, vertical bars, and plus signs.

* Menu:

* Textbox objects::


File: python.info,  Node: Textbox objects,  Up: curses textpad — Text input widget for curses programs

5.17.6.1 Textbox objects
........................

You can instantiate a *note Textbox: 3295. object as follows:

 -- Class: curses.textpad.Textbox (win)

     Return a textbox widget object.  The 'win' argument should be a
     curses *note window: 3188. object in which the textbox is to be
     contained.  The edit cursor of the textbox is initially located at
     the upper left hand corner of the containing window, with
     coordinates ‘(0, 0)’.  The instance’s *note stripspaces: 3299. flag
     is initially on.

     ‘Textbox’ objects have the following methods:

      -- Method: edit ([validator])

          This is the entry point you will normally use.  It accepts
          editing keystrokes until one of the termination keystrokes is
          entered.  If 'validator' is supplied, it must be a function.
          It will be called for each keystroke entered with the
          keystroke as a parameter; command dispatch is done on the
          result.  This method returns the window contents as a string;
          whether blanks in the window are included is affected by the
          *note stripspaces: 3299. attribute.

      -- Method: do_command (ch)

          Process a single command keystroke.  Here are the supported
          special keystrokes:

          Keystroke              Action
                                 
          -----------------------------------------------------------------------
                                 
          ‘Control’-‘A’          Go to left edge of window.
                                 
                                 
          ‘Control’-‘B’          Cursor left, wrapping to previous line if
                                 appropriate.
                                 
                                 
          ‘Control’-‘D’          Delete character under cursor.
                                 
                                 
          ‘Control’-‘E’          Go to right edge (stripspaces off) or end of
                                 line (stripspaces on).
                                 
                                 
          ‘Control’-‘F’          Cursor right, wrapping to next line when
                                 appropriate.
                                 
                                 
          ‘Control’-‘G’          Terminate, returning the window contents.
                                 
                                 
          ‘Control’-‘H’          Delete character backward.
                                 
                                 
          ‘Control’-‘J’          Terminate if the window is 1 line, otherwise
                                 insert newline.
                                 
                                 
          ‘Control’-‘K’          If line is blank, delete it, otherwise clear
                                 to end of line.
                                 
                                 
          ‘Control’-‘L’          Refresh screen.
                                 
                                 
          ‘Control’-‘N’          Cursor down; move down one line.
                                 
                                 
          ‘Control’-‘O’          Insert a blank line at cursor location.
                                 
                                 
          ‘Control’-‘P’          Cursor up; move up one line.
                                 

          Move operations do nothing if the cursor is at an edge where
          the movement is not possible.  The following synonyms are
          supported where possible:

          Constant                             Keystroke
                                               
          ------------------------------------------------------------
                                               
          *note KEY_LEFT: 320d.                ‘Control’-‘B’
                                               
                                               
          *note KEY_RIGHT: 320e.               ‘Control’-‘F’
                                               
                                               
          *note KEY_UP: 320c.                  ‘Control’-‘P’
                                               
                                               
          *note KEY_DOWN: 320b.                ‘Control’-‘N’
                                               
                                               
          *note KEY_BACKSPACE: 3210.           ‘Control’-‘h’
                                               

          All other keystrokes are treated as a command to insert the
          given character and move right (with line wrapping).

      -- Method: gather ()

          Return the window contents as a string; whether blanks in the
          window are included is affected by the *note stripspaces:
          3299. member.

      -- Attribute: stripspaces

          This attribute is a flag which controls the interpretation of
          blanks in the window.  When it is on, trailing blanks on each
          line are ignored; any cursor motion that would land the cursor
          on a trailing blank goes to the end of that line instead, and
          trailing blanks are stripped when the window contents are
          gathered.


File: python.info,  Node: curses ascii — Utilities for ASCII characters,  Next: curses panel — A panel stack extension for curses,  Prev: curses textpad — Text input widget for curses programs,  Up: Command-line interface libraries

5.17.7 ‘curses.ascii’ — Utilities for ASCII characters
------------------------------------------------------

'Source code:' Lib/curses/ascii.py(1)

__________________________________________________________________

The ‘curses.ascii’ module supplies name constants for ASCII characters
and functions to test membership in various ASCII character classes.
The constants supplied are names for control characters as follows:

Name                Meaning
                    
-----------------------------------------------------------------------
                    
 -- Data:
          curses.ascii.NUL

 -- Data:           Start of heading, console interrupt
          curses.ascii.SOH

 -- Data:           Start of text
          curses.ascii.STX

 -- Data:           End of text
          curses.ascii.ETX

 -- Data:           End of transmission
          curses.ascii.EOT

 -- Data:           Enquiry, goes with *note ACK: 32a6. flow control
          curses.ascii.ENQ

 -- Data:           Acknowledgement
          curses.ascii.ACK

 -- Data:           Bell
          curses.ascii.BEL

 -- Data:           Backspace
          curses.ascii.BS

 -- Data:           Tab
          curses.ascii.TAB

 -- Data:           Alias for *note TAB: 32a9.: “Horizontal tab”
          curses.ascii.HT

 -- Data:           Line feed
          curses.ascii.LF

 -- Data:           Alias for *note LF: 32ab.: “New line”
          curses.ascii.NL

 -- Data:           Vertical tab
          curses.ascii.VT

 -- Data:           Form feed
          curses.ascii.FF

 -- Data:           Carriage return
          curses.ascii.CR

 -- Data:           Shift-out, begin alternate character set
          curses.ascii.SO

 -- Data:           Shift-in, resume default character set
          curses.ascii.SI

 -- Data:           Data-link escape
          curses.ascii.DLE

 -- Data:           XON, for flow control
          curses.ascii.DC1

 -- Data:           Device control 2, block-mode flow control
          curses.ascii.DC2

 -- Data:           XOFF, for flow control
          curses.ascii.DC3

 -- Data:           Device control 4
          curses.ascii.DC4

 -- Data:           Negative acknowledgement
          curses.ascii.NAK

 -- Data:           Synchronous idle
          curses.ascii.SYN

 -- Data:           End transmission block
          curses.ascii.ETB

 -- Data:           Cancel
          curses.ascii.CAN

 -- Data:           End of medium
          curses.ascii.EM

 -- Data:           Substitute
          curses.ascii.SUB

 -- Data:           Escape
          curses.ascii.ESC

 -- Data:           File separator
          curses.ascii.FS

 -- Data:           Group separator
          curses.ascii.GS

 -- Data:           Record separator, block-mode terminator
          curses.ascii.RS

 -- Data:           Unit separator
          curses.ascii.US

 -- Data:           Space
          curses.ascii.SP

 -- Data:           Delete
          curses.ascii.DEL

Note that many of these have little practical significance in modern
usage.  The mnemonics derive from teleprinter conventions that predate
digital computers.

The module supplies the following functions, patterned on those in the
standard C library:

 -- Function: curses.ascii.isalnum (c)

     Checks for an ASCII alphanumeric character; it is equivalent to
     ‘isalpha(c) or isdigit(c)’.

 -- Function: curses.ascii.isalpha (c)

     Checks for an ASCII alphabetic character; it is equivalent to
     ‘isupper(c) or islower(c)’.

 -- Function: curses.ascii.isascii (c)

     Checks for a character value that fits in the 7-bit ASCII set.

 -- Function: curses.ascii.isblank (c)

     Checks for an ASCII whitespace character; space or horizontal tab.

 -- Function: curses.ascii.iscntrl (c)

     Checks for an ASCII control character (in the range 0x00 to 0x1f or
     0x7f).

 -- Function: curses.ascii.isdigit (c)

     Checks for an ASCII decimal digit, ‘'0'’ through ‘'9'’.  This is
     equivalent to ‘c in string.digits’.

 -- Function: curses.ascii.isgraph (c)

     Checks for ASCII any printable character except space.

 -- Function: curses.ascii.islower (c)

     Checks for an ASCII lower-case character.

 -- Function: curses.ascii.isprint (c)

     Checks for any ASCII printable character including space.

 -- Function: curses.ascii.ispunct (c)

     Checks for any printable ASCII character which is not a space or an
     alphanumeric character.

 -- Function: curses.ascii.isspace (c)

     Checks for ASCII white-space characters; space, line feed, carriage
     return, form feed, horizontal tab, vertical tab.

 -- Function: curses.ascii.isupper (c)

     Checks for an ASCII uppercase letter.

 -- Function: curses.ascii.isxdigit (c)

     Checks for an ASCII hexadecimal digit.  This is equivalent to ‘c in
     string.hexdigits’.

 -- Function: curses.ascii.isctrl (c)

     Checks for an ASCII control character (ordinal values 0 to 31).

 -- Function: curses.ascii.ismeta (c)

     Checks for a non-ASCII character (ordinal values 0x80 and above).

These functions accept either integers or single-character strings; when
the argument is a string, it is first converted using the built-in
function *note ord(): 209f.

Note that all these functions check ordinal bit values derived from the
character of the string you pass in; they do not actually know anything
about the host machine’s character encoding.

The following two functions take either a single-character string or
integer byte value; they return a value of the same type.

 -- Function: curses.ascii.ascii (c)

     Return the ASCII value corresponding to the low 7 bits of 'c'.

 -- Function: curses.ascii.ctrl (c)

     Return the control character corresponding to the given character
     (the character bit value is bitwise-anded with 0x1f).

 -- Function: curses.ascii.alt (c)

     Return the 8-bit character corresponding to the given ASCII
     character (the character bit value is bitwise-ored with 0x80).

The following function takes either a single-character string or integer
value; it returns a string.

 -- Function: curses.ascii.unctrl (c)

     Return a string representation of the ASCII character 'c'.  If 'c'
     is printable, this string is the character itself.  If the
     character is a control character (0x00–0x1f) the string consists of
     a caret (‘'^'’) followed by the corresponding uppercase letter.  If
     the character is an ASCII delete (0x7f) the string is ‘'^?'’.  If
     the character has its meta bit (0x80) set, the meta bit is
     stripped, the preceding rules applied, and ‘'!'’ prepended to the
     result.

 -- Data: curses.ascii.controlnames

     A 33-element string array that contains the ASCII mnemonics for the
     thirty-two ASCII control characters from 0 (NUL) to 0x1f (US), in
     order, plus the mnemonic ‘SP’ for the space character.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/curses/ascii.py


File: python.info,  Node: curses panel — A panel stack extension for curses,  Next: cmd — Support for line-oriented command interpreters,  Prev: curses ascii — Utilities for ASCII characters,  Up: Command-line interface libraries

5.17.8 ‘curses.panel’ — A panel stack extension for curses
----------------------------------------------------------

__________________________________________________________________

Panels are windows with the added feature of depth, so they can be
stacked on top of each other, and only the visible portions of each
window will be displayed.  Panels can be added, moved up or down in the
stack, and removed.

* Menu:

* Functions: Functions<7>.
* Panel Objects::


File: python.info,  Node: Functions<7>,  Next: Panel Objects,  Up: curses panel — A panel stack extension for curses

5.17.8.1 Functions
..................

The module ‘curses.panel’ defines the following functions:

 -- Function: curses.panel.bottom_panel ()

     Returns the bottom panel in the panel stack.

 -- Function: curses.panel.new_panel (win)

     Returns a panel object, associating it with the given window 'win'.
     Be aware that you need to keep the returned panel object referenced
     explicitly.  If you don’t, the panel object is garbage collected
     and removed from the panel stack.

 -- Function: curses.panel.top_panel ()

     Returns the top panel in the panel stack.

 -- Function: curses.panel.update_panels ()

     Updates the virtual screen after changes in the panel stack.  This
     does not call *note curses.doupdate(): 3169, so you’ll have to do
     this yourself.


File: python.info,  Node: Panel Objects,  Prev: Functions<7>,  Up: curses panel — A panel stack extension for curses

5.17.8.2 Panel Objects
......................

Panel objects, as returned by *note new_panel(): 32de. above, are
windows with a stacking order.  There’s always a window associated with
a panel which determines the content, while the panel methods are
responsible for the window’s depth in the panel stack.

Panel objects have the following methods:

 -- Method: Panel.above ()

     Returns the panel above the current panel.

 -- Method: Panel.below ()

     Returns the panel below the current panel.

 -- Method: Panel.bottom ()

     Push the panel to the bottom of the stack.

 -- Method: Panel.hidden ()

     Returns ‘True’ if the panel is hidden (not visible), ‘False’
     otherwise.

 -- Method: Panel.hide ()

     Hide the panel.  This does not delete the object, it just makes the
     window on screen invisible.

 -- Method: Panel.move (y, x)

     Move the panel to the screen coordinates ‘(y, x)’.

 -- Method: Panel.replace (win)

     Change the window associated with the panel to the window 'win'.

 -- Method: Panel.set_userptr (obj)

     Set the panel’s user pointer to 'obj'.  This is used to associate
     an arbitrary piece of data with the panel, and can be any Python
     object.

 -- Method: Panel.show ()

     Display the panel (which might have been hidden).

 -- Method: Panel.top ()

     Push panel to the top of the stack.

 -- Method: Panel.userptr ()

     Returns the user pointer for the panel.  This might be any Python
     object.

 -- Method: Panel.window ()

     Returns the window object associated with the panel.


File: python.info,  Node: cmd — Support for line-oriented command interpreters,  Prev: curses panel — A panel stack extension for curses,  Up: Command-line interface libraries

5.17.9 ‘cmd’ — Support for line-oriented command interpreters
-------------------------------------------------------------

'Source code:' Lib/cmd.py(1)

__________________________________________________________________

The *note Cmd: 17d5. class provides a simple framework for writing
line-oriented command interpreters.  These are often useful for test
harnesses, administrative tools, and prototypes that will later be
wrapped in a more sophisticated interface.

 -- Class: cmd.Cmd (completekey='tab', stdin=None, stdout=None)

     A ‘Cmd’ instance or subclass instance is a line-oriented
     interpreter framework.  There is no good reason to instantiate
     ‘Cmd’ itself; rather, it’s useful as a superclass of an interpreter
     class you define yourself in order to inherit ‘Cmd’’s methods and
     encapsulate action methods.

     The optional argument 'completekey' is the *note readline: ba. name
     of a completion key; it defaults to ‘Tab’.  If 'completekey' is not
     *note None: 678. and ‘readline’ is available, command completion is
     done automatically.

     The default, ‘'tab'’, is treated specially, so that it refers to
     the ‘Tab’ key on every *note readline.backend: 17c0.  Specifically,
     if ‘readline.backend’ is ‘editline’, ‘Cmd’ will use ‘'^I'’ instead
     of ‘'tab'’.  Note that other values are not treated this way, and
     might only work with a specific backend.

     The optional arguments 'stdin' and 'stdout' specify the input and
     output file objects that the Cmd instance or subclass instance will
     use for input and output.  If not specified, they will default to
     *note sys.stdin: 540. and *note sys.stdout: aec.

     If you want a given 'stdin' to be used, make sure to set the
     instance’s *note use_rawinput: 32f2. attribute to ‘False’,
     otherwise 'stdin' will be ignored.

     Changed in version 3.13: ‘completekey='tab'’ is replaced by ‘'^I'’
     for ‘editline’.

* Menu:

* Cmd Objects::
* Cmd Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/cmd.py


File: python.info,  Node: Cmd Objects,  Next: Cmd Example,  Up: cmd — Support for line-oriented command interpreters

5.17.9.1 Cmd Objects
....................

A *note Cmd: 17d5. instance has the following methods:

 -- Method: Cmd.cmdloop (intro=None)

     Repeatedly issue a prompt, accept input, parse an initial prefix
     off the received input, and dispatch to action methods, passing
     them the remainder of the line as argument.

     The optional argument is a banner or intro string to be issued
     before the first prompt (this overrides the *note intro: 32f6.
     class attribute).

     If the *note readline: ba. module is loaded, input will
     automatically inherit ‘bash’-like history-list editing (e.g.
     ‘Control’-‘P’ scrolls back to the last command, ‘Control’-‘N’
     forward to the next one, ‘Control’-‘F’ moves the cursor to the
     right non-destructively, ‘Control’-‘B’ moves the cursor to the left
     non-destructively, etc.).

     An end-of-file on input is passed back as the string ‘'EOF'’.

     An interpreter instance will recognize a command name ‘foo’ if and
     only if it has a method ‘do_foo()’.  As a special case, a line
     beginning with the character ‘'?'’ is dispatched to the method
     *note do_help(): 17c4.  As another special case, a line beginning
     with the character ‘'!'’ is dispatched to the method ‘do_shell()’
     (if such a method is defined).

     This method will return when the *note postcmd(): 32f7. method
     returns a true value.  The 'stop' argument to ‘postcmd()’ is the
     return value from the command’s corresponding ‘do_*()’ method.

     If completion is enabled, completing commands will be done
     automatically, and completing of commands args is done by calling
     ‘complete_foo()’ with arguments 'text', 'line', 'begidx', and
     'endidx'.  'text' is the string prefix we are attempting to match:
     all returned matches must begin with it.  'line' is the current
     input line with leading whitespace removed, 'begidx' and 'endidx'
     are the beginning and ending indexes of the prefix text, which
     could be used to provide different completion depending upon which
     position the argument is in.

 -- Method: Cmd.do_help (arg)

     All subclasses of *note Cmd: 17d5. inherit a predefined
     ‘do_help()’.  This method, called with an argument ‘'bar'’, invokes
     the corresponding method ‘help_bar()’, and if that is not present,
     prints the docstring of ‘do_bar()’, if available.  With no
     argument, ‘do_help()’ lists all available help topics (that is, all
     commands with corresponding ‘help_*()’ methods or commands that
     have docstrings), and also lists any undocumented commands.

 -- Method: Cmd.onecmd (str)

     Interpret the argument as though it had been typed in response to
     the prompt.  This may be overridden, but should not normally need
     to be; see the *note precmd(): 32f9. and *note postcmd(): 32f7.
     methods for useful execution hooks.  The return value is a flag
     indicating whether interpretation of commands by the interpreter
     should stop.  If there is a ‘do_*()’ method for the command 'str',
     the return value of that method is returned, otherwise the return
     value from the *note default(): 32fa. method is returned.

 -- Method: Cmd.emptyline ()

     Method called when an empty line is entered in response to the
     prompt.  If this method is not overridden, it repeats the last
     nonempty command entered.

 -- Method: Cmd.default (line)

     Method called on an input line when the command prefix is not
     recognized.  If this method is not overridden, it prints an error
     message and returns.

 -- Method: Cmd.completedefault (text, line, begidx, endidx)

     Method called to complete an input line when no command-specific
     ‘complete_*()’ method is available.  By default, it returns an
     empty list.

 -- Method: Cmd.columnize (list, displaywidth=80)

     Method called to display a list of strings as a compact set of
     columns.  Each column is only as wide as necessary.  Columns are
     separated by two spaces for readability.

 -- Method: Cmd.precmd (line)

     Hook method executed just before the command line 'line' is
     interpreted, but after the input prompt is generated and issued.
     This method is a stub in *note Cmd: 17d5.; it exists to be
     overridden by subclasses.  The return value is used as the command
     which will be executed by the *note onecmd(): 32f8. method; the
     ‘precmd()’ implementation may re-write the command or simply return
     'line' unchanged.

 -- Method: Cmd.postcmd (stop, line)

     Hook method executed just after a command dispatch is finished.
     This method is a stub in *note Cmd: 17d5.; it exists to be
     overridden by subclasses.  'line' is the command line which was
     executed, and 'stop' is a flag which indicates whether execution
     will be terminated after the call to ‘postcmd()’; this will be the
     return value of the *note onecmd(): 32f8. method.  The return value
     of this method will be used as the new value for the internal flag
     which corresponds to 'stop'; returning false will cause
     interpretation to continue.

 -- Method: Cmd.preloop ()

     Hook method executed once when *note cmdloop(): 32f5. is called.
     This method is a stub in *note Cmd: 17d5.; it exists to be
     overridden by subclasses.

 -- Method: Cmd.postloop ()

     Hook method executed once when *note cmdloop(): 32f5. is about to
     return.  This method is a stub in *note Cmd: 17d5.; it exists to be
     overridden by subclasses.

Instances of *note Cmd: 17d5. subclasses have some public instance
variables:

 -- Attribute: Cmd.prompt

     The prompt issued to solicit input.

 -- Attribute: Cmd.identchars

     The string of characters accepted for the command prefix.

 -- Attribute: Cmd.lastcmd

     The last nonempty command prefix seen.

 -- Attribute: Cmd.cmdqueue

     A list of queued input lines.  The cmdqueue list is checked in
     *note cmdloop(): 32f5. when new input is needed; if it is nonempty,
     its elements will be processed in order, as if entered at the
     prompt.

 -- Attribute: Cmd.intro

     A string to issue as an intro or banner.  May be overridden by
     giving the *note cmdloop(): 32f5. method an argument.

 -- Attribute: Cmd.doc_header

     The header to issue if the help output has a section for documented
     commands.

 -- Attribute: Cmd.misc_header

     The header to issue if the help output has a section for
     miscellaneous help topics (that is, there are ‘help_*()’ methods
     without corresponding ‘do_*()’ methods).

 -- Attribute: Cmd.undoc_header

     The header to issue if the help output has a section for
     undocumented commands (that is, there are ‘do_*()’ methods without
     corresponding ‘help_*()’ methods).

 -- Attribute: Cmd.ruler

     The character used to draw separator lines under the help-message
     headers.  If empty, no ruler line is drawn.  It defaults to ‘'='’.

 -- Attribute: Cmd.use_rawinput

     A flag, defaulting to true.  If true, *note cmdloop(): 32f5. uses
     *note input(): 1320. to display a prompt and read the next command;
     if false, *note sys.stdout.write(): aec. and *note
     sys.stdin.readline(): 540. are used.  (This means that by importing
     *note readline: ba, on systems that support it, the interpreter
     will automatically support ‘Emacs’-like line editing and
     command-history keystrokes.)


File: python.info,  Node: Cmd Example,  Prev: Cmd Objects,  Up: cmd — Support for line-oriented command interpreters

5.17.9.2 Cmd Example
....................

The ‘cmd’ module is mainly useful for building custom shells that let a
user work with a program interactively.

This section presents a simple example of how to build a shell around a
few of the commands in the *note turtle: 101. module.

Basic turtle commands such as *note forward(): 3309. are added to a
*note Cmd: 17d5. subclass with method named ‘do_forward()’.  The
argument is converted to a number and dispatched to the turtle module.
The docstring is used in the help utility provided by the shell.

The example also includes a basic record and playback facility
implemented with the *note precmd(): 32f9. method which is responsible
for converting the input to lowercase and writing the commands to a
file.  The ‘do_playback()’ method reads the file and adds the recorded
commands to the *note cmdqueue: 3302. for immediate playback:

     import cmd, sys
     from turtle import *

     class TurtleShell(cmd.Cmd):
         intro = 'Welcome to the turtle shell.   Type help or ? to list commands.\n'
         prompt = '(turtle) '
         file = None

         # ----- basic turtle commands -----
         def do_forward(self, arg):
             'Move the turtle forward by the specified distance:  FORWARD 10'
             forward(*parse(arg))
         def do_right(self, arg):
             'Turn turtle right by given number of degrees:  RIGHT 20'
             right(*parse(arg))
         def do_left(self, arg):
             'Turn turtle left by given number of degrees:  LEFT 90'
             left(*parse(arg))
         def do_goto(self, arg):
             'Move turtle to an absolute position with changing orientation.  GOTO 100 200'
             goto(*parse(arg))
         def do_home(self, arg):
             'Return turtle to the home position:  HOME'
             home()
         def do_circle(self, arg):
             'Draw circle with given radius an options extent and steps:  CIRCLE 50'
             circle(*parse(arg))
         def do_position(self, arg):
             'Print the current turtle position:  POSITION'
             print('Current position is %d %d\n' % position())
         def do_heading(self, arg):
             'Print the current turtle heading in degrees:  HEADING'
             print('Current heading is %d\n' % (heading(),))
         def do_color(self, arg):
             'Set the color:  COLOR BLUE'
             color(arg.lower())
         def do_undo(self, arg):
             'Undo (repeatedly) the last turtle action(s):  UNDO'
         def do_reset(self, arg):
             'Clear the screen and return turtle to center:  RESET'
             reset()
         def do_bye(self, arg):
             'Stop recording, close the turtle window, and exit:  BYE'
             print('Thank you for using Turtle')
             self.close()
             bye()
             return True

         # ----- record and playback -----
         def do_record(self, arg):
             'Save future commands to filename:  RECORD rose.cmd'
             self.file = open(arg, 'w')
         def do_playback(self, arg):
             'Playback commands from a file:  PLAYBACK rose.cmd'
             self.close()
             with open(arg) as f:
                 self.cmdqueue.extend(f.read().splitlines())
         def precmd(self, line):
             line = line.lower()
             if self.file and 'playback' not in line:
                 print(line, file=self.file)
             return line
         def close(self):
             if self.file:
                 self.file.close()
                 self.file = None

     def parse(arg):
         'Convert a series of zero or more numbers to an argument tuple'
         return tuple(map(int, arg.split()))

     if __name__ == '__main__':
         TurtleShell().cmdloop()

Here is a sample session with the turtle shell showing the help
functions, using blank lines to repeat commands, and the simple record
and playback facility:

     Welcome to the turtle shell.   Type help or ? to list commands.

     (turtle) ?

     Documented commands (type help <topic>):
     ========================================
     bye     color    goto     home  playback  record  right
     circle  forward  heading  left  position  reset   undo

     (turtle) help forward
     Move the turtle forward by the specified distance:  FORWARD 10
     (turtle) record spiral.cmd
     (turtle) position
     Current position is 0 0

     (turtle) heading
     Current heading is 0

     (turtle) reset
     (turtle) circle 20
     (turtle) right 30
     (turtle) circle 40
     (turtle) right 30
     (turtle) circle 60
     (turtle) right 30
     (turtle) circle 80
     (turtle) right 30
     (turtle) circle 100
     (turtle) right 30
     (turtle) circle 120
     (turtle) right 30
     (turtle) circle 120
     (turtle) heading
     Current heading is 180

     (turtle) forward 100
     (turtle)
     (turtle) right 90
     (turtle) forward 100
     (turtle)
     (turtle) right 90
     (turtle) forward 400
     (turtle) right 90
     (turtle) forward 500
     (turtle) right 90
     (turtle) forward 400
     (turtle) right 90
     (turtle) forward 300
     (turtle) playback spiral.cmd
     Current position is 0 0

     Current heading is 0

     Current heading is 180

     (turtle) bye
     Thank you for using Turtle


File: python.info,  Node: Concurrent Execution,  Next: Networking and Interprocess Communication,  Prev: Command-line interface libraries,  Up: The Python Standard Library

5.18 Concurrent Execution
=========================

The modules described in this chapter provide support for concurrent
execution of code.  The appropriate choice of tool will depend on the
task to be executed (CPU bound vs IO bound) and preferred style of
development (event driven cooperative multitasking vs preemptive
multitasking).  Here’s an overview:

* Menu:

* threading — Thread-based parallelism::
* multiprocessing — Process-based parallelism::
* multiprocessing.shared_memory — Shared memory for direct access across processes: multiprocessing shared_memory — Shared memory for direct access across processes.
* The concurrent package::
* concurrent.futures — Launching parallel tasks: concurrent futures — Launching parallel tasks.
* subprocess — Subprocess management::
* sched — Event scheduler::
* queue — A synchronized queue class::
* contextvars — Context Variables::
* _thread — Low-level threading API::


File: python.info,  Node: threading — Thread-based parallelism,  Next: multiprocessing — Process-based parallelism,  Up: Concurrent Execution

5.18.1 ‘threading’ — Thread-based parallelism
---------------------------------------------

'Source code:' Lib/threading.py(1)

__________________________________________________________________

This module constructs higher-level threading interfaces on top of the
lower level *note _thread: 2. module.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

* Menu:

* Introduction: Introduction<8>.
* GIL and performance considerations::
* Reference: Reference<2>.
* Using locks, conditions, and semaphores in the with statement: Using locks conditions and semaphores in the with statement.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/threading.py


File: python.info,  Node: Introduction<8>,  Next: GIL and performance considerations,  Up: threading — Thread-based parallelism

5.18.1.1 Introduction
.....................

The ‘threading’ module provides a way to run multiple threads(1)
(smaller units of a process) concurrently within a single process.  It
allows for the creation and management of threads, making it possible to
execute tasks in parallel, sharing memory space.  Threads are
particularly useful when tasks are I/O bound, such as file operations or
making network requests, where much of the time is spent waiting for
external resources.

A typical use case for ‘threading’ includes managing a pool of worker
threads that can process multiple tasks concurrently.  Here’s a basic
example of creating and starting threads using *note Thread: 956.:

     import threading
     import time

     def crawl(link, delay=3):
         print(f"crawl started for {link}")
         time.sleep(delay)  # Blocking I/O (simulating a network request)
         print(f"crawl ended for {link}")

     links = [
         "https://python.org",
         "https://docs.python.org",
         "https://peps.python.org",
     ]

     # Start threads for each link
     threads = []
     for link in links:
         # Using `args` to pass positional arguments and `kwargs` for keyword arguments
         t = threading.Thread(target=crawl, args=(link,), kwargs={"delay": 2})
         threads.append(t)

     # Start each thread
     for t in threads:
         t.start()

     # Wait for all threads to finish
     for t in threads:
         t.join()

Changed in version 3.7: This module used to be optional, it is now
always available.

See also
........

*note concurrent.futures.ThreadPoolExecutor: 745. offers a higher level
interface to push tasks to a background thread without blocking
execution of the calling thread, while still being able to retrieve
their results when needed.

*note queue: b6. provides a thread-safe interface for exchanging data
between running threads.

*note asyncio: a. offers an alternative approach to achieving task level
concurrency without requiring the use of multiple operating system
threads.

     Note: In the Python 2.x series, this module contained ‘camelCase’
     names for some methods and functions.  These are deprecated as of
     Python 3.10, but they are still supported for compatibility with
     Python 2.5 and lower.

'CPython implementation detail:' In CPython, due to the *note Global
Interpreter Lock: 148, only one thread can execute Python code at once
(even though certain performance-oriented libraries might overcome this
limitation).  If you want your application to make better use of the
computational resources of multi-core machines, you are advised to use
*note multiprocessing: 94. or *note
concurrent.futures.ProcessPoolExecutor: 8f7.  However, threading is
still an appropriate model if you want to run multiple I/O-bound tasks
simultaneously.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Thread_(computing)


File: python.info,  Node: GIL and performance considerations,  Next: Reference<2>,  Prev: Introduction<8>,  Up: threading — Thread-based parallelism

5.18.1.2 GIL and performance considerations
...........................................

Unlike the *note multiprocessing: 94. module, which uses separate
processes to bypass the *note global interpreter lock: 148. (GIL), the
threading module operates within a single process, meaning that all
threads share the same memory space.  However, the GIL limits the
performance gains of threading when it comes to CPU-bound tasks, as only
one thread can execute Python bytecode at a time.  Despite this, threads
remain a useful tool for achieving concurrency in many scenarios.

As of Python 3.13, experimental *note free-threaded: 15b3. builds can
disable the GIL, enabling true parallel execution of threads, but this
feature is not available by default (see PEP 703(1)).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/


File: python.info,  Node: Reference<2>,  Next: Using locks conditions and semaphores in the with statement,  Prev: GIL and performance considerations,  Up: threading — Thread-based parallelism

5.18.1.3 Reference
..................

This module defines the following functions:

 -- Function: threading.active_count ()

     Return the number of *note Thread: 956. objects currently alive.
     The returned count is equal to the length of the list returned by
     *note enumerate(): 1a00.

     The function ‘activeCount’ is a deprecated alias for this function.

 -- Function: threading.current_thread ()

     Return the current *note Thread: 956. object, corresponding to the
     caller’s thread of control.  If the caller’s thread of control was
     not created through the ‘threading’ module, a dummy thread object
     with limited functionality is returned.

     The function ‘currentThread’ is a deprecated alias for this
     function.

 -- Function: threading.excepthook (args, /)

     Handle uncaught exception raised by *note Thread.run(): a4a.

     The 'args' argument has the following attributes:

        * 'exc_type': Exception type.

        * 'exc_value': Exception value, can be ‘None’.

        * 'exc_traceback': Exception traceback, can be ‘None’.

        * 'thread': Thread which raised the exception, can be ‘None’.

     If 'exc_type' is *note SystemExit: d69, the exception is silently
     ignored.  Otherwise, the exception is printed out on *note
     sys.stderr: 943.

     If this function raises an exception, *note sys.excepthook(): 811.
     is called to handle it.

     *note threading.excepthook(): 851. can be overridden to control how
     uncaught exceptions raised by *note Thread.run(): a4a. are handled.

     Storing 'exc_value' using a custom hook can create a reference
     cycle.  It should be cleared explicitly to break the reference
     cycle when the exception is no longer needed.

     Storing 'thread' using a custom hook can resurrect it if it is set
     to an object which is being finalized.  Avoid storing 'thread'
     after the custom hook completes to avoid resurrecting objects.

     See also
     ........

     *note sys.excepthook(): 811. handles uncaught exceptions.

     Added in version 3.8.

 -- Data: threading.__excepthook__

     Holds the original value of *note threading.excepthook(): 851.  It
     is saved so that the original value can be restored in case they
     happen to get replaced with broken or alternative objects.

     Added in version 3.10.

 -- Function: threading.get_ident ()

     Return the ‘thread identifier’ of the current thread.  This is a
     nonzero integer.  Its value has no direct meaning; it is intended
     as a magic cookie to be used e.g.  to index a dictionary of
     thread-specific data.  Thread identifiers may be recycled when a
     thread exits and another thread is created.

     Added in version 3.3.

 -- Function: threading.get_native_id ()

     Return the native integral Thread ID of the current thread assigned
     by the kernel.  This is a non-negative integer.  Its value may be
     used to uniquely identify this particular thread system-wide (until
     the thread terminates, after which the value may be recycled by the
     OS).

     *note Availability: 1ef7.: Windows, FreeBSD, Linux, macOS, OpenBSD,
     NetBSD, AIX, DragonFlyBSD, GNU/kFreeBSD.

     Added in version 3.8.

     Changed in version 3.13: Added support for GNU/kFreeBSD.

 -- Function: threading.enumerate ()

     Return a list of all *note Thread: 956. objects currently active.
     The list includes daemonic threads and dummy thread objects created
     by *note current_thread(): 309.  It excludes terminated threads and
     threads that have not yet been started.  However, the main thread
     is always part of the result, even when terminated.

 -- Function: threading.main_thread ()

     Return the main *note Thread: 956. object.  In normal conditions,
     the main thread is the thread from which the Python interpreter was
     started.

     Added in version 3.4.

 -- Function: threading.settrace (func)

     Set a trace function for all threads started from the ‘threading’
     module.  The 'func' will be passed to *note sys.settrace(): 154e.
     for each thread, before its *note run(): a4a. method is called.

 -- Function: threading.settrace_all_threads (func)

     Set a trace function for all threads started from the ‘threading’
     module and all Python threads that are currently executing.

     The 'func' will be passed to *note sys.settrace(): 154e. for each
     thread, before its *note run(): a4a. method is called.

     Added in version 3.12.

 -- Function: threading.gettrace ()

     Get the trace function as set by *note settrace(): 84e.

     Added in version 3.10.

 -- Function: threading.setprofile (func)

     Set a profile function for all threads started from the ‘threading’
     module.  The 'func' will be passed to *note sys.setprofile(): 154d.
     for each thread, before its *note run(): a4a. method is called.

 -- Function: threading.setprofile_all_threads (func)

     Set a profile function for all threads started from the ‘threading’
     module and all Python threads that are currently executing.

     The 'func' will be passed to *note sys.setprofile(): 154d. for each
     thread, before its *note run(): a4a. method is called.

     Added in version 3.12.

 -- Function: threading.getprofile ()

     Get the profiler function as set by *note setprofile(): 84f.

     Added in version 3.10.

 -- Function: threading.stack_size ([size])

     Return the thread stack size used when creating new threads.  The
     optional 'size' argument specifies the stack size to be used for
     subsequently created threads, and must be 0 (use platform or
     configured default) or a positive integer value of at least 32,768
     (32 KiB). If 'size' is not specified, 0 is used.  If changing the
     thread stack size is unsupported, a *note RuntimeError: 195. is
     raised.  If the specified stack size is invalid, a *note
     ValueError: 202. is raised and the stack size is unmodified.  32
     KiB is currently the minimum supported stack size value to
     guarantee sufficient stack space for the interpreter itself.  Note
     that some platforms may have particular restrictions on values for
     the stack size, such as requiring a minimum stack size > 32 KiB or
     requiring allocation in multiples of the system memory page size -
     platform documentation should be referred to for more information
     (4 KiB pages are common; using multiples of 4096 for the stack size
     is the suggested approach in the absence of more specific
     information).

     *note Availability: 1ef7.: Windows, pthreads.

     Unix platforms with POSIX threads support.

This module also defines the following constant:

 -- Data: threading.TIMEOUT_MAX

     The maximum value allowed for the 'timeout' parameter of blocking
     functions (*note Lock.acquire(): 69b, *note RLock.acquire(): eaf,
     *note Condition.wait(): 1a0c, etc.).  Specifying a timeout greater
     than this value will raise an *note OverflowError: 888.

     Added in version 3.2.

This module defines a number of classes, which are detailed in the
sections below.

The design of this module is loosely based on Java’s threading model.
However, where Java makes locks and condition variables basic behavior
of every object, they are separate objects in Python.  Python’s *note
Thread: 956. class supports a subset of the behavior of Java’s Thread
class; currently, there are no priorities, no thread groups, and threads
cannot be destroyed, stopped, suspended, resumed, or interrupted.  The
static methods of Java’s Thread class, when implemented, are mapped to
module-level functions.

All of the methods described below are executed atomically.

* Menu:

* Thread-local data::
* Thread objects::
* Lock objects::
* RLock objects::
* Condition objects::
* Semaphore objects::
* Semaphore example::
* Event objects::
* Timer objects::
* Barrier objects::


File: python.info,  Node: Thread-local data,  Next: Thread objects,  Up: Reference<2>

5.18.1.4 Thread-local data
..........................

Thread-local data is data whose values are thread specific.  If you have
data that you want to be local to a thread, create a *note local: 1650.
object and use its attributes:

     >>> mydata = local()
     >>> mydata.number = 42
     >>> mydata.number
     42

You can also access the *note local: 1650.-object’s dictionary:

     >>> mydata.__dict__
     {'number': 42}
     >>> mydata.__dict__.setdefault('widgets', [])
     []
     >>> mydata.widgets
     []

If we access the data in a different thread:

     >>> log = []
     >>> def f():
     ...     items = sorted(mydata.__dict__.items())
     ...     log.append(items)
     ...     mydata.number = 11
     ...     log.append(mydata.number)

     >>> import threading
     >>> thread = threading.Thread(target=f)
     >>> thread.start()
     >>> thread.join()
     >>> log
     [[], 11]

we get different data.  Furthermore, changes made in the other thread
don’t affect data seen in this thread:

     >>> mydata.number
     42

Of course, values you get from a *note local: 1650. object, including
their *note __dict__: 55e. attribute, are for whatever thread was
current at the time the attribute was read.  For that reason, you
generally don’t want to save these values across threads, as they apply
only to the thread they came from.

You can create custom *note local: 1650. objects by subclassing the
‘local’ class:

     >>> class MyLocal(local):
     ...     number = 2
     ...     def __init__(self, /, **kw):
     ...         self.__dict__.update(kw)
     ...     def squared(self):
     ...         return self.number ** 2

This can be useful to support default values, methods and
initialization.  Note that if you define an *note __init__(): 6b3.
method, it will be called each time the *note local: 1650. object is
used in a separate thread.  This is necessary to initialize each
thread’s dictionary.

Now if we create a *note local: 1650. object:

     >>> mydata = MyLocal(color='red')

we have a default number:

     >>> mydata.number
     2

an initial color:

     >>> mydata.color
     'red'
     >>> del mydata.color

And a method that operates on the data:

     >>> mydata.squared()
     4

As before, we can access the data in a separate thread:

     >>> log = []
     >>> thread = threading.Thread(target=f)
     >>> thread.start()
     >>> thread.join()
     >>> log
     [[('color', 'red')], 11]

without affecting this thread’s data:

     >>> mydata.number
     2
     >>> mydata.color
     Traceback (most recent call last):
     ...
     AttributeError: 'MyLocal' object has no attribute 'color'

Note that subclasses can define *note __slots__: 5e2, but they are not
thread local.  They are shared across threads:

     >>> class MyLocal(local):
     ...     __slots__ = 'number'

     >>> mydata = MyLocal()
     >>> mydata.number = 42
     >>> mydata.color = 'red'

So, the separate thread:

     >>> thread = threading.Thread(target=f)
     >>> thread.start()
     >>> thread.join()

affects what we see:

     >>> mydata.number
     11

 -- Class: threading.local

     A class that represents thread-local data.


File: python.info,  Node: Thread objects,  Next: Lock objects,  Prev: Thread-local data,  Up: Reference<2>

5.18.1.5 Thread objects
.......................

The *note Thread: 956. class represents an activity that is run in a
separate thread of control.  There are two ways to specify the activity:
by passing a callable object to the constructor, or by overriding the
*note run(): a4a. method in a subclass.  No other methods (except for
the constructor) should be overridden in a subclass.  In other words,
'only' override the ‘__init__()’ and ‘run()’ methods of this class.

Once a thread object is created, its activity must be started by calling
the thread’s *note start(): 2ea8. method.  This invokes the *note run():
a4a. method in a separate thread of control.

Once the thread’s activity is started, the thread is considered ‘alive’.
It stops being alive when its *note run(): a4a. method terminates –
either normally, or by raising an unhandled exception.  The *note
is_alive(): 957. method tests whether the thread is alive.

Other threads can call a thread’s *note join(): 1229. method.  This
blocks the calling thread until the thread whose ‘join()’ method is
called is terminated.

A thread has a name.  The name can be passed to the constructor, and
read or changed through the *note name: 308. attribute.

If the *note run(): a4a. method raises an exception, *note
threading.excepthook(): 851. is called to handle it.  By default,
‘threading.excepthook()’ ignores silently *note SystemExit: d69.

A thread can be flagged as a “daemon thread”.  The significance of this
flag is that the entire Python program exits when only daemon threads
are left.  The initial value is inherited from the creating thread.  The
flag can be set through the *note daemon: 306. property or the 'daemon'
constructor argument.

     Note: Daemon threads are abruptly stopped at shutdown.  Their
     resources (such as open files, database transactions, etc.)  may
     not be released properly.  If you want your threads to stop
     gracefully, make them non-daemonic and use a suitable signalling
     mechanism such as an *note Event: 119c.

There is a “main thread” object; this corresponds to the initial thread
of control in the Python program.  It is not a daemon thread.

There is the possibility that “dummy thread objects” are created.  These
are thread objects corresponding to “alien threads”, which are threads
of control started outside the threading module, such as directly from C
code.  Dummy thread objects have limited functionality; they are always
considered alive and daemonic, and cannot be *note joined: 3318.  They
are never deleted, since it is impossible to detect the termination of
alien threads.

 -- Class: threading.Thread (group=None, target=None, name=None,
          args=(), kwargs={}, *, daemon=None)

     This constructor should always be called with keyword arguments.
     Arguments are:

     'group' should be ‘None’; reserved for future extension when a
     ‘ThreadGroup’ class is implemented.

     'target' is the callable object to be invoked by the *note run():
     a4a. method.  Defaults to ‘None’, meaning nothing is called.

     'name' is the thread name.  By default, a unique name is
     constructed of the form “Thread-'N'” where 'N' is a small decimal
     number, or “Thread-'N' (target)” where “target” is
     ‘target.__name__’ if the 'target' argument is specified.

     'args' is a list or tuple of arguments for the target invocation.
     Defaults to ‘()’.

     'kwargs' is a dictionary of keyword arguments for the target
     invocation.  Defaults to ‘{}’.

     If not ‘None’, 'daemon' explicitly sets whether the thread is
     daemonic.  If ‘None’ (the default), the daemonic property is
     inherited from the current thread.

     If the subclass overrides the constructor, it must make sure to
     invoke the base class constructor (‘Thread.__init__()’) before
     doing anything else to the thread.

     Changed in version 3.3: Added the 'daemon' parameter.

     Changed in version 3.10: Use the 'target' name if 'name' argument
     is omitted.

      -- Method: start ()

          Start the thread’s activity.

          It must be called at most once per thread object.  It arranges
          for the object’s *note run(): a4a. method to be invoked in a
          separate thread of control.

          This method will raise a *note RuntimeError: 195. if called
          more than once on the same thread object.

      -- Method: run ()

          Method representing the thread’s activity.

          You may override this method in a subclass.  The standard
          ‘run()’ method invokes the callable object passed to the
          object’s constructor as the 'target' argument, if any, with
          positional and keyword arguments taken from the 'args' and
          'kwargs' arguments, respectively.

          Using list or tuple as the 'args' argument which passed to the
          ‘Thread’ could achieve the same effect.

          Example:

               >>> from threading import Thread
               >>> t = Thread(target=print, args=[1])
               >>> t.run()
               1
               >>> t = Thread(target=print, args=(1,))
               >>> t.run()
               1

      -- Method: join (timeout=None)

          Wait until the thread terminates.  This blocks the calling
          thread until the thread whose ‘join()’ method is called
          terminates – either normally or through an unhandled exception
          – or until the optional timeout occurs.

          When the 'timeout' argument is present and not ‘None’, it
          should be a floating-point number specifying a timeout for the
          operation in seconds (or fractions thereof).  As ‘join()’
          always returns ‘None’, you must call *note is_alive(): 957.
          after ‘join()’ to decide whether a timeout happened – if the
          thread is still alive, the ‘join()’ call timed out.

          When the 'timeout' argument is not present or ‘None’, the
          operation will block until the thread terminates.

          A thread can be joined many times.

          ‘join()’ raises a *note RuntimeError: 195. if an attempt is
          made to join the current thread as that would cause a
          deadlock.  It is also an error to ‘join()’ a thread before it
          has been started and attempts to do so raise the same
          exception.

      -- Attribute: name

          A string used for identification purposes only.  It has no
          semantics.  Multiple threads may be given the same name.  The
          initial name is set by the constructor.

      -- Method: getName ()
      -- Method: setName ()

          Deprecated getter/setter API for *note name: 308.; use it
          directly as a property instead.

          Deprecated since version 3.10.

      -- Attribute: ident

          The ‘thread identifier’ of this thread or ‘None’ if the thread
          has not been started.  This is a nonzero integer.  See the
          *note get_ident(): 119e. function.  Thread identifiers may be
          recycled when a thread exits and another thread is created.
          The identifier is available even after the thread has exited.

      -- Attribute: native_id

          The Thread ID (‘TID’) of this thread, as assigned by the OS
          (kernel).  This is a non-negative integer, or ‘None’ if the
          thread has not been started.  See the *note get_native_id():
          a4b. function.  This value may be used to uniquely identify
          this particular thread system-wide (until the thread
          terminates, after which the value may be recycled by the OS).

               Note: Similar to Process IDs, Thread IDs are only valid
               (guaranteed unique system-wide) from the time the thread
               is created until the thread has been terminated.

          *note Availability: 1ef7.: Windows, FreeBSD, Linux, macOS,
          OpenBSD, NetBSD, AIX, DragonFlyBSD.

          Added in version 3.8.

      -- Method: is_alive ()

          Return whether the thread is alive.

          This method returns ‘True’ just before the *note run(): a4a.
          method starts until just after the ‘run()’ method terminates.
          The module function *note enumerate(): 1a00. returns a list of
          all alive threads.

      -- Attribute: daemon

          A boolean value indicating whether this thread is a daemon
          thread (‘True’) or not (‘False’).  This must be set before
          *note start(): 2ea8. is called, otherwise *note RuntimeError:
          195. is raised.  Its initial value is inherited from the
          creating thread; the main thread is not a daemon thread and
          therefore all threads created in the main thread default to
          ‘daemon’ = ‘False’.

          The entire Python program exits when no alive non-daemon
          threads are left.

      -- Method: isDaemon ()
      -- Method: setDaemon ()

          Deprecated getter/setter API for *note daemon: 306.; use it
          directly as a property instead.

          Deprecated since version 3.10.


File: python.info,  Node: Lock objects,  Next: RLock objects,  Prev: Thread objects,  Up: Reference<2>

5.18.1.6 Lock objects
.....................

A primitive lock is a synchronization primitive that is not owned by a
particular thread when locked.  In Python, it is currently the lowest
level synchronization primitive available, implemented directly by the
*note _thread: 2. extension module.

A primitive lock is in one of two states, “locked” or “unlocked”.  It is
created in the unlocked state.  It has two basic methods, *note
acquire(): 69b. and *note release(): 130a.  When the state is unlocked,
‘acquire()’ changes the state to locked and returns immediately.  When
the state is locked, ‘acquire()’ blocks until a call to ‘release()’ in
another thread changes it to unlocked, then the ‘acquire()’ call resets
it to locked and returns.  The ‘release()’ method should only be called
in the locked state; it changes the state to unlocked and returns
immediately.  If an attempt is made to release an unlocked lock, a *note
RuntimeError: 195. will be raised.

Locks also support the *note context management protocol: 331d.

When more than one thread is blocked in *note acquire(): 69b. waiting
for the state to turn to unlocked, only one thread proceeds when a *note
release(): 130a. call resets the state to unlocked; which one of the
waiting threads proceeds is not defined, and may vary across
implementations.

All methods are executed atomically.

 -- Class: threading.Lock

     The class implementing primitive lock objects.  Once a thread has
     acquired a lock, subsequent attempts to acquire it block, until it
     is released; any thread may release it.

     Changed in version 3.13: ‘Lock’ is now a class.  In earlier
     Pythons, ‘Lock’ was a factory function which returned an instance
     of the underlying private lock type.

      -- Method: acquire (blocking=True, timeout=-1)

          Acquire a lock, blocking or non-blocking.

          When invoked with the 'blocking' argument set to ‘True’ (the
          default), block until the lock is unlocked, then set it to
          locked and return ‘True’.

          When invoked with the 'blocking' argument set to ‘False’, do
          not block.  If a call with 'blocking' set to ‘True’ would
          block, return ‘False’ immediately; otherwise, set the lock to
          locked and return ‘True’.

          When invoked with the floating-point 'timeout' argument set to
          a positive value, block for at most the number of seconds
          specified by 'timeout' and as long as the lock cannot be
          acquired.  A 'timeout' argument of ‘-1’ specifies an unbounded
          wait.  It is forbidden to specify a 'timeout' when 'blocking'
          is ‘False’.

          The return value is ‘True’ if the lock is acquired
          successfully, ‘False’ if not (for example if the 'timeout'
          expired).

          Changed in version 3.2: The 'timeout' parameter is new.

          Changed in version 3.2: Lock acquisition can now be
          interrupted by signals on POSIX if the underlying threading
          implementation supports it.

      -- Method: release ()

          Release a lock.  This can be called from any thread, not only
          the thread which has acquired the lock.

          When the lock is locked, reset it to unlocked, and return.  If
          any other threads are blocked waiting for the lock to become
          unlocked, allow exactly one of them to proceed.

          When invoked on an unlocked lock, a *note RuntimeError: 195.
          is raised.

          There is no return value.

      -- Method: locked ()

          Return ‘True’ if the lock is acquired.


File: python.info,  Node: RLock objects,  Next: Condition objects,  Prev: Lock objects,  Up: Reference<2>

5.18.1.7 RLock objects
......................

A reentrant lock is a synchronization primitive that may be acquired
multiple times by the same thread.  Internally, it uses the concepts of
“owning thread” and “recursion level” in addition to the locked/unlocked
state used by primitive locks.  In the locked state, some thread owns
the lock; in the unlocked state, no thread owns it.

Threads call a lock’s *note acquire(): eaf. method to lock it, and its
*note release(): 130a. method to unlock it.

     Note: Reentrant locks support the *note context management
     protocol: 331d, so it is recommended to use *note with: 5d5.
     instead of manually calling *note acquire(): eaf. and *note
     release(): 3321. to handle acquiring and releasing the lock for a
     block of code.

RLock’s *note acquire(): eaf./*note release(): 3321. call pairs may be
nested, unlike Lock’s *note acquire(): 69b./*note release(): 130a.  Only
the final ‘release()’ (the ‘release()’ of the outermost pair) resets the
lock to an unlocked state and allows another thread blocked in
‘acquire()’ to proceed.

*note acquire(): eaf./*note release(): 3321. must be used in pairs: each
acquire must have a release in the thread that has acquired the lock.
Failing to call release as many times the lock has been acquired can
lead to deadlock.

 -- Class: threading.RLock

     This class implements reentrant lock objects.  A reentrant lock
     must be released by the thread that acquired it.  Once a thread has
     acquired a reentrant lock, the same thread may acquire it again
     without blocking; the thread must release it once for each time it
     has acquired it.

     Note that ‘RLock’ is actually a factory function which returns an
     instance of the most efficient version of the concrete RLock class
     that is supported by the platform.

      -- Method: acquire (blocking=True, timeout=-1)

          Acquire a lock, blocking or non-blocking.

          See also
          ........

          *note Using RLock as a context manager: 331d.

               Recommended over manual ‘acquire()’ and *note release():
               3321. calls whenever practical.

          When invoked with the 'blocking' argument set to ‘True’ (the
          default):

                  * If no thread owns the lock, acquire the lock and
                    return immediately.

                  * If another thread owns the lock, block until we are
                    able to acquire lock, or 'timeout', if set to a
                    positive float value.

                  * If the same thread owns the lock, acquire the lock
                    again, and return immediately.  This is the
                    difference between *note Lock: 178a. and ‘RLock’;
                    ‘Lock’ handles this case the same as the previous,
                    blocking until the lock can be acquired.

          When invoked with the 'blocking' argument set to ‘False’:

                  * If no thread owns the lock, acquire the lock and
                    return immediately.

                  * If another thread owns the lock, return immediately.

                  * If the same thread owns the lock, acquire the lock
                    again and return immediately.

          In all cases, if the thread was able to acquire the lock,
          return ‘True’.  If the thread was unable to acquire the lock
          (i.e.  if not blocking or the timeout was reached) return
          ‘False’.

          If called multiple times, failing to call *note release():
          3321. as many times may lead to deadlock.  Consider using
          ‘RLock’ as a context manager rather than calling
          acquire/release directly.

          Changed in version 3.2: The 'timeout' parameter is new.

      -- Method: release ()

          Release a lock, decrementing the recursion level.  If after
          the decrement it is zero, reset the lock to unlocked (not
          owned by any thread), and if any other threads are blocked
          waiting for the lock to become unlocked, allow exactly one of
          them to proceed.  If after the decrement the recursion level
          is still nonzero, the lock remains locked and owned by the
          calling thread.

          Only call this method when the calling thread owns the lock.
          A *note RuntimeError: 195. is raised if this method is called
          when the lock is not acquired.

          There is no return value.


File: python.info,  Node: Condition objects,  Next: Semaphore objects,  Prev: RLock objects,  Up: Reference<2>

5.18.1.8 Condition objects
..........................

A condition variable is always associated with some kind of lock; this
can be passed in or one will be created by default.  Passing one in is
useful when several condition variables must share the same lock.  The
lock is part of the condition object: you don’t have to track it
separately.

A condition variable obeys the *note context management protocol: 331d.:
using the ‘with’ statement acquires the associated lock for the duration
of the enclosed block.  The *note acquire(): 3324. and *note release():
3325. methods also call the corresponding methods of the associated
lock.

Other methods must be called with the associated lock held.  The *note
wait(): 1a0c. method releases the lock, and then blocks until another
thread awakens it by calling *note notify(): 190c. or *note
notify_all(): 303.  Once awakened, ‘wait()’ re-acquires the lock and
returns.  It is also possible to specify a timeout.

The *note notify(): 190c. method wakes up one of the threads waiting for
the condition variable, if any are waiting.  The *note notify_all():
303. method wakes up all threads waiting for the condition variable.

Note: the *note notify(): 190c. and *note notify_all(): 303. methods
don’t release the lock; this means that the thread or threads awakened
will not return from their *note wait(): 1a0c. call immediately, but
only when the thread that called ‘notify()’ or ‘notify_all()’ finally
relinquishes ownership of the lock.

The typical programming style using condition variables uses the lock to
synchronize access to some shared state; threads that are interested in
a particular change of state call *note wait(): 1a0c. repeatedly until
they see the desired state, while threads that modify the state call
*note notify(): 190c. or *note notify_all(): 303. when they change the
state in such a way that it could possibly be a desired state for one of
the waiters.  For example, the following code is a generic
producer-consumer situation with unlimited buffer capacity:

     # Consume one item
     with cv:
         while not an_item_is_available():
             cv.wait()
         get_an_available_item()

     # Produce one item
     with cv:
         make_an_item_available()
         cv.notify()

The ‘while’ loop checking for the application’s condition is necessary
because *note wait(): 1a0c. can return after an arbitrary long time, and
the condition which prompted the *note notify(): 190c. call may no
longer hold true.  This is inherent to multi-threaded programming.  The
*note wait_for(): 3326. method can be used to automate the condition
checking, and eases the computation of timeouts:

     # Consume an item
     with cv:
         cv.wait_for(an_item_is_available)
         get_an_available_item()

To choose between *note notify(): 190c. and *note notify_all(): 303,
consider whether one state change can be interesting for only one or
several waiting threads.  E.g.  in a typical producer-consumer
situation, adding one item to the buffer only needs to wake up one
consumer thread.

 -- Class: threading.Condition (lock=None)

     This class implements condition variable objects.  A condition
     variable allows one or more threads to wait until they are notified
     by another thread.

     If the 'lock' argument is given and not ‘None’, it must be a *note
     Lock: 178a. or *note RLock: 2de. object, and it is used as the
     underlying lock.  Otherwise, a new ‘RLock’ object is created and
     used as the underlying lock.

     Changed in version 3.3: changed from a factory function to a class.

      -- Method: acquire (*args)

          Acquire the underlying lock.  This method calls the
          corresponding method on the underlying lock; the return value
          is whatever that method returns.

      -- Method: release ()

          Release the underlying lock.  This method calls the
          corresponding method on the underlying lock; there is no
          return value.

      -- Method: wait (timeout=None)

          Wait until notified or until a timeout occurs.  If the calling
          thread has not acquired the lock when this method is called, a
          *note RuntimeError: 195. is raised.

          This method releases the underlying lock, and then blocks
          until it is awakened by a *note notify(): 190c. or *note
          notify_all(): 303. call for the same condition variable in
          another thread, or until the optional timeout occurs.  Once
          awakened or timed out, it re-acquires the lock and returns.

          When the 'timeout' argument is present and not ‘None’, it
          should be a floating-point number specifying a timeout for the
          operation in seconds (or fractions thereof).

          When the underlying lock is an *note RLock: 2de, it is not
          released using its *note release(): 3325. method, since this
          may not actually unlock the lock when it was acquired multiple
          times recursively.  Instead, an internal interface of the
          ‘RLock’ class is used, which really unlocks it even when it
          has been recursively acquired several times.  Another internal
          interface is then used to restore the recursion level when the
          lock is reacquired.

          The return value is ‘True’ unless a given 'timeout' expired,
          in which case it is ‘False’.

          Changed in version 3.2: Previously, the method always returned
          ‘None’.

      -- Method: wait_for (predicate, timeout=None)

          Wait until a condition evaluates to true.  'predicate' should
          be a callable which result will be interpreted as a boolean
          value.  A 'timeout' may be provided giving the maximum time to
          wait.

          This utility method may call *note wait(): 1a0c. repeatedly
          until the predicate is satisfied, or until a timeout occurs.
          The return value is the last return value of the predicate and
          will evaluate to ‘False’ if the method timed out.

          Ignoring the timeout feature, calling this method is roughly
          equivalent to writing:

               while not predicate():
                   cv.wait()

          Therefore, the same rules apply as with *note wait(): 1a0c.:
          The lock must be held when called and is re-acquired on
          return.  The predicate is evaluated with the lock held.

          Added in version 3.2.

      -- Method: notify (n=1)

          By default, wake up one thread waiting on this condition, if
          any.  If the calling thread has not acquired the lock when
          this method is called, a *note RuntimeError: 195. is raised.

          This method wakes up at most 'n' of the threads waiting for
          the condition variable; it is a no-op if no threads are
          waiting.

          The current implementation wakes up exactly 'n' threads, if at
          least 'n' threads are waiting.  However, it’s not safe to rely
          on this behavior.  A future, optimized implementation may
          occasionally wake up more than 'n' threads.

          Note: an awakened thread does not actually return from its
          *note wait(): 1a0c. call until it can reacquire the lock.
          Since ‘notify()’ does not release the lock, its caller should.

      -- Method: notify_all ()

          Wake up all threads waiting on this condition.  This method
          acts like *note notify(): 190c, but wakes up all waiting
          threads instead of one.  If the calling thread has not
          acquired the lock when this method is called, a *note
          RuntimeError: 195. is raised.

          The method ‘notifyAll’ is a deprecated alias for this method.


File: python.info,  Node: Semaphore objects,  Next: Semaphore example,  Prev: Condition objects,  Up: Reference<2>

5.18.1.9 Semaphore objects
..........................

This is one of the oldest synchronization primitives in the history of
computer science, invented by the early Dutch computer scientist Edsger
W. Dijkstra (he used the names ‘P()’ and ‘V()’ instead of *note
acquire(): 129a. and *note release(): 3329.).

A semaphore manages an internal counter which is decremented by each
*note acquire(): 129a. call and incremented by each *note release():
3329. call.  The counter can never go below zero; when ‘acquire()’ finds
that it is zero, it blocks, waiting until some other thread calls
‘release()’.

Semaphores also support the *note context management protocol: 331d.

 -- Class: threading.Semaphore (value=1)

     This class implements semaphore objects.  A semaphore manages an
     atomic counter representing the number of *note release(): 3329.
     calls minus the number of *note acquire(): 129a. calls, plus an
     initial value.  The ‘acquire()’ method blocks if necessary until it
     can return without making the counter negative.  If not given,
     'value' defaults to 1.

     The optional argument gives the initial 'value' for the internal
     counter; it defaults to ‘1’.  If the 'value' given is less than 0,
     *note ValueError: 202. is raised.

     Changed in version 3.3: changed from a factory function to a class.

      -- Method: acquire (blocking=True, timeout=None)

          Acquire a semaphore.

          When invoked without arguments:

             * If the internal counter is larger than zero on entry,
               decrement it by one and return ‘True’ immediately.

             * If the internal counter is zero on entry, block until
               awoken by a call to *note release(): 3329.  Once awoken
               (and the counter is greater than 0), decrement the
               counter by 1 and return ‘True’.  Exactly one thread will
               be awoken by each call to ‘release()’.  The order in
               which threads are awoken should not be relied on.

          When invoked with 'blocking' set to ‘False’, do not block.  If
          a call without an argument would block, return ‘False’
          immediately; otherwise, do the same thing as when called
          without arguments, and return ‘True’.

          When invoked with a 'timeout' other than ‘None’, it will block
          for at most 'timeout' seconds.  If acquire does not complete
          successfully in that interval, return ‘False’.  Return ‘True’
          otherwise.

          Changed in version 3.2: The 'timeout' parameter is new.

      -- Method: release (n=1)

          Release a semaphore, incrementing the internal counter by 'n'.
          When it was zero on entry and other threads are waiting for it
          to become larger than zero again, wake up 'n' of those
          threads.

          Changed in version 3.9: Added the 'n' parameter to release
          multiple waiting threads at once.

 -- Class: threading.BoundedSemaphore (value=1)

     Class implementing bounded semaphore objects.  A bounded semaphore
     checks to make sure its current value doesn’t exceed its initial
     value.  If it does, *note ValueError: 202. is raised.  In most
     situations semaphores are used to guard resources with limited
     capacity.  If the semaphore is released too many times it’s a sign
     of a bug.  If not given, 'value' defaults to 1.

     Changed in version 3.3: changed from a factory function to a class.


File: python.info,  Node: Semaphore example,  Next: Event objects,  Prev: Semaphore objects,  Up: Reference<2>

5.18.1.10 ‘Semaphore’ example
.............................

Semaphores are often used to guard resources with limited capacity, for
example, a database server.  In any situation where the size of the
resource is fixed, you should use a bounded semaphore.  Before spawning
any worker threads, your main thread would initialize the semaphore:

     maxconnections = 5
     # ...
     pool_sema = BoundedSemaphore(value=maxconnections)

Once spawned, worker threads call the semaphore’s acquire and release
methods when they need to connect to the server:

     with pool_sema:
         conn = connectdb()
         try:
             # ... use connection ...
         finally:
             conn.close()

The use of a bounded semaphore reduces the chance that a programming
error which causes the semaphore to be released more than it’s acquired
will go undetected.


File: python.info,  Node: Event objects,  Next: Timer objects,  Prev: Semaphore example,  Up: Reference<2>

5.18.1.11 Event objects
.......................

This is one of the simplest mechanisms for communication between
threads: one thread signals an event and other threads wait for it.

An event object manages an internal flag that can be set to true with
the *note set(): 332e. method and reset to false with the *note clear():
332f. method.  The *note wait(): 1370. method blocks until the flag is
true.

 -- Class: threading.Event

     Class implementing event objects.  An event manages a flag that can
     be set to true with the *note set(): 332e. method and reset to
     false with the *note clear(): 332f. method.  The *note wait():
     1370. method blocks until the flag is true.  The flag is initially
     false.

     Changed in version 3.3: changed from a factory function to a class.

      -- Method: is_set ()

          Return ‘True’ if and only if the internal flag is true.

          The method ‘isSet’ is a deprecated alias for this method.

      -- Method: set ()

          Set the internal flag to true.  All threads waiting for it to
          become true are awakened.  Threads that call *note wait():
          1370. once the flag is true will not block at all.

      -- Method: clear ()

          Reset the internal flag to false.  Subsequently, threads
          calling *note wait(): 1370. will block until *note set():
          332e. is called to set the internal flag to true again.

      -- Method: wait (timeout=None)

          Block as long as the internal flag is false and the timeout,
          if given, has not expired.  The return value represents the
          reason that this blocking method returned; ‘True’ if returning
          because the internal flag is set to true, or ‘False’ if a
          timeout is given and the internal flag did not become true
          within the given wait time.

          When the timeout argument is present and not ‘None’, it should
          be a floating-point number specifying a timeout for the
          operation in seconds, or fractions thereof.

          Changed in version 3.1: Previously, the method always returned
          ‘None’.


File: python.info,  Node: Timer objects,  Next: Barrier objects,  Prev: Event objects,  Up: Reference<2>

5.18.1.12 Timer objects
.......................

This class represents an action that should be run only after a certain
amount of time has passed — a timer.  *note Timer: 119d. is a subclass
of *note Thread: 956. and as such also functions as an example of
creating custom threads.

Timers are started, as with threads, by calling their *note Timer.start:
2ea8. method.  The timer can be stopped (before its action has begun) by
calling the *note cancel(): 3332. method.  The interval the timer will
wait before executing its action may not be exactly the same as the
interval specified by the user.

For example:

     def hello():
         print("hello, world")

     t = Timer(30.0, hello)
     t.start()  # after 30 seconds, "hello, world" will be printed

 -- Class: threading.Timer (interval, function, args=None, kwargs=None)

     Create a timer that will run 'function' with arguments 'args' and
     keyword arguments 'kwargs', after 'interval' seconds have passed.
     If 'args' is ‘None’ (the default) then an empty list will be used.
     If 'kwargs' is ‘None’ (the default) then an empty dict will be
     used.

     Changed in version 3.3: changed from a factory function to a class.

      -- Method: cancel ()

          Stop the timer, and cancel the execution of the timer’s
          action.  This will only work if the timer is still in its
          waiting stage.


File: python.info,  Node: Barrier objects,  Prev: Timer objects,  Up: Reference<2>

5.18.1.13 Barrier objects
.........................

Added in version 3.2.

This class provides a simple synchronization primitive for use by a
fixed number of threads that need to wait for each other.  Each of the
threads tries to pass the barrier by calling the *note wait(): 3334.
method and will block until all of the threads have made their ‘wait()’
calls.  At this point, the threads are released simultaneously.

The barrier can be reused any number of times for the same number of
threads.

As an example, here is a simple way to synchronize a client and server
thread:

     b = Barrier(2, timeout=5)

     def server():
         start_server()
         b.wait()
         while True:
             connection = accept_connection()
             process_server_connection(connection)

     def client():
         b.wait()
         while True:
             connection = make_connection()
             process_client_connection(connection)

 -- Class: threading.Barrier (parties, action=None, timeout=None)

     Create a barrier object for 'parties' number of threads.  An
     'action', when provided, is a callable to be called by one of the
     threads when they are released.  'timeout' is the default timeout
     value if none is specified for the *note wait(): 3334. method.

      -- Method: wait (timeout=None)

          Pass the barrier.  When all the threads party to the barrier
          have called this function, they are all released
          simultaneously.  If a 'timeout' is provided, it is used in
          preference to any that was supplied to the class constructor.

          The return value is an integer in the range 0 to 'parties' –
          1, different for each thread.  This can be used to select a
          thread to do some special housekeeping, e.g.:

               i = barrier.wait()
               if i == 0:
                   # Only one thread needs to print this
                   print("passed the barrier")

          If an 'action' was provided to the constructor, one of the
          threads will have called it prior to being released.  Should
          this call raise an error, the barrier is put into the broken
          state.

          If the call times out, the barrier is put into the broken
          state.

          This method may raise a *note BrokenBarrierError: 122a.
          exception if the barrier is broken or reset while a thread is
          waiting.

      -- Method: reset ()

          Return the barrier to the default, empty state.  Any threads
          waiting on it will receive the *note BrokenBarrierError: 122a.
          exception.

          Note that using this function may require some external
          synchronization if there are other threads whose state is
          unknown.  If a barrier is broken it may be better to just
          leave it and create a new one.

      -- Method: abort ()

          Put the barrier into a broken state.  This causes any active
          or future calls to *note wait(): 3334. to fail with the *note
          BrokenBarrierError: 122a.  Use this for example if one of the
          threads needs to abort, to avoid deadlocking the application.

          It may be preferable to simply create the barrier with a
          sensible 'timeout' value to automatically guard against one of
          the threads going awry.

      -- Attribute: parties

          The number of threads required to pass the barrier.

      -- Attribute: n_waiting

          The number of threads currently waiting in the barrier.

      -- Attribute: broken

          A boolean that is ‘True’ if the barrier is in the broken
          state.

 -- Exception: threading.BrokenBarrierError

     This exception, a subclass of *note RuntimeError: 195, is raised
     when the *note Barrier: 1228. object is reset or broken.


File: python.info,  Node: Using locks conditions and semaphores in the with statement,  Prev: Reference<2>,  Up: threading — Thread-based parallelism

5.18.1.14 Using locks, conditions, and semaphores in the ‘with’ statement
.........................................................................

All of the objects provided by this module that have ‘acquire’ and
‘release’ methods can be used as context managers for a *note with: 5d5.
statement.  The ‘acquire’ method will be called when the block is
entered, and ‘release’ will be called when the block is exited.  Hence,
the following snippet:

     with some_lock:
         # do something...

is equivalent to:

     some_lock.acquire()
     try:
         # do something...
     finally:
         some_lock.release()

Currently, *note Lock: 178a, *note RLock: 2de, *note Condition: 1199,
*note Semaphore: 119a, and *note BoundedSemaphore: 119b. objects may be
used as *note with: 5d5. statement context managers.


File: python.info,  Node: multiprocessing — Process-based parallelism,  Next: multiprocessing shared_memory — Shared memory for direct access across processes,  Prev: threading — Thread-based parallelism,  Up: Concurrent Execution

5.18.2 ‘multiprocessing’ — Process-based parallelism
----------------------------------------------------

'Source code:' Lib/multiprocessing/(1)

__________________________________________________________________

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

* Menu:

* Introduction: Introduction<9>.
* Reference: Reference<3>.
* Programming guidelines::
* Examples: Examples<14>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/multiprocessing/


File: python.info,  Node: Introduction<9>,  Next: Reference<3>,  Up: multiprocessing — Process-based parallelism

5.18.2.1 Introduction
.....................

‘multiprocessing’ is a package that supports spawning processes using an
API similar to the *note threading: ed. module.  The ‘multiprocessing’
package offers both local and remote concurrency, effectively
side-stepping the *note Global Interpreter Lock: 148. by using
subprocesses instead of threads.  Due to this, the ‘multiprocessing’
module allows the programmer to fully leverage multiple processors on a
given machine.  It runs on both POSIX and Windows.

The ‘multiprocessing’ module also introduces the *note Pool: fa4. object
which offers a convenient means of parallelizing the execution of a
function across multiple input values, distributing the input data
across processes (data parallelism).  The following example demonstrates
the common practice of defining such functions in a module so that child
processes can successfully import that module.  This basic example of
data parallelism using ‘Pool’,

     from multiprocessing import Pool

     def f(x):
         return x*x

     if __name__ == '__main__':
         with Pool(5) as p:
             print(p.map(f, [1, 2, 3]))

will print to standard output

     [1, 4, 9]

The ‘multiprocessing’ module also introduces APIs which do not have
analogs in the *note threading: ed. module, like the ability to *note
terminate: 333f, ‘interrupt’ or *note kill: b73. a running process.

See also
........

*note concurrent.futures.ProcessPoolExecutor: 8f7. offers a higher level
interface to push tasks to a background process without blocking
execution of the calling process.  Compared to using the *note Pool:
fa4. interface directly, the *note concurrent.futures: 21. API more
readily allows the submission of work to the underlying process pool to
be separated from waiting for the results.

* Menu:

* The Process class::
* Contexts and start methods::
* Exchanging objects between processes::
* Synchronization between processes::
* Sharing state between processes::
* Using a pool of workers::


File: python.info,  Node: The Process class,  Next: Contexts and start methods,  Up: Introduction<9>

5.18.2.2 The ‘Process’ class
............................

In ‘multiprocessing’, processes are spawned by creating a *note Process:
b75. object and then calling its *note start(): 13de. method.  ‘Process’
follows the API of *note threading.Thread: 956.  A trivial example of a
multiprocess program is

     from multiprocessing import Process

     def f(name):
         print('hello', name)

     if __name__ == '__main__':
         p = Process(target=f, args=('bob',))
         p.start()
         p.join()

To show the individual process IDs involved, here is an expanded
example:

     from multiprocessing import Process
     import os

     def info(title):
         print(title)
         print('module name:', __name__)
         print('parent process:', os.getppid())
         print('process id:', os.getpid())

     def f(name):
         info('function f')
         print('hello', name)

     if __name__ == '__main__':
         info('main line')
         p = Process(target=f, args=('bob',))
         p.start()
         p.join()

For an explanation of why the ‘if __name__ == '__main__'’ part is
necessary, see *note Programming guidelines: 3341.

The arguments to *note Process: b75. usually need to be unpickleable
from within the child process.  If you tried typing the above example
directly into a REPL it could lead to an *note AttributeError: 34e. in
the child process trying to locate the 'f' function in the ‘__main__’
module.


File: python.info,  Node: Contexts and start methods,  Next: Exchanging objects between processes,  Prev: The Process class,  Up: Introduction<9>

5.18.2.3 Contexts and start methods
...................................

Depending on the platform, ‘multiprocessing’ supports three ways to
start a process.  These 'start methods' are

     'spawn'

          The parent process starts a fresh Python interpreter process.
          The child process will only inherit those resources necessary
          to run the process object’s *note run(): 3344. method.  In
          particular, unnecessary file descriptors and handles from the
          parent process will not be inherited.  Starting a process
          using this method is rather slow compared to using 'fork' or
          'forkserver'.

          Available on POSIX and Windows platforms.  The default on
          Windows and macOS.

     'fork'

          The parent process uses *note os.fork(): 197. to fork the
          Python interpreter.  The child process, when it begins, is
          effectively identical to the parent process.  All resources of
          the parent are inherited by the child process.  Note that
          safely forking a multithreaded process is problematic.

          Available on POSIX systems.  Currently the default on POSIX
          except macOS.

               Note: The default start method will change away from
               'fork' in Python 3.14.  Code that requires 'fork' should
               explicitly specify that via *note get_context(): 2c6. or
               *note set_start_method(): 2c7.

          Changed in version 3.12: If Python is able to detect that your
          process has multiple threads, the *note os.fork(): 197.
          function that this start method calls internally will raise a
          *note DeprecationWarning: 1a5.  Use a different start method.
          See the ‘os.fork()’ documentation for further explanation.

     'forkserver'

          When the program starts and selects the 'forkserver' start
          method, a server process is spawned.  From then on, whenever a
          new process is needed, the parent process connects to the
          server and requests that it fork a new process.  The fork
          server process is single threaded unless system libraries or
          preloaded imports spawn threads as a side-effect so it is
          generally safe for it to use *note os.fork(): 197.  No
          unnecessary resources are inherited.

          Available on POSIX platforms which support passing file
          descriptors over Unix pipes such as Linux.

Changed in version 3.4: 'spawn' added on all POSIX platforms, and
'forkserver' added for some POSIX platforms.  Child processes no longer
inherit all of the parents inheritable handles on Windows.

Changed in version 3.8: On macOS, the 'spawn' start method is now the
default.  The 'fork' start method should be considered unsafe as it can
lead to crashes of the subprocess as macOS system libraries may start
threads.  See bpo-33725(1).

On POSIX using the 'spawn' or 'forkserver' start methods will also start
a 'resource tracker' process which tracks the unlinked named system
resources (such as named semaphores or *note SharedMemory: 176c.
objects) created by processes of the program.  When all processes have
exited the resource tracker unlinks any remaining tracked object.
Usually there should be none, but if a process was killed by a signal
there may be some “leaked” resources.  (Neither leaked semaphores nor
shared memory segments will be automatically unlinked until the next
reboot.  This is problematic for both objects because the system allows
only a limited number of named semaphores, and shared memory segments
occupy some space in the main memory.)

To select a start method you use the *note set_start_method(): 2c7. in
the ‘if __name__ == '__main__'’ clause of the main module.  For example:

     import multiprocessing as mp

     def foo(q):
         q.put('hello')

     if __name__ == '__main__':
         mp.set_start_method('spawn')
         q = mp.Queue()
         p = mp.Process(target=foo, args=(q,))
         p.start()
         print(q.get())
         p.join()

*note set_start_method(): 2c7. should not be used more than once in the
program.

Alternatively, you can use *note get_context(): 2c6. to obtain a context
object.  Context objects have the same API as the multiprocessing
module, and allow one to use multiple start methods in the same program.

     import multiprocessing as mp

     def foo(q):
         q.put('hello')

     if __name__ == '__main__':
         ctx = mp.get_context('spawn')
         q = ctx.Queue()
         p = ctx.Process(target=foo, args=(q,))
         p.start()
         print(q.get())
         p.join()

Note that objects related to one context may not be compatible with
processes for a different context.  In particular, locks created using
the 'fork' context cannot be passed to processes started using the
'spawn' or 'forkserver' start methods.

Libraries using ‘multiprocessing’ or *note ProcessPoolExecutor: 8f7.
should be designed to allow their users to provide their own
multiprocessing context.  Using a specific context of your own within a
library can lead to incompatibilities with the rest of the library
user’s application.  Always document if your library requires a specific
start method.

     Warning: The ‘'spawn'’ and ‘'forkserver'’ start methods generally
     cannot be used with “frozen” executables (i.e., binaries produced
     by packages like 'PyInstaller' and 'cx_Freeze') on POSIX systems.
     The ‘'fork'’ start method may work if code does not use threads.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33725


File: python.info,  Node: Exchanging objects between processes,  Next: Synchronization between processes,  Prev: Contexts and start methods,  Up: Introduction<9>

5.18.2.4 Exchanging objects between processes
.............................................

‘multiprocessing’ supports two types of communication channel between
processes:

'Queues'

     The *note Queue: 192f. class is a near clone of *note queue.Queue:
     13e1.  For example:

          from multiprocessing import Process, Queue

          def f(q):
              q.put([42, None, 'hello'])

          if __name__ == '__main__':
              q = Queue()
              p = Process(target=f, args=(q,))
              p.start()
              print(q.get())    # prints "[42, None, 'hello']"
              p.join()

     Queues are thread and process safe.  Any object put into a
     ‘multiprocessing’ queue will be serialized.

'Pipes'

     The *note Pipe(): 3348. function returns a pair of connection
     objects connected by a pipe which by default is duplex (two-way).
     For example:

          from multiprocessing import Process, Pipe

          def f(conn):
              conn.send([42, None, 'hello'])
              conn.close()

          if __name__ == '__main__':
              parent_conn, child_conn = Pipe()
              p = Process(target=f, args=(child_conn,))
              p.start()
              print(parent_conn.recv())   # prints "[42, None, 'hello']"
              p.join()

     The two connection objects returned by *note Pipe(): 3348.
     represent the two ends of the pipe.  Each connection object has
     ‘send()’ and ‘recv()’ methods (among others).  Note that data in a
     pipe may become corrupted if two processes (or threads) try to read
     from or write to the 'same' end of the pipe at the same time.  Of
     course there is no risk of corruption from processes using
     different ends of the pipe at the same time.

     The ‘send()’ method serializes the object and ‘recv()’ re-creates
     the object.


File: python.info,  Node: Synchronization between processes,  Next: Sharing state between processes,  Prev: Exchanging objects between processes,  Up: Introduction<9>

5.18.2.5 Synchronization between processes
..........................................

‘multiprocessing’ contains equivalents of all the synchronization
primitives from *note threading: ed.  For instance one can use a lock to
ensure that only one process prints to standard output at a time:

     from multiprocessing import Process, Lock

     def f(l, i):
         l.acquire()
         try:
             print('hello world', i)
         finally:
             l.release()

     if __name__ == '__main__':
         lock = Lock()

         for num in range(10):
             Process(target=f, args=(lock, num)).start()

Without using the lock output from the different processes is liable to
get all mixed up.


File: python.info,  Node: Sharing state between processes,  Next: Using a pool of workers,  Prev: Synchronization between processes,  Up: Introduction<9>

5.18.2.6 Sharing state between processes
........................................

As mentioned above, when doing concurrent programming it is usually best
to avoid using shared state as far as possible.  This is particularly
true when using multiple processes.

However, if you really do need to use some shared data then
‘multiprocessing’ provides a couple of ways of doing so.

'Shared memory'

     Data can be stored in a shared memory map using *note Value: 334b.
     or *note Array: 334c.  For example, the following code

          from multiprocessing import Process, Value, Array

          def f(n, a):
              n.value = 3.1415927
              for i in range(len(a)):
                  a[i] = -a[i]

          if __name__ == '__main__':
              num = Value('d', 0.0)
              arr = Array('i', range(10))

              p = Process(target=f, args=(num, arr))
              p.start()
              p.join()

              print(num.value)
              print(arr[:])

     will print

          3.1415927
          [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]

     The ‘'d'’ and ‘'i'’ arguments used when creating ‘num’ and ‘arr’
     are typecodes of the kind used by the *note array: 7. module: ‘'d'’
     indicates a double precision float and ‘'i'’ indicates a signed
     integer.  These shared objects will be process and thread-safe.

     For more flexibility in using shared memory one can use the *note
     multiprocessing.sharedctypes: 9a. module which supports the
     creation of arbitrary ctypes objects allocated from shared memory.

'Server process'

     A manager object returned by *note Manager(): ce0. controls a
     server process which holds Python objects and allows other
     processes to manipulate them using proxies.

     A manager returned by *note Manager(): ce0. will support types
     *note list: 614, *note dict: 256, *note Namespace: 334d, *note
     Lock: 16a2, *note RLock: 15c1, *note Semaphore: 334e, *note
     BoundedSemaphore: 334f, *note Condition: 3350, *note Event: 19aa,
     *note Barrier: 3351, *note Queue: 192f, *note Value: 334b. and
     *note Array: 334c.  For example,

          from multiprocessing import Process, Manager

          def f(d, l):
              d[1] = '1'
              d['2'] = 2
              d[0.25] = None
              l.reverse()

          if __name__ == '__main__':
              with Manager() as manager:
                  d = manager.dict()
                  l = manager.list(range(10))

                  p = Process(target=f, args=(d, l))
                  p.start()
                  p.join()

                  print(d)
                  print(l)

     will print

          {0.25: None, 1: '1', '2': 2}
          [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]

     Server process managers are more flexible than using shared memory
     objects because they can be made to support arbitrary object types.
     Also, a single manager can be shared by processes on different
     computers over a network.  They are, however, slower than using
     shared memory.


File: python.info,  Node: Using a pool of workers,  Prev: Sharing state between processes,  Up: Introduction<9>

5.18.2.7 Using a pool of workers
................................

The *note Pool: fa4. class represents a pool of worker processes.  It
has methods which allows tasks to be offloaded to the worker processes
in a few different ways.

For example:

     from multiprocessing import Pool, TimeoutError
     import time
     import os

     def f(x):
         return x*x

     if __name__ == '__main__':
         # start 4 worker processes
         with Pool(processes=4) as pool:

             # print "[0, 1, 4,..., 81]"
             print(pool.map(f, range(10)))

             # print same numbers in arbitrary order
             for i in pool.imap_unordered(f, range(10)):
                 print(i)

             # evaluate "f(20)" asynchronously
             res = pool.apply_async(f, (20,))      # runs in *only* one process
             print(res.get(timeout=1))             # prints "400"

             # evaluate "os.getpid()" asynchronously
             res = pool.apply_async(os.getpid, ()) # runs in *only* one process
             print(res.get(timeout=1))             # prints the PID of that process

             # launching multiple evaluations asynchronously *may* use more processes
             multiple_results = [pool.apply_async(os.getpid, ()) for i in range(4)]
             print([res.get(timeout=1) for res in multiple_results])

             # make a single worker sleep for 10 seconds
             res = pool.apply_async(time.sleep, (10,))
             try:
                 print(res.get(timeout=1))
             except TimeoutError:
                 print("We lacked patience and got a multiprocessing.TimeoutError")

             print("For the moment, the pool remains available for more work")

         # exiting the 'with'-block has stopped the pool
         print("Now the pool is closed and no longer available")

Note that the methods of a pool should only ever be used by the process
which created it.

     Note: Functionality within this package requires that the
     ‘__main__’ module be importable by the children.  This is covered
     in *note Programming guidelines: 3341. however it is worth pointing
     out here.  This means that some examples, such as the *note
     multiprocessing.pool.Pool: fa4. examples will not work in the
     interactive interpreter.  For example:

          >>> from multiprocessing import Pool
          >>> p = Pool(5)
          >>> def f(x):
          ...     return x*x
          ...
          >>> with p:
          ...     p.map(f, [1,2,3])
          Process PoolWorker-1:
          Process PoolWorker-2:
          Process PoolWorker-3:
          Traceback (most recent call last):
          Traceback (most recent call last):
          Traceback (most recent call last):
          AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>
          AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>
          AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>

     (If you try this it will actually output three full tracebacks
     interleaved in a semi-random fashion, and then you may have to stop
     the parent process somehow.)


File: python.info,  Node: Reference<3>,  Next: Programming guidelines,  Prev: Introduction<9>,  Up: multiprocessing — Process-based parallelism

5.18.2.8 Reference
..................

The ‘multiprocessing’ package mostly replicates the API of the *note
threading: ed. module.

* Menu:

* Global start method::
* Process and exceptions::
* Pipes and Queues::
* Miscellaneous: Miscellaneous<3>.
* Connection Objects::
* Synchronization primitives::
* Shared ctypes Objects::
* Managers::
* Proxy Objects::
* Process Pools::
* Listeners and Clients::
* Authentication keys::
* Logging: Logging<2>.
* The multiprocessing.dummy module: The multiprocessing dummy module.


File: python.info,  Node: Global start method,  Next: Process and exceptions,  Up: Reference<3>

5.18.2.9 Global start method
............................

Python supports several ways to create and initialize a process.  The
global start method sets the default mechanism for creating a process.

Several multiprocessing functions and methods that may also instantiate
certain objects will implicitly set the global start method to the
system’s default, if it hasn’t been set already.  The global start
method can only be set once.  If you need to change the start method
from the system default, you must proactively set the global start
method before calling functions or methods, or creating these objects.


File: python.info,  Node: Process and exceptions,  Next: Pipes and Queues,  Prev: Global start method,  Up: Reference<3>

5.18.2.10 ‘Process’ and exceptions
..................................

 -- Class: multiprocessing.Process (group=None, target=None, name=None,
          args=(), kwargs={}, *, daemon=None)

     Process objects represent activity that is run in a separate
     process.  The ‘Process’ class has equivalents of all the methods of
     *note threading.Thread: 956.

     The constructor should always be called with keyword arguments.
     'group' should always be ‘None’; it exists solely for compatibility
     with *note threading.Thread: 956.  'target' is the callable object
     to be invoked by the *note run(): 3344. method.  It defaults to
     ‘None’, meaning nothing is called.  'name' is the process name (see
     *note name: 3357. for more details).  'args' is the argument tuple
     for the target invocation.  'kwargs' is a dictionary of keyword
     arguments for the target invocation.  If provided, the keyword-only
     'daemon' argument sets the process *note daemon: 3358. flag to
     ‘True’ or ‘False’.  If ‘None’ (the default), this flag will be
     inherited from the creating process.

     By default, no arguments are passed to 'target'.  The 'args'
     argument, which defaults to ‘()’, can be used to specify a list or
     tuple of the arguments to pass to 'target'.

     If a subclass overrides the constructor, it must make sure it
     invokes the base class constructor (‘super().__init__()’) before
     doing anything else to the process.

          Note: In general, all arguments to ‘Process’ must be
          picklable.  This is frequently observed when trying to create
          a ‘Process’ or use a *note
          concurrent.futures.ProcessPoolExecutor: 8f7. from a REPL with
          a locally defined 'target' function.

          Passing a callable object defined in the current REPL session
          causes the child process to die via an uncaught *note
          AttributeError: 34e. exception when starting as 'target' must
          have been defined within an importable module in order to be
          loaded during unpickling.

          Example of this uncatchable error from the child:

               >>> import multiprocessing as mp
               >>> def knigit():
               ...     print("Ni!")
               ...
               >>> process = mp.Process(target=knigit)
               >>> process.start()
               >>> Traceback (most recent call last):
                 File ".../multiprocessing/spawn.py", line ..., in spawn_main
                 File ".../multiprocessing/spawn.py", line ..., in _main
               AttributeError: module '__main__' has no attribute 'knigit'
               >>> process
               <SpawnProcess name='SpawnProcess-1' pid=379473 parent=378707 stopped exitcode=1>

          See *note The spawn and forkserver start methods: 3359.  While
          this restriction is not true if using the ‘"fork"’ start
          method, as of Python ‘3.14’ that is no longer the default on
          any platform.  See *note Contexts and start methods: 2c8.  See
          also gh-132898(1).

     Changed in version 3.3: Added the 'daemon' parameter.

      -- Method: run ()

          Method representing the process’s activity.

          You may override this method in a subclass.  The standard
          ‘run()’ method invokes the callable object passed to the
          object’s constructor as the target argument, if any, with
          sequential and keyword arguments taken from the 'args' and
          'kwargs' arguments, respectively.

          Using a list or tuple as the 'args' argument passed to
          ‘Process’ achieves the same effect.

          Example:

               >>> from multiprocessing import Process
               >>> p = Process(target=print, args=[1])
               >>> p.run()
               1
               >>> p = Process(target=print, args=(1,))
               >>> p.run()
               1

      -- Method: start ()

          Start the process’s activity.

          This must be called at most once per process object.  It
          arranges for the object’s *note run(): 3344. method to be
          invoked in a separate process.

      -- Method: join ([timeout])

          If the optional argument 'timeout' is ‘None’ (the default),
          the method blocks until the process whose ‘join()’ method is
          called terminates.  If 'timeout' is a positive number, it
          blocks at most 'timeout' seconds.  Note that the method
          returns ‘None’ if its process terminates or if the method
          times out.  Check the process’s *note exitcode: 335a. to
          determine if it terminated.

          A process can be joined many times.

          A process cannot join itself because this would cause a
          deadlock.  It is an error to attempt to join a process before
          it has been started.

      -- Attribute: name

          The process’s name.  The name is a string used for
          identification purposes only.  It has no semantics.  Multiple
          processes may be given the same name.

          The initial name is set by the constructor.  If no explicit
          name is provided to the constructor, a name of the form
          ‘Process-N[1]:N[2]:…:N[k]’ is constructed, where each N[k] is
          the N-th child of its parent.

      -- Method: is_alive ()

          Return whether the process is alive.

          Roughly, a process object is alive from the moment the *note
          start(): 13de. method returns until the child process
          terminates.

      -- Attribute: daemon

          The process’s daemon flag, a Boolean value.  This must be set
          before *note start(): 13de. is called.

          The initial value is inherited from the creating process.

          When a process exits, it attempts to terminate all of its
          daemonic child processes.

          Note that a daemonic process is not allowed to create child
          processes.  Otherwise a daemonic process would leave its
          children orphaned if it gets terminated when its parent
          process exits.  Additionally, these are 'not' Unix daemons or
          services, they are normal processes that will be terminated
          (and not joined) if non-daemonic processes have exited.

     In addition to the *note threading.Thread: 956. API, ‘Process’
     objects also support the following attributes and methods:

      -- Attribute: pid

          Return the process ID. Before the process is spawned, this
          will be ‘None’.

      -- Attribute: exitcode

          The child’s exit code.  This will be ‘None’ if the process has
          not yet terminated.

          If the child’s *note run(): 3344. method returned normally,
          the exit code will be 0.  If it terminated via *note
          sys.exit(): 1394. with an integer argument 'N', the exit code
          will be 'N'.

          If the child terminated due to an exception not caught within
          *note run(): 3344, the exit code will be 1.  If it was
          terminated by signal 'N', the exit code will be the negative
          value '-N'.

      -- Attribute: authkey

          The process’s authentication key (a byte string).

          When ‘multiprocessing’ is initialized the main process is
          assigned a random string using *note os.urandom(): 526.

          When a ‘Process’ object is created, it will inherit the
          authentication key of its parent process, although this may be
          changed by setting *note authkey: 335c. to another byte
          string.

          See *note Authentication keys: 335d.

      -- Attribute: sentinel

          A numeric handle of a system object which will become “ready”
          when the process ends.

          You can use this value if you want to wait on several events
          at once using *note multiprocessing.connection.wait(): 1123.
          Otherwise calling *note join(): 13e0. is simpler.

          On Windows, this is an OS handle usable with the
          ‘WaitForSingleObject’ and ‘WaitForMultipleObjects’ family of
          API calls.  On POSIX, this is a file descriptor usable with
          primitives from the *note select: c1. module.

          Added in version 3.3.

      -- Method: terminate ()

          Terminate the process.  On POSIX this is done using the *note
          SIGTERM: 142d. signal; on Windows ‘TerminateProcess()’ is
          used.  Note that exit handlers and finally clauses, etc., will
          not be executed.

          Note that descendant processes of the process will 'not' be
          terminated – they will simply become orphaned.

               Warning: If this method is used when the associated
               process is using a pipe or queue then the pipe or queue
               is liable to become corrupted and may become unusable by
               other process.  Similarly, if the process has acquired a
               lock or semaphore etc.  then terminating it is liable to
               cause other processes to deadlock.

      -- Method: kill ()

          Same as *note terminate(): 333f. but using the ‘SIGKILL’
          signal on POSIX.

          Added in version 3.7.

      -- Method: close ()

          Close the ‘Process’ object, releasing all resources associated
          with it.  *note ValueError: 202. is raised if the underlying
          process is still running.  Once ‘close()’ returns
          successfully, most other methods and attributes of the
          ‘Process’ object will raise ‘ValueError’.

          Added in version 3.7.

     Note that the *note start(): 13de, *note join(): 13e0, *note
     is_alive(): 13df, *note terminate(): 333f. and *note exitcode:
     335a. methods should only be called by the process that created the
     process object.

     Example usage of some of the methods of ‘Process’:

          >>> import multiprocessing, time, signal
          >>> mp_context = multiprocessing.get_context('spawn')
          >>> p = mp_context.Process(target=time.sleep, args=(1000,))
          >>> print(p, p.is_alive())
          <...Process ... initial> False
          >>> p.start()
          >>> print(p, p.is_alive())
          <...Process ... started> True
          >>> p.terminate()
          >>> time.sleep(0.1)
          >>> print(p, p.is_alive())
          <...Process ... stopped exitcode=-SIGTERM> False
          >>> p.exitcode == -signal.SIGTERM
          True

 -- Exception: multiprocessing.ProcessError

     The base class of all ‘multiprocessing’ exceptions.

 -- Exception: multiprocessing.BufferTooShort

     Exception raised by ‘Connection.recv_bytes_into()’ when the
     supplied buffer object is too small for the message read.

     If ‘e’ is an instance of ‘BufferTooShort’ then ‘e.args[0]’ will
     give the message as a byte string.

 -- Exception: multiprocessing.AuthenticationError

     Raised when there is an authentication error.

 -- Exception: multiprocessing.TimeoutError

     Raised by methods with a timeout when the timeout expires.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/132898


File: python.info,  Node: Pipes and Queues,  Next: Miscellaneous<3>,  Prev: Process and exceptions,  Up: Reference<3>

5.18.2.11 Pipes and Queues
..........................

When using multiple processes, one generally uses message passing for
communication between processes and avoids having to use any
synchronization primitives like locks.

For passing messages one can use *note Pipe(): 3348. (for a connection
between two processes) or a queue (which allows multiple producers and
consumers).

The *note Queue: 192f, *note SimpleQueue: 91d. and *note JoinableQueue:
3363. types are multi-producer, multi-consumer FIFO queues modelled on
the *note queue.Queue: 13e1. class in the standard library.  They differ
in that ‘Queue’ lacks the *note task_done(): 3364. and *note join():
3365. methods introduced into Python 2.5’s ‘queue.Queue’ class.

If you use *note JoinableQueue: 3363. then you 'must' call *note
JoinableQueue.task_done(): 3366. for each task removed from the queue or
else the semaphore used to count the number of unfinished tasks may
eventually overflow, raising an exception.

One difference from other Python queue implementations, is that
‘multiprocessing’ queues serializes all objects that are put into them
using *note pickle: a6.  The object return by the get method is a
re-created object that does not share memory with the original object.

Note that one can also create a shared queue by using a manager object –
see *note Managers: 3367.

     Note: ‘multiprocessing’ uses the usual *note queue.Empty: 3368. and
     *note queue.Full: 3369. exceptions to signal a timeout.  They are
     not available in the ‘multiprocessing’ namespace so you need to
     import them from *note queue: b6.

     Note: When an object is put on a queue, the object is pickled and a
     background thread later flushes the pickled data to an underlying
     pipe.  This has some consequences which are a little surprising,
     but should not cause any practical difficulties – if they really
     bother you then you can instead use a queue created with a *note
     manager: 3367.

       1. After putting an object on an empty queue there may be an
          infinitesimal delay before the queue’s *note empty(): 1704.
          method returns *note False: b4f. and *note get_nowait(): 336a.
          can return without raising *note queue.Empty: 3368.

       2. If multiple processes are enqueuing objects, it is possible
          for the objects to be received at the other end out-of-order.
          However, objects enqueued by the same process will always be
          in the expected order with respect to each other.

     Warning: If a process is killed using *note Process.terminate():
     333f. or *note os.kill(): 13b4. while it is trying to use a *note
     Queue: 192f, then the data in the queue is likely to become
     corrupted.  This may cause any other process to get an exception
     when it tries to use the queue later on.

     Warning: As mentioned above, if a child process has put items on a
     queue (and it has not used *note JoinableQueue.cancel_join_thread:
     336b.), then that process will not terminate until all buffered
     items have been flushed to the pipe.

     This means that if you try joining that process you may get a
     deadlock unless you are sure that all items which have been put on
     the queue have been consumed.  Similarly, if the child process is
     non-daemonic then the parent process may hang on exit when it tries
     to join all its non-daemonic children.

     Note that a queue created using a manager does not have this issue.
     See *note Programming guidelines: 3341.

For an example of the usage of queues for interprocess communication see
*note Examples: 336c.

 -- Function: multiprocessing.Pipe ([duplex])

     Returns a pair ‘(conn1, conn2)’ of *note Connection: 1124. objects
     representing the ends of a pipe.

     If 'duplex' is ‘True’ (the default) then the pipe is bidirectional.
     If 'duplex' is ‘False’ then the pipe is unidirectional: ‘conn1’ can
     only be used for receiving messages and ‘conn2’ can only be used
     for sending messages.

     The ‘send()’ method serializes the object using *note pickle: a6.
     and the ‘recv()’ re-creates the object.

 -- Class: multiprocessing.Queue ([maxsize])

     Returns a process shared queue implemented using a pipe and a few
     locks/semaphores.  When a process first puts an item on the queue a
     feeder thread is started which transfers objects from a buffer into
     the pipe.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     The usual *note queue.Empty: 3368. and *note queue.Full: 3369.
     exceptions from the standard library’s *note queue: b6. module are
     raised to signal timeouts.

     ‘Queue’ implements all the methods of *note queue.Queue: 13e1.
     except for *note task_done(): 3364. and *note join(): 3365.

      -- Method: qsize ()

          Return the approximate size of the queue.  Because of
          multithreading/multiprocessing semantics, this number is not
          reliable.

          Note that this may raise *note NotImplementedError: 228. on
          platforms like macOS where ‘sem_getvalue()’ is not
          implemented.

      -- Method: empty ()

          Return ‘True’ if the queue is empty, ‘False’ otherwise.
          Because of multithreading/multiprocessing semantics, this is
          not reliable.

          May raise an *note OSError: 41a. on closed queues.  (not
          guaranteed)

      -- Method: full ()

          Return ‘True’ if the queue is full, ‘False’ otherwise.
          Because of multithreading/multiprocessing semantics, this is
          not reliable.

      -- Method: put (obj[, block[, timeout]])

          Put obj into the queue.  If the optional argument 'block' is
          ‘True’ (the default) and 'timeout' is ‘None’ (the default),
          block if necessary until a free slot is available.  If
          'timeout' is a positive number, it blocks at most 'timeout'
          seconds and raises the *note queue.Full: 3369. exception if no
          free slot was available within that time.  Otherwise ('block'
          is ‘False’), put an item on the queue if a free slot is
          immediately available, else raise the ‘queue.Full’ exception
          ('timeout' is ignored in that case).

          Changed in version 3.8: If the queue is closed, *note
          ValueError: 202. is raised instead of *note AssertionError:
          6ac.

      -- Method: put_nowait (obj)

          Equivalent to ‘put(obj, False)’.

      -- Method: get ([block[, timeout]])

          Remove and return an item from the queue.  If optional args
          'block' is ‘True’ (the default) and 'timeout' is ‘None’ (the
          default), block if necessary until an item is available.  If
          'timeout' is a positive number, it blocks at most 'timeout'
          seconds and raises the *note queue.Empty: 3368. exception if
          no item was available within that time.  Otherwise (block is
          ‘False’), return an item if one is immediately available, else
          raise the ‘queue.Empty’ exception ('timeout' is ignored in
          that case).

          Changed in version 3.8: If the queue is closed, *note
          ValueError: 202. is raised instead of *note OSError: 41a.

      -- Method: get_nowait ()

          Equivalent to ‘get(False)’.

     *note multiprocessing.Queue: 192f. has a few additional methods not
     found in *note queue.Queue: 13e1.  These methods are usually
     unnecessary for most code:

      -- Method: close ()

          Close the queue: release internal resources.

          A queue must not be used anymore after it is closed.  For
          example, *note get(): 1bcd, *note put(): 1bcc. and *note
          empty(): 1704. methods must no longer be called.

          The background thread will quit once it has flushed all
          buffered data to the pipe.  This is called automatically when
          the queue is garbage collected.

      -- Method: join_thread ()

          Join the background thread.  This can only be used after *note
          close(): 1930. has been called.  It blocks until the
          background thread exits, ensuring that all data in the buffer
          has been flushed to the pipe.

          By default if a process is not the creator of the queue then
          on exit it will attempt to join the queue’s background thread.
          The process can call *note cancel_join_thread(): 336b. to make
          ‘join_thread()’ do nothing.

      -- Method: cancel_join_thread ()

          Prevent *note join_thread(): 3370. from blocking.  In
          particular, this prevents the background thread from being
          joined automatically when the process exits – see
          ‘join_thread()’.

          A better name for this method might be
          ‘allow_exit_without_flush()’.  It is likely to cause enqueued
          data to be lost, and you almost certainly will not need to use
          it.  It is really only there if you need the current process
          to exit immediately without waiting to flush enqueued data to
          the underlying pipe, and you don’t care about lost data.

          Note: This class’s functionality requires a functioning shared
          semaphore implementation on the host operating system.
          Without one, the functionality in this class will be disabled,
          and attempts to instantiate a ‘Queue’ will result in an *note
          ImportError: 41c.  See bpo-3770(1) for additional information.
          The same holds true for any of the specialized queue types
          listed below.

 -- Class: multiprocessing.SimpleQueue

     It is a simplified *note Queue: 192f. type, very close to a locked
     *note Pipe: 3348.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

      -- Method: close ()

          Close the queue: release internal resources.

          A queue must not be used anymore after it is closed.  For
          example, *note get(): 3371, *note put(): 3372. and *note
          empty(): 1705. methods must no longer be called.

          Added in version 3.9.

      -- Method: empty ()

          Return ‘True’ if the queue is empty, ‘False’ otherwise.

          Always raises an *note OSError: 41a. if the SimpleQueue is
          closed.

      -- Method: get ()

          Remove and return an item from the queue.

      -- Method: put (item)

          Put 'item' into the queue.

 -- Class: multiprocessing.JoinableQueue ([maxsize])

     ‘JoinableQueue’, a *note Queue: 192f. subclass, is a queue which
     additionally has *note task_done(): 3366. and *note join(): 3373.
     methods.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

      -- Method: task_done ()

          Indicate that a formerly enqueued task is complete.  Used by
          queue consumers.  For each *note get(): 1bcd. used to fetch a
          task, a subsequent call to ‘task_done()’ tells the queue that
          the processing on the task is complete.

          If a *note join(): 3365. is currently blocking, it will resume
          when all items have been processed (meaning that a
          ‘task_done()’ call was received for every item that had been
          *note put(): 1bcc. into the queue).

          Raises a *note ValueError: 202. if called more times than
          there were items placed in the queue.

      -- Method: join ()

          Block until all items in the queue have been gotten and
          processed.

          The count of unfinished tasks goes up whenever an item is
          added to the queue.  The count goes down whenever a consumer
          calls *note task_done(): 3366. to indicate that the item was
          retrieved and all work on it is complete.  When the count of
          unfinished tasks drops to zero, *note join(): 3365. unblocks.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3770


File: python.info,  Node: Miscellaneous<3>,  Next: Connection Objects,  Prev: Pipes and Queues,  Up: Reference<3>

5.18.2.12 Miscellaneous
.......................

 -- Function: multiprocessing.active_children ()

     Return list of all live children of the current process.

     Calling this has the side effect of “joining” any processes which
     have already finished.

 -- Function: multiprocessing.cpu_count ()

     Return the number of CPUs in the system.

     This number is not equivalent to the number of CPUs the current
     process can use.  The number of usable CPUs can be obtained with
     *note os.process_cpu_count(): 1c4. (or
     ‘len(os.sched_getaffinity(0))’).

     When the number of CPUs cannot be determined a *note
     NotImplementedError: 228. is raised.

     See also
     ........

     *note os.cpu_count(): 1c5. *note os.process_cpu_count(): 1c4.

     Changed in version 3.13: The return value can also be overridden
     using the *note -X cpu_count: 176. flag or *note PYTHON_CPU_COUNT:
     210. as this is merely a wrapper around the *note os: a1. cpu count
     APIs.

 -- Function: multiprocessing.current_process ()

     Return the *note Process: b75. object corresponding to the current
     process.

     An analogue of *note threading.current_thread(): 309.

 -- Function: multiprocessing.parent_process ()

     Return the *note Process: b75. object corresponding to the parent
     process of the *note current_process(): 3376.  For the main
     process, ‘parent_process’ will be ‘None’.

     Added in version 3.8.

 -- Function: multiprocessing.freeze_support ()

     Add support for when a program which uses ‘multiprocessing’ has
     been frozen to produce an executable.  (Has been tested with
     'py2exe', 'PyInstaller' and 'cx_Freeze'.)

     One needs to call this function straight after the ‘if __name__ ==
     '__main__'’ line of the main module.  For example:

          from multiprocessing import Process, freeze_support

          def f():
              print('hello world!')

          if __name__ == '__main__':
              freeze_support()
              Process(target=f).start()

     If the ‘freeze_support()’ line is omitted then trying to run the
     frozen executable will raise *note RuntimeError: 195.

     Calling ‘freeze_support()’ has no effect when the start method is
     not 'spawn'.  In addition, if the module is being run normally by
     the Python interpreter (the program has not been frozen), then
     ‘freeze_support()’ has no effect.

 -- Function: multiprocessing.get_all_start_methods ()

     Returns a list of the supported start methods, the first of which
     is the default.  The possible start methods are ‘'fork'’, ‘'spawn'’
     and ‘'forkserver'’.  Not all platforms support all methods.  See
     *note Contexts and start methods: 2c8.

     Added in version 3.4.

 -- Function: multiprocessing.get_context (method=None)

     Return a context object which has the same attributes as the
     ‘multiprocessing’ module.

     If 'method' is ‘None’ then the default context is returned.  Note
     that if the global start method has not been set, this will set it
     to the system default See *note Global start method: 3354. for more
     details.  Otherwise 'method' should be ‘'fork'’, ‘'spawn'’,
     ‘'forkserver'’.  *note ValueError: 202. is raised if the specified
     start method is not available.  See *note Contexts and start
     methods: 2c8.

     Added in version 3.4.

 -- Function: multiprocessing.get_start_method (allow_none=False)

     Return the name of start method used for starting processes.

     If the global start method is not set and 'allow_none' is ‘False’,
     the global start method is set to the default, and its name is
     returned.  See *note Global start method: 3354. for more details.

     The return value can be ‘'fork'’, ‘'spawn'’, ‘'forkserver'’ or
     ‘None’.  See *note Contexts and start methods: 2c8.

     Added in version 3.4.

     Changed in version 3.8: On macOS, the 'spawn' start method is now
     the default.  The 'fork' start method should be considered unsafe
     as it can lead to crashes of the subprocess.  See bpo-33725(1).

 -- Function: multiprocessing.set_executable (executable)

     Set the path of the Python interpreter to use when starting a child
     process.  (By default *note sys.executable: 3bb. is used).
     Embedders will probably need to do something like

          set_executable(os.path.join(sys.exec_prefix, 'pythonw.exe'))

     before they can create child processes.

     Changed in version 3.4: Now supported on POSIX when the ‘'spawn'’
     start method is used.

     Changed in version 3.11: Accepts a *note path-like object: 2a0.

 -- Function: multiprocessing.set_forkserver_preload (module_names)

     Set a list of module names for the forkserver main process to
     attempt to import so that their already imported state is inherited
     by forked processes.  Any *note ImportError: 41c. when doing so is
     silently ignored.  This can be used as a performance enhancement to
     avoid repeated work in every process.

     For this to work, it must be called before the forkserver process
     has been launched (before creating a ‘Pool’ or starting a *note
     Process: b75.).

     Only meaningful when using the ‘'forkserver'’ start method.  See
     *note Contexts and start methods: 2c8.

     Added in version 3.4.

 -- Function: multiprocessing.set_start_method (method, force=False)

     Set the method which should be used to start child processes.  The
     'method' argument can be ‘'fork'’, ‘'spawn'’ or ‘'forkserver'’.
     Raises *note RuntimeError: 195. if the start method has already
     been set and 'force' is not ‘True’.  If 'method' is ‘None’ and
     'force' is ‘True’ then the start method is set to ‘None’.  If
     'method' is ‘None’ and 'force' is ‘False’ then the context is set
     to the default context.

     Note that this should be called at most once, and it should be
     protected inside the ‘if __name__ == '__main__'’ clause of the main
     module.

     See *note Contexts and start methods: 2c8.

     Added in version 3.4.

     Note: ‘multiprocessing’ contains no analogues of *note
     threading.active_count(): 30a, *note threading.enumerate(): 1a00,
     *note threading.settrace(): 84e, *note threading.setprofile(): 84f,
     *note threading.Timer: 119d, or *note threading.local: 1650.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=33725


File: python.info,  Node: Connection Objects,  Next: Synchronization primitives,  Prev: Miscellaneous<3>,  Up: Reference<3>

5.18.2.13 Connection Objects
............................

Connection objects allow the sending and receiving of picklable objects
or strings.  They can be thought of as message oriented connected
sockets.

Connection objects are usually created using *note Pipe: 3348. – see
also *note Listeners and Clients: 3379.

 -- Class: multiprocessing.connection.Connection

      -- Method: send (obj)

          Send an object to the other end of the connection which should
          be read using *note recv(): 337b.

          The object must be picklable.  Very large pickles
          (approximately 32 MiB+, though it depends on the OS) may raise
          a *note ValueError: 202. exception.

      -- Method: recv ()

          Return an object sent from the other end of the connection
          using *note send(): 337a.  Blocks until there is something to
          receive.  Raises *note EOFError: 1321. if there is nothing
          left to receive and the other end was closed.

      -- Method: fileno ()

          Return the file descriptor or handle used by the connection.

      -- Method: close ()

          Close the connection.

          This is called automatically when the connection is garbage
          collected.

      -- Method: poll ([timeout])

          Return whether there is any data available to be read.

          If 'timeout' is not specified then it will return immediately.
          If 'timeout' is a number then this specifies the maximum time
          in seconds to block.  If 'timeout' is ‘None’ then an infinite
          timeout is used.

          Note that multiple connection objects may be polled at once by
          using *note multiprocessing.connection.wait(): 1123.

      -- Method: send_bytes (buffer[, offset[, size]])

          Send byte data from a *note bytes-like object: d55. as a
          complete message.

          If 'offset' is given then data is read from that position in
          'buffer'.  If 'size' is given then that many bytes will be
          read from buffer.  Very large buffers (approximately 32 MiB+,
          though it depends on the OS) may raise a *note ValueError:
          202. exception

      -- Method: recv_bytes ([maxlength])

          Return a complete message of byte data sent from the other end
          of the connection as a string.  Blocks until there is
          something to receive.  Raises *note EOFError: 1321. if there
          is nothing left to receive and the other end has closed.

          If 'maxlength' is specified and the message is longer than
          'maxlength' then *note OSError: 41a. is raised and the
          connection will no longer be readable.

          Changed in version 3.3: This function used to raise *note
          IOError: 1090, which is now an alias of *note OSError: 41a.

      -- Method: recv_bytes_into (buffer[, offset])

          Read into 'buffer' a complete message of byte data sent from
          the other end of the connection and return the number of bytes
          in the message.  Blocks until there is something to receive.
          Raises *note EOFError: 1321. if there is nothing left to
          receive and the other end was closed.

          'buffer' must be a writable *note bytes-like object: d55.  If
          'offset' is given then the message will be written into the
          buffer from that position.  Offset must be a non-negative
          integer less than the length of 'buffer' (in bytes).

          If the buffer is too short then a ‘BufferTooShort’ exception
          is raised and the complete message is available as ‘e.args[0]’
          where ‘e’ is the exception instance.

     Changed in version 3.3: Connection objects themselves can now be
     transferred between processes using *note Connection.send(): 337a.
     and *note Connection.recv(): 337b.

     Connection objects also now support the context management protocol
     – see *note Context Manager Types: 2171.  *note __enter__(): 23ff.
     returns the connection object, and *note __exit__(): 2400. calls
     *note close(): 337d.

For example:

     >>> from multiprocessing import Pipe
     >>> a, b = Pipe()
     >>> a.send([1, 'hello', None])
     >>> b.recv()
     [1, 'hello', None]
     >>> b.send_bytes(b'thank you')
     >>> a.recv_bytes()
     b'thank you'
     >>> import array
     >>> arr1 = array.array('i', range(5))
     >>> arr2 = array.array('i', [0] * 10)
     >>> a.send_bytes(arr1)
     >>> count = b.recv_bytes_into(arr2)
     >>> assert count == len(arr1) * arr1.itemsize
     >>> arr2
     array('i', [0, 1, 2, 3, 4, 0, 0, 0, 0, 0])
     Warning: The *note Connection.recv(): 337b. method automatically
     unpickles the data it receives, which can be a security risk unless
     you can trust the process which sent the message.

     Therefore, unless the connection object was produced using ‘Pipe()’
     you should only use the *note recv(): 337b. and *note send(): 337a.
     methods after performing some sort of authentication.  See *note
     Authentication keys: 335d.

     Warning: If a process is killed while it is trying to read or write
     to a pipe then the data in the pipe is likely to become corrupted,
     because it may become impossible to be sure where the message
     boundaries lie.


File: python.info,  Node: Synchronization primitives,  Next: Shared ctypes Objects,  Prev: Connection Objects,  Up: Reference<3>

5.18.2.14 Synchronization primitives
....................................

Generally synchronization primitives are not as necessary in a
multiprocess program as they are in a multithreaded program.  See the
documentation for *note threading: ed. module.

Note that one can also create synchronization primitives by using a
manager object – see *note Managers: 3367.

 -- Class: multiprocessing.Barrier (parties[, action[, timeout]])

     A barrier object: a clone of *note threading.Barrier: 1228.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     Added in version 3.3.

 -- Class: multiprocessing.BoundedSemaphore ([value])

     A bounded semaphore object: a close analog of *note
     threading.BoundedSemaphore: 119b.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     A solitary difference from its close analog exists: its ‘acquire’
     method’s first argument is named 'block', as is consistent with
     *note Lock.acquire(): 3384.

          Note: On macOS, this is indistinguishable from *note
          Semaphore: 334e. because ‘sem_getvalue()’ is not implemented
          on that platform.

 -- Class: multiprocessing.Condition ([lock])

     A condition variable: an alias for *note threading.Condition: 1199.

     If 'lock' is specified then it should be a *note Lock: 16a2. or
     *note RLock: 15c1. object from ‘multiprocessing’.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     Changed in version 3.3: The *note wait_for(): 3326. method was
     added.

 -- Class: multiprocessing.Event

     A clone of *note threading.Event: 119c.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

 -- Class: multiprocessing.Lock

     A non-recursive lock object: a close analog of *note
     threading.Lock: 178a.  Once a process or thread has acquired a
     lock, subsequent attempts to acquire it from any process or thread
     will block until it is released; any process or thread may release
     it.  The concepts and behaviors of ‘threading.Lock’ as it applies
     to threads are replicated here in *note multiprocessing.Lock: 16a2.
     as it applies to either processes or threads, except as noted.

     Note that ‘Lock’ is actually a factory function which returns an
     instance of ‘multiprocessing.synchronize.Lock’ initialized with a
     default context.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     ‘Lock’ supports the *note context manager: 5d7. protocol and thus
     may be used in *note with: 5d5. statements.

      -- Method: acquire (block=True, timeout=None)

          Acquire a lock, blocking or non-blocking.

          With the 'block' argument set to ‘True’ (the default), the
          method call will block until the lock is in an unlocked state,
          then set it to locked and return ‘True’.  Note that the name
          of this first argument differs from that in *note
          threading.Lock.acquire(): 69b.

          With the 'block' argument set to ‘False’, the method call does
          not block.  If the lock is currently in a locked state, return
          ‘False’; otherwise set the lock to a locked state and return
          ‘True’.

          When invoked with a positive, floating-point value for
          'timeout', block for at most the number of seconds specified
          by 'timeout' as long as the lock can not be acquired.
          Invocations with a negative value for 'timeout' are equivalent
          to a 'timeout' of zero.  Invocations with a 'timeout' value of
          ‘None’ (the default) set the timeout period to infinite.  Note
          that the treatment of negative or ‘None’ values for 'timeout'
          differs from the implemented behavior in *note
          threading.Lock.acquire(): 69b.  The 'timeout' argument has no
          practical implications if the 'block' argument is set to
          ‘False’ and is thus ignored.  Returns ‘True’ if the lock has
          been acquired or ‘False’ if the timeout period has elapsed.

      -- Method: release ()

          Release a lock.  This can be called from any process or
          thread, not only the process or thread which originally
          acquired the lock.

          Behavior is the same as in *note threading.Lock.release():
          130a. except that when invoked on an unlocked lock, a *note
          ValueError: 202. is raised.

 -- Class: multiprocessing.RLock

     A recursive lock object: a close analog of *note threading.RLock:
     2de.  A recursive lock must be released by the process or thread
     that acquired it.  Once a process or thread has acquired a
     recursive lock, the same process or thread may acquire it again
     without blocking; that process or thread must release it once for
     each time it has been acquired.

     Note that ‘RLock’ is actually a factory function which returns an
     instance of ‘multiprocessing.synchronize.RLock’ initialized with a
     default context.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     ‘RLock’ supports the *note context manager: 5d7. protocol and thus
     may be used in *note with: 5d5. statements.

      -- Method: acquire (block=True, timeout=None)

          Acquire a lock, blocking or non-blocking.

          When invoked with the 'block' argument set to ‘True’, block
          until the lock is in an unlocked state (not owned by any
          process or thread) unless the lock is already owned by the
          current process or thread.  The current process or thread then
          takes ownership of the lock (if it does not already have
          ownership) and the recursion level inside the lock increments
          by one, resulting in a return value of ‘True’.  Note that
          there are several differences in this first argument’s
          behavior compared to the implementation of *note
          threading.RLock.acquire(): eaf, starting with the name of the
          argument itself.

          When invoked with the 'block' argument set to ‘False’, do not
          block.  If the lock has already been acquired (and thus is
          owned) by another process or thread, the current process or
          thread does not take ownership and the recursion level within
          the lock is not changed, resulting in a return value of
          ‘False’.  If the lock is in an unlocked state, the current
          process or thread takes ownership and the recursion level is
          incremented, resulting in a return value of ‘True’.

          Use and behaviors of the 'timeout' argument are the same as in
          *note Lock.acquire(): 3384.  Note that some of these behaviors
          of 'timeout' differ from the implemented behaviors in *note
          threading.RLock.acquire(): eaf.

      -- Method: release ()

          Release a lock, decrementing the recursion level.  If after
          the decrement the recursion level is zero, reset the lock to
          unlocked (not owned by any process or thread) and if any other
          processes or threads are blocked waiting for the lock to
          become unlocked, allow exactly one of them to proceed.  If
          after the decrement the recursion level is still nonzero, the
          lock remains locked and owned by the calling process or
          thread.

          Only call this method when the calling process or thread owns
          the lock.  An *note AssertionError: 6ac. is raised if this
          method is called by a process or thread other than the owner
          or if the lock is in an unlocked (unowned) state.  Note that
          the type of exception raised in this situation differs from
          the implemented behavior in *note threading.RLock.release():
          3321.

 -- Class: multiprocessing.Semaphore ([value])

     A semaphore object: a close analog of *note threading.Semaphore:
     119a.

     Instantiating this class may set the global start method.  See
     *note Global start method: 3354. for more details.

     A solitary difference from its close analog exists: its ‘acquire’
     method’s first argument is named 'block', as is consistent with
     *note Lock.acquire(): 3384.

     Note: On macOS, ‘sem_timedwait’ is unsupported, so calling
     ‘acquire()’ with a timeout will emulate that function’s behavior
     using a sleeping loop.

     Note: Some of this package’s functionality requires a functioning
     shared semaphore implementation on the host operating system.
     Without one, the ‘multiprocessing.synchronize’ module will be
     disabled, and attempts to import it will result in an *note
     ImportError: 41c.  See bpo-3770(1) for additional information.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=3770


File: python.info,  Node: Shared ctypes Objects,  Next: Managers,  Prev: Synchronization primitives,  Up: Reference<3>

5.18.2.15 Shared ‘ctypes’ Objects
.................................

It is possible to create shared objects using shared memory which can be
inherited by child processes.

 -- Function: multiprocessing.Value (typecode_or_type, *args, lock=True)

     Return a *note ctypes: 2a. object allocated from shared memory.  By
     default the return value is actually a synchronized wrapper for the
     object.  The object itself can be accessed via the 'value'
     attribute of a *note Value: 334b.

     'typecode_or_type' determines the type of the returned object: it
     is either a ctypes type or a one character typecode of the kind
     used by the *note array: 7. module.  '*args' is passed on to the
     constructor for the type.

     If 'lock' is ‘True’ (the default) then a new recursive lock object
     is created to synchronize access to the value.  If 'lock' is a
     *note Lock: 16a2. or *note RLock: 15c1. object then that will be
     used to synchronize access to the value.  If 'lock' is ‘False’ then
     access to the returned object will not be automatically protected
     by a lock, so it will not necessarily be “process-safe”.

     Operations like ‘+=’ which involve a read and write are not atomic.
     So if, for instance, you want to atomically increment a shared
     value it is insufficient to just do

          counter.value += 1

     Assuming the associated lock is recursive (which it is by default)
     you can instead do

          with counter.get_lock():
              counter.value += 1

     Note that 'lock' is a keyword-only argument.

 -- Function: multiprocessing.Array (typecode_or_type,
          size_or_initializer, *, lock=True)

     Return a ctypes array allocated from shared memory.  By default the
     return value is actually a synchronized wrapper for the array.

     'typecode_or_type' determines the type of the elements of the
     returned array: it is either a *note ctypes type: 2fd6. or a one
     character typecode of the kind used by the *note array: 7. module
     with the exception of ‘'w'’, which is not supported.  In addition,
     the ‘'c'’ typecode is an alias for *note ctypes.c_char: 2fd9.  If
     'size_or_initializer' is an integer, then it determines the length
     of the array, and the array will be initially zeroed.  Otherwise,
     'size_or_initializer' is a sequence which is used to initialize the
     array and whose length determines the length of the array.

     If 'lock' is ‘True’ (the default) then a new lock object is created
     to synchronize access to the value.  If 'lock' is a *note Lock:
     16a2. or *note RLock: 15c1. object then that will be used to
     synchronize access to the value.  If 'lock' is ‘False’ then access
     to the returned object will not be automatically protected by a
     lock, so it will not necessarily be “process-safe”.

     Note that 'lock' is a keyword only argument.

     Note that an array of *note ctypes.c_char: 2fd9. has 'value' and
     'raw' attributes which allow one to use it to store and retrieve
     strings.

* Menu:

* The multiprocessing.sharedctypes module: The multiprocessing sharedctypes module.


File: python.info,  Node: The multiprocessing sharedctypes module,  Up: Shared ctypes Objects

5.18.2.16 The ‘multiprocessing.sharedctypes’ module
...................................................

The ‘multiprocessing.sharedctypes’ module provides functions for
allocating *note ctypes: 2a. objects from shared memory which can be
inherited by child processes.

     Note: Although it is possible to store a pointer in shared memory
     remember that this will refer to a location in the address space of
     a specific process.  However, the pointer is quite likely to be
     invalid in the context of a second process and trying to
     dereference the pointer from the second process may cause a crash.

 -- Function: multiprocessing.sharedctypes.RawArray (typecode_or_type,
          size_or_initializer)

     Return a ctypes array allocated from shared memory.

     'typecode_or_type' determines the type of the elements of the
     returned array: it is either a ctypes type or a one character
     typecode of the kind used by the *note array: 7. module.  If
     'size_or_initializer' is an integer then it determines the length
     of the array, and the array will be initially zeroed.  Otherwise
     'size_or_initializer' is a sequence which is used to initialize the
     array and whose length determines the length of the array.

     Note that setting and getting an element is potentially non-atomic
     – use *note Array(): 338b. instead to make sure that access is
     automatically synchronized using a lock.

 -- Function: multiprocessing.sharedctypes.RawValue (typecode_or_type,
          *args)

     Return a ctypes object allocated from shared memory.

     'typecode_or_type' determines the type of the returned object: it
     is either a ctypes type or a one character typecode of the kind
     used by the *note array: 7. module.  '*args' is passed on to the
     constructor for the type.

     Note that setting and getting the value is potentially non-atomic –
     use *note Value(): 338d. instead to make sure that access is
     automatically synchronized using a lock.

     Note that an array of *note ctypes.c_char: 2fd9. has ‘value’ and
     ‘raw’ attributes which allow one to use it to store and retrieve
     strings – see documentation for *note ctypes: 2a.

 -- Function: multiprocessing.sharedctypes.Array (typecode_or_type,
          size_or_initializer, *, lock=True, ctx=None)

     The same as *note RawArray(): 338a. except that depending on the
     value of 'lock' a process-safe synchronization wrapper may be
     returned instead of a raw ctypes array.

     If 'lock' is ‘True’ (the default) then a new lock object is created
     to synchronize access to the value.  If 'lock' is a *note Lock:
     16a2. or *note RLock: 15c1. object then that will be used to
     synchronize access to the value.  If 'lock' is ‘False’ then access
     to the returned object will not be automatically protected by a
     lock, so it will not necessarily be “process-safe”.

     'ctx' is a context object, or ‘None’ (use the current context).  If
     ‘None’, calling this may set the global start method.  See *note
     Global start method: 3354. for more details.

     Note that 'lock' and 'ctx' are keyword-only parameters.

 -- Function: multiprocessing.sharedctypes.Value (typecode_or_type,
          *args, lock=True, ctx=None)

     The same as *note RawValue(): 338c. except that depending on the
     value of 'lock' a process-safe synchronization wrapper may be
     returned instead of a raw ctypes object.

     If 'lock' is ‘True’ (the default) then a new lock object is created
     to synchronize access to the value.  If 'lock' is a *note Lock:
     16a2. or *note RLock: 15c1. object then that will be used to
     synchronize access to the value.  If 'lock' is ‘False’ then access
     to the returned object will not be automatically protected by a
     lock, so it will not necessarily be “process-safe”.

     'ctx' is a context object, or ‘None’ (use the current context).  If
     ‘None’, calling this may set the global start method.  See *note
     Global start method: 3354. for more details.

     Note that 'lock' and 'ctx' are keyword-only parameters.

 -- Function: multiprocessing.sharedctypes.copy (obj)

     Return a ctypes object allocated from shared memory which is a copy
     of the ctypes object 'obj'.

 -- Function: multiprocessing.sharedctypes.synchronized (obj, lock=None,
          ctx=None)

     Return a process-safe wrapper object for a ctypes object which uses
     'lock' to synchronize access.  If 'lock' is ‘None’ (the default)
     then a *note multiprocessing.RLock: 15c1. object is created
     automatically.

     'ctx' is a context object, or ‘None’ (use the current context).  If
     ‘None’, calling this may set the global start method.  See *note
     Global start method: 3354. for more details.

     A synchronized wrapper will have two methods in addition to those
     of the object it wraps: ‘get_obj()’ returns the wrapped object and
     ‘get_lock()’ returns the lock object used for synchronization.

     Note that accessing the ctypes object through the wrapper can be a
     lot slower than accessing the raw ctypes object.

     Changed in version 3.5: Synchronized objects support the *note
     context manager: 5d7. protocol.

The table below compares the syntax for creating shared ctypes objects
from shared memory with the normal ctypes syntax.  (In the table
‘MyStruct’ is some subclass of *note ctypes.Structure: 1d4.)

ctypes                   sharedctypes using type        sharedctypes using typecode
                                                        
----------------------------------------------------------------------------------------
                                                        
c_double(2.4)            RawValue(c_double, 2.4)        RawValue(‘d’, 2.4)
                                                        
                                                        
MyStruct(4, 6)           RawValue(MyStruct, 4, 6)
                         
                                                        
(c_short * 7)()          RawArray(c_short, 7)           RawArray(‘h’, 7)
                                                        
                                                        
(c_int * 3)(9, 2, 8)     RawArray(c_int, (9, 2, 8))     RawArray(‘i’, (9, 2, 8))
                                                        

Below is an example where a number of ctypes objects are modified by a
child process:

     from multiprocessing import Process, Lock
     from multiprocessing.sharedctypes import Value, Array
     from ctypes import Structure, c_double

     class Point(Structure):
         _fields_ = [('x', c_double), ('y', c_double)]

     def modify(n, x, s, A):
         n.value **= 2
         x.value **= 2
         s.value = s.value.upper()
         for a in A:
             a.x **= 2
             a.y **= 2

     if __name__ == '__main__':
         lock = Lock()

         n = Value('i', 7)
         x = Value(c_double, 1.0/3.0, lock=False)
         s = Array('c', b'hello world', lock=lock)
         A = Array(Point, [(1.875,-6.25), (-5.75,2.0), (2.375,9.5)], lock=lock)

         p = Process(target=modify, args=(n, x, s, A))
         p.start()
         p.join()

         print(n.value)
         print(x.value)
         print(s.value)
         print([(a.x, a.y) for a in A])

The results printed are

     49
     0.1111111111111111
     HELLO WORLD
     [(3.515625, 39.0625), (33.0625, 4.0), (5.640625, 90.25)]


File: python.info,  Node: Managers,  Next: Proxy Objects,  Prev: Shared ctypes Objects,  Up: Reference<3>

5.18.2.17 Managers
..................

Managers provide a way to create data which can be shared between
different processes, including sharing over a network between processes
running on different machines.  A manager object controls a server
process which manages 'shared objects'.  Other processes can access the
shared objects by using proxies.

 -- Function: multiprocessing.Manager ()

     Returns a started *note SyncManager: 3390. object which can be used
     for sharing objects between processes.  The returned manager object
     corresponds to a spawned child process and has methods which will
     create shared objects and return corresponding proxies.

Manager processes will be shutdown as soon as they are garbage collected
or their parent process exits.  The manager classes are defined in the
*note multiprocessing.managers: 97. module:

 -- Class: multiprocessing.managers.BaseManager (address=None,
          authkey=None, serializer='pickle', ctx=None, *,
          shutdown_timeout=1.0)

     Create a BaseManager object.

     Once created one should call *note start(): 3392. or
     ‘get_server().serve_forever()’ to ensure that the manager object
     refers to a started manager process.

     'address' is the address on which the manager process listens for
     new connections.  If 'address' is ‘None’ then an arbitrary one is
     chosen.

     'authkey' is the authentication key which will be used to check the
     validity of incoming connections to the server process.  If
     'authkey' is ‘None’ then ‘current_process().authkey’ is used.
     Otherwise 'authkey' is used and it must be a byte string.

     'serializer' must be ‘'pickle'’ (use *note pickle: a6.
     serialization) or ‘'xmlrpclib'’ (use *note xmlrpc.client: 12e.
     serialization).

     'ctx' is a context object, or ‘None’ (use the current context).  If
     ‘None’, calling this may set the global start method.  See *note
     Global start method: 3354. for more details.

     'shutdown_timeout' is a timeout in seconds used to wait until the
     process used by the manager completes in the *note shutdown():
     3393. method.  If the shutdown times out, the process is
     terminated.  If terminating the process also times out, the process
     is killed.

     Changed in version 3.11: Added the 'shutdown_timeout' parameter.

      -- Method: start ([initializer[, initargs]])

          Start a subprocess to start the manager.  If 'initializer' is
          not ‘None’ then the subprocess will call
          ‘initializer(*initargs)’ when it starts.

      -- Method: get_server ()

          Returns a ‘Server’ object which represents the actual server
          under the control of the Manager.  The ‘Server’ object
          supports the ‘serve_forever()’ method:

               >>> from multiprocessing.managers import BaseManager
               >>> manager = BaseManager(address=('', 50000), authkey=b'abc')
               >>> server = manager.get_server()
               >>> server.serve_forever()

          ‘Server’ additionally has an *note address: 3395. attribute.

      -- Method: connect ()

          Connect a local manager object to a remote manager process:

               >>> from multiprocessing.managers import BaseManager
               >>> m = BaseManager(address=('127.0.0.1', 50000), authkey=b'abc')
               >>> m.connect()

      -- Method: shutdown ()

          Stop the process used by the manager.  This is only available
          if *note start(): 3392. has been used to start the server
          process.

          This can be called multiple times.

      -- Method: register (typeid[, callable[, proxytype[, exposed[,
               method_to_typeid[, create_method]]]]])

          A classmethod which can be used for registering a type or
          callable with the manager class.

          'typeid' is a “type identifier” which is used to identify a
          particular type of shared object.  This must be a string.

          'callable' is a callable used for creating objects for this
          type identifier.  If a manager instance will be connected to
          the server using the *note connect(): 3396. method, or if the
          'create_method' argument is ‘False’ then this can be left as
          ‘None’.

          'proxytype' is a subclass of *note BaseProxy: 3398. which is
          used to create proxies for shared objects with this 'typeid'.
          If ‘None’ then a proxy class is created automatically.

          'exposed' is used to specify a sequence of method names which
          proxies for this typeid should be allowed to access using
          *note BaseProxy._callmethod(): 3399.  (If 'exposed' is ‘None’
          then ‘proxytype._exposed_’ is used instead if it exists.)  In
          the case where no exposed list is specified, all “public
          methods” of the shared object will be accessible.  (Here a
          “public method” means any attribute which has a *note
          __call__(): 55b. method and whose name does not begin with
          ‘'_'’.)

          'method_to_typeid' is a mapping used to specify the return
          type of those exposed methods which should return a proxy.  It
          maps method names to typeid strings.  (If 'method_to_typeid'
          is ‘None’ then ‘proxytype._method_to_typeid_’ is used instead
          if it exists.)  If a method’s name is not a key of this
          mapping or if the mapping is ‘None’ then the object returned
          by the method will be copied by value.

          'create_method' determines whether a method should be created
          with name 'typeid' which can be used to tell the server
          process to create a new shared object and return a proxy for
          it.  By default it is ‘True’.

     ‘BaseManager’ instances also have one read-only property:

      -- Attribute: address

          The address used by the manager.

     Changed in version 3.3: Manager objects support the context
     management protocol – see *note Context Manager Types: 2171.  *note
     __enter__(): 23ff. starts the server process (if it has not already
     started) and then returns the manager object.  *note __exit__():
     2400. calls *note shutdown(): 3393.

     In previous versions *note __enter__(): 23ff. did not start the
     manager’s server process if it was not already started.

 -- Class: multiprocessing.managers.SyncManager

     A subclass of *note BaseManager: 3391. which can be used for the
     synchronization of processes.  Objects of this type are returned by
     *note multiprocessing.Manager(): ce0.

     Its methods create and return *note Proxy Objects: cdf. for a
     number of commonly used data types to be synchronized across
     processes.  This notably includes shared lists and dictionaries.

      -- Method: Barrier (parties[, action[, timeout]])

          Create a shared *note threading.Barrier: 1228. object and
          return a proxy for it.

          Added in version 3.3.

      -- Method: BoundedSemaphore ([value])

          Create a shared *note threading.BoundedSemaphore: 119b. object
          and return a proxy for it.

      -- Method: Condition ([lock])

          Create a shared *note threading.Condition: 1199. object and
          return a proxy for it.

          If 'lock' is supplied then it should be a proxy for a *note
          threading.Lock: 178a. or *note threading.RLock: 2de. object.

          Changed in version 3.3: The *note wait_for(): 3326. method was
          added.

      -- Method: Event ()

          Create a shared *note threading.Event: 119c. object and return
          a proxy for it.

      -- Method: Lock ()

          Create a shared *note threading.Lock: 178a. object and return
          a proxy for it.

      -- Method: Namespace ()

          Create a shared *note Namespace: 334d. object and return a
          proxy for it.

      -- Method: Queue ([maxsize])

          Create a shared *note queue.Queue: 13e1. object and return a
          proxy for it.

      -- Method: RLock ()

          Create a shared *note threading.RLock: 2de. object and return
          a proxy for it.

      -- Method: Semaphore ([value])

          Create a shared *note threading.Semaphore: 119a. object and
          return a proxy for it.

      -- Method: Array (typecode, sequence)

          Create an array and return a proxy for it.

      -- Method: Value (typecode, value)

          Create an object with a writable ‘value’ attribute and return
          a proxy for it.

      -- Method: dict ()

      -- Method: dict (mapping)

      -- Method: dict (sequence)

          Create a shared *note dict: 256. object and return a proxy for
          it.

      -- Method: list ()

      -- Method: list (sequence)

          Create a shared *note list: 614. object and return a proxy for
          it.

     Changed in version 3.6: Shared objects are capable of being nested.
     For example, a shared container object such as a shared list can
     contain other shared objects which will all be managed and
     synchronized by the ‘SyncManager’.

 -- Class: multiprocessing.managers.Namespace

     A type that can register with *note SyncManager: 3390.

     A namespace object has no public methods, but does have writable
     attributes.  Its representation shows the values of its attributes.

     However, when using a proxy for a namespace object, an attribute
     beginning with ‘'_'’ will be an attribute of the proxy and not an
     attribute of the referent:

          >>> mp_context = multiprocessing.get_context('spawn')
          >>> manager = mp_context.Manager()
          >>> Global = manager.Namespace()
          >>> Global.x = 10
          >>> Global.y = 'hello'
          >>> Global._z = 12.3    # this is an attribute of the proxy
          >>> print(Global)
          Namespace(x=10, y='hello')

* Menu:

* Customized managers::
* Using a remote manager::


File: python.info,  Node: Customized managers,  Next: Using a remote manager,  Up: Managers

5.18.2.18 Customized managers
.............................

To create one’s own manager, one creates a subclass of *note
BaseManager: 3391. and uses the *note register(): 3397. classmethod to
register new types or callables with the manager class.  For example:

     from multiprocessing.managers import BaseManager

     class MathsClass:
         def add(self, x, y):
             return x + y
         def mul(self, x, y):
             return x * y

     class MyManager(BaseManager):
         pass

     MyManager.register('Maths', MathsClass)

     if __name__ == '__main__':
         with MyManager() as manager:
             maths = manager.Maths()
             print(maths.add(4, 3))         # prints 7
             print(maths.mul(7, 8))         # prints 56


File: python.info,  Node: Using a remote manager,  Prev: Customized managers,  Up: Managers

5.18.2.19 Using a remote manager
................................

It is possible to run a manager server on one machine and have clients
use it from other machines (assuming that the firewalls involved allow
it).

Running the following commands creates a server for a single shared
queue which remote clients can access:

     >>> from multiprocessing.managers import BaseManager
     >>> from queue import Queue
     >>> queue = Queue()
     >>> class QueueManager(BaseManager): pass
     >>> QueueManager.register('get_queue', callable=lambda:queue)
     >>> m = QueueManager(address=('', 50000), authkey=b'abracadabra')
     >>> s = m.get_server()
     >>> s.serve_forever()

One client can access the server as follows:

     >>> from multiprocessing.managers import BaseManager
     >>> class QueueManager(BaseManager): pass
     >>> QueueManager.register('get_queue')
     >>> m = QueueManager(address=('foo.bar.org', 50000), authkey=b'abracadabra')
     >>> m.connect()
     >>> queue = m.get_queue()
     >>> queue.put('hello')

Another client can also use it:

     >>> from multiprocessing.managers import BaseManager
     >>> class QueueManager(BaseManager): pass
     >>> QueueManager.register('get_queue')
     >>> m = QueueManager(address=('foo.bar.org', 50000), authkey=b'abracadabra')
     >>> m.connect()
     >>> queue = m.get_queue()
     >>> queue.get()
     'hello'

Local processes can also access that queue, using the code from above on
the client to access it remotely:

     >>> from multiprocessing import Process, Queue
     >>> from multiprocessing.managers import BaseManager
     >>> class Worker(Process):
     ...     def __init__(self, q):
     ...         self.q = q
     ...         super().__init__()
     ...     def run(self):
     ...         self.q.put('local hello')
     ...
     >>> queue = Queue()
     >>> w = Worker(queue)
     >>> w.start()
     >>> class QueueManager(BaseManager): pass
     ...
     >>> QueueManager.register('get_queue', callable=lambda: queue)
     >>> m = QueueManager(address=('', 50000), authkey=b'abracadabra')
     >>> s = m.get_server()
     >>> s.serve_forever()


File: python.info,  Node: Proxy Objects,  Next: Process Pools,  Prev: Managers,  Up: Reference<3>

5.18.2.20 Proxy Objects
.......................

A proxy is an object which 'refers' to a shared object which lives
(presumably) in a different process.  The shared object is said to be
the 'referent' of the proxy.  Multiple proxy objects may have the same
referent.

A proxy object has methods which invoke corresponding methods of its
referent (although not every method of the referent will necessarily be
available through the proxy).  In this way, a proxy can be used just
like its referent can:

     >>> mp_context = multiprocessing.get_context('spawn')
     >>> manager = mp_context.Manager()
     >>> l = manager.list([i*i for i in range(10)])
     >>> print(l)
     [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
     >>> print(repr(l))
     <ListProxy object, typeid 'list' at 0x...>
     >>> l[4]
     16
     >>> l[2:5]
     [4, 9, 16]

Notice that applying *note str(): 44f. to a proxy will return the
representation of the referent, whereas applying *note repr(): 803. will
return the representation of the proxy.

An important feature of proxy objects is that they are picklable so they
can be passed between processes.  As such, a referent can contain *note
Proxy Objects: cdf.  This permits nesting of these managed lists, dicts,
and other *note Proxy Objects: cdf.:

     >>> a = manager.list()
     >>> b = manager.list()
     >>> a.append(b)         # referent of a now contains referent of b
     >>> print(a, b)
     [<ListProxy object, typeid 'list' at ...>] []
     >>> b.append('hello')
     >>> print(a[0], b)
     ['hello'] ['hello']

Similarly, dict and list proxies may be nested inside one another:

     >>> l_outer = manager.list([ manager.dict() for i in range(2) ])
     >>> d_first_inner = l_outer[0]
     >>> d_first_inner['a'] = 1
     >>> d_first_inner['b'] = 2
     >>> l_outer[1]['c'] = 3
     >>> l_outer[1]['z'] = 26
     >>> print(l_outer[0])
     {'a': 1, 'b': 2}
     >>> print(l_outer[1])
     {'c': 3, 'z': 26}

If standard (non-proxy) *note list: 614. or *note dict: 256. objects are
contained in a referent, modifications to those mutable values will not
be propagated through the manager because the proxy has no way of
knowing when the values contained within are modified.  However, storing
a value in a container proxy (which triggers a ‘__setitem__’ on the
proxy object) does propagate through the manager and so to effectively
modify such an item, one could re-assign the modified value to the
container proxy:

     # create a list proxy and append a mutable object (a dictionary)
     lproxy = manager.list()
     lproxy.append({})
     # now mutate the dictionary
     d = lproxy[0]
     d['a'] = 1
     d['b'] = 2
     # at this point, the changes to d are not yet synced, but by
     # updating the dictionary, the proxy is notified of the change
     lproxy[0] = d

This approach is perhaps less convenient than employing nested *note
Proxy Objects: cdf. for most use cases but also demonstrates a level of
control over the synchronization.

     Note: The proxy types in ‘multiprocessing’ do nothing to support
     comparisons by value.  So, for instance, we have:

          >>> manager.list([1,2,3]) == [1,2,3]
          False

     One should just use a copy of the referent instead when making
     comparisons.

 -- Class: multiprocessing.managers.BaseProxy

     Proxy objects are instances of subclasses of ‘BaseProxy’.

      -- Method: _callmethod (methodname[, args[, kwds]])

          Call and return the result of a method of the proxy’s
          referent.

          If ‘proxy’ is a proxy whose referent is ‘obj’ then the
          expression

               proxy._callmethod(methodname, args, kwds)

          will evaluate the expression

               getattr(obj, methodname)(*args, **kwds)

          in the manager’s process.

          The returned value will be a copy of the result of the call or
          a proxy to a new shared object – see documentation for the
          'method_to_typeid' argument of *note BaseManager.register():
          3397.

          If an exception is raised by the call, then is re-raised by
          ‘_callmethod()’.  If some other exception is raised in the
          manager’s process then this is converted into a ‘RemoteError’
          exception and is raised by ‘_callmethod()’.

          Note in particular that an exception will be raised if
          'methodname' has not been 'exposed'.

          An example of the usage of ‘_callmethod()’:

               >>> l = manager.list(range(10))
               >>> l._callmethod('__len__')
               10
               >>> l._callmethod('__getitem__', (slice(2, 7),)) # equivalent to l[2:7]
               [2, 3, 4, 5, 6]
               >>> l._callmethod('__getitem__', (20,))          # equivalent to l[20]
               Traceback (most recent call last):
               ...
               IndexError: list index out of range

      -- Method: _getvalue ()

          Return a copy of the referent.

          If the referent is unpicklable then this will raise an
          exception.

      -- Method: __repr__ ()

          Return a representation of the proxy object.

      -- Method: __str__ ()

          Return the representation of the referent.

* Menu:

* Cleanup: Cleanup<2>.


File: python.info,  Node: Cleanup<2>,  Up: Proxy Objects

5.18.2.21 Cleanup
.................

A proxy object uses a weakref callback so that when it gets garbage
collected it deregisters itself from the manager which owns its
referent.

A shared object gets deleted from the manager process when there are no
longer any proxies referring to it.


File: python.info,  Node: Process Pools,  Next: Listeners and Clients,  Prev: Proxy Objects,  Up: Reference<3>

5.18.2.22 Process Pools
.......................

One can create a pool of processes which will carry out tasks submitted
to it with the *note Pool: fa4. class.

 -- Class: multiprocessing.pool.Pool ([processes[, initializer[,
          initargs[, maxtasksperchild[, context]]]]])

     A process pool object which controls a pool of worker processes to
     which jobs can be submitted.  It supports asynchronous results with
     timeouts and callbacks and has a parallel map implementation.

     'processes' is the number of worker processes to use.  If
     'processes' is ‘None’ then the number returned by *note
     os.process_cpu_count(): 1c4. is used.

     If 'initializer' is not ‘None’ then each worker process will call
     ‘initializer(*initargs)’ when it starts.

     'maxtasksperchild' is the number of tasks a worker process can
     complete before it will exit and be replaced with a fresh worker
     process, to enable unused resources to be freed.  The default
     'maxtasksperchild' is ‘None’, which means worker processes will
     live as long as the pool.

     'context' can be used to specify the context used for starting the
     worker processes.  Usually a pool is created using the function
     ‘multiprocessing.Pool()’ or the *note Pool(): fa4. method of a
     context object.  In both cases 'context' is set appropriately.  If
     ‘None’, calling this function will have the side effect of setting
     the current global start method if it has not been set already.
     See the ‘get_context()’ function.

     Note that the methods of the pool object should only be called by
     the process which created the pool.

          Warning: *note multiprocessing.pool: 98. objects have internal
          resources that need to be properly managed (like any other
          resource) by using the pool as a context manager or by calling
          *note close(): 33ab. and *note terminate(): 33ac. manually.
          Failure to do this can lead to the process hanging on
          finalization.

          Note that it is 'not correct' to rely on the garbage collector
          to destroy the pool as CPython does not assure that the
          finalizer of the pool will be called (see *note
          object.__del__(): 1038. for more information).

     Changed in version 3.2: Added the 'maxtasksperchild' parameter.

     Changed in version 3.4: Added the 'context' parameter.

     Changed in version 3.13: 'processes' uses *note
     os.process_cpu_count(): 1c4. by default, instead of *note
     os.cpu_count(): 1c5.

          Note: Worker processes within a ‘Pool’ typically live for the
          complete duration of the Pool’s work queue.  A frequent
          pattern found in other systems (such as Apache, mod_wsgi, etc)
          to free resources held by workers is to allow a worker within
          a pool to complete only a set amount of work before exiting,
          being cleaned up and a new process spawned to replace the old
          one.  The 'maxtasksperchild' argument to the ‘Pool’ exposes
          this ability to the end user.

      -- Method: apply (func[, args[, kwds]])

          Call 'func' with arguments 'args' and keyword arguments
          'kwds'.  It blocks until the result is ready.  Given this
          blocks, *note apply_async(): 13e3. is better suited for
          performing work in parallel.  Additionally, 'func' is only
          executed in one of the workers of the pool.

      -- Method: apply_async (func[, args[, kwds[, callback[,
               error_callback]]]])

          A variant of the *note apply(): 13e2. method which returns a
          *note AsyncResult: 33ad. object.

          If 'callback' is specified then it should be a callable which
          accepts a single argument.  When the result becomes ready
          'callback' is applied to it, that is unless the call failed,
          in which case the 'error_callback' is applied instead.

          If 'error_callback' is specified then it should be a callable
          which accepts a single argument.  If the target function
          fails, then the 'error_callback' is called with the exception
          instance.

          Callbacks should complete immediately since otherwise the
          thread which handles the results will get blocked.

      -- Method: map (func, iterable[, chunksize])

          A parallel equivalent of the *note map(): 86a. built-in
          function (it supports only one 'iterable' argument though, for
          multiple iterables see *note starmap(): 1126.).  It blocks
          until the result is ready.

          This method chops the iterable into a number of chunks which
          it submits to the process pool as separate tasks.  The
          (approximate) size of these chunks can be specified by setting
          'chunksize' to a positive integer.

          Note that it may cause high memory usage for very long
          iterables.  Consider using *note imap(): 33ae. or *note
          imap_unordered(): 33af. with explicit 'chunksize' option for
          better efficiency.

      -- Method: map_async (func, iterable[, chunksize[, callback[,
               error_callback]]])

          A variant of the *note map(): 1129. method which returns a
          *note AsyncResult: 33ad. object.

          If 'callback' is specified then it should be a callable which
          accepts a single argument.  When the result becomes ready
          'callback' is applied to it, that is unless the call failed,
          in which case the 'error_callback' is applied instead.

          If 'error_callback' is specified then it should be a callable
          which accepts a single argument.  If the target function
          fails, then the 'error_callback' is called with the exception
          instance.

          Callbacks should complete immediately since otherwise the
          thread which handles the results will get blocked.

      -- Method: imap (func, iterable[, chunksize])

          A lazier version of *note map(): 1129.

          The 'chunksize' argument is the same as the one used by the
          *note map(): 1129. method.  For very long iterables using a
          large value for 'chunksize' can make the job complete 'much'
          faster than using the default value of ‘1’.

          Also if 'chunksize' is ‘1’ then the ‘next()’ method of the
          iterator returned by the ‘imap()’ method has an optional
          'timeout' parameter: ‘next(timeout)’ will raise *note
          multiprocessing.TimeoutError: 3361. if the result cannot be
          returned within 'timeout' seconds.

      -- Method: imap_unordered (func, iterable[, chunksize])

          The same as *note imap(): 33ae. except that the ordering of
          the results from the returned iterator should be considered
          arbitrary.  (Only when there is only one worker process is the
          order guaranteed to be “correct”.)

      -- Method: starmap (func, iterable[, chunksize])

          Like *note map(): 1129. except that the elements of the
          'iterable' are expected to be iterables that are unpacked as
          arguments.

          Hence an 'iterable' of ‘[(1,2), (3, 4)]’ results in
          ‘[func(1,2), func(3,4)]’.

          Added in version 3.3.

      -- Method: starmap_async (func, iterable[, chunksize[, callback[,
               error_callback]]])

          A combination of *note starmap(): 1126. and *note map_async():
          112a. that iterates over 'iterable' of iterables and calls
          'func' with the iterables unpacked.  Returns a result object.

          Added in version 3.3.

      -- Method: close ()

          Prevents any more tasks from being submitted to the pool.
          Once all the tasks have been completed the worker processes
          will exit.

      -- Method: terminate ()

          Stops the worker processes immediately without completing
          outstanding work.  When the pool object is garbage collected
          ‘terminate()’ will be called immediately.

      -- Method: join ()

          Wait for the worker processes to exit.  One must call *note
          close(): 33ab. or *note terminate(): 33ac. before using
          ‘join()’.

     Changed in version 3.3: Pool objects now support the context
     management protocol – see *note Context Manager Types: 2171.  *note
     __enter__(): 23ff. returns the pool object, and *note __exit__():
     2400. calls *note terminate(): 33ac.

 -- Class: multiprocessing.pool.AsyncResult

     The class of the result returned by *note Pool.apply_async(): 13e3.
     and *note Pool.map_async(): 112a.

      -- Method: get ([timeout])

          Return the result when it arrives.  If 'timeout' is not ‘None’
          and the result does not arrive within 'timeout' seconds then
          *note multiprocessing.TimeoutError: 3361. is raised.  If the
          remote call raised an exception then that exception will be
          reraised by ‘get()’.

      -- Method: wait ([timeout])

          Wait until the result is available or until 'timeout' seconds
          pass.

      -- Method: ready ()

          Return whether the call has completed.

      -- Method: successful ()

          Return whether the call completed without raising an
          exception.  Will raise *note ValueError: 202. if the result is
          not ready.

          Changed in version 3.7: If the result is not ready, *note
          ValueError: 202. is raised instead of *note AssertionError:
          6ac.

The following example demonstrates the use of a pool:

     from multiprocessing import Pool
     import time

     def f(x):
         return x*x

     if __name__ == '__main__':
         with Pool(processes=4) as pool:         # start 4 worker processes
             result = pool.apply_async(f, (10,)) # evaluate "f(10)" asynchronously in a single process
             print(result.get(timeout=1))        # prints "100" unless your computer is *very* slow

             print(pool.map(f, range(10)))       # prints "[0, 1, 4,..., 81]"

             it = pool.imap(f, range(10))
             print(next(it))                     # prints "0"
             print(next(it))                     # prints "1"
             print(it.next(timeout=1))           # prints "4" unless your computer is *very* slow

             result = pool.apply_async(time.sleep, (10,))
             print(result.get(timeout=1))        # raises multiprocessing.TimeoutError


File: python.info,  Node: Listeners and Clients,  Next: Authentication keys,  Prev: Process Pools,  Up: Reference<3>

5.18.2.23 Listeners and Clients
...............................

Usually message passing between processes is done using queues or by
using *note Connection: 1124. objects returned by *note Pipe(): 3348.

However, the ‘multiprocessing.connection’ module allows some extra
flexibility.  It basically gives a high level message oriented API for
dealing with sockets or Windows named pipes.  It also has support for
'digest authentication' using the *note hmac: 6a. module, and for
polling multiple connections at the same time.

 -- Function: multiprocessing.connection.deliver_challenge (connection,
          authkey)

     Send a randomly generated message to the other end of the
     connection and wait for a reply.

     If the reply matches the digest of the message using 'authkey' as
     the key then a welcome message is sent to the other end of the
     connection.  Otherwise *note AuthenticationError: 3360. is raised.

 -- Function: multiprocessing.connection.answer_challenge (connection,
          authkey)

     Receive a message, calculate the digest of the message using
     'authkey' as the key, and then send the digest back.

     If a welcome message is not received, then *note
     AuthenticationError: 3360. is raised.

 -- Function: multiprocessing.connection.Client (address[, family[,
          authkey]])

     Attempt to set up a connection to the listener which is using
     address 'address', returning a *note Connection: 1124.

     The type of the connection is determined by 'family' argument, but
     this can generally be omitted since it can usually be inferred from
     the format of 'address'.  (See *note Address Formats: 33b9.)

     If 'authkey' is given and not ‘None’, it should be a byte string
     and will be used as the secret key for an HMAC-based authentication
     challenge.  No authentication is done if 'authkey' is ‘None’.
     *note AuthenticationError: 3360. is raised if authentication fails.
     See *note Authentication keys: 335d.

 -- Class: multiprocessing.connection.Listener ([address[, family[,
          backlog[, authkey]]]])

     A wrapper for a bound socket or Windows named pipe which is
     ‘listening’ for connections.

     'address' is the address to be used by the bound socket or named
     pipe of the listener object.

          Note: If an address of ‘0.0.0.0’ is used, the address will not
          be a connectable end point on Windows.  If you require a
          connectable end-point, you should use ‘127.0.0.1’.

     'family' is the type of socket (or named pipe) to use.  This can be
     one of the strings ‘'AF_INET'’ (for a TCP socket), ‘'AF_UNIX'’ (for
     a Unix domain socket) or ‘'AF_PIPE'’ (for a Windows named pipe).
     Of these only the first is guaranteed to be available.  If 'family'
     is ‘None’ then the family is inferred from the format of 'address'.
     If 'address' is also ‘None’ then a default is chosen.  This default
     is the family which is assumed to be the fastest available.  See
     *note Address Formats: 33b9.  Note that if 'family' is ‘'AF_UNIX'’
     and address is ‘None’ then the socket will be created in a private
     temporary directory created using *note tempfile.mkstemp(): 2a1f.

     If the listener object uses a socket then 'backlog' (1 by default)
     is passed to the *note listen(): e92. method of the socket once it
     has been bound.

     If 'authkey' is given and not ‘None’, it should be a byte string
     and will be used as the secret key for an HMAC-based authentication
     challenge.  No authentication is done if 'authkey' is ‘None’.
     *note AuthenticationError: 3360. is raised if authentication fails.
     See *note Authentication keys: 335d.

      -- Method: accept ()

          Accept a connection on the bound socket or named pipe of the
          listener object and return a *note Connection: 1124. object.
          If authentication is attempted and fails, then *note
          AuthenticationError: 3360. is raised.

      -- Method: close ()

          Close the bound socket or named pipe of the listener object.
          This is called automatically when the listener is garbage
          collected.  However it is advisable to call it explicitly.

     Listener objects have the following read-only properties:

      -- Attribute: address

          The address which is being used by the Listener object.

      -- Attribute: last_accepted

          The address from which the last accepted connection came.  If
          this is unavailable then it is ‘None’.

     Changed in version 3.3: Listener objects now support the context
     management protocol – see *note Context Manager Types: 2171.  *note
     __enter__(): 23ff. returns the listener object, and *note
     __exit__(): 2400. calls *note close(): 33ba.

 -- Function: multiprocessing.connection.wait (object_list,
          timeout=None)

     Wait till an object in 'object_list' is ready.  Returns the list of
     those objects in 'object_list' which are ready.  If 'timeout' is a
     float then the call blocks for at most that many seconds.  If
     'timeout' is ‘None’ then it will block for an unlimited period.  A
     negative timeout is equivalent to a zero timeout.

     For both POSIX and Windows, an object can appear in 'object_list'
     if it is

        * a readable *note Connection: 1124. object;

        * a connected and readable *note socket.socket: dcf. object; or

        * the *note sentinel: 1125. attribute of a *note Process: b75.
          object.

     A connection or socket object is ready when there is data available
     to be read from it, or the other end has been closed.

     'POSIX': ‘wait(object_list, timeout)’ almost equivalent
     ‘select.select(object_list, [], [], timeout)’.  The difference is
     that, if *note select.select(): dce. is interrupted by a signal, it
     can raise *note OSError: 41a. with an error number of ‘EINTR’,
     whereas ‘wait()’ will not.

     'Windows': An item in 'object_list' must either be an integer
     handle which is waitable (according to the definition used by the
     documentation of the Win32 function ‘WaitForMultipleObjects()’) or
     it can be an object with a *note fileno(): 15f5. method which
     returns a socket handle or pipe handle.  (Note that pipe handles
     and socket handles are 'not' waitable handles.)

     Added in version 3.3.

'Examples'

The following server code creates a listener which uses ‘'secret
password'’ as an authentication key.  It then waits for a connection and
sends some data to the client:

     from multiprocessing.connection import Listener
     from array import array

     address = ('localhost', 6000)     # family is deduced to be 'AF_INET'

     with Listener(address, authkey=b'secret password') as listener:
         with listener.accept() as conn:
             print('connection accepted from', listener.last_accepted)

             conn.send([2.25, None, 'junk', float])

             conn.send_bytes(b'hello')

             conn.send_bytes(array('i', [42, 1729]))

The following code connects to the server and receives some data from
the server:

     from multiprocessing.connection import Client
     from array import array

     address = ('localhost', 6000)

     with Client(address, authkey=b'secret password') as conn:
         print(conn.recv())                  # => [2.25, None, 'junk', float]

         print(conn.recv_bytes())            # => 'hello'

         arr = array('i', [0, 0, 0, 0, 0])
         print(conn.recv_bytes_into(arr))    # => 8
         print(arr)                          # => array('i', [42, 1729, 0, 0, 0])

The following code uses *note wait(): 1123. to wait for messages from
multiple processes at once:

     from multiprocessing import Process, Pipe, current_process
     from multiprocessing.connection import wait

     def foo(w):
         for i in range(10):
             w.send((i, current_process().name))
         w.close()

     if __name__ == '__main__':
         readers = []

         for i in range(4):
             r, w = Pipe(duplex=False)
             readers.append(r)
             p = Process(target=foo, args=(w,))
             p.start()
             # We close the writable end of the pipe now to be sure that
             # p is the only process which owns a handle for it.  This
             # ensures that when p closes its handle for the writable end,
             # wait() will promptly report the readable end as being ready.
             w.close()

         while readers:
             for r in wait(readers):
                 try:
                     msg = r.recv()
                 except EOFError:
                     readers.remove(r)
                 else:
                     print(msg)

* Menu:

* Address Formats::


File: python.info,  Node: Address Formats,  Up: Listeners and Clients

5.18.2.24 Address Formats
.........................

   * An ‘'AF_INET'’ address is a tuple of the form ‘(hostname, port)’
     where 'hostname' is a string and 'port' is an integer.

   * An ‘'AF_UNIX'’ address is a string representing a filename on the
     filesystem.

   * An ‘'AF_PIPE'’ address is a string of the form
     ‘r'\\.\pipe\PIPENAME'’.  To use *note Client(): 33b8. to connect to
     a named pipe on a remote computer called 'ServerName' one should
     use an address of the form ‘r'\\SERVERNAME\pipe\PIPENAME'’ instead.

Note that any string beginning with two backslashes is assumed by
default to be an ‘'AF_PIPE'’ address rather than an ‘'AF_UNIX'’ address.


File: python.info,  Node: Authentication keys,  Next: Logging<2>,  Prev: Listeners and Clients,  Up: Reference<3>

5.18.2.25 Authentication keys
.............................

When one uses *note Connection.recv: 337b, the data received is
automatically unpickled.  Unfortunately unpickling data from an
untrusted source is a security risk.  Therefore *note Listener: 17bb.
and *note Client(): 33b8. use the *note hmac: 6a. module to provide
digest authentication.

An authentication key is a byte string which can be thought of as a
password: once a connection is established both ends will demand proof
that the other knows the authentication key.  (Demonstrating that both
ends are using the same key does 'not' involve sending the key over the
connection.)

If authentication is requested but no authentication key is specified
then the return value of ‘current_process().authkey’ is used (see *note
Process: b75.).  This value will be automatically inherited by any
‘Process’ object that the current process creates.  This means that (by
default) all processes of a multi-process program will share a single
authentication key which can be used when setting up connections between
themselves.

Suitable authentication keys can also be generated by using *note
os.urandom(): 526.


File: python.info,  Node: Logging<2>,  Next: The multiprocessing dummy module,  Prev: Authentication keys,  Up: Reference<3>

5.18.2.26 Logging
.................

Some support for logging is available.  Note, however, that the *note
logging: 87. package does not use process shared locks so it is possible
(depending on the handler type) for messages from different processes to
get mixed up.

 -- Function: multiprocessing.get_logger ()

     Returns the logger used by ‘multiprocessing’.  If necessary, a new
     one will be created.

     When first created the logger has level *note logging.NOTSET: 2e56.
     and no default handler.  Messages sent to this logger will not by
     default propagate to the root logger.

     Note that on Windows child processes will only inherit the level of
     the parent process’s logger – any other customization of the logger
     will not be inherited.

 -- Function: multiprocessing.log_to_stderr (level=None)

     This function performs a call to *note get_logger(): 2f1d. but in
     addition to returning the logger created by get_logger, it adds a
     handler which sends output to *note sys.stderr: 943. using format
     ‘'[%(levelname)s/%(processName)s] %(message)s'’.  You can modify
     ‘levelname’ of the logger by passing a ‘level’ argument.

Below is an example session with logging turned on:

     >>> import multiprocessing, logging
     >>> logger = multiprocessing.log_to_stderr()
     >>> logger.setLevel(logging.INFO)
     >>> logger.warning('doomed')
     [WARNING/MainProcess] doomed
     >>> m = multiprocessing.Manager()
     [INFO/SyncManager-...] child process calling self.run()
     [INFO/SyncManager-...] created temp directory /.../pymp-...
     [INFO/SyncManager-...] manager serving at '/.../listener-...'
     >>> del m
     [INFO/MainProcess] sending shutdown message to manager
     [INFO/SyncManager-...] manager exiting with exitcode 0

For a full table of logging levels, see the *note logging: 87. module.


File: python.info,  Node: The multiprocessing dummy module,  Prev: Logging<2>,  Up: Reference<3>

5.18.2.27 The ‘multiprocessing.dummy’ module
............................................

‘multiprocessing.dummy’ replicates the API of ‘multiprocessing’ but is
no more than a wrapper around the *note threading: ed. module.

In particular, the ‘Pool’ function provided by ‘multiprocessing.dummy’
returns an instance of *note ThreadPool: 1a7a, which is a subclass of
*note Pool: fa4. that supports all the same method calls but uses a pool
of worker threads rather than worker processes.

 -- Class: multiprocessing.pool.ThreadPool ([processes[, initializer[,
          initargs]]])

     A thread pool object which controls a pool of worker threads to
     which jobs can be submitted.  ‘ThreadPool’ instances are fully
     interface compatible with *note Pool: fa4. instances, and their
     resources must also be properly managed, either by using the pool
     as a context manager or by calling *note close(): 33ab. and *note
     terminate(): 33ac. manually.

     'processes' is the number of worker threads to use.  If 'processes'
     is ‘None’ then the number returned by *note os.process_cpu_count():
     1c4. is used.

     If 'initializer' is not ‘None’ then each worker process will call
     ‘initializer(*initargs)’ when it starts.

     Unlike *note Pool: fa4, 'maxtasksperchild' and 'context' cannot be
     provided.

          Note: A ‘ThreadPool’ shares the same interface as *note Pool:
          fa4, which is designed around a pool of processes and predates
          the introduction of the *note concurrent.futures: 21. module.
          As such, it inherits some operations that don’t make sense for
          a pool backed by threads, and it has its own type for
          representing the status of asynchronous jobs, *note
          AsyncResult: 33ad, that is not understood by any other
          libraries.

          Users should generally prefer to use *note
          concurrent.futures.ThreadPoolExecutor: 745, which has a
          simpler interface that was designed around threads from the
          start, and which returns *note concurrent.futures.Future:
          11f6. instances that are compatible with many other libraries,
          including *note asyncio: a.


File: python.info,  Node: Programming guidelines,  Next: Examples<14>,  Prev: Reference<3>,  Up: multiprocessing — Process-based parallelism

5.18.2.28 Programming guidelines
................................

There are certain guidelines and idioms which should be adhered to when
using ‘multiprocessing’.

* Menu:

* All start methods::
* The spawn and forkserver start methods::


File: python.info,  Node: All start methods,  Next: The spawn and forkserver start methods,  Up: Programming guidelines

5.18.2.29 All start methods
...........................

The following applies to all start methods.

Avoid shared state

     As far as possible one should try to avoid shifting large amounts
     of data between processes.

     It is probably best to stick to using queues or pipes for
     communication between processes rather than using the lower level
     synchronization primitives.

Picklability

     Ensure that the arguments to the methods of proxies are picklable.

Thread safety of proxies

     Do not use a proxy object from more than one thread unless you
     protect it with a lock.

     (There is never a problem with different processes using the 'same'
     proxy.)

Joining zombie processes

     On POSIX when a process finishes but has not been joined it becomes
     a zombie.  There should never be very many because each time a new
     process starts (or *note active_children(): 3375. is called) all
     completed processes which have not yet been joined will be joined.
     Also calling a finished process’s *note Process.is_alive: 13df.
     will join the process.  Even so it is probably good practice to
     explicitly join all the processes that you start.

Better to inherit than pickle/unpickle

     When using the 'spawn' or 'forkserver' start methods many types
     from ‘multiprocessing’ need to be picklable so that child processes
     can use them.  However, one should generally avoid sending shared
     objects to other processes using pipes or queues.  Instead you
     should arrange the program so that a process which needs access to
     a shared resource created elsewhere can inherit it from an ancestor
     process.

Avoid terminating processes

     Using the *note Process.terminate: 333f. method to stop a process
     is liable to cause any shared resources (such as locks, semaphores,
     pipes and queues) currently being used by the process to become
     broken or unavailable to other processes.

     Therefore it is probably best to only consider using *note
     Process.terminate: 333f. on processes which never use any shared
     resources.

Joining processes that use queues

     Bear in mind that a process that has put items in a queue will wait
     before terminating until all the buffered items are fed by the
     “feeder” thread to the underlying pipe.  (The child process can
     call the *note Queue.cancel_join_thread: 336b. method of the queue
     to avoid this behaviour.)

     This means that whenever you use a queue you need to make sure that
     all items which have been put on the queue will eventually be
     removed before the process is joined.  Otherwise you cannot be sure
     that processes which have put items on the queue will terminate.
     Remember also that non-daemonic processes will be joined
     automatically.

     An example which will deadlock is the following:

          from multiprocessing import Process, Queue

          def f(q):
              q.put('X' * 1000000)

          if __name__ == '__main__':
              queue = Queue()
              p = Process(target=f, args=(queue,))
              p.start()
              p.join()                    # this deadlocks
              obj = queue.get()

     A fix here would be to swap the last two lines (or simply remove
     the ‘p.join()’ line).

Explicitly pass resources to child processes

     On POSIX using the 'fork' start method, a child process can make
     use of a shared resource created in a parent process using a global
     resource.  However, it is better to pass the object as an argument
     to the constructor for the child process.

     Apart from making the code (potentially) compatible with Windows
     and the other start methods this also ensures that as long as the
     child process is still alive the object will not be garbage
     collected in the parent process.  This might be important if some
     resource is freed when the object is garbage collected in the
     parent process.

     So for instance

          from multiprocessing import Process, Lock

          def f():
              ... do something using "lock" ...

          if __name__ == '__main__':
              lock = Lock()
              for i in range(10):
                  Process(target=f).start()

     should be rewritten as

          from multiprocessing import Process, Lock

          def f(l):
              ... do something using "l" ...

          if __name__ == '__main__':
              lock = Lock()
              for i in range(10):
                  Process(target=f, args=(lock,)).start()

Beware of replacing *note sys.stdin: 540. with a “file like object”

     ‘multiprocessing’ originally unconditionally called:

          os.close(sys.stdin.fileno())

     in the ‘multiprocessing.Process._bootstrap()’ method — this
     resulted in issues with processes-in-processes.  This has been
     changed to:

          sys.stdin.close()
          sys.stdin = open(os.open(os.devnull, os.O_RDONLY), closefd=False)

     Which solves the fundamental issue of processes colliding with each
     other resulting in a bad file descriptor error, but introduces a
     potential danger to applications which replace *note sys.stdin():
     540. with a “file-like object” with output buffering.  This danger
     is that if multiple processes call *note close(): 1f6. on this
     file-like object, it could result in the same data being flushed to
     the object multiple times, resulting in corruption.

     If you write a file-like object and implement your own caching, you
     can make it fork-safe by storing the pid whenever you append to the
     cache, and discarding the cache when the pid changes.  For example:

          @property
          def cache(self):
              pid = os.getpid()
              if pid != self._pid:
                  self._pid = pid
                  self._cache = []
              return self._cache

     For more information, see bpo-5155(1), bpo-5313(2) and bpo-5331(3)

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=5155

   (2) https://bugs.python.org/issue?@action=redirect&bpo=5313

   (3) https://bugs.python.org/issue?@action=redirect&bpo=5331


File: python.info,  Node: The spawn and forkserver start methods,  Prev: All start methods,  Up: Programming guidelines

5.18.2.30 The 'spawn' and 'forkserver' start methods
....................................................

There are a few extra restrictions which don’t apply to the 'fork' start
method.

More picklability

     Ensure that all arguments to *note Process: b75. are picklable.
     Also, if you subclass ‘Process.__init__’, you must make sure that
     instances will be picklable when the *note Process.start: 13de.
     method is called.

Global variables

     Bear in mind that if code run in a child process tries to access a
     global variable, then the value it sees (if any) may not be the
     same as the value in the parent process at the time that *note
     Process.start: 13de. was called.

     However, global variables which are just module level constants
     cause no problems.
Safe importing of main module

     Make sure that the main module can be safely imported by a new
     Python interpreter without causing unintended side effects (such as
     starting a new process).

     For example, using the 'spawn' or 'forkserver' start method running
     the following module would fail with a *note RuntimeError: 195.:

          from multiprocessing import Process

          def foo():
              print('hello')

          p = Process(target=foo)
          p.start()

     Instead one should protect the “entry point” of the program by
     using ‘if __name__ == '__main__':’ as follows:

          from multiprocessing import Process, freeze_support, set_start_method

          def foo():
              print('hello')

          if __name__ == '__main__':
              freeze_support()
              set_start_method('spawn')
              p = Process(target=foo)
              p.start()

     (The ‘freeze_support()’ line can be omitted if the program will be
     run normally instead of frozen.)

     This allows the newly spawned Python interpreter to safely import
     the module and then run the module’s ‘foo()’ function.

     Similar restrictions apply if a pool or manager is created in the
     main module.


File: python.info,  Node: Examples<14>,  Prev: Programming guidelines,  Up: multiprocessing — Process-based parallelism

5.18.2.31 Examples
..................

Demonstration of how to create and use customized managers and proxies:

     from multiprocessing import freeze_support
     from multiprocessing.managers import BaseManager, BaseProxy
     import operator

     ##

     class Foo:
         def f(self):
             print('you called Foo.f()')
         def g(self):
             print('you called Foo.g()')
         def _h(self):
             print('you called Foo._h()')

     # A simple generator function
     def baz():
         for i in range(10):
             yield i*i

     # Proxy type for generator objects
     class GeneratorProxy(BaseProxy):
         _exposed_ = ['__next__']
         def __iter__(self):
             return self
         def __next__(self):
             return self._callmethod('__next__')

     # Function to return the operator module
     def get_operator_module():
         return operator

     ##

     class MyManager(BaseManager):
         pass

     # register the Foo class; make `f()` and `g()` accessible via proxy
     MyManager.register('Foo1', Foo)

     # register the Foo class; make `g()` and `_h()` accessible via proxy
     MyManager.register('Foo2', Foo, exposed=('g', '_h'))

     # register the generator function baz; use `GeneratorProxy` to make proxies
     MyManager.register('baz', baz, proxytype=GeneratorProxy)

     # register get_operator_module(); make public functions accessible via proxy
     MyManager.register('operator', get_operator_module)

     ##

     def test():
         manager = MyManager()
         manager.start()

         print('-' * 20)

         f1 = manager.Foo1()
         f1.f()
         f1.g()
         assert not hasattr(f1, '_h')
         assert sorted(f1._exposed_) == sorted(['f', 'g'])

         print('-' * 20)

         f2 = manager.Foo2()
         f2.g()
         f2._h()
         assert not hasattr(f2, 'f')
         assert sorted(f2._exposed_) == sorted(['g', '_h'])

         print('-' * 20)

         it = manager.baz()
         for i in it:
             print('<%d>' % i, end=' ')
         print()

         print('-' * 20)

         op = manager.operator()
         print('op.add(23, 45) =', op.add(23, 45))
         print('op.pow(2, 94) =', op.pow(2, 94))
         print('op._exposed_ =', op._exposed_)

     ##

     if __name__ == '__main__':
         freeze_support()
         test()

Using *note Pool: fa4.:

     import multiprocessing
     import time
     import random
     import sys

     #
     # Functions used by test code
     #

     def calculate(func, args):
         result = func(*args)
         return '%s says that %s%s = %s' % (
             multiprocessing.current_process().name,
             func.__name__, args, result
             )

     def calculatestar(args):
         return calculate(*args)

     def mul(a, b):
         time.sleep(0.5 * random.random())
         return a * b

     def plus(a, b):
         time.sleep(0.5 * random.random())
         return a + b

     def f(x):
         return 1.0 / (x - 5.0)

     def pow3(x):
         return x ** 3

     def noop(x):
         pass

     #
     # Test code
     #

     def test():
         PROCESSES = 4
         print('Creating pool with %d processes\n' % PROCESSES)

         with multiprocessing.Pool(PROCESSES) as pool:
             #
             # Tests
             #

             TASKS = [(mul, (i, 7)) for i in range(10)] + \
                     [(plus, (i, 8)) for i in range(10)]

             results = [pool.apply_async(calculate, t) for t in TASKS]
             imap_it = pool.imap(calculatestar, TASKS)
             imap_unordered_it = pool.imap_unordered(calculatestar, TASKS)

             print('Ordered results using pool.apply_async():')
             for r in results:
                 print('\t', r.get())
             print()

             print('Ordered results using pool.imap():')
             for x in imap_it:
                 print('\t', x)
             print()

             print('Unordered results using pool.imap_unordered():')
             for x in imap_unordered_it:
                 print('\t', x)
             print()

             print('Ordered results using pool.map() --- will block till complete:')
             for x in pool.map(calculatestar, TASKS):
                 print('\t', x)
             print()

             #
             # Test error handling
             #

             print('Testing error handling:')

             try:
                 print(pool.apply(f, (5,)))
             except ZeroDivisionError:
                 print('\tGot ZeroDivisionError as expected from pool.apply()')
             else:
                 raise AssertionError('expected ZeroDivisionError')

             try:
                 print(pool.map(f, list(range(10))))
             except ZeroDivisionError:
                 print('\tGot ZeroDivisionError as expected from pool.map()')
             else:
                 raise AssertionError('expected ZeroDivisionError')

             try:
                 print(list(pool.imap(f, list(range(10)))))
             except ZeroDivisionError:
                 print('\tGot ZeroDivisionError as expected from list(pool.imap())')
             else:
                 raise AssertionError('expected ZeroDivisionError')

             it = pool.imap(f, list(range(10)))
             for i in range(10):
                 try:
                     x = next(it)
                 except ZeroDivisionError:
                     if i == 5:
                         pass
                 except StopIteration:
                     break
                 else:
                     if i == 5:
                         raise AssertionError('expected ZeroDivisionError')

             assert i == 9
             print('\tGot ZeroDivisionError as expected from IMapIterator.next()')
             print()

             #
             # Testing timeouts
             #

             print('Testing ApplyResult.get() with timeout:', end=' ')
             res = pool.apply_async(calculate, TASKS[0])
             while 1:
                 sys.stdout.flush()
                 try:
                     sys.stdout.write('\n\t%s' % res.get(0.02))
                     break
                 except multiprocessing.TimeoutError:
                     sys.stdout.write('.')
             print()
             print()

             print('Testing IMapIterator.next() with timeout:', end=' ')
             it = pool.imap(calculatestar, TASKS)
             while 1:
                 sys.stdout.flush()
                 try:
                     sys.stdout.write('\n\t%s' % it.next(0.02))
                 except StopIteration:
                     break
                 except multiprocessing.TimeoutError:
                     sys.stdout.write('.')
             print()
             print()


     if __name__ == '__main__':
         multiprocessing.freeze_support()
         test()

An example showing how to use queues to feed tasks to a collection of
worker processes and collect the results:

     import time
     import random

     from multiprocessing import Process, Queue, current_process, freeze_support

     #
     # Function run by worker processes
     #

     def worker(input, output):
         for func, args in iter(input.get, 'STOP'):
             result = calculate(func, args)
             output.put(result)

     #
     # Function used to calculate result
     #

     def calculate(func, args):
         result = func(*args)
         return '%s says that %s%s = %s' % \
             (current_process().name, func.__name__, args, result)

     #
     # Functions referenced by tasks
     #

     def mul(a, b):
         time.sleep(0.5*random.random())
         return a * b

     def plus(a, b):
         time.sleep(0.5*random.random())
         return a + b

     #
     #
     #

     def test():
         NUMBER_OF_PROCESSES = 4
         TASKS1 = [(mul, (i, 7)) for i in range(20)]
         TASKS2 = [(plus, (i, 8)) for i in range(10)]

         # Create queues
         task_queue = Queue()
         done_queue = Queue()

         # Submit tasks
         for task in TASKS1:
             task_queue.put(task)

         # Start worker processes
         for i in range(NUMBER_OF_PROCESSES):
             Process(target=worker, args=(task_queue, done_queue)).start()

         # Get and print results
         print('Unordered results:')
         for i in range(len(TASKS1)):
             print('\t', done_queue.get())

         # Add more tasks using `put()`
         for task in TASKS2:
             task_queue.put(task)

         # Get and print some more results
         for i in range(len(TASKS2)):
             print('\t', done_queue.get())

         # Tell child processes to stop
         for i in range(NUMBER_OF_PROCESSES):
             task_queue.put('STOP')


     if __name__ == '__main__':
         freeze_support()
         test()


File: python.info,  Node: multiprocessing shared_memory — Shared memory for direct access across processes,  Next: The concurrent package,  Prev: multiprocessing — Process-based parallelism,  Up: Concurrent Execution

5.18.3 ‘multiprocessing.shared_memory’ — Shared memory for direct access across processes
-----------------------------------------------------------------------------------------

'Source code:' Lib/multiprocessing/shared_memory.py(1)

Added in version 3.8.

__________________________________________________________________

This module provides a class, *note SharedMemory: 176c, for the
allocation and management of shared memory to be accessed by one or more
processes on a multicore or symmetric multiprocessor (SMP) machine.  To
assist with the life-cycle management of shared memory especially across
distinct processes, a *note BaseManager: 3391. subclass, *note
SharedMemoryManager: 33cb, is also provided in the *note
multiprocessing.managers: 97. module.

In this module, shared memory refers to “POSIX style” shared memory
blocks (though is not necessarily implemented explicitly as such) and
does not refer to “distributed shared memory”.  This style of shared
memory permits distinct processes to potentially read and write to a
common (or shared) region of volatile memory.  Processes are
conventionally limited to only have access to their own process memory
space but shared memory permits the sharing of data between processes,
avoiding the need to instead send messages between processes containing
that data.  Sharing data directly via memory can provide significant
performance benefits compared to sharing data via disk or socket or
other communications requiring the serialization/deserialization and
copying of data.

 -- Class: multiprocessing.shared_memory.SharedMemory (name=None,
          create=False, size=0, *, track=True)

     Create an instance of the ‘SharedMemory’ class for either creating
     a new shared memory block or attaching to an existing shared memory
     block.  Each shared memory block is assigned a unique name.  In
     this way, one process can create a shared memory block with a
     particular name and a different process can attach to that same
     shared memory block using that same name.

     As a resource for sharing data across processes, shared memory
     blocks may outlive the original process that created them.  When
     one process no longer needs access to a shared memory block that
     might still be needed by other processes, the *note close(): 33cc.
     method should be called.  When a shared memory block is no longer
     needed by any process, the *note unlink(): 33cd. method should be
     called to ensure proper cleanup.


     Parameters:

        * ‘name’ (*note str: 44f.‘ | ’‘None’) – The unique name for the
          requested shared memory, specified as a string.  When creating
          a new shared memory block, if ‘None’ (the default) is supplied
          for the name, a novel name will be generated.

        * ‘create’ (*note bool: 46b.) – Control whether a new shared
          memory block is created (‘True’) or an existing shared memory
          block is attached (‘False’).

        * ‘size’ (*note int: 257.) – The requested number of bytes when
          creating a new shared memory block.  Because some platforms
          choose to allocate chunks of memory based upon that platform’s
          memory page size, the exact size of the shared memory block
          may be larger or equal to the size requested.  When attaching
          to an existing shared memory block, the 'size' parameter is
          ignored.

        * ‘track’ (*note bool: 46b.) – When ‘True’, register the shared
          memory block with a resource tracker process on platforms
          where the OS does not do this automatically.  The resource
          tracker ensures proper cleanup of the shared memory even if
          all other processes with access to the memory exit without
          doing so.  Python processes created from a common ancestor
          using *note multiprocessing: 94. facilities share a single
          resource tracker process, and the lifetime of shared memory
          segments is handled automatically among these processes.
          Python processes created in any other way will receive their
          own resource tracker when accessing shared memory with 'track'
          enabled.  This will cause the shared memory to be deleted by
          the resource tracker of the first process that terminates.  To
          avoid this issue, users of *note subprocess: d6. or standalone
          Python processes should set 'track' to ‘False’ when there is
          already another process in place that does the bookkeeping.
          'track' is ignored on Windows, which has its own tracking and
          automatically deletes shared memory when all handles to it
          have been closed.

     Changed in version 3.13: Added the 'track' parameter.

      -- Method: close ()

          Close the file descriptor/handle to the shared memory from
          this instance.  ‘close()’ should be called once access to the
          shared memory block from this instance is no longer needed.
          Depending on operating system, the underlying memory may or
          may not be freed even if all handles to it have been closed.
          To ensure proper cleanup, use the *note unlink(): 33cd.
          method.

      -- Method: unlink ()

          Delete the underlying shared memory block.  This should be
          called only once per shared memory block regardless of the
          number of handles to it, even in other processes.  ‘unlink()’
          and *note close(): 33cc. can be called in any order, but
          trying to access data inside a shared memory block after
          ‘unlink()’ may result in memory access errors, depending on
          platform.

          This method has no effect on Windows, where the only way to
          delete a shared memory block is to close all handles.

      -- Attribute: buf

          A memoryview of contents of the shared memory block.

      -- Attribute: name

          Read-only access to the unique name of the shared memory
          block.

      -- Attribute: size

          Read-only access to size in bytes of the shared memory block.

The following example demonstrates low-level use of *note SharedMemory:
176c. instances:

     >>> from multiprocessing import shared_memory
     >>> shm_a = shared_memory.SharedMemory(create=True, size=10)
     >>> type(shm_a.buf)
     <class 'memoryview'>
     >>> buffer = shm_a.buf
     >>> len(buffer)
     10
     >>> buffer[:4] = bytearray([22, 33, 44, 55])  # Modify multiple at once
     >>> buffer[4] = 100                           # Modify single byte at a time
     >>> # Attach to an existing shared memory block
     >>> shm_b = shared_memory.SharedMemory(shm_a.name)
     >>> import array
     >>> array.array('b', shm_b.buf[:5])  # Copy the data into a new array.array
     array('b', [22, 33, 44, 55, 100])
     >>> shm_b.buf[:5] = b'howdy'  # Modify via shm_b using bytes
     >>> bytes(shm_a.buf[:5])      # Access via shm_a
     b'howdy'
     >>> shm_b.close()   # Close each SharedMemory instance
     >>> shm_a.close()
     >>> shm_a.unlink()  # Call unlink only once to release the shared memory

The following example demonstrates a practical use of the *note
SharedMemory: 176c. class with NumPy arrays(2), accessing the same
‘numpy.ndarray’ from two distinct Python shells:

     >>> # In the first Python interactive shell
     >>> import numpy as np
     >>> a = np.array([1, 1, 2, 3, 5, 8])  # Start with an existing NumPy array
     >>> from multiprocessing import shared_memory
     >>> shm = shared_memory.SharedMemory(create=True, size=a.nbytes)
     >>> # Now create a NumPy array backed by shared memory
     >>> b = np.ndarray(a.shape, dtype=a.dtype, buffer=shm.buf)
     >>> b[:] = a[:]  # Copy the original data into shared memory
     >>> b
     array([1, 1, 2, 3, 5, 8])
     >>> type(b)
     <class 'numpy.ndarray'>
     >>> type(a)
     <class 'numpy.ndarray'>
     >>> shm.name  # We did not specify a name so one was chosen for us
     'psm_21467_46075'

     >>> # In either the same shell or a new Python shell on the same machine
     >>> import numpy as np
     >>> from multiprocessing import shared_memory
     >>> # Attach to the existing shared memory block
     >>> existing_shm = shared_memory.SharedMemory(name='psm_21467_46075')
     >>> # Note that a.shape is (6,) and a.dtype is np.int64 in this example
     >>> c = np.ndarray((6,), dtype=np.int64, buffer=existing_shm.buf)
     >>> c
     array([1, 1, 2, 3, 5, 8])
     >>> c[-1] = 888
     >>> c
     array([  1,   1,   2,   3,   5, 888])

     >>> # Back in the first Python interactive shell, b reflects this change
     >>> b
     array([  1,   1,   2,   3,   5, 888])

     >>> # Clean up from within the second Python shell
     >>> del c  # Unnecessary; merely emphasizing the array is no longer used
     >>> existing_shm.close()

     >>> # Clean up from within the first Python shell
     >>> del b  # Unnecessary; merely emphasizing the array is no longer used
     >>> shm.close()
     >>> shm.unlink()  # Free and release the shared memory block at the very end

 -- Class: multiprocessing.managers.SharedMemoryManager ([address[,
          authkey]])

     A subclass of *note multiprocessing.managers.BaseManager: 3391.
     which can be used for the management of shared memory blocks across
     processes.

     A call to *note start(): 3392. on a ‘SharedMemoryManager’ instance
     causes a new process to be started.  This new process’s sole
     purpose is to manage the life cycle of all shared memory blocks
     created through it.  To trigger the release of all shared memory
     blocks managed by that process, call *note shutdown(): 3393. on the
     instance.  This triggers a *note unlink(): 33cd. call on all of the
     *note SharedMemory: 33d1. objects managed by that process and then
     stops the process itself.  By creating ‘SharedMemory’ instances
     through a ‘SharedMemoryManager’, we avoid the need to manually
     track and trigger the freeing of shared memory resources.

     This class provides methods for creating and returning *note
     SharedMemory: 33d1. instances and for creating a list-like object
     (*note ShareableList: 33d2.) backed by shared memory.

     Refer to *note BaseManager: 3391. for a description of the
     inherited 'address' and 'authkey' optional input arguments and how
     they may be used to connect to an existing ‘SharedMemoryManager’
     service from other processes.

      -- Method: SharedMemory (size)

          Create and return a new *note SharedMemory: 33d1. object with
          the specified 'size' in bytes.

      -- Method: ShareableList (sequence)

          Create and return a new *note ShareableList: 33d2. object,
          initialized by the values from the input 'sequence'.

The following example demonstrates the basic mechanisms of a *note
SharedMemoryManager: 33cb.:

     >>> from multiprocessing.managers import SharedMemoryManager
     >>> smm = SharedMemoryManager()
     >>> smm.start()  # Start the process that manages the shared memory blocks
     >>> sl = smm.ShareableList(range(4))
     >>> sl
     ShareableList([0, 1, 2, 3], name='psm_6572_7512')
     >>> raw_shm = smm.SharedMemory(size=128)
     >>> another_sl = smm.ShareableList('alpha')
     >>> another_sl
     ShareableList(['a', 'l', 'p', 'h', 'a'], name='psm_6572_12221')
     >>> smm.shutdown()  # Calls unlink() on sl, raw_shm, and another_sl

The following example depicts a potentially more convenient pattern for
using *note SharedMemoryManager: 33cb. objects via the *note with: 5d5.
statement to ensure that all shared memory blocks are released after
they are no longer needed:

     >>> with SharedMemoryManager() as smm:
     ...     sl = smm.ShareableList(range(2000))
     ...     # Divide the work among two processes, storing partial results in sl
     ...     p1 = Process(target=do_work, args=(sl, 0, 1000))
     ...     p2 = Process(target=do_work, args=(sl, 1000, 2000))
     ...     p1.start()
     ...     p2.start()  # A multiprocessing.Pool might be more efficient
     ...     p1.join()
     ...     p2.join()   # Wait for all work to complete in both processes
     ...     total_result = sum(sl)  # Consolidate the partial results now in sl

When using a *note SharedMemoryManager: 33cb. in a *note with: 5d5.
statement, the shared memory blocks created using that manager are all
released when the ‘with’ statement’s code block finishes execution.

 -- Class: multiprocessing.shared_memory.ShareableList (sequence=None,
          *, name=None)

     Provide a mutable list-like object where all values stored within
     are stored in a shared memory block.  This constrains storable
     values to the following built-in data types:

        * *note int: 257. (signed 64-bit)

        * *note float: 2f7.

        * *note bool: 46b.

        * *note str: 44f. (less than 10M bytes each when encoded as
          UTF-8)

        * *note bytes: 1c2. (less than 10M bytes each)

        * ‘None’

     It also notably differs from the built-in *note list: 614. type in
     that these lists can not change their overall length (i.e.  no
     ‘append()’, ‘insert()’, etc.)  and do not support the dynamic
     creation of new ‘ShareableList’ instances via slicing.

     'sequence' is used in populating a new ‘ShareableList’ full of
     values.  Set to ‘None’ to instead attach to an already existing
     ‘ShareableList’ by its unique shared memory name.

     'name' is the unique name for the requested shared memory, as
     described in the definition for *note SharedMemory: 176c.  When
     attaching to an existing ‘ShareableList’, specify its shared memory
     block’s unique name while leaving 'sequence' set to ‘None’.

          Note: A known issue exists for *note bytes: 1c2. and *note
          str: 44f. values.  If they end with ‘\x00’ nul bytes or
          characters, those may be 'silently stripped' when fetching
          them by index from the ‘ShareableList’.  This
          ‘.rstrip(b'\x00')’ behavior is considered a bug and may go
          away in the future.  See gh-106939(3).

     For applications where rstripping of trailing nulls is a problem,
     work around it by always unconditionally appending an extra non-0
     byte to the end of such values when storing and unconditionally
     removing it when fetching:

          >>> from multiprocessing import shared_memory
          >>> nul_bug_demo = shared_memory.ShareableList(['?\x00', b'\x03\x02\x01\x00\x00\x00'])
          >>> nul_bug_demo[0]
          '?'
          >>> nul_bug_demo[1]
          b'\x03\x02\x01'
          >>> nul_bug_demo.shm.unlink()
          >>> padded = shared_memory.ShareableList(['?\x00\x07', b'\x03\x02\x01\x00\x00\x00\x07'])
          >>> padded[0][:-1]
          '?\x00'
          >>> padded[1][:-1]
          b'\x03\x02\x01\x00\x00\x00'
          >>> padded.shm.unlink()

      -- Method: count (value)

          Return the number of occurrences of 'value'.

      -- Method: index (value)

          Return first index position of 'value'.  Raise *note
          ValueError: 202. if 'value' is not present.

      -- Attribute: format

          Read-only attribute containing the *note struct: d5. packing
          format used by all currently stored values.

      -- Attribute: shm

          The *note SharedMemory: 176c. instance where the values are
          stored.

The following example demonstrates basic use of a *note ShareableList:
1b01. instance:

     >>> from multiprocessing import shared_memory
     >>> a = shared_memory.ShareableList(['howdy', b'HoWdY', -273.154, 100, None, True, 42])
     >>> [ type(entry) for entry in a ]
     [<class 'str'>, <class 'bytes'>, <class 'float'>, <class 'int'>, <class 'NoneType'>, <class 'bool'>, <class 'int'>]
     >>> a[2]
     -273.154
     >>> a[2] = -78.5
     >>> a[2]
     -78.5
     >>> a[2] = 'dry ice'  # Changing data types is supported as well
     >>> a[2]
     'dry ice'
     >>> a[2] = 'larger than previously allocated storage space'
     Traceback (most recent call last):
       ...
     ValueError: exceeds available storage for existing str
     >>> a[2]
     'dry ice'
     >>> len(a)
     7
     >>> a.index(42)
     6
     >>> a.count(b'howdy')
     0
     >>> a.count(b'HoWdY')
     1
     >>> a.shm.close()
     >>> a.shm.unlink()
     >>> del a  # Use of a ShareableList after call to unlink() is unsupported

The following example depicts how one, two, or many processes may access
the same *note ShareableList: 1b01. by supplying the name of the shared
memory block behind it:

     >>> b = shared_memory.ShareableList(range(5))         # In a first process
     >>> c = shared_memory.ShareableList(name=b.shm.name)  # In a second process
     >>> c
     ShareableList([0, 1, 2, 3, 4], name='...')
     >>> c[-1] = -999
     >>> b[-1]
     -999
     >>> b.shm.close()
     >>> c.shm.close()
     >>> c.shm.unlink()

The following examples demonstrates that *note ShareableList: 1b01. (and
underlying *note SharedMemory: 176c.) objects can be pickled and
unpickled if needed.  Note, that it will still be the same shared
object.  This happens, because the deserialized object has the same
unique name and is just attached to an existing object with the same
name (if the object is still alive):

     >>> import pickle
     >>> from multiprocessing import shared_memory
     >>> sl = shared_memory.ShareableList(range(10))
     >>> list(sl)
     [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

     >>> deserialized_sl = pickle.loads(pickle.dumps(sl))
     >>> list(deserialized_sl)
     [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

     >>> sl[0] = -1
     >>> deserialized_sl[1] = -2
     >>> list(sl)
     [-1, -2, 2, 3, 4, 5, 6, 7, 8, 9]
     >>> list(deserialized_sl)
     [-1, -2, 2, 3, 4, 5, 6, 7, 8, 9]

     >>> sl.shm.close()
     >>> sl.shm.unlink()

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/multiprocessing/shared_memory.py

   (2) https://numpy.org/

   (3) https://github.com/python/cpython/issues/106939


File: python.info,  Node: The concurrent package,  Next: concurrent futures — Launching parallel tasks,  Prev: multiprocessing shared_memory — Shared memory for direct access across processes,  Up: Concurrent Execution

5.18.4 The ‘concurrent’ package
-------------------------------

Currently, there is only one module in this package:

   * *note concurrent.futures: 21. – Launching parallel tasks


File: python.info,  Node: concurrent futures — Launching parallel tasks,  Next: subprocess — Subprocess management,  Prev: The concurrent package,  Up: Concurrent Execution

5.18.5 ‘concurrent.futures’ — Launching parallel tasks
------------------------------------------------------

Added in version 3.2.

'Source code:' Lib/concurrent/futures/thread.py(1) and
Lib/concurrent/futures/process.py(2)

__________________________________________________________________

The ‘concurrent.futures’ module provides a high-level interface for
asynchronously executing callables.

The asynchronous execution can be performed with threads, using *note
ThreadPoolExecutor: 745, or separate processes, using *note
ProcessPoolExecutor: 8f7.  Both implement the same interface, which is
defined by the abstract *note Executor: 33dd. class.

*note concurrent.futures.Future: 11f6. must not be confused with *note
asyncio.Future: bec, which is designed for use with *note asyncio: a.
tasks and coroutines.  See the *note asyncio’s Future: 33de.
documentation for a detailed comparison of the two.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

* Menu:

* Executor Objects::
* ThreadPoolExecutor::
* ProcessPoolExecutor::
* Future Objects::
* Module Functions::
* Exception classes::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/concurrent/futures/thread.py

   (2) 
https://github.com/python/cpython/tree/3.13/Lib/concurrent/futures/process.py


File: python.info,  Node: Executor Objects,  Next: ThreadPoolExecutor,  Up: concurrent futures — Launching parallel tasks

5.18.5.1 Executor Objects
.........................

 -- Class: concurrent.futures.Executor

     An abstract class that provides methods to execute calls
     asynchronously.  It should not be used directly, but through its
     concrete subclasses.

      -- Method: submit (fn, /, *args, **kwargs)

          Schedules the callable, 'fn', to be executed as ‘fn(*args,
          **kwargs)’ and returns a *note Future: 11f6. object
          representing the execution of the callable.

               with ThreadPoolExecutor(max_workers=1) as executor:
                   future = executor.submit(pow, 323, 1235)
                   print(future.result())

      -- Method: map (fn, *iterables, timeout=None, chunksize=1)

          Similar to *note map(fn, *iterables): 86a. except:

             * the 'iterables' are collected immediately rather than
               lazily;

             * 'fn' is executed asynchronously and several calls to 'fn'
               may be made concurrently.

          The returned iterator raises a *note TimeoutError: 83b. if
          *note __next__(): 1315. is called and the result isn’t
          available after 'timeout' seconds from the original call to
          ‘Executor.map()’.  'timeout' can be an int or a float.  If
          'timeout' is not specified or ‘None’, there is no limit to the
          wait time.

          If a 'fn' call raises an exception, then that exception will
          be raised when its value is retrieved from the iterator.

          When using *note ProcessPoolExecutor: 8f7, this method chops
          'iterables' into a number of chunks which it submits to the
          pool as separate tasks.  The (approximate) size of these
          chunks can be specified by setting 'chunksize' to a positive
          integer.  For very long iterables, using a large value for
          'chunksize' can significantly improve performance compared to
          the default size of 1.  With *note ThreadPoolExecutor: 745,
          'chunksize' has no effect.

          Changed in version 3.5: Added the 'chunksize' argument.

      -- Method: shutdown (wait=True, *, cancel_futures=False)

          Signal the executor that it should free any resources that it
          is using when the currently pending futures are done
          executing.  Calls to *note Executor.submit(): a91. and *note
          Executor.map(): e14. made after shutdown will raise *note
          RuntimeError: 195.

          If 'wait' is ‘True’ then this method will not return until all
          the pending futures are done executing and the resources
          associated with the executor have been freed.  If 'wait' is
          ‘False’ then this method will return immediately and the
          resources associated with the executor will be freed when all
          pending futures are done executing.  Regardless of the value
          of 'wait', the entire Python program will not exit until all
          pending futures are done executing.

          If 'cancel_futures' is ‘True’, this method will cancel all
          pending futures that the executor has not started running.
          Any futures that are completed or running won’t be cancelled,
          regardless of the value of 'cancel_futures'.

          If both 'cancel_futures' and 'wait' are ‘True’, all futures
          that the executor has started running will be completed prior
          to this method returning.  The remaining futures are
          cancelled.

          You can avoid having to call this method explicitly if you use
          the executor as a *note context manager: 5d7. via the *note
          with: 5d5. statement, which will shutdown the ‘Executor’
          (waiting as if ‘Executor.shutdown()’ were called with 'wait'
          set to ‘True’):

               import shutil
               with ThreadPoolExecutor(max_workers=4) as e:
                   e.submit(shutil.copy, 'src1.txt', 'dest1.txt')
                   e.submit(shutil.copy, 'src2.txt', 'dest2.txt')
                   e.submit(shutil.copy, 'src3.txt', 'dest3.txt')
                   e.submit(shutil.copy, 'src4.txt', 'dest4.txt')

          Changed in version 3.9: Added 'cancel_futures'.


File: python.info,  Node: ThreadPoolExecutor,  Next: ProcessPoolExecutor,  Prev: Executor Objects,  Up: concurrent futures — Launching parallel tasks

5.18.5.2 ThreadPoolExecutor
...........................

*note ThreadPoolExecutor: 745. is an *note Executor: 33dd. subclass that
uses a pool of threads to execute calls asynchronously.

Deadlocks can occur when the callable associated with a *note Future:
11f6. waits on the results of another ‘Future’.  For example:

     import time
     def wait_on_b():
         time.sleep(5)
         print(b.result())  # b will never complete because it is waiting on a.
         return 5

     def wait_on_a():
         time.sleep(5)
         print(a.result())  # a will never complete because it is waiting on b.
         return 6


     executor = ThreadPoolExecutor(max_workers=2)
     a = executor.submit(wait_on_b)
     b = executor.submit(wait_on_a)

And:

     def wait_on_future():
         f = executor.submit(pow, 5, 2)
         # This will never complete because there is only one worker thread and
         # it is executing this function.
         print(f.result())

     executor = ThreadPoolExecutor(max_workers=1)
     future = executor.submit(wait_on_future)
     # Note: calling future.result() would also cause a deadlock because
     # the single worker thread is already waiting for wait_on_future().

 -- Class: concurrent.futures.ThreadPoolExecutor (max_workers=None,
          thread_name_prefix='', initializer=None, initargs=())

     An *note Executor: 33dd. subclass that uses a pool of at most
     'max_workers' threads to execute calls asynchronously.

     All threads enqueued to ‘ThreadPoolExecutor’ will be joined before
     the interpreter can exit.  Note that the exit handler which does
     this is executed 'before' any exit handlers added using ‘atexit’.
     This means exceptions in the main thread must be caught and handled
     in order to signal threads to exit gracefully.  For this reason, it
     is recommended that ‘ThreadPoolExecutor’ not be used for
     long-running tasks.

     'initializer' is an optional callable that is called at the start
     of each worker thread; 'initargs' is a tuple of arguments passed to
     the initializer.  Should 'initializer' raise an exception, all
     currently pending jobs will raise a *note BrokenThreadPool: 33e1,
     as well as any attempt to submit more jobs to the pool.

     Changed in version 3.5: If 'max_workers' is ‘None’ or not given, it
     will default to the number of processors on the machine, multiplied
     by ‘5’, assuming that ‘ThreadPoolExecutor’ is often used to overlap
     I/O instead of CPU work and the number of workers should be higher
     than the number of workers for *note ProcessPoolExecutor: 8f7.

     Changed in version 3.6: Added the 'thread_name_prefix' parameter to
     allow users to control the *note threading.Thread: 956. names for
     worker threads created by the pool for easier debugging.

     Changed in version 3.7: Added the 'initializer' and 'initargs'
     arguments.

     Changed in version 3.8: Default value of 'max_workers' is changed
     to ‘min(32, os.cpu_count() + 4)’.  This default value preserves at
     least 5 workers for I/O bound tasks.  It utilizes at most 32 CPU
     cores for CPU bound tasks which release the GIL. And it avoids
     using very large resources implicitly on many-core machines.

     ThreadPoolExecutor now reuses idle worker threads before starting
     'max_workers' worker threads too.

     Changed in version 3.13: Default value of 'max_workers' is changed
     to ‘min(32, (os.process_cpu_count() or 1) + 4)’.

* Menu:

* ThreadPoolExecutor Example::


File: python.info,  Node: ThreadPoolExecutor Example,  Up: ThreadPoolExecutor

5.18.5.3 ThreadPoolExecutor Example
...................................

     import concurrent.futures
     import urllib.request

     URLS = ['http://www.foxnews.com/',
             'http://www.cnn.com/',
             'http://europe.wsj.com/',
             'http://www.bbc.co.uk/',
             'http://nonexistent-subdomain.python.org/']

     # Retrieve a single page and report the URL and contents
     def load_url(url, timeout):
         with urllib.request.urlopen(url, timeout=timeout) as conn:
             return conn.read()

     # We can use a with statement to ensure threads are cleaned up promptly
     with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:
         # Start the load operations and mark each future with its URL
         future_to_url = {executor.submit(load_url, url, 60): url for url in URLS}
         for future in concurrent.futures.as_completed(future_to_url):
             url = future_to_url[future]
             try:
                 data = future.result()
             except Exception as exc:
                 print('%r generated an exception: %s' % (url, exc))
             else:
                 print('%r page is %d bytes' % (url, len(data)))


File: python.info,  Node: ProcessPoolExecutor,  Next: Future Objects,  Prev: ThreadPoolExecutor,  Up: concurrent futures — Launching parallel tasks

5.18.5.4 ProcessPoolExecutor
............................

The *note ProcessPoolExecutor: 8f7. class is an *note Executor: 33dd.
subclass that uses a pool of processes to execute calls asynchronously.
‘ProcessPoolExecutor’ uses the *note multiprocessing: 94. module, which
allows it to side-step the *note Global Interpreter Lock: 148. but also
means that only picklable objects can be executed and returned.

The ‘__main__’ module must be importable by worker subprocesses.  This
means that *note ProcessPoolExecutor: 8f7. will not work in the
interactive interpreter.

Calling *note Executor: 33dd. or *note Future: 11f6. methods from a
callable submitted to a *note ProcessPoolExecutor: 8f7. will result in
deadlock.

Note that the restrictions on functions and arguments needing to
picklable as per *note multiprocessing.Process: b75. apply when using
*note submit(): a91. and *note map(): e14. on a *note
ProcessPoolExecutor: 8f7.  A function defined in a REPL or a lambda
should not be expected to work.

 -- Class: concurrent.futures.ProcessPoolExecutor (max_workers=None,
          mp_context=None, initializer=None, initargs=(),
          max_tasks_per_child=None)

     An *note Executor: 33dd. subclass that executes calls
     asynchronously using a pool of at most 'max_workers' processes.  If
     'max_workers' is ‘None’ or not given, it will default to *note
     os.process_cpu_count(): 1c4.  If 'max_workers' is less than or
     equal to ‘0’, then a *note ValueError: 202. will be raised.  On
     Windows, 'max_workers' must be less than or equal to ‘61’.  If it
     is not then ‘ValueError’ will be raised.  If 'max_workers' is
     ‘None’, then the default chosen will be at most ‘61’, even if more
     processors are available.  'mp_context' can be a *note
     multiprocessing: 94. context or ‘None’.  It will be used to launch
     the workers.  If 'mp_context' is ‘None’ or not given, the default
     ‘multiprocessing’ context is used.  See *note Contexts and start
     methods: 2c8.

     'initializer' is an optional callable that is called at the start
     of each worker process; 'initargs' is a tuple of arguments passed
     to the initializer.  Should 'initializer' raise an exception, all
     currently pending jobs will raise a *note BrokenProcessPool: 33e4,
     as well as any attempt to submit more jobs to the pool.

     'max_tasks_per_child' is an optional argument that specifies the
     maximum number of tasks a single process can execute before it will
     exit and be replaced with a fresh worker process.  By default
     'max_tasks_per_child' is ‘None’ which means worker processes will
     live as long as the pool.  When a max is specified, the “spawn”
     multiprocessing start method will be used by default in absence of
     a 'mp_context' parameter.  This feature is incompatible with the
     “fork” start method.

          Note: Bugs have been reported when using the
          'max_tasks_per_child' feature that can result in the
          ‘ProcessPoolExecutor’ hanging in some circumstances.  Follow
          its eventual resolution in gh-115634(1).

     Changed in version 3.3: When one of the worker processes terminates
     abruptly, a *note BrokenProcessPool: 33e4. error is now raised.
     Previously, behaviour was undefined but operations on the executor
     or its futures would often freeze or deadlock.

     Changed in version 3.7: The 'mp_context' argument was added to
     allow users to control the start_method for worker processes
     created by the pool.

     Added the 'initializer' and 'initargs' arguments.

          Note: The default *note multiprocessing: 94. start method (see
          *note Contexts and start methods: 2c8.) will change away from
          'fork' in Python 3.14.  Code that requires 'fork' be used for
          their ‘ProcessPoolExecutor’ should explicitly specify that by
          passing a ‘mp_context=multiprocessing.get_context("fork")’
          parameter.

     Changed in version 3.11: The 'max_tasks_per_child' argument was
     added to allow users to control the lifetime of workers in the
     pool.

     Changed in version 3.12: On POSIX systems, if your application has
     multiple threads and the *note multiprocessing: 94. context uses
     the ‘"fork"’ start method: The *note os.fork(): 197. function
     called internally to spawn workers may raise a *note
     DeprecationWarning: 1a5.  Pass a 'mp_context' configured to use a
     different start method.  See the ‘os.fork()’ documentation for
     further explanation.

     Changed in version 3.13: 'max_workers' uses *note
     os.process_cpu_count(): 1c4. by default, instead of *note
     os.cpu_count(): 1c5.

* Menu:

* ProcessPoolExecutor Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/115634


File: python.info,  Node: ProcessPoolExecutor Example,  Up: ProcessPoolExecutor

5.18.5.5 ProcessPoolExecutor Example
....................................

     import concurrent.futures
     import math

     PRIMES = [
         112272535095293,
         112582705942171,
         112272535095293,
         115280095190773,
         115797848077099,
         1099726899285419]

     def is_prime(n):
         if n < 2:
             return False
         if n == 2:
             return True
         if n % 2 == 0:
             return False

         sqrt_n = int(math.floor(math.sqrt(n)))
         for i in range(3, sqrt_n + 1, 2):
             if n % i == 0:
                 return False
         return True

     def main():
         with concurrent.futures.ProcessPoolExecutor() as executor:
             for number, prime in zip(PRIMES, executor.map(is_prime, PRIMES)):
                 print('%d is prime: %s' % (number, prime))

     if __name__ == '__main__':
         main()


File: python.info,  Node: Future Objects,  Next: Module Functions,  Prev: ProcessPoolExecutor,  Up: concurrent futures — Launching parallel tasks

5.18.5.6 Future Objects
.......................

The *note Future: 11f6. class encapsulates the asynchronous execution of
a callable.  ‘Future’ instances are created by *note Executor.submit():
a91.

 -- Class: concurrent.futures.Future

     Encapsulates the asynchronous execution of a callable.  ‘Future’
     instances are created by *note Executor.submit(): a91. and should
     not be created directly except for testing.

      -- Method: cancel ()

          Attempt to cancel the call.  If the call is currently being
          executed or finished running and cannot be cancelled then the
          method will return ‘False’, otherwise the call will be
          cancelled and the method will return ‘True’.

      -- Method: cancelled ()

          Return ‘True’ if the call was successfully cancelled.

      -- Method: running ()

          Return ‘True’ if the call is currently being executed and
          cannot be cancelled.

      -- Method: done ()

          Return ‘True’ if the call was successfully cancelled or
          finished running.

      -- Method: result (timeout=None)

          Return the value returned by the call.  If the call hasn’t yet
          completed then this method will wait up to 'timeout' seconds.
          If the call hasn’t completed in 'timeout' seconds, then a
          *note TimeoutError: 83b. will be raised.  'timeout' can be an
          int or float.  If 'timeout' is not specified or ‘None’, there
          is no limit to the wait time.

          If the future is cancelled before completing then *note
          CancelledError: 9e6. will be raised.

          If the call raised an exception, this method will raise the
          same exception.

      -- Method: exception (timeout=None)

          Return the exception raised by the call.  If the call hasn’t
          yet completed then this method will wait up to 'timeout'
          seconds.  If the call hasn’t completed in 'timeout' seconds,
          then a *note TimeoutError: 83b. will be raised.  'timeout' can
          be an int or float.  If 'timeout' is not specified or ‘None’,
          there is no limit to the wait time.

          If the future is cancelled before completing then *note
          CancelledError: 9e6. will be raised.

          If the call completed without raising, ‘None’ is returned.

      -- Method: add_done_callback (fn)

          Attaches the callable 'fn' to the future.  'fn' will be
          called, with the future as its only argument, when the future
          is cancelled or finishes running.

          Added callables are called in the order that they were added
          and are always called in a thread belonging to the process
          that added them.  If the callable raises an *note Exception:
          9e5. subclass, it will be logged and ignored.  If the callable
          raises a *note BaseException: 5be. subclass, the behavior is
          undefined.

          If the future has already completed or been cancelled, 'fn'
          will be called immediately.

     The following ‘Future’ methods are meant for use in unit tests and
     *note Executor: 33dd. implementations.

      -- Method: set_running_or_notify_cancel ()

          This method should only be called by *note Executor: 33dd.
          implementations before executing the work associated with the
          ‘Future’ and by unit tests.

          If the method returns ‘False’ then the ‘Future’ was cancelled,
          i.e.  *note Future.cancel(): 33e7. was called and returned
          ‘True’.  Any threads waiting on the ‘Future’ completing (i.e.
          through *note as_completed(): 175b. or *note wait(): 19a9.)
          will be woken up.

          If the method returns ‘True’ then the ‘Future’ was not
          cancelled and has been put in the running state, i.e.  calls
          to *note Future.running(): 33e9. will return ‘True’.

          This method can only be called once and cannot be called after
          *note Future.set_result(): 33ef. or *note
          Future.set_exception(): 33f0. have been called.

      -- Method: set_result (result)

          Sets the result of the work associated with the ‘Future’ to
          'result'.

          This method should only be used by *note Executor: 33dd.
          implementations and unit tests.

          Changed in version 3.8: This method raises *note
          concurrent.futures.InvalidStateError: 1715. if the ‘Future’ is
          already done.

      -- Method: set_exception (exception)

          Sets the result of the work associated with the ‘Future’ to
          the *note Exception: 9e5. 'exception'.

          This method should only be used by *note Executor: 33dd.
          implementations and unit tests.

          Changed in version 3.8: This method raises *note
          concurrent.futures.InvalidStateError: 1715. if the ‘Future’ is
          already done.


File: python.info,  Node: Module Functions,  Next: Exception classes,  Prev: Future Objects,  Up: concurrent futures — Launching parallel tasks

5.18.5.7 Module Functions
.........................

 -- Function: concurrent.futures.wait (fs, timeout=None,
          return_when=ALL_COMPLETED)

     Wait for the *note Future: 11f6. instances (possibly created by
     different *note Executor: 33dd. instances) given by 'fs' to
     complete.  Duplicate futures given to 'fs' are removed and will be
     returned only once.  Returns a named 2-tuple of sets.  The first
     set, named ‘done’, contains the futures that completed (finished or
     cancelled futures) before the wait completed.  The second set,
     named ‘not_done’, contains the futures that did not complete
     (pending or running futures).

     'timeout' can be used to control the maximum number of seconds to
     wait before returning.  'timeout' can be an int or float.  If
     'timeout' is not specified or ‘None’, there is no limit to the wait
     time.

     'return_when' indicates when this function should return.  It must
     be one of the following constants:

     Constant                                               Description
                                                            
     --------------------------------------------------------------------------------------------------------------
                                                            
      -- Data: concurrent.futures.FIRST_COMPLETED           The function will return when any future finishes or
                                                            is cancelled.
                                                            
                                                            
      -- Data: concurrent.futures.FIRST_EXCEPTION           The function will return when any future finishes by
                                                            raising an exception.  If no future raises an
                                                            exception then it is equivalent to
                                                            *note ALL_COMPLETED: 33f4.
                                                            
                                                            
      -- Data: concurrent.futures.ALL_COMPLETED             The function will return when all futures finish or
                                                            are cancelled.
                                                            

 -- Function: concurrent.futures.as_completed (fs, timeout=None)

     Returns an iterator over the *note Future: 11f6. instances
     (possibly created by different *note Executor: 33dd. instances)
     given by 'fs' that yields futures as they complete (finished or
     cancelled futures).  Any futures given by 'fs' that are duplicated
     will be returned once.  Any futures that completed before
     ‘as_completed()’ is called will be yielded first.  The returned
     iterator raises a *note TimeoutError: 83b. if *note __next__():
     1315. is called and the result isn’t available after 'timeout'
     seconds from the original call to ‘as_completed()’.  'timeout' can
     be an int or float.  If 'timeout' is not specified or ‘None’, there
     is no limit to the wait time.

See also
........

PEP 3148(1) – futures - execute computations asynchronously

     The proposal which described this feature for inclusion in the
     Python standard library.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3148/


File: python.info,  Node: Exception classes,  Prev: Module Functions,  Up: concurrent futures — Launching parallel tasks

5.18.5.8 Exception classes
..........................

 -- Exception: concurrent.futures.CancelledError

     Raised when a future is cancelled.

 -- Exception: concurrent.futures.TimeoutError

     A deprecated alias of ‘TimeoutError’, raised when a future
     operation exceeds the given timeout.

     Changed in version 3.11: This class was made an alias of
     ‘TimeoutError’.

 -- Exception: concurrent.futures.BrokenExecutor

     Derived from *note RuntimeError: 195, this exception class is
     raised when an executor is broken for some reason, and cannot be
     used to submit or execute new tasks.

     Added in version 3.7.

 -- Exception: concurrent.futures.InvalidStateError

     Raised when an operation is performed on a future that is not
     allowed in the current state.

     Added in version 3.8.

 -- Exception: concurrent.futures.thread.BrokenThreadPool

     Derived from *note BrokenExecutor: 33f7, this exception class is
     raised when one of the workers of a *note ThreadPoolExecutor: 745.
     has failed initializing.

     Added in version 3.7.

 -- Exception: concurrent.futures.process.BrokenProcessPool

     Derived from *note BrokenExecutor: 33f7. (formerly *note
     RuntimeError: 195.), this exception class is raised when one of the
     workers of a *note ProcessPoolExecutor: 8f7. has terminated in a
     non-clean fashion (for example, if it was killed from the outside).

     Added in version 3.3.


File: python.info,  Node: subprocess — Subprocess management,  Next: sched — Event scheduler,  Prev: concurrent futures — Launching parallel tasks,  Up: Concurrent Execution

5.18.6 ‘subprocess’ — Subprocess management
-------------------------------------------

'Source code:' Lib/subprocess.py(1)

__________________________________________________________________

The ‘subprocess’ module allows you to spawn new processes, connect to
their input/output/error pipes, and obtain their return codes.  This
module intends to replace several older modules and functions:

     os.system
     os.spawn*

Information about how the ‘subprocess’ module can be used to replace
these modules and functions can be found in the following sections.

See also
........

PEP 324(2) – PEP proposing the subprocess module

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

* Menu:

* Using the subprocess Module::
* Security Considerations::
* Popen Objects::
* Windows Popen Helpers::
* Older high-level API::
* Replacing Older Functions with the subprocess Module::
* Legacy Shell Invocation Functions::
* Notes: Notes<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/subprocess.py

   (2) https://peps.python.org/pep-0324/


File: python.info,  Node: Using the subprocess Module,  Next: Security Considerations,  Up: subprocess — Subprocess management

5.18.6.1 Using the ‘subprocess’ Module
......................................

The recommended approach to invoking subprocesses is to use the *note
run(): ba4. function for all use cases it can handle.  For more advanced
use cases, the underlying *note Popen: 199. interface can be used
directly.

 -- Function: subprocess.run (args, *, stdin=None, input=None,
          stdout=None, stderr=None, capture_output=False, shell=False,
          cwd=None, timeout=None, check=False, encoding=None,
          errors=None, text=None, env=None, universal_newlines=None,
          **other_popen_kwargs)

     Run the command described by 'args'.  Wait for command to complete,
     then return a *note CompletedProcess: ea7. instance.

     The arguments shown above are merely the most common ones,
     described below in *note Frequently Used Arguments: 33fc. (hence
     the use of keyword-only notation in the abbreviated signature).
     The full function signature is largely the same as that of the
     *note Popen: 199. constructor - most of the arguments to this
     function are passed through to that interface.  ('timeout',
     'input', 'check', and 'capture_output' are not.)

     If 'capture_output' is true, stdout and stderr will be captured.
     When used, the internal *note Popen: 199. object is automatically
     created with 'stdout' and 'stderr' both set to *note PIPE: ba5.
     The 'stdout' and 'stderr' arguments may not be supplied at the same
     time as 'capture_output'.  If you wish to capture and combine both
     streams into one, set 'stdout' to ‘PIPE’ and 'stderr' to *note
     STDOUT: 33fd, instead of using 'capture_output'.

     A 'timeout' may be specified in seconds, it is internally passed on
     to *note Popen.communicate(): 15f2.  If the timeout expires, the
     child process will be killed and waited for.  The *note
     TimeoutExpired: 15f3. exception will be re-raised after the child
     process has terminated.  The initial process creation itself cannot
     be interrupted on many platform APIs so you are not guaranteed to
     see a timeout exception until at least after however long process
     creation takes.

     The 'input' argument is passed to *note Popen.communicate(): 15f2.
     and thus to the subprocess’s stdin.  If used it must be a byte
     sequence, or a string if 'encoding' or 'errors' is specified or
     'text' is true.  When used, the internal *note Popen: 199. object
     is automatically created with 'stdin' set to *note PIPE: ba5, and
     the 'stdin' argument may not be used as well.

     If 'check' is true, and the process exits with a non-zero exit
     code, a *note CalledProcessError: 136e. exception will be raised.
     Attributes of that exception hold the arguments, the exit code, and
     stdout and stderr if they were captured.

     If 'encoding' or 'errors' are specified, or 'text' is true, file
     objects for stdin, stdout and stderr are opened in text mode using
     the specified 'encoding' and 'errors' or the *note
     io.TextIOWrapper: 7bf. default.  The 'universal_newlines' argument
     is equivalent to 'text' and is provided for backwards
     compatibility.  By default, file objects are opened in binary mode.

     If 'env' is not ‘None’, it must be a mapping that defines the
     environment variables for the new process; these are used instead
     of the default behavior of inheriting the current process’
     environment.  It is passed directly to *note Popen: 199.  This
     mapping can be str to str on any platform or bytes to bytes on
     POSIX platforms much like *note os.environ: 11fe. or *note
     os.environb: 125c.

     Examples:

          >>> subprocess.run(["ls", "-l"])  # doesn't capture output
          CompletedProcess(args=['ls', '-l'], returncode=0)

          >>> subprocess.run("exit 1", shell=True, check=True)
          Traceback (most recent call last):
            ...
          subprocess.CalledProcessError: Command 'exit 1' returned non-zero exit status 1

          >>> subprocess.run(["ls", "-l", "/dev/null"], capture_output=True)
          CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
          stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n', stderr=b'')

     Added in version 3.5.

     Changed in version 3.6: Added 'encoding' and 'errors' parameters

     Changed in version 3.7: Added the 'text' parameter, as a more
     understandable alias of 'universal_newlines'.  Added the
     'capture_output' parameter.

     Changed in version 3.12: Changed Windows shell search order for
     ‘shell=True’.  The current directory and ‘%PATH%’ are replaced with
     ‘%COMSPEC%’ and ‘%SystemRoot%\System32\cmd.exe’.  As a result,
     dropping a malicious program named ‘cmd.exe’ into a current
     directory no longer works.

 -- Class: subprocess.CompletedProcess

     The return value from *note run(): ba4, representing a process that
     has finished.

      -- Attribute: args

          The arguments used to launch the process.  This may be a list
          or a string.

      -- Attribute: returncode

          Exit status of the child process.  Typically, an exit status
          of 0 indicates that it ran successfully.

          A negative value ‘-N’ indicates that the child was terminated
          by signal ‘N’ (POSIX only).

      -- Attribute: stdout

          Captured stdout from the child process.  A bytes sequence, or
          a string if *note run(): ba4. was called with an encoding,
          errors, or text=True.  ‘None’ if stdout was not captured.

          If you ran the process with ‘stderr=subprocess.STDOUT’, stdout
          and stderr will be combined in this attribute, and *note
          stderr: 3401. will be ‘None’.

      -- Attribute: stderr

          Captured stderr from the child process.  A bytes sequence, or
          a string if *note run(): ba4. was called with an encoding,
          errors, or text=True.  ‘None’ if stderr was not captured.

      -- Method: check_returncode ()

          If *note returncode: 33ff. is non-zero, raise a *note
          CalledProcessError: 136e.

     Added in version 3.5.

 -- Data: subprocess.DEVNULL

     Special value that can be used as the 'stdin', 'stdout' or 'stderr'
     argument to *note Popen: 199. and indicates that the special file
     *note os.devnull: 1bc3. will be used.

     Added in version 3.3.

 -- Data: subprocess.PIPE

     Special value that can be used as the 'stdin', 'stdout' or 'stderr'
     argument to *note Popen: 199. and indicates that a pipe to the
     standard stream should be opened.  Most useful with *note
     Popen.communicate(): 15f2.

 -- Data: subprocess.STDOUT

     Special value that can be used as the 'stderr' argument to *note
     Popen: 199. and indicates that standard error should go into the
     same handle as standard output.

 -- Exception: subprocess.SubprocessError

     Base class for all other exceptions from this module.

     Added in version 3.3.

 -- Exception: subprocess.TimeoutExpired

     Subclass of *note SubprocessError: 3403, raised when a timeout
     expires while waiting for a child process.

      -- Attribute: cmd

          Command that was used to spawn the child process.

      -- Attribute: timeout

          Timeout in seconds.

      -- Attribute: output

          Output of the child process if it was captured by *note run():
          ba4. or *note check_output(): ffb.  Otherwise, ‘None’.  This
          is always *note bytes: 1c2. when any output was captured
          regardless of the ‘text=True’ setting.  It may remain ‘None’
          instead of ‘b''’ when no output was observed.

      -- Attribute: stdout

          Alias for output, for symmetry with *note stderr: 3408.

      -- Attribute: stderr

          Stderr output of the child process if it was captured by *note
          run(): ba4.  Otherwise, ‘None’.  This is always *note bytes:
          1c2. when stderr output was captured regardless of the
          ‘text=True’ setting.  It may remain ‘None’ instead of ‘b''’
          when no stderr output was observed.

     Added in version 3.3.

     Changed in version 3.5: 'stdout' and 'stderr' attributes added

 -- Exception: subprocess.CalledProcessError

     Subclass of *note SubprocessError: 3403, raised when a process run
     by *note check_call(): 3409, *note check_output(): ffb, or *note
     run(): ba4. (with ‘check=True’) returns a non-zero exit status.

      -- Attribute: returncode

          Exit status of the child process.  If the process exited due
          to a signal, this will be the negative signal number.

      -- Attribute: cmd

          Command that was used to spawn the child process.

      -- Attribute: output

          Output of the child process if it was captured by *note run():
          ba4. or *note check_output(): ffb.  Otherwise, ‘None’.

      -- Attribute: stdout

          Alias for output, for symmetry with *note stderr: 340e.

      -- Attribute: stderr

          Stderr output of the child process if it was captured by *note
          run(): ba4.  Otherwise, ‘None’.

     Changed in version 3.5: 'stdout' and 'stderr' attributes added

* Menu:

* Frequently Used Arguments::
* Popen Constructor::
* Exceptions: Exceptions<11>.


File: python.info,  Node: Frequently Used Arguments,  Next: Popen Constructor,  Up: Using the subprocess Module

5.18.6.2 Frequently Used Arguments
..................................

To support a wide variety of use cases, the *note Popen: 199.
constructor (and the convenience functions) accept a large number of
optional arguments.  For most typical use cases, many of these arguments
can be safely left at their default values.  The arguments that are most
commonly needed are:

     'args' is required for all calls and should be a string, or a
     sequence of program arguments.  Providing a sequence of arguments
     is generally preferred, as it allows the module to take care of any
     required escaping and quoting of arguments (e.g.  to permit spaces
     in file names).  If passing a single string, either 'shell' must be
     *note True: c2d. (see below) or else the string must simply name
     the program to be executed without specifying any arguments.

     'stdin', 'stdout' and 'stderr' specify the executed program’s
     standard input, standard output and standard error file handles,
     respectively.  Valid values are ‘None’, *note PIPE: ba5, *note
     DEVNULL: 1192, an existing file descriptor (a positive integer),
     and an existing *note file object: 1208. with a valid file
     descriptor.  With the default settings of ‘None’, no redirection
     will occur.  ‘PIPE’ indicates that a new pipe to the child should
     be created.  ‘DEVNULL’ indicates that the special file *note
     os.devnull: 1bc3. will be used.  Additionally, 'stderr' can be
     *note STDOUT: 33fd, which indicates that the stderr data from the
     child process should be captured into the same file handle as for
     'stdout'.

     If 'encoding' or 'errors' are specified, or 'text' (also known as
     'universal_newlines') is true, the file objects 'stdin', 'stdout'
     and 'stderr' will be opened in text mode using the 'encoding' and
     'errors' specified in the call or the defaults for *note
     io.TextIOWrapper: 7bf.

     For 'stdin', line ending characters ‘'\n'’ in the input will be
     converted to the default line separator *note os.linesep: 2334.
     For 'stdout' and 'stderr', all line endings in the output will be
     converted to ‘'\n'’.  For more information see the documentation of
     the *note io.TextIOWrapper: 7bf. class when the 'newline' argument
     to its constructor is ‘None’.

     If text mode is not used, 'stdin', 'stdout' and 'stderr' will be
     opened as binary streams.  No encoding or line ending conversion is
     performed.

     Changed in version 3.6: Added the 'encoding' and 'errors'
     parameters.

     Changed in version 3.7: Added the 'text' parameter as an alias for
     'universal_newlines'.

          Note: The newlines attribute of the file objects *note
          Popen.stdin: 3410, *note Popen.stdout: 3411. and *note
          Popen.stderr: 3412. are not updated by the *note
          Popen.communicate(): 15f2. method.

     If 'shell' is ‘True’, the specified command will be executed
     through the shell.  This can be useful if you are using Python
     primarily for the enhanced control flow it offers over most system
     shells and still want convenient access to other shell features
     such as shell pipes, filename wildcards, environment variable
     expansion, and expansion of ‘~’ to a user’s home directory.
     However, note that Python itself offers implementations of many
     shell-like features (in particular, *note glob: 64, *note fnmatch:
     5c, *note os.walk(): 4ac, *note os.path.expandvars(): 1427, *note
     os.path.expanduser(): a21, and *note shutil: c5.).

     Changed in version 3.3: When 'universal_newlines' is ‘True’, the
     class uses the encoding *note locale.getpreferredencoding(False):
     53d. instead of ‘locale.getpreferredencoding()’.  See the *note
     io.TextIOWrapper: 7bf. class for more information on this change.

          Note: Read the *note Security Considerations: 3413. section
          before using ‘shell=True’.

These options, along with all of the other options, are described in
more detail in the *note Popen: 199. constructor documentation.


File: python.info,  Node: Popen Constructor,  Next: Exceptions<11>,  Prev: Frequently Used Arguments,  Up: Using the subprocess Module

5.18.6.3 Popen Constructor
..........................

The underlying process creation and management in this module is handled
by the *note Popen: 199. class.  It offers a lot of flexibility so that
developers are able to handle the less common cases not covered by the
convenience functions.

 -- Class: subprocess.Popen (args, bufsize=-1, executable=None,
          stdin=None, stdout=None, stderr=None, preexec_fn=None,
          close_fds=True, shell=False, cwd=None, env=None,
          universal_newlines=None, startupinfo=None, creationflags=0,
          restore_signals=True, start_new_session=False, pass_fds=(), *,
          group=None, extra_groups=None, user=None, umask=-1,
          encoding=None, errors=None, text=None, pipesize=-1,
          process_group=None)

     Execute a child program in a new process.  On POSIX, the class uses
     *note os.execvpe(): 2db8.-like behavior to execute the child
     program.  On Windows, the class uses the Windows ‘CreateProcess()’
     function.  The arguments to ‘Popen’ are as follows.

     'args' should be a sequence of program arguments or else a single
     string or *note path-like object: 2a0.  By default, the program to
     execute is the first item in 'args' if 'args' is a sequence.  If
     'args' is a string, the interpretation is platform-dependent and
     described below.  See the 'shell' and 'executable' arguments for
     additional differences from the default behavior.  Unless otherwise
     stated, it is recommended to pass 'args' as a sequence.

          Warning: For maximum reliability, use a fully qualified path
          for the executable.  To search for an unqualified name on
          ‘PATH’, use *note shutil.which(): 4b7.  On all platforms,
          passing *note sys.executable: 3bb. is the recommended way to
          launch the current Python interpreter again, and use the ‘-m’
          command-line format to launch an installed module.

          Resolving the path of 'executable' (or the first item of
          'args') is platform dependent.  For POSIX, see *note
          os.execvpe(): 2db8, and note that when resolving or searching
          for the executable path, 'cwd' overrides the current working
          directory and 'env' can override the ‘PATH’ environment
          variable.  For Windows, see the documentation of the
          ‘lpApplicationName’ and ‘lpCommandLine’ parameters of WinAPI
          ‘CreateProcess’, and note that when resolving or searching for
          the executable path with ‘shell=False’, 'cwd' does not
          override the current working directory and 'env' cannot
          override the ‘PATH’ environment variable.  Using a full path
          avoids all of these variations.

     An example of passing some arguments to an external program as a
     sequence is:

          Popen(["/usr/bin/git", "commit", "-m", "Fixes a bug."])

     On POSIX, if 'args' is a string, the string is interpreted as the
     name or path of the program to execute.  However, this can only be
     done if not passing arguments to the program.

          Note: It may not be obvious how to break a shell command into
          a sequence of arguments, especially in complex cases.  *note
          shlex.split(): 53f. can illustrate how to determine the
          correct tokenization for 'args':

               >>> import shlex, subprocess
               >>> command_line = input()
               /bin/vikings -input eggs.txt -output "spam spam.txt" -cmd "echo '$MONEY'"
               >>> args = shlex.split(command_line)
               >>> print(args)
               ['/bin/vikings', '-input', 'eggs.txt', '-output', 'spam spam.txt', '-cmd', "echo '$MONEY'"]
               >>> p = subprocess.Popen(args) # Success!

          Note in particular that options (such as '-input') and
          arguments (such as 'eggs.txt') that are separated by
          whitespace in the shell go in separate list elements, while
          arguments that need quoting or backslash escaping when used in
          the shell (such as filenames containing spaces or the 'echo'
          command shown above) are single list elements.

     On Windows, if 'args' is a sequence, it will be converted to a
     string in a manner described in *note Converting an argument
     sequence to a string on Windows: 3415.  This is because the
     underlying ‘CreateProcess()’ operates on strings.

     Changed in version 3.6: 'args' parameter accepts a *note path-like
     object: 2a0. if 'shell' is ‘False’ and a sequence containing
     path-like objects on POSIX.

     Changed in version 3.8: 'args' parameter accepts a *note path-like
     object: 2a0. if 'shell' is ‘False’ and a sequence containing bytes
     and path-like objects on Windows.

     The 'shell' argument (which defaults to ‘False’) specifies whether
     to use the shell as the program to execute.  If 'shell' is ‘True’,
     it is recommended to pass 'args' as a string rather than as a
     sequence.

     On POSIX with ‘shell=True’, the shell defaults to ‘/bin/sh’.  If
     'args' is a string, the string specifies the command to execute
     through the shell.  This means that the string must be formatted
     exactly as it would be when typed at the shell prompt.  This
     includes, for example, quoting or backslash escaping filenames with
     spaces in them.  If 'args' is a sequence, the first item specifies
     the command string, and any additional items will be treated as
     additional arguments to the shell itself.  That is to say, ‘Popen’
     does the equivalent of:

          Popen(['/bin/sh', '-c', args[0], args[1], ...])

     On Windows with ‘shell=True’, the ‘COMSPEC’ environment variable
     specifies the default shell.  The only time you need to specify
     ‘shell=True’ on Windows is when the command you wish to execute is
     built into the shell (e.g.  ‘dir’ or ‘copy’).  You do not need
     ‘shell=True’ to run a batch file or console-based executable.

          Note: Read the *note Security Considerations: 3413. section
          before using ‘shell=True’.

     'bufsize' will be supplied as the corresponding argument to the
     *note open(): 51f. function when creating the stdin/stdout/stderr
     pipe file objects:

        - ‘0’ means unbuffered (read and write are one system call and
          can return short)

        - ‘1’ means line buffered (only usable if ‘text=True’ or
          ‘universal_newlines=True’)

        - any other positive value means use a buffer of approximately
          that size

        - negative bufsize (the default) means the system default of
          io.DEFAULT_BUFFER_SIZE will be used.

     Changed in version 3.3.1: 'bufsize' now defaults to -1 to enable
     buffering by default to match the behavior that most code expects.
     In versions prior to Python 3.2.4 and 3.3.1 it incorrectly
     defaulted to ‘0’ which was unbuffered and allowed short reads.
     This was unintentional and did not match the behavior of Python 2
     as most code expected.

     The 'executable' argument specifies a replacement program to
     execute.  It is very seldom needed.  When ‘shell=False’,
     'executable' replaces the program to execute specified by 'args'.
     However, the original 'args' is still passed to the program.  Most
     programs treat the program specified by 'args' as the command name,
     which can then be different from the program actually executed.  On
     POSIX, the 'args' name becomes the display name for the executable
     in utilities such as ‘ps’.  If ‘shell=True’, on POSIX the
     'executable' argument specifies a replacement shell for the default
     ‘/bin/sh’.

     Changed in version 3.6: 'executable' parameter accepts a *note
     path-like object: 2a0. on POSIX.

     Changed in version 3.8: 'executable' parameter accepts a bytes and
     *note path-like object: 2a0. on Windows.

     Changed in version 3.12: Changed Windows shell search order for
     ‘shell=True’.  The current directory and ‘%PATH%’ are replaced with
     ‘%COMSPEC%’ and ‘%SystemRoot%\System32\cmd.exe’.  As a result,
     dropping a malicious program named ‘cmd.exe’ into a current
     directory no longer works.

     'stdin', 'stdout' and 'stderr' specify the executed program’s
     standard input, standard output and standard error file handles,
     respectively.  Valid values are ‘None’, *note PIPE: ba5, *note
     DEVNULL: 1192, an existing file descriptor (a positive integer),
     and an existing *note file object: 1208. with a valid file
     descriptor.  With the default settings of ‘None’, no redirection
     will occur.  ‘PIPE’ indicates that a new pipe to the child should
     be created.  ‘DEVNULL’ indicates that the special file *note
     os.devnull: 1bc3. will be used.  Additionally, 'stderr' can be
     *note STDOUT: 33fd, which indicates that the stderr data from the
     applications should be captured into the same file handle as for
     'stdout'.

     If 'preexec_fn' is set to a callable object, this object will be
     called in the child process just before the child is executed.
     (POSIX only)

          Warning: The 'preexec_fn' parameter is NOT SAFE to use in the
          presence of threads in your application.  The child process
          could deadlock before exec is called.

          Note: If you need to modify the environment for the child use
          the 'env' parameter rather than doing it in a 'preexec_fn'.
          The 'start_new_session' and 'process_group' parameters should
          take the place of code using 'preexec_fn' to call *note
          os.setsid(): 1b65. or *note os.setpgid(): 2d1c. in the child.

     Changed in version 3.8: The 'preexec_fn' parameter is no longer
     supported in subinterpreters.  The use of the parameter in a
     subinterpreter raises *note RuntimeError: 195.  The new restriction
     may affect applications that are deployed in mod_wsgi, uWSGI, and
     other embedded environments.

     If 'close_fds' is true, all file descriptors except ‘0’, ‘1’ and
     ‘2’ will be closed before the child process is executed.  Otherwise
     when 'close_fds' is false, file descriptors obey their inheritable
     flag as described in *note Inheritance of File Descriptors: f30.

     On Windows, if 'close_fds' is true then no handles will be
     inherited by the child process unless explicitly passed in the
     ‘handle_list’ element of *note STARTUPINFO.lpAttributeList: c2e, or
     by standard handle redirection.

     Changed in version 3.2: The default for 'close_fds' was changed
     from *note False: b4f. to what is described above.

     Changed in version 3.7: On Windows the default for 'close_fds' was
     changed from *note False: b4f. to *note True: c2d. when redirecting
     the standard handles.  It’s now possible to set 'close_fds' to
     ‘True’ when redirecting the standard handles.

     'pass_fds' is an optional sequence of file descriptors to keep open
     between the parent and child.  Providing any 'pass_fds' forces
     'close_fds' to be *note True: c2d.  (POSIX only)

     Changed in version 3.2: The 'pass_fds' parameter was added.

     If 'cwd' is not ‘None’, the function changes the working directory
     to 'cwd' before executing the child.  'cwd' can be a string, bytes
     or *note path-like: 2a0. object.  On POSIX, the function looks for
     'executable' (or for the first item in 'args') relative to 'cwd' if
     the executable path is a relative path.

     Changed in version 3.6: 'cwd' parameter accepts a *note path-like
     object: 2a0. on POSIX.

     Changed in version 3.7: 'cwd' parameter accepts a *note path-like
     object: 2a0. on Windows.

     Changed in version 3.8: 'cwd' parameter accepts a bytes object on
     Windows.

     If 'restore_signals' is true (the default) all signals that Python
     has set to SIG_IGN are restored to SIG_DFL in the child process
     before the exec.  Currently this includes the SIGPIPE, SIGXFZ and
     SIGXFSZ signals.  (POSIX only)

     Changed in version 3.2: 'restore_signals' was added.

     If 'start_new_session' is true the ‘setsid()’ system call will be
     made in the child process prior to the execution of the subprocess.

     *note Availability: 1ef7.: POSIX

     Changed in version 3.2: 'start_new_session' was added.

     If 'process_group' is a non-negative integer, the ‘setpgid(0,
     value)’ system call will be made in the child process prior to the
     execution of the subprocess.

     *note Availability: 1ef7.: POSIX

     Changed in version 3.11: 'process_group' was added.

     If 'group' is not ‘None’, the setregid() system call will be made
     in the child process prior to the execution of the subprocess.  If
     the provided value is a string, it will be looked up via *note
     grp.getgrnam(): 3416. and the value in ‘gr_gid’ will be used.  If
     the value is an integer, it will be passed verbatim.  (POSIX only)

     *note Availability: 1ef7.: POSIX

     Added in version 3.9.

     If 'extra_groups' is not ‘None’, the setgroups() system call will
     be made in the child process prior to the execution of the
     subprocess.  Strings provided in 'extra_groups' will be looked up
     via *note grp.getgrnam(): 3416. and the values in ‘gr_gid’ will be
     used.  Integer values will be passed verbatim.  (POSIX only)

     *note Availability: 1ef7.: POSIX

     Added in version 3.9.

     If 'user' is not ‘None’, the setreuid() system call will be made in
     the child process prior to the execution of the subprocess.  If the
     provided value is a string, it will be looked up via *note
     pwd.getpwnam(): 3417. and the value in ‘pw_uid’ will be used.  If
     the value is an integer, it will be passed verbatim.  (POSIX only)

          Note: Specifying 'user' will not drop existing supplementary
          group memberships!  The caller must also pass
          ‘extra_groups=()’ to reduce the group membership of the child
          process for security purposes.

     *note Availability: 1ef7.: POSIX

     Added in version 3.9.

     If 'umask' is not negative, the umask() system call will be made in
     the child process prior to the execution of the subprocess.

     *note Availability: 1ef7.: POSIX

     Added in version 3.9.

     If 'env' is not ‘None’, it must be a mapping that defines the
     environment variables for the new process; these are used instead
     of the default behavior of inheriting the current process’
     environment.  This mapping can be str to str on any platform or
     bytes to bytes on POSIX platforms much like *note os.environ: 11fe.
     or *note os.environb: 125c.

          Note: If specified, 'env' must provide any variables required
          for the program to execute.  On Windows, in order to run a
          side-by-side assembly(1) the specified 'env' 'must' include a
          valid ‘%SystemRoot%’.

     If 'encoding' or 'errors' are specified, or 'text' is true, the
     file objects 'stdin', 'stdout' and 'stderr' are opened in text mode
     with the specified 'encoding' and 'errors', as described above in
     *note Frequently Used Arguments: 33fc.  The 'universal_newlines'
     argument is equivalent to 'text' and is provided for backwards
     compatibility.  By default, file objects are opened in binary mode.

     Added in version 3.6: 'encoding' and 'errors' were added.

     Added in version 3.7: 'text' was added as a more readable alias for
     'universal_newlines'.

     If given, 'startupinfo' will be a *note STARTUPINFO: 3418. object,
     which is passed to the underlying ‘CreateProcess’ function.

     If given, 'creationflags', can be one or more of the following
     flags:

        * *note CREATE_NEW_CONSOLE: 3419.

        * *note CREATE_NEW_PROCESS_GROUP: 341a.

        * *note ABOVE_NORMAL_PRIORITY_CLASS: 341b.

        * *note BELOW_NORMAL_PRIORITY_CLASS: 341c.

        * *note HIGH_PRIORITY_CLASS: 341d.

        * *note IDLE_PRIORITY_CLASS: 341e.

        * *note NORMAL_PRIORITY_CLASS: 341f.

        * *note REALTIME_PRIORITY_CLASS: 3420.

        * *note CREATE_NO_WINDOW: 3421.

        * *note DETACHED_PROCESS: 3422.

        * *note CREATE_DEFAULT_ERROR_MODE: 3423.

        * *note CREATE_BREAKAWAY_FROM_JOB: 3424.

     'pipesize' can be used to change the size of the pipe when *note
     PIPE: ba5. is used for 'stdin', 'stdout' or 'stderr'.  The size of
     the pipe is only changed on platforms that support this (only Linux
     at this time of writing).  Other platforms will ignore this
     parameter.

     Changed in version 3.10: Added the 'pipesize' parameter.

     Popen objects are supported as context managers via the *note with:
     5d5. statement: on exit, standard file descriptors are closed, and
     the process is waited for.

          with Popen(["ifconfig"], stdout=PIPE) as proc:
              log.write(proc.stdout.read())

     Popen and the other functions in this module that use it raise an
     *note auditing event: 1a15. ‘subprocess.Popen’ with arguments
     ‘executable’, ‘args’, ‘cwd’, and ‘env’.  The value for ‘args’ may
     be a single string or a list of strings, depending on platform.

     Changed in version 3.2: Added context manager support.

     Changed in version 3.6: Popen destructor now emits a *note
     ResourceWarning: 244. warning if the child process is still
     running.

     Changed in version 3.8: Popen can use *note os.posix_spawn(): 220.
     in some cases for better performance.  On Windows Subsystem for
     Linux and QEMU User Emulation, Popen constructor using
     ‘os.posix_spawn()’ no longer raise an exception on errors like
     missing program, but the child process fails with a non-zero *note
     returncode: aa1.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Side-by-Side_Assembly


File: python.info,  Node: Exceptions<11>,  Prev: Popen Constructor,  Up: Using the subprocess Module

5.18.6.4 Exceptions
...................

Exceptions raised in the child process, before the new program has
started to execute, will be re-raised in the parent.

The most common exception raised is *note OSError: 41a.  This occurs,
for example, when trying to execute a non-existent file.  Applications
should prepare for ‘OSError’ exceptions.  Note that, when ‘shell=True’,
‘OSError’ will be raised by the child only if the selected shell itself
was not found.  To determine if the shell failed to find the requested
application, it is necessary to check the return code or output from the
subprocess.

A *note ValueError: 202. will be raised if *note Popen: 199. is called
with invalid arguments.

*note check_call(): 3409. and *note check_output(): ffb. will raise
*note CalledProcessError: 136e. if the called process returns a non-zero
return code.

All of the functions and methods that accept a 'timeout' parameter, such
as *note run(): ba4. and *note Popen.communicate(): 15f2. will raise
*note TimeoutExpired: 15f3. if the timeout expires before the process
exits.

Exceptions defined in this module all inherit from *note
SubprocessError: 3403.

Added in version 3.3: The *note SubprocessError: 3403. base class was
added.


File: python.info,  Node: Security Considerations,  Next: Popen Objects,  Prev: Using the subprocess Module,  Up: subprocess — Subprocess management

5.18.6.5 Security Considerations
................................

Unlike some other popen functions, this library will not implicitly
choose to call a system shell.  This means that all characters,
including shell metacharacters, can safely be passed to child processes.
If the shell is invoked explicitly, via ‘shell=True’, it is the
application’s responsibility to ensure that all whitespace and
metacharacters are quoted appropriately to avoid shell injection(1)
vulnerabilities.  On *note some platforms: 3427, it is possible to use
*note shlex.quote(): 27d. for this escaping.

On Windows, batch files (‘*.bat’ or ‘*.cmd’) may be launched by the
operating system in a system shell regardless of the arguments passed to
this library.  This could result in arguments being parsed according to
shell rules, but without any escaping added by Python.  If you are
intentionally launching a batch file with arguments from untrusted
sources, consider passing ‘shell=True’ to allow Python to escape special
characters.  See gh-114539(2) for additional discussion.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Shell_injection#Shell_injection

   (2) https://github.com/python/cpython/issues/114539


File: python.info,  Node: Popen Objects,  Next: Windows Popen Helpers,  Prev: Security Considerations,  Up: subprocess — Subprocess management

5.18.6.6 Popen Objects
......................

Instances of the *note Popen: 199. class have the following methods:

 -- Method: Popen.poll ()

     Check if child process has terminated.  Set and return *note
     returncode: aa1. attribute.  Otherwise, returns ‘None’.

 -- Method: Popen.wait (timeout=None)

     Wait for child process to terminate.  Set and return *note
     returncode: aa1. attribute.

     If the process does not terminate after 'timeout' seconds, raise a
     *note TimeoutExpired: 15f3. exception.  It is safe to catch this
     exception and retry the wait.

          Note: This will deadlock when using ‘stdout=PIPE’ or
          ‘stderr=PIPE’ and the child process generates enough output to
          a pipe such that it blocks waiting for the OS pipe buffer to
          accept more data.  Use *note Popen.communicate(): 15f2. when
          using pipes to avoid that.

          Note: When the ‘timeout’ parameter is not ‘None’, then (on
          POSIX) the function is implemented using a busy loop
          (non-blocking call and short sleeps).  Use the *note asyncio:
          a. module for an asynchronous wait: see *note
          asyncio.create_subprocess_exec: a86.

     Changed in version 3.3: 'timeout' was added.

 -- Method: Popen.communicate (input=None, timeout=None)

     Interact with process: Send data to stdin.  Read data from stdout
     and stderr, until end-of-file is reached.  Wait for process to
     terminate and set the *note returncode: aa1. attribute.  The
     optional 'input' argument should be data to be sent to the child
     process, or ‘None’, if no data should be sent to the child.  If
     streams were opened in text mode, 'input' must be a string.
     Otherwise, it must be bytes.

     ‘communicate()’ returns a tuple ‘(stdout_data, stderr_data)’.  The
     data will be strings if streams were opened in text mode;
     otherwise, bytes.

     Note that if you want to send data to the process’s stdin, you need
     to create the Popen object with ‘stdin=PIPE’.  Similarly, to get
     anything other than ‘None’ in the result tuple, you need to give
     ‘stdout=PIPE’ and/or ‘stderr=PIPE’ too.

     If the process does not terminate after 'timeout' seconds, a *note
     TimeoutExpired: 15f3. exception will be raised.  Catching this
     exception and retrying communication will not lose any output.
     Supplying 'input' to a subsequent post-timeout ‘communicate()’ call
     is in undefined behavior and may become an error in the future.

     The child process is not killed if the timeout expires, so in order
     to cleanup properly a well-behaved application should kill the
     child process and finish communication:

          proc = subprocess.Popen(...)
          try:
              outs, errs = proc.communicate(timeout=15)
          except TimeoutExpired:
              proc.kill()
              outs, errs = proc.communicate()

     After a call to ‘communicate()’ raises *note TimeoutExpired: 15f3,
     do not call *note wait(): d0b.  Use an additional ‘communicate()’
     call to finish handling pipes and populate the *note returncode:
     aa1. attribute.

          Note: The data read is buffered in memory, so do not use this
          method if the data size is large or unlimited.

     Changed in version 3.3: 'timeout' was added.

 -- Method: Popen.send_signal (signal)

     Sends the signal 'signal' to the child.

     Do nothing if the process completed.

          Note: On Windows, SIGTERM is an alias for *note terminate():
          142a.  CTRL_C_EVENT and CTRL_BREAK_EVENT can be sent to
          processes started with a 'creationflags' parameter which
          includes ‘CREATE_NEW_PROCESS_GROUP’.

 -- Method: Popen.terminate ()

     Stop the child.  On POSIX OSs the method sends *note SIGTERM: 142d.
     to the child.  On Windows the Win32 API function
     ‘TerminateProcess()’ is called to stop the child.

 -- Method: Popen.kill ()

     Kills the child.  On POSIX OSs the function sends SIGKILL to the
     child.  On Windows ‘kill()’ is an alias for *note terminate():
     142a.

The following attributes are also set by the class for you to access.
Reassigning them to new values is unsupported:

 -- Attribute: Popen.args

     The 'args' argument as it was passed to *note Popen: 199. – a
     sequence of program arguments or else a single string.

     Added in version 3.3.

 -- Attribute: Popen.stdin

     If the 'stdin' argument was *note PIPE: ba5, this attribute is a
     writeable stream object as returned by *note open(): 51f.  If the
     'encoding' or 'errors' arguments were specified or the 'text' or
     'universal_newlines' argument was ‘True’, the stream is a text
     stream, otherwise it is a byte stream.  If the 'stdin' argument was
     not ‘PIPE’, this attribute is ‘None’.

 -- Attribute: Popen.stdout

     If the 'stdout' argument was *note PIPE: ba5, this attribute is a
     readable stream object as returned by *note open(): 51f.  Reading
     from the stream provides output from the child process.  If the
     'encoding' or 'errors' arguments were specified or the 'text' or
     'universal_newlines' argument was ‘True’, the stream is a text
     stream, otherwise it is a byte stream.  If the 'stdout' argument
     was not ‘PIPE’, this attribute is ‘None’.

 -- Attribute: Popen.stderr

     If the 'stderr' argument was *note PIPE: ba5, this attribute is a
     readable stream object as returned by *note open(): 51f.  Reading
     from the stream provides error output from the child process.  If
     the 'encoding' or 'errors' arguments were specified or the 'text'
     or 'universal_newlines' argument was ‘True’, the stream is a text
     stream, otherwise it is a byte stream.  If the 'stderr' argument
     was not ‘PIPE’, this attribute is ‘None’.

     Warning: Use *note communicate(): 15f2. rather than *note
     .stdin.write: 3410, *note .stdout.read: 3411. or *note
     .stderr.read: 3412. to avoid deadlocks due to any of the other OS
     pipe buffers filling up and blocking the child process.

 -- Attribute: Popen.pid

     The process ID of the child process.

     Note that if you set the 'shell' argument to ‘True’, this is the
     process ID of the spawned shell.

 -- Attribute: Popen.returncode

     The child return code.  Initially ‘None’, *note returncode: aa1. is
     set by a call to the *note poll(): 3429, *note wait(): d0b, or
     *note communicate(): 15f2. methods if they detect that the process
     has terminated.

     A ‘None’ value indicates that the process hadn’t yet terminated at
     the time of the last method call.

     A negative value ‘-N’ indicates that the child was terminated by
     signal ‘N’ (POSIX only).

     When ‘shell=True’, the return code reflects the exit status of the
     shell itself (e.g.  ‘/bin/sh’), which may map signals to codes such
     as ‘128+N’.  See the documentation of the shell (for example, the
     Bash manual’s Exit Status) for details.


File: python.info,  Node: Windows Popen Helpers,  Next: Older high-level API,  Prev: Popen Objects,  Up: subprocess — Subprocess management

5.18.6.7 Windows Popen Helpers
..............................

The *note STARTUPINFO: 3418. class and following constants are only
available on Windows.

 -- Class: subprocess.STARTUPINFO (*, dwFlags=0, hStdInput=None,
          hStdOutput=None, hStdError=None, wShowWindow=0,
          lpAttributeList=None)

     Partial support of the Windows STARTUPINFO(1) structure is used for
     *note Popen: 199. creation.  The following attributes can be set by
     passing them as keyword-only arguments.

     Changed in version 3.7: Keyword-only argument support was added.

      -- Attribute: dwFlags

          A bit field that determines whether certain ‘STARTUPINFO’
          attributes are used when the process creates a window.

               si = subprocess.STARTUPINFO()
               si.dwFlags = subprocess.STARTF_USESTDHANDLES | subprocess.STARTF_USESHOWWINDOW

      -- Attribute: hStdInput

          If *note dwFlags: 342d. specifies *note STARTF_USESTDHANDLES:
          342f, this attribute is the standard input handle for the
          process.  If ‘STARTF_USESTDHANDLES’ is not specified, the
          default for standard input is the keyboard buffer.

      -- Attribute: hStdOutput

          If *note dwFlags: 342d. specifies *note STARTF_USESTDHANDLES:
          342f, this attribute is the standard output handle for the
          process.  Otherwise, this attribute is ignored and the default
          for standard output is the console window’s buffer.

      -- Attribute: hStdError

          If *note dwFlags: 342d. specifies *note STARTF_USESTDHANDLES:
          342f, this attribute is the standard error handle for the
          process.  Otherwise, this attribute is ignored and the default
          for standard error is the console window’s buffer.

      -- Attribute: wShowWindow

          If *note dwFlags: 342d. specifies *note STARTF_USESHOWWINDOW:
          3433, this attribute can be any of the values that can be
          specified in the ‘nCmdShow’ parameter for the ShowWindow(2)
          function, except for ‘SW_SHOWDEFAULT’.  Otherwise, this
          attribute is ignored.

          *note SW_HIDE: 3434. is provided for this attribute.  It is
          used when *note Popen: 199. is called with ‘shell=True’.

      -- Attribute: lpAttributeList

          A dictionary of additional attributes for process creation as
          given in ‘STARTUPINFOEX’, see UpdateProcThreadAttribute(3).

          Supported attributes:

          'handle_list'

               Sequence of handles that will be inherited.  'close_fds'
               must be true if non-empty.

               The handles must be temporarily made inheritable by *note
               os.set_handle_inheritable(): f34. when passed to the
               *note Popen: 199. constructor, else *note OSError: 41a.
               will be raised with Windows error
               ‘ERROR_INVALID_PARAMETER’ (87).

                    Warning: In a multithreaded process, use caution to
                    avoid leaking handles that are marked inheritable
                    when combining this feature with concurrent calls to
                    other process creation functions that inherit all
                    handles such as *note os.system(): 14ac.  This also
                    applies to standard handle redirection, which
                    temporarily creates inheritable handles.

          Added in version 3.7.

* Menu:

* Windows Constants::

   ---------- Footnotes ----------

   (1) https://msdn.microsoft.com/en-us/library/ms686331(v=vs.85).aspx

   (2) https://msdn.microsoft.com/en-us/library/ms633548(v=vs.85).aspx

   (3) 
https://msdn.microsoft.com/en-us/library/windows/desktop/ms686880(v=vs.85).aspx


File: python.info,  Node: Windows Constants,  Up: Windows Popen Helpers

5.18.6.8 Windows Constants
..........................

The ‘subprocess’ module exposes the following constants.

 -- Data: subprocess.STD_INPUT_HANDLE

     The standard input device.  Initially, this is the console input
     buffer, ‘CONIN$’.

 -- Data: subprocess.STD_OUTPUT_HANDLE

     The standard output device.  Initially, this is the active console
     screen buffer, ‘CONOUT$’.

 -- Data: subprocess.STD_ERROR_HANDLE

     The standard error device.  Initially, this is the active console
     screen buffer, ‘CONOUT$’.

 -- Data: subprocess.SW_HIDE

     Hides the window.  Another window will be activated.

 -- Data: subprocess.STARTF_USESTDHANDLES

     Specifies that the *note STARTUPINFO.hStdInput: 342e, *note
     STARTUPINFO.hStdOutput: 3430, and *note STARTUPINFO.hStdError:
     3431. attributes contain additional information.

 -- Data: subprocess.STARTF_USESHOWWINDOW

     Specifies that the *note STARTUPINFO.wShowWindow: 3432. attribute
     contains additional information.

 -- Data: subprocess.STARTF_FORCEONFEEDBACK

     A *note STARTUPINFO.dwFlags: 342d. parameter to specify that the
     'Working in Background' mouse cursor will be displayed while a
     process is launching.  This is the default behavior for GUI
     processes.

     Added in version 3.13.

 -- Data: subprocess.STARTF_FORCEOFFFEEDBACK

     A *note STARTUPINFO.dwFlags: 342d. parameter to specify that the
     mouse cursor will not be changed when launching a process.

     Added in version 3.13.

 -- Data: subprocess.CREATE_NEW_CONSOLE

     The new process has a new console, instead of inheriting its
     parent’s console (the default).

 -- Data: subprocess.CREATE_NEW_PROCESS_GROUP

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process group will be created.  This flag is necessary for using
     *note os.kill(): 13b4. on the subprocess.

     This flag is ignored if *note CREATE_NEW_CONSOLE: 3419. is
     specified.

 -- Data: subprocess.ABOVE_NORMAL_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have an above average priority.

     Added in version 3.7.

 -- Data: subprocess.BELOW_NORMAL_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have a below average priority.

     Added in version 3.7.

 -- Data: subprocess.HIGH_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have a high priority.

     Added in version 3.7.

 -- Data: subprocess.IDLE_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have an idle (lowest) priority.

     Added in version 3.7.

 -- Data: subprocess.NORMAL_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have a normal priority.  (default)

     Added in version 3.7.

 -- Data: subprocess.REALTIME_PRIORITY_CLASS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will have realtime priority.  You should almost never use
     REALTIME_PRIORITY_CLASS, because this interrupts system threads
     that manage mouse input, keyboard input, and background disk
     flushing.  This class can be appropriate for applications that
     “talk” directly to hardware or that perform brief tasks that should
     have limited interruptions.

     Added in version 3.7.

 -- Data: subprocess.CREATE_NO_WINDOW

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will not create a window.

     Added in version 3.7.

 -- Data: subprocess.DETACHED_PROCESS

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process will not inherit its parent’s console.  This value cannot
     be used with CREATE_NEW_CONSOLE.

     Added in version 3.7.

 -- Data: subprocess.CREATE_DEFAULT_ERROR_MODE

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process does not inherit the error mode of the calling process.
     Instead, the new process gets the default error mode.  This feature
     is particularly useful for multithreaded shell applications that
     run with hard errors disabled.

     Added in version 3.7.

 -- Data: subprocess.CREATE_BREAKAWAY_FROM_JOB

     A *note Popen: 199. ‘creationflags’ parameter to specify that a new
     process is not associated with the job.

     Added in version 3.7.


File: python.info,  Node: Older high-level API,  Next: Replacing Older Functions with the subprocess Module,  Prev: Windows Popen Helpers,  Up: subprocess — Subprocess management

5.18.6.9 Older high-level API
.............................

Prior to Python 3.5, these three functions comprised the high level API
to subprocess.  You can now use *note run(): ba4. in many cases, but
lots of existing code calls these functions.

 -- Function: subprocess.call (args, *, stdin=None, stdout=None,
          stderr=None, shell=False, cwd=None, timeout=None,
          **other_popen_kwargs)

     Run the command described by 'args'.  Wait for command to complete,
     then return the *note returncode: aa1. attribute.

     Code needing to capture stdout or stderr should use *note run():
     ba4. instead:

          run(...).returncode

     To suppress stdout or stderr, supply a value of *note DEVNULL:
     1192.

     The arguments shown above are merely some common ones.  The full
     function signature is the same as that of the *note Popen: 199.
     constructor - this function passes all supplied arguments other
     than 'timeout' directly through to that interface.

          Note: Do not use ‘stdout=PIPE’ or ‘stderr=PIPE’ with this
          function.  The child process will block if it generates enough
          output to a pipe to fill up the OS pipe buffer as the pipes
          are not being read from.

     Changed in version 3.3: 'timeout' was added.

     Changed in version 3.12: Changed Windows shell search order for
     ‘shell=True’.  The current directory and ‘%PATH%’ are replaced with
     ‘%COMSPEC%’ and ‘%SystemRoot%\System32\cmd.exe’.  As a result,
     dropping a malicious program named ‘cmd.exe’ into a current
     directory no longer works.

 -- Function: subprocess.check_call (args, *, stdin=None, stdout=None,
          stderr=None, shell=False, cwd=None, timeout=None,
          **other_popen_kwargs)

     Run command with arguments.  Wait for command to complete.  If the
     return code was zero then return, otherwise raise *note
     CalledProcessError: 136e.  The ‘CalledProcessError’ object will
     have the return code in the *note returncode: 340a. attribute.  If
     ‘check_call()’ was unable to start the process it will propagate
     the exception that was raised.

     Code needing to capture stdout or stderr should use *note run():
     ba4. instead:

          run(..., check=True)

     To suppress stdout or stderr, supply a value of *note DEVNULL:
     1192.

     The arguments shown above are merely some common ones.  The full
     function signature is the same as that of the *note Popen: 199.
     constructor - this function passes all supplied arguments other
     than 'timeout' directly through to that interface.

          Note: Do not use ‘stdout=PIPE’ or ‘stderr=PIPE’ with this
          function.  The child process will block if it generates enough
          output to a pipe to fill up the OS pipe buffer as the pipes
          are not being read from.

     Changed in version 3.3: 'timeout' was added.

     Changed in version 3.12: Changed Windows shell search order for
     ‘shell=True’.  The current directory and ‘%PATH%’ are replaced with
     ‘%COMSPEC%’ and ‘%SystemRoot%\System32\cmd.exe’.  As a result,
     dropping a malicious program named ‘cmd.exe’ into a current
     directory no longer works.

 -- Function: subprocess.check_output (args, *, stdin=None, stderr=None,
          shell=False, cwd=None, encoding=None, errors=None,
          universal_newlines=None, timeout=None, text=None,
          **other_popen_kwargs)

     Run command with arguments and return its output.

     If the return code was non-zero it raises a *note
     CalledProcessError: 136e.  The ‘CalledProcessError’ object will
     have the return code in the *note returncode: 340a. attribute and
     any output in the *note output: 340c. attribute.

     This is equivalent to:

          run(..., check=True, stdout=PIPE).stdout

     The arguments shown above are merely some common ones.  The full
     function signature is largely the same as that of *note run(): ba4.
     - most arguments are passed directly through to that interface.
     One API deviation from ‘run()’ behavior exists: passing
     ‘input=None’ will behave the same as ‘input=b''’ (or ‘input=''’,
     depending on other arguments) rather than using the parent’s
     standard input file handle.

     By default, this function will return the data as encoded bytes.
     The actual encoding of the output data may depend on the command
     being invoked, so the decoding to text will often need to be
     handled at the application level.

     This behaviour may be overridden by setting 'text', 'encoding',
     'errors', or 'universal_newlines' to ‘True’ as described in *note
     Frequently Used Arguments: 33fc. and *note run(): ba4.

     To also capture standard error in the result, use
     ‘stderr=subprocess.STDOUT’:

          >>> subprocess.check_output(
          ...     "ls non_existent_file; exit 0",
          ...     stderr=subprocess.STDOUT,
          ...     shell=True)
          'ls: non_existent_file: No such file or directory\n'

     Added in version 3.1.

     Changed in version 3.3: 'timeout' was added.

     Changed in version 3.4: Support for the 'input' keyword argument
     was added.

     Changed in version 3.6: 'encoding' and 'errors' were added.  See
     *note run(): ba4. for details.

     Added in version 3.7: 'text' was added as a more readable alias for
     'universal_newlines'.

     Changed in version 3.12: Changed Windows shell search order for
     ‘shell=True’.  The current directory and ‘%PATH%’ are replaced with
     ‘%COMSPEC%’ and ‘%SystemRoot%\System32\cmd.exe’.  As a result,
     dropping a malicious program named ‘cmd.exe’ into a current
     directory no longer works.


File: python.info,  Node: Replacing Older Functions with the subprocess Module,  Next: Legacy Shell Invocation Functions,  Prev: Older high-level API,  Up: subprocess — Subprocess management

5.18.6.10 Replacing Older Functions with the ‘subprocess’ Module
................................................................

In this section, “a becomes b” means that b can be used as a replacement
for a.

     Note: All “a” functions in this section fail (more or less)
     silently if the executed program cannot be found; the “b”
     replacements raise *note OSError: 41a. instead.

     In addition, the replacements using *note check_output(): ffb. will
     fail with a *note CalledProcessError: 136e. if the requested
     operation produces a non-zero return code.  The output is still
     available as the *note output: 340c. attribute of the raised
     exception.

In the following examples, we assume that the relevant functions have
already been imported from the ‘subprocess’ module.

* Menu:

* Replacing /bin/sh shell command substitution::
* Replacing shell pipeline::
* Replacing os.system(): Replacing os system.
* Replacing the os.spawn family: Replacing the os spawn family.
* Replacing os.popen(), os.popen2(), os.popen3(): Replacing os popen os popen2 os popen3.
* Replacing functions from the popen2 module::


File: python.info,  Node: Replacing /bin/sh shell command substitution,  Next: Replacing shell pipeline,  Up: Replacing Older Functions with the subprocess Module

5.18.6.11 Replacing ‘/bin/sh’ shell command substitution
........................................................

     output=$(mycmd myarg)

becomes:

     output = check_output(["mycmd", "myarg"])


File: python.info,  Node: Replacing shell pipeline,  Next: Replacing os system,  Prev: Replacing /bin/sh shell command substitution,  Up: Replacing Older Functions with the subprocess Module

5.18.6.12 Replacing shell pipeline
..................................

     output=$(dmesg | grep hda)

becomes:

     p1 = Popen(["dmesg"], stdout=PIPE)
     p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE)
     p1.stdout.close()  # Allow p1 to receive a SIGPIPE if p2 exits.
     output = p2.communicate()[0]

The ‘p1.stdout.close()’ call after starting the p2 is important in order
for p1 to receive a SIGPIPE if p2 exits before p1.

Alternatively, for trusted input, the shell’s own pipeline support may
still be used directly:

     output=$(dmesg | grep hda)

becomes:

     output = check_output("dmesg | grep hda", shell=True)


File: python.info,  Node: Replacing os system,  Next: Replacing the os spawn family,  Prev: Replacing shell pipeline,  Up: Replacing Older Functions with the subprocess Module

5.18.6.13 Replacing ‘os.system()’
.................................

     sts = os.system("mycmd" + " myarg")
     # becomes
     retcode = call("mycmd" + " myarg", shell=True)

Notes:

   * Calling the program through the shell is usually not required.

   * The *note call(): ba6. return value is encoded differently to that
     of *note os.system(): 14ac.

   * The *note os.system(): 14ac. function ignores SIGINT and SIGQUIT
     signals while the command is running, but the caller must do this
     separately when using the ‘subprocess’ module.

A more realistic example would look like this:

     try:
         retcode = call("mycmd" + " myarg", shell=True)
         if retcode < 0:
             print("Child was terminated by signal", -retcode, file=sys.stderr)
         else:
             print("Child returned", retcode, file=sys.stderr)
     except OSError as e:
         print("Execution failed:", e, file=sys.stderr)


File: python.info,  Node: Replacing the os spawn family,  Next: Replacing os popen os popen2 os popen3,  Prev: Replacing os system,  Up: Replacing Older Functions with the subprocess Module

5.18.6.14 Replacing the ‘os.spawn’ family
.........................................

P_NOWAIT example:

     pid = os.spawnlp(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg")
     ==>
     pid = Popen(["/bin/mycmd", "myarg"]).pid

P_WAIT example:

     retcode = os.spawnlp(os.P_WAIT, "/bin/mycmd", "mycmd", "myarg")
     ==>
     retcode = call(["/bin/mycmd", "myarg"])

Vector example:

     os.spawnvp(os.P_NOWAIT, path, args)
     ==>
     Popen([path] + args[1:])

Environment example:

     os.spawnlpe(os.P_NOWAIT, "/bin/mycmd", "mycmd", "myarg", env)
     ==>
     Popen(["/bin/mycmd", "myarg"], env={"PATH": "/usr/bin"})


File: python.info,  Node: Replacing os popen os popen2 os popen3,  Next: Replacing functions from the popen2 module,  Prev: Replacing the os spawn family,  Up: Replacing Older Functions with the subprocess Module

5.18.6.15 Replacing ‘os.popen()’, ‘os.popen2()’, ‘os.popen3()’
..............................................................

     (child_stdin, child_stdout) = os.popen2(cmd, mode, bufsize)
     ==>
     p = Popen(cmd, shell=True, bufsize=bufsize,
               stdin=PIPE, stdout=PIPE, close_fds=True)
     (child_stdin, child_stdout) = (p.stdin, p.stdout)

     (child_stdin,
      child_stdout,
      child_stderr) = os.popen3(cmd, mode, bufsize)
     ==>
     p = Popen(cmd, shell=True, bufsize=bufsize,
               stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True)
     (child_stdin,
      child_stdout,
      child_stderr) = (p.stdin, p.stdout, p.stderr)

     (child_stdin, child_stdout_and_stderr) = os.popen4(cmd, mode, bufsize)
     ==>
     p = Popen(cmd, shell=True, bufsize=bufsize,
               stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True)
     (child_stdin, child_stdout_and_stderr) = (p.stdin, p.stdout)

Return code handling translates as follows:

     pipe = os.popen(cmd, 'w')
     ...
     rc = pipe.close()
     if rc is not None and rc >> 8:
         print("There were some errors")
     ==>
     process = Popen(cmd, stdin=PIPE)
     ...
     process.stdin.close()
     if process.wait() != 0:
         print("There were some errors")


File: python.info,  Node: Replacing functions from the popen2 module,  Prev: Replacing os popen os popen2 os popen3,  Up: Replacing Older Functions with the subprocess Module

5.18.6.16 Replacing functions from the ‘popen2’ module
......................................................

     Note: If the cmd argument to popen2 functions is a string, the
     command is executed through /bin/sh.  If it is a list, the command
     is directly executed.

     (child_stdout, child_stdin) = popen2.popen2("somestring", bufsize, mode)
     ==>
     p = Popen("somestring", shell=True, bufsize=bufsize,
               stdin=PIPE, stdout=PIPE, close_fds=True)
     (child_stdout, child_stdin) = (p.stdout, p.stdin)

     (child_stdout, child_stdin) = popen2.popen2(["mycmd", "myarg"], bufsize, mode)
     ==>
     p = Popen(["mycmd", "myarg"], bufsize=bufsize,
               stdin=PIPE, stdout=PIPE, close_fds=True)
     (child_stdout, child_stdin) = (p.stdout, p.stdin)

‘popen2.Popen3’ and ‘popen2.Popen4’ basically work as *note
subprocess.Popen: 199, except that:

   * *note Popen: 199. raises an exception if the execution fails.

   * The 'capturestderr' argument is replaced with the 'stderr'
     argument.

   * ‘stdin=PIPE’ and ‘stdout=PIPE’ must be specified.

   * popen2 closes all file descriptors by default, but you have to
     specify ‘close_fds=True’ with *note Popen: 199. to guarantee this
     behavior on all platforms or past Python versions.


File: python.info,  Node: Legacy Shell Invocation Functions,  Next: Notes<2>,  Prev: Replacing Older Functions with the subprocess Module,  Up: subprocess — Subprocess management

5.18.6.17 Legacy Shell Invocation Functions
...........................................

This module also provides the following legacy functions from the 2.x
‘commands’ module.  These operations implicitly invoke the system shell
and none of the guarantees described above regarding security and
exception handling consistency are valid for these functions.

 -- Function: subprocess.getstatusoutput (cmd, *, encoding=None,
          errors=None)

     Return ‘(exitcode, output)’ of executing 'cmd' in a shell.

     Execute the string 'cmd' in a shell with *note check_output(): ffb.
     and return a 2-tuple ‘(exitcode, output)’.  'encoding' and 'errors'
     are used to decode output; see the notes on *note Frequently Used
     Arguments: 33fc. for more details.

     A trailing newline is stripped from the output.  The exit code for
     the command can be interpreted as the return code of subprocess.
     Example:

          >>> subprocess.getstatusoutput('ls /bin/ls')
          (0, '/bin/ls')
          >>> subprocess.getstatusoutput('cat /bin/junk')
          (1, 'cat: /bin/junk: No such file or directory')
          >>> subprocess.getstatusoutput('/bin/junk')
          (127, 'sh: /bin/junk: not found')
          >>> subprocess.getstatusoutput('/bin/kill $$')
          (-15, '')

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.3.4: Windows support was added.

     The function now returns (exitcode, output) instead of (status,
     output) as it did in Python 3.3.3 and earlier.  exitcode has the
     same value as *note returncode: aa1.

     Changed in version 3.11: Added the 'encoding' and 'errors'
     parameters.

 -- Function: subprocess.getoutput (cmd, *, encoding=None, errors=None)

     Return output (stdout and stderr) of executing 'cmd' in a shell.

     Like *note getstatusoutput(): ffd, except the exit code is ignored
     and the return value is a string containing the command’s output.
     Example:

          >>> subprocess.getoutput('ls /bin/ls')
          '/bin/ls'

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.3.4: Windows support added

     Changed in version 3.11: Added the 'encoding' and 'errors'
     parameters.


File: python.info,  Node: Notes<2>,  Prev: Legacy Shell Invocation Functions,  Up: subprocess — Subprocess management

5.18.6.18 Notes
...............

* Menu:

* Timeout Behavior::
* Converting an argument sequence to a string on Windows::
* Disabling use of vfork() or posix_spawn(): Disabling use of vfork or posix_spawn.


File: python.info,  Node: Timeout Behavior,  Next: Converting an argument sequence to a string on Windows,  Up: Notes<2>

5.18.6.19 Timeout Behavior
..........................

When using the ‘timeout’ parameter in functions like *note run(): ba4,
*note Popen.wait(): d0b, or *note Popen.communicate(): 15f2, users
should be aware of the following behaviors:

  1. 'Process Creation Delay': The initial process creation itself
     cannot be interrupted on many platform APIs.  This means that even
     when specifying a timeout, you are not guaranteed to see a timeout
     exception until at least after however long process creation takes.

  2. 'Extremely Small Timeout Values': Setting very small timeout values
     (such as a few milliseconds) may result in almost immediate *note
     TimeoutExpired: 15f3. exceptions because process creation and
     system scheduling inherently require time.


File: python.info,  Node: Converting an argument sequence to a string on Windows,  Next: Disabling use of vfork or posix_spawn,  Prev: Timeout Behavior,  Up: Notes<2>

5.18.6.20 Converting an argument sequence to a string on Windows
................................................................

On Windows, an 'args' sequence is converted to a string that can be
parsed using the following rules (which correspond to the rules used by
the MS C runtime):

  1. Arguments are delimited by white space, which is either a space or
     a tab.

  2. A string surrounded by double quotation marks is interpreted as a
     single argument, regardless of white space contained within.  A
     quoted string can be embedded in an argument.

  3. A double quotation mark preceded by a backslash is interpreted as a
     literal double quotation mark.

  4. Backslashes are interpreted literally, unless they immediately
     precede a double quotation mark.

  5. If backslashes immediately precede a double quotation mark, every
     pair of backslashes is interpreted as a literal backslash.  If the
     number of backslashes is odd, the last backslash escapes the next
     double quotation mark as described in rule 3.

See also
........

*note shlex: c4.

     Module which provides function to parse and escape command lines.


File: python.info,  Node: Disabling use of vfork or posix_spawn,  Prev: Converting an argument sequence to a string on Windows,  Up: Notes<2>

5.18.6.21 Disabling use of ‘vfork()’ or ‘posix_spawn()’
.......................................................

On Linux, ‘subprocess’ defaults to using the ‘vfork()’ system call
internally when it is safe to do so rather than ‘fork()’.  This greatly
improves performance.

If you ever encounter a presumed highly unusual situation where you need
to prevent ‘vfork()’ from being used by Python, you can set the
‘subprocess._USE_VFORK’ attribute to a false value.

     subprocess._USE_VFORK = False  # See CPython issue gh-NNNNNN.

Setting this has no impact on use of ‘posix_spawn()’ which could use
‘vfork()’ internally within its libc implementation.  There is a similar
‘subprocess._USE_POSIX_SPAWN’ attribute if you need to prevent use of
that.

     subprocess._USE_POSIX_SPAWN = False  # See CPython issue gh-NNNNNN.

It is safe to set these to false on any Python version.  They will have
no effect on older versions when unsupported.  Do not assume the
attributes are available to read.  Despite their names, a true value
does not indicate that the corresponding function will be used, only
that it may be.

Please file issues any time you have to use these private knobs with a
way to reproduce the issue you were seeing.  Link to that issue from a
comment in your code.

Added in version 3.8: ‘_USE_POSIX_SPAWN’

Added in version 3.11: ‘_USE_VFORK’


File: python.info,  Node: sched — Event scheduler,  Next: queue — A synchronized queue class,  Prev: subprocess — Subprocess management,  Up: Concurrent Execution

5.18.7 ‘sched’ — Event scheduler
--------------------------------

'Source code:' Lib/sched.py(1)

__________________________________________________________________

The ‘sched’ module defines a class which implements a general purpose
event scheduler:

 -- Class: sched.scheduler (timefunc=time.monotonic,
          delayfunc=time.sleep)

     The ‘scheduler’ class defines a generic interface to scheduling
     events.  It needs two functions to actually deal with the “outside
     world” — 'timefunc' should be callable without arguments, and
     return a number (the “time”, in any units whatsoever).  The
     'delayfunc' function should be callable with one argument,
     compatible with the output of 'timefunc', and should delay that
     many time units.  'delayfunc' will also be called with the argument
     ‘0’ after each event is run to allow other threads an opportunity
     to run in multi-threaded applications.

     Changed in version 3.3: 'timefunc' and 'delayfunc' parameters are
     optional.

     Changed in version 3.3: ‘scheduler’ class can be safely used in
     multi-threaded environments.

Example:

     >>> import sched, time
     >>> s = sched.scheduler(time.time, time.sleep)
     >>> def print_time(a='default'):
     ...     print("From print_time", time.time(), a)
     ...
     >>> def print_some_times():
     ...     print(time.time())
     ...     s.enter(10, 1, print_time)
     ...     s.enter(5, 2, print_time, argument=('positional',))
     ...     # despite having higher priority, 'keyword' runs after 'positional' as enter() is relative
     ...     s.enter(5, 1, print_time, kwargs={'a': 'keyword'})
     ...     s.enterabs(1_650_000_000, 10, print_time, argument=("first enterabs",))
     ...     s.enterabs(1_650_000_000, 5, print_time, argument=("second enterabs",))
     ...     s.run()
     ...     print(time.time())
     ...
     >>> print_some_times()
     1652342830.3640375
     From print_time 1652342830.3642538 second enterabs
     From print_time 1652342830.3643398 first enterabs
     From print_time 1652342835.3694863 positional
     From print_time 1652342835.3696074 keyword
     From print_time 1652342840.369612 default
     1652342840.3697174

* Menu:

* Scheduler Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/sched.py


File: python.info,  Node: Scheduler Objects,  Up: sched — Event scheduler

5.18.7.1 Scheduler Objects
..........................

*note scheduler: 116b. instances have the following methods and
attributes:

 -- Method: scheduler.enterabs (time, priority, action, argument=(),
          kwargs={})

     Schedule a new event.  The 'time' argument should be a numeric type
     compatible with the return value of the 'timefunc' function passed
     to the constructor.  Events scheduled for the same 'time' will be
     executed in the order of their 'priority'.  A lower number
     represents a higher priority.

     Executing the event means executing ‘action(*argument, **kwargs)’.
     'argument' is a sequence holding the positional arguments for
     'action'.  'kwargs' is a dictionary holding the keyword arguments
     for 'action'.

     Return value is an event which may be used for later cancellation
     of the event (see *note cancel(): 1aa2.).

     Changed in version 3.3: 'argument' parameter is optional.

     Changed in version 3.3: 'kwargs' parameter was added.

 -- Method: scheduler.enter (delay, priority, action, argument=(),
          kwargs={})

     Schedule an event for 'delay' more time units.  Other than the
     relative time, the other arguments, the effect and the return value
     are the same as those for *note enterabs(): 116d.

     Changed in version 3.3: 'argument' parameter is optional.

     Changed in version 3.3: 'kwargs' parameter was added.

 -- Method: scheduler.cancel (event)

     Remove the event from the queue.  If 'event' is not an event
     currently in the queue, this method will raise a *note ValueError:
     202.

 -- Method: scheduler.empty ()

     Return ‘True’ if the event queue is empty.

 -- Method: scheduler.run (blocking=True)

     Run all scheduled events.  This method will wait (using the
     'delayfunc' function passed to the constructor) for the next event,
     then execute it and so on until there are no more scheduled events.

     If 'blocking' is false executes the scheduled events due to expire
     soonest (if any) and then return the deadline of the next scheduled
     call in the scheduler (if any).

     Either 'action' or 'delayfunc' can raise an exception.  In either
     case, the scheduler will maintain a consistent state and propagate
     the exception.  If an exception is raised by 'action', the event
     will not be attempted in future calls to ‘run()’.

     If a sequence of events takes longer to run than the time available
     before the next event, the scheduler will simply fall behind.  No
     events will be dropped; the calling code is responsible for
     canceling events which are no longer pertinent.

     Changed in version 3.3: 'blocking' parameter was added.

 -- Attribute: scheduler.queue

     Read-only attribute returning a list of upcoming events in the
     order they will be run.  Each event is shown as a *note named
     tuple: 651. with the following fields: time, priority, action,
     argument, kwargs.


File: python.info,  Node: queue — A synchronized queue class,  Next: contextvars — Context Variables,  Prev: sched — Event scheduler,  Up: Concurrent Execution

5.18.8 ‘queue’ — A synchronized queue class
-------------------------------------------

'Source code:' Lib/queue.py(1)

__________________________________________________________________

The ‘queue’ module implements multi-producer, multi-consumer queues.  It
is especially useful in threaded programming when information must be
exchanged safely between multiple threads.  The *note Queue: 13e1. class
in this module implements all the required locking semantics.

The module implements three types of queue, which differ only in the
order in which the entries are retrieved.  In a FIFO queue, the first
tasks added are the first retrieved.  In a LIFO queue, the most recently
added entry is the first retrieved (operating like a stack).  With a
priority queue, the entries are kept sorted (using the *note heapq: 69.
module) and the lowest valued entry is retrieved first.

Internally, those three types of queues use locks to temporarily block
competing threads; however, they are not designed to handle reentrancy
within a thread.

In addition, the module implements a “simple” FIFO queue type, *note
SimpleQueue: b86, whose specific implementation provides additional
guarantees in exchange for the smaller functionality.

The ‘queue’ module defines the following classes and exceptions:

 -- Class: queue.Queue (maxsize=0)

     Constructor for a FIFO queue.  'maxsize' is an integer that sets
     the upperbound limit on the number of items that can be placed in
     the queue.  Insertion will block once this size has been reached,
     until queue items are consumed.  If 'maxsize' is less than or equal
     to zero, the queue size is infinite.

 -- Class: queue.LifoQueue (maxsize=0)

     Constructor for a LIFO queue.  'maxsize' is an integer that sets
     the upperbound limit on the number of items that can be placed in
     the queue.  Insertion will block once this size has been reached,
     until queue items are consumed.  If 'maxsize' is less than or equal
     to zero, the queue size is infinite.

 -- Class: queue.PriorityQueue (maxsize=0)

     Constructor for a priority queue.  'maxsize' is an integer that
     sets the upperbound limit on the number of items that can be placed
     in the queue.  Insertion will block once this size has been
     reached, until queue items are consumed.  If 'maxsize' is less than
     or equal to zero, the queue size is infinite.

     The lowest valued entries are retrieved first (the lowest valued
     entry is the one that would be returned by ‘min(entries)’).  A
     typical pattern for entries is a tuple in the form:
     ‘(priority_number, data)’.

     If the 'data' elements are not comparable, the data can be wrapped
     in a class that ignores the data item and only compares the
     priority number:

          from dataclasses import dataclass, field
          from typing import Any

          @dataclass(order=True)
          class PrioritizedItem:
              priority: int
              item: Any=field(compare=False)

 -- Class: queue.SimpleQueue

     Constructor for an unbounded FIFO queue.  Simple queues lack
     advanced functionality such as task tracking.

     Added in version 3.7.

 -- Exception: queue.Empty

     Exception raised when non-blocking *note get(): 2ec1. (or *note
     get_nowait(): 3456.) is called on a *note Queue: 13e1. object which
     is empty.

 -- Exception: queue.Full

     Exception raised when non-blocking *note put(): 3457. (or *note
     put_nowait(): 2ec0.) is called on a *note Queue: 13e1. object which
     is full.

 -- Exception: queue.ShutDown

     Exception raised when *note put(): 3457. or *note get(): 2ec1. is
     called on a *note Queue: 13e1. object which has been shut down.

     Added in version 3.13.

* Menu:

* Queue Objects::
* SimpleQueue Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/queue.py


File: python.info,  Node: Queue Objects,  Next: SimpleQueue Objects,  Up: queue — A synchronized queue class

5.18.8.1 Queue Objects
......................

Queue objects (*note Queue: 13e1, *note LifoQueue: 240e, or *note
PriorityQueue: 240f.) provide the public methods described below.

 -- Method: Queue.qsize ()

     Return the approximate size of the queue.  Note, qsize() > 0
     doesn’t guarantee that a subsequent get() will not block, nor will
     qsize() < maxsize guarantee that put() will not block.

 -- Method: Queue.empty ()

     Return ‘True’ if the queue is empty, ‘False’ otherwise.  If empty()
     returns ‘True’ it doesn’t guarantee that a subsequent call to put()
     will not block.  Similarly, if empty() returns ‘False’ it doesn’t
     guarantee that a subsequent call to get() will not block.

 -- Method: Queue.full ()

     Return ‘True’ if the queue is full, ‘False’ otherwise.  If full()
     returns ‘True’ it doesn’t guarantee that a subsequent call to get()
     will not block.  Similarly, if full() returns ‘False’ it doesn’t
     guarantee that a subsequent call to put() will not block.

 -- Method: Queue.put (item, block=True, timeout=None)

     Put 'item' into the queue.  If optional args 'block' is true and
     'timeout' is ‘None’ (the default), block if necessary until a free
     slot is available.  If 'timeout' is a positive number, it blocks at
     most 'timeout' seconds and raises the *note Full: 3369. exception
     if no free slot was available within that time.  Otherwise ('block'
     is false), put an item on the queue if a free slot is immediately
     available, else raise the ‘Full’ exception ('timeout' is ignored in
     that case).

     Raises *note ShutDown: 23b. if the queue has been shut down.

 -- Method: Queue.put_nowait (item)

     Equivalent to ‘put(item, block=False)’.

 -- Method: Queue.get (block=True, timeout=None)

     Remove and return an item from the queue.  If optional args 'block'
     is true and 'timeout' is ‘None’ (the default), block if necessary
     until an item is available.  If 'timeout' is a positive number, it
     blocks at most 'timeout' seconds and raises the *note Empty: 3368.
     exception if no item was available within that time.  Otherwise
     ('block' is false), return an item if one is immediately available,
     else raise the ‘Empty’ exception ('timeout' is ignored in that
     case).

     Prior to 3.0 on POSIX systems, and for all versions on Windows, if
     'block' is true and 'timeout' is ‘None’, this operation goes into
     an uninterruptible wait on an underlying lock.  This means that no
     exceptions can occur, and in particular a SIGINT will not trigger a
     *note KeyboardInterrupt: 9dc.

     Raises *note ShutDown: 23b. if the queue has been shut down and is
     empty, or if the queue has been shut down immediately.

 -- Method: Queue.get_nowait ()

     Equivalent to ‘get(False)’.

Two methods are offered to support tracking whether enqueued tasks have
been fully processed by daemon consumer threads.

 -- Method: Queue.task_done ()

     Indicate that a formerly enqueued task is complete.  Used by queue
     consumer threads.  For each *note get(): 2ec1. used to fetch a
     task, a subsequent call to ‘task_done()’ tells the queue that the
     processing on the task is complete.

     If a *note join(): 3365. is currently blocking, it will resume when
     all items have been processed (meaning that a ‘task_done()’ call
     was received for every item that had been *note put(): 3457. into
     the queue).

     Raises a *note ValueError: 202. if called more times than there
     were items placed in the queue.

 -- Method: Queue.join ()

     Blocks until all items in the queue have been gotten and processed.

     The count of unfinished tasks goes up whenever an item is added to
     the queue.  The count goes down whenever a consumer thread calls
     *note task_done(): 3364. to indicate that the item was retrieved
     and all work on it is complete.  When the count of unfinished tasks
     drops to zero, ‘join()’ unblocks.

* Menu:

* Waiting for task completion::
* Terminating queues::


File: python.info,  Node: Waiting for task completion,  Next: Terminating queues,  Up: Queue Objects

5.18.8.2 Waiting for task completion
....................................

Example of how to wait for enqueued tasks to be completed:

     import threading
     import queue

     q = queue.Queue()

     def worker():
         while True:
             item = q.get()
             print(f'Working on {item}')
             print(f'Finished {item}')
             q.task_done()

     # Turn-on the worker thread.
     threading.Thread(target=worker, daemon=True).start()

     # Send thirty task requests to the worker.
     for item in range(30):
         q.put(item)

     # Block until all tasks are done.
     q.join()
     print('All work completed')


File: python.info,  Node: Terminating queues,  Prev: Waiting for task completion,  Up: Queue Objects

5.18.8.3 Terminating queues
...........................

When no longer needed, *note Queue: 13e1. objects can be wound down
until empty or terminated immediately with a hard shutdown.

 -- Method: Queue.shutdown (immediate=False)

     Put a *note Queue: 13e1. instance into a shutdown mode.

     The queue can no longer grow.  Future calls to *note put(): 3457.
     raise *note ShutDown: 23b.  Currently blocked callers of ‘put()’
     will be unblocked and will raise ‘ShutDown’ in the formerly blocked
     thread.

     If 'immediate' is false (the default), the queue can be wound down
     normally with *note get(): 2ec1. calls to extract tasks that have
     already been loaded.

     And if *note task_done(): 3364. is called for each remaining task,
     a pending *note join(): 3365. will be unblocked normally.

     Once the queue is empty, future calls to *note get(): 2ec1. will
     raise *note ShutDown: 23b.

     If 'immediate' is true, the queue is terminated immediately.  The
     queue is drained to be completely empty and the count of unfinished
     tasks is reduced by the number of tasks drained.  If unfinished
     tasks is zero, callers of *note join(): 3365. are unblocked.  Also,
     blocked callers of *note get(): 2ec1. are unblocked and will raise
     *note ShutDown: 23b. because the queue is empty.

     Use caution when using *note join(): 3365. with 'immediate' set to
     true.  This unblocks the join even when no work has been done on
     the tasks, violating the usual invariant for joining a queue.

     Added in version 3.13.


File: python.info,  Node: SimpleQueue Objects,  Prev: Queue Objects,  Up: queue — A synchronized queue class

5.18.8.4 SimpleQueue Objects
............................

*note SimpleQueue: b86. objects provide the public methods described
below.

 -- Method: SimpleQueue.qsize ()

     Return the approximate size of the queue.  Note, qsize() > 0
     doesn’t guarantee that a subsequent get() will not block.

 -- Method: SimpleQueue.empty ()

     Return ‘True’ if the queue is empty, ‘False’ otherwise.  If empty()
     returns ‘False’ it doesn’t guarantee that a subsequent call to
     get() will not block.

 -- Method: SimpleQueue.put (item, block=True, timeout=None)

     Put 'item' into the queue.  The method never blocks and always
     succeeds (except for potential low-level errors such as failure to
     allocate memory).  The optional args 'block' and 'timeout' are
     ignored and only provided for compatibility with *note Queue.put():
     3457.

     'CPython implementation detail:' This method has a C implementation
     which is reentrant.  That is, a ‘put()’ or ‘get()’ call can be
     interrupted by another ‘put()’ call in the same thread without
     deadlocking or corrupting internal state inside the queue.  This
     makes it appropriate for use in destructors such as ‘__del__’
     methods or *note weakref: 114. callbacks.

 -- Method: SimpleQueue.put_nowait (item)

     Equivalent to ‘put(item, block=False)’, provided for compatibility
     with *note Queue.put_nowait(): 2ec0.

 -- Method: SimpleQueue.get (block=True, timeout=None)

     Remove and return an item from the queue.  If optional args 'block'
     is true and 'timeout' is ‘None’ (the default), block if necessary
     until an item is available.  If 'timeout' is a positive number, it
     blocks at most 'timeout' seconds and raises the *note Empty: 3368.
     exception if no item was available within that time.  Otherwise
     ('block' is false), return an item if one is immediately available,
     else raise the ‘Empty’ exception ('timeout' is ignored in that
     case).

 -- Method: SimpleQueue.get_nowait ()

     Equivalent to ‘get(False)’.

See also
........

Class *note multiprocessing.Queue: 192f.

     A queue class for use in a multi-processing (rather than
     multi-threading) context.

*note collections.deque: 5df. is an alternative implementation of
unbounded queues with fast atomic *note append(): 26ca. and *note
popleft(): 26d0. operations that do not require locking and also support
indexing.


File: python.info,  Node: contextvars — Context Variables,  Next: _thread — Low-level threading API,  Prev: queue — A synchronized queue class,  Up: Concurrent Execution

5.18.9 ‘contextvars’ — Context Variables
----------------------------------------

__________________________________________________________________

This module provides APIs to manage, store, and access context-local
state.  The *note ContextVar: 1662. class is used to declare and work
with 'Context Variables'.  The *note copy_context(): 3469. function and
the *note Context: 15dd. class should be used to manage the current
context in asynchronous frameworks.

Context managers that have state should use Context Variables instead of
*note threading.local(): 1650. to prevent their state from bleeding to
other code unexpectedly, when used in concurrent code.

See also PEP 567(1) for additional details.

Added in version 3.7.

* Menu:

* Context Variables::
* Manual Context Management::
* asyncio support::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0567/


File: python.info,  Node: Context Variables,  Next: Manual Context Management,  Up: contextvars — Context Variables

5.18.9.1 Context Variables
..........................

 -- Class: contextvars.ContextVar (name[, *, default])

     This class is used to declare a new Context Variable, e.g.:

          var: ContextVar[int] = ContextVar('var', default=42)

     The required 'name' parameter is used for introspection and debug
     purposes.

     The optional keyword-only 'default' parameter is returned by *note
     ContextVar.get(): 346b. when no value for the variable is found in
     the current context.

     'Important:' Context Variables should be created at the top module
     level and never in closures.  *note Context: 15dd. objects hold
     strong references to context variables which prevents context
     variables from being properly garbage collected.

      -- Attribute: name

          The name of the variable.  This is a read-only property.

          Added in version 3.7.1.

      -- Method: get ([default])

          Return a value for the context variable for the current
          context.

          If there is no value for the variable in the current context,
          the method will:

             * return the value of the 'default' argument of the method,
               if provided; or

             * return the default value for the context variable, if it
               was created with one; or

             * raise a *note LookupError: 238a.

      -- Method: set (value)

          Call to set a new value for the context variable in the
          current context.

          The required 'value' argument is the new value for the context
          variable.

          Returns a *note Token: 346d. object that can be used to
          restore the variable to its previous value via the *note
          ContextVar.reset(): 346e. method.

      -- Method: reset (token)

          Reset the context variable to the value it had before the
          *note ContextVar.set(): 15de. that created the 'token' was
          used.

          For example:

               var = ContextVar('var')

               token = var.set('new value')
               # code that uses 'var'; var.get() returns 'new value'.
               var.reset(token)

               # After the reset call the var has no value again, so
               # var.get() would raise a LookupError.

          The same 'token' cannot be used twice.

 -- Class: contextvars.Token

     'Token' objects are returned by the *note ContextVar.set(): 15de.
     method.  They can be passed to the *note ContextVar.reset(): 346e.
     method to revert the value of the variable to what it was before
     the corresponding 'set'.  A single token cannot reset a context
     variable more than once.

      -- Attribute: var

          A read-only property.  Points to the *note ContextVar: 1662.
          object that created the token.

      -- Attribute: old_value

          A read-only property.  Set to the value the variable had
          before the *note ContextVar.set(): 15de. method call that
          created the token.  It points to *note Token.MISSING: 3471. if
          the variable was not set before the call.

      -- Attribute: MISSING

          A marker object used by *note Token.old_value: 3470.


File: python.info,  Node: Manual Context Management,  Next: asyncio support,  Prev: Context Variables,  Up: contextvars — Context Variables

5.18.9.2 Manual Context Management
..................................

 -- Function: contextvars.copy_context ()

     Returns a copy of the current *note Context: 15dd. object.

     The following snippet gets a copy of the current context and prints
     all variables and their values that are set in it:

          ctx: Context = copy_context()
          print(list(ctx.items()))

     The function has an 'O'(1) complexity, i.e.  works equally fast for
     contexts with a few context variables and for contexts that have a
     lot of them.

 -- Class: contextvars.Context

     A mapping of *note ContextVars: 1662. to their values.

     ‘Context()’ creates an empty context with no values in it.  To get
     a copy of the current context use the *note copy_context(): 3469.
     function.

     Each thread has its own effective stack of ‘Context’ objects.  The
     *note current context: 16b5. is the ‘Context’ object at the top of
     the current thread’s stack.  All ‘Context’ objects in the stacks
     are considered to be 'entered'.

     'Entering' a context, which can be done by calling its *note run():
     1711. method, makes the context the current context by pushing it
     onto the top of the current thread’s context stack.

     'Exiting' from the current context, which can be done by returning
     from the callback passed to the *note run(): 1711. method, restores
     the current context to what it was before the context was entered
     by popping the context off the top of the context stack.

     Since each thread has its own context stack, *note ContextVar:
     1662. objects behave in a similar fashion to *note
     threading.local(): 1650. when values are assigned in different
     threads.

     Attempting to enter an already entered context, including contexts
     entered in other threads, raises a *note RuntimeError: 195.

     After exiting a context, it can later be re-entered (from any
     thread).

     Any changes to *note ContextVar: 1662. values via the *note
     ContextVar.set(): 15de. method are recorded in the current context.
     The *note ContextVar.get(): 346b. method returns the value
     associated with the current context.  Exiting a context effectively
     reverts any changes made to context variables while the context was
     entered (if needed, the values can be restored by re-entering the
     context).

     Context implements the *note collections.abc.Mapping: 8d3.
     interface.

      -- Method: run (callable, *args, **kwargs)

          Enters the Context, executes ‘callable(*args, **kwargs)’, then
          exits the Context.  Returns 'callable'’s return value, or
          propagates an exception if one occurred.

          Example:

               import contextvars

               var = contextvars.ContextVar('var')
               var.set('spam')
               print(var.get())  # 'spam'

               ctx = contextvars.copy_context()

               def main():
                   # 'var' was set to 'spam' before
                   # calling 'copy_context()' and 'ctx.run(main)', so:
                   print(var.get())  # 'spam'
                   print(ctx[var])  # 'spam'

                   var.set('ham')

                   # Now, after setting 'var' to 'ham':
                   print(var.get())  # 'ham'
                   print(ctx[var])  # 'ham'

               # Any changes that the 'main' function makes to 'var'
               # will be contained in 'ctx'.
               ctx.run(main)

               # The 'main()' function was run in the 'ctx' context,
               # so changes to 'var' are contained in it:
               print(ctx[var])  # 'ham'

               # However, outside of 'ctx', 'var' is still set to 'spam':
               print(var.get())  # 'spam'

      -- Method: copy ()

          Return a shallow copy of the context object.

      -- Describe: var in context

          Return ‘True’ if the 'context' has a value for 'var' set;
          return ‘False’ otherwise.

      -- Describe: context[var]

          Return the value of the 'var' *note ContextVar: 1662.
          variable.  If the variable is not set in the context object, a
          *note KeyError: 345. is raised.

      -- Method: get (var[, default])

          Return the value for 'var' if 'var' has the value in the
          context object.  Return 'default' otherwise.  If 'default' is
          not given, return ‘None’.

      -- Describe: iter(context)

          Return an iterator over the variables stored in the context
          object.

      -- Describe: len(proxy)

          Return the number of variables set in the context object.

      -- Method: keys ()

          Return a list of all variables in the context object.

      -- Method: values ()

          Return a list of all variables’ values in the context object.

      -- Method: items ()

          Return a list of 2-tuples containing all variables and their
          values in the context object.


File: python.info,  Node: asyncio support,  Prev: Manual Context Management,  Up: contextvars — Context Variables

5.18.9.3 asyncio support
........................

Context variables are natively supported in *note asyncio: a. and are
ready to be used without any extra configuration.  For example, here is
a simple echo server, that uses a context variable to make the address
of a remote client available in the Task that handles that client:

     import asyncio
     import contextvars

     client_addr_var = contextvars.ContextVar('client_addr')

     def render_goodbye():
         # The address of the currently handled client can be accessed
         # without passing it explicitly to this function.

         client_addr = client_addr_var.get()
         return f'Good bye, client @ {client_addr}\r\n'.encode()

     async def handle_request(reader, writer):
         addr = writer.transport.get_extra_info('socket').getpeername()
         client_addr_var.set(addr)

         # In any code that we call is now possible to get
         # client's address by calling 'client_addr_var.get()'.

         while True:
             line = await reader.readline()
             print(line)
             if not line.strip():
                 break

         writer.write(b'HTTP/1.1 200 OK\r\n')  # status line
         writer.write(b'\r\n')  # headers
         writer.write(render_goodbye())  # body
         writer.close()

     async def main():
         srv = await asyncio.start_server(
             handle_request, '127.0.0.1', 8081)

         async with srv:
             await srv.serve_forever()

     asyncio.run(main())

     # To test it you can use telnet or curl:
     #     telnet 127.0.0.1 8081
     #     curl 127.0.0.1:8081

The following are support modules for some of the above services:


File: python.info,  Node: _thread — Low-level threading API,  Prev: contextvars — Context Variables,  Up: Concurrent Execution

5.18.10 ‘_thread’ — Low-level threading API
-------------------------------------------

__________________________________________________________________

This module provides low-level primitives for working with multiple
threads (also called 'light-weight processes' or 'tasks') — multiple
threads of control sharing their global data space.  For
synchronization, simple locks (also called 'mutexes' or 'binary
semaphores') are provided.  The *note threading: ed. module provides an
easier to use and higher-level threading API built on top of this
module.

Changed in version 3.7: This module used to be optional, it is now
always available.

This module defines the following constants and functions:

 -- Exception: _thread.error

     Raised on thread-specific errors.

     Changed in version 3.3: This is now a synonym of the built-in *note
     RuntimeError: 195.

 -- Data: _thread.LockType

     This is the type of lock objects.

 -- Function: _thread.start_new_thread (function, args[, kwargs])

     Start a new thread and return its identifier.  The thread executes
     the function 'function' with the argument list 'args' (which must
     be a tuple).  The optional 'kwargs' argument specifies a dictionary
     of keyword arguments.

     When the function returns, the thread silently exits.

     When the function terminates with an unhandled exception, *note
     sys.unraisablehook(): 1f7. is called to handle the exception.  The
     'object' attribute of the hook argument is 'function'.  By default,
     a stack trace is printed and then the thread exits (but other
     threads continue to run).

     When the function raises a *note SystemExit: d69. exception, it is
     silently ignored.

     Raises an *note auditing event: 1a15. ‘_thread.start_new_thread’
     with arguments ‘function’, ‘args’, ‘kwargs’.

     Changed in version 3.8: *note sys.unraisablehook(): 1f7. is now
     used to handle unhandled exceptions.

 -- Function: _thread.interrupt_main (signum=signal.SIGINT, /)

     Simulate the effect of a signal arriving in the main thread.  A
     thread can use this function to interrupt the main thread, though
     there is no guarantee that the interruption will happen
     immediately.

     If given, 'signum' is the number of the signal to simulate.  If
     'signum' is not given, *note signal.SIGINT: 84a. is simulated.

     If the given signal isn’t handled by Python (it was set to *note
     signal.SIG_DFL: 1957. or *note signal.SIG_IGN: 1956.), this
     function does nothing.

     Changed in version 3.10: The 'signum' argument is added to
     customize the signal number.

          Note: This does not emit the corresponding signal but
          schedules a call to the associated handler (if it exists).  If
          you want to truly emit the signal, use *note
          signal.raise_signal(): 1935.

 -- Function: _thread.exit ()

     Raise the *note SystemExit: d69. exception.  When not caught, this
     will cause the thread to exit silently.

 -- Function: _thread.allocate_lock ()

     Return a new lock object.  Methods of locks are described below.
     The lock is initially unlocked.

 -- Function: _thread.get_ident ()

     Return the ‘thread identifier’ of the current thread.  This is a
     nonzero integer.  Its value has no direct meaning; it is intended
     as a magic cookie to be used e.g.  to index a dictionary of
     thread-specific data.  Thread identifiers may be recycled when a
     thread exits and another thread is created.

 -- Function: _thread.get_native_id ()

     Return the native integral Thread ID of the current thread assigned
     by the kernel.  This is a non-negative integer.  Its value may be
     used to uniquely identify this particular thread system-wide (until
     the thread terminates, after which the value may be recycled by the
     OS).

     *note Availability: 1ef7.: Windows, FreeBSD, Linux, macOS, OpenBSD,
     NetBSD, AIX, DragonFlyBSD, GNU/kFreeBSD.

     Added in version 3.8.

     Changed in version 3.13: Added support for GNU/kFreeBSD.

 -- Function: _thread.stack_size ([size])

     Return the thread stack size used when creating new threads.  The
     optional 'size' argument specifies the stack size to be used for
     subsequently created threads, and must be 0 (use platform or
     configured default) or a positive integer value of at least 32,768
     (32 KiB). If 'size' is not specified, 0 is used.  If changing the
     thread stack size is unsupported, a *note RuntimeError: 195. is
     raised.  If the specified stack size is invalid, a *note
     ValueError: 202. is raised and the stack size is unmodified.  32
     KiB is currently the minimum supported stack size value to
     guarantee sufficient stack space for the interpreter itself.  Note
     that some platforms may have particular restrictions on values for
     the stack size, such as requiring a minimum stack size > 32 KiB or
     requiring allocation in multiples of the system memory page size -
     platform documentation should be referred to for more information
     (4 KiB pages are common; using multiples of 4096 for the stack size
     is the suggested approach in the absence of more specific
     information).

     *note Availability: 1ef7.: Windows, pthreads.

     Unix platforms with POSIX threads support.

 -- Data: _thread.TIMEOUT_MAX

     The maximum value allowed for the 'timeout' parameter of *note
     Lock.acquire: 69b.  Specifying a timeout greater than this value
     will raise an *note OverflowError: 888.

     Added in version 3.2.

Lock objects have the following methods:

 -- Method: lock.acquire (blocking=True, timeout=-1)

     Without any optional argument, this method acquires the lock
     unconditionally, if necessary waiting until it is released by
     another thread (only one thread at a time can acquire a lock —
     that’s their reason for existence).

     If the 'blocking' argument is present, the action depends on its
     value: if it is false, the lock is only acquired if it can be
     acquired immediately without waiting, while if it is true, the lock
     is acquired unconditionally as above.

     If the floating-point 'timeout' argument is present and positive,
     it specifies the maximum wait time in seconds before returning.  A
     negative 'timeout' argument specifies an unbounded wait.  You
     cannot specify a 'timeout' if 'blocking' is false.

     The return value is ‘True’ if the lock is acquired successfully,
     ‘False’ if not.

     Changed in version 3.2: The 'timeout' parameter is new.

     Changed in version 3.2: Lock acquires can now be interrupted by
     signals on POSIX.

 -- Method: lock.release ()

     Releases the lock.  The lock must have been acquired earlier, but
     not necessarily by the same thread.

 -- Method: lock.locked ()

     Return the status of the lock: ‘True’ if it has been acquired by
     some thread, ‘False’ if not.

In addition to these methods, lock objects can also be used via the
*note with: 5d5. statement, e.g.:

     import _thread

     a_lock = _thread.allocate_lock()

     with a_lock:
         print("a_lock is locked while this executes")

'Caveats:'

   * Interrupts always go to the main thread (the *note
     KeyboardInterrupt: 9dc. exception will be received by that thread.)

   * Calling *note sys.exit(): 1394. or raising the *note SystemExit:
     d69. exception is equivalent to calling *note _thread.exit(): 347e.

   * It is platform-dependent whether the *note acquire(): 69b. method
     on a lock can be interrupted (so that the *note KeyboardInterrupt:
     9dc. exception will happen immediately, rather than only after the
     lock has been acquired or the operation has timed out).  It can be
     interrupted on POSIX, but not on Windows.

   * When the main thread exits, it is system defined whether the other
     threads survive.  On most systems, they are killed without
     executing *note try: 6ec. … *note finally: 9d5. clauses or
     executing object destructors.


File: python.info,  Node: Networking and Interprocess Communication,  Next: Internet Data Handling,  Prev: Concurrent Execution,  Up: The Python Standard Library

5.19 Networking and Interprocess Communication
==============================================

The modules described in this chapter provide mechanisms for networking
and inter-processes communication.

Some modules only work for two processes that are on the same machine,
e.g.  *note signal: c6. and *note mmap: 90.  Other modules support
networking protocols that two or more processes can use to communicate
across machines.

The list of modules described in this chapter is:

* Menu:

* asyncio — Asynchronous I/O::
* socket — Low-level networking interface::
* ssl — TLS/SSL wrapper for socket objects::
* select — Waiting for I/O completion::
* selectors — High-level I/O multiplexing::
* signal — Set handlers for asynchronous events::
* mmap — Memory-mapped file support::


File: python.info,  Node: asyncio — Asynchronous I/O,  Next: socket — Low-level networking interface,  Up: Networking and Interprocess Communication

5.19.1 ‘asyncio’ — Asynchronous I/O
-----------------------------------

__________________________________________________________________

Hello World!
............

     import asyncio

     async def main():
         print('Hello ...')
         await asyncio.sleep(1)
         print('... World!')

     asyncio.run(main())

asyncio is a library to write 'concurrent' code using the 'async/await'
syntax.

asyncio is used as a foundation for multiple Python asynchronous
frameworks that provide high-performance network and web-servers,
database connection libraries, distributed task queues, etc.

asyncio is often a perfect fit for IO-bound and high-level 'structured'
network code.

See also
........

*note A Conceptual Overview of asyncio: 348d.

     Explanation of the fundamentals of asyncio.

asyncio provides a set of 'high-level' APIs to:

   * *note run Python coroutines: 348e. concurrently and have full
     control over their execution;

   * perform *note network IO and IPC: 348f.;

   * control *note subprocesses: 3490.;

   * distribute tasks via *note queues: 3491.;

   * *note synchronize: 3492. concurrent code;

Additionally, there are 'low-level' APIs for 'library and framework
developers' to:

   * create and manage *note event loops: da4, which provide
     asynchronous APIs for *note networking: 3493, running *note
     subprocesses: 3494, handling *note OS signals: 3495, etc;

   * implement efficient protocols using *note transports: 3496.;

   * *note bridge: 3497. callback-based libraries and code with
     async/await syntax.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

asyncio REPL
............

You can experiment with an ‘asyncio’ concurrent context in the *note
REPL: 16a.:

     $ python -m asyncio
     asyncio REPL ...
     Use "await" directly instead of "asyncio.run()".
     Type "help", "copyright", "credits" or "license" for more information.
     >>> import asyncio
     >>> await asyncio.sleep(10, result='hello')
     'hello'

This REPL provides limited compatibility with *note PYTHON_BASIC_REPL:
16e.  It is recommended that the default REPL is used for full
functionality and the latest features.

Raises an *note auditing event: 1a15. ‘cpython.run_stdin’ with no
arguments.

Changed in version 3.12.5: (also 3.11.10, 3.10.15, 3.9.20, and 3.8.20)
Emits audit events.

Changed in version 3.13: Uses PyREPL if possible, in which case *note
PYTHONSTARTUP: 1003. is also executed.  Emits audit events.

Reference
.........

* Menu:

* Runners::
* Coroutines and tasks::
* Streams::
* Synchronization Primitives::
* Subprocesses::
* Queues::
* Exceptions: Exceptions<13>.
* Event loop::
* Futures::
* Transports and Protocols::
* Policies::
* Platform Support::
* Extending::
* High-level API Index::
* Low-level API Index::
* Developing with asyncio::


File: python.info,  Node: Runners,  Next: Coroutines and tasks,  Up: asyncio — Asynchronous I/O

5.19.1.1 Runners
................

'Source code:' Lib/asyncio/runners.py(1)

This section outlines high-level asyncio primitives to run asyncio code.

They are built on top of an *note event loop: da4. with the aim to
simplify async code usage for common wide-spread scenarios.

* Menu:

* Running an asyncio Program::
* Runner context manager::
* Handling Keyboard Interruption::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/runners.py


File: python.info,  Node: Running an asyncio Program,  Next: Runner context manager,  Up: Runners

5.19.1.2 Running an asyncio Program
...................................

 -- Function: asyncio.run (coro, *, debug=None, loop_factory=None)

     Execute the *note coroutine: 494. 'coro' and return the result.

     This function runs the passed coroutine, taking care of managing
     the asyncio event loop, 'finalizing asynchronous generators', and
     closing the executor.

     This function cannot be called when another asyncio event loop is
     running in the same thread.

     If 'debug' is ‘True’, the event loop will be run in debug mode.
     ‘False’ disables debug mode explicitly.  ‘None’ is used to respect
     the global *note Debug Mode: 1ef2. settings.

     If 'loop_factory' is not ‘None’, it is used to create a new event
     loop; otherwise *note asyncio.new_event_loop(): 349c. is used.  The
     loop is closed at the end.  This function should be used as a main
     entry point for asyncio programs, and should ideally only be called
     once.  It is recommended to use 'loop_factory' to configure the
     event loop instead of policies.  Passing *note asyncio.EventLoop:
     1806. allows running asyncio without the policy system.

     The executor is given a timeout duration of 5 minutes to shutdown.
     If the executor hasn’t finished within that duration, a warning is
     emitted and the executor is closed.

     Example:

          async def main():
              await asyncio.sleep(1)
              print('hello')

          asyncio.run(main())

     Added in version 3.7.

     Changed in version 3.9: Updated to use *note
     loop.shutdown_default_executor(): 8f0.

     Changed in version 3.10: 'debug' is ‘None’ by default to respect
     the global debug mode settings.

     Changed in version 3.12: Added 'loop_factory' parameter.


File: python.info,  Node: Runner context manager,  Next: Handling Keyboard Interruption,  Prev: Running an asyncio Program,  Up: Runners

5.19.1.3 Runner context manager
...............................

 -- Class: asyncio.Runner (*, debug=None, loop_factory=None)

     A context manager that simplifies 'multiple' async function calls
     in the same context.

     Sometimes several top-level async functions should be called in the
     same *note event loop: da4. and *note contextvars.Context: 15dd.

     If 'debug' is ‘True’, the event loop will be run in debug mode.
     ‘False’ disables debug mode explicitly.  ‘None’ is used to respect
     the global *note Debug Mode: 1ef2. settings.

     'loop_factory' could be used for overriding the loop creation.  It
     is the responsibility of the 'loop_factory' to set the created loop
     as the current one.  By default *note asyncio.new_event_loop():
     349c. is used and set as current event loop with *note
     asyncio.set_event_loop(): 18fa. if 'loop_factory' is ‘None’.

     Basically, *note asyncio.run(): 47f. example can be rewritten with
     the runner usage:

          async def main():
              await asyncio.sleep(1)
              print('hello')

          with asyncio.Runner() as runner:
              runner.run(main())

     Added in version 3.11.

      -- Method: run (coro, *, context=None)

          Run a *note coroutine: 494. 'coro' in the embedded loop.

          Return the coroutine’s result or raise its exception.

          An optional keyword-only 'context' argument allows specifying
          a custom *note contextvars.Context: 15dd. for the 'coro' to
          run in.  The runner’s default context is used if ‘None’.

          This function cannot be called when another asyncio event loop
          is running in the same thread.

      -- Method: close ()

          Close the runner.

          Finalize asynchronous generators, shutdown default executor,
          close the event loop and release embedded *note
          contextvars.Context: 15dd.

      -- Method: get_loop ()

          Return the event loop associated with the runner instance.

          Note: ‘Runner’ uses the lazy initialization strategy, its
          constructor doesn’t initialize underlying low-level
          structures.

          Embedded 'loop' and 'context' are created at the *note with:
          5d5. body entering or the first call of *note run(): 47f. or
          *note get_loop(): 349f.


File: python.info,  Node: Handling Keyboard Interruption,  Prev: Runner context manager,  Up: Runners

5.19.1.4 Handling Keyboard Interruption
.......................................

Added in version 3.11.

When *note signal.SIGINT: 84a. is raised by ‘Ctrl’-‘C’, *note
KeyboardInterrupt: 9dc. exception is raised in the main thread by
default.  However this doesn’t work with *note asyncio: a. because it
can interrupt asyncio internals and can hang the program from exiting.

To mitigate this issue, *note asyncio: a. handles *note signal.SIGINT:
84a. as follows:

  1. *note asyncio.Runner.run(): 17be. installs a custom *note
     signal.SIGINT: 84a. handler before any user code is executed and
     removes it when exiting from the function.

  2. The *note Runner: 603. creates the main task for the passed
     coroutine for its execution.

  3. When *note signal.SIGINT: 84a. is raised by ‘Ctrl’-‘C’, the custom
     signal handler cancels the main task by calling *note
     asyncio.Task.cancel(): 1b7. which raises *note
     asyncio.CancelledError: 1b8. inside the main task.  This causes the
     Python stack to unwind, ‘try/except’ and ‘try/finally’ blocks can
     be used for resource cleanup.  After the main task is cancelled,
     *note asyncio.Runner.run(): 17be. raises *note KeyboardInterrupt:
     9dc.

  4. A user could write a tight loop which cannot be interrupted by
     *note asyncio.Task.cancel(): 1b7, in which case the second
     following ‘Ctrl’-‘C’ immediately raises the *note
     KeyboardInterrupt: 9dc. without cancelling the main task.


File: python.info,  Node: Coroutines and tasks,  Next: Streams,  Prev: Runners,  Up: asyncio — Asynchronous I/O

5.19.1.5 Coroutines and tasks
.............................

This section outlines high-level asyncio APIs to work with coroutines
and Tasks.

* Menu:

* Coroutines: Coroutines<3>.
* Awaitables::
* Creating tasks::
* Task cancellation::
* Task groups::
* Sleeping::
* Running tasks concurrently::
* Eager task factory::
* Shielding from cancellation::
* Timeouts::
* Waiting primitives::
* Running in threads::
* Scheduling from other threads::
* Introspection::
* Task object::


File: python.info,  Node: Coroutines<3>,  Next: Awaitables,  Up: Coroutines and tasks

5.19.1.6 Coroutines
...................

'Source code:' Lib/asyncio/coroutines.py(1)

__________________________________________________________________

*note Coroutines: 494. declared with the async/await syntax is the
preferred way of writing asyncio applications.  For example, the
following snippet of code prints “hello”, waits 1 second, and then
prints “world”:

     >>> import asyncio

     >>> async def main():
     ...     print('hello')
     ...     await asyncio.sleep(1)
     ...     print('world')

     >>> asyncio.run(main())
     hello
     world

Note that simply calling a coroutine will not schedule it to be
executed:

     >>> main()
     <coroutine object main at 0x1053bb7c8>

To actually run a coroutine, asyncio provides the following mechanisms:

   * The *note asyncio.run(): 47f. function to run the top-level entry
     point “main()” function (see the above example.)

   * Awaiting on a coroutine.  The following snippet of code will print
     “hello” after waiting for 1 second, and then print “world” after
     waiting for 'another' 2 seconds:

          import asyncio
          import time

          async def say_after(delay, what):
              await asyncio.sleep(delay)
              print(what)

          async def main():
              print(f"started at {time.strftime('%X')}")

              await say_after(1, 'hello')
              await say_after(2, 'world')

              print(f"finished at {time.strftime('%X')}")

          asyncio.run(main())

     Expected output:

          started at 17:13:52
          hello
          world
          finished at 17:13:55

   * The *note asyncio.create_task(): 1bf. function to run coroutines
     concurrently as asyncio *note Tasks: 1be.

     Let’s modify the above example and run two ‘say_after’ coroutines
     'concurrently':

          async def main():
              task1 = asyncio.create_task(
                  say_after(1, 'hello'))

              task2 = asyncio.create_task(
                  say_after(2, 'world'))

              print(f"started at {time.strftime('%X')}")

              # Wait until both tasks are completed (should take
              # around 2 seconds.)
              await task1
              await task2

              print(f"finished at {time.strftime('%X')}")

     Note that expected output now shows that the snippet runs 1 second
     faster than before:

          started at 17:14:32
          hello
          world
          finished at 17:14:34

   * The *note asyncio.TaskGroup: 1b5. class provides a more modern
     alternative to *note create_task(): 1bf.  Using this API, the last
     example becomes:

          async def main():
              async with asyncio.TaskGroup() as tg:
                  task1 = tg.create_task(
                      say_after(1, 'hello'))

                  task2 = tg.create_task(
                      say_after(2, 'world'))

                  print(f"started at {time.strftime('%X')}")

              # The await is implicit when the context manager exits.

              print(f"finished at {time.strftime('%X')}")

     The timing and output should be the same as for the previous
     version.

     Added in version 3.11: *note asyncio.TaskGroup: 1b5.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/coroutines.py


File: python.info,  Node: Awaitables,  Next: Creating tasks,  Prev: Coroutines<3>,  Up: Coroutines and tasks

5.19.1.7 Awaitables
...................

We say that an object is an 'awaitable' object if it can be used in an
*note await: 1b9. expression.  Many asyncio APIs are designed to accept
awaitables.

There are three main types of 'awaitable' objects: 'coroutines',
'Tasks', and 'Futures'.

Coroutines
..........

Python coroutines are 'awaitables' and therefore can be awaited from
other coroutines:

     import asyncio

     async def nested():
         return 42

     async def main():
         # Nothing happens if we just call "nested()".
         # A coroutine object is created but not awaited,
         # so it *won't run at all*.
         nested()  # will raise a "RuntimeWarning".

         # Let's do it differently now and await it:
         print(await nested())  # will print "42".

     asyncio.run(main())

     Important: In this documentation the term “coroutine” can be used
     for two closely related concepts:

        * a 'coroutine function': an *note async def: 5d4. function;

        * a 'coroutine object': an object returned by calling a
          'coroutine function'.

Tasks
.....

'Tasks' are used to schedule coroutines 'concurrently'.

When a coroutine is wrapped into a 'Task' with functions like *note
asyncio.create_task(): 1bf. the coroutine is automatically scheduled to
run soon:

     import asyncio

     async def nested():
         return 42

     async def main():
         # Schedule nested() to run soon concurrently
         # with "main()".
         task = asyncio.create_task(nested())

         # "task" can now be used to cancel "nested()", or
         # can simply be awaited to wait until it is complete:
         await task

     asyncio.run(main())

Futures
.......

A *note Future: bec. is a special 'low-level' awaitable object that
represents an 'eventual result' of an asynchronous operation.

When a Future object is 'awaited' it means that the coroutine will wait
until the Future is resolved in some other place.

Future objects in asyncio are needed to allow callback-based code to be
used with async/await.

Normally 'there is no need' to create Future objects at the application
level code.

Future objects, sometimes exposed by libraries and some asyncio APIs,
can be awaited:

     async def main():
         await function_that_returns_a_future_object()

         # this is also valid:
         await asyncio.gather(
             function_that_returns_a_future_object(),
             some_python_coroutine()
         )

A good example of a low-level function that returns a Future object is
*note loop.run_in_executor(): 8f2.


File: python.info,  Node: Creating tasks,  Next: Task cancellation,  Prev: Awaitables,  Up: Coroutines and tasks

5.19.1.8 Creating tasks
.......................

'Source code:' Lib/asyncio/tasks.py(1)

__________________________________________________________________

 -- Function: asyncio.create_task (coro, *, name=None, context=None)

     Wrap the 'coro' *note coroutine: 348e. into a *note Task: 1be. and
     schedule its execution.  Return the Task object.

     If 'name' is not ‘None’, it is set as the name of the task using
     *note Task.set_name(): 9e8.

     An optional keyword-only 'context' argument allows specifying a
     custom *note contextvars.Context: 15dd. for the 'coro' to run in.
     The current context copy is created when no 'context' is provided.

     The task is executed in the loop returned by *note
     get_running_loop(): b24, *note RuntimeError: 195. is raised if
     there is no running loop in current thread.

          Note: *note asyncio.TaskGroup.create_task(): 1bc. is a new
          alternative leveraging structural concurrency; it allows for
          waiting for a group of related tasks with strong safety
          guarantees.

          Important: Save a reference to the result of this function, to
          avoid a task disappearing mid-execution.  The event loop only
          keeps weak references to tasks.  A task that isn’t referenced
          elsewhere may get garbage collected at any time, even before
          it’s done.  For reliable “fire-and-forget” background tasks,
          gather them in a collection:

               background_tasks = set()

               for i in range(10):
                   task = asyncio.create_task(some_coro(param=i))

                   # Add task to the set. This creates a strong reference.
                   background_tasks.add(task)

                   # To prevent keeping references to finished tasks forever,
                   # make each task remove its own reference from the set after
                   # completion:
                   task.add_done_callback(background_tasks.discard)

     Added in version 3.7.

     Changed in version 3.8: Added the 'name' parameter.

     Changed in version 3.11: Added the 'context' parameter.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/asyncio/tasks.py


File: python.info,  Node: Task cancellation,  Next: Task groups,  Prev: Creating tasks,  Up: Coroutines and tasks

5.19.1.9 Task cancellation
..........................

Tasks can easily and safely be cancelled.  When a task is cancelled,
*note asyncio.CancelledError: 1b8. will be raised in the task at the
next opportunity.

It is recommended that coroutines use ‘try/finally’ blocks to robustly
perform clean-up logic.  In case *note asyncio.CancelledError: 1b8. is
explicitly caught, it should generally be propagated when clean-up is
complete.  ‘asyncio.CancelledError’ directly subclasses *note
BaseException: 5be. so most code will not need to be aware of it.

The asyncio components that enable structured concurrency, like *note
asyncio.TaskGroup: 1b5. and *note asyncio.timeout(): 601, are
implemented using cancellation internally and might misbehave if a
coroutine swallows *note asyncio.CancelledError: 1b8.  Similarly, user
code should not generally call *note uncancel: 1bb.  However, in cases
when suppressing ‘asyncio.CancelledError’ is truly desired, it is
necessary to also call ‘uncancel()’ to completely remove the
cancellation state.


File: python.info,  Node: Task groups,  Next: Sleeping,  Prev: Task cancellation,  Up: Coroutines and tasks

5.19.1.10 Task groups
.....................

Task groups combine a task creation API with a convenient and reliable
way to wait for all tasks in the group to finish.

 -- Class: asyncio.TaskGroup

     An *note asynchronous context manager: 5ff. holding a group of
     tasks.  Tasks can be added to the group using *note create_task():
     1bf.  All tasks are awaited when the context manager exits.

     Added in version 3.11.

      -- Method: create_task (coro, *, name=None, context=None)

          Create a task in this task group.  The signature matches that
          of *note asyncio.create_task(): 1bf.  If the task group is
          inactive (e.g.  not yet entered, already finished, or in the
          process of shutting down), we will close the given ‘coro’.

          Changed in version 3.13: Close the given coroutine if the task
          group is not active.

Example:

     async def main():
         async with asyncio.TaskGroup() as tg:
             task1 = tg.create_task(some_coro(...))
             task2 = tg.create_task(another_coro(...))
         print(f"Both tasks have completed now: {task1.result()}, {task2.result()}")

The ‘async with’ statement will wait for all tasks in the group to
finish.  While waiting, new tasks may still be added to the group (for
example, by passing ‘tg’ into one of the coroutines and calling
‘tg.create_task()’ in that coroutine).  Once the last task has finished
and the ‘async with’ block is exited, no new tasks may be added to the
group.

The first time any of the tasks belonging to the group fails with an
exception other than *note asyncio.CancelledError: 1b8, the remaining
tasks in the group are cancelled.  No further tasks can then be added to
the group.  At this point, if the body of the ‘async with’ statement is
still active (i.e., *note __aexit__(): 1734. hasn’t been called yet),
the task directly containing the ‘async with’ statement is also
cancelled.  The resulting ‘asyncio.CancelledError’ will interrupt an
‘await’, but it will not bubble out of the containing ‘async with’
statement.

Once all tasks have finished, if any tasks have failed with an exception
other than *note asyncio.CancelledError: 1b8, those exceptions are
combined in an *note ExceptionGroup: 1b6. or *note BaseExceptionGroup:
25f. (as appropriate; see their documentation) which is then raised.

Two base exceptions are treated specially: If any task fails with *note
KeyboardInterrupt: 9dc. or *note SystemExit: d69, the task group still
cancels the remaining tasks and waits for them, but then the initial
‘KeyboardInterrupt’ or ‘SystemExit’ is re-raised instead of *note
ExceptionGroup: 1b6. or *note BaseExceptionGroup: 25f.

If the body of the ‘async with’ statement exits with an exception (so
*note __aexit__(): 1734. is called with an exception set), this is
treated the same as if one of the tasks failed: the remaining tasks are
cancelled and then waited for, and non-cancellation exceptions are
grouped into an exception group and raised.  The exception passed into
‘__aexit__()’, unless it is *note asyncio.CancelledError: 1b8, is also
included in the exception group.  The same special case is made for
*note KeyboardInterrupt: 9dc. and *note SystemExit: d69. as in the
previous paragraph.

Task groups are careful not to mix up the internal cancellation used to
“wake up” their *note __aexit__(): 1734. with cancellation requests for
the task in which they are running made by other parties.  In
particular, when one task group is syntactically nested in another, and
both experience an exception in one of their child tasks simultaneously,
the inner task group will process its exceptions, and then the outer
task group will receive another cancellation and process its own
exceptions.

In the case where a task group is cancelled externally and also must
raise an *note ExceptionGroup: 1b6, it will call the parent task’s *note
cancel(): 1b7. method.  This ensures that a *note
asyncio.CancelledError: 1b8. will be raised at the next *note await:
1b9, so the cancellation is not lost.

Task groups preserve the cancellation count reported by *note
asyncio.Task.cancelling(): 1ba.

Changed in version 3.13: Improved handling of simultaneous internal and
external cancellations and correct preservation of cancellation counts.

* Menu:

* Terminating a task group::


File: python.info,  Node: Terminating a task group,  Up: Task groups

5.19.1.11 Terminating a task group
..................................

While terminating a task group is not natively supported by the standard
library, termination can be achieved by adding an exception-raising task
to the task group and ignoring the raised exception:

     import asyncio
     from asyncio import TaskGroup

     class TerminateTaskGroup(Exception):
         """Exception raised to terminate a task group."""

     async def force_terminate_task_group():
         """Used to force termination of a task group."""
         raise TerminateTaskGroup()

     async def job(task_id, sleep_time):
         print(f'Task {task_id}: start')
         await asyncio.sleep(sleep_time)
         print(f'Task {task_id}: done')

     async def main():
         try:
             async with TaskGroup() as group:
                 # spawn some tasks
                 group.create_task(job(1, 0.5))
                 group.create_task(job(2, 1.5))
                 # sleep for 1 second
                 await asyncio.sleep(1)
                 # add an exception-raising task to force the group to terminate
                 group.create_task(force_terminate_task_group())
         except* TerminateTaskGroup:
             pass

     asyncio.run(main())

Expected output:

     Task 1: start
     Task 2: start
     Task 1: done


File: python.info,  Node: Sleeping,  Next: Running tasks concurrently,  Prev: Task groups,  Up: Coroutines and tasks

5.19.1.12 Sleeping
..................

 -- Function: async asyncio.sleep (delay, result=None)

     Block for 'delay' seconds.

     If 'result' is provided, it is returned to the caller when the
     coroutine completes.

     ‘sleep()’ always suspends the current task, allowing other tasks to
     run.

     Setting the delay to 0 provides an optimized path to allow other
     tasks to run.  This can be used by long-running functions to avoid
     blocking the event loop for the full duration of the function call.
     Example of coroutine displaying the current date every second for 5
     seconds:

          import asyncio
          import datetime as dt

          async def display_date():
              loop = asyncio.get_running_loop()
              end_time = loop.time() + 5.0
              while True:
                  print(dt.datetime.now())
                  if (loop.time() + 1.0) >= end_time:
                      break
                  await asyncio.sleep(1)

          asyncio.run(display_date())

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.13: Raises *note ValueError: 202. if 'delay'
     is *note nan: 666.


File: python.info,  Node: Running tasks concurrently,  Next: Eager task factory,  Prev: Sleeping,  Up: Coroutines and tasks

5.19.1.13 Running tasks concurrently
....................................

 -- Function: awaitable asyncio.gather (*aws, return_exceptions=False)

     Run *note awaitable objects: 34a5. in the 'aws' sequence
     'concurrently'.

     If any awaitable in 'aws' is a coroutine, it is automatically
     scheduled as a Task.

     If all awaitables are completed successfully, the result is an
     aggregate list of returned values.  The order of result values
     corresponds to the order of awaitables in 'aws'.

     If 'return_exceptions' is ‘False’ (default), the first raised
     exception is immediately propagated to the task that awaits on
     ‘gather()’.  Other awaitables in the 'aws' sequence 'won’t be
     cancelled' and will continue to run.

     If 'return_exceptions' is ‘True’, exceptions are treated the same
     as successful results, and aggregated in the result list.

     If ‘gather()’ is 'cancelled', all submitted awaitables (that have
     not completed yet) are also 'cancelled'.

     If any Task or Future from the 'aws' sequence is 'cancelled', it is
     treated as if it raised *note CancelledError: 1b8. – the ‘gather()’
     call is 'not' cancelled in this case.  This is to prevent the
     cancellation of one submitted Task/Future to cause other
     Tasks/Futures to be cancelled.

          Note: A new alternative to create and run tasks concurrently
          and wait for their completion is *note asyncio.TaskGroup: 1b5.
          'TaskGroup' provides stronger safety guarantees than 'gather'
          for scheduling a nesting of subtasks: if a task (or a subtask,
          a task scheduled by a task) raises an exception, 'TaskGroup'
          will, while 'gather' will not, cancel the remaining scheduled
          tasks.
     Example:

          import asyncio

          async def factorial(name, number):
              f = 1
              for i in range(2, number + 1):
                  print(f"Task {name}: Compute factorial({number}), currently i={i}...")
                  await asyncio.sleep(1)
                  f *= i
              print(f"Task {name}: factorial({number}) = {f}")
              return f

          async def main():
              # Schedule three calls *concurrently*:
              L = await asyncio.gather(
                  factorial("A", 2),
                  factorial("B", 3),
                  factorial("C", 4),
              )
              print(L)

          asyncio.run(main())

          # Expected output:
          #
          #     Task A: Compute factorial(2), currently i=2...
          #     Task B: Compute factorial(3), currently i=2...
          #     Task C: Compute factorial(4), currently i=2...
          #     Task A: factorial(2) = 2
          #     Task B: Compute factorial(3), currently i=3...
          #     Task C: Compute factorial(4), currently i=3...
          #     Task B: factorial(3) = 6
          #     Task C: Compute factorial(4), currently i=4...
          #     Task C: factorial(4) = 24
          #     [2, 6, 24]

          Note: If 'return_exceptions' is false, cancelling gather()
          after it has been marked done won’t cancel any submitted
          awaitables.  For instance, gather can be marked done after
          propagating an exception to the caller, therefore, calling
          ‘gather.cancel()’ after catching an exception (raised by one
          of the awaitables) from gather won’t cancel any other
          awaitables.

     Changed in version 3.7: If the 'gather' itself is cancelled, the
     cancellation is propagated regardless of 'return_exceptions'.

     Changed in version 3.10: Removed the 'loop' parameter.

     Deprecated since version 3.10: Deprecation warning is emitted if no
     positional arguments are provided or not all positional arguments
     are Future-like objects and there is no running event loop.


File: python.info,  Node: Eager task factory,  Next: Shielding from cancellation,  Prev: Running tasks concurrently,  Up: Coroutines and tasks

5.19.1.14 Eager task factory
............................

 -- Function: asyncio.eager_task_factory (loop, coro, *, name=None,
          context=None)

     A task factory for eager task execution.

     When using this factory (via *note
     loop.set_task_factory(asyncio.eager_task_factory): df4.),
     coroutines begin execution synchronously during *note Task: 1be.
     construction.  Tasks are only scheduled on the event loop if they
     block.  This can be a performance improvement as the overhead of
     loop scheduling is avoided for coroutines that complete
     synchronously.

     A common example where this is beneficial is coroutines which
     employ caching or memoization to avoid actual I/O when possible.

          Note: Immediate execution of the coroutine is a semantic
          change.  If the coroutine returns or raises, the task is never
          scheduled to the event loop.  If the coroutine execution
          blocks, the task is scheduled to the event loop.  This change
          may introduce behavior changes to existing applications.  For
          example, the application’s task execution order is likely to
          change.

     Added in version 3.12.

 -- Function: asyncio.create_eager_task_factory
          (custom_task_constructor)

     Create an eager task factory, similar to *note
     eager_task_factory(): 47a, using the provided
     'custom_task_constructor' when creating a new task instead of the
     default *note Task: 1be.

     'custom_task_constructor' must be a 'callable' with the signature
     matching the signature of *note Task.__init__: 1be.  The callable
     must return a *note asyncio.Task: 1be.-compatible object.

     This function returns a 'callable' intended to be used as a task
     factory of an event loop via *note loop.set_task_factory(factory):
     df4.).

     Added in version 3.12.


File: python.info,  Node: Shielding from cancellation,  Next: Timeouts,  Prev: Eager task factory,  Up: Coroutines and tasks

5.19.1.15 Shielding from cancellation
.....................................

 -- Function: awaitable asyncio.shield (aw)

     Protect an *note awaitable object: 34a5. from being *note
     cancelled: 1b7.

     If 'aw' is a coroutine it is automatically scheduled as a Task.

     The statement:

          task = asyncio.create_task(something())
          res = await shield(task)

     is equivalent to:

          res = await something()

     'except' that if the coroutine containing it is cancelled, the Task
     running in ‘something()’ is not cancelled.  From the point of view
     of ‘something()’, the cancellation did not happen.  Although its
     caller is still cancelled, so the “await” expression still raises a
     *note CancelledError: 1b8.

     If ‘something()’ is cancelled by other means (i.e.  from within
     itself) that would also cancel ‘shield()’.

     If it is desired to completely ignore cancellation (not
     recommended) the ‘shield()’ function should be combined with a
     try/except clause, as follows:

          task = asyncio.create_task(something())
          try:
              res = await shield(task)
          except CancelledError:
              res = None

          Important: Save a reference to tasks passed to this function,
          to avoid a task disappearing mid-execution.  The event loop
          only keeps weak references to tasks.  A task that isn’t
          referenced elsewhere may get garbage collected at any time,
          even before it’s done.

     Changed in version 3.10: Removed the 'loop' parameter.

     Deprecated since version 3.10: Deprecation warning is emitted if
     'aw' is not Future-like object and there is no running event loop.


File: python.info,  Node: Timeouts,  Next: Waiting primitives,  Prev: Shielding from cancellation,  Up: Coroutines and tasks

5.19.1.16 Timeouts
..................

 -- Function: asyncio.timeout (delay)

     Return an *note asynchronous context manager: 5ff. that can be used
     to limit the amount of time spent waiting on something.

     'delay' can either be ‘None’, or a float/int number of seconds to
     wait.  If 'delay' is ‘None’, no time limit will be applied; this
     can be useful if the delay is unknown when the context manager is
     created.

     In either case, the context manager can be rescheduled after
     creation using *note Timeout.reschedule(): 34b4.

     Example:

          async def main():
              async with asyncio.timeout(10):
                  await long_running_task()

     If ‘long_running_task’ takes more than 10 seconds to complete, the
     context manager will cancel the current task and handle the
     resulting *note asyncio.CancelledError: 1b8. internally,
     transforming it into a *note TimeoutError: 83b. which can be caught
     and handled.

          Note: The *note asyncio.timeout(): 601. context manager is
          what transforms the *note asyncio.CancelledError: 1b8. into a
          *note TimeoutError: 83b, which means the ‘TimeoutError’ can
          only be caught 'outside' of the context manager.

     Example of catching *note TimeoutError: 83b.:

          async def main():
              try:
                  async with asyncio.timeout(10):
                      await long_running_task()
              except TimeoutError:
                  print("The long operation timed out, but we've handled it.")

              print("This statement will run regardless.")

     The context manager produced by *note asyncio.timeout(): 601. can
     be rescheduled to a different deadline and inspected.

      -- Class: asyncio.Timeout (when)

          An *note asynchronous context manager: 5ff. for cancelling
          overdue coroutines.

          Prefer using *note asyncio.timeout(): 601. or *note
          asyncio.timeout_at(): 1958. rather than instantiating
          ‘Timeout’ directly.

          ‘when’ should be an absolute time at which the context should
          time out, as measured by the event loop’s clock:

             - If ‘when’ is ‘None’, the timeout will never trigger.

             - If ‘when < loop.time()’, the timeout will trigger on the
               next iteration of the event loop.

                -- Method: when () -> float | None

                    Return the current deadline, or ‘None’ if the
                    current deadline is not set.

                -- Method: reschedule (when: float | None)

                    Reschedule the timeout.

                -- Method: expired () -> bool

                    Return whether the context manager has exceeded its
                    deadline (expired).

     Example:

          async def main():
              try:
                  # We do not know the timeout when starting, so we pass ``None``.
                  async with asyncio.timeout(None) as cm:
                      # We know the timeout now, so we reschedule it.
                      new_deadline = get_running_loop().time() + 10
                      cm.reschedule(new_deadline)

                      await long_running_task()
              except TimeoutError:
                  pass

              if cm.expired():
                  print("Looks like we haven't finished on time.")

     Timeout context managers can be safely nested.

     Added in version 3.11.

 -- Function: asyncio.timeout_at (when)

     Similar to *note asyncio.timeout(): 601, except 'when' is the
     absolute time to stop waiting, or ‘None’.

     Example:

          async def main():
              loop = get_running_loop()
              deadline = loop.time() + 20
              try:
                  async with asyncio.timeout_at(deadline):
                      await long_running_task()
              except TimeoutError:
                  print("The long operation timed out, but we've handled it.")

              print("This statement will run regardless.")

     Added in version 3.11.

 -- Function: async asyncio.wait_for (aw, timeout)

     Wait for the 'aw' *note awaitable: 34a5. to complete with a
     timeout.

     If 'aw' is a coroutine it is automatically scheduled as a Task.

     'timeout' can either be ‘None’ or a float or int number of seconds
     to wait for.  If 'timeout' is ‘None’, block until the future
     completes.

     If a timeout occurs, it cancels the task and raises *note
     TimeoutError: 83b.

     To avoid the task *note cancellation: 1b7, wrap it in *note
     shield(): a7f.

     The function will wait until the future is actually cancelled, so
     the total wait time may exceed the 'timeout'.  If an exception
     happens during cancellation, it is propagated.

     If the wait is cancelled, the future 'aw' is also cancelled.
     Example:

          async def eternity():
              # Sleep for one hour
              await asyncio.sleep(3600)
              print('yay!')

          async def main():
              # Wait for at most 1 second
              try:
                  await asyncio.wait_for(eternity(), timeout=1.0)
              except TimeoutError:
                  print('timeout!')

          asyncio.run(main())

          # Expected output:
          #
          #     timeout!

     Changed in version 3.7: When 'aw' is cancelled due to a timeout,
     ‘wait_for’ waits for 'aw' to be cancelled.  Previously, it raised
     *note TimeoutError: 83b. immediately.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Raises *note TimeoutError: 83b. instead of
     *note asyncio.TimeoutError: 1858.


File: python.info,  Node: Waiting primitives,  Next: Running in threads,  Prev: Timeouts,  Up: Coroutines and tasks

5.19.1.17 Waiting primitives
............................

 -- Function: async asyncio.wait (aws, *, timeout=None,
          return_when=ALL_COMPLETED)

     Run *note Future: bec. and *note Task: 1be. instances in the 'aws'
     iterable concurrently and block until the condition specified by
     'return_when'.

     The 'aws' iterable must not be empty.

     Returns two sets of Tasks/Futures: ‘(done, pending)’.

     Usage:

          done, pending = await asyncio.wait(aws)

     'timeout' (a float or int), if specified, can be used to control
     the maximum number of seconds to wait before returning.

     Note that this function does not raise *note TimeoutError: 83b.
     Futures or Tasks that aren’t done when the timeout occurs are
     simply returned in the second set.

     'return_when' indicates when this function should return.  It must
     be one of the following constants:

     Constant                                               Description
                                                            
     --------------------------------------------------------------------------------------------------------------
                                                            
      -- Data: asyncio.FIRST_COMPLETED                      The function will return when any future finishes or
                                                            is cancelled.
                                                            
                                                            
      -- Data: asyncio.FIRST_EXCEPTION                      The function will return when any future finishes by
                                                            raising an exception.  If no future raises an
                                                            exception then it is equivalent to
                                                            *note ALL_COMPLETED: 34bb.
                                                            
                                                            
      -- Data: asyncio.ALL_COMPLETED                        The function will return when all futures finish or
                                                            are cancelled.
                                                            

     Unlike *note wait_for(): 602, ‘wait()’ does not cancel the futures
     when a timeout occurs.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Passing coroutine objects to ‘wait()’
     directly is forbidden.

     Changed in version 3.12: Added support for generators yielding
     tasks.

 -- Function: asyncio.as_completed (aws, *, timeout=None)

     Run *note awaitable objects: 34a5. in the 'aws' iterable
     concurrently.  The returned object can be iterated to obtain the
     results of the awaitables as they finish.

     The object returned by ‘as_completed()’ can be iterated as an *note
     asynchronous iterator: 1ab. or a plain *note iterator: 1ac.  When
     asynchronous iteration is used, the originally-supplied awaitables
     are yielded if they are tasks or futures.  This makes it easy to
     correlate previously-scheduled tasks with their results.  Example:

          ipv4_connect = create_task(open_connection("127.0.0.1", 80))
          ipv6_connect = create_task(open_connection("::1", 80))
          tasks = [ipv4_connect, ipv6_connect]

          async for earliest_connect in as_completed(tasks):
              # earliest_connect is done. The result can be obtained by
              # awaiting it or calling earliest_connect.result()
              reader, writer = await earliest_connect

              if earliest_connect is ipv6_connect:
                  print("IPv6 connection established.")
              else:
                  print("IPv4 connection established.")

     During asynchronous iteration, implicitly-created tasks will be
     yielded for supplied awaitables that aren’t tasks or futures.

     When used as a plain iterator, each iteration yields a new
     coroutine that returns the result or raises the exception of the
     next completed awaitable.  This pattern is compatible with Python
     versions older than 3.13:

          ipv4_connect = create_task(open_connection("127.0.0.1", 80))
          ipv6_connect = create_task(open_connection("::1", 80))
          tasks = [ipv4_connect, ipv6_connect]

          for next_connect in as_completed(tasks):
              # next_connect is not one of the original task objects. It must be
              # awaited to obtain the result value or raise the exception of the
              # awaitable that finishes next.
              reader, writer = await next_connect

     A *note TimeoutError: 83b. is raised if the timeout occurs before
     all awaitables are done.  This is raised by the ‘async for’ loop
     during asynchronous iteration or by the coroutines yielded during
     plain iteration.

     Changed in version 3.10: Removed the 'loop' parameter.

     Deprecated since version 3.10: Deprecation warning is emitted if
     not all awaitable objects in the 'aws' iterable are Future-like
     objects and there is no running event loop.

     Changed in version 3.12: Added support for generators yielding
     tasks.

     Changed in version 3.13: The result can now be used as either an
     *note asynchronous iterator: 1ab. or as a plain *note iterator:
     1ac. (previously it was only a plain iterator).


File: python.info,  Node: Running in threads,  Next: Scheduling from other threads,  Prev: Waiting primitives,  Up: Coroutines and tasks

5.19.1.18 Running in threads
............................

 -- Function: async asyncio.to_thread (func, /, *args, **kwargs)

     Asynchronously run function 'func' in a separate thread.

     Any *args and **kwargs supplied for this function are directly
     passed to 'func'.  Also, the current *note contextvars.Context:
     15dd. is propagated, allowing context variables from the event loop
     thread to be accessed in the separate thread.

     Return a coroutine that can be awaited to get the eventual result
     of 'func'.

     This coroutine function is primarily intended to be used for
     executing IO-bound functions/methods that would otherwise block the
     event loop if they were run in the main thread.  For example:

          def blocking_io():
              print(f"start blocking_io at {time.strftime('%X')}")
              # Note that time.sleep() can be replaced with any blocking
              # IO-bound operation, such as file operations.
              time.sleep(1)
              print(f"blocking_io complete at {time.strftime('%X')}")

          async def main():
              print(f"started main at {time.strftime('%X')}")

              await asyncio.gather(
                  asyncio.to_thread(blocking_io),
                  asyncio.sleep(1))

              print(f"finished main at {time.strftime('%X')}")


          asyncio.run(main())

          # Expected output:
          #
          # started main at 19:50:53
          # start blocking_io at 19:50:53
          # blocking_io complete at 19:50:54
          # finished main at 19:50:54

     Directly calling ‘blocking_io()’ in any coroutine would block the
     event loop for its duration, resulting in an additional 1 second of
     run time.  Instead, by using ‘asyncio.to_thread()’, we can run it
     in a separate thread without blocking the event loop.

          Note: Due to the *note GIL: 159, ‘asyncio.to_thread()’ can
          typically only be used to make IO-bound functions
          non-blocking.  However, for extension modules that release the
          GIL or alternative Python implementations that don’t have one,
          ‘asyncio.to_thread()’ can also be used for CPU-bound
          functions.

     Added in version 3.9.


File: python.info,  Node: Scheduling from other threads,  Next: Introspection,  Prev: Running in threads,  Up: Coroutines and tasks

5.19.1.19 Scheduling from other threads
.......................................

 -- Function: asyncio.run_coroutine_threadsafe (coro, loop)

     Submit a coroutine to the given event loop.  Thread-safe.

     Return a *note concurrent.futures.Future: 11f6. to wait for the
     result from another OS thread.

     This function is meant to be called from a different OS thread than
     the one where the event loop is running.  Example:

          # Create a coroutine
          coro = asyncio.sleep(1, result=3)

          # Submit the coroutine to a given loop
          future = asyncio.run_coroutine_threadsafe(coro, loop)

          # Wait for the result with an optional timeout argument
          assert future.result(timeout) == 3

     If an exception is raised in the coroutine, the returned Future
     will be notified.  It can also be used to cancel the task in the
     event loop:

          try:
              result = future.result(timeout)
          except TimeoutError:
              print('The coroutine took too long, cancelling the task...')
              future.cancel()
          except Exception as exc:
              print(f'The coroutine raised an exception: {exc!r}')
          else:
              print(f'The coroutine returned: {result!r}')

     See the *note concurrency and multithreading: 34be. section of the
     documentation.

     Unlike other asyncio functions this function requires the 'loop'
     argument to be passed explicitly.

     Added in version 3.5.1.


File: python.info,  Node: Introspection,  Next: Task object,  Prev: Scheduling from other threads,  Up: Coroutines and tasks

5.19.1.20 Introspection
.......................

 -- Function: asyncio.current_task (loop=None)

     Return the currently running *note Task: 1be. instance, or ‘None’
     if no task is running.

     If 'loop' is ‘None’ *note get_running_loop(): b24. is used to get
     the current loop.

     Added in version 3.7.

 -- Function: asyncio.all_tasks (loop=None)

     Return a set of not yet finished *note Task: 1be. objects run by
     the loop.

     If 'loop' is ‘None’, *note get_running_loop(): b24. is used for
     getting current loop.

     Added in version 3.7.

 -- Function: asyncio.iscoroutine (obj)

     Return ‘True’ if 'obj' is a coroutine object.

     Added in version 3.4.


File: python.info,  Node: Task object,  Prev: Introspection,  Up: Coroutines and tasks

5.19.1.21 Task object
.....................

 -- Class: asyncio.Task (coro, *, loop=None, name=None, context=None,
          eager_start=False)

     A *note Future-like: bec. object that runs a Python *note
     coroutine: 348e.  Not thread-safe.

     Tasks are used to run coroutines in event loops.  If a coroutine
     awaits on a Future, the Task suspends the execution of the
     coroutine and waits for the completion of the Future.  When the
     Future is 'done', the execution of the wrapped coroutine resumes.

     Event loops use cooperative scheduling: an event loop runs one Task
     at a time.  While a Task awaits for the completion of a Future, the
     event loop runs other Tasks, callbacks, or performs IO operations.

     Use the high-level *note asyncio.create_task(): 1bf. function to
     create Tasks, or the low-level *note loop.create_task(): 1c0. or
     *note ensure_future(): c98. functions.  Manual instantiation of
     Tasks is discouraged.

     To cancel a running Task use the *note cancel(): 1b7. method.
     Calling it will cause the Task to throw a *note CancelledError:
     1b8. exception into the wrapped coroutine.  If a coroutine is
     awaiting on a Future object during cancellation, the Future object
     will be cancelled.

     *note cancelled(): 34c2. can be used to check if the Task was
     cancelled.  The method returns ‘True’ if the wrapped coroutine did
     not suppress the *note CancelledError: 1b8. exception and was
     actually cancelled.

     *note asyncio.Task: 1be. inherits from *note Future: bec. all of
     its APIs except *note Future.set_result(): 34c3. and *note
     Future.set_exception(): c9f.

     An optional keyword-only 'context' argument allows specifying a
     custom *note contextvars.Context: 15dd. for the 'coro' to run in.
     If no 'context' is provided, the Task copies the current context
     and later runs its coroutine in the copied context.

     An optional keyword-only 'eager_start' argument allows eagerly
     starting the execution of the *note asyncio.Task: 1be. at task
     creation time.  If set to ‘True’ and the event loop is running, the
     task will start executing the coroutine immediately, until the
     first time the coroutine blocks.  If the coroutine returns or
     raises without blocking, the task will be finished eagerly and will
     skip scheduling to the event loop.

     Changed in version 3.7: Added support for the *note contextvars:
     24. module.

     Changed in version 3.8: Added the 'name' parameter.

     Deprecated since version 3.10: Deprecation warning is emitted if
     'loop' is not specified and there is no running event loop.

     Changed in version 3.11: Added the 'context' parameter.

     Changed in version 3.12: Added the 'eager_start' parameter.

      -- Method: done ()

          Return ‘True’ if the Task is 'done'.

          A Task is 'done' when the wrapped coroutine either returned a
          value, raised an exception, or the Task was cancelled.

      -- Method: result ()

          Return the result of the Task.

          If the Task is 'done', the result of the wrapped coroutine is
          returned (or if the coroutine raised an exception, that
          exception is re-raised.)

          If the Task has been 'cancelled', this method raises a *note
          CancelledError: 1b8. exception.

          If the Task’s result isn’t yet available, this method raises
          an *note InvalidStateError: 34c6. exception.

      -- Method: exception ()

          Return the exception of the Task.

          If the wrapped coroutine raised an exception that exception is
          returned.  If the wrapped coroutine returned normally this
          method returns ‘None’.

          If the Task has been 'cancelled', this method raises a *note
          CancelledError: 1b8. exception.

          If the Task isn’t 'done' yet, this method raises an *note
          InvalidStateError: 34c6. exception.

      -- Method: add_done_callback (callback, *, context=None)

          Add a callback to be run when the Task is 'done'.

          This method should only be used in low-level callback-based
          code.

          See the documentation of *note Future.add_done_callback():
          b21. for more details.

      -- Method: remove_done_callback (callback)

          Remove 'callback' from the callbacks list.

          This method should only be used in low-level callback-based
          code.

          See the documentation of *note Future.remove_done_callback():
          16a9. for more details.

      -- Method: get_stack (*, limit=None)

          Return the list of stack frames for this Task.

          If the wrapped coroutine is not done, this returns the stack
          where it is suspended.  If the coroutine has completed
          successfully or was cancelled, this returns an empty list.  If
          the coroutine was terminated by an exception, this returns the
          list of traceback frames.

          The frames are always ordered from oldest to newest.

          Only one stack frame is returned for a suspended coroutine.

          The optional 'limit' argument sets the maximum number of
          frames to return; by default all available frames are
          returned.  The ordering of the returned list differs depending
          on whether a stack or a traceback is returned: the newest
          frames of a stack are returned, but the oldest frames of a
          traceback are returned.  (This matches the behavior of the
          traceback module.)

      -- Method: print_stack (*, limit=None, file=None)

          Print the stack or traceback for this Task.

          This produces output similar to that of the traceback module
          for the frames retrieved by *note get_stack(): 34ca.

          The 'limit' argument is passed to *note get_stack(): 34ca.
          directly.

          The 'file' argument is an I/O stream to which the output is
          written; by default output is written to *note sys.stdout:
          aec.

      -- Method: get_coro ()

          Return the coroutine object wrapped by the ‘Task’.

               Note: This will return ‘None’ for Tasks which have
               already completed eagerly.  See the *note Eager Task
               Factory: 34b0.

          Added in version 3.8.

          Changed in version 3.12: Newly added eager task execution
          means result may be ‘None’.

      -- Method: get_context ()

          Return the *note contextvars.Context: 15dd. object associated
          with the task.

          Added in version 3.12.

      -- Method: get_name ()

          Return the name of the Task.

          If no name has been explicitly assigned to the Task, the
          default asyncio Task implementation generates a default name
          during instantiation.

          Added in version 3.8.

      -- Method: set_name (value)

          Set the name of the Task.

          The 'value' argument can be any object, which is then
          converted to a string.

          In the default Task implementation, the name will be visible
          in the *note repr(): 803. output of a task object.

          Added in version 3.8.

      -- Method: cancel (msg=None)

          Request the Task to be cancelled.

          If the Task is already 'done' or 'cancelled', return ‘False’,
          otherwise, return ‘True’.

          The method arranges for a *note CancelledError: 1b8. exception
          to be thrown into the wrapped coroutine on the next cycle of
          the event loop.

          The coroutine then has a chance to clean up or even deny the
          request by suppressing the exception with a *note try: 6ec. …
          … ‘except CancelledError’ … *note finally: 9d5. block.
          Therefore, unlike *note Future.cancel(): 194f, ‘Task.cancel()’
          does not guarantee that the Task will be cancelled, although
          suppressing cancellation completely is not common and is
          actively discouraged.  Should the coroutine nevertheless
          decide to suppress the cancellation, it needs to call *note
          Task.uncancel(): 1bb. in addition to catching the exception.

          Changed in version 3.9: Added the 'msg' parameter.

          Changed in version 3.11: The ‘msg’ parameter is propagated
          from cancelled task to its awaiter.

          The following example illustrates how coroutines can intercept
          the cancellation request:

               async def cancel_me():
                   print('cancel_me(): before sleep')

                   try:
                       # Wait for 1 hour
                       await asyncio.sleep(3600)
                   except asyncio.CancelledError:
                       print('cancel_me(): cancel sleep')
                       raise
                   finally:
                       print('cancel_me(): after sleep')

               async def main():
                   # Create a "cancel_me" Task
                   task = asyncio.create_task(cancel_me())

                   # Wait for 1 second
                   await asyncio.sleep(1)

                   task.cancel()
                   try:
                       await task
                   except asyncio.CancelledError:
                       print("main(): cancel_me is cancelled now")

               asyncio.run(main())

               # Expected output:
               #
               #     cancel_me(): before sleep
               #     cancel_me(): cancel sleep
               #     cancel_me(): after sleep
               #     main(): cancel_me is cancelled now

      -- Method: cancelled ()

          Return ‘True’ if the Task is 'cancelled'.

          The Task is 'cancelled' when the cancellation was requested
          with *note cancel(): 1b7. and the wrapped coroutine propagated
          the *note CancelledError: 1b8. exception thrown into it.

      -- Method: uncancel ()

          Decrement the count of cancellation requests to this Task.

          Returns the remaining number of cancellation requests.

          Note that once execution of a cancelled task completed,
          further calls to ‘uncancel()’ are ineffective.

          Added in version 3.11.

          This method is used by asyncio’s internals and isn’t expected
          to be used by end-user code.  In particular, if a Task gets
          successfully uncancelled, this allows for elements of
          structured concurrency like *note Task groups: 34aa. and *note
          asyncio.timeout(): 601. to continue running, isolating
          cancellation to the respective structured block.  For example:

               async def make_request_with_timeout():
                   try:
                       async with asyncio.timeout(1):
                           # Structured block affected by the timeout:
                           await make_request()
                           await make_another_request()
                   except TimeoutError:
                       log("There was a timeout")
                   # Outer code not affected by the timeout:
                   await unrelated_code()

          While the block with ‘make_request()’ and
          ‘make_another_request()’ might get cancelled due to the
          timeout, ‘unrelated_code()’ should continue running even in
          case of the timeout.  This is implemented with ‘uncancel()’.
          *note TaskGroup: 1b5. context managers use *note uncancel():
          1bb. in a similar fashion.

          If end-user code is, for some reason, suppressing cancellation
          by catching *note CancelledError: 1b8, it needs to call this
          method to remove the cancellation state.

          When this method decrements the cancellation count to zero,
          the method checks if a previous *note cancel(): 1b7. call had
          arranged for *note CancelledError: 1b8. to be thrown into the
          task.  If it hasn’t been thrown yet, that arrangement will be
          rescinded (by resetting the internal ‘_must_cancel’ flag).

     Changed in version 3.13: Changed to rescind pending cancellation
     requests upon reaching zero.

      -- Method: cancelling ()

          Return the number of pending cancellation requests to this
          Task, i.e., the number of calls to *note cancel(): 1b7. less
          the number of *note uncancel(): 1bb. calls.

          Note that if this number is greater than zero but the Task is
          still executing, *note cancelled(): 34c2. will still return
          ‘False’.  This is because this number can be lowered by
          calling *note uncancel(): 1bb, which can lead to the task not
          being cancelled after all if the cancellation requests go down
          to zero.

          This method is used by asyncio’s internals and isn’t expected
          to be used by end-user code.  See *note uncancel(): 1bb. for
          more details.

          Added in version 3.11.


File: python.info,  Node: Streams,  Next: Synchronization Primitives,  Prev: Coroutines and tasks,  Up: asyncio — Asynchronous I/O

5.19.1.22 Streams
.................

'Source code:' Lib/asyncio/streams.py(1)

__________________________________________________________________

Streams are high-level async/await-ready primitives to work with network
connections.  Streams allow sending and receiving data without using
callbacks or low-level protocols and transports.  Here is an example of
a TCP echo client written using asyncio streams:

     import asyncio

     async def tcp_echo_client(message):
         reader, writer = await asyncio.open_connection(
             '127.0.0.1', 8888)

         print(f'Send: {message!r}')
         writer.write(message.encode())
         await writer.drain()

         data = await reader.read(100)
         print(f'Received: {data.decode()!r}')

         print('Close the connection')
         writer.close()
         await writer.wait_closed()

     asyncio.run(tcp_echo_client('Hello World!'))

See also the *note Examples: 34d1. section below.

Stream Functions
................

The following top-level asyncio functions can be used to create and work
with streams:

 -- Function: async asyncio.open_connection (host=None, port=None, *,
          limit=None, ssl=None, family=0, proto=0, flags=0, sock=None,
          local_addr=None, server_hostname=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          happy_eyeballs_delay=None, interleave=None)

     Establish a network connection and return a pair of ‘(reader,
     writer)’ objects.

     The returned 'reader' and 'writer' objects are instances of *note
     StreamReader: 15b6. and *note StreamWriter: 180f. classes.

     'limit' determines the buffer size limit used by the returned *note
     StreamReader: 15b6. instance.  By default the 'limit' is set to 64
     KiB.

     The rest of the arguments are passed directly to *note
     loop.create_connection(): 606.

          Note: The 'sock' argument transfers ownership of the socket to
          the *note StreamWriter: 180f. created.  To close the socket,
          call its *note close(): 34d2. method.

     Changed in version 3.7: Added the 'ssl_handshake_timeout'
     parameter.

     Changed in version 3.8: Added the 'happy_eyeballs_delay' and
     'interleave' parameters.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

 -- Function: async asyncio.start_server (client_connected_cb,
          host=None, port=None, *, limit=None, family=socket.AF_UNSPEC,
          flags=socket.AI_PASSIVE, sock=None, backlog=100, ssl=None,
          reuse_address=None, reuse_port=None, keep_alive=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          start_serving=True)

     Start a socket server.

     The 'client_connected_cb' callback is called whenever a new client
     connection is established.  It receives a ‘(reader, writer)’ pair
     as two arguments, instances of the *note StreamReader: 15b6. and
     *note StreamWriter: 180f. classes.

     'client_connected_cb' can be a plain callable or a *note coroutine
     function: 348e.; if it is a coroutine function, it will be
     automatically scheduled as a *note Task: 1be.

     'limit' determines the buffer size limit used by the returned *note
     StreamReader: 15b6. instance.  By default the 'limit' is set to 64
     KiB.

     The rest of the arguments are passed directly to *note
     loop.create_server(): b2c.

          Note: The 'sock' argument transfers ownership of the socket to
          the server created.  To close the socket, call the server’s
          *note close(): 34d3. method.

     Changed in version 3.7: Added the 'ssl_handshake_timeout' and
     'start_serving' parameters.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

     Changed in version 3.13: Added the 'keep_alive' parameter.

Unix Sockets
............

 -- Function: async asyncio.open_unix_connection (path=None, *,
          limit=None, ssl=None, sock=None, server_hostname=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

     Establish a Unix socket connection and return a pair of ‘(reader,
     writer)’.

     Similar to *note open_connection(): b31. but operates on Unix
     sockets.

     See also the documentation of *note loop.create_unix_connection():
     34d5.

          Note: The 'sock' argument transfers ownership of the socket to
          the *note StreamWriter: 180f. created.  To close the socket,
          call its *note close(): 34d2. method.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.7: Added the 'ssl_handshake_timeout'
     parameter.  The 'path' parameter can now be a *note path-like
     object: 2a0.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

 -- Function: async asyncio.start_unix_server (client_connected_cb,
          path=None, *, limit=None, sock=None, backlog=100, ssl=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          start_serving=True, cleanup_socket=True)

     Start a Unix socket server.

     Similar to *note start_server(): b32. but works with Unix sockets.

     If 'cleanup_socket' is true then the Unix socket will automatically
     be removed from the filesystem when the server is closed, unless
     the socket has been replaced after the server has been created.

     See also the documentation of *note loop.create_unix_server(): 1ae.

          Note: The 'sock' argument transfers ownership of the socket to
          the server created.  To close the socket, call the server’s
          *note close(): 34d3. method.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.7: Added the 'ssl_handshake_timeout' and
     'start_serving' parameters.  The 'path' parameter can now be a
     *note path-like object: 2a0.

     Changed in version 3.10: Removed the 'loop' parameter.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

     Changed in version 3.13: Added the 'cleanup_socket' parameter.

* Menu:

* StreamReader::
* StreamWriter::
* Examples: Examples<15>.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/streams.py


File: python.info,  Node: StreamReader,  Next: StreamWriter,  Up: Streams

5.19.1.23 StreamReader
......................

 -- Class: asyncio.StreamReader

     Represents a reader object that provides APIs to read data from the
     IO stream.  As an *note asynchronous iterable: da2, the object
     supports the *note async for: ac0. statement.

     It is not recommended to instantiate 'StreamReader' objects
     directly; use *note open_connection(): b31. and *note
     start_server(): b32. instead.

      -- Method: feed_eof ()

          Acknowledge the EOF.

      -- Method: async read (n=-1)

          Read up to 'n' bytes from the stream.

          If 'n' is not provided or set to ‘-1’, read until EOF, then
          return all read *note bytes: 1c2.  If EOF was received and the
          internal buffer is empty, return an empty ‘bytes’ object.

          If 'n' is ‘0’, return an empty ‘bytes’ object immediately.

          If 'n' is positive, return at most 'n' available ‘bytes’ as
          soon as at least 1 byte is available in the internal buffer.
          If EOF is received before any byte is read, return an empty
          ‘bytes’ object.

      -- Method: async readline ()

          Read one line, where “line” is a sequence of bytes ending with
          ‘\n’.

          If EOF is received and ‘\n’ was not found, the method returns
          partially read data.

          If EOF is received and the internal buffer is empty, return an
          empty ‘bytes’ object.

      -- Method: async readexactly (n)

          Read exactly 'n' bytes.

          Raise an *note IncompleteReadError: 1a8f. if EOF is reached
          before 'n' can be read.  Use the *note
          IncompleteReadError.partial: 34db. attribute to get the
          partially read data.

      -- Method: async readuntil (separator=b'\n')

          Read data from the stream until 'separator' is found.

          On success, the data and separator will be removed from the
          internal buffer (consumed).  Returned data will include the
          separator at the end.

          If the amount of data read exceeds the configured stream
          limit, a *note LimitOverrunError: 34dc. exception is raised,
          and the data is left in the internal buffer and can be read
          again.

          If EOF is reached before the complete separator is found, an
          *note IncompleteReadError: 1a8f. exception is raised, and the
          internal buffer is reset.  The *note
          IncompleteReadError.partial: 34db. attribute may contain a
          portion of the separator.

          The 'separator' may also be a tuple of separators.  In this
          case the return value will be the shortest possible that has
          any separator as the suffix.  For the purposes of *note
          LimitOverrunError: 34dc, the shortest possible separator is
          considered to be the one that matched.

          Added in version 3.5.2.

          Changed in version 3.13: The 'separator' parameter may now be
          a *note tuple: 373. of separators.

      -- Method: at_eof ()

          Return ‘True’ if the buffer is empty and *note feed_eof():
          34d8. was called.


File: python.info,  Node: StreamWriter,  Next: Examples<15>,  Prev: StreamReader,  Up: Streams

5.19.1.24 StreamWriter
......................

 -- Class: asyncio.StreamWriter

     Represents a writer object that provides APIs to write data to the
     IO stream.

     It is not recommended to instantiate 'StreamWriter' objects
     directly; use *note open_connection(): b31. and *note
     start_server(): b32. instead.

      -- Method: write (data)

          The method attempts to write the 'data' to the underlying
          socket immediately.  If that fails, the data is queued in an
          internal write buffer until it can be sent.

          The 'data' buffer should be a bytes, bytearray, or
          C-contiguous one-dimensional memoryview object.

          The method should be used along with the ‘drain()’ method:

               stream.write(data)
               await stream.drain()

      -- Method: writelines (data)

          The method writes a list (or any iterable) of bytes to the
          underlying socket immediately.  If that fails, the data is
          queued in an internal write buffer until it can be sent.

          The method should be used along with the ‘drain()’ method:

               stream.writelines(lines)
               await stream.drain()

      -- Method: close ()

          The method closes the stream and the underlying socket.

          The method should be used, though not mandatory, along with
          the ‘wait_closed()’ method:

               stream.close()
               await stream.wait_closed()

      -- Method: can_write_eof ()

          Return ‘True’ if the underlying transport supports the *note
          write_eof(): 34e2. method, ‘False’ otherwise.

      -- Method: write_eof ()

          Close the write end of the stream after the buffered write
          data is flushed.

      -- Attribute: transport

          Return the underlying asyncio transport.

      -- Method: get_extra_info (name, default=None)

          Access optional transport information; see *note
          BaseTransport.get_extra_info(): ab1. for details.

      -- Method: async drain ()

          Wait until it is appropriate to resume writing to the stream.
          Example:

               writer.write(data)
               await writer.drain()

          This is a flow control method that interacts with the
          underlying IO write buffer.  When the size of the buffer
          reaches the high watermark, 'drain()' blocks until the size of
          the buffer is drained down to the low watermark and writing
          can be resumed.  When there is nothing to wait for, the
          ‘drain()’ returns immediately.

      -- Method: async start_tls (sslcontext, *, server_hostname=None,
               ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

          Upgrade an existing stream-based connection to TLS.

          Parameters:

             * 'sslcontext': a configured instance of *note SSLContext:
               294.

             * 'server_hostname': sets or overrides the host name that
               the target server’s certificate will be matched against.

             * 'ssl_handshake_timeout' is the time in seconds to wait
               for the TLS handshake to complete before aborting the
               connection.  ‘60.0’ seconds if ‘None’ (default).

             * 'ssl_shutdown_timeout' is the time in seconds to wait for
               the SSL shutdown to complete before aborting the
               connection.  ‘30.0’ seconds if ‘None’ (default).

          Added in version 3.11.

          Changed in version 3.12: Added the 'ssl_shutdown_timeout'
          parameter.

      -- Method: is_closing ()

          Return ‘True’ if the stream is closed or in the process of
          being closed.

          Added in version 3.7.

      -- Method: async wait_closed ()

          Wait until the stream is closed.

          Should be called after *note close(): 34d2. to wait until the
          underlying connection is closed, ensuring that all data has
          been flushed before e.g.  exiting the program.

          Added in version 3.7.


File: python.info,  Node: Examples<15>,  Prev: StreamWriter,  Up: Streams

5.19.1.25 Examples
..................

* Menu:

* TCP echo client using streams::
* TCP echo server using streams::
* Get HTTP headers::
* Register an open socket to wait for data using streams::


File: python.info,  Node: TCP echo client using streams,  Next: TCP echo server using streams,  Up: Examples<15>

5.19.1.26 TCP echo client using streams
.......................................

TCP echo client using the *note asyncio.open_connection(): b31.
function:

     import asyncio

     async def tcp_echo_client(message):
         reader, writer = await asyncio.open_connection(
             '127.0.0.1', 8888)

         print(f'Send: {message!r}')
         writer.write(message.encode())
         await writer.drain()

         data = await reader.read(100)
         print(f'Received: {data.decode()!r}')

         print('Close the connection')
         writer.close()
         await writer.wait_closed()

     asyncio.run(tcp_echo_client('Hello World!'))

See also
........

The *note TCP echo client protocol: 34e7. example uses the low-level
*note loop.create_connection(): 606. method.


File: python.info,  Node: TCP echo server using streams,  Next: Get HTTP headers,  Prev: TCP echo client using streams,  Up: Examples<15>

5.19.1.27 TCP echo server using streams
.......................................

TCP echo server using the *note asyncio.start_server(): b32. function:

     import asyncio

     async def handle_echo(reader, writer):
         data = await reader.read(100)
         message = data.decode()
         addr = writer.get_extra_info('peername')

         print(f"Received {message!r} from {addr!r}")

         print(f"Send: {message!r}")
         writer.write(data)
         await writer.drain()

         print("Close the connection")
         writer.close()
         await writer.wait_closed()

     async def main():
         server = await asyncio.start_server(
             handle_echo, '127.0.0.1', 8888)

         addrs = ', '.join(str(sock.getsockname()) for sock in server.sockets)
         print(f'Serving on {addrs}')

         async with server:
             await server.serve_forever()

     asyncio.run(main())

See also
........

The *note TCP echo server protocol: 34ea. example uses the *note
loop.create_server(): b2c. method.


File: python.info,  Node: Get HTTP headers,  Next: Register an open socket to wait for data using streams,  Prev: TCP echo server using streams,  Up: Examples<15>

5.19.1.28 Get HTTP headers
..........................

Simple example querying HTTP headers of the URL passed on the command
line:

     import asyncio
     import urllib.parse
     import sys

     async def print_http_headers(url):
         url = urllib.parse.urlsplit(url)
         if url.scheme == 'https':
             reader, writer = await asyncio.open_connection(
                 url.hostname, 443, ssl=True)
         else:
             reader, writer = await asyncio.open_connection(
                 url.hostname, 80)

         query = (
             f"HEAD {url.path or '/'} HTTP/1.0\r\n"
             f"Host: {url.hostname}\r\n"
             f"\r\n"
         )

         writer.write(query.encode('latin-1'))
         while True:
             line = await reader.readline()
             if not line:
                 break

             line = line.decode('latin1').rstrip()
             if line:
                 print(f'HTTP header> {line}')

         # Ignore the body, close the socket
         writer.close()
         await writer.wait_closed()

     url = sys.argv[1]
     asyncio.run(print_http_headers(url))

Usage:

     python example.py http://example.com/path/page.html

or with HTTPS:

     python example.py https://example.com/path/page.html


File: python.info,  Node: Register an open socket to wait for data using streams,  Prev: Get HTTP headers,  Up: Examples<15>

5.19.1.29 Register an open socket to wait for data using streams
................................................................

Coroutine waiting until a socket receives data using the *note
open_connection(): b31. function:

     import asyncio
     import socket

     async def wait_for_data():
         # Get a reference to the current event loop because
         # we want to access low-level APIs.
         loop = asyncio.get_running_loop()

         # Create a pair of connected sockets.
         rsock, wsock = socket.socketpair()

         # Register the open socket to wait for data.
         reader, writer = await asyncio.open_connection(sock=rsock)

         # Simulate the reception of data from the network
         loop.call_soon(wsock.send, 'abc'.encode())

         # Wait for data
         data = await reader.read(100)

         # Got data, we are done: close the socket
         print("Received:", data.decode())
         writer.close()
         await writer.wait_closed()

         # Close the second socket
         wsock.close()

     asyncio.run(wait_for_data())

See also
........

The *note register an open socket to wait for data using a protocol:
34ee. example uses a low-level protocol and the *note
loop.create_connection(): 606. method.

The *note watch a file descriptor for read events: 34ef. example uses
the low-level *note loop.add_reader(): 34f0. method to watch a file
descriptor.


File: python.info,  Node: Synchronization Primitives,  Next: Subprocesses,  Prev: Streams,  Up: asyncio — Asynchronous I/O

5.19.1.30 Synchronization Primitives
....................................

'Source code:' Lib/asyncio/locks.py(1)

__________________________________________________________________

asyncio synchronization primitives are designed to be similar to those
of the *note threading: ed. module with two important caveats:

   * asyncio primitives are not thread-safe, therefore they should not
     be used for OS thread synchronization (use *note threading: ed. for
     that);

   * methods of these synchronization primitives do not accept the
     'timeout' argument; use the *note asyncio.wait_for(): 602. function
     to perform operations with timeouts.

asyncio has the following basic synchronization primitives:

   * *note Lock: a80.

   * *note Event: a81.

   * *note Condition: a82.

   * *note Semaphore: a83.

   * *note BoundedSemaphore: a84.

   * *note Barrier: 604.

__________________________________________________________________

* Menu:

* Lock::
* Event::
* Condition::
* Semaphore::
* BoundedSemaphore::
* Barrier::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/asyncio/locks.py


File: python.info,  Node: Lock,  Next: Event,  Up: Synchronization Primitives

5.19.1.31 Lock
..............

 -- Class: asyncio.Lock

     Implements a mutex lock for asyncio tasks.  Not thread-safe.

     An asyncio lock can be used to guarantee exclusive access to a
     shared resource.

     The preferred way to use a Lock is an *note async with: 5d8.
     statement:

          lock = asyncio.Lock()

          # ... later
          async with lock:
              # access shared state

     which is equivalent to:

          lock = asyncio.Lock()

          # ... later
          await lock.acquire()
          try:
              # access shared state
          finally:
              lock.release()

     Changed in version 3.10: Removed the 'loop' parameter.

      -- Method: async acquire ()

          Acquire the lock.

          This method waits until the lock is 'unlocked', sets it to
          'locked' and returns ‘True’.

          When more than one coroutine is blocked in ‘acquire()’ waiting
          for the lock to be unlocked, only one coroutine eventually
          proceeds.

          Acquiring a lock is 'fair': the coroutine that proceeds will
          be the first coroutine that started waiting on the lock.

      -- Method: release ()

          Release the lock.

          When the lock is 'locked', reset it to 'unlocked' and return.

          If the lock is 'unlocked', a *note RuntimeError: 195. is
          raised.

      -- Method: locked ()

          Return ‘True’ if the lock is 'locked'.


File: python.info,  Node: Event,  Next: Condition,  Prev: Lock,  Up: Synchronization Primitives

5.19.1.32 Event
...............

 -- Class: asyncio.Event

     An event object.  Not thread-safe.

     An asyncio event can be used to notify multiple asyncio tasks that
     some event has happened.

     An Event object manages an internal flag that can be set to 'true'
     with the *note set(): 34f9. method and reset to 'false' with the
     *note clear(): 34fa. method.  The *note wait(): 34fb. method blocks
     until the flag is set to 'true'.  The flag is set to 'false'
     initially.

     Changed in version 3.10: Removed the 'loop' parameter.

     Example:

          async def waiter(event):
              print('waiting for it ...')
              await event.wait()
              print('... got it!')

          async def main():
              # Create an Event object.
              event = asyncio.Event()

              # Spawn a Task to wait until 'event' is set.
              waiter_task = asyncio.create_task(waiter(event))

              # Sleep for 1 second and set the event.
              await asyncio.sleep(1)
              event.set()

              # Wait until the waiter task is finished.
              await waiter_task

          asyncio.run(main())

      -- Method: async wait ()

          Wait until the event is set.

          If the event is set, return ‘True’ immediately.  Otherwise
          block until another task calls *note set(): 34f9.

      -- Method: set ()

          Set the event.

          All tasks waiting for event to be set will be immediately
          awakened.

      -- Method: clear ()

          Clear (unset) the event.

          Subsequent tasks awaiting on *note wait(): 34fb. will now
          block until the *note set(): 34f9. method is called again.

      -- Method: is_set ()

          Return ‘True’ if the event is set.


File: python.info,  Node: Condition,  Next: Semaphore,  Prev: Event,  Up: Synchronization Primitives

5.19.1.33 Condition
...................

 -- Class: asyncio.Condition (lock=None)

     A Condition object.  Not thread-safe.

     An asyncio condition primitive can be used by a task to wait for
     some event to happen and then get exclusive access to a shared
     resource.

     In essence, a Condition object combines the functionality of an
     *note Event: a81. and a *note Lock: a80.  It is possible to have
     multiple Condition objects share one Lock, which allows
     coordinating exclusive access to a shared resource between
     different tasks interested in particular states of that shared
     resource.

     The optional 'lock' argument must be a *note Lock: a80. object or
     ‘None’.  In the latter case a new Lock object is created
     automatically.

     Changed in version 3.10: Removed the 'loop' parameter.

     The preferred way to use a Condition is an *note async with: 5d8.
     statement:

          cond = asyncio.Condition()

          # ... later
          async with cond:
              await cond.wait()

     which is equivalent to:

          cond = asyncio.Condition()

          # ... later
          await cond.acquire()
          try:
              await cond.wait()
          finally:
              cond.release()

      -- Method: async acquire ()

          Acquire the underlying lock.

          This method waits until the underlying lock is 'unlocked',
          sets it to 'locked' and returns ‘True’.

      -- Method: notify (n=1)

          Wake up 'n' tasks (1 by default) waiting on this condition.
          If fewer than 'n' tasks are waiting they are all awakened.

          The lock must be acquired before this method is called and
          released shortly after.  If called with an 'unlocked' lock a
          *note RuntimeError: 195. error is raised.

      -- Method: locked ()

          Return ‘True’ if the underlying lock is acquired.

      -- Method: notify_all ()

          Wake up all tasks waiting on this condition.

          This method acts like *note notify(): 178d, but wakes up all
          waiting tasks.

          The lock must be acquired before this method is called and
          released shortly after.  If called with an 'unlocked' lock a
          *note RuntimeError: 195. error is raised.

      -- Method: release ()

          Release the underlying lock.

          When invoked on an unlocked lock, a *note RuntimeError: 195.
          is raised.

      -- Method: async wait ()

          Wait until notified.

          If the calling task has not acquired the lock when this method
          is called, a *note RuntimeError: 195. is raised.

          This method releases the underlying lock, and then blocks
          until it is awakened by a *note notify(): 178d. or *note
          notify_all(): 3501. call.  Once awakened, the Condition
          re-acquires its lock and this method returns ‘True’.

          Note that a task 'may' return from this call spuriously, which
          is why the caller should always re-check the state and be
          prepared to ‘wait()’ again.  For this reason, you may prefer
          to use *note wait_for(): 3503. instead.

      -- Method: async wait_for (predicate)

          Wait until a predicate becomes 'true'.

          The predicate must be a callable which result will be
          interpreted as a boolean value.  The method will repeatedly
          *note wait(): 17b8. until the predicate evaluates to 'true'.
          The final value is the return value.


File: python.info,  Node: Semaphore,  Next: BoundedSemaphore,  Prev: Condition,  Up: Synchronization Primitives

5.19.1.34 Semaphore
...................

 -- Class: asyncio.Semaphore (value=1)

     A Semaphore object.  Not thread-safe.

     A semaphore manages an internal counter which is decremented by
     each *note acquire(): 17b9. call and incremented by each *note
     release(): 3505. call.  The counter can never go below zero; when
     ‘acquire()’ finds that it is zero, it blocks, waiting until some
     task calls ‘release()’.

     The optional 'value' argument gives the initial value for the
     internal counter (‘1’ by default).  If the given value is less than
     ‘0’ a *note ValueError: 202. is raised.

     Changed in version 3.10: Removed the 'loop' parameter.

     The preferred way to use a Semaphore is an *note async with: 5d8.
     statement:

          sem = asyncio.Semaphore(10)

          # ... later
          async with sem:
              # work with shared resource

     which is equivalent to:

          sem = asyncio.Semaphore(10)

          # ... later
          await sem.acquire()
          try:
              # work with shared resource
          finally:
              sem.release()

      -- Method: async acquire ()

          Acquire a semaphore.

          If the internal counter is greater than zero, decrement it by
          one and return ‘True’ immediately.  If it is zero, wait until
          a *note release(): 3505. is called and return ‘True’.

      -- Method: locked ()

          Returns ‘True’ if semaphore can not be acquired immediately.

      -- Method: release ()

          Release a semaphore, incrementing the internal counter by one.
          Can wake up a task waiting to acquire the semaphore.

          Unlike *note BoundedSemaphore: a84, ‘Semaphore’ allows making
          more ‘release()’ calls than ‘acquire()’ calls.


File: python.info,  Node: BoundedSemaphore,  Next: Barrier,  Prev: Semaphore,  Up: Synchronization Primitives

5.19.1.35 BoundedSemaphore
..........................

 -- Class: asyncio.BoundedSemaphore (value=1)

     A bounded semaphore object.  Not thread-safe.

     Bounded Semaphore is a version of *note Semaphore: a83. that raises
     a *note ValueError: 202. in *note release(): 3505. if it increases
     the internal counter above the initial 'value'.

     Changed in version 3.10: Removed the 'loop' parameter.


File: python.info,  Node: Barrier,  Prev: BoundedSemaphore,  Up: Synchronization Primitives

5.19.1.36 Barrier
.................

 -- Class: asyncio.Barrier (parties)

     A barrier object.  Not thread-safe.

     A barrier is a simple synchronization primitive that allows to
     block until 'parties' number of tasks are waiting on it.  Tasks can
     wait on the *note wait(): 3509. method and would be blocked until
     the specified number of tasks end up waiting on ‘wait()’.  At that
     point all of the waiting tasks would unblock simultaneously.

     *note async with: 5d8. can be used as an alternative to awaiting on
     *note wait(): 3509.

     The barrier can be reused any number of times.  Example:

          async def example_barrier():
             # barrier with 3 parties
             b = asyncio.Barrier(3)

             # create 2 new waiting tasks
             asyncio.create_task(b.wait())
             asyncio.create_task(b.wait())

             await asyncio.sleep(0)
             print(b)

             # The third .wait() call passes the barrier
             await b.wait()
             print(b)
             print("barrier passed")

             await asyncio.sleep(0)
             print(b)

          asyncio.run(example_barrier())

     Result of this example is:

          <asyncio.locks.Barrier object at 0x... [filling, waiters:2/3]>
          <asyncio.locks.Barrier object at 0x... [draining, waiters:0/3]>
          barrier passed
          <asyncio.locks.Barrier object at 0x... [filling, waiters:0/3]>

     Added in version 3.11.

      -- Method: async wait ()

          Pass the barrier.  When all the tasks party to the barrier
          have called this function, they are all unblocked
          simultaneously.

          When a waiting or blocked task in the barrier is cancelled,
          this task exits the barrier which stays in the same state.  If
          the state of the barrier is “filling”, the number of waiting
          task decreases by 1.

          The return value is an integer in the range of 0 to
          ‘parties-1’, different for each task.  This can be used to
          select a task to do some special housekeeping, e.g.:

               ...
               async with barrier as position:
                  if position == 0:
                     # Only one task prints this
                     print('End of *draining phase*')

          This method may raise a *note BrokenBarrierError: 605.
          exception if the barrier is broken or reset while a task is
          waiting.  It could raise a *note CancelledError: 1b8. if a
          task is cancelled.

      -- Method: async reset ()

          Return the barrier to the default, empty state.  Any tasks
          waiting on it will receive the *note BrokenBarrierError: 605.
          exception.

          If a barrier is broken it may be better to just leave it and
          create a new one.

      -- Method: async abort ()

          Put the barrier into a broken state.  This causes any active
          or future calls to *note wait(): 3509. to fail with the *note
          BrokenBarrierError: 605.  Use this for example if one of the
          tasks needs to abort, to avoid infinite waiting tasks.

      -- Attribute: parties

          The number of tasks required to pass the barrier.

      -- Attribute: n_waiting

          The number of tasks currently waiting in the barrier while
          filling.

      -- Attribute: broken

          A boolean that is ‘True’ if the barrier is in the broken
          state.

 -- Exception: asyncio.BrokenBarrierError

     This exception, a subclass of *note RuntimeError: 195, is raised
     when the *note Barrier: 604. object is reset or broken.

__________________________________________________________________

Changed in version 3.9: Acquiring a lock using ‘await lock’ or ‘yield
from lock’ and/or *note with: 5d5. statement (‘with await lock’, ‘with
(yield from lock)’) was removed.  Use ‘async with lock’ instead.


File: python.info,  Node: Subprocesses,  Next: Queues,  Prev: Synchronization Primitives,  Up: asyncio — Asynchronous I/O

5.19.1.37 Subprocesses
......................

'Source code:' Lib/asyncio/subprocess.py(1),
Lib/asyncio/base_subprocess.py(2)

__________________________________________________________________

This section describes high-level async/await asyncio APIs to create and
manage subprocesses.  Here’s an example of how asyncio can run a shell
command and obtain its result:

     import asyncio

     async def run(cmd):
         proc = await asyncio.create_subprocess_shell(
             cmd,
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE)

         stdout, stderr = await proc.communicate()

         print(f'[{cmd!r} exited with {proc.returncode}]')
         if stdout:
             print(f'[stdout]\n{stdout.decode()}')
         if stderr:
             print(f'[stderr]\n{stderr.decode()}')

     asyncio.run(run('ls /zzz'))

will print:

     ['ls /zzz' exited with 1]
     [stderr]
     ls: /zzz: No such file or directory

Because all asyncio subprocess functions are asynchronous and asyncio
provides many tools to work with such functions, it is easy to execute
and monitor multiple subprocesses in parallel.  It is indeed trivial to
modify the above example to run several commands simultaneously:

     async def main():
         await asyncio.gather(
             run('ls /zzz'),
             run('sleep 1; echo "hello"'))

     asyncio.run(main())

See also the *note Examples: 3514. subsection.

* Menu:

* Creating Subprocesses::
* Constants: Constants<7>.
* Interacting with Subprocesses::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/subprocess.py

   (2) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/base_subprocess.py


File: python.info,  Node: Creating Subprocesses,  Next: Constants<7>,  Up: Subprocesses

5.19.1.38 Creating Subprocesses
...............................

 -- Function: async asyncio.create_subprocess_exec (program, *args,
          stdin=None, stdout=None, stderr=None, limit=None, **kwds)

     Create a subprocess.

     The 'limit' argument sets the buffer limit for *note StreamReader:
     15b6. wrappers for *note stdout: 3516. and *note stderr: 3517. (if
     *note subprocess.PIPE: ba5. is passed to 'stdout' and 'stderr'
     arguments).

     Return a *note Process: 3518. instance.

     See the documentation of *note loop.subprocess_exec(): 3519. for
     other parameters.

     If the process object is garbage collected while the process is
     still running, the child process will be killed.

     Changed in version 3.10: Removed the 'loop' parameter.

 -- Function: async asyncio.create_subprocess_shell (cmd, stdin=None,
          stdout=None, stderr=None, limit=None, **kwds)

     Run the 'cmd' shell command.

     The 'limit' argument sets the buffer limit for *note StreamReader:
     15b6. wrappers for *note stdout: 3516. and *note stderr: 3517. (if
     *note subprocess.PIPE: ba5. is passed to 'stdout' and 'stderr'
     arguments).

     Return a *note Process: 3518. instance.

     See the documentation of *note loop.subprocess_shell(): 351a. for
     other parameters.

     If the process object is garbage collected while the process is
     still running, the child process will be killed.

          Important: It is the application’s responsibility to ensure
          that all whitespace and special characters are quoted
          appropriately to avoid shell injection(1) vulnerabilities.
          The *note shlex.quote(): 27d. function can be used to properly
          escape whitespace and special shell characters in strings that
          are going to be used to construct shell commands.

     Changed in version 3.10: Removed the 'loop' parameter.

     Note: Subprocesses are available for Windows if a *note
     ProactorEventLoop: 60c. is used.  See *note Subprocess Support on
     Windows: 351b. for details.

See also
........

asyncio also has the following 'low-level' APIs to work with
subprocesses: *note loop.subprocess_exec(): 3519, *note
loop.subprocess_shell(): 351a, *note loop.connect_read_pipe(): 351c,
*note loop.connect_write_pipe(): 351d, as well as the *note Subprocess
Transports: 351e. and *note Subprocess Protocols: 351f.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Shell_injection#Shell_injection


File: python.info,  Node: Constants<7>,  Next: Interacting with Subprocesses,  Prev: Creating Subprocesses,  Up: Subprocesses

5.19.1.39 Constants
...................

 -- Data: asyncio.subprocess.PIPE

     Can be passed to the 'stdin', 'stdout' or 'stderr' parameters.

     If 'PIPE' is passed to 'stdin' argument, the *note Process.stdin:
     3522. attribute will point to a *note StreamWriter: 180f. instance.

     If 'PIPE' is passed to 'stdout' or 'stderr' arguments, the *note
     Process.stdout: 3516. and *note Process.stderr: 3517. attributes
     will point to *note StreamReader: 15b6. instances.

 -- Data: asyncio.subprocess.STDOUT

     Special value that can be used as the 'stderr' argument and
     indicates that standard error should be redirected into standard
     output.

 -- Data: asyncio.subprocess.DEVNULL

     Special value that can be used as the 'stdin', 'stdout' or 'stderr'
     argument to process creation functions.  It indicates that the
     special file *note os.devnull: 1bc3. will be used for the
     corresponding subprocess stream.


File: python.info,  Node: Interacting with Subprocesses,  Prev: Constants<7>,  Up: Subprocesses

5.19.1.40 Interacting with Subprocesses
.......................................

Both *note create_subprocess_exec(): a86. and *note
create_subprocess_shell(): a87. functions return instances of the
'Process' class.  'Process' is a high-level wrapper that allows
communicating with subprocesses and watching for their completion.

 -- Class: asyncio.subprocess.Process

     An object that wraps OS processes created by the *note
     create_subprocess_exec(): a86. and *note create_subprocess_shell():
     a87. functions.

     This class is designed to have a similar API to the *note
     subprocess.Popen: 199. class, but there are some notable
     differences:

        * unlike Popen, Process instances do not have an equivalent to
          the *note poll(): 3429. method;

        * the *note communicate(): 183f. and *note wait(): 3526. methods
          don’t have a 'timeout' parameter: use the *note wait_for():
          602. function;

        * the *note Process.wait(): 3526. method is asynchronous,
          whereas *note subprocess.Popen.wait(): d0b. method is
          implemented as a blocking busy loop;

        * the 'universal_newlines' parameter is not supported.

     This class is *note not thread safe: 34be.

     See also the *note Subprocess and Threads: 3527. section.

      -- Method: async wait ()

          Wait for the child process to terminate.

          Set and return the *note returncode: 3528. attribute.

               Note: This method can deadlock when using ‘stdout=PIPE’
               or ‘stderr=PIPE’ and the child process generates so much
               output that it blocks waiting for the OS pipe buffer to
               accept more data.  Use the *note communicate(): 183f.
               method when using pipes to avoid this condition.

      -- Method: async communicate (input=None)

          Interact with process:

            1. send data to 'stdin' (if 'input' is not ‘None’);

            2. closes 'stdin';

            3. read data from 'stdout' and 'stderr', until EOF is
               reached;

            4. wait for process to terminate.

          The optional 'input' argument is the data (*note bytes: 1c2.
          object) that will be sent to the child process.

          Return a tuple ‘(stdout_data, stderr_data)’.

          If either *note BrokenPipeError: 109a. or *note
          ConnectionResetError: 109d. exception is raised when writing
          'input' into 'stdin', the exception is ignored.  This
          condition occurs when the process exits before all data are
          written into 'stdin'.

          If it is desired to send data to the process’ 'stdin', the
          process needs to be created with ‘stdin=PIPE’.  Similarly, to
          get anything other than ‘None’ in the result tuple, the
          process has to be created with ‘stdout=PIPE’ and/or
          ‘stderr=PIPE’ arguments.

          Note, that the data read is buffered in memory, so do not use
          this method if the data size is large or unlimited.

          Changed in version 3.12: 'stdin' gets closed when ‘input=None’
          too.

      -- Method: send_signal (signal)

          Sends the signal 'signal' to the child process.

               Note: On Windows, *note SIGTERM: 142d. is an alias for
               *note terminate(): 3529.  ‘CTRL_C_EVENT’ and
               ‘CTRL_BREAK_EVENT’ can be sent to processes started with
               a 'creationflags' parameter which includes
               ‘CREATE_NEW_PROCESS_GROUP’.

      -- Method: terminate ()

          Stop the child process.

          On POSIX systems this method sends *note SIGTERM: 142d. to the
          child process.

          On Windows the Win32 API function ‘TerminateProcess()’ is
          called to stop the child process.

      -- Method: kill ()

          Kill the child process.

          On POSIX systems this method sends *note SIGKILL: b74. to the
          child process.

          On Windows this method is an alias for *note terminate():
          3529.

      -- Attribute: stdin

          Standard input stream (*note StreamWriter: 180f.) or ‘None’ if
          the process was created with ‘stdin=None’.

      -- Attribute: stdout

          Standard output stream (*note StreamReader: 15b6.) or ‘None’
          if the process was created with ‘stdout=None’.

      -- Attribute: stderr

          Standard error stream (*note StreamReader: 15b6.) or ‘None’ if
          the process was created with ‘stderr=None’.

          Warning: Use the *note communicate(): 183f. method rather than
          *note process.stdin.write(): 3522, *note await
          process.stdout.read(): 3516. or *note await
          process.stderr.read(): 3517.  This avoids deadlocks due to
          streams pausing reading or writing and blocking the child
          process.

      -- Attribute: pid

          Process identification number (PID).

          Note that for processes created by the *note
          create_subprocess_shell(): a87. function, this attribute is
          the PID of the spawned shell.

      -- Attribute: returncode

          Return code of the process when it exits.

          A ‘None’ value indicates that the process has not terminated
          yet.

          For processes created with *note create_subprocess_exec():
          a86, a negative value ‘-N’ indicates that the child was
          terminated by signal ‘N’ (POSIX only).

          For processes created with *note create_subprocess_shell():
          a87, the return code reflects the exit status of the shell
          itself (e.g.  ‘/bin/sh’), which may map signals to codes such
          as ‘128+N’.  See the documentation of the shell (for example,
          the Bash manual’s Exit Status) for details.

* Menu:

* Subprocess and Threads::
* Examples: Examples<16>.


File: python.info,  Node: Subprocess and Threads,  Next: Examples<16>,  Up: Interacting with Subprocesses

5.19.1.41 Subprocess and Threads
................................

Standard asyncio event loop supports running subprocesses from different
threads by default.

On Windows subprocesses are provided by *note ProactorEventLoop: 60c.
only (default), *note SelectorEventLoop: 60b. has no subprocess support.

On UNIX 'child watchers' are used for subprocess finish waiting, see
*note Process Watchers: 352d. for more info.

Changed in version 3.8: UNIX switched to use *note ThreadedChildWatcher:
47e. for spawning subprocesses from different threads without any
limitation.

Spawning a subprocess with 'inactive' current child watcher raises *note
RuntimeError: 195.

Note that alternative event loop implementations might have own
limitations; please refer to their documentation.

See also
........

The *note Concurrency and multithreading in asyncio: 34be. section.


File: python.info,  Node: Examples<16>,  Prev: Subprocess and Threads,  Up: Interacting with Subprocesses

5.19.1.42 Examples
..................

An example using the *note Process: 3518. class to control a subprocess
and the *note StreamReader: 15b6. class to read from its standard
output.  The subprocess is created by the *note
create_subprocess_exec(): a86. function:

     import asyncio
     import sys

     async def get_date():
         code = 'import datetime as dt; print(dt.datetime.now())'

         # Create the subprocess; redirect the standard output
         # into a pipe.
         proc = await asyncio.create_subprocess_exec(
             sys.executable, '-c', code,
             stdout=asyncio.subprocess.PIPE)

         # Read one line of output.
         data = await proc.stdout.readline()
         line = data.decode('ascii').rstrip()

         # Wait for the subprocess exit.
         await proc.wait()
         return line

     date = asyncio.run(get_date())
     print(f"Current date: {date}")

See also the *note same example: 352f. written using low-level APIs.


File: python.info,  Node: Queues,  Next: Exceptions<13>,  Prev: Subprocesses,  Up: asyncio — Asynchronous I/O

5.19.1.43 Queues
................

'Source code:' Lib/asyncio/queues.py(1)

__________________________________________________________________

asyncio queues are designed to be similar to classes of the *note queue:
b6. module.  Although asyncio queues are not thread-safe, they are
designed to be used specifically in async/await code.

Note that methods of asyncio queues don’t have a 'timeout' parameter;
use *note asyncio.wait_for(): 602. function to do queue operations with
a timeout.

See also the *note Examples: 3533. section below.

* Menu:

* Queue::
* Priority Queue::
* LIFO Queue::
* Exceptions: Exceptions<12>.
* Examples: Examples<17>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/asyncio/queues.py


File: python.info,  Node: Queue,  Next: Priority Queue,  Up: Queues

5.19.1.44 Queue
...............

 -- Class: asyncio.Queue (maxsize=0)

     A first in, first out (FIFO) queue.

     If 'maxsize' is less than or equal to zero, the queue size is
     infinite.  If it is an integer greater than ‘0’, then ‘await put()’
     blocks when the queue reaches 'maxsize' until an item is removed by
     *note get(): 3535.

     Unlike the standard library threading *note queue: b6, the size of
     the queue is always known and can be returned by calling the *note
     qsize(): 3536. method.

     Changed in version 3.10: Removed the 'loop' parameter.

     This class is *note not thread safe: 34be.

      -- Attribute: maxsize

          Number of items allowed in the queue.

      -- Method: empty ()

          Return ‘True’ if the queue is empty, ‘False’ otherwise.

      -- Method: full ()

          Return ‘True’ if there are *note maxsize: 3537. items in the
          queue.

          If the queue was initialized with ‘maxsize=0’ (the default),
          then ‘full()’ never returns ‘True’.

      -- Method: async get ()

          Remove and return an item from the queue.  If queue is empty,
          wait until an item is available.

          Raises *note QueueShutDown: 1b1. if the queue has been shut
          down and is empty, or if the queue has been shut down
          immediately.

      -- Method: get_nowait ()

          Return an item if one is immediately available, else raise
          *note QueueEmpty: 353b.

      -- Method: async join ()

          Block until all items in the queue have been received and
          processed.

          The count of unfinished tasks goes up whenever an item is
          added to the queue.  The count goes down whenever a consumer
          coroutine calls *note task_done(): df7. to indicate that the
          item was retrieved and all work on it is complete.  When the
          count of unfinished tasks drops to zero, ‘join()’ unblocks.

      -- Method: async put (item)

          Put an item into the queue.  If the queue is full, wait until
          a free slot is available before adding the item.

          Raises *note QueueShutDown: 1b1. if the queue has been shut
          down.

      -- Method: put_nowait (item)

          Put an item into the queue without blocking.

          If no free slot is immediately available, raise *note
          QueueFull: 353e.

      -- Method: qsize ()

          Return the number of items in the queue.

      -- Method: shutdown (immediate=False)

          Put a ‘Queue’ instance into a shutdown mode.

          The queue can no longer grow.  Future calls to *note put():
          353c. raise *note QueueShutDown: 1b1.  Currently blocked
          callers of ‘put()’ will be unblocked and will raise
          ‘QueueShutDown’ in the formerly awaiting task.

          If 'immediate' is false (the default), the queue can be wound
          down normally with *note get(): 3535. calls to extract tasks
          that have already been loaded.

          And if *note task_done(): df7. is called for each remaining
          task, a pending *note join(): df6. will be unblocked normally.

          Once the queue is empty, future calls to *note get(): 3535.
          will raise *note QueueShutDown: 1b1.

          If 'immediate' is true, the queue is terminated immediately.
          The queue is drained to be completely empty and the count of
          unfinished tasks is reduced by the number of tasks drained.
          If unfinished tasks is zero, callers of *note join(): df6. are
          unblocked.  Also, blocked callers of *note get(): 3535. are
          unblocked and will raise *note QueueShutDown: 1b1. because the
          queue is empty.

          Use caution when using *note join(): df6. with 'immediate' set
          to true.  This unblocks the join even when no work has been
          done on the tasks, violating the usual invariant for joining a
          queue.

          Added in version 3.13.

      -- Method: task_done ()

          Indicate that a formerly enqueued work item is complete.

          Used by queue consumers.  For each *note get(): 3535. used to
          fetch a work item, a subsequent call to ‘task_done()’ tells
          the queue that the processing on the work item is complete.

          If a *note join(): df6. is currently blocking, it will resume
          when all items have been processed (meaning that a
          ‘task_done()’ call was received for every item that had been
          *note put(): 353c. into the queue).

          Raises *note ValueError: 202. if called more times than there
          were items placed in the queue.


File: python.info,  Node: Priority Queue,  Next: LIFO Queue,  Prev: Queue,  Up: Queues

5.19.1.45 Priority Queue
........................

 -- Class: asyncio.PriorityQueue

     A variant of *note Queue: a85.; retrieves entries in priority order
     (lowest first).

     Entries are typically tuples of the form ‘(priority_number, data)’.


File: python.info,  Node: LIFO Queue,  Next: Exceptions<12>,  Prev: Priority Queue,  Up: Queues

5.19.1.46 LIFO Queue
....................

 -- Class: asyncio.LifoQueue

     A variant of *note Queue: a85. that retrieves most recently added
     entries first (last in, first out).


File: python.info,  Node: Exceptions<12>,  Next: Examples<17>,  Prev: LIFO Queue,  Up: Queues

5.19.1.47 Exceptions
....................

 -- Exception: asyncio.QueueEmpty

     This exception is raised when the *note get_nowait(): 353a. method
     is called on an empty queue.

 -- Exception: asyncio.QueueFull

     Exception raised when the *note put_nowait(): 353d. method is
     called on a queue that has reached its 'maxsize'.

 -- Exception: asyncio.QueueShutDown

     Exception raised when *note put(): 353c. or *note get(): 3535. is
     called on a queue which has been shut down.

     Added in version 3.13.


File: python.info,  Node: Examples<17>,  Prev: Exceptions<12>,  Up: Queues

5.19.1.48 Examples
..................

Queues can be used to distribute workload between several concurrent
tasks:

     import asyncio
     import random
     import time


     async def worker(name, queue):
         while True:
             # Get a "work item" out of the queue.
             sleep_for = await queue.get()

             # Sleep for the "sleep_for" seconds.
             await asyncio.sleep(sleep_for)

             # Notify the queue that the "work item" has been processed.
             queue.task_done()

             print(f'{name} has slept for {sleep_for:.2f} seconds')


     async def main():
         # Create a queue that we will use to store our "workload".
         queue = asyncio.Queue()

         # Generate random timings and put them into the queue.
         total_sleep_time = 0
         for _ in range(20):
             sleep_for = random.uniform(0.05, 1.0)
             total_sleep_time += sleep_for
             queue.put_nowait(sleep_for)

         # Create three worker tasks to process the queue concurrently.
         tasks = []
         for i in range(3):
             task = asyncio.create_task(worker(f'worker-{i}', queue))
             tasks.append(task)

         # Wait until the queue is fully processed.
         started_at = time.monotonic()
         await queue.join()
         total_slept_for = time.monotonic() - started_at

         # Cancel our worker tasks.
         for task in tasks:
             task.cancel()
         # Wait until all worker tasks are cancelled.
         await asyncio.gather(*tasks, return_exceptions=True)

         print('====')
         print(f'3 workers slept in parallel for {total_slept_for:.2f} seconds')
         print(f'total expected sleep time: {total_sleep_time:.2f} seconds')


     asyncio.run(main())


File: python.info,  Node: Exceptions<13>,  Next: Event loop,  Prev: Queues,  Up: asyncio — Asynchronous I/O

5.19.1.49 Exceptions
....................

'Source code:' Lib/asyncio/exceptions.py(1)

__________________________________________________________________

 -- Exception: asyncio.TimeoutError

     A deprecated alias of ‘TimeoutError’, raised when the operation has
     exceeded the given deadline.

     Changed in version 3.11: This class was made an alias of
     ‘TimeoutError’.

 -- Exception: asyncio.CancelledError

     The operation has been cancelled.

     This exception can be caught to perform custom operations when
     asyncio Tasks are cancelled.  In almost all situations the
     exception must be re-raised.

     Changed in version 3.8: ‘CancelledError’ is now a subclass of *note
     BaseException: 5be. rather than *note Exception: 9e5.

 -- Exception: asyncio.InvalidStateError

     Invalid internal state of *note Task: 1be. or *note Future: bec.

     Can be raised in situations like setting a result value for a
     'Future' object that already has a result value set.

 -- Exception: asyncio.SendfileNotAvailableError

     The “sendfile” syscall is not available for the given socket or
     file type.

     A subclass of *note RuntimeError: 195.

 -- Exception: asyncio.IncompleteReadError

     The requested read operation did not complete fully.

     Raised by the *note asyncio stream APIs: 348f.

     This exception is a subclass of *note EOFError: 1321.

      -- Attribute: expected

          The total number (*note int: 257.) of expected bytes.

      -- Attribute: partial

          A string of *note bytes: 1c2. read before the end of stream
          was reached.

 -- Exception: asyncio.LimitOverrunError

     Reached the buffer size limit while looking for a separator.

     Raised by the *note asyncio stream APIs: 348f.

      -- Attribute: consumed

          The total number of to be consumed bytes.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/exceptions.py


File: python.info,  Node: Event loop,  Next: Futures,  Prev: Exceptions<13>,  Up: asyncio — Asynchronous I/O

5.19.1.50 Event loop
....................

'Source code:' Lib/asyncio/events.py(1), Lib/asyncio/base_events.py(2)

__________________________________________________________________

Preface
.......

The event loop is the core of every asyncio application.  Event loops
run asynchronous tasks and callbacks, perform network IO operations, and
run subprocesses.

Application developers should typically use the high-level asyncio
functions, such as *note asyncio.run(): 47f, and should rarely need to
reference the loop object or call its methods.  This section is intended
mostly for authors of lower-level code, libraries, and frameworks, who
need finer control over the event loop behavior.

Obtaining the Event Loop
........................

The following low-level functions can be used to get, set, or create an
event loop:

 -- Function: asyncio.get_running_loop ()

     Return the running event loop in the current OS thread.

     Raise a *note RuntimeError: 195. if there is no running event loop.

     This function can only be called from a coroutine or a callback.

     Added in version 3.7.

 -- Function: asyncio.get_event_loop ()

     Get the current event loop.

     When called from a coroutine or a callback (e.g.  scheduled with
     call_soon or similar API), this function will always return the
     running event loop.

     If there is no running event loop set, the function will return the
     result of the ‘get_event_loop_policy().get_event_loop()’ call.

     Because this function has rather complex behavior (especially when
     custom event loop policies are in use), using the *note
     get_running_loop(): b24. function is preferred to
     ‘get_event_loop()’ in coroutines and callbacks.

     As noted above, consider using the higher-level *note
     asyncio.run(): 47f. function, instead of using these lower level
     functions to manually create and close an event loop.

     Deprecated since version 3.12: Deprecation warning is emitted if
     there is no current event loop.  In some future Python release this
     will become an error.

 -- Function: asyncio.set_event_loop (loop)

     Set 'loop' as the current event loop for the current OS thread.

 -- Function: asyncio.new_event_loop ()

     Create and return a new event loop object.

Note that the behaviour of *note get_event_loop(): 2c2, *note
set_event_loop(): 18fa, and *note new_event_loop(): 349c. functions can
be altered by *note setting a custom event loop policy: 354f.

Contents
........

This documentation page contains the following sections:

   * The *note Event Loop Methods: 3550. section is the reference
     documentation of the event loop APIs;

   * The *note Callback Handles: 3551. section documents the *note
     Handle: 1c35. and *note TimerHandle: 1880. instances which are
     returned from scheduling methods such as *note loop.call_soon():
     b1d. and *note loop.call_later(): b1f.;

   * The *note Server Objects: 3552. section documents types returned
     from event loop methods like *note loop.create_server(): b2c.;

   * The *note Event Loop Implementations: 3553. section documents the
     *note SelectorEventLoop: 60b. and *note ProactorEventLoop: 60c.
     classes;

   * The *note Examples: 3554. section showcases how to work with some
     event loop APIs.

* Menu:

* Event loop methods::
* Callback handles::
* Server objects::
* Event loop implementations::
* Examples: Examples<18>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/asyncio/events.py

   (2) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/base_events.py


File: python.info,  Node: Event loop methods,  Next: Callback handles,  Up: Event loop

5.19.1.51 Event loop methods
............................

Event loops have 'low-level' APIs for the following:

* Menu:

* Running and stopping the loop::
* Scheduling callbacks::
* Scheduling delayed callbacks::
* Creating futures and tasks::
* Opening network connections::
* Creating network servers::
* Transferring files::
* TLS upgrade::
* Watching file descriptors::
* Working with socket objects directly::
* DNS::
* Working with pipes::
* Unix signals::
* Executing code in thread or process pools::
* Error handling API::
* Enabling debug mode::
* Running subprocesses::


File: python.info,  Node: Running and stopping the loop,  Next: Scheduling callbacks,  Up: Event loop methods

5.19.1.52 Running and stopping the loop
.......................................

 -- Method: loop.run_until_complete (future)

     Run until the 'future' (an instance of *note Future: bec.) has
     completed.

     If the argument is a *note coroutine object: 348e. it is implicitly
     scheduled to run as a *note asyncio.Task: 1be.

     Return the Future’s result or raise its exception.

 -- Method: loop.run_forever ()

     Run the event loop until *note stop(): c9e. is called.

     If *note stop(): c9e. is called before ‘run_forever()’ is called,
     the loop will poll the I/O selector once with a timeout of zero,
     run all callbacks scheduled in response to I/O events (and those
     that were already scheduled), and then exit.

     If *note stop(): c9e. is called while ‘run_forever()’ is running,
     the loop will run the current batch of callbacks and then exit.
     Note that new callbacks scheduled by callbacks will not run in this
     case; instead, they will run the next time ‘run_forever()’ or *note
     run_until_complete(): c99. is called.

 -- Method: loop.stop ()

     Stop the event loop.

 -- Method: loop.is_running ()

     Return ‘True’ if the event loop is currently running.

 -- Method: loop.is_closed ()

     Return ‘True’ if the event loop was closed.

 -- Method: loop.close ()

     Close the event loop.

     The loop must not be running when this function is called.  Any
     pending callbacks will be discarded.

     This method clears all queues and shuts down the executor, but does
     not wait for the executor to finish.

     This method is idempotent and irreversible.  No other methods
     should be called after the event loop is closed.

 -- Method: async loop.shutdown_asyncgens ()

     Schedule all currently open *note asynchronous generator: 21f2.
     objects to close with an *note aclose(): 8e1. call.  After calling
     this method, the event loop will issue a warning if a new
     asynchronous generator is iterated.  This should be used to
     reliably finalize all scheduled asynchronous generators.

     Note that there is no need to call this function when *note
     asyncio.run(): 47f. is used.

     Example:

          try:
              loop.run_forever()
          finally:
              loop.run_until_complete(loop.shutdown_asyncgens())
              loop.close()

     Added in version 3.6.

 -- Method: async loop.shutdown_default_executor (timeout=None)

     Schedule the closure of the default executor and wait for it to
     join all of the threads in the *note ThreadPoolExecutor: 745.  Once
     this method has been called, using the default executor with *note
     loop.run_in_executor(): 8f2. will raise a *note RuntimeError: 195.

     The 'timeout' parameter specifies the amount of time (in *note
     float: 2f7. seconds) the executor will be given to finish joining.
     With the default, ‘None’, the executor is allowed an unlimited
     amount of time.

     If the 'timeout' is reached, a *note RuntimeWarning: 1bd. is
     emitted and the default executor is terminated without waiting for
     its threads to finish joining.

          Note: Do not call this method when using *note asyncio.run():
          47f, as the latter handles default executor shutdown
          automatically.

     Added in version 3.9.

     Changed in version 3.12: Added the 'timeout' parameter.


File: python.info,  Node: Scheduling callbacks,  Next: Scheduling delayed callbacks,  Prev: Running and stopping the loop,  Up: Event loop methods

5.19.1.53 Scheduling callbacks
..............................

 -- Method: loop.call_soon (callback, *args, context=None)

     Schedule the 'callback' *note callback: 2aee. to be called with
     'args' arguments at the next iteration of the event loop.

     Return an instance of *note asyncio.Handle: 1c35, which can be used
     later to cancel the callback.

     Callbacks are called in the order in which they are registered.
     Each callback will be called exactly once.

     The optional keyword-only 'context' argument specifies a custom
     *note contextvars.Context: 15dd. for the 'callback' to run in.
     Callbacks use the current context when no 'context' is provided.

     Unlike *note call_soon_threadsafe(): b1e, this method is not
     thread-safe.

 -- Method: loop.call_soon_threadsafe (callback, *args, context=None)

     A thread-safe variant of *note call_soon(): b1d.  When scheduling
     callbacks from another thread, this function 'must' be used, since
     ‘call_soon()’ is not thread-safe.

     This function is safe to be called from a reentrant context or
     signal handler, however, it is not safe or fruitful to use the
     returned handle in such contexts.

     Raises *note RuntimeError: 195. if called on a loop that’s been
     closed.  This can happen on a secondary thread when the main
     application is shutting down.

     See the *note concurrency and multithreading: 34be. section of the
     documentation.

     Changed in version 3.7: The 'context' keyword-only parameter was
     added.  See PEP 567(1) for more details.

     Note: Most *note asyncio: a. scheduling functions don’t allow
     passing keyword arguments.  To do that, use *note
     functools.partial(): 417.:

          # will schedule "print("Hello", flush=True)"
          loop.call_soon(
              functools.partial(print, "Hello", flush=True))

     Using partial objects is usually more convenient than using
     lambdas, as asyncio can render partial objects better in debug and
     error messages.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0567/


File: python.info,  Node: Scheduling delayed callbacks,  Next: Creating futures and tasks,  Prev: Scheduling callbacks,  Up: Event loop methods

5.19.1.54 Scheduling delayed callbacks
......................................

Event loop provides mechanisms to schedule callback functions to be
called at some point in the future.  Event loop uses monotonic clocks to
track time.

 -- Method: loop.call_later (delay, callback, *args, context=None)

     Schedule 'callback' to be called after the given 'delay' number of
     seconds (can be either an int or a float).

     An instance of *note asyncio.TimerHandle: 1880. is returned which
     can be used to cancel the callback.

     'callback' will be called exactly once.  If two callbacks are
     scheduled for exactly the same time, the order in which they are
     called is undefined.

     The optional positional 'args' will be passed to the callback when
     it is called.  Use *note functools.partial(): 417. *note to pass
     keyword arguments: 355b. to 'callback'.

     An optional keyword-only 'context' argument allows specifying a
     custom *note contextvars.Context: 15dd. for the 'callback' to run
     in.  The current context is used when no 'context' is provided.

          Note: For performance, callbacks scheduled with
          ‘loop.call_later()’ may run up to one clock-resolution early
          (see ‘time.get_clock_info('monotonic').resolution’).

     Changed in version 3.7: The 'context' keyword-only parameter was
     added.  See PEP 567(1) for more details.

     Changed in version 3.8: In Python 3.7 and earlier with the default
     event loop implementation, the 'delay' could not exceed one day.
     This has been fixed in Python 3.8.

 -- Method: loop.call_at (when, callback, *args, context=None)

     Schedule 'callback' to be called at the given absolute timestamp
     'when' (an int or a float), using the same time reference as *note
     loop.time(): 355e.

     This method’s behavior is the same as *note call_later(): b1f.

     An instance of *note asyncio.TimerHandle: 1880. is returned which
     can be used to cancel the callback.

          Note: For performance, callbacks scheduled with
          ‘loop.call_at()’ may run up to one clock-resolution early (see
          ‘time.get_clock_info('monotonic').resolution’).

     Changed in version 3.7: The 'context' keyword-only parameter was
     added.  See PEP 567(2) for more details.

     Changed in version 3.8: In Python 3.7 and earlier with the default
     event loop implementation, the difference between 'when' and the
     current time could not exceed one day.  This has been fixed in
     Python 3.8.

 -- Method: loop.time ()

     Return the current time, as a *note float: 2f7. value, according to
     the event loop’s internal monotonic clock.

     Note: 
     Changed in version 3.8: In Python 3.7 and earlier timeouts
     (relative 'delay' or absolute 'when') should not exceed one day.
     This has been fixed in Python 3.8.

See also
........

The *note asyncio.sleep(): a7e. function.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0567/

   (2) https://peps.python.org/pep-0567/


File: python.info,  Node: Creating futures and tasks,  Next: Opening network connections,  Prev: Scheduling delayed callbacks,  Up: Event loop methods

5.19.1.55 Creating futures and tasks
....................................

 -- Method: loop.create_future ()

     Create an *note asyncio.Future: bec. object attached to the event
     loop.

     This is the preferred way to create Futures in asyncio.  This lets
     third-party event loops provide alternative implementations of the
     Future object (with better performance or instrumentation).

     Added in version 3.5.2.

 -- Method: loop.create_task (coro, *, name=None, context=None,
          **kwargs)

     Schedule the execution of *note coroutine: 348e. 'coro'.  Return a
     *note Task: 1be. object.

     Third-party event loops can use their own subclass of *note Task:
     1be. for interoperability.  In this case, the result type is a
     subclass of ‘Task’.

     The full function signature is largely the same as that of the
     *note Task: 1be. constructor (or factory) - all of the keyword
     arguments to this function are passed through to that interface,
     except 'name', or 'context' if it is ‘None’.

     If the 'name' argument is provided and not ‘None’, it is set as the
     name of the task using *note Task.set_name(): 9e8.

     An optional keyword-only 'context' argument allows specifying a
     custom *note contextvars.Context: 15dd. for the 'coro' to run in.
     The current context copy is created when no 'context' is provided.

     Changed in version 3.8: Added the 'name' parameter.

     Changed in version 3.11: Added the 'context' parameter.

     Changed in version 3.13.3: Added ‘kwargs’ which passes on arbitrary
     extra parameters, including ‘name’ and ‘context’.

     Changed in version 3.13.4: Rolled back the change that passes on
     'name' and 'context' (if it is None), while still passing on other
     arbitrary keyword arguments (to avoid breaking backwards
     compatibility with 3.13.3).

 -- Method: loop.set_task_factory (factory)

     Set a task factory that will be used by *note loop.create_task():
     1c0.

     If 'factory' is ‘None’ the default task factory will be set.
     Otherwise, 'factory' must be a 'callable' with the signature
     matching ‘(loop, coro, **kwargs)’, where 'loop' is a reference to
     the active event loop, and 'coro' is a coroutine object.  The
     callable must pass on all 'kwargs', and return a *note
     asyncio.Task: 1be.-compatible object.

     Changed in version 3.13.3: Required that all 'kwargs' are passed on
     to *note asyncio.Task: 1be.

     Changed in version 3.13.4: 'name' is no longer passed to task
     factories.  'context' is no longer passed to task factories if it
     is ‘None’.

 -- Method: loop.get_task_factory ()

     Return a task factory or ‘None’ if the default one is in use.


File: python.info,  Node: Opening network connections,  Next: Creating network servers,  Prev: Creating futures and tasks,  Up: Event loop methods

5.19.1.56 Opening network connections
.....................................

 -- Method: async loop.create_connection (protocol_factory, host=None,
          port=None, *, ssl=None, family=0, proto=0, flags=0, sock=None,
          local_addr=None, server_hostname=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          happy_eyeballs_delay=None, interleave=None, all_errors=False)

     Open a streaming transport connection to a given address specified
     by 'host' and 'port'.

     The socket family can be either *note AF_INET: 1953. or *note
     AF_INET6: 1954. depending on 'host' (or the 'family' argument, if
     provided).

     The socket type will be *note SOCK_STREAM: 133c.

     'protocol_factory' must be a callable returning an *note asyncio
     protocol: 3561. implementation.

     This method will try to establish the connection in the background.
     When successful, it returns a ‘(transport, protocol)’ pair.

     The chronological synopsis of the underlying operation is as
     follows:

       1. The connection is established and a *note transport: 3562. is
          created for it.

       2. 'protocol_factory' is called without arguments and is expected
          to return a *note protocol: 3561. instance.

       3. The protocol instance is coupled with the transport by calling
          its *note connection_made(): 3563. method.

       4. A ‘(transport, protocol)’ tuple is returned on success.

     The created transport is an implementation-dependent bidirectional
     stream.

     Other arguments:

        * 'ssl': if given and not false, a SSL/TLS transport is created
          (by default a plain TCP transport is created).  If 'ssl' is a
          *note ssl.SSLContext: 294. object, this context is used to
          create the transport; if 'ssl' is *note True: c2d, a default
          context returned from *note ssl.create_default_context(): 155.
          is used.

          See also
          ........

          *note SSL/TLS security considerations: 3564.

        * 'server_hostname' sets or overrides the hostname that the
          target server’s certificate will be matched against.  Should
          only be passed if 'ssl' is not ‘None’.  By default the value
          of the 'host' argument is used.  If 'host' is empty, there is
          no default and you must pass a value for 'server_hostname'.
          If 'server_hostname' is an empty string, hostname matching is
          disabled (which is a serious security risk, allowing for
          potential man-in-the-middle attacks).

        * 'family', 'proto', 'flags' are the optional address family,
          protocol and flags to be passed through to getaddrinfo() for
          'host' resolution.  If given, these should all be integers
          from the corresponding *note socket: cc. module constants.

        * 'happy_eyeballs_delay', if given, enables Happy Eyeballs for
          this connection.  It should be a floating-point number
          representing the amount of time in seconds to wait for a
          connection attempt to complete, before starting the next
          attempt in parallel.  This is the “Connection Attempt Delay”
          as defined in RFC 8305(1).  A sensible default value
          recommended by the RFC is ‘0.25’ (250 milliseconds).

        * 'interleave' controls address reordering when a host name
          resolves to multiple IP addresses.  If ‘0’ or unspecified, no
          reordering is done, and addresses are tried in the order
          returned by *note getaddrinfo(): c34.  If a positive integer
          is specified, the addresses are interleaved by address family,
          and the given integer is interpreted as “First Address Family
          Count” as defined in RFC 8305(2).  The default is ‘0’ if
          'happy_eyeballs_delay' is not specified, and ‘1’ if it is.

        * 'sock', if given, should be an existing, already connected
          *note socket.socket: dcf. object to be used by the transport.
          If 'sock' is given, none of 'host', 'port', 'family', 'proto',
          'flags', 'happy_eyeballs_delay', 'interleave' and 'local_addr'
          should be specified.

               Note: The 'sock' argument transfers ownership of the
               socket to the transport created.  To close the socket,
               call the transport’s *note close(): 3565. method.

        * 'local_addr', if given, is a ‘(local_host, local_port)’ tuple
          used to bind the socket locally.  The 'local_host' and
          'local_port' are looked up using ‘getaddrinfo()’, similarly to
          'host' and 'port'.

        * 'ssl_handshake_timeout' is (for a TLS connection) the time in
          seconds to wait for the TLS handshake to complete before
          aborting the connection.  ‘60.0’ seconds if ‘None’ (default).

        * 'ssl_shutdown_timeout' is the time in seconds to wait for the
          SSL shutdown to complete before aborting the connection.
          ‘30.0’ seconds if ‘None’ (default).

        * 'all_errors' determines what exceptions are raised when a
          connection cannot be created.  By default, only a single
          ‘Exception’ is raised: the first exception if there is only
          one or all errors have same message, or a single ‘OSError’
          with the error messages combined.  When ‘all_errors’ is
          ‘True’, an ‘ExceptionGroup’ will be raised containing all
          exceptions (even if there is only one).

     Changed in version 3.5: Added support for SSL/TLS in *note
     ProactorEventLoop: 60c.

     Changed in version 3.6: The socket option *note socket.TCP_NODELAY:
     b91. is set by default for all TCP connections.

     Changed in version 3.7: Added the 'ssl_handshake_timeout'
     parameter.

     Changed in version 3.8: Added the 'happy_eyeballs_delay' and
     'interleave' parameters.

     Happy Eyeballs Algorithm: Success with Dual-Stack Hosts.  When a
     server’s IPv4 path and protocol are working, but the server’s IPv6
     path and protocol are not working, a dual-stack client application
     experiences significant connection delay compared to an IPv4-only
     client.  This is undesirable because it causes the dual-stack
     client to have a worse user experience.  This document specifies
     requirements for algorithms that reduce this user-visible delay and
     provides an algorithm.

     For more information:
     ‘https://datatracker.ietf.org/doc/html/rfc6555’

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

     Changed in version 3.12: 'all_errors' was added.

     See also
     ........

     The *note open_connection(): b31. function is a high-level
     alternative API. It returns a pair of (*note StreamReader: 15b6,
     *note StreamWriter: 180f.) that can be used directly in async/await
     code.

 -- Method: async loop.create_datagram_endpoint (protocol_factory,
          local_addr=None, remote_addr=None, *, family=0, proto=0,
          flags=0, reuse_port=None, allow_broadcast=None, sock=None)

     Create a datagram connection.

     The socket family can be either *note AF_INET: 1953, *note
     AF_INET6: 1954, or *note AF_UNIX: 1955, depending on 'host' (or the
     'family' argument, if provided).

     The socket type will be *note SOCK_DGRAM: 133b.

     'protocol_factory' must be a callable returning a *note protocol:
     3561. implementation.

     A tuple of ‘(transport, protocol)’ is returned on success.

     Other arguments:

        * 'local_addr', if given, is a ‘(local_host, local_port)’ tuple
          used to bind the socket locally.  The 'local_host' and
          'local_port' are looked up using *note getaddrinfo(): c34.

               Note: On Windows, when using the proactor event loop with
               ‘local_addr=None’, an *note OSError: 41a. with
               ‘errno.WSAEINVAL’ will be raised when running it.

        * 'remote_addr', if given, is a ‘(remote_host, remote_port)’
          tuple used to connect the socket to a remote address.  The
          'remote_host' and 'remote_port' are looked up using *note
          getaddrinfo(): c34.

        * 'family', 'proto', 'flags' are the optional address family,
          protocol and flags to be passed through to *note
          getaddrinfo(): c34. for 'host' resolution.  If given, these
          should all be integers from the corresponding *note socket:
          cc. module constants.

        * 'reuse_port' tells the kernel to allow this endpoint to be
          bound to the same port as other existing endpoints are bound
          to, so long as they all set this flag when being created.
          This option is not supported on Windows and some Unixes.  If
          the *note socket.SO_REUSEPORT: b91. constant is not defined
          then this capability is unsupported.

        * 'allow_broadcast' tells the kernel to allow this endpoint to
          send messages to the broadcast address.

        * 'sock' can optionally be specified in order to use a
          preexisting, already connected, *note socket.socket: dcf.
          object to be used by the transport.  If specified,
          'local_addr' and 'remote_addr' should be omitted (must be
          *note None: 678.).

               Note: The 'sock' argument transfers ownership of the
               socket to the transport created.  To close the socket,
               call the transport’s *note close(): 3565. method.

     See *note UDP echo client protocol: 3566. and *note UDP echo server
     protocol: 3567. examples.

     Changed in version 3.4.4: The 'family', 'proto', 'flags',
     'reuse_address', 'reuse_port', 'allow_broadcast', and 'sock'
     parameters were added.

     Changed in version 3.8: Added support for Windows.

     Changed in version 3.8.1: The 'reuse_address' parameter is no
     longer supported, as using *note socket.SO_REUSEADDR: b91. poses a
     significant security concern for UDP. Explicitly passing
     ‘reuse_address=True’ will raise an exception.

     When multiple processes with differing UIDs assign sockets to an
     identical UDP socket address with ‘SO_REUSEADDR’, incoming packets
     can become randomly distributed among the sockets.

     For supported platforms, 'reuse_port' can be used as a replacement
     for similar functionality.  With 'reuse_port', *note
     socket.SO_REUSEPORT: b91. is used instead, which specifically
     prevents processes with differing UIDs from assigning sockets to
     the same socket address.

     Changed in version 3.11: The 'reuse_address' parameter, disabled
     since Python 3.8.1, 3.7.6 and 3.6.10, has been entirely removed.

 -- Method: async loop.create_unix_connection (protocol_factory,
          path=None, *, ssl=None, sock=None, server_hostname=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

     Create a Unix connection.

     The socket family will be *note AF_UNIX: 1955.; socket type will be
     *note SOCK_STREAM: 133c.

     A tuple of ‘(transport, protocol)’ is returned on success.

     'path' is the name of a Unix domain socket and is required, unless
     a 'sock' parameter is specified.  Abstract Unix sockets, *note str:
     44f, *note bytes: 1c2, and *note Path: 229. paths are supported.

     See the documentation of the *note loop.create_connection(): 606.
     method for information about arguments to this method.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.7: Added the 'ssl_handshake_timeout'
     parameter.  The 'path' parameter can now be a *note path-like
     object: 2a0.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc8305.html

   (2) https://datatracker.ietf.org/doc/html/rfc8305.html


File: python.info,  Node: Creating network servers,  Next: Transferring files,  Prev: Opening network connections,  Up: Event loop methods

5.19.1.57 Creating network servers
..................................

 -- Method: async loop.create_server (protocol_factory, host=None,
          port=None, *, family=socket.AF_UNSPEC,
          flags=socket.AI_PASSIVE, sock=None, backlog=100, ssl=None,
          reuse_address=None, reuse_port=None, keep_alive=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          start_serving=True)

     Create a TCP server (socket type *note SOCK_STREAM: 133c.)
     listening on 'port' of the 'host' address.

     Returns a *note Server: b2b. object.

     Arguments:

        * 'protocol_factory' must be a callable returning a *note
          protocol: 3561. implementation.

        * The 'host' parameter can be set to several types which
          determine where the server would be listening:

             - If 'host' is a string, the TCP server is bound to a
               single network interface specified by 'host'.

             - If 'host' is a sequence of strings, the TCP server is
               bound to all network interfaces specified by the
               sequence.

             - If 'host' is an empty string or ‘None’, all interfaces
               are assumed and a list of multiple sockets will be
               returned (most likely one for IPv4 and another one for
               IPv6).

        * The 'port' parameter can be set to specify which port the
          server should listen on.  If ‘0’ or ‘None’ (the default), a
          random unused port will be selected (note that if 'host'
          resolves to multiple network interfaces, a different random
          port will be selected for each interface).

        * 'family' can be set to either *note socket.AF_INET: 1953. or
          *note AF_INET6: 1954. to force the socket to use IPv4 or IPv6.
          If not set, the 'family' will be determined from host name
          (defaults to *note AF_UNSPEC: 3569.).

        * 'flags' is a bitmask for *note getaddrinfo(): c34.

        * 'sock' can optionally be specified in order to use a
          preexisting socket object.  If specified, 'host' and 'port'
          must not be specified.

               Note: The 'sock' argument transfers ownership of the
               socket to the server created.  To close the socket, call
               the server’s *note close(): 34d3. method.

        * 'backlog' is the maximum number of queued connections passed
          to *note listen(): e92. (defaults to 100).

        * 'ssl' can be set to an *note SSLContext: 294. instance to
          enable TLS over the accepted connections.

        * 'reuse_address' tells the kernel to reuse a local socket in
          ‘TIME_WAIT’ state, without waiting for its natural timeout to
          expire.  If not specified will automatically be set to ‘True’
          on Unix.

        * 'reuse_port' tells the kernel to allow this endpoint to be
          bound to the same port as other existing endpoints are bound
          to, so long as they all set this flag when being created.
          This option is not supported on Windows.

        * 'keep_alive' set to ‘True’ keeps connections active by
          enabling the periodic transmission of messages.

     Changed in version 3.13: Added the 'keep_alive' parameter.

        * 'ssl_handshake_timeout' is (for a TLS server) the time in
          seconds to wait for the TLS handshake to complete before
          aborting the connection.  ‘60.0’ seconds if ‘None’ (default).

        * 'ssl_shutdown_timeout' is the time in seconds to wait for the
          SSL shutdown to complete before aborting the connection.
          ‘30.0’ seconds if ‘None’ (default).

        * 'start_serving' set to ‘True’ (the default) causes the created
          server to start accepting connections immediately.  When set
          to ‘False’, the user should await on *note
          Server.start_serving(): b2d. or *note Server.serve_forever():
          b2e. to make the server to start accepting connections.

     Changed in version 3.5: Added support for SSL/TLS in *note
     ProactorEventLoop: 60c.

     Changed in version 3.5.1: The 'host' parameter can be a sequence of
     strings.

     Changed in version 3.6: Added 'ssl_handshake_timeout' and
     'start_serving' parameters.  The socket option *note
     socket.TCP_NODELAY: b91. is set by default for all TCP connections.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

     See also
     ........

     The *note start_server(): b32. function is a higher-level
     alternative API that returns a pair of *note StreamReader: 15b6.
     and *note StreamWriter: 180f. that can be used in an async/await
     code.

 -- Method: async loop.create_unix_server (protocol_factory, path=None,
          *, sock=None, backlog=100, ssl=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None,
          start_serving=True, cleanup_socket=True)

     Similar to *note loop.create_server(): b2c. but works with the
     *note AF_UNIX: 1955. socket family.

     'path' is the name of a Unix domain socket, and is required, unless
     a 'sock' argument is provided.  Abstract Unix sockets, *note str:
     44f, *note bytes: 1c2, and *note Path: 229. paths are supported.

     If 'cleanup_socket' is true then the Unix socket will automatically
     be removed from the filesystem when the server is closed, unless
     the socket has been replaced after the server has been created.

     See the documentation of the *note loop.create_server(): b2c.
     method for information about arguments to this method.

     *note Availability: 1ef7.: Unix.

     Changed in version 3.7: Added the 'ssl_handshake_timeout' and
     'start_serving' parameters.  The 'path' parameter can now be a
     *note Path: 229. object.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.

     Changed in version 3.13: Added the 'cleanup_socket' parameter.

 -- Method: async loop.connect_accepted_socket (protocol_factory, sock,
          *, ssl=None, ssl_handshake_timeout=None,
          ssl_shutdown_timeout=None)

     Wrap an already accepted connection into a transport/protocol pair.

     This method can be used by servers that accept connections outside
     of asyncio but that use asyncio to handle them.

     Parameters:

        * 'protocol_factory' must be a callable returning a *note
          protocol: 3561. implementation.

        * 'sock' is a preexisting socket object returned from *note
          socket.accept: dd0.

               Note: The 'sock' argument transfers ownership of the
               socket to the transport created.  To close the socket,
               call the transport’s *note close(): 3565. method.

        * 'ssl' can be set to an *note SSLContext: 294. to enable SSL
          over the accepted connections.

        * 'ssl_handshake_timeout' is (for an SSL connection) the time in
          seconds to wait for the SSL handshake to complete before
          aborting the connection.  ‘60.0’ seconds if ‘None’ (default).

        * 'ssl_shutdown_timeout' is the time in seconds to wait for the
          SSL shutdown to complete before aborting the connection.
          ‘30.0’ seconds if ‘None’ (default).

     Returns a ‘(transport, protocol)’ pair.

     Added in version 3.5.3.

     Changed in version 3.7: Added the 'ssl_handshake_timeout'
     parameter.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.


File: python.info,  Node: Transferring files,  Next: TLS upgrade,  Prev: Creating network servers,  Up: Event loop methods

5.19.1.58 Transferring files
............................

 -- Method: async loop.sendfile (transport, file, offset=0, count=None,
          *, fallback=True)

     Send a 'file' over a 'transport'.  Return the total number of bytes
     sent.

     The method uses high-performance *note os.sendfile(): b28. if
     available.

     'file' must be a regular file object opened in binary mode.

     'offset' tells from where to start reading the file.  If specified,
     'count' is the total number of bytes to transmit as opposed to
     sending the file until EOF is reached.  File position is always
     updated, even when this method raises an error, and *note
     file.tell(): 13f9. can be used to obtain the actual number of bytes
     sent.

     'fallback' set to ‘True’ makes asyncio to manually read and send
     the file when the platform does not support the sendfile system
     call (e.g.  Windows or SSL socket on Unix).

     Raise *note SendfileNotAvailableError: 3549. if the system does not
     support the 'sendfile' syscall and 'fallback' is ‘False’.

     Added in version 3.7.


File: python.info,  Node: TLS upgrade,  Next: Watching file descriptors,  Prev: Transferring files,  Up: Event loop methods

5.19.1.59 TLS upgrade
.....................

 -- Method: async loop.start_tls (transport, protocol, sslcontext, *,
          server_side=False, server_hostname=None,
          ssl_handshake_timeout=None, ssl_shutdown_timeout=None)

     Upgrade an existing transport-based connection to TLS.

     Create a TLS coder/decoder instance and insert it between the
     'transport' and the 'protocol'.  The coder/decoder implements both
     'transport'-facing protocol and 'protocol'-facing transport.

     Return the created two-interface instance.  After 'await', the
     'protocol' must stop using the original 'transport' and communicate
     with the returned object only because the coder caches
     'protocol'-side data and sporadically exchanges extra TLS session
     packets with 'transport'.

     In some situations (e.g.  when the passed transport is already
     closing) this may return ‘None’.

     Parameters:

        * 'transport' and 'protocol' instances that methods like *note
          create_server(): b2c. and *note create_connection(): 606.
          return.

        * 'sslcontext': a configured instance of *note SSLContext: 294.

        * 'server_side' pass ‘True’ when a server-side connection is
          being upgraded (like the one created by *note create_server():
          b2c.).

        * 'server_hostname': sets or overrides the host name that the
          target server’s certificate will be matched against.

        * 'ssl_handshake_timeout' is (for a TLS connection) the time in
          seconds to wait for the TLS handshake to complete before
          aborting the connection.  ‘60.0’ seconds if ‘None’ (default).

        * 'ssl_shutdown_timeout' is the time in seconds to wait for the
          SSL shutdown to complete before aborting the connection.
          ‘30.0’ seconds if ‘None’ (default).

     Added in version 3.7.

     Changed in version 3.11: Added the 'ssl_shutdown_timeout'
     parameter.


File: python.info,  Node: Watching file descriptors,  Next: Working with socket objects directly,  Prev: TLS upgrade,  Up: Event loop methods

5.19.1.60 Watching file descriptors
...................................

 -- Method: loop.add_reader (fd, callback, *args)

     Start monitoring the 'fd' file descriptor for read availability and
     invoke 'callback' with the specified arguments once 'fd' is
     available for reading.

     Any preexisting callback registered for 'fd' is cancelled and
     replaced by 'callback'.

 -- Method: loop.remove_reader (fd)

     Stop monitoring the 'fd' file descriptor for read availability.
     Returns ‘True’ if 'fd' was previously being monitored for reads.

 -- Method: loop.add_writer (fd, callback, *args)

     Start monitoring the 'fd' file descriptor for write availability
     and invoke 'callback' with the specified arguments 'args' once 'fd'
     is available for writing.

     Any preexisting callback registered for 'fd' is cancelled and
     replaced by 'callback'.

     Use *note functools.partial(): 417. *note to pass keyword
     arguments: 355b. to 'callback'.

 -- Method: loop.remove_writer (fd)

     Stop monitoring the 'fd' file descriptor for write availability.
     Returns ‘True’ if 'fd' was previously being monitored for writes.

See also *note Platform Support: 3571. section for some limitations of
these methods.


File: python.info,  Node: Working with socket objects directly,  Next: DNS,  Prev: Watching file descriptors,  Up: Event loop methods

5.19.1.61 Working with socket objects directly
..............................................

In general, protocol implementations that use transport-based APIs such
as *note loop.create_connection(): 606. and *note loop.create_server():
b2c. are faster than implementations that work with sockets directly.
However, there are some use cases when performance is not critical, and
working with *note socket: dcf. objects directly is more convenient.

 -- Method: async loop.sock_recv (sock, nbytes)

     Receive up to 'nbytes' from 'sock'.  Asynchronous version of *note
     socket.recv(): dd2.

     Return the received data as a bytes object.

     'sock' must be a non-blocking socket.

     Changed in version 3.7: Even though this method was always
     documented as a coroutine method, releases before Python 3.7
     returned a *note Future: bec.  Since Python 3.7 this is an ‘async
     def’ method.

 -- Method: async loop.sock_recv_into (sock, buf)

     Receive data from 'sock' into the 'buf' buffer.  Modeled after the
     blocking *note socket.recv_into(): 1367. method.

     Return the number of bytes written to the buffer.

     'sock' must be a non-blocking socket.

     Added in version 3.7.

 -- Method: async loop.sock_recvfrom (sock, bufsize)

     Receive a datagram of up to 'bufsize' from 'sock'.  Asynchronous
     version of *note socket.recvfrom(): dd3.

     Return a tuple of (received data, remote address).

     'sock' must be a non-blocking socket.

     Added in version 3.11.

 -- Method: async loop.sock_recvfrom_into (sock, buf, nbytes=0)

     Receive a datagram of up to 'nbytes' from 'sock' into 'buf'.
     Asynchronous version of *note socket.recvfrom_into(): 1368.

     Return a tuple of (number of bytes received, remote address).

     'sock' must be a non-blocking socket.

     Added in version 3.11.

 -- Method: async loop.sock_sendall (sock, data)

     Send 'data' to the 'sock' socket.  Asynchronous version of *note
     socket.sendall(): dd6.

     This method continues to send to the socket until either all data
     in 'data' has been sent or an error occurs.  ‘None’ is returned on
     success.  On error, an exception is raised.  Additionally, there is
     no way to determine how much data, if any, was successfully
     processed by the receiving end of the connection.

     'sock' must be a non-blocking socket.

     Changed in version 3.7: Even though the method was always
     documented as a coroutine method, before Python 3.7 it returned a
     *note Future: bec.  Since Python 3.7, this is an ‘async def’
     method.

 -- Method: async loop.sock_sendto (sock, data, address)

     Send a datagram from 'sock' to 'address'.  Asynchronous version of
     *note socket.sendto(): dd7.

     Return the number of bytes sent.

     'sock' must be a non-blocking socket.

     Added in version 3.11.

 -- Method: async loop.sock_connect (sock, address)

     Connect 'sock' to a remote socket at 'address'.

     Asynchronous version of *note socket.connect(): dd1.

     'sock' must be a non-blocking socket.

     Changed in version 3.5.2: ‘address’ no longer needs to be resolved.
     ‘sock_connect’ will try to check if the 'address' is already
     resolved by calling *note socket.inet_pton(): 96c.  If not, *note
     loop.getaddrinfo(): c34. will be used to resolve the 'address'.

     See also
     ........

     *note loop.create_connection(): 606. and *note
     asyncio.open_connection(): b31.

 -- Method: async loop.sock_accept (sock)

     Accept a connection.  Modeled after the blocking *note
     socket.accept(): dd0. method.

     The socket must be bound to an address and listening for
     connections.  The return value is a pair ‘(conn, address)’ where
     'conn' is a 'new' socket object usable to send and receive data on
     the connection, and 'address' is the address bound to the socket on
     the other end of the connection.

     'sock' must be a non-blocking socket.

     Changed in version 3.7: Even though the method was always
     documented as a coroutine method, before Python 3.7 it returned a
     *note Future: bec.  Since Python 3.7, this is an ‘async def’
     method.

     See also
     ........

     *note loop.create_server(): b2c. and *note start_server(): b32.

 -- Method: async loop.sock_sendfile (sock, file, offset=0, count=None,
          *, fallback=True)

     Send a file using high-performance *note os.sendfile: b28. if
     possible.  Return the total number of bytes sent.

     Asynchronous version of *note socket.sendfile(): e91.

     'sock' must be a non-blocking *note socket.SOCK_STREAM: 133c. *note
     socket: dcf.

     'file' must be a regular file object open in binary mode.

     'offset' tells from where to start reading the file.  If specified,
     'count' is the total number of bytes to transmit as opposed to
     sending the file until EOF is reached.  File position is always
     updated, even when this method raises an error, and *note
     file.tell(): 13f9. can be used to obtain the actual number of bytes
     sent.

     'fallback', when set to ‘True’, makes asyncio manually read and
     send the file when the platform does not support the sendfile
     syscall (e.g.  Windows or SSL socket on Unix).

     Raise *note SendfileNotAvailableError: 3549. if the system does not
     support 'sendfile' syscall and 'fallback' is ‘False’.

     'sock' must be a non-blocking socket.

     Added in version 3.7.


File: python.info,  Node: DNS,  Next: Working with pipes,  Prev: Working with socket objects directly,  Up: Event loop methods

5.19.1.62 DNS
.............

 -- Method: async loop.getaddrinfo (host, port, *, family=0, type=0,
          proto=0, flags=0)

     Asynchronous version of *note socket.getaddrinfo(): 15ba.

 -- Method: async loop.getnameinfo (sockaddr, flags=0)

     Asynchronous version of *note socket.getnameinfo(): 17d3.

     Note: Both 'getaddrinfo' and 'getnameinfo' internally utilize their
     synchronous versions through the loop’s default thread pool
     executor.  When this executor is saturated, these methods may
     experience delays, which higher-level networking libraries may
     report as increased timeouts.  To mitigate this, consider using a
     custom executor for other user tasks, or setting a default executor
     with a larger number of workers.

Changed in version 3.7: Both 'getaddrinfo' and 'getnameinfo' methods
were always documented to return a coroutine, but prior to Python 3.7
they were, in fact, returning *note asyncio.Future: bec. objects.
Starting with Python 3.7 both methods are coroutines.


File: python.info,  Node: Working with pipes,  Next: Unix signals,  Prev: DNS,  Up: Event loop methods

5.19.1.63 Working with pipes
............................

 -- Method: async loop.connect_read_pipe (protocol_factory, pipe)

     Register the read end of 'pipe' in the event loop.

     'protocol_factory' must be a callable returning an *note asyncio
     protocol: 3561. implementation.

     'pipe' is a *note file-like object: 1208.

     Return pair ‘(transport, protocol)’, where 'transport' supports the
     *note ReadTransport: 3575. interface and 'protocol' is an object
     instantiated by the 'protocol_factory'.

     With *note SelectorEventLoop: 60b. event loop, the 'pipe' is set to
     non-blocking mode.

 -- Method: async loop.connect_write_pipe (protocol_factory, pipe)

     Register the write end of 'pipe' in the event loop.

     'protocol_factory' must be a callable returning an *note asyncio
     protocol: 3561. implementation.

     'pipe' is *note file-like object: 1208.

     Return pair ‘(transport, protocol)’, where 'transport' supports
     *note WriteTransport: 3576. interface and 'protocol' is an object
     instantiated by the 'protocol_factory'.

     With *note SelectorEventLoop: 60b. event loop, the 'pipe' is set to
     non-blocking mode.

     Note: *note SelectorEventLoop: 60b. does not support the above
     methods on Windows.  Use *note ProactorEventLoop: 60c. instead for
     Windows.

See also
........

The *note loop.subprocess_exec(): 3519. and *note
loop.subprocess_shell(): 351a. methods.


File: python.info,  Node: Unix signals,  Next: Executing code in thread or process pools,  Prev: Working with pipes,  Up: Event loop methods

5.19.1.64 Unix signals
......................

 -- Method: loop.add_signal_handler (signum, callback, *args)

     Set 'callback' as the handler for the 'signum' signal, passing
     'args' as positional arguments.

     The callback will be invoked by 'loop', along with other queued
     callbacks and runnable coroutines of that event loop.  Unlike
     signal handlers registered using *note signal.signal(): 1178, a
     callback registered with this function is allowed to interact with
     the event loop.

     Raise *note ValueError: 202. if the signal number is invalid or
     uncatchable.  Raise *note RuntimeError: 195. if there is a problem
     setting up the handler.

     Use *note functools.partial(): 417. *note to pass keyword
     arguments: 355b. to 'callback'.

     Like *note signal.signal(): 1178, this function must be invoked in
     the main thread.

 -- Method: loop.remove_signal_handler (sig)

     Remove the handler for the 'sig' signal.

     Return ‘True’ if the signal handler was removed, or ‘False’ if no
     handler was set for the given signal.

     *note Availability: 1ef7.: Unix.

See also
........

The *note signal: c6. module.


File: python.info,  Node: Executing code in thread or process pools,  Next: Error handling API,  Prev: Unix signals,  Up: Event loop methods

5.19.1.65 Executing code in thread or process pools
...................................................

 -- Method: awaitable loop.run_in_executor (executor, func, *args)

     Arrange for 'func' to be called in the specified executor passing
     'args' as positional arguments.

     The 'executor' argument should be an *note
     concurrent.futures.Executor: 33dd. instance.  The default executor
     is used if 'executor' is ‘None’.  The default executor can be set
     by *note loop.set_default_executor(): 746, otherwise, a *note
     concurrent.futures.ThreadPoolExecutor: 745. will be
     lazy-initialized and used by *note run_in_executor(): 8f2. if
     needed.

     Example:

          import asyncio
          import concurrent.futures

          def blocking_io():
              # File operations (such as logging) can block the
              # event loop: run them in a thread pool.
              with open('/dev/urandom', 'rb') as f:
                  return f.read(100)

          def cpu_bound():
              # CPU-bound operations will block the event loop:
              # in general it is preferable to run them in a
              # process pool.
              return sum(i * i for i in range(10 ** 7))

          async def main():
              loop = asyncio.get_running_loop()

              ## Options:

              # 1. Run in the default loop's executor:
              result = await loop.run_in_executor(
                  None, blocking_io)
              print('default thread pool', result)

              # 2. Run in a custom thread pool:
              with concurrent.futures.ThreadPoolExecutor() as pool:
                  result = await loop.run_in_executor(
                      pool, blocking_io)
                  print('custom thread pool', result)

              # 3. Run in a custom process pool:
              with concurrent.futures.ProcessPoolExecutor() as pool:
                  result = await loop.run_in_executor(
                      pool, cpu_bound)
                  print('custom process pool', result)

          if __name__ == '__main__':
              asyncio.run(main())

     Note that the entry point guard (‘if __name__ == '__main__'’) is
     required for option 3 due to the peculiarities of *note
     multiprocessing: 94, which is used by *note ProcessPoolExecutor:
     8f7.  See *note Safe importing of main module: 33c6.

     This method returns a *note asyncio.Future: bec. object.

     Use *note functools.partial(): 417. *note to pass keyword
     arguments: 355b. to 'func'.

     Changed in version 3.5.3: ‘loop.run_in_executor()’ no longer
     configures the ‘max_workers’ of the thread pool executor it
     creates, instead leaving it up to the thread pool executor (*note
     ThreadPoolExecutor: 745.) to set the default.

 -- Method: loop.set_default_executor (executor)

     Set 'executor' as the default executor used by *note
     run_in_executor(): 8f2.  'executor' must be an instance of *note
     ThreadPoolExecutor: 745.

     Changed in version 3.11: 'executor' must be an instance of *note
     ThreadPoolExecutor: 745.


File: python.info,  Node: Error handling API,  Next: Enabling debug mode,  Prev: Executing code in thread or process pools,  Up: Event loop methods

5.19.1.66 Error handling API
............................

Allows customizing how exceptions are handled in the event loop.

 -- Method: loop.set_exception_handler (handler)

     Set 'handler' as the new event loop exception handler.

     If 'handler' is ‘None’, the default exception handler will be set.
     Otherwise, 'handler' must be a callable with the signature matching
     ‘(loop, context)’, where ‘loop’ is a reference to the active event
     loop, and ‘context’ is a ‘dict’ object containing the details of
     the exception (see *note call_exception_handler(): 357d.
     documentation for details about context).

     If the handler is called on behalf of a *note Task: 1be. or *note
     Handle: 1c35, it is run in the *note contextvars.Context: 15dd. of
     that task or callback handle.

     Changed in version 3.12: The handler may be called in the *note
     Context: 15dd. of the task or handle where the exception
     originated.

 -- Method: loop.get_exception_handler ()

     Return the current exception handler, or ‘None’ if no custom
     exception handler was set.

     Added in version 3.5.2.

 -- Method: loop.default_exception_handler (context)

     Default exception handler.

     This is called when an exception occurs and no exception handler is
     set.  This can be called by a custom exception handler that wants
     to defer to the default handler behavior.

     'context' parameter has the same meaning as in *note
     call_exception_handler(): 357d.

 -- Method: loop.call_exception_handler (context)

     Call the current event loop exception handler.

     'context' is a ‘dict’ object containing the following keys (new
     keys may be introduced in future Python versions):

        * ‘message’: Error message;

        * ‘exception’ (optional): Exception object;

        * ‘future’ (optional): *note asyncio.Future: bec. instance;

        * ‘task’ (optional): *note asyncio.Task: 1be. instance;

        * ‘handle’ (optional): *note asyncio.Handle: 1c35. instance;

        * ‘protocol’ (optional): *note Protocol: 3561. instance;

        * ‘transport’ (optional): *note Transport: 3562. instance;

        * ‘socket’ (optional): *note socket.socket: dcf. instance;

        * ‘source_traceback’ (optional): Traceback of the source;

        * ‘handle_traceback’ (optional): Traceback of the handle;

        * 
          ‘asyncgen’ (optional): Asynchronous generator that caused

               the exception.

          Note: This method should not be overloaded in subclassed event
          loops.  For custom exception handling, use the *note
          set_exception_handler(): 357c. method.


File: python.info,  Node: Enabling debug mode,  Next: Running subprocesses,  Prev: Error handling API,  Up: Event loop methods

5.19.1.67 Enabling debug mode
.............................

 -- Method: loop.get_debug ()

     Get the debug mode (*note bool: 46b.) of the event loop.

     The default value is ‘True’ if the environment variable *note
     PYTHONASYNCIODEBUG: 1ef1. is set to a non-empty string, ‘False’
     otherwise.

 -- Method: loop.set_debug (enabled: bool)

     Set the debug mode of the event loop.

     Changed in version 3.7: The new *note Python Development Mode: 1f8.
     can now also be used to enable the debug mode.

 -- Attribute: loop.slow_callback_duration

     This attribute can be used to set the minimum execution duration in
     seconds that is considered “slow”.  When debug mode is enabled,
     “slow” callbacks are logged.

     Default value is 100 milliseconds.

See also
........

The *note debug mode of asyncio: 1ef2.


File: python.info,  Node: Running subprocesses,  Prev: Enabling debug mode,  Up: Event loop methods

5.19.1.68 Running subprocesses
..............................

Methods described in this subsections are low-level.  In regular
async/await code consider using the high-level *note
asyncio.create_subprocess_shell(): a87. and *note
asyncio.create_subprocess_exec(): a86. convenience functions instead.

     Note: On Windows, the default event loop *note ProactorEventLoop:
     60c. supports subprocesses, whereas *note SelectorEventLoop: 60b.
     does not.  See *note Subprocess Support on Windows: 351b. for
     details.

 -- Method: async loop.subprocess_exec (protocol_factory, *args,
          stdin=subprocess.PIPE, stdout=subprocess.PIPE,
          stderr=subprocess.PIPE, **kwargs)

     Create a subprocess from one or more string arguments specified by
     'args'.

     'args' must be a list of strings represented by:

        * *note str: 44f.;

        * or *note bytes: 1c2, encoded to the *note filesystem encoding:
          298c.

     The first string specifies the program executable, and the
     remaining strings specify the arguments.  Together, string
     arguments form the ‘argv’ of the program.

     This is similar to the standard library *note subprocess.Popen:
     199. class called with ‘shell=False’ and the list of strings passed
     as the first argument; however, where ‘Popen’ takes a single
     argument which is list of strings, 'subprocess_exec' takes multiple
     string arguments.

     The 'protocol_factory' must be a callable returning a subclass of
     the *note asyncio.SubprocessProtocol: 3582. class.

     Other parameters:

        * 'stdin' can be any of these:

             * a file-like object

             * an existing file descriptor (a positive integer), for
               example those created with *note os.pipe(): 190a.

             * the *note subprocess.PIPE: ba5. constant (default) which
               will create a new pipe and connect it,

             * the value ‘None’ which will make the subprocess inherit
               the file descriptor from this process

             * the *note subprocess.DEVNULL: 1192. constant which
               indicates that the special *note os.devnull: 1bc3. file
               will be used

        * 'stdout' can be any of these:

             * a file-like object

             * the *note subprocess.PIPE: ba5. constant (default) which
               will create a new pipe and connect it,

             * the value ‘None’ which will make the subprocess inherit
               the file descriptor from this process

             * the *note subprocess.DEVNULL: 1192. constant which
               indicates that the special *note os.devnull: 1bc3. file
               will be used

        * 'stderr' can be any of these:

             * a file-like object

             * the *note subprocess.PIPE: ba5. constant (default) which
               will create a new pipe and connect it,

             * the value ‘None’ which will make the subprocess inherit
               the file descriptor from this process

             * the *note subprocess.DEVNULL: 1192. constant which
               indicates that the special *note os.devnull: 1bc3. file
               will be used

             * the *note subprocess.STDOUT: 33fd. constant which will
               connect the standard error stream to the process’
               standard output stream

        * All other keyword arguments are passed to *note
          subprocess.Popen: 199. without interpretation, except for
          'bufsize', 'universal_newlines', 'shell', 'text', 'encoding'
          and 'errors', which should not be specified at all.

          The ‘asyncio’ subprocess API does not support decoding the
          streams as text.  *note bytes.decode(): 8df. can be used to
          convert the bytes returned from the stream to text.

     If a file-like object passed as 'stdin', 'stdout' or 'stderr'
     represents a pipe, then the other side of this pipe should be
     registered with *note connect_write_pipe(): 351d. or *note
     connect_read_pipe(): 351c. for use with the event loop.

     See the constructor of the *note subprocess.Popen: 199. class for
     documentation on other arguments.

     Returns a pair of ‘(transport, protocol)’, where 'transport'
     conforms to the *note asyncio.SubprocessTransport: 3583. base class
     and 'protocol' is an object instantiated by the 'protocol_factory'.

     If the transport is closed or is garbage collected, the child
     process is killed if it is still running.

 -- Method: async loop.subprocess_shell (protocol_factory, cmd, *,
          stdin=subprocess.PIPE, stdout=subprocess.PIPE,
          stderr=subprocess.PIPE, **kwargs)

     Create a subprocess from 'cmd', which can be a *note str: 44f. or a
     *note bytes: 1c2. string encoded to the *note filesystem encoding:
     298c, using the platform’s “shell” syntax.

     This is similar to the standard library *note subprocess.Popen:
     199. class called with ‘shell=True’.

     The 'protocol_factory' must be a callable returning a subclass of
     the *note SubprocessProtocol: 3582. class.

     See *note subprocess_exec(): 3519. for more details about the
     remaining arguments.

     Returns a pair of ‘(transport, protocol)’, where 'transport'
     conforms to the *note SubprocessTransport: 3583. base class and
     'protocol' is an object instantiated by the 'protocol_factory'.

     If the transport is closed or is garbage collected, the child
     process is killed if it is still running.

     Note: It is the application’s responsibility to ensure that all
     whitespace and special characters are quoted appropriately to avoid
     shell injection(1) vulnerabilities.  The *note shlex.quote(): 27d.
     function can be used to properly escape whitespace and special
     characters in strings that are going to be used to construct shell
     commands.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Shell_injection#Shell_injection


File: python.info,  Node: Callback handles,  Next: Server objects,  Prev: Event loop methods,  Up: Event loop

5.19.1.69 Callback handles
..........................

 -- Class: asyncio.Handle

     A callback wrapper object returned by *note loop.call_soon(): b1d,
     *note loop.call_soon_threadsafe(): b1e.

      -- Method: get_context ()

          Return the *note contextvars.Context: 15dd. object associated
          with the handle.

          Added in version 3.12.

      -- Method: cancel ()

          Cancel the callback.  If the callback has already been
          canceled or executed, this method has no effect.

      -- Method: cancelled ()

          Return ‘True’ if the callback was cancelled.

          Added in version 3.7.

 -- Class: asyncio.TimerHandle

     A callback wrapper object returned by *note loop.call_later(): b1f,
     and *note loop.call_at(): b20.

     This class is a subclass of *note Handle: 1c35.

      -- Method: when ()

          Return a scheduled callback time as *note float: 2f7. seconds.

          The time is an absolute timestamp, using the same time
          reference as *note loop.time(): 355e.

          Added in version 3.7.


File: python.info,  Node: Server objects,  Next: Event loop implementations,  Prev: Callback handles,  Up: Event loop

5.19.1.70 Server objects
........................

Server objects are created by *note loop.create_server(): b2c, *note
loop.create_unix_server(): 1ae, *note start_server(): b32, and *note
start_unix_server(): 34d6. functions.

Do not instantiate the *note Server: b2b. class directly.

 -- Class: asyncio.Server

     'Server' objects are asynchronous context managers.  When used in
     an ‘async with’ statement, it’s guaranteed that the Server object
     is closed and not accepting new connections when the ‘async with’
     statement is completed:

          srv = await loop.create_server(...)

          async with srv:
              # some code

          # At this point, srv is closed and no longer accepts new connections.

     Changed in version 3.7: Server object is an asynchronous context
     manager since Python 3.7.

     Changed in version 3.11: This class was exposed publicly as
     ‘asyncio.Server’ in Python 3.9.11, 3.10.3 and 3.11.

      -- Method: close ()

          Stop serving: close listening sockets and set the *note
          sockets: c36. attribute to ‘None’.

          The sockets that represent existing incoming client
          connections are left open.

          The server is closed asynchronously; use the *note
          wait_closed(): 17d9. coroutine to wait until the server is
          closed (and no more connections are active).

      -- Method: close_clients ()

          Close all existing incoming client connections.

          Calls *note close(): 3565. on all associated transports.

          *note close(): 34d3. should be called before ‘close_clients()’
          when closing the server to avoid races with new clients
          connecting.

          Added in version 3.13.

      -- Method: abort_clients ()

          Close all existing incoming client connections immediately,
          without waiting for pending operations to complete.

          Calls *note abort(): 3586. on all associated transports.

          *note close(): 34d3. should be called before ‘abort_clients()’
          when closing the server to avoid races with new clients
          connecting.

          Added in version 3.13.

      -- Method: get_loop ()

          Return the event loop associated with the server object.

          Added in version 3.7.

      -- Method: async start_serving ()

          Start accepting connections.

          This method is idempotent, so it can be called when the server
          is already serving.

          The 'start_serving' keyword-only parameter to *note
          loop.create_server(): b2c. and *note asyncio.start_server():
          b32. allows creating a Server object that is not accepting
          connections initially.  In this case ‘Server.start_serving()’,
          or *note Server.serve_forever(): b2e. can be used to make the
          Server start accepting connections.

          Added in version 3.7.

      -- Method: async serve_forever ()

          Start accepting connections until the coroutine is cancelled.
          Cancellation of ‘serve_forever’ task causes the server to be
          closed.

          This method can be called if the server is already accepting
          connections.  Only one ‘serve_forever’ task can exist per one
          'Server' object.

          Example:

               async def client_connected(reader, writer):
                   # Communicate with the client with
                   # reader/writer streams.  For example:
                   await reader.readline()

               async def main(host, port):
                   srv = await asyncio.start_server(
                       client_connected, host, port)
                   await srv.serve_forever()

               asyncio.run(main('127.0.0.1', 0))

          Added in version 3.7.

      -- Method: is_serving ()

          Return ‘True’ if the server is accepting new connections.

          Added in version 3.7.

      -- Method: async wait_closed ()

          Wait until the *note close(): 34d3. method completes and all
          active connections have finished.

      -- Attribute: sockets

          List of socket-like objects, ‘asyncio.trsock.TransportSocket’,
          which the server is listening on.

          Changed in version 3.7: Prior to Python 3.7 ‘Server.sockets’
          used to return an internal list of server sockets directly.
          In 3.7 a copy of that list is returned.


File: python.info,  Node: Event loop implementations,  Next: Examples<18>,  Prev: Server objects,  Up: Event loop

5.19.1.71 Event loop implementations
....................................

asyncio ships with two different event loop implementations: *note
SelectorEventLoop: 60b. and *note ProactorEventLoop: 60c.

By default asyncio is configured to use *note EventLoop: 1806.

 -- Class: asyncio.SelectorEventLoop

     A subclass of *note AbstractEventLoop: 969. based on the *note
     selectors: c2. module.

     Uses the most efficient 'selector' available for the given
     platform.  It is also possible to manually configure the exact
     selector implementation to be used:

          import asyncio
          import selectors

          class MyPolicy(asyncio.DefaultEventLoopPolicy):
             def new_event_loop(self):
                selector = selectors.SelectSelector()
                return asyncio.SelectorEventLoop(selector)

          asyncio.set_event_loop_policy(MyPolicy())

     *note Availability: 1ef7.: Unix, Windows.

 -- Class: asyncio.ProactorEventLoop

     A subclass of *note AbstractEventLoop: 969. for Windows that uses
     “I/O Completion Ports” (IOCP).

     *note Availability: 1ef7.: Windows.

     See also
     ........

     MSDN documentation on I/O Completion Ports(1).

 -- Class: asyncio.EventLoop

          An alias to the most efficient available subclass of *note
          AbstractEventLoop: 969. for the given platform.

          It is an alias to *note SelectorEventLoop: 60b. on Unix and
          *note ProactorEventLoop: 60c. on Windows.

     Added in version 3.13.

 -- Class: asyncio.AbstractEventLoop

     Abstract base class for asyncio-compliant event loops.

     The *note Event loop methods: 3555. section lists all methods that
     an alternative implementation of ‘AbstractEventLoop’ should have
     defined.

   ---------- Footnotes ----------

   (1) 
https://learn.microsoft.com/windows/win32/fileio/i-o-completion-ports


File: python.info,  Node: Examples<18>,  Prev: Event loop implementations,  Up: Event loop

5.19.1.72 Examples
..................

Note that all examples in this section 'purposefully' show how to use
the low-level event loop APIs, such as *note loop.run_forever(): 3557.
and *note loop.call_soon(): b1d.  Modern asyncio applications rarely
need to be written this way; consider using the high-level functions
like *note asyncio.run(): 47f.

* Menu:

* Hello World with call_soon(): Hello World with call_soon.
* Display the current date with call_later(): Display the current date with call_later.
* Watch a file descriptor for read events::
* Set signal handlers for SIGINT and SIGTERM::


File: python.info,  Node: Hello World with call_soon,  Next: Display the current date with call_later,  Up: Examples<18>

5.19.1.73 Hello World with call_soon()
......................................

An example using the *note loop.call_soon(): b1d. method to schedule a
callback.  The callback displays ‘"Hello World"’ and then stops the
event loop:

     import asyncio

     def hello_world(loop):
         """A callback to print 'Hello World' and stop the event loop"""
         print('Hello World')
         loop.stop()

     loop = asyncio.new_event_loop()

     # Schedule a call to hello_world()
     loop.call_soon(hello_world, loop)

     # Blocking call interrupted by loop.stop()
     try:
         loop.run_forever()
     finally:
         loop.close()

See also
........

A similar *note Hello World: 348e. example created with a coroutine and
the *note run(): 47f. function.


File: python.info,  Node: Display the current date with call_later,  Next: Watch a file descriptor for read events,  Prev: Hello World with call_soon,  Up: Examples<18>

5.19.1.74 Display the current date with call_later()
....................................................

An example of a callback displaying the current date every second.  The
callback uses the *note loop.call_later(): b1f. method to reschedule
itself after 5 seconds, and then stops the event loop:

     import asyncio
     import datetime as dt

     def display_date(end_time, loop):
         print(dt.datetime.now())
         if (loop.time() + 1.0) < end_time:
             loop.call_later(1, display_date, end_time, loop)
         else:
             loop.stop()

     loop = asyncio.new_event_loop()

     # Schedule the first call to display_date()
     end_time = loop.time() + 5.0
     loop.call_soon(display_date, end_time, loop)

     # Blocking call interrupted by loop.stop()
     try:
         loop.run_forever()
     finally:
         loop.close()

See also
........

A similar *note current date: 34ad. example created with a coroutine and
the *note run(): 47f. function.


File: python.info,  Node: Watch a file descriptor for read events,  Next: Set signal handlers for SIGINT and SIGTERM,  Prev: Display the current date with call_later,  Up: Examples<18>

5.19.1.75 Watch a file descriptor for read events
.................................................

Wait until a file descriptor received some data using the *note
loop.add_reader(): 34f0. method and then close the event loop:

     import asyncio
     from socket import socketpair

     # Create a pair of connected file descriptors
     rsock, wsock = socketpair()

     loop = asyncio.new_event_loop()

     def reader():
         data = rsock.recv(100)
         print("Received:", data.decode())

         # We are done: unregister the file descriptor
         loop.remove_reader(rsock)

         # Stop the event loop
         loop.stop()

     # Register the file descriptor for read event
     loop.add_reader(rsock, reader)

     # Simulate the reception of data from the network
     loop.call_soon(wsock.send, 'abc'.encode())

     try:
         # Run the event loop
         loop.run_forever()
     finally:
         # We are done. Close sockets and the event loop.
         rsock.close()
         wsock.close()
         loop.close()

See also
........

   * A similar *note example: 34ee. using transports, protocols, and the
     *note loop.create_connection(): 606. method.

   * Another similar *note example: 34ec. using the high-level *note
     asyncio.open_connection(): b31. function and streams.


File: python.info,  Node: Set signal handlers for SIGINT and SIGTERM,  Prev: Watch a file descriptor for read events,  Up: Examples<18>

5.19.1.76 Set signal handlers for SIGINT and SIGTERM
....................................................

(This ‘signals’ example only works on Unix.)

Register handlers for signals *note SIGINT: 84a. and *note SIGTERM:
142d. using the *note loop.add_signal_handler(): 3578. method:

     import asyncio
     import functools
     import os
     import signal

     def ask_exit(signame, loop):
         print("got signal %s: exit" % signame)
         loop.stop()

     async def main():
         loop = asyncio.get_running_loop()

         for signame in {'SIGINT', 'SIGTERM'}:
             loop.add_signal_handler(
                 getattr(signal, signame),
                 functools.partial(ask_exit, signame, loop))

         await asyncio.sleep(3600)

     print("Event loop running for 1 hour, press Ctrl+C to interrupt.")
     print(f"pid {os.getpid()}: send SIGINT or SIGTERM to exit.")

     asyncio.run(main())


File: python.info,  Node: Futures,  Next: Transports and Protocols,  Prev: Event loop,  Up: asyncio — Asynchronous I/O

5.19.1.77 Futures
.................

'Source code:' Lib/asyncio/futures.py(1), Lib/asyncio/base_futures.py(2)

__________________________________________________________________

'Future' objects are used to bridge 'low-level callback-based code' with
high-level async/await code.

* Menu:

* Future Functions::
* Future Object::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/futures.py

   (2) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/base_futures.py


File: python.info,  Node: Future Functions,  Next: Future Object,  Up: Futures

5.19.1.78 Future Functions
..........................

 -- Function: asyncio.isfuture (obj)

     Return ‘True’ if 'obj' is either of:

        * an instance of *note asyncio.Future: bec,

        * an instance of *note asyncio.Task: 1be,

        * a Future-like object with a ‘_asyncio_future_blocking’
          attribute.

     Added in version 3.5.

 -- Function: asyncio.ensure_future (obj, *, loop=None)

     Return:

        * 'obj' argument as is, if 'obj' is a *note Future: bec, a *note
          Task: 1be, or a Future-like object (*note isfuture(): 3593. is
          used for the test.)

        * a *note Task: 1be. object wrapping 'obj', if 'obj' is a
          coroutine (*note iscoroutine(): 481. is used for the test); in
          this case the coroutine will be scheduled by
          ‘ensure_future()’.

        * a *note Task: 1be. object that would await on 'obj', if 'obj'
          is an awaitable (*note inspect.isawaitable(): e49. is used for
          the test.)

     If 'obj' is neither of the above a *note TypeError: 2c3. is raised.

          Important: See also the *note create_task(): 1bf. function
          which is the preferred way for creating new Tasks.

          Save a reference to the result of this function, to avoid a
          task disappearing mid-execution.

     Changed in version 3.5.1: The function accepts any *note awaitable:
     1ad. object.

     Deprecated since version 3.10: Deprecation warning is emitted if
     'obj' is not a Future-like object and 'loop' is not specified and
     there is no running event loop.

 -- Function: asyncio.wrap_future (future, *, loop=None)

     Wrap a *note concurrent.futures.Future: 11f6. object in a *note
     asyncio.Future: bec. object.

     Deprecated since version 3.10: Deprecation warning is emitted if
     'future' is not a Future-like object and 'loop' is not specified
     and there is no running event loop.


File: python.info,  Node: Future Object,  Prev: Future Functions,  Up: Futures

5.19.1.79 Future Object
.......................

 -- Class: asyncio.Future (*, loop=None)

     A Future represents an eventual result of an asynchronous
     operation.  Not thread-safe.

     Future is an *note awaitable: 1ad. object.  Coroutines can await on
     Future objects until they either have a result or an exception set,
     or until they are cancelled.  A Future can be awaited multiple
     times and the result is same.

     Typically Futures are used to enable low-level callback-based code
     (e.g.  in protocols implemented using asyncio *note transports:
     3496.) to interoperate with high-level async/await code.

     The rule of thumb is to never expose Future objects in user-facing
     APIs, and the recommended way to create a Future object is to call
     *note loop.create_future(): c9b.  This way alternative event loop
     implementations can inject their own optimized implementations of a
     Future object.

     Changed in version 3.7: Added support for the *note contextvars:
     24. module.

     Deprecated since version 3.10: Deprecation warning is emitted if
     'loop' is not specified and there is no running event loop.

      -- Method: result ()

          Return the result of the Future.

          If the Future is 'done' and has a result set by the *note
          set_result(): 34c3. method, the result value is returned.

          If the Future is 'done' and has an exception set by the *note
          set_exception(): c9f. method, this method raises the
          exception.

          If the Future has been 'cancelled', this method raises a *note
          CancelledError: 1b8. exception.

          If the Future’s result isn’t yet available, this method raises
          an *note InvalidStateError: 34c6. exception.

      -- Method: set_result (result)

          Mark the Future as 'done' and set its result.

          Raises an *note InvalidStateError: 34c6. error if the Future
          is already 'done'.

      -- Method: set_exception (exception)

          Mark the Future as 'done' and set an exception.

          Raises an *note InvalidStateError: 34c6. error if the Future
          is already 'done'.

      -- Method: done ()

          Return ‘True’ if the Future is 'done'.

          A Future is 'done' if it was 'cancelled' or if it has a result
          or an exception set with *note set_result(): 34c3. or *note
          set_exception(): c9f. calls.

      -- Method: cancelled ()

          Return ‘True’ if the Future was 'cancelled'.

          The method is usually used to check if a Future is not
          'cancelled' before setting a result or an exception for it:

               if not fut.cancelled():
                   fut.set_result(42)

      -- Method: add_done_callback (callback, *, context=None)

          Add a callback to be run when the Future is 'done'.

          The 'callback' is called with the Future object as its only
          argument.

          If the Future is already 'done' when this method is called,
          the callback is scheduled with *note loop.call_soon(): b1d.

          An optional keyword-only 'context' argument allows specifying
          a custom *note contextvars.Context: 15dd. for the 'callback'
          to run in.  The current context is used when no 'context' is
          provided.

          *note functools.partial(): 417. can be used to pass parameters
          to the callback, e.g.:

               # Call 'print("Future:", fut)' when "fut" is done.
               fut.add_done_callback(
                   functools.partial(print, "Future:"))

          Changed in version 3.7: The 'context' keyword-only parameter
          was added.  See PEP 567(1) for more details.

      -- Method: remove_done_callback (callback)

          Remove 'callback' from the callbacks list.

          Returns the number of callbacks removed, which is typically 1,
          unless a callback was added more than once.

      -- Method: cancel (msg=None)

          Cancel the Future and schedule callbacks.

          If the Future is already 'done' or 'cancelled', return
          ‘False’.  Otherwise, change the Future’s state to 'cancelled',
          schedule the callbacks, and return ‘True’.

          Changed in version 3.9: Added the 'msg' parameter.

      -- Method: exception ()

          Return the exception that was set on this Future.

          The exception (or ‘None’ if no exception was set) is returned
          only if the Future is 'done'.

          If the Future has been 'cancelled', this method raises a *note
          CancelledError: 1b8. exception.

          If the Future isn’t 'done' yet, this method raises an *note
          InvalidStateError: 34c6. exception.

      -- Method: get_loop ()

          Return the event loop the Future object is bound to.

          Added in version 3.7.

This example creates a Future object, creates and schedules an
asynchronous Task to set result for the Future, and waits until the
Future has a result:

     async def set_after(fut, delay, value):
         # Sleep for *delay* seconds.
         await asyncio.sleep(delay)

         # Set *value* as a result of *fut* Future.
         fut.set_result(value)

     async def main():
         # Get the current event loop.
         loop = asyncio.get_running_loop()

         # Create a new Future object.
         fut = loop.create_future()

         # Run "set_after()" coroutine in a parallel Task.
         # We are using the low-level "loop.create_task()" API here because
         # we already have a reference to the event loop at hand.
         # Otherwise we could have just used "asyncio.create_task()".
         loop.create_task(
             set_after(fut, 1, '... world'))

         print('hello ...')

         # Wait until *fut* has a result (1 second) and print it.
         print(await fut)

     asyncio.run(main())

     Important: The Future object was designed to mimic *note
     concurrent.futures.Future: 11f6.  Key differences include:

        - unlike asyncio Futures, *note concurrent.futures.Future: 11f6.
          instances cannot be awaited.

        - *note asyncio.Future.result(): 3596. and *note
          asyncio.Future.exception(): 3599. do not accept the 'timeout'
          argument.

        - *note asyncio.Future.result(): 3596. and *note
          asyncio.Future.exception(): 3599. raise an *note
          InvalidStateError: 34c6. exception when the Future is not
          'done'.

        - Callbacks registered with *note
          asyncio.Future.add_done_callback(): b21. are not called
          immediately.  They are scheduled with *note loop.call_soon():
          b1d. instead.

        - asyncio Future is not compatible with the *note
          concurrent.futures.wait(): 19a9. and *note
          concurrent.futures.as_completed(): 175b. functions.

        - *note asyncio.Future.cancel(): 194f. accepts an optional ‘msg’
          argument, but *note concurrent.futures.Future.cancel(): 33e7.
          does not.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0567/


File: python.info,  Node: Transports and Protocols,  Next: Policies,  Prev: Futures,  Up: asyncio — Asynchronous I/O

5.19.1.80 Transports and Protocols
..................................

Preface
.......

Transports and Protocols are used by the 'low-level' event loop APIs
such as *note loop.create_connection(): 606.  They use callback-based
programming style and enable high-performance implementations of network
or IPC protocols (e.g.  HTTP).

Essentially, transports and protocols should only be used in libraries
and frameworks and never in high-level asyncio applications.

This documentation page covers both *note Transports: 359e. and *note
Protocols: 359f.

Introduction
............

At the highest level, the transport is concerned with 'how' bytes are
transmitted, while the protocol determines 'which' bytes to transmit
(and to some extent when).

A different way of saying the same thing: a transport is an abstraction
for a socket (or similar I/O endpoint) while a protocol is an
abstraction for an application, from the transport’s point of view.

Yet another view is the transport and protocol interfaces together
define an abstract interface for using network I/O and interprocess I/O.

There is always a 1:1 relationship between transport and protocol
objects: the protocol calls transport methods to send data, while the
transport calls protocol methods to pass it data that has been received.

Most of connection oriented event loop methods (such as *note
loop.create_connection(): 606.) usually accept a 'protocol_factory'
argument used to create a 'Protocol' object for an accepted connection,
represented by a 'Transport' object.  Such methods usually return a
tuple of ‘(transport, protocol)’.

Contents
........

This documentation page contains the following sections:

   * The *note Transports: 359e. section documents asyncio *note
     BaseTransport: 35a0, *note ReadTransport: 3575, *note
     WriteTransport: 3576, *note Transport: 35a1, *note
     DatagramTransport: 18ca, and *note SubprocessTransport: 3583.
     classes.

   * The *note Protocols: 359f. section documents asyncio *note
     BaseProtocol: 35a2, *note Protocol: 35a3, *note BufferedProtocol:
     ab2, *note DatagramProtocol: 6d2, and *note SubprocessProtocol:
     3582. classes.

   * The *note Examples: 35a4. section showcases how to work with
     transports, protocols, and low-level event loop APIs.

* Menu:

* Transports::
* Protocols::
* Examples: Examples<19>.


File: python.info,  Node: Transports,  Next: Protocols,  Up: Transports and Protocols

5.19.1.81 Transports
....................

'Source code:' Lib/asyncio/transports.py(1)

__________________________________________________________________

Transports are classes provided by *note asyncio: a. in order to
abstract various kinds of communication channels.

Transport objects are always instantiated by an *note asyncio event
loop: da4.

asyncio implements transports for TCP, UDP, SSL, and subprocess pipes.
The methods available on a transport depend on the transport’s kind.

The transport classes are *note not thread safe: 34be.

* Menu:

* Transports Hierarchy::
* Base Transport::
* Read-only Transports::
* Write-only Transports::
* Datagram Transports::
* Subprocess Transports::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/transports.py


File: python.info,  Node: Transports Hierarchy,  Next: Base Transport,  Up: Transports

5.19.1.82 Transports Hierarchy
..............................

 -- Class: asyncio.BaseTransport

     Base class for all transports.  Contains methods that all asyncio
     transports share.

 -- Class: asyncio.WriteTransport (BaseTransport)

     A base transport for write-only connections.

     Instances of the 'WriteTransport' class are returned from the *note
     loop.connect_write_pipe(): 351d. event loop method and are also
     used by subprocess-related methods like *note
     loop.subprocess_exec(): 3519.

 -- Class: asyncio.ReadTransport (BaseTransport)

     A base transport for read-only connections.

     Instances of the 'ReadTransport' class are returned from the *note
     loop.connect_read_pipe(): 351c. event loop method and are also used
     by subprocess-related methods like *note loop.subprocess_exec():
     3519.

 -- Class: asyncio.Transport (WriteTransport, ReadTransport)

     Interface representing a bidirectional transport, such as a TCP
     connection.

     The user does not instantiate a transport directly; they call a
     utility function, passing it a protocol factory and other
     information necessary to create the transport and protocol.

     Instances of the 'Transport' class are returned from or used by
     event loop methods like *note loop.create_connection(): 606, *note
     loop.create_unix_connection(): 34d5, *note loop.create_server():
     b2c, *note loop.sendfile(): 356b, etc.

 -- Class: asyncio.DatagramTransport (BaseTransport)

     A transport for datagram (UDP) connections.

     Instances of the 'DatagramTransport' class are returned from the
     *note loop.create_datagram_endpoint(): 736. event loop method.

 -- Class: asyncio.SubprocessTransport (BaseTransport)

     An abstraction to represent a connection between a parent and its
     child OS process.

     Instances of the 'SubprocessTransport' class are returned from
     event loop methods *note loop.subprocess_shell(): 351a. and *note
     loop.subprocess_exec(): 3519.


File: python.info,  Node: Base Transport,  Next: Read-only Transports,  Prev: Transports Hierarchy,  Up: Transports

5.19.1.83 Base Transport
........................

 -- Method: BaseTransport.close ()

     Close the transport.

     If the transport has a buffer for outgoing data, buffered data will
     be flushed asynchronously.  No more data will be received.  After
     all buffered data is flushed, the protocol’s *note
     protocol.connection_lost(): 35a7. method will be called with *note
     None: 678. as its argument.  The transport should not be used once
     it is closed.

 -- Method: BaseTransport.is_closing ()

     Return ‘True’ if the transport is closing or is closed.

 -- Method: BaseTransport.get_extra_info (name, default=None)

     Return information about the transport or underlying resources it
     uses.

     'name' is a string representing the piece of transport-specific
     information to get.

     'default' is the value to return if the information is not
     available, or if the transport does not support querying it with
     the given third-party event loop implementation or on the current
     platform.

     For example, the following code attempts to get the underlying
     socket object of the transport:

          sock = transport.get_extra_info('socket')
          if sock is not None:
              print(sock.getsockopt(...))

     Categories of information that can be queried on some transports:

        * socket:

             - ‘'peername'’: the remote address to which the socket is
               connected, result of *note socket.socket.getpeername():
               35a8. (‘None’ on error)

             - ‘'socket'’: *note socket.socket: dcf. instance

             - ‘'sockname'’: the socket’s own address, result of *note
               socket.socket.getsockname(): 35a9.

        * SSL socket:

             - ‘'compression'’: the compression algorithm being used as
               a string, or ‘None’ if the connection isn’t compressed;
               result of *note ssl.SSLSocket.compression(): 1189.

             - ‘'cipher'’: a three-value tuple containing the name of
               the cipher being used, the version of the SSL protocol
               that defines its use, and the number of secret bits being
               used; result of *note ssl.SSLSocket.cipher(): 35aa.

             - ‘'peercert'’: peer certificate; result of *note
               ssl.SSLSocket.getpeercert(): ff1.

             - ‘'sslcontext'’: *note ssl.SSLContext: 294. instance

             - ‘'ssl_object'’: *note ssl.SSLObject: b9f. or *note
               ssl.SSLSocket: 8f3. instance

        * pipe:

             - ‘'pipe'’: pipe object

        * subprocess:

             - ‘'subprocess'’: *note subprocess.Popen: 199. instance

 -- Method: BaseTransport.set_protocol (protocol)

     Set a new protocol.

     Switching protocol should only be done when both protocols are
     documented to support the switch.

 -- Method: BaseTransport.get_protocol ()

     Return the current protocol.


File: python.info,  Node: Read-only Transports,  Next: Write-only Transports,  Prev: Base Transport,  Up: Transports

5.19.1.84 Read-only Transports
..............................

 -- Method: ReadTransport.is_reading ()

     Return ‘True’ if the transport is receiving new data.

     Added in version 3.7.

 -- Method: ReadTransport.pause_reading ()

     Pause the receiving end of the transport.  No data will be passed
     to the protocol’s *note protocol.data_received(): 18a5. method
     until *note resume_reading(): b35. is called.

     Changed in version 3.7: The method is idempotent, i.e.  it can be
     called when the transport is already paused or closed.

 -- Method: ReadTransport.resume_reading ()

     Resume the receiving end.  The protocol’s *note
     protocol.data_received(): 18a5. method will be called once again if
     some data is available for reading.

     Changed in version 3.7: The method is idempotent, i.e.  it can be
     called when the transport is already reading.


File: python.info,  Node: Write-only Transports,  Next: Datagram Transports,  Prev: Read-only Transports,  Up: Transports

5.19.1.85 Write-only Transports
...............................

 -- Method: WriteTransport.abort ()

     Close the transport immediately, without waiting for pending
     operations to complete.  Buffered data will be lost.  No more data
     will be received.  The protocol’s *note protocol.connection_lost():
     35a7. method will eventually be called with *note None: 678. as its
     argument.

 -- Method: WriteTransport.can_write_eof ()

     Return *note True: c2d. if the transport supports *note
     write_eof(): 35b0, *note False: b4f. if not.

 -- Method: WriteTransport.get_write_buffer_size ()

     Return the current size of the output buffer used by the transport.

 -- Method: WriteTransport.get_write_buffer_limits ()

     Get the 'high' and 'low' watermarks for write flow control.  Return
     a tuple ‘(low, high)’ where 'low' and 'high' are positive number of
     bytes.

     Use *note set_write_buffer_limits(): 35b2. to set the limits.

     Added in version 3.4.2.

 -- Method: WriteTransport.set_write_buffer_limits (high=None, low=None)

     Set the 'high' and 'low' watermarks for write flow control.

     These two values (measured in number of bytes) control when the
     protocol’s *note protocol.pause_writing(): 35b3. and *note
     protocol.resume_writing(): 35b4. methods are called.  If specified,
     the low watermark must be less than or equal to the high watermark.
     Neither 'high' nor 'low' can be negative.

     *note pause_writing(): 35b3. is called when the buffer size becomes
     greater than or equal to the 'high' value.  If writing has been
     paused, *note resume_writing(): 35b4. is called when the buffer
     size becomes less than or equal to the 'low' value.

     The defaults are implementation-specific.  If only the high
     watermark is given, the low watermark defaults to an
     implementation-specific value less than or equal to the high
     watermark.  Setting 'high' to zero forces 'low' to zero as well,
     and causes *note pause_writing(): 35b3. to be called whenever the
     buffer becomes non-empty.  Setting 'low' to zero causes *note
     resume_writing(): 35b4. to be called only once the buffer is empty.
     Use of zero for either limit is generally sub-optimal as it reduces
     opportunities for doing I/O and computation concurrently.

     Use *note get_write_buffer_limits(): df3. to get the limits.

 -- Method: WriteTransport.write (data)

     Write some 'data' bytes to the transport.

     This method does not block; it buffers the data and arranges for it
     to be sent out asynchronously.

 -- Method: WriteTransport.writelines (list_of_data)

     Write a list (or any iterable) of data bytes to the transport.
     This is functionally equivalent to calling *note write(): 1601. on
     each element yielded by the iterable, but may be implemented more
     efficiently.

 -- Method: WriteTransport.write_eof ()

     Close the write end of the transport after flushing all buffered
     data.  Data may still be received.

     This method can raise *note NotImplementedError: 228. if the
     transport (e.g.  SSL) doesn’t support half-closed connections.


File: python.info,  Node: Datagram Transports,  Next: Subprocess Transports,  Prev: Write-only Transports,  Up: Transports

5.19.1.86 Datagram Transports
.............................

 -- Method: DatagramTransport.sendto (data, addr=None)

     Send the 'data' bytes to the remote peer given by 'addr' (a
     transport-dependent target address).  If 'addr' is *note None: 678,
     the data is sent to the target address given on transport creation.

     This method does not block; it buffers the data and arranges for it
     to be sent out asynchronously.

     Changed in version 3.13: This method can be called with an empty
     bytes object to send a zero-length datagram.  The buffer size
     calculation used for flow control is also updated to account for
     the datagram header.

 -- Method: DatagramTransport.abort ()

     Close the transport immediately, without waiting for pending
     operations to complete.  Buffered data will be lost.  No more data
     will be received.  The protocol’s *note protocol.connection_lost():
     35a7. method will eventually be called with *note None: 678. as its
     argument.


File: python.info,  Node: Subprocess Transports,  Prev: Datagram Transports,  Up: Transports

5.19.1.87 Subprocess Transports
...............................

 -- Method: SubprocessTransport.get_pid ()

     Return the subprocess process id as an integer.

 -- Method: SubprocessTransport.get_pipe_transport (fd)

     Return the transport for the communication pipe corresponding to
     the integer file descriptor 'fd':

        * ‘0’: writable streaming transport of the standard input
          ('stdin'), or *note None: 678. if the subprocess was not
          created with ‘stdin=PIPE’

        * ‘1’: readable streaming transport of the standard output
          ('stdout'), or *note None: 678. if the subprocess was not
          created with ‘stdout=PIPE’

        * ‘2’: readable streaming transport of the standard error
          ('stderr'), or *note None: 678. if the subprocess was not
          created with ‘stderr=PIPE’

        * other 'fd': *note None: 678.

 -- Method: SubprocessTransport.get_returncode ()

     Return the subprocess return code as an integer or *note None: 678.
     if it hasn’t returned, which is similar to the *note
     subprocess.Popen.returncode: aa1. attribute.

 -- Method: SubprocessTransport.kill ()

     Kill the subprocess.

     On POSIX systems, the function sends SIGKILL to the subprocess.  On
     Windows, this method is an alias for *note terminate(): 35bc.

     See also *note subprocess.Popen.kill(): 142b.

 -- Method: SubprocessTransport.send_signal (signal)

     Send the 'signal' number to the subprocess, as in *note
     subprocess.Popen.send_signal(): 142c.

 -- Method: SubprocessTransport.terminate ()

     Stop the subprocess.

     On POSIX systems, this method sends *note SIGTERM: 142d. to the
     subprocess.  On Windows, the Windows API function
     ‘TerminateProcess()’ is called to stop the subprocess.

     See also *note subprocess.Popen.terminate(): 142a.

 -- Method: SubprocessTransport.close ()

     Kill the subprocess by calling the *note kill(): 35bb. method.

     If the subprocess hasn’t returned yet, and close transports of
     'stdin', 'stdout', and 'stderr' pipes.


File: python.info,  Node: Protocols,  Next: Examples<19>,  Prev: Transports,  Up: Transports and Protocols

5.19.1.88 Protocols
...................

'Source code:' Lib/asyncio/protocols.py(1)

__________________________________________________________________

asyncio provides a set of abstract base classes that should be used to
implement network protocols.  Those classes are meant to be used
together with *note transports: 3562.

Subclasses of abstract base protocol classes may implement some or all
methods.  All these methods are callbacks: they are called by transports
on certain events, for example when some data is received.  A base
protocol method should be called by the corresponding transport.

* Menu:

* Base Protocols::
* Base Protocol::
* Streaming Protocols::
* Buffered Streaming Protocols::
* Datagram Protocols::
* Subprocess Protocols::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/protocols.py


File: python.info,  Node: Base Protocols,  Next: Base Protocol,  Up: Protocols

5.19.1.89 Base Protocols
........................

 -- Class: asyncio.BaseProtocol

     Base protocol with methods that all protocols share.

 -- Class: asyncio.Protocol (BaseProtocol)

     The base class for implementing streaming protocols (TCP, Unix
     sockets, etc).

 -- Class: asyncio.BufferedProtocol (BaseProtocol)

     A base class for implementing streaming protocols with manual
     control of the receive buffer.

 -- Class: asyncio.DatagramProtocol (BaseProtocol)

     The base class for implementing datagram (UDP) protocols.

 -- Class: asyncio.SubprocessProtocol (BaseProtocol)

     The base class for implementing protocols communicating with child
     processes (unidirectional pipes).


File: python.info,  Node: Base Protocol,  Next: Streaming Protocols,  Prev: Base Protocols,  Up: Protocols

5.19.1.90 Base Protocol
.......................

All asyncio protocols can implement Base Protocol callbacks.

Connection Callbacks
....................

Connection callbacks are called on all protocols, exactly once per a
successful connection.  All other protocol callbacks can only be called
between those two methods.

 -- Method: BaseProtocol.connection_made (transport)

     Called when a connection is made.

     The 'transport' argument is the transport representing the
     connection.  The protocol is responsible for storing the reference
     to its transport.

 -- Method: BaseProtocol.connection_lost (exc)

     Called when the connection is lost or closed.

     The argument is either an exception object or *note None: 678.  The
     latter means a regular EOF is received, or the connection was
     aborted or closed by this side of the connection.

Flow Control Callbacks
......................

Flow control callbacks can be called by transports to pause or resume
writing performed by the protocol.

See the documentation of the *note set_write_buffer_limits(): 35b2.
method for more details.

 -- Method: BaseProtocol.pause_writing ()

     Called when the transport’s buffer goes over the high watermark.

 -- Method: BaseProtocol.resume_writing ()

     Called when the transport’s buffer drains below the low watermark.

If the buffer size equals the high watermark, *note pause_writing():
35b3. is not called: the buffer size must go strictly over.

Conversely, *note resume_writing(): 35b4. is called when the buffer size
is equal or lower than the low watermark.  These end conditions are
important to ensure that things go as expected when either mark is zero.


File: python.info,  Node: Streaming Protocols,  Next: Buffered Streaming Protocols,  Prev: Base Protocol,  Up: Protocols

5.19.1.91 Streaming Protocols
.............................

Event methods, such as *note loop.create_server(): b2c, *note
loop.create_unix_server(): 1ae, *note loop.create_connection(): 606,
*note loop.create_unix_connection(): 34d5, *note
loop.connect_accepted_socket(): 7e2, *note loop.connect_read_pipe():
351c, and *note loop.connect_write_pipe(): 351d. accept factories that
return streaming protocols.

 -- Method: Protocol.data_received (data)

     Called when some data is received.  'data' is a non-empty bytes
     object containing the incoming data.

     Whether the data is buffered, chunked or reassembled depends on the
     transport.  In general, you shouldn’t rely on specific semantics
     and instead make your parsing generic and flexible.  However, data
     is always received in the correct order.

     The method can be called an arbitrary number of times while a
     connection is open.

     However, *note protocol.eof_received(): 35c2. is called at most
     once.  Once ‘eof_received()’ is called, ‘data_received()’ is not
     called anymore.

 -- Method: Protocol.eof_received ()

     Called when the other end signals it won’t send any more data (for
     example by calling *note transport.write_eof(): 35b0, if the other
     end also uses asyncio).

     This method may return a false value (including ‘None’), in which
     case the transport will close itself.  Conversely, if this method
     returns a true value, the protocol used determines whether to close
     the transport.  Since the default implementation returns ‘None’, it
     implicitly closes the connection.

     Some transports, including SSL, don’t support half-closed
     connections, in which case returning true from this method will
     result in the connection being closed.

State machine:

     start -> connection_made
         [-> data_received]*
         [-> eof_received]?
     -> connection_lost -> end


File: python.info,  Node: Buffered Streaming Protocols,  Next: Datagram Protocols,  Prev: Streaming Protocols,  Up: Protocols

5.19.1.92 Buffered Streaming Protocols
......................................

Added in version 3.7.

Buffered Protocols can be used with any event loop method that supports
*note Streaming Protocols: 35c1.

‘BufferedProtocol’ implementations allow explicit manual allocation and
control of the receive buffer.  Event loops can then use the buffer
provided by the protocol to avoid unnecessary data copies.  This can
result in noticeable performance improvement for protocols that receive
big amounts of data.  Sophisticated protocol implementations can
significantly reduce the number of buffer allocations.

The following callbacks are called on *note BufferedProtocol: ab2.
instances:

 -- Method: BufferedProtocol.get_buffer (sizehint)

     Called to allocate a new receive buffer.

     'sizehint' is the recommended minimum size for the returned buffer.
     It is acceptable to return smaller or larger buffers than what
     'sizehint' suggests.  When set to -1, the buffer size can be
     arbitrary.  It is an error to return a buffer with a zero size.

     ‘get_buffer()’ must return an object implementing the *note buffer
     protocol: 2e8.

 -- Method: BufferedProtocol.buffer_updated (nbytes)

     Called when the buffer was updated with the received data.

     'nbytes' is the total number of bytes that were written to the
     buffer.

 -- Method: BufferedProtocol.eof_received ()

     See the documentation of the *note protocol.eof_received(): 35c2.
     method.

*note get_buffer(): 35c4. can be called an arbitrary number of times
during a connection.  However, *note protocol.eof_received(): 35c2. is
called at most once and, if called, ‘get_buffer()’ and *note
buffer_updated(): 35c5. won’t be called after it.

State machine:

     start -> connection_made
         [-> get_buffer
             [-> buffer_updated]?
         ]*
         [-> eof_received]?
     -> connection_lost -> end


File: python.info,  Node: Datagram Protocols,  Next: Subprocess Protocols,  Prev: Buffered Streaming Protocols,  Up: Protocols

5.19.1.93 Datagram Protocols
............................

Datagram Protocol instances should be constructed by protocol factories
passed to the *note loop.create_datagram_endpoint(): 736. method.

 -- Method: DatagramProtocol.datagram_received (data, addr)

     Called when a datagram is received.  'data' is a bytes object
     containing the incoming data.  'addr' is the address of the peer
     sending the data; the exact format depends on the transport.

 -- Method: DatagramProtocol.error_received (exc)

     Called when a previous send or receive operation raises an *note
     OSError: 41a.  'exc' is the ‘OSError’ instance.

     This method is called in rare conditions, when the transport (e.g.
     UDP) detects that a datagram could not be delivered to its
     recipient.  In many conditions though, undeliverable datagrams will
     be silently dropped.

     Note: On BSD systems (macOS, FreeBSD, etc.)  flow control is not
     supported for datagram protocols, because there is no reliable way
     to detect send failures caused by writing too many packets.

     The socket always appears ‘ready’ and excess packets are dropped.
     An *note OSError: 41a. with ‘errno’ set to *note errno.ENOBUFS:
     1917. may or may not be raised; if it is raised, it will be
     reported to *note DatagramProtocol.error_received(): 35c9. but
     otherwise ignored.


File: python.info,  Node: Subprocess Protocols,  Prev: Datagram Protocols,  Up: Protocols

5.19.1.94 Subprocess Protocols
..............................

Subprocess Protocol instances should be constructed by protocol
factories passed to the *note loop.subprocess_exec(): 3519. and *note
loop.subprocess_shell(): 351a. methods.

 -- Method: SubprocessProtocol.pipe_data_received (fd, data)

     Called when the child process writes data into its stdout or stderr
     pipe.

     'fd' is the integer file descriptor of the pipe.

     'data' is a non-empty bytes object containing the received data.

 -- Method: SubprocessProtocol.pipe_connection_lost (fd, exc)

     Called when one of the pipes communicating with the child process
     is closed.

     'fd' is the integer file descriptor that was closed.

 -- Method: SubprocessProtocol.process_exited ()

     Called when the child process has exited.

     It can be called before *note pipe_data_received(): 18f4. and *note
     pipe_connection_lost(): 35cb. methods.


File: python.info,  Node: Examples<19>,  Prev: Protocols,  Up: Transports and Protocols

5.19.1.95 Examples
..................

* Menu:

* TCP Echo Server::
* TCP Echo Client::
* UDP Echo Server::
* UDP Echo Client::
* Connecting Existing Sockets::
* loop.subprocess_exec() and SubprocessProtocol: loop subprocess_exec and SubprocessProtocol.


File: python.info,  Node: TCP Echo Server,  Next: TCP Echo Client,  Up: Examples<19>

5.19.1.96 TCP Echo Server
.........................

Create a TCP echo server using the *note loop.create_server(): b2c.
method, send back received data, and close the connection:

     import asyncio


     class EchoServerProtocol(asyncio.Protocol):
         def connection_made(self, transport):
             peername = transport.get_extra_info('peername')
             print('Connection from {}'.format(peername))
             self.transport = transport

         def data_received(self, data):
             message = data.decode()
             print('Data received: {!r}'.format(message))

             print('Send: {!r}'.format(message))
             self.transport.write(data)

             print('Close the client socket')
             self.transport.close()


     async def main():
         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()

         server = await loop.create_server(
             EchoServerProtocol,
             '127.0.0.1', 8888)

         async with server:
             await server.serve_forever()


     asyncio.run(main())

See also
........

The *note TCP echo server using streams: 34e8. example uses the
high-level *note asyncio.start_server(): b32. function.


File: python.info,  Node: TCP Echo Client,  Next: UDP Echo Server,  Prev: TCP Echo Server,  Up: Examples<19>

5.19.1.97 TCP Echo Client
.........................

A TCP echo client using the *note loop.create_connection(): 606. method,
sends data, and waits until the connection is closed:

     import asyncio


     class EchoClientProtocol(asyncio.Protocol):
         def __init__(self, message, on_con_lost):
             self.message = message
             self.on_con_lost = on_con_lost

         def connection_made(self, transport):
             transport.write(self.message.encode())
             print('Data sent: {!r}'.format(self.message))

         def data_received(self, data):
             print('Data received: {!r}'.format(data.decode()))

         def connection_lost(self, exc):
             print('The server closed the connection')
             self.on_con_lost.set_result(True)


     async def main():
         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()

         on_con_lost = loop.create_future()
         message = 'Hello World!'

         transport, protocol = await loop.create_connection(
             lambda: EchoClientProtocol(message, on_con_lost),
             '127.0.0.1', 8888)

         # Wait until the protocol signals that the connection
         # is lost and close the transport.
         try:
             await on_con_lost
         finally:
             transport.close()


     asyncio.run(main())

See also
........

The *note TCP echo client using streams: 34e5. example uses the
high-level *note asyncio.open_connection(): b31. function.


File: python.info,  Node: UDP Echo Server,  Next: UDP Echo Client,  Prev: TCP Echo Client,  Up: Examples<19>

5.19.1.98 UDP Echo Server
.........................

A UDP echo server, using the *note loop.create_datagram_endpoint(): 736.
method, sends back received data:

     import asyncio


     class EchoServerProtocol:
         def connection_made(self, transport):
             self.transport = transport

         def datagram_received(self, data, addr):
             message = data.decode()
             print('Received %r from %s' % (message, addr))
             print('Send %r to %s' % (message, addr))
             self.transport.sendto(data, addr)


     async def main():
         print("Starting UDP server")

         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()

         # One protocol instance will be created to serve all
         # client requests.
         transport, protocol = await loop.create_datagram_endpoint(
             EchoServerProtocol,
             local_addr=('127.0.0.1', 9999))

         try:
             await asyncio.sleep(3600)  # Serve for 1 hour.
         finally:
             transport.close()


     asyncio.run(main())


File: python.info,  Node: UDP Echo Client,  Next: Connecting Existing Sockets,  Prev: UDP Echo Server,  Up: Examples<19>

5.19.1.99 UDP Echo Client
.........................

A UDP echo client, using the *note loop.create_datagram_endpoint(): 736.
method, sends data and closes the transport when it receives the answer:

     import asyncio


     class EchoClientProtocol:
         def __init__(self, message, on_con_lost):
             self.message = message
             self.on_con_lost = on_con_lost
             self.transport = None

         def connection_made(self, transport):
             self.transport = transport
             print('Send:', self.message)
             self.transport.sendto(self.message.encode())

         def datagram_received(self, data, addr):
             print("Received:", data.decode())

             print("Close the socket")
             self.transport.close()

         def error_received(self, exc):
             print('Error received:', exc)

         def connection_lost(self, exc):
             print("Connection closed")
             self.on_con_lost.set_result(True)


     async def main():
         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()

         on_con_lost = loop.create_future()
         message = "Hello World!"

         transport, protocol = await loop.create_datagram_endpoint(
             lambda: EchoClientProtocol(message, on_con_lost),
             remote_addr=('127.0.0.1', 9999))

         try:
             await on_con_lost
         finally:
             transport.close()


     asyncio.run(main())


File: python.info,  Node: Connecting Existing Sockets,  Next: loop subprocess_exec and SubprocessProtocol,  Prev: UDP Echo Client,  Up: Examples<19>

5.19.1.100 Connecting Existing Sockets
......................................

Wait until a socket receives data using the *note
loop.create_connection(): 606. method with a protocol:

     import asyncio
     import socket


     class MyProtocol(asyncio.Protocol):

         def __init__(self, on_con_lost):
             self.transport = None
             self.on_con_lost = on_con_lost

         def connection_made(self, transport):
             self.transport = transport

         def data_received(self, data):
             print("Received:", data.decode())

             # We are done: close the transport;
             # connection_lost() will be called automatically.
             self.transport.close()

         def connection_lost(self, exc):
             # The socket has been closed
             self.on_con_lost.set_result(True)


     async def main():
         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()
         on_con_lost = loop.create_future()

         # Create a pair of connected sockets
         rsock, wsock = socket.socketpair()

         # Register the socket to wait for data.
         transport, protocol = await loop.create_connection(
             lambda: MyProtocol(on_con_lost), sock=rsock)

         # Simulate the reception of data from the network.
         loop.call_soon(wsock.send, 'abc'.encode())

         try:
             await protocol.on_con_lost
         finally:
             transport.close()
             wsock.close()

     asyncio.run(main())

See also
........

The *note watch a file descriptor for read events: 34ef. example uses
the low-level *note loop.add_reader(): 34f0. method to register an FD.

The *note register an open socket to wait for data using streams: 34ec.
example uses high-level streams created by the *note open_connection():
b31. function in a coroutine.


File: python.info,  Node: loop subprocess_exec and SubprocessProtocol,  Prev: Connecting Existing Sockets,  Up: Examples<19>

5.19.1.101 loop.subprocess_exec() and SubprocessProtocol
........................................................

An example of a subprocess protocol used to get the output of a
subprocess and to wait for the subprocess exit.

The subprocess is created by the *note loop.subprocess_exec(): 3519.
method:

     import asyncio
     import sys

     class DateProtocol(asyncio.SubprocessProtocol):
         def __init__(self, exit_future):
             self.exit_future = exit_future
             self.output = bytearray()
             self.pipe_closed = False
             self.exited = False

         def pipe_connection_lost(self, fd, exc):
             self.pipe_closed = True
             self.check_for_exit()

         def pipe_data_received(self, fd, data):
             self.output.extend(data)

         def process_exited(self):
             self.exited = True
             # process_exited() method can be called before
             # pipe_connection_lost() method: wait until both methods are
             # called.
             self.check_for_exit()

         def check_for_exit(self):
             if self.pipe_closed and self.exited:
                 self.exit_future.set_result(True)

     async def get_date():
         # Get a reference to the event loop as we plan to use
         # low-level APIs.
         loop = asyncio.get_running_loop()

         code = 'import datetime as dt; print(dt.datetime.now())'
         exit_future = asyncio.Future(loop=loop)

         # Create the subprocess controlled by DateProtocol;
         # redirect the standard output into a pipe.
         transport, protocol = await loop.subprocess_exec(
             lambda: DateProtocol(exit_future),
             sys.executable, '-c', code,
             stdin=None, stderr=None)

         # Wait for the subprocess exit using the process_exited()
         # method of the protocol.
         await exit_future

         # Close the stdout pipe.
         transport.close()

         # Read the output which was collected by the
         # pipe_data_received() method of the protocol.
         data = bytes(protocol.output)
         return data.decode('ascii').rstrip()

     date = asyncio.run(get_date())
     print(f"Current date: {date}")

See also the *note same example: 352e. written using high-level APIs.


File: python.info,  Node: Policies,  Next: Platform Support,  Prev: Transports and Protocols,  Up: asyncio — Asynchronous I/O

5.19.1.102 Policies
...................

An event loop policy is a global object used to get and set the current
*note event loop: da4, as well as create new event loops.  The default
policy can be *note replaced: 35d5. with *note built-in alternatives:
35d6. to use different event loop implementations, or substituted by a
*note custom policy: 35d7. that can override these behaviors.

The *note policy object: 35d8. gets and sets a separate event loop per
'context'.  This is per-thread by default, though custom policies could
define 'context' differently.

Custom event loop policies can control the behavior of *note
get_event_loop(): 2c2, *note set_event_loop(): 18fa, and *note
new_event_loop(): 349c.

Policy objects should implement the APIs defined in the *note
AbstractEventLoopPolicy: 35d9. abstract base class.

* Menu:

* Getting and Setting the Policy::
* Policy Objects::
* Process Watchers::
* Custom Policies::


File: python.info,  Node: Getting and Setting the Policy,  Next: Policy Objects,  Up: Policies

5.19.1.103 Getting and Setting the Policy
.........................................

The following functions can be used to get and set the policy for the
current process:

 -- Function: asyncio.get_event_loop_policy ()

     Return the current process-wide policy.

 -- Function: asyncio.set_event_loop_policy (policy)

     Set the current process-wide policy to 'policy'.

     If 'policy' is set to ‘None’, the default policy is restored.


File: python.info,  Node: Policy Objects,  Next: Process Watchers,  Prev: Getting and Setting the Policy,  Up: Policies

5.19.1.104 Policy Objects
.........................

The abstract event loop policy base class is defined as follows:

 -- Class: asyncio.AbstractEventLoopPolicy

     An abstract base class for asyncio policies.

      -- Method: get_event_loop ()

          Get the event loop for the current context.

          Return an event loop object implementing the *note
          AbstractEventLoop: 969. interface.

          This method should never return ‘None’.

          Changed in version 3.6.

      -- Method: set_event_loop (loop)

          Set the event loop for the current context to 'loop'.

      -- Method: new_event_loop ()

          Create and return a new event loop object.

          This method should never return ‘None’.

      -- Method: get_child_watcher ()

          Get a child process watcher object.

          Return a watcher object implementing the *note
          AbstractChildWatcher: 2bc. interface.

          This function is Unix specific.

          Deprecated since version 3.12.

      -- Method: set_child_watcher (watcher)

          Set the current child process watcher to 'watcher'.

          This function is Unix specific.

          Deprecated since version 3.12.

asyncio ships with the following built-in policies:

 -- Class: asyncio.DefaultEventLoopPolicy

     The default asyncio policy.  Uses *note SelectorEventLoop: 60b. on
     Unix and *note ProactorEventLoop: 60c. on Windows.

     There is no need to install the default policy manually.  asyncio
     is configured to use the default policy automatically.

     Changed in version 3.8: On Windows, *note ProactorEventLoop: 60c.
     is now used by default.

     Deprecated since version 3.12: The *note get_event_loop(): 2c2.
     method of the default asyncio policy now emits a *note
     DeprecationWarning: 1a5. if there is no current event loop set and
     it decides to create one.  In some future Python release this will
     become an error.

 -- Class: asyncio.WindowsSelectorEventLoopPolicy

     An alternative event loop policy that uses the *note
     SelectorEventLoop: 60b. event loop implementation.

     *note Availability: 1ef7.: Windows.

 -- Class: asyncio.WindowsProactorEventLoopPolicy

     An alternative event loop policy that uses the *note
     ProactorEventLoop: 60c. event loop implementation.

     *note Availability: 1ef7.: Windows.


File: python.info,  Node: Process Watchers,  Next: Custom Policies,  Prev: Policy Objects,  Up: Policies

5.19.1.105 Process Watchers
...........................

A process watcher allows customization of how an event loop monitors
child processes on Unix.  Specifically, the event loop needs to know
when a child process has exited.

In asyncio, child processes are created with *note
create_subprocess_exec(): a86. and *note loop.subprocess_exec(): 3519.
functions.

asyncio defines the *note AbstractChildWatcher: 2bc. abstract base
class, which child watchers should implement, and has four different
implementations: *note ThreadedChildWatcher: 47e. (configured to be used
by default), *note MultiLoopChildWatcher: 2ba, *note SafeChildWatcher:
2bd, and *note FastChildWatcher: 2bb.

See also the *note Subprocess and Threads: 3527. section.

The following two functions can be used to customize the child process
watcher implementation used by the asyncio event loop:

 -- Function: asyncio.get_child_watcher ()

     Return the current child watcher for the current policy.

     Deprecated since version 3.12.

 -- Function: asyncio.set_child_watcher (watcher)

     Set the current child watcher to 'watcher' for the current policy.
     'watcher' must implement methods defined in the *note
     AbstractChildWatcher: 2bc. base class.

     Deprecated since version 3.12.

     Note: Third-party event loops implementations might not support
     custom child watchers.  For such event loops, using *note
     set_child_watcher(): 2be. might be prohibited or have no effect.

 -- Class: asyncio.AbstractChildWatcher

      -- Method: add_child_handler (pid, callback, *args)

          Register a new child handler.

          Arrange for ‘callback(pid, returncode, *args)’ to be called
          when a process with PID equal to 'pid' terminates.  Specifying
          another callback for the same process replaces the previous
          handler.

          The 'callback' callable must be thread-safe.

      -- Method: remove_child_handler (pid)

          Removes the handler for process with PID equal to 'pid'.

          The function returns ‘True’ if the handler was successfully
          removed, ‘False’ if there was nothing to remove.

      -- Method: attach_loop (loop)

          Attach the watcher to an event loop.

          If the watcher was previously attached to an event loop, then
          it is first detached before attaching to the new loop.

          Note: loop may be ‘None’.

      -- Method: is_active ()

          Return ‘True’ if the watcher is ready to use.

          Spawning a subprocess with 'inactive' current child watcher
          raises *note RuntimeError: 195.

          Added in version 3.8.

      -- Method: close ()

          Close the watcher.

          This method has to be called to ensure that underlying
          resources are cleaned-up.

     Deprecated since version 3.12.

 -- Class: asyncio.ThreadedChildWatcher

     This implementation starts a new waiting thread for every
     subprocess spawn.

     It works reliably even when the asyncio event loop is run in a
     non-main OS thread.

     There is no noticeable overhead when handling a big number of
     children ('O'(1) each time a child terminates), but starting a
     thread per process requires extra memory.

     This watcher is used by default.

     Added in version 3.8.

 -- Class: asyncio.MultiLoopChildWatcher

     This implementation registers a ‘SIGCHLD’ signal handler on
     instantiation.  That can break third-party code that installs a
     custom handler for ‘SIGCHLD’ signal.

     The watcher avoids disrupting other code spawning processes by
     polling every process explicitly on a ‘SIGCHLD’ signal.

     There is no limitation for running subprocesses from different
     threads once the watcher is installed.

     The solution is safe but it has a significant overhead when
     handling a big number of processes ('O'('n') each time a ‘SIGCHLD’
     is received).

     Added in version 3.8.

     Deprecated since version 3.12.

 -- Class: asyncio.SafeChildWatcher

     This implementation uses active event loop from the main thread to
     handle ‘SIGCHLD’ signal.  If the main thread has no running event
     loop another thread cannot spawn a subprocess (*note RuntimeError:
     195. is raised).

     The watcher avoids disrupting other code spawning processes by
     polling every process explicitly on a ‘SIGCHLD’ signal.

     This solution is as safe as *note MultiLoopChildWatcher: 2ba. and
     has the same 'O'('n') complexity but requires a running event loop
     in the main thread to work.

     Deprecated since version 3.12.

 -- Class: asyncio.FastChildWatcher

     This implementation reaps every terminated processes by calling
     ‘os.waitpid(-1)’ directly, possibly breaking other code spawning
     processes and waiting for their termination.

     There is no noticeable overhead when handling a big number of
     children ('O'(1) each time a child terminates).

     This solution requires a running event loop in the main thread to
     work, as *note SafeChildWatcher: 2bd.

     Deprecated since version 3.12.

 -- Class: asyncio.PidfdChildWatcher

     This implementation polls process file descriptors (pidfds) to
     await child process termination.  In some respects,
     ‘PidfdChildWatcher’ is a “Goldilocks” child watcher implementation.
     It doesn’t require signals or threads, doesn’t interfere with any
     processes launched outside the event loop, and scales linearly with
     the number of subprocesses launched by the event loop.  The main
     disadvantage is that pidfds are specific to Linux, and only work on
     recent (5.3+) kernels.

     Added in version 3.9.


File: python.info,  Node: Custom Policies,  Prev: Process Watchers,  Up: Policies

5.19.1.106 Custom Policies
..........................

To implement a new event loop policy, it is recommended to subclass
*note DefaultEventLoopPolicy: 35e1. and override the methods for which
custom behavior is wanted, e.g.:

     class MyEventLoopPolicy(asyncio.DefaultEventLoopPolicy):

         def get_event_loop(self):
             """Get the event loop.

             This may be None or an instance of EventLoop.
             """
             loop = super().get_event_loop()
             # Do something with loop ...
             return loop

     asyncio.set_event_loop_policy(MyEventLoopPolicy())


File: python.info,  Node: Platform Support,  Next: Extending,  Prev: Policies,  Up: asyncio — Asynchronous I/O

5.19.1.107 Platform Support
...........................

The *note asyncio: a. module is designed to be portable, but some
platforms have subtle differences and limitations due to the platforms’
underlying architecture and capabilities.

* Menu:

* All Platforms::
* Windows: Windows<82>.
* macOS: macOS<52>.


File: python.info,  Node: All Platforms,  Next: Windows<82>,  Up: Platform Support

5.19.1.108 All Platforms
........................

   * *note loop.add_reader(): 34f0. and *note loop.add_writer(): 356f.
     cannot be used to monitor file I/O.


File: python.info,  Node: Windows<82>,  Next: macOS<52>,  Prev: All Platforms,  Up: Platform Support

5.19.1.109 Windows
..................

'Source code:' Lib/asyncio/proactor_events.py(1),
Lib/asyncio/windows_events.py(2), Lib/asyncio/windows_utils.py(3)

__________________________________________________________________

Changed in version 3.8: On Windows, *note ProactorEventLoop: 60c. is now
the default event loop.

All event loops on Windows do not support the following methods:

   * *note loop.create_unix_connection(): 34d5. and *note
     loop.create_unix_server(): 1ae. are not supported.  The *note
     socket.AF_UNIX: 1955. socket family is specific to Unix.

   * *note loop.add_signal_handler(): 3578. and *note
     loop.remove_signal_handler(): 3579. are not supported.

*note SelectorEventLoop: 60b. has the following limitations:

   * *note SelectSelector: 35ef. is used to wait on socket events: it
     supports sockets and is limited to 512 sockets.

   * *note loop.add_reader(): 34f0. and *note loop.add_writer(): 356f.
     only accept socket handles (e.g.  pipe file descriptors are not
     supported).

   * Pipes are not supported, so the *note loop.connect_read_pipe():
     351c. and *note loop.connect_write_pipe(): 351d. methods are not
     implemented.

   * *note Subprocesses: 3490. are not supported, i.e.  *note
     loop.subprocess_exec(): 3519. and *note loop.subprocess_shell():
     351a. methods are not implemented.

*note ProactorEventLoop: 60c. has the following limitations:

   * The *note loop.add_reader(): 34f0. and *note loop.add_writer():
     356f. methods are not supported.

The resolution of the monotonic clock on Windows is usually around 15.6
milliseconds.  The best resolution is 0.5 milliseconds.  The resolution
depends on the hardware (availability of HPET(4)) and on the Windows
configuration.

* Menu:

* Subprocess Support on Windows::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/proactor_events.py

   (2) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/windows_events.py

   (3) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/windows_utils.py

   (4) https://en.wikipedia.org/wiki/High_Precision_Event_Timer


File: python.info,  Node: Subprocess Support on Windows,  Up: Windows<82>

5.19.1.110 Subprocess Support on Windows
........................................

On Windows, the default event loop *note ProactorEventLoop: 60c.
supports subprocesses, whereas *note SelectorEventLoop: 60b. does not.

The *note policy.set_child_watcher(): 2c0. function is also not
supported, as *note ProactorEventLoop: 60c. has a different mechanism to
watch child processes.


File: python.info,  Node: macOS<52>,  Prev: Windows<82>,  Up: Platform Support

5.19.1.111 macOS
................

Modern macOS versions are fully supported.

macOS <= 10.8
.............

On macOS 10.6, 10.7 and 10.8, the default event loop uses *note
selectors.KqueueSelector: 35f2, which does not support character devices
on these versions.  The *note SelectorEventLoop: 60b. can be manually
configured to use *note SelectSelector: 35ef. or *note PollSelector:
bf7. to support character devices on these older versions of macOS.
Example:

     import asyncio
     import selectors

     selector = selectors.SelectSelector()
     loop = asyncio.SelectorEventLoop(selector)
     asyncio.set_event_loop(loop)


File: python.info,  Node: Extending,  Next: High-level API Index,  Prev: Platform Support,  Up: asyncio — Asynchronous I/O

5.19.1.112 Extending
....................

The main direction for *note asyncio: a. extending is writing custom
'event loop' classes.  Asyncio has helpers that could be used to
simplify this task.

     Note: Third-parties should reuse existing asyncio code with
     caution, a new Python version is free to break backward
     compatibility in 'internal' part of API.

* Menu:

* Writing a Custom Event Loop::
* Future and Task private constructors::
* Task lifetime support::


File: python.info,  Node: Writing a Custom Event Loop,  Next: Future and Task private constructors,  Up: Extending

5.19.1.113 Writing a Custom Event Loop
......................................

*note asyncio.AbstractEventLoop: 969. declares very many methods.
Implementing all them from scratch is a tedious job.

A loop can get many common methods implementation for free by inheriting
from ‘asyncio.BaseEventLoop’.

In turn, the successor should implement a bunch of 'private' methods
declared but not implemented in ‘asyncio.BaseEventLoop’.

For example, ‘loop.create_connection()’ checks arguments, resolves DNS
addresses, and calls ‘loop._make_socket_transport()’ that should be
implemented by inherited class.  The ‘_make_socket_transport()’ method
is not documented and is considered as an 'internal' API.


File: python.info,  Node: Future and Task private constructors,  Next: Task lifetime support,  Prev: Writing a Custom Event Loop,  Up: Extending

5.19.1.114 Future and Task private constructors
...............................................

*note asyncio.Future: bec. and *note asyncio.Task: 1be. should be never
created directly, please use corresponding *note loop.create_future():
c9b. and *note loop.create_task(): 1c0, or *note asyncio.create_task():
1bf. factories instead.

However, third-party 'event loops' may 'reuse' built-in future and task
implementations for the sake of getting a complex and highly optimized
code for free.

For this purpose the following, 'private' constructors are listed:

 -- Method: Future.__init__ (*, loop=None)

     Create a built-in future instance.

     'loop' is an optional event loop instance.

 -- Method: Task.__init__ (coro, *, loop=None, name=None, context=None)

     Create a built-in task instance.

     'loop' is an optional event loop instance.  The rest of arguments
     are described in *note loop.create_task(): 1c0. description.

     Changed in version 3.11: 'context' argument is added.


File: python.info,  Node: Task lifetime support,  Prev: Future and Task private constructors,  Up: Extending

5.19.1.115 Task lifetime support
................................

A third party task implementation should call the following functions to
keep a task visible by *note asyncio.all_tasks(): 960. and *note
asyncio.current_task(): 480.:

 -- Function: asyncio._register_task (task)

     Register a new 'task' as managed by 'asyncio'.

     Call the function from a task constructor.

 -- Function: asyncio._unregister_task (task)

     Unregister a 'task' from 'asyncio' internal structures.

     The function should be called when a task is about to finish.

 -- Function: asyncio._enter_task (loop, task)

     Switch the current task to the 'task' argument.

     Call the function just before executing a portion of embedded
     'coroutine' (*note coroutine.send(): 217c. or *note
     coroutine.throw(): 4fa.).

 -- Function: asyncio._leave_task (loop, task)

     Switch the current task back from 'task' to ‘None’.

     Call the function just after *note coroutine.send(): 217c. or *note
     coroutine.throw(): 4fa. execution.


File: python.info,  Node: High-level API Index,  Next: Low-level API Index,  Prev: Extending,  Up: asyncio — Asynchronous I/O

5.19.1.116 High-level API Index
...............................

This page lists all high-level async/await enabled asyncio APIs.

* Menu:

* Tasks::
* Queues: Queues<2>.
* Subprocesses: Subprocesses<2>.
* Streams: Streams<2>.
* Synchronization::
* Exceptions: Exceptions<14>.


File: python.info,  Node: Tasks,  Next: Queues<2>,  Up: High-level API Index

5.19.1.117 Tasks
................

Utilities to run asyncio programs, create Tasks, and await on multiple
things with timeouts.

*note run(): 47f.                                      Create event loop, run a coroutine, close the loop.
                                                       
                                                       
*note Runner: 603.                                     A context manager that simplifies multiple async
                                                       function calls.
                                                       
                                                       
*note Task: 1be.                                       Task object.
                                                       
                                                       
*note TaskGroup: 1b5.                                  A context manager that holds a group of tasks.
                                                       Provides a convenient and reliable way to wait for
                                                       all tasks in the group to finish.
                                                       
                                                       
*note create_task(): 1bf.                              Start an asyncio Task, then returns it.
                                                       
                                                       
*note current_task(): 480.                             Return the current Task.
                                                       
                                                       
*note all_tasks(): 960.                                Return all tasks that are not yet finished for an
                                                       event loop.
                                                       
                                                       
‘await’ *note sleep(): a7e.                            Sleep for a number of seconds.
                                                       
                                                       
‘await’ *note gather(): 600.                           Schedule and wait for things concurrently.
                                                       
                                                       
‘await’ *note wait_for(): 602.                         Run with a timeout.
                                                       
                                                       
‘await’ *note shield(): a7f.                           Shield from cancellation.
                                                       
                                                       
‘await’ *note wait(): 482.                             Monitor for completion.
                                                       
                                                       
*note timeout(): 601.                                  Run with a timeout.  Useful in cases when ‘wait_for’
                                                       is not suitable.
                                                       
                                                       
*note to_thread(): 8f1.                                Asynchronously run a function in a separate OS
                                                       thread.
                                                       
                                                       
*note run_coroutine_threadsafe(): 889.                 Schedule a coroutine from another OS thread.
                                                       
                                                       
‘for in’ *note as_completed(): 1aa.                    Monitor for completion with a ‘for’ loop.
                                                       

Examples
........

   * *note Using asyncio.gather() to run things in parallel: 34af.

   * *note Using asyncio.wait_for() to enforce a timeout: 34b7.

   * *note Cancellation: 34cc.

   * *note Using asyncio.sleep(): 34ad.

   * See also the main *note Tasks documentation page: 348e.


File: python.info,  Node: Queues<2>,  Next: Subprocesses<2>,  Prev: Tasks,  Up: High-level API Index

5.19.1.118 Queues
.................

Queues should be used to distribute work amongst multiple asyncio Tasks,
implement connection pools, and pub/sub patterns.

*note Queue: a85.                                      A FIFO queue.
                                                       
                                                       
*note PriorityQueue: 3540.                             A priority queue.
                                                       
                                                       
*note LifoQueue: 3542.                                 A LIFO queue.
                                                       

Examples
........

   * *note Using asyncio.Queue to distribute workload between several
     Tasks: 3544.

   * See also the *note Queues documentation page: 3491.


File: python.info,  Node: Subprocesses<2>,  Next: Streams<2>,  Prev: Queues<2>,  Up: High-level API Index

5.19.1.119 Subprocesses
.......................

Utilities to spawn subprocesses and run shell commands.

‘await’ *note create_subprocess_exec(): a86.           Create a subprocess.
                                                       
                                                       
‘await’ *note create_subprocess_shell(): a87.          Run a shell command.
                                                       

Examples
........

   * *note Executing a shell command: 3513.

   * See also the *note subprocess APIs: 3490. documentation.


File: python.info,  Node: Streams<2>,  Next: Synchronization,  Prev: Subprocesses<2>,  Up: High-level API Index

5.19.1.120 Streams
..................

High-level APIs to work with network IO.

‘await’ *note open_connection(): b31.                  Establish a TCP connection.
                                                       
                                                       
‘await’ *note open_unix_connection(): 34d4.            Establish a Unix socket connection.
                                                       
                                                       
‘await’ *note start_server(): b32.                     Start a TCP server.
                                                       
                                                       
‘await’ *note start_unix_server(): 34d6.               Start a Unix socket server.
                                                       
                                                       
*note StreamReader: 15b6.                              High-level async/await object to receive network
                                                       data.
                                                       
                                                       
*note StreamWriter: 180f.                              High-level async/await object to send network data.
                                                       

Examples
........

   * *note Example TCP client: 34d0.

   * See also the *note streams APIs: 348f. documentation.


File: python.info,  Node: Synchronization,  Next: Exceptions<14>,  Prev: Streams<2>,  Up: High-level API Index

5.19.1.121 Synchronization
..........................

Threading-like synchronization primitives that can be used in Tasks.

*note Lock: a80.                                       A mutex lock.
                                                       
                                                       
*note Event: a81.                                      An event object.
                                                       
                                                       
*note Condition: a82.                                  A condition object.
                                                       
                                                       
*note Semaphore: a83.                                  A semaphore.
                                                       
                                                       
*note BoundedSemaphore: a84.                           A bounded semaphore.
                                                       
                                                       
*note Barrier: 604.                                    A barrier object.
                                                       

Examples
........

   * *note Using asyncio.Event: 34fc.

   * *note Using asyncio.Barrier: 350a.

   * See also the documentation of asyncio *note synchronization
     primitives: 3492.


File: python.info,  Node: Exceptions<14>,  Prev: Synchronization,  Up: High-level API Index

5.19.1.122 Exceptions
.....................

*note asyncio.CancelledError: 1b8.                     Raised when a Task is cancelled.  See also
                                                       *note Task.cancel(): 1b7.
                                                       
                                                       
*note asyncio.BrokenBarrierError: 605.                 Raised when a Barrier is broken.  See also
                                                       *note Barrier.wait(): 3509.
                                                       

Examples
........

   * *note Handling CancelledError to run code on cancellation request:
     34cc.

   * See also the full list of *note asyncio-specific exceptions: 3546.


File: python.info,  Node: Low-level API Index,  Next: Developing with asyncio,  Prev: High-level API Index,  Up: asyncio — Asynchronous I/O

5.19.1.123 Low-level API Index
..............................

This page lists all low-level asyncio APIs.

* Menu:

* Obtaining the Event Loop::
* Event Loop Methods::
* Transports: Transports<2>.
* Protocols: Protocols<2>.
* Event Loop Policies::


File: python.info,  Node: Obtaining the Event Loop,  Next: Event Loop Methods,  Up: Low-level API Index

5.19.1.124 Obtaining the Event Loop
...................................

*note asyncio.get_running_loop(): b24.                 The 'preferred' function to get the running event
                                                       loop.
                                                       
                                                       
*note asyncio.get_event_loop(): 2c2.                   Get an event loop instance (running or current via
                                                       the current policy).
                                                       
                                                       
*note asyncio.set_event_loop(): 18fa.                  Set the event loop as current via the current
                                                       policy.
                                                       
                                                       
*note asyncio.new_event_loop(): 349c.                  Create a new event loop.
                                                       

Examples
........

   * *note Using asyncio.get_running_loop(): 359a.


File: python.info,  Node: Event Loop Methods,  Next: Transports<2>,  Prev: Obtaining the Event Loop,  Up: Low-level API Index

5.19.1.125 Event Loop Methods
.............................

See also the main documentation section about the *note Event loop
methods: 3555.

Lifecycle
.........

*note loop.run_until_complete(): c99.                  Run a Future/Task/awaitable until complete.
                                                       
                                                       
*note loop.run_forever(): 3557.                        Run the event loop forever.
                                                       
                                                       
*note loop.stop(): c9e.                                Stop the event loop.
                                                       
                                                       
*note loop.close(): 3559.                              Close the event loop.
                                                       
                                                       
*note loop.is_running(): 3558.                         Return ‘True’ if the event loop is running.
                                                       
                                                       
*note loop.is_closed(): df2.                           Return ‘True’ if the event loop is closed.
                                                       
                                                       
‘await’ *note loop.shutdown_asyncgens(): ca0.          Close asynchronous generators.
                                                       

Debugging
.........

*note loop.set_debug(): df0.                           Enable or disable the debug mode.
                                                       
                                                       
*note loop.get_debug(): df1.                           Get the current debug mode.
                                                       

Scheduling Callbacks
....................

*note loop.call_soon(): b1d.                           Invoke a callback soon.
                                                       
                                                       
*note loop.call_soon_threadsafe(): b1e.                A thread-safe variant of
                                                       *note loop.call_soon(): b1d.
                                                       
                                                       
*note loop.call_later(): b1f.                          Invoke a callback 'after' the given time.
                                                       
                                                       
*note loop.call_at(): b20.                             Invoke a callback 'at' the given time.
                                                       

Thread/Process Pool
...................

‘await’ *note loop.run_in_executor(): 8f2.             Run a CPU-bound or other blocking function in a
                                                       *note concurrent.futures: 21. executor.
                                                       
                                                       
*note loop.set_default_executor(): 746.                Set the default executor for
                                                       *note loop.run_in_executor(): 8f2.
                                                       

Tasks and Futures
.................

*note loop.create_future(): c9b.                       Create a *note Future: bec. object.
                                                       
                                                       
*note loop.create_task(): 1c0.                         Schedule coroutine as a *note Task: 1be.
                                                       
                                                       
*note loop.set_task_factory(): df4.                    Set a factory used by *note loop.create_task(): 1c0.
                                                       to create *note Tasks: 1be.
                                                       
                                                       
*note loop.get_task_factory(): df5.                    Get the factory *note loop.create_task(): 1c0. uses
                                                       to create *note Tasks: 1be.
                                                       

DNS
...

‘await’ *note loop.getaddrinfo(): c34.                 Asynchronous version of
                                                       *note socket.getaddrinfo(): 15ba.
                                                       
                                                       
‘await’ *note loop.getnameinfo(): c35.                 Asynchronous version of
                                                       *note socket.getnameinfo(): 17d3.
                                                       

Networking and IPC
..................

‘await’ *note loop.create_connection(): 606.           Open a TCP connection.
                                                       
                                                       
‘await’ *note loop.create_server(): b2c.               Create a TCP server.
                                                       
                                                       
‘await’ *note loop.create_unix_connection(): 34d5.     Open a Unix socket connection.
                                                       
                                                       
‘await’ *note loop.create_unix_server(): 1ae.          Create a Unix socket server.
                                                       
                                                       
‘await’ *note loop.connect_accepted_socket(): 7e2.     Wrap a *note socket: dcf. into a ‘(transport,
                                                       protocol)’ pair.
                                                       
                                                       
‘await’ *note loop.create_datagram_endpoint(): 736.    Open a datagram (UDP) connection.
                                                       
                                                       
‘await’ *note loop.sendfile(): 356b.                   Send a file over a transport.
                                                       
                                                       
‘await’ *note loop.start_tls(): b22.                   Upgrade an existing connection to TLS.
                                                       
                                                       
‘await’ *note loop.connect_read_pipe(): 351c.          Wrap a read end of a pipe into a ‘(transport,
                                                       protocol)’ pair.
                                                       
                                                       
‘await’ *note loop.connect_write_pipe(): 351d.         Wrap a write end of a pipe into a ‘(transport,
                                                       protocol)’ pair.
                                                       

Sockets
.......

‘await’ *note loop.sock_recv(): c31.                   Receive data from the *note socket: dcf.
                                                       
                                                       
‘await’ *note loop.sock_recv_into(): b23.              Receive data from the *note socket: dcf. into a
                                                       buffer.
                                                       
                                                       
‘await’ *note loop.sock_recvfrom(): 609.               Receive a datagram from the *note socket: dcf.
                                                       
                                                       
‘await’ *note loop.sock_recvfrom_into(): 60a.          Receive a datagram from the *note socket: dcf. into
                                                       a buffer.
                                                       
                                                       
‘await’ *note loop.sock_sendall(): c32.                Send data to the *note socket: dcf.
                                                       
                                                       
‘await’ *note loop.sock_sendto(): 608.                 Send a datagram via the *note socket: dcf. to the
                                                       given address.
                                                       
                                                       
‘await’ *note loop.sock_connect(): df8.                Connect the *note socket: dcf.
                                                       
                                                       
‘await’ *note loop.sock_accept(): c33.                 Accept a *note socket: dcf. connection.
                                                       
                                                       
‘await’ *note loop.sock_sendfile(): b27.               Send a file over the *note socket: dcf.
                                                       
                                                       
*note loop.add_reader(): 34f0.                         Start watching a file descriptor for read
                                                       availability.
                                                       
                                                       
*note loop.remove_reader(): 356e.                      Stop watching a file descriptor for read
                                                       availability.
                                                       
                                                       
*note loop.add_writer(): 356f.                         Start watching a file descriptor for write
                                                       availability.
                                                       
                                                       
*note loop.remove_writer(): 3570.                      Stop watching a file descriptor for write
                                                       availability.
                                                       

Unix Signals
............

*note loop.add_signal_handler(): 3578.                 Add a handler for a *note signal: c6.
                                                       
                                                       
*note loop.remove_signal_handler(): 3579.              Remove a handler for a *note signal: c6.
                                                       

Subprocesses
............

*note loop.subprocess_exec(): 3519.                    Spawn a subprocess.
                                                       
                                                       
*note loop.subprocess_shell(): 351a.                   Spawn a subprocess from a shell command.
                                                       

Error Handling
..............

*note loop.call_exception_handler(): 357d.             Call the exception handler.
                                                       
                                                       
*note loop.set_exception_handler(): 357c.              Set a new exception handler.
                                                       
                                                       
*note loop.get_exception_handler(): c9c.               Get the current exception handler.
                                                       
                                                       
*note loop.default_exception_handler(): 357e.          The default exception handler implementation.
                                                       

Examples
........

   * *note Using asyncio.new_event_loop() and loop.run_forever(): 3589.

   * *note Using loop.call_later(): 358b.

   * Using ‘loop.create_connection()’ to implement *note an echo-client:
     34e7.

   * Using ‘loop.create_connection()’ to *note connect a socket: 34ee.

   * *note Using add_reader() to watch an FD for read events: 34ef.

   * *note Using loop.add_signal_handler(): 358e.

   * *note Using loop.subprocess_exec(): 352f.


File: python.info,  Node: Transports<2>,  Next: Protocols<2>,  Prev: Event Loop Methods,  Up: Low-level API Index

5.19.1.126 Transports
.....................

All transports implement the following methods:

*note transport.close(): 3565.                         Close the transport.
                                                       
                                                       
*note transport.is_closing(): c9a.                     Return ‘True’ if the transport is closing or is
                                                       closed.
                                                       
                                                       
*note transport.get_extra_info(): ab1.                 Request for information about the transport.
                                                       
                                                       
*note transport.set_protocol(): 35ab.                  Set a new protocol.
                                                       
                                                       
*note transport.get_protocol(): 35ac.                  Return the current protocol.
                                                       

Transports that can receive data (TCP and Unix connections, pipes, etc).
Returned from methods like *note loop.create_connection(): 606, *note
loop.create_unix_connection(): 34d5, *note loop.connect_read_pipe():
351c, etc:

Read Transports
...............

*note transport.is_reading(): b34.                     Return ‘True’ if the transport is receiving.
                                                       
                                                       
*note transport.pause_reading(): b36.                  Pause receiving.
                                                       
                                                       
*note transport.resume_reading(): b35.                 Resume receiving.
                                                       

Transports that can Send data (TCP and Unix connections, pipes, etc).
Returned from methods like *note loop.create_connection(): 606, *note
loop.create_unix_connection(): 34d5, *note loop.connect_write_pipe():
351d, etc:

Write Transports
................

*note transport.write(): 1601.                         Write data to the transport.
                                                       
                                                       
*note transport.writelines(): 1600.                    Write buffers to the transport.
                                                       
                                                       
*note transport.can_write_eof(): 35af.                 Return *note True: c2d. if the transport supports
                                                       sending EOF.
                                                       
                                                       
*note transport.write_eof(): 35b0.                     Close and send EOF after flushing buffered data.
                                                       
                                                       
*note transport.abort(): 3586.                         Close the transport immediately.
                                                       
                                                       
*note transport.get_write_buffer_size(): 35b1.         Return the current size of the output buffer.
                                                       
                                                       
*note transport.get_write_buffer_limits(): df3.        Return high and low water marks for write flow
                                                       control.
                                                       
                                                       
*note transport.set_write_buffer_limits(): 35b2.       Set new high and low water marks for write flow
                                                       control.
                                                       

Transports returned by *note loop.create_datagram_endpoint(): 736.:

Datagram Transports
...................

*note transport.sendto(): 1af.                         Send data to the remote peer.
                                                       
                                                       
*note transport.abort(): 35b6.                         Close the transport immediately.
                                                       

Low-level transport abstraction over subprocesses.  Returned by *note
loop.subprocess_exec(): 3519. and *note loop.subprocess_shell(): 351a.:

Subprocess Transports
.....................

*note transport.get_pid(): 35b8.                       Return the subprocess process id.
                                                       
                                                       
*note transport.get_pipe_transport(): 35b9.            Return the transport for the requested communication
                                                       pipe ('stdin', 'stdout', or 'stderr').
                                                       
                                                       
*note transport.get_returncode(): 35ba.                Return the subprocess return code.
                                                       
                                                       
*note transport.kill(): 35bb.                          Kill the subprocess.
                                                       
                                                       
*note transport.send_signal(): 35bd.                   Send a signal to the subprocess.
                                                       
                                                       
*note transport.terminate(): 35bc.                     Stop the subprocess.
                                                       
                                                       
*note transport.close(): 35be.                         Kill the subprocess and close all pipes.
                                                       


File: python.info,  Node: Protocols<2>,  Next: Event Loop Policies,  Prev: Transports<2>,  Up: Low-level API Index

5.19.1.127 Protocols
....................

Protocol classes can implement the following 'callback methods':

‘callback’ *note connection_made(): 3563.              Called when a connection is made.
                                                       
                                                       
‘callback’ *note connection_lost(): 35a7.              Called when the connection is lost or closed.
                                                       
                                                       
‘callback’ *note pause_writing(): 35b3.                Called when the transport’s buffer goes over the
                                                       high water mark.
                                                       
                                                       
‘callback’ *note resume_writing(): 35b4.               Called when the transport’s buffer drains below the
                                                       low water mark.
                                                       

Streaming Protocols (TCP, Unix Sockets, Pipes)
..............................................

‘callback’ *note data_received(): 18a5.                Called when some data is received.
                                                       
                                                       
‘callback’ *note eof_received(): 35c2.                 Called when an EOF is received.
                                                       

Buffered Streaming Protocols
............................

‘callback’ *note get_buffer(): 35c4.                   Called to allocate a new receive buffer.
                                                       
                                                       
‘callback’ *note buffer_updated(): 35c5.               Called when the buffer was updated with the received
                                                       data.
                                                       
                                                       
‘callback’ *note eof_received(): 35c6.                 Called when an EOF is received.
                                                       

Datagram Protocols
..................

‘callback’ *note datagram_received(): 35c8.            Called when a datagram is received.
                                                       
                                                       
‘callback’ *note error_received(): 35c9.               Called when a previous send or receive operation
                                                       raises an *note OSError: 41a.
                                                       

Subprocess Protocols
....................

‘callback’ *note pipe_data_received(): 18f4.           Called when the child process writes data into its
                                                       'stdout' or 'stderr' pipe.
                                                       
                                                       
‘callback’ *note pipe_connection_lost(): 35cb.         Called when one of the pipes communicating with the
                                                       child process is closed.
                                                       
                                                       
‘callback’ *note process_exited(): 18f3.               Called when the child process has exited.  It can be
                                                       called before *note pipe_data_received(): 18f4. and
                                                       *note pipe_connection_lost(): 35cb. methods.
                                                       


File: python.info,  Node: Event Loop Policies,  Prev: Protocols<2>,  Up: Low-level API Index

5.19.1.128 Event Loop Policies
..............................

Policies is a low-level mechanism to alter the behavior of functions
like *note asyncio.get_event_loop(): 2c2.  See also the main *note
policies section: 354f. for more details.

Accessing Policies
..................

*note asyncio.get_event_loop_policy(): 35db.           Return the current process-wide policy.
                                                       
                                                       
*note asyncio.set_event_loop_policy(): 35dc.           Set a new process-wide policy.
                                                       
                                                       
*note AbstractEventLoopPolicy: 35d9.                   Base class for policy objects.
                                                       


File: python.info,  Node: Developing with asyncio,  Prev: Low-level API Index,  Up: asyncio — Asynchronous I/O

5.19.1.129 Developing with asyncio
..................................

Asynchronous programming is different from classic “sequential”
programming.

This page lists common mistakes and traps and explains how to avoid
them.

* Menu:

* Debug Mode::
* Concurrency and Multithreading::
* Running Blocking Code::
* Logging: Logging<3>.
* Detect never-awaited coroutines::
* Detect never-retrieved exceptions::
* Asynchronous generators best practices::


File: python.info,  Node: Debug Mode,  Next: Concurrency and Multithreading,  Up: Developing with asyncio

5.19.1.130 Debug Mode
.....................

By default asyncio runs in production mode.  In order to ease the
development asyncio has a 'debug mode'.

There are several ways to enable asyncio debug mode:

   * Setting the *note PYTHONASYNCIODEBUG: 1ef1. environment variable to
     ‘1’.

   * Using the *note Python Development Mode: 1f8.

   * Passing ‘debug=True’ to *note asyncio.run(): 47f.

   * Calling *note loop.set_debug(): df0.

In addition to enabling the debug mode, consider also:

   * setting the log level of the *note asyncio logger: 3614. to *note
     logging.DEBUG: 1e95, for example the following snippet of code can
     be run at startup of the application:

          logging.basicConfig(level=logging.DEBUG)

   * configuring the *note warnings: 112. module to display *note
     ResourceWarning: 244. warnings.  One way of doing that is by using
     the *note -W: 8d0. ‘default’ command line option.

When the debug mode is enabled:

   * Many non-threadsafe asyncio APIs (such as *note loop.call_soon():
     b1d. and *note loop.call_at(): b20. methods) raise an exception if
     they are called from a wrong thread.

   * The execution time of the I/O selector is logged if it takes too
     long to perform an I/O operation.

   * Callbacks taking longer than 100 milliseconds are logged.  The
     *note loop.slow_callback_duration: 3580. attribute can be used to
     set the minimum execution duration in seconds that is considered
     “slow”.


File: python.info,  Node: Concurrency and Multithreading,  Next: Running Blocking Code,  Prev: Debug Mode,  Up: Developing with asyncio

5.19.1.131 Concurrency and Multithreading
.........................................

An event loop runs in a thread (typically the main thread) and executes
all callbacks and Tasks in its thread.  While a Task is running in the
event loop, no other Tasks can run in the same thread.  When a Task
executes an ‘await’ expression, the running Task gets suspended, and the
event loop executes the next Task.

To schedule a *note callback: 2aee. from another OS thread, the *note
loop.call_soon_threadsafe(): b1e. method should be used.  Example:

     loop.call_soon_threadsafe(callback, *args)

Almost all asyncio objects are not thread safe, which is typically not a
problem unless there is code that works with them from outside of a Task
or a callback.  If there’s a need for such code to call a low-level
asyncio API, the *note loop.call_soon_threadsafe(): b1e. method should
be used, e.g.:

     loop.call_soon_threadsafe(fut.cancel)

To schedule a coroutine object from a different OS thread, the *note
run_coroutine_threadsafe(): 889. function should be used.  It returns a
*note concurrent.futures.Future: 11f6. to access the result:

     async def coro_func():
          return await asyncio.sleep(1, 42)

     # Later in another OS thread:

     future = asyncio.run_coroutine_threadsafe(coro_func(), loop)
     # Wait for the result:
     result = future.result()

To handle signals the event loop must be run in the main thread.

The *note loop.run_in_executor(): 8f2. method can be used with a *note
concurrent.futures.ThreadPoolExecutor: 745. to execute blocking code in
a different OS thread without blocking the OS thread that the event loop
runs in.

There is currently no way to schedule coroutines or callbacks directly
from a different process (such as one started with *note
multiprocessing: 94.).  The *note Event loop methods: 3555. section
lists APIs that can read from pipes and watch file descriptors without
blocking the event loop.  In addition, asyncio’s *note Subprocess: 3490.
APIs provide a way to start a process and communicate with it from the
event loop.  Lastly, the aforementioned *note loop.run_in_executor():
8f2. method can also be used with a *note
concurrent.futures.ProcessPoolExecutor: 8f7. to execute code in a
different process.


File: python.info,  Node: Running Blocking Code,  Next: Logging<3>,  Prev: Concurrency and Multithreading,  Up: Developing with asyncio

5.19.1.132 Running Blocking Code
................................

Blocking (CPU-bound) code should not be called directly.  For example,
if a function performs a CPU-intensive calculation for 1 second, all
concurrent asyncio Tasks and IO operations would be delayed by 1 second.

An executor can be used to run a task in a different thread or even in a
different process to avoid blocking the OS thread with the event loop.
See the *note loop.run_in_executor(): 8f2. method for more details.


File: python.info,  Node: Logging<3>,  Next: Detect never-awaited coroutines,  Prev: Running Blocking Code,  Up: Developing with asyncio

5.19.1.133 Logging
..................

asyncio uses the *note logging: 87. module and all logging is performed
via the ‘"asyncio"’ logger.

The default log level is *note logging.INFO: 1e96, which can be easily
adjusted:

     logging.getLogger("asyncio").setLevel(logging.WARNING)

Network logging can block the event loop.  It is recommended to use a
separate thread for handling logs or use non-blocking IO. For example,
see *note Dealing with handlers that block: 3619.


File: python.info,  Node: Detect never-awaited coroutines,  Next: Detect never-retrieved exceptions,  Prev: Logging<3>,  Up: Developing with asyncio

5.19.1.134 Detect never-awaited coroutines
..........................................

When a coroutine function is called, but not awaited (e.g.  ‘coro()’
instead of ‘await coro()’) or the coroutine is not scheduled with *note
asyncio.create_task(): 1bf, asyncio will emit a *note RuntimeWarning:
1bd.:

     import asyncio

     async def test():
         print("never scheduled")

     async def main():
         test()

     asyncio.run(main())

Output:

     test.py:7: RuntimeWarning: coroutine 'test' was never awaited
       test()

Output in debug mode:

     test.py:7: RuntimeWarning: coroutine 'test' was never awaited
     Coroutine created at (most recent call last)
       File "../t.py", line 9, in <module>
         asyncio.run(main(), debug=True)

       < .. >

       File "../t.py", line 7, in main
         test()
       test()

The usual fix is to either await the coroutine or call the *note
asyncio.create_task(): 1bf. function:

     async def main():
         await test()


File: python.info,  Node: Detect never-retrieved exceptions,  Next: Asynchronous generators best practices,  Prev: Detect never-awaited coroutines,  Up: Developing with asyncio

5.19.1.135 Detect never-retrieved exceptions
............................................

If a *note Future.set_exception(): c9f. is called but the Future object
is never awaited on, the exception would never be propagated to the user
code.  In this case, asyncio would emit a log message when the Future
object is garbage collected.

Example of an unhandled exception:

     import asyncio

     async def bug():
         raise Exception("not consumed")

     async def main():
         asyncio.create_task(bug())

     asyncio.run(main())

Output:

     Task exception was never retrieved
     future: <Task finished coro=<bug() done, defined at test.py:3>
       exception=Exception('not consumed')>

     Traceback (most recent call last):
       File "test.py", line 4, in bug
         raise Exception("not consumed")
     Exception: not consumed

*note Enable the debug mode: 1ef2. to get the traceback where the task
was created:

     asyncio.run(main(), debug=True)

Output in debug mode:

     Task exception was never retrieved
     future: <Task finished coro=<bug() done, defined at test.py:3>
         exception=Exception('not consumed') created at asyncio/tasks.py:321>

     source_traceback: Object created at (most recent call last):
       File "../t.py", line 9, in <module>
         asyncio.run(main(), debug=True)

     < .. >

     Traceback (most recent call last):
       File "../t.py", line 4, in bug
         raise Exception("not consumed")
     Exception: not consumed


File: python.info,  Node: Asynchronous generators best practices,  Prev: Detect never-retrieved exceptions,  Up: Developing with asyncio

5.19.1.136 Asynchronous generators best practices
.................................................

Writing correct and efficient asyncio code requires awareness of certain
pitfalls.  This section outlines essential best practices that can save
you hours of debugging.

* Menu:

* Close asynchronous generators explicitly::
* Create asynchronous generators only when the event loop is running::
* Avoid concurrent iteration and closure of the same generator::


File: python.info,  Node: Close asynchronous generators explicitly,  Next: Create asynchronous generators only when the event loop is running,  Up: Asynchronous generators best practices

5.19.1.137 Close asynchronous generators explicitly
...................................................

It is recommended to manually close the *note asynchronous generator:
361f.  If a generator exits early - for example, due to an exception
raised in the body of an ‘async for’ loop - its asynchronous cleanup
code may run in an unexpected context.  This can occur after the tasks
it depends on have completed, or during the event loop shutdown when the
async-generator’s garbage collection hook is called.

To avoid this, explicitly close the generator by calling its *note
aclose(): 8e1. method, or use the *note contextlib.aclosing(): 7f2.
context manager:

     import asyncio
     import contextlib

     async def gen():
       yield 1
       yield 2

     async def func():
       async with contextlib.aclosing(gen()) as g:
         async for x in g:
           break  # Don't iterate until the end

     asyncio.run(func())

As noted above, the cleanup code for these asynchronous generators is
deferred.  The following example demonstrates that the finalization of
an asynchronous generator can occur in an unexpected order:

     import asyncio
     work_done = False

     async def cursor():
         try:
             yield 1
         finally:
             assert work_done

     async def rows():
         global work_done
         try:
             yield 2
         finally:
             await asyncio.sleep(0.1) # immitate some async work
             work_done = True


     async def main():
         async for c in cursor():
             async for r in rows():
                 break
             break

     asyncio.run(main())

For this example, we get the following output:

     unhandled exception during asyncio.run() shutdown
     task: <Task finished name='Task-3' coro=<<async_generator_athrow without __name__>()> exception=AssertionError()>
     Traceback (most recent call last):
       File "example.py", line 6, in cursor
         yield 1
     asyncio.exceptions.CancelledError

     During handling of the above exception, another exception occurred:

     Traceback (most recent call last):
       File "example.py", line 8, in cursor
         assert work_done
                ^^^^^^^^^
     AssertionError

The ‘cursor()’ asynchronous generator was finalized before the ‘rows’
generator - an unexpected behavior.

The example can be fixed by explicitly closing the ‘cursor’ and ‘rows’
async-generators:

     async def main():
         async with contextlib.aclosing(cursor()) as cursor_gen:
             async for c in cursor_gen:
                 async with contextlib.aclosing(rows()) as rows_gen:
                     async for r in rows_gen:
                         break
                 break


File: python.info,  Node: Create asynchronous generators only when the event loop is running,  Next: Avoid concurrent iteration and closure of the same generator,  Prev: Close asynchronous generators explicitly,  Up: Asynchronous generators best practices

5.19.1.138 Create asynchronous generators only when the event loop is running
.............................................................................

It is recommended to create *note asynchronous generators: 361f. only
after the event loop has been created.

To ensure that asynchronous generators close reliably, the event loop
uses the *note sys.set_asyncgen_hooks(): 1730. function to register
callback functions.  These callbacks update the list of running
asynchronous generators to keep it in a consistent state.

When the *note loop.shutdown_asyncgens(): ca0. function is called, the
running generators are stopped gracefully and the list is cleared.

The asynchronous generator invokes the corresponding system hook during
its first iteration.  At the same time, the generator records that the
hook has been called and does not call it again.

Therefore, if iteration begins before the event loop is created, the
event loop will not be able to add the generator to its list of active
generators because the hooks are set after the generator attempts to
call them.  Consequently, the event loop will not be able to terminate
the generator if necessary.

Consider the following example:

     import asyncio

     async def agenfn():
         try:
             yield 10
         finally:
             await asyncio.sleep(0)


     with asyncio.Runner() as runner:
         agen = agenfn()
         print(runner.run(anext(agen)))
         del agen

Output:

     10
     Exception ignored while closing generator <async_generator object agenfn at 0x000002F71CD10D70>:
     Traceback (most recent call last):
       File "example.py", line 13, in <module>
         del agen
             ^^^^
     RuntimeError: async generator ignored GeneratorExit

This example can be fixed as follows:

     import asyncio

     async def agenfn():
         try:
             yield 10
         finally:
             await asyncio.sleep(0)

     async def main():
         agen = agenfn()
         print(await anext(agen))
         del agen

     asyncio.run(main())


File: python.info,  Node: Avoid concurrent iteration and closure of the same generator,  Prev: Create asynchronous generators only when the event loop is running,  Up: Asynchronous generators best practices

5.19.1.139 Avoid concurrent iteration and closure of the same generator
.......................................................................

Async generators may be reentered while another *note __anext__(): 21f7.
/ *note athrow(): 4fc. / *note aclose(): 8e1. call is in progress.  This
may lead to an inconsistent state of the async generator and can cause
errors.

Let’s consider the following example:

     import asyncio

     async def consumer():
         for idx in range(100):
             await asyncio.sleep(0)
             message = yield idx
             print('received', message)

     async def amain():
         agenerator = consumer()
         await agenerator.asend(None)

         fa = asyncio.create_task(agenerator.asend('A'))
         fb = asyncio.create_task(agenerator.asend('B'))
         await fa
         await fb

     asyncio.run(amain())

Output:

     received A
     Traceback (most recent call last):
       File "test.py", line 38, in <module>
         asyncio.run(amain())
         ~~~~~~~~~~~^^^^^^^^^
       File "Lib/asyncio/runners.py", line 204, in run
         return runner.run(main)
                ~~~~~~~~~~^^^^^^
       File "Lib/asyncio/runners.py", line 127, in run
         return self._loop.run_until_complete(task)
                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
       File "Lib/asyncio/base_events.py", line 719, in run_until_complete
         return future.result()
                ~~~~~~~~~~~~~^^
       File "test.py", line 36, in amain
         await fb
     RuntimeError: anext(): asynchronous generator is already running

Therefore, it is recommended to avoid using asynchronous generators in
parallel tasks or across multiple event loops.

     Note: The source code for asyncio can be found in Lib/asyncio/(1).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/asyncio/


File: python.info,  Node: socket — Low-level networking interface,  Next: ssl — TLS/SSL wrapper for socket objects,  Prev: asyncio — Asynchronous I/O,  Up: Networking and Interprocess Communication

5.19.2 ‘socket’ — Low-level networking interface
------------------------------------------------

'Source code:' Lib/socket.py(1)

__________________________________________________________________

This module provides access to the BSD 'socket' interface.  It is
available on all modern Unix systems, Windows, MacOS, and probably
additional platforms.

     Note: Some behavior may be platform dependent, since calls are made
     to the operating system socket APIs.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The Python interface is a straightforward transliteration of the Unix
system call and library interface for sockets to Python’s
object-oriented style: the *note socket(): dcf. function returns a
'socket object' whose methods implement the various socket system calls.
Parameter types are somewhat higher-level than in the C interface: as
with ‘read()’ and ‘write()’ operations on Python files, buffer
allocation on receive operations is automatic, and buffer length is
implicit on send operations.

See also
........

Module *note socketserver: cd.

     Classes that simplify writing network servers.

Module *note ssl: d0.

     A TLS/SSL wrapper for socket objects.

* Menu:

* Socket families::
* Module contents: Module contents<2>.
* Socket Objects::
* Notes on socket timeouts::
* Example: Example<7>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/socket.py


File: python.info,  Node: Socket families,  Next: Module contents<2>,  Up: socket — Low-level networking interface

5.19.2.1 Socket families
........................

Depending on the system and the build options, various socket families
are supported by this module.

The address format required by a particular socket object is
automatically selected based on the address family specified when the
socket object was created.  Socket addresses are represented as follows:

   - The address of an *note AF_UNIX: 1955. socket bound to a file
     system node is represented as a string, using the file system
     encoding and the ‘'surrogateescape'’ error handler (see PEP
     383(1)).  An address in Linux’s abstract namespace is returned as a
     *note bytes-like object: d55. with an initial null byte; note that
     sockets in this namespace can communicate with normal file system
     sockets, so programs intended to run on Linux may need to deal with
     both types of address.  A string or bytes-like object can be used
     for either type of address when passing it as an argument.

     Changed in version 3.3: Previously, *note AF_UNIX: 1955. socket
     paths were assumed to use UTF-8 encoding.

     Changed in version 3.5: Writable *note bytes-like object: d55. is
     now accepted.

   - A pair ‘(host, port)’ is used for the *note AF_INET: 1953. address
     family, where 'host' is a string representing either a hostname in
     internet domain notation like ‘'daring.cwi.nl'’ or an IPv4 address
     like ‘'100.50.200.5'’, and 'port' is an integer.

        - For IPv4 addresses, two special forms are accepted instead of
          a host address: ‘''’ represents ‘INADDR_ANY’, which is used to
          bind to all interfaces, and the string ‘'<broadcast>'’
          represents ‘INADDR_BROADCAST’.  This behavior is not
          compatible with IPv6, therefore, you may want to avoid these
          if you intend to support IPv6 with your Python programs.

   - For *note AF_INET6: 1954. address family, a four-tuple ‘(host,
     port, flowinfo, scope_id)’ is used, where 'flowinfo' and 'scope_id'
     represent the ‘sin6_flowinfo’ and ‘sin6_scope_id’ members in
     ‘struct sockaddr_in6’ in C. For ‘socket’ module methods, 'flowinfo'
     and 'scope_id' can be omitted just for backward compatibility.
     Note, however, omission of 'scope_id' can cause problems in
     manipulating scoped IPv6 addresses.

     Changed in version 3.7: For multicast addresses (with 'scope_id'
     meaningful) 'address' may not contain ‘%scope_id’ (or ‘zone id’)
     part.  This information is superfluous and may be safely omitted
     (recommended).

   - ‘AF_NETLINK’ sockets are represented as pairs ‘(pid, groups)’.

   - Linux-only support for TIPC is available using the ‘AF_TIPC’
     address family.  TIPC is an open, non-IP based networked protocol
     designed for use in clustered computer environments.  Addresses are
     represented by a tuple, and the fields depend on the address type.
     The general tuple form is ‘(addr_type, v1, v2, v3 [, scope])’,
     where:

        - 'addr_type' is one of ‘TIPC_ADDR_NAMESEQ’, ‘TIPC_ADDR_NAME’,
          or ‘TIPC_ADDR_ID’.

        - 'scope' is one of ‘TIPC_ZONE_SCOPE’, ‘TIPC_CLUSTER_SCOPE’, and
          ‘TIPC_NODE_SCOPE’.

        - If 'addr_type' is ‘TIPC_ADDR_NAME’, then 'v1' is the server
          type, 'v2' is the port identifier, and 'v3' should be 0.

          If 'addr_type' is ‘TIPC_ADDR_NAMESEQ’, then 'v1' is the server
          type, 'v2' is the lower port number, and 'v3' is the upper
          port number.

          If 'addr_type' is ‘TIPC_ADDR_ID’, then 'v1' is the node, 'v2'
          is the reference, and 'v3' should be set to 0.

   - A tuple ‘(interface, )’ is used for the *note AF_CAN: 3628. address
     family, where 'interface' is a string representing a network
     interface name like ‘'can0'’.  The network interface name ‘''’ can
     be used to receive packets from all network interfaces of this
     family.

        - *note CAN_ISOTP: 3629. protocol requires a tuple ‘(interface,
          rx_addr, tx_addr)’ where both additional parameters are
          unsigned long integer that represent a CAN identifier
          (standard or extended).

        - *note CAN_J1939: 93c. protocol requires a tuple ‘(interface,
          name, pgn, addr)’ where additional parameters are 64-bit
          unsigned integer representing the ECU name, a 32-bit unsigned
          integer representing the Parameter Group Number (PGN), and an
          8-bit integer representing the address.

   - A string or a tuple ‘(id, unit)’ is used for the ‘SYSPROTO_CONTROL’
     protocol of the ‘PF_SYSTEM’ family.  The string is the name of a
     kernel control using a dynamically assigned ID. The tuple can be
     used if ID and unit number of the kernel control are known or if a
     registered ID is used.

     Added in version 3.3.

   - ‘AF_BLUETOOTH’ supports the following protocols and address
     formats:

        - ‘BTPROTO_L2CAP’ accepts ‘(bdaddr, psm)’ where ‘bdaddr’ is the
          Bluetooth address as a string and ‘psm’ is an integer.

        - ‘BTPROTO_RFCOMM’ accepts ‘(bdaddr, channel)’ where ‘bdaddr’ is
          the Bluetooth address as a string and ‘channel’ is an integer.

        - ‘BTPROTO_HCI’ accepts a format that depends on your OS.

             - On Linux it accepts a tuple ‘(device_id,)’ where
               ‘device_id’ is an integer specifying the number of the
               Bluetooth device.

             - On FreeBSD, NetBSD and DragonFly BSD it accepts ‘bdaddr’
               where ‘bdaddr’ is the Bluetooth address as a string.

          Changed in version 3.2: NetBSD and DragonFlyBSD support added.

          Changed in version 3.13.3: FreeBSD support added.

        - ‘BTPROTO_SCO’ accepts ‘bdaddr’ where ‘bdaddr’ is the Bluetooth
          address as a string or a *note bytes: 1c2. object.  (ex.
          ‘'12:23:34:45:56:67'’ or ‘b'12:23:34:45:56:67'’) This protocol
          is not supported under FreeBSD.

   - *note AF_ALG: cfd. is a Linux-only socket based interface to Kernel
     cryptography.  An algorithm socket is configured with a tuple of
     two to four elements ‘(type, name [, feat [, mask]])’, where:

        - 'type' is the algorithm type as string, e.g.  ‘aead’, ‘hash’,
          ‘skcipher’ or ‘rng’.

        - 'name' is the algorithm name and operation mode as string,
          e.g.  ‘sha256’, ‘hmac(sha256)’, ‘cbc(aes)’ or
          ‘drbg_nopr_ctr_aes256’.

        - 'feat' and 'mask' are unsigned 32bit integers.

     *note Availability: 1ef7.: Linux >= 2.6.38.

     Some algorithm types require more recent Kernels.

     Added in version 3.6.

   - *note AF_VSOCK: b92. allows communication between virtual machines
     and their hosts.  The sockets are represented as a ‘(CID, port)’
     tuple where the context ID or CID and port are integers.

     *note Availability: 1ef7.: Linux >= 3.9

     See ‘vsock(7)(2)’

     Added in version 3.7.

   - *note AF_PACKET: 362a. is a low-level interface directly to network
     devices.  The addresses are represented by the tuple ‘(ifname,
     proto[, pkttype[, hatype[, addr]]])’ where:

        - 'ifname' - String specifying the device name.

        - 'proto' - The Ethernet protocol number.  May be *note
          ETH_P_ALL: 18c6. to capture all protocols, one of the *note
          ETHERTYPE_* constants: 18c7. or any other Ethernet protocol
          number.

        - 'pkttype' - Optional integer specifying the packet type:

             - ‘PACKET_HOST’ (the default) - Packet addressed to the
               local host.

             - ‘PACKET_BROADCAST’ - Physical-layer broadcast packet.

             - ‘PACKET_MULTICAST’ - Packet sent to a physical-layer
               multicast address.

             - ‘PACKET_OTHERHOST’ - Packet to some other host that has
               been caught by a device driver in promiscuous mode.

             - ‘PACKET_OUTGOING’ - Packet originating from the local
               host that is looped back to a packet socket.

        - 'hatype' - Optional integer specifying the ARP hardware
          address type.

        - 'addr' - Optional bytes-like object specifying the hardware
          physical address, whose interpretation depends on the device.

     *note Availability: 1ef7.: Linux >= 2.2.

   - *note AF_QIPCRTR: 362b. is a Linux-only socket based interface for
     communicating with services running on co-processors in Qualcomm
     platforms.  The address family is represented as a ‘(node, port)’
     tuple where the 'node' and 'port' are non-negative integers.

     *note Availability: 1ef7.: Linux >= 4.7.

     Added in version 3.8.

   - ‘IPPROTO_UDPLITE’ is a variant of UDP which allows you to specify
     what portion of a packet is covered with the checksum.  It adds two
     socket options that you can change.
     ‘self.setsockopt(IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV, length)’ will
     change what portion of outgoing packets are covered by the checksum
     and ‘self.setsockopt(IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV, length)’
     will filter out packets which cover too little of their data.  In
     both cases ‘length’ should be in ‘range(8, 2**16, 8)’.

     Such a socket should be constructed with ‘socket(AF_INET,
     SOCK_DGRAM, IPPROTO_UDPLITE)’ for IPv4 or ‘socket(AF_INET6,
     SOCK_DGRAM, IPPROTO_UDPLITE)’ for IPv6.

     *note Availability: 1ef7.: Linux >= 2.6.20, FreeBSD >= 10.1

     Added in version 3.9.

   - *note AF_HYPERV: 362c. is a Windows-only socket based interface for
     communicating with Hyper-V hosts and guests.  The address family is
     represented as a ‘(vm_id, service_id)’ tuple where the ‘vm_id’ and
     ‘service_id’ are UUID strings.

     The ‘vm_id’ is the virtual machine identifier or a set of known
     VMID values if the target is not a specific virtual machine.  Known
     VMID constants defined on ‘socket’ are:

        - ‘HV_GUID_ZERO’

        - ‘HV_GUID_BROADCAST’

        - ‘HV_GUID_WILDCARD’ - Used to bind on itself and accept
          connections from all partitions.

        - ‘HV_GUID_CHILDREN’ - Used to bind on itself and accept
          connection from child partitions.

        - ‘HV_GUID_LOOPBACK’ - Used as a target to itself.

        - ‘HV_GUID_PARENT’ - When used as a bind accepts connection from
          the parent partition.  When used as an address target it will
          connect to the parent partition.

     The ‘service_id’ is the service identifier of the registered
     service.

     Added in version 3.12.

If you use a hostname in the 'host' portion of IPv4/v6 socket address,
the program may show a nondeterministic behavior, as Python uses the
first address returned from the DNS resolution.  The socket address will
be resolved differently into an actual IPv4/v6 address, depending on the
results from DNS resolution and/or the host configuration.  For
deterministic behavior use a numeric address in 'host' portion.

All errors raise exceptions.  The normal exceptions for invalid argument
types and out-of-memory conditions can be raised.  Errors related to
socket or address semantics raise *note OSError: 41a. or one of its
subclasses.

Non-blocking mode is supported through *note setblocking(): 2d3a.  A
generalization of this based on timeouts is supported through *note
settimeout(): 362d.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0383/

   (2) https://manpages.debian.org/vsock(7)


File: python.info,  Node: Module contents<2>,  Next: Socket Objects,  Prev: Socket families,  Up: socket — Low-level networking interface

5.19.2.2 Module contents
........................

The module ‘socket’ exports the following elements.

* Menu:

* Exceptions: Exceptions<15>.
* Constants: Constants<8>.
* Functions: Functions<8>.


File: python.info,  Node: Exceptions<15>,  Next: Constants<8>,  Up: Module contents<2>

5.19.2.3 Exceptions
...................

 -- Exception: socket.error

     A deprecated alias of *note OSError: 41a.

     Changed in version 3.3: Following PEP 3151(1), this class was made
     an alias of *note OSError: 41a.

 -- Exception: socket.herror

     A subclass of *note OSError: 41a, this exception is raised for
     address-related errors, i.e.  for functions that use 'h_errno' in
     the POSIX C API, including *note gethostbyname_ex(): 1a2b. and
     *note gethostbyaddr(): 1a2a.  The accompanying value is a pair
     ‘(h_errno, string)’ representing an error returned by a library
     call.  'h_errno' is a numeric value, while 'string' represents the
     description of 'h_errno', as returned by the ‘hstrerror()’ C
     function.

     Changed in version 3.3: This class was made a subclass of *note
     OSError: 41a.

 -- Exception: socket.gaierror

     A subclass of *note OSError: 41a, this exception is raised for
     address-related errors by *note getaddrinfo(): 15ba. and *note
     getnameinfo(): 17d3.  The accompanying value is a pair ‘(error,
     string)’ representing an error returned by a library call.
     'string' represents the description of 'error', as returned by the
     ‘gai_strerror()’ C function.  The numeric 'error' value will match
     one of the ‘EAI_*’ constants defined in this module.

     Changed in version 3.3: This class was made a subclass of *note
     OSError: 41a.

 -- Exception: socket.timeout

     A deprecated alias of *note TimeoutError: 83b.

     A subclass of *note OSError: 41a, this exception is raised when a
     timeout occurs on a socket which has had timeouts enabled via a
     prior call to *note settimeout(): 362d. (or implicitly through
     *note setdefaulttimeout(): 3631.).  The accompanying value is a
     string whose value is currently always “timed out”.

     Changed in version 3.3: This class was made a subclass of *note
     OSError: 41a.

     Changed in version 3.10: This class was made an alias of *note
     TimeoutError: 83b.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3151/


File: python.info,  Node: Constants<8>,  Next: Functions<8>,  Prev: Exceptions<15>,  Up: Module contents<2>

5.19.2.4 Constants
..................

The AF_* and SOCK_* constants are now ‘AddressFamily’ and ‘SocketKind’
*note IntEnum: d06. collections.

Added in version 3.4.

 -- Data: socket.AF_UNIX
 -- Data: socket.AF_INET
 -- Data: socket.AF_INET6

     These constants represent the address (and protocol) families, used
     for the first argument to *note socket(): dcf.  If the *note
     AF_UNIX: 1955. constant is not defined then this protocol is
     unsupported.  More constants may be available depending on the
     system.

 -- Data: socket.AF_UNSPEC

     *note AF_UNSPEC: 3569. means that *note getaddrinfo(): 15ba. should
     return socket addresses for any address family (either IPv4, IPv6,
     or any other) that can be used.

 -- Data: socket.SOCK_STREAM
 -- Data: socket.SOCK_DGRAM
 -- Data: socket.SOCK_RAW
 -- Data: socket.SOCK_RDM
 -- Data: socket.SOCK_SEQPACKET

     These constants represent the socket types, used for the second
     argument to *note socket(): dcf.  More constants may be available
     depending on the system.  (Only *note SOCK_STREAM: 133c. and *note
     SOCK_DGRAM: 133b. appear to be generally useful.)

 -- Data: socket.SOCK_CLOEXEC
 -- Data: socket.SOCK_NONBLOCK

     These two constants, if defined, can be combined with the socket
     types and allow you to set some flags atomically (thus avoiding
     possible race conditions and the need for separate calls).

     See also
     ........

     Secure File Descriptor Handling(1) for a more thorough explanation.

     *note Availability: 1ef7.: Linux >= 2.6.27.

     Added in version 3.2.

 -- Data: SO_*
 -- Data: socket.SOMAXCONN

 -- Data: MSG_*

 -- Data: SOL_*

 -- Data: SCM_*

 -- Data: IPPROTO_*

 -- Data: IPPORT_*

 -- Data: INADDR_*

 -- Data: IP_*

 -- Data: IPV6_*

 -- Data: EAI_*

 -- Data: AI_*

 -- Data: NI_*

 -- Data: TCP_*

     Many constants of these forms, documented in the Unix documentation
     on sockets and/or the IP protocol, are also defined in the socket
     module.  They are generally used in arguments to the *note
     setsockopt(): cfc. and *note getsockopt(): cfb. methods of socket
     objects.  In most cases, only those symbols that are defined in the
     Unix header files are defined; for a few symbols, default values
     are provided.

     Changed in version 3.6: ‘SO_DOMAIN’, ‘SO_PROTOCOL’, ‘SO_PEERSEC’,
     ‘SO_PASSSEC’, ‘TCP_USER_TIMEOUT’, ‘TCP_CONGESTION’ were added.

     Changed in version 3.6.5: On Windows, ‘TCP_FASTOPEN’, ‘TCP_KEEPCNT’
     appear if run-time Windows supports.

     Changed in version 3.7: ‘TCP_NOTSENT_LOWAT’ was added.

     On Windows, ‘TCP_KEEPIDLE’, ‘TCP_KEEPINTVL’ appear if run-time
     Windows supports.

     Changed in version 3.10: ‘IP_RECVTOS’ was added.  Added
     ‘TCP_KEEPALIVE’.  On MacOS this constant can be used in the same
     way that ‘TCP_KEEPIDLE’ is used on Linux.

     Changed in version 3.11: Added ‘TCP_CONNECTION_INFO’.  On MacOS
     this constant can be used in the same way that ‘TCP_INFO’ is used
     on Linux and BSD.

     Changed in version 3.12: Added ‘SO_RTABLE’ and ‘SO_USER_COOKIE’.
     On OpenBSD and FreeBSD respectively those constants can be used in
     the same way that ‘SO_MARK’ is used on Linux.  Also added missing
     TCP socket options from Linux: ‘TCP_MD5SIG’,
     ‘TCP_THIN_LINEAR_TIMEOUTS’, ‘TCP_THIN_DUPACK’, ‘TCP_REPAIR’,
     ‘TCP_REPAIR_QUEUE’, ‘TCP_QUEUE_SEQ’, ‘TCP_REPAIR_OPTIONS’,
     ‘TCP_TIMESTAMP’, ‘TCP_CC_INFO’, ‘TCP_SAVE_SYN’, ‘TCP_SAVED_SYN’,
     ‘TCP_REPAIR_WINDOW’, ‘TCP_FASTOPEN_CONNECT’, ‘TCP_ULP’,
     ‘TCP_MD5SIG_EXT’, ‘TCP_FASTOPEN_KEY’, ‘TCP_FASTOPEN_NO_COOKIE’,
     ‘TCP_ZEROCOPY_RECEIVE’, ‘TCP_INQ’, ‘TCP_TX_DELAY’.  Added
     ‘IP_PKTINFO’, ‘IP_UNBLOCK_SOURCE’, ‘IP_BLOCK_SOURCE’,
     ‘IP_ADD_SOURCE_MEMBERSHIP’, ‘IP_DROP_SOURCE_MEMBERSHIP’.

     Changed in version 3.13: Added ‘SO_BINDTOIFINDEX’.  On Linux this
     constant can be used in the same way that ‘SO_BINDTODEVICE’ is
     used, but with the index of a network interface instead of its
     name.

 -- Data: socket.AF_CAN
 -- Data: socket.PF_CAN

 -- Data: SOL_CAN_*

 -- Data: CAN_*

     Many constants of these forms, documented in the Linux
     documentation, are also defined in the socket module.

     *note Availability: 1ef7.: Linux >= 2.6.25, NetBSD >= 8.

     Added in version 3.3.

     Changed in version 3.11: NetBSD support was added.

     Changed in version 3.13.4: Restored missing ‘CAN_RAW_ERR_FILTER’ on
     Linux.

 -- Data: socket.CAN_BCM

 -- Data: CAN_BCM_*

     CAN_BCM, in the CAN protocol family, is the broadcast manager (BCM)
     protocol.  Broadcast manager constants, documented in the Linux
     documentation, are also defined in the socket module.

     *note Availability: 1ef7.: Linux >= 2.6.25.

          Note: The ‘CAN_BCM_CAN_FD_FRAME’ flag is only available on
          Linux >= 4.8.

     Added in version 3.4.

 -- Data: socket.CAN_RAW_FD_FRAMES

     Enables CAN FD support in a CAN_RAW socket.  This is disabled by
     default.  This allows your application to send both CAN and CAN FD
     frames; however, you must accept both CAN and CAN FD frames when
     reading from the socket.

     This constant is documented in the Linux documentation.

     *note Availability: 1ef7.: Linux >= 3.6.

     Added in version 3.5.

 -- Data: socket.CAN_RAW_JOIN_FILTERS

     Joins the applied CAN filters such that only CAN frames that match
     all given CAN filters are passed to user space.

     This constant is documented in the Linux documentation.

     *note Availability: 1ef7.: Linux >= 4.1.

     Added in version 3.9.

 -- Data: socket.CAN_ISOTP

     CAN_ISOTP, in the CAN protocol family, is the ISO-TP (ISO 15765-2)
     protocol.  ISO-TP constants, documented in the Linux documentation.

     *note Availability: 1ef7.: Linux >= 2.6.25.

     Added in version 3.7.

 -- Data: socket.CAN_J1939

     CAN_J1939, in the CAN protocol family, is the SAE J1939 protocol.
     J1939 constants, documented in the Linux documentation.

     *note Availability: 1ef7.: Linux >= 5.4.

     Added in version 3.9.

 -- Data: socket.AF_DIVERT
 -- Data: socket.PF_DIVERT

     These two constants, documented in the FreeBSD divert(4) manual
     page, are also defined in the socket module.

     *note Availability: 1ef7.: FreeBSD >= 14.0.

     Added in version 3.12.

 -- Data: socket.AF_PACKET
 -- Data: socket.PF_PACKET

 -- Data: PACKET_*

     Many constants of these forms, documented in the Linux
     documentation, are also defined in the socket module.

     *note Availability: 1ef7.: Linux >= 2.2.

 -- Data: socket.ETH_P_ALL

     ‘ETH_P_ALL’ can be used in the *note socket: dcf. constructor as
     'proto' for the *note AF_PACKET: 362a. family in order to capture
     every packet, regardless of protocol.

     For more information, see the ‘packet(7)(2)’ manpage.

     *note Availability: 1ef7.: Linux.

     Added in version 3.12.

 -- Data: socket.AF_RDS
 -- Data: socket.PF_RDS
 -- Data: socket.SOL_RDS

 -- Data: RDS_*

     Many constants of these forms, documented in the Linux
     documentation, are also defined in the socket module.

     *note Availability: 1ef7.: Linux >= 2.6.30.

     Added in version 3.3.

 -- Data: socket.SIO_RCVALL
 -- Data: socket.SIO_KEEPALIVE_VALS
 -- Data: socket.SIO_LOOPBACK_FAST_PATH

 -- Data: RCVALL_*

     Constants for Windows’ WSAIoctl().  The constants are used as
     arguments to the *note ioctl(): cf9. method of socket objects.

     Changed in version 3.6: ‘SIO_LOOPBACK_FAST_PATH’ was added.

 -- Data: TIPC_*

     TIPC related constants, matching the ones exported by the C socket
     API. See the TIPC documentation for more information.

 -- Data: socket.AF_ALG
 -- Data: socket.SOL_ALG

 -- Data: ALG_*

     Constants for Linux Kernel cryptography.

     *note Availability: 1ef7.: Linux >= 2.6.38.

     Added in version 3.6.

 -- Data: socket.AF_VSOCK
 -- Data: socket.IOCTL_VM_SOCKETS_GET_LOCAL_CID

 -- Data: VMADDR*

 -- Data: SO_VM*

     Constants for Linux host/guest communication.

     *note Availability: 1ef7.: Linux >= 4.8.

     Added in version 3.7.

 -- Data: socket.AF_LINK

     *note Availability: 1ef7.: BSD, macOS.

     Added in version 3.4.

 -- Data: socket.has_ipv6

     This constant contains a boolean value which indicates if IPv6 is
     supported on this platform.

 -- Data: socket.BDADDR_ANY
 -- Data: socket.BDADDR_LOCAL

     These are string constants containing Bluetooth addresses with
     special meanings.  For example, *note BDADDR_ANY: 3642. can be used
     to indicate any address when specifying the binding socket with
     ‘BTPROTO_RFCOMM’.

 -- Data: socket.HCI_FILTER
 -- Data: socket.HCI_TIME_STAMP
 -- Data: socket.HCI_DATA_DIR

     For use with ‘BTPROTO_HCI’.  ‘HCI_FILTER’ is only available on
     Linux and FreeBSD. ‘HCI_TIME_STAMP’ and ‘HCI_DATA_DIR’ are only
     available on Linux.

 -- Data: socket.AF_QIPCRTR

     Constant for Qualcomm’s IPC router protocol, used to communicate
     with service providing remote processors.

     *note Availability: 1ef7.: Linux >= 4.7.

 -- Data: socket.SCM_CREDS2
 -- Data: socket.LOCAL_CREDS
 -- Data: socket.LOCAL_CREDS_PERSISTENT

     LOCAL_CREDS and LOCAL_CREDS_PERSISTENT can be used with SOCK_DGRAM,
     SOCK_STREAM sockets, equivalent to Linux/DragonFlyBSD SO_PASSCRED,
     while LOCAL_CREDS sends the credentials at first read,
     LOCAL_CREDS_PERSISTENT sends for each read, SCM_CREDS2 must be then
     used for the latter for the message type.

     Added in version 3.11.

     *note Availability: 1ef7.: FreeBSD.

 -- Data: socket.SO_INCOMING_CPU

     Constant to optimize CPU locality, to be used in conjunction with
     ‘SO_REUSEPORT’.

     Added in version 3.11.

     *note Availability: 1ef7.: Linux >= 3.9

 -- Data: socket.AF_HYPERV
 -- Data: socket.HV_PROTOCOL_RAW
 -- Data: socket.HVSOCKET_CONNECT_TIMEOUT
 -- Data: socket.HVSOCKET_CONNECT_TIMEOUT_MAX
 -- Data: socket.HVSOCKET_CONNECTED_SUSPEND
 -- Data: socket.HVSOCKET_ADDRESS_FLAG_PASSTHRU
 -- Data: socket.HV_GUID_ZERO
 -- Data: socket.HV_GUID_WILDCARD
 -- Data: socket.HV_GUID_BROADCAST
 -- Data: socket.HV_GUID_CHILDREN
 -- Data: socket.HV_GUID_LOOPBACK
 -- Data: socket.HV_GUID_PARENT

     Constants for Windows Hyper-V sockets for host/guest
     communications.

     *note Availability: 1ef7.: Windows.

     Added in version 3.12.

 -- Data: socket.ETHERTYPE_ARP
 -- Data: socket.ETHERTYPE_IP
 -- Data: socket.ETHERTYPE_IPV6
 -- Data: socket.ETHERTYPE_VLAN

     IEEE 802.3 protocol number(3).  constants.

     *note Availability: 1ef7.: Linux, FreeBSD, macOS.

     Added in version 3.12.

 -- Data: socket.SHUT_RD
 -- Data: socket.SHUT_WR
 -- Data: socket.SHUT_RDWR

     These constants are used by the *note shutdown(): 365d. method of
     socket objects.

     *note Availability: 1ef7.: not WASI.

   ---------- Footnotes ----------

   (1) https://udrepper.livejournal.com/20407.html

   (2) https://manpages.debian.org/packet(7)

   (3) 
https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.txt


File: python.info,  Node: Functions<8>,  Prev: Constants<8>,  Up: Module contents<2>

5.19.2.5 Functions
..................

* Menu:

* Creating sockets::
* Other functions: Other functions<2>.


File: python.info,  Node: Creating sockets,  Next: Other functions<2>,  Up: Functions<8>

5.19.2.6 Creating sockets
.........................

The following functions all create *note socket objects: 3660.

 -- Class: socket.socket (family=AF_INET, type=SOCK_STREAM, proto=0,
          fileno=None)

     Create a new socket using the given address family, socket type and
     protocol number.  The address family should be *note AF_INET: 1953.
     (the default), *note AF_INET6: 1954, *note AF_UNIX: 1955, *note
     AF_CAN: 3628, *note AF_PACKET: 362a, or *note AF_RDS: 363a.  The
     socket type should be *note SOCK_STREAM: 133c. (the default), *note
     SOCK_DGRAM: 133b, *note SOCK_RAW: 3633. or perhaps one of the other
     ‘SOCK_’ constants.  The protocol number is usually zero and may be
     omitted or in the case where the address family is ‘AF_CAN’ the
     protocol should be one of ‘CAN_RAW’, *note CAN_BCM: fdc, *note
     CAN_ISOTP: 3629. or *note CAN_J1939: 93c.

     If 'fileno' is specified, the values for 'family', 'type', and
     'proto' are auto-detected from the specified file descriptor.
     Auto-detection can be overruled by calling the function with
     explicit 'family', 'type', or 'proto' arguments.  This only affects
     how Python represents e.g.  the return value of *note
     socket.getpeername(): 35a8. but not the actual OS resource.  Unlike
     *note socket.fromfd(): 3661, 'fileno' will return the same socket
     and not a duplicate.  This may help close a detached socket using
     *note socket.close(): b8f.

     The newly created socket is *note non-inheritable: f30.

     Raises an *note auditing event: 1a15. ‘socket.__new__’ with
     arguments ‘self’, ‘family’, ‘type’, ‘protocol’.

     Changed in version 3.3: The AF_CAN family was added.  The AF_RDS
     family was added.

     Changed in version 3.4: The CAN_BCM protocol was added.

     Changed in version 3.4: The returned socket is now non-inheritable.

     Changed in version 3.7: The CAN_ISOTP protocol was added.

     Changed in version 3.7: When *note SOCK_NONBLOCK: c2a. or *note
     SOCK_CLOEXEC: c2b. bit flags are applied to 'type' they are
     cleared, and *note socket.type: c2c. will not reflect them.  They
     are still passed to the underlying system ‘socket()’ call.
     Therefore,

          sock = socket.socket(
              socket.AF_INET,
              socket.SOCK_STREAM | socket.SOCK_NONBLOCK)

     will still create a non-blocking socket on OSes that support
     ‘SOCK_NONBLOCK’, but ‘sock.type’ will be set to
     ‘socket.SOCK_STREAM’.

     Changed in version 3.9: The CAN_J1939 protocol was added.

     Changed in version 3.10: The IPPROTO_MPTCP protocol was added.

 -- Function: socket.socketpair ([family[, type[, proto]]])

     Build a pair of connected socket objects using the given address
     family, socket type, and protocol number.  Address family, socket
     type, and protocol number are as for the *note socket(): dcf.
     function.  The default family is *note AF_UNIX: 1955. if defined on
     the platform; otherwise, the default is *note AF_INET: 1953.

     The newly created sockets are *note non-inheritable: f30.

     Changed in version 3.2: The returned socket objects now support the
     whole socket API, rather than a subset.

     Changed in version 3.4: The returned sockets are now
     non-inheritable.

     Changed in version 3.5: Windows support added.

 -- Function: socket.create_connection (address, timeout=GLOBAL_DEFAULT,
          source_address=None, *, all_errors=False)

     Connect to a TCP service listening on the internet 'address' (a
     2-tuple ‘(host, port)’), and return the socket object.  This is a
     higher-level function than *note socket.connect(): dd1.: if 'host'
     is a non-numeric hostname, it will try to resolve it for both *note
     AF_INET: 1953. and *note AF_INET6: 1954, and then try to connect to
     all possible addresses in turn until a connection succeeds.  This
     makes it easy to write clients that are compatible to both IPv4 and
     IPv6.

     Passing the optional 'timeout' parameter will set the timeout on
     the socket instance before attempting to connect.  If no 'timeout'
     is supplied, the global default timeout setting returned by *note
     getdefaulttimeout(): 3662. is used.

     If supplied, 'source_address' must be a 2-tuple ‘(host, port)’ for
     the socket to bind to as its source address before connecting.  If
     host or port are ‘’ or 0 respectively the OS default behavior will
     be used.

     When a connection cannot be created, an exception is raised.  By
     default, it is the exception from the last address in the list.  If
     'all_errors' is ‘True’, it is an *note ExceptionGroup: 1b6.
     containing the errors of all attempts.

     Changed in version 3.2: 'source_address' was added.

     Changed in version 3.11: 'all_errors' was added.

 -- Function: socket.create_server (address, *, family=AF_INET,
          backlog=None, reuse_port=False, dualstack_ipv6=False)

     Convenience function which creates a TCP socket bound to 'address'
     (a 2-tuple ‘(host, port)’) and returns the socket object.

     'family' should be either *note AF_INET: 1953. or *note AF_INET6:
     1954.  'backlog' is the queue size passed to *note socket.listen():
     e92.; if not specified , a default reasonable value is chosen.
     'reuse_port' dictates whether to set the ‘SO_REUSEPORT’ socket
     option.

     If 'dualstack_ipv6' is true, 'family' is *note AF_INET6: 1954. and
     the platform supports it the socket will be able to accept both
     IPv4 and IPv6 connections, else it will raise *note ValueError:
     202.  Most POSIX platforms and Windows are supposed to support this
     functionality.  When this functionality is enabled the address
     returned by *note socket.getpeername(): 35a8. when an IPv4
     connection occurs will be an IPv6 address represented as an
     IPv4-mapped IPv6 address.  If 'dualstack_ipv6' is false it will
     explicitly disable this functionality on platforms that enable it
     by default (e.g.  Linux).  This parameter can be used in
     conjunction with *note has_dualstack_ipv6(): a39.:

          import socket

          addr = ("", 8080)  # all interfaces, port 8080
          if socket.has_dualstack_ipv6():
              s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
          else:
              s = socket.create_server(addr)

          Note: On POSIX platforms the ‘SO_REUSEADDR’ socket option is
          set in order to immediately reuse previous sockets which were
          bound on the same 'address' and remained in TIME_WAIT state.

     Added in version 3.8.

 -- Function: socket.has_dualstack_ipv6 ()

     Return ‘True’ if the platform supports creating a TCP socket which
     can handle both IPv4 and IPv6 connections.

     Added in version 3.8.

 -- Function: socket.fromfd (fd, family, type, proto=0)

     Duplicate the file descriptor 'fd' (an integer as returned by a
     file object’s *note fileno(): 15f5. method) and build a socket
     object from the result.  Address family, socket type and protocol
     number are as for the *note socket(): dcf. function.  The file
     descriptor should refer to a socket, but this is not checked —
     subsequent operations on the object may fail if the file descriptor
     is invalid.  This function is rarely needed, but can be used to get
     or set socket options on a socket passed to a program as standard
     input or output (such as a server started by the Unix inet daemon).
     The socket is assumed to be in blocking mode.

     The newly created socket is *note non-inheritable: f30.

     Changed in version 3.4: The returned socket is now non-inheritable.

 -- Function: socket.fromshare (data)

     Instantiate a socket from data obtained from the *note
     socket.share(): c28. method.  The socket is assumed to be in
     blocking mode.

     *note Availability: 1ef7.: Windows.

     Added in version 3.3.

 -- Data: socket.SocketType

     This is a Python type object that represents the socket object
     type.  It is the same as ‘type(socket(...))’.


File: python.info,  Node: Other functions<2>,  Prev: Creating sockets,  Up: Functions<8>

5.19.2.7 Other functions
........................

The ‘socket’ module also offers various network-related services:

 -- Function: socket.close (fd)

     Close a socket file descriptor.  This is like *note os.close():
     b90, but for sockets.  On some platforms (most notably Windows)
     ‘os.close()’ does not work for socket file descriptors.

     Added in version 3.7.

 -- Function: socket.getaddrinfo (host, port, family=AF_UNSPEC, type=0,
          proto=0, flags=0)

     This function wraps the C function ‘getaddrinfo’ of the underlying
     system.

     Translate the 'host'/'port' argument into a sequence of 5-tuples
     that contain all the necessary arguments for creating a socket
     connected to that service.  'host' is a domain name, a string
     representation of an IPv4/v6 address or ‘None’.  'port' is a string
     service name such as ‘'http'’, a numeric port number or ‘None’.  By
     passing ‘None’ as the value of 'host' and 'port', you can pass
     ‘NULL’ to the underlying C API.

     The 'family', 'type' and 'proto' arguments can be optionally
     specified in order to provide options and limit the list of
     addresses returned.  Pass their default values (*note AF_UNSPEC:
     3569, 0, and 0, respectively) to not limit the results.  See the
     note below for details.

     The 'flags' argument can be one or several of the ‘AI_*’ constants,
     and will influence how results are computed and returned.  For
     example, ‘AI_NUMERICHOST’ will disable domain name resolution and
     will raise an error if 'host' is a domain name.

     The function returns a list of 5-tuples with the following
     structure:

     ‘(family, type, proto, canonname, sockaddr)’

     In these tuples, 'family', 'type', 'proto' are all integers and are
     meant to be passed to the *note socket(): dcf. function.
     'canonname' will be a string representing the canonical name of the
     'host' if ‘AI_CANONNAME’ is part of the 'flags' argument; else
     'canonname' will be empty.  'sockaddr' is a tuple describing a
     socket address, whose format depends on the returned 'family' (a
     ‘(address, port)’ 2-tuple for *note AF_INET: 1953, a ‘(address,
     port, flowinfo, scope_id)’ 4-tuple for *note AF_INET6: 1954.), and
     is meant to be passed to the *note socket.connect(): dd1. method.

          Note: If you intend to use results from ‘getaddrinfo()’ to
          create a socket (rather than, for example, retrieve
          'canonname'), consider limiting the results by 'type' (e.g.
          *note SOCK_STREAM: 133c. or *note SOCK_DGRAM: 133b.) and/or
          'proto' (e.g.  ‘IPPROTO_TCP’ or ‘IPPROTO_UDP’) that your
          application can handle.

          The behavior with default values of 'family', 'type', 'proto'
          and 'flags' is system-specific.

          Many systems (for example, most Linux configurations) will
          return a sorted list of all matching addresses.  These
          addresses should generally be tried in order until a
          connection succeeds (possibly tried in parallel, for example,
          using a Happy Eyeballs(1) algorithm).  In these cases,
          limiting the 'type' and/or 'proto' can help eliminate
          unsuccessful or unusable connection attempts.

          Some systems will, however, only return a single address.
          (For example, this was reported on Solaris and AIX
          configurations.)  On these systems, limiting the 'type' and/or
          'proto' helps ensure that this address is usable.

     Raises an *note auditing event: 1a15. ‘socket.getaddrinfo’ with
     arguments ‘host’, ‘port’, ‘family’, ‘type’, ‘protocol’.

     The following example fetches address information for a
     hypothetical TCP connection to ‘example.org’ on port 80 (results
     may differ on your system if IPv6 isn’t enabled):

          >>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
          [(socket.AF_INET6, socket.SOCK_STREAM,
           6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
           (socket.AF_INET, socket.SOCK_STREAM,
           6, '', ('93.184.216.34', 80))]

     Changed in version 3.2: parameters can now be passed using keyword
     arguments.

     Changed in version 3.7: for IPv6 multicast addresses, string
     representing an address will not contain ‘%scope_id’ part.

 -- Function: socket.getfqdn ([name])

     Return a fully qualified domain name for 'name'.  If 'name' is
     omitted or empty, it is interpreted as the local host.  To find the
     fully qualified name, the hostname returned by *note
     gethostbyaddr(): 1a2a. is checked, followed by aliases for the
     host, if available.  The first name which includes a period is
     selected.  In case no fully qualified domain name is available and
     'name' was provided, it is returned unchanged.  If 'name' was empty
     or equal to ‘'0.0.0.0'’, the hostname from *note gethostname():
     2d23. is returned.

 -- Function: socket.gethostbyname (hostname)

     Translate a host name to IPv4 address format.  The IPv4 address is
     returned as a string, such as ‘'100.50.200.5'’.  If the host name
     is an IPv4 address itself it is returned unchanged.  See *note
     gethostbyname_ex(): 1a2b. for a more complete interface.
     ‘gethostbyname()’ does not support IPv6 name resolution, and *note
     getaddrinfo(): 15ba. should be used instead for IPv4/v6 dual stack
     support.

     Raises an *note auditing event: 1a15. ‘socket.gethostbyname’ with
     argument ‘hostname’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.gethostbyname_ex (hostname)

     Translate a host name to IPv4 address format, extended interface.
     Return a 3-tuple ‘(hostname, aliaslist, ipaddrlist)’ where
     'hostname' is the host’s primary host name, 'aliaslist' is a
     (possibly empty) list of alternative host names for the same
     address, and 'ipaddrlist' is a list of IPv4 addresses for the same
     interface on the same host (often but not always a single address).
     ‘gethostbyname_ex()’ does not support IPv6 name resolution, and
     *note getaddrinfo(): 15ba. should be used instead for IPv4/v6 dual
     stack support.

     Raises an *note auditing event: 1a15. ‘socket.gethostbyname’ with
     argument ‘hostname’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.gethostname ()

     Return a string containing the hostname of the machine where the
     Python interpreter is currently executing.

     Raises an *note auditing event: 1a15. ‘socket.gethostname’ with no
     arguments.

     Note: ‘gethostname()’ doesn’t always return the fully qualified
     domain name; use *note getfqdn(): 1890. for that.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.gethostbyaddr (ip_address)

     Return a 3-tuple ‘(hostname, aliaslist, ipaddrlist)’ where
     'hostname' is the primary host name responding to the given
     'ip_address', 'aliaslist' is a (possibly empty) list of alternative
     host names for the same address, and 'ipaddrlist' is a list of
     IPv4/v6 addresses for the same interface on the same host (most
     likely containing only a single address).  To find the fully
     qualified domain name, use the function *note getfqdn(): 1890.
     ‘gethostbyaddr()’ supports both IPv4 and IPv6.

     Raises an *note auditing event: 1a15. ‘socket.gethostbyaddr’ with
     argument ‘ip_address’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.getnameinfo (sockaddr, flags)

     Translate a socket address 'sockaddr' into a 2-tuple ‘(host,
     port)’.  Depending on the settings of 'flags', the result can
     contain a fully qualified domain name or numeric address
     representation in 'host'.  Similarly, 'port' can contain a string
     port name or a numeric port number.

     For IPv6 addresses, ‘%scope_id’ is appended to the host part if
     'sockaddr' contains meaningful 'scope_id'.  Usually this happens
     for multicast addresses.

     For more information about 'flags' you can consult
     ‘getnameinfo(3)(2)’.

     Raises an *note auditing event: 1a15. ‘socket.getnameinfo’ with
     argument ‘sockaddr’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.getprotobyname (protocolname)

     Translate an internet protocol name (for example, ‘'icmp'’) to a
     constant suitable for passing as the (optional) third argument to
     the *note socket(): dcf. function.  This is usually only needed for
     sockets opened in “raw” mode (*note SOCK_RAW: 3633.); for the
     normal socket modes, the correct protocol is chosen automatically
     if the protocol is omitted or zero.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.getservbyname (servicename[, protocolname])

     Translate an internet service name and protocol name to a port
     number for that service.  The optional protocol name, if given,
     should be ‘'tcp'’ or ‘'udp'’, otherwise any protocol will match.

     Raises an *note auditing event: 1a15. ‘socket.getservbyname’ with
     arguments ‘servicename’, ‘protocolname’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.getservbyport (port[, protocolname])

     Translate an internet port number and protocol name to a service
     name for that service.  The optional protocol name, if given,
     should be ‘'tcp'’ or ‘'udp'’, otherwise any protocol will match.

     Raises an *note auditing event: 1a15. ‘socket.getservbyport’ with
     arguments ‘port’, ‘protocolname’.

     *note Availability: 1ef7.: not WASI.

 -- Function: socket.ntohl (x)

     Convert 32-bit positive integers from network to host byte order.
     On machines where the host byte order is the same as network byte
     order, this is a no-op; otherwise, it performs a 4-byte swap
     operation.

 -- Function: socket.ntohs (x)

     Convert 16-bit positive integers from network to host byte order.
     On machines where the host byte order is the same as network byte
     order, this is a no-op; otherwise, it performs a 2-byte swap
     operation.

     Changed in version 3.10: Raises *note OverflowError: 888. if 'x'
     does not fit in a 16-bit unsigned integer.

 -- Function: socket.htonl (x)

     Convert 32-bit positive integers from host to network byte order.
     On machines where the host byte order is the same as network byte
     order, this is a no-op; otherwise, it performs a 4-byte swap
     operation.

 -- Function: socket.htons (x)

     Convert 16-bit positive integers from host to network byte order.
     On machines where the host byte order is the same as network byte
     order, this is a no-op; otherwise, it performs a 2-byte swap
     operation.

     Changed in version 3.10: Raises *note OverflowError: 888. if 'x'
     does not fit in a 16-bit unsigned integer.

 -- Function: socket.inet_aton (ip_string)

     Convert an IPv4 address from dotted-quad string format (for
     example, ‘123.45.67.89’) to 32-bit packed binary format, as a bytes
     object four characters in length.  This is useful when conversing
     with a program that uses the standard C library and needs objects
     of type ‘in_addr’, which is the C type for the 32-bit packed binary
     this function returns.

     ‘inet_aton()’ also accepts strings with less than three dots; see
     the Unix manual page ‘inet(3)(3)’ for details.

     If the IPv4 address string passed to this function is invalid,
     *note OSError: 41a. will be raised.  Note that exactly what is
     valid depends on the underlying C implementation of ‘inet_aton()’.

     ‘inet_aton()’ does not support IPv6, and *note inet_pton(): 96c.
     should be used instead for IPv4/v6 dual stack support.

 -- Function: socket.inet_ntoa (packed_ip)

     Convert a 32-bit packed IPv4 address (a *note bytes-like object:
     d55. four bytes in length) to its standard dotted-quad string
     representation (for example, ‘123.45.67.89’).  This is useful when
     conversing with a program that uses the standard C library and
     needs objects of type ‘in_addr’, which is the C type for the 32-bit
     packed binary data this function takes as an argument.

     If the byte sequence passed to this function is not exactly 4 bytes
     in length, *note OSError: 41a. will be raised.  ‘inet_ntoa()’ does
     not support IPv6, and *note inet_ntop(): fde. should be used
     instead for IPv4/v6 dual stack support.

     Changed in version 3.5: Writable *note bytes-like object: d55. is
     now accepted.

 -- Function: socket.inet_pton (address_family, ip_string)

     Convert an IP address from its family-specific string format to a
     packed, binary format.  ‘inet_pton()’ is useful when a library or
     network protocol calls for an object of type ‘in_addr’ (similar to
     *note inet_aton(): 96b.) or ‘in6_addr’.

     Supported values for 'address_family' are currently *note AF_INET:
     1953. and *note AF_INET6: 1954.  If the IP address string
     'ip_string' is invalid, *note OSError: 41a. will be raised.  Note
     that exactly what is valid depends on both the value of
     'address_family' and the underlying implementation of
     ‘inet_pton()’.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.4: Windows support added

 -- Function: socket.inet_ntop (address_family, packed_ip)

     Convert a packed IP address (a *note bytes-like object: d55. of
     some number of bytes) to its standard, family-specific string
     representation (for example, ‘'7.10.0.5'’ or ‘'5aef:2b::8'’).
     ‘inet_ntop()’ is useful when a library or network protocol returns
     an object of type ‘in_addr’ (similar to *note inet_ntoa(): 366b.)
     or ‘in6_addr’.

     Supported values for 'address_family' are currently *note AF_INET:
     1953. and *note AF_INET6: 1954.  If the bytes object 'packed_ip' is
     not the correct length for the specified address family, *note
     ValueError: 202. will be raised.  *note OSError: 41a. is raised for
     errors from the call to ‘inet_ntop()’.

     *note Availability: 1ef7.: Unix, Windows.

     Changed in version 3.4: Windows support added

     Changed in version 3.5: Writable *note bytes-like object: d55. is
     now accepted.

 -- Function: socket.CMSG_LEN (length)

     Return the total length, without trailing padding, of an ancillary
     data item with associated data of the given 'length'.  This value
     can often be used as the buffer size for *note recvmsg(): dd4. to
     receive a single item of ancillary data, but RFC 3542(4) requires
     portable applications to use *note CMSG_SPACE(): 1bc6. and thus
     include space for padding, even when the item will be the last in
     the buffer.  Raises *note OverflowError: 888. if 'length' is
     outside the permissible range of values.

     *note Availability: 1ef7.: Unix, not WASI.

     Most Unix platforms.

     Added in version 3.3.

 -- Function: socket.CMSG_SPACE (length)

     Return the buffer size needed for *note recvmsg(): dd4. to receive
     an ancillary data item with associated data of the given 'length',
     along with any trailing padding.  The buffer space needed to
     receive multiple items is the sum of the ‘CMSG_SPACE()’ values for
     their associated data lengths.  Raises *note OverflowError: 888. if
     'length' is outside the permissible range of values.

     Note that some systems might support ancillary data without
     providing this function.  Also note that setting the buffer size
     using the results of this function may not precisely limit the
     amount of ancillary data that can be received, since additional
     data may be able to fit into the padding area.

     *note Availability: 1ef7.: Unix, not WASI.

     most Unix platforms.

     Added in version 3.3.

 -- Function: socket.getdefaulttimeout ()

     Return the default timeout in seconds (float) for new socket
     objects.  A value of ‘None’ indicates that new socket objects have
     no timeout.  When the socket module is first imported, the default
     is ‘None’.

 -- Function: socket.setdefaulttimeout (timeout)

     Set the default timeout in seconds (float) for new socket objects.
     When the socket module is first imported, the default is ‘None’.
     See *note settimeout(): 362d. for possible values and their
     respective meanings.

 -- Function: socket.sethostname (name)

     Set the machine’s hostname to 'name'.  This will raise an *note
     OSError: 41a. if you don’t have enough rights.

     Raises an *note auditing event: 1a15. ‘socket.sethostname’ with
     argument ‘name’.

     *note Availability: 1ef7.: Unix, not Android.

     Added in version 3.3.

 -- Function: socket.if_nameindex ()

     Return a list of network interface information (index int, name
     string) tuples.  *note OSError: 41a. if the system call fails.

     *note Availability: 1ef7.: Unix, Windows, not WASI.

     Added in version 3.3.

     Changed in version 3.8: Windows support was added.

          Note: On Windows network interfaces have different names in
          different contexts (all names are examples):

             * UUID: ‘{FB605B73-AAC2-49A6-9A2F-25416AEA0573}’

             * name: ‘ethernet_32770’

             * friendly name: ‘vEthernet (nat)’

             * description: ‘Hyper-V Virtual Ethernet Adapter’

          This function returns names of the second form from the list,
          ‘ethernet_32770’ in this example case.

 -- Function: socket.if_nametoindex (if_name)

     Return a network interface index number corresponding to an
     interface name.  *note OSError: 41a. if no interface with the given
     name exists.

     *note Availability: 1ef7.: Unix, Windows, not WASI.

     Added in version 3.3.

     Changed in version 3.8: Windows support was added.

     See also
     ........

     “Interface name” is a name as documented in *note if_nameindex():
     a3a.

 -- Function: socket.if_indextoname (if_index)

     Return a network interface name corresponding to an interface index
     number.  *note OSError: 41a. if no interface with the given index
     exists.

     *note Availability: 1ef7.: Unix, Windows, not WASI.

     Added in version 3.3.

     Changed in version 3.8: Windows support was added.

     See also
     ........

     “Interface name” is a name as documented in *note if_nameindex():
     a3a.

 -- Function: socket.send_fds (sock, buffers, fds[, flags[, address]])

     Send the list of file descriptors 'fds' over an *note AF_UNIX:
     1955. socket 'sock'.  The 'fds' parameter is a sequence of file
     descriptors.  Consult *note sendmsg(): 479. for the documentation
     of these parameters.

     *note Availability: 1ef7.: Unix, not WASI.

     Unix platforms supporting *note sendmsg(): 479. and ‘SCM_RIGHTS’
     mechanism.

     Added in version 3.9.

 -- Function: socket.recv_fds (sock, bufsize, maxfds[, flags])

     Receive up to 'maxfds' file descriptors from an *note AF_UNIX:
     1955. socket 'sock'.  Return ‘(msg, list(fds), flags, addr)’.
     Consult *note recvmsg(): dd4. for the documentation of these
     parameters.

     *note Availability: 1ef7.: Unix, not WASI.

     Unix platforms supporting *note recvmsg(): dd4. and ‘SCM_RIGHTS’
     mechanism.

     Added in version 3.9.

          Note: Any truncated integers at the end of the list of file
          descriptors.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Happy_Eyeballs

   (2) https://manpages.debian.org/getnameinfo(3)

   (3) https://manpages.debian.org/inet(3)

   (4) https://datatracker.ietf.org/doc/html/rfc3542.html


File: python.info,  Node: Socket Objects,  Next: Notes on socket timeouts,  Prev: Module contents<2>,  Up: socket — Low-level networking interface

5.19.2.8 Socket Objects
.......................

Socket objects have the following methods.  Except for *note makefile():
11e3, these correspond to Unix system calls applicable to sockets.

Changed in version 3.2: Support for the *note context manager: 5d7.
protocol was added.  Exiting the context manager is equivalent to
calling *note close(): b8f.

 -- Method: socket.accept ()

     Accept a connection.  The socket must be bound to an address and
     listening for connections.  The return value is a pair ‘(conn,
     address)’ where 'conn' is a 'new' socket object usable to send and
     receive data on the connection, and 'address' is the address bound
     to the socket on the other end of the connection.

     The newly created socket is *note non-inheritable: f30.

     Changed in version 3.4: The socket is now non-inheritable.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(1) for the rationale).

 -- Method: socket.bind (address)

     Bind the socket to 'address'.  The socket must not already be
     bound.  The format of 'address' depends on the address family — see
     *note Socket families: 3625.

     Raises an *note auditing event: 1a15. ‘socket.bind’ with arguments
     ‘self’, ‘address’.

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.close ()

     Mark the socket closed.  The underlying system resource (e.g.  a
     file descriptor) is also closed when all file objects from *note
     makefile(): 11e3. are closed.  Once that happens, all future
     operations on the socket object will fail.  The remote end will
     receive no more data (after queued data is flushed).

     Sockets are automatically closed when they are garbage-collected,
     but it is recommended to ‘close()’ them explicitly, or to use a
     *note with: 5d5. statement around them.

     Changed in version 3.6: *note OSError: 41a. is now raised if an
     error occurs when the underlying ‘close()’ call is made.

          Note: ‘close()’ releases the resource associated with a
          connection but does not necessarily close the connection
          immediately.  If you want to close the connection in a timely
          fashion, call *note shutdown(): 365d. before ‘close()’.

 -- Method: socket.connect (address)

     Connect to a remote socket at 'address'.  The format of 'address'
     depends on the address family — see *note Socket families: 3625.

     If the connection is interrupted by a signal, the method waits
     until the connection completes, or raises a *note TimeoutError:
     83b. on timeout, if the signal handler doesn’t raise an exception
     and the socket is blocking or has a timeout.  For non-blocking
     sockets, the method raises an *note InterruptedError: db6.
     exception if the connection is interrupted by a signal (or the
     exception raised by the signal handler).

     Raises an *note auditing event: 1a15. ‘socket.connect’ with
     arguments ‘self’, ‘address’.

     Changed in version 3.5: The method now waits until the connection
     completes instead of raising an *note InterruptedError: db6.
     exception if the connection is interrupted by a signal, the signal
     handler doesn’t raise an exception and the socket is blocking or
     has a timeout (see the PEP 475(2) for the rationale).

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.connect_ex (address)

     Like ‘connect(address)’, but return an error indicator instead of
     raising an exception for errors returned by the C-level ‘connect()’
     call (other problems, such as “host not found,” can still raise
     exceptions).  The error indicator is ‘0’ if the operation
     succeeded, otherwise the value of the ‘errno’ variable.  This is
     useful to support, for example, asynchronous connects.

     Raises an *note auditing event: 1a15. ‘socket.connect’ with
     arguments ‘self’, ‘address’.

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.detach ()

     Put the socket object into closed state without actually closing
     the underlying file descriptor.  The file descriptor is returned,
     and can be reused for other purposes.

     Added in version 3.2.

 -- Method: socket.dup ()

     Duplicate the socket.

     The newly created socket is *note non-inheritable: f30.

     Changed in version 3.4: The socket is now non-inheritable.

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.fileno ()

     Return the socket’s file descriptor (a small integer), or -1 on
     failure.  This is useful with *note select.select(): dce.

     Under Windows the small integer returned by this method cannot be
     used where a file descriptor can be used (such as *note
     os.fdopen(): 20e3.).  Unix does not have this limitation.

 -- Method: socket.get_inheritable ()

     Get the *note inheritable flag: f30. of the socket’s file
     descriptor or socket’s handle: ‘True’ if the socket can be
     inherited in child processes, ‘False’ if it cannot.

     Added in version 3.4.

 -- Method: socket.getpeername ()

     Return the remote address to which the socket is connected.  This
     is useful to find out the port number of a remote IPv4/v6 socket,
     for instance.  The format of the address returned depends on the
     address family — see *note Socket families: 3625.  On some systems
     this function is not supported.

 -- Method: socket.getsockname ()

     Return the socket’s own address.  This is useful to find out the
     port number of an IPv4/v6 socket, for instance.  The format of the
     address returned depends on the address family — see *note Socket
     families: 3625.

 -- Method: socket.getsockopt (level, optname[, buflen])

     Return the value of the given socket option (see the Unix man page
     ‘getsockopt(2)(3)’).  The needed symbolic constants (*note SO_*
     etc.: b91.) are defined in this module.  If 'buflen' is absent, an
     integer option is assumed and its integer value is returned by the
     function.  If 'buflen' is present, it specifies the maximum length
     of the buffer used to receive the option in, and this buffer is
     returned as a bytes object.  It is up to the caller to decode the
     contents of the buffer (see the optional built-in module *note
     struct: d5. for a way to decode C structures encoded as byte
     strings).

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.getblocking ()

     Return ‘True’ if socket is in blocking mode, ‘False’ if in
     non-blocking.

     This is equivalent to checking ‘socket.gettimeout() != 0’.

     Added in version 3.7.

 -- Method: socket.gettimeout ()

     Return the timeout in seconds (float) associated with socket
     operations, or ‘None’ if no timeout is set.  This reflects the last
     call to *note setblocking(): 2d3a. or *note settimeout(): 362d.

 -- Method: socket.ioctl (control, option)


     Platform: Windows

     The ‘ioctl()’ method is a limited interface to the WSAIoctl system
     interface.  Please refer to the Win32 documentation(4) for more
     information.

     On other platforms, the generic *note fcntl.fcntl(): 3670. and
     *note fcntl.ioctl(): 14ca. functions may be used; they accept a
     socket object as their first argument.

     Currently only the following control codes are supported:
     ‘SIO_RCVALL’, ‘SIO_KEEPALIVE_VALS’, and ‘SIO_LOOPBACK_FAST_PATH’.

     Changed in version 3.6: ‘SIO_LOOPBACK_FAST_PATH’ was added.

 -- Method: socket.listen ([backlog])

     Enable a server to accept connections.  If 'backlog' is specified,
     it must be at least 0 (if it is lower, it is set to 0); it
     specifies the number of unaccepted connections that the system will
     allow before refusing new connections.  If not specified, a default
     reasonable value is chosen.

     *note Availability: 1ef7.: not WASI.

     Changed in version 3.5: The 'backlog' parameter is now optional.

 -- Method: socket.makefile (mode='r', buffering=None, *, encoding=None,
          errors=None, newline=None)

     Return a *note file object: 1208. associated with the socket.  The
     exact returned type depends on the arguments given to ‘makefile()’.
     These arguments are interpreted the same way as by the built-in
     *note open(): 51f. function, except the only supported 'mode'
     values are ‘'r'’ (default), ‘'w'’, ‘'b'’, or a combination of
     those.

     The socket must be in blocking mode; it can have a timeout, but the
     file object’s internal buffer may end up in an inconsistent state
     if a timeout occurs.

     Closing the file object returned by ‘makefile()’ won’t close the
     original socket unless all other file objects have been closed and
     *note socket.close(): b8f. has been called on the socket object.

          Note: On Windows, the file-like object created by ‘makefile()’
          cannot be used where a file object with a file descriptor is
          expected, such as the stream arguments of *note
          subprocess.Popen(): 199.

 -- Method: socket.recv (bufsize[, flags])

     Receive data from the socket.  The return value is a bytes object
     representing the data received.  The maximum amount of data to be
     received at once is specified by 'bufsize'.  A returned empty bytes
     object indicates that the client has disconnected.  See the Unix
     manual page ‘recv(2)(5)’ for the meaning of the optional argument
     'flags'; it defaults to zero.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(6) for the rationale).

 -- Method: socket.recvfrom (bufsize[, flags])

     Receive data from the socket.  The return value is a pair ‘(bytes,
     address)’ where 'bytes' is a bytes object representing the data
     received and 'address' is the address of the socket sending the
     data.  See the Unix manual page ‘recv(2)(7)’ for the meaning of the
     optional argument 'flags'; it defaults to zero.  The format of
     'address' depends on the address family — see *note Socket
     families: 3625.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(8) for the rationale).

     Changed in version 3.7: For multicast IPv6 address, first item of
     'address' does not contain ‘%scope_id’ part anymore.  In order to
     get full IPv6 address use *note getnameinfo(): 17d3.

 -- Method: socket.recvmsg (bufsize[, ancbufsize[, flags]])

     Receive normal data (up to 'bufsize' bytes) and ancillary data from
     the socket.  The 'ancbufsize' argument sets the size in bytes of
     the internal buffer used to receive the ancillary data; it defaults
     to 0, meaning that no ancillary data will be received.  Appropriate
     buffer sizes for ancillary data can be calculated using *note
     CMSG_SPACE(): 1bc6. or *note CMSG_LEN(): 1bc7, and items which do
     not fit into the buffer might be truncated or discarded.  The
     'flags' argument defaults to 0 and has the same meaning as for
     *note recv(): dd2.

     The return value is a 4-tuple: ‘(data, ancdata, msg_flags,
     address)’.  The 'data' item is a *note bytes: 1c2. object holding
     the non-ancillary data received.  The 'ancdata' item is a list of
     zero or more tuples ‘(cmsg_level, cmsg_type, cmsg_data)’
     representing the ancillary data (control messages) received:
     'cmsg_level' and 'cmsg_type' are integers specifying the protocol
     level and protocol-specific type respectively, and 'cmsg_data' is a
     ‘bytes’ object holding the associated data.  The 'msg_flags' item
     is the bitwise OR of various flags indicating conditions on the
     received message; see your system documentation for details.  If
     the receiving socket is unconnected, 'address' is the address of
     the sending socket, if available; otherwise, its value is
     unspecified.

     On some systems, *note sendmsg(): 479. and ‘recvmsg()’ can be used
     to pass file descriptors between processes over an *note AF_UNIX:
     1955. socket.  When this facility is used (it is often restricted
     to *note SOCK_STREAM: 133c. sockets), ‘recvmsg()’ will return, in
     its ancillary data, items of the form ‘(socket.SOL_SOCKET,
     socket.SCM_RIGHTS, fds)’, where 'fds' is a *note bytes: 1c2. object
     representing the new file descriptors as a binary array of the
     native C int type.  If ‘recvmsg()’ raises an exception after the
     system call returns, it will first attempt to close any file
     descriptors received via this mechanism.

     Some systems do not indicate the truncated length of ancillary data
     items which have been only partially received.  If an item appears
     to extend beyond the end of the buffer, ‘recvmsg()’ will issue a
     *note RuntimeWarning: 1bd, and will return the part of it which is
     inside the buffer provided it has not been truncated before the
     start of its associated data.

     On systems which support the ‘SCM_RIGHTS’ mechanism, the following
     function will receive up to 'maxfds' file descriptors, returning
     the message data and a list containing the descriptors (while
     ignoring unexpected conditions such as unrelated control messages
     being received).  See also *note sendmsg(): 479.

          import socket, array

          def recv_fds(sock, msglen, maxfds):
              fds = array.array("i")   # Array of ints
              msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
              for cmsg_level, cmsg_type, cmsg_data in ancdata:
                  if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                      # Append data, ignoring any truncated integers at the end.
                      fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
              return msg, list(fds)

     *note Availability: 1ef7.: Unix.

     Most Unix platforms.

     Added in version 3.3.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(9) for the rationale).

 -- Method: socket.recvmsg_into (buffers[, ancbufsize[, flags]])

     Receive normal data and ancillary data from the socket, behaving as
     *note recvmsg(): dd4. would, but scatter the non-ancillary data
     into a series of buffers instead of returning a new bytes object.
     The 'buffers' argument must be an iterable of objects that export
     writable buffers (e.g.  *note bytearray: 2ea. objects); these will
     be filled with successive chunks of the non-ancillary data until it
     has all been written or there are no more buffers.  The operating
     system may set a limit (*note sysconf(): 1670. value ‘SC_IOV_MAX’)
     on the number of buffers that can be used.  The 'ancbufsize' and
     'flags' arguments have the same meaning as for ‘recvmsg()’.

     The return value is a 4-tuple: ‘(nbytes, ancdata, msg_flags,
     address)’, where 'nbytes' is the total number of bytes of
     non-ancillary data written into the buffers, and 'ancdata',
     'msg_flags' and 'address' are the same as for *note recvmsg(): dd4.

     Example:

          >>> import socket
          >>> s1, s2 = socket.socketpair()
          >>> b1 = bytearray(b'----')
          >>> b2 = bytearray(b'0123456789')
          >>> b3 = bytearray(b'--------------')
          >>> s1.send(b'Mary had a little lamb')
          22
          >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
          (22, [], 0, None)
          >>> [b1, b2, b3]
          [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]

     *note Availability: 1ef7.: Unix.

     Most Unix platforms.

     Added in version 3.3.

 -- Method: socket.recvfrom_into (buffer[, nbytes[, flags]])

     Receive data from the socket, writing it into 'buffer' instead of
     creating a new bytestring.  The return value is a pair ‘(nbytes,
     address)’ where 'nbytes' is the number of bytes received and
     'address' is the address of the socket sending the data.  See the
     Unix manual page ‘recv(2)(10)’ for the meaning of the optional
     argument 'flags'; it defaults to zero.  The format of 'address'
     depends on the address family — see *note Socket families: 3625.

 -- Method: socket.recv_into (buffer[, nbytes[, flags]])

     Receive up to 'nbytes' bytes from the socket, storing the data into
     a buffer rather than creating a new bytestring.  If 'nbytes' is not
     specified (or 0), receive up to the size available in the given
     buffer.  Returns the number of bytes received.  See the Unix manual
     page ‘recv(2)(11)’ for the meaning of the optional argument
     'flags'; it defaults to zero.

 -- Method: socket.send (bytes[, flags])

     Send data to the socket.  The socket must be connected to a remote
     socket.  The optional 'flags' argument has the same meaning as for
     *note recv(): dd2.  Returns the number of bytes sent.  Applications
     are responsible for checking that all data has been sent; if only
     some of the data was transmitted, the application needs to attempt
     delivery of the remaining data.  For further information on this
     topic, consult the *note Socket Programming HOWTO: 3671.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(12) for the rationale).

 -- Method: socket.sendall (bytes[, flags])

     Send data to the socket.  The socket must be connected to a remote
     socket.  The optional 'flags' argument has the same meaning as for
     *note recv(): dd2.  Unlike *note send(): dd5, this method continues
     to send data from 'bytes' until either all data has been sent or an
     error occurs.  ‘None’ is returned on success.  On error, an
     exception is raised, and there is no way to determine how much
     data, if any, was successfully sent.

     Changed in version 3.5: The socket timeout is no longer reset each
     time data is sent successfully.  The socket timeout is now the
     maximum total duration to send all data.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(13) for the rationale).

 -- Method: socket.sendto (bytes, address)

 -- Method: socket.sendto (bytes, flags, address)

     Send data to the socket.  The socket should not be connected to a
     remote socket, since the destination socket is specified by
     'address'.  The optional 'flags' argument has the same meaning as
     for *note recv(): dd2.  Return the number of bytes sent.  The
     format of 'address' depends on the address family — see *note
     Socket families: 3625.

     Raises an *note auditing event: 1a15. ‘socket.sendto’ with
     arguments ‘self’, ‘address’.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(14) for the rationale).

 -- Method: socket.sendmsg (buffers[, ancdata[, flags[, address]]])

     Send normal and ancillary data to the socket, gathering the
     non-ancillary data from a series of buffers and concatenating it
     into a single message.  The 'buffers' argument specifies the
     non-ancillary data as an iterable of *note bytes-like objects: d55.
     (e.g.  *note bytes: 1c2. objects); the operating system may set a
     limit (*note sysconf(): 1670. value ‘SC_IOV_MAX’) on the number of
     buffers that can be used.  The 'ancdata' argument specifies the
     ancillary data (control messages) as an iterable of zero or more
     tuples ‘(cmsg_level, cmsg_type, cmsg_data)’, where 'cmsg_level' and
     'cmsg_type' are integers specifying the protocol level and
     protocol-specific type respectively, and 'cmsg_data' is a
     bytes-like object holding the associated data.  Note that some
     systems (in particular, systems without *note CMSG_SPACE(): 1bc6.)
     might support sending only one control message per call.  The
     'flags' argument defaults to 0 and has the same meaning as for
     *note send(): dd5.  If 'address' is supplied and not ‘None’, it
     sets a destination address for the message.  The return value is
     the number of bytes of non-ancillary data sent.

     The following function sends the list of file descriptors 'fds'
     over an *note AF_UNIX: 1955. socket, on systems which support the
     ‘SCM_RIGHTS’ mechanism.  See also *note recvmsg(): dd4.

          import socket, array

          def send_fds(sock, msg, fds):
              return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])

     *note Availability: 1ef7.: Unix, not WASI.

     Most Unix platforms.

     Raises an *note auditing event: 1a15. ‘socket.sendmsg’ with
     arguments ‘self’, ‘address’.

     Added in version 3.3.

     Changed in version 3.5: If the system call is interrupted and the
     signal handler does not raise an exception, the method now retries
     the system call instead of raising an *note InterruptedError: db6.
     exception (see PEP 475(15) for the rationale).

 -- Method: socket.sendmsg_afalg ([msg], *, op[, iv[, assoclen[,
          flags]]])

     Specialized version of *note sendmsg(): 479. for *note AF_ALG: cfd.
     socket.  Set mode, IV, AEAD associated data length and flags for
     ‘AF_ALG’ socket.

     *note Availability: 1ef7.: Linux >= 2.6.38.

     Added in version 3.6.

 -- Method: socket.sendfile (file, offset=0, count=None)

     Send a file until EOF is reached by using high-performance *note
     os.sendfile: b28. and return the total number of bytes which were
     sent.  'file' must be a regular file object opened in binary mode.
     If ‘os.sendfile’ is not available (e.g.  Windows) or 'file' is not
     a regular file *note send(): dd5. will be used instead.  'offset'
     tells from where to start reading the file.  If specified, 'count'
     is the total number of bytes to transmit as opposed to sending the
     file until EOF is reached.  File position is updated on return or
     also in case of error in which case *note file.tell(): 13f9. can be
     used to figure out the number of bytes which were sent.  The socket
     must be of *note SOCK_STREAM: 133c. type.  Non-blocking sockets are
     not supported.

     Added in version 3.5.

 -- Method: socket.set_inheritable (inheritable)

     Set the *note inheritable flag: f30. of the socket’s file
     descriptor or socket’s handle.

     Added in version 3.4.

 -- Method: socket.setblocking (flag)

     Set blocking or non-blocking mode of the socket: if 'flag' is
     false, the socket is set to non-blocking, else to blocking mode.

     This method is a shorthand for certain *note settimeout(): 362d.
     calls:

        * ‘sock.setblocking(True)’ is equivalent to
          ‘sock.settimeout(None)’

        * ‘sock.setblocking(False)’ is equivalent to
          ‘sock.settimeout(0.0)’

     Changed in version 3.7: The method no longer applies *note
     SOCK_NONBLOCK: c2a. flag on *note socket.type: c2c.

 -- Method: socket.settimeout (value)

     Set a timeout on blocking socket operations.  The 'value' argument
     can be a nonnegative floating-point number expressing seconds, or
     ‘None’.  If a non-zero value is given, subsequent socket operations
     will raise a *note timeout: 83a. exception if the timeout period
     'value' has elapsed before the operation has completed.  If zero is
     given, the socket is put in non-blocking mode.  If ‘None’ is given,
     the socket is put in blocking mode.

     For further information, please consult the *note notes on socket
     timeouts: 3672.

     Changed in version 3.7: The method no longer toggles *note
     SOCK_NONBLOCK: c2a. flag on *note socket.type: c2c.

 -- Method: socket.setsockopt (level, optname, value: int | Buffer)

 -- Method: socket.setsockopt (level, optname, None, optlen: int)

     Set the value of the given socket option (see the Unix manual page
     ‘setsockopt(2)(16)’).  The needed symbolic constants are defined in
     this module (SO_* etc.  <socket-unix-constants>).  The value can be
     an integer, ‘None’ or a *note bytes-like object: d55. representing
     a buffer.  In the latter case it is up to the caller to ensure that
     the bytestring contains the proper bits (see the optional built-in
     module *note struct: d5. for a way to encode C structures as
     bytestrings).  When 'value' is set to ‘None’, 'optlen' argument is
     required.  It’s equivalent to calling ‘setsockopt()’ C function
     with ‘optval=NULL’ and ‘optlen=optlen’.

     Changed in version 3.5: Writable *note bytes-like object: d55. is
     now accepted.

     Changed in version 3.6: setsockopt(level, optname, None, optlen:
     int) form added.

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.shutdown (how)

     Shut down one or both halves of the connection.  If 'how' is *note
     SHUT_RD: 365a, further receives are disallowed.  If 'how' is *note
     SHUT_WR: 365b, further sends are disallowed.  If 'how' is *note
     SHUT_RDWR: 365c, further sends and receives are disallowed.

     *note Availability: 1ef7.: not WASI.

 -- Method: socket.share (process_id)

     Duplicate a socket and prepare it for sharing with a target
     process.  The target process must be provided with 'process_id'.
     The resulting bytes object can then be passed to the target process
     using some form of interprocess communication and the socket can be
     recreated there using *note fromshare(): c27.  Once this method has
     been called, it is safe to close the socket since the operating
     system has already duplicated it for the target process.

     *note Availability: 1ef7.: Windows.

     Added in version 3.3.

Note that there are no methods ‘read()’ or ‘write()’; use *note recv():
dd2. and *note send(): dd5. without 'flags' argument instead.

Socket objects also have these (read-only) attributes that correspond to
the values given to the *note socket: dcf. constructor.

 -- Attribute: socket.family

     The socket family.

 -- Attribute: socket.type

     The socket type.

 -- Attribute: socket.proto

     The socket protocol.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/

   (2) https://peps.python.org/pep-0475/

   (3) https://manpages.debian.org/getsockopt(2)

   (4) https://msdn.microsoft.com/en-us/library/ms741621%28VS.85%29.aspx

   (5) https://manpages.debian.org/recv(2)

   (6) https://peps.python.org/pep-0475/

   (7) https://manpages.debian.org/recv(2)

   (8) https://peps.python.org/pep-0475/

   (9) https://peps.python.org/pep-0475/

   (10) https://manpages.debian.org/recv(2)

   (11) https://manpages.debian.org/recv(2)

   (12) https://peps.python.org/pep-0475/

   (13) https://peps.python.org/pep-0475/

   (14) https://peps.python.org/pep-0475/

   (15) https://peps.python.org/pep-0475/

   (16) https://manpages.debian.org/setsockopt(2)


File: python.info,  Node: Notes on socket timeouts,  Next: Example<7>,  Prev: Socket Objects,  Up: socket — Low-level networking interface

5.19.2.9 Notes on socket timeouts
.................................

A socket object can be in one of three modes: blocking, non-blocking, or
timeout.  Sockets are by default always created in blocking mode, but
this can be changed by calling *note setdefaulttimeout(): 3631.

   * In 'blocking mode', operations block until complete or the system
     returns an error (such as connection timed out).

   * In 'non-blocking mode', operations fail (with an error that is
     unfortunately system-dependent) if they cannot be completed
     immediately: functions from the *note select: c1. module can be
     used to know when and whether a socket is available for reading or
     writing.

   * In 'timeout mode', operations fail if they cannot be completed
     within the timeout specified for the socket (they raise a *note
     timeout: 83a. exception) or if the system returns an error.

     Note: At the operating system level, sockets in 'timeout mode' are
     internally set in non-blocking mode.  Also, the blocking and
     timeout modes are shared between file descriptors and socket
     objects that refer to the same network endpoint.  This
     implementation detail can have visible consequences if e.g.  you
     decide to use the *note fileno(): 366e. of a socket.

* Menu:

* Timeouts and the connect method::
* Timeouts and the accept method::


File: python.info,  Node: Timeouts and the connect method,  Next: Timeouts and the accept method,  Up: Notes on socket timeouts

5.19.2.10 Timeouts and the ‘connect’ method
...........................................

The *note connect(): dd1. operation is also subject to the timeout
setting, and in general it is recommended to call *note settimeout():
362d. before calling ‘connect()’ or pass a timeout parameter to *note
create_connection(): 675.  However, the system network stack may also
return a connection timeout error of its own regardless of any Python
socket timeout setting.


File: python.info,  Node: Timeouts and the accept method,  Prev: Timeouts and the connect method,  Up: Notes on socket timeouts

5.19.2.11 Timeouts and the ‘accept’ method
..........................................

If *note getdefaulttimeout(): 3662. is not *note None: 678, sockets
returned by the *note accept(): dd0. method inherit that timeout.
Otherwise, the behaviour depends on settings of the listening socket:

   * if the listening socket is in 'blocking mode' or in 'timeout mode',
     the socket returned by *note accept(): dd0. is in 'blocking mode';

   * if the listening socket is in 'non-blocking mode', whether the
     socket returned by *note accept(): dd0. is in blocking or
     non-blocking mode is operating system-dependent.  If you want to
     ensure cross-platform behaviour, it is recommended you manually
     override this setting.


File: python.info,  Node: Example<7>,  Prev: Notes on socket timeouts,  Up: socket — Low-level networking interface

5.19.2.12 Example
.................

Here are four minimal example programs using the TCP/IP protocol: a
server that echoes all data that it receives back (servicing only one
client), and a client using it.  Note that a server must perform the
sequence *note socket(): dcf, *note bind(): 158a, *note listen(): e92,
*note accept(): dd0. (possibly repeating the ‘accept()’ to service more
than one client), while a client only needs the sequence ‘socket()’,
*note connect(): dd1.  Also note that the server does not *note
sendall(): dd6./*note recv(): dd2. on the socket it is listening on but
on the new socket returned by ‘accept()’.

The first two examples support IPv4 only.

     # Echo server program
     import socket

     HOST = ''                 # Symbolic name meaning all available interfaces
     PORT = 50007              # Arbitrary non-privileged port
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
         s.bind((HOST, PORT))
         s.listen(1)
         conn, addr = s.accept()
         with conn:
             print('Connected by', addr)
             while True:
                 data = conn.recv(1024)
                 if not data: break
                 conn.sendall(data)

     # Echo client program
     import socket

     HOST = 'daring.cwi.nl'    # The remote host
     PORT = 50007              # The same port as used by the server
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
         s.connect((HOST, PORT))
         s.sendall(b'Hello, world')
         data = s.recv(1024)
     print('Received', repr(data))

The next two examples are identical to the above two, but support both
IPv4 and IPv6.  The server side will listen to the first address family
available (it should listen to both instead).  On most of IPv6-ready
systems, IPv6 will take precedence and the server may not accept IPv4
traffic.  The client side will try to connect to all the addresses
returned as a result of the name resolution, and sends traffic to the
first one connected successfully.

     # Echo server program
     import socket
     import sys

     HOST = None               # Symbolic name meaning all available interfaces
     PORT = 50007              # Arbitrary non-privileged port
     s = None
     for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                   socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
         af, socktype, proto, canonname, sa = res
         try:
             s = socket.socket(af, socktype, proto)
         except OSError as msg:
             s = None
             continue
         try:
             s.bind(sa)
             s.listen(1)
         except OSError as msg:
             s.close()
             s = None
             continue
         break
     if s is None:
         print('could not open socket')
         sys.exit(1)
     conn, addr = s.accept()
     with conn:
         print('Connected by', addr)
         while True:
             data = conn.recv(1024)
             if not data: break
             conn.send(data)

     # Echo client program
     import socket
     import sys

     HOST = 'daring.cwi.nl'    # The remote host
     PORT = 50007              # The same port as used by the server
     s = None
     for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
         af, socktype, proto, canonname, sa = res
         try:
             s = socket.socket(af, socktype, proto)
         except OSError as msg:
             s = None
             continue
         try:
             s.connect(sa)
         except OSError as msg:
             s.close()
             s = None
             continue
         break
     if s is None:
         print('could not open socket')
         sys.exit(1)
     with s:
         s.sendall(b'Hello, world')
         data = s.recv(1024)
     print('Received', repr(data))

The next example shows how to write a very simple network sniffer with
raw sockets on Windows.  The example requires administrator privileges
to modify the interface:

     import socket

     # the public network interface
     HOST = socket.gethostbyname(socket.gethostname())

     # create a raw socket and bind it to the public interface
     s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_IP)
     s.bind((HOST, 0))

     # Include IP headers
     s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, 1)

     # receive all packets
     s.ioctl(socket.SIO_RCVALL, socket.RCVALL_ON)

     # receive a packet
     print(s.recvfrom(65565))

     # disabled promiscuous mode
     s.ioctl(socket.SIO_RCVALL, socket.RCVALL_OFF)

The next example shows how to use the socket interface to communicate to
a CAN network using the raw socket protocol.  To use CAN with the
broadcast manager protocol instead, open a socket with:

     socket.socket(socket.AF_CAN, socket.SOCK_DGRAM, socket.CAN_BCM)

After binding (‘CAN_RAW’) or connecting (*note CAN_BCM: fdc.) the
socket, you can use the *note socket.send(): dd5. and *note
socket.recv(): dd2. operations (and their counterparts) on the socket
object as usual.

This last example might require special privileges:

     import socket
     import struct


     # CAN frame packing/unpacking (see 'struct can_frame' in <linux/can.h>)

     can_frame_fmt = "=IB3x8s"
     can_frame_size = struct.calcsize(can_frame_fmt)

     def build_can_frame(can_id, data):
         can_dlc = len(data)
         data = data.ljust(8, b'\x00')
         return struct.pack(can_frame_fmt, can_id, can_dlc, data)

     def dissect_can_frame(frame):
         can_id, can_dlc, data = struct.unpack(can_frame_fmt, frame)
         return (can_id, can_dlc, data[:can_dlc])


     # create a raw socket and bind it to the 'vcan0' interface
     s = socket.socket(socket.AF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
     s.bind(('vcan0',))

     while True:
         cf, addr = s.recvfrom(can_frame_size)

         print('Received: can_id=%x, can_dlc=%x, data=%s' % dissect_can_frame(cf))

         try:
             s.send(cf)
         except OSError:
             print('Error sending CAN frame')

         try:
             s.send(build_can_frame(0x01, b'\x01\x02\x03'))
         except OSError:
             print('Error sending CAN frame')

Running an example several times with too small delay between
executions, could lead to this error:

     OSError: [Errno 98] Address already in use

This is because the previous execution has left the socket in a
‘TIME_WAIT’ state, and can’t be immediately reused.

There is a ‘socket’ flag to set, in order to prevent this,
‘socket.SO_REUSEADDR’:

     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     s.bind((HOST, PORT))

the ‘SO_REUSEADDR’ flag tells the kernel to reuse a local socket in
‘TIME_WAIT’ state, without waiting for its natural timeout to expire.

See also
........

For an introduction to socket programming (in C), see the following
papers:

   - 'An Introductory 4.3BSD Interprocess Communication Tutorial', by
     Stuart Sechrest

   - 'An Advanced 4.3BSD Interprocess Communication Tutorial', by Samuel
     J. Leffler et al,

both in the UNIX Programmer’s Manual, Supplementary Documents 1
(sections PS1:7 and PS1:8).  The platform-specific reference material
for the various socket-related system calls are also a valuable source
of information on the details of socket semantics.  For Unix, refer to
the manual pages; for Windows, see the WinSock (or Winsock 2)
specification.  For IPv6-ready APIs, readers may want to refer to RFC
3493(1) titled Basic Socket Interface Extensions for IPv6.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3493.html


File: python.info,  Node: ssl — TLS/SSL wrapper for socket objects,  Next: select — Waiting for I/O completion,  Prev: socket — Low-level networking interface,  Up: Networking and Interprocess Communication

5.19.3 ‘ssl’ — TLS/SSL wrapper for socket objects
-------------------------------------------------

'Source code:' Lib/ssl.py(1)

__________________________________________________________________

This module provides access to Transport Layer Security (often known as
“Secure Sockets Layer”) encryption and peer authentication facilities
for network sockets, both client-side and server-side.  This module uses
the OpenSSL library.  It is available on all modern Unix systems,
Windows, macOS, and probably additional platforms, as long as OpenSSL is
installed on that platform.

     Note: Some behavior may be platform dependent, since calls are made
     to the operating system socket APIs.  The installed version of
     OpenSSL may also cause variations in behavior.  For example,
     TLSv1.3 comes with OpenSSL version 1.1.1.

     Warning: Don’t use this module without reading the *note Security
     considerations: 3564.  Doing so may lead to a false sense of
     security, as the default settings of the ssl module are not
     necessarily appropriate for your application.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

This section documents the objects and functions in the ‘ssl’ module;
for more general information about TLS, SSL, and certificates, the
reader is referred to the documents in the “See Also” section at the
bottom.

This module provides a class, *note ssl.SSLSocket: 8f3, which is derived
from the *note socket.socket: dcf. type, and provides a socket-like
wrapper that also encrypts and decrypts the data going over the socket
with SSL. It supports additional methods such as ‘getpeercert()’, which
retrieves the certificate of the other side of the connection,
‘cipher()’, which retrieves the cipher being used for the secure
connection or ‘get_verified_chain()’, ‘get_unverified_chain()’ which
retrieves certificate chain.

For more sophisticated applications, the *note ssl.SSLContext: 294.
class helps manage settings and certificates, which can then be
inherited by SSL sockets created through the *note
SSLContext.wrap_socket(): 528. method.

Changed in version 3.5.3: Updated to support linking with OpenSSL 1.1.0

Changed in version 3.6: OpenSSL 0.9.8, 1.0.0 and 1.0.1 are deprecated
and no longer supported.  In the future the ssl module will require at
least OpenSSL 1.0.2 or 1.1.0.

Changed in version 3.10: PEP 644(2) has been implemented.  The ssl
module requires OpenSSL 1.1.1 or newer.

Use of deprecated constants and functions result in deprecation
warnings.

* Menu:

* Functions, constants, and exceptions: Functions constants and exceptions.
* SSL sockets::
* SSL contexts::
* Certificates::
* Examples: Examples<20>.
* Notes on non-blocking sockets::
* Memory BIO support::
* SSL session::
* Security considerations: Security considerations<2>.
* TLS 1.3: TLS 1 3.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ssl.py

   (2) https://peps.python.org/pep-0644/


File: python.info,  Node: Functions constants and exceptions,  Next: SSL sockets,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.1 Functions, constants, and exceptions
.............................................

* Menu:

* Socket creation::
* Context creation::
* Exceptions: Exceptions<16>.
* Random generation::
* Certificate handling::
* Constants: Constants<9>.


File: python.info,  Node: Socket creation,  Next: Context creation,  Up: Functions constants and exceptions

5.19.3.2 Socket creation
........................

Instances of *note SSLSocket: 8f3. must be created using the *note
SSLContext.wrap_socket(): 528. method.  The helper function *note
create_default_context(): 155. returns a new context with secure default
settings.

Client socket example with default context and IPv4/IPv6 dual stack:

     import socket
     import ssl

     hostname = 'www.python.org'
     context = ssl.create_default_context()

     with socket.create_connection((hostname, 443)) as sock:
         with context.wrap_socket(sock, server_hostname=hostname) as ssock:
             print(ssock.version())

Client socket example with custom context and IPv4:

     hostname = 'www.python.org'
     # PROTOCOL_TLS_CLIENT requires valid cert chain and hostname
     context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
     context.load_verify_locations('path/to/cabundle.pem')

     with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock:
         with context.wrap_socket(sock, server_hostname=hostname) as ssock:
             print(ssock.version())

Server socket example listening on localhost IPv4:

     context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
     context.load_cert_chain('/path/to/certchain.pem', '/path/to/private.key')

     with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock:
         sock.bind(('127.0.0.1', 8443))
         sock.listen(5)
         with context.wrap_socket(sock, server_side=True) as ssock:
             conn, addr = ssock.accept()
             ...


File: python.info,  Node: Context creation,  Next: Exceptions<16>,  Prev: Socket creation,  Up: Functions constants and exceptions

5.19.3.3 Context creation
.........................

A convenience function helps create *note SSLContext: 294. objects for
common purposes.

 -- Function: ssl.create_default_context (purpose=Purpose.SERVER_AUTH,
          *, cafile=None, capath=None, cadata=None)

     Return a new *note SSLContext: 294. object with default settings
     for the given 'purpose'.  The settings are chosen by the ‘ssl’
     module, and usually represent a higher security level than when
     calling the ‘SSLContext’ constructor directly.

     'cafile', 'capath', 'cadata' represent optional CA certificates to
     trust for certificate verification, as in *note
     SSLContext.load_verify_locations(): f22.  If all three are *note
     None: 678, this function can choose to trust the system’s default
     CA certificates instead.

     The settings are: *note PROTOCOL_TLS_CLIENT: 879. or *note
     PROTOCOL_TLS_SERVER: 87a, *note OP_NO_SSLv2: 83f, and *note
     OP_NO_SSLv3: 840. with high encryption cipher suites without RC4
     and without unauthenticated cipher suites.  Passing *note
     SERVER_AUTH: fec. as 'purpose' sets *note verify_mode: 3680. to
     *note CERT_REQUIRED: 3681. and either loads CA certificates (when
     at least one of 'cafile', 'capath' or 'cadata' is given) or uses
     *note SSLContext.load_default_certs(): feb. to load default CA
     certificates.

     When *note keylog_filename: 3682. is supported and the environment
     variable ‘SSLKEYLOGFILE’ is set, ‘create_default_context()’ enables
     key logging.

     The default settings for this context include *note
     VERIFY_X509_PARTIAL_CHAIN: 156. and *note VERIFY_X509_STRICT: 157.
     These make the underlying OpenSSL implementation behave more like a
     conforming implementation of RFC 5280(1), in exchange for a small
     amount of incompatibility with older X.509 certificates.

          Note: The protocol, options, cipher and other settings may
          change to more restrictive values anytime without prior
          deprecation.  The values represent a fair balance between
          compatibility and security.

          If your application needs specific settings, you should create
          a *note SSLContext: 294. and apply the settings yourself.

          Note: If you find that when certain older clients or servers
          attempt to connect with a *note SSLContext: 294. created by
          this function that they get an error stating “Protocol or
          cipher suite mismatch”, it may be that they only support
          SSL3.0 which this function excludes using the *note
          OP_NO_SSLv3: 840.  SSL3.0 is widely considered to be
          completely broken(2).  If you still wish to continue to use
          this function but still allow SSL 3.0 connections you can
          re-enable them using:

               ctx = ssl.create_default_context(Purpose.CLIENT_AUTH)
               ctx.options &= ~ssl.OP_NO_SSLv3

          Note: This context enables *note VERIFY_X509_STRICT: 157. by
          default, which may reject pre- RFC 5280(3) or malformed
          certificates that the underlying OpenSSL implementation
          otherwise would accept.  While disabling this is not
          recommended, you can do so using:

               ctx = ssl.create_default_context()
               ctx.verify_flags &= ~ssl.VERIFY_X509_STRICT

     Added in version 3.4.

     Changed in version 3.4.4: RC4 was dropped from the default cipher
     string.

     Changed in version 3.6: ChaCha20/Poly1305 was added to the default
     cipher string.

     3DES was dropped from the default cipher string.

     Changed in version 3.8: Support for key logging to ‘SSLKEYLOGFILE’
     was added.

     Changed in version 3.10: The context now uses *note
     PROTOCOL_TLS_CLIENT: 879. or *note PROTOCOL_TLS_SERVER: 87a.
     protocol instead of generic *note PROTOCOL_TLS: 3683.

     Changed in version 3.13: The context now uses *note
     VERIFY_X509_PARTIAL_CHAIN: 156. and *note VERIFY_X509_STRICT: 157.
     in its default verify flags.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5280.html

   (2) https://en.wikipedia.org/wiki/POODLE

   (3) https://datatracker.ietf.org/doc/html/rfc5280.html


File: python.info,  Node: Exceptions<16>,  Next: Random generation,  Prev: Context creation,  Up: Functions constants and exceptions

5.19.3.4 Exceptions
...................

 -- Exception: ssl.SSLError

     Raised to signal an error from the underlying SSL implementation
     (currently provided by the OpenSSL library).  This signifies some
     problem in the higher-level encryption and authentication layer
     that’s superimposed on the underlying network connection.  This
     error is a subtype of *note OSError: 41a.  The error code and
     message of ‘SSLError’ instances are provided by the OpenSSL
     library.

     Changed in version 3.3: ‘SSLError’ used to be a subtype of *note
     socket.error: 1093.

      -- Attribute: library

          A string mnemonic designating the OpenSSL submodule in which
          the error occurred, such as ‘SSL’, ‘PEM’ or ‘X509’.  The range
          of possible values depends on the OpenSSL version.

          Added in version 3.3.

      -- Attribute: reason

          A string mnemonic designating the reason this error occurred,
          for example ‘CERTIFICATE_VERIFY_FAILED’.  The range of
          possible values depends on the OpenSSL version.

          Added in version 3.3.

 -- Exception: ssl.SSLZeroReturnError

     A subclass of *note SSLError: 12c0. raised when trying to read or
     write and the SSL connection has been closed cleanly.  Note that
     this doesn’t mean that the underlying transport (read TCP) has been
     closed.

     Added in version 3.3.

 -- Exception: ssl.SSLWantReadError

     A subclass of *note SSLError: 12c0. raised by a *note non-blocking
     SSL socket: 3686. when trying to read or write data, but more data
     needs to be received on the underlying TCP transport before the
     request can be fulfilled.

     Added in version 3.3.

 -- Exception: ssl.SSLWantWriteError

     A subclass of *note SSLError: 12c0. raised by a *note non-blocking
     SSL socket: 3686. when trying to read or write data, but more data
     needs to be sent on the underlying TCP transport before the request
     can be fulfilled.

     Added in version 3.3.

 -- Exception: ssl.SSLSyscallError

     A subclass of *note SSLError: 12c0. raised when a system error was
     encountered while trying to fulfill an operation on a SSL socket.
     Unfortunately, there is no easy way to inspect the original errno
     number.

     Added in version 3.3.

 -- Exception: ssl.SSLEOFError

     A subclass of *note SSLError: 12c0. raised when the SSL connection
     has been terminated abruptly.  Generally, you shouldn’t try to
     reuse the underlying transport when this error is encountered.

     Added in version 3.3.

 -- Exception: ssl.SSLCertVerificationError

     A subclass of *note SSLError: 12c0. raised when certificate
     validation has failed.

     Added in version 3.7.

      -- Attribute: verify_code

          A numeric error number that denotes the verification error.

      -- Attribute: verify_message

          A human readable string of the verification error.

 -- Exception: ssl.CertificateError

     An alias for *note SSLCertVerificationError: b9a.

     Changed in version 3.7: The exception is now an alias for *note
     SSLCertVerificationError: b9a.


File: python.info,  Node: Random generation,  Next: Certificate handling,  Prev: Exceptions<16>,  Up: Functions constants and exceptions

5.19.3.5 Random generation
..........................

 -- Function: ssl.RAND_bytes (num, /)

     Return 'num' cryptographically strong pseudo-random bytes.  Raises
     an *note SSLError: 12c0. if the PRNG has not been seeded with
     enough data or if the operation is not supported by the current
     RAND method.  *note RAND_status(): 1a24. can be used to check the
     status of the PRNG and *note RAND_add(): 368c. can be used to seed
     the PRNG.

     For almost all applications *note os.urandom(): 526. is preferable.

     Read the Wikipedia article, Cryptographically secure pseudorandom
     number generator (CSPRNG)(1), to get the requirements of a
     cryptographically strong generator.

     Added in version 3.3.

 -- Function: ssl.RAND_status ()

     Return ‘True’ if the SSL pseudo-random number generator has been
     seeded with ‘enough’ randomness, and ‘False’ otherwise.  You can
     use ‘ssl.RAND_egd()’ and *note ssl.RAND_add(): 368c. to increase
     the randomness of the pseudo-random number generator.

 -- Function: ssl.RAND_add (bytes, entropy, /)

     Mix the given 'bytes' into the SSL pseudo-random number generator.
     The parameter 'entropy' (a float) is a lower bound on the entropy
     contained in string (so you can always use ‘0.0’).  See RFC 1750(2)
     for more information on sources of entropy.

     Changed in version 3.5: Writable *note bytes-like object: d55. is
     now accepted.

   ---------- Footnotes ----------

   (1) 
https://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator

   (2) https://datatracker.ietf.org/doc/html/rfc1750.html


File: python.info,  Node: Certificate handling,  Next: Constants<9>,  Prev: Random generation,  Up: Functions constants and exceptions

5.19.3.6 Certificate handling
.............................

 -- Function: ssl.cert_time_to_seconds (cert_time)

     Return the time in seconds since the epoch, given the ‘cert_time’
     string representing the “notBefore” or “notAfter” date from a
     certificate in ‘"%b %d %H:%M:%S %Y %Z"’ strptime format (C locale).

     Here’s an example:

          >>> import ssl
          >>> import datetime as dt
          >>> timestamp = ssl.cert_time_to_seconds("Jan  5 09:34:43 2018 GMT")
          >>> timestamp
          1515144883
          >>> print(dt.datetime.fromtimestamp(timestamp, dt.UTC))
          2018-01-05 09:34:43+00:00

     “notBefore” or “notAfter” dates must use GMT ( RFC 5280(1)).

     Changed in version 3.5: Interpret the input time as a time in UTC
     as specified by ‘GMT’ timezone in the input string.  Local timezone
     was used previously.  Return an integer (no fractions of a second
     in the input format)

 -- Function: ssl.get_server_certificate (addr,
          ssl_version=PROTOCOL_TLS_CLIENT, ca_certs=None[, timeout])

     Given the address ‘addr’ of an SSL-protected server, as a
     ('hostname', 'port-number') pair, fetches the server’s certificate,
     and returns it as a PEM-encoded string.  If ‘ssl_version’ is
     specified, uses that version of the SSL protocol to attempt to
     connect to the server.  If 'ca_certs' is specified, it should be a
     file containing a list of root certificates, the same format as
     used for the 'cafile' parameter in *note
     SSLContext.load_verify_locations(): f22.  The call will attempt to
     validate the server certificate against that set of root
     certificates, and will fail if the validation attempt fails.  A
     timeout can be specified with the ‘timeout’ parameter.

     Changed in version 3.3: This function is now IPv6-compatible.

     Changed in version 3.5: The default 'ssl_version' is changed from
     *note PROTOCOL_SSLv3: 368e. to *note PROTOCOL_TLS: 3683. for
     maximum compatibility with modern servers.

     Changed in version 3.10: The 'timeout' parameter was added.

 -- Function: ssl.DER_cert_to_PEM_cert (der_cert_bytes)

     Given a certificate as a DER-encoded blob of bytes, returns a
     PEM-encoded string version of the same certificate.

 -- Function: ssl.PEM_cert_to_DER_cert (pem_cert_string)

     Given a certificate as an ASCII PEM string, returns a DER-encoded
     sequence of bytes for that same certificate.

 -- Function: ssl.get_default_verify_paths ()

     Returns a named tuple with paths to OpenSSL’s default cafile and
     capath.  The paths are the same as used by *note
     SSLContext.set_default_verify_paths(): fe4.  The return value is a
     *note named tuple: 651. ‘DefaultVerifyPaths’:

        * ‘cafile’ - resolved path to cafile or ‘None’ if the file
          doesn’t exist,

        * ‘capath’ - resolved path to capath or ‘None’ if the directory
          doesn’t exist,

        * ‘openssl_cafile_env’ - OpenSSL’s environment key that points
          to a cafile,

        * ‘openssl_cafile’ - hard coded path to a cafile,

        * ‘openssl_capath_env’ - OpenSSL’s environment key that points
          to a capath,

        * ‘openssl_capath’ - hard coded path to a capath directory

     Added in version 3.4.

 -- Function: ssl.enum_certificates (store_name)

     Retrieve certificates from Windows’ system cert store.
     'store_name' may be one of ‘CA’, ‘ROOT’ or ‘MY’.  Windows may
     provide additional cert stores, too.

     The function returns a list of (cert_bytes, encoding_type, trust)
     tuples.  The encoding_type specifies the encoding of cert_bytes.
     It is either ‘x509_asn’ for X.509 ASN.1 data or ‘pkcs_7_asn’ for
     PKCS#7 ASN.1 data.  Trust specifies the purpose of the certificate
     as a set of OIDS or exactly ‘True’ if the certificate is
     trustworthy for all purposes.

     Example:

          >>> ssl.enum_certificates("CA")
          [(b'data...', 'x509_asn', {'1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2'}),
           (b'data...', 'x509_asn', True)]

     *note Availability: 1ef7.: Windows.

     Added in version 3.4.

 -- Function: ssl.enum_crls (store_name)

     Retrieve CRLs from Windows’ system cert store.  'store_name' may be
     one of ‘CA’, ‘ROOT’ or ‘MY’.  Windows may provide additional cert
     stores, too.

     The function returns a list of (cert_bytes, encoding_type, trust)
     tuples.  The encoding_type specifies the encoding of cert_bytes.
     It is either ‘x509_asn’ for X.509 ASN.1 data or ‘pkcs_7_asn’ for
     PKCS#7 ASN.1 data.

     *note Availability: 1ef7.: Windows.

     Added in version 3.4.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5280.html


File: python.info,  Node: Constants<9>,  Prev: Certificate handling,  Up: Functions constants and exceptions

5.19.3.7 Constants
..................

     All constants are now *note enum.IntEnum: d06. or *note
     enum.IntFlag: cc1. collections.

     Added in version 3.6.

 -- Data: ssl.CERT_NONE

     Possible value for *note SSLContext.verify_mode: 3680.  Except for
     *note PROTOCOL_TLS_CLIENT: 879, it is the default mode.  With
     client-side sockets, just about any cert is accepted.  Validation
     errors, such as untrusted or expired cert, are ignored and do not
     abort the TLS/SSL handshake.

     In server mode, no certificate is requested from the client, so the
     client does not send any for client cert authentication.

     See the discussion of *note Security considerations: 3564. below.

 -- Data: ssl.CERT_OPTIONAL

     Possible value for *note SSLContext.verify_mode: 3680.  In client
     mode, *note CERT_OPTIONAL: 3693. has the same meaning as *note
     CERT_REQUIRED: 3681.  It is recommended to use ‘CERT_REQUIRED’ for
     client-side sockets instead.

     In server mode, a client certificate request is sent to the client.
     The client may either ignore the request or send a certificate in
     order perform TLS client cert authentication.  If the client
     chooses to send a certificate, it is verified.  Any verification
     error immediately aborts the TLS handshake.

     Use of this setting requires a valid set of CA certificates to be
     passed to *note SSLContext.load_verify_locations(): f22.

 -- Data: ssl.CERT_REQUIRED

     Possible value for *note SSLContext.verify_mode: 3680.  In this
     mode, certificates are required from the other side of the socket
     connection; an *note SSLError: 12c0. will be raised if no
     certificate is provided, or if its validation fails.  This mode is
     'not' sufficient to verify a certificate in client mode as it does
     not match hostnames.  *note check_hostname: 3694. must be enabled
     as well to verify the authenticity of a cert.  *note
     PROTOCOL_TLS_CLIENT: 879. uses *note CERT_REQUIRED: 3681. and
     enables ‘check_hostname’ by default.

     With server socket, this mode provides mandatory TLS client cert
     authentication.  A client certificate request is sent to the client
     and the client must provide a valid and trusted certificate.

     Use of this setting requires a valid set of CA certificates to be
     passed to *note SSLContext.load_verify_locations(): f22.

 -- Class: ssl.VerifyMode

     *note enum.IntEnum: d06. collection of CERT_* constants.

     Added in version 3.6.

 -- Data: ssl.VERIFY_DEFAULT

     Possible value for *note SSLContext.verify_flags: fe7.  In this
     mode, certificate revocation lists (CRLs) are not checked.  By
     default OpenSSL does neither require nor verify CRLs.

     Added in version 3.4.

 -- Data: ssl.VERIFY_CRL_CHECK_LEAF

     Possible value for *note SSLContext.verify_flags: fe7.  In this
     mode, only the peer cert is checked but none of the intermediate CA
     certificates.  The mode requires a valid CRL that is signed by the
     peer cert’s issuer (its direct ancestor CA). If no proper CRL has
     been loaded with *note SSLContext.load_verify_locations: f22,
     validation will fail.

     Added in version 3.4.

 -- Data: ssl.VERIFY_CRL_CHECK_CHAIN

     Possible value for *note SSLContext.verify_flags: fe7.  In this
     mode, CRLs of all certificates in the peer cert chain are checked.

     Added in version 3.4.

 -- Data: ssl.VERIFY_X509_STRICT

     Possible value for *note SSLContext.verify_flags: fe7. to disable
     workarounds for broken X.509 certificates.

     Added in version 3.4.

 -- Data: ssl.VERIFY_ALLOW_PROXY_CERTS

     Possible value for *note SSLContext.verify_flags: fe7. to enables
     proxy certificate verification.

     Added in version 3.10.

 -- Data: ssl.VERIFY_X509_TRUSTED_FIRST

     Possible value for *note SSLContext.verify_flags: fe7.  It
     instructs OpenSSL to prefer trusted certificates when building the
     trust chain to validate a certificate.  This flag is enabled by
     default.

     Added in version 3.4.4.

 -- Data: ssl.VERIFY_X509_PARTIAL_CHAIN

     Possible value for *note SSLContext.verify_flags: fe7.  It
     instructs OpenSSL to accept intermediate CAs in the trust store to
     be treated as trust-anchors, in the same way as the self-signed
     root CA certificates.  This makes it possible to trust certificates
     issued by an intermediate CA without having to trust its ancestor
     root CA.

     Added in version 3.10.

 -- Class: ssl.VerifyFlags

     *note enum.IntFlag: cc1. collection of VERIFY_* constants.

     Added in version 3.6.

 -- Data: ssl.PROTOCOL_TLS

     Selects the highest protocol version that both the client and
     server support.  Despite the name, this option can select both
     “SSL” and “TLS” protocols.

     Added in version 3.6.

     Deprecated since version 3.10: TLS clients and servers require
     different default settings for secure communication.  The generic
     TLS protocol constant is deprecated in favor of *note
     PROTOCOL_TLS_CLIENT: 879. and *note PROTOCOL_TLS_SERVER: 87a.

 -- Data: ssl.PROTOCOL_TLS_CLIENT

     Auto-negotiate the highest protocol version that both the client
     and server support, and configure the context client-side
     connections.  The protocol enables *note CERT_REQUIRED: 3681. and
     *note check_hostname: 3694. by default.

     Added in version 3.6.

 -- Data: ssl.PROTOCOL_TLS_SERVER

     Auto-negotiate the highest protocol version that both the client
     and server support, and configure the context server-side
     connections.

     Added in version 3.6.

 -- Data: ssl.PROTOCOL_SSLv23

     Alias for *note PROTOCOL_TLS: 3683.

     Deprecated since version 3.6: Use *note PROTOCOL_TLS: 3683.
     instead.

 -- Data: ssl.PROTOCOL_SSLv3

     Selects SSL version 3 as the channel encryption protocol.

     This protocol is not available if OpenSSL is compiled with the
     ‘no-ssl3’ option.

          Warning: SSL version 3 is insecure.  Its use is highly
          discouraged.

     Deprecated since version 3.6: OpenSSL has deprecated all version
     specific protocols.  Use the default protocol *note
     PROTOCOL_TLS_SERVER: 87a. or *note PROTOCOL_TLS_CLIENT: 879. with
     *note SSLContext.minimum_version: 877. and *note
     SSLContext.maximum_version: 878. instead.

 -- Data: ssl.PROTOCOL_TLSv1

     Selects TLS version 1.0 as the channel encryption protocol.

     Deprecated since version 3.6: OpenSSL has deprecated all version
     specific protocols.

 -- Data: ssl.PROTOCOL_TLSv1_1

     Selects TLS version 1.1 as the channel encryption protocol.
     Available only with openssl version 1.0.1+.

     Added in version 3.4.

     Deprecated since version 3.6: OpenSSL has deprecated all version
     specific protocols.

 -- Data: ssl.PROTOCOL_TLSv1_2

     Selects TLS version 1.2 as the channel encryption protocol.
     Available only with openssl version 1.0.1+.

     Added in version 3.4.

     Deprecated since version 3.6: OpenSSL has deprecated all version
     specific protocols.

 -- Data: ssl.OP_ALL

     Enables workarounds for various bugs present in other SSL
     implementations.  This option is set by default.  It does not
     necessarily set the same flags as OpenSSL’s ‘SSL_OP_ALL’ constant.

     Added in version 3.2.

 -- Data: ssl.OP_NO_SSLv2

     Prevents an SSLv2 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing SSLv2 as the protocol version.

     Added in version 3.2.

     Deprecated since version 3.6: SSLv2 is deprecated

 -- Data: ssl.OP_NO_SSLv3

     Prevents an SSLv3 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing SSLv3 as the protocol version.

     Added in version 3.2.

     Deprecated since version 3.6: SSLv3 is deprecated

 -- Data: ssl.OP_NO_TLSv1

     Prevents a TLSv1 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing TLSv1 as the protocol version.

     Added in version 3.2.

     Deprecated since version 3.7: The option is deprecated since
     OpenSSL 1.1.0, use the new *note SSLContext.minimum_version: 877.
     and *note SSLContext.maximum_version: 878. instead.

 -- Data: ssl.OP_NO_TLSv1_1

     Prevents a TLSv1.1 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing TLSv1.1 as the protocol version.  Available only with
     openssl version 1.0.1+.

     Added in version 3.4.

     Deprecated since version 3.7: The option is deprecated since
     OpenSSL 1.1.0.

 -- Data: ssl.OP_NO_TLSv1_2

     Prevents a TLSv1.2 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing TLSv1.2 as the protocol version.  Available only with
     openssl version 1.0.1+.

     Added in version 3.4.

     Deprecated since version 3.7: The option is deprecated since
     OpenSSL 1.1.0.

 -- Data: ssl.OP_NO_TLSv1_3

     Prevents a TLSv1.3 connection.  This option is only applicable in
     conjunction with *note PROTOCOL_TLS: 3683.  It prevents the peers
     from choosing TLSv1.3 as the protocol version.  TLS 1.3 is
     available with OpenSSL 1.1.1 or later.  When Python has been
     compiled against an older version of OpenSSL, the flag defaults to
     '0'.

     Added in version 3.6.3.

     Deprecated since version 3.7: The option is deprecated since
     OpenSSL 1.1.0.  It was added to 2.7.15 and 3.6.3 for backwards
     compatibility with OpenSSL 1.0.2.

 -- Data: ssl.OP_NO_RENEGOTIATION

     Disable all renegotiation in TLSv1.2 and earlier.  Do not send
     HelloRequest messages, and ignore renegotiation requests via
     ClientHello.

     This option is only available with OpenSSL 1.1.0h and later.

     Added in version 3.7.

 -- Data: ssl.OP_CIPHER_SERVER_PREFERENCE

     Use the server’s cipher ordering preference, rather than the
     client’s.  This option has no effect on client sockets and SSLv2
     server sockets.

     Added in version 3.3.

 -- Data: ssl.OP_SINGLE_DH_USE

     Prevents reuse of the same DH key for distinct SSL sessions.  This
     improves forward secrecy but requires more computational resources.
     This option only applies to server sockets.

     Added in version 3.3.

 -- Data: ssl.OP_SINGLE_ECDH_USE

     Prevents reuse of the same ECDH key for distinct SSL sessions.
     This improves forward secrecy but requires more computational
     resources.  This option only applies to server sockets.

     Added in version 3.3.

 -- Data: ssl.OP_ENABLE_MIDDLEBOX_COMPAT

     Send dummy Change Cipher Spec (CCS) messages in TLS 1.3 handshake
     to make a TLS 1.3 connection look more like a TLS 1.2 connection.

     This option is only available with OpenSSL 1.1.1 and later.

     Added in version 3.8.

 -- Data: ssl.OP_NO_COMPRESSION

     Disable compression on the SSL channel.  This is useful if the
     application protocol supports its own compression scheme.

     Added in version 3.3.

 -- Class: ssl.Options

     *note enum.IntFlag: cc1. collection of OP_* constants.

 -- Data: ssl.OP_NO_TICKET

     Prevent client side from requesting a session ticket.

     Added in version 3.6.

 -- Data: ssl.OP_IGNORE_UNEXPECTED_EOF

     Ignore unexpected shutdown of TLS connections.

     This option is only available with OpenSSL 3.0.0 and later.

     Added in version 3.10.

 -- Data: ssl.OP_ENABLE_KTLS

     Enable the use of the kernel TLS. To benefit from the feature,
     OpenSSL must have been compiled with support for it, and the
     negotiated cipher suites and extensions must be supported by it (a
     list of supported ones may vary by platform and kernel version).

     Note that with enabled kernel TLS some cryptographic operations are
     performed by the kernel directly and not via any available OpenSSL
     Providers.  This might be undesirable if, for example, the
     application requires all cryptographic operations to be performed
     by the FIPS provider.

     This option is only available with OpenSSL 3.0.0 and later.

     Added in version 3.12.

 -- Data: ssl.OP_LEGACY_SERVER_CONNECT

     Allow legacy insecure renegotiation between OpenSSL and unpatched
     servers only.

     Added in version 3.12.

 -- Data: ssl.HAS_ALPN

     Whether the OpenSSL library has built-in support for the
     'Application-Layer Protocol Negotiation' TLS extension as described
     in RFC 7301(1).

     Added in version 3.5.

 -- Data: ssl.HAS_NEVER_CHECK_COMMON_NAME

     Whether the OpenSSL library has built-in support not checking
     subject common name and *note
     SSLContext.hostname_checks_common_name: b9b. is writeable.

     Added in version 3.7.

 -- Data: ssl.HAS_ECDH

     Whether the OpenSSL library has built-in support for the Elliptic
     Curve-based Diffie-Hellman key exchange.  This should be true
     unless the feature was explicitly disabled by the distributor.

     Added in version 3.3.

 -- Data: ssl.HAS_SNI

     Whether the OpenSSL library has built-in support for the 'Server
     Name Indication' extension (as defined in RFC 6066(2)).

     Added in version 3.2.

 -- Data: ssl.HAS_NPN

     Whether the OpenSSL library has built-in support for the 'Next
     Protocol Negotiation' as described in the Application Layer
     Protocol Negotiation(3).  When true, you can use the *note
     SSLContext.set_npn_protocols(): 302. method to advertise which
     protocols you want to support.

     Added in version 3.3.

 -- Data: ssl.HAS_SSLv2

     Whether the OpenSSL library has built-in support for the SSL 2.0
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_SSLv3

     Whether the OpenSSL library has built-in support for the SSL 3.0
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_TLSv1

     Whether the OpenSSL library has built-in support for the TLS 1.0
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_TLSv1_1

     Whether the OpenSSL library has built-in support for the TLS 1.1
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_TLSv1_2

     Whether the OpenSSL library has built-in support for the TLS 1.2
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_TLSv1_3

     Whether the OpenSSL library has built-in support for the TLS 1.3
     protocol.

     Added in version 3.7.

 -- Data: ssl.HAS_PSK

     Whether the OpenSSL library has built-in support for TLS-PSK.

     Added in version 3.13.

 -- Data: ssl.CHANNEL_BINDING_TYPES

     List of supported TLS channel binding types.  Strings in this list
     can be used as arguments to *note SSLSocket.get_channel_binding():
     1188.

     Added in version 3.3.

 -- Data: ssl.OPENSSL_VERSION

     The version string of the OpenSSL library loaded by the
     interpreter:

          >>> ssl.OPENSSL_VERSION
          'OpenSSL 1.0.2k  26 Jan 2017'

     Added in version 3.2.

 -- Data: ssl.OPENSSL_VERSION_INFO

     A tuple of five integers representing version information about the
     OpenSSL library:

          >>> ssl.OPENSSL_VERSION_INFO
          (1, 0, 2, 11, 15)

     Added in version 3.2.

 -- Data: ssl.OPENSSL_VERSION_NUMBER

     The raw version number of the OpenSSL library, as a single integer:

          >>> ssl.OPENSSL_VERSION_NUMBER
          268443839
          >>> hex(ssl.OPENSSL_VERSION_NUMBER)
          '0x100020bf'

     Added in version 3.2.

 -- Data: ssl.ALERT_DESCRIPTION_HANDSHAKE_FAILURE
 -- Data: ssl.ALERT_DESCRIPTION_INTERNAL_ERROR

 -- Data: ALERT_DESCRIPTION_*

     Alert Descriptions from RFC 5246(4) and others.  The IANA TLS Alert
     Registry(5) contains this list and references to the RFCs where
     their meaning is defined.

     Used as the return value of the callback function in *note
     SSLContext.set_servername_callback(): ff0.

     Added in version 3.4.

 -- Class: ssl.AlertDescription

     *note enum.IntEnum: d06. collection of ALERT_DESCRIPTION_*
     constants.

     Added in version 3.6.

 -- Data: Purpose.SERVER_AUTH

     Option for *note create_default_context(): 155. and *note
     SSLContext.load_default_certs(): feb.  This value indicates that
     the context may be used to authenticate web servers (therefore, it
     will be used to create client-side sockets).

     Added in version 3.4.

 -- Data: Purpose.CLIENT_AUTH

     Option for *note create_default_context(): 155. and *note
     SSLContext.load_default_certs(): feb.  This value indicates that
     the context may be used to authenticate web clients (therefore, it
     will be used to create server-side sockets).

     Added in version 3.4.

 -- Class: ssl.SSLErrorNumber

     *note enum.IntEnum: d06. collection of SSL_ERROR_* constants.

     Added in version 3.6.

 -- Class: ssl.TLSVersion

     *note enum.IntEnum: d06. collection of SSL and TLS versions for
     *note SSLContext.maximum_version: 878. and *note
     SSLContext.minimum_version: 877.

     Added in version 3.7.

 -- Attribute: TLSVersion.MINIMUM_SUPPORTED

 -- Attribute: TLSVersion.MAXIMUM_SUPPORTED

     The minimum or maximum supported SSL or TLS version.  These are
     magic constants.  Their values don’t reflect the lowest and highest
     available TLS/SSL versions.

 -- Attribute: TLSVersion.SSLv3

 -- Attribute: TLSVersion.TLSv1

 -- Attribute: TLSVersion.TLSv1_1

 -- Attribute: TLSVersion.TLSv1_2

 -- Attribute: TLSVersion.TLSv1_3

     SSL 3.0 to TLS 1.3.

     Deprecated since version 3.10: All *note TLSVersion: 36b3. members
     except *note TLSVersion.TLSv1_2: 36b9. and ‘TLSVersion.TLSv1_3’ are
     deprecated.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc7301.html

   (2) https://datatracker.ietf.org/doc/html/rfc6066.html

   (3) 
https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation

   (4) https://datatracker.ietf.org/doc/html/rfc5246.html

   (5) 
https://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-6


File: python.info,  Node: SSL sockets,  Next: SSL contexts,  Prev: Functions constants and exceptions,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.8 SSL sockets
....................

 -- Class: ssl.SSLSocket (socket.socket)

     SSL sockets provide the following methods of *note Socket Objects:
     3660.:

        - *note accept(): dd0.

        - *note bind(): 158a.

        - *note close(): d6c.

        - *note connect(): dd1.

        - *note detach(): 1262.

        - *note fileno(): 366e.

        - *note getpeername(): 35a8, *note getsockname(): 35a9.

        - *note getsockopt(): cfb, *note setsockopt(): cfc.

        - *note gettimeout(): 366f, *note settimeout(): 362d, *note
          setblocking(): 2d3a.

        - *note listen(): e92.

        - *note makefile(): 11e3.

        - *note recv(): dd2, *note recv_into(): 1367. (but passing a
          non-zero ‘flags’ argument is not allowed)

        - *note send(): dd5, *note sendall(): dd6. (with the same
          limitation)

        - *note sendfile(): e91. (but *note os.sendfile: b28. will be
          used for plain-text sockets only, else *note send(): dd5. will
          be used)

        - *note shutdown(): 365d.

     However, since the SSL (and TLS) protocol has its own framing atop
     of TCP, the SSL sockets abstraction can, in certain respects,
     diverge from the specification of normal, OS-level sockets.  See
     especially the *note notes on non-blocking sockets: 3686.

     Instances of ‘SSLSocket’ must be created using the *note
     SSLContext.wrap_socket(): 528. method.

     Changed in version 3.5: The ‘sendfile()’ method was added.

     Changed in version 3.5: The ‘shutdown()’ does not reset the socket
     timeout each time bytes are received or sent.  The socket timeout
     is now the maximum total duration of the shutdown.

     Deprecated since version 3.6: It is deprecated to create a
     ‘SSLSocket’ instance directly, use *note SSLContext.wrap_socket():
     528. to wrap a socket.

     Changed in version 3.7: ‘SSLSocket’ instances must to created with
     *note wrap_socket(): 528.  In earlier versions, it was possible to
     create instances directly.  This was never documented or officially
     supported.

     Changed in version 3.10: Python now uses ‘SSL_read_ex’ and
     ‘SSL_write_ex’ internally.  The functions support reading and
     writing of data larger than 2 GB. Writing zero-length data no
     longer fails with a protocol violation error.

SSL sockets also have the following additional methods and attributes:

 -- Method: SSLSocket.read (len=1024, buffer=None)

     Read up to 'len' bytes of data from the SSL socket and return the
     result as a ‘bytes’ instance.  If 'buffer' is specified, then read
     into the buffer instead, and return the number of bytes read.

     Raise *note SSLWantReadError: e9d. or *note SSLWantWriteError: e9e.
     if the socket is *note non-blocking: 3686. and the read would
     block.

     As at any time a re-negotiation is possible, a call to ‘read()’ can
     also cause write operations.

     Changed in version 3.5: The socket timeout is no longer reset each
     time bytes are received or sent.  The socket timeout is now the
     maximum total duration to read up to 'len' bytes.

     Deprecated since version 3.6: Use ‘recv()’ instead of ‘read()’.

 -- Method: SSLSocket.write (data)

     Write 'data' to the SSL socket and return the number of bytes
     written.  The 'data' argument must be an object supporting the
     buffer interface.

     Raise *note SSLWantReadError: e9d. or *note SSLWantWriteError: e9e.
     if the socket is *note non-blocking: 3686. and the write would
     block.

     As at any time a re-negotiation is possible, a call to ‘write()’
     can also cause read operations.

     Changed in version 3.5: The socket timeout is no longer reset each
     time bytes are received or sent.  The socket timeout is now the
     maximum total duration to write 'data'.

     Deprecated since version 3.6: Use ‘send()’ instead of ‘write()’.

     Note: The *note read(): ea2. and *note write(): ea3. methods are
     the low-level methods that read and write unencrypted,
     application-level data and decrypt/encrypt it to encrypted,
     wire-level data.  These methods require an active SSL connection,
     i.e.  the handshake was completed and *note SSLSocket.unwrap():
     36bc. was not called.

     Normally you should use the socket API methods like *note recv():
     dd2. and *note send(): dd5. instead of these methods.

 -- Method: SSLSocket.do_handshake (block=False)

     Perform the SSL setup handshake.

     If 'block' is true and the timeout obtained by *note gettimeout():
     366f. is zero, the socket is set in blocking mode until the
     handshake is performed.

     Changed in version 3.4: The handshake method also performs
     ‘match_hostname()’ when the *note check_hostname: 3694. attribute
     of the socket’s *note context: 36bd. is true.

     Changed in version 3.5: The socket timeout is no longer reset each
     time bytes are received or sent.  The socket timeout is now the
     maximum total duration of the handshake.

     Changed in version 3.7: Hostname or IP address is matched by
     OpenSSL during handshake.  The function ‘match_hostname()’ is no
     longer used.  In case OpenSSL refuses a hostname or IP address, the
     handshake is aborted early and a TLS alert message is sent to the
     peer.

 -- Method: SSLSocket.getpeercert (binary_form=False)

     If there is no certificate for the peer on the other end of the
     connection, return ‘None’.  If the SSL handshake hasn’t been done
     yet, raise *note ValueError: 202.

     If the ‘binary_form’ parameter is *note False: b4f, and a
     certificate was received from the peer, this method returns a *note
     dict: 256. instance.  If the certificate was not validated, the
     dict is empty.  If the certificate was validated, it returns a dict
     with several keys, amongst them ‘subject’ (the principal for which
     the certificate was issued) and ‘issuer’ (the principal issuing the
     certificate).  If a certificate contains an instance of the
     'Subject Alternative Name' extension (see RFC 3280(1)), there will
     also be a ‘subjectAltName’ key in the dictionary.

     The ‘subject’ and ‘issuer’ fields are tuples containing the
     sequence of relative distinguished names (RDNs) given in the
     certificate’s data structure for the respective fields, and each
     RDN is a sequence of name-value pairs.  Here is a real-world
     example:

          {'issuer': ((('countryName', 'IL'),),
                      (('organizationName', 'StartCom Ltd.'),),
                      (('organizationalUnitName',
                        'Secure Digital Certificate Signing'),),
                      (('commonName',
                        'StartCom Class 2 Primary Intermediate Server CA'),)),
           'notAfter': 'Nov 22 08:15:19 2013 GMT',
           'notBefore': 'Nov 21 03:09:52 2011 GMT',
           'serialNumber': '95F0',
           'subject': ((('description', '571208-SLe257oHY9fVQ07Z'),),
                       (('countryName', 'US'),),
                       (('stateOrProvinceName', 'California'),),
                       (('localityName', 'San Francisco'),),
                       (('organizationName', 'Electronic Frontier Foundation, Inc.'),),
                       (('commonName', '*.eff.org'),),
                       (('emailAddress', 'hostmaster@eff.org'),)),
           'subjectAltName': (('DNS', '*.eff.org'), ('DNS', 'eff.org')),
           'version': 3}

     If the ‘binary_form’ parameter is *note True: c2d, and a
     certificate was provided, this method returns the DER-encoded form
     of the entire certificate as a sequence of bytes, or *note None:
     678. if the peer did not provide a certificate.  Whether the peer
     provides a certificate depends on the SSL socket’s role:

        * for a client SSL socket, the server will always provide a
          certificate, regardless of whether validation was required;

        * for a server SSL socket, the client will only provide a
          certificate when requested by the server; therefore
          ‘getpeercert()’ will return *note None: 678. if you used *note
          CERT_NONE: 3692. (rather than *note CERT_OPTIONAL: 3693. or
          *note CERT_REQUIRED: 3681.).

     See also *note SSLContext.check_hostname: 3694.

     Changed in version 3.2: The returned dictionary includes additional
     items such as ‘issuer’ and ‘notBefore’.

     Changed in version 3.4: *note ValueError: 202. is raised when the
     handshake isn’t done.  The returned dictionary includes additional
     X509v3 extension items such as ‘crlDistributionPoints’, ‘caIssuers’
     and ‘OCSP’ URIs.

     Changed in version 3.9: IPv6 address strings no longer have a
     trailing new line.

 -- Method: SSLSocket.get_verified_chain ()

     Returns verified certificate chain provided by the other end of the
     SSL channel as a list of DER-encoded bytes.  If certificate
     verification was disabled method acts the same as *note
     get_unverified_chain(): 16e5.

     Added in version 3.13.

 -- Method: SSLSocket.get_unverified_chain ()

     Returns raw certificate chain provided by the other end of the SSL
     channel as a list of DER-encoded bytes.

     Added in version 3.13.

 -- Method: SSLSocket.cipher ()

     Returns a three-value tuple containing the name of the cipher being
     used, the version of the SSL protocol that defines its use, and the
     number of secret bits being used.  If no connection has been
     established, returns ‘None’.

 -- Method: SSLSocket.shared_ciphers ()

     Return the list of ciphers available in both the client and server.
     Each entry of the returned list is a three-value tuple containing
     the name of the cipher, the version of the SSL protocol that
     defines its use, and the number of secret bits the cipher uses.
     ‘shared_ciphers()’ returns ‘None’ if no connection has been
     established or the socket is a client socket.

     Added in version 3.5.

 -- Method: SSLSocket.compression ()

     Return the compression algorithm being used as a string, or ‘None’
     if the connection isn’t compressed.

     If the higher-level protocol supports its own compression
     mechanism, you can use *note OP_NO_COMPRESSION: 118a. to disable
     SSL-level compression.

     Added in version 3.3.

 -- Method: SSLSocket.get_channel_binding (cb_type='tls-unique')

     Get channel binding data for current connection, as a bytes object.
     Returns ‘None’ if not connected or the handshake has not been
     completed.

     The 'cb_type' parameter allow selection of the desired channel
     binding type.  Valid channel binding types are listed in the *note
     CHANNEL_BINDING_TYPES: 36ae. list.  Currently only the ‘tls-unique’
     channel binding, defined by RFC 5929(2), is supported.  *note
     ValueError: 202. will be raised if an unsupported channel binding
     type is requested.

     Added in version 3.3.

 -- Method: SSLSocket.selected_alpn_protocol ()

     Return the protocol that was selected during the TLS handshake.  If
     *note SSLContext.set_alpn_protocols(): e98. was not called, if the
     other party does not support ALPN, if this socket does not support
     any of the client’s proposed protocols, or if the handshake has not
     happened yet, ‘None’ is returned.

     Added in version 3.5.

 -- Method: SSLSocket.selected_npn_protocol ()

     Return the higher-level protocol that was selected during the
     TLS/SSL handshake.  If *note SSLContext.set_npn_protocols(): 302.
     was not called, or if the other party does not support NPN, or if
     the handshake has not yet happened, this will return ‘None’.

     Added in version 3.3.

     Deprecated since version 3.10: NPN has been superseded by ALPN

 -- Method: SSLSocket.unwrap ()

     Performs the SSL shutdown handshake, which removes the TLS layer
     from the underlying socket, and returns the underlying socket
     object.  This can be used to go from encrypted operation over a
     connection to unencrypted.  The returned socket should always be
     used for further communication with the other side of the
     connection, rather than the original socket.

 -- Method: SSLSocket.verify_client_post_handshake ()

     Requests post-handshake authentication (PHA) from a TLS 1.3 client.
     PHA can only be initiated for a TLS 1.3 connection from a
     server-side socket, after the initial TLS handshake and with PHA
     enabled on both sides, see *note SSLContext.post_handshake_auth:
     a3e.

     The method does not perform a cert exchange immediately.  The
     server-side sends a CertificateRequest during the next write event
     and expects the client to respond with a certificate on the next
     read event.

     If any precondition isn’t met (e.g.  not TLS 1.3, PHA not enabled),
     an *note SSLError: 12c0. is raised.

          Note: Only available with OpenSSL 1.1.1 and TLS 1.3 enabled.
          Without TLS 1.3 support, the method raises *note
          NotImplementedError: 228.

     Added in version 3.8.

 -- Method: SSLSocket.version ()

     Return the actual SSL protocol version negotiated by the connection
     as a string, or ‘None’ if no secure connection is established.  As
     of this writing, possible return values include ‘"SSLv2"’,
     ‘"SSLv3"’, ‘"TLSv1"’, ‘"TLSv1.1"’ and ‘"TLSv1.2"’.  Recent OpenSSL
     versions may define more return values.

     Added in version 3.5.

 -- Method: SSLSocket.pending ()

     Returns the number of already decrypted bytes available for read,
     pending on the connection.

 -- Attribute: SSLSocket.context

     The *note SSLContext: 294. object this SSL socket is tied to.

     Added in version 3.2.

 -- Attribute: SSLSocket.server_side

     A boolean which is ‘True’ for server-side sockets and ‘False’ for
     client-side sockets.

     Added in version 3.2.

 -- Attribute: SSLSocket.server_hostname

     Hostname of the server: *note str: 44f. type, or ‘None’ for
     server-side socket or if the hostname was not specified in the
     constructor.

     Added in version 3.2.

     Changed in version 3.7: The attribute is now always ASCII text.
     When ‘server_hostname’ is an internationalized domain name (IDN),
     this attribute now stores the A-label form (‘"xn--pythn-mua.org"’),
     rather than the U-label form (‘"pythön.org"’).

 -- Attribute: SSLSocket.session

     The *note SSLSession: d04. for this SSL connection.  The session is
     available for client and server side sockets after the TLS
     handshake has been performed.  For client sockets the session can
     be set before *note do_handshake(): ea1. has been called to reuse a
     session.

     Added in version 3.6.

 -- Attribute: SSLSocket.session_reused

     Added in version 3.6.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3280.html

   (2) https://datatracker.ietf.org/doc/html/rfc5929.html


File: python.info,  Node: SSL contexts,  Next: Certificates,  Prev: SSL sockets,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.9 SSL contexts
.....................

Added in version 3.2.

An SSL context holds various data longer-lived than single SSL
connections, such as SSL configuration options, certificate(s) and
private key(s).  It also manages a cache of SSL sessions for server-side
sockets, in order to speed up repeated connections from the same
clients.

 -- Class: ssl.SSLContext (protocol=None)

     Create a new SSL context.  You may pass 'protocol' which must be
     one of the ‘PROTOCOL_*’ constants defined in this module.  The
     parameter specifies which version of the SSL protocol to use.
     Typically, the server chooses a particular protocol version, and
     the client must adapt to the server’s choice.  Most of the versions
     are not interoperable with the other versions.  If not specified,
     the default is *note PROTOCOL_TLS: 3683.; it provides the most
     compatibility with other versions.

     Here’s a table showing which versions in a client (down the side)
     can connect to which versions in a server (along the top):

     'client' / 'server'          'SSLv2'          'SSLv3'          'TLS' (1)         'TLSv1'       'TLSv1.1'       'TLSv1.2'
                                                                                                                    
                                                                                                                    
     'SSLv2'                      yes              no               no (2)            no            no              no
                                                                                                                    
                                                                                                                    
     'SSLv3'                      no               yes              no (3)            no            no              no
                                                                                                                    
                                                                                                                    
     'TLS' ('SSLv23') (4)         no (5)           no (6)           yes               yes           yes             yes
                                                                                                                    
                                                                                                                    
     'TLSv1'                      no               no               yes               yes           no              no
                                                                                                                    
                                                                                                                    
     'TLSv1.1'                    no               no               yes               no            yes             no
                                                                                                                    
                                                                                                                    
     'TLSv1.2'                    no               no               yes               no            no              yes
                                                                                                                    

     See also
     ........

     *note create_default_context(): 155. lets the ‘ssl’ module choose
     security settings for a given purpose.

     Changed in version 3.6: The context is created with secure default
     values.  The options *note OP_NO_COMPRESSION: 118a, *note
     OP_CIPHER_SERVER_PREFERENCE: 118d, *note OP_SINGLE_DH_USE: 369f,
     *note OP_SINGLE_ECDH_USE: 36a0, *note OP_NO_SSLv2: 83f, and *note
     OP_NO_SSLv3: 840. (except for *note PROTOCOL_SSLv3: 368e.) are set
     by default.  The initial cipher suite list contains only ‘HIGH’
     ciphers, no ‘NULL’ ciphers and no ‘MD5’ ciphers.

     Deprecated since version 3.10: ‘SSLContext’ without protocol
     argument is deprecated.  The context class will either require
     *note PROTOCOL_TLS_CLIENT: 879. or *note PROTOCOL_TLS_SERVER: 87a.
     protocol in the future.

     Changed in version 3.10: The default cipher suites now include only
     secure AES and ChaCha20 ciphers with forward secrecy and security
     level 2.  RSA and DH keys with less than 2048 bits and ECC keys
     with less than 224 bits are prohibited.  *note PROTOCOL_TLS: 3683,
     *note PROTOCOL_TLS_CLIENT: 879, and *note PROTOCOL_TLS_SERVER: 87a.
     use TLS 1.2 as minimum TLS version.

          Note: ‘SSLContext’ only supports limited mutation once it has
          been used by a connection.  Adding new certificates to the
          internal trust store is allowed, but changing ciphers,
          verification settings, or mTLS certificates may result in
          surprising behavior.

          Note: ‘SSLContext’ is designed to be shared and used by
          multiple connections.  Thus, it is thread-safe as long as it
          is not reconfigured after being used by a connection.

*note SSLContext: 294. objects have the following methods and
attributes:

 -- Method: SSLContext.cert_store_stats ()

     Get statistics about quantities of loaded X.509 certificates, count
     of X.509 certificates flagged as CA certificates and certificate
     revocation lists as dictionary.

     Example for a context with one CA cert and one other cert:

          >>> context.cert_store_stats()
          {'crl': 0, 'x509_ca': 1, 'x509': 2}

     Added in version 3.4.

 -- Method: SSLContext.load_cert_chain (certfile, keyfile=None,
          password=None)

     Load a private key and the corresponding certificate.  The
     'certfile' string must be the path to a single file in PEM format
     containing the certificate as well as any number of CA certificates
     needed to establish the certificate’s authenticity.  The 'keyfile'
     string, if present, must point to a file containing the private
     key.  Otherwise the private key will be taken from 'certfile' as
     well.  See the discussion of *note Certificates: 36c2. for more
     information on how the certificate is stored in the 'certfile'.

     The 'password' argument may be a function to call to get the
     password for decrypting the private key.  It will only be called if
     the private key is encrypted and a password is necessary.  It will
     be called with no arguments, and it should return a string, bytes,
     or bytearray.  If the return value is a string it will be encoded
     as UTF-8 before using it to decrypt the key.  Alternatively a
     string, bytes, or bytearray value may be supplied directly as the
     'password' argument.  It will be ignored if the private key is not
     encrypted and no password is needed.

     If the 'password' argument is not specified and a password is
     required, OpenSSL’s built-in password prompting mechanism will be
     used to interactively prompt the user for a password.

     An *note SSLError: 12c0. is raised if the private key doesn’t match
     with the certificate.

     Changed in version 3.3: New optional argument 'password'.

 -- Method: SSLContext.load_default_certs (purpose=Purpose.SERVER_AUTH)

     Load a set of default “certification authority” (CA) certificates
     from default locations.  On Windows it loads CA certs from the ‘CA’
     and ‘ROOT’ system stores.  On all systems it calls *note
     SSLContext.set_default_verify_paths(): fe4.  In the future the
     method may load CA certificates from other locations, too.

     The 'purpose' flag specifies what kind of CA certificates are
     loaded.  The default settings *note Purpose.SERVER_AUTH: fec. loads
     certificates, that are flagged and trusted for TLS web server
     authentication (client side sockets).  *note Purpose.CLIENT_AUTH:
     fed. loads CA certificates for client certificate verification on
     the server side.

     Added in version 3.4.

 -- Method: SSLContext.load_verify_locations (cafile=None, capath=None,
          cadata=None)

     Load a set of “certification authority” (CA) certificates used to
     validate other peers’ certificates when *note verify_mode: 3680. is
     other than *note CERT_NONE: 3692.  At least one of 'cafile' or
     'capath' must be specified.

     This method can also load certification revocation lists (CRLs) in
     PEM or DER format.  In order to make use of CRLs, *note
     SSLContext.verify_flags: fe7. must be configured properly.

     The 'cafile' string, if present, is the path to a file of
     concatenated CA certificates in PEM format.  See the discussion of
     *note Certificates: 36c2. for more information about how to arrange
     the certificates in this file.

     The 'capath' string, if present, is the path to a directory
     containing several CA certificates in PEM format, following an
     OpenSSL specific layout(7).

     The 'cadata' object, if present, is either an ASCII string of one
     or more PEM-encoded certificates or a *note bytes-like object: d55.
     of DER-encoded certificates.  Like with 'capath' extra lines around
     PEM-encoded certificates are ignored but at least one certificate
     must be present.

     Changed in version 3.4: New optional argument 'cadata'

 -- Method: SSLContext.get_ca_certs (binary_form=False)

     Get a list of loaded “certification authority” (CA) certificates.
     If the ‘binary_form’ parameter is *note False: b4f. each list entry
     is a dict like the output of *note SSLSocket.getpeercert(): ff1.
     Otherwise the method returns a list of DER-encoded certificates.
     The returned list does not contain certificates from 'capath'
     unless a certificate was requested and loaded by a SSL connection.

          Note: Certificates in a capath directory aren’t loaded unless
          they have been used at least once.

     Added in version 3.4.

 -- Method: SSLContext.get_ciphers ()

     Get a list of enabled ciphers.  The list is in order of cipher
     priority.  See *note SSLContext.set_ciphers(): 36c3.

     Example:

          >>> ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
          >>> ctx.set_ciphers('ECDHE+AESGCM:!ECDSA')
          >>> ctx.get_ciphers()
          [{'aead': True,
            'alg_bits': 256,
            'auth': 'auth-rsa',
            'description': 'ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH     Au=RSA  '
                           'Enc=AESGCM(256) Mac=AEAD',
            'digest': None,
            'id': 50380848,
            'kea': 'kx-ecdhe',
            'name': 'ECDHE-RSA-AES256-GCM-SHA384',
            'protocol': 'TLSv1.2',
            'strength_bits': 256,
            'symmetric': 'aes-256-gcm'},
           {'aead': True,
            'alg_bits': 128,
            'auth': 'auth-rsa',
            'description': 'ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH     Au=RSA  '
                           'Enc=AESGCM(128) Mac=AEAD',
            'digest': None,
            'id': 50380847,
            'kea': 'kx-ecdhe',
            'name': 'ECDHE-RSA-AES128-GCM-SHA256',
            'protocol': 'TLSv1.2',
            'strength_bits': 128,
            'symmetric': 'aes-128-gcm'}]

     Added in version 3.6.

 -- Method: SSLContext.set_default_verify_paths ()

     Load a set of default “certification authority” (CA) certificates
     from a filesystem path defined when building the OpenSSL library.
     Unfortunately, there’s no easy way to know whether this method
     succeeds: no error is returned if no certificates are to be found.
     When the OpenSSL library is provided as part of the operating
     system, though, it is likely to be configured properly.

 -- Method: SSLContext.set_ciphers (ciphers, /)

     Set the available ciphers for sockets created with this context.
     It should be a string in the OpenSSL cipher list format(8).  If no
     cipher can be selected (because compile-time options or other
     configuration forbids use of all the specified ciphers), an *note
     SSLError: 12c0. will be raised.

          Note: when connected, the *note SSLSocket.cipher(): 35aa.
          method of SSL sockets will give the currently selected cipher.

          TLS 1.3 cipher suites cannot be disabled with ‘set_ciphers()’.

 -- Method: SSLContext.set_alpn_protocols (alpn_protocols)

     Specify which protocols the socket should advertise during the
     SSL/TLS handshake.  It should be a list of ASCII strings, like
     ‘['http/1.1', 'spdy/2']’, ordered by preference.  The selection of
     a protocol will happen during the handshake, and will play out
     according to RFC 7301(9).  After a successful handshake, the *note
     SSLSocket.selected_alpn_protocol(): e99. method will return the
     agreed-upon protocol.

     This method will raise *note NotImplementedError: 228. if *note
     HAS_ALPN: e9a. is ‘False’.

     Added in version 3.5.

 -- Method: SSLContext.set_npn_protocols (npn_protocols)

     Specify which protocols the socket should advertise during the
     SSL/TLS handshake.  It should be a list of strings, like
     ‘['http/1.1', 'spdy/2']’, ordered by preference.  The selection of
     a protocol will happen during the handshake, and will play out
     according to the Application Layer Protocol Negotiation(10).  After
     a successful handshake, the *note
     SSLSocket.selected_npn_protocol(): 87b. method will return the
     agreed-upon protocol.

     This method will raise *note NotImplementedError: 228. if *note
     HAS_NPN: 36a7. is ‘False’.

     Added in version 3.3.

     Deprecated since version 3.10: NPN has been superseded by ALPN

 -- Attribute: SSLContext.sni_callback

     Register a callback function that will be called after the TLS
     Client Hello handshake message has been received by the SSL/TLS
     server when the TLS client specifies a server name indication.  The
     server name indication mechanism is specified in RFC 6066(11)
     section 3 - Server Name Indication.

     Only one callback can be set per ‘SSLContext’.  If 'sni_callback'
     is set to ‘None’ then the callback is disabled.  Calling this
     function a subsequent time will disable the previously registered
     callback.

     The callback function will be called with three arguments; the
     first being the *note ssl.SSLSocket: 8f3, the second is a string
     that represents the server name that the client is intending to
     communicate (or *note None: 678. if the TLS Client Hello does not
     contain a server name) and the third argument is the original *note
     SSLContext: 294.  The server name argument is text.  For
     internationalized domain name, the server name is an IDN A-label
     (‘"xn--pythn-mua.org"’).

     A typical use of this callback is to change the *note
     ssl.SSLSocket: 8f3.’s *note SSLSocket.context: 36bd. attribute to a
     new object of type *note SSLContext: 294. representing a
     certificate chain that matches the server name.

     Due to the early negotiation phase of the TLS connection, only
     limited methods and attributes are usable like *note
     SSLSocket.selected_alpn_protocol(): e99. and *note
     SSLSocket.context: 36bd.  The *note SSLSocket.getpeercert(): ff1,
     *note SSLSocket.get_verified_chain(): 16e4, *note
     SSLSocket.get_unverified_chain(): 16e5. *note SSLSocket.cipher():
     35aa. and *note SSLSocket.compression(): 1189. methods require that
     the TLS connection has progressed beyond the TLS Client Hello and
     therefore will not return meaningful values nor can they be called
     safely.

     The 'sni_callback' function must return ‘None’ to allow the TLS
     negotiation to continue.  If a TLS failure is required, a constant
     *note ALERT_DESCRIPTION_*: 36b0. can be returned.  Other return
     values will result in a TLS fatal error with
     ‘ALERT_DESCRIPTION_INTERNAL_ERROR’.

     If an exception is raised from the 'sni_callback' function the TLS
     connection will terminate with a fatal TLS alert message *note
     ALERT_DESCRIPTION_HANDSHAKE_FAILURE: 36af.

     This method will raise *note NotImplementedError: 228. if the
     OpenSSL library had OPENSSL_NO_TLSEXT defined when it was built.

     Added in version 3.7.

 -- Method: SSLContext.set_servername_callback (server_name_callback)

     This is a legacy API retained for backwards compatibility.  When
     possible, you should use *note sni_callback: 1a35. instead.  The
     given 'server_name_callback' is similar to 'sni_callback', except
     that when the server hostname is an IDN-encoded internationalized
     domain name, the 'server_name_callback' receives a decoded U-label
     (‘"pythön.org"’).

     If there is a decoding error on the server name, the TLS connection
     will terminate with an *note ALERT_DESCRIPTION_INTERNAL_ERROR:
     36b0. fatal TLS alert message to the client.

     Added in version 3.4.

 -- Method: SSLContext.load_dh_params (dhfile, /)

     Load the key generation parameters for Diffie-Hellman (DH) key
     exchange.  Using DH key exchange improves forward secrecy at the
     expense of computational resources (both on the server and on the
     client).  The 'dhfile' parameter should be the path to a file
     containing DH parameters in PEM format.

     This setting doesn’t apply to client sockets.  You can also use the
     *note OP_SINGLE_DH_USE: 369f. option to further improve security.

     Added in version 3.3.

 -- Method: SSLContext.set_ecdh_curve (curve_name, /)

     Set the curve name for Elliptic Curve-based Diffie-Hellman (ECDH)
     key exchange.  ECDH is significantly faster than regular DH while
     arguably as secure.  The 'curve_name' parameter should be a string
     describing a well-known elliptic curve, for example ‘prime256v1’
     for a widely supported curve.

     This setting doesn’t apply to client sockets.  You can also use the
     *note OP_SINGLE_ECDH_USE: 36a0. option to further improve security.

     This method is not available if *note HAS_ECDH: 36a5. is ‘False’.

     Added in version 3.3.

     See also
     ........

     SSL/TLS & Perfect Forward Secrecy(12)

          Vincent Bernat.

 -- Method: SSLContext.wrap_socket (sock, server_side=False,
          do_handshake_on_connect=True, suppress_ragged_eofs=True,
          server_hostname=None, session=None)

     Wrap an existing Python socket 'sock' and return an instance of
     *note SSLContext.sslsocket_class: 36c4. (default *note SSLSocket:
     8f3.).  The returned SSL socket is tied to the context, its
     settings and certificates.  'sock' must be a *note SOCK_STREAM:
     133c. socket; other socket types are unsupported.

     The parameter ‘server_side’ is a boolean which identifies whether
     server-side or client-side behavior is desired from this socket.

     For client-side sockets, the context construction is lazy; if the
     underlying socket isn’t connected yet, the context construction
     will be performed after ‘connect()’ is called on the socket.  For
     server-side sockets, if the socket has no remote peer, it is
     assumed to be a listening socket, and the server-side SSL wrapping
     is automatically performed on client connections accepted via the
     ‘accept()’ method.  The method may raise *note SSLError: 12c0.

     On client connections, the optional parameter 'server_hostname'
     specifies the hostname of the service which we are connecting to.
     This allows a single server to host multiple SSL-based services
     with distinct certificates, quite similarly to HTTP virtual hosts.
     Specifying 'server_hostname' will raise a *note ValueError: 202. if
     'server_side' is true.

     The parameter ‘do_handshake_on_connect’ specifies whether to do the
     SSL handshake automatically after doing a ‘socket.connect()’, or
     whether the application program will call it explicitly, by
     invoking the *note SSLSocket.do_handshake(): ea1. method.  Calling
     ‘SSLSocket.do_handshake()’ explicitly gives the program control
     over the blocking behavior of the socket I/O involved in the
     handshake.

     The parameter ‘suppress_ragged_eofs’ specifies how the
     ‘SSLSocket.recv()’ method should signal unexpected EOF from the
     other end of the connection.  If specified as *note True: c2d. (the
     default), it returns a normal EOF (an empty bytes object) in
     response to unexpected EOF errors raised from the underlying
     socket; if *note False: b4f, it will raise the exceptions back to
     the caller.

     'session', see *note session: 16b1.

     To wrap an *note SSLSocket: 8f3. in another ‘SSLSocket’, use *note
     SSLContext.wrap_bio(): ba0.

     Changed in version 3.5: Always allow a server_hostname to be
     passed, even if OpenSSL does not have SNI.

     Changed in version 3.6: 'session' argument was added.

     Changed in version 3.7: The method returns an instance of *note
     SSLContext.sslsocket_class: 36c4. instead of hard-coded *note
     SSLSocket: 8f3.

 -- Attribute: SSLContext.sslsocket_class

     The return type of *note SSLContext.wrap_socket(): 528, defaults to
     *note SSLSocket: 8f3.  The attribute can be assigned to on
     instances of *note SSLContext: 294. in order to return a custom
     subclass of ‘SSLSocket’.

     Added in version 3.7.

 -- Method: SSLContext.wrap_bio (incoming, outgoing, server_side=False,
          server_hostname=None, session=None)

     Wrap the BIO objects 'incoming' and 'outgoing' and return an
     instance of *note SSLContext.sslobject_class: 36c5. (default *note
     SSLObject: b9f.).  The SSL routines will read input data from the
     incoming BIO and write data to the outgoing BIO.

     The 'server_side', 'server_hostname' and 'session' parameters have
     the same meaning as in *note SSLContext.wrap_socket(): 528.

     Changed in version 3.6: 'session' argument was added.

     Changed in version 3.7: The method returns an instance of *note
     SSLContext.sslobject_class: 36c5. instead of hard-coded *note
     SSLObject: b9f.

 -- Attribute: SSLContext.sslobject_class

     The return type of *note SSLContext.wrap_bio(): ba0, defaults to
     *note SSLObject: b9f.  The attribute can be overridden on instance
     of class in order to return a custom subclass of ‘SSLObject’.

     Added in version 3.7.

 -- Method: SSLContext.session_stats ()

     Get statistics about the SSL sessions created or managed by this
     context.  A dictionary is returned which maps the names of each
     piece of information(13) to their numeric values.  For example,
     here is the total number of hits and misses in the session cache
     since the context was created:

          >>> stats = context.session_stats()
          >>> stats['hits'], stats['misses']
          (0, 0)

 -- Attribute: SSLContext.check_hostname

     Whether to match the peer cert’s hostname in *note
     SSLSocket.do_handshake(): ea1.  The context’s *note verify_mode:
     3680. must be set to *note CERT_OPTIONAL: 3693. or *note
     CERT_REQUIRED: 3681, and you must pass 'server_hostname' to *note
     wrap_socket(): 528. in order to match the hostname.  Enabling
     hostname checking automatically sets ‘verify_mode’ from *note
     CERT_NONE: 3692. to ‘CERT_REQUIRED’.  It cannot be set back to
     ‘CERT_NONE’ as long as hostname checking is enabled.  The *note
     PROTOCOL_TLS_CLIENT: 879. protocol enables hostname checking by
     default.  With other protocols, hostname checking must be enabled
     explicitly.

     Example:

          import socket, ssl

          context = ssl.SSLContext(ssl.PROTOCOL_TLSv1_2)
          context.verify_mode = ssl.CERT_REQUIRED
          context.check_hostname = True
          context.load_default_certs()

          s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
          ssl_sock = context.wrap_socket(s, server_hostname='www.verisign.com')
          ssl_sock.connect(('www.verisign.com', 443))

     Added in version 3.4.

     Changed in version 3.7: *note verify_mode: 3680. is now
     automatically changed to *note CERT_REQUIRED: 3681. when hostname
     checking is enabled and ‘verify_mode’ is *note CERT_NONE: 3692.
     Previously the same operation would have failed with a *note
     ValueError: 202.

 -- Attribute: SSLContext.keylog_filename

     Write TLS keys to a keylog file, whenever key material is generated
     or received.  The keylog file is designed for debugging purposes
     only.  The file format is specified by NSS and used by many traffic
     analyzers such as Wireshark.  The log file is opened in append-only
     mode.  Writes are synchronized between threads, but not between
     processes.

     Added in version 3.8.

 -- Attribute: SSLContext.maximum_version

     A *note TLSVersion: 36b3. enum member representing the highest
     supported TLS version.  The value defaults to *note
     TLSVersion.MAXIMUM_SUPPORTED: 36b5.  The attribute is read-only for
     protocols other than *note PROTOCOL_TLS: 3683, *note
     PROTOCOL_TLS_CLIENT: 879, and *note PROTOCOL_TLS_SERVER: 87a.

     The attributes ‘maximum_version’, *note minimum_version: 877. and
     *note SSLContext.options: 83e. all affect the supported SSL and TLS
     versions of the context.  The implementation does not prevent
     invalid combination.  For example a context with *note
     OP_NO_TLSv1_2: 369d. in ‘options’ and ‘maximum_version’ set to
     *note TLSVersion.TLSv1_2: 36b9. will not be able to establish a TLS
     1.2 connection.

     Added in version 3.7.

 -- Attribute: SSLContext.minimum_version

     Like *note SSLContext.maximum_version: 878. except it is the lowest
     supported version or *note TLSVersion.MINIMUM_SUPPORTED: 36b4.

     Added in version 3.7.

 -- Attribute: SSLContext.num_tickets

     Control the number of TLS 1.3 session tickets of a *note
     PROTOCOL_TLS_SERVER: 87a. context.  The setting has no impact on
     TLS 1.0 to 1.2 connections.

     Added in version 3.8.

 -- Attribute: SSLContext.options

     An integer representing the set of SSL options enabled on this
     context.  The default value is *note OP_ALL: 369a, but you can
     specify other options such as *note OP_NO_SSLv2: 83f. by ORing them
     together.

     Changed in version 3.6: ‘SSLContext.options’ returns *note Options:
     36a2. flags:

          >>> ssl.create_default_context().options
          <Options.OP_ALL|OP_NO_SSLv3|OP_NO_SSLv2|OP_NO_COMPRESSION: 2197947391>

     Deprecated since version 3.7: All ‘OP_NO_SSL*’ and ‘OP_NO_TLS*’
     options have been deprecated since Python 3.7.  Use *note
     SSLContext.minimum_version: 877. and *note
     SSLContext.maximum_version: 878. instead.

 -- Attribute: SSLContext.post_handshake_auth

     Enable TLS 1.3 post-handshake client authentication.
     Post-handshake auth is disabled by default and a server can only
     request a TLS client certificate during the initial handshake.
     When enabled, a server may request a TLS client certificate at any
     time after the handshake.

     When enabled on client-side sockets, the client signals the server
     that it supports post-handshake authentication.

     When enabled on server-side sockets, *note SSLContext.verify_mode:
     3680. must be set to *note CERT_OPTIONAL: 3693. or *note
     CERT_REQUIRED: 3681, too.  The actual client cert exchange is
     delayed until *note SSLSocket.verify_client_post_handshake(): a3f.
     is called and some I/O is performed.

     Added in version 3.8.

 -- Attribute: SSLContext.protocol

     The protocol version chosen when constructing the context.  This
     attribute is read-only.

 -- Attribute: SSLContext.hostname_checks_common_name

     Whether *note check_hostname: 3694. falls back to verify the cert’s
     subject common name in the absence of a subject alternative name
     extension (default: true).

     Added in version 3.7.

     Changed in version 3.10: The flag had no effect with OpenSSL before
     version 1.1.1l.  Python 3.8.9, 3.9.3, and 3.10 include workarounds
     for previous versions.

 -- Attribute: SSLContext.security_level

     An integer representing the security level(14) for the context.
     This attribute is read-only.

     Added in version 3.10.

 -- Attribute: SSLContext.verify_flags

     The flags for certificate verification operations.  You can set
     flags like *note VERIFY_CRL_CHECK_LEAF: fe9. by ORing them
     together.  By default OpenSSL does neither require nor verify
     certificate revocation lists (CRLs).

     Added in version 3.4.

     Changed in version 3.6: ‘SSLContext.verify_flags’ returns *note
     VerifyFlags: 3697. flags:

          >>> ssl.create_default_context().verify_flags
          <VerifyFlags.VERIFY_X509_TRUSTED_FIRST: 32768>

 -- Attribute: SSLContext.verify_mode

     Whether to try to verify other peers’ certificates and how to
     behave if verification fails.  This attribute must be one of *note
     CERT_NONE: 3692, *note CERT_OPTIONAL: 3693. or *note CERT_REQUIRED:
     3681.

     Changed in version 3.6: ‘SSLContext.verify_mode’ returns *note
     VerifyMode: 3695. enum:

          >>> ssl.create_default_context().verify_mode
          <VerifyMode.CERT_REQUIRED: 2>

 -- Method: SSLContext.set_psk_client_callback (callback)

     Enables TLS-PSK (pre-shared key) authentication on a client-side
     connection.

     In general, certificate based authentication should be preferred
     over this method.

     The parameter ‘callback’ is a callable object with the signature:
     ‘def callback(hint: str | None) -> tuple[str | None, bytes]’.  The
     ‘hint’ parameter is an optional identity hint sent by the server.
     The return value is a tuple in the form (client-identity, psk).
     Client-identity is an optional string which may be used by the
     server to select a corresponding PSK for the client.  The string
     must be less than or equal to ‘256’ octets when UTF-8 encoded.  PSK
     is a *note bytes-like object: d55. representing the pre-shared key.
     Return a zero length PSK to reject the connection.

     Setting ‘callback’ to *note None: 678. removes any existing
     callback.

          Note: When using TLS 1.3:

             - the ‘hint’ parameter is always *note None: 678.

             - client-identity must be a non-empty string.

     Example usage:

          context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
          context.check_hostname = False
          context.verify_mode = ssl.CERT_NONE
          context.maximum_version = ssl.TLSVersion.TLSv1_2
          context.set_ciphers('PSK')

          # A simple lambda:
          psk = bytes.fromhex('c0ffee')
          context.set_psk_client_callback(lambda hint: (None, psk))

          # A table using the hint from the server:
          psk_table = { 'ServerId_1': bytes.fromhex('c0ffee'),
                        'ServerId_2': bytes.fromhex('facade')
          }
          def callback(hint):
              return 'ClientId_1', psk_table.get(hint, b'')
          context.set_psk_client_callback(callback)

     This method will raise *note NotImplementedError: 228. if *note
     HAS_PSK: 36ad. is ‘False’.

     Added in version 3.13.

 -- Method: SSLContext.set_psk_server_callback (callback,
          identity_hint=None)

     Enables TLS-PSK (pre-shared key) authentication on a server-side
     connection.

     In general, certificate based authentication should be preferred
     over this method.

     The parameter ‘callback’ is a callable object with the signature:
     ‘def callback(identity: str | None) -> bytes’.  The ‘identity’
     parameter is an optional identity sent by the client which can be
     used to select a corresponding PSK. The return value is a *note
     bytes-like object: d55. representing the pre-shared key.  Return a
     zero length PSK to reject the connection.

     Setting ‘callback’ to *note None: 678. removes any existing
     callback.

     The parameter ‘identity_hint’ is an optional identity hint string
     sent to the client.  The string must be less than or equal to ‘256’
     octets when UTF-8 encoded.

          Note: When using TLS 1.3 the ‘identity_hint’ parameter is not
          sent to the client.

     Example usage:

          context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
          context.maximum_version = ssl.TLSVersion.TLSv1_2
          context.set_ciphers('PSK')

          # A simple lambda:
          psk = bytes.fromhex('c0ffee')
          context.set_psk_server_callback(lambda identity: psk)

          # A table using the identity of the client:
          psk_table = { 'ClientId_1': bytes.fromhex('c0ffee'),
                        'ClientId_2': bytes.fromhex('facade')
          }
          def callback(identity):
              return psk_table.get(identity, b'')
          context.set_psk_server_callback(callback, 'ServerId_1')

     This method will raise *note NotImplementedError: 228. if *note
     HAS_PSK: 36ad. is ‘False’.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) TLS 1.3 protocol will be available with *note PROTOCOL_TLS: 3683.
in OpenSSL >= 1.1.1.  There is no dedicated PROTOCOL constant for just
TLS 1.3.

   (2) ‘SSLContext’ disables SSLv2 with *note OP_NO_SSLv2: 83f. by
default.

   (3) ‘SSLContext’ disables SSLv3 with *note OP_NO_SSLv3: 840. by
default.

   (4) TLS 1.3 protocol will be available with *note PROTOCOL_TLS: 3683.
in OpenSSL >= 1.1.1.  There is no dedicated PROTOCOL constant for just
TLS 1.3.

   (5) ‘SSLContext’ disables SSLv2 with *note OP_NO_SSLv2: 83f. by
default.

   (6) ‘SSLContext’ disables SSLv3 with *note OP_NO_SSLv3: 840. by
default.

   (7) 
https://docs.openssl.org/master/man3/SSL_CTX_load_verify_locations/

   (8) https://docs.openssl.org/master/man1/ciphers/

   (9) https://datatracker.ietf.org/doc/html/rfc7301.html

   (10) 
https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation

   (11) https://datatracker.ietf.org/doc/html/rfc6066.html

   (12) 
https://vincent.bernat.ch/en/blog/2011-ssl-perfect-forward-secrecy

   (13) https://docs.openssl.org/1.1.1/man3/SSL_CTX_sess_number/

   (14) https://docs.openssl.org/master/man3/SSL_CTX_get_security_level/


File: python.info,  Node: Certificates,  Next: Examples<20>,  Prev: SSL contexts,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.10 Certificates
......................

Certificates in general are part of a public-key / private-key system.
In this system, each 'principal', (which may be a machine, or a person,
or an organization) is assigned a unique two-part encryption key.  One
part of the key is public, and is called the 'public key'; the other
part is kept secret, and is called the 'private key'.  The two parts are
related, in that if you encrypt a message with one of the parts, you can
decrypt it with the other part, and 'only' with the other part.

A certificate contains information about two principals.  It contains
the name of a 'subject', and the subject’s public key.  It also contains
a statement by a second principal, the 'issuer', that the subject is who
they claim to be, and that this is indeed the subject’s public key.  The
issuer’s statement is signed with the issuer’s private key, which only
the issuer knows.  However, anyone can verify the issuer’s statement by
finding the issuer’s public key, decrypting the statement with it, and
comparing it to the other information in the certificate.  The
certificate also contains information about the time period over which
it is valid.  This is expressed as two fields, called “notBefore” and
“notAfter”.

In the Python use of certificates, a client or server can use a
certificate to prove who they are.  The other side of a network
connection can also be required to produce a certificate, and that
certificate can be validated to the satisfaction of the client or server
that requires such validation.  The connection attempt can be set to
raise an exception if the validation fails.  Validation is done
automatically, by the underlying OpenSSL framework; the application need
not concern itself with its mechanics.  But the application does usually
need to provide sets of certificates to allow this process to take
place.

Python uses files to contain certificates.  They should be formatted as
“PEM” (see RFC 1422(1)), which is a base-64 encoded form wrapped with a
header line and a footer line:

     -----BEGIN CERTIFICATE-----
     ... (certificate in base64 PEM encoding) ...
     -----END CERTIFICATE-----

* Menu:

* Certificate chains::
* CA certificates::
* Combined key and certificate::
* Self-signed certificates::

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc1422.html


File: python.info,  Node: Certificate chains,  Next: CA certificates,  Up: Certificates

5.19.3.11 Certificate chains
............................

The Python files which contain certificates can contain a sequence of
certificates, sometimes called a 'certificate chain'.  This chain should
start with the specific certificate for the principal who “is” the
client or server, and then the certificate for the issuer of that
certificate, and then the certificate for the issuer of 'that'
certificate, and so on up the chain till you get to a certificate which
is 'self-signed', that is, a certificate which has the same subject and
issuer, sometimes called a 'root certificate'.  The certificates should
just be concatenated together in the certificate file.  For example,
suppose we had a three certificate chain, from our server certificate to
the certificate of the certification authority that signed our server
certificate, to the root certificate of the agency which issued the
certification authority’s certificate:

     -----BEGIN CERTIFICATE-----
     ... (certificate for your server)...
     -----END CERTIFICATE-----
     -----BEGIN CERTIFICATE-----
     ... (the certificate for the CA)...
     -----END CERTIFICATE-----
     -----BEGIN CERTIFICATE-----
     ... (the root certificate for the CA's issuer)...
     -----END CERTIFICATE-----


File: python.info,  Node: CA certificates,  Next: Combined key and certificate,  Prev: Certificate chains,  Up: Certificates

5.19.3.12 CA certificates
.........................

If you are going to require validation of the other side of the
connection’s certificate, you need to provide a “CA certs” file, filled
with the certificate chains for each issuer you are willing to trust.
Again, this file just contains these chains concatenated together.  For
validation, Python will use the first chain it finds in the file which
matches.  The platform’s certificates file can be used by calling *note
SSLContext.load_default_certs(): feb, this is done automatically with
*note create_default_context(): 155.


File: python.info,  Node: Combined key and certificate,  Next: Self-signed certificates,  Prev: CA certificates,  Up: Certificates

5.19.3.13 Combined key and certificate
......................................

Often the private key is stored in the same file as the certificate; in
this case, only the ‘certfile’ parameter to *note
SSLContext.load_cert_chain(): 295. needs to be passed.  If the private
key is stored with the certificate, it should come before the first
certificate in the certificate chain:

     -----BEGIN RSA PRIVATE KEY-----
     ... (private key in base64 encoding) ...
     -----END RSA PRIVATE KEY-----
     -----BEGIN CERTIFICATE-----
     ... (certificate in base64 PEM encoding) ...
     -----END CERTIFICATE-----


File: python.info,  Node: Self-signed certificates,  Prev: Combined key and certificate,  Up: Certificates

5.19.3.14 Self-signed certificates
..................................

If you are going to create a server that provides SSL-encrypted
connection services, you will need to acquire a certificate for that
service.  There are many ways of acquiring appropriate certificates,
such as buying one from a certification authority.  Another common
practice is to generate a self-signed certificate.  The simplest way to
do this is with the OpenSSL package, using something like the following:

     % openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout cert.pem
     Generating a 1024 bit RSA private key
     .......++++++
     .............................++++++
     writing new private key to 'cert.pem'
     -----
     You are about to be asked to enter information that will be incorporated
     into your certificate request.
     What you are about to enter is what is called a Distinguished Name or a DN.
     There are quite a few fields but you can leave some blank
     For some fields there will be a default value,
     If you enter '.', the field will be left blank.
     -----
     Country Name (2 letter code) [AU]:US
     State or Province Name (full name) [Some-State]:MyState
     Locality Name (eg, city) []:Some City
     Organization Name (eg, company) [Internet Widgits Pty Ltd]:My Organization, Inc.
     Organizational Unit Name (eg, section) []:My Group
     Common Name (eg, YOUR name) []:myserver.mygroup.myorganization.com
     Email Address []:ops@myserver.mygroup.myorganization.com
     %

The disadvantage of a self-signed certificate is that it is its own root
certificate, and no one else will have it in their cache of known (and
trusted) root certificates.


File: python.info,  Node: Examples<20>,  Next: Notes on non-blocking sockets,  Prev: Certificates,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.15 Examples
..................

* Menu:

* Testing for SSL support::
* Client-side operation::
* Server-side operation::


File: python.info,  Node: Testing for SSL support,  Next: Client-side operation,  Up: Examples<20>

5.19.3.16 Testing for SSL support
.................................

To test for the presence of SSL support in a Python installation, user
code should use the following idiom:

     try:
         import ssl
     except ImportError:
         pass
     else:
         ...  # do something that requires SSL support


File: python.info,  Node: Client-side operation,  Next: Server-side operation,  Prev: Testing for SSL support,  Up: Examples<20>

5.19.3.17 Client-side operation
...............................

This example creates a SSL context with the recommended security
settings for client sockets, including automatic certificate
verification:

     >>> context = ssl.create_default_context()

If you prefer to tune security settings yourself, you might create a
context from scratch (but beware that you might not get the settings
right):

     >>> context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
     >>> context.load_verify_locations("/etc/ssl/certs/ca-bundle.crt")

(this snippet assumes your operating system places a bundle of all CA
certificates in ‘/etc/ssl/certs/ca-bundle.crt’; if not, you’ll get an
error and have to adjust the location)

The *note PROTOCOL_TLS_CLIENT: 879. protocol configures the context for
cert validation and hostname verification.  *note verify_mode: 3680. is
set to *note CERT_REQUIRED: 3681. and *note check_hostname: 3694. is set
to ‘True’.  All other protocols create SSL contexts with insecure
defaults.

When you use the context to connect to a server, *note CERT_REQUIRED:
3681. and *note check_hostname: 3694. validate the server certificate:
it ensures that the server certificate was signed with one of the CA
certificates, checks the signature for correctness, and verifies other
properties like validity and identity of the hostname:

     >>> conn = context.wrap_socket(socket.socket(socket.AF_INET),
     ...                            server_hostname="www.python.org")
     >>> conn.connect(("www.python.org", 443))

You may then fetch the certificate:

     >>> cert = conn.getpeercert()

Visual inspection shows that the certificate does identify the desired
service (that is, the HTTPS host ‘www.python.org’):

     >>> pprint.pprint(cert)
     {'OCSP': ('http://ocsp.digicert.com',),
      'caIssuers': ('http://cacerts.digicert.com/DigiCertSHA2ExtendedValidationServerCA.crt',),
      'crlDistributionPoints': ('http://crl3.digicert.com/sha2-ev-server-g1.crl',
                                'http://crl4.digicert.com/sha2-ev-server-g1.crl'),
      'issuer': ((('countryName', 'US'),),
                 (('organizationName', 'DigiCert Inc'),),
                 (('organizationalUnitName', 'www.digicert.com'),),
                 (('commonName', 'DigiCert SHA2 Extended Validation Server CA'),)),
      'notAfter': 'Sep  9 12:00:00 2016 GMT',
      'notBefore': 'Sep  5 00:00:00 2014 GMT',
      'serialNumber': '01BB6F00122B177F36CAB49CEA8B6B26',
      'subject': ((('businessCategory', 'Private Organization'),),
                  (('1.3.6.1.4.1.311.60.2.1.3', 'US'),),
                  (('1.3.6.1.4.1.311.60.2.1.2', 'Delaware'),),
                  (('serialNumber', '3359300'),),
                  (('streetAddress', '16 Allen Rd'),),
                  (('postalCode', '03894-4801'),),
                  (('countryName', 'US'),),
                  (('stateOrProvinceName', 'NH'),),
                  (('localityName', 'Wolfeboro'),),
                  (('organizationName', 'Python Software Foundation'),),
                  (('commonName', 'www.python.org'),)),
      'subjectAltName': (('DNS', 'www.python.org'),
                         ('DNS', 'python.org'),
                         ('DNS', 'pypi.org'),
                         ('DNS', 'docs.python.org'),
                         ('DNS', 'testpypi.org'),
                         ('DNS', 'bugs.python.org'),
                         ('DNS', 'wiki.python.org'),
                         ('DNS', 'hg.python.org'),
                         ('DNS', 'mail.python.org'),
                         ('DNS', 'packaging.python.org'),
                         ('DNS', 'pythonhosted.org'),
                         ('DNS', 'www.pythonhosted.org'),
                         ('DNS', 'test.pythonhosted.org'),
                         ('DNS', 'us.pycon.org'),
                         ('DNS', 'id.python.org')),
      'version': 3}

Now the SSL channel is established and the certificate verified, you can
proceed to talk with the server:

     >>> conn.sendall(b"HEAD / HTTP/1.0\r\nHost: linuxfr.org\r\n\r\n")
     >>> pprint.pprint(conn.recv(1024).split(b"\r\n"))
     [b'HTTP/1.1 200 OK',
      b'Date: Sat, 18 Oct 2014 18:27:20 GMT',
      b'Server: nginx',
      b'Content-Type: text/html; charset=utf-8',
      b'X-Frame-Options: SAMEORIGIN',
      b'Content-Length: 45679',
      b'Accept-Ranges: bytes',
      b'Via: 1.1 varnish',
      b'Age: 2188',
      b'X-Served-By: cache-lcy1134-LCY',
      b'X-Cache: HIT',
      b'X-Cache-Hits: 11',
      b'Vary: Cookie',
      b'Strict-Transport-Security: max-age=63072000; includeSubDomains',
      b'Connection: close',
      b'',
      b'']

See the discussion of *note Security considerations: 3564. below.


File: python.info,  Node: Server-side operation,  Prev: Client-side operation,  Up: Examples<20>

5.19.3.18 Server-side operation
...............................

For server operation, typically you’ll need to have a server
certificate, and private key, each in a file.  You’ll first create a
context holding the key and the certificate, so that clients can check
your authenticity.  Then you’ll open a socket, bind it to a port, call
‘listen()’ on it, and start waiting for clients to connect:

     import socket, ssl

     context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
     context.load_cert_chain(certfile="mycertfile", keyfile="mykeyfile")

     bindsocket = socket.socket()
     bindsocket.bind(('myaddr.example.com', 10023))
     bindsocket.listen(5)

When a client connects, you’ll call ‘accept()’ on the socket to get the
new socket from the other end, and use the context’s *note
SSLContext.wrap_socket(): 528. method to create a server-side SSL socket
for the connection:

     while True:
         newsocket, fromaddr = bindsocket.accept()
         connstream = context.wrap_socket(newsocket, server_side=True)
         try:
             deal_with_client(connstream)
         finally:
             connstream.shutdown(socket.SHUT_RDWR)
             connstream.close()

Then you’ll read data from the ‘connstream’ and do something with it
till you are finished with the client (or the client is finished with
you):

     def deal_with_client(connstream):
         data = connstream.recv(1024)
         # empty data means the client is finished with us
         while data:
             if not do_something(connstream, data):
                 # we'll assume do_something returns False
                 # when we're finished with client
                 break
             data = connstream.recv(1024)
         # finished with client

And go back to listening for new client connections (of course, a real
server would probably handle each client connection in a separate
thread, or put the sockets in *note non-blocking mode: 3686. and use an
event loop).


File: python.info,  Node: Notes on non-blocking sockets,  Next: Memory BIO support,  Prev: Examples<20>,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.19 Notes on non-blocking sockets
.......................................

SSL sockets behave slightly different than regular sockets in
non-blocking mode.  When working with non-blocking sockets, there are
thus several things you need to be aware of:

   - Most *note SSLSocket: 8f3. methods will raise either *note
     SSLWantWriteError: e9e. or *note SSLWantReadError: e9d. instead of
     *note BlockingIOError: 1095. if an I/O operation would block.
     ‘SSLWantReadError’ will be raised if a read operation on the
     underlying socket is necessary, and ‘SSLWantWriteError’ for a write
     operation on the underlying socket.  Note that attempts to 'write'
     to an SSL socket may require 'reading' from the underlying socket
     first, and attempts to 'read' from the SSL socket may require a
     prior 'write' to the underlying socket.

     Changed in version 3.5: In earlier Python versions, the
     ‘SSLSocket.send()’ method returned zero instead of raising *note
     SSLWantWriteError: e9e. or *note SSLWantReadError: e9d.

   - Calling *note select(): dce. tells you that the OS-level socket can
     be read from (or written to), but it does not imply that there is
     sufficient data at the upper SSL layer.  For example, only part of
     an SSL frame might have arrived.  Therefore, you must be ready to
     handle ‘SSLSocket.recv()’ and ‘SSLSocket.send()’ failures, and
     retry after another call to ‘select()’.

   - Conversely, since the SSL layer has its own framing, a SSL socket
     may still have data available for reading without *note select():
     dce. being aware of it.  Therefore, you should first call
     ‘SSLSocket.recv()’ to drain any potentially available data, and
     then only block on a ‘select()’ call if still necessary.

     (of course, similar provisions apply when using other primitives
     such as *note poll(): 2da7, or those in the *note selectors: c2.
     module)

   - The SSL handshake itself will be non-blocking: the *note
     SSLSocket.do_handshake(): ea1. method has to be retried until it
     returns successfully.  Here is a synopsis using *note select():
     dce. to wait for the socket’s readiness:

          while True:
              try:
                  sock.do_handshake()
                  break
              except ssl.SSLWantReadError:
                  select.select([sock], [], [])
              except ssl.SSLWantWriteError:
                  select.select([], [sock], [])

See also
........

The *note asyncio: a. module supports *note non-blocking SSL sockets:
3686. and provides a higher level *note Streams API: 348f.  It polls for
events using the *note selectors: c2. module and handles *note
SSLWantWriteError: e9e, *note SSLWantReadError: e9d. and *note
BlockingIOError: 1095. exceptions.  It runs the SSL handshake
asynchronously as well.


File: python.info,  Node: Memory BIO support,  Next: SSL session,  Prev: Notes on non-blocking sockets,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.20 Memory BIO support
............................

Added in version 3.5.

Ever since the SSL module was introduced in Python 2.6, the *note
SSLSocket: 8f3. class has provided two related but distinct areas of
functionality:

   - SSL protocol handling

   - Network IO

The network IO API is identical to that provided by *note socket.socket:
dcf, from which *note SSLSocket: 8f3. also inherits.  This allows an SSL
socket to be used as a drop-in replacement for a regular socket, making
it very easy to add SSL support to an existing application.

Combining SSL protocol handling and network IO usually works well, but
there are some cases where it doesn’t.  An example is async IO
frameworks that want to use a different IO multiplexing model than the
“select/poll on a file descriptor” (readiness based) model that is
assumed by *note socket.socket: dcf. and by the internal OpenSSL socket
IO routines.  This is mostly relevant for platforms like Windows where
this model is not efficient.  For this purpose, a reduced scope variant
of *note SSLSocket: 8f3. called *note SSLObject: b9f. is provided.

 -- Class: ssl.SSLObject

     A reduced-scope variant of *note SSLSocket: 8f3. representing an
     SSL protocol instance that does not contain any network IO methods.
     This class is typically used by framework authors that want to
     implement asynchronous IO for SSL through memory buffers.

     This class implements an interface on top of a low-level SSL object
     as implemented by OpenSSL. This object captures the state of an SSL
     connection but does not provide any network IO itself.  IO needs to
     be performed through separate “BIO” objects which are OpenSSL’s IO
     abstraction layer.

     This class has no public constructor.  An ‘SSLObject’ instance must
     be created using the *note wrap_bio(): ba0. method.  This method
     will create the ‘SSLObject’ instance and bind it to a pair of BIOs.
     The 'incoming' BIO is used to pass data from Python to the SSL
     protocol instance, while the 'outgoing' BIO is used to pass data
     the other way around.

     The following methods are available:

        - *note context: 36bd.

        - *note server_side: 36bf.

        - *note server_hostname: b9d.

        - *note session: 16b1.

        - *note session_reused: 36c0.

        - *note read(): ea2.

        - *note write(): ea3.

        - *note getpeercert(): ff1.

        - *note get_verified_chain(): 16e4.

        - *note get_unverified_chain(): 16e5.

        - *note selected_alpn_protocol(): e99.

        - *note selected_npn_protocol(): 87b.

        - *note cipher(): 35aa.

        - *note shared_ciphers(): ea0.

        - *note compression(): 1189.

        - *note pending(): 36be.

        - *note do_handshake(): ea1.

        - *note verify_client_post_handshake(): a3f.

        - *note unwrap(): 36bc.

        - *note get_channel_binding(): 1188.

        - *note version(): e9c.

     When compared to *note SSLSocket: 8f3, this object lacks the
     following features:

        - Any form of network IO; ‘recv()’ and ‘send()’ read and write
          only to the underlying *note MemoryBIO: e96. buffers.

        - There is no 'do_handshake_on_connect' machinery.  You must
          always manually call *note do_handshake(): ea1. to start the
          handshake.

        - There is no handling of 'suppress_ragged_eofs'.  All
          end-of-file conditions that are in violation of the protocol
          are reported via the *note SSLEOFError: 185c. exception.

        - The method *note unwrap(): 36bc. call does not return
          anything, unlike for an SSL socket where it returns the
          underlying socket.

        - The 'server_name_callback' callback passed to *note
          SSLContext.set_servername_callback(): ff0. will get an
          ‘SSLObject’ instance instead of a *note SSLSocket: 8f3.
          instance as its first parameter.

     Some notes related to the use of ‘SSLObject’:

        - All IO on an ‘SSLObject’ is *note non-blocking: 3686.  This
          means that for example *note read(): ea2. will raise an *note
          SSLWantReadError: e9d. if it needs more data than the incoming
          BIO has available.

     Changed in version 3.7: ‘SSLObject’ instances must be created with
     *note wrap_bio(): ba0.  In earlier versions, it was possible to
     create instances directly.  This was never documented or officially
     supported.

An SSLObject communicates with the outside world using memory buffers.
The class *note MemoryBIO: e96. provides a memory buffer that can be
used for this purpose.  It wraps an OpenSSL memory BIO (Basic IO)
object:

 -- Class: ssl.MemoryBIO

     A memory buffer that can be used to pass data between Python and an
     SSL protocol instance.

      -- Attribute: pending

          Return the number of bytes currently in the memory buffer.

      -- Attribute: eof

          A boolean indicating whether the memory BIO is current at the
          end-of-file position.

      -- Method: read (n=-1, /)

          Read up to 'n' bytes from the memory buffer.  If 'n' is not
          specified or negative, all bytes are returned.

      -- Method: write (buf, /)

          Write the bytes from 'buf' to the memory BIO. The 'buf'
          argument must be an object supporting the buffer protocol.

          The return value is the number of bytes written, which is
          always equal to the length of 'buf'.

      -- Method: write_eof ()

          Write an EOF marker to the memory BIO. After this method has
          been called, it is illegal to call *note write(): 36da.  The
          attribute *note eof: 36d8. will become true after all data
          currently in the buffer has been read.


File: python.info,  Node: SSL session,  Next: Security considerations<2>,  Prev: Memory BIO support,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.21 SSL session
.....................

Added in version 3.6.

 -- Class: ssl.SSLSession

     Session object used by *note session: 16b1.

      -- Attribute: id

      -- Attribute: time

      -- Attribute: timeout

      -- Attribute: ticket_lifetime_hint

      -- Attribute: has_ticket


File: python.info,  Node: Security considerations<2>,  Next: TLS 1 3,  Prev: SSL session,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.22 Security considerations
.................................

* Menu:

* Best defaults::
* Manual settings::
* Multi-processing::


File: python.info,  Node: Best defaults,  Next: Manual settings,  Up: Security considerations<2>

5.19.3.23 Best defaults
.......................

For 'client use', if you don’t have any special requirements for your
security policy, it is highly recommended that you use the *note
create_default_context(): 155. function to create your SSL context.  It
will load the system’s trusted CA certificates, enable certificate
validation and hostname checking, and try to choose reasonably secure
protocol and cipher settings.

For example, here is how you would use the *note smtplib.SMTP: 937.
class to create a trusted, secure connection to a SMTP server:

     >>> import ssl, smtplib
     >>> smtp = smtplib.SMTP("mail.python.org", port=587)
     >>> context = ssl.create_default_context()
     >>> smtp.starttls(context=context)
     (220, b'2.0.0 Ready to start TLS')

If a client certificate is needed for the connection, it can be added
with *note SSLContext.load_cert_chain(): 295.

By contrast, if you create the SSL context by calling the *note
SSLContext: 294. constructor yourself, it will not have certificate
validation nor hostname checking enabled by default.  If you do so,
please read the paragraphs below to achieve a good security level.


File: python.info,  Node: Manual settings,  Next: Multi-processing,  Prev: Best defaults,  Up: Security considerations<2>

5.19.3.24 Manual settings
.........................

* Menu:

* Verifying certificates::
* Protocol versions::
* Cipher selection::


File: python.info,  Node: Verifying certificates,  Next: Protocol versions,  Up: Manual settings

5.19.3.25 Verifying certificates
................................

When calling the *note SSLContext: 294. constructor directly, *note
CERT_NONE: 3692. is the default.  Since it does not authenticate the
other peer, it can be insecure, especially in client mode where most of
the time you would like to ensure the authenticity of the server you’re
talking to.  Therefore, when in client mode, it is highly recommended to
use *note CERT_REQUIRED: 3681.  However, it is in itself not sufficient;
you also have to check that the server certificate, which can be
obtained by calling *note SSLSocket.getpeercert(): ff1, matches the
desired service.  For many protocols and applications, the service can
be identified by the hostname.  This common check is automatically
performed when *note SSLContext.check_hostname: 3694. is enabled.

Changed in version 3.7: Hostname matchings is now performed by OpenSSL.
Python no longer uses ‘match_hostname()’.

In server mode, if you want to authenticate your clients using the SSL
layer (rather than using a higher-level authentication mechanism),
you’ll also have to specify *note CERT_REQUIRED: 3681. and similarly
check the client certificate.


File: python.info,  Node: Protocol versions,  Next: Cipher selection,  Prev: Verifying certificates,  Up: Manual settings

5.19.3.26 Protocol versions
...........................

SSL versions 2 and 3 are considered insecure and are therefore dangerous
to use.  If you want maximum compatibility between clients and servers,
it is recommended to use *note PROTOCOL_TLS_CLIENT: 879. or *note
PROTOCOL_TLS_SERVER: 87a. as the protocol version.  SSLv2 and SSLv3 are
disabled by default.

     >>> client_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
     >>> client_context.minimum_version = ssl.TLSVersion.TLSv1_3
     >>> client_context.maximum_version = ssl.TLSVersion.TLSv1_3

The SSL context created above will only allow TLSv1.3 and later (if
supported by your system) connections to a server.  *note
PROTOCOL_TLS_CLIENT: 879. implies certificate validation and hostname
checks by default.  You have to load certificates into the context.


File: python.info,  Node: Cipher selection,  Prev: Protocol versions,  Up: Manual settings

5.19.3.27 Cipher selection
..........................

If you have advanced security requirements, fine-tuning of the ciphers
enabled when negotiating a SSL session is possible through the *note
SSLContext.set_ciphers(): 36c3. method.  Starting from Python 3.2.3, the
ssl module disables certain weak ciphers by default, but you may want to
further restrict the cipher choice.  Be sure to read OpenSSL’s
documentation about the cipher list format(1).  If you want to check
which ciphers are enabled by a given cipher list, use *note
SSLContext.get_ciphers(): d05. or the ‘openssl ciphers’ command on your
system.

   ---------- Footnotes ----------

   (1) https://docs.openssl.org/1.1.1/man1/ciphers/#cipher-list-format


File: python.info,  Node: Multi-processing,  Prev: Manual settings,  Up: Security considerations<2>

5.19.3.28 Multi-processing
..........................

If using this module as part of a multi-processed application (using,
for example the *note multiprocessing: 94. or *note concurrent.futures:
21. modules), be aware that OpenSSL’s internal random number generator
does not properly handle forked processes.  Applications must change the
PRNG state of the parent process if they use any SSL feature with *note
os.fork(): 197.  Any successful call of *note RAND_add(): 368c. or *note
RAND_bytes(): 527. is sufficient.


File: python.info,  Node: TLS 1 3,  Prev: Security considerations<2>,  Up: ssl — TLS/SSL wrapper for socket objects

5.19.3.29 TLS 1.3
.................

Added in version 3.7.

The TLS 1.3 protocol behaves slightly differently than previous version
of TLS/SSL. Some new TLS 1.3 features are not yet available.

   - TLS 1.3 uses a disjunct set of cipher suites.  All AES-GCM and
     ChaCha20 cipher suites are enabled by default.  The method *note
     SSLContext.set_ciphers(): 36c3. cannot enable or disable any TLS
     1.3 ciphers yet, but *note SSLContext.get_ciphers(): d05. returns
     them.

   - Session tickets are no longer sent as part of the initial handshake
     and are handled differently.  *note SSLSocket.session: 16b1. and
     *note SSLSession: d04. are not compatible with TLS 1.3.

   - Client-side certificates are also no longer verified during the
     initial handshake.  A server can request a certificate at any time.
     Clients process certificate requests while they send or receive
     application data from the server.

   - TLS 1.3 features like early data, deferred TLS client cert request,
     signature algorithm configuration, and rekeying are not supported
     yet.

See also
........

Class *note socket.socket: dcf.

     Documentation of underlying *note socket: cc. class

SSL/TLS Strong Encryption: An Introduction(1)

     Intro from the Apache HTTP Server documentation

RFC 1422: Privacy Enhancement for Internet Electronic Mail: Part II: Certificate-Based Key Management(2)

     Steve Kent

RFC 4086: Randomness Requirements for Security(3)

     Donald E. Eastlake, Jeffrey I. Schiller, Steve Crocker

RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile(4)

     David Cooper et al.

RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2(5)

     Tim Dierks and Eric Rescorla.

RFC 6066: Transport Layer Security (TLS) Extensions(6)

     Donald E. Eastlake

IANA TLS: Transport Layer Security (TLS) Parameters(7)

     IANA

RFC 7525: Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)(8)

     IETF

Mozilla's Server Side TLS recommendations(9)

     Mozilla

   ---------- Footnotes ----------

   (1) https://httpd.apache.org/docs/trunk/en/ssl/ssl_intro.html

   (2) https://datatracker.ietf.org/doc/html/rfc1422.html

   (3) https://datatracker.ietf.org/doc/html/rfc4086.html

   (4) https://datatracker.ietf.org/doc/html/rfc5280.html

   (5) https://datatracker.ietf.org/doc/html/rfc5246.html

   (6) https://datatracker.ietf.org/doc/html/rfc6066.html

   (7) 
https://www.iana.org/assignments/tls-parameters/tls-parameters.xml

   (8) https://datatracker.ietf.org/doc/html/rfc7525.html

   (9) https://wiki.mozilla.org/Security/Server_Side_TLS


File: python.info,  Node: select — Waiting for I/O completion,  Next: selectors — High-level I/O multiplexing,  Prev: ssl — TLS/SSL wrapper for socket objects,  Up: Networking and Interprocess Communication

5.19.4 ‘select’ — Waiting for I/O completion
--------------------------------------------

__________________________________________________________________

This module provides access to the ‘select()’ and ‘poll()’ functions
available in most operating systems, ‘devpoll()’ available on Solaris
and derivatives, ‘epoll()’ available on Linux 2.5+ and ‘kqueue()’
available on most BSD. Note that on Windows, it only works for sockets;
on other operating systems, it also works for other file types (in
particular, on Unix, it works on pipes).  It cannot be used on regular
files to determine whether a file has grown since it was last read.

     Note: The *note selectors: c2. module allows high-level and
     efficient I/O multiplexing, built upon the ‘select’ module
     primitives.  Users are encouraged to use the ‘selectors’ module
     instead, unless they want precise control over the OS-level
     primitives used.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The module defines the following:

 -- Exception: select.error

     A deprecated alias of *note OSError: 41a.

     Changed in version 3.3: Following PEP 3151(1), this class was made
     an alias of *note OSError: 41a.

 -- Function: select.devpoll ()

     (Only supported on Solaris and derivatives.)  Returns a ‘/dev/poll’
     polling object; see section *note /dev/poll Polling Objects: 36ed.
     below for the methods supported by devpoll objects.

     ‘devpoll()’ objects are linked to the number of file descriptors
     allowed at the time of instantiation.  If your program reduces this
     value, ‘devpoll()’ will fail.  If your program increases this
     value, ‘devpoll()’ may return an incomplete list of active file
     descriptors.

     The new file descriptor is *note non-inheritable: f30.

     Added in version 3.3.

     Changed in version 3.4: The new file descriptor is now
     non-inheritable.

 -- Function: select.epoll (sizehint=-1, flags=0)

     (Only supported on Linux 2.5.44 and newer.)  Return an edge polling
     object, which can be used as Edge or Level Triggered interface for
     I/O events.

     'sizehint' informs epoll about the expected number of events to be
     registered.  It must be positive, or ‘-1’ to use the default.  It
     is only used on older systems where ‘epoll_create1()’ is not
     available; otherwise it has no effect (though its value is still
     checked).

     'flags' is deprecated and completely ignored.  However, when
     supplied, its value must be ‘0’ or ‘select.EPOLL_CLOEXEC’,
     otherwise ‘OSError’ is raised.

     See the *note Edge and Level Trigger Polling (epoll) Objects: 36ee.
     section below for the methods supported by epolling objects.

     ‘epoll’ objects support the context management protocol: when used
     in a *note with: 5d5. statement, the new file descriptor is
     automatically closed at the end of the block.

     The new file descriptor is *note non-inheritable: f30.

     Changed in version 3.3: Added the 'flags' parameter.

     Changed in version 3.4: Support for the *note with: 5d5. statement
     was added.  The new file descriptor is now non-inheritable.

     Deprecated since version 3.4: The 'flags' parameter.
     ‘select.EPOLL_CLOEXEC’ is used by default now.  Use *note
     os.set_inheritable(): f32. to make the file descriptor inheritable.

 -- Function: select.poll ()

     (Not supported by all operating systems.)  Returns a polling
     object, which supports registering and unregistering file
     descriptors, and then polling them for I/O events; see section
     *note Polling Objects: 36ef. below for the methods supported by
     polling objects.

 -- Function: select.kqueue ()

     (Only supported on BSD.) Returns a kernel queue object; see section
     *note Kqueue Objects: 36f0. below for the methods supported by
     kqueue objects.

     The new file descriptor is *note non-inheritable: f30.

     Changed in version 3.4: The new file descriptor is now
     non-inheritable.

 -- Function: select.kevent (ident, filter=KQ_FILTER_READ,
          flags=KQ_EV_ADD, fflags=0, data=0, udata=0)

     (Only supported on BSD.) Returns a kernel event object; see section
     *note Kevent Objects: 36f2. below for the methods supported by
     kevent objects.

 -- Function: select.select (rlist, wlist, xlist, timeout=None)

     This is a straightforward interface to the Unix ‘select()’ system
     call.  The first three arguments are iterables of ‘waitable
     objects’: either integers representing file descriptors or objects
     with a parameterless method named *note fileno(): 15f5. returning
     such an integer:

        * 'rlist': wait until ready for reading

        * 'wlist': wait until ready for writing

        * 'xlist': wait for an “exceptional condition” (see the manual
          page for what your system considers such a condition)

     Empty iterables are allowed, but acceptance of three empty
     iterables is platform-dependent.  (It is known to work on Unix but
     not on Windows.)  The optional 'timeout' argument specifies a
     time-out as a floating-point number in seconds.  When the 'timeout'
     argument is omitted or ‘None’, the function blocks until at least
     one file descriptor is ready.  A time-out value of zero specifies a
     poll and never blocks.

     The return value is a triple of lists of objects that are ready:
     subsets of the first three arguments.  When the time-out is reached
     without a file descriptor becoming ready, three empty lists are
     returned.

     Among the acceptable object types in the iterables are Python *note
     file objects: 1208. (e.g.  ‘sys.stdin’, or objects returned by
     *note open(): 51f. or *note os.popen(): a96.), socket objects
     returned by *note socket.socket(): dcf.  You may also define a
     'wrapper' class yourself, as long as it has an appropriate *note
     fileno(): 15f5. method (that really returns a file descriptor, not
     just a random integer).

          Note: 
          File objects on Windows are not acceptable, but sockets are.
          On Windows, the underlying ‘select()’ function is provided by
          the WinSock library, and does not handle file descriptors that
          don’t originate from WinSock.

     Changed in version 3.5: The function is now retried with a
     recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception (see PEP 475(2) for the
     rationale), instead of raising *note InterruptedError: db6.

 -- Data: select.PIPE_BUF

     The minimum number of bytes which can be written without blocking
     to a pipe when the pipe has been reported as ready for writing by
     *note select(): dce, ‘poll()’ or another interface in this module.
     This doesn’t apply to other kinds of file-like objects such as
     sockets.

     This value is guaranteed by POSIX to be at least 512.

     *note Availability: 1ef7.: Unix

     Added in version 3.2.

* Menu:

* /dev/poll Polling Objects::
* Edge and Level Trigger Polling (epoll) Objects: Edge and Level Trigger Polling epoll Objects.
* Polling Objects::
* Kqueue Objects::
* Kevent Objects::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3151/

   (2) https://peps.python.org/pep-0475/


File: python.info,  Node: /dev/poll Polling Objects,  Next: Edge and Level Trigger Polling epoll Objects,  Up: select — Waiting for I/O completion

5.19.4.1 ‘/dev/poll’ Polling Objects
....................................

Solaris and derivatives have ‘/dev/poll’.  While ‘select()’ is
'O'('highest file descriptor') and ‘poll()’ is 'O'('number of file
descriptors'), ‘/dev/poll’ is 'O'('active file descriptors').

‘/dev/poll’ behaviour is very close to the standard ‘poll()’ object.

 -- Method: devpoll.close ()

     Close the file descriptor of the polling object.

     Added in version 3.4.

 -- Attribute: devpoll.closed

     ‘True’ if the polling object is closed.

     Added in version 3.4.

 -- Method: devpoll.fileno ()

     Return the file descriptor number of the polling object.

     Added in version 3.4.

 -- Method: devpoll.register (fd[, eventmask])

     Register a file descriptor with the polling object.  Future calls
     to the *note poll(): 2da7. method will then check whether the file
     descriptor has any pending I/O events.  'fd' can be either an
     integer, or an object with a *note fileno(): 15f5. method that
     returns an integer.  File objects implement ‘fileno()’, so they can
     also be used as the argument.

     'eventmask' is an optional bitmask describing the type of events
     you want to check for.  The constants are the same as with ‘poll()’
     object.  The default value is a combination of the constants
     ‘POLLIN’, ‘POLLPRI’, and ‘POLLOUT’.

          Warning: Registering a file descriptor that’s already
          registered is not an error, but the result is undefined.  The
          appropriate action is to unregister or modify it first.  This
          is an important difference compared with ‘poll()’.

 -- Method: devpoll.modify (fd[, eventmask])

     This method does an *note unregister(): 36f6. followed by a *note
     register(): 36f4.  It is (a bit) more efficient than doing the same
     explicitly.

 -- Method: devpoll.unregister (fd)

     Remove a file descriptor being tracked by a polling object.  Just
     like the *note register(): 36f4. method, 'fd' can be an integer or
     an object with a *note fileno(): 15f5. method that returns an
     integer.

     Attempting to remove a file descriptor that was never registered is
     safely ignored.

 -- Method: devpoll.poll ([timeout])

     Polls the set of registered file descriptors, and returns a
     possibly empty list containing ‘(fd, event)’ 2-tuples for the
     descriptors that have events or errors to report.  'fd' is the file
     descriptor, and 'event' is a bitmask with bits set for the reported
     events for that descriptor — ‘POLLIN’ for waiting input, ‘POLLOUT’
     to indicate that the descriptor can be written to, and so forth.
     An empty list indicates that the call timed out and no file
     descriptors had any events to report.  If 'timeout' is given, it
     specifies the length of time in milliseconds which the system will
     wait for events before returning.  If 'timeout' is omitted, -1, or
     *note None: 678, the call will block until there is an event for
     this poll object.

     Changed in version 3.5: The function is now retried with a
     recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception (see PEP 475(1) for the
     rationale), instead of raising *note InterruptedError: db6.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/


File: python.info,  Node: Edge and Level Trigger Polling epoll Objects,  Next: Polling Objects,  Prev: /dev/poll Polling Objects,  Up: select — Waiting for I/O completion

5.19.4.2 Edge and Level Trigger Polling (epoll) Objects
.......................................................

     ‘https://linux.die.net/man/4/epoll’

     'eventmask'

     Constant                      Meaning
                                   
     ----------------------------------------------------------------------------------
                                   
     ‘EPOLLIN’                     Available for read
                                   
                                   
     ‘EPOLLOUT’                    Available for write
                                   
                                   
     ‘EPOLLPRI’                    Urgent data for read
                                   
                                   
     ‘EPOLLERR’                    Error condition happened on the assoc.  fd
                                   
                                   
     ‘EPOLLHUP’                    Hang up happened on the assoc.  fd
                                   
                                   
     ‘EPOLLET’                     Set Edge Trigger behavior, the default is Level
                                   Trigger behavior
                                   
                                   
     ‘EPOLLONESHOT’                Set one-shot behavior.  After one event is pulled
                                   out, the fd is internally disabled
                                   
                                   
     ‘EPOLLEXCLUSIVE’              Wake only one epoll object when the associated fd
                                   has an event.  The default (if this flag is not
                                   set) is to wake all epoll objects polling on a
                                   fd.
                                   
                                   
     ‘EPOLLRDHUP’                  Stream socket peer closed connection or shut down
                                   writing half of connection.
                                   
                                   
     ‘EPOLLRDNORM’                 Equivalent to ‘EPOLLIN’
                                   
                                   
     ‘EPOLLRDBAND’                 Priority data band can be read.
                                   
                                   
     ‘EPOLLWRNORM’                 Equivalent to ‘EPOLLOUT’
                                   
                                   
     ‘EPOLLWRBAND’                 Priority data may be written.
                                   
                                   
     ‘EPOLLMSG’                    Ignored.
                                   

     Added in version 3.6: ‘EPOLLEXCLUSIVE’ was added.  It’s only
     supported by Linux Kernel 4.5 or later.

 -- Method: epoll.close ()

     Close the control file descriptor of the epoll object.

 -- Attribute: epoll.closed

     ‘True’ if the epoll object is closed.

 -- Method: epoll.fileno ()

     Return the file descriptor number of the control fd.

 -- Method: epoll.fromfd (fd)

     Create an epoll object from a given file descriptor.

 -- Method: epoll.register (fd[, eventmask])

     Register a fd descriptor with the epoll object.

 -- Method: epoll.modify (fd, eventmask)

     Modify a registered file descriptor.

 -- Method: epoll.unregister (fd)

     Remove a registered file descriptor from the epoll object.

     Changed in version 3.9: The method no longer ignores the *note
     EBADF: 965. error.

 -- Method: epoll.poll (timeout=None, maxevents=-1)

     Wait for events.  timeout in seconds (float)

     Changed in version 3.5: The function is now retried with a
     recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception (see PEP 475(1) for the
     rationale), instead of raising *note InterruptedError: db6.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/


File: python.info,  Node: Polling Objects,  Next: Kqueue Objects,  Prev: Edge and Level Trigger Polling epoll Objects,  Up: select — Waiting for I/O completion

5.19.4.3 Polling Objects
........................

The ‘poll()’ system call, supported on most Unix systems, provides
better scalability for network servers that service many, many clients
at the same time.  ‘poll()’ scales better because the system call only
requires listing the file descriptors of interest, while ‘select()’
builds a bitmap, turns on bits for the fds of interest, and then
afterward the whole bitmap has to be linearly scanned again.  ‘select()’
is 'O'('highest file descriptor'), while ‘poll()’ is 'O'('number of file
descriptors').

 -- Method: poll.register (fd[, eventmask])

     Register a file descriptor with the polling object.  Future calls
     to the *note poll(): 2da7. method will then check whether the file
     descriptor has any pending I/O events.  'fd' can be either an
     integer, or an object with a *note fileno(): 15f5. method that
     returns an integer.  File objects implement ‘fileno()’, so they can
     also be used as the argument.

     'eventmask' is an optional bitmask describing the type of events
     you want to check for, and can be a combination of the constants
     ‘POLLIN’, ‘POLLPRI’, and ‘POLLOUT’, described in the table below.
     If not specified, the default value used will check for all 3 types
     of events.

     Constant                Meaning
                             
     -----------------------------------------------------------------------
                             
     ‘POLLIN’                There is data to read
                             
                             
     ‘POLLPRI’               There is urgent data to read
                             
                             
     ‘POLLOUT’               Ready for output: writing will not block
                             
                             
     ‘POLLERR’               Error condition of some sort
                             
                             
     ‘POLLHUP’               Hung up
                             
                             
     ‘POLLRDHUP’             Stream socket peer closed connection, or
                             shut down writing half of connection
                             
                             
     ‘POLLNVAL’              Invalid request: descriptor not open
                             

     Registering a file descriptor that’s already registered is not an
     error, and has the same effect as registering the descriptor
     exactly once.

 -- Method: poll.modify (fd, eventmask)

     Modifies an already registered fd.  This has the same effect as
     ‘register(fd, eventmask)’.  Attempting to modify a file descriptor
     that was never registered causes an *note OSError: 41a. exception
     with errno ‘ENOENT’ to be raised.

 -- Method: poll.unregister (fd)

     Remove a file descriptor being tracked by a polling object.  Just
     like the *note register(): 36fe. method, 'fd' can be an integer or
     an object with a *note fileno(): 15f5. method that returns an
     integer.

     Attempting to remove a file descriptor that was never registered
     causes a *note KeyError: 345. exception to be raised.

 -- Method: poll.poll ([timeout])

     Polls the set of registered file descriptors, and returns a
     possibly empty list containing ‘(fd, event)’ 2-tuples for the
     descriptors that have events or errors to report.  'fd' is the file
     descriptor, and 'event' is a bitmask with bits set for the reported
     events for that descriptor — ‘POLLIN’ for waiting input, ‘POLLOUT’
     to indicate that the descriptor can be written to, and so forth.
     An empty list indicates that the call timed out and no file
     descriptors had any events to report.  If 'timeout' is given, it
     specifies the length of time in milliseconds which the system will
     wait for events before returning.  If 'timeout' is omitted,
     negative, or *note None: 678, the call will block until there is an
     event for this poll object.

     Changed in version 3.5: The function is now retried with a
     recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception (see PEP 475(1) for the
     rationale), instead of raising *note InterruptedError: db6.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/


File: python.info,  Node: Kqueue Objects,  Next: Kevent Objects,  Prev: Polling Objects,  Up: select — Waiting for I/O completion

5.19.4.4 Kqueue Objects
.......................

 -- Method: kqueue.close ()

     Close the control file descriptor of the kqueue object.

 -- Attribute: kqueue.closed

     ‘True’ if the kqueue object is closed.

 -- Method: kqueue.fileno ()

     Return the file descriptor number of the control fd.

 -- Method: kqueue.fromfd (fd)

     Create a kqueue object from a given file descriptor.

 -- Method: kqueue.control (changelist, max_events[, timeout]) ->
          eventlist

     Low level interface to kevent

        - changelist must be an iterable of kevent objects or ‘None’

        - max_events must be 0 or a positive integer

        - timeout in seconds (floats possible); the default is ‘None’,
          to wait forever

     Changed in version 3.5: The function is now retried with a
     recomputed timeout when interrupted by a signal, except if the
     signal handler raises an exception (see PEP 475(1) for the
     rationale), instead of raising *note InterruptedError: db6.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/


File: python.info,  Node: Kevent Objects,  Prev: Kqueue Objects,  Up: select — Waiting for I/O completion

5.19.4.5 Kevent Objects
.......................

‘https://man.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2’

 -- Attribute: kevent.ident

     Value used to identify the event.  The interpretation depends on
     the filter but it’s usually the file descriptor.  In the
     constructor ident can either be an int or an object with a *note
     fileno(): 15f5. method.  kevent stores the integer internally.

 -- Attribute: kevent.filter

     Name of the kernel filter.

     Constant                        Meaning
                                     
     ----------------------------------------------------------------------------------
                                     
     ‘KQ_FILTER_READ’                Takes a descriptor and returns whenever there
                                     is data available to read
                                     
                                     
     ‘KQ_FILTER_WRITE’               Takes a descriptor and returns whenever there
                                     is data available to write
                                     
                                     
     ‘KQ_FILTER_AIO’                 AIO requests
                                     
                                     
     ‘KQ_FILTER_VNODE’               Returns when one or more of the requested
                                     events watched in 'fflag' occurs
                                     
                                     
     ‘KQ_FILTER_PROC’                Watch for events on a process id
                                     
                                     
     ‘KQ_FILTER_NETDEV’              Watch for events on a network device [not
                                     available on macOS]
                                     
                                     
     ‘KQ_FILTER_SIGNAL’              Returns whenever the watched signal is
                                     delivered to the process
                                     
                                     
     ‘KQ_FILTER_TIMER’               Establishes an arbitrary timer
                                     

 -- Attribute: kevent.flags

     Filter action.

     Constant                        Meaning
                                     
     ----------------------------------------------------------------------------------
                                     
     ‘KQ_EV_ADD’                     Adds or modifies an event
                                     
                                     
     ‘KQ_EV_DELETE’                  Removes an event from the queue
                                     
                                     
     ‘KQ_EV_ENABLE’                  Permits control() to return the event
                                     
                                     
     ‘KQ_EV_DISABLE’                 Disables event
                                     
                                     
     ‘KQ_EV_ONESHOT’                 Removes event after first occurrence
                                     
                                     
     ‘KQ_EV_CLEAR’                   Reset the state after an event is retrieved
                                     
                                     
     ‘KQ_EV_SYSFLAGS’                internal event
                                     
                                     
     ‘KQ_EV_FLAG1’                   internal event
                                     
                                     
     ‘KQ_EV_EOF’                     Filter specific EOF condition
                                     
                                     
     ‘KQ_EV_ERROR’                   See return values
                                     

 -- Attribute: kevent.fflags

     Filter specific flags.

     ‘KQ_FILTER_READ’ and ‘KQ_FILTER_WRITE’ filter flags:

     Constant                         Meaning
                                      
     ----------------------------------------------------------------------------------
                                      
     ‘KQ_NOTE_LOWAT’                  low water mark of a socket buffer
                                      

     ‘KQ_FILTER_VNODE’ filter flags:

     Constant                         Meaning
                                      
     ----------------------------------------------------------------------------------
                                      
     ‘KQ_NOTE_DELETE’                 'unlink()' was called
                                      
                                      
     ‘KQ_NOTE_WRITE’                  a write occurred
                                      
                                      
     ‘KQ_NOTE_EXTEND’                 the file was extended
                                      
                                      
     ‘KQ_NOTE_ATTRIB’                 an attribute was changed
                                      
                                      
     ‘KQ_NOTE_LINK’                   the link count has changed
                                      
                                      
     ‘KQ_NOTE_RENAME’                 the file was renamed
                                      
                                      
     ‘KQ_NOTE_REVOKE’                 access to the file was revoked
                                      

     ‘KQ_FILTER_PROC’ filter flags:

     Constant                         Meaning
                                      
     ----------------------------------------------------------------------------------
                                      
     ‘KQ_NOTE_EXIT’                   the process has exited
                                      
                                      
     ‘KQ_NOTE_FORK’                   the process has called 'fork()'
                                      
                                      
     ‘KQ_NOTE_EXEC’                   the process has executed a new process
                                      
                                      
     ‘KQ_NOTE_PCTRLMASK’              internal filter flag
                                      
                                      
     ‘KQ_NOTE_PDATAMASK’              internal filter flag
                                      
                                      
     ‘KQ_NOTE_TRACK’                  follow a process across 'fork()'
                                      
                                      
     ‘KQ_NOTE_CHILD’                  returned on the child process for 'NOTE_TRACK'
                                      
                                      
     ‘KQ_NOTE_TRACKERR’               unable to attach to a child
                                      

     ‘KQ_FILTER_NETDEV’ filter flags (not available on macOS):

     Constant                         Meaning
                                      
     ----------------------------------------------------------------------------------
                                      
     ‘KQ_NOTE_LINKUP’                 link is up
                                      
                                      
     ‘KQ_NOTE_LINKDOWN’               link is down
                                      
                                      
     ‘KQ_NOTE_LINKINV’                link state is invalid
                                      

 -- Attribute: kevent.data

     Filter specific data.

 -- Attribute: kevent.udata

     User defined value.


File: python.info,  Node: selectors — High-level I/O multiplexing,  Next: signal — Set handlers for asynchronous events,  Prev: select — Waiting for I/O completion,  Up: Networking and Interprocess Communication

5.19.5 ‘selectors’ — High-level I/O multiplexing
------------------------------------------------

Added in version 3.4.

'Source code:' Lib/selectors.py(1)

__________________________________________________________________

* Menu:

* Introduction: Introduction<10>.
* Classes: Classes<4>.
* Examples: Examples<21>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/selectors.py


File: python.info,  Node: Introduction<10>,  Next: Classes<4>,  Up: selectors — High-level I/O multiplexing

5.19.5.1 Introduction
.....................

This module allows high-level and efficient I/O multiplexing, built upon
the *note select: c1. module primitives.  Users are encouraged to use
this module instead, unless they want precise control over the OS-level
primitives used.

It defines a *note BaseSelector: 3711. abstract base class, along with
several concrete implementations (*note KqueueSelector: 35f2, *note
EpollSelector: bf6.…), that can be used to wait for I/O readiness
notification on multiple file objects.  In the following, “file object”
refers to any object with a *note fileno(): 15f5. method, or a raw file
descriptor.  See *note file object: 1208.

*note DefaultSelector: 3712. is an alias to the most efficient
implementation available on the current platform: this should be the
default choice for most users.

     Note: The type of file objects supported depends on the platform:
     on Windows, sockets are supported, but not pipes, whereas on Unix,
     both are supported (some other types may be supported as well, such
     as fifos or special file devices).

See also
........

*note select: c1.

     Low-level I/O multiplexing module.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.


File: python.info,  Node: Classes<4>,  Next: Examples<21>,  Prev: Introduction<10>,  Up: selectors — High-level I/O multiplexing

5.19.5.2 Classes
................

Classes hierarchy:

     BaseSelector
     +-- SelectSelector
     +-- PollSelector
     +-- EpollSelector
     +-- DevpollSelector
     +-- KqueueSelector

In the following, 'events' is a bitwise mask indicating which I/O events
should be waited for on a given file object.  It can be a combination of
the module’s constants below:

     Constant                    Meaning
                                 
     --------------------------------------------------------------------------------
                                 
      -- Data:                   Available for read
               selectors.EVENT_READ

      -- Data:                   Available for write
               selectors.EVENT_WRITE

 -- Class: selectors.SelectorKey

     A ‘SelectorKey’ is a *note namedtuple: 1ca. used to associate a
     file object to its underlying file descriptor, selected event mask
     and attached data.  It is returned by several *note BaseSelector:
     3711. methods.

      -- Attribute: fileobj

          File object registered.

      -- Attribute: fd

          Underlying file descriptor.

      -- Attribute: events

          Events that must be waited for on this file object.

      -- Attribute: data

          Optional opaque data associated to this file object: for
          example, this could be used to store a per-client session ID.

 -- Class: selectors.BaseSelector

     A ‘BaseSelector’ is used to wait for I/O event readiness on
     multiple file objects.  It supports file stream registration,
     unregistration, and a method to wait for I/O events on those
     streams, with an optional timeout.  It’s an abstract base class, so
     cannot be instantiated.  Use *note DefaultSelector: 3712. instead,
     or one of *note SelectSelector: 35ef, *note KqueueSelector: 35f2.
     etc.  if you want to specifically use an implementation, and your
     platform supports it.  ‘BaseSelector’ and its concrete
     implementations support the *note context manager: 5d7. protocol.

      -- Method: abstractmethod register (fileobj, events, data=None)

          Register a file object for selection, monitoring it for I/O
          events.

          'fileobj' is the file object to monitor.  It may either be an
          integer file descriptor or an object with a ‘fileno()’ method.
          'events' is a bitwise mask of events to monitor.  'data' is an
          opaque object.

          This returns a new *note SelectorKey: 3716. instance, or
          raises a *note ValueError: 202. in case of invalid event mask
          or file descriptor, or *note KeyError: 345. if the file object
          is already registered.

      -- Method: abstractmethod unregister (fileobj)

          Unregister a file object from selection, removing it from
          monitoring.  A file object shall be unregistered prior to
          being closed.

          'fileobj' must be a file object previously registered.

          This returns the associated *note SelectorKey: 3716. instance,
          or raises a *note KeyError: 345. if 'fileobj' is not
          registered.  It will raise *note ValueError: 202. if 'fileobj'
          is invalid (e.g.  it has no ‘fileno()’ method or its
          ‘fileno()’ method has an invalid return value).

      -- Method: modify (fileobj, events, data=None)

          Change a registered file object’s monitored events or attached
          data.

          This is equivalent to ‘BaseSelector.unregister(fileobj)’
          followed by ‘BaseSelector.register(fileobj, events, data)’,
          except that it can be implemented more efficiently.

          This returns a new *note SelectorKey: 3716. instance, or
          raises a *note ValueError: 202. in case of invalid event mask
          or file descriptor, or *note KeyError: 345. if the file object
          is not registered.

      -- Method: abstractmethod select (timeout=None)

          Wait until some registered file objects become ready, or the
          timeout expires.

          If ‘timeout > 0’, this specifies the maximum wait time, in
          seconds.  If ‘timeout <= 0’, the call won’t block, and will
          report the currently ready file objects.  If 'timeout' is
          ‘None’, the call will block until a monitored file object
          becomes ready.

          This returns a list of ‘(key, events)’ tuples, one for each
          ready file object.

          'key' is the *note SelectorKey: 3716. instance corresponding
          to a ready file object.  'events' is a bitmask of events ready
          on this file object.

               Note: This method can return before any file object
               becomes ready or the timeout has elapsed if the current
               process receives a signal: in this case, an empty list
               will be returned.

          Changed in version 3.5: The selector is now retried with a
          recomputed timeout when interrupted by a signal if the signal
          handler did not raise an exception (see PEP 475(1) for the
          rationale), instead of returning an empty list of events
          before the timeout.

      -- Method: close ()

          Close the selector.

          This must be called to make sure that any underlying resource
          is freed.  The selector shall not be used once it has been
          closed.

      -- Method: get_key (fileobj)

          Return the key associated with a registered file object.

          This returns the *note SelectorKey: 3716. instance associated
          to this file object, or raises *note KeyError: 345. if the
          file object is not registered.

      -- Method: abstractmethod get_map ()

          Return a mapping of file objects to selector keys.

          This returns a *note Mapping: 8d3. instance mapping registered
          file objects to their associated *note SelectorKey: 3716.
          instance.

 -- Class: selectors.DefaultSelector

     The default selector class, using the most efficient implementation
     available on the current platform.  This should be the default
     choice for most users.

 -- Class: selectors.SelectSelector

     *note select.select(): dce.-based selector.

 -- Class: selectors.PollSelector

     *note select.poll(): 2da7.-based selector.

 -- Class: selectors.EpollSelector

     *note select.epoll(): fcd.-based selector.

      -- Method: fileno ()

          This returns the file descriptor used by the underlying *note
          select.epoll(): fcd. object.

 -- Class: selectors.DevpollSelector

     *note select.devpoll(): fcf.-based selector.

      -- Method: fileno ()

          This returns the file descriptor used by the underlying *note
          select.devpoll(): fcf. object.

     Added in version 3.5.

 -- Class: selectors.KqueueSelector

     *note select.kqueue(): 17dd.-based selector.

      -- Method: fileno ()

          This returns the file descriptor used by the underlying *note
          select.kqueue(): 17dd. object.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0475/


File: python.info,  Node: Examples<21>,  Prev: Classes<4>,  Up: selectors — High-level I/O multiplexing

5.19.5.3 Examples
.................

Here is a simple echo server implementation:

     import selectors
     import socket

     sel = selectors.DefaultSelector()

     def accept(sock, mask):
         conn, addr = sock.accept()  # Should be ready
         print('accepted', conn, 'from', addr)
         conn.setblocking(False)
         sel.register(conn, selectors.EVENT_READ, read)

     def read(conn, mask):
         data = conn.recv(1000)  # Should be ready
         if data:
             print('echoing', repr(data), 'to', conn)
             conn.send(data)  # Hope it won't block
         else:
             print('closing', conn)
             sel.unregister(conn)
             conn.close()

     sock = socket.socket()
     sock.bind(('localhost', 1234))
     sock.listen(100)
     sock.setblocking(False)
     sel.register(sock, selectors.EVENT_READ, accept)

     while True:
         events = sel.select()
         for key, mask in events:
             callback = key.data
             callback(key.fileobj, mask)


File: python.info,  Node: signal — Set handlers for asynchronous events,  Next: mmap — Memory-mapped file support,  Prev: selectors — High-level I/O multiplexing,  Up: Networking and Interprocess Communication

5.19.6 ‘signal’ — Set handlers for asynchronous events
------------------------------------------------------

'Source code:' Lib/signal.py(1)

__________________________________________________________________

This module provides mechanisms to use signal handlers in Python.

* Menu:

* General rules::
* Module contents: Module contents<3>.
* Examples: Examples<22>.
* Note on SIGPIPE::
* Note on Signal Handlers and Exceptions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/signal.py


File: python.info,  Node: General rules,  Next: Module contents<3>,  Up: signal — Set handlers for asynchronous events

5.19.6.1 General rules
......................

The *note signal.signal(): 1178. function allows defining custom
handlers to be executed when a signal is received.  A small number of
default handlers are installed: *note SIGPIPE: 3729. is ignored (so
write errors on pipes and sockets can be reported as ordinary Python
exceptions) and *note SIGINT: 84a. is translated into a *note
KeyboardInterrupt: 9dc. exception if the parent process has not changed
it.

A handler for a particular signal, once set, remains installed until it
is explicitly reset (Python emulates the BSD style interface regardless
of the underlying implementation), with the exception of the handler for
*note SIGCHLD: 2de3, which follows the underlying implementation.

On WebAssembly platforms, signals are emulated and therefore behave
differently.  Several functions and signals are not available on these
platforms.

* Menu:

* Execution of Python signal handlers::
* Signals and threads::


File: python.info,  Node: Execution of Python signal handlers,  Next: Signals and threads,  Up: General rules

5.19.6.2 Execution of Python signal handlers
............................................

A Python signal handler does not get executed inside the low-level (C)
signal handler.  Instead, the low-level signal handler sets a flag which
tells the *note virtual machine: 372b. to execute the corresponding
Python signal handler at a later point (for example, at the next *note
bytecode: 187. instruction).  This has consequences:

   * It makes little sense to catch synchronous errors like *note
     SIGFPE: 10bf. or *note SIGSEGV: 10be. that are caused by an invalid
     operation in C code.  Python will return from the signal handler to
     the C code, which is likely to raise the same signal again, causing
     Python to apparently hang.  From Python 3.3 onwards, you can use
     the *note faulthandler: 58. module to report on synchronous errors.

   * A long-running calculation implemented purely in C (such as regular
     expression matching on a large body of text) may run uninterrupted
     for an arbitrary amount of time, regardless of any signals
     received.  The Python signal handlers will be called when the
     calculation finishes.

   * If the handler raises an exception, it will be raised “out of thin
     air” in the main thread.  See the *note note below: 2444. for a
     discussion.


File: python.info,  Node: Signals and threads,  Prev: Execution of Python signal handlers,  Up: General rules

5.19.6.3 Signals and threads
............................

Python signal handlers are always executed in the main Python thread of
the main interpreter, even if the signal was received in another thread.
This means that signals can’t be used as a means of inter-thread
communication.  You can use the synchronization primitives from the
*note threading: ed. module instead.

Besides, only the main thread of the main interpreter is allowed to set
a new signal handler.

     Warning: Synchronization primitives such as *note threading.Lock:
     178a. should not be used within signal handlers.  Doing so can lead
     to unexpected deadlocks.


File: python.info,  Node: Module contents<3>,  Next: Examples<22>,  Prev: General rules,  Up: signal — Set handlers for asynchronous events

5.19.6.4 Module contents
........................

Changed in version 3.5: signal (SIG*), handler (*note SIG_DFL: 1957,
*note SIG_IGN: 1956.) and sigmask (*note SIG_BLOCK: 372f, *note
SIG_UNBLOCK: 3730, *note SIG_SETMASK: 3731.) related constants listed
below were turned into *note enums: d06. (*note Signals: 3732, *note
Handlers: 3733. and *note Sigmasks: 3734. respectively).  *note
getsignal(): 17bd, *note pthread_sigmask(): 1174, *note sigpending():
1176. and *note sigwait(): 1177. functions return human-readable ‘enums’
as ‘Signals’ objects.

The signal module defines three enums:

 -- Class: signal.Signals

     *note enum.IntEnum: d06. collection of SIG* constants and the
     CTRL_* constants.

     Added in version 3.5.

 -- Class: signal.Handlers

     *note enum.IntEnum: d06. collection of the constants *note SIG_DFL:
     1957. and *note SIG_IGN: 1956.

     Added in version 3.5.

 -- Class: signal.Sigmasks

     *note enum.IntEnum: d06. collection of the constants *note
     SIG_BLOCK: 372f, *note SIG_UNBLOCK: 3730. and *note SIG_SETMASK:
     3731.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigprocmask(2)(1)’ and ‘pthread_sigmask(3)(2)’
     for further information.

     Added in version 3.5.

The variables defined in the ‘signal’ module are:

 -- Data: signal.SIG_DFL

     This is one of two standard signal handling options; it will simply
     perform the default function for the signal.  For example, on most
     systems the default action for *note SIGQUIT: 3735. is to dump core
     and exit, while the default action for *note SIGCHLD: 2de3. is to
     simply ignore it.

 -- Data: signal.SIG_IGN

     This is another standard signal handler, which will simply ignore
     the given signal.

 -- Data: signal.SIGABRT

     Abort signal from ‘abort(3)(3)’.

 -- Data: signal.SIGALRM

     Timer signal from ‘alarm(2)(4)’.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGBREAK

     Interrupt from keyboard (CTRL + BREAK).

     *note Availability: 1ef7.: Windows.

 -- Data: signal.SIGBUS

     Bus error (bad memory access).

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGCHLD

     Child process stopped or terminated.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGCLD

     Alias to *note SIGCHLD: 2de3.

     *note Availability: 1ef7.: not macOS.

 -- Data: signal.SIGCONT

     Continue the process if it is currently stopped

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGFPE

     Floating-point exception.  For example, division by zero.

     See also
     ........

     *note ZeroDivisionError: 94f. is raised when the second argument of
     a division or modulo operation is zero.

 -- Data: signal.SIGHUP

     Hangup detected on controlling terminal or death of controlling
     process.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGILL

     Illegal instruction.

 -- Data: signal.SIGINT

     Interrupt from keyboard (CTRL + C).

     Default action is to raise *note KeyboardInterrupt: 9dc.

 -- Data: signal.SIGKILL

     Kill signal.

     It cannot be caught, blocked, or ignored.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGPIPE

     Broken pipe: write to pipe with no readers.

     Default action is to ignore the signal.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGPROF

     Profiling timer expired.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGQUIT

     Terminal quit signal.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGSEGV

     Segmentation fault: invalid memory reference.

 -- Data: signal.SIGSTOP

     Stop executing (cannot be caught or ignored).

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGSTKFLT

     Stack fault on coprocessor.  The Linux kernel does not raise this
     signal: it can only be raised in user space.

     *note Availability: 1ef7.: Linux.

     On architectures where the signal is available.  See the man page
     ‘signal(7)(5)’ for further information.

     Added in version 3.11.

 -- Data: signal.SIGTERM

     Termination signal.

 -- Data: signal.SIGUSR1

     User-defined signal 1.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGUSR2

     User-defined signal 2.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGVTALRM

     Virtual timer expired.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGWINCH

     Window resize signal.

     *note Availability: 1ef7.: Unix.

 -- Data: signal.SIGXCPU

     CPU time limit exceeded.

     *note Availability: 1ef7.: Unix.

 -- Data: SIG*

     All the signal numbers are defined symbolically.  For example, the
     hangup signal is defined as *note signal.SIGHUP: 3739.; the
     variable names are identical to the names used in C programs, as
     found in ‘<signal.h>’.  The Unix man page for ‘‘signal’’ lists the
     existing signals (on some systems this is ‘signal(2)(6)’, on others
     the list is in ‘signal(7)(7)’).  Note that not all systems define
     the same set of signal names; only those names defined by the
     system are defined by this module.

 -- Data: signal.CTRL_C_EVENT

     The signal corresponding to the ‘Ctrl’+‘C’ keystroke event.  This
     signal can only be used with *note os.kill(): 13b4.

     *note Availability: 1ef7.: Windows.

     Added in version 3.2.

 -- Data: signal.CTRL_BREAK_EVENT

     The signal corresponding to the ‘Ctrl’+‘Break’ keystroke event.
     This signal can only be used with *note os.kill(): 13b4.

     *note Availability: 1ef7.: Windows.

     Added in version 3.2.

 -- Data: signal.NSIG

     One more than the number of the highest signal number.  Use *note
     valid_signals(): 3741. to get valid signal numbers.

 -- Data: signal.ITIMER_REAL

     Decrements interval timer in real time, and delivers *note SIGALRM:
     3736. upon expiration.

 -- Data: signal.ITIMER_VIRTUAL

     Decrements interval timer only when the process is executing, and
     delivers SIGVTALRM upon expiration.

 -- Data: signal.ITIMER_PROF

     Decrements interval timer both when the process executes and when
     the system is executing on behalf of the process.  Coupled with
     ITIMER_VIRTUAL, this timer is usually used to profile the time
     spent by the application in user and kernel space.  SIGPROF is
     delivered upon expiration.

 -- Data: signal.SIG_BLOCK

     A possible value for the 'how' parameter to *note
     pthread_sigmask(): 1174. indicating that signals are to be blocked.

     Added in version 3.3.

 -- Data: signal.SIG_UNBLOCK

     A possible value for the 'how' parameter to *note
     pthread_sigmask(): 1174. indicating that signals are to be
     unblocked.

     Added in version 3.3.

 -- Data: signal.SIG_SETMASK

     A possible value for the 'how' parameter to *note
     pthread_sigmask(): 1174. indicating that the signal mask is to be
     replaced.

     Added in version 3.3.

The ‘signal’ module defines one exception:

 -- Exception: signal.ItimerError

     Raised to signal an error from the underlying *note setitimer():
     3746. or *note getitimer(): 3747. implementation.  Expect this
     error if an invalid interval timer or a negative time is passed to
     ‘setitimer()’.  This error is a subtype of *note OSError: 41a.

     Added in version 3.3: This error used to be a subtype of *note
     IOError: 1090, which is now an alias of *note OSError: 41a.

The ‘signal’ module defines the following functions:

 -- Function: signal.alarm (time)

     If 'time' is non-zero, this function requests that a *note SIGALRM:
     3736. signal be sent to the process in 'time' seconds.  Any
     previously scheduled alarm is canceled (only one alarm can be
     scheduled at any time).  The returned value is then the number of
     seconds before any previously set alarm was to have been delivered.
     If 'time' is zero, no alarm is scheduled, and any scheduled alarm
     is canceled.  If the return value is zero, no alarm is currently
     scheduled.

     *note Availability: 1ef7.: Unix.

     See the man page ‘alarm(2)(8)’ for further information.

 -- Function: signal.getsignal (signalnum)

     Return the current signal handler for the signal 'signalnum'.  The
     returned value may be a callable Python object, or one of the
     special values *note signal.SIG_IGN: 1956, *note signal.SIG_DFL:
     1957. or *note None: 678.  Here, ‘signal.SIG_IGN’ means that the
     signal was previously ignored, ‘signal.SIG_DFL’ means that the
     default way of handling the signal was previously in use, and
     ‘None’ means that the previous signal handler was not installed
     from Python.

 -- Function: signal.strsignal (signalnum)

     Returns the description of signal 'signalnum', such as “Interrupt”
     for *note SIGINT: 84a.  Returns *note None: 678. if 'signalnum' has
     no description.  Raises *note ValueError: 202. if 'signalnum' is
     invalid.

     Added in version 3.8.

 -- Function: signal.valid_signals ()

     Return the set of valid signal numbers on this platform.  This can
     be less than ‘range(1, NSIG)’ if some signals are reserved by the
     system for internal use.

     Added in version 3.8.

 -- Function: signal.pause ()

     Cause the process to sleep until a signal is received; the
     appropriate handler will then be called.  Returns nothing.

     *note Availability: 1ef7.: Unix.

     See the man page ‘signal(2)(9)’ for further information.

     See also *note sigwait(): 1177, *note sigwaitinfo(): dd9, *note
     sigtimedwait(): dd8. and *note sigpending(): 1176.

 -- Function: signal.raise_signal (signum)

     Sends a signal to the calling process.  Returns nothing.

     Added in version 3.8.

 -- Function: signal.pidfd_send_signal (pidfd, sig, siginfo=None,
          flags=0)

     Send signal 'sig' to the process referred to by file descriptor
     'pidfd'.  Python does not currently support the 'siginfo'
     parameter; it must be ‘None’.  The 'flags' argument is provided for
     future extensions; no flag values are currently defined.

     See the ‘pidfd_send_signal(2)(10)’ man page for more information.

     *note Availability: 1ef7.: Linux >= 5.1, Android >= *note
     build-time: ba8. API level 31

     Added in version 3.9.

 -- Function: signal.pthread_kill (thread_id, signalnum)

     Send the signal 'signalnum' to the thread 'thread_id', another
     thread in the same process as the caller.  The target thread can be
     executing any code (Python or not).  However, if the target thread
     is executing the Python interpreter, the Python signal handlers
     will be *note executed by the main thread of the main interpreter:
     372d.  Therefore, the only point of sending a signal to a
     particular Python thread would be to force a running system call to
     fail with *note InterruptedError: db6.

     Use *note threading.get_ident(): 119e. or the *note ident: 2e33.
     attribute of *note threading.Thread: 956. objects to get a suitable
     value for 'thread_id'.

     If 'signalnum' is 0, then no signal is sent, but error checking is
     still performed; this can be used to check if the target thread is
     still running.

     Raises an *note auditing event: 1a15. ‘signal.pthread_kill’ with
     arguments ‘thread_id’, ‘signalnum’.

     *note Availability: 1ef7.: Unix.

     See the man page ‘pthread_kill(3)(11)’ for further information.

     See also *note os.kill(): 13b4.

     Added in version 3.3.

 -- Function: signal.pthread_sigmask (how, mask)

     Fetch and/or change the signal mask of the calling thread.  The
     signal mask is the set of signals whose delivery is currently
     blocked for the caller.  Return the old signal mask as a set of
     signals.

     The behavior of the call is dependent on the value of 'how', as
     follows.

        * *note SIG_BLOCK: 372f.: The set of blocked signals is the
          union of the current set and the 'mask' argument.

        * *note SIG_UNBLOCK: 3730.: The signals in 'mask' are removed
          from the current set of blocked signals.  It is permissible to
          attempt to unblock a signal which is not blocked.

        * *note SIG_SETMASK: 3731.: The set of blocked signals is set to
          the 'mask' argument.

     'mask' is a set of signal numbers (e.g.  {*note signal.SIGINT: 84a,
     *note signal.SIGTERM: 142d.}).  Use *note valid_signals(): 3741.
     for a full mask including all signals.

     For example, ‘signal.pthread_sigmask(signal.SIG_BLOCK, [])’ reads
     the signal mask of the calling thread.

     *note SIGKILL: b74. and *note SIGSTOP: 373b. cannot be blocked.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigprocmask(2)(12)’ and ‘pthread_sigmask(3)(13)’
     for further information.

     See also *note pause(): 3749, *note sigpending(): 1176. and *note
     sigwait(): 1177.

     Added in version 3.3.

 -- Function: signal.setitimer (which, seconds, interval=0.0)

     Sets given interval timer (one of *note signal.ITIMER_REAL: 3742,
     *note signal.ITIMER_VIRTUAL: 3743. or *note signal.ITIMER_PROF:
     3744.) specified by 'which' to fire after 'seconds' (float is
     accepted, different from *note alarm(): 3748.) and after that every
     'interval' seconds (if 'interval' is non-zero).  The interval timer
     specified by 'which' can be cleared by setting 'seconds' to zero.

     When an interval timer fires, a signal is sent to the process.  The
     signal sent is dependent on the timer being used; *note
     signal.ITIMER_REAL: 3742. will deliver *note SIGALRM: 3736, *note
     signal.ITIMER_VIRTUAL: 3743. sends *note SIGVTALRM: 373e, and *note
     signal.ITIMER_PROF: 3744. will deliver *note SIGPROF: 373a.

     The old values are returned as a tuple: (delay, interval).

     Attempting to pass an invalid interval timer will cause an *note
     ItimerError: 3745.

     *note Availability: 1ef7.: Unix.

 -- Function: signal.getitimer (which)

     Returns current value of a given interval timer specified by
     'which'.

     *note Availability: 1ef7.: Unix.

 -- Function: signal.set_wakeup_fd (fd, *, warn_on_full_buffer=True)

     Set the wakeup file descriptor to 'fd'.  When a signal your program
     has registered a signal handler for is received, the signal number
     is written as a single byte into the fd.  If you haven’t registered
     a signal handler for the signals you care about, then nothing will
     be written to the wakeup fd.  This can be used by a library to
     wakeup a poll or select call, allowing the signal to be fully
     processed.

     The old wakeup fd is returned (or -1 if file descriptor wakeup was
     not enabled).  If 'fd' is -1, file descriptor wakeup is disabled.
     If not -1, 'fd' must be non-blocking.  It is up to the library to
     remove any bytes from 'fd' before calling poll or select again.

     When threads are enabled, this function can only be called from
     *note the main thread of the main interpreter: 372d.; attempting to
     call it from other threads will cause a *note ValueError: 202.
     exception to be raised.

     There are two common ways to use this function.  In both
     approaches, you use the fd to wake up when a signal arrives, but
     then they differ in how they determine 'which' signal or signals
     have arrived.

     In the first approach, we read the data out of the fd’s buffer, and
     the byte values give you the signal numbers.  This is simple, but
     in rare cases it can run into a problem: generally the fd will have
     a limited amount of buffer space, and if too many signals arrive
     too quickly, then the buffer may become full, and some signals may
     be lost.  If you use this approach, then you should set
     ‘warn_on_full_buffer=True’, which will at least cause a warning to
     be printed to stderr when signals are lost.

     In the second approach, we use the wakeup fd 'only' for wakeups,
     and ignore the actual byte values.  In this case, all we care about
     is whether the fd’s buffer is empty or non-empty; a full buffer
     doesn’t indicate a problem at all.  If you use this approach, then
     you should set ‘warn_on_full_buffer=False’, so that your users are
     not confused by spurious warning messages.

     Changed in version 3.5: On Windows, the function now also supports
     socket handles.

     Changed in version 3.7: Added ‘warn_on_full_buffer’ parameter.

 -- Function: signal.siginterrupt (signalnum, flag)

     Change system call restart behaviour: if 'flag' is *note False:
     b4f, system calls will be restarted when interrupted by signal
     'signalnum', otherwise system calls will be interrupted.  Returns
     nothing.

     *note Availability: 1ef7.: Unix.

     See the man page ‘siginterrupt(3)(14)’ for further information.

     Note that installing a signal handler with *note signal(): c6. will
     reset the restart behaviour to interruptible by implicitly calling
     ‘siginterrupt()’ with a true 'flag' value for the given signal.

 -- Function: signal.signal (signalnum, handler)

     Set the handler for signal 'signalnum' to the function 'handler'.
     'handler' can be a callable Python object taking two arguments (see
     below), or one of the special values *note signal.SIG_IGN: 1956. or
     *note signal.SIG_DFL: 1957.  The previous signal handler will be
     returned (see the description of *note getsignal(): 17bd. above).
     (See the Unix man page ‘signal(2)(15)’ for further information.)

     When threads are enabled, this function can only be called from
     *note the main thread of the main interpreter: 372d.; attempting to
     call it from other threads will cause a *note ValueError: 202.
     exception to be raised.

     The 'handler' is called with two arguments: the signal number and
     the current stack frame (‘None’ or a frame object; for a
     description of frame objects, see the *note description in the type
     hierarchy: 6e3. or see the attribute descriptions in the *note
     inspect: 7e. module).

     On Windows, ‘signal()’ can only be called with *note SIGABRT: 10c0,
     *note SIGFPE: 10bf, *note SIGILL: 10c2, *note SIGINT: 84a, *note
     SIGSEGV: 10be, *note SIGTERM: 142d, or *note SIGBREAK: 3737.  A
     *note ValueError: 202. will be raised in any other case.  Note that
     not all systems define the same set of signal names; an *note
     AttributeError: 34e. will be raised if a signal name is not defined
     as ‘SIG*’ module level constant.

 -- Function: signal.sigpending ()

     Examine the set of signals that are pending for delivery to the
     calling thread (i.e., the signals which have been raised while
     blocked).  Return the set of the pending signals.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigpending(2)(16)’ for further information.

     See also *note pause(): 3749, *note pthread_sigmask(): 1174. and
     *note sigwait(): 1177.

     Added in version 3.3.

 -- Function: signal.sigwait (sigset)

     Suspend execution of the calling thread until the delivery of one
     of the signals specified in the signal set 'sigset'.  The function
     accepts the signal (removes it from the pending list of signals),
     and returns the signal number.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigwait(3)(17)’ for further information.

     See also *note pause(): 3749, *note pthread_sigmask(): 1174, *note
     sigpending(): 1176, *note sigwaitinfo(): dd9. and *note
     sigtimedwait(): dd8.

     Added in version 3.3.

 -- Function: signal.sigwaitinfo (sigset)

     Suspend execution of the calling thread until the delivery of one
     of the signals specified in the signal set 'sigset'.  The function
     accepts the signal and removes it from the pending list of signals.
     If one of the signals in 'sigset' is already pending for the
     calling thread, the function will return immediately with
     information about that signal.  The signal handler is not called
     for the delivered signal.  The function raises an *note
     InterruptedError: db6. if it is interrupted by a signal that is not
     in 'sigset'.

     The return value is an object representing the data contained in
     the ‘siginfo_t’ structure, namely: ‘si_signo’, ‘si_code’,
     ‘si_errno’, ‘si_pid’, ‘si_uid’, ‘si_status’, ‘si_band’.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigwaitinfo(2)(18)’ for further information.

     See also *note pause(): 3749, *note sigwait(): 1177. and *note
     sigtimedwait(): dd8.

     Added in version 3.3.

     Changed in version 3.5: The function is now retried if interrupted
     by a signal not in 'sigset' and the signal handler does not raise
     an exception (see PEP 475(19) for the rationale).

 -- Function: signal.sigtimedwait (sigset, timeout)

     Like *note sigwaitinfo(): dd9, but takes an additional 'timeout'
     argument specifying a timeout.  If 'timeout' is specified as ‘0’, a
     poll is performed.  Returns *note None: 678. if a timeout occurs.

     *note Availability: 1ef7.: Unix.

     See the man page ‘sigtimedwait(2)(20)’ for further information.

     See also *note pause(): 3749, *note sigwait(): 1177. and *note
     sigwaitinfo(): dd9.

     Added in version 3.3.

     Changed in version 3.5: The function is now retried with the
     recomputed 'timeout' if interrupted by a signal not in 'sigset' and
     the signal handler does not raise an exception (see PEP 475(21) for
     the rationale).

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/sigprocmask(2)

   (2) https://manpages.debian.org/pthread_sigmask(3)

   (3) https://manpages.debian.org/abort(3)

   (4) https://manpages.debian.org/alarm(2)

   (5) https://manpages.debian.org/signal(7)

   (6) https://manpages.debian.org/signal(2)

   (7) https://manpages.debian.org/signal(7)

   (8) https://manpages.debian.org/alarm(2)

   (9) https://manpages.debian.org/signal(2)

   (10) https://manpages.debian.org/pidfd_send_signal(2)

   (11) https://manpages.debian.org/pthread_kill(3)

   (12) https://manpages.debian.org/sigprocmask(2)

   (13) https://manpages.debian.org/pthread_sigmask(3)

   (14) https://manpages.debian.org/siginterrupt(3)

   (15) https://manpages.debian.org/signal(2)

   (16) https://manpages.debian.org/sigpending(2)

   (17) https://manpages.debian.org/sigwait(3)

   (18) https://manpages.debian.org/sigwaitinfo(2)

   (19) https://peps.python.org/pep-0475/

   (20) https://manpages.debian.org/sigtimedwait(2)

   (21) https://peps.python.org/pep-0475/


File: python.info,  Node: Examples<22>,  Next: Note on SIGPIPE,  Prev: Module contents<3>,  Up: signal — Set handlers for asynchronous events

5.19.6.5 Examples
.................

Here is a minimal example program.  It uses the *note alarm(): 3748.
function to limit the time spent waiting to open a file; this is useful
if the file is for a serial device that may not be turned on, which
would normally cause the *note os.open(): dc0. to hang indefinitely.
The solution is to set a 5-second alarm before opening the file; if the
operation takes too long, the alarm signal will be sent, and the handler
raises an exception.

     import signal, os

     def handler(signum, frame):
         signame = signal.Signals(signum).name
         print(f'Signal handler called with signal {signame} ({signum})')
         raise OSError("Couldn't open device!")

     # Set the signal handler and a 5-second alarm
     signal.signal(signal.SIGALRM, handler)
     signal.alarm(5)

     # This open() may hang indefinitely
     fd = os.open('/dev/ttyS0', os.O_RDWR)

     signal.alarm(0)          # Disable the alarm


File: python.info,  Node: Note on SIGPIPE,  Next: Note on Signal Handlers and Exceptions,  Prev: Examples<22>,  Up: signal — Set handlers for asynchronous events

5.19.6.6 Note on SIGPIPE
........................

Piping output of your program to tools like ‘head(1)(1)’ will cause a
*note SIGPIPE: 3729. signal to be sent to your process when the receiver
of its standard output closes early.  This results in an exception like
‘BrokenPipeError: [Errno 32] Broken pipe’.  To handle this case, wrap
your entry point to catch this exception as follows:

     import os
     import sys

     def main():
         try:
             # simulate large output (your code replaces this loop)
             for x in range(10000):
                 print("y")
             # flush output here to force SIGPIPE to be triggered
             # while inside this try block.
             sys.stdout.flush()
         except BrokenPipeError:
             # Python flushes standard streams on exit; redirect remaining output
             # to devnull to avoid another BrokenPipeError at shutdown
             devnull = os.open(os.devnull, os.O_WRONLY)
             os.dup2(devnull, sys.stdout.fileno())
             sys.exit(1)  # Python exits with error code 1 on EPIPE

     if __name__ == '__main__':
         main()

Do not set *note SIGPIPE: 3729.’s disposition to *note SIG_DFL: 1957. in
order to avoid *note BrokenPipeError: 109a.  Doing that would cause your
program to exit unexpectedly whenever any socket connection is
interrupted while your program is still writing to it.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/head(1)


File: python.info,  Node: Note on Signal Handlers and Exceptions,  Prev: Note on SIGPIPE,  Up: signal — Set handlers for asynchronous events

5.19.6.7 Note on Signal Handlers and Exceptions
...............................................

If a signal handler raises an exception, the exception will be
propagated to the main thread and may be raised after any *note
bytecode: 187. instruction.  Most notably, a *note KeyboardInterrupt:
9dc. may appear at any point during execution.  Most Python code,
including the standard library, cannot be made robust against this, and
so a ‘KeyboardInterrupt’ (or any other exception resulting from a signal
handler) may on rare occasions put the program in an unexpected state.

To illustrate this issue, consider the following code:

     class SpamContext:
         def __init__(self):
             self.lock = threading.Lock()

         def __enter__(self):
             # If KeyboardInterrupt occurs here, everything is fine
             self.lock.acquire()
             # If KeyboardInterrupt occurs here, __exit__ will not be called
             ...
             # KeyboardInterrupt could occur just before the function returns

         def __exit__(self, exc_type, exc_val, exc_tb):
             ...
             self.lock.release()

For many programs, especially those that merely want to exit on *note
KeyboardInterrupt: 9dc, this is not a problem, but applications that are
complex or require high reliability should avoid raising exceptions from
signal handlers.  They should also avoid catching ‘KeyboardInterrupt’ as
a means of gracefully shutting down.  Instead, they should install their
own *note SIGINT: 84a. handler.  Below is an example of an HTTP server
that avoids ‘KeyboardInterrupt’:

     import signal
     import socket
     from selectors import DefaultSelector, EVENT_READ
     from http.server import HTTPServer, SimpleHTTPRequestHandler

     interrupt_read, interrupt_write = socket.socketpair()

     def handler(signum, frame):
         print('Signal handler called with signal', signum)
         interrupt_write.send(b'\0')
     signal.signal(signal.SIGINT, handler)

     def serve_forever(httpd):
         sel = DefaultSelector()
         sel.register(interrupt_read, EVENT_READ)
         sel.register(httpd, EVENT_READ)

         while True:
             for key, _ in sel.select():
                 if key.fileobj == interrupt_read:
                     interrupt_read.recv(1)
                     return
                 if key.fileobj == httpd:
                     httpd.handle_request()

     print("Serving on port 8000")
     httpd = HTTPServer(('', 8000), SimpleHTTPRequestHandler)
     serve_forever(httpd)
     print("Shutdown...")


File: python.info,  Node: mmap — Memory-mapped file support,  Prev: signal — Set handlers for asynchronous events,  Up: Networking and Interprocess Communication

5.19.7 ‘mmap’ — Memory-mapped file support
------------------------------------------

__________________________________________________________________

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

Memory-mapped file objects behave like both *note bytearray: 2ea. and
like *note file objects: 1208.  You can use mmap objects in most places
where ‘bytearray’ are expected; for example, you can use the *note re:
b9. module to search through a memory-mapped file.  You can also change
a single byte by doing ‘obj[index] = 97’, or change a subsequence by
assigning to a slice: ‘obj[i1:i2] = b'...'’.  You can also read and
write data starting at the current file position, and ‘seek()’ through
the file to different positions.

A memory-mapped file is created by the *note mmap: 20b. constructor,
which is different on Unix and on Windows.  In either case you must
provide a file descriptor for a file opened for update.  If you wish to
map an existing Python file object, use its *note fileno(): 15f5. method
to obtain the correct value for the 'fileno' parameter.  Otherwise, you
can open the file using the *note os.open(): dc0. function, which
returns a file descriptor directly (the file still needs to be closed
when done).

     Note: If you want to create a memory-mapping for a writable,
     buffered file, you should *note flush(): 2db9. the file first.
     This is necessary to ensure that local modifications to the buffers
     are actually available to the mapping.

For both the Unix and Windows versions of the constructor, 'access' may
be specified as an optional keyword parameter.  'access' accepts one of
four values: ‘ACCESS_READ’, ‘ACCESS_WRITE’, or ‘ACCESS_COPY’ to specify
read-only, write-through or copy-on-write memory respectively, or
‘ACCESS_DEFAULT’ to defer to 'prot'.  'access' can be used on both Unix
and Windows.  If 'access' is not specified, Windows mmap returns a
write-through mapping.  The initial memory values for all three access
types are taken from the specified file.  Assignment to an ‘ACCESS_READ’
memory map raises a *note TypeError: 2c3. exception.  Assignment to an
‘ACCESS_WRITE’ memory map affects both memory and the underlying file.
Assignment to an ‘ACCESS_COPY’ memory map affects memory but does not
update the underlying file.

Changed in version 3.7: Added ‘ACCESS_DEFAULT’ constant.

To map anonymous memory, -1 should be passed as the fileno along with
the length.

 -- Class: mmap.mmap (fileno, length, tagname=None,
          access=ACCESS_DEFAULT, offset=0)

     '(Windows version)' Maps 'length' bytes from the file specified by
     the file handle 'fileno', and creates a mmap object.  If 'length'
     is larger than the current size of the file, the file is extended
     to contain 'length' bytes.  If 'length' is ‘0’, the maximum length
     of the map is the current size of the file, except that if the file
     is empty Windows raises an exception (you cannot create an empty
     mapping on Windows).

     'tagname', if specified and not ‘None’, is a string giving a tag
     name for the mapping.  Windows allows you to have many different
     mappings against the same file.  If you specify the name of an
     existing tag, that tag is opened, otherwise a new tag of this name
     is created.  If this parameter is omitted or ‘None’, the mapping is
     created without a name.  Avoiding the use of the 'tagname'
     parameter will assist in keeping your code portable between Unix
     and Windows.

     'offset' may be specified as a non-negative integer offset.  mmap
     references will be relative to the offset from the beginning of the
     file.  'offset' defaults to 0.  'offset' must be a multiple of the
     ‘ALLOCATIONGRANULARITY’.

     Raises an *note auditing event: 1a15. ‘mmap.__new__’ with arguments
     ‘fileno’, ‘length’, ‘access’, ‘offset’.

 -- Class: mmap.mmap (fileno, length, flags=MAP_SHARED, prot=PROT_WRITE
          | PROT_READ, access=ACCESS_DEFAULT, offset=0, *, trackfd=True)

     '(Unix version)' Maps 'length' bytes from the file specified by the
     file descriptor 'fileno', and returns a mmap object.  If 'length'
     is ‘0’, the maximum length of the map will be the current size of
     the file when *note mmap: 20b. is called.

     'flags' specifies the nature of the mapping.  *note MAP_PRIVATE:
     3751. creates a private copy-on-write mapping, so changes to the
     contents of the mmap object will be private to this process, and
     *note MAP_SHARED: 3752. creates a mapping that’s shared with all
     other processes mapping the same areas of the file.  The default
     value is ‘MAP_SHARED’.  Some systems have additional possible flags
     with the full list specified in *note MAP_* constants: 3753.

     'prot', if specified, gives the desired memory protection; the two
     most useful values are ‘PROT_READ’ and ‘PROT_WRITE’, to specify
     that the pages may be read or written.  'prot' defaults to
     ‘PROT_READ | PROT_WRITE’.

     'access' may be specified in lieu of 'flags' and 'prot' as an
     optional keyword parameter.  It is an error to specify both
     'flags', 'prot' and 'access'.  See the description of 'access'
     above for information on how to use this parameter.

     'offset' may be specified as a non-negative integer offset.  mmap
     references will be relative to the offset from the beginning of the
     file.  'offset' defaults to 0.  'offset' must be a multiple of
     ‘ALLOCATIONGRANULARITY’ which is equal to ‘PAGESIZE’ on Unix
     systems.

     If 'trackfd' is ‘False’, the file descriptor specified by 'fileno'
     will not be duplicated, and the resulting ‘mmap’ object will not be
     associated with the map’s underlying file.  This means that the
     *note size(): 3754. and *note resize(): 3755. methods will fail.
     This mode is useful to limit the number of open file descriptors.

     To ensure validity of the created memory mapping the file specified
     by the descriptor 'fileno' is internally automatically synchronized
     with the physical backing store on macOS.

     Changed in version 3.13: The 'trackfd' parameter was added.

     This example shows a simple way of using *note mmap: 20b.:

          import mmap

          # write a simple example file
          with open("hello.txt", "wb") as f:
              f.write(b"Hello Python!\n")

          with open("hello.txt", "r+b") as f:
              # memory-map the file, size 0 means whole file
              mm = mmap.mmap(f.fileno(), 0)
              # read content via standard file methods
              print(mm.readline())  # prints b"Hello Python!\n"
              # read content via slice notation
              print(mm[:5])  # prints b"Hello"
              # update content using slice notation;
              # note that new content must have same size
              mm[6:] = b" world!\n"
              # ... and read again using standard file methods
              mm.seek(0)
              print(mm.readline())  # prints b"Hello  world!\n"
              # close the map
              mm.close()

     *note mmap: 20b. can also be used as a context manager in a *note
     with: 5d5. statement:

          import mmap

          with mmap.mmap(-1, 13) as mm:
              mm.write(b"Hello world!")

     Added in version 3.2: Context manager support.

     The next example demonstrates how to create an anonymous map and
     exchange data between the parent and child processes:

          import mmap
          import os

          mm = mmap.mmap(-1, 13)
          mm.write(b"Hello world!")

          pid = os.fork()

          if pid == 0:  # In a child process
              mm.seek(0)
              print(mm.readline())

              mm.close()

     Raises an *note auditing event: 1a15. ‘mmap.__new__’ with arguments
     ‘fileno’, ‘length’, ‘access’, ‘offset’.

     Memory-mapped file objects support the following methods:

      -- Method: close ()

          Closes the mmap.  Subsequent calls to other methods of the
          object will result in a ValueError exception being raised.
          This will not close the open file.

      -- Attribute: closed

          ‘True’ if the file is closed.

          Added in version 3.2.

      -- Method: find (sub[, start[, end]])

          Returns the lowest index in the object where the subsequence
          'sub' is found, such that 'sub' is contained in the range
          ['start', 'end'].  Optional arguments 'start' and 'end' are
          interpreted as in slice notation.  Returns ‘-1’ on failure.

          Changed in version 3.5: Writable *note bytes-like object: d55.
          is now accepted.

      -- Method: flush ()

      -- Method: flush (offset, size, /)

          Flushes changes made to the in-memory copy of a file back to
          disk.  Without use of this call there is no guarantee that
          changes are written back before the object is destroyed.  If
          'offset' and 'size' are specified, only changes to the given
          range of bytes will be flushed to disk; otherwise, the whole
          extent of the mapping is flushed.  'offset' must be a multiple
          of the ‘PAGESIZE’ or ‘ALLOCATIONGRANULARITY’.

          ‘None’ is returned to indicate success.  An exception is
          raised when the call failed.

          Changed in version 3.8: Previously, a nonzero value was
          returned on success; zero was returned on error under Windows.
          A zero value was returned on success; an exception was raised
          on error under Unix.

      -- Method: madvise (option[, start[, length]])

          Send advice 'option' to the kernel about the memory region
          beginning at 'start' and extending 'length' bytes.  'option'
          must be one of the *note MADV_* constants: 3759. available on
          the system.  If 'start' and 'length' are omitted, the entire
          mapping is spanned.  On some systems (including Linux),
          'start' must be a multiple of the ‘PAGESIZE’.

          Availability: Systems with the ‘madvise()’ system call.

          Added in version 3.8.

      -- Method: move (dest, src, count)

          Copy the 'count' bytes starting at offset 'src' to the
          destination index 'dest'.  If the mmap was created with
          ‘ACCESS_READ’, then calls to move will raise a *note
          TypeError: 2c3. exception.

      -- Method: read ([n])

          Return a *note bytes: 1c2. containing up to 'n' bytes starting
          from the current file position.  If the argument is omitted,
          ‘None’ or negative, return all bytes from the current file
          position to the end of the mapping.  The file position is
          updated to point after the bytes that were returned.

          Changed in version 3.3: Argument can be omitted or ‘None’.

      -- Method: read_byte ()

          Returns a byte at the current file position as an integer, and
          advances the file position by 1.

      -- Method: readline ()

          Returns a single line, starting at the current file position
          and up to the next newline.  The file position is updated to
          point after the bytes that were returned.

      -- Method: resize (newsize)

          Resizes the map and the underlying file, if any.

          Resizing a map created with 'access' of ‘ACCESS_READ’ or
          ‘ACCESS_COPY’, will raise a *note TypeError: 2c3. exception.
          Resizing a map created with 'trackfd' set to ‘False’, will
          raise a *note ValueError: 202. exception.

          'On Windows': Resizing the map will raise an *note OSError:
          41a. if there are other maps against the same named file.
          Resizing an anonymous map (ie against the pagefile) will
          silently create a new map with the original data copied over
          up to the length of the new size.

          Changed in version 3.11: Correctly fails if attempting to
          resize when another map is held Allows resize against an
          anonymous map on Windows

      -- Method: rfind (sub[, start[, end]])

          Returns the highest index in the object where the subsequence
          'sub' is found, such that 'sub' is contained in the range
          ['start', 'end'].  Optional arguments 'start' and 'end' are
          interpreted as in slice notation.  Returns ‘-1’ on failure.

          Changed in version 3.5: Writable *note bytes-like object: d55.
          is now accepted.

      -- Method: seek (pos[, whence])

          Set the file’s current position.  'whence' argument is
          optional and defaults to ‘os.SEEK_SET’ or ‘0’ (absolute file
          positioning); other values are ‘os.SEEK_CUR’ or ‘1’ (seek
          relative to the current position) and ‘os.SEEK_END’ or ‘2’
          (seek relative to the file’s end).

          Changed in version 3.13: Return the new absolute position
          instead of ‘None’.

      -- Method: seekable ()

          Return whether the file supports seeking, and the return value
          is always ‘True’.

          Added in version 3.13.

      -- Method: size ()

          Return the length of the file, which can be larger than the
          size of the memory-mapped area.

      -- Method: tell ()

          Returns the current position of the file pointer.

      -- Method: write (bytes)

          Write the bytes in 'bytes' into memory at the current position
          of the file pointer and return the number of bytes written
          (never less than ‘len(bytes)’, since if the write fails, a
          *note ValueError: 202. will be raised).  The file position is
          updated to point after the bytes that were written.  If the
          mmap was created with ‘ACCESS_READ’, then writing to it will
          raise a *note TypeError: 2c3. exception.

          Changed in version 3.5: Writable *note bytes-like object: d55.
          is now accepted.

          Changed in version 3.6: The number of bytes written is now
          returned.

      -- Method: write_byte (byte)

          Write the integer 'byte' into memory at the current position
          of the file pointer; the file position is advanced by ‘1’.  If
          the mmap was created with ‘ACCESS_READ’, then writing to it
          will raise a *note TypeError: 2c3. exception.

* Menu:

* MADV_* Constants::
* MAP_* Constants::


File: python.info,  Node: MADV_* Constants,  Next: MAP_* Constants,  Up: mmap — Memory-mapped file support

5.19.7.1 MADV_* Constants
.........................

 -- Data: mmap.MADV_NORMAL
 -- Data: mmap.MADV_RANDOM
 -- Data: mmap.MADV_SEQUENTIAL
 -- Data: mmap.MADV_WILLNEED
 -- Data: mmap.MADV_DONTNEED
 -- Data: mmap.MADV_REMOVE
 -- Data: mmap.MADV_DONTFORK
 -- Data: mmap.MADV_DOFORK
 -- Data: mmap.MADV_HWPOISON
 -- Data: mmap.MADV_MERGEABLE
 -- Data: mmap.MADV_UNMERGEABLE
 -- Data: mmap.MADV_SOFT_OFFLINE
 -- Data: mmap.MADV_HUGEPAGE
 -- Data: mmap.MADV_NOHUGEPAGE
 -- Data: mmap.MADV_DONTDUMP
 -- Data: mmap.MADV_DODUMP
 -- Data: mmap.MADV_FREE
 -- Data: mmap.MADV_NOSYNC
 -- Data: mmap.MADV_AUTOSYNC
 -- Data: mmap.MADV_NOCORE
 -- Data: mmap.MADV_CORE
 -- Data: mmap.MADV_PROTECT
 -- Data: mmap.MADV_FREE_REUSABLE
 -- Data: mmap.MADV_FREE_REUSE

     These options can be passed to *note mmap.madvise(): a13.  Not
     every option will be present on every system.

     Availability: Systems with the madvise() system call.

     Added in version 3.8.


File: python.info,  Node: MAP_* Constants,  Prev: MADV_* Constants,  Up: mmap — Memory-mapped file support

5.19.7.2 MAP_* Constants
........................

 -- Data: mmap.MAP_SHARED
 -- Data: mmap.MAP_PRIVATE
 -- Data: mmap.MAP_32BIT
 -- Data: mmap.MAP_ALIGNED_SUPER
 -- Data: mmap.MAP_ANON
 -- Data: mmap.MAP_ANONYMOUS
 -- Data: mmap.MAP_CONCEAL
 -- Data: mmap.MAP_DENYWRITE
 -- Data: mmap.MAP_EXECUTABLE
 -- Data: mmap.MAP_HASSEMAPHORE
 -- Data: mmap.MAP_JIT
 -- Data: mmap.MAP_NOCACHE
 -- Data: mmap.MAP_NOEXTEND
 -- Data: mmap.MAP_NORESERVE
 -- Data: mmap.MAP_POPULATE
 -- Data: mmap.MAP_RESILIENT_CODESIGN
 -- Data: mmap.MAP_RESILIENT_MEDIA
 -- Data: mmap.MAP_STACK
 -- Data: mmap.MAP_TPRO
 -- Data: mmap.MAP_TRANSLATED_ALLOW_EXECUTE
 -- Data: mmap.MAP_UNIX03

     These are the various flags that can be passed to *note
     mmap.mmap(): 20b.  ‘MAP_ALIGNED_SUPER’ is only available at FreeBSD
     and ‘MAP_CONCEAL’ is only available at OpenBSD. Note that some
     options might not be present on some systems.

     Changed in version 3.10: Added ‘MAP_POPULATE’ constant.

     Added in version 3.11: Added ‘MAP_STACK’ constant.

     Added in version 3.12: Added ‘MAP_ALIGNED_SUPER’ and ‘MAP_CONCEAL’
     constants.

     Added in version 3.13: Added ‘MAP_32BIT’, ‘MAP_HASSEMAPHORE’,
     ‘MAP_JIT’, ‘MAP_NOCACHE’, ‘MAP_NOEXTEND’, ‘MAP_NORESERVE’,
     ‘MAP_RESILIENT_CODESIGN’, ‘MAP_RESILIENT_MEDIA’, ‘MAP_TPRO’,
     ‘MAP_TRANSLATED_ALLOW_EXECUTE’, and ‘MAP_UNIX03’ constants.


File: python.info,  Node: Internet Data Handling,  Next: Structured Markup Processing Tools,  Prev: Networking and Interprocess Communication,  Up: The Python Standard Library

5.20 Internet Data Handling
===========================

This chapter describes modules which support handling data formats
commonly used on the internet.

* Menu:

* email — An email and MIME handling package::
* json — JSON encoder and decoder::
* mailbox — Manipulate mailboxes in various formats::
* mimetypes — Map filenames to MIME types::
* base64 — Base16, Base32, Base64, Base85 Data Encodings: base64 — Base16 Base32 Base64 Base85 Data Encodings.
* binascii — Convert between binary and ASCII::
* quopri — Encode and decode MIME quoted-printable data::


File: python.info,  Node: email — An email and MIME handling package,  Next: json — JSON encoder and decoder,  Up: Internet Data Handling

5.20.1 ‘email’ — An email and MIME handling package
---------------------------------------------------

'Source code:' Lib/email/__init__.py(1)

__________________________________________________________________

The ‘email’ package is a library for managing email messages.  It is
specifically 'not' designed to do any sending of email messages to SMTP
( RFC 2821(2)), NNTP, or other servers; those are functions of modules
such as *note smtplib: ca.  The ‘email’ package attempts to be as
RFC-compliant as possible, supporting RFC 5322(3) and RFC 6532(4), as
well as such MIME-related RFCs as RFC 2045(5), RFC 2046(6), RFC 2047(7),
RFC 2183(8), and RFC 2231(9).

The overall structure of the email package can be divided into three
major components, plus a fourth component that controls the behavior of
the other components.

The central component of the package is an “object model” that
represents email messages.  An application interacts with the package
primarily through the object model interface defined in the *note
message: 44. sub-module.  The application can use this API to ask
questions about an existing email, to construct a new email, or to add
or remove email subcomponents that themselves use the same object model
interface.  That is, following the nature of email messages and their
MIME subcomponents, the email object model is a tree structure of
objects that all provide the *note EmailMessage: 27b. API.

The other two major components of the package are the *note parser: 4e.
and the *note generator: 40.  The parser takes the serialized version of
an email message (a stream of bytes) and converts it into a tree of
*note EmailMessage: 27b. objects.  The generator takes an ‘EmailMessage’
and turns it back into a serialized byte stream.  (The parser and
generator also handle streams of text characters, but this usage is
discouraged as it is too easy to end up with messages that are not valid
in one way or another.)

The control component is the *note policy: 4f. module.  Every *note
EmailMessage: 27b, every *note generator: 40, and every *note parser:
4e. has an associated ‘policy’ object that controls its behavior.
Usually an application only needs to specify the policy when an
‘EmailMessage’ is created, either by directly instantiating an
‘EmailMessage’ to create a new email, or by parsing an input stream
using a ‘parser’.  But the policy can be changed when the message is
serialized using a ‘generator’.  This allows, for example, a generic
email message to be parsed from disk, but to serialize it using standard
SMTP settings when sending it to an email server.

The email package does its best to hide the details of the various
governing RFCs from the application.  Conceptually the application
should be able to treat the email message as a structured tree of
unicode text and binary attachments, without having to worry about how
these are represented when serialized.  In practice, however, it is
often necessary to be aware of at least some of the rules governing MIME
messages and their structure, specifically the names and nature of the
MIME “content types” and how they identify multipart documents.  For the
most part this knowledge should only be required for more complex
applications, and even then it should only be the high level structure
in question, and not the details of how those structures are
represented.  Since MIME content types are used widely in modern
internet software (not just email), this will be a familiar concept to
many programmers.

The following sections describe the functionality of the ‘email’
package.  We start with the *note message: 44. object model, which is
the primary interface an application will use, and follow that with the
*note parser: 4e. and *note generator: 40. components.  Then we cover
the *note policy: 4f. controls, which completes the treatment of the
main components of the library.

The next three sections cover the exceptions the package may raise and
the defects (non-compliance with the RFCs) that the *note parser: 4e.
may detect.  Then we cover the *note headerregistry: 42. and the *note
contentmanager: 3d. sub-components, which provide tools for doing more
detailed manipulation of headers and payloads, respectively.  Both of
these components contain features relevant to consuming and producing
non-trivial messages, but also document their extensibility APIs, which
will be of interest to advanced applications.

Following those is a set of examples of using the fundamental parts of
the APIs covered in the preceding sections.

The foregoing represent the modern (unicode friendly) API of the email
package.  The remaining sections, starting with the *note Message: 27c.
class, cover the legacy *note compat32: cbe. API that deals much more
directly with the details of how email messages are represented.  The
‘compat32’ API does 'not' hide the details of the RFCs from the
application, but for applications that need to operate at that level,
they can be useful tools.  This documentation is also relevant for
applications that are still using the *note compat32: cbe. API for
backward compatibility reasons.

Changed in version 3.6: Docs reorganized and rewritten to promote the
new *note EmailMessage: 27b./*note EmailPolicy: 10fb. API.

Contents of the ‘email’ package documentation:

* Menu:

* email.message; Representing an email message: email message Representing an email message.
* email.parser; Parsing email messages: email parser Parsing email messages.
* email.generator; Generating MIME documents: email generator Generating MIME documents.
* email.policy; Policy Objects: email policy Policy Objects.
* email.errors; Exception and Defect classes: email errors Exception and Defect classes.
* email.headerregistry; Custom Header Objects: email headerregistry Custom Header Objects.
* email.contentmanager; Managing MIME Content: email contentmanager Managing MIME Content.
* email; Examples: email Examples.
* email.message.Message; Representing an email message using the compat32 API: email message Message Representing an email message using the compat32 API.
* email.mime; Creating email and MIME objects from scratch: email mime Creating email and MIME objects from scratch.
* email.header; Internationalized headers: email header Internationalized headers.
* email.charset; Representing character sets: email charset Representing character sets.
* email.encoders; Encoders: email encoders Encoders.
* email.utils; Miscellaneous utilities: email utils Miscellaneous utilities.
* email.iterators; Iterators: email iterators Iterators.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/__init__.py

   (2) https://datatracker.ietf.org/doc/html/rfc2821.html

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html

   (4) https://datatracker.ietf.org/doc/html/rfc6532.html

   (5) https://datatracker.ietf.org/doc/html/rfc2045.html

   (6) https://datatracker.ietf.org/doc/html/rfc2046.html

   (7) https://datatracker.ietf.org/doc/html/rfc2047.html

   (8) https://datatracker.ietf.org/doc/html/rfc2183.html

   (9) https://datatracker.ietf.org/doc/html/rfc2231.html


File: python.info,  Node: email message Representing an email message,  Next: email parser Parsing email messages,  Up: email — An email and MIME handling package

5.20.1.1 ‘email.message’: Representing an email message
.......................................................

'Source code:' Lib/email/message.py(1)

__________________________________________________________________

Added in version 3.6: (2)

The central class in the *note email: 3b. package is the *note
EmailMessage: 27b. class, imported from the ‘email.message’ module.  It
is the base class for the ‘email’ object model.  ‘EmailMessage’ provides
the core functionality for setting and querying header fields, for
accessing message bodies, and for creating or modifying structured
messages.

An email message consists of 'headers' and a 'payload' (which is also
referred to as the 'content').  Headers are RFC 5322(3) or RFC 6532(4)
style field names and values, where the field name and value are
separated by a colon.  The colon is not part of either the field name or
the field value.  The payload may be a simple text message, or a binary
object, or a structured sequence of sub-messages each with their own set
of headers and their own payload.  The latter type of payload is
indicated by the message having a MIME type such as ‘multipart/*’ or
‘message/rfc822’.

The conceptual model provided by an *note EmailMessage: 27b. object is
that of an ordered dictionary of headers coupled with a 'payload' that
represents the RFC 5322(5) body of the message, which might be a list of
sub-‘EmailMessage’ objects.  In addition to the normal dictionary
methods for accessing the header names and values, there are methods for
accessing specialized information from the headers (for example the MIME
content type), for operating on the payload, for generating a serialized
version of the message, and for recursively walking over the object
tree.

The *note EmailMessage: 27b. dictionary-like interface is indexed by the
header names, which must be ASCII values.  The values of the dictionary
are strings with some extra methods.  Headers are stored and returned in
case-preserving form, but field names are matched case-insensitively.
The keys are ordered, but unlike a real dict, there can be duplicates.
Additional methods are provided for working with headers that have
duplicate keys.

The 'payload' is either a string or bytes object, in the case of simple
message objects, or a list of *note EmailMessage: 27b. objects, for MIME
container documents such as ‘multipart/*’ and ‘message/rfc822’ message
objects.

 -- Class: email.message.EmailMessage (policy=default)

     If 'policy' is specified use the rules it specifies to update and
     serialize the representation of the message.  If 'policy' is not
     set, use the *note default: 15d1. policy, which follows the rules
     of the email RFCs except for line endings (instead of the RFC
     mandated ‘\r\n’, it uses the Python standard ‘\n’ line endings).
     For more information see the *note policy: 4f. documentation.  (6)

      -- Method: as_string (unixfrom=False, maxheaderlen=None,
               policy=None)

          Return the entire message flattened as a string.  When
          optional 'unixfrom' is true, the envelope header is included
          in the returned string.  'unixfrom' defaults to ‘False’.  For
          backward compatibility with the base *note Message: 27c. class
          'maxheaderlen' is accepted, but defaults to ‘None’, which
          means that by default the line length is controlled by the
          *note max_line_length: 3789. of the policy.  The 'policy'
          argument may be used to override the default policy obtained
          from the message instance.  This can be used to control some
          of the formatting produced by the method, since the specified
          'policy' will be passed to the *note Generator: 1213.

          Flattening the message may trigger changes to the
          ‘EmailMessage’ if defaults need to be filled in to complete
          the transformation to a string (for example, MIME boundaries
          may be generated or modified).

          Note that this method is provided as a convenience and may not
          be the most useful way to serialize messages in your
          application, especially if you are dealing with multiple
          messages.  See *note email.generator.Generator: 1213. for a
          more flexible API for serializing messages.  Note also that
          this method is restricted to producing messages serialized as
          “7 bit clean” when *note utf8: e2a. is ‘False’, which is the
          default.

          Changed in version 3.6: the default behavior when
          'maxheaderlen' is not specified was changed from defaulting to
          0 to defaulting to the value of 'max_line_length' from the
          policy.

      -- Method: __str__ ()

          Equivalent to
          ‘as_string(policy=self.policy.clone(utf8=True))’.  Allows
          ‘str(msg)’ to produce a string containing the serialized
          message in a readable format.

          Changed in version 3.4: the method was changed to use
          ‘utf8=True’, thus producing an RFC 6531(7)-like message
          representation, instead of being a direct alias for *note
          as_string(): 3788.

      -- Method: as_bytes (unixfrom=False, policy=None)

          Return the entire message flattened as a bytes object.  When
          optional 'unixfrom' is true, the envelope header is included
          in the returned string.  'unixfrom' defaults to ‘False’.  The
          'policy' argument may be used to override the default policy
          obtained from the message instance.  This can be used to
          control some of the formatting produced by the method, since
          the specified 'policy' will be passed to the *note
          BytesGenerator: 1214.

          Flattening the message may trigger changes to the
          ‘EmailMessage’ if defaults need to be filled in to complete
          the transformation to a string (for example, MIME boundaries
          may be generated or modified).

          Note that this method is provided as a convenience and may not
          be the most useful way to serialize messages in your
          application, especially if you are dealing with multiple
          messages.  See *note email.generator.BytesGenerator: 1214. for
          a more flexible API for serializing messages.

      -- Method: __bytes__ ()

          Equivalent to *note as_bytes(): 378b.  Allows ‘bytes(msg)’ to
          produce a bytes object containing the serialized message.

      -- Method: is_multipart ()

          Return ‘True’ if the message’s payload is a list of
          sub-‘EmailMessage’ objects, otherwise return ‘False’.  When
          ‘is_multipart()’ returns ‘False’, the payload should be a
          string object (which might be a CTE encoded binary payload).
          Note that ‘is_multipart()’ returning ‘True’ does not
          necessarily mean that “msg.get_content_maintype() ==
          ‘multipart’” will return the ‘True’.  For example,
          ‘is_multipart’ will return ‘True’ when the ‘EmailMessage’ is
          of type ‘message/rfc822’.

      -- Method: set_unixfrom (unixfrom)

          Set the message’s envelope header to 'unixfrom', which should
          be a string.  (See *note mboxMessage: 378f. for a brief
          description of this header.)

      -- Method: get_unixfrom ()

          Return the message’s envelope header.  Defaults to ‘None’ if
          the envelope header was never set.

     The following methods implement the mapping-like interface for
     accessing the message’s headers.  Note that there are some semantic
     differences between these methods and a normal mapping (i.e.
     dictionary) interface.  For example, in a dictionary there are no
     duplicate keys, but here there may be duplicate message headers.
     Also, in dictionaries there is no guaranteed order to the keys
     returned by *note keys(): 3791, but in an ‘EmailMessage’ object,
     headers are always returned in the order they appeared in the
     original message, or in which they were added to the message later.
     Any header deleted and then re-added is always appended to the end
     of the header list.

     These semantic differences are intentional and are biased toward
     convenience in the most common use cases.

     Note that in all cases, any envelope header present in the message
     is not included in the mapping interface.

      -- Method: __len__ ()

          Return the total number of headers, including duplicates.

      -- Method: __contains__ (name)

          Return ‘True’ if the message object has a field named 'name'.
          Matching is done without regard to case and 'name' does not
          include the trailing colon.  Used for the ‘in’ operator.  For
          example:

               if 'message-id' in myMessage:
                  print('Message-ID:', myMessage['message-id'])

      -- Method: __getitem__ (name)

          Return the value of the named header field.  'name' does not
          include the colon field separator.  If the header is missing,
          ‘None’ is returned; a *note KeyError: 345. is never raised.

          Note that if the named field appears more than once in the
          message’s headers, exactly which of those field values will be
          returned is undefined.  Use the *note get_all(): 3795. method
          to get the values of all the extant headers named 'name'.

          Using the standard (non-‘compat32’) policies, the returned
          value is an instance of a subclass of *note
          email.headerregistry.BaseHeader: 3796.

      -- Method: __setitem__ (name, val)

          Add a header to the message with field name 'name' and value
          'val'.  The field is appended to the end of the message’s
          existing headers.

          Note that this does 'not' overwrite or delete any existing
          header with the same name.  If you want to ensure that the new
          header is the only one present in the message with field name
          'name', delete the field first, e.g.:

               del msg['subject']
               msg['subject'] = 'Python roolz!'

          If the *note policy: 4f. defines certain headers to be unique
          (as the standard policies do), this method may raise a *note
          ValueError: 202. when an attempt is made to assign a value to
          such a header when one already exists.  This behavior is
          intentional for consistency’s sake, but do not depend on it as
          we may choose to make such assignments do an automatic
          deletion of the existing header in the future.

      -- Method: __delitem__ (name)

          Delete all occurrences of the field with name 'name' from the
          message’s headers.  No exception is raised if the named field
          isn’t present in the headers.

      -- Method: keys ()

          Return a list of all the message’s header field names.

      -- Method: values ()

          Return a list of all the message’s field values.

      -- Method: items ()

          Return a list of 2-tuples containing all the message’s field
          headers and values.

      -- Method: get (name, failobj=None)

          Return the value of the named header field.  This is identical
          to *note __getitem__(): 283. except that optional 'failobj' is
          returned if the named header is missing ('failobj' defaults to
          ‘None’).

     Here are some additional useful header related methods:

      -- Method: get_all (name, failobj=None)

          Return a list of all the values for the field named 'name'.
          If there are no such named headers in the message, 'failobj'
          is returned (defaults to ‘None’).

      -- Method: add_header (_name, _value, **_params)

          Extended header setting.  This method is similar to *note
          __setitem__(): 3797. except that additional header parameters
          can be provided as keyword arguments.  '_name' is the header
          field to add and '_value' is the 'primary' value for the
          header.

          For each item in the keyword argument dictionary '_params',
          the key is taken as the parameter name, with underscores
          converted to dashes (since dashes are illegal in Python
          identifiers).  Normally, the parameter will be added as
          ‘key="value"’ unless the value is ‘None’, in which case only
          the key will be added.

          If the value contains non-ASCII characters, the charset and
          language may be explicitly controlled by specifying the value
          as a three tuple in the format ‘(CHARSET, LANGUAGE, VALUE)’,
          where ‘CHARSET’ is a string naming the charset to be used to
          encode the value, ‘LANGUAGE’ can usually be set to ‘None’ or
          the empty string (see RFC 2231(8) for other possibilities),
          and ‘VALUE’ is the string value containing non-ASCII code
          points.  If a three tuple is not passed and the value contains
          non-ASCII characters, it is automatically encoded in RFC
          2231(9) format using a ‘CHARSET’ of ‘utf-8’ and a ‘LANGUAGE’
          of ‘None’.

          Here is an example:

               msg.add_header('Content-Disposition', 'attachment', filename='bud.gif')

          This will add a header that looks like

               Content-Disposition: attachment; filename="bud.gif"

          An example of the extended interface with non-ASCII
          characters:

               msg.add_header('Content-Disposition', 'attachment',
                              filename=('iso-8859-1', '', 'Fußballer.ppt'))

      -- Method: replace_header (_name, _value)

          Replace a header.  Replace the first header found in the
          message that matches '_name', retaining header order and field
          name case of the original header.  If no matching header is
          found, raise a *note KeyError: 345.

      -- Method: get_content_type ()

          Return the message’s content type, coerced to lower case of
          the form ‘maintype/subtype’.  If there is no ‘Content-Type’
          header in the message return the value returned by *note
          get_default_type(): 379f.  If the ‘Content-Type’ header is
          invalid, return ‘text/plain’.

          (According to RFC 2045(10), messages always have a default
          type, ‘get_content_type()’ will always return a value.  RFC
          2045(11) defines a message’s default type to be ‘text/plain’
          unless it appears inside a ‘multipart/digest’ container, in
          which case it would be ‘message/rfc822’.  If the
          ‘Content-Type’ header has an invalid type specification, RFC
          2045(12) mandates that the default type be ‘text/plain’.)

      -- Method: get_content_maintype ()

          Return the message’s main content type.  This is the
          ‘maintype’ part of the string returned by *note
          get_content_type(): 379e.

      -- Method: get_content_subtype ()

          Return the message’s sub-content type.  This is the ‘subtype’
          part of the string returned by *note get_content_type(): 379e.

      -- Method: get_default_type ()

          Return the default content type.  Most messages have a default
          content type of ‘text/plain’, except for messages that are
          subparts of ‘multipart/digest’ containers.  Such subparts have
          a default content type of ‘message/rfc822’.

      -- Method: set_default_type (ctype)

          Set the default content type.  'ctype' should either be
          ‘text/plain’ or ‘message/rfc822’, although this is not
          enforced.  The default content type is not stored in the
          ‘Content-Type’ header, so it only affects the return value of
          the ‘get_content_type’ methods when no ‘Content-Type’ header
          is present in the message.

      -- Method: set_param (param, value, header='Content-Type',
               requote=True, charset=None, language='', replace=False)

          Set a parameter in the ‘Content-Type’ header.  If the
          parameter already exists in the header, replace its value with
          'value'.  When 'header' is ‘Content-Type’ (the default) and
          the header does not yet exist in the message, add it, set its
          value to ‘text/plain’, and append the new parameter value.
          Optional 'header' specifies an alternative header to
          ‘Content-Type’.

          If the value contains non-ASCII characters, the charset and
          language may be explicitly specified using the optional
          'charset' and 'language' parameters.  Optional 'language'
          specifies the RFC 2231(13) language, defaulting to the empty
          string.  Both 'charset' and 'language' should be strings.  The
          default is to use the ‘utf8’ 'charset' and ‘None’ for the
          'language'.

          If 'replace' is ‘False’ (the default) the header is moved to
          the end of the list of headers.  If 'replace' is ‘True’, the
          header will be updated in place.

          Use of the 'requote' parameter with ‘EmailMessage’ objects is
          deprecated.

          Note that existing parameter values of headers may be accessed
          through the *note params: 37a4. attribute of the header value
          (for example, ‘msg['Content-Type'].params['charset']’).

          Changed in version 3.4: ‘replace’ keyword was added.

      -- Method: del_param (param, header='content-type', requote=True)

          Remove the given parameter completely from the ‘Content-Type’
          header.  The header will be re-written in place without the
          parameter or its value.  Optional 'header' specifies an
          alternative to ‘Content-Type’.

          Use of the 'requote' parameter with ‘EmailMessage’ objects is
          deprecated.

      -- Method: get_filename (failobj=None)

          Return the value of the ‘filename’ parameter of the
          ‘Content-Disposition’ header of the message.  If the header
          does not have a ‘filename’ parameter, this method falls back
          to looking for the ‘name’ parameter on the ‘Content-Type’
          header.  If neither is found, or the header is missing, then
          'failobj' is returned.  The returned string will always be
          unquoted as per *note email.utils.unquote(): 37a7.

      -- Method: get_boundary (failobj=None)

          Return the value of the ‘boundary’ parameter of the
          ‘Content-Type’ header of the message, or 'failobj' if either
          the header is missing, or has no ‘boundary’ parameter.  The
          returned string will always be unquoted as per *note
          email.utils.unquote(): 37a7.

      -- Method: set_boundary (boundary)

          Set the ‘boundary’ parameter of the ‘Content-Type’ header to
          'boundary'.  ‘set_boundary()’ will always quote 'boundary' if
          necessary.  A *note HeaderParseError: 37aa. is raised if the
          message object has no ‘Content-Type’ header.

          Note that using this method is subtly different from deleting
          the old ‘Content-Type’ header and adding a new one with the
          new boundary via *note add_header(): 379c, because
          ‘set_boundary()’ preserves the order of the ‘Content-Type’
          header in the list of headers.

      -- Method: get_content_charset (failobj=None)

          Return the ‘charset’ parameter of the ‘Content-Type’ header,
          coerced to lower case.  If there is no ‘Content-Type’ header,
          or if that header has no ‘charset’ parameter, 'failobj' is
          returned.

      -- Method: get_charsets (failobj=None)

          Return a list containing the character set names in the
          message.  If the message is a ‘multipart’, then the list will
          contain one element for each subpart in the payload,
          otherwise, it will be a list of length 1.

          Each item in the list will be a string which is the value of
          the ‘charset’ parameter in the ‘Content-Type’ header for the
          represented subpart.  If the subpart has no ‘Content-Type’
          header, no ‘charset’ parameter, or is not of the ‘text’ main
          MIME type, then that item in the returned list will be
          'failobj'.

      -- Method: is_attachment ()

          Return ‘True’ if there is a ‘Content-Disposition’ header and
          its (case insensitive) value is ‘attachment’, ‘False’
          otherwise.

          Changed in version 3.4.2: is_attachment is now a method
          instead of a property, for consistency with *note
          is_multipart(): 37ae.

      -- Method: get_content_disposition ()

          Return the lowercased value (without parameters) of the
          message’s ‘Content-Disposition’ header if it has one, or
          ‘None’.  The possible values for this method are 'inline',
          'attachment' or ‘None’ if the message follows RFC 2183(14).

          Added in version 3.5.

     The following methods relate to interrogating and manipulating the
     content (payload) of the message.

      -- Method: walk ()

          The ‘walk()’ method is an all-purpose generator which can be
          used to iterate over all the parts and subparts of a message
          object tree, in depth-first traversal order.  You will
          typically use ‘walk()’ as the iterator in a ‘for’ loop; each
          iteration returns the next subpart.

          Here’s an example that prints the MIME type of every part of a
          multipart message structure:

               >>> for part in msg.walk():
               ...     print(part.get_content_type())
               multipart/report
               text/plain
               message/delivery-status
               text/plain
               text/plain
               message/rfc822
               text/plain

          ‘walk’ iterates over the subparts of any part where *note
          is_multipart(): 378d. returns ‘True’, even though
          ‘msg.get_content_maintype() == 'multipart'’ may return
          ‘False’.  We can see this in our example by making use of the
          ‘_structure’ debug helper function:

               >>> from email.iterators import _structure
               >>> for part in msg.walk():
               ...     print(part.get_content_maintype() == 'multipart',
               ...           part.is_multipart())
               True True
               False False
               False True
               False False
               False False
               False True
               False False
               >>> _structure(msg)
               multipart/report
                   text/plain
                   message/delivery-status
                       text/plain
                       text/plain
                   message/rfc822
                       text/plain

          Here the ‘message’ parts are not ‘multiparts’, but they do
          contain subparts.  ‘is_multipart()’ returns ‘True’ and ‘walk’
          descends into the subparts.

      -- Method: get_body (preferencelist=('related', 'html', 'plain'))

          Return the MIME part that is the best candidate to be the
          “body” of the message.

          'preferencelist' must be a sequence of strings from the set
          ‘related’, ‘html’, and ‘plain’, and indicates the order of
          preference for the content type of the part returned.

          Start looking for candidate matches with the object on which
          the ‘get_body’ method is called.

          If ‘related’ is not included in 'preferencelist', consider the
          root part (or subpart of the root part) of any related
          encountered as a candidate if the (sub-)part matches a
          preference.

          When encountering a ‘multipart/related’, check the ‘start’
          parameter and if a part with a matching ‘Content-ID’ is found,
          consider only it when looking for candidate matches.
          Otherwise consider only the first (default root) part of the
          ‘multipart/related’.

          If a part has a ‘Content-Disposition’ header, only consider
          the part a candidate match if the value of the header is
          ‘inline’.

          If none of the candidates matches any of the preferences in
          'preferencelist', return ‘None’.

          Notes: (1) For most applications the only 'preferencelist'
          combinations that really make sense are ‘('plain',)’,
          ‘('html', 'plain')’, and the default ‘('related', 'html',
          'plain')’.  (2) Because matching starts with the object on
          which ‘get_body’ is called, calling ‘get_body’ on a
          ‘multipart/related’ will return the object itself unless
          'preferencelist' has a non-default value.  (3) Messages (or
          message parts) that do not specify a ‘Content-Type’ or whose
          ‘Content-Type’ header is invalid will be treated as if they
          are of type ‘text/plain’, which may occasionally cause
          ‘get_body’ to return unexpected results.

      -- Method: iter_attachments ()

          Return an iterator over all of the immediate sub-parts of the
          message that are not candidate “body” parts.  That is, skip
          the first occurrence of each of ‘text/plain’, ‘text/html’,
          ‘multipart/related’, or ‘multipart/alternative’ (unless they
          are explicitly marked as attachments via ‘Content-Disposition:
          attachment’), and return all remaining parts.  When applied
          directly to a ‘multipart/related’, return an iterator over the
          all the related parts except the root part (ie: the part
          pointed to by the ‘start’ parameter, or the first part if
          there is no ‘start’ parameter or the ‘start’ parameter doesn’t
          match the ‘Content-ID’ of any of the parts).  When applied
          directly to a ‘multipart/alternative’ or a non-‘multipart’,
          return an empty iterator.

      -- Method: iter_parts ()

          Return an iterator over all of the immediate sub-parts of the
          message, which will be empty for a non-‘multipart’.  (See also
          *note walk(): 37b0.)

      -- Method: get_content (*args, content_manager=None, **kw)

          Call the *note get_content(): 37b5. method of the
          'content_manager', passing self as the message object, and
          passing along any other arguments or keywords as additional
          arguments.  If 'content_manager' is not specified, use the
          ‘content_manager’ specified by the current *note policy: 4f.

      -- Method: set_content (*args, content_manager=None, **kw)

          Call the *note set_content(): 37b6. method of the
          'content_manager', passing self as the message object, and
          passing along any other arguments or keywords as additional
          arguments.  If 'content_manager' is not specified, use the
          ‘content_manager’ specified by the current *note policy: 4f.

      -- Method: make_related (boundary=None)

          Convert a non-‘multipart’ message into a ‘multipart/related’
          message, moving any existing ‘Content-’ headers and payload
          into a (new) first part of the ‘multipart’.  If 'boundary' is
          specified, use it as the boundary string in the multipart,
          otherwise leave the boundary to be automatically created when
          it is needed (for example, when the message is serialized).

      -- Method: make_alternative (boundary=None)

          Convert a non-‘multipart’ or a ‘multipart/related’ into a
          ‘multipart/alternative’, moving any existing ‘Content-’
          headers and payload into a (new) first part of the
          ‘multipart’.  If 'boundary' is specified, use it as the
          boundary string in the multipart, otherwise leave the boundary
          to be automatically created when it is needed (for example,
          when the message is serialized).

      -- Method: make_mixed (boundary=None)

          Convert a non-‘multipart’, a ‘multipart/related’, or a
          ‘multipart-alternative’ into a ‘multipart/mixed’, moving any
          existing ‘Content-’ headers and payload into a (new) first
          part of the ‘multipart’.  If 'boundary' is specified, use it
          as the boundary string in the multipart, otherwise leave the
          boundary to be automatically created when it is needed (for
          example, when the message is serialized).

      -- Method: add_related (*args, content_manager=None, **kw)

          If the message is a ‘multipart/related’, create a new message
          object, pass all of the arguments to its *note set_content():
          1a03. method, and *note attach(): 37bb. it to the ‘multipart’.
          If the message is a non-‘multipart’, call *note
          make_related(): 37b7. and then proceed as above.  If the
          message is any other type of ‘multipart’, raise a *note
          TypeError: 2c3.  If 'content_manager' is not specified, use
          the ‘content_manager’ specified by the current *note policy:
          4f.  If the added part has no ‘Content-Disposition’ header,
          add one with the value ‘inline’.

      -- Method: add_alternative (*args, content_manager=None, **kw)

          If the message is a ‘multipart/alternative’, create a new
          message object, pass all of the arguments to its *note
          set_content(): 1a03. method, and *note attach(): 37bb. it to
          the ‘multipart’.  If the message is a non-‘multipart’ or
          ‘multipart/related’, call *note make_alternative(): 37b8. and
          then proceed as above.  If the message is any other type of
          ‘multipart’, raise a *note TypeError: 2c3.  If
          'content_manager' is not specified, use the ‘content_manager’
          specified by the current *note policy: 4f.

      -- Method: add_attachment (*args, content_manager=None, **kw)

          If the message is a ‘multipart/mixed’, create a new message
          object, pass all of the arguments to its *note set_content():
          1a03. method, and *note attach(): 37bb. it to the ‘multipart’.
          If the message is a non-‘multipart’, ‘multipart/related’, or
          ‘multipart/alternative’, call *note make_mixed(): 37b9. and
          then proceed as above.  If 'content_manager' is not specified,
          use the ‘content_manager’ specified by the current *note
          policy: 4f.  If the added part has no ‘Content-Disposition’
          header, add one with the value ‘attachment’.  This method can
          be used both for explicit attachments (‘Content-Disposition:
          attachment’) and ‘inline’ attachments (‘Content-Disposition:
          inline’), by passing appropriate options to the
          ‘content_manager’.

      -- Method: clear ()

          Remove the payload and all of the headers.

      -- Method: clear_content ()

          Remove the payload and all of the ‘!Content-’ headers, leaving
          all other headers intact and in their original order.

     ‘EmailMessage’ objects have the following instance attributes:

      -- Attribute: preamble

          The format of a MIME document allows for some text between the
          blank line following the headers, and the first multipart
          boundary string.  Normally, this text is never visible in a
          MIME-aware mail reader because it falls outside the standard
          MIME armor.  However, when viewing the raw text of the
          message, or when viewing the message in a non-MIME aware
          reader, this text can become visible.

          The 'preamble' attribute contains this leading extra-armor
          text for MIME documents.  When the *note Parser: 11e1.
          discovers some text after the headers but before the first
          boundary string, it assigns this text to the message’s
          'preamble' attribute.  When the *note Generator: 1213. is
          writing out the plain text representation of a MIME message,
          and it finds the message has a 'preamble' attribute, it will
          write this text in the area between the headers and the first
          boundary.  See *note email.parser: 4e. and *note
          email.generator: 40. for details.

          Note that if the message object has no preamble, the
          'preamble' attribute will be ‘None’.

      -- Attribute: epilogue

          The 'epilogue' attribute acts the same way as the 'preamble'
          attribute, except that it contains text that appears between
          the last boundary and the end of the message.  As with the
          *note preamble: 37c0, if there is no epilog text this
          attribute will be ‘None’.

      -- Attribute: defects

          The 'defects' attribute contains a list of all the problems
          found when parsing this message.  See *note email.errors: 3f.
          for a detailed description of the possible parsing defects.

 -- Class: email.message.MIMEPart (policy=default)

     This class represents a subpart of a MIME message.  It is identical
     to *note EmailMessage: 27b, except that no ‘MIME-Version’ headers
     are added when *note set_content(): 1a03. is called, since
     sub-parts do not need their own ‘MIME-Version’ headers.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/message.py

   (2) Originally added in 3.4 as a *note provisional module: 107f.
Docs for legacy message class moved to *note email.message.Message;
Representing an email message using the compat32 API: 3787.

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html

   (4) https://datatracker.ietf.org/doc/html/rfc6532.html

   (5) https://datatracker.ietf.org/doc/html/rfc5322.html

   (6) The *note EmailMessage: 27b. class requires a policy that
provides a ‘content_manager’ attribute for content management methods
like ‘set_content()’ and ‘get_content()’ to work.  The legacy *note
compat32: cbe. policy does not support these methods and should not be
used with ‘EmailMessage’.

   (7) https://datatracker.ietf.org/doc/html/rfc6531.html

   (8) https://datatracker.ietf.org/doc/html/rfc2231.html

   (9) https://datatracker.ietf.org/doc/html/rfc2231.html

   (10) https://datatracker.ietf.org/doc/html/rfc2045.html

   (11) https://datatracker.ietf.org/doc/html/rfc2045.html

   (12) https://datatracker.ietf.org/doc/html/rfc2045.html

   (13) https://datatracker.ietf.org/doc/html/rfc2231.html

   (14) https://datatracker.ietf.org/doc/html/rfc2183.html


File: python.info,  Node: email parser Parsing email messages,  Next: email generator Generating MIME documents,  Prev: email message Representing an email message,  Up: email — An email and MIME handling package

5.20.1.2 ‘email.parser’: Parsing email messages
...............................................

'Source code:' Lib/email/parser.py(1)

__________________________________________________________________

Message object structures can be created in one of two ways: they can be
created from whole cloth by creating an *note EmailMessage: 27b. object,
adding headers using the dictionary interface, and adding payload(s)
using *note set_content(): 1a03. and related methods, or they can be
created by parsing a serialized representation of the email message.

The *note email: 3b. package provides a standard parser that understands
most email document structures, including MIME documents.  You can pass
the parser a bytes, string or file object, and the parser will return to
you the root *note EmailMessage: 27b. instance of the object structure.
For simple, non-MIME messages the payload of this root object will
likely be a string containing the text of the message.  For MIME
messages, the root object will return ‘True’ from its *note
is_multipart(): 378d. method, and the subparts can be accessed via the
payload manipulation methods, such as *note get_body(): 37b1, *note
iter_parts(): 37b3, and *note walk(): 37b0.

There are actually two parser interfaces available for use, the *note
Parser: 11e1. API and the incremental *note FeedParser: 15d0. API. The
‘Parser’ API is most useful if you have the entire text of the message
in memory, or if the entire message lives in a file on the file system.
‘FeedParser’ is more appropriate when you are reading the message from a
stream which might block waiting for more input (such as reading an
email message from a socket).  The ‘FeedParser’ can consume and parse
the message incrementally, and only returns the root object when you
close the parser.

Note that the parser can be extended in limited ways, and of course you
can implement your own parser completely from scratch.  All of the logic
that connects the *note email: 3b. package’s bundled parser and the
*note EmailMessage: 27b. class is embodied in the *note Policy: 10f7.
class, so a custom parser can create message object trees any way it
finds necessary by implementing custom versions of the appropriate
‘Policy’ methods.

* Menu:

* FeedParser API::
* Parser API::
* Additional notes::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/parser.py


File: python.info,  Node: FeedParser API,  Next: Parser API,  Up: email parser Parsing email messages

5.20.1.3 FeedParser API
.......................

The *note BytesFeedParser: 1210, imported from the ‘email.feedparser’
module, provides an API that is conducive to incremental parsing of
email messages, such as would be necessary when reading the text of an
email message from a source that can block (such as a socket).  The
‘BytesFeedParser’ can of course be used to parse an email message fully
contained in a *note bytes-like object: d55, string, or file, but the
*note BytesParser: 1211. API may be more convenient for such use cases.
The semantics and results of the two parser APIs are identical.

The *note BytesFeedParser: 1210.’s API is simple; you create an
instance, feed it a bunch of bytes until there’s no more to feed it,
then close the parser to retrieve the root message object.  The
‘BytesFeedParser’ is extremely accurate when parsing standards-compliant
messages, and it does a very good job of parsing non-compliant messages,
providing information about how a message was deemed broken.  It will
populate a message object’s *note defects: 37c2. attribute with a list
of any problems it found in a message.  See the *note email.errors: 3f.
module for the list of defects that it can find.

Here is the API for the *note BytesFeedParser: 1210.:

 -- Class: email.parser.BytesFeedParser (_factory=None, *,
          policy=policy.compat32)

     Create a ‘BytesFeedParser’ instance.  Optional '_factory' is a
     no-argument callable; if not specified use the *note
     message_factory: cbd. from the 'policy'.  Call '_factory' whenever
     a new message object is needed.

     If 'policy' is specified use the rules it specifies to update the
     representation of the message.  If 'policy' is not set, use the
     *note compat32: 10f8. policy, which maintains backward
     compatibility with the Python 3.2 version of the email package and
     provides *note Message: 27c. as the default factory.  All other
     policies provide *note EmailMessage: 27b. as the default
     '_factory'.  For more information on what else 'policy' controls,
     see the *note policy: 4f. documentation.

     Note: 'The policy keyword should always be specified'; The default
     will change to *note email.policy.default: 15d1. in a future
     version of Python.

     Added in version 3.2.

     Changed in version 3.3: Added the 'policy' keyword.

     Changed in version 3.6: '_factory' defaults to the policy
     ‘message_factory’.

      -- Method: feed (data)

          Feed the parser some more data.  'data' should be a *note
          bytes-like object: d55. containing one or more lines.  The
          lines can be partial and the parser will stitch such partial
          lines together properly.  The lines can have any of the three
          common line endings: carriage return, newline, or carriage
          return and newline (they can even be mixed).

      -- Method: close ()

          Complete the parsing of all previously fed data and return the
          root message object.  It is undefined what happens if *note
          feed(): 37c7. is called after this method has been called.

 -- Class: email.parser.FeedParser (_factory=None, *,
          policy=policy.compat32)

     Works like *note BytesFeedParser: 1210. except that the input to
     the *note feed(): 37c7. method must be a string.  This is of
     limited utility, since the only way for such a message to be valid
     is for it to contain only ASCII text or, if *note utf8: e2a. is
     ‘True’, no binary attachments.

     Changed in version 3.3: Added the 'policy' keyword.


File: python.info,  Node: Parser API,  Next: Additional notes,  Prev: FeedParser API,  Up: email parser Parsing email messages

5.20.1.4 Parser API
...................

The *note BytesParser: 1211. class, imported from the ‘email.parser’
module, provides an API that can be used to parse a message when the
complete contents of the message are available in a *note bytes-like
object: d55. or file.  The ‘email.parser’ module also provides *note
Parser: 11e1. for parsing strings, and header-only parsers, *note
BytesHeaderParser: 10ff. and *note HeaderParser: 1100, which can be used
if you’re only interested in the headers of the message.
‘BytesHeaderParser’ and ‘HeaderParser’ can be much faster in these
situations, since they do not attempt to parse the message body, instead
setting the payload to the raw body.

 -- Class: email.parser.BytesParser (_class=None, *,
          policy=policy.compat32)

     Create a ‘BytesParser’ instance.  The '_class' and 'policy'
     arguments have the same meaning and semantics as the '_factory' and
     'policy' arguments of *note BytesFeedParser: 1210.

     Note: 'The policy keyword should always be specified'; The default
     will change to *note email.policy.default: 15d1. in a future
     version of Python.

     Changed in version 3.3: Removed the 'strict' argument that was
     deprecated in 2.4.  Added the 'policy' keyword.

     Changed in version 3.6: '_class' defaults to the policy
     ‘message_factory’.

      -- Method: parse (fp, headersonly=False)

          Read all the data from the binary file-like object 'fp', parse
          the resulting bytes, and return the message object.  'fp' must
          support both the *note readline(): 1373. and the *note read():
          1372. methods.

          The bytes contained in 'fp' must be formatted as a block of
          RFC 5322(1) (or, if *note utf8: e2a. is ‘True’, RFC 6532(2))
          style headers and header continuation lines, optionally
          preceded by an envelope header.  The header block is
          terminated either by the end of the data or by a blank line.
          Following the header block is the body of the message (which
          may contain MIME-encoded subparts, including subparts with a
          ‘Content-Transfer-Encoding’ of ‘8bit’).

          Optional 'headersonly' is a flag specifying whether to stop
          parsing after reading the headers or not.  The default is
          ‘False’, meaning it parses the entire contents of the file.

      -- Method: parsebytes (bytes, headersonly=False)

          Similar to the *note parse(): 37ca. method, except it takes a
          *note bytes-like object: d55. instead of a file-like object.
          Calling this method on a bytes-like object is equivalent to
          wrapping 'bytes' in a *note BytesIO: ed8. instance first and
          calling ‘parse()’.

          Optional 'headersonly' is as with the *note parse(): 37ca.
          method.

     Added in version 3.2.

 -- Class: email.parser.BytesHeaderParser (_class=None, *,
          policy=policy.compat32)

     Exactly like *note BytesParser: 1211, except that 'headersonly'
     defaults to ‘True’.

     Added in version 3.3.

 -- Class: email.parser.Parser (_class=None, *, policy=policy.compat32)

     This class is parallel to *note BytesParser: 1211, but handles
     string input.

     Changed in version 3.3: Removed the 'strict' argument.  Added the
     'policy' keyword.

     Changed in version 3.6: '_class' defaults to the policy
     ‘message_factory’.

      -- Method: parse (fp, headersonly=False)

          Read all the data from the text-mode file-like object 'fp',
          parse the resulting text, and return the root message object.
          'fp' must support both the *note readline(): 1e5e. and the
          *note read(): 1e24. methods on file-like objects.

          Other than the text mode requirement, this method operates
          like *note BytesParser.parse(): 37ca.

      -- Method: parsestr (text, headersonly=False)

          Similar to the *note parse(): 37cc. method, except it takes a
          string object instead of a file-like object.  Calling this
          method on a string is equivalent to wrapping 'text' in a *note
          StringIO: f5e. instance first and calling ‘parse()’.

          Optional 'headersonly' is as with the *note parse(): 37cc.
          method.

 -- Class: email.parser.HeaderParser (_class=None, *,
          policy=policy.compat32)

     Exactly like *note Parser: 11e1, except that 'headersonly' defaults
     to ‘True’.

Since creating a message object structure from a string or a file object
is such a common task, four functions are provided as a convenience.
They are available in the top-level *note email: 3b. package namespace.

 -- Function: email.message_from_bytes (s, _class=None, *,
          policy=policy.compat32)

     Return a message object structure from a *note bytes-like object:
     d55.  This is equivalent to ‘BytesParser().parsebytes(s)’.
     Optional '_class' and 'policy' are interpreted as with the *note
     BytesParser: 1211. class constructor.

     Added in version 3.2.

     Changed in version 3.3: Removed the 'strict' argument.  Added the
     'policy' keyword.

 -- Function: email.message_from_binary_file (fp, _class=None, *,
          policy=policy.compat32)

     Return a message object structure tree from an open binary *note
     file object: 1208.  This is equivalent to
     ‘BytesParser().parse(fp)’.  '_class' and 'policy' are interpreted
     as with the *note BytesParser: 1211. class constructor.

     Added in version 3.2.

     Changed in version 3.3: Removed the 'strict' argument.  Added the
     'policy' keyword.

 -- Function: email.message_from_string (s, _class=None, *,
          policy=policy.compat32)

     Return a message object structure from a string.  This is
     equivalent to ‘Parser().parsestr(s)’.  '_class' and 'policy' are
     interpreted as with the *note Parser: 11e1. class constructor.

     Changed in version 3.3: Removed the 'strict' argument.  Added the
     'policy' keyword.

 -- Function: email.message_from_file (fp, _class=None, *,
          policy=policy.compat32)

     Return a message object structure tree from an open *note file
     object: 1208.  This is equivalent to ‘Parser().parse(fp)’.
     '_class' and 'policy' are interpreted as with the *note Parser:
     11e1. class constructor.

     Changed in version 3.3: Removed the 'strict' argument.  Added the
     'policy' keyword.

     Changed in version 3.6: '_class' defaults to the policy
     ‘message_factory’.

Here’s an example of how you might use *note message_from_bytes(): 120e.
at an interactive Python prompt:

     >>> import email
     >>> msg = email.message_from_bytes(myBytes)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5322.html

   (2) https://datatracker.ietf.org/doc/html/rfc6532.html


File: python.info,  Node: Additional notes,  Prev: Parser API,  Up: email parser Parsing email messages

5.20.1.5 Additional notes
.........................

Here are some notes on the parsing semantics:

   * Most non-‘multipart’ type messages are parsed as a single message
     object with a string payload.  These objects will return ‘False’
     for *note is_multipart(): 378d, and *note iter_parts(): 37b3. will
     yield an empty list.

   * All ‘multipart’ type messages will be parsed as a container message
     object with a list of sub-message objects for their payload.  The
     outer container message will return ‘True’ for *note
     is_multipart(): 378d, and *note iter_parts(): 37b3. will yield a
     list of subparts.

   * Most messages with a content type of ‘message/*’ (such as
     ‘message/delivery-status’ and ‘message/rfc822’) will also be parsed
     as container object containing a list payload of length 1.  Their
     *note is_multipart(): 378d. method will return ‘True’.  The single
     element yielded by *note iter_parts(): 37b3. will be a sub-message
     object.

   * Some non-standards-compliant messages may not be internally
     consistent about their ‘multipart’-edness.  Such messages may have
     a ‘Content-Type’ header of type ‘multipart’, but their *note
     is_multipart(): 378d. method may return ‘False’.  If such messages
     were parsed with the *note FeedParser: 15d0, they will have an
     instance of the *note MultipartInvariantViolationDefect: 37d1.
     class in their 'defects' attribute list.  See *note email.errors:
     3f. for details.


File: python.info,  Node: email generator Generating MIME documents,  Next: email policy Policy Objects,  Prev: email parser Parsing email messages,  Up: email — An email and MIME handling package

5.20.1.6 ‘email.generator’: Generating MIME documents
.....................................................

'Source code:' Lib/email/generator.py(1)

__________________________________________________________________

One of the most common tasks is to generate the flat (serialized)
version of the email message represented by a message object structure.
You will need to do this if you want to send your message via *note
smtplib.SMTP.sendmail(): e8d, or print the message on the console.
Taking a message object structure and producing a serialized
representation is the job of the generator classes.

As with the *note email.parser: 4e. module, you aren’t limited to the
functionality of the bundled generator; you could write one from scratch
yourself.  However the bundled generator knows how to generate most
email in a standards-compliant way, should handle MIME and non-MIME
email messages just fine, and is designed so that the bytes-oriented
parsing and generation operations are inverses, assuming the same
non-transforming *note policy: 4f. is used for both.  That is, parsing
the serialized byte stream via the *note BytesParser: 1211. class and
then regenerating the serialized byte stream using *note BytesGenerator:
1214. should produce output identical to the input (2).  (On the other
hand, using the generator on an *note EmailMessage: 27b. constructed by
program may result in changes to the ‘EmailMessage’ object as defaults
are filled in.)

The *note Generator: 1213. class can be used to flatten a message into a
text (as opposed to binary) serialized representation, but since Unicode
cannot represent binary data directly, the message is of necessity
transformed into something that contains only ASCII characters, using
the standard email RFC Content Transfer Encoding techniques for encoding
email messages for transport over channels that are not “8 bit clean”.

To accommodate reproducible processing of SMIME-signed messages *note
Generator: 1213. disables header folding for message parts of type
‘multipart/signed’ and all subparts.

 -- Class: email.generator.BytesGenerator (outfp, mangle_from_=None,
          maxheaderlen=None, *, policy=None)

     Return a ‘BytesGenerator’ object that will write any message
     provided to the *note flatten(): 37d6. method, or any
     surrogateescape encoded text provided to the *note write(): 37d7.
     method, to the *note file-like object: 15f4. 'outfp'.  'outfp' must
     support a ‘write’ method that accepts binary data.

     If optional 'mangle_from_' is ‘True’, put a ‘>’ character in front
     of any line in the body that starts with the exact string ‘"From
     "’, that is ‘From’ followed by a space at the beginning of a line.
     'mangle_from_' defaults to the value of the *note mangle_from_:
     e28. setting of the 'policy' (which is ‘True’ for the *note
     compat32: cbe. policy and ‘False’ for all others).  'mangle_from_'
     is intended for use when messages are stored in Unix mbox format
     (see *note mailbox: 8b. and WHY THE CONTENT-LENGTH FORMAT IS
     BAD(3)).

     If 'maxheaderlen' is not ‘None’, refold any header lines that are
     longer than 'maxheaderlen', or if ‘0’, do not rewrap any headers.
     If 'manheaderlen' is ‘None’ (the default), wrap headers and other
     message lines according to the 'policy' settings.

     If 'policy' is specified, use that policy to control message
     generation.  If 'policy' is ‘None’ (the default), use the policy
     associated with the *note Message: 27c. or *note EmailMessage: 27b.
     object passed to ‘flatten’ to control the message generation.  See
     *note email.policy: 4f. for details on what 'policy' controls.

     Added in version 3.2.

     Changed in version 3.3: Added the 'policy' keyword.

     Changed in version 3.6: The default behavior of the 'mangle_from_'
     and 'maxheaderlen' parameters is to follow the policy.

      -- Method: flatten (msg, unixfrom=False, linesep=None)

          Print the textual representation of the message object
          structure rooted at 'msg' to the output file specified when
          the ‘BytesGenerator’ instance was created.

          If the *note policy: 4f. option *note cte_type: 37d8. is
          ‘8bit’ (the default), copy any headers in the original parsed
          message that have not been modified to the output with any
          bytes with the high bit set reproduced as in the original, and
          preserve the non-ASCII ‘Content-Transfer-Encoding’ of any body
          parts that have them.  If ‘cte_type’ is ‘7bit’, convert the
          bytes with the high bit set as needed using an
          ASCII-compatible ‘Content-Transfer-Encoding’.  That is,
          transform parts with non-ASCII ‘Content-Transfer-Encoding’
          (‘Content-Transfer-Encoding: 8bit’) to an ASCII compatible
          ‘Content-Transfer-Encoding’, and encode RFC-invalid non-ASCII
          bytes in headers using the MIME ‘unknown-8bit’ character set,
          thus rendering them RFC-compliant.

          If 'unixfrom' is ‘True’, print the envelope header delimiter
          used by the Unix mailbox format (see *note mailbox: 8b.)
          before the first of the RFC 5322(4) headers of the root
          message object.  If the root object has no envelope header,
          craft a standard one.  The default is ‘False’.  Note that for
          subparts, no envelope header is ever printed.

          If 'linesep' is not ‘None’, use it as the separator character
          between all the lines of the flattened message.  If 'linesep'
          is ‘None’ (the default), use the value specified in the
          'policy'.

      -- Method: clone (fp)

          Return an independent clone of this ‘BytesGenerator’ instance
          with the exact same option settings, and 'fp' as the new
          'outfp'.

      -- Method: write (s)

          Encode 's' using the ‘ASCII’ codec and the ‘surrogateescape’
          error handler, and pass it to the 'write' method of the
          'outfp' passed to the ‘BytesGenerator’’s constructor.

As a convenience, *note EmailMessage: 27b. provides the methods *note
as_bytes(): 378b. and ‘bytes(aMessage)’ (a.k.a.  *note __bytes__():
378c.), which simplify the generation of a serialized binary
representation of a message object.  For more detail, see *note
email.message: 44.

Because strings cannot represent binary data, the *note Generator: 1213.
class must convert any binary data in any message it flattens to an
ASCII compatible format, by converting them to an ASCII compatible
‘Content-Transfer_Encoding’.  Using the terminology of the email RFCs,
you can think of this as ‘Generator’ serializing to an I/O stream that
is not “8 bit clean”.  In other words, most applications will want to be
using *note BytesGenerator: 1214, and not ‘Generator’.

 -- Class: email.generator.Generator (outfp, mangle_from_=None,
          maxheaderlen=None, *, policy=None)

     Return a ‘Generator’ object that will write any message provided to
     the *note flatten(): 37da. method, or any text provided to the
     *note write(): 37db. method, to the *note file-like object: 15f4.
     'outfp'.  'outfp' must support a ‘write’ method that accepts string
     data.

     If optional 'mangle_from_' is ‘True’, put a ‘>’ character in front
     of any line in the body that starts with the exact string ‘"From
     "’, that is ‘From’ followed by a space at the beginning of a line.
     'mangle_from_' defaults to the value of the *note mangle_from_:
     e28. setting of the 'policy' (which is ‘True’ for the *note
     compat32: cbe. policy and ‘False’ for all others).  'mangle_from_'
     is intended for use when messages are stored in Unix mbox format
     (see *note mailbox: 8b. and WHY THE CONTENT-LENGTH FORMAT IS
     BAD(5)).

     If 'maxheaderlen' is not ‘None’, refold any header lines that are
     longer than 'maxheaderlen', or if ‘0’, do not rewrap any headers.
     If 'manheaderlen' is ‘None’ (the default), wrap headers and other
     message lines according to the 'policy' settings.

     If 'policy' is specified, use that policy to control message
     generation.  If 'policy' is ‘None’ (the default), use the policy
     associated with the *note Message: 27c. or *note EmailMessage: 27b.
     object passed to ‘flatten’ to control the message generation.  See
     *note email.policy: 4f. for details on what 'policy' controls.

     Changed in version 3.3: Added the 'policy' keyword.

     Changed in version 3.6: The default behavior of the 'mangle_from_'
     and 'maxheaderlen' parameters is to follow the policy.

      -- Method: flatten (msg, unixfrom=False, linesep=None)

          Print the textual representation of the message object
          structure rooted at 'msg' to the output file specified when
          the ‘Generator’ instance was created.

          If the *note policy: 4f. option *note cte_type: 37d8. is
          ‘8bit’, generate the message as if the option were set to
          ‘7bit’.  (This is required because strings cannot represent
          non-ASCII bytes.)  Convert any bytes with the high bit set as
          needed using an ASCII-compatible ‘Content-Transfer-Encoding’.
          That is, transform parts with non-ASCII
          ‘Content-Transfer-Encoding’ (‘Content-Transfer-Encoding:
          8bit’) to an ASCII compatible ‘Content-Transfer-Encoding’, and
          encode RFC-invalid non-ASCII bytes in headers using the MIME
          ‘unknown-8bit’ character set, thus rendering them
          RFC-compliant.

          If 'unixfrom' is ‘True’, print the envelope header delimiter
          used by the Unix mailbox format (see *note mailbox: 8b.)
          before the first of the RFC 5322(6) headers of the root
          message object.  If the root object has no envelope header,
          craft a standard one.  The default is ‘False’.  Note that for
          subparts, no envelope header is ever printed.

          If 'linesep' is not ‘None’, use it as the separator character
          between all the lines of the flattened message.  If 'linesep'
          is ‘None’ (the default), use the value specified in the
          'policy'.

          Changed in version 3.2: Added support for re-encoding ‘8bit’
          message bodies, and the 'linesep' argument.

      -- Method: clone (fp)

          Return an independent clone of this ‘Generator’ instance with
          the exact same options, and 'fp' as the new 'outfp'.

      -- Method: write (s)

          Write 's' to the 'write' method of the 'outfp' passed to the
          ‘Generator’’s constructor.  This provides just enough
          file-like API for ‘Generator’ instances to be used in the
          *note print(): fae. function.

As a convenience, *note EmailMessage: 27b. provides the methods *note
as_string(): 3788. and ‘str(aMessage)’ (a.k.a.  *note __str__(): 378a.),
which simplify the generation of a formatted string representation of a
message object.  For more detail, see *note email.message: 44.

The ‘email.generator’ module also provides a derived class, *note
DecodedGenerator: cbc, which is like the *note Generator: 1213. base
class, except that non-‘text’ parts are not serialized, but are instead
represented in the output stream by a string derived from a template
filled in with information about the part.

 -- Class: email.generator.DecodedGenerator (outfp, mangle_from_=None,
          maxheaderlen=None, fmt=None, *, policy=None)

     Act like *note Generator: 1213, except that for any subpart of the
     message passed to *note Generator.flatten(): 37da, if the subpart
     is of main type ‘text’, print the decoded payload of the subpart,
     and if the main type is not ‘text’, instead of printing it fill in
     the string 'fmt' using information from the part and print the
     resulting filled-in string.

     To fill in 'fmt', execute ‘fmt % part_info’, where ‘part_info’ is a
     dictionary composed of the following keys and values:

        * ‘type’ – Full MIME type of the non-‘text’ part

        * ‘maintype’ – Main MIME type of the non-‘text’ part

        * ‘subtype’ – Sub-MIME type of the non-‘text’ part

        * ‘filename’ – Filename of the non-‘text’ part

        * ‘description’ – Description associated with the non-‘text’
          part

        * ‘encoding’ – Content transfer encoding of the non-‘text’ part

     If 'fmt' is ‘None’, use the following default 'fmt':

          “[Non-text (%(type)s) part of message omitted, filename
          %(filename)s]”

     Optional '_mangle_from_' and 'maxheaderlen' are as with the *note
     Generator: 1213. base class.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/email/generator.py

   (2) This statement assumes that you use the appropriate setting for
‘unixfrom’, and that there are no *note email.policy: 4f. settings
calling for automatic adjustments (for example, *note refold_source:
37d5. must be ‘none’, which is 'not' the default).  It is also not 100%
true, since if the message does not conform to the RFC standards
occasionally information about the exact original text is lost during
parsing error recovery.  It is a goal to fix these latter edge cases
when possible.

   (3) https://www.jwz.org/doc/content-length.html

   (4) https://datatracker.ietf.org/doc/html/rfc5322.html

   (5) https://www.jwz.org/doc/content-length.html

   (6) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: email policy Policy Objects,  Next: email errors Exception and Defect classes,  Prev: email generator Generating MIME documents,  Up: email — An email and MIME handling package

5.20.1.7 ‘email.policy’: Policy Objects
.......................................

Added in version 3.3.

'Source code:' Lib/email/policy.py(1)

__________________________________________________________________

The *note email: 3b. package’s prime focus is the handling of email
messages as described by the various email and MIME RFCs.  However, the
general format of email messages (a block of header fields each
consisting of a name followed by a colon followed by a value, the whole
block followed by a blank line and an arbitrary ‘body’), is a format
that has found utility outside of the realm of email.  Some of these
uses conform fairly closely to the main email RFCs, some do not.  Even
when working with email, there are times when it is desirable to break
strict compliance with the RFCs, such as generating emails that
interoperate with email servers that do not themselves follow the
standards, or that implement extensions you want to use in ways that
violate the standards.

Policy objects give the email package the flexibility to handle all
these disparate use cases.

A *note Policy: 10f7. object encapsulates a set of attributes and
methods that control the behavior of various components of the email
package during use.  ‘Policy’ instances can be passed to various classes
and methods in the email package to alter the default behavior.  The
settable values and their defaults are described below.

There is a default policy used by all classes in the email package.  For
all of the *note parser: 4e. classes and the related convenience
functions, and for the *note Message: 27c. class, this is the *note
Compat32: 10f8. policy, via its corresponding pre-defined instance *note
compat32: cbe.  This policy provides for complete backward compatibility
(in some cases, including bug compatibility) with the pre-Python3.3
version of the email package.

This default value for the 'policy' keyword to *note EmailMessage: 27b.
is the *note EmailPolicy: 10fb. policy, via its pre-defined instance
*note default: 15d1.

When a *note Message: 27c. or *note EmailMessage: 27b. object is
created, it acquires a policy.  If the message is created by a *note
parser: 4e, a policy passed to the parser will be the policy used by the
message it creates.  If the message is created by the program, then the
policy can be specified when it is created.  When a message is passed to
a *note generator: 40, the generator uses the policy from the message by
default, but you can also pass a specific policy to the generator that
will override the one stored on the message object.

The default value for the 'policy' keyword for the *note email.parser:
4e. classes and the parser convenience functions 'will be changing' in a
future version of Python.  Therefore you should 'always specify
explicitly which policy you want to use' when calling any of the classes
and functions described in the ‘parser’ module.

The first part of this documentation covers the features of *note
Policy: 10f7, an *note abstract base class: 11fa. that defines the
features that are common to all policy objects, including *note
compat32: cbe.  This includes certain hook methods that are called
internally by the email package, which a custom policy could override to
obtain different behavior.  The second part describes the concrete
classes *note EmailPolicy: 10fb. and *note Compat32: 10f8, which
implement the hooks that provide the standard behavior and the backward
compatible behavior and features, respectively.

*note Policy: 10f7. instances are immutable, but they can be cloned,
accepting the same keyword arguments as the class constructor and
returning a new ‘Policy’ instance that is a copy of the original but
with the specified attributes values changed.

As an example, the following code could be used to read an email message
from a file on disk and pass it to the system ‘sendmail’ program on a
Unix system:

     >>> from email import message_from_binary_file
     >>> from email.generator import BytesGenerator
     >>> from email import policy
     >>> from subprocess import Popen, PIPE
     >>> with open('mymsg.txt', 'rb') as f:
     ...     msg = message_from_binary_file(f, policy=policy.default)
     ...
     >>> p = Popen(['sendmail', msg['To'].addresses[0]], stdin=PIPE)
     >>> g = BytesGenerator(p.stdin, policy=msg.policy.clone(linesep='\r\n'))
     >>> g.flatten(msg)
     >>> p.stdin.close()
     >>> rc = p.wait()

Here we are telling *note BytesGenerator: 1214. to use the RFC correct
line separator characters when creating the binary string to feed into
‘sendmail's’ ‘stdin’, where the default policy would use ‘\n’ line
separators.

Some email package methods accept a 'policy' keyword argument, allowing
the policy to be overridden for that method.  For example, the following
code uses the *note as_bytes(): f6f. method of the 'msg' object from the
previous example and writes the message to a file using the native line
separators for the platform on which it is running:

     >>> import os
     >>> with open('converted.txt', 'wb') as f:
     ...     f.write(msg.as_bytes(policy=msg.policy.clone(linesep=os.linesep)))
     17

Policy objects can also be combined using the addition operator,
producing a policy object whose settings are a combination of the
non-default values of the summed objects:

     >>> compat_SMTP = policy.compat32.clone(linesep='\r\n')
     >>> compat_strict = policy.compat32.clone(raise_on_defect=True)
     >>> compat_strict_SMTP = compat_SMTP + compat_strict

This operation is not commutative; that is, the order in which the
objects are added matters.  To illustrate:

     >>> policy100 = policy.compat32.clone(max_line_length=100)
     >>> policy80 = policy.compat32.clone(max_line_length=80)
     >>> apolicy = policy100 + policy80
     >>> apolicy.max_line_length
     80
     >>> apolicy = policy80 + policy100
     >>> apolicy.max_line_length
     100

 -- Class: email.policy.Policy (**kw)

     This is the *note abstract base class: 11fa. for all policy
     classes.  It provides default implementations for a couple of
     trivial methods, as well as the implementation of the immutability
     property, the *note clone(): 10f9. method, and the constructor
     semantics.

     The constructor of a policy class can be passed various keyword
     arguments.  The arguments that may be specified are any non-method
     properties on this class, plus any additional non-method properties
     on the concrete class.  A value specified in the constructor will
     override the default value for the corresponding attribute.

     This class defines the following properties, and thus values for
     the following may be passed in the constructor of any policy class:

      -- Attribute: max_line_length

          The maximum length of any line in the serialized output, not
          counting the end of line character(s).  Default is 78, per RFC
          5322(2).  A value of ‘0’ or *note None: 678. indicates that no
          line wrapping should be done at all.

      -- Attribute: linesep

          The string to be used to terminate lines in serialized output.
          The default is ‘\n’ because that’s the internal end-of-line
          discipline used by Python, though ‘\r\n’ is required by the
          RFCs.

      -- Attribute: cte_type

          Controls the type of Content Transfer Encodings that may be or
          are required to be used.  The possible values are:

          ‘7bit’       all data must be “7 bit clean” (ASCII-only).  This means that
                       where necessary data will be encoded using either
                       quoted-printable or base64 encoding.
                       
                       
          ‘8bit’       data is not constrained to be 7 bit clean.  Data in headers is
                       still required to be ASCII-only and so will be encoded (see
                       *note fold_binary(): 37e1. and *note utf8: e2a. below for
                       exceptions), but body parts may use the ‘8bit’ CTE.
                       

          A ‘cte_type’ value of ‘8bit’ only works with ‘BytesGenerator’,
          not ‘Generator’, because strings cannot contain binary data.
          If a ‘Generator’ is operating under a policy that specifies
          ‘cte_type=8bit’, it will act as if ‘cte_type’ is ‘7bit’.

      -- Attribute: raise_on_defect

          If *note True: c2d, any defects encountered will be raised as
          errors.  If *note False: b4f. (the default), defects will be
          passed to the *note register_defect(): 37e3. method.

      -- Attribute: mangle_from_

          If *note True: c2d, lines starting with '“From “' in the body
          are escaped by putting a ‘>’ in front of them.  This parameter
          is used when the message is being serialized by a generator.
          Default: *note False: b4f.

          Added in version 3.5.

      -- Attribute: message_factory

          A factory function for constructing a new empty message
          object.  Used by the parser when building messages.  Defaults
          to ‘None’, in which case *note Message: 27c. is used.

          Added in version 3.6.

      -- Attribute: verify_generated_headers

          If ‘True’ (the default), the generator will raise *note
          HeaderWriteError: 37e4. instead of writing a header that is
          improperly folded or delimited, such that it would be parsed
          as multiple headers or joined with adjacent data.  Such
          headers can be generated by custom header classes or bugs in
          the ‘email’ module.

          As it’s a security feature, this defaults to ‘True’ even in
          the *note Compat32: 10f8. policy.  For backwards compatible,
          but unsafe, behavior, it must be set to ‘False’ explicitly.

          Added in version 3.13.

     The following ‘Policy’ method is intended to be called by code
     using the email library to create policy instances with custom
     settings:

      -- Method: clone (**kw)

          Return a new ‘Policy’ instance whose attributes have the same
          values as the current instance, except where those attributes
          are given new values by the keyword arguments.

     The remaining ‘Policy’ methods are called by the email package
     code, and are not intended to be called by an application using the
     email package.  A custom policy must implement all of these
     methods.

      -- Method: handle_defect (obj, defect)

          Handle a 'defect' found on 'obj'.  When the email package
          calls this method, 'defect' will always be a subclass of *note
          MessageDefect: 37e6.

          The default implementation checks the *note raise_on_defect:
          37e2. flag.  If it is ‘True’, 'defect' is raised as an
          exception.  If it is ‘False’ (the default), 'obj' and 'defect'
          are passed to *note register_defect(): 37e3.

      -- Method: register_defect (obj, defect)

          Register a 'defect' on 'obj'.  In the email package, 'defect'
          will always be a subclass of *note MessageDefect: 37e6.

          The default implementation calls the ‘append’ method of the
          ‘defects’ attribute of 'obj'.  When the email package calls
          *note handle_defect: 37e5, 'obj' will normally have a
          ‘defects’ attribute that has an ‘append’ method.  Custom
          object types used with the email package (for example, custom
          ‘Message’ objects) should also provide such an attribute,
          otherwise defects in parsed messages will raise unexpected
          errors.

      -- Method: header_max_count (name)

          Return the maximum allowed number of headers named 'name'.

          Called when a header is added to an *note EmailMessage: 27b.
          or *note Message: 27c. object.  If the returned value is not
          ‘0’ or ‘None’, and there are already a number of headers with
          the name 'name' greater than or equal to the value returned, a
          *note ValueError: 202. is raised.

          Because the default behavior of ‘Message.__setitem__’ is to
          append the value to the list of headers, it is easy to create
          duplicate headers without realizing it.  This method allows
          certain headers to be limited in the number of instances of
          that header that may be added to a ‘Message’ programmatically.
          (The limit is not observed by the parser, which will
          faithfully produce as many headers as exist in the message
          being parsed.)

          The default implementation returns ‘None’ for all header
          names.

      -- Method: header_source_parse (sourcelines)

          The email package calls this method with a list of strings,
          each string ending with the line separation characters found
          in the source being parsed.  The first line includes the field
          header name and separator.  All whitespace in the source is
          preserved.  The method should return the ‘(name, value)’ tuple
          that is to be stored in the ‘Message’ to represent the parsed
          header.

          If an implementation wishes to retain compatibility with the
          existing email package policies, 'name' should be the case
          preserved name (all characters up to the ‘‘:’’ separator),
          while 'value' should be the unfolded value (all line separator
          characters removed, but whitespace kept intact), stripped of
          leading whitespace.

          'sourcelines' may contain surrogateescaped binary data.

          There is no default implementation

      -- Method: header_store_parse (name, value)

          The email package calls this method with the name and value
          provided by the application program when the application
          program is modifying a ‘Message’ programmatically (as opposed
          to a ‘Message’ created by a parser).  The method should return
          the ‘(name, value)’ tuple that is to be stored in the
          ‘Message’ to represent the header.

          If an implementation wishes to retain compatibility with the
          existing email package policies, the 'name' and 'value' should
          be strings or string subclasses that do not change the content
          of the passed in arguments.

          There is no default implementation

      -- Method: header_fetch_parse (name, value)

          The email package calls this method with the 'name' and
          'value' currently stored in the ‘Message’ when that header is
          requested by the application program, and whatever the method
          returns is what is passed back to the application as the value
          of the header being retrieved.  Note that there may be more
          than one header with the same name stored in the ‘Message’;
          the method is passed the specific name and value of the header
          destined to be returned to the application.

          'value' may contain surrogateescaped binary data.  There
          should be no surrogateescaped binary data in the value
          returned by the method.

          There is no default implementation

      -- Method: fold (name, value)

          The email package calls this method with the 'name' and
          'value' currently stored in the ‘Message’ for a given header.
          The method should return a string that represents that header
          “folded” correctly (according to the policy settings) by
          composing the 'name' with the 'value' and inserting *note
          linesep: 37e0. characters at the appropriate places.  See RFC
          5322(3) for a discussion of the rules for folding email
          headers.

          'value' may contain surrogateescaped binary data.  There
          should be no surrogateescaped binary data in the string
          returned by the method.

      -- Method: fold_binary (name, value)

          The same as *note fold(): 37eb, except that the returned value
          should be a bytes object rather than a string.

          'value' may contain surrogateescaped binary data.  These could
          be converted back into binary data in the returned bytes
          object.

 -- Class: email.policy.EmailPolicy (**kw)

     This concrete *note Policy: 10f7. provides behavior that is
     intended to be fully compliant with the current email RFCs.  These
     include (but are not limited to) RFC 5322(4), RFC 2047(5), and the
     current MIME RFCs.

     This policy adds new header parsing and folding algorithms.
     Instead of simple strings, headers are ‘str’ subclasses with
     attributes that depend on the type of the field.  The parsing and
     folding algorithm fully implement RFC 2047(6) and RFC 5322(7).

     The default value for the *note message_factory: cbd. attribute is
     *note EmailMessage: 27b.

     In addition to the settable attributes listed above that apply to
     all policies, this policy adds the following additional attributes:

     Added in version 3.6: (8)

      -- Attribute: utf8

          If ‘False’, follow RFC 5322(9), supporting non-ASCII
          characters in headers by encoding them as “encoded words”.  If
          ‘True’, follow RFC 6532(10) and use ‘utf-8’ encoding for
          headers.  Messages formatted in this way may be passed to SMTP
          servers that support the ‘SMTPUTF8’ extension ( RFC 6531(11)).

      -- Attribute: refold_source

          If the value for a header in the ‘Message’ object originated
          from a *note parser: 4e. (as opposed to being set by a
          program), this attribute indicates whether or not a generator
          should refold that value when transforming the message back
          into serialized form.  The possible values are:

          ‘none’       all source values use original folding
                       
                       
          ‘long’       source values that have any line that is longer than
                       ‘max_line_length’ will be refolded
                       
                       
          ‘all’        all values are refolded.
                       

          The default is ‘long’.

      -- Attribute: header_factory

          A callable that takes two arguments, ‘name’ and ‘value’, where
          ‘name’ is a header field name and ‘value’ is an unfolded
          header field value, and returns a string subclass that
          represents that header.  A default ‘header_factory’ (see *note
          headerregistry: 42.) is provided that supports custom parsing
          for the various address and date RFC 5322(12) header field
          types, and the major MIME header field stypes.  Support for
          additional custom parsing will be added in the future.

      -- Attribute: content_manager

          An object with at least two methods: get_content and
          set_content.  When the *note get_content(): 37b4. or *note
          set_content(): 1a03. method of an *note EmailMessage: 27b.
          object is called, it calls the corresponding method of this
          object, passing it the message object as its first argument,
          and any arguments or keywords that were passed to it as
          additional arguments.  By default ‘content_manager’ is set to
          *note raw_data_manager: 37ed.

          Added in version 3.4.

     The class provides the following concrete implementations of the
     abstract methods of *note Policy: 10f7.:

      -- Method: header_max_count (name)

          Returns the value of the *note max_count: 37ef. attribute of
          the specialized class used to represent the header with the
          given name.

      -- Method: header_source_parse (sourcelines)

          The name is parsed as everything up to the ‘‘:’’ and returned
          unmodified.  The value is determined by stripping leading
          whitespace off the remainder of the first line, joining all
          subsequent lines together, and stripping any trailing carriage
          return or linefeed characters.

      -- Method: header_store_parse (name, value)

          The name is returned unchanged.  If the input value has a
          ‘name’ attribute and it matches 'name' ignoring case, the
          value is returned unchanged.  Otherwise the 'name' and 'value'
          are passed to ‘header_factory’, and the resulting header
          object is returned as the value.  In this case a ‘ValueError’
          is raised if the input value contains CR or LF characters.

      -- Method: header_fetch_parse (name, value)

          If the value has a ‘name’ attribute, it is returned to
          unmodified.  Otherwise the 'name', and the 'value' with any CR
          or LF characters removed, are passed to the ‘header_factory’,
          and the resulting header object is returned.  Any
          surrogateescaped bytes get turned into the unicode
          unknown-character glyph.

      -- Method: fold (name, value)

          Header folding is controlled by the *note refold_source: 37d5.
          policy setting.  A value is considered to be a ‘source value’
          if and only if it does not have a ‘name’ attribute (having a
          ‘name’ attribute means it is a header object of some sort).
          If a source value needs to be refolded according to the
          policy, it is converted into a header object by passing the
          'name' and the 'value' with any CR and LF characters removed
          to the ‘header_factory’.  Folding of a header object is done
          by calling its ‘fold’ method with the current policy.

          Source values are split into lines using *note splitlines():
          129d.  If the value is not to be refolded, the lines are
          rejoined using the ‘linesep’ from the policy and returned.
          The exception is lines containing non-ascii binary data.  In
          that case the value is refolded regardless of the
          ‘refold_source’ setting, which causes the binary data to be
          CTE encoded using the ‘unknown-8bit’ charset.

      -- Method: fold_binary (name, value)

          The same as *note fold(): 1788. if *note cte_type: 37d8. is
          ‘7bit’, except that the returned value is bytes.

          If *note cte_type: 37d8. is ‘8bit’, non-ASCII binary data is
          converted back into bytes.  Headers with binary data are not
          refolded, regardless of the ‘refold_header’ setting, since
          there is no way to know whether the binary data consists of
          single byte characters or multibyte characters.

The following instances of *note EmailPolicy: 10fb. provide defaults
suitable for specific application domains.  Note that in the future the
behavior of these instances (in particular the ‘HTTP’ instance) may be
adjusted to conform even more closely to the RFCs relevant to their
domains.

 -- Data: email.policy.default

     An instance of ‘EmailPolicy’ with all defaults unchanged.  This
     policy uses the standard Python ‘\n’ line endings rather than the
     RFC-correct ‘\r\n’.

 -- Data: email.policy.SMTP

     Suitable for serializing messages in conformance with the email
     RFCs.  Like ‘default’, but with ‘linesep’ set to ‘\r\n’, which is
     RFC compliant.

 -- Data: email.policy.SMTPUTF8

     The same as ‘SMTP’ except that *note utf8: e2a. is ‘True’.  Useful
     for serializing messages to a message store without using encoded
     words in the headers.  Should only be used for SMTP transmission if
     the sender or recipient addresses have non-ASCII characters (the
     *note smtplib.SMTP.send_message(): e8e. method handles this
     automatically).

 -- Data: email.policy.HTTP

     Suitable for serializing headers with for use in HTTP traffic.
     Like ‘SMTP’ except that ‘max_line_length’ is set to ‘None’
     (unlimited).

 -- Data: email.policy.strict

     Convenience instance.  The same as ‘default’ except that
     ‘raise_on_defect’ is set to ‘True’.  This allows any policy to be
     made strict by writing:

          somepolicy + policy.strict

With all of these *note EmailPolicies: 10fb, the effective API of the
email package is changed from the Python 3.2 API in the following ways:

   * Setting a header on a *note Message: 27c. results in that header
     being parsed and a header object created.

   * Fetching a header value from a *note Message: 27c. results in that
     header being parsed and a header object created and returned.

   * Any header object, or any header that is refolded due to the policy
     settings, is folded using an algorithm that fully implements the
     RFC folding algorithms, including knowing where encoded words are
     required and allowed.

From the application view, this means that any header obtained through
the *note EmailMessage: 27b. is a header object with extra attributes,
whose string value is the fully decoded unicode value of the header.
Likewise, a header may be assigned a new value, or a new header created,
using a unicode string, and the policy will take care of converting the
unicode string into the correct RFC encoded form.

The header objects and their attributes are described in *note
headerregistry: 42.

 -- Class: email.policy.Compat32 (**kw)

     This concrete *note Policy: 10f7. is the backward compatibility
     policy.  It replicates the behavior of the email package in Python
     3.2.  The ‘policy’ module also defines an instance of this class,
     *note compat32: cbe, that is used as the default policy.  Thus the
     default behavior of the email package is to maintain compatibility
     with Python 3.2.

     The following attributes have values that are different from the
     *note Policy: 10f7. default:

      -- Attribute: mangle_from_

          The default is ‘True’.

     The class provides the following concrete implementations of the
     abstract methods of *note Policy: 10f7.:

      -- Method: header_source_parse (sourcelines)

          The name is parsed as everything up to the ‘‘:’’ and returned
          unmodified.  The value is determined by stripping leading
          whitespace off the remainder of the first line, joining all
          subsequent lines together, and stripping any trailing carriage
          return or linefeed characters.

      -- Method: header_store_parse (name, value)

          The name and value are returned unmodified.

      -- Method: header_fetch_parse (name, value)

          If the value contains binary data, it is converted into a
          *note Header: 1a04. object using the ‘unknown-8bit’ charset.
          Otherwise it is returned unmodified.

      -- Method: fold (name, value)

          Headers are folded using the *note Header: 1a04. folding
          algorithm, which preserves existing line breaks in the value,
          and wraps each resulting line to the ‘max_line_length’.
          Non-ASCII binary data are CTE encoded using the ‘unknown-8bit’
          charset.

      -- Method: fold_binary (name, value)

          Headers are folded using the *note Header: 1a04. folding
          algorithm, which preserves existing line breaks in the value,
          and wraps each resulting line to the ‘max_line_length’.  If
          ‘cte_type’ is ‘7bit’, non-ascii binary data is CTE encoded
          using the ‘unknown-8bit’ charset.  Otherwise the original
          source header is used, with its existing line breaks and any
          (RFC invalid) binary data it may contain.

 -- Data: email.policy.compat32

     An instance of *note Compat32: 10f8, providing backward
     compatibility with the behavior of the email package in Python 3.2.

          Note: The *note compat32: cbe. policy should not be used as a
          policy for *note EmailMessage: 27b. objects, and should only
          be used to serialize messages that were created using the
          ‘compat32’ policy.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/policy.py

   (2) https://datatracker.ietf.org/doc/html/rfc5322.html

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html

   (4) https://datatracker.ietf.org/doc/html/rfc5322.html

   (5) https://datatracker.ietf.org/doc/html/rfc2047.html

   (6) https://datatracker.ietf.org/doc/html/rfc2047.html

   (7) https://datatracker.ietf.org/doc/html/rfc5322.html

   (8) Originally added in 3.3 as a *note provisional feature: 107f.

   (9) https://datatracker.ietf.org/doc/html/rfc5322.html

   (10) https://datatracker.ietf.org/doc/html/rfc6532.html

   (11) https://datatracker.ietf.org/doc/html/rfc6531.html

   (12) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: email errors Exception and Defect classes,  Next: email headerregistry Custom Header Objects,  Prev: email policy Policy Objects,  Up: email — An email and MIME handling package

5.20.1.8 ‘email.errors’: Exception and Defect classes
.....................................................

'Source code:' Lib/email/errors.py(1)

__________________________________________________________________

The following exception classes are defined in the ‘email.errors’
module:

 -- Exception: email.errors.MessageError

     This is the base class for all exceptions that the *note email: 3b.
     package can raise.  It is derived from the standard *note
     Exception: 9e5. class and defines no additional methods.

 -- Exception: email.errors.MessageParseError

     This is the base class for exceptions raised by the *note Parser:
     11e1. class.  It is derived from *note MessageError: 37ff.  This
     class is also used internally by the parser used by *note
     headerregistry: 42.

 -- Exception: email.errors.HeaderParseError

     Raised under some error conditions when parsing the RFC 5322(2)
     headers of a message, this class is derived from *note
     MessageParseError: 3800.  The *note set_boundary(): 37a9. method
     will raise this error if the content type is unknown when the
     method is called.  *note Header: 1a04. may raise this error for
     certain base64 decoding errors, and when an attempt is made to
     create a header that appears to contain an embedded header (that
     is, there is what is supposed to be a continuation line that has no
     leading whitespace and looks like a header).

 -- Exception: email.errors.BoundaryError

     Deprecated and no longer used.

 -- Exception: email.errors.MultipartConversionError

     Raised if the *note attach(): 37bb. method is called on an instance
     of a class derived from *note MIMENonMultipart: 3803. (e.g.  *note
     MIMEImage: 3804.).  ‘MultipartConversionError’ multiply inherits
     from *note MessageError: 37ff. and the built-in *note TypeError:
     2c3.

 -- Exception: email.errors.HeaderWriteError

     Raised when an error occurs when the *note generator: 40. outputs
     headers.

 -- Exception: email.errors.MessageDefect

     This is the base class for all defects found when parsing email
     messages.  It is derived from *note ValueError: 202.

 -- Exception: email.errors.HeaderDefect

     This is the base class for all defects found when parsing email
     headers.  It is derived from *note MessageDefect: 37e6.

Here is the list of the defects that the *note FeedParser: 15d0. can
find while parsing messages.  Note that the defects are added to the
message where the problem was found, so for example, if a message nested
inside a ‘multipart/alternative’ had a malformed header, that nested
message object would have a defect, but the containing messages would
not.

All defect classes are subclassed from *note email.errors.MessageDefect:
37e6.

 -- Exception: email.errors.NoBoundaryInMultipartDefect

     A message claimed to be a multipart, but had no ‘boundary’
     parameter.

 -- Exception: email.errors.StartBoundaryNotFoundDefect

     The start boundary claimed in the ‘Content-Type’ header was never
     found.

 -- Exception: email.errors.CloseBoundaryNotFoundDefect

     A start boundary was found, but no corresponding close boundary was
     ever found.

     Added in version 3.3.

 -- Exception: email.errors.FirstHeaderLineIsContinuationDefect

     The message had a continuation line as its first header line.

 -- Exception: email.errors.MisplacedEnvelopeHeaderDefect

     A “Unix From” header was found in the middle of a header block.

 -- Exception: email.errors.MissingHeaderBodySeparatorDefect

     A line was found while parsing headers that had no leading white
     space but contained no ‘:’.  Parsing continues assuming that the
     line represents the first line of the body.

     Added in version 3.3.

 -- Exception: email.errors.MalformedHeaderDefect

     A header was found that was missing a colon, or was otherwise
     malformed.

     Deprecated since version 3.3: This defect has not been used for
     several Python versions.

 -- Exception: email.errors.MultipartInvariantViolationDefect

     A message claimed to be a ‘multipart’, but no subparts were found.
     Note that when a message has this defect, its *note is_multipart():
     37ae. method may return ‘False’ even though its content type claims
     to be ‘multipart’.

 -- Exception: email.errors.InvalidBase64PaddingDefect

     When decoding a block of base64 encoded bytes, the padding was not
     correct.  Enough padding is added to perform the decode, but the
     resulting decoded bytes may be invalid.

 -- Exception: email.errors.InvalidBase64CharactersDefect

     When decoding a block of base64 encoded bytes, characters outside
     the base64 alphabet were encountered.  The characters are ignored,
     but the resulting decoded bytes may be invalid.

 -- Exception: email.errors.InvalidBase64LengthDefect

     When decoding a block of base64 encoded bytes, the number of
     non-padding base64 characters was invalid (1 more than a multiple
     of 4).  The encoded block was kept as-is.

 -- Exception: email.errors.InvalidDateDefect

     When decoding an invalid or unparsable date field.  The original
     value is kept as-is.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/errors.py

   (2) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: email headerregistry Custom Header Objects,  Next: email contentmanager Managing MIME Content,  Prev: email errors Exception and Defect classes,  Up: email — An email and MIME handling package

5.20.1.9 ‘email.headerregistry’: Custom Header Objects
......................................................

'Source code:' Lib/email/headerregistry.py(1)

__________________________________________________________________

Added in version 3.6: (2)

Headers are represented by customized subclasses of *note str: 44f.  The
particular class used to represent a given header is determined by the
*note header_factory: 37ec. of the *note policy: 4f. in effect when the
headers are created.  This section documents the particular
‘header_factory’ implemented by the email package for handling RFC
5322(3) compliant email messages, which not only provides customized
header objects for various header types, but also provides an extension
mechanism for applications to add their own custom header types.

When using any of the policy objects derived from *note EmailPolicy:
10fb, all headers are produced by *note HeaderRegistry: 3814. and have
*note BaseHeader: 3796. as their last base class.  Each header class has
an additional base class that is determined by the type of the header.
For example, many headers have the class *note UnstructuredHeader: 3815.
as their other base class.  The specialized second class for a header is
determined by the name of the header, using a lookup table stored in the
‘HeaderRegistry’.  All of this is managed transparently for the typical
application program, but interfaces are provided for modifying the
default behavior for use by more complex applications.

The sections below first document the header base classes and their
attributes, followed by the API for modifying the behavior of *note
HeaderRegistry: 3814, and finally the support classes used to represent
the data parsed from structured headers.

 -- Class: email.headerregistry.BaseHeader (name, value)

     'name' and 'value' are passed to ‘BaseHeader’ from the *note
     header_factory: 37ec. call.  The string value of any header object
     is the 'value' fully decoded to unicode.

     This base class defines the following read-only properties:

      -- Attribute: name

          The name of the header (the portion of the field before the
          ‘:’).  This is exactly the value passed in the *note
          header_factory: 37ec. call for 'name'; that is, case is
          preserved.

      -- Attribute: defects

          A tuple of *note HeaderDefect: 3805. instances reporting any
          RFC compliance problems found during parsing.  The email
          package tries to be complete about detecting compliance
          issues.  See the *note errors: 3f. module for a discussion of
          the types of defects that may be reported.

      -- Attribute: max_count

          The maximum number of headers of this type that can have the
          same ‘name’.  A value of ‘None’ means unlimited.  The
          ‘BaseHeader’ value for this attribute is ‘None’; it is
          expected that specialized header classes will override this
          value as needed.

     ‘BaseHeader’ also provides the following method, which is called by
     the email library code and should not in general be called by
     application programs:

      -- Method: fold (*, policy)

          Return a string containing *note linesep: 37e0. characters as
          required to correctly fold the header according to 'policy'.
          A *note cte_type: 37d8. of ‘8bit’ will be treated as if it
          were ‘7bit’, since headers may not contain arbitrary binary
          data.  If *note utf8: e2a. is ‘False’, non-ASCII data will be
          RFC 2047(4) encoded.

     ‘BaseHeader’ by itself cannot be used to create a header object.
     It defines a protocol that each specialized header cooperates with
     in order to produce the header object.  Specifically, ‘BaseHeader’
     requires that the specialized class provide a *note classmethod():
     166. named ‘parse’.  This method is called as follows:

          parse(string, kwds)

     ‘kwds’ is a dictionary containing one pre-initialized key,
     ‘defects’.  ‘defects’ is an empty list.  The parse method should
     append any detected defects to this list.  On return, the ‘kwds’
     dictionary 'must' contain values for at least the keys ‘decoded’
     and ‘defects’.  ‘decoded’ should be the string value for the header
     (that is, the header value fully decoded to unicode).  The parse
     method should assume that 'string' may contain
     content-transfer-encoded parts, but should correctly handle all
     valid unicode characters as well so that it can parse un-encoded
     header values.

     ‘BaseHeader’’s ‘__new__’ then creates the header instance, and
     calls its ‘init’ method.  The specialized class only needs to
     provide an ‘init’ method if it wishes to set additional attributes
     beyond those provided by ‘BaseHeader’ itself.  Such an ‘init’
     method should look like this:

          def init(self, /, *args, **kw):
              self._myattr = kw.pop('myattr')
              super().init(*args, **kw)

     That is, anything extra that the specialized class puts in to the
     ‘kwds’ dictionary should be removed and handled, and the remaining
     contents of ‘kw’ (and ‘args’) passed to the ‘BaseHeader’ ‘init’
     method.

 -- Class: email.headerregistry.UnstructuredHeader

     An “unstructured” header is the default type of header in RFC
     5322(5).  Any header that does not have a specified syntax is
     treated as unstructured.  The classic example of an unstructured
     header is the ‘Subject’ header.

     In RFC 5322(6), an unstructured header is a run of arbitrary text
     in the ASCII character set.  RFC 2047(7), however, has an RFC
     5322(8) compatible mechanism for encoding non-ASCII text as ASCII
     characters within a header value.  When a 'value' containing
     encoded words is passed to the constructor, the
     ‘UnstructuredHeader’ parser converts such encoded words into
     unicode, following the RFC 2047(9) rules for unstructured text.
     The parser uses heuristics to attempt to decode certain
     non-compliant encoded words.  Defects are registered in such cases,
     as well as defects for issues such as invalid characters within the
     encoded words or the non-encoded text.

     This header type provides no additional attributes.

 -- Class: email.headerregistry.DateHeader

     RFC 5322(10) specifies a very specific format for dates within
     email headers.  The ‘DateHeader’ parser recognizes that date
     format, as well as recognizing a number of variant forms that are
     sometimes found “in the wild”.

     This header type provides the following additional attributes:

      -- Attribute: datetime

          If the header value can be recognized as a valid date of one
          form or another, this attribute will contain a *note datetime:
          1cc. instance representing that date.  If the timezone of the
          input date is specified as ‘-0000’ (indicating it is in UTC
          but contains no information about the source timezone), then
          *note datetime: 381a. will be a naive ‘datetime’.  If a
          specific timezone offset is found (including ‘+0000’), then
          ‘datetime’ will contain an aware ‘datetime’ that uses *note
          datetime.timezone: 1103. to record the timezone offset.

     The ‘decoded’ value of the header is determined by formatting the
     ‘datetime’ according to the RFC 5322(11) rules; that is, it is set
     to:

          email.utils.format_datetime(self.datetime)

     When creating a ‘DateHeader’, 'value' may be *note datetime: 1cc.
     instance.  This means, for example, that the following code is
     valid and does what one would expect:

          msg['Date'] = datetime(2011, 7, 15, 21)

     Because this is a naive ‘datetime’ it will be interpreted as a UTC
     timestamp, and the resulting value will have a timezone of ‘-0000’.
     Much more useful is to use the *note localtime(): 2c4. function
     from the *note utils: 50. module:

          msg['Date'] = utils.localtime()

     This example sets the date header to the current time and date
     using the current timezone offset.

 -- Class: email.headerregistry.AddressHeader

     Address headers are one of the most complex structured header
     types.  The ‘AddressHeader’ class provides a generic interface to
     any address header.

     This header type provides the following additional attributes:

      -- Attribute: groups

          A tuple of *note Group: 381d. objects encoding the addresses
          and groups found in the header value.  Addresses that are not
          part of a group are represented in this list as single-address
          ‘Groups’ whose *note display_name: 381e. is ‘None’.

      -- Attribute: addresses

          A tuple of *note Address: 3820. objects encoding all of the
          individual addresses from the header value.  If the header
          value contains any groups, the individual addresses from the
          group are included in the list at the point where the group
          occurs in the value (that is, the list of addresses is
          “flattened” into a one dimensional list).

     The ‘decoded’ value of the header will have all encoded words
     decoded to unicode.  *note idna: 52. encoded domain names are also
     decoded to unicode.  The ‘decoded’ value is set by *note joining:
     2386. the *note str: 44f. value of the elements of the ‘groups’
     attribute with ‘', '’.

     A list of *note Address: 3820. and *note Group: 381d. objects in
     any combination may be used to set the value of an address header.
     ‘Group’ objects whose ‘display_name’ is ‘None’ will be interpreted
     as single addresses, which allows an address list to be copied with
     groups intact by using the list obtained from the ‘groups’
     attribute of the source header.

 -- Class: email.headerregistry.SingleAddressHeader

     A subclass of *note AddressHeader: 381b. that adds one additional
     attribute:

      -- Attribute: address

          The single address encoded by the header value.  If the header
          value actually contains more than one address (which would be
          a violation of the RFC under the default *note policy: 4f.),
          accessing this attribute will result in a *note ValueError:
          202.

Many of the above classes also have a ‘Unique’ variant (for example,
‘UniqueUnstructuredHeader’).  The only difference is that in the
‘Unique’ variant, *note max_count: 37ef. is set to 1.

 -- Class: email.headerregistry.MIMEVersionHeader

     There is really only one valid value for the ‘MIME-Version’ header,
     and that is ‘1.0’.  For future proofing, this header class supports
     other valid version numbers.  If a version number has a valid value
     per RFC 2045(12), then the header object will have non-‘None’
     values for the following attributes:

      -- Attribute: version

          The version number as a string, with any whitespace and/or
          comments removed.

      -- Attribute: major

          The major version number as an integer

      -- Attribute: minor

          The minor version number as an integer

 -- Class: email.headerregistry.ParameterizedMIMEHeader

     MIME headers all start with the prefix ‘Content-’.  Each specific
     header has a certain value, described under the class for that
     header.  Some can also take a list of supplemental parameters,
     which have a common format.  This class serves as a base for all
     the MIME headers that take parameters.

      -- Attribute: params

          A dictionary mapping parameter names to parameter values.

 -- Class: email.headerregistry.ContentTypeHeader

     A *note ParameterizedMIMEHeader: 3827. class that handles the
     ‘Content-Type’ header.

      -- Attribute: content_type

          The content type string, in the form ‘maintype/subtype’.

      -- Attribute: maintype

      -- Attribute: subtype

 -- Class: email.headerregistry.ContentDispositionHeader

     A *note ParameterizedMIMEHeader: 3827. class that handles the
     ‘Content-Disposition’ header.

      -- Attribute: content_disposition

          ‘inline’ and ‘attachment’ are the only valid values in common
          use.

 -- Class: email.headerregistry.ContentTransferEncodingHeader

     Handles the ‘Content-Transfer-Encoding’ header.

      -- Attribute: cte

          Valid values are ‘7bit’, ‘8bit’, ‘base64’, and
          ‘quoted-printable’.  See RFC 2045(13) for more information.

 -- Class: email.headerregistry.HeaderRegistry (base_class=BaseHeader,
          default_class=UnstructuredHeader, use_default_map=True)

     This is the factory used by *note EmailPolicy: 10fb. by default.
     ‘HeaderRegistry’ builds the class used to create a header instance
     dynamically, using 'base_class' and a specialized class retrieved
     from a registry that it holds.  When a given header name does not
     appear in the registry, the class specified by 'default_class' is
     used as the specialized class.  When 'use_default_map' is ‘True’
     (the default), the standard mapping of header names to classes is
     copied in to the registry during initialization.  'base_class' is
     always the last class in the generated class’s *note __bases__:
     14fb. list.

     The default mappings are:


          subject: UniqueUnstructuredHeader


          date: UniqueDateHeader


          resent-date: DateHeader


          orig-date: UniqueDateHeader


          sender: UniqueSingleAddressHeader


          resent-sender: SingleAddressHeader


          to: UniqueAddressHeader


          resent-to: AddressHeader


          cc: UniqueAddressHeader


          resent-cc: AddressHeader


          bcc: UniqueAddressHeader


          resent-bcc: AddressHeader


          from: UniqueAddressHeader


          resent-from: AddressHeader


          reply-to: UniqueAddressHeader


          mime-version: MIMEVersionHeader


          content-type: ContentTypeHeader


          content-disposition: ContentDispositionHeader


          content-transfer-encoding: ContentTransferEncodingHeader


          message-id: MessageIDHeader

     ‘HeaderRegistry’ has the following methods:

      -- Method: map_to_type (self, name, cls)

          'name' is the name of the header to be mapped.  It will be
          converted to lower case in the registry.  'cls' is the
          specialized class to be used, along with 'base_class', to
          create the class used to instantiate headers that match
          'name'.

      -- Method: __getitem__ (name)

          Construct and return a class to handle creating a 'name'
          header.

      -- Method: __call__ (name, value)

          Retrieves the specialized header associated with 'name' from
          the registry (using 'default_class' if 'name' does not appear
          in the registry) and composes it with 'base_class' to produce
          a class, calls the constructed class’s constructor, passing it
          the same argument list, and finally returns the class instance
          created thereby.

The following classes are the classes used to represent data parsed from
structured headers and can, in general, be used by an application
program to construct structured values to assign to specific headers.

 -- Class: email.headerregistry.Address (display_name='', username='',
          domain='', addr_spec=None)

     The class used to represent an email address.  The general form of
     an address is:

          [display_name] <username@domain>

     or:

          username@domain

     where each part must conform to specific syntax rules spelled out
     in RFC 5322(14).

     As a convenience 'addr_spec' can be specified instead of 'username'
     and 'domain', in which case 'username' and 'domain' will be parsed
     from the 'addr_spec'.  An 'addr_spec' must be a properly RFC quoted
     string; if it is not ‘Address’ will raise an error.  Unicode
     characters are allowed and will be property encoded when
     serialized.  However, per the RFCs, unicode is 'not' allowed in the
     username portion of the address.

      -- Attribute: display_name

          The display name portion of the address, if any, with all
          quoting removed.  If the address does not have a display name,
          this attribute will be an empty string.

      -- Attribute: username

          The ‘username’ portion of the address, with all quoting
          removed.

      -- Attribute: domain

          The ‘domain’ portion of the address.

      -- Attribute: addr_spec

          The ‘username@domain’ portion of the address, correctly quoted
          for use as a bare address (the second form shown above).  This
          attribute is not mutable.

      -- Method: __str__ ()

          The ‘str’ value of the object is the address quoted according
          to RFC 5322(15) rules, but with no Content Transfer Encoding
          of any non-ASCII characters.

     To support SMTP ( RFC 5321(16)), ‘Address’ handles one special
     case: if ‘username’ and ‘domain’ are both the empty string (or
     ‘None’), then the string value of the ‘Address’ is ‘<>’.

 -- Class: email.headerregistry.Group (display_name=None,
          addresses=None)

     The class used to represent an address group.  The general form of
     an address group is:

          display_name: [address-list];

     As a convenience for processing lists of addresses that consist of
     a mixture of groups and single addresses, a ‘Group’ may also be
     used to represent single addresses that are not part of a group by
     setting 'display_name' to ‘None’ and providing a list of the single
     address as 'addresses'.

      -- Attribute: display_name

          The ‘display_name’ of the group.  If it is ‘None’ and there is
          exactly one ‘Address’ in ‘addresses’, then the ‘Group’
          represents a single address that is not in a group.

      -- Attribute: addresses

          A possibly empty tuple of *note Address: 3820. objects
          representing the addresses in the group.

      -- Method: __str__ ()

          The ‘str’ value of a ‘Group’ is formatted according to RFC
          5322(17), but with no Content Transfer Encoding of any
          non-ASCII characters.  If ‘display_name’ is none and there is
          a single ‘Address’ in the ‘addresses’ list, the ‘str’ value
          will be the same as the ‘str’ of that single ‘Address’.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/email/headerregistry.py

   (2) Originally added in 3.3 as a *note provisional module: 107f.

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html

   (4) https://datatracker.ietf.org/doc/html/rfc2047.html

   (5) https://datatracker.ietf.org/doc/html/rfc5322.html

   (6) https://datatracker.ietf.org/doc/html/rfc5322.html

   (7) https://datatracker.ietf.org/doc/html/rfc2047.html

   (8) https://datatracker.ietf.org/doc/html/rfc5322.html

   (9) https://datatracker.ietf.org/doc/html/rfc2047.html

   (10) https://datatracker.ietf.org/doc/html/rfc5322.html

   (11) https://datatracker.ietf.org/doc/html/rfc5322.html

   (12) https://datatracker.ietf.org/doc/html/rfc2045.html

   (13) https://datatracker.ietf.org/doc/html/rfc2045.html

   (14) https://datatracker.ietf.org/doc/html/rfc5322.html

   (15) https://datatracker.ietf.org/doc/html/rfc5322.html

   (16) https://datatracker.ietf.org/doc/html/rfc5321.html

   (17) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: email contentmanager Managing MIME Content,  Next: email Examples,  Prev: email headerregistry Custom Header Objects,  Up: email — An email and MIME handling package

5.20.1.10 ‘email.contentmanager’: Managing MIME Content
.......................................................

'Source code:' Lib/email/contentmanager.py(1)

__________________________________________________________________

Added in version 3.6: (2)

 -- Class: email.contentmanager.ContentManager

     Base class for content managers.  Provides the standard registry
     mechanisms to register converters between MIME content and other
     representations, as well as the ‘get_content’ and ‘set_content’
     dispatch methods.

      -- Method: get_content (msg, *args, **kw)

          Look up a handler function based on the ‘mimetype’ of 'msg'
          (see next paragraph), call it, passing through all arguments,
          and return the result of the call.  The expectation is that
          the handler will extract the payload from 'msg' and return an
          object that encodes information about the extracted data.

          To find the handler, look for the following keys in the
          registry, stopping with the first one found:

             * the string representing the full MIME type
               (‘maintype/subtype’)

             * the string representing the ‘maintype’

             * the empty string

          If none of these keys produce a handler, raise a *note
          KeyError: 345. for the full MIME type.

      -- Method: set_content (msg, obj, *args, **kw)

          If the ‘maintype’ is ‘multipart’, raise a *note TypeError:
          2c3.; otherwise look up a handler function based on the type
          of 'obj' (see next paragraph), call *note clear_content():
          37bf. on the 'msg', and call the handler function, passing
          through all arguments.  The expectation is that the handler
          will transform and store 'obj' into 'msg', possibly making
          other changes to 'msg' as well, such as adding various MIME
          headers to encode information needed to interpret the stored
          data.

          To find the handler, obtain the type of 'obj' (‘typ =
          type(obj)’), and look for the following keys in the registry,
          stopping with the first one found:

             * the type itself (‘typ’)

             * the type’s fully qualified name (‘typ.__module__ + '.' +
               typ.__qualname__’).

             * the type’s *note qualname: 20d5. (‘typ.__qualname__’)

             * the type’s *note name: 14fa. (‘typ.__name__’).

          If none of the above match, repeat all of the checks above for
          each of the types in the *note MRO: 15e6. (*note typ.__mro__:
          20da.).  Finally, if no other key yields a handler, check for
          a handler for the key ‘None’.  If there is no handler for
          ‘None’, raise a *note KeyError: 345. for the fully qualified
          name of the type.

          Also add a ‘MIME-Version’ header if one is not present (see
          also *note MIMEPart: f72.).

      -- Method: add_get_handler (key, handler)

          Record the function 'handler' as the handler for 'key'.  For
          the possible values of 'key', see *note get_content(): 383f.

      -- Method: add_set_handler (typekey, handler)

          Record 'handler' as the function to call when an object of a
          type matching 'typekey' is passed to *note set_content():
          3841.  For the possible values of 'typekey', see
          ‘set_content()’.

* Menu:

* Content Manager Instances::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/email/contentmanager.py

   (2) Originally added in 3.4 as a *note provisional module: 107f.


File: python.info,  Node: Content Manager Instances,  Up: email contentmanager Managing MIME Content

5.20.1.11 Content Manager Instances
...................................

Currently the email package provides only one concrete content manager,
*note raw_data_manager: 37ed, although more may be added in the future.
‘raw_data_manager’ is the *note content_manager: f73. provided by *note
EmailPolicy: 10fb. and its derivatives.

 -- Data: email.contentmanager.raw_data_manager

     This content manager provides only a minimum interface beyond that
     provided by *note Message: 27c. itself: it deals only with text,
     raw byte strings, and ‘Message’ objects.  Nevertheless, it provides
     significant advantages compared to the base API: ‘get_content’ on a
     text part will return a unicode string without the application
     needing to manually decode it, ‘set_content’ provides a rich set of
     options for controlling the headers added to a part and controlling
     the content transfer encoding, and it enables the use of the
     various ‘add_’ methods, thereby simplifying the creation of
     multipart messages.

      -- Method: email.contentmanager.get_content (msg,
               errors='replace')

          Return the payload of the part as either a string (for ‘text’
          parts), an *note EmailMessage: 27b. object (for
          ‘message/rfc822’ parts), or a ‘bytes’ object (for all other
          non-multipart types).  Raise a *note KeyError: 345. if called
          on a ‘multipart’.  If the part is a ‘text’ part and 'errors'
          is specified, use it as the error handler when decoding the
          payload to unicode.  The default error handler is ‘replace’.

      -- Method: email.contentmanager.set_content (msg, <'str'>,
               subtype="plain", charset='utf-8', cte=None,
               disposition=None, filename=None, cid=None, params=None,
               headers=None)

      -- Method: email.contentmanager.set_content (msg, <'bytes'>,
               maintype, subtype, cte="base64", disposition=None,
               filename=None, cid=None, params=None, headers=None)

      -- Method: email.contentmanager.set_content (msg,
               <'EmailMessage'>, cte=None, disposition=None,
               filename=None, cid=None, params=None, headers=None)

          Add headers and payload to 'msg':

          Add a ‘Content-Type’ header with a ‘maintype/subtype’ value.

             * For ‘str’, set the MIME ‘maintype’ to ‘text’, and set the
               subtype to 'subtype' if it is specified, or ‘plain’ if it
               is not.

             * For ‘bytes’, use the specified 'maintype' and 'subtype',
               or raise a *note TypeError: 2c3. if they are not
               specified.

             * For *note EmailMessage: 27b. objects, set the maintype to
               ‘message’, and set the subtype to 'subtype' if it is
               specified or ‘rfc822’ if it is not.  If 'subtype' is
               ‘partial’, raise an error (‘bytes’ objects must be used
               to construct ‘message/partial’ parts).

          If 'charset' is provided (which is valid only for ‘str’),
          encode the string to bytes using the specified character set.
          The default is ‘utf-8’.  If the specified 'charset' is a known
          alias for a standard MIME charset name, use the standard
          charset instead.

          If 'cte' is set, encode the payload using the specified
          content transfer encoding, and set the
          ‘Content-Transfer-Encoding’ header to that value.  Possible
          values for 'cte' are ‘quoted-printable’, ‘base64’, ‘7bit’,
          ‘8bit’, and ‘binary’.  If the input cannot be encoded in the
          specified encoding (for example, specifying a 'cte' of ‘7bit’
          for an input that contains non-ASCII values), raise a *note
          ValueError: 202.

             * For ‘str’ objects, if 'cte' is not set use heuristics to
               determine the most compact encoding.  Prior to encoding,
               *note str.splitlines(): 129d. is used to normalize all
               line boundaries, ensuring that each line of the payload
               is terminated by the current policy’s *note linesep:
               37e0. property (even if the original string did not end
               with one).

             * For ‘bytes’ objects, 'cte' is taken to be base64 if not
               set, and the aforementioned newline translation is not
               performed.

             * For *note EmailMessage: 27b, per RFC 2046(1), raise an
               error if a 'cte' of ‘quoted-printable’ or ‘base64’ is
               requested for 'subtype' ‘rfc822’, and for any 'cte' other
               than ‘7bit’ for 'subtype' ‘external-body’.  For
               ‘message/rfc822’, use ‘8bit’ if 'cte' is not specified.
               For all other values of 'subtype', use ‘7bit’.

               Note: A 'cte' of ‘binary’ does not actually work
               correctly yet.  The ‘EmailMessage’ object as modified by
               ‘set_content’ is correct, but *note BytesGenerator: 1214.
               does not serialize it correctly.

          If 'disposition' is set, use it as the value of the
          ‘Content-Disposition’ header.  If not specified, and
          'filename' is specified, add the header with the value
          ‘attachment’.  If 'disposition' is not specified and
          'filename' is also not specified, do not add the header.  The
          only valid values for 'disposition' are ‘attachment’ and
          ‘inline’.

          If 'filename' is specified, use it as the value of the
          ‘filename’ parameter of the ‘Content-Disposition’ header.

          If 'cid' is specified, add a ‘Content-ID’ header with 'cid' as
          its value.

          If 'params' is specified, iterate its ‘items’ method and use
          the resulting ‘(key, value)’ pairs to set additional
          parameters on the ‘Content-Type’ header.

          If 'headers' is specified and is a list of strings of the form
          ‘headername: headervalue’ or a list of ‘header’ objects
          (distinguished from strings by having a ‘name’ attribute), add
          the headers to 'msg'.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2046.html


File: python.info,  Node: email Examples,  Next: email message Message Representing an email message using the compat32 API,  Prev: email contentmanager Managing MIME Content,  Up: email — An email and MIME handling package

5.20.1.12 ‘email’: Examples
...........................

Here are a few examples of how to use the *note email: 3b. package to
read, write, and send simple email messages, as well as more complex
MIME messages.

First, let’s see how to create and send a simple text message (both the
text content and the addresses may contain unicode characters):

     # Import smtplib for the actual sending function
     import smtplib

     # Import the email modules we'll need
     from email.message import EmailMessage

     # Open the plain text file whose name is in textfile for reading.
     with open(textfile) as fp:
         # Create a text/plain message
         msg = EmailMessage()
         msg.set_content(fp.read())

     # me == the sender's email address
     # you == the recipient's email address
     msg['Subject'] = f'The contents of {textfile}'
     msg['From'] = me
     msg['To'] = you

     # Send the message via our own SMTP server.
     s = smtplib.SMTP('localhost')
     s.send_message(msg)
     s.quit()

Parsing RFC 822(1) headers can easily be done by the using the classes
from the *note parser: 4e. module:

     # Import the email modules we'll need
     #from email.parser import BytesParser
     from email.parser import Parser
     from email.policy import default

     # If the e-mail headers are in a file, uncomment these two lines:
     # with open(messagefile, 'rb') as fp:
     #     headers = BytesParser(policy=default).parse(fp)

     #  Or for parsing headers in a string (this is an uncommon operation), use:
     headers = Parser(policy=default).parsestr(
             'From: Foo Bar <user@example.com>\n'
             'To: <someone_else@example.com>\n'
             'Subject: Test message\n'
             '\n'
             'Body would go here\n')

     #  Now the header items can be accessed as a dictionary:
     print('To: {}'.format(headers['to']))
     print('From: {}'.format(headers['from']))
     print('Subject: {}'.format(headers['subject']))

     # You can also access the parts of the addresses:
     print('Recipient username: {}'.format(headers['to'].addresses[0].username))
     print('Sender name: {}'.format(headers['from'].addresses[0].display_name))

Here’s an example of how to send a MIME message containing a bunch of
family pictures that may be residing in a directory:

     # Import smtplib for the actual sending function.
     import smtplib

     # Here are the email package modules we'll need.
     from email.message import EmailMessage

     # Create the container email message.
     msg = EmailMessage()
     msg['Subject'] = 'Our family reunion'
     # me == the sender's email address
     # family = the list of all recipients' email addresses
     msg['From'] = me
     msg['To'] = ', '.join(family)
     msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'

     # Open the files in binary mode.  You can also omit the subtype
     # if you want MIMEImage to guess it.
     for file in pngfiles:
         with open(file, 'rb') as fp:
             img_data = fp.read()
         msg.add_attachment(img_data, maintype='image',
                                      subtype='png')

     # Send the email via our own SMTP server.
     with smtplib.SMTP('localhost') as s:
         s.send_message(msg)

Here’s an example of how to send the entire contents of a directory as
an email message: (2)

     #!/usr/bin/env python3

     """Send the contents of a directory as a MIME message."""

     import os
     import smtplib
     # For guessing MIME type based on file name extension
     import mimetypes

     from argparse import ArgumentParser

     from email.message import EmailMessage
     from email.policy import SMTP


     def main():
         parser = ArgumentParser(description="""\
     Send the contents of a directory as a MIME message.
     Unless the -o option is given, the email is sent by forwarding to your local
     SMTP server, which then does the normal delivery process.  Your local machine
     must be running an SMTP server.
     """)
         parser.add_argument('-d', '--directory',
                             help="""Mail the contents of the specified directory,
                             otherwise use the current directory.  Only the regular
                             files in the directory are sent, and we don't recurse to
                             subdirectories.""")
         parser.add_argument('-o', '--output',
                             metavar='FILE',
                             help="""Print the composed message to FILE instead of
                             sending the message to the SMTP server.""")
         parser.add_argument('-s', '--sender', required=True,
                             help='The value of the From: header (required)')
         parser.add_argument('-r', '--recipient', required=True,
                             action='append', metavar='RECIPIENT',
                             default=[], dest='recipients',
                             help='A To: header value (at least one required)')
         args = parser.parse_args()
         directory = args.directory
         if not directory:
             directory = '.'
         # Create the message
         msg = EmailMessage()
         msg['Subject'] = f'Contents of directory {os.path.abspath(directory)}'
         msg['To'] = ', '.join(args.recipients)
         msg['From'] = args.sender
         msg.preamble = 'You will not see this in a MIME-aware mail reader.\n'

         for filename in os.listdir(directory):
             path = os.path.join(directory, filename)
             if not os.path.isfile(path):
                 continue
             # Guess the content type based on the file's extension.  Encoding
             # will be ignored, although we should check for simple things like
             # gzip'd or compressed files.
             ctype, encoding = mimetypes.guess_file_type(path)
             if ctype is None or encoding is not None:
                 # No guess could be made, or the file is encoded (compressed), so
                 # use a generic bag-of-bits type.
                 ctype = 'application/octet-stream'
             maintype, subtype = ctype.split('/', 1)
             with open(path, 'rb') as fp:
                 msg.add_attachment(fp.read(),
                                    maintype=maintype,
                                    subtype=subtype,
                                    filename=filename)
         # Now send or store the message
         if args.output:
             with open(args.output, 'wb') as fp:
                 fp.write(msg.as_bytes(policy=SMTP))
         else:
             with smtplib.SMTP('localhost') as s:
                 s.send_message(msg)


     if __name__ == '__main__':
         main()

Here’s an example of how to unpack a MIME message like the one above,
into a directory of files:

     #!/usr/bin/env python3

     """Unpack a MIME message into a directory of files."""

     import os
     import email
     import mimetypes

     from email.policy import default

     from argparse import ArgumentParser


     def main():
         parser = ArgumentParser(description="""\
     Unpack a MIME message into a directory of files.
     """)
         parser.add_argument('-d', '--directory', required=True,
                             help="""Unpack the MIME message into the named
                             directory, which will be created if it doesn't already
                             exist.""")
         parser.add_argument('msgfile')
         args = parser.parse_args()

         with open(args.msgfile, 'rb') as fp:
             msg = email.message_from_binary_file(fp, policy=default)

         try:
             os.mkdir(args.directory)
         except FileExistsError:
             pass

         counter = 1
         for part in msg.walk():
             # multipart/* are just containers
             if part.get_content_maintype() == 'multipart':
                 continue
             # Applications should really sanitize the given filename so that an
             # email message can't be used to overwrite important files
             filename = part.get_filename()
             if not filename:
                 ext = mimetypes.guess_extension(part.get_content_type())
                 if not ext:
                     # Use a generic bag-of-bits extension
                     ext = '.bin'
                 filename = f'part-{counter:03d}{ext}'
             counter += 1
             with open(os.path.join(args.directory, filename), 'wb') as fp:
                 fp.write(part.get_payload(decode=True))


     if __name__ == '__main__':
         main()

Here’s an example of how to create an HTML message with an alternative
plain text version.  To make things a bit more interesting, we include a
related image in the html part, and we save a copy of what we are going
to send to disk, as well as sending it.

     #!/usr/bin/env python3

     import smtplib

     from email.message import EmailMessage
     from email.headerregistry import Address
     from email.utils import make_msgid

     # Create the base text message.
     msg = EmailMessage()
     msg['Subject'] = "Pourquoi pas des asperges pour ce midi ?"
     msg['From'] = Address("Pepé Le Pew", "pepe", "example.com")
     msg['To'] = (Address("Penelope Pussycat", "penelope", "example.com"),
                  Address("Fabrette Pussycat", "fabrette", "example.com"))
     msg.set_content("""\
     Salut!

     Cette recette [1] sera sûrement un très bon repas.

     [1] http://www.yummly.com/recipe/Roasted-Asparagus-Epicurious-203718

     --Pepé
     """)

     # Add the html version.  This converts the message into a multipart/alternative
     # container, with the original text message as the first part and the new html
     # message as the second part.
     asparagus_cid = make_msgid()
     msg.add_alternative("""\
     <html>
       <head></head>
       <body>
         <p>Salut!</p>
         <p>Cette
             <a href="http://www.yummly.com/recipe/Roasted-Asparagus-Epicurious-203718">
                 recette
             </a> sera sûrement un très bon repas.
         </p>
         <img src="cid:{asparagus_cid}">
       </body>
     </html>
     """.format(asparagus_cid=asparagus_cid[1:-1]), subtype='html')
     # note that we needed to peel the <> off the msgid for use in the html.

     # Now add the related image to the html part.
     with open("roasted-asparagus.jpg", 'rb') as img:
         msg.get_payload()[1].add_related(img.read(), 'image', 'jpeg',
                                          cid=asparagus_cid)

     # Make a local copy of what we are going to send.
     with open('outgoing.msg', 'wb') as f:
         f.write(bytes(msg))

     # Send the message via local SMTP server.
     with smtplib.SMTP('localhost') as s:
         s.send_message(msg)

If we were sent the message from the last example, here is one way we
could process it:

     import os
     import sys
     import tempfile
     import mimetypes
     import webbrowser

     # Import the email modules we'll need
     from email import policy
     from email.parser import BytesParser


     def magic_html_parser(html_text, partfiles):
         """Return safety-sanitized html linked to partfiles.

         Rewrite the href="cid:...." attributes to point to the filenames in partfiles.
         Though not trivial, this should be possible using html.parser.
         """
         raise NotImplementedError("Add the magic needed")


     # In a real program you'd get the filename from the arguments.
     with open('outgoing.msg', 'rb') as fp:
         msg = BytesParser(policy=policy.default).parse(fp)

     # Now the header items can be accessed as a dictionary, and any non-ASCII will
     # be converted to unicode:
     print('To:', msg['to'])
     print('From:', msg['from'])
     print('Subject:', msg['subject'])

     # If we want to print a preview of the message content, we can extract whatever
     # the least formatted payload is and print the first three lines.  Of course,
     # if the message has no plain text part printing the first three lines of html
     # is probably useless, but this is just a conceptual example.
     simplest = msg.get_body(preferencelist=('plain', 'html'))
     print()
     print(''.join(simplest.get_content().splitlines(keepends=True)[:3]))

     ans = input("View full message?")
     if ans.lower()[0] == 'n':
         sys.exit()

     # We can extract the richest alternative in order to display it:
     richest = msg.get_body()
     partfiles = {}
     if richest['content-type'].maintype == 'text':
         if richest['content-type'].subtype == 'plain':
             for line in richest.get_content().splitlines():
                 print(line)
             sys.exit()
         elif richest['content-type'].subtype == 'html':
             body = richest
         else:
             print("Don't know how to display {}".format(richest.get_content_type()))
             sys.exit()
     elif richest['content-type'].content_type == 'multipart/related':
         body = richest.get_body(preferencelist=('html'))
         for part in richest.iter_attachments():
             fn = part.get_filename()
             if fn:
                 extension = os.path.splitext(part.get_filename())[1]
             else:
                 extension = mimetypes.guess_extension(part.get_content_type())
             with tempfile.NamedTemporaryFile(suffix=extension, delete=False) as f:
                 f.write(part.get_content())
                 # again strip the <> to go from email form of cid to html form.
                 partfiles[part['content-id'][1:-1]] = f.name
     else:
         print("Don't know how to display {}".format(richest.get_content_type()))
         sys.exit()
     with tempfile.NamedTemporaryFile(mode='w', delete=False) as f:
         f.write(magic_html_parser(body.get_content(), partfiles))
     webbrowser.open(f.name)
     os.remove(f.name)
     for fn in partfiles.values():
         os.remove(fn)

     # Of course, there are lots of email messages that could break this simple
     # minded program, but it will handle the most common ones.

Up to the prompt, the output from the above is:

     To: Penelope Pussycat <penelope@example.com>, Fabrette Pussycat <fabrette@example.com>
     From: Pepé Le Pew <pepe@example.com>
     Subject: Pourquoi pas des asperges pour ce midi ?

     Salut!

     Cette recette [1] sera sûrement un très bon repas.

Legacy API:

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc822.html

   (2) Thanks to Matthew Dixon Cowles for the original inspiration and
examples.


File: python.info,  Node: email message Message Representing an email message using the compat32 API,  Next: email mime Creating email and MIME objects from scratch,  Prev: email Examples,  Up: email — An email and MIME handling package

5.20.1.13 ‘email.message.Message’: Representing an email message using the ‘compat32’ API
.........................................................................................

The *note Message: 27c. class is very similar to the *note EmailMessage:
27b. class, without the methods added by that class, and with the
default behavior of certain other methods being slightly different.  We
also document here some methods that, while supported by the
‘EmailMessage’ class, are not recommended unless you are dealing with
legacy code.

The philosophy and structure of the two classes is otherwise the same.

This document describes the behavior under the default (for *note
Message: 27c.) policy *note Compat32: 10f8.  If you are going to use
another policy, you should be using the *note EmailMessage: 27b. class
instead.

An email message consists of 'headers' and a 'payload'.  Headers must be
RFC 5322(1) style names and values, where the field name and value are
separated by a colon.  The colon is not part of either the field name or
the field value.  The payload may be a simple text message, or a binary
object, or a structured sequence of sub-messages each with their own set
of headers and their own payload.  The latter type of payload is
indicated by the message having a MIME type such as ‘multipart/*’ or
‘message/rfc822’.

The conceptual model provided by a *note Message: 27c. object is that of
an ordered dictionary of headers with additional methods for accessing
both specialized information from the headers, for accessing the
payload, for generating a serialized version of the message, and for
recursively walking over the object tree.  Note that duplicate headers
are supported but special methods must be used to access them.

The *note Message: 27c. pseudo-dictionary is indexed by the header
names, which must be ASCII values.  The values of the dictionary are
strings that are supposed to contain only ASCII characters; there is
some special handling for non-ASCII input, but it doesn’t always produce
the correct results.  Headers are stored and returned in case-preserving
form, but field names are matched case-insensitively.  There may also be
a single envelope header, also known as the 'Unix-From' header or the
‘From_’ header.  The 'payload' is either a string or bytes, in the case
of simple message objects, or a list of ‘Message’ objects, for MIME
container documents (e.g.  ‘multipart/*’ and ‘message/rfc822’).

Here are the methods of the *note Message: 27c. class:

 -- Class: email.message.Message (policy=compat32)

     If 'policy' is specified (it must be an instance of a *note policy:
     4f. class) use the rules it specifies to update and serialize the
     representation of the message.  If 'policy' is not set, use the
     *note compat32: 10f8. policy, which maintains backward
     compatibility with the Python 3.2 version of the email package.
     For more information see the ‘policy’ documentation.

     Changed in version 3.3: The 'policy' keyword argument was added.

      -- Method: as_string (unixfrom=False, maxheaderlen=0, policy=None)

          Return the entire message flattened as a string.  When
          optional 'unixfrom' is true, the envelope header is included
          in the returned string.  'unixfrom' defaults to ‘False’.  For
          backward compatibility reasons, 'maxheaderlen' defaults to
          ‘0’, so if you want a different value you must override it
          explicitly (the value specified for 'max_line_length' in the
          policy will be ignored by this method).  The 'policy' argument
          may be used to override the default policy obtained from the
          message instance.  This can be used to control some of the
          formatting produced by the method, since the specified
          'policy' will be passed to the ‘Generator’.

          Flattening the message may trigger changes to the ‘Message’ if
          defaults need to be filled in to complete the transformation
          to a string (for example, MIME boundaries may be generated or
          modified).

          Note that this method is provided as a convenience and may not
          always format the message the way you want.  For example, by
          default it does not do the mangling of lines that begin with
          ‘From’ that is required by the Unix mbox format.  For more
          flexibility, instantiate a *note Generator: 1213. instance and
          use its *note flatten(): 37da. method directly.  For example:

               from io import StringIO
               from email.generator import Generator
               fp = StringIO()
               g = Generator(fp, mangle_from_=True, maxheaderlen=60)
               g.flatten(msg)
               text = fp.getvalue()

          If the message object contains binary data that is not encoded
          according to RFC standards, the non-compliant data will be
          replaced by unicode “unknown character” code points.  (See
          also *note as_bytes(): f6f. and *note BytesGenerator: 1214.)

          Changed in version 3.4: the 'policy' keyword argument was
          added.

      -- Method: __str__ ()

          Equivalent to *note as_string(): f6e.  Allows ‘str(msg)’ to
          produce a string containing the formatted message.

      -- Method: as_bytes (unixfrom=False, policy=None)

          Return the entire message flattened as a bytes object.  When
          optional 'unixfrom' is true, the envelope header is included
          in the returned string.  'unixfrom' defaults to ‘False’.  The
          'policy' argument may be used to override the default policy
          obtained from the message instance.  This can be used to
          control some of the formatting produced by the method, since
          the specified 'policy' will be passed to the ‘BytesGenerator’.

          Flattening the message may trigger changes to the ‘Message’ if
          defaults need to be filled in to complete the transformation
          to a string (for example, MIME boundaries may be generated or
          modified).

          Note that this method is provided as a convenience and may not
          always format the message the way you want.  For example, by
          default it does not do the mangling of lines that begin with
          ‘From’ that is required by the Unix mbox format.  For more
          flexibility, instantiate a *note BytesGenerator: 1214.
          instance and use its *note flatten(): 37d6. method directly.
          For example:

               from io import BytesIO
               from email.generator import BytesGenerator
               fp = BytesIO()
               g = BytesGenerator(fp, mangle_from_=True, maxheaderlen=60)
               g.flatten(msg)
               text = fp.getvalue()

          Added in version 3.4.

      -- Method: __bytes__ ()

          Equivalent to *note as_bytes(): f6f.  Allows ‘bytes(msg)’ to
          produce a bytes object containing the formatted message.

          Added in version 3.4.

      -- Method: is_multipart ()

          Return ‘True’ if the message’s payload is a list of
          sub-‘Message’ objects, otherwise return ‘False’.  When
          ‘is_multipart()’ returns ‘False’, the payload should be a
          string object (which might be a CTE encoded binary payload).
          (Note that ‘is_multipart()’ returning ‘True’ does not
          necessarily mean that “msg.get_content_maintype() ==
          ‘multipart’” will return the ‘True’.  For example,
          ‘is_multipart’ will return ‘True’ when the ‘Message’ is of
          type ‘message/rfc822’.)

      -- Method: set_unixfrom (unixfrom)

          Set the message’s envelope header to 'unixfrom', which should
          be a string.

      -- Method: get_unixfrom ()

          Return the message’s envelope header.  Defaults to ‘None’ if
          the envelope header was never set.

      -- Method: attach (payload)

          Add the given 'payload' to the current payload, which must be
          ‘None’ or a list of ‘Message’ objects before the call.  After
          the call, the payload will always be a list of ‘Message’
          objects.  If you want to set the payload to a scalar object
          (e.g.  a string), use *note set_payload(): 384c. instead.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by *note set_content():
          1a03. and the related ‘make’ and ‘add’ methods.

      -- Method: get_payload (i=None, decode=False)

          Return the current payload, which will be a list of ‘Message’
          objects when *note is_multipart(): 37ae. is ‘True’, or a
          string when ‘is_multipart()’ is ‘False’.  If the payload is a
          list and you mutate the list object, you modify the message’s
          payload in place.

          With optional argument 'i', ‘get_payload()’ will return the
          'i'-th element of the payload, counting from zero, if *note
          is_multipart(): 37ae. is ‘True’.  An *note IndexError: 1585.
          will be raised if 'i' is less than 0 or greater than or equal
          to the number of items in the payload.  If the payload is a
          string (i.e.  ‘is_multipart()’ is ‘False’) and 'i' is given, a
          *note TypeError: 2c3. is raised.

          Optional 'decode' is a flag indicating whether the payload
          should be decoded or not, according to the
          ‘Content-Transfer-Encoding’ header.  When ‘True’ and the
          message is not a multipart, the payload will be decoded if
          this header’s value is ‘quoted-printable’ or ‘base64’.  If
          some other encoding is used, or ‘Content-Transfer-Encoding’
          header is missing, the payload is returned as-is (undecoded).
          In all cases the returned value is binary data.  If the
          message is a multipart and the 'decode' flag is ‘True’, then
          ‘None’ is returned.  If the payload is base64 and it was not
          perfectly formed (missing padding, characters outside the
          base64 alphabet), then an appropriate defect will be added to
          the message’s defect property (*note
          InvalidBase64PaddingDefect: 380d. or *note
          InvalidBase64CharactersDefect: 380e, respectively).

          When 'decode' is ‘False’ (the default) the body is returned as
          a string without decoding the ‘Content-Transfer-Encoding’.
          However, for a ‘Content-Transfer-Encoding’ of 8bit, an attempt
          is made to decode the original bytes using the ‘charset’
          specified by the ‘Content-Type’ header, using the ‘replace’
          error handler.  If no ‘charset’ is specified, or if the
          ‘charset’ given is not recognized by the email package, the
          body is decoded using the default ASCII charset.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by *note get_content():
          37b4. and *note iter_parts(): 37b3.

      -- Method: set_payload (payload, charset=None)

          Set the entire message object’s payload to 'payload'.  It is
          the client’s responsibility to ensure the payload invariants.
          Optional 'charset' sets the message’s default character set;
          see *note set_charset(): 384d. for details.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by *note set_content():
          1a03.

      -- Method: set_charset (charset)

          Set the character set of the payload to 'charset', which can
          either be a *note Charset: e2c. instance (see *note
          email.charset: 3c.), a string naming a character set, or
          ‘None’.  If it is a string, it will be converted to a
          ‘Charset’ instance.  If 'charset' is ‘None’, the ‘charset’
          parameter will be removed from the ‘Content-Type’ header (the
          message will not be otherwise modified).  Anything else will
          generate a *note TypeError: 2c3.

          If there is no existing ‘MIME-Version’ header one will be
          added.  If there is no existing ‘Content-Type’ header, one
          will be added with a value of ‘text/plain’.  Whether the
          ‘Content-Type’ header already exists or not, its ‘charset’
          parameter will be set to 'charset.output_charset'.  If
          'charset.input_charset' and 'charset.output_charset' differ,
          the payload will be re-encoded to the 'output_charset'.  If
          there is no existing ‘Content-Transfer-Encoding’ header, then
          the payload will be transfer-encoded, if needed, using the
          specified *note Charset: e2c, and a header with the
          appropriate value will be added.  If a
          ‘Content-Transfer-Encoding’ header already exists, the payload
          is assumed to already be correctly encoded using that
          ‘Content-Transfer-Encoding’ and is not modified.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by the 'charset' parameter
          of the *note email.message.EmailMessage.set_content(): 1a03.
          method.

      -- Method: get_charset ()

          Return the *note Charset: e2c. instance associated with the
          message’s payload.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class it always returns ‘None’.

     The following methods implement a mapping-like interface for
     accessing the message’s RFC 2822(2) headers.  Note that there are
     some semantic differences between these methods and a normal
     mapping (i.e.  dictionary) interface.  For example, in a dictionary
     there are no duplicate keys, but here there may be duplicate
     message headers.  Also, in dictionaries there is no guaranteed
     order to the keys returned by *note keys(): 384f, but in a
     ‘Message’ object, headers are always returned in the order they
     appeared in the original message, or were added to the message
     later.  Any header deleted and then re-added are always appended to
     the end of the header list.

     These semantic differences are intentional and are biased toward
     maximal convenience.

     Note that in all cases, any envelope header present in the message
     is not included in the mapping interface.

     In a model generated from bytes, any header values that (in
     contravention of the RFCs) contain non-ASCII bytes will, when
     retrieved through this interface, be represented as *note Header:
     1a04. objects with a charset of ‘unknown-8bit’.

      -- Method: __len__ ()

          Return the total number of headers, including duplicates.

      -- Method: __contains__ (name)

          Return ‘True’ if the message object has a field named 'name'.
          Matching is done case-insensitively and 'name' should not
          include the trailing colon.  Used for the ‘in’ operator, e.g.:

               if 'message-id' in myMessage:
                  print('Message-ID:', myMessage['message-id'])

      -- Method: __getitem__ (name)

          Return the value of the named header field.  'name' should not
          include the colon field separator.  If the header is missing,
          ‘None’ is returned; a *note KeyError: 345. is never raised.

          Note that if the named field appears more than once in the
          message’s headers, exactly which of those field values will be
          returned is undefined.  Use the *note get_all(): 3852. method
          to get the values of all the extant named headers.

      -- Method: __setitem__ (name, val)

          Add a header to the message with field name 'name' and value
          'val'.  The field is appended to the end of the message’s
          existing fields.

          Note that this does 'not' overwrite or delete any existing
          header with the same name.  If you want to ensure that the new
          header is the only one present in the message with field name
          'name', delete the field first, e.g.:

               del msg['subject']
               msg['subject'] = 'Python roolz!'

      -- Method: __delitem__ (name)

          Delete all occurrences of the field with name 'name' from the
          message’s headers.  No exception is raised if the named field
          isn’t present in the headers.

      -- Method: keys ()

          Return a list of all the message’s header field names.

      -- Method: values ()

          Return a list of all the message’s field values.

      -- Method: items ()

          Return a list of 2-tuples containing all the message’s field
          headers and values.

      -- Method: get (name, failobj=None)

          Return the value of the named header field.  This is identical
          to *note __getitem__(): 283. except that optional 'failobj' is
          returned if the named header is missing (defaults to ‘None’).

     Here are some additional useful methods:

      -- Method: get_all (name, failobj=None)

          Return a list of all the values for the field named 'name'.
          If there are no such named headers in the message, 'failobj'
          is returned (defaults to ‘None’).

      -- Method: add_header (_name, _value, **_params)

          Extended header setting.  This method is similar to *note
          __setitem__(): 3853. except that additional header parameters
          can be provided as keyword arguments.  '_name' is the header
          field to add and '_value' is the 'primary' value for the
          header.

          For each item in the keyword argument dictionary '_params',
          the key is taken as the parameter name, with underscores
          converted to dashes (since dashes are illegal in Python
          identifiers).  Normally, the parameter will be added as
          ‘key="value"’ unless the value is ‘None’, in which case only
          the key will be added.  If the value contains non-ASCII
          characters, it can be specified as a three tuple in the format
          ‘(CHARSET, LANGUAGE, VALUE)’, where ‘CHARSET’ is a string
          naming the charset to be used to encode the value, ‘LANGUAGE’
          can usually be set to ‘None’ or the empty string (see RFC
          2231(3) for other possibilities), and ‘VALUE’ is the string
          value containing non-ASCII code points.  If a three tuple is
          not passed and the value contains non-ASCII characters, it is
          automatically encoded in RFC 2231(4) format using a ‘CHARSET’
          of ‘utf-8’ and a ‘LANGUAGE’ of ‘None’.

          Here’s an example:

               msg.add_header('Content-Disposition', 'attachment', filename='bud.gif')

          This will add a header that looks like

               Content-Disposition: attachment; filename="bud.gif"

          An example with non-ASCII characters:

               msg.add_header('Content-Disposition', 'attachment',
                              filename=('iso-8859-1', '', 'Fußballer.ppt'))

          Which produces

               Content-Disposition: attachment; filename*="iso-8859-1''Fu%DFballer.ppt"

      -- Method: replace_header (_name, _value)

          Replace a header.  Replace the first header found in the
          message that matches '_name', retaining header order and field
          name case.  If no matching header was found, a *note KeyError:
          345. is raised.

      -- Method: get_content_type ()

          Return the message’s content type.  The returned string is
          coerced to lower case of the form ‘maintype/subtype’.  If
          there was no ‘Content-Type’ header in the message the default
          type as given by *note get_default_type(): 385b. will be
          returned.  Since according to RFC 2045(5), messages always
          have a default type, ‘get_content_type()’ will always return a
          value.

          RFC 2045(6) defines a message’s default type to be
          ‘text/plain’ unless it appears inside a ‘multipart/digest’
          container, in which case it would be ‘message/rfc822’.  If the
          ‘Content-Type’ header has an invalid type specification, RFC
          2045(7) mandates that the default type be ‘text/plain’.

      -- Method: get_content_maintype ()

          Return the message’s main content type.  This is the
          ‘maintype’ part of the string returned by *note
          get_content_type(): 385a.

      -- Method: get_content_subtype ()

          Return the message’s sub-content type.  This is the ‘subtype’
          part of the string returned by *note get_content_type(): 385a.

      -- Method: get_default_type ()

          Return the default content type.  Most messages have a default
          content type of ‘text/plain’, except for messages that are
          subparts of ‘multipart/digest’ containers.  Such subparts have
          a default content type of ‘message/rfc822’.

      -- Method: set_default_type (ctype)

          Set the default content type.  'ctype' should either be
          ‘text/plain’ or ‘message/rfc822’, although this is not
          enforced.  The default content type is not stored in the
          ‘Content-Type’ header.

      -- Method: get_params (failobj=None, header='content-type',
               unquote=True)

          Return the message’s ‘Content-Type’ parameters, as a list.
          The elements of the returned list are 2-tuples of key/value
          pairs, as split on the ‘'='’ sign.  The left hand side of the
          ‘'='’ is the key, while the right hand side is the value.  If
          there is no ‘'='’ sign in the parameter the value is the empty
          string, otherwise the value is as described in *note
          get_param(): 3860. and is unquoted if optional 'unquote' is
          ‘True’ (the default).

          Optional 'failobj' is the object to return if there is no
          ‘Content-Type’ header.  Optional 'header' is the header to
          search instead of ‘Content-Type’.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by the 'params' property
          of the individual header objects returned by the header access
          methods.

      -- Method: get_param (param, failobj=None, header='content-type',
               unquote=True)

          Return the value of the ‘Content-Type’ header’s parameter
          'param' as a string.  If the message has no ‘Content-Type’
          header or if there is no such parameter, then 'failobj' is
          returned (defaults to ‘None’).

          Optional 'header' if given, specifies the message header to
          use instead of ‘Content-Type’.

          Parameter keys are always compared case insensitively.  The
          return value can either be a string, or a 3-tuple if the
          parameter was RFC 2231(8) encoded.  When it’s a 3-tuple, the
          elements of the value are of the form ‘(CHARSET, LANGUAGE,
          VALUE)’.  Note that both ‘CHARSET’ and ‘LANGUAGE’ can be
          ‘None’, in which case you should consider ‘VALUE’ to be
          encoded in the ‘us-ascii’ charset.  You can usually ignore
          ‘LANGUAGE’.

          If your application doesn’t care whether the parameter was
          encoded as in RFC 2231(9), you can collapse the parameter
          value by calling *note email.utils.collapse_rfc2231_value():
          3861, passing in the return value from ‘get_param()’.  This
          will return a suitably decoded Unicode string when the value
          is a tuple, or the original string unquoted if it isn’t.  For
          example:

               rawparam = msg.get_param('foo')
               param = email.utils.collapse_rfc2231_value(rawparam)

          In any case, the parameter value (either the returned string,
          or the ‘VALUE’ item in the 3-tuple) is always unquoted, unless
          'unquote' is set to ‘False’.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by the 'params' property
          of the individual header objects returned by the header access
          methods.

      -- Method: set_param (param, value, header='Content-Type',
               requote=True, charset=None, language='', replace=False)

          Set a parameter in the ‘Content-Type’ header.  If the
          parameter already exists in the header, its value will be
          replaced with 'value'.  If the ‘Content-Type’ header as not
          yet been defined for this message, it will be set to
          ‘text/plain’ and the new parameter value will be appended as
          per RFC 2045(10).

          Optional 'header' specifies an alternative header to
          ‘Content-Type’, and all parameters will be quoted as necessary
          unless optional 'requote' is ‘False’ (the default is ‘True’).

          If optional 'charset' is specified, the parameter will be
          encoded according to RFC 2231(11).  Optional 'language'
          specifies the RFC 2231 language, defaulting to the empty
          string.  Both 'charset' and 'language' should be strings.

          If 'replace' is ‘False’ (the default) the header is moved to
          the end of the list of headers.  If 'replace' is ‘True’, the
          header will be updated in place.

          Changed in version 3.4: ‘replace’ keyword was added.

      -- Method: del_param (param, header='content-type', requote=True)

          Remove the given parameter completely from the ‘Content-Type’
          header.  The header will be re-written in place without the
          parameter or its value.  All values will be quoted as
          necessary unless 'requote' is ‘False’ (the default is ‘True’).
          Optional 'header' specifies an alternative to ‘Content-Type’.

      -- Method: set_type (type, header='Content-Type', requote=True)

          Set the main type and subtype for the ‘Content-Type’ header.
          'type' must be a string in the form ‘maintype/subtype’,
          otherwise a *note ValueError: 202. is raised.

          This method replaces the ‘Content-Type’ header, keeping all
          the parameters in place.  If 'requote' is ‘False’, this leaves
          the existing header’s quoting as is, otherwise the parameters
          will be quoted (the default).

          An alternative header can be specified in the 'header'
          argument.  When the ‘Content-Type’ header is set a
          ‘MIME-Version’ header is also added.

          This is a legacy method.  On the *note EmailMessage: 27b.
          class its functionality is replaced by the ‘make_’ and ‘add_’
          methods.

      -- Method: get_filename (failobj=None)

          Return the value of the ‘filename’ parameter of the
          ‘Content-Disposition’ header of the message.  If the header
          does not have a ‘filename’ parameter, this method falls back
          to looking for the ‘name’ parameter on the ‘Content-Type’
          header.  If neither is found, or the header is missing, then
          'failobj' is returned.  The returned string will always be
          unquoted as per *note email.utils.unquote(): 37a7.

      -- Method: get_boundary (failobj=None)

          Return the value of the ‘boundary’ parameter of the
          ‘Content-Type’ header of the message, or 'failobj' if either
          the header is missing, or has no ‘boundary’ parameter.  The
          returned string will always be unquoted as per *note
          email.utils.unquote(): 37a7.

      -- Method: set_boundary (boundary)

          Set the ‘boundary’ parameter of the ‘Content-Type’ header to
          'boundary'.  ‘set_boundary()’ will always quote 'boundary' if
          necessary.  A *note HeaderParseError: 37aa. is raised if the
          message object has no ‘Content-Type’ header.

          Note that using this method is subtly different than deleting
          the old ‘Content-Type’ header and adding a new one with the
          new boundary via *note add_header(): 3858, because
          ‘set_boundary()’ preserves the order of the ‘Content-Type’
          header in the list of headers.  However, it does 'not'
          preserve any continuation lines which may have been present in
          the original ‘Content-Type’ header.

      -- Method: get_content_charset (failobj=None)

          Return the ‘charset’ parameter of the ‘Content-Type’ header,
          coerced to lower case.  If there is no ‘Content-Type’ header,
          or if that header has no ‘charset’ parameter, 'failobj' is
          returned.

          Note that this method differs from *note get_charset(): 384e.
          which returns the *note Charset: e2c. instance for the default
          encoding of the message body.

      -- Method: get_charsets (failobj=None)

          Return a list containing the character set names in the
          message.  If the message is a ‘multipart’, then the list will
          contain one element for each subpart in the payload,
          otherwise, it will be a list of length 1.

          Each item in the list will be a string which is the value of
          the ‘charset’ parameter in the ‘Content-Type’ header for the
          represented subpart.  However, if the subpart has no
          ‘Content-Type’ header, no ‘charset’ parameter, or is not of
          the ‘text’ main MIME type, then that item in the returned list
          will be 'failobj'.

      -- Method: get_content_disposition ()

          Return the lowercased value (without parameters) of the
          message’s ‘Content-Disposition’ header if it has one, or
          ‘None’.  The possible values for this method are 'inline',
          'attachment' or ‘None’ if the message follows RFC 2183(12).

          Added in version 3.5.

      -- Method: walk ()

          The ‘walk()’ method is an all-purpose generator which can be
          used to iterate over all the parts and subparts of a message
          object tree, in depth-first traversal order.  You will
          typically use ‘walk()’ as the iterator in a ‘for’ loop; each
          iteration returns the next subpart.

          Here’s an example that prints the MIME type of every part of a
          multipart message structure:

               >>> for part in msg.walk():
               ...     print(part.get_content_type())
               multipart/report
               text/plain
               message/delivery-status
               text/plain
               text/plain
               message/rfc822
               text/plain

          ‘walk’ iterates over the subparts of any part where *note
          is_multipart(): 37ae. returns ‘True’, even though
          ‘msg.get_content_maintype() == 'multipart'’ may return
          ‘False’.  We can see this in our example by making use of the
          ‘_structure’ debug helper function:

               >>> for part in msg.walk():
               ...     print(part.get_content_maintype() == 'multipart',
               ...           part.is_multipart())
               True True
               False False
               False True
               False False
               False False
               False True
               False False
               >>> _structure(msg)
               multipart/report
                   text/plain
                   message/delivery-status
                       text/plain
                       text/plain
                   message/rfc822
                       text/plain

          Here the ‘message’ parts are not ‘multiparts’, but they do
          contain subparts.  ‘is_multipart()’ returns ‘True’ and ‘walk’
          descends into the subparts.

     ‘Message’ objects can also optionally contain two instance
     attributes, which can be used when generating the plain text of a
     MIME message.

      -- Attribute: preamble

          The format of a MIME document allows for some text between the
          blank line following the headers, and the first multipart
          boundary string.  Normally, this text is never visible in a
          MIME-aware mail reader because it falls outside the standard
          MIME armor.  However, when viewing the raw text of the
          message, or when viewing the message in a non-MIME aware
          reader, this text can become visible.

          The 'preamble' attribute contains this leading extra-armor
          text for MIME documents.  When the *note Parser: 11e1.
          discovers some text after the headers but before the first
          boundary string, it assigns this text to the message’s
          'preamble' attribute.  When the *note Generator: 1213. is
          writing out the plain text representation of a MIME message,
          and it finds the message has a 'preamble' attribute, it will
          write this text in the area between the headers and the first
          boundary.  See *note email.parser: 4e. and *note
          email.generator: 40. for details.

          Note that if the message object has no preamble, the
          'preamble' attribute will be ‘None’.

      -- Attribute: epilogue

          The 'epilogue' attribute acts the same way as the 'preamble'
          attribute, except that it contains text that appears between
          the last boundary and the end of the message.

          You do not need to set the epilogue to the empty string in
          order for the *note Generator: 1213. to print a newline at the
          end of the file.

      -- Attribute: defects

          The 'defects' attribute contains a list of all the problems
          found when parsing this message.  See *note email.errors: 3f.
          for a detailed description of the possible parsing defects.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5322.html

   (2) https://datatracker.ietf.org/doc/html/rfc2822.html

   (3) https://datatracker.ietf.org/doc/html/rfc2231.html

   (4) https://datatracker.ietf.org/doc/html/rfc2231.html

   (5) https://datatracker.ietf.org/doc/html/rfc2045.html

   (6) https://datatracker.ietf.org/doc/html/rfc2045.html

   (7) https://datatracker.ietf.org/doc/html/rfc2045.html

   (8) https://datatracker.ietf.org/doc/html/rfc2231.html

   (9) https://datatracker.ietf.org/doc/html/rfc2231.html

   (10) https://datatracker.ietf.org/doc/html/rfc2045.html

   (11) https://datatracker.ietf.org/doc/html/rfc2231.html

   (12) https://datatracker.ietf.org/doc/html/rfc2183.html


File: python.info,  Node: email mime Creating email and MIME objects from scratch,  Next: email header Internationalized headers,  Prev: email message Message Representing an email message using the compat32 API,  Up: email — An email and MIME handling package

5.20.1.14 ‘email.mime’: Creating email and MIME objects from scratch
....................................................................

'Source code:' Lib/email/mime/(1)

__________________________________________________________________

This module is part of the legacy (‘Compat32’) email API. Its
functionality is partially replaced by the *note contentmanager: 3d. in
the new API, but in certain applications these classes may still be
useful, even in non-legacy code.

Ordinarily, you get a message object structure by passing a file or some
text to a parser, which parses the text and returns the root message
object.  However you can also build a complete message structure from
scratch, or even individual *note Message: 27c. objects by hand.  In
fact, you can also take an existing structure and add new ‘Message’
objects, move them around, etc.  This makes a very convenient interface
for slicing-and-dicing MIME messages.

You can create a new object structure by creating *note Message: 27c.
instances, adding attachments and all the appropriate headers manually.
For MIME messages though, the *note email: 3b. package provides some
convenient subclasses to make things easier.

Here are the classes:

 -- Class: email.mime.base.MIMEBase (_maintype, _subtype, *,
          policy=compat32, **_params)

     Module: *note email.mime.base: 48.

     This is the base class for all the MIME-specific subclasses of
     *note Message: 27c.  Ordinarily you won’t create instances
     specifically of ‘MIMEBase’, although you could.  ‘MIMEBase’ is
     provided primarily as a convenient base class for more specific
     MIME-aware subclasses.

     '_maintype' is the ‘Content-Type’ major type (e.g.  ‘text’ or
     ‘image’), and '_subtype' is the ‘Content-Type’ minor type (e.g.
     ‘plain’ or ‘gif’).  '_params' is a parameter key/value dictionary
     and is passed directly to *note Message.add_header: 3858.

     If 'policy' is specified, (defaults to the *note compat32: 10f8.
     policy) it will be passed to *note Message: 27c.

     The ‘MIMEBase’ class always adds a ‘Content-Type’ header (based on
     '_maintype', '_subtype', and '_params'), and a ‘MIME-Version’
     header (always set to ‘1.0’).

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.nonmultipart.MIMENonMultipart

     Module: *note email.mime.nonmultipart: 4c.

     A subclass of *note MIMEBase: 3870, this is an intermediate base
     class for MIME messages that are not ‘multipart’.  The primary
     purpose of this class is to prevent the use of the *note attach():
     37bb. method, which only makes sense for ‘multipart’ messages.  If
     ‘attach()’ is called, a *note MultipartConversionError: 3802.
     exception is raised.

 -- Class: email.mime.multipart.MIMEMultipart (_subtype='mixed',
          boundary=None, _subparts=None, *, policy=compat32, **_params)

     Module: *note email.mime.multipart: 4b.

     A subclass of *note MIMEBase: 3870, this is an intermediate base
     class for MIME messages that are ‘multipart’.  Optional '_subtype'
     defaults to ‘mixed’, but can be used to specify the subtype of the
     message.  A ‘Content-Type’ header of ‘multipart/_subtype’ will be
     added to the message object.  A ‘MIME-Version’ header will also be
     added.

     Optional 'boundary' is the multipart boundary string.  When ‘None’
     (the default), the boundary is calculated when needed (for example,
     when the message is serialized).

     '_subparts' is a sequence of initial subparts for the payload.  It
     must be possible to convert this sequence to a list.  You can
     always attach new subparts to the message by using the *note
     Message.attach: 37bb. method.

     Optional 'policy' argument defaults to *note compat32: 10f8.

     Additional parameters for the ‘Content-Type’ header are taken from
     the keyword arguments, or passed into the '_params' argument, which
     is a keyword dictionary.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.application.MIMEApplication (_data,
          _subtype='octet-stream',
          _encoder=email.encoders.encode_base64, *, policy=compat32,
          **_params)

     Module: *note email.mime.application: 46.

     A subclass of *note MIMENonMultipart: 3803, the ‘MIMEApplication’
     class is used to represent MIME message objects of major type
     ‘application’.  '_data' contains the bytes for the raw application
     data.  Optional '_subtype' specifies the MIME subtype and defaults
     to ‘octet-stream’.

     Optional '_encoder' is a callable (i.e.  function) which will
     perform the actual encoding of the data for transport.  This
     callable takes one argument, which is the ‘MIMEApplication’
     instance.  It should use *note get_payload(): 1212. and *note
     set_payload(): 384c. to change the payload to encoded form.  It
     should also add any ‘Content-Transfer-Encoding’ or other headers to
     the message object as necessary.  The default encoding is base64.
     See the *note email.encoders: 3e. module for a list of the built-in
     encoders.

     Optional 'policy' argument defaults to *note compat32: 10f8.

     '_params' are passed straight through to the base class
     constructor.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.audio.MIMEAudio (_audiodata, _subtype=None,
          _encoder=email.encoders.encode_base64, *, policy=compat32,
          **_params)

     Module: *note email.mime.audio: 47.

     A subclass of *note MIMENonMultipart: 3803, the ‘MIMEAudio’ class
     is used to create MIME message objects of major type ‘audio’.
     '_audiodata' contains the bytes for the raw audio data.  If this
     data can be decoded as au, wav, aiff, or aifc, then the subtype
     will be automatically included in the ‘Content-Type’ header.
     Otherwise you can explicitly specify the audio subtype via the
     '_subtype' argument.  If the minor type could not be guessed and
     '_subtype' was not given, then *note TypeError: 2c3. is raised.

     Optional '_encoder' is a callable (i.e.  function) which will
     perform the actual encoding of the audio data for transport.  This
     callable takes one argument, which is the ‘MIMEAudio’ instance.  It
     should use *note get_payload(): 1212. and *note set_payload():
     384c. to change the payload to encoded form.  It should also add
     any ‘Content-Transfer-Encoding’ or other headers to the message
     object as necessary.  The default encoding is base64.  See the
     *note email.encoders: 3e. module for a list of the built-in
     encoders.

     Optional 'policy' argument defaults to *note compat32: 10f8.

     '_params' are passed straight through to the base class
     constructor.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.image.MIMEImage (_imagedata, _subtype=None,
          _encoder=email.encoders.encode_base64, *, policy=compat32,
          **_params)

     Module: *note email.mime.image: 49.

     A subclass of *note MIMENonMultipart: 3803, the ‘MIMEImage’ class
     is used to create MIME message objects of major type ‘image’.
     '_imagedata' contains the bytes for the raw image data.  If this
     data type can be detected (jpeg, png, gif, tiff, rgb, pbm, pgm,
     ppm, rast, xbm, bmp, webp, and exr attempted), then the subtype
     will be automatically included in the ‘Content-Type’ header.
     Otherwise you can explicitly specify the image subtype via the
     '_subtype' argument.  If the minor type could not be guessed and
     '_subtype' was not given, then *note TypeError: 2c3. is raised.

     Optional '_encoder' is a callable (i.e.  function) which will
     perform the actual encoding of the image data for transport.  This
     callable takes one argument, which is the ‘MIMEImage’ instance.  It
     should use *note get_payload(): 1212. and *note set_payload():
     384c. to change the payload to encoded form.  It should also add
     any ‘Content-Transfer-Encoding’ or other headers to the message
     object as necessary.  The default encoding is base64.  See the
     *note email.encoders: 3e. module for a list of the built-in
     encoders.

     Optional 'policy' argument defaults to *note compat32: 10f8.

     '_params' are passed straight through to the *note MIMEBase: 3870.
     constructor.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.message.MIMEMessage (_msg, _subtype='rfc822', *,
          policy=compat32)

     Module: *note email.mime.message: 4a.

     A subclass of *note MIMENonMultipart: 3803, the ‘MIMEMessage’ class
     is used to create MIME objects of main type ‘message’.  '_msg' is
     used as the payload, and must be an instance of class *note
     Message: 27c. (or a subclass thereof), otherwise a *note TypeError:
     2c3. is raised.

     Optional '_subtype' sets the subtype of the message; it defaults to
     ‘rfc822’.

     Optional 'policy' argument defaults to *note compat32: 10f8.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

 -- Class: email.mime.text.MIMEText (_text, _subtype='plain',
          _charset=None, *, policy=compat32)

     Module: *note email.mime.text: 4d.

     A subclass of *note MIMENonMultipart: 3803, the ‘MIMEText’ class is
     used to create MIME objects of major type ‘text’.  '_text' is the
     string for the payload.  '_subtype' is the minor type and defaults
     to ‘plain’.  '_charset' is the character set of the text and is
     passed as an argument to the ‘MIMENonMultipart’ constructor; it
     defaults to ‘us-ascii’ if the string contains only ‘ascii’ code
     points, and ‘utf-8’ otherwise.  The '_charset' parameter accepts
     either a string or a *note Charset: e2c. instance.

     Unless the '_charset' argument is explicitly set to ‘None’, the
     MIMEText object created will have both a ‘Content-Type’ header with
     a ‘charset’ parameter, and a ‘Content-Transfer-Encoding’ header.
     This means that a subsequent ‘set_payload’ call will not result in
     an encoded payload, even if a charset is passed in the
     ‘set_payload’ command.  You can “reset” this behavior by deleting
     the ‘Content-Transfer-Encoding’ header, after which a ‘set_payload’
     call will automatically encode the new payload (and add a new
     ‘Content-Transfer-Encoding’ header).

     Optional 'policy' argument defaults to *note compat32: 10f8.

     Changed in version 3.5: '_charset' also accepts *note Charset: e2c.
     instances.

     Changed in version 3.6: Added 'policy' keyword-only parameter.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/mime/


File: python.info,  Node: email header Internationalized headers,  Next: email charset Representing character sets,  Prev: email mime Creating email and MIME objects from scratch,  Up: email — An email and MIME handling package

5.20.1.15 ‘email.header’: Internationalized headers
...................................................

'Source code:' Lib/email/header.py(1)

__________________________________________________________________

This module is part of the legacy (‘Compat32’) email API. In the current
API encoding and decoding of headers is handled transparently by the
dictionary-like API of the *note EmailMessage: 27b. class.  In addition
to uses in legacy code, this module can be useful in applications that
need to completely control the character sets used when encoding
headers.

The remaining text in this section is the original documentation of the
module.

RFC 2822(2) is the base standard that describes the format of email
messages.  It derives from the older RFC 822(3) standard which came into
widespread use at a time when most email was composed of ASCII
characters only.  RFC 2822(4) is a specification written assuming email
contains only 7-bit ASCII characters.

Of course, as email has been deployed worldwide, it has become
internationalized, such that language specific character sets can now be
used in email messages.  The base standard still requires email messages
to be transferred using only 7-bit ASCII characters, so a slew of RFCs
have been written describing how to encode email containing non-ASCII
characters into RFC 2822(5)-compliant format.  These RFCs include RFC
2045(6), RFC 2046(7), RFC 2047(8), and RFC 2231(9).  The *note email:
3b. package supports these standards in its ‘email.header’ and *note
email.charset: 3c. modules.

If you want to include non-ASCII characters in your email headers, say
in the ‘Subject’ or ‘To’ fields, you should use the *note Header: 1a04.
class and assign the field in the *note Message: 27c. object to an
instance of ‘Header’ instead of using a string for the header value.
Import the ‘Header’ class from the ‘email.header’ module.  For example:

     >>> from email.message import Message
     >>> from email.header import Header
     >>> msg = Message()
     >>> h = Header('p\xf6stal', 'iso-8859-1')
     >>> msg['Subject'] = h
     >>> msg.as_string()
     'Subject: =?iso-8859-1?q?p=F6stal?=\n\n'

Notice here how we wanted the ‘Subject’ field to contain a non-ASCII
character?  We did this by creating a *note Header: 1a04. instance and
passing in the character set that the byte string was encoded in.  When
the subsequent *note Message: 27c. instance was flattened, the ‘Subject’
field was properly RFC 2047(10) encoded.  MIME-aware mail readers would
show this header using the embedded ISO-8859-1 character.

Here is the *note Header: 1a04. class description:

 -- Class: email.header.Header (s=None, charset=None, maxlinelen=None,
          header_name=None, continuation_ws=' ', errors='strict')

     Create a MIME-compliant header that can contain strings in
     different character sets.

     Optional 's' is the initial header value.  If ‘None’ (the default),
     the initial header value is not set.  You can later append to the
     header with *note append(): 3878. method calls.  's' may be an
     instance of *note bytes: 1c2. or *note str: 44f, but see the
     ‘append()’ documentation for semantics.

     Optional 'charset' serves two purposes: it has the same meaning as
     the 'charset' argument to the *note append(): 3878. method.  It
     also sets the default character set for all subsequent ‘append()’
     calls that omit the 'charset' argument.  If 'charset' is not
     provided in the constructor (the default), the ‘us-ascii’ character
     set is used both as 's'’s initial charset and as the default for
     subsequent ‘append()’ calls.

     The maximum line length can be specified explicitly via
     'maxlinelen'.  For splitting the first line to a shorter value (to
     account for the field header which isn’t included in 's', e.g.
     ‘Subject’) pass in the name of the field in 'header_name'.  The
     default 'maxlinelen' is 78, and the default value for 'header_name'
     is ‘None’, meaning it is not taken into account for the first line
     of a long, split header.

     Optional 'continuation_ws' must be RFC 2822(11)-compliant folding
     whitespace, and is usually either a space or a hard tab character.
     This character will be prepended to continuation lines.
     'continuation_ws' defaults to a single space character.

     Optional 'errors' is passed straight through to the *note append():
     3878. method.

      -- Method: append (s, charset=None, errors='strict')

          Append the string 's' to the MIME header.

          Optional 'charset', if given, should be a *note Charset: e2c.
          instance (see *note email.charset: 3c.) or the name of a
          character set, which will be converted to a ‘Charset’
          instance.  A value of ‘None’ (the default) means that the
          'charset' given in the constructor is used.

          's' may be an instance of *note bytes: 1c2. or *note str: 44f.
          If it is an instance of ‘bytes’, then 'charset' is the
          encoding of that byte string, and a *note UnicodeError: 12eb.
          will be raised if the string cannot be decoded with that
          character set.

          If 's' is an instance of *note str: 44f, then 'charset' is a
          hint specifying the character set of the characters in the
          string.

          In either case, when producing an RFC 2822(12)-compliant
          header using RFC 2047(13) rules, the string will be encoded
          using the output codec of the charset.  If the string cannot
          be encoded using the output codec, a UnicodeError will be
          raised.

          Optional 'errors' is passed as the errors argument to the
          decode call if 's' is a byte string.

      -- Method: encode (splitchars=';, \t', maxlinelen=None,
               linesep='\n')

          Encode a message header into an RFC-compliant format, possibly
          wrapping long lines and encapsulating non-ASCII parts in
          base64 or quoted-printable encodings.

          Optional 'splitchars' is a string containing characters which
          should be given extra weight by the splitting algorithm during
          normal header wrapping.  This is in very rough support of RFC
          2822(14)'s ‘higher level syntactic breaks’: split points
          preceded by a splitchar are preferred during line splitting,
          with the characters preferred in the order in which they
          appear in the string.  Space and tab may be included in the
          string to indicate whether preference should be given to one
          over the other as a split point when other split chars do not
          appear in the line being split.  Splitchars does not affect
          RFC 2047(15) encoded lines.

          'maxlinelen', if given, overrides the instance’s value for the
          maximum line length.

          'linesep' specifies the characters used to separate the lines
          of the folded header.  It defaults to the most useful value
          for Python application code (‘\n’), but ‘\r\n’ can be
          specified in order to produce headers with RFC-compliant line
          separators.

          Changed in version 3.2: Added the 'linesep' argument.

     The ‘Header’ class also provides a number of methods to support
     standard operators and built-in functions.

      -- Method: __str__ ()

          Returns an approximation of the ‘Header’ as a string, using an
          unlimited line length.  All pieces are converted to unicode
          using the specified encoding and joined together
          appropriately.  Any pieces with a charset of ‘'unknown-8bit'’
          are decoded as ASCII using the ‘'replace'’ error handler.

          Changed in version 3.2: Added handling for the
          ‘'unknown-8bit'’ charset.

      -- Method: __eq__ (other)

          This method allows you to compare two ‘Header’ instances for
          equality.

      -- Method: __ne__ (other)

          This method allows you to compare two ‘Header’ instances for
          inequality.

The ‘email.header’ module also provides the following convenient
functions.

 -- Function: email.header.decode_header (header)

     Decode a message header value without converting the character set.
     The header value is in 'header'.

     For historical reasons, this function may return either:

       1. A list of pairs containing each of the decoded parts of the
          header, ‘(decoded_bytes, charset)’, where 'decoded_bytes' is
          always an instance of *note bytes: 1c2, and 'charset' is
          either:

                  - A lower case string containing the name of the
                    character set specified.

                  - ‘None’ for non-encoded parts of the header.

       2. A list of length 1 containing a pair ‘(string, None)’, where
          'string' is always an instance of *note str: 44f.

     An *note email.errors.HeaderParseError: 37aa. may be raised when
     certain decoding errors occur (e.g.  a base64 decoding exception).

     Here are examples:

          >>> from email.header import decode_header
          >>> decode_header('=?iso-8859-1?q?p=F6stal?=')
          [(b'p\xf6stal', 'iso-8859-1')]
          >>> decode_header('unencoded_string')
          [('unencoded_string', None)]
          >>> decode_header('bar =?utf-8?B?ZsOzbw==?=')
          [(b'bar ', None), (b'f\xc3\xb3o', 'utf-8')]

          Note: This function exists for backwards compatibility only.
          For new code, we recommend using *note
          email.headerregistry.HeaderRegistry: 3814.

 -- Function: email.header.make_header (decoded_seq, maxlinelen=None,
          header_name=None, continuation_ws=' ')

     Create a *note Header: 1a04. instance from a sequence of pairs as
     returned by *note decode_header(): 10fc.

     *note decode_header(): 10fc. takes a header value string and
     returns a sequence of pairs of the format ‘(decoded_string,
     charset)’ where 'charset' is the name of the character set.

     This function takes one of those sequence of pairs and returns a
     *note Header: 1a04. instance.  Optional 'maxlinelen',
     'header_name', and 'continuation_ws' are as in the ‘Header’
     constructor.

          Note: This function exists for backwards compatibility only,
          and is not recommended for use in new code.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/header.py

   (2) https://datatracker.ietf.org/doc/html/rfc2822.html

   (3) https://datatracker.ietf.org/doc/html/rfc822.html

   (4) https://datatracker.ietf.org/doc/html/rfc2822.html

   (5) https://datatracker.ietf.org/doc/html/rfc2822.html

   (6) https://datatracker.ietf.org/doc/html/rfc2045.html

   (7) https://datatracker.ietf.org/doc/html/rfc2046.html

   (8) https://datatracker.ietf.org/doc/html/rfc2047.html

   (9) https://datatracker.ietf.org/doc/html/rfc2231.html

   (10) https://datatracker.ietf.org/doc/html/rfc2047.html

   (11) https://datatracker.ietf.org/doc/html/rfc2822.html

   (12) https://datatracker.ietf.org/doc/html/rfc2822.html

   (13) https://datatracker.ietf.org/doc/html/rfc2047.html

   (14) https://datatracker.ietf.org/doc/html/rfc2822.html

   (15) https://datatracker.ietf.org/doc/html/rfc2047.html


File: python.info,  Node: email charset Representing character sets,  Next: email encoders Encoders,  Prev: email header Internationalized headers,  Up: email — An email and MIME handling package

5.20.1.16 ‘email.charset’: Representing character sets
......................................................

'Source code:' Lib/email/charset.py(1)

__________________________________________________________________

This module is part of the legacy (‘Compat32’) email API. In the new API
only the aliases table is used.

The remaining text in this section is the original documentation of the
module.

This module provides a class *note Charset: e2c. for representing
character sets and character set conversions in email messages, as well
as a character set registry and several convenience methods for
manipulating this registry.  Instances of ‘Charset’ are used in several
other modules within the *note email: 3b. package.

Import this class from the ‘email.charset’ module.

 -- Class: email.charset.Charset (input_charset=DEFAULT_CHARSET)

     Map character sets to their email properties.

     This class provides information about the requirements imposed on
     email for a specific character set.  It also provides convenience
     routines for converting between character sets, given the
     availability of the applicable codecs.  Given a character set, it
     will do its best to provide information on how to use that
     character set in an email message in an RFC-compliant way.

     Certain character sets must be encoded with quoted-printable or
     base64 when used in email headers or bodies.  Certain character
     sets must be converted outright, and are not allowed in email.

     Optional 'input_charset' is as described below; it is always
     coerced to lower case.  After being alias normalized it is also
     used as a lookup into the registry of character sets to find out
     the header encoding, body encoding, and output conversion codec to
     be used for the character set.  For example, if 'input_charset' is
     ‘iso-8859-1’, then headers and bodies will be encoded using
     quoted-printable and no output conversion codec is necessary.  If
     'input_charset' is ‘euc-jp’, then headers will be encoded with
     base64, bodies will not be encoded, but output text will be
     converted from the ‘euc-jp’ character set to the ‘iso-2022-jp’
     character set.

     ‘Charset’ instances have the following data attributes:

      -- Attribute: input_charset

          The initial character set specified.  Common aliases are
          converted to their 'official' email names (e.g.  ‘latin_1’ is
          converted to ‘iso-8859-1’).  Defaults to 7-bit ‘us-ascii’.

      -- Attribute: header_encoding

          If the character set must be encoded before it can be used in
          an email header, this attribute will be set to ‘charset.QP’
          (for quoted-printable), ‘charset.BASE64’ (for base64
          encoding), or ‘charset.SHORTEST’ for the shortest of QP or
          BASE64 encoding.  Otherwise, it will be ‘None’.

      -- Attribute: body_encoding

          Same as 'header_encoding', but describes the encoding for the
          mail message’s body, which indeed may be different than the
          header encoding.  ‘charset.SHORTEST’ is not allowed for
          'body_encoding'.

      -- Attribute: output_charset

          Some character sets must be converted before they can be used
          in email headers or bodies.  If the 'input_charset' is one of
          them, this attribute will contain the name of the character
          set output will be converted to.  Otherwise, it will be
          ‘None’.

      -- Attribute: input_codec

          The name of the Python codec used to convert the
          'input_charset' to Unicode.  If no conversion codec is
          necessary, this attribute will be ‘None’.

      -- Attribute: output_codec

          The name of the Python codec used to convert Unicode to the
          'output_charset'.  If no conversion codec is necessary, this
          attribute will have the same value as the 'input_codec'.

     ‘Charset’ instances also have the following methods:

      -- Method: get_body_encoding ()

          Return the content transfer encoding used for body encoding.

          This is either the string ‘quoted-printable’ or ‘base64’
          depending on the encoding used, or it is a function, in which
          case you should call the function with a single argument, the
          Message object being encoded.  The function should then set
          the ‘Content-Transfer-Encoding’ header itself to whatever is
          appropriate.

          Returns the string ‘quoted-printable’ if 'body_encoding' is
          ‘QP’, returns the string ‘base64’ if 'body_encoding' is
          ‘BASE64’, and returns the string ‘7bit’ otherwise.

      -- Method: get_output_charset ()

          Return the output character set.

          This is the 'output_charset' attribute if that is not ‘None’,
          otherwise it is 'input_charset'.

      -- Method: header_encode (string)

          Header-encode the string 'string'.

          The type of encoding (base64 or quoted-printable) will be
          based on the 'header_encoding' attribute.

      -- Method: header_encode_lines (string, maxlengths)

          Header-encode a 'string' by converting it first to bytes.

          This is similar to *note header_encode(): 3888. except that
          the string is fit into maximum line lengths as given by the
          argument 'maxlengths', which must be an iterator: each element
          returned from this iterator will provide the next maximum line
          length.

      -- Method: body_encode (string)

          Body-encode the string 'string'.

          The type of encoding (base64 or quoted-printable) will be
          based on the 'body_encoding' attribute.

     The ‘Charset’ class also provides a number of methods to support
     standard operations and built-in functions.

      -- Method: __str__ ()

          Returns 'input_charset' as a string coerced to lower case.
          ‘__repr__()’ is an alias for ‘__str__()’.

      -- Method: __eq__ (other)

          This method allows you to compare two ‘Charset’ instances for
          equality.

      -- Method: __ne__ (other)

          This method allows you to compare two ‘Charset’ instances for
          inequality.

The ‘email.charset’ module also provides the following functions for
adding new entries to the global character set, alias, and codec
registries:

 -- Function: email.charset.add_charset (charset, header_enc=None,
          body_enc=None, output_charset=None)

     Add character properties to the global registry.

     'charset' is the input character set, and must be the canonical
     name of a character set.

     Optional 'header_enc' and 'body_enc' is either ‘charset.QP’ for
     quoted-printable, ‘charset.BASE64’ for base64 encoding,
     ‘charset.SHORTEST’ for the shortest of quoted-printable or base64
     encoding, or ‘None’ for no encoding.  ‘SHORTEST’ is only valid for
     'header_enc'.  The default is ‘None’ for no encoding.

     Optional 'output_charset' is the character set that the output
     should be in.  Conversions will proceed from input charset, to
     Unicode, to the output charset when the method ‘Charset.convert()’
     is called.  The default is to output in the same character set as
     the input.

     Both 'input_charset' and 'output_charset' must have Unicode codec
     entries in the module’s character set-to-codec mapping; use *note
     add_codec(): 388f. to add codecs the module does not know about.
     See the *note codecs: 1b. module’s documentation for more
     information.

     The global character set registry is kept in the module global
     dictionary ‘CHARSETS’.

 -- Function: email.charset.add_alias (alias, canonical)

     Add a character set alias.  'alias' is the alias name, e.g.
     ‘latin-1’.  'canonical' is the character set’s canonical name, e.g.
     ‘iso-8859-1’.

     The global charset alias registry is kept in the module global
     dictionary ‘ALIASES’.

 -- Function: email.charset.add_codec (charset, codecname)

     Add a codec that map characters in the given character set to and
     from Unicode.

     'charset' is the canonical name of a character set.  'codecname' is
     the name of a Python codec, as appropriate for the second argument
     to the *note str: 44f.’s *note encode(): 8de. method.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/charset.py


File: python.info,  Node: email encoders Encoders,  Next: email utils Miscellaneous utilities,  Prev: email charset Representing character sets,  Up: email — An email and MIME handling package

5.20.1.17 ‘email.encoders’: Encoders
....................................

'Source code:' Lib/email/encoders.py(1)

__________________________________________________________________

This module is part of the legacy (‘Compat32’) email API. In the new API
the functionality is provided by the 'cte' parameter of the *note
set_content(): 1a03. method.

This module is deprecated in Python 3.  The functions provided here
should not be called explicitly since the *note MIMEText: e2b. class
sets the content type and CTE header using the '_subtype' and '_charset'
values passed during the instantiation of that class.

The remaining text in this section is the original documentation of the
module.

When creating *note Message: 27c. objects from scratch, you often need
to encode the payloads for transport through compliant mail servers.
This is especially true for ‘image/*’ and ‘text/*’ type messages
containing binary data.

The *note email: 3b. package provides some convenient encoders in its
‘encoders’ module.  These encoders are actually used by the *note
MIMEAudio: 3873. and *note MIMEImage: 3804. class constructors to
provide default encodings.  All encoder functions take exactly one
argument, the message object to encode.  They usually extract the
payload, encode it, and reset the payload to this newly encoded value.
They should also set the ‘Content-Transfer-Encoding’ header as
appropriate.

Note that these functions are not meaningful for a multipart message.
They must be applied to individual subparts instead, and will raise a
*note TypeError: 2c3. if passed a message whose type is multipart.

Here are the encoding functions provided:

 -- Function: email.encoders.encode_quopri (msg)

     Encodes the payload into quoted-printable form and sets the
     ‘Content-Transfer-Encoding’ header to ‘quoted-printable’ (2).  This
     is a good encoding to use when most of your payload is normal
     printable data, but contains a few unprintable characters.

 -- Function: email.encoders.encode_base64 (msg)

     Encodes the payload into base64 form and sets the
     ‘Content-Transfer-Encoding’ header to ‘base64’.  This is a good
     encoding to use when most of your payload is unprintable data since
     it is a more compact form than quoted-printable.  The drawback of
     base64 encoding is that it renders the text non-human readable.

 -- Function: email.encoders.encode_7or8bit (msg)

     This doesn’t actually modify the message’s payload, but it does set
     the ‘Content-Transfer-Encoding’ header to either ‘7bit’ or ‘8bit’
     as appropriate, based on the payload data.

 -- Function: email.encoders.encode_noop (msg)

     This does nothing; it doesn’t even set the
     ‘Content-Transfer-Encoding’ header.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/encoders.py

   (2) Note that encoding with *note encode_quopri(): 3894. also encodes
all tabs and space characters in the data.


File: python.info,  Node: email utils Miscellaneous utilities,  Next: email iterators Iterators,  Prev: email encoders Encoders,  Up: email — An email and MIME handling package

5.20.1.18 ‘email.utils’: Miscellaneous utilities
................................................

'Source code:' Lib/email/utils.py(1)

__________________________________________________________________

There are a couple of useful utilities provided in the ‘email.utils’
module:

 -- Function: email.utils.localtime (dt=None)

     Return local time as an aware datetime object.  If called without
     arguments, return current time.  Otherwise 'dt' argument should be
     a *note datetime: 1cc. instance, and it is converted to the local
     time zone according to the system time zone database.  If 'dt' is
     naive (that is, ‘dt.tzinfo’ is ‘None’), it is assumed to be in
     local time.  The 'isdst' parameter is ignored.

     Added in version 3.3.

     Deprecated since version 3.12, will be removed in version 3.14: The
     'isdst' parameter.

 -- Function: email.utils.make_msgid (idstring=None, domain=None)

     Returns a string suitable for an RFC 2822(2)-compliant ‘Message-ID’
     header.  Optional 'idstring' if given, is a string used to
     strengthen the uniqueness of the message id.  Optional 'domain' if
     given provides the portion of the msgid after the ‘@’.  The default
     is the local hostname.  It is not normally necessary to override
     this default, but may be useful certain cases, such as a
     constructing distributed system that uses a consistent domain name
     across multiple hosts.

     Changed in version 3.2: Added the 'domain' keyword.

The remaining functions are part of the legacy (‘Compat32’) email API.
There is no need to directly use these with the new API, since the
parsing and formatting they provide is done automatically by the header
parsing machinery of the new API.

 -- Function: email.utils.quote (str)

     Return a new string with backslashes in 'str' replaced by two
     backslashes, and double quotes replaced by backslash-double quote.

 -- Function: email.utils.unquote (str)

     Return a new string which is an 'unquoted' version of 'str'.  If
     'str' ends and begins with double quotes, they are stripped off.
     Likewise if 'str' ends and begins with angle brackets, they are
     stripped off.

 -- Function: email.utils.parseaddr (address, *, strict=True)

     Parse address – which should be the value of some
     address-containing field such as ‘To’ or ‘Cc’ – into its
     constituent 'realname' and 'email address' parts.  Returns a tuple
     of that information, unless the parse fails, in which case a
     2-tuple of ‘('', '')’ is returned.

     If 'strict' is true, use a strict parser which rejects malformed
     inputs.

     Changed in version 3.13: Add 'strict' optional parameter and reject
     malformed inputs by default.

 -- Function: email.utils.formataddr (pair, charset='utf-8')

     The inverse of *note parseaddr(): 1e2, this takes a 2-tuple of the
     form ‘(realname, email_address)’ and returns the string value
     suitable for a ‘To’ or ‘Cc’ header.  If the first element of 'pair'
     is false, then the second element is returned unmodified.

     Optional 'charset' is the character set that will be used in the
     RFC 2047(3) encoding of the ‘realname’ if the ‘realname’ contains
     non-ASCII characters.  Can be an instance of *note str: 44f. or a
     *note Charset: e2c.  Defaults to ‘utf-8’.

     Changed in version 3.3: Added the 'charset' option.

 -- Function: email.utils.getaddresses (fieldvalues, *, strict=True)

     This method returns a list of 2-tuples of the form returned by
     ‘parseaddr()’.  'fieldvalues' is a sequence of header field values
     as might be returned by *note Message.get_all: 3852.

     If 'strict' is true, use a strict parser which rejects malformed
     inputs.

     Here’s a simple example that gets all the recipients of a message:

          from email.utils import getaddresses

          tos = msg.get_all('to', [])
          ccs = msg.get_all('cc', [])
          resent_tos = msg.get_all('resent-to', [])
          resent_ccs = msg.get_all('resent-cc', [])
          all_recipients = getaddresses(tos + ccs + resent_tos + resent_ccs)

     Changed in version 3.13: Add 'strict' optional parameter and reject
     malformed inputs by default.

 -- Function: email.utils.parsedate (date)

     Attempts to parse a date according to the rules in RFC 2822(4).
     however, some mailers don’t follow that format as specified, so
     ‘parsedate()’ tries to guess correctly in such cases.  'date' is a
     string containing an RFC 2822(5) date, such as ‘"Mon, 20 Nov 1995
     19:12:08 -0500"’.  If it succeeds in parsing the date,
     ‘parsedate()’ returns a 9-tuple that can be passed directly to
     *note time.mktime(): 122d.; otherwise ‘None’ will be returned.
     Note that indexes 6, 7, and 8 of the result tuple are not usable.

 -- Function: email.utils.parsedate_tz (date)

     Performs the same function as *note parsedate(): 389d, but returns
     either ‘None’ or a 10-tuple; the first 9 elements make up a tuple
     that can be passed directly to *note time.mktime(): 122d, and the
     tenth is the offset of the date’s timezone from UTC (which is the
     official term for Greenwich Mean Time) (6).  If the input string
     has no timezone, the last element of the tuple returned is ‘0’,
     which represents UTC. Note that indexes 6, 7, and 8 of the result
     tuple are not usable.

 -- Function: email.utils.parsedate_to_datetime (date)

     The inverse of *note format_datetime(): 1101.  Performs the same
     function as *note parsedate(): 389d, but on success returns a *note
     datetime: 1cc.; otherwise ‘ValueError’ is raised if 'date' contains
     an invalid value such as an hour greater than 23 or a timezone
     offset not between -24 and 24 hours.  If the input date has a
     timezone of ‘-0000’, the ‘datetime’ will be a naive ‘datetime’, and
     if the date is conforming to the RFCs it will represent a time in
     UTC but with no indication of the actual source timezone of the
     message the date comes from.  If the input date has any other valid
     timezone offset, the ‘datetime’ will be an aware ‘datetime’ with
     the corresponding a *note timezone: 1103. *note tzinfo: 5e1.

     Added in version 3.3.

 -- Function: email.utils.mktime_tz (tuple)

     Turn a 10-tuple as returned by *note parsedate_tz(): 19c7. into a
     UTC timestamp (seconds since the Epoch).  If the timezone item in
     the tuple is ‘None’, assume local time.

 -- Function: email.utils.formatdate (timeval=None, localtime=False,
          usegmt=False)

     Returns a date string as per RFC 2822(7), e.g.:

          Fri, 09 Nov 2001 01:08:47 -0000

     Optional 'timeval' if given is a floating-point time value as
     accepted by *note time.gmtime(): 1205. and *note time.localtime():
     1548, otherwise the current time is used.

     Optional 'localtime' is a flag that when ‘True’, interprets
     'timeval', and returns a date relative to the local timezone
     instead of UTC, properly taking daylight savings time into account.
     The default is ‘False’ meaning UTC is used.

     Optional 'usegmt' is a flag that when ‘True’, outputs a date string
     with the timezone as an ascii string ‘GMT’, rather than a numeric
     ‘-0000’.  This is needed for some protocols (such as HTTP). This
     only applies when 'localtime' is ‘False’.  The default is ‘False’.

 -- Function: email.utils.format_datetime (dt, usegmt=False)

     Like ‘formatdate’, but the input is a *note datetime: 30. instance.
     If it is a naive datetime, it is assumed to be “UTC with no
     information about the source timezone”, and the conventional
     ‘-0000’ is used for the timezone.  If it is an aware ‘datetime’,
     then the numeric timezone offset is used.  If it is an aware
     timezone with offset zero, then 'usegmt' may be set to ‘True’, in
     which case the string ‘GMT’ is used instead of the numeric timezone
     offset.  This provides a way to generate standards conformant HTTP
     date headers.

     Added in version 3.3.

 -- Function: email.utils.decode_rfc2231 (s)

     Decode the string 's' according to RFC 2231(8).

 -- Function: email.utils.encode_rfc2231 (s, charset=None,
          language=None)

     Encode the string 's' according to RFC 2231(9).  Optional 'charset'
     and 'language', if given is the character set name and language
     name to use.  If neither is given, 's' is returned as-is.  If
     'charset' is given but 'language' is not, the string is encoded
     using the empty string for 'language'.

 -- Function: email.utils.collapse_rfc2231_value (value,
          errors='replace', fallback_charset='us-ascii')

     When a header parameter is encoded in RFC 2231(10) format, *note
     Message.get_param: 3860. may return a 3-tuple containing the
     character set, language, and value.  ‘collapse_rfc2231_value()’
     turns this into a unicode string.  Optional 'errors' is passed to
     the 'errors' argument of *note str: 44f.’s *note encode(): 8de.
     method; it defaults to ‘'replace'’.  Optional 'fallback_charset'
     specifies the character set to use if the one in the RFC 2231(11)
     header is not known by Python; it defaults to ‘'us-ascii'’.

     For convenience, if the 'value' passed to
     ‘collapse_rfc2231_value()’ is not a tuple, it should be a string
     and it is returned unquoted.

 -- Function: email.utils.decode_params (params)

     Decode parameters list according to RFC 2231(12).  'params' is a
     sequence of 2-tuples containing elements of the form
     ‘(content-type, string-value)’.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/email/utils.py

   (2) https://datatracker.ietf.org/doc/html/rfc2822.html

   (3) https://datatracker.ietf.org/doc/html/rfc2047.html

   (4) https://datatracker.ietf.org/doc/html/rfc2822.html

   (5) https://datatracker.ietf.org/doc/html/rfc2822.html

   (6) Note that the sign of the timezone offset is the opposite of the
sign of the ‘time.timezone’ variable for the same timezone; the latter
variable follows the POSIX standard while this module follows RFC 2822
(https://datatracker.ietf.org/doc/html/rfc2822.html).

   (7) https://datatracker.ietf.org/doc/html/rfc2822.html

   (8) https://datatracker.ietf.org/doc/html/rfc2231.html

   (9) https://datatracker.ietf.org/doc/html/rfc2231.html

   (10) https://datatracker.ietf.org/doc/html/rfc2231.html

   (11) https://datatracker.ietf.org/doc/html/rfc2231.html

   (12) https://datatracker.ietf.org/doc/html/rfc2231.html


File: python.info,  Node: email iterators Iterators,  Prev: email utils Miscellaneous utilities,  Up: email — An email and MIME handling package

5.20.1.19 ‘email.iterators’: Iterators
......................................

'Source code:' Lib/email/iterators.py(1)

__________________________________________________________________

Iterating over a message object tree is fairly easy with the *note
Message.walk: 3869. method.  The ‘email.iterators’ module provides some
useful higher level iterations over message object trees.

 -- Function: email.iterators.body_line_iterator (msg, decode=False)

     This iterates over all the payloads in all the subparts of 'msg',
     returning the string payloads line-by-line.  It skips over all the
     subpart headers, and it skips over any subpart with a payload that
     isn’t a Python string.  This is somewhat equivalent to reading the
     flat text representation of the message from a file using *note
     readline(): 1e5e, skipping over all the intervening headers.

     Optional 'decode' is passed through to *note Message.get_payload:
     1212.

 -- Function: email.iterators.typed_subpart_iterator (msg,
          maintype='text', subtype=None)

     This iterates over all the subparts of 'msg', returning only those
     subparts that match the MIME type specified by 'maintype' and
     'subtype'.

     Note that 'subtype' is optional; if omitted, then subpart MIME type
     matching is done only with the main type.  'maintype' is optional
     too; it defaults to ‘text’.

     Thus, by default ‘typed_subpart_iterator()’ returns each subpart
     that has a MIME type of ‘text/*’.

The following function has been added as a useful debugging tool.  It
should 'not' be considered part of the supported public interface for
the package.

 -- Function: email.iterators._structure (msg, fp=None, level=0,
          include_default=False)

     Prints an indented representation of the content types of the
     message object structure.  For example:

          >>> msg = email.message_from_file(somefile)
          >>> _structure(msg)
          multipart/mixed
              text/plain
              text/plain
              multipart/digest
                  message/rfc822
                      text/plain
                  message/rfc822
                      text/plain
                  message/rfc822
                      text/plain
                  message/rfc822
                      text/plain
                  message/rfc822
                      text/plain
              text/plain

     Optional 'fp' is a file-like object to print the output to.  It
     must be suitable for Python’s *note print(): fae. function.
     'level' is used internally.  'include_default', if true, prints the
     default type as well.

See also
........

Module *note smtplib: ca.

     SMTP (Simple Mail Transport Protocol) client

Module *note poplib: ac.

     POP (Post Office Protocol) client

Module *note imaplib: 74.

     IMAP (Internet Message Access Protocol) client

Module *note mailbox: 8b.

     Tools for creating, reading, and managing collections of messages
     on disk using a variety standard formats.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/email/iterators.py


File: python.info,  Node: json — JSON encoder and decoder,  Next: mailbox — Manipulate mailboxes in various formats,  Prev: email — An email and MIME handling package,  Up: Internet Data Handling

5.20.2 ‘json’ — JSON encoder and decoder
----------------------------------------

'Source code:' Lib/json/__init__.py(1)

__________________________________________________________________

JSON (JavaScript Object Notation)(2), specified by RFC 7159(3) (which
obsoletes RFC 4627(4)) and by ECMA-404(5), is a lightweight data
interchange format inspired by JavaScript(6) object literal syntax
(although it is not a strict subset of JavaScript (7) ).

     Note: The term “object” in the context of JSON processing in Python
     can be ambiguous.  All values in Python are objects.  In JSON, an
     object refers to any data wrapped in curly braces, similar to a
     Python dictionary.

     Warning: Be cautious when parsing JSON data from untrusted sources.
     A malicious JSON string may cause the decoder to consume
     considerable CPU and memory resources.  Limiting the size of data
     to be parsed is recommended.

This module exposes an API familiar to users of the standard library
*note marshal: 8d. and *note pickle: a6. modules.

Encoding basic Python object hierarchies:

     >>> import json
     >>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
     '["foo", {"bar": ["baz", null, 1.0, 2]}]'
     >>> print(json.dumps("\"foo\bar"))
     "\"foo\bar"
     >>> print(json.dumps('\u1234'))
     "\u1234"
     >>> print(json.dumps('\\'))
     "\\"
     >>> print(json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True))
     {"a": 0, "b": 0, "c": 0}
     >>> from io import StringIO
     >>> io = StringIO()
     >>> json.dump(['streaming API'], io)
     >>> io.getvalue()
     '["streaming API"]'

Compact encoding:

     >>> import json
     >>> json.dumps([1, 2, 3, {'4': 5, '6': 7}], separators=(',', ':'))
     '[1,2,3,{"4":5,"6":7}]'

Pretty printing:

     >>> import json
     >>> print(json.dumps({'6': 7, '4': 5}, sort_keys=True, indent=4))
     {
         "4": 5,
         "6": 7
     }

Customizing JSON object encoding:

     >>> import json
     >>> def custom_json(obj):
     ...     if isinstance(obj, complex):
     ...         return {'__complex__': True, 'real': obj.real, 'imag': obj.imag}
     ...     raise TypeError(f'Cannot serialize object of {type(obj)}')
     ...
     >>> json.dumps(1 + 2j, default=custom_json)
     '{"__complex__": true, "real": 1.0, "imag": 2.0}'

Decoding JSON:

     >>> import json
     >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
     ['foo', {'bar': ['baz', None, 1.0, 2]}]
     >>> json.loads('"\\"foo\\bar"')
     '"foo\x08ar'
     >>> from io import StringIO
     >>> io = StringIO('["streaming API"]')
     >>> json.load(io)
     ['streaming API']

Customizing JSON object decoding:

     >>> import json
     >>> def as_complex(dct):
     ...     if '__complex__' in dct:
     ...         return complex(dct['real'], dct['imag'])
     ...     return dct
     ...
     >>> json.loads('{"__complex__": true, "real": 1, "imag": 2}',
     ...     object_hook=as_complex)
     (1+2j)
     >>> import decimal
     >>> json.loads('1.1', parse_float=decimal.Decimal)
     Decimal('1.1')

Extending *note JSONEncoder: d6f.:

     >>> import json
     >>> class ComplexEncoder(json.JSONEncoder):
     ...     def default(self, obj):
     ...         if isinstance(obj, complex):
     ...             return [obj.real, obj.imag]
     ...         # Let the base class default method raise the TypeError
     ...         return super().default(obj)
     ...
     >>> json.dumps(2 + 1j, cls=ComplexEncoder)
     '[2.0, 1.0]'
     >>> ComplexEncoder().encode(2 + 1j)
     '[2.0, 1.0]'
     >>> list(ComplexEncoder().iterencode(2 + 1j))
     ['[2.0', ', 1.0', ']']

Using *note json.tool: 83. from the shell to validate and pretty-print:

     $ echo '{"json":"obj"}' | python -m json.tool
     {
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -m json.tool
     Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

See *note Command Line Interface: 38aa. for detailed documentation.

     Note: JSON is a subset of YAML(8) 1.2.  The JSON produced by this
     module’s default settings (in particular, the default 'separators'
     value) is also a subset of YAML 1.0 and 1.1.  This module can thus
     also be used as a YAML serializer.

     Note: This module’s encoders and decoders preserve input and output
     order by default.  Order is only lost if the underlying containers
     are unordered.

* Menu:

* Basic Usage::
* Encoders and Decoders::
* Exceptions: Exceptions<17>.
* Standard Compliance and Interoperability::
* Command Line Interface::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/json/__init__.py

   (2) https://json.org

   (3) https://datatracker.ietf.org/doc/html/rfc7159.html

   (4) https://datatracker.ietf.org/doc/html/rfc4627.html

   (5) 
https://ecma-international.org/publications-and-standards/standards/ecma-404/

   (6) https://en.wikipedia.org/wiki/JavaScript

   (7) As noted in the errata for RFC 7159
(https://www.rfc-editor.org/errata_search.php?rfc=7159), JSON permits
literal U+2028 (LINE SEPARATOR) and U+2029 (PARAGRAPH SEPARATOR)
characters in strings, whereas JavaScript (as of ECMAScript Edition 5.1)
does not.

   (8) https://yaml.org/


File: python.info,  Node: Basic Usage,  Next: Encoders and Decoders,  Up: json — JSON encoder and decoder

5.20.2.1 Basic Usage
....................

 -- Function: json.dump (obj, fp, *, skipkeys=False, ensure_ascii=True,
          check_circular=True, allow_nan=True, cls=None, indent=None,
          separators=None, default=None, sort_keys=False, **kw)

     Serialize 'obj' as a JSON formatted stream to 'fp' (a
     ‘.write()’-supporting *note file-like object: 15f4.) using this
     *note Python-to-JSON conversion table: 38ac.

          Note: Unlike *note pickle: a6. and *note marshal: 8d, JSON is
          not a framed protocol, so trying to serialize multiple objects
          with repeated calls to ‘dump()’ using the same 'fp' will
          result in an invalid JSON file.


     Parameters:

        * ‘obj’ (*note object: a9b.) – The Python object to be
          serialized.

        * ‘fp’ (*note file-like object: 15f4.) – The file-like object
          'obj' will be serialized to.  The ‘json’ module always
          produces *note str: 44f. objects, not *note bytes: 1c2.
          objects, therefore ‘fp.write()’ must support ‘str’ input.

        * ‘skipkeys’ (*note bool: 46b.) – If ‘True’, keys that are not
          of a basic type (*note str: 44f, *note int: 257, *note float:
          2f7, ‘bool’, ‘None’) will be skipped instead of raising a
          *note TypeError: 2c3.  Default ‘False’.

        * ‘ensure_ascii’ (*note bool: 46b.) – If ‘True’ (the default),
          the output is guaranteed to have all incoming non-ASCII and
          non-printable characters escaped.  If ‘False’, all characters
          will be outputted as-is, except for the characters that must
          be escaped: quotation mark, reverse solidus, and the control
          characters U+0000 through U+001F.

        * ‘check_circular’ (*note bool: 46b.) – If ‘False’, the circular
          reference check for container types is skipped and a circular
          reference will result in a *note RecursionError: d96. (or
          worse).  Default ‘True’.

        * ‘allow_nan’ (*note bool: 46b.) – If ‘False’, serialization of
          out-of-range *note float: 2f7. values (‘nan’, ‘inf’, ‘-inf’)
          will result in a *note ValueError: 202, in strict compliance
          with the JSON specification.  If ‘True’ (the default), their
          JavaScript equivalents (‘NaN’, ‘Infinity’, ‘-Infinity’) are
          used.

        * ‘cls’ (a *note JSONEncoder: d6f. subclass) – If set, a custom
          JSON encoder with the *note default(): 38ad. method
          overridden, for serializing into custom datatypes.  If ‘None’
          (the default), ‘JSONEncoder’ is used.

        * ‘indent’ (*note int: 257.‘ | ’*note str: 44f.‘ | ’‘None’) – If
          a positive integer or string, JSON array elements and object
          members will be pretty-printed with that indent level.  A
          positive integer indents that many spaces per level; a string
          (such as ‘"\t"’) is used to indent each level.  If zero,
          negative, or ‘""’ (the empty string), only newlines are
          inserted.  If ‘None’ (the default), the most compact
          representation is used.

        * ‘separators’ (*note tuple: 373.‘ | ’‘None’) – A two-tuple:
          ‘(item_separator, key_separator)’.  If ‘None’ (the default),
          'separators' defaults to ‘(', ', ': ')’ if 'indent' is ‘None’,
          and ‘(',', ': ')’ otherwise.  For the most compact JSON,
          specify ‘(',', ':')’ to eliminate whitespace.

        * ‘default’ (*note callable: 2acb. | None) – A function that is
          called for objects that can’t otherwise be serialized.  It
          should return a JSON encodable version of the object or raise
          a *note TypeError: 2c3.  If ‘None’ (the default), ‘TypeError’
          is raised.

        * ‘sort_keys’ (*note bool: 46b.) – If ‘True’, dictionaries will
          be outputted sorted by key.  Default ‘False’.

     Changed in version 3.2: Allow strings for 'indent' in addition to
     integers.

     Changed in version 3.4: Use ‘(',', ': ')’ as default if 'indent' is
     not ‘None’.

     Changed in version 3.6: All optional parameters are now *note
     keyword-only: 2a5.

 -- Function: json.dumps (obj, *, skipkeys=False, ensure_ascii=True,
          check_circular=True, allow_nan=True, cls=None, indent=None,
          separators=None, default=None, sort_keys=False, **kw)

     Serialize 'obj' to a JSON formatted *note str: 44f. using this
     *note conversion table: 38ac.  The arguments have the same meaning
     as in *note dump(): d6d.

          Note: Keys in key/value pairs of JSON are always of the type
          *note str: 44f.  When a dictionary is converted into JSON, all
          the keys of the dictionary are coerced to strings.  As a
          result of this, if a dictionary is converted into JSON and
          then back into a dictionary, the dictionary may not equal the
          original one.  That is, ‘loads(dumps(x)) != x’ if x has
          non-string keys.

 -- Function: json.load (fp, *, cls=None, object_hook=None,
          parse_float=None, parse_int=None, parse_constant=None,
          object_pairs_hook=None, **kw)

     Deserialize 'fp' to a Python object using the *note JSON-to-Python
     conversion table: 38ae.


     Parameters:

        * ‘fp’ (*note file-like object: 15f4.) – A ‘.read()’-supporting
          *note text file: 1e25. or *note binary file: 1e26. containing
          the JSON document to be deserialized.

        * ‘cls’ (a *note JSONDecoder: d70. subclass) – If set, a custom
          JSON decoder.  Additional keyword arguments to ‘load()’ will
          be passed to the constructor of 'cls'.  If ‘None’ (the
          default), ‘JSONDecoder’ is used.

        * ‘object_hook’ (*note callable: 2acb. | None) – If set, a
          function that is called with the result of any JSON object
          literal decoded (a *note dict: 256.).  The return value of
          this function will be used instead of the ‘dict’.  This
          feature can be used to implement custom decoders, for example
          JSON-RPC(1) class hinting.  Default ‘None’.

        * ‘object_pairs_hook’ (*note callable: 2acb. | None) – If set, a
          function that is called with the result of any JSON object
          literal decoded with an ordered list of pairs.  The return
          value of this function will be used instead of the *note dict:
          256.  This feature can be used to implement custom decoders.
          If 'object_hook' is also set, 'object_pairs_hook' takes
          priority.  Default ‘None’.

        * ‘parse_float’ (*note callable: 2acb. | None) – If set, a
          function that is called with the string of every JSON float to
          be decoded.  If ‘None’ (the default), it is equivalent to
          ‘float(num_str)’.  This can be used to parse JSON floats into
          custom datatypes, for example *note decimal.Decimal: 29d.

        * ‘parse_int’ (*note callable: 2acb. | None) – If set, a
          function that is called with the string of every JSON int to
          be decoded.  If ‘None’ (the default), it is equivalent to
          ‘int(num_str)’.  This can be used to parse JSON integers into
          custom datatypes, for example *note float: 2f7.

        * ‘parse_constant’ (*note callable: 2acb. | None) – If set, a
          function that is called with one of the following strings:
          ‘'-Infinity'’, ‘'Infinity'’, or ‘'NaN'’.  This can be used to
          raise an exception if invalid JSON numbers are encountered.
          Default ‘None’.


     Raises:

        * *note JSONDecodeError: e53. – When the data being deserialized
          is not a valid JSON document.

        * *note UnicodeDecodeError: a20. – When the data being
          deserialized does not contain UTF-8, UTF-16 or UTF-32 encoded
          data.

     Changed in version 3.1:

        * Added the optional 'object_pairs_hook' parameter.

        * 'parse_constant' doesn’t get called on ‘null’, ‘true’, ‘false’
          anymore.

     Changed in version 3.6:

        * All optional parameters are now *note keyword-only: 2a5.

        * 'fp' can now be a *note binary file: 1e26.  The input encoding
          should be UTF-8, UTF-16 or UTF-32.

     Changed in version 3.11: The default 'parse_int' of *note int():
     257. now limits the maximum length of the integer string via the
     interpreter’s *note integer string conversion length limitation:
     5f8. to help avoid denial of service attacks.

 -- Function: json.loads (s, *, cls=None, object_hook=None,
          parse_float=None, parse_int=None, parse_constant=None,
          object_pairs_hook=None, **kw)

     Identical to *note load(): cda, but instead of a file-like object,
     deserialize 's' (a *note str: 44f, *note bytes: 1c2. or *note
     bytearray: 2ea. instance containing a JSON document) to a Python
     object using this *note conversion table: 38ae.

     Changed in version 3.6: 's' can now be of type *note bytes: 1c2. or
     *note bytearray: 2ea.  The input encoding should be UTF-8, UTF-16
     or UTF-32.

     Changed in version 3.9: The keyword argument 'encoding' has been
     removed.

   ---------- Footnotes ----------

   (1) https://www.jsonrpc.org


File: python.info,  Node: Encoders and Decoders,  Next: Exceptions<17>,  Prev: Basic Usage,  Up: json — JSON encoder and decoder

5.20.2.2 Encoders and Decoders
..............................

 -- Class: json.JSONDecoder (*, object_hook=None, parse_float=None,
          parse_int=None, parse_constant=None, strict=True,
          object_pairs_hook=None)

     Simple JSON decoder.

     Performs the following translations in decoding by default:

     JSON                Python
                         
     --------------------------------------------
                         
     object              dict
                         
                         
     array               list
                         
                         
     string              str
                         
                         
     number (int)        int
                         
                         
     number (real)       float
                         
                         
     true                True
                         
                         
     false               False
                         
                         
     null                None
                         

     It also understands ‘NaN’, ‘Infinity’, and ‘-Infinity’ as their
     corresponding ‘float’ values, which is outside the JSON spec.

     'object_hook' is an optional function that will be called with the
     result of every JSON object decoded and its return value will be
     used in place of the given *note dict: 256.  This can be used to
     provide custom deserializations (e.g.  to support JSON-RPC(1) class
     hinting).

     'object_pairs_hook' is an optional function that will be called
     with the result of every JSON object decoded with an ordered list
     of pairs.  The return value of 'object_pairs_hook' will be used
     instead of the *note dict: 256.  This feature can be used to
     implement custom decoders.  If 'object_hook' is also defined, the
     'object_pairs_hook' takes priority.

     Changed in version 3.1: Added support for 'object_pairs_hook'.

     'parse_float' is an optional function that will be called with the
     string of every JSON float to be decoded.  By default, this is
     equivalent to ‘float(num_str)’.  This can be used to use another
     datatype or parser for JSON floats (e.g.  *note decimal.Decimal:
     29d.).

     'parse_int' is an optional function that will be called with the
     string of every JSON int to be decoded.  By default, this is
     equivalent to ‘int(num_str)’.  This can be used to use another
     datatype or parser for JSON integers (e.g.  *note float: 2f7.).

     'parse_constant' is an optional function that will be called with
     one of the following strings: ‘'-Infinity'’, ‘'Infinity'’, ‘'NaN'’.
     This can be used to raise an exception if invalid JSON numbers are
     encountered.

     If 'strict' is false (‘True’ is the default), then control
     characters will be allowed inside strings.  Control characters in
     this context are those with character codes in the 0–31 range,
     including ‘'\t'’ (tab), ‘'\n'’, ‘'\r'’ and ‘'\0'’.

     If the data being deserialized is not a valid JSON document, a
     *note JSONDecodeError: e53. will be raised.

     Changed in version 3.6: All parameters are now *note keyword-only:
     2a5.

      -- Method: decode (s)

          Return the Python representation of 's' (a *note str: 44f.
          instance containing a JSON document).

          *note JSONDecodeError: e53. will be raised if the given JSON
          document is not valid.

      -- Method: raw_decode (s)

          Decode a JSON document from 's' (a *note str: 44f. beginning
          with a JSON document) and return a 2-tuple of the Python
          representation and the index in 's' where the document ended.

          This can be used to decode a JSON document from a string that
          may have extraneous data at the end.

 -- Class: json.JSONEncoder (*, skipkeys=False, ensure_ascii=True,
          check_circular=True, allow_nan=True, sort_keys=False,
          indent=None, separators=None, default=None)

     Extensible JSON encoder for Python data structures.

     Supports the following objects and types by default:

     Python                                       JSON
                                                  
     -----------------------------------------------------------------
                                                  
     dict                                         object
                                                  
                                                  
     list, tuple                                  array
                                                  
                                                  
     str                                          string
                                                  
                                                  
     int, float, int- & float-derived Enums       number
                                                  
                                                  
     True                                         true
                                                  
                                                  
     False                                        false
                                                  
                                                  
     None                                         null
                                                  

     Changed in version 3.4: Added support for int- and float-derived
     Enum classes.

     To extend this to recognize other objects, subclass and implement a
     *note default(): 38ad. method with another method that returns a
     serializable object for ‘o’ if possible, otherwise it should call
     the superclass implementation (to raise *note TypeError: 2c3.).

     If 'skipkeys' is false (the default), a *note TypeError: 2c3. will
     be raised when trying to encode keys that are not *note str: 44f,
     *note int: 257, *note float: 2f7, *note bool: 46b. or ‘None’.  If
     'skipkeys' is true, such items are simply skipped.

     If 'ensure_ascii' is true (the default), the output is guaranteed
     to have all incoming non-ASCII and non-printable characters
     escaped.  If 'ensure_ascii' is false, all characters will be output
     as-is, except for the characters that must be escaped: quotation
     mark, reverse solidus, and the control characters U+0000 through
     U+001F.

     If 'check_circular' is true (the default), then lists, dicts, and
     custom encoded objects will be checked for circular references
     during encoding to prevent an infinite recursion (which would cause
     a *note RecursionError: d96.).  Otherwise, no such check takes
     place.

     If 'allow_nan' is true (the default), then ‘NaN’, ‘Infinity’, and
     ‘-Infinity’ will be encoded as such.  This behavior is not JSON
     specification compliant, but is consistent with most JavaScript
     based encoders and decoders.  Otherwise, it will be a *note
     ValueError: 202. to encode such floats.

     If 'sort_keys' is true (default: ‘False’), then the output of
     dictionaries will be sorted by key; this is useful for regression
     tests to ensure that JSON serializations can be compared on a
     day-to-day basis.

     If 'indent' is a non-negative integer or string, then JSON array
     elements and object members will be pretty-printed with that indent
     level.  An indent level of 0, negative, or ‘""’ will only insert
     newlines.  ‘None’ (the default) selects the most compact
     representation.  Using a positive integer indent indents that many
     spaces per level.  If 'indent' is a string (such as ‘"\t"’), that
     string is used to indent each level.

     Changed in version 3.2: Allow strings for 'indent' in addition to
     integers.

     If specified, 'separators' should be an ‘(item_separator,
     key_separator)’ tuple.  The default is ‘(', ', ': ')’ if 'indent'
     is ‘None’ and ‘(',', ': ')’ otherwise.  To get the most compact
     JSON representation, you should specify ‘(',', ':')’ to eliminate
     whitespace.

     Changed in version 3.4: Use ‘(',', ': ')’ as default if 'indent' is
     not ‘None’.

     If specified, 'default' should be a function that gets called for
     objects that can’t otherwise be serialized.  It should return a
     JSON encodable version of the object or raise a *note TypeError:
     2c3.  If not specified, ‘TypeError’ is raised.

     Changed in version 3.6: All parameters are now *note keyword-only:
     2a5.

      -- Method: default (o)

          Implement this method in a subclass such that it returns a
          serializable object for 'o', or calls the base implementation
          (to raise a *note TypeError: 2c3.).

          For example, to support arbitrary iterators, you could
          implement ‘default()’ like this:

               def default(self, o):
                  try:
                      iterable = iter(o)
                  except TypeError:
                      pass
                  else:
                      return list(iterable)
                  # Let the base class default method raise the TypeError
                  return super().default(o)

      -- Method: encode (o)

          Return a JSON string representation of a Python data
          structure, 'o'.  For example:

               >>> json.JSONEncoder().encode({"foo": ["bar", "baz"]})
               '{"foo": ["bar", "baz"]}'

      -- Method: iterencode (o)

          Encode the given object, 'o', and yield each string
          representation as available.  For example:

               for chunk in json.JSONEncoder().iterencode(bigobject):
                   mysocket.write(chunk)

   ---------- Footnotes ----------

   (1) https://www.jsonrpc.org


File: python.info,  Node: Exceptions<17>,  Next: Standard Compliance and Interoperability,  Prev: Encoders and Decoders,  Up: json — JSON encoder and decoder

5.20.2.3 Exceptions
...................

 -- Exception: json.JSONDecodeError (msg, doc, pos)

     Subclass of *note ValueError: 202. with the following additional
     attributes:

      -- Attribute: msg

          The unformatted error message.

      -- Attribute: doc

          The JSON document being parsed.

      -- Attribute: pos

          The start index of 'doc' where parsing failed.

      -- Attribute: lineno

          The line corresponding to 'pos'.

      -- Attribute: colno

          The column corresponding to 'pos'.

     Added in version 3.5.


File: python.info,  Node: Standard Compliance and Interoperability,  Next: Command Line Interface,  Prev: Exceptions<17>,  Up: json — JSON encoder and decoder

5.20.2.4 Standard Compliance and Interoperability
.................................................

The JSON format is specified by RFC 7159(1) and by ECMA-404(2).  This
section details this module’s level of compliance with the RFC. For
simplicity, *note JSONEncoder: d6f. and *note JSONDecoder: d70.
subclasses, and parameters other than those explicitly mentioned, are
not considered.

This module does not comply with the RFC in a strict fashion,
implementing some extensions that are valid JavaScript but not valid
JSON. In particular:

   - Infinite and NaN number values are accepted and output;

   - Repeated names within an object are accepted, and only the value of
     the last name-value pair is used.

Since the RFC permits RFC-compliant parsers to accept input texts that
are not RFC-compliant, this module’s deserializer is technically
RFC-compliant under default settings.

* Menu:

* Character Encodings::
* Infinite and NaN Number Values::
* Repeated Names Within an Object::
* Top-level Non-Object, Non-Array Values: Top-level Non-Object Non-Array Values.
* Implementation Limitations::

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc7159.html

   (2) 
https://ecma-international.org/publications-and-standards/standards/ecma-404/


File: python.info,  Node: Character Encodings,  Next: Infinite and NaN Number Values,  Up: Standard Compliance and Interoperability

5.20.2.5 Character Encodings
............................

The RFC requires that JSON be represented using either UTF-8, UTF-16, or
UTF-32, with UTF-8 being the recommended default for maximum
interoperability.

As permitted, though not required, by the RFC, this module’s serializer
sets 'ensure_ascii=True' by default, thus escaping the output so that
the resulting strings only contain printable ASCII characters.

Other than the 'ensure_ascii' parameter, this module is defined strictly
in terms of conversion between Python objects and *note Unicode strings:
44f, and thus does not otherwise directly address the issue of character
encodings.

The RFC prohibits adding a byte order mark (BOM) to the start of a JSON
text, and this module’s serializer does not add a BOM to its output.
The RFC permits, but does not require, JSON deserializers to ignore an
initial BOM in their input.  This module’s deserializer raises a *note
ValueError: 202. when an initial BOM is present.

The RFC does not explicitly forbid JSON strings which contain byte
sequences that don’t correspond to valid Unicode characters (e.g.
unpaired UTF-16 surrogates), but it does note that they may cause
interoperability problems.  By default, this module accepts and outputs
(when present in the original *note str: 44f.) code points for such
sequences.


File: python.info,  Node: Infinite and NaN Number Values,  Next: Repeated Names Within an Object,  Prev: Character Encodings,  Up: Standard Compliance and Interoperability

5.20.2.6 Infinite and NaN Number Values
.......................................

The RFC does not permit the representation of infinite or NaN number
values.  Despite that, by default, this module accepts and outputs
‘Infinity’, ‘-Infinity’, and ‘NaN’ as if they were valid JSON number
literal values:

     >>> # Neither of these calls raises an exception, but the results are not valid JSON
     >>> json.dumps(float('-inf'))
     '-Infinity'
     >>> json.dumps(float('nan'))
     'NaN'
     >>> # Same when deserializing
     >>> json.loads('-Infinity')
     -inf
     >>> json.loads('NaN')
     nan

In the serializer, the 'allow_nan' parameter can be used to alter this
behavior.  In the deserializer, the 'parse_constant' parameter can be
used to alter this behavior.


File: python.info,  Node: Repeated Names Within an Object,  Next: Top-level Non-Object Non-Array Values,  Prev: Infinite and NaN Number Values,  Up: Standard Compliance and Interoperability

5.20.2.7 Repeated Names Within an Object
........................................

The RFC specifies that the names within a JSON object should be unique,
but does not mandate how repeated names in JSON objects should be
handled.  By default, this module does not raise an exception; instead,
it ignores all but the last name-value pair for a given name:

     >>> weird_json = '{"x": 1, "x": 2, "x": 3}'
     >>> json.loads(weird_json)
     {'x': 3}

The 'object_pairs_hook' parameter can be used to alter this behavior.


File: python.info,  Node: Top-level Non-Object Non-Array Values,  Next: Implementation Limitations,  Prev: Repeated Names Within an Object,  Up: Standard Compliance and Interoperability

5.20.2.8 Top-level Non-Object, Non-Array Values
...............................................

The old version of JSON specified by the obsolete RFC 4627(1) required
that the top-level value of a JSON text must be either a JSON object or
array (Python *note dict: 256. or *note list: 614.), and could not be a
JSON null, boolean, number, or string value.  RFC 7159(2) removed that
restriction, and this module does not and has never implemented that
restriction in either its serializer or its deserializer.

Regardless, for maximum interoperability, you may wish to voluntarily
adhere to the restriction yourself.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc4627.html

   (2) https://datatracker.ietf.org/doc/html/rfc7159.html


File: python.info,  Node: Implementation Limitations,  Prev: Top-level Non-Object Non-Array Values,  Up: Standard Compliance and Interoperability

5.20.2.9 Implementation Limitations
...................................

Some JSON deserializer implementations may set limits on:

   * the size of accepted JSON texts

   * the maximum level of nesting of JSON objects and arrays

   * the range and precision of JSON numbers

   * the content and maximum length of JSON strings

This module does not impose any such limits beyond those of the relevant
Python datatypes themselves or the Python interpreter itself.

When serializing to JSON, beware any such limitations in applications
that may consume your JSON. In particular, it is common for JSON numbers
to be deserialized into IEEE 754 double precision numbers and thus
subject to that representation’s range and precision limitations.  This
is especially relevant when serializing Python *note int: 257. values of
extremely large magnitude, or when serializing instances of “exotic”
numerical types such as *note decimal.Decimal: 29d.


File: python.info,  Node: Command Line Interface,  Prev: Standard Compliance and Interoperability,  Up: json — JSON encoder and decoder

5.20.2.10 Command Line Interface
................................

'Source code:' Lib/json/tool.py(1)

__________________________________________________________________

The ‘json.tool’ module provides a simple command line interface to
validate and pretty-print JSON objects.

If the optional ‘infile’ and ‘outfile’ arguments are not specified,
*note sys.stdin: 540. and *note sys.stdout: aec. will be used
respectively:

     $ echo '{"json": "obj"}' | python -m json.tool
     {
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -m json.tool
     Expecting property name enclosed in double quotes: line 1 column 2 (char 1)

Changed in version 3.5: The output is now in the same order as the
input.  Use the *note -sort-keys: 38c1. option to sort the output of
dictionaries alphabetically by key.

* Menu:

* Command line options::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/json/tool.py


File: python.info,  Node: Command line options,  Up: Command Line Interface

5.20.2.11 Command line options
..............................

 -- Option: infile

     The JSON file to be validated or pretty-printed:

          $ python -m json.tool mp_films.json
          [
              {
                  "title": "And Now for Something Completely Different",
                  "year": 1971
              },
              {
                  "title": "Monty Python and the Holy Grail",
                  "year": 1975
              }
          ]

     If 'infile' is not specified, read from *note sys.stdin: 540.

 -- Option: outfile

     Write the output of the 'infile' to the given 'outfile'.
     Otherwise, write it to *note sys.stdout: aec.

 -- Option: --sort-keys

     Sort the output of dictionaries alphabetically by key.

     Added in version 3.5.

 -- Option: --no-ensure-ascii

     Disable escaping of non-ascii characters, see *note json.dumps():
     d6e. for more information.

     Added in version 3.9.

 -- Option: --json-lines

     Parse every input line as separate JSON object.

     Added in version 3.8.

 -- Option: --indent, --tab, --no-indent, --compact

     Mutually exclusive options for whitespace control.

     Added in version 3.9.

 -- Option: -h, --help

     Show the help message.


File: python.info,  Node: mailbox — Manipulate mailboxes in various formats,  Next: mimetypes — Map filenames to MIME types,  Prev: json — JSON encoder and decoder,  Up: Internet Data Handling

5.20.3 ‘mailbox’ — Manipulate mailboxes in various formats
----------------------------------------------------------

'Source code:' Lib/mailbox.py(1)

__________________________________________________________________

This module defines two classes, *note Mailbox: 1293. and *note Message:
1297, for accessing and manipulating on-disk mailboxes and the messages
they contain.  ‘Mailbox’ offers a dictionary-like mapping from keys to
messages.  ‘Message’ extends the *note email.message: 44. module’s *note
Message: 27c. class with format-specific state and behavior.  Supported
mailbox formats are Maildir, mbox, MH, Babyl, and MMDF.

See also
........

Module *note email: 3b.

     Represent and manipulate messages.

* Menu:

* Mailbox objects::
* Message objects::
* Exceptions: Exceptions<18>.
* Examples: Examples<23>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/mailbox.py


File: python.info,  Node: Mailbox objects,  Next: Message objects,  Up: mailbox — Manipulate mailboxes in various formats

5.20.3.1 ‘Mailbox’ objects
..........................

 -- Class: mailbox.Mailbox

     A mailbox, which may be inspected and modified.

     The ‘Mailbox’ class defines an interface and is not intended to be
     instantiated.  Instead, format-specific subclasses should inherit
     from ‘Mailbox’ and your code should instantiate a particular
     subclass.

     The ‘Mailbox’ interface is dictionary-like, with small keys
     corresponding to messages.  Keys are issued by the ‘Mailbox’
     instance with which they will be used and are only meaningful to
     that ‘Mailbox’ instance.  A key continues to identify a message
     even if the corresponding message is modified, such as by replacing
     it with another message.

     Messages may be added to a ‘Mailbox’ instance using the set-like
     method *note add(): 1292. and removed using a ‘del’ statement or
     the set-like methods *note remove(): 38d2. and *note discard():
     38d3.

     ‘Mailbox’ interface semantics differ from dictionary semantics in
     some noteworthy ways.  Each time a message is requested, a new
     representation (typically a *note Message: 1297. instance) is
     generated based upon the current state of the mailbox.  Similarly,
     when a message is added to a ‘Mailbox’ instance, the provided
     message representation’s contents are copied.  In neither case is a
     reference to the message representation kept by the ‘Mailbox’
     instance.

     The default ‘Mailbox’ *note iterator: 1ac. iterates over message
     representations, not keys as the default *note dictionary: 256.
     iterator does.  Moreover, modification of a mailbox during
     iteration is safe and well-defined.  Messages added to the mailbox
     after an iterator is created will not be seen by the iterator.
     Messages removed from the mailbox before the iterator yields them
     will be silently skipped, though using a key from an iterator may
     result in a *note KeyError: 345. exception if the corresponding
     message is subsequently removed.

          Warning: Be very cautious when modifying mailboxes that might
          be simultaneously changed by some other process.  The safest
          mailbox format to use for such tasks is *note Maildir: 41f.;
          try to avoid using single-file formats such as *note mbox:
          1792. for concurrent writing.  If you’re modifying a mailbox,
          you 'must' lock it by calling the *note lock(): 38d4. and
          *note unlock(): 38d5. methods 'before' reading any messages in
          the file or making any changes by adding or deleting a
          message.  Failing to lock the mailbox runs the risk of losing
          messages or corrupting the entire mailbox.

     ‘Mailbox’ instances have the following methods:

      -- Method: add (message)

          Add 'message' to the mailbox and return the key that has been
          assigned to it.

          Parameter 'message' may be a *note Message: 1297. instance, an
          *note email.message.Message: 27c. instance, a string, a byte
          string, or a file-like object (which should be open in binary
          mode).  If 'message' is an instance of the appropriate
          format-specific ‘Message’ subclass (e.g., if it’s an *note
          mboxMessage: 378f. instance and this is an *note mbox: 1792.
          instance), its format-specific information is used.
          Otherwise, reasonable defaults for format-specific information
          are used.

          Changed in version 3.2: Support for binary input was added.

      -- Method: remove (key)
      -- Method: __delitem__ (key)
      -- Method: discard (key)

          Delete the message corresponding to 'key' from the mailbox.

          If no such message exists, a *note KeyError: 345. exception is
          raised if the method was called as ‘remove()’ or
          ‘__delitem__()’ but no exception is raised if the method was
          called as ‘discard()’.  The behavior of ‘discard()’ may be
          preferred if the underlying mailbox format supports concurrent
          modification by other processes.

      -- Method: __setitem__ (key, message)

          Replace the message corresponding to 'key' with 'message'.
          Raise a *note KeyError: 345. exception if no message already
          corresponds to 'key'.

          As with *note add(): 1292, parameter 'message' may be a *note
          Message: 1297. instance, an *note email.message.Message: 27c.
          instance, a string, a byte string, or a file-like object
          (which should be open in binary mode).  If 'message' is an
          instance of the appropriate format-specific ‘Message’ subclass
          (e.g., if it’s an *note mboxMessage: 378f. instance and this
          is an *note mbox: 1792. instance), its format-specific
          information is used.  Otherwise, the format-specific
          information of the message that currently corresponds to 'key'
          is left unchanged.

      -- Method: iterkeys ()

          Return an *note iterator: 1ac. over all keys

      -- Method: keys ()

          The same as *note iterkeys(): 38d8, except that a *note list:
          614. is returned rather than an *note iterator: 1ac.

      -- Method: itervalues ()
      -- Method: __iter__ ()

          Return an *note iterator: 1ac. over representations of all
          messages.  The messages are represented as instances of the
          appropriate format-specific *note Message: 1297. subclass
          unless a custom message factory was specified when the
          ‘Mailbox’ instance was initialized.

               Note: The behavior of ‘__iter__()’ is unlike that of
               dictionaries, which iterate over keys.

      -- Method: values ()

          The same as *note itervalues(): 38da, except that a *note
          list: 614. is returned rather than an *note iterator: 1ac.

      -- Method: iteritems ()

          Return an *note iterator: 1ac. over ('key', 'message') pairs,
          where 'key' is a key and 'message' is a message
          representation.  The messages are represented as instances of
          the appropriate format-specific *note Message: 1297. subclass
          unless a custom message factory was specified when the
          ‘Mailbox’ instance was initialized.

      -- Method: items ()

          The same as *note iteritems(): 38dd, except that a *note list:
          614. of pairs is returned rather than an *note iterator: 1ac.
          of pairs.

      -- Method: get (key, default=None)
      -- Method: __getitem__ (key)

          Return a representation of the message corresponding to 'key'.
          If no such message exists, 'default' is returned if the method
          was called as ‘get()’ and a *note KeyError: 345. exception is
          raised if the method was called as ‘__getitem__()’.  The
          message is represented as an instance of the appropriate
          format-specific *note Message: 1297. subclass unless a custom
          message factory was specified when the ‘Mailbox’ instance was
          initialized.

      -- Method: get_message (key)

          Return a representation of the message corresponding to 'key'
          as an instance of the appropriate format-specific *note
          Message: 1297. subclass, or raise a *note KeyError: 345.
          exception if no such message exists.

      -- Method: get_bytes (key)

          Return a byte representation of the message corresponding to
          'key', or raise a *note KeyError: 345. exception if no such
          message exists.

          Added in version 3.2.

      -- Method: get_string (key)

          Return a string representation of the message corresponding to
          'key', or raise a *note KeyError: 345. exception if no such
          message exists.  The message is processed through *note
          email.message.Message: 27c. to convert it to a 7bit clean
          representation.

      -- Method: get_file (key)

          Return a *note file-like: 15f4. representation of the message
          corresponding to 'key', or raise a *note KeyError: 345.
          exception if no such message exists.  The file-like object
          behaves as if open in binary mode.  This file should be closed
          once it is no longer needed.

          Changed in version 3.2: The file object really is a *note
          binary file: 1e26.; previously it was incorrectly returned in
          text mode.  Also, the *note file-like object: 15f4. now
          supports the *note context manager: 5d7. protocol: you can use
          a *note with: 5d5. statement to automatically close it.

               Note: Unlike other representations of messages, *note
               file-like: 15f4. representations are not necessarily
               independent of the ‘Mailbox’ instance that created them
               or of the underlying mailbox.  More specific
               documentation is provided by each subclass.

      -- Method: __contains__ (key)

          Return ‘True’ if 'key' corresponds to a message, ‘False’
          otherwise.

      -- Method: __len__ ()

          Return a count of messages in the mailbox.

      -- Method: clear ()

          Delete all messages from the mailbox.

      -- Method: pop (key, default=None)

          Return a representation of the message corresponding to 'key'
          and delete the message.  If no such message exists, return
          'default'.  The message is represented as an instance of the
          appropriate format-specific *note Message: 1297. subclass
          unless a custom message factory was specified when the
          ‘Mailbox’ instance was initialized.

      -- Method: popitem ()

          Return an arbitrary ('key', 'message') pair, where 'key' is a
          key and 'message' is a message representation, and delete the
          corresponding message.  If the mailbox is empty, raise a *note
          KeyError: 345. exception.  The message is represented as an
          instance of the appropriate format-specific *note Message:
          1297. subclass unless a custom message factory was specified
          when the ‘Mailbox’ instance was initialized.

      -- Method: update (arg)

          Parameter 'arg' should be a 'key'-to-'message' mapping or an
          iterable of ('key', 'message') pairs.  Updates the mailbox so
          that, for each given 'key' and 'message', the message
          corresponding to 'key' is set to 'message' as if by using
          *note __setitem__(): 38d7.  As with ‘__setitem__()’, each
          'key' must already correspond to a message in the mailbox or
          else a *note KeyError: 345. exception will be raised, so in
          general it is incorrect for 'arg' to be a ‘Mailbox’ instance.

               Note: Unlike with dictionaries, keyword arguments are not
               supported.

      -- Method: flush ()

          Write any pending changes to the filesystem.  For some
          ‘Mailbox’ subclasses, changes are always written immediately
          and ‘flush()’ does nothing, but you should still make a habit
          of calling this method.

      -- Method: lock ()

          Acquire an exclusive advisory lock on the mailbox so that
          other processes know not to modify it.  An *note
          ExternalClashError: 38e8. is raised if the lock is not
          available.  The particular locking mechanisms used depend upon
          the mailbox format.  You should 'always' lock the mailbox
          before making any modifications to its contents.

      -- Method: unlock ()

          Release the lock on the mailbox, if any.

      -- Method: close ()

          Flush the mailbox, unlock it if necessary, and close any open
          files.  For some ‘Mailbox’ subclasses, this method does
          nothing.

* Menu:

* Maildir objects::
* mbox objects::
* MH objects::
* Babyl objects::
* MMDF objects::


File: python.info,  Node: Maildir objects,  Next: mbox objects,  Up: Mailbox objects

5.20.3.2 ‘Maildir’ objects
..........................

 -- Class: mailbox.Maildir (dirname, factory=None, create=True)

     A subclass of *note Mailbox: 1293. for mailboxes in Maildir format.
     Parameter 'factory' is a callable object that accepts a file-like
     message representation (which behaves as if opened in binary mode)
     and returns a custom representation.  If 'factory' is ‘None’, *note
     MaildirMessage: 38ec. is used as the default message
     representation.  If 'create' is ‘True’, the mailbox is created if
     it does not exist.

     If 'create' is ‘True’ and the 'dirname' path exists, it will be
     treated as an existing maildir without attempting to verify its
     directory layout.

     It is for historical reasons that 'dirname' is named as such rather
     than 'path'.

     Maildir is a directory-based mailbox format invented for the qmail
     mail transfer agent and now widely supported by other programs.
     Messages in a Maildir mailbox are stored in separate files within a
     common directory structure.  This design allows Maildir mailboxes
     to be accessed and modified by multiple unrelated programs without
     data corruption, so file locking is unnecessary.

     Maildir mailboxes contain three subdirectories, namely: ‘tmp’,
     ‘new’, and ‘cur’.  Messages are created momentarily in the ‘tmp’
     subdirectory and then moved to the ‘new’ subdirectory to finalize
     delivery.  A mail user agent may subsequently move the message to
     the ‘cur’ subdirectory and store information about the state of the
     message in a special “info” section appended to its file name.

     Folders of the style introduced by the Courier mail transfer agent
     are also supported.  Any subdirectory of the main mailbox is
     considered a folder if ‘'.'’ is the first character in its name.
     Folder names are represented by ‘Maildir’ without the leading
     ‘'.'’.  Each folder is itself a Maildir mailbox but should not
     contain other folders.  Instead, a logical nesting is indicated
     using ‘'.'’ to delimit levels, e.g., “Archived.2005.07”.

      -- Attribute: colon

          The Maildir specification requires the use of a colon (‘':'’)
          in certain message file names.  However, some operating
          systems do not permit this character in file names, If you
          wish to use a Maildir-like format on such an operating system,
          you should specify another character to use instead.  The
          exclamation point (‘'!'’) is a popular choice.  For example:

               import mailbox
               mailbox.Maildir.colon = '!'

          The ‘colon’ attribute may also be set on a per-instance basis.

     Changed in version 3.13: ‘Maildir’ now ignores files with a leading
     dot.

     ‘Maildir’ instances have all of the methods of *note Mailbox: 1293.
     in addition to the following:

      -- Method: list_folders ()

          Return a list of the names of all folders.

      -- Method: get_folder (folder)

          Return a ‘Maildir’ instance representing the folder whose name
          is 'folder'.  A *note NoSuchMailboxError: 38f0. exception is
          raised if the folder does not exist.

      -- Method: add_folder (folder)

          Create a folder whose name is 'folder' and return a ‘Maildir’
          instance representing it.

      -- Method: remove_folder (folder)

          Delete the folder whose name is 'folder'.  If the folder
          contains any messages, a *note NotEmptyError: 38f3. exception
          will be raised and the folder will not be deleted.

      -- Method: clean ()

          Delete temporary files from the mailbox that have not been
          accessed in the last 36 hours.  The Maildir specification says
          that mail-reading programs should do this occasionally.

      -- Method: get_flags (key)

          Return as a string the flags that are set on the message
          corresponding to 'key'.  This is the same as
          ‘get_message(key).get_flags()’ but much faster, because it
          does not open the message file.  Use this method when
          iterating over the keys to determine which messages are
          interesting to get.

          If you do have a *note MaildirMessage: 38ec. object, use its
          *note get_flags(): 38f5. method instead, because changes made
          by the message’s *note set_flags(): 38f6, *note add_flag():
          38f7. and *note remove_flag(): 38f8. methods are not reflected
          here until the mailbox’s *note __setitem__(): 38f9. method is
          called.

          Added in version 3.13.

      -- Method: set_flags (key, flags)

          On the message corresponding to 'key', set the flags specified
          by 'flags' and unset all others.  Calling
          ‘some_mailbox.set_flags(key, flags)’ is similar to

               one_message = some_mailbox.get_message(key)
               one_message.set_flags(flags)
               some_mailbox[key] = one_message

          but faster, because it does not open the message file.

          If you do have a *note MaildirMessage: 38ec. object, use its
          *note set_flags(): 38f6. method instead, because changes made
          with this mailbox method will not be visible to the message
          object’s method, *note get_flags(): 38f5.

          Added in version 3.13.

      -- Method: add_flag (key, flag)

          On the message corresponding to 'key', set the flags specified
          by 'flag' without changing other flags.  To add more than one
          flag at a time, 'flag' may be a string of more than one
          character.

          Considerations for using this method versus the message
          object’s *note add_flag(): 38f7. method are similar to those
          for *note set_flags(): 17e2.; see the discussion there.

          Added in version 3.13.

      -- Method: remove_flag (key, flag)

          On the message corresponding to 'key', unset the flags
          specified by 'flag' without changing other flags.  To remove
          more than one flag at a time, 'flag' may be a string of more
          than one character.

          Considerations for using this method versus the message
          object’s *note remove_flag(): 38f8. method are similar to
          those for *note set_flags(): 17e2.; see the discussion there.

          Added in version 3.13.

      -- Method: get_info (key)

          Return a string containing the info for the message
          corresponding to 'key'.  This is the same as
          ‘get_message(key).get_info()’ but much faster, because it does
          not open the message file.  Use this method when iterating
          over the keys to determine which messages are interesting to
          get.

          If you do have a *note MaildirMessage: 38ec. object, use its
          *note get_info(): 38fa. method instead, because changes made
          by the message’s *note set_info(): 38fb. method are not
          reflected here until the mailbox’s *note __setitem__(): 38f9.
          method is called.

          Added in version 3.13.

      -- Method: set_info (key, info)

          Set the info of the message corresponding to 'key' to 'info'.
          Calling ‘some_mailbox.set_info(key, flags)’ is similar to

               one_message = some_mailbox.get_message(key)
               one_message.set_info(info)
               some_mailbox[key] = one_message

          but faster, because it does not open the message file.

          If you do have a *note MaildirMessage: 38ec. object, use its
          *note set_info(): 38fb. method instead, because changes made
          with this mailbox method will not be visible to the message
          object’s method, *note get_info(): 38fa.

          Added in version 3.13.

     Some *note Mailbox: 1293. methods implemented by ‘Maildir’ deserve
     special remarks:

      -- Method: add (message)
      -- Method: __setitem__ (key, message)
      -- Method: update (arg)

               Warning: These methods generate unique file names based
               upon the current process ID. When using multiple threads,
               undetected name clashes may occur and cause corruption of
               the mailbox unless threads are coordinated to avoid using
               these methods to manipulate the same mailbox
               simultaneously.

      -- Method: flush ()

          All changes to Maildir mailboxes are immediately applied, so
          this method does nothing.

      -- Method: lock ()
      -- Method: unlock ()

          Maildir mailboxes do not support (or require) locking, so
          these methods do nothing.

      -- Method: close ()

          ‘Maildir’ instances do not keep any open files and the
          underlying mailboxes do not support locking, so this method
          does nothing.

      -- Method: get_file (key)

          Depending upon the host platform, it may not be possible to
          modify or remove the underlying message while the returned
          file remains open.

See also
........

maildir man page from Courier(1)

     A specification of the format.  Describes a common extension for
     supporting folders.

Using maildir format(2)

     Notes on Maildir by its inventor.  Includes an updated
     name-creation scheme and details on “info” semantics.

   ---------- Footnotes ----------

   (1) https://www.courier-mta.org/maildir.html

   (2) https://cr.yp.to/proto/maildir.html


File: python.info,  Node: mbox objects,  Next: MH objects,  Prev: Maildir objects,  Up: Mailbox objects

5.20.3.3 ‘mbox’ objects
.......................

 -- Class: mailbox.mbox (path, factory=None, create=True)

     A subclass of *note Mailbox: 1293. for mailboxes in mbox format.
     Parameter 'factory' is a callable object that accepts a file-like
     message representation (which behaves as if opened in binary mode)
     and returns a custom representation.  If 'factory' is ‘None’, *note
     mboxMessage: 378f. is used as the default message representation.
     If 'create' is ‘True’, the mailbox is created if it does not exist.

     The mbox format is the classic format for storing mail on Unix
     systems.  All messages in an mbox mailbox are stored in a single
     file with the beginning of each message indicated by a line whose
     first five characters are “From “.

     Several variations of the mbox format exist to address perceived
     shortcomings in the original.  In the interest of compatibility,
     ‘mbox’ implements the original format, which is sometimes referred
     to as 'mboxo'.  This means that the ‘Content-Length’ header, if
     present, is ignored and that any occurrences of “From “ at the
     beginning of a line in a message body are transformed to “>From “
     when storing the message, although occurrences of “>From “ are not
     transformed to “From “ when reading the message.

     Some *note Mailbox: 1293. methods implemented by ‘mbox’ deserve
     special remarks:

      -- Method: get_bytes (key, from_=False)

          Note: This method has an extra parameter ('from_') compared
          with other classes.  The first line of an mbox file entry is
          the Unix “From “ line.  If 'from_' is False, the first line of
          the file is dropped.

      -- Method: get_file (key, from_=False)

          Using the file after calling *note flush(): 1755. or *note
          close(): 38e9. on the ‘mbox’ instance may yield unpredictable
          results or raise an exception.

          Note: This method has an extra parameter ('from_') compared
          with other classes.  The first line of an mbox file entry is
          the Unix “From “ line.  If 'from_' is False, the first line of
          the file is dropped.

      -- Method: get_string (key, from_=False)

          Note: This method has an extra parameter ('from_') compared
          with other classes.  The first line of an mbox file entry is
          the Unix “From “ line.  If 'from_' is False, the first line of
          the file is dropped.

      -- Method: lock ()
      -- Method: unlock ()

          Three locking mechanisms are used—dot locking and, if
          available, the ‘flock()’ and ‘lockf()’ system calls.

See also
........

mbox man page from tin(1)

     A specification of the format, with details on locking.

Configuring Netscape Mail on Unix: Why The Content-Length Format is Bad(2)

     An argument for using the original mbox format rather than a
     variation.

"mbox" is a family of several mutually incompatible mailbox formats(3)

     A history of mbox variations.

   ---------- Footnotes ----------

   (1) http://www.tin.org/bin/man.cgi?section=5&topic=mbox

   (2) https://www.jwz.org/doc/content-length.html

   (3) 
https://www.loc.gov/preservation/digital/formats/fdd/fdd000383.shtml


File: python.info,  Node: MH objects,  Next: Babyl objects,  Prev: mbox objects,  Up: Mailbox objects

5.20.3.4 ‘MH’ objects
.....................

 -- Class: mailbox.MH (path, factory=None, create=True)

     A subclass of *note Mailbox: 1293. for mailboxes in MH format.
     Parameter 'factory' is a callable object that accepts a file-like
     message representation (which behaves as if opened in binary mode)
     and returns a custom representation.  If 'factory' is ‘None’, *note
     MHMessage: 390c. is used as the default message representation.  If
     'create' is ‘True’, the mailbox is created if it does not exist.

     MH is a directory-based mailbox format invented for the MH Message
     Handling System, a mail user agent.  Each message in an MH mailbox
     resides in its own file.  An MH mailbox may contain other MH
     mailboxes (called 'folders') in addition to messages.  Folders may
     be nested indefinitely.  MH mailboxes also support 'sequences',
     which are named lists used to logically group messages without
     moving them to sub-folders.  Sequences are defined in a file called
     ‘.mh_sequences’ in each folder.

     The ‘MH’ class manipulates MH mailboxes, but it does not attempt to
     emulate all of ‘mh’’s behaviors.  In particular, it does not modify
     and is not affected by the ‘context’ or ‘.mh_profile’ files that
     are used by ‘mh’ to store its state and configuration.

     ‘MH’ instances have all of the methods of *note Mailbox: 1293. in
     addition to the following:

     Changed in version 3.13: Supported folders that don’t contain a
     ‘.mh_sequences’ file.

      -- Method: list_folders ()

          Return a list of the names of all folders.

      -- Method: get_folder (folder)

          Return an ‘MH’ instance representing the folder whose name is
          'folder'.  A *note NoSuchMailboxError: 38f0. exception is
          raised if the folder does not exist.

      -- Method: add_folder (folder)

          Create a folder whose name is 'folder' and return an ‘MH’
          instance representing it.

      -- Method: remove_folder (folder)

          Delete the folder whose name is 'folder'.  If the folder
          contains any messages, a *note NotEmptyError: 38f3. exception
          will be raised and the folder will not be deleted.

      -- Method: get_sequences ()

          Return a dictionary of sequence names mapped to key lists.  If
          there are no sequences, the empty dictionary is returned.

      -- Method: set_sequences (sequences)

          Re-define the sequences that exist in the mailbox based upon
          'sequences', a dictionary of names mapped to key lists, like
          returned by *note get_sequences(): 3911.

      -- Method: pack ()

          Rename messages in the mailbox as necessary to eliminate gaps
          in numbering.  Entries in the sequences list are updated
          correspondingly.

               Note: Already-issued keys are invalidated by this
               operation and should not be subsequently used.

     Some *note Mailbox: 1293. methods implemented by ‘MH’ deserve
     special remarks:

      -- Method: remove (key)
      -- Method: __delitem__ (key)
      -- Method: discard (key)

          These methods immediately delete the message.  The MH
          convention of marking a message for deletion by prepending a
          comma to its name is not used.

      -- Method: lock ()
      -- Method: unlock ()

          Three locking mechanisms are used—dot locking and, if
          available, the ‘flock()’ and ‘lockf()’ system calls.  For MH
          mailboxes, locking the mailbox means locking the
          ‘.mh_sequences’ file and, only for the duration of any
          operations that affect them, locking individual message files.

      -- Method: get_file (key)

          Depending upon the host platform, it may not be possible to
          remove the underlying message while the returned file remains
          open.

      -- Method: flush ()

          All changes to MH mailboxes are immediately applied, so this
          method does nothing.

      -- Method: close ()

          ‘MH’ instances do not keep any open files, so this method is
          equivalent to *note unlock(): 3918.

See also
........

nmh - Message Handling System(1)

     Home page of ‘nmh’, an updated version of the original ‘mh’.

MH & nmh: Email for Users & Programmers(2)

     A GPL-licensed book on ‘mh’ and ‘nmh’, with some information on the
     mailbox format.

   ---------- Footnotes ----------

   (1) https://www.nongnu.org/nmh/

   (2) https://rand-mh.sourceforge.io/book/


File: python.info,  Node: Babyl objects,  Next: MMDF objects,  Prev: MH objects,  Up: Mailbox objects

5.20.3.5 ‘Babyl’ objects
........................

 -- Class: mailbox.Babyl (path, factory=None, create=True)

     A subclass of *note Mailbox: 1293. for mailboxes in Babyl format.
     Parameter 'factory' is a callable object that accepts a file-like
     message representation (which behaves as if opened in binary mode)
     and returns a custom representation.  If 'factory' is ‘None’, *note
     BabylMessage: 391f. is used as the default message representation.
     If 'create' is ‘True’, the mailbox is created if it does not exist.

     Babyl is a single-file mailbox format used by the Rmail mail user
     agent included with Emacs.  The beginning of a message is indicated
     by a line containing the two characters Control-Underscore
     (‘'\037'’) and Control-L (‘'\014'’).  The end of a message is
     indicated by the start of the next message or, in the case of the
     last message, a line containing a Control-Underscore (‘'\037'’)
     character.

     Messages in a Babyl mailbox have two sets of headers, original
     headers and so-called visible headers.  Visible headers are
     typically a subset of the original headers that have been
     reformatted or abridged to be more attractive.  Each message in a
     Babyl mailbox also has an accompanying list of 'labels', or short
     strings that record extra information about the message, and a list
     of all user-defined labels found in the mailbox is kept in the
     Babyl options section.

     ‘Babyl’ instances have all of the methods of *note Mailbox: 1293.
     in addition to the following:

      -- Method: get_labels ()

          Return a list of the names of all user-defined labels used in
          the mailbox.

               Note: The actual messages are inspected to determine
               which labels exist in the mailbox rather than consulting
               the list of labels in the Babyl options section, but the
               Babyl section is updated whenever the mailbox is
               modified.

     Some *note Mailbox: 1293. methods implemented by ‘Babyl’ deserve
     special remarks:

      -- Method: get_file (key)

          In Babyl mailboxes, the headers of a message are not stored
          contiguously with the body of the message.  To generate a
          file-like representation, the headers and body are copied
          together into an *note io.BytesIO: ed8. instance, which has an
          API identical to that of a file.  As a result, the file-like
          object is truly independent of the underlying mailbox but does
          not save memory compared to a string representation.

      -- Method: lock ()
      -- Method: unlock ()

          Three locking mechanisms are used—dot locking and, if
          available, the ‘flock()’ and ‘lockf()’ system calls.

See also
........

Format of Version 5 Babyl Files(1)

     A specification of the Babyl format.

Reading Mail with Rmail(2)

     The Rmail manual, with some information on Babyl semantics.

   ---------- Footnotes ----------

   (1) https://quimby.gnus.org/notes/BABYL

   (2) 
https://www.gnu.org/software/emacs/manual/html_node/emacs/Rmail.html


File: python.info,  Node: MMDF objects,  Prev: Babyl objects,  Up: Mailbox objects

5.20.3.6 ‘MMDF’ objects
.......................

 -- Class: mailbox.MMDF (path, factory=None, create=True)

     A subclass of *note Mailbox: 1293. for mailboxes in MMDF format.
     Parameter 'factory' is a callable object that accepts a file-like
     message representation (which behaves as if opened in binary mode)
     and returns a custom representation.  If 'factory' is ‘None’, *note
     MMDFMessage: 3926. is used as the default message representation.
     If 'create' is ‘True’, the mailbox is created if it does not exist.

     MMDF is a single-file mailbox format invented for the Multichannel
     Memorandum Distribution Facility, a mail transfer agent.  Each
     message is in the same form as an mbox message but is bracketed
     before and after by lines containing four Control-A (‘'\001'’)
     characters.  As with the mbox format, the beginning of each message
     is indicated by a line whose first five characters are “From “, but
     additional occurrences of “From “ are not transformed to “>From “
     when storing messages because the extra message separator lines
     prevent mistaking such occurrences for the starts of subsequent
     messages.

     Some *note Mailbox: 1293. methods implemented by ‘MMDF’ deserve
     special remarks:

      -- Method: get_bytes (key, from_=False)

          Note: This method has an extra parameter ('from_') compared
          with other classes.  The first line of an mbox file entry is
          the Unix “From “ line.  If 'from_' is False, the first line of
          the file is dropped.

      -- Method: get_file (key, from_=False)

          Using the file after calling *note flush(): 1755. or *note
          close(): 38e9. on the ‘MMDF’ instance may yield unpredictable
          results or raise an exception.

          Note: This method has an extra parameter ('from_') compared
          with other classes.  The first line of an mbox file entry is
          the Unix “From “ line.  If 'from_' is False, the first line of
          the file is dropped.

      -- Method: lock ()
      -- Method: unlock ()

          Three locking mechanisms are used—dot locking and, if
          available, the ‘flock()’ and ‘lockf()’ system calls.

See also
........

mmdf man page from tin(1)

     A specification of MMDF format from the documentation of tin, a
     newsreader.

MMDF(2)

     A Wikipedia article describing the Multichannel Memorandum
     Distribution Facility.

   ---------- Footnotes ----------

   (1) http://www.tin.org/bin/man.cgi?section=5&topic=mmdf

   (2) https://en.wikipedia.org/wiki/MMDF


File: python.info,  Node: Message objects,  Next: Exceptions<18>,  Prev: Mailbox objects,  Up: mailbox — Manipulate mailboxes in various formats

5.20.3.7 ‘Message’ objects
..........................

 -- Class: mailbox.Message (message=None)

     A subclass of the *note email.message: 44. module’s *note Message:
     27c.  Subclasses of ‘mailbox.Message’ add mailbox-format-specific
     state and behavior.

     If 'message' is omitted, the new instance is created in a default,
     empty state.  If 'message' is an *note email.message.Message: 27c.
     instance, its contents are copied; furthermore, any format-specific
     information is converted insofar as possible if 'message' is a
     ‘Message’ instance.  If 'message' is a string, a byte string, or a
     file, it should contain an RFC 5322(1)-compliant message, which is
     read and parsed.  Files should be open in binary mode, but text
     mode files are accepted for backward compatibility.

     The format-specific state and behaviors offered by subclasses vary,
     but in general it is only the properties that are not specific to a
     particular mailbox that are supported (although presumably the
     properties are specific to a particular mailbox format).  For
     example, file offsets for single-file mailbox formats and file
     names for directory-based mailbox formats are not retained, because
     they are only applicable to the original mailbox.  But state such
     as whether a message has been read by the user or marked as
     important is retained, because it applies to the message itself.

     There is no requirement that ‘Message’ instances be used to
     represent messages retrieved using *note Mailbox: 1293. instances.
     In some situations, the time and memory required to generate
     ‘Message’ representations might not be acceptable.  For such
     situations, ‘Mailbox’ instances also offer string and file-like
     representations, and a custom message factory may be specified when
     a ‘Mailbox’ instance is initialized.

* Menu:

* MaildirMessage objects::
* mboxMessage objects::
* MHMessage objects::
* BabylMessage objects::
* MMDFMessage objects::

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: MaildirMessage objects,  Next: mboxMessage objects,  Up: Message objects

5.20.3.8 ‘MaildirMessage’ objects
.................................

 -- Class: mailbox.MaildirMessage (message=None)

     A message with Maildir-specific behaviors.  Parameter 'message' has
     the same meaning as with the *note Message: 1297. constructor.

     Typically, a mail user agent application moves all of the messages
     in the ‘new’ subdirectory to the ‘cur’ subdirectory after the first
     time the user opens and closes the mailbox, recording that the
     messages are old whether or not they’ve actually been read.  Each
     message in ‘cur’ has an “info” section added to its file name to
     store information about its state.  (Some mail readers may also add
     an “info” section to messages in ‘new’.)  The “info” section may
     take one of two forms: it may contain “2,” followed by a list of
     standardized flags (e.g., “2,FR”) or it may contain “1,” followed
     by so-called experimental information.  Standard flags for Maildir
     messages are as follows:

     Flag       Meaning       Explanation
                              
     --------------------------------------------------------------
                              
     D          Draft         Under composition
                              
                              
     F          Flagged       Marked as important
                              
                              
     P          Passed        Forwarded, resent, or bounced
                              
                              
     R          Replied       Replied to
                              
                              
     S          Seen          Read
                              
                              
     T          Trashed       Marked for subsequent deletion
                              

     ‘MaildirMessage’ instances offer the following methods:

      -- Method: get_subdir ()

          Return either “new” (if the message should be stored in the
          ‘new’ subdirectory) or “cur” (if the message should be stored
          in the ‘cur’ subdirectory).

               Note: A message is typically moved from ‘new’ to ‘cur’
               after its mailbox has been accessed, whether or not the
               message has been read.  A message ‘msg’ has been read if
               ‘"S" in msg.get_flags()’ is ‘True’.

      -- Method: set_subdir (subdir)

          Set the subdirectory the message should be stored in.
          Parameter 'subdir' must be either “new” or “cur”.

      -- Method: get_flags ()

          Return a string specifying the flags that are currently set.
          If the message complies with the standard Maildir format, the
          result is the concatenation in alphabetical order of zero or
          one occurrence of each of ‘'D'’, ‘'F'’, ‘'P'’, ‘'R'’, ‘'S'’,
          and ‘'T'’.  The empty string is returned if no flags are set
          or if “info” contains experimental semantics.

      -- Method: set_flags (flags)

          Set the flags specified by 'flags' and unset all others.

      -- Method: add_flag (flag)

          Set the flag(s) specified by 'flag' without changing other
          flags.  To add more than one flag at a time, 'flag' may be a
          string of more than one character.  The current “info” is
          overwritten whether or not it contains experimental
          information rather than flags.

      -- Method: remove_flag (flag)

          Unset the flag(s) specified by 'flag' without changing other
          flags.  To remove more than one flag at a time, 'flag' may be
          a string of more than one character.  If “info” contains
          experimental information rather than flags, the current “info”
          is not modified.

      -- Method: get_date ()

          Return the delivery date of the message as a floating-point
          number representing seconds since the epoch.

      -- Method: set_date (date)

          Set the delivery date of the message to 'date', a
          floating-point number representing seconds since the epoch.

      -- Method: get_info ()

          Return a string containing the “info” for a message.  This is
          useful for accessing and modifying “info” that is experimental
          (i.e., not a list of flags).

      -- Method: set_info (info)

          Set “info” to 'info', which should be a string.

When a ‘MaildirMessage’ instance is created based upon an *note
mboxMessage: 378f. or *note MMDFMessage: 3926. instance, the ‘Status’
and ‘X-Status’ headers are omitted and the following conversions take
place:

Resulting state          *note mboxMessage: 378f. or
                         *note MMDFMessage: 3926. state
                         
----------------------------------------------------------------------------
                         
“cur” subdirectory       O flag
                         
                         
F flag                   F flag
                         
                         
R flag                   A flag
                         
                         
S flag                   R flag
                         
                         
T flag                   D flag
                         

When a ‘MaildirMessage’ instance is created based upon an *note
MHMessage: 390c. instance, the following conversions take place:

Resulting state                     *note MHMessage: 390c. state
                                    
-------------------------------------------------------------------
                                    
“cur” subdirectory                  “unseen” sequence
                                    
                                    
“cur” subdirectory and S flag       no “unseen” sequence
                                    
                                    
F flag                              “flagged” sequence
                                    
                                    
R flag                              “replied” sequence
                                    

When a ‘MaildirMessage’ instance is created based upon a *note
BabylMessage: 391f. instance, the following conversions take place:

Resulting state                     *note BabylMessage: 391f. state
                                    
------------------------------------------------------------------------
                                    
“cur” subdirectory                  “unseen” label
                                    
                                    
“cur” subdirectory and S flag       no “unseen” label
                                    
                                    
P flag                              “forwarded” or “resent” label
                                    
                                    
R flag                              “answered” label
                                    
                                    
T flag                              “deleted” label
                                    


File: python.info,  Node: mboxMessage objects,  Next: MHMessage objects,  Prev: MaildirMessage objects,  Up: Message objects

5.20.3.9 ‘mboxMessage’ objects
..............................

 -- Class: mailbox.mboxMessage (message=None)

     A message with mbox-specific behaviors.  Parameter 'message' has
     the same meaning as with the *note Message: 1297. constructor.

     Messages in an mbox mailbox are stored together in a single file.
     The sender’s envelope address and the time of delivery are
     typically stored in a line beginning with “From “ that is used to
     indicate the start of a message, though there is considerable
     variation in the exact format of this data among mbox
     implementations.  Flags that indicate the state of the message,
     such as whether it has been read or marked as important, are
     typically stored in ‘Status’ and ‘X-Status’ headers.

     Conventional flags for mbox messages are as follows:

     Flag       Meaning        Explanation
                               
     ---------------------------------------------------------------
                               
     R          Read           Read
                               
                               
     O          Old            Previously detected by MUA
                               
                               
     D          Deleted        Marked for subsequent deletion
                               
                               
     F          Flagged        Marked as important
                               
                               
     A          Answered       Replied to
                               

     The “R” and “O” flags are stored in the ‘Status’ header, and the
     “D”, “F”, and “A” flags are stored in the ‘X-Status’ header.  The
     flags and headers typically appear in the order mentioned.

     ‘mboxMessage’ instances offer the following methods:

      -- Method: get_from ()

          Return a string representing the “From “ line that marks the
          start of the message in an mbox mailbox.  The leading “From “
          and the trailing newline are excluded.

      -- Method: set_from (from_, time_=None)

          Set the “From “ line to 'from_', which should be specified
          without a leading “From “ or trailing newline.  For
          convenience, 'time_' may be specified and will be formatted
          appropriately and appended to 'from_'.  If 'time_' is
          specified, it should be a *note time.struct_time: d11.
          instance, a tuple suitable for passing to *note
          time.strftime(): 122e, or ‘True’ (to use *note time.gmtime():
          1205.).

      -- Method: get_flags ()

          Return a string specifying the flags that are currently set.
          If the message complies with the conventional format, the
          result is the concatenation in the following order of zero or
          one occurrence of each of ‘'R'’, ‘'O'’, ‘'D'’, ‘'F'’, and
          ‘'A'’.

      -- Method: set_flags (flags)

          Set the flags specified by 'flags' and unset all others.
          Parameter 'flags' should be the concatenation in any order of
          zero or more occurrences of each of ‘'R'’, ‘'O'’, ‘'D'’,
          ‘'F'’, and ‘'A'’.

      -- Method: add_flag (flag)

          Set the flag(s) specified by 'flag' without changing other
          flags.  To add more than one flag at a time, 'flag' may be a
          string of more than one character.

      -- Method: remove_flag (flag)

          Unset the flag(s) specified by 'flag' without changing other
          flags.  To remove more than one flag at a time, 'flag' may be
          a string of more than one character.

When an ‘mboxMessage’ instance is created based upon a *note
MaildirMessage: 38ec. instance, a “From “ line is generated based upon
the ‘MaildirMessage’ instance’s delivery date, and the following
conversions take place:

Resulting state       *note MaildirMessage: 38ec. state
                      
----------------------------------------------------------
                      
R flag                S flag
                      
                      
O flag                “cur” subdirectory
                      
                      
D flag                T flag
                      
                      
F flag                F flag
                      
                      
A flag                R flag
                      

When an ‘mboxMessage’ instance is created based upon an *note MHMessage:
390c. instance, the following conversions take place:

Resulting state         *note MHMessage: 390c. state
                        
-------------------------------------------------------
                        
R flag and O flag       no “unseen” sequence
                        
                        
O flag                  “unseen” sequence
                        
                        
F flag                  “flagged” sequence
                        
                        
A flag                  “replied” sequence
                        

When an ‘mboxMessage’ instance is created based upon a *note
BabylMessage: 391f. instance, the following conversions take place:

Resulting state         *note BabylMessage: 391f. state
                        
----------------------------------------------------------
                        
R flag and O flag       no “unseen” label
                        
                        
O flag                  “unseen” label
                        
                        
D flag                  “deleted” label
                        
                        
A flag                  “answered” label
                        

When a ‘mboxMessage’ instance is created based upon an *note
MMDFMessage: 3926. instance, the “From “ line is copied and all flags
directly correspond:

Resulting state       *note MMDFMessage: 3926. state
                      
-------------------------------------------------------
                      
R flag                R flag
                      
                      
O flag                O flag
                      
                      
D flag                D flag
                      
                      
F flag                F flag
                      
                      
A flag                A flag
                      


File: python.info,  Node: MHMessage objects,  Next: BabylMessage objects,  Prev: mboxMessage objects,  Up: Message objects

5.20.3.10 ‘MHMessage’ objects
.............................

 -- Class: mailbox.MHMessage (message=None)

     A message with MH-specific behaviors.  Parameter 'message' has the
     same meaning as with the *note Message: 1297. constructor.

     MH messages do not support marks or flags in the traditional sense,
     but they do support sequences, which are logical groupings of
     arbitrary messages.  Some mail reading programs (although not the
     standard ‘mh’ and ‘nmh’) use sequences in much the same way flags
     are used with other formats, as follows:

     Sequence       Explanation
                    
     --------------------------------------------------------------
                    
     unseen         Not read, but previously detected by MUA
                    
                    
     replied        Replied to
                    
                    
     flagged        Marked as important
                    

     ‘MHMessage’ instances offer the following methods:

      -- Method: get_sequences ()

          Return a list of the names of sequences that include this
          message.

      -- Method: set_sequences (sequences)

          Set the list of sequences that include this message.

      -- Method: add_sequence (sequence)

          Add 'sequence' to the list of sequences that include this
          message.

      -- Method: remove_sequence (sequence)

          Remove 'sequence' from the list of sequences that include this
          message.

When an ‘MHMessage’ instance is created based upon a *note
MaildirMessage: 38ec. instance, the following conversions take place:

Resulting state          *note MaildirMessage: 38ec. state
                         
-------------------------------------------------------------
                         
“unseen” sequence        no S flag
                         
                         
“replied” sequence       R flag
                         
                         
“flagged” sequence       F flag
                         

When an ‘MHMessage’ instance is created based upon an *note mboxMessage:
378f. or *note MMDFMessage: 3926. instance, the ‘Status’ and ‘X-Status’
headers are omitted and the following conversions take place:

Resulting state          *note mboxMessage: 378f. or
                         *note MMDFMessage: 3926. state
                         
----------------------------------------------------------------------------
                         
“unseen” sequence        no R flag
                         
                         
“replied” sequence       A flag
                         
                         
“flagged” sequence       F flag
                         

When an ‘MHMessage’ instance is created based upon a *note BabylMessage:
391f. instance, the following conversions take place:

Resulting state          *note BabylMessage: 391f. state
                         
-----------------------------------------------------------
                         
“unseen” sequence        “unseen” label
                         
                         
“replied” sequence       “answered” label
                         


File: python.info,  Node: BabylMessage objects,  Next: MMDFMessage objects,  Prev: MHMessage objects,  Up: Message objects

5.20.3.11 ‘BabylMessage’ objects
................................

 -- Class: mailbox.BabylMessage (message=None)

     A message with Babyl-specific behaviors.  Parameter 'message' has
     the same meaning as with the *note Message: 1297. constructor.

     Certain message labels, called 'attributes', are defined by
     convention to have special meanings.  The attributes are as
     follows:

     Label           Explanation
                     
     ---------------------------------------------------------------
                     
     unseen          Not read, but previously detected by MUA
                     
                     
     deleted         Marked for subsequent deletion
                     
                     
     filed           Copied to another file or mailbox
                     
                     
     answered        Replied to
                     
                     
     forwarded       Forwarded
                     
                     
     edited          Modified by the user
                     
                     
     resent          Resent
                     

     By default, Rmail displays only visible headers.  The
     ‘BabylMessage’ class, though, uses the original headers because
     they are more complete.  Visible headers may be accessed explicitly
     if desired.

     ‘BabylMessage’ instances offer the following methods:

      -- Method: get_labels ()

          Return a list of labels on the message.

      -- Method: set_labels (labels)

          Set the list of labels on the message to 'labels'.

      -- Method: add_label (label)

          Add 'label' to the list of labels on the message.

      -- Method: remove_label (label)

          Remove 'label' from the list of labels on the message.

      -- Method: get_visible ()

          Return a *note Message: 1297. instance whose headers are the
          message’s visible headers and whose body is empty.

      -- Method: set_visible (visible)

          Set the message’s visible headers to be the same as the
          headers in 'message'.  Parameter 'visible' should be a *note
          Message: 1297. instance, an *note email.message.Message: 27c.
          instance, a string, or a file-like object (which should be
          open in text mode).

      -- Method: update_visible ()

          When a ‘BabylMessage’ instance’s original headers are
          modified, the visible headers are not automatically modified
          to correspond.  This method updates the visible headers as
          follows: each visible header with a corresponding original
          header is set to the value of the original header, each
          visible header without a corresponding original header is
          removed, and any of ‘Date’, ‘From’, ‘Reply-To’, ‘To’, ‘CC’,
          and ‘Subject’ that are present in the original headers but not
          the visible headers are added to the visible headers.

When a ‘BabylMessage’ instance is created based upon a *note
MaildirMessage: 38ec. instance, the following conversions take place:

Resulting state         *note MaildirMessage: 38ec. state
                        
------------------------------------------------------------
                        
“unseen” label          no S flag
                        
                        
“deleted” label         T flag
                        
                        
“answered” label        R flag
                        
                        
“forwarded” label       P flag
                        

When a ‘BabylMessage’ instance is created based upon an *note
mboxMessage: 378f. or *note MMDFMessage: 3926. instance, the ‘Status’
and ‘X-Status’ headers are omitted and the following conversions take
place:

Resulting state        *note mboxMessage: 378f. or
                       *note MMDFMessage: 3926. state
                       
--------------------------------------------------------------------------
                       
“unseen” label         no R flag
                       
                       
“deleted” label        D flag
                       
                       
“answered” label       A flag
                       

When a ‘BabylMessage’ instance is created based upon an *note MHMessage:
390c. instance, the following conversions take place:

Resulting state        *note MHMessage: 390c. state
                       
------------------------------------------------------
                       
“unseen” label         “unseen” sequence
                       
                       
“answered” label       “replied” sequence
                       


File: python.info,  Node: MMDFMessage objects,  Prev: BabylMessage objects,  Up: Message objects

5.20.3.12 ‘MMDFMessage’ objects
...............................

 -- Class: mailbox.MMDFMessage (message=None)

     A message with MMDF-specific behaviors.  Parameter 'message' has
     the same meaning as with the *note Message: 1297. constructor.

     As with message in an mbox mailbox, MMDF messages are stored with
     the sender’s address and the delivery date in an initial line
     beginning with “From “.  Likewise, flags that indicate the state of
     the message are typically stored in ‘Status’ and ‘X-Status’
     headers.

     Conventional flags for MMDF messages are identical to those of mbox
     message and are as follows:

     Flag       Meaning        Explanation
                               
     ---------------------------------------------------------------
                               
     R          Read           Read
                               
                               
     O          Old            Previously detected by MUA
                               
                               
     D          Deleted        Marked for subsequent deletion
                               
                               
     F          Flagged        Marked as important
                               
                               
     A          Answered       Replied to
                               

     The “R” and “O” flags are stored in the ‘Status’ header, and the
     “D”, “F”, and “A” flags are stored in the ‘X-Status’ header.  The
     flags and headers typically appear in the order mentioned.

     ‘MMDFMessage’ instances offer the following methods, which are
     identical to those offered by *note mboxMessage: 378f.:

      -- Method: get_from ()

          Return a string representing the “From “ line that marks the
          start of the message in an mbox mailbox.  The leading “From “
          and the trailing newline are excluded.

      -- Method: set_from (from_, time_=None)

          Set the “From “ line to 'from_', which should be specified
          without a leading “From “ or trailing newline.  For
          convenience, 'time_' may be specified and will be formatted
          appropriately and appended to 'from_'.  If 'time_' is
          specified, it should be a *note time.struct_time: d11.
          instance, a tuple suitable for passing to *note
          time.strftime(): 122e, or ‘True’ (to use *note time.gmtime():
          1205.).

      -- Method: get_flags ()

          Return a string specifying the flags that are currently set.
          If the message complies with the conventional format, the
          result is the concatenation in the following order of zero or
          one occurrence of each of ‘'R'’, ‘'O'’, ‘'D'’, ‘'F'’, and
          ‘'A'’.

      -- Method: set_flags (flags)

          Set the flags specified by 'flags' and unset all others.
          Parameter 'flags' should be the concatenation in any order of
          zero or more occurrences of each of ‘'R'’, ‘'O'’, ‘'D'’,
          ‘'F'’, and ‘'A'’.

      -- Method: add_flag (flag)

          Set the flag(s) specified by 'flag' without changing other
          flags.  To add more than one flag at a time, 'flag' may be a
          string of more than one character.

      -- Method: remove_flag (flag)

          Unset the flag(s) specified by 'flag' without changing other
          flags.  To remove more than one flag at a time, 'flag' may be
          a string of more than one character.

When an ‘MMDFMessage’ instance is created based upon a *note
MaildirMessage: 38ec. instance, a “From “ line is generated based upon
the ‘MaildirMessage’ instance’s delivery date, and the following
conversions take place:

Resulting state       *note MaildirMessage: 38ec. state
                      
----------------------------------------------------------
                      
R flag                S flag
                      
                      
O flag                “cur” subdirectory
                      
                      
D flag                T flag
                      
                      
F flag                F flag
                      
                      
A flag                R flag
                      

When an ‘MMDFMessage’ instance is created based upon an *note MHMessage:
390c. instance, the following conversions take place:

Resulting state         *note MHMessage: 390c. state
                        
-------------------------------------------------------
                        
R flag and O flag       no “unseen” sequence
                        
                        
O flag                  “unseen” sequence
                        
                        
F flag                  “flagged” sequence
                        
                        
A flag                  “replied” sequence
                        

When an ‘MMDFMessage’ instance is created based upon a *note
BabylMessage: 391f. instance, the following conversions take place:

Resulting state         *note BabylMessage: 391f. state
                        
----------------------------------------------------------
                        
R flag and O flag       no “unseen” label
                        
                        
O flag                  “unseen” label
                        
                        
D flag                  “deleted” label
                        
                        
A flag                  “answered” label
                        

When an ‘MMDFMessage’ instance is created based upon an *note
mboxMessage: 378f. instance, the “From “ line is copied and all flags
directly correspond:

Resulting state       *note mboxMessage: 378f. state
                      
-------------------------------------------------------
                      
R flag                R flag
                      
                      
O flag                O flag
                      
                      
D flag                D flag
                      
                      
F flag                F flag
                      
                      
A flag                A flag
                      


File: python.info,  Node: Exceptions<18>,  Next: Examples<23>,  Prev: Message objects,  Up: mailbox — Manipulate mailboxes in various formats

5.20.3.13 Exceptions
....................

The following exception classes are defined in the ‘mailbox’ module:

 -- Exception: mailbox.Error

     The base class for all other module-specific exceptions.

 -- Exception: mailbox.NoSuchMailboxError

     Raised when a mailbox is expected but is not found, such as when
     instantiating a *note Mailbox: 1293. subclass with a path that does
     not exist (and with the 'create' parameter set to ‘False’), or when
     opening a folder that does not exist.

 -- Exception: mailbox.NotEmptyError

     Raised when a mailbox is not empty but is expected to be, such as
     when deleting a folder that contains messages.

 -- Exception: mailbox.ExternalClashError

     Raised when some mailbox-related condition beyond the control of
     the program causes it to be unable to proceed, such as when failing
     to acquire a lock that another program already holds, or when a
     uniquely generated file name already exists.

 -- Exception: mailbox.FormatError

     Raised when the data in a file cannot be parsed, such as when an
     *note MH: 17c6. instance attempts to read a corrupted
     ‘.mh_sequences’ file.


File: python.info,  Node: Examples<23>,  Prev: Exceptions<18>,  Up: mailbox — Manipulate mailboxes in various formats

5.20.3.14 Examples
..................

A simple example of printing the subjects of all messages in a mailbox
that seem interesting:

     import mailbox
     for message in mailbox.mbox('~/mbox'):
         subject = message['subject']       # Could possibly be None.
         if subject and 'python' in subject.lower():
             print(subject)

To copy all mail from a Babyl mailbox to an MH mailbox, converting all
of the format-specific information that can be converted:

     import mailbox
     destination = mailbox.MH('~/Mail')
     destination.lock()
     for message in mailbox.Babyl('~/RMAIL'):
         destination.add(mailbox.MHMessage(message))
     destination.flush()
     destination.unlock()

This example sorts mail from several mailing lists into different
mailboxes, being careful to avoid mail corruption due to concurrent
modification by other programs, mail loss due to interruption of the
program, or premature termination due to malformed messages in the
mailbox:

     import mailbox
     import email.errors

     list_names = ('python-list', 'python-dev', 'python-bugs')

     boxes = {name: mailbox.mbox('~/email/%s' % name) for name in list_names}
     inbox = mailbox.Maildir('~/Maildir', factory=None)

     for key in inbox.iterkeys():
         try:
             message = inbox[key]
         except email.errors.MessageParseError:
             continue                # The message is malformed. Just leave it.

         for name in list_names:
             list_id = message['list-id']
             if list_id and name in list_id:
                 # Get mailbox to use
                 box = boxes[name]

                 # Write copy to disk before removing original.
                 # If there's a crash, you might duplicate a message, but
                 # that's better than losing a message completely.
                 box.lock()
                 box.add(message)
                 box.flush()
                 box.unlock()

                 # Remove original message
                 inbox.lock()
                 inbox.discard(key)
                 inbox.flush()
                 inbox.unlock()
                 break               # Found destination, so stop looking.

     for box in boxes.itervalues():
         box.close()


File: python.info,  Node: mimetypes — Map filenames to MIME types,  Next: base64 — Base16 Base32 Base64 Base85 Data Encodings,  Prev: mailbox — Manipulate mailboxes in various formats,  Up: Internet Data Handling

5.20.4 ‘mimetypes’ — Map filenames to MIME types
------------------------------------------------

'Source code:' Lib/mimetypes.py(1)

__________________________________________________________________

The ‘mimetypes’ module converts between a filename or URL and the MIME
type associated with the filename extension.  Conversions are provided
from filename to MIME type and from MIME type to filename extension;
encodings are not supported for the latter conversion.

The module provides one class and a number of convenience functions.
The functions are the normal interface to this module, but some
applications may be interested in the class as well.

The functions described below provide the primary interface for this
module.  If the module has not been initialized, they will call *note
init(): 395a. if they rely on the information ‘init()’ sets up.

 -- Function: mimetypes.guess_type (url, strict=True)

     Guess the type of a file based on its filename, path or URL, given
     by 'url'.  URL can be a string or a *note path-like object: 2a0.

     The return value is a tuple ‘(type, encoding)’ where 'type' is
     ‘None’ if the type can’t be guessed (missing or unknown suffix) or
     a string of the form ‘'type/subtype'’, usable for a MIME
     ‘content-type’ header.

     'encoding' is ‘None’ for no encoding or the name of the program
     used to encode (e.g.  ‘compress’ or ‘gzip’).  The encoding is
     suitable for use as a ‘Content-Encoding’ header, 'not' as a
     ‘Content-Transfer-Encoding’ header.  The mappings are table driven.
     Encoding suffixes are case sensitive; type suffixes are first tried
     case sensitively, then case insensitively.

     The optional 'strict' argument is a flag specifying whether the
     list of known MIME types is limited to only the official types
     registered with IANA(2). When 'strict' is ‘True’ (the default),
     only the IANA types are supported; when 'strict' is ‘False’, some
     additional non-standard but commonly used MIME types are also
     recognized.

     Changed in version 3.8: Added support for 'url' being a *note
     path-like object: 2a0.

     Deprecated since version 3.13: Passing a file path instead of URL
     is *note soft deprecated: 209.  Use *note guess_file_type(): 207.
     for this.

 -- Function: mimetypes.guess_file_type (path, *, strict=True)

     Guess the type of a file based on its path, given by 'path'.
     Similar to the *note guess_type(): 208. function, but accepts a
     path instead of URL. Path can be a string, a bytes object or a
     *note path-like object: 2a0.

     Added in version 3.13.

 -- Function: mimetypes.guess_all_extensions (type, strict=True)

     Guess the extensions for a file based on its MIME type, given by
     'type'.  The return value is a list of strings giving all possible
     filename extensions, including the leading dot (‘'.'’).  The
     extensions are not guaranteed to have been associated with any
     particular data stream, but would be mapped to the MIME type 'type'
     by *note guess_type(): 208. and *note guess_file_type(): 207.

     The optional 'strict' argument has the same meaning as with the
     *note guess_type(): 208. function.

 -- Function: mimetypes.guess_extension (type, strict=True)

     Guess the extension for a file based on its MIME type, given by
     'type'.  The return value is a string giving a filename extension,
     including the leading dot (‘'.'’).  The extension is not guaranteed
     to have been associated with any particular data stream, but would
     be mapped to the MIME type 'type' by *note guess_type(): 208. and
     *note guess_file_type(): 207.  If no extension can be guessed for
     'type', ‘None’ is returned.

     The optional 'strict' argument has the same meaning as with the
     *note guess_type(): 208. function.

Some additional functions and data items are available for controlling
the behavior of the module.

 -- Function: mimetypes.init (files=None)

     Initialize the internal data structures.  If given, 'files' must be
     a sequence of file names which should be used to augment the
     default type map.  If omitted, the file names to use are taken from
     *note knownfiles: 395c.; on Windows, the current registry settings
     are loaded.  Each file named in 'files' or ‘knownfiles’ takes
     precedence over those named before it.  Calling ‘init()’ repeatedly
     is allowed.

     Specifying an empty list for 'files' will prevent the system
     defaults from being applied: only the well-known values will be
     present from a built-in list.

     If 'files' is ‘None’ the internal data structure is completely
     rebuilt to its initial default value.  This is a stable operation
     and will produce the same results when called multiple times.

     Changed in version 3.2: Previously, Windows registry settings were
     ignored.

 -- Function: mimetypes.read_mime_types (filename)

     Load the type map given in the file 'filename', if it exists.  The
     type map is returned as a dictionary mapping filename extensions,
     including the leading dot (‘'.'’), to strings of the form
     ‘'type/subtype'’.  If the file 'filename' does not exist or cannot
     be read, ‘None’ is returned.

 -- Function: mimetypes.add_type (type, ext, strict=True)

     Add a mapping from the MIME type 'type' to the extension 'ext'.
     When the extension is already known, the new type will replace the
     old one.  When the type is already known the extension will be
     added to the list of known extensions.

     When 'strict' is ‘True’ (the default), the mapping will be added to
     the official MIME types, otherwise to the non-standard ones.

 -- Data: mimetypes.inited

     Flag indicating whether or not the global data structures have been
     initialized.  This is set to ‘True’ by *note init(): 395a.

 -- Data: mimetypes.knownfiles

     List of type map file names commonly installed.  These files are
     typically named ‘mime.types’ and are installed in different
     locations by different packages.

 -- Data: mimetypes.suffix_map

     Dictionary mapping suffixes to suffixes.  This is used to allow
     recognition of encoded files for which the encoding and the type
     are indicated by the same extension.  For example, the ‘.tgz’
     extension is mapped to ‘.tar.gz’ to allow the encoding and type to
     be recognized separately.

 -- Data: mimetypes.encodings_map

     Dictionary mapping filename extensions to encoding types.

 -- Data: mimetypes.types_map

     Dictionary mapping filename extensions to MIME types.

 -- Data: mimetypes.common_types

     Dictionary mapping filename extensions to non-standard, but
     commonly found MIME types.

An example usage of the module:

     >>> import mimetypes
     >>> mimetypes.init()
     >>> mimetypes.knownfiles
     ['/etc/mime.types', '/etc/httpd/mime.types', ... ]
     >>> mimetypes.suffix_map['.tgz']
     '.tar.gz'
     >>> mimetypes.encodings_map['.gz']
     'gzip'
     >>> mimetypes.types_map['.tgz']
     'application/x-tar-gz'

* Menu:

* MimeTypes Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/mimetypes.py

   (2) https://www.iana.org/assignments/media-types/media-types.xhtml


File: python.info,  Node: MimeTypes Objects,  Up: mimetypes — Map filenames to MIME types

5.20.4.1 MimeTypes Objects
..........................

The *note MimeTypes: 154a. class may be useful for applications which
may want more than one MIME-type database; it provides an interface
similar to the one of the ‘mimetypes’ module.

 -- Class: mimetypes.MimeTypes (filenames=(), strict=True)

     This class represents a MIME-types database.  By default, it
     provides access to the same database as the rest of this module.
     The initial database is a copy of that provided by the module, and
     may be extended by loading additional ‘mime.types’-style files into
     the database using the *note read(): 3965. or *note readfp(): 3966.
     methods.  The mapping dictionaries may also be cleared before
     loading additional data if the default data is not desired.

     The optional 'filenames' parameter can be used to cause additional
     files to be loaded “on top” of the default database.

      -- Attribute: suffix_map

          Dictionary mapping suffixes to suffixes.  This is used to
          allow recognition of encoded files for which the encoding and
          the type are indicated by the same extension.  For example,
          the ‘.tgz’ extension is mapped to ‘.tar.gz’ to allow the
          encoding and type to be recognized separately.  This is
          initially a copy of the global *note suffix_map: 395f. defined
          in the module.

      -- Attribute: encodings_map

          Dictionary mapping filename extensions to encoding types.
          This is initially a copy of the global *note encodings_map:
          3960. defined in the module.

      -- Attribute: types_map

          Tuple containing two dictionaries, mapping filename extensions
          to MIME types: the first dictionary is for the non-standards
          types and the second one is for the standard types.  They are
          initialized by *note common_types: 3962. and *note types_map:
          3961.

      -- Attribute: types_map_inv

          Tuple containing two dictionaries, mapping MIME types to a
          list of filename extensions: the first dictionary is for the
          non-standards types and the second one is for the standard
          types.  They are initialized by *note common_types: 3962. and
          *note types_map: 3961.

      -- Method: guess_extension (type, strict=True)

          Similar to the *note guess_extension(): 395b. function, using
          the tables stored as part of the object.

      -- Method: guess_type (url, strict=True)

          Similar to the *note guess_type(): 208. function, using the
          tables stored as part of the object.

      -- Method: guess_file_type (path, *, strict=True)

          Similar to the *note guess_file_type(): 207. function, using
          the tables stored as part of the object.

          Added in version 3.13.

      -- Method: guess_all_extensions (type, strict=True)

          Similar to the *note guess_all_extensions(): 19f0. function,
          using the tables stored as part of the object.

      -- Method: read (filename, strict=True)

          Load MIME information from a file named 'filename'.  This uses
          *note readfp(): 3966. to parse the file.

          If 'strict' is ‘True’, information will be added to list of
          standard types, else to the list of non-standard types.

      -- Method: readfp (fp, strict=True)

          Load MIME type information from an open file 'fp'.  The file
          must have the format of the standard ‘mime.types’ files.

          If 'strict' is ‘True’, information will be added to the list
          of standard types, else to the list of non-standard types.

      -- Method: read_windows_registry (strict=True)

          Load MIME type information from the Windows registry.

          *note Availability: 1ef7.: Windows.

          If 'strict' is ‘True’, information will be added to the list
          of standard types, else to the list of non-standard types.

          Added in version 3.2.

      -- Method: add_type (type, ext, strict=True)

          Add a mapping from the MIME type 'type' to the extension
          'ext'.  When the extension is already known, the new type will
          replace the old one.  When the type is already known the
          extension will be added to the list of known extensions.

          When 'strict' is ‘True’ (the default), the mapping will be
          added to the official MIME types, otherwise to the
          non-standard ones.


File: python.info,  Node: base64 — Base16 Base32 Base64 Base85 Data Encodings,  Next: binascii — Convert between binary and ASCII,  Prev: mimetypes — Map filenames to MIME types,  Up: Internet Data Handling

5.20.5 ‘base64’ — Base16, Base32, Base64, Base85 Data Encodings
---------------------------------------------------------------

'Source code:' Lib/base64.py(1)

__________________________________________________________________

This module provides functions for encoding binary data to printable
ASCII characters and decoding such encodings back to binary data.  This
includes the *note encodings specified in: 3973. RFC 4648(2) (Base64,
Base32 and Base16) and the non-standard *note Base85 encodings: 3974.

There are two interfaces provided by this module.  The modern interface
supports encoding *note bytes-like objects: d55. to ASCII *note bytes:
1c2, and decoding bytes-like objects or strings containing ASCII to
‘bytes’.  Both base-64 alphabets defined in RFC 4648(3) (normal, and
URL- and filesystem-safe) are supported.

The *note legacy interface: 3975. does not support decoding from
strings, but it does provide functions for encoding and decoding to and
from *note file objects: 1208.  It only supports the Base64 standard
alphabet, and it adds newlines every 76 characters as per RFC 2045(4).
Note that if you are looking for RFC 2045(5) support you probably want
to be looking at the *note email: 3b. package instead.

Changed in version 3.3: ASCII-only Unicode strings are now accepted by
the decoding functions of the modern interface.

Changed in version 3.4: Any *note bytes-like objects: d55. are now
accepted by all encoding and decoding functions in this module.
Ascii85/Base85 support added.

* Menu:

* RFC 4648 Encodings::
* Base85 Encodings::
* Legacy Interface::
* Security Considerations: Security Considerations<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/base64.py

   (2) https://datatracker.ietf.org/doc/html/rfc4648.html

   (3) https://datatracker.ietf.org/doc/html/rfc4648.html

   (4) https://datatracker.ietf.org/doc/html/rfc2045.html

   (5) https://datatracker.ietf.org/doc/html/rfc2045.html


File: python.info,  Node: RFC 4648 Encodings,  Next: Base85 Encodings,  Up: base64 — Base16 Base32 Base64 Base85 Data Encodings

5.20.5.1 RFC 4648 Encodings
...........................

The RFC 4648(1) encodings are suitable for encoding binary data so that
it can be safely sent by email, used as parts of URLs, or included as
part of an HTTP POST request.

 -- Function: base64.b64encode (s, altchars=None)

     Encode the *note bytes-like object: d55. 's' using Base64 and
     return the encoded *note bytes: 1c2.

     Optional 'altchars' must be a *note bytes-like object: d55. of
     length 2 which specifies an alternative alphabet for the ‘+’ and
     ‘/’ characters.  This allows an application to e.g.  generate URL
     or filesystem safe Base64 strings.  The default is ‘None’, for
     which the standard Base64 alphabet is used.

     May assert or raise a *note ValueError: 202. if the length of
     'altchars' is not 2.  Raises a *note TypeError: 2c3. if 'altchars'
     is not a *note bytes-like object: d55.

 -- Function: base64.b64decode (s, altchars=None, validate=False)

     Decode the Base64 encoded *note bytes-like object: d55. or ASCII
     string 's' and return the decoded *note bytes: 1c2.

     Optional 'altchars' must be a *note bytes-like object: d55. or
     ASCII string of length 2 which specifies the alternative alphabet
     used instead of the ‘+’ and ‘/’ characters.

     A *note binascii.Error: 1061. exception is raised if 's' is
     incorrectly padded.

     If 'validate' is ‘False’ (the default), characters that are neither
     in the normal base-64 alphabet nor the alternative alphabet are
     discarded prior to the padding check.  If 'validate' is ‘True’,
     these non-alphabet characters in the input result in a *note
     binascii.Error: 1061.

     For more information about the strict base64 check, see *note
     binascii.a2b_base64(): 15ae.

     May assert or raise a *note ValueError: 202. if the length of
     'altchars' is not 2.

 -- Function: base64.standard_b64encode (s)

     Encode *note bytes-like object: d55. 's' using the standard Base64
     alphabet and return the encoded *note bytes: 1c2.

 -- Function: base64.standard_b64decode (s)

     Decode *note bytes-like object: d55. or ASCII string 's' using the
     standard Base64 alphabet and return the decoded *note bytes: 1c2.

 -- Function: base64.urlsafe_b64encode (s)

     Encode *note bytes-like object: d55. 's' using the URL- and
     filesystem-safe alphabet, which substitutes ‘-’ instead of ‘+’ and
     ‘_’ instead of ‘/’ in the standard Base64 alphabet, and return the
     encoded *note bytes: 1c2.  The result can still contain ‘=’.

 -- Function: base64.urlsafe_b64decode (s)

     Decode *note bytes-like object: d55. or ASCII string 's' using the
     URL- and filesystem-safe alphabet, which substitutes ‘-’ instead of
     ‘+’ and ‘_’ instead of ‘/’ in the standard Base64 alphabet, and
     return the decoded *note bytes: 1c2.

 -- Function: base64.b32encode (s)

     Encode the *note bytes-like object: d55. 's' using Base32 and
     return the encoded *note bytes: 1c2.

 -- Function: base64.b32decode (s, casefold=False, map01=None)

     Decode the Base32 encoded *note bytes-like object: d55. or ASCII
     string 's' and return the decoded *note bytes: 1c2.

     Optional 'casefold' is a flag specifying whether a lowercase
     alphabet is acceptable as input.  For security purposes, the
     default is ‘False’.

     RFC 4648(2) allows for optional mapping of the digit 0 (zero) to
     the letter O (oh), and for optional mapping of the digit 1 (one) to
     either the letter I (eye) or letter L (el).  The optional argument
     'map01' when not ‘None’, specifies which letter the digit 1 should
     be mapped to (when 'map01' is not ‘None’, the digit 0 is always
     mapped to the letter O). For security purposes the default is
     ‘None’, so that 0 and 1 are not allowed in the input.

     A *note binascii.Error: 1061. is raised if 's' is incorrectly
     padded or if there are non-alphabet characters present in the
     input.

 -- Function: base64.b32hexencode (s)

     Similar to *note b32encode(): 397c. but uses the Extended Hex
     Alphabet, as defined in RFC 4648(3).

     Added in version 3.10.

 -- Function: base64.b32hexdecode (s, casefold=False)

     Similar to *note b32decode(): 1060. but uses the Extended Hex
     Alphabet, as defined in RFC 4648(4).

     This version does not allow the digit 0 (zero) to the letter O (oh)
     and digit 1 (one) to either the letter I (eye) or letter L (el)
     mappings, all these characters are included in the Extended Hex
     Alphabet and are not interchangeable.

     Added in version 3.10.

 -- Function: base64.b16encode (s)

     Encode the *note bytes-like object: d55. 's' using Base16 and
     return the encoded *note bytes: 1c2.

 -- Function: base64.b16decode (s, casefold=False)

     Decode the Base16 encoded *note bytes-like object: d55. or ASCII
     string 's' and return the decoded *note bytes: 1c2.

     Optional 'casefold' is a flag specifying whether a lowercase
     alphabet is acceptable as input.  For security purposes, the
     default is ‘False’.

     A *note binascii.Error: 1061. is raised if 's' is incorrectly
     padded or if there are non-alphabet characters present in the
     input.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc4648.html

   (2) https://datatracker.ietf.org/doc/html/rfc4648.html

   (3) https://datatracker.ietf.org/doc/html/rfc4648.html

   (4) https://datatracker.ietf.org/doc/html/rfc4648.html


File: python.info,  Node: Base85 Encodings,  Next: Legacy Interface,  Prev: RFC 4648 Encodings,  Up: base64 — Base16 Base32 Base64 Base85 Data Encodings

5.20.5.2 Base85 Encodings
.........................

Base85 encoding is not formally specified but rather a de facto
standard, thus different systems perform the encoding differently.

The *note a85encode(): f55. and *note b85encode(): f57. functions in
this module are two implementations of the de facto standard.  You
should call the function with the Base85 implementation used by the
software you intend to work with.

The two functions present in this module differ in how they handle the
following:

   * Whether to include enclosing ‘<~’ and ‘~>’ markers

   * Whether to include newline characters

   * The set of ASCII characters used for encoding

   * Handling of null bytes

Refer to the documentation of the individual functions for more
information.

 -- Function: base64.a85encode (b, *, foldspaces=False, wrapcol=0,
          pad=False, adobe=False)

     Encode the *note bytes-like object: d55. 'b' using Ascii85 and
     return the encoded *note bytes: 1c2.

     'foldspaces' is an optional flag that uses the special short
     sequence ‘y’ instead of 4 consecutive spaces (ASCII 0x20) as
     supported by ‘btoa’.  This feature is not supported by the
     “standard” Ascii85 encoding.

     'wrapcol' controls whether the output should have newline (‘b'\n'’)
     characters added to it.  If this is non-zero, each output line will
     be at most this many characters long, excluding the trailing
     newline.

     'pad' controls whether the input is padded to a multiple of 4
     before encoding.  Note that the ‘btoa’ implementation always pads.

     'adobe' controls whether the encoded byte sequence is framed with
     ‘<~’ and ‘~>’, which is used by the Adobe implementation.

     Added in version 3.4.

 -- Function: base64.a85decode (b, *, foldspaces=False, adobe=False,
          ignorechars=b' \t\n\r\x0b')

     Decode the Ascii85 encoded *note bytes-like object: d55. or ASCII
     string 'b' and return the decoded *note bytes: 1c2.

     'foldspaces' is a flag that specifies whether the ‘y’ short
     sequence should be accepted as shorthand for 4 consecutive spaces
     (ASCII 0x20).  This feature is not supported by the “standard”
     Ascii85 encoding.

     'adobe' controls whether the input sequence is in Adobe Ascii85
     format (i.e.  is framed with <~ and ~>).

     'ignorechars' should be a byte string containing characters to
     ignore from the input.  This should only contain whitespace
     characters, and by default contains all whitespace characters in
     ASCII.

     Added in version 3.4.

 -- Function: base64.b85encode (b, pad=False)

     Encode the *note bytes-like object: d55. 'b' using base85 (as used
     in e.g.  git-style binary diffs) and return the encoded *note
     bytes: 1c2.

     If 'pad' is true, the input is padded with ‘b'\0'’ so its length is
     a multiple of 4 bytes before encoding.

     Added in version 3.4.

 -- Function: base64.b85decode (b)

     Decode the base85-encoded *note bytes-like object: d55. or ASCII
     string 'b' and return the decoded *note bytes: 1c2.  Padding is
     implicitly removed, if necessary.

     Added in version 3.4.

 -- Function: base64.z85encode (s)

     Encode the *note bytes-like object: d55. 's' using Z85 (as used in
     ZeroMQ) and return the encoded *note bytes: 1c2.  See Z85
     specification(1) for more information.

     Added in version 3.13.

 -- Function: base64.z85decode (s)

     Decode the Z85-encoded *note bytes-like object: d55. or ASCII
     string 's' and return the decoded *note bytes: 1c2.  See Z85
     specification(2) for more information.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://rfc.zeromq.org/spec/32/

   (2) https://rfc.zeromq.org/spec/32/


File: python.info,  Node: Legacy Interface,  Next: Security Considerations<2>,  Prev: Base85 Encodings,  Up: base64 — Base16 Base32 Base64 Base85 Data Encodings

5.20.5.3 Legacy Interface
.........................

 -- Function: base64.decode (input, output)

     Decode the contents of the binary 'input' file and write the
     resulting binary data to the 'output' file.  'input' and 'output'
     must be *note file objects: 1208.  'input' will be read until
     ‘input.readline()’ returns an empty bytes object.

 -- Function: base64.decodebytes (s)

     Decode the *note bytes-like object: d55. 's', which must contain
     one or more lines of base64 encoded data, and return the decoded
     *note bytes: 1c2.

     Added in version 3.1.

 -- Function: base64.encode (input, output)

     Encode the contents of the binary 'input' file and write the
     resulting base64 encoded data to the 'output' file.  'input' and
     'output' must be *note file objects: 1208.  'input' will be read
     until ‘input.read()’ returns an empty bytes object.  ‘encode()’
     inserts a newline character (‘b'\n'’) after every 76 bytes of the
     output, as well as ensuring that the output always ends with a
     newline, as per RFC 2045(1) (MIME).

 -- Function: base64.encodebytes (s)

     Encode the *note bytes-like object: d55. 's', which can contain
     arbitrary binary data, and return *note bytes: 1c2. containing the
     base64-encoded data, with newlines (‘b'\n'’) inserted after every
     76 bytes of output, and ensuring that there is a trailing newline,
     as per RFC 2045(2) (MIME).

     Added in version 3.1.

An example usage of the module:

     >>> import base64
     >>> encoded = base64.b64encode(b'data to be encoded')
     >>> encoded
     b'ZGF0YSB0byBiZSBlbmNvZGVk'
     >>> data = base64.b64decode(encoded)
     >>> data
     b'data to be encoded'

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2045.html

   (2) https://datatracker.ietf.org/doc/html/rfc2045.html


File: python.info,  Node: Security Considerations<2>,  Prev: Legacy Interface,  Up: base64 — Base16 Base32 Base64 Base85 Data Encodings

5.20.5.4 Security Considerations
................................

A new security considerations section was added to RFC 4648(1) (section
12); it’s recommended to review the security section for any code
deployed to production.

See also
........

Module *note binascii: 10.

     Support module containing ASCII-to-binary and binary-to-ASCII
     conversions.

RFC 1521(2) - MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies

     Section 5.2, “Base64 Content-Transfer-Encoding,” provides the
     definition of the base64 encoding.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc4648.html

   (2) https://datatracker.ietf.org/doc/html/rfc1521.html


File: python.info,  Node: binascii — Convert between binary and ASCII,  Next: quopri — Encode and decode MIME quoted-printable data,  Prev: base64 — Base16 Base32 Base64 Base85 Data Encodings,  Up: Internet Data Handling

5.20.6 ‘binascii’ — Convert between binary and ASCII
----------------------------------------------------

__________________________________________________________________

The ‘binascii’ module contains a number of methods to convert between
binary and various ASCII-encoded binary representations.  Normally, you
will not use these functions directly but use wrapper modules like *note
base64: e. instead.  The ‘binascii’ module contains low-level functions
written in C for greater speed that are used by the higher-level
modules.

     Note: ‘a2b_*’ functions accept Unicode strings containing only
     ASCII characters.  Other functions only accept *note bytes-like
     objects: d55. (such as *note bytes: 1c2, *note bytearray: 2ea. and
     other objects that support the buffer protocol).

     Changed in version 3.3: ASCII-only unicode strings are now accepted
     by the ‘a2b_*’ functions.

The ‘binascii’ module defines the following functions:

 -- Function: binascii.a2b_uu (string)

     Convert a single line of uuencoded data back to binary and return
     the binary data.  Lines normally contain 45 (binary) bytes, except
     for the last line.  Line data may be followed by whitespace.

 -- Function: binascii.b2a_uu (data, *, backtick=False)

     Convert binary data to a line of ASCII characters, the return value
     is the converted line, including a newline char.  The length of
     'data' should be at most 45.  If 'backtick' is true, zeros are
     represented by ‘'`'’ instead of spaces.

     Changed in version 3.7: Added the 'backtick' parameter.

 -- Function: binascii.a2b_base64 (string, /, *, strict_mode=False)

     Convert a block of base64 data back to binary and return the binary
     data.  More than one line may be passed at a time.

     If 'strict_mode' is true, only valid base64 data will be converted.
     Invalid base64 data will raise *note binascii.Error: 1061.

     Valid base64:

        * Conforms to RFC 3548(1).

        * Contains only characters from the base64 alphabet.

        * Contains no excess data after padding (including excess
          padding, newlines, etc.).

        * Does not start with a padding.

     Changed in version 3.11: Added the 'strict_mode' parameter.

 -- Function: binascii.b2a_base64 (data, *, newline=True)

     Convert binary data to a line of ASCII characters in base64 coding.
     The return value is the converted line, including a newline char if
     'newline' is true.  The output of this function conforms to RFC
     3548(2).

     Changed in version 3.6: Added the 'newline' parameter.

 -- Function: binascii.a2b_qp (data, header=False)

     Convert a block of quoted-printable data back to binary and return
     the binary data.  More than one line may be passed at a time.  If
     the optional argument 'header' is present and true, underscores
     will be decoded as spaces.

 -- Function: binascii.b2a_qp (data, quotetabs=False, istext=True,
          header=False)

     Convert binary data to a line(s) of ASCII characters in
     quoted-printable encoding.  The return value is the converted
     line(s).  If the optional argument 'quotetabs' is present and true,
     all tabs and spaces will be encoded.  If the optional argument
     'istext' is present and true, newlines are not encoded but trailing
     whitespace will be encoded.  If the optional argument 'header' is
     present and true, spaces will be encoded as underscores per RFC
     1522(3).  If the optional argument 'header' is present and false,
     newline characters will be encoded as well; otherwise linefeed
     conversion might corrupt the binary data stream.

 -- Function: binascii.crc_hqx (data, value)

     Compute a 16-bit CRC value of 'data', starting with 'value' as the
     initial CRC, and return the result.  This uses the CRC-CCITT
     polynomial 'x'^16 + 'x'^12 + 'x'^5 + 1, often represented as
     0x1021.  This CRC is used in the binhex4 format.

 -- Function: binascii.crc32 (data[, value])

     Compute CRC-32, the unsigned 32-bit checksum of 'data', starting
     with an initial CRC of 'value'.  The default initial CRC is zero.
     The algorithm is consistent with the ZIP file checksum.  Since the
     algorithm is designed for use as a checksum algorithm, it is not
     suitable for use as a general hash algorithm.  Use as follows:

          print(binascii.crc32(b"hello world"))
          # Or, in two pieces:
          crc = binascii.crc32(b"hello")
          crc = binascii.crc32(b" world", crc)
          print('crc32 = {:#010x}'.format(crc))

     Changed in version 3.0: The result is always unsigned.

 -- Function: binascii.b2a_hex (data[, sep[, bytes_per_sep=1]])
 -- Function: binascii.hexlify (data[, sep[, bytes_per_sep=1]])

     Return the hexadecimal representation of the binary 'data'.  Every
     byte of 'data' is converted into the corresponding 2-digit hex
     representation.  The returned bytes object is therefore twice as
     long as the length of 'data'.

     Similar functionality (but returning a text string) is also
     conveniently accessible using the *note bytes.hex(): d93. method.

     If 'sep' is specified, it must be a single character str or bytes
     object.  It will be inserted in the output after every
     'bytes_per_sep' input bytes.  Separator placement is counted from
     the right end of the output by default, if you wish to count from
     the left, supply a negative 'bytes_per_sep' value.

          >>> import binascii
          >>> binascii.b2a_hex(b'\xb9\x01\xef')
          b'b901ef'
          >>> binascii.hexlify(b'\xb9\x01\xef', '-')
          b'b9-01-ef'
          >>> binascii.b2a_hex(b'\xb9\x01\xef', b'_', 2)
          b'b9_01ef'
          >>> binascii.b2a_hex(b'\xb9\x01\xef', b' ', -2)
          b'b901 ef'

     Changed in version 3.8: The 'sep' and 'bytes_per_sep' parameters
     were added.

 -- Function: binascii.a2b_hex (hexstr)
 -- Function: binascii.unhexlify (hexstr)

     Return the binary data represented by the hexadecimal string
     'hexstr'.  This function is the inverse of *note b2a_hex(): 25cd.
     'hexstr' must contain an even number of hexadecimal digits (which
     can be upper or lower case), otherwise an *note Error: 1061.
     exception is raised.

     Similar functionality (accepting only text string arguments, but
     more liberal towards whitespace) is also accessible using the *note
     bytes.fromhex(): b08. class method.

 -- Exception: binascii.Error

     Exception raised on errors.  These are usually programming errors.

 -- Exception: binascii.Incomplete

     Exception raised on incomplete data.  These are usually not
     programming errors, but may be handled by reading a little more
     data and trying again.

See also
........

Module *note base64: e.

     Support for RFC compliant base64-style encoding in base 16, 32, 64,
     and 85.

Module *note quopri: b7.

     Support for quoted-printable encoding used in MIME email messages.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3548.html

   (2) https://datatracker.ietf.org/doc/html/rfc3548.html

   (3) https://datatracker.ietf.org/doc/html/rfc1522.html


File: python.info,  Node: quopri — Encode and decode MIME quoted-printable data,  Prev: binascii — Convert between binary and ASCII,  Up: Internet Data Handling

5.20.7 ‘quopri’ — Encode and decode MIME quoted-printable data
--------------------------------------------------------------

'Source code:' Lib/quopri.py(1)

__________________________________________________________________

This module performs quoted-printable transport encoding and decoding,
as defined in RFC 1521(2): “MIME (Multipurpose Internet Mail Extensions)
Part One: Mechanisms for Specifying and Describing the Format of
Internet Message Bodies”.  The quoted-printable encoding is designed for
data where there are relatively few nonprintable characters; the base64
encoding scheme available via the *note base64: e. module is more
compact if there are many such characters, as when sending a graphics
file.

 -- Function: quopri.decode (input, output, header=False)

     Decode the contents of the 'input' file and write the resulting
     decoded binary data to the 'output' file.  'input' and 'output'
     must be *note binary file objects: 1208.  If the optional argument
     'header' is present and true, underscore will be decoded as space.
     This is used to decode “Q”-encoded headers as described in RFC
     1522(3): “MIME (Multipurpose Internet Mail Extensions) Part Two:
     Message Header Extensions for Non-ASCII Text”.

 -- Function: quopri.encode (input, output, quotetabs, header=False)

     Encode the contents of the 'input' file and write the resulting
     quoted-printable data to the 'output' file.  'input' and 'output'
     must be *note binary file objects: 1208.  'quotetabs', a
     non-optional flag which controls whether to encode embedded spaces
     and tabs; when true it encodes such embedded whitespace, and when
     false it leaves them unencoded.  Note that spaces and tabs
     appearing at the end of lines are always encoded, as per RFC
     1521(4).  'header' is a flag which controls if spaces are encoded
     as underscores as per RFC 1522(5).

 -- Function: quopri.decodestring (s, header=False)

     Like *note decode(): 25d0, except that it accepts a source *note
     bytes: 1c2. and returns the corresponding decoded ‘bytes’.

 -- Function: quopri.encodestring (s, quotetabs=False, header=False)

     Like *note encode(): 25cf, except that it accepts a source *note
     bytes: 1c2. and returns the corresponding encoded ‘bytes’.  By
     default, it sends a ‘False’ value to 'quotetabs' parameter of the
     ‘encode()’ function.

See also
........

Module *note base64: e.

     Encode and decode MIME base64 data

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/quopri.py

   (2) https://datatracker.ietf.org/doc/html/rfc1521.html

   (3) https://datatracker.ietf.org/doc/html/rfc1522.html

   (4) https://datatracker.ietf.org/doc/html/rfc1521.html

   (5) https://datatracker.ietf.org/doc/html/rfc1522.html


File: python.info,  Node: Structured Markup Processing Tools,  Next: Internet Protocols and Support,  Prev: Internet Data Handling,  Up: The Python Standard Library

5.21 Structured Markup Processing Tools
=======================================

Python supports a variety of modules to work with various forms of
structured data markup.  This includes modules to work with the Standard
Generalized Markup Language (SGML) and the Hypertext Markup Language
(HTML), and several interfaces for working with the Extensible Markup
Language (XML).

* Menu:

* html — HyperText Markup Language support::
* html.parser — Simple HTML and XHTML parser: html parser — Simple HTML and XHTML parser.
* html.entities — Definitions of HTML general entities: html entities — Definitions of HTML general entities.
* XML Processing Modules::
* xml.etree.ElementTree — The ElementTree XML API: xml etree ElementTree — The ElementTree XML API.
* xml.dom — The Document Object Model API: xml dom — The Document Object Model API.
* xml.dom.minidom — Minimal DOM implementation: xml dom minidom — Minimal DOM implementation.
* xml.dom.pulldom — Support for building partial DOM trees: xml dom pulldom — Support for building partial DOM trees.
* xml.sax — Support for SAX2 parsers: xml sax — Support for SAX2 parsers.
* xml.sax.handler — Base classes for SAX handlers: xml sax handler — Base classes for SAX handlers.
* xml.sax.saxutils — SAX Utilities: xml sax saxutils — SAX Utilities.
* xml.sax.xmlreader — Interface for XML parsers: xml sax xmlreader — Interface for XML parsers.
* xml.parsers.expat — Fast XML parsing using Expat: xml parsers expat — Fast XML parsing using Expat.


File: python.info,  Node: html — HyperText Markup Language support,  Next: html parser — Simple HTML and XHTML parser,  Up: Structured Markup Processing Tools

5.21.1 ‘html’ — HyperText Markup Language support
-------------------------------------------------

'Source code:' Lib/html/__init__.py(1)

__________________________________________________________________

This module defines utilities to manipulate HTML.

 -- Function: html.escape (s, quote=True)

     Convert the characters ‘&’, ‘<’ and ‘>’ in string 's' to HTML-safe
     sequences.  Use this if you need to display text that might contain
     such characters in HTML. If the optional flag 'quote' is true (the
     default), the characters (‘"’) and (‘'’) are also translated; this
     helps for inclusion in an HTML attribute value delimited by quotes,
     as in ‘<a href="...">’.  If 'quote' is set to false, the characters
     (‘"’) and (‘'’) are not translated.

     Added in version 3.2.

 -- Function: html.unescape (s)

     Convert all named and numeric character references (e.g.  ‘&gt;’,
     ‘&#62;’, ‘&#x3e;’) in the string 's' to the corresponding Unicode
     characters.  This function uses the rules defined by the HTML 5
     standard for both valid and invalid character references, and the
     *note list of HTML 5 named character references: 1116.

     Added in version 3.4.

__________________________________________________________________

Submodules in the ‘html’ package are:

   * *note html.parser: 6d. – HTML/XHTML parser with lenient parsing
     mode

   * *note html.entities: 6c. – HTML entity definitions

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/html/__init__.py


File: python.info,  Node: html parser — Simple HTML and XHTML parser,  Next: html entities — Definitions of HTML general entities,  Prev: html — HyperText Markup Language support,  Up: Structured Markup Processing Tools

5.21.2 ‘html.parser’ — Simple HTML and XHTML parser
---------------------------------------------------

'Source code:' Lib/html/parser.py(1)

__________________________________________________________________

This module defines a class *note HTMLParser: 87e. which serves as the
basis for parsing text files formatted in HTML (HyperText Mark-up
Language) and XHTML.

 -- Class: html.parser.HTMLParser (*, convert_charrefs=True,
          scripting=False)

     Create a parser instance able to parse invalid markup.

     If 'convert_charrefs' is true (the default), all character
     references (except the ones in elements like ‘script’ and ‘style’)
     are automatically converted to the corresponding Unicode
     characters.

     If 'scripting' is false (the default), the content of the
     ‘noscript’ element is parsed normally; if it’s true, it’s returned
     as is without being parsed.

     An ‘HTMLParser’ instance is fed HTML data and calls handler methods
     when start tags, end tags, text, comments, and other markup
     elements are encountered.  The user should subclass ‘HTMLParser’
     and override its methods to implement the desired behavior.

     This parser does not check that end tags match start tags or call
     the end-tag handler for elements which are closed implicitly by
     closing an outer element.

     Changed in version 3.4: 'convert_charrefs' keyword argument added.

     Changed in version 3.5: The default value for argument
     'convert_charrefs' is now ‘True’.

     Changed in version 3.13.10: Added the 'scripting' parameter.

* Menu:

* Example HTML Parser Application::
* HTMLParser Methods::
* Examples: Examples<24>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/html/parser.py


File: python.info,  Node: Example HTML Parser Application,  Next: HTMLParser Methods,  Up: html parser — Simple HTML and XHTML parser

5.21.2.1 Example HTML Parser Application
........................................

As a basic example, below is a simple HTML parser that uses the *note
HTMLParser: 87e. class to print out start tags, end tags, and data as
they are encountered:

     from html.parser import HTMLParser

     class MyHTMLParser(HTMLParser):
         def handle_starttag(self, tag, attrs):
             print("Encountered a start tag:", tag)

         def handle_endtag(self, tag):
             print("Encountered an end tag :", tag)

         def handle_data(self, data):
             print("Encountered some data  :", data)

     parser = MyHTMLParser()
     parser.feed('<html><head><title>Test</title></head>'
                 '<body><h1>Parse me!</h1></body></html>')

The output will then be:

     Encountered a start tag: html
     Encountered a start tag: head
     Encountered a start tag: title
     Encountered some data  : Test
     Encountered an end tag : title
     Encountered an end tag : head
     Encountered a start tag: body
     Encountered a start tag: h1
     Encountered some data  : Parse me!
     Encountered an end tag : h1
     Encountered an end tag : body
     Encountered an end tag : html


File: python.info,  Node: HTMLParser Methods,  Next: Examples<24>,  Prev: Example HTML Parser Application,  Up: html parser — Simple HTML and XHTML parser

5.21.2.2 ‘HTMLParser’ Methods
.............................

*note HTMLParser: 87e. instances have the following methods:

 -- Method: HTMLParser.feed (data)

     Feed some text to the parser.  It is processed insofar as it
     consists of complete elements; incomplete data is buffered until
     more data is fed or *note close(): 164d. is called.  'data' must be
     *note str: 44f.

 -- Method: HTMLParser.close ()

     Force processing of all buffered data as if it were followed by an
     end-of-file mark.  This method may be redefined by a derived class
     to define additional processing at the end of the input, but the
     redefined version should always call the *note HTMLParser: 87e.
     base class method ‘close()’.

 -- Method: HTMLParser.reset ()

     Reset the instance.  Loses all unprocessed data.  This is called
     implicitly at instantiation time.

 -- Method: HTMLParser.getpos ()

     Return current line number and offset.

 -- Method: HTMLParser.get_starttag_text ()

     Return the text of the most recently opened start tag.  This should
     not normally be needed for structured processing, but may be useful
     in dealing with HTML “as deployed” or for re-generating input with
     minimal changes (whitespace between attributes can be preserved,
     etc.).

The following methods are called when data or markup elements are
encountered and they are meant to be overridden in a subclass.  The base
class implementations do nothing (except for *note handle_startendtag():
39a1.):

 -- Method: HTMLParser.handle_starttag (tag, attrs)

     This method is called to handle the start tag of an element (e.g.
     ‘<div id="main">’).

     The 'tag' argument is the name of the tag converted to lower case.
     The 'attrs' argument is a list of ‘(name, value)’ pairs containing
     the attributes found inside the tag’s ‘<>’ brackets.  The 'name'
     will be translated to lower case, and quotes in the 'value' have
     been removed, and character and entity references have been
     replaced.

     For instance, for the tag ‘<A HREF="https://www.cwi.nl/">’, this
     method would be called as ‘handle_starttag('a', [('href',
     'https://www.cwi.nl/')])’.

     All entity references from *note html.entities: 6c. are replaced in
     the attribute values.

 -- Method: HTMLParser.handle_endtag (tag)

     This method is called to handle the end tag of an element (e.g.
     ‘</div>’).

     The 'tag' argument is the name of the tag converted to lower case.

 -- Method: HTMLParser.handle_startendtag (tag, attrs)

     Similar to *note handle_starttag(): 39a2, but called when the
     parser encounters an XHTML-style empty tag (‘<img ... />’).  This
     method may be overridden by subclasses which require this
     particular lexical information; the default implementation simply
     calls ‘handle_starttag()’ and *note handle_endtag(): 39a3.

 -- Method: HTMLParser.handle_data (data)

     This method is called to process arbitrary data (e.g.  text nodes
     and the content of elements like ‘script’ and ‘style’).

 -- Method: HTMLParser.handle_entityref (name)

     This method is called to process a named character reference of the
     form ‘&name;’ (e.g.  ‘&gt;’), where 'name' is a general entity
     reference (e.g.  ‘'gt'’).  This method is only called if
     'convert_charrefs' is false.

 -- Method: HTMLParser.handle_charref (name)

     This method is called to process decimal and hexadecimal numeric
     character references of the form ‘&#NNN;’ and ‘&#xNNN;’.  For
     example, the decimal equivalent for ‘&gt;’ is ‘&#62;’, whereas the
     hexadecimal is ‘&#x3E;’; in this case the method will receive
     ‘'62'’ or ‘'x3E'’.  This method is only called if
     'convert_charrefs' is false.

 -- Method: HTMLParser.handle_comment (data)

     This method is called when a comment is encountered (e.g.
     ‘<!--comment-->’).

     For example, the comment ‘<!-- comment -->’ will cause this method
     to be called with the argument ‘' comment '’.

     The content of Internet Explorer conditional comments (condcoms)
     will also be sent to this method, so, for ‘<!--[if IE
     9]>IE9-specific content<![endif]-->’, this method will receive
     ‘'[if IE 9]>IE9-specific content<![endif]'’.

 -- Method: HTMLParser.handle_decl (decl)

     This method is called to handle an HTML doctype declaration (e.g.
     ‘<!DOCTYPE html>’).

     The 'decl' parameter will be the entire contents of the declaration
     inside the ‘<!...>’ markup (e.g.  ‘'DOCTYPE html'’).

 -- Method: HTMLParser.handle_pi (data)

     Method called when a processing instruction is encountered.  The
     'data' parameter will contain the entire processing instruction.
     For example, for the processing instruction ‘<?proc color='red'>’,
     this method would be called as ‘handle_pi("proc color='red'")’.  It
     is intended to be overridden by a derived class; the base class
     implementation does nothing.

          Note: The *note HTMLParser: 87e. class uses the SGML syntactic
          rules for processing instructions.  An XHTML processing
          instruction using the trailing ‘'?'’ will cause the ‘'?'’ to
          be included in 'data'.

 -- Method: HTMLParser.unknown_decl (data)

     This method is called when an unrecognized declaration is read by
     the parser.

     The 'data' parameter will be the entire contents of the declaration
     inside the ‘<![...]>’ markup.  It is sometimes useful to be
     overridden by a derived class.  The base class implementation does
     nothing.


File: python.info,  Node: Examples<24>,  Prev: HTMLParser Methods,  Up: html parser — Simple HTML and XHTML parser

5.21.2.3 Examples
.................

The following class implements a parser that will be used to illustrate
more examples:

     from html.parser import HTMLParser
     from html.entities import name2codepoint

     class MyHTMLParser(HTMLParser):
         def handle_starttag(self, tag, attrs):
             print("Start tag:", tag)
             for attr in attrs:
                 print("     attr:", attr)

         def handle_endtag(self, tag):
             print("End tag  :", tag)

         def handle_data(self, data):
             print("Data     :", data)

         def handle_comment(self, data):
             print("Comment  :", data)

         def handle_entityref(self, name):
             c = chr(name2codepoint[name])
             print("Named ent:", c)

         def handle_charref(self, name):
             if name.startswith('x'):
                 c = chr(int(name[1:], 16))
             else:
                 c = chr(int(name))
             print("Num ent  :", c)

         def handle_decl(self, data):
             print("Decl     :", data)

     parser = MyHTMLParser()

Parsing a doctype:

     >>> parser.feed('<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" '
     ...             '"http://www.w3.org/TR/html4/strict.dtd">')
     Decl     : DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"

Parsing an element with a few attributes and a title:

     >>> parser.feed('<img src="python-logo.png" alt="The Python logo">')
     Start tag: img
          attr: ('src', 'python-logo.png')
          attr: ('alt', 'The Python logo')
     >>>
     >>> parser.feed('<h1>Python</h1>')
     Start tag: h1
     Data     : Python
     End tag  : h1

The content of elements like ‘script’ and ‘style’ is returned as is,
without further parsing:

     >>> parser.feed('<style type="text/css">#python { color: green }</style>')
     Start tag: style
          attr: ('type', 'text/css')
     Data     : #python { color: green }
     End tag  : style

     >>> parser.feed('<script type="text/javascript">'
     ...             'alert("<strong>hello! &#9786;</strong>");</script>')
     Start tag: script
          attr: ('type', 'text/javascript')
     Data     : alert("<strong>hello! &#9786;</strong>");
     End tag  : script

Parsing comments:

     >>> parser.feed('<!--a comment-->'
     ...             '<!--[if IE 9]>IE-specific content<![endif]-->')
     Comment  : a comment
     Comment  : [if IE 9]>IE-specific content<![endif]

Parsing named and numeric character references and converting them to
the correct char (note: these 3 references are all equivalent to ‘'>'’):

     >>> parser = MyHTMLParser()
     >>> parser.feed('&gt;&#62;&#x3E;')
     Data     : >>>

     >>> parser = MyHTMLParser(convert_charrefs=False)
     >>> parser.feed('&gt;&#62;&#x3E;')
     Named ent: >
     Num ent  : >
     Num ent  : >

Feeding incomplete chunks to *note feed(): 399d. works, but *note
handle_data(): 39a4. might be called more than once if
'convert_charrefs' is false:

     >>> for chunk in ['<sp', 'an>buff', 'ered', ' text</s', 'pan>']:
     ...     parser.feed(chunk)
     ...
     Start tag: span
     Data     : buff
     Data     : ered
     Data     :  text
     End tag  : span

Parsing invalid HTML (e.g.  unquoted attributes) also works:

     >>> parser.feed('<p><a class=link href=#main>tag soup</p ></a>')
     Start tag: p
     Start tag: a
          attr: ('class', 'link')
          attr: ('href', '#main')
     Data     : tag soup
     End tag  : p
     End tag  : a


File: python.info,  Node: html entities — Definitions of HTML general entities,  Next: XML Processing Modules,  Prev: html parser — Simple HTML and XHTML parser,  Up: Structured Markup Processing Tools

5.21.3 ‘html.entities’ — Definitions of HTML general entities
-------------------------------------------------------------

'Source code:' Lib/html/entities.py(1)

__________________________________________________________________

This module defines four dictionaries, *note html5: 1116, *note
name2codepoint: 39b0, *note codepoint2name: 39b1, and *note entitydefs:
39b2.

 -- Data: html.entities.html5

     A dictionary that maps HTML5 named character references (2) to the
     equivalent Unicode character(s), e.g.  ‘html5['gt;'] == '>'’.  Note
     that the trailing semicolon is included in the name (e.g.
     ‘'gt;'’), however some of the names are accepted by the standard
     even without the semicolon: in this case the name is present with
     and without the ‘';'’.  See also *note html.unescape(): 961.

     Added in version 3.3.

 -- Data: html.entities.entitydefs

     A dictionary mapping XHTML 1.0 entity definitions to their
     replacement text in ISO Latin-1.

 -- Data: html.entities.name2codepoint

     A dictionary that maps HTML4 entity names to the Unicode code
     points.

 -- Data: html.entities.codepoint2name

     A dictionary that maps Unicode code points to HTML4 entity names.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/html/entities.py

   (2) See
‘https://html.spec.whatwg.org/multipage/named-characters.html#named-character-references’


File: python.info,  Node: XML Processing Modules,  Next: xml etree ElementTree — The ElementTree XML API,  Prev: html entities — Definitions of HTML general entities,  Up: Structured Markup Processing Tools

5.21.4 XML Processing Modules
-----------------------------

'Source code:' Lib/xml/(1)

__________________________________________________________________

Python’s interfaces for processing XML are grouped in the ‘xml’ package.

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

It is important to note that modules in the ‘xml’ package require that
there be at least one SAX-compliant XML parser available.  The Expat
parser is included with Python, so the *note xml.parsers.expat: 126.
module will always be available.

The documentation for the *note xml.dom: 121. and *note xml.sax: 129.
packages are the definition of the Python bindings for the DOM and SAX
interfaces.

The XML handling submodules are:

   * *note xml.etree.ElementTree: 125.: the ElementTree API, a simple
     and lightweight XML processor

   * *note xml.dom: 121.: the DOM API definition

   * *note xml.dom.minidom: 122.: a minimal DOM implementation

   * *note xml.dom.pulldom: 123.: support for building partial DOM trees

   * *note xml.sax: 129.: SAX2 base classes and convenience functions

   * *note xml.parsers.expat: 126.: the Expat parser binding
* Menu:

* XML security::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/xml/


File: python.info,  Node: XML security,  Up: XML Processing Modules

5.21.4.1 XML security
.....................

An attacker can abuse XML features to carry out denial of service
attacks, access local files, generate network connections to other
machines, or circumvent firewalls when attacker-controlled XML is being
parsed, in Python or elsewhere.

The built-in XML parsers of Python rely on the library libexpat(1),
commonly called Expat, for parsing XML.

By default, Expat itself does not access local files or create network
connections.

Expat versions lower than 2.7.2 may be vulnerable to the “billion
laughs”, “quadratic blowup” and “large tokens” vulnerabilities, or to
disproportional use of dynamic memory.  Python bundles a copy of Expat,
and whether Python uses the bundled or a system-wide Expat, depends on
how the Python interpreter *note has been configured: 18d0. in your
environment.  Python may be vulnerable if it uses such older versions of
Expat.  Check ‘pyexpat.EXPAT_VERSION’.

*note xmlrpc: 12d. is 'vulnerable' to the “decompression bomb” attack.

billion laughs / exponential entity expansion

     The Billion Laughs(2) attack – also known as exponential entity
     expansion – uses multiple levels of nested entities.  Each entity
     refers to another entity several times, and the final entity
     definition contains a small string.  The exponential expansion
     results in several gigabytes of text and consumes lots of memory
     and CPU time.

quadratic blowup entity expansion

     A quadratic blowup attack is similar to a Billion Laughs(3) attack;
     it abuses entity expansion, too.  Instead of nested entities it
     repeats one large entity with a couple of thousand chars over and
     over again.  The attack isn’t as efficient as the exponential case
     but it avoids triggering parser countermeasures that forbid deeply
     nested entities.

decompression bomb

     Decompression bombs (aka ZIP bomb(4)) apply to all XML libraries
     that can parse compressed XML streams such as gzipped HTTP streams
     or LZMA-compressed files.  For an attacker it can reduce the amount
     of transmitted data by three magnitudes or more.

large tokens

     Expat needs to re-parse unfinished tokens; without the protection
     introduced in Expat 2.6.0, this can lead to quadratic runtime that
     can be used to cause denial of service in the application parsing
     XML. The issue is known as CVE 2023-52425(5).

   ---------- Footnotes ----------

   (1) https://github.com/libexpat/libexpat

   (2) https://en.wikipedia.org/wiki/Billion_laughs

   (3) https://en.wikipedia.org/wiki/Billion_laughs

   (4) https://en.wikipedia.org/wiki/Zip_bomb

   (5) https://www.cve.org/CVERecord?id=CVE-2023-52425


File: python.info,  Node: xml etree ElementTree — The ElementTree XML API,  Next: xml dom — The Document Object Model API,  Prev: XML Processing Modules,  Up: Structured Markup Processing Tools

5.21.5 ‘xml.etree.ElementTree’ — The ElementTree XML API
--------------------------------------------------------

'Source code:' Lib/xml/etree/ElementTree.py(1)

__________________________________________________________________

The ‘xml.etree.ElementTree’ module implements a simple and efficient API
for parsing and creating XML data.

Changed in version 3.3: This module will use a fast implementation
whenever available.

Deprecated since version 3.3: The ‘xml.etree.cElementTree’ module is
deprecated.

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

* Menu:

* Tutorial: Tutorial<3>.
* XPath support::
* Reference: Reference<4>.
* XInclude support::
* Reference: Reference<5>.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/etree/ElementTree.py


File: python.info,  Node: Tutorial<3>,  Next: XPath support,  Up: xml etree ElementTree — The ElementTree XML API

5.21.5.1 Tutorial
.................

This is a short tutorial for using ‘xml.etree.ElementTree’ (‘ET’ in
short).  The goal is to demonstrate some of the building blocks and
basic concepts of the module.

* Menu:

* XML tree and elements::
* Parsing XML::
* Pull API for non-blocking parsing::
* Finding interesting elements::
* Modifying an XML File::
* Building XML documents::
* Parsing XML with Namespaces::


File: python.info,  Node: XML tree and elements,  Next: Parsing XML,  Up: Tutorial<3>

5.21.5.2 XML tree and elements
..............................

XML is an inherently hierarchical data format, and the most natural way
to represent it is with a tree.  ‘ET’ has two classes for this purpose -
*note ElementTree: 958. represents the whole XML document as a tree, and
*note Element: 310. represents a single node in this tree.  Interactions
with the whole document (reading and writing to/from files) are usually
done on the ‘ElementTree’ level.  Interactions with a single XML element
and its sub-elements are done on the ‘Element’ level.


File: python.info,  Node: Parsing XML,  Next: Pull API for non-blocking parsing,  Prev: XML tree and elements,  Up: Tutorial<3>

5.21.5.3 Parsing XML
....................

We’ll be using the fictive ‘country_data.xml’ XML document as the sample
data for this section:

     <?xml version="1.0"?>
     <data>
         <country name="Liechtenstein">
             <rank>1</rank>
             <year>2008</year>
             <gdppc>141100</gdppc>
             <neighbor name="Austria" direction="E"/>
             <neighbor name="Switzerland" direction="W"/>
         </country>
         <country name="Singapore">
             <rank>4</rank>
             <year>2011</year>
             <gdppc>59900</gdppc>
             <neighbor name="Malaysia" direction="N"/>
         </country>
         <country name="Panama">
             <rank>68</rank>
             <year>2011</year>
             <gdppc>13600</gdppc>
             <neighbor name="Costa Rica" direction="W"/>
             <neighbor name="Colombia" direction="E"/>
         </country>
     </data>

We can import this data by reading from a file:

     import xml.etree.ElementTree as ET
     tree = ET.parse('country_data.xml')
     root = tree.getroot()

Or directly from a string:

     root = ET.fromstring(country_data_as_string)

*note fromstring(): 39c1. parses XML from a string directly into an
*note Element: 310, which is the root element of the parsed tree.  Other
parsing functions may create an *note ElementTree: 958.  Check the
documentation to be sure.

As an *note Element: 310, ‘root’ has a tag and a dictionary of
attributes:

     >>> root.tag
     'data'
     >>> root.attrib
     {}

It also has children nodes over which we can iterate:

     >>> for child in root:
     ...     print(child.tag, child.attrib)
     ...
     country {'name': 'Liechtenstein'}
     country {'name': 'Singapore'}
     country {'name': 'Panama'}

Children are nested, and we can access specific child nodes by index:

     >>> root[0][1].text
     '2008'

     Note: Not all elements of the XML input will end up as elements of
     the parsed tree.  Currently, this module skips over any XML
     comments, processing instructions, and document type declarations
     in the input.  Nevertheless, trees built using this module’s API
     rather than parsing from XML text can have comments and processing
     instructions in them; they will be included when generating XML
     output.  A document type declaration may be accessed by passing a
     custom *note TreeBuilder: a63. instance to the *note XMLParser:
     a62. constructor.


File: python.info,  Node: Pull API for non-blocking parsing,  Next: Finding interesting elements,  Prev: Parsing XML,  Up: Tutorial<3>

5.21.5.4 Pull API for non-blocking parsing
..........................................

Most parsing functions provided by this module require the whole
document to be read at once before returning any result.  It is possible
to use an *note XMLParser: a62. and feed data into it incrementally, but
it is a push API that calls methods on a callback target, which is too
low-level and inconvenient for most needs.  Sometimes what the user
really wants is to be able to parse XML incrementally, without blocking
operations, while enjoying the convenience of fully constructed *note
Element: 310. objects.

The most powerful tool for doing this is *note XMLPullParser: 102e.  It
does not require a blocking read to obtain the XML data, and is instead
fed with data incrementally with *note XMLPullParser.feed(): 39c3.
calls.  To get the parsed XML elements, call *note
XMLPullParser.read_events(): 39c4.  Here is an example:

     >>> parser = ET.XMLPullParser(['start', 'end'])
     >>> parser.feed('<mytag>sometext')
     >>> list(parser.read_events())
     [('start', <Element 'mytag' at 0x7fa66db2be58>)]
     >>> parser.feed(' more text</mytag>')
     >>> for event, elem in parser.read_events():
     ...     print(event)
     ...     print(elem.tag, 'text=', elem.text)
     ...
     end
     mytag text= sometext more text

The obvious use case is applications that operate in a non-blocking
fashion where the XML data is being received from a socket or read
incrementally from some storage device.  In such cases, blocking reads
are unacceptable.

Because it’s so flexible, *note XMLPullParser: 102e. can be inconvenient
to use for simpler use-cases.  If you don’t mind your application
blocking on reading XML data but would still like to have incremental
parsing capabilities, take a look at *note iterparse(): 273.  It can be
useful when you’re reading a large XML document and don’t want to hold
it wholly in memory.

Where 'immediate' feedback through events is wanted, calling method
*note XMLPullParser.flush(): 270. can help reduce delay; please make
sure to study the related security notes.


File: python.info,  Node: Finding interesting elements,  Next: Modifying an XML File,  Prev: Pull API for non-blocking parsing,  Up: Tutorial<3>

5.21.5.5 Finding interesting elements
.....................................

*note Element: 310. has some useful methods that help iterate
recursively over all the sub-tree below it (its children, their
children, and so on).  For example, *note Element.iter(): 139a.:

     >>> for neighbor in root.iter('neighbor'):
     ...     print(neighbor.attrib)
     ...
     {'name': 'Austria', 'direction': 'E'}
     {'name': 'Switzerland', 'direction': 'W'}
     {'name': 'Malaysia', 'direction': 'N'}
     {'name': 'Costa Rica', 'direction': 'W'}
     {'name': 'Colombia', 'direction': 'E'}

*note Element.findall(): 166c. finds only elements with a tag which are
direct children of the current element.  *note Element.find(): 166a.
finds the 'first' child with a particular tag, and *note Element.text:
39c6. accesses the element’s text content.  *note Element.get(): 39c7.
accesses the element’s attributes:

     >>> for country in root.findall('country'):
     ...     rank = country.find('rank').text
     ...     name = country.get('name')
     ...     print(name, rank)
     ...
     Liechtenstein 1
     Singapore 4
     Panama 68

More sophisticated specification of which elements to look for is
possible by using *note XPath: bcb.


File: python.info,  Node: Modifying an XML File,  Next: Building XML documents,  Prev: Finding interesting elements,  Up: Tutorial<3>

5.21.5.6 Modifying an XML File
..............................

*note ElementTree: 958. provides a simple way to build XML documents and
write them to files.  The *note ElementTree.write(): aaa. method serves
this purpose.

Once created, an *note Element: 310. object may be manipulated by
directly changing its fields (such as *note Element.text: 39c6.), adding
and modifying attributes (*note Element.set(): 39c9. method), as well as
adding new children (for example with *note Element.append(): 39ca.).

Let’s say we want to add one to each country’s rank, and add an
‘updated’ attribute to the rank element:

     >>> for rank in root.iter('rank'):
     ...     new_rank = int(rank.text) + 1
     ...     rank.text = str(new_rank)
     ...     rank.set('updated', 'yes')
     ...
     >>> tree.write('output.xml')

Our XML now looks like this:

     <?xml version="1.0"?>
     <data>
         <country name="Liechtenstein">
             <rank updated="yes">2</rank>
             <year>2008</year>
             <gdppc>141100</gdppc>
             <neighbor name="Austria" direction="E"/>
             <neighbor name="Switzerland" direction="W"/>
         </country>
         <country name="Singapore">
             <rank updated="yes">5</rank>
             <year>2011</year>
             <gdppc>59900</gdppc>
             <neighbor name="Malaysia" direction="N"/>
         </country>
         <country name="Panama">
             <rank updated="yes">69</rank>
             <year>2011</year>
             <gdppc>13600</gdppc>
             <neighbor name="Costa Rica" direction="W"/>
             <neighbor name="Colombia" direction="E"/>
         </country>
     </data>

We can remove elements using *note Element.remove(): 166e.  Let’s say we
want to remove all countries with a rank higher than 50:

     >>> for country in root.findall('country'):
     ...     # using root.findall() to avoid removal during traversal
     ...     rank = int(country.find('rank').text)
     ...     if rank > 50:
     ...         root.remove(country)
     ...
     >>> tree.write('output.xml')

Note that concurrent modification while iterating can lead to problems,
just like when iterating and modifying Python lists or dicts.
Therefore, the example first collects all matching elements with
‘root.findall()’, and only then iterates over the list of matches.

Our XML now looks like this:

     <?xml version="1.0"?>
     <data>
         <country name="Liechtenstein">
             <rank updated="yes">2</rank>
             <year>2008</year>
             <gdppc>141100</gdppc>
             <neighbor name="Austria" direction="E"/>
             <neighbor name="Switzerland" direction="W"/>
         </country>
         <country name="Singapore">
             <rank updated="yes">5</rank>
             <year>2011</year>
             <gdppc>59900</gdppc>
             <neighbor name="Malaysia" direction="N"/>
         </country>
     </data>


File: python.info,  Node: Building XML documents,  Next: Parsing XML with Namespaces,  Prev: Modifying an XML File,  Up: Tutorial<3>

5.21.5.7 Building XML documents
...............................

The *note SubElement(): 39cc. function also provides a convenient way to
create new sub-elements for a given element:

     >>> a = ET.Element('a')
     >>> b = ET.SubElement(a, 'b')
     >>> c = ET.SubElement(a, 'c')
     >>> d = ET.SubElement(c, 'd')
     >>> ET.dump(a)
     <a><b /><c><d /></c></a>


File: python.info,  Node: Parsing XML with Namespaces,  Prev: Building XML documents,  Up: Tutorial<3>

5.21.5.8 Parsing XML with Namespaces
....................................

If the XML input has namespaces(1), tags and attributes with prefixes in
the form ‘prefix:sometag’ get expanded to ‘{uri}sometag’ where the
'prefix' is replaced by the full 'URI'. Also, if there is a default
namespace(2), that full URI gets prepended to all of the non-prefixed
tags.

Here is an XML example that incorporates two namespaces, one with the
prefix “fictional” and the other serving as the default namespace:

     <?xml version="1.0"?>
     <actors xmlns:fictional="http://characters.example.com"
             xmlns="http://people.example.com">
         <actor>
             <name>John Cleese</name>
             <fictional:character>Lancelot</fictional:character>
             <fictional:character>Archie Leach</fictional:character>
         </actor>
         <actor>
             <name>Eric Idle</name>
             <fictional:character>Sir Robin</fictional:character>
             <fictional:character>Gunther</fictional:character>
             <fictional:character>Commander Clement</fictional:character>
         </actor>
     </actors>

One way to search and explore this XML example is to manually add the
URI to every tag or attribute in the xpath of a *note find(): 166a. or
*note findall(): 166c.:

     root = fromstring(xml_text)
     for actor in root.findall('{http://people.example.com}actor'):
         name = actor.find('{http://people.example.com}name')
         print(name.text)
         for char in actor.findall('{http://characters.example.com}character'):
             print(' |-->', char.text)

A better way to search the namespaced XML example is to create a
dictionary with your own prefixes and use those in the search functions:

     ns = {'real_person': 'http://people.example.com',
           'role': 'http://characters.example.com'}

     for actor in root.findall('real_person:actor', ns):
         name = actor.find('real_person:name', ns)
         print(name.text)
         for char in actor.findall('role:character', ns):
             print(' |-->', char.text)

These two approaches both output:

     John Cleese
      |--> Lancelot
      |--> Archie Leach
     Eric Idle
      |--> Sir Robin
      |--> Gunther
      |--> Commander Clement

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/XML_namespace

   (2) https://www.w3.org/TR/xml-names/#defaulting


File: python.info,  Node: XPath support,  Next: Reference<4>,  Prev: Tutorial<3>,  Up: xml etree ElementTree — The ElementTree XML API

5.21.5.9 XPath support
......................

This module provides limited support for XPath expressions(1) for
locating elements in a tree.  The goal is to support a small subset of
the abbreviated syntax; a full XPath engine is outside the scope of the
module.

* Menu:

* Example: Example<8>.
* Supported XPath syntax::

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/xpath


File: python.info,  Node: Example<8>,  Next: Supported XPath syntax,  Up: XPath support

5.21.5.10 Example
.................

Here’s an example that demonstrates some of the XPath capabilities of
the module.  We’ll be using the ‘countrydata’ XML document from the
*note Parsing XML: 39bf. section:

     import xml.etree.ElementTree as ET

     root = ET.fromstring(countrydata)

     # Top-level elements
     root.findall(".")

     # All 'neighbor' grand-children of 'country' children of the top-level
     # elements
     root.findall("./country/neighbor")

     # Nodes with name='Singapore' that have a 'year' child
     root.findall(".//year/..[@name='Singapore']")

     # 'year' nodes that are children of nodes with name='Singapore'
     root.findall(".//*[@name='Singapore']/year")

     # All 'neighbor' nodes that are the second child of their parent
     root.findall(".//neighbor[2]")

For XML with namespaces, use the usual qualified ‘{namespace}tag’
notation:

     # All dublin-core "title" tags in the document
     root.findall(".//{http://purl.org/dc/elements/1.1/}title")


File: python.info,  Node: Supported XPath syntax,  Prev: Example<8>,  Up: XPath support

5.21.5.11 Supported XPath syntax
................................

Syntax                      Meaning
                            
---------------------------------------------------------------------------------------
                            
‘tag’                       Selects all child elements with the given tag.  For
                            example, ‘spam’ selects all child elements named ‘spam’,
                            and ‘spam/egg’ selects all grandchildren named ‘egg’ in
                            all children named ‘spam’.  ‘{namespace}*’ selects all
                            tags in the given namespace, ‘{*}spam’ selects tags
                            named ‘spam’ in any (or no) namespace, and ‘{}*’ only
                            selects tags that are not in a namespace.
                            
                            Changed in version 3.8: Support for star-wildcards was
                            added.
                            
                            
‘*’                         Selects all child elements, including comments and
                            processing instructions.  For example, ‘*/egg’ selects
                            all grandchildren named ‘egg’.
                            
                            
‘.’                         Selects the current node.  This is mostly useful at the
                            beginning of the path, to indicate that it’s a relative
                            path.
                            
                            
‘//’                        Selects all subelements, on all levels beneath the
                            current element.  For example, ‘.//egg’ selects all
                            ‘egg’ elements in the entire tree.
                            
                            
‘..’                        Selects the parent element.  Returns ‘None’ if the path
                            attempts to reach the ancestors of the start element
                            (the element ‘find’ was called on).
                            
                            
‘[@attrib]’                 Selects all elements that have the given attribute.
                            
                            
‘[@attrib='value']’         Selects all elements for which the given attribute has
                            the given value.  The value cannot contain quotes.
                            
                            
‘[@attrib!='value']’        Selects all elements for which the given attribute does
                            not have the given value.  The value cannot contain
                            quotes.
                            
                            Added in version 3.10.
                            
                            
‘[tag]’                     Selects all elements that have a child named ‘tag’.
                            Only immediate children are supported.
                            
                            
‘[.='text']’                Selects all elements whose complete text content,
                            including descendants, equals the given ‘text’.
                            
                            Added in version 3.7.
                            
                            
‘[.!='text']’               Selects all elements whose complete text content,
                            including descendants, does not equal the given ‘text’.
                            
                            Added in version 3.10.
                            
                            
‘[tag='text']’              Selects all elements that have a child named ‘tag’ whose
                            complete text content, including descendants, equals the
                            given ‘text’.
                            
                            
‘[tag!='text']’             Selects all elements that have a child named ‘tag’ whose
                            complete text content, including descendants, does not
                            equal the given ‘text’.
                            
                            Added in version 3.10.
                            
                            
‘[position]’                Selects all elements that are located at the given
                            position.  The position can be either an integer (1 is
                            the first position), the expression ‘last()’ (for the
                            last position), or a position relative to the last
                            position (e.g.  ‘last()-1’).
                            

Predicates (expressions within square brackets) must be preceded by a
tag name, an asterisk, or another predicate.  ‘position’ predicates must
be preceded by a tag name.


File: python.info,  Node: Reference<4>,  Next: XInclude support,  Prev: XPath support,  Up: xml etree ElementTree — The ElementTree XML API

5.21.5.12 Reference
...................

* Menu:

* Functions: Functions<9>.


File: python.info,  Node: Functions<9>,  Up: Reference<4>

5.21.5.13 Functions
...................

 -- Function: xml.etree.ElementTree.canonicalize (xml_data=None, *,
          out=None, from_file=None, **options)

     C14N 2.0(1) transformation function.

     Canonicalization is a way to normalise XML output in a way that
     allows byte-by-byte comparisons and digital signatures.  It reduces
     the freedom that XML serializers have and instead generates a more
     constrained XML representation.  The main restrictions regard the
     placement of namespace declarations, the ordering of attributes,
     and ignorable whitespace.

     This function takes an XML data string ('xml_data') or a file path
     or file-like object ('from_file') as input, converts it to the
     canonical form, and writes it out using the 'out' file(-like)
     object, if provided, or returns it as a text string if not.  The
     output file receives text, not bytes.  It should therefore be
     opened in text mode with ‘utf-8’ encoding.

     Typical uses:

          xml_data = "<root>...</root>"
          print(canonicalize(xml_data))

          with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
              canonicalize(xml_data, out=out_file)

          with open("c14n_output.xml", mode='w', encoding='utf-8') as out_file:
              canonicalize(from_file="inputfile.xml", out=out_file)

     The configuration 'options' are as follows:

        - 'with_comments': set to true to include comments (default:
          false)

        - 
          'strip_text': set to true to strip whitespace before and after text content

               (default: false)

        - 
          'rewrite_prefixes': set to true to replace namespace prefixes by “n{number}”

               (default: false)

        - 
          'qname_aware_tags': a set of qname aware tag names in which prefixes

               should be replaced in text content (default: empty)

        - 
          'qname_aware_attrs': a set of qname aware attribute names in which prefixes

               should be replaced in text content (default: empty)

        - 'exclude_attrs': a set of attribute names that should not be
          serialised

        - 'exclude_tags': a set of tag names that should not be
          serialised

     In the option list above, “a set” refers to any collection or
     iterable of strings, no ordering is expected.

     Added in version 3.8.

 -- Function: xml.etree.ElementTree.Comment (text=None)

     Comment element factory.  This factory function creates a special
     element that will be serialized as an XML comment by the standard
     serializer.  The comment string can be either a bytestring or a
     Unicode string.  'text' is a string containing the comment string.
     Returns an element instance representing a comment.

     Note that *note XMLParser: a62. skips over comments in the input
     instead of creating comment objects for them.  An *note
     ElementTree: 958. will only contain comment nodes if they have been
     inserted into to the tree using one of the *note Element: 310.
     methods.

 -- Function: xml.etree.ElementTree.dump (elem)

     Writes an element tree or element structure to sys.stdout.  This
     function should be used for debugging only.

     The exact output format is implementation dependent.  In this
     version, it’s written as an ordinary XML file.

     'elem' is an element tree or an individual element.

     Changed in version 3.8: The ‘dump()’ function now preserves the
     attribute order specified by the user.

 -- Function: xml.etree.ElementTree.fromstring (text, parser=None)

     Parses an XML section from a string constant.  Same as *note XML():
     39d6.  'text' is a string containing XML data.  'parser' is an
     optional parser instance.  If not given, the standard *note
     XMLParser: a62. parser is used.  Returns an *note Element: 310.
     instance.

 -- Function: xml.etree.ElementTree.fromstringlist (sequence,
          parser=None)

     Parses an XML document from a sequence of string fragments.
     'sequence' is a list or other sequence containing XML data
     fragments.  'parser' is an optional parser instance.  If not given,
     the standard *note XMLParser: a62. parser is used.  Returns an
     *note Element: 310. instance.

     Added in version 3.2.

 -- Function: xml.etree.ElementTree.indent (tree, space=' ', level=0)

     Appends whitespace to the subtree to indent the tree visually.
     This can be used to generate pretty-printed XML output.  'tree' can
     be an Element or ElementTree.  'space' is the whitespace string
     that will be inserted for each indentation level, two space
     characters by default.  For indenting partial subtrees inside of an
     already indented tree, pass the initial indentation level as
     'level'.

     Added in version 3.9.

 -- Function: xml.etree.ElementTree.iselement (element)

     Check if an object appears to be a valid element object.  'element'
     is an element instance.  Return ‘True’ if this is an element
     object.

 -- Function: xml.etree.ElementTree.iterparse (source, events=None,
          parser=None)

     Parses an XML section into an element tree incrementally, and
     reports what’s going on to the user.  'source' is a filename or
     *note file object: 1208. containing XML data.  'events' is a
     sequence of events to report back.  The supported events are the
     strings ‘"start"’, ‘"end"’, ‘"comment"’, ‘"pi"’, ‘"start-ns"’ and
     ‘"end-ns"’ (the “ns” events are used to get detailed namespace
     information).  If 'events' is omitted, only ‘"end"’ events are
     reported.  'parser' is an optional parser instance.  If not given,
     the standard *note XMLParser: a62. parser is used.  'parser' must
     be a subclass of ‘XMLParser’ and can only use the default *note
     TreeBuilder: a63. as a target.  Returns an *note iterator: 1ac.
     providing ‘(event, elem)’ pairs; it has a ‘root’ attribute that
     references the root element of the resulting XML tree once 'source'
     is fully read.  The iterator has the ‘close()’ method that closes
     the internal file object if 'source' is a filename.

     Note that while ‘iterparse()’ builds the tree incrementally, it
     issues blocking reads on 'source' (or the file it names).  As such,
     it’s unsuitable for applications where blocking reads can’t be
     made.  For fully non-blocking parsing, see *note XMLPullParser:
     102e.

          Note: ‘iterparse()’ only guarantees that it has seen the “>”
          character of a starting tag when it emits a “start” event, so
          the attributes are defined, but the contents of the text and
          tail attributes are undefined at that point.  The same applies
          to the element children; they may or may not be present.

          If you need a fully populated element, look for “end” events
          instead.

     Deprecated since version 3.4: The 'parser' argument.

     Changed in version 3.8: The ‘comment’ and ‘pi’ events were added.

     Changed in version 3.13: Added the ‘close()’ method.

 -- Function: xml.etree.ElementTree.parse (source, parser=None)

     Parses an XML section into an element tree.  'source' is a filename
     or file object containing XML data.  'parser' is an optional parser
     instance.  If not given, the standard *note XMLParser: a62. parser
     is used.  Returns an *note ElementTree: 958. instance.

 -- Function: xml.etree.ElementTree.ProcessingInstruction (target,
          text=None)

     PI element factory.  This factory function creates a special
     element that will be serialized as an XML processing instruction.
     'target' is a string containing the PI target.  'text' is a string
     containing the PI contents, if given.  Returns an element instance,
     representing a processing instruction.

     Note that *note XMLParser: a62. skips over processing instructions
     in the input instead of creating PI objects for them.  An *note
     ElementTree: 958. will only contain processing instruction nodes if
     they have been inserted into to the tree using one of the *note
     Element: 310. methods.

 -- Function: xml.etree.ElementTree.register_namespace (prefix, uri)

     Registers a namespace prefix.  The registry is global, and any
     existing mapping for either the given prefix or the namespace URI
     will be removed.  'prefix' is a namespace prefix.  'uri' is a
     namespace uri.  Tags and attributes in this namespace will be
     serialized with the given prefix, if at all possible.

     Added in version 3.2.

 -- Function: xml.etree.ElementTree.SubElement (parent, tag, attrib={},
          **extra)

     Subelement factory.  This function creates an element instance, and
     appends it to an existing element.

     The element name, attribute names, and attribute values can be
     either bytestrings or Unicode strings.  'parent' is the parent
     element.  'tag' is the subelement name.  'attrib' is an optional
     dictionary, containing element attributes.  'extra' contains
     additional attributes, given as keyword arguments.  Returns an
     element instance.

 -- Function: xml.etree.ElementTree.tostring (element,
          encoding='us-ascii', method='xml', *, xml_declaration=None,
          default_namespace=None, short_empty_elements=True)

     Generates a string representation of an XML element, including all
     subelements.  'element' is an *note Element: 310. instance.
     'encoding' (2) is the output encoding (default is US-ASCII). Use
     ‘encoding="unicode"’ to generate a Unicode string (otherwise, a
     bytestring is generated).  'method' is either ‘"xml"’, ‘"html"’ or
     ‘"text"’ (default is ‘"xml"’).  'xml_declaration',
     'default_namespace' and 'short_empty_elements' has the same meaning
     as in *note ElementTree.write(): aaa.  Returns an (optionally)
     encoded string containing the XML data.

     Changed in version 3.4: Added the 'short_empty_elements' parameter.

     Changed in version 3.8: Added the 'xml_declaration' and
     'default_namespace' parameters.

     Changed in version 3.8: The ‘tostring()’ function now preserves the
     attribute order specified by the user.

 -- Function: xml.etree.ElementTree.tostringlist (element,
          encoding='us-ascii', method='xml', *, xml_declaration=None,
          default_namespace=None, short_empty_elements=True)

     Generates a string representation of an XML element, including all
     subelements.  'element' is an *note Element: 310. instance.
     'encoding' (3) is the output encoding (default is US-ASCII). Use
     ‘encoding="unicode"’ to generate a Unicode string (otherwise, a
     bytestring is generated).  'method' is either ‘"xml"’, ‘"html"’ or
     ‘"text"’ (default is ‘"xml"’).  'xml_declaration',
     'default_namespace' and 'short_empty_elements' has the same meaning
     as in *note ElementTree.write(): aaa.  Returns a list of
     (optionally) encoded strings containing the XML data.  It does not
     guarantee any specific sequence, except that
     ‘b"".join(tostringlist(element)) == tostring(element)’.

     Added in version 3.2.

     Changed in version 3.4: Added the 'short_empty_elements' parameter.

     Changed in version 3.8: Added the 'xml_declaration' and
     'default_namespace' parameters.

     Changed in version 3.8: The ‘tostringlist()’ function now preserves
     the attribute order specified by the user.

 -- Function: xml.etree.ElementTree.XML (text, parser=None)

     Parses an XML section from a string constant.  This function can be
     used to embed “XML literals” in Python code.  'text' is a string
     containing XML data.  'parser' is an optional parser instance.  If
     not given, the standard *note XMLParser: a62. parser is used.
     Returns an *note Element: 310. instance.

 -- Function: xml.etree.ElementTree.XMLID (text, parser=None)

     Parses an XML section from a string constant, and also returns a
     dictionary which maps from element id:s to elements.  'text' is a
     string containing XML data.  'parser' is an optional parser
     instance.  If not given, the standard *note XMLParser: a62. parser
     is used.  Returns a tuple containing an *note Element: 310.
     instance and a dictionary.

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/xml-c14n2/

   (2) The encoding string included in XML output should conform to the
appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.

   (3) The encoding string included in XML output should conform to the
appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.


File: python.info,  Node: XInclude support,  Next: Reference<5>,  Prev: Reference<4>,  Up: xml etree ElementTree — The ElementTree XML API

5.21.5.14 XInclude support
..........................

This module provides limited support for XInclude directives(1), via the
*note xml.etree.ElementInclude: 124. helper module.  This module can be
used to insert subtrees and text strings into element trees, based on
information in the tree.

* Menu:

* Example: Example<9>.

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/xinclude/


File: python.info,  Node: Example<9>,  Up: XInclude support

5.21.5.15 Example
.................

Here’s an example that demonstrates use of the XInclude module.  To
include an XML document in the current document, use the
‘{http://www.w3.org/2001/XInclude}include’ element and set the 'parse'
attribute to ‘"xml"’, and use the 'href' attribute to specify the
document to include.

     <?xml version="1.0"?>
     <document xmlns:xi="http://www.w3.org/2001/XInclude">
       <xi:include href="source.xml" parse="xml" />
     </document>

By default, the 'href' attribute is treated as a file name.  You can use
custom loaders to override this behaviour.  Also note that the standard
helper does not support XPointer syntax.

To process this file, load it as usual, and pass the root element to the
‘xml.etree.ElementTree’ module:

     from xml.etree import ElementTree, ElementInclude

     tree = ElementTree.parse("document.xml")
     root = tree.getroot()

     ElementInclude.include(root)

The ElementInclude module replaces the
‘{http://www.w3.org/2001/XInclude}include’ element with the root element
from the 'source.xml' document.  The result might look something like
this:

     <document xmlns:xi="http://www.w3.org/2001/XInclude">
       <para>This is a paragraph.</para>
     </document>

If the 'parse' attribute is omitted, it defaults to “xml”.  The href
attribute is required.

To include a text document, use the
‘{http://www.w3.org/2001/XInclude}include’ element, and set the 'parse'
attribute to “text”:

     <?xml version="1.0"?>
     <document xmlns:xi="http://www.w3.org/2001/XInclude">
       Copyright (c) <xi:include href="year.txt" parse="text" />.
     </document>

The result might look something like:

     <document xmlns:xi="http://www.w3.org/2001/XInclude">
       Copyright (c) 2003.
     </document>


File: python.info,  Node: Reference<5>,  Prev: XInclude support,  Up: xml etree ElementTree — The ElementTree XML API

5.21.5.16 Reference
...................

* Menu:

* Functions: Functions<10>.
* Element Objects::
* ElementTree Objects::
* QName Objects::
* TreeBuilder Objects::
* XMLParser Objects::
* XMLPullParser Objects::
* Exceptions: Exceptions<19>.


File: python.info,  Node: Functions<10>,  Next: Element Objects,  Up: Reference<5>

5.21.5.17 Functions
...................

 -- Function: xml.etree.ElementInclude.default_loader (href, parse,
          encoding=None)

     Default loader.  This default loader reads an included resource
     from disk.  'href' is a URL. 'parse' is for parse mode either “xml”
     or “text”.  'encoding' is an optional text encoding.  If not given,
     encoding is ‘utf-8’.  Returns the expanded resource.  If the parse
     mode is ‘"xml"’, this is an *note Element: 310. instance.  If the
     parse mode is ‘"text"’, this is a string.  If the loader fails, it
     can return ‘None’ or raise an exception.

 -- Function: xml.etree.ElementInclude.include (elem, loader=None,
          base_url=None, max_depth=6)

     This function expands XInclude directives in-place in tree pointed
     by 'elem'.  'elem' is either the root *note Element: 310. or an
     *note ElementTree: 958. instance to find such element.  'loader' is
     an optional resource loader.  If omitted, it defaults to *note
     default_loader(): 39e2.  If given, it should be a callable that
     implements the same interface as ‘default_loader()’.  'base_url' is
     base URL of the original file, to resolve relative include file
     references.  'max_depth' is the maximum number of recursive
     inclusions.  Limited to reduce the risk of malicious content
     explosion.  Pass ‘None’ to disable the limitation.

     Changed in version 3.9: Added the 'base_url' and 'max_depth'
     parameters.


File: python.info,  Node: Element Objects,  Next: ElementTree Objects,  Prev: Functions<10>,  Up: Reference<5>

5.21.5.18 Element Objects
.........................

 -- Class: xml.etree.ElementTree.Element (tag, attrib={}, **extra)

     Element class.  This class defines the Element interface, and
     provides a reference implementation of this interface.

     The element name, attribute names, and attribute values can be
     either bytestrings or Unicode strings.  'tag' is the element name.
     'attrib' is an optional dictionary, containing element attributes.
     'extra' contains additional attributes, given as keyword arguments.

      -- Attribute: tag

          A string identifying what kind of data this element represents
          (the element type, in other words).

      -- Attribute: text
      -- Attribute: tail

          These attributes can be used to hold additional data
          associated with the element.  Their values are usually strings
          but may be any application-specific object.  If the element is
          created from an XML file, the 'text' attribute holds either
          the text between the element’s start tag and its first child
          or end tag, or ‘None’, and the 'tail' attribute holds either
          the text between the element’s end tag and the next tag, or
          ‘None’.  For the XML data

               <a><b>1<c>2<d/>3</c></b>4</a>

          the 'a' element has ‘None’ for both 'text' and 'tail'
          attributes, the 'b' element has 'text' ‘"1"’ and 'tail' ‘"4"’,
          the 'c' element has 'text' ‘"2"’ and 'tail' ‘None’, and the
          'd' element has 'text' ‘None’ and 'tail' ‘"3"’.

          To collect the inner text of an element, see *note itertext():
          121a, for example ‘"".join(element.itertext())’.

          Applications may store arbitrary objects in these attributes.

      -- Attribute: attrib

          A dictionary containing the element’s attributes.  Note that
          while the 'attrib' value is always a real mutable Python
          dictionary, an ElementTree implementation may choose to use
          another internal representation, and create the dictionary
          only if someone asks for it.  To take advantage of such
          implementations, use the dictionary methods below whenever
          possible.

     The following dictionary-like methods work on the element
     attributes.

      -- Method: clear ()

          Resets an element.  This function removes all subelements,
          clears all attributes, and sets the text and tail attributes
          to ‘None’.

      -- Method: get (key, default=None)

          Gets the element attribute named 'key'.

          Returns the attribute value, or 'default' if the attribute was
          not found.

      -- Method: items ()

          Returns the element attributes as a sequence of (name, value)
          pairs.  The attributes are returned in an arbitrary order.

      -- Method: keys ()

          Returns the elements attribute names as a list.  The names are
          returned in an arbitrary order.

      -- Method: set (key, value)

          Set the attribute 'key' on the element to 'value'.

     The following methods work on the element’s children (subelements).

      -- Method: append (subelement)

          Adds the element 'subelement' to the end of this element’s
          internal list of subelements.  Raises *note TypeError: 2c3. if
          'subelement' is not an ‘Element’.

      -- Method: extend (subelements)

          Appends 'subelements' from an iterable of elements.  Raises
          *note TypeError: 2c3. if a subelement is not an ‘Element’.

          Added in version 3.2.

      -- Method: find (match, namespaces=None)

          Finds the first subelement matching 'match'.  'match' may be a
          tag name or a *note path: bcb.  Returns an element instance or
          ‘None’.  'namespaces' is an optional mapping from namespace
          prefix to full name.  Pass ‘''’ as prefix to move all
          unprefixed tag names in the expression into the given
          namespace.

      -- Method: findall (match, namespaces=None)

          Finds all matching subelements, by tag name or *note path:
          bcb.  Returns a list containing all matching elements in
          document order.  'namespaces' is an optional mapping from
          namespace prefix to full name.  Pass ‘''’ as prefix to move
          all unprefixed tag names in the expression into the given
          namespace.

      -- Method: findtext (match, default=None, namespaces=None)

          Finds text for the first subelement matching 'match'.  'match'
          may be a tag name or a *note path: bcb.  Returns the text
          content of the first matching element, or 'default' if no
          element was found.  Note that if the matching element has no
          text content an empty string is returned.  'namespaces' is an
          optional mapping from namespace prefix to full name.  Pass
          ‘''’ as prefix to move all unprefixed tag names in the
          expression into the given namespace.

      -- Method: insert (index, subelement)

          Inserts 'subelement' at the given position in this element.
          Raises *note TypeError: 2c3. if 'subelement' is not an
          ‘Element’.

      -- Method: iter (tag=None)

          Creates a tree *note iterator: 1ac. with the current element
          as the root.  The iterator iterates over this element and all
          elements below it, in document (depth first) order.  If 'tag'
          is not ‘None’ or ‘'*'’, only elements whose tag equals 'tag'
          are returned from the iterator.  If the tree structure is
          modified during iteration, the result is undefined.

          Added in version 3.2.

      -- Method: iterfind (match, namespaces=None)

          Finds all matching subelements, by tag name or *note path:
          bcb.  Returns an iterable yielding all matching elements in
          document order.  'namespaces' is an optional mapping from
          namespace prefix to full name.

          Added in version 3.2.

      -- Method: itertext ()

          Creates a text iterator.  The iterator loops over this element
          and all subelements, in document order, and returns all inner
          text.

          Added in version 3.2.

      -- Method: makeelement (tag, attrib)

          Creates a new element object of the same type as this element.
          Do not call this method, use the *note SubElement(): 39cc.
          factory function instead.

      -- Method: remove (subelement)

          Removes 'subelement' from the element.  Unlike the find*
          methods this method compares elements based on the instance
          identity, not on tag value or contents.

     ‘Element’ objects also support the following sequence type methods
     for working with subelements: *note __delitem__(): 1314, *note
     __getitem__(): 283, *note __setitem__(): 1313, *note __len__():
     15da.

     Caution: Elements with no subelements will test as ‘False’.  In a
     future release of Python, all elements will test as ‘True’
     regardless of whether subelements exist.  Instead, prefer explicit
     ‘len(elem)’ or ‘elem is not None’ tests.:

          element = root.find('foo')

          if not element:  # careful!
              print("element not found, or element has no subelements")

          if element is None:
              print("element not found")

     Changed in version 3.12: Testing the truth value of an Element
     emits *note DeprecationWarning: 1a5.

     Prior to Python 3.8, the serialisation order of the XML attributes
     of elements was artificially made predictable by sorting the
     attributes by their name.  Based on the now guaranteed ordering of
     dicts, this arbitrary reordering was removed in Python 3.8 to
     preserve the order in which attributes were originally parsed or
     created by user code.

     In general, user code should try not to depend on a specific
     ordering of attributes, given that the XML Information Set(1)
     explicitly excludes the attribute order from conveying information.
     Code should be prepared to deal with any ordering on input.  In
     cases where deterministic XML output is required, e.g.  for
     cryptographic signing or test data sets, canonical serialisation is
     available with the *note canonicalize(): a61. function.

     In cases where canonical output is not applicable but a specific
     attribute order is still desirable on output, code should aim for
     creating the attributes directly in the desired order, to avoid
     perceptual mismatches for readers of the code.  In cases where this
     is difficult to achieve, a recipe like the following can be applied
     prior to serialisation to enforce an order independently from the
     Element creation:

          def reorder_attributes(root):
              for el in root.iter():
                  attrib = el.attrib
                  if len(attrib) > 1:
                      # adjust attribute order, e.g. by sorting
                      attribs = sorted(attrib.items())
                      attrib.clear()
                      attrib.update(attribs)

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/xml-infoset/


File: python.info,  Node: ElementTree Objects,  Next: QName Objects,  Prev: Element Objects,  Up: Reference<5>

5.21.5.19 ElementTree Objects
.............................

 -- Class: xml.etree.ElementTree.ElementTree (element=None, file=None)

     ElementTree wrapper class.  This class represents an entire element
     hierarchy, and adds some extra support for serialization to and
     from standard XML.

     'element' is the root element.  The tree is initialized with the
     contents of the XML 'file' if given.

      -- Method: _setroot (element)

          Replaces the root element for this tree.  This discards the
          current contents of the tree, and replaces it with the given
          element.  Use with care.  'element' is an element instance.

      -- Method: find (match, namespaces=None)

          Same as *note Element.find(): 166a, starting at the root of
          the tree.

      -- Method: findall (match, namespaces=None)

          Same as *note Element.findall(): 166c, starting at the root of
          the tree.

      -- Method: findtext (match, default=None, namespaces=None)

          Same as *note Element.findtext(): 166b, starting at the root
          of the tree.

      -- Method: getroot ()

          Returns the root element for this tree.

      -- Method: iter (tag=None)

          Creates and returns a tree iterator for the root element.  The
          iterator loops over all elements in this tree, in section
          order.  'tag' is the tag to look for (default is to return all
          elements).

      -- Method: iterfind (match, namespaces=None)

          Same as *note Element.iterfind(): 1219, starting at the root
          of the tree.

          Added in version 3.2.

      -- Method: parse (source, parser=None)

          Loads an external XML section into this element tree.
          'source' is a file name or *note file object: 1208.  'parser'
          is an optional parser instance.  If not given, the standard
          *note XMLParser: a62. parser is used.  Returns the section
          root element.

      -- Method: write (file, encoding='us-ascii', xml_declaration=None,
               default_namespace=None, method='xml', *,
               short_empty_elements=True)

          Writes the element tree to a file, as XML. 'file' is a file
          name, or a *note file object: 1208. opened for writing.
          'encoding' (1) is the output encoding (default is US-ASCII).
          'xml_declaration' controls if an XML declaration should be
          added to the file.  Use ‘False’ for never, ‘True’ for always,
          ‘None’ for only if not US-ASCII or UTF-8 or Unicode (default
          is ‘None’).  'default_namespace' sets the default XML
          namespace (for “xmlns”).  'method' is either ‘"xml"’, ‘"html"’
          or ‘"text"’ (default is ‘"xml"’).  The keyword-only
          'short_empty_elements' parameter controls the formatting of
          elements that contain no content.  If ‘True’ (the default),
          they are emitted as a single self-closed tag, otherwise they
          are emitted as a pair of start/end tags.

          The output is either a string (*note str: 44f.) or binary
          (*note bytes: 1c2.).  This is controlled by the 'encoding'
          argument.  If 'encoding' is ‘"unicode"’, the output is a
          string; otherwise, it’s binary.  Note that this may conflict
          with the type of 'file' if it’s an open *note file object:
          1208.; make sure you do not try to write a string to a binary
          stream and vice versa.

          Changed in version 3.4: Added the 'short_empty_elements'
          parameter.

          Changed in version 3.8: The ‘write()’ method now preserves the
          attribute order specified by the user.

This is the XML file that is going to be manipulated:

     <html>
         <head>
             <title>Example page</title>
         </head>
         <body>
             <p>Moved to <a href="http://example.org/">example.org</a>
             or <a href="http://example.com/">example.com</a>.</p>
         </body>
     </html>

Example of changing the attribute “target” of every link in first
paragraph:

     >>> from xml.etree.ElementTree import ElementTree
     >>> tree = ElementTree()
     >>> tree.parse("index.xhtml")
     <Element 'html' at 0xb77e6fac>
     >>> p = tree.find("body/p")     # Finds first occurrence of tag p in body
     >>> p
     <Element 'p' at 0xb77ec26c>
     >>> links = list(p.iter("a"))   # Returns list of all links
     >>> links
     [<Element 'a' at 0xb77ec2ac>, <Element 'a' at 0xb77ec1cc>]
     >>> for i in links:             # Iterates through all found links
     ...     i.attrib["target"] = "blank"
     ...
     >>> tree.write("output.xhtml")

   ---------- Footnotes ----------

   (1) The encoding string included in XML output should conform to the
appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.


File: python.info,  Node: QName Objects,  Next: TreeBuilder Objects,  Prev: ElementTree Objects,  Up: Reference<5>

5.21.5.20 QName Objects
.......................

 -- Class: xml.etree.ElementTree.QName (text_or_uri, tag=None)

     QName wrapper.  This can be used to wrap a QName attribute value,
     in order to get proper namespace handling on output.  'text_or_uri'
     is a string containing the QName value, in the form {uri}local, or,
     if the tag argument is given, the URI part of a QName.  If 'tag' is
     given, the first argument is interpreted as a URI, and this
     argument is interpreted as a local name.  ‘QName’ instances are
     opaque.


File: python.info,  Node: TreeBuilder Objects,  Next: XMLParser Objects,  Prev: QName Objects,  Up: Reference<5>

5.21.5.21 TreeBuilder Objects
.............................

 -- Class: xml.etree.ElementTree.TreeBuilder (element_factory=None, *,
          comment_factory=None, pi_factory=None, insert_comments=False,
          insert_pis=False)

     Generic element structure builder.  This builder converts a
     sequence of start, data, end, comment and pi method calls to a
     well-formed element structure.  You can use this class to build an
     element structure using a custom XML parser, or a parser for some
     other XML-like format.

     'element_factory', when given, must be a callable accepting two
     positional arguments: a tag and a dict of attributes.  It is
     expected to return a new element instance.

     The 'comment_factory' and 'pi_factory' functions, when given,
     should behave like the *note Comment(): 39d4. and *note
     ProcessingInstruction(): 39da. functions to create comments and
     processing instructions.  When not given, the default factories
     will be used.  When 'insert_comments' and/or 'insert_pis' is true,
     comments/pis will be inserted into the tree if they appear within
     the root element (but not outside of it).

      -- Method: close ()

          Flushes the builder buffers, and returns the toplevel document
          element.  Returns an *note Element: 310. instance.

      -- Method: data (data)

          Adds text to the current element.  'data' is a string.  This
          should be either a bytestring, or a Unicode string.

      -- Method: end (tag)

          Closes the current element.  'tag' is the element name.
          Returns the closed element.

      -- Method: start (tag, attrs)

          Opens a new element.  'tag' is the element name.  'attrs' is a
          dictionary containing element attributes.  Returns the opened
          element.

      -- Method: comment (text)

          Creates a comment with the given 'text'.  If ‘insert_comments’
          is true, this will also add it to the tree.

          Added in version 3.8.

      -- Method: pi (target, text)

          Creates a process instruction with the given 'target' name and
          'text'.  If ‘insert_pis’ is true, this will also add it to the
          tree.

          Added in version 3.8.

     In addition, a custom ‘TreeBuilder’ object can provide the
     following methods:

      -- Method: doctype (name, pubid, system)

          Handles a doctype declaration.  'name' is the doctype name.
          'pubid' is the public identifier.  'system' is the system
          identifier.  This method does not exist on the default
          ‘TreeBuilder’ class.

          Added in version 3.2.

      -- Method: start_ns (prefix, uri)

          Is called whenever the parser encounters a new namespace
          declaration, before the ‘start()’ callback for the opening
          element that defines it.  'prefix' is ‘''’ for the default
          namespace and the declared namespace prefix name otherwise.
          'uri' is the namespace URI.

          Added in version 3.8.

      -- Method: end_ns (prefix)

          Is called after the ‘end()’ callback of an element that
          declared a namespace prefix mapping, with the name of the
          'prefix' that went out of scope.

          Added in version 3.8.

 -- Class: xml.etree.ElementTree.C14NWriterTarget (write, *,
          with_comments=False, strip_text=False, rewrite_prefixes=False,
          qname_aware_tags=None, qname_aware_attrs=None,
          exclude_attrs=None, exclude_tags=None)

     A C14N 2.0(1) writer.  Arguments are the same as for the *note
     canonicalize(): a61. function.  This class does not build a tree
     but translates the callback events directly into a serialised form
     using the 'write' function.

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/xml-c14n2/


File: python.info,  Node: XMLParser Objects,  Next: XMLPullParser Objects,  Prev: TreeBuilder Objects,  Up: Reference<5>

5.21.5.22 XMLParser Objects
...........................

 -- Class: xml.etree.ElementTree.XMLParser (*, target=None,
          encoding=None)

     This class is the low-level building block of the module.  It uses
     *note xml.parsers.expat: 126. for efficient, event-based parsing of
     XML. It can be fed XML data incrementally with the *note feed():
     3a05. method, and parsing events are translated to a push API - by
     invoking callbacks on the 'target' object.  If 'target' is omitted,
     the standard *note TreeBuilder: a63. is used.  If 'encoding' (1) is
     given, the value overrides the encoding specified in the XML file.

     Changed in version 3.8: Parameters are now *note keyword-only: 2a5.
     The 'html' argument is no longer supported.

      -- Method: close ()

          Finishes feeding data to the parser.  Returns the result of
          calling the ‘close()’ method of the 'target' passed during
          construction; by default, this is the toplevel document
          element.

      -- Method: feed (data)

          Feeds data to the parser.  'data' is encoded data.

      -- Method: flush ()

          Triggers parsing of any previously fed unparsed data, which
          can be used to ensure more immediate feedback, in particular
          with Expat >=2.6.0.  The implementation of ‘flush()’
          temporarily disables reparse deferral with Expat (if currently
          enabled) and triggers a reparse.  Disabling reparse deferral
          has security consequences; please see *note
          xml.parsers.expat.xmlparser.SetReparseDeferralEnabled(): 272.
          for details.

          Note that ‘flush()’ has been backported to some prior releases
          of CPython as a security fix.  Check for availability of
          ‘flush()’ using *note hasattr(): 4d5. if used in code running
          across a variety of Python versions.

          Added in version 3.13.

     *note XMLParser.feed(): 3a05. calls 'target"s ‘start(tag,
     attrs_dict)’ method for each opening tag, its ‘end(tag)’ method for
     each closing tag, and data is processed by method ‘data(data)’.
     For further supported callback methods, see the *note TreeBuilder:
     a63. class.  *note XMLParser.close(): 3a06. calls 'target"s method
     ‘close()’.  ‘XMLParser’ can be used not only for building a tree
     structure.  This is an example of counting the maximum depth of an
     XML file:

          >>> from xml.etree.ElementTree import XMLParser
          >>> class MaxDepth:                     # The target object of the parser
          ...     maxDepth = 0
          ...     depth = 0
          ...     def start(self, tag, attrib):   # Called for each opening tag.
          ...         self.depth += 1
          ...         if self.depth > self.maxDepth:
          ...             self.maxDepth = self.depth
          ...     def end(self, tag):             # Called for each closing tag.
          ...         self.depth -= 1
          ...     def data(self, data):
          ...         pass            # We do not need to do anything with data.
          ...     def close(self):    # Called when all data has been parsed.
          ...         return self.maxDepth
          ...
          >>> target = MaxDepth()
          >>> parser = XMLParser(target=target)
          >>> exampleXml = """
          ... <a>
          ...   <b>
          ...   </b>
          ...   <b>
          ...     <c>
          ...       <d>
          ...       </d>
          ...     </c>
          ...   </b>
          ... </a>"""
          >>> parser.feed(exampleXml)
          >>> parser.close()
          4

   ---------- Footnotes ----------

   (1) The encoding string included in XML output should conform to the
appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.


File: python.info,  Node: XMLPullParser Objects,  Next: Exceptions<19>,  Prev: XMLParser Objects,  Up: Reference<5>

5.21.5.23 XMLPullParser Objects
...............................

 -- Class: xml.etree.ElementTree.XMLPullParser (events=None)

     A pull parser suitable for non-blocking applications.  Its
     input-side API is similar to that of *note XMLParser: a62, but
     instead of pushing calls to a callback target, ‘XMLPullParser’
     collects an internal list of parsing events and lets the user read
     from it.  'events' is a sequence of events to report back.  The
     supported events are the strings ‘"start"’, ‘"end"’, ‘"comment"’,
     ‘"pi"’, ‘"start-ns"’ and ‘"end-ns"’ (the “ns” events are used to
     get detailed namespace information).  If 'events' is omitted, only
     ‘"end"’ events are reported.

      -- Method: feed (data)

          Feed the given bytes data to the parser.

      -- Method: flush ()

          Triggers parsing of any previously fed unparsed data, which
          can be used to ensure more immediate feedback, in particular
          with Expat >=2.6.0.  The implementation of ‘flush()’
          temporarily disables reparse deferral with Expat (if currently
          enabled) and triggers a reparse.  Disabling reparse deferral
          has security consequences; please see *note
          xml.parsers.expat.xmlparser.SetReparseDeferralEnabled(): 272.
          for details.

          Note that ‘flush()’ has been backported to some prior releases
          of CPython as a security fix.  Check for availability of
          ‘flush()’ using *note hasattr(): 4d5. if used in code running
          across a variety of Python versions.

          Added in version 3.13.

      -- Method: close ()

          Signal the parser that the data stream is terminated.  Unlike
          *note XMLParser.close(): 3a06, this method always returns
          *note None: 678.  Any events not yet retrieved when the parser
          is closed can still be read with *note read_events(): 39c4.

      -- Method: read_events ()

          Return an iterator over the events which have been encountered
          in the data fed to the parser.  The iterator yields ‘(event,
          elem)’ pairs, where 'event' is a string representing the type
          of event (e.g.  ‘"end"’) and 'elem' is the encountered *note
          Element: 310. object, or other context value as follows.

             * ‘start’, ‘end’: the current Element.

             * ‘comment’, ‘pi’: the current comment / processing
               instruction

             * ‘start-ns’: a tuple ‘(prefix, uri)’ naming the declared
               namespace mapping.

             * ‘end-ns’: *note None: 678. (this may change in a future
               version)

          Events provided in a previous call to ‘read_events()’ will not
          be yielded again.  Events are consumed from the internal queue
          only when they are retrieved from the iterator, so multiple
          readers iterating in parallel over iterators obtained from
          ‘read_events()’ will have unpredictable results.

          Note: ‘XMLPullParser’ only guarantees that it has seen the “>”
          character of a starting tag when it emits a “start” event, so
          the attributes are defined, but the contents of the text and
          tail attributes are undefined at that point.  The same applies
          to the element children; they may or may not be present.

          If you need a fully populated element, look for “end” events
          instead.

     Added in version 3.4.

     Changed in version 3.8: The ‘comment’ and ‘pi’ events were added.


File: python.info,  Node: Exceptions<19>,  Prev: XMLPullParser Objects,  Up: Reference<5>

5.21.5.24 Exceptions
....................

 -- Class: xml.etree.ElementTree.ParseError

     XML parse error, raised by the various parsing methods in this
     module when parsing fails.  The string representation of an
     instance of this exception will contain a user-friendly error
     message.  In addition, it will have the following attributes
     available:

      -- Attribute: code

          A numeric error code from the expat parser.  See the
          documentation of *note xml.parsers.expat: 126. for the list of
          error codes and their meanings.

      -- Attribute: position

          A tuple of 'line', 'column' numbers, specifying where the
          error occurred.


File: python.info,  Node: xml dom — The Document Object Model API,  Next: xml dom minidom — Minimal DOM implementation,  Prev: xml etree ElementTree — The ElementTree XML API,  Up: Structured Markup Processing Tools

5.21.6 ‘xml.dom’ — The Document Object Model API
------------------------------------------------

'Source code:' Lib/xml/dom/__init__.py(1)

__________________________________________________________________

The Document Object Model, or “DOM,” is a cross-language API from the
World Wide Web Consortium (W3C) for accessing and modifying XML
documents.  A DOM implementation presents an XML document as a tree
structure, or allows client code to build such a structure from scratch.
It then gives access to the structure through a set of objects which
provided well-known interfaces.

The DOM is extremely useful for random-access applications.  SAX only
allows you a view of one bit of the document at a time.  If you are
looking at one SAX element, you have no access to another.  If you are
looking at a text node, you have no access to a containing element.
When you write a SAX application, you need to keep track of your
program’s position in the document somewhere in your own code.  SAX does
not do it for you.  Also, if you need to look ahead in the XML document,
you are just out of luck.

Some applications are simply impossible in an event driven model with no
access to a tree.  Of course you could build some sort of tree yourself
in SAX events, but the DOM allows you to avoid writing that code.  The
DOM is a standard tree representation for XML data.

The Document Object Model is being defined by the W3C in stages, or
“levels” in their terminology.  The Python mapping of the API is
substantially based on the DOM Level 2 recommendation.

DOM applications typically start by parsing some XML into a DOM. How
this is accomplished is not covered at all by DOM Level 1, and Level 2
provides only limited improvements: There is a ‘DOMImplementation’
object class which provides access to ‘Document’ creation methods, but
no way to access an XML reader/parser/Document builder in an
implementation-independent way.  There is also no well-defined way to
access these methods without an existing ‘Document’ object.  In Python,
each DOM implementation will provide a function *note
getDOMImplementation(): 3a10.  DOM Level 3 adds a Load/Store
specification, which defines an interface to the reader, but this is not
yet available in the Python standard library.

Once you have a DOM document object, you can access the parts of your
XML document through its properties and methods.  These properties are
defined in the DOM specification; this portion of the reference manual
describes the interpretation of the specification in Python.

The specification provided by the W3C defines the DOM API for Java,
ECMAScript, and OMG IDL. The Python mapping defined here is based in
large part on the IDL version of the specification, but strict
compliance is not required (though implementations are free to support
the strict mapping from IDL). See section *note Conformance: 3a11. for a
detailed discussion of mapping requirements.

See also
........

Document Object Model (DOM) Level 2 Specification(2)

     The W3C recommendation upon which the Python DOM API is based.

Document Object Model (DOM) Level 1 Specification(3)

     The W3C recommendation for the DOM supported by *note
     xml.dom.minidom: 122.

Python Language Mapping Specification(4)

     This specifies the mapping from OMG IDL to Python.

* Menu:

* Module Contents: Module Contents<3>.
* Objects in the DOM::
* Conformance::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/dom/__init__.py

   (2) https://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/

   (3) https://www.w3.org/TR/REC-DOM-Level-1/

   (4) https://www.omg.org/spec/PYTH/1.2/PDF


File: python.info,  Node: Module Contents<3>,  Next: Objects in the DOM,  Up: xml dom — The Document Object Model API

5.21.6.1 Module Contents
........................

The ‘xml.dom’ contains the following functions:

 -- Function: xml.dom.registerDOMImplementation (name, factory)

     Register the 'factory' function with the name 'name'.  The factory
     function should return an object which implements the
     ‘DOMImplementation’ interface.  The factory function can return the
     same object every time, or a new one for each call, as appropriate
     for the specific implementation (e.g.  if that implementation
     supports some customization).

 -- Function: xml.dom.getDOMImplementation (name=None, features=())

     Return a suitable DOM implementation.  The 'name' is either
     well-known, the module name of a DOM implementation, or ‘None’.  If
     it is not ‘None’, imports the corresponding module and returns a
     ‘DOMImplementation’ object if the import succeeds.  If no name is
     given, and if the environment variable ‘PYTHON_DOM’ is set, this
     variable is used to find the implementation.

     If name is not given, this examines the available implementations
     to find one with the required feature set.  If no implementation
     can be found, raise an *note ImportError: 41c.  The features list
     must be a sequence of ‘(feature, version)’ pairs which are passed
     to the ‘hasFeature()’ method on available ‘DOMImplementation’
     objects.

Some convenience constants are also provided:

 -- Data: xml.dom.EMPTY_NAMESPACE

     The value used to indicate that no namespace is associated with a
     node in the DOM. This is typically found as the ‘namespaceURI’ of a
     node, or used as the 'namespaceURI' parameter to a
     namespaces-specific method.

 -- Data: xml.dom.XML_NAMESPACE

     The namespace URI associated with the reserved prefix ‘xml’, as
     defined by Namespaces in XML(1) (section 4).

 -- Data: xml.dom.XMLNS_NAMESPACE

     The namespace URI for namespace declarations, as defined by
     Document Object Model (DOM) Level 2 Core Specification(2) (section
     1.1.8).

 -- Data: xml.dom.XHTML_NAMESPACE

     The URI of the XHTML namespace as defined by XHTML 1.0: The
     Extensible HyperText Markup Language(3) (section 3.1.1).

In addition, ‘xml.dom’ contains a base ‘Node’ class and the DOM
exception classes.  The ‘Node’ class provided by this module does not
implement any of the methods or attributes defined by the DOM
specification; concrete DOM implementations must provide those.  The
‘Node’ class provided as part of this module does provide the constants
used for the ‘nodeType’ attribute on concrete ‘Node’ objects; they are
located within the class rather than at the module level to conform with
the DOM specifications.

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/REC-xml-names/

   (2) https://www.w3.org/TR/DOM-Level-2-Core/core.html

   (3) https://www.w3.org/TR/xhtml1/


File: python.info,  Node: Objects in the DOM,  Next: Conformance,  Prev: Module Contents<3>,  Up: xml dom — The Document Object Model API

5.21.6.2 Objects in the DOM
...........................

The definitive documentation for the DOM is the DOM specification from
the W3C.

Note that DOM attributes may also be manipulated as nodes instead of as
simple strings.  It is fairly rare that you must do this, however, so
this usage is not yet documented.

Interface                            Section                                 Purpose
                                                                             
-------------------------------------------------------------------------------------------------------------------
                                                                             
‘DOMImplementation’                  *note DOMImplementation Objects: 3a1a.  Interface to the underlying
                                                                             implementation.
                                                                             
                                                                             
‘Node’                               *note Node Objects: 3a1b.               Base interface for most objects in
                                                                             a document.
                                                                             
                                                                             
‘NodeList’                           *note NodeList Objects: 2111.           Interface for a sequence of nodes.
                                                                             
                                                                             
‘DocumentType’                       *note DocumentType Objects: 3a1c.       Information about the declarations
                                                                             needed to process a document.
                                                                             
                                                                             
‘Document’                           *note Document Objects: 3a1d.           Object which represents an entire
                                                                             document.
                                                                             
                                                                             
‘Element’                            *note Element Objects: 3a1e.            Element nodes in the document
                                                                             hierarchy.
                                                                             
                                                                             
‘Attr’                               *note Attr Objects: 3a1f.               Attribute value nodes on element
                                                                             nodes.
                                                                             
                                                                             
‘Comment’                            *note Comment Objects: 3a20.            Representation of comments in the
                                                                             source document.
                                                                             
                                                                             
‘Text’                               *note Text and CDATASection Objects: 3a21.Nodes containing textual content
                                                                             from the document.
                                                                             
                                                                             
‘ProcessingInstruction’              *note ProcessingInstruction Objects: 3a22.Processing instruction
                                                                             representation.
                                                                             

An additional section describes the exceptions defined for working with
the DOM in Python.

* Menu:

* DOMImplementation Objects::
* Node Objects::
* NodeList Objects::
* DocumentType Objects::
* Document Objects::
* Element Objects: Element Objects<2>.
* Attr Objects::
* NamedNodeMap Objects::
* Comment Objects::
* Text and CDATASection Objects::
* ProcessingInstruction Objects::
* Exceptions: Exceptions<20>.


File: python.info,  Node: DOMImplementation Objects,  Next: Node Objects,  Up: Objects in the DOM

5.21.6.3 DOMImplementation Objects
..................................

The ‘DOMImplementation’ interface provides a way for applications to
determine the availability of particular features in the DOM they are
using.  DOM Level 2 added the ability to create new ‘Document’ and
‘DocumentType’ objects using the ‘DOMImplementation’ as well.

 -- Method: DOMImplementation.hasFeature (feature, version)

     Return ‘True’ if the feature identified by the pair of strings
     'feature' and 'version' is implemented.

 -- Method: DOMImplementation.createDocument (namespaceUri,
          qualifiedName, doctype)

     Return a new ‘Document’ object (the root of the DOM), with a child
     ‘Element’ object having the given 'namespaceUri' and
     'qualifiedName'.  The 'doctype' must be a ‘DocumentType’ object
     created by *note createDocumentType(): 3a26, or ‘None’.  In the
     Python DOM API, the first two arguments can also be ‘None’ in order
     to indicate that no ‘Element’ child is to be created.

 -- Method: DOMImplementation.createDocumentType (qualifiedName,
          publicId, systemId)

     Return a new ‘DocumentType’ object that encapsulates the given
     'qualifiedName', 'publicId', and 'systemId' strings, representing
     the information contained in an XML document type declaration.


File: python.info,  Node: Node Objects,  Next: NodeList Objects,  Prev: DOMImplementation Objects,  Up: Objects in the DOM

5.21.6.4 Node Objects
.....................

All of the components of an XML document are subclasses of ‘Node’.

 -- Attribute: Node.nodeType

     An integer representing the node type.  Symbolic constants for the
     types are on the ‘Node’ object: ‘ELEMENT_NODE’, ‘ATTRIBUTE_NODE’,
     ‘TEXT_NODE’, ‘CDATA_SECTION_NODE’, ‘ENTITY_NODE’,
     ‘PROCESSING_INSTRUCTION_NODE’, ‘COMMENT_NODE’, ‘DOCUMENT_NODE’,
     ‘DOCUMENT_TYPE_NODE’, ‘NOTATION_NODE’.  This is a read-only
     attribute.

 -- Attribute: Node.parentNode

     The parent of the current node, or ‘None’ for the document node.
     The value is always a ‘Node’ object or ‘None’.  For ‘Element’
     nodes, this will be the parent element, except for the root
     element, in which case it will be the ‘Document’ object.  For
     ‘Attr’ nodes, this is always ‘None’.  This is a read-only
     attribute.

 -- Attribute: Node.attributes

     A ‘NamedNodeMap’ of attribute objects.  Only elements have actual
     values for this; others provide ‘None’ for this attribute.  This is
     a read-only attribute.

 -- Attribute: Node.previousSibling

     The node that immediately precedes this one with the same parent.
     For instance the element with an end-tag that comes just before the
     'self' element’s start-tag.  Of course, XML documents are made up
     of more than just elements so the previous sibling could be text, a
     comment, or something else.  If this node is the first child of the
     parent, this attribute will be ‘None’.  This is a read-only
     attribute.

 -- Attribute: Node.nextSibling

     The node that immediately follows this one with the same parent.
     See also *note previousSibling: 3a2b.  If this is the last child of
     the parent, this attribute will be ‘None’.  This is a read-only
     attribute.

 -- Attribute: Node.childNodes

     A list of nodes contained within this node.  This is a read-only
     attribute.

 -- Attribute: Node.firstChild

     The first child of the node, if there are any, or ‘None’.  This is
     a read-only attribute.

 -- Attribute: Node.lastChild

     The last child of the node, if there are any, or ‘None’.  This is a
     read-only attribute.

 -- Attribute: Node.localName

     The part of the ‘tagName’ following the colon if there is one, else
     the entire ‘tagName’.  The value is a string.

 -- Attribute: Node.prefix

     The part of the ‘tagName’ preceding the colon if there is one, else
     the empty string.  The value is a string, or ‘None’.

 -- Attribute: Node.namespaceURI

     The namespace associated with the element name.  This will be a
     string or ‘None’.  This is a read-only attribute.

 -- Attribute: Node.nodeName

     This has a different meaning for each node type; see the DOM
     specification for details.  You can always get the information you
     would get here from another property such as the ‘tagName’ property
     for elements or the ‘name’ property for attributes.  For all node
     types, the value of this attribute will be either a string or
     ‘None’.  This is a read-only attribute.

 -- Attribute: Node.nodeValue

     This has a different meaning for each node type; see the DOM
     specification for details.  The situation is similar to that with
     *note nodeName: 3a33.  The value is a string or ‘None’.

 -- Method: Node.hasAttributes ()

     Return ‘True’ if the node has any attributes.

 -- Method: Node.hasChildNodes ()

     Return ‘True’ if the node has any child nodes.

 -- Method: Node.isSameNode (other)

     Return ‘True’ if 'other' refers to the same node as this node.
     This is especially useful for DOM implementations which use any
     sort of proxy architecture (because more than one object can refer
     to the same node).

          Note: This is based on a proposed DOM Level 3 API which is
          still in the “working draft” stage, but this particular
          interface appears uncontroversial.  Changes from the W3C will
          not necessarily affect this method in the Python DOM interface
          (though any new W3C API for this would also be supported).

 -- Method: Node.appendChild (newChild)

     Add a new child node to this node at the end of the list of
     children, returning 'newChild'.  If the node was already in the
     tree, it is removed first.

 -- Method: Node.insertBefore (newChild, refChild)

     Insert a new child node before an existing child.  It must be the
     case that 'refChild' is a child of this node; if not, *note
     ValueError: 202. is raised.  'newChild' is returned.  If 'refChild'
     is ‘None’, it inserts 'newChild' at the end of the children’s list.

 -- Method: Node.removeChild (oldChild)

     Remove a child node.  'oldChild' must be a child of this node; if
     not, *note ValueError: 202. is raised.  'oldChild' is returned on
     success.  If 'oldChild' will not be used further, its ‘unlink()’
     method should be called.

 -- Method: Node.replaceChild (newChild, oldChild)

     Replace an existing node with a new node.  It must be the case that
     'oldChild' is a child of this node; if not, *note ValueError: 202.
     is raised.

 -- Method: Node.normalize ()

     Join adjacent text nodes so that all stretches of text are stored
     as single ‘Text’ instances.  This simplifies processing text from a
     DOM tree for many applications.

 -- Method: Node.cloneNode (deep)

     Clone this node.  Setting 'deep' means to clone all child nodes as
     well.  This returns the clone.


File: python.info,  Node: NodeList Objects,  Next: DocumentType Objects,  Prev: Node Objects,  Up: Objects in the DOM

5.21.6.5 NodeList Objects
.........................

A ‘NodeList’ represents a sequence of nodes.  These objects are used in
two ways in the DOM Core recommendation: an ‘Element’ object provides
one as its list of child nodes, and the ‘getElementsByTagName()’ and
‘getElementsByTagNameNS()’ methods of ‘Node’ return objects with this
interface to represent query results.

The DOM Level 2 recommendation defines one method and one attribute for
these objects:

 -- Method: NodeList.item (i)

     Return the 'i'’th item from the sequence, if there is one, or
     ‘None’.  The index 'i' is not allowed to be less than zero or
     greater than or equal to the length of the sequence.

 -- Attribute: NodeList.length

     The number of nodes in the sequence.

In addition, the Python DOM interface requires that some additional
support is provided to allow ‘NodeList’ objects to be used as Python
sequences.  All ‘NodeList’ implementations must include support for
*note __len__(): 15da. and *note __getitem__(): 283.; this allows
iteration over the ‘NodeList’ in *note for: 2f2. statements and proper
support for the *note len(): 631. built-in function.

If a DOM implementation supports modification of the document, the
‘NodeList’ implementation must also support the *note __setitem__():
1313. and *note __delitem__(): 1314. methods.


File: python.info,  Node: DocumentType Objects,  Next: Document Objects,  Prev: NodeList Objects,  Up: Objects in the DOM

5.21.6.6 DocumentType Objects
.............................

Information about the notations and entities declared by a document
(including the external subset if the parser uses it and can provide the
information) is available from a ‘DocumentType’ object.  The
‘DocumentType’ for a document is available from the ‘Document’ object’s
‘doctype’ attribute; if there is no ‘DOCTYPE’ declaration for the
document, the document’s ‘doctype’ attribute will be set to ‘None’
instead of an instance of this interface.

‘DocumentType’ is a specialization of ‘Node’, and adds the following
attributes:

 -- Attribute: DocumentType.publicId

     The public identifier for the external subset of the document type
     definition.  This will be a string or ‘None’.

 -- Attribute: DocumentType.systemId

     The system identifier for the external subset of the document type
     definition.  This will be a URI as a string, or ‘None’.

 -- Attribute: DocumentType.internalSubset

     A string giving the complete internal subset from the document.
     This does not include the brackets which enclose the subset.  If
     the document has no internal subset, this should be ‘None’.

 -- Attribute: DocumentType.name

     The name of the root element as given in the ‘DOCTYPE’ declaration,
     if present.

 -- Attribute: DocumentType.entities

     This is a ‘NamedNodeMap’ giving the definitions of external
     entities.  For entity names defined more than once, only the first
     definition is provided (others are ignored as required by the XML
     recommendation).  This may be ‘None’ if the information is not
     provided by the parser, or if no entities are defined.

 -- Attribute: DocumentType.notations

     This is a ‘NamedNodeMap’ giving the definitions of notations.  For
     notation names defined more than once, only the first definition is
     provided (others are ignored as required by the XML
     recommendation).  This may be ‘None’ if the information is not
     provided by the parser, or if no notations are defined.


File: python.info,  Node: Document Objects,  Next: Element Objects<2>,  Prev: DocumentType Objects,  Up: Objects in the DOM

5.21.6.7 Document Objects
.........................

A ‘Document’ represents an entire XML document, including its
constituent elements, attributes, processing instructions, comments etc.
Remember that it inherits properties from ‘Node’.

 -- Attribute: Document.documentElement

     The one and only root element of the document.

 -- Method: Document.createElement (tagName)

     Create and return a new element node.  The element is not inserted
     into the document when it is created.  You need to explicitly
     insert it with one of the other methods such as ‘insertBefore()’ or
     ‘appendChild()’.

 -- Method: Document.createElementNS (namespaceURI, tagName)

     Create and return a new element with a namespace.  The 'tagName'
     may have a prefix.  The element is not inserted into the document
     when it is created.  You need to explicitly insert it with one of
     the other methods such as ‘insertBefore()’ or ‘appendChild()’.

 -- Method: Document.createTextNode (data)

     Create and return a text node containing the data passed as a
     parameter.  As with the other creation methods, this one does not
     insert the node into the tree.

 -- Method: Document.createComment (data)

     Create and return a comment node containing the data passed as a
     parameter.  As with the other creation methods, this one does not
     insert the node into the tree.

 -- Method: Document.createProcessingInstruction (target, data)

     Create and return a processing instruction node containing the
     'target' and 'data' passed as parameters.  As with the other
     creation methods, this one does not insert the node into the tree.

 -- Method: Document.createAttribute (name)

     Create and return an attribute node.  This method does not
     associate the attribute node with any particular element.  You must
     use ‘setAttributeNode()’ on the appropriate ‘Element’ object to use
     the newly created attribute instance.

 -- Method: Document.createAttributeNS (namespaceURI, qualifiedName)

     Create and return an attribute node with a namespace.  The
     'tagName' may have a prefix.  This method does not associate the
     attribute node with any particular element.  You must use
     ‘setAttributeNode()’ on the appropriate ‘Element’ object to use the
     newly created attribute instance.

 -- Method: Document.getElementsByTagName (tagName)

     Search for all descendants (direct children, children’s children,
     etc.)  with a particular element type name.

 -- Method: Document.getElementsByTagNameNS (namespaceURI, localName)

     Search for all descendants (direct children, children’s children,
     etc.)  with a particular namespace URI and localname.  The
     localname is the part of the namespace after the prefix.


File: python.info,  Node: Element Objects<2>,  Next: Attr Objects,  Prev: Document Objects,  Up: Objects in the DOM

5.21.6.8 Element Objects
........................

‘Element’ is a subclass of ‘Node’, so inherits all the attributes of
that class.

 -- Attribute: Element.tagName

     The element type name.  In a namespace-using document it may have
     colons in it.  The value is a string.

 -- Method: Element.getElementsByTagName (tagName)

     Same as equivalent method in the ‘Document’ class.

 -- Method: Element.getElementsByTagNameNS (namespaceURI, localName)

     Same as equivalent method in the ‘Document’ class.

 -- Method: Element.hasAttribute (name)

     Return ‘True’ if the element has an attribute named by 'name'.

 -- Method: Element.hasAttributeNS (namespaceURI, localName)

     Return ‘True’ if the element has an attribute named by
     'namespaceURI' and 'localName'.

 -- Method: Element.getAttribute (name)

     Return the value of the attribute named by 'name' as a string.  If
     no such attribute exists, an empty string is returned, as if the
     attribute had no value.

 -- Method: Element.getAttributeNode (attrname)

     Return the ‘Attr’ node for the attribute named by 'attrname'.

 -- Method: Element.getAttributeNS (namespaceURI, localName)

     Return the value of the attribute named by 'namespaceURI' and
     'localName' as a string.  If no such attribute exists, an empty
     string is returned, as if the attribute had no value.

 -- Method: Element.getAttributeNodeNS (namespaceURI, localName)

     Return an attribute value as a node, given a 'namespaceURI' and
     'localName'.

 -- Method: Element.removeAttribute (name)

     Remove an attribute by name.  If there is no matching attribute, a
     *note NotFoundErr: 3a5d. is raised.

 -- Method: Element.removeAttributeNode (oldAttr)

     Remove and return 'oldAttr' from the attribute list, if present.
     If 'oldAttr' is not present, *note NotFoundErr: 3a5d. is raised.

 -- Method: Element.removeAttributeNS (namespaceURI, localName)

     Remove an attribute by name.  Note that it uses a localName, not a
     qname.  No exception is raised if there is no matching attribute.

 -- Method: Element.setAttribute (name, value)

     Set an attribute value from a string.

 -- Method: Element.setAttributeNode (newAttr)

     Add a new attribute node to the element, replacing an existing
     attribute if necessary if the ‘name’ attribute matches.  If a
     replacement occurs, the old attribute node will be returned.  If
     'newAttr' is already in use, *note InuseAttributeErr: 3a62. will be
     raised.

 -- Method: Element.setAttributeNodeNS (newAttr)

     Add a new attribute node to the element, replacing an existing
     attribute if necessary if the ‘namespaceURI’ and ‘localName’
     attributes match.  If a replacement occurs, the old attribute node
     will be returned.  If 'newAttr' is already in use, *note
     InuseAttributeErr: 3a62. will be raised.

 -- Method: Element.setAttributeNS (namespaceURI, qname, value)

     Set an attribute value from a string, given a 'namespaceURI' and a
     'qname'.  Note that a qname is the whole attribute name.  This is
     different than above.


File: python.info,  Node: Attr Objects,  Next: NamedNodeMap Objects,  Prev: Element Objects<2>,  Up: Objects in the DOM

5.21.6.9 Attr Objects
.....................

‘Attr’ inherits from ‘Node’, so inherits all its attributes.

 -- Attribute: Attr.name

     The attribute name.  In a namespace-using document it may include a
     colon.

 -- Attribute: Attr.localName

     The part of the name following the colon if there is one, else the
     entire name.  This is a read-only attribute.

 -- Attribute: Attr.prefix

     The part of the name preceding the colon if there is one, else the
     empty string.

 -- Attribute: Attr.value

     The text value of the attribute.  This is a synonym for the
     ‘nodeValue’ attribute.


File: python.info,  Node: NamedNodeMap Objects,  Next: Comment Objects,  Prev: Attr Objects,  Up: Objects in the DOM

5.21.6.10 NamedNodeMap Objects
..............................

‘NamedNodeMap’ does 'not' inherit from ‘Node’.

 -- Attribute: NamedNodeMap.length

     The length of the attribute list.

 -- Method: NamedNodeMap.item (index)

     Return an attribute with a particular index.  The order you get the
     attributes in is arbitrary but will be consistent for the life of a
     DOM. Each item is an attribute node.  Get its value with the
     ‘value’ attribute.

There are also experimental methods that give this class more mapping
behavior.  You can use them or you can use the standardized
‘getAttribute*()’ family of methods on the ‘Element’ objects.


File: python.info,  Node: Comment Objects,  Next: Text and CDATASection Objects,  Prev: NamedNodeMap Objects,  Up: Objects in the DOM

5.21.6.11 Comment Objects
.........................

‘Comment’ represents a comment in the XML document.  It is a subclass of
‘Node’, but cannot have child nodes.

 -- Attribute: Comment.data

     The content of the comment as a string.  The attribute contains all
     characters between the leading ‘<!-’‘-’ and trailing ‘-’‘->’, but
     does not include them.


File: python.info,  Node: Text and CDATASection Objects,  Next: ProcessingInstruction Objects,  Prev: Comment Objects,  Up: Objects in the DOM

5.21.6.12 Text and CDATASection Objects
.......................................

The ‘Text’ interface represents text in the XML document.  If the parser
and DOM implementation support the DOM’s XML extension, portions of the
text enclosed in CDATA marked sections are stored in ‘CDATASection’
objects.  These two interfaces are identical, but provide different
values for the ‘nodeType’ attribute.

These interfaces extend the ‘Node’ interface.  They cannot have child
nodes.

 -- Attribute: Text.data

     The content of the text node as a string.

     Note: The use of a ‘CDATASection’ node does not indicate that the
     node represents a complete CDATA marked section, only that the
     content of the node was part of a CDATA section.  A single CDATA
     section may be represented by more than one node in the document
     tree.  There is no way to determine whether two adjacent
     ‘CDATASection’ nodes represent different CDATA marked sections.


File: python.info,  Node: ProcessingInstruction Objects,  Next: Exceptions<20>,  Prev: Text and CDATASection Objects,  Up: Objects in the DOM

5.21.6.13 ProcessingInstruction Objects
.......................................

Represents a processing instruction in the XML document; this inherits
from the ‘Node’ interface and cannot have child nodes.

 -- Attribute: ProcessingInstruction.target

     The content of the processing instruction up to the first
     whitespace character.  This is a read-only attribute.

 -- Attribute: ProcessingInstruction.data

     The content of the processing instruction following the first
     whitespace character.


File: python.info,  Node: Exceptions<20>,  Prev: ProcessingInstruction Objects,  Up: Objects in the DOM

5.21.6.14 Exceptions
....................

The DOM Level 2 recommendation defines a single exception, *note
DOMException: 3a77, and a number of constants that allow applications to
determine what sort of error occurred.  ‘DOMException’ instances carry a
*note code: 1a. attribute that provides the appropriate value for the
specific exception.

The Python DOM interface provides the constants, but also expands the
set of exceptions so that a specific exception exists for each of the
exception codes defined by the DOM. The implementations must raise the
appropriate specific exception, each of which carries the appropriate
value for the *note code: 1a. attribute.

 -- Exception: xml.dom.DOMException

     Base exception class used for all specific DOM exceptions.  This
     exception class cannot be directly instantiated.

 -- Exception: xml.dom.DomstringSizeErr

     Raised when a specified range of text does not fit into a string.
     This is not known to be used in the Python DOM implementations, but
     may be received from DOM implementations not written in Python.

 -- Exception: xml.dom.HierarchyRequestErr

     Raised when an attempt is made to insert a node where the node type
     is not allowed.

 -- Exception: xml.dom.IndexSizeErr

     Raised when an index or size parameter to a method is negative or
     exceeds the allowed values.

 -- Exception: xml.dom.InuseAttributeErr

     Raised when an attempt is made to insert an ‘Attr’ node that is
     already present elsewhere in the document.

 -- Exception: xml.dom.InvalidAccessErr

     Raised if a parameter or an operation is not supported on the
     underlying object.

 -- Exception: xml.dom.InvalidCharacterErr

     This exception is raised when a string parameter contains a
     character that is not permitted in the context it’s being used in
     by the XML 1.0 recommendation.  For example, attempting to create
     an ‘Element’ node with a space in the element type name will cause
     this error to be raised.

 -- Exception: xml.dom.InvalidModificationErr

     Raised when an attempt is made to modify the type of a node.

 -- Exception: xml.dom.InvalidStateErr

     Raised when an attempt is made to use an object that is not defined
     or is no longer usable.

 -- Exception: xml.dom.NamespaceErr

     If an attempt is made to change any object in a way that is not
     permitted with regard to the Namespaces in XML(1) recommendation,
     this exception is raised.

 -- Exception: xml.dom.NotFoundErr

     Exception when a node does not exist in the referenced context.
     For example, ‘NamedNodeMap.removeNamedItem()’ will raise this if
     the node passed in does not exist in the map.

 -- Exception: xml.dom.NotSupportedErr

     Raised when the implementation does not support the requested type
     of object or operation.

 -- Exception: xml.dom.NoDataAllowedErr

     This is raised if data is specified for a node which does not
     support data.

 -- Exception: xml.dom.NoModificationAllowedErr

     Raised on attempts to modify an object where modifications are not
     allowed (such as for read-only nodes).

 -- Exception: xml.dom.SyntaxErr

     Raised when an invalid or illegal string is specified.

 -- Exception: xml.dom.WrongDocumentErr

     Raised when a node is inserted in a different document than it
     currently belongs to, and the implementation does not support
     migrating the node from one document to the other.

The exception codes defined in the DOM recommendation map to the
exceptions described above according to this table:

Constant                                   Exception
                                           
---------------------------------------------------------------------------------
                                           
‘DOMSTRING_SIZE_ERR’                       *note DomstringSizeErr: 3a78.
                                           
                                           
‘HIERARCHY_REQUEST_ERR’                    *note HierarchyRequestErr: 3a79.
                                           
                                           
‘INDEX_SIZE_ERR’                           *note IndexSizeErr: 3a7a.
                                           
                                           
‘INUSE_ATTRIBUTE_ERR’                      *note InuseAttributeErr: 3a62.
                                           
                                           
‘INVALID_ACCESS_ERR’                       *note InvalidAccessErr: 3a7b.
                                           
                                           
‘INVALID_CHARACTER_ERR’                    *note InvalidCharacterErr: 3a7c.
                                           
                                           
‘INVALID_MODIFICATION_ERR’                 *note InvalidModificationErr: 3a7d.
                                           
                                           
‘INVALID_STATE_ERR’                        *note InvalidStateErr: 3a7e.
                                           
                                           
‘NAMESPACE_ERR’                            *note NamespaceErr: 3a7f.
                                           
                                           
‘NOT_FOUND_ERR’                            *note NotFoundErr: 3a5d.
                                           
                                           
‘NOT_SUPPORTED_ERR’                        *note NotSupportedErr: 3a80.
                                           
                                           
‘NO_DATA_ALLOWED_ERR’                      *note NoDataAllowedErr: 3a81.
                                           
                                           
‘NO_MODIFICATION_ALLOWED_ERR’              *note NoModificationAllowedErr: 3a82.
                                           
                                           
‘SYNTAX_ERR’                               *note SyntaxErr: 3a83.
                                           
                                           
‘WRONG_DOCUMENT_ERR’                       *note WrongDocumentErr: 3a84.
                                           

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/REC-xml-names/


File: python.info,  Node: Conformance,  Prev: Objects in the DOM,  Up: xml dom — The Document Object Model API

5.21.6.15 Conformance
.....................

This section describes the conformance requirements and relationships
between the Python DOM API, the W3C DOM recommendations, and the OMG IDL
mapping for Python.

* Menu:

* Type Mapping::
* Accessor Methods::


File: python.info,  Node: Type Mapping,  Next: Accessor Methods,  Up: Conformance

5.21.6.16 Type Mapping
......................

The IDL types used in the DOM specification are mapped to Python types
according to the following table.

IDL Type               Python Type
                       
-----------------------------------------------------------------------
                       
‘boolean’              ‘bool’ or ‘int’
                       
                       
‘int’                  ‘int’
                       
                       
‘long int’             ‘int’
                       
                       
‘unsigned int’         ‘int’
                       
                       
‘DOMString’            ‘str’ or ‘bytes’
                       
                       
‘null’                 ‘None’
                       


File: python.info,  Node: Accessor Methods,  Prev: Type Mapping,  Up: Conformance

5.21.6.17 Accessor Methods
..........................

The mapping from OMG IDL to Python defines accessor functions for IDL
‘attribute’ declarations in much the way the Java mapping does.  Mapping
the IDL declarations

     readonly attribute string someValue;
              attribute string anotherValue;

yields three accessor functions: a “get” method for ‘someValue’
(‘_get_someValue()’), and “get” and “set” methods for ‘anotherValue’
(‘_get_anotherValue()’ and ‘_set_anotherValue()’).  The mapping, in
particular, does not require that the IDL attributes are accessible as
normal Python attributes: ‘object.someValue’ is 'not' required to work,
and may raise an *note AttributeError: 34e.

The Python DOM API, however, 'does' require that normal attribute access
work.  This means that the typical surrogates generated by Python IDL
compilers are not likely to work, and wrapper objects may be needed on
the client if the DOM objects are accessed via CORBA. While this does
require some additional consideration for CORBA DOM clients, the
implementers with experience using DOM over CORBA from Python do not
consider this a problem.  Attributes that are declared ‘readonly’ may
not restrict write access in all DOM implementations.

In the Python DOM API, accessor functions are not required.  If
provided, they should take the form defined by the Python IDL mapping,
but these methods are considered unnecessary since the attributes are
accessible directly from Python.  “Set” accessors should never be
provided for ‘readonly’ attributes.

The IDL definitions do not fully embody the requirements of the W3C DOM
API, such as the notion of certain objects, such as the return value of
‘getElementsByTagName()’, being “live”.  The Python DOM API does not
require implementations to enforce such requirements.


File: python.info,  Node: xml dom minidom — Minimal DOM implementation,  Next: xml dom pulldom — Support for building partial DOM trees,  Prev: xml dom — The Document Object Model API,  Up: Structured Markup Processing Tools

5.21.7 ‘xml.dom.minidom’ — Minimal DOM implementation
-----------------------------------------------------

'Source code:' Lib/xml/dom/minidom.py(1)

__________________________________________________________________

‘xml.dom.minidom’ is a minimal implementation of the Document Object
Model interface, with an API similar to that in other languages.  It is
intended to be simpler than the full DOM and also significantly smaller.
Users who are not already proficient with the DOM should consider using
the *note xml.etree.ElementTree: 125. module for their XML processing
instead.

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

DOM applications typically start by parsing some XML into a DOM. With
‘xml.dom.minidom’, this is done through the parse functions:

     from xml.dom.minidom import parse, parseString

     dom1 = parse('c:\\temp\\mydata.xml')  # parse an XML file by name

     datasource = open('c:\\temp\\mydata.xml')
     dom2 = parse(datasource)  # parse an open file

     dom3 = parseString('<myxml>Some data<empty/> some more data</myxml>')

The *note parse(): 3a8d. function can take either a filename or an open
file object.

 -- Function: xml.dom.minidom.parse (filename_or_file, parser=None,
          bufsize=None)

     Return a ‘Document’ from the given input.  'filename_or_file' may
     be either a file name, or a file-like object.  'parser', if given,
     must be a SAX2 parser object.  This function will change the
     document handler of the parser and activate namespace support;
     other parser configuration (like setting an entity resolver) must
     have been done in advance.

If you have XML in a string, you can use the *note parseString(): 3a8e.
function instead:

 -- Function: xml.dom.minidom.parseString (string, parser=None)

     Return a ‘Document’ that represents the 'string'.  This method
     creates an *note io.StringIO: f5e. object for the string and passes
     that on to *note parse(): 3a8d.

Both functions return a ‘Document’ object representing the content of
the document.

What the *note parse(): 3a8d. and *note parseString(): 3a8e. functions
do is connect an XML parser with a “DOM builder” that can accept parse
events from any SAX parser and convert them into a DOM tree.  The names
of the functions are perhaps misleading, but are easy to grasp when
learning the interfaces.  The parsing of the document will be completed
before these functions return; it’s simply that these functions do not
provide a parser implementation themselves.

You can also create a ‘Document’ by calling a method on a “DOM
Implementation” object.  You can get this object either by calling the
‘getDOMImplementation()’ function in the *note xml.dom: 121. package or
the ‘xml.dom.minidom’ module.  Once you have a ‘Document’, you can add
child nodes to it to populate the DOM:

     from xml.dom.minidom import getDOMImplementation

     impl = getDOMImplementation()

     newdoc = impl.createDocument(None, "some_tag", None)
     top_element = newdoc.documentElement
     text = newdoc.createTextNode('Some textual content.')
     top_element.appendChild(text)

Once you have a DOM document object, you can access the parts of your
XML document through its properties and methods.  These properties are
defined in the DOM specification.  The main property of the document
object is the ‘documentElement’ property.  It gives you the main element
in the XML document: the one that holds all others.  Here is an example
program:

     dom3 = parseString("<myxml>Some data</myxml>")
     assert dom3.documentElement.tagName == "myxml"

When you are finished with a DOM tree, you may optionally call the
‘unlink()’ method to encourage early cleanup of the now-unneeded
objects.  ‘unlink()’ is an ‘xml.dom.minidom’-specific extension to the
DOM API that renders the node and its descendants essentially useless.
Otherwise, Python’s garbage collector will eventually take care of the
objects in the tree.

See also
........

Document Object Model (DOM) Level 1 Specification(2)

     The W3C recommendation for the DOM supported by ‘xml.dom.minidom’.

* Menu:

* DOM Objects::
* DOM Example::
* minidom and the DOM standard::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/dom/minidom.py

   (2) https://www.w3.org/TR/REC-DOM-Level-1/


File: python.info,  Node: DOM Objects,  Next: DOM Example,  Up: xml dom minidom — Minimal DOM implementation

5.21.7.1 DOM Objects
....................

The definition of the DOM API for Python is given as part of the *note
xml.dom: 121. module documentation.  This section lists the differences
between the API and ‘xml.dom.minidom’.

 -- Method: Node.unlink ()

     Break internal references within the DOM so that it will be garbage
     collected on versions of Python without cyclic GC. Even when cyclic
     GC is available, using this can make large amounts of memory
     available sooner, so calling this on DOM objects as soon as they
     are no longer needed is good practice.  This only needs to be
     called on the ‘Document’ object, but may be called on child nodes
     to discard children of that node.

     You can avoid calling this method explicitly by using the *note
     with: 5d5. statement.  The following code will automatically unlink
     'dom' when the ‘with’ block is exited:

          with xml.dom.minidom.parse(datasource) as dom:
              ... # Work with dom.

 -- Method: Node.writexml (writer, indent='', addindent='', newl='',
          encoding=None, standalone=None)

     Write XML to the writer object.  The writer receives texts but not
     bytes as input, it should have a ‘write()’ method which matches
     that of the file object interface.  The 'indent' parameter is the
     indentation of the current node.  The 'addindent' parameter is the
     incremental indentation to use for subnodes of the current one.
     The 'newl' parameter specifies the string to use to terminate
     newlines.

     For the ‘Document’ node, an additional keyword argument 'encoding'
     can be used to specify the encoding field of the XML header.

     Similarly, explicitly stating the 'standalone' argument causes the
     standalone document declarations to be added to the prologue of the
     XML document.  If the value is set to ‘True’, ‘standalone="yes"’ is
     added, otherwise it is set to ‘"no"’.  Not stating the argument
     will omit the declaration from the document.

     Changed in version 3.8: The ‘writexml()’ method now preserves the
     attribute order specified by the user.

     Changed in version 3.9: The 'standalone' parameter was added.

 -- Method: Node.toxml (encoding=None, standalone=None)

     Return a string or byte string containing the XML represented by
     the DOM node.

     With an explicit 'encoding' (1) argument, the result is a byte
     string in the specified encoding.  With no 'encoding' argument, the
     result is a Unicode string, and the XML declaration in the
     resulting string does not specify an encoding.  Encoding this
     string in an encoding other than UTF-8 is likely incorrect, since
     UTF-8 is the default encoding of XML.

     The 'standalone' argument behaves exactly as in *note writexml():
     aa7.

     Changed in version 3.8: The ‘toxml()’ method now preserves the
     attribute order specified by the user.

     Changed in version 3.9: The 'standalone' parameter was added.

 -- Method: Node.toprettyxml (indent='\t', newl='\n', encoding=None,
          standalone=None)

     Return a pretty-printed version of the document.  'indent'
     specifies the indentation string and defaults to a tabulator;
     'newl' specifies the string emitted at the end of each line and
     defaults to ‘\n’.

     The 'encoding' argument behaves like the corresponding argument of
     *note toxml(): aa8.

     The 'standalone' argument behaves exactly as in *note writexml():
     aa7.

     Changed in version 3.8: The ‘toprettyxml()’ method now preserves
     the attribute order specified by the user.

     Changed in version 3.9: The 'standalone' parameter was added.

   ---------- Footnotes ----------

   (1) The encoding name included in the XML output should conform to
the appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not valid in an XML document’s declaration, even though Python accepts
it as an encoding name.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.


File: python.info,  Node: DOM Example,  Next: minidom and the DOM standard,  Prev: DOM Objects,  Up: xml dom minidom — Minimal DOM implementation

5.21.7.2 DOM Example
....................

This example program is a fairly realistic example of a simple program.
In this particular case, we do not take much advantage of the
flexibility of the DOM.

     import xml.dom.minidom

     document = """\
     <slideshow>
     <title>Demo slideshow</title>
     <slide><title>Slide title</title>
     <point>This is a demo</point>
     <point>Of a program for processing slides</point>
     </slide>

     <slide><title>Another demo slide</title>
     <point>It is important</point>
     <point>To have more than</point>
     <point>one slide</point>
     </slide>
     </slideshow>
     """

     dom = xml.dom.minidom.parseString(document)

     def getText(nodelist):
         rc = []
         for node in nodelist:
             if node.nodeType == node.TEXT_NODE:
                 rc.append(node.data)
         return ''.join(rc)

     def handleSlideshow(slideshow):
         print("<html>")
         handleSlideshowTitle(slideshow.getElementsByTagName("title")[0])
         slides = slideshow.getElementsByTagName("slide")
         handleToc(slides)
         handleSlides(slides)
         print("</html>")

     def handleSlides(slides):
         for slide in slides:
             handleSlide(slide)

     def handleSlide(slide):
         handleSlideTitle(slide.getElementsByTagName("title")[0])
         handlePoints(slide.getElementsByTagName("point"))

     def handleSlideshowTitle(title):
         print(f"<title>{getText(title.childNodes)}</title>")

     def handleSlideTitle(title):
         print(f"<h2>{getText(title.childNodes)}</h2>")

     def handlePoints(points):
         print("<ul>")
         for point in points:
             handlePoint(point)
         print("</ul>")

     def handlePoint(point):
         print(f"<li>{getText(point.childNodes)}</li>")

     def handleToc(slides):
         for slide in slides:
             title = slide.getElementsByTagName("title")[0]
             print(f"<p>{getText(title.childNodes)}</p>")

     handleSlideshow(dom)


File: python.info,  Node: minidom and the DOM standard,  Prev: DOM Example,  Up: xml dom minidom — Minimal DOM implementation

5.21.7.3 minidom and the DOM standard
.....................................

The ‘xml.dom.minidom’ module is essentially a DOM 1.0-compatible DOM
with some DOM 2 features (primarily namespace features).

Usage of the DOM interface in Python is straight-forward.  The following
mapping rules apply:

   * Interfaces are accessed through instance objects.  Applications
     should not instantiate the classes themselves; they should use the
     creator functions available on the ‘Document’ object.  Derived
     interfaces support all operations (and attributes) from the base
     interfaces, plus any new operations.

   * Operations are used as methods.  Since the DOM uses only *note in:
     2f4. parameters, the arguments are passed in normal order (from
     left to right).  There are no optional arguments.  ‘void’
     operations return ‘None’.

   * IDL attributes map to instance attributes.  For compatibility with
     the OMG IDL language mapping for Python, an attribute ‘foo’ can
     also be accessed through accessor methods ‘_get_foo()’ and
     ‘_set_foo()’.  ‘readonly’ attributes must not be changed; this is
     not enforced at runtime.

   * The types ‘short int’, ‘unsigned int’, ‘unsigned long long’, and
     ‘boolean’ all map to Python integer objects.

   * The type ‘DOMString’ maps to Python strings.  ‘xml.dom.minidom’
     supports either bytes or strings, but will normally produce
     strings.  Values of type ‘DOMString’ may also be ‘None’ where
     allowed to have the IDL ‘null’ value by the DOM specification from
     the W3C.

   * ‘const’ declarations map to variables in their respective scope
     (e.g.  ‘xml.dom.minidom.Node.PROCESSING_INSTRUCTION_NODE’); they
     must not be changed.

   * ‘DOMException’ is currently not supported in ‘xml.dom.minidom’.
     Instead, ‘xml.dom.minidom’ uses standard Python exceptions such as
     *note TypeError: 2c3. and *note AttributeError: 34e.

   * ‘NodeList’ objects are implemented using Python’s built-in list
     type.  These objects provide the interface defined in the DOM
     specification, but with earlier versions of Python they do not
     support the official API. They are, however, much more “Pythonic”
     than the interface defined in the W3C recommendations.

The following interfaces have no implementation in ‘xml.dom.minidom’:

   * ‘DOMTimeStamp’

   * ‘EntityReference’

Most of these reflect information in the XML document that is not of
general utility to most DOM users.


File: python.info,  Node: xml dom pulldom — Support for building partial DOM trees,  Next: xml sax — Support for SAX2 parsers,  Prev: xml dom minidom — Minimal DOM implementation,  Up: Structured Markup Processing Tools

5.21.8 ‘xml.dom.pulldom’ — Support for building partial DOM trees
-----------------------------------------------------------------

'Source code:' Lib/xml/dom/pulldom.py(1)

__________________________________________________________________

The ‘xml.dom.pulldom’ module provides a “pull parser” which can also be
asked to produce DOM-accessible fragments of the document where
necessary.  The basic concept involves pulling “events” from a stream of
incoming XML and processing them.  In contrast to SAX which also employs
an event-driven processing model together with callbacks, the user of a
pull parser is responsible for explicitly pulling events from the
stream, looping over those events until either processing is finished or
an error condition occurs.

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

Changed in version 3.7.1: The SAX parser no longer processes general
external entities by default to increase security by default.  To enable
processing of external entities, pass a custom parser instance in:

     from xml.dom.pulldom import parse
     from xml.sax import make_parser
     from xml.sax.handler import feature_external_ges

     parser = make_parser()
     parser.setFeature(feature_external_ges, True)
     parse(filename, parser=parser)

Example:

     from xml.dom import pulldom

     doc = pulldom.parse('sales_items.xml')
     for event, node in doc:
         if event == pulldom.START_ELEMENT and node.tagName == 'item':
             if int(node.getAttribute('price')) > 50:
                 doc.expandNode(node)
                 print(node.toxml())

‘event’ is a constant and can be one of:

   * ‘START_ELEMENT’

   * ‘END_ELEMENT’

   * ‘COMMENT’

   * ‘START_DOCUMENT’

   * ‘END_DOCUMENT’

   * ‘CHARACTERS’

   * ‘PROCESSING_INSTRUCTION’

   * ‘IGNORABLE_WHITESPACE’

‘node’ is an object of type ‘xml.dom.minidom.Document’,
‘xml.dom.minidom.Element’ or ‘xml.dom.minidom.Text’.

Since the document is treated as a “flat” stream of events, the document
“tree” is implicitly traversed and the desired elements are found
regardless of their depth in the tree.  In other words, one does not
need to consider hierarchical issues such as recursive searching of the
document nodes, although if the context of elements were important, one
would either need to maintain some context-related state (i.e.
remembering where one is in the document at any given point) or to make
use of the *note DOMEventStream.expandNode(): 3a99. method and switch to
DOM-related processing.

 -- Class: xml.dom.pulldom.PullDOM (documentFactory=None)

     Subclass of *note xml.sax.handler.ContentHandler: 3a9b.

 -- Class: xml.dom.pulldom.SAX2DOM (documentFactory=None)

     Subclass of *note xml.sax.handler.ContentHandler: 3a9b.

 -- Function: xml.dom.pulldom.parse (stream_or_string, parser=None,
          bufsize=None)

     Return a *note DOMEventStream: 738. from the given input.
     'stream_or_string' may be either a file name, or a file-like
     object.  'parser', if given, must be an *note XMLReader: 3a9e.
     object.  This function will change the document handler of the
     parser and activate namespace support; other parser configuration
     (like setting an entity resolver) must have been done in advance.

If you have XML in a string, you can use the *note parseString(): 3a9f.
function instead:

 -- Function: xml.dom.pulldom.parseString (string, parser=None)

     Return a *note DOMEventStream: 738. that represents the (Unicode)
     'string'.

 -- Data: xml.dom.pulldom.default_bufsize

     Default value for the 'bufsize' parameter to *note parse(): 3a9d.

     The value of this variable can be changed before calling *note
     parse(): 3a9d. and the new value will take effect.

* Menu:

* DOMEventStream Objects::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/dom/pulldom.py


File: python.info,  Node: DOMEventStream Objects,  Up: xml dom pulldom — Support for building partial DOM trees

5.21.8.1 DOMEventStream Objects
...............................

 -- Class: xml.dom.pulldom.DOMEventStream (stream, parser, bufsize)

     Changed in version 3.11: Support for *note __getitem__(): 283.
     method has been removed.

      -- Method: getEvent ()

          Return a tuple containing 'event' and the current 'node' as
          ‘xml.dom.minidom.Document’ if event equals ‘START_DOCUMENT’,
          ‘xml.dom.minidom.Element’ if event equals ‘START_ELEMENT’ or
          ‘END_ELEMENT’ or ‘xml.dom.minidom.Text’ if event equals
          ‘CHARACTERS’.  The current node does not contain information
          about its children, unless *note expandNode(): 3a99. is
          called.

      -- Method: expandNode (node)

          Expands all children of 'node' into 'node'.  Example:

               from xml.dom import pulldom

               xml = '<html><title>Foo</title> <p>Some text <div>and more</div></p> </html>'
               doc = pulldom.parseString(xml)
               for event, node in doc:
                   if event == pulldom.START_ELEMENT and node.tagName == 'p':
                       # Following statement only prints '<p/>'
                       print(node.toxml())
                       doc.expandNode(node)
                       # Following statement prints node with all its children '<p>Some text <div>and more</div></p>'
                       print(node.toxml())

      -- Method: reset ()


File: python.info,  Node: xml sax — Support for SAX2 parsers,  Next: xml sax handler — Base classes for SAX handlers,  Prev: xml dom pulldom — Support for building partial DOM trees,  Up: Structured Markup Processing Tools

5.21.9 ‘xml.sax’ — Support for SAX2 parsers
-------------------------------------------

'Source code:' Lib/xml/sax/__init__.py(1)

__________________________________________________________________

The ‘xml.sax’ package provides a number of modules which implement the
Simple API for XML (SAX) interface for Python.  The package itself
provides the SAX exceptions and the convenience functions which will be
most used by users of the SAX API.

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

Changed in version 3.7.1: The SAX parser no longer processes general
external entities by default to increase security.  Before, the parser
created network connections to fetch remote files or loaded local files
from the file system for DTD and entities.  The feature can be enabled
again with method *note setFeature(): 3aa8. on the parser object and
argument *note feature_external_ges: 1604.

The convenience functions are:

 -- Function: xml.sax.make_parser (parser_list=[])

     Create and return a SAX *note XMLReader: 3a9e. object.  The first
     parser found will be used.  If 'parser_list' is provided, it must
     be an iterable of strings which name modules that have a function
     named ‘create_parser()’.  Modules listed in 'parser_list' will be
     used before modules in the default list of parsers.

     Changed in version 3.8: The 'parser_list' argument can be any
     iterable, not just a list.

 -- Function: xml.sax.parse (filename_or_stream, handler,
          error_handler=handler.ErrorHandler())

     Create a SAX parser and use it to parse a document.  The document,
     passed in as 'filename_or_stream', can be a filename or a file
     object.  The 'handler' parameter needs to be a SAX *note
     ContentHandler: 3a9b. instance.  If 'error_handler' is given, it
     must be a SAX *note ErrorHandler: 3aa9. instance; if omitted, *note
     SAXParseException: 3aaa. will be raised on all errors.  There is no
     return value; all work must be done by the 'handler' passed in.

 -- Function: xml.sax.parseString (string, handler,
          error_handler=handler.ErrorHandler())

     Similar to *note parse(): 1b94, but parses from a buffer 'string'
     received as a parameter.  'string' must be a *note str: 44f.
     instance or a *note bytes-like object: d55.

     Changed in version 3.5: Added support of *note str: 44f. instances.

A typical SAX application uses three kinds of objects: readers, handlers
and input sources.  “Reader” in this context is another term for parser,
i.e.  some piece of code that reads the bytes or characters from the
input source, and produces a sequence of events.  The events then get
distributed to the handler objects, i.e.  the reader invokes a method on
the handler.  A SAX application must therefore obtain a reader object,
create or open the input sources, create the handlers, and connect these
objects all together.  As the final step of preparation, the reader is
called to parse the input.  During parsing, methods on the handler
objects are called based on structural and syntactic events from the
input data.

For these objects, only the interfaces are relevant; they are normally
not instantiated by the application itself.  Since Python does not have
an explicit notion of interface, they are formally introduced as
classes, but applications may use implementations which do not inherit
from the provided classes.  The *note InputSource: ecf, *note Locator:
3aab, ‘Attributes’, ‘AttributesNS’, and *note XMLReader: 3a9e.
interfaces are defined in the module *note xml.sax.xmlreader: 12c.  The
handler interfaces are defined in *note xml.sax.handler: 12a.  For
convenience, ‘InputSource’ (which is often instantiated directly) and
the handler classes are also available from ‘xml.sax’.  These interfaces
are described below.

In addition to these classes, ‘xml.sax’ provides the following exception
classes.

 -- Exception: xml.sax.SAXException (msg, exception=None)

     Encapsulate an XML error or warning.  This class can contain basic
     error or warning information from either the XML parser or the
     application: it can be subclassed to provide additional
     functionality or to add localization.  Note that although the
     handlers defined in the *note ErrorHandler: 3aa9. interface receive
     instances of this exception, it is not required to actually raise
     the exception — it is also useful as a container for information.

     When instantiated, 'msg' should be a human-readable description of
     the error.  The optional 'exception' parameter, if given, should be
     ‘None’ or an exception that was caught by the parsing code and is
     being passed along as information.

     This is the base class for the other SAX exception classes.

 -- Exception: xml.sax.SAXParseException (msg, exception, locator)

     Subclass of *note SAXException: 3aac. raised on parse errors.
     Instances of this class are passed to the methods of the SAX *note
     ErrorHandler: 3aa9. interface to provide information about the
     parse error.  This class supports the SAX *note Locator: 3aab.
     interface as well as the *note SAXException: 3aac. interface.

 -- Exception: xml.sax.SAXNotRecognizedException (msg, exception=None)

     Subclass of *note SAXException: 3aac. raised when a SAX *note
     XMLReader: 3a9e. is confronted with an unrecognized feature or
     property.  SAX applications and extensions may use this class for
     similar purposes.

 -- Exception: xml.sax.SAXNotSupportedException (msg, exception=None)

     Subclass of *note SAXException: 3aac. raised when a SAX *note
     XMLReader: 3a9e. is asked to enable a feature that is not
     supported, or to set a property to a value that the implementation
     does not support.  SAX applications and extensions may use this
     class for similar purposes.

See also
........

SAX: The Simple API for XML(2)

     This site is the focal point for the definition of the SAX API. It
     provides a Java implementation and online documentation.  Links to
     implementations and historical information are also available.

Module *note xml.sax.handler: 12a.

     Definitions of the interfaces for application-provided objects.

Module *note xml.sax.saxutils: 12b.

     Convenience functions for use in SAX applications.

Module *note xml.sax.xmlreader: 12c.

     Definitions of the interfaces for parser-provided objects.

* Menu:

* SAXException Objects::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/sax/__init__.py

   (2) http://www.saxproject.org/


File: python.info,  Node: SAXException Objects,  Up: xml sax — Support for SAX2 parsers

5.21.9.1 SAXException Objects
.............................

The *note SAXException: 3aac. exception class supports the following
methods:

 -- Method: SAXException.getMessage ()

     Return a human-readable message describing the error condition.

 -- Method: SAXException.getException ()

     Return an encapsulated exception object, or ‘None’.


File: python.info,  Node: xml sax handler — Base classes for SAX handlers,  Next: xml sax saxutils — SAX Utilities,  Prev: xml sax — Support for SAX2 parsers,  Up: Structured Markup Processing Tools

5.21.10 ‘xml.sax.handler’ — Base classes for SAX handlers
---------------------------------------------------------

'Source code:' Lib/xml/sax/handler.py(1)

__________________________________________________________________

The SAX API defines five kinds of handlers: content handlers, DTD
handlers, error handlers, entity resolvers and lexical handlers.
Applications normally only need to implement those interfaces whose
events they are interested in; they can implement the interfaces in a
single object or in multiple objects.  Handler implementations should
inherit from the base classes provided in the module ‘xml.sax.handler’,
so that all methods get default implementations.

 -- Class: xml.sax.handler.ContentHandler

     This is the main callback interface in SAX, and the one most
     important to applications.  The order of events in this interface
     mirrors the order of the information in the document.

 -- Class: xml.sax.handler.DTDHandler

     Handle DTD events.

     This interface specifies only those DTD events required for basic
     parsing (unparsed entities and attributes).

 -- Class: xml.sax.handler.EntityResolver

     Basic interface for resolving entities.  If you create an object
     implementing this interface, then register the object with your
     Parser, the parser will call the method in your object to resolve
     all external entities.

 -- Class: xml.sax.handler.ErrorHandler

     Interface used by the parser to present error and warning messages
     to the application.  The methods of this object control whether
     errors are immediately converted to exceptions or are handled in
     some other way.

 -- Class: xml.sax.handler.LexicalHandler

     Interface used by the parser to represent low frequency events
     which may not be of interest to many applications.

In addition to these classes, ‘xml.sax.handler’ provides symbolic
constants for the feature and property names.

 -- Data: xml.sax.handler.feature_namespaces

          value: ‘"http://xml.org/sax/features/namespaces"’
          true: Perform Namespace processing.
          false: Optionally do not perform Namespace processing (implies namespace-prefixes; default).
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.feature_namespace_prefixes

          value: ‘"http://xml.org/sax/features/namespace-prefixes"’
          true: Report the original prefixed names and attributes used for Namespace declarations.
          false: Do not report attributes used for Namespace declarations, and optionally do not report original prefixed names (default).
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.feature_string_interning

          value: ‘"http://xml.org/sax/features/string-interning"’
          true: All element names, prefixes, attribute names, Namespace URIs, and local names are interned using the built-in intern function.
          false: Names are not necessarily interned, although they may be (default).
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.feature_validation

          value: ‘"http://xml.org/sax/features/validation"’
          true: Report all validation errors (implies external-general-entities and external-parameter-entities).
          false: Do not report validation errors.
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.feature_external_ges

          Warning: Enabling opens a vulnerability to external entity
          attacks(2) if the parser is used with user-provided XML
          content.  Please reflect on your threat model(3) before
          enabling this feature.

          value: ‘"http://xml.org/sax/features/external-general-entities"’
          true: Include all external general (text) entities.
          false: Do not include external general entities.
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.feature_external_pes

          value: ‘"http://xml.org/sax/features/external-parameter-entities"’
          true: Include all external parameter entities, including the external DTD subset.
          false: Do not include any external parameter entities, even the external DTD subset.
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.all_features

     List of all features.

 -- Data: xml.sax.handler.property_lexical_handler

          value: ‘"http://xml.org/sax/properties/lexical-handler"’
          data type: xml.sax.handler.LexicalHandler (not supported in Python 2)
          description: An optional extension handler for lexical events like comments.
          access: read/write

 -- Data: xml.sax.handler.property_declaration_handler

          value: ‘"http://xml.org/sax/properties/declaration-handler"’
          data type: xml.sax.sax2lib.DeclHandler (not supported in Python 2)
          description: An optional extension handler for DTD-related events other than notations and unparsed entities.
          access: read/write

 -- Data: xml.sax.handler.property_dom_node

          value: ‘"http://xml.org/sax/properties/dom-node"’
          data type: org.w3c.dom.Node (not supported in Python 2)
          description: When parsing, the current DOM node being visited if this is a DOM iterator; when not parsing, the root DOM node for iteration.
          access: (parsing) read-only; (not parsing) read/write

 -- Data: xml.sax.handler.property_xml_string

          value: ‘"http://xml.org/sax/properties/xml-string"’
          data type: Bytes
          description: The literal string of characters that was the source for the current event.
          access: read-only

 -- Data: xml.sax.handler.all_properties

     List of all known property names.

* Menu:

* ContentHandler Objects::
* DTDHandler Objects::
* EntityResolver Objects::
* ErrorHandler Objects::
* LexicalHandler Objects::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/sax/handler.py

   (2) https://en.wikipedia.org/wiki/XML_external_entity_attack

   (3) https://en.wikipedia.org/wiki/Threat_model


File: python.info,  Node: ContentHandler Objects,  Next: DTDHandler Objects,  Up: xml sax handler — Base classes for SAX handlers

5.21.10.1 ContentHandler Objects
................................

Users are expected to subclass *note ContentHandler: 3a9b. to support
their application.  The following methods are called by the parser on
the appropriate events in the input document:

 -- Method: ContentHandler.setDocumentLocator (locator)

     Called by the parser to give the application a locator for locating
     the origin of document events.

     SAX parsers are strongly encouraged (though not absolutely
     required) to supply a locator: if it does so, it must supply the
     locator to the application by invoking this method before invoking
     any of the other methods in the DocumentHandler interface.

     The locator allows the application to determine the end position of
     any document-related event, even if the parser is not reporting an
     error.  Typically, the application will use this information for
     reporting its own errors (such as character content that does not
     match an application’s business rules).  The information returned
     by the locator is probably not sufficient for use with a search
     engine.

     Note that the locator will return correct information only during
     the invocation of the events in this interface.  The application
     should not attempt to use it at any other time.

 -- Method: ContentHandler.startDocument ()

     Receive notification of the beginning of a document.

     The SAX parser will invoke this method only once, before any other
     methods in this interface or in DTDHandler (except for *note
     setDocumentLocator(): 3ac5.).

 -- Method: ContentHandler.endDocument ()

     Receive notification of the end of a document.

     The SAX parser will invoke this method only once, and it will be
     the last method invoked during the parse.  The parser shall not
     invoke this method until it has either abandoned parsing (because
     of an unrecoverable error) or reached the end of input.

 -- Method: ContentHandler.startPrefixMapping (prefix, uri)

     Begin the scope of a prefix-URI Namespace mapping.

     The information from this event is not necessary for normal
     Namespace processing: the SAX XML reader will automatically replace
     prefixes for element and attribute names when the
     ‘feature_namespaces’ feature is enabled (the default).

     There are cases, however, when applications need to use prefixes in
     character data or in attribute values, where they cannot safely be
     expanded automatically; the ‘startPrefixMapping()’ and *note
     endPrefixMapping(): 3ac9. events supply the information to the
     application to expand prefixes in those contexts itself, if
     necessary.

     Note that ‘startPrefixMapping()’ and *note endPrefixMapping():
     3ac9. events are not guaranteed to be properly nested relative to
     each-other: all ‘startPrefixMapping()’ events will occur before the
     corresponding *note startElement(): 1593. event, and all
     ‘endPrefixMapping()’ events will occur after the corresponding
     *note endElement(): 1594. event, but their order is not guaranteed.

 -- Method: ContentHandler.endPrefixMapping (prefix)

     End the scope of a prefix-URI mapping.

     See *note startPrefixMapping(): 3ac8. for details.  This event will
     always occur after the corresponding *note endElement(): 1594.
     event, but the order of ‘endPrefixMapping()’ events is not
     otherwise guaranteed.

 -- Method: ContentHandler.startElement (name, attrs)

     Signals the start of an element in non-namespace mode.

     The 'name' parameter contains the raw XML 1.0 name of the element
     type as a string and the 'attrs' parameter holds an object of the
     *note Attributes: 3aca. interface containing the attributes of the
     element.  The object passed as 'attrs' may be re-used by the
     parser; holding on to a reference to it is not a reliable way to
     keep a copy of the attributes.  To keep a copy of the attributes,
     use the *note copy(): 25. method of the 'attrs' object.

 -- Method: ContentHandler.endElement (name)

     Signals the end of an element in non-namespace mode.

     The 'name' parameter contains the name of the element type, just as
     with the *note startElement(): 1593. event.

 -- Method: ContentHandler.startElementNS (name, qname, attrs)

     Signals the start of an element in namespace mode.

     The 'name' parameter contains the name of the element type as a
     ‘(uri, localname)’ tuple, the 'qname' parameter contains the raw
     XML 1.0 name used in the source document, and the 'attrs' parameter
     holds an instance of the *note AttributesNS: 3acc. interface
     containing the attributes of the element.  If no namespace is
     associated with the element, the 'uri' component of 'name' will be
     ‘None’.  The object passed as 'attrs' may be re-used by the parser;
     holding on to a reference to it is not a reliable way to keep a
     copy of the attributes.  To keep a copy of the attributes, use the
     *note copy(): 25. method of the 'attrs' object.

     Parsers may set the 'qname' parameter to ‘None’, unless the
     ‘feature_namespace_prefixes’ feature is activated.

 -- Method: ContentHandler.endElementNS (name, qname)

     Signals the end of an element in namespace mode.

     The 'name' parameter contains the name of the element type, just as
     with the *note startElementNS(): 3acb. method, likewise the 'qname'
     parameter.

 -- Method: ContentHandler.characters (content)

     Receive notification of character data.

     The Parser will call this method to report each chunk of character
     data.  SAX parsers may return all contiguous character data in a
     single chunk, or they may split it into several chunks; however,
     all of the characters in any single event must come from the same
     external entity so that the Locator provides useful information.

     'content' may be a string or bytes instance; the ‘expat’ reader
     module always produces strings.

          Note: The earlier SAX 1 interface provided by the Python XML
          Special Interest Group used a more Java-like interface for
          this method.  Since most parsers used from Python did not take
          advantage of the older interface, the simpler signature was
          chosen to replace it.  To convert old code to the new
          interface, use 'content' instead of slicing content with the
          old 'offset' and 'length' parameters.

 -- Method: ContentHandler.ignorableWhitespace (whitespace)

     Receive notification of ignorable whitespace in element content.

     Validating Parsers must use this method to report each chunk of
     ignorable whitespace (see the W3C XML 1.0 recommendation, section
     2.10): non-validating parsers may also use this method if they are
     capable of parsing and using content models.

     SAX parsers may return all contiguous whitespace in a single chunk,
     or they may split it into several chunks; however, all of the
     characters in any single event must come from the same external
     entity, so that the Locator provides useful information.

 -- Method: ContentHandler.processingInstruction (target, data)

     Receive notification of a processing instruction.

     The Parser will invoke this method once for each processing
     instruction found: note that processing instructions may occur
     before or after the main document element.

     A SAX parser should never report an XML declaration (XML 1.0,
     section 2.8) or a text declaration (XML 1.0, section 4.3.1) using
     this method.

 -- Method: ContentHandler.skippedEntity (name)

     Receive notification of a skipped entity.

     The Parser will invoke this method once for each entity skipped.
     Non-validating processors may skip entities if they have not seen
     the declarations (because, for example, the entity was declared in
     an external DTD subset).  All processors may skip external
     entities, depending on the values of the ‘feature_external_ges’ and
     the ‘feature_external_pes’ properties.


File: python.info,  Node: DTDHandler Objects,  Next: EntityResolver Objects,  Prev: ContentHandler Objects,  Up: xml sax handler — Base classes for SAX handlers

5.21.10.2 DTDHandler Objects
............................

*note DTDHandler: 3ab6. instances provide the following methods:

 -- Method: DTDHandler.notationDecl (name, publicId, systemId)

     Handle a notation declaration event.

 -- Method: DTDHandler.unparsedEntityDecl (name, publicId, systemId,
          ndata)

     Handle an unparsed entity declaration event.


File: python.info,  Node: EntityResolver Objects,  Next: ErrorHandler Objects,  Prev: DTDHandler Objects,  Up: xml sax handler — Base classes for SAX handlers

5.21.10.3 EntityResolver Objects
................................

 -- Method: EntityResolver.resolveEntity (publicId, systemId)

     Resolve the system identifier of an entity and return either the
     system identifier to read from as a string, or an InputSource to
     read from.  The default implementation returns 'systemId'.


File: python.info,  Node: ErrorHandler Objects,  Next: LexicalHandler Objects,  Prev: EntityResolver Objects,  Up: xml sax handler — Base classes for SAX handlers

5.21.10.4 ErrorHandler Objects
..............................

Objects with this interface are used to receive error and warning
information from the *note XMLReader: 3a9e.  If you create an object
that implements this interface, then register the object with your
‘XMLReader’, the parser will call the methods in your object to report
all warnings and errors.  There are three levels of errors available:
warnings, (possibly) recoverable errors, and unrecoverable errors.  All
methods take a *note SAXParseException: 3aaa. as the only parameter.
Errors and warnings may be converted to an exception by raising the
passed-in exception object.

 -- Method: ErrorHandler.error (exception)

     Called when the parser encounters a recoverable error.  If this
     method does not raise an exception, parsing may continue, but
     further document information should not be expected by the
     application.  Allowing the parser to continue may allow additional
     errors to be discovered in the input document.

 -- Method: ErrorHandler.fatalError (exception)

     Called when the parser encounters an error it cannot recover from;
     parsing is expected to terminate when this method returns.

 -- Method: ErrorHandler.warning (exception)

     Called when the parser presents minor warning information to the
     application.  Parsing is expected to continue when this method
     returns, and document information will continue to be passed to the
     application.  Raising an exception in this method will cause
     parsing to end.


File: python.info,  Node: LexicalHandler Objects,  Prev: ErrorHandler Objects,  Up: xml sax handler — Base classes for SAX handlers

5.21.10.5 LexicalHandler Objects
................................

Optional SAX2 handler for lexical events.

This handler is used to obtain lexical information about an XML
document.  Lexical information includes information describing the
document encoding used and XML comments embedded in the document, as
well as section boundaries for the DTD and for any CDATA sections.  The
lexical handlers are used in the same manner as content handlers.

Set the LexicalHandler of an XMLReader by using the setProperty method
with the property identifier
‘'http://xml.org/sax/properties/lexical-handler'’.

 -- Method: LexicalHandler.comment (content)

     Reports a comment anywhere in the document (including the DTD and
     outside the document element).

 -- Method: LexicalHandler.startDTD (name, public_id, system_id)

     Reports the start of the DTD declarations if the document has an
     associated DTD.

 -- Method: LexicalHandler.endDTD ()

     Reports the end of DTD declaration.

 -- Method: LexicalHandler.startCDATA ()

     Reports the start of a CDATA marked section.

     The contents of the CDATA marked section will be reported through
     the characters handler.

 -- Method: LexicalHandler.endCDATA ()

     Reports the end of a CDATA marked section.


File: python.info,  Node: xml sax saxutils — SAX Utilities,  Next: xml sax xmlreader — Interface for XML parsers,  Prev: xml sax handler — Base classes for SAX handlers,  Up: Structured Markup Processing Tools

5.21.11 ‘xml.sax.saxutils’ — SAX Utilities
------------------------------------------

'Source code:' Lib/xml/sax/saxutils.py(1)

__________________________________________________________________

The module ‘xml.sax.saxutils’ contains a number of classes and functions
that are commonly useful when creating SAX applications, either in
direct use, or as base classes.

 -- Function: xml.sax.saxutils.escape (data, entities={})

     Escape ‘'&'’, ‘'<'’, and ‘'>'’ in a string of data.

     You can escape other strings of data by passing a dictionary as the
     optional 'entities' parameter.  The keys and values must all be
     strings; each key will be replaced with its corresponding value.
     The characters ‘'&'’, ‘'<'’ and ‘'>'’ are always escaped, even if
     'entities' is provided.

          Note: This function should only be used to escape characters
          that can’t be used directly in XML. Do not use this function
          as a general string translation function.

 -- Function: xml.sax.saxutils.unescape (data, entities={})

     Unescape ‘'&amp;'’, ‘'&lt;'’, and ‘'&gt;'’ in a string of data.

     You can unescape other strings of data by passing a dictionary as
     the optional 'entities' parameter.  The keys and values must all be
     strings; each key will be replaced with its corresponding value.
     ‘'&amp;'’, ‘'&lt;'’, and ‘'&gt;'’ are always unescaped, even if
     'entities' is provided.

 -- Function: xml.sax.saxutils.quoteattr (data, entities={})

     Similar to *note escape(): 3ae7, but also prepares 'data' to be
     used as an attribute value.  The return value is a quoted version
     of 'data' with any additional required replacements.  ‘quoteattr()’
     will select a quote character based on the content of 'data',
     attempting to avoid encoding any quote characters in the string.
     If both single- and double-quote characters are already in 'data',
     the double-quote characters will be encoded and 'data' will be
     wrapped in double-quotes.  The resulting string can be used
     directly as an attribute value:

          >>> print("<element attr=%s>" % quoteattr("ab ' cd \" ef"))
          <element attr="ab ' cd &quot; ef">

     This function is useful when generating attribute values for HTML
     or any SGML using the reference concrete syntax.

 -- Class: xml.sax.saxutils.XMLGenerator (out=None,
          encoding='iso-8859-1', short_empty_elements=False)

     This class implements the *note ContentHandler: 3a9b. interface by
     writing SAX events back into an XML document.  In other words,
     using an ‘XMLGenerator’ as the content handler will reproduce the
     original document being parsed.  'out' should be a file-like object
     which will default to 'sys.stdout'.  'encoding' is the encoding of
     the output stream which defaults to ‘'iso-8859-1'’.
     'short_empty_elements' controls the formatting of elements that
     contain no content: if ‘False’ (the default) they are emitted as a
     pair of start/end tags, if set to ‘True’ they are emitted as a
     single self-closed tag.

     Changed in version 3.2: Added the 'short_empty_elements' parameter.

 -- Class: xml.sax.saxutils.XMLFilterBase (base)

     This class is designed to sit between an *note XMLReader: 3a9e. and
     the client application’s event handlers.  By default, it does
     nothing but pass requests up to the reader and events on to the
     handlers unmodified, but subclasses can override specific methods
     to modify the event stream or the configuration requests as they
     pass through.

 -- Function: xml.sax.saxutils.prepare_input_source (source, base='')

     This function takes an input source and an optional base URL and
     returns a fully resolved *note InputSource: ecf. object ready for
     reading.  The input source can be given as a string, a file-like
     object, or an ‘InputSource’ object; parsers will use this function
     to implement the polymorphic 'source' argument to their *note
     parse(): 3aed. method.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/sax/saxutils.py


File: python.info,  Node: xml sax xmlreader — Interface for XML parsers,  Next: xml parsers expat — Fast XML parsing using Expat,  Prev: xml sax saxutils — SAX Utilities,  Up: Structured Markup Processing Tools

5.21.12 ‘xml.sax.xmlreader’ — Interface for XML parsers
-------------------------------------------------------

'Source code:' Lib/xml/sax/xmlreader.py(1)

__________________________________________________________________

SAX parsers implement the *note XMLReader: 3a9e. interface.  They are
implemented in a Python module, which must provide a function
‘create_parser()’.  This function is invoked by *note
xml.sax.make_parser(): 1bcb. with no arguments to create a new parser
object.

 -- Class: xml.sax.xmlreader.XMLReader

     Base class which can be inherited by SAX parsers.

 -- Class: xml.sax.xmlreader.IncrementalParser

     In some cases, it is desirable not to parse an input source at
     once, but to feed chunks of the document as they get available.
     Note that the reader will normally not read the entire file, but
     read it in chunks as well; still ‘parse()’ won’t return until the
     entire document is processed.  So these interfaces should be used
     if the blocking behaviour of ‘parse()’ is not desirable.

     When the parser is instantiated it is ready to begin accepting data
     from the feed method immediately.  After parsing has been finished
     with a call to close the reset method must be called to make the
     parser ready to accept new data, either from feed or using the
     parse method.

     Note that these methods must 'not' be called during parsing, that
     is, after parse has been called and before it returns.

     By default, the class also implements the parse method of the
     XMLReader interface using the feed, close and reset methods of the
     IncrementalParser interface as a convenience to SAX 2.0 driver
     writers.

 -- Class: xml.sax.xmlreader.Locator

     Interface for associating a SAX event with a document location.  A
     locator object will return valid results only during calls to
     DocumentHandler methods; at any other time, the results are
     unpredictable.  If information is not available, methods may return
     ‘None’.

 -- Class: xml.sax.xmlreader.InputSource (system_id=None)

     Encapsulation of the information needed by the *note XMLReader:
     3a9e. to read entities.

     This class may include information about the public identifier,
     system identifier, byte stream (possibly with character encoding
     information) and/or the character stream of an entity.

     Applications will create objects of this class for use in the *note
     XMLReader.parse(): 3aed. method and for returning from
     EntityResolver.resolveEntity.

     An ‘InputSource’ belongs to the application, the *note XMLReader:
     3a9e. is not allowed to modify ‘InputSource’ objects passed to it
     from the application, although it may make copies and modify those.

 -- Class: xml.sax.xmlreader.AttributesImpl (attrs)

     This is an implementation of the ‘Attributes’ interface (see
     section *note The Attributes Interface: 3aca.).  This is a
     dictionary-like object which represents the element attributes in a
     ‘startElement()’ call.  In addition to the most useful dictionary
     operations, it supports a number of other methods as described by
     the interface.  Objects of this class should be instantiated by
     readers; 'attrs' must be a dictionary-like object containing a
     mapping from attribute names to attribute values.

 -- Class: xml.sax.xmlreader.AttributesNSImpl (attrs, qnames)

     Namespace-aware variant of *note AttributesImpl: 3af2, which will
     be passed to ‘startElementNS()’.  It is derived from
     ‘AttributesImpl’, but understands attribute names as two-tuples of
     'namespaceURI' and 'localname'.  In addition, it provides a number
     of methods expecting qualified names as they appear in the original
     document.  This class implements the ‘AttributesNS’ interface (see
     section *note The AttributesNS Interface: 3acc.).

* Menu:

* XMLReader Objects::
* IncrementalParser Objects::
* Locator Objects::
* InputSource Objects::
* The Attributes Interface::
* The AttributesNS Interface::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/xml/sax/xmlreader.py


File: python.info,  Node: XMLReader Objects,  Next: IncrementalParser Objects,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.1 XMLReader Objects
...........................

The *note XMLReader: 3a9e. interface supports the following methods:

 -- Method: XMLReader.parse (source)

     Process an input source, producing SAX events.  The 'source' object
     can be a system identifier (a string identifying the input source –
     typically a file name or a URL), a *note pathlib.Path: 229. or
     *note path-like: 2a0. object, or an *note InputSource: ecf. object.
     When ‘parse()’ returns, the input is completely processed, and the
     parser object can be discarded or reset.

     Changed in version 3.5: Added support of character streams.

     Changed in version 3.8: Added support of path-like objects.

 -- Method: XMLReader.getContentHandler ()

     Return the current *note ContentHandler: 3a9b.

 -- Method: XMLReader.setContentHandler (handler)

     Set the current *note ContentHandler: 3a9b.  If no ‘ContentHandler’
     is set, content events will be discarded.

 -- Method: XMLReader.getDTDHandler ()

     Return the current *note DTDHandler: 3ab6.

 -- Method: XMLReader.setDTDHandler (handler)

     Set the current *note DTDHandler: 3ab6.  If no ‘DTDHandler’ is set,
     DTD events will be discarded.

 -- Method: XMLReader.getEntityResolver ()

     Return the current *note EntityResolver: 3ab7.

 -- Method: XMLReader.setEntityResolver (handler)

     Set the current *note EntityResolver: 3ab7.  If no ‘EntityResolver’
     is set, attempts to resolve an external entity will result in
     opening the system identifier for the entity, and fail if it is not
     available.

 -- Method: XMLReader.getErrorHandler ()

     Return the current *note ErrorHandler: 3aa9.

 -- Method: XMLReader.setErrorHandler (handler)

     Set the current error handler.  If no *note ErrorHandler: 3aa9. is
     set, errors will be raised as exceptions, and warnings will be
     printed.

 -- Method: XMLReader.setLocale (locale)

     Allow an application to set the locale for errors and warnings.

     SAX parsers are not required to provide localization for errors and
     warnings; if they cannot support the requested locale, however,
     they must raise a SAX exception.  Applications may request a locale
     change in the middle of a parse.

 -- Method: XMLReader.getFeature (featurename)

     Return the current setting for feature 'featurename'.  If the
     feature is not recognized, ‘SAXNotRecognizedException’ is raised.
     The well-known featurenames are listed in the module *note
     xml.sax.handler: 12a.

 -- Method: XMLReader.setFeature (featurename, value)

     Set the 'featurename' to 'value'.  If the feature is not
     recognized, ‘SAXNotRecognizedException’ is raised.  If the feature
     or its setting is not supported by the parser,
     'SAXNotSupportedException' is raised.

 -- Method: XMLReader.getProperty (propertyname)

     Return the current setting for property 'propertyname'.  If the
     property is not recognized, a ‘SAXNotRecognizedException’ is
     raised.  The well-known propertynames are listed in the module
     *note xml.sax.handler: 12a.

 -- Method: XMLReader.setProperty (propertyname, value)

     Set the 'propertyname' to 'value'.  If the property is not
     recognized, ‘SAXNotRecognizedException’ is raised.  If the property
     or its setting is not supported by the parser,
     'SAXNotSupportedException' is raised.


File: python.info,  Node: IncrementalParser Objects,  Next: Locator Objects,  Prev: XMLReader Objects,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.2 IncrementalParser Objects
...................................

Instances of *note IncrementalParser: 3af1. offer the following
additional methods:

 -- Method: IncrementalParser.feed (data)

     Process a chunk of 'data'.

 -- Method: IncrementalParser.close ()

     Assume the end of the document.  That will check well-formedness
     conditions that can be checked only at the end, invoke handlers,
     and may clean up resources allocated during parsing.

 -- Method: IncrementalParser.reset ()

     This method is called after close has been called to reset the
     parser so that it is ready to parse new documents.  The results of
     calling parse or feed after close without calling reset are
     undefined.


File: python.info,  Node: Locator Objects,  Next: InputSource Objects,  Prev: IncrementalParser Objects,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.3 Locator Objects
.........................

Instances of *note Locator: 3aab. provide these methods:

 -- Method: Locator.getColumnNumber ()

     Return the column number where the current event begins.

 -- Method: Locator.getLineNumber ()

     Return the line number where the current event begins.

 -- Method: Locator.getPublicId ()

     Return the public identifier for the current event.

 -- Method: Locator.getSystemId ()

     Return the system identifier for the current event.


File: python.info,  Node: InputSource Objects,  Next: The Attributes Interface,  Prev: Locator Objects,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.4 InputSource Objects
.............................

 -- Method: InputSource.setPublicId (id)

     Sets the public identifier of this *note InputSource: ecf.

 -- Method: InputSource.getPublicId ()

     Returns the public identifier of this *note InputSource: ecf.

 -- Method: InputSource.setSystemId (id)

     Sets the system identifier of this *note InputSource: ecf.

 -- Method: InputSource.getSystemId ()

     Returns the system identifier of this *note InputSource: ecf.

 -- Method: InputSource.setEncoding (encoding)

     Sets the character encoding of this *note InputSource: ecf.

     The encoding must be a string acceptable for an XML encoding
     declaration (see section 4.3.3 of the XML recommendation).

     The encoding attribute of the *note InputSource: ecf. is ignored if
     the ‘InputSource’ also contains a character stream.

 -- Method: InputSource.getEncoding ()

     Get the character encoding of this InputSource.

 -- Method: InputSource.setByteStream (bytefile)

     Set the byte stream (a *note binary file: 1e26.) for this input
     source.

     The SAX parser will ignore this if there is also a character stream
     specified, but it will use a byte stream in preference to opening a
     URI connection itself.

     If the application knows the character encoding of the byte stream,
     it should set it with the setEncoding method.

 -- Method: InputSource.getByteStream ()

     Get the byte stream for this input source.

     The getEncoding method will return the character encoding for this
     byte stream, or ‘None’ if unknown.

 -- Method: InputSource.setCharacterStream (charfile)

     Set the character stream (a *note text file: 1e25.) for this input
     source.

     If there is a character stream specified, the SAX parser will
     ignore any byte stream and will not attempt to open a URI
     connection to the system identifier.

 -- Method: InputSource.getCharacterStream ()

     Get the character stream for this input source.


File: python.info,  Node: The Attributes Interface,  Next: The AttributesNS Interface,  Prev: InputSource Objects,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.5 The ‘Attributes’ Interface
....................................

‘Attributes’ objects implement a portion of the *note mapping protocol:
1200, including the methods ‘copy()’, ‘get()’, *note __contains__():
1406, ‘items()’, ‘keys()’, and ‘values()’.  The following methods are
also provided:

 -- Method: Attributes.getLength ()

     Return the number of attributes.

 -- Method: Attributes.getNames ()

     Return the names of the attributes.

 -- Method: Attributes.getType (name)

     Returns the type of the attribute 'name', which is normally
     ‘'CDATA'’.

 -- Method: Attributes.getValue (name)

     Return the value of attribute 'name'.


File: python.info,  Node: The AttributesNS Interface,  Prev: The Attributes Interface,  Up: xml sax xmlreader — Interface for XML parsers

5.21.12.6 The ‘AttributesNS’ Interface
......................................

This interface is a subtype of the ‘Attributes’ interface (see section
*note The Attributes Interface: 3aca.).  All methods supported by that
interface are also available on ‘AttributesNS’ objects.

The following methods are also available:

 -- Method: AttributesNS.getValueByQName (name)

     Return the value for a qualified name.

 -- Method: AttributesNS.getNameByQName (name)

     Return the ‘(namespace, localname)’ pair for a qualified 'name'.

 -- Method: AttributesNS.getQNameByName (name)

     Return the qualified name for a ‘(namespace, localname)’ pair.

 -- Method: AttributesNS.getQNames ()

     Return the qualified names of all attributes.


File: python.info,  Node: xml parsers expat — Fast XML parsing using Expat,  Prev: xml sax xmlreader — Interface for XML parsers,  Up: Structured Markup Processing Tools

5.21.13 ‘xml.parsers.expat’ — Fast XML parsing using Expat
----------------------------------------------------------

__________________________________________________________________

     Note: If you need to parse untrusted or unauthenticated data, see
     *note XML security: 39b7.

The ‘xml.parsers.expat’ module is a Python interface to the Expat
non-validating XML parser.  The module provides a single extension type,
‘xmlparser’, that represents the current state of an XML parser.  After
an ‘xmlparser’ object has been created, various attributes of the object
can be set to handler functions.  When an XML document is then fed to
the parser, the handler functions are called for the character data and
markup in the XML document.

This module uses the ‘pyexpat’ module to provide access to the Expat
parser.  Direct use of the ‘pyexpat’ module is deprecated.

This module provides one exception and one type object:

 -- Exception: xml.parsers.expat.ExpatError

     The exception raised when Expat reports an error.  See section
     *note ExpatError Exceptions: 3b26. for more information on
     interpreting Expat errors.

 -- Exception: xml.parsers.expat.error

     Alias for *note ExpatError: 12bf.

 -- Data: xml.parsers.expat.XMLParserType

     The type of the return values from the *note ParserCreate(): 3b29.
     function.

The ‘xml.parsers.expat’ module contains two functions:

 -- Function: xml.parsers.expat.ErrorString (errno)

     Returns an explanatory string for a given error number 'errno'.

 -- Function: xml.parsers.expat.ParserCreate (encoding=None,
          namespace_separator=None)

     Creates and returns a new ‘xmlparser’ object.  'encoding', if
     specified, must be a string naming the encoding used by the XML
     data.  Expat doesn’t support as many encodings as Python does, and
     its repertoire of encodings can’t be extended; it supports UTF-8,
     UTF-16, ISO-8859-1 (Latin1), and ASCII. If 'encoding' (1) is given
     it will override the implicit or explicit encoding of the document.
     Parsers created through ‘ParserCreate()’ are called “root” parsers,
     in the sense that they do not have any parent parser attached.
     Non-root parsers are created by *note
     parser.ExternalEntityParserCreate: 15b0.

     Expat can optionally do XML namespace processing for you, enabled
     by providing a value for 'namespace_separator'.  The value must be
     a one-character string; a *note ValueError: 202. will be raised if
     the string has an illegal length (‘None’ is considered the same as
     omission).  When namespace processing is enabled, element type
     names and attribute names that belong to a namespace will be
     expanded.  The element name passed to the element handlers
     ‘StartElementHandler’ and ‘EndElementHandler’ will be the
     concatenation of the namespace URI, the namespace separator
     character, and the local part of the name.  If the namespace
     separator is a zero byte (‘chr(0)’) then the namespace URI and the
     local part will be concatenated without any separator.

     For example, if 'namespace_separator' is set to a space character
     (‘' '’) and the following document is parsed:

          <?xml version="1.0"?>
          <root xmlns    = "http://default-namespace.org/"
                xmlns:py = "http://www.python.org/ns/">
            <py:elem1 />
            <elem2 xmlns="" />
          </root>

     ‘StartElementHandler’ will receive the following strings for each
     element:

          http://default-namespace.org/ root
          http://www.python.org/ns/ elem1
          elem2

     Due to limitations in the ‘Expat’ library used by ‘pyexpat’, the
     ‘xmlparser’ instance returned can only be used to parse a single
     XML document.  Call ‘ParserCreate’ for each document to provide
     unique parser instances.

See also
........

The Expat XML Parser(2)

     Home page of the Expat project.

* Menu:

* XMLParser Objects: XMLParser Objects<2>.
* ExpatError Exceptions::
* Example: Example<10>.
* Content Model Descriptions::
* Expat error constants::

   ---------- Footnotes ----------

   (1) The encoding string included in XML output should conform to the
appropriate standards.  For example, “UTF-8” is valid, but “UTF8” is
not.  See
‘https://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl’ and
‘https://www.iana.org/assignments/character-sets/character-sets.xhtml’.

   (2) http://www.libexpat.org/


File: python.info,  Node: XMLParser Objects<2>,  Next: ExpatError Exceptions,  Up: xml parsers expat — Fast XML parsing using Expat

5.21.13.1 XMLParser Objects
...........................

‘xmlparser’ objects have the following methods:

 -- Method: xmlparser.Parse (data[, isfinal])

     Parses the contents of the string 'data', calling the appropriate
     handler functions to process the parsed data.  'isfinal' must be
     true on the final call to this method; it allows the parsing of a
     single file in fragments, not the submission of multiple files.
     'data' can be the empty string at any time.

 -- Method: xmlparser.ParseFile (file)

     Parse XML data reading from the object 'file'.  'file' only needs
     to provide the ‘read(nbytes)’ method, returning the empty string
     when there’s no more data.

 -- Method: xmlparser.SetBase (base)

     Sets the base to be used for resolving relative URIs in system
     identifiers in declarations.  Resolving relative identifiers is
     left to the application: this value will be passed through as the
     'base' argument to the *note ExternalEntityRefHandler(): 3b30,
     *note NotationDeclHandler(): 3b31, and *note
     UnparsedEntityDeclHandler(): 3b32. functions.

 -- Method: xmlparser.GetBase ()

     Returns a string containing the base set by a previous call to
     *note SetBase(): 3b2f, or ‘None’ if ‘SetBase()’ hasn’t been called.

 -- Method: xmlparser.GetInputContext ()

     Returns the input data that generated the current event as a
     string.  The data is in the encoding of the entity which contains
     the text.  When called while an event handler is not active, the
     return value is ‘None’.

 -- Method: xmlparser.ExternalEntityParserCreate (context[, encoding])

     Create a “child” parser which can be used to parse an external
     parsed entity referred to by content parsed by the parent parser.
     The 'context' parameter should be the string passed to the *note
     ExternalEntityRefHandler(): 3b30. handler function, described
     below.  The child parser is created with the *note
     ordered_attributes: 3b35. and *note specified_attributes: 3b36. set
     to the values of this parser.

 -- Method: xmlparser.SetParamEntityParsing (flag)

     Control parsing of parameter entities (including the external DTD
     subset).  Possible 'flag' values are
     ‘XML_PARAM_ENTITY_PARSING_NEVER’,
     ‘XML_PARAM_ENTITY_PARSING_UNLESS_STANDALONE’ and
     ‘XML_PARAM_ENTITY_PARSING_ALWAYS’.  Return true if setting the flag
     was successful.

 -- Method: xmlparser.UseForeignDTD ([flag])

     Calling this with a true value for 'flag' (the default) will cause
     Expat to call the *note ExternalEntityRefHandler: 3b30. with *note
     None: 678. for all arguments to allow an alternate DTD to be
     loaded.  If the document does not contain a document type
     declaration, the ‘ExternalEntityRefHandler’ will still be called,
     but the *note StartDoctypeDeclHandler: 3b39. and *note
     EndDoctypeDeclHandler: 3b3a. will not be called.

     Passing a false value for 'flag' will cancel a previous call that
     passed a true value, but otherwise has no effect.

     This method can only be called before the *note Parse(): 3b2d. or
     *note ParseFile(): 3b2e. methods are called; calling it after
     either of those have been called causes *note ExpatError: 12bf. to
     be raised with the *note code: 1a. attribute set to
     ‘errors.codes[errors.XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING]’.

 -- Method: xmlparser.SetReparseDeferralEnabled (enabled)

          Warning: Calling ‘SetReparseDeferralEnabled(False)’ has
          security implications, as detailed below; please make sure to
          understand these consequences prior to using the
          ‘SetReparseDeferralEnabled’ method.

     Expat 2.6.0 introduced a security mechanism called “reparse
     deferral” where instead of causing denial of service through
     quadratic runtime from reparsing large tokens, reparsing of
     unfinished tokens is now delayed by default until a sufficient
     amount of input is reached.  Due to this delay, registered handlers
     may — depending of the sizing of input chunks pushed to Expat — no
     longer be called right after pushing new input to the parser.
     Where immediate feedback and taking over responsibility of
     protecting against denial of service from large tokens are both
     wanted, calling ‘SetReparseDeferralEnabled(False)’ disables reparse
     deferral for the current Expat parser instance, temporarily or
     altogether.  Calling ‘SetReparseDeferralEnabled(True)’ allows
     re-enabling reparse deferral.

     Note that ‘SetReparseDeferralEnabled()’ has been backported to some
     prior releases of CPython as a security fix.  Check for
     availability of ‘SetReparseDeferralEnabled()’ using *note
     hasattr(): 4d5. if used in code running across a variety of Python
     versions.

     Added in version 3.13.

 -- Method: xmlparser.GetReparseDeferralEnabled ()

     Returns whether reparse deferral is currently enabled for the given
     Expat parser instance.

     Added in version 3.13.

‘xmlparser’ objects have the following methods to mitigate some common
XML vulnerabilities.

 -- Method: xmlparser.SetAllocTrackerActivationThreshold (threshold, /)

     Sets the number of allocated bytes of dynamic memory needed to
     activate protection against disproportionate use of RAM.

     By default, parser objects have an allocation activation threshold
     of 64 MiB, or equivalently 67,108,864 bytes.

     An *note ExpatError: 12bf. is raised if this method is called on a
     *note non-root: 3b2b. parser.  The corresponding *note lineno:
     3b3b. and *note offset: 3b3c. should not be used as they may have
     no special meaning.

     Added in version 3.13.10.

 -- Method: xmlparser.SetAllocTrackerMaximumAmplification (max_factor,
          /)

     Sets the maximum amplification factor between direct input and
     bytes of dynamic memory allocated.

     The amplification factor is calculated as ‘allocated / direct’
     while parsing, where ‘direct’ is the number of bytes read from the
     primary document in parsing and ‘allocated’ is the number of bytes
     of dynamic memory allocated in the parser hierarchy.

     The 'max_factor' value must be a non-NaN *note float: 2f7. value
     greater than or equal to 1.0.  Amplification factors greater than
     100.0 can be observed near the start of parsing even with benign
     files in practice.  In particular, the activation threshold should
     be carefully chosen to avoid false positives.

     By default, parser objects have a maximum amplification factor of
     100.0.

     An *note ExpatError: 12bf. is raised if this method is called on a
     *note non-root: 3b2b. parser or if 'max_factor' is outside the
     valid range.  The corresponding *note lineno: 3b3b. and *note
     offset: 3b3c. should not be used as they may have no special
     meaning.

          Note: The maximum amplification factor is only considered if
          the threshold that can be adjusted by *note
          SetAllocTrackerActivationThreshold(): 15fd. is exceeded.

     Added in version 3.13.10.

‘xmlparser’ objects have the following attributes:

 -- Attribute: xmlparser.buffer_size

     The size of the buffer used when *note buffer_text: 1511. is true.
     A new buffer size can be set by assigning a new integer value to
     this attribute.  When the size is changed, the buffer will be
     flushed.

 -- Attribute: xmlparser.buffer_text

     Setting this to true causes the ‘xmlparser’ object to buffer
     textual content returned by Expat to avoid multiple calls to the
     *note CharacterDataHandler(): 3b3e. callback whenever possible.
     This can improve performance substantially since Expat normally
     breaks character data into chunks at every line ending.  This
     attribute is false by default, and may be changed at any time.
     Note that when it is false, data that does not contain newlines may
     be chunked too.

 -- Attribute: xmlparser.buffer_used

     If *note buffer_text: 1511. is enabled, the number of bytes stored
     in the buffer.  These bytes represent UTF-8 encoded text.  This
     attribute has no meaningful interpretation when ‘buffer_text’ is
     false.

 -- Attribute: xmlparser.ordered_attributes

     Setting this attribute to a non-zero integer causes the attributes
     to be reported as a list rather than a dictionary.  The attributes
     are presented in the order found in the document text.  For each
     attribute, two list entries are presented: the attribute name and
     the attribute value.  (Older versions of this module also used this
     format.)  By default, this attribute is false; it may be changed at
     any time.

 -- Attribute: xmlparser.specified_attributes

     If set to a non-zero integer, the parser will report only those
     attributes which were specified in the document instance and not
     those which were derived from attribute declarations.  Applications
     which set this need to be especially careful to use what additional
     information is available from the declarations as needed to comply
     with the standards for the behavior of XML processors.  By default,
     this attribute is false; it may be changed at any time.

The following attributes contain values relating to the most recent
error encountered by an ‘xmlparser’ object, and will only have correct
values once a call to ‘Parse()’ or ‘ParseFile()’ has raised an *note
xml.parsers.expat.ExpatError: 12bf. exception.

 -- Attribute: xmlparser.ErrorByteIndex

     Byte index at which an error occurred.

 -- Attribute: xmlparser.ErrorCode

     Numeric code specifying the problem.  This value can be passed to
     the *note ErrorString(): 3b2a. function, or compared to one of the
     constants defined in the ‘errors’ object.

 -- Attribute: xmlparser.ErrorColumnNumber

     Column number at which an error occurred.

 -- Attribute: xmlparser.ErrorLineNumber

     Line number at which an error occurred.

The following attributes contain values relating to the current parse
location in an ‘xmlparser’ object.  During a callback reporting a parse
event they indicate the location of the first of the sequence of
characters that generated the event.  When called outside of a callback,
the position indicated will be just past the last parse event
(regardless of whether there was an associated callback).

 -- Attribute: xmlparser.CurrentByteIndex

     Current byte index in the parser input.

 -- Attribute: xmlparser.CurrentColumnNumber

     Current column number in the parser input.

 -- Attribute: xmlparser.CurrentLineNumber

     Current line number in the parser input.

Here is the list of handlers that can be set.  To set a handler on an
‘xmlparser’ object 'o', use ‘o.handlername = func’.  'handlername' must
be taken from the following list, and 'func' must be a callable object
accepting the correct number of arguments.  The arguments are all
strings, unless otherwise stated.

 -- Method: xmlparser.XmlDeclHandler (version, encoding, standalone)

     Called when the XML declaration is parsed.  The XML declaration is
     the (optional) declaration of the applicable version of the XML
     recommendation, the encoding of the document text, and an optional
     “standalone” declaration.  'version' and 'encoding' will be
     strings, and 'standalone' will be ‘1’ if the document is declared
     standalone, ‘0’ if it is declared not to be standalone, or ‘-1’ if
     the standalone clause was omitted.  This is only available with
     Expat version 1.95.0 or newer.

 -- Method: xmlparser.StartDoctypeDeclHandler (doctypeName, systemId,
          publicId, has_internal_subset)

     Called when Expat begins parsing the document type declaration
     (‘<!DOCTYPE ...’).  The 'doctypeName' is provided exactly as
     presented.  The 'systemId' and 'publicId' parameters give the
     system and public identifiers if specified, or ‘None’ if omitted.
     'has_internal_subset' will be true if the document contains an
     internal document declaration subset.  This requires Expat version
     1.2 or newer.

 -- Method: xmlparser.EndDoctypeDeclHandler ()

     Called when Expat is done parsing the document type declaration.
     This requires Expat version 1.2 or newer.

 -- Method: xmlparser.ElementDeclHandler (name, model)

     Called once for each element type declaration.  'name' is the name
     of the element type, and 'model' is a representation of the content
     model.

 -- Method: xmlparser.AttlistDeclHandler (elname, attname, type,
          default, required)

     Called for each declared attribute for an element type.  If an
     attribute list declaration declares three attributes, this handler
     is called three times, once for each attribute.  'elname' is the
     name of the element to which the declaration applies and 'attname'
     is the name of the attribute declared.  The attribute type is a
     string passed as 'type'; the possible values are ‘'CDATA'’, ‘'ID'’,
     ‘'IDREF'’, … 'default' gives the default value for the attribute
     used when the attribute is not specified by the document instance,
     or ‘None’ if there is no default value (‘#IMPLIED’ values).  If the
     attribute is required to be given in the document instance,
     'required' will be true.  This requires Expat version 1.95.0 or
     newer.

 -- Method: xmlparser.StartElementHandler (name, attributes)

     Called for the start of every element.  'name' is a string
     containing the element name, and 'attributes' is the element
     attributes.  If *note ordered_attributes: 3b35. is true, this is a
     list (see ‘ordered_attributes’ for a full description).  Otherwise
     it’s a dictionary mapping names to values.

 -- Method: xmlparser.EndElementHandler (name)

     Called for the end of every element.

 -- Method: xmlparser.ProcessingInstructionHandler (target, data)

     Called for every processing instruction.

 -- Method: xmlparser.CharacterDataHandler (data)

     Called for character data.  This will be called for normal
     character data, CDATA marked content, and ignorable whitespace.
     Applications which must distinguish these cases can use the *note
     StartCdataSectionHandler: 3b4c, *note EndCdataSectionHandler: 3b4d,
     and *note ElementDeclHandler: 15a5. callbacks to collect the
     required information.  Note that the character data may be chunked
     even if it is short and so you may receive more than one call to
     ‘CharacterDataHandler()’.  Set the *note buffer_text: 1511.
     instance attribute to ‘True’ to avoid that.

 -- Method: xmlparser.UnparsedEntityDeclHandler (entityName, base,
          systemId, publicId, notationName)

     Called for unparsed (NDATA) entity declarations.  This is only
     present for version 1.2 of the Expat library; for more recent
     versions, use *note EntityDeclHandler: 3b4e. instead.  (The
     underlying function in the Expat library has been declared
     obsolete.)

 -- Method: xmlparser.EntityDeclHandler (entityName,
          is_parameter_entity, value, base, systemId, publicId,
          notationName)

     Called for all entity declarations.  For parameter and internal
     entities, 'value' will be a string giving the declared contents of
     the entity; this will be ‘None’ for external entities.  The
     'notationName' parameter will be ‘None’ for parsed entities, and
     the name of the notation for unparsed entities.
     'is_parameter_entity' will be true if the entity is a parameter
     entity or false for general entities (most applications only need
     to be concerned with general entities).  This is only available
     starting with version 1.95.0 of the Expat library.

 -- Method: xmlparser.NotationDeclHandler (notationName, base, systemId,
          publicId)

     Called for notation declarations.  'notationName', 'base', and
     'systemId', and 'publicId' are strings if given.  If the public
     identifier is omitted, 'publicId' will be ‘None’.

 -- Method: xmlparser.StartNamespaceDeclHandler (prefix, uri)

     Called when an element contains a namespace declaration.  Namespace
     declarations are processed before the *note StartElementHandler:
     3b49. is called for the element on which declarations are placed.

 -- Method: xmlparser.EndNamespaceDeclHandler (prefix)

     Called when the closing tag is reached for an element that
     contained a namespace declaration.  This is called once for each
     namespace declaration on the element in the reverse of the order
     for which the *note StartNamespaceDeclHandler: 3b4f. was called to
     indicate the start of each namespace declaration’s scope.  Calls to
     this handler are made after the corresponding *note
     EndElementHandler: 3b4a. for the end of the element.

 -- Method: xmlparser.CommentHandler (data)

     Called for comments.  'data' is the text of the comment, excluding
     the leading ‘'<!-’‘-'’ and trailing ‘'-’‘->'’.

 -- Method: xmlparser.StartCdataSectionHandler ()

     Called at the start of a CDATA section.  This and *note
     EndCdataSectionHandler: 3b4d. are needed to be able to identify the
     syntactical start and end for CDATA sections.

 -- Method: xmlparser.EndCdataSectionHandler ()

     Called at the end of a CDATA section.

 -- Method: xmlparser.DefaultHandler (data)

     Called for any characters in the XML document for which no
     applicable handler has been specified.  This means characters that
     are part of a construct which could be reported, but for which no
     handler has been supplied.

 -- Method: xmlparser.DefaultHandlerExpand (data)

     This is the same as the *note DefaultHandler(): 3b52, but doesn’t
     inhibit expansion of internal entities.  The entity reference will
     not be passed to the default handler.

 -- Method: xmlparser.NotStandaloneHandler ()

     Called if the XML document hasn’t been declared as being a
     standalone document.  This happens when there is an external subset
     or a reference to a parameter entity, but the XML declaration does
     not set standalone to ‘yes’ in an XML declaration.  If this handler
     returns ‘0’, then the parser will raise an
     ‘XML_ERROR_NOT_STANDALONE’ error.  If this handler is not set, no
     exception is raised by the parser for this condition.

 -- Method: xmlparser.ExternalEntityRefHandler (context, base, systemId,
          publicId)

          Warning: Implementing a handler that accesses local files
          and/or the network may create a vulnerability to external
          entity attacks(1) if ‘xmlparser’ is used with user-provided
          XML content.  Please reflect on your threat model(2) before
          implementing this handler.

     Called for references to external entities.  'base' is the current
     base, as set by a previous call to *note SetBase(): 3b2f.  The
     public and system identifiers, 'systemId' and 'publicId', are
     strings if given; if the public identifier is not given, 'publicId'
     will be ‘None’.  The 'context' value is opaque and should only be
     used as described below.

     For external entities to be parsed, this handler must be
     implemented.  It is responsible for creating the sub-parser using
     ‘ExternalEntityParserCreate(context)’, initializing it with the
     appropriate callbacks, and parsing the entity.  This handler should
     return an integer; if it returns ‘0’, the parser will raise an
     ‘XML_ERROR_EXTERNAL_ENTITY_HANDLING’ error, otherwise parsing will
     continue.

     If this handler is not provided, external entities are reported by
     the *note DefaultHandler: 3b52. callback, if provided.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/XML_external_entity_attack

   (2) https://en.wikipedia.org/wiki/Threat_model


File: python.info,  Node: ExpatError Exceptions,  Next: Example<10>,  Prev: XMLParser Objects<2>,  Up: xml parsers expat — Fast XML parsing using Expat

5.21.13.2 ExpatError Exceptions
...............................

*note ExpatError: 12bf. exceptions have a number of interesting
attributes:

 -- Attribute: ExpatError.code

     Expat’s internal error number for the specific error.  The *note
     errors.messages: 3b57. dictionary maps these error numbers to
     Expat’s error messages.  For example:

          from xml.parsers.expat import ParserCreate, ExpatError, errors

          p = ParserCreate()
          try:
              p.Parse(some_xml_document)
          except ExpatError as err:
              print("Error:", errors.messages[err.code])

     The *note errors: 127. module also provides error message constants
     and a dictionary *note codes: 3b58. mapping these messages back to
     the error codes, see below.

 -- Attribute: ExpatError.lineno

     Line number on which the error was detected.  The first line is
     numbered ‘1’.

 -- Attribute: ExpatError.offset

     Character offset into the line where the error occurred.  The first
     column is numbered ‘0’.


File: python.info,  Node: Example<10>,  Next: Content Model Descriptions,  Prev: ExpatError Exceptions,  Up: xml parsers expat — Fast XML parsing using Expat

5.21.13.3 Example
.................

The following program defines three handlers that just print out their
arguments.

     import xml.parsers.expat

     # 3 handler functions
     def start_element(name, attrs):
         print('Start element:', name, attrs)
     def end_element(name):
         print('End element:', name)
     def char_data(data):
         print('Character data:', repr(data))

     p = xml.parsers.expat.ParserCreate()

     p.StartElementHandler = start_element
     p.EndElementHandler = end_element
     p.CharacterDataHandler = char_data

     p.Parse("""<?xml version="1.0"?>
     <parent id="top"><child1 name="paul">Text goes here</child1>
     <child2 name="fred">More text</child2>
     </parent>""", 1)

The output from this program is:

     Start element: parent {'id': 'top'}
     Start element: child1 {'name': 'paul'}
     Character data: 'Text goes here'
     End element: child1
     Character data: '\n'
     Start element: child2 {'name': 'fred'}
     Character data: 'More text'
     End element: child2
     Character data: '\n'
     End element: parent


File: python.info,  Node: Content Model Descriptions,  Next: Expat error constants,  Prev: Example<10>,  Up: xml parsers expat — Fast XML parsing using Expat

5.21.13.4 Content Model Descriptions
....................................

Content models are described using nested tuples.  Each tuple contains
four values: the type, the quantifier, the name, and a tuple of
children.  Children are simply additional content model descriptions.

The values of the first two fields are constants defined in the
‘xml.parsers.expat.model’ module.  These constants can be collected in
two groups: the model type group and the quantifier group.

The constants in the model type group are:

 -- Data: xml.parsers.expat.model.XML_CTYPE_ANY

     The element named by the model name was declared to have a content
     model of ‘ANY’.

 -- Data: xml.parsers.expat.model.XML_CTYPE_CHOICE

     The named element allows a choice from a number of options; this is
     used for content models such as ‘(A | B | C)’.

 -- Data: xml.parsers.expat.model.XML_CTYPE_EMPTY

     Elements which are declared to be ‘EMPTY’ have this model type.

 -- Data: xml.parsers.expat.model.XML_CTYPE_MIXED

 -- Data: xml.parsers.expat.model.XML_CTYPE_NAME

 -- Data: xml.parsers.expat.model.XML_CTYPE_SEQ

     Models which represent a series of models which follow one after
     the other are indicated with this model type.  This is used for
     models such as ‘(A, B, C)’.

The constants in the quantifier group are:

 -- Data: xml.parsers.expat.model.XML_CQUANT_NONE

     No modifier is given, so it can appear exactly once, as for ‘A’.

 -- Data: xml.parsers.expat.model.XML_CQUANT_OPT

     The model is optional: it can appear once or not at all, as for
     ‘A?’.

 -- Data: xml.parsers.expat.model.XML_CQUANT_PLUS

     The model must occur one or more times (like ‘A+’).

 -- Data: xml.parsers.expat.model.XML_CQUANT_REP

     The model must occur zero or more times, as for ‘A*’.


File: python.info,  Node: Expat error constants,  Prev: Content Model Descriptions,  Up: xml parsers expat — Fast XML parsing using Expat

5.21.13.5 Expat error constants
...............................

The following constants are provided in the ‘xml.parsers.expat.errors’
module.  These constants are useful in interpreting some of the
attributes of the ‘ExpatError’ exception objects raised when an error
has occurred.  Since for backwards compatibility reasons, the constants’
value is the error 'message' and not the numeric error 'code', you do
this by comparing its *note code: 1a. attribute with
‘errors.codes[errors.XML_ERROR_CONSTANT_NAME]’.

The ‘errors’ module has the following attributes:

 -- Data: xml.parsers.expat.errors.codes

     A dictionary mapping string descriptions to their error codes.

     Added in version 3.2.

 -- Data: xml.parsers.expat.errors.messages

     A dictionary mapping numeric error codes to their string
     descriptions.

     Added in version 3.2.

 -- Data: xml.parsers.expat.errors.XML_ERROR_ASYNC_ENTITY

 -- Data:
          xml.parsers.expat.errors.XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF

     An entity reference in an attribute value referred to an external
     entity instead of an internal entity.

 -- Data: xml.parsers.expat.errors.XML_ERROR_BAD_CHAR_REF

     A character reference referred to a character which is illegal in
     XML (for example, character ‘0’, or ‘‘&#0;’’).

 -- Data: xml.parsers.expat.errors.XML_ERROR_BINARY_ENTITY_REF

     An entity reference referred to an entity which was declared with a
     notation, so cannot be parsed.

 -- Data: xml.parsers.expat.errors.XML_ERROR_DUPLICATE_ATTRIBUTE

     An attribute was used more than once in a start tag.

 -- Data: xml.parsers.expat.errors.XML_ERROR_INCORRECT_ENCODING

 -- Data: xml.parsers.expat.errors.XML_ERROR_INVALID_TOKEN

     Raised when an input byte could not properly be assigned to a
     character; for example, a NUL byte (value ‘0’) in a UTF-8 input
     stream.

 -- Data: xml.parsers.expat.errors.XML_ERROR_JUNK_AFTER_DOC_ELEMENT

     Something other than whitespace occurred after the document
     element.

 -- Data: xml.parsers.expat.errors.XML_ERROR_MISPLACED_XML_PI

     An XML declaration was found somewhere other than the start of the
     input data.

 -- Data: xml.parsers.expat.errors.XML_ERROR_NO_ELEMENTS

     The document contains no elements (XML requires all documents to
     contain exactly one top-level element)..

 -- Data: xml.parsers.expat.errors.XML_ERROR_NO_MEMORY

     Expat was not able to allocate memory internally.

 -- Data: xml.parsers.expat.errors.XML_ERROR_PARAM_ENTITY_REF

     A parameter entity reference was found where it was not allowed.

 -- Data: xml.parsers.expat.errors.XML_ERROR_PARTIAL_CHAR

     An incomplete character was found in the input.

 -- Data: xml.parsers.expat.errors.XML_ERROR_RECURSIVE_ENTITY_REF

     An entity reference contained another reference to the same entity;
     possibly via a different name, and possibly indirectly.

 -- Data: xml.parsers.expat.errors.XML_ERROR_SYNTAX

     Some unspecified syntax error was encountered.

 -- Data: xml.parsers.expat.errors.XML_ERROR_TAG_MISMATCH

     An end tag did not match the innermost open start tag.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNCLOSED_TOKEN

     Some token (such as a start tag) was not closed before the end of
     the stream or the next token was encountered.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNDEFINED_ENTITY

     A reference was made to an entity which was not defined.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNKNOWN_ENCODING

     The document encoding is not supported by Expat.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNCLOSED_CDATA_SECTION

     A CDATA marked section was not closed.

 -- Data: xml.parsers.expat.errors.XML_ERROR_EXTERNAL_ENTITY_HANDLING

 -- Data: xml.parsers.expat.errors.XML_ERROR_NOT_STANDALONE

     The parser determined that the document was not “standalone” though
     it declared itself to be in the XML declaration, and the
     ‘NotStandaloneHandler’ was set and returned ‘0’.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNEXPECTED_STATE

 -- Data: xml.parsers.expat.errors.XML_ERROR_ENTITY_DECLARED_IN_PE

 -- Data: xml.parsers.expat.errors.XML_ERROR_FEATURE_REQUIRES_XML_DTD

     An operation was requested that requires DTD support to be compiled
     in, but Expat was configured without DTD support.  This should
     never be reported by a standard build of the ‘xml.parsers.expat’
     module.

 -- Data:
          xml.parsers.expat.errors.XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING

     A behavioral change was requested after parsing started that can
     only be changed before parsing has started.  This is (currently)
     only raised by ‘UseForeignDTD()’.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNBOUND_PREFIX

     An undeclared prefix was found when namespace processing was
     enabled.

 -- Data: xml.parsers.expat.errors.XML_ERROR_UNDECLARING_PREFIX

     The document attempted to remove the namespace declaration
     associated with a prefix.

 -- Data: xml.parsers.expat.errors.XML_ERROR_INCOMPLETE_PE

     A parameter entity contained incomplete markup.

 -- Data: xml.parsers.expat.errors.XML_ERROR_XML_DECL

     The document contained no document element at all.

 -- Data: xml.parsers.expat.errors.XML_ERROR_TEXT_DECL

     There was an error parsing a text declaration in an external
     entity.

 -- Data: xml.parsers.expat.errors.XML_ERROR_PUBLICID

     Characters were found in the public id that are not allowed.

 -- Data: xml.parsers.expat.errors.XML_ERROR_SUSPENDED

     The requested operation was made on a suspended parser, but isn’t
     allowed.  This includes attempts to provide additional input or to
     stop the parser.

 -- Data: xml.parsers.expat.errors.XML_ERROR_NOT_SUSPENDED

     An attempt to resume the parser was made when the parser had not
     been suspended.

 -- Data: xml.parsers.expat.errors.XML_ERROR_ABORTED

     This should not be reported to Python applications.

 -- Data: xml.parsers.expat.errors.XML_ERROR_FINISHED

     The requested operation was made on a parser which was finished
     parsing input, but isn’t allowed.  This includes attempts to
     provide additional input or to stop the parser.

 -- Data: xml.parsers.expat.errors.XML_ERROR_SUSPEND_PE

 -- Data: xml.parsers.expat.errors.XML_ERROR_RESERVED_PREFIX_XML

     An attempt was made to undeclare reserved namespace prefix ‘xml’ or
     to bind it to another namespace URI.

 -- Data: xml.parsers.expat.errors.XML_ERROR_RESERVED_PREFIX_XMLNS

     An attempt was made to declare or undeclare reserved namespace
     prefix ‘xmlns’.

 -- Data: xml.parsers.expat.errors.XML_ERROR_RESERVED_NAMESPACE_URI

     An attempt was made to bind the URI of one the reserved namespace
     prefixes ‘xml’ and ‘xmlns’ to another namespace prefix.

 -- Data: xml.parsers.expat.errors.XML_ERROR_INVALID_ARGUMENT

     This should not be reported to Python applications.

 -- Data: xml.parsers.expat.errors.XML_ERROR_NO_BUFFER

     This should not be reported to Python applications.

 -- Data: xml.parsers.expat.errors.XML_ERROR_AMPLIFICATION_LIMIT_BREACH

     The limit on input amplification factor (from DTD and entities) has
     been breached.


File: python.info,  Node: Internet Protocols and Support,  Next: Multimedia Services,  Prev: Structured Markup Processing Tools,  Up: The Python Standard Library

5.22 Internet Protocols and Support
===================================

The modules described in this chapter implement internet protocols and
support for related technology.  They are all implemented in Python.
Most of these modules require the presence of the system-dependent
module *note socket: cc, which is currently supported on most popular
platforms.  Here is an overview:

* Menu:

* webbrowser — Convenient web-browser controller::
* wsgiref — WSGI Utilities and Reference Implementation::
* urllib — URL handling modules::
* urllib.request — Extensible library for opening URLs: urllib request — Extensible library for opening URLs.
* urllib.response — Response classes used by urllib: urllib response — Response classes used by urllib.
* urllib.parse — Parse URLs into components: urllib parse — Parse URLs into components.
* urllib.error — Exception classes raised by urllib.request: urllib error — Exception classes raised by urllib request.
* urllib.robotparser — Parser for robots.txt: urllib robotparser — Parser for robots txt.
* http — HTTP modules::
* http.client — HTTP protocol client: http client — HTTP protocol client.
* ftplib — FTP protocol client::
* poplib — POP3 protocol client::
* imaplib — IMAP4 protocol client::
* smtplib — SMTP protocol client::
* uuid — UUID objects according to RFC 4122::
* socketserver — A framework for network servers::
* http.server — HTTP servers: http server — HTTP servers.
* http.cookies — HTTP state management: http cookies — HTTP state management.
* http.cookiejar — Cookie handling for HTTP clients: http cookiejar — Cookie handling for HTTP clients.
* xmlrpc — XMLRPC server and client modules::
* xmlrpc.client — XML-RPC client access: xmlrpc client — XML-RPC client access.
* xmlrpc.server — Basic XML-RPC servers: xmlrpc server — Basic XML-RPC servers.
* ipaddress — IPv4/IPv6 manipulation library::


File: python.info,  Node: webbrowser — Convenient web-browser controller,  Next: wsgiref — WSGI Utilities and Reference Implementation,  Up: Internet Protocols and Support

5.22.1 ‘webbrowser’ — Convenient web-browser controller
-------------------------------------------------------

'Source code:' Lib/webbrowser.py(1)

__________________________________________________________________

The ‘webbrowser’ module provides a high-level interface to allow
displaying web-based documents to users.  Under most circumstances,
simply calling the *note open(): 15a8. function from this module will do
the right thing.

Under Unix, graphical browsers are preferred under X11, but text-mode
browsers will be used if graphical browsers are not available or an X11
display isn’t available.  If text-mode browsers are used, the calling
process will block until the user exits the browser.

If the environment variable ‘BROWSER’ exists, it is interpreted as the
*note os.pathsep: 1eec.-separated list of browsers to try ahead of the
platform defaults.  When the value of a list part contains the string
‘%s’, then it is interpreted as a literal browser command line to be
used with the argument URL substituted for ‘%s’; if the part does not
contain ‘%s’, it is simply interpreted as the name of the browser to
launch.  (2)

For non-Unix platforms, or when a remote browser is available on Unix,
the controlling process will not wait for the user to finish with the
browser, but allow the remote browser to maintain its own windows on the
display.  If remote browsers are not available on Unix, the controlling
process will launch a new browser and wait.

On iOS, the ‘BROWSER’ environment variable, as well as any arguments
controlling autoraise, browser preference, and new tab/window creation
will be ignored.  Web pages will 'always' be opened in the user’s
preferred browser, in a new tab, with the browser being brought to the
foreground.  The use of the ‘webbrowser’ module on iOS requires the
*note ctypes: 2a. module.  If ‘ctypes’ isn’t available, calls to *note
open(): 15a8. will fail.

* Menu:

* Command-line interface: Command-line interface<4>.
* Browser controller objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/webbrowser.py

   (2) Executables named here without a full path will be searched in
the directories given in the ‘PATH’ environment variable.


File: python.info,  Node: Command-line interface<4>,  Next: Browser controller objects,  Up: webbrowser — Convenient web-browser controller

5.22.1.1 Command-line interface
...............................

The script ‘webbrowser’ can be used as a command-line interface for the
module.  It accepts a URL as the argument.  It accepts the following
optional parameters:

 -- Option: -n, --new-window

     Opens the URL in a new browser window, if possible.

 -- Option: -t, --new-tab

     Opens the URL in a new browser tab.

The options are, naturally, mutually exclusive.  Usage example:

     python -m webbrowser -t "https://www.python.org"

*note Availability: 1ef7.: not WASI, not Android.

The following exception is defined:

 -- Exception: webbrowser.Error

     Exception raised when a browser control error occurs.

The following functions are defined:

 -- Function: webbrowser.open (url, new=0, autoraise=True)

     Display 'url' using the default browser.  If 'new' is 0, the 'url'
     is opened in the same browser window if possible.  If 'new' is 1, a
     new browser window is opened if possible.  If 'new' is 2, a new
     browser page (“tab”) is opened if possible.  If 'autoraise' is
     ‘True’, the window is raised if possible (note that under many
     window managers this will occur regardless of the setting of this
     variable).

     Returns ‘True’ if a browser was successfully launched, ‘False’
     otherwise.

     Note that on some platforms, trying to open a filename using this
     function, may work and start the operating system’s associated
     program.  However, this is neither supported nor portable.

     Raises an *note auditing event: 1a15. ‘webbrowser.open’ with
     argument ‘url’.

 -- Function: webbrowser.open_new (url)

     Open 'url' in a new window of the default browser, if possible,
     otherwise, open 'url' in the only browser window.

     Returns ‘True’ if a browser was successfully launched, ‘False’
     otherwise.

 -- Function: webbrowser.open_new_tab (url)

     Open 'url' in a new page (“tab”) of the default browser, if
     possible, otherwise equivalent to *note open_new(): 3b97.

     Returns ‘True’ if a browser was successfully launched, ‘False’
     otherwise.

 -- Function: webbrowser.get (using=None)

     Return a controller object for the browser type 'using'.  If
     'using' is ‘None’, return a controller for a default browser
     appropriate to the caller’s environment.

 -- Function: webbrowser.register (name, constructor, instance=None, *,
          preferred=False)

     Register the browser type 'name'.  Once a browser type is
     registered, the *note get(): 3b99. function can return a controller
     for that browser type.  If 'instance' is not provided, or is
     ‘None’, 'constructor' will be called without parameters to create
     an instance when needed.  If 'instance' is provided, 'constructor'
     will never be called, and may be ‘None’.

     Setting 'preferred' to ‘True’ makes this browser a preferred result
     for a *note get(): 3b99. call with no argument.  Otherwise, this
     entry point is only useful if you plan to either set the ‘BROWSER’
     variable or call ‘get()’ with a nonempty argument matching the name
     of a handler you declare.

     Changed in version 3.7: 'preferred' keyword-only parameter was
     added.

A number of browser types are predefined.  This table gives the type
names that may be passed to the *note get(): 3b99. function and the
corresponding instantiations for the controller classes, all defined in
this module.

Type Name                    Class Name                                    Notes
                                                                           
---------------------------------------------------------------------------------------
                                                                           
‘'mozilla'’                  ‘Mozilla('mozilla')’
                             
                                                                           
‘'firefox'’                  ‘Mozilla('mozilla')’
                             
                                                                           
‘'epiphany'’                 ‘Epiphany('epiphany')’
                             
                                                                           
‘'kfmclient'’                ‘Konqueror()’                                 (1)
                                                                           
                                                                           
‘'konqueror'’                ‘Konqueror()’                                 (1)
                                                                           
                                                                           
‘'kfm'’                      ‘Konqueror()’                                 (1)
                                                                           
                                                                           
‘'opera'’                    ‘Opera()’
                             
                                                                           
‘'links'’                    ‘GenericBrowser('links')’
                             
                                                                           
‘'elinks'’                   ‘Elinks('elinks')’
                             
                                                                           
‘'lynx'’                     ‘GenericBrowser('lynx')’
                             
                                                                           
‘'w3m'’                      ‘GenericBrowser('w3m')’
                             
                                                                           
‘'windows-default'’          ‘WindowsDefault’                              (2)
                                                                           
                                                                           
‘'macosx'’                   ‘MacOSXOSAScript('default')’                  (3)
                                                                           
                                                                           
‘'safari'’                   ‘MacOSXOSAScript('safari')’                   (3)
                                                                           
                                                                           
‘'google-chrome'’            ‘Chrome('google-chrome')’
                             
                                                                           
‘'chrome'’                   ‘Chrome('chrome')’
                             
                                                                           
‘'chromium'’                 ‘Chromium('chromium')’
                             
                                                                           
‘'chromium-browser'’         ‘Chromium('chromium-browser')’
                             
                                                                           
‘'iosbrowser'’               ‘IOSBrowser’                                  (4)
                                                                           

Notes:

  1. “Konqueror” is the file manager for the KDE desktop environment for
     Unix, and only makes sense to use if KDE is running.  Some way of
     reliably detecting KDE would be nice; the ‘KDEDIR’ variable is not
     sufficient.  Note also that the name “kfm” is used even when using
     the ‘konqueror’ command with KDE 2 — the implementation selects the
     best strategy for running Konqueror.

  2. Only on Windows platforms.

  3. Only on macOS.

  4. Only on iOS.

Added in version 3.2: A new ‘MacOSXOSAScript’ class has been added and
is used on Mac instead of the previous ‘MacOSX’ class.  This adds
support for opening browsers not currently set as the OS default.

Added in version 3.3: Support for Chrome/Chromium has been added.

Changed in version 3.12: Support for several obsolete browsers has been
removed.  Removed browsers include Grail, Mosaic, Netscape, Galeon,
Skipstone, Iceape, and Firefox versions 35 and below.

Changed in version 3.13: Support for iOS has been added.

Here are some simple examples:

     url = 'https://docs.python.org/'

     # Open URL in a new tab, if a browser window is already open.
     webbrowser.open_new_tab(url)

     # Open URL in new window, raising the window if possible.
     webbrowser.open_new(url)


File: python.info,  Node: Browser controller objects,  Prev: Command-line interface<4>,  Up: webbrowser — Convenient web-browser controller

5.22.1.2 Browser controller objects
...................................

Browser controllers provide the *note name: 297. attribute, and the
following three methods which parallel module-level convenience
functions:

 -- Attribute: controller.name

     System-dependent name for the browser.

 -- Method: controller.open (url, new=0, autoraise=True)

     Display 'url' using the browser handled by this controller.  If
     'new' is 1, a new browser window is opened if possible.  If 'new'
     is 2, a new browser page (“tab”) is opened if possible.

 -- Method: controller.open_new (url)

     Open 'url' in a new window of the browser handled by this
     controller, if possible, otherwise, open 'url' in the only browser
     window.  Alias *note open_new(): 3b97.

 -- Method: controller.open_new_tab (url)

     Open 'url' in a new page (“tab”) of the browser handled by this
     controller, if possible, otherwise equivalent to *note open_new():
     3b97.


File: python.info,  Node: wsgiref — WSGI Utilities and Reference Implementation,  Next: urllib — URL handling modules,  Prev: webbrowser — Convenient web-browser controller,  Up: Internet Protocols and Support

5.22.2 ‘wsgiref’ — WSGI Utilities and Reference Implementation
--------------------------------------------------------------

'Source code:' Lib/wsgiref(1)

__________________________________________________________________

     Warning: ‘wsgiref’ is a reference implementation and is not
     recommended for production.  The module only implements basic
     security checks.

The Web Server Gateway Interface (WSGI) is a standard interface between
web server software and web applications written in Python.  Having a
standard interface makes it easy to use an application that supports
WSGI with a number of different web servers.

Only authors of web servers and programming frameworks need to know
every detail and corner case of the WSGI design.  You don’t need to
understand every detail of WSGI just to install a WSGI application or to
write a web application using an existing framework.

‘wsgiref’ is a reference implementation of the WSGI specification that
can be used to add WSGI support to a web server or framework.  It
provides utilities for manipulating WSGI environment variables and
response headers, base classes for implementing WSGI servers, a demo
HTTP server that serves WSGI applications, types for static type
checking, and a validation tool that checks WSGI servers and
applications for conformance to the WSGI specification ( PEP 3333(2)).

See wsgi.readthedocs.io(3) for more information about WSGI, and links to
tutorials and other resources.

* Menu:

* wsgiref.util – WSGI environment utilities: wsgiref util – WSGI environment utilities.
* wsgiref.headers – WSGI response header tools: wsgiref headers – WSGI response header tools.
* wsgiref.simple_server – a simple WSGI HTTP server: wsgiref simple_server – a simple WSGI HTTP server.
* wsgiref.validate — WSGI conformance checker: wsgiref validate — WSGI conformance checker.
* wsgiref.handlers – server/gateway base classes: wsgiref handlers – server/gateway base classes.
* wsgiref.types – WSGI types for static type checking: wsgiref types – WSGI types for static type checking.
* Examples: Examples<25>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/wsgiref

   (2) https://peps.python.org/pep-3333/

   (3) https://wsgi.readthedocs.io/


File: python.info,  Node: wsgiref util – WSGI environment utilities,  Next: wsgiref headers – WSGI response header tools,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.1 ‘wsgiref.util’ – WSGI environment utilities
....................................................

This module provides a variety of utility functions for working with
WSGI environments.  A WSGI environment is a dictionary containing HTTP
request variables as described in PEP 3333(1).  All of the functions
taking an 'environ' parameter expect a WSGI-compliant dictionary to be
supplied; please see PEP 3333(2) for a detailed specification and *note
WSGIEnvironment: 3ba4. for a type alias that can be used in type
annotations.

 -- Function: wsgiref.util.guess_scheme (environ)

     Return a guess for whether ‘wsgi.url_scheme’ should be “http” or
     “https”, by checking for a ‘HTTPS’ environment variable in the
     'environ' dictionary.  The return value is a string.

     This function is useful when creating a gateway that wraps CGI or a
     CGI-like protocol such as FastCGI. Typically, servers providing
     such protocols will include a ‘HTTPS’ variable with a value of “1”,
     “yes”, or “on” when a request is received via SSL. So, this
     function returns “https” if such a value is found, and “http”
     otherwise.

 -- Function: wsgiref.util.request_uri (environ, include_query=True)

     Return the full request URI, optionally including the query string,
     using the algorithm found in the “URL Reconstruction” section of
     PEP 3333(3).  If 'include_query' is false, the query string is not
     included in the resulting URI.

 -- Function: wsgiref.util.application_uri (environ)

     Similar to *note request_uri(): 3ba6, except that the ‘PATH_INFO’
     and ‘QUERY_STRING’ variables are ignored.  The result is the base
     URI of the application object addressed by the request.

 -- Function: wsgiref.util.shift_path_info (environ)

     Shift a single name from ‘PATH_INFO’ to ‘SCRIPT_NAME’ and return
     the name.  The 'environ' dictionary is 'modified' in-place; use a
     copy if you need to keep the original ‘PATH_INFO’ or ‘SCRIPT_NAME’
     intact.

     If there are no remaining path segments in ‘PATH_INFO’, ‘None’ is
     returned.

     Typically, this routine is used to process each portion of a
     request URI path, for example to treat the path as a series of
     dictionary keys.  This routine modifies the passed-in environment
     to make it suitable for invoking another WSGI application that is
     located at the target URI. For example, if there is a WSGI
     application at ‘/foo’, and the request URI path is ‘/foo/bar/baz’,
     and the WSGI application at ‘/foo’ calls ‘shift_path_info()’, it
     will receive the string “bar”, and the environment will be updated
     to be suitable for passing to a WSGI application at ‘/foo/bar’.
     That is, ‘SCRIPT_NAME’ will change from ‘/foo’ to ‘/foo/bar’, and
     ‘PATH_INFO’ will change from ‘/bar/baz’ to ‘/baz’.

     When ‘PATH_INFO’ is just a “/”, this routine returns an empty
     string and appends a trailing slash to ‘SCRIPT_NAME’, even though
     empty path segments are normally ignored, and ‘SCRIPT_NAME’ doesn’t
     normally end in a slash.  This is intentional behavior, to ensure
     that an application can tell the difference between URIs ending in
     ‘/x’ from ones ending in ‘/x/’ when using this routine to do object
     traversal.

 -- Function: wsgiref.util.setup_testing_defaults (environ)

     Update 'environ' with trivial defaults for testing purposes.

     This routine adds various parameters required for WSGI, including
     ‘HTTP_HOST’, ‘SERVER_NAME’, ‘SERVER_PORT’, ‘REQUEST_METHOD’,
     ‘SCRIPT_NAME’, ‘PATH_INFO’, and all of the PEP 3333(4)-defined
     ‘wsgi.*’ variables.  It only supplies default values, and does not
     replace any existing settings for these variables.

     This routine is intended to make it easier for unit tests of WSGI
     servers and applications to set up dummy environments.  It should
     NOT be used by actual WSGI servers or applications, since the data
     is fake!

     Example usage (see also *note demo_app(): 3baa. for another
     example):

          from wsgiref.util import setup_testing_defaults
          from wsgiref.simple_server import make_server

          # A relatively simple WSGI application. It's going to print out the
          # environment dictionary after being updated by setup_testing_defaults
          def simple_app(environ, start_response):
              setup_testing_defaults(environ)

              status = '200 OK'
              headers = [('Content-type', 'text/plain; charset=utf-8')]

              start_response(status, headers)

              ret = [("%s: %s\n" % (key, value)).encode("utf-8")
                     for key, value in environ.items()]
              return ret

          with make_server('', 8000, simple_app) as httpd:
              print("Serving on port 8000...")
              httpd.serve_forever()

In addition to the environment functions above, the ‘wsgiref.util’
module also provides these miscellaneous utilities:

 -- Function: wsgiref.util.is_hop_by_hop (header_name)

     Return ‘True’ if ‘header_name’ is an HTTP/1.1 “Hop-by-Hop” header,
     as defined by RFC 2616(5).

 -- Class: wsgiref.util.FileWrapper (filelike, blksize=8192)

     A concrete implementation of the *note wsgiref.types.FileWrapper:
     3bab. protocol used to convert a file-like object to an *note
     iterator: 1ac.  The resulting objects are *note iterable: 126d.s.
     As the object is iterated over, the optional 'blksize' parameter
     will be repeatedly passed to the 'filelike' object’s ‘read()’
     method to obtain bytestrings to yield.  When ‘read()’ returns an
     empty bytestring, iteration is ended and is not resumable.

     If 'filelike' has a ‘close()’ method, the returned object will also
     have a ‘close()’ method, and it will invoke the 'filelike' object’s
     ‘close()’ method when called.

     Example usage:

          from io import StringIO
          from wsgiref.util import FileWrapper

          # We're using a StringIO-buffer for as the file-like object
          filelike = StringIO("This is an example file-like object"*10)
          wrapper = FileWrapper(filelike, blksize=5)

          for chunk in wrapper:
              print(chunk)

     Changed in version 3.11: Support for *note __getitem__(): 283.
     method has been removed.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/

   (2) https://peps.python.org/pep-3333/

   (3) https://peps.python.org/pep-3333/

   (4) https://peps.python.org/pep-3333/

   (5) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: wsgiref headers – WSGI response header tools,  Next: wsgiref simple_server – a simple WSGI HTTP server,  Prev: wsgiref util – WSGI environment utilities,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.2 ‘wsgiref.headers’ – WSGI response header tools
.......................................................

This module provides a single class, *note Headers: ecc, for convenient
manipulation of WSGI response headers using a mapping-like interface.

 -- Class: wsgiref.headers.Headers ([headers])

     Create a mapping-like object wrapping 'headers', which must be a
     list of header name/value tuples as described in PEP 3333(1).  The
     default value of 'headers' is an empty list.

     ‘Headers’ objects support typical mapping operations including
     *note __getitem__(): 283, *note get(): 1dea, *note __setitem__():
     1313, *note setdefault(): 10b7, *note __delitem__(): 1314. and
     *note __contains__(): 1406.  For each of these methods, the key is
     the header name (treated case-insensitively), and the value is the
     first value associated with that header name.  Setting a header
     deletes any existing values for that header, then adds a new value
     at the end of the wrapped header list.  Headers’ existing order is
     generally maintained, with new headers added to the end of the
     wrapped list.

     Unlike a dictionary, ‘Headers’ objects do not raise an error when
     you try to get or delete a key that isn’t in the wrapped header
     list.  Getting a nonexistent header just returns ‘None’, and
     deleting a nonexistent header does nothing.

     ‘Headers’ objects also support ‘keys()’, ‘values()’, and ‘items()’
     methods.  The lists returned by ‘keys()’ and ‘items()’ can include
     the same key more than once if there is a multi-valued header.  The
     ‘len()’ of a ‘Headers’ object is the same as the length of its
     ‘items()’, which is the same as the length of the wrapped header
     list.  In fact, the ‘items()’ method just returns a copy of the
     wrapped header list.

     Calling ‘bytes()’ on a ‘Headers’ object returns a formatted
     bytestring suitable for transmission as HTTP response headers.
     Each header is placed on a line with its value, separated by a
     colon and a space.  Each line is terminated by a carriage return
     and line feed, and the bytestring is terminated with a blank line.

     In addition to their mapping interface and formatting features,
     ‘Headers’ objects also have the following methods for querying and
     adding multi-valued headers, and for adding headers with MIME
     parameters:

      -- Method: get_all (name)

          Return a list of all the values for the named header.

          The returned list will be sorted in the order they appeared in
          the original header list or were added to this instance, and
          may contain duplicates.  Any fields deleted and re-inserted
          are always appended to the header list.  If no fields exist
          with the given name, returns an empty list.

      -- Method: add_header (name, value, **_params)

          Add a (possibly multi-valued) header, with optional MIME
          parameters specified via keyword arguments.

          'name' is the header field to add.  Keyword arguments can be
          used to set MIME parameters for the header field.  Each
          parameter must be a string or ‘None’.  Underscores in
          parameter names are converted to dashes, since dashes are
          illegal in Python identifiers, but many MIME parameter names
          include dashes.  If the parameter value is a string, it is
          added to the header value parameters in the form
          ‘name="value"’.  If it is ‘None’, only the parameter name is
          added.  (This is used for MIME parameters without a value.)
          Example usage:

               h.add_header('content-disposition', 'attachment', filename='bud.gif')

          The above will add a header that looks like this:

               Content-Disposition: attachment; filename="bud.gif"

     Changed in version 3.5: 'headers' parameter is optional.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/


File: python.info,  Node: wsgiref simple_server – a simple WSGI HTTP server,  Next: wsgiref validate — WSGI conformance checker,  Prev: wsgiref headers – WSGI response header tools,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.3 ‘wsgiref.simple_server’ – a simple WSGI HTTP server
............................................................

This module implements a simple HTTP server (based on *note http.server:
72.) that serves WSGI applications.  Each server instance serves a
single WSGI application on a given host and port.  If you want to serve
multiple applications on a single host and port, you should create a
WSGI application that parses ‘PATH_INFO’ to select which application to
invoke for each request.  (E.g., using the ‘shift_path_info()’ function
from *note wsgiref.util: 11d.)

 -- Function: wsgiref.simple_server.make_server (host, port, app,
          server_class=WSGIServer, handler_class=WSGIRequestHandler)

     Create a new WSGI server listening on 'host' and 'port', accepting
     connections for 'app'.  The return value is an instance of the
     supplied 'server_class', and will process requests using the
     specified 'handler_class'.  'app' must be a WSGI application
     object, as defined by PEP 3333(1).

     Example usage:

          from wsgiref.simple_server import make_server, demo_app

          with make_server('', 8000, demo_app) as httpd:
              print("Serving HTTP on port 8000...")

              # Respond to requests until process is killed
              httpd.serve_forever()

              # Alternative: serve one request, then exit
              httpd.handle_request()

 -- Function: wsgiref.simple_server.demo_app (environ, start_response)

     This function is a small but complete WSGI application that returns
     a text page containing the message “Hello world!” and a list of the
     key/value pairs provided in the 'environ' parameter.  It’s useful
     for verifying that a WSGI server (such as ‘wsgiref.simple_server’)
     is able to run a simple WSGI application correctly.

     The 'start_response' callable should follow the *note
     StartResponse: 3bb1. protocol.

 -- Class: wsgiref.simple_server.WSGIServer (server_address,
          RequestHandlerClass)

     Create a ‘WSGIServer’ instance.  'server_address' should be a
     ‘(host,port)’ tuple, and 'RequestHandlerClass' should be the
     subclass of *note http.server.BaseHTTPRequestHandler: 110f. that
     will be used to process requests.

     You do not normally need to call this constructor, as the *note
     make_server(): 3bb0. function can handle all the details for you.

     ‘WSGIServer’ is a subclass of *note http.server.HTTPServer: 3bb3,
     so all of its methods (such as ‘serve_forever()’ and
     ‘handle_request()’) are available.  ‘WSGIServer’ also provides
     these WSGI-specific methods:

      -- Method: set_app (application)

          Sets the callable 'application' as the WSGI application that
          will receive requests.

      -- Method: get_app ()

          Returns the currently set application callable.

     Normally, however, you do not need to use these additional methods,
     as *note set_app(): 3bb4. is normally called by *note
     make_server(): 3bb0, and the *note get_app(): 3bb5. exists mainly
     for the benefit of request handler instances.

 -- Class: wsgiref.simple_server.WSGIRequestHandler (request,
          client_address, server)

     Create an HTTP handler for the given 'request' (i.e.  a socket),
     'client_address' (a ‘(host,port)’ tuple), and 'server' (*note
     WSGIServer: 3bb2. instance).

     You do not need to create instances of this class directly; they
     are automatically created as needed by *note WSGIServer: 3bb2.
     objects.  You can, however, subclass this class and supply it as a
     'handler_class' to the *note make_server(): 3bb0. function.  Some
     possibly relevant methods for overriding in subclasses:

      -- Method: get_environ ()

          Return a *note WSGIEnvironment: 3ba4. dictionary for a
          request.  The default implementation copies the contents of
          the *note WSGIServer: 3bb2. object’s ‘base_environ’ dictionary
          attribute and then adds various headers derived from the HTTP
          request.  Each call to this method should return a new
          dictionary containing all of the relevant CGI environment
          variables as specified in PEP 3333(2).

      -- Method: get_stderr ()

          Return the object that should be used as the ‘wsgi.errors’
          stream.  The default implementation just returns ‘sys.stderr’.

      -- Method: handle ()

          Process the HTTP request.  The default implementation creates
          a handler instance using a *note wsgiref.handlers: 119. class
          to implement the actual WSGI application interface.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/

   (2) https://peps.python.org/pep-3333/


File: python.info,  Node: wsgiref validate — WSGI conformance checker,  Next: wsgiref handlers – server/gateway base classes,  Prev: wsgiref simple_server – a simple WSGI HTTP server,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.4 ‘wsgiref.validate’ — WSGI conformance checker
......................................................

When creating new WSGI application objects, frameworks, servers, or
middleware, it can be useful to validate the new code’s conformance
using ‘wsgiref.validate’.  This module provides a function that creates
WSGI application objects that validate communications between a WSGI
server or gateway and a WSGI application object, to check both sides for
protocol conformance.

Note that this utility does not guarantee complete PEP 3333(1)
compliance; an absence of errors from this module does not necessarily
mean that errors do not exist.  However, if this module does produce an
error, then it is virtually certain that either the server or
application is not 100% compliant.

This module is based on the ‘paste.lint’ module from Ian Bicking’s
“Python Paste” library.

 -- Function: wsgiref.validate.validator (application)

     Wrap 'application' and return a new WSGI application object.  The
     returned application will forward all requests to the original
     'application', and will check that both the 'application' and the
     server invoking it are conforming to the WSGI specification and to
     RFC 2616(2).

     Any detected nonconformance results in an *note AssertionError:
     6ac. being raised; note, however, that how these errors are handled
     is server-dependent.  For example, *note wsgiref.simple_server:
     11b. and other servers based on *note wsgiref.handlers: 119. (that
     don’t override the error handling methods to do something else)
     will simply output a message that an error has occurred, and dump
     the traceback to ‘sys.stderr’ or some other error stream.

     This wrapper may also generate output using the *note warnings:
     112. module to indicate behaviors that are questionable but which
     may not actually be prohibited by PEP 3333(3).  Unless they are
     suppressed using Python command-line options or the ‘warnings’ API,
     any such warnings will be written to ‘sys.stderr’ ('not'
     ‘wsgi.errors’, unless they happen to be the same object).

     Example usage:

          from wsgiref.validate import validator
          from wsgiref.simple_server import make_server

          # Our callable object which is intentionally not compliant to the
          # standard, so the validator is going to break
          def simple_app(environ, start_response):
              status = '200 OK'  # HTTP Status
              headers = [('Content-type', 'text/plain')]  # HTTP Headers
              start_response(status, headers)

              # This is going to break because we need to return a list, and
              # the validator is going to inform us
              return b"Hello World"

          # This is the application wrapped in a validator
          validator_app = validator(simple_app)

          with make_server('', 8000, validator_app) as httpd:
              print("Listening on port 8000....")
              httpd.serve_forever()

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/

   (2) https://datatracker.ietf.org/doc/html/rfc2616.html

   (3) https://peps.python.org/pep-3333/


File: python.info,  Node: wsgiref handlers – server/gateway base classes,  Next: wsgiref types – WSGI types for static type checking,  Prev: wsgiref validate — WSGI conformance checker,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.5 ‘wsgiref.handlers’ – server/gateway base classes
.........................................................

This module provides base handler classes for implementing WSGI servers
and gateways.  These base classes handle most of the work of
communicating with a WSGI application, as long as they are given a
CGI-like environment, along with input, output, and error streams.

 -- Class: wsgiref.handlers.CGIHandler

     CGI-based invocation via ‘sys.stdin’, ‘sys.stdout’, ‘sys.stderr’
     and ‘os.environ’.  This is useful when you have a WSGI application
     and want to run it as a CGI script.  Simply invoke
     ‘CGIHandler().run(app)’, where ‘app’ is the WSGI application object
     you wish to invoke.

     This class is a subclass of *note BaseCGIHandler: 3bbe. that sets
     ‘wsgi.run_once’ to true, ‘wsgi.multithread’ to false, and
     ‘wsgi.multiprocess’ to true, and always uses *note sys: d9. and
     *note os: a1. to obtain the necessary CGI streams and environment.

 -- Class: wsgiref.handlers.IISCGIHandler

     A specialized alternative to *note CGIHandler: 3bbd, for use when
     deploying on Microsoft’s IIS web server, without having set the
     config allowPathInfo option (IIS>=7) or metabase
     allowPathInfoForScriptMappings (IIS<7).

     By default, IIS gives a ‘PATH_INFO’ that duplicates the
     ‘SCRIPT_NAME’ at the front, causing problems for WSGI applications
     that wish to implement routing.  This handler strips any such
     duplicated path.

     IIS can be configured to pass the correct ‘PATH_INFO’, but this
     causes another bug where ‘PATH_TRANSLATED’ is wrong.  Luckily this
     variable is rarely used and is not guaranteed by WSGI. On IIS<7,
     though, the setting can only be made on a vhost level, affecting
     all other script mappings, many of which break when exposed to the
     ‘PATH_TRANSLATED’ bug.  For this reason IIS<7 is almost never
     deployed with the fix (Even IIS7 rarely uses it because there is
     still no UI for it.).

     There is no way for CGI code to tell whether the option was set, so
     a separate handler class is provided.  It is used in the same way
     as *note CGIHandler: 3bbd, i.e., by calling
     ‘IISCGIHandler().run(app)’, where ‘app’ is the WSGI application
     object you wish to invoke.

     Added in version 3.2.

 -- Class: wsgiref.handlers.BaseCGIHandler (stdin, stdout, stderr,
          environ, multithread=True, multiprocess=False)

     Similar to *note CGIHandler: 3bbd, but instead of using the *note
     sys: d9. and *note os: a1. modules, the CGI environment and I/O
     streams are specified explicitly.  The 'multithread' and
     'multiprocess' values are used to set the ‘wsgi.multithread’ and
     ‘wsgi.multiprocess’ flags for any applications run by the handler
     instance.

     This class is a subclass of *note SimpleHandler: 3bc0. intended for
     use with software other than HTTP “origin servers”.  If you are
     writing a gateway protocol implementation (such as CGI, FastCGI,
     SCGI, etc.)  that uses a ‘Status:’ header to send an HTTP status,
     you probably want to subclass this instead of ‘SimpleHandler’.

 -- Class: wsgiref.handlers.SimpleHandler (stdin, stdout, stderr,
          environ, multithread=True, multiprocess=False)

     Similar to *note BaseCGIHandler: 3bbe, but designed for use with
     HTTP origin servers.  If you are writing an HTTP server
     implementation, you will probably want to subclass this instead of
     ‘BaseCGIHandler’.

     This class is a subclass of *note BaseHandler: 1b80.  It overrides
     the ‘__init__()’, *note get_stdin(): 3bc1, *note get_stderr():
     3bc2, *note add_cgi_vars(): 3bc3, *note _write(): 3bc4, and *note
     _flush(): 3bc5. methods to support explicitly setting the
     environment and streams via the constructor.  The supplied
     environment and streams are stored in the ‘stdin’, ‘stdout’,
     ‘stderr’, and ‘environ’ attributes.

     The *note write(): d02. method of 'stdout' should write each chunk
     in full, like *note io.BufferedIOBase: 697.

 -- Class: wsgiref.handlers.BaseHandler

     This is an abstract base class for running WSGI applications.  Each
     instance will handle a single HTTP request, although in principle
     you could create a subclass that was reusable for multiple
     requests.

     ‘BaseHandler’ instances have only one method intended for external
     use:

      -- Method: run (app)

          Run the specified WSGI application, 'app'.

     All of the other ‘BaseHandler’ methods are invoked by this method
     in the process of running the application, and thus exist primarily
     to allow customizing the process.

     The following methods MUST be overridden in a subclass:

      -- Method: _write (data)

          Buffer the bytes 'data' for transmission to the client.  It’s
          okay if this method actually transmits the data; ‘BaseHandler’
          just separates write and flush operations for greater
          efficiency when the underlying system actually has such a
          distinction.

      -- Method: _flush ()

          Force buffered data to be transmitted to the client.  It’s
          okay if this method is a no-op (i.e., if *note _write(): 3bc4.
          actually sends the data).

      -- Method: get_stdin ()

          Return an object compatible with *note InputStream: 3bc7.
          suitable for use as the ‘wsgi.input’ of the request currently
          being processed.

      -- Method: get_stderr ()

          Return an object compatible with *note ErrorStream: 3bc8.
          suitable for use as the ‘wsgi.errors’ of the request currently
          being processed.

      -- Method: add_cgi_vars ()

          Insert CGI variables for the current request into the
          ‘environ’ attribute.

     Here are some other methods and attributes you may wish to
     override.  This list is only a summary, however, and does not
     include every method that can be overridden.  You should consult
     the docstrings and source code for additional information before
     attempting to create a customized ‘BaseHandler’ subclass.

     Attributes and methods for customizing the WSGI environment:

      -- Attribute: wsgi_multithread

          The value to be used for the ‘wsgi.multithread’ environment
          variable.  It defaults to true in ‘BaseHandler’, but may have
          a different default (or be set by the constructor) in the
          other subclasses.

      -- Attribute: wsgi_multiprocess

          The value to be used for the ‘wsgi.multiprocess’ environment
          variable.  It defaults to true in ‘BaseHandler’, but may have
          a different default (or be set by the constructor) in the
          other subclasses.

      -- Attribute: wsgi_run_once

          The value to be used for the ‘wsgi.run_once’ environment
          variable.  It defaults to false in ‘BaseHandler’, but *note
          CGIHandler: 3bbd. sets it to true by default.

      -- Attribute: os_environ

          The default environment variables to be included in every
          request’s WSGI environment.  By default, this is a copy of
          ‘os.environ’ at the time that ‘wsgiref.handlers’ was imported,
          but subclasses can either create their own at the class or
          instance level.  Note that the dictionary should be considered
          read-only, since the default value is shared between multiple
          classes and instances.

      -- Attribute: server_software

          If the *note origin_server: 3bce. attribute is set, this
          attribute’s value is used to set the default ‘SERVER_SOFTWARE’
          WSGI environment variable, and also to set a default ‘Server:’
          header in HTTP responses.  It is ignored for handlers (such as
          *note BaseCGIHandler: 3bbe. and *note CGIHandler: 3bbd.) that
          are not HTTP origin servers.

          Changed in version 3.3: The term “Python” is replaced with
          implementation specific term like “CPython”, “Jython” etc.

      -- Method: get_scheme ()

          Return the URL scheme being used for the current request.  The
          default implementation uses the ‘guess_scheme()’ function from
          *note wsgiref.util: 11d. to guess whether the scheme should be
          “http” or “https”, based on the current request’s ‘environ’
          variables.

      -- Method: setup_environ ()

          Set the ‘environ’ attribute to a fully populated WSGI
          environment.  The default implementation uses all of the above
          methods and attributes, plus the *note get_stdin(): 3bc1,
          *note get_stderr(): 3bc2, and *note add_cgi_vars(): 3bc3.
          methods and the *note wsgi_file_wrapper: 3bd1. attribute.  It
          also inserts a ‘SERVER_SOFTWARE’ key if not present, as long
          as the *note origin_server: 3bce. attribute is a true value
          and the *note server_software: 3bcd. attribute is set.

     Methods and attributes for customizing exception handling:

      -- Method: log_exception (exc_info)

          Log the 'exc_info' tuple in the server log.  'exc_info' is a
          ‘(type, value, traceback)’ tuple.  The default implementation
          simply writes the traceback to the request’s ‘wsgi.errors’
          stream and flushes it.  Subclasses can override this method to
          change the format or retarget the output, mail the traceback
          to an administrator, or whatever other action may be deemed
          suitable.

      -- Attribute: traceback_limit

          The maximum number of frames to include in tracebacks output
          by the default *note log_exception(): 3bd2. method.  If
          ‘None’, all frames are included.

      -- Method: error_output (environ, start_response)

          This method is a WSGI application to generate an error page
          for the user.  It is only invoked if an error occurs before
          headers are sent to the client.

          This method can access the current error using
          ‘sys.exception()’, and should pass that information to
          'start_response' when calling it (as described in the “Error
          Handling” section of PEP 3333(1)).  In particular, the
          'start_response' callable should follow the *note
          StartResponse: 3bb1. protocol.

          The default implementation just uses the *note error_status:
          3bd5, *note error_headers: 3bd6, and *note error_body: 3bd7.
          attributes to generate an output page.  Subclasses can
          override this to produce more dynamic error output.

          Note, however, that it’s not recommended from a security
          perspective to spit out diagnostics to any old user; ideally,
          you should have to do something special to enable diagnostic
          output, which is why the default implementation doesn’t
          include any.

      -- Attribute: error_status

          The HTTP status used for error responses.  This should be a
          status string as defined in PEP 3333(2); it defaults to a 500
          code and message.

      -- Attribute: error_headers

          The HTTP headers used for error responses.  This should be a
          list of WSGI response headers (‘(name, value)’ tuples), as
          described in PEP 3333(3).  The default list just sets the
          content type to ‘text/plain’.

      -- Attribute: error_body

          The error response body.  This should be an HTTP response body
          bytestring.  It defaults to the plain text, “A server error
          occurred.  Please contact the administrator.”

     Methods and attributes for PEP 3333(4)’s “Optional
     Platform-Specific File Handling” feature:

      -- Attribute: wsgi_file_wrapper

          A ‘wsgi.file_wrapper’ factory, compatible with *note
          wsgiref.types.FileWrapper: 3bab, or ‘None’.  The default value
          of this attribute is the *note wsgiref.util.FileWrapper: 739.
          class.

      -- Method: sendfile ()

          Override to implement platform-specific file transmission.
          This method is called only if the application’s return value
          is an instance of the class specified by the *note
          wsgi_file_wrapper: 3bd1. attribute.  It should return a true
          value if it was able to successfully transmit the file, so
          that the default transmission code will not be executed.  The
          default implementation of this method just returns a false
          value.

     Miscellaneous methods and attributes:

      -- Attribute: origin_server

          This attribute should be set to a true value if the handler’s
          *note _write(): 3bc4. and *note _flush(): 3bc5. are being used
          to communicate directly to the client, rather than via a
          CGI-like gateway protocol that wants the HTTP status in a
          special ‘Status:’ header.

          This attribute’s default value is true in ‘BaseHandler’, but
          false in *note BaseCGIHandler: 3bbe. and *note CGIHandler:
          3bbd.

      -- Attribute: http_version

          If *note origin_server: 3bce. is true, this string attribute
          is used to set the HTTP version of the response set to the
          client.  It defaults to ‘"1.0"’.

 -- Function: wsgiref.handlers.read_environ ()

     Transcode CGI variables from ‘os.environ’ to PEP 3333(5) “bytes in
     unicode” strings, returning a new dictionary.  This function is
     used by *note CGIHandler: 3bbd. and *note IISCGIHandler: 3bbf. in
     place of directly using ‘os.environ’, which is not necessarily
     WSGI-compliant on all platforms and web servers using Python 3 –
     specifically, ones where the OS’s actual environment is Unicode
     (i.e.  Windows), or ones where the environment is bytes, but the
     system encoding used by Python to decode it is anything other than
     ISO-8859-1 (e.g.  Unix systems using UTF-8).

     If you are implementing a CGI-based handler of your own, you
     probably want to use this routine instead of just copying values
     out of ‘os.environ’ directly.

     Added in version 3.2.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/

   (2) https://peps.python.org/pep-3333/

   (3) https://peps.python.org/pep-3333/

   (4) https://peps.python.org/pep-3333/

   (5) https://peps.python.org/pep-3333/


File: python.info,  Node: wsgiref types – WSGI types for static type checking,  Next: Examples<25>,  Prev: wsgiref handlers – server/gateway base classes,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.6 ‘wsgiref.types’ – WSGI types for static type checking
..............................................................

This module provides various types for static type checking as described
in PEP 3333(1).

Added in version 3.11.

 -- Class: wsgiref.types.StartResponse

     A *note typing.Protocol: 264. describing start_response()(2)
     callables ( PEP 3333(3)).

 -- Data: wsgiref.types.WSGIEnvironment

     A type alias describing a WSGI environment dictionary.

 -- Data: wsgiref.types.WSGIApplication

     A type alias describing a WSGI application callable.

 -- Class: wsgiref.types.InputStream

     A *note typing.Protocol: 264. describing a WSGI Input Stream(4).

 -- Class: wsgiref.types.ErrorStream

     A *note typing.Protocol: 264. describing a WSGI Error Stream(5).

 -- Class: wsgiref.types.FileWrapper

     A *note typing.Protocol: 264. describing a file wrapper(6).  See
     *note wsgiref.util.FileWrapper: 739. for a concrete implementation
     of this protocol.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3333/

   (2) https://peps.python.org/pep-3333/#the-start-response-callable

   (3) https://peps.python.org/pep-3333/

   (4) https://peps.python.org/pep-3333/#input-and-error-streams

   (5) https://peps.python.org/pep-3333/#input-and-error-streams

   (6) 
https://peps.python.org/pep-3333/#optional-platform-specific-file-handling


File: python.info,  Node: Examples<25>,  Prev: wsgiref types – WSGI types for static type checking,  Up: wsgiref — WSGI Utilities and Reference Implementation

5.22.2.7 Examples
.................

This is a working “Hello World” WSGI application, where the
'start_response' callable should follow the *note StartResponse: 3bb1.
protocol:

     """
     Every WSGI application must have an application object - a callable
     object that accepts two arguments. For that purpose, we're going to
     use a function (note that you're not limited to a function, you can
     use a class for example). The first argument passed to the function
     is a dictionary containing CGI-style environment variables and the
     second variable is the callable object.
     """
     from wsgiref.simple_server import make_server


     def hello_world_app(environ, start_response):
         status = "200 OK"  # HTTP Status
         headers = [("Content-type", "text/plain; charset=utf-8")]  # HTTP Headers
         start_response(status, headers)

         # The returned object is going to be printed
         return [b"Hello World"]

     with make_server("", 8000, hello_world_app) as httpd:
         print("Serving on port 8000...")

         # Serve until process is killed
         httpd.serve_forever()

Example of a WSGI application serving the current directory, accept
optional directory and port number (default: 8000) on the command line:

     """
     Small wsgiref based web server. Takes a path to serve from and an
     optional port number (defaults to 8000), then tries to serve files.
     MIME types are guessed from the file names, 404 errors are raised
     if the file is not found.
     """
     import mimetypes
     import os
     import sys
     from wsgiref import simple_server, util


     def app(environ, respond):
         # Get the file name and MIME type
         fn = os.path.join(path, environ["PATH_INFO"][1:])
         if "." not in fn.split(os.path.sep)[-1]:
             fn = os.path.join(fn, "index.html")
         mime_type = mimetypes.guess_file_type(fn)[0]

         # Return 200 OK if file exists, otherwise 404 Not Found
         if os.path.exists(fn):
             respond("200 OK", [("Content-Type", mime_type)])
             return util.FileWrapper(open(fn, "rb"))
         else:
             respond("404 Not Found", [("Content-Type", "text/plain")])
             return [b"not found"]


     if __name__ == "__main__":
         # Get the path and port from command-line arguments
         path = sys.argv[1] if len(sys.argv) > 1 else os.getcwd()
         port = int(sys.argv[2]) if len(sys.argv) > 2 else 8000

         # Make and start the server until control-c
         httpd = simple_server.make_server("", port, app)
         print(f"Serving {path} on port {port}, control-C to stop")
         try:
             httpd.serve_forever()
         except KeyboardInterrupt:
             print("Shutting down.")
             httpd.server_close()


File: python.info,  Node: urllib — URL handling modules,  Next: urllib request — Extensible library for opening URLs,  Prev: wsgiref — WSGI Utilities and Reference Implementation,  Up: Internet Protocols and Support

5.22.3 ‘urllib’ — URL handling modules
--------------------------------------

'Source code:' Lib/urllib/(1)

__________________________________________________________________

‘urllib’ is a package that collects several modules for working with
URLs:

   * *note urllib.request: 10b. for opening and reading URLs

   * *note urllib.error: 109. containing the exceptions raised by *note
     urllib.request: 10b.

   * *note urllib.parse: 10a. for parsing URLs

   * *note urllib.robotparser: 10d. for parsing ‘robots.txt’ files

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/urllib/


File: python.info,  Node: urllib request — Extensible library for opening URLs,  Next: urllib response — Response classes used by urllib,  Prev: urllib — URL handling modules,  Up: Internet Protocols and Support

5.22.4 ‘urllib.request’ — Extensible library for opening URLs
-------------------------------------------------------------

'Source code:' Lib/urllib/request.py(1)

__________________________________________________________________

The ‘urllib.request’ module defines functions and classes which help in
opening URLs (mostly HTTP) in a complex world — basic and digest
authentication, redirections, cookies and more.

See also
........

The Requests package(2) is recommended for a higher-level HTTP client
interface.

     Warning: On macOS it is unsafe to use this module in programs using
     *note os.fork(): 197. because the *note getproxies(): 3be3.
     implementation for macOS uses a higher-level system API. Set the
     environment variable ‘no_proxy’ to ‘*’ to avoid this problem (e.g.
     ‘os.environ["no_proxy"] = "*"’).

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The ‘urllib.request’ module defines the following functions:

 -- Function: urllib.request.urlopen (url, data=None[, timeout], *,
          context=None)

     Open 'url', which can be either a string containing a valid,
     properly encoded URL, or a *note Request: 1013. object.

     'data' must be an object specifying additional data to be sent to
     the server, or ‘None’ if no such data is needed.  See *note
     Request: 1013. for details.

     urllib.request module uses HTTP/1.1 and includes ‘Connection:close’
     header in its HTTP requests.

     The optional 'timeout' parameter specifies a timeout in seconds for
     blocking operations like the connection attempt (if not specified,
     the global default timeout setting will be used).  This actually
     only works for HTTP, HTTPS and FTP connections.

     If 'context' is specified, it must be a *note ssl.SSLContext: 294.
     instance describing the various SSL options.  See *note
     HTTPSConnection: b5a. for more details.

     This function always returns an object which can work as a *note
     context manager: 5d7. and has the properties 'url', 'headers', and
     'status'.  See *note urllib.response.addinfourl: 3be4. for more
     detail on these properties.

     For HTTP and HTTPS URLs, this function returns a *note
     http.client.HTTPResponse: 1112. object slightly modified.  In
     addition to the three new methods above, the msg attribute contains
     the same information as the *note reason: 3be5. attribute — the
     reason phrase returned by server — instead of the response headers
     as it is specified in the documentation for ‘HTTPResponse’.

     For FTP, file, and data URLs and requests explicitly handled by
     legacy *note URLopener: 30e. and *note FancyURLopener: 30f.
     classes, this function returns a *note urllib.response.addinfourl:
     3be4. object.

     Raises *note URLError: 3be6. on protocol errors.

     Note that ‘None’ may be returned if no handler handles the request
     (though the default installed global *note OpenerDirector: 3be7.
     uses *note UnknownHandler: 3be8. to ensure this never happens).

     In addition, if proxy settings are detected (for example, when a
     ‘*_proxy’ environment variable like ‘http_proxy’ is set), *note
     ProxyHandler: 1b60. is default installed and makes sure the
     requests are handled through the proxy.

     The legacy ‘urllib.urlopen’ function from Python 2.6 and earlier
     has been discontinued; *note urllib.request.urlopen(): 293.
     corresponds to the old ‘urllib2.urlopen’.  Proxy handling, which
     was done by passing a dictionary parameter to ‘urllib.urlopen’, can
     be obtained by using *note ProxyHandler: 1b60. objects.

     The default opener raises an *note auditing event: 1a15.
     ‘urllib.Request’ with arguments ‘fullurl’, ‘data’, ‘headers’,
     ‘method’ taken from the request object.

     Changed in version 3.2: 'cafile' and 'capath' were added.

     HTTPS virtual hosts are now supported if possible (that is, if
     *note ssl.HAS_SNI: 36a6. is true).

     'data' can be an iterable object.

     Changed in version 3.3: 'cadefault' was added.

     Changed in version 3.4.3: 'context' was added.

     Changed in version 3.10: HTTPS connection now send an ALPN
     extension with protocol indicator ‘http/1.1’ when no 'context' is
     given.  Custom 'context' should set ALPN protocols with *note
     set_alpn_protocols(): e98.

     Changed in version 3.13: Remove 'cafile', 'capath' and 'cadefault'
     parameters: use the 'context' parameter instead.

 -- Function: urllib.request.install_opener (opener)

     Install an *note OpenerDirector: 3be7. instance as the default
     global opener.  Installing an opener is only necessary if you want
     urlopen to use that opener; otherwise, simply call *note
     OpenerDirector.open(): 1017. instead of *note urlopen(): 293.  The
     code does not check for a real ‘OpenerDirector’, and any class with
     the appropriate interface will work.

 -- Function: urllib.request.build_opener ([handler, ...])

     Return an *note OpenerDirector: 3be7. instance, which chains the
     handlers in the order given.  'handler's can be either instances of
     *note BaseHandler: 3beb, or subclasses of ‘BaseHandler’ (in which
     case it must be possible to call the constructor without any
     parameters).  Instances of the following classes will be in front
     of the 'handler's, unless the 'handler's contain them, instances of
     them or subclasses of them: *note ProxyHandler: 1b60. (if proxy
     settings are detected), *note UnknownHandler: 3be8, *note
     HTTPHandler: d23, *note HTTPDefaultErrorHandler: 3bec, *note
     HTTPRedirectHandler: 3bed, *note FTPHandler: 3bee, *note
     FileHandler: 3bef, *note HTTPErrorProcessor: 3bf0.

     If the Python installation has SSL support (i.e., if the *note ssl:
     d0. module can be imported), *note HTTPSHandler: 1269. will also be
     added.

     A *note BaseHandler: 3beb. subclass may also change its
     ‘handler_order’ attribute to modify its position in the handlers
     list.

 -- Function: urllib.request.pathname2url (path)

     Convert the given local path to a ‘file:’ URL. This function uses
     *note quote(): bc1. function to encode the path.  For historical
     reasons, the return value omits the ‘file:’ scheme prefix.  This
     example shows the function being used on Windows:

          >>> from urllib.request import pathname2url
          >>> path = 'C:\\Program Files'
          >>> 'file:' + pathname2url(path)
          'file:///C:/Program%20Files'

 -- Function: urllib.request.url2pathname (url)

     Convert the given ‘file:’ URL to a local path.  This function uses
     *note unquote(): 189e. to decode the URL. For historical reasons,
     the given value 'must' omit the ‘file:’ scheme prefix.  This
     example shows the function being used on Windows:

          >>> from urllib.request import url2pathname
          >>> url = 'file:///C:/Program%20Files'
          >>> url2pathname(url.removeprefix('file:'))
          'C:\\Program Files'

 -- Function: urllib.request.getproxies ()

     This helper function returns a dictionary of scheme to proxy server
     URL mappings.  It scans the environment for variables named
     ‘<scheme>_proxy’, in a case insensitive approach, for all operating
     systems first, and when it cannot find it, looks for proxy
     information from System Configuration for macOS and Windows Systems
     Registry for Windows.  If both lowercase and uppercase environment
     variables exist (and disagree), lowercase is preferred.

          Note: If the environment variable ‘REQUEST_METHOD’ is set,
          which usually indicates your script is running in a CGI
          environment, the environment variable ‘HTTP_PROXY’ (uppercase
          ‘_PROXY’) will be ignored.  This is because that variable can
          be injected by a client using the “Proxy:” HTTP header.  If
          you need to use an HTTP proxy in a CGI environment, either use
          ‘ProxyHandler’ explicitly, or make sure the variable name is
          in lowercase (or at least the ‘_proxy’ suffix).

The following classes are provided:

 -- Class: urllib.request.Request (url, data=None, headers={},
          origin_req_host=None, unverifiable=False, method=None)

     This class is an abstraction of a URL request.

     'url' should be a string containing a valid, properly encoded URL.

     'data' must be an object specifying additional data to send to the
     server, or ‘None’ if no such data is needed.  Currently HTTP
     requests are the only ones that use 'data'.  The supported object
     types include bytes, file-like objects, and iterables of bytes-like
     objects.  If no ‘Content-Length’ nor ‘Transfer-Encoding’ header
     field has been provided, *note HTTPHandler: d23. will set these
     headers according to the type of 'data'.  ‘Content-Length’ will be
     used to send bytes objects, while ‘Transfer-Encoding: chunked’ as
     specified in RFC 7230(3), Section 3.3.1 will be used to send files
     and other iterables.

     For an HTTP POST request method, 'data' should be a buffer in the
     standard ‘application/x-www-form-urlencoded’ format.  The *note
     urllib.parse.urlencode(): ec9. function takes a mapping or sequence
     of 2-tuples and returns an ASCII string in this format.  It should
     be encoded to bytes before being used as the 'data' parameter.

     'headers' should be a dictionary, and will be treated as if *note
     add_header(): 3bf1. was called with each key and value as
     arguments.  This is often used to “spoof” the ‘User-Agent’ header
     value, which is used by a browser to identify itself – some HTTP
     servers only allow requests coming from common browsers as opposed
     to scripts.  For example, Mozilla Firefox may identify itself as
     ‘"Mozilla/5.0 (X11; U; Linux i686) Gecko/20071127
     Firefox/2.0.0.11"’, while *note urllib: 108.’s default user agent
     string is ‘"Python-urllib/2.6"’ (on Python 2.6).  All header keys
     are sent in camel case.

     An appropriate ‘Content-Type’ header should be included if the
     'data' argument is present.  If this header has not been provided
     and 'data' is not ‘None’, ‘Content-Type:
     application/x-www-form-urlencoded’ will be added as a default.

     The next two arguments are only of interest for correct handling of
     third-party HTTP cookies:

     'origin_req_host' should be the request-host of the origin
     transaction, as defined by RFC 2965(4).  It defaults to
     ‘http.cookiejar.request_host(self)’.  This is the host name or IP
     address of the original request that was initiated by the user.
     For example, if the request is for an image in an HTML document,
     this should be the request-host of the request for the page
     containing the image.

     'unverifiable' should indicate whether the request is unverifiable,
     as defined by RFC 2965(5).  It defaults to ‘False’.  An
     unverifiable request is one whose URL the user did not have the
     option to approve.  For example, if the request is for an image in
     an HTML document, and the user had no option to approve the
     automatic fetching of the image, this should be true.

     'method' should be a string that indicates the HTTP request method
     that will be used (e.g.  ‘'HEAD'’).  If provided, its value is
     stored in the *note method: 1014. attribute and is used by *note
     get_method(): 11ad.  The default is ‘'GET'’ if 'data' is ‘None’ or
     ‘'POST'’ otherwise.  Subclasses may indicate a different default
     method by setting the ‘method’ attribute in the class itself.

          Note: The request will not work as expected if the data object
          is unable to deliver its content more than once (e.g.  a file
          or an iterable that can produce the content only once) and the
          request is retried for HTTP redirects or authentication.  The
          'data' is sent to the HTTP server right away after the
          headers.  There is no support for a 100-continue expectation
          in the library.

     Changed in version 3.3: *note Request.method: 1014. argument is
     added to the Request class.

     Changed in version 3.4: Default *note Request.method: 1014. may be
     indicated at the class level.

     Changed in version 3.6: Do not raise an error if the
     ‘Content-Length’ has not been provided and 'data' is neither ‘None’
     nor a bytes object.  Fall back to use chunked transfer encoding
     instead.

 -- Class: urllib.request.OpenerDirector

     The ‘OpenerDirector’ class opens URLs via *note BaseHandler: 3beb.s
     chained together.  It manages the chaining of handlers, and
     recovery from errors.

 -- Class: urllib.request.BaseHandler

     This is the base class for all registered handlers — and handles
     only the simple mechanics of registration.

 -- Class: urllib.request.HTTPDefaultErrorHandler

     A class which defines a default handler for HTTP error responses;
     all responses are turned into *note HTTPError: 1019. exceptions.

 -- Class: urllib.request.HTTPRedirectHandler

     A class to handle redirections.

 -- Class: urllib.request.HTTPCookieProcessor (cookiejar=None)

     A class to handle HTTP Cookies.

 -- Class: urllib.request.ProxyHandler (proxies=None)

     Cause requests to go through a proxy.  If 'proxies' is given, it
     must be a dictionary mapping protocol names to URLs of proxies.
     The default is to read the list of proxies from the environment
     variables ‘<protocol>_proxy’.  If no proxy environment variables
     are set, then in a Windows environment proxy settings are obtained
     from the registry’s Internet Settings section, and in a macOS
     environment proxy information is retrieved from the System
     Configuration Framework.

     To disable autodetected proxy pass an empty dictionary.

     The ‘no_proxy’ environment variable can be used to specify hosts
     which shouldn’t be reached via proxy; if set, it should be a
     comma-separated list of hostname suffixes, optionally with ‘:port’
     appended, for example ‘cern.ch,ncsa.uiuc.edu,some.host:8080’.

          Note: ‘HTTP_PROXY’ will be ignored if a variable
          ‘REQUEST_METHOD’ is set; see the documentation on *note
          getproxies(): 3be3.

 -- Class: urllib.request.HTTPPasswordMgr

     Keep a database of ‘(realm, uri) -> (user, password)’ mappings.

 -- Class: urllib.request.HTTPPasswordMgrWithDefaultRealm

     Keep a database of ‘(realm, uri) -> (user, password)’ mappings.  A
     realm of ‘None’ is considered a catch-all realm, which is searched
     if no other realm fits.

 -- Class: urllib.request.HTTPPasswordMgrWithPriorAuth

     A variant of *note HTTPPasswordMgrWithDefaultRealm: 3bf4. that also
     has a database of ‘uri -> is_authenticated’ mappings.  Can be used
     by a BasicAuth handler to determine when to send authentication
     credentials immediately instead of waiting for a ‘401’ response
     first.

     Added in version 3.5.

 -- Class: urllib.request.AbstractBasicAuthHandler (password_mgr=None)

     This is a mixin class that helps with HTTP authentication, both to
     the remote host and to a proxy.  'password_mgr', if given, should
     be something that is compatible with *note HTTPPasswordMgr: 3bf3.;
     refer to section *note HTTPPasswordMgr Objects: 3bf5. for
     information on the interface that must be supported.  If
     'passwd_mgr' also provides ‘is_authenticated’ and
     ‘update_authenticated’ methods (see *note
     HTTPPasswordMgrWithPriorAuth Objects: 3bf6.), then the handler will
     use the ‘is_authenticated’ result for a given URI to determine
     whether or not to send authentication credentials with the request.
     If ‘is_authenticated’ returns ‘True’ for the URI, credentials are
     sent.  If ‘is_authenticated’ is ‘False’, credentials are not sent,
     and then if a ‘401’ response is received the request is re-sent
     with the authentication credentials.  If authentication succeeds,
     ‘update_authenticated’ is called to set ‘is_authenticated’ ‘True’
     for the URI, so that subsequent requests to the URI or any of its
     super-URIs will automatically include the authentication
     credentials.

     Added in version 3.5: Added ‘is_authenticated’ support.

 -- Class: urllib.request.HTTPBasicAuthHandler (password_mgr=None)

     Handle authentication with the remote host.  'password_mgr', if
     given, should be something that is compatible with *note
     HTTPPasswordMgr: 3bf3.; refer to section *note HTTPPasswordMgr
     Objects: 3bf5. for information on the interface that must be
     supported.  HTTPBasicAuthHandler will raise a *note ValueError:
     202. when presented with a wrong Authentication scheme.

 -- Class: urllib.request.ProxyBasicAuthHandler (password_mgr=None)

     Handle authentication with the proxy.  'password_mgr', if given,
     should be something that is compatible with *note HTTPPasswordMgr:
     3bf3.; refer to section *note HTTPPasswordMgr Objects: 3bf5. for
     information on the interface that must be supported.

 -- Class: urllib.request.AbstractDigestAuthHandler (password_mgr=None)

     This is a mixin class that helps with HTTP authentication, both to
     the remote host and to a proxy.  'password_mgr', if given, should
     be something that is compatible with *note HTTPPasswordMgr: 3bf3.;
     refer to section *note HTTPPasswordMgr Objects: 3bf5. for
     information on the interface that must be supported.

 -- Class: urllib.request.HTTPDigestAuthHandler (password_mgr=None)

     Handle authentication with the remote host.  'password_mgr', if
     given, should be something that is compatible with *note
     HTTPPasswordMgr: 3bf3.; refer to section *note HTTPPasswordMgr
     Objects: 3bf5. for information on the interface that must be
     supported.  When both Digest Authentication Handler and Basic
     Authentication Handler are both added, Digest Authentication is
     always tried first.  If the Digest Authentication returns a 40x
     response again, it is sent to Basic Authentication handler to
     Handle.  This Handler method will raise a *note ValueError: 202.
     when presented with an authentication scheme other than Digest or
     Basic.

     Changed in version 3.3: Raise *note ValueError: 202. on unsupported
     Authentication Scheme.

 -- Class: urllib.request.ProxyDigestAuthHandler (password_mgr=None)

     Handle authentication with the proxy.  'password_mgr', if given,
     should be something that is compatible with *note HTTPPasswordMgr:
     3bf3.; refer to section *note HTTPPasswordMgr Objects: 3bf5. for
     information on the interface that must be supported.

 -- Class: urllib.request.HTTPHandler

     A class to handle opening of HTTP URLs.

 -- Class: urllib.request.HTTPSHandler (debuglevel=0, context=None,
          check_hostname=None)

     A class to handle opening of HTTPS URLs.  'context' and
     'check_hostname' have the same meaning as in *note
     http.client.HTTPSConnection: b5a.

     Changed in version 3.2: 'context' and 'check_hostname' were added.

 -- Class: urllib.request.FileHandler

     Open local files.

 -- Class: urllib.request.DataHandler

     Open data URLs.

     Added in version 3.4.

 -- Class: urllib.request.FTPHandler

     Open FTP URLs.

 -- Class: urllib.request.CacheFTPHandler

     Open FTP URLs, keeping a cache of open FTP connections to minimize
     delays.

 -- Class: urllib.request.UnknownHandler

     A catch-all class to handle unknown URLs.

 -- Class: urllib.request.HTTPErrorProcessor

     Process HTTP error responses.

* Menu:

* Request Objects::
* OpenerDirector Objects::
* BaseHandler Objects::
* HTTPRedirectHandler Objects::
* HTTPCookieProcessor Objects::
* ProxyHandler Objects::
* HTTPPasswordMgr Objects::
* HTTPPasswordMgrWithPriorAuth Objects::
* AbstractBasicAuthHandler Objects::
* HTTPBasicAuthHandler Objects::
* ProxyBasicAuthHandler Objects::
* AbstractDigestAuthHandler Objects::
* HTTPDigestAuthHandler Objects::
* ProxyDigestAuthHandler Objects::
* HTTPHandler Objects::
* HTTPSHandler Objects::
* FileHandler Objects::
* DataHandler Objects::
* FTPHandler Objects::
* CacheFTPHandler Objects::
* UnknownHandler Objects::
* HTTPErrorProcessor Objects::
* Examples: Examples<26>.
* Legacy interface::
* urllib.request Restrictions: urllib request Restrictions.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/urllib/request.py

   (2) https://requests.readthedocs.io/en/master/

   (3) https://datatracker.ietf.org/doc/html/rfc7230.html

   (4) https://datatracker.ietf.org/doc/html/rfc2965.html

   (5) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: Request Objects,  Next: OpenerDirector Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.1 Request Objects
........................

The following methods describe *note Request: 1013.’s public interface,
and so all may be overridden in subclasses.  It also defines several
public attributes that can be used by clients to inspect the parsed
request.

 -- Attribute: Request.full_url

     The original URL passed to the constructor.

     Changed in version 3.4.

     Request.full_url is a property with setter, getter and a deleter.
     Getting ‘full_url’ returns the original request URL with the
     fragment, if it was present.

 -- Attribute: Request.type

     The URI scheme.

 -- Attribute: Request.host

     The URI authority, typically a host, but may also contain a port
     separated by a colon.

 -- Attribute: Request.origin_req_host

     The original host for the request, without port.

 -- Attribute: Request.selector

     The URI path.  If the *note Request: 1013. uses a proxy, then
     selector will be the full URL that is passed to the proxy.

 -- Attribute: Request.data

     The entity body for the request, or ‘None’ if not specified.

     Changed in version 3.4: Changing value of ‘Request.data’ now
     deletes “Content-Length” header if it was previously set or
     calculated.

 -- Attribute: Request.unverifiable

     boolean, indicates whether the request is unverifiable as defined
     by RFC 2965(1).

 -- Attribute: Request.method

     The HTTP request method to use.  By default its value is *note
     None: 678, which means that *note get_method(): 11ad. will do its
     normal computation of the method to be used.  Its value can be set
     (thus overriding the default computation in ‘get_method()’) either
     by providing a default value by setting it at the class level in a
     *note Request: 1013. subclass, or by passing a value in to the
     ‘Request’ constructor via the 'method' argument.

     Added in version 3.3.

     Changed in version 3.4: A default value can now be set in
     subclasses; previously it could only be set via the constructor
     argument.

 -- Method: Request.get_method ()

     Return a string indicating the HTTP request method.  If *note
     Request.method: 1014. is not ‘None’, return its value, otherwise
     return ‘'GET'’ if *note Request.data: 1016. is ‘None’, or ‘'POST'’
     if it’s not.  This is only meaningful for HTTP requests.

     Changed in version 3.3: get_method now looks at the value of *note
     Request.method: 1014.

 -- Method: Request.add_header (key, val)

     Add another header to the request.  Headers are currently ignored
     by all handlers except HTTP handlers, where they are added to the
     list of headers sent to the server.  Note that there cannot be more
     than one header with the same name, and later calls will overwrite
     previous calls in case the 'key' collides.  Currently, this is no
     loss of HTTP functionality, since all headers which have meaning
     when used more than once have a (header-specific) way of gaining
     the same functionality using only one header.  Note that headers
     added using this method are also added to redirected requests.

 -- Method: Request.add_unredirected_header (key, header)

     Add a header that will not be added to a redirected request.

 -- Method: Request.has_header (header)

     Return whether the instance has the named header (checks both
     regular and unredirected).

 -- Method: Request.remove_header (header)

     Remove named header from the request instance (both from regular
     and unredirected headers).

     Added in version 3.4.

 -- Method: Request.get_full_url ()

     Return the URL given in the constructor.

     Changed in version 3.4.

     Returns *note Request.full_url: 1015.

 -- Method: Request.set_proxy (host, type)

     Prepare the request by connecting to a proxy server.  The 'host'
     and 'type' will replace those of the instance, and the instance’s
     selector will be the original URL given in the constructor.

 -- Method: Request.get_header (header_name, default=None)

     Return the value of the given header.  If the header is not
     present, return the default value.

 -- Method: Request.header_items ()

     Return a list of tuples (header_name, header_value) of the Request
     headers.

Changed in version 3.4: The request methods add_data, has_data,
get_data, get_type, get_host, get_selector, get_origin_req_host and
is_unverifiable that were deprecated since 3.3 have been removed.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: OpenerDirector Objects,  Next: BaseHandler Objects,  Prev: Request Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.2 OpenerDirector Objects
...............................

*note OpenerDirector: 3be7. instances have the following methods:

 -- Method: OpenerDirector.add_handler (handler)

     'handler' should be an instance of *note BaseHandler: 3beb.  The
     following methods are searched, and added to the possible chains
     (note that HTTP errors are a special case).  Note that, in the
     following, 'protocol' should be replaced with the actual protocol
     to handle, for example ‘http_response()’ would be the HTTP protocol
     response handler.  Also 'type' should be replaced with the actual
     HTTP code, for example ‘http_error_404()’ would handle HTTP 404
     errors.

        * ‘<protocol>_open()’ — signal that the handler knows how to
          open 'protocol' URLs.

          See *note BaseHandler.<protocol>_open(): 3c0b. for more
          information.

        * ‘http_error_<type>()’ — signal that the handler knows how to
          handle HTTP errors with HTTP error code 'type'.

          See *note BaseHandler.http_error_<nnn>(): 3c0c. for more
          information.

        * ‘<protocol>_error()’ — signal that the handler knows how to
          handle errors from (non-‘http’) 'protocol'.

        * ‘<protocol>_request()’ — signal that the handler knows how to
          pre-process 'protocol' requests.

          See *note BaseHandler.<protocol>_request(): 3c0d. for more
          information.

        * ‘<protocol>_response()’ — signal that the handler knows how to
          post-process 'protocol' responses.

          See *note BaseHandler.<protocol>_response(): 3c0e. for more
          information.

 -- Method: OpenerDirector.open (url, data=None[, timeout])

     Open the given 'url' (which can be a request object or a string),
     optionally passing the given 'data'.  Arguments, return values and
     exceptions raised are the same as those of *note urlopen(): 293.
     (which simply calls the ‘open()’ method on the currently installed
     global *note OpenerDirector: 3be7.).  The optional 'timeout'
     parameter specifies a timeout in seconds for blocking operations
     like the connection attempt (if not specified, the global default
     timeout setting will be used).  The timeout feature actually works
     only for HTTP, HTTPS and FTP connections.

 -- Method: OpenerDirector.error (proto, *args)

     Handle an error of the given protocol.  This will call the
     registered error handlers for the given protocol with the given
     arguments (which are protocol specific).  The HTTP protocol is a
     special case which uses the HTTP response code to determine the
     specific error handler; refer to the ‘http_error_<type>()’ methods
     of the handler classes.

     Return values and exceptions raised are the same as those of *note
     urlopen(): 293.

OpenerDirector objects open URLs in three stages:

The order in which these methods are called within each stage is
determined by sorting the handler instances.

  1. Every handler with a method named like ‘<protocol>_request()’ has
     that method called to pre-process the request.

  2. Handlers with a method named like ‘<protocol>_open()’ are called to
     handle the request.  This stage ends when a handler either returns
     a non-*note None: 678. value (ie.  a response), or raises an
     exception (usually *note URLError: 3be6.).  Exceptions are allowed
     to propagate.

     In fact, the above algorithm is first tried for methods named *note
     default_open(): 3c10.  If all such methods return *note None: 678,
     the algorithm is repeated for methods named like
     ‘<protocol>_open()’.  If all such methods return ‘None’, the
     algorithm is repeated for methods named *note unknown_open(): 3c11.

     Note that the implementation of these methods may involve calls of
     the parent *note OpenerDirector: 3be7. instance’s *note open():
     1017. and *note error(): 3c0f. methods.

  3. Every handler with a method named like ‘<protocol>_response()’ has
     that method called to post-process the response.


File: python.info,  Node: BaseHandler Objects,  Next: HTTPRedirectHandler Objects,  Prev: OpenerDirector Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.3 BaseHandler Objects
............................

*note BaseHandler: 3beb. objects provide a couple of methods that are
directly useful, and others that are meant to be used by derived
classes.  These are intended for direct use:

 -- Method: BaseHandler.add_parent (director)

     Add a director as parent.

 -- Method: BaseHandler.close ()

     Remove any parents.

The following attribute and methods should only be used by classes
derived from *note BaseHandler: 3beb.

     Note: The convention has been adopted that subclasses defining
     ‘<protocol>_request()’ or ‘<protocol>_response()’ methods are named
     ‘*Processor’; all others are named ‘*Handler’.

 -- Attribute: BaseHandler.parent

     A valid *note OpenerDirector: 3be7, which can be used to open using
     a different protocol, or handle errors.

 -- Method: BaseHandler.default_open (req)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should define it if they want to catch all URLs.

     This method, if implemented, will be called by the parent *note
     OpenerDirector: 3be7.  It should return a file-like object as
     described in the return value of the *note open(): 1017. method of
     ‘OpenerDirector’, or ‘None’.  It should raise *note URLError: 3be6,
     unless a truly exceptional thing happens (for example, *note
     MemoryError: 15ab. should not be mapped to ‘URLError’).

     This method will be called before any protocol-specific open
     method.

 -- Method: BaseHandler.<protocol>_open(req)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should define it if they want to handle URLs with the
     given protocol.

     This method, if defined, will be called by the parent *note
     OpenerDirector: 3be7.  Return values should be the same as for
     *note default_open(): 3c10.

 -- Method: BaseHandler.unknown_open (req)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should define it if they want to catch all URLs with no
     specific registered handler to open it.

     This method, if implemented, will be called by the *note parent:
     3c16. *note OpenerDirector: 3be7.  Return values should be the same
     as for *note default_open(): 3c10.

 -- Method: BaseHandler.http_error_default (req, fp, code, msg, hdrs)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should override it if they intend to provide a catch-all
     for otherwise unhandled HTTP errors.  It will be called
     automatically by the *note OpenerDirector: 3be7. getting the error,
     and should not normally be called in other circumstances.

     *note OpenerDirector: 3be7. will call this method with five
     positional arguments:

       1. a *note Request: 1013. object,

       2. a file-like object with the HTTP error body,

       3. the three-digit code of the error, as a string,

       4. the user-visible explanation of the code, as a string, and

       5. the headers of the error, as a mapping object.

     Return values and exceptions raised should be the same as those of
     *note urlopen(): 293.

 -- Method: BaseHandler.http_error_<nnn>(req, fp, code, msg, hdrs)

     'nnn' should be a three-digit HTTP error code.  This method is also
     not defined in *note BaseHandler: 3beb, but will be called, if it
     exists, on an instance of a subclass, when an HTTP error with code
     'nnn' occurs.

     Subclasses should override this method to handle specific HTTP
     errors.

     Arguments, return values and exceptions raised should be the same
     as for *note http_error_default(): 3c17.

 -- Method: BaseHandler.<protocol>_request(req)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should define it if they want to pre-process requests of
     the given protocol.

     This method, if defined, will be called by the parent *note
     OpenerDirector: 3be7.  'req' will be a *note Request: 1013. object.
     The return value should be a ‘Request’ object.

 -- Method: BaseHandler.<protocol>_response(req, response)

     This method is 'not' defined in *note BaseHandler: 3beb, but
     subclasses should define it if they want to post-process responses
     of the given protocol.

     This method, if defined, will be called by the parent *note
     OpenerDirector: 3be7.  'req' will be a *note Request: 1013. object.
     'response' will be an object implementing the same interface as the
     return value of *note urlopen(): 293.  The return value should
     implement the same interface as the return value of ‘urlopen()’.


File: python.info,  Node: HTTPRedirectHandler Objects,  Next: HTTPCookieProcessor Objects,  Prev: BaseHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.4 HTTPRedirectHandler Objects
....................................

     Note: Some HTTP redirections require action from this module’s
     client code.  If this is the case, *note HTTPError: 1019. is
     raised.  See RFC 2616(1) for details of the precise meanings of the
     various redirection codes.

     An *note HTTPError: 1019. exception raised as a security
     consideration if the HTTPRedirectHandler is presented with a
     redirected URL which is not an HTTP, HTTPS or FTP URL.

 -- Method: HTTPRedirectHandler.redirect_request (req, fp, code, msg,
          hdrs, newurl)

     Return a *note Request: 1013. or ‘None’ in response to a redirect.
     This is called by the default implementations of the
     ‘http_error_30*()’ methods when a redirection is received from the
     server.  If a redirection should take place, return a new ‘Request’
     to allow ‘http_error_30*()’ to perform the redirect to 'newurl'.
     Otherwise, raise *note HTTPError: 1019. if no other handler should
     try to handle this URL, or return ‘None’ if you can’t but another
     handler might.

          Note: The default implementation of this method does not
          strictly follow RFC 2616(2), which says that 301 and 302
          responses to ‘POST’ requests must not be automatically
          redirected without confirmation by the user.  In reality,
          browsers do allow automatic redirection of these responses,
          changing the POST to a ‘GET’, and the default implementation
          reproduces this behavior.

 -- Method: HTTPRedirectHandler.http_error_301 (req, fp, code, msg,
          hdrs)

     Redirect to the ‘Location:’ or ‘URI:’ URL. This method is called by
     the parent *note OpenerDirector: 3be7. when getting an HTTP ‘moved
     permanently’ response.

 -- Method: HTTPRedirectHandler.http_error_302 (req, fp, code, msg,
          hdrs)

     The same as *note http_error_301(): 3c1b, but called for the
     ‘found’ response.

 -- Method: HTTPRedirectHandler.http_error_303 (req, fp, code, msg,
          hdrs)

     The same as *note http_error_301(): 3c1b, but called for the ‘see
     other’ response.

 -- Method: HTTPRedirectHandler.http_error_307 (req, fp, code, msg,
          hdrs)

     The same as *note http_error_301(): 3c1b, but called for the
     ‘temporary redirect’ response.  It does not allow changing the
     request method from ‘POST’ to ‘GET’.

 -- Method: HTTPRedirectHandler.http_error_308 (req, fp, code, msg,
          hdrs)

     The same as *note http_error_301(): 3c1b, but called for the
     ‘permanent redirect’ response.  It does not allow changing the
     request method from ‘POST’ to ‘GET’.

     Added in version 3.11.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html

   (2) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: HTTPCookieProcessor Objects,  Next: ProxyHandler Objects,  Prev: HTTPRedirectHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.5 HTTPCookieProcessor Objects
....................................

*note HTTPCookieProcessor: 3bf2. instances have one attribute:

 -- Attribute: HTTPCookieProcessor.cookiejar

     The *note http.cookiejar.CookieJar: 3c23. in which cookies are
     stored.


File: python.info,  Node: ProxyHandler Objects,  Next: HTTPPasswordMgr Objects,  Prev: HTTPCookieProcessor Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.6 ProxyHandler Objects
.............................

 -- Method: ProxyHandler.<protocol>_open(request)

     The *note ProxyHandler: 1b60. will have a method
     ‘<protocol>_open()’ for every 'protocol' which has a proxy in the
     'proxies' dictionary given in the constructor.  The method will
     modify requests to go through the proxy, by calling
     ‘request.set_proxy()’, and call the next handler in the chain to
     actually execute the protocol.


File: python.info,  Node: HTTPPasswordMgr Objects,  Next: HTTPPasswordMgrWithPriorAuth Objects,  Prev: ProxyHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.7 HTTPPasswordMgr Objects
................................

These methods are available on *note HTTPPasswordMgr: 3bf3. and *note
HTTPPasswordMgrWithDefaultRealm: 3bf4. objects.

 -- Method: HTTPPasswordMgr.add_password (realm, uri, user, passwd)

     'uri' can be either a single URI, or a sequence of URIs.  'realm',
     'user' and 'passwd' must be strings.  This causes ‘(user, passwd)’
     to be used as authentication tokens when authentication for 'realm'
     and a super-URI of any of the given URIs is given.

 -- Method: HTTPPasswordMgr.find_user_password (realm, authuri)

     Get user/password for given realm and URI, if any.  This method
     will return ‘(None, None)’ if there is no matching user/password.

     For *note HTTPPasswordMgrWithDefaultRealm: 3bf4. objects, the realm
     ‘None’ will be searched if the given 'realm' has no matching
     user/password.


File: python.info,  Node: HTTPPasswordMgrWithPriorAuth Objects,  Next: AbstractBasicAuthHandler Objects,  Prev: HTTPPasswordMgr Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.8 HTTPPasswordMgrWithPriorAuth Objects
.............................................

This password manager extends *note HTTPPasswordMgrWithDefaultRealm:
3bf4. to support tracking URIs for which authentication credentials
should always be sent.

 -- Method: HTTPPasswordMgrWithPriorAuth.add_password (realm, uri, user,
          passwd, is_authenticated=False)

     'realm', 'uri', 'user', 'passwd' are as for *note
     HTTPPasswordMgr.add_password(): 3c27.  'is_authenticated' sets the
     initial value of the ‘is_authenticated’ flag for the given URI or
     list of URIs.  If 'is_authenticated' is specified as ‘True’,
     'realm' is ignored.

 -- Method: HTTPPasswordMgrWithPriorAuth.find_user_password (realm,
          authuri)

     Same as for *note HTTPPasswordMgrWithDefaultRealm: 3bf4. objects

 -- Method: HTTPPasswordMgrWithPriorAuth.update_authenticated (self,
          uri, is_authenticated=False)

     Update the ‘is_authenticated’ flag for the given 'uri' or list of
     URIs.

 -- Method: HTTPPasswordMgrWithPriorAuth.is_authenticated (self,
          authuri)

     Returns the current state of the ‘is_authenticated’ flag for the
     given URI.


File: python.info,  Node: AbstractBasicAuthHandler Objects,  Next: HTTPBasicAuthHandler Objects,  Prev: HTTPPasswordMgrWithPriorAuth Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.9 AbstractBasicAuthHandler Objects
.........................................

 -- Method: AbstractBasicAuthHandler.http_error_auth_reqed (authreq,
          host, req, headers)

     Handle an authentication request by getting a user/password pair,
     and re-trying the request.  'authreq' should be the name of the
     header where the information about the realm is included in the
     request, 'host' specifies the URL and path to authenticate for,
     'req' should be the (failed) *note Request: 1013. object, and
     'headers' should be the error headers.

     'host' is either an authority (e.g.  ‘"python.org"’) or a URL
     containing an authority component (e.g.  ‘"http://python.org/"’).
     In either case, the authority must not contain a userinfo component
     (so, ‘"python.org"’ and ‘"python.org:80"’ are fine,
     ‘"joe:password@python.org"’ is not).


File: python.info,  Node: HTTPBasicAuthHandler Objects,  Next: ProxyBasicAuthHandler Objects,  Prev: AbstractBasicAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.10 HTTPBasicAuthHandler Objects
......................................

 -- Method: HTTPBasicAuthHandler.http_error_401 (req, fp, code, msg,
          hdrs)

     Retry the request with authentication information, if available.


File: python.info,  Node: ProxyBasicAuthHandler Objects,  Next: AbstractDigestAuthHandler Objects,  Prev: HTTPBasicAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.11 ProxyBasicAuthHandler Objects
.......................................

 -- Method: ProxyBasicAuthHandler.http_error_407 (req, fp, code, msg,
          hdrs)

     Retry the request with authentication information, if available.


File: python.info,  Node: AbstractDigestAuthHandler Objects,  Next: HTTPDigestAuthHandler Objects,  Prev: ProxyBasicAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.12 AbstractDigestAuthHandler Objects
...........................................

 -- Method: AbstractDigestAuthHandler.http_error_auth_reqed (authreq,
          host, req, headers)

     'authreq' should be the name of the header where the information
     about the realm is included in the request, 'host' should be the
     host to authenticate to, 'req' should be the (failed) *note
     Request: 1013. object, and 'headers' should be the error headers.


File: python.info,  Node: HTTPDigestAuthHandler Objects,  Next: ProxyDigestAuthHandler Objects,  Prev: AbstractDigestAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.13 HTTPDigestAuthHandler Objects
.......................................

 -- Method: HTTPDigestAuthHandler.http_error_401 (req, fp, code, msg,
          hdrs)

     Retry the request with authentication information, if available.


File: python.info,  Node: ProxyDigestAuthHandler Objects,  Next: HTTPHandler Objects,  Prev: HTTPDigestAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.14 ProxyDigestAuthHandler Objects
........................................

 -- Method: ProxyDigestAuthHandler.http_error_407 (req, fp, code, msg,
          hdrs)

     Retry the request with authentication information, if available.


File: python.info,  Node: HTTPHandler Objects,  Next: HTTPSHandler Objects,  Prev: ProxyDigestAuthHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.15 HTTPHandler Objects
.............................

 -- Method: HTTPHandler.http_open (req)

     Send an HTTP request, which can be either GET or POST, depending on
     ‘req.data’.


File: python.info,  Node: HTTPSHandler Objects,  Next: FileHandler Objects,  Prev: HTTPHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.16 HTTPSHandler Objects
..............................

 -- Method: HTTPSHandler.https_open (req)

     Send an HTTPS request, which can be either GET or POST, depending
     on ‘req.data’.


File: python.info,  Node: FileHandler Objects,  Next: DataHandler Objects,  Prev: HTTPSHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.17 FileHandler Objects
.............................

 -- Method: FileHandler.file_open (req)

     Open the file locally, if there is no host name, or the host name
     is ‘'localhost'’.

     Changed in version 3.2: This method is applicable only for local
     hostnames.  When a remote hostname is given, a *note URLError:
     3be6. is raised.


File: python.info,  Node: DataHandler Objects,  Next: FTPHandler Objects,  Prev: FileHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.18 DataHandler Objects
.............................

 -- Method: DataHandler.data_open (req)

     Read a data URL. This kind of URL contains the content encoded in
     the URL itself.  The data URL syntax is specified in RFC 2397(1).
     This implementation ignores white spaces in base64 encoded data
     URLs so the URL may be wrapped in whatever source file it comes
     from.  But even though some browsers don’t mind about a missing
     padding at the end of a base64 encoded data URL, this
     implementation will raise a *note ValueError: 202. in that case.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2397.html


File: python.info,  Node: FTPHandler Objects,  Next: CacheFTPHandler Objects,  Prev: DataHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.19 FTPHandler Objects
............................

 -- Method: FTPHandler.ftp_open (req)

     Open the FTP file indicated by 'req'.  The login is always done
     with empty username and password.


File: python.info,  Node: CacheFTPHandler Objects,  Next: UnknownHandler Objects,  Prev: FTPHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.20 CacheFTPHandler Objects
.................................

*note CacheFTPHandler: 1839. objects are *note FTPHandler: 3bee. objects
with the following additional methods:

 -- Method: CacheFTPHandler.setTimeout (t)

     Set timeout of connections to 't' seconds.

 -- Method: CacheFTPHandler.setMaxConns (m)

     Set maximum number of cached connections to 'm'.


File: python.info,  Node: UnknownHandler Objects,  Next: HTTPErrorProcessor Objects,  Prev: CacheFTPHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.21 UnknownHandler Objects
................................

 -- Method: UnknownHandler.unknown_open ()

     Raise a *note URLError: 3be6. exception.


File: python.info,  Node: HTTPErrorProcessor Objects,  Next: Examples<26>,  Prev: UnknownHandler Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.22 HTTPErrorProcessor Objects
....................................

 -- Method: HTTPErrorProcessor.http_response (request, response)

     Process HTTP error responses.

     For 200 error codes, the response object is returned immediately.

     For non-200 error codes, this simply passes the job on to the
     ‘http_error_<type>()’ handler methods, via *note
     OpenerDirector.error(): 3c0f.  Eventually, *note
     HTTPDefaultErrorHandler: 3bec. will raise an *note HTTPError: 1019.
     if no other handler handles the error.

 -- Method: HTTPErrorProcessor.https_response (request, response)

     Process HTTPS error responses.

     The behavior is same as *note http_response(): 3c56.


File: python.info,  Node: Examples<26>,  Next: Legacy interface,  Prev: HTTPErrorProcessor Objects,  Up: urllib request — Extensible library for opening URLs

5.22.4.23 Examples
..................

In addition to the examples below, more examples are given in *note
HOWTO Fetch Internet Resources Using The urllib Package: 3c5a.

This example gets the python.org main page and displays the first 300
bytes of it:

     >>> import urllib.request
     >>> with urllib.request.urlopen('http://www.python.org/') as f:
     ...     print(f.read(300))
     ...
     b'<!doctype html>\n<!--[if lt IE 7]>   <html class="no-js ie6 lt-ie7 lt-ie8 lt-ie9">   <![endif]-->\n<!--[if IE 7]>      <html class="no-js ie7 lt-ie8 lt-ie9">          <![endif]-->\n<!--[if IE 8]>      <html class="no-js ie8 lt-ie9">

Note that urlopen returns a bytes object.  This is because there is no
way for urlopen to automatically determine the encoding of the byte
stream it receives from the HTTP server.  In general, a program will
decode the returned bytes object to string once it determines or guesses
the appropriate encoding.

The following HTML spec document,
‘https://html.spec.whatwg.org/#charset’, lists the various ways in which
an HTML or an XML document could have specified its encoding
information.

For additional information, see the W3C document:
‘https://www.w3.org/International/questions/qa-html-encoding-declarations’.

As the python.org website uses 'utf-8' encoding as specified in its meta
tag, we will use the same for decoding the bytes object:

     >>> with urllib.request.urlopen('http://www.python.org/') as f:
     ...     print(f.read(100).decode('utf-8'))
     ...
     <!doctype html>
     <!--[if lt IE 7]>   <html class="no-js ie6 lt-ie7 lt-ie8 lt-ie9">   <![endif]-->
     <!-

It is also possible to achieve the same result without using the *note
context manager: 5d7. approach:

     >>> import urllib.request
     >>> f = urllib.request.urlopen('http://www.python.org/')
     >>> try:
     ...     print(f.read(100).decode('utf-8'))
     ... finally:
     ...     f.close()
     ...
     <!doctype html>
     <!--[if lt IE 7]>   <html class="no-js ie6 lt-ie7 lt-ie8 lt-ie9">   <![endif]-->
     <!--

In the following example, we are sending a data-stream to the stdin of a
CGI and reading the data it returns to us.  Note that this example will
only work when the Python installation supports SSL.

     >>> import urllib.request
     >>> req = urllib.request.Request(url='https://localhost/cgi-bin/test.cgi',
     ...                       data=b'This data is passed to stdin of the CGI')
     >>> with urllib.request.urlopen(req) as f:
     ...     print(f.read().decode('utf-8'))
     ...
     Got Data: "This data is passed to stdin of the CGI"

The code for the sample CGI used in the above example is:

     #!/usr/bin/env python
     import sys
     data = sys.stdin.read()
     print('Content-type: text/plain\n\nGot Data: "%s"' % data)

Here is an example of doing a ‘PUT’ request using *note Request: 1013.:

     import urllib.request
     DATA = b'some data'
     req = urllib.request.Request(url='http://localhost:8080', data=DATA, method='PUT')
     with urllib.request.urlopen(req) as f:
         pass
     print(f.status)
     print(f.reason)

Use of Basic HTTP Authentication:

     import urllib.request
     # Create an OpenerDirector with support for Basic HTTP Authentication...
     auth_handler = urllib.request.HTTPBasicAuthHandler()
     auth_handler.add_password(realm='PDQ Application',
                               uri='https://mahler:8092/site-updates.py',
                               user='klem',
                               passwd='kadidd!ehopper')
     opener = urllib.request.build_opener(auth_handler)
     # ...and install it globally so it can be used with urlopen.
     urllib.request.install_opener(opener)
     with urllib.request.urlopen('http://www.example.com/login.html') as f:
         print(f.read().decode('utf-8'))

*note build_opener(): 3bea. provides many handlers by default, including
a *note ProxyHandler: 1b60.  By default, ‘ProxyHandler’ uses the
environment variables named ‘<scheme>_proxy’, where ‘<scheme>’ is the
URL scheme involved.  For example, the ‘http_proxy’ environment variable
is read to obtain the HTTP proxy’s URL.

This example replaces the default *note ProxyHandler: 1b60. with one
that uses programmatically supplied proxy URLs, and adds proxy
authorization support with *note ProxyBasicAuthHandler: 3bf8.

     proxy_handler = urllib.request.ProxyHandler({'http': 'http://www.example.com:3128/'})
     proxy_auth_handler = urllib.request.ProxyBasicAuthHandler()
     proxy_auth_handler.add_password('realm', 'host', 'username', 'password')

     opener = urllib.request.build_opener(proxy_handler, proxy_auth_handler)
     # This time, rather than install the OpenerDirector, we use it directly:
     with opener.open('http://www.example.com/login.html') as f:
        print(f.read().decode('utf-8'))

Adding HTTP headers:

Use the 'headers' argument to the *note Request: 1013. constructor, or:

     import urllib.request
     req = urllib.request.Request('http://www.example.com/')
     req.add_header('Referer', 'http://www.python.org/')
     # Customize the default User-Agent header value:
     req.add_header('User-Agent', 'urllib-example/0.1 (Contact: . . .)')
     with urllib.request.urlopen(req) as f:
         print(f.read().decode('utf-8'))

*note OpenerDirector: 3be7. automatically adds a ‘User-Agent’ header to
every *note Request: 1013.  To change this:

     import urllib.request
     opener = urllib.request.build_opener()
     opener.addheaders = [('User-agent', 'Mozilla/5.0')]
     with opener.open('http://www.example.com/') as f:
        print(f.read().decode('utf-8'))

Also, remember that a few standard headers (‘Content-Length’,
‘Content-Type’ and ‘Host’) are added when the *note Request: 1013. is
passed to *note urlopen(): 293. (or *note OpenerDirector.open(): 1017.).
Here is an example session that uses the ‘GET’ method to retrieve a URL
containing parameters:

     >>> import urllib.request
     >>> import urllib.parse
     >>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
     >>> url = "http://www.musi-cal.com/cgi-bin/query?%s" % params
     >>> with urllib.request.urlopen(url) as f:
     ...     print(f.read().decode('utf-8'))
     ...

The following example uses the ‘POST’ method instead.  Note that params
output from urlencode is encoded to bytes before it is sent to urlopen
as data:

     >>> import urllib.request
     >>> import urllib.parse
     >>> data = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
     >>> data = data.encode('ascii')
     >>> with urllib.request.urlopen("http://requestb.in/xrbl82xr", data) as f:
     ...     print(f.read().decode('utf-8'))
     ...

The following example uses an explicitly specified HTTP proxy,
overriding environment settings:

     >>> import urllib.request
     >>> proxies = {'http': 'http://proxy.example.com:8080/'}
     >>> opener = urllib.request.FancyURLopener(proxies)
     >>> with opener.open("http://www.python.org") as f:
     ...     f.read().decode('utf-8')
     ...

The following example uses no proxies at all, overriding environment
settings:

     >>> import urllib.request
     >>> opener = urllib.request.FancyURLopener({})
     >>> with opener.open("http://www.python.org/") as f:
     ...     f.read().decode('utf-8')
     ...


File: python.info,  Node: Legacy interface,  Next: urllib request Restrictions,  Prev: Examples<26>,  Up: urllib request — Extensible library for opening URLs

5.22.4.24 Legacy interface
..........................

The following functions and classes are ported from the Python 2 module
‘urllib’ (as opposed to ‘urllib2’).  They might become deprecated at
some point in the future.

 -- Function: urllib.request.urlretrieve (url, filename=None,
          reporthook=None, data=None)

     Copy a network object denoted by a URL to a local file.  If the URL
     points to a local file, the object will not be copied unless
     filename is supplied.  Return a tuple ‘(filename, headers)’ where
     'filename' is the local file name under which the object can be
     found, and 'headers' is whatever the ‘info()’ method of the object
     returned by *note urlopen(): 293. returned (for a remote object).
     Exceptions are the same as for ‘urlopen()’.

     The second argument, if present, specifies the file location to
     copy to (if absent, the location will be a tempfile with a
     generated name).  The third argument, if present, is a callable
     that will be called once on establishment of the network connection
     and once after each block read thereafter.  The callable will be
     passed three arguments; a count of blocks transferred so far, a
     block size in bytes, and the total size of the file.  The third
     argument may be ‘-1’ on older FTP servers which do not return a
     file size in response to a retrieval request.

     The following example illustrates the most common usage scenario:

          >>> import urllib.request
          >>> local_filename, headers = urllib.request.urlretrieve('http://python.org/')
          >>> html = open(local_filename)
          >>> html.close()

     If the 'url' uses the ‘http:’ scheme identifier, the optional
     'data' argument may be given to specify a ‘POST’ request (normally
     the request type is ‘GET’).  The 'data' argument must be a bytes
     object in standard ‘application/x-www-form-urlencoded’ format; see
     the *note urllib.parse.urlencode(): ec9. function.

     ‘urlretrieve()’ will raise *note ContentTooShortError: 3c5e. when
     it detects that the amount of data available was less than the
     expected amount (which is the size reported by a 'Content-Length'
     header).  This can occur, for example, when the download is
     interrupted.

     The 'Content-Length' is treated as a lower bound: if there’s more
     data to read, urlretrieve reads more data, but if less data is
     available, it raises the exception.

     You can still retrieve the downloaded data in this case, it is
     stored in the ‘content’ attribute of the exception instance.

     If no 'Content-Length' header was supplied, urlretrieve can not
     check the size of the data it has downloaded, and just returns it.
     In this case you just have to assume that the download was
     successful.

 -- Function: urllib.request.urlcleanup ()

     Cleans up temporary files that may have been left behind by
     previous calls to *note urlretrieve(): 3c5d.

 -- Class: urllib.request.URLopener (proxies=None, **x509)

     Deprecated since version 3.3.

     Base class for opening and reading URLs.  Unless you need to
     support opening objects using schemes other than ‘http:’, ‘ftp:’,
     or ‘file:’, you probably want to use *note FancyURLopener: 30f.

     By default, the ‘URLopener’ class sends a ‘User-Agent’ header of
     ‘urllib/VVV’, where 'VVV' is the *note urllib: 108. version number.
     Applications can define their own ‘User-Agent’ header by
     subclassing ‘URLopener’ or *note FancyURLopener: 30f. and setting
     the class attribute *note version: 3c5f. to an appropriate string
     value in the subclass definition.

     The optional 'proxies' parameter should be a dictionary mapping
     scheme names to proxy URLs, where an empty dictionary turns proxies
     off completely.  Its default value is ‘None’, in which case
     environmental proxy settings will be used if present, as discussed
     in the definition of *note urlopen(): 293, above.

     Additional keyword parameters, collected in 'x509', may be used for
     authentication of the client when using the ‘https:’ scheme.  The
     keywords 'key_file' and 'cert_file' are supported to provide an SSL
     key and certificate; both are needed to support client
     authentication.

     ‘URLopener’ objects will raise an *note OSError: 41a. exception if
     the server returns an error code.

      -- Method: open (fullurl, data=None)

          Open 'fullurl' using the appropriate protocol.  This method
          sets up cache and proxy information, then calls the
          appropriate open method with its input arguments.  If the
          scheme is not recognized, *note open_unknown(): 3c61. is
          called.  The 'data' argument has the same meaning as the
          'data' argument of *note urlopen(): 293.

          This method always quotes 'fullurl' using *note quote(): bc1.

      -- Method: open_unknown (fullurl, data=None)

          Overridable interface to open unknown URL types.

      -- Method: retrieve (url, filename=None, reporthook=None,
               data=None)

          Retrieves the contents of 'url' and places it in 'filename'.
          The return value is a tuple consisting of a local filename and
          either an *note email.message.Message: 27c. object containing
          the response headers (for remote URLs) or ‘None’ (for local
          URLs).  The caller must then open and read the contents of
          'filename'.  If 'filename' is not given and the URL refers to
          a local file, the input filename is returned.  If the URL is
          non-local and 'filename' is not given, the filename is the
          output of *note tempfile.mktemp(): 19d6. with a suffix that
          matches the suffix of the last path component of the input
          URL.  If 'reporthook' is given, it must be a function
          accepting three numeric parameters: A chunk number, the
          maximum size chunks are read in and the total size of the
          download (-1 if unknown).  It will be called once at the start
          and after each chunk of data is read from the network.
          'reporthook' is ignored for local URLs.

          If the 'url' uses the ‘http:’ scheme identifier, the optional
          'data' argument may be given to specify a ‘POST’ request
          (normally the request type is ‘GET’).  The 'data' argument
          must in standard ‘application/x-www-form-urlencoded’ format;
          see the *note urllib.parse.urlencode(): ec9. function.

      -- Attribute: version

          Variable that specifies the user agent of the opener object.
          To get *note urllib: 108. to tell servers that it is a
          particular user agent, set this in a subclass as a class
          variable or in the constructor before calling the base
          constructor.

 -- Class: urllib.request.FancyURLopener (...)

     Deprecated since version 3.3.

     ‘FancyURLopener’ subclasses *note URLopener: 30e. providing default
     handling for the following HTTP response codes: 301, 302, 303, 307
     and 401.  For the 30x response codes listed above, the ‘Location’
     header is used to fetch the actual URL. For 401 response codes
     (authentication required), basic HTTP authentication is performed.
     For the 30x response codes, recursion is bounded by the value of
     the 'maxtries' attribute, which defaults to 10.

     For all other response codes, the method *note
     http_error_default(): 3c17. is called which you can override in
     subclasses to handle the error appropriately.

          Note: According to the letter of RFC 2616(1), 301 and 302
          responses to POST requests must not be automatically
          redirected without confirmation by the user.  In reality,
          browsers do allow automatic redirection of these responses,
          changing the POST to a GET, and *note urllib: 108. reproduces
          this behaviour.

     The parameters to the constructor are the same as those for *note
     URLopener: 30e.

          Note: When performing basic authentication, a ‘FancyURLopener’
          instance calls its *note prompt_user_passwd(): 3c62. method.
          The default implementation asks the users for the required
          information on the controlling terminal.  A subclass may
          override this method to support more appropriate behavior if
          needed.

     The ‘FancyURLopener’ class offers one additional method that should
     be overloaded to provide the appropriate behavior:

      -- Method: prompt_user_passwd (host, realm)

          Return information needed to authenticate the user at the
          given host in the specified security realm.  The return value
          should be a tuple, ‘(user, password)’, which can be used for
          basic authentication.

          The implementation prompts for this information on the
          terminal; an application should override this method to use an
          appropriate interaction model in the local environment.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: urllib request Restrictions,  Prev: Legacy interface,  Up: urllib request — Extensible library for opening URLs

5.22.4.25 ‘urllib.request’ Restrictions
.......................................

   * Currently, only the following protocols are supported: HTTP
     (versions 0.9 and 1.0), FTP, local files, and data URLs.

     Changed in version 3.4: Added support for data URLs.

   * The caching feature of *note urlretrieve(): 3c5d. has been disabled
     until someone finds the time to hack proper processing of
     Expiration time headers.

   * There should be a function to query whether a particular URL is in
     the cache.

   * For backward compatibility, if a URL appears to point to a local
     file but the file can’t be opened, the URL is re-interpreted using
     the FTP protocol.  This can sometimes cause confusing error
     messages.

   * The *note urlopen(): 293. and *note urlretrieve(): 3c5d. functions
     can cause arbitrarily long delays while waiting for a network
     connection to be set up.  This means that it is difficult to build
     an interactive web client using these functions without using
     threads.

   * The data returned by *note urlopen(): 293. or *note urlretrieve():
     3c5d. is the raw data returned by the server.  This may be binary
     data (such as an image), plain text or (for example) HTML. The HTTP
     protocol provides type information in the reply header, which can
     be inspected by looking at the ‘Content-Type’ header.  If the
     returned data is HTML, you can use the module *note html.parser:
     6d. to parse it.

   * The code handling the FTP protocol cannot differentiate between a
     file and a directory.  This can lead to unexpected behavior when
     attempting to read a URL that points to a file that is not
     accessible.  If the URL ends in a ‘/’, it is assumed to refer to a
     directory and will be handled accordingly.  But if an attempt to
     read a file leads to a 550 error (meaning the URL cannot be found
     or is not accessible, often for permission reasons), then the path
     is treated as a directory in order to handle the case when a
     directory is specified by a URL but the trailing ‘/’ has been left
     off.  This can cause misleading results when you try to fetch a
     file whose read permissions make it inaccessible; the FTP code will
     try to read it, fail with a 550 error, and then perform a directory
     listing for the unreadable file.  If fine-grained control is
     needed, consider using the *note ftplib: 5e. module, subclassing
     *note FancyURLopener: 30f, or changing '_urlopener' to meet your
     needs.


File: python.info,  Node: urllib response — Response classes used by urllib,  Next: urllib parse — Parse URLs into components,  Prev: urllib request — Extensible library for opening URLs,  Up: Internet Protocols and Support

5.22.5 ‘urllib.response’ — Response classes used by urllib
----------------------------------------------------------

The ‘urllib.response’ module defines functions and classes which define
a minimal file-like interface, including ‘read()’ and ‘readline()’.
Functions defined by this module are used internally by the *note
urllib.request: 10b. module.  The typical response object is a *note
urllib.response.addinfourl: 3be4. instance:

 -- Class: urllib.response.addinfourl

      -- Attribute: url

          URL of the resource retrieved, commonly used to determine if a
          redirect was followed.

      -- Attribute: headers

          Returns the headers of the response in the form of an *note
          EmailMessage: 27b. instance.

      -- Attribute: status

          Added in version 3.9.

          Status code returned by server.

      -- Method: geturl ()

          Deprecated since version 3.9: Deprecated in favor of *note
          url: 3c65.

      -- Method: info ()

          Deprecated since version 3.9: Deprecated in favor of *note
          headers: 3c66.

      -- Attribute: code

          Deprecated since version 3.9: Deprecated in favor of *note
          status: 3c67.

      -- Method: getcode ()

          Deprecated since version 3.9: Deprecated in favor of *note
          status: 3c67.


File: python.info,  Node: urllib parse — Parse URLs into components,  Next: urllib error — Exception classes raised by urllib request,  Prev: urllib response — Response classes used by urllib,  Up: Internet Protocols and Support

5.22.6 ‘urllib.parse’ — Parse URLs into components
--------------------------------------------------

'Source code:' Lib/urllib/parse.py(1)

__________________________________________________________________

This module defines a standard interface to break Uniform Resource
Locator (URL) strings up in components (addressing scheme, network
location, path etc.), to combine the components back into a URL string,
and to convert a “relative URL” to an absolute URL given a “base URL.”

The module has been designed to match the internet RFC on Relative
Uniform Resource Locators.  It supports the following URL schemes:
‘file’, ‘ftp’, ‘gopher’, ‘hdl’, ‘http’, ‘https’, ‘imap’,
‘itms-services’, ‘mailto’, ‘mms’, ‘news’, ‘nntp’, ‘prospero’, ‘rsync’,
‘rtsp’, ‘rtsps’, ‘rtspu’, ‘sftp’, ‘shttp’, ‘sip’, ‘sips’, ‘snews’,
‘svn’, ‘svn+ssh’, ‘telnet’, ‘wais’, ‘ws’, ‘wss’.

'CPython implementation detail:' The inclusion of the ‘itms-services’
URL scheme can prevent an app from passing Apple’s App Store review
process for the macOS and iOS App Stores.  Handling for the
‘itms-services’ scheme is always removed on iOS; on macOS, it 'may' be
removed if CPython has been built with the *note
-with-app-store-compliance: 16fc. option.

The ‘urllib.parse’ module defines functions that fall into two broad
categories: URL parsing and URL quoting.  These are covered in detail in
the following sections.

This module’s functions use the deprecated term ‘netloc’ (or ‘net_loc’),
which was introduced in RFC 1808(2).  However, this term has been
obsoleted by RFC 3986(3), which introduced the term ‘authority’ as its
replacement.  The use of ‘netloc’ is continued for backward
compatibility.

* Menu:

* URL Parsing::
* URL parsing security::
* Parsing ASCII Encoded Bytes::
* Structured Parse Results::
* URL Quoting::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/urllib/parse.py

   (2) https://datatracker.ietf.org/doc/html/rfc1808.html

   (3) https://datatracker.ietf.org/doc/html/rfc3986.html


File: python.info,  Node: URL Parsing,  Next: URL parsing security,  Up: urllib parse — Parse URLs into components

5.22.6.1 URL Parsing
....................

The URL parsing functions focus on splitting a URL string into its
components, or on combining URL components into a URL string.

 -- Function: urllib.parse.urlsplit (urlstring, scheme=None,
          allow_fragments=True)

     Parse a URL into five components, returning a 5-item *note named
     tuple: 651. *note SplitResult: 3c70. or *note SplitResultBytes:
     3c71.  This corresponds to the general structure of a URL:
     ‘scheme://netloc/path?query#fragment’.  Each tuple item is a
     string, possibly empty.  The components are not broken up into
     smaller parts (for example, the network location is a single
     string), and % escapes are not expanded.  The delimiters as shown
     above are not part of the result, except for a leading slash in the
     'path' component, which is retained if present.  For example:

          >>> from urllib.parse import urlsplit
          >>> urlsplit("scheme://netloc/path?query#fragment")
          SplitResult(scheme='scheme', netloc='netloc', path='/path',
                      query='query', fragment='fragment')
          >>> o = urlsplit("http://docs.python.org:80/3/library/urllib.parse.html?"
          ...              "highlight=params#url-parsing")
          >>> o
          SplitResult(scheme='http', netloc='docs.python.org:80',
                      path='/3/library/urllib.parse.html',
                      query='highlight=params', fragment='url-parsing')
          >>> o.scheme
          'http'
          >>> o.netloc
          'docs.python.org:80'
          >>> o.hostname
          'docs.python.org'
          >>> o.port
          80
          >>> o._replace(fragment="").geturl()
          'http://docs.python.org:80/3/library/urllib.parse.html?highlight=params'

     Following the syntax specifications in RFC 1808(1), ‘urlsplit()’
     recognizes a netloc only if it is properly introduced by ‘//’.
     Otherwise the input is presumed to be a relative URL and thus to
     start with a path component.

          >>> from urllib.parse import urlsplit
          >>> urlsplit('//www.cwi.nl:80/%7Eguido/Python.html')
          SplitResult(scheme='', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
                      query='', fragment='')
          >>> urlsplit('www.cwi.nl/%7Eguido/Python.html')
          SplitResult(scheme='', netloc='', path='www.cwi.nl/%7Eguido/Python.html',
                      query='', fragment='')
          >>> urlsplit('help/Python.html')
          SplitResult(scheme='', netloc='', path='help/Python.html',
                      query='', fragment='')

     The 'scheme' argument gives the default addressing scheme, to be
     used only if the URL does not specify one.  It should be the same
     type (text or bytes) as 'urlstring', except that the default value
     ‘''’ is always allowed, and is automatically converted to ‘b''’ if
     appropriate.

     If the 'allow_fragments' argument is false, fragment identifiers
     are not recognized.  Instead, they are parsed as part of the path,
     parameters or query component, and ‘fragment’ is set to the empty
     string in the return value.

     The return value is a *note named tuple: 651, which means that its
     items can be accessed by index or as named attributes, which are:

     Attribute              Index       Value                         Value if not present
                                                                      
     ----------------------------------------------------------------------------------------------
                                                                      
     ‘scheme’               0           URL scheme specifier          'scheme' parameter
                                                                      
                                                                      
     ‘netloc’               1           Network location part         empty string
                                                                      
                                                                      
     ‘path’                 2           Hierarchical path             empty string
                                                                      
                                                                      
     ‘query’                3           Query component               empty string
                                                                      
                                                                      
     ‘fragment’             4           Fragment identifier           empty string
                                                                      
                                                                      
     ‘username’                         User name                     *note None: 678.
                                                                      
                                                                      
     ‘password’                         Password                      *note None: 678.
                                                                      
                                                                      
     ‘hostname’                         Host name (lower case)        *note None: 678.
                                                                      
                                                                      
     ‘port’                             Port number as integer, if    *note None: 678.
                                        present                       
                                        

     Reading the ‘port’ attribute will raise a *note ValueError: 202. if
     an invalid port is specified in the URL. See section *note
     Structured Parse Results: 3c72. for more information on the result
     object.

     Unmatched square brackets in the ‘netloc’ attribute will raise a
     *note ValueError: 202.

     Characters in the ‘netloc’ attribute that decompose under NFKC
     normalization (as used by the IDNA encoding) into any of ‘/’, ‘?’,
     ‘#’, ‘@’, or ‘:’ will raise a *note ValueError: 202.  If the URL is
     decomposed before parsing, no error will be raised.

     Following some of the WHATWG spec(2) that updates RFC 3986(3),
     leading C0 control and space characters are stripped from the URL.
     ‘\n’, ‘\r’ and tab ‘\t’ characters are removed from the URL at any
     position.

     As is the case with all named tuples, the subclass has a few
     additional methods and attributes that are particularly useful.
     One such method is ‘_replace()’.  The ‘_replace()’ method will
     return a new *note SplitResult: 3c70. object replacing specified
     fields with new values.

          >>> from urllib.parse import urlsplit
          >>> u = urlsplit('//www.cwi.nl:80/%7Eguido/Python.html')
          >>> u
          SplitResult(scheme='', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
                      query='', fragment='')
          >>> u._replace(scheme='http')
          SplitResult(scheme='http', netloc='www.cwi.nl:80', path='/%7Eguido/Python.html',
                      query='', fragment='')

          Warning: ‘urlsplit()’ does not perform validation.  See *note
          URL parsing security: 3c73. for details.

     Changed in version 3.2: Added IPv6 URL parsing capabilities.

     Changed in version 3.3: The fragment is now parsed for all URL
     schemes (unless 'allow_fragments' is false), in accordance with RFC
     3986(4).  Previously, an allowlist of schemes that support
     fragments existed.

     Changed in version 3.6: Out-of-range port numbers now raise *note
     ValueError: 202, instead of returning *note None: 678.

     Changed in version 3.8: Characters that affect netloc parsing under
     NFKC normalization will now raise *note ValueError: 202.

     Changed in version 3.10: ASCII newline and tab characters are
     stripped from the URL.

     Changed in version 3.12: Leading WHATWG C0 control and space
     characters are stripped from the URL.

 -- Function: urllib.parse.parse_qs (qs, keep_blank_values=False,
          strict_parsing=False, encoding='utf-8', errors='replace',
          max_num_fields=None, separator='&')

     Parse a query string given as a string argument (data of type
     ‘application/x-www-form-urlencoded’).  Data are returned as a
     dictionary.  The dictionary keys are the unique query variable
     names and the values are lists of values for each name.

     The optional argument 'keep_blank_values' is a flag indicating
     whether blank values in percent-encoded queries should be treated
     as blank strings.  A true value indicates that blanks should be
     retained as blank strings.  The default false value indicates that
     blank values are to be ignored and treated as if they were not
     included.

     The optional argument 'strict_parsing' is a flag indicating what to
     do with parsing errors.  If false (the default), errors are
     silently ignored.  If true, errors raise a *note ValueError: 202.
     exception.

     The optional 'encoding' and 'errors' parameters specify how to
     decode percent-encoded sequences into Unicode characters, as
     accepted by the *note bytes.decode(): 8df. method.

     The optional argument 'max_num_fields' is the maximum number of
     fields to read.  If set, then throws a *note ValueError: 202. if
     there are more than 'max_num_fields' fields read.

     The optional argument 'separator' is the symbol to use for
     separating the query arguments.  It defaults to ‘&’.

     Use the *note urllib.parse.urlencode(): ec9. function (with the
     ‘doseq’ parameter set to ‘True’) to convert such dictionaries into
     query strings.

     Changed in version 3.2: Add 'encoding' and 'errors' parameters.

     Changed in version 3.8: Added 'max_num_fields' parameter.

     Changed in version 3.10: Added 'separator' parameter with the
     default value of ‘&’.  Python versions earlier than Python 3.10
     allowed using both ‘;’ and ‘&’ as query parameter separator.  This
     has been changed to allow only a single separator key, with ‘&’ as
     the default separator.

 -- Function: urllib.parse.parse_qsl (qs, keep_blank_values=False,
          strict_parsing=False, encoding='utf-8', errors='replace',
          max_num_fields=None, separator='&')

     Parse a query string given as a string argument (data of type
     ‘application/x-www-form-urlencoded’).  Data are returned as a list
     of name, value pairs.

     The optional argument 'keep_blank_values' is a flag indicating
     whether blank values in percent-encoded queries should be treated
     as blank strings.  A true value indicates that blanks should be
     retained as blank strings.  The default false value indicates that
     blank values are to be ignored and treated as if they were not
     included.

     The optional argument 'strict_parsing' is a flag indicating what to
     do with parsing errors.  If false (the default), errors are
     silently ignored.  If true, errors raise a *note ValueError: 202.
     exception.

     The optional 'encoding' and 'errors' parameters specify how to
     decode percent-encoded sequences into Unicode characters, as
     accepted by the *note bytes.decode(): 8df. method.

     The optional argument 'max_num_fields' is the maximum number of
     fields to read.  If set, then throws a *note ValueError: 202. if
     there are more than 'max_num_fields' fields read.

     The optional argument 'separator' is the symbol to use for
     separating the query arguments.  It defaults to ‘&’.

     Use the *note urllib.parse.urlencode(): ec9. function to convert
     such lists of pairs into query strings.

     Changed in version 3.2: Add 'encoding' and 'errors' parameters.

     Changed in version 3.8: Added 'max_num_fields' parameter.

     Changed in version 3.10: Added 'separator' parameter with the
     default value of ‘&’.  Python versions earlier than Python 3.10
     allowed using both ‘;’ and ‘&’ as query parameter separator.  This
     has been changed to allow only a single separator key, with ‘&’ as
     the default separator.

 -- Function: urllib.parse.urlunsplit (parts)

     Construct a URL from a tuple as returned by ‘urlsplit()’.  The
     'parts' argument can be any five-item iterable.  This may result in
     a slightly different, but equivalent URL, if the URL that was
     parsed originally had unnecessary delimiters (for example, a ‘?’
     with an empty query; the RFC states that these are equivalent).

 -- Function: urllib.parse.urlparse (urlstring, scheme=None,
          allow_fragments=True)

     This is similar to *note urlsplit(): d67, but additionally splits
     the 'path' component on 'path' and 'params'.  This function returns
     a 6-item *note named tuple: 651. *note ParseResult: 3c74. or *note
     ParseResultBytes: 3c75.  Its items are the same as for the
     ‘urlsplit()’ result, except that 'params' is inserted at index 3,
     between 'path' and 'query'.

     This function is based on obsoleted RFC 1738(5) and RFC 1808(6),
     which listed 'params' as the main URL component.  The more recent
     URL syntax allows parameters to be applied to each segment of the
     'path' portion of the URL (see RFC 3986(7)).  *note urlsplit():
     d67. should generally be used instead of ‘urlparse()’.  A separate
     function is needed to separate the path segments and parameters.

 -- Function: urllib.parse.urlunparse (parts)

     Combine the elements of a tuple as returned by *note urlparse():
     30d. into a complete URL as a string.  The 'parts' argument can be
     any six-item iterable.  This may result in a slightly different,
     but equivalent URL, if the URL that was parsed originally had
     unnecessary delimiters (for example, a ?  with an empty query; the
     RFC states that these are equivalent).

 -- Function: urllib.parse.urljoin (base, url, allow_fragments=True)

     Construct a full (“absolute”) URL by combining a “base URL”
     ('base') with another URL ('url').  Informally, this uses
     components of the base URL, in particular the addressing scheme,
     the network location and (part of) the path, to provide missing
     components in the relative URL. For example:

          >>> from urllib.parse import urljoin
          >>> urljoin('http://www.cwi.nl/%7Eguido/Python.html', 'FAQ.html')
          'http://www.cwi.nl/%7Eguido/FAQ.html'

     The 'allow_fragments' argument has the same meaning and default as
     for *note urlsplit(): d67.

          Note: If 'url' is an absolute URL (that is, it starts with
          ‘//’ or ‘scheme://’), the 'url'’s hostname and/or scheme will
          be present in the result.  For example:

               >>> urljoin('http://www.cwi.nl/%7Eguido/Python.html',
               ...         '//www.python.org/%7Eguido')
               'http://www.python.org/%7Eguido'

          If you do not want that behavior, preprocess the 'url' with
          *note urlsplit(): d67. and *note urlunsplit(): 16de, removing
          possible 'scheme' and 'netloc' parts.

          Warning: Because an absolute URL may be passed as the ‘url’
          parameter, it is generally 'not secure' to use ‘urljoin’ with
          an attacker-controlled ‘url’.  For example in,
          ‘urljoin("https://website.com/users/", username)’, if
          ‘username’ can contain an absolute URL, the result of
          ‘urljoin’ will be the absolute URL.

     Changed in version 3.5: Behavior updated to match the semantics
     defined in RFC 3986(8).

 -- Function: urllib.parse.urldefrag (url)

     If 'url' contains a fragment identifier, return a modified version
     of 'url' with no fragment identifier, and the fragment identifier
     as a separate string.  If there is no fragment identifier in 'url',
     return 'url' unmodified and an empty string.

     The return value is a *note named tuple: 651, its items can be
     accessed by index or as named attributes:

     Attribute              Index       Value                         Value if not present
                                                                      
     --------------------------------------------------------------------------------------------
                                                                      
     ‘url’                  0           URL with no fragment          empty string
                                                                      
                                                                      
     ‘fragment’             1           Fragment identifier           empty string
                                                                      

     See section *note Structured Parse Results: 3c72. for more
     information on the result object.

     Changed in version 3.2: Result is a structured object rather than a
     simple 2-tuple.

 -- Function: urllib.parse.unwrap (url)

     Extract the url from a wrapped URL (that is, a string formatted as
     ‘<URL:scheme://host/path>’, ‘<scheme://host/path>’,
     ‘URL:scheme://host/path’ or ‘scheme://host/path’).  If 'url' is not
     a wrapped URL, it is returned without changes.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc1808.html

   (2) https://url.spec.whatwg.org/#concept-basic-url-parser

   (3) https://datatracker.ietf.org/doc/html/rfc3986.html

   (4) https://datatracker.ietf.org/doc/html/rfc3986.html

   (5) https://datatracker.ietf.org/doc/html/rfc1738.html

   (6) https://datatracker.ietf.org/doc/html/rfc1808.html

   (7) https://datatracker.ietf.org/doc/html/rfc3986.html

   (8) https://datatracker.ietf.org/doc/html/rfc3986.html


File: python.info,  Node: URL parsing security,  Next: Parsing ASCII Encoded Bytes,  Prev: URL Parsing,  Up: urllib parse — Parse URLs into components

5.22.6.2 URL parsing security
.............................

The *note urlsplit(): d67. and *note urlparse(): 30d. APIs do not
perform 'validation' of inputs.  They may not raise errors on inputs
that other applications consider invalid.  They may also succeed on some
inputs that might not be considered URLs elsewhere.  Their purpose is
for practical functionality rather than purity.

Instead of raising an exception on unusual input, they may instead
return some component parts as empty strings.  Or components may contain
more than perhaps they should.

We recommend that users of these APIs where the values may be used
anywhere with security implications code defensively.  Do some
verification within your code before trusting a returned component part.
Does that ‘scheme’ make sense?  Is that a sensible ‘path’?  Is there
anything strange about that ‘hostname’?  etc.

What constitutes a URL is not universally well defined.  Different
applications have different needs and desired constraints.  For instance
the living WHATWG spec(1) describes what user facing web clients such as
a web browser require.  While RFC 3986(2) is more general.  These
functions incorporate some aspects of both, but cannot be claimed
compliant with either.  The APIs and existing user code with
expectations on specific behaviors predate both standards leading us to
be very cautious about making API behavior changes.

   ---------- Footnotes ----------

   (1) https://url.spec.whatwg.org/#concept-basic-url-parser

   (2) https://datatracker.ietf.org/doc/html/rfc3986.html


File: python.info,  Node: Parsing ASCII Encoded Bytes,  Next: Structured Parse Results,  Prev: URL parsing security,  Up: urllib parse — Parse URLs into components

5.22.6.3 Parsing ASCII Encoded Bytes
....................................

The URL parsing functions were originally designed to operate on
character strings only.  In practice, it is useful to be able to
manipulate properly quoted and encoded URLs as sequences of ASCII bytes.
Accordingly, the URL parsing functions in this module all operate on
*note bytes: 1c2. and *note bytearray: 2ea. objects in addition to *note
str: 44f. objects.

If *note str: 44f. data is passed in, the result will also contain only
‘str’ data.  If *note bytes: 1c2. or *note bytearray: 2ea. data is
passed in, the result will contain only ‘bytes’ data.

Attempting to mix *note str: 44f. data with *note bytes: 1c2. or *note
bytearray: 2ea. in a single function call will result in a *note
TypeError: 2c3. being raised, while attempting to pass in non-ASCII byte
values will trigger *note UnicodeDecodeError: a20.

To support easier conversion of result objects between *note str: 44f.
and *note bytes: 1c2, all return values from URL parsing functions
provide either an ‘encode()’ method (when the result contains ‘str’
data) or a ‘decode()’ method (when the result contains ‘bytes’ data).
The signatures of these methods match those of the corresponding ‘str’
and ‘bytes’ methods (except that the default encoding is ‘'ascii'’
rather than ‘'utf-8'’).  Each produces a value of a corresponding type
that contains either ‘bytes’ data (for ‘encode()’ methods) or ‘str’ data
(for ‘decode()’ methods).

Applications that need to operate on potentially improperly quoted URLs
that may contain non-ASCII data will need to do their own decoding from
bytes to characters before invoking the URL parsing methods.

The behaviour described in this section applies only to the URL parsing
functions.  The URL quoting functions use their own rules when producing
or consuming byte sequences as detailed in the documentation of the
individual URL quoting functions.

Changed in version 3.2: URL parsing functions now accept ASCII encoded
byte sequences


File: python.info,  Node: Structured Parse Results,  Next: URL Quoting,  Prev: Parsing ASCII Encoded Bytes,  Up: urllib parse — Parse URLs into components

5.22.6.4 Structured Parse Results
.................................

The result objects from the *note urlsplit(): d67, *note urlparse():
30d. and *note urldefrag(): 128e. functions are subclasses of the *note
tuple: 373. type.  These subclasses add the attributes listed in the
documentation for those functions, the encoding and decoding support
described in the previous section, as well as an additional method:

 -- Method: urllib.parse.SplitResult.geturl ()

     Return the re-combined version of the original URL as a string.
     This may differ from the original URL in that the scheme may be
     normalized to lower case and empty components may be dropped.
     Specifically, empty parameters, queries, and fragment identifiers
     will be removed.

     For *note urldefrag(): 128e. results, only empty fragment
     identifiers will be removed.  For *note urlsplit(): d67. and *note
     urlparse(): 30d. results, all noted changes will be made to the URL
     returned by this method.

     The result of this method remains unchanged if passed back through
     the original parsing function:

          >>> from urllib.parse import urlsplit
          >>> url = 'HTTP://www.Python.org/doc/#'
          >>> r1 = urlsplit(url)
          >>> r1.geturl()
          'http://www.Python.org/doc/'
          >>> r2 = urlsplit(r1.geturl())
          >>> r2.geturl()
          'http://www.Python.org/doc/'

The following classes provide the implementations of the structured
parse results when operating on *note str: 44f. objects:

 -- Class: urllib.parse.DefragResult (url, fragment)

     Concrete class for *note urldefrag(): 128e. results containing
     *note str: 44f. data.  The ‘encode()’ method returns a *note
     DefragResultBytes: 3c7c. instance.

     Added in version 3.2.

 -- Class: urllib.parse.ParseResult (scheme, netloc, path, params,
          query, fragment)

     Concrete class for *note urlparse(): 30d. results containing *note
     str: 44f. data.  The ‘encode()’ method returns a *note
     ParseResultBytes: 3c75. instance.

 -- Class: urllib.parse.SplitResult (scheme, netloc, path, query,
          fragment)

     Concrete class for *note urlsplit(): d67. results containing *note
     str: 44f. data.  The ‘encode()’ method returns a *note
     SplitResultBytes: 3c71. instance.

The following classes provide the implementations of the parse results
when operating on *note bytes: 1c2. or *note bytearray: 2ea. objects:

 -- Class: urllib.parse.DefragResultBytes (url, fragment)

     Concrete class for *note urldefrag(): 128e. results containing
     *note bytes: 1c2. data.  The ‘decode()’ method returns a *note
     DefragResult: 3c7b. instance.

     Added in version 3.2.

 -- Class: urllib.parse.ParseResultBytes (scheme, netloc, path, params,
          query, fragment)

     Concrete class for *note urlparse(): 30d. results containing *note
     bytes: 1c2. data.  The ‘decode()’ method returns a *note
     ParseResult: 3c74. instance.

     Added in version 3.2.

 -- Class: urllib.parse.SplitResultBytes (scheme, netloc, path, query,
          fragment)

     Concrete class for *note urlsplit(): d67. results containing *note
     bytes: 1c2. data.  The ‘decode()’ method returns a *note
     SplitResult: 3c70. instance.

     Added in version 3.2.


File: python.info,  Node: URL Quoting,  Prev: Structured Parse Results,  Up: urllib parse — Parse URLs into components

5.22.6.5 URL Quoting
....................

The URL quoting functions focus on taking program data and making it
safe for use as URL components by quoting special characters and
appropriately encoding non-ASCII text.  They also support reversing
these operations to recreate the original data from the contents of a
URL component if that task isn’t already covered by the URL parsing
functions above.

 -- Function: urllib.parse.quote (string, safe='/', encoding=None,
          errors=None)

     Replace special characters in 'string' using the ‘%XX’ escape.
     Letters, digits, and the characters ‘'_.-~'’ are never quoted.  By
     default, this function is intended for quoting the path section of
     a URL. The optional 'safe' parameter specifies additional ASCII
     characters that should not be quoted — its default value is ‘'/'’.

     'string' may be either a *note str: 44f. or a *note bytes: 1c2.
     object.

     Changed in version 3.7: Moved from RFC 2396(1) to RFC 3986(2) for
     quoting URL strings.  “~” is now included in the set of unreserved
     characters.

     The optional 'encoding' and 'errors' parameters specify how to deal
     with non-ASCII characters, as accepted by the *note str.encode():
     8de. method.  'encoding' defaults to ‘'utf-8'’.  'errors' defaults
     to ‘'strict'’, meaning unsupported characters raise a *note
     UnicodeEncodeError: 67a.  'encoding' and 'errors' must not be
     supplied if 'string' is a *note bytes: 1c2, or a *note TypeError:
     2c3. is raised.

     Note that ‘quote(string, safe, encoding, errors)’ is equivalent to
     ‘quote_from_bytes(string.encode(encoding, errors), safe)’.

     Example: ‘quote('/El Niño/')’ yields ‘'/El%20Ni%C3%B1o/'’.

 -- Function: urllib.parse.quote_plus (string, safe='', encoding=None,
          errors=None)

     Like *note quote(): bc1, but also replace spaces with plus signs,
     as required for quoting HTML form values when building up a query
     string to go into a URL. Plus signs in the original string are
     escaped unless they are included in 'safe'.  It also does not have
     'safe' default to ‘'/'’.

     Example: ‘quote_plus('/El Niño/')’ yields ‘'%2FEl+Ni%C3%B1o%2F'’.

 -- Function: urllib.parse.quote_from_bytes (bytes, safe='/')

     Like *note quote(): bc1, but accepts a *note bytes: 1c2. object
     rather than a *note str: 44f, and does not perform string-to-bytes
     encoding.

     Example: ‘quote_from_bytes(b'a&\xef')’ yields ‘'a%26%EF'’.

 -- Function: urllib.parse.unquote (string, encoding='utf-8',
          errors='replace')

     Replace ‘%XX’ escapes with their single-character equivalent.  The
     optional 'encoding' and 'errors' parameters specify how to decode
     percent-encoded sequences into Unicode characters, as accepted by
     the *note bytes.decode(): 8df. method.

     'string' may be either a *note str: 44f. or a *note bytes: 1c2.
     object.

     'encoding' defaults to ‘'utf-8'’.  'errors' defaults to
     ‘'replace'’, meaning invalid sequences are replaced by a
     placeholder character.

     Example: ‘unquote('/El%20Ni%C3%B1o/')’ yields ‘'/El Niño/'’.

     Changed in version 3.9: 'string' parameter supports bytes and str
     objects (previously only str).

 -- Function: urllib.parse.unquote_plus (string, encoding='utf-8',
          errors='replace')

     Like *note unquote(): 189e, but also replace plus signs with
     spaces, as required for unquoting HTML form values.

     'string' must be a *note str: 44f.

     Example: ‘unquote_plus('/El+Ni%C3%B1o/')’ yields ‘'/El Niño/'’.

 -- Function: urllib.parse.unquote_to_bytes (string)

     Replace ‘%XX’ escapes with their single-octet equivalent, and
     return a *note bytes: 1c2. object.

     'string' may be either a *note str: 44f. or a *note bytes: 1c2.
     object.

     If it is a *note str: 44f, unescaped non-ASCII characters in
     'string' are encoded into UTF-8 bytes.

     Example: ‘unquote_to_bytes('a%26%EF')’ yields ‘b'a&\xef'’.

 -- Function: urllib.parse.urlencode (query, doseq=False, safe='',
          encoding=None, errors=None, quote_via=quote_plus)

     Convert a mapping object or a sequence of two-element tuples, which
     may contain *note str: 44f. or *note bytes: 1c2. objects, to a
     percent-encoded ASCII text string.  If the resultant string is to
     be used as a 'data' for POST operation with the *note urlopen():
     293. function, then it should be encoded to bytes, otherwise it
     would result in a *note TypeError: 2c3.

     The resulting string is a series of ‘key=value’ pairs separated by
     ‘'&'’ characters, where both 'key' and 'value' are quoted using the
     'quote_via' function.  By default, *note quote_plus(): 128f. is
     used to quote the values, which means spaces are quoted as a ‘'+'’
     character and ‘/’ characters are encoded as ‘%2F’, which follows
     the standard for GET requests
     (‘application/x-www-form-urlencoded’).  An alternate function that
     can be passed as 'quote_via' is *note quote(): bc1, which will
     encode spaces as ‘%20’ and not encode ‘/’ characters.  For maximum
     control of what is quoted, use ‘quote’ and specify a value for
     'safe'.

     When a sequence of two-element tuples is used as the 'query'
     argument, the first element of each tuple is a key and the second
     is a value.  The value element in itself can be a sequence and in
     that case, if the optional parameter 'doseq' evaluates to ‘True’,
     individual ‘key=value’ pairs separated by ‘'&'’ are generated for
     each element of the value sequence for the key.  The order of
     parameters in the encoded string will match the order of parameter
     tuples in the sequence.

     The 'safe', 'encoding', and 'errors' parameters are passed down to
     'quote_via' (the 'encoding' and 'errors' parameters are only passed
     when a query element is a *note str: 44f.).

     To reverse this encoding process, *note parse_qs(): 27a. and *note
     parse_qsl(): 279. are provided in this module to parse query
     strings into Python data structures.

     Refer to *note urllib examples: 3c5b. to find out how the *note
     urllib.parse.urlencode(): ec9. method can be used for generating
     the query string of a URL or data for a POST request.

     Changed in version 3.2: 'query' supports bytes and string objects.

     Changed in version 3.5: Added the 'quote_via' parameter.

See also
........

WHATWG(3) - URL Living standard

     Working Group for the URL Standard that defines URLs, domains, IP
     addresses, the application/x-www-form-urlencoded format, and their
     API.

RFC 3986(4) - Uniform Resource Identifiers

     This is the current standard (STD66).  Any changes to urllib.parse
     module should conform to this.  Certain deviations could be
     observed, which are mostly for backward compatibility purposes and
     for certain de-facto parsing requirements as commonly observed in
     major browsers.

RFC 2732(5) - Format for Literal IPv6 Addresses in URL’s.

     This specifies the parsing requirements of IPv6 URLs.

RFC 2396(6) - Uniform Resource Identifiers (URI): Generic Syntax

     Document describing the generic syntactic requirements for both
     Uniform Resource Names (URNs) and Uniform Resource Locators (URLs).

RFC 2368(7) - The mailto URL scheme.

     Parsing requirements for mailto URL schemes.

RFC 1808(8) - Relative Uniform Resource Locators

     This Request For Comments includes the rules for joining an
     absolute and a relative URL, including a fair number of “Abnormal
     Examples” which govern the treatment of border cases.

RFC 1738(9) - Uniform Resource Locators (URL)

     This specifies the formal syntax and semantics of absolute URLs.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2396.html

   (2) https://datatracker.ietf.org/doc/html/rfc3986.html

   (3) https://url.spec.whatwg.org/

   (4) https://datatracker.ietf.org/doc/html/rfc3986.html

   (5) https://datatracker.ietf.org/doc/html/rfc2732.html

   (6) https://datatracker.ietf.org/doc/html/rfc2396.html

   (7) https://datatracker.ietf.org/doc/html/rfc2368.html

   (8) https://datatracker.ietf.org/doc/html/rfc1808.html

   (9) https://datatracker.ietf.org/doc/html/rfc1738.html


File: python.info,  Node: urllib error — Exception classes raised by urllib request,  Next: urllib robotparser — Parser for robots txt,  Prev: urllib parse — Parse URLs into components,  Up: Internet Protocols and Support

5.22.7 ‘urllib.error’ — Exception classes raised by urllib.request
------------------------------------------------------------------

'Source code:' Lib/urllib/error.py(1)

__________________________________________________________________

The ‘urllib.error’ module defines the exception classes for exceptions
raised by *note urllib.request: 10b.  The base exception class is *note
URLError: 3be6.

The following exceptions are raised by ‘urllib.error’ as appropriate:

 -- Exception: urllib.error.URLError

     The handlers raise this exception (or derived exceptions) when they
     run into a problem.  It is a subclass of *note OSError: 41a.

      -- Attribute: reason

          The reason for this error.  It can be a message string or
          another exception instance.

     Changed in version 3.3: ‘URLError’ used to be a subtype of *note
     IOError: 1090, which is now an alias of *note OSError: 41a.

 -- Exception: urllib.error.HTTPError (url, code, msg, hdrs, fp)

     Though being an exception (a subclass of *note URLError: 3be6.), an
     ‘HTTPError’ can also function as a non-exceptional file-like return
     value (the same thing that *note urlopen(): 293. returns).  This is
     useful when handling exotic HTTP errors, such as requests for
     authentication.

      -- Attribute: url

          Contains the request URL. An alias for 'filename' attribute.

      -- Attribute: code

          An HTTP status code as defined in RFC 2616(2).  This numeric
          value corresponds to a value found in the dictionary of codes
          as found in *note
          http.server.BaseHTTPRequestHandler.responses: 3c85.

      -- Attribute: reason

          This is usually a string explaining the reason for this error.
          An alias for 'msg' attribute.

      -- Attribute: headers

          The HTTP response headers for the HTTP request that caused the
          ‘HTTPError’.  An alias for 'hdrs' attribute.

          Added in version 3.4.

      -- Attribute: fp

          A file-like object where the HTTP error body can be read from.

 -- Exception: urllib.error.ContentTooShortError (msg, content)

     This exception is raised when the *note urlretrieve(): 3c5d.
     function detects that the amount of the downloaded data is less
     than the expected amount (given by the 'Content-Length' header).

      -- Attribute: content

          The downloaded (and supposedly truncated) data.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/urllib/error.py

   (2) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: urllib robotparser — Parser for robots txt,  Next: http — HTTP modules,  Prev: urllib error — Exception classes raised by urllib request,  Up: Internet Protocols and Support

5.22.8 ‘urllib.robotparser’ — Parser for robots.txt
---------------------------------------------------

'Source code:' Lib/urllib/robotparser.py(1)

__________________________________________________________________

This module provides a single class, *note RobotFileParser: d25, which
answers questions about whether or not a particular user agent can fetch
a URL on the website that published the ‘robots.txt’ file.  For more
details on the structure of ‘robots.txt’ files, see
‘http://www.robotstxt.org/orig.html’.

 -- Class: urllib.robotparser.RobotFileParser (url='')

     This class provides methods to read, parse and answer questions
     about the ‘robots.txt’ file at 'url'.

      -- Method: set_url (url)

          Sets the URL referring to a ‘robots.txt’ file.

      -- Method: read ()

          Reads the ‘robots.txt’ URL and feeds it to the parser.

      -- Method: parse (lines)

          Parses the lines argument.

      -- Method: can_fetch (useragent, url)

          Returns ‘True’ if the 'useragent' is allowed to fetch the
          'url' according to the rules contained in the parsed
          ‘robots.txt’ file.

      -- Method: mtime ()

          Returns the time the ‘robots.txt’ file was last fetched.  This
          is useful for long-running web spiders that need to check for
          new ‘robots.txt’ files periodically.

      -- Method: modified ()

          Sets the time the ‘robots.txt’ file was last fetched to the
          current time.

      -- Method: crawl_delay (useragent)

          Returns the value of the ‘Crawl-delay’ parameter from
          ‘robots.txt’ for the 'useragent' in question.  If there is no
          such parameter or it doesn’t apply to the 'useragent'
          specified or the ‘robots.txt’ entry for this parameter has
          invalid syntax, return ‘None’.

          Added in version 3.6.

      -- Method: request_rate (useragent)

          Returns the contents of the ‘Request-rate’ parameter from
          ‘robots.txt’ as a *note named tuple: 651.
          ‘RequestRate(requests, seconds)’.  If there is no such
          parameter or it doesn’t apply to the 'useragent' specified or
          the ‘robots.txt’ entry for this parameter has invalid syntax,
          return ‘None’.

          Added in version 3.6.

      -- Method: site_maps ()

          Returns the contents of the ‘Sitemap’ parameter from
          ‘robots.txt’ in the form of a *note list(): 614.  If there is
          no such parameter or the ‘robots.txt’ entry for this parameter
          has invalid syntax, return ‘None’.

          Added in version 3.8.

The following example demonstrates basic use of the *note
RobotFileParser: d25. class:

     >>> import urllib.robotparser
     >>> rp = urllib.robotparser.RobotFileParser()
     >>> rp.set_url("http://www.pythontest.net/robots.txt")
     >>> rp.read()
     >>> rrate = rp.request_rate("*")
     >>> rrate.requests
     1
     >>> rrate.seconds
     1
     >>> rp.crawl_delay("*")
     6
     >>> rp.can_fetch("*", "http://www.pythontest.net/")
     True
     >>> rp.can_fetch("*", "http://www.pythontest.net/no-robots-here/")
     False

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/urllib/robotparser.py


File: python.info,  Node: http — HTTP modules,  Next: http client — HTTP protocol client,  Prev: urllib robotparser — Parser for robots txt,  Up: Internet Protocols and Support

5.22.9 ‘http’ — HTTP modules
----------------------------

'Source code:' Lib/http/__init__.py(1)

__________________________________________________________________

‘http’ is a package that collects several modules for working with the
HyperText Transfer Protocol:

   * *note http.client: 6f. is a low-level HTTP protocol client; for
     high-level URL opening use *note urllib.request: 10b.

   * *note http.server: 72. contains basic HTTP server classes based on
     *note socketserver: cd.

   * *note http.cookies: 71. has utilities for implementing state
     management with cookies

   * *note http.cookiejar: 70. provides persistence of cookies

The ‘http’ module also defines the following enums that help you work
with http related code:

 -- Class: http.HTTPStatus

     Added in version 3.5.

     A subclass of *note enum.IntEnum: d06. that defines a set of HTTP
     status codes, reason phrases and long descriptions written in
     English.

     Usage:

          >>> from http import HTTPStatus
          >>> HTTPStatus.OK
          HTTPStatus.OK
          >>> HTTPStatus.OK == 200
          True
          >>> HTTPStatus.OK.value
          200
          >>> HTTPStatus.OK.phrase
          'OK'
          >>> HTTPStatus.OK.description
          'Request fulfilled, document follows'
          >>> list(HTTPStatus)
          [HTTPStatus.CONTINUE, HTTPStatus.SWITCHING_PROTOCOLS, ...]

* Menu:

* HTTP status codes::
* HTTP status category::
* HTTP methods::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/http/__init__.py


File: python.info,  Node: HTTP status codes,  Next: HTTP status category,  Up: http — HTTP modules

5.22.9.1 HTTP status codes
..........................

Supported, IANA-registered status codes(1) available in *note
http.HTTPStatus: 909. are:

Code        Enum Name                               Details
                                                    
----------------------------------------------------------------------------------------------------------------------------------------
                                                    
‘100’       ‘CONTINUE’                              HTTP Semantics RFC 9110(2), Section 15.2.1
                                                    
                                                    
‘101’       ‘SWITCHING_PROTOCOLS’                   HTTP Semantics RFC 9110(3), Section 15.2.2
                                                    
                                                    
‘102’       ‘PROCESSING’                            WebDAV RFC 2518(4), Section 10.1
                                                    
                                                    
‘103’       ‘EARLY_HINTS’                           An HTTP Status Code for Indicating Hints RFC 8297(5)
                                                    
                                                    
‘200’       ‘OK’                                    HTTP Semantics RFC 9110(6), Section 15.3.1
                                                    
                                                    
‘201’       ‘CREATED’                               HTTP Semantics RFC 9110(7), Section 15.3.2
                                                    
                                                    
‘202’       ‘ACCEPTED’                              HTTP Semantics RFC 9110(8), Section 15.3.3
                                                    
                                                    
‘203’       ‘NON_AUTHORITATIVE_INFORMATION’         HTTP Semantics RFC 9110(9), Section 15.3.4
                                                    
                                                    
‘204’       ‘NO_CONTENT’                            HTTP Semantics RFC 9110(10), Section 15.3.5
                                                    
                                                    
‘205’       ‘RESET_CONTENT’                         HTTP Semantics RFC 9110(11), Section 15.3.6
                                                    
                                                    
‘206’       ‘PARTIAL_CONTENT’                       HTTP Semantics RFC 9110(12), Section 15.3.7
                                                    
                                                    
‘207’       ‘MULTI_STATUS’                          WebDAV RFC 4918(13), Section 11.1
                                                    
                                                    
‘208’       ‘ALREADY_REPORTED’                      WebDAV Binding Extensions RFC 5842(14), Section 7.1 (Experimental)
                                                    
                                                    
‘226’       ‘IM_USED’                               Delta Encoding in HTTP RFC 3229(15), Section 10.4.1
                                                    
                                                    
‘300’       ‘MULTIPLE_CHOICES’                      HTTP Semantics RFC 9110(16), Section 15.4.1
                                                    
                                                    
‘301’       ‘MOVED_PERMANENTLY’                     HTTP Semantics RFC 9110(17), Section 15.4.2
                                                    
                                                    
‘302’       ‘FOUND’                                 HTTP Semantics RFC 9110(18), Section 15.4.3
                                                    
                                                    
‘303’       ‘SEE_OTHER’                             HTTP Semantics RFC 9110(19), Section 15.4.4
                                                    
                                                    
‘304’       ‘NOT_MODIFIED’                          HTTP Semantics RFC 9110(20), Section 15.4.5
                                                    
                                                    
‘305’       ‘USE_PROXY’                             HTTP Semantics RFC 9110(21), Section 15.4.6
                                                    
                                                    
‘307’       ‘TEMPORARY_REDIRECT’                    HTTP Semantics RFC 9110(22), Section 15.4.8
                                                    
                                                    
‘308’       ‘PERMANENT_REDIRECT’                    HTTP Semantics RFC 9110(23), Section 15.4.9
                                                    
                                                    
‘400’       ‘BAD_REQUEST’                           HTTP Semantics RFC 9110(24), Section 15.5.1
                                                    
                                                    
‘401’       ‘UNAUTHORIZED’                          HTTP Semantics RFC 9110(25), Section 15.5.2
                                                    
                                                    
‘402’       ‘PAYMENT_REQUIRED’                      HTTP Semantics RFC 9110(26), Section 15.5.3
                                                    
                                                    
‘403’       ‘FORBIDDEN’                             HTTP Semantics RFC 9110(27), Section 15.5.4
                                                    
                                                    
‘404’       ‘NOT_FOUND’                             HTTP Semantics RFC 9110(28), Section 15.5.5
                                                    
                                                    
‘405’       ‘METHOD_NOT_ALLOWED’                    HTTP Semantics RFC 9110(29), Section 15.5.6
                                                    
                                                    
‘406’       ‘NOT_ACCEPTABLE’                        HTTP Semantics RFC 9110(30), Section 15.5.7
                                                    
                                                    
‘407’       ‘PROXY_AUTHENTICATION_REQUIRED’         HTTP Semantics RFC 9110(31), Section 15.5.8
                                                    
                                                    
‘408’       ‘REQUEST_TIMEOUT’                       HTTP Semantics RFC 9110(32), Section 15.5.9
                                                    
                                                    
‘409’       ‘CONFLICT’                              HTTP Semantics RFC 9110(33), Section 15.5.10
                                                    
                                                    
‘410’       ‘GONE’                                  HTTP Semantics RFC 9110(34), Section 15.5.11
                                                    
                                                    
‘411’       ‘LENGTH_REQUIRED’                       HTTP Semantics RFC 9110(35), Section 15.5.12
                                                    
                                                    
‘412’       ‘PRECONDITION_FAILED’                   HTTP Semantics RFC 9110(36), Section 15.5.13
                                                    
                                                    
‘413’       ‘CONTENT_TOO_LARGE’                     HTTP Semantics RFC 9110(37), Section 15.5.14
                                                    
                                                    
‘414’       ‘URI_TOO_LONG’                          HTTP Semantics RFC 9110(38), Section 15.5.15
                                                    
                                                    
‘415’       ‘UNSUPPORTED_MEDIA_TYPE’                HTTP Semantics RFC 9110(39), Section 15.5.16
                                                    
                                                    
‘416’       ‘RANGE_NOT_SATISFIABLE’                 HTTP Semantics RFC 9110(40), Section 15.5.17
                                                    
                                                    
‘417’       ‘EXPECTATION_FAILED’                    HTTP Semantics RFC 9110(41), Section 15.5.18
                                                    
                                                    
‘418’       ‘IM_A_TEAPOT’                           HTCPCP/1.0 RFC 2324(42), Section 2.3.2
                                                    
                                                    
‘421’       ‘MISDIRECTED_REQUEST’                   HTTP Semantics RFC 9110(43), Section 15.5.20
                                                    
                                                    
‘422’       ‘UNPROCESSABLE_CONTENT’                 HTTP Semantics RFC 9110(44), Section 15.5.21
                                                    
                                                    
‘423’       ‘LOCKED’                                WebDAV RFC 4918(45), Section 11.3
                                                    
                                                    
‘424’       ‘FAILED_DEPENDENCY’                     WebDAV RFC 4918(46), Section 11.4
                                                    
                                                    
‘425’       ‘TOO_EARLY’                             Using Early Data in HTTP RFC 8470(47)
                                                    
                                                    
‘426’       ‘UPGRADE_REQUIRED’                      HTTP Semantics RFC 9110(48), Section 15.5.22
                                                    
                                                    
‘428’       ‘PRECONDITION_REQUIRED’                 Additional HTTP Status Codes RFC 6585(49)
                                                    
                                                    
‘429’       ‘TOO_MANY_REQUESTS’                     Additional HTTP Status Codes RFC 6585(50)
                                                    
                                                    
‘431’       ‘REQUEST_HEADER_FIELDS_TOO_LARGE’       Additional HTTP Status Codes RFC 6585(51)
                                                    
                                                    
‘451’       ‘UNAVAILABLE_FOR_LEGAL_REASONS’         An HTTP Status Code to Report Legal Obstacles RFC 7725(52)
                                                    
                                                    
‘500’       ‘INTERNAL_SERVER_ERROR’                 HTTP Semantics RFC 9110(53), Section 15.6.1
                                                    
                                                    
‘501’       ‘NOT_IMPLEMENTED’                       HTTP Semantics RFC 9110(54), Section 15.6.2
                                                    
                                                    
‘502’       ‘BAD_GATEWAY’                           HTTP Semantics RFC 9110(55), Section 15.6.3
                                                    
                                                    
‘503’       ‘SERVICE_UNAVAILABLE’                   HTTP Semantics RFC 9110(56), Section 15.6.4
                                                    
                                                    
‘504’       ‘GATEWAY_TIMEOUT’                       HTTP Semantics RFC 9110(57), Section 15.6.5
                                                    
                                                    
‘505’       ‘HTTP_VERSION_NOT_SUPPORTED’            HTTP Semantics RFC 9110(58), Section 15.6.6
                                                    
                                                    
‘506’       ‘VARIANT_ALSO_NEGOTIATES’               Transparent Content Negotiation in HTTP RFC 2295(59), Section 8.1 (Experimental)
                                                    
                                                    
‘507’       ‘INSUFFICIENT_STORAGE’                  WebDAV RFC 4918(60), Section 11.5
                                                    
                                                    
‘508’       ‘LOOP_DETECTED’                         WebDAV Binding Extensions RFC 5842(61), Section 7.2 (Experimental)
                                                    
                                                    
‘510’       ‘NOT_EXTENDED’                          An HTTP Extension Framework RFC 2774(62), Section 7 (Experimental)
                                                    
                                                    
‘511’       ‘NETWORK_AUTHENTICATION_REQUIRED’       Additional HTTP Status Codes RFC 6585(63), Section 6
                                                    

In order to preserve backwards compatibility, enum values are also
present in the *note http.client: 6f. module in the form of constants.
The enum name is equal to the constant name (i.e.  ‘http.HTTPStatus.OK’
is also available as ‘http.client.OK’).

Changed in version 3.7: Added ‘421 MISDIRECTED_REQUEST’ status code.

Added in version 3.8: Added ‘451 UNAVAILABLE_FOR_LEGAL_REASONS’ status
code.

Added in version 3.9: Added ‘103 EARLY_HINTS’, ‘418 IM_A_TEAPOT’ and
‘425 TOO_EARLY’ status codes.

Changed in version 3.13: Implemented RFC9110 naming for status
constants.  Old constant names are preserved for backwards
compatibility: ‘413 REQUEST_ENTITY_TOO_LARGE’, ‘414
REQUEST_URI_TOO_LONG’, ‘416 REQUESTED_RANGE_NOT_SATISFIABLE’ and ‘422
UNPROCESSABLE_ENTITY’.

   ---------- Footnotes ----------

   (1) 
https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml

   (2) https://datatracker.ietf.org/doc/html/rfc9110.html

   (3) https://datatracker.ietf.org/doc/html/rfc9110.html

   (4) https://datatracker.ietf.org/doc/html/rfc2518.html

   (5) https://datatracker.ietf.org/doc/html/rfc8297.html

   (6) https://datatracker.ietf.org/doc/html/rfc9110.html

   (7) https://datatracker.ietf.org/doc/html/rfc9110.html

   (8) https://datatracker.ietf.org/doc/html/rfc9110.html

   (9) https://datatracker.ietf.org/doc/html/rfc9110.html

   (10) https://datatracker.ietf.org/doc/html/rfc9110.html

   (11) https://datatracker.ietf.org/doc/html/rfc9110.html

   (12) https://datatracker.ietf.org/doc/html/rfc9110.html

   (13) https://datatracker.ietf.org/doc/html/rfc4918.html

   (14) https://datatracker.ietf.org/doc/html/rfc5842.html

   (15) https://datatracker.ietf.org/doc/html/rfc3229.html

   (16) https://datatracker.ietf.org/doc/html/rfc9110.html

   (17) https://datatracker.ietf.org/doc/html/rfc9110.html

   (18) https://datatracker.ietf.org/doc/html/rfc9110.html

   (19) https://datatracker.ietf.org/doc/html/rfc9110.html

   (20) https://datatracker.ietf.org/doc/html/rfc9110.html

   (21) https://datatracker.ietf.org/doc/html/rfc9110.html

   (22) https://datatracker.ietf.org/doc/html/rfc9110.html

   (23) https://datatracker.ietf.org/doc/html/rfc9110.html

   (24) https://datatracker.ietf.org/doc/html/rfc9110.html

   (25) https://datatracker.ietf.org/doc/html/rfc9110.html

   (26) https://datatracker.ietf.org/doc/html/rfc9110.html

   (27) https://datatracker.ietf.org/doc/html/rfc9110.html

   (28) https://datatracker.ietf.org/doc/html/rfc9110.html

   (29) https://datatracker.ietf.org/doc/html/rfc9110.html

   (30) https://datatracker.ietf.org/doc/html/rfc9110.html

   (31) https://datatracker.ietf.org/doc/html/rfc9110.html

   (32) https://datatracker.ietf.org/doc/html/rfc9110.html

   (33) https://datatracker.ietf.org/doc/html/rfc9110.html

   (34) https://datatracker.ietf.org/doc/html/rfc9110.html

   (35) https://datatracker.ietf.org/doc/html/rfc9110.html

   (36) https://datatracker.ietf.org/doc/html/rfc9110.html

   (37) https://datatracker.ietf.org/doc/html/rfc9110.html

   (38) https://datatracker.ietf.org/doc/html/rfc9110.html

   (39) https://datatracker.ietf.org/doc/html/rfc9110.html

   (40) https://datatracker.ietf.org/doc/html/rfc9110.html

   (41) https://datatracker.ietf.org/doc/html/rfc9110.html

   (42) https://datatracker.ietf.org/doc/html/rfc2324.html

   (43) https://datatracker.ietf.org/doc/html/rfc9110.html

   (44) https://datatracker.ietf.org/doc/html/rfc9110.html

   (45) https://datatracker.ietf.org/doc/html/rfc4918.html

   (46) https://datatracker.ietf.org/doc/html/rfc4918.html

   (47) https://datatracker.ietf.org/doc/html/rfc8470.html

   (48) https://datatracker.ietf.org/doc/html/rfc9110.html

   (49) https://datatracker.ietf.org/doc/html/rfc6585.html

   (50) https://datatracker.ietf.org/doc/html/rfc6585.html

   (51) https://datatracker.ietf.org/doc/html/rfc6585.html

   (52) https://datatracker.ietf.org/doc/html/rfc7725.html

   (53) https://datatracker.ietf.org/doc/html/rfc9110.html

   (54) https://datatracker.ietf.org/doc/html/rfc9110.html

   (55) https://datatracker.ietf.org/doc/html/rfc9110.html

   (56) https://datatracker.ietf.org/doc/html/rfc9110.html

   (57) https://datatracker.ietf.org/doc/html/rfc9110.html

   (58) https://datatracker.ietf.org/doc/html/rfc9110.html

   (59) https://datatracker.ietf.org/doc/html/rfc2295.html

   (60) https://datatracker.ietf.org/doc/html/rfc4918.html

   (61) https://datatracker.ietf.org/doc/html/rfc5842.html

   (62) https://datatracker.ietf.org/doc/html/rfc2774.html

   (63) https://datatracker.ietf.org/doc/html/rfc6585.html


File: python.info,  Node: HTTP status category,  Next: HTTP methods,  Prev: HTTP status codes,  Up: http — HTTP modules

5.22.9.2 HTTP status category
.............................

Added in version 3.12.

The enum values have several properties to indicate the HTTP status
category:

Property                 Indicates that               Details
                                                      
-------------------------------------------------------------------------------------------------
                                                      
‘is_informational’       ‘100 <= status <= 199’       HTTP Semantics RFC 9110(1), Section 15
                                                      
                                                      
‘is_success’             ‘200 <= status <= 299’       HTTP Semantics RFC 9110(2), Section 15
                                                      
                                                      
‘is_redirection’         ‘300 <= status <= 399’       HTTP Semantics RFC 9110(3), Section 15
                                                      
                                                      
‘is_client_error’        ‘400 <= status <= 499’       HTTP Semantics RFC 9110(4), Section 15
                                                      
                                                      
‘is_server_error’        ‘500 <= status <= 599’       HTTP Semantics RFC 9110(5), Section 15
                                                      

     Usage:

          >>> from http import HTTPStatus
          >>> HTTPStatus.OK.is_success
          True
          >>> HTTPStatus.OK.is_client_error
          False

 -- Class: http.HTTPMethod

     Added in version 3.11.

     A subclass of *note enum.StrEnum: 61d. that defines a set of HTTP
     methods and descriptions written in English.

     Usage:

          >>> from http import HTTPMethod
          >>>
          >>> HTTPMethod.GET
          <HTTPMethod.GET>
          >>> HTTPMethod.GET == 'GET'
          True
          >>> HTTPMethod.GET.value
          'GET'
          >>> HTTPMethod.GET.description
          'Retrieve the target.'
          >>> list(HTTPMethod)
          [<HTTPMethod.CONNECT>,
           <HTTPMethod.DELETE>,
           <HTTPMethod.GET>,
           <HTTPMethod.HEAD>,
           <HTTPMethod.OPTIONS>,
           <HTTPMethod.PATCH>,
           <HTTPMethod.POST>,
           <HTTPMethod.PUT>,
           <HTTPMethod.TRACE>]

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc9110.html

   (2) https://datatracker.ietf.org/doc/html/rfc9110.html

   (3) https://datatracker.ietf.org/doc/html/rfc9110.html

   (4) https://datatracker.ietf.org/doc/html/rfc9110.html

   (5) https://datatracker.ietf.org/doc/html/rfc9110.html


File: python.info,  Node: HTTP methods,  Prev: HTTP status category,  Up: http — HTTP modules

5.22.9.3 HTTP methods
.....................

Supported, IANA-registered methods(1) available in *note
http.HTTPMethod: 3c99. are:

Method          Enum Name                               Details
                                                        
-------------------------------------------------------------------------------------------------------------------------------
                                                        
‘GET’           ‘GET’                                   HTTP Semantics RFC 9110(2), Section 9.3.1
                                                        
                                                        
‘HEAD’          ‘HEAD’                                  HTTP Semantics RFC 9110(3), Section 9.3.2
                                                        
                                                        
‘POST’          ‘POST’                                  HTTP Semantics RFC 9110(4), Section 9.3.3
                                                        
                                                        
‘PUT’           ‘PUT’                                   HTTP Semantics RFC 9110(5), Section 9.3.4
                                                        
                                                        
‘DELETE’        ‘DELETE’                                HTTP Semantics RFC 9110(6), Section 9.3.5
                                                        
                                                        
‘CONNECT’       ‘CONNECT’                               HTTP Semantics RFC 9110(7), Section 9.3.6
                                                        
                                                        
‘OPTIONS’       ‘OPTIONS’                               HTTP Semantics RFC 9110(8), Section 9.3.7
                                                        
                                                        
‘TRACE’         ‘TRACE’                                 HTTP Semantics RFC 9110(9), Section 9.3.8
                                                        
                                                        
‘PATCH’         ‘PATCH’                                 HTTP/1.1 RFC 5789(10)
                                                        

   ---------- Footnotes ----------

   (1) https://www.iana.org/assignments/http-methods/http-methods.xhtml

   (2) https://datatracker.ietf.org/doc/html/rfc9110.html

   (3) https://datatracker.ietf.org/doc/html/rfc9110.html

   (4) https://datatracker.ietf.org/doc/html/rfc9110.html

   (5) https://datatracker.ietf.org/doc/html/rfc9110.html

   (6) https://datatracker.ietf.org/doc/html/rfc9110.html

   (7) https://datatracker.ietf.org/doc/html/rfc9110.html

   (8) https://datatracker.ietf.org/doc/html/rfc9110.html

   (9) https://datatracker.ietf.org/doc/html/rfc9110.html

   (10) https://datatracker.ietf.org/doc/html/rfc5789.html


File: python.info,  Node: http client — HTTP protocol client,  Next: ftplib — FTP protocol client,  Prev: http — HTTP modules,  Up: Internet Protocols and Support

5.22.10 ‘http.client’ — HTTP protocol client
--------------------------------------------

'Source code:' Lib/http/client.py(1)

__________________________________________________________________

This module defines classes that implement the client side of the HTTP
and HTTPS protocols.  It is normally not used directly — the module
*note urllib.request: 10b. uses it to handle URLs that use HTTP and
HTTPS.

See also
........

The Requests package(2) is recommended for a higher-level HTTP client
interface.

     Note: HTTPS support is only available if Python was compiled with
     SSL support (through the *note ssl: d0. module).

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The module provides the following classes:

 -- Class: http.client.HTTPConnection (host, port=None[, timeout],
          source_address=None, blocksize=8192)

     An ‘HTTPConnection’ instance represents one transaction with an
     HTTP server.  It should be instantiated by passing it a host and
     optional port number.  If no port number is passed, the port is
     extracted from the host string if it has the form ‘host:port’, else
     the default HTTP port (80) is used.  If the optional 'timeout'
     parameter is given, blocking operations (like connection attempts)
     will timeout after that many seconds (if it is not given, the
     global default timeout setting is used).  The optional
     'source_address' parameter may be a tuple of a (host, port) to use
     as the source address the HTTP connection is made from.  The
     optional 'blocksize' parameter sets the buffer size in bytes for
     sending a file-like message body.

     For example, the following calls all create instances that connect
     to the server at the same host and port:

          >>> h1 = http.client.HTTPConnection('www.python.org')
          >>> h2 = http.client.HTTPConnection('www.python.org:80')
          >>> h3 = http.client.HTTPConnection('www.python.org', 80)
          >>> h4 = http.client.HTTPConnection('www.python.org', 80, timeout=10)

     Changed in version 3.2: 'source_address' was added.

     Changed in version 3.4: The 'strict' parameter was removed.  HTTP
     0.9-style “Simple Responses” are no longer supported.

     Changed in version 3.7: 'blocksize' parameter was added.

 -- Class: http.client.HTTPSConnection (host, port=None, *[, timeout],
          source_address=None, context=None, blocksize=8192)

     A subclass of *note HTTPConnection: b59. that uses SSL for
     communication with secure servers.  Default port is ‘443’.  If
     'context' is specified, it must be a *note ssl.SSLContext: 294.
     instance describing the various SSL options.

     Please read *note Security considerations: 3564. for more
     information on best practices.

     Changed in version 3.2: 'source_address', 'context' and
     'check_hostname' were added.

     Changed in version 3.2: This class now supports HTTPS virtual hosts
     if possible (that is, if *note ssl.HAS_SNI: 36a6. is true).

     Changed in version 3.4: The 'strict' parameter was removed.  HTTP
     0.9-style “Simple Responses” are no longer supported.

     Changed in version 3.4.3: This class now performs all the necessary
     certificate and hostname checks by default.  To revert to the
     previous, unverified, behavior ‘ssl._create_unverified_context()’
     can be passed to the 'context' parameter.

     Changed in version 3.8: This class now enables TLS 1.3 *note
     ssl.SSLContext.post_handshake_auth: a3e. for the default 'context'
     or when 'cert_file' is passed with a custom 'context'.

     Changed in version 3.10: This class now sends an ALPN extension
     with protocol indicator ‘http/1.1’ when no 'context' is given.
     Custom 'context' should set ALPN protocols with *note
     set_alpn_protocols(): e98.

     Changed in version 3.12: The deprecated 'key_file', 'cert_file' and
     'check_hostname' parameters have been removed.

 -- Class: http.client.HTTPResponse (sock, debuglevel=0, method=None,
          url=None)

     Class whose instances are returned upon successful connection.  Not
     instantiated directly by user.

     Changed in version 3.4: The 'strict' parameter was removed.  HTTP
     0.9 style “Simple Responses” are no longer supported.

This module provides the following function:

 -- Function: http.client.parse_headers (fp)

     Parse the headers from a file pointer 'fp' representing a HTTP
     request/response.  The file has to be a *note BufferedIOBase: 697.
     reader (i.e.  not text) and must provide a valid RFC 5322(3) style
     header.

     This function returns an instance of *note http.client.HTTPMessage:
     3c9f. that holds the header fields, but no payload (the same as
     *note HTTPResponse.msg: 3ca0. and *note
     http.server.BaseHTTPRequestHandler.headers: 3ca1.).  After
     returning, the file pointer 'fp' is ready to read the HTTP body.

          Note: *note parse_headers(): 1bd9. does not parse the
          start-line of a HTTP message; it only parses the ‘Name: value’
          lines.  The file has to be ready to read these field lines, so
          the first line should already be consumed before calling the
          function.

The following exceptions are raised as appropriate:

 -- Exception: http.client.HTTPException

     The base class of the other exceptions in this module.  It is a
     subclass of *note Exception: 9e5.

 -- Exception: http.client.NotConnected

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.InvalidURL

     A subclass of *note HTTPException: 3ca2, raised if a port is given
     and is either non-numeric or empty.

 -- Exception: http.client.UnknownProtocol

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.UnknownTransferEncoding

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.UnimplementedFileMode

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.IncompleteRead

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.ImproperConnectionState

     A subclass of *note HTTPException: 3ca2.

 -- Exception: http.client.CannotSendRequest

     A subclass of *note ImproperConnectionState: 3ca9.

 -- Exception: http.client.CannotSendHeader

     A subclass of *note ImproperConnectionState: 3ca9.

 -- Exception: http.client.ResponseNotReady

     A subclass of *note ImproperConnectionState: 3ca9.

 -- Exception: http.client.BadStatusLine

     A subclass of *note HTTPException: 3ca2.  Raised if a server
     responds with a HTTP status code that we don’t understand.

 -- Exception: http.client.LineTooLong

     A subclass of *note HTTPException: 3ca2.  Raised if an excessively
     long line is received in the HTTP protocol from the server.

 -- Exception: http.client.RemoteDisconnected

     A subclass of *note ConnectionResetError: 109d. and *note
     BadStatusLine: 3cad.  Raised by *note HTTPConnection.getresponse():
     e3a. when the attempt to read the response results in no data read
     from the connection, indicating that the remote end has closed the
     connection.

     Added in version 3.5: Previously, *note BadStatusLine: 3cad.‘('')’
     was raised.

The constants defined in this module are:

 -- Data: http.client.HTTP_PORT

     The default port for the HTTP protocol (always ‘80’).

 -- Data: http.client.HTTPS_PORT

     The default port for the HTTPS protocol (always ‘443’).

 -- Data: http.client.responses

     This dictionary maps the HTTP 1.1 status codes to the W3C names.

     Example: ‘http.client.responses[http.client.NOT_FOUND]’ is ‘'Not
     Found'’.

See *note HTTP status codes: 3c96. for a list of HTTP status codes that
are available in this module as constants.

* Menu:

* HTTPConnection Objects::
* HTTPResponse Objects::
* Examples: Examples<27>.
* HTTPMessage Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/http/client.py

   (2) https://requests.readthedocs.io/en/latest/

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: HTTPConnection Objects,  Next: HTTPResponse Objects,  Up: http client — HTTP protocol client

5.22.10.1 HTTPConnection Objects
................................

*note HTTPConnection: b59. instances have the following methods:

 -- Method: HTTPConnection.request (method, url, body=None, headers={},
          *, encode_chunked=False)

     This will send a request to the server using the HTTP request
     method 'method' and the request URI 'url'.  The provided 'url' must
     be an absolute path to conform with RFC 2616 §5.1.2(1) (unless
     connecting to an HTTP proxy server or using the ‘OPTIONS’ or
     ‘CONNECT’ methods).

     If 'body' is specified, the specified data is sent after the
     headers are finished.  It may be a *note str: 44f, a *note
     bytes-like object: d55, an open *note file object: 1208, or an
     iterable of *note bytes: 1c2.  If 'body' is a string, it is encoded
     as ISO-8859-1, the default for HTTP. If it is a bytes-like object,
     the bytes are sent as is.  If it is a file object, the contents of
     the file is sent; this file object should support at least the
     ‘read()’ method.  If the file object is an instance of *note
     io.TextIOBase: 698, the data returned by the ‘read()’ method will
     be encoded as ISO-8859-1, otherwise the data returned by ‘read()’
     is sent as is.  If 'body' is an iterable, the elements of the
     iterable are sent as is until the iterable is exhausted.

     The 'headers' argument should be a mapping of extra HTTP headers to
     send with the request.  A Host header(2) must be provided to
     conform with RFC 2616 §5.1.2(3) (unless connecting to an HTTP proxy
     server or using the ‘OPTIONS’ or ‘CONNECT’ methods).

     If 'headers' contains neither Content-Length nor Transfer-Encoding,
     but there is a request body, one of those header fields will be
     added automatically.  If 'body' is ‘None’, the Content-Length
     header is set to ‘0’ for methods that expect a body (‘PUT’, ‘POST’,
     and ‘PATCH’).  If 'body' is a string or a bytes-like object that is
     not also a *note file: 1208, the Content-Length header is set to
     its length.  Any other type of 'body' (files and iterables in
     general) will be chunk-encoded, and the Transfer-Encoding header
     will automatically be set instead of Content-Length.

     The 'encode_chunked' argument is only relevant if Transfer-Encoding
     is specified in 'headers'.  If 'encode_chunked' is ‘False’, the
     HTTPConnection object assumes that all encoding is handled by the
     calling code.  If it is ‘True’, the body will be chunk-encoded.

     For example, to perform a ‘GET’ request to
     ‘https://docs.python.org/3/’:

          >>> import http.client
          >>> host = "docs.python.org"
          >>> conn = http.client.HTTPSConnection(host)
          >>> conn.request("GET", "/3/", headers={"Host": host})
          >>> response = conn.getresponse()
          >>> print(response.status, response.reason)
          200 OK

          Note: Chunked transfer encoding has been added to the HTTP
          protocol version 1.1.  Unless the HTTP server is known to
          handle HTTP 1.1, the caller must either specify the
          Content-Length, or must pass a *note str: 44f. or bytes-like
          object that is not also a file as the body representation.

          Note: Note that you must have read the whole response or call
          *note close(): 3cb4. if *note getresponse(): e3a. raised an
          non-*note ConnectionError: e3c. exception before you can send
          a new request to the server.

     Changed in version 3.2: 'body' can now be an iterable.

     Changed in version 3.6: If neither Content-Length nor
     Transfer-Encoding are set in 'headers', file and iterable 'body'
     objects are now chunk-encoded.  The 'encode_chunked' argument was
     added.  No attempt is made to determine the Content-Length for file
     objects.

 -- Method: HTTPConnection.getresponse ()

     Should be called after a request is sent to get the response from
     the server.  Returns an *note HTTPResponse: 1112. instance.

     Changed in version 3.5: If a *note ConnectionError: e3c. or
     subclass is raised, the *note HTTPConnection: b59. object will be
     ready to reconnect when a new request is sent.

     Note that this does not apply to *note OSError: 41a.s raised by the
     underlying socket.  Instead the caller is responsible to call *note
     close(): 3cb4. on the existing connection.

 -- Method: HTTPConnection.set_debuglevel (level)

     Set the debugging level.  The default debug level is ‘0’, meaning
     no debugging output is printed.  Any value greater than ‘0’ will
     cause all currently defined debug output to be printed to stdout.
     The ‘debuglevel’ is passed to any new *note HTTPResponse: 1112.
     objects that are created.

     Added in version 3.1.

 -- Method: HTTPConnection.set_tunnel (host, port=None, headers=None)

     Set the host and the port for HTTP Connect Tunnelling.  This allows
     running the connection through a proxy server.

     The 'host' and 'port' arguments specify the endpoint of the
     tunneled connection (i.e.  the address included in the CONNECT
     request, 'not' the address of the proxy server).

     The 'headers' argument should be a mapping of extra HTTP headers to
     send with the CONNECT request.

     As HTTP/1.1 is used for HTTP CONNECT tunnelling request, as per the
     RFC(4), a HTTP ‘Host:’ header must be provided, matching the
     authority-form of the request target provided as the destination
     for the CONNECT request.  If a HTTP ‘Host:’ header is not provided
     via the headers argument, one is generated and transmitted
     automatically.

     For example, to tunnel through a HTTPS proxy server running locally
     on port 8080, we would pass the address of the proxy to the *note
     HTTPSConnection: b5a. constructor, and the address of the host that
     we eventually want to reach to the ‘set_tunnel()’ method:

          >>> import http.client
          >>> conn = http.client.HTTPSConnection("localhost", 8080)
          >>> conn.set_tunnel("www.python.org")
          >>> conn.request("HEAD","/index.html")

     Added in version 3.2.

     Changed in version 3.12: HTTP CONNECT tunnelling requests use
     protocol HTTP/1.1, upgraded from protocol HTTP/1.0.  ‘Host:’ HTTP
     headers are mandatory for HTTP/1.1, so one will be automatically
     generated and transmitted if not provided in the headers argument.

 -- Method: HTTPConnection.get_proxy_response_headers ()

     Returns a dictionary with the headers of the response received from
     the proxy server to the CONNECT request.

     If the CONNECT request was not sent, the method returns ‘None’.

     Added in version 3.12.

 -- Method: HTTPConnection.connect ()

     Connect to the server specified when the object was created.  By
     default, this is called automatically when making a request if the
     client does not already have a connection.

     Raises an *note auditing event: 1a15. ‘http.client.connect’ with
     arguments ‘self’, ‘host’, ‘port’.

 -- Method: HTTPConnection.close ()

     Close the connection to the server.

 -- Attribute: HTTPConnection.blocksize

     Buffer size in bytes for sending a file-like message body.

     Added in version 3.7.

As an alternative to using the *note request(): ccf. method described
above, you can also send your request step by step, by using the four
functions below.

 -- Method: HTTPConnection.putrequest (method, url, skip_host=False,
          skip_accept_encoding=False)

     This should be the first call after the connection to the server
     has been made.  It sends a line to the server consisting of the
     'method' string, the 'url' string, and the HTTP version
     (‘HTTP/1.1’).  To disable automatic sending of ‘Host:’ or
     ‘Accept-Encoding:’ headers (for example to accept additional
     content encodings), specify 'skip_host' or 'skip_accept_encoding'
     with non-False values.

 -- Method: HTTPConnection.putheader (header, argument[, ...])

     Send an RFC 822(5)-style header to the server.  It sends a line to
     the server consisting of the header, a colon and a space, and the
     first argument.  If more arguments are given, continuation lines
     are sent, each consisting of a tab and an argument.

 -- Method: HTTPConnection.endheaders (message_body=None, *,
          encode_chunked=False)

     Send a blank line to the server, signalling the end of the headers.
     The optional 'message_body' argument can be used to pass a message
     body associated with the request.

     If 'encode_chunked' is ‘True’, the result of each iteration of
     'message_body' will be chunk-encoded as specified in RFC 7230(6),
     Section 3.3.1.  How the data is encoded is dependent on the type of
     'message_body'.  If 'message_body' implements the *note buffer
     interface: 2e8. the encoding will result in a single chunk.  If
     'message_body' is a *note collections.abc.Iterable: 2405, each
     iteration of 'message_body' will result in a chunk.  If
     'message_body' is a *note file object: 1208, each call to ‘.read()’
     will result in a chunk.  The method automatically signals the end
     of the chunk-encoded data immediately after 'message_body'.

          Note: Due to the chunked encoding specification, empty chunks
          yielded by an iterator body will be ignored by the
          chunk-encoder.  This is to avoid premature termination of the
          read of the request by the target server due to malformed
          encoding.

     Changed in version 3.6: Added chunked encoding support and the
     'encode_chunked' parameter.

 -- Method: HTTPConnection.send (data)

     Send data to the server.  This should be used directly only after
     the *note endheaders(): cd0. method has been called and before
     *note getresponse(): e3a. is called.

     Raises an *note auditing event: 1a15. ‘http.client.send’ with
     arguments ‘self’, ‘data’.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html#section-5.1.2

   (2) https://datatracker.ietf.org/doc/html/rfc2616.html#section-14.23

   (3) https://datatracker.ietf.org/doc/html/rfc2616.html#section-5.1.2

   (4) https://datatracker.ietf.org/doc/html/rfc7231#section-4.3.6

   (5) https://datatracker.ietf.org/doc/html/rfc822.html

   (6) https://datatracker.ietf.org/doc/html/rfc7230.html


File: python.info,  Node: HTTPResponse Objects,  Next: Examples<27>,  Prev: HTTPConnection Objects,  Up: http client — HTTP protocol client

5.22.10.2 HTTPResponse Objects
..............................

An *note HTTPResponse: 1112. instance wraps the HTTP response from the
server.  It provides access to the request headers and the entity body.
The response is an iterable object and can be used in a with statement.

Changed in version 3.5: The *note io.BufferedIOBase: 697. interface is
now implemented and all of its reader operations are supported.

 -- Method: HTTPResponse.read ([amt])

     Reads and returns the response body, or up to the next 'amt' bytes.

 -- Method: HTTPResponse.readinto (b)

     Reads up to the next len(b) bytes of the response body into the
     buffer 'b'.  Returns the number of bytes read.

     Added in version 3.3.

 -- Method: HTTPResponse.getheader (name, default=None)

     Return the value of the header 'name', or 'default' if there is no
     header matching 'name'.  If there is more than one header with the
     name 'name', return all of the values joined by ‘, ‘.  If 'default'
     is any iterable other than a single string, its elements are
     similarly returned joined by commas.

 -- Method: HTTPResponse.getheaders ()

     Return a list of (header, value) tuples.

 -- Method: HTTPResponse.fileno ()

     Return the ‘fileno’ of the underlying socket.

 -- Attribute: HTTPResponse.msg

     A *note http.client.HTTPMessage: 3c9f. instance containing the
     response headers.  ‘http.client.HTTPMessage’ is a subclass of *note
     email.message.Message: 27c.

 -- Attribute: HTTPResponse.version

     HTTP protocol version used by server.  10 for HTTP/1.0, 11 for
     HTTP/1.1.

 -- Attribute: HTTPResponse.url

     URL of the resource retrieved, commonly used to determine if a
     redirect was followed.

 -- Attribute: HTTPResponse.headers

     Headers of the response in the form of an *note
     email.message.EmailMessage: 27b. instance.

 -- Attribute: HTTPResponse.status

     Status code returned by server.

 -- Attribute: HTTPResponse.reason

     Reason phrase returned by server.

 -- Attribute: HTTPResponse.debuglevel

     A debugging hook.  If *note debuglevel: 3cc4. is greater than zero,
     messages will be printed to stdout as the response is read and
     parsed.

 -- Attribute: HTTPResponse.closed

     Is ‘True’ if the stream is closed.

 -- Method: HTTPResponse.geturl ()

     Deprecated since version 3.9: Deprecated in favor of *note url:
     3cc1.

 -- Method: HTTPResponse.info ()

     Deprecated since version 3.9: Deprecated in favor of *note headers:
     3cc2.

 -- Method: HTTPResponse.getcode ()

     Deprecated since version 3.9: Deprecated in favor of *note status:
     3cc3.


File: python.info,  Node: Examples<27>,  Next: HTTPMessage Objects,  Prev: HTTPResponse Objects,  Up: http client — HTTP protocol client

5.22.10.3 Examples
..................

Here is an example session that uses the ‘GET’ method:

     >>> import http.client
     >>> conn = http.client.HTTPSConnection("www.python.org")
     >>> conn.request("GET", "/")
     >>> r1 = conn.getresponse()
     >>> print(r1.status, r1.reason)
     200 OK
     >>> data1 = r1.read()  # This will return entire content.
     >>> # The following example demonstrates reading data in chunks.
     >>> conn.request("GET", "/")
     >>> r1 = conn.getresponse()
     >>> while chunk := r1.read(200):
     ...     print(repr(chunk))
     b'<!doctype html>\n<!--[if"...
     ...
     >>> # Example of an invalid request
     >>> conn = http.client.HTTPSConnection("docs.python.org")
     >>> conn.request("GET", "/parrot.spam")
     >>> r2 = conn.getresponse()
     >>> print(r2.status, r2.reason)
     404 Not Found
     >>> data2 = r2.read()
     >>> conn.close()

Here is an example session that uses the ‘HEAD’ method.  Note that the
‘HEAD’ method never returns any data.

     >>> import http.client
     >>> conn = http.client.HTTPSConnection("www.python.org")
     >>> conn.request("HEAD", "/")
     >>> res = conn.getresponse()
     >>> print(res.status, res.reason)
     200 OK
     >>> data = res.read()
     >>> print(len(data))
     0
     >>> data == b''
     True

Here is an example session that uses the ‘POST’ method:

     >>> import http.client, urllib.parse
     >>> params = urllib.parse.urlencode({'@number': 12524, '@type': 'issue', '@action': 'show'})
     >>> headers = {"Content-type": "application/x-www-form-urlencoded",
     ...            "Accept": "text/plain"}
     >>> conn = http.client.HTTPConnection("bugs.python.org")
     >>> conn.request("POST", "", params, headers)
     >>> response = conn.getresponse()
     >>> print(response.status, response.reason)
     302 Found
     >>> data = response.read()
     >>> data
     b'Redirecting to <a href="https://bugs.python.org/issue12524">https://bugs.python.org/issue12524</a>'
     >>> conn.close()

Client side HTTP ‘PUT’ requests are very similar to ‘POST’ requests.
The difference lies only on the server side where HTTP servers will
allow resources to be created via ‘PUT’ requests.  It should be noted
that custom HTTP methods are also handled in *note
urllib.request.Request: 1013. by setting the appropriate method
attribute.  Here is an example session that uses the ‘PUT’ method:

     >>> # This creates an HTTP request
     >>> # with the content of BODY as the enclosed representation
     >>> # for the resource http://localhost:8080/file
     ...
     >>> import http.client
     >>> BODY = "***filecontents***"
     >>> conn = http.client.HTTPConnection("localhost", 8080)
     >>> conn.request("PUT", "/file", BODY)
     >>> response = conn.getresponse()
     >>> print(response.status, response.reason)
     200, OK


File: python.info,  Node: HTTPMessage Objects,  Prev: Examples<27>,  Up: http client — HTTP protocol client

5.22.10.4 HTTPMessage Objects
.............................

 -- Class: http.client.HTTPMessage (email.message.Message)

An *note http.client.HTTPMessage: 3c9f. instance holds the headers from
an HTTP response.  It is implemented using the *note
email.message.Message: 27c. class.


File: python.info,  Node: ftplib — FTP protocol client,  Next: poplib — POP3 protocol client,  Prev: http client — HTTP protocol client,  Up: Internet Protocols and Support

5.22.11 ‘ftplib’ — FTP protocol client
--------------------------------------

'Source code:' Lib/ftplib.py(1)

__________________________________________________________________

This module defines the class *note FTP: 903. and a few related items.
The ‘FTP’ class implements the client side of the FTP protocol.  You can
use this to write Python programs that perform a variety of automated
FTP jobs, such as mirroring other FTP servers.  It is also used by the
module *note urllib.request: 10b. to handle URLs that use FTP. For more
information on FTP (File Transfer Protocol), see internet RFC 959(2).

The default encoding is UTF-8, following RFC 2640(3).

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

Here’s a sample session using the ‘ftplib’ module:

     >>> from ftplib import FTP
     >>> ftp = FTP('ftp.us.debian.org')  # connect to host, default port
     >>> ftp.login()                     # user anonymous, passwd anonymous@
     '230 Login successful.'
     >>> ftp.cwd('debian')               # change into "debian" directory
     '250 Directory successfully changed.'
     >>> ftp.retrlines('LIST')           # list directory contents
     -rw-rw-r--    1 1176     1176         1063 Jun 15 10:18 README
     ...
     drwxr-sr-x    5 1176     1176         4096 Dec 19  2000 pool
     drwxr-sr-x    4 1176     1176         4096 Nov 17  2008 project
     drwxr-xr-x    3 1176     1176         4096 Oct 10  2012 tools
     '226 Directory send OK.'
     >>> with open('README', 'wb') as fp:
     >>>     ftp.retrbinary('RETR README', fp.write)
     '226 Transfer complete.'
     >>> ftp.quit()
     '221 Goodbye.'

* Menu:

* Reference: Reference<6>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ftplib.py

   (2) https://datatracker.ietf.org/doc/html/rfc959.html

   (3) https://datatracker.ietf.org/doc/html/rfc2640.html


File: python.info,  Node: Reference<6>,  Up: ftplib — FTP protocol client

5.22.11.1 Reference
...................

* Menu:

* FTP objects::
* FTP_TLS objects::
* Module variables::


File: python.info,  Node: FTP objects,  Next: FTP_TLS objects,  Up: Reference<6>

5.22.11.2 FTP objects
.....................

 -- Class: ftplib.FTP (host='', user='', passwd='', acct='',
          timeout=None, source_address=None, *, encoding='utf-8')

     Return a new instance of the ‘FTP’ class.


     Parameters:

        * ‘host’ (*note str: 44f.) – The hostname to connect to.  If
          given, ‘connect(host)’ is implicitly called by the
          constructor.

        * ‘user’ (*note str: 44f.) – The username to log in with
          (default: ‘'anonymous'’).  If given, ‘login(host, passwd,
          acct)’ is implicitly called by the constructor.

        * ‘passwd’ (*note str: 44f.) – The password to use when logging
          in.  If not given, and if 'passwd' is the empty string or
          ‘"-"’, a password will be automatically generated.

        * ‘acct’ (*note str: 44f.) – Account information to be used for
          the ‘ACCT’ FTP command.  Few systems implement this.  See
          RFC-959(1) for more details.

        * ‘timeout’ (*note float: 2f7.‘ | ’‘None’) – A timeout in
          seconds for blocking operations like *note connect(): 3cd3.
          (default: the global default timeout setting).

        * ‘source_address’ (*note tuple: 373.‘ | ’‘None’) – A 2-tuple
          ‘(host, port)’ for the socket to bind to as its source address
          before connecting.

        * ‘encoding’ (*note str: 44f.) – The encoding for directories
          and filenames (default: ‘'utf-8'’).

     The ‘FTP’ class supports the *note with: 5d5. statement, e.g.:

          >>> from ftplib import FTP
          >>> with FTP("ftp1.at.proftpd.org") as ftp:
          ...     ftp.login()
          ...     ftp.dir()
          ...
          '230 Anonymous login ok, restrictions apply.'
          dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 .
          dr-xr-xr-x   9 ftp      ftp           154 May  6 10:43 ..
          dr-xr-xr-x   5 ftp      ftp          4096 May  6 10:43 CentOS
          dr-xr-xr-x   3 ftp      ftp            18 Jul 10  2008 Fedora
          >>>

     Changed in version 3.2: Support for the *note with: 5d5. statement
     was added.

     Changed in version 3.3: 'source_address' parameter was added.

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket.  The 'encoding' parameter was
     added, and the default was changed from Latin-1 to UTF-8 to follow
     RFC 2640(2).

     Several ‘FTP’ methods are available in two flavors: one for
     handling text files and another for binary files.  The methods are
     named for the command which is used followed by ‘lines’ for the
     text version or ‘binary’ for the binary version.

     ‘FTP’ instances have the following methods:

      -- Method: set_debuglevel (level)

          Set the instance’s debugging level as an *note int: 257.  This
          controls the amount of debugging output printed.  The debug
          levels are:

             * ‘0’ (default): No debug output.

             * ‘1’: Produce a moderate amount of debug output, generally
               a single line per request.

             * ‘2’ or higher: Produce the maximum amount of debugging
               output, logging each line sent and received on the
               control connection.

      -- Method: connect (host='', port=0, timeout=None,
               source_address=None)

          Connect to the given host and port.  This function should be
          called only once for each instance; it should not be called if
          a 'host' argument was given when the ‘FTP’ instance was
          created.  All other ‘FTP’ methods can only be called after a
          connection has successfully been made.


          Parameters:

             * ‘host’ (*note str: 44f.) – The host to connect to.

             * ‘port’ (*note int: 257.) – The TCP port to connect to
               (default: ‘21’, as specified by the FTP protocol
               specification).  It is rarely needed to specify a
               different port number.

             * ‘timeout’ (*note float: 2f7.‘ | ’‘None’) – A timeout in
               seconds for the connection attempt (default: the global
               default timeout setting).

             * ‘source_address’ (*note tuple: 373.‘ | ’‘None’) – A
               2-tuple ‘(host, port)’ for the socket to bind to as its
               source address before connecting.

          Raises an *note auditing event: 1a15. ‘ftplib.connect’ with
          arguments ‘self’, ‘host’, ‘port’.

          Changed in version 3.3: 'source_address' parameter was added.

      -- Method: getwelcome ()

          Return the welcome message sent by the server in reply to the
          initial connection.  (This message sometimes contains
          disclaimers or help information that may be relevant to the
          user.)

      -- Method: login (user='anonymous', passwd='', acct='')

          Log on to the connected FTP server.  This function should be
          called only once for each instance, after a connection has
          been established; it should not be called if the 'host' and
          'user' arguments were given when the ‘FTP’ instance was
          created.  Most FTP commands are only allowed after the client
          has logged in.


          Parameters:

             * ‘user’ (*note str: 44f.) – The username to log in with
               (default: ‘'anonymous'’).

             * ‘passwd’ (*note str: 44f.) – The password to use when
               logging in.  If not given, and if 'passwd' is the empty
               string or ‘"-"’, a password will be automatically
               generated.

             * ‘acct’ (*note str: 44f.) – Account information to be used
               for the ‘ACCT’ FTP command.  Few systems implement this.
               See RFC-959(3) for more details.

      -- Method: abort ()

          Abort a file transfer that is in progress.  Using this does
          not always work, but it’s worth a try.

      -- Method: sendcmd (cmd)

          Send a simple command string to the server and return the
          response string.

          Raises an *note auditing event: 1a15. ‘ftplib.sendcmd’ with
          arguments ‘self’, ‘cmd’.

      -- Method: voidcmd (cmd)

          Send a simple command string to the server and handle the
          response.  Return the response string if the response code
          corresponds to success (codes in the range 200–299).  Raise
          *note error_reply: 3cda. otherwise.

          Raises an *note auditing event: 1a15. ‘ftplib.sendcmd’ with
          arguments ‘self’, ‘cmd’.

      -- Method: retrbinary (cmd, callback, blocksize=8192, rest=None)

          Retrieve a file in binary transfer mode.


          Parameters:

             * ‘cmd’ (*note str: 44f.) – An appropriate ‘RETR’ command:
               ‘"RETR FILENAME"’.

             * ‘callback’ (*note callable: 2acb.) – A single parameter
               callable that is called for each block of data received,
               with its single argument being the data as *note bytes:
               1c2.

             * ‘blocksize’ (*note int: 257.) – The maximum chunk size to
               read on the low-level *note socket: dcf. object created
               to do the actual transfer.  This also corresponds to the
               largest size of data that will be passed to 'callback'.
               Defaults to ‘8192’.

             * ‘rest’ (*note int: 257.) – A ‘REST’ command to be sent to
               the server.  See the documentation for the 'rest'
               parameter of the *note transfercmd(): 3cdc. method.

      -- Method: retrlines (cmd, callback=None)

          Retrieve a file or directory listing in the encoding specified
          by the 'encoding' parameter at initialization.  'cmd' should
          be an appropriate ‘RETR’ command (see *note retrbinary():
          3cdb.) or a command such as ‘LIST’ or ‘NLST’ (usually just the
          string ‘'LIST'’).  ‘LIST’ retrieves a list of files and
          information about those files.  ‘NLST’ retrieves a list of
          file names.  The 'callback' function is called for each line
          with a string argument containing the line with the trailing
          CRLF stripped.  The default 'callback' prints the line to
          *note sys.stdout: aec.

      -- Method: set_pasv (val)

          Enable “passive” mode if 'val' is true, otherwise disable
          passive mode.  Passive mode is on by default.

      -- Method: storbinary (cmd, fp, blocksize=8192, callback=None,
               rest=None)

          Store a file in binary transfer mode.


          Parameters:

             * ‘cmd’ (*note str: 44f.) – An appropriate ‘STOR’ command:
               ‘"STOR FILENAME"’.

             * ‘fp’ (*note file object: 1208.) – A file object (opened
               in binary mode) which is read until EOF, using its *note
               read(): e4e. method in blocks of size 'blocksize' to
               provide the data to be stored.

             * ‘blocksize’ (*note int: 257.) – The read block size.
               Defaults to ‘8192’.

             * ‘callback’ (*note callable: 2acb.) – A single parameter
               callable that is called for each block of data sent, with
               its single argument being the data as *note bytes: 1c2.

             * ‘rest’ (*note int: 257.) – A ‘REST’ command to be sent to
               the server.  See the documentation for the 'rest'
               parameter of the *note transfercmd(): 3cdc. method.

          Changed in version 3.2: The 'rest' parameter was added.

      -- Method: storlines (cmd, fp, callback=None)

          Store a file in line mode.  'cmd' should be an appropriate
          ‘STOR’ command (see *note storbinary(): 1353.).  Lines are
          read until EOF from the *note file object: 1208. 'fp' (opened
          in binary mode) using its *note readline(): 1373. method to
          provide the data to be stored.  'callback' is an optional
          single parameter callable that is called on each line after it
          is sent.

      -- Method: transfercmd (cmd, rest=None)

          Initiate a transfer over the data connection.  If the transfer
          is active, send an ‘EPRT’ or ‘PORT’ command and the transfer
          command specified by 'cmd', and accept the connection.  If the
          server is passive, send an ‘EPSV’ or ‘PASV’ command, connect
          to it, and start the transfer command.  Either way, return the
          socket for the connection.

          If optional 'rest' is given, a ‘REST’ command is sent to the
          server, passing 'rest' as an argument.  'rest' is usually a
          byte offset into the requested file, telling the server to
          restart sending the file’s bytes at the requested offset,
          skipping over the initial bytes.  Note however that the
          ‘transfercmd()’ method converts 'rest' to a string with the
          'encoding' parameter specified at initialization, but no check
          is performed on the string’s contents.  If the server does not
          recognize the ‘REST’ command, an *note error_reply: 3cda.
          exception will be raised.  If this happens, simply call
          ‘transfercmd()’ without a 'rest' argument.

      -- Method: ntransfercmd (cmd, rest=None)

          Like *note transfercmd(): 3cdc, but returns a tuple of the
          data connection and the expected size of the data.  If the
          expected size could not be computed, ‘None’ will be returned
          as the expected size.  'cmd' and 'rest' means the same thing
          as in ‘transfercmd()’.

      -- Method: mlsd (path='', facts=[])

          List a directory in a standardized format by using ‘MLSD’
          command ( RFC 3659(4)).  If 'path' is omitted the current
          directory is assumed.  'facts' is a list of strings
          representing the type of information desired (e.g.  ‘["type",
          "size", "perm"]’).  Return a generator object yielding a tuple
          of two elements for every file found in path.  First element
          is the file name, the second one is a dictionary containing
          facts about the file name.  Content of this dictionary might
          be limited by the 'facts' argument but server is not
          guaranteed to return all requested facts.

          Added in version 3.3.

      -- Method: nlst (argument[, ...])

          Return a list of file names as returned by the ‘NLST’ command.
          The optional 'argument' is a directory to list (default is the
          current server directory).  Multiple arguments can be used to
          pass non-standard options to the ‘NLST’ command.

               Note: If your server supports the command, *note mlsd():
               1106. offers a better API.

      -- Method: dir (argument[, ...])

          Produce a directory listing as returned by the ‘LIST’ command,
          printing it to standard output.  The optional 'argument' is a
          directory to list (default is the current server directory).
          Multiple arguments can be used to pass non-standard options to
          the ‘LIST’ command.  If the last argument is a function, it is
          used as a 'callback' function as for *note retrlines(): 3cdd.;
          the default prints to *note sys.stdout: aec.  This method
          returns ‘None’.

               Note: If your server supports the command, *note mlsd():
               1106. offers a better API.

      -- Method: rename (fromname, toname)

          Rename file 'fromname' on the server to 'toname'.

      -- Method: delete (filename)

          Remove the file named 'filename' from the server.  If
          successful, returns the text of the response, otherwise raises
          *note error_perm: 3ce3. on permission errors or *note
          error_reply: 3cda. on other errors.

      -- Method: cwd (pathname)

          Set the current directory on the server.

      -- Method: mkd (pathname)

          Create a new directory on the server.

      -- Method: pwd ()

          Return the pathname of the current directory on the server.

      -- Method: rmd (dirname)

          Remove the directory named 'dirname' on the server.

      -- Method: size (filename)

          Request the size of the file named 'filename' on the server.
          On success, the size of the file is returned as an integer,
          otherwise ‘None’ is returned.  Note that the ‘SIZE’ command is
          not standardized, but is supported by many common server
          implementations.

      -- Method: quit ()

          Send a ‘QUIT’ command to the server and close the connection.
          This is the “polite” way to close a connection, but it may
          raise an exception if the server responds with an error to the
          ‘QUIT’ command.  This implies a call to the *note close():
          3cea. method which renders the ‘FTP’ instance useless for
          subsequent calls (see below).

      -- Method: close ()

          Close the connection unilaterally.  This should not be applied
          to an already closed connection such as after a successful
          call to *note quit(): 3ce9.  After this call the ‘FTP’
          instance should not be used any more (after a call to
          ‘close()’ or ‘quit()’ you cannot reopen the connection by
          issuing another *note login(): 3cd6. method).

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc959.html

   (2) https://datatracker.ietf.org/doc/html/rfc2640.html

   (3) https://datatracker.ietf.org/doc/html/rfc959.html

   (4) https://datatracker.ietf.org/doc/html/rfc3659.html


File: python.info,  Node: FTP_TLS objects,  Next: Module variables,  Prev: FTP objects,  Up: Reference<6>

5.22.11.3 FTP_TLS objects
.........................

 -- Class: ftplib.FTP_TLS (host='', user='', passwd='', acct='', *,
          context=None, timeout=None, source_address=None,
          encoding='utf-8')

     An *note FTP: 903. subclass which adds TLS support to FTP as
     described in RFC 4217(1).  Connect to port 21 implicitly securing
     the FTP control connection before authenticating.

          Note: The user must explicitly secure the data connection by
          calling the *note prot_p(): 3cec. method.


     Parameters:

        * ‘host’ (*note str: 44f.) – The hostname to connect to.  If
          given, ‘connect(host)’ is implicitly called by the
          constructor.

        * ‘user’ (*note str: 44f.) – The username to log in with
          (default: ‘'anonymous'’).  If given, ‘login(host, passwd,
          acct)’ is implicitly called by the constructor.

        * ‘passwd’ (*note str: 44f.) – The password to use when logging
          in.  If not given, and if 'passwd' is the empty string or
          ‘"-"’, a password will be automatically generated.

        * ‘acct’ (*note str: 44f.) – Account information to be used for
          the ‘ACCT’ FTP command.  Few systems implement this.  See
          RFC-959(2) for more details.

        * ‘context’ (*note ssl.SSLContext: 294.) – An SSL context object
          which allows bundling SSL configuration options, certificates
          and private keys into a single, potentially long-lived,
          structure.  Please read *note Security considerations: 3564.
          for best practices.

        * ‘timeout’ (*note float: 2f7.‘ | ’‘None’) – A timeout in
          seconds for blocking operations like *note connect(): 3cd3.
          (default: the global default timeout setting).

        * ‘source_address’ (*note tuple: 373.‘ | ’‘None’) – A 2-tuple
          ‘(host, port)’ for the socket to bind to as its source address
          before connecting.

        * ‘encoding’ (*note str: 44f.) – The encoding for directories
          and filenames (default: ‘'utf-8'’).

     Added in version 3.2.

     Changed in version 3.3: Added the 'source_address' parameter.

     Changed in version 3.4: The class now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indication' (see *note ssl.HAS_SNI: 36a6.).

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket.  The 'encoding' parameter was
     added, and the default was changed from Latin-1 to UTF-8 to follow
     RFC 2640(3).

     Changed in version 3.12: The deprecated 'keyfile' and 'certfile'
     parameters have been removed.

     Here’s a sample session using the ‘FTP_TLS’ class:

          >>> ftps = FTP_TLS('ftp.pureftpd.org')
          >>> ftps.login()
          '230 Anonymous user logged in'
          >>> ftps.prot_p()
          '200 Data protection level set to "private"'
          >>> ftps.nlst()
          ['6jack', 'OpenBSD', 'antilink', 'blogbench', 'bsdcam', 'clockspeed', 'djbdns-jedi', 'docs', 'eaccelerator-jedi', 'favicon.ico', 'francotone', 'fugu', 'ignore', 'libpuzzle', 'metalog', 'minidentd', 'misc', 'mysql-udf-global-user-variables', 'php-jenkins-hash', 'php-skein-hash', 'php-webdav', 'phpaudit', 'phpbench', 'pincaster', 'ping', 'posto', 'pub', 'public', 'public_keys', 'pure-ftpd', 'qscan', 'qtc', 'sharedance', 'skycache', 'sound', 'tmp', 'ucarp']

     ‘FTP_TLS’ class inherits from *note FTP: 903, defining these
     additional methods and attributes:

      -- Attribute: ssl_version

          The SSL version to use (defaults to *note ssl.PROTOCOL_SSLv23:
          3698.).

      -- Method: auth ()

          Set up a secure control connection by using TLS or SSL,
          depending on what is specified in the *note ssl_version: 3ced.
          attribute.

          Changed in version 3.4: The method now supports hostname check
          with *note ssl.SSLContext.check_hostname: 3694. and 'Server
          Name Indication' (see *note ssl.HAS_SNI: 36a6.).

      -- Method: ccc ()

          Revert control channel back to plaintext.  This can be useful
          to take advantage of firewalls that know how to handle NAT
          with non-secure FTP without opening fixed ports.

          Added in version 3.3.

      -- Method: prot_p ()

          Set up secure data connection.

      -- Method: prot_c ()

          Set up clear text data connection.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc4217.html

   (2) https://datatracker.ietf.org/doc/html/rfc959.html

   (3) https://datatracker.ietf.org/doc/html/rfc2640.html


File: python.info,  Node: Module variables,  Prev: FTP_TLS objects,  Up: Reference<6>

5.22.11.4 Module variables
..........................

 -- Exception: ftplib.error_reply

     Exception raised when an unexpected reply is received from the
     server.

 -- Exception: ftplib.error_temp

     Exception raised when an error code signifying a temporary error
     (response codes in the range 400–499) is received.

 -- Exception: ftplib.error_perm

     Exception raised when an error code signifying a permanent error
     (response codes in the range 500–599) is received.

 -- Exception: ftplib.error_proto

     Exception raised when a reply is received from the server that does
     not fit the response specifications of the File Transfer Protocol,
     i.e.  begin with a digit in the range 1–5.

 -- Data: ftplib.all_errors

     The set of all exceptions (as a tuple) that methods of *note FTP:
     903. instances may raise as a result of problems with the FTP
     connection (as opposed to programming errors made by the caller).
     This set includes the four exceptions listed above as well as *note
     OSError: 41a. and *note EOFError: 1321.

See also
........

Module *note netrc: 9b.

     Parser for the ‘.netrc’ file format.  The file ‘.netrc’ is
     typically used by FTP clients to load user authentication
     information before prompting the user.


File: python.info,  Node: poplib — POP3 protocol client,  Next: imaplib — IMAP4 protocol client,  Prev: ftplib — FTP protocol client,  Up: Internet Protocols and Support

5.22.12 ‘poplib’ — POP3 protocol client
---------------------------------------

'Source code:' Lib/poplib.py(1)

__________________________________________________________________

This module defines a class, *note POP3: 92d, which encapsulates a
connection to a POP3 server and implements the protocol as defined in
RFC 1939(2).  The ‘POP3’ class supports both the minimal and optional
command sets from RFC 1939(3).  The ‘POP3’ class also supports the
‘STLS’ command introduced in RFC 2595(4) to enable encrypted
communication on an already established connection.

Additionally, this module provides a class *note POP3_SSL: 92e, which
provides support for connecting to POP3 servers that use SSL as an
underlying protocol layer.

Note that POP3, though widely supported, is obsolescent.  The
implementation quality of POP3 servers varies widely, and too many are
quite poor.  If your mailserver supports IMAP, you would be better off
using the *note imaplib.IMAP4: 90c. class, as IMAP servers tend to be
better implemented.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

The ‘poplib’ module provides two classes:

 -- Class: poplib.POP3 (host, port=POP3_PORT[, timeout])

     This class implements the actual POP3 protocol.  The connection is
     created when the instance is initialized.  If 'port' is omitted,
     the standard POP3 port (110) is used.  The optional 'timeout'
     parameter specifies a timeout in seconds for the connection attempt
     (if not specified, the global default timeout setting will be
     used).

     Raises an *note auditing event: 1a15. ‘poplib.connect’ with
     arguments ‘self’, ‘host’, ‘port’.

     All commands will raise an *note auditing event: 1a15.
     ‘poplib.putline’ with arguments ‘self’ and ‘line’, where ‘line’ is
     the bytes about to be sent to the remote host.

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket.

 -- Class: poplib.POP3_SSL (host, port=POP3_SSL_PORT, *, timeout=None,
          context=None)

     This is a subclass of *note POP3: 92d. that connects to the server
     over an SSL encrypted socket.  If 'port' is not specified, 995, the
     standard POP3-over-SSL port is used.  'timeout' works as in the
     ‘POP3’ constructor.  'context' is an optional *note ssl.SSLContext:
     294. object which allows bundling SSL configuration options,
     certificates and private keys into a single (potentially
     long-lived) structure.  Please read *note Security considerations:
     3564. for best practices.

     Raises an *note auditing event: 1a15. ‘poplib.connect’ with
     arguments ‘self’, ‘host’, ‘port’.

     All commands will raise an *note auditing event: 1a15.
     ‘poplib.putline’ with arguments ‘self’ and ‘line’, where ‘line’ is
     the bytes about to be sent to the remote host.

     Changed in version 3.2: 'context' parameter added.

     Changed in version 3.4: The class now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indication' (see *note ssl.HAS_SNI: 36a6.).

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket.

     Changed in version 3.12: The deprecated 'keyfile' and 'certfile'
     parameters have been removed.

One exception is defined as an attribute of the ‘poplib’ module:

 -- Exception: poplib.error_proto

     Exception raised on any errors from this module (errors from *note
     socket: cc. module are not caught).  The reason for the exception
     is passed to the constructor as a string.

See also
........

Module *note imaplib: 74.

     The standard Python IMAP module.

Frequently Asked Questions About Fetchmail(5)

     The FAQ for the ‘fetchmail’ POP/IMAP client collects information on
     POP3 server variations and RFC noncompliance that may be useful if
     you need to write an application based on the POP protocol.

* Menu:

* POP3 Objects::
* POP3 Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/poplib.py

   (2) https://datatracker.ietf.org/doc/html/rfc1939.html

   (3) https://datatracker.ietf.org/doc/html/rfc1939.html

   (4) https://datatracker.ietf.org/doc/html/rfc2595.html

   (5) http://www.catb.org/~esr/fetchmail/fetchmail-FAQ.html


File: python.info,  Node: POP3 Objects,  Next: POP3 Example,  Up: poplib — POP3 protocol client

5.22.12.1 POP3 Objects
......................

All POP3 commands are represented by methods of the same name, in
lowercase; most return the response text sent by the server.

A *note POP3: 92d. instance has the following methods:

 -- Method: POP3.set_debuglevel (level)

     Set the instance’s debugging level.  This controls the amount of
     debugging output printed.  The default, ‘0’, produces no debugging
     output.  A value of ‘1’ produces a moderate amount of debugging
     output, generally a single line per request.  A value of ‘2’ or
     higher produces the maximum amount of debugging output, logging
     each line sent and received on the control connection.

 -- Method: POP3.getwelcome ()

     Returns the greeting string sent by the POP3 server.

 -- Method: POP3.capa ()

     Query the server’s capabilities as specified in RFC 2449(1).
     Returns a dictionary in the form ‘{'name': ['param'...]}’.

     Added in version 3.4.

 -- Method: POP3.user (username)

     Send user command, response should indicate that a password is
     required.

 -- Method: POP3.pass_ (password)

     Send password, response includes message count and mailbox size.
     Note: the mailbox on the server is locked until *note quit(): 11df.
     is called.

 -- Method: POP3.apop (user, secret)

     Use the more secure APOP authentication to log into the POP3
     server.

 -- Method: POP3.rpop (user)

     Use RPOP authentication (similar to UNIX r-commands) to log into
     POP3 server.

 -- Method: POP3.stat ()

     Get mailbox status.  The result is a tuple of 2 integers: ‘(message
     count, mailbox size)’.

 -- Method: POP3.list ([which])

     Request message list, result is in the form ‘(response, ['mesg_num
     octets', ...], octets)’.  If 'which' is set, it is the message to
     list.

 -- Method: POP3.retr (which)

     Retrieve whole message number 'which', and set its seen flag.
     Result is in form ‘(response, ['line', ...], octets)’.

 -- Method: POP3.dele (which)

     Flag message number 'which' for deletion.  On most servers
     deletions are not actually performed until QUIT (the major
     exception is Eudora QPOP, which deliberately violates the RFCs by
     doing pending deletes on any disconnect).

 -- Method: POP3.rset ()

     Remove any deletion marks for the mailbox.

 -- Method: POP3.noop ()

     Do nothing.  Might be used as a keep-alive.

 -- Method: POP3.quit ()

     Signoff: commit changes, unlock mailbox, drop connection.

 -- Method: POP3.top (which, howmuch)

     Retrieves the message header plus 'howmuch' lines of the message
     after the header of message number 'which'.  Result is in form
     ‘(response, ['line', ...], octets)’.

     The POP3 TOP command this method uses, unlike the RETR command,
     doesn’t set the message’s seen flag; unfortunately, TOP is poorly
     specified in the RFCs and is frequently broken in off-brand
     servers.  Test this method by hand against the POP3 servers you
     will use before trusting it.

 -- Method: POP3.uidl (which=None)

     Return message digest (unique id) list.  If 'which' is specified,
     result contains the unique id for that message in the form
     ‘'response mesgnum uid’, otherwise result is list ‘(response,
     ['mesgnum uid', ...], octets)’.

 -- Method: POP3.utf8 ()

     Try to switch to UTF-8 mode.  Returns the server response if
     successful, raises *note error_proto: 11e0. if not.  Specified in
     RFC 6856(2).

     Added in version 3.5.

 -- Method: POP3.stls (context=None)

     Start a TLS session on the active connection as specified in RFC
     2595(3).  This is only allowed before user authentication

     'context' parameter is a *note ssl.SSLContext: 294. object which
     allows bundling SSL configuration options, certificates and private
     keys into a single (potentially long-lived) structure.  Please read
     *note Security considerations: 3564. for best practices.

     This method supports hostname checking via *note
     ssl.SSLContext.check_hostname: 3694. and 'Server Name Indication'
     (see *note ssl.HAS_SNI: 36a6.).

     Added in version 3.4.

Instances of *note POP3_SSL: 92e. have no additional methods.  The
interface of this subclass is identical to its parent.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2449.html

   (2) https://datatracker.ietf.org/doc/html/rfc6856.html

   (3) https://datatracker.ietf.org/doc/html/rfc2595.html


File: python.info,  Node: POP3 Example,  Prev: POP3 Objects,  Up: poplib — POP3 protocol client

5.22.12.2 POP3 Example
......................

Here is a minimal example (without error checking) that opens a mailbox
and retrieves and prints all messages:

     import getpass, poplib

     M = poplib.POP3('localhost')
     M.user(getpass.getuser())
     M.pass_(getpass.getpass())
     numMessages = len(M.list()[1])
     for i in range(numMessages):
         for j in M.retr(i+1)[1]:
             print(j)

At the end of the module, there is a test section that contains a more
extensive example of usage.


File: python.info,  Node: imaplib — IMAP4 protocol client,  Next: smtplib — SMTP protocol client,  Prev: poplib — POP3 protocol client,  Up: Internet Protocols and Support

5.22.13 ‘imaplib’ — IMAP4 protocol client
-----------------------------------------

'Source code:' Lib/imaplib.py(1)

__________________________________________________________________

This module defines three classes, *note IMAP4: 90c, *note IMAP4_SSL:
90d. and *note IMAP4_stream: 90f, which encapsulate a connection to an
IMAP4 server and implement a large subset of the IMAP4rev1 client
protocol as defined in RFC 2060(2).  It is backward compatible with
IMAP4 ( RFC 1730(3)) servers, but note that the ‘STATUS’ command is not
supported in IMAP4.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

Three classes are provided by the ‘imaplib’ module, *note IMAP4: 90c. is
the base class:

 -- Class: imaplib.IMAP4 (host='', port=IMAP4_PORT, timeout=None)

     This class implements the actual IMAP4 protocol.  The connection is
     created and protocol version (IMAP4 or IMAP4rev1) is determined
     when the instance is initialized.  If 'host' is not specified, ‘''’
     (the local host) is used.  If 'port' is omitted, the standard IMAP4
     port (143) is used.  The optional 'timeout' parameter specifies a
     timeout in seconds for the connection attempt.  If timeout is not
     given or is ‘None’, the global default socket timeout is used.

     The ‘IMAP4’ class supports the *note with: 5d5. statement.  When
     used like this, the IMAP4 ‘LOGOUT’ command is issued automatically
     when the ‘with’ statement exits.  E.g.:

          >>> from imaplib import IMAP4
          >>> with IMAP4("domain.org") as M:
          ...     M.noop()
          ...
          ('OK', [b'Nothing Accomplished. d25if65hy903weo.87'])

     Changed in version 3.5: Support for the *note with: 5d5. statement
     was added.

     Changed in version 3.9: The optional 'timeout' parameter was added.

Three exceptions are defined as attributes of the *note IMAP4: 90c.
class:

 -- Exception: IMAP4.error

     Exception raised on any errors.  The reason for the exception is
     passed to the constructor as a string.

 -- Exception: IMAP4.abort

     IMAP4 server errors cause this exception to be raised.  This is a
     sub-class of *note IMAP4.error: 161b.  Note that closing the
     instance and instantiating a new one will usually allow recovery
     from this exception.

 -- Exception: IMAP4.readonly

     This exception is raised when a writable mailbox has its status
     changed by the server.  This is a sub-class of *note IMAP4.error:
     161b.  Some other client now has write permission, and the mailbox
     will need to be re-opened to re-obtain write permission.

There’s also a subclass for secure connections:

 -- Class: imaplib.IMAP4_SSL (host='', port=IMAP4_SSL_PORT, *,
          ssl_context=None, timeout=None)

     This is a subclass derived from *note IMAP4: 90c. that connects
     over an SSL encrypted socket (to use this class you need a socket
     module that was compiled with SSL support).  If 'host' is not
     specified, ‘''’ (the local host) is used.  If 'port' is omitted,
     the standard IMAP4-over-SSL port (993) is used.  'ssl_context' is a
     *note ssl.SSLContext: 294. object which allows bundling SSL
     configuration options, certificates and private keys into a single
     (potentially long-lived) structure.  Please read *note Security
     considerations: 3564. for best practices.

     The optional 'timeout' parameter specifies a timeout in seconds for
     the connection attempt.  If timeout is not given or is ‘None’, the
     global default socket timeout is used.

     Changed in version 3.3: 'ssl_context' parameter was added.

     Changed in version 3.4: The class now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indication' (see *note ssl.HAS_SNI: 36a6.).

     Changed in version 3.9: The optional 'timeout' parameter was added.

     Changed in version 3.12: The deprecated 'keyfile' and 'certfile'
     parameters have been removed.

The second subclass allows for connections created by a child process:

 -- Class: imaplib.IMAP4_stream (command)

     This is a subclass derived from *note IMAP4: 90c. that connects to
     the ‘stdin/stdout’ file descriptors created by passing 'command' to
     ‘subprocess.Popen()’.

The following utility functions are defined:

 -- Function: imaplib.Internaldate2tuple (datestr)

     Parse an IMAP4 ‘INTERNALDATE’ string and return corresponding local
     time.  The return value is a *note time.struct_time: d11. tuple or
     ‘None’ if the string has wrong format.

 -- Function: imaplib.Int2AP (num)

     Converts an integer into a bytes representation using characters
     from the set [‘A’ ..  ‘P’].

 -- Function: imaplib.ParseFlags (flagstr)

     Converts an IMAP4 ‘FLAGS’ response to a tuple of individual flags.

 -- Function: imaplib.Time2Internaldate (date_time)

     Convert 'date_time' to an IMAP4 ‘INTERNALDATE’ representation.  The
     return value is a string in the form: ‘"DD-Mmm-YYYY HH:MM:SS
     +HHMM"’ (including double-quotes).  The 'date_time' argument can be
     a number (int or float) representing seconds since epoch (as
     returned by *note time.time(): 254.), a 9-tuple representing local
     time an instance of *note time.struct_time: d11. (as returned by
     *note time.localtime(): 1548.), an aware instance of *note
     datetime.datetime: 1cc, or a double-quoted string.  In the last
     case, it is assumed to already be in the correct format.

Note that IMAP4 message numbers change as the mailbox changes; in
particular, after an ‘EXPUNGE’ command performs deletions the remaining
messages are renumbered.  So it is highly advisable to use UIDs instead,
with the UID command.

At the end of the module, there is a test section that contains a more
extensive example of usage.

See also
........

Documents describing the protocol, sources for servers implementing it,
by the University of Washington’s IMAP Information Center can all be
found at ('Source Code') ‘https://github.com/uw-imap/imap’ ('Not
Maintained').

* Menu:

* IMAP4 Objects::
* IMAP4 Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/imaplib.py

   (2) https://datatracker.ietf.org/doc/html/rfc2060.html

   (3) https://datatracker.ietf.org/doc/html/rfc1730.html


File: python.info,  Node: IMAP4 Objects,  Next: IMAP4 Example,  Up: imaplib — IMAP4 protocol client

5.22.13.1 IMAP4 Objects
.......................

All IMAP4rev1 commands are represented by methods of the same name,
either uppercase or lowercase.

All arguments to commands are converted to strings, except for
‘AUTHENTICATE’, and the last argument to ‘APPEND’ which is passed as an
IMAP4 literal.  If necessary (the string contains IMAP4
protocol-sensitive characters and isn’t enclosed with either parentheses
or double quotes) each string is quoted.  However, the 'password'
argument to the ‘LOGIN’ command is always quoted.  If you want to avoid
having an argument string quoted (eg: the 'flags' argument to ‘STORE’)
then enclose the string in parentheses (eg: ‘r'(\Deleted)'’).

Each command returns a tuple: ‘(type, [data, ...])’ where 'type' is
usually ‘'OK'’ or ‘'NO'’, and 'data' is either the text from the command
response, or mandated results from the command.  Each 'data' is either a
‘bytes’, or a tuple.  If a tuple, then the first part is the header of
the response, and the second part contains the data (ie: ‘literal’
value).

The 'message_set' options to commands below is a string specifying one
or more messages to be acted upon.  It may be a simple message number
(‘'1'’), a range of message numbers (‘'2:4'’), or a group of
non-contiguous ranges separated by commas (‘'1:3,6:9'’).  A range can
contain an asterisk to indicate an infinite upper bound (‘'3:*'’).

An *note IMAP4: 90c. instance has the following methods:

 -- Method: IMAP4.append (mailbox, flags, date_time, message)

     Append 'message' to named mailbox.

 -- Method: IMAP4.authenticate (mechanism, authobject)

     Authenticate command — requires response processing.

     'mechanism' specifies which authentication mechanism is to be used
     - it should appear in the instance variable ‘capabilities’ in the
     form ‘AUTH=mechanism’.

     'authobject' must be a callable object:

          data = authobject(response)

     It will be called to process server continuation responses; the
     'response' argument it is passed will be ‘bytes’.  It should return
     ‘bytes’ 'data' that will be base64 encoded and sent to the server.
     It should return ‘None’ if the client abort response ‘*’ should be
     sent instead.

     Changed in version 3.5: string usernames and passwords are now
     encoded to ‘utf-8’ instead of being limited to ASCII.

 -- Method: IMAP4.check ()

     Checkpoint mailbox on server.

 -- Method: IMAP4.close ()

     Close currently selected mailbox.  Deleted messages are removed
     from writable mailbox.  This is the recommended command before
     ‘LOGOUT’.

 -- Method: IMAP4.copy (message_set, new_mailbox)

     Copy 'message_set' messages onto end of 'new_mailbox'.

 -- Method: IMAP4.create (mailbox)

     Create new mailbox named 'mailbox'.

 -- Method: IMAP4.delete (mailbox)

     Delete old mailbox named 'mailbox'.

 -- Method: IMAP4.deleteacl (mailbox, who)

     Delete the ACLs (remove any rights) set for who on mailbox.

 -- Method: IMAP4.enable (capability)

     Enable 'capability' (see RFC 5161(1)).  Most capabilities do not
     need to be enabled.  Currently only the ‘UTF8=ACCEPT’ capability is
     supported (see RFC 6855(2)).

     Added in version 3.5: The ‘enable()’ method itself, and RFC 6855(3)
     support.

 -- Method: IMAP4.expunge ()

     Permanently remove deleted items from selected mailbox.  Generates
     an ‘EXPUNGE’ response for each deleted message.  Returned data
     contains a list of ‘EXPUNGE’ message numbers in order received.

 -- Method: IMAP4.fetch (message_set, message_parts)

     Fetch (parts of) messages.  'message_parts' should be a string of
     message part names enclosed within parentheses, eg: ‘"(UID
     BODY[TEXT])"’.  Returned data are tuples of message part envelope
     and data.

 -- Method: IMAP4.getacl (mailbox)

     Get the ‘ACL’s for 'mailbox'.  The method is non-standard, but is
     supported by the ‘Cyrus’ server.

 -- Method: IMAP4.getannotation (mailbox, entry, attribute)

     Retrieve the specified ‘ANNOTATION’s for 'mailbox'.  The method is
     non-standard, but is supported by the ‘Cyrus’ server.

 -- Method: IMAP4.getquota (root)

     Get the ‘quota’ 'root'’s resource usage and limits.  This method is
     part of the IMAP4 QUOTA extension defined in rfc2087.

 -- Method: IMAP4.getquotaroot (mailbox)

     Get the list of ‘quota’ ‘roots’ for the named 'mailbox'.  This
     method is part of the IMAP4 QUOTA extension defined in rfc2087.

 -- Method: IMAP4.list ([directory[, pattern]])

     List mailbox names in 'directory' matching 'pattern'.  'directory'
     defaults to the top-level mail folder, and 'pattern' defaults to
     match anything.  Returned data contains a list of ‘LIST’ responses.

 -- Method: IMAP4.login (user, password)

     Identify the client using a plaintext password.  The 'password'
     will be quoted.

 -- Method: IMAP4.login_cram_md5 (user, password)

     Force use of ‘CRAM-MD5’ authentication when identifying the client
     to protect the password.  Will only work if the server ‘CAPABILITY’
     response includes the phrase ‘AUTH=CRAM-MD5’.

     Changed in version 3.13.8: An *note IMAP4.error: 161b. is raised if
     MD5 support is not available.

 -- Method: IMAP4.logout ()

     Shutdown connection to server.  Returns server ‘BYE’ response.

     Changed in version 3.8: The method no longer ignores silently
     arbitrary exceptions.

 -- Method: IMAP4.lsub (directory='""', pattern='*')

     List subscribed mailbox names in directory matching pattern.
     'directory' defaults to the top level directory and 'pattern'
     defaults to match any mailbox.  Returned data are tuples of message
     part envelope and data.

 -- Method: IMAP4.myrights (mailbox)

     Show my ACLs for a mailbox (i.e.  the rights that I have on
     mailbox).

 -- Method: IMAP4.namespace ()

     Returns IMAP namespaces as defined in RFC 2342(4).

 -- Method: IMAP4.noop ()

     Send ‘NOOP’ to server.

 -- Method: IMAP4.open (host, port, timeout=None)

     Opens socket to 'port' at 'host'.  The optional 'timeout' parameter
     specifies a timeout in seconds for the connection attempt.  If
     timeout is not given or is ‘None’, the global default socket
     timeout is used.  Also note that if the 'timeout' parameter is set
     to be zero, it will raise a *note ValueError: 202. to reject
     creating a non-blocking socket.  This method is implicitly called
     by the *note IMAP4: 90c. constructor.  The connection objects
     established by this method will be used in the *note IMAP4.read():
     3d27, *note IMAP4.readline(): 3d28, *note IMAP4.send(): 3d29, and
     *note IMAP4.shutdown(): 3d2a. methods.  You may override this
     method.

     Raises an *note auditing event: 1a15. ‘imaplib.open’ with arguments
     ‘self’, ‘host’, ‘port’.

     Changed in version 3.9: The 'timeout' parameter was added.

 -- Method: IMAP4.partial (message_num, message_part, start, length)

     Fetch truncated part of a message.  Returned data is a tuple of
     message part envelope and data.

 -- Method: IMAP4.proxyauth (user)

     Assume authentication as 'user'.  Allows an authorised
     administrator to proxy into any user’s mailbox.

 -- Method: IMAP4.read (size)

     Reads 'size' bytes from the remote server.  You may override this
     method.

 -- Method: IMAP4.readline ()

     Reads one line from the remote server.  You may override this
     method.

 -- Method: IMAP4.recent ()

     Prompt server for an update.  Returned data is ‘None’ if no new
     messages, else value of ‘RECENT’ response.

 -- Method: IMAP4.rename (oldmailbox, newmailbox)

     Rename mailbox named 'oldmailbox' to 'newmailbox'.

 -- Method: IMAP4.response (code)

     Return data for response 'code' if received, or ‘None’.  Returns
     the given code, instead of the usual type.

 -- Method: IMAP4.search (charset, criterion[, ...])

     Search mailbox for matching messages.  'charset' may be ‘None’, in
     which case no ‘CHARSET’ will be specified in the request to the
     server.  The IMAP protocol requires that at least one criterion be
     specified; an exception will be raised when the server returns an
     error.  'charset' must be ‘None’ if the ‘UTF8=ACCEPT’ capability
     was enabled using the *note enable(): e3f. command.

     Example:

          # M is a connected IMAP4 instance...
          typ, msgnums = M.search(None, 'FROM', '"LDJ"')

          # or:
          typ, msgnums = M.search(None, '(FROM "LDJ")')

 -- Method: IMAP4.select (mailbox='INBOX', readonly=False)

     Select a mailbox.  Returned data is the count of messages in
     'mailbox' (‘EXISTS’ response).  The default 'mailbox' is ‘'INBOX'’.
     If the 'readonly' flag is set, modifications to the mailbox are not
     allowed.

 -- Method: IMAP4.send (data)

     Sends ‘data’ to the remote server.  You may override this method.

     Raises an *note auditing event: 1a15. ‘imaplib.send’ with arguments
     ‘self’, ‘data’.

 -- Method: IMAP4.setacl (mailbox, who, what)

     Set an ‘ACL’ for 'mailbox'.  The method is non-standard, but is
     supported by the ‘Cyrus’ server.

 -- Method: IMAP4.setannotation (mailbox, entry, attribute[, ...])

     Set ‘ANNOTATION’s for 'mailbox'.  The method is non-standard, but
     is supported by the ‘Cyrus’ server.

 -- Method: IMAP4.setquota (root, limits)

     Set the ‘quota’ 'root'’s resource 'limits'.  This method is part of
     the IMAP4 QUOTA extension defined in rfc2087.

 -- Method: IMAP4.shutdown ()

     Close connection established in ‘open’.  This method is implicitly
     called by *note IMAP4.logout(): aa2.  You may override this method.

 -- Method: IMAP4.socket ()

     Returns socket instance used to connect to server.

 -- Method: IMAP4.sort (sort_criteria, charset, search_criterion[, ...])

     The ‘sort’ command is a variant of ‘search’ with sorting semantics
     for the results.  Returned data contains a space separated list of
     matching message numbers.

     Sort has two arguments before the 'search_criterion' argument(s); a
     parenthesized list of 'sort_criteria', and the searching 'charset'.
     Note that unlike ‘search’, the searching 'charset' argument is
     mandatory.  There is also a ‘uid sort’ command which corresponds to
     ‘sort’ the way that ‘uid search’ corresponds to ‘search’.  The
     ‘sort’ command first searches the mailbox for messages that match
     the given searching criteria using the charset argument for the
     interpretation of strings in the searching criteria.  It then
     returns the numbers of matching messages.

     This is an ‘IMAP4rev1’ extension command.

 -- Method: IMAP4.starttls (ssl_context=None)

     Send a ‘STARTTLS’ command.  The 'ssl_context' argument is optional
     and should be a *note ssl.SSLContext: 294. object.  This will
     enable encryption on the IMAP connection.  Please read *note
     Security considerations: 3564. for best practices.

     Added in version 3.2.

     Changed in version 3.4: The method now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indication' (see *note ssl.HAS_SNI: 36a6.).

 -- Method: IMAP4.status (mailbox, names)

     Request named status conditions for 'mailbox'.

 -- Method: IMAP4.store (message_set, command, flag_list)

     Alters flag dispositions for messages in mailbox.  'command' is
     specified by section 6.4.6 of RFC 2060(5) as being one of “FLAGS”,
     “+FLAGS”, or “-FLAGS”, optionally with a suffix of “.SILENT”.

     For example, to set the delete flag on all messages:

          typ, data = M.search(None, 'ALL')
          for num in data[0].split():
             M.store(num, '+FLAGS', '\\Deleted')
          M.expunge()

          Note: Creating flags containing ‘]’ (for example: “[test]”)
          violates RFC 3501(6) (the IMAP protocol).  However, imaplib
          has historically allowed creation of such tags, and popular
          IMAP servers, such as Gmail, accept and produce such flags.
          There are non-Python programs which also create such tags.
          Although it is an RFC violation and IMAP clients and servers
          are supposed to be strict, imaplib still continues to allow
          such tags to be created for backward compatibility reasons,
          and as of Python 3.6, handles them if they are sent from the
          server, since this improves real-world compatibility.

 -- Method: IMAP4.subscribe (mailbox)

     Subscribe to new mailbox.

 -- Method: IMAP4.thread (threading_algorithm, charset,
          search_criterion[, ...])

     The ‘thread’ command is a variant of ‘search’ with threading
     semantics for the results.  Returned data contains a space
     separated list of thread members.

     Thread members consist of zero or more messages numbers, delimited
     by spaces, indicating successive parent and child.

     Thread has two arguments before the 'search_criterion' argument(s);
     a 'threading_algorithm', and the searching 'charset'.  Note that
     unlike ‘search’, the searching 'charset' argument is mandatory.
     There is also a ‘uid thread’ command which corresponds to ‘thread’
     the way that ‘uid search’ corresponds to ‘search’.  The ‘thread’
     command first searches the mailbox for messages that match the
     given searching criteria using the 'charset' argument for the
     interpretation of strings in the searching criteria.  It then
     returns the matching messages threaded according to the specified
     threading algorithm.

     This is an ‘IMAP4rev1’ extension command.

 -- Method: IMAP4.uid (command, arg[, ...])

     Execute command args with messages identified by UID, rather than
     message number.  Returns response appropriate to command.  At least
     one argument must be supplied; if none are provided, the server
     will return an error and an exception will be raised.

 -- Method: IMAP4.unsubscribe (mailbox)

     Unsubscribe from old mailbox.

 -- Method: IMAP4.unselect ()

     *note imaplib.IMAP4.unselect(): 910. frees server’s resources
     associated with the selected mailbox and returns the server to the
     authenticated state.  This command performs the same actions as
     *note imaplib.IMAP4.close(): 911, except that no messages are
     permanently removed from the currently selected mailbox.

     Added in version 3.9.

 -- Method: IMAP4.xatom (name[, ...])

     Allow simple extension commands notified by server in ‘CAPABILITY’
     response.

The following attributes are defined on instances of *note IMAP4: 90c.:

 -- Attribute: IMAP4.PROTOCOL_VERSION

     The most recent supported protocol in the ‘CAPABILITY’ response
     from the server.

 -- Attribute: IMAP4.debug

     Integer value to control debugging output.  The initialize value is
     taken from the module variable ‘Debug’.  Values greater than three
     trace each command.

 -- Attribute: IMAP4.utf8_enabled

     Boolean value that is normally ‘False’, but is set to ‘True’ if an
     *note enable(): e3f. command is successfully issued for the
     ‘UTF8=ACCEPT’ capability.

     Added in version 3.5.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5161.html

   (2) https://datatracker.ietf.org/doc/html/rfc6855.html

   (3) https://datatracker.ietf.org/doc/html/rfc6855.html

   (4) https://datatracker.ietf.org/doc/html/rfc2342.html

   (5) https://datatracker.ietf.org/doc/html/rfc2060.html

   (6) https://datatracker.ietf.org/doc/html/rfc3501.html


File: python.info,  Node: IMAP4 Example,  Prev: IMAP4 Objects,  Up: imaplib — IMAP4 protocol client

5.22.13.2 IMAP4 Example
.......................

Here is a minimal example (without error checking) that opens a mailbox
and retrieves and prints all messages:

     import getpass, imaplib

     M = imaplib.IMAP4(host='example.org')
     M.login(getpass.getuser(), getpass.getpass())
     M.select()
     typ, data = M.search(None, 'ALL')
     for num in data[0].split():
         typ, data = M.fetch(num, '(RFC822)')
         print('Message %s\n%s\n' % (num, data[0][1]))
     M.close()
     M.logout()


File: python.info,  Node: smtplib — SMTP protocol client,  Next: uuid — UUID objects according to RFC 4122,  Prev: imaplib — IMAP4 protocol client,  Up: Internet Protocols and Support

5.22.14 ‘smtplib’ — SMTP protocol client
----------------------------------------

'Source code:' Lib/smtplib.py(1)

__________________________________________________________________

The ‘smtplib’ module defines an SMTP client session object that can be
used to send mail to any internet machine with an SMTP or ESMTP listener
daemon.  For details of SMTP and ESMTP operation, consult RFC 821(2)
(Simple Mail Transfer Protocol) and RFC 1869(3) (SMTP Service
Extensions).

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

 -- Class: smtplib.SMTP (host='', port=0, local_hostname=None[,
          timeout], source_address=None)

     An ‘SMTP’ instance encapsulates an SMTP connection.  It has methods
     that support a full repertoire of SMTP and ESMTP operations.  If
     the optional 'host' and 'port' parameters are given, the SMTP *note
     connect(): 1b5a. method is called with those parameters during
     initialization.  If specified, 'local_hostname' is used as the FQDN
     of the local host in the HELO/EHLO command.  Otherwise, the local
     hostname is found using *note socket.getfqdn(): 1890.  If the
     ‘connect()’ call returns anything other than a success code, an
     *note SMTPConnectError: 3d45. is raised.  The optional 'timeout'
     parameter specifies a timeout in seconds for blocking operations
     like the connection attempt (if not specified, the global default
     timeout setting will be used).  If the timeout expires, *note
     TimeoutError: 83b. is raised.  The optional 'source_address'
     parameter allows binding to some specific source address in a
     machine with multiple network interfaces, and/or to some specific
     source TCP port.  It takes a 2-tuple ‘(host, port)’, for the socket
     to bind to as its source address before connecting.  If omitted (or
     if 'host' or 'port' are ‘''’ and/or ‘0’ respectively) the OS
     default behavior will be used.

     For normal use, you should only require the initialization/connect,
     *note sendmail(): e8d, and *note SMTP.quit(): 3d46. methods.  An
     example is included below.

     The ‘SMTP’ class supports the *note with: 5d5. statement.  When
     used like this, the SMTP ‘QUIT’ command is issued automatically
     when the ‘with’ statement exits.  E.g.:

          >>> from smtplib import SMTP
          >>> with SMTP("domain.org") as smtp:
          ...     smtp.noop()
          ...
          (250, b'Ok')
          >>>

     All commands will raise an *note auditing event: 1a15.
     ‘smtplib.SMTP.send’ with arguments ‘self’ and ‘data’, where ‘data’
     is the bytes about to be sent to the remote host.

     Changed in version 3.3: Support for the *note with: 5d5. statement
     was added.

     Changed in version 3.3: 'source_address' argument was added.

     Added in version 3.5: The SMTPUTF8 extension ( RFC 6531(4)) is now
     supported.

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket.

 -- Class: smtplib.SMTP_SSL (host='', port=0, local_hostname=None, *[,
          timeout], context=None, source_address=None)

     An ‘SMTP_SSL’ instance behaves exactly the same as instances of
     *note SMTP: 937.  ‘SMTP_SSL’ should be used for situations where
     SSL is required from the beginning of the connection and using
     *note starttls(): 117c. is not appropriate.  If 'host' is not
     specified, the local host is used.  If 'port' is zero, the standard
     SMTP-over-SSL port (465) is used.  The optional arguments
     'local_hostname', 'timeout' and 'source_address' have the same
     meaning as they do in the ‘SMTP’ class.  'context', also optional,
     can contain a *note SSLContext: 294. and allows configuring various
     aspects of the secure connection.  Please read *note Security
     considerations: 3564. for best practices.

     Changed in version 3.3: 'context' was added.

     Changed in version 3.3: The 'source_address' argument was added.

     Changed in version 3.4: The class now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indication' (see *note ssl.HAS_SNI: 36a6.).

     Changed in version 3.9: If the 'timeout' parameter is set to be
     zero, it will raise a *note ValueError: 202. to prevent the
     creation of a non-blocking socket

     Changed in version 3.12: The deprecated 'keyfile' and 'certfile'
     parameters have been removed.

 -- Class: smtplib.LMTP (host='', port=LMTP_PORT, local_hostname=None,
          source_address=None[, timeout])

     The LMTP protocol, which is very similar to ESMTP, is heavily based
     on the standard SMTP client.  It’s common to use Unix sockets for
     LMTP, so our *note connect(): 1b5a. method must support that as
     well as a regular host:port server.  The optional arguments
     'local_hostname' and 'source_address' have the same meaning as they
     do in the *note SMTP: 937. class.  To specify a Unix socket, you
     must use an absolute path for 'host', starting with a ‘/’.

     Authentication is supported, using the regular SMTP mechanism.
     When using a Unix socket, LMTP generally don’t support or require
     any authentication, but your mileage might vary.

     Changed in version 3.9: The optional 'timeout' parameter was added.

A nice selection of exceptions is defined as well:

 -- Exception: smtplib.SMTPException

     Subclass of *note OSError: 41a. that is the base exception class
     for all the other exceptions provided by this module.

     Changed in version 3.4: SMTPException became subclass of *note
     OSError: 41a.

 -- Exception: smtplib.SMTPServerDisconnected

     This exception is raised when the server unexpectedly disconnects,
     or when an attempt is made to use the *note SMTP: 937. instance
     before connecting it to a server.

 -- Exception: smtplib.SMTPResponseException

     Base class for all exceptions that include an SMTP error code.
     These exceptions are generated in some instances when the SMTP
     server returns an error code.

      -- Attribute: smtp_code

          The error code.

      -- Attribute: smtp_error

          The error message.

 -- Exception: smtplib.SMTPSenderRefused

     Sender address refused.  In addition to the attributes set by on
     all *note SMTPResponseException: 3d48. exceptions, this sets
     ‘sender’ to the string that the SMTP server refused.

 -- Exception: smtplib.SMTPRecipientsRefused

     All recipient addresses refused.

      -- Attribute: recipients

          A dictionary of exactly the same sort as returned by *note
          SMTP.sendmail(): e8d. containing the errors for each
          recipient.

 -- Exception: smtplib.SMTPDataError

     The SMTP server refused to accept the message data.

 -- Exception: smtplib.SMTPConnectError

     Error occurred during establishment of a connection with the
     server.

 -- Exception: smtplib.SMTPHeloError

     The server refused our ‘HELO’ message.

 -- Exception: smtplib.SMTPNotSupportedError

     The command or option attempted is not supported by the server.

     Added in version 3.5.

 -- Exception: smtplib.SMTPAuthenticationError

     SMTP authentication went wrong.  Most probably the server didn’t
     accept the username/password combination provided.

See also
........

RFC 821(5) - Simple Mail Transfer Protocol

     Protocol definition for SMTP. This document covers the model,
     operating procedure, and protocol details for SMTP.

RFC 1869(6) - SMTP Service Extensions

     Definition of the ESMTP extensions for SMTP. This describes a
     framework for extending SMTP with new commands, supporting dynamic
     discovery of the commands provided by the server, and defines a few
     additional commands.

* Menu:

* SMTP Objects::
* SMTP Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/smtplib.py

   (2) https://datatracker.ietf.org/doc/html/rfc821.html

   (3) https://datatracker.ietf.org/doc/html/rfc1869.html

   (4) https://datatracker.ietf.org/doc/html/rfc6531.html

   (5) https://datatracker.ietf.org/doc/html/rfc821.html

   (6) https://datatracker.ietf.org/doc/html/rfc1869.html


File: python.info,  Node: SMTP Objects,  Next: SMTP Example,  Up: smtplib — SMTP protocol client

5.22.14.1 SMTP Objects
......................

An *note SMTP: 937. instance has the following methods:

 -- Method: SMTP.set_debuglevel (level)

     Set the debug output level.  A value of 1 or ‘True’ for 'level'
     results in debug messages for connection and for all messages sent
     to and received from the server.  A value of 2 for 'level' results
     in these messages being timestamped.

     Changed in version 3.5: Added debuglevel 2.

 -- Method: SMTP.docmd (cmd, args='')

     Send a command 'cmd' to the server.  The optional argument 'args'
     is simply concatenated to the command, separated by a space.

     This returns a 2-tuple composed of a numeric response code and the
     actual response line (multiline responses are joined into one long
     line.)

     In normal operation it should not be necessary to call this method
     explicitly.  It is used to implement other methods and may be
     useful for testing private extensions.

     If the connection to the server is lost while waiting for the
     reply, *note SMTPServerDisconnected: 3d47. will be raised.

 -- Method: SMTP.connect (host='localhost', port=0)

     Connect to a host on a given port.  The defaults are to connect to
     the local host at the standard SMTP port (25).  If the hostname
     ends with a colon (‘':'’) followed by a number, that suffix will be
     stripped off and the number interpreted as the port number to use.
     This method is automatically invoked by the constructor if a host
     is specified during instantiation.  Returns a 2-tuple of the
     response code and message sent by the server in its connection
     response.

     Raises an *note auditing event: 1a15. ‘smtplib.connect’ with
     arguments ‘self’, ‘host’, ‘port’.

 -- Method: SMTP.helo (name='')

     Identify yourself to the SMTP server using ‘HELO’.  The hostname
     argument defaults to the fully qualified domain name of the local
     host.  The message returned by the server is stored as the *note
     helo_resp: 3d55. attribute of the object.

     In normal operation it should not be necessary to call this method
     explicitly.  It will be implicitly called by the *note sendmail():
     e8d. when necessary.

 -- Method: SMTP.ehlo (name='')

     Identify yourself to an ESMTP server using ‘EHLO’.  The hostname
     argument defaults to the fully qualified domain name of the local
     host.  Examine the response for ESMTP option and store them for use
     by *note has_extn(): 3d57.  Also sets several informational
     attributes: the message returned by the server is stored as the
     *note ehlo_resp: 3d58. attribute, *note does_esmtp: 3d59. is set to
     ‘True’ or ‘False’ depending on whether the server supports ESMTP,
     and *note esmtp_features: 3d5a. will be a dictionary containing the
     names of the SMTP service extensions this server supports, and
     their parameters (if any).

     Unless you wish to use *note has_extn(): 3d57. before sending mail,
     it should not be necessary to call this method explicitly.  It will
     be implicitly called by *note sendmail(): e8d. when necessary.

 -- Method: SMTP.ehlo_or_helo_if_needed ()

     This method calls *note ehlo(): 3d56. and/or *note helo(): 3d54. if
     there has been no previous ‘EHLO’ or ‘HELO’ command this session.
     It tries ESMTP ‘EHLO’ first.

     *note SMTPHeloError: 3d4f.

          The server didn’t reply properly to the ‘HELO’ greeting.

 -- Method: SMTP.has_extn (name)

     Return *note True: c2d. if 'name' is in the set of SMTP service
     extensions returned by the server, *note False: b4f. otherwise.
     Case is ignored.

 -- Method: SMTP.verify (address)

     Check the validity of an address on this server using SMTP ‘VRFY’.
     Returns a tuple consisting of code 250 and a full RFC 822(1)
     address (including human name) if the user address is valid.
     Otherwise returns an SMTP error code of 400 or greater and an error
     string.

          Note: Many sites disable SMTP ‘VRFY’ in order to foil
          spammers.

 -- Method: SMTP.login (user, password, *, initial_response_ok=True)

     Log in on an SMTP server that requires authentication.  The
     arguments are the username and the password to authenticate with.
     If there has been no previous ‘EHLO’ or ‘HELO’ command this
     session, this method tries ESMTP ‘EHLO’ first.  This method will
     return normally if the authentication was successful, or may raise
     the following exceptions:

     *note SMTPHeloError: 3d4f.

          The server didn’t reply properly to the ‘HELO’ greeting.

     *note SMTPAuthenticationError: 3d50.

          The server didn’t accept the username/password combination.

     *note SMTPNotSupportedError: 1b59.

          The ‘AUTH’ command is not supported by the server.

     *note SMTPException: fda.

          No suitable authentication method was found.

     Each of the authentication methods supported by ‘smtplib’ are tried
     in turn if they are advertised as supported by the server.  See
     *note auth(): e8b. for a list of supported authentication methods.
     'initial_response_ok' is passed through to ‘auth()’.

     Optional keyword argument 'initial_response_ok' specifies whether,
     for authentication methods that support it, an “initial response”
     as specified in RFC 4954(2) can be sent along with the ‘AUTH’
     command, rather than requiring a challenge/response.

     Changed in version 3.5: *note SMTPNotSupportedError: 1b59. may be
     raised, and the 'initial_response_ok' parameter was added.

 -- Method: SMTP.auth (mechanism, authobject, *,
          initial_response_ok=True)

     Issue an ‘SMTP’ ‘AUTH’ command for the specified authentication
     'mechanism', and handle the challenge response via 'authobject'.

     'mechanism' specifies which authentication mechanism is to be used
     as argument to the ‘AUTH’ command; the valid values are those
     listed in the ‘auth’ element of *note esmtp_features: 3d5a.

     'authobject' must be a callable object taking an optional single
     argument:

          data = authobject(challenge=None)

     If optional keyword argument 'initial_response_ok' is true,
     ‘authobject()’ will be called first with no argument.  It can
     return the RFC 4954(3) “initial response” ASCII ‘str’ which will be
     encoded and sent with the ‘AUTH’ command as below.  If the
     ‘authobject()’ does not support an initial response (e.g.  because
     it requires a challenge), it should return ‘None’ when called with
     ‘challenge=None’.  If 'initial_response_ok' is false, then
     ‘authobject()’ will not be called first with ‘None’.

     If the initial response check returns ‘None’, or if
     'initial_response_ok' is false, ‘authobject()’ will be called to
     process the server’s challenge response; the 'challenge' argument
     it is passed will be a ‘bytes’.  It should return ASCII ‘str’
     'data' that will be base64 encoded and sent to the server.

     The ‘SMTP’ class provides ‘authobjects’ for the ‘CRAM-MD5’,
     ‘PLAIN’, and ‘LOGIN’ mechanisms; they are named
     ‘SMTP.auth_cram_md5’, ‘SMTP.auth_plain’, and ‘SMTP.auth_login’
     respectively.  They all require that the ‘user’ and ‘password’
     properties of the ‘SMTP’ instance are set to appropriate values.

     User code does not normally need to call ‘auth’ directly, but can
     instead call the *note login(): 3d5d. method, which will try each
     of the above mechanisms in turn, in the order listed.  ‘auth’ is
     exposed to facilitate the implementation of authentication methods
     not (or not yet) supported directly by ‘smtplib’.

     Added in version 3.5.

 -- Method: SMTP.starttls (*, context=None)

     Put the SMTP connection in TLS (Transport Layer Security) mode.
     All SMTP commands that follow will be encrypted.  You should then
     call *note ehlo(): 3d56. again.

     If 'keyfile' and 'certfile' are provided, they are used to create
     an *note ssl.SSLContext: 294.

     Optional 'context' parameter is an *note ssl.SSLContext: 294.
     object; This is an alternative to using a keyfile and a certfile
     and if specified both 'keyfile' and 'certfile' should be ‘None’.

     If there has been no previous ‘EHLO’ or ‘HELO’ command this
     session, this method tries ESMTP ‘EHLO’ first.

     Changed in version 3.12: The deprecated 'keyfile' and 'certfile'
     parameters have been removed.

     *note SMTPHeloError: 3d4f.

          The server didn’t reply properly to the ‘HELO’ greeting.

     *note SMTPNotSupportedError: 1b59.

          The server does not support the STARTTLS extension.

     *note RuntimeError: 195.

          SSL/TLS support is not available to your Python interpreter.

     Changed in version 3.3: 'context' was added.

     Changed in version 3.4: The method now supports hostname check with
     *note ssl.SSLContext.check_hostname: 3694. and 'Server Name
     Indicator' (see *note HAS_SNI: 36a6.).

     Changed in version 3.5: The error raised for lack of STARTTLS
     support is now the *note SMTPNotSupportedError: 1b59. subclass
     instead of the base *note SMTPException: fda.

 -- Method: SMTP.sendmail (from_addr, to_addrs, msg, mail_options=(),
          rcpt_options=())

     Send mail.  The required arguments are an RFC 822(4) from-address
     string, a list of RFC 822(5) to-address strings (a bare string will
     be treated as a list with 1 address), and a message string.  The
     caller may pass a list of ESMTP options (such as ‘"8bitmime"’) to
     be used in ‘MAIL FROM’ commands as 'mail_options'.  ESMTP options
     (such as ‘DSN’ commands) that should be used with all ‘RCPT’
     commands can be passed as 'rcpt_options'.  Each option should be
     passed as a string containing the full text of the option,
     including any potential key (for instance,
     ‘"NOTIFY=SUCCESS,FAILURE"’).  (If you need to use different ESMTP
     options to different recipients you have to use the low-level
     methods such as ‘mail()’, ‘rcpt()’ and ‘data()’ to send the
     message.)

          Note: The 'from_addr' and 'to_addrs' parameters are used to
          construct the message envelope used by the transport agents.
          ‘sendmail’ does not modify the message headers in any way.

     'msg' may be a string containing characters in the ASCII range, or
     a byte string.  A string is encoded to bytes using the ascii codec,
     and lone ‘\r’ and ‘\n’ characters are converted to ‘\r\n’
     characters.  A byte string is not modified.

     If there has been no previous ‘EHLO’ or ‘HELO’ command this
     session, this method tries ESMTP ‘EHLO’ first.  If the server does
     ESMTP, message size and each of the specified options will be
     passed to it (if the option is in the feature set the server
     advertises).  If ‘EHLO’ fails, ‘HELO’ will be tried and ESMTP
     options suppressed.

     This method will return normally if the mail is accepted for at
     least one recipient.  Otherwise it will raise an exception.  That
     is, if this method does not raise an exception, then someone should
     get your mail.  If this method does not raise an exception, it
     returns a dictionary, with one entry for each recipient that was
     refused.  Each entry contains a tuple of the SMTP error code and
     the accompanying error message sent by the server.

     If ‘SMTPUTF8’ is included in 'mail_options', and the server
     supports it, 'from_addr' and 'to_addrs' may contain non-ASCII
     characters.

     This method may raise the following exceptions:

     *note SMTPRecipientsRefused: 3d4c.

          All recipients were refused.  Nobody got the mail.

     *note SMTPHeloError: 3d4f.

          The server didn’t reply properly to the ‘HELO’ greeting.

     *note SMTPSenderRefused: 3d4b.

          The server didn’t accept the 'from_addr'.

     *note SMTPDataError: 3d4e.

          The server replied with an unexpected error code (other than a
          refusal of a recipient).

     *note SMTPNotSupportedError: 1b59.

          ‘SMTPUTF8’ was given in the 'mail_options' but is not
          supported by the server.

     Unless otherwise noted, the connection will be open even after an
     exception is raised.

     Changed in version 3.2: 'msg' may be a byte string.

     Changed in version 3.5: ‘SMTPUTF8’ support added, and *note
     SMTPNotSupportedError: 1b59. may be raised if ‘SMTPUTF8’ is
     specified but the server does not support it.

 -- Method: SMTP.send_message (msg, from_addr=None, to_addrs=None,
          mail_options=(), rcpt_options=())

     This is a convenience method for calling *note sendmail(): e8d.
     with the message represented by an *note email.message.Message:
     27c. object.  The arguments have the same meaning as for
     ‘sendmail()’, except that 'msg' is a ‘Message’ object.

     If 'from_addr' is ‘None’ or 'to_addrs' is ‘None’, ‘send_message’
     fills those arguments with addresses extracted from the headers of
     'msg' as specified in RFC 5322(6): 'from_addr' is set to the
     ‘Sender’ field if it is present, and otherwise to the ‘From’ field.
     'to_addrs' combines the values (if any) of the ‘To’, ‘Cc’, and
     ‘Bcc’ fields from 'msg'.  If exactly one set of ‘Resent-*’ headers
     appear in the message, the regular headers are ignored and the
     ‘Resent-*’ headers are used instead.  If the message contains more
     than one set of ‘Resent-*’ headers, a *note ValueError: 202. is
     raised, since there is no way to unambiguously detect the most
     recent set of ‘Resent-’ headers.

     ‘send_message’ serializes 'msg' using *note BytesGenerator: 1214.
     with ‘\r\n’ as the 'linesep', and calls *note sendmail(): e8d. to
     transmit the resulting message.  Regardless of the values of
     'from_addr' and 'to_addrs', ‘send_message’ does not transmit any
     ‘Bcc’ or ‘Resent-Bcc’ headers that may appear in 'msg'.  If any of
     the addresses in 'from_addr' and 'to_addrs' contain non-ASCII
     characters and the server does not advertise ‘SMTPUTF8’ support, an
     *note SMTPNotSupportedError: 1b59. is raised.  Otherwise the
     ‘Message’ is serialized with a clone of its *note policy: 4f. with
     the *note utf8: e2a. attribute set to ‘True’, and ‘SMTPUTF8’ and
     ‘BODY=8BITMIME’ are added to 'mail_options'.

     Added in version 3.2.

     Added in version 3.5: Support for internationalized addresses
     (‘SMTPUTF8’).

 -- Method: SMTP.quit ()

     Terminate the SMTP session and close the connection.  Return the
     result of the SMTP ‘QUIT’ command.

Low-level methods corresponding to the standard SMTP/ESMTP commands
‘HELP’, ‘RSET’, ‘NOOP’, ‘MAIL’, ‘RCPT’, and ‘DATA’ are also supported.
Normally these do not need to be called directly, so they are not
documented here.  For details, consult the module code.

Additionally, an SMTP instance has the following attributes:

 -- Attribute: SMTP.helo_resp

     The response to the ‘HELO’ command, see *note helo(): 3d54.

 -- Attribute: SMTP.ehlo_resp

     The response to the ‘EHLO’ command, see *note ehlo(): 3d56.

 -- Attribute: SMTP.does_esmtp

     A boolean value indicating whether the server supports ESMTP, see
     *note ehlo(): 3d56.

 -- Attribute: SMTP.esmtp_features

     A dictionary of the names of SMTP service extensions supported by
     the server, see *note ehlo(): 3d56.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc822.html

   (2) https://datatracker.ietf.org/doc/html/rfc4954.html

   (3) https://datatracker.ietf.org/doc/html/rfc4954.html

   (4) https://datatracker.ietf.org/doc/html/rfc822.html

   (5) https://datatracker.ietf.org/doc/html/rfc822.html

   (6) https://datatracker.ietf.org/doc/html/rfc5322.html


File: python.info,  Node: SMTP Example,  Prev: SMTP Objects,  Up: smtplib — SMTP protocol client

5.22.14.2 SMTP Example
......................

This example prompts the user for addresses needed in the message
envelope (‘To’ and ‘From’ addresses), and the message to be delivered.
Note that the headers to be included with the message must be included
in the message as entered; this example doesn’t do any processing of the
RFC 822(1) headers.  In particular, the ‘To’ and ‘From’ addresses must
be included in the message headers explicitly:

     import smtplib

     def prompt(title):
         return input(title).strip()

     from_addr = prompt("From: ")
     to_addrs  = prompt("To: ").split()
     print("Enter message, end with ^D (Unix) or ^Z (Windows):")

     # Add the From: and To: headers at the start!
     lines = [f"From: {from_addr}", f"To: {', '.join(to_addrs)}", ""]
     while True:
         try:
             line = input()
         except EOFError:
             break
         else:
             lines.append(line)

     msg = "\r\n".join(lines)
     print("Message length is", len(msg))

     server = smtplib.SMTP("localhost")
     server.set_debuglevel(1)
     server.sendmail(from_addr, to_addrs, msg)
     server.quit()

     Note: In general, you will want to use the *note email: 3b.
     package’s features to construct an email message, which you can
     then send via *note send_message(): e8e.; see *note email;
     Examples: f74.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc822.html


File: python.info,  Node: uuid — UUID objects according to RFC 4122,  Next: socketserver — A framework for network servers,  Prev: smtplib — SMTP protocol client,  Up: Internet Protocols and Support

5.22.15 ‘uuid’ — UUID objects according to
------------------------------------------

'RFC 4122'

'Source code:' Lib/uuid.py(1)

__________________________________________________________________

This module provides immutable *note UUID: a6f. objects (the ‘UUID’
class) and the functions *note uuid1(): bc6, *note uuid3(): 1664, *note
uuid4(): 1665, *note uuid5(): 1666. for generating version 1, 3, 4, and
5 UUIDs as specified in RFC 4122(2).

If all you want is a unique ID, you should probably call *note uuid1():
bc6. or *note uuid4(): 1665.  Note that ‘uuid1()’ may compromise privacy
since it creates a UUID containing the computer’s network address.
‘uuid4()’ creates a random UUID.

Depending on support from the underlying platform, *note uuid1(): bc6.
may or may not return a “safe” UUID. A safe UUID is one which is
generated using synchronization methods that ensure no two processes can
obtain the same UUID. All instances of *note UUID: a6f. have an *note
is_safe: bc4. attribute which relays any information about the UUID’s
safety, using this enumeration:

 -- Class: uuid.SafeUUID

     Added in version 3.7.

      -- Attribute: safe

          The UUID was generated by the platform in a
          multiprocessing-safe way.

      -- Attribute: unsafe

          The UUID was not generated in a multiprocessing-safe way.

      -- Attribute: unknown

          The platform does not provide information on whether the UUID
          was generated safely or not.

 -- Class: uuid.UUID (hex=None, bytes=None, bytes_le=None, fields=None,
          int=None, version=None, *, is_safe=SafeUUID.unknown)

     Create a UUID from either a string of 32 hexadecimal digits, a
     string of 16 bytes in big-endian order as the 'bytes' argument, a
     string of 16 bytes in little-endian order as the 'bytes_le'
     argument, a tuple of six integers (32-bit 'time_low', 16-bit
     'time_mid', 16-bit 'time_hi_version', 8-bit 'clock_seq_hi_variant',
     8-bit 'clock_seq_low', 48-bit 'node') as the 'fields' argument, or
     a single 128-bit integer as the 'int' argument.  When a string of
     hex digits is given, curly braces, hyphens, and a URN prefix are
     all optional.  For example, these expressions all yield the same
     UUID:

          UUID('{12345678-1234-5678-1234-567812345678}')
          UUID('12345678123456781234567812345678')
          UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
          UUID(bytes=b'\x12\x34\x56\x78'*4)
          UUID(bytes_le=b'\x78\x56\x34\x12\x34\x12\x78\x56' +
                        b'\x12\x34\x56\x78\x12\x34\x56\x78')
          UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
          UUID(int=0x12345678123456781234567812345678)

     Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
     be given.  The 'version' argument is optional; if given, the
     resulting UUID will have its variant and version number set
     according to RFC 4122(3), overriding bits in the given 'hex',
     'bytes', 'bytes_le', 'fields', or 'int'.

     Comparison of UUID objects are made by way of comparing their *note
     UUID.int: 3d67. attributes.  Comparison with a non-UUID object
     raises a *note TypeError: 2c3.

     ‘str(uuid)’ returns a string in the form
     ‘12345678-1234-5678-1234-567812345678’ where the 32 hexadecimal
     digits represent the UUID.

*note UUID: a6f. instances have these read-only attributes:

 -- Attribute: UUID.bytes

     The UUID as a 16-byte string (containing the six integer fields in
     big-endian byte order).

 -- Attribute: UUID.bytes_le

     The UUID as a 16-byte string (with 'time_low', 'time_mid', and
     'time_hi_version' in little-endian byte order).

 -- Attribute: UUID.fields

     A tuple of the six integer fields of the UUID, which are also
     available as six individual attributes and two derived attributes:

Field                                                  Meaning
                                                       
                                                       
 -- Attribute: UUID.time_low                           The first 32 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.time_mid                           The next 16 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.time_hi_version                    The next 16 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.clock_seq_hi_variant               The next 8 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.clock_seq_low                      The next 8 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.node                               The last 48 bits of the UUID.
                                                       
                                                       
 -- Attribute: UUID.time                               The 60-bit timestamp.
                                                       
                                                       
 -- Attribute: UUID.clock_seq                          The 14-bit sequence number.
                                                       

 -- Attribute: UUID.hex

     The UUID as a 32-character lowercase hexadecimal string.

 -- Attribute: UUID.int

     The UUID as a 128-bit integer.

 -- Attribute: UUID.urn

     The UUID as a URN as specified in RFC 4122(4).

 -- Attribute: UUID.variant

     The UUID variant, which determines the internal layout of the UUID.
     This will be one of the constants *note RESERVED_NCS: 3d76, *note
     RFC_4122: 3d77, *note RESERVED_MICROSOFT: 3d78, or *note
     RESERVED_FUTURE: 3d79.

 -- Attribute: UUID.version

     The UUID version number (1 through 5, meaningful only when the
     variant is *note RFC_4122: 3d77.).

 -- Attribute: UUID.is_safe

     An enumeration of *note SafeUUID: 3d63. which indicates whether the
     platform generated the UUID in a multiprocessing-safe way.

     Added in version 3.7.

The ‘uuid’ module defines the following functions:

 -- Function: uuid.getnode ()

     Get the hardware address as a 48-bit positive integer.  The first
     time this runs, it may launch a separate program, which could be
     quite slow.  If all attempts to obtain the hardware address fail,
     we choose a random 48-bit number with the multicast bit (least
     significant bit of the first octet) set to 1 as recommended in RFC
     4122(5).  “Hardware address” means the MAC address of a network
     interface.  On a machine with multiple network interfaces,
     universally administered MAC addresses (i.e.  where the second
     least significant bit of the first octet is 'unset') will be
     preferred over locally administered MAC addresses, but with no
     other ordering guarantees.

     Changed in version 3.7: Universally administered MAC addresses are
     preferred over locally administered MAC addresses, since the former
     are guaranteed to be globally unique, while the latter are not.

 -- Function: uuid.uuid1 (node=None, clock_seq=None)

     Generate a UUID from a host ID, sequence number, and the current
     time.  If 'node' is not given, *note getnode(): bc5. is used to
     obtain the hardware address.  If 'clock_seq' is given, it is used
     as the sequence number; otherwise a random 14-bit sequence number
     is chosen.

 -- Function: uuid.uuid3 (namespace, name)

     Generate a UUID based on the MD5 hash of a namespace identifier
     (which is a UUID) and a name (which is a *note bytes: 1c2. object
     or a string that will be encoded using UTF-8).

 -- Function: uuid.uuid4 ()

     Generate a random UUID.

 -- Function: uuid.uuid5 (namespace, name)

     Generate a UUID based on the SHA-1 hash of a namespace identifier
     (which is a UUID) and a name (which is a *note bytes: 1c2. object
     or a string that will be encoded using UTF-8).

The ‘uuid’ module defines the following namespace identifiers for use
with *note uuid3(): 1664. or *note uuid5(): 1666.

 -- Data: uuid.NAMESPACE_DNS

     When this namespace is specified, the 'name' string is a fully
     qualified domain name.

 -- Data: uuid.NAMESPACE_URL

     When this namespace is specified, the 'name' string is a URL.

 -- Data: uuid.NAMESPACE_OID

     When this namespace is specified, the 'name' string is an ISO OID.

 -- Data: uuid.NAMESPACE_X500

     When this namespace is specified, the 'name' string is an X.500 DN
     in DER or a text output format.

The ‘uuid’ module defines the following constants for the possible
values of the *note variant: 3d75. attribute:

 -- Data: uuid.RESERVED_NCS

     Reserved for NCS compatibility.

 -- Data: uuid.RFC_4122

     Specifies the UUID layout given in RFC 4122(6).

 -- Data: uuid.RESERVED_MICROSOFT

     Reserved for Microsoft compatibility.

 -- Data: uuid.RESERVED_FUTURE

     Reserved for future definition.

See also
........

RFC 4122(7) - A Universally Unique IDentifier (UUID) URN Namespace

     This specification defines a Uniform Resource Name namespace for
     UUIDs, the internal format of UUIDs, and methods of generating
     UUIDs.

* Menu:

* Command-Line Usage: Command-Line Usage<2>.
* Example: Example<11>.
* Command-Line Example::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/uuid.py

   (2) https://datatracker.ietf.org/doc/html/rfc4122.html

   (3) https://datatracker.ietf.org/doc/html/rfc4122.html

   (4) https://datatracker.ietf.org/doc/html/rfc4122.html

   (5) https://datatracker.ietf.org/doc/html/rfc4122.html

   (6) https://datatracker.ietf.org/doc/html/rfc4122.html

   (7) https://datatracker.ietf.org/doc/html/rfc4122.html


File: python.info,  Node: Command-Line Usage<2>,  Next: Example<11>,  Up: uuid — UUID objects according to RFC 4122

5.22.15.1 Command-Line Usage
............................

Added in version 3.12.

The ‘uuid’ module can be executed as a script from the command line.

     python -m uuid [-h] [-u {uuid1,uuid3,uuid4,uuid5}] [-n NAMESPACE] [-N NAME]

The following options are accepted:

 -- Option: -h, --help

     Show the help message and exit.

 -- Option: -u <uuid>
 -- Option: --uuid <uuid>

     Specify the function name to use to generate the uuid.  By default
     *note uuid4(): 1665. is used.

 -- Option: -n <namespace>
 -- Option: --namespace <namespace>

     The namespace is a ‘UUID’, or ‘@ns’ where ‘ns’ is a well-known
     predefined UUID addressed by namespace name.  Such as ‘@dns’,
     ‘@url’, ‘@oid’, and ‘@x500’.  Only required for *note uuid3():
     1664. / *note uuid5(): 1666. functions.

 -- Option: -N <name>
 -- Option: --name <name>

     The name used as part of generating the uuid.  Only required for
     *note uuid3(): 1664. / *note uuid5(): 1666. functions.


File: python.info,  Node: Example<11>,  Next: Command-Line Example,  Prev: Command-Line Usage<2>,  Up: uuid — UUID objects according to RFC 4122

5.22.15.2 Example
.................

Here are some examples of typical usage of the ‘uuid’ module:

     >>> import uuid

     >>> # make a UUID based on the host ID and current time
     >>> uuid.uuid1()
     UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')

     >>> # make a UUID using an MD5 hash of a namespace UUID and a name
     >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
     UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')

     >>> # make a random UUID
     >>> uuid.uuid4()
     UUID('16fd2706-8baf-433b-82eb-8c7fada847da')

     >>> # make a UUID using a SHA-1 hash of a namespace UUID and a name
     >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
     UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')

     >>> # make a UUID from a string of hex digits (braces and hyphens ignored)
     >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')

     >>> # convert a UUID to a string of hex digits in standard form
     >>> str(x)
     '00010203-0405-0607-0809-0a0b0c0d0e0f'

     >>> # get the raw 16 bytes of the UUID
     >>> x.bytes
     b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'

     >>> # make a UUID from a 16-byte string
     >>> uuid.UUID(bytes=x.bytes)
     UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')


File: python.info,  Node: Command-Line Example,  Prev: Example<11>,  Up: uuid — UUID objects according to RFC 4122

5.22.15.3 Command-Line Example
..............................

Here are some examples of typical usage of the ‘uuid’ command line
interface:

     # generate a random uuid - by default uuid4() is used
     $ python -m uuid

     # generate a uuid using uuid1()
     $ python -m uuid -u uuid1

     # generate a uuid using uuid5
     $ python -m uuid -u uuid5 -n @url -N example.com


File: python.info,  Node: socketserver — A framework for network servers,  Next: http server — HTTP servers,  Prev: uuid — UUID objects according to RFC 4122,  Up: Internet Protocols and Support

5.22.16 ‘socketserver’ — A framework for network servers
--------------------------------------------------------

'Source code:' Lib/socketserver.py(1)

__________________________________________________________________

The ‘socketserver’ module simplifies the task of writing network
servers.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

There are four basic concrete server classes:

 -- Class: socketserver.TCPServer (server_address, RequestHandlerClass,
          bind_and_activate=True)

     This uses the internet TCP protocol, which provides for continuous
     streams of data between the client and server.  If
     'bind_and_activate' is true, the constructor automatically attempts
     to invoke *note server_bind(): 3d8f. and *note server_activate():
     3d90.  The other parameters are passed to the *note BaseServer:
     1181. base class.

 -- Class: socketserver.UDPServer (server_address, RequestHandlerClass,
          bind_and_activate=True)

     This uses datagrams, which are discrete packets of information that
     may arrive out of order or be lost while in transit.  The
     parameters are the same as for *note TCPServer: 1369.

 -- Class: socketserver.UnixStreamServer (server_address,
          RequestHandlerClass, bind_and_activate=True)
 -- Class: socketserver.UnixDatagramServer (server_address,
          RequestHandlerClass, bind_and_activate=True)

     These more infrequently used classes are similar to the TCP and UDP
     classes, but use Unix domain sockets; they’re not available on
     non-Unix platforms.  The parameters are the same as for *note
     TCPServer: 1369.

These four classes process requests 'synchronously'; each request must
be completed before the next request can be started.  This isn’t
suitable if each request takes a long time to complete, because it
requires a lot of computation, or because it returns a lot of data which
the client is slow to process.  The solution is to create a separate
process or thread to handle each request; the *note ForkingMixIn: b96.
and *note ThreadingMixIn: b5e. mix-in classes can be used to support
asynchronous behaviour.

Creating a server requires several steps.  First, you must create a
request handler class by subclassing the *note BaseRequestHandler: 3d94.
class and overriding its *note handle(): 3d95. method; this method will
process incoming requests.  Second, you must instantiate one of the
server classes, passing it the server’s address and the request handler
class.  It is recommended to use the server in a *note with: 5d5.
statement.  Then call the *note handle_request(): 136c. or *note
serve_forever(): 1183. method of the server object to process one or
many requests.  Finally, call *note server_close(): b94. to close the
socket (unless you used a ‘with’ statement).

When inheriting from *note ThreadingMixIn: b5e. for threaded connection
behavior, you should explicitly declare how you want your threads to
behave on an abrupt shutdown.  The ‘ThreadingMixIn’ class defines an
attribute 'daemon_threads', which indicates whether or not the server
should wait for thread termination.  You should set the flag explicitly
if you would like threads to behave autonomously; the default is *note
False: b4f, meaning that Python will not exit until all threads created
by ‘ThreadingMixIn’ have exited.

Server classes have the same external methods and attributes, no matter
what network protocol they use.

* Menu:

* Server Creation Notes::
* Server Objects::
* Request Handler Objects::
* Examples: Examples<28>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/socketserver.py


File: python.info,  Node: Server Creation Notes,  Next: Server Objects,  Up: socketserver — A framework for network servers

5.22.16.1 Server Creation Notes
...............................

There are five classes in an inheritance diagram, four of which
represent synchronous servers of four types:

     +------------+
     | BaseServer |
     +------------+
           |
           v
     +-----------+        +------------------+
     | TCPServer |------->| UnixStreamServer |
     +-----------+        +------------------+
           |
           v
     +-----------+        +--------------------+
     | UDPServer |------->| UnixDatagramServer |
     +-----------+        +--------------------+

Note that *note UnixDatagramServer: 3d93. derives from *note UDPServer:
3d91, not from *note UnixStreamServer: 3d92. — the only difference
between an IP and a Unix server is the address family.

 -- Class: socketserver.ForkingMixIn
 -- Class: socketserver.ThreadingMixIn

     Forking and threading versions of each type of server can be
     created using these mix-in classes.  For instance, *note
     ThreadingUDPServer: 3d97. is created as follows:

          class ThreadingUDPServer(ThreadingMixIn, UDPServer):
              pass

     The mix-in class comes first, since it overrides a method defined
     in *note UDPServer: 3d91.  Setting the various attributes also
     changes the behavior of the underlying server mechanism.

     ‘ForkingMixIn’ and the Forking classes mentioned below are only
     available on POSIX platforms that support *note fork(): 197.

      -- Attribute: block_on_close

          *note ForkingMixIn.server_close: b94. waits until all child
          processes complete, except if *note block_on_close: b95.
          attribute is ‘False’.

          *note ThreadingMixIn.server_close: b94. waits until all
          non-daemon threads complete, except if *note block_on_close:
          b95. attribute is ‘False’.

      -- Attribute: daemon_threads

          For ‘ThreadingMixIn’ use daemonic threads by setting *note
          ThreadingMixIn.daemon_threads: 3d98. to ‘True’ to not wait
          until threads complete.

     Changed in version 3.7: *note ForkingMixIn.server_close: b94. and
     ‘ThreadingMixIn.server_close’ now waits until all child processes
     and non-daemonic threads complete.  Add a new *note
     ForkingMixIn.block_on_close: b95. class attribute to opt-in for the
     pre-3.7 behaviour.

 -- Class: socketserver.ForkingTCPServer
 -- Class: socketserver.ForkingUDPServer
 -- Class: socketserver.ThreadingTCPServer
 -- Class: socketserver.ThreadingUDPServer
 -- Class: socketserver.ForkingUnixStreamServer
 -- Class: socketserver.ForkingUnixDatagramServer
 -- Class: socketserver.ThreadingUnixStreamServer
 -- Class: socketserver.ThreadingUnixDatagramServer

     These classes are pre-defined using the mix-in classes.

Added in version 3.12: The ‘ForkingUnixStreamServer’ and
‘ForkingUnixDatagramServer’ classes were added.

To implement a service, you must derive a class from *note
BaseRequestHandler: 3d94. and redefine its *note handle(): 3d95. method.
You can then run various versions of the service by combining one of the
server classes with your request handler class.  The request handler
class must be different for datagram or stream services.  This can be
hidden by using the handler subclasses *note StreamRequestHandler: d01.
or *note DatagramRequestHandler: 3da0.

Of course, you still have to use your head!  For instance, it makes no
sense to use a forking server if the service contains state in memory
that can be modified by different requests, since the modifications in
the child process would never reach the initial state kept in the parent
process and passed to each child.  In this case, you can use a threading
server, but you will probably have to use locks to protect the integrity
of the shared data.

On the other hand, if you are building an HTTP server where all data is
stored externally (for instance, in the file system), a synchronous
class will essentially render the service “deaf” while one request is
being handled – which may be for a very long time if a client is slow to
receive all the data it has requested.  Here a threading or forking
server is appropriate.

In some cases, it may be appropriate to process part of a request
synchronously, but to finish processing in a forked child depending on
the request data.  This can be implemented by using a synchronous server
and doing an explicit fork in the request handler class *note handle():
3d95. method.

Another approach to handling multiple simultaneous requests in an
environment that supports neither threads nor *note fork(): 197. (or
where these are too expensive or inappropriate for the service) is to
maintain an explicit table of partially finished requests and to use
*note selectors: c2. to decide which request to work on next (or whether
to handle a new incoming request).  This is particularly important for
stream services where each client can potentially be connected for a
long time (if threads or subprocesses cannot be used).


File: python.info,  Node: Server Objects,  Next: Request Handler Objects,  Prev: Server Creation Notes,  Up: socketserver — A framework for network servers

5.22.16.2 Server Objects
........................

 -- Class: socketserver.BaseServer (server_address, RequestHandlerClass)

     This is the superclass of all Server objects in the module.  It
     defines the interface, given below, but does not implement most of
     the methods, which is done in subclasses.  The two parameters are
     stored in the respective *note server_address: 3da2. and *note
     RequestHandlerClass: 3da3. attributes.

      -- Method: fileno ()

          Return an integer file descriptor for the socket on which the
          server is listening.  This function is most commonly passed to
          *note selectors: c2, to allow monitoring multiple servers in
          the same process.

      -- Method: handle_request ()

          Process a single request.  This function calls the following
          methods in order: *note get_request(): 3da5, *note
          verify_request(): 3da6, and *note process_request(): 3da7.  If
          the user-provided *note handle(): 3d95. method of the handler
          class raises an exception, the server’s *note handle_error():
          d6a. method will be called.  If no request is received within
          *note timeout: 136a. seconds, *note handle_timeout(): 136b.
          will be called and ‘handle_request()’ will return.

      -- Method: serve_forever (poll_interval=0.5)

          Handle requests until an explicit *note shutdown(): 1bc5.
          request.  Poll for shutdown every 'poll_interval' seconds.
          Ignores the *note timeout: 136a. attribute.  It also calls
          *note service_actions(): 1182, which may be used by a subclass
          or mixin to provide actions specific to a given service.  For
          example, the *note ForkingMixIn: b96. class uses
          ‘service_actions()’ to clean up zombie child processes.

          Changed in version 3.3: Added ‘service_actions’ call to the
          ‘serve_forever’ method.

      -- Method: service_actions ()

          This is called in the *note serve_forever(): 1183. loop.  This
          method can be overridden by subclasses or mixin classes to
          perform actions specific to a given service, such as cleanup
          actions.

          Added in version 3.3.

      -- Method: shutdown ()

          Tell the *note serve_forever(): 1183. loop to stop and wait
          until it does.  ‘shutdown()’ must be called while
          ‘serve_forever()’ is running in a different thread otherwise
          it will deadlock.

      -- Method: server_close ()

          Clean up the server.  May be overridden.

      -- Attribute: address_family

          The family of protocols to which the server’s socket belongs.
          Common examples are *note socket.AF_INET: 1953, *note
          socket.AF_INET6: 1954, and *note socket.AF_UNIX: 1955.
          Subclass the TCP or UDP server classes in this module with
          class attribute ‘address_family = AF_INET6’ set if you want
          IPv6 server classes.

      -- Attribute: RequestHandlerClass

          The user-provided request handler class; an instance of this
          class is created for each request.

      -- Attribute: server_address

          The address on which the server is listening.  The format of
          addresses varies depending on the protocol family; see the
          documentation for the *note socket: cc. module for details.
          For internet protocols, this is a tuple containing a string
          giving the address, and an integer port number: ‘('127.0.0.1',
          80)’, for example.

      -- Attribute: socket

          The socket object on which the server will listen for incoming
          requests.

     The server classes support the following class variables:

      -- Attribute: allow_reuse_address

          Whether the server will allow the reuse of an address.  This
          defaults to *note False: b4f, and can be set in subclasses to
          change the policy.

      -- Attribute: request_queue_size

          The size of the request queue.  If it takes a long time to
          process a single request, any requests that arrive while the
          server is busy are placed into a queue, up to *note
          request_queue_size: 3dab. requests.  Once the queue is full,
          further requests from clients will get a “Connection denied”
          error.  The default value is usually 5, but this can be
          overridden by subclasses.

      -- Attribute: socket_type

          The type of socket used by the server; *note
          socket.SOCK_STREAM: 133c. and *note socket.SOCK_DGRAM: 133b.
          are two common values.

      -- Attribute: timeout

          Timeout duration, measured in seconds, or *note None: 678. if
          no timeout is desired.  If *note handle_request(): 136c.
          receives no incoming requests within the timeout period, the
          *note handle_timeout(): 136b. method is called.

     There are various server methods that can be overridden by
     subclasses of base server classes like *note TCPServer: 1369.;
     these methods aren’t useful to external users of the server object.

      -- Method: finish_request (request, client_address)

          Actually processes the request by instantiating *note
          RequestHandlerClass: 3da3. and calling its *note handle():
          3d95. method.

      -- Method: get_request ()

          Must accept a request from the socket, and return a 2-tuple
          containing the 'new' socket object to be used to communicate
          with the client, and the client’s address.

      -- Method: handle_error (request, client_address)

          This function is called if the *note handle(): 3d95. method of
          a *note RequestHandlerClass: 3da3. instance raises an
          exception.  The default action is to print the traceback to
          standard error and continue handling further requests.

          Changed in version 3.6: Now only called for exceptions derived
          from the *note Exception: 9e5. class.

      -- Method: handle_timeout ()

          This function is called when the *note timeout: 136a.
          attribute has been set to a value other than *note None: 678.
          and the timeout period has passed with no requests being
          received.  The default action for forking servers is to
          collect the status of any child processes that have exited,
          while in threading servers this method does nothing.

      -- Method: process_request (request, client_address)

          Calls *note finish_request(): 3dad. to create an instance of
          the *note RequestHandlerClass: 3da3.  If desired, this
          function can create a new process or thread to handle the
          request; the *note ForkingMixIn: b96. and *note
          ThreadingMixIn: b5e. classes do this.

      -- Method: server_activate ()

          Called by the server’s constructor to activate the server.
          The default behavior for a TCP server just invokes *note
          listen(): e92. on the server’s socket.  May be overridden.

      -- Method: server_bind ()

          Called by the server’s constructor to bind the socket to the
          desired address.  May be overridden.

      -- Method: verify_request (request, client_address)

          Must return a Boolean value; if the value is *note True: c2d,
          the request will be processed, and if it’s *note False: b4f,
          the request will be denied.  This function can be overridden
          to implement access controls for a server.  The default
          implementation always returns ‘True’.

     Changed in version 3.6: Support for the *note context manager: 5d7.
     protocol was added.  Exiting the context manager is equivalent to
     calling *note server_close(): b94.


File: python.info,  Node: Request Handler Objects,  Next: Examples<28>,  Prev: Server Objects,  Up: socketserver — A framework for network servers

5.22.16.3 Request Handler Objects
.................................

 -- Class: socketserver.BaseRequestHandler

     This is the superclass of all request handler objects.  It defines
     the interface, given below.  A concrete request handler subclass
     must define a new *note handle(): 3d95. method, and can override
     any of the other methods.  A new instance of the subclass is
     created for each request.

      -- Method: setup ()

          Called before the *note handle(): 3d95. method to perform any
          initialization actions required.  The default implementation
          does nothing.

      -- Method: handle ()

          This function must do all the work required to service a
          request.  The default implementation does nothing.  Several
          instance attributes are available to it; the request is
          available as *note request: 3db0.; the client address as *note
          client_address: 3db1.; and the server instance as *note
          server: 3db2, in case it needs access to per-server
          information.

          The type of *note request: 3db0. is different for datagram or
          stream services.  For stream services, ‘request’ is a socket
          object; for datagram services, ‘request’ is a pair of string
          and socket.

      -- Method: finish ()

          Called after the *note handle(): 3d95. method to perform any
          clean-up actions required.  The default implementation does
          nothing.  If *note setup(): 3daf. raises an exception, this
          function will not be called.

      -- Attribute: request

          The 'new' *note socket.socket: dcf. object to be used to
          communicate with the client.

      -- Attribute: client_address

          Client address returned by *note BaseServer.get_request():
          3da5.

      -- Attribute: server

          *note BaseServer: 1181. object used for handling the request.

 -- Class: socketserver.StreamRequestHandler
 -- Class: socketserver.DatagramRequestHandler

     These *note BaseRequestHandler: 3d94. subclasses override the *note
     setup(): 3daf. and *note finish(): 3db3. methods, and provide *note
     rfile: 3db4. and *note wfile: d00. attributes.

      -- Attribute: rfile

          A file object from which receives the request is read.
          Support the *note io.BufferedIOBase: 697. readable interface.

      -- Attribute: wfile

          A file object to which the reply is written.  Support the
          *note io.BufferedIOBase: 697. writable interface

     Changed in version 3.6: *note wfile: d00. also supports the *note
     io.BufferedIOBase: 697. writable interface.


File: python.info,  Node: Examples<28>,  Prev: Request Handler Objects,  Up: socketserver — A framework for network servers

5.22.16.4 Examples
..................

* Menu:

* socketserver.TCPServer Example: socketserver TCPServer Example.
* socketserver.UDPServer Example: socketserver UDPServer Example.
* Asynchronous Mixins::


File: python.info,  Node: socketserver TCPServer Example,  Next: socketserver UDPServer Example,  Up: Examples<28>

5.22.16.5 ‘socketserver.TCPServer’ Example
..........................................

This is the server side:

     import socketserver

     class MyTCPHandler(socketserver.BaseRequestHandler):
         """
         The request handler class for our server.

         It is instantiated once per connection to the server, and must
         override the handle() method to implement communication to the
         client.
         """

         def handle(self):
             # self.request is the TCP socket connected to the client
             pieces = [b'']
             total = 0
             while b'\n' not in pieces[-1] and total < 10_000:
                 pieces.append(self.request.recv(2000))
                 total += len(pieces[-1])
             self.data = b''.join(pieces)
             print(f"Received from {self.client_address[0]}:")
             print(self.data.decode("utf-8"))
             # just send back the same data, but upper-cased
             self.request.sendall(self.data.upper())
             # after we return, the socket will be closed.

     if __name__ == "__main__":
         HOST, PORT = "localhost", 9999

         # Create the server, binding to localhost on port 9999
         with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server:
             # Activate the server; this will keep running until you
             # interrupt the program with Ctrl-C
             server.serve_forever()

An alternative request handler class that makes use of streams
(file-like objects that simplify communication by providing the standard
file interface):

     class MyTCPHandler(socketserver.StreamRequestHandler):

         def handle(self):
             # self.rfile is a file-like object created by the handler.
             # We can now use e.g. readline() instead of raw recv() calls.
             # We limit ourselves to 10000 bytes to avoid abuse by the sender.
             self.data = self.rfile.readline(10000).rstrip()
             print(f"{self.client_address[0]} wrote:")
             print(self.data.decode("utf-8"))
             # Likewise, self.wfile is a file-like object used to write back
             # to the client
             self.wfile.write(self.data.upper())

The difference is that the ‘readline()’ call in the second handler will
call ‘recv()’ multiple times until it encounters a newline character,
while the first handler had to use a ‘recv()’ loop to accumulate data
until a newline itself.  If it had just used a single ‘recv()’ without
the loop it would just have returned what has been received so far from
the client.  TCP is stream based: data arrives in the order it was sent,
but there is no correlation between client ‘send()’ or ‘sendall()’ calls
and the number of ‘recv()’ calls on the server required to receive it.

This is the client side:

     import socket
     import sys

     HOST, PORT = "localhost", 9999
     data = " ".join(sys.argv[1:])

     # Create a socket (SOCK_STREAM means a TCP socket)
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
         # Connect to server and send data
         sock.connect((HOST, PORT))
         sock.sendall(bytes(data, "utf-8"))
         sock.sendall(b"\n")

         # Receive data from the server and shut down
         received = str(sock.recv(1024), "utf-8")

     print("Sent:    ", data)
     print("Received:", received)

The output of the example should look something like this:

Server:

     $ python TCPServer.py
     127.0.0.1 wrote:
     b'hello world with TCP'
     127.0.0.1 wrote:
     b'python is nice'

Client:

     $ python TCPClient.py hello world with TCP
     Sent:     hello world with TCP
     Received: HELLO WORLD WITH TCP
     $ python TCPClient.py python is nice
     Sent:     python is nice
     Received: PYTHON IS NICE


File: python.info,  Node: socketserver UDPServer Example,  Next: Asynchronous Mixins,  Prev: socketserver TCPServer Example,  Up: Examples<28>

5.22.16.6 ‘socketserver.UDPServer’ Example
..........................................

This is the server side:

     import socketserver

     class MyUDPHandler(socketserver.BaseRequestHandler):
         """
         This class works similar to the TCP handler class, except that
         self.request consists of a pair of data and client socket, and since
         there is no connection the client address must be given explicitly
         when sending data back via sendto().
         """

         def handle(self):
             data = self.request[0].strip()
             socket = self.request[1]
             print(f"{self.client_address[0]} wrote:")
             print(data)
             socket.sendto(data.upper(), self.client_address)

     if __name__ == "__main__":
         HOST, PORT = "localhost", 9999
         with socketserver.UDPServer((HOST, PORT), MyUDPHandler) as server:
             server.serve_forever()

This is the client side:

     import socket
     import sys

     HOST, PORT = "localhost", 9999
     data = " ".join(sys.argv[1:])

     # SOCK_DGRAM is the socket type to use for UDP sockets
     sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

     # As you can see, there is no connect() call; UDP has no connections.
     # Instead, data is directly sent to the recipient via sendto().
     sock.sendto(bytes(data + "\n", "utf-8"), (HOST, PORT))
     received = str(sock.recv(1024), "utf-8")

     print("Sent:    ", data)
     print("Received:", received)

The output of the example should look exactly like for the TCP server
example.


File: python.info,  Node: Asynchronous Mixins,  Prev: socketserver UDPServer Example,  Up: Examples<28>

5.22.16.7 Asynchronous Mixins
.............................

To build asynchronous handlers, use the *note ThreadingMixIn: b5e. and
*note ForkingMixIn: b96. classes.

An example for the *note ThreadingMixIn: b5e. class:

     import socket
     import threading
     import socketserver

     class ThreadedTCPRequestHandler(socketserver.BaseRequestHandler):

         def handle(self):
             data = str(self.request.recv(1024), 'ascii')
             cur_thread = threading.current_thread()
             response = bytes("{}: {}".format(cur_thread.name, data), 'ascii')
             self.request.sendall(response)

     class ThreadedTCPServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
         pass

     def client(ip, port, message):
         with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
             sock.connect((ip, port))
             sock.sendall(bytes(message, 'ascii'))
             response = str(sock.recv(1024), 'ascii')
             print("Received: {}".format(response))

     if __name__ == "__main__":
         # Port 0 means to select an arbitrary unused port
         HOST, PORT = "localhost", 0

         server = ThreadedTCPServer((HOST, PORT), ThreadedTCPRequestHandler)
         with server:
             ip, port = server.server_address

             # Start a thread with the server -- that thread will then start one
             # more thread for each request
             server_thread = threading.Thread(target=server.serve_forever)
             # Exit the server thread when the main thread terminates
             server_thread.daemon = True
             server_thread.start()
             print("Server loop running in thread:", server_thread.name)

             client(ip, port, "Hello World 1")
             client(ip, port, "Hello World 2")
             client(ip, port, "Hello World 3")

             server.shutdown()

The output of the example should look something like this:

     $ python ThreadedTCPServer.py
     Server loop running in thread: Thread-1
     Received: Thread-2: Hello World 1
     Received: Thread-3: Hello World 2
     Received: Thread-4: Hello World 3

The *note ForkingMixIn: b96. class is used in the same way, except that
the server will spawn a new process for each request.  Available only on
POSIX platforms that support *note fork(): 197.


File: python.info,  Node: http server — HTTP servers,  Next: http cookies — HTTP state management,  Prev: socketserver — A framework for network servers,  Up: Internet Protocols and Support

5.22.17 ‘http.server’ — HTTP servers
------------------------------------

'Source code:' Lib/http/server.py(1)

__________________________________________________________________

This module defines classes for implementing HTTP servers.

     Warning: ‘http.server’ is not recommended for production.  It only
     implements *note basic security checks: 3dbc.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

One class, *note HTTPServer: 3bb3, is a *note socketserver.TCPServer:
1369. subclass.  It creates and listens at the HTTP socket, dispatching
the requests to a handler.  Code to create and run the server looks like
this:

     def run(server_class=HTTPServer, handler_class=BaseHTTPRequestHandler):
         server_address = ('', 8000)
         httpd = server_class(server_address, handler_class)
         httpd.serve_forever()

 -- Class: http.server.HTTPServer (server_address, RequestHandlerClass)

     This class builds on the *note TCPServer: 1369. class by storing
     the server address as instance variables named ‘server_name’ and
     ‘server_port’.  The server is accessible by the handler, typically
     through the handler’s ‘server’ instance variable.

 -- Class: http.server.ThreadingHTTPServer (server_address,
          RequestHandlerClass)

     This class is identical to HTTPServer but uses threads to handle
     requests by using the *note ThreadingMixIn: b5e.  This is useful to
     handle web browsers pre-opening sockets, on which *note HTTPServer:
     3bb3. would wait indefinitely.

     Added in version 3.7.

The *note HTTPServer: 3bb3. and *note ThreadingHTTPServer: b5d. must be
given a 'RequestHandlerClass' on instantiation, of which this module
provides three different variants:

 -- Class: http.server.BaseHTTPRequestHandler (request, client_address,
          server)

     This class is used to handle the HTTP requests that arrive at the
     server.  By itself, it cannot respond to any actual HTTP requests;
     it must be subclassed to handle each request method (e.g.  GET or
     POST). ‘BaseHTTPRequestHandler’ provides a number of class and
     instance variables, and methods for use by subclasses.

     The handler will parse the request and the headers, then call a
     method specific to the request type.  The method name is
     constructed from the request.  For example, for the request method
     ‘SPAM’, the ‘do_SPAM()’ method will be called with no arguments.
     All of the relevant information is stored in instance variables of
     the handler.  Subclasses should not need to override or extend the
     ‘__init__()’ method.

     ‘BaseHTTPRequestHandler’ has the following instance variables:

      -- Attribute: client_address

          Contains a tuple of the form ‘(host, port)’ referring to the
          client’s address.

      -- Attribute: server

          Contains the server instance.

      -- Attribute: close_connection

          Boolean that should be set before *note handle_one_request():
          3dc0. returns, indicating if another request may be expected,
          or if the connection should be shut down.

      -- Attribute: requestline

          Contains the string representation of the HTTP request line.
          The terminating CRLF is stripped.  This attribute should be
          set by *note handle_one_request(): 3dc0.  If no valid request
          line was processed, it should be set to the empty string.

      -- Attribute: command

          Contains the command (request type).  For example, ‘'GET'’.

      -- Attribute: path

          Contains the request path.  If query component of the URL is
          present, then ‘path’ includes the query.  Using the
          terminology of RFC 3986(2), ‘path’ here includes ‘hier-part’
          and the ‘query’.

      -- Attribute: request_version

          Contains the version string from the request.  For example,
          ‘'HTTP/1.0'’.

      -- Attribute: headers

          Holds an instance of the class specified by the *note
          MessageClass: 3dc5. class variable.  This instance parses and
          manages the headers in the HTTP request.  The *note
          parse_headers(): 1bd9. function from *note http.client: 6f. is
          used to parse the headers and it requires that the HTTP
          request provide a valid RFC 5322(3) style header.

      -- Attribute: rfile

          An *note io.BufferedIOBase: 697. input stream, ready to read
          from the start of the optional input data.

      -- Attribute: wfile

          Contains the output stream for writing a response back to the
          client.  Proper adherence to the HTTP protocol must be used
          when writing to this stream in order to achieve successful
          interoperation with HTTP clients.

          Changed in version 3.6: This is an *note io.BufferedIOBase:
          697. stream.

     ‘BaseHTTPRequestHandler’ has the following attributes:

      -- Attribute: server_version

          Specifies the server software version.  You may want to
          override this.  The format is multiple whitespace-separated
          strings, where each string is of the form name[/version].  For
          example, ‘'BaseHTTP/0.2'’.

      -- Attribute: sys_version

          Contains the Python system version, in a form usable by the
          *note version_string: 3dca. method and the *note
          server_version: 3dc8. class variable.  For example,
          ‘'Python/1.4'’.

      -- Attribute: error_message_format

          Specifies a format string that should be used by *note
          send_error(): f88. method for building an error response to
          the client.  The string is filled by default with variables
          from *note responses: 3c85. based on the status code that
          passed to ‘send_error()’.

      -- Attribute: error_content_type

          Specifies the Content-Type HTTP header of error responses sent
          to the client.  The default value is ‘'text/html'’.

      -- Attribute: protocol_version

          Specifies the HTTP version to which the server is conformant.
          It is sent in responses to let the client know the server’s
          communication capabilities for future requests.  If set to
          ‘'HTTP/1.1'’, the server will permit HTTP persistent
          connections; however, your server 'must' then include an
          accurate ‘Content-Length’ header (using *note send_header():
          3dcd.) in all of its responses to clients.  For backwards
          compatibility, the setting defaults to ‘'HTTP/1.0'’.

      -- Attribute: MessageClass

          Specifies an *note email.message.Message: 27c.-like class to
          parse HTTP headers.  Typically, this is not overridden, and it
          defaults to *note http.client.HTTPMessage: 3c9f.

      -- Attribute: responses

          This attribute contains a mapping of error code integers to
          two-element tuples containing a short and long message.  For
          example, ‘{code: (shortmessage, longmessage)}’.  The
          'shortmessage' is usually used as the 'message' key in an
          error response, and 'longmessage' as the 'explain' key.  It is
          used by *note send_response_only(): 3dce. and *note
          send_error(): f88. methods.

     A ‘BaseHTTPRequestHandler’ instance has the following methods:

      -- Method: handle ()

          Calls *note handle_one_request(): 3dc0. once (or, if
          persistent connections are enabled, multiple times) to handle
          incoming HTTP requests.  You should never need to override it;
          instead, implement appropriate ‘do_*()’ methods.

      -- Method: handle_one_request ()

          This method will parse and dispatch the request to the
          appropriate ‘do_*()’ method.  You should never need to
          override it.

      -- Method: handle_expect_100 ()

          When an HTTP/1.1 conformant server receives an ‘Expect:
          100-continue’ request header it responds back with a ‘100
          Continue’ followed by ‘200 OK’ headers.  This method can be
          overridden to raise an error if the server does not want the
          client to continue.  For e.g.  server can choose to send ‘417
          Expectation Failed’ as a response header and ‘return False’.

          Added in version 3.2.

      -- Method: send_error (code, message=None, explain=None)

          Sends and logs a complete error reply to the client.  The
          numeric 'code' specifies the HTTP error code, with 'message'
          as an optional, short, human readable description of the
          error.  The 'explain' argument can be used to provide more
          detailed information about the error; it will be formatted
          using the *note error_message_format: f89. attribute and
          emitted, after a complete set of headers, as the response
          body.  The *note responses: 3c85. attribute holds the default
          values for 'message' and 'explain' that will be used if no
          value is provided; for unknown codes the default value for
          both is the string ‘???’.  The body will be empty if the
          method is HEAD or the response code is one of the following:
          ‘1XX’, ‘204 No Content’, ‘205 Reset Content’, ‘304 Not
          Modified’.

          Changed in version 3.4: The error response includes a
          Content-Length header.  Added the 'explain' argument.

      -- Method: send_response (code, message=None)

          Adds a response header to the headers buffer and logs the
          accepted request.  The HTTP response line is written to the
          internal buffer, followed by 'Server' and 'Date' headers.  The
          values for these two headers are picked up from the *note
          version_string(): 3dca. and *note date_time_string(): 3dd2.
          methods, respectively.  If the server does not intend to send
          any other headers using the *note send_header(): 3dcd. method,
          then ‘send_response()’ should be followed by an *note
          end_headers(): 1110. call.

          Changed in version 3.3: Headers are stored to an internal
          buffer and *note end_headers(): 1110. needs to be called
          explicitly.

      -- Method: send_header (keyword, value)

          Adds the HTTP header to an internal buffer which will be
          written to the output stream when either *note end_headers():
          1110. or *note flush_headers(): 1111. is invoked.  'keyword'
          should specify the header keyword, with 'value' specifying its
          value.  Note that, after the send_header calls are done,
          ‘end_headers()’ MUST BE called in order to complete the
          operation.

          This method does not reject input containing CRLF sequences.

          Changed in version 3.2: Headers are stored in an internal
          buffer.

      -- Method: send_response_only (code, message=None)

          Sends the response header only, used for the purposes when
          ‘100 Continue’ response is sent by the server to the client.
          The headers not buffered and sent directly the output
          stream.If the 'message' is not specified, the HTTP message
          corresponding the response 'code' is sent.

          This method does not reject 'message' containing CRLF
          sequences.

          Added in version 3.2.

      -- Method: end_headers ()

          Adds a blank line (indicating the end of the HTTP headers in
          the response) to the headers buffer and calls *note
          flush_headers(): 1111.

          Changed in version 3.2: The buffered headers are written to
          the output stream.

      -- Method: flush_headers ()

          Finally send the headers to the output stream and flush the
          internal headers buffer.

          Added in version 3.3.

      -- Method: log_request (code='-', size='-')

          Logs an accepted (successful) request.  'code' should specify
          the numeric HTTP code associated with the response.  If a size
          of the response is available, then it should be passed as the
          'size' parameter.

      -- Method: log_error (...)

          Logs an error when a request cannot be fulfilled.  By default,
          it passes the message to *note log_message(): 3dd5, so it
          takes the same arguments ('format' and additional values).

      -- Method: log_message (format, ...)

          Logs an arbitrary message to ‘sys.stderr’.  This is typically
          overridden to create custom error logging mechanisms.  The
          'format' argument is a standard printf-style format string,
          where the additional arguments to ‘log_message()’ are applied
          as inputs to the formatting.  The client ip address and
          current date and time are prefixed to every message logged.

      -- Method: version_string ()

          Returns the server software’s version string.  This is a
          combination of the *note server_version: 3dc8. and *note
          sys_version: 3dc9. attributes.

      -- Method: date_time_string (timestamp=None)

          Returns the date and time given by 'timestamp' (which must be
          ‘None’ or in the format returned by *note time.time(): 254.),
          formatted for a message header.  If 'timestamp' is omitted, it
          uses the current date and time.

          The result looks like ‘'Sun, 06 Nov 1994 08:49:37 GMT'’.

      -- Method: log_date_time_string ()

          Returns the current date and time, formatted for logging.

      -- Method: address_string ()

          Returns the client address.

          Changed in version 3.3: Previously, a name lookup was
          performed.  To avoid name resolution delays, it now always
          returns the IP address.

 -- Class: http.server.SimpleHTTPRequestHandler (request,
          client_address, server, directory=None)

     This class serves files from the directory 'directory' and below,
     or the current directory if 'directory' is not provided, directly
     mapping the directory structure to HTTP requests.

     Changed in version 3.7: Added the 'directory' parameter.

     Changed in version 3.9: The 'directory' parameter accepts a *note
     path-like object: 2a0.

     A lot of the work, such as parsing the request, is done by the base
     class *note BaseHTTPRequestHandler: 110f.  This class implements
     the *note do_GET(): 3dd8. and *note do_HEAD(): 3dd9. functions.

     The following are defined as class-level attributes of
     ‘SimpleHTTPRequestHandler’:

      -- Attribute: server_version

          This will be ‘"SimpleHTTP/" + __version__’, where
          ‘__version__’ is defined at the module level.

      -- Attribute: extensions_map

          A dictionary mapping suffixes into MIME types, contains custom
          overrides for the default system mappings.  The mapping is
          used case-insensitively, and so should contain only
          lower-cased keys.

          Changed in version 3.9: This dictionary is no longer filled
          with the default system mappings, but only contains overrides.

     The ‘SimpleHTTPRequestHandler’ class defines the following methods:

      -- Method: do_HEAD ()

          This method serves the ‘'HEAD'’ request type: it sends the
          headers it would send for the equivalent ‘GET’ request.  See
          the *note do_GET(): 3dd8. method for a more complete
          explanation of the possible headers.

      -- Method: do_GET ()

          The request is mapped to a local file by interpreting the
          request as a path relative to the current working directory.

          If the request was mapped to a directory, the directory is
          checked for a file named ‘index.html’ or ‘index.htm’ (in that
          order).  If found, the file’s contents are returned; otherwise
          a directory listing is generated by calling the
          ‘list_directory()’ method.  This method uses *note
          os.listdir(): 113e. to scan the directory, and returns a ‘404’
          error response if the ‘listdir()’ fails.

          If the request was mapped to a file, it is opened.  Any *note
          OSError: 41a. exception in opening the requested file is
          mapped to a ‘404’, ‘'File not found'’ error.  If there was an
          ‘'If-Modified-Since'’ header in the request, and the file was
          not modified after this time, a ‘304’, ‘'Not Modified'’
          response is sent.  Otherwise, the content type is guessed by
          calling the ‘guess_type()’ method, which in turn uses the
          'extensions_map' variable, and the file contents are returned.

          A ‘'Content-type:'’ header with the guessed content type is
          output, followed by a ‘'Content-Length:'’ header with the
          file’s size and a ‘'Last-Modified:'’ header with the file’s
          modification time.

          Then follows a blank line signifying the end of the headers,
          and then the contents of the file are output.

          For example usage, see the implementation of the ‘test’
          function in Lib/http/server.py(4).

          Changed in version 3.7: Support of the ‘'If-Modified-Since'’
          header.

The *note SimpleHTTPRequestHandler: b5c. class can be used in the
following manner in order to create a very basic webserver serving files
relative to the current directory:

     import http.server
     import socketserver

     PORT = 8000

     Handler = http.server.SimpleHTTPRequestHandler

     with socketserver.TCPServer(("", PORT), Handler) as httpd:
         print("serving at port", PORT)
         httpd.serve_forever()

*note SimpleHTTPRequestHandler: b5c. can also be subclassed to enhance
behavior, such as using different index file names by overriding the
class attribute ‘index_pages’.

 -- Class: http.server.CGIHTTPRequestHandler (request, client_address,
          server)

     This class is used to serve either files or output of CGI scripts
     from the current directory and below.  Note that mapping HTTP
     hierarchic structure to local directory structure is exactly as in
     *note SimpleHTTPRequestHandler: b5c.

          Note: CGI scripts run by the ‘CGIHTTPRequestHandler’ class
          cannot execute redirects (HTTP code 302), because code 200
          (script output follows) is sent prior to execution of the CGI
          script.  This pre-empts the status code.

     The class will however, run the CGI script, instead of serving it
     as a file, if it guesses it to be a CGI script.  Only
     directory-based CGI are used — the other common server
     configuration is to treat special extensions as denoting CGI
     scripts.

     The ‘do_GET()’ and ‘do_HEAD()’ functions are modified to run CGI
     scripts and serve the output, instead of serving files, if the
     request leads to somewhere below the ‘cgi_directories’ path.

     The ‘CGIHTTPRequestHandler’ defines the following data member:

      -- Attribute: cgi_directories

          This defaults to ‘['/cgi-bin', '/htbin']’ and describes
          directories to treat as containing CGI scripts.

     The ‘CGIHTTPRequestHandler’ defines the following method:

      -- Method: do_POST ()

          This method serves the ‘'POST'’ request type, only allowed for
          CGI scripts.  Error 501, “Can only POST to CGI scripts”, is
          output when trying to POST to a non-CGI url.

     Note that CGI scripts will be run with UID of user nobody, for
     security reasons.  Problems with the CGI script will be translated
     to error 403.

     Deprecated since version 3.13, will be removed in version 3.15:
     ‘CGIHTTPRequestHandler’ is being removed in 3.15.  CGI has not been
     considered a good way to do things for well over a decade.  This
     code has been unmaintained for a while now and sees very little
     practical use.  Retaining it could lead to further *note security
     considerations: 3dbc.

* Menu:

* Command-line interface: Command-line interface<5>.
* Security considerations: Security considerations<3>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/http/server.py

   (2) https://datatracker.ietf.org/doc/html/rfc3986.html

   (3) https://datatracker.ietf.org/doc/html/rfc5322.html

   (4) https://github.com/python/cpython/tree/3.13/Lib/http/server.py


File: python.info,  Node: Command-line interface<5>,  Next: Security considerations<3>,  Up: http server — HTTP servers

5.22.17.1 Command-line interface
................................

‘http.server’ can also be invoked directly using the *note -m: 5e4.
switch of the interpreter.  The following example illustrates how to
serve files relative to the current directory:

     python -m http.server [OPTIONS] [port]

The following options are accepted:

 -- Option: port

     The server listens to port 8000 by default.  The default can be
     overridden by passing the desired port number as an argument:

          python -m http.server 9000

 -- Option: -b, --bind <address>

     Specifies a specific address to which it should bind.  Both IPv4
     and IPv6 addresses are supported.  By default, the server binds
     itself to all interfaces.  For example, the following command
     causes the server to bind to localhost only:

          python -m http.server --bind 127.0.0.1

     Added in version 3.4.

     Changed in version 3.8: Support IPv6 in the ‘--bind’ option.

 -- Option: -d, --directory <dir>

     Specifies a directory to which it should serve the files.  By
     default, the server uses the current directory.  For example, the
     following command uses a specific directory:

          python -m http.server --directory /tmp/

     Added in version 3.7.

 -- Option: -p, --protocol <version>

     Specifies the HTTP version to which the server is conformant.  By
     default, the server is conformant to HTTP/1.0.  For example, the
     following command runs an HTTP/1.1 conformant server:

          python -m http.server --protocol HTTP/1.1

     Added in version 3.11.

 -- Option: --cgi

     *note CGIHTTPRequestHandler: 2a1. can be enabled in the command
     line by passing the ‘--cgi’ option:

          python -m http.server --cgi

     Deprecated since version 3.13, will be removed in version 3.15:
     ‘http.server’ command line ‘--cgi’ support is being removed because
     *note CGIHTTPRequestHandler: 2a1. is being removed.

     Warning: *note CGIHTTPRequestHandler: 2a1. and the ‘--cgi’
     command-line option are not intended for use by untrusted clients
     and may be vulnerable to exploitation.  Always use within a secure
     environment.


File: python.info,  Node: Security considerations<3>,  Prev: Command-line interface<5>,  Up: http server — HTTP servers

5.22.17.2 Security considerations
.................................

*note SimpleHTTPRequestHandler: b5c. will follow symbolic links when
handling requests, this makes it possible for files outside of the
specified directory to be served.

Methods *note BaseHTTPRequestHandler.send_header(): 3dcd. and *note
BaseHTTPRequestHandler.send_response_only(): 3dce. assume sanitized
input and does not perform input validation such as checking for the
presence of CRLF sequences.  Untrusted input may result in HTTP Header
injection attacks.

Earlier versions of Python did not scrub control characters from the log
messages emitted to stderr from ‘python -m http.server’ or the default
*note BaseHTTPRequestHandler: 110f. ‘.log_message’ implementation.  This
could allow remote clients connecting to your server to send nefarious
control codes to your terminal.

Changed in version 3.12: Control characters are scrubbed in stderr logs.


File: python.info,  Node: http cookies — HTTP state management,  Next: http cookiejar — Cookie handling for HTTP clients,  Prev: http server — HTTP servers,  Up: Internet Protocols and Support

5.22.18 ‘http.cookies’ — HTTP state management
----------------------------------------------

'Source code:' Lib/http/cookies.py(1)

__________________________________________________________________

The ‘http.cookies’ module defines classes for abstracting the concept of
cookies, an HTTP state management mechanism.  It supports both simple
string-only cookies, and provides an abstraction for having any
serializable data-type as cookie value.

The module formerly strictly applied the parsing rules described in the
RFC 2109(2) and RFC 2068(3) specifications.  It has since been
discovered that MSIE 3.0x didn’t follow the character rules outlined in
those specs; many current-day browsers and servers have also relaxed
parsing rules when it comes to cookie handling.  As a result, this
module now uses parsing rules that are a bit less strict than they once
were.

The character set, *note string.ascii_letters: 130b, *note
string.digits: 247c. and ‘!#$%&'*+-.^_`|~:’ denote the set of valid
characters allowed by this module in a cookie name (as *note key: c21.).

Changed in version 3.3: Allowed ‘:’ as a valid cookie name character.

     Note: On encountering an invalid cookie, *note CookieError: 3deb.
     is raised, so if your cookie data comes from a browser you should
     always prepare for invalid data and catch ‘CookieError’ on parsing.

 -- Exception: http.cookies.CookieError

     Exception failing because of RFC 2109(4) invalidity: incorrect
     attributes, incorrect ‘Set-Cookie’ header, etc.

 -- Class: http.cookies.BaseCookie ([input])

     This class is a dictionary-like object whose keys are strings and
     whose values are *note Morsel: c24. instances.  Note that upon
     setting a key to a value, the value is first converted to a
     ‘Morsel’ containing the key and the value.

     If 'input' is given, it is passed to the *note load(): 3ded.
     method.

 -- Class: http.cookies.SimpleCookie ([input])

     This class derives from *note BaseCookie: 3dec. and overrides *note
     value_decode(): 3dee. and *note value_encode(): 3def.
     ‘SimpleCookie’ supports strings as cookie values.  When setting the
     value, ‘SimpleCookie’ calls the builtin *note str(): 44f. to
     convert the value to a string.  Values received from HTTP are kept
     as strings.

See also
........

Module *note http.cookiejar: 70.

     HTTP cookie handling for web 'clients'.  The *note http.cookiejar:
     70. and ‘http.cookies’ modules do not depend on each other.

RFC 2109(5) - HTTP State Management Mechanism

     This is the state management specification implemented by this
     module.

* Menu:

* Cookie Objects::
* Morsel Objects::
* Example: Example<12>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/http/cookies.py

   (2) https://datatracker.ietf.org/doc/html/rfc2109.html

   (3) https://datatracker.ietf.org/doc/html/rfc2068.html

   (4) https://datatracker.ietf.org/doc/html/rfc2109.html

   (5) https://datatracker.ietf.org/doc/html/rfc2109.html


File: python.info,  Node: Cookie Objects,  Next: Morsel Objects,  Up: http cookies — HTTP state management

5.22.18.1 Cookie Objects
........................

 -- Method: BaseCookie.value_decode (val)

     Return a tuple ‘(real_value, coded_value)’ from a string
     representation.  ‘real_value’ can be any type.  This method does no
     decoding in *note BaseCookie: 3dec. — it exists so it can be
     overridden.

 -- Method: BaseCookie.value_encode (val)

     Return a tuple ‘(real_value, coded_value)’.  'val' can be any type,
     but ‘coded_value’ will always be converted to a string.  This
     method does no encoding in *note BaseCookie: 3dec. — it exists so
     it can be overridden.

     In general, it should be the case that ‘value_encode()’ and *note
     value_decode(): 3dee. are inverses on the range of 'value_decode'.

 -- Method: BaseCookie.output (attrs=None, header='Set-Cookie:',
          sep='\r\n')

     Return a string representation suitable to be sent as HTTP headers.
     'attrs' and 'header' are sent to each *note Morsel: c24.’s *note
     output(): 3df3. method.  'sep' is used to join the headers
     together, and is by default the combination ‘'\r\n'’ (CRLF).

 -- Method: BaseCookie.js_output (attrs=None)

     Return an embeddable JavaScript snippet, which, if run on a browser
     which supports JavaScript, will act the same as if the HTTP headers
     was sent.

     The meaning for 'attrs' is the same as in *note output(): 3df2.

 -- Method: BaseCookie.load (rawdata)

     If 'rawdata' is a string, parse it as an ‘HTTP_COOKIE’ and add the
     values found there as *note Morsel: c24.s.  If it is a dictionary,
     it is equivalent to:

          for k, v in rawdata.items():
              cookie[k] = v


File: python.info,  Node: Morsel Objects,  Next: Example<12>,  Prev: Cookie Objects,  Up: http cookies — HTTP state management

5.22.18.2 Morsel Objects
........................

 -- Class: http.cookies.Morsel

     Abstract a key/value pair, which has some RFC 2109(1) attributes.

     Morsels are dictionary-like objects, whose set of keys is constant
     — the valid RFC 2109(2) attributes, which are:

           -- Attribute: expires
           -- Attribute: path
           -- Attribute: comment
           -- Attribute: domain

           -- Attribute: max-age
           -- Attribute: secure
           -- Attribute: version
           -- Attribute: httponly
           -- Attribute: samesite

     The attribute *note httponly: 141e. specifies that the cookie is
     only transferred in HTTP requests, and is not accessible through
     JavaScript.  This is intended to mitigate some forms of cross-site
     scripting.

     The attribute *note samesite: 3dfc. controls when the browser sends
     the cookie with cross-site requests.  This helps to mitigate CSRF
     attacks.  Valid values are “Strict” (only sent with same-site
     requests), “Lax” (sent with same-site requests and top-level
     navigations), and “None” (sent with same-site and cross-site
     requests).  When using “None”, the “secure” attribute must also be
     set, as required by modern browsers.

     The keys are case-insensitive and their default value is ‘''’.

     Changed in version 3.5: ‘__eq__()’ now takes *note key: c21. and
     *note value: c22. into account.

     Changed in version 3.7: Attributes *note key: c21, *note value:
     c22. and *note coded_value: c23. are read-only.  Use *note set():
     c25. for setting them.

     Changed in version 3.8: Added support for the *note samesite: 3dfc.
     attribute.

 -- Attribute: Morsel.value

     The value of the cookie.

 -- Attribute: Morsel.coded_value

     The encoded value of the cookie — this is what should be sent.

 -- Attribute: Morsel.key

     The name of the cookie.

 -- Method: Morsel.set (key, value, coded_value)

     Set the 'key', 'value' and 'coded_value' attributes.

 -- Method: Morsel.isReservedKey (K)

     Whether 'K' is a member of the set of keys of a *note Morsel: c24.

 -- Method: Morsel.output (attrs=None, header='Set-Cookie:')

     Return a string representation of the Morsel, suitable to be sent
     as an HTTP header.  By default, all the attributes are included,
     unless 'attrs' is given, in which case it should be a list of
     attributes to use.  'header' is by default ‘"Set-Cookie:"’.

 -- Method: Morsel.js_output (attrs=None)

     Return an embeddable JavaScript snippet, which, if run on a browser
     which supports JavaScript, will act the same as if the HTTP header
     was sent.

     The meaning for 'attrs' is the same as in *note output(): 3df3.

 -- Method: Morsel.OutputString (attrs=None)

     Return a string representing the Morsel, without any surrounding
     HTTP or JavaScript.

     The meaning for 'attrs' is the same as in *note output(): 3df3.

 -- Method: Morsel.update (values)

     Update the values in the Morsel dictionary with the values in the
     dictionary 'values'.  Raise an error if any of the keys in the
     'values' dict is not a valid RFC 2109(3) attribute.

     Changed in version 3.5: an error is raised for invalid keys.

 -- Method: Morsel.copy (value)

     Return a shallow copy of the Morsel object.

     Changed in version 3.5: return a Morsel object instead of a dict.

 -- Method: Morsel.setdefault (key, value=None)

     Raise an error if key is not a valid RFC 2109(4) attribute,
     otherwise behave the same as *note dict.setdefault(): 10b7.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2109.html

   (2) https://datatracker.ietf.org/doc/html/rfc2109.html

   (3) https://datatracker.ietf.org/doc/html/rfc2109.html

   (4) https://datatracker.ietf.org/doc/html/rfc2109.html


File: python.info,  Node: Example<12>,  Prev: Morsel Objects,  Up: http cookies — HTTP state management

5.22.18.3 Example
.................

The following example demonstrates how to use the ‘http.cookies’ module.

     >>> from http import cookies
     >>> C = cookies.SimpleCookie()
     >>> C["fig"] = "newton"
     >>> C["sugar"] = "wafer"
     >>> print(C) # generate HTTP headers
     Set-Cookie: fig=newton
     Set-Cookie: sugar=wafer
     >>> print(C.output()) # same thing
     Set-Cookie: fig=newton
     Set-Cookie: sugar=wafer
     >>> C = cookies.SimpleCookie()
     >>> C["rocky"] = "road"
     >>> C["rocky"]["path"] = "/cookie"
     >>> print(C.output(header="Cookie:"))
     Cookie: rocky=road; Path=/cookie
     >>> print(C.output(attrs=[], header="Cookie:"))
     Cookie: rocky=road
     >>> C = cookies.SimpleCookie()
     >>> C.load("chips=ahoy; vienna=finger") # load from a string (HTTP header)
     >>> print(C)
     Set-Cookie: chips=ahoy
     Set-Cookie: vienna=finger
     >>> C = cookies.SimpleCookie()
     >>> C.load('keebler="E=everybody; L=\\"Loves\\"; fudge=;";')
     >>> print(C)
     Set-Cookie: keebler="E=everybody; L=\"Loves\"; fudge=;"
     >>> C = cookies.SimpleCookie()
     >>> C["oreo"] = "doublestuff"
     >>> C["oreo"]["path"] = "/"
     >>> print(C)
     Set-Cookie: oreo=doublestuff; Path=/
     >>> C = cookies.SimpleCookie()
     >>> C["twix"] = "none for you"
     >>> C["twix"].value
     'none for you'
     >>> C = cookies.SimpleCookie()
     >>> C["number"] = 7 # equivalent to C["number"] = str(7)
     >>> C["string"] = "seven"
     >>> C["number"].value
     '7'
     >>> C["string"].value
     'seven'
     >>> print(C)
     Set-Cookie: number=7
     Set-Cookie: string=seven


File: python.info,  Node: http cookiejar — Cookie handling for HTTP clients,  Next: xmlrpc — XMLRPC server and client modules,  Prev: http cookies — HTTP state management,  Up: Internet Protocols and Support

5.22.19 ‘http.cookiejar’ — Cookie handling for HTTP clients
-----------------------------------------------------------

'Source code:' Lib/http/cookiejar.py(1)

__________________________________________________________________

The ‘http.cookiejar’ module defines classes for automatic handling of
HTTP cookies.  It is useful for accessing websites that require small
pieces of data – 'cookies' – to be set on the client machine by an HTTP
response from a web server, and then returned to the server in later
HTTP requests.

Both the regular Netscape cookie protocol and the protocol defined by
RFC 2965(2) are handled.  RFC 2965 handling is switched off by default.
RFC 2109(3) cookies are parsed as Netscape cookies and subsequently
treated either as Netscape or RFC 2965 cookies according to the ‘policy’
in effect.  Note that the great majority of cookies on the internet are
Netscape cookies.  ‘http.cookiejar’ attempts to follow the de-facto
Netscape cookie protocol (which differs substantially from that set out
in the original Netscape specification), including taking note of the
‘max-age’ and ‘port’ cookie-attributes introduced with RFC 2965.

     Note: The various named parameters found in ‘Set-Cookie’ and
     ‘Set-Cookie2’ headers (eg.  ‘domain’ and ‘expires’) are
     conventionally referred to as 'attributes'.  To distinguish them
     from Python attributes, the documentation for this module uses the
     term 'cookie-attribute' instead.

The module defines the following exception:

 -- Exception: http.cookiejar.LoadError

     Instances of *note FileCookieJar: 3e07. raise this exception on
     failure to load cookies from a file.  ‘LoadError’ is a subclass of
     *note OSError: 41a.

     Changed in version 3.3: ‘LoadError’ used to be a subtype of *note
     IOError: 1090, which is now an alias of *note OSError: 41a.

The following classes are provided:

 -- Class: http.cookiejar.CookieJar (policy=None)

     'policy' is an object implementing the *note CookiePolicy: 3e08.
     interface.

     The ‘CookieJar’ class stores HTTP cookies.  It extracts cookies
     from HTTP requests, and returns them in HTTP responses.
     ‘CookieJar’ instances automatically expire contained cookies when
     necessary.  Subclasses are also responsible for storing and
     retrieving cookies from a file or database.

 -- Class: http.cookiejar.FileCookieJar (filename=None, delayload=None,
          policy=None)

     'policy' is an object implementing the *note CookiePolicy: 3e08.
     interface.  For the other arguments, see the documentation for the
     corresponding attributes.

     A *note CookieJar: 3c23. which can load cookies from, and perhaps
     save cookies to, a file on disk.  Cookies are 'NOT' loaded from the
     named file until either the *note load(): 3e09. or *note revert():
     3e0a. method is called.  Subclasses of this class are documented in
     section *note FileCookieJar subclasses and co-operation with web
     browsers: 3e0b.

     This should not be initialized directly – use its subclasses below
     instead.

     Changed in version 3.8: The filename parameter supports a *note
     path-like object: 2a0.

 -- Class: http.cookiejar.CookiePolicy

     This class is responsible for deciding whether each cookie should
     be accepted from / returned to the server.

 -- Class: http.cookiejar.DefaultCookiePolicy (blocked_domains=None,
          allowed_domains=None, netscape=True, rfc2965=False,
          rfc2109_as_netscape=None, hide_cookie2=False,
          strict_domain=False, strict_rfc2965_unverifiable=True,
          strict_ns_unverifiable=False,
          strict_ns_domain=DefaultCookiePolicy.DomainLiberal,
          strict_ns_set_initial_dollar=False, strict_ns_set_path=False,
          secure_protocols=('https', 'wss'))

     Constructor arguments should be passed as keyword arguments only.
     'blocked_domains' is a sequence of domain names that we never
     accept cookies from, nor return cookies to.  'allowed_domains' if
     not *note None: 678, this is a sequence of the only domains for
     which we accept and return cookies.  'secure_protocols' is a
     sequence of protocols for which secure cookies can be added to.  By
     default 'https' and 'wss' (secure websocket) are considered secure
     protocols.  For all other arguments, see the documentation for
     *note CookiePolicy: 3e08. and ‘DefaultCookiePolicy’ objects.

     ‘DefaultCookiePolicy’ implements the standard accept / reject rules
     for Netscape and RFC 2965(4) cookies.  By default, RFC 2109(5)
     cookies (ie.  cookies received in a ‘Set-Cookie’ header with a
     version cookie-attribute of 1) are treated according to the RFC
     2965 rules.  However, if RFC 2965 handling is turned off or *note
     rfc2109_as_netscape: 3e0c. is ‘True’, RFC 2109 cookies are
     ‘downgraded’ by the *note CookieJar: 3c23. instance to Netscape
     cookies, by setting the ‘version’ attribute of the *note Cookie:
     3e0d. instance to 0.  ‘DefaultCookiePolicy’ also provides some
     parameters to allow some fine-tuning of policy.

 -- Class: http.cookiejar.Cookie

     This class represents Netscape, RFC 2109(6) and RFC 2965(7)
     cookies.  It is not expected that users of ‘http.cookiejar’
     construct their own ‘Cookie’ instances.  Instead, if necessary,
     call ‘make_cookies()’ on a *note CookieJar: 3c23. instance.

See also
........

Module *note urllib.request: 10b.

     URL opening with automatic cookie handling.

Module *note http.cookies: 71.

     HTTP cookie classes, principally useful for server-side code.  The
     ‘http.cookiejar’ and *note http.cookies: 71. modules do not depend
     on each other.

‘https://curl.se/rfc/cookie_spec.html’

     The specification of the original Netscape cookie protocol.  Though
     this is still the dominant protocol, the ‘Netscape cookie protocol’
     implemented by all the major browsers (and ‘http.cookiejar’) only
     bears a passing resemblance to the one sketched out in
     ‘cookie_spec.html’.

RFC 2109(8) - HTTP State Management Mechanism

     Obsoleted by RFC 2965(9).  Uses ‘Set-Cookie’ with version=1.

RFC 2965(10) - HTTP State Management Mechanism

     The Netscape protocol with the bugs fixed.  Uses ‘Set-Cookie2’ in
     place of ‘Set-Cookie’.  Not widely used.

‘https://kristol.org/cookie/errata.html’

     Unfinished errata to RFC 2965(11).

RFC 2964(12) - Use of HTTP State Management

* Menu:

* CookieJar and FileCookieJar Objects::
* FileCookieJar subclasses and co-operation with web browsers::
* CookiePolicy Objects::
* DefaultCookiePolicy Objects::
* Cookie Objects: Cookie Objects<2>.
* Examples: Examples<29>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/http/cookiejar.py

   (2) https://datatracker.ietf.org/doc/html/rfc2965.html

   (3) https://datatracker.ietf.org/doc/html/rfc2109.html

   (4) https://datatracker.ietf.org/doc/html/rfc2965.html

   (5) https://datatracker.ietf.org/doc/html/rfc2109.html

   (6) https://datatracker.ietf.org/doc/html/rfc2109.html

   (7) https://datatracker.ietf.org/doc/html/rfc2965.html

   (8) https://datatracker.ietf.org/doc/html/rfc2109.html

   (9) https://datatracker.ietf.org/doc/html/rfc2965.html

   (10) https://datatracker.ietf.org/doc/html/rfc2965.html

   (11) https://datatracker.ietf.org/doc/html/rfc2965.html

   (12) https://datatracker.ietf.org/doc/html/rfc2964.html


File: python.info,  Node: CookieJar and FileCookieJar Objects,  Next: FileCookieJar subclasses and co-operation with web browsers,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.1 CookieJar and FileCookieJar Objects
.............................................

*note CookieJar: 3c23. objects support the *note iterator: 1ac. protocol
for iterating over contained *note Cookie: 3e0d. objects.

*note CookieJar: 3c23. has the following methods:

 -- Method: CookieJar.add_cookie_header (request)

     Add correct ‘Cookie’ header to 'request'.

     If policy allows (ie.  the ‘rfc2965’ and ‘hide_cookie2’ attributes
     of the *note CookieJar: 3c23.’s *note CookiePolicy: 3e08. instance
     are true and false respectively), the ‘Cookie2’ header is also
     added when appropriate.

     The 'request' object (usually a *note urllib.request.Request: 1013.
     instance) must support the methods ‘get_full_url()’,
     ‘has_header()’, ‘get_header()’, ‘header_items()’,
     ‘add_unredirected_header()’ and the attributes ‘host’, ‘type’,
     ‘unverifiable’ and ‘origin_req_host’ as documented by *note
     urllib.request: 10b.

     Changed in version 3.3: 'request' object needs ‘origin_req_host’
     attribute.  Dependency on a deprecated method
     ‘get_origin_req_host()’ has been removed.

 -- Method: CookieJar.extract_cookies (response, request)

     Extract cookies from HTTP 'response' and store them in the *note
     CookieJar: 3c23, where allowed by policy.

     The *note CookieJar: 3c23. will look for allowable ‘Set-Cookie’ and
     ‘Set-Cookie2’ headers in the 'response' argument, and store cookies
     as appropriate (subject to the *note CookiePolicy.set_ok(): 3e12.
     method’s approval).

     The 'response' object (usually the result of a call to *note
     urllib.request.urlopen(): 293, or similar) should support an
     ‘info()’ method, which returns an *note email.message.Message: 27c.
     instance.

     The 'request' object (usually a *note urllib.request.Request: 1013.
     instance) must support the method ‘get_full_url()’ and the
     attributes ‘host’, ‘unverifiable’ and ‘origin_req_host’, as
     documented by *note urllib.request: 10b.  The request is used to
     set default values for cookie-attributes as well as for checking
     that the cookie is allowed to be set.

     Changed in version 3.3: 'request' object needs ‘origin_req_host’
     attribute.  Dependency on a deprecated method
     ‘get_origin_req_host()’ has been removed.

 -- Method: CookieJar.set_policy (policy)

     Set the *note CookiePolicy: 3e08. instance to be used.

 -- Method: CookieJar.make_cookies (response, request)

     Return sequence of *note Cookie: 3e0d. objects extracted from
     'response' object.

     See the documentation for *note extract_cookies(): 3e11. for the
     interfaces required of the 'response' and 'request' arguments.

 -- Method: CookieJar.set_cookie_if_ok (cookie, request)

     Set a *note Cookie: 3e0d. if policy says it’s OK to do so.

 -- Method: CookieJar.set_cookie (cookie)

     Set a *note Cookie: 3e0d, without checking with policy to see
     whether or not it should be set.

 -- Method: CookieJar.clear ([domain[, path[, name]]])

     Clear some cookies.

     If invoked without arguments, clear all cookies.  If given a single
     argument, only cookies belonging to that 'domain' will be removed.
     If given two arguments, cookies belonging to the specified 'domain'
     and URL 'path' are removed.  If given three arguments, then the
     cookie with the specified 'domain', 'path' and 'name' is removed.

     Raises *note KeyError: 345. if no matching cookie exists.

 -- Method: CookieJar.clear_session_cookies ()

     Discard all session cookies.

     Discards all contained cookies that have a true ‘discard’ attribute
     (usually because they had either no ‘max-age’ or ‘expires’
     cookie-attribute, or an explicit ‘discard’ cookie-attribute).  For
     interactive browsers, the end of a session usually corresponds to
     closing the browser window.

     Note that the ‘save()’ method won’t save session cookies anyway,
     unless you ask otherwise by passing a true 'ignore_discard'
     argument.

*note FileCookieJar: 3e07. implements the following additional methods:

 -- Method: FileCookieJar.save (filename=None, ignore_discard=False,
          ignore_expires=False)

     Save cookies to a file.

     This base class raises *note NotImplementedError: 228.  Subclasses
     may leave this method unimplemented.

     'filename' is the name of file in which to save cookies.  If
     'filename' is not specified, ‘self.filename’ is used (whose default
     is the value passed to the constructor, if any); if ‘self.filename’
     is *note None: 678, *note ValueError: 202. is raised.

     'ignore_discard': save even cookies set to be discarded.
     'ignore_expires': save even cookies that have expired

     The file is overwritten if it already exists, thus wiping all the
     cookies it contains.  Saved cookies can be restored later using the
     *note load(): 3e09. or *note revert(): 3e0a. methods.

 -- Method: FileCookieJar.load (filename=None, ignore_discard=False,
          ignore_expires=False)

     Load cookies from a file.

     Old cookies are kept unless overwritten by newly loaded ones.

     Arguments are as for *note save(): 3e19.

     The named file must be in the format understood by the class, or
     *note LoadError: 3e06. will be raised.  Also, *note OSError: 41a.
     may be raised, for example if the file does not exist.

     Changed in version 3.3: *note IOError: 1090. used to be raised, it
     is now an alias of *note OSError: 41a.

 -- Method: FileCookieJar.revert (filename=None, ignore_discard=False,
          ignore_expires=False)

     Clear all cookies and reload cookies from a saved file.

     ‘revert()’ can raise the same exceptions as *note load(): 3e09.  If
     there is a failure, the object’s state will not be altered.

*note FileCookieJar: 3e07. instances have the following public
attributes:

 -- Attribute: FileCookieJar.filename

     Filename of default file in which to keep cookies.  This attribute
     may be assigned to.

 -- Attribute: FileCookieJar.delayload

     If true, load cookies lazily from disk.  This attribute should not
     be assigned to.  This is only a hint, since this only affects
     performance, not behaviour (unless the cookies on disk are
     changing).  A *note CookieJar: 3c23. object may ignore it.  None of
     the *note FileCookieJar: 3e07. classes included in the standard
     library lazily loads cookies.


File: python.info,  Node: FileCookieJar subclasses and co-operation with web browsers,  Next: CookiePolicy Objects,  Prev: CookieJar and FileCookieJar Objects,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.2 FileCookieJar subclasses and co-operation with web browsers
.....................................................................

The following *note CookieJar: 3c23. subclasses are provided for reading
and writing.

 -- Class: http.cookiejar.MozillaCookieJar (filename=None,
          delayload=None, policy=None)

     A *note FileCookieJar: 3e07. that can load from and save cookies to
     disk in the Mozilla ‘cookies.txt’ file format (which is also used
     by curl and the Lynx and Netscape browsers).

          Note: This loses information about RFC 2965(1) cookies, and
          also about newer or non-standard cookie-attributes such as
          ‘port’.

          Warning: Back up your cookies before saving if you have
          cookies whose loss / corruption would be inconvenient (there
          are some subtleties which may lead to slight changes in the
          file over a load / save round-trip).

     Also note that cookies saved while Mozilla is running will get
     clobbered by Mozilla.

 -- Class: http.cookiejar.LWPCookieJar (filename=None, delayload=None,
          policy=None)

     A *note FileCookieJar: 3e07. that can load from and save cookies to
     disk in format compatible with the libwww-perl library’s
     ‘Set-Cookie3’ file format.  This is convenient if you want to store
     cookies in a human-readable file.

     Changed in version 3.8: The filename parameter supports a *note
     path-like object: 2a0.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: CookiePolicy Objects,  Next: DefaultCookiePolicy Objects,  Prev: FileCookieJar subclasses and co-operation with web browsers,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.3 CookiePolicy Objects
..............................

Objects implementing the *note CookiePolicy: 3e08. interface have the
following methods:

 -- Method: CookiePolicy.set_ok (cookie, request)

     Return boolean value indicating whether cookie should be accepted
     from server.

     'cookie' is a *note Cookie: 3e0d. instance.  'request' is an object
     implementing the interface defined by the documentation for *note
     CookieJar.extract_cookies(): 3e11.

 -- Method: CookiePolicy.return_ok (cookie, request)

     Return boolean value indicating whether cookie should be returned
     to server.

     'cookie' is a *note Cookie: 3e0d. instance.  'request' is an object
     implementing the interface defined by the documentation for *note
     CookieJar.add_cookie_header(): 3e10.

 -- Method: CookiePolicy.domain_return_ok (domain, request)

     Return ‘False’ if cookies should not be returned, given cookie
     domain.

     This method is an optimization.  It removes the need for checking
     every cookie with a particular domain (which might involve reading
     many files).  Returning true from ‘domain_return_ok()’ and *note
     path_return_ok(): 3e23. leaves all the work to *note return_ok():
     3e21.

     If ‘domain_return_ok()’ returns true for the cookie domain, *note
     path_return_ok(): 3e23. is called for the cookie path.  Otherwise,
     ‘path_return_ok()’ and *note return_ok(): 3e21. are never called
     for that cookie domain.  If ‘path_return_ok()’ returns true,
     ‘return_ok()’ is called with the *note Cookie: 3e0d. object itself
     for a full check.  Otherwise, ‘return_ok()’ is never called for
     that cookie path.

     Note that ‘domain_return_ok()’ is called for every 'cookie' domain,
     not just for the 'request' domain.  For example, the function might
     be called with both ‘".example.com"’ and ‘"www.example.com"’ if the
     request domain is ‘"www.example.com"’.  The same goes for *note
     path_return_ok(): 3e23.

     The 'request' argument is as documented for *note return_ok():
     3e21.

 -- Method: CookiePolicy.path_return_ok (path, request)

     Return ‘False’ if cookies should not be returned, given cookie
     path.

     See the documentation for *note domain_return_ok(): 3e22.

In addition to implementing the methods above, implementations of the
*note CookiePolicy: 3e08. interface must also supply the following
attributes, indicating which protocols should be used, and how.  All of
these attributes may be assigned to.

 -- Attribute: CookiePolicy.netscape

     Implement Netscape protocol.

 -- Attribute: CookiePolicy.rfc2965

     Implement RFC 2965(1) protocol.

 -- Attribute: CookiePolicy.hide_cookie2

     Don’t add ‘Cookie2’ header to requests (the presence of this header
     indicates to the server that we understand RFC 2965(2) cookies).

The most useful way to define a *note CookiePolicy: 3e08. class is by
subclassing from *note DefaultCookiePolicy: 1ba2. and overriding some or
all of the methods above.  ‘CookiePolicy’ itself may be used as a ‘null
policy’ to allow setting and receiving any and all cookies (this is
unlikely to be useful).

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2965.html

   (2) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: DefaultCookiePolicy Objects,  Next: Cookie Objects<2>,  Prev: CookiePolicy Objects,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.4 DefaultCookiePolicy Objects
.....................................

Implements the standard rules for accepting and returning cookies.

Both RFC 2965(1) and Netscape cookies are covered.  RFC 2965 handling is
switched off by default.

The easiest way to provide your own policy is to override this class and
call its methods in your overridden implementations before adding your
own additional checks:

     import http.cookiejar
     class MyCookiePolicy(http.cookiejar.DefaultCookiePolicy):
         def set_ok(self, cookie, request):
             if not http.cookiejar.DefaultCookiePolicy.set_ok(self, cookie, request):
                 return False
             if i_dont_want_to_store_this_cookie(cookie):
                 return False
             return True

In addition to the features required to implement the *note
CookiePolicy: 3e08. interface, this class allows you to block and allow
domains from setting and receiving cookies.  There are also some
strictness switches that allow you to tighten up the rather loose
Netscape protocol rules a little bit (at the cost of blocking some
benign cookies).

A domain blocklist and allowlist is provided (both off by default).
Only domains not in the blocklist and present in the allowlist (if the
allowlist is active) participate in cookie setting and returning.  Use
the 'blocked_domains' constructor argument, and ‘blocked_domains()’ and
‘set_blocked_domains()’ methods (and the corresponding argument and
methods for 'allowed_domains').  If you set an allowlist, you can turn
it off again by setting it to *note None: 678.

Domains in block or allow lists that do not start with a dot must equal
the cookie domain to be matched.  For example, ‘"example.com"’ matches a
blocklist entry of ‘"example.com"’, but ‘"www.example.com"’ does not.
Domains that do start with a dot are matched by more specific domains
too.  For example, both ‘"www.example.com"’ and
‘"www.coyote.example.com"’ match ‘".example.com"’ (but ‘"example.com"’
itself does not).  IP addresses are an exception, and must match
exactly.  For example, if blocked_domains contains ‘"192.168.1.2"’ and
‘".168.1.2"’, 192.168.1.2 is blocked, but 193.168.1.2 is not.

*note DefaultCookiePolicy: 1ba2. implements the following additional
methods:

 -- Method: DefaultCookiePolicy.blocked_domains ()

     Return the sequence of blocked domains (as a tuple).

 -- Method: DefaultCookiePolicy.set_blocked_domains (blocked_domains)

     Set the sequence of blocked domains.

 -- Method: DefaultCookiePolicy.is_blocked (domain)

     Return ‘True’ if 'domain' is on the blocklist for setting or
     receiving cookies.

 -- Method: DefaultCookiePolicy.allowed_domains ()

     Return *note None: 678, or the sequence of allowed domains (as a
     tuple).

 -- Method: DefaultCookiePolicy.set_allowed_domains (allowed_domains)

     Set the sequence of allowed domains, or *note None: 678.

 -- Method: DefaultCookiePolicy.is_not_allowed (domain)

     Return ‘True’ if 'domain' is not on the allowlist for setting or
     receiving cookies.

*note DefaultCookiePolicy: 1ba2. instances have the following
attributes, which are all initialised from the constructor arguments of
the same name, and which may all be assigned to.

 -- Attribute: DefaultCookiePolicy.rfc2109_as_netscape

     If true, request that the *note CookieJar: 3c23. instance downgrade
     RFC 2109(2) cookies (ie.  cookies received in a ‘Set-Cookie’ header
     with a version cookie-attribute of 1) to Netscape cookies by
     setting the version attribute of the *note Cookie: 3e0d. instance
     to 0.  The default value is *note None: 678, in which case RFC 2109
     cookies are downgraded if and only if RFC 2965(3) handling is
     turned off.  Therefore, RFC 2109 cookies are downgraded by default.

General strictness switches:

 -- Attribute: DefaultCookiePolicy.strict_domain

     Don’t allow sites to set two-component domains with country-code
     top-level domains like ‘.co.uk’, ‘.gov.uk’, ‘.co.nz’.etc.  This is
     far from perfect and isn’t guaranteed to work!

RFC 2965(4) protocol strictness switches:

 -- Attribute: DefaultCookiePolicy.strict_rfc2965_unverifiable

     Follow RFC 2965(5) rules on unverifiable transactions (usually, an
     unverifiable transaction is one resulting from a redirect or a
     request for an image hosted on another site).  If this is false,
     cookies are 'never' blocked on the basis of verifiability

Netscape protocol strictness switches:

 -- Attribute: DefaultCookiePolicy.strict_ns_unverifiable

     Apply RFC 2965(6) rules on unverifiable transactions even to
     Netscape cookies.

 -- Attribute: DefaultCookiePolicy.strict_ns_domain

     Flags indicating how strict to be with domain-matching rules for
     Netscape cookies.  See below for acceptable values.

 -- Attribute: DefaultCookiePolicy.strict_ns_set_initial_dollar

     Ignore cookies in Set-Cookie: headers that have names starting with
     ‘'$'’.

 -- Attribute: DefaultCookiePolicy.strict_ns_set_path

     Don’t allow setting cookies whose path doesn’t path-match request
     URI.

*note strict_ns_domain: 3e32. is a collection of flags.  Its value is
constructed by or-ing together (for example,
‘DomainStrictNoDots|DomainStrictNonDomain’ means both flags are set).

 -- Attribute: DefaultCookiePolicy.DomainStrictNoDots

     When setting cookies, the ‘host prefix’ must not contain a dot (eg.
     ‘www.foo.bar.com’ can’t set a cookie for ‘.bar.com’, because
     ‘www.foo’ contains a dot).

 -- Attribute: DefaultCookiePolicy.DomainStrictNonDomain

     Cookies that did not explicitly specify a ‘domain’ cookie-attribute
     can only be returned to a domain equal to the domain that set the
     cookie (eg.  ‘spam.example.com’ won’t be returned cookies from
     ‘example.com’ that had no ‘domain’ cookie-attribute).

 -- Attribute: DefaultCookiePolicy.DomainRFC2965Match

     When setting cookies, require a full RFC 2965(7) domain-match.

The following attributes are provided for convenience, and are the most
useful combinations of the above flags:

 -- Attribute: DefaultCookiePolicy.DomainLiberal

     Equivalent to 0 (ie.  all of the above Netscape domain strictness
     flags switched off).

 -- Attribute: DefaultCookiePolicy.DomainStrict

     Equivalent to ‘DomainStrictNoDots|DomainStrictNonDomain’.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2965.html

   (2) https://datatracker.ietf.org/doc/html/rfc2109.html

   (3) https://datatracker.ietf.org/doc/html/rfc2965.html

   (4) https://datatracker.ietf.org/doc/html/rfc2965.html

   (5) https://datatracker.ietf.org/doc/html/rfc2965.html

   (6) https://datatracker.ietf.org/doc/html/rfc2965.html

   (7) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: Cookie Objects<2>,  Next: Examples<29>,  Prev: DefaultCookiePolicy Objects,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.5 Cookie Objects
........................

*note Cookie: 3e0d. instances have Python attributes roughly
corresponding to the standard cookie-attributes specified in the various
cookie standards.  The correspondence is not one-to-one, because there
are complicated rules for assigning default values, because the
‘max-age’ and ‘expires’ cookie-attributes contain equivalent
information, and because RFC 2109(1) cookies may be ‘downgraded’ by
‘http.cookiejar’ from version 1 to version 0 (Netscape) cookies.

Assignment to these attributes should not be necessary other than in
rare circumstances in a *note CookiePolicy: 3e08. method.  The class
does not enforce internal consistency, so you should know what you’re
doing if you do that.

 -- Attribute: Cookie.version

     Integer or *note None: 678.  Netscape cookies have *note version:
     3e3b. 0.  RFC 2965(2) and RFC 2109(3) cookies have a ‘version’
     cookie-attribute of 1.  However, note that ‘http.cookiejar’ may
     ‘downgrade’ RFC 2109 cookies to Netscape cookies, in which case
     ‘version’ is 0.

 -- Attribute: Cookie.name

     Cookie name (a string).

 -- Attribute: Cookie.value

     Cookie value (a string), or *note None: 678.

 -- Attribute: Cookie.port

     String representing a port or a set of ports (eg.  ‘80’, or
     ‘80,8080’), or *note None: 678.

 -- Attribute: Cookie.domain

     Cookie domain (a string).

 -- Attribute: Cookie.path

     Cookie path (a string, eg.  ‘'/acme/rocket_launchers'’).

 -- Attribute: Cookie.secure

     ‘True’ if cookie should only be returned over a secure connection.

 -- Attribute: Cookie.expires

     Integer expiry date in seconds since epoch, or *note None: 678.
     See also the *note is_expired(): 3e43. method.

 -- Attribute: Cookie.discard

     ‘True’ if this is a session cookie.

 -- Attribute: Cookie.comment

     String comment from the server explaining the function of this
     cookie, or *note None: 678.

 -- Attribute: Cookie.comment_url

     URL linking to a comment from the server explaining the function of
     this cookie, or *note None: 678.

 -- Attribute: Cookie.rfc2109

     ‘True’ if this cookie was received as an RFC 2109(4) cookie (ie.
     the cookie arrived in a ‘Set-Cookie’ header, and the value of the
     Version cookie-attribute in that header was 1).  This attribute is
     provided because ‘http.cookiejar’ may ‘downgrade’ RFC 2109 cookies
     to Netscape cookies, in which case *note version: 3e3b. is 0.

 -- Attribute: Cookie.port_specified

     ‘True’ if a port or set of ports was explicitly specified by the
     server (in the ‘Set-Cookie’ / ‘Set-Cookie2’ header).

 -- Attribute: Cookie.domain_specified

     ‘True’ if a domain was explicitly specified by the server.

 -- Attribute: Cookie.domain_initial_dot

     ‘True’ if the domain explicitly specified by the server began with
     a dot (‘'.'’).

Cookies may have additional non-standard cookie-attributes.  These may
be accessed using the following methods:

 -- Method: Cookie.has_nonstandard_attr (name)

     Return ‘True’ if cookie has the named cookie-attribute.

 -- Method: Cookie.get_nonstandard_attr (name, default=None)

     If cookie has the named cookie-attribute, return its value.
     Otherwise, return 'default'.

 -- Method: Cookie.set_nonstandard_attr (name, value)

     Set the value of the named cookie-attribute.

The *note Cookie: 3e0d. class also defines the following method:

 -- Method: Cookie.is_expired (now=None)

     ‘True’ if cookie has passed the time at which the server requested
     it should expire.  If 'now' is given (in seconds since the epoch),
     return whether the cookie has expired at the specified time.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2109.html

   (2) https://datatracker.ietf.org/doc/html/rfc2965.html

   (3) https://datatracker.ietf.org/doc/html/rfc2109.html

   (4) https://datatracker.ietf.org/doc/html/rfc2109.html


File: python.info,  Node: Examples<29>,  Prev: Cookie Objects<2>,  Up: http cookiejar — Cookie handling for HTTP clients

5.22.19.6 Examples
..................

The first example shows the most common usage of ‘http.cookiejar’:

     import http.cookiejar, urllib.request
     cj = http.cookiejar.CookieJar()
     opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
     r = opener.open("http://example.com/")

This example illustrates how to open a URL using your Netscape, Mozilla,
or Lynx cookies (assumes Unix/Netscape convention for location of the
cookies file):

     import os, http.cookiejar, urllib.request
     cj = http.cookiejar.MozillaCookieJar()
     cj.load(os.path.join(os.path.expanduser("~"), ".netscape", "cookies.txt"))
     opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
     r = opener.open("http://example.com/")

The next example illustrates the use of *note DefaultCookiePolicy: 1ba2.
Turn on RFC 2965(1) cookies, be more strict about domains when setting
and returning Netscape cookies, and block some domains from setting
cookies or having them returned:

     import urllib.request
     from http.cookiejar import CookieJar, DefaultCookiePolicy
     policy = DefaultCookiePolicy(
         rfc2965=True, strict_ns_domain=Policy.DomainStrict,
         blocked_domains=["ads.net", ".ads.net"])
     cj = CookieJar(policy)
     opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
     r = opener.open("http://example.com/")

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2965.html


File: python.info,  Node: xmlrpc — XMLRPC server and client modules,  Next: xmlrpc client — XML-RPC client access,  Prev: http cookiejar — Cookie handling for HTTP clients,  Up: Internet Protocols and Support

5.22.20 ‘xmlrpc’ — XMLRPC server and client modules
---------------------------------------------------

XML-RPC is a Remote Procedure Call method that uses XML passed via HTTP
as a transport.  With it, a client can call methods with parameters on a
remote server (the server is named by a URI) and get back structured
data.

‘xmlrpc’ is a package that collects server and client modules
implementing XML-RPC. The modules are:

   * *note xmlrpc.client: 12e.

   * *note xmlrpc.server: 12f.


File: python.info,  Node: xmlrpc client — XML-RPC client access,  Next: xmlrpc server — Basic XML-RPC servers,  Prev: xmlrpc — XMLRPC server and client modules,  Up: Internet Protocols and Support

5.22.21 ‘xmlrpc.client’ — XML-RPC client access
-----------------------------------------------

'Source code:' Lib/xmlrpc/client.py(1)

__________________________________________________________________

XML-RPC is a Remote Procedure Call method that uses XML passed via
HTTP(S) as a transport.  With it, a client can call methods with
parameters on a remote server (the server is named by a URI) and get
back structured data.  This module supports writing XML-RPC client code;
it handles all the details of translating between conformable Python
objects and XML on the wire.

     Warning: The ‘xmlrpc.client’ module is not secure against
     maliciously constructed data.  If you need to parse untrusted or
     unauthenticated data, see *note XML security: 39b7.

Changed in version 3.5: For HTTPS URIs, ‘xmlrpc.client’ now performs all
the necessary certificate and hostname checks by default.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

 -- Class: xmlrpc.client.ServerProxy (uri, transport=None,
          encoding=None, verbose=False, allow_none=False,
          use_datetime=False, use_builtin_types=False, *, headers=(),
          context=None)

     A ‘ServerProxy’ instance is an object that manages communication
     with a remote XML-RPC server.  The required first argument is a URI
     (Uniform Resource Indicator), and will normally be the URL of the
     server.  The optional second argument is a transport factory
     instance; by default it is an internal ‘SafeTransport’ instance for
     https: URLs and an internal HTTP ‘Transport’ instance otherwise.
     The optional third argument is an encoding, by default UTF-8.  The
     optional fourth argument is a debugging flag.

     The following parameters govern the use of the returned proxy
     instance.  If 'allow_none' is true, the Python constant ‘None’ will
     be translated into XML; the default behaviour is for ‘None’ to
     raise a *note TypeError: 2c3.  This is a commonly used extension to
     the XML-RPC specification, but isn’t supported by all clients and
     servers; see http://ontosys.com/xml-rpc/extensions.php(2) for a
     description.  The 'use_builtin_types' flag can be used to cause
     date/time values to be presented as *note datetime.datetime: 1cc.
     objects and binary data to be presented as *note bytes: 1c2.
     objects; this flag is false by default.  ‘datetime.datetime’,
     ‘bytes’ and *note bytearray: 2ea. objects may be passed to calls.
     The 'headers' parameter is an optional sequence of HTTP headers to
     send with each request, expressed as a sequence of 2-tuples
     representing the header name and value.  (e.g.  ‘[('Header-Name',
     'value')]’).  If an HTTPS URL is provided, 'context' may be *note
     ssl.SSLContext: 294. and configures the SSL settings of the
     underlying HTTPS connection.  The obsolete 'use_datetime' flag is
     similar to 'use_builtin_types' but it applies only to date/time
     values.

     Changed in version 3.3: The 'use_builtin_types' flag was added.

     Changed in version 3.8: The 'headers' parameter was added.

     Both the HTTP and HTTPS transports support the URL syntax extension
     for HTTP Basic Authentication: ‘http://user:pass@host:port/path’.
     The ‘user:pass’ portion will be base64-encoded as an HTTP
     ‘Authorization’ header, and sent to the remote server as part of
     the connection process when invoking an XML-RPC method.  You only
     need to use this if the remote server requires a Basic
     Authentication user and password.

     The returned instance is a proxy object with methods that can be
     used to invoke corresponding RPC calls on the remote server.  If
     the remote server supports the introspection API, the proxy can
     also be used to query the remote server for the methods it supports
     (service discovery) and fetch other server-associated metadata.

     Types that are conformable (e.g.  that can be marshalled through
     XML), include the following (and except where noted, they are
     unmarshalled as the same Python type):

     XML-RPC type               Python type
                                
     ---------------------------------------------------------------------------------------
                                
     ‘boolean’                  *note bool: 46b.
                                
                                
     ‘int’, ‘i1’, ‘i2’, ‘i4’,   *note int: 257. in range from -2147483648 to 2147483647.
     ‘i8’ or ‘biginteger’       Values get the ‘<int>’ tag.
                                
                                
     ‘double’ or ‘float’        *note float: 2f7.  Values get the ‘<double>’ tag.
                                
                                
     ‘string’                   *note str: 44f.
                                
                                
     ‘array’                    *note list: 614. or *note tuple: 373. containing
                                conformable elements.  Arrays are returned as ‘lists’.
                                
                                
     ‘struct’                   *note dict: 256.  Keys must be strings, values may be any
                                conformable type.  Objects of user-defined classes can be
                                passed in; only their *note __dict__: 55e. attribute is
                                transmitted.
                                
                                
     ‘dateTime.iso8601’         *note DateTime: 1431. or *note datetime.datetime: 1cc.
                                Returned type depends on values of 'use_builtin_types'
                                and 'use_datetime' flags.
                                
                                
     ‘base64’                   *note Binary: 3e55, *note bytes: 1c2. or
                                *note bytearray: 2ea.  Returned type depends on the value
                                of the 'use_builtin_types' flag.
                                
                                
     ‘nil’                      The ‘None’ constant.  Passing is allowed only if
                                'allow_none' is true.
                                
                                
     ‘bigdecimal’               *note decimal.Decimal: 29d.  Returned type only.
                                

     This is the full set of data types supported by XML-RPC. Method
     calls may also raise a special *note Fault: 3e56. instance, used to
     signal XML-RPC server errors, or *note ProtocolError: 3e57. used to
     signal an error in the HTTP/HTTPS transport layer.  Both ‘Fault’
     and ‘ProtocolError’ derive from a base class called ‘Error’.  Note
     that the xmlrpc client module currently does not marshal instances
     of subclasses of built-in types.

     When passing strings, characters special to XML such as ‘<’, ‘>’,
     and ‘&’ will be automatically escaped.  However, it’s the caller’s
     responsibility to ensure that the string is free of characters that
     aren’t allowed in XML, such as the control characters with ASCII
     values between 0 and 31 (except, of course, tab, newline and
     carriage return); failing to do this will result in an XML-RPC
     request that isn’t well-formed XML. If you have to pass arbitrary
     bytes via XML-RPC, use *note bytes: 1c2. or *note bytearray: 2ea.
     classes or the *note Binary: 3e55. wrapper class described below.

     ‘Server’ is retained as an alias for ‘ServerProxy’ for backwards
     compatibility.  New code should use ‘ServerProxy’.

     Changed in version 3.5: Added the 'context' argument.

     Changed in version 3.6: Added support of type tags with prefixes
     (e.g.  ‘ex:nil’).  Added support of unmarshalling additional types
     used by Apache XML-RPC implementation for numerics: ‘i1’, ‘i2’,
     ‘i8’, ‘biginteger’, ‘float’ and ‘bigdecimal’.  See
     ‘https://ws.apache.org/xmlrpc/types.html’ for a description.

See also
........

XML-RPC HOWTO(3)

     A good description of XML-RPC operation and client software in
     several languages.  Contains pretty much everything an XML-RPC
     client developer needs to know.

XML-RPC Introspection(4)

     Describes the XML-RPC protocol extension for introspection.

XML-RPC Specification(5)

     The official specification.

* Menu:

* ServerProxy Objects::
* DateTime Objects::
* Binary Objects::
* Fault Objects::
* ProtocolError Objects::
* MultiCall Objects::
* Convenience Functions::
* Example of Client Usage::
* Example of Client and Server Usage::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/xmlrpc/client.py

   (2) 
https://web.archive.org/web/20130120074804/http://ontosys.com/xml-rpc/extensions.php

   (3) https://tldp.org/HOWTO/XML-RPC-HOWTO/index.html

   (4) https://xmlrpc-c.sourceforge.io/introspection.html

   (5) http://xmlrpc.scripting.com/spec.html


File: python.info,  Node: ServerProxy Objects,  Next: DateTime Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.1 ServerProxy Objects
.............................

A *note ServerProxy: a65. instance has a method corresponding to each
remote procedure call accepted by the XML-RPC server.  Calling the
method performs an RPC, dispatched by both name and argument signature
(e.g.  the same method name can be overloaded with multiple argument
signatures).  The RPC finishes by returning a value, which may be either
returned data in a conformant type or a *note Fault: 3e56. or *note
ProtocolError: 3e57. object indicating an error.

Servers that support the XML introspection API support some common
methods grouped under the reserved ‘system’ attribute:

 -- Method: ServerProxy.system.listMethods ()

     This method returns a list of strings, one for each (non-system)
     method supported by the XML-RPC server.

 -- Method: ServerProxy.system.methodSignature (name)

     This method takes one parameter, the name of a method implemented
     by the XML-RPC server.  It returns an array of possible signatures
     for this method.  A signature is an array of types.  The first of
     these types is the return type of the method, the rest are
     parameters.

     Because multiple signatures (ie.  overloading) is permitted, this
     method returns a list of signatures rather than a singleton.

     Signatures themselves are restricted to the top level parameters
     expected by a method.  For instance if a method expects one array
     of structs as a parameter, and it returns a string, its signature
     is simply “string, array”.  If it expects three integers and
     returns a string, its signature is “string, int, int, int”.

     If no signature is defined for the method, a non-array value is
     returned.  In Python this means that the type of the returned value
     will be something other than list.

 -- Method: ServerProxy.system.methodHelp (name)

     This method takes one parameter, the name of a method implemented
     by the XML-RPC server.  It returns a documentation string
     describing the use of that method.  If no such string is available,
     an empty string is returned.  The documentation string may contain
     HTML markup.

Changed in version 3.5: Instances of *note ServerProxy: a65. support the
*note context manager: 5d7. protocol for closing the underlying
transport.

A working example follows.  The server code:

     from xmlrpc.server import SimpleXMLRPCServer

     def is_even(n):
         return n % 2 == 0

     server = SimpleXMLRPCServer(("localhost", 8000))
     print("Listening on port 8000...")
     server.register_function(is_even, "is_even")
     server.serve_forever()

The client code for the preceding server:

     import xmlrpc.client

     with xmlrpc.client.ServerProxy("http://localhost:8000/") as proxy:
         print("3 is even: %s" % str(proxy.is_even(3)))
         print("100 is even: %s" % str(proxy.is_even(100)))


File: python.info,  Node: DateTime Objects,  Next: Binary Objects,  Prev: ServerProxy Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.2 DateTime Objects
..........................

 -- Class: xmlrpc.client.DateTime

     This class may be initialized with seconds since the epoch, a time
     tuple, an ISO 8601 time/date string, or a *note datetime.datetime:
     1cc. instance.  It has the following methods, supported mainly for
     internal use by the marshalling/unmarshalling code:

      -- Method: decode (string)

          Accept a string as the instance’s new time value.

      -- Method: encode (out)

          Write the XML-RPC encoding of this ‘DateTime’ item to the
          'out' stream object.

     It also supports certain of Python’s built-in operators through
     *note rich comparison: 12e7. and *note __repr__(): 61f. methods.

A working example follows.  The server code:

     import datetime as dt
     from xmlrpc.server import SimpleXMLRPCServer
     import xmlrpc.client

     def today():
         today = dt.datetime.today()
         return xmlrpc.client.DateTime(today)

     server = SimpleXMLRPCServer(("localhost", 8000))
     print("Listening on port 8000...")
     server.register_function(today, "today")
     server.serve_forever()

The client code for the preceding server:

     import xmlrpc.client
     import datetime as dt

     proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")

     today = proxy.today()
     # convert the ISO 8601 string to a datetime object
     converted = dt.datetime.strptime(today.value, "%Y%m%dT%H:%M:%S")
     print(f"Today: {converted.strftime('%d.%m.%Y, %H:%M')}")


File: python.info,  Node: Binary Objects,  Next: Fault Objects,  Prev: DateTime Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.3 Binary Objects
........................

 -- Class: xmlrpc.client.Binary

     This class may be initialized from bytes data (which may include
     NULs).  The primary access to the content of a ‘Binary’ object is
     provided by an attribute:

      -- Attribute: data

          The binary data encapsulated by the ‘Binary’ instance.  The
          data is provided as a *note bytes: 1c2. object.

     ‘Binary’ objects have the following methods, supported mainly for
     internal use by the marshalling/unmarshalling code:

      -- Method: decode (bytes)

          Accept a base64 *note bytes: 1c2. object and decode it as the
          instance’s new data.

      -- Method: encode (out)

          Write the XML-RPC base 64 encoding of this binary item to the
          'out' stream object.

          The encoded data will have newlines every 76 characters as per
          RFC 2045 section 6.8(1), which was the de facto standard
          base64 specification when the XML-RPC spec was written.

     It also supports certain of Python’s built-in operators through
     *note __eq__(): b13. and *note __ne__(): 1567. methods.

Example usage of the binary objects.  We’re going to transfer an image
over XMLRPC:

     from xmlrpc.server import SimpleXMLRPCServer
     import xmlrpc.client

     def python_logo():
         with open("python_logo.jpg", "rb") as handle:
             return xmlrpc.client.Binary(handle.read())

     server = SimpleXMLRPCServer(("localhost", 8000))
     print("Listening on port 8000...")
     server.register_function(python_logo, 'python_logo')

     server.serve_forever()

The client gets the image and saves it to a file:

     import xmlrpc.client

     proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
     with open("fetched_python_logo.jpg", "wb") as handle:
         handle.write(proxy.python_logo().data)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2045.html#section-6.8


File: python.info,  Node: Fault Objects,  Next: ProtocolError Objects,  Prev: Binary Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.4 Fault Objects
.......................

 -- Class: xmlrpc.client.Fault

     A ‘Fault’ object encapsulates the content of an XML-RPC fault tag.
     Fault objects have the following attributes:

      -- Attribute: faultCode

          An int indicating the fault type.

      -- Attribute: faultString

          A string containing a diagnostic message associated with the
          fault.

In the following example we’re going to intentionally cause a *note
Fault: 3e56. by returning a complex type object.  The server code:

     from xmlrpc.server import SimpleXMLRPCServer

     # A marshalling error is going to occur because we're returning a
     # complex number
     def add(x, y):
         return x+y+0j

     server = SimpleXMLRPCServer(("localhost", 8000))
     print("Listening on port 8000...")
     server.register_function(add, 'add')

     server.serve_forever()

The client code for the preceding server:

     import xmlrpc.client

     proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
     try:
         proxy.add(2, 5)
     except xmlrpc.client.Fault as err:
         print("A fault occurred")
         print("Fault code: %d" % err.faultCode)
         print("Fault string: %s" % err.faultString)


File: python.info,  Node: ProtocolError Objects,  Next: MultiCall Objects,  Prev: Fault Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.5 ProtocolError Objects
...............................

 -- Class: xmlrpc.client.ProtocolError

     A ‘ProtocolError’ object describes a protocol error in the
     underlying transport layer (such as a 404 ‘not found’ error if the
     server named by the URI does not exist).  It has the following
     attributes:

      -- Attribute: url

          The URI or URL that triggered the error.

      -- Attribute: errcode

          The error code.

      -- Attribute: errmsg

          The error message or diagnostic string.

      -- Attribute: headers

          A dict containing the headers of the HTTP/HTTPS request that
          triggered the error.

In the following example we’re going to intentionally cause a *note
ProtocolError: 3e57. by providing an invalid URI:

     import xmlrpc.client

     # create a ServerProxy with a URI that doesn't respond to XMLRPC requests
     proxy = xmlrpc.client.ServerProxy("http://google.com/")

     try:
         proxy.some_method()
     except xmlrpc.client.ProtocolError as err:
         print("A protocol error occurred")
         print("URL: %s" % err.url)
         print("HTTP/HTTPS headers: %s" % err.headers)
         print("Error code: %d" % err.errcode)
         print("Error message: %s" % err.errmsg)


File: python.info,  Node: MultiCall Objects,  Next: Convenience Functions,  Prev: ProtocolError Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.6 MultiCall Objects
...........................

The *note MultiCall: 3e71. object provides a way to encapsulate multiple
calls to a remote server into a single request (1).

 -- Class: xmlrpc.client.MultiCall (server)

     Create an object used to boxcar method calls.  'server' is the
     eventual target of the call.  Calls can be made to the result
     object, but they will immediately return ‘None’, and only store the
     call name and parameters in the ‘MultiCall’ object.  Calling the
     object itself causes all stored calls to be transmitted as a single
     ‘system.multicall’ request.  The result of this call is a *note
     generator: 109f.; iterating over this generator yields the
     individual results.

A usage example of this class follows.  The server code:

     from xmlrpc.server import SimpleXMLRPCServer

     def add(x, y):
         return x + y

     def subtract(x, y):
         return x - y

     def multiply(x, y):
         return x * y

     def divide(x, y):
         return x // y

     # A simple server with simple arithmetic functions
     server = SimpleXMLRPCServer(("localhost", 8000))
     print("Listening on port 8000...")
     server.register_multicall_functions()
     server.register_function(add, 'add')
     server.register_function(subtract, 'subtract')
     server.register_function(multiply, 'multiply')
     server.register_function(divide, 'divide')
     server.serve_forever()

The client code for the preceding server:

     import xmlrpc.client

     proxy = xmlrpc.client.ServerProxy("http://localhost:8000/")
     multicall = xmlrpc.client.MultiCall(proxy)
     multicall.add(7, 3)
     multicall.subtract(7, 3)
     multicall.multiply(7, 3)
     multicall.divide(7, 3)
     result = multicall()

     print("7+3=%d, 7-3=%d, 7*3=%d, 7//3=%d" % tuple(result))

   ---------- Footnotes ----------

   (1) This approach has been first presented in a discussion on
xmlrpc.com
(https://web.archive.org/web/20060624230303/http://www.xmlrpc.com/discuss/msgReader$1208?mode=topic).


File: python.info,  Node: Convenience Functions,  Next: Example of Client Usage,  Prev: MultiCall Objects,  Up: xmlrpc client — XML-RPC client access

5.22.21.7 Convenience Functions
...............................

 -- Function: xmlrpc.client.dumps (params, methodname=None,
          methodresponse=None, encoding=None, allow_none=False)

     Convert 'params' into an XML-RPC request, or into a response if
     'methodresponse' is true.  'params' can be either a tuple of
     arguments or an instance of the *note Fault: 3e56. exception class.
     If 'methodresponse' is true, only a single value can be returned,
     meaning that 'params' must be of length 1.  'encoding', if
     supplied, is the encoding to use in the generated XML; the default
     is UTF-8.  Python’s *note None: 678. value cannot be used in
     standard XML-RPC; to allow using it via an extension, provide a
     true value for 'allow_none'.

 -- Function: xmlrpc.client.loads (data, use_datetime=False,
          use_builtin_types=False)

     Convert an XML-RPC request or response into Python objects, a
     ‘(params, methodname)’.  'params' is a tuple of argument;
     'methodname' is a string, or ‘None’ if no method name is present in
     the packet.  If the XML-RPC packet represents a fault condition,
     this function will raise a *note Fault: 3e56. exception.  The
     'use_builtin_types' flag can be used to cause date/time values to
     be presented as *note datetime.datetime: 1cc. objects and binary
     data to be presented as *note bytes: 1c2. objects; this flag is
     false by default.

     The obsolete 'use_datetime' flag is similar to 'use_builtin_types'
     but it applies only to date/time values.

     Changed in version 3.3: The 'use_builtin_types' flag was added.


File: python.info,  Node: Example of Client Usage,  Next: Example of Client and Server Usage,  Prev: Convenience Functions,  Up: xmlrpc client — XML-RPC client access

5.22.21.8 Example of Client Usage
.................................

     # simple test program (from the XML-RPC specification)
     from xmlrpc.client import ServerProxy, Error

     # server = ServerProxy("http://localhost:8000") # local server
     with ServerProxy("http://betty.userland.com") as proxy:

         print(proxy)

         try:
             print(proxy.examples.getStateName(41))
         except Error as v:
             print("ERROR", v)

To access an XML-RPC server through a HTTP proxy, you need to define a
custom transport.  The following example shows how:

     import http.client
     import xmlrpc.client

     class ProxiedTransport(xmlrpc.client.Transport):

         def set_proxy(self, host, port=None, headers=None):
             self.proxy = host, port
             self.proxy_headers = headers

         def make_connection(self, host):
             connection = http.client.HTTPConnection(*self.proxy)
             connection.set_tunnel(host, headers=self.proxy_headers)
             self._connection = host, connection
             return connection

     transport = ProxiedTransport()
     transport.set_proxy('proxy-server', 8080)
     server = xmlrpc.client.ServerProxy('http://betty.userland.com', transport=transport)
     print(server.examples.getStateName(41))


File: python.info,  Node: Example of Client and Server Usage,  Prev: Example of Client Usage,  Up: xmlrpc client — XML-RPC client access

5.22.21.9 Example of Client and Server Usage
............................................

See *note SimpleXMLRPCServer example: 3e77.


File: python.info,  Node: xmlrpc server — Basic XML-RPC servers,  Next: ipaddress — IPv4/IPv6 manipulation library,  Prev: xmlrpc client — XML-RPC client access,  Up: Internet Protocols and Support

5.22.22 ‘xmlrpc.server’ — Basic XML-RPC servers
-----------------------------------------------

'Source code:' Lib/xmlrpc/server.py(1)

__________________________________________________________________

The ‘xmlrpc.server’ module provides a basic server framework for XML-RPC
servers written in Python.  Servers can either be free standing, using
*note SimpleXMLRPCServer: 3e7b, or embedded in a CGI environment, using
*note CGIXMLRPCRequestHandler: 3e7c.

     Warning: The ‘xmlrpc.server’ module is not secure against
     maliciously constructed data.  If you need to parse untrusted or
     unauthenticated data, see *note XML security: 39b7.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

 -- Class: xmlrpc.server.SimpleXMLRPCServer (addr,
          requestHandler=SimpleXMLRPCRequestHandler, logRequests=True,
          allow_none=False, encoding=None, bind_and_activate=True,
          use_builtin_types=False)

     Create a new server instance.  This class provides methods for
     registration of functions that can be called by the XML-RPC
     protocol.  The 'requestHandler' parameter should be a factory for
     request handler instances; it defaults to *note
     SimpleXMLRPCRequestHandler: 1371.  The 'addr' and 'requestHandler'
     parameters are passed to the *note socketserver.TCPServer: 1369.
     constructor.  If 'logRequests' is true (the default), requests will
     be logged; setting this parameter to false will turn off logging.
     The 'allow_none' and 'encoding' parameters are passed on to *note
     xmlrpc.client: 12e. and control the XML-RPC responses that will be
     returned from the server.  The 'bind_and_activate' parameter
     controls whether ‘server_bind()’ and ‘server_activate()’ are called
     immediately by the constructor; it defaults to true.  Setting it to
     false allows code to manipulate the 'allow_reuse_address' class
     variable before the address is bound.  The 'use_builtin_types'
     parameter is passed to the *note loads(): 1483. function and
     controls which types are processed when date/times values or binary
     data are received; it defaults to false.

     Changed in version 3.3: The 'use_builtin_types' flag was added.

 -- Class: xmlrpc.server.CGIXMLRPCRequestHandler (allow_none=False,
          encoding=None, use_builtin_types=False)

     Create a new instance to handle XML-RPC requests in a CGI
     environment.  The 'allow_none' and 'encoding' parameters are passed
     on to *note xmlrpc.client: 12e. and control the XML-RPC responses
     that will be returned from the server.  The 'use_builtin_types'
     parameter is passed to the *note loads(): 1483. function and
     controls which types are processed when date/times values or binary
     data are received; it defaults to false.

     Changed in version 3.3: The 'use_builtin_types' flag was added.

 -- Class: xmlrpc.server.SimpleXMLRPCRequestHandler

     Create a new request handler instance.  This request handler
     supports ‘POST’ requests and modifies logging so that the
     'logRequests' parameter to the *note SimpleXMLRPCServer: 3e7b.
     constructor parameter is honored.

* Menu:

* SimpleXMLRPCServer objects::
* CGIXMLRPCRequestHandler::
* Documenting XMLRPC server::
* DocXMLRPCServer objects::
* DocCGIXMLRPCRequestHandler::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/xmlrpc/server.py


File: python.info,  Node: SimpleXMLRPCServer objects,  Next: CGIXMLRPCRequestHandler,  Up: xmlrpc server — Basic XML-RPC servers

5.22.22.1 SimpleXMLRPCServer objects
....................................

The *note SimpleXMLRPCServer: 3e7b. class is based on *note
socketserver.TCPServer: 1369. and provides a means of creating simple,
stand alone XML-RPC servers.

 -- Method: SimpleXMLRPCServer.register_function (function=None,
          name=None)

     Register a function that can respond to XML-RPC requests.  If
     'name' is given, it will be the method name associated with
     'function', otherwise *note function.__name__: 131c. will be used.
     'name' is a string, and may contain characters not legal in Python
     identifiers, including the period character.

     This method can also be used as a decorator.  When used as a
     decorator, 'name' can only be given as a keyword argument to
     register 'function' under 'name'.  If no 'name' is given, *note
     function.__name__: 131c. will be used.

     Changed in version 3.7: ‘register_function()’ can be used as a
     decorator.

 -- Method: SimpleXMLRPCServer.register_instance (instance,
          allow_dotted_names=False)

     Register an object which is used to expose method names which have
     not been registered using *note register_function(): 3e7f.  If
     'instance' contains a ‘_dispatch()’ method, it is called with the
     requested method name and the parameters from the request.  Its API
     is ‘def _dispatch(self, method, params)’ (note that 'params' does
     not represent a variable argument list).  If it calls an underlying
     function to perform its task, that function is called as
     ‘func(*params)’, expanding the parameter list.  The return value
     from ‘_dispatch()’ is returned to the client as the result.  If
     'instance' does not have a ‘_dispatch()’ method, it is searched for
     an attribute matching the name of the requested method.

     If the optional 'allow_dotted_names' argument is true and the
     instance does not have a ‘_dispatch()’ method, then if the
     requested method name contains periods, each component of the
     method name is searched for individually, with the effect that a
     simple hierarchical search is performed.  The value found from this
     search is then called with the parameters from the request, and the
     return value is passed back to the client.

          Warning: Enabling the 'allow_dotted_names' option allows
          intruders to access your module’s global variables and may
          allow intruders to execute arbitrary code on your machine.
          Only use this option on a secure, closed network.

 -- Method: SimpleXMLRPCServer.register_introspection_functions ()

     Registers the XML-RPC introspection functions ‘system.listMethods’,
     ‘system.methodHelp’ and ‘system.methodSignature’.

 -- Method: SimpleXMLRPCServer.register_multicall_functions ()

     Registers the XML-RPC multicall function system.multicall.

 -- Attribute: SimpleXMLRPCRequestHandler.rpc_paths

     An attribute value that must be a tuple listing valid path portions
     of the URL for receiving XML-RPC requests.  Requests posted to
     other paths will result in a 404 “no such page” HTTP error.  If
     this tuple is empty, all paths will be considered valid.  The
     default value is ‘('/', '/RPC2')’.

* Menu:

* SimpleXMLRPCServer example::


File: python.info,  Node: SimpleXMLRPCServer example,  Up: SimpleXMLRPCServer objects

5.22.22.2 SimpleXMLRPCServer example
....................................

Server code:

     from xmlrpc.server import SimpleXMLRPCServer
     from xmlrpc.server import SimpleXMLRPCRequestHandler

     # Restrict to a particular path.
     class RequestHandler(SimpleXMLRPCRequestHandler):
         rpc_paths = ('/RPC2',)

     # Create server
     with SimpleXMLRPCServer(('localhost', 8000),
                             requestHandler=RequestHandler) as server:
         server.register_introspection_functions()

         # Register pow() function; this will use the value of
         # pow.__name__ as the name, which is just 'pow'.
         server.register_function(pow)

         # Register a function under a different name
         def adder_function(x, y):
             return x + y
         server.register_function(adder_function, 'add')

         # Register an instance; all the methods of the instance are
         # published as XML-RPC methods (in this case, just 'mul').
         class MyFuncs:
             def mul(self, x, y):
                 return x * y

         server.register_instance(MyFuncs())

         # Run the server's main loop
         server.serve_forever()

The following client code will call the methods made available by the
preceding server:

     import xmlrpc.client

     s = xmlrpc.client.ServerProxy('http://localhost:8000')
     print(s.pow(2,3))  # Returns 2**3 = 8
     print(s.add(2,3))  # Returns 5
     print(s.mul(5,2))  # Returns 5*2 = 10

     # Print list of available methods
     print(s.system.listMethods())

‘register_function()’ can also be used as a decorator.  The previous
server example can register functions in a decorator way:

     from xmlrpc.server import SimpleXMLRPCServer
     from xmlrpc.server import SimpleXMLRPCRequestHandler

     class RequestHandler(SimpleXMLRPCRequestHandler):
         rpc_paths = ('/RPC2',)

     with SimpleXMLRPCServer(('localhost', 8000),
                             requestHandler=RequestHandler) as server:
         server.register_introspection_functions()

         # Register pow() function; this will use the value of
         # pow.__name__ as the name, which is just 'pow'.
         server.register_function(pow)

         # Register a function under a different name, using
         # register_function as a decorator. *name* can only be given
         # as a keyword argument.
         @server.register_function(name='add')
         def adder_function(x, y):
             return x + y

         # Register a function under function.__name__.
         @server.register_function
         def mul(x, y):
             return x * y

         server.serve_forever()

The following example included in the ‘Lib/xmlrpc/server.py’ module
shows a server allowing dotted names and registering a multicall
function.

     Warning: Enabling the 'allow_dotted_names' option allows intruders
     to access your module’s global variables and may allow intruders to
     execute arbitrary code on your machine.  Only use this example
     within a secure, closed network.

     import datetime as dt

     class ExampleService:
         def getData(self):
             return '42'

         class currentTime:
             @staticmethod
             def getCurrentTime():
                 return dt.datetime.now()

     with SimpleXMLRPCServer(("localhost", 8000)) as server:
         server.register_function(pow)
         server.register_function(lambda x,y: x+y, 'add')
         server.register_instance(ExampleService(), allow_dotted_names=True)
         server.register_multicall_functions()
         print('Serving XML-RPC on localhost port 8000')
         try:
             server.serve_forever()
         except KeyboardInterrupt:
             print("\nKeyboard interrupt received, exiting.")
             sys.exit(0)

This ExampleService demo can be invoked from the command line:

     python -m xmlrpc.server

The client that interacts with the above server is included in
‘Lib/xmlrpc/client.py’:

     server = ServerProxy("http://localhost:8000")

     try:
         print(server.currentTime.getCurrentTime())
     except Error as v:
         print("ERROR", v)

     multi = MultiCall(server)
     multi.getData()
     multi.pow(2,9)
     multi.add(1,2)
     try:
         for response in multi():
             print(response)
     except Error as v:
         print("ERROR", v)

This client which interacts with the demo XMLRPC server can be invoked
as:

     python -m xmlrpc.client


File: python.info,  Node: CGIXMLRPCRequestHandler,  Next: Documenting XMLRPC server,  Prev: SimpleXMLRPCServer objects,  Up: xmlrpc server — Basic XML-RPC servers

5.22.22.3 CGIXMLRPCRequestHandler
.................................

The *note CGIXMLRPCRequestHandler: 3e7c. class can be used to handle
XML-RPC requests sent to Python CGI scripts.

 -- Method: CGIXMLRPCRequestHandler.register_function (function=None,
          name=None)

     Register a function that can respond to XML-RPC requests.  If
     'name' is given, it will be the method name associated with
     'function', otherwise *note function.__name__: 131c. will be used.
     'name' is a string, and may contain characters not legal in Python
     identifiers, including the period character.

     This method can also be used as a decorator.  When used as a
     decorator, 'name' can only be given as a keyword argument to
     register 'function' under 'name'.  If no 'name' is given, *note
     function.__name__: 131c. will be used.

     Changed in version 3.7: ‘register_function()’ can be used as a
     decorator.

 -- Method: CGIXMLRPCRequestHandler.register_instance (instance)

     Register an object which is used to expose method names which have
     not been registered using *note register_function(): 3e86.  If
     instance contains a ‘_dispatch()’ method, it is called with the
     requested method name and the parameters from the request; the
     return value is returned to the client as the result.  If instance
     does not have a ‘_dispatch()’ method, it is searched for an
     attribute matching the name of the requested method; if the
     requested method name contains periods, each component of the
     method name is searched for individually, with the effect that a
     simple hierarchical search is performed.  The value found from this
     search is then called with the parameters from the request, and the
     return value is passed back to the client.

 -- Method: CGIXMLRPCRequestHandler.register_introspection_functions ()

     Register the XML-RPC introspection functions ‘system.listMethods’,
     ‘system.methodHelp’ and ‘system.methodSignature’.

 -- Method: CGIXMLRPCRequestHandler.register_multicall_functions ()

     Register the XML-RPC multicall function ‘system.multicall’.

 -- Method: CGIXMLRPCRequestHandler.handle_request (request_text=None)

     Handle an XML-RPC request.  If 'request_text' is given, it should
     be the POST data provided by the HTTP server, otherwise the
     contents of stdin will be used.

Example:

     class MyFuncs:
         def mul(self, x, y):
             return x * y


     handler = CGIXMLRPCRequestHandler()
     handler.register_function(pow)
     handler.register_function(lambda x,y: x+y, 'add')
     handler.register_introspection_functions()
     handler.register_instance(MyFuncs())
     handler.handle_request()


File: python.info,  Node: Documenting XMLRPC server,  Next: DocXMLRPCServer objects,  Prev: CGIXMLRPCRequestHandler,  Up: xmlrpc server — Basic XML-RPC servers

5.22.22.4 Documenting XMLRPC server
...................................

These classes extend the above classes to serve HTML documentation in
response to HTTP GET requests.  Servers can either be free standing,
using *note DocXMLRPCServer: 1b4e, or embedded in a CGI environment,
using *note DocCGIXMLRPCRequestHandler: 3e8c.

 -- Class: xmlrpc.server.DocXMLRPCServer (addr,
          requestHandler=DocXMLRPCRequestHandler, logRequests=True,
          allow_none=False, encoding=None, bind_and_activate=True,
          use_builtin_types=True)

     Create a new server instance.  All parameters have the same meaning
     as for *note SimpleXMLRPCServer: 3e7b.; 'requestHandler' defaults
     to *note DocXMLRPCRequestHandler: 3e8d.

     Changed in version 3.3: The 'use_builtin_types' flag was added.

 -- Class: xmlrpc.server.DocCGIXMLRPCRequestHandler

     Create a new instance to handle XML-RPC requests in a CGI
     environment.

 -- Class: xmlrpc.server.DocXMLRPCRequestHandler

     Create a new request handler instance.  This request handler
     supports XML-RPC POST requests, documentation GET requests, and
     modifies logging so that the 'logRequests' parameter to the *note
     DocXMLRPCServer: 1b4e. constructor parameter is honored.


File: python.info,  Node: DocXMLRPCServer objects,  Next: DocCGIXMLRPCRequestHandler,  Prev: Documenting XMLRPC server,  Up: xmlrpc server — Basic XML-RPC servers

5.22.22.5 DocXMLRPCServer objects
.................................

The *note DocXMLRPCServer: 1b4e. class is derived from *note
SimpleXMLRPCServer: 3e7b. and provides a means of creating
self-documenting, stand alone XML-RPC servers.  HTTP POST requests are
handled as XML-RPC method calls.  HTTP GET requests are handled by
generating pydoc-style HTML documentation.  This allows a server to
provide its own web-based documentation.

 -- Method: DocXMLRPCServer.set_server_title (server_title)

     Set the title used in the generated HTML documentation.  This title
     will be used inside the HTML “title” element.

 -- Method: DocXMLRPCServer.set_server_name (server_name)

     Set the name used in the generated HTML documentation.  This name
     will appear at the top of the generated documentation inside a “h1”
     element.

 -- Method: DocXMLRPCServer.set_server_documentation
          (server_documentation)

     Set the description used in the generated HTML documentation.  This
     description will appear as a paragraph, below the server name, in
     the documentation.


File: python.info,  Node: DocCGIXMLRPCRequestHandler,  Prev: DocXMLRPCServer objects,  Up: xmlrpc server — Basic XML-RPC servers

5.22.22.6 DocCGIXMLRPCRequestHandler
....................................

The *note DocCGIXMLRPCRequestHandler: 3e8c. class is derived from *note
CGIXMLRPCRequestHandler: 3e7c. and provides a means of creating
self-documenting, XML-RPC CGI scripts.  HTTP POST requests are handled
as XML-RPC method calls.  HTTP GET requests are handled by generating
pydoc-style HTML documentation.  This allows a server to provide its own
web-based documentation.

 -- Method: DocCGIXMLRPCRequestHandler.set_server_title (server_title)

     Set the title used in the generated HTML documentation.  This title
     will be used inside the HTML “title” element.

 -- Method: DocCGIXMLRPCRequestHandler.set_server_name (server_name)

     Set the name used in the generated HTML documentation.  This name
     will appear at the top of the generated documentation inside a “h1”
     element.

 -- Method: DocCGIXMLRPCRequestHandler.set_server_documentation
          (server_documentation)

     Set the description used in the generated HTML documentation.  This
     description will appear as a paragraph, below the server name, in
     the documentation.


File: python.info,  Node: ipaddress — IPv4/IPv6 manipulation library,  Prev: xmlrpc server — Basic XML-RPC servers,  Up: Internet Protocols and Support

5.22.23 ‘ipaddress’ — IPv4/IPv6 manipulation library
----------------------------------------------------

'Source code:' Lib/ipaddress.py(1)

__________________________________________________________________

‘ipaddress’ provides the capabilities to create, manipulate and operate
on IPv4 and IPv6 addresses and networks.

The functions and classes in this module make it straightforward to
handle various tasks related to IP addresses, including checking whether
or not two hosts are on the same subnet, iterating over all hosts in a
particular subnet, checking whether or not a string represents a valid
IP address or network definition, and so on.

This is the full module API reference—for an overview and introduction,
see *note An introduction to the ipaddress module: 3e9a.

Added in version 3.3.

* Menu:

* Convenience factory functions::
* IP Addresses::
* IP Network definitions::
* Interface objects::
* Other Module Level Functions::
* Custom Exceptions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ipaddress.py


File: python.info,  Node: Convenience factory functions,  Next: IP Addresses,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.1 Convenience factory functions
.......................................

The ‘ipaddress’ module provides factory functions to conveniently create
IP addresses, networks and interfaces:

 -- Function: ipaddress.ip_address (address)

     Return an *note IPv4Address: 1fc. or *note IPv6Address: 1fd. object
     depending on the IP address passed as argument.  Either IPv4 or
     IPv6 addresses may be supplied; integers less than ‘2**32’ will be
     considered to be IPv4 by default.  A *note ValueError: 202. is
     raised if 'address' does not represent a valid IPv4 or IPv6
     address.

          >>> ipaddress.ip_address('192.168.0.1')
          IPv4Address('192.168.0.1')
          >>> ipaddress.ip_address('2001:db8::')
          IPv6Address('2001:db8::')

 -- Function: ipaddress.ip_network (address, strict=True)

     Return an *note IPv4Network: 1fe. or *note IPv6Network: 1ff. object
     depending on the IP address passed as argument.  'address' is a
     string or integer representing the IP network.  Either IPv4 or IPv6
     networks may be supplied; integers less than ‘2**32’ will be
     considered to be IPv4 by default.  'strict' is passed to
     ‘IPv4Network’ or ‘IPv6Network’ constructor.  A *note ValueError:
     202. is raised if 'address' does not represent a valid IPv4 or IPv6
     address, or if the network has host bits set.

          >>> ipaddress.ip_network('192.168.0.0/28')
          IPv4Network('192.168.0.0/28')

 -- Function: ipaddress.ip_interface (address)

     Return an *note IPv4Interface: 193f. or *note IPv6Interface: 1940.
     object depending on the IP address passed as argument.  'address'
     is a string or integer representing the IP address.  Either IPv4 or
     IPv6 addresses may be supplied; integers less than ‘2**32’ will be
     considered to be IPv4 by default.  A *note ValueError: 202. is
     raised if 'address' does not represent a valid IPv4 or IPv6
     address.

One downside of these convenience functions is that the need to handle
both IPv4 and IPv6 formats means that error messages provide minimal
information on the precise error, as the functions don’t know whether
the IPv4 or IPv6 format was intended.  More detailed error reporting can
be obtained by calling the appropriate version specific class
constructors directly.


File: python.info,  Node: IP Addresses,  Next: IP Network definitions,  Prev: Convenience factory functions,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.2 IP Addresses
......................

* Menu:

* Address objects::
* Conversion to Strings and Integers::
* Operators: Operators<3>.


File: python.info,  Node: Address objects,  Next: Conversion to Strings and Integers,  Up: IP Addresses

5.22.23.3 Address objects
.........................

The *note IPv4Address: 1fc. and *note IPv6Address: 1fd. objects share a
lot of common attributes.  Some attributes that are only meaningful for
IPv6 addresses are also implemented by ‘IPv4Address’ objects, in order
to make it easier to write code that handles both IP versions correctly.
Address objects are *note hashable: 613, so they can be used as keys in
dictionaries.

 -- Class: ipaddress.IPv4Address (address)

     Construct an IPv4 address.  An *note AddressValueError: 3ea1. is
     raised if 'address' is not a valid IPv4 address.

     The following constitutes a valid IPv4 address:

       1. A string in decimal-dot notation, consisting of four decimal
          integers in the inclusive range 0–255, separated by dots (e.g.
          ‘192.168.0.1’).  Each integer represents an octet (byte) in
          the address.  Leading zeroes are not tolerated to prevent
          confusion with octal notation.

       2. An integer that fits into 32 bits.

       3. An integer packed into a *note bytes: 1c2. object of length 4
          (most significant octet first).

          >>> ipaddress.IPv4Address('192.168.0.1')
          IPv4Address('192.168.0.1')
          >>> ipaddress.IPv4Address(3232235521)
          IPv4Address('192.168.0.1')
          >>> ipaddress.IPv4Address(b'\xC0\xA8\x00\x01')
          IPv4Address('192.168.0.1')

     Changed in version 3.8: Leading zeros are tolerated, even in
     ambiguous cases that look like octal notation.

     Changed in version 3.9.5: Leading zeros are no longer tolerated and
     are treated as an error.  IPv4 address strings are now parsed as
     strict as glibc *note inet_pton(): 96c.

      -- Attribute: version

          The appropriate version number: ‘4’ for IPv4, ‘6’ for IPv6.

      -- Attribute: max_prefixlen

          The total number of bits in the address representation for
          this version: ‘32’ for IPv4, ‘128’ for IPv6.

          The prefix defines the number of leading bits in an address
          that are compared to determine whether or not an address is
          part of a network.

      -- Attribute: compressed

      -- Attribute: exploded

          The string representation in dotted decimal notation.  Leading
          zeroes are never included in the representation.

          As IPv4 does not define a shorthand notation for addresses
          with octets set to zero, these two attributes are always the
          same as ‘str(addr)’ for IPv4 addresses.  Exposing these
          attributes makes it easier to write display code that can
          handle both IPv4 and IPv6 addresses.

      -- Attribute: packed

          The binary representation of this address - a *note bytes:
          1c2. object of the appropriate length (most significant octet
          first).  This is 4 bytes for IPv4 and 16 bytes for IPv6.

      -- Attribute: reverse_pointer

          The name of the reverse DNS PTR record for the IP address,
          e.g.:

               >>> ipaddress.ip_address("127.0.0.1").reverse_pointer
               '1.0.0.127.in-addr.arpa'
               >>> ipaddress.ip_address("2001:db8::1").reverse_pointer
               '1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa'

          This is the name that could be used for performing a PTR
          lookup, not the resolved hostname itself.

          Added in version 3.5.

      -- Attribute: is_multicast

          ‘True’ if the address is reserved for multicast use.  See RFC
          3171(1) (for IPv4) or RFC 2373(2) (for IPv6).

      -- Attribute: is_private

          ‘True’ if the address is defined as not globally reachable by
          iana-ipv4-special-registry(3) (for IPv4) or
          iana-ipv6-special-registry(4) (for IPv6) with the following
          exceptions:

             * ‘is_private’ is ‘False’ for the shared address space
               (‘100.64.0.0/10’)

             * For IPv4-mapped IPv6-addresses the ‘is_private’ value is
               determined by the semantics of the underlying IPv4
               addresses and the following condition holds (see *note
               IPv6Address.ipv4_mapped: 3ea8.):

                    address.is_private == address.ipv4_mapped.is_private

          ‘is_private’ has value opposite to *note is_global: f98,
          except for the shared address space (‘100.64.0.0/10’ range)
          where they are both ‘False’.

          Changed in version 3.13: Fixed some false positives and false
          negatives.

             * ‘192.0.0.0/24’ is considered private with the exception
               of ‘192.0.0.9/32’ and ‘192.0.0.10/32’ (previously: only
               the ‘192.0.0.0/29’ sub-range was considered private).

             * ‘64:ff9b:1::/48’ is considered private.

             * ‘2002::/16’ is considered private.

             * There are exceptions within ‘2001::/23’ (otherwise
               considered private): ‘2001:1::1/128’, ‘2001:1::2/128’,
               ‘2001:3::/32’, ‘2001:4:112::/48’, ‘2001:20::/28’,
               ‘2001:30::/28’.  The exceptions are not considered
               private.

      -- Attribute: is_global

          ‘True’ if the address is defined as globally reachable by
          iana-ipv4-special-registry(5) (for IPv4) or
          iana-ipv6-special-registry(6) (for IPv6) with the following
          exception:

          For IPv4-mapped IPv6-addresses the ‘is_private’ value is
          determined by the semantics of the underlying IPv4 addresses
          and the following condition holds (see *note
          IPv6Address.ipv4_mapped: 3ea8.):

               address.is_global == address.ipv4_mapped.is_global

          ‘is_global’ has value opposite to *note is_private: 1757,
          except for the shared address space (‘100.64.0.0/10’ range)
          where they are both ‘False’.

          Added in version 3.4.

          Changed in version 3.13: Fixed some false positives and false
          negatives, see *note is_private: 1757. for details.

      -- Attribute: is_unspecified

          ‘True’ if the address is unspecified.  See RFC 5735(7) (for
          IPv4) or RFC 2373(8) (for IPv6).

      -- Attribute: is_reserved

          ‘True’ if the address is noted as reserved by the IETF. For
          IPv4, this is only ‘240.0.0.0/4’, the ‘Reserved’ address
          block.  For IPv6, this is all addresses allocated(9) as
          ‘Reserved by IETF’ for future use.

               Note: For IPv4, ‘is_reserved’ is not related to the
               address block value of the ‘Reserved-by-Protocol’ column
               in iana-ipv4-special-registry(10).

               Caution: For IPv6, ‘fec0::/10’ a former Site-Local scoped
               address prefix is currently excluded from that list (see
               *note is_site_local: 3eab. & RFC 3879(11)).

      -- Attribute: is_loopback

          ‘True’ if this is a loopback address.  See RFC 3330(12) (for
          IPv4) or RFC 2373(13) (for IPv6).

      -- Attribute: is_link_local

          ‘True’ if the address is reserved for link-local usage.  See
          RFC 3927(14).

      -- Attribute: ipv6_mapped

          ‘IPv4Address’ object representing the IPv4-mapped IPv6
          address.  See RFC 4291(15).

          Added in version 3.13.

 -- Method: IPv4Address.__format__ (fmt)

     Returns a string representation of the IP address, controlled by an
     explicit format string.  'fmt' can be one of the following: ‘'s'’,
     the default option, equivalent to *note str(): 44f, ‘'b'’ for a
     zero-padded binary string, ‘'X'’ or ‘'x'’ for an uppercase or
     lowercase hexadecimal representation, or ‘'n'’, which is equivalent
     to ‘'b'’ for IPv4 addresses and ‘'x'’ for IPv6.  For binary and
     hexadecimal representations, the form specifier ‘'#'’ and the
     grouping option ‘'_'’ are available.  ‘__format__’ is used by
     ‘format’, ‘str.format’ and f-strings.

          >>> format(ipaddress.IPv4Address('192.168.0.1'))
          '192.168.0.1'
          >>> '{:#b}'.format(ipaddress.IPv4Address('192.168.0.1'))
          '0b11000000101010000000000000000001'
          >>> f'{ipaddress.IPv6Address("2001:db8::1000"):s}'
          '2001:db8::1000'
          >>> format(ipaddress.IPv6Address('2001:db8::1000'), '_X')
          '2001_0DB8_0000_0000_0000_0000_0000_1000'
          >>> '{:#_n}'.format(ipaddress.IPv6Address('2001:db8::1000'))
          '0x2001_0db8_0000_0000_0000_0000_0000_1000'

     Added in version 3.9.

 -- Class: ipaddress.IPv6Address (address)

     Construct an IPv6 address.  An *note AddressValueError: 3ea1. is
     raised if 'address' is not a valid IPv6 address.

     The following constitutes a valid IPv6 address:

       1. A string consisting of eight groups of four hexadecimal
          digits, each group representing 16 bits.  The groups are
          separated by colons.  This describes an 'exploded' (longhand)
          notation.  The string can also be 'compressed' (shorthand
          notation) by various means.  See RFC 4291(16) for details.
          For example, ‘"0000:0000:0000:0000:0000:0abc:0007:0def"’ can
          be compressed to ‘"::abc:7:def"’.

          Optionally, the string may also have a scope zone ID,
          expressed with a suffix ‘%scope_id’.  If present, the scope ID
          must be non-empty, and may not contain ‘%’.  See RFC 4007(17)
          for details.  For example, ‘fe80::1234%1’ might identify
          address ‘fe80::1234’ on the first link of the node.

       2. An integer that fits into 128 bits.

       3. An integer packed into a *note bytes: 1c2. object of length
          16, big-endian.

          >>> ipaddress.IPv6Address('2001:db8::1000')
          IPv6Address('2001:db8::1000')
          >>> ipaddress.IPv6Address('ff02::5678%1')
          IPv6Address('ff02::5678%1')

      -- Attribute: compressed

     The short form of the address representation, with leading zeroes
     in groups omitted and the longest sequence of groups consisting
     entirely of zeroes collapsed to a single empty group.

     This is also the value returned by ‘str(addr)’ for IPv6 addresses.

      -- Attribute: exploded

     The long form of the address representation, with all leading
     zeroes and groups consisting entirely of zeroes included.

     For the following attributes and methods, see the corresponding
     documentation of the *note IPv4Address: 1fc. class:

      -- Attribute: packed

      -- Attribute: reverse_pointer

      -- Attribute: version

      -- Attribute: max_prefixlen

      -- Attribute: is_multicast

      -- Attribute: is_private

      -- Attribute: is_global

          Added in version 3.4.

      -- Attribute: is_unspecified

      -- Attribute: is_reserved

      -- Attribute: is_loopback

      -- Attribute: is_link_local

      -- Attribute: is_site_local

          ‘True’ if the address is reserved for site-local usage.  Note
          that the site-local address space has been deprecated by RFC
          3879(18).  Use *note is_private: 1757. to test if this address
          is in the space of unique local addresses as defined by RFC
          4193(19).

      -- Attribute: ipv4_mapped

          For addresses that appear to be IPv4 mapped addresses
          (starting with ‘::FFFF/96’), this property will report the
          embedded IPv4 address.  For any other address, this property
          will be ‘None’.

      -- Attribute: scope_id

          For scoped addresses as defined by RFC 4007(20), this property
          identifies the particular zone of the address’s scope that the
          address belongs to, as a string.  When no scope zone is
          specified, this property will be ‘None’.

      -- Attribute: sixtofour

          For addresses that appear to be 6to4 addresses (starting with
          ‘2002::/16’) as defined by RFC 3056(21), this property will
          report the embedded IPv4 address.  For any other address, this
          property will be ‘None’.

      -- Attribute: teredo

          For addresses that appear to be Teredo addresses (starting
          with ‘2001::/32’) as defined by RFC 4380(22), this property
          will report the embedded ‘(server, client)’ IP address pair.
          For any other address, this property will be ‘None’.

 -- Method: IPv6Address.__format__ (fmt)

     Refer to the corresponding method documentation in *note
     IPv4Address: 1fc.

     Added in version 3.9.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3171.html

   (2) https://datatracker.ietf.org/doc/html/rfc2373.html

   (3) 
https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml

   (4) 
https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml

   (5) 
https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml

   (6) 
https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml

   (7) https://datatracker.ietf.org/doc/html/rfc5735.html

   (8) https://datatracker.ietf.org/doc/html/rfc2373.html

   (9) 
https://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml

   (10) 
https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml

   (11) https://datatracker.ietf.org/doc/html/rfc3879.html

   (12) https://datatracker.ietf.org/doc/html/rfc3330.html

   (13) https://datatracker.ietf.org/doc/html/rfc2373.html

   (14) https://datatracker.ietf.org/doc/html/rfc3927.html

   (15) https://datatracker.ietf.org/doc/html/rfc4291.html

   (16) https://datatracker.ietf.org/doc/html/rfc4291.html

   (17) https://datatracker.ietf.org/doc/html/rfc4007.html

   (18) https://datatracker.ietf.org/doc/html/rfc3879.html

   (19) https://datatracker.ietf.org/doc/html/rfc4193.html

   (20) https://datatracker.ietf.org/doc/html/rfc4007.html

   (21) https://datatracker.ietf.org/doc/html/rfc3056.html

   (22) https://datatracker.ietf.org/doc/html/rfc4380.html


File: python.info,  Node: Conversion to Strings and Integers,  Next: Operators<3>,  Prev: Address objects,  Up: IP Addresses

5.22.23.4 Conversion to Strings and Integers
............................................

To interoperate with networking interfaces such as the socket module,
addresses must be converted to strings or integers.  This is handled
using the *note str(): 44f. and *note int(): 257. builtin functions:

     >>> str(ipaddress.IPv4Address('192.168.0.1'))
     '192.168.0.1'
     >>> int(ipaddress.IPv4Address('192.168.0.1'))
     3232235521
     >>> str(ipaddress.IPv6Address('::1'))
     '::1'
     >>> int(ipaddress.IPv6Address('::1'))
     1

Note that IPv6 scoped addresses are converted to integers without scope
zone ID.


File: python.info,  Node: Operators<3>,  Prev: Conversion to Strings and Integers,  Up: IP Addresses

5.22.23.5 Operators
...................

Address objects support some operators.  Unless stated otherwise,
operators can only be applied between compatible objects (i.e.  IPv4
with IPv4, IPv6 with IPv6).

* Menu:

* Comparison operators::
* Arithmetic operators::


File: python.info,  Node: Comparison operators,  Next: Arithmetic operators,  Up: Operators<3>

5.22.23.6 Comparison operators
..............................

Address objects can be compared with the usual set of comparison
operators.  Same IPv6 addresses with different scope zone IDs are not
equal.  Some examples:

     >>> IPv4Address('127.0.0.2') > IPv4Address('127.0.0.1')
     True
     >>> IPv4Address('127.0.0.2') == IPv4Address('127.0.0.1')
     False
     >>> IPv4Address('127.0.0.2') != IPv4Address('127.0.0.1')
     True
     >>> IPv6Address('fe80::1234') == IPv6Address('fe80::1234%1')
     False
     >>> IPv6Address('fe80::1234%1') != IPv6Address('fe80::1234%2')
     True


File: python.info,  Node: Arithmetic operators,  Prev: Comparison operators,  Up: Operators<3>

5.22.23.7 Arithmetic operators
..............................

Integers can be added to or subtracted from address objects.  Some
examples:

     >>> IPv4Address('127.0.0.2') + 3
     IPv4Address('127.0.0.5')
     >>> IPv4Address('127.0.0.2') - 3
     IPv4Address('126.255.255.255')
     >>> IPv4Address('255.255.255.255') + 1
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ipaddress.AddressValueError: 4294967296 (>= 2**32) is not permitted as an IPv4 address


File: python.info,  Node: IP Network definitions,  Next: Interface objects,  Prev: IP Addresses,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.8 IP Network definitions
................................

The *note IPv4Network: 1fe. and *note IPv6Network: 1ff. objects provide
a mechanism for defining and inspecting IP network definitions.  A
network definition consists of a 'mask' and a 'network address', and as
such defines a range of IP addresses that equal the network address when
masked (binary AND) with the mask.  For example, a network definition
with the mask ‘255.255.255.0’ and the network address ‘192.168.1.0’
consists of IP addresses in the inclusive range ‘192.168.1.0’ to
‘192.168.1.255’.

* Menu:

* Prefix, net mask and host mask: Prefix net mask and host mask.
* Network objects::
* Operators: Operators<4>.


File: python.info,  Node: Prefix net mask and host mask,  Next: Network objects,  Up: IP Network definitions

5.22.23.9 Prefix, net mask and host mask
........................................

There are several equivalent ways to specify IP network masks.  A
'prefix' ‘/<nbits>’ is a notation that denotes how many high-order bits
are set in the network mask.  A 'net mask' is an IP address with some
number of high-order bits set.  Thus the prefix ‘/24’ is equivalent to
the net mask ‘255.255.255.0’ in IPv4, or ‘ffff:ff00::’ in IPv6.  In
addition, a 'host mask' is the logical inverse of a 'net mask', and is
sometimes used (for example in Cisco access control lists) to denote a
network mask.  The host mask equivalent to ‘/24’ in IPv4 is ‘0.0.0.255’.


File: python.info,  Node: Network objects,  Next: Operators<4>,  Prev: Prefix net mask and host mask,  Up: IP Network definitions

5.22.23.10 Network objects
..........................

All attributes implemented by address objects are implemented by network
objects as well.  In addition, network objects implement additional
attributes.  All of these are common between *note IPv4Network: 1fe. and
*note IPv6Network: 1ff, so to avoid duplication they are only documented
for ‘IPv4Network’.  Network objects are *note hashable: 613, so they can
be used as keys in dictionaries.

 -- Class: ipaddress.IPv4Network (address, strict=True)

     Construct an IPv4 network definition.  'address' can be one of the
     following:

       1. A string consisting of an IP address and an optional mask,
          separated by a slash (‘/’).  The IP address is the network
          address, and the mask can be either a single number, which
          means it’s a 'prefix', or a string representation of an IPv4
          address.  If it’s the latter, the mask is interpreted as a
          'net mask' if it starts with a non-zero field, or as a 'host
          mask' if it starts with a zero field, with the single
          exception of an all-zero mask which is treated as a 'net
          mask'.  If no mask is provided, it’s considered to be ‘/32’.

          For example, the following 'address' specifications are
          equivalent: ‘192.168.1.0/24’, ‘192.168.1.0/255.255.255.0’ and
          ‘192.168.1.0/0.0.0.255’.

       2. An integer that fits into 32 bits.  This is equivalent to a
          single-address network, with the network address being
          'address' and the mask being ‘/32’.

       3. An integer packed into a *note bytes: 1c2. object of length 4,
          big-endian.  The interpretation is similar to an integer
          'address'.

       4. A two-tuple of an address description and a netmask, where the
          address description is either a string, a 32-bits integer, a
          4-bytes packed integer, or an existing IPv4Address object; and
          the netmask is either an integer representing the prefix
          length (e.g.  ‘24’) or a string representing the prefix mask
          (e.g.  ‘255.255.255.0’).

     An *note AddressValueError: 3ea1. is raised if 'address' is not a
     valid IPv4 address.  A *note NetmaskValueError: 3ec2. is raised if
     the mask is not valid for an IPv4 address.

     If 'strict' is ‘True’ and host bits are set in the supplied
     address, then *note ValueError: 202. is raised.  Otherwise, the
     host bits are masked out to determine the appropriate network
     address.

     Unless stated otherwise, all network methods accepting other
     network/address objects will raise *note TypeError: 2c3. if the
     argument’s IP version is incompatible to ‘self’.

     Changed in version 3.5: Added the two-tuple form for the 'address'
     constructor parameter.

      -- Attribute: version

      -- Attribute: max_prefixlen

          Refer to the corresponding attribute documentation in *note
          IPv4Address: 1fc.

      -- Attribute: is_multicast

      -- Attribute: is_private

      -- Attribute: is_unspecified

      -- Attribute: is_reserved

      -- Attribute: is_loopback

      -- Attribute: is_link_local

          These attributes are true for the network as a whole if they
          are true for both the network address and the broadcast
          address.

      -- Attribute: network_address

          The network address for the network.  The network address and
          the prefix length together uniquely define a network.

      -- Attribute: broadcast_address

          The broadcast address for the network.  Packets sent to the
          broadcast address should be received by every host on the
          network.

      -- Attribute: hostmask

          The host mask, as an *note IPv4Address: 1fc. object.

      -- Attribute: netmask

          The net mask, as an *note IPv4Address: 1fc. object.

      -- Attribute: with_prefixlen

      -- Attribute: compressed

      -- Attribute: exploded

          A string representation of the network, with the mask in
          prefix notation.

          ‘with_prefixlen’ and ‘compressed’ are always the same as
          ‘str(network)’.  ‘exploded’ uses the exploded form the network
          address.

      -- Attribute: with_netmask

          A string representation of the network, with the mask in net
          mask notation.

      -- Attribute: with_hostmask

          A string representation of the network, with the mask in host
          mask notation.

      -- Attribute: num_addresses

          The total number of addresses in the network.

      -- Attribute: prefixlen

          Length of the network prefix, in bits.

      -- Method: hosts ()

          Returns an iterator over the usable hosts in the network.  The
          usable hosts are all the IP addresses that belong to the
          network, except the network address itself and the network
          broadcast address.  For networks with a mask length of 31, the
          network address and network broadcast address are also
          included in the result.  Networks with a mask of 32 will
          return a list containing the single host address.

               >>> list(ip_network('192.0.2.0/29').hosts())
               [IPv4Address('192.0.2.1'), IPv4Address('192.0.2.2'),
                IPv4Address('192.0.2.3'), IPv4Address('192.0.2.4'),
                IPv4Address('192.0.2.5'), IPv4Address('192.0.2.6')]
               >>> list(ip_network('192.0.2.0/31').hosts())
               [IPv4Address('192.0.2.0'), IPv4Address('192.0.2.1')]
               >>> list(ip_network('192.0.2.1/32').hosts())
               [IPv4Address('192.0.2.1')]

      -- Method: overlaps (other)

          ‘True’ if this network is partly or wholly contained in
          'other' or 'other' is wholly contained in this network.

      -- Method: address_exclude (network)

          Computes the network definitions resulting from removing the
          given 'network' from this one.  Returns an iterator of network
          objects.  Raises *note ValueError: 202. if 'network' is not
          completely contained in this network.

               >>> n1 = ip_network('192.0.2.0/28')
               >>> n2 = ip_network('192.0.2.1/32')
               >>> list(n1.address_exclude(n2))
               [IPv4Network('192.0.2.8/29'), IPv4Network('192.0.2.4/30'),
                IPv4Network('192.0.2.2/31'), IPv4Network('192.0.2.0/32')]

      -- Method: subnets (prefixlen_diff=1, new_prefix=None)

          The subnets that join to make the current network definition,
          depending on the argument values.  'prefixlen_diff' is the
          amount our prefix length should be increased by.  'new_prefix'
          is the desired new prefix of the subnets; it must be larger
          than our prefix.  One and only one of 'prefixlen_diff' and
          'new_prefix' must be set.  Returns an iterator of network
          objects.

               >>> list(ip_network('192.0.2.0/24').subnets())
               [IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/25')]
               >>> list(ip_network('192.0.2.0/24').subnets(prefixlen_diff=2))
               [IPv4Network('192.0.2.0/26'), IPv4Network('192.0.2.64/26'),
                IPv4Network('192.0.2.128/26'), IPv4Network('192.0.2.192/26')]
               >>> list(ip_network('192.0.2.0/24').subnets(new_prefix=26))
               [IPv4Network('192.0.2.0/26'), IPv4Network('192.0.2.64/26'),
                IPv4Network('192.0.2.128/26'), IPv4Network('192.0.2.192/26')]
               >>> list(ip_network('192.0.2.0/24').subnets(new_prefix=23))
               Traceback (most recent call last):
                 File "<stdin>", line 1, in <module>
                   raise ValueError('new prefix must be longer')
               ValueError: new prefix must be longer
               >>> list(ip_network('192.0.2.0/24').subnets(new_prefix=25))
               [IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/25')]

      -- Method: supernet (prefixlen_diff=1, new_prefix=None)

          The supernet containing this network definition, depending on
          the argument values.  'prefixlen_diff' is the amount our
          prefix length should be decreased by.  'new_prefix' is the
          desired new prefix of the supernet; it must be smaller than
          our prefix.  One and only one of 'prefixlen_diff' and
          'new_prefix' must be set.  Returns a single network object.

               >>> ip_network('192.0.2.0/24').supernet()
               IPv4Network('192.0.2.0/23')
               >>> ip_network('192.0.2.0/24').supernet(prefixlen_diff=2)
               IPv4Network('192.0.0.0/22')
               >>> ip_network('192.0.2.0/24').supernet(new_prefix=20)
               IPv4Network('192.0.0.0/20')

      -- Method: subnet_of (other)

          Return ‘True’ if this network is a subnet of 'other'.

               >>> a = ip_network('192.168.1.0/24')
               >>> b = ip_network('192.168.1.128/30')
               >>> b.subnet_of(a)
               True

          Added in version 3.7.

      -- Method: supernet_of (other)

          Return ‘True’ if this network is a supernet of 'other'.

               >>> a = ip_network('192.168.1.0/24')
               >>> b = ip_network('192.168.1.128/30')
               >>> a.supernet_of(b)
               True

          Added in version 3.7.

      -- Method: compare_networks (other)

          Compare this network to 'other'.  In this comparison only the
          network addresses are considered; host bits aren’t.  Returns
          either ‘-1’, ‘0’ or ‘1’.

               >>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.2/32'))
               -1
               >>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.0/32'))
               1
               >>> ip_network('192.0.2.1/32').compare_networks(ip_network('192.0.2.1/32'))
               0

          Deprecated since version 3.7: It uses the same ordering and
          comparison algorithm as “<”, “==”, and “>”

 -- Class: ipaddress.IPv6Network (address, strict=True)

     Construct an IPv6 network definition.  'address' can be one of the
     following:

       1. A string consisting of an IP address and an optional prefix
          length, separated by a slash (‘/’).  The IP address is the
          network address, and the prefix length must be a single
          number, the 'prefix'.  If no prefix length is provided, it’s
          considered to be ‘/128’.

          Note that currently expanded netmasks are not supported.  That
          means ‘2001:db00::0/24’ is a valid argument while
          ‘2001:db00::0/ffff:ff00::’ is not.

       2. An integer that fits into 128 bits.  This is equivalent to a
          single-address network, with the network address being
          'address' and the mask being ‘/128’.

       3. An integer packed into a *note bytes: 1c2. object of length
          16, big-endian.  The interpretation is similar to an integer
          'address'.

       4. A two-tuple of an address description and a netmask, where the
          address description is either a string, a 128-bits integer, a
          16-bytes packed integer, or an existing IPv6Address object;
          and the netmask is an integer representing the prefix length.

     An *note AddressValueError: 3ea1. is raised if 'address' is not a
     valid IPv6 address.  A *note NetmaskValueError: 3ec2. is raised if
     the mask is not valid for an IPv6 address.

     If 'strict' is ‘True’ and host bits are set in the supplied
     address, then *note ValueError: 202. is raised.  Otherwise, the
     host bits are masked out to determine the appropriate network
     address.

     Changed in version 3.5: Added the two-tuple form for the 'address'
     constructor parameter.

      -- Attribute: version

      -- Attribute: max_prefixlen

      -- Attribute: is_multicast

      -- Attribute: is_private

      -- Attribute: is_unspecified

      -- Attribute: is_reserved

      -- Attribute: is_loopback

      -- Attribute: is_link_local

      -- Attribute: network_address

      -- Attribute: broadcast_address

      -- Attribute: hostmask

      -- Attribute: netmask

      -- Attribute: with_prefixlen

      -- Attribute: compressed

      -- Attribute: exploded

      -- Attribute: with_netmask

      -- Attribute: with_hostmask

      -- Attribute: num_addresses

      -- Attribute: prefixlen

      -- Method: hosts ()

          Returns an iterator over the usable hosts in the network.  The
          usable hosts are all the IP addresses that belong to the
          network, except the Subnet-Router anycast address.  For
          networks with a mask length of 127, the Subnet-Router anycast
          address is also included in the result.  Networks with a mask
          of 128 will return a list containing the single host address.

      -- Method: overlaps (other)

      -- Method: address_exclude (network)

      -- Method: subnets (prefixlen_diff=1, new_prefix=None)

      -- Method: supernet (prefixlen_diff=1, new_prefix=None)

      -- Method: subnet_of (other)

      -- Method: supernet_of (other)

      -- Method: compare_networks (other)

          Refer to the corresponding attribute documentation in *note
          IPv4Network: 1fe.

      -- Attribute: is_site_local

          These attribute is true for the network as a whole if it is
          true for both the network address and the broadcast address.


File: python.info,  Node: Operators<4>,  Prev: Network objects,  Up: IP Network definitions

5.22.23.11 Operators
....................

Network objects support some operators.  Unless stated otherwise,
operators can only be applied between compatible objects (i.e.  IPv4
with IPv4, IPv6 with IPv6).

* Menu:

* Logical operators::
* Iteration::
* Networks as containers of addresses::


File: python.info,  Node: Logical operators,  Next: Iteration,  Up: Operators<4>

5.22.23.12 Logical operators
............................

Network objects can be compared with the usual set of logical operators.
Network objects are ordered first by network address, then by net mask.


File: python.info,  Node: Iteration,  Next: Networks as containers of addresses,  Prev: Logical operators,  Up: Operators<4>

5.22.23.13 Iteration
....................

Network objects can be iterated to list all the addresses belonging to
the network.  For iteration, 'all' hosts are returned, including
unusable hosts (for usable hosts, use the *note hosts(): 15f6. method).
An example:

     >>> for addr in IPv4Network('192.0.2.0/28'):
     ...     addr
     ...
     IPv4Address('192.0.2.0')
     IPv4Address('192.0.2.1')
     IPv4Address('192.0.2.2')
     IPv4Address('192.0.2.3')
     IPv4Address('192.0.2.4')
     IPv4Address('192.0.2.5')
     IPv4Address('192.0.2.6')
     IPv4Address('192.0.2.7')
     IPv4Address('192.0.2.8')
     IPv4Address('192.0.2.9')
     IPv4Address('192.0.2.10')
     IPv4Address('192.0.2.11')
     IPv4Address('192.0.2.12')
     IPv4Address('192.0.2.13')
     IPv4Address('192.0.2.14')
     IPv4Address('192.0.2.15')


File: python.info,  Node: Networks as containers of addresses,  Prev: Iteration,  Up: Operators<4>

5.22.23.14 Networks as containers of addresses
..............................................

Network objects can act as containers of addresses.  Some examples:

     >>> IPv4Network('192.0.2.0/28')[0]
     IPv4Address('192.0.2.0')
     >>> IPv4Network('192.0.2.0/28')[15]
     IPv4Address('192.0.2.15')
     >>> IPv4Address('192.0.2.6') in IPv4Network('192.0.2.0/28')
     True
     >>> IPv4Address('192.0.3.6') in IPv4Network('192.0.2.0/28')
     False


File: python.info,  Node: Interface objects,  Next: Other Module Level Functions,  Prev: IP Network definitions,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.15 Interface objects
............................

Interface objects are *note hashable: 613, so they can be used as keys
in dictionaries.

 -- Class: ipaddress.IPv4Interface (address)

     Construct an IPv4 interface.  The meaning of 'address' is as in the
     constructor of *note IPv4Network: 1fe, except that arbitrary host
     addresses are always accepted.

     ‘IPv4Interface’ is a subclass of *note IPv4Address: 1fc, so it
     inherits all the attributes from that class.  In addition, the
     following attributes are available:

      -- Attribute: ip

          The address (*note IPv4Address: 1fc.) without network
          information.

               >>> interface = IPv4Interface('192.0.2.5/24')
               >>> interface.ip
               IPv4Address('192.0.2.5')

      -- Attribute: network

          The network (*note IPv4Network: 1fe.) this interface belongs
          to.

               >>> interface = IPv4Interface('192.0.2.5/24')
               >>> interface.network
               IPv4Network('192.0.2.0/24')

      -- Attribute: with_prefixlen

          A string representation of the interface with the mask in
          prefix notation.

               >>> interface = IPv4Interface('192.0.2.5/24')
               >>> interface.with_prefixlen
               '192.0.2.5/24'

      -- Attribute: with_netmask

          A string representation of the interface with the network as a
          net mask.

               >>> interface = IPv4Interface('192.0.2.5/24')
               >>> interface.with_netmask
               '192.0.2.5/255.255.255.0'

      -- Attribute: with_hostmask

          A string representation of the interface with the network as a
          host mask.

               >>> interface = IPv4Interface('192.0.2.5/24')
               >>> interface.with_hostmask
               '192.0.2.5/0.0.0.255'

 -- Class: ipaddress.IPv6Interface (address)

     Construct an IPv6 interface.  The meaning of 'address' is as in the
     constructor of *note IPv6Network: 1ff, except that arbitrary host
     addresses are always accepted.

     ‘IPv6Interface’ is a subclass of *note IPv6Address: 1fd, so it
     inherits all the attributes from that class.  In addition, the
     following attributes are available:

      -- Attribute: ip

      -- Attribute: network

      -- Attribute: with_prefixlen

      -- Attribute: with_netmask

      -- Attribute: with_hostmask

          Refer to the corresponding attribute documentation in *note
          IPv4Interface: 193f.

* Menu:

* Operators: Operators<5>.


File: python.info,  Node: Operators<5>,  Up: Interface objects

5.22.23.16 Operators
....................

Interface objects support some operators.  Unless stated otherwise,
operators can only be applied between compatible objects (i.e.  IPv4
with IPv4, IPv6 with IPv6).

* Menu:

* Logical operators: Logical operators<2>.


File: python.info,  Node: Logical operators<2>,  Up: Operators<5>

5.22.23.17 Logical operators
............................

Interface objects can be compared with the usual set of logical
operators.

For equality comparison (‘==’ and ‘!=’), both the IP address and network
must be the same for the objects to be equal.  An interface will not
compare equal to any address or network object.

For ordering (‘<’, ‘>’, etc) the rules are different.  Interface and
address objects with the same IP version can be compared, and the
address objects will always sort before the interface objects.  Two
interface objects are first compared by their networks and, if those are
the same, then by their IP addresses.


File: python.info,  Node: Other Module Level Functions,  Next: Custom Exceptions,  Prev: Interface objects,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.18 Other Module Level Functions
.......................................

The module also provides the following module level functions:

 -- Function: ipaddress.v4_int_to_packed (address)

     Represent an address as 4 packed bytes in network (big-endian)
     order.  'address' is an integer representation of an IPv4 IP
     address.  A *note ValueError: 202. is raised if the integer is
     negative or too large to be an IPv4 IP address.

          >>> ipaddress.ip_address(3221225985)
          IPv4Address('192.0.2.1')
          >>> ipaddress.v4_int_to_packed(3221225985)
          b'\xc0\x00\x02\x01'

 -- Function: ipaddress.v6_int_to_packed (address)

     Represent an address as 16 packed bytes in network (big-endian)
     order.  'address' is an integer representation of an IPv6 IP
     address.  A *note ValueError: 202. is raised if the integer is
     negative or too large to be an IPv6 IP address.

 -- Function: ipaddress.summarize_address_range (first, last)

     Return an iterator of the summarized network range given the first
     and last IP addresses.  'first' is the first *note IPv4Address:
     1fc. or *note IPv6Address: 1fd. in the range and 'last' is the last
     ‘IPv4Address’ or ‘IPv6Address’ in the range.  A *note TypeError:
     2c3. is raised if 'first' or 'last' are not IP addresses or are not
     of the same version.  A *note ValueError: 202. is raised if 'last'
     is not greater than 'first' or if 'first' address version is not 4
     or 6.

          >>> [ipaddr for ipaddr in ipaddress.summarize_address_range(
          ...    ipaddress.IPv4Address('192.0.2.0'),
          ...    ipaddress.IPv4Address('192.0.2.130'))]
          [IPv4Network('192.0.2.0/25'), IPv4Network('192.0.2.128/31'), IPv4Network('192.0.2.130/32')]

 -- Function: ipaddress.collapse_addresses (addresses)

     Return an iterator of the collapsed *note IPv4Network: 1fe. or
     *note IPv6Network: 1ff. objects.  'addresses' is an *note iterable:
     126d. of ‘IPv4Network’ or ‘IPv6Network’ objects.  A *note
     TypeError: 2c3. is raised if 'addresses' contains mixed version
     objects.

          >>> [ipaddr for ipaddr in
          ... ipaddress.collapse_addresses([ipaddress.IPv4Network('192.0.2.0/25'),
          ... ipaddress.IPv4Network('192.0.2.128/25')])]
          [IPv4Network('192.0.2.0/24')]

 -- Function: ipaddress.get_mixed_type_key (obj)

     Return a key suitable for sorting between networks and addresses.
     Address and Network objects are not sortable by default; they’re
     fundamentally different, so the expression:

          IPv4Address('192.0.2.0') <= IPv4Network('192.0.2.0/24')

     doesn’t make sense.  There are some times however, where you may
     wish to have ‘ipaddress’ sort these anyway.  If you need to do
     this, you can use this function as the 'key' argument to *note
     sorted(): bed.

     'obj' is either a network or address object.


File: python.info,  Node: Custom Exceptions,  Prev: Other Module Level Functions,  Up: ipaddress — IPv4/IPv6 manipulation library

5.22.23.19 Custom Exceptions
............................

To support more specific error reporting from class constructors, the
module defines the following exceptions:

 -- Exception: ipaddress.AddressValueError (ValueError)

     Any value error related to the address.

 -- Exception: ipaddress.NetmaskValueError (ValueError)

     Any value error related to the net mask.


File: python.info,  Node: Multimedia Services,  Next: Internationalization,  Prev: Internet Protocols and Support,  Up: The Python Standard Library

5.23 Multimedia Services
========================

The modules described in this chapter implement various algorithms or
interfaces that are mainly useful for multimedia applications.  They are
available at the discretion of the installation.  Here’s an overview:

* Menu:

* wave — Read and write WAV files::
* colorsys — Conversions between color systems::


File: python.info,  Node: wave — Read and write WAV files,  Next: colorsys — Conversions between color systems,  Up: Multimedia Services

5.23.1 ‘wave’ — Read and write WAV files
----------------------------------------

'Source code:' Lib/wave.py(1)

__________________________________________________________________

The ‘wave’ module provides a convenient interface to the Waveform Audio
“WAVE” (or “WAV”) file format.  Only uncompressed PCM encoded wave files
are supported.

Changed in version 3.12: Support for ‘WAVE_FORMAT_EXTENSIBLE’ headers
was added, provided that the extended format is
‘KSDATAFORMAT_SUBTYPE_PCM’.

The ‘wave’ module defines the following function and exception:

 -- Function: wave.open (file, mode=None)

     If 'file' is a string, open the file by that name, otherwise treat
     it as a file-like object.  'mode' can be:

     ‘'rb'’

          Read only mode.

     ‘'wb'’

          Write only mode.

     Note that it does not allow read/write WAV files.

     A 'mode' of ‘'rb'’ returns a *note Wave_read: 2b6. object, while a
     'mode' of ‘'wb'’ returns a *note Wave_write: 2b7. object.  If
     'mode' is omitted and a file-like object is passed as 'file',
     ‘file.mode’ is used as the default value for 'mode'.

     If you pass in a file-like object, the wave object will not close
     it when its ‘close()’ method is called; it is the caller’s
     responsibility to close the file object.

     The ‘open()’ function may be used in a *note with: 5d5. statement.
     When the ‘with’ block completes, the *note Wave_read.close(): 3f12.
     or *note Wave_write.close(): 3f13. method is called.

     Changed in version 3.4: Added support for unseekable files.

 -- Exception: wave.Error

     An error raised when something is impossible because it violates
     the WAV specification or hits an implementation deficiency.

* Menu:

* Wave_read Objects::
* Wave_write Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/wave.py


File: python.info,  Node: Wave_read Objects,  Next: Wave_write Objects,  Up: wave — Read and write WAV files

5.23.1.1 Wave_read Objects
..........................

 -- Class: wave.Wave_read

     Read a WAV file.

     Wave_read objects, as returned by *note open(): 955, have the
     following methods:

      -- Method: close ()

          Close the stream if it was opened by ‘wave’, and make the
          instance unusable.  This is called automatically on object
          collection.

      -- Method: getnchannels ()

          Returns number of audio channels (‘1’ for mono, ‘2’ for
          stereo).

      -- Method: getsampwidth ()

          Returns sample width in bytes.

      -- Method: getframerate ()

          Returns sampling frequency.

      -- Method: getnframes ()

          Returns number of audio frames.

      -- Method: getcomptype ()

          Returns compression type (‘'NONE'’ is the only supported
          type).

      -- Method: getcompname ()

          Human-readable version of *note getcomptype(): 3f1b.  Usually
          ‘'not compressed'’ parallels ‘'NONE'’.

      -- Method: getparams ()

          Returns a *note namedtuple(): 1ca. ‘(nchannels, sampwidth,
          framerate, nframes, comptype, compname)’, equivalent to output
          of the ‘get*()’ methods.

      -- Method: readframes (n)

          Reads and returns at most 'n' frames of audio, as a *note
          bytes: 1c2. object.

      -- Method: rewind ()

          Rewind the file pointer to the beginning of the audio stream.

     The following two methods are defined for compatibility with the
     old ‘aifc’ module, and don’t do anything interesting.

      -- Method: getmarkers ()

          Returns ‘None’.

          Deprecated since version 3.13, will be removed in version
          3.15: The method only existed for compatibility with the
          ‘aifc’ module which has been removed in Python 3.13.

      -- Method: getmark (id)

          Raise an error.

          Deprecated since version 3.13, will be removed in version
          3.15: The method only existed for compatibility with the
          ‘aifc’ module which has been removed in Python 3.13.

     The following two methods define a term “position” which is
     compatible between them, and is otherwise implementation dependent.

      -- Method: setpos (pos)

          Set the file pointer to the specified position.

      -- Method: tell ()

          Return current file pointer position.


File: python.info,  Node: Wave_write Objects,  Prev: Wave_read Objects,  Up: wave — Read and write WAV files

5.23.1.2 Wave_write Objects
...........................

 -- Class: wave.Wave_write

     Write a WAV file.

     Wave_write objects, as returned by *note open(): 955.

     For seekable output streams, the ‘wave’ header will automatically
     be updated to reflect the number of frames actually written.  For
     unseekable streams, the 'nframes' value must be accurate when the
     first frame data is written.  An accurate 'nframes' value can be
     achieved either by calling *note setnframes(): 3f22. or *note
     setparams(): 3f23. with the number of frames that will be written
     before *note close(): 3f13. is called and then using *note
     writeframesraw(): 1027. to write the frame data, or by calling
     *note writeframes(): 1028. with all of the frame data to be
     written.  In the latter case ‘writeframes()’ will calculate the
     number of frames in the data and set 'nframes' accordingly before
     writing the frame data.

     Changed in version 3.4: Added support for unseekable files.

     Wave_write objects have the following methods:

      -- Method: close ()

          Make sure 'nframes' is correct, and close the file if it was
          opened by ‘wave’.  This method is called upon object
          collection.  It will raise an exception if the output stream
          is not seekable and 'nframes' does not match the number of
          frames actually written.

      -- Method: setnchannels (n)

          Set the number of channels.

      -- Method: getnchannels ()

          Return the number of channels.

      -- Method: setsampwidth (n)

          Set the sample width to 'n' bytes.

      -- Method: getsampwidth ()

          Return the sample width in bytes.

      -- Method: setframerate (n)

          Set the frame rate to 'n'.

          Changed in version 3.2: A non-integral input to this method is
          rounded to the nearest integer.

      -- Method: getframerate ()

          Return the frame rate.

      -- Method: setnframes (n)

          Set the number of frames to 'n'.  This will be changed later
          if the number of frames actually written is different (this
          update attempt will raise an error if the output stream is not
          seekable).

      -- Method: getnframes ()

          Return the number of audio frames written so far.

      -- Method: setcomptype (type, name)

          Set the compression type and description.  At the moment, only
          compression type ‘NONE’ is supported, meaning no compression.

      -- Method: getcomptype ()

          Return the compression type (‘'NONE'’).

      -- Method: getcompname ()

          Return the human-readable compression type name.

      -- Method: setparams (tuple)

          The 'tuple' should be ‘(nchannels, sampwidth, framerate,
          nframes, comptype, compname)’, with values valid for the
          ‘set*()’ methods.  Sets all parameters.

      -- Method: getparams ()

          Return a *note namedtuple(): 1ca. ‘(nchannels, sampwidth,
          framerate, nframes, comptype, compname)’ containing the
          current output parameters.

      -- Method: tell ()

          Return current position in the file, with the same disclaimer
          for the *note Wave_read.tell(): 3f20. and *note
          Wave_read.setpos(): 3f1f. methods.

      -- Method: writeframesraw (data)

          Write audio frames, without correcting 'nframes'.

          Changed in version 3.4: Any *note bytes-like object: d55. is
          now accepted.

      -- Method: writeframes (data)

          Write audio frames and make sure 'nframes' is correct.  It
          will raise an error if the output stream is not seekable and
          the total number of frames that have been written after 'data'
          has been written does not match the previously set value for
          'nframes'.

          Changed in version 3.4: Any *note bytes-like object: d55. is
          now accepted.

          Note that it is invalid to set any parameters after calling
          ‘writeframes()’ or *note writeframesraw(): 1027, and any
          attempt to do so will raise *note wave.Error: 3f14.


File: python.info,  Node: colorsys — Conversions between color systems,  Prev: wave — Read and write WAV files,  Up: Multimedia Services

5.23.2 ‘colorsys’ — Conversions between color systems
-----------------------------------------------------

'Source code:' Lib/colorsys.py(1)

__________________________________________________________________

The ‘colorsys’ module defines bidirectional conversions of color values
between colors expressed in the RGB (Red Green Blue) color space used in
computer monitors and three other coordinate systems: YIQ, HLS (Hue
Lightness Saturation) and HSV (Hue Saturation Value).  Coordinates in
all of these color spaces are floating-point values.  In the YIQ space,
the Y coordinate is between 0 and 1, but the I and Q coordinates can be
positive or negative.  In all other spaces, the coordinates are all
between 0 and 1.

See also
........

More information about color spaces can be found at
‘https://poynton.ca/ColorFAQ.html’ and
‘https://www.cambridgeincolour.com/tutorials/color-spaces.htm’.

The ‘colorsys’ module defines the following functions:

 -- Function: colorsys.rgb_to_yiq (r, g, b)

     Convert the color from RGB coordinates to YIQ coordinates.

 -- Function: colorsys.yiq_to_rgb (y, i, q)

     Convert the color from YIQ coordinates to RGB coordinates.

 -- Function: colorsys.rgb_to_hls (r, g, b)

     Convert the color from RGB coordinates to HLS coordinates.

 -- Function: colorsys.hls_to_rgb (h, l, s)

     Convert the color from HLS coordinates to RGB coordinates.

 -- Function: colorsys.rgb_to_hsv (r, g, b)

     Convert the color from RGB coordinates to HSV coordinates.

 -- Function: colorsys.hsv_to_rgb (h, s, v)

     Convert the color from HSV coordinates to RGB coordinates.

Example:

     >>> import colorsys
     >>> colorsys.rgb_to_hsv(0.2, 0.4, 0.4)
     (0.5, 0.5, 0.4)
     >>> colorsys.hsv_to_rgb(0.5, 0.5, 0.4)
     (0.2, 0.4, 0.4)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/colorsys.py


File: python.info,  Node: Internationalization,  Next: Graphical user interfaces with Tk,  Prev: Multimedia Services,  Up: The Python Standard Library

5.24 Internationalization
=========================

The modules described in this chapter help you write software that is
independent of language and locale by providing mechanisms for selecting
a language to be used in program messages or by tailoring output to
match local conventions.

The list of modules described in this chapter is:

* Menu:

* gettext — Multilingual internationalization services::
* locale — Internationalization services::


File: python.info,  Node: gettext — Multilingual internationalization services,  Next: locale — Internationalization services,  Up: Internationalization

5.24.1 ‘gettext’ — Multilingual internationalization services
-------------------------------------------------------------

'Source code:' Lib/gettext.py(1)

__________________________________________________________________

The ‘gettext’ module provides internationalization (I18N) and
localization (L10N) services for your Python modules and applications.
It supports both the GNU ‘gettext’ message catalog API and a higher
level, class-based API that may be more appropriate for Python files.
The interface described below allows you to write your module and
application messages in one natural language, and provide a catalog of
translated messages for running under different natural languages.

Some hints on localizing your Python modules and applications are also
given.

* Menu:

* GNU gettext API::
* Class-based API::
* Internationalizing your programs and modules::
* Acknowledgements: Acknowledgements<9>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/gettext.py


File: python.info,  Node: GNU gettext API,  Next: Class-based API,  Up: gettext — Multilingual internationalization services

5.24.1.1 GNU ‘gettext’ API
..........................

The ‘gettext’ module defines the following API, which is very similar to
the GNU ‘gettext’ API. If you use this API you will affect the
translation of your entire application globally.  Often this is what you
want if your application is monolingual, with the choice of language
dependent on the locale of your user.  If you are localizing a Python
module, or if your application needs to switch languages on the fly, you
probably want to use the class-based API instead.

 -- Function: gettext.bindtextdomain (domain, localedir=None)

     Bind the 'domain' to the locale directory 'localedir'.  More
     concretely, ‘gettext’ will look for binary ‘.mo’ files for the
     given domain using the path (on Unix):
     ‘`localedir'/`language'/LC_MESSAGES/`domain'.mo’, where 'language'
     is searched for in the environment variables ‘LANGUAGE’, ‘LC_ALL’,
     ‘LC_MESSAGES’, and ‘LANG’ respectively.

     If 'localedir' is omitted or ‘None’, then the current binding for
     'domain' is returned.  (1)

 -- Function: gettext.textdomain (domain=None)

     Change or query the current global domain.  If 'domain' is ‘None’,
     then the current global domain is returned, otherwise the global
     domain is set to 'domain', which is returned.

 -- Function: gettext.gettext (message)

     Return the localized translation of 'message', based on the current
     global domain, language, and locale directory.  This function is
     usually aliased as ‘_()’ in the local namespace (see examples
     below).

 -- Function: gettext.dgettext (domain, message)

     Like *note gettext(): 14b8, but look the message up in the
     specified 'domain'.

 -- Function: gettext.ngettext (singular, plural, n)

     Like *note gettext(): 14b8, but consider plural forms.  If a
     translation is found, apply the plural formula to 'n', and return
     the resulting message (some languages have more than two plural
     forms).  If no translation is found, return 'singular' if 'n' is 1;
     return 'plural' otherwise.

     The Plural formula is taken from the catalog header.  It is a C or
     Python expression that has a free variable 'n'; the expression
     evaluates to the index of the plural in the catalog.  See the GNU
     gettext documentation(2) for the precise syntax to be used in ‘.po’
     files and the formulas for a variety of languages.

 -- Function: gettext.dngettext (domain, singular, plural, n)

     Like *note ngettext(): 3f42, but look the message up in the
     specified 'domain'.

 -- Function: gettext.pgettext (context, message)

 -- Function: gettext.dpgettext (domain, context, message)

 -- Function: gettext.npgettext (context, singular, plural, n)

 -- Function: gettext.dnpgettext (domain, context, singular, plural, n)

     Similar to the corresponding functions without the ‘p’ in the
     prefix (that is, *note gettext(): 63, *note dgettext(): 3f41, *note
     ngettext(): 3f42, *note dngettext(): 3f43.), but the translation is
     restricted to the given message 'context'.

     Added in version 3.8.

Note that GNU ‘gettext’ also defines a ‘dcgettext()’ method, but this
was deemed not useful and so it is currently unimplemented.

Here’s an example of typical usage for this API:

     import gettext
     gettext.bindtextdomain('myapplication', '/path/to/my/language/directory')
     gettext.textdomain('myapplication')
     _ = gettext.gettext
     # ...
     print(_('This is a translatable string.'))

   ---------- Footnotes ----------

   (1) The default locale directory is system dependent; for example, on
Red Hat Linux it is ‘/usr/share/locale’, but on Solaris it is
‘/usr/lib/locale’.  The ‘gettext’ module does not try to support these
system dependent defaults; instead its default is
‘`sys.base_prefix'/share/locale’ (see *note sys.base_prefix: 3f2.).  For
this reason, it is always best to call *note bindtextdomain(): 3f3f.
with an explicit absolute path at the start of your application.

   (2) https://www.gnu.org/software/gettext/manual/gettext.html


File: python.info,  Node: Class-based API,  Next: Internationalizing your programs and modules,  Prev: GNU gettext API,  Up: gettext — Multilingual internationalization services

5.24.1.2 Class-based API
........................

The class-based API of the ‘gettext’ module gives you more flexibility
and greater convenience than the GNU ‘gettext’ API. It is the
recommended way of localizing your Python applications and modules.
‘gettext’ defines a *note GNUTranslations: 3f48. class which implements
the parsing of GNU ‘.mo’ format files, and has methods for returning
strings.  Instances of this class can also install themselves in the
built-in namespace as the function ‘_()’.

 -- Function: gettext.find (domain, localedir=None, languages=None,
          all=False)

     This function implements the standard ‘.mo’ file search algorithm.
     It takes a 'domain', identical to what *note textdomain(): 3f40.
     takes.  Optional 'localedir' is as in *note bindtextdomain(): 3f3f.
     Optional 'languages' is a list of strings, where each string is a
     language code.

     If 'localedir' is not given, then the default system locale
     directory is used.  (1)  If 'languages' is not given, then the
     following environment variables are searched: ‘LANGUAGE’, ‘LC_ALL’,
     ‘LC_MESSAGES’, and ‘LANG’.  The first one returning a non-empty
     value is used for the 'languages' variable.  The environment
     variables should contain a colon separated list of languages, which
     will be split on the colon to produce the expected list of language
     code strings.

     ‘find()’ then expands and normalizes the languages, and then
     iterates through them, searching for an existing file built of
     these components:

     ‘`localedir'/`language'/LC_MESSAGES/`domain'.mo’

     The first such file name that exists is returned by ‘find()’.  If
     no such file is found, then ‘None’ is returned.  If 'all' is given,
     it returns a list of all file names, in the order in which they
     appear in the languages list or the environment variables.

 -- Function: gettext.translation (domain, localedir=None,
          languages=None, class_=None, fallback=False)

     Return a ‘*Translations’ instance based on the 'domain',
     'localedir', and 'languages', which are first passed to *note
     find(): 3f49. to get a list of the associated ‘.mo’ file paths.
     Instances with identical ‘.mo’ file names are cached.  The actual
     class instantiated is 'class_' if provided, otherwise *note
     GNUTranslations: 3f48.  The class’s constructor must take a single
     *note file object: 1208. argument.

     If multiple files are found, later files are used as fallbacks for
     earlier ones.  To allow setting the fallback, *note copy.copy():
     537. is used to clone each translation object from the cache; the
     actual instance data is still shared with the cache.

     If no ‘.mo’ file is found, this function raises *note OSError: 41a.
     if 'fallback' is false (which is the default), and returns a *note
     NullTranslations: 3f4a. instance if 'fallback' is true.

     Changed in version 3.3: *note IOError: 1090. used to be raised, it
     is now an alias of *note OSError: 41a.

     Changed in version 3.11: 'codeset' parameter is removed.

 -- Function: gettext.install (domain, localedir=None, *, names=None)

     This installs the function ‘_()’ in Python’s builtins namespace,
     based on 'domain' and 'localedir' which are passed to the function
     *note translation(): a88.

     For the 'names' parameter, please see the description of the
     translation object’s *note install(): 3f4b. method.

     As seen below, you usually mark the strings in your application
     that are candidates for translation, by wrapping them in a call to
     the ‘_()’ function, like this:

          print(_('This string will be translated.'))

     For convenience, you want the ‘_()’ function to be installed in
     Python’s builtins namespace, so it is easily accessible in all
     modules of your application.

     Changed in version 3.11: 'names' is now a keyword-only parameter.

* Menu:

* The NullTranslations class::
* The GNUTranslations class::
* Solaris message catalog support::
* The Catalog constructor::

   ---------- Footnotes ----------

   (1) See the footnote for *note bindtextdomain(): 3f3f. above.


File: python.info,  Node: The NullTranslations class,  Next: The GNUTranslations class,  Up: Class-based API

5.24.1.3 The ‘NullTranslations’ class
.....................................

Translation classes are what actually implement the translation of
original source file message strings to translated message strings.  The
base class used by all translation classes is *note NullTranslations:
3f4a.; this provides the basic interface you can use to write your own
specialized translation classes.  Here are the methods of
‘NullTranslations’:

 -- Class: gettext.NullTranslations (fp=None)

     Takes an optional *note file object: 1208. 'fp', which is ignored
     by the base class.  Initializes “protected” instance variables
     '_info' and '_charset' which are set by derived classes, as well as
     '_fallback', which is set through *note add_fallback(): 3f4d.  It
     then calls ‘self._parse(fp)’ if 'fp' is not ‘None’.

      -- Method: _parse (fp)

          No-op in the base class, this method takes file object 'fp',
          and reads the data from the file, initializing its message
          catalog.  If you have an unsupported message catalog file
          format, you should override this method to parse your format.

      -- Method: add_fallback (fallback)

          Add 'fallback' as the fallback object for the current
          translation object.  A translation object should consult the
          fallback if it cannot provide a translation for a given
          message.

      -- Method: gettext (message)

          If a fallback has been set, forward ‘gettext()’ to the
          fallback.  Otherwise, return 'message'.  Overridden in derived
          classes.

      -- Method: ngettext (singular, plural, n)

          If a fallback has been set, forward ‘ngettext()’ to the
          fallback.  Otherwise, return 'singular' if 'n' is 1; return
          'plural' otherwise.  Overridden in derived classes.

      -- Method: pgettext (context, message)

          If a fallback has been set, forward ‘pgettext()’ to the
          fallback.  Otherwise, return the translated message.
          Overridden in derived classes.

          Added in version 3.8.

      -- Method: npgettext (context, singular, plural, n)

          If a fallback has been set, forward ‘npgettext()’ to the
          fallback.  Otherwise, return the translated message.
          Overridden in derived classes.

          Added in version 3.8.

      -- Method: info ()

          Return a dictionary containing the metadata found in the
          message catalog file.

      -- Method: charset ()

          Return the encoding of the message catalog file.

      -- Method: install (names=None)

          This method installs *note gettext(): 3f4f. into the built-in
          namespace, binding it to ‘_’.

          If the 'names' parameter is given, it must be a sequence
          containing the names of functions you want to install in the
          builtins namespace in addition to ‘_()’.  Supported names are
          ‘'gettext'’, ‘'ngettext'’, ‘'pgettext'’, and ‘'npgettext'’.

          Note that this is only one way, albeit the most convenient
          way, to make the ‘_()’ function available to your application.
          Because it affects the entire application globally, and
          specifically the built-in namespace, localized modules should
          never install ‘_()’.  Instead, they should use this code to
          make ‘_()’ available to their module:

               import gettext
               t = gettext.translation('mymodule', ...)
               _ = t.gettext

          This puts ‘_()’ only in the module’s global namespace and so
          only affects calls within this module.

          Changed in version 3.8: Added ‘'pgettext'’ and ‘'npgettext'’.


File: python.info,  Node: The GNUTranslations class,  Next: Solaris message catalog support,  Prev: The NullTranslations class,  Up: Class-based API

5.24.1.4 The ‘GNUTranslations’ class
....................................

The ‘gettext’ module provides one additional class derived from *note
NullTranslations: 3f4a.: *note GNUTranslations: 3f48.  This class
overrides ‘_parse()’ to enable reading GNU ‘gettext’ format ‘.mo’ files
in both big-endian and little-endian format.

*note GNUTranslations: 3f48. parses optional metadata out of the
translation catalog.  It is convention with GNU ‘gettext’ to include
metadata as the translation for the empty string.  This metadata is in
RFC 822(1)-style ‘key: value’ pairs, and should contain the
‘Project-Id-Version’ key.  If the key ‘Content-Type’ is found, then the
‘charset’ property is used to initialize the “protected” ‘_charset’
instance variable, defaulting to ‘None’ if not found.  If the charset
encoding is specified, then all message ids and message strings read
from the catalog are converted to Unicode using this encoding, else
ASCII is assumed.

Since message ids are read as Unicode strings too, all ‘*gettext()’
methods will assume message ids as Unicode strings, not byte strings.

The entire set of key/value pairs are placed into a dictionary and set
as the “protected” ‘_info’ instance variable.

If the ‘.mo’ file’s magic number is invalid, the major version number is
unexpected, or if other problems occur while reading the file,
instantiating a *note GNUTranslations: 3f48. class can raise *note
OSError: 41a.

 -- Class: gettext.GNUTranslations

     The following methods are overridden from the base class
     implementation:

      -- Method: gettext (message)

          Look up the 'message' id in the catalog and return the
          corresponding message string, as a Unicode string.  If there
          is no entry in the catalog for the 'message' id, and a
          fallback has been set, the look up is forwarded to the
          fallback’s *note gettext(): 3f4f. method.  Otherwise, the
          'message' id is returned.

      -- Method: ngettext (singular, plural, n)

          Do a plural-forms lookup of a message id.  'singular' is used
          as the message id for purposes of lookup in the catalog, while
          'n' is used to determine which plural form to use.  The
          returned message string is a Unicode string.

          If the message id is not found in the catalog, and a fallback
          is specified, the request is forwarded to the fallback’s *note
          ngettext(): 3f50. method.  Otherwise, when 'n' is 1 'singular'
          is returned, and 'plural' is returned in all other cases.

          Here is an example:

               n = len(os.listdir('.'))
               cat = GNUTranslations(somefile)
               message = cat.ngettext(
                   'There is %(num)d file in this directory',
                   'There are %(num)d files in this directory',
                   n) % {'num': n}

      -- Method: pgettext (context, message)

          Look up the 'context' and 'message' id in the catalog and
          return the corresponding message string, as a Unicode string.
          If there is no entry in the catalog for the 'message' id and
          'context', and a fallback has been set, the look up is
          forwarded to the fallback’s ‘pgettext()’ method.  Otherwise,
          the 'message' id is returned.

          Added in version 3.8.

      -- Method: npgettext (context, singular, plural, n)

          Do a plural-forms lookup of a message id.  'singular' is used
          as the message id for purposes of lookup in the catalog, while
          'n' is used to determine which plural form to use.

          If the message id for 'context' is not found in the catalog,
          and a fallback is specified, the request is forwarded to the
          fallback’s ‘npgettext()’ method.  Otherwise, when 'n' is 1
          'singular' is returned, and 'plural' is returned in all other
          cases.

          Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc822.html


File: python.info,  Node: Solaris message catalog support,  Next: The Catalog constructor,  Prev: The GNUTranslations class,  Up: Class-based API

5.24.1.5 Solaris message catalog support
........................................

The Solaris operating system defines its own binary ‘.mo’ file format,
but since no documentation can be found on this format, it is not
supported at this time.


File: python.info,  Node: The Catalog constructor,  Prev: Solaris message catalog support,  Up: Class-based API

5.24.1.6 The Catalog constructor
................................

GNOME uses a version of the ‘gettext’ module by James Henstridge, but
this version has a slightly different API. Its documented usage was:

     import gettext
     cat = gettext.Catalog(domain, localedir)
     _ = cat.gettext
     print(_('hello world'))

For compatibility with this older module, the function ‘Catalog()’ is an
alias for the *note translation(): a88. function described above.

One difference between this module and Henstridge’s: his catalog objects
supported access through a mapping API, but this appears to be unused
and so is not currently supported.


File: python.info,  Node: Internationalizing your programs and modules,  Next: Acknowledgements<9>,  Prev: Class-based API,  Up: gettext — Multilingual internationalization services

5.24.1.7 Internationalizing your programs and modules
.....................................................

Internationalization (I18N) refers to the operation by which a program
is made aware of multiple languages.  Localization (L10N) refers to the
adaptation of your program, once internationalized, to the local
language and cultural habits.  In order to provide multilingual messages
for your Python programs, you need to take the following steps:

  1. prepare your program or module by specially marking translatable
     strings

  2. run a suite of tools over your marked files to generate raw
     messages catalogs

  3. create language-specific translations of the message catalogs

  4. use the ‘gettext’ module so that message strings are properly
     translated

In order to prepare your code for I18N, you need to look at all the
strings in your files.  Any string that needs to be translated should be
marked by wrapping it in ‘_('...')’ — that is, a call to the function
*note _: 63.  For example:

     filename = 'mylog.txt'
     message = _('writing a log message')
     with open(filename, 'w') as fp:
         fp.write(message)

In this example, the string ‘'writing a log message'’ is marked as a
candidate for translation, while the strings ‘'mylog.txt'’ and ‘'w'’ are
not.

There are a few tools to extract the strings meant for translation.  The
original GNU ‘gettext’ only supported C or C++ source code but its
extended version ‘xgettext’ scans code written in a number of languages,
including Python, to find strings marked as translatable.  Babel(1) is a
Python internationalization library that includes a ‘pybabel’ script to
extract and compile message catalogs.  François Pinard’s program called
‘xpot’ does a similar job and is available as part of his po-utils
package(2).

(Python also includes pure-Python versions of these programs, called
‘pygettext.py’ and ‘msgfmt.py’; some Python distributions will install
them for you.  ‘pygettext.py’ is similar to ‘xgettext’, but only
understands Python source code and cannot handle other programming
languages such as C or C++.  ‘pygettext.py’ supports a command-line
interface similar to ‘xgettext’; for details on its use, run
‘pygettext.py --help’.  ‘msgfmt.py’ is binary compatible with GNU
‘msgfmt’.  With these two programs, you may not need the GNU ‘gettext’
package to internationalize your Python applications.)

‘xgettext’, ‘pygettext’, and similar tools generate ‘.po’ files that are
message catalogs.  They are structured human-readable files that contain
every marked string in the source code, along with a placeholder for the
translated versions of these strings.

Copies of these ‘.po’ files are then handed over to the individual human
translators who write translations for every supported natural language.
They send back the completed language-specific versions as a
‘<language-name>.po’ file that’s compiled into a machine-readable ‘.mo’
binary catalog file using the ‘msgfmt’ program.  The ‘.mo’ files are
used by the ‘gettext’ module for the actual translation processing at
run-time.

How you use the ‘gettext’ module in your code depends on whether you are
internationalizing a single module or your entire application.  The next
two sections will discuss each case.

* Menu:

* Localizing your module::
* Localizing your application::
* Changing languages on the fly::
* Deferred translations::

   ---------- Footnotes ----------

   (1) https://babel.pocoo.org/

   (2) https://github.com/pinard/po-utils


File: python.info,  Node: Localizing your module,  Next: Localizing your application,  Up: Internationalizing your programs and modules

5.24.1.8 Localizing your module
...............................

If you are localizing your module, you must take care not to make global
changes, e.g.  to the built-in namespace.  You should not use the GNU
‘gettext’ API but instead the class-based API.

Let’s say your module is called “spam” and the module’s various natural
language translation ‘.mo’ files reside in ‘/usr/share/locale’ in GNU
‘gettext’ format.  Here’s what you would put at the top of your module:

     import gettext
     t = gettext.translation('spam', '/usr/share/locale')
     _ = t.gettext


File: python.info,  Node: Localizing your application,  Next: Changing languages on the fly,  Prev: Localizing your module,  Up: Internationalizing your programs and modules

5.24.1.9 Localizing your application
....................................

If you are localizing your application, you can install the ‘_()’
function globally into the built-in namespace, usually in the main
driver file of your application.  This will let all your
application-specific files just use ‘_('...')’ without having to
explicitly install it in each file.

In the simple case then, you need only add the following bit of code to
the main driver file of your application:

     import gettext
     gettext.install('myapplication')

If you need to set the locale directory, you can pass it into the *note
install(): a89. function:

     import gettext
     gettext.install('myapplication', '/usr/share/locale')


File: python.info,  Node: Changing languages on the fly,  Next: Deferred translations,  Prev: Localizing your application,  Up: Internationalizing your programs and modules

5.24.1.10 Changing languages on the fly
.......................................

If your program needs to support many languages at the same time, you
may want to create multiple translation instances and then switch
between them explicitly, like so:

     import gettext

     lang1 = gettext.translation('myapplication', languages=['en'])
     lang2 = gettext.translation('myapplication', languages=['fr'])
     lang3 = gettext.translation('myapplication', languages=['de'])

     # start by using language1
     lang1.install()

     # ... time goes by, user selects language 2
     lang2.install()

     # ... more time goes by, user selects language 3
     lang3.install()


File: python.info,  Node: Deferred translations,  Prev: Changing languages on the fly,  Up: Internationalizing your programs and modules

5.24.1.11 Deferred translations
...............................

In most coding situations, strings are translated where they are coded.
Occasionally however, you need to mark strings for translation, but
defer actual translation until later.  A classic example is:

     animals = ['mollusk',
                'albatross',
                'rat',
                'penguin',
                'python', ]
     # ...
     for a in animals:
         print(a)

Here, you want to mark the strings in the ‘animals’ list as being
translatable, but you don’t actually want to translate them until they
are printed.

Here is one way you can handle this situation:

     def _(message): return message

     animals = [_('mollusk'),
                _('albatross'),
                _('rat'),
                _('penguin'),
                _('python'), ]

     del _

     # ...
     for a in animals:
         print(_(a))

This works because the dummy definition of ‘_()’ simply returns the
string unchanged.  And this dummy definition will temporarily override
any definition of ‘_()’ in the built-in namespace (until the *note del:
18c2. command).  Take care, though if you have a previous definition of
‘_()’ in the local namespace.

Note that the second use of ‘_()’ will not identify “a” as being
translatable to the ‘gettext’ program, because the parameter is not a
string literal.

Another way to handle this is with the following example:

     def N_(message): return message

     animals = [N_('mollusk'),
                N_('albatross'),
                N_('rat'),
                N_('penguin'),
                N_('python'), ]

     # ...
     for a in animals:
         print(_(a))

In this case, you are marking translatable strings with the function
‘N_()’, which won’t conflict with any definition of ‘_()’.  However, you
will need to teach your message extraction program to look for
translatable strings marked with ‘N_()’.  ‘xgettext’, ‘pygettext’,
‘pybabel extract’, and ‘xpot’ all support this through the use of the
‘-k’ command-line switch.  The choice of ‘N_()’ here is totally
arbitrary; it could have just as easily been
‘MarkThisStringForTranslation()’.


File: python.info,  Node: Acknowledgements<9>,  Prev: Internationalizing your programs and modules,  Up: gettext — Multilingual internationalization services

5.24.1.12 Acknowledgements
..........................

The following people contributed code, feedback, design suggestions,
previous implementations, and valuable experience to the creation of
this module:

   * Peter Funk

   * James Henstridge

   * Juan David Ibáñez Palomar

   * Marc-André Lemburg

   * Martin von Löwis

   * François Pinard

   * Barry Warsaw

   * Gustavo Niemeyer


File: python.info,  Node: locale — Internationalization services,  Prev: gettext — Multilingual internationalization services,  Up: Internationalization

5.24.2 ‘locale’ — Internationalization services
-----------------------------------------------

'Source code:' Lib/locale.py(1)

__________________________________________________________________

The ‘locale’ module opens access to the POSIX locale database and
functionality.  The POSIX locale mechanism allows programmers to deal
with certain cultural issues in an application, without requiring the
programmer to know all the specifics of each country where the software
is executed.

The ‘locale’ module is implemented on top of the ‘_locale’ module, which
in turn uses an ANSI C locale implementation if available.

The ‘locale’ module defines the following exception and functions:

 -- Exception: locale.Error

     Exception raised when the locale passed to *note setlocale(): 2db.
     is not recognized.

 -- Function: locale.setlocale (category, locale=None)

     If 'locale' is given and not ‘None’, ‘setlocale()’ modifies the
     locale setting for the 'category'.  The available categories are
     listed in the data description below.  'locale' may be a *note
     string: 3f66, or a pair, language code and encoding.  An empty
     string specifies the user’s default settings.  If the modification
     of the locale fails, the exception *note Error: 3f65. is raised.
     If successful, the new locale setting is returned.

     If 'locale' is a pair, it is converted to a locale name using the
     locale aliasing engine.  The language code has the same format as a
     *note locale name: 3f66, but without encoding and ‘@’-modifier.
     The language code and encoding can be ‘None’.

     If 'locale' is omitted or ‘None’, the current setting for
     'category' is returned.

     Example:

          >>> import locale
          >>> loc = locale.setlocale(locale.LC_ALL)  # get current locale
          # use German locale; name and availability varies with platform
          >>> locale.setlocale(locale.LC_ALL, 'de_DE.UTF-8')
          >>> locale.strcoll('f\xe4n', 'foo')  # compare a string containing an umlaut
          >>> locale.setlocale(locale.LC_ALL, '')   # use user's preferred locale
          >>> locale.setlocale(locale.LC_ALL, 'C')  # use default (C) locale
          >>> locale.setlocale(locale.LC_ALL, loc)  # restore saved locale

     ‘setlocale()’ is not thread-safe on most systems.  Applications
     typically start with a call of:

          import locale
          locale.setlocale(locale.LC_ALL, '')

     This sets the locale for all categories to the user’s default
     setting (typically specified in the ‘LANG’ environment variable).
     If the locale is not changed thereafter, using multithreading
     should not cause problems.

 -- Function: locale.localeconv ()

     Returns the database of the local conventions as a dictionary.
     This dictionary has the following strings as keys:

     Category                   Key                                       Meaning
                                                                          
     ----------------------------------------------------------------------------------------------------------
                                                                          
     *note LC_NUMERIC: 3f67.    ‘'decimal_point'’                         Decimal point character.
                                                                          
                                                                          
                                ‘'grouping'’                              Sequence of numbers specifying
                                                                          which relative positions the
                                                                          ‘'thousands_sep'’ is expected.  If
                                                                          the sequence is terminated with
                                                                          *note CHAR_MAX: 3f68, no further
                                                                          grouping is performed.  If the
                                                                          sequence terminates with a ‘0’,
                                                                          the last group size is repeatedly
                                                                          used.
                                                                          
                                                                          
                                ‘'thousands_sep'’                         Character used between groups.
                                                                          
                                                                          
     *note LC_MONETARY: 3f69.   ‘'int_curr_symbol'’                       International currency symbol.
                                                                          
                                                                          
                                ‘'currency_symbol'’                       Local currency symbol.
                                                                          
                                                                          
                                ‘'p_cs_precedes/n_cs_precedes'’           Whether the currency symbol
                                                                          precedes the value (for positive
                                                                          resp.  negative values).
                                                                          
                                                                          
                                ‘'p_sep_by_space/n_sep_by_space'’         Whether the currency symbol is
                                                                          separated from the value by a
                                                                          space (for positive resp.
                                                                          negative values).
                                                                          
                                                                          
                                ‘'mon_decimal_point'’                     Decimal point used for monetary
                                                                          values.
                                                                          
                                                                          
                                ‘'frac_digits'’                           Number of fractional digits used
                                                                          in local formatting of monetary
                                                                          values.
                                                                          
                                                                          
                                ‘'int_frac_digits'’                       Number of fractional digits used
                                                                          in international formatting of
                                                                          monetary values.
                                                                          
                                                                          
                                ‘'mon_thousands_sep'’                     Group separator used for monetary
                                                                          values.
                                                                          
                                                                          
                                ‘'mon_grouping'’                          Equivalent to ‘'grouping'’, used
                                                                          for monetary values.
                                                                          
                                                                          
                                ‘'positive_sign'’                         Symbol used to annotate a positive
                                                                          monetary value.
                                                                          
                                                                          
                                ‘'negative_sign'’                         Symbol used to annotate a negative
                                                                          monetary value.
                                                                          
                                                                          
                                ‘'p_sign_posn/n_sign_posn'’               The position of the sign (for
                                                                          positive resp.  negative values),
                                                                          see below.
                                                                          

     All numeric values can be set to *note CHAR_MAX: 3f68. to indicate
     that there is no value specified in this locale.

     The possible values for ‘'p_sign_posn'’ and ‘'n_sign_posn'’ are
     given below.

     Value              Explanation
                        
     -----------------------------------------------------------------
                        
     ‘0’                Currency and value are surrounded by
                        parentheses.
                        
                        
     ‘1’                The sign should precede the value and
                        currency symbol.
                        
                        
     ‘2’                The sign should follow the value and
                        currency symbol.
                        
                        
     ‘3’                The sign should immediately precede the
                        value.
                        
                        
     ‘4’                The sign should immediately follow the
                        value.
                        
                        
     ‘CHAR_MAX’         Nothing is specified in this locale.
                        

     The function temporarily sets the ‘LC_CTYPE’ locale to the
     ‘LC_NUMERIC’ locale or the ‘LC_MONETARY’ locale if locales are
     different and numeric or monetary strings are non-ASCII. This
     temporary change affects other threads.

     Changed in version 3.7: The function now temporarily sets the
     ‘LC_CTYPE’ locale to the ‘LC_NUMERIC’ locale in some cases.

 -- Function: locale.nl_langinfo (option)

     Return some locale-specific information as a string.  This function
     is not available on all systems, and the set of possible options
     might also vary across platforms.  The possible argument values are
     numbers, for which symbolic constants are available in the locale
     module.

     The ‘nl_langinfo()’ function accepts one of the following keys.
     Most descriptions are taken from the corresponding description in
     the GNU C library.

      -- Data: locale.CODESET

          Get a string with the name of the character encoding used in
          the selected locale.

      -- Data: locale.D_T_FMT

          Get a string that can be used as a format string for *note
          time.strftime(): 122e. to represent date and time in a
          locale-specific way.

      -- Data: locale.D_FMT

          Get a string that can be used as a format string for *note
          time.strftime(): 122e. to represent a date in a
          locale-specific way.

      -- Data: locale.T_FMT

          Get a string that can be used as a format string for *note
          time.strftime(): 122e. to represent a time in a
          locale-specific way.

      -- Data: locale.T_FMT_AMPM

          Get a format string for *note time.strftime(): 122e. to
          represent time in the am/pm format.

      -- Data: locale.DAY_1
      -- Data: locale.DAY_2
      -- Data: locale.DAY_3
      -- Data: locale.DAY_4
      -- Data: locale.DAY_5
      -- Data: locale.DAY_6
      -- Data: locale.DAY_7

          Get the name of the n-th day of the week.

               Note: This follows the US convention of *note DAY_1:
               3f70. being Sunday, not the international convention (ISO
               8601) that Monday is the first day of the week.

      -- Data: locale.ABDAY_1
      -- Data: locale.ABDAY_2
      -- Data: locale.ABDAY_3
      -- Data: locale.ABDAY_4
      -- Data: locale.ABDAY_5
      -- Data: locale.ABDAY_6
      -- Data: locale.ABDAY_7

          Get the abbreviated name of the n-th day of the week.

      -- Data: locale.MON_1
      -- Data: locale.MON_2
      -- Data: locale.MON_3
      -- Data: locale.MON_4
      -- Data: locale.MON_5
      -- Data: locale.MON_6
      -- Data: locale.MON_7
      -- Data: locale.MON_8
      -- Data: locale.MON_9
      -- Data: locale.MON_10
      -- Data: locale.MON_11
      -- Data: locale.MON_12

          Get the name of the n-th month.

      -- Data: locale.ABMON_1
      -- Data: locale.ABMON_2
      -- Data: locale.ABMON_3
      -- Data: locale.ABMON_4
      -- Data: locale.ABMON_5
      -- Data: locale.ABMON_6
      -- Data: locale.ABMON_7
      -- Data: locale.ABMON_8
      -- Data: locale.ABMON_9
      -- Data: locale.ABMON_10
      -- Data: locale.ABMON_11
      -- Data: locale.ABMON_12

          Get the abbreviated name of the n-th month.

      -- Data: locale.RADIXCHAR

          Get the radix character (decimal dot, decimal comma, etc.).

      -- Data: locale.THOUSEP

          Get the separator character for thousands (groups of three
          digits).

      -- Data: locale.YESEXPR

          Get a regular expression that can be used with the regex
          function to recognize a positive response to a yes/no
          question.

      -- Data: locale.NOEXPR

          Get a regular expression that can be used with the ‘regex(3)’
          function to recognize a negative response to a yes/no
          question.

               Note: The regular expressions for *note YESEXPR: 3f98.
               and *note NOEXPR: 3f99. use syntax suitable for the
               ‘regex’ function from the C library, which might differ
               from the syntax used in *note re: b9.

      -- Data: locale.CRNCYSTR

          Get the currency symbol, preceded by “-” if the symbol should
          appear before the value, “+” if the symbol should appear after
          the value, or “.” if the symbol should replace the radix
          character.

      -- Data: locale.ERA

          Get a string which describes how years are counted and
          displayed for each era in a locale.

          Most locales do not define this value.  An example of a locale
          which does define this value is the Japanese one.  In Japan,
          the traditional representation of dates includes the name of
          the era corresponding to the then-emperor’s reign.

          Normally it should not be necessary to use this value
          directly.  Specifying the ‘E’ modifier in their format strings
          causes the *note time.strftime(): 122e. function to use this
          information.  The format of the returned string is specified
          in 'The Open Group Base Specifications Issue 8', paragraph
          7.3.5.2 LC_TIME C-Language Access(2).

      -- Data: locale.ERA_D_T_FMT

          Get a format string for *note time.strftime(): 122e. to
          represent date and time in a locale-specific era-based way.

      -- Data: locale.ERA_D_FMT

          Get a format string for *note time.strftime(): 122e. to
          represent a date in a locale-specific era-based way.

      -- Data: locale.ERA_T_FMT

          Get a format string for *note time.strftime(): 122e. to
          represent a time in a locale-specific era-based way.

      -- Data: locale.ALT_DIGITS

          Get a string consisting of up to 100 semicolon-separated
          symbols used to represent the values 0 to 99 in a
          locale-specific way.  In most locales this is an empty string.

 -- Function: locale.getdefaultlocale ([envvars])

     Tries to determine the default locale settings and returns them as
     a tuple of the form ‘(language code, encoding)’.

     According to POSIX, a program which has not called
     ‘setlocale(LC_ALL, '')’ runs using the portable ‘'C'’ locale.
     Calling ‘setlocale(LC_ALL, '')’ lets it use the default locale as
     defined by the ‘LANG’ variable.  Since we do not want to interfere
     with the current locale setting we thus emulate the behavior in the
     way described above.

     To maintain compatibility with other platforms, not only the ‘LANG’
     variable is tested, but a list of variables given as envvars
     parameter.  The first found to be defined will be used.  'envvars'
     defaults to the search path used in GNU gettext; it must always
     contain the variable name ‘'LANG'’.  The GNU gettext search path
     contains ‘'LC_ALL'’, ‘'LC_CTYPE'’, ‘'LANG'’ and ‘'LANGUAGE'’, in
     that order.

     The language code has the same format as a *note locale name: 3f66,
     but without encoding and ‘@’-modifier.  The language code and
     encoding may be ‘None’ if their values cannot be determined.  The
     “C” locale is represented as ‘(None, None)’.

     Deprecated since version 3.11, will be removed in version 3.15.

 -- Function: locale.getlocale (category=LC_CTYPE)

     Returns the current setting for the given locale category as a
     tuple containing the language code and encoding.  'category' may be
     one of the ‘LC_*’ values except *note LC_ALL: 3fa0.  It defaults to
     *note LC_CTYPE: 3fa1.

     The language code has the same format as a *note locale name: 3f66,
     but without encoding and ‘@’-modifier.  The language code and
     encoding may be ‘None’ if their values cannot be determined.  The
     “C” locale is represented as ‘(None, None)’.

 -- Function: locale.getpreferredencoding (do_setlocale=True)

     Return the *note locale encoding: 242. used for text data,
     according to user preferences.  User preferences are expressed
     differently on different systems, and might not be available
     programmatically on some systems, so this function only returns a
     guess.

     On some systems, it is necessary to invoke *note setlocale(): 2db.
     to obtain the user preferences, so this function is not
     thread-safe.  If invoking setlocale is not necessary or desired,
     'do_setlocale' should be set to ‘False’.

     On Android or if the *note Python UTF-8 Mode: 659. is enabled,
     always return ‘'utf-8'’, the *note locale encoding: 242. and the
     'do_setlocale' argument are ignored.

     The *note Python preinitialization: 3fa2. configures the LC_CTYPE
     locale.  See also the *note filesystem encoding and error handler:
     53e.

     Changed in version 3.7: The function now always returns ‘"utf-8"’
     on Android or if the *note Python UTF-8 Mode: 659. is enabled.

 -- Function: locale.getencoding ()

     Get the current *note locale encoding: 242.:

        * On Android and VxWorks, return ‘"utf-8"’.

        * On Unix, return the encoding of the current *note LC_CTYPE:
          3fa1. locale.  Return ‘"utf-8"’ if ‘nl_langinfo(CODESET)’
          returns an empty string: for example, if the current LC_CTYPE
          locale is not supported.

        * On Windows, return the ANSI code page.

     The *note Python preinitialization: 3fa2. configures the LC_CTYPE
     locale.  See also the *note filesystem encoding and error handler:
     53e.

     This function is similar to *note getpreferredencoding(False): 53d.
     except this function ignores the *note Python UTF-8 Mode: 659.

     Added in version 3.11.

 -- Function: locale.normalize (localename)

     Returns a normalized locale code for the given locale name.  The
     returned locale code is formatted for use with *note setlocale():
     2db.  If normalization fails, the original name is returned
     unchanged.

     If the given encoding is not known, the function defaults to the
     default encoding for the locale code just like *note setlocale():
     2db.

 -- Function: locale.strcoll (string1, string2)

     Compares two strings according to the current *note LC_COLLATE:
     3fa5. setting.  As any other compare function, returns a negative,
     or a positive value, or ‘0’, depending on whether 'string1'
     collates before or after 'string2' or is equal to it.

 -- Function: locale.strxfrm (string)

     Transforms a string to one that can be used in locale-aware
     comparisons.  For example, ‘strxfrm(s1) < strxfrm(s2)’ is
     equivalent to ‘strcoll(s1, s2) < 0’.  This function can be used
     when the same string is compared repeatedly, e.g.  when collating a
     sequence of strings.

 -- Function: locale.format_string (format, val, grouping=False,
          monetary=False)

     Formats a number 'val' according to the current *note LC_NUMERIC:
     3f67. setting.  The format follows the conventions of the ‘%’
     operator.  For floating-point values, the decimal point is modified
     if appropriate.  If 'grouping' is ‘True’, also takes the grouping
     into account.

     If 'monetary' is true, the conversion uses monetary thousands
     separator and grouping strings.

     Processes formatting specifiers as in ‘format % val’, but takes the
     current locale settings into account.

     Changed in version 3.7: The 'monetary' keyword parameter was added.

 -- Function: locale.currency (val, symbol=True, grouping=False,
          international=False)

     Formats a number 'val' according to the current *note LC_MONETARY:
     3f69. settings.

     The returned string includes the currency symbol if 'symbol' is
     true, which is the default.  If 'grouping' is ‘True’ (which is not
     the default), grouping is done with the value.  If 'international'
     is ‘True’ (which is not the default), the international currency
     symbol is used.

          Note: This function will not work with the ‘C’ locale, so you
          have to set a locale via *note setlocale(): 2db. first.

 -- Function: locale.str (float)

     Formats a floating-point number using the same format as the
     built-in function ‘str(float)’, but takes the decimal point into
     account.

 -- Function: locale.delocalize (string)

     Converts a string into a normalized number string, following the
     *note LC_NUMERIC: 3f67. settings.

     Added in version 3.5.

 -- Function: locale.localize (string, grouping=False, monetary=False)

     Converts a normalized number string into a formatted string
     following the *note LC_NUMERIC: 3f67. settings.

     Added in version 3.10.

 -- Function: locale.atof (string, func=float)

     Converts a string to a number, following the *note LC_NUMERIC:
     3f67. settings, by calling 'func' on the result of calling *note
     delocalize(): e58. on 'string'.

 -- Function: locale.atoi (string)

     Converts a string to an integer, following the *note LC_NUMERIC:
     3f67. conventions.

 -- Data: locale.LC_CTYPE

     Locale category for the character type functions.  Most
     importantly, this category defines the text encoding, i.e.  how
     bytes are interpreted as Unicode codepoints.  See PEP 538(3) and
     PEP 540(4) for how this variable might be automatically coerced to
     ‘C.UTF-8’ to avoid issues created by invalid settings in containers
     or incompatible settings passed over remote SSH connections.

     Python doesn’t internally use locale-dependent character
     transformation functions from ‘ctype.h’.  Instead, ‘pyctype.h’
     provides locale-independent equivalents like *note Py_TOLOWER:
     13a4.

 -- Data: locale.LC_COLLATE

     Locale category for sorting strings.  The functions *note
     strcoll(): 3fa4. and *note strxfrm(): 1614. of the ‘locale’ module
     are affected.

 -- Data: locale.LC_TIME

     Locale category for the formatting of time.  The function *note
     time.strftime(): 122e. follows these conventions.

 -- Data: locale.LC_MONETARY

     Locale category for formatting of monetary values.  The available
     options are available from the *note localeconv(): c1e. function.

 -- Data: locale.LC_MESSAGES

     Locale category for message display.  Python currently does not
     support application specific locale-aware messages.  Messages
     displayed by the operating system, like those returned by *note
     os.strerror(): 2d21. might be affected by this category.

     This value may not be available on operating systems not conforming
     to the POSIX standard, most notably Windows.

 -- Data: locale.LC_NUMERIC

     Locale category for formatting numbers.  The functions *note
     format_string(): 522, *note atoi(): 3faa, *note atof(): 3fa9. and
     *note str(): 3fa7. of the ‘locale’ module are affected by that
     category.  All other numeric formatting operations are not
     affected.

 -- Data: locale.LC_ALL

     Combination of all locale settings.  If this flag is used when the
     locale is changed, setting the locale for all categories is
     attempted.  If that fails for any category, no category is changed
     at all.  When the locale is retrieved using this flag, a string
     indicating the setting for all categories is returned.  This string
     can be later used to restore the settings.

 -- Data: locale.CHAR_MAX

     This is a symbolic constant used for different values returned by
     *note localeconv(): c1e.

* Menu:

* Background, details, hints, tips and caveats: Background details hints tips and caveats.
* Locale names::
* For extension writers and programs that embed Python::
* Access to message catalogs::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/locale.py

   (2) 
https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap07.html#tag_07_03_05_02

   (3) https://peps.python.org/pep-0538/

   (4) https://peps.python.org/pep-0540/


File: python.info,  Node: Background details hints tips and caveats,  Next: Locale names,  Up: locale — Internationalization services

5.24.2.1 Background, details, hints, tips and caveats
.....................................................

The C standard defines the locale as a program-wide property that may be
relatively expensive to change.  On top of that, some implementations
are broken in such a way that frequent locale changes may cause core
dumps.  This makes the locale somewhat painful to use correctly.

Initially, when a program is started, the locale is the ‘C’ locale, no
matter what the user’s preferred locale is.  There is one exception: the
*note LC_CTYPE: 3fa1. category is changed at startup to set the current
locale encoding to the user’s preferred locale encoding.  The program
must explicitly say that it wants the user’s preferred locale settings
for other categories by calling ‘setlocale(LC_ALL, '')’.

It is generally a bad idea to call *note setlocale(): 2db. in some
library routine, since as a side effect it affects the entire program.
Saving and restoring it is almost as bad: it is expensive and affects
other threads that happen to run before the settings have been restored.

If, when coding a module for general use, you need a locale independent
version of an operation that is affected by the locale (such as certain
formats used with *note time.strftime(): 122e.), you will have to find a
way to do it without using the standard library routine.  Even better is
convincing yourself that using locale settings is okay.  Only as a last
resort should you document that your module is not compatible with
non-‘C’ locale settings.

The only way to perform numeric operations according to the locale is to
use the special functions defined by this module: *note atof(): 3fa9,
*note atoi(): 3faa, *note format_string(): 522, *note str(): 3fa7.

There is no way to perform case conversions and character
classifications according to the locale.  For (Unicode) text strings
these are done according to the character value only, while for byte
strings, the conversions and classifications are done according to the
ASCII value of the byte, and bytes whose high bit is set (i.e.,
non-ASCII bytes) are never converted or considered part of a character
class such as letter or whitespace.


File: python.info,  Node: Locale names,  Next: For extension writers and programs that embed Python,  Prev: Background details hints tips and caveats,  Up: locale — Internationalization services

5.24.2.2 Locale names
.....................

The format of the locale name is platform dependent, and the set of
supported locales can depend on the system configuration.

On Posix platforms, it usually has the format (1):

          language ["_" territory] ["." charset] ["@" modifier]

where 'language' is a two- or three-letter language code from ISO
639(2), 'territory' is a two-letter country or region code from ISO
3166(3), 'charset' is a locale encoding, and 'modifier' is a script
name, a language subtag, a sort order identifier, or other locale
modifier (for example, “latin”, “valencia”, “stroke” and “euro”).

On Windows, several formats are supported.  (4)  (5)  A subset of IETF
BCP 47(6) tags:

          language ["-" script] ["-" territory] ["." charset]
          language ["-" script] "-" territory "-" modifier

where 'language' and 'territory' have the same meaning as in Posix,
'script' is a four-letter script code from ISO 15924(7), and 'modifier'
is a language subtag, a sort order identifier or custom modifier (for
example, “valencia”, “stroke” or “x-python”).  Both hyphen (‘'-'’) and
underscore (‘'_'’) separators are supported.  Only UTF-8 encoding is
allowed for BCP 47 tags.

Windows also supports locale names in the format:

          language ["_" territory] ["." charset]

where 'language' and 'territory' are full names, such as “English” and
“United States”, and 'charset' is either a code page number (for
example, “1252”) or UTF-8.  Only the underscore separator is supported
in this format.

The “C” locale is supported on all platforms.

   ---------- Footnotes ----------

   (1) IEEE Std 1003.1-2024; 8.2 Internationalization Variables
(https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap08.html#tag_08_02)

   (2) https://www.iso.org/iso-639-language-code

   (3) https://www.iso.org/iso-3166-country-codes.html

   (4) UCRT Locale names, Languages, and Country/Region strings
(https://learn.microsoft.com/en-us/cpp/c-runtime-library/locale-names-languages-and-country-region-strings)

   (5) Locale Names
(https://learn.microsoft.com/en-us/windows/win32/intl/locale-names)

   (6) https://www.rfc-editor.org/info/bcp47

   (7) https://www.unicode.org/iso15924/


File: python.info,  Node: For extension writers and programs that embed Python,  Next: Access to message catalogs,  Prev: Locale names,  Up: locale — Internationalization services

5.24.2.3 For extension writers and programs that embed Python
.............................................................

Extension modules should never call *note setlocale(): 2db, except to
find out what the current locale is.  But since the return value can
only be used portably to restore it, that is not very useful (except
perhaps to find out whether or not the locale is ‘C’).

When Python code uses the ‘locale’ module to change the locale, this
also affects the embedding application.  If the embedding application
doesn’t want this to happen, it should remove the ‘_locale’ extension
module (which does all the work) from the table of built-in modules in
the ‘config.c’ file, and make sure that the ‘_locale’ module is not
accessible as a shared library.


File: python.info,  Node: Access to message catalogs,  Prev: For extension writers and programs that embed Python,  Up: locale — Internationalization services

5.24.2.4 Access to message catalogs
...................................

 -- Function: locale.gettext (msg)

 -- Function: locale.dgettext (domain, msg)

 -- Function: locale.dcgettext (domain, msg, category)

 -- Function: locale.textdomain (domain)

 -- Function: locale.bindtextdomain (domain, dir)

 -- Function: locale.bind_textdomain_codeset (domain, codeset)

The locale module exposes the C library’s gettext interface on systems
that provide this interface.  It consists of the functions *note
gettext(): 63, *note dgettext(): 3fb4, *note dcgettext(): 3fb5, *note
textdomain(): 3fb6, *note bindtextdomain(): 3fb7, and *note
bind_textdomain_codeset(): 3fb8.  These are similar to the same
functions in the *note gettext: 63. module, but use the C library’s
binary format for message catalogs, and the C library’s search
algorithms for locating message catalogs.

Python applications should normally find no need to invoke these
functions, and should use *note gettext: 63. instead.  A known exception
to this rule are applications that link with additional C libraries
which internally invoke C functions ‘gettext’ or ‘dcgettext’.  For these
applications, it may be necessary to bind the text domain, so that the
libraries can properly locate their message catalogs.


File: python.info,  Node: Graphical user interfaces with Tk,  Next: Development Tools,  Prev: Internationalization,  Up: The Python Standard Library

5.25 Graphical user interfaces with Tk
======================================

Tk/Tcl has long been an integral part of Python.  It provides a robust
and platform independent windowing toolkit, that is available to Python
programmers using the *note tkinter: f0. package, and its extension, the
*note tkinter.ttk: f9. module.

The *note tkinter: f0. package is a thin object-oriented layer on top of
Tcl/Tk.  To use ‘tkinter’, you don’t need to write Tcl code, but you
will need to consult the Tk documentation, and occasionally the Tcl
documentation.  ‘tkinter’ is a set of wrappers that implement the Tk
widgets as Python classes.

*note tkinter: f0.’s chief virtues are that it is fast, and that it
usually comes bundled with Python.  Although its standard documentation
is weak, good material is available, which includes: references,
tutorials, a book and others.  ‘tkinter’ is also famous for having an
outdated look and feel, which has been vastly improved in Tk 8.5.
Nevertheless, there are many other GUI libraries that you could be
interested in.  The Python wiki lists several alternative GUI frameworks
and tools(1).

* Menu:

* tkinter — Python interface to Tcl/Tk::
* tkinter.colorchooser — Color choosing dialog: tkinter colorchooser — Color choosing dialog.
* tkinter.font — Tkinter font wrapper: tkinter font — Tkinter font wrapper.
* Tkinter Dialogs::
* tkinter.messagebox — Tkinter message prompts: tkinter messagebox — Tkinter message prompts.
* tkinter.scrolledtext — Scrolled Text Widget: tkinter scrolledtext — Scrolled Text Widget.
* tkinter.dnd — Drag and drop support: tkinter dnd — Drag and drop support.
* tkinter.ttk — Tk themed widgets: tkinter ttk — Tk themed widgets.
* IDLE — Python editor and shell: IDLE — Python editor and shell<2>.
* turtle — Turtle graphics::

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/GuiProgramming


File: python.info,  Node: tkinter — Python interface to Tcl/Tk,  Next: tkinter colorchooser — Color choosing dialog,  Up: Graphical user interfaces with Tk

5.25.1 ‘tkinter’ — Python interface to Tcl/Tk
---------------------------------------------

'Source code:' Lib/tkinter/__init__.py(1)

__________________________________________________________________

The ‘tkinter’ package (“Tk interface”) is the standard Python interface
to the Tcl/Tk GUI toolkit.  Both Tk and ‘tkinter’ are available on most
Unix platforms, including macOS, as well as on Windows systems.

Running ‘python -m tkinter’ from the command line should open a window
demonstrating a simple Tk interface, letting you know that ‘tkinter’ is
properly installed on your system, and also showing what version of
Tcl/Tk is installed, so you can read the Tcl/Tk documentation specific
to that version.

Tkinter supports a range of Tcl/Tk versions, built either with or
without thread support.  The official Python binary release bundles
Tcl/Tk 8.6 threaded.  See the source code for the *note _tkinter: 3.
module for more information about supported versions.

Tkinter is not a thin wrapper, but adds a fair amount of its own logic
to make the experience more pythonic.  This documentation will
concentrate on these additions and changes, and refer to the official
Tcl/Tk documentation for details that are unchanged.

     Note: Tcl/Tk 8.5 (2007) introduced a modern set of themed user
     interface components along with a new API to use them.  Both old
     and new APIs are still available.  Most documentation you will find
     online still uses the old API and can be woefully outdated.

See also
........

   * 
     TkDocs(2)

          Extensive tutorial on creating user interfaces with Tkinter.
          Explains key concepts, and illustrates recommended approaches
          using the modern API.

   * 
     Tkinter 8.5 reference: a GUI for Python(3)

          Reference documentation for Tkinter 8.5 detailing available
          classes, methods, and options.

Tcl/Tk Resources:

   * 
     Tk commands(4)

          Comprehensive reference to each of the underlying Tcl/Tk
          commands used by Tkinter.

   * 
     Tcl/Tk Home Page(5)

          Additional documentation, and links to Tcl/Tk core
          development.

Books:

   * 
     Modern Tkinter for Busy Python Developers(6)

          By Mark Roseman.  (ISBN 978-1999149567)

   * 
     Python GUI programming with Tkinter(7)

          By Alan D. Moore.  (ISBN 978-1788835886)

   * 
     Programming Python(8)

          By Mark Lutz; has excellent coverage of Tkinter.  (ISBN
          978-0596158101)

   * 
     Tcl and the Tk Toolkit (2nd edition)(9)

          By John Ousterhout, inventor of Tcl/Tk, and Ken Jones; does
          not cover Tkinter.  (ISBN 978-0321336330)

* Menu:

* Architecture::
* Tkinter Modules::
* Tkinter Life Preserver::
* Threading model::
* Handy Reference::
* File Handlers::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/__init__.py

   (2) https://tkdocs.com/

   (3) https://www.tkdocs.com/shipman/

   (4) https://www.tcl.tk/man/tcl8.6/TkCmd/contents.htm

   (5) https://www.tcl.tk

   (6) https://tkdocs.com/book.html

   (7) 
https://www.packtpub.com/en-us/product/python-gui-programming-with-tkinter-9781788835886

   (8) https://learning-python.com/about-pp4e.html

   (9) https://www.amazon.com/exec/obidos/ASIN/032133633X


File: python.info,  Node: Architecture,  Next: Tkinter Modules,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.1 Architecture
.....................

Tcl/Tk is not a single library but rather consists of a few distinct
modules, each with separate functionality and its own official
documentation.  Python’s binary releases also ship an add-on module
together with it.

Tcl

     Tcl is a dynamic interpreted programming language, just like
     Python.  Though it can be used on its own as a general-purpose
     programming language, it is most commonly embedded into C
     applications as a scripting engine or an interface to the Tk
     toolkit.  The Tcl library has a C interface to create and manage
     one or more instances of a Tcl interpreter, run Tcl commands and
     scripts in those instances, and add custom commands implemented in
     either Tcl or C. Each interpreter has an event queue, and there are
     facilities to send events to it and process them.  Unlike Python,
     Tcl’s execution model is designed around cooperative multitasking,
     and Tkinter bridges this difference (see *note Threading model:
     3fc0. for details).

Tk

     Tk is a Tcl package(1) implemented in C that adds custom commands
     to create and manipulate GUI widgets.  Each *note Tk: 173f. object
     embeds its own Tcl interpreter instance with Tk loaded into it.
     Tk’s widgets are very customizable, though at the cost of a dated
     appearance.  Tk uses Tcl’s event queue to generate and process GUI
     events.

Ttk

     Themed Tk (Ttk) is a newer family of Tk widgets that provide a much
     better appearance on different platforms than many of the classic
     Tk widgets.  Ttk is distributed as part of Tk, starting with Tk
     version 8.5.  Python bindings are provided in a separate module,
     *note tkinter.ttk: f9.

Internally, Tk and Ttk use facilities of the underlying operating
system, i.e., Xlib on Unix/X11, Cocoa on macOS, GDI on Windows.

When your Python application uses a class in Tkinter, e.g., to create a
widget, the ‘tkinter’ module first assembles a Tcl/Tk command string.
It passes that Tcl command string to an internal *note _tkinter: 3.
binary module, which then calls the Tcl interpreter to evaluate it.  The
Tcl interpreter will then call into the Tk and/or Ttk packages, which
will in turn make calls to Xlib, Cocoa, or GDI.

   ---------- Footnotes ----------

   (1) https://wiki.tcl-lang.org/37432


File: python.info,  Node: Tkinter Modules,  Next: Tkinter Life Preserver,  Prev: Architecture,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.2 Tkinter Modules
........................

Support for Tkinter is spread across several modules.  Most applications
will need the main ‘tkinter’ module, as well as the *note tkinter.ttk:
f9. module, which provides the modern themed widget set and API:

     from tkinter import *
     from tkinter import ttk

 -- Class: tkinter.Tk (screenName=None, baseName=None, className='Tk',
          useTk=True, sync=False, use=None)

     Construct a toplevel Tk widget, which is usually the main window of
     an application, and initialize a Tcl interpreter for this widget.
     Each instance has its own associated Tcl interpreter.

     The ‘Tk’ class is typically instantiated using all default values.
     However, the following keyword arguments are currently recognized:

     'screenName'

          When given (as a string), sets the ‘DISPLAY’ environment
          variable.  (X11 only)

     'baseName'

          Name of the profile file.  By default, 'baseName' is derived
          from the program name (‘sys.argv[0]’).

     'className'

          Name of the widget class.  Used as a profile file and also as
          the name with which Tcl is invoked ('argv0' in 'interp').

     'useTk'

          If ‘True’, initialize the Tk subsystem.  The *note
          tkinter.Tcl(): 3fc2. function sets this to ‘False’.

     'sync'

          If ‘True’, execute all X server commands synchronously, so
          that errors are reported immediately.  Can be used for
          debugging.  (X11 only)

     'use'

          Specifies the 'id' of the window in which to embed the
          application, instead of it being created as an independent
          toplevel window.  'id' must be specified in the same way as
          the value for the -use option for toplevel widgets (that is,
          it has a form like that returned by ‘winfo_id()’).

          Note that on some platforms this will only work correctly if
          'id' refers to a Tk frame or toplevel that has its -container
          option enabled.

     ‘Tk’ reads and interprets profile files, named ‘.`className'.tcl’
     and ‘.`baseName'.tcl’, into the Tcl interpreter and calls *note
     exec(): 17f. on the contents of ‘.`className'.py’ and
     ‘.`baseName'.py’.  The path for the profile files is the ‘HOME’
     environment variable or, if that isn’t defined, then *note
     os.curdir: 29ac.

      -- Attribute: tk

          The Tk application object created by instantiating ‘Tk’.  This
          provides access to the Tcl interpreter.  Each widget that is
          attached the same instance of ‘Tk’ has the same value for its
          *note tk: 3fc3. attribute.

      -- Attribute: master

          The widget object that contains this widget.  For ‘Tk’, the
          ‘master’ is *note None: 678. because it is the main window.
          The terms 'master' and 'parent' are similar and sometimes used
          interchangeably as argument names; however, calling
          ‘winfo_parent()’ returns a string of the widget name whereas
          ‘master’ returns the object.  'parent'/'child' reflects the
          tree-like relationship while 'master' (or
          'container')/'content' reflects the container structure.

      -- Attribute: children

          The immediate descendants of this widget as a *note dict: 256.
          with the child widget names as the keys and the child instance
          objects as the values.

 -- Function: tkinter.Tcl (screenName=None, baseName=None,
          className='Tk', useTk=False)

     The ‘Tcl()’ function is a factory function which creates an object
     much like that created by the *note Tk: 173f. class, except that it
     does not initialize the Tk subsystem.  This is most often useful
     when driving the Tcl interpreter in an environment where one
     doesn’t want to create extraneous toplevel windows, or where one
     cannot (such as Unix/Linux systems without an X server).  An object
     created by the ‘Tcl()’ object can have a Toplevel window created
     (and the Tk subsystem initialized) by calling its ‘loadtk()’
     method.

The modules that provide Tk support include:

‘tkinter’

     Main Tkinter module.

*note tkinter.colorchooser: f1.

     Dialog to let the user choose a color.

*note tkinter.commondialog: f2.

     Base class for the dialogs defined in the other modules listed
     here.

*note tkinter.filedialog: f4.

     Common dialogs to allow the user to specify a file to open or save.

*note tkinter.font: f5.

     Utilities to help work with fonts.

*note tkinter.messagebox: f6.

     Access to standard Tk dialog boxes.

*note tkinter.scrolledtext: f7.

     Text widget with a vertical scroll bar built in.

*note tkinter.simpledialog: f8.

     Basic dialogs and convenience functions.

*note tkinter.ttk: f9.

     Themed widget set introduced in Tk 8.5, providing modern
     alternatives for many of the classic widgets in the main ‘tkinter’
     module.

Additional modules:

*note _tkinter: 3.

     A binary module that contains the low-level interface to Tcl/Tk.
     It is automatically imported by the main ‘tkinter’ module, and
     should never be used directly by application programmers.  It is
     usually a shared library (or DLL), but might in some cases be
     statically linked with the Python interpreter.

*note idlelib: 73.

     Python’s Integrated Development and Learning Environment (IDLE).
     Based on ‘tkinter’.

‘tkinter.constants’

     Symbolic constants that can be used in place of strings when
     passing various parameters to Tkinter calls.  Automatically
     imported by the main ‘tkinter’ module.

*note tkinter.dnd: f3.

     (experimental) Drag-and-drop support for ‘tkinter’.  This will
     become deprecated when it is replaced with the Tk DND.

*note turtle: 101.

     Turtle graphics in a Tk window.


File: python.info,  Node: Tkinter Life Preserver,  Next: Threading model,  Prev: Tkinter Modules,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.3 Tkinter Life Preserver
...............................

This section is not designed to be an exhaustive tutorial on either Tk
or Tkinter.  For that, refer to one of the external resources noted
earlier.  Instead, this section provides a very quick orientation to
what a Tkinter application looks like, identifies foundational Tk
concepts, and explains how the Tkinter wrapper is structured.

The remainder of this section will help you to identify the classes,
methods, and options you’ll need in your Tkinter application, and where
to find more detailed documentation on them, including in the official
Tcl/Tk reference manual.

* Menu:

* A Hello World Program::
* Important Tk Concepts::
* Understanding How Tkinter Wraps Tcl/Tk::
* How do I…? What option does…?::
* Navigating the Tcl/Tk Reference Manual::


File: python.info,  Node: A Hello World Program,  Next: Important Tk Concepts,  Up: Tkinter Life Preserver

5.25.1.4 A Hello World Program
..............................

We’ll start by walking through a “Hello World” application in Tkinter.
This isn’t the smallest one we could write, but has enough to illustrate
some key concepts you’ll need to know.

     from tkinter import *
     from tkinter import ttk
     root = Tk()
     frm = ttk.Frame(root, padding=10)
     frm.grid()
     ttk.Label(frm, text="Hello World!").grid(column=0, row=0)
     ttk.Button(frm, text="Quit", command=root.destroy).grid(column=1, row=0)
     root.mainloop()

After the imports, the next line creates an instance of the ‘Tk’ class,
which initializes Tk and creates its associated Tcl interpreter.  It
also creates a toplevel window, known as the root window, which serves
as the main window of the application.

The following line creates a frame widget, which in this case will
contain a label and a button we’ll create next.  The frame is fit inside
the root window.

The next line creates a label widget holding a static text string.  The
‘grid()’ method is used to specify the relative layout (position) of the
label within its containing frame widget, similar to how tables in HTML
work.

A button widget is then created, and placed to the right of the label.
When pressed, it will call the ‘destroy()’ method of the root window.

Finally, the ‘mainloop()’ method puts everything on the display, and
responds to user input until the program terminates.


File: python.info,  Node: Important Tk Concepts,  Next: Understanding How Tkinter Wraps Tcl/Tk,  Prev: A Hello World Program,  Up: Tkinter Life Preserver

5.25.1.5 Important Tk Concepts
..............................

Even this simple program illustrates the following key Tk concepts:

widgets

     A Tkinter user interface is made up of individual 'widgets'.  Each
     widget is represented as a Python object, instantiated from classes
     like ‘ttk.Frame’, ‘ttk.Label’, and ‘ttk.Button’.

widget hierarchy

     Widgets are arranged in a 'hierarchy'.  The label and button were
     contained within a frame, which in turn was contained within the
     root window.  When creating each 'child' widget, its 'parent'
     widget is passed as the first argument to the widget constructor.

configuration options

     Widgets have 'configuration options', which modify their appearance
     and behavior, such as the text to display in a label or button.
     Different classes of widgets will have different sets of options.

geometry management

     Widgets aren’t automatically added to the user interface when they
     are created.  A 'geometry manager' like ‘grid’ controls where in
     the user interface they are placed.

event loop

     Tkinter reacts to user input, changes from your program, and even
     refreshes the display only when actively running an 'event loop'.
     If your program isn’t running the event loop, your user interface
     won’t update.


File: python.info,  Node: Understanding How Tkinter Wraps Tcl/Tk,  Next: How do I…? What option does…?,  Prev: Important Tk Concepts,  Up: Tkinter Life Preserver

5.25.1.6 Understanding How Tkinter Wraps Tcl/Tk
...............................................

When your application uses Tkinter’s classes and methods, internally
Tkinter is assembling strings representing Tcl/Tk commands, and
executing those commands in the Tcl interpreter attached to your
application’s ‘Tk’ instance.

Whether it’s trying to navigate reference documentation, trying to find
the right method or option, adapting some existing code, or debugging
your Tkinter application, there are times that it will be useful to
understand what those underlying Tcl/Tk commands look like.

To illustrate, here is the Tcl/Tk equivalent of the main part of the
Tkinter script above.

     ttk::frame .frm -padding 10
     grid .frm
     grid [ttk::label .frm.lbl -text "Hello World!"] -column 0 -row 0
     grid [ttk::button .frm.btn -text "Quit" -command "destroy ."] -column 1 -row 0

Tcl’s syntax is similar to many shell languages, where the first word is
the command to be executed, with arguments to that command following it,
separated by spaces.  Without getting into too many details, notice the
following:

   * The commands used to create widgets (like ‘ttk::frame’) correspond
     to widget classes in Tkinter.

   * Tcl widget options (like ‘-text’) correspond to keyword arguments
     in Tkinter.

   * Widgets are referred to by a 'pathname' in Tcl (like ‘.frm.btn’),
     whereas Tkinter doesn’t use names but object references.

   * A widget’s place in the widget hierarchy is encoded in its
     (hierarchical) pathname, which uses a ‘.’ (dot) as a path
     separator.  The pathname for the root window is just ‘.’ (dot).  In
     Tkinter, the hierarchy is defined not by pathname but by specifying
     the parent widget when creating each child widget.

   * Operations which are implemented as separate 'commands' in Tcl
     (like ‘grid’ or ‘destroy’) are represented as 'methods' on Tkinter
     widget objects.  As you’ll see shortly, at other times Tcl uses
     what appear to be method calls on widget objects, which more
     closely mirror what is used in Tkinter.


File: python.info,  Node: How do I…? What option does…?,  Next: Navigating the Tcl/Tk Reference Manual,  Prev: Understanding How Tkinter Wraps Tcl/Tk,  Up: Tkinter Life Preserver

5.25.1.7 How do I…? What option does…?
......................................

If you’re not sure how to do something in Tkinter, and you can’t
immediately find it in the tutorial or reference documentation you’re
using, there are a few strategies that can be helpful.

First, remember that the details of how individual widgets work may vary
across different versions of both Tkinter and Tcl/Tk.  If you’re
searching documentation, make sure it corresponds to the Python and
Tcl/Tk versions installed on your system.

When searching for how to use an API, it helps to know the exact name of
the class, option, or method that you’re using.  Introspection, either
in an interactive Python shell or with *note print(): fae, can help you
identify what you need.

To find out what configuration options are available on any widget, call
its ‘configure()’ method, which returns a dictionary containing a
variety of information about each object, including its default and
current values.  Use ‘keys()’ to get just the names of each option.

     btn = ttk.Button(frm, ...)
     print(btn.configure().keys())

As most widgets have many configuration options in common, it can be
useful to find out which are specific to a particular widget class.
Comparing the list of options to that of a simpler widget, like a frame,
is one way to do that.

     print(set(btn.configure().keys()) - set(frm.configure().keys()))

Similarly, you can find the available methods for a widget object using
the standard *note dir(): 635. function.  If you try it, you’ll see
there are over 200 common widget methods, so again identifying those
specific to a widget class is helpful.

     print(dir(btn))
     print(set(dir(btn)) - set(dir(frm)))


File: python.info,  Node: Navigating the Tcl/Tk Reference Manual,  Prev: How do I…? What option does…?,  Up: Tkinter Life Preserver

5.25.1.8 Navigating the Tcl/Tk Reference Manual
...............................................

As noted, the official Tk commands(1) reference manual (man pages) is
often the most accurate description of what specific operations on
widgets do.  Even when you know the name of the option or method that
you need, you may still have a few places to look.

While all operations in Tkinter are implemented as method calls on
widget objects, you’ve seen that many Tcl/Tk operations appear as
commands that take a widget pathname as its first parameter, followed by
optional parameters, e.g.

     destroy .
     grid .frm.btn -column 0 -row 0

Others, however, look more like methods called on a widget object (in
fact, when you create a widget in Tcl/Tk, it creates a Tcl command with
the name of the widget pathname, with the first parameter to that
command being the name of a method to call).

     .frm.btn invoke
     .frm.lbl configure -text "Goodbye"

In the official Tcl/Tk reference documentation, you’ll find most
operations that look like method calls on the man page for a specific
widget (e.g., you’ll find the ‘invoke()’ method on the ttk::button(2)
man page), while functions that take a widget as a parameter often have
their own man page (e.g., grid(3)).

You’ll find many common options and methods in the options(4) or
ttk::widget(5) man pages, while others are found in the man page for a
specific widget class.

You’ll also find that many Tkinter methods have compound names, e.g.,
‘winfo_x()’, ‘winfo_height()’, ‘winfo_viewable()’.  You’d find
documentation for all of these in the winfo(6) man page.

     Note: Somewhat confusingly, there are also methods on all Tkinter
     widgets that don’t actually operate on the widget, but operate at a
     global scope, independent of any widget.  Examples are methods for
     accessing the clipboard or the system bell.  (They happen to be
     implemented as methods in the base ‘Widget’ class that all Tkinter
     widgets inherit from).

   ---------- Footnotes ----------

   (1) https://www.tcl.tk/man/tcl8.6/TkCmd/contents.htm

   (2) https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_button.htm

   (3) https://www.tcl.tk/man/tcl8.6/TkCmd/grid.htm

   (4) https://www.tcl.tk/man/tcl8.6/TkCmd/options.htm

   (5) https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_widget.htm

   (6) https://www.tcl.tk/man/tcl8.6/TkCmd/winfo.htm


File: python.info,  Node: Threading model,  Next: Handy Reference,  Prev: Tkinter Life Preserver,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.9 Threading model
........................

Python and Tcl/Tk have very different threading models, which ‘tkinter’
tries to bridge.  If you use threads, you may need to be aware of this.

A Python interpreter may have many threads associated with it.  In Tcl,
multiple threads can be created, but each thread has a separate Tcl
interpreter instance associated with it.  Threads can also create more
than one interpreter instance, though each interpreter instance can be
used only by the one thread that created it.

Each ‘Tk’ object created by ‘tkinter’ contains a Tcl interpreter.  It
also keeps track of which thread created that interpreter.  Calls to
‘tkinter’ can be made from any Python thread.  Internally, if a call
comes from a thread other than the one that created the ‘Tk’ object, an
event is posted to the interpreter’s event queue, and when executed, the
result is returned to the calling Python thread.

Tcl/Tk applications are normally event-driven, meaning that after
initialization, the interpreter runs an event loop (i.e.
‘Tk.mainloop()’) and responds to events.  Because it is single-threaded,
event handlers must respond quickly, otherwise they will block other
events from being processed.  To avoid this, any long-running
computations should not run in an event handler, but are either broken
into smaller pieces using timers, or run in another thread.  This is
different from many GUI toolkits where the GUI runs in a completely
separate thread from all application code including event handlers.

If the Tcl interpreter is not running the event loop and processing
events, any ‘tkinter’ calls made from threads other than the one running
the Tcl interpreter will fail.

A number of special cases exist:

   * Tcl/Tk libraries can be built so they are not thread-aware.  In
     this case, ‘tkinter’ calls the library from the originating Python
     thread, even if this is different than the thread that created the
     Tcl interpreter.  A global lock ensures only one call occurs at a
     time.

   * While ‘tkinter’ allows you to create more than one instance of a
     ‘Tk’ object (with its own interpreter), all interpreters that are
     part of the same thread share a common event queue, which gets ugly
     fast.  In practice, don’t create more than one instance of ‘Tk’ at
     a time.  Otherwise, it’s best to create them in separate threads
     and ensure you’re running a thread-aware Tcl/Tk build.

   * Blocking event handlers are not the only way to prevent the Tcl
     interpreter from reentering the event loop.  It is even possible to
     run multiple nested event loops or abandon the event loop entirely.
     If you’re doing anything tricky when it comes to events or threads,
     be aware of these possibilities.

   * There are a few select ‘tkinter’ functions that presently work only
     when called from the thread that created the Tcl interpreter.


File: python.info,  Node: Handy Reference,  Next: File Handlers,  Prev: Threading model,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.10 Handy Reference
.........................

* Menu:

* Setting Options::
* The Packer::
* Packer Options::
* Coupling Widget Variables::
* The Window Manager::
* Tk Option Data Types::
* Bindings and Events::
* The index Parameter::
* Images::


File: python.info,  Node: Setting Options,  Next: The Packer,  Up: Handy Reference

5.25.1.11 Setting Options
.........................

Options control things like the color and border width of a widget.
Options can be set in three ways:

At object creation time, using keyword arguments

          fred = Button(self, fg="red", bg="blue")

After object creation, treating the option name like a dictionary index

          fred["fg"] = "red"
          fred["bg"] = "blue"

Use the config() method to update multiple attrs subsequent to object creation

          fred.config(fg="red", bg="blue")

For a complete explanation of a given option and its behavior, see the
Tk man pages for the widget in question.

Note that the man pages list “STANDARD OPTIONS” and “WIDGET SPECIFIC
OPTIONS” for each widget.  The former is a list of options that are
common to many widgets, the latter are the options that are
idiosyncratic to that particular widget.  The Standard Options are
documented on the ‘options(3)(1)’ man page.

No distinction between standard and widget-specific options is made in
this document.  Some options don’t apply to some kinds of widgets.
Whether a given widget responds to a particular option depends on the
class of the widget; buttons have a ‘command’ option, labels do not.

The options supported by a given widget are listed in that widget’s man
page, or can be queried at runtime by calling the ‘config()’ method
without arguments, or by calling the ‘keys()’ method on that widget.
The return value of these calls is a dictionary whose key is the name of
the option as a string (for example, ‘'relief'’) and whose values are
5-tuples.

Some options, like ‘bg’ are synonyms for common options with long names
(‘bg’ is shorthand for “background”).  Passing the ‘config()’ method the
name of a shorthand option will return a 2-tuple, not 5-tuple.  The
2-tuple passed back will contain the name of the synonym and the “real”
option (such as ‘('bg', 'background')’).

Index       Meaning                               Example
                                                  
---------------------------------------------------------------------
                                                  
0           option name                           ‘'relief'’
                                                  
                                                  
1           option name for database lookup       ‘'relief'’
                                                  
                                                  
2           option class for database lookup      ‘'Relief'’
                                                  
                                                  
3           default value                         ‘'raised'’
                                                  
                                                  
4           current value                         ‘'groove'’
                                                  

Example:

     >>> print(fred.config())
     {'relief': ('relief', 'relief', 'Relief', 'raised', 'groove')}

Of course, the dictionary printed will include all the options available
and their values.  This is meant only as an example.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/options(3)


File: python.info,  Node: The Packer,  Next: Packer Options,  Prev: Setting Options,  Up: Handy Reference

5.25.1.12 The Packer
....................

The packer is one of Tk’s geometry-management mechanisms.  Geometry
managers are used to specify the relative positioning of widgets within
their container.  In contrast to the more cumbersome 'placer' (which is
used less commonly, and we do not cover here), the packer takes
qualitative relationship specification - 'above', 'to the left of',
'filling', etc - and works everything out to determine the exact
placement coordinates for you.

The size of any container widget is determined by the size of the
“content widgets” inside.  The packer is used to control where content
widgets appear inside the container into which they are packed.  You can
pack widgets into frames, and frames into other frames, in order to
achieve the kind of layout you desire.  Additionally, the arrangement is
dynamically adjusted to accommodate incremental changes to the
configuration, once it is packed.

Note that widgets do not appear until they have had their geometry
specified with a geometry manager.  It’s a common early mistake to leave
out the geometry specification, and then be surprised when the widget is
created but nothing appears.  A widget will appear only after it has
had, for example, the packer’s ‘pack()’ method applied to it.

The pack() method can be called with keyword-option/value pairs that
control where the widget is to appear within its container, and how it
is to behave when the main application window is resized.  Here are some
examples:

     fred.pack()                     # defaults to side = "top"
     fred.pack(side="left")
     fred.pack(expand=1)


File: python.info,  Node: Packer Options,  Next: Coupling Widget Variables,  Prev: The Packer,  Up: Handy Reference

5.25.1.13 Packer Options
........................

For more extensive information on the packer and the options that it can
take, see the man pages and page 183 of John Ousterhout’s book.

anchor

     Anchor type.  Denotes where the packer is to place each content in
     its parcel.

expand

     Boolean, ‘0’ or ‘1’.

fill

     Legal values: ‘'x'’, ‘'y'’, ‘'both'’, ‘'none'’.

ipadx and ipady

     A distance - designating internal padding on each side of the
     content.

padx and pady

     A distance - designating external padding on each side of the
     content.

side

     Legal values are: ‘'left'’, ‘'right'’, ‘'top'’, ‘'bottom'’.


File: python.info,  Node: Coupling Widget Variables,  Next: The Window Manager,  Prev: Packer Options,  Up: Handy Reference

5.25.1.14 Coupling Widget Variables
...................................

The current-value setting of some widgets (like text entry widgets) can
be connected directly to application variables by using special options.
These options are ‘variable’, ‘textvariable’, ‘onvalue’, ‘offvalue’, and
‘value’.  This connection works both ways: if the variable changes for
any reason, the widget it’s connected to will be updated to reflect the
new value.

Unfortunately, in the current implementation of ‘tkinter’ it is not
possible to hand over an arbitrary Python variable to a widget through a
‘variable’ or ‘textvariable’ option.  The only kinds of variables for
which this works are variables that are subclassed from a class called
Variable, defined in ‘tkinter’.

There are many useful subclasses of Variable already defined:
‘StringVar’, ‘IntVar’, ‘DoubleVar’, and ‘BooleanVar’.  To read the
current value of such a variable, call the ‘get()’ method on it, and to
change its value you call the ‘set()’ method.  If you follow this
protocol, the widget will always track the value of the variable, with
no further intervention on your part.

For example:

     import tkinter as tk

     class App(tk.Frame):
         def __init__(self, master):
             super().__init__(master)
             self.pack()

             self.entrythingy = tk.Entry()
             self.entrythingy.pack()

             # Create the application variable.
             self.contents = tk.StringVar()
             # Set it to some value.
             self.contents.set("this is a variable")
             # Tell the entry widget to watch this variable.
             self.entrythingy["textvariable"] = self.contents

             # Define a callback for when the user hits return.
             # It prints the current value of the variable.
             self.entrythingy.bind('<Key-Return>',
                                  self.print_contents)

         def print_contents(self, event):
             print("Hi. The current entry content is:",
                   self.contents.get())

     root = tk.Tk()
     myapp = App(root)
     myapp.mainloop()


File: python.info,  Node: The Window Manager,  Next: Tk Option Data Types,  Prev: Coupling Widget Variables,  Up: Handy Reference

5.25.1.15 The Window Manager
............................

In Tk, there is a utility command, ‘wm’, for interacting with the window
manager.  Options to the ‘wm’ command allow you to control things like
titles, placement, icon bitmaps, and the like.  In ‘tkinter’, these
commands have been implemented as methods on the ‘Wm’ class.  Toplevel
widgets are subclassed from the ‘Wm’ class, and so can call the ‘Wm’
methods directly.

To get at the toplevel window that contains a given widget, you can
often just refer to the widget’s ‘master’.  Of course if the widget has
been packed inside of a frame, the ‘master’ won’t represent a toplevel
window.  To get at the toplevel window that contains an arbitrary
widget, you can call the ‘_root()’ method.  This method begins with an
underscore to denote the fact that this function is part of the
implementation, and not an interface to Tk functionality.

Here are some examples of typical usage:

     import tkinter as tk

     class App(tk.Frame):
         def __init__(self, master=None):
             super().__init__(master)
             self.pack()

     # create the application
     myapp = App()

     #
     # here are method calls to the window manager class
     #
     myapp.master.title("My Do-Nothing Application")
     myapp.master.maxsize(1000, 400)

     # start the program
     myapp.mainloop()


File: python.info,  Node: Tk Option Data Types,  Next: Bindings and Events,  Prev: The Window Manager,  Up: Handy Reference

5.25.1.16 Tk Option Data Types
..............................

anchor

     Legal values are points of the compass: ‘"n"’, ‘"ne"’, ‘"e"’,
     ‘"se"’, ‘"s"’, ‘"sw"’, ‘"w"’, ‘"nw"’, and also ‘"center"’.

bitmap

     There are eight built-in, named bitmaps: ‘'error'’, ‘'gray25'’,
     ‘'gray50'’, ‘'hourglass'’, ‘'info'’, ‘'questhead'’, ‘'question'’,
     ‘'warning'’.  To specify an X bitmap filename, give the full path
     to the file, preceded with an ‘@’, as in
     ‘"@/usr/contrib/bitmap/gumby.bit"’.

boolean

     You can pass integers 0 or 1 or the strings ‘"yes"’ or ‘"no"’.

callback

     This is any Python function that takes no arguments.  For example:

          def print_it():
              print("hi there")
          fred["command"] = print_it

color

     Colors can be given as the names of X colors in the rgb.txt file,
     or as strings representing RGB values in 4 bit: ‘"#RGB"’, 8 bit:
     ‘"#RRGGBB"’, 12 bit: ‘"#RRRGGGBBB"’, or 16 bit: ‘"#RRRRGGGGBBBB"’
     ranges, where R,G,B here represent any legal hex digit.  See page
     160 of Ousterhout’s book for details.

cursor

     The standard X cursor names from ‘cursorfont.h’ can be used,
     without the ‘XC_’ prefix.  For example to get a hand cursor
     (‘XC_hand2’), use the string ‘"hand2"’.  You can also specify a
     bitmap and mask file of your own.  See page 179 of Ousterhout’s
     book.

distance

     Screen distances can be specified in either pixels or absolute
     distances.  Pixels are given as numbers and absolute distances as
     strings, with the trailing character denoting units: ‘c’ for
     centimetres, ‘i’ for inches, ‘m’ for millimetres, ‘p’ for printer’s
     points.  For example, 3.5 inches is expressed as ‘"3.5i"’.

font

     Tk uses a list font name format, such as ‘{courier 10 bold}’.  Font
     sizes with positive numbers are measured in points; sizes with
     negative numbers are measured in pixels.

geometry

     This is a string of the form ‘widthxheight’, where width and height
     are measured in pixels for most widgets (in characters for widgets
     displaying text).  For example: ‘fred["geometry"] = "200x100"’.

justify

     Legal values are the strings: ‘"left"’, ‘"center"’, and ‘"right"’.

region

     This is a string with four space-delimited elements, each of which
     is a legal distance (see above).  For example: ‘"2 3 4 5"’ and ‘"3i
     2i 4.5i 2i"’ and ‘"3c 2c 4c 10.43c"’ are all legal regions.

relief

     Determines what the border style of a widget will be.  Legal values
     are: ‘"raised"’, ‘"sunken"’, ‘"flat"’, ‘"groove"’, and ‘"ridge"’.

scrollcommand

     This is almost always the ‘set()’ method of some scrollbar widget,
     but can be any widget method that takes a single argument.

wrap

     Must be one of: ‘"none"’, ‘"char"’, or ‘"word"’.


File: python.info,  Node: Bindings and Events,  Next: The index Parameter,  Prev: Tk Option Data Types,  Up: Handy Reference

5.25.1.17 Bindings and Events
.............................

The bind method from the widget command allows you to watch for certain
events and to have a callback function trigger when that event type
occurs.  The form of the bind method is:

     def bind(self, sequence, func, add=''):

where:

sequence

     is a string that denotes the target kind of event.  (See the
     ‘bind(3tk)(1)’ man page, and page 201 of John Ousterhout’s book,
     ‘Tcl and the Tk Toolkit (2nd edition)’, for details).

func

     is a Python function, taking one argument, to be invoked when the
     event occurs.  An Event instance will be passed as the argument.
     (Functions deployed this way are commonly known as 'callbacks'.)

add

     is optional, either ‘''’ or ‘'+'’.  Passing an empty string denotes
     that this binding is to replace any other bindings that this event
     is associated with.  Passing a ‘'+'’ means that this function is to
     be added to the list of functions bound to this event type.

For example:

     def turn_red(self, event):
         event.widget["activeforeground"] = "red"

     self.button.bind("<Enter>", self.turn_red)

Notice how the widget field of the event is being accessed in the
‘turn_red()’ callback.  This field contains the widget that caught the X
event.  The following table lists the other event fields you can access,
and how they are denoted in Tk, which can be useful when referring to
the Tk man pages.

Tk       Tkinter Event Field       Tk       Tkinter Event Field
                                            
----------------------------------------------------------------------
                                            
%f       focus                     %A       char
                                            
                                            
%h       height                    %E       send_event
                                            
                                            
%k       keycode                   %K       keysym
                                            
                                            
%s       state                     %N       keysym_num
                                            
                                            
%t       time                      %T       type
                                            
                                            
%w       width                     %W       widget
                                            
                                            
%x       x                         %X       x_root
                                            
                                            
%y       y                         %Y       y_root
                                            

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/bind(3tk)


File: python.info,  Node: The index Parameter,  Next: Images,  Prev: Bindings and Events,  Up: Handy Reference

5.25.1.18 The index Parameter
.............................

A number of widgets require “index” parameters to be passed.  These are
used to point at a specific place in a Text widget, or to particular
characters in an Entry widget, or to particular menu items in a Menu
widget.

Entry widget indexes (index, view index, etc.)

     Entry widgets have options that refer to character positions in the
     text being displayed.  You can use these ‘tkinter’ functions to
     access these special points in text widgets:

Text widget indexes

     The index notation for Text widgets is very rich and is best
     described in the Tk man pages.

Menu indexes (menu.invoke(), menu.entryconfig(), etc.)

     Some options and methods for menus manipulate specific menu
     entries.  Anytime a menu index is needed for an option or a
     parameter, you may pass in:

        * an integer which refers to the numeric position of the entry
          in the widget, counted from the top, starting with 0;

        * the string ‘"active"’, which refers to the menu position that
          is currently under the cursor;

        * the string ‘"last"’ which refers to the last menu item;

        * An integer preceded by ‘@’, as in ‘@6’, where the integer is
          interpreted as a y pixel coordinate in the menu’s coordinate
          system;

        * the string ‘"none"’, which indicates no menu entry at all,
          most often used with menu.activate() to deactivate all
          entries, and finally,

        * a text string that is pattern matched against the label of the
          menu entry, as scanned from the top of the menu to the bottom.
          Note that this index type is considered after all the others,
          which means that matches for menu items labelled ‘last’,
          ‘active’, or ‘none’ may be interpreted as the above literals,
          instead.


File: python.info,  Node: Images,  Prev: The index Parameter,  Up: Handy Reference

5.25.1.19 Images
................

Images of different formats can be created through the corresponding
subclass of ‘tkinter.Image’:

   * ‘BitmapImage’ for images in XBM format.

   * ‘PhotoImage’ for images in PGM, PPM, GIF and PNG formats.  The
     latter is supported starting with Tk 8.6.

Either type of image is created through either the ‘file’ or the ‘data’
option (other options are available as well).

Changed in version 3.13: Added the ‘PhotoImage’ method ‘copy_replace()’
to copy a region from one image to other image, possibly with pixel
zooming and/or subsampling.  Add 'from_coords' parameter to ‘PhotoImage’
methods ‘copy()’, ‘zoom()’ and ‘subsample()’.  Add 'zoom' and
'subsample' parameters to ‘PhotoImage’ method ‘copy()’.

The image object can then be used wherever an ‘image’ option is
supported by some widget (e.g.  labels, buttons, menus).  In these
cases, Tk will not keep a reference to the image.  When the last Python
reference to the image object is deleted, the image data is deleted as
well, and Tk will display an empty box wherever the image was used.

See also
........

The Pillow(1) package adds support for formats such as BMP, JPEG, TIFF,
and WebP, among others.

   ---------- Footnotes ----------

   (1) https://python-pillow.org/


File: python.info,  Node: File Handlers,  Prev: Handy Reference,  Up: tkinter — Python interface to Tcl/Tk

5.25.1.20 File Handlers
.......................

Tk allows you to register and unregister a callback function which will
be called from the Tk mainloop when I/O is possible on a file
descriptor.  Only one handler may be registered per file descriptor.
Example code:

     import tkinter
     widget = tkinter.Tk()
     mask = tkinter.READABLE | tkinter.WRITABLE
     widget.tk.createfilehandler(file, mask, callback)
     ...
     widget.tk.deletefilehandler(file)

This feature is not available on Windows.

Since you don’t know how many bytes are available for reading, you may
not want to use the *note BufferedIOBase: 697. or *note TextIOBase: 698.
*note read(): 1372. or *note readline(): 1373. methods, since these will
insist on reading a predefined number of bytes.  For sockets, the *note
recv(): dd2. or *note recvfrom(): dd3. methods will work fine; for other
files, use raw reads or ‘os.read(file.fileno(), maxbytecount)’.

 -- Method: Widget.tk.createfilehandler (file, mask, func)

     Registers the file handler callback function 'func'.  The 'file'
     argument may either be an object with a *note fileno(): 15f5.
     method (such as a file or socket object), or an integer file
     descriptor.  The 'mask' argument is an ORed combination of any of
     the three constants below.  The callback is called as follows:

          callback(file, mask)

 -- Method: Widget.tk.deletefilehandler (file)

     Unregisters a file handler.

 -- Data: _tkinter.READABLE
 -- Data: _tkinter.WRITABLE
 -- Data: _tkinter.EXCEPTION

     Constants used in the 'mask' arguments.


File: python.info,  Node: tkinter colorchooser — Color choosing dialog,  Next: tkinter font — Tkinter font wrapper,  Prev: tkinter — Python interface to Tcl/Tk,  Up: Graphical user interfaces with Tk

5.25.2 ‘tkinter.colorchooser’ — Color choosing dialog
-----------------------------------------------------

'Source code:' Lib/tkinter/colorchooser.py(1)

__________________________________________________________________

The ‘tkinter.colorchooser’ module provides the *note Chooser: 3fe2.
class as an interface to the native color picker dialog.  ‘Chooser’
implements a modal color choosing dialog window.  The ‘Chooser’ class
inherits from the *note Dialog: 3fe3. class.

 -- Class: tkinter.colorchooser.Chooser (master=None, **options)

 -- Function: tkinter.colorchooser.askcolor (color=None, **options)

     Create a color choosing dialog.  A call to this method will show
     the window, wait for the user to make a selection, and return the
     selected color (or ‘None’) to the caller.

See also
........

Module *note tkinter.commondialog: f2.

     Tkinter standard dialog module

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/colorchooser.py


File: python.info,  Node: tkinter font — Tkinter font wrapper,  Next: Tkinter Dialogs,  Prev: tkinter colorchooser — Color choosing dialog,  Up: Graphical user interfaces with Tk

5.25.3 ‘tkinter.font’ — Tkinter font wrapper
--------------------------------------------

'Source code:' Lib/tkinter/font.py(1)

__________________________________________________________________

The ‘tkinter.font’ module provides the *note Font: 1a74. class for
creating and using named fonts.

The different font weights and slants are:

 -- Data: tkinter.font.NORMAL
 -- Data: tkinter.font.BOLD
 -- Data: tkinter.font.ITALIC
 -- Data: tkinter.font.ROMAN

 -- Class: tkinter.font.Font (root=None, font=None, name=None,
          exists=False, **options)

     The ‘Font’ class represents a named font.  'Font' instances are
     given unique names and can be specified by their family, size, and
     style configuration.  Named fonts are Tk’s method of creating and
     identifying fonts as a single object, rather than specifying a font
     by its attributes with each occurrence.

          arguments:

                    'font' - font specifier tuple (family, size, options)
                    'name' - unique font name
                    'exists' - self points to existing named font if true

          additional keyword options (ignored if 'font' is specified):

                    'family' - font family i.e. Courier, Times
                    'size' - font size
                         If 'size' is positive it is interpreted as size in points.
                         If 'size' is a negative number its absolute value is treated
                         as size in pixels.
                    'weight' - font emphasis (NORMAL, BOLD)
                    'slant' - ROMAN, ITALIC
                    'underline' - font underlining (0 - none, 1 - underline)
                    'overstrike' - font strikeout (0 - none, 1 - strikeout)

      -- Method: actual (option=None, displayof=None)

          Return the attributes of the font.

      -- Method: cget (option)

          Retrieve an attribute of the font.

      -- Method: config (**options)

          Modify attributes of the font.

      -- Method: copy ()

          Return new instance of the current font.

      -- Method: measure (text, displayof=None)

          Return amount of space the text would occupy on the specified
          display when formatted in the current font.  If no display is
          specified then the main application window is assumed.

      -- Method: metrics (*options, **kw)

          Return font-specific data.  Options include:

          'ascent' - distance between baseline and highest point that a

               character of the font can occupy

          'descent' - distance between baseline and lowest point that a

               character of the font can occupy

          'linespace' - minimum vertical separation necessary between any two

               characters of the font that ensures no vertical overlap
               between lines.

          'fixed' - 1 if font is fixed-width else 0

 -- Function: tkinter.font.families (root=None, displayof=None)

     Return the different font families.

 -- Function: tkinter.font.names (root=None)

     Return the names of defined fonts.

 -- Function: tkinter.font.nametofont (name, root=None)

     Return a *note Font: 1a74. representation of a tk named font.

     Changed in version 3.10: The 'root' parameter was added.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tkinter/font.py


File: python.info,  Node: Tkinter Dialogs,  Next: tkinter messagebox — Tkinter message prompts,  Prev: tkinter font — Tkinter font wrapper,  Up: Graphical user interfaces with Tk

5.25.4 Tkinter Dialogs
----------------------

* Menu:

* tkinter.simpledialog — Standard Tkinter input dialogs: tkinter simpledialog — Standard Tkinter input dialogs.
* tkinter.filedialog — File selection dialogs: tkinter filedialog — File selection dialogs.
* tkinter.commondialog — Dialog window templates: tkinter commondialog — Dialog window templates.


File: python.info,  Node: tkinter simpledialog — Standard Tkinter input dialogs,  Next: tkinter filedialog — File selection dialogs,  Up: Tkinter Dialogs

5.25.4.1 ‘tkinter.simpledialog’ — Standard Tkinter input dialogs
................................................................

'Source code:' Lib/tkinter/simpledialog.py(1)

__________________________________________________________________

The ‘tkinter.simpledialog’ module contains convenience classes and
functions for creating simple modal dialogs to get a value from the
user.

 -- Function: tkinter.simpledialog.askfloat (title, prompt, **kw)
 -- Function: tkinter.simpledialog.askinteger (title, prompt, **kw)
 -- Function: tkinter.simpledialog.askstring (title, prompt, **kw)

     The above three functions provide dialogs that prompt the user to
     enter a value of the desired type.

 -- Class: tkinter.simpledialog.Dialog (parent, title=None)

     The base class for custom dialogs.

      -- Method: body (master)

          Override to construct the dialog’s interface and return the
          widget that should have initial focus.

      -- Method: buttonbox ()

          Default behaviour adds OK and Cancel buttons.  Override for
          custom button layouts.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/simpledialog.py


File: python.info,  Node: tkinter filedialog — File selection dialogs,  Next: tkinter commondialog — Dialog window templates,  Prev: tkinter simpledialog — Standard Tkinter input dialogs,  Up: Tkinter Dialogs

5.25.4.2 ‘tkinter.filedialog’ — File selection dialogs
......................................................

'Source code:' Lib/tkinter/filedialog.py(1)

__________________________________________________________________

The ‘tkinter.filedialog’ module provides classes and factory functions
for creating file/directory selection windows.

* Menu:

* Native Load/Save Dialogs::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/filedialog.py


File: python.info,  Node: Native Load/Save Dialogs,  Up: tkinter filedialog — File selection dialogs

5.25.4.3 Native Load/Save Dialogs
.................................

The following classes and functions provide file dialog windows that
combine a native look-and-feel with configuration options to customize
behaviour.  The following keyword arguments are applicable to the
classes and functions listed below:

          'parent' - the window to place the dialog on top of

          'title' - the title of the window

          'initialdir' - the directory that the dialog starts in

          'initialfile' - the file selected upon opening of the dialog

          'filetypes' - a sequence of (label, pattern) tuples, ‘*’ wildcard is allowed

          'defaultextension' - default extension to append to file (save dialogs)

          'multiple' - when true, selection of multiple items is allowed

'Static factory functions'

The below functions when called create a modal, native look-and-feel
dialog, wait for the user’s selection, then return the selected value(s)
or ‘None’ to the caller.

 -- Function: tkinter.filedialog.askopenfile (mode='r', **options)
 -- Function: tkinter.filedialog.askopenfiles (mode='r', **options)

     The above two functions create an *note Open: 4001. dialog and
     return the opened file object(s) in read-only mode.

 -- Function: tkinter.filedialog.asksaveasfile (mode='w', **options)

     Create a *note SaveAs: 4003. dialog and return a file object opened
     in write-only mode.

 -- Function: tkinter.filedialog.askopenfilename (**options)
 -- Function: tkinter.filedialog.askopenfilenames (**options)

     The above two functions create an *note Open: 4001. dialog and
     return the selected filename(s) that correspond to existing
     file(s).

 -- Function: tkinter.filedialog.asksaveasfilename (**options)

     Create a *note SaveAs: 4003. dialog and return the selected
     filename.

 -- Function: tkinter.filedialog.askdirectory (**options)

          Prompt user to select a directory.
          Additional keyword option:
               'mustexist' - determines if selection must be an existing directory.

 -- Class: tkinter.filedialog.Open (master=None, **options)
 -- Class: tkinter.filedialog.SaveAs (master=None, **options)

     The above two classes provide native dialog windows for saving and
     loading files.

'Convenience classes'

The below classes are used for creating file/directory windows from
scratch.  These do not emulate the native look-and-feel of the platform.

 -- Class: tkinter.filedialog.Directory (master=None, **options)

     Create a dialog prompting the user to select a directory.

     Note: The 'FileDialog' class should be subclassed for custom event
     handling and behaviour.

 -- Class: tkinter.filedialog.FileDialog (master, title=None)

     Create a basic file selection dialog.

      -- Method: cancel_command (event=None)

          Trigger the termination of the dialog window.

      -- Method: dirs_double_event (event)

          Event handler for double-click event on directory.

      -- Method: dirs_select_event (event)

          Event handler for click event on directory.

      -- Method: files_double_event (event)

          Event handler for double-click event on file.

      -- Method: files_select_event (event)

          Event handler for single-click event on file.

      -- Method: filter_command (event=None)

          Filter the files by directory.

      -- Method: get_filter ()

          Retrieve the file filter currently in use.

      -- Method: get_selection ()

          Retrieve the currently selected item.

      -- Method: go (dir_or_file=os.curdir, pattern='*', default='',
               key=None)

          Render dialog and start event loop.

      -- Method: ok_event (event)

          Exit dialog returning current selection.

      -- Method: quit (how=None)

          Exit dialog returning filename, if any.

      -- Method: set_filter (dir, pat)

          Set the file filter.

      -- Method: set_selection (file)

          Update the current file selection to 'file'.

 -- Class: tkinter.filedialog.LoadFileDialog (master, title=None)

     A subclass of FileDialog that creates a dialog window for selecting
     an existing file.

      -- Method: ok_command ()

          Test that a file is provided and that the selection indicates
          an already existing file.

 -- Class: tkinter.filedialog.SaveFileDialog (master, title=None)

     A subclass of FileDialog that creates a dialog window for selecting
     a destination file.

      -- Method: ok_command ()

          Test whether or not the selection points to a valid file that
          is not a directory.  Confirmation is required if an already
          existing file is selected.


File: python.info,  Node: tkinter commondialog — Dialog window templates,  Prev: tkinter filedialog — File selection dialogs,  Up: Tkinter Dialogs

5.25.4.4 ‘tkinter.commondialog’ — Dialog window templates
.........................................................

'Source code:' Lib/tkinter/commondialog.py(1)

__________________________________________________________________

The ‘tkinter.commondialog’ module provides the *note Dialog: 3fe3. class
that is the base class for dialogs defined in other supporting modules.

 -- Class: tkinter.commondialog.Dialog (master=None, **options)

      -- Method: show (**options)

          Render the Dialog window.

See also
........

Modules *note tkinter.messagebox: f6, *note Reading and Writing Files:
1e1e.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/commondialog.py


File: python.info,  Node: tkinter messagebox — Tkinter message prompts,  Next: tkinter scrolledtext — Scrolled Text Widget,  Prev: Tkinter Dialogs,  Up: Graphical user interfaces with Tk

5.25.5 ‘tkinter.messagebox’ — Tkinter message prompts
-----------------------------------------------------

'Source code:' Lib/tkinter/messagebox.py(1)

__________________________________________________________________

The ‘tkinter.messagebox’ module provides a template base class as well
as a variety of convenience methods for commonly used configurations.
The message boxes are modal and will return a subset of (‘True’,
‘False’, ‘None’, *note OK: 4020, *note CANCEL: 4021, *note YES: 4022,
*note NO: 4023.) based on the user’s selection.  Common message box
styles and layouts include but are not limited to:

[image src="python-figures/tk_msg.png"]


Figure
 -- Class: tkinter.messagebox.Message (master=None, **options)

     Create a message window with an application-specified message, an
     icon and a set of buttons.  Each of the buttons in the message
     window is identified by a unique symbolic name (see the 'type'
     options).

     The following options are supported:

          'command'

               Specifies the function to invoke when the user closes the
               dialog.  The name of the button clicked by the user to
               close the dialog is passed as argument.  This is only
               available on macOS.

          'default'

               Gives the *note symbolic name: 4025. of the default
               button for this message window (*note OK: 4020, *note
               CANCEL: 4021, and so on).  If this option is not
               specified, the first button in the dialog will be made
               the default.

          'detail'

               Specifies an auxiliary message to the main message given
               by the 'message' option.  The message detail will be
               presented beneath the main message and, where supported
               by the OS, in a less emphasized font than the main
               message.

          'icon'

               Specifies an *note icon: 4026. to display.  If this
               option is not specified, then the *note INFO: 4027. icon
               will be displayed.

          'message'

               Specifies the message to display in this message box.
               The default value is an empty string.

          'parent'

               Makes the specified window the logical parent of the
               message box.  The message box is displayed on top of its
               parent window.

          'title'

               Specifies a string to display as the title of the message
               box.  This option is ignored on macOS, where platform
               guidelines forbid the use of a title on this kind of
               dialog.

          'type'

               Arranges for a *note predefined set of buttons: 4028. to
               be displayed.

      -- Method: show (**options)

          Display a message window and wait for the user to select one
          of the buttons.  Then return the symbolic name of the selected
          button.  Keyword arguments can override options specified in
          the constructor.

'Information message box'

 -- Function: tkinter.messagebox.showinfo (title=None, message=None,
          **options)

     Creates and displays an information message box with the specified
     title and message.

'Warning message boxes'

 -- Function: tkinter.messagebox.showwarning (title=None, message=None,
          **options)

     Creates and displays a warning message box with the specified title
     and message.

 -- Function: tkinter.messagebox.showerror (title=None, message=None,
          **options)

     Creates and displays an error message box with the specified title
     and message.

'Question message boxes'

 -- Function: tkinter.messagebox.askquestion (title=None, message=None,
          *, type=YESNO, **options)

     Ask a question.  By default shows buttons *note YES: 4022. and
     *note NO: 4023.  Returns the symbolic name of the selected button.

 -- Function: tkinter.messagebox.askokcancel (title=None, message=None,
          **options)

     Ask if operation should proceed.  Shows buttons *note OK: 4020. and
     *note CANCEL: 4021.  Returns ‘True’ if the answer is ok and ‘False’
     otherwise.

 -- Function: tkinter.messagebox.askretrycancel (title=None,
          message=None, **options)

     Ask if operation should be retried.  Shows buttons *note RETRY:
     4030. and *note CANCEL: 4021.  Return ‘True’ if the answer is yes
     and ‘False’ otherwise.

 -- Function: tkinter.messagebox.askyesno (title=None, message=None,
          **options)

     Ask a question.  Shows buttons *note YES: 4022. and *note NO: 4023.
     Returns ‘True’ if the answer is yes and ‘False’ otherwise.

 -- Function: tkinter.messagebox.askyesnocancel (title=None,
          message=None, **options)

     Ask a question.  Shows buttons *note YES: 4022, *note NO: 4023. and
     *note CANCEL: 4021.  Return ‘True’ if the answer is yes, ‘None’ if
     cancelled, and ‘False’ otherwise.
Symbolic names of buttons:

 -- Data: tkinter.messagebox.ABORT = 'abort'

 -- Data: tkinter.messagebox.RETRY = 'retry'

 -- Data: tkinter.messagebox.IGNORE = 'ignore'

 -- Data: tkinter.messagebox.OK = 'ok'

 -- Data: tkinter.messagebox.CANCEL = 'cancel'

 -- Data: tkinter.messagebox.YES = 'yes'

 -- Data: tkinter.messagebox.NO = 'no'
Predefined sets of buttons:

 -- Data: tkinter.messagebox.ABORTRETRYIGNORE = 'abortretryignore'

     Displays three buttons whose symbolic names are *note ABORT: 4033,
     *note RETRY: 4030. and *note IGNORE: 4034.

 -- Data: tkinter.messagebox.OK = 'ok'

     Displays one button whose symbolic name is ‘OK’.

 -- Data: tkinter.messagebox.OKCANCEL = 'okcancel'

     Displays two buttons whose symbolic names are *note OK: 4020. and
     *note CANCEL: 4021.

 -- Data: tkinter.messagebox.RETRYCANCEL = 'retrycancel'

     Displays two buttons whose symbolic names are *note RETRY: 4030.
     and *note CANCEL: 4021.

 -- Data: tkinter.messagebox.YESNO = 'yesno'

     Displays two buttons whose symbolic names are *note YES: 4022. and
     *note NO: 4023.

 -- Data: tkinter.messagebox.YESNOCANCEL = 'yesnocancel'

     Displays three buttons whose symbolic names are *note YES: 4022,
     *note NO: 4023. and *note CANCEL: 4021.
Icon images:

 -- Data: tkinter.messagebox.ERROR = 'error'

 -- Data: tkinter.messagebox.INFO = 'info'

 -- Data: tkinter.messagebox.QUESTION = 'question'

 -- Data: tkinter.messagebox.WARNING = 'warning'

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/messagebox.py


File: python.info,  Node: tkinter scrolledtext — Scrolled Text Widget,  Next: tkinter dnd — Drag and drop support,  Prev: tkinter messagebox — Tkinter message prompts,  Up: Graphical user interfaces with Tk

5.25.6 ‘tkinter.scrolledtext’ — Scrolled Text Widget
----------------------------------------------------

'Source code:' Lib/tkinter/scrolledtext.py(1)

__________________________________________________________________

The ‘tkinter.scrolledtext’ module provides a class of the same name
which implements a basic text widget which has a vertical scroll bar
configured to do the “right thing.” Using the *note ScrolledText: 4040.
class is a lot easier than setting up a text widget and scroll bar
directly.

The text widget and scrollbar are packed together in a ‘Frame’, and the
methods of the ‘Grid’ and ‘Pack’ geometry managers are acquired from the
‘Frame’ object.  This allows the *note ScrolledText: 4040. widget to be
used directly to achieve most normal geometry management behavior.

Should more specific control be necessary, the following attributes are
available:

 -- Class: tkinter.scrolledtext.ScrolledText (master=None, **kw)

      -- Attribute: frame

          The frame which surrounds the text and scroll bar widgets.

      -- Attribute: vbar

          The scroll bar widget.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/tkinter/scrolledtext.py


File: python.info,  Node: tkinter dnd — Drag and drop support,  Next: tkinter ttk — Tk themed widgets,  Prev: tkinter scrolledtext — Scrolled Text Widget,  Up: Graphical user interfaces with Tk

5.25.7 ‘tkinter.dnd’ — Drag and drop support
--------------------------------------------

'Source code:' Lib/tkinter/dnd.py(1)

__________________________________________________________________

     Note: This is experimental and due to be deprecated when it is
     replaced with the Tk DND.

The ‘tkinter.dnd’ module provides drag-and-drop support for objects
within a single application, within the same window or between windows.
To enable an object to be dragged, you must create an event binding for
it that starts the drag-and-drop process.  Typically, you bind a
ButtonPress event to a callback function that you write (see *note
Bindings and Events: 3fd4.).  The function should call *note
dnd_start(): 4046, where ‘source’ is the object to be dragged, and
‘event’ is the event that invoked the call (the argument to your
callback function).

Selection of a target object occurs as follows:

  1. Top-down search of area under mouse for target widget

        * Target widget should have a callable 'dnd_accept' attribute

        * If 'dnd_accept' is not present or returns ‘None’, search moves
          to parent widget

        * If no target widget is found, then the target object is ‘None’

  2. Call to '<old_target>.dnd_leave(source, event)'

  3. Call to '<new_target>.dnd_enter(source, event)'

  4. Call to '<target>.dnd_commit(source, event)' to notify of drop

  5. Call to '<source>.dnd_end(target, event)' to signal end of
     drag-and-drop

 -- Class: tkinter.dnd.DndHandler (source, event)

     The 'DndHandler' class handles drag-and-drop events tracking Motion
     and ButtonRelease events on the root of the event widget.

      -- Method: cancel (event=None)

          Cancel the drag-and-drop process.

      -- Method: finish (event, commit=0)

          Execute end of drag-and-drop functions.

      -- Method: on_motion (event)

          Inspect area below mouse for target objects while drag is
          performed.

      -- Method: on_release (event)

          Signal end of drag when the release pattern is triggered.

 -- Function: tkinter.dnd.dnd_start (source, event)

     Factory function for drag-and-drop process.

See also
........

*note Bindings and Events: 3fd4.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tkinter/dnd.py


File: python.info,  Node: tkinter ttk — Tk themed widgets,  Next: IDLE — Python editor and shell<2>,  Prev: tkinter dnd — Drag and drop support,  Up: Graphical user interfaces with Tk

5.25.8 ‘tkinter.ttk’ — Tk themed widgets
----------------------------------------

'Source code:' Lib/tkinter/ttk.py(1)

__________________________________________________________________

The ‘tkinter.ttk’ module provides access to the Tk themed widget set,
introduced in Tk 8.5.  It provides additional benefits including
anti-aliased font rendering under X11 and window transparency (requiring
a composition window manager on X11).

The basic idea for ‘tkinter.ttk’ is to separate, to the extent possible,
the code implementing a widget’s behavior from the code implementing its
appearance.

See also
........

Tk Widget Styling Support(2)

     A document introducing theming support for Tk

* Menu:

* Using Ttk::
* Ttk Widgets::
* Widget::
* Combobox::
* Spinbox::
* Notebook::
* Progressbar::
* Separator::
* Sizegrip::
* Treeview::
* Ttk Styling::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tkinter/ttk.py

   (2) https://core.tcl.tk/tips/doc/trunk/tip/48.md


File: python.info,  Node: Using Ttk,  Next: Ttk Widgets,  Up: tkinter ttk — Tk themed widgets

5.25.8.1 Using Ttk
..................

To start using Ttk, import its module:

     from tkinter import ttk

To override the basic Tk widgets, the import should follow the Tk
import:

     from tkinter import *
     from tkinter.ttk import *

That code causes several ‘tkinter.ttk’ widgets (‘Button’, ‘Checkbutton’,
‘Entry’, ‘Frame’, ‘Label’, ‘LabelFrame’, ‘Menubutton’, ‘PanedWindow’,
‘Radiobutton’, ‘Scale’ and ‘Scrollbar’) to automatically replace the Tk
widgets.

This has the direct benefit of using the new widgets which gives a
better look and feel across platforms; however, the replacement widgets
are not completely compatible.  The main difference is that widget
options such as “fg”, “bg” and others related to widget styling are no
longer present in Ttk widgets.  Instead, use the ‘ttk.Style’ class for
improved styling effects.

See also
........

Converting existing applications to use Tile widgets(1)

     A monograph (using Tcl terminology) about differences typically
     encountered when moving applications to use the new widgets.

   ---------- Footnotes ----------

   (1) https://tktable.sourceforge.net/tile/doc/converting.txt


File: python.info,  Node: Ttk Widgets,  Next: Widget,  Prev: Using Ttk,  Up: tkinter ttk — Tk themed widgets

5.25.8.2 Ttk Widgets
....................

Ttk comes with 18 widgets, twelve of which already existed in tkinter:
‘Button’, ‘Checkbutton’, ‘Entry’, ‘Frame’, ‘Label’, ‘LabelFrame’,
‘Menubutton’, ‘PanedWindow’, ‘Radiobutton’, ‘Scale’, ‘Scrollbar’, and
*note Spinbox: bb2.  The other six are new: *note Combobox: 4051, *note
Notebook: 4052, *note Progressbar: 4053, ‘Separator’, ‘Sizegrip’ and
*note Treeview: aa5.  And all them are subclasses of *note Widget: 4054.

Using the Ttk widgets gives the application an improved look and feel.
As discussed above, there are differences in how the styling is coded.

Tk code:

     l1 = tkinter.Label(text="Test", fg="black", bg="white")
     l2 = tkinter.Label(text="Test", fg="black", bg="white")

Ttk code:

     style = ttk.Style()
     style.configure("BW.TLabel", foreground="black", background="white")

     l1 = ttk.Label(text="Test", style="BW.TLabel")
     l2 = ttk.Label(text="Test", style="BW.TLabel")

For more information about *note TtkStyling: 4055, see the *note Style:
259. class documentation.


File: python.info,  Node: Widget,  Next: Combobox,  Prev: Ttk Widgets,  Up: tkinter ttk — Tk themed widgets

5.25.8.3 Widget
...............

‘ttk.Widget’ defines standard options and methods supported by Tk themed
widgets and is not supposed to be directly instantiated.

* Menu:

* Standard Options::
* Scrollable Widget Options::
* Label Options::
* Compatibility Options::
* Widget States::
* ttk.Widget: ttk Widget.


File: python.info,  Node: Standard Options,  Next: Scrollable Widget Options,  Up: Widget

5.25.8.4 Standard Options
.........................

All the ‘ttk’ Widgets accept the following options:

Option          Description
                
-----------------------------------------------------------------------------------
                
class           Specifies the window class.  The class is used when querying the
                option database for the window’s other options, to determine the
                default bindtags for the window, and to select the widget’s
                default layout and style.  This option is read-only, and may
                only be specified when the window is created.
                
                
cursor          Specifies the mouse cursor to be used for the widget.  If set to
                the empty string (the default), the cursor is inherited for the
                parent widget.
                
                
takefocus       Determines whether the window accepts the focus during keyboard
                traversal.  0, 1 or an empty string is returned.  If 0 is
                returned, it means that the window should be skipped entirely
                during keyboard traversal.  If 1, it means that the window
                should receive the input focus as long as it is viewable.  And
                an empty string means that the traversal scripts make the
                decision about whether or not to focus on the window.
                
                
style           May be used to specify a custom widget style.
                


File: python.info,  Node: Scrollable Widget Options,  Next: Label Options,  Prev: Standard Options,  Up: Widget

5.25.8.5 Scrollable Widget Options
..................................

The following options are supported by widgets that are controlled by a
scrollbar.

Option               Description
                     
-----------------------------------------------------------------------------------
                     
xscrollcommand       Used to communicate with horizontal scrollbars.
                     
                     When the view in the widget’s window change, the widget
                     will generate a Tcl command based on the scrollcommand.
                     
                     Usually this option consists of the method
                     ‘Scrollbar.set()’ of some scrollbar.  This will cause the
                     scrollbar to be updated whenever the view in the window
                     changes.
                     
                     
yscrollcommand       Used to communicate with vertical scrollbars.  For some
                     more information, see above.
                     


File: python.info,  Node: Label Options,  Next: Compatibility Options,  Prev: Scrollable Widget Options,  Up: Widget

5.25.8.6 Label Options
......................

The following options are supported by labels, buttons and other
button-like widgets.

Option             Description
                   
-----------------------------------------------------------------------------------
                   
text               Specifies a text string to be displayed inside the widget.
                   
                   
textvariable       Specifies a name whose value will be used in place of the
                   text option resource.
                   
                   
underline          If set, specifies the index (0-based) of a character to
                   underline in the text string.  The underline character is
                   used for mnemonic activation.
                   
                   
image              Specifies an image to display.  This is a list of 1 or more
                   elements.  The first element is the default image name.  The
                   rest of the list if a sequence of statespec/value pairs as
                   defined by *note Style.map(): 1a8d, specifying different
                   images to use when the widget is in a particular state or a
                   combination of states.  All images in the list should have
                   the same size.
                   
                   
compound           Specifies how to display the image relative to the text, in
                   the case both text and images options are present.  Valid
                   values are:
                   
                      * text: display text only
                   
                      * image: display image only
                   
                      * top, bottom, left, right: display image above, below,
                        left of, or right of the text, respectively.
                   
                      * none: the default.  display the image if present,
                        otherwise the text.
                   
                   
width              If greater than zero, specifies how much space, in character
                   widths, to allocate for the text label, if less than zero,
                   specifies a minimum width.  If zero or unspecified, the
                   natural width of the text label is used.
                   


File: python.info,  Node: Compatibility Options,  Next: Widget States,  Prev: Label Options,  Up: Widget

5.25.8.7 Compatibility Options
..............................

Option       Description
             
----------------------------------------------------------------------------------
             
state        May be set to “normal” or “disabled” to control the “disabled”
             state bit.  This is a write-only option: setting it changes the
             widget state, but the *note Widget.state(): 405b. method does not
             affect this option.
             


File: python.info,  Node: Widget States,  Next: ttk Widget,  Prev: Compatibility Options,  Up: Widget

5.25.8.8 Widget States
......................

The widget state is a bitmap of independent state flags.

Flag             Description
                 
-----------------------------------------------------------------------------------
                 
active           The mouse cursor is over the widget and pressing a mouse button
                 will cause some action to occur
                 
                 
disabled         Widget is disabled under program control
                 
                 
focus            Widget has keyboard focus
                 
                 
pressed          Widget is being pressed
                 
                 
selected         “On”, “true”, or “current” for things like Checkbuttons and
                 radiobuttons
                 
                 
background       Windows and Mac have a notion of an “active” or foreground
                 window.  The 'background' state is set for widgets in a
                 background window, and cleared for those in the foreground
                 window
                 
                 
readonly         Widget should not allow user modification
                 
                 
alternate        A widget-specific alternate display format
                 
                 
invalid          The widget’s value is invalid
                 

A state specification is a sequence of state names, optionally prefixed
with an exclamation point indicating that the bit is off.


File: python.info,  Node: ttk Widget,  Prev: Widget States,  Up: Widget

5.25.8.9 ttk.Widget
...................

Besides the methods described below, the ‘ttk.Widget’ supports the
methods ‘tkinter.Widget.cget()’ and ‘tkinter.Widget.configure()’.

 -- Class: tkinter.ttk.Widget

      -- Method: identify (x, y)

          Returns the name of the element at position 'x' 'y', or the
          empty string if the point does not lie within any element.

          'x' and 'y' are pixel coordinates relative to the widget.

      -- Method: instate (statespec, callback=None, *args, **kw)

          Test the widget’s state.  If a callback is not specified,
          returns ‘True’ if the widget state matches 'statespec' and
          ‘False’ otherwise.  If callback is specified then it is called
          with args if widget state matches 'statespec'.

      -- Method: state (statespec=None)

          Modify or inquire widget state.  If 'statespec' is specified,
          sets the widget state according to it and return a new
          'statespec' indicating which flags were changed.  If
          'statespec' is not specified, returns the currently enabled
          state flags.

     'statespec' will usually be a list or a tuple.


File: python.info,  Node: Combobox,  Next: Spinbox,  Prev: Widget,  Up: tkinter ttk — Tk themed widgets

5.25.8.10 Combobox
..................

The ‘ttk.Combobox’ widget combines a text field with a pop-down list of
values.  This widget is a subclass of ‘Entry’.

Besides the methods inherited from *note Widget: 4054.: ‘Widget.cget()’,
‘Widget.configure()’, *note Widget.identify(): 405e, *note
Widget.instate(): 405f. and *note Widget.state(): 405b, and the
following inherited from ‘Entry’: ‘Entry.bbox()’, ‘Entry.delete()’,
‘Entry.icursor()’, ‘Entry.index()’, ‘Entry.insert()’,
‘Entry.selection()’, ‘Entry.xview()’, it has some other methods,
described at ‘ttk.Combobox’.

* Menu:

* Options::
* Virtual events::
* ttk.Combobox: ttk Combobox.


File: python.info,  Node: Options,  Next: Virtual events,  Up: Combobox

5.25.8.11 Options
.................

This widget accepts the following specific options:

Option                Description
                      
-----------------------------------------------------------------------------------
                      
exportselection       Boolean value.  If set, the widget selection is linked to
                      the Window Manager selection (which can be returned by
                      invoking Misc.selection_get, for example).
                      
                      
justify               Specifies how the text is aligned within the widget.  One
                      of “left”, “center”, or “right”.
                      
                      
height                Specifies the height of the pop-down listbox, in rows.
                      
                      
postcommand           A script (possibly registered with Misc.register) that is
                      called immediately before displaying the values.  It may
                      specify which values to display.
                      
                      
state                 One of “normal”, “readonly”, or “disabled”.  In the
                      “readonly” state, the value may not be edited directly,
                      and the user can only selection of the values from the
                      dropdown list.  In the “normal” state, the text field is
                      directly editable.  In the “disabled” state, no
                      interaction is possible.
                      
                      
textvariable          Specifies a name whose value is linked to the widget
                      value.  Whenever the value associated with that name
                      changes, the widget value is updated, and vice versa.  See
                      ‘tkinter.StringVar’.
                      
                      
values                Specifies the list of values to display in the drop-down
                      listbox.
                      
                      
width                 Specifies an integer value indicating the desired width of
                      the entry window, in average-size characters of the
                      widget’s font.
                      


File: python.info,  Node: Virtual events,  Next: ttk Combobox,  Prev: Options,  Up: Combobox

5.25.8.12 Virtual events
........................

The combobox widgets generates a '<<ComboboxSelected>>' virtual event
when the user selects an element from the list of values.


File: python.info,  Node: ttk Combobox,  Prev: Virtual events,  Up: Combobox

5.25.8.13 ttk.Combobox
......................

 -- Class: tkinter.ttk.Combobox

      -- Method: current (newindex=None)

          If 'newindex' is specified, sets the combobox value to the
          element position 'newindex'.  Otherwise, returns the index of
          the current value or -1 if the current value is not in the
          values list.

      -- Method: get ()

          Returns the current value of the combobox.

      -- Method: set (value)

          Sets the value of the combobox to 'value'.


File: python.info,  Node: Spinbox,  Next: Notebook,  Prev: Combobox,  Up: tkinter ttk — Tk themed widgets

5.25.8.14 Spinbox
.................

The ‘ttk.Spinbox’ widget is a ‘ttk.Entry’ enhanced with increment and
decrement arrows.  It can be used for numbers or lists of string values.
This widget is a subclass of ‘Entry’.

Besides the methods inherited from *note Widget: 4054.: ‘Widget.cget()’,
‘Widget.configure()’, *note Widget.identify(): 405e, *note
Widget.instate(): 405f. and *note Widget.state(): 405b, and the
following inherited from ‘Entry’: ‘Entry.bbox()’, ‘Entry.delete()’,
‘Entry.icursor()’, ‘Entry.index()’, ‘Entry.insert()’, ‘Entry.xview()’,
it has some other methods, described at ‘ttk.Spinbox’.

* Menu:

* Options: Options<2>.
* Virtual events: Virtual events<2>.
* ttk.Spinbox: ttk Spinbox.


File: python.info,  Node: Options<2>,  Next: Virtual events<2>,  Up: Spinbox

5.25.8.15 Options
.................

This widget accepts the following specific options:

Option                     Description
                           
--------------------------------------------------------------------------------------
                           
from                       Float value.  If set, this is the minimum value to which
                           the decrement button will decrement.  Must be spelled as
                           ‘from_’ when used as an argument, since ‘from’ is a
                           Python keyword.
                           
                           
to                         Float value.  If set, this is the maximum value to which
                           the increment button will increment.
                           
                           
increment                  Float value.  Specifies the amount which the
                           increment/decrement buttons change the value.  Defaults
                           to 1.0.
                           
                           
values                     Sequence of string or float values.  If specified, the
                           increment/decrement buttons will cycle through the items
                           in this sequence rather than incrementing or
                           decrementing numbers.
                           
                           
wrap                       Boolean value.  If ‘True’, increment and decrement
                           buttons will cycle from the ‘to’ value to the ‘from’
                           value or the ‘from’ value to the ‘to’ value,
                           respectively.
                           
                           
format                     String value.  This specifies the format of numbers set
                           by the increment/decrement buttons.  It must be in the
                           form “%W.Pf”, where W is the padded width of the value,
                           P is the precision, and ‘%’ and ‘f’ are literal.
                           
                           
command                    Python callable.  Will be called with no arguments
                           whenever either of the increment or decrement buttons
                           are pressed.
                           


File: python.info,  Node: Virtual events<2>,  Next: ttk Spinbox,  Prev: Options<2>,  Up: Spinbox

5.25.8.16 Virtual events
........................

The spinbox widget generates an '<<Increment>>' virtual event when the
user presses <Up>, and a '<<Decrement>>' virtual event when the user
presses <Down>.


File: python.info,  Node: ttk Spinbox,  Prev: Virtual events<2>,  Up: Spinbox

5.25.8.17 ttk.Spinbox
.....................

 -- Class: tkinter.ttk.Spinbox

      -- Method: get ()

          Returns the current value of the spinbox.

      -- Method: set (value)

          Sets the value of the spinbox to 'value'.


File: python.info,  Node: Notebook,  Next: Progressbar,  Prev: Spinbox,  Up: tkinter ttk — Tk themed widgets

5.25.8.18 Notebook
..................

Ttk Notebook widget manages a collection of windows and displays a
single one at a time.  Each child window is associated with a tab, which
the user may select to change the currently displayed window.

* Menu:

* Options: Options<3>.
* Tab Options::
* Tab Identifiers::
* Virtual Events::
* ttk.Notebook: ttk Notebook.


File: python.info,  Node: Options<3>,  Next: Tab Options,  Up: Notebook

5.25.8.19 Options
.................

This widget accepts the following specific options:

Option        Description
              
-----------------------------------------------------------------------------------
              
height        If present and greater than zero, specifies the desired height of
              the pane area (not including internal padding or tabs).
              Otherwise, the maximum height of all panes is used.
              
              
padding       Specifies the amount of extra space to add around the outside of
              the notebook.  The padding is a list up to four length
              specifications left top right bottom.  If fewer than four elements
              are specified, bottom defaults to top, right defaults to left, and
              top defaults to left.
              
              
width         If present and greater than zero, specified the desired width of
              the pane area (not including internal padding).  Otherwise, the
              maximum width of all panes is used.
              


File: python.info,  Node: Tab Options,  Next: Tab Identifiers,  Prev: Options<3>,  Up: Notebook

5.25.8.20 Tab Options
.....................

There are also specific options for tabs:

Option          Description
                
-----------------------------------------------------------------------------------
                
state           Either “normal”, “disabled” or “hidden”.  If “disabled”, then
                the tab is not selectable.  If “hidden”, then the tab is not
                shown.
                
                
sticky          Specifies how the child window is positioned within the pane
                area.  Value is a string containing zero or more of the
                characters “n”, “s”, “e” or “w”.  Each letter refers to a side
                (north, south, east or west) that the child window will stick
                to, as per the ‘grid()’ geometry manager.
                
                
padding         Specifies the amount of extra space to add between the notebook
                and this pane.  Syntax is the same as for the option padding
                used by this widget.
                
                
text            Specifies a text to be displayed in the tab.
                
                
image           Specifies an image to display in the tab.  See the option image
                described in *note Widget: 4054.
                
                
compound        Specifies how to display the image relative to the text, in the
                case both options text and image are present.  See
                *note Label Options: 4059. for legal values.
                
                
underline       Specifies the index (0-based) of a character to underline in the
                text string.  The underlined character is used for mnemonic
                activation if *note Notebook.enable_traversal(): 4070. is
                called.
                


File: python.info,  Node: Tab Identifiers,  Next: Virtual Events,  Prev: Tab Options,  Up: Notebook

5.25.8.21 Tab Identifiers
.........................

The tab_id present in several methods of ‘ttk.Notebook’ may take any of
the following forms:

   * An integer between zero and the number of tabs

   * The name of a child window

   * A positional specification of the form “@x,y”, which identifies the
     tab

   * The literal string “current”, which identifies the currently
     selected tab

   * The literal string “end”, which returns the number of tabs (only
     valid for *note Notebook.index(): 4072.)


File: python.info,  Node: Virtual Events,  Next: ttk Notebook,  Prev: Tab Identifiers,  Up: Notebook

5.25.8.22 Virtual Events
........................

This widget generates a '<<NotebookTabChanged>>' virtual event after a
new tab is selected.


File: python.info,  Node: ttk Notebook,  Prev: Virtual Events,  Up: Notebook

5.25.8.23 ttk.Notebook
......................

 -- Class: tkinter.ttk.Notebook

      -- Method: add (child, **kw)

          Adds a new tab to the notebook.

          If window is currently managed by the notebook but hidden, it
          is restored to its previous position.

          See *note Tab Options: 406f. for the list of available
          options.

      -- Method: forget (tab_id)

          Removes the tab specified by 'tab_id', unmaps and unmanages
          the associated window.

      -- Method: hide (tab_id)

          Hides the tab specified by 'tab_id'.

          The tab will not be displayed, but the associated window
          remains managed by the notebook and its configuration
          remembered.  Hidden tabs may be restored with the *note add():
          4075. command.

      -- Method: identify (x, y)

          Returns the name of the tab element at position 'x', 'y', or
          the empty string if none.

      -- Method: index (tab_id)

          Returns the numeric index of the tab specified by 'tab_id', or
          the total number of tabs if 'tab_id' is the string “end”.

      -- Method: insert (pos, child, **kw)

          Inserts a pane at the specified position.

          'pos' is either the string “end”, an integer index, or the
          name of a managed child.  If 'child' is already managed by the
          notebook, moves it to the specified position.

          See *note Tab Options: 406f. for the list of available
          options.

      -- Method: select (tab_id=None)

          Selects the specified 'tab_id'.

          The associated child window will be displayed, and the
          previously selected window (if different) is unmapped.  If
          'tab_id' is omitted, returns the widget name of the currently
          selected pane.

      -- Method: tab (tab_id, option=None, **kw)

          Query or modify the options of the specific 'tab_id'.

          If 'kw' is not given, returns a dictionary of the tab option
          values.  If 'option' is specified, returns the value of that
          'option'.  Otherwise, sets the options to the corresponding
          values.

      -- Method: tabs ()

          Returns a list of windows managed by the notebook.

      -- Method: enable_traversal ()

          Enable keyboard traversal for a toplevel window containing
          this notebook.

          This will extend the bindings for the toplevel window
          containing the notebook as follows:

             * ‘Control’-‘Tab’: selects the tab following the currently
               selected one.

             * ‘Shift’-‘Control’-‘Tab’: selects the tab preceding the
               currently selected one.

             * ‘Alt’-‘K’: where 'K' is the mnemonic (underlined)
               character of any tab, will select that tab.

          Multiple notebooks in a single toplevel may be enabled for
          traversal, including nested notebooks.  However, notebook
          traversal only works properly if all panes have the notebook
          they are in as master.


File: python.info,  Node: Progressbar,  Next: Separator,  Prev: Notebook,  Up: tkinter ttk — Tk themed widgets

5.25.8.24 Progressbar
.....................

The ‘ttk.Progressbar’ widget shows the status of a long-running
operation.  It can operate in two modes: 1) the determinate mode which
shows the amount completed relative to the total amount of work to be
done and 2) the indeterminate mode which provides an animated display to
let the user know that work is progressing.

* Menu:

* Options: Options<4>.
* ttk.Progressbar: ttk Progressbar.


File: python.info,  Node: Options<4>,  Next: ttk Progressbar,  Up: Progressbar

5.25.8.25 Options
.................

This widget accepts the following specific options:

Option         Description
               
-----------------------------------------------------------------------------------
               
orient         One of “horizontal” or “vertical”.  Specifies the orientation of
               the progress bar.
               
               
length         Specifies the length of the long axis of the progress bar (width
               if horizontal, height if vertical).
               
               
mode           One of “determinate” or “indeterminate”.
               
               
maximum        A number specifying the maximum value.  Defaults to 100.
               
               
value          The current value of the progress bar.  In “determinate” mode,
               this represents the amount of work completed.  In “indeterminate”
               mode, it is interpreted as modulo 'maximum'; that is, the
               progress bar completes one “cycle” when its value increases by
               'maximum'.
               
               
variable       A name which is linked to the option value.  If specified, the
               value of the progress bar is automatically set to the value of
               this name whenever the latter is modified.
               
               
phase          Read-only option.  The widget periodically increments the value
               of this option whenever its value is greater than 0 and, in
               determinate mode, less than maximum.  This option may be used by
               the current theme to provide additional animation effects.
               


File: python.info,  Node: ttk Progressbar,  Prev: Options<4>,  Up: Progressbar

5.25.8.26 ttk.Progressbar
.........................

 -- Class: tkinter.ttk.Progressbar

      -- Method: start (interval=None)

          Begin autoincrement mode: schedules a recurring timer event
          that calls *note Progressbar.step(): 4081. every 'interval'
          milliseconds.  If omitted, 'interval' defaults to 50
          milliseconds.

      -- Method: step (amount=None)

          Increments the progress bar’s value by 'amount'.

          'amount' defaults to 1.0 if omitted.

      -- Method: stop ()

          Stop autoincrement mode: cancels any recurring timer event
          initiated by *note Progressbar.start(): 4080. for this
          progress bar.


File: python.info,  Node: Separator,  Next: Sizegrip,  Prev: Progressbar,  Up: tkinter ttk — Tk themed widgets

5.25.8.27 Separator
...................

The ‘ttk.Separator’ widget displays a horizontal or vertical separator
bar.

It has no other methods besides the ones inherited from ‘ttk.Widget’.

* Menu:

* Options: Options<5>.


File: python.info,  Node: Options<5>,  Up: Separator

5.25.8.28 Options
.................

This widget accepts the following specific option:

Option       Description
             
----------------------------------------------------------------------------------
             
orient       One of “horizontal” or “vertical”.  Specifies the orientation of
             the separator.
             


File: python.info,  Node: Sizegrip,  Next: Treeview,  Prev: Separator,  Up: tkinter ttk — Tk themed widgets

5.25.8.29 Sizegrip
..................

The ‘ttk.Sizegrip’ widget (also known as a grow box) allows the user to
resize the containing toplevel window by pressing and dragging the grip.

This widget has neither specific options nor specific methods, besides
the ones inherited from ‘ttk.Widget’.

* Menu:

* Platform-specific notes::
* Bugs::


File: python.info,  Node: Platform-specific notes,  Next: Bugs,  Up: Sizegrip

5.25.8.30 Platform-specific notes
.................................

   * On macOS, toplevel windows automatically include a built-in size
     grip by default.  Adding a ‘Sizegrip’ is harmless, since the
     built-in grip will just mask the widget.


File: python.info,  Node: Bugs,  Prev: Platform-specific notes,  Up: Sizegrip

5.25.8.31 Bugs
..............

   * If the containing toplevel’s position was specified relative to the
     right or bottom of the screen (e.g.  ….), the ‘Sizegrip’ widget
     will not resize the window.

   * This widget supports only “southeast” resizing.


File: python.info,  Node: Treeview,  Next: Ttk Styling,  Prev: Sizegrip,  Up: tkinter ttk — Tk themed widgets

5.25.8.32 Treeview
..................

The ‘ttk.Treeview’ widget displays a hierarchical collection of items.
Each item has a textual label, an optional image, and an optional list
of data values.  The data values are displayed in successive columns
after the tree label.

The order in which data values are displayed may be controlled by
setting the widget option ‘displaycolumns’.  The tree widget can also
display column headings.  Columns may be accessed by number or symbolic
names listed in the widget option columns.  See *note Column
Identifiers: 4089.

Each item is identified by a unique name.  The widget will generate item
IDs if they are not supplied by the caller.  There is a distinguished
root item, named ‘{}’.  The root item itself is not displayed; its
children appear at the top level of the hierarchy.

Each item also has a list of tags, which can be used to associate event
bindings with individual items and control the appearance of the item.

The Treeview widget supports horizontal and vertical scrolling,
according to the options described in *note Scrollable Widget Options:
4058. and the methods *note Treeview.xview(): 408a. and *note
Treeview.yview(): 408b.

* Menu:

* Options: Options<6>.
* Item Options::
* Tag Options::
* Column Identifiers::
* Virtual Events: Virtual Events<2>.
* ttk.Treeview: ttk Treeview.


File: python.info,  Node: Options<6>,  Next: Item Options,  Up: Treeview

5.25.8.33 Options
.................

This widget accepts the following specific options:

Option               Description
                     
----------------------------------------------------------------------------------
                     
columns              A list of column identifiers, specifying the number of
                     columns and their names.
                     
                     
displaycolumns       A list of column identifiers (either symbolic or integer
                     indices) specifying which data columns are displayed and
                     the order in which they appear, or the string “#all”.
                     
                     
height               Specifies the number of rows which should be visible.
                     Note: the requested width is determined from the sum of
                     the column widths.
                     
                     
padding              Specifies the internal padding for the widget.  The
                     padding is a list of up to four length specifications.
                     
                     
selectmode           Controls how the built-in class bindings manage the
                     selection.  One of “extended”, “browse” or “none”.  If set
                     to “extended” (the default), multiple items may be
                     selected.  If “browse”, only a single item will be
                     selected at a time.  If “none”, the selection will not be
                     changed.
                     
                     Note that the application code and tag bindings can set
                     the selection however they wish, regardless of the value
                     of this option.
                     
                     
show                 A list containing zero or more of the following values,
                     specifying which elements of the tree to display.
                     
                        * tree: display tree labels in column #0.
                     
                        * headings: display the heading row.
                     
                     The default is “tree headings”, i.e., show all elements.
                     
                     'Note': Column #0 always refers to the tree column, even
                     if show=”tree” is not specified.
                     


File: python.info,  Node: Item Options,  Next: Tag Options,  Prev: Options<6>,  Up: Treeview

5.25.8.34 Item Options
......................

The following item options may be specified for items in the insert and
item widget commands.

Option       Description
             
---------------------------------------------------------------------------------
             
text         The textual label to display for the item.
             
             
image        A Tk Image, displayed to the left of the label.
             
             
values       The list of values associated with the item.
             
             Each item should have the same number of values as the widget
             option columns.  If there are fewer values than columns, the
             remaining values are assumed empty.  If there are more values
             than columns, the extra values are ignored.
             
             
open         ‘True’/‘False’ value indicating whether the item’s children
             should be displayed or hidden.
             
             
tags         A list of tags associated with this item.
             


File: python.info,  Node: Tag Options,  Next: Column Identifiers,  Prev: Item Options,  Up: Treeview

5.25.8.35 Tag Options
.....................

The following options may be specified on tags:

Option           Description
                 
---------------------------------------------------------------------------------
                 
foreground       Specifies the text foreground color.
                 
                 
background       Specifies the cell or item background color.
                 
                 
font             Specifies the font to use when drawing text.
                 
                 
image            Specifies the item image, in case the item’s image option is
                 empty.
                 


File: python.info,  Node: Column Identifiers,  Next: Virtual Events<2>,  Prev: Tag Options,  Up: Treeview

5.25.8.36 Column Identifiers
............................

Column identifiers take any of the following forms:

   * A symbolic name from the list of columns option.

   * An integer n, specifying the nth data column.

   * A string of the form #n, where n is an integer, specifying the nth
     display column.

Notes:

   * Item’s option values may be displayed in a different order than the
     order in which they are stored.

   * Column #0 always refers to the tree column, even if show=”tree” is
     not specified.

A data column number is an index into an item’s option values list; a
display column number is the column number in the tree where the values
are displayed.  Tree labels are displayed in column #0.  If option
displaycolumns is not set, then data column n is displayed in column
#n+1.  Again, 'column #0 always refers to the tree column'.


File: python.info,  Node: Virtual Events<2>,  Next: ttk Treeview,  Prev: Column Identifiers,  Up: Treeview

5.25.8.37 Virtual Events
........................

The Treeview widget generates the following virtual events.

Event                    Description
                         
--------------------------------------------------------------------------------
                         
<<TreeviewSelect>>       Generated whenever the selection changes.
                         
                         
<<TreeviewOpen>>         Generated just before settings the focus item to
                         open=True.
                         
                         
<<TreeviewClose>>        Generated just after setting the focus item to
                         open=False.
                         

The *note Treeview.focus(): 4090. and *note Treeview.selection(): aa4.
methods can be used to determine the affected item or items.


File: python.info,  Node: ttk Treeview,  Prev: Virtual Events<2>,  Up: Treeview

5.25.8.38 ttk.Treeview
......................

 -- Class: tkinter.ttk.Treeview

      -- Method: bbox (item, column=None)

          Returns the bounding box (relative to the treeview widget’s
          window) of the specified 'item' in the form (x, y, width,
          height).

          If 'column' is specified, returns the bounding box of that
          cell.  If the 'item' is not visible (i.e., if it is a
          descendant of a closed item or is scrolled offscreen), returns
          an empty string.

      -- Method: get_children (item=None)

          Returns the list of children belonging to 'item'.

          If 'item' is not specified, returns root children.

      -- Method: set_children (item, *newchildren)

          Replaces 'item'’s child with 'newchildren'.

          Children present in 'item' that are not present in
          'newchildren' are detached from the tree.  No items in
          'newchildren' may be an ancestor of 'item'.  Note that not
          specifying 'newchildren' results in detaching 'item'’s
          children.

      -- Method: column (column, option=None, **kw)

          Query or modify the options for the specified 'column'.

          If 'kw' is not given, returns a dict of the column option
          values.  If 'option' is specified then the value for that
          'option' is returned.  Otherwise, sets the options to the
          corresponding values.

          The valid options/values are:

          'id'

               Returns the column name.  This is a read-only option.

          'anchor': One of the standard Tk anchor values.

               Specifies how the text in this column should be aligned
               with respect to the cell.

          'minwidth': width

               The minimum width of the column in pixels.  The treeview
               widget will not make the column any smaller than
               specified by this option when the widget is resized or
               the user drags a column.

          'stretch': ‘True’/‘False’

               Specifies whether the column’s width should be adjusted
               when the widget is resized.

          'width': width

               The width of the column in pixels.

          To configure the tree column, call this with column = “#0”

      -- Method: delete (*items)

          Delete all specified 'items' and all their descendants.

          The root item may not be deleted.

      -- Method: detach (*items)

          Unlinks all of the specified 'items' from the tree.

          The items and all of their descendants are still present, and
          may be reinserted at another point in the tree, but will not
          be displayed.

          The root item may not be detached.

      -- Method: exists (item)

          Returns ‘True’ if the specified 'item' is present in the tree.

      -- Method: focus (item=None)

          If 'item' is specified, sets the focus item to 'item'.
          Otherwise, returns the current focus item, or ‘’ if there is
          none.

      -- Method: heading (column, option=None, **kw)

          Query or modify the heading options for the specified
          'column'.

          If 'kw' is not given, returns a dict of the heading option
          values.  If 'option' is specified then the value for that
          'option' is returned.  Otherwise, sets the options to the
          corresponding values.

          The valid options/values are:

          'text': text

               The text to display in the column heading.

          'image': imageName

               Specifies an image to display to the right of the column
               heading.

          'anchor': anchor

               Specifies how the heading text should be aligned.  One of
               the standard Tk anchor values.

          'command': callback

               A callback to be invoked when the heading label is
               pressed.

          To configure the tree column heading, call this with column =
          “#0”.

      -- Method: identify (component, x, y)

          Returns a description of the specified 'component' under the
          point given by 'x' and 'y', or the empty string if no such
          'component' is present at that position.

      -- Method: identify_row (y)

          Returns the item ID of the item at position 'y'.

      -- Method: identify_column (x)

          Returns the data column identifier of the cell at position
          'x'.

          The tree column has ID #0.

      -- Method: identify_region (x, y)

          Returns one of:

          region          meaning
                          
          -----------------------------------------------------------
                          
          heading         Tree heading area.
                          
                          
          separator       Space between two columns headings.
                          
                          
          tree            The tree area.
                          
                          
          cell            A data cell.
                          

          Availability: Tk 8.6.

      -- Method: identify_element (x, y)

          Returns the element at position 'x', 'y'.

          Availability: Tk 8.6.

      -- Method: index (item)

          Returns the integer index of 'item' within its parent’s list
          of children.

      -- Method: insert (parent, index, iid=None, **kw)

          Creates a new item and returns the item identifier of the
          newly created item.

          'parent' is the item ID of the parent item, or the empty
          string to create a new top-level item.  'index' is an integer,
          or the value “end”, specifying where in the list of parent’s
          children to insert the new item.  If 'index' is less than or
          equal to zero, the new node is inserted at the beginning; if
          'index' is greater than or equal to the current number of
          children, it is inserted at the end.  If 'iid' is specified,
          it is used as the item identifier; 'iid' must not already
          exist in the tree.  Otherwise, a new unique identifier is
          generated.

          See *note Item Options: 408d. for the list of available
          options.

      -- Method: item (item, option=None, **kw)

          Query or modify the options for the specified 'item'.

          If no options are given, a dict with options/values for the
          item is returned.  If 'option' is specified then the value for
          that option is returned.  Otherwise, sets the options to the
          corresponding values as given by 'kw'.

      -- Method: move (item, parent, index)

          Moves 'item' to position 'index' in 'parent'’s list of
          children.

          It is illegal to move an item under one of its descendants.
          If 'index' is less than or equal to zero, 'item' is moved to
          the beginning; if greater than or equal to the number of
          children, it is moved to the end.  If 'item' was detached it
          is reattached.

      -- Method: next (item)

          Returns the identifier of 'item'’s next sibling, or ‘’ if
          'item' is the last child of its parent.

      -- Method: parent (item)

          Returns the ID of the parent of 'item', or ‘’ if 'item' is at
          the top level of the hierarchy.

      -- Method: prev (item)

          Returns the identifier of 'item'’s previous sibling, or ‘’ if
          'item' is the first child of its parent.

      -- Method: reattach (item, parent, index)

          An alias for *note Treeview.move(): 40a2.

      -- Method: see (item)

          Ensure that 'item' is visible.

          Sets all of 'item'’s ancestors open option to ‘True’, and
          scrolls the widget if necessary so that 'item' is within the
          visible portion of the tree.

      -- Method: selection ()

          Returns a tuple of selected items.

          Changed in version 3.8: ‘selection()’ no longer takes
          arguments.  For changing the selection state use the following
          selection methods.

      -- Method: selection_set (*items)

          'items' becomes the new selection.

          Changed in version 3.6: 'items' can be passed as separate
          arguments, not just as a single tuple.

      -- Method: selection_add (*items)

          Add 'items' to the selection.

          Changed in version 3.6: 'items' can be passed as separate
          arguments, not just as a single tuple.

      -- Method: selection_remove (*items)

          Remove 'items' from the selection.

          Changed in version 3.6: 'items' can be passed as separate
          arguments, not just as a single tuple.

      -- Method: selection_toggle (*items)

          Toggle the selection state of each item in 'items'.

          Changed in version 3.6: 'items' can be passed as separate
          arguments, not just as a single tuple.

      -- Method: set (item, column=None, value=None)

          With one argument, returns a dictionary of column/value pairs
          for the specified 'item'.  With two arguments, returns the
          current value of the specified 'column'.  With three
          arguments, sets the value of given 'column' in given 'item' to
          the specified 'value'.

      -- Method: tag_bind (tagname, sequence=None, callback=None)

          Bind a callback for the given event 'sequence' to the tag
          'tagname'.  When an event is delivered to an item, the
          callbacks for each of the item’s tags option are called.

      -- Method: tag_configure (tagname, option=None, **kw)

          Query or modify the options for the specified 'tagname'.

          If 'kw' is not given, returns a dict of the option settings
          for 'tagname'.  If 'option' is specified, returns the value
          for that 'option' for the specified 'tagname'.  Otherwise,
          sets the options to the corresponding values for the given
          'tagname'.

      -- Method: tag_has (tagname, item=None)

          If 'item' is specified, returns 1 or 0 depending on whether
          the specified 'item' has the given 'tagname'.  Otherwise,
          returns a list of all items that have the specified tag.

          Availability: Tk 8.6

      -- Method: xview (*args)

          Query or modify horizontal position of the treeview.

      -- Method: yview (*args)

          Query or modify vertical position of the treeview.


File: python.info,  Node: Ttk Styling,  Prev: Treeview,  Up: tkinter ttk — Tk themed widgets

5.25.8.39 Ttk Styling
.....................

Each widget in ‘ttk’ is assigned a style, which specifies the set of
elements making up the widget and how they are arranged, along with
dynamic and default settings for element options.  By default the style
name is the same as the widget’s class name, but it may be overridden by
the widget’s style option.  If you don’t know the class name of a
widget, use the method ‘Misc.winfo_class()’ (somewidget.winfo_class()).

See also
........

Tcl'2004 conference presentation(1)

     This document explains how the theme engine works

 -- Class: tkinter.ttk.Style

     This class is used to manipulate the style database.

      -- Method: configure (style, query_opt=None, **kw)

          Query or set the default value of the specified option(s) in
          'style'.

          Each key in 'kw' is an option and each value is a string
          identifying the value for that option.

          For example, to change every default button to be a flat
          button with some padding and a different background color:

               from tkinter import ttk
               import tkinter

               root = tkinter.Tk()

               ttk.Style().configure("TButton", padding=6, relief="flat",
                  background="#ccc")

               btn = ttk.Button(text="Sample")
               btn.pack()

               root.mainloop()

      -- Method: map (style, query_opt=None, **kw)

          Query or sets dynamic values of the specified option(s) in
          'style'.

          Each key in 'kw' is an option and each value should be a list
          or a tuple (usually) containing statespecs grouped in tuples,
          lists, or some other preference.  A statespec is a compound of
          one or more states and then a value.

          An example may make it more understandable:

               import tkinter
               from tkinter import ttk

               root = tkinter.Tk()

               style = ttk.Style()
               style.map("C.TButton",
                   foreground=[('pressed', 'red'), ('active', 'blue')],
                   background=[('pressed', '!disabled', 'black'), ('active', 'white')]
                   )

               colored_btn = ttk.Button(text="Test", style="C.TButton").pack()

               root.mainloop()

          Note that the order of the (states, value) sequences for an
          option does matter, if the order is changed to ‘[('active',
          'blue'), ('pressed', 'red')]’ in the foreground option, for
          example, the result would be a blue foreground when the widget
          were in active or pressed states.

      -- Method: lookup (style, option, state=None, default=None)

          Returns the value specified for 'option' in 'style'.

          If 'state' is specified, it is expected to be a sequence of
          one or more states.  If the 'default' argument is set, it is
          used as a fallback value in case no specification for option
          is found.

          To check what font a Button uses by default:

               from tkinter import ttk

               print(ttk.Style().lookup("TButton", "font"))

      -- Method: layout (style, layoutspec=None)

          Define the widget layout for given 'style'.  If 'layoutspec'
          is omitted, return the layout specification for given style.

          'layoutspec', if specified, is expected to be a list or some
          other sequence type (excluding strings), where each item
          should be a tuple and the first item is the layout name and
          the second item should have the format described in *note
          Layouts: 40b3.

          To understand the format, see the following example (it is not
          intended to do anything useful):

               from tkinter import ttk
               import tkinter

               root = tkinter.Tk()

               style = ttk.Style()
               style.layout("TMenubutton", [
                  ("Menubutton.background", None),
                  ("Menubutton.button", {"children":
                      [("Menubutton.focus", {"children":
                          [("Menubutton.padding", {"children":
                              [("Menubutton.label", {"side": "left", "expand": 1})]
                          })]
                      })]
                  }),
               ])

               mbtn = ttk.Menubutton(text='Text')
               mbtn.pack()
               root.mainloop()

      -- Method: element_create (elementname, etype, *args, **kw)

          Create a new element in the current theme, of the given
          'etype' which is expected to be either “image”, “from” or
          “vsapi”.  The latter is only available in Tk 8.6 on Windows.

          If “image” is used, 'args' should contain the default image
          name followed by statespec/value pairs (this is the
          imagespec), and 'kw' may have the following options:

          border=padding

               padding is a list of up to four integers, specifying the
               left, top, right, and bottom borders, respectively.

          height=height

               Specifies a minimum height for the element.  If less than
               zero, the base image’s height is used as a default.

          padding=padding

               Specifies the element’s interior padding.  Defaults to
               border’s value if not specified.

          sticky=spec

               Specifies how the image is placed within the final
               parcel.  spec contains zero or more characters “n”, “s”,
               “w”, or “e”.

          width=width

               Specifies a minimum width for the element.  If less than
               zero, the base image’s width is used as a default.

          Example:

               img1 = tkinter.PhotoImage(master=root, file='button.png')
               img1 = tkinter.PhotoImage(master=root, file='button-pressed.png')
               img1 = tkinter.PhotoImage(master=root, file='button-active.png')
               style = ttk.Style(root)
               style.element_create('Button.button', 'image',
                                    img1, ('pressed', img2), ('active', img3),
                                    border=(2, 4), sticky='we')

          If “from” is used as the value of 'etype', ‘element_create()’
          will clone an existing element.  'args' is expected to contain
          a themename, from which the element will be cloned, and
          optionally an element to clone from.  If this element to clone
          from is not specified, an empty element will be used.  'kw' is
          discarded.

          Example:

               style = ttk.Style(root)
               style.element_create('plain.background', 'from', 'default')

          If “vsapi” is used as the value of 'etype', ‘element_create()’
          will create a new element in the current theme whose visual
          appearance is drawn using the Microsoft Visual Styles API
          which is responsible for the themed styles on Windows XP and
          Vista.  'args' is expected to contain the Visual Styles class
          and part as given in the Microsoft documentation followed by
          an optional sequence of tuples of ttk states and the
          corresponding Visual Styles API state value.  'kw' may have
          the following options:

          padding=padding

               Specify the element’s interior padding.  'padding' is a
               list of up to four integers specifying the left, top,
               right and bottom padding quantities respectively.  If
               fewer than four elements are specified, bottom defaults
               to top, right defaults to left, and top defaults to left.
               In other words, a list of three numbers specify the left,
               vertical, and right padding; a list of two numbers
               specify the horizontal and the vertical padding; a single
               number specifies the same padding all the way around the
               widget.  This option may not be mixed with any other
               options.

          margins=padding

               Specifies the elements exterior padding.  'padding' is a
               list of up to four integers specifying the left, top,
               right and bottom padding quantities respectively.  This
               option may not be mixed with any other options.

          width=width

               Specifies the width for the element.  If this option is
               set then the Visual Styles API will not be queried for
               the recommended size or the part.  If this option is set
               then 'height' should also be set.  The 'width' and
               'height' options cannot be mixed with the 'padding' or
               'margins' options.

          height=height

               Specifies the height of the element.  See the comments
               for 'width'.

          Example:

               style = ttk.Style(root)
               style.element_create('pin', 'vsapi', 'EXPLORERBAR', 3, [
                                    ('pressed', '!selected', 3),
                                    ('active', '!selected', 2),
                                    ('pressed', 'selected', 6),
                                    ('active', 'selected', 5),
                                    ('selected', 4),
                                    ('', 1)])
               style.layout('Explorer.Pin',
                            [('Explorer.Pin.pin', {'sticky': 'news'})])
               pin = ttk.Checkbutton(style='Explorer.Pin')
               pin.pack(expand=True, fill='both')

          Changed in version 3.13: Added support of the “vsapi” element
          factory.

      -- Method: element_names ()

          Returns the list of elements defined in the current theme.

      -- Method: element_options (elementname)

          Returns the list of 'elementname'’s options.

      -- Method: theme_create (themename, parent=None, settings=None)

          Create a new theme.

          It is an error if 'themename' already exists.  If 'parent' is
          specified, the new theme will inherit styles, elements and
          layouts from the parent theme.  If 'settings' are present they
          are expected to have the same syntax used for *note
          theme_settings(): 40b7.

      -- Method: theme_settings (themename, settings)

          Temporarily sets the current theme to 'themename', apply
          specified 'settings' and then restore the previous theme.

          Each key in 'settings' is a style and each value may contain
          the keys ‘configure’, ‘map’, ‘layout’ and ‘element create’ and
          they are expected to have the same format as specified by the
          methods *note Style.configure(): 40b0, *note Style.map():
          1a8d, *note Style.layout(): 40b2. and *note
          Style.element_create(): 258. respectively.

          As an example, let’s change the Combobox for the default theme
          a bit:

               from tkinter import ttk
               import tkinter

               root = tkinter.Tk()

               style = ttk.Style()
               style.theme_settings("default", {
                  "TCombobox": {
                      "configure": {"padding": 5},
                      "map": {
                          "background": [("active", "green2"),
                                         ("!disabled", "green4")],
                          "fieldbackground": [("!disabled", "green3")],
                          "foreground": [("focus", "OliveDrab1"),
                                         ("!disabled", "OliveDrab2")]
                      }
                  }
               })

               combo = ttk.Combobox().pack()

               root.mainloop()

      -- Method: theme_names ()

          Returns a list of all known themes.

      -- Method: theme_use (themename=None)

          If 'themename' is not given, returns the theme in use.
          Otherwise, sets the current theme to 'themename', refreshes
          all widgets and emits a <<ThemeChanged>> event.

* Menu:

* Layouts::

   ---------- Footnotes ----------

   (1) https://tktable.sourceforge.net/tile/tile-tcl2004.pdf


File: python.info,  Node: Layouts,  Up: Ttk Styling

5.25.8.40 Layouts
.................

A layout can be just ‘None’, if it takes no options, or a dict of
options specifying how to arrange the element.  The layout mechanism
uses a simplified version of the pack geometry manager: given an initial
cavity, each element is allocated a parcel.

The valid options/values are:

'side': whichside

     Specifies which side of the cavity to place the element; one of
     top, right, bottom or left.  If omitted, the element occupies the
     entire cavity.

'sticky': nswe

     Specifies where the element is placed inside its allocated parcel.

'unit': 0 or 1

     If set to 1, causes the element and all of its descendants to be
     treated as a single element for the purposes of *note
     Widget.identify(): 405e. et al.  It’s used for things like
     scrollbar thumbs with grips.

'children': [sublayout… ]

     Specifies a list of elements to place inside the element.  Each
     element is a tuple (or other sequence type) where the first item is
     the layout name, and the other is a *note Layout: 40b3.


File: python.info,  Node: IDLE — Python editor and shell<2>,  Next: turtle — Turtle graphics,  Prev: tkinter ttk — Tk themed widgets,  Up: Graphical user interfaces with Tk

5.25.9 IDLE — Python editor and shell
-------------------------------------

'Source code:' Lib/idlelib/(1)

__________________________________________________________________

IDLE is Python’s Integrated Development and Learning Environment.

IDLE has the following features:

   * cross-platform: works mostly the same on Windows, Unix, and macOS

   * Python shell window (interactive interpreter) with colorizing of
     code input, output, and error messages

   * multi-window text editor with multiple undo, Python colorizing,
     smart indent, call tips, auto completion, and other features

   * search within any window, replace within editor windows, and search
     through multiple files (grep)

   * debugger with persistent breakpoints, stepping, and viewing of
     global and local namespaces

   * configuration, browsers, and other dialogs

The IDLE application is implemented in the *note idlelib: 73. package.

This is an optional module.  If it is missing from your copy of CPython,
look for documentation from your distributor (that is, whoever provided
Python to you).  If you are the distributor, see Requirements for
optional modules.

* Menu:

* Menus::
* Editing and Navigation::
* Startup and Code Execution::
* Help and Preferences::
* idlelib — implementation of IDLE application::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/idlelib/


File: python.info,  Node: Menus,  Next: Editing and Navigation,  Up: IDLE — Python editor and shell<2>

5.25.9.1 Menus
..............

IDLE has two main window types, the Shell window and the Editor window.
It is possible to have multiple editor windows simultaneously.  On
Windows and Linux, each has its own top menu.  Each menu documented
below indicates which window type it is associated with.

Output windows, such as used for Edit => Find in Files, are a subtype of
editor window.  They currently have the same top menu but a different
default title and context menu.

On macOS, there is one application menu.  It dynamically changes
according to the window currently selected.  It has an IDLE menu, and
some entries described below are moved around to conform to Apple
guidelines.

* Menu:

* File menu (Shell and Editor): File menu Shell and Editor.
* Edit menu (Shell and Editor): Edit menu Shell and Editor.
* Format menu (Editor window only): Format menu Editor window only.
* Run menu (Editor window only): Run menu Editor window only.
* Shell menu (Shell window only): Shell menu Shell window only.
* Debug menu (Shell window only): Debug menu Shell window only.
* Options menu (Shell and Editor): Options menu Shell and Editor.
* Window menu (Shell and Editor): Window menu Shell and Editor.
* Help menu (Shell and Editor): Help menu Shell and Editor.
* Context menus::


File: python.info,  Node: File menu Shell and Editor,  Next: Edit menu Shell and Editor,  Up: Menus

5.25.9.2 File menu (Shell and Editor)
.....................................

New File

     Create a new file editing window.

Open…

     Open an existing file with an Open dialog.

Open Module…

     Open an existing module (searches sys.path).

Recent Files

     Open a list of recent files.  Click one to open it.

Module Browser

     Show functions, classes, and methods in the current Editor file in
     a tree structure.  In the shell, open a module first.

Path Browser

     Show sys.path directories, modules, functions, classes and methods
     in a tree structure.

Save

     Save the current window to the associated file, if there is one.
     Windows that have been changed since being opened or last saved
     have a * before and after the window title.  If there is no
     associated file, do Save As instead.

Save As…

     Save the current window with a Save As dialog.  The file saved
     becomes the new associated file for the window.  (If your file
     manager is set to hide extensions, the current extension will be
     omitted in the file name box.  If the new filename has no ‘.’,
     ‘.py’ and ‘.txt’ will be added for Python and text files, except
     that on macOS Aqua,’.py’ is added for all files.)

Save Copy As…

     Save the current window to different file without changing the
     associated file.  (See Save As note above about filename
     extensions.)

Print Window

     Print the current window to the default printer.

Close Window

     Close the current window (if an unsaved editor, ask to save; if an
     unsaved Shell, ask to quit execution).  Calling ‘exit()’ or
     ‘close()’ in the Shell window also closes Shell.  If this is the
     only window, also exit IDLE.

Exit IDLE

     Close all windows and quit IDLE (ask to save unsaved edit windows).


File: python.info,  Node: Edit menu Shell and Editor,  Next: Format menu Editor window only,  Prev: File menu Shell and Editor,  Up: Menus

5.25.9.3 Edit menu (Shell and Editor)
.....................................

Undo

     Undo the last change to the current window.  A maximum of 1000
     changes may be undone.

Redo

     Redo the last undone change to the current window.

Select All

     Select the entire contents of the current window.

Cut

     Copy selection into the system-wide clipboard; then delete the
     selection.

Copy

     Copy selection into the system-wide clipboard.

Paste

     Insert contents of the system-wide clipboard into the current
     window.

The clipboard functions are also available in context menus.

Find…

     Open a search dialog with many options

Find Again

     Repeat the last search, if there is one.

Find Selection

     Search for the currently selected string, if there is one.

Find in Files…

     Open a file search dialog.  Put results in a new output window.

Replace…

     Open a search-and-replace dialog.

Go to Line

     Move the cursor to the beginning of the line requested and make
     that line visible.  A request past the end of the file goes to the
     end.  Clear any selection and update the line and column status.

Show Completions

     Open a scrollable list allowing selection of existing names.  See
     *note Completions: 40c1. in the Editing and Navigation section
     below.

Expand Word

     Expand a prefix you have typed to match a full word in the same
     window; repeat to get a different expansion.

Show Call Tip

     After an unclosed parenthesis for a function, open a small window
     with function parameter hints.  See *note Calltips: 40c2. in the
     Editing and Navigation section below.

Show Surrounding Parens

     Highlight the surrounding parenthesis.


File: python.info,  Node: Format menu Editor window only,  Next: Run menu Editor window only,  Prev: Edit menu Shell and Editor,  Up: Menus

5.25.9.4 Format menu (Editor window only)
.........................................

Format Paragraph

     Rewrap the text block containing the text insert cursor.  Avoid
     code lines.  See *note Format block: 40c5. in the Editing and
     Navigation section below.

Indent Region

     Shift selected lines right by the indent width (default 4 spaces).

Dedent Region

     Shift selected lines left by the indent width (default 4 spaces).

Comment Out Region

     Insert ## in front of selected lines.

Uncomment Region

     Remove leading # or ## from selected lines.

Tabify Region

     Turn 'leading' stretches of spaces into tabs.  (Note: We recommend
     using 4 space blocks to indent Python code.)

Untabify Region

     Turn 'all' tabs into the correct number of spaces.

Toggle Tabs

     Open a dialog to switch between indenting with spaces and tabs.

New Indent Width

     Open a dialog to change indent width.  The accepted default by the
     Python community is 4 spaces.

Strip Trailing Whitespace

     Remove trailing space and other whitespace characters after the
     last non-whitespace character of a line by applying *note
     str.rstrip(): 1500. to each line, including lines within multiline
     strings.  Except for Shell windows, remove extra newlines at the
     end of the file.


File: python.info,  Node: Run menu Editor window only,  Next: Shell menu Shell window only,  Prev: Format menu Editor window only,  Up: Menus

5.25.9.5 Run menu (Editor window only)
......................................

Run Module

     Do *note Check Module: 40c8.  If no error, restart the shell to
     clean the environment, then execute the module.  Output is
     displayed in the Shell window.  Note that output requires use of
     ‘print’ or ‘write’.  When execution is complete, the Shell retains
     focus and displays a prompt.  At this point, one may interactively
     explore the result of execution.  This is similar to executing a
     file with ‘python -i file’ at a command line.

Run… Customized

     Same as *note Run Module: 40c7, but run the module with customized
     settings.  'Command Line Arguments' extend *note sys.argv: 12ab. as
     if passed on a command line.  The module can be run in the Shell
     without restarting.

Check Module

     Check the syntax of the module currently open in the Editor window.
     If the module has not been saved IDLE will either prompt the user
     to save or autosave, as selected in the General tab of the Idle
     Settings dialog.  If there is a syntax error, the approximate
     location is indicated in the Editor window.

Python Shell

     Open or wake up the Python Shell window.


File: python.info,  Node: Shell menu Shell window only,  Next: Debug menu Shell window only,  Prev: Run menu Editor window only,  Up: Menus

5.25.9.6 Shell menu (Shell window only)
.......................................

View Last Restart

     Scroll the shell window to the last Shell restart.

Restart Shell

     Restart the shell to clean the environment and reset display and
     exception handling.

Previous History

     Cycle through earlier commands in history which match the current
     entry.

Next History

     Cycle through later commands in history which match the current
     entry.

Interrupt Execution

     Stop a running program.


File: python.info,  Node: Debug menu Shell window only,  Next: Options menu Shell and Editor,  Prev: Shell menu Shell window only,  Up: Menus

5.25.9.7 Debug menu (Shell window only)
.......................................

Go to File/Line

     Look on the current line.  with the cursor, and the line above for
     a filename and line number.  If found, open the file if not already
     open, and show the line.  Use this to view source lines referenced
     in an exception traceback and lines found by Find in Files.  Also
     available in the context menu of the Shell window and Output
     windows.

Debugger (toggle)

     When activated, code entered in the Shell or run from an Editor
     will run under the debugger.  In the Editor, breakpoints can be set
     with the context menu.  This feature is still incomplete and
     somewhat experimental.

Stack Viewer

     Show the stack traceback of the last exception in a tree widget,
     with access to locals and globals.

Auto-open Stack Viewer

     Toggle automatically opening the stack viewer on an unhandled
     exception.


File: python.info,  Node: Options menu Shell and Editor,  Next: Window menu Shell and Editor,  Prev: Debug menu Shell window only,  Up: Menus

5.25.9.8 Options menu (Shell and Editor)
........................................

Configure IDLE

     Open a configuration dialog and change preferences for the
     following: fonts, indentation, keybindings, text color themes,
     startup windows and size, additional help sources, and extensions.
     On macOS, open the configuration dialog by selecting Preferences in
     the application menu.  For more details, see *note Setting
     preferences: 40ce. under Help and preferences.

Most configuration options apply to all windows or all future windows.
The option items below only apply to the active window.

Show/Hide Code Context (Editor Window only)

     Open a pane at the top of the edit window which shows the block
     context of the code which has scrolled above the top of the window.
     See *note Code Context: 40cf. in the Editing and Navigation section
     below.

Show/Hide Line Numbers (Editor Window only)

     Open a column to the left of the edit window which shows the number
     of each line of text.  The default is off, which may be changed in
     the preferences (see *note Setting preferences: 40ce.).

Zoom/Restore Height

     Toggles the window between normal size and maximum height.  The
     initial size defaults to 40 lines by 80 chars unless changed on the
     General tab of the Configure IDLE dialog.  The maximum height for a
     screen is determined by momentarily maximizing a window the first
     time one is zoomed on the screen.  Changing screen settings may
     invalidate the saved height.  This toggle has no effect when a
     window is maximized.


File: python.info,  Node: Window menu Shell and Editor,  Next: Help menu Shell and Editor,  Prev: Options menu Shell and Editor,  Up: Menus

5.25.9.9 Window menu (Shell and Editor)
.......................................

Lists the names of all open windows; select one to bring it to the
foreground (deiconifying it if necessary).


File: python.info,  Node: Help menu Shell and Editor,  Next: Context menus,  Prev: Window menu Shell and Editor,  Up: Menus

5.25.9.10 Help menu (Shell and Editor)
......................................

About IDLE

     Display version, copyright, license, credits, and more.

IDLE Help

     Display this IDLE document, detailing the menu options, basic
     editing and navigation, and other tips.

Python Docs

     Access local Python documentation, if installed, or start a web
     browser and open docs.python.org showing the latest Python
     documentation.

Turtle Demo

     Run the turtledemo module with example Python code and turtle
     drawings.

Additional help sources may be added here with the Configure IDLE dialog
under the General tab.  See the *note Help sources: 40d2. subsection
below for more on Help menu choices.


File: python.info,  Node: Context menus,  Prev: Help menu Shell and Editor,  Up: Menus

5.25.9.11 Context menus
.......................

Open a context menu by right-clicking in a window (Control-click on
macOS). Context menus have the standard clipboard functions also on the
Edit menu.

Cut

     Copy selection into the system-wide clipboard; then delete the
     selection.

Copy

     Copy selection into the system-wide clipboard.

Paste

     Insert contents of the system-wide clipboard into the current
     window.

Editor windows also have breakpoint functions.  Lines with a breakpoint
set are specially marked.  Breakpoints only have an effect when running
under the debugger.  Breakpoints for a file are saved in the user’s
‘.idlerc’ directory.

Set Breakpoint

     Set a breakpoint on the current line.

Clear Breakpoint

     Clear the breakpoint on that line.

Shell and Output windows also have the following.

Go to file/line

     Same as in Debug menu.

The Shell window also has an output squeezing facility explained in the
'Python Shell window' subsection below.

Squeeze

     If the cursor is over an output line, squeeze all the output
     between the code above and the prompt below down to a ‘Squeezed
     text’ label.


File: python.info,  Node: Editing and Navigation,  Next: Startup and Code Execution,  Prev: Menus,  Up: IDLE — Python editor and shell<2>

5.25.9.12 Editing and Navigation
................................

* Menu:

* Editor windows::
* Key bindings::
* Automatic indentation::
* Search and Replace::
* Completions::
* Calltips::
* Format block::
* Code Context::
* Shell window::
* Text colors::


File: python.info,  Node: Editor windows,  Next: Key bindings,  Up: Editing and Navigation

5.25.9.13 Editor windows
........................

IDLE may open editor windows when it starts, depending on settings and
how you start IDLE. Thereafter, use the File menu.  There can be only
one open editor window for a given file.

The title bar contains the name of the file, the full path, and the
version of Python and IDLE running the window.  The status bar contains
the line number (‘Ln’) and column number (‘Col’).  Line numbers start
with 1; column numbers with 0.

IDLE assumes that files with a known .py* extension contain Python code
and that other files do not.  Run Python code with the Run menu.


File: python.info,  Node: Key bindings,  Next: Automatic indentation,  Prev: Editor windows,  Up: Editing and Navigation

5.25.9.14 Key bindings
......................

The IDLE insertion cursor is a thin vertical bar between character
positions.  When characters are entered, the insertion cursor and
everything to its right moves right one character and the new character
is entered in the new space.

Several non-character keys move the cursor and possibly delete
characters.  Deletion does not puts text on the clipboard, but IDLE has
an undo list.  Wherever this doc discusses keys, ‘C’ refers to the
‘Control’ key on Windows and Unix and the ‘Command’ key on macOS. (And
all such discussions assume that the keys have not been re-bound to
something else.)

   * Arrow keys move the cursor one character or line.

   * ‘C’-‘LeftArrow’ and ‘C’-‘RightArrow’ moves left or right one word.

   * ‘Home’ and ‘End’ go to the beginning or end of the line.

   * ‘Page Up’ and ‘Page Down’ go up or down one screen.

   * ‘C’-‘Home’ and ‘C’-‘End’ go to beginning or end of the file.

   * ‘Backspace’ and ‘Del’ (or ‘C’-‘d’) delete the previous or next
     character.

   * ‘C’-‘Backspace’ and ‘C’-‘Del’ delete one word left or right.

   * ‘C’-‘k’ deletes (‘kills’) everything to the right.

Standard keybindings (like ‘C’-‘c’ to copy and ‘C’-‘v’ to paste) may
work.  Keybindings are selected in the Configure IDLE dialog.


File: python.info,  Node: Automatic indentation,  Next: Search and Replace,  Prev: Key bindings,  Up: Editing and Navigation

5.25.9.15 Automatic indentation
...............................

After a block-opening statement, the next line is indented by 4 spaces
(in the Python Shell window by one tab).  After certain keywords (break,
return etc.)  the next line is dedented.  In leading indentation,
‘Backspace’ deletes up to 4 spaces if they are there.  ‘Tab’ inserts
spaces (in the Python Shell window one tab), number depends on Indent
width.  Currently, tabs are restricted to four spaces due to Tcl/Tk
limitations.

See also the indent/dedent region commands on the *note Format menu:
40c3.


File: python.info,  Node: Search and Replace,  Next: Completions,  Prev: Automatic indentation,  Up: Editing and Navigation

5.25.9.16 Search and Replace
............................

Any selection becomes a search target.  However, only selections within
a line work because searches are only performed within lines with the
terminal newline removed.  If ‘[x] Regular expression’ is checked, the
target is interpreted according to the Python re module.


File: python.info,  Node: Completions,  Next: Calltips,  Prev: Search and Replace,  Up: Editing and Navigation

5.25.9.17 Completions
.....................

Completions are supplied, when requested and available, for module
names, attributes of classes or functions, or filenames.  Each request
method displays a completion box with existing names.  (See tab
completions below for an exception.)  For any box, change the name being
completed and the item highlighted in the box by typing and deleting
characters; by hitting ‘Up’, ‘Down’, ‘PageUp’, ‘PageDown’, ‘Home’, and
‘End’ keys; and by a single click within the box.  Close the box with
‘Escape’, ‘Enter’, and double ‘Tab’ keys or clicks outside the box.  A
double click within the box selects and closes.

One way to open a box is to type a key character and wait for a
predefined interval.  This defaults to 2 seconds; customize it in the
settings dialog.  (To prevent auto popups, set the delay to a large
number of milliseconds, such as 100000000.)  For imported module names
or class or function attributes, type ‘.’.  For filenames in the root
directory, type *note os.sep: 66d. or *note os.altsep: 66e. immediately
after an opening quote.  (On Windows, one can specify a drive first.)
Move into subdirectories by typing a directory name and a separator.

Instead of waiting, or after a box is closed, open a completion box
immediately with Show Completions on the Edit menu.  The default hot key
is ‘C’-‘space’.  If one types a prefix for the desired name before
opening the box, the first match or near miss is made visible.  The
result is the same as if one enters a prefix after the box is displayed.
Show Completions after a quote completes filenames in the current
directory instead of a root directory.

Hitting ‘Tab’ after a prefix usually has the same effect as Show
Completions.  (With no prefix, it indents.)  However, if there is only
one match to the prefix, that match is immediately added to the editor
text without opening a box.

Invoking ‘Show Completions’, or hitting ‘Tab’ after a prefix, outside of
a string and without a preceding ‘.’ opens a box with keywords, builtin
names, and available module-level names.

When editing code in an editor (as oppose to Shell), increase the
available module-level names by running your code and not restarting the
Shell thereafter.  This is especially useful after adding imports at the
top of a file.  This also increases possible attribute completions.

Completion boxes initially exclude names beginning with ‘_’ or, for
modules, not included in ‘__all__’.  The hidden names can be accessed by
typing ‘_’ after ‘.’, either before or after the box is opened.


File: python.info,  Node: Calltips,  Next: Format block,  Prev: Completions,  Up: Editing and Navigation

5.25.9.18 Calltips
..................

A calltip is shown automatically when one types ‘(’ after the name of an
'accessible' function.  A function name expression may include dots and
subscripts.  A calltip remains until it is clicked, the cursor is moved
out of the argument area, or ‘)’ is typed.  Whenever the cursor is in
the argument part of a definition, select Edit and “Show Call Tip” on
the menu or enter its shortcut to display a calltip.

The calltip consists of the function’s signature and docstring up to the
latter’s first blank line or the fifth non-blank line.  (Some builtin
functions lack an accessible signature.)  A ‘/’ or ‘*’ in the signature
indicates that the preceding or following arguments are passed by
position or name (keyword) only.  Details are subject to change.

In Shell, the accessible functions depends on what modules have been
imported into the user process, including those imported by Idle itself,
and which definitions have been run, all since the last restart.

For example, restart the Shell and enter ‘itertools.count(’.  A calltip
appears because Idle imports itertools into the user process for its own
use.  (This could change.)  Enter ‘turtle.write(’ and nothing appears.
Idle does not itself import turtle.  The menu entry and shortcut also do
nothing.  Enter ‘import turtle’.  Thereafter, ‘turtle.write(’ will
display a calltip.

In an editor, import statements have no effect until one runs the file.
One might want to run a file after writing import statements, after
adding function definitions, or after opening an existing file.


File: python.info,  Node: Format block,  Next: Code Context,  Prev: Calltips,  Up: Editing and Navigation

5.25.9.19 Format block
......................

Reformat Paragraph rewraps a block (‘paragraph’) of contiguous equally
indented non-blank comments, a similar block of text within a multiline
string, or a selected subset of either.  If needed, add a blank line to
separate string from code.  Partial lines in a selection expand to
complete lines.  The resulting lines have the same indent as before but
have maximum total length of N columns (characters).  Change the default
N of 72 on the Window tab of IDLE Settings.


File: python.info,  Node: Code Context,  Next: Shell window,  Prev: Format block,  Up: Editing and Navigation

5.25.9.20 Code Context
......................

Within an editor window containing Python code, code context can be
toggled in order to show or hide a pane at the top of the window.  When
shown, this pane freezes the opening lines for block code, such as those
beginning with ‘class’, ‘def’, or ‘if’ keywords, that would have
otherwise scrolled out of view.  The size of the pane will be expanded
and contracted as needed to show the all current levels of context, up
to the maximum number of lines defined in the Configure IDLE dialog
(which defaults to 15).  If there are no current context lines and the
feature is toggled on, a single blank line will display.  Clicking on a
line in the context pane will move that line to the top of the editor.

The text and background colors for the context pane can be configured
under the Highlights tab in the Configure IDLE dialog.


File: python.info,  Node: Shell window,  Next: Text colors,  Prev: Code Context,  Up: Editing and Navigation

5.25.9.21 Shell window
......................

In IDLE’s Shell, enter, edit, and recall complete statements.  (Most
consoles and terminals only work with a single physical line at a time).

Submit a single-line statement for execution by hitting ‘Return’ with
the cursor anywhere on the line.  If a line is extended with Backslash
(‘\’), the cursor must be on the last physical line.  Submit a
multi-line compound statement by entering a blank line after the
statement.

When one pastes code into Shell, it is not compiled and possibly
executed until one hits ‘Return’, as specified above.  One may edit
pasted code first.  If one pastes more than one statement into Shell,
the result will be a *note SyntaxError: 18d. when multiple statements
are compiled as if they were one.

Lines containing ‘RESTART’ mean that the user execution process has been
re-started.  This occurs when the user execution process has crashed,
when one requests a restart on the Shell menu, or when one runs code in
an editor window.

The editing features described in previous subsections work when
entering code interactively.  IDLE’s Shell window also responds to the
following:

   * ‘C’-‘c’ attempts to interrupt statement execution (but may fail).

   * ‘C’-‘d’ closes Shell if typed at a ‘>>>’ prompt.

   * ‘Alt’-‘p’ and ‘Alt’-‘n’ (‘C’-‘p’ and ‘C’-‘n’ on macOS) retrieve to
     the current prompt the previous or next previously entered
     statement that matches anything already typed.

   * ‘Return’ while the cursor is on any previous statement appends the
     latter to anything already typed at the prompt.


File: python.info,  Node: Text colors,  Prev: Shell window,  Up: Editing and Navigation

5.25.9.22 Text colors
.....................

Idle defaults to black on white text, but colors text with special
meanings.  For the shell, these are shell output, shell error, user
output, and user error.  For Python code, at the shell prompt or in an
editor, these are keywords, builtin class and function names, names
following ‘class’ and ‘def’, strings, and comments.  For any text
window, these are the cursor (when present), found text (when possible),
and selected text.

IDLE also highlights the *note soft keywords: 812. *note match: 813,
‘case’, and *note _: 814. in pattern-matching statements.  However, this
highlighting is not perfect and will be incorrect in some rare cases,
including some ‘_’-s in ‘case’ patterns.

Text coloring is done in the background, so uncolorized text is
occasionally visible.  To change the color scheme, use the Configure
IDLE dialog Highlighting tab.  The marking of debugger breakpoint lines
in the editor and text in popups and dialogs is not user-configurable.


File: python.info,  Node: Startup and Code Execution,  Next: Help and Preferences,  Prev: Editing and Navigation,  Up: IDLE — Python editor and shell<2>

5.25.9.23 Startup and Code Execution
....................................

Upon startup with the ‘-s’ option, IDLE will execute the file referenced
by the environment variables ‘IDLESTARTUP’ or *note PYTHONSTARTUP: 1003.
IDLE first checks for ‘IDLESTARTUP’; if ‘IDLESTARTUP’ is present the
file referenced is run.  If ‘IDLESTARTUP’ is not present, IDLE checks
for ‘PYTHONSTARTUP’.  Files referenced by these environment variables
are convenient places to store functions that are used frequently from
the IDLE shell, or for executing import statements to import common
modules.

In addition, ‘Tk’ also loads a startup file if it is present.  Note that
the Tk file is loaded unconditionally.  This additional file is
‘.Idle.py’ and is looked for in the user’s home directory.  Statements
in this file will be executed in the Tk namespace, so this file is not
useful for importing functions to be used from IDLE’s Python shell.

* Menu:

* Command-line usage: Command-line usage<3>.
* Startup failure::
* Running user code::
* User output in Shell::
* Developing tkinter applications::
* Running without a subprocess::


File: python.info,  Node: Command-line usage<3>,  Next: Startup failure,  Up: Startup and Code Execution

5.25.9.24 Command-line usage
............................

IDLE can be invoked from the command line with various options.  The
general syntax is:

     python -m idlelib [options] [file ...]

The following options are available:

 -- Option: -c <command>

     Run the specified Python command in the shell window.  For example,
     pass ‘-c "print('Hello, World!')"’.  On Windows, the outer quotes
     must be double quotes as shown.

 -- Option: -d

     Enable the debugger and open the shell window.

 -- Option: -e

     Open an editor window.

 -- Option: -h

     Print a help message with legal combinations of options and exit.

 -- Option: -i

     Open a shell window.

 -- Option: -r <file>

     Run the specified file in the shell window.

 -- Option: -s

     Run the startup file (as defined by the environment variables
     ‘IDLESTARTUP’ or *note PYTHONSTARTUP: 1003.) before opening the
     shell window.

 -- Option: -t <title>

     Set the title of the shell window.

 -- Option: -

     Read and execute standard input in the shell window.  This option
     must be the last one before any arguments.

If arguments are provided:

   - If ‘-’, ‘-c’, or ‘-r’ is used, all arguments are placed in
     ‘sys.argv[1:]’, and ‘sys.argv[0]’ is set to ‘''’, ‘'-c'’, or ‘'-r'’
     respectively.  No editor window is opened, even if that is the
     default set in the 'Options' dialog.

   - Otherwise, arguments are treated as files to be opened for editing,
     and ‘sys.argv’ reflects the arguments passed to IDLE itself.


File: python.info,  Node: Startup failure,  Next: Running user code,  Prev: Command-line usage<3>,  Up: Startup and Code Execution

5.25.9.25 Startup failure
.........................

IDLE uses a socket to communicate between the IDLE GUI process and the
user code execution process.  A connection must be established whenever
the Shell starts or restarts.  (The latter is indicated by a divider
line that says ‘RESTART’).  If the user process fails to connect to the
GUI process, it usually displays a ‘Tk’ error box with a ‘cannot
connect’ message that directs the user here.  It then exits.

One specific connection failure on Unix systems results from
misconfigured masquerading rules somewhere in a system’s network setup.
When IDLE is started from a terminal, one will see a message starting
with ‘** Invalid host:’.  The valid value is ‘127.0.0.1
(idlelib.rpc.LOCALHOST)’.  One can diagnose with ‘tcpconnect -irv
127.0.0.1 6543’ in one terminal window and ‘tcplisten <same args>’ in
another.

A common cause of failure is a user-written file with the same name as a
standard library module, such as 'random.py' and 'tkinter.py'.  When
such a file is located in the same directory as a file that is about to
be run, IDLE cannot import the stdlib file.  The current fix is to
rename the user file.

Though less common than in the past, an antivirus or firewall program
may stop the connection.  If the program cannot be taught to allow the
connection, then it must be turned off for IDLE to work.  It is safe to
allow this internal connection because no data is visible on external
ports.  A similar problem is a network mis-configuration that blocks
connections.

Python installation issues occasionally stop IDLE: multiple versions can
clash, or a single installation might need admin access.  If one undo
the clash, or cannot or does not want to run as admin, it might be
easiest to completely remove Python and start over.

A zombie pythonw.exe process could be a problem.  On Windows, use Task
Manager to check for one and stop it if there is.  Sometimes a restart
initiated by a program crash or Keyboard Interrupt (control-C) may fail
to connect.  Dismissing the error box or using Restart Shell on the
Shell menu may fix a temporary problem.

When IDLE first starts, it attempts to read user configuration files in
‘~/.idlerc/’ (~ is one’s home directory).  If there is a problem, an
error message should be displayed.  Leaving aside random disk glitches,
this can be prevented by never editing the files by hand.  Instead, use
the configuration dialog, under Options.  Once there is an error in a
user configuration file, the best solution may be to delete it and start
over with the settings dialog.

If IDLE quits with no message, and it was not started from a console,
try starting it from a console or terminal (‘python -m idlelib’) and see
if this results in an error message.

On Unix-based systems with tcl/tk older than ‘8.6.11’ (see ‘About IDLE’)
certain characters of certain fonts can cause a tk failure with a
message to the terminal.  This can happen either if one starts IDLE to
edit a file with such a character or later when entering such a
character.  If one cannot upgrade tcl/tk, then re-configure IDLE to use
a font that works better.


File: python.info,  Node: Running user code,  Next: User output in Shell,  Prev: Startup failure,  Up: Startup and Code Execution

5.25.9.26 Running user code
...........................

With rare exceptions, the result of executing Python code with IDLE is
intended to be the same as executing the same code by the default
method, directly with Python in a text-mode system console or terminal
window.  However, the different interface and operation occasionally
affect visible results.  For instance, ‘sys.modules’ starts with more
entries, and ‘threading.active_count()’ returns 2 instead of 1.

By default, IDLE runs user code in a separate OS process rather than in
the user interface process that runs the shell and editor.  In the
execution process, it replaces ‘sys.stdin’, ‘sys.stdout’, and
‘sys.stderr’ with objects that get input from and send output to the
Shell window.  The original values stored in ‘sys.__stdin__’,
‘sys.__stdout__’, and ‘sys.__stderr__’ are not touched, but may be
‘None’.

Sending print output from one process to a text widget in another is
slower than printing to a system terminal in the same process.  This has
the most effect when printing multiple arguments, as the string for each
argument, each separator, the newline are sent separately.  For
development, this is usually not a problem, but if one wants to print
faster in IDLE, format and join together everything one wants displayed
together and then print a single string.  Both format strings and *note
str.join(): 2363. can help combine fields and lines.

IDLE’s standard stream replacements are not inherited by subprocesses
created in the execution process, whether directly by user code or by
modules such as multiprocessing.  If such subprocess use ‘input’ from
sys.stdin or ‘print’ or ‘write’ to sys.stdout or sys.stderr, IDLE should
be started in a command line window.  (On Windows, use ‘python’ or ‘py’
rather than ‘pythonw’ or ‘pyw’.)  The secondary subprocess will then be
attached to that window for input and output.

If ‘sys’ is reset by user code, such as with ‘importlib.reload(sys)’,
IDLE’s changes are lost and input from the keyboard and output to the
screen will not work correctly.

When Shell has the focus, it controls the keyboard and screen.  This is
normally transparent, but functions that directly access the keyboard
and screen will not work.  These include system-specific functions that
determine whether a key has been pressed and if so, which.

The IDLE code running in the execution process adds frames to the call
stack that would not be there otherwise.  IDLE wraps
‘sys.getrecursionlimit’ and ‘sys.setrecursionlimit’ to reduce the effect
of the additional stack frames.

When user code raises SystemExit either directly or by calling sys.exit,
IDLE returns to a Shell prompt instead of exiting.


File: python.info,  Node: User output in Shell,  Next: Developing tkinter applications,  Prev: Running user code,  Up: Startup and Code Execution

5.25.9.27 User output in Shell
..............................

When a program outputs text, the result is determined by the
corresponding output device.  When IDLE executes user code, ‘sys.stdout’
and ‘sys.stderr’ are connected to the display area of IDLE’s Shell.
Some of its features are inherited from the underlying Tk Text widget.
Others are programmed additions.  Where it matters, Shell is designed
for development rather than production runs.

For instance, Shell never throws away output.  A program that sends
unlimited output to Shell will eventually fill memory, resulting in a
memory error.  In contrast, some system text windows only keep the last
n lines of output.  A Windows console, for instance, keeps a
user-settable 1 to 9999 lines, with 300 the default.

A Tk Text widget, and hence IDLE’s Shell, displays characters
(codepoints) in the BMP (Basic Multilingual Plane) subset of Unicode.
Which characters are displayed with a proper glyph and which with a
replacement box depends on the operating system and installed fonts.
Tab characters cause the following text to begin after the next tab
stop.  (They occur every 8 ‘characters’).  Newline characters cause
following text to appear on a new line.  Other control characters are
ignored or displayed as a space, box, or something else, depending on
the operating system and font.  (Moving the text cursor through such
output with arrow keys may exhibit some surprising spacing behavior.)

     >>> s = 'a\tb\a<\x02><\r>\bc\nd'  # Enter 22 chars.
     >>> len(s)
     14
     >>> s  # Display repr(s)
     'a\tb\x07<\x02><\r>\x08c\nd'
     >>> print(s, end='')  # Display s as is.
     # Result varies by OS and font.  Try it.

The ‘repr’ function is used for interactive echo of expression values.
It returns an altered version of the input string in which control
codes, some BMP codepoints, and all non-BMP codepoints are replaced with
escape codes.  As demonstrated above, it allows one to identify the
characters in a string, regardless of how they are displayed.

Normal and error output are generally kept separate (on separate lines)
from code input and each other.  They each get different highlight
colors.

For SyntaxError tracebacks, the normal ‘^’ marking where the error was
detected is replaced by coloring the text with an error highlight.  When
code run from a file causes other exceptions, one may right click on a
traceback line to jump to the corresponding line in an IDLE editor.  The
file will be opened if necessary.

Shell has a special facility for squeezing output lines down to a
‘Squeezed text’ label.  This is done automatically for output over N
lines (N = 50 by default).  N can be changed in the PyShell section of
the General page of the Settings dialog.  Output with fewer lines can be
squeezed by right clicking on the output.  This can be useful lines long
enough to slow down scrolling.

Squeezed output is expanded in place by double-clicking the label.  It
can also be sent to the clipboard or a separate view window by
right-clicking the label.


File: python.info,  Node: Developing tkinter applications,  Next: Running without a subprocess,  Prev: User output in Shell,  Up: Startup and Code Execution

5.25.9.28 Developing tkinter applications
.........................................

IDLE is intentionally different from standard Python in order to
facilitate development of tkinter programs.  Enter ‘import tkinter as
tk; root = tk.Tk()’ in standard Python and nothing appears.  Enter the
same in IDLE and a tk window appears.  In standard Python, one must also
enter ‘root.update()’ to see the window.  IDLE does the equivalent in
the background, about 20 times a second, which is about every 50
milliseconds.  Next enter ‘b = tk.Button(root, text='button');
b.pack()’.  Again, nothing visibly changes in standard Python until one
enters ‘root.update()’.

Most tkinter programs run ‘root.mainloop()’, which usually does not
return until the tk app is destroyed.  If the program is run with
‘python -i’ or from an IDLE editor, a ‘>>>’ shell prompt does not appear
until ‘mainloop()’ returns, at which time there is nothing left to
interact with.

When running a tkinter program from an IDLE editor, one can comment out
the mainloop call.  One then gets a shell prompt immediately and can
interact with the live application.  One just has to remember to
re-enable the mainloop call when running in standard Python.


File: python.info,  Node: Running without a subprocess,  Prev: Developing tkinter applications,  Up: Startup and Code Execution

5.25.9.29 Running without a subprocess
......................................

By default, IDLE executes user code in a separate subprocess via a
socket, which uses the internal loopback interface.  This connection is
not externally visible and no data is sent to or received from the
internet.  If firewall software complains anyway, you can ignore it.

If the attempt to make the socket connection fails, Idle will notify
you.  Such failures are sometimes transient, but if persistent, the
problem may be either a firewall blocking the connection or
misconfiguration of a particular system.  Until the problem is fixed,
one can run Idle with the -n command line switch.

If IDLE is started with the -n command line switch it will run in a
single process and will not create the subprocess which runs the RPC
Python execution server.  This can be useful if Python cannot create the
subprocess or the RPC socket interface on your platform.  However, in
this mode user code is not isolated from IDLE itself.  Also, the
environment is not restarted when Run/Run Module (F5) is selected.  If
your code has been modified, you must reload() the affected modules and
re-import any specific items (e.g.  from foo import baz) if the changes
are to take effect.  For these reasons, it is preferable to run IDLE
with the default subprocess if at all possible.

Deprecated since version 3.4.


File: python.info,  Node: Help and Preferences,  Next: idlelib — implementation of IDLE application,  Prev: Startup and Code Execution,  Up: IDLE — Python editor and shell<2>

5.25.9.30 Help and Preferences
..............................

* Menu:

* Help sources::
* Setting preferences::
* IDLE on macOS::
* Extensions::


File: python.info,  Node: Help sources,  Next: Setting preferences,  Up: Help and Preferences

5.25.9.31 Help sources
......................

Help menu entry “IDLE Help” displays a formatted html version of the
IDLE chapter of the Library Reference.  The result, in a read-only
tkinter text window, is close to what one sees in a web browser.
Navigate through the text with a mousewheel, the scrollbar, or up and
down arrow keys held down.  Or click the TOC (Table of Contents) button
and select a section header in the opened box.

Help menu entry “Python Docs” opens the extensive sources of help,
including tutorials, available at ‘docs.python.org/x.y’, where ‘x.y’ is
the currently running Python version.  If your system has an off-line
copy of the docs (this may be an installation option), that will be
opened instead.

Selected URLs can be added or removed from the help menu at any time
using the General tab of the Configure IDLE dialog.


File: python.info,  Node: Setting preferences,  Next: IDLE on macOS,  Prev: Help sources,  Up: Help and Preferences

5.25.9.32 Setting preferences
.............................

The font preferences, highlighting, keys, and general preferences can be
changed via Configure IDLE on the Option menu.  Non-default user
settings are saved in a ‘.idlerc’ directory in the user’s home
directory.  Problems caused by bad user configuration files are solved
by editing or deleting one or more of the files in ‘.idlerc’.

On the Font tab, see the text sample for the effect of font face and
size on multiple characters in multiple languages.  Edit the sample to
add other characters of personal interest.  Use the sample to select
monospaced fonts.  If particular characters have problems in Shell or an
editor, add them to the top of the sample and try changing first size
and then font.

On the Highlights and Keys tab, select a built-in or custom color theme
and key set.  To use a newer built-in color theme or key set with older
IDLEs, save it as a new custom theme or key set and it well be
accessible to older IDLEs.


File: python.info,  Node: IDLE on macOS,  Next: Extensions,  Prev: Setting preferences,  Up: Help and Preferences

5.25.9.33 IDLE on macOS
.......................

Under System Preferences: Dock, one can set “Prefer tabs when opening
documents” to “Always”.  This setting is not compatible with the
tk/tkinter GUI framework used by IDLE, and it breaks a few IDLE
features.


File: python.info,  Node: Extensions,  Prev: IDLE on macOS,  Up: Help and Preferences

5.25.9.34 Extensions
....................

IDLE contains an extension facility.  Preferences for extensions can be
changed with the Extensions tab of the preferences dialog.  See the
beginning of config-extensions.def in the idlelib directory for further
information.  The only current default extension is zzdummy, an example
also used for testing.


File: python.info,  Node: idlelib — implementation of IDLE application,  Prev: Help and Preferences,  Up: IDLE — Python editor and shell<2>

5.25.9.35 idlelib — implementation of IDLE application
......................................................

'Source code:' Lib/idlelib(1)

__________________________________________________________________

The Lib/idlelib package implements the IDLE application.  See the rest
of this page for how to use IDLE.

The files in idlelib are described in idlelib/README.txt.  Access it
either in idlelib or click Help => About IDLE on the IDLE menu.  This
file also maps IDLE menu items to the code that implements the item.
Except for files listed under ‘Startup’, the idlelib code is ‘private’
in sense that feature changes can be backported (see PEP 434(2)).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/idlelib

   (2) https://peps.python.org/pep-0434/


File: python.info,  Node: turtle — Turtle graphics,  Prev: IDLE — Python editor and shell<2>,  Up: Graphical user interfaces with Tk

5.25.10 ‘turtle’ — Turtle graphics
----------------------------------

'Source code:' Lib/turtle.py(1)

__________________________________________________________________

* Menu:

* Introduction: Introduction<11>.
* Get started::
* Tutorial: Tutorial<4>.
* How to…::
* Turtle graphics reference::
* Methods of RawTurtle/Turtle and corresponding functions::
* Methods of TurtleScreen/Screen and corresponding functions::
* Public classes::
* Explanation: Explanation<2>.
* Help and configuration::
* turtledemo — Demo scripts::
* Changes since Python 2.6: Changes since Python 2 6.
* Changes since Python 3.0: Changes since Python 3 0.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/turtle.py


File: python.info,  Node: Introduction<11>,  Next: Get started,  Up: turtle — Turtle graphics

5.25.10.1 Introduction
......................

Turtle graphics is an implementation of the popular geometric drawing
tools introduced in Logo(1), developed by Wally Feurzeig, Seymour Papert
and Cynthia Solomon in 1967.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Turtle_(robot)


File: python.info,  Node: Get started,  Next: Tutorial<4>,  Prev: Introduction<11>,  Up: turtle — Turtle graphics

5.25.10.2 Get started
.....................

Imagine a robotic turtle starting at (0, 0) in the x-y plane.  After an
‘import turtle’, give it the command ‘turtle.forward(15)’, and it moves
(on-screen!)  15 pixels in the direction it is facing, drawing a line as
it moves.  Give it the command ‘turtle.right(25)’, and it rotates
in-place 25 degrees clockwise.

Turtle star
...........

Turtle can draw intricate shapes using programs that repeat simple
moves.

[image src="python-figures/turtle-star.png"]


In Python, turtle graphics provides a representation of a physical
“turtle” (a little robot with a pen) that draws on a sheet of paper on
the floor.

It’s an effective and well-proven way for learners to encounter
programming concepts and interaction with software, as it provides
instant, visible feedback.  It also provides convenient access to
graphical output in general.

Turtle drawing was originally created as an educational tool, to be used
by teachers in the classroom.  For the programmer who needs to produce
some graphical output it can be a way to do that without the overhead of
introducing more complex or external libraries into their work.


File: python.info,  Node: Tutorial<4>,  Next: How to…,  Prev: Get started,  Up: turtle — Turtle graphics

5.25.10.3 Tutorial
..................

New users should start here.  In this tutorial we’ll explore some of the
basics of turtle drawing.

* Menu:

* Starting a turtle environment::
* Basic drawing::
* Making algorithmic patterns::


File: python.info,  Node: Starting a turtle environment,  Next: Basic drawing,  Up: Tutorial<4>

5.25.10.4 Starting a turtle environment
.......................................

In a Python shell, import all the objects of the ‘turtle’ module:

     from turtle import *

If you run into a ‘No module named '_tkinter'’ error, you’ll have to
install the *note Tk interface package: f0. on your system.


File: python.info,  Node: Basic drawing,  Next: Making algorithmic patterns,  Prev: Starting a turtle environment,  Up: Tutorial<4>

5.25.10.5 Basic drawing
.......................

Send the turtle forward 100 steps:

     forward(100)

You should see (most likely, in a new window on your display) a line
drawn by the turtle, heading East.  Change the direction of the turtle,
so that it turns 120 degrees left (anti-clockwise):

     left(120)

Let’s continue by drawing a triangle:

     forward(100)
     left(120)
     forward(100)

Notice how the turtle, represented by an arrow, points in different
directions as you steer it.

Experiment with those commands, and also with ‘backward()’ and
‘right()’.

* Menu:

* Pen control::
* The turtle’s position::


File: python.info,  Node: Pen control,  Next: The turtle’s position,  Up: Basic drawing

5.25.10.6 Pen control
.....................

Try changing the color - for example, ‘color('blue')’ - and width of the
line - for example, ‘width(3)’ - and then drawing again.

You can also move the turtle around without drawing, by lifting up the
pen: ‘up()’ before moving.  To start drawing again, use ‘down()’.


File: python.info,  Node: The turtle’s position,  Prev: Pen control,  Up: Basic drawing

5.25.10.7 The turtle’s position
...............................

Send your turtle back to its starting-point (useful if it has
disappeared off-screen):

     home()

The home position is at the center of the turtle’s screen.  If you ever
need to know them, get the turtle’s x-y coordinates with:

     pos()

Home is at ‘(0, 0)’.

And after a while, it will probably help to clear the window so we can
start anew:

     clearscreen()


File: python.info,  Node: Making algorithmic patterns,  Prev: Basic drawing,  Up: Tutorial<4>

5.25.10.8 Making algorithmic patterns
.....................................

Using loops, it’s possible to build up geometric patterns:

     for steps in range(100):
         for c in ('blue', 'red', 'green'):
             color(c)
             forward(steps)
             right(30)

- which of course, are limited only by the imagination!

Let’s draw the star shape at the top of this page.  We want red lines,
filled in with yellow:

     color('red')
     fillcolor('yellow')

Just as ‘up()’ and ‘down()’ determine whether lines will be drawn,
filling can be turned on and off:

     begin_fill()

Next we’ll create a loop:

     while True:
         forward(200)
         left(170)
         if abs(pos()) < 1:
             break

‘abs(pos()) < 1’ is a good way to know when the turtle is back at its
home position.

Finally, complete the filling:

     end_fill()

(Note that filling only actually takes place when you give the
‘end_fill()’ command.)


File: python.info,  Node: How to…,  Next: Turtle graphics reference,  Prev: Tutorial<4>,  Up: turtle — Turtle graphics

5.25.10.9 How to…
.................

This section covers some typical turtle use-cases and approaches.

* Menu:

* Get started as quickly as possible::
* Use the turtle module namespace::
* Use turtle graphics in a script::
* Use object-oriented turtle graphics::


File: python.info,  Node: Get started as quickly as possible,  Next: Use the turtle module namespace,  Up: How to…

5.25.10.10 Get started as quickly as possible
.............................................

One of the joys of turtle graphics is the immediate, visual feedback
that’s available from simple commands - it’s an excellent way to
introduce children to programming ideas, with a minimum of overhead (not
just children, of course).

The turtle module makes this possible by exposing all its basic
functionality as functions, available with ‘from turtle import *’.  The
*note turtle graphics tutorial: 40fc. covers this approach.

It’s worth noting that many of the turtle commands also have even more
terse equivalents, such as ‘fd()’ for *note forward(): 3309.  These are
especially useful when working with learners for whom typing is not a
skill.

     You’ll need to have the *note Tk interface package: f0. installed
     on your system for turtle graphics to work.  Be warned that this is
     not always straightforward, so check this in advance if you’re
     planning to use turtle graphics with a learner.


File: python.info,  Node: Use the turtle module namespace,  Next: Use turtle graphics in a script,  Prev: Get started as quickly as possible,  Up: How to…

5.25.10.11 Use the ‘turtle’ module namespace
............................................

Using ‘from turtle import *’ is convenient - but be warned that it
imports a rather large collection of objects, and if you’re doing
anything but turtle graphics you run the risk of a name conflict (this
becomes even more an issue if you’re using turtle graphics in a script
where other modules might be imported).

The solution is to use ‘import turtle’ - ‘fd()’ becomes ‘turtle.fd()’,
‘width()’ becomes ‘turtle.width()’ and so on.  (If typing “turtle” over
and over again becomes tedious, use for example ‘import turtle as t’
instead.)


File: python.info,  Node: Use turtle graphics in a script,  Next: Use object-oriented turtle graphics,  Prev: Use the turtle module namespace,  Up: How to…

5.25.10.12 Use turtle graphics in a script
..........................................

It’s recommended to use the ‘turtle’ module namespace as described
immediately above, for example:

     import turtle as t
     from random import random

     for i in range(100):
         steps = int(random() * 100)
         angle = int(random() * 360)
         t.right(angle)
         t.fd(steps)

Another step is also required though - as soon as the script ends,
Python will also close the turtle’s window.  Add:

     t.mainloop()

to the end of the script.  The script will now wait to be dismissed and
will not exit until it is terminated, for example by closing the turtle
graphics window.


File: python.info,  Node: Use object-oriented turtle graphics,  Prev: Use turtle graphics in a script,  Up: How to…

5.25.10.13 Use object-oriented turtle graphics
..............................................

See also
........

*note Explanation of the object-oriented interface: 410a.

Other than for very basic introductory purposes, or for trying things
out as quickly as possible, it’s more usual and much more powerful to
use the object-oriented approach to turtle graphics.  For example, this
allows multiple turtles on screen at once.

In this approach, the various turtle commands are methods of objects
(mostly of ‘Turtle’ objects).  You 'can' use the object-oriented
approach in the shell, but it would be more typical in a Python script.

The example above then becomes:

     from turtle import Turtle
     from random import random

     t = Turtle()
     for i in range(100):
         steps = int(random() * 100)
         angle = int(random() * 360)
         t.right(angle)
         t.fd(steps)

     t.screen.mainloop()

Note the last line.  ‘t.screen’ is an instance of the *note Screen:
410b. that a Turtle instance exists on; it’s created automatically along
with the turtle.

The turtle’s screen can be customised, for example:

     t.screen.title('Object-oriented turtle demo')
     t.screen.bgcolor("orange")


File: python.info,  Node: Turtle graphics reference,  Next: Methods of RawTurtle/Turtle and corresponding functions,  Prev: How to…,  Up: turtle — Turtle graphics

5.25.10.14 Turtle graphics reference
....................................

     Note: In the following documentation the argument list for
     functions is given.  Methods, of course, have the additional first
     argument 'self' which is omitted here.

* Menu:

* Turtle methods::
* Methods of TurtleScreen/Screen::


File: python.info,  Node: Turtle methods,  Next: Methods of TurtleScreen/Screen,  Up: Turtle graphics reference

5.25.10.15 Turtle methods
.........................

Turtle motion

     Move and draw

               *note forward(): 3309. | *note fd(): 410e.
               *note backward(): 410f. | *note bk(): 4110. | *note back(): 4111.
               *note right(): 4112. | *note rt(): 4113.
               *note left(): 4114. | *note lt(): 4115.
               *note goto(): 4116. | *note setpos(): 4117. | *note setposition(): 4118.
               *note teleport(): 1838.
               *note setx(): 4119.
               *note sety(): 411a.
               *note setheading(): 411b. | *note seth(): 411c.
               *note home(): 411d.
               *note circle(): 411e.
               *note dot(): 411f.
               *note stamp(): 4120.
               *note clearstamp(): 4121.
               *note clearstamps(): 4122.
               *note undo(): 4123.
               *note speed(): 4124.

     Tell Turtle’s state

               *note position(): 4125. | *note pos(): 4126.
               *note towards(): 4127.
               *note xcor(): 4128.
               *note ycor(): 4129.
               *note heading(): 412a.
               *note distance(): 412b.

     Setting and measurement

               *note degrees(): 412c.
               *note radians(): 412d.

Pen control

     Drawing state

               *note pendown(): 412e. | *note pd(): 412f. | *note down(): 4130.
               *note penup(): 4131. | *note pu(): 4132. | *note up(): 4133.
               *note pensize(): 4134. | *note width(): 4135.
               *note pen(): 4136.
               *note isdown(): 4137.

     Color control

               *note color(): 4138.
               *note pencolor(): 4139.
               *note fillcolor(): 413a.

     Filling

               *note filling(): 413b.
               *note begin_fill(): 413c.
               *note end_fill(): 413d.

     More drawing control

               *note reset(): 413e.
               *note clear(): 413f.
               *note write(): 4140.

Turtle state

     Visibility

               *note showturtle(): 4141. | *note st(): 4142.
               *note hideturtle(): 4143. | *note ht(): 4144.
               *note isvisible(): 4145.

     Appearance

               *note shape(): 4146.
               *note resizemode(): 4147.
               *note shapesize(): 4148. | *note turtlesize(): 4149.
               *note shearfactor(): 414a.
               *note tiltangle(): 728.
               *note tilt(): 414b.
               *note shapetransform(): 414c.
               *note get_shapepoly(): 414d.

Using events

          *note onclick(): 414e.
          *note onrelease(): 414f.
          *note ondrag(): 4150.

Special Turtle methods

          *note begin_poly(): 4151.
          *note end_poly(): 4152.
          *note get_poly(): 4153.
          *note clone(): 4154.
          *note getturtle(): 4155. | *note getpen(): 4156.
          *note getscreen(): 4157.
          *note setundobuffer(): 4158.
          *note undobufferentries(): 4159.


File: python.info,  Node: Methods of TurtleScreen/Screen,  Prev: Turtle methods,  Up: Turtle graphics reference

5.25.10.16 Methods of TurtleScreen/Screen
.........................................

Window control

          *note bgcolor(): 415b.
          *note bgpic(): 415c.
          *note clearscreen(): 415d.
          *note resetscreen(): 415e.
          *note screensize(): 415f.
          *note setworldcoordinates(): 4160.

Animation control

          *note delay(): 4161.
          *note tracer(): 4162.
          *note update(): 4163.

Using screen events

          *note listen(): 4164.
          *note onkey(): 4165. | *note onkeyrelease(): 4166.
          *note onkeypress(): 4167.
          *note onclick(): 414e. | *note onscreenclick(): 4168.
          *note ontimer(): 4169.
          *note mainloop(): 416a. | *note done(): 416b.

Settings and special methods

          *note mode(): 416c.
          *note colormode(): 416d.
          *note getcanvas(): 416e.
          *note getshapes(): 416f.
          *note register_shape(): 4170. | *note addshape(): 4171.
          *note turtles(): 4172.
          *note window_height(): 4173.
          *note window_width(): 4174.

Input methods

          *note textinput(): 1a21.
          *note numinput(): 1a22.

Methods specific to Screen

          *note bye(): 4175.
          *note exitonclick(): 4176.
          *note setup(): 4177.
          *note title(): 4178.


File: python.info,  Node: Methods of RawTurtle/Turtle and corresponding functions,  Next: Methods of TurtleScreen/Screen and corresponding functions,  Prev: Turtle graphics reference,  Up: turtle — Turtle graphics

5.25.10.17 Methods of RawTurtle/Turtle and corresponding functions
..................................................................

Most of the examples in this section refer to a Turtle instance called
‘turtle’.

* Menu:

* Turtle motion::
* Tell Turtle’s state::
* Settings for measurement::
* Pen control: Pen control<2>.
* Turtle state::
* Using events::
* Special Turtle methods::
* Compound shapes::


File: python.info,  Node: Turtle motion,  Next: Tell Turtle’s state,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.18 Turtle motion
........................

 -- Function: turtle.forward (distance)
 -- Function: turtle.fd (distance)


     Parameters: ‘distance’ – a number (integer or float)

     Move the turtle forward by the specified 'distance', in the
     direction the turtle is headed.

          >>> turtle.position()
          (0.00,0.00)
          >>> turtle.forward(25)
          >>> turtle.position()
          (25.00,0.00)
          >>> turtle.forward(-75)
          >>> turtle.position()
          (-50.00,0.00)

 -- Function: turtle.back (distance)
 -- Function: turtle.bk (distance)
 -- Function: turtle.backward (distance)


     Parameters: ‘distance’ – a number

     Move the turtle backward by 'distance', opposite to the direction
     the turtle is headed.  Do not change the turtle’s heading.

          >>> turtle.position()
          (0.00,0.00)
          >>> turtle.backward(30)
          >>> turtle.position()
          (-30.00,0.00)

 -- Function: turtle.right (angle)
 -- Function: turtle.rt (angle)


     Parameters: ‘angle’ – a number (integer or float)

     Turn turtle right by 'angle' units.  (Units are by default degrees,
     but can be set via the *note degrees(): 412c. and *note radians():
     412d. functions.)  Angle orientation depends on the turtle mode,
     see *note mode(): 416c.

          >>> turtle.heading()
          22.0
          >>> turtle.right(45)
          >>> turtle.heading()
          337.0

 -- Function: turtle.left (angle)
 -- Function: turtle.lt (angle)


     Parameters: ‘angle’ – a number (integer or float)

     Turn turtle left by 'angle' units.  (Units are by default degrees,
     but can be set via the *note degrees(): 412c. and *note radians():
     412d. functions.)  Angle orientation depends on the turtle mode,
     see *note mode(): 416c.

          >>> turtle.heading()
          22.0
          >>> turtle.left(45)
          >>> turtle.heading()
          67.0

 -- Function: turtle.goto (x, y=None)
 -- Function: turtle.setpos (x, y=None)
 -- Function: turtle.setposition (x, y=None)


     Parameters:

        * ‘x’ – a number or a pair/vector of numbers

        * ‘y’ – a number or ‘None’

     If 'y' is ‘None’, 'x' must be a pair of coordinates or a *note
     Vec2D: 417b. (e.g.  as returned by *note pos(): 4126.).

     Move turtle to an absolute position.  If the pen is down, draw
     line.  Do not change the turtle’s orientation.

          >>> tp = turtle.pos()
          >>> tp
          (0.00,0.00)
          >>> turtle.setpos(60,30)
          >>> turtle.pos()
          (60.00,30.00)
          >>> turtle.setpos((20,80))
          >>> turtle.pos()
          (20.00,80.00)
          >>> turtle.setpos(tp)
          >>> turtle.pos()
          (0.00,0.00)

 -- Function: turtle.teleport (x, y=None, *, fill_gap=False)


     Parameters:

        * ‘x’ – a number or ‘None’

        * ‘y’ – a number or ‘None’

        * ‘fill_gap’ – a boolean

     Move turtle to an absolute position.  Unlike goto(x, y), a line
     will not be drawn.  The turtle’s orientation does not change.  If
     currently filling, the polygon(s) teleported from will be filled
     after leaving, and filling will begin again after teleporting.
     This can be disabled with fill_gap=True, which makes the imaginary
     line traveled during teleporting act as a fill barrier like in
     goto(x, y).

          >>> tp = turtle.pos()
          >>> tp
          (0.00,0.00)
          >>> turtle.teleport(60)
          >>> turtle.pos()
          (60.00,0.00)
          >>> turtle.teleport(y=10)
          >>> turtle.pos()
          (60.00,10.00)
          >>> turtle.teleport(20, 30)
          >>> turtle.pos()
          (20.00,30.00)

     Added in version 3.12.

 -- Function: turtle.setx (x)


     Parameters: ‘x’ – a number (integer or float)

     Set the turtle’s first coordinate to 'x', leave second coordinate
     unchanged.

          >>> turtle.position()
          (0.00,240.00)
          >>> turtle.setx(10)
          >>> turtle.position()
          (10.00,240.00)

 -- Function: turtle.sety (y)


     Parameters: ‘y’ – a number (integer or float)

     Set the turtle’s second coordinate to 'y', leave first coordinate
     unchanged.

          >>> turtle.position()
          (0.00,40.00)
          >>> turtle.sety(-10)
          >>> turtle.position()
          (0.00,-10.00)

 -- Function: turtle.setheading (to_angle)
 -- Function: turtle.seth (to_angle)


     Parameters: ‘to_angle’ – a number (integer or float)

     Set the orientation of the turtle to 'to_angle'.  Here are some
     common directions in degrees:

     standard mode           logo mode
                             
     -------------------------------------------------
                             
     0 - east                0 - north
                             
                             
     90 - north              90 - east
                             
                             
     180 - west              180 - south
                             
                             
     270 - south             270 - west
                             

          >>> turtle.setheading(90)
          >>> turtle.heading()
          90.0

 -- Function: turtle.home ()

     Move turtle to the origin – coordinates (0,0) – and set its heading
     to its start-orientation (which depends on the mode, see *note
     mode(): 416c.).

          >>> turtle.heading()
          90.0
          >>> turtle.position()
          (0.00,-10.00)
          >>> turtle.home()
          >>> turtle.position()
          (0.00,0.00)
          >>> turtle.heading()
          0.0

 -- Function: turtle.circle (radius, extent=None, steps=None)


     Parameters:

        * ‘radius’ – a number

        * ‘extent’ – a number (or ‘None’)

        * ‘steps’ – an integer (or ‘None’)

     Draw a circle with given 'radius'.  The center is 'radius' units
     left of the turtle; 'extent' – an angle – determines which part of
     the circle is drawn.  If 'extent' is not given, draw the entire
     circle.  If 'extent' is not a full circle, one endpoint of the arc
     is the current pen position.  Draw the arc in counterclockwise
     direction if 'radius' is positive, otherwise in clockwise
     direction.  Finally the direction of the turtle is changed by the
     amount of 'extent'.

     As the circle is approximated by an inscribed regular polygon,
     'steps' determines the number of steps to use.  If not given, it
     will be calculated automatically.  May be used to draw regular
     polygons.

          >>> turtle.home()
          >>> turtle.position()
          (0.00,0.00)
          >>> turtle.heading()
          0.0
          >>> turtle.circle(50)
          >>> turtle.position()
          (-0.00,0.00)
          >>> turtle.heading()
          0.0
          >>> turtle.circle(120, 180)  # draw a semicircle
          >>> turtle.position()
          (0.00,240.00)
          >>> turtle.heading()
          180.0

 -- Function: turtle.dot ()

 -- Function: turtle.dot (size)

 -- Function: turtle.dot (color, /)

 -- Function: turtle.dot (size, color, /)

 -- Function: turtle.dot (size, r, g, b, /)


     Parameters:

        * ‘size’ – an integer >= 1 (if given)

        * ‘color’ – a colorstring or a numeric color tuple

     Draw a circular dot with diameter 'size', using 'color'.  If 'size'
     is not given, the maximum of ‘pensize+4’ and ‘2*pensize’ is used.

          >>> turtle.home()
          >>> turtle.dot()
          >>> turtle.fd(50); turtle.dot(20, "blue"); turtle.fd(50)
          >>> turtle.position()
          (100.00,-0.00)
          >>> turtle.heading()
          0.0

 -- Function: turtle.stamp ()

     Stamp a copy of the turtle shape onto the canvas at the current
     turtle position.  Return a stamp_id for that stamp, which can be
     used to delete it by calling ‘clearstamp(stamp_id)’.

          >>> turtle.color("blue")
          >>> stamp_id = turtle.stamp()
          >>> turtle.fd(50)

 -- Function: turtle.clearstamp (stampid)


     Parameters: ‘stampid’ – an integer, must be return value of
     previous *note stamp(): 4120. call

     Delete stamp with given 'stampid'.

          >>> turtle.position()
          (150.00,-0.00)
          >>> turtle.color("blue")
          >>> astamp = turtle.stamp()
          >>> turtle.fd(50)
          >>> turtle.position()
          (200.00,-0.00)
          >>> turtle.clearstamp(astamp)
          >>> turtle.position()
          (200.00,-0.00)

 -- Function: turtle.clearstamps (n=None)


     Parameters: ‘n’ – an integer (or ‘None’)

     Delete all or first/last 'n' of turtle’s stamps.  If 'n' is ‘None’,
     delete all stamps, if 'n' > 0 delete first 'n' stamps, else if 'n'
     < 0 delete last 'n' stamps.

          >>> for i in range(8):
          ...     unused_stamp_id = turtle.stamp()
          ...     turtle.fd(30)
          >>> turtle.clearstamps(2)
          >>> turtle.clearstamps(-2)
          >>> turtle.clearstamps()

 -- Function: turtle.undo ()

     Undo (repeatedly) the last turtle action(s).  Number of available
     undo actions is determined by the size of the undobuffer.

          >>> for i in range(4):
          ...     turtle.fd(50); turtle.lt(80)
          ...
          >>> for i in range(8):
          ...     turtle.undo()

 -- Function: turtle.speed (speed=None)


     Parameters: ‘speed’ – an integer in the range 0..10 or a
     speedstring (see below)

     Set the turtle’s speed to an integer value in the range 0..10.  If
     no argument is given, return current speed.

     If input is a number greater than 10 or smaller than 0.5, speed is
     set to 0.  Speedstrings are mapped to speedvalues as follows:

        * “fastest”: 0

        * “fast”: 10

        * “normal”: 6

        * “slow”: 3

        * “slowest”: 1

     Speeds from 1 to 10 enforce increasingly faster animation of line
     drawing and turtle turning.

     Attention: 'speed' = 0 means that 'no' animation takes place.
     forward/back makes turtle jump and likewise left/right make the
     turtle turn instantly.

          >>> turtle.speed()
          3
          >>> turtle.speed('normal')
          >>> turtle.speed()
          6
          >>> turtle.speed(9)
          >>> turtle.speed()
          9


File: python.info,  Node: Tell Turtle’s state,  Next: Settings for measurement,  Prev: Turtle motion,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.19 Tell Turtle’s state
..............................

 -- Function: turtle.position ()
 -- Function: turtle.pos ()

     Return the turtle’s current location (x,y) (as a *note Vec2D: 417b.
     vector).

          >>> turtle.pos()
          (440.00,-0.00)

 -- Function: turtle.towards (x, y=None)


     Parameters:

        * ‘x’ – a number or a pair/vector of numbers or a turtle
          instance

        * ‘y’ – a number if 'x' is a number, else ‘None’

     Return the angle between the line from turtle position to position
     specified by (x,y), the vector or the other turtle.  This depends
     on the turtle’s start orientation which depends on the mode -
     “standard”/”world” or “logo”.

          >>> turtle.goto(10, 10)
          >>> turtle.towards(0,0)
          225.0

 -- Function: turtle.xcor ()

     Return the turtle’s x coordinate.

          >>> turtle.home()
          >>> turtle.left(50)
          >>> turtle.forward(100)
          >>> turtle.pos()
          (64.28,76.60)
          >>> print(round(turtle.xcor(), 5))
          64.27876

 -- Function: turtle.ycor ()

     Return the turtle’s y coordinate.

          >>> turtle.home()
          >>> turtle.left(60)
          >>> turtle.forward(100)
          >>> print(turtle.pos())
          (50.00,86.60)
          >>> print(round(turtle.ycor(), 5))
          86.60254

 -- Function: turtle.heading ()

     Return the turtle’s current heading (value depends on the turtle
     mode, see *note mode(): 416c.).

          >>> turtle.home()
          >>> turtle.left(67)
          >>> turtle.heading()
          67.0

 -- Function: turtle.distance (x, y=None)


     Parameters:

        * ‘x’ – a number or a pair/vector of numbers or a turtle
          instance

        * ‘y’ – a number if 'x' is a number, else ‘None’

     Return the distance from the turtle to (x,y), the given vector, or
     the given other turtle, in turtle step units.

          >>> turtle.home()
          >>> turtle.distance(30,40)
          50.0
          >>> turtle.distance((30,40))
          50.0
          >>> joe = Turtle()
          >>> joe.forward(77)
          >>> turtle.distance(joe)
          77.0


File: python.info,  Node: Settings for measurement,  Next: Pen control<2>,  Prev: Tell Turtle’s state,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.20 Settings for measurement
...................................

 -- Function: turtle.degrees (fullcircle=360.0)


     Parameters: ‘fullcircle’ – a number

     Set angle measurement units, i.e.  set number of “degrees” for a
     full circle.  Default value is 360 degrees.

          >>> turtle.home()
          >>> turtle.left(90)
          >>> turtle.heading()
          90.0

          >>> # Change angle measurement unit to grad (also known as gon,
          >>> # grade, or gradian and equals 1/100-th of the right angle.)
          >>> turtle.degrees(400.0)
          >>> turtle.heading()
          100.0
          >>> turtle.degrees(360)
          >>> turtle.heading()
          90.0

 -- Function: turtle.radians ()

     Set the angle measurement units to radians.  Equivalent to
     ‘degrees(2*math.pi)’.

          >>> turtle.home()
          >>> turtle.left(90)
          >>> turtle.heading()
          90.0
          >>> turtle.radians()
          >>> turtle.heading()
          1.5707963267948966


File: python.info,  Node: Pen control<2>,  Next: Turtle state,  Prev: Settings for measurement,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.21 Pen control
......................

* Menu:

* Drawing state::
* Color control::
* Filling::
* More drawing control::


File: python.info,  Node: Drawing state,  Next: Color control,  Up: Pen control<2>

5.25.10.22 Drawing state
........................

 -- Function: turtle.pendown ()
 -- Function: turtle.pd ()
 -- Function: turtle.down ()

     Pull the pen down – drawing when moving.

 -- Function: turtle.penup ()
 -- Function: turtle.pu ()
 -- Function: turtle.up ()

     Pull the pen up – no drawing when moving.

 -- Function: turtle.pensize (width=None)
 -- Function: turtle.width (width=None)


     Parameters: ‘width’ – a positive number

     Set the line thickness to 'width' or return it.  If resizemode is
     set to “auto” and turtleshape is a polygon, that polygon is drawn
     with the same line thickness.  If no argument is given, the current
     pensize is returned.

          >>> turtle.pensize()
          1
          >>> turtle.pensize(10)   # from here on lines of width 10 are drawn

 -- Function: turtle.pen (pen=None, **pendict)


     Parameters:

        * ‘pen’ – a dictionary with some or all of the below listed keys

        * ‘pendict’ – one or more keyword-arguments with the below
          listed keys as keywords

     Return or set the pen’s attributes in a “pen-dictionary” with the
     following key/value pairs:

        * “shown”: True/False

        * “pendown”: True/False

        * “pencolor”: color-string or color-tuple

        * “fillcolor”: color-string or color-tuple

        * “pensize”: positive number

        * “speed”: number in range 0..10

        * “resizemode”: “auto” or “user” or “noresize”

        * “stretchfactor”: (positive number, positive number)

        * “outline”: positive number

        * “tilt”: number

     This dictionary can be used as argument for a subsequent call to
     ‘pen()’ to restore the former pen-state.  Moreover one or more of
     these attributes can be provided as keyword-arguments.  This can be
     used to set several pen attributes in one statement.

          >>> turtle.pen(fillcolor="black", pencolor="red", pensize=10)
          >>> sorted(turtle.pen().items())
          [('fillcolor', 'black'), ('outline', 1), ('pencolor', 'red'),
           ('pendown', True), ('pensize', 10), ('resizemode', 'noresize'),
           ('shearfactor', 0.0), ('shown', True), ('speed', 9),
           ('stretchfactor', (1.0, 1.0)), ('tilt', 0.0)]
          >>> penstate=turtle.pen()
          >>> turtle.color("yellow", "")
          >>> turtle.penup()
          >>> sorted(turtle.pen().items())[:3]
          [('fillcolor', ''), ('outline', 1), ('pencolor', 'yellow')]
          >>> turtle.pen(penstate, fillcolor="green")
          >>> sorted(turtle.pen().items())[:3]
          [('fillcolor', 'green'), ('outline', 1), ('pencolor', 'red')]

 -- Function: turtle.isdown ()

     Return ‘True’ if pen is down, ‘False’ if it’s up.

          >>> turtle.penup()
          >>> turtle.isdown()
          False
          >>> turtle.pendown()
          >>> turtle.isdown()
          True


File: python.info,  Node: Color control,  Next: Filling,  Prev: Drawing state,  Up: Pen control<2>

5.25.10.23 Color control
........................

 -- Function: turtle.pencolor ()

 -- Function: turtle.pencolor (color, /)

 -- Function: turtle.pencolor (r, g, b, /)

     Return or set the pencolor.

     Four input formats are allowed:

     ‘pencolor()’

          Return the current pencolor as color specification string or
          as a tuple (see example).  May be used as input to another
          color/pencolor/fillcolor/bgcolor call.

     ‘pencolor(colorstring)’

          Set pencolor to 'colorstring', which is a Tk color
          specification string, such as ‘"red"’, ‘"yellow"’, or
          ‘"#33cc8c"’.

     ‘pencolor((r, g, b))’

          Set pencolor to the RGB color represented by the tuple of 'r',
          'g', and 'b'.  Each of 'r', 'g', and 'b' must be in the range
          0..colormode, where colormode is either 1.0 or 255 (see *note
          colormode(): 416d.).

     ‘pencolor(r, g, b)’

          Set pencolor to the RGB color represented by 'r', 'g', and
          'b'.  Each of 'r', 'g', and 'b' must be in the range
          0..colormode.

     If turtleshape is a polygon, the outline of that polygon is drawn
     with the newly set pencolor.

          >>> colormode()
          1.0
          >>> turtle.pencolor()
          'red'
          >>> turtle.pencolor("brown")
          >>> turtle.pencolor()
          'brown'
          >>> tup = (0.2, 0.8, 0.55)
          >>> turtle.pencolor(tup)
          >>> turtle.pencolor()
          (0.2, 0.8, 0.5490196078431373)
          >>> colormode(255)
          >>> turtle.pencolor()
          (51.0, 204.0, 140.0)
          >>> turtle.pencolor('#32c18f')
          >>> turtle.pencolor()
          (50.0, 193.0, 143.0)

 -- Function: turtle.fillcolor ()

 -- Function: turtle.fillcolor (color, /)

 -- Function: turtle.fillcolor (r, g, b, /)

     Return or set the fillcolor.

     Four input formats are allowed:

     ‘fillcolor()’

          Return the current fillcolor as color specification string,
          possibly in tuple format (see example).  May be used as input
          to another color/pencolor/fillcolor/bgcolor call.

     ‘fillcolor(colorstring)’

          Set fillcolor to 'colorstring', which is a Tk color
          specification string, such as ‘"red"’, ‘"yellow"’, or
          ‘"#33cc8c"’.

     ‘fillcolor((r, g, b))’

          Set fillcolor to the RGB color represented by the tuple of
          'r', 'g', and 'b'.  Each of 'r', 'g', and 'b' must be in the
          range 0..colormode, where colormode is either 1.0 or 255 (see
          *note colormode(): 416d.).

     ‘fillcolor(r, g, b)’

          Set fillcolor to the RGB color represented by 'r', 'g', and
          'b'.  Each of 'r', 'g', and 'b' must be in the range
          0..colormode.

     If turtleshape is a polygon, the interior of that polygon is drawn
     with the newly set fillcolor.

          >>> turtle.fillcolor("violet")
          >>> turtle.fillcolor()
          'violet'
          >>> turtle.pencolor()
          (50.0, 193.0, 143.0)
          >>> turtle.fillcolor((50, 193, 143))  # Integers, not floats
          >>> turtle.fillcolor()
          (50.0, 193.0, 143.0)
          >>> turtle.fillcolor('#ffffff')
          >>> turtle.fillcolor()
          (255.0, 255.0, 255.0)

 -- Function: turtle.color ()

 -- Function: turtle.color (color, /)

 -- Function: turtle.color (r, g, b, /)

 -- Function: turtle.color (pencolor, fillcolor, /)

     Return or set pencolor and fillcolor.

     Several input formats are allowed.  They use 0 to 3 arguments as
     follows:

     ‘color()’

          Return the current pencolor and the current fillcolor as a
          pair of color specification strings or tuples as returned by
          *note pencolor(): 4139. and *note fillcolor(): 413a.

     ‘color(colorstring)’, ‘color((r,g,b))’, ‘color(r,g,b)’

          Inputs as in *note pencolor(): 4139, set both, fillcolor and
          pencolor, to the given value.

     ‘color(colorstring1, colorstring2)’, ‘color((r1,g1,b1), (r2,g2,b2))’

          Equivalent to ‘pencolor(colorstring1)’ and
          ‘fillcolor(colorstring2)’ and analogously if the other input
          format is used.

     If turtleshape is a polygon, outline and interior of that polygon
     is drawn with the newly set colors.

          >>> turtle.color("red", "green")
          >>> turtle.color()
          ('red', 'green')
          >>> color("#285078", "#a0c8f0")
          >>> color()
          ((40.0, 80.0, 120.0), (160.0, 200.0, 240.0))

See also: Screen method *note colormode(): 416d.


File: python.info,  Node: Filling,  Next: More drawing control,  Prev: Color control,  Up: Pen control<2>

5.25.10.24 Filling
..................

 -- Function: turtle.filling ()

     Return fillstate (‘True’ if filling, ‘False’ else).

          >>> turtle.begin_fill()
          >>> if turtle.filling():
          ...    turtle.pensize(5)
          ... else:
          ...    turtle.pensize(3)

 -- Function: turtle.begin_fill ()

     To be called just before drawing a shape to be filled.

 -- Function: turtle.end_fill ()

     Fill the shape drawn after the last call to *note begin_fill():
     413c.

     Whether or not overlap regions for self-intersecting polygons or
     multiple shapes are filled depends on the operating system
     graphics, type of overlap, and number of overlaps.  For example,
     the Turtle star above may be either all yellow or have some white
     regions.

          >>> turtle.color("black", "red")
          >>> turtle.begin_fill()
          >>> turtle.circle(80)
          >>> turtle.end_fill()


File: python.info,  Node: More drawing control,  Prev: Filling,  Up: Pen control<2>

5.25.10.25 More drawing control
...............................

 -- Function: turtle.reset ()

     Delete the turtle’s drawings from the screen, re-center the turtle
     and set variables to the default values.

          >>> turtle.goto(0,-22)
          >>> turtle.left(100)
          >>> turtle.position()
          (0.00,-22.00)
          >>> turtle.heading()
          100.0
          >>> turtle.reset()
          >>> turtle.position()
          (0.00,0.00)
          >>> turtle.heading()
          0.0

 -- Function: turtle.clear ()

     Delete the turtle’s drawings from the screen.  Do not move turtle.
     State and position of the turtle as well as drawings of other
     turtles are not affected.

 -- Function: turtle.write (arg, move=False, align='left',
          font=('Arial', 8, 'normal'))


     Parameters:

        * ‘arg’ – object to be written to the TurtleScreen

        * ‘move’ – True/False

        * ‘align’ – one of the strings “left”, “center” or right”

        * ‘font’ – a triple (fontname, fontsize, fonttype)

     Write text - the string representation of 'arg' - at the current
     turtle position according to 'align' (“left”, “center” or “right”)
     and with the given font.  If 'move' is true, the pen is moved to
     the bottom-right corner of the text.  By default, 'move' is
     ‘False’.

          >>> turtle.write("Home = ", True, align="center")
          >>> turtle.write((0,0), True)


File: python.info,  Node: Turtle state,  Next: Using events,  Prev: Pen control<2>,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.26 Turtle state
.......................

* Menu:

* Visibility::
* Appearance::


File: python.info,  Node: Visibility,  Next: Appearance,  Up: Turtle state

5.25.10.27 Visibility
.....................

 -- Function: turtle.hideturtle ()
 -- Function: turtle.ht ()

     Make the turtle invisible.  It’s a good idea to do this while
     you’re in the middle of doing some complex drawing, because hiding
     the turtle speeds up the drawing observably.

          >>> turtle.hideturtle()

 -- Function: turtle.showturtle ()
 -- Function: turtle.st ()

     Make the turtle visible.

          >>> turtle.showturtle()

 -- Function: turtle.isvisible ()

     Return ‘True’ if the Turtle is shown, ‘False’ if it’s hidden.

          >>> turtle.hideturtle()
          >>> turtle.isvisible()
          False
          >>> turtle.showturtle()
          >>> turtle.isvisible()
          True


File: python.info,  Node: Appearance,  Prev: Visibility,  Up: Turtle state

5.25.10.28 Appearance
.....................

 -- Function: turtle.shape (name=None)


     Parameters: ‘name’ – a string which is a valid shapename

     Set turtle shape to shape with given 'name' or, if name is not
     given, return name of current shape.  Shape with 'name' must exist
     in the TurtleScreen’s shape dictionary.  Initially there are the
     following polygon shapes: “arrow”, “turtle”, “circle”, “square”,
     “triangle”, “classic”.  To learn about how to deal with shapes see
     Screen method *note register_shape(): 4170.

          >>> turtle.shape()
          'classic'
          >>> turtle.shape("turtle")
          >>> turtle.shape()
          'turtle'

 -- Function: turtle.resizemode (rmode=None)


     Parameters: ‘rmode’ – one of the strings “auto”, “user”, “noresize”

     Set resizemode to one of the values: “auto”, “user”, “noresize”.
     If 'rmode' is not given, return current resizemode.  Different
     resizemodes have the following effects:

        - “auto”: adapts the appearance of the turtle corresponding to
          the value of pensize.

        - “user”: adapts the appearance of the turtle according to the
          values of stretchfactor and outlinewidth (outline), which are
          set by *note shapesize(): 4148.

        - “noresize”: no adaption of the turtle’s appearance takes
          place.

     ‘resizemode("user")’ is called by *note shapesize(): 4148. when
     used with arguments.

          >>> turtle.resizemode()
          'noresize'
          >>> turtle.resizemode("auto")
          >>> turtle.resizemode()
          'auto'

 -- Function: turtle.shapesize (stretch_wid=None, stretch_len=None,
          outline=None)
 -- Function: turtle.turtlesize (stretch_wid=None, stretch_len=None,
          outline=None)


     Parameters:

        * ‘stretch_wid’ – positive number

        * ‘stretch_len’ – positive number

        * ‘outline’ – positive number

     Return or set the pen’s attributes x/y-stretchfactors and/or
     outline.  Set resizemode to “user”.  If and only if resizemode is
     set to “user”, the turtle will be displayed stretched according to
     its stretchfactors: 'stretch_wid' is stretchfactor perpendicular to
     its orientation, 'stretch_len' is stretchfactor in direction of its
     orientation, 'outline' determines the width of the shape’s outline.

          >>> turtle.shapesize()
          (1.0, 1.0, 1)
          >>> turtle.resizemode("user")
          >>> turtle.shapesize(5, 5, 12)
          >>> turtle.shapesize()
          (5, 5, 12)
          >>> turtle.shapesize(outline=8)
          >>> turtle.shapesize()
          (5, 5, 8)

 -- Function: turtle.shearfactor (shear=None)


     Parameters: ‘shear’ – number (optional)

     Set or return the current shearfactor.  Shear the turtleshape
     according to the given shearfactor shear, which is the tangent of
     the shear angle.  Do 'not' change the turtle’s heading (direction
     of movement).  If shear is not given: return the current
     shearfactor, i.  e.  the tangent of the shear angle, by which lines
     parallel to the heading of the turtle are sheared.

          >>> turtle.shape("circle")
          >>> turtle.shapesize(5,2)
          >>> turtle.shearfactor(0.5)
          >>> turtle.shearfactor()
          0.5

 -- Function: turtle.tilt (angle)


     Parameters: ‘angle’ – a number

     Rotate the turtleshape by 'angle' from its current tilt-angle, but
     do 'not' change the turtle’s heading (direction of movement).

          >>> turtle.reset()
          >>> turtle.shape("circle")
          >>> turtle.shapesize(5,2)
          >>> turtle.tilt(30)
          >>> turtle.fd(50)
          >>> turtle.tilt(30)
          >>> turtle.fd(50)

 -- Function: turtle.tiltangle (angle=None)


     Parameters: ‘angle’ – a number (optional)

     Set or return the current tilt-angle.  If angle is given, rotate
     the turtleshape to point in the direction specified by angle,
     regardless of its current tilt-angle.  Do 'not' change the turtle’s
     heading (direction of movement).  If angle is not given: return the
     current tilt-angle, i.  e.  the angle between the orientation of
     the turtleshape and the heading of the turtle (its direction of
     movement).

          >>> turtle.reset()
          >>> turtle.shape("circle")
          >>> turtle.shapesize(5,2)
          >>> turtle.tilt(45)
          >>> turtle.tiltangle()
          45.0

 -- Function: turtle.shapetransform (t11=None, t12=None, t21=None,
          t22=None)


     Parameters:

        * ‘t11’ – a number (optional)

        * ‘t12’ – a number (optional)

        * ‘t21’ – a number (optional)

        * ‘t12’ – a number (optional)

     Set or return the current transformation matrix of the turtle
     shape.

     If none of the matrix elements are given, return the transformation
     matrix as a tuple of 4 elements.  Otherwise set the given elements
     and transform the turtleshape according to the matrix consisting of
     first row t11, t12 and second row t21, t22.  The determinant t11 *
     t22 - t12 * t21 must not be zero, otherwise an error is raised.
     Modify stretchfactor, shearfactor and tiltangle according to the
     given matrix.

          >>> turtle = Turtle()
          >>> turtle.shape("square")
          >>> turtle.shapesize(4,2)
          >>> turtle.shearfactor(-0.5)
          >>> turtle.shapetransform()
          (4.0, -1.0, -0.0, 2.0)

 -- Function: turtle.get_shapepoly ()

     Return the current shape polygon as tuple of coordinate pairs.
     This can be used to define a new shape or components of a compound
     shape.

          >>> turtle.shape("square")
          >>> turtle.shapetransform(4, -1, 0, 2)
          >>> turtle.get_shapepoly()
          ((50, -20), (30, 20), (-50, 20), (-30, -20))


File: python.info,  Node: Using events,  Next: Special Turtle methods,  Prev: Turtle state,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.29 Using events
.......................

 -- Function: turtle.onclick (fun, btn=1, add=None)


     Parameters:

        * ‘fun’ – a function with two arguments which will be called
          with the coordinates of the clicked point on the canvas

        * ‘btn’ – number of the mouse-button, defaults to 1 (left mouse
          button)

        * ‘add’ – ‘True’ or ‘False’ – if ‘True’, a new binding will be
          added, otherwise it will replace a former binding

     Bind 'fun' to mouse-click events on this turtle.  If 'fun' is
     ‘None’, existing bindings are removed.  Example for the anonymous
     turtle, i.e.  the procedural way:

          >>> def turn(x, y):
          ...     left(180)
          ...
          >>> onclick(turn)  # Now clicking into the turtle will turn it.
          >>> onclick(None)  # event-binding will be removed

 -- Function: turtle.onrelease (fun, btn=1, add=None)


     Parameters:

        * ‘fun’ – a function with two arguments which will be called
          with the coordinates of the clicked point on the canvas

        * ‘btn’ – number of the mouse-button, defaults to 1 (left mouse
          button)

        * ‘add’ – ‘True’ or ‘False’ – if ‘True’, a new binding will be
          added, otherwise it will replace a former binding

     Bind 'fun' to mouse-button-release events on this turtle.  If 'fun'
     is ‘None’, existing bindings are removed.

          >>> class MyTurtle(Turtle):
          ...     def glow(self,x,y):
          ...         self.fillcolor("red")
          ...     def unglow(self,x,y):
          ...         self.fillcolor("")
          ...
          >>> turtle = MyTurtle()
          >>> turtle.onclick(turtle.glow)     # clicking on turtle turns fillcolor red,
          >>> turtle.onrelease(turtle.unglow) # releasing turns it to transparent.

 -- Function: turtle.ondrag (fun, btn=1, add=None)


     Parameters:

        * ‘fun’ – a function with two arguments which will be called
          with the coordinates of the clicked point on the canvas

        * ‘btn’ – number of the mouse-button, defaults to 1 (left mouse
          button)

        * ‘add’ – ‘True’ or ‘False’ – if ‘True’, a new binding will be
          added, otherwise it will replace a former binding

     Bind 'fun' to mouse-move events on this turtle.  If 'fun' is
     ‘None’, existing bindings are removed.

     Remark: Every sequence of mouse-move-events on a turtle is preceded
     by a mouse-click event on that turtle.

          >>> turtle.ondrag(turtle.goto)

     Subsequently, clicking and dragging the Turtle will move it across
     the screen thereby producing handdrawings (if pen is down).


File: python.info,  Node: Special Turtle methods,  Next: Compound shapes,  Prev: Using events,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.30 Special Turtle methods
.................................

 -- Function: turtle.begin_poly ()

     Start recording the vertices of a polygon.  Current turtle position
     is first vertex of polygon.

 -- Function: turtle.end_poly ()

     Stop recording the vertices of a polygon.  Current turtle position
     is last vertex of polygon.  This will be connected with the first
     vertex.

 -- Function: turtle.get_poly ()

     Return the last recorded polygon.

          >>> turtle.home()
          >>> turtle.begin_poly()
          >>> turtle.fd(100)
          >>> turtle.left(20)
          >>> turtle.fd(30)
          >>> turtle.left(60)
          >>> turtle.fd(50)
          >>> turtle.end_poly()
          >>> p = turtle.get_poly()
          >>> register_shape("myFavouriteShape", p)

 -- Function: turtle.clone ()

     Create and return a clone of the turtle with same position, heading
     and turtle properties.

          >>> mick = Turtle()
          >>> joe = mick.clone()

 -- Function: turtle.getturtle ()
 -- Function: turtle.getpen ()

     Return the Turtle object itself.  Only reasonable use: as a
     function to return the “anonymous turtle”:

          >>> pet = getturtle()
          >>> pet.fd(50)
          >>> pet
          <turtle.Turtle object at 0x...>

 -- Function: turtle.getscreen ()

     Return the *note TurtleScreen: 4188. object the turtle is drawing
     on.  TurtleScreen methods can then be called for that object.

          >>> ts = turtle.getscreen()
          >>> ts
          <turtle._Screen object at 0x...>
          >>> ts.bgcolor("pink")

 -- Function: turtle.setundobuffer (size)


     Parameters: ‘size’ – an integer or ‘None’

     Set or disable undobuffer.  If 'size' is an integer, an empty
     undobuffer of given size is installed.  'size' gives the maximum
     number of turtle actions that can be undone by the *note undo():
     4123. method/function.  If 'size' is ‘None’, the undobuffer is
     disabled.

          >>> turtle.setundobuffer(42)

 -- Function: turtle.undobufferentries ()

     Return number of entries in the undobuffer.

          >>> while undobufferentries():
          ...     undo()


File: python.info,  Node: Compound shapes,  Prev: Special Turtle methods,  Up: Methods of RawTurtle/Turtle and corresponding functions

5.25.10.31 Compound shapes
..........................

To use compound turtle shapes, which consist of several polygons of
different color, you must use the helper class *note Shape: 418b.
explicitly as described below:

  1. Create an empty Shape object of type “compound”.

  2. Add as many components to this object as desired, using the *note
     addcomponent(): 418c. method.

     For example:

          >>> s = Shape("compound")
          >>> poly1 = ((0,0),(10,-5),(0,10),(-10,-5))
          >>> s.addcomponent(poly1, "red", "blue")
          >>> poly2 = ((0,0),(10,-5),(-10,-5))
          >>> s.addcomponent(poly2, "blue", "red")

  3. Now add the Shape to the Screen’s shapelist and use it:

          >>> register_shape("myshape", s)
          >>> shape("myshape")

     Note: The *note Shape: 418b. class is used internally by the *note
     register_shape(): 4170. method in different ways.  The application
     programmer has to deal with the Shape class 'only' when using
     compound shapes like shown above!


File: python.info,  Node: Methods of TurtleScreen/Screen and corresponding functions,  Next: Public classes,  Prev: Methods of RawTurtle/Turtle and corresponding functions,  Up: turtle — Turtle graphics

5.25.10.32 Methods of TurtleScreen/Screen and corresponding functions
.....................................................................

Most of the examples in this section refer to a TurtleScreen instance
called ‘screen’.

* Menu:

* Window control::
* Animation control::
* Using screen events::
* Input methods::
* Settings and special methods::
* Methods specific to Screen, not inherited from TurtleScreen: Methods specific to Screen not inherited from TurtleScreen.


File: python.info,  Node: Window control,  Next: Animation control,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.33 Window control
.........................

 -- Function: turtle.bgcolor ()

 -- Function: turtle.bgcolor (color, /)

 -- Function: turtle.bgcolor (r, g, b, /)

     Return or set the background color of the TurtleScreen.

     Four input formats are allowed:

     ‘bgcolor()’

          Return the current background color as color specification
          string or as a tuple (see example).  May be used as input to
          another color/pencolor/fillcolor/bgcolor call.

     ‘bgcolor(colorstring)’

          Set the background color to 'colorstring', which is a Tk color
          specification string, such as ‘"red"’, ‘"yellow"’, or
          ‘"#33cc8c"’.

     ‘bgcolor((r, g, b))’

          Set the background color to the RGB color represented by the
          tuple of 'r', 'g', and 'b'.  Each of 'r', 'g', and 'b' must be
          in the range 0..colormode, where colormode is either 1.0 or
          255 (see *note colormode(): 416d.).

     ‘bgcolor(r, g, b)’

          Set the background color to the RGB color represented by 'r',
          'g', and 'b'.  Each of 'r', 'g', and 'b' must be in the range
          0..colormode.

          >>> screen.bgcolor("orange")
          >>> screen.bgcolor()
          'orange'
          >>> screen.bgcolor("#800080")
          >>> screen.bgcolor()
          (128.0, 0.0, 128.0)

 -- Function: turtle.bgpic (picname=None)


     Parameters: ‘picname’ – a string, name of a gif-file or ‘"nopic"’,
     or ‘None’

     Set background image or return name of current backgroundimage.  If
     'picname' is a filename, set the corresponding image as background.
     If 'picname' is ‘"nopic"’, delete background image, if present.  If
     'picname' is ‘None’, return the filename of the current
     backgroundimage.

          >>> screen.bgpic()
          'nopic'
          >>> screen.bgpic("landscape.gif")
          >>> screen.bgpic()
          "landscape.gif"

 -- Function: turtle.clear ()

          Note: This TurtleScreen method is available as a global
          function only under the name ‘clearscreen’.  The global
          function ‘clear’ is a different one derived from the Turtle
          method ‘clear’.

 -- Function: turtle.clearscreen ()

     Delete all drawings and all turtles from the TurtleScreen.  Reset
     the now empty TurtleScreen to its initial state: white background,
     no background image, no event bindings and tracing on.

 -- Function: turtle.reset ()

          Note: This TurtleScreen method is available as a global
          function only under the name ‘resetscreen’.  The global
          function ‘reset’ is another one derived from the Turtle method
          ‘reset’.

 -- Function: turtle.resetscreen ()

     Reset all Turtles on the Screen to their initial state.

 -- Function: turtle.screensize (canvwidth=None, canvheight=None,
          bg=None)


     Parameters:

        * ‘canvwidth’ – positive integer, new width of canvas in pixels

        * ‘canvheight’ – positive integer, new height of canvas in
          pixels

        * ‘bg’ – colorstring or color-tuple, new background color

     If no arguments are given, return current (canvaswidth,
     canvasheight).  Else resize the canvas the turtles are drawing on.
     Do not alter the drawing window.  To observe hidden parts of the
     canvas, use the scrollbars.  With this method, one can make visible
     those parts of a drawing which were outside the canvas before.

          >>> screen.screensize()
          (400, 300)
          >>> screen.screensize(2000,1500)
          >>> screen.screensize()
          (2000, 1500)

     e.g.  to search for an erroneously escaped turtle ;-)

 -- Function: turtle.setworldcoordinates (llx, lly, urx, ury)


     Parameters:

        * ‘llx’ – a number, x-coordinate of lower left corner of canvas

        * ‘lly’ – a number, y-coordinate of lower left corner of canvas

        * ‘urx’ – a number, x-coordinate of upper right corner of canvas

        * ‘ury’ – a number, y-coordinate of upper right corner of canvas

     Set up user-defined coordinate system and switch to mode “world” if
     necessary.  This performs a ‘screen.reset()’.  If mode “world” is
     already active, all drawings are redrawn according to the new
     coordinates.

     'ATTENTION': in user-defined coordinate systems angles may appear
     distorted.

          >>> screen.reset()
          >>> screen.setworldcoordinates(-50,-7.5,50,7.5)
          >>> for _ in range(72):
          ...     left(10)
          ...
          >>> for _ in range(8):
          ...     left(45); fd(2)   # a regular octagon


File: python.info,  Node: Animation control,  Next: Using screen events,  Prev: Window control,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.34 Animation control
............................

 -- Function: turtle.delay (delay=None)


     Parameters: ‘delay’ – positive integer

     Set or return the drawing 'delay' in milliseconds.  (This is
     approximately the time interval between two consecutive canvas
     updates.)  The longer the drawing delay, the slower the animation.

     Optional argument:

          >>> screen.delay()
          10
          >>> screen.delay(5)
          >>> screen.delay()
          5

 -- Function: turtle.tracer (n=None, delay=None)


     Parameters:

        * ‘n’ – nonnegative integer

        * ‘delay’ – nonnegative integer

     Turn turtle animation on/off and set delay for update drawings.  If
     'n' is given, only each n-th regular screen update is really
     performed.  (Can be used to accelerate the drawing of complex
     graphics.)  When called without arguments, returns the currently
     stored value of n.  Second argument sets delay value (see *note
     delay(): 4161.).

          >>> screen.tracer(8, 25)
          >>> dist = 2
          >>> for i in range(200):
          ...     fd(dist)
          ...     rt(90)
          ...     dist += 2

 -- Function: turtle.update ()

     Perform a TurtleScreen update.  To be used when tracer is turned
     off.

See also the RawTurtle/Turtle method *note speed(): 4124.


File: python.info,  Node: Using screen events,  Next: Input methods,  Prev: Animation control,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.35 Using screen events
..............................

 -- Function: turtle.listen (xdummy=None, ydummy=None)

     Set focus on TurtleScreen (in order to collect key-events).  Dummy
     arguments are provided in order to be able to pass ‘listen()’ to
     the onclick method.

 -- Function: turtle.onkey (fun, key)
 -- Function: turtle.onkeyrelease (fun, key)


     Parameters:

        * ‘fun’ – a function with no arguments or ‘None’

        * ‘key’ – a string: key (e.g.  “a”) or key-symbol (e.g.
          “space”)

     Bind 'fun' to key-release event of key.  If 'fun' is ‘None’, event
     bindings are removed.  Remark: in order to be able to register
     key-events, TurtleScreen must have the focus.  (See method *note
     listen(): 4164.)

          >>> def f():
          ...     fd(50)
          ...     lt(60)
          ...
          >>> screen.onkey(f, "Up")
          >>> screen.listen()

 -- Function: turtle.onkeypress (fun, key=None)


     Parameters:

        * ‘fun’ – a function with no arguments or ‘None’

        * ‘key’ – a string: key (e.g.  “a”) or key-symbol (e.g.
          “space”)

     Bind 'fun' to key-press event of key if key is given, or to any
     key-press-event if no key is given.  Remark: in order to be able to
     register key-events, TurtleScreen must have focus.  (See method
     *note listen(): 4164.)

          >>> def f():
          ...     fd(50)
          ...
          >>> screen.onkey(f, "Up")
          >>> screen.listen()

 -- Function: turtle.onclick (fun, btn=1, add=None)
 -- Function: turtle.onscreenclick (fun, btn=1, add=None)


     Parameters:

        * ‘fun’ – a function with two arguments which will be called
          with the coordinates of the clicked point on the canvas

        * ‘btn’ – number of the mouse-button, defaults to 1 (left mouse
          button)

        * ‘add’ – ‘True’ or ‘False’ – if ‘True’, a new binding will be
          added, otherwise it will replace a former binding

     Bind 'fun' to mouse-click events on this screen.  If 'fun' is
     ‘None’, existing bindings are removed.

     Example for a TurtleScreen instance named ‘screen’ and a Turtle
     instance named ‘turtle’:

          >>> screen.onclick(turtle.goto) # Subsequently clicking into the TurtleScreen will
          >>>                             # make the turtle move to the clicked point.
          >>> screen.onclick(None)        # remove event binding again

          Note: This TurtleScreen method is available as a global
          function only under the name ‘onscreenclick’.  The global
          function ‘onclick’ is another one derived from the Turtle
          method ‘onclick’.

 -- Function: turtle.ontimer (fun, t=0)


     Parameters:

        * ‘fun’ – a function with no arguments

        * ‘t’ – a number >= 0

     Install a timer that calls 'fun' after 't' milliseconds.

          >>> running = True
          >>> def f():
          ...     if running:
          ...         fd(50)
          ...         lt(60)
          ...         screen.ontimer(f, 250)
          >>> f()   ### makes the turtle march around
          >>> running = False

 -- Function: turtle.mainloop ()
 -- Function: turtle.done ()

     Starts event loop - calling Tkinter’s mainloop function.  Must be
     the last statement in a turtle graphics program.  Must 'not' be
     used if a script is run from within IDLE in -n mode (No subprocess)
     - for interactive use of turtle graphics.

          >>> screen.mainloop()


File: python.info,  Node: Input methods,  Next: Settings and special methods,  Prev: Using screen events,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.36 Input methods
........................

 -- Function: turtle.textinput (title, prompt)


     Parameters:

        * ‘title’ – string

        * ‘prompt’ – string

     Pop up a dialog window for input of a string.  Parameter title is
     the title of the dialog window, prompt is a text mostly describing
     what information to input.  Return the string input.  If the dialog
     is canceled, return ‘None’.

          >>> screen.textinput("NIM", "Name of first player:")

 -- Function: turtle.numinput (title, prompt, default=None, minval=None,
          maxval=None)


     Parameters:

        * ‘title’ – string

        * ‘prompt’ – string

        * ‘default’ – number (optional)

        * ‘minval’ – number (optional)

        * ‘maxval’ – number (optional)

     Pop up a dialog window for input of a number.  title is the title
     of the dialog window, prompt is a text mostly describing what
     numerical information to input.  default: default value, minval:
     minimum value for input, maxval: maximum value for input.  The
     number input must be in the range minval ..  maxval if these are
     given.  If not, a hint is issued and the dialog remains open for
     correction.  Return the number input.  If the dialog is canceled,
     return ‘None’.

          >>> screen.numinput("Poker", "Your stakes:", 1000, minval=10, maxval=10000)


File: python.info,  Node: Settings and special methods,  Next: Methods specific to Screen not inherited from TurtleScreen,  Prev: Input methods,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.37 Settings and special methods
.......................................

 -- Function: turtle.mode (mode=None)


     Parameters: ‘mode’ – one of the strings “standard”, “logo” or
     “world”

     Set turtle mode (“standard”, “logo” or “world”) and perform reset.
     If mode is not given, current mode is returned.

     Mode “standard” is compatible with old ‘turtle’.  Mode “logo” is
     compatible with most Logo turtle graphics.  Mode “world” uses
     user-defined “world coordinates”.  'Attention': in this mode angles
     appear distorted if ‘x/y’ unit-ratio doesn’t equal 1.

     Mode             Initial turtle heading        positive angles
                                                    
     -----------------------------------------------------------------------
                                                    
     “standard”       to the right (east)           counterclockwise
                                                    
                                                    
     “logo”           upward (north)                clockwise
                                                    

          >>> mode("logo")   # resets turtle heading to north
          >>> mode()
          'logo'

 -- Function: turtle.colormode (cmode=None)


     Parameters: ‘cmode’ – one of the values 1.0 or 255

     Return the colormode or set it to 1.0 or 255.  Subsequently 'r',
     'g', 'b' values of color triples have to be in the range
     0..*cmode*.

          >>> screen.colormode(1)
          >>> turtle.pencolor(240, 160, 80)
          Traceback (most recent call last):
               ...
          TurtleGraphicsError: bad color sequence: (240, 160, 80)
          >>> screen.colormode()
          1.0
          >>> screen.colormode(255)
          >>> screen.colormode()
          255
          >>> turtle.pencolor(240,160,80)

 -- Function: turtle.getcanvas ()

     Return the Canvas of this TurtleScreen.  Useful for insiders who
     know what to do with a Tkinter Canvas.

          >>> cv = screen.getcanvas()
          >>> cv
          <turtle.ScrolledCanvas object ...>

 -- Function: turtle.getshapes ()

     Return a list of names of all currently available turtle shapes.

          >>> screen.getshapes()
          ['arrow', 'blank', 'circle', ..., 'turtle']

 -- Function: turtle.register_shape (name, shape=None)
 -- Function: turtle.addshape (name, shape=None)

     There are three different ways to call this function:

       1. 'name' is the name of a gif-file and 'shape' is ‘None’:
          Install the corresponding image shape.

               >>> screen.register_shape("turtle.gif")

               Note: Image shapes 'do not' rotate when turning the
               turtle, so they do not display the heading of the turtle!

       2. 'name' is an arbitrary string and 'shape' is a tuple of pairs
          of coordinates: Install the corresponding polygon shape.

               >>> screen.register_shape("triangle", ((5,-3), (0,5), (-5,-3)))

       3. 'name' is an arbitrary string and 'shape' is a (compound)
          *note Shape: 418b. object: Install the corresponding compound
          shape.

     Add a turtle shape to TurtleScreen’s shapelist.  Only thusly
     registered shapes can be used by issuing the command
     ‘shape(shapename)’.

 -- Function: turtle.turtles ()

     Return the list of turtles on the screen.

          >>> for turtle in screen.turtles():
          ...     turtle.color("red")

 -- Function: turtle.window_height ()

     Return the height of the turtle window.

          >>> screen.window_height()
          480

 -- Function: turtle.window_width ()

     Return the width of the turtle window.

          >>> screen.window_width()
          640


File: python.info,  Node: Methods specific to Screen not inherited from TurtleScreen,  Prev: Settings and special methods,  Up: Methods of TurtleScreen/Screen and corresponding functions

5.25.10.38 Methods specific to Screen, not inherited from TurtleScreen
......................................................................

 -- Function: turtle.bye ()

     Shut the turtlegraphics window.

 -- Function: turtle.exitonclick ()

     Bind ‘bye()’ method to mouse clicks on the Screen.

     If the value “using_IDLE” in the configuration dictionary is
     ‘False’ (default value), also enter mainloop.  Remark: If IDLE with
     the ‘-n’ switch (no subprocess) is used, this value should be set
     to ‘True’ in ‘turtle.cfg’.  In this case IDLE’s own mainloop is
     active also for the client script.

 -- Function: turtle.setup (width=_CFG['width'], height=_CFG['height'],
          startx=_CFG['leftright'], starty=_CFG['topbottom'])

     Set the size and position of the main window.  Default values of
     arguments are stored in the configuration dictionary and can be
     changed via a ‘turtle.cfg’ file.


     Parameters:

        * ‘width’ – if an integer, a size in pixels, if a float, a
          fraction of the screen; default is 50% of screen

        * ‘height’ – if an integer, the height in pixels, if a float, a
          fraction of the screen; default is 75% of screen

        * ‘startx’ – if positive, starting position in pixels from the
          left edge of the screen, if negative from the right edge, if
          ‘None’, center window horizontally

        * ‘starty’ – if positive, starting position in pixels from the
          top edge of the screen, if negative from the bottom edge, if
          ‘None’, center window vertically

          >>> screen.setup (width=200, height=200, startx=0, starty=0)
          >>>              # sets window to 200x200 pixels, in upper left of screen
          >>> screen.setup(width=.75, height=0.5, startx=None, starty=None)
          >>>              # sets window to 75% of screen by 50% of screen and centers

 -- Function: turtle.title (titlestring)


     Parameters: ‘titlestring’ – a string that is shown in the titlebar
     of the turtle graphics window

     Set title of turtle window to 'titlestring'.

          >>> screen.title("Welcome to the turtle zoo!")


File: python.info,  Node: Public classes,  Next: Explanation<2>,  Prev: Methods of TurtleScreen/Screen and corresponding functions,  Up: turtle — Turtle graphics

5.25.10.39 Public classes
.........................

 -- Class: turtle.RawTurtle (canvas)
 -- Class: turtle.RawPen (canvas)


     Parameters: ‘canvas’ – a ‘tkinter.Canvas’, a *note ScrolledCanvas:
     4198. or a *note TurtleScreen: 4188.

     Create a turtle.  The turtle has all methods described above as
     “methods of Turtle/RawTurtle”.

 -- Class: turtle.Turtle

     Subclass of RawTurtle, has the same interface but draws on a
     default *note Screen: 410b. object created automatically when
     needed for the first time.

 -- Class: turtle.TurtleScreen (cv)


     Parameters: ‘cv’ – a ‘tkinter.Canvas’

     Provides screen oriented methods like *note bgcolor(): 415b. etc.
     that are described above.

 -- Class: turtle.Screen

     Subclass of TurtleScreen, with *note four methods added: 4194.

 -- Class: turtle.ScrolledCanvas (master)


     Parameters: ‘master’ – some Tkinter widget to contain the
     ScrolledCanvas, i.e.  a Tkinter-canvas with scrollbars added

     Used by class Screen, which thus automatically provides a
     ScrolledCanvas as playground for the turtles.

 -- Class: turtle.Shape (type_, data)


     Parameters: ‘type_’ – one of the strings “polygon”, “image”,
     “compound”

     Data structure modeling shapes.  The pair ‘(type_, data)’ must
     follow this specification:

     'type_'         'data'
                     
     -------------------------------------------------------------------------------
                     
     “polygon”       a polygon-tuple, i.e.  a tuple of pairs of coordinates
                     
                     
     “image”         an image (in this form only used internally!)
                     
                     
     “compound”      ‘None’ (a compound shape has to be constructed using the
                     *note addcomponent(): 418c. method)
                     

      -- Method: addcomponent (poly, fill, outline=None)


          Parameters:

             * ‘poly’ – a polygon, i.e.  a tuple of pairs of numbers

             * ‘fill’ – a color the 'poly' will be filled with

             * ‘outline’ – a color for the poly’s outline (if given)

          Example:

               >>> poly = ((0,0),(10,-5),(0,10),(-10,-5))
               >>> s = Shape("compound")
               >>> s.addcomponent(poly, "red", "blue")
               >>> # ... add more components and then use register_shape()

          See *note Compound shapes: 418a.

 -- Class: turtle.Vec2D (x, y)

     A two-dimensional vector class, used as a helper class for
     implementing turtle graphics.  May be useful for turtle graphics
     programs too.  Derived from tuple, so a vector is a tuple!

     Provides (for 'a', 'b' vectors, 'k' number):

        * ‘a + b’ vector addition

        * ‘a - b’ vector subtraction

        * ‘a * b’ inner product

        * ‘k * a’ and ‘a * k’ multiplication with scalar

        * ‘abs(a)’ absolute value of a

        * ‘a.rotate(angle)’ rotation


File: python.info,  Node: Explanation<2>,  Next: Help and configuration,  Prev: Public classes,  Up: turtle — Turtle graphics

5.25.10.40 Explanation
......................

A turtle object draws on a screen object, and there a number of key
classes in the turtle object-oriented interface that can be used to
create them and relate them to each other.

A *note Turtle: 4199. instance will automatically create a *note Screen:
410b. instance if one is not already present.

‘Turtle’ is a subclass of *note RawTurtle: 4196, which 'doesn’t'
automatically create a drawing surface - a 'canvas' will need to be
provided or created for it.  The 'canvas' can be a ‘tkinter.Canvas’,
*note ScrolledCanvas: 4198. or *note TurtleScreen: 4188.

*note TurtleScreen: 4188. is the basic drawing surface for a turtle.
*note Screen: 410b. is a subclass of ‘TurtleScreen’, and includes *note
some additional methods: 4194. for managing its appearance (including
size and title) and behaviour.  ‘TurtleScreen’’s constructor needs a
‘tkinter.Canvas’ or a *note ScrolledCanvas: 4198. as an argument.

The functional interface for turtle graphics uses the various methods of
‘Turtle’ and ‘TurtleScreen’/‘Screen’.  Behind the scenes, a screen
object is automatically created whenever a function derived from a
‘Screen’ method is called.  Similarly, a turtle object is automatically
created whenever any of the functions derived from a Turtle method is
called.

To use multiple turtles on a screen, the object-oriented interface must
be used.


File: python.info,  Node: Help and configuration,  Next: turtledemo — Demo scripts,  Prev: Explanation<2>,  Up: turtle — Turtle graphics

5.25.10.41 Help and configuration
.................................

* Menu:

* How to use help::
* Translation of docstrings into different languages::
* How to configure Screen and Turtles::


File: python.info,  Node: How to use help,  Next: Translation of docstrings into different languages,  Up: Help and configuration

5.25.10.42 How to use help
..........................

The public methods of the Screen and Turtle classes are documented
extensively via docstrings.  So these can be used as online-help via the
Python help facilities:

   - When using IDLE, tooltips show the signatures and first lines of
     the docstrings of typed in function-/method calls.

   - Calling *note help(): 8e0. on methods or functions displays the
     docstrings:

          >>> help(Screen.bgcolor)
          Help on method bgcolor in module turtle:

          bgcolor(self, *args) unbound turtle.Screen method
              Set or return backgroundcolor of the TurtleScreen.

              Arguments (if given): a color string or three numbers
              in the range 0..colormode or a 3-tuple of such numbers.


              >>> screen.bgcolor("orange")
              >>> screen.bgcolor()
              "orange"
              >>> screen.bgcolor(0.5,0,0.5)
              >>> screen.bgcolor()
              "#800080"

          >>> help(Turtle.penup)
          Help on method penup in module turtle:

          penup(self) unbound turtle.Turtle method
              Pull the pen up -- no drawing when moving.

              Aliases: penup | pu | up

              No argument

              >>> turtle.penup()

   - The docstrings of the functions which are derived from methods have
     a modified form:

          >>> help(bgcolor)
          Help on function bgcolor in module turtle:

          bgcolor(*args)
              Set or return backgroundcolor of the TurtleScreen.

              Arguments (if given): a color string or three numbers
              in the range 0..colormode or a 3-tuple of such numbers.

              Example::

                >>> bgcolor("orange")
                >>> bgcolor()
                "orange"
                >>> bgcolor(0.5,0,0.5)
                >>> bgcolor()
                "#800080"

          >>> help(penup)
          Help on function penup in module turtle:

          penup()
              Pull the pen up -- no drawing when moving.

              Aliases: penup | pu | up

              No argument

              Example:
              >>> penup()

These modified docstrings are created automatically together with the
function definitions that are derived from the methods at import time.


File: python.info,  Node: Translation of docstrings into different languages,  Next: How to configure Screen and Turtles,  Prev: How to use help,  Up: Help and configuration

5.25.10.43 Translation of docstrings into different languages
.............................................................

There is a utility to create a dictionary the keys of which are the
method names and the values of which are the docstrings of the public
methods of the classes Screen and Turtle.

 -- Function: turtle.write_docstringdict
          (filename='turtle_docstringdict')


     Parameters: ‘filename’ – a string, used as filename

     Create and write docstring-dictionary to a Python script with the
     given filename.  This function has to be called explicitly (it is
     not used by the turtle graphics classes).  The docstring dictionary
     will be written to the Python script ‘`filename'.py’.  It is
     intended to serve as a template for translation of the docstrings
     into different languages.

If you (or your students) want to use ‘turtle’ with online help in your
native language, you have to translate the docstrings and save the
resulting file as e.g.  ‘turtle_docstringdict_german.py’.

If you have an appropriate entry in your ‘turtle.cfg’ file this
dictionary will be read in at import time and will replace the original
English docstrings.

At the time of this writing there are docstring dictionaries in German
and in Italian.  (Requests please to <glingl@aon.at>.)


File: python.info,  Node: How to configure Screen and Turtles,  Prev: Translation of docstrings into different languages,  Up: Help and configuration

5.25.10.44 How to configure Screen and Turtles
..............................................

The built-in default configuration mimics the appearance and behaviour
of the old turtle module in order to retain best possible compatibility
with it.

If you want to use a different configuration which better reflects the
features of this module or which better fits to your needs, e.g.  for
use in a classroom, you can prepare a configuration file ‘turtle.cfg’
which will be read at import time and modify the configuration according
to its settings.

The built in configuration would correspond to the following
‘turtle.cfg’:

     width = 0.5
     height = 0.75
     leftright = None
     topbottom = None
     canvwidth = 400
     canvheight = 300
     mode = standard
     colormode = 1.0
     delay = 10
     undobuffersize = 1000
     shape = classic
     pencolor = black
     fillcolor = black
     resizemode = noresize
     visible = True
     language = english
     exampleturtle = turtle
     examplescreen = screen
     title = Python Turtle Graphics
     using_IDLE = False

Short explanation of selected entries:

   - The first four lines correspond to the arguments of the *note
     Screen.setup: 4177. method.

   - Line 5 and 6 correspond to the arguments of the method *note
     Screen.screensize: 415f.

   - 'shape' can be any of the built-in shapes, e.g: arrow, turtle, etc.
     For more info try ‘help(shape)’.

   - If you want to use no fill color (i.e.  make the turtle
     transparent), you have to write ‘fillcolor = ""’ (but all nonempty
     strings must not have quotes in the cfg file).

   - If you want to reflect the turtle its state, you have to use
     ‘resizemode = auto’.

   - If you set e.g.  ‘language = italian’ the docstringdict
     ‘turtle_docstringdict_italian.py’ will be loaded at import time (if
     present on the import path, e.g.  in the same directory as
     ‘turtle’).

   - The entries 'exampleturtle' and 'examplescreen' define the names of
     these objects as they occur in the docstrings.  The transformation
     of method-docstrings to function-docstrings will delete these names
     from the docstrings.

   - 'using_IDLE': Set this to ‘True’ if you regularly work with IDLE
     and its ‘-n’ switch (“no subprocess”).  This will prevent *note
     exitonclick(): 4176. to enter the mainloop.

There can be a ‘turtle.cfg’ file in the directory where ‘turtle’ is
stored and an additional one in the current working directory.  The
latter will override the settings of the first one.

The ‘Lib/turtledemo’ directory contains a ‘turtle.cfg’ file.  You can
study it as an example and see its effects when running the demos
(preferably not from within the demo-viewer).


File: python.info,  Node: turtledemo — Demo scripts,  Next: Changes since Python 2 6,  Prev: Help and configuration,  Up: turtle — Turtle graphics

5.25.10.45 ‘turtledemo’ — Demo scripts
......................................

The ‘turtledemo’ package includes a set of demo scripts.  These scripts
can be run and viewed using the supplied demo viewer as follows:

     python -m turtledemo

Alternatively, you can run the demo scripts individually.  For example,

     python -m turtledemo.bytedesign

The ‘turtledemo’ package directory contains:

   - A demo viewer ‘__main__.py’ which can be used to view the
     sourcecode of the scripts and run them at the same time.

   - Multiple scripts demonstrating different features of the ‘turtle’
     module.  Examples can be accessed via the Examples menu.  They can
     also be run standalone.

   - A ‘turtle.cfg’ file which serves as an example of how to write and
     use such files.

The demo scripts are:

Name                         Description                        Features
                                                                
-----------------------------------------------------------------------------------------------------------
                                                                
‘bytedesign’                 complex classical turtle           *note tracer(): 4162,
                             graphics pattern                   *note delay(): 4161,
                                                                *note update(): 4163.
                                                                
                                                                
‘chaos’                      graphs Verhulst dynamics, shows    world coordinates
                             that computer’s computations can   
                             generate results sometimes
                             against the common sense
                             expectations
                             
                                                                
‘clock’                      analog clock showing time of       turtles as clock’s hands,
                             your computer                      *note ontimer(): 4169.
                                                                
                                                                
‘colormixer’                 experiment with r, g, b            *note ondrag(): 4150.
                                                                
                                                                
‘forest’                     3 breadth-first trees              randomization
                                                                
                                                                
‘fractalcurves’              Hilbert & Koch curves              recursion
                                                                
                                                                
‘lindenmayer’                ethnomathematics (indian kolams)   L-System
                                                                
                                                                
‘minimal_hanoi’              Towers of Hanoi                    Rectangular Turtles as Hanoi discs
                                                                (*note shape(): 4146,
                                                                *note shapesize(): 4148.)
                                                                
                                                                
‘nim’                        play the classical nim game with   turtles as nimsticks, event driven
                             three heaps of sticks against      (mouse, keyboard)
                             the computer.                      
                             
                                                                
‘paint’                      super minimalistic drawing         *note onclick(): 414e.
                             program                            
                             
                                                                
‘peace’                      elementary                         turtle: appearance and animation
                                                                
                                                                
‘penrose’                    aperiodic tiling with kites and    *note stamp(): 4120.
                             darts                              
                             
                                                                
‘planet_and_moon’            simulation of gravitational        compound shapes, *note Vec2D: 417b.
                             system                             
                             
                                                                
‘rosette’                    a pattern from the wikipedia       *note clone(): 4154, *note undo(): 4123.
                             article on turtle graphics         
                             
                                                                
‘round_dance’                dancing turtles rotating           compound shapes, *note clone(): 4154.
                             pairwise in opposite direction     *note shapesize(): 4148,
                                                                *note tilt(): 414b,
                                                                *note get_shapepoly(): 414d,
                                                                *note update(): 4163.
                                                                
                                                                
‘sorting_animate’            visual demonstration of            simple alignment, randomization
                             different sorting methods          
                             
                                                                
‘tree’                       a (graphical) breadth first tree   *note clone(): 4154.
                             (using generators)                 
                             
                                                                
‘two_canvases’               simple design                      turtles on two canvases
                                                                
                                                                
‘yinyang’                    another elementary example         *note circle(): 411e.
                                                                

Have fun!


File: python.info,  Node: Changes since Python 2 6,  Next: Changes since Python 3 0,  Prev: turtledemo — Demo scripts,  Up: turtle — Turtle graphics

5.25.10.46 Changes since Python 2.6
...................................

   - The methods *note Turtle.tracer: 4162, *note Turtle.window_width:
     4174. and *note Turtle.window_height: 4173. have been eliminated.
     Methods with these names and functionality are now available only
     as methods of *note Screen: 410b.  The functions derived from these
     remain available.  (In fact already in Python 2.6 these methods
     were merely duplications of the corresponding *note TurtleScreen:
     4188./‘Screen’ methods.)

   - The method ‘Turtle.fill()’ has been eliminated.  The behaviour of
     *note begin_fill(): 413c. and *note end_fill(): 413d. have changed
     slightly: now every filling process must be completed with an
     ‘end_fill()’ call.

   - A method *note Turtle.filling: 413b. has been added.  It returns a
     boolean value: ‘True’ if a filling process is under way, ‘False’
     otherwise.  This behaviour corresponds to a ‘fill()’ call without
     arguments in Python 2.6.


File: python.info,  Node: Changes since Python 3 0,  Prev: Changes since Python 2 6,  Up: turtle — Turtle graphics

5.25.10.47 Changes since Python 3.0
...................................

   - The *note Turtle: 4199. methods *note shearfactor(): 414a, *note
     shapetransform(): 414c. and *note get_shapepoly(): 414d. have been
     added.  Thus the full range of regular linear transforms is now
     available for transforming turtle shapes.  *note tiltangle(): 728.
     has been enhanced in functionality: it now can be used to get or
     set the tilt angle.

   - The *note Screen: 410b. method *note onkeypress(): 4167. has been
     added as a complement to *note onkey(): 4165.  As the latter binds
     actions to the key release event, an alias: *note onkeyrelease():
     4166. was also added for it.

   - The method *note Screen.mainloop: 416a. has been added, so there is
     no longer a need to use the standalone ‘mainloop()’ function when
     working with *note Screen: 410b. and *note Turtle: 4199. objects.

   - Two input methods have been added: *note Screen.textinput: 1a21.
     and *note Screen.numinput: 1a22.  These pop up input dialogs and
     return strings and numbers respectively.

   - Two example scripts ‘tdemo_nim.py’ and ‘tdemo_round_dance.py’ have
     been added to the ‘Lib/turtledemo’ directory.


File: python.info,  Node: Development Tools,  Next: Debugging and Profiling,  Prev: Graphical user interfaces with Tk,  Up: The Python Standard Library

5.26 Development Tools
======================

The modules described in this chapter help you write software.  For
example, the *note pydoc: b5. module takes a module and generates
documentation based on the module’s contents.  The *note doctest: 3a.
and *note unittest: 106. modules contains frameworks for writing unit
tests that automatically exercise code and verify that the expected
output is produced.

The list of modules described in this chapter is:

* Menu:

* typing — Support for type hints::
* pydoc — Documentation generator and online help system::
* Python Development Mode::
* doctest — Test interactive Python examples::
* unittest — Unit testing framework::
* unittest.mock — mock object library: unittest mock — mock object library.
* unittest.mock — getting started: unittest mock — getting started.
* test — Regression tests package for Python::
* test.support — Utilities for the Python test suite: test support — Utilities for the Python test suite.
* test.support.socket_helper — Utilities for socket tests: test support socket_helper — Utilities for socket tests.
* test.support.script_helper — Utilities for the Python execution tests: test support script_helper — Utilities for the Python execution tests.
* test.support.bytecode_helper — Support tools for testing correct bytecode generation: test support bytecode_helper — Support tools for testing correct bytecode generation.
* test.support.threading_helper — Utilities for threading tests: test support threading_helper — Utilities for threading tests.
* test.support.os_helper — Utilities for os tests: test support os_helper — Utilities for os tests.
* test.support.import_helper — Utilities for import tests: test support import_helper — Utilities for import tests.
* test.support.warnings_helper — Utilities for warnings tests: test support warnings_helper — Utilities for warnings tests.


File: python.info,  Node: typing — Support for type hints,  Next: pydoc — Documentation generator and online help system,  Up: Development Tools

5.26.1 ‘typing’ — Support for type hints
----------------------------------------

Added in version 3.5.

'Source code:' Lib/typing.py(1)

     Note: The Python runtime does not enforce function and variable
     type annotations.  They can be used by third party tools such as
     *note type checkers: 26d, IDEs, linters, etc.

__________________________________________________________________

This module provides runtime support for type hints.

Consider the function below:

     def surface_area_of_cube(edge_length: float) -> str:
         return f"The surface area of the cube is {6 * edge_length ** 2}."

The function ‘surface_area_of_cube’ takes an argument expected to be an
instance of *note float: 2f7, as indicated by the *note type hint: 2131.
‘edge_length: float’.  The function is expected to return an instance of
*note str: 44f, as indicated by the ‘-> str’ hint.

While type hints can be simple classes like *note float: 2f7. or *note
str: 44f, they can also be more complex.  The *note typing: 104. module
provides a vocabulary of more advanced type hints.

New features are frequently added to the ‘typing’ module.  The
typing_extensions(2) package provides backports of these new features to
older versions of Python.

See also
........

Typing cheat sheet(3)

     A quick overview of type hints (hosted at the mypy docs)

Type System Reference section of the mypy docs(4)

     The Python typing system is standardised via PEPs, so this
     reference should broadly apply to most Python type checkers.  (Some
     parts may still be specific to mypy.)

Static Typing with Python(5)

     Type-checker-agnostic documentation written by the community
     detailing type system features, useful typing related tools and
     typing best practices.

* Menu:

* Specification for the Python Type System::
* Type aliases::
* NewType::
* Annotating callable objects::
* Generics::
* Annotating tuples::
* The type of class objects::
* Annotating generators and coroutines::
* User-defined generic types::
* The Any type::
* Nominal vs structural subtyping::
* Module contents: Module contents<4>.
* Deprecation Timeline of Major Features::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/typing.py

   (2) https://pypi.org/project/typing_extensions/

   (3) https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html

   (4) https://mypy.readthedocs.io/en/stable/index.html

   (5) https://typing.python.org/en/latest/


File: python.info,  Node: Specification for the Python Type System,  Next: Type aliases,  Up: typing — Support for type hints

5.26.1.1 Specification for the Python Type System
.................................................

The canonical, up-to-date specification of the Python type system can be
found at Specification for the Python type system(1).

   ---------- Footnotes ----------

   (1) https://typing.python.org/en/latest/spec/index.html


File: python.info,  Node: Type aliases,  Next: NewType,  Prev: Specification for the Python Type System,  Up: typing — Support for type hints

5.26.1.2 Type aliases
.....................

A type alias is defined using the *note type: 43b. statement, which
creates an instance of *note TypeAliasType: 458.  In this example,
‘Vector’ and ‘list[float]’ will be treated equivalently by static type
checkers:

     type Vector = list[float]

     def scale(scalar: float, vector: Vector) -> Vector:
         return [scalar * num for num in vector]

     # passes type checking; a list of floats qualifies as a Vector.
     new_vector = scale(2.0, [1.0, -4.2, 5.4])

Type aliases are useful for simplifying complex type signatures.  For
example:

     from collections.abc import Sequence

     type ConnectionOptions = dict[str, str]
     type Address = tuple[str, int]
     type Server = tuple[Address, ConnectionOptions]

     def broadcast_message(message: str, servers: Sequence[Server]) -> None:
         ...

     # The static type checker will treat the previous type signature as
     # being exactly equivalent to this one.
     def broadcast_message(
         message: str,
         servers: Sequence[tuple[tuple[str, int], dict[str, str]]]
     ) -> None:
         ...

The *note type: 43b. statement is new in Python 3.12.  For backwards
compatibility, type aliases can also be created through simple
assignment:

     Vector = list[float]

Or marked with *note TypeAlias: 7cd. to make it explicit that this is a
type alias, not a normal variable assignment:

     from typing import TypeAlias

     Vector: TypeAlias = list[float]


File: python.info,  Node: NewType,  Next: Annotating callable objects,  Prev: Type aliases,  Up: typing — Support for type hints

5.26.1.3 NewType
................

Use the *note NewType: d1c. helper to create distinct types:

     from typing import NewType

     UserId = NewType('UserId', int)
     some_id = UserId(524313)

The static type checker will treat the new type as if it were a subclass
of the original type.  This is useful in helping catch logical errors:

     def get_user_name(user_id: UserId) -> str:
         ...

     # passes type checking
     user_a = get_user_name(UserId(42351))

     # fails type checking; an int is not a UserId
     user_b = get_user_name(-1)

You may still perform all ‘int’ operations on a variable of type
‘UserId’, but the result will always be of type ‘int’.  This lets you
pass in a ‘UserId’ wherever an ‘int’ might be expected, but will prevent
you from accidentally creating a ‘UserId’ in an invalid way:

     # 'output' is of type 'int', not 'UserId'
     output = UserId(23413) + UserId(54341)

Note that these checks are enforced only by the static type checker.  At
runtime, the statement ‘Derived = NewType('Derived', Base)’ will make
‘Derived’ a callable that immediately returns whatever parameter you
pass it.  That means the expression ‘Derived(some_value)’ does not
create a new class or introduce much overhead beyond that of a regular
function call.

More precisely, the expression ‘some_value is Derived(some_value)’ is
always true at runtime.

It is invalid to create a subtype of ‘Derived’:

     from typing import NewType

     UserId = NewType('UserId', int)

     # Fails at runtime and does not pass type checking
     class AdminUserId(UserId): pass

However, it is possible to create a *note NewType: d1c. based on a
‘derived’ ‘NewType’:

     from typing import NewType

     UserId = NewType('UserId', int)

     ProUserId = NewType('ProUserId', UserId)

and typechecking for ‘ProUserId’ will work as expected.

See PEP 484(1) for more details.

     Note: Recall that the use of a type alias declares two types to be
     'equivalent' to one another.  Doing ‘type Alias = Original’ will
     make the static type checker treat ‘Alias’ as being 'exactly
     equivalent' to ‘Original’ in all cases.  This is useful when you
     want to simplify complex type signatures.

     In contrast, ‘NewType’ declares one type to be a 'subtype' of
     another.  Doing ‘Derived = NewType('Derived', Original)’ will make
     the static type checker treat ‘Derived’ as a 'subclass' of
     ‘Original’, which means a value of type ‘Original’ cannot be used
     in places where a value of type ‘Derived’ is expected.  This is
     useful when you want to prevent logic errors with minimal runtime
     cost.

Added in version 3.5.2.

Changed in version 3.10: ‘NewType’ is now a class rather than a
function.  As a result, there is some additional runtime cost when
calling ‘NewType’ over a regular function.

Changed in version 3.11: The performance of calling ‘NewType’ has been
restored to its level in Python 3.9.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: Annotating callable objects,  Next: Generics,  Prev: NewType,  Up: typing — Support for type hints

5.26.1.4 Annotating callable objects
....................................

Functions – or other *note callable: 2acb. objects – can be annotated
using *note collections.abc.Callable: 7ef. or deprecated *note
typing.Callable: 7c9.  ‘Callable[[int], str]’ signifies a function that
takes a single parameter of type *note int: 257. and returns a *note
str: 44f.

For example:

     from collections.abc import Callable, Awaitable

     def feeder(get_next_item: Callable[[], str]) -> None:
         ...  # Body

     def async_query(on_success: Callable[[int], None],
                     on_error: Callable[[int, Exception], None]) -> None:
         ...  # Body

     async def on_update(value: str) -> None:
         ...  # Body

     callback: Callable[[str], Awaitable[None]] = on_update

The subscription syntax must always be used with exactly two values: the
argument list and the return type.  The argument list must be a list of
types, a *note ParamSpec: 15e, *note Concatenate: 7c8, or an ellipsis
(‘...’).  The return type must be a single type.

If a literal ellipsis ‘...’ is given as the argument list, it indicates
that a callable with any arbitrary parameter list would be acceptable:

     def concat(x: str, y: str) -> str:
         return x + y

     x: Callable[..., str]
     x = str     # OK
     x = concat  # Also OK

‘Callable’ cannot express complex signatures such as functions that take
a variadic number of arguments, *note overloaded functions: 41af, or
functions that have keyword-only parameters.  However, these signatures
can be expressed by defining a *note Protocol: 264. class with a *note
__call__(): 55b. method:

     from collections.abc import Iterable
     from typing import Protocol

     class Combiner(Protocol):
         def __call__(self, *vals: bytes, maxlen: int | None = None) -> list[bytes]: ...

     def batch_proc(data: Iterable[bytes], cb_results: Combiner) -> bytes:
         for item in data:
             ...

     def good_cb(*vals: bytes, maxlen: int | None = None) -> list[bytes]:
         ...
     def bad_cb(*vals: bytes, maxitems: int | None) -> list[bytes]:
         ...

     batch_proc([], good_cb)  # OK
     batch_proc([], bad_cb)   # Error! Argument 2 has incompatible type because of
                              # different name and kind in the callback

Callables which take other callables as arguments may indicate that
their parameter types are dependent on each other using *note ParamSpec:
15e.  Additionally, if that callable adds or removes arguments from
other callables, the *note Concatenate: 7c8. operator may be used.  They
take the form ‘Callable[ParamSpecVariable, ReturnType]’ and
‘Callable[Concatenate[Arg1Type, Arg2Type, ..., ParamSpecVariable],
ReturnType]’ respectively.

Changed in version 3.10: ‘Callable’ now supports *note ParamSpec: 15e.
and *note Concatenate: 7c8.  See PEP 612(1) for more details.

See also
........

The documentation for *note ParamSpec: 15e. and *note Concatenate: 7c8.
provides examples of usage in ‘Callable’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0612/


File: python.info,  Node: Generics,  Next: Annotating tuples,  Prev: Annotating callable objects,  Up: typing — Support for type hints

5.26.1.5 Generics
.................

Since type information about objects kept in containers cannot be
statically inferred in a generic way, many container classes in the
standard library support subscription to denote the expected types of
container elements.

     from collections.abc import Mapping, Sequence

     class Employee: ...

     # Sequence[Employee] indicates that all elements in the sequence
     # must be instances of "Employee".
     # Mapping[str, str] indicates that all keys and all values in the mapping
     # must be strings.
     def notify_by_email(employees: Sequence[Employee],
                         overrides: Mapping[str, str]) -> None: ...

Generic functions and classes can be parameterized by using *note type
parameter syntax: 2b3.:

     from collections.abc import Sequence

     def first[T](l: Sequence[T]) -> T:  # Function is generic over the TypeVar "T"
         return l[0]

Or by using the *note TypeVar: 15d. factory directly:

     from collections.abc import Sequence
     from typing import TypeVar

     U = TypeVar('U')                  # Declare type variable "U"

     def second(l: Sequence[U]) -> U:  # Function is generic over the TypeVar "U"
         return l[1]

Changed in version 3.12: Syntactic support for generics is new in Python
3.12.


File: python.info,  Node: Annotating tuples,  Next: The type of class objects,  Prev: Generics,  Up: typing — Support for type hints

5.26.1.6 Annotating tuples
..........................

For most containers in Python, the typing system assumes that all
elements in the container will be of the same type.  For example:

     from collections.abc import Mapping

     # Type checker will infer that all elements in ``x`` are meant to be ints
     x: list[int] = []

     # Type checker error: ``list`` only accepts a single type argument:
     y: list[int, str] = [1, 'foo']

     # Type checker will infer that all keys in ``z`` are meant to be strings,
     # and that all values in ``z`` are meant to be either strings or ints
     z: Mapping[str, str | int] = {}

*note list: 614. only accepts one type argument, so a type checker would
emit an error on the ‘y’ assignment above.  Similarly, *note Mapping:
8d3. only accepts two type arguments: the first indicates the type of
the keys, and the second indicates the type of the values.

Unlike most other Python containers, however, it is common in idiomatic
Python code for tuples to have elements which are not all of the same
type.  For this reason, tuples are special-cased in Python’s typing
system.  *note tuple: 373. accepts 'any number' of type arguments:

     # OK: ``x`` is assigned to a tuple of length 1 where the sole element is an int
     x: tuple[int] = (5,)

     # OK: ``y`` is assigned to a tuple of length 2;
     # element 1 is an int, element 2 is a str
     y: tuple[int, str] = (5, "foo")

     # Error: the type annotation indicates a tuple of length 1,
     # but ``z`` has been assigned to a tuple of length 3
     z: tuple[int] = (1, 2, 3)

To denote a tuple which could be of 'any' length, and in which all
elements are of the same type ‘T’, use the literal ellipsis ‘...’:
‘tuple[T, ...]’.  To denote an empty tuple, use ‘tuple[()]’.  Using
plain ‘tuple’ as an annotation is equivalent to using ‘tuple[Any, ...]’:

     x: tuple[int, ...] = (1, 2)
     # These reassignments are OK: ``tuple[int, ...]`` indicates x can be of any length
     x = (1, 2, 3)
     x = ()
     # This reassignment is an error: all elements in ``x`` must be ints
     x = ("foo", "bar")

     # ``y`` can only ever be assigned to an empty tuple
     y: tuple[()] = ()

     z: tuple = ("foo", "bar")
     # These reassignments are OK: plain ``tuple`` is equivalent to ``tuple[Any, ...]``
     z = (1, 2, 3)
     z = ()


File: python.info,  Node: The type of class objects,  Next: Annotating generators and coroutines,  Prev: Annotating tuples,  Up: typing — Support for type hints

5.26.1.7 The type of class objects
..................................

A variable annotated with ‘C’ may accept a value of type ‘C’.  In
contrast, a variable annotated with ‘type[C]’ (or deprecated *note
typing.Type[C]: 41b4.) may accept values that are classes themselves –
specifically, it will accept the 'class object' of ‘C’.  For example:

     a = 3         # Has type ``int``
     b = int       # Has type ``type[int]``
     c = type(a)   # Also has type ``type[int]``

Note that ‘type[C]’ is covariant:

     class User: ...
     class ProUser(User): ...
     class TeamUser(User): ...

     def make_new_user(user_class: type[User]) -> User:
         # ...
         return user_class()

     make_new_user(User)      # OK
     make_new_user(ProUser)   # Also OK: ``type[ProUser]`` is a subtype of ``type[User]``
     make_new_user(TeamUser)  # Still fine
     make_new_user(User())    # Error: expected ``type[User]`` but got ``User``
     make_new_user(int)       # Error: ``type[int]`` is not a subtype of ``type[User]``

The only legal parameters for *note type: d71. are classes, *note Any:
6af, *note type variables: 212f, and unions of any of these types.  For
example:

     def new_non_team_user(user_class: type[BasicUser | ProUser]): ...

     new_non_team_user(BasicUser)  # OK
     new_non_team_user(ProUser)    # OK
     new_non_team_user(TeamUser)   # Error: ``type[TeamUser]`` is not a subtype
                                   # of ``type[BasicUser | ProUser]``
     new_non_team_user(User)       # Also an error

‘type[Any]’ is equivalent to *note type: d71, which is the root of
Python’s *note metaclass hierarchy: 2124.


File: python.info,  Node: Annotating generators and coroutines,  Next: User-defined generic types,  Prev: The type of class objects,  Up: typing — Support for type hints

5.26.1.8 Annotating generators and coroutines
.............................................

A generator can be annotated using the generic type *note
Generator[YieldType, SendType, ReturnType]: e0b.  For example:

     def echo_round() -> Generator[int, float, str]:
         sent = yield 0
         while sent >= 0:
             sent = yield round(sent)
         return 'Done'

Note that unlike many other generic classes in the standard library, the
‘SendType’ of *note Generator: e0b. behaves contravariantly, not
covariantly or invariantly.

The ‘SendType’ and ‘ReturnType’ parameters default to ‘None’:

     def infinite_stream(start: int) -> Generator[int]:
         while True:
             yield start
             start += 1

It is also possible to set these types explicitly:

     def infinite_stream(start: int) -> Generator[int, None, None]:
         while True:
             yield start
             start += 1

Simple generators that only ever yield values can also be annotated as
having a return type of either *note Iterable[YieldType]: 2405. or *note
Iterator[YieldType]: 2406.:

     def infinite_stream(start: int) -> Iterator[int]:
         while True:
             yield start
             start += 1

Async generators are handled in a similar fashion, but don’t expect a
‘ReturnType’ type argument (*note AsyncGenerator[YieldType, SendType]:
cae.).  The ‘SendType’ argument defaults to ‘None’, so the following
definitions are equivalent:

     async def infinite_stream(start: int) -> AsyncGenerator[int]:
         while True:
             yield start
             start = await increment(start)

     async def infinite_stream(start: int) -> AsyncGenerator[int, None]:
         while True:
             yield start
             start = await increment(start)

As in the synchronous case, *note AsyncIterable[YieldType]: e0f. and
*note AsyncIterator[YieldType]: e0e. are available as well:

     async def infinite_stream(start: int) -> AsyncIterator[int]:
         while True:
             yield start
             start = await increment(start)

Coroutines can be annotated using *note Coroutine[YieldType, SendType,
ReturnType]: e0d.  Generic arguments correspond to those of *note
Generator: e0b, for example:

     from collections.abc import Coroutine
     c: Coroutine[list[str], str, int]  # Some coroutine defined elsewhere
     x = c.send('hi')                   # Inferred type of 'x' is list[str]
     async def bar() -> None:
         y = await c                    # Inferred type of 'y' is int


File: python.info,  Node: User-defined generic types,  Next: The Any type,  Prev: Annotating generators and coroutines,  Up: typing — Support for type hints

5.26.1.9 User-defined generic types
...................................

A user-defined class can be defined as a generic class.

     from logging import Logger

     class LoggedVar[T]:
         def __init__(self, value: T, name: str, logger: Logger) -> None:
             self.name = name
             self.logger = logger
             self.value = value

         def set(self, new: T) -> None:
             self.log('Set ' + repr(self.value))
             self.value = new

         def get(self) -> T:
             self.log('Get ' + repr(self.value))
             return self.value

         def log(self, message: str) -> None:
             self.logger.info('%s: %s', self.name, message)

This syntax indicates that the class ‘LoggedVar’ is parameterised around
a single *note type variable: 41b7. ‘T’ .  This also makes ‘T’ valid as
a type within the class body.

Generic classes implicitly inherit from *note Generic: 15fb.  For
compatibility with Python 3.11 and lower, it is also possible to inherit
explicitly from ‘Generic’ to indicate a generic class:

     from typing import TypeVar, Generic

     T = TypeVar('T')

     class LoggedVar(Generic[T]):
         ...

Generic classes have *note __class_getitem__(): 73e. methods, meaning
they can be parameterised at runtime (e.g.  ‘LoggedVar[int]’ below):

     from collections.abc import Iterable

     def zero_all_vars(vars: Iterable[LoggedVar[int]]) -> None:
         for var in vars:
             var.set(0)

A generic type can have any number of type variables.  All varieties of
*note TypeVar: 15d. are permissible as parameters for a generic type:

     from typing import TypeVar, Generic, Sequence

     class WeirdTrio[T, B: Sequence[bytes], S: (int, str)]:
         ...

     OldT = TypeVar('OldT', contravariant=True)
     OldB = TypeVar('OldB', bound=Sequence[bytes], covariant=True)
     OldS = TypeVar('OldS', int, str)

     class OldWeirdTrio(Generic[OldT, OldB, OldS]):
         ...

Each type variable argument to *note Generic: 15fb. must be distinct.
This is thus invalid:

     from typing import TypeVar, Generic
     ...

     class Pair[M, M]:  # SyntaxError
         ...

     T = TypeVar('T')

     class Pair(Generic[T, T]):   # INVALID
         ...

Generic classes can also inherit from other classes:

     from collections.abc import Sized

     class LinkedList[T](Sized):
         ...

When inheriting from generic classes, some type parameters could be
fixed:

     from collections.abc import Mapping

     class MyDict[T](Mapping[str, T]):
         ...

In this case ‘MyDict’ has a single parameter, ‘T’.

Using a generic class without specifying type parameters assumes *note
Any: 6af. for each position.  In the following example, ‘MyIterable’ is
not generic but implicitly inherits from ‘Iterable[Any]’:

     from collections.abc import Iterable

     class MyIterable(Iterable): # Same as Iterable[Any]
         ...

User-defined generic type aliases are also supported.  Examples:

     from collections.abc import Iterable

     type Response[S] = Iterable[S] | int

     # Return type here is same as Iterable[str] | int
     def response(query: str) -> Response[str]:
         ...

     type Vec[T] = Iterable[tuple[T, T]]

     def inproduct[T: (int, float, complex)](v: Vec[T]) -> T: # Same as Iterable[tuple[T, T]]
         return sum(x*y for x, y in v)

For backward compatibility, generic type aliases can also be created
through a simple assignment:

     from collections.abc import Iterable
     from typing import TypeVar

     S = TypeVar("S")
     Response = Iterable[S] | int

Changed in version 3.7: *note Generic: 15fb. no longer has a custom
metaclass.

Changed in version 3.12: Syntactic support for generics and type aliases
is new in version 3.12.  Previously, generic classes had to explicitly
inherit from *note Generic: 15fb. or contain a type variable in one of
their bases.

User-defined generics for parameter expressions are also supported via
parameter specification variables in the form ‘[**P]’.  The behavior is
consistent with type variables’ described above as parameter
specification variables are treated by the ‘typing’ module as a
specialized type variable.  The one exception to this is that a list of
types can be used to substitute a *note ParamSpec: 15e.:

     >>> class Z[T, **P]: ...  # T is a TypeVar; P is a ParamSpec
     ...
     >>> Z[int, [dict, float]]
     __main__.Z[int, [dict, float]]

Classes generic over a *note ParamSpec: 15e. can also be created using
explicit inheritance from *note Generic: 15fb.  In this case, ‘**’ is
not used:

     from typing import ParamSpec, Generic

     P = ParamSpec('P')

     class Z(Generic[P]):
         ...

Another difference between *note TypeVar: 15d. and *note ParamSpec: 15e.
is that a generic with only one parameter specification variable will
accept parameter lists in the forms ‘X[[Type1, Type2, ...]]’ and also
‘X[Type1, Type2, ...]’ for aesthetic reasons.  Internally, the latter is
converted to the former, so the following are equivalent:

     >>> class X[**P]: ...
     ...
     >>> X[int, str]
     __main__.X[[int, str]]
     >>> X[[int, str]]
     __main__.X[[int, str]]

Note that generics with *note ParamSpec: 15e. may not have correct
‘__parameters__’ after substitution in some cases because they are
intended primarily for static type checking.

Changed in version 3.10: *note Generic: 15fb. can now be parameterized
over parameter expressions.  See *note ParamSpec: 15e. and PEP 612(1)
for more details.

A user-defined generic class can have ABCs as base classes without a
metaclass conflict.  Generic metaclasses are not supported.  The outcome
of parameterizing generics is cached, and most types in the ‘typing’
module are *note hashable: 613. and comparable for equality.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0612/


File: python.info,  Node: The Any type,  Next: Nominal vs structural subtyping,  Prev: User-defined generic types,  Up: typing — Support for type hints

5.26.1.10 The ‘Any’ type
........................

A special kind of type is *note Any: 6af.  A static type checker will
treat every type as being compatible with ‘Any’ and ‘Any’ as being
compatible with every type.

This means that it is possible to perform any operation or method call
on a value of type *note Any: 6af. and assign it to any variable:

     from typing import Any

     a: Any = None
     a = []          # OK
     a = 2           # OK

     s: str = ''
     s = a           # OK

     def foo(item: Any) -> int:
         # Passes type checking; 'item' could be any type,
         # and that type might have a 'bar' method
         item.bar()
         ...

Notice that no type checking is performed when assigning a value of type
*note Any: 6af. to a more precise type.  For example, the static type
checker did not report an error when assigning ‘a’ to ‘s’ even though
‘s’ was declared to be of type *note str: 44f. and receives an *note
int: 257. value at runtime!

Furthermore, all functions without a return type or parameter types will
implicitly default to using *note Any: 6af.:

     def legacy_parser(text):
         ...
         return data

     # A static type checker will treat the above
     # as having the same signature as:
     def legacy_parser(text: Any) -> Any:
         ...
         return data

This behavior allows *note Any: 6af. to be used as an 'escape hatch'
when you need to mix dynamically and statically typed code.

Contrast the behavior of *note Any: 6af. with the behavior of *note
object: a9b.  Similar to ‘Any’, every type is a subtype of ‘object’.
However, unlike ‘Any’, the reverse is not true: ‘object’ is 'not' a
subtype of every other type.

That means when the type of a value is *note object: a9b, a type checker
will reject almost all operations on it, and assigning it to a variable
(or using it as a return value) of a more specialized type is a type
error.  For example:

     def hash_a(item: object) -> int:
         # Fails type checking; an object does not have a 'magic' method.
         item.magic()
         ...

     def hash_b(item: Any) -> int:
         # Passes type checking
         item.magic()
         ...

     # Passes type checking, since ints and strs are subclasses of object
     hash_a(42)
     hash_a("foo")

     # Passes type checking, since Any is compatible with all types
     hash_b(42)
     hash_b("foo")

Use *note object: a9b. to indicate that a value could be any type in a
typesafe manner.  Use *note Any: 6af. to indicate that a value is
dynamically typed.


File: python.info,  Node: Nominal vs structural subtyping,  Next: Module contents<4>,  Prev: The Any type,  Up: typing — Support for type hints

5.26.1.11 Nominal vs structural subtyping
.........................................

Initially PEP 484(1) defined the Python static type system as using
'nominal subtyping'.  This means that a class ‘A’ is allowed where a
class ‘B’ is expected if and only if ‘A’ is a subclass of ‘B’.

This requirement previously also applied to abstract base classes, such
as *note Iterable: 2405.  The problem with this approach is that a class
had to be explicitly marked to support them, which is unpythonic and
unlike what one would normally do in idiomatic dynamically typed Python
code.  For example, this conforms to PEP 484(2):

     from collections.abc import Sized, Iterable, Iterator

     class Bucket(Sized, Iterable[int]):
         ...
         def __len__(self) -> int: ...
         def __iter__(self) -> Iterator[int]: ...

PEP 544(3) solves this problem by allowing users to write the above code
without explicit base classes in the class definition, allowing ‘Bucket’
to be implicitly considered a subtype of both ‘Sized’ and
‘Iterable[int]’ by static type checkers.  This is known as 'structural
subtyping' (or static duck-typing):

     from collections.abc import Iterator, Iterable

     class Bucket:  # Note: no base classes
         ...
         def __len__(self) -> int: ...
         def __iter__(self) -> Iterator[int]: ...

     def collect(items: Iterable[int]) -> int: ...
     result = collect(Bucket())  # Passes type check

Moreover, by subclassing a special class *note Protocol: 264, a user can
define new custom protocols to fully enjoy structural subtyping (see
examples below).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0484/

   (3) https://peps.python.org/pep-0544/


File: python.info,  Node: Module contents<4>,  Next: Deprecation Timeline of Major Features,  Prev: Nominal vs structural subtyping,  Up: typing — Support for type hints

5.26.1.12 Module contents
.........................

The ‘typing’ module defines the following classes, functions and
decorators.

* Menu:

* Special typing primitives::
* Protocols: Protocols<3>.
* ABCs for working with IO::
* Functions and decorators::
* Introspection helpers::
* Constant::
* Deprecated aliases::


File: python.info,  Node: Special typing primitives,  Next: Protocols<3>,  Up: Module contents<4>

5.26.1.13 Special typing primitives
...................................

* Menu:

* Special types::
* Special forms::
* Building generic types and type aliases::
* Other special directives::


File: python.info,  Node: Special types,  Next: Special forms,  Up: Special typing primitives

5.26.1.14 Special types
.......................

These can be used as types in annotations.  They do not support
subscription using ‘[]’.

 -- Data: typing.Any

     Special type indicating an unconstrained type.

        * Every type is compatible with ‘Any’.

        * ‘Any’ is compatible with every type.

     Changed in version 3.11: ‘Any’ can now be used as a base class.
     This can be useful for avoiding type checker errors with classes
     that can duck type anywhere or are highly dynamic.

 -- Data: typing.AnyStr

     A *note constrained type variable: 41bd.

     Definition:

          AnyStr = TypeVar('AnyStr', str, bytes)

     ‘AnyStr’ is meant to be used for functions that may accept *note
     str: 44f. or *note bytes: 1c2. arguments but cannot allow the two
     to mix.

     For example:

          def concat(a: AnyStr, b: AnyStr) -> AnyStr:
              return a + b

          concat("foo", "bar")    # OK, output has type 'str'
          concat(b"foo", b"bar")  # OK, output has type 'bytes'
          concat("foo", b"bar")   # Error, cannot mix str and bytes

     Note that, despite its name, ‘AnyStr’ has nothing to do with the
     *note Any: 6af. type, nor does it mean “any string”.  In
     particular, ‘AnyStr’ and ‘str | bytes’ are different from each
     other and have different use cases:

          # Invalid use of AnyStr:
          # The type variable is used only once in the function signature,
          # so cannot be "solved" by the type checker
          def greet_bad(cond: bool) -> AnyStr:
              return "hi there!" if cond else b"greetings!"

          # The better way of annotating this function:
          def greet_proper(cond: bool) -> str | bytes:
              return "hi there!" if cond else b"greetings!"

     Deprecated since version 3.13, will be removed in version 3.18:
     Deprecated in favor of the new *note type parameter syntax: 2b3.
     Use ‘class A[T: (str, bytes)]: ...’ instead of importing ‘AnyStr’.
     See PEP 695(1) for more details.

     In Python 3.16, ‘AnyStr’ will be removed from ‘typing.__all__’, and
     deprecation warnings will be emitted at runtime when it is accessed
     or imported from ‘typing’.  ‘AnyStr’ will be removed from ‘typing’
     in Python 3.18.

 -- Data: typing.LiteralString

     Special type that includes only literal strings.

     Any string literal is compatible with ‘LiteralString’, as is
     another ‘LiteralString’.  However, an object typed as just ‘str’ is
     not.  A string created by composing ‘LiteralString’-typed objects
     is also acceptable as a ‘LiteralString’.

     Example:

          def run_query(sql: LiteralString) -> None:
              ...

          def caller(arbitrary_string: str, literal_string: LiteralString) -> None:
              run_query("SELECT * FROM students")  # OK
              run_query(literal_string)  # OK
              run_query("SELECT * FROM " + literal_string)  # OK
              run_query(arbitrary_string)  # type checker error
              run_query(  # type checker error
                  f"SELECT * FROM students WHERE name = {arbitrary_string}"
              )

     ‘LiteralString’ is useful for sensitive APIs where arbitrary
     user-generated strings could generate problems.  For example, the
     two cases above that generate type checker errors could be
     vulnerable to an SQL injection attack.

     See PEP 675(2) for more details.

     Added in version 3.11.

 -- Data: typing.Never
 -- Data: typing.NoReturn

     ‘Never’ and ‘NoReturn’ represent the bottom type(3), a type that
     has no members.

     They can be used to indicate that a function never returns, such as
     *note sys.exit(): 1394.:

          from typing import Never  # or NoReturn

          def stop() -> Never:
              raise RuntimeError('no way')

     Or to define a function that should never be called, as there are
     no valid arguments, such as *note assert_never(): 6aa.:

          from typing import Never  # or NoReturn

          def never_call_me(arg: Never) -> None:
              pass

          def int_or_str(arg: int | str) -> None:
              never_call_me(arg)  # type checker error
              match arg:
                  case int():
                      print("It's an int")
                  case str():
                      print("It's a str")
                  case _:
                      never_call_me(arg)  # OK, arg is of type Never (or NoReturn)

     ‘Never’ and ‘NoReturn’ have the same meaning in the type system and
     static type checkers treat both equivalently.

     Added in version 3.6.2: Added ‘NoReturn’.

     Added in version 3.11: Added ‘Never’.

 -- Data: typing.Self

     Special type to represent the current enclosed class.

     For example:

          from typing import Self, reveal_type

          class Foo:
              def return_self(self) -> Self:
                  ...
                  return self

          class SubclassOfFoo(Foo): pass

          reveal_type(Foo().return_self())  # Revealed type is "Foo"
          reveal_type(SubclassOfFoo().return_self())  # Revealed type is "SubclassOfFoo"

     This annotation is semantically equivalent to the following, albeit
     in a more succinct fashion:

          from typing import TypeVar

          Self = TypeVar("Self", bound="Foo")

          class Foo:
              def return_self(self: Self) -> Self:
                  ...
                  return self

     In general, if something returns ‘self’, as in the above examples,
     you should use ‘Self’ as the return annotation.  If
     ‘Foo.return_self’ was annotated as returning ‘"Foo"’, then the type
     checker would infer the object returned from
     ‘SubclassOfFoo.return_self’ as being of type ‘Foo’ rather than
     ‘SubclassOfFoo’.

     Other common use cases include:

        - *note classmethod: 166.s that are used as alternative
          constructors and return instances of the ‘cls’ parameter.

        - Annotating an *note __enter__(): 5cb. method which returns
          self.

     You should not use ‘Self’ as the return annotation if the method is
     not guaranteed to return an instance of a subclass when the class
     is subclassed:

          class Eggs:
              # Self would be an incorrect return annotation here,
              # as the object returned is always an instance of Eggs,
              # even in subclasses
              def returns_eggs(self) -> "Eggs":
                  return Eggs()

     See PEP 673(4) for more details.

     Added in version 3.11.

 -- Data: typing.TypeAlias

     Special annotation for explicitly declaring a *note type alias:
     457.

     For example:

          from typing import TypeAlias

          Factors: TypeAlias = list[int]

     ‘TypeAlias’ is particularly useful on older Python versions for
     annotating aliases that make use of forward references, as it can
     be hard for type checkers to distinguish these from normal variable
     assignments:

          from typing import Generic, TypeAlias, TypeVar

          T = TypeVar("T")

          # "Box" does not exist yet,
          # so we have to use quotes for the forward reference on Python <3.12.
          # Using ``TypeAlias`` tells the type checker that this is a type alias declaration,
          # not a variable assignment to a string.
          BoxOfStrings: TypeAlias = "Box[str]"

          class Box(Generic[T]):
              @classmethod
              def make_box_of_strings(cls) -> BoxOfStrings: ...

     See PEP 613(5) for more details.

     Added in version 3.10.

     Deprecated since version 3.12: ‘TypeAlias’ is deprecated in favor
     of the *note type: 43b. statement, which creates instances of *note
     TypeAliasType: 458. and which natively supports forward references.
     Note that while ‘TypeAlias’ and ‘TypeAliasType’ serve similar
     purposes and have similar names, they are distinct and the latter
     is not the type of the former.  Removal of ‘TypeAlias’ is not
     currently planned, but users are encouraged to migrate to ‘type’
     statements.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0695/

   (2) https://peps.python.org/pep-0675/

   (3) https://en.wikipedia.org/wiki/Bottom_type

   (4) https://peps.python.org/pep-0673/

   (5) https://peps.python.org/pep-0613/


File: python.info,  Node: Special forms,  Next: Building generic types and type aliases,  Prev: Special types,  Up: Special typing primitives

5.26.1.15 Special forms
.......................

These can be used as types in annotations.  They all support
subscription using ‘[]’, but each has a unique syntax.

 -- Data: typing.Union

     Union type; ‘Union[X, Y]’ is equivalent to ‘X | Y’ and means either
     X or Y.

     To define a union, use e.g.  ‘Union[int, str]’ or the shorthand
     ‘int | str’.  Using that shorthand is recommended.  Details:

        * The arguments must be types and there must be at least one.

        * Unions of unions are flattened, e.g.:

               Union[Union[int, str], float] == Union[int, str, float]

          However, this does not apply to unions referenced through a
          type alias, to avoid forcing evaluation of the underlying
          *note TypeAliasType: 458.:

               type A = Union[int, str]
               Union[A, float] != Union[int, str, float]

        * Unions of a single argument vanish, e.g.:

               Union[int] == int  # The constructor actually returns int

        * Redundant arguments are skipped, e.g.:

               Union[int, str, int] == Union[int, str] == int | str

        * When comparing unions, the argument order is ignored, e.g.:

               Union[int, str] == Union[str, int]

        * You cannot subclass or instantiate a ‘Union’.

        * You cannot write ‘Union[X][Y]’.

     Changed in version 3.7: Don’t remove explicit subclasses from
     unions at runtime.

     Changed in version 3.10: Unions can now be written as ‘X | Y’.  See
     *note union type expressions: 7c6.

 -- Data: typing.Optional

     ‘Optional[X]’ is equivalent to ‘X | None’ (or ‘Union[X, None]’).

     Note that this is not the same concept as an optional argument,
     which is one that has a default.  An optional argument with a
     default does not require the ‘Optional’ qualifier on its type
     annotation just because it is optional.  For example:

          def foo(arg: int = 0) -> None:
              ...

     On the other hand, if an explicit value of ‘None’ is allowed, the
     use of ‘Optional’ is appropriate, whether the argument is optional
     or not.  For example:

          def foo(arg: Optional[int] = None) -> None:
              ...

     Changed in version 3.10: Optional can now be written as ‘X | None’.
     See *note union type expressions: 7c6.

 -- Data: typing.Concatenate

     Special form for annotating higher-order functions.

     ‘Concatenate’ can be used in conjunction with *note Callable: 2427.
     and *note ParamSpec: 15e. to annotate a higher-order callable which
     adds, removes, or transforms parameters of another callable.  Usage
     is in the form ‘Concatenate[Arg1Type, Arg2Type, ...,
     ParamSpecVariable]’.  ‘Concatenate’ is currently only valid when
     used as the first argument to a *note Callable: 2427.  The last
     parameter to ‘Concatenate’ must be a ‘ParamSpec’ or ellipsis
     (‘...’).

     For example, to annotate a decorator ‘with_lock’ which provides a
     *note threading.Lock: 178a. to the decorated function,
     ‘Concatenate’ can be used to indicate that ‘with_lock’ expects a
     callable which takes in a ‘Lock’ as the first argument, and returns
     a callable with a different type signature.  In this case, the
     *note ParamSpec: 15e. indicates that the returned callable’s
     parameter types are dependent on the parameter types of the
     callable being passed in:

          from collections.abc import Callable
          from threading import Lock
          from typing import Concatenate

          # Use this lock to ensure that only one thread is executing a function
          # at any time.
          my_lock = Lock()

          def with_lock[**P, R](f: Callable[Concatenate[Lock, P], R]) -> Callable[P, R]:
              '''A type-safe decorator which provides a lock.'''
              def inner(*args: P.args, **kwargs: P.kwargs) -> R:
                  # Provide the lock as the first argument.
                  return f(my_lock, *args, **kwargs)
              return inner

          @with_lock
          def sum_threadsafe(lock: Lock, numbers: list[float]) -> float:
              '''Add a list of numbers together in a thread-safe manner.'''
              with lock:
                  return sum(numbers)

          # We don't need to pass in the lock ourselves thanks to the decorator.
          sum_threadsafe([1.1, 2.2, 3.3])

     Added in version 3.10.

     See also
     ........

        * PEP 612(1) – Parameter Specification Variables (the PEP which
          introduced ‘ParamSpec’ and ‘Concatenate’)

        * *note ParamSpec: 15e.

        * *note Annotating callable objects: 2427.

 -- Data: typing.Literal

     Special typing form to define “literal types”.

     ‘Literal’ can be used to indicate to type checkers that the
     annotated object has a value equivalent to one of the provided
     literals.

     For example:

          def validate_simple(data: Any) -> Literal[True]:  # always returns True
              ...

          type Mode = Literal['r', 'rb', 'w', 'wb']
          def open_helper(file: str, mode: Mode) -> str:
              ...

          open_helper('/some/path', 'r')      # Passes type check
          open_helper('/other/path', 'typo')  # Error in type checker

     ‘Literal[...]’ cannot be subclassed.  At runtime, an arbitrary
     value is allowed as type argument to ‘Literal[...]’, but type
     checkers may impose restrictions.  See PEP 586(2) for more details
     about literal types.

     Additional details:

        * The arguments must be literal values and there must be at
          least one.

        * Nested ‘Literal’ types are flattened, e.g.:

               assert Literal[Literal[1, 2], 3] == Literal[1, 2, 3]

          However, this does not apply to ‘Literal’ types referenced
          through a type alias, to avoid forcing evaluation of the
          underlying *note TypeAliasType: 458.:

               type A = Literal[1, 2]
               assert Literal[A, 3] != Literal[1, 2, 3]

        * Redundant arguments are skipped, e.g.:

               assert Literal[1, 2, 1] == Literal[1, 2]

        * When comparing literals, the argument order is ignored, e.g.:

               assert Literal[1, 2] == Literal[2, 1]

        * You cannot subclass or instantiate a ‘Literal’.

        * You cannot write ‘Literal[X][Y]’.

     Added in version 3.8.

     Changed in version 3.9.1: ‘Literal’ now de-duplicates parameters.
     Equality comparisons of ‘Literal’ objects are no longer order
     dependent.  ‘Literal’ objects will now raise a *note TypeError:
     2c3. exception during equality comparisons if one of their
     parameters are not *note hashable: 613.

 -- Data: typing.ClassVar

     Special type construct to mark class variables.

     As introduced in PEP 526(3), a variable annotation wrapped in
     ClassVar indicates that a given attribute is intended to be used as
     a class variable and should not be set on instances of that class.
     Usage:

          class Starship:
              stats: ClassVar[dict[str, int]] = {} # class variable
              damage: int = 10                     # instance variable

     ‘ClassVar’ accepts only types and cannot be further subscribed.

     ‘ClassVar’ is not a class itself, and should not be used with *note
     isinstance(): 445. or *note issubclass(): 7c5.  ‘ClassVar’ does not
     change Python runtime behavior, but it can be used by third-party
     type checkers.  For example, a type checker might flag the
     following code as an error:

          enterprise_d = Starship(3000)
          enterprise_d.stats = {} # Error, setting class variable on instance
          Starship.stats = {}     # This is OK

     Added in version 3.5.3.

     Changed in version 3.13: ‘ClassVar’ can now be nested in *note
     Final: 267. and vice versa.

 -- Data: typing.Final

     Special typing construct to indicate final names to type checkers.

     Final names cannot be reassigned in any scope.  Final names
     declared in class scopes cannot be overridden in subclasses.

     For example:

          MAX_SIZE: Final = 9000
          MAX_SIZE += 1  # Error reported by type checker

          class Connection:
              TIMEOUT: Final[int] = 10

          class FastConnector(Connection):
              TIMEOUT = 1  # Error reported by type checker

     There is no runtime checking of these properties.  See PEP 591(4)
     for more details.

     Added in version 3.8.

     Changed in version 3.13: ‘Final’ can now be nested in *note
     ClassVar: 266. and vice versa.

 -- Data: typing.Required

     Special typing construct to mark a *note TypedDict: 162. key as
     required.

     This is mainly useful for ‘total=False’ TypedDicts.  See *note
     TypedDict: 162. and PEP 655(5) for more details.

     Added in version 3.11.

 -- Data: typing.NotRequired

     Special typing construct to mark a *note TypedDict: 162. key as
     potentially missing.

     See *note TypedDict: 162. and PEP 655(6) for more details.

     Added in version 3.11.

 -- Data: typing.ReadOnly

     A special typing construct to mark an item of a *note TypedDict:
     162. as read-only.

     For example:

          class Movie(TypedDict):
             title: ReadOnly[str]
             year: int

          def mutate_movie(m: Movie) -> None:
             m["year"] = 1999  # allowed
             m["title"] = "The Matrix"  # typechecker error

     There is no runtime checking for this property.

     See *note TypedDict: 162. and PEP 705(7) for more details.

     Added in version 3.13.

 -- Data: typing.Annotated

     Special typing form to add context-specific metadata to an
     annotation.

     Add metadata ‘x’ to a given type ‘T’ by using the annotation
     ‘Annotated[T, x]’.  Metadata added using ‘Annotated’ can be used by
     static analysis tools or at runtime.  At runtime, the metadata is
     stored in a ‘__metadata__’ attribute.

     If a library or tool encounters an annotation ‘Annotated[T, x]’ and
     has no special logic for the metadata, it should ignore the
     metadata and simply treat the annotation as ‘T’.  As such,
     ‘Annotated’ can be useful for code that wants to use annotations
     for purposes outside Python’s static typing system.

     Using ‘Annotated[T, x]’ as an annotation still allows for static
     typechecking of ‘T’, as type checkers will simply ignore the
     metadata ‘x’.  In this way, ‘Annotated’ differs from the *note
     @no_type_check: 6b7. decorator, which can also be used for adding
     annotations outside the scope of the typing system, but completely
     disables typechecking for a function or class.

     The responsibility of how to interpret the metadata lies with the
     tool or library encountering an ‘Annotated’ annotation.  A tool or
     library encountering an ‘Annotated’ type can scan through the
     metadata elements to determine if they are of interest (e.g., using
     *note isinstance(): 445.).

      -- Describe: Annotated[<type>, <metadata>]

     Here is an example of how you might use ‘Annotated’ to add metadata
     to type annotations if you were doing range analysis:

          @dataclass
          class ValueRange:
              lo: int
              hi: int

          T1 = Annotated[int, ValueRange(-10, 5)]
          T2 = Annotated[T1, ValueRange(-20, 3)]

     The first argument to ‘Annotated’ must be a valid type.  Multiple
     metadata elements can be supplied as ‘Annotated’ supports variadic
     arguments.  The order of the metadata elements is preserved and
     matters for equality checks:

          @dataclass
          class ctype:
               kind: str

          a1 = Annotated[int, ValueRange(3, 10), ctype("char")]
          a2 = Annotated[int, ctype("char"), ValueRange(3, 10)]

          assert a1 != a2  # Order matters

     It is up to the tool consuming the annotations to decide whether
     the client is allowed to add multiple metadata elements to one
     annotation and how to merge those annotations.

     Nested ‘Annotated’ types are flattened.  The order of the metadata
     elements starts with the innermost annotation:

          assert Annotated[Annotated[int, ValueRange(3, 10)], ctype("char")] == Annotated[
              int, ValueRange(3, 10), ctype("char")
          ]

     However, this does not apply to ‘Annotated’ types referenced
     through a type alias, to avoid forcing evaluation of the underlying
     *note TypeAliasType: 458.:

          type From3To10[T] = Annotated[T, ValueRange(3, 10)]
          assert Annotated[From3To10[int], ctype("char")] != Annotated[
             int, ValueRange(3, 10), ctype("char")
          ]

     Duplicated metadata elements are not removed:

          assert Annotated[int, ValueRange(3, 10)] != Annotated[
              int, ValueRange(3, 10), ValueRange(3, 10)
          ]

     ‘Annotated’ can be used with nested and generic aliases:

               @dataclass
               class MaxLen:
                   value: int

               type Vec[T] = Annotated[list[tuple[T, T]], MaxLen(10)]

               # When used in a type annotation, a type checker will treat "V" the same as
               # ``Annotated[list[tuple[int, int]], MaxLen(10)]``:
               type V = Vec[int]

     ‘Annotated’ cannot be used with an unpacked *note TypeVarTuple:
     15f.:

          type Variadic[*Ts] = Annotated[*Ts, Ann1] = Annotated[T1, T2, T3, ..., Ann1]  # NOT valid

     where ‘T1’, ‘T2’, … are *note TypeVars: 15d.  This is invalid as
     only one type should be passed to Annotated.

     By default, *note get_type_hints(): 6b4. strips the metadata from
     annotations.  Pass ‘include_extras=True’ to have the metadata
     preserved:

               >>> from typing import Annotated, get_type_hints
               >>> def func(x: Annotated[int, "metadata"]) -> None: pass
               ...
               >>> get_type_hints(func)
               {'x': <class 'int'>, 'return': <class 'NoneType'>}
               >>> get_type_hints(func, include_extras=True)
               {'x': typing.Annotated[int, 'metadata'], 'return': <class 'NoneType'>}

     At runtime, the metadata associated with an ‘Annotated’ type can be
     retrieved via the ‘__metadata__’ attribute:

               >>> from typing import Annotated
               >>> X = Annotated[int, "very", "important", "metadata"]
               >>> X
               typing.Annotated[int, 'very', 'important', 'metadata']
               >>> X.__metadata__
               ('very', 'important', 'metadata')

     If you want to retrieve the original type wrapped by ‘Annotated’,
     use the ‘__origin__’ attribute:

               >>> from typing import Annotated, get_origin
               >>> Password = Annotated[str, "secret"]
               >>> Password.__origin__
               <class 'str'>

     Note that using *note get_origin(): 2ec. will return ‘Annotated’
     itself:

               >>> get_origin(Password)
               typing.Annotated

     See also
     ........

     PEP 593(8) - Flexible function and variable annotations

          The PEP introducing ‘Annotated’ to the standard library.

     Added in version 3.9.

 -- Data: typing.TypeIs

     Special typing construct for marking user-defined type predicate
     functions.

     ‘TypeIs’ can be used to annotate the return type of a user-defined
     type predicate function.  ‘TypeIs’ only accepts a single type
     argument.  At runtime, functions marked this way should return a
     boolean and take at least one positional argument.

     ‘TypeIs’ aims to benefit 'type narrowing' – a technique used by
     static type checkers to determine a more precise type of an
     expression within a program’s code flow.  Usually type narrowing is
     done by analyzing conditional code flow and applying the narrowing
     to a block of code.  The conditional expression here is sometimes
     referred to as a “type predicate”:

          def is_str(val: str | float):
              # "isinstance" type predicate
              if isinstance(val, str):
                  # Type of ``val`` is narrowed to ``str``
                  ...
              else:
                  # Else, type of ``val`` is narrowed to ``float``.
                  ...

     Sometimes it would be convenient to use a user-defined boolean
     function as a type predicate.  Such a function should use
     ‘TypeIs[...]’ or *note TypeGuard: 164. as its return type to alert
     static type checkers to this intention.  ‘TypeIs’ usually has more
     intuitive behavior than ‘TypeGuard’, but it cannot be used when the
     input and output types are incompatible (e.g., ‘list[object]’ to
     ‘list[int]’) or when the function does not return ‘True’ for all
     instances of the narrowed type.

     Using ‘-> TypeIs[NarrowedType]’ tells the static type checker that
     for a given function:

       1. The return value is a boolean.

       2. If the return value is ‘True’, the type of its argument is the
          intersection of the argument’s original type and
          ‘NarrowedType’.

       3. If the return value is ‘False’, the type of its argument is
          narrowed to exclude ‘NarrowedType’.

     For example:

          from typing import assert_type, final, TypeIs

          class Parent: pass
          class Child(Parent): pass
          @final
          class Unrelated: pass

          def is_parent(val: object) -> TypeIs[Parent]:
              return isinstance(val, Parent)

          def run(arg: Child | Unrelated):
              if is_parent(arg):
                  # Type of ``arg`` is narrowed to the intersection
                  # of ``Parent`` and ``Child``, which is equivalent to
                  # ``Child``.
                  assert_type(arg, Child)
              else:
                  # Type of ``arg`` is narrowed to exclude ``Parent``,
                  # so only ``Unrelated`` is left.
                  assert_type(arg, Unrelated)

     The type inside ‘TypeIs’ must be consistent with the type of the
     function’s argument; if it is not, static type checkers will raise
     an error.  An incorrectly written ‘TypeIs’ function can lead to
     unsound behavior in the type system; it is the user’s
     responsibility to write such functions in a type-safe manner.

     If a ‘TypeIs’ function is a class or instance method, then the type
     in ‘TypeIs’ maps to the type of the second parameter (after ‘cls’
     or ‘self’).

     In short, the form ‘def foo(arg: TypeA) -> TypeIs[TypeB]: ...’,
     means that if ‘foo(arg)’ returns ‘True’, then ‘arg’ is an instance
     of ‘TypeB’, and if it returns ‘False’, it is not an instance of
     ‘TypeB’.

     ‘TypeIs’ also works with type variables.  For more information, see
     PEP 742(9) (Narrowing types with ‘TypeIs’).

     Added in version 3.13.

 -- Data: typing.TypeGuard

     Special typing construct for marking user-defined type predicate
     functions.

     Type predicate functions are user-defined functions that return
     whether their argument is an instance of a particular type.
     ‘TypeGuard’ works similarly to *note TypeIs: 163, but has subtly
     different effects on type checking behavior (see below).

     Using ‘-> TypeGuard’ tells the static type checker that for a given
     function:

       1. The return value is a boolean.

       2. If the return value is ‘True’, the type of its argument is the
          type inside ‘TypeGuard’.

     ‘TypeGuard’ also works with type variables.  See PEP 647(10) for
     more details.

     For example:

          def is_str_list(val: list[object]) -> TypeGuard[list[str]]:
              '''Determines whether all objects in the list are strings'''
              return all(isinstance(x, str) for x in val)

          def func1(val: list[object]):
              if is_str_list(val):
                  # Type of ``val`` is narrowed to ``list[str]``.
                  print(" ".join(val))
              else:
                  # Type of ``val`` remains as ``list[object]``.
                  print("Not a list of strings!")

     ‘TypeIs’ and ‘TypeGuard’ differ in the following ways:

        * ‘TypeIs’ requires the narrowed type to be a subtype of the
          input type, while ‘TypeGuard’ does not.  The main reason is to
          allow for things like narrowing ‘list[object]’ to ‘list[str]’
          even though the latter is not a subtype of the former, since
          ‘list’ is invariant.

        * When a ‘TypeGuard’ function returns ‘True’, type checkers
          narrow the type of the variable to exactly the ‘TypeGuard’
          type.  When a ‘TypeIs’ function returns ‘True’, type checkers
          can infer a more precise type combining the previously known
          type of the variable with the ‘TypeIs’ type.  (Technically,
          this is known as an intersection type.)

        * When a ‘TypeGuard’ function returns ‘False’, type checkers
          cannot narrow the type of the variable at all.  When a
          ‘TypeIs’ function returns ‘False’, type checkers can narrow
          the type of the variable to exclude the ‘TypeIs’ type.

     Added in version 3.10.

 -- Data: typing.Unpack

     Typing operator to conceptually mark an object as having been
     unpacked.

     For example, using the unpack operator ‘*’ on a *note type variable
     tuple: 41c0. is equivalent to using ‘Unpack’ to mark the type
     variable tuple as having been unpacked:

          Ts = TypeVarTuple('Ts')
          tup: tuple[*Ts]
          # Effectively does:
          tup: tuple[Unpack[Ts]]

     In fact, ‘Unpack’ can be used interchangeably with ‘*’ in the
     context of *note typing.TypeVarTuple: 15f. and *note
     builtins.tuple: 373. types.  You might see ‘Unpack’ being used
     explicitly in older versions of Python, where ‘*’ couldn’t be used
     in certain places:

          # In older versions of Python, TypeVarTuple and Unpack
          # are located in the `typing_extensions` backports package.
          from typing_extensions import TypeVarTuple, Unpack

          Ts = TypeVarTuple('Ts')
          tup: tuple[*Ts]         # Syntax error on Python <= 3.10!
          tup: tuple[Unpack[Ts]]  # Semantically equivalent, and backwards-compatible

     ‘Unpack’ can also be used along with *note typing.TypedDict: 162.
     for typing ‘**kwargs’ in a function signature:

          from typing import TypedDict, Unpack

          class Movie(TypedDict):
              name: str
              year: int

          # This function expects two keyword arguments - `name` of type `str`
          # and `year` of type `int`.
          def foo(**kwargs: Unpack[Movie]): ...

     See PEP 692(11) for more details on using ‘Unpack’ for ‘**kwargs’
     typing.

     Added in version 3.11.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0612/

   (2) https://peps.python.org/pep-0586/

   (3) https://peps.python.org/pep-0526/

   (4) https://peps.python.org/pep-0591/

   (5) https://peps.python.org/pep-0655/

   (6) https://peps.python.org/pep-0655/

   (7) https://peps.python.org/pep-0705/

   (8) https://peps.python.org/pep-0593/

   (9) https://peps.python.org/pep-0742/

   (10) https://peps.python.org/pep-0647/

   (11) https://peps.python.org/pep-0692/


File: python.info,  Node: Building generic types and type aliases,  Next: Other special directives,  Prev: Special forms,  Up: Special typing primitives

5.26.1.16 Building generic types and type aliases
.................................................

The following classes should not be used directly as annotations.  Their
intended purpose is to be building blocks for creating generic types and
type aliases.

These objects can be created through special syntax (*note type
parameter lists: 2b3. and the *note type: 43b. statement).  For
compatibility with Python 3.11 and earlier, they can also be created
without the dedicated syntax, as documented below.

 -- Class: typing.Generic

     Abstract base class for generic types.

     A generic type is typically declared by adding a list of type
     parameters after the class name:

          class Mapping[KT, VT]:
              def __getitem__(self, key: KT) -> VT:
                  ...
                  # Etc.

     Such a class implicitly inherits from ‘Generic’.  The runtime
     semantics of this syntax are discussed in the *note Language
     Reference: 455.

     This class can then be used as follows:

          def lookup_name[X, Y](mapping: Mapping[X, Y], key: X, default: Y) -> Y:
              try:
                  return mapping[key]
              except KeyError:
                  return default

     Here the brackets after the function name indicate a *note generic
     function: 456.

     For backwards compatibility, generic classes can also be declared
     by explicitly inheriting from ‘Generic’.  In this case, the type
     parameters must be declared separately:

          KT = TypeVar('KT')
          VT = TypeVar('VT')

          class Mapping(Generic[KT, VT]):
              def __getitem__(self, key: KT) -> VT:
                  ...
                  # Etc.

 -- Class: typing.TypeVar (name, *constraints, bound=None,
          covariant=False, contravariant=False, infer_variance=False,
          default=typing.NoDefault)

     Type variable.

     The preferred way to construct a type variable is via the dedicated
     syntax for *note generic functions: 456, *note generic classes:
     455, and *note generic type aliases: 459.:

          class Sequence[T]:  # T is a TypeVar
              ...

     This syntax can also be used to create bounded and constrained type
     variables:

          class StrSequence[S: str]:  # S is a TypeVar with a `str` upper bound;
              ...                     # we can say that S is "bounded by `str`"


          class StrOrBytesSequence[A: (str, bytes)]:  # A is a TypeVar constrained to str or bytes
              ...

     However, if desired, reusable type variables can also be
     constructed manually, like so:

          T = TypeVar('T')  # Can be anything
          S = TypeVar('S', bound=str)  # Can be any subtype of str
          A = TypeVar('A', str, bytes)  # Must be exactly str or bytes

     Type variables exist primarily for the benefit of static type
     checkers.  They serve as the parameters for generic types as well
     as for generic function and type alias definitions.  See *note
     Generic: 15fb. for more information on generic types.  Generic
     functions work as follows:

          def repeat[T](x: T, n: int) -> Sequence[T]:
              """Return a list containing n references to x."""
              return [x]*n


          def print_capitalized[S: str](x: S) -> S:
              """Print x capitalized, and return x."""
              print(x.capitalize())
              return x


          def concatenate[A: (str, bytes)](x: A, y: A) -> A:
              """Add two strings or bytes objects together."""
              return x + y

     Note that type variables can be 'bounded', 'constrained', or
     neither, but cannot be both bounded 'and' constrained.

     The variance of type variables is inferred by type checkers when
     they are created through the *note type parameter syntax: 2b3. or
     when ‘infer_variance=True’ is passed.  Manually created type
     variables may be explicitly marked covariant or contravariant by
     passing ‘covariant=True’ or ‘contravariant=True’.  By default,
     manually created type variables are invariant.  See PEP 484(1) and
     PEP 695(2) for more details.

     Bounded type variables and constrained type variables have
     different semantics in several important ways.  Using a 'bounded'
     type variable means that the ‘TypeVar’ will be solved using the
     most specific type possible:

          x = print_capitalized('a string')
          reveal_type(x)  # revealed type is str

          class StringSubclass(str):
              pass

          y = print_capitalized(StringSubclass('another string'))
          reveal_type(y)  # revealed type is StringSubclass

          z = print_capitalized(45)  # error: int is not a subtype of str

     The upper bound of a type variable can be a concrete type, abstract
     type (ABC or Protocol), or even a union of types:

          # Can be anything with an __abs__ method
          def print_abs[T: SupportsAbs](arg: T) -> None:
              print("Absolute value:", abs(arg))

          U = TypeVar('U', bound=str|bytes)  # Can be any subtype of the union str|bytes
          V = TypeVar('V', bound=SupportsAbs)  # Can be anything with an __abs__ method
     Using a 'constrained' type variable, however, means that the
     ‘TypeVar’ can only ever be solved as being exactly one of the
     constraints given:

          a = concatenate('one', 'two')
          reveal_type(a)  # revealed type is str

          b = concatenate(StringSubclass('one'), StringSubclass('two'))
          reveal_type(b)  # revealed type is str, despite StringSubclass being passed in

          c = concatenate('one', b'two')  # error: type variable 'A' can be either str or bytes in a function call, but not both

     At runtime, ‘isinstance(x, T)’ will raise *note TypeError: 2c3.

      -- Attribute: __name__

          The name of the type variable.

      -- Attribute: __covariant__

          Whether the type var has been explicitly marked as covariant.

      -- Attribute: __contravariant__

          Whether the type var has been explicitly marked as
          contravariant.

      -- Attribute: __infer_variance__

          Whether the type variable’s variance should be inferred by
          type checkers.

          Added in version 3.12.

      -- Attribute: __bound__

          The upper bound of the type variable, if any.

          Changed in version 3.12: For type variables created through
          *note type parameter syntax: 2b3, the bound is evaluated only
          when the attribute is accessed, not when the type variable is
          created (see *note Lazy evaluation: 45a.).

      -- Attribute: __constraints__

          A tuple containing the constraints of the type variable, if
          any.

          Changed in version 3.12: For type variables created through
          *note type parameter syntax: 2b3, the constraints are
          evaluated only when the attribute is accessed, not when the
          type variable is created (see *note Lazy evaluation: 45a.).

      -- Attribute: __default__

          The default value of the type variable, or *note
          typing.NoDefault: 262. if it has no default.

          Added in version 3.13.

      -- Method: has_default ()

          Return whether or not the type variable has a default value.
          This is equivalent to checking whether *note __default__:
          41c8. is not the *note typing.NoDefault: 262. singleton,
          except that it does not force evaluation of the *note lazily
          evaluated: 45a. default value.

          Added in version 3.13.

     Changed in version 3.12: Type variables can now be declared using
     the *note type parameter: 2b3. syntax introduced by PEP 695(3).
     The ‘infer_variance’ parameter was added.

     Changed in version 3.13: Support for default values was added.

 -- Class: typing.TypeVarTuple (name, *, default=typing.NoDefault)

     Type variable tuple.  A specialized form of *note type variable:
     41b7. that enables 'variadic' generics.

     Type variable tuples can be declared in *note type parameter lists:
     2b3. using a single asterisk (‘*’) before the name:

          def move_first_element_to_last[T, *Ts](tup: tuple[T, *Ts]) -> tuple[*Ts, T]:
              return (*tup[1:], tup[0])

     Or by explicitly invoking the ‘TypeVarTuple’ constructor:

          T = TypeVar("T")
          Ts = TypeVarTuple("Ts")

          def move_first_element_to_last(tup: tuple[T, *Ts]) -> tuple[*Ts, T]:
              return (*tup[1:], tup[0])

     A normal type variable enables parameterization with a single type.
     A type variable tuple, in contrast, allows parameterization with an
     'arbitrary' number of types by acting like an 'arbitrary' number of
     type variables wrapped in a tuple.  For example:

          # T is bound to int, Ts is bound to ()
          # Return value is (1,), which has type tuple[int]
          move_first_element_to_last(tup=(1,))

          # T is bound to int, Ts is bound to (str,)
          # Return value is ('spam', 1), which has type tuple[str, int]
          move_first_element_to_last(tup=(1, 'spam'))

          # T is bound to int, Ts is bound to (str, float)
          # Return value is ('spam', 3.0, 1), which has type tuple[str, float, int]
          move_first_element_to_last(tup=(1, 'spam', 3.0))

          # This fails to type check (and fails at runtime)
          # because tuple[()] is not compatible with tuple[T, *Ts]
          # (at least one element is required)
          move_first_element_to_last(tup=())

     Note the use of the unpacking operator ‘*’ in ‘tuple[T, *Ts]’.
     Conceptually, you can think of ‘Ts’ as a tuple of type variables
     ‘(T1, T2, ...)’.  ‘tuple[T, *Ts]’ would then become ‘tuple[T, *(T1,
     T2, ...)]’, which is equivalent to ‘tuple[T, T1, T2, ...]’.  (Note
     that in older versions of Python, you might see this written using
     *note Unpack: 1738. instead, as ‘Unpack[Ts]’.)

     Type variable tuples must 'always' be unpacked.  This helps
     distinguish type variable tuples from normal type variables:

          x: Ts          # Not valid
          x: tuple[Ts]   # Not valid
          x: tuple[*Ts]  # The correct way to do it

     Type variable tuples can be used in the same contexts as normal
     type variables.  For example, in class definitions, arguments, and
     return types:

          class Array[*Shape]:
              def __getitem__(self, key: tuple[*Shape]) -> float: ...
              def __abs__(self) -> "Array[*Shape]": ...
              def get_shape(self) -> tuple[*Shape]: ...

     Type variable tuples can be happily combined with normal type
     variables:

          class Array[DType, *Shape]:  # This is fine
              pass

          class Array2[*Shape, DType]:  # This would also be fine
              pass

          class Height: ...
          class Width: ...

          float_array_1d: Array[float, Height] = Array()     # Totally fine
          int_array_2d: Array[int, Height, Width] = Array()  # Yup, fine too

     However, note that at most one type variable tuple may appear in a
     single list of type arguments or type parameters:

          x: tuple[*Ts, *Ts]            # Not valid
          class Array[*Shape, *Shape]:  # Not valid
              pass

     Finally, an unpacked type variable tuple can be used as the type
     annotation of ‘*args’:

          def call_soon[*Ts](
              callback: Callable[[*Ts], None],
              *args: *Ts
          ) -> None:
              ...
              callback(*args)

     In contrast to non-unpacked annotations of ‘*args’ - e.g.  ‘*args:
     int’, which would specify that 'all' arguments are ‘int’ - ‘*args:
     *Ts’ enables reference to the types of the 'individual' arguments
     in ‘*args’.  Here, this allows us to ensure the types of the
     ‘*args’ passed to ‘call_soon’ match the types of the (positional)
     arguments of ‘callback’.

     See PEP 646(4) for more details on type variable tuples.

      -- Attribute: __name__

          The name of the type variable tuple.

      -- Attribute: __default__

          The default value of the type variable tuple, or *note
          typing.NoDefault: 262. if it has no default.

          Added in version 3.13.

      -- Method: has_default ()

          Return whether or not the type variable tuple has a default
          value.  This is equivalent to checking whether *note
          __default__: 41cb. is not the *note typing.NoDefault: 262.
          singleton, except that it does not force evaluation of the
          *note lazily evaluated: 45a. default value.

          Added in version 3.13.

     Added in version 3.11.

     Changed in version 3.12: Type variable tuples can now be declared
     using the *note type parameter: 2b3. syntax introduced by PEP
     695(5).

     Changed in version 3.13: Support for default values was added.

 -- Class: typing.ParamSpec (name, *, bound=None, covariant=False,
          contravariant=False, default=typing.NoDefault)

     Parameter specification variable.  A specialized version of *note
     type variables: 41b7.

     In *note type parameter lists: 2b3, parameter specifications can be
     declared with two asterisks (‘**’):

          type IntFunc[**P] = Callable[P, int]

     For compatibility with Python 3.11 and earlier, ‘ParamSpec’ objects
     can also be created as follows:

          P = ParamSpec('P')

     Parameter specification variables exist primarily for the benefit
     of static type checkers.  They are used to forward the parameter
     types of one callable to another callable – a pattern commonly
     found in higher order functions and decorators.  They are only
     valid when used in ‘Concatenate’, or as the first argument to
     ‘Callable’, or as parameters for user-defined Generics.  See *note
     Generic: 15fb. for more information on generic types.

     For example, to add basic logging to a function, one can create a
     decorator ‘add_logging’ to log function calls.  The parameter
     specification variable tells the type checker that the callable
     passed into the decorator and the new callable returned by it have
     inter-dependent type parameters:

          from collections.abc import Callable
          import logging

          def add_logging[T, **P](f: Callable[P, T]) -> Callable[P, T]:
              '''A type-safe decorator to add logging to a function.'''
              def inner(*args: P.args, **kwargs: P.kwargs) -> T:
                  logging.info(f'{f.__name__} was called')
                  return f(*args, **kwargs)
              return inner

          @add_logging
          def add_two(x: float, y: float) -> float:
              '''Add two numbers together.'''
              return x + y

     Without ‘ParamSpec’, the simplest way to annotate this previously
     was to use a *note TypeVar: 15d. with upper bound ‘Callable[...,
     Any]’.  However this causes two problems:

       1. The type checker can’t type check the ‘inner’ function because
          ‘*args’ and ‘**kwargs’ have to be typed *note Any: 6af.

       2. *note cast(): 41cd. may be required in the body of the
          ‘add_logging’ decorator when returning the ‘inner’ function,
          or the static type checker must be told to ignore the ‘return
          inner’.

      -- Attribute: args

      -- Attribute: kwargs

          Since ‘ParamSpec’ captures both positional and keyword
          parameters, ‘P.args’ and ‘P.kwargs’ can be used to split a
          ‘ParamSpec’ into its components.  ‘P.args’ represents the
          tuple of positional parameters in a given call and should only
          be used to annotate ‘*args’.  ‘P.kwargs’ represents the
          mapping of keyword parameters to their values in a given call,
          and should be only be used to annotate ‘**kwargs’.  Both
          attributes require the annotated parameter to be in scope.  At
          runtime, ‘P.args’ and ‘P.kwargs’ are instances respectively of
          *note ParamSpecArgs: 7ca. and *note ParamSpecKwargs: 7cb.

      -- Attribute: __name__

          The name of the parameter specification.

      -- Attribute: __default__

          The default value of the parameter specification, or *note
          typing.NoDefault: 262. if it has no default.

          Added in version 3.13.

      -- Method: has_default ()

          Return whether or not the parameter specification has a
          default value.  This is equivalent to checking whether *note
          __default__: 41d1. is not the *note typing.NoDefault: 262.
          singleton, except that it does not force evaluation of the
          *note lazily evaluated: 45a. default value.

          Added in version 3.13.

     Parameter specification variables created with ‘covariant=True’ or
     ‘contravariant=True’ can be used to declare covariant or
     contravariant generic types.  The ‘bound’ argument is also
     accepted, similar to *note TypeVar: 15d.  However the actual
     semantics of these keywords are yet to be decided.

     Added in version 3.10.

     Changed in version 3.12: Parameter specifications can now be
     declared using the *note type parameter: 2b3. syntax introduced by
     PEP 695(6).

     Changed in version 3.13: Support for default values was added.

          Note: Only parameter specification variables defined in global
          scope can be pickled.

     See also
     ........

        * PEP 612(7) – Parameter Specification Variables (the PEP which
          introduced ‘ParamSpec’ and ‘Concatenate’)

        * *note Concatenate: 7c8.

        * *note Annotating callable objects: 2427.

 -- Data: typing.ParamSpecArgs
 -- Data: typing.ParamSpecKwargs

     Arguments and keyword arguments attributes of a *note ParamSpec:
     15e.  The ‘P.args’ attribute of a ‘ParamSpec’ is an instance of
     ‘ParamSpecArgs’, and ‘P.kwargs’ is an instance of
     ‘ParamSpecKwargs’.  They are intended for runtime introspection and
     have no special meaning to static type checkers.

     Calling *note get_origin(): 2ec. on either of these objects will
     return the original ‘ParamSpec’:

          >>> from typing import ParamSpec, get_origin
          >>> P = ParamSpec("P")
          >>> get_origin(P.args) is P
          True
          >>> get_origin(P.kwargs) is P
          True

     Added in version 3.10.

 -- Class: typing.TypeAliasType (name, value, *, type_params=())

     The type of type aliases created through the *note type: 43b.
     statement.

     Example:

          >>> type Alias = int
          >>> type(Alias)
          <class 'typing.TypeAliasType'>

     Added in version 3.12.

      -- Attribute: __name__

          The name of the type alias:

               >>> type Alias = int
               >>> Alias.__name__
               'Alias'

      -- Attribute: __module__

          The name of the module in which the type alias was defined:

               >>> type Alias = int
               >>> Alias.__module__
               '__main__'

      -- Attribute: __type_params__

          The type parameters of the type alias, or an empty tuple if
          the alias is not generic:

               >>> type ListOrSet[T] = list[T] | set[T]
               >>> ListOrSet.__type_params__
               (T,)
               >>> type NotGeneric = int
               >>> NotGeneric.__type_params__
               ()

      -- Attribute: __value__

          The type alias’s value.  This is *note lazily evaluated: 45a,
          so names used in the definition of the alias are not resolved
          until the ‘__value__’ attribute is accessed:

               >>> type Mutually = Recursive
               >>> type Recursive = Mutually
               >>> Mutually
               Mutually
               >>> Recursive
               Recursive
               >>> Mutually.__value__
               Recursive
               >>> Recursive.__value__
               Mutually

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0695/

   (3) https://peps.python.org/pep-0695/

   (4) https://peps.python.org/pep-0646/

   (5) https://peps.python.org/pep-0695/

   (6) https://peps.python.org/pep-0695/

   (7) https://peps.python.org/pep-0612/


File: python.info,  Node: Other special directives,  Prev: Building generic types and type aliases,  Up: Special typing primitives

5.26.1.17 Other special directives
..................................

These functions and classes should not be used directly as annotations.
Their intended purpose is to be building blocks for creating and
declaring types.

 -- Class: typing.NamedTuple

     Typed version of *note collections.namedtuple(): 1ca.

     Usage:

          class Employee(NamedTuple):
              name: str
              id: int

     This is equivalent to:

          Employee = collections.namedtuple('Employee', ['name', 'id'])

     To give a field a default value, you can assign to it in the class
     body:

          class Employee(NamedTuple):
              name: str
              id: int = 3

          employee = Employee('Guido')
          assert employee.id == 3

     Fields with a default value must come after any fields without a
     default.

     The resulting class has an extra attribute ‘__annotations__’ giving
     a dict that maps the field names to the field types.  (The field
     names are in the ‘_fields’ attribute and the default values are in
     the ‘_field_defaults’ attribute, both of which are part of the
     *note namedtuple(): 1ca. API.)

     ‘NamedTuple’ subclasses can also have docstrings and methods:

          class Employee(NamedTuple):
              """Represents an employee."""
              name: str
              id: int = 3

              def __repr__(self) -> str:
                  return f'<Employee {self.name}, id={self.id}>'

     ‘NamedTuple’ subclasses can be generic:

          class Group[T](NamedTuple):
              key: T
              group: list[T]

     Backward-compatible usage:

          # For creating a generic NamedTuple on Python 3.11
          T = TypeVar("T")

          class Group(NamedTuple, Generic[T]):
              key: T
              group: list[T]

          # A functional syntax is also supported
          Employee = NamedTuple('Employee', [('name', str), ('id', int)])

     Changed in version 3.6: Added support for PEP 526(1) variable
     annotation syntax.

     Changed in version 3.6.1: Added support for default values,
     methods, and docstrings.

     Changed in version 3.8: The ‘_field_types’ and ‘__annotations__’
     attributes are now regular dictionaries instead of instances of
     ‘OrderedDict’.

     Changed in version 3.9: Removed the ‘_field_types’ attribute in
     favor of the more standard ‘__annotations__’ attribute which has
     the same information.

     Changed in version 3.9: ‘NamedTuple’ is now a function rather than
     a class.  It can still be used as a class base, as described above.

     Changed in version 3.11: Added support for generic namedtuples.

     Deprecated since version 3.13, will be removed in version 3.15: The
     undocumented keyword argument syntax for creating NamedTuple
     classes (‘NT = NamedTuple("NT", x=int)’) is deprecated, and will be
     disallowed in 3.15.  Use the class-based syntax or the functional
     syntax instead.

     Deprecated since version 3.13, will be removed in version 3.15:
     When using the functional syntax to create a NamedTuple class,
     failing to pass a value to the ‘fields’ parameter (‘NT =
     NamedTuple("NT")’) is deprecated.  Passing ‘None’ to the ‘fields’
     parameter (‘NT = NamedTuple("NT", None)’) is also deprecated.  Both
     will be disallowed in Python 3.15.  To create a NamedTuple class
     with 0 fields, use ‘class NT(NamedTuple): pass’ or ‘NT =
     NamedTuple("NT", [])’.

 -- Class: typing.NewType (name, tp)

     Helper class to create low-overhead *note distinct types: 41ac.

     A ‘NewType’ is considered a distinct type by a typechecker.  At
     runtime, however, calling a ‘NewType’ returns its argument
     unchanged.

     Usage:

          UserId = NewType('UserId', int)  # Declare the NewType "UserId"
          first_user = UserId(1)  # "UserId" returns the argument unchanged at runtime

      -- Attribute: __module__

          The name of the module in which the new type is defined.

      -- Attribute: __name__

          The name of the new type.

      -- Attribute: __supertype__

          The type that the new type is based on.

     Added in version 3.5.2.

     Changed in version 3.10: ‘NewType’ is now a class rather than a
     function.

 -- Class: typing.Protocol (Generic)

     Base class for protocol classes.

     Protocol classes are defined like this:

          class Proto(Protocol):
              def meth(self) -> int:
                  ...

     Such classes are primarily used with static type checkers that
     recognize structural subtyping (static duck-typing), for example:

          class C:
              def meth(self) -> int:
                  return 0

          def func(x: Proto) -> int:
              return x.meth()

          func(C())  # Passes static type check

     See PEP 544(2) for more details.  Protocol classes decorated with
     *note runtime_checkable(): 446. (described later) act as
     simple-minded runtime protocols that check only the presence of
     given attributes, ignoring their type signatures.  Protocol classes
     without this decorator cannot be used as the second argument to
     *note isinstance(): 445. or *note issubclass(): 7c5.

     Protocol classes can be generic, for example:

          class GenProto[T](Protocol):
              def meth(self) -> T:
                  ...

     In code that needs to be compatible with Python 3.11 or older,
     generic Protocols can be written as follows:

          T = TypeVar("T")

          class GenProto(Protocol[T]):
              def meth(self) -> T:
                  ...

     Added in version 3.8.

 -- Function: @typing.runtime_checkable

     Mark a protocol class as a runtime protocol.

     Such a protocol can be used with *note isinstance(): 445. and *note
     issubclass(): 7c5.  This allows a simple-minded structural check,
     very similar to “one trick ponies” in *note collections.abc: 1e.
     such as *note Iterable: 2405.  For example:

          @runtime_checkable
          class Closable(Protocol):
              def close(self): ...

          assert isinstance(open('/some/file'), Closable)

          @runtime_checkable
          class Named(Protocol):
              name: str

          import threading
          assert isinstance(threading.Thread(name='Bob'), Named)

     This decorator raises *note TypeError: 2c3. when applied to a
     non-protocol class.

          Note: ‘runtime_checkable()’ will check only the presence of
          the required methods or attributes, not their type signatures
          or types.  For example, *note ssl.SSLObject: b9f. is a class,
          therefore it passes an *note issubclass(): 7c5. check against
          *note Callable: 2427.  However, the ‘ssl.SSLObject.__init__’
          method exists only to raise a *note TypeError: 2c3. with a
          more informative message, therefore making it impossible to
          call (instantiate) ‘ssl.SSLObject’.

          Note: An *note isinstance(): 445. check against a
          runtime-checkable protocol can be surprisingly slow compared
          to an ‘isinstance()’ check against a non-protocol class.
          Consider using alternative idioms such as *note hasattr():
          4d5. calls for structural checks in performance-sensitive
          code.

     Added in version 3.8.

     Changed in version 3.12: The internal implementation of *note
     isinstance(): 445. checks against runtime-checkable protocols now
     uses *note inspect.getattr_static(): 497. to look up attributes
     (previously, *note hasattr(): 4d5. was used).  As a result, some
     objects which used to be considered instances of a
     runtime-checkable protocol may no longer be considered instances of
     that protocol on Python 3.12+, and vice versa.  Most users are
     unlikely to be affected by this change.

     Changed in version 3.12: The members of a runtime-checkable
     protocol are now considered “frozen” at runtime as soon as the
     class has been created.  Monkey-patching attributes onto a
     runtime-checkable protocol will still work, but will have no impact
     on *note isinstance(): 445. checks comparing objects to the
     protocol.  See *note What’s new in Python 3.12: 4d4. for more
     details.

 -- Class: typing.TypedDict (dict)

     Special construct to add type hints to a dictionary.  At runtime
     “‘TypedDict’ instances” are simply *note dicts: 256.

     ‘TypedDict’ declares a dictionary type that expects all of its
     instances to have a certain set of keys, where each key is
     associated with a value of a consistent type.  This expectation is
     not checked at runtime but is only enforced by type checkers.
     Usage:

          class Point2D(TypedDict):
              x: int
              y: int
              label: str

          a: Point2D = {'x': 1, 'y': 2, 'label': 'good'}  # OK
          b: Point2D = {'z': 3, 'label': 'bad'}           # Fails type check

          assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')

     An alternative way to create a ‘TypedDict’ is by using
     function-call syntax.  The second argument must be a literal *note
     dict: 256.:

          Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})

     This functional syntax allows defining keys which are not valid
     *note identifiers: 2040, for example because they are keywords or
     contain hyphens, or when key names must not be *note mangled: 1e5b.
     like regular private names:

          # raises SyntaxError
          class Point2D(TypedDict):
              in: int  # 'in' is a keyword
              x-y: int  # name with hyphens

          class Definition(TypedDict):
              __schema: str  # mangled to `_Definition__schema`

          # OK, functional syntax
          Point2D = TypedDict('Point2D', {'in': int, 'x-y': int})
          Definition = TypedDict('Definition', {'__schema': str})  # not mangled

     By default, all keys must be present in a ‘TypedDict’.  It is
     possible to mark individual keys as non-required using *note
     NotRequired: 5c8.:

          class Point2D(TypedDict):
              x: int
              y: int
              label: NotRequired[str]

          # Alternative syntax
          Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': NotRequired[str]})

     This means that a ‘Point2D’ ‘TypedDict’ can have the ‘label’ key
     omitted.

     It is also possible to mark all keys as non-required by default by
     specifying a totality of ‘False’:

          class Point2D(TypedDict, total=False):
              x: int
              y: int

          # Alternative syntax
          Point2D = TypedDict('Point2D', {'x': int, 'y': int}, total=False)

     This means that a ‘Point2D’ ‘TypedDict’ can have any of the keys
     omitted.  A type checker is only expected to support a literal
     ‘False’ or ‘True’ as the value of the ‘total’ argument.  ‘True’ is
     the default, and makes all items defined in the class body
     required.

     Individual keys of a ‘total=False’ ‘TypedDict’ can be marked as
     required using *note Required: 5c7.:

          class Point2D(TypedDict, total=False):
              x: Required[int]
              y: Required[int]
              label: str

          # Alternative syntax
          Point2D = TypedDict('Point2D', {
              'x': Required[int],
              'y': Required[int],
              'label': str
          }, total=False)

     It is possible for a ‘TypedDict’ type to inherit from one or more
     other ‘TypedDict’ types using the class-based syntax.  Usage:

          class Point3D(Point2D):
              z: int

     ‘Point3D’ has three items: ‘x’, ‘y’ and ‘z’.  It is equivalent to
     this definition:

          class Point3D(TypedDict):
              x: int
              y: int
              z: int

     A ‘TypedDict’ cannot inherit from a non-‘TypedDict’ class, except
     for *note Generic: 15fb.  For example:

          class X(TypedDict):
              x: int

          class Y(TypedDict):
              y: int

          class Z(object): pass  # A non-TypedDict class

          class XY(X, Y): pass  # OK

          class XZ(X, Z): pass  # raises TypeError

     A ‘TypedDict’ can be generic:

          class Group[T](TypedDict):
              key: T
              group: list[T]

     To create a generic ‘TypedDict’ that is compatible with Python 3.11
     or lower, inherit from *note Generic: 15fb. explicitly:

          T = TypeVar("T")

          class Group(TypedDict, Generic[T]):
              key: T
              group: list[T]

     A ‘TypedDict’ can be introspected via annotations dicts (see *note
     Annotations Best Practices: 7dd. for more information on
     annotations best practices), *note __total__: 41db, *note
     __required_keys__: 41dc, and *note __optional_keys__: 41dd.

      -- Attribute: __total__

          ‘Point2D.__total__’ gives the value of the ‘total’ argument.
          Example:

               >>> from typing import TypedDict
               >>> class Point2D(TypedDict): pass
               >>> Point2D.__total__
               True
               >>> class Point2D(TypedDict, total=False): pass
               >>> Point2D.__total__
               False
               >>> class Point3D(Point2D): pass
               >>> Point3D.__total__
               True

          This attribute reflects 'only' the value of the ‘total’
          argument to the current ‘TypedDict’ class, not whether the
          class is semantically total.  For example, a ‘TypedDict’ with
          ‘__total__’ set to ‘True’ may have keys marked with *note
          NotRequired: 5c8, or it may inherit from another ‘TypedDict’
          with ‘total=False’.  Therefore, it is generally better to use
          *note __required_keys__: 41dc. and *note __optional_keys__:
          41dd. for introspection.

      -- Attribute: __required_keys__

          Added in version 3.9.

      -- Attribute: __optional_keys__

          ‘Point2D.__required_keys__’ and ‘Point2D.__optional_keys__’
          return *note frozenset: 5dd. objects containing required and
          non-required keys, respectively.

          Keys marked with *note Required: 5c7. will always appear in
          ‘__required_keys__’ and keys marked with *note NotRequired:
          5c8. will always appear in ‘__optional_keys__’.

          For backwards compatibility with Python 3.10 and below, it is
          also possible to use inheritance to declare both required and
          non-required keys in the same ‘TypedDict’ .  This is done by
          declaring a ‘TypedDict’ with one value for the ‘total’
          argument and then inheriting from it in another ‘TypedDict’
          with a different value for ‘total’:

               >>> class Point2D(TypedDict, total=False):
               ...     x: int
               ...     y: int
               ...
               >>> class Point3D(Point2D):
               ...     z: int
               ...
               >>> Point3D.__required_keys__ == frozenset({'z'})
               True
               >>> Point3D.__optional_keys__ == frozenset({'x', 'y'})
               True

          Added in version 3.9.

               Note: If ‘from __future__ import annotations’ is used or
               if annotations are given as strings, annotations are not
               evaluated when the ‘TypedDict’ is defined.  Therefore,
               the runtime introspection that ‘__required_keys__’ and
               ‘__optional_keys__’ rely on may not work properly, and
               the values of the attributes may be incorrect.

     Support for *note ReadOnly: 161. is reflected in the following
     attributes:

      -- Attribute: __readonly_keys__

          A *note frozenset: 5dd. containing the names of all read-only
          keys.  Keys are read-only if they carry the *note ReadOnly:
          161. qualifier.

          Added in version 3.13.

      -- Attribute: __mutable_keys__

          A *note frozenset: 5dd. containing the names of all mutable
          keys.  Keys are mutable if they do not carry the *note
          ReadOnly: 161. qualifier.

          Added in version 3.13.

     See PEP 589(3) for more examples and detailed rules of using
     ‘TypedDict’.

     Added in version 3.8.

     Changed in version 3.9: ‘TypedDict’ is now a function rather than a
     class.  It can still be used as a class base, as described above.

     Changed in version 3.11: Added support for marking individual keys
     as *note Required: 5c7. or *note NotRequired: 5c8.  See PEP 655(4).

     Changed in version 3.11: Added support for generic ‘TypedDict’s.

     Changed in version 3.13: Removed support for the keyword-argument
     method of creating ‘TypedDict’s.

     Changed in version 3.13: Support for the *note ReadOnly: 161.
     qualifier was added.

     Deprecated since version 3.13, will be removed in version 3.15:
     When using the functional syntax to create a TypedDict class,
     failing to pass a value to the ‘fields’ parameter (‘TD =
     TypedDict("TD")’) is deprecated.  Passing ‘None’ to the ‘fields’
     parameter (‘TD = TypedDict("TD", None)’) is also deprecated.  Both
     will be disallowed in Python 3.15.  To create a TypedDict class
     with 0 fields, use ‘class TD(TypedDict): pass’ or ‘TD =
     TypedDict("TD", {})’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0526/

   (2) https://peps.python.org/pep-0544/

   (3) https://peps.python.org/pep-0589/

   (4) https://peps.python.org/pep-0655/


File: python.info,  Node: Protocols<3>,  Next: ABCs for working with IO,  Prev: Special typing primitives,  Up: Module contents<4>

5.26.1.18 Protocols
...................

The following protocols are provided by the ‘typing’ module.  All are
decorated with *note @runtime_checkable: 446.

 -- Class: typing.SupportsAbs

     An ABC with one abstract method ‘__abs__’ that is covariant in its
     return type.

 -- Class: typing.SupportsBytes

     An ABC with one abstract method ‘__bytes__’.

 -- Class: typing.SupportsComplex

     An ABC with one abstract method ‘__complex__’.

 -- Class: typing.SupportsFloat

     An ABC with one abstract method ‘__float__’.

 -- Class: typing.SupportsIndex

     An ABC with one abstract method ‘__index__’.

     Added in version 3.8.

 -- Class: typing.SupportsInt

     An ABC with one abstract method ‘__int__’.

 -- Class: typing.SupportsRound

     An ABC with one abstract method ‘__round__’ that is covariant in
     its return type.


File: python.info,  Node: ABCs for working with IO,  Next: Functions and decorators,  Prev: Protocols<3>,  Up: Module contents<4>

5.26.1.19 ABCs for working with IO
..................................

 -- Class: typing.IO
 -- Class: typing.TextIO
 -- Class: typing.BinaryIO

     Generic type ‘IO[AnyStr]’ and its subclasses ‘TextIO(IO[str])’ and
     ‘BinaryIO(IO[bytes])’ represent the types of I/O streams such as
     returned by *note open(): 51f.


File: python.info,  Node: Functions and decorators,  Next: Introspection helpers,  Prev: ABCs for working with IO,  Up: Module contents<4>

5.26.1.20 Functions and decorators
..................................

 -- Function: typing.cast (typ, val)

     Cast a value to a type.

     This returns the value unchanged.  To the type checker this signals
     that the return value has the designated type, but at runtime we
     intentionally don’t check anything (we want this to be as fast as
     possible).

 -- Function: typing.assert_type (val, typ, /)

     Ask a static type checker to confirm that 'val' has an inferred
     type of 'typ'.

     At runtime this does nothing: it returns the first argument
     unchanged with no checks or side effects, no matter the actual type
     of the argument.

     When a static type checker encounters a call to ‘assert_type()’, it
     emits an error if the value is not of the specified type:

          def greet(name: str) -> None:
              assert_type(name, str)  # OK, inferred type of `name` is `str`
              assert_type(name, int)  # type checker error

     This function is useful for ensuring the type checker’s
     understanding of a script is in line with the developer’s
     intentions:

          def complex_function(arg: object):
              # Do some complex type-narrowing logic,
              # after which we hope the inferred type will be `int`
              ...
              # Test whether the type checker correctly understands our function
              assert_type(arg, int)

     Added in version 3.11.

 -- Function: typing.assert_never (arg, /)

     Ask a static type checker to confirm that a line of code is
     unreachable.

     Example:

          def int_or_str(arg: int | str) -> None:
              match arg:
                  case int():
                      print("It's an int")
                  case str():
                      print("It's a str")
                  case _ as unreachable:
                      assert_never(unreachable)

     Here, the annotations allow the type checker to infer that the last
     case can never execute, because ‘arg’ is either an *note int: 257.
     or a *note str: 44f, and both options are covered by earlier cases.

     If a type checker finds that a call to ‘assert_never()’ is
     reachable, it will emit an error.  For example, if the type
     annotation for ‘arg’ was instead ‘int | str | float’, the type
     checker would emit an error pointing out that ‘unreachable’ is of
     type *note float: 2f7.  For a call to ‘assert_never’ to pass type
     checking, the inferred type of the argument passed in must be the
     bottom type, *note Never: 6ab, and nothing else.

     At runtime, this throws an exception when called.

     See also
     ........

     Unreachable Code and Exhaustiveness Checking(1) has more
     information about exhaustiveness checking with static typing.

     Added in version 3.11.

 -- Function: typing.reveal_type (obj, /)

     Ask a static type checker to reveal the inferred type of an
     expression.

     When a static type checker encounters a call to this function, it
     emits a diagnostic with the inferred type of the argument.  For
     example:

          x: int = 1
          reveal_type(x)  # Revealed type is "builtins.int"

     This can be useful when you want to debug how your type checker
     handles a particular piece of code.

     At runtime, this function prints the runtime type of its argument
     to *note sys.stderr: 943. and returns the argument unchanged
     (allowing the call to be used within an expression):

          x = reveal_type(1)  # prints "Runtime type is int"
          print(x)  # prints "1"

     Note that the runtime type may be different from (more or less
     specific than) the type statically inferred by a type checker.

     Most type checkers support ‘reveal_type()’ anywhere, even if the
     name is not imported from ‘typing’.  Importing the name from
     ‘typing’, however, allows your code to run without runtime errors
     and communicates intent more clearly.

     Added in version 3.11.

 -- Function: @typing.dataclass_transform (*, eq_default=True,
          order_default=False, kw_only_default=False,
          frozen_default=False, field_specifiers=(), **kwargs)

     Decorator to mark an object as providing *note dataclass: 1cb.-like
     behavior.

     ‘dataclass_transform’ may be used to decorate a class, metaclass,
     or a function that is itself a decorator.  The presence of
     ‘@dataclass_transform()’ tells a static type checker that the
     decorated object performs runtime “magic” that transforms a class
     in a similar way to *note @dataclasses.dataclass: 1cb.

     Example usage with a decorator function:

          @dataclass_transform()
          def create_model[T](cls: type[T]) -> type[T]:
              ...
              return cls

          @create_model
          class CustomerModel:
              id: int
              name: str

     On a base class:

          @dataclass_transform()
          class ModelBase: ...

          class CustomerModel(ModelBase):
              id: int
              name: str

     On a metaclass:

          @dataclass_transform()
          class ModelMeta(type): ...

          class ModelBase(metaclass=ModelMeta): ...

          class CustomerModel(ModelBase):
              id: int
              name: str

     The ‘CustomerModel’ classes defined above will be treated by type
     checkers similarly to classes created with *note
     @dataclasses.dataclass: 1cb.  For example, type checkers will
     assume these classes have ‘__init__’ methods that accept ‘id’ and
     ‘name’.

     The decorated class, metaclass, or function may accept the
     following bool arguments which type checkers will assume have the
     same effect as they would have on the *note @dataclasses.dataclass:
     1cb. decorator: ‘init’, ‘eq’, ‘order’, ‘unsafe_hash’, ‘frozen’,
     ‘match_args’, ‘kw_only’, and ‘slots’.  It must be possible for the
     value of these arguments (‘True’ or ‘False’) to be statically
     evaluated.

     The arguments to the ‘dataclass_transform’ decorator can be used to
     customize the default behaviors of the decorated class, metaclass,
     or function:


     Parameters:

        * ‘eq_default’ (*note bool: 46b.) – Indicates whether the ‘eq’
          parameter is assumed to be ‘True’ or ‘False’ if it is omitted
          by the caller.  Defaults to ‘True’.

        * ‘order_default’ (*note bool: 46b.) – Indicates whether the
          ‘order’ parameter is assumed to be ‘True’ or ‘False’ if it is
          omitted by the caller.  Defaults to ‘False’.

        * ‘kw_only_default’ (*note bool: 46b.) – Indicates whether the
          ‘kw_only’ parameter is assumed to be ‘True’ or ‘False’ if it
          is omitted by the caller.  Defaults to ‘False’.

        * ‘frozen_default’ (*note bool: 46b.) – Indicates whether the
          ‘frozen’ parameter is assumed to be ‘True’ or ‘False’ if it is
          omitted by the caller.  Defaults to ‘False’.

          Added in version 3.12.

        * ‘field_specifiers’ (*note tuple: 373.‘[’*note Callable:
          7ef.‘[’‘...’‘, ’‘Any’‘]’‘, ’‘...’‘]’) – Specifies a static
          list of supported classes or functions that describe fields,
          similar to *note dataclasses.field(): 1bb1.  Defaults to ‘()’.

        * ‘**kwargs’ (‘Any’) – Arbitrary other keyword arguments are
          accepted in order to allow for possible future extensions.

     Type checkers recognize the following optional parameters on field
     specifiers: 'Recognised parameters for field specifiers'

     Parameter name           Description
                              
     --------------------------------------------------------------------------------------------------------------
                              
     ‘init’                   Indicates whether the field should be included in the synthesized ‘__init__’
                              method.  If unspecified, ‘init’ defaults to ‘True’.
                              
                              
     ‘default’                Provides the default value for the field.
                              
                              
     ‘default_factory’        Provides a runtime callback that returns the default value for the field.  If
                              neither ‘default’ nor ‘default_factory’ are specified, the field is assumed to
                              have no default value and must be provided a value when the class is instantiated.
                              
                              
     ‘factory’                An alias for the ‘default_factory’ parameter on field specifiers.
                              
                              
     ‘kw_only’                Indicates whether the field should be marked as keyword-only.  If ‘True’, the
                              field will be keyword-only.  If ‘False’, it will not be keyword-only.  If
                              unspecified, the value of the ‘kw_only’ parameter on the object decorated with
                              ‘dataclass_transform’ will be used, or if that is unspecified, the value of
                              ‘kw_only_default’ on ‘dataclass_transform’ will be used.
                              
                              
     ‘alias’                  Provides an alternative name for the field.  This alternative name is used in the
                              synthesized ‘__init__’ method.
                              

     At runtime, this decorator records its arguments in the
     ‘__dataclass_transform__’ attribute on the decorated object.  It
     has no other runtime effect.

     See PEP 681(2) for more details.

     Added in version 3.11.

 -- Function: @typing.overload

     Decorator for creating overloaded functions and methods.

     The ‘@overload’ decorator allows describing functions and methods
     that support multiple different combinations of argument types.  A
     series of ‘@overload’-decorated definitions must be followed by
     exactly one non-‘@overload’-decorated definition (for the same
     function/method).

     ‘@overload’-decorated definitions are for the benefit of the type
     checker only, since they will be overwritten by the
     non-‘@overload’-decorated definition.  The
     non-‘@overload’-decorated definition, meanwhile, will be used at
     runtime but should be ignored by a type checker.  At runtime,
     calling an ‘@overload’-decorated function directly will raise *note
     NotImplementedError: 228.

     An example of overload that gives a more precise type than can be
     expressed using a union or a type variable:

          @overload
          def process(response: None) -> None:
              ...
          @overload
          def process(response: int) -> tuple[int, str]:
              ...
          @overload
          def process(response: bytes) -> str:
              ...
          def process(response):
              ...  # actual implementation goes here

     See PEP 484(3) for more details and comparison with other typing
     semantics.

     Changed in version 3.11: Overloaded functions can now be
     introspected at runtime using *note get_overloads(): 6b1.

 -- Function: typing.get_overloads (func)

     Return a sequence of *note @overload: 41e8.-decorated definitions
     for 'func'.

     'func' is the function object for the implementation of the
     overloaded function.  For example, given the definition of
     ‘process’ in the documentation for *note @overload: 41e8,
     ‘get_overloads(process)’ will return a sequence of three function
     objects for the three defined overloads.  If called on a function
     with no overloads, ‘get_overloads()’ returns an empty sequence.

     ‘get_overloads()’ can be used for introspecting an overloaded
     function at runtime.

     Added in version 3.11.

 -- Function: typing.clear_overloads ()

     Clear all registered overloads in the internal registry.

     This can be used to reclaim the memory used by the registry.

     Added in version 3.11.

 -- Function: @typing.final

     Decorator to indicate final methods and final classes.

     Decorating a method with ‘@final’ indicates to a type checker that
     the method cannot be overridden in a subclass.  Decorating a class
     with ‘@final’ indicates that it cannot be subclassed.

     For example:

          class Base:
              @final
              def done(self) -> None:
                  ...
          class Sub(Base):
              def done(self) -> None:  # Error reported by type checker
                  ...

          @final
          class Leaf:
              ...
          class Other(Leaf):  # Error reported by type checker
              ...

     There is no runtime checking of these properties.  See PEP 591(4)
     for more details.

     Added in version 3.8.

     Changed in version 3.11: The decorator will now attempt to set a
     ‘__final__’ attribute to ‘True’ on the decorated object.  Thus, a
     check like ‘if getattr(obj, "__final__", False)’ can be used at
     runtime to determine whether an object ‘obj’ has been marked as
     final.  If the decorated object does not support setting
     attributes, the decorator returns the object unchanged without
     raising an exception.

 -- Function: @typing.no_type_check

     Decorator to indicate that annotations are not type hints.

     This works as a class or function *note decorator: 734.  With a
     class, it applies recursively to all methods and classes defined in
     that class (but not to methods defined in its superclasses or
     subclasses).  Type checkers will ignore all annotations in a
     function or class with this decorator.

     ‘@no_type_check’ mutates the decorated object in place.

 -- Function: @typing.no_type_check_decorator

     Decorator to give another decorator the *note no_type_check(): 6b7.
     effect.

     This wraps the decorator with something that wraps the decorated
     function in *note no_type_check(): 6b7.

     Deprecated since version 3.13, will be removed in version 3.15: No
     type checker ever added support for ‘@no_type_check_decorator’.  It
     is therefore deprecated, and will be removed in Python 3.15.

 -- Function: @typing.override

     Decorator to indicate that a method in a subclass is intended to
     override a method or attribute in a superclass.

     Type checkers should emit an error if a method decorated with
     ‘@override’ does not, in fact, override anything.  This helps
     prevent bugs that may occur when a base class is changed without an
     equivalent change to a child class.

     For example:

          class Base:
              def log_status(self) -> None:
                  ...

          class Sub(Base):
              @override
              def log_status(self) -> None:  # Okay: overrides Base.log_status
                  ...

              @override
              def done(self) -> None:  # Error reported by type checker
                  ...

     There is no runtime checking of this property.

     The decorator will attempt to set an ‘__override__’ attribute to
     ‘True’ on the decorated object.  Thus, a check like ‘if
     getattr(obj, "__override__", False)’ can be used at runtime to
     determine whether an object ‘obj’ has been marked as an override.
     If the decorated object does not support setting attributes, the
     decorator returns the object unchanged without raising an
     exception.

     See PEP 698(5) for more details.

     Added in version 3.12.

 -- Function: @typing.type_check_only

     Decorator to mark a class or function as unavailable at runtime.

     This decorator is itself not available at runtime.  It is mainly
     intended to mark classes that are defined in type stub files if an
     implementation returns an instance of a private class:

          @type_check_only
          class Response:  # private or not available at runtime
              code: int
              def get_header(self, name: str) -> str: ...

          def fetch_response() -> Response: ...

     Note that returning instances of private classes is not
     recommended.  It is usually preferable to make such classes public.

   ---------- Footnotes ----------

   (1) https://typing.python.org/en/latest/guides/unreachable.html

   (2) https://peps.python.org/pep-0681/

   (3) https://peps.python.org/pep-0484/

   (4) https://peps.python.org/pep-0591/

   (5) https://peps.python.org/pep-0698/


File: python.info,  Node: Introspection helpers,  Next: Constant,  Prev: Functions and decorators,  Up: Module contents<4>

5.26.1.21 Introspection helpers
...............................

 -- Function: typing.get_type_hints (obj, globalns=None, localns=None,
          include_extras=False)

     Return a dictionary containing type hints for a function, method,
     module or class object.

     This is often the same as ‘obj.__annotations__’, but this function
     makes the following changes to the annotations dictionary:

        * Forward references encoded as string literals or *note
          ForwardRef: 197f. objects are handled by evaluating them in
          'globalns', 'localns', and (where applicable) 'obj'’s *note
          type parameter: 2b3. namespace.  If 'globalns' or 'localns' is
          not given, appropriate namespace dictionaries are inferred
          from 'obj'.

        * ‘None’ is replaced with *note types.NoneType: 858.

        * If *note @no_type_check: 6b7. has been applied to 'obj', an
          empty dictionary is returned.

        * If 'obj' is a class ‘C’, the function returns a dictionary
          that merges annotations from ‘C’’s base classes with those on
          ‘C’ directly.  This is done by traversing *note C.__mro__:
          20da. and iteratively combining ‘__annotations__’
          dictionaries.  Annotations on classes appearing earlier in the
          *note method resolution order: 2339. always take precedence
          over annotations on classes appearing later in the method
          resolution order.

        * The function recursively replaces all occurrences of
          ‘Annotated[T, ...]’, ‘Required[T]’, ‘NotRequired[T]’, and
          ‘ReadOnly[T]’ with ‘T’, unless 'include_extras' is set to
          ‘True’ (see *note Annotated: 947. for more information).

     See also *note inspect.get_annotations(): 819, a lower-level
     function that returns annotations more directly.

          Note: If any forward references in the annotations of 'obj'
          are not resolvable or are not valid Python code, this function
          will raise an exception such as *note NameError: 442.  For
          example, this can happen with imported *note type aliases:
          457. that include forward references, or with names imported
          under *note if TYPE_CHECKING: d1b.

     Changed in version 3.9: Added ‘include_extras’ parameter as part of
     PEP 593(1).  See the documentation on *note Annotated: 947. for
     more information.

     Changed in version 3.11: Previously, ‘Optional[t]’ was added for
     function and method annotations if a default value equal to ‘None’
     was set.  Now the annotation is returned unchanged.

 -- Function: typing.get_origin (tp)

     Get the unsubscripted version of a type: for a typing object of the
     form ‘X[Y, Z, ...]’ return ‘X’.

     If ‘X’ is a typing-module alias for a builtin or *note collections:
     1d. class, it will be normalized to the original class.  If ‘X’ is
     an instance of *note ParamSpecArgs: 7ca. or *note ParamSpecKwargs:
     7cb, return the underlying *note ParamSpec: 15e.  Return ‘None’ for
     unsupported objects.

     Examples:

          assert get_origin(str) is None
          assert get_origin(Dict[str, int]) is dict
          assert get_origin(Union[int, str]) is Union
          assert get_origin(Annotated[str, "metadata"]) is Annotated
          P = ParamSpec('P')
          assert get_origin(P.args) is P
          assert get_origin(P.kwargs) is P

     Added in version 3.8.

 -- Function: typing.get_args (tp)

     Get type arguments with all substitutions performed: for a typing
     object of the form ‘X[Y, Z, ...]’ return ‘(Y, Z, ...)’.

     If ‘X’ is a union or *note Literal: 85b. contained in another
     generic type, the order of ‘(Y, Z, ...)’ may be different from the
     order of the original arguments ‘[Y, Z, ...]’ due to type caching.
     Return ‘()’ for unsupported objects.

     Examples:

          assert get_args(int) == ()
          assert get_args(Dict[int, str]) == (int, str)
          assert get_args(Union[int, str]) == (int, str)

     Added in version 3.8.

 -- Function: typing.get_protocol_members (tp)

     Return the set of members defined in a *note Protocol: 264.

          >>> from typing import Protocol, get_protocol_members
          >>> class P(Protocol):
          ...     def a(self) -> str: ...
          ...     b: int
          >>> get_protocol_members(P) == frozenset({'a', 'b'})
          True

     Raise *note TypeError: 2c3. for arguments that are not Protocols.

     Added in version 3.13.

 -- Function: typing.is_protocol (tp)

     Determine if a type is a *note Protocol: 264.

     For example:

          class P(Protocol):
              def a(self) -> str: ...
              b: int

          is_protocol(P)    # => True
          is_protocol(int)  # => False

     Added in version 3.13.

 -- Function: typing.is_typeddict (tp)

     Check if a type is a *note TypedDict: 162.

     For example:

          class Film(TypedDict):
              title: str
              year: int

          assert is_typeddict(Film)
          assert not is_typeddict(list | str)

          # TypedDict is a factory for creating typed dicts,
          # not a typed dict itself
          assert not is_typeddict(TypedDict)

     Added in version 3.10.

 -- Class: typing.ForwardRef

     Class used for internal typing representation of string forward
     references.

     For example, ‘List["SomeClass"]’ is implicitly transformed into
     ‘List[ForwardRef("SomeClass")]’.  ‘ForwardRef’ should not be
     instantiated by a user, but may be used by introspection tools.

          Note: PEP 585(2) generic types such as ‘list["SomeClass"]’
          will not be implicitly transformed into
          ‘list[ForwardRef("SomeClass")]’ and thus will not
          automatically resolve to ‘list[SomeClass]’.

     Added in version 3.7.4.

 -- Data: typing.NoDefault

     A sentinel object used to indicate that a type parameter has no
     default value.  For example:

          >>> T = TypeVar("T")
          >>> T.__default__ is typing.NoDefault
          True
          >>> S = TypeVar("S", default=None)
          >>> S.__default__ is None
          True

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0593/

   (2) https://peps.python.org/pep-0585/


File: python.info,  Node: Constant,  Next: Deprecated aliases,  Prev: Introspection helpers,  Up: Module contents<4>

5.26.1.22 Constant
..................

 -- Data: typing.TYPE_CHECKING

     A special constant that is assumed to be ‘True’ by 3rd party static
     type checkers.  It is ‘False’ at runtime.

     Usage:

          if TYPE_CHECKING:
              import expensive_mod

          def fun(arg: 'expensive_mod.SomeType') -> None:
              local_var: expensive_mod.AnotherType = other_fun()

     The first type annotation must be enclosed in quotes, making it a
     “forward reference”, to hide the ‘expensive_mod’ reference from the
     interpreter runtime.  Type annotations for local variables are not
     evaluated, so the second annotation does not need to be enclosed in
     quotes.

          Note: If ‘from __future__ import annotations’ is used,
          annotations are not evaluated at function definition time.
          Instead, they are stored as strings in ‘__annotations__’.
          This makes it unnecessary to use quotes around the annotation
          (see PEP 563(1)).

     Added in version 3.5.2.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0563/


File: python.info,  Node: Deprecated aliases,  Prev: Constant,  Up: Module contents<4>

5.26.1.23 Deprecated aliases
............................

This module defines several deprecated aliases to pre-existing standard
library classes.  These were originally included in the ‘typing’ module
in order to support parameterizing these generic classes using ‘[]’.
However, the aliases became redundant in Python 3.9 when the
corresponding pre-existing classes were enhanced to support ‘[]’ (see
PEP 585(1)).

The redundant types are deprecated as of Python 3.9.  However, while the
aliases may be removed at some point, removal of these aliases is not
currently planned.  As such, no deprecation warnings are currently
issued by the interpreter for these aliases.

If at some point it is decided to remove these deprecated aliases, a
deprecation warning will be issued by the interpreter for at least two
releases prior to removal.  The aliases are guaranteed to remain in the
‘typing’ module without deprecation warnings until at least Python 3.14.

Type checkers are encouraged to flag uses of the deprecated types if the
program they are checking targets a minimum Python version of 3.9 or
newer.

* Menu:

* Aliases to built-in types::
* Aliases to types in collections::
* Aliases to other concrete types::
* Aliases to container ABCs in collections.abc: Aliases to container ABCs in collections abc.
* Aliases to asynchronous ABCs in collections.abc: Aliases to asynchronous ABCs in collections abc.
* Aliases to other ABCs in collections.abc: Aliases to other ABCs in collections abc.
* Aliases to contextlib ABCs::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to built-in types,  Next: Aliases to types in collections,  Up: Deprecated aliases

5.26.1.24 Aliases to built-in types
...................................

 -- Class: typing.Dict (dict, MutableMapping[KT, VT])

     Deprecated alias to *note dict: 256.

     Note that to annotate arguments, it is preferred to use an abstract
     collection type such as *note Mapping: 8d3. rather than to use
     *note dict: 256. or ‘typing.Dict’.

     Deprecated since version 3.9: *note builtins.dict: 256. now
     supports subscripting (‘[]’).  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.List (list, MutableSequence[T])

     Deprecated alias to *note list: 614.

     Note that to annotate arguments, it is preferred to use an abstract
     collection type such as *note Sequence: 1209. or *note Iterable:
     2405. rather than to use *note list: 614. or ‘typing.List’.

     Deprecated since version 3.9: *note builtins.list: 614. now
     supports subscripting (‘[]’).  See PEP 585(2) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Set (set, MutableSet[T])

     Deprecated alias to *note builtins.set: 5dc.

     Note that to annotate arguments, it is preferred to use an abstract
     collection type such as *note collections.abc.Set: 23fd. rather
     than to use *note set: 5dc. or *note typing.Set: 41f3.

     Deprecated since version 3.9: *note builtins.set: 5dc. now supports
     subscripting (‘[]’).  See PEP 585(3) and *note Generic Alias Type:
     6b5.

 -- Class: typing.FrozenSet (frozenset, AbstractSet[T_co])

     Deprecated alias to *note builtins.frozenset: 5dd.

     Deprecated since version 3.9: *note builtins.frozenset: 5dd. now
     supports subscripting (‘[]’).  See PEP 585(4) and *note Generic
     Alias Type: 6b5.

 -- Data: typing.Tuple

     Deprecated alias for *note tuple: 373.

     *note tuple: 373. and ‘Tuple’ are special-cased in the type system;
     see *note Annotating tuples: 2428. for more details.

     Deprecated since version 3.9: *note builtins.tuple: 373. now
     supports subscripting (‘[]’).  See PEP 585(5) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Type (Generic[CT_co])

     Deprecated alias to *note type: d71.

     See *note The type of class objects: 41b3. for details on using
     *note type: d71. or ‘typing.Type’ in type annotations.

     Added in version 3.5.2.

     Deprecated since version 3.9: *note builtins.type: d71. now
     supports subscripting (‘[]’).  See PEP 585(6) and *note Generic
     Alias Type: 6b5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0585/

   (3) https://peps.python.org/pep-0585/

   (4) https://peps.python.org/pep-0585/

   (5) https://peps.python.org/pep-0585/

   (6) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to types in collections,  Next: Aliases to other concrete types,  Prev: Aliases to built-in types,  Up: Deprecated aliases

5.26.1.25 Aliases to types in ‘collections’
...........................................

 -- Class: typing.DefaultDict (collections.defaultdict,
          MutableMapping[KT, VT])

     Deprecated alias to *note collections.defaultdict: 1201.

     Added in version 3.5.2.

     Deprecated since version 3.9: *note collections.defaultdict: 1201.
     now supports subscripting (‘[]’).  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.OrderedDict (collections.OrderedDict,
          MutableMapping[KT, VT])

     Deprecated alias to *note collections.OrderedDict: 5de.

     Added in version 3.7.2.

     Deprecated since version 3.9: *note collections.OrderedDict: 5de.
     now supports subscripting (‘[]’).  See PEP 585(2) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.ChainMap (collections.ChainMap, MutableMapping[KT,
          VT])

     Deprecated alias to *note collections.ChainMap: c3c.

     Added in version 3.6.1.

     Deprecated since version 3.9: *note collections.ChainMap: c3c. now
     supports subscripting (‘[]’).  See PEP 585(3) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Counter (collections.Counter, Dict[T, int])

     Deprecated alias to *note collections.Counter: 10d5.

     Added in version 3.6.1.

     Deprecated since version 3.9: *note collections.Counter: 10d5. now
     supports subscripting (‘[]’).  See PEP 585(4) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Deque (deque, MutableSequence[T])

     Deprecated alias to *note collections.deque: 5df.

     Added in version 3.6.1.

     Deprecated since version 3.9: *note collections.deque: 5df. now
     supports subscripting (‘[]’).  See PEP 585(5) and *note Generic
     Alias Type: 6b5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0585/

   (3) https://peps.python.org/pep-0585/

   (4) https://peps.python.org/pep-0585/

   (5) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to other concrete types,  Next: Aliases to container ABCs in collections abc,  Prev: Aliases to types in collections,  Up: Deprecated aliases

5.26.1.26 Aliases to other concrete types
.........................................

 -- Class: typing.Pattern
 -- Class: typing.Match

     Deprecated aliases corresponding to the return types from *note
     re.compile(): bf4. and *note re.match(): 1273.

     These types (and the corresponding functions) are generic over
     *note AnyStr: 2b2.  ‘Pattern’ can be specialised as ‘Pattern[str]’
     or ‘Pattern[bytes]’; ‘Match’ can be specialised as ‘Match[str]’ or
     ‘Match[bytes]’.

     Deprecated since version 3.9: Classes ‘Pattern’ and ‘Match’ from
     *note re: b9. now support ‘[]’.  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Text

     Deprecated alias for *note str: 44f.

     ‘Text’ is provided to supply a forward compatible path for Python 2
     code: in Python 2, ‘Text’ is an alias for ‘unicode’.

     Use ‘Text’ to indicate that a value must contain a unicode string
     in a manner that is compatible with both Python 2 and Python 3:

          def add_unicode_checkmark(text: Text) -> Text:
              return text + u' \u2713'

     Added in version 3.5.2.

     Deprecated since version 3.11: Python 2 is no longer supported, and
     most type checkers also no longer support type checking Python 2
     code.  Removal of the alias is not currently planned, but users are
     encouraged to use *note str: 44f. instead of ‘Text’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to container ABCs in collections abc,  Next: Aliases to asynchronous ABCs in collections abc,  Prev: Aliases to other concrete types,  Up: Deprecated aliases

5.26.1.27 Aliases to container ABCs in ‘collections.abc’
........................................................

 -- Class: typing.AbstractSet (Collection[T_co])

     Deprecated alias to *note collections.abc.Set: 23fd.

     Deprecated since version 3.9: *note collections.abc.Set: 23fd. now
     supports subscripting (‘[]’).  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.ByteString (Sequence[int])

     Deprecated alias to *note collections.abc.ByteString: 2e7.

     Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
     implements the *note buffer protocol: 2e8. at runtime.  For use in
     type annotations, either use *note Buffer: 2e9. or a union that
     explicitly specifies the types your code supports (e.g., ‘bytes |
     bytearray | memoryview’).

     ‘ByteString’ was originally intended to be an abstract class that
     would serve as a supertype of both *note bytes: 1c2. and *note
     bytearray: 2ea.  However, since the ABC never had any methods,
     knowing that an object was an instance of ‘ByteString’ never
     actually told you anything useful about the object.  Other common
     buffer types such as *note memoryview: 2eb. were also never
     understood as subtypes of ‘ByteString’ (either at runtime or by
     static type checkers).

     See PEP 688(2) for more details.

     Deprecated since version 3.9, will be removed in version 3.17.

 -- Class: typing.Collection (Sized, Iterable[T_co], Container[T_co])

     Deprecated alias to *note collections.abc.Collection: cab.

     Added in version 3.6.

     Deprecated since version 3.9: *note collections.abc.Collection:
     cab. now supports subscripting (‘[]’).  See PEP 585(3) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.Container (Generic[T_co])

     Deprecated alias to *note collections.abc.Container: 2407.

     Deprecated since version 3.9: *note collections.abc.Container:
     2407. now supports subscripting (‘[]’).  See PEP 585(4) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.ItemsView (MappingView, AbstractSet[tuple[KT_co,
          VT_co]])

     Deprecated alias to *note collections.abc.ItemsView: 240b.

     Deprecated since version 3.9: *note collections.abc.ItemsView:
     240b. now supports subscripting (‘[]’).  See PEP 585(5) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.KeysView (MappingView, AbstractSet[KT_co])

     Deprecated alias to *note collections.abc.KeysView: 240a.

     Deprecated since version 3.9: *note collections.abc.KeysView: 240a.
     now supports subscripting (‘[]’).  See PEP 585(6) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Mapping (Collection[KT], Generic[KT, VT_co])

     Deprecated alias to *note collections.abc.Mapping: 8d3.

     Deprecated since version 3.9: *note collections.abc.Mapping: 8d3.
     now supports subscripting (‘[]’).  See PEP 585(7) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.MappingView (Sized)

     Deprecated alias to *note collections.abc.MappingView: 2409.

     Deprecated since version 3.9: *note collections.abc.MappingView:
     2409. now supports subscripting (‘[]’).  See PEP 585(8) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.MutableMapping (Mapping[KT, VT])

     Deprecated alias to *note collections.abc.MutableMapping: 10f0.

     Deprecated since version 3.9: *note collections.abc.MutableMapping:
     10f0. now supports subscripting (‘[]’).  See PEP 585(9) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.MutableSequence (Sequence[T])

     Deprecated alias to *note collections.abc.MutableSequence: 1a1.

     Deprecated since version 3.9: *note
     collections.abc.MutableSequence: 1a1. now supports subscripting
     (‘[]’).  See PEP 585(10) and *note Generic Alias Type: 6b5.

 -- Class: typing.MutableSet (AbstractSet[T])

     Deprecated alias to *note collections.abc.MutableSet: 2408.

     Deprecated since version 3.9: *note collections.abc.MutableSet:
     2408. now supports subscripting (‘[]’).  See PEP 585(11) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.Sequence (Reversible[T_co], Collection[T_co])

     Deprecated alias to *note collections.abc.Sequence: 1209.

     Deprecated since version 3.9: *note collections.abc.Sequence: 1209.
     now supports subscripting (‘[]’).  See PEP 585(12) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.ValuesView (MappingView, Collection[_VT_co])

     Deprecated alias to *note collections.abc.ValuesView: 240c.

     Deprecated since version 3.9: *note collections.abc.ValuesView:
     240c. now supports subscripting (‘[]’).  See PEP 585(13) and *note
     Generic Alias Type: 6b5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0688/#current-options

   (3) https://peps.python.org/pep-0585/

   (4) https://peps.python.org/pep-0585/

   (5) https://peps.python.org/pep-0585/

   (6) https://peps.python.org/pep-0585/

   (7) https://peps.python.org/pep-0585/

   (8) https://peps.python.org/pep-0585/

   (9) https://peps.python.org/pep-0585/

   (10) https://peps.python.org/pep-0585/

   (11) https://peps.python.org/pep-0585/

   (12) https://peps.python.org/pep-0585/

   (13) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to asynchronous ABCs in collections abc,  Next: Aliases to other ABCs in collections abc,  Prev: Aliases to container ABCs in collections abc,  Up: Deprecated aliases

5.26.1.28 Aliases to asynchronous ABCs in ‘collections.abc’
...........................................................

 -- Class: typing.Coroutine (Awaitable[ReturnType], Generic[YieldType,
          SendType, ReturnType])

     Deprecated alias to *note collections.abc.Coroutine: e0d.

     See *note Annotating generators and coroutines: 26ea. for details
     on using *note collections.abc.Coroutine: e0d. and
     ‘typing.Coroutine’ in type annotations.

     Added in version 3.5.3.

     Deprecated since version 3.9: *note collections.abc.Coroutine: e0d.
     now supports subscripting (‘[]’).  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.AsyncGenerator (AsyncIterator[YieldType],
          Generic[YieldType, SendType])

     Deprecated alias to *note collections.abc.AsyncGenerator: cae.

     See *note Annotating generators and coroutines: 26ea. for details
     on using *note collections.abc.AsyncGenerator: cae. and
     ‘typing.AsyncGenerator’ in type annotations.

     Added in version 3.6.1.

     Deprecated since version 3.9: *note collections.abc.AsyncGenerator:
     cae. now supports subscripting (‘[]’).  See PEP 585(2) and *note
     Generic Alias Type: 6b5.

     Changed in version 3.13: The ‘SendType’ parameter now has a
     default.

 -- Class: typing.AsyncIterable (Generic[T_co])

     Deprecated alias to *note collections.abc.AsyncIterable: e0f.

     Added in version 3.5.2.

     Deprecated since version 3.9: *note collections.abc.AsyncIterable:
     e0f. now supports subscripting (‘[]’).  See PEP 585(3) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.AsyncIterator (AsyncIterable[T_co])

     Deprecated alias to *note collections.abc.AsyncIterator: e0e.

     Added in version 3.5.2.

     Deprecated since version 3.9: *note collections.abc.AsyncIterator:
     e0e. now supports subscripting (‘[]’).  See PEP 585(4) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.Awaitable (Generic[T_co])

     Deprecated alias to *note collections.abc.Awaitable: e0c.

     Added in version 3.5.2.

     Deprecated since version 3.9: *note collections.abc.Awaitable: e0c.
     now supports subscripting (‘[]’).  See PEP 585(5) and *note Generic
     Alias Type: 6b5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0585/

   (3) https://peps.python.org/pep-0585/

   (4) https://peps.python.org/pep-0585/

   (5) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to other ABCs in collections abc,  Next: Aliases to contextlib ABCs,  Prev: Aliases to asynchronous ABCs in collections abc,  Up: Deprecated aliases

5.26.1.29 Aliases to other ABCs in ‘collections.abc’
....................................................

 -- Class: typing.Iterable (Generic[T_co])

     Deprecated alias to *note collections.abc.Iterable: 2405.

     Deprecated since version 3.9: *note collections.abc.Iterable: 2405.
     now supports subscripting (‘[]’).  See PEP 585(1) and *note Generic
     Alias Type: 6b5.

 -- Class: typing.Iterator (Iterable[T_co])

     Deprecated alias to *note collections.abc.Iterator: 2406.

     Deprecated since version 3.9: *note collections.abc.Iterator: 2406.
     now supports subscripting (‘[]’).  See PEP 585(2) and *note Generic
     Alias Type: 6b5.

 -- Data: typing.Callable

     Deprecated alias to *note collections.abc.Callable: 7ef.

     See *note Annotating callable objects: 2427. for details on how to
     use *note collections.abc.Callable: 7ef. and ‘typing.Callable’ in
     type annotations.

     Deprecated since version 3.9: *note collections.abc.Callable: 7ef.
     now supports subscripting (‘[]’).  See PEP 585(3) and *note Generic
     Alias Type: 6b5.

     Changed in version 3.10: ‘Callable’ now supports *note ParamSpec:
     15e. and *note Concatenate: 7c8.  See PEP 612(4) for more details.

 -- Class: typing.Generator (Iterator[YieldType], Generic[YieldType,
          SendType, ReturnType])

     Deprecated alias to *note collections.abc.Generator: e0b.

     See *note Annotating generators and coroutines: 26ea. for details
     on using *note collections.abc.Generator: e0b. and
     ‘typing.Generator’ in type annotations.

     Deprecated since version 3.9: *note collections.abc.Generator: e0b.
     now supports subscripting (‘[]’).  See PEP 585(5) and *note Generic
     Alias Type: 6b5.

     Changed in version 3.13: Default values for the send and return
     types were added.

 -- Class: typing.Hashable

     Deprecated alias to *note collections.abc.Hashable: 4f8.

     Deprecated since version 3.12: Use *note collections.abc.Hashable:
     4f8. directly instead.

 -- Class: typing.Reversible (Iterable[T_co])

     Deprecated alias to *note collections.abc.Reversible: cac.

     Deprecated since version 3.9: *note collections.abc.Reversible:
     cac. now supports subscripting (‘[]’).  See PEP 585(6) and *note
     Generic Alias Type: 6b5.

 -- Class: typing.Sized

     Deprecated alias to *note collections.abc.Sized: 4f9.

     Deprecated since version 3.12: Use *note collections.abc.Sized:
     4f9. directly instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0585/

   (3) https://peps.python.org/pep-0585/

   (4) https://peps.python.org/pep-0612/

   (5) https://peps.python.org/pep-0585/

   (6) https://peps.python.org/pep-0585/


File: python.info,  Node: Aliases to contextlib ABCs,  Prev: Aliases to other ABCs in collections abc,  Up: Deprecated aliases

5.26.1.30 Aliases to ‘contextlib’ ABCs
......................................

 -- Class: typing.ContextManager (Generic[T_co, ExitT_co])

     Deprecated alias to *note contextlib.AbstractContextManager: cb1.

     The first type parameter, ‘T_co’, represents the type returned by
     the *note __enter__(): 5cb. method.  The optional second type
     parameter, ‘ExitT_co’, which defaults to ‘bool | None’, represents
     the type returned by the *note __exit__(): 1349. method.

     Added in version 3.5.4.

     Deprecated since version 3.9: *note
     contextlib.AbstractContextManager: cb1. now supports subscripting
     (‘[]’).  See PEP 585(1) and *note Generic Alias Type: 6b5.

     Changed in version 3.13: Added the optional second type parameter,
     ‘ExitT_co’.

 -- Class: typing.AsyncContextManager (Generic[T_co, AExitT_co])

     Deprecated alias to *note contextlib.AbstractAsyncContextManager:
     b43.

     The first type parameter, ‘T_co’, represents the type returned by
     the *note __aenter__(): 2181. method.  The optional second type
     parameter, ‘AExitT_co’, which defaults to ‘bool | None’, represents
     the type returned by the *note __aexit__(): 1734. method.

     Added in version 3.6.2.

     Deprecated since version 3.9: *note
     contextlib.AbstractAsyncContextManager: b43. now supports
     subscripting (‘[]’).  See PEP 585(2) and *note Generic Alias Type:
     6b5.

     Changed in version 3.13: Added the optional second type parameter,
     ‘AExitT_co’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://peps.python.org/pep-0585/


File: python.info,  Node: Deprecation Timeline of Major Features,  Prev: Module contents<4>,  Up: typing — Support for type hints

5.26.1.31 Deprecation Timeline of Major Features
................................................

Certain features in ‘typing’ are deprecated and may be removed in a
future version of Python.  The following table summarizes major
deprecations for your convenience.  This is subject to change, and not
all deprecations are listed.

Feature                       Deprecated in                 Projected removal             PEP/issue
                                                                                          
------------------------------------------------------------------------------------------------------------------------
                                                                                          
‘typing’ versions of          3.9                           Undecided (see                PEP 585(1)
standard collections                                        *note Deprecated aliases: 41ed.
                                                            for more information)
                                                            
                                                                                          
*note typing.ByteString: 2ee. 3.9                           3.17                          gh-91896(2)
                                                                                          
                                                                                          
*note typing.Text: 30b.       3.11                          Undecided                     gh-92332(3)
                                                                                          
                                                                                          
*note typing.Hashable: 4f6.   3.12                          Undecided                     gh-94309(4)
and                                                                                       
*note typing.Sized: 4f7.

*note typing.TypeAlias: 7cd.  3.12                          Undecided                     PEP 695(5)
                                                                                          
                                                                                          
*note @typing.no_type_check_decorator: 2b1.3.13             3.15                          gh-106309(6)
                                                                                          
                                                                                          
*note typing.AnyStr: 2b2.     3.13                          3.18                          gh-105578(7)
                                                                                          

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0585/

   (2) https://github.com/python/cpython/issues/91896

   (3) https://github.com/python/cpython/issues/92332

   (4) https://github.com/python/cpython/issues/94309

   (5) https://peps.python.org/pep-0695/

   (6) https://github.com/python/cpython/issues/106309

   (7) https://github.com/python/cpython/issues/105578


File: python.info,  Node: pydoc — Documentation generator and online help system,  Next: Python Development Mode,  Prev: typing — Support for type hints,  Up: Development Tools

5.26.2 ‘pydoc’ — Documentation generator and online help system
---------------------------------------------------------------

'Source code:' Lib/pydoc.py(1)

__________________________________________________________________

The ‘pydoc’ module automatically generates documentation from Python
modules.  The documentation can be presented as pages of text on the
console, served to a web browser, or saved to HTML files.

For modules, classes, functions and methods, the displayed documentation
is derived from the docstring (i.e.  the *note __doc__: 931. attribute)
of the object, and recursively of its documentable members.  If there is
no docstring, ‘pydoc’ tries to obtain a description from the block of
comment lines just above the definition of the class, function or method
in the source file, or at the top of the module (see *note
inspect.getcomments(): 16ce.).

The built-in function *note help(): 8e0. invokes the online help system
in the interactive interpreter, which uses ‘pydoc’ to generate its
documentation as text on the console.  The same text documentation can
also be viewed from outside the Python interpreter by running ‘pydoc’ as
a script at the operating system’s command prompt.  For example, running

     python -m pydoc sys

at a shell prompt will display documentation on the *note sys: d9.
module, in a style similar to the manual pages shown by the Unix ‘man’
command.  The argument to ‘pydoc’ can be the name of a function, module,
or package, or a dotted reference to a class, method, or function within
a module or module in a package.  If the argument to ‘pydoc’ looks like
a path (that is, it contains the path separator for your operating
system, such as a slash in Unix), and refers to an existing Python
source file, then documentation is produced for that file.

     Note: In order to find objects and their documentation, ‘pydoc’
     imports the module(s) to be documented.  Therefore, any code on
     module level will be executed on that occasion.  Use an ‘if
     __name__ == '__main__':’ guard to only execute code when a file is
     invoked as a script and not just imported.

When printing output to the console, ‘pydoc’ attempts to paginate the
output for easier reading.  If either the ‘MANPAGER’ or the ‘PAGER’
environment variable is set, ‘pydoc’ will use its value as a pagination
program.  When both are set, ‘MANPAGER’ is used.

Specifying a ‘-w’ flag before the argument will cause HTML documentation
to be written out to a file in the current directory, instead of
displaying text on the console.

Specifying a ‘-k’ flag before the argument will search the synopsis
lines of all available modules for the keyword given as the argument,
again in a manner similar to the Unix ‘man’ command.  The synopsis line
of a module is the first line of its documentation string.

You can also use ‘pydoc’ to start an HTTP server on the local machine
that will serve documentation to visiting web browsers.  ‘python -m
pydoc -p 1234’ will start a HTTP server on port 1234, allowing you to
browse the documentation at ‘http://localhost:1234/’ in your preferred
web browser.  Specifying ‘0’ as the port number will select an arbitrary
unused port.

‘python -m pydoc -n <hostname>’ will start the server listening at the
given hostname.  By default the hostname is ‘localhost’ but if you want
the server to be reached from other machines, you may want to change the
host name that the server responds to.  During development this is
especially useful if you want to run pydoc from within a container.

‘python -m pydoc -b’ will start the server and additionally open a web
browser to a module index page.  Each served page has a navigation bar
at the top where you can 'Get' help on an individual item, 'Search' all
modules with a keyword in their synopsis line, and go to the 'Module
index', 'Topics' and 'Keywords' pages.

When ‘pydoc’ generates documentation, it uses the current environment
and path to locate modules.  Thus, invoking ‘pydoc spam’ documents
precisely the version of the module you would get if you started the
Python interpreter and typed ‘import spam’.

Module docs for core modules are assumed to reside in
‘https://docs.python.org/X.Y/library/’ where ‘X’ and ‘Y’ are the major
and minor version numbers of the Python interpreter.  This can be
overridden by setting the ‘PYTHONDOCS’ environment variable to a
different URL or to a local directory containing the Library Reference
Manual pages.

Changed in version 3.2: Added the ‘-b’ option.

Changed in version 3.3: The ‘-g’ command line option was removed.

Changed in version 3.4: ‘pydoc’ now uses *note inspect.signature(): 73b.
rather than *note inspect.getfullargspec(): 73c. to extract signature
information from callables.

Changed in version 3.7: Added the ‘-n’ option.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pydoc.py


File: python.info,  Node: Python Development Mode,  Next: doctest — Test interactive Python examples,  Prev: pydoc — Documentation generator and online help system,  Up: Development Tools

5.26.3 Python Development Mode
------------------------------

Added in version 3.7.

The Python Development Mode introduces additional runtime checks that
are too expensive to be enabled by default.  It should not be more
verbose than the default if the code is correct; new warnings are only
emitted when an issue is detected.

It can be enabled using the *note -X dev: 176. command line option or by
setting the *note PYTHONDEVMODE: b06. environment variable to ‘1’.

See also *note Python debug build: 1f9.

* Menu:

* Effects of the Python Development Mode::
* ResourceWarning Example::
* Bad file descriptor error example::


File: python.info,  Node: Effects of the Python Development Mode,  Next: ResourceWarning Example,  Up: Python Development Mode

5.26.3.1 Effects of the Python Development Mode
...............................................

Enabling the Python Development Mode is similar to the following
command, but with additional effects described below:

     PYTHONMALLOC=debug PYTHONASYNCIODEBUG=1 python -W default -X faulthandler

Effects of the Python Development Mode:

   * Add ‘default’ *note warning filter: 1ee1.  The following warnings
     are shown:

        * *note DeprecationWarning: 1a5.

        * *note ImportWarning: 4fd.

        * *note PendingDeprecationWarning: 8d1.

        * *note ResourceWarning: 244.

     Normally, the above warnings are filtered by the default *note
     warning filters: 1ee1.

     It behaves as if the *note -W default: 8d0. command line option is
     used.

     Use the *note -W error: 8d0. command line option or set the *note
     PYTHONWARNINGS: bc8. environment variable to ‘error’ to treat
     warnings as errors.

   * Install debug hooks on memory allocators to check for:

        * Buffer underflow

        * Buffer overflow

        * Memory allocator API violation

        * Unsafe usage of the GIL

     See the *note PyMem_SetupDebugHooks(): c8b. C function.

     It behaves as if the *note PYTHONMALLOC: c85. environment variable
     is set to ‘debug’.

     To enable the Python Development Mode without installing debug
     hooks on memory allocators, set the *note PYTHONMALLOC: c85.
     environment variable to ‘default’.

   * Call *note faulthandler.enable(): cc4. at Python startup to install
     handlers for the *note SIGSEGV: 10be, *note SIGFPE: 10bf, *note
     SIGABRT: 10c0, *note SIGBUS: 10c1. and *note SIGILL: 10c2. signals
     to dump the Python traceback on a crash.

     It behaves as if the *note -X faulthandler: 176. command line
     option is used or if the *note PYTHONFAULTHANDLER: 10c3.
     environment variable is set to ‘1’.

   * Enable *note asyncio debug mode: 1ef2.  For example, *note asyncio:
     a. checks for coroutines that were not awaited and logs them.

     It behaves as if the *note PYTHONASYNCIODEBUG: 1ef1. environment
     variable is set to ‘1’.

   * Check the 'encoding' and 'errors' arguments for string encoding and
     decoding operations.  Examples: *note open(): 51f, *note
     str.encode(): 8de. and *note bytes.decode(): 8df.

     By default, for best performance, the 'errors' argument is only
     checked at the first encoding/decoding error and the 'encoding'
     argument is sometimes ignored for empty strings.

   * The *note io.IOBase: 1f5. destructor logs ‘close()’ exceptions.

   * Set the *note dev_mode: 1c33. attribute of *note sys.flags: 68f. to
     ‘True’.

The Python Development Mode does not enable the *note tracemalloc: ff.
module by default, because the overhead cost (to performance and memory)
would be too large.  Enabling the ‘tracemalloc’ module provides
additional information on the origin of some errors.  For example, *note
ResourceWarning: 244. logs the traceback where the resource was
allocated, and a buffer overflow error logs the traceback where the
memory block was allocated.

The Python Development Mode does not prevent the *note -O: de3. command
line option from removing *note assert: 972. statements nor from setting
*note __debug__: 7de. to ‘False’.

The Python Development Mode can only be enabled at the Python startup.
Its value can be read from *note sys.flags.dev_mode: 68f.

Changed in version 3.8: The *note io.IOBase: 1f5. destructor now logs
‘close()’ exceptions.

Changed in version 3.9: The 'encoding' and 'errors' arguments are now
checked for string encoding and decoding operations.


File: python.info,  Node: ResourceWarning Example,  Next: Bad file descriptor error example,  Prev: Effects of the Python Development Mode,  Up: Python Development Mode

5.26.3.2 ResourceWarning Example
................................

Example of a script counting the number of lines of the text file
specified in the command line:

     import sys

     def main():
         fp = open(sys.argv[1])
         nlines = len(fp.readlines())
         print(nlines)
         # The file is closed implicitly

     if __name__ == "__main__":
         main()

The script does not close the file explicitly.  By default, Python does
not emit any warning.  Example using README.txt, which has 269 lines:

     $ python script.py README.txt
     269

Enabling the Python Development Mode displays a *note ResourceWarning:
244. warning:

     $ python -X dev script.py README.txt
     269
     script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='README.rst' mode='r' encoding='UTF-8'>
       main()
     ResourceWarning: Enable tracemalloc to get the object allocation traceback

In addition, enabling *note tracemalloc: ff. shows the line where the
file was opened:

     $ python -X dev -X tracemalloc=5 script.py README.rst
     269
     script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='README.rst' mode='r' encoding='UTF-8'>
       main()
     Object allocated at (most recent call last):
       File "script.py", lineno 10
         main()
       File "script.py", lineno 4
         fp = open(sys.argv[1])

The fix is to close explicitly the file.  Example using a context
manager:

     def main():
         # Close the file explicitly when exiting the with block
         with open(sys.argv[1]) as fp:
             nlines = len(fp.readlines())
         print(nlines)

Not closing a resource explicitly can leave a resource open for way
longer than expected; it can cause severe issues upon exiting Python.
It is bad in CPython, but it is even worse in PyPy.  Closing resources
explicitly makes an application more deterministic and more reliable.


File: python.info,  Node: Bad file descriptor error example,  Prev: ResourceWarning Example,  Up: Python Development Mode

5.26.3.3 Bad file descriptor error example
..........................................

Script displaying the first line of itself:

     import os

     def main():
         fp = open(__file__)
         firstline = fp.readline()
         print(firstline.rstrip())
         os.close(fp.fileno())
         # The file is closed implicitly

     main()

By default, Python does not emit any warning:

     $ python script.py
     import os

The Python Development Mode shows a *note ResourceWarning: 244. and logs
a “Bad file descriptor” error when finalizing the file object:

     $ python -X dev script.py
     import os
     script.py:10: ResourceWarning: unclosed file <_io.TextIOWrapper name='script.py' mode='r' encoding='UTF-8'>
       main()
     ResourceWarning: Enable tracemalloc to get the object allocation traceback
     Exception ignored in: <_io.TextIOWrapper name='script.py' mode='r' encoding='UTF-8'>
     Traceback (most recent call last):
       File "script.py", line 10, in <module>
         main()
     OSError: [Errno 9] Bad file descriptor

‘os.close(fp.fileno())’ closes the file descriptor.  When the file
object finalizer tries to close the file descriptor again, it fails with
the ‘Bad file descriptor’ error.  A file descriptor must be closed only
once.  In the worst case scenario, closing it twice can lead to a crash
(see bpo-18748(1) for an example).

The fix is to remove the ‘os.close(fp.fileno())’ line, or open the file
with ‘closefd=False’.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=18748


File: python.info,  Node: doctest — Test interactive Python examples,  Next: unittest — Unit testing framework,  Prev: Python Development Mode,  Up: Development Tools

5.26.4 ‘doctest’ — Test interactive Python examples
---------------------------------------------------

'Source code:' Lib/doctest.py(1)

__________________________________________________________________

The ‘doctest’ module searches for pieces of text that look like
interactive Python sessions, and then executes those sessions to verify
that they work exactly as shown.  There are several common ways to use
doctest:

   * To check that a module’s docstrings are up-to-date by verifying
     that all interactive examples still work as documented.

   * To perform regression testing by verifying that interactive
     examples from a test file or a test object work as expected.

   * To write tutorial documentation for a package, liberally
     illustrated with input-output examples.  Depending on whether the
     examples or the expository text are emphasized, this has the flavor
     of “literate testing” or “executable documentation”.

Here’s a complete but small example module:

     """
     This is the "example" module.

     The example module supplies one function, factorial().  For example,

     >>> factorial(5)
     120
     """

     def factorial(n):
         """Return the factorial of n, an exact integer >= 0.

         >>> [factorial(n) for n in range(6)]
         [1, 1, 2, 6, 24, 120]
         >>> factorial(30)
         265252859812191058636308480000000
         >>> factorial(-1)
         Traceback (most recent call last):
             ...
         ValueError: n must be >= 0

         Factorials of floats are OK, but the float must be an exact integer:
         >>> factorial(30.1)
         Traceback (most recent call last):
             ...
         ValueError: n must be exact integer
         >>> factorial(30.0)
         265252859812191058636308480000000

         It must also not be ridiculously large:
         >>> factorial(1e100)
         Traceback (most recent call last):
             ...
         OverflowError: n too large
         """

         import math
         if not n >= 0:
             raise ValueError("n must be >= 0")
         if math.floor(n) != n:
             raise ValueError("n must be exact integer")
         if n+1 == n:  # catch a value like 1e300
             raise OverflowError("n too large")
         result = 1
         factor = 2
         while factor <= n:
             result *= factor
             factor += 1
         return result


     if __name__ == "__main__":
         import doctest
         doctest.testmod()

If you run ‘example.py’ directly from the command line, ‘doctest’ works
its magic:

     $ python example.py
     $

There’s no output!  That’s normal, and it means all the examples worked.
Pass ‘-v’ to the script, and ‘doctest’ prints a detailed log of what
it’s trying, and prints a summary at the end:

     $ python example.py -v
     Trying:
         factorial(5)
     Expecting:
         120
     ok
     Trying:
         [factorial(n) for n in range(6)]
     Expecting:
         [1, 1, 2, 6, 24, 120]
     ok

And so on, eventually ending with:

     Trying:
         factorial(1e100)
     Expecting:
         Traceback (most recent call last):
             ...
         OverflowError: n too large
     ok
     2 items passed all tests:
        1 test in __main__
        6 tests in __main__.factorial
     7 tests in 2 items.
     7 passed.
     Test passed.
     $

That’s all you need to know to start making productive use of ‘doctest’!
Jump in.  The following sections provide full details.  Note that there
are many examples of doctests in the standard Python test suite and
libraries.  Especially useful examples can be found in the standard test
file ‘Lib/test/test_doctest/test_doctest.py’.

* Menu:

* Simple Usage; Checking Examples in Docstrings: Simple Usage Checking Examples in Docstrings.
* Simple Usage; Checking Examples in a Text File: Simple Usage Checking Examples in a Text File.
* Command-line Usage::
* How It Works::
* Basic API::
* Unittest API::
* Advanced API::
* Debugging::
* Soapbox::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/doctest.py


File: python.info,  Node: Simple Usage Checking Examples in Docstrings,  Next: Simple Usage Checking Examples in a Text File,  Up: doctest — Test interactive Python examples

5.26.4.1 Simple Usage: Checking Examples in Docstrings
......................................................

The simplest way to start using doctest (but not necessarily the way
you’ll continue to do it) is to end each module ‘M’ with:

     if __name__ == "__main__":
         import doctest
         doctest.testmod()

‘doctest’ then examines docstrings in module ‘M’.

Running the module as a script causes the examples in the docstrings to
get executed and verified:

     python M.py

This won’t display anything unless an example fails, in which case the
failing example(s) and the cause(s) of the failure(s) are printed to
stdout, and the final line of output is ‘***Test Failed*** N failures.’,
where 'N' is the number of examples that failed.

Run it with the ‘-v’ switch instead:

     python M.py -v

and a detailed report of all examples tried is printed to standard
output, along with assorted summaries at the end.

You can force verbose mode by passing ‘verbose=True’ to *note testmod():
14bc, or prohibit it by passing ‘verbose=False’.  In either of those
cases, *note sys.argv: 12ab. is not examined by ‘testmod()’ (so passing
‘-v’ or not has no effect).

There is also a command line shortcut for running *note testmod(): 14bc,
see section *note Command-line Usage: 4229.

For more information on *note testmod(): 14bc, see section *note Basic
API: 422a.


File: python.info,  Node: Simple Usage Checking Examples in a Text File,  Next: Command-line Usage,  Prev: Simple Usage Checking Examples in Docstrings,  Up: doctest — Test interactive Python examples

5.26.4.2 Simple Usage: Checking Examples in a Text File
.......................................................

Another simple application of doctest is testing interactive examples in
a text file.  This can be done with the *note testfile(): 422d.
function:

     import doctest
     doctest.testfile("example.txt")

That short script executes and verifies any interactive Python examples
contained in the file ‘example.txt’.  The file content is treated as if
it were a single giant docstring; the file doesn’t need to contain a
Python program!  For example, perhaps ‘example.txt’ contains this:

     The ``example`` module
     ======================

     Using ``factorial``
     -------------------

     This is an example text file in reStructuredText format.  First import
     ``factorial`` from the ``example`` module:

         >>> from example import factorial

     Now use it:

         >>> factorial(6)
         120

Running ‘doctest.testfile("example.txt")’ then finds the error in this
documentation:

     File "./example.txt", line 14, in example.txt
     Failed example:
         factorial(6)
     Expected:
         120
     Got:
         720

As with *note testmod(): 14bc, *note testfile(): 422d. won’t display
anything unless an example fails.  If an example does fail, then the
failing example(s) and the cause(s) of the failure(s) are printed to
stdout, using the same format as ‘testmod()’.

By default, *note testfile(): 422d. looks for files in the calling
module’s directory.  See section *note Basic API: 422a. for a
description of the optional arguments that can be used to tell it to
look for files in other locations.

Like *note testmod(): 14bc, *note testfile(): 422d.’s verbosity can be
set with the ‘-v’ command-line switch or with the optional keyword
argument 'verbose'.

There is also a command line shortcut for running *note testfile():
422d, see section *note Command-line Usage: 4229.

For more information on *note testfile(): 422d, see section *note Basic
API: 422a.


File: python.info,  Node: Command-line Usage,  Next: How It Works,  Prev: Simple Usage Checking Examples in a Text File,  Up: doctest — Test interactive Python examples

5.26.4.3 Command-line Usage
...........................

The ‘doctest’ module can be invoked as a script from the command line:

     python -m doctest [-v] [-o OPTION] [-f] file [file ...]

 -- Option: -v, --verbose

     Detailed report of all examples tried is printed to standard
     output, along with assorted summaries at the end:

          python -m doctest -v example.py

     This will import ‘example.py’ as a standalone module and run *note
     testmod(): 14bc. on it.  Note that this may not work correctly if
     the file is part of a package and imports other submodules from
     that package.

     If the file name does not end with ‘.py’, ‘doctest’ infers that it
     must be run with *note testfile(): 422d. instead:

          python -m doctest -v example.txt

 -- Option: -o, --option <option>

     Option flags control various aspects of doctest’s behavior, see
     section *note Option Flags: f6b.

     Added in version 3.4.

 -- Option: -f, --fail-fast

     This is shorthand for ‘-o FAIL_FAST’.

     Added in version 3.4.


File: python.info,  Node: How It Works,  Next: Basic API,  Prev: Command-line Usage,  Up: doctest — Test interactive Python examples

5.26.4.4 How It Works
.....................

This section examines in detail how doctest works: which docstrings it
looks at, how it finds interactive examples, what execution context it
uses, how it handles exceptions, and how option flags can be used to
control its behavior.  This is the information that you need to know to
write doctest examples; for information about actually running doctest
on these examples, see the following sections.

* Menu:

* Which Docstrings Are Examined?::
* How are Docstring Examples Recognized?::
* What’s the Execution Context?::
* What About Exceptions?::
* Option Flags::
* Directives::
* Warnings: Warnings<2>.


File: python.info,  Node: Which Docstrings Are Examined?,  Next: How are Docstring Examples Recognized?,  Up: How It Works

5.26.4.5 Which Docstrings Are Examined?
.......................................

The module docstring, and all function, class and method docstrings are
searched.  Objects imported into the module are not searched.

In addition, there are cases when you want tests to be part of a module
but not part of the help text, which requires that the tests not be
included in the docstring.  Doctest looks for a module-level variable
called ‘__test__’ and uses it to locate other tests.  If ‘M.__test__’
exists, it must be a dict, and each entry maps a (string) name to a
function object, class object, or string.  Function and class object
docstrings found from ‘M.__test__’ are searched, and strings are treated
as if they were docstrings.  In output, a key ‘K’ in ‘M.__test__’
appears with name ‘M.__test__.K’.

For example, place this block of code at the top of ‘example.py’:

     __test__ = {
         'numbers': """
     >>> factorial(6)
     720

     >>> [factorial(n) for n in range(6)]
     [1, 1, 2, 6, 24, 120]
     """
     }

The value of ‘example.__test__["numbers"]’ will be treated as a
docstring and all the tests inside it will be run.  It is important to
note that the value can be mapped to a function, class object, or
module; if so, ‘doctest’ searches them recursively for docstrings, which
are then scanned for tests.

Any classes found are recursively searched similarly, to test docstrings
in their contained methods and nested classes.

     Note: ‘doctest’ can only automatically discover classes and
     functions that are defined at the module level or inside other
     classes.

     Since nested classes and functions only exist when an outer
     function is called, they cannot be discovered.  Define them outside
     to make them visible.


File: python.info,  Node: How are Docstring Examples Recognized?,  Next: What’s the Execution Context?,  Prev: Which Docstrings Are Examined?,  Up: How It Works

5.26.4.6 How are Docstring Examples Recognized?
...............................................

In most cases a copy-and-paste of an interactive console session works
fine, but doctest isn’t trying to do an exact emulation of any specific
Python shell.

     >>> # comments are ignored
     >>> x = 12
     >>> x
     12
     >>> if x == 13:
     ...     print("yes")
     ... else:
     ...     print("no")
     ...     print("NO")
     ...     print("NO!!!")
     ...
     no
     NO
     NO!!!
     >>>

Any expected output must immediately follow the final ‘'>>> '’ or ‘'...
'’ line containing the code, and the expected output (if any) extends to
the next ‘'>>> '’ or all-whitespace line.

The fine print:

   * Expected output cannot contain an all-whitespace line, since such a
     line is taken to signal the end of expected output.  If expected
     output does contain a blank line, put ‘<BLANKLINE>’ in your doctest
     example each place a blank line is expected.

   * All hard tab characters are expanded to spaces, using 8-column tab
     stops.  Tabs in output generated by the tested code are not
     modified.  Because any hard tabs in the sample output 'are'
     expanded, this means that if the code output includes hard tabs,
     the only way the doctest can pass is if the *note
     NORMALIZE_WHITESPACE: 423c. option or *note directive: 423d. is in
     effect.  Alternatively, the test can be rewritten to capture the
     output and compare it to an expected value as part of the test.
     This handling of tabs in the source was arrived at through trial
     and error, and has proven to be the least error prone way of
     handling them.  It is possible to use a different algorithm for
     handling tabs by writing a custom *note DocTestParser: 423e. class.

   * Output to stdout is captured, but not output to stderr (exception
     tracebacks are captured via a different means).

   * If you continue a line via backslashing in an interactive session,
     or for any other reason use a backslash, you should use a raw
     docstring, which will preserve your backslashes exactly as you type
     them:

          >>> def f(x):
          ...     r'''Backslashes in a raw docstring: m\n'''
          ...
          >>> print(f.__doc__)
          Backslashes in a raw docstring: m\n

     Otherwise, the backslash will be interpreted as part of the string.
     For example, the ‘\n’ above would be interpreted as a newline
     character.  Alternatively, you can double each backslash in the
     doctest version (and not use a raw string):

          >>> def f(x):
          ...     '''Backslashes in a raw docstring: m\\n'''
          ...
          >>> print(f.__doc__)
          Backslashes in a raw docstring: m\n

   * The starting column doesn’t matter:

          >>> assert "Easy!"
                >>> import math
                    >>> math.floor(1.9)
                    1

     and as many leading whitespace characters are stripped from the
     expected output as appeared in the initial ‘'>>> '’ line that
     started the example.


File: python.info,  Node: What’s the Execution Context?,  Next: What About Exceptions?,  Prev: How are Docstring Examples Recognized?,  Up: How It Works

5.26.4.7 What’s the Execution Context?
......................................

By default, each time ‘doctest’ finds a docstring to test, it uses a
'shallow copy' of ‘M’’s globals, so that running tests doesn’t change
the module’s real globals, and so that one test in ‘M’ can’t leave
behind crumbs that accidentally allow another test to work.  This means
examples can freely use any names defined at top-level in ‘M’, and names
defined earlier in the docstring being run.  Examples cannot see names
defined in other docstrings.

You can force use of your own dict as the execution context by passing
‘globs=your_dict’ to *note testmod(): 14bc. or *note testfile(): 422d.
instead.


File: python.info,  Node: What About Exceptions?,  Next: Option Flags,  Prev: What’s the Execution Context?,  Up: How It Works

5.26.4.8 What About Exceptions?
...............................

No problem, provided that the traceback is the only output produced by
the example: just paste in the traceback.  (1)  Since tracebacks contain
details that are likely to change rapidly (for example, exact file paths
and line numbers), this is one case where doctest works hard to be
flexible in what it accepts.

Simple example:

     >>> [1, 2, 3].remove(42)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ValueError: list.remove(x): x not in list

That doctest succeeds if *note ValueError: 202. is raised, with the
‘list.remove(x): x not in list’ detail as shown.

The expected output for an exception must start with a traceback header,
which may be either of the following two lines, indented the same as the
first line of the example:

     Traceback (most recent call last):
     Traceback (innermost last):

The traceback header is followed by an optional traceback stack, whose
contents are ignored by doctest.  The traceback stack is typically
omitted, or copied verbatim from an interactive session.

The traceback stack is followed by the most interesting part: the
line(s) containing the exception type and detail.  This is usually the
last line of a traceback, but can extend across multiple lines if the
exception has a multi-line detail:

     >>> raise ValueError('multi\n    line\ndetail')
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     ValueError: multi
         line
     detail

The last three lines (starting with *note ValueError: 202.) are compared
against the exception’s type and detail, and the rest are ignored.

Best practice is to omit the traceback stack, unless it adds significant
documentation value to the example.  So the last example is probably
better as:

     >>> raise ValueError('multi\n    line\ndetail')
     Traceback (most recent call last):
         ...
     ValueError: multi
         line
     detail

Note that tracebacks are treated very specially.  In particular, in the
rewritten example, the use of ‘...’ is independent of doctest’s *note
ELLIPSIS: 14bd. option.  The ellipsis in that example could be left out,
or could just as well be three (or three hundred) commas or digits, or
an indented transcript of a Monty Python skit.

Some details you should read once, but won’t need to remember:

   * Doctest can’t guess whether your expected output came from an
     exception traceback or from ordinary printing.  So, e.g., an
     example that expects ‘ValueError: 42 is prime’ will pass whether
     *note ValueError: 202. is actually raised or if the example merely
     prints that traceback text.  In practice, ordinary output rarely
     begins with a traceback header line, so this doesn’t create real
     problems.

   * Each line of the traceback stack (if present) must be indented
     further than the first line of the example, 'or' start with a
     non-alphanumeric character.  The first line following the traceback
     header indented the same and starting with an alphanumeric is taken
     to be the start of the exception detail.  Of course this does the
     right thing for genuine tracebacks.

   * When the *note IGNORE_EXCEPTION_DETAIL: 1352. doctest option is
     specified, everything following the leftmost colon and any module
     information in the exception name is ignored.

   * The interactive shell omits the traceback header line for some
     *note SyntaxError: 18d.s.  But doctest uses the traceback header
     line to distinguish exceptions from non-exceptions.  So in the rare
     case where you need to test a ‘SyntaxError’ that omits the
     traceback header, you will need to manually add the traceback
     header line to your test example.

   * For some exceptions, Python displays the position of the error
     using ‘^’ markers and tildes:

          >>> 1 + None
            File "<stdin>", line 1
              1 + None
              ~~^~~~~~
          TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

     Since the lines showing the position of the error come before the
     exception type and detail, they are not checked by doctest.  For
     example, the following test would pass, even though it puts the ‘^’
     marker in the wrong location:

          >>> 1 + None
            File "<stdin>", line 1
              1 + None
              ^~~~~~~~
          TypeError: unsupported operand type(s) for +: 'int' and 'NoneType'

   ---------- Footnotes ----------

   (1) Examples containing both expected output and an exception are not
supported.  Trying to guess where one ends and the other begins is too
error-prone, and that also makes for a confusing test.


File: python.info,  Node: Option Flags,  Next: Directives,  Prev: What About Exceptions?,  Up: How It Works

5.26.4.9 Option Flags
.....................

A number of option flags control various aspects of doctest’s behavior.
Symbolic names for the flags are supplied as module constants, which can
be *note bitwise ORed: 2225. together and passed to various functions.
The names can also be used in *note doctest directives: 423d, and may be
passed to the doctest command line interface via the ‘-o’ option.

The first group of options define test semantics, controlling aspects of
how doctest decides whether actual output matches an example’s expected
output:

 -- Data: doctest.DONT_ACCEPT_TRUE_FOR_1

     By default, if an expected output block contains just ‘1’, an
     actual output block containing just ‘1’ or just ‘True’ is
     considered to be a match, and similarly for ‘0’ versus ‘False’.
     When *note DONT_ACCEPT_TRUE_FOR_1: 4245. is specified, neither
     substitution is allowed.  The default behavior caters to that
     Python changed the return type of many functions from integer to
     boolean; doctests expecting “little integer” output still work in
     these cases.  This option will probably go away, but not for
     several years.

 -- Data: doctest.DONT_ACCEPT_BLANKLINE

     By default, if an expected output block contains a line containing
     only the string ‘<BLANKLINE>’, then that line will match a blank
     line in the actual output.  Because a genuinely blank line delimits
     the expected output, this is the only way to communicate that a
     blank line is expected.  When *note DONT_ACCEPT_BLANKLINE: 4246. is
     specified, this substitution is not allowed.

 -- Data: doctest.NORMALIZE_WHITESPACE

     When specified, all sequences of whitespace (blanks and newlines)
     are treated as equal.  Any sequence of whitespace within the
     expected output will match any sequence of whitespace within the
     actual output.  By default, whitespace must match exactly.  *note
     NORMALIZE_WHITESPACE: 423c. is especially useful when a line of
     expected output is very long, and you want to wrap it across
     multiple lines in your source.

 -- Data: doctest.ELLIPSIS

     When specified, an ellipsis marker (‘...’) in the expected output
     can match any substring in the actual output.  This includes
     substrings that span line boundaries, and empty substrings, so it’s
     best to keep usage of this simple.  Complicated uses can lead to
     the same kinds of “oops, it matched too much!” surprises that ‘.*’
     is prone to in regular expressions.

 -- Data: doctest.IGNORE_EXCEPTION_DETAIL

     When specified, doctests expecting exceptions pass so long as an
     exception of the expected type is raised, even if the details
     (message and fully qualified exception name) don’t match.

     For example, an example expecting ‘ValueError: 42’ will pass if the
     actual exception raised is ‘ValueError: 3*14’, but will fail if,
     say, a *note TypeError: 2c3. is raised instead.  It will also
     ignore any fully qualified name included before the exception
     class, which can vary between implementations and versions of
     Python and the code/libraries in use.  Hence, all three of these
     variations will work with the flag specified:

          >>> raise Exception('message')
          Traceback (most recent call last):
          Exception: message

          >>> raise Exception('message')
          Traceback (most recent call last):
          builtins.Exception: message

          >>> raise Exception('message')
          Traceback (most recent call last):
          __main__.Exception: message

     Note that *note ELLIPSIS: 14bd. can also be used to ignore the
     details of the exception message, but such a test may still fail
     based on whether the module name is present or matches exactly.

     Changed in version 3.2: *note IGNORE_EXCEPTION_DETAIL: 1352. now
     also ignores any information relating to the module containing the
     exception under test.

 -- Data: doctest.SKIP

     When specified, do not run the example at all.  This can be useful
     in contexts where doctest examples serve as both documentation and
     test cases, and an example should be included for documentation
     purposes, but should not be checked.  E.g., the example’s output
     might be random; or the example might depend on resources which
     would be unavailable to the test driver.

     The SKIP flag can also be used for temporarily “commenting out”
     examples.

 -- Data: doctest.COMPARISON_FLAGS

     A bitmask or’ing together all the comparison flags above.

The second group of options controls how test failures are reported:

 -- Data: doctest.REPORT_UDIFF

     When specified, failures that involve multi-line expected and
     actual outputs are displayed using a unified diff.

 -- Data: doctest.REPORT_CDIFF

     When specified, failures that involve multi-line expected and
     actual outputs will be displayed using a context diff.

 -- Data: doctest.REPORT_NDIFF

     When specified, differences are computed by ‘difflib.Differ’, using
     the same algorithm as the popular ‘ndiff.py’ utility.  This is the
     only method that marks differences within lines as well as across
     lines.  For example, if a line of expected output contains digit
     ‘1’ where actual output contains letter ‘l’, a line is inserted
     with a caret marking the mismatching column positions.

 -- Data: doctest.REPORT_ONLY_FIRST_FAILURE

     When specified, display the first failing example in each doctest,
     but suppress output for all remaining examples.  This will prevent
     doctest from reporting correct examples that break because of
     earlier failures; but it might also hide incorrect examples that
     fail independently of the first failure.  When *note
     REPORT_ONLY_FIRST_FAILURE: 4249. is specified, the remaining
     examples are still run, and still count towards the total number of
     failures reported; only the output is suppressed.

 -- Data: doctest.FAIL_FAST

     When specified, exit after the first failing example and don’t
     attempt to run the remaining examples.  Thus, the number of
     failures reported will be at most 1.  This flag may be useful
     during debugging, since examples after the first failure won’t even
     produce debugging output.

 -- Data: doctest.REPORTING_FLAGS

     A bitmask or’ing together all the reporting flags above.

There is also a way to register new option flag names, though this isn’t
useful unless you intend to extend ‘doctest’ internals via subclassing:

 -- Function: doctest.register_optionflag (name)

     Create a new option flag with a given name, and return the new
     flag’s integer value.  ‘register_optionflag()’ can be used when
     subclassing *note OutputChecker: 424c. or *note DocTestRunner:
     424d. to create new options that are supported by your subclasses.
     ‘register_optionflag()’ should always be called using the following
     idiom:

          MY_FLAG = register_optionflag('MY_FLAG')


File: python.info,  Node: Directives,  Next: Warnings<2>,  Prev: Option Flags,  Up: How It Works

5.26.4.10 Directives
....................

Doctest directives may be used to modify the *note option flags: f6b.
for an individual example.  Doctest directives are special Python
comments following an example’s source code:

     directive             ::= "#" "doctest:" *note directive_options: 4250.
     directive_options     ::= *note directive_option: 4251. ("," *note directive_option: 4251.)*
     directive_option      ::= *note on_or_off: 4252. *note directive_option_name: 4253.
     on_or_off             ::= "+" | "-"
     directive_option_name ::= "DONT_ACCEPT_BLANKLINE" | "NORMALIZE_WHITESPACE" | ...

Whitespace is not allowed between the ‘+’ or ‘-’ and the directive
option name.  The directive option name can be any of the option flag
names explained above.

An example’s doctest directives modify doctest’s behavior for that
single example.  Use ‘+’ to enable the named behavior, or ‘-’ to disable
it.

For example, this test passes:

     >>> print(list(range(20)))  # doctest: +NORMALIZE_WHITESPACE
     [0,   1,  2,  3,  4,  5,  6,  7,  8,  9,
     10,  11, 12, 13, 14, 15, 16, 17, 18, 19]

Without the directive it would fail, both because the actual output
doesn’t have two blanks before the single-digit list elements, and
because the actual output is on a single line.  This test also passes,
and also requires a directive to do so:

     >>> print(list(range(20)))  # doctest: +ELLIPSIS
     [0, 1, ..., 18, 19]

Multiple directives can be used on a single physical line, separated by
commas:

     >>> print(list(range(20)))  # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
     [0,    1, ...,   18,    19]

If multiple directive comments are used for a single example, then they
are combined:

     >>> print(list(range(20)))  # doctest: +ELLIPSIS
     ...                         # doctest: +NORMALIZE_WHITESPACE
     [0,    1, ...,   18,    19]

As the previous example shows, you can add ‘...’ lines to your example
containing only directives.  This can be useful when an example is too
long for a directive to comfortably fit on the same line:

     >>> print(list(range(5)) + list(range(10, 20)) + list(range(30, 40)))
     ... # doctest: +ELLIPSIS
     [0, ..., 4, 10, ..., 19, 30, ..., 39]

Note that since all options are disabled by default, and directives
apply only to the example they appear in, enabling options (via ‘+’ in a
directive) is usually the only meaningful choice.  However, option flags
can also be passed to functions that run doctests, establishing
different defaults.  In such cases, disabling an option via ‘-’ in a
directive can be useful.


File: python.info,  Node: Warnings<2>,  Prev: Directives,  Up: How It Works

5.26.4.11 Warnings
..................

‘doctest’ is serious about requiring exact matches in expected output.
If even a single character doesn’t match, the test fails.  This will
probably surprise you a few times, as you learn exactly what Python does
and doesn’t guarantee about output.  For example, when printing a set,
Python doesn’t guarantee that the element is printed in any particular
order, so a test like

     >>> foo()
     {"spam", "eggs"}

is vulnerable!  One workaround is to do

     >>> foo() == {"spam", "eggs"}
     True

instead.  Another is to do

     >>> d = sorted(foo())
     >>> d
     ['eggs', 'spam']

There are others, but you get the idea.

Another bad idea is to print things that embed an object address, like

     >>> id(1.0)  # certain to fail some of the time
     7948648
     >>> class C: pass
     >>> C()  # the default repr() for instances embeds an address
     <C object at 0x00AC18F0>

The *note ELLIPSIS: 14bd. directive gives a nice approach for the last
example:

     >>> C()  # doctest: +ELLIPSIS
     <C object at 0x...>

Floating-point numbers are also subject to small output variations
across platforms, because Python defers to the platform C library for
some floating-point calculations, and C libraries vary widely in quality
here.

     >>> 1000**0.1  # risky
     1.9952623149688797
     >>> round(1000**0.1, 9) # safer
     1.995262315
     >>> print(f'{1000**0.1:.4f}') # much safer
     1.9953

Numbers of the form ‘I/2.**J’ are safe across all platforms, and I often
contrive doctest examples to produce numbers of that form:

     >>> 3./4  # utterly safe
     0.75

Simple fractions are also easier for people to understand, and that
makes for better documentation.


File: python.info,  Node: Basic API,  Next: Unittest API,  Prev: How It Works,  Up: doctest — Test interactive Python examples

5.26.4.12 Basic API
...................

The functions *note testmod(): 14bc. and *note testfile(): 422d. provide
a simple interface to doctest that should be sufficient for most basic
uses.  For a less formal introduction to these two functions, see
sections *note Simple Usage; Checking Examples in Docstrings: 4227. and
*note Simple Usage; Checking Examples in a Text File: 422b.

 -- Function: doctest.testfile (filename, module_relative=True,
          name=None, package=None, globs=None, verbose=None,
          report=True, optionflags=0, extraglobs=None,
          raise_on_error=False, parser=DocTestParser(), encoding=None)

     All arguments except 'filename' are optional, and should be
     specified in keyword form.

     Test examples in the file named 'filename'.  Return
     ‘(failure_count, test_count)’.

     Optional argument 'module_relative' specifies how the filename
     should be interpreted:

        * If 'module_relative' is ‘True’ (the default), then 'filename'
          specifies an OS-independent module-relative path.  By default,
          this path is relative to the calling module’s directory; but
          if the 'package' argument is specified, then it is relative to
          that package.  To ensure OS-independence, 'filename' should
          use ‘/’ characters to separate path segments, and may not be
          an absolute path (i.e., it may not begin with ‘/’).

        * If 'module_relative' is ‘False’, then 'filename' specifies an
          OS-specific path.  The path may be absolute or relative;
          relative paths are resolved with respect to the current
          working directory.

     Optional argument 'name' gives the name of the test; by default, or
     if ‘None’, ‘os.path.basename(filename)’ is used.

     Optional argument 'package' is a Python package or the name of a
     Python package whose directory should be used as the base directory
     for a module-relative filename.  If no package is specified, then
     the calling module’s directory is used as the base directory for
     module-relative filenames.  It is an error to specify 'package' if
     'module_relative' is ‘False’.

     Optional argument 'globs' gives a dict to be used as the globals
     when executing examples.  A new shallow copy of this dict is
     created for the doctest, so its examples start with a clean slate.
     By default, or if ‘None’, a new empty dict is used.

     Optional argument 'extraglobs' gives a dict merged into the globals
     used to execute examples.  This works like *note dict.update():
     14b4.: if 'globs' and 'extraglobs' have a common key, the
     associated value in 'extraglobs' appears in the combined dict.  By
     default, or if ‘None’, no extra globals are used.  This is an
     advanced feature that allows parameterization of doctests.  For
     example, a doctest can be written for a base class, using a generic
     name for the class, then reused to test any number of subclasses by
     passing an 'extraglobs' dict mapping the generic name to the
     subclass to be tested.

     Optional argument 'verbose' prints lots of stuff if true, and
     prints only failures if false; by default, or if ‘None’, it’s true
     if and only if ‘'-v'’ is in *note sys.argv: 12ab.

     Optional argument 'report' prints a summary at the end when true,
     else prints nothing at the end.  In verbose mode, the summary is
     detailed, else the summary is very brief (in fact, empty if all
     tests passed).

     Optional argument 'optionflags' (default value ‘0’) takes the *note
     bitwise OR: 2225. of option flags.  See section *note Option Flags:
     f6b.

     Optional argument 'raise_on_error' defaults to false.  If true, an
     exception is raised upon the first failure or unexpected exception
     in an example.  This allows failures to be post-mortem debugged.
     Default behavior is to continue running examples.

     Optional argument 'parser' specifies a *note DocTestParser: 423e.
     (or subclass) that should be used to extract tests from the files.
     It defaults to a normal parser (i.e., ‘DocTestParser()’).

     Optional argument 'encoding' specifies an encoding that should be
     used to convert the file to unicode.

 -- Function: doctest.testmod (m=None, name=None, globs=None,
          verbose=None, report=True, optionflags=0, extraglobs=None,
          raise_on_error=False, exclude_empty=False)

     All arguments are optional, and all except for 'm' should be
     specified in keyword form.

     Test examples in docstrings in functions and classes reachable from
     module 'm' (or module *note __main__: 1. if 'm' is not supplied or
     is ‘None’), starting with ‘m.__doc__’.

     Also test examples reachable from dict ‘m.__test__’, if it exists.
     ‘m.__test__’ maps names (strings) to functions, classes and
     strings; function and class docstrings are searched for examples;
     strings are searched directly, as if they were docstrings.

     Only docstrings attached to objects belonging to module 'm' are
     searched.

     Return ‘(failure_count, test_count)’.

     Optional argument 'name' gives the name of the module; by default,
     or if ‘None’, ‘m.__name__’ is used.

     Optional argument 'exclude_empty' defaults to false.  If true,
     objects for which no doctests are found are excluded from
     consideration.  The default is a backward compatibility hack, so
     that code still using *note doctest.master.summarize: 4257. in
     conjunction with ‘testmod()’ continues to get output for objects
     with no tests.  The 'exclude_empty' argument to the newer *note
     DocTestFinder: 173b. constructor defaults to true.

     Optional arguments 'extraglobs', 'verbose', 'report',
     'optionflags', 'raise_on_error', and 'globs' are the same as for
     function *note testfile(): 422d. above, except that 'globs'
     defaults to ‘m.__dict__’.

 -- Function: doctest.run_docstring_examples (f, globs, verbose=False,
          name='NoName', compileflags=None, optionflags=0)

     Test examples associated with object 'f'; for example, 'f' may be a
     string, a module, a function, or a class object.

     A shallow copy of dictionary argument 'globs' is used for the
     execution context.

     Optional argument 'name' is used in failure messages, and defaults
     to ‘"NoName"’.

     If optional argument 'verbose' is true, output is generated even if
     there are no failures.  By default, output is generated only in
     case of an example failure.

     Optional argument 'compileflags' gives the set of flags that should
     be used by the Python compiler when running the examples.  By
     default, or if ‘None’, flags are deduced corresponding to the set
     of future features found in 'globs'.

     Optional argument 'optionflags' works as for function *note
     testfile(): 422d. above.


File: python.info,  Node: Unittest API,  Next: Advanced API,  Prev: Basic API,  Up: doctest — Test interactive Python examples

5.26.4.13 Unittest API
......................

As your collection of doctest’ed modules grows, you’ll want a way to run
all their doctests systematically.  ‘doctest’ provides two functions
that can be used to create *note unittest: 106. test suites from modules
and text files containing doctests.  To integrate with ‘unittest’ test
discovery, include a *note load_tests: 425b. function in your test
module:

     import unittest
     import doctest
     import my_module_with_doctests

     def load_tests(loader, tests, ignore):
         tests.addTests(doctest.DocTestSuite(my_module_with_doctests))
         return tests

There are two main functions for creating *note unittest.TestSuite: e26.
instances from text files and modules with doctests:

 -- Function: doctest.DocFileSuite (*paths, module_relative=True,
          package=None, setUp=None, tearDown=None, globs=None,
          optionflags=0, parser=DocTestParser(), encoding=None)

     Convert doctest tests from one or more text files to a *note
     unittest.TestSuite: e26.

     The returned *note unittest.TestSuite: e26. is to be run by the
     unittest framework and runs the interactive examples in each file.
     If an example in any file fails, then the synthesized unit test
     fails, and a *note failureException: 425d. exception is raised
     showing the name of the file containing the test and a (sometimes
     approximate) line number.  If all the examples in a file are
     skipped, then the synthesized unit test is also marked as skipped.

     Pass one or more paths (as strings) to text files to be examined.

     Options may be provided as keyword arguments:

     Optional argument 'module_relative' specifies how the filenames in
     'paths' should be interpreted:

        * If 'module_relative' is ‘True’ (the default), then each
          filename in 'paths' specifies an OS-independent
          module-relative path.  By default, this path is relative to
          the calling module’s directory; but if the 'package' argument
          is specified, then it is relative to that package.  To ensure
          OS-independence, each filename should use ‘/’ characters to
          separate path segments, and may not be an absolute path (i.e.,
          it may not begin with ‘/’).

        * If 'module_relative' is ‘False’, then each filename in 'paths'
          specifies an OS-specific path.  The path may be absolute or
          relative; relative paths are resolved with respect to the
          current working directory.

     Optional argument 'package' is a Python package or the name of a
     Python package whose directory should be used as the base directory
     for module-relative filenames in 'paths'.  If no package is
     specified, then the calling module’s directory is used as the base
     directory for module-relative filenames.  It is an error to specify
     'package' if 'module_relative' is ‘False’.

     Optional argument 'setUp' specifies a set-up function for the test
     suite.  This is called before running the tests in each file.  The
     'setUp' function will be passed a *note DocTest: 17c2. object.  The
     'setUp' function can access the test globals as the *note globs:
     425e. attribute of the test passed.

     Optional argument 'tearDown' specifies a tear-down function for the
     test suite.  This is called after running the tests in each file.
     The 'tearDown' function will be passed a *note DocTest: 17c2.
     object.  The 'tearDown' function can access the test globals as the
     *note globs: 425e. attribute of the test passed.

     Optional argument 'globs' is a dictionary containing the initial
     global variables for the tests.  A new copy of this dictionary is
     created for each test.  By default, 'globs' is a new empty
     dictionary.

     Optional argument 'optionflags' specifies the default doctest
     options for the tests, created by or-ing together individual option
     flags.  See section *note Option Flags: f6b.  See function *note
     set_unittest_reportflags(): 425f. below for a better way to set
     reporting options.

     Optional argument 'parser' specifies a *note DocTestParser: 423e.
     (or subclass) that should be used to extract tests from the files.
     It defaults to a normal parser (i.e., ‘DocTestParser()’).

     Optional argument 'encoding' specifies an encoding that should be
     used to convert the file to unicode.

     The global ‘__file__’ is added to the globals provided to doctests
     loaded from a text file using ‘DocFileSuite()’.

 -- Function: doctest.DocTestSuite (module=None, globs=None,
          extraglobs=None, test_finder=None, setUp=None, tearDown=None,
          optionflags=0, checker=None)

     Convert doctest tests for a module to a *note unittest.TestSuite:
     e26.

     The returned *note unittest.TestSuite: e26. is to be run by the
     unittest framework and runs each doctest in the module.  Each
     docstring is run as a separate unit test.  If any of the doctests
     fail, then the synthesized unit test fails, and a *note
     unittest.TestCase.failureException: 425d. exception is raised
     showing the name of the file containing the test and a (sometimes
     approximate) line number.  If all the examples in a docstring are
     skipped, then the

     Optional argument 'module' provides the module to be tested.  It
     can be a module object or a (possibly dotted) module name.  If not
     specified, the module calling this function is used.

     Optional argument 'globs' is a dictionary containing the initial
     global variables for the tests.  A new copy of this dictionary is
     created for each test.  By default, 'globs' is the module’s *note
     __dict__: 20d1.

     Optional argument 'extraglobs' specifies an extra set of global
     variables, which is merged into 'globs'.  By default, no extra
     globals are used.

     Optional argument 'test_finder' is the *note DocTestFinder: 173b.
     object (or a drop-in replacement) that is used to extract doctests
     from the module.

     Optional arguments 'setUp', 'tearDown', and 'optionflags' are the
     same as for function *note DocFileSuite(): 425c. above, but they
     are called for each docstring.

     This function uses the same search technique as *note testmod():
     14bc.

     Changed in version 3.5: ‘DocTestSuite()’ returns an empty *note
     unittest.TestSuite: e26. if 'module' contains no docstrings instead
     of raising *note ValueError: 202.

Under the covers, *note DocTestSuite(): e25. creates a *note
unittest.TestSuite: e26. out of ‘doctest.DocTestCase’ instances, and
‘DocTestCase’ is a subclass of *note unittest.TestCase: 451.
‘DocTestCase’ isn’t documented here (it’s an internal detail), but
studying its code can answer questions about the exact details of *note
unittest: 106. integration.

Similarly, *note DocFileSuite(): 425c. creates a *note
unittest.TestSuite: e26. out of ‘doctest.DocFileCase’ instances, and
‘DocFileCase’ is a subclass of ‘DocTestCase’.

So both ways of creating a *note unittest.TestSuite: e26. run instances
of ‘DocTestCase’.  This is important for a subtle reason: when you run
‘doctest’ functions yourself, you can control the ‘doctest’ options in
use directly, by passing option flags to ‘doctest’ functions.  However,
if you’re writing a *note unittest: 106. framework, ‘unittest’
ultimately controls when and how tests get run.  The framework author
typically wants to control ‘doctest’ reporting options (perhaps, e.g.,
specified by command line options), but there’s no way to pass options
through ‘unittest’ to ‘doctest’ test runners.

For this reason, ‘doctest’ also supports a notion of ‘doctest’ reporting
flags specific to *note unittest: 106. support, via this function:

 -- Function: doctest.set_unittest_reportflags (flags)

     Set the ‘doctest’ reporting flags to use.

     Argument 'flags' takes the *note bitwise OR: 2225. of option flags.
     See section *note Option Flags: f6b.  Only “reporting flags” can be
     used.

     This is a module-global setting, and affects all future doctests
     run by module *note unittest: 106.: the ‘runTest()’ method of
     ‘DocTestCase’ looks at the option flags specified for the test case
     when the ‘DocTestCase’ instance was constructed.  If no reporting
     flags were specified (which is the typical and expected case),
     ‘doctest’’s ‘unittest’ reporting flags are *note bitwise ORed:
     2225. into the option flags, and the option flags so augmented are
     passed to the *note DocTestRunner: 424d. instance created to run
     the doctest.  If any reporting flags were specified when the
     ‘DocTestCase’ instance was constructed, ‘doctest’’s ‘unittest’
     reporting flags are ignored.

     The value of the *note unittest: 106. reporting flags in effect
     before the function was called is returned by the function.


File: python.info,  Node: Advanced API,  Next: Debugging,  Prev: Unittest API,  Up: doctest — Test interactive Python examples

5.26.4.14 Advanced API
......................

The basic API is a simple wrapper that’s intended to make doctest easy
to use.  It is fairly flexible, and should meet most users’ needs;
however, if you require more fine-grained control over testing, or wish
to extend doctest’s capabilities, then you should use the advanced API.

The advanced API revolves around two container classes, which are used
to store the interactive examples extracted from doctest cases:

   * *note Example: 4262.: A single Python *note statement: 2951, paired
     with its expected output.

   * *note DocTest: 17c2.: A collection of *note Example: 4262.s,
     typically extracted from a single docstring or text file.

Additional processing classes are defined to find, parse, and run, and
check doctest examples:

   * *note DocTestFinder: 173b.: Finds all docstrings in a given module,
     and uses a *note DocTestParser: 423e. to create a *note DocTest:
     17c2. from every docstring that contains interactive examples.

   * *note DocTestParser: 423e.: Creates a *note DocTest: 17c2. object
     from a string (such as an object’s docstring).

   * *note DocTestRunner: 424d.: Executes the examples in a *note
     DocTest: 17c2, and uses an *note OutputChecker: 424c. to verify
     their output.

   * *note OutputChecker: 424c.: Compares the actual output from a
     doctest example with the expected output, and decides whether they
     match.

The relationships among these processing classes are summarized in the
following diagram:

                                 list of:
     +------+                   +---------+
     |module| --DocTestFinder-> | DocTest | --DocTestRunner-> results
     +------+    |        ^     +---------+     |       ^    (printed)
                 |        |     | Example |     |       |
                 v        |     |   ...   |     v       |
                DocTestParser   | Example |   OutputChecker
                                +---------+

* Menu:

* DocTest Objects::
* Example Objects::
* DocTestFinder objects::
* DocTestParser objects::
* TestResults objects::
* DocTestRunner objects::
* OutputChecker objects::


File: python.info,  Node: DocTest Objects,  Next: Example Objects,  Up: Advanced API

5.26.4.15 DocTest Objects
.........................

 -- Class: doctest.DocTest (examples, globs, name, filename, lineno,
          docstring)

     A collection of doctest examples that should be run in a single
     namespace.  The constructor arguments are used to initialize the
     attributes of the same names.

     ‘DocTest’ defines the following attributes.  They are initialized
     by the constructor, and should not be modified directly.

      -- Attribute: examples

          A list of *note Example: 4262. objects encoding the individual
          interactive Python examples that should be run by this test.

      -- Attribute: globs

          The namespace (aka globals) that the examples should be run
          in.  This is a dictionary mapping names to values.  Any
          changes to the namespace made by the examples (such as binding
          new variables) will be reflected in *note globs: 425e. after
          the test is run.

      -- Attribute: name

          A string name identifying the ‘DocTest’.  Typically, this is
          the name of the object or file that the test was extracted
          from.

      -- Attribute: filename

          The name of the file that this ‘DocTest’ was extracted from;
          or ‘None’ if the filename is unknown, or if the ‘DocTest’ was
          not extracted from a file.

      -- Attribute: lineno

          The line number within *note filename: 4267. where this
          ‘DocTest’ begins, or ‘None’ if the line number is unavailable.
          This line number is zero-based with respect to the beginning
          of the file.

      -- Attribute: docstring

          The string that the test was extracted from, or ‘None’ if the
          string is unavailable, or if the test was not extracted from a
          string.


File: python.info,  Node: Example Objects,  Next: DocTestFinder objects,  Prev: DocTest Objects,  Up: Advanced API

5.26.4.16 Example Objects
.........................

 -- Class: doctest.Example (source, want, exc_msg=None, lineno=0,
          indent=0, options=None)

     A single interactive example, consisting of a Python statement and
     its expected output.  The constructor arguments are used to
     initialize the attributes of the same names.

     ‘Example’ defines the following attributes.  They are initialized
     by the constructor, and should not be modified directly.

      -- Attribute: source

          A string containing the example’s source code.  This source
          code consists of a single Python statement, and always ends
          with a newline; the constructor adds a newline when necessary.

      -- Attribute: want

          The expected output from running the example’s source code
          (either from stdout, or a traceback in case of exception).
          *note want: 426c. ends with a newline unless no output is
          expected, in which case it’s an empty string.  The constructor
          adds a newline when necessary.

      -- Attribute: exc_msg

          The exception message generated by the example, if the example
          is expected to generate an exception; or ‘None’ if it is not
          expected to generate an exception.  This exception message is
          compared against the return value of *note
          traceback.format_exception_only(): 854.  *note exc_msg: 426d.
          ends with a newline unless it’s ‘None’.  The constructor adds
          a newline if needed.

      -- Attribute: lineno

          The line number within the string containing this example
          where the example begins.  This line number is zero-based with
          respect to the beginning of the containing string.

      -- Attribute: indent

          The example’s indentation in the containing string, i.e., the
          number of space characters that precede the example’s first
          prompt.

      -- Attribute: options

          A dictionary mapping from option flags to ‘True’ or ‘False’,
          which is used to override default options for this example.
          Any option flags not contained in this dictionary are left at
          their default value (as specified by the *note DocTestRunner:
          424d.’s *note optionflags: f6b.).  By default, no options are
          set.


File: python.info,  Node: DocTestFinder objects,  Next: DocTestParser objects,  Prev: Example Objects,  Up: Advanced API

5.26.4.17 DocTestFinder objects
...............................

 -- Class: doctest.DocTestFinder (verbose=False, parser=DocTestParser(),
          recurse=True, exclude_empty=True)

     A processing class used to extract the *note DocTest: 17c2.s that
     are relevant to a given object, from its docstring and the
     docstrings of its contained objects.  ‘DocTest’s can be extracted
     from modules, classes, functions, methods, staticmethods,
     classmethods, and properties.

     The optional argument 'verbose' can be used to display the objects
     searched by the finder.  It defaults to ‘False’ (no output).

     The optional argument 'parser' specifies the *note DocTestParser:
     423e. object (or a drop-in replacement) that is used to extract
     doctests from docstrings.

     If the optional argument 'recurse' is false, then *note
     DocTestFinder.find(): 180e. will only examine the given object, and
     not any contained objects.

     If the optional argument 'exclude_empty' is false, then *note
     DocTestFinder.find(): 180e. will include tests for objects with
     empty docstrings.

     ‘DocTestFinder’ defines the following method:

      -- Method: find (obj[, name][, module][, globs][, extraglobs])

          Return a list of the *note DocTest: 17c2.s that are defined by
          'obj'’s docstring, or by any of its contained objects’
          docstrings.

          The optional argument 'name' specifies the object’s name; this
          name will be used to construct names for the returned *note
          DocTest: 17c2.s.  If 'name' is not specified, then
          ‘obj.__name__’ is used.

          The optional parameter 'module' is the module that contains
          the given object.  If the module is not specified or is
          ‘None’, then the test finder will attempt to automatically
          determine the correct module.  The object’s module is used:

             * As a default namespace, if 'globs' is not specified.

             * To prevent the DocTestFinder from extracting DocTests
               from objects that are imported from other modules.
               (Contained objects with modules other than 'module' are
               ignored.)

             * To find the name of the file containing the object.

             * To help find the line number of the object within its
               file.

          If 'module' is ‘False’, no attempt to find the module will be
          made.  This is obscure, of use mostly in testing doctest
          itself: if 'module' is ‘False’, or is ‘None’ but cannot be
          found automatically, then all objects are considered to belong
          to the (non-existent) module, so all contained objects will
          (recursively) be searched for doctests.

          The globals for each *note DocTest: 17c2. is formed by
          combining 'globs' and 'extraglobs' (bindings in 'extraglobs'
          override bindings in 'globs').  A new shallow copy of the
          globals dictionary is created for each ‘DocTest’.  If 'globs'
          is not specified, then it defaults to the module’s *note
          __dict__: 20d1, if specified, or ‘{}’ otherwise.  If
          'extraglobs' is not specified, then it defaults to ‘{}’.


File: python.info,  Node: DocTestParser objects,  Next: TestResults objects,  Prev: DocTestFinder objects,  Up: Advanced API

5.26.4.18 DocTestParser objects
...............................

 -- Class: doctest.DocTestParser

     A processing class used to extract interactive examples from a
     string, and use them to create a *note DocTest: 17c2. object.

     ‘DocTestParser’ defines the following methods:

      -- Method: get_doctest (string, globs, name, filename, lineno)

          Extract all doctest examples from the given string, and
          collect them into a *note DocTest: 17c2. object.

          'globs', 'name', 'filename', and 'lineno' are attributes for
          the new ‘DocTest’ object.  See the documentation for *note
          DocTest: 17c2. for more information.

      -- Method: get_examples (string, name='<string>')

          Extract all doctest examples from the given string, and return
          them as a list of *note Example: 4262. objects.  Line numbers
          are 0-based.  The optional argument 'name' is a name
          identifying this string, and is only used for error messages.

      -- Method: parse (string, name='<string>')

          Divide the given string into examples and intervening text,
          and return them as a list of alternating *note Example: 4262.s
          and strings.  Line numbers for the ‘Example’s are 0-based.
          The optional argument 'name' is a name identifying this
          string, and is only used for error messages.


File: python.info,  Node: TestResults objects,  Next: DocTestRunner objects,  Prev: DocTestParser objects,  Up: Advanced API

5.26.4.19 TestResults objects
.............................

 -- Class: doctest.TestResults (failed, attempted)

      -- Attribute: failed

          Number of failed tests.

      -- Attribute: attempted

          Number of attempted tests.

      -- Attribute: skipped

          Number of skipped tests.

          Added in version 3.13.


File: python.info,  Node: DocTestRunner objects,  Next: OutputChecker objects,  Prev: TestResults objects,  Up: Advanced API

5.26.4.20 DocTestRunner objects
...............................

 -- Class: doctest.DocTestRunner (checker=None, verbose=None,
          optionflags=0)

     A processing class used to execute and verify the interactive
     examples in a *note DocTest: 17c2.

     The comparison between expected outputs and actual outputs is done
     by an *note OutputChecker: 424c.  This comparison may be customized
     with a number of option flags; see section *note Option Flags: f6b.
     for more information.  If the option flags are insufficient, then
     the comparison may also be customized by passing a subclass of
     ‘OutputChecker’ to the constructor.

     The test runner’s display output can be controlled in two ways.
     First, an output function can be passed to *note run(): 1dc.; this
     function will be called with strings that should be displayed.  It
     defaults to ‘sys.stdout.write’.  If capturing the output is not
     sufficient, then the display output can be also customized by
     subclassing DocTestRunner, and overriding the methods *note
     report_start(): 427e, *note report_success(): 427f, *note
     report_unexpected_exception(): 4280, and *note report_failure():
     4281.

     The optional keyword argument 'checker' specifies the *note
     OutputChecker: 424c. object (or drop-in replacement) that should be
     used to compare the expected outputs to the actual outputs of
     doctest examples.

     The optional keyword argument 'verbose' controls the
     ‘DocTestRunner’’s verbosity.  If 'verbose' is ‘True’, then
     information is printed about each example, as it is run.  If
     'verbose' is ‘False’, then only failures are printed.  If 'verbose'
     is unspecified, or ‘None’, then verbose output is used iff the
     command-line switch ‘-v’ is used.

     The optional keyword argument 'optionflags' can be used to control
     how the test runner compares expected output to actual output, and
     how it displays failures.  For more information, see section *note
     Option Flags: f6b.

     The test runner accumulates statistics.  The aggregated number of
     attempted, failed and skipped examples is also available via the
     *note tries: 4282, *note failures: 4283. and *note skips: 1dd.
     attributes.  The *note run(): 1dc. and *note summarize(): 4257.
     methods return a *note TestResults: 4279. instance.

     ‘DocTestRunner’ defines the following methods:

      -- Method: report_start (out, test, example)

          Report that the test runner is about to process the given
          example.  This method is provided to allow subclasses of
          ‘DocTestRunner’ to customize their output; it should not be
          called directly.

          'example' is the example about to be processed.  'test' is the
          test containing 'example'.  'out' is the output function that
          was passed to *note DocTestRunner.run(): 1dc.

      -- Method: report_success (out, test, example, got)

          Report that the given example ran successfully.  This method
          is provided to allow subclasses of ‘DocTestRunner’ to
          customize their output; it should not be called directly.

          'example' is the example about to be processed.  'got' is the
          actual output from the example.  'test' is the test containing
          'example'.  'out' is the output function that was passed to
          *note DocTestRunner.run(): 1dc.

      -- Method: report_failure (out, test, example, got)

          Report that the given example failed.  This method is provided
          to allow subclasses of ‘DocTestRunner’ to customize their
          output; it should not be called directly.

          'example' is the example about to be processed.  'got' is the
          actual output from the example.  'test' is the test containing
          'example'.  'out' is the output function that was passed to
          *note DocTestRunner.run(): 1dc.

      -- Method: report_unexpected_exception (out, test, example,
               exc_info)

          Report that the given example raised an unexpected exception.
          This method is provided to allow subclasses of ‘DocTestRunner’
          to customize their output; it should not be called directly.

          'example' is the example about to be processed.  'exc_info' is
          a tuple containing information about the unexpected exception
          (as returned by *note sys.exc_info(): 68d.).  'test' is the
          test containing 'example'.  'out' is the output function that
          was passed to *note DocTestRunner.run(): 1dc.

      -- Method: run (test, compileflags=None, out=None,
               clear_globs=True)

          Run the examples in 'test' (a *note DocTest: 17c2. object),
          and display the results using the writer function 'out'.
          Return a *note TestResults: 4279. instance.

          The examples are run in the namespace ‘test.globs’.  If
          'clear_globs' is true (the default), then this namespace will
          be cleared after the test runs, to help with garbage
          collection.  If you would like to examine the namespace after
          the test completes, then use 'clear_globs=False'.

          'compileflags' gives the set of flags that should be used by
          the Python compiler when running the examples.  If not
          specified, then it will default to the set of future-import
          flags that apply to 'globs'.

          The output of each example is checked using the
          ‘DocTestRunner’’s output checker, and the results are
          formatted by the ‘DocTestRunner.report_*()’ methods.

      -- Method: summarize (verbose=None)

          Print a summary of all the test cases that have been run by
          this DocTestRunner, and return a *note TestResults: 4279.
          instance.

          The optional 'verbose' argument controls how detailed the
          summary is.  If the verbosity is not specified, then the
          ‘DocTestRunner’’s verbosity is used.

     *note DocTestParser: 423e. has the following attributes:

      -- Attribute: tries

          Number of attempted examples.

      -- Attribute: failures

          Number of failed examples.

      -- Attribute: skips

          Number of skipped examples.

          Added in version 3.13.


File: python.info,  Node: OutputChecker objects,  Prev: DocTestRunner objects,  Up: Advanced API

5.26.4.21 OutputChecker objects
...............................

 -- Class: doctest.OutputChecker

     A class used to check the whether the actual output from a doctest
     example matches the expected output.  ‘OutputChecker’ defines two
     methods: *note check_output(): 4286, which compares a given pair of
     outputs, and returns ‘True’ if they match; and *note
     output_difference(): 4287, which returns a string describing the
     differences between two outputs.

     ‘OutputChecker’ defines the following methods:

      -- Method: check_output (want, got, optionflags)

          Return ‘True’ iff the actual output from an example ('got')
          matches the expected output ('want').  These strings are
          always considered to match if they are identical; but
          depending on what option flags the test runner is using,
          several non-exact match types are also possible.  See section
          *note Option Flags: f6b. for more information about option
          flags.

      -- Method: output_difference (example, got, optionflags)

          Return a string describing the differences between the
          expected output for a given example ('example') and the actual
          output ('got').  'optionflags' is the set of option flags used
          to compare 'want' and 'got'.


File: python.info,  Node: Debugging,  Next: Soapbox,  Prev: Advanced API,  Up: doctest — Test interactive Python examples

5.26.4.22 Debugging
...................

Doctest provides several mechanisms for debugging doctest examples:

   * Several functions convert doctests to executable Python programs,
     which can be run under the Python debugger, *note pdb: a5.

   * The *note DebugRunner: 428a. class is a subclass of *note
     DocTestRunner: 424d. that raises an exception for the first failing
     example, containing information about that example.  This
     information can be used to perform post-mortem debugging on the
     example.

   * The *note unittest: 106. cases generated by *note DocTestSuite():
     e25. support the *note debug(): 428b. method defined by *note
     unittest.TestCase: 451.

   * You can add a call to *note pdb.set_trace(): 235. in a doctest
     example, and you’ll drop into the Python debugger when that line is
     executed.  Then you can inspect current values of variables, and so
     on.  For example, suppose ‘a.py’ contains just this module
     docstring:

          """
          >>> def f(x):
          ...     g(x*2)
          >>> def g(x):
          ...     print(x+3)
          ...     import pdb; pdb.set_trace()
          >>> f(3)
          9
          """

     Then an interactive Python session may look like this:

          >>> import a, doctest
          >>> doctest.testmod(a)
          --Return--
          > <doctest a[1]>(3)g()->None
          -> import pdb; pdb.set_trace()
          (Pdb) list
            1     def g(x):
            2         print(x+3)
            3  ->     import pdb; pdb.set_trace()
          [EOF]
          (Pdb) p x
          6
          (Pdb) step
          --Return--
          > <doctest a[0]>(2)f()->None
          -> g(x*2)
          (Pdb) list
            1     def f(x):
            2  ->     g(x*2)
          [EOF]
          (Pdb) p x
          3
          (Pdb) step
          --Return--
          > <doctest a[2]>(1)?()->None
          -> f(3)
          (Pdb) cont
          (0, 3)
          >>>

Functions that convert doctests to Python code, and possibly run the
synthesized code under the debugger:

 -- Function: doctest.script_from_examples (s)

     Convert text with examples to a script.

     Argument 's' is a string containing doctest examples.  The string
     is converted to a Python script, where doctest examples in 's' are
     converted to regular code, and everything else is converted to
     Python comments.  The generated script is returned as a string.
     For example,

          import doctest
          print(doctest.script_from_examples(r"""
              Set x and y to 1 and 2.
              >>> x, y = 1, 2

              Print their sum:
              >>> print(x+y)
              3
          """))

     displays:

          # Set x and y to 1 and 2.
          x, y = 1, 2
          #
          # Print their sum:
          print(x+y)
          # Expected:
          ## 3

     This function is used internally by other functions (see below),
     but can also be useful when you want to transform an interactive
     Python session into a Python script.

 -- Function: doctest.testsource (module, name)

     Convert the doctest for an object to a script.

     Argument 'module' is a module object, or dotted name of a module,
     containing the object whose doctests are of interest.  Argument
     'name' is the name (within the module) of the object with the
     doctests of interest.  The result is a string, containing the
     object’s docstring converted to a Python script, as described for
     *note script_from_examples(): 428c. above.  For example, if module
     ‘a.py’ contains a top-level function ‘f()’, then

          import a, doctest
          print(doctest.testsource(a, "a.f"))

     prints a script version of function ‘f()’’s docstring, with
     doctests converted to code, and the rest placed in comments.

 -- Function: doctest.debug (module, name, pm=False)

     Debug the doctests for an object.

     The 'module' and 'name' arguments are the same as for function
     *note testsource(): 428d. above.  The synthesized Python script for
     the named object’s docstring is written to a temporary file, and
     then that file is run under the control of the Python debugger,
     *note pdb: a5.

     A shallow copy of ‘module.__dict__’ is used for both local and
     global execution context.

     Optional argument 'pm' controls whether post-mortem debugging is
     used.  If 'pm' has a true value, the script file is run directly,
     and the debugger gets involved only if the script terminates via
     raising an unhandled exception.  If it does, then post-mortem
     debugging is invoked, via *note pdb.post_mortem(): 1428, passing
     the traceback object from the unhandled exception.  If 'pm' is not
     specified, or is false, the script is run under the debugger from
     the start, via passing an appropriate *note exec(): 17f. call to
     *note pdb.run(): 428e.

 -- Function: doctest.debug_src (src, pm=False, globs=None)

     Debug the doctests in a string.

     This is like function *note debug(): 428b. above, except that a
     string containing doctest examples is specified directly, via the
     'src' argument.

     Optional argument 'pm' has the same meaning as in function *note
     debug(): 428b. above.

     Optional argument 'globs' gives a dictionary to use as both local
     and global execution context.  If not specified, or ‘None’, an
     empty dictionary is used.  If specified, a shallow copy of the
     dictionary is used.

The *note DebugRunner: 428a. class, and the special exceptions it may
raise, are of most interest to testing framework authors, and will only
be sketched here.  See the source code, and especially ‘DebugRunner’’s
docstring (which is a doctest!)  for more details:

 -- Class: doctest.DebugRunner (checker=None, verbose=None,
          optionflags=0)

     A subclass of *note DocTestRunner: 424d. that raises an exception
     as soon as a failure is encountered.  If an unexpected exception
     occurs, an *note UnexpectedException: 4290. exception is raised,
     containing the test, the example, and the original exception.  If
     the output doesn’t match, then a *note DocTestFailure: 4291.
     exception is raised, containing the test, the example, and the
     actual output.

     For information about the constructor parameters and methods, see
     the documentation for *note DocTestRunner: 424d. in section *note
     Advanced API: 4261.

There are two exceptions that may be raised by *note DebugRunner: 428a.
instances:

 -- Exception: doctest.DocTestFailure (test, example, got)

     An exception raised by *note DocTestRunner: 424d. to signal that a
     doctest example’s actual output did not match its expected output.
     The constructor arguments are used to initialize the attributes of
     the same names.

*note DocTestFailure: 4291. defines the following attributes:

 -- Attribute: DocTestFailure.test

     The *note DocTest: 17c2. object that was being run when the example
     failed.

 -- Attribute: DocTestFailure.example

     The *note Example: 4262. that failed.

 -- Attribute: DocTestFailure.got

     The example’s actual output.

 -- Exception: doctest.UnexpectedException (test, example, exc_info)

     An exception raised by *note DocTestRunner: 424d. to signal that a
     doctest example raised an unexpected exception.  The constructor
     arguments are used to initialize the attributes of the same names.

*note UnexpectedException: 4290. defines the following attributes:

 -- Attribute: UnexpectedException.test

     The *note DocTest: 17c2. object that was being run when the example
     failed.

 -- Attribute: UnexpectedException.example

     The *note Example: 4262. that failed.

 -- Attribute: UnexpectedException.exc_info

     A tuple containing information about the unexpected exception, as
     returned by *note sys.exc_info(): 68d.


File: python.info,  Node: Soapbox,  Prev: Debugging,  Up: doctest — Test interactive Python examples

5.26.4.23 Soapbox
.................

As mentioned in the introduction, ‘doctest’ has grown to have three
primary uses:

  1. Checking examples in docstrings.

  2. Regression testing.

  3. Executable documentation / literate testing.

These uses have different requirements, and it is important to
distinguish them.  In particular, filling your docstrings with obscure
test cases makes for bad documentation.

When writing a docstring, choose docstring examples with care.  There’s
an art to this that needs to be learned—it may not be natural at first.
Examples should add genuine value to the documentation.  A good example
can often be worth many words.  If done with care, the examples will be
invaluable for your users, and will pay back the time it takes to
collect them many times over as the years go by and things change.  I’m
still amazed at how often one of my ‘doctest’ examples stops working
after a “harmless” change.

Doctest also makes an excellent tool for regression testing, especially
if you don’t skimp on explanatory text.  By interleaving prose and
examples, it becomes much easier to keep track of what’s actually being
tested, and why.  When a test fails, good prose can make it much easier
to figure out what the problem is, and how it should be fixed.  It’s
true that you could write extensive comments in code-based testing, but
few programmers do.  Many have found that using doctest approaches
instead leads to much clearer tests.  Perhaps this is simply because
doctest makes writing prose a little easier than writing code, while
writing comments in code is a little harder.  I think it goes deeper
than just that: the natural attitude when writing a doctest-based test
is that you want to explain the fine points of your software, and
illustrate them with examples.  This in turn naturally leads to test
files that start with the simplest features, and logically progress to
complications and edge cases.  A coherent narrative is the result,
instead of a collection of isolated functions that test isolated bits of
functionality seemingly at random.  It’s a different attitude, and
produces different results, blurring the distinction between testing and
explaining.

Regression testing is best confined to dedicated objects or files.
There are several options for organizing tests:

   * Write text files containing test cases as interactive examples, and
     test the files using *note testfile(): 422d. or *note
     DocFileSuite(): 425c.  This is recommended, although is easiest to
     do for new projects, designed from the start to use doctest.

   * Define functions named ‘_regrtest_topic’ that consist of single
     docstrings, containing test cases for the named topics.  These
     functions can be included in the same file as the module, or
     separated out into a separate test file.

   * Define a *note __test__: 4239. dictionary mapping from regression
     test topics to docstrings containing test cases.

When you have placed your tests in a module, the module can itself be
the test runner.  When a test fails, you can arrange for your test
runner to re-run only the failing doctest while you debug the problem.
Here is a minimal example of such a test runner:

     if __name__ == '__main__':
         import doctest
         flags = doctest.REPORT_NDIFF|doctest.FAIL_FAST
         if len(sys.argv) > 1:
             name = sys.argv[1]
             if name in globals():
                 obj = globals()[name]
             else:
                 obj = __test__[name]
             doctest.run_docstring_examples(obj, globals(), name=name,
                                            optionflags=flags)
         else:
             fail, total = doctest.testmod(optionflags=flags)
             print(f"{fail} failures out of {total} tests")


File: python.info,  Node: unittest — Unit testing framework,  Next: unittest mock — mock object library,  Prev: doctest — Test interactive Python examples,  Up: Development Tools

5.26.5 ‘unittest’ — Unit testing framework
------------------------------------------

'Source code:' Lib/unittest/__init__.py(1)

__________________________________________________________________

(If you are already familiar with the basic concepts of testing, you
might want to skip to *note the list of assert methods: 429d.)

The ‘unittest’ unit testing framework was originally inspired by JUnit
and has a similar flavor as major unit testing frameworks in other
languages.  It supports test automation, sharing of setup and shutdown
code for tests, aggregation of tests into collections, and independence
of the tests from the reporting framework.

To achieve this, ‘unittest’ supports some important concepts in an
object-oriented way:

test fixture

     A 'test fixture' represents the preparation needed to perform one
     or more tests, and any associated cleanup actions.  This may
     involve, for example, creating temporary or proxy databases,
     directories, or starting a server process.

test case

     A 'test case' is the individual unit of testing.  It checks for a
     specific response to a particular set of inputs.  ‘unittest’
     provides a base class, *note TestCase: 451, which may be used to
     create new test cases.

test suite

     A 'test suite' is a collection of test cases, test suites, or both.
     It is used to aggregate tests that should be executed together.

test runner

     A 'test runner' is a component which orchestrates the execution of
     tests and provides the outcome to the user.  The runner may use a
     graphical interface, a textual interface, or return a special value
     to indicate the results of executing the tests.

See also
........

Module *note doctest: 3a.

     Another test-support module with a very different flavor.

Simple Smalltalk Testing: With Patterns(2)

     Kent Beck’s original paper on testing frameworks using the pattern
     shared by ‘unittest’.

pytest(3)

     Third-party unittest framework with a lighter-weight syntax for
     writing tests.  For example, ‘assert func(10) == 42’.

The Python Testing Tools Taxonomy(4)

     An extensive list of Python testing tools including functional
     testing frameworks and mock object libraries.

Testing in Python Mailing List(5)

     A special-interest-group for discussion of testing, and testing
     tools, in Python.

The script ‘Tools/unittestgui/unittestgui.py’ in the Python source
distribution is a GUI tool for test discovery and execution.  This is
intended largely for ease of use for those new to unit testing.  For
production environments it is recommended that tests be driven by a
continuous integration system such as Buildbot(6), Jenkins(7), GitHub
Actions(8), or AppVeyor(9).

* Menu:

* Basic example::
* Command-Line Interface: Command-Line Interface<2>.
* Test Discovery::
* Organizing test code::
* Re-using old test code::
* Skipping tests and expected failures::
* Distinguishing test iterations using subtests::
* Classes and functions::
* Class and Module Fixtures::
* Signal Handling::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/unittest/__init__.py

   (2) 
https://web.archive.org/web/20150315073817/http://www.xprogramming.com/testfram.htm

   (3) https://docs.pytest.org/

   (4) https://wiki.python.org/moin/PythonTestingToolsTaxonomy

   (5) http://lists.idyll.org/listinfo/testing-in-python

   (6) https://buildbot.net/

   (7) https://www.jenkins.io/

   (8) https://github.com/features/actions

   (9) https://www.appveyor.com/


File: python.info,  Node: Basic example,  Next: Command-Line Interface<2>,  Up: unittest — Unit testing framework

5.26.5.1 Basic example
......................

The ‘unittest’ module provides a rich set of tools for constructing and
running tests.  This section demonstrates that a small subset of the
tools suffice to meet the needs of most users.

Here is a short script to test three string methods:

     import unittest

     class TestStringMethods(unittest.TestCase):

         def test_upper(self):
             self.assertEqual('foo'.upper(), 'FOO')

         def test_isupper(self):
             self.assertTrue('FOO'.isupper())
             self.assertFalse('Foo'.isupper())

         def test_split(self):
             s = 'hello world'
             self.assertEqual(s.split(), ['hello', 'world'])
             # check that s.split fails when the separator is not a string
             with self.assertRaises(TypeError):
                 s.split(2)

     if __name__ == '__main__':
         unittest.main()

A test case is created by subclassing *note unittest.TestCase: 451.  The
three individual tests are defined with methods whose names start with
the letters ‘test’.  This naming convention informs the test runner
about which methods represent tests.

The crux of each test is a call to *note assertEqual(): 52c. to check
for an expected result; *note assertTrue(): 52a. or *note assertFalse():
52b. to verify a condition; or *note assertRaises(): 530. to verify that
a specific exception gets raised.  These methods are used instead of the
*note assert: 972. statement so the test runner can accumulate all test
results and produce a report.

The *note setUp(): 1384. and *note tearDown(): 1385. methods allow you
to define instructions that will be executed before and after each test
method.  They are covered in more detail in the section *note Organizing
test code: 42a0.

The final block shows a simple way to run the tests.  *note
unittest.main(): 101e. provides a command-line interface to the test
script.  When run from the command line, the above script produces an
output that looks like this:

     ...
     ----------------------------------------------------------------------
     Ran 3 tests in 0.000s

     OK

Passing the ‘-v’ option to your test script will instruct *note
unittest.main(): 101e. to enable a higher level of verbosity, and
produce the following output:

     test_isupper (__main__.TestStringMethods.test_isupper) ... ok
     test_split (__main__.TestStringMethods.test_split) ... ok
     test_upper (__main__.TestStringMethods.test_upper) ... ok

     ----------------------------------------------------------------------
     Ran 3 tests in 0.001s

     OK

The above examples show the most commonly used ‘unittest’ features which
are sufficient to meet many everyday testing needs.  The remainder of
the documentation explores the full feature set from first principles.

Changed in version 3.11: The behavior of returning a value from a test
method (other than the default ‘None’ value), is now deprecated.


File: python.info,  Node: Command-Line Interface<2>,  Next: Test Discovery,  Prev: Basic example,  Up: unittest — Unit testing framework

5.26.5.2 Command-Line Interface
...............................

The unittest module can be used from the command line to run tests from
modules, classes or even individual test methods:

     python -m unittest test_module1 test_module2
     python -m unittest test_module.TestClass
     python -m unittest test_module.TestClass.test_method

You can pass in a list with any combination of module names, and fully
qualified class or method names.

Test modules can be specified by file path as well:

     python -m unittest tests/test_something.py

This allows you to use the shell filename completion to specify the test
module.  The file specified must still be importable as a module.  The
path is converted to a module name by removing the ‘.py’ and converting
path separators into ‘.’.  If you want to execute a test file that isn’t
importable as a module you should execute the file directly instead.

You can run tests with more detail (higher verbosity) by passing in the
-v flag:

     python -m unittest -v test_module

When executed without arguments *note Test Discovery: 42a3. is started:

     python -m unittest

For a list of all the command-line options:

     python -m unittest -h

Changed in version 3.2: In earlier versions it was only possible to run
individual test methods and not modules or classes.

* Menu:

* Command-line options: Command-line options<4>.


File: python.info,  Node: Command-line options<4>,  Up: Command-Line Interface<2>

5.26.5.3 Command-line options
.............................

‘unittest’ supports these command-line options:

 -- Option: -b, --buffer

     The standard output and standard error streams are buffered during
     the test run.  Output during a passing test is discarded.  Output
     is echoed normally on test fail or error and is added to the
     failure messages.

 -- Option: -c, --catch

     ‘Control’-‘C’ during the test run waits for the current test to end
     and then reports all the results so far.  A second ‘Control’-‘C’
     raises the normal *note KeyboardInterrupt: 9dc. exception.

     See *note Signal Handling: 42a7. for the functions that provide
     this functionality.

 -- Option: -f, --failfast

     Stop the test run on the first error or failure.

 -- Option: -k

     Only run test methods and classes that match the pattern or
     substring.  This option may be used multiple times, in which case
     all test cases that match any of the given patterns are included.

     Patterns that contain a wildcard character (‘*’) are matched
     against the test name using *note fnmatch.fnmatchcase(): 19fb.;
     otherwise simple case-sensitive substring matching is used.

     Patterns are matched against the fully qualified test method name
     as imported by the test loader.

     For example, ‘-k foo’ matches ‘foo_tests.SomeTest.test_something’,
     ‘bar_tests.SomeTest.test_foo’, but not
     ‘bar_tests.FooTest.test_something’.

 -- Option: --locals

     Show local variables in tracebacks.

 -- Option: --durations N

     Show the N slowest test cases (N=0 for all).

Added in version 3.2: The command-line options ‘-b’, ‘-c’ and ‘-f’ were
added.

Added in version 3.5: The command-line option ‘--locals’.

Added in version 3.7: The command-line option ‘-k’.

Added in version 3.12: The command-line option ‘--durations’.

The command line can also be used for test discovery, for running all of
the tests in a project or just a subset.


File: python.info,  Node: Test Discovery,  Next: Organizing test code,  Prev: Command-Line Interface<2>,  Up: unittest — Unit testing framework

5.26.5.4 Test Discovery
.......................

Added in version 3.2.

Unittest supports simple test discovery.  In order to be compatible with
test discovery, all of the test files must be *note modules: 1df4. or
*note packages: 1e05. importable from the top-level directory of the
project (this means that their filenames must be valid *note
identifiers: 2040.).

Test discovery is implemented in *note TestLoader.discover(): 1020, but
can also be used from the command line.  The basic command-line usage
is:

     cd project_directory
     python -m unittest discover

     Note: As a shortcut, ‘python -m unittest’ is the equivalent of
     ‘python -m unittest discover’.  If you want to pass arguments to
     test discovery the ‘discover’ sub-command must be used explicitly.

The ‘discover’ sub-command has the following options:

 -- Option: -v, --verbose

     Verbose output

 -- Option: -s, --start-directory directory

     Directory to start discovery (‘.’ default)

 -- Option: -p, --pattern pattern

     Pattern to match test files (‘test*.py’ default)

 -- Option: -t, --top-level-directory directory

     Top level directory of project (defaults to start directory)

The *note -s: 42af, *note -p: 42b1, and *note -t: 42b3. options can be
passed in as positional arguments in that order.  The following two
command lines are equivalent:

     python -m unittest discover -s project_directory -p "*_test.py"
     python -m unittest discover project_directory "*_test.py"

As well as being a path it is possible to pass a package name, for
example ‘myproject.subpackage.test’, as the start directory.  The
package name you supply will then be imported and its location on the
filesystem will be used as the start directory.

     Caution: Test discovery loads tests by importing them.  Once test
     discovery has found all the test files from the start directory you
     specify it turns the paths into package names to import.  For
     example ‘foo/bar/baz.py’ will be imported as ‘foo.bar.baz’.

     If you have a package installed globally and attempt test discovery
     on a different copy of the package then the import 'could' happen
     from the wrong place.  If this happens test discovery will warn you
     and exit.

     If you supply the start directory as a package name rather than a
     path to a directory then discover assumes that whichever location
     it imports from is the location you intended, so you will not get
     the warning.

Test modules and packages can customize test loading and discovery by
through the *note load_tests protocol: 42b5.

Changed in version 3.4: Test discovery supports *note namespace
packages: 1e06. for the start directory.  Note that you need to specify
the top level directory too (e.g.  ‘python -m unittest discover -s
root/namespace -t root’).

Changed in version 3.11: ‘unittest’ dropped the *note namespace
packages: 1e06. support in Python 3.11.  It has been broken since Python
3.7.  Start directory and subdirectories containing tests must be
regular package that have ‘__init__.py’ file.

Directories containing start directory still can be a namespace package.
In this case, you need to specify start directory as dotted package
name, and target directory explicitly.  For example:

     # proj/  <-- current directory
     #   namespace/
     #     mypkg/
     #       __init__.py
     #       test_mypkg.py

     python -m unittest discover -s namespace.mypkg -t .


File: python.info,  Node: Organizing test code,  Next: Re-using old test code,  Prev: Test Discovery,  Up: unittest — Unit testing framework

5.26.5.5 Organizing test code
.............................

The basic building blocks of unit testing are 'test cases' — single
scenarios that must be set up and checked for correctness.  In
‘unittest’, test cases are represented by *note unittest.TestCase: 451.
instances.  To make your own test cases you must write subclasses of
*note TestCase: 451. or use *note FunctionTestCase: 1818.

The testing code of a *note TestCase: 451. instance should be entirely
self contained, such that it can be run either in isolation or in
arbitrary combination with any number of other test cases.

The simplest *note TestCase: 451. subclass will simply implement a test
method (i.e.  a method whose name starts with ‘test’) in order to
perform specific testing code:

     import unittest

     class DefaultWidgetSizeTestCase(unittest.TestCase):
         def test_default_widget_size(self):
             widget = Widget('The widget')
             self.assertEqual(widget.size(), (50, 50))

Note that in order to test something, we use one of the *note assert*
methods: 429d. provided by the *note TestCase: 451. base class.  If the
test fails, an exception will be raised with an explanatory message, and
‘unittest’ will identify the test case as a 'failure'.  Any other
exceptions will be treated as 'errors'.

Tests can be numerous, and their set-up can be repetitive.  Luckily, we
can factor out set-up code by implementing a method called *note
setUp(): 1384, which the testing framework will automatically call for
every single test we run:

     import unittest

     class WidgetTestCase(unittest.TestCase):
         def setUp(self):
             self.widget = Widget('The widget')

         def test_default_widget_size(self):
             self.assertEqual(self.widget.size(), (50,50),
                              'incorrect default size')

         def test_widget_resize(self):
             self.widget.resize(100,150)
             self.assertEqual(self.widget.size(), (100,150),
                              'wrong size after resize')

     Note: The order in which the various tests will be run is
     determined by sorting the test method names with respect to the
     built-in ordering for strings.

If the *note setUp(): 1384. method raises an exception while the test is
running, the framework will consider the test to have suffered an error,
and the test method will not be executed.

Similarly, we can provide a *note tearDown(): 1385. method that tidies
up after the test method has been run:

     import unittest

     class WidgetTestCase(unittest.TestCase):
         def setUp(self):
             self.widget = Widget('The widget')

         def tearDown(self):
             self.widget.dispose()

If *note setUp(): 1384. succeeded, *note tearDown(): 1385. will be run
whether the test method succeeded or not.

Such a working environment for the testing code is called a 'test
fixture'.  A new TestCase instance is created as a unique test fixture
used to execute each individual test method.  Thus *note setUp(): 1384,
*note tearDown(): 1385, and ‘TestCase.__init__()’ will be called once
per test.

It is recommended that you use TestCase implementations to group tests
together according to the features they test.  ‘unittest’ provides a
mechanism for this: the 'test suite', represented by ‘unittest’’s *note
TestSuite: e26. class.  In most cases, calling *note unittest.main():
101e. will do the right thing and collect all the module’s test cases
for you and execute them.

However, should you want to customize the building of your test suite,
you can do it yourself:

     def suite():
         suite = unittest.TestSuite()
         suite.addTest(WidgetTestCase('test_default_widget_size'))
         suite.addTest(WidgetTestCase('test_widget_resize'))
         return suite

     if __name__ == '__main__':
         runner = unittest.TextTestRunner()
         runner.run(suite())

You can place the definitions of test cases and test suites in the same
modules as the code they are to test (such as ‘widget.py’), but there
are several advantages to placing the test code in a separate module,
such as ‘test_widget.py’:

   * The test module can be run standalone from the command line.

   * The test code can more easily be separated from shipped code.

   * There is less temptation to change test code to fit the code it
     tests without a good reason.

   * Test code should be modified much less frequently than the code it
     tests.

   * Tested code can be refactored more easily.

   * Tests for modules written in C must be in separate modules anyway,
     so why not be consistent?

   * If the testing strategy changes, there is no need to change the
     source code.


File: python.info,  Node: Re-using old test code,  Next: Skipping tests and expected failures,  Prev: Organizing test code,  Up: unittest — Unit testing framework

5.26.5.6 Re-using old test code
...............................

Some users will find that they have existing test code that they would
like to run from ‘unittest’, without converting every old test function
to a *note TestCase: 451. subclass.

For this reason, ‘unittest’ provides a *note FunctionTestCase: 1818.
class.  This subclass of *note TestCase: 451. can be used to wrap an
existing test function.  Set-up and tear-down functions can also be
provided.

Given the following test function:

     def testSomething():
         something = makeSomething()
         assert something.name is not None
         # ...

one can create an equivalent test case instance as follows, with
optional set-up and tear-down methods:

     testcase = unittest.FunctionTestCase(testSomething,
                                          setUp=makeSomethingDB,
                                          tearDown=deleteSomethingDB)

     Note: Even though *note FunctionTestCase: 1818. can be used to
     quickly convert an existing test base over to a ‘unittest’-based
     system, this approach is not recommended.  Taking the time to set
     up proper *note TestCase: 451. subclasses will make future test
     refactorings infinitely easier.

In some cases, the existing tests may have been written using the *note
doctest: 3a. module.  If so, ‘doctest’ provides a *note DocTestSuite:
e25. class that can automatically build *note unittest.TestSuite: e26.
instances from the existing ‘doctest’-based tests.


File: python.info,  Node: Skipping tests and expected failures,  Next: Distinguishing test iterations using subtests,  Prev: Re-using old test code,  Up: unittest — Unit testing framework

5.26.5.7 Skipping tests and expected failures
.............................................

Added in version 3.1.

Unittest supports skipping individual test methods and even whole
classes of tests.  In addition, it supports marking a test as an
“expected failure,” a test that is broken and will fail, but shouldn’t
be counted as a failure on a *note TestResult: 11ab.

Skipping a test is simply a matter of using the *note skip(): 1b69.
*note decorator: 734. or one of its conditional variants, calling *note
TestCase.skipTest(): 42bb. within a *note setUp(): 1384. or test method,
or raising *note SkipTest: 101f. directly.

Basic skipping looks like this:

     class MyTestCase(unittest.TestCase):

         @unittest.skip("demonstrating skipping")
         def test_nothing(self):
             self.fail("shouldn't happen")

         @unittest.skipIf(mylib.__version__ < (1, 3),
                          "not supported in this library version")
         def test_format(self):
             # Tests that work for only a certain version of the library.
             pass

         @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
         def test_windows_support(self):
             # windows specific testing code
             pass

         def test_maybe_skipped(self):
             if not external_resource_available():
                 self.skipTest("external resource not available")
             # test code that depends on the external resource
             pass

This is the output of running the example above in verbose mode:

     test_format (__main__.MyTestCase.test_format) ... skipped 'not supported in this library version'
     test_nothing (__main__.MyTestCase.test_nothing) ... skipped 'demonstrating skipping'
     test_maybe_skipped (__main__.MyTestCase.test_maybe_skipped) ... skipped 'external resource not available'
     test_windows_support (__main__.MyTestCase.test_windows_support) ... skipped 'requires Windows'

     ----------------------------------------------------------------------
     Ran 4 tests in 0.005s

     OK (skipped=4)

Classes can be skipped just like methods:

     @unittest.skip("showing class skipping")
     class MySkippedTestCase(unittest.TestCase):
         def test_not_run(self):
             pass

*note TestCase.setUp(): 1384. can also skip the test.  This is useful
when a resource that needs to be set up is not available.

Expected failures use the *note expectedFailure(): 42bc. decorator.

     class ExpectedFailureTestCase(unittest.TestCase):
         @unittest.expectedFailure
         def test_fail(self):
             self.assertEqual(1, 0, "broken")

It’s easy to roll your own skipping decorators by making a decorator
that calls *note skip(): 1b69. on the test when it wants it to be
skipped.  This decorator skips the test unless the passed object has a
certain attribute:

     def skipUnlessHasattr(obj, attr):
         if hasattr(obj, attr):
             return lambda func: func
         return unittest.skip("{!r} doesn't have {!r}".format(obj, attr))

The following decorators and exception implement test skipping and
expected failures:

 -- Function: @unittest.skip (reason)

     Unconditionally skip the decorated test.  'reason' should describe
     why the test is being skipped.

 -- Function: @unittest.skipIf (condition, reason)

     Skip the decorated test if 'condition' is true.

 -- Function: @unittest.skipUnless (condition, reason)

     Skip the decorated test unless 'condition' is true.

 -- Function: @unittest.expectedFailure

     Mark the test as an expected failure or error.  If the test fails
     or errors in the test function itself (rather than in one of the
     'test fixture' methods) then it will be considered a success.  If
     the test passes, it will be considered a failure.

 -- Exception: unittest.SkipTest (reason)

     This exception is raised to skip a test.

     Usually you can use *note TestCase.skipTest(): 42bb. or one of the
     skipping decorators instead of raising this directly.

Skipped tests will not have *note setUp(): 1384. or *note tearDown():
1385. run around them.  Skipped classes will not have *note
setUpClass(): a5c. or *note tearDownClass(): 1382. run.  Skipped modules
will not have *note setUpModule(): a5b. or *note tearDownModule(): 1381.
run.


File: python.info,  Node: Distinguishing test iterations using subtests,  Next: Classes and functions,  Prev: Skipping tests and expected failures,  Up: unittest — Unit testing framework

5.26.5.8 Distinguishing test iterations using subtests
......................................................

Added in version 3.4.

When there are very small differences among your tests, for instance
some parameters, unittest allows you to distinguish them inside the body
of a test method using the *note subTest(): 101c. context manager.

For example, the following test:

     class NumbersTest(unittest.TestCase):

         def test_even(self):
             """
             Test that numbers between 0 and 5 are all even.
             """
             for i in range(0, 6):
                 with self.subTest(i=i):
                     self.assertEqual(i % 2, 0)

will produce the following output:

     ======================================================================
     FAIL: test_even (__main__.NumbersTest.test_even) (i=1)
     Test that numbers between 0 and 5 are all even.
     ----------------------------------------------------------------------
     Traceback (most recent call last):
       File "subtests.py", line 11, in test_even
         self.assertEqual(i % 2, 0)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^
     AssertionError: 1 != 0

     ======================================================================
     FAIL: test_even (__main__.NumbersTest.test_even) (i=3)
     Test that numbers between 0 and 5 are all even.
     ----------------------------------------------------------------------
     Traceback (most recent call last):
       File "subtests.py", line 11, in test_even
         self.assertEqual(i % 2, 0)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^
     AssertionError: 1 != 0

     ======================================================================
     FAIL: test_even (__main__.NumbersTest.test_even) (i=5)
     Test that numbers between 0 and 5 are all even.
     ----------------------------------------------------------------------
     Traceback (most recent call last):
       File "subtests.py", line 11, in test_even
         self.assertEqual(i % 2, 0)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^
     AssertionError: 1 != 0

Without using a subtest, execution would stop after the first failure,
and the error would be less easy to diagnose because the value of ‘i’
wouldn’t be displayed:

     ======================================================================
     FAIL: test_even (__main__.NumbersTest.test_even)
     ----------------------------------------------------------------------
     Traceback (most recent call last):
       File "subtests.py", line 32, in test_even
         self.assertEqual(i % 2, 0)
     AssertionError: 1 != 0


File: python.info,  Node: Classes and functions,  Next: Class and Module Fixtures,  Prev: Distinguishing test iterations using subtests,  Up: unittest — Unit testing framework

5.26.5.9 Classes and functions
..............................

This section describes in depth the API of ‘unittest’.

* Menu:

* Test cases::
* Grouping tests::
* Loading and running tests::


File: python.info,  Node: Test cases,  Next: Grouping tests,  Up: Classes and functions

5.26.5.10 Test cases
....................

 -- Class: unittest.TestCase (methodName='runTest')

     Instances of the ‘TestCase’ class represent the logical test units
     in the ‘unittest’ universe.  This class is intended to be used as a
     base class, with specific tests being implemented by concrete
     subclasses.  This class implements the interface needed by the test
     runner to allow it to drive the tests, and methods that the test
     code can use to check for and report various kinds of failure.

     Each instance of ‘TestCase’ will run a single base method: the
     method named 'methodName'.  In most uses of ‘TestCase’, you will
     neither change the 'methodName' nor reimplement the default
     ‘runTest()’ method.

     Changed in version 3.2: ‘TestCase’ can be instantiated successfully
     without providing a 'methodName'.  This makes it easier to
     experiment with ‘TestCase’ from the interactive interpreter.

     ‘TestCase’ instances provide three groups of methods: one group
     used to run the test, another used by the test implementation to
     check conditions and report failures, and some inquiry methods
     allowing information about the test itself to be gathered.

     Methods in the first group (running the test) are:

      -- Method: setUp ()

          Method called to prepare the test fixture.  This is called
          immediately before calling the test method; other than *note
          AssertionError: 6ac. or *note SkipTest: 101f, any exception
          raised by this method will be considered an error rather than
          a test failure.  The default implementation does nothing.

      -- Method: tearDown ()

          Method called immediately after the test method has been
          called and the result recorded.  This is called even if the
          test method raised an exception, so the implementation in
          subclasses may need to be particularly careful about checking
          internal state.  Any exception, other than *note
          AssertionError: 6ac. or *note SkipTest: 101f, raised by this
          method will be considered an additional error rather than a
          test failure (thus increasing the total number of reported
          errors).  This method will only be called if the *note
          setUp(): 1384. succeeds, regardless of the outcome of the test
          method.  The default implementation does nothing.

      -- Method: setUpClass ()

          A class method called before tests in an individual class are
          run.  ‘setUpClass’ is called with the class as the only
          argument and must be decorated as a *note classmethod(): 166.:

               @classmethod
               def setUpClass(cls):
                   ...

          See *note Class and Module Fixtures: 42c4. for more details.

          Added in version 3.2.

      -- Method: tearDownClass ()

          A class method called after tests in an individual class have
          run.  ‘tearDownClass’ is called with the class as the only
          argument and must be decorated as a *note classmethod(): 166.:

               @classmethod
               def tearDownClass(cls):
                   ...

          See *note Class and Module Fixtures: 42c4. for more details.

          Added in version 3.2.

      -- Method: run (result=None)

          Run the test, collecting the result into the *note TestResult:
          11ab. object passed as 'result'.  If 'result' is omitted or
          ‘None’, a temporary result object is created (by calling the
          *note defaultTestResult(): 42c5. method) and used.  The result
          object is returned to ‘run()’’s caller.

          The same effect may be had by simply calling the ‘TestCase’
          instance.

          Changed in version 3.3: Previous versions of ‘run’ did not
          return the result.  Neither did calling an instance.

      -- Method: skipTest (reason)

          Calling this during a test method or *note setUp(): 1384.
          skips the current test.  See *note Skipping tests and expected
          failures: 42ba. for more information.

          Added in version 3.1.

      -- Method: subTest (msg=None, **params)

          Return a context manager which executes the enclosed code
          block as a subtest.  'msg' and 'params' are optional,
          arbitrary values which are displayed whenever a subtest fails,
          allowing you to identify them clearly.

          A test case can contain any number of subtest declarations,
          and they can be arbitrarily nested.

          See *note Distinguishing test iterations using subtests: 101d.
          for more information.

          Added in version 3.4.

      -- Method: debug ()

          Run the test without collecting the result.  This allows
          exceptions raised by the test to be propagated to the caller,
          and can be used to support running tests under a debugger.
     The ‘TestCase’ class provides several assert methods to check for
     and report failures.  The following table lists the most commonly
     used methods (see the tables below for more assert methods):

     Method                                        Checks that                       New in
                                                                                     
     ----------------------------------------------------------------------------------------------------
                                                                                     
     *note assertEqual(a, b): 52c.                 ‘a == b’
                                                   
                                                                                     
     *note assertNotEqual(a, b): 52d.              ‘a != b’
                                                   
                                                                                     
     *note assertTrue(x): 52a.                     ‘bool(x) is True’
                                                   
                                                                                     
     *note assertFalse(x): 52b.                    ‘bool(x) is False’
                                                   
                                                                                     
     *note assertIs(a, b): 1386.                   ‘a is b’                          3.1
                                                                                     
                                                                                     
     *note assertIsNot(a, b): 1387.                ‘a is not b’                      3.1
                                                                                     
                                                                                     
     *note assertIsNone(x): 12d1.                  ‘x is None’                       3.1
                                                                                     
                                                                                     
     *note assertIsNotNone(x): 12d2.               ‘x is not None’                   3.1
                                                                                     
                                                                                     
     *note assertIn(a, b): 138f.                   ‘a in b’                          3.1
                                                                                     
                                                                                     
     *note assertNotIn(a, b): 1390.                ‘a not in b’                      3.1
                                                                                     
                                                                                     
     *note assertIsInstance(a, b): 1388.           ‘isinstance(a, b)’                3.2
                                                                                     
                                                                                     
     *note assertNotIsInstance(a, b): 1389.        ‘not isinstance(a, b)’            3.2
                                                                                     

     All the assert methods accept a 'msg' argument that, if specified,
     is used as the error message on failure (see also *note
     longMessage: 1380.).  Note that the 'msg' keyword argument can be
     passed to *note assertRaises(): 530, *note assertRaisesRegex():
     532, *note assertWarns(): 11a8, *note assertWarnsRegex(): 11a9.
     only when they are used as a context manager.

      -- Method: assertEqual (first, second, msg=None)

          Test that 'first' and 'second' are equal.  If the values do
          not compare equal, the test will fail.

          In addition, if 'first' and 'second' are the exact same type
          and one of list, tuple, dict, set, frozenset or str or any
          type that a subclass registers with *note
          addTypeEqualityFunc(): 1393. the type-specific equality
          function will be called in order to generate a more useful
          default error message (see also the *note list of
          type-specific methods: 42c6.).

          Changed in version 3.1: Added the automatic calling of
          type-specific equality function.

          Changed in version 3.2: *note assertMultiLineEqual(): 138e.
          added as the default type equality function for comparing
          strings.

      -- Method: assertNotEqual (first, second, msg=None)

          Test that 'first' and 'second' are not equal.  If the values
          do compare equal, the test will fail.

      -- Method: assertTrue (expr, msg=None)
      -- Method: assertFalse (expr, msg=None)

          Test that 'expr' is true (or false).

          Note that this is equivalent to ‘bool(expr) is True’ and not
          to ‘expr is True’ (use ‘assertIs(expr, True)’ for the latter).
          This method should also be avoided when more specific methods
          are available (e.g.  ‘assertEqual(a, b)’ instead of
          ‘assertTrue(a == b)’), because they provide a better error
          message in case of failure.

      -- Method: assertIs (first, second, msg=None)
      -- Method: assertIsNot (first, second, msg=None)

          Test that 'first' and 'second' are (or are not) the same
          object.

          Added in version 3.1.

      -- Method: assertIsNone (expr, msg=None)
      -- Method: assertIsNotNone (expr, msg=None)

          Test that 'expr' is (or is not) ‘None’.

          Added in version 3.1.

      -- Method: assertIn (member, container, msg=None)
      -- Method: assertNotIn (member, container, msg=None)

          Test that 'member' is (or is not) in 'container'.

          Added in version 3.1.

      -- Method: assertIsInstance (obj, cls, msg=None)
      -- Method: assertNotIsInstance (obj, cls, msg=None)

          Test that 'obj' is (or is not) an instance of 'cls' (which can
          be a class or a tuple of classes, as supported by *note
          isinstance(): 445.).  To check for the exact type, use *note
          assertIs(type(obj), cls): 1386.

          Added in version 3.2.

     It is also possible to check the production of exceptions,
     warnings, and log messages using the following methods:

     Method                                                        Checks that                                New in
                                                                                                              
     --------------------------------------------------------------------------------------------------------------------------
                                                                                                              
     *note assertRaises(exc, fun, *args, **kwds): 530.             ‘fun(*args, **kwds)’ raises 'exc'
                                                                   
                                                                                                              
     *note assertRaisesRegex(exc, r, fun, *args, **kwds): 532.     ‘fun(*args, **kwds)’ raises 'exc' and      3.1
                                                                   the message matches regex 'r'              
                                                                   
                                                                                                              
     *note assertWarns(warn, fun, *args, **kwds): 11a8.            ‘fun(*args, **kwds)’ raises 'warn'         3.2
                                                                                                              
                                                                                                              
     *note assertWarnsRegex(warn, r, fun, *args, **kwds): 11a9.    ‘fun(*args, **kwds)’ raises 'warn' and     3.2
                                                                   the message matches regex 'r'              
                                                                   
                                                                                                              
     *note assertLogs(logger, level): 85f.                         The ‘with’ block logs on 'logger' with     3.4
                                                                   minimum 'level'                            
                                                                   
                                                                                                              
     *note assertNoLogs(logger, level): 85e.                       The ‘with’ block does not log on           3.10
                                                                                                              
                                                                        'logger' with minimum 'level'
                                                                   

      -- Method: assertRaises (exception, callable, *args, **kwds)

      -- Method: assertRaises (exception, *, msg=None)

          Test that an exception is raised when 'callable' is called
          with any positional or keyword arguments that are also passed
          to ‘assertRaises()’.  The test passes if 'exception' is
          raised, is an error if another exception is raised, or fails
          if no exception is raised.  To catch any of a group of
          exceptions, a tuple containing the exception classes may be
          passed as 'exception'.

          If only the 'exception' and possibly the 'msg' arguments are
          given, return a context manager so that the code under test
          can be written inline rather than as a function:

               with self.assertRaises(SomeException):
                   do_something()

          When used as a context manager, ‘assertRaises()’ accepts the
          additional keyword argument 'msg'.

          The context manager will store the caught exception object in
          its ‘exception’ attribute.  This can be useful if the
          intention is to perform additional checks on the exception
          raised:

               with self.assertRaises(SomeException) as cm:
                   do_something()

               the_exception = cm.exception
               self.assertEqual(the_exception.error_code, 3)

          Changed in version 3.1: Added the ability to use
          ‘assertRaises()’ as a context manager.

          Changed in version 3.2: Added the ‘exception’ attribute.

          Changed in version 3.3: Added the 'msg' keyword argument when
          used as a context manager.

      -- Method: assertRaisesRegex (exception, regex, callable, *args,
               **kwds)

      -- Method: assertRaisesRegex (exception, regex, *, msg=None)

          Like *note assertRaises(): 530. but also tests that 'regex'
          matches on the string representation of the raised exception.
          'regex' may be a regular expression object or a string
          containing a regular expression suitable for use by *note
          re.search(): 1272.  Examples:

               self.assertRaisesRegex(ValueError, "invalid literal for.*XYZ'$",
                                      int, 'XYZ')

          or:

               with self.assertRaisesRegex(ValueError, 'literal'):
                  int('XYZ')

          Added in version 3.1: Added under the name
          ‘assertRaisesRegexp’.

          Changed in version 3.2: Renamed to ‘assertRaisesRegex()’.

          Changed in version 3.3: Added the 'msg' keyword argument when
          used as a context manager.

      -- Method: assertWarns (warning, callable, *args, **kwds)

      -- Method: assertWarns (warning, *, msg=None)

          Test that a warning is triggered when 'callable' is called
          with any positional or keyword arguments that are also passed
          to ‘assertWarns()’.  The test passes if 'warning' is triggered
          and fails if it isn’t.  Any exception is an error.  To catch
          any of a group of warnings, a tuple containing the warning
          classes may be passed as 'warnings'.

          If only the 'warning' and possibly the 'msg' arguments are
          given, return a context manager so that the code under test
          can be written inline rather than as a function:

               with self.assertWarns(SomeWarning):
                   do_something()

          When used as a context manager, ‘assertWarns()’ accepts the
          additional keyword argument 'msg'.

          The context manager will store the caught warning object in
          its ‘warning’ attribute, and the source line which triggered
          the warnings in the ‘filename’ and ‘lineno’ attributes.  This
          can be useful if the intention is to perform additional checks
          on the warning caught:

               with self.assertWarns(SomeWarning) as cm:
                   do_something()

               self.assertIn('myfile.py', cm.filename)
               self.assertEqual(320, cm.lineno)

          This method works regardless of the warning filters in place
          when it is called.

          Added in version 3.2.

          Changed in version 3.3: Added the 'msg' keyword argument when
          used as a context manager.

      -- Method: assertWarnsRegex (warning, regex, callable, *args,
               **kwds)

      -- Method: assertWarnsRegex (warning, regex, *, msg=None)

          Like *note assertWarns(): 11a8. but also tests that 'regex'
          matches on the message of the triggered warning.  'regex' may
          be a regular expression object or a string containing a
          regular expression suitable for use by *note re.search():
          1272.  Example:

               self.assertWarnsRegex(DeprecationWarning,
                                     r'legacy_function\(\) is deprecated',
                                     legacy_function, 'XYZ')

          or:

               with self.assertWarnsRegex(RuntimeWarning, 'unsafe frobnicating'):
                   frobnicate('/etc/passwd')

          Added in version 3.2.

          Changed in version 3.3: Added the 'msg' keyword argument when
          used as a context manager.

      -- Method: assertLogs (logger=None, level=None)

          A context manager to test that at least one message is logged
          on the 'logger' or one of its children, with at least the
          given 'level'.

          If given, 'logger' should be a *note logging.Logger: b6a.
          object or a *note str: 44f. giving the name of a logger.  The
          default is the root logger, which will catch all messages that
          were not blocked by a non-propagating descendent logger.

          If given, 'level' should be either a numeric logging level or
          its string equivalent (for example either ‘"ERROR"’ or *note
          logging.ERROR: 1e98.).  The default is *note logging.INFO:
          1e96.

          The test passes if at least one message emitted inside the
          ‘with’ block matches the 'logger' and 'level' conditions,
          otherwise it fails.

          The object returned by the context manager is a recording
          helper which keeps tracks of the matching log messages.  It
          has two attributes:

           -- Attribute: records

               A list of *note logging.LogRecord: 1021. objects of the
               matching log messages.

           -- Attribute: output

               A list of *note str: 44f. objects with the formatted
               output of matching messages.

          Example:

               with self.assertLogs('foo', level='INFO') as cm:
                   logging.getLogger('foo').info('first message')
                   logging.getLogger('foo.bar').error('second message')
               self.assertEqual(cm.output, ['INFO:foo:first message',
                                            'ERROR:foo.bar:second message'])

          Added in version 3.4.

      -- Method: assertNoLogs (logger=None, level=None)

          A context manager to test that no messages are logged on the
          'logger' or one of its children, with at least the given
          'level'.

          If given, 'logger' should be a *note logging.Logger: b6a.
          object or a *note str: 44f. giving the name of a logger.  The
          default is the root logger, which will catch all messages.

          If given, 'level' should be either a numeric logging level or
          its string equivalent (for example either ‘"ERROR"’ or *note
          logging.ERROR: 1e98.).  The default is *note logging.INFO:
          1e96.

          Unlike *note assertLogs(): 85f, nothing will be returned by
          the context manager.

          Added in version 3.10.

     There are also other methods used to perform more specific checks,
     such as:

     Method                                      Checks that                          New in
                                                                                      
     ----------------------------------------------------------------------------------------------------
                                                                                      
     *note assertAlmostEqual(a, b): 52e.         ‘round(a-b, 7) == 0’
                                                 
                                                                                      
     *note assertNotAlmostEqual(a, b): 52f.      ‘round(a-b, 7) != 0’
                                                 
                                                                                      
     *note assertGreater(a, b): 138a.            ‘a > b’                              3.1
                                                                                      
                                                                                      
     *note assertGreaterEqual(a, b): 138b.       ‘a >= b’                             3.1
                                                                                      
                                                                                      
     *note assertLess(a, b): 138c.               ‘a < b’                              3.1
                                                                                      
                                                                                      
     *note assertLessEqual(a, b): 138d.          ‘a <= b’                             3.1
                                                                                      
                                                                                      
     *note assertRegex(s, r): 531.               ‘r.search(s)’                        3.1
                                                                                      
                                                                                      
     *note assertNotRegex(s, r): 533.            ‘not r.search(s)’                    3.2
                                                                                      
                                                                                      
     *note assertCountEqual(a, b): 1270.         'a' and 'b' have the same elements   3.2
                                                 in the same number, regardless of    
                                                 their order.
                                                 

      -- Method: assertAlmostEqual (first, second, places=7, msg=None,
               delta=None)
      -- Method: assertNotAlmostEqual (first, second, places=7,
               msg=None, delta=None)

          Test that 'first' and 'second' are approximately (or not
          approximately) equal by computing the difference, rounding to
          the given number of decimal 'places' (default 7), and
          comparing to zero.  Note that these methods round the values
          to the given number of 'decimal places' (i.e.  like the *note
          round(): 1322. function) and not 'significant digits'.

          If 'delta' is supplied instead of 'places' then the difference
          between 'first' and 'second' must be less or equal to (or
          greater than) 'delta'.

          Supplying both 'delta' and 'places' raises a *note TypeError:
          2c3.

          Changed in version 3.2: ‘assertAlmostEqual()’ automatically
          considers almost equal objects that compare equal.
          ‘assertNotAlmostEqual()’ automatically fails if the objects
          compare equal.  Added the 'delta' keyword argument.

      -- Method: assertGreater (first, second, msg=None)
      -- Method: assertGreaterEqual (first, second, msg=None)
      -- Method: assertLess (first, second, msg=None)
      -- Method: assertLessEqual (first, second, msg=None)

          Test that 'first' is respectively >, >=, < or <= than 'second'
          depending on the method name.  If not, the test will fail:

               >>> self.assertGreaterEqual(3, 4)
               AssertionError: "3" unexpectedly not greater than or equal to "4"

          Added in version 3.1.

      -- Method: assertRegex (text, regex, msg=None)
      -- Method: assertNotRegex (text, regex, msg=None)

          Test that a 'regex' search matches (or does not match) 'text'.
          In case of failure, the error message will include the pattern
          and the 'text' (or the pattern and the part of 'text' that
          unexpectedly matched).  'regex' may be a regular expression
          object or a string containing a regular expression suitable
          for use by *note re.search(): 1272.

          Added in version 3.1: Added under the name
          ‘assertRegexpMatches’.

          Changed in version 3.2: The method ‘assertRegexpMatches()’ has
          been renamed to ‘assertRegex()’.

          Added in version 3.2: ‘assertNotRegex()’.

      -- Method: assertCountEqual (first, second, msg=None)

          Test that sequence 'first' contains the same elements as
          'second', regardless of their order.  When they don’t, an
          error message listing the differences between the sequences
          will be generated.

          Duplicate elements are 'not' ignored when comparing 'first'
          and 'second'.  It verifies whether each element has the same
          count in both sequences.  Equivalent to:
          ‘assertEqual(Counter(list(first)), Counter(list(second)))’ but
          works with sequences of unhashable objects as well.

          Added in version 3.2.

     The *note assertEqual(): 52c. method dispatches the equality check
     for objects of the same type to different type-specific methods.
     These methods are already implemented for most of the built-in
     types, but it’s also possible to register new methods using *note
     addTypeEqualityFunc(): 1393.:

      -- Method: addTypeEqualityFunc (typeobj, function)

          Registers a type-specific method called by *note
          assertEqual(): 52c. to check if two objects of exactly the
          same 'typeobj' (not subclasses) compare equal.  'function'
          must take two positional arguments and a third msg=None
          keyword argument just as ‘assertEqual()’ does.  It must raise
          *note self.failureException(msg): 425d. when inequality
          between the first two parameters is detected – possibly
          providing useful information and explaining the inequalities
          in details in the error message.

          Added in version 3.1.

     The list of type-specific methods automatically used by *note
     assertEqual(): 52c. are summarized in the following table.  Note
     that it’s usually not necessary to invoke these methods directly.

     Method                                        Used to compare                   New in
                                                                                     
     ---------------------------------------------------------------------------------------------------
                                                                                     
     *note assertMultiLineEqual(a, b): 138e.       strings                           3.1
                                                                                     
                                                                                     
     *note assertSequenceEqual(a, b): 12d0.        sequences                         3.1
                                                                                     
                                                                                     
     *note assertListEqual(a, b): 12ce.            lists                             3.1
                                                                                     
                                                                                     
     *note assertTupleEqual(a, b): 12cf.           tuples                            3.1
                                                                                     
                                                                                     
     *note assertSetEqual(a, b): 12cc.             sets or frozensets                3.1
                                                                                     
                                                                                     
     *note assertDictEqual(a, b): 12cd.            dicts                             3.1
                                                                                     

      -- Method: assertMultiLineEqual (first, second, msg=None)

          Test that the multiline string 'first' is equal to the string
          'second'.  When not equal a diff of the two strings
          highlighting the differences will be included in the error
          message.  This method is used by default when comparing
          strings with *note assertEqual(): 52c.

          Added in version 3.1.

      -- Method: assertSequenceEqual (first, second, msg=None,
               seq_type=None)

          Tests that two sequences are equal.  If a 'seq_type' is
          supplied, both 'first' and 'second' must be instances of
          'seq_type' or a failure will be raised.  If the sequences are
          different an error message is constructed that shows the
          difference between the two.

          This method is not called directly by *note assertEqual():
          52c, but it’s used to implement *note assertListEqual(): 12ce.
          and *note assertTupleEqual(): 12cf.

          Added in version 3.1.

      -- Method: assertListEqual (first, second, msg=None)
      -- Method: assertTupleEqual (first, second, msg=None)

          Tests that two lists or tuples are equal.  If not, an error
          message is constructed that shows only the differences between
          the two.  An error is also raised if either of the parameters
          are of the wrong type.  These methods are used by default when
          comparing lists or tuples with *note assertEqual(): 52c.

          Added in version 3.1.

      -- Method: assertSetEqual (first, second, msg=None)

          Tests that two sets are equal.  If not, an error message is
          constructed that lists the differences between the sets.  This
          method is used by default when comparing sets or frozensets
          with *note assertEqual(): 52c.

          Fails if either of 'first' or 'second' does not have a *note
          difference(): 23ef. method.

          Added in version 3.1.

      -- Method: assertDictEqual (first, second, msg=None)

          Test that two dictionaries are equal.  If not, an error
          message is constructed that shows the differences in the
          dictionaries.  This method will be used by default to compare
          dictionaries in calls to *note assertEqual(): 52c.

          Added in version 3.1.

     Finally the ‘TestCase’ provides the following methods and
     attributes:

      -- Method: fail (msg=None)

          Signals a test failure unconditionally, with 'msg' or ‘None’
          for the error message.

      -- Attribute: failureException

          This class attribute gives the exception raised by the test
          method.  If a test framework needs to use a specialized
          exception, possibly to carry additional information, it must
          subclass this exception in order to “play fair” with the
          framework.  The initial value of this attribute is *note
          AssertionError: 6ac.

      -- Attribute: longMessage

          This class attribute determines what happens when a custom
          failure message is passed as the msg argument to an assertXYY
          call that fails.  ‘True’ is the default value.  In this case,
          the custom message is appended to the end of the standard
          failure message.  When set to ‘False’, the custom message
          replaces the standard message.

          The class setting can be overridden in individual test methods
          by assigning an instance attribute, self.longMessage, to
          ‘True’ or ‘False’ before calling the assert methods.

          The class setting gets reset before each test call.

          Added in version 3.1.

      -- Attribute: maxDiff

          This attribute controls the maximum length of diffs output by
          assert methods that report diffs on failure.  It defaults to
          80*8 characters.  Assert methods affected by this attribute
          are *note assertSequenceEqual(): 12d0. (including all the
          sequence comparison methods that delegate to it), *note
          assertDictEqual(): 12cd. and *note assertMultiLineEqual():
          138e.

          Setting ‘maxDiff’ to ‘None’ means that there is no maximum
          length of diffs.

          Added in version 3.2.

     Testing frameworks can use the following methods to collect
     information on the test:

      -- Method: countTestCases ()

          Return the number of tests represented by this test object.
          For ‘TestCase’ instances, this will always be ‘1’.

      -- Method: defaultTestResult ()

          Return an instance of the test result class that should be
          used for this test case class (if no other result instance is
          provided to the *note run(): 11aa. method).

          For ‘TestCase’ instances, this will always be an instance of
          *note TestResult: 11ab.; subclasses of ‘TestCase’ should
          override this as necessary.

      -- Method: id ()

          Return a string identifying the specific test case.  This is
          usually the full name of the test method, including the module
          and class name.

      -- Method: shortDescription ()

          Returns a description of the test, or ‘None’ if no description
          has been provided.  The default implementation of this method
          returns the first line of the test method’s docstring, if
          available, or ‘None’.

          Changed in version 3.1: In 3.1 this was changed to add the
          test name to the short description even in the presence of a
          docstring.  This caused compatibility issues with unittest
          extensions and adding the test name was moved to the *note
          TextTestResult: 534. in Python 3.2.

      -- Method: addCleanup (function, /, *args, **kwargs)

          Add a function to be called after *note tearDown(): 1385. to
          cleanup resources used during the test.  Functions will be
          called in reverse order to the order they are added (LIFO).
          They are called with any arguments and keyword arguments
          passed into ‘addCleanup()’ when they are added.

          If *note setUp(): 1384. fails, meaning that *note tearDown():
          1385. is not called, then any cleanup functions added will
          still be called.

          Added in version 3.1.

      -- Method: enterContext (cm)

          Enter the supplied *note context manager: 5d7.  If successful,
          also add its *note __exit__(): 1349. method as a cleanup
          function by *note addCleanup(): a90. and return the result of
          the *note __enter__(): 5cb. method.

          Added in version 3.11.

      -- Method: doCleanups ()

          This method is called unconditionally after *note tearDown():
          1385, or after *note setUp(): 1384. if ‘setUp()’ raises an
          exception.

          It is responsible for calling all the cleanup functions added
          by *note addCleanup(): a90.  If you need cleanup functions to
          be called 'prior' to *note tearDown(): 1385. then you can call
          ‘doCleanups()’ yourself.

          ‘doCleanups()’ pops methods off the stack of cleanup functions
          one at a time, so it can be called at any time.

          Added in version 3.1.

      -- Method: classmethod addClassCleanup (function, /, *args,
               **kwargs)

          Add a function to be called after *note tearDownClass(): 1382.
          to cleanup resources used during the test class.  Functions
          will be called in reverse order to the order they are added
          (LIFO).  They are called with any arguments and keyword
          arguments passed into ‘addClassCleanup()’ when they are added.

          If *note setUpClass(): a5c. fails, meaning that *note
          tearDownClass(): 1382. is not called, then any cleanup
          functions added will still be called.

          Added in version 3.8.

      -- Method: classmethod enterClassContext (cm)

          Enter the supplied *note context manager: 5d7.  If successful,
          also add its *note __exit__(): 1349. method as a cleanup
          function by *note addClassCleanup(): a5a. and return the
          result of the *note __enter__(): 5cb. method.

          Added in version 3.11.

      -- Method: classmethod doClassCleanups ()

          This method is called unconditionally after *note
          tearDownClass(): 1382, or after *note setUpClass(): a5c. if
          ‘setUpClass()’ raises an exception.

          It is responsible for calling all the cleanup functions added
          by *note addClassCleanup(): a5a.  If you need cleanup
          functions to be called 'prior' to *note tearDownClass(): 1382.
          then you can call ‘doClassCleanups()’ yourself.

          ‘doClassCleanups()’ pops methods off the stack of cleanup
          functions one at a time, so it can be called at any time.

          Added in version 3.8.

 -- Class: unittest.IsolatedAsyncioTestCase (methodName='runTest')

     This class provides an API similar to *note TestCase: 451. and also
     accepts coroutines as test functions.

     Added in version 3.8.

      -- Attribute: loop_factory

          The 'loop_factory' passed to *note asyncio.Runner: 603.
          Override in subclasses with *note asyncio.EventLoop: 1806. to
          avoid using the asyncio policy system.

          Added in version 3.13.

      -- Method: async asyncSetUp ()

          Method called to prepare the test fixture.  This is called
          after *note TestCase.setUp(): 1384.  This is called
          immediately before calling the test method; other than *note
          AssertionError: 6ac. or *note SkipTest: 101f, any exception
          raised by this method will be considered an error rather than
          a test failure.  The default implementation does nothing.

      -- Method: async asyncTearDown ()

          Method called immediately after the test method has been
          called and the result recorded.  This is called before *note
          tearDown(): 1385.  This is called even if the test method
          raised an exception, so the implementation in subclasses may
          need to be particularly careful about checking internal state.
          Any exception, other than *note AssertionError: 6ac. or *note
          SkipTest: 101f, raised by this method will be considered an
          additional error rather than a test failure (thus increasing
          the total number of reported errors).  This method will only
          be called if the *note asyncSetUp(): 42d0. succeeds,
          regardless of the outcome of the test method.  The default
          implementation does nothing.

      -- Method: addAsyncCleanup (function, /, *args, **kwargs)

          This method accepts a coroutine that can be used as a cleanup
          function.

      -- Method: async enterAsyncContext (cm)

          Enter the supplied *note asynchronous context manager: 5da.
          If successful, also add its *note __aexit__(): 1734. method as
          a cleanup function by *note addAsyncCleanup(): 42d2. and
          return the result of the *note __aenter__(): 2181. method.

          Added in version 3.11.

      -- Method: run (result=None)

          Sets up a new event loop to run the test, collecting the
          result into the *note TestResult: 11ab. object passed as
          'result'.  If 'result' is omitted or ‘None’, a temporary
          result object is created (by calling the *note
          defaultTestResult(): 42c5. method) and used.  The result
          object is returned to ‘run()’’s caller.  At the end of the
          test all the tasks in the event loop are cancelled.

     An example illustrating the order:

          from unittest import IsolatedAsyncioTestCase

          events = []


          class Test(IsolatedAsyncioTestCase):


              def setUp(self):
                  events.append("setUp")

              async def asyncSetUp(self):
                  self._async_connection = await AsyncConnection()
                  events.append("asyncSetUp")

              async def test_response(self):
                  events.append("test_response")
                  response = await self._async_connection.get("https://example.com")
                  self.assertEqual(response.status_code, 200)
                  self.addAsyncCleanup(self.on_cleanup)

              def tearDown(self):
                  events.append("tearDown")

              async def asyncTearDown(self):
                  await self._async_connection.close()
                  events.append("asyncTearDown")

              async def on_cleanup(self):
                  events.append("cleanup")

          if __name__ == "__main__":
              unittest.main()

     After running the test, ‘events’ would contain ‘["setUp",
     "asyncSetUp", "test_response", "asyncTearDown", "tearDown",
     "cleanup"]’.

 -- Class: unittest.FunctionTestCase (testFunc, setUp=None,
          tearDown=None, description=None)

     This class implements the portion of the *note TestCase: 451.
     interface which allows the test runner to drive the test, but does
     not provide the methods which test code can use to check and report
     errors.  This is used to create test cases using legacy test code,
     allowing it to be integrated into a ‘unittest’-based test
     framework.


File: python.info,  Node: Grouping tests,  Next: Loading and running tests,  Prev: Test cases,  Up: Classes and functions

5.26.5.11 Grouping tests
........................

 -- Class: unittest.TestSuite (tests=())

     This class represents an aggregation of individual test cases and
     test suites.  The class presents the interface needed by the test
     runner to allow it to be run as any other test case.  Running a
     ‘TestSuite’ instance is the same as iterating over the suite,
     running each test individually.

     If 'tests' is given, it must be an iterable of individual test
     cases or other test suites that will be used to build the suite
     initially.  Additional methods are provided to add test cases and
     suites to the collection later on.

     ‘TestSuite’ objects behave much like *note TestCase: 451. objects,
     except they do not actually implement a test.  Instead, they are
     used to aggregate tests into groups of tests that should be run
     together.  Some additional methods are available to add tests to
     ‘TestSuite’ instances:

      -- Method: addTest (test)

          Add a *note TestCase: 451. or ‘TestSuite’ to the suite.

      -- Method: addTests (tests)

          Add all the tests from an iterable of *note TestCase: 451. and
          ‘TestSuite’ instances to this test suite.

          This is equivalent to iterating over 'tests', calling *note
          addTest(): 42d6. for each element.

     ‘TestSuite’ shares the following methods with *note TestCase: 451.:

      -- Method: run (result)

          Run the tests associated with this suite, collecting the
          result into the test result object passed as 'result'.  Note
          that unlike *note TestCase.run(): 11aa, ‘TestSuite.run()’
          requires the result object to be passed in.

      -- Method: debug ()

          Run the tests associated with this suite without collecting
          the result.  This allows exceptions raised by the test to be
          propagated to the caller and can be used to support running
          tests under a debugger.

      -- Method: countTestCases ()

          Return the number of tests represented by this test object,
          including all individual tests and sub-suites.

      -- Method: __iter__ ()

          Tests grouped by a ‘TestSuite’ are always accessed by
          iteration.  Subclasses can lazily provide tests by overriding
          ‘__iter__()’.  Note that this method may be called several
          times on a single suite (for example when counting tests or
          comparing for equality) so the tests returned by repeated
          iterations before *note TestSuite.run(): 42d8. must be the
          same for each call iteration.  After ‘TestSuite.run()’,
          callers should not rely on the tests returned by this method
          unless the caller uses a subclass that overrides
          ‘TestSuite._removeTestAtIndex()’ to preserve test references.

          Changed in version 3.2: In earlier versions the ‘TestSuite’
          accessed tests directly rather than through iteration, so
          overriding ‘__iter__()’ wasn’t sufficient for providing tests.

          Changed in version 3.4: In earlier versions the ‘TestSuite’
          held references to each *note TestCase: 451. after *note
          TestSuite.run(): 42d8.  Subclasses can restore that behavior
          by overriding ‘TestSuite._removeTestAtIndex()’.

     In the typical usage of a ‘TestSuite’ object, the *note run():
     42d8. method is invoked by a ‘TestRunner’ rather than by the
     end-user test harness.


File: python.info,  Node: Loading and running tests,  Prev: Grouping tests,  Up: Classes and functions

5.26.5.12 Loading and running tests
...................................

 -- Class: unittest.TestLoader

     The ‘TestLoader’ class is used to create test suites from classes
     and modules.  Normally, there is no need to create an instance of
     this class; the ‘unittest’ module provides an instance that can be
     shared as *note unittest.defaultTestLoader: 42dc.  Using a subclass
     or instance, however, allows customization of some configurable
     properties.

     ‘TestLoader’ objects have the following attributes:

      -- Attribute: errors

          A list of the non-fatal errors encountered while loading
          tests.  Not reset by the loader at any point.  Fatal errors
          are signalled by the relevant method raising an exception to
          the caller.  Non-fatal errors are also indicated by a
          synthetic test that will raise the original error when run.

          Added in version 3.5.

     ‘TestLoader’ objects have the following methods:

      -- Method: loadTestsFromTestCase (testCaseClass)

          Return a suite of all test cases contained in the *note
          TestCase: 451.-derived ‘testCaseClass’.

          A test case instance is created for each method named by *note
          getTestCaseNames(): 291.  By default these are the method
          names beginning with ‘test’.  If ‘getTestCaseNames()’ returns
          no methods, but the ‘runTest()’ method is implemented, a
          single test case is created for that method instead.

      -- Method: loadTestsFromModule (module, *, pattern=None)

          Return a suite of all test cases contained in the given
          module.  This method searches 'module' for classes derived
          from *note TestCase: 451. and creates an instance of the class
          for each test method defined for the class.

               Note: While using a hierarchy of *note TestCase:
               451.-derived classes can be convenient in sharing
               fixtures and helper functions, defining test methods on
               base classes that are not intended to be instantiated
               directly does not play well with this method.  Doing so,
               however, can be useful when the fixtures are different
               and defined in subclasses.

          If a module provides a ‘load_tests’ function it will be called
          to load the tests.  This allows modules to customize test
          loading.  This is the *note load_tests protocol: 42b5.  The
          'pattern' argument is passed as the third argument to
          ‘load_tests’.

          Changed in version 3.2: Support for ‘load_tests’ added.

          Changed in version 3.5: Support for a keyword-only argument
          'pattern' has been added.

          Changed in version 3.12: The undocumented and unofficial
          'use_load_tests' parameter has been removed.

      -- Method: loadTestsFromName (name, module=None)

          Return a suite of all test cases given a string specifier.

          The specifier 'name' is a “dotted name” that may resolve
          either to a module, a test case class, a test method within a
          test case class, a *note TestSuite: e26. instance, or a
          callable object which returns a *note TestCase: 451. or
          ‘TestSuite’ instance.  These checks are applied in the order
          listed here; that is, a method on a possible test case class
          will be picked up as “a test method within a test case class”,
          rather than “a callable object”.

          For example, if you have a module ‘SampleTests’ containing a
          *note TestCase: 451.-derived class ‘SampleTestCase’ with three
          test methods (‘test_one()’, ‘test_two()’, and ‘test_three()’),
          the specifier ‘'SampleTests.SampleTestCase'’ would cause this
          method to return a suite which will run all three test
          methods.  Using the specifier
          ‘'SampleTests.SampleTestCase.test_two'’ would cause it to
          return a test suite which will run only the ‘test_two()’ test
          method.  The specifier can refer to modules and packages which
          have not been imported; they will be imported as a
          side-effect.

          The method optionally resolves 'name' relative to the given
          'module'.

          Changed in version 3.5: If an *note ImportError: 41c. or *note
          AttributeError: 34e. occurs while traversing 'name' then a
          synthetic test that raises that error when run will be
          returned.  These errors are included in the errors accumulated
          by self.errors.

      -- Method: loadTestsFromNames (names, module=None)

          Similar to *note loadTestsFromName(): 1391, but takes a
          sequence of names rather than a single name.  The return value
          is a test suite which supports all the tests defined for each
          name.

      -- Method: getTestCaseNames (testCaseClass)

          Return a sorted sequence of method names found within
          'testCaseClass'; this should be a subclass of *note TestCase:
          451.

      -- Method: discover (start_dir, pattern='test*.py',
               top_level_dir=None)

          Find all the test modules by recursing into subdirectories
          from the specified start directory, and return a TestSuite
          object containing them.  Only test files that match 'pattern'
          will be loaded.  (Using shell style pattern matching.)  Only
          module names that are importable (i.e.  are valid Python
          identifiers) will be loaded.

          All test modules must be importable from the top level of the
          project.  If the start directory is not the top level
          directory then 'top_level_dir' must be specified separately.

          If importing a module fails, for example due to a syntax
          error, then this will be recorded as a single error and
          discovery will continue.  If the import failure is due to
          *note SkipTest: 101f. being raised, it will be recorded as a
          skip instead of an error.

          If a package (a directory containing a file named
          ‘__init__.py’) is found, the package will be checked for a
          ‘load_tests’ function.  If this exists then it will be called
          ‘package.load_tests(loader, tests, pattern)’.  Test discovery
          takes care to ensure that a package is only checked for tests
          once during an invocation, even if the load_tests function
          itself calls ‘loader.discover’.

          If ‘load_tests’ exists then discovery does 'not' recurse into
          the package, ‘load_tests’ is responsible for loading all tests
          in the package.

          The pattern is deliberately not stored as a loader attribute
          so that packages can continue discovery themselves.

          'top_level_dir' is stored internally, and used as a default to
          any nested calls to ‘discover()’.  That is, if a package’s
          ‘load_tests’ calls ‘loader.discover()’, it does not need to
          pass this argument.

          'start_dir' can be a dotted module name as well as a
          directory.

          Added in version 3.2.

          Changed in version 3.4: Modules that raise *note SkipTest:
          101f. on import are recorded as skips, not errors.

          Changed in version 3.4: 'start_dir' can be a *note namespace
          packages: 1e06.

          Changed in version 3.4: Paths are sorted before being imported
          so that execution order is the same even if the underlying
          file system’s ordering is not dependent on file name.

          Changed in version 3.5: Found packages are now checked for
          ‘load_tests’ regardless of whether their path matches
          'pattern', because it is impossible for a package name to
          match the default pattern.

          Changed in version 3.11: 'start_dir' can not be a *note
          namespace packages: 1e06.  It has been broken since Python 3.7
          and Python 3.11 officially remove it.

          Changed in version 3.13: 'top_level_dir' is only stored for
          the duration of 'discover' call.

     The following attributes of a ‘TestLoader’ can be configured either
     by subclassing or assignment on an instance:

      -- Attribute: testMethodPrefix

          String giving the prefix of method names which will be
          interpreted as test methods.  The default value is ‘'test'’.

          This affects *note getTestCaseNames(): 291. and all the
          ‘loadTestsFrom*’ methods.

      -- Attribute: sortTestMethodsUsing

          Function to be used to compare method names when sorting them
          in *note getTestCaseNames(): 291. and all the ‘loadTestsFrom*’
          methods.

      -- Attribute: suiteClass

          Callable object that constructs a test suite from a list of
          tests.  No methods on the resulting object are needed.  The
          default value is the *note TestSuite: e26. class.

          This affects all the ‘loadTestsFrom*’ methods.

      -- Attribute: testNamePatterns

          List of Unix shell-style wildcard test name patterns that test
          methods have to match to be included in test suites (see ‘-k’
          option).

          If this attribute is not ‘None’ (the default), all test
          methods to be included in test suites must match one of the
          patterns in this list.  Note that matches are always performed
          using *note fnmatch.fnmatchcase(): 19fb, so unlike patterns
          passed to the ‘-k’ option, simple substring patterns will have
          to be converted using ‘*’ wildcards.

          This affects all the ‘loadTestsFrom*’ methods.

          Added in version 3.7.

 -- Class: unittest.TestResult

     This class is used to compile information about which tests have
     succeeded and which have failed.

     A ‘TestResult’ object stores the results of a set of tests.  The
     *note TestCase: 451. and *note TestSuite: e26. classes ensure that
     results are properly recorded; test authors do not need to worry
     about recording the outcome of tests.

     Testing frameworks built on top of ‘unittest’ may want access to
     the ‘TestResult’ object generated by running a set of tests for
     reporting purposes; a ‘TestResult’ instance is returned by the
     ‘TestRunner.run()’ method for this purpose.

     ‘TestResult’ instances have the following attributes that will be
     of interest when inspecting the results of running a set of tests:

      -- Attribute: errors

          A list containing 2-tuples of *note TestCase: 451. instances
          and strings holding formatted tracebacks.  Each tuple
          represents a test which raised an unexpected exception.

      -- Attribute: failures

          A list containing 2-tuples of *note TestCase: 451. instances
          and strings holding formatted tracebacks.  Each tuple
          represents a test where a failure was explicitly signalled
          using the *note assert* methods: 429d.

      -- Attribute: skipped

          A list containing 2-tuples of *note TestCase: 451. instances
          and strings holding the reason for skipping the test.

          Added in version 3.1.

      -- Attribute: expectedFailures

          A list containing 2-tuples of *note TestCase: 451. instances
          and strings holding formatted tracebacks.  Each tuple
          represents an expected failure or error of the test case.

      -- Attribute: unexpectedSuccesses

          A list containing *note TestCase: 451. instances that were
          marked as expected failures, but succeeded.

      -- Attribute: collectedDurations

          A list containing 2-tuples of test case names and floats
          representing the elapsed time of each test which was run.

          Added in version 3.12.

      -- Attribute: shouldStop

          Set to ‘True’ when the execution of tests should stop by *note
          stop(): 42e7.

      -- Attribute: testsRun

          The total number of tests run so far.

      -- Attribute: buffer

          If set to true, ‘sys.stdout’ and ‘sys.stderr’ will be buffered
          in between *note startTest(): 42ea. and *note stopTest():
          42eb. being called.  Collected output will only be echoed onto
          the real ‘sys.stdout’ and ‘sys.stderr’ if the test fails or
          errors.  Any output is also attached to the failure / error
          message.

          Added in version 3.2.

      -- Attribute: failfast

          If set to true *note stop(): 42e7. will be called on the first
          failure or error, halting the test run.

          Added in version 3.2.

      -- Attribute: tb_locals

          If set to true then local variables will be shown in
          tracebacks.

          Added in version 3.5.

      -- Method: wasSuccessful ()

          Return ‘True’ if all tests run so far have passed, otherwise
          returns ‘False’.

          Changed in version 3.4: Returns ‘False’ if there were any
          *note unexpectedSuccesses: 42e5. from tests marked with the
          *note expectedFailure(): 42bc. decorator.

      -- Method: stop ()

          This method can be called to signal that the set of tests
          being run should be aborted by setting the *note shouldStop:
          42e6. attribute to ‘True’.  ‘TestRunner’ objects should
          respect this flag and return without running any additional
          tests.

          For example, this feature is used by the *note TextTestRunner:
          185a. class to stop the test framework when the user signals
          an interrupt from the keyboard.  Interactive tools which
          provide ‘TestRunner’ implementations can use this in a similar
          manner.

     The following methods of the ‘TestResult’ class are used to
     maintain the internal data structures, and may be extended in
     subclasses to support additional reporting requirements.  This is
     particularly useful in building tools which support interactive
     reporting while tests are being run.

      -- Method: startTest (test)

          Called when the test case 'test' is about to be run.

      -- Method: stopTest (test)

          Called after the test case 'test' has been executed,
          regardless of the outcome.

      -- Method: startTestRun ()

          Called once before any tests are executed.

          Added in version 3.1.

      -- Method: stopTestRun ()

          Called once after all tests are executed.

          Added in version 3.1.

      -- Method: addError (test, err)

          Called when the test case 'test' raises an unexpected
          exception.  'err' is a tuple of the form returned by *note
          sys.exc_info(): 68d.: ‘(type, value, traceback)’.

          The default implementation appends a tuple ‘(test,
          formatted_err)’ to the instance’s *note errors: 42e1.
          attribute, where 'formatted_err' is a formatted traceback
          derived from 'err'.

      -- Method: addFailure (test, err)

          Called when the test case 'test' signals a failure.  'err' is
          a tuple of the form returned by *note sys.exc_info(): 68d.:
          ‘(type, value, traceback)’.

          The default implementation appends a tuple ‘(test,
          formatted_err)’ to the instance’s *note failures: 42e2.
          attribute, where 'formatted_err' is a formatted traceback
          derived from 'err'.

      -- Method: addSuccess (test)

          Called when the test case 'test' succeeds.

          The default implementation does nothing.

      -- Method: addSkip (test, reason)

          Called when the test case 'test' is skipped.  'reason' is the
          reason the test gave for skipping.

          The default implementation appends a tuple ‘(test, reason)’ to
          the instance’s *note skipped: 42e3. attribute.

      -- Method: addExpectedFailure (test, err)

          Called when the test case 'test' fails or errors, but was
          marked with the *note expectedFailure(): 42bc. decorator.

          The default implementation appends a tuple ‘(test,
          formatted_err)’ to the instance’s *note expectedFailures:
          42e4. attribute, where 'formatted_err' is a formatted
          traceback derived from 'err'.

      -- Method: addUnexpectedSuccess (test)

          Called when the test case 'test' was marked with the *note
          expectedFailure(): 42bc. decorator, but succeeded.

          The default implementation appends the test to the instance’s
          *note unexpectedSuccesses: 42e5. attribute.

      -- Method: addSubTest (test, subtest, outcome)

          Called when a subtest finishes.  'test' is the test case
          corresponding to the test method.  'subtest' is a custom *note
          TestCase: 451. instance describing the subtest.

          If 'outcome' is *note None: 678, the subtest succeeded.
          Otherwise, it failed with an exception where 'outcome' is a
          tuple of the form returned by *note sys.exc_info(): 68d.:
          ‘(type, value, traceback)’.

          The default implementation does nothing when the outcome is a
          success, and records subtest failures as normal failures.

          Added in version 3.4.

      -- Method: addDuration (test, elapsed)

          Called when the test case finishes.  'elapsed' is the time
          represented in seconds, and it includes the execution of
          cleanup functions.

          Added in version 3.12.

 -- Class: unittest.TextTestResult (stream, descriptions, verbosity, *,
          durations=None)

     A concrete implementation of *note TestResult: 11ab. used by the
     *note TextTestRunner: 185a.  Subclasses should accept ‘**kwargs’ to
     ensure compatibility as the interface changes.

     Added in version 3.2.

     Changed in version 3.12: Added the 'durations' keyword parameter.

 -- Data: unittest.defaultTestLoader

     Instance of the *note TestLoader: 28e. class intended to be shared.
     If no customization of the ‘TestLoader’ is needed, this instance
     can be used instead of repeatedly creating new instances.

 -- Class: unittest.TextTestRunner (stream=None, descriptions=True,
          verbosity=1, failfast=False, buffer=False, resultclass=None,
          warnings=None, *, tb_locals=False, durations=None)

     A basic test runner implementation that outputs results to a
     stream.  If 'stream' is ‘None’, the default, *note sys.stderr: 943.
     is used as the output stream.  This class has a few configurable
     parameters, but is essentially very simple.  Graphical applications
     which run test suites should provide alternate implementations.
     Such implementations should accept ‘**kwargs’ as the interface to
     construct runners changes when features are added to unittest.

     By default this runner shows *note DeprecationWarning: 1a5, *note
     PendingDeprecationWarning: 8d1, *note ResourceWarning: 244. and
     *note ImportWarning: 4fd. even if they are *note ignored by
     default: 42f2.  This behavior can be overridden using Python’s
     ‘-Wd’ or ‘-Wa’ options (see *note Warning control: 1ee0.) and
     leaving 'warnings' to ‘None’.

     Changed in version 3.2: Added the 'warnings' parameter.

     Changed in version 3.2: The default stream is set to *note
     sys.stderr: 943. at instantiation time rather than import time.

     Changed in version 3.5: Added the 'tb_locals' parameter.

     Changed in version 3.12: Added the 'durations' parameter.

      -- Method: _makeResult ()

          This method returns the instance of ‘TestResult’ used by *note
          run(): 42f4.  It is not intended to be called directly, but
          can be overridden in subclasses to provide a custom
          ‘TestResult’.

          ‘_makeResult()’ instantiates the class or callable passed in
          the ‘TextTestRunner’ constructor as the ‘resultclass’
          argument.  It defaults to *note TextTestResult: 534. if no
          ‘resultclass’ is provided.  The result class is instantiated
          with the following arguments:

               stream, descriptions, verbosity

      -- Method: run (test)

          This method is the main public interface to the
          ‘TextTestRunner’.  This method takes a *note TestSuite: e26.
          or *note TestCase: 451. instance.  A *note TestResult: 11ab.
          is created by calling *note _makeResult(): 42f3. and the
          test(s) are run and the results printed to stdout.

 -- Function: unittest.main (module='__main__', defaultTest=None,
          argv=None, testRunner=None,
          testLoader=unittest.defaultTestLoader, exit=True, verbosity=1,
          failfast=None, catchbreak=None, buffer=None, warnings=None)

     A command-line program that loads a set of tests from 'module' and
     runs them; this is primarily for making test modules conveniently
     executable.  The simplest use for this function is to include the
     following line at the end of a test script:

          if __name__ == '__main__':
              unittest.main()

     You can run tests with more detailed information by passing in the
     verbosity argument:

          if __name__ == '__main__':
              unittest.main(verbosity=2)

     The 'defaultTest' argument is either the name of a single test or
     an iterable of test names to run if no test names are specified via
     'argv'.  If not specified or ‘None’ and no test names are provided
     via 'argv', all tests found in 'module' are run.

     The 'argv' argument can be a list of options passed to the program,
     with the first element being the program name.  If not specified or
     ‘None’, the values of *note sys.argv: 12ab. are used.

     The 'testRunner' argument can either be a test runner class or an
     already created instance of it.  By default ‘main’ calls *note
     sys.exit(): 1394. with an exit code indicating success (0) or
     failure (1) of the tests run.  An exit code of 5 indicates that no
     tests were run or skipped.

     The 'testLoader' argument has to be a *note TestLoader: 28e.
     instance, and defaults to *note defaultTestLoader: 42dc.

     ‘main’ supports being used from the interactive interpreter by
     passing in the argument ‘exit=False’.  This displays the result on
     standard output without calling *note sys.exit(): 1394.:

          >>> from unittest import main
          >>> main(module='test_module', exit=False)

     The 'failfast', 'catchbreak' and 'buffer' parameters have the same
     effect as the same-name *note command-line options: 42a4.

     The 'warnings' argument specifies the *note warning filter: 8d2.
     that should be used while running the tests.  If it’s not
     specified, it will remain ‘None’ if a ‘-W’ option is passed to
     ‘python’ (see *note Warning control: 1ee0.), otherwise it will be
     set to ‘'default'’.

     Calling ‘main’ returns an object with the ‘result’ attribute that
     contains the result of the tests run as a *note
     unittest.TestResult: 11ab.

     Changed in version 3.1: The 'exit' parameter was added.

     Changed in version 3.2: The 'verbosity', 'failfast', 'catchbreak',
     'buffer' and 'warnings' parameters were added.

     Changed in version 3.4: The 'defaultTest' parameter was changed to
     also accept an iterable of test names.

* Menu:

* load_tests Protocol::


File: python.info,  Node: load_tests Protocol,  Up: Loading and running tests

5.26.5.13 load_tests Protocol
.............................

Added in version 3.2.

Modules or packages can customize how tests are loaded from them during
normal test runs or test discovery by implementing a function called
‘load_tests’.

If a test module defines ‘load_tests’ it will be called by *note
TestLoader.loadTestsFromModule(): 28f. with the following arguments:

     load_tests(loader, standard_tests, pattern)

where 'pattern' is passed straight through from ‘loadTestsFromModule’.
It defaults to ‘None’.

It should return a *note TestSuite: e26.

'loader' is the instance of *note TestLoader: 28e. doing the loading.
'standard_tests' are the tests that would be loaded by default from the
module.  It is common for test modules to only want to add or remove
tests from the standard set of tests.  The third argument is used when
loading packages as part of test discovery.

A typical ‘load_tests’ function that loads tests from a specific set of
*note TestCase: 451. classes may look like:

     test_cases = (TestCase1, TestCase2, TestCase3)

     def load_tests(loader, tests, pattern):
         suite = TestSuite()
         for test_class in test_cases:
             tests = loader.loadTestsFromTestCase(test_class)
             suite.addTests(tests)
         return suite

If discovery is started in a directory containing a package, either from
the command line or by calling *note TestLoader.discover(): 1020, then
the package ‘__init__.py’ will be checked for ‘load_tests’.  If that
function does not exist, discovery will recurse into the package as
though it were just another directory.  Otherwise, discovery of the
package’s tests will be left up to ‘load_tests’ which is called with the
following arguments:

     load_tests(loader, standard_tests, pattern)

This should return a *note TestSuite: e26. representing all the tests
from the package.  (‘standard_tests’ will only contain tests collected
from ‘__init__.py’.)

Because the pattern is passed into ‘load_tests’ the package is free to
continue (and potentially modify) test discovery.  A ‘do nothing’
‘load_tests’ function for a test package would look like:

     def load_tests(loader, standard_tests, pattern):
         # top level directory cached on loader instance
         this_dir = os.path.dirname(__file__)
         package_tests = loader.discover(start_dir=this_dir, pattern=pattern)
         standard_tests.addTests(package_tests)
         return standard_tests

Changed in version 3.5: Discovery no longer checks package names for
matching 'pattern' due to the impossibility of package names matching
the default pattern.


File: python.info,  Node: Class and Module Fixtures,  Next: Signal Handling,  Prev: Classes and functions,  Up: unittest — Unit testing framework

5.26.5.14 Class and Module Fixtures
...................................

Class and module level fixtures are implemented in *note TestSuite: e26.
When the test suite encounters a test from a new class then *note
tearDownClass(): 1382. from the previous class (if there is one) is
called, followed by *note setUpClass(): a5c. from the new class.

Similarly if a test is from a different module from the previous test
then ‘tearDownModule’ from the previous module is run, followed by
‘setUpModule’ from the new module.

After all the tests have run the final ‘tearDownClass’ and
‘tearDownModule’ are run.

Note that shared fixtures do not play well with [potential] features
like test parallelization and they break test isolation.  They should be
used with care.

The default ordering of tests created by the unittest test loaders is to
group all tests from the same modules and classes together.  This will
lead to ‘setUpClass’ / ‘setUpModule’ (etc) being called exactly once per
class and module.  If you randomize the order, so that tests from
different modules and classes are adjacent to each other, then these
shared fixture functions may be called multiple times in a single test
run.

Shared fixtures are not intended to work with suites with non-standard
ordering.  A ‘BaseTestSuite’ still exists for frameworks that don’t want
to support shared fixtures.

If there are any exceptions raised during one of the shared fixture
functions the test is reported as an error.  Because there is no
corresponding test instance an ‘_ErrorHolder’ object (that has the same
interface as a *note TestCase: 451.) is created to represent the error.
If you are just using the standard unittest test runner then this detail
doesn’t matter, but if you are a framework author it may be relevant.

* Menu:

* setUpClass and tearDownClass::
* setUpModule and tearDownModule::


File: python.info,  Node: setUpClass and tearDownClass,  Next: setUpModule and tearDownModule,  Up: Class and Module Fixtures

5.26.5.15 setUpClass and tearDownClass
......................................

These must be implemented as class methods:

     import unittest

     class Test(unittest.TestCase):
         @classmethod
         def setUpClass(cls):
             cls._connection = createExpensiveConnectionObject()

         @classmethod
         def tearDownClass(cls):
             cls._connection.destroy()

If you want the ‘setUpClass’ and ‘tearDownClass’ on base classes called
then you must call up to them yourself.  The implementations in *note
TestCase: 451. are empty.

If an exception is raised during a ‘setUpClass’ then the tests in the
class are not run and the ‘tearDownClass’ is not run.  Skipped classes
will not have ‘setUpClass’ or ‘tearDownClass’ run.  If the exception is
a *note SkipTest: 101f. exception then the class will be reported as
having been skipped instead of as an error.


File: python.info,  Node: setUpModule and tearDownModule,  Prev: setUpClass and tearDownClass,  Up: Class and Module Fixtures

5.26.5.16 setUpModule and tearDownModule
........................................

These should be implemented as functions:

     def setUpModule():
         createConnection()

     def tearDownModule():
         closeConnection()

If an exception is raised in a ‘setUpModule’ then none of the tests in
the module will be run and the ‘tearDownModule’ will not be run.  If the
exception is a *note SkipTest: 101f. exception then the module will be
reported as having been skipped instead of as an error.

To add cleanup code that must be run even in the case of an exception,
use ‘addModuleCleanup’:

 -- Function: unittest.addModuleCleanup (function, /, *args, **kwargs)

     Add a function to be called after *note tearDownModule(): 1381. to
     cleanup resources used during the test class.  Functions will be
     called in reverse order to the order they are added (LIFO).  They
     are called with any arguments and keyword arguments passed into
     *note addModuleCleanup(): a59. when they are added.

     If *note setUpModule(): a5b. fails, meaning that *note
     tearDownModule(): 1381. is not called, then any cleanup functions
     added will still be called.

     Added in version 3.8.

 -- Function: unittest.enterModuleContext (cm)

     Enter the supplied *note context manager: 5d7.  If successful, also
     add its *note __exit__(): 1349. method as a cleanup function by
     *note addModuleCleanup(): a59. and return the result of the *note
     __enter__(): 5cb. method.

     Added in version 3.11.

 -- Function: unittest.doModuleCleanups ()

     This function is called unconditionally after *note
     tearDownModule(): 1381, or after *note setUpModule(): a5b. if
     ‘setUpModule()’ raises an exception.

     It is responsible for calling all the cleanup functions added by
     *note addModuleCleanup(): a59.  If you need cleanup functions to be
     called 'prior' to *note tearDownModule(): 1381. then you can call
     ‘doModuleCleanups()’ yourself.

     ‘doModuleCleanups()’ pops methods off the stack of cleanup
     functions one at a time, so it can be called at any time.

     Added in version 3.8.


File: python.info,  Node: Signal Handling,  Prev: Class and Module Fixtures,  Up: unittest — Unit testing framework

5.26.5.17 Signal Handling
.........................

Added in version 3.2.

The *note -c/-catch: 137d. command-line option to unittest, along with
the ‘catchbreak’ parameter to *note unittest.main(): 101e, provide more
friendly handling of control-C during a test run.  With catch break
behavior enabled control-C will allow the currently running test to
complete, and the test run will then end and report all the results so
far.  A second control-c will raise a *note KeyboardInterrupt: 9dc. in
the usual way.

The control-c handling signal handler attempts to remain compatible with
code or tests that install their own *note signal.SIGINT: 84a. handler.
If the ‘unittest’ handler is called but 'isn’t' the installed
‘signal.SIGINT’ handler, i.e.  it has been replaced by the system under
test and delegated to, then it calls the default handler.  This will
normally be the expected behavior by code that replaces an installed
handler and delegates to it.  For individual tests that need ‘unittest’
control-c handling disabled the *note removeHandler(): 137e. decorator
can be used.

There are a few utility functions for framework authors to enable
control-c handling functionality within test frameworks.

 -- Function: unittest.installHandler ()

     Install the control-c handler.  When a *note signal.SIGINT: 84a. is
     received (usually in response to the user pressing control-c) all
     registered results have *note stop(): 42e7. called.

 -- Function: unittest.registerResult (result)

     Register a *note TestResult: 11ab. object for control-c handling.
     Registering a result stores a weak reference to it, so it doesn’t
     prevent the result from being garbage collected.

     Registering a *note TestResult: 11ab. object has no side-effects if
     control-c handling is not enabled, so test frameworks can
     unconditionally register all results they create independently of
     whether or not handling is enabled.

 -- Function: unittest.removeResult (result)

     Remove a registered result.  Once a result has been removed then
     *note stop(): 42e7. will no longer be called on that result object
     in response to a control-c.

 -- Function: unittest.removeHandler (function=None)

     When called without arguments this function removes the control-c
     handler if it has been installed.  This function can also be used
     as a test decorator to temporarily remove the handler while the
     test is being executed:

          @unittest.removeHandler
          def test_signal_handling(self):
              ...


File: python.info,  Node: unittest mock — mock object library,  Next: unittest mock — getting started,  Prev: unittest — Unit testing framework,  Up: Development Tools

5.26.6 ‘unittest.mock’ — mock object library
--------------------------------------------

Added in version 3.3.

'Source code:' Lib/unittest/mock.py(1)

__________________________________________________________________

‘unittest.mock’ is a library for testing in Python.  It allows you to
replace parts of your system under test with mock objects and make
assertions about how they have been used.

‘unittest.mock’ provides a core *note Mock: a58. class removing the need
to create a host of stubs throughout your test suite.  After performing
an action, you can make assertions about which methods / attributes were
used and arguments they were called with.  You can also specify return
values and set needed attributes in the normal way.

Additionally, mock provides a *note patch(): ec6. decorator that handles
patching module and class level attributes within the scope of a test,
along with *note sentinel: bbe. for creating unique objects.  See the
*note quick guide: 42fd. for some examples of how to use *note Mock:
a58, *note MagicMock: ec3. and ‘patch()’.

Mock is designed for use with *note unittest: 106. and is based on the
‘action -> assertion’ pattern instead of ‘record -> replay’ used by many
mocking frameworks.

There is a backport of ‘unittest.mock’ for earlier versions of Python,
available as mock(2) on PyPI.

* Menu:

* Quick Guide::
* The Mock Class::
* The patchers::
* MagicMock and magic method support::
* Helpers::
* Order of precedence of side_effect, return_value and wraps: Order of precedence of side_effect return_value and wraps.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/unittest/mock.py

   (2) https://pypi.org/project/mock/


File: python.info,  Node: Quick Guide,  Next: The Mock Class,  Up: unittest mock — mock object library

5.26.6.1 Quick Guide
....................

*note Mock: a58. and *note MagicMock: ec3. objects create all attributes
and methods as you access them and store details of how they have been
used.  You can configure them, to specify return values or limit what
attributes are available, and then make assertions about how they have
been used:

     >>> from unittest.mock import MagicMock
     >>> thing = ProductionClass()
     >>> thing.method = MagicMock(return_value=3)
     >>> thing.method(3, 4, 5, key='value')
     3
     >>> thing.method.assert_called_with(3, 4, 5, key='value')

*note side_effect: 42fe. allows you to perform side effects, including
raising an exception when a mock is called:

     >>> from unittest.mock import Mock
     >>> mock = Mock(side_effect=KeyError('foo'))
     >>> mock()
     Traceback (most recent call last):
      ...
     KeyError: 'foo'

     >>> values = {'a': 1, 'b': 2, 'c': 3}
     >>> def side_effect(arg):
     ...     return values[arg]
     ...
     >>> mock.side_effect = side_effect
     >>> mock('a'), mock('b'), mock('c')
     (1, 2, 3)
     >>> mock.side_effect = [5, 4, 3, 2, 1]
     >>> mock(), mock(), mock()
     (5, 4, 3)

Mock has many other ways you can configure it and control its behaviour.
For example the 'spec' argument configures the mock to take its
specification from another object.  Attempting to access attributes or
methods on the mock that don’t exist on the spec will fail with an *note
AttributeError: 34e.

The *note patch(): ec6. decorator / context manager makes it easy to
mock classes or objects in a module under test.  The object you specify
will be replaced with a mock (or other object) during the test and
restored when the test ends:

     >>> from unittest.mock import patch
     >>> @patch('module.ClassName2')
     ... @patch('module.ClassName1')
     ... def test(MockClass1, MockClass2):
     ...     module.ClassName1()
     ...     module.ClassName2()
     ...     assert MockClass1 is module.ClassName1
     ...     assert MockClass2 is module.ClassName2
     ...     assert MockClass1.called
     ...     assert MockClass2.called
     ...
     >>> test()

     Note: When you nest patch decorators the mocks are passed in to the
     decorated function in the same order they applied (the normal
     'Python' order that decorators are applied).  This means from the
     bottom up, so in the example above the mock for ‘module.ClassName1’
     is passed in first.

     With *note patch(): ec6. it matters that you patch objects in the
     namespace where they are looked up.  This is normally
     straightforward, but for a quick guide read *note where to patch:
     42ff.

As well as a decorator *note patch(): ec6. can be used as a context
manager in a with statement:

     >>> with patch.object(ProductionClass, 'method', return_value=None) as mock_method:
     ...     thing = ProductionClass()
     ...     thing.method(1, 2, 3)
     ...
     >>> mock_method.assert_called_once_with(1, 2, 3)

There is also *note patch.dict(): 1b83. for setting values in a
dictionary just during a scope and restoring the dictionary to its
original state when the test ends:

     >>> foo = {'key': 'value'}
     >>> original = foo.copy()
     >>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
     ...     assert foo == {'newkey': 'newvalue'}
     ...
     >>> assert foo == original

Mock supports the mocking of Python *note magic methods: 4300.  The
easiest way of using magic methods is with the *note MagicMock: ec3.
class.  It allows you to do things like:

     >>> mock = MagicMock()
     >>> mock.__str__.return_value = 'foobarbaz'
     >>> str(mock)
     'foobarbaz'
     >>> mock.__str__.assert_called_with()

Mock allows you to assign functions (or other Mock instances) to magic
methods and they will be called appropriately.  The *note MagicMock:
ec3. class is just a Mock variant that has all of the magic methods
pre-created for you (well, all the useful ones anyway).

The following is an example of using magic methods with the ordinary
Mock class:

     >>> mock = Mock()
     >>> mock.__str__ = Mock(return_value='wheeeeee')
     >>> str(mock)
     'wheeeeee'

For ensuring that the mock objects in your tests have the same api as
the objects they are replacing, you can use *note auto-speccing: 4301.
Auto-speccing can be done through the 'autospec' argument to patch, or
the *note create_autospec(): 1712. function.  Auto-speccing creates mock
objects that have the same attributes and methods as the objects they
are replacing, and any functions and methods (including constructors)
have the same call signature as the real object.

This ensures that your mocks will fail in the same way as your
production code if they are used incorrectly:

     >>> from unittest.mock import create_autospec
     >>> def function(a, b, c):
     ...     pass
     ...
     >>> mock_function = create_autospec(function, return_value='fishy')
     >>> mock_function(1, 2, 3)
     'fishy'
     >>> mock_function.assert_called_once_with(1, 2, 3)
     >>> mock_function('wrong arguments')
     Traceback (most recent call last):
      ...
     TypeError: missing a required argument: 'b'

*note create_autospec(): 1712. can also be used on classes, where it
copies the signature of the ‘__init__’ method, and on callable objects
where it copies the signature of the ‘__call__’ method.


File: python.info,  Node: The Mock Class,  Next: The patchers,  Prev: Quick Guide,  Up: unittest mock — mock object library

5.26.6.2 The Mock Class
.......................

*note Mock: a58. is a flexible mock object intended to replace the use
of stubs and test doubles throughout your code.  Mocks are callable and
create attributes as new mocks when you access them (1).  Accessing the
same attribute will always return the same mock.  Mocks record how you
use them, allowing you to make assertions about what your code has done
to them.

*note MagicMock: ec3. is a subclass of *note Mock: a58. with all the
magic methods pre-created and ready to use.  There are also non-callable
variants, useful when you are mocking out objects that aren’t callable:
*note NonCallableMock: 4303. and *note NonCallableMagicMock: 4304.

The *note patch(): ec6. decorators makes it easy to temporarily replace
classes in a particular module with a *note Mock: a58. object.  By
default ‘patch()’ will create a *note MagicMock: ec3. for you.  You can
specify an alternative class of ‘Mock’ using the 'new_callable' argument
to ‘patch()’.

 -- Class: unittest.mock.Mock (spec=None, side_effect=None,
          return_value=DEFAULT, wraps=None, name=None, spec_set=None,
          unsafe=False, **kwargs)

     Create a new ‘Mock’ object.  ‘Mock’ takes several optional
     arguments that specify the behaviour of the Mock object:

        * 'spec': This can be either a list of strings or an existing
          object (a class or instance) that acts as the specification
          for the mock object.  If you pass in an object then a list of
          strings is formed by calling dir on the object (excluding
          unsupported magic attributes and methods).  Accessing any
          attribute not in this list will raise an *note AttributeError:
          34e.

          If 'spec' is an object (rather than a list of strings) then
          *note __class__: 14fc. returns the class of the spec object.
          This allows mocks to pass *note isinstance(): 445. tests.

        * 'spec_set': A stricter variant of 'spec'.  If used, attempting
          to 'set' or get an attribute on the mock that isn’t on the
          object passed as 'spec_set' will raise an *note
          AttributeError: 34e.

        * 'side_effect': A function to be called whenever the Mock is
          called.  See the *note side_effect: 42fe. attribute.  Useful
          for raising exceptions or dynamically changing return values.
          The function is called with the same arguments as the mock,
          and unless it returns *note DEFAULT: 4305, the return value of
          this function is used as the return value.

          Alternatively 'side_effect' can be an exception class or
          instance.  In this case the exception will be raised when the
          mock is called.

          If 'side_effect' is an iterable then each call to the mock
          will return the next value from the iterable.

          A 'side_effect' can be cleared by setting it to ‘None’.

        * 'return_value': The value returned when the mock is called.
          By default this is a new Mock (created on first access).  See
          the *note return_value: 4306. attribute.

        * 'unsafe': By default, accessing any attribute whose name
          starts with 'assert', 'assret', 'asert', 'aseert' or 'assrt'
          will raise an *note AttributeError: 34e.  Passing
          ‘unsafe=True’ will allow access to these attributes.

          Added in version 3.5.

        * 'wraps': Item for the mock object to wrap.  If 'wraps' is not
          ‘None’ then calling the Mock will pass the call through to the
          wrapped object (returning the real result).  Attribute access
          on the mock will return a Mock object that wraps the
          corresponding attribute of the wrapped object (so attempting
          to access an attribute that doesn’t exist will raise an *note
          AttributeError: 34e.).

          If the mock has an explicit 'return_value' set then calls are
          not passed to the wrapped object and the 'return_value' is
          returned instead.

        * 'name': If the mock has a name then it will be used in the
          repr of the mock.  This can be useful for debugging.  The name
          is propagated to child mocks.

     Mocks can also be called with arbitrary keyword arguments.  These
     will be used to set attributes on the mock after it is created.
     See the *note configure_mock(): 4307. method for details.

      -- Method: assert_called ()

          Assert that the mock was called at least once.

               >>> mock = Mock()
               >>> mock.method()
               <Mock name='mock.method()' id='...'>
               >>> mock.method.assert_called()

          Added in version 3.6.

      -- Method: assert_called_once ()

          Assert that the mock was called exactly once.

               >>> mock = Mock()
               >>> mock.method()
               <Mock name='mock.method()' id='...'>
               >>> mock.method.assert_called_once()
               >>> mock.method()
               <Mock name='mock.method()' id='...'>
               >>> mock.method.assert_called_once()
               Traceback (most recent call last):
               ...
               AssertionError: Expected 'method' to have been called once. Called 2 times.
               Calls: [call(), call()].

          Added in version 3.6.

      -- Method: assert_called_with (*args, **kwargs)

          This method is a convenient way of asserting that the last
          call has been made in a particular way:

               >>> mock = Mock()
               >>> mock.method(1, 2, 3, test='wow')
               <Mock name='mock.method()' id='...'>
               >>> mock.method.assert_called_with(1, 2, 3, test='wow')

      -- Method: assert_called_once_with (*args, **kwargs)

          Assert that the mock was called exactly once and that call was
          with the specified arguments.

               >>> mock = Mock(return_value=None)
               >>> mock('foo', bar='baz')
               >>> mock.assert_called_once_with('foo', bar='baz')
               >>> mock('other', bar='values')
               >>> mock.assert_called_once_with('other', bar='values')
               Traceback (most recent call last):
                 ...
               AssertionError: Expected 'mock' to be called once. Called 2 times.
               Calls: [call('foo', bar='baz'), call('other', bar='values')].

      -- Method: assert_any_call (*args, **kwargs)

          assert the mock has been called with the specified arguments.

          The assert passes if the mock has 'ever' been called, unlike
          *note assert_called_with(): 1bb2. and *note
          assert_called_once_with(): 4308. that only pass if the call is
          the most recent one, and in the case of
          ‘assert_called_once_with()’ it must also be the only call.

               >>> mock = Mock(return_value=None)
               >>> mock(1, 2, arg='thing')
               >>> mock('some', 'thing', 'else')
               >>> mock.assert_any_call(1, 2, arg='thing')

      -- Method: assert_has_calls (calls, any_order=False)

          assert the mock has been called with the specified calls.  The
          *note mock_calls: 430a. list is checked for the calls.

          If 'any_order' is false then the calls must be sequential.
          There can be extra calls before or after the specified calls.

          If 'any_order' is true then the calls can be in any order, but
          they must all appear in *note mock_calls: 430a.

               >>> mock = Mock(return_value=None)
               >>> mock(1)
               >>> mock(2)
               >>> mock(3)
               >>> mock(4)
               >>> calls = [call(2), call(3)]
               >>> mock.assert_has_calls(calls)
               >>> calls = [call(4), call(2), call(3)]
               >>> mock.assert_has_calls(calls, any_order=True)

      -- Method: assert_not_called ()

          Assert the mock was never called.

               >>> m = Mock()
               >>> m.hello.assert_not_called()
               >>> obj = m.hello()
               >>> m.hello.assert_not_called()
               Traceback (most recent call last):
                 ...
               AssertionError: Expected 'hello' to not have been called. Called 1 times.
               Calls: [call()].

          Added in version 3.5.

      -- Method: reset_mock (*, return_value=False, side_effect=False)

          The reset_mock method resets all the call attributes on a mock
          object:

               >>> mock = Mock(return_value=None)
               >>> mock('hello')
               >>> mock.called
               True
               >>> mock.reset_mock()
               >>> mock.called
               False

          This can be useful where you want to make a series of
          assertions that reuse the same object.

          'return_value' parameter when set to ‘True’ resets *note
          return_value: 4306.:

               >>> mock = Mock(return_value=5)
               >>> mock('hello')
               5
               >>> mock.reset_mock(return_value=True)
               >>> mock('hello')
               <Mock name='mock()' id='...'>

          'side_effect' parameter when set to ‘True’ resets *note
          side_effect: 42fe.:

               >>> mock = Mock(side_effect=ValueError)
               >>> mock('hello')
               Traceback (most recent call last):
                 ...
               ValueError
               >>> mock.reset_mock(side_effect=True)
               >>> mock('hello')
               <Mock name='mock()' id='...'>

          Note that ‘reset_mock()’ 'doesn’t' clear the *note
          return_value: 4306, *note side_effect: 42fe. or any child
          attributes you have set using normal assignment by default.

          Child mocks are reset as well.

          Changed in version 3.6: Added two keyword-only arguments to
          the reset_mock function.

      -- Method: mock_add_spec (spec, spec_set=False)

          Add a spec to a mock.  'spec' can either be an object or a
          list of strings.  Only attributes on the 'spec' can be fetched
          as attributes from the mock.

          If 'spec_set' is true then only attributes on the spec can be
          set.

      -- Method: attach_mock (mock, attribute)

          Attach a mock as an attribute of this one, replacing its name
          and parent.  Calls to the attached mock will be recorded in
          the *note method_calls: 430c. and *note mock_calls: 430a.
          attributes of this one.

      -- Method: configure_mock (**kwargs)

          Set attributes on the mock through keyword arguments.

          Attributes plus return values and side effects can be set on
          child mocks using standard dot notation and unpacking a
          dictionary in the method call:

               >>> mock = Mock()
               >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
               >>> mock.configure_mock(**attrs)
               >>> mock.method()
               3
               >>> mock.other()
               Traceback (most recent call last):
                 ...
               KeyError

          The same thing can be achieved in the constructor call to
          mocks:

               >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
               >>> mock = Mock(some_attribute='eggs', **attrs)
               >>> mock.some_attribute
               'eggs'
               >>> mock.method()
               3
               >>> mock.other()
               Traceback (most recent call last):
                 ...
               KeyError

          ‘configure_mock()’ exists to make it easier to do
          configuration after the mock has been created.

      -- Method: __dir__ ()

          ‘Mock’ objects limit the results of ‘dir(some_mock)’ to useful
          results.  For mocks with a 'spec' this includes all the
          permitted attributes for the mock.

          See *note FILTER_DIR: 430e. for what this filtering does, and
          how to switch it off.

      -- Method: _get_child_mock (**kw)

          Create the child mocks for attributes and return value.  By
          default child mocks will be the same type as the parent.
          Subclasses of Mock may want to override this to customize the
          way child mocks are made.

          For non-callable mocks the callable variant will be used
          (rather than any custom subclass).

      -- Attribute: called

          A boolean representing whether or not the mock object has been
          called:

               >>> mock = Mock(return_value=None)
               >>> mock.called
               False
               >>> mock()
               >>> mock.called
               True

      -- Attribute: call_count

          An integer telling you how many times the mock object has been
          called:

               >>> mock = Mock(return_value=None)
               >>> mock.call_count
               0
               >>> mock()
               >>> mock()
               >>> mock.call_count
               2

      -- Attribute: return_value

          Set this to configure the value returned by calling the mock:

               >>> mock = Mock()
               >>> mock.return_value = 'fish'
               >>> mock()
               'fish'

          The default return value is a mock object and you can
          configure it in the normal way:

               >>> mock = Mock()
               >>> mock.return_value.attribute = sentinel.Attribute
               >>> mock.return_value()
               <Mock name='mock()()' id='...'>
               >>> mock.return_value.assert_called_with()

          *note return_value: 4306. can also be set in the constructor:

               >>> mock = Mock(return_value=3)
               >>> mock.return_value
               3
               >>> mock()
               3

      -- Attribute: side_effect

          This can either be a function to be called when the mock is
          called, an iterable or an exception (class or instance) to be
          raised.

          If you pass in a function it will be called with same
          arguments as the mock and unless the function returns the
          *note DEFAULT: 4305. singleton the call to the mock will then
          return whatever the function returns.  If the function returns
          ‘DEFAULT’ then the mock will return its normal value (from the
          *note return_value: 4306.).

          If you pass in an iterable, it is used to retrieve an iterator
          which must yield a value on every call.  This value can either
          be an exception instance to be raised, or a value to be
          returned from the call to the mock (*note DEFAULT: 4305.
          handling is identical to the function case).

          An example of a mock that raises an exception (to test
          exception handling of an API):

               >>> mock = Mock()
               >>> mock.side_effect = Exception('Boom!')
               >>> mock()
               Traceback (most recent call last):
                 ...
               Exception: Boom!

          Using *note side_effect: 42fe. to return a sequence of values:

               >>> mock = Mock()
               >>> mock.side_effect = [3, 2, 1]
               >>> mock(), mock(), mock()
               (3, 2, 1)

          Using a callable:

               >>> mock = Mock(return_value=3)
               >>> def side_effect(*args, **kwargs):
               ...     return DEFAULT
               ...
               >>> mock.side_effect = side_effect
               >>> mock()
               3

          *note side_effect: 42fe. can be set in the constructor.
          Here’s an example that adds one to the value the mock is
          called with and returns it:

               >>> side_effect = lambda value: value + 1
               >>> mock = Mock(side_effect=side_effect)
               >>> mock(3)
               4
               >>> mock(-8)
               -7

          Setting *note side_effect: 42fe. to ‘None’ clears it:

               >>> m = Mock(side_effect=KeyError, return_value=3)
               >>> m()
               Traceback (most recent call last):
                ...
               KeyError
               >>> m.side_effect = None
               >>> m()
               3

      -- Attribute: call_args

          This is either ‘None’ (if the mock hasn’t been called), or the
          arguments that the mock was last called with.  This will be in
          the form of a tuple: the first member, which can also be
          accessed through the ‘args’ property, is any positional
          arguments the mock was called with (or an empty tuple) and the
          second member, which can also be accessed through the ‘kwargs’
          property, is any keyword arguments (or an empty dictionary).

               >>> mock = Mock(return_value=None)
               >>> print(mock.call_args)
               None
               >>> mock()
               >>> mock.call_args
               call()
               >>> mock.call_args == ()
               True
               >>> mock(3, 4)
               >>> mock.call_args
               call(3, 4)
               >>> mock.call_args == ((3, 4),)
               True
               >>> mock.call_args.args
               (3, 4)
               >>> mock.call_args.kwargs
               {}
               >>> mock(3, 4, 5, key='fish', next='w00t!')
               >>> mock.call_args
               call(3, 4, 5, key='fish', next='w00t!')
               >>> mock.call_args.args
               (3, 4, 5)
               >>> mock.call_args.kwargs
               {'key': 'fish', 'next': 'w00t!'}

          *note call_args: 1b12, along with members of the lists *note
          call_args_list: 4311, *note method_calls: 430c. and *note
          mock_calls: 430a. are *note call: 1b5e. objects.  These are
          tuples, so they can be unpacked to get at the individual
          arguments and make more complex assertions.  See *note calls
          as tuples: 4312.

          Changed in version 3.8: Added ‘args’ and ‘kwargs’ properties.

      -- Attribute: call_args_list

          This is a list of all the calls made to the mock object in
          sequence (so the length of the list is the number of times it
          has been called).  Before any calls have been made it is an
          empty list.  The *note call: 1b5e. object can be used for
          conveniently constructing lists of calls to compare with *note
          call_args_list: 4311.

               >>> mock = Mock(return_value=None)
               >>> mock()
               >>> mock(3, 4)
               >>> mock(key='fish', next='w00t!')
               >>> mock.call_args_list
               [call(), call(3, 4), call(key='fish', next='w00t!')]
               >>> expected = [(), ((3, 4),), ({'key': 'fish', 'next': 'w00t!'},)]
               >>> mock.call_args_list == expected
               True

          Members of *note call_args_list: 4311. are *note call: 1b5e.
          objects.  These can be unpacked as tuples to get at the
          individual arguments.  See *note calls as tuples: 4312.

      -- Attribute: method_calls

          As well as tracking calls to themselves, mocks also track
          calls to methods and attributes, and 'their' methods and
          attributes:

               >>> mock = Mock()
               >>> mock.method()
               <Mock name='mock.method()' id='...'>
               >>> mock.property.method.attribute()
               <Mock name='mock.property.method.attribute()' id='...'>
               >>> mock.method_calls
               [call.method(), call.property.method.attribute()]

          Members of *note method_calls: 430c. are *note call: 1b5e.
          objects.  These can be unpacked as tuples to get at the
          individual arguments.  See *note calls as tuples: 4312.

      -- Attribute: mock_calls

          *note mock_calls: 430a. records 'all' calls to the mock
          object, its methods, magic methods 'and' return value mocks.

               >>> mock = MagicMock()
               >>> result = mock(1, 2, 3)
               >>> mock.first(a=3)
               <MagicMock name='mock.first()' id='...'>
               >>> mock.second()
               <MagicMock name='mock.second()' id='...'>
               >>> int(mock)
               1
               >>> result(1)
               <MagicMock name='mock()()' id='...'>
               >>> expected = [call(1, 2, 3), call.first(a=3), call.second(),
               ... call.__int__(), call()(1)]
               >>> mock.mock_calls == expected
               True

          Members of *note mock_calls: 430a. are *note call: 1b5e.
          objects.  These can be unpacked as tuples to get at the
          individual arguments.  See *note calls as tuples: 4312.

               Note: The way *note mock_calls: 430a. are recorded means
               that where nested calls are made, the parameters of
               ancestor calls are not recorded and so will always
               compare equal:

                    >>> mock = MagicMock()
                    >>> mock.top(a=3).bottom()
                    <MagicMock name='mock.top().bottom()' id='...'>
                    >>> mock.mock_calls
                    [call.top(a=3), call.top().bottom()]
                    >>> mock.mock_calls[-1] == call.top(a=-1).bottom()
                    True

      -- Attribute: __class__

          Normally the ‘__class__’ attribute of an object will return
          its type.  For a mock object with a ‘spec’, ‘__class__’
          returns the spec class instead.  This allows mock objects to
          pass *note isinstance(): 445. tests for the object they are
          replacing / masquerading as:

               >>> mock = Mock(spec=3)
               >>> isinstance(mock, int)
               True

          ‘__class__’ is assignable to, this allows a mock to pass an
          *note isinstance(): 445. check without forcing you to use a
          spec:

               >>> mock = Mock()
               >>> mock.__class__ = dict
               >>> isinstance(mock, dict)
               True

 -- Class: unittest.mock.NonCallableMock (spec=None, wraps=None,
          name=None, spec_set=None, **kwargs)

     A non-callable version of *note Mock: a58.  The constructor
     parameters have the same meaning of ‘Mock’, with the exception of
     'return_value' and 'side_effect' which have no meaning on a
     non-callable mock.

Mock objects that use a class or an instance as a ‘spec’ or ‘spec_set’
are able to pass *note isinstance(): 445. tests:

     >>> mock = Mock(spec=SomeClass)
     >>> isinstance(mock, SomeClass)
     True
     >>> mock = Mock(spec_set=SomeClass())
     >>> isinstance(mock, SomeClass)
     True

The *note Mock: a58. classes have support for mocking magic methods.
See *note magic methods: 4300. for the full details.

The mock classes and the *note patch(): ec6. decorators all take
arbitrary keyword arguments for configuration.  For the ‘patch()’
decorators the keywords are passed to the constructor of the mock being
created.  The keyword arguments are for configuring attributes of the
mock:

     >>> m = MagicMock(attribute=3, other='fish')
     >>> m.attribute
     3
     >>> m.other
     'fish'

The return value and side effect of child mocks can be set in the same
way, using dotted notation.  As you can’t use dotted names directly in a
call you have to create a dictionary and unpack it using ‘**’:

     >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
     >>> mock = Mock(some_attribute='eggs', **attrs)
     >>> mock.some_attribute
     'eggs'
     >>> mock.method()
     3
     >>> mock.other()
     Traceback (most recent call last):
       ...
     KeyError

A callable mock which was created with a 'spec' (or a 'spec_set') will
introspect the specification object’s signature when matching calls to
the mock.  Therefore, it can match the actual call’s arguments
regardless of whether they were passed positionally or by name:

     >>> def f(a, b, c): pass
     ...
     >>> mock = Mock(spec=f)
     >>> mock(1, 2, c=3)
     <Mock name='mock()' id='140161580456576'>
     >>> mock.assert_called_with(1, 2, 3)
     >>> mock.assert_called_with(a=1, b=2, c=3)

This applies to *note assert_called_with(): 1bb2, *note
assert_called_once_with(): 4308, *note assert_has_calls(): 17ba. and
*note assert_any_call(): 4309.  When *note Autospeccing: 4301, it will
also apply to method calls on the mock object.

Changed in version 3.4: Added signature introspection on specced and
autospecced mock objects.

 -- Class: unittest.mock.PropertyMock (*args, **kwargs)

     A mock intended to be used as a *note property: 194, or other *note
     descriptor: 1677, on a class.  ‘PropertyMock’ provides *note
     __get__(): 1537. and *note __set__(): 211b. methods so you can
     specify a return value when it is fetched.

     Fetching a ‘PropertyMock’ instance from an object calls the mock,
     with no args.  Setting it calls the mock with the value being set.

          >>> class Foo:
          ...     @property
          ...     def foo(self):
          ...         return 'something'
          ...     @foo.setter
          ...     def foo(self, value):
          ...         pass
          ...
          >>> with patch('__main__.Foo.foo', new_callable=PropertyMock) as mock_foo:
          ...     mock_foo.return_value = 'mockity-mock'
          ...     this_foo = Foo()
          ...     print(this_foo.foo)
          ...     this_foo.foo = 6
          ...
          mockity-mock
          >>> mock_foo.mock_calls
          [call(), call(6)]

Because of the way mock attributes are stored you can’t directly attach
a *note PropertyMock: 4314. to a mock object.  Instead you can attach it
to the mock type object:

     >>> m = MagicMock()
     >>> p = PropertyMock(return_value=3)
     >>> type(m).foo = p
     >>> m.foo
     3
     >>> p.assert_called_once_with()

     Caution: If an *note AttributeError: 34e. is raised by *note
     PropertyMock: 4314, it will be interpreted as a missing descriptor
     and *note __getattr__(): 4d6. will be called on the parent mock:

          >>> m = MagicMock()
          >>> no_attribute = PropertyMock(side_effect=AttributeError)
          >>> type(m).my_property = no_attribute
          >>> m.my_property
          <MagicMock name='mock.my_property' id='140165240345424'>

     See *note __getattr__(): 4d6. for details.

 -- Class: unittest.mock.AsyncMock (spec=None, side_effect=None,
          return_value=DEFAULT, wraps=None, name=None, spec_set=None,
          unsafe=False, **kwargs)

     An asynchronous version of *note MagicMock: ec3.  The ‘AsyncMock’
     object will behave so the object is recognized as an async
     function, and the result of a call is an awaitable.

          >>> mock = AsyncMock()
          >>> asyncio.iscoroutinefunction(mock)
          True
          >>> inspect.isawaitable(mock())
          True

     The result of ‘mock()’ is an async function which will have the
     outcome of ‘side_effect’ or ‘return_value’ after it has been
     awaited:

        - if ‘side_effect’ is a function, the async function will return
          the result of that function,

        - if ‘side_effect’ is an exception, the async function will
          raise the exception,

        - if ‘side_effect’ is an iterable, the async function will
          return the next value of the iterable, however, if the
          sequence of result is exhausted, ‘StopAsyncIteration’ is
          raised immediately,

        - if ‘side_effect’ is not defined, the async function will
          return the value defined by ‘return_value’, hence, by default,
          the async function returns a new ‘AsyncMock’ object.

     Setting the 'spec' of a *note Mock: a58. or *note MagicMock: ec3.
     to an async function will result in a coroutine object being
     returned after calling.

          >>> async def async_func(): pass
          ...
          >>> mock = MagicMock(async_func)
          >>> mock
          <MagicMock spec='function' id='...'>
          >>> mock()
          <coroutine object AsyncMockMixin._mock_call at ...>

     Setting the 'spec' of a *note Mock: a58, *note MagicMock: ec3, or
     ‘AsyncMock’ to a class with asynchronous and synchronous functions
     will automatically detect the synchronous functions and set them as
     ‘MagicMock’ (if the parent mock is ‘AsyncMock’ or ‘MagicMock’) or
     ‘Mock’ (if the parent mock is ‘Mock’).  All asynchronous functions
     will be ‘AsyncMock’.

          >>> class ExampleClass:
          ...     def sync_foo():
          ...         pass
          ...     async def async_foo():
          ...         pass
          ...
          >>> a_mock = AsyncMock(ExampleClass)
          >>> a_mock.sync_foo
          <MagicMock name='mock.sync_foo' id='...'>
          >>> a_mock.async_foo
          <AsyncMock name='mock.async_foo' id='...'>
          >>> mock = Mock(ExampleClass)
          >>> mock.sync_foo
          <Mock name='mock.sync_foo' id='...'>
          >>> mock.async_foo
          <AsyncMock name='mock.async_foo' id='...'>

     Added in version 3.8.

      -- Method: assert_awaited ()

          Assert that the mock was awaited at least once.  Note that
          this is separate from the object having been called, the
          ‘await’ keyword must be used:

               >>> mock = AsyncMock()
               >>> async def main(coroutine_mock):
               ...     await coroutine_mock
               ...
               >>> coroutine_mock = mock()
               >>> mock.called
               True
               >>> mock.assert_awaited()
               Traceback (most recent call last):
               ...
               AssertionError: Expected mock to have been awaited.
               >>> asyncio.run(main(coroutine_mock))
               >>> mock.assert_awaited()

      -- Method: assert_awaited_once ()

          Assert that the mock was awaited exactly once.

               >>> mock = AsyncMock()
               >>> async def main():
               ...     await mock()
               ...
               >>> asyncio.run(main())
               >>> mock.assert_awaited_once()
               >>> asyncio.run(main())
               >>> mock.assert_awaited_once()
               Traceback (most recent call last):
               ...
               AssertionError: Expected mock to have been awaited once. Awaited 2 times.

      -- Method: assert_awaited_with (*args, **kwargs)

          Assert that the last await was with the specified arguments.

               >>> mock = AsyncMock()
               >>> async def main(*args, **kwargs):
               ...     await mock(*args, **kwargs)
               ...
               >>> asyncio.run(main('foo', bar='bar'))
               >>> mock.assert_awaited_with('foo', bar='bar')
               >>> mock.assert_awaited_with('other')
               Traceback (most recent call last):
               ...
               AssertionError: expected await not found.
               Expected: mock('other')
               Actual: mock('foo', bar='bar')

      -- Method: assert_awaited_once_with (*args, **kwargs)

          Assert that the mock was awaited exactly once and with the
          specified arguments.

               >>> mock = AsyncMock()
               >>> async def main(*args, **kwargs):
               ...     await mock(*args, **kwargs)
               ...
               >>> asyncio.run(main('foo', bar='bar'))
               >>> mock.assert_awaited_once_with('foo', bar='bar')
               >>> asyncio.run(main('foo', bar='bar'))
               >>> mock.assert_awaited_once_with('foo', bar='bar')
               Traceback (most recent call last):
               ...
               AssertionError: Expected mock to have been awaited once. Awaited 2 times.

      -- Method: assert_any_await (*args, **kwargs)

          Assert the mock has ever been awaited with the specified
          arguments.

               >>> mock = AsyncMock()
               >>> async def main(*args, **kwargs):
               ...     await mock(*args, **kwargs)
               ...
               >>> asyncio.run(main('foo', bar='bar'))
               >>> asyncio.run(main('hello'))
               >>> mock.assert_any_await('foo', bar='bar')
               >>> mock.assert_any_await('other')
               Traceback (most recent call last):
               ...
               AssertionError: mock('other') await not found

      -- Method: assert_has_awaits (calls, any_order=False)

          Assert the mock has been awaited with the specified calls.
          The *note await_args_list: 1b11. list is checked for the
          awaits.

          If 'any_order' is false then the awaits must be sequential.
          There can be extra calls before or after the specified awaits.

          If 'any_order' is true then the awaits can be in any order,
          but they must all appear in *note await_args_list: 1b11.

               >>> mock = AsyncMock()
               >>> async def main(*args, **kwargs):
               ...     await mock(*args, **kwargs)
               ...
               >>> calls = [call("foo"), call("bar")]
               >>> mock.assert_has_awaits(calls)
               Traceback (most recent call last):
               ...
               AssertionError: Awaits not found.
               Expected: [call('foo'), call('bar')]
               Actual: []
               >>> asyncio.run(main('foo'))
               >>> asyncio.run(main('bar'))
               >>> mock.assert_has_awaits(calls)

      -- Method: assert_not_awaited ()

          Assert that the mock was never awaited.

               >>> mock = AsyncMock()
               >>> mock.assert_not_awaited()

      -- Method: reset_mock (*args, **kwargs)

          See *note Mock.reset_mock(): d21.  Also sets *note
          await_count: 431d. to 0, *note await_args: 431e. to None, and
          clears the *note await_args_list: 1b11.

      -- Attribute: await_count

          An integer keeping track of how many times the mock object has
          been awaited.

               >>> mock = AsyncMock()
               >>> async def main():
               ...     await mock()
               ...
               >>> asyncio.run(main())
               >>> mock.await_count
               1
               >>> asyncio.run(main())
               >>> mock.await_count
               2

      -- Attribute: await_args

          This is either ‘None’ (if the mock hasn’t been awaited), or
          the arguments that the mock was last awaited with.  Functions
          the same as *note Mock.call_args: 1b12.

               >>> mock = AsyncMock()
               >>> async def main(*args):
               ...     await mock(*args)
               ...
               >>> mock.await_args
               >>> asyncio.run(main('foo'))
               >>> mock.await_args
               call('foo')
               >>> asyncio.run(main('bar'))
               >>> mock.await_args
               call('bar')

      -- Attribute: await_args_list

          This is a list of all the awaits made to the mock object in
          sequence (so the length of the list is the number of times it
          has been awaited).  Before any awaits have been made it is an
          empty list.

               >>> mock = AsyncMock()
               >>> async def main(*args):
               ...     await mock(*args)
               ...
               >>> mock.await_args_list
               []
               >>> asyncio.run(main('foo'))
               >>> mock.await_args_list
               [call('foo')]
               >>> asyncio.run(main('bar'))
               >>> mock.await_args_list
               [call('foo'), call('bar')]

 -- Class: unittest.mock.ThreadingMock (spec=None, side_effect=None,
          return_value=DEFAULT, wraps=None, name=None, spec_set=None,
          unsafe=False, *, timeout=UNSET, **kwargs)

     A version of *note MagicMock: ec3. for multithreading tests.  The
     ‘ThreadingMock’ object provides extra methods to wait for a call to
     be invoked, rather than assert on it immediately.

     The default timeout is specified by the ‘timeout’ argument, or if
     unset by the *note ThreadingMock.DEFAULT_TIMEOUT: 4320. attribute,
     which defaults to blocking (‘None’).

     You can configure the global default timeout by setting *note
     ThreadingMock.DEFAULT_TIMEOUT: 4320.

      -- Method: wait_until_called (*, timeout=UNSET)

          Waits until the mock is called.

          If a timeout was passed at the creation of the mock or if a
          timeout argument is passed to this function, the function
          raises an *note AssertionError: 6ac. if the call is not
          performed in time.

               >>> mock = ThreadingMock()
               >>> thread = threading.Thread(target=mock)
               >>> thread.start()
               >>> mock.wait_until_called(timeout=1)
               >>> thread.join()

      -- Method: wait_until_any_call_with (*args, **kwargs)

          Waits until the mock is called with the specified arguments.

          If a timeout was passed at the creation of the mock the
          function raises an *note AssertionError: 6ac. if the call is
          not performed in time.

               >>> mock = ThreadingMock()
               >>> thread = threading.Thread(target=mock, args=("arg1", "arg2",), kwargs={"arg": "thing"})
               >>> thread.start()
               >>> mock.wait_until_any_call_with("arg1", "arg2", arg="thing")
               >>> thread.join()

      -- Attribute: DEFAULT_TIMEOUT

          Global default timeout in seconds to create instances of
          ‘ThreadingMock’.

     Added in version 3.13.

* Menu:

* Calling::
* Deleting Attributes::
* Mock names and the name attribute::
* Attaching Mocks as Attributes::

   ---------- Footnotes ----------

   (1) The only exceptions are magic methods and attributes (those that
have leading and trailing double underscores).  Mock doesn’t create
these but instead raises an *note AttributeError: 34e.  This is because
the interpreter will often implicitly request these methods, and gets
'very' confused to get a new Mock object when it expects a magic method.
If you need magic method support see *note magic methods: 4300.


File: python.info,  Node: Calling,  Next: Deleting Attributes,  Up: The Mock Class

5.26.6.3 Calling
................

Mock objects are callable.  The call will return the value set as the
*note return_value: 4306. attribute.  The default return value is a new
Mock object; it is created the first time the return value is accessed
(either explicitly or by calling the Mock) - but it is stored and the
same one returned each time.

Calls made to the object will be recorded in the attributes like *note
call_args: 1b12. and *note call_args_list: 4311.

If *note side_effect: 42fe. is set then it will be called after the call
has been recorded, so if ‘side_effect’ raises an exception the call is
still recorded.

The simplest way to make a mock raise an exception when called is to
make *note side_effect: 42fe. an exception class or instance:

     >>> m = MagicMock(side_effect=IndexError)
     >>> m(1, 2, 3)
     Traceback (most recent call last):
       ...
     IndexError
     >>> m.mock_calls
     [call(1, 2, 3)]
     >>> m.side_effect = KeyError('Bang!')
     >>> m('two', 'three', 'four')
     Traceback (most recent call last):
       ...
     KeyError: 'Bang!'
     >>> m.mock_calls
     [call(1, 2, 3), call('two', 'three', 'four')]

If *note side_effect: 42fe. is a function then whatever that function
returns is what calls to the mock return.  The ‘side_effect’ function is
called with the same arguments as the mock.  This allows you to vary the
return value of the call dynamically, based on the input:

     >>> def side_effect(value):
     ...     return value + 1
     ...
     >>> m = MagicMock(side_effect=side_effect)
     >>> m(1)
     2
     >>> m(2)
     3
     >>> m.mock_calls
     [call(1), call(2)]

If you want the mock to still return the default return value (a new
mock), or any set return value, then there are two ways of doing this.
Either return *note return_value: 4306. from inside *note side_effect:
42fe, or return *note DEFAULT: 4305.:

     >>> m = MagicMock()
     >>> def side_effect(*args, **kwargs):
     ...     return m.return_value
     ...
     >>> m.side_effect = side_effect
     >>> m.return_value = 3
     >>> m()
     3
     >>> def side_effect(*args, **kwargs):
     ...     return DEFAULT
     ...
     >>> m.side_effect = side_effect
     >>> m()
     3

To remove a *note side_effect: 42fe, and return to the default
behaviour, set the ‘side_effect’ to ‘None’:

     >>> m = MagicMock(return_value=6)
     >>> def side_effect(*args, **kwargs):
     ...     return 3
     ...
     >>> m.side_effect = side_effect
     >>> m()
     3
     >>> m.side_effect = None
     >>> m()
     6

The *note side_effect: 42fe. can also be any iterable object.  Repeated
calls to the mock will return values from the iterable (until the
iterable is exhausted and a *note StopIteration: c1b. is raised):

     >>> m = MagicMock(side_effect=[1, 2, 3])
     >>> m()
     1
     >>> m()
     2
     >>> m()
     3
     >>> m()
     Traceback (most recent call last):
       ...
     StopIteration

If any members of the iterable are exceptions they will be raised
instead of returned:

     >>> iterable = (33, ValueError, 66)
     >>> m = MagicMock(side_effect=iterable)
     >>> m()
     33
     >>> m()
     Traceback (most recent call last):
      ...
     ValueError
     >>> m()
     66


File: python.info,  Node: Deleting Attributes,  Next: Mock names and the name attribute,  Prev: Calling,  Up: The Mock Class

5.26.6.4 Deleting Attributes
............................

Mock objects create attributes on demand.  This allows them to pretend
to be objects of any type.

You may want a mock object to return ‘False’ to a *note hasattr(): 4d5.
call, or raise an *note AttributeError: 34e. when an attribute is
fetched.  You can do this by providing an object as a ‘spec’ for a mock,
but that isn’t always convenient.

You “block” attributes by deleting them.  Once deleted, accessing an
attribute will raise an *note AttributeError: 34e.

     >>> mock = MagicMock()
     >>> hasattr(mock, 'm')
     True
     >>> del mock.m
     >>> hasattr(mock, 'm')
     False
     >>> del mock.f
     >>> mock.f
     Traceback (most recent call last):
         ...
     AttributeError: f


File: python.info,  Node: Mock names and the name attribute,  Next: Attaching Mocks as Attributes,  Prev: Deleting Attributes,  Up: The Mock Class

5.26.6.5 Mock names and the name attribute
..........................................

Since “name” is an argument to the *note Mock: a58. constructor, if you
want your mock object to have a “name” attribute you can’t just pass it
in at creation time.  There are two alternatives.  One option is to use
*note configure_mock(): 4307.:

     >>> mock = MagicMock()
     >>> mock.configure_mock(name='my_name')
     >>> mock.name
     'my_name'

A simpler option is to simply set the “name” attribute after mock
creation:

     >>> mock = MagicMock()
     >>> mock.name = "foo"


File: python.info,  Node: Attaching Mocks as Attributes,  Prev: Mock names and the name attribute,  Up: The Mock Class

5.26.6.6 Attaching Mocks as Attributes
......................................

When you attach a mock as an attribute of another mock (or as the return
value) it becomes a “child” of that mock.  Calls to the child are
recorded in the *note method_calls: 430c. and *note mock_calls: 430a.
attributes of the parent.  This is useful for configuring child mocks
and then attaching them to the parent, or for attaching mocks to a
parent that records all calls to the children and allows you to make
assertions about the order of calls between mocks:

     >>> parent = MagicMock()
     >>> child1 = MagicMock(return_value=None)
     >>> child2 = MagicMock(return_value=None)
     >>> parent.child1 = child1
     >>> parent.child2 = child2
     >>> child1(1)
     >>> child2(2)
     >>> parent.mock_calls
     [call.child1(1), call.child2(2)]

The exception to this is if the mock has a name.  This allows you to
prevent the “parenting” if for some reason you don’t want it to happen.

     >>> mock = MagicMock()
     >>> not_a_child = MagicMock(name='not-a-child')
     >>> mock.attribute = not_a_child
     >>> mock.attribute()
     <MagicMock name='not-a-child()' id='...'>
     >>> mock.mock_calls
     []

Mocks created for you by *note patch(): ec6. are automatically given
names.  To attach mocks that have names to a parent you use the *note
attach_mock(): 1718. method:

     >>> thing1 = object()
     >>> thing2 = object()
     >>> parent = MagicMock()
     >>> with patch('__main__.thing1', return_value=None) as child1:
     ...     with patch('__main__.thing2', return_value=None) as child2:
     ...         parent.attach_mock(child1, 'child1')
     ...         parent.attach_mock(child2, 'child2')
     ...         child1('one')
     ...         child2('two')
     ...
     >>> parent.mock_calls
     [call.child1('one'), call.child2('two')]


File: python.info,  Node: The patchers,  Next: MagicMock and magic method support,  Prev: The Mock Class,  Up: unittest mock — mock object library

5.26.6.7 The patchers
.....................

The patch decorators are used for patching objects only within the scope
of the function they decorate.  They automatically handle the unpatching
for you, even if exceptions are raised.  All of these functions can also
be used in with statements or as class decorators.

* Menu:

* patch::
* patch.object: patch object.
* patch.dict: patch dict.
* patch.multiple: patch multiple.
* patch methods; start and stop: patch methods start and stop.
* patch builtins::
* TEST_PREFIX::
* Nesting Patch Decorators::
* Where to patch::
* Patching Descriptors and Proxy Objects::


File: python.info,  Node: patch,  Next: patch object,  Up: The patchers

5.26.6.8 patch
..............

     Note: The key is to do the patching in the right namespace.  See
     the section *note where to patch: 432a.

 -- Function: unittest.mock.patch (target, new=DEFAULT, spec=None,
          create=False, spec_set=None, autospec=None, new_callable=None,
          **kwargs)

     ‘patch()’ acts as a function decorator, class decorator or a
     context manager.  Inside the body of the function or with
     statement, the 'target' is patched with a 'new' object.  When the
     function/with statement exits the patch is undone.

     If 'new' is omitted, then the target is replaced with an *note
     AsyncMock: a57. if the patched object is an async function or a
     *note MagicMock: ec3. otherwise.  If ‘patch()’ is used as a
     decorator and 'new' is omitted, the created mock is passed in as an
     extra argument to the decorated function.  If ‘patch()’ is used as
     a context manager the created mock is returned by the context
     manager.

     'target' should be a string in the form
     ‘'package.module.ClassName'’.  The 'target' is imported and the
     specified object replaced with the 'new' object, so the 'target'
     must be importable from the environment you are calling ‘patch()’
     from.  The target is imported when the decorated function is
     executed, not at decoration time.

     The 'spec' and 'spec_set' keyword arguments are passed to the *note
     MagicMock: ec3. if patch is creating one for you.

     In addition you can pass ‘spec=True’ or ‘spec_set=True’, which
     causes patch to pass in the object being mocked as the
     spec/spec_set object.

     'new_callable' allows you to specify a different class, or callable
     object, that will be called to create the 'new' object.  By default
     *note AsyncMock: a57. is used for async functions and *note
     MagicMock: ec3. for the rest.

     A more powerful form of 'spec' is 'autospec'.  If you set
     ‘autospec=True’ then the mock will be created with a spec from the
     object being replaced.  All attributes of the mock will also have
     the spec of the corresponding attribute of the object being
     replaced.  Methods and functions being mocked will have their
     arguments checked and will raise a *note TypeError: 2c3. if they
     are called with the wrong signature.  For mocks replacing a class,
     their return value (the ‘instance’) will have the same spec as the
     class.  See the *note create_autospec(): 1712. function and *note
     Autospeccing: 4301.

     Instead of ‘autospec=True’ you can pass ‘autospec=some_object’ to
     use an arbitrary object as the spec instead of the one being
     replaced.

     By default ‘patch()’ will fail to replace attributes that don’t
     exist.  If you pass in ‘create=True’, and the attribute doesn’t
     exist, patch will create the attribute for you when the patched
     function is called, and delete it again after the patched function
     has exited.  This is useful for writing tests against attributes
     that your production code creates at runtime.  It is off by default
     because it can be dangerous.  With it switched on you can write
     passing tests against APIs that don’t actually exist!

          Note: 
          Changed in version 3.5: If you are patching builtins in a
          module then you don’t need to pass ‘create=True’, it will be
          added by default.

     Patch can be used as a *note TestCase: 451. class decorator.  It
     works by decorating each test method in the class.  This reduces
     the boilerplate code when your test methods share a common
     patchings set.  ‘patch()’ finds tests by looking for method names
     that start with ‘patch.TEST_PREFIX’.  By default this is ‘'test'’,
     which matches the way *note unittest: 106. finds tests.  You can
     specify an alternative prefix by setting ‘patch.TEST_PREFIX’.

     Patch can be used as a context manager, with the with statement.
     Here the patching applies to the indented block after the with
     statement.  If you use “as” then the patched object will be bound
     to the name after the “as”; very useful if ‘patch()’ is creating a
     mock object for you.

     ‘patch()’ takes arbitrary keyword arguments.  These will be passed
     to *note AsyncMock: a57. if the patched object is asynchronous, to
     *note MagicMock: ec3. otherwise or to 'new_callable' if specified.

     ‘patch.dict(...)’, ‘patch.multiple(...)’ and ‘patch.object(...)’
     are available for alternate use-cases.

*note patch(): ec6. as function decorator, creating the mock for you and
passing it into the decorated function:

     >>> @patch('__main__.SomeClass')
     ... def function(normal_argument, mock_class):
     ...     print(mock_class is SomeClass)
     ...
     >>> function(None)
     True

Patching a class replaces the class with a *note MagicMock: ec3.
'instance'.  If the class is instantiated in the code under test then it
will be the *note return_value: 4306. of the mock that will be used.

If the class is instantiated multiple times you could use *note
side_effect: 42fe. to return a new mock each time.  Alternatively you
can set the 'return_value' to be anything you want.

To configure return values on methods of 'instances' on the patched
class you must do this on the *note return_value: 4306.  For example:

     >>> class Class:
     ...     def method(self):
     ...         pass
     ...
     >>> with patch('__main__.Class') as MockClass:
     ...     instance = MockClass.return_value
     ...     instance.method.return_value = 'foo'
     ...     assert Class() is instance
     ...     assert Class().method() == 'foo'
     ...

If you use 'spec' or 'spec_set' and *note patch(): ec6. is replacing a
'class', then the return value of the created mock will have the same
spec.

     >>> Original = Class
     >>> patcher = patch('__main__.Class', spec=True)
     >>> MockClass = patcher.start()
     >>> instance = MockClass()
     >>> assert isinstance(instance, Original)
     >>> patcher.stop()

The 'new_callable' argument is useful where you want to use an
alternative class to the default *note MagicMock: ec3. for the created
mock.  For example, if you wanted a *note NonCallableMock: 4303. to be
used:

     >>> thing = object()
     >>> with patch('__main__.thing', new_callable=NonCallableMock) as mock_thing:
     ...     assert thing is mock_thing
     ...     thing()
     ...
     Traceback (most recent call last):
       ...
     TypeError: 'NonCallableMock' object is not callable

Another use case might be to replace an object with an *note
io.StringIO: f5e. instance:

     >>> from io import StringIO
     >>> def foo():
     ...     print('Something')
     ...
     >>> @patch('sys.stdout', new_callable=StringIO)
     ... def test(mock_stdout):
     ...     foo()
     ...     assert mock_stdout.getvalue() == 'Something\n'
     ...
     >>> test()

When *note patch(): ec6. is creating a mock for you, it is common that
the first thing you need to do is to configure the mock.  Some of that
configuration can be done in the call to patch.  Any arbitrary keywords
you pass into the call will be used to set attributes on the created
mock:

     >>> patcher = patch('__main__.thing', first='one', second='two')
     >>> mock_thing = patcher.start()
     >>> mock_thing.first
     'one'
     >>> mock_thing.second
     'two'

As well as attributes on the created mock attributes, like the *note
return_value: 4306. and *note side_effect: 42fe, of child mocks can also
be configured.  These aren’t syntactically valid to pass in directly as
keyword arguments, but a dictionary with these as keys can still be
expanded into a *note patch(): ec6. call using ‘**’:

     >>> config = {'method.return_value': 3, 'other.side_effect': KeyError}
     >>> patcher = patch('__main__.thing', **config)
     >>> mock_thing = patcher.start()
     >>> mock_thing.method()
     3
     >>> mock_thing.other()
     Traceback (most recent call last):
       ...
     KeyError

By default, attempting to patch a function in a module (or a method or
an attribute in a class) that does not exist will fail with *note
AttributeError: 34e.:

     >>> @patch('sys.non_existing_attribute', 42)
     ... def test():
     ...     assert sys.non_existing_attribute == 42
     ...
     >>> test()
     Traceback (most recent call last):
       ...
     AttributeError: <module 'sys' (built-in)> does not have the attribute 'non_existing_attribute'

but adding ‘create=True’ in the call to *note patch(): ec6. will make
the previous example work as expected:

     >>> @patch('sys.non_existing_attribute', 42, create=True)
     ... def test(mock_stdout):
     ...     assert sys.non_existing_attribute == 42
     ...
     >>> test()

Changed in version 3.8: *note patch(): ec6. now returns an *note
AsyncMock: a57. if the target is an async function.


File: python.info,  Node: patch object,  Next: patch dict,  Prev: patch,  Up: The patchers

5.26.6.9 patch.object
.....................

 -- Function: patch.object (target, attribute, new=DEFAULT, spec=None,
          create=False, spec_set=None, autospec=None, new_callable=None,
          **kwargs)

     patch the named member ('attribute') on an object ('target') with a
     mock object.

     ‘patch.object()’ can be used as a decorator, class decorator or a
     context manager.  Arguments 'new', 'spec', 'create', 'spec_set',
     'autospec' and 'new_callable' have the same meaning as for *note
     patch(): ec6.  Like ‘patch()’, ‘patch.object()’ takes arbitrary
     keyword arguments for configuring the mock object it creates.

     When used as a class decorator ‘patch.object()’ honours
     ‘patch.TEST_PREFIX’ for choosing which methods to wrap.

You can either call *note patch.object(): 169e. with three arguments or
two arguments.  The three argument form takes the object to be patched,
the attribute name and the object to replace the attribute with.

When calling with the two argument form you omit the replacement object,
and a mock is created for you and passed in as an extra argument to the
decorated function:

     >>> @patch.object(SomeClass, 'class_method')
     ... def test(mock_method):
     ...     SomeClass.class_method(3)
     ...     mock_method.assert_called_with(3)
     ...
     >>> test()

'spec', 'create' and the other arguments to *note patch.object(): 169e.
have the same meaning as they do for *note patch(): ec6.


File: python.info,  Node: patch dict,  Next: patch multiple,  Prev: patch object,  Up: The patchers

5.26.6.10 patch.dict
....................

 -- Function: patch.dict (in_dict, values=(), clear=False, **kwargs)

     Patch a dictionary, or dictionary like object, and restore the
     dictionary to its original state after the test.

     'in_dict' can be a dictionary or a mapping like container.  If it
     is a mapping then it must at least support getting, setting and
     deleting items plus iterating over keys.

     'in_dict' can also be a string specifying the name of the
     dictionary, which will then be fetched by importing it.

     'values' can be a dictionary of values to set in the dictionary.
     'values' can also be an iterable of ‘(key, value)’ pairs.

     If 'clear' is true then the dictionary will be cleared before the
     new values are set.

     ‘patch.dict()’ can also be called with arbitrary keyword arguments
     to set values in the dictionary.

     Changed in version 3.8: ‘patch.dict()’ now returns the patched
     dictionary when used as a context manager.

*note patch.dict(): 1b83. can be used as a context manager, decorator or
class decorator:

     >>> foo = {}
     >>> @patch.dict(foo, {'newkey': 'newvalue'})
     ... def test():
     ...     assert foo == {'newkey': 'newvalue'}
     ...
     >>> test()
     >>> assert foo == {}

When used as a class decorator *note patch.dict(): 1b83. honours
‘patch.TEST_PREFIX’ (default to ‘'test'’) for choosing which methods to
wrap:

     >>> import os
     >>> import unittest
     >>> from unittest.mock import patch
     >>> @patch.dict('os.environ', {'newkey': 'newvalue'})
     ... class TestSample(unittest.TestCase):
     ...     def test_sample(self):
     ...         self.assertEqual(os.environ['newkey'], 'newvalue')

If you want to use a different prefix for your test, you can inform the
patchers of the different prefix by setting ‘patch.TEST_PREFIX’.  For
more details about how to change the value of see *note TEST_PREFIX:
432d.

*note patch.dict(): 1b83. can be used to add members to a dictionary, or
simply let a test change a dictionary, and ensure the dictionary is
restored when the test ends.

     >>> foo = {}
     >>> with patch.dict(foo, {'newkey': 'newvalue'}) as patched_foo:
     ...     assert foo == {'newkey': 'newvalue'}
     ...     assert patched_foo == {'newkey': 'newvalue'}
     ...     # You can add, update or delete keys of foo (or patched_foo, it's the same dict)
     ...     patched_foo['spam'] = 'eggs'
     ...
     >>> assert foo == {}
     >>> assert patched_foo == {}

     >>> import os
     >>> with patch.dict('os.environ', {'newkey': 'newvalue'}):
     ...     print(os.environ['newkey'])
     ...
     newvalue
     >>> assert 'newkey' not in os.environ

Keywords can be used in the *note patch.dict(): 1b83. call to set values
in the dictionary:

     >>> mymodule = MagicMock()
     >>> mymodule.function.return_value = 'fish'
     >>> with patch.dict('sys.modules', mymodule=mymodule):
     ...     import mymodule
     ...     mymodule.function('some', 'args')
     ...
     'fish'

*note patch.dict(): 1b83. can be used with dictionary like objects that
aren’t actually dictionaries.  At the very minimum they must support
item getting, setting, deleting and either iteration or membership test.
This corresponds to the magic methods *note __getitem__(): 283, *note
__setitem__(): 1313, *note __delitem__(): 1314. and either *note
__iter__(): 1e62. or *note __contains__(): 1406.

     >>> class Container:
     ...     def __init__(self):
     ...         self.values = {}
     ...     def __getitem__(self, name):
     ...         return self.values[name]
     ...     def __setitem__(self, name, value):
     ...         self.values[name] = value
     ...     def __delitem__(self, name):
     ...         del self.values[name]
     ...     def __iter__(self):
     ...         return iter(self.values)
     ...
     >>> thing = Container()
     >>> thing['one'] = 1
     >>> with patch.dict(thing, one=2, two=3):
     ...     assert thing['one'] == 2
     ...     assert thing['two'] == 3
     ...
     >>> assert thing['one'] == 1
     >>> assert list(thing) == ['one']


File: python.info,  Node: patch multiple,  Next: patch methods start and stop,  Prev: patch dict,  Up: The patchers

5.26.6.11 patch.multiple
........................

 -- Function: patch.multiple (target, spec=None, create=False,
          spec_set=None, autospec=None, new_callable=None, **kwargs)

     Perform multiple patches in a single call.  It takes the object to
     be patched (either as an object or a string to fetch the object by
     importing) and keyword arguments for the patches:

          with patch.multiple(settings, FIRST_PATCH='one', SECOND_PATCH='two'):
              ...

     Use *note DEFAULT: 4305. as the value if you want
     ‘patch.multiple()’ to create mocks for you.  In this case the
     created mocks are passed into a decorated function by keyword, and
     a dictionary is returned when ‘patch.multiple()’ is used as a
     context manager.

     ‘patch.multiple()’ can be used as a decorator, class decorator or a
     context manager.  The arguments 'spec', 'spec_set', 'create',
     'autospec' and 'new_callable' have the same meaning as for *note
     patch(): ec6.  These arguments will be applied to 'all' patches
     done by ‘patch.multiple()’.

     When used as a class decorator ‘patch.multiple()’ honours
     ‘patch.TEST_PREFIX’ for choosing which methods to wrap.

If you want *note patch.multiple(): 432f. to create mocks for you, then
you can use *note DEFAULT: 4305. as the value.  If you use
‘patch.multiple()’ as a decorator then the created mocks are passed into
the decorated function by keyword.

     >>> thing = object()
     >>> other = object()

     >>> @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
     ... def test_function(thing, other):
     ...     assert isinstance(thing, MagicMock)
     ...     assert isinstance(other, MagicMock)
     ...
     >>> test_function()

*note patch.multiple(): 432f. can be nested with other ‘patch’
decorators, but put arguments passed by keyword 'after' any of the
standard arguments created by *note patch(): ec6.:

     >>> @patch('sys.exit')
     ... @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
     ... def test_function(mock_exit, other, thing):
     ...     assert 'other' in repr(other)
     ...     assert 'thing' in repr(thing)
     ...     assert 'exit' in repr(mock_exit)
     ...
     >>> test_function()

If *note patch.multiple(): 432f. is used as a context manager, the value
returned by the context manager is a dictionary where created mocks are
keyed by name:

     >>> with patch.multiple('__main__', thing=DEFAULT, other=DEFAULT) as values:
     ...     assert 'other' in repr(values['other'])
     ...     assert 'thing' in repr(values['thing'])
     ...     assert values['thing'] is thing
     ...     assert values['other'] is other
     ...


File: python.info,  Node: patch methods start and stop,  Next: patch builtins,  Prev: patch multiple,  Up: The patchers

5.26.6.12 patch methods: start and stop
.......................................

All the patchers have ‘start()’ and ‘stop()’ methods.  These make it
simpler to do patching in ‘setUp’ methods or where you want to do
multiple patches without nesting decorators or with statements.

To use them call *note patch(): ec6, *note patch.object(): 169e. or
*note patch.dict(): 1b83. as normal and keep a reference to the returned
‘patcher’ object.  You can then call ‘start()’ to put the patch in place
and ‘stop()’ to undo it.

If you are using *note patch(): ec6. to create a mock for you then it
will be returned by the call to ‘patcher.start’.

     >>> patcher = patch('package.module.ClassName')
     >>> from package import module
     >>> original = module.ClassName
     >>> new_mock = patcher.start()
     >>> assert module.ClassName is not original
     >>> assert module.ClassName is new_mock
     >>> patcher.stop()
     >>> assert module.ClassName is original
     >>> assert module.ClassName is not new_mock

A typical use case for this might be for doing multiple patches in the
‘setUp’ method of a *note TestCase: 451.:

     >>> class MyTest(unittest.TestCase):
     ...     def setUp(self):
     ...         self.patcher1 = patch('package.module.Class1')
     ...         self.patcher2 = patch('package.module.Class2')
     ...         self.MockClass1 = self.patcher1.start()
     ...         self.MockClass2 = self.patcher2.start()
     ...
     ...     def tearDown(self):
     ...         self.patcher1.stop()
     ...         self.patcher2.stop()
     ...
     ...     def test_something(self):
     ...         assert package.module.Class1 is self.MockClass1
     ...         assert package.module.Class2 is self.MockClass2
     ...
     >>> MyTest('test_something').run()

     Caution: If you use this technique you must ensure that the
     patching is “undone” by calling ‘stop’.  This can be fiddlier than
     you might think, because if an exception is raised in the ‘setUp’
     then ‘tearDown’ is not called.  *note
     unittest.TestCase.addCleanup(): a90. makes this easier:

          >>> class MyTest(unittest.TestCase):
          ...     def setUp(self):
          ...         patcher = patch('package.module.Class')
          ...         self.MockClass = patcher.start()
          ...         self.addCleanup(patcher.stop)
          ...
          ...     def test_something(self):
          ...         assert package.module.Class is self.MockClass
          ...

     As an added bonus you no longer need to keep a reference to the
     ‘patcher’ object.

It is also possible to stop all patches which have been started by using
*note patch.stopall(): 4332.

 -- Function: patch.stopall ()

     Stop all active patches.  Only stops patches started with ‘start’.


File: python.info,  Node: patch builtins,  Next: TEST_PREFIX,  Prev: patch methods start and stop,  Up: The patchers

5.26.6.13 patch builtins
........................

You can patch any builtins within a module.  The following example
patches builtin *note ord(): 209f.:

     >>> @patch('__main__.ord')
     ... def test(mock_ord):
     ...     mock_ord.return_value = 101
     ...     print(ord('c'))
     ...
     >>> test()
     101


File: python.info,  Node: TEST_PREFIX,  Next: Nesting Patch Decorators,  Prev: patch builtins,  Up: The patchers

5.26.6.14 TEST_PREFIX
.....................

All of the patchers can be used as class decorators.  When used in this
way they wrap every test method on the class.  The patchers recognise
methods that start with ‘'test'’ as being test methods.  This is the
same way that the *note unittest.TestLoader: 28e. finds test methods by
default.

It is possible that you want to use a different prefix for your tests.
You can inform the patchers of the different prefix by setting
‘patch.TEST_PREFIX’:

     >>> patch.TEST_PREFIX = 'foo'
     >>> value = 3
     >>>
     >>> @patch('__main__.value', 'not three')
     ... class Thing:
     ...     def foo_one(self):
     ...         print(value)
     ...     def foo_two(self):
     ...         print(value)
     ...
     >>>
     >>> Thing().foo_one()
     not three
     >>> Thing().foo_two()
     not three
     >>> value
     3


File: python.info,  Node: Nesting Patch Decorators,  Next: Where to patch,  Prev: TEST_PREFIX,  Up: The patchers

5.26.6.15 Nesting Patch Decorators
..................................

If you want to perform multiple patches then you can simply stack up the
decorators.

You can stack up multiple patch decorators using this pattern:

     >>> @patch.object(SomeClass, 'class_method')
     ... @patch.object(SomeClass, 'static_method')
     ... def test(mock1, mock2):
     ...     assert SomeClass.static_method is mock1
     ...     assert SomeClass.class_method is mock2
     ...     SomeClass.static_method('foo')
     ...     SomeClass.class_method('bar')
     ...     return mock1, mock2
     ...
     >>> mock1, mock2 = test()
     >>> mock1.assert_called_once_with('foo')
     >>> mock2.assert_called_once_with('bar')

Note that the decorators are applied from the bottom upwards.  This is
the standard way that Python applies decorators.  The order of the
created mocks passed into your test function matches this order.


File: python.info,  Node: Where to patch,  Next: Patching Descriptors and Proxy Objects,  Prev: Nesting Patch Decorators,  Up: The patchers

5.26.6.16 Where to patch
........................

*note patch(): ec6. works by (temporarily) changing the object that a
'name' points to with another one.  There can be many names pointing to
any individual object, so for patching to work you must ensure that you
patch the name used by the system under test.

The basic principle is that you patch where an object is 'looked up',
which is not necessarily the same place as where it is defined.  A
couple of examples will help to clarify this.

Imagine we have a project that we want to test with the following
structure:

     a.py
         -> Defines SomeClass

     b.py
         -> from a import SomeClass
         -> some_function instantiates SomeClass

Now we want to test ‘some_function’ but we want to mock out ‘SomeClass’
using *note patch(): ec6.  The problem is that when we import module b,
which we will have to do when it imports ‘SomeClass’ from module a.  If
we use ‘patch()’ to mock out ‘a.SomeClass’ then it will have no effect
on our test; module b already has a reference to the 'real' ‘SomeClass’
and it looks like our patching had no effect.

The key is to patch out ‘SomeClass’ where it is used (or where it is
looked up).  In this case ‘some_function’ will actually look up
‘SomeClass’ in module b, where we have imported it.  The patching should
look like:

     @patch('b.SomeClass')

However, consider the alternative scenario where instead of ‘from a
import SomeClass’ module b does ‘import a’ and ‘some_function’ uses
‘a.SomeClass’.  Both of these import forms are common.  In this case the
class we want to patch is being looked up in the module and so we have
to patch ‘a.SomeClass’ instead:

     @patch('a.SomeClass')


File: python.info,  Node: Patching Descriptors and Proxy Objects,  Prev: Where to patch,  Up: The patchers

5.26.6.17 Patching Descriptors and Proxy Objects
................................................

Both *note patch: 4329. and *note patch.object: 432b. correctly patch
and restore descriptors: class methods, static methods and properties.
You should patch these on the 'class' rather than an instance.  They
also work with 'some' objects that proxy attribute access, like the
django settings object(1).

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20200603181648/http://www.voidspace.org.uk/python/weblog/arch_d7_2010_12_04.shtml#e1198


File: python.info,  Node: MagicMock and magic method support,  Next: Helpers,  Prev: The patchers,  Up: unittest mock — mock object library

5.26.6.18 MagicMock and magic method support
............................................

* Menu:

* Mocking Magic Methods::
* Magic Mock::


File: python.info,  Node: Mocking Magic Methods,  Next: Magic Mock,  Up: MagicMock and magic method support

5.26.6.19 Mocking Magic Methods
...............................

*note Mock: a58. supports mocking the Python protocol methods, also
known as *note “magic methods”: 433a.  This allows mock objects to
replace containers or other objects that implement Python protocols.

Because magic methods are looked up differently from normal methods (1),
this support has been specially implemented.  This means that only
specific magic methods are supported.  The supported list includes
'almost' all of them.  If there are any missing that you need please let
us know.

You mock magic methods by setting the method you are interested in to a
function or a mock instance.  If you are using a function then it 'must'
take ‘self’ as the first argument (2).

     >>> def __str__(self):
     ...     return 'fooble'
     ...
     >>> mock = Mock()
     >>> mock.__str__ = __str__
     >>> str(mock)
     'fooble'

     >>> mock = Mock()
     >>> mock.__str__ = Mock()
     >>> mock.__str__.return_value = 'fooble'
     >>> str(mock)
     'fooble'

     >>> mock = Mock()
     >>> mock.__iter__ = Mock(return_value=iter([]))
     >>> list(mock)
     []

One use case for this is for mocking objects used as context managers in
a *note with: 5d5. statement:

     >>> mock = Mock()
     >>> mock.__enter__ = Mock(return_value='foo')
     >>> mock.__exit__ = Mock(return_value=False)
     >>> with mock as m:
     ...     assert m == 'foo'
     ...
     >>> mock.__enter__.assert_called_with()
     >>> mock.__exit__.assert_called_with(None, None, None)

Calls to magic methods do not appear in *note method_calls: 430c, but
they are recorded in *note mock_calls: 430a.

     Note: If you use the 'spec' keyword argument to create a mock then
     attempting to set a magic method that isn’t in the spec will raise
     an *note AttributeError: 34e.

The full list of supported magic methods is:

   * ‘__hash__’, ‘__sizeof__’, ‘__repr__’ and ‘__str__’

   * ‘__dir__’, ‘__format__’ and ‘__subclasses__’

   * ‘__round__’, ‘__floor__’, ‘__trunc__’ and ‘__ceil__’

   * Comparisons: ‘__lt__’, ‘__gt__’, ‘__le__’, ‘__ge__’, ‘__eq__’ and
     ‘__ne__’

   * Container methods: ‘__getitem__’, ‘__setitem__’, ‘__delitem__’,
     ‘__contains__’, ‘__len__’, ‘__iter__’, ‘__reversed__’ and
     ‘__missing__’

   * Context manager: ‘__enter__’, ‘__exit__’, ‘__aenter__’ and
     ‘__aexit__’

   * Unary numeric methods: ‘__neg__’, ‘__pos__’ and ‘__invert__’

   * The numeric methods (including right hand and in-place variants):
     ‘__add__’, ‘__sub__’, ‘__mul__’, ‘__matmul__’, ‘__truediv__’,
     ‘__floordiv__’, ‘__mod__’, ‘__divmod__’, ‘__lshift__’,
     ‘__rshift__’, ‘__and__’, ‘__xor__’, ‘__or__’, and ‘__pow__’

   * Numeric conversion methods: ‘__complex__’, ‘__int__’, ‘__float__’
     and ‘__index__’

   * Descriptor methods: ‘__get__’, ‘__set__’ and ‘__delete__’

   * Pickling: ‘__reduce__’, ‘__reduce_ex__’, ‘__getinitargs__’,
     ‘__getnewargs__’, ‘__getstate__’ and ‘__setstate__’

   * File system path representation: ‘__fspath__’

   * Asynchronous iteration methods: ‘__aiter__’ and ‘__anext__’

Changed in version 3.8: Added support for *note
os.PathLike.__fspath__(): c73.

Changed in version 3.8: Added support for ‘__aenter__’, ‘__aexit__’,
‘__aiter__’ and ‘__anext__’.

The following methods exist but are 'not' supported as they are either
in use by mock, can’t be set dynamically, or can cause problems:

   * ‘__getattr__’, ‘__setattr__’, ‘__init__’ and ‘__new__’

   * ‘__prepare__’, ‘__instancecheck__’, ‘__subclasscheck__’, ‘__del__’

   ---------- Footnotes ----------

   (1) Magic methods 'should' be looked up on the class rather than the
instance.  Different versions of Python are inconsistent about applying
this rule.  The supported protocol methods should work with all
supported versions of Python.

   (2) The function is basically hooked up to the class, but each ‘Mock’
instance is kept isolated from the others.


File: python.info,  Node: Magic Mock,  Prev: Mocking Magic Methods,  Up: MagicMock and magic method support

5.26.6.20 Magic Mock
....................

There are two ‘MagicMock’ variants: *note MagicMock: ec3. and *note
NonCallableMagicMock: 4304.

 -- Class: unittest.mock.MagicMock (*args, **kw)

     ‘MagicMock’ is a subclass of *note Mock: a58. with default
     implementations of most of the *note magic methods: 433a.  You can
     use ‘MagicMock’ without having to configure the magic methods
     yourself.

     The constructor parameters have the same meaning as for *note Mock:
     a58.

     If you use the 'spec' or 'spec_set' arguments then 'only' magic
     methods that exist in the spec will be created.

 -- Class: unittest.mock.NonCallableMagicMock (*args, **kw)

     A non-callable version of *note MagicMock: ec3.

     The constructor parameters have the same meaning as for *note
     MagicMock: ec3, with the exception of 'return_value' and
     'side_effect' which have no meaning on a non-callable mock.

The magic methods are setup with *note MagicMock: ec3. objects, so you
can configure them and use them in the usual way:

     >>> mock = MagicMock()
     >>> mock[3] = 'fish'
     >>> mock.__setitem__.assert_called_with(3, 'fish')
     >>> mock.__getitem__.return_value = 'result'
     >>> mock[2]
     'result'

By default many of the protocol methods are required to return objects
of a specific type.  These methods are preconfigured with a default
return value, so that they can be used without you having to do anything
if you aren’t interested in the return value.  You can still 'set' the
return value manually if you want to change the default.

Methods and their defaults:

   * ‘__lt__’: *note NotImplemented: 7d6.

   * ‘__gt__’: ‘NotImplemented’

   * ‘__le__’: ‘NotImplemented’

   * ‘__ge__’: ‘NotImplemented’

   * ‘__int__’: ‘1’

   * ‘__contains__’: ‘False’

   * ‘__len__’: ‘0’

   * ‘__iter__’: ‘iter([])’

   * ‘__exit__’: ‘False’

   * ‘__aexit__’: ‘False’

   * ‘__complex__’: ‘1j’

   * ‘__float__’: ‘1.0’

   * ‘__bool__’: ‘True’

   * ‘__index__’: ‘1’

   * ‘__hash__’: default hash for the mock

   * ‘__str__’: default str for the mock

   * ‘__sizeof__’: default sizeof for the mock

For example:

     >>> mock = MagicMock()
     >>> int(mock)
     1
     >>> len(mock)
     0
     >>> list(mock)
     []
     >>> object() in mock
     False

The two equality methods, ‘__eq__()’ and ‘__ne__()’, are special.  They
do the default equality comparison on identity, using the *note
side_effect: 42fe. attribute, unless you change their return value to
return something else:

     >>> MagicMock() == 3
     False
     >>> MagicMock() != 3
     True
     >>> mock = MagicMock()
     >>> mock.__eq__.return_value = True
     >>> mock == 3
     True

The return value of ‘MagicMock.__iter__()’ can be any iterable object
and isn’t required to be an iterator:

     >>> mock = MagicMock()
     >>> mock.__iter__.return_value = ['a', 'b', 'c']
     >>> list(mock)
     ['a', 'b', 'c']
     >>> list(mock)
     ['a', 'b', 'c']

If the return value 'is' an iterator, then iterating over it once will
consume it and subsequent iterations will result in an empty list:

     >>> mock.__iter__.return_value = iter(['a', 'b', 'c'])
     >>> list(mock)
     ['a', 'b', 'c']
     >>> list(mock)
     []

‘MagicMock’ has all of the supported magic methods configured except for
some of the obscure and obsolete ones.  You can still set these up if
you want.

Magic methods that are supported but not setup by default in ‘MagicMock’
are:

   * ‘__subclasses__’

   * ‘__dir__’

   * ‘__format__’

   * ‘__get__’, ‘__set__’ and ‘__delete__’

   * ‘__reversed__’ and ‘__missing__’

   * ‘__reduce__’, ‘__reduce_ex__’, ‘__getinitargs__’, ‘__getnewargs__’,
     ‘__getstate__’ and ‘__setstate__’

   * ‘__getformat__’


File: python.info,  Node: Helpers,  Next: Order of precedence of side_effect return_value and wraps,  Prev: MagicMock and magic method support,  Up: unittest mock — mock object library

5.26.6.21 Helpers
.................

* Menu:

* sentinel::
* DEFAULT::
* call::
* create_autospec::
* ANY::
* FILTER_DIR::
* mock_open::
* Autospeccing::
* Sealing mocks::


File: python.info,  Node: sentinel,  Next: DEFAULT,  Up: Helpers

5.26.6.22 sentinel
..................

 -- Data: unittest.mock.sentinel

     The ‘sentinel’ object provides a convenient way of providing unique
     objects for your tests.

     Attributes are created on demand when you access them by name.
     Accessing the same attribute will always return the same object.
     The objects returned have a sensible repr so that test failure
     messages are readable.

     Changed in version 3.7: The ‘sentinel’ attributes now preserve
     their identity when they are *note copied: 25. or *note pickled:
     a6.

Sometimes when testing you need to test that a specific object is passed
as an argument to another method, or returned.  It can be common to
create named sentinel objects to test this.  *note sentinel: bbe.
provides a convenient way of creating and testing the identity of
objects like this.

In this example we monkey patch ‘method’ to return
‘sentinel.some_object’:

     >>> real = ProductionClass()
     >>> real.method = Mock(name="method")
     >>> real.method.return_value = sentinel.some_object
     >>> result = real.method()
     >>> assert result is sentinel.some_object
     >>> result
     sentinel.some_object


File: python.info,  Node: DEFAULT,  Next: call,  Prev: sentinel,  Up: Helpers

5.26.6.23 DEFAULT
.................

 -- Data: unittest.mock.DEFAULT

     The ‘DEFAULT’ object is a pre-created sentinel (actually
     ‘sentinel.DEFAULT’).  It can be used by *note side_effect: 42fe.
     functions to indicate that the normal return value should be used.


File: python.info,  Node: call,  Next: create_autospec,  Prev: DEFAULT,  Up: Helpers

5.26.6.24 call
..............

 -- Function: unittest.mock.call (*args, **kwargs)

     ‘call()’ is a helper object for making simpler assertions, for
     comparing with *note call_args: 1b12, *note call_args_list: 4311,
     *note mock_calls: 430a. and *note method_calls: 430c.  ‘call()’ can
     also be used with *note assert_has_calls(): 17ba.

          >>> m = MagicMock(return_value=None)
          >>> m(1, 2, a='foo', b='bar')
          >>> m()
          >>> m.call_args_list == [call(1, 2, a='foo', b='bar'), call()]
          True

 -- Method: call.call_list ()

     For a call object that represents multiple calls, ‘call_list()’
     returns a list of all the intermediate calls as well as the final
     call.

‘call_list’ is particularly useful for making assertions on “chained
calls”.  A chained call is multiple calls on a single line of code.
This results in multiple entries in *note mock_calls: 430a. on a mock.
Manually constructing the sequence of calls can be tedious.

*note call_list(): 4340. can construct the sequence of calls from the
same chained call:

     >>> m = MagicMock()
     >>> m(1).method(arg='foo').other('bar')(2.0)
     <MagicMock name='mock().method().other()()' id='...'>
     >>> kall = call(1).method(arg='foo').other('bar')(2.0)
     >>> kall.call_list()
     [call(1),
      call().method(arg='foo'),
      call().method().other('bar'),
      call().method().other()(2.0)]
     >>> m.mock_calls == kall.call_list()
     True
A ‘call’ object is either a tuple of (positional args, keyword args) or
(name, positional args, keyword args) depending on how it was
constructed.  When you construct them yourself this isn’t particularly
interesting, but the ‘call’ objects that are in the *note
Mock.call_args: 1b12, *note Mock.call_args_list: 4311. and *note
Mock.mock_calls: 430a. attributes can be introspected to get at the
individual arguments they contain.

The ‘call’ objects in *note Mock.call_args: 1b12. and *note
Mock.call_args_list: 4311. are two-tuples of (positional args, keyword
args) whereas the ‘call’ objects in *note Mock.mock_calls: 430a, along
with ones you construct yourself, are three-tuples of (name, positional
args, keyword args).

You can use their “tupleness” to pull out the individual arguments for
more complex introspection and assertions.  The positional arguments are
a tuple (an empty tuple if there are no positional arguments) and the
keyword arguments are a dictionary:

     >>> m = MagicMock(return_value=None)
     >>> m(1, 2, 3, arg='one', arg2='two')
     >>> kall = m.call_args
     >>> kall.args
     (1, 2, 3)
     >>> kall.kwargs
     {'arg': 'one', 'arg2': 'two'}
     >>> kall.args is kall[0]
     True
     >>> kall.kwargs is kall[1]
     True

     >>> m = MagicMock()
     >>> m.foo(4, 5, 6, arg='two', arg2='three')
     <MagicMock name='mock.foo()' id='...'>
     >>> kall = m.mock_calls[0]
     >>> name, args, kwargs = kall
     >>> name
     'foo'
     >>> args
     (4, 5, 6)
     >>> kwargs
     {'arg': 'two', 'arg2': 'three'}
     >>> name is m.mock_calls[0][0]
     True


File: python.info,  Node: create_autospec,  Next: ANY,  Prev: call,  Up: Helpers

5.26.6.25 create_autospec
.........................

 -- Function: unittest.mock.create_autospec (spec, spec_set=False,
          instance=False, **kwargs)

     Create a mock object using another object as a spec.  Attributes on
     the mock will use the corresponding attribute on the 'spec' object
     as their spec.

     Functions or methods being mocked will have their arguments checked
     to ensure that they are called with the correct signature.

     If 'spec_set' is ‘True’ then attempting to set attributes that
     don’t exist on the spec object will raise an *note AttributeError:
     34e.

     If a class is used as a spec then the return value of the mock (the
     instance of the class) will have the same spec.  You can use a
     class as the spec for an instance object by passing
     ‘instance=True’.  The returned mock will only be callable if
     instances of the mock are callable.

     ‘create_autospec()’ also takes arbitrary keyword arguments that are
     passed to the constructor of the created mock.

See *note Autospeccing: 4301. for examples of how to use auto-speccing
with *note create_autospec(): 1712. and the 'autospec' argument to *note
patch(): ec6.

Changed in version 3.8: *note create_autospec(): 1712. now returns an
*note AsyncMock: a57. if the target is an async function.


File: python.info,  Node: ANY,  Next: FILTER_DIR,  Prev: create_autospec,  Up: Helpers

5.26.6.26 ANY
.............

 -- Data: unittest.mock.ANY

Sometimes you may need to make assertions about 'some' of the arguments
in a call to mock, but either not care about some of the arguments or
want to pull them individually out of *note call_args: 1b12. and make
more complex assertions on them.

To ignore certain arguments you can pass in objects that compare equal
to 'everything'.  Calls to *note assert_called_with(): 1bb2. and *note
assert_called_once_with(): 4308. will then succeed no matter what was
passed in.

     >>> mock = Mock(return_value=None)
     >>> mock('foo', bar=object())
     >>> mock.assert_called_once_with('foo', bar=ANY)

*note ANY: 1b5c. can also be used in comparisons with call lists like
*note mock_calls: 430a.:

     >>> m = MagicMock(return_value=None)
     >>> m(1)
     >>> m(1, 2)
     >>> m(object())
     >>> m.mock_calls == [call(1), call(1, 2), ANY]
     True

*note ANY: 1b5c. is not limited to comparisons with call objects and so
can also be used in test assertions:

     class TestStringMethods(unittest.TestCase):

         def test_split(self):
             s = 'hello world'
             self.assertEqual(s.split(), ['hello', ANY])


File: python.info,  Node: FILTER_DIR,  Next: mock_open,  Prev: ANY,  Up: Helpers

5.26.6.27 FILTER_DIR
....................

 -- Data: unittest.mock.FILTER_DIR

*note FILTER_DIR: 430e. is a module level variable that controls the way
mock objects respond to *note dir(): 635.  The default is ‘True’, which
uses the filtering described below, to only show useful members.  If you
dislike this filtering, or need to switch it off for diagnostic
purposes, then set ‘mock.FILTER_DIR = False’.

With filtering on, ‘dir(some_mock)’ shows only useful attributes and
will include any dynamically created attributes that wouldn’t normally
be shown.  If the mock was created with a 'spec' (or 'autospec' of
course) then all the attributes from the original are shown, even if
they haven’t been accessed yet:

     >>> dir(Mock())
     ['assert_any_call',
      'assert_called',
      'assert_called_once',
      'assert_called_once_with',
      'assert_called_with',
      'assert_has_calls',
      'assert_not_called',
      'attach_mock',
      ...
     >>> from urllib import request
     >>> dir(Mock(spec=request))
     ['AbstractBasicAuthHandler',
      'AbstractDigestAuthHandler',
      'AbstractHTTPHandler',
      'BaseHandler',
      ...

Many of the not-very-useful (private to *note Mock: a58. rather than the
thing being mocked) underscore and double underscore prefixed attributes
have been filtered from the result of calling *note dir(): 635. on a
‘Mock’.  If you dislike this behaviour you can switch it off by setting
the module level switch *note FILTER_DIR: 430e.:

     >>> from unittest import mock
     >>> mock.FILTER_DIR = False
     >>> dir(mock.Mock())
     ['_NonCallableMock__get_return_value',
      '_NonCallableMock__get_side_effect',
      '_NonCallableMock__return_value_doc',
      '_NonCallableMock__set_return_value',
      '_NonCallableMock__set_side_effect',
      '__call__',
      '__class__',
      ...

Alternatively you can just use ‘vars(my_mock)’ (instance members) and
‘dir(type(my_mock))’ (type members) to bypass the filtering irrespective
of *note FILTER_DIR: 430e.


File: python.info,  Node: mock_open,  Next: Autospeccing,  Prev: FILTER_DIR,  Up: Helpers

5.26.6.28 mock_open
...................

 -- Function: unittest.mock.mock_open (mock=None, read_data=None)

     A helper function to create a mock to replace the use of *note
     open(): 51f.  It works for ‘open()’ called directly or used as a
     context manager.

     The 'mock' argument is the mock object to configure.  If ‘None’
     (the default) then a *note MagicMock: ec3. will be created for you,
     with the API limited to methods or attributes available on standard
     file handles.

     'read_data' is a string for the *note read(): e4e, *note
     readline(): 1373, and *note readlines(): 24e7. methods of the file
     handle to return.  Calls to those methods will take data from
     'read_data' until it is depleted.  The mock of these methods is
     pretty simplistic: every time the 'mock' is called, the 'read_data'
     is rewound to the start.  If you need more control over the data
     that you are feeding to the tested code you will need to customize
     this mock for yourself.  When that is insufficient, one of the
     in-memory filesystem packages on PyPI(1) can offer a realistic
     filesystem for testing.

     Changed in version 3.4: Added *note readline(): 1373. and *note
     readlines(): 24e7. support.  The mock of *note read(): e4e. changed
     to consume 'read_data' rather than returning it on each call.

     Changed in version 3.5: 'read_data' is now reset on each call to
     the 'mock'.

     Changed in version 3.8: Added *note __iter__(): 1e62. to
     implementation so that iteration (such as in for loops) correctly
     consumes 'read_data'.

Using *note open(): 51f. as a context manager is a great way to ensure
your file handles are closed properly and is becoming common:

     with open('/some/path', 'w') as f:
         f.write('something')

The issue is that even if you mock out the call to *note open(): 51f. it
is the 'returned object' that is used as a context manager (and has
*note __enter__(): 5cb. and *note __exit__(): 1349. called).

Mocking context managers with a *note MagicMock: ec3. is common enough
and fiddly enough that a helper function is useful.

     >>> m = mock_open()
     >>> with patch('__main__.open', m):
     ...     with open('foo', 'w') as h:
     ...         h.write('some stuff')
     ...
     >>> m.mock_calls
     [call('foo', 'w'),
      call().__enter__(),
      call().write('some stuff'),
      call().__exit__(None, None, None)]
     >>> m.assert_called_once_with('foo', 'w')
     >>> handle = m()
     >>> handle.write.assert_called_once_with('some stuff')

And for reading files:

     >>> with patch('__main__.open', mock_open(read_data='bibble')) as m:
     ...     with open('foo') as h:
     ...         result = h.read()
     ...
     >>> m.assert_called_once_with('foo')
     >>> assert result == 'bibble'

   ---------- Footnotes ----------

   (1) https://pypi.org


File: python.info,  Node: Autospeccing,  Next: Sealing mocks,  Prev: mock_open,  Up: Helpers

5.26.6.29 Autospeccing
......................

Autospeccing is based on the existing ‘spec’ feature of mock.  It limits
the api of mocks to the api of an original object (the spec), but it is
recursive (implemented lazily) so that attributes of mocks only have the
same api as the attributes of the spec.  In addition mocked functions /
methods have the same call signature as the original so they raise a
*note TypeError: 2c3. if they are called incorrectly.

Before I explain how auto-speccing works, here’s why it is needed.

*note Mock: a58. is a very powerful and flexible object, but it suffers
from a flaw which is general to mocking.  If you refactor some of your
code, rename members and so on, any tests for code that is still using
the 'old api' but uses mocks instead of the real objects will still
pass.  This means your tests can all pass even though your code is
broken.

Changed in version 3.5: Before 3.5, tests with a typo in the word assert
would silently pass when they should raise an error.  You can still
achieve this behavior by passing ‘unsafe=True’ to Mock.

Note that this is another reason why you need integration tests as well
as unit tests.  Testing everything in isolation is all fine and dandy,
but if you don’t test how your units are “wired together” there is still
lots of room for bugs that tests might have caught.

‘unittest.mock’ already provides a feature to help with this, called
speccing.  If you use a class or instance as the ‘spec’ for a mock then
you can only access attributes on the mock that exist on the real class:

     >>> from urllib import request
     >>> mock = Mock(spec=request.Request)
     >>> mock.assret_called_with  # Intentional typo!
     Traceback (most recent call last):
      ...
     AttributeError: Mock object has no attribute 'assret_called_with'

The spec only applies to the mock itself, so we still have the same
issue with any methods on the mock:

     >>> mock.header_items()
     <mock.Mock object at 0x...>
     >>> mock.header_items.assret_called_with()  # Intentional typo!

Auto-speccing solves this problem.  You can either pass ‘autospec=True’
to *note patch(): ec6. / *note patch.object(): 169e. or use the *note
create_autospec(): 1712. function to create a mock with a spec.  If you
use the ‘autospec=True’ argument to ‘patch()’ then the object that is
being replaced will be used as the spec object.  Because the speccing is
done “lazily” (the spec is created as attributes on the mock are
accessed) you can use it with very complex or deeply nested objects
(like modules that import modules that import modules) without a big
performance hit.

Here’s an example of it in use:

     >>> from urllib import request
     >>> patcher = patch('__main__.request', autospec=True)
     >>> mock_request = patcher.start()
     >>> request is mock_request
     True
     >>> mock_request.Request
     <MagicMock name='request.Request' spec='Request' id='...'>

You can see that ‘request.Request’ has a spec.  ‘request.Request’ takes
two arguments in the constructor (one of which is 'self').  Here’s what
happens if we try to call it incorrectly:

     >>> req = request.Request()
     Traceback (most recent call last):
      ...
     TypeError: <lambda>() takes at least 2 arguments (1 given)

The spec also applies to instantiated classes (i.e.  the return value of
specced mocks):

     >>> req = request.Request('foo')
     >>> req
     <NonCallableMagicMock name='request.Request()' spec='Request' id='...'>

‘Request’ objects are not callable, so the return value of instantiating
our mocked out ‘request.Request’ is a non-callable mock.  With the spec
in place any typos in our asserts will raise the correct error:

     >>> req.add_header('spam', 'eggs')
     <MagicMock name='request.Request().add_header()' id='...'>
     >>> req.add_header.assret_called_with  # Intentional typo!
     Traceback (most recent call last):
      ...
     AttributeError: Mock object has no attribute 'assret_called_with'
     >>> req.add_header.assert_called_with('spam', 'eggs')

In many cases you will just be able to add ‘autospec=True’ to your
existing *note patch(): ec6. calls and then be protected against bugs
due to typos and api changes.

As well as using 'autospec' through *note patch(): ec6. there is a *note
create_autospec(): 1712. for creating autospecced mocks directly:

     >>> from urllib import request
     >>> mock_request = create_autospec(request)
     >>> mock_request.Request('foo', 'bar')
     <NonCallableMagicMock name='mock.Request()' spec='Request' id='...'>

This isn’t without caveats and limitations however, which is why it is
not the default behaviour.  In order to know what attributes are
available on the spec object, autospec has to introspect (access
attributes) the spec.  As you traverse attributes on the mock a
corresponding traversal of the original object is happening under the
hood.  If any of your specced objects have properties or descriptors
that can trigger code execution then you may not be able to use
autospec.  On the other hand it is much better to design your objects so
that introspection is safe (1).

A more serious problem is that it is common for instance attributes to
be created in the *note __init__(): 6b3. method and not to exist on the
class at all.  'autospec' can’t know about any dynamically created
attributes and restricts the api to visible attributes.

     >>> class Something:
     ...   def __init__(self):
     ...     self.a = 33
     ...
     >>> with patch('__main__.Something', autospec=True):
     ...   thing = Something()
     ...   thing.a
     ...
     Traceback (most recent call last):
       ...
     AttributeError: Mock object has no attribute 'a'

There are a few different ways of resolving this problem.  The easiest,
but not necessarily the least annoying, way is to simply set the
required attributes on the mock after creation.  Just because 'autospec'
doesn’t allow you to fetch attributes that don’t exist on the spec it
doesn’t prevent you setting them:

     >>> with patch('__main__.Something', autospec=True):
     ...   thing = Something()
     ...   thing.a = 33
     ...

There is a more aggressive version of both 'spec' and 'autospec' that
'does' prevent you setting non-existent attributes.  This is useful if
you want to ensure your code only 'sets' valid attributes too, but
obviously it prevents this particular scenario:

     >>> with patch('__main__.Something', autospec=True, spec_set=True):
     ...   thing = Something()
     ...   thing.a = 33
     ...
     Traceback (most recent call last):
      ...
     AttributeError: Mock object has no attribute 'a'

Probably the best way of solving the problem is to add class attributes
as default values for instance members initialised in *note __init__():
6b3.  Note that if you are only setting default attributes in
‘__init__()’ then providing them via class attributes (shared between
instances of course) is faster too.  e.g.

     class Something:
         a = 33

This brings up another issue.  It is relatively common to provide a
default value of ‘None’ for members that will later be an object of a
different type.  ‘None’ would be useless as a spec because it wouldn’t
let you access 'any' attributes or methods on it.  As ‘None’ is 'never'
going to be useful as a spec, and probably indicates a member that will
normally of some other type, autospec doesn’t use a spec for members
that are set to ‘None’.  These will just be ordinary mocks (well -
MagicMocks):

     >>> class Something:
     ...     member = None
     ...
     >>> mock = create_autospec(Something)
     >>> mock.member.foo.bar.baz()
     <MagicMock name='mock.member.foo.bar.baz()' id='...'>

If modifying your production classes to add defaults isn’t to your
liking then there are more options.  One of these is simply to use an
instance as the spec rather than the class.  The other is to create a
subclass of the production class and add the defaults to the subclass
without affecting the production class.  Both of these require you to
use an alternative object as the spec.  Thankfully *note patch(): ec6.
supports this - you can simply pass the alternative object as the
'autospec' argument:

     >>> class Something:
     ...   def __init__(self):
     ...     self.a = 33
     ...
     >>> class SomethingForTest(Something):
     ...   a = 33
     ...
     >>> p = patch('__main__.Something', autospec=SomethingForTest)
     >>> mock = p.start()
     >>> mock.a
     <NonCallableMagicMock name='Something.a' spec='int' id='...'>

   ---------- Footnotes ----------

   (1) This only applies to classes or already instantiated objects.
Calling a mocked class to create a mock instance 'does not' create a
real instance.  It is only attribute lookups - along with calls to *note
dir(): 635. - that are done.


File: python.info,  Node: Sealing mocks,  Prev: Autospeccing,  Up: Helpers

5.26.6.30 Sealing mocks
.......................

 -- Function: unittest.mock.seal (mock)

     Seal will disable the automatic creation of mocks when accessing an
     attribute of the mock being sealed or any of its attributes that
     are already mocks recursively.

     If a mock instance with a name or a spec is assigned to an
     attribute it won’t be considered in the sealing chain.  This allows
     one to prevent seal from fixing part of the mock object.

          >>> mock = Mock()
          >>> mock.submock.attribute1 = 2
          >>> mock.not_submock = mock.Mock(name="sample_name")
          >>> seal(mock)
          >>> mock.new_attribute  # This will raise AttributeError.
          >>> mock.submock.attribute2  # This will raise AttributeError.
          >>> mock.not_submock.attribute2  # This won't raise.

     Added in version 3.7.


File: python.info,  Node: Order of precedence of side_effect return_value and wraps,  Prev: Helpers,  Up: unittest mock — mock object library

5.26.6.31 Order of precedence of ‘side_effect’, ‘return_value’ and 'wraps'
..........................................................................

The order of their precedence is:

  1. *note side_effect: 42fe.

  2. *note return_value: 4306.

  3. 'wraps'

If all three are set, mock will return the value from *note side_effect:
42fe, ignoring *note return_value: 4306. and the wrapped object
altogether.  If any two are set, the one with the higher precedence will
return the value.  Regardless of the order of which was set first, the
order of precedence remains unchanged.

     >>> from unittest.mock import Mock
     >>> class Order:
     ...     @staticmethod
     ...     def get_value():
     ...         return "third"
     ...
     >>> order_mock = Mock(spec=Order, wraps=Order)
     >>> order_mock.get_value.side_effect = ["first"]
     >>> order_mock.get_value.return_value = "second"
     >>> order_mock.get_value()
     'first'

As ‘None’ is the default value of *note side_effect: 42fe, if you
reassign its value back to ‘None’, the order of precedence will be
checked between *note return_value: 4306. and the wrapped object,
ignoring ‘side_effect’.

     >>> order_mock.get_value.side_effect = None
     >>> order_mock.get_value()
     'second'

If the value being returned by *note side_effect: 42fe. is *note
DEFAULT: 4305, it is ignored and the order of precedence moves to the
successor to obtain the value to return.

     >>> from unittest.mock import DEFAULT
     >>> order_mock.get_value.side_effect = [DEFAULT]
     >>> order_mock.get_value()
     'second'

When *note Mock: a58. wraps an object, the default value of *note
return_value: 4306. will be *note DEFAULT: 4305.

     >>> order_mock = Mock(spec=Order, wraps=Order)
     >>> order_mock.return_value
     sentinel.DEFAULT
     >>> order_mock.get_value.return_value
     sentinel.DEFAULT

The order of precedence will ignore this value and it will move to the
last successor which is the wrapped object.

As the real call is being made to the wrapped object, creating an
instance of this mock will return the real instance of the class.  The
positional arguments, if any, required by the wrapped object must be
passed.

     >>> order_mock_instance = order_mock()
     >>> isinstance(order_mock_instance, Order)
     True
     >>> order_mock_instance.get_value()
     'third'

     >>> order_mock.get_value.return_value = DEFAULT
     >>> order_mock.get_value()
     'third'

     >>> order_mock.get_value.return_value = "second"
     >>> order_mock.get_value()
     'second'

But if you assign ‘None’ to it, this will not be ignored as it is an
explicit assignment.  So, the order of precedence will not move to the
wrapped object.

     >>> order_mock.get_value.return_value = None
     >>> order_mock.get_value() is None
     True

Even if you set all three at once when initializing the mock, the order
of precedence remains the same:

     >>> order_mock = Mock(spec=Order, wraps=Order,
     ...                   **{"get_value.side_effect": ["first"],
     ...                      "get_value.return_value": "second"}
     ...                   )
     ...
     >>> order_mock.get_value()
     'first'
     >>> order_mock.get_value.side_effect = None
     >>> order_mock.get_value()
     'second'
     >>> order_mock.get_value.return_value = DEFAULT
     >>> order_mock.get_value()
     'third'

If *note side_effect: 42fe. is exhausted, the order of precedence will
not cause a value to be obtained from the successors.  Instead,
‘StopIteration’ exception is raised.

     >>> order_mock = Mock(spec=Order, wraps=Order)
     >>> order_mock.get_value.side_effect = ["first side effect value",
     ...                                     "another side effect value"]
     >>> order_mock.get_value.return_value = "second"

     >>> order_mock.get_value()
     'first side effect value'
     >>> order_mock.get_value()
     'another side effect value'

     >>> order_mock.get_value()
     Traceback (most recent call last):
      ...
     StopIteration


File: python.info,  Node: unittest mock — getting started,  Next: test — Regression tests package for Python,  Prev: unittest mock — mock object library,  Up: Development Tools

5.26.7 ‘unittest.mock’ — getting started
----------------------------------------

Added in version 3.3.

* Menu:

* Using Mock::
* Patch decorators::
* Further examples::


File: python.info,  Node: Using Mock,  Next: Patch decorators,  Up: unittest mock — getting started

5.26.7.1 Using Mock
...................

* Menu:

* Mock patching methods::
* Mock for method calls on an object::
* Mocking classes::
* Naming your mocks::
* Tracking all calls::
* Setting return values and attributes::
* Raising exceptions with mocks::
* Side effect functions and iterables::
* Mocking asynchronous iterators::
* Mocking asynchronous context manager::
* Creating a mock from an existing object::
* Using side_effect to return per file content::


File: python.info,  Node: Mock patching methods,  Next: Mock for method calls on an object,  Up: Using Mock

5.26.7.2 Mock patching methods
..............................

Common uses for *note Mock: a58. objects include:

   * Patching methods

   * Recording method calls on objects

You might want to replace a method on an object to check that it is
called with the correct arguments by another part of the system:

     >>> real = SomeClass()
     >>> real.method = MagicMock(name='method')
     >>> real.method(3, 4, 5, key='value')
     <MagicMock name='method()' id='...'>

Once our mock has been used (‘real.method’ in this example) it has
methods and attributes that allow you to make assertions about how it
has been used.

     Note: In most of these examples the *note Mock: a58. and *note
     MagicMock: ec3. classes are interchangeable.  As the ‘MagicMock’ is
     the more capable class it makes a sensible one to use by default.

Once the mock has been called its *note called: 4310. attribute is set
to ‘True’.  More importantly we can use the *note assert_called_with():
1bb2. or *note assert_called_once_with(): 4308. method to check that it
was called with the correct arguments.

This example tests that calling ‘ProductionClass().method’ results in a
call to the ‘something’ method:

     >>> class ProductionClass:
     ...     def method(self):
     ...         self.something(1, 2, 3)
     ...     def something(self, a, b, c):
     ...         pass
     ...
     >>> real = ProductionClass()
     >>> real.something = MagicMock()
     >>> real.method()
     >>> real.something.assert_called_once_with(1, 2, 3)


File: python.info,  Node: Mock for method calls on an object,  Next: Mocking classes,  Prev: Mock patching methods,  Up: Using Mock

5.26.7.3 Mock for method calls on an object
...........................................

In the last example we patched a method directly on an object to check
that it was called correctly.  Another common use case is to pass an
object into a method (or some part of the system under test) and then
check that it is used in the correct way.

The simple ‘ProductionClass’ below has a ‘closer’ method.  If it is
called with an object then it calls ‘close’ on it.

     >>> class ProductionClass:
     ...     def closer(self, something):
     ...         something.close()
     ...

So to test it we need to pass in an object with a ‘close’ method and
check that it was called correctly.

     >>> real = ProductionClass()
     >>> mock = Mock()
     >>> real.closer(mock)
     >>> mock.close.assert_called_with()

We don’t have to do any work to provide the ‘close’ method on our mock.
Accessing close creates it.  So, if ‘close’ hasn’t already been called
then accessing it in the test will create it, but *note
assert_called_with(): 1bb2. will raise a failure exception.


File: python.info,  Node: Mocking classes,  Next: Naming your mocks,  Prev: Mock for method calls on an object,  Up: Using Mock

5.26.7.4 Mocking classes
........................

A common use case is to mock out classes instantiated by your code under
test.  When you patch a class, then that class is replaced with a mock.
Instances are created by 'calling the class'.  This means you access the
“mock instance” by looking at the return value of the mocked class.

In the example below we have a function ‘some_function’ that
instantiates ‘Foo’ and calls a method on it.  The call to *note patch():
ec6. replaces the class ‘Foo’ with a mock.  The ‘Foo’ instance is the
result of calling the mock, so it is configured by modifying the mock
*note return_value: 4306.

     >>> def some_function():
     ...     instance = module.Foo()
     ...     return instance.method()
     ...
     >>> with patch('module.Foo') as mock:
     ...     instance = mock.return_value
     ...     instance.method.return_value = 'the result'
     ...     result = some_function()
     ...     assert result == 'the result'


File: python.info,  Node: Naming your mocks,  Next: Tracking all calls,  Prev: Mocking classes,  Up: Using Mock

5.26.7.5 Naming your mocks
..........................

It can be useful to give your mocks a name.  The name is shown in the
repr of the mock and can be helpful when the mock appears in test
failure messages.  The name is also propagated to attributes or methods
of the mock:

     >>> mock = MagicMock(name='foo')
     >>> mock
     <MagicMock name='foo' id='...'>
     >>> mock.method
     <MagicMock name='foo.method' id='...'>


File: python.info,  Node: Tracking all calls,  Next: Setting return values and attributes,  Prev: Naming your mocks,  Up: Using Mock

5.26.7.6 Tracking all calls
...........................

Often you want to track more than a single call to a method.  The *note
mock_calls: 430a. attribute records all calls to child attributes of the
mock - and also to their children.

     >>> mock = MagicMock()
     >>> mock.method()
     <MagicMock name='mock.method()' id='...'>
     >>> mock.attribute.method(10, x=53)
     <MagicMock name='mock.attribute.method()' id='...'>
     >>> mock.mock_calls
     [call.method(), call.attribute.method(10, x=53)]

If you make an assertion about ‘mock_calls’ and any unexpected methods
have been called, then the assertion will fail.  This is useful because
as well as asserting that the calls you expected have been made, you are
also checking that they were made in the right order and with no
additional calls:

You use the *note call: 1b5e. object to construct lists for comparing
with ‘mock_calls’:

     >>> expected = [call.method(), call.attribute.method(10, x=53)]
     >>> mock.mock_calls == expected
     True

However, parameters to calls that return mocks are not recorded, which
means it is not possible to track nested calls where the parameters used
to create ancestors are important:

     >>> m = Mock()
     >>> m.factory(important=True).deliver()
     <Mock name='mock.factory().deliver()' id='...'>
     >>> m.mock_calls[-1] == call.factory(important=False).deliver()
     True


File: python.info,  Node: Setting return values and attributes,  Next: Raising exceptions with mocks,  Prev: Tracking all calls,  Up: Using Mock

5.26.7.7 Setting return values and attributes
.............................................

Setting the return values on a mock object is trivially easy:

     >>> mock = Mock()
     >>> mock.return_value = 3
     >>> mock()
     3

Of course you can do the same for methods on the mock:

     >>> mock = Mock()
     >>> mock.method.return_value = 3
     >>> mock.method()
     3

The return value can also be set in the constructor:

     >>> mock = Mock(return_value=3)
     >>> mock()
     3

If you need an attribute setting on your mock, just do it:

     >>> mock = Mock()
     >>> mock.x = 3
     >>> mock.x
     3

Sometimes you want to mock up a more complex situation, like for example
‘mock.connection.cursor().execute("SELECT 1")’.  If we wanted this call
to return a list, then we have to configure the result of the nested
call.

We can use *note call: 1b5e. to construct the set of calls in a “chained
call” like this for easy assertion afterwards:

     >>> mock = Mock()
     >>> cursor = mock.connection.cursor.return_value
     >>> cursor.execute.return_value = ['foo']
     >>> mock.connection.cursor().execute("SELECT 1")
     ['foo']
     >>> expected = call.connection.cursor().execute("SELECT 1").call_list()
     >>> mock.mock_calls
     [call.connection.cursor(), call.connection.cursor().execute('SELECT 1')]
     >>> mock.mock_calls == expected
     True

It is the call to ‘.call_list()’ that turns our call object into a list
of calls representing the chained calls.


File: python.info,  Node: Raising exceptions with mocks,  Next: Side effect functions and iterables,  Prev: Setting return values and attributes,  Up: Using Mock

5.26.7.8 Raising exceptions with mocks
......................................

A useful attribute is *note side_effect: 42fe.  If you set this to an
exception class or instance then the exception will be raised when the
mock is called.

     >>> mock = Mock(side_effect=Exception('Boom!'))
     >>> mock()
     Traceback (most recent call last):
       ...
     Exception: Boom!


File: python.info,  Node: Side effect functions and iterables,  Next: Mocking asynchronous iterators,  Prev: Raising exceptions with mocks,  Up: Using Mock

5.26.7.9 Side effect functions and iterables
............................................

‘side_effect’ can also be set to a function or an iterable.  The use
case for ‘side_effect’ as an iterable is where your mock is going to be
called several times, and you want each call to return a different
value.  When you set ‘side_effect’ to an iterable every call to the mock
returns the next value from the iterable:

     >>> mock = MagicMock(side_effect=[4, 5, 6])
     >>> mock()
     4
     >>> mock()
     5
     >>> mock()
     6

For more advanced use cases, like dynamically varying the return values
depending on what the mock is called with, ‘side_effect’ can be a
function.  The function will be called with the same arguments as the
mock.  Whatever the function returns is what the call returns:

     >>> vals = {(1, 2): 1, (2, 3): 2}
     >>> def side_effect(*args):
     ...     return vals[args]
     ...
     >>> mock = MagicMock(side_effect=side_effect)
     >>> mock(1, 2)
     1
     >>> mock(2, 3)
     2


File: python.info,  Node: Mocking asynchronous iterators,  Next: Mocking asynchronous context manager,  Prev: Side effect functions and iterables,  Up: Using Mock

5.26.7.10 Mocking asynchronous iterators
........................................

Since Python 3.8, ‘AsyncMock’ and ‘MagicMock’ have support to mock *note
Asynchronous Iterators: da5. through ‘__aiter__’.  The *note
return_value: 4306. attribute of ‘__aiter__’ can be used to set the
return values to be used for iteration.

     >>> mock = MagicMock()  # AsyncMock also works here
     >>> mock.__aiter__.return_value = [1, 2, 3]
     >>> async def main():
     ...     return [i async for i in mock]
     ...
     >>> asyncio.run(main())
     [1, 2, 3]


File: python.info,  Node: Mocking asynchronous context manager,  Next: Creating a mock from an existing object,  Prev: Mocking asynchronous iterators,  Up: Using Mock

5.26.7.11 Mocking asynchronous context manager
..............................................

Since Python 3.8, ‘AsyncMock’ and ‘MagicMock’ have support to mock *note
Asynchronous Context Managers: 5ff. through ‘__aenter__’ and
‘__aexit__’.  By default, ‘__aenter__’ and ‘__aexit__’ are ‘AsyncMock’
instances that return an async function.

     >>> class AsyncContextManager:
     ...     async def __aenter__(self):
     ...         return self
     ...     async def __aexit__(self, exc_type, exc, tb):
     ...         pass
     ...
     >>> mock_instance = MagicMock(AsyncContextManager())  # AsyncMock also works here
     >>> async def main():
     ...     async with mock_instance as result:
     ...         pass
     ...
     >>> asyncio.run(main())
     >>> mock_instance.__aenter__.assert_awaited_once()
     >>> mock_instance.__aexit__.assert_awaited_once()


File: python.info,  Node: Creating a mock from an existing object,  Next: Using side_effect to return per file content,  Prev: Mocking asynchronous context manager,  Up: Using Mock

5.26.7.12 Creating a mock from an existing object
.................................................

One problem with over use of mocking is that it couples your tests to
the implementation of your mocks rather than your real code.  Suppose
you have a class that implements ‘some_method’.  In a test for another
class, you provide a mock of this object that 'also' provides
‘some_method’.  If later you refactor the first class, so that it no
longer has ‘some_method’ - then your tests will continue to pass even
though your code is now broken!

*note Mock: a58. allows you to provide an object as a specification for
the mock, using the 'spec' keyword argument.  Accessing methods /
attributes on the mock that don’t exist on your specification object
will immediately raise an attribute error.  If you change the
implementation of your specification, then tests that use that class
will start failing immediately without you having to instantiate the
class in those tests.

     >>> mock = Mock(spec=SomeClass)
     >>> mock.old_method()
     Traceback (most recent call last):
        ...
     AttributeError: Mock object has no attribute 'old_method'. Did you mean: 'class_method'?

Using a specification also enables a smarter matching of calls made to
the mock, regardless of whether some parameters were passed as
positional or named arguments:

     >>> def f(a, b, c): pass
     ...
     >>> mock = Mock(spec=f)
     >>> mock(1, 2, 3)
     <Mock name='mock()' id='140161580456576'>
     >>> mock.assert_called_with(a=1, b=2, c=3)

If you want this smarter matching to also work with method calls on the
mock, you can use *note auto-speccing: 4301.

If you want a stronger form of specification that prevents the setting
of arbitrary attributes as well as the getting of them then you can use
'spec_set' instead of 'spec'.


File: python.info,  Node: Using side_effect to return per file content,  Prev: Creating a mock from an existing object,  Up: Using Mock

5.26.7.13 Using side_effect to return per file content
......................................................

*note mock_open(): 1022. is used to patch *note open(): 51f. method.
*note side_effect: 42fe. can be used to return a new Mock object per
call.  This can be used to return different contents per file stored in
a dictionary:

     DEFAULT = "default"
     data_dict = {"file1": "data1",
                  "file2": "data2"}

     def open_side_effect(name):
         return mock_open(read_data=data_dict.get(name, DEFAULT))()

     with patch("builtins.open", side_effect=open_side_effect):
         with open("file1") as file1:
             assert file1.read() == "data1"

         with open("file2") as file2:
             assert file2.read() == "data2"

         with open("file3") as file2:
             assert file2.read() == "default"


File: python.info,  Node: Patch decorators,  Next: Further examples,  Prev: Using Mock,  Up: unittest mock — getting started

5.26.7.14 Patch decorators
..........................

     Note: With *note patch(): ec6. it matters that you patch objects in
     the namespace where they are looked up.  This is normally
     straightforward, but for a quick guide read *note where to patch:
     42ff.

A common need in tests is to patch a class attribute or a module
attribute, for example patching a builtin or patching a class in a
module to test that it is instantiated.  Modules and classes are
effectively global, so patching on them has to be undone after the test
or the patch will persist into other tests and cause hard to diagnose
problems.

mock provides three convenient decorators for this: *note patch(): ec6,
*note patch.object(): 169e. and *note patch.dict(): 1b83.  ‘patch’ takes
a single string, of the form ‘package.module.Class.attribute’ to specify
the attribute you are patching.  It also optionally takes a value that
you want the attribute (or class or whatever) to be replaced with.
‘patch.object’ takes an object and the name of the attribute you would
like patched, plus optionally the value to patch it with.

‘patch.object’:

     >>> original = SomeClass.attribute
     >>> @patch.object(SomeClass, 'attribute', sentinel.attribute)
     ... def test():
     ...     assert SomeClass.attribute == sentinel.attribute
     ...
     >>> test()
     >>> assert SomeClass.attribute == original

     >>> @patch('package.module.attribute', sentinel.attribute)
     ... def test():
     ...     from package.module import attribute
     ...     assert attribute is sentinel.attribute
     ...
     >>> test()

If you are patching a module (including *note builtins: 12.) then use
*note patch(): ec6. instead of *note patch.object(): 169e.:

     >>> mock = MagicMock(return_value=sentinel.file_handle)
     >>> with patch('builtins.open', mock):
     ...     handle = open('filename', 'r')
     ...
     >>> mock.assert_called_with('filename', 'r')
     >>> assert handle == sentinel.file_handle, "incorrect file handle returned"

The module name can be ‘dotted’, in the form ‘package.module’ if needed:

     >>> @patch('package.module.ClassName.attribute', sentinel.attribute)
     ... def test():
     ...     from package.module import ClassName
     ...     assert ClassName.attribute == sentinel.attribute
     ...
     >>> test()

A nice pattern is to actually decorate test methods themselves:

     >>> class MyTest(unittest.TestCase):
     ...     @patch.object(SomeClass, 'attribute', sentinel.attribute)
     ...     def test_something(self):
     ...         self.assertEqual(SomeClass.attribute, sentinel.attribute)
     ...
     >>> original = SomeClass.attribute
     >>> MyTest('test_something').test_something()
     >>> assert SomeClass.attribute == original

If you want to patch with a Mock, you can use *note patch(): ec6. with
only one argument (or *note patch.object(): 169e. with two arguments).
The mock will be created for you and passed into the test function /
method:

     >>> class MyTest(unittest.TestCase):
     ...     @patch.object(SomeClass, 'static_method')
     ...     def test_something(self, mock_method):
     ...         SomeClass.static_method()
     ...         mock_method.assert_called_with()
     ...
     >>> MyTest('test_something').test_something()

You can stack up multiple patch decorators using this pattern:

     >>> class MyTest(unittest.TestCase):
     ...     @patch('package.module.ClassName1')
     ...     @patch('package.module.ClassName2')
     ...     def test_something(self, MockClass2, MockClass1):
     ...         self.assertIs(package.module.ClassName1, MockClass1)
     ...         self.assertIs(package.module.ClassName2, MockClass2)
     ...
     >>> MyTest('test_something').test_something()

When you nest patch decorators the mocks are passed in to the decorated
function in the same order they applied (the normal 'Python' order that
decorators are applied).  This means from the bottom up, so in the
example above the mock for ‘test_module.ClassName2’ is passed in first.

There is also *note patch.dict(): 1b83. for setting values in a
dictionary just during a scope and restoring the dictionary to its
original state when the test ends:

     >>> foo = {'key': 'value'}
     >>> original = foo.copy()
     >>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
     ...     assert foo == {'newkey': 'newvalue'}
     ...
     >>> assert foo == original

‘patch’, ‘patch.object’ and ‘patch.dict’ can all be used as context
managers.

Where you use *note patch(): ec6. to create a mock for you, you can get
a reference to the mock using the “as” form of the with statement:

     >>> class ProductionClass:
     ...     def method(self):
     ...         pass
     ...
     >>> with patch.object(ProductionClass, 'method') as mock_method:
     ...     mock_method.return_value = None
     ...     real = ProductionClass()
     ...     real.method(1, 2, 3)
     ...
     >>> mock_method.assert_called_with(1, 2, 3)

As an alternative ‘patch’, ‘patch.object’ and ‘patch.dict’ can be used
as class decorators.  When used in this way it is the same as applying
the decorator individually to every method whose name starts with
“test”.


File: python.info,  Node: Further examples,  Prev: Patch decorators,  Up: unittest mock — getting started

5.26.7.15 Further examples
..........................

Here are some more examples for some slightly more advanced scenarios.

* Menu:

* Mocking chained calls::
* Partial mocking::
* Mocking a generator method::
* Applying the same patch to every test method::
* Mocking unbound methods::
* Checking multiple calls with mock::
* Coping with mutable arguments::
* Nesting patches::
* Mocking a dictionary with MagicMock::
* Mock subclasses and their attributes::
* Mocking imports with patch.dict: Mocking imports with patch dict.
* Tracking order of calls and less verbose call assertions::
* More complex argument matching::


File: python.info,  Node: Mocking chained calls,  Next: Partial mocking,  Up: Further examples

5.26.7.16 Mocking chained calls
...............................

Mocking chained calls is actually straightforward with mock once you
understand the *note return_value: 4306. attribute.  When a mock is
called for the first time, or you fetch its ‘return_value’ before it has
been called, a new *note Mock: a58. is created.

This means that you can see how the object returned from a call to a
mocked object has been used by interrogating the ‘return_value’ mock:

     >>> mock = Mock()
     >>> mock().foo(a=2, b=3)
     <Mock name='mock().foo()' id='...'>
     >>> mock.return_value.foo.assert_called_with(a=2, b=3)

From here it is a simple step to configure and then make assertions
about chained calls.  Of course another alternative is writing your code
in a more testable way in the first place…

So, suppose we have some code that looks a little bit like this:

     >>> class Something:
     ...     def __init__(self):
     ...         self.backend = BackendProvider()
     ...     def method(self):
     ...         response = self.backend.get_endpoint('foobar').create_call('spam', 'eggs').start_call()
     ...         # more code

Assuming that ‘BackendProvider’ is already well tested, how do we test
‘method()’?  Specifically, we want to test that the code section ‘# more
code’ uses the response object in the correct way.

As this chain of calls is made from an instance attribute we can monkey
patch the ‘backend’ attribute on a ‘Something’ instance.  In this
particular case we are only interested in the return value from the
final call to ‘start_call’ so we don’t have much configuration to do.
Let’s assume the object it returns is ‘file-like’, so we’ll ensure that
our response object uses the builtin *note open(): 51f. as its ‘spec’.

To do this we create a mock instance as our mock backend and create a
mock response object for it.  To set the response as the return value
for that final ‘start_call’ we could do this:

     mock_backend.get_endpoint.return_value.create_call.return_value.start_call.return_value = mock_response

We can do that in a slightly nicer way using the *note configure_mock():
4307. method to directly set the return value for us:

     >>> something = Something()
     >>> mock_response = Mock(spec=open)
     >>> mock_backend = Mock()
     >>> config = {'get_endpoint.return_value.create_call.return_value.start_call.return_value': mock_response}
     >>> mock_backend.configure_mock(**config)

With these we monkey patch the “mock backend” in place and can make the
real call:

     >>> something.backend = mock_backend
     >>> something.method()

Using *note mock_calls: 430a. we can check the chained call with a
single assert.  A chained call is several calls in one line of code, so
there will be several entries in ‘mock_calls’.  We can use *note
call.call_list(): 4340. to create this list of calls for us:

     >>> chained = call.get_endpoint('foobar').create_call('spam', 'eggs').start_call()
     >>> call_list = chained.call_list()
     >>> assert mock_backend.mock_calls == call_list


File: python.info,  Node: Partial mocking,  Next: Mocking a generator method,  Prev: Mocking chained calls,  Up: Further examples

5.26.7.17 Partial mocking
.........................

For some tests, you may want to mock out a call to *note
datetime.date.today(): 1519. to return a known date, but don’t want to
prevent the code under test from creating new date objects.
Unfortunately *note datetime.date: 1cd. is written in C, so you cannot
just monkey-patch out the static ‘datetime.date.today()’ method.

Instead, you can effectively wrap the date class with a mock, while
passing through calls to the constructor to the real class (and
returning real instances).

The *note patch decorator: ec6. is used here to mock out the ‘date’
class in the module under test.  The *note side_effect: 42fe. attribute
on the mock date class is then set to a lambda function that returns a
real date.  When the mock date class is called a real date will be
constructed and returned by ‘side_effect’.

     >>> import datetime as dt
     >>> with patch('mymodule.date') as mock_date:
     ...     mock_date.today.return_value = dt.date(2010, 10, 8)
     ...     mock_date.side_effect = lambda *args, **kw: dt.date(*args, **kw)
     ...
     ...     assert mymodule.date.today() == dt.date(2010, 10, 8)
     ...     assert mymodule.date(2009, 6, 8) == dt.date(2009, 6, 8)

Note that we don’t patch *note datetime.date: 1cd. globally, we patch
‘date’ in the module that 'uses' it.  See *note where to patch: 42ff.

When ‘date.today()’ is called a known date is returned, but calls to the
‘date(...)’ constructor still return normal dates.  Without this you can
find yourself having to calculate an expected result using exactly the
same algorithm as the code under test, which is a classic testing
anti-pattern.

Calls to the date constructor are recorded in the ‘mock_date’ attributes
(‘call_count’ and friends) which may also be useful for your tests.

An alternative way of dealing with mocking dates, or other builtin
classes, is discussed in this blog entry(1).

   ---------- Footnotes ----------

   (1) 
https://williambert.online/2011/07/how-to-unit-testing-in-django-with-mocking-and-patching/


File: python.info,  Node: Mocking a generator method,  Next: Applying the same patch to every test method,  Prev: Partial mocking,  Up: Further examples

5.26.7.18 Mocking a generator method
....................................

A Python generator is a function or method that uses the *note yield:
9d8. statement to return a series of values when iterated over (1).

A generator method / function is called to return the generator object.
It is the generator object that is then iterated over.  The protocol
method for iteration is *note __iter__(): 1e62, so we can mock this
using a *note MagicMock: ec3.

Here’s an example class with an “iter” method implemented as a
generator:

     >>> class Foo:
     ...     def iter(self):
     ...         for i in [1, 2, 3]:
     ...             yield i
     ...
     >>> foo = Foo()
     >>> list(foo.iter())
     [1, 2, 3]

How would we mock this class, and in particular its “iter” method?

To configure the values returned from the iteration (implicit in the
call to *note list: 614.), we need to configure the object returned by
the call to ‘foo.iter()’.

     >>> mock_foo = MagicMock()
     >>> mock_foo.iter.return_value = iter([1, 2, 3])
     >>> list(mock_foo.iter())
     [1, 2, 3]

   ---------- Footnotes ----------

   (1) There are also generator expressions and more advanced uses
(http://www.dabeaz.com/coroutines/index.html) of generators, but we
aren’t concerned about them here.  A very good introduction to
generators and how powerful they are is: Generator Tricks for Systems
Programmers (http://www.dabeaz.com/generators/).


File: python.info,  Node: Applying the same patch to every test method,  Next: Mocking unbound methods,  Prev: Mocking a generator method,  Up: Further examples

5.26.7.19 Applying the same patch to every test method
......................................................

If you want several patches in place for multiple test methods the
obvious way is to apply the patch decorators to every method.  This can
feel like unnecessary repetition.  Instead, you can use *note patch():
ec6. (in all its various forms) as a class decorator.  This applies the
patches to all test methods on the class.  A test method is identified
by methods whose names start with ‘test’:

     >>> @patch('mymodule.SomeClass')
     ... class MyTest(unittest.TestCase):
     ...
     ...     def test_one(self, MockSomeClass):
     ...         self.assertIs(mymodule.SomeClass, MockSomeClass)
     ...
     ...     def test_two(self, MockSomeClass):
     ...         self.assertIs(mymodule.SomeClass, MockSomeClass)
     ...
     ...     def not_a_test(self):
     ...         return 'something'
     ...
     >>> MyTest('test_one').test_one()
     >>> MyTest('test_two').test_two()
     >>> MyTest('test_two').not_a_test()
     'something'

An alternative way of managing patches is to use the *note patch
methods; start and stop: 4331.  These allow you to move the patching
into your ‘setUp’ and ‘tearDown’ methods.

     >>> class MyTest(unittest.TestCase):
     ...     def setUp(self):
     ...         self.patcher = patch('mymodule.foo')
     ...         self.mock_foo = self.patcher.start()
     ...
     ...     def test_foo(self):
     ...         self.assertIs(mymodule.foo, self.mock_foo)
     ...
     ...     def tearDown(self):
     ...         self.patcher.stop()
     ...
     >>> MyTest('test_foo').run()

If you use this technique you must ensure that the patching is “undone”
by calling ‘stop’.  This can be fiddlier than you might think, because
if an exception is raised in the setUp then tearDown is not called.
*note unittest.TestCase.addCleanup(): a90. makes this easier:

     >>> class MyTest(unittest.TestCase):
     ...     def setUp(self):
     ...         patcher = patch('mymodule.foo')
     ...         self.addCleanup(patcher.stop)
     ...         self.mock_foo = patcher.start()
     ...
     ...     def test_foo(self):
     ...         self.assertIs(mymodule.foo, self.mock_foo)
     ...
     >>> MyTest('test_foo').run()


File: python.info,  Node: Mocking unbound methods,  Next: Checking multiple calls with mock,  Prev: Applying the same patch to every test method,  Up: Further examples

5.26.7.20 Mocking unbound methods
.................................

Sometimes a test needs to patch an 'unbound method', which means
patching the method on the class rather than on the instance.  In order
to make assertions about which objects were calling this particular
method, you need to pass ‘self’ as the first argument.  The issue is
that you can’t patch with a mock for this, because if you replace an
unbound method with a mock it doesn’t become a bound method when fetched
from the instance, and so it doesn’t get ‘self’ passed in.  The
workaround is to patch the unbound method with a real function instead.
The *note patch(): ec6. decorator makes it so simple to patch out
methods with a mock that having to create a real function becomes a
nuisance.

If you pass ‘autospec=True’ to patch then it does the patching with a
'real' function object.  This function object has the same signature as
the one it is replacing, but delegates to a mock under the hood.  You
still get your mock auto-created in exactly the same way as before.
What it means though, is that if you use it to patch out an unbound
method on a class the mocked function will be turned into a bound method
if it is fetched from an instance.  It will have ‘self’ passed in as the
first argument, which is exactly what was needed:

     >>> class Foo:
     ...   def foo(self):
     ...     pass
     ...
     >>> with patch.object(Foo, 'foo', autospec=True) as mock_foo:
     ...   mock_foo.return_value = 'foo'
     ...   foo = Foo()
     ...   foo.foo()
     ...
     'foo'
     >>> mock_foo.assert_called_once_with(foo)

If we don’t use ‘autospec=True’ then the unbound method is patched out
with a Mock instance instead, and isn’t called with ‘self’.


File: python.info,  Node: Checking multiple calls with mock,  Next: Coping with mutable arguments,  Prev: Mocking unbound methods,  Up: Further examples

5.26.7.21 Checking multiple calls with mock
...........................................

mock has a nice API for making assertions about how your mock objects
are used.

     >>> mock = Mock()
     >>> mock.foo_bar.return_value = None
     >>> mock.foo_bar('baz', spam='eggs')
     >>> mock.foo_bar.assert_called_with('baz', spam='eggs')

If your mock is only being called once you can use the *note
assert_called_once_with(): 4308. method that also asserts that the *note
call_count: 15ce. is one.

     >>> mock.foo_bar.assert_called_once_with('baz', spam='eggs')
     >>> mock.foo_bar()
     >>> mock.foo_bar.assert_called_once_with('baz', spam='eggs')
     Traceback (most recent call last):
         ...
     AssertionError: Expected 'foo_bar' to be called once. Called 2 times.
     Calls: [call('baz', spam='eggs'), call()].

Both ‘assert_called_with’ and ‘assert_called_once_with’ make assertions
about the 'most recent' call.  If your mock is going to be called
several times, and you want to make assertions about 'all' those calls
you can use *note call_args_list: 4311.:

     >>> mock = Mock(return_value=None)
     >>> mock(1, 2, 3)
     >>> mock(4, 5, 6)
     >>> mock()
     >>> mock.call_args_list
     [call(1, 2, 3), call(4, 5, 6), call()]

The *note call: 1b5e. helper makes it easy to make assertions about
these calls.  You can build up a list of expected calls and compare it
to ‘call_args_list’.  This looks remarkably similar to the repr of the
‘call_args_list’:

     >>> expected = [call(1, 2, 3), call(4, 5, 6), call()]
     >>> mock.call_args_list == expected
     True


File: python.info,  Node: Coping with mutable arguments,  Next: Nesting patches,  Prev: Checking multiple calls with mock,  Up: Further examples

5.26.7.22 Coping with mutable arguments
.......................................

Another situation is rare, but can bite you, is when your mock is called
with mutable arguments.  ‘call_args’ and ‘call_args_list’ store
'references' to the arguments.  If the arguments are mutated by the code
under test then you can no longer make assertions about what the values
were when the mock was called.

Here’s some example code that shows the problem.  Imagine the following
functions defined in ‘mymodule’:

     def frob(val):
         pass

     def grob(val):
         "First frob and then clear val"
         frob(val)
         val.clear()

When we try to test that ‘grob’ calls ‘frob’ with the correct argument
look what happens:

     >>> with patch('mymodule.frob') as mock_frob:
     ...     val = {6}
     ...     mymodule.grob(val)
     ...
     >>> val
     set()
     >>> mock_frob.assert_called_with({6})
     Traceback (most recent call last):
         ...
     AssertionError: Expected: (({6},), {})
     Called with: ((set(),), {})

One possibility would be for mock to copy the arguments you pass in.
This could then cause problems if you do assertions that rely on object
identity for equality.

Here’s one solution that uses the *note side_effect: 42fe.
functionality.  If you provide a ‘side_effect’ function for a mock then
‘side_effect’ will be called with the same args as the mock.  This gives
us an opportunity to copy the arguments and store them for later
assertions.  In this example I’m using 'another' mock to store the
arguments so that I can use the mock methods for doing the assertion.
Again a helper function sets this up for me.

     >>> from copy import deepcopy
     >>> from unittest.mock import Mock, patch, DEFAULT
     >>> def copy_call_args(mock):
     ...     new_mock = Mock()
     ...     def side_effect(*args, **kwargs):
     ...         args = deepcopy(args)
     ...         kwargs = deepcopy(kwargs)
     ...         new_mock(*args, **kwargs)
     ...         return DEFAULT
     ...     mock.side_effect = side_effect
     ...     return new_mock
     ...
     >>> with patch('mymodule.frob') as mock_frob:
     ...     new_mock = copy_call_args(mock_frob)
     ...     val = {6}
     ...     mymodule.grob(val)
     ...
     >>> new_mock.assert_called_with({6})
     >>> new_mock.call_args
     call({6})

‘copy_call_args’ is called with the mock that will be called.  It
returns a new mock that we do the assertion on.  The ‘side_effect’
function makes a copy of the args and calls our ‘new_mock’ with the
copy.

     Note: If your mock is only going to be used once there is an easier
     way of checking arguments at the point they are called.  You can
     simply do the checking inside a ‘side_effect’ function.

          >>> def side_effect(arg):
          ...     assert arg == {6}
          ...
          >>> mock = Mock(side_effect=side_effect)
          >>> mock({6})
          >>> mock(set())
          Traceback (most recent call last):
              ...
          AssertionError

An alternative approach is to create a subclass of *note Mock: a58. or
*note MagicMock: ec3. that copies (using *note copy.deepcopy(): b8a.)
the arguments.  Here’s an example implementation:

     >>> from copy import deepcopy
     >>> class CopyingMock(MagicMock):
     ...     def __call__(self, /, *args, **kwargs):
     ...         args = deepcopy(args)
     ...         kwargs = deepcopy(kwargs)
     ...         return super().__call__(*args, **kwargs)
     ...
     >>> c = CopyingMock(return_value=None)
     >>> arg = set()
     >>> c(arg)
     >>> arg.add(1)
     >>> c.assert_called_with(set())
     >>> c.assert_called_with(arg)
     Traceback (most recent call last):
         ...
     AssertionError: expected call not found.
     Expected: mock({1})
     Actual: mock(set())
     >>> c.foo
     <CopyingMock name='mock.foo' id='...'>

When you subclass ‘Mock’ or ‘MagicMock’ all dynamically created
attributes, and the ‘return_value’ will use your subclass automatically.
That means all children of a ‘CopyingMock’ will also have the type
‘CopyingMock’.


File: python.info,  Node: Nesting patches,  Next: Mocking a dictionary with MagicMock,  Prev: Coping with mutable arguments,  Up: Further examples

5.26.7.23 Nesting patches
.........................

Using patch as a context manager is nice, but if you do multiple patches
you can end up with nested with statements indenting further and further
to the right:

     >>> class MyTest(unittest.TestCase):
     ...
     ...     def test_foo(self):
     ...         with patch('mymodule.Foo') as mock_foo:
     ...             with patch('mymodule.Bar') as mock_bar:
     ...                 with patch('mymodule.Spam') as mock_spam:
     ...                     assert mymodule.Foo is mock_foo
     ...                     assert mymodule.Bar is mock_bar
     ...                     assert mymodule.Spam is mock_spam
     ...
     >>> original = mymodule.Foo
     >>> MyTest('test_foo').test_foo()
     >>> assert mymodule.Foo is original

With unittest ‘cleanup’ functions and the *note patch methods; start and
stop: 4331. we can achieve the same effect without the nested
indentation.  A simple helper method, ‘create_patch’, puts the patch in
place and returns the created mock for us:

     >>> class MyTest(unittest.TestCase):
     ...
     ...     def create_patch(self, name):
     ...         patcher = patch(name)
     ...         thing = patcher.start()
     ...         self.addCleanup(patcher.stop)
     ...         return thing
     ...
     ...     def test_foo(self):
     ...         mock_foo = self.create_patch('mymodule.Foo')
     ...         mock_bar = self.create_patch('mymodule.Bar')
     ...         mock_spam = self.create_patch('mymodule.Spam')
     ...
     ...         assert mymodule.Foo is mock_foo
     ...         assert mymodule.Bar is mock_bar
     ...         assert mymodule.Spam is mock_spam
     ...
     >>> original = mymodule.Foo
     >>> MyTest('test_foo').run()
     >>> assert mymodule.Foo is original


File: python.info,  Node: Mocking a dictionary with MagicMock,  Next: Mock subclasses and their attributes,  Prev: Nesting patches,  Up: Further examples

5.26.7.24 Mocking a dictionary with MagicMock
.............................................

You may want to mock a dictionary, or other container object, recording
all access to it whilst having it still behave like a dictionary.

We can do this with *note MagicMock: ec3, which will behave like a
dictionary, and using *note side_effect: 42fe. to delegate dictionary
access to a real underlying dictionary that is under our control.

When the *note __getitem__(): 283. and *note __setitem__(): 1313.
methods of our ‘MagicMock’ are called (normal dictionary access) then
‘side_effect’ is called with the key (and in the case of ‘__setitem__’
the value too).  We can also control what is returned.

After the ‘MagicMock’ has been used we can use attributes like *note
call_args_list: 4311. to assert about how the dictionary was used:

     >>> my_dict = {'a': 1, 'b': 2, 'c': 3}
     >>> def getitem(name):
     ...      return my_dict[name]
     ...
     >>> def setitem(name, val):
     ...     my_dict[name] = val
     ...
     >>> mock = MagicMock()
     >>> mock.__getitem__.side_effect = getitem
     >>> mock.__setitem__.side_effect = setitem

     Note: An alternative to using ‘MagicMock’ is to use ‘Mock’ and
     'only' provide the magic methods you specifically want:

          >>> mock = Mock()
          >>> mock.__getitem__ = Mock(side_effect=getitem)
          >>> mock.__setitem__ = Mock(side_effect=setitem)

     A 'third' option is to use ‘MagicMock’ but passing in ‘dict’ as the
     'spec' (or 'spec_set') argument so that the ‘MagicMock’ created
     only has dictionary magic methods available:

          >>> mock = MagicMock(spec_set=dict)
          >>> mock.__getitem__.side_effect = getitem
          >>> mock.__setitem__.side_effect = setitem

With these side effect functions in place, the ‘mock’ will behave like a
normal dictionary but recording the access.  It even raises a *note
KeyError: 345. if you try to access a key that doesn’t exist.

     >>> mock['a']
     1
     >>> mock['c']
     3
     >>> mock['d']
     Traceback (most recent call last):
         ...
     KeyError: 'd'
     >>> mock['b'] = 'fish'
     >>> mock['d'] = 'eggs'
     >>> mock['b']
     'fish'
     >>> mock['d']
     'eggs'

After it has been used you can make assertions about the access using
the normal mock methods and attributes:

     >>> mock.__getitem__.call_args_list
     [call('a'), call('c'), call('d'), call('b'), call('d')]
     >>> mock.__setitem__.call_args_list
     [call('b', 'fish'), call('d', 'eggs')]
     >>> my_dict
     {'a': 1, 'b': 'fish', 'c': 3, 'd': 'eggs'}


File: python.info,  Node: Mock subclasses and their attributes,  Next: Mocking imports with patch dict,  Prev: Mocking a dictionary with MagicMock,  Up: Further examples

5.26.7.25 Mock subclasses and their attributes
..............................................

There are various reasons why you might want to subclass *note Mock:
a58.  One reason might be to add helper methods.  Here’s a silly
example:

     >>> class MyMock(MagicMock):
     ...     def has_been_called(self):
     ...         return self.called
     ...
     >>> mymock = MyMock(return_value=None)
     >>> mymock
     <MyMock id='...'>
     >>> mymock.has_been_called()
     False
     >>> mymock()
     >>> mymock.has_been_called()
     True

The standard behaviour for ‘Mock’ instances is that attributes and the
return value mocks are of the same type as the mock they are accessed
on.  This ensures that ‘Mock’ attributes are ‘Mocks’ and ‘MagicMock’
attributes are ‘MagicMocks’ (1).  So if you’re subclassing to add helper
methods then they’ll also be available on the attributes and return
value mock of instances of your subclass.

     >>> mymock.foo
     <MyMock name='mock.foo' id='...'>
     >>> mymock.foo.has_been_called()
     False
     >>> mymock.foo()
     <MyMock name='mock.foo()' id='...'>
     >>> mymock.foo.has_been_called()
     True

Sometimes this is inconvenient.  For example, one user(2) is subclassing
mock to created a Twisted adaptor(3).  Having this applied to attributes
too actually causes errors.

‘Mock’ (in all its flavours) uses a method called ‘_get_child_mock’ to
create these “sub-mocks” for attributes and return values.  You can
prevent your subclass being used for attributes by overriding this
method.  The signature is that it takes arbitrary keyword arguments
(‘**kwargs’) which are then passed onto the mock constructor:

     >>> class Subclass(MagicMock):
     ...     def _get_child_mock(self, /, **kwargs):
     ...         return MagicMock(**kwargs)
     ...
     >>> mymock = Subclass()
     >>> mymock.foo
     <MagicMock name='mock.foo' id='...'>
     >>> assert isinstance(mymock, Subclass)
     >>> assert not isinstance(mymock.foo, Subclass)
     >>> assert not isinstance(mymock(), Subclass)

   ---------- Footnotes ----------

   (1) An exception to this rule are the non-callable mocks.  Attributes
use the callable variant because otherwise non-callable mocks couldn’t
have callable methods.

   (2) https://code.google.com/archive/p/mock/issues/105

   (3) 
https://twisted.org/documents/11.0.0/api/twisted.python.components.html


File: python.info,  Node: Mocking imports with patch dict,  Next: Tracking order of calls and less verbose call assertions,  Prev: Mock subclasses and their attributes,  Up: Further examples

5.26.7.26 Mocking imports with patch.dict
.........................................

One situation where mocking can be hard is where you have a local import
inside a function.  These are harder to mock because they aren’t using
an object from the module namespace that we can patch out.

Generally local imports are to be avoided.  They are sometimes done to
prevent circular dependencies, for which there is 'usually' a much
better way to solve the problem (refactor the code) or to prevent “up
front costs” by delaying the import.  This can also be solved in better
ways than an unconditional local import (store the module as a class or
module attribute and only do the import on first use).

That aside there is a way to use ‘mock’ to affect the results of an
import.  Importing fetches an 'object' from the *note sys.modules: 1655.
dictionary.  Note that it fetches an 'object', which need not be a
module.  Importing a module for the first time results in a module
object being put in ‘sys.modules’, so usually when you import something
you get a module back.  This need not be the case however.

This means you can use *note patch.dict(): 1b83. to 'temporarily' put a
mock in place in *note sys.modules: 1655.  Any imports whilst this patch
is active will fetch the mock.  When the patch is complete (the
decorated function exits, the with statement body is complete or
‘patcher.stop()’ is called) then whatever was there previously will be
restored safely.

Here’s an example that mocks out the ‘fooble’ module.

     >>> import sys
     >>> mock = Mock()
     >>> with patch.dict('sys.modules', {'fooble': mock}):
     ...    import fooble
     ...    fooble.blob()
     ...
     <Mock name='mock.blob()' id='...'>
     >>> assert 'fooble' not in sys.modules
     >>> mock.blob.assert_called_once_with()

As you can see the ‘import fooble’ succeeds, but on exit there is no
‘fooble’ left in *note sys.modules: 1655.

This also works for the ‘from module import name’ form:

     >>> mock = Mock()
     >>> with patch.dict('sys.modules', {'fooble': mock}):
     ...    from fooble import blob
     ...    blob.blip()
     ...
     <Mock name='mock.blob.blip()' id='...'>
     >>> mock.blob.blip.assert_called_once_with()

With slightly more work you can also mock package imports:

     >>> mock = Mock()
     >>> modules = {'package': mock, 'package.module': mock.module}
     >>> with patch.dict('sys.modules', modules):
     ...    from package.module import fooble
     ...    fooble()
     ...
     <Mock name='mock.module.fooble()' id='...'>
     >>> mock.module.fooble.assert_called_once_with()


File: python.info,  Node: Tracking order of calls and less verbose call assertions,  Next: More complex argument matching,  Prev: Mocking imports with patch dict,  Up: Further examples

5.26.7.27 Tracking order of calls and less verbose call assertions
..................................................................

The *note Mock: a58. class allows you to track the 'order' of method
calls on your mock objects through the *note method_calls: 430c.
attribute.  This doesn’t allow you to track the order of calls between
separate mock objects, however we can use *note mock_calls: 430a. to
achieve the same effect.

Because mocks track calls to child mocks in ‘mock_calls’, and accessing
an arbitrary attribute of a mock creates a child mock, we can create our
separate mocks from a parent one.  Calls to those child mock will then
all be recorded, in order, in the ‘mock_calls’ of the parent:

     >>> manager = Mock()
     >>> mock_foo = manager.foo
     >>> mock_bar = manager.bar

     >>> mock_foo.something()
     <Mock name='mock.foo.something()' id='...'>
     >>> mock_bar.other.thing()
     <Mock name='mock.bar.other.thing()' id='...'>

     >>> manager.mock_calls
     [call.foo.something(), call.bar.other.thing()]

We can then assert about the calls, including the order, by comparing
with the ‘mock_calls’ attribute on the manager mock:

     >>> expected_calls = [call.foo.something(), call.bar.other.thing()]
     >>> manager.mock_calls == expected_calls
     True

If ‘patch’ is creating, and putting in place, your mocks then you can
attach them to a manager mock using the *note attach_mock(): 1718.
method.  After attaching calls will be recorded in ‘mock_calls’ of the
manager.

     >>> manager = MagicMock()
     >>> with patch('mymodule.Class1') as MockClass1:
     ...     with patch('mymodule.Class2') as MockClass2:
     ...         manager.attach_mock(MockClass1, 'MockClass1')
     ...         manager.attach_mock(MockClass2, 'MockClass2')
     ...         MockClass1().foo()
     ...         MockClass2().bar()
     <MagicMock name='mock.MockClass1().foo()' id='...'>
     <MagicMock name='mock.MockClass2().bar()' id='...'>
     >>> manager.mock_calls
     [call.MockClass1(),
     call.MockClass1().foo(),
     call.MockClass2(),
     call.MockClass2().bar()]

If many calls have been made, but you’re only interested in a particular
sequence of them then an alternative is to use the *note
assert_has_calls(): 17ba. method.  This takes a list of calls
(constructed with the *note call: 1b5e. object).  If that sequence of
calls are in *note mock_calls: 430a. then the assert succeeds.

     >>> m = MagicMock()
     >>> m().foo().bar().baz()
     <MagicMock name='mock().foo().bar().baz()' id='...'>
     >>> m.one().two().three()
     <MagicMock name='mock.one().two().three()' id='...'>
     >>> calls = call.one().two().three().call_list()
     >>> m.assert_has_calls(calls)

Even though the chained call ‘m.one().two().three()’ aren’t the only
calls that have been made to the mock, the assert still succeeds.

Sometimes a mock may have several calls made to it, and you are only
interested in asserting about 'some' of those calls.  You may not even
care about the order.  In this case you can pass ‘any_order=True’ to
‘assert_has_calls’:

     >>> m = MagicMock()
     >>> m(1), m.two(2, 3), m.seven(7), m.fifty('50')
     (...)
     >>> calls = [call.fifty('50'), call(1), call.seven(7)]
     >>> m.assert_has_calls(calls, any_order=True)


File: python.info,  Node: More complex argument matching,  Prev: Tracking order of calls and less verbose call assertions,  Up: Further examples

5.26.7.28 More complex argument matching
........................................

Using the same basic concept as *note ANY: 1b5c. we can implement
matchers to do more complex assertions on objects used as arguments to
mocks.

Suppose we expect some object to be passed to a mock that by default
compares equal based on object identity (which is the Python default for
user defined classes).  To use *note assert_called_with(): 1bb2. we
would need to pass in the exact same object.  If we are only interested
in some of the attributes of this object then we can create a matcher
that will check these attributes for us.

You can see in this example how a ‘standard’ call to
‘assert_called_with’ isn’t sufficient:

     >>> class Foo:
     ...     def __init__(self, a, b):
     ...         self.a, self.b = a, b
     ...
     >>> mock = Mock(return_value=None)
     >>> mock(Foo(1, 2))
     >>> mock.assert_called_with(Foo(1, 2))
     Traceback (most recent call last):
         ...
     AssertionError: expected call not found.
     Expected: mock(<__main__.Foo object at 0x...>)
     Actual: mock(<__main__.Foo object at 0x...>)

A comparison function for our ‘Foo’ class might look something like
this:

     >>> def compare(self, other):
     ...     if not type(self) == type(other):
     ...         return False
     ...     if self.a != other.a:
     ...         return False
     ...     if self.b != other.b:
     ...         return False
     ...     return True
     ...

And a matcher object that can use comparison functions like this for its
equality operation would look something like this:

     >>> class Matcher:
     ...     def __init__(self, compare, some_obj):
     ...         self.compare = compare
     ...         self.some_obj = some_obj
     ...     def __eq__(self, other):
     ...         return self.compare(self.some_obj, other)
     ...

Putting all this together:

     >>> match_foo = Matcher(compare, Foo(1, 2))
     >>> mock.assert_called_with(match_foo)

The ‘Matcher’ is instantiated with our compare function and the ‘Foo’
object we want to compare against.  In ‘assert_called_with’ the
‘Matcher’ equality method will be called, which compares the object the
mock was called with against the one we created our matcher with.  If
they match then ‘assert_called_with’ passes, and if they don’t an *note
AssertionError: 6ac. is raised:

     >>> match_wrong = Matcher(compare, Foo(3, 4))
     >>> mock.assert_called_with(match_wrong)
     Traceback (most recent call last):
         ...
     AssertionError: Expected: ((<Matcher object at 0x...>,), {})
     Called with: ((<Foo object at 0x...>,), {})

With a bit of tweaking you could have the comparison function raise the
*note AssertionError: 6ac. directly and provide a more useful failure
message.

As of version 1.5, the Python testing library PyHamcrest(1) provides
similar functionality, that may be useful here, in the form of its
equality matcher (hamcrest.library.integration.match_equality(2)).

   ---------- Footnotes ----------

   (1) https://pyhamcrest.readthedocs.io/

   (2) 
https://pyhamcrest.readthedocs.io/en/release-1.8/integration/#module-hamcrest.library.integration.match_equality


File: python.info,  Node: test — Regression tests package for Python,  Next: test support — Utilities for the Python test suite,  Prev: unittest mock — getting started,  Up: Development Tools

5.26.8 ‘test’ — Regression tests package for Python
---------------------------------------------------

     Note: The ‘test’ package is meant for internal use by Python only.
     It is documented for the benefit of the core developers of Python.
     Any use of this package outside of Python’s standard library is
     discouraged as code mentioned here can change or be removed without
     notice between releases of Python.

__________________________________________________________________

The ‘test’ package contains all regression tests for Python as well as
the modules *note test.support: e4. and *note test.regrtest: e3.
‘test.support’ is used to enhance your tests while ‘test.regrtest’
drives the testing suite.

Each module in the ‘test’ package whose name starts with ‘test_’ is a
testing suite for a specific module or feature.  All new tests should be
written using the *note unittest: 106. or *note doctest: 3a. module.
Some older tests are written using a “traditional” testing style that
compares output printed to ‘sys.stdout’; this style of test is
considered deprecated.

See also
........

Module *note unittest: 106.

     Writing PyUnit regression tests.

Module *note doctest: 3a.

     Tests embedded in documentation strings.

* Menu:

* Writing Unit Tests for the test package::
* Running tests using the command-line interface::


File: python.info,  Node: Writing Unit Tests for the test package,  Next: Running tests using the command-line interface,  Up: test — Regression tests package for Python

5.26.8.1 Writing Unit Tests for the ‘test’ package
..................................................

It is preferred that tests that use the *note unittest: 106. module
follow a few guidelines.  One is to name the test module by starting it
with ‘test_’ and end it with the name of the module being tested.  The
test methods in the test module should start with ‘test_’ and end with a
description of what the method is testing.  This is needed so that the
methods are recognized by the test driver as test methods.  Also, no
documentation string for the method should be included.  A comment (such
as ‘# Tests function returns only True or False’) should be used to
provide documentation for test methods.  This is done because
documentation strings get printed out if they exist and thus what test
is being run is not stated.

A basic boilerplate is often used:

     import unittest
     from test import support

     class MyTestCase1(unittest.TestCase):

         # Only use setUp() and tearDown() if necessary

         def setUp(self):
             ... code to execute in preparation for tests ...

         def tearDown(self):
             ... code to execute to clean up after tests ...

         def test_feature_one(self):
             # Test feature one.
             ... testing code ...

         def test_feature_two(self):
             # Test feature two.
             ... testing code ...

         ... more test methods ...

     class MyTestCase2(unittest.TestCase):
         ... same structure as MyTestCase1 ...

     ... more test classes ...

     if __name__ == '__main__':
         unittest.main()

This code pattern allows the testing suite to be run by *note
test.regrtest: e3, on its own as a script that supports the *note
unittest: 106. CLI, or via the ‘python -m unittest’ CLI.

The goal for regression testing is to try to break code.  This leads to
a few guidelines to be followed:

   * The testing suite should exercise all classes, functions, and
     constants.  This includes not just the external API that is to be
     presented to the outside world but also “private” code.

   * Whitebox testing (examining the code being tested when the tests
     are being written) is preferred.  Blackbox testing (testing only
     the published user interface) is not complete enough to make sure
     all boundary and edge cases are tested.

   * Make sure all possible values are tested including invalid ones.
     This makes sure that not only all valid values are acceptable but
     also that improper values are handled correctly.

   * Exhaust as many code paths as possible.  Test where branching
     occurs and thus tailor input to make sure as many different paths
     through the code are taken.

   * Add an explicit test for any bugs discovered for the tested code.
     This will make sure that the error does not crop up again if the
     code is changed in the future.

   * Make sure to clean up after your tests (such as close and remove
     all temporary files).

   * If a test is dependent on a specific condition of the operating
     system then verify the condition already exists before attempting
     the test.

   * Import as few modules as possible and do it as soon as possible.
     This minimizes external dependencies of tests and also minimizes
     possible anomalous behavior from side-effects of importing a
     module.

   * Try to maximize code reuse.  On occasion, tests will vary by
     something as small as what type of input is used.  Minimize code
     duplication by subclassing a basic test class with a class that
     specifies the input:

          class TestFuncAcceptsSequencesMixin:

              func = mySuperWhammyFunction

              def test_func(self):
                  self.func(self.arg)

          class AcceptLists(TestFuncAcceptsSequencesMixin, unittest.TestCase):
              arg = [1, 2, 3]

          class AcceptStrings(TestFuncAcceptsSequencesMixin, unittest.TestCase):
              arg = 'abc'

          class AcceptTuples(TestFuncAcceptsSequencesMixin, unittest.TestCase):
              arg = (1, 2, 3)

     When using this pattern, remember that all classes that inherit
     from *note unittest.TestCase: 451. are run as tests.  The
     ‘TestFuncAcceptsSequencesMixin’ class in the example above does not
     have any data and so can’t be run by itself, thus it does not
     inherit from ‘unittest.TestCase’.

See also
........

Test Driven Development

     A book by Kent Beck on writing tests before code.


File: python.info,  Node: Running tests using the command-line interface,  Prev: Writing Unit Tests for the test package,  Up: test — Regression tests package for Python

5.26.8.2 Running tests using the command-line interface
.......................................................

The ‘test’ package can be run as a script to drive Python’s regression
test suite, thanks to the *note -m: 5e4. option: ‘python -m test’.
Under the hood, it uses ‘test.regrtest’; the call ‘python -m
test.regrtest’ used in previous Python versions still works.  Running
the script by itself automatically starts running all regression tests
in the ‘test’ package.  It does this by finding all modules in the
package whose name starts with ‘test_’, importing them, and executing
the function ‘test_main()’ if present or loading the tests via
unittest.TestLoader.loadTestsFromModule if ‘test_main’ does not exist.
The names of tests to execute may also be passed to the script.
Specifying a single regression test (‘python -m test test_spam’) will
minimize output and only print whether the test passed or failed.

Running ‘test’ directly allows what resources are available for tests to
use to be set.  You do this by using the ‘-u’ command-line option.
Specifying ‘all’ as the value for the ‘-u’ option enables all possible
resources: ‘python -m test -uall’.  If all but one resource is desired
(a more common case), a comma-separated list of resources that are not
desired may be listed after ‘all’.  The command ‘python -m test
-uall,-audio,-largefile’ will run ‘test’ with all resources except the
‘audio’ and ‘largefile’ resources.  For a list of all resources and more
command-line options, run ‘python -m test -h’.

Some other ways to execute the regression tests depend on what platform
the tests are being executed on.  On Unix, you can run ‘make test’ at
the top-level directory where Python was built.  On Windows, executing
‘rt.bat’ from your ‘PCbuild’ directory will run all regression tests.


File: python.info,  Node: test support — Utilities for the Python test suite,  Next: test support socket_helper — Utilities for socket tests,  Prev: test — Regression tests package for Python,  Up: Development Tools

5.26.9 ‘test.support’ — Utilities for the Python test suite
-----------------------------------------------------------

The ‘test.support’ module provides support for Python’s regression test
suite.

     Note: ‘test.support’ is not a public module.  It is documented here
     to help Python developers write tests.  The API of this module is
     subject to change without backwards compatibility concerns between
     releases.

This module defines the following exceptions:

 -- Exception: test.support.TestFailed

     Exception to be raised when a test fails.  This is deprecated in
     favor of *note unittest: 106.-based tests and *note
     unittest.TestCase: 451.’s assertion methods.

 -- Exception: test.support.ResourceDenied

     Subclass of *note unittest.SkipTest: 101f.  Raised when a resource
     (such as a network connection) is not available.  Raised by the
     *note requires(): 4372. function.

The ‘test.support’ module defines the following constants:

 -- Data: test.support.verbose

     ‘True’ when verbose output is enabled.  Should be checked when more
     detailed information is desired about a running test.  'verbose' is
     set by *note test.regrtest: e3.

 -- Data: test.support.is_jython

     ‘True’ if the running interpreter is Jython.

 -- Data: test.support.is_android

     ‘True’ if the system is Android.

 -- Data: test.support.unix_shell

     Path for shell if not on Windows; otherwise ‘None’.

 -- Data: test.support.LOOPBACK_TIMEOUT

     Timeout in seconds for tests using a network server listening on
     the network local loopback interface like ‘127.0.0.1’.

     The timeout is long enough to prevent test failure: it takes into
     account that the client and the server can run in different threads
     or even different processes.

     The timeout should be long enough for *note connect(): dd1, *note
     recv(): dd2. and *note send(): dd5. methods of *note socket.socket:
     dcf.

     Its default value is 5 seconds.

     See also *note INTERNET_TIMEOUT: 1b45.

 -- Data: test.support.INTERNET_TIMEOUT

     Timeout in seconds for network requests going to the internet.

     The timeout is short enough to prevent a test to wait for too long
     if the internet request is blocked for whatever reason.

     Usually, a timeout using ‘INTERNET_TIMEOUT’ should not mark a test
     as failed, but skip the test instead: see *note
     transient_internet(): 4377.

     Its default value is 1 minute.

     See also *note LOOPBACK_TIMEOUT: 1b44.

 -- Data: test.support.SHORT_TIMEOUT

     Timeout in seconds to mark a test as failed if the test takes “too
     long”.

     The timeout value depends on the regrtest ‘--timeout’ command line
     option.

     If a test using ‘SHORT_TIMEOUT’ starts to fail randomly on slow
     buildbots, use *note LONG_TIMEOUT: 1b46. instead.

     Its default value is 30 seconds.

 -- Data: test.support.LONG_TIMEOUT

     Timeout in seconds to detect when a test hangs.

     It is long enough to reduce the risk of test failure on the slowest
     Python buildbots.  It should not be used to mark a test as failed
     if the test takes “too long”.  The timeout value depends on the
     regrtest ‘--timeout’ command line option.

     Its default value is 5 minutes.

     See also *note LOOPBACK_TIMEOUT: 1b44, *note INTERNET_TIMEOUT:
     1b45. and *note SHORT_TIMEOUT: 1a09.

 -- Data: test.support.PGO

     Set when tests can be skipped when they are not useful for PGO.

 -- Data: test.support.PIPE_MAX_SIZE

     A constant that is likely larger than the underlying OS pipe buffer
     size, to make writes blocking.

 -- Data: test.support.Py_DEBUG

     ‘True’ if Python was built with the *note Py_DEBUG: 437b. macro
     defined, that is, if Python was *note built in debug mode: 1f9.

     Added in version 3.12.

 -- Data: test.support.SOCK_MAX_SIZE

     A constant that is likely larger than the underlying OS socket
     buffer size, to make writes blocking.

 -- Data: test.support.TEST_SUPPORT_DIR

     Set to the top level directory that contains ‘test.support’.

 -- Data: test.support.TEST_HOME_DIR

     Set to the top level directory for the test package.

 -- Data: test.support.TEST_DATA_DIR

     Set to the ‘data’ directory within the test package.

 -- Data: test.support.MAX_Py_ssize_t

     Set to *note sys.maxsize: 120a. for big memory tests.

 -- Data: test.support.max_memuse

     Set by *note set_memlimit(): 4382. as the memory limit for big
     memory tests.  Limited by *note MAX_Py_ssize_t: 4380.

 -- Data: test.support.real_max_memuse

     Set by *note set_memlimit(): 4382. as the memory limit for big
     memory tests.  Not limited by *note MAX_Py_ssize_t: 4380.

 -- Data: test.support.MISSING_C_DOCSTRINGS

     Set to ‘True’ if Python is built without docstrings (the
     ‘WITH_DOC_STRINGS’ macro is not defined).  See the *note configure
     -without-doc-strings: 1f56. option.

     See also the *note HAVE_DOCSTRINGS: 4385. variable.

 -- Data: test.support.HAVE_DOCSTRINGS

     Set to ‘True’ if function docstrings are available.  See the *note
     python -OO: de3. option, which strips docstrings of functions
     implemented in Python.

     See also the *note MISSING_C_DOCSTRINGS: 4384. variable.

 -- Data: test.support.TEST_HTTP_URL

     Define the URL of a dedicated HTTP server for the network tests.

 -- Data: test.support.ALWAYS_EQ

     Object that is equal to anything.  Used to test mixed type
     comparison.

 -- Data: test.support.NEVER_EQ

     Object that is not equal to anything (even to *note ALWAYS_EQ:
     4387.).  Used to test mixed type comparison.

 -- Data: test.support.LARGEST

     Object that is greater than anything (except itself).  Used to test
     mixed type comparison.

 -- Data: test.support.SMALLEST

     Object that is less than anything (except itself).  Used to test
     mixed type comparison.

The ‘test.support’ module defines the following functions:

 -- Function: test.support.busy_retry (timeout, err_msg=None, /, *,
          error=True)

     Run the loop body until ‘break’ stops the loop.

     After 'timeout' seconds, raise an *note AssertionError: 6ac. if
     'error' is true, or just stop the loop if 'error' is false.

     Example:

          for _ in support.busy_retry(support.SHORT_TIMEOUT):
              if check():
                  break

     Example of error=False usage:

          for _ in support.busy_retry(support.SHORT_TIMEOUT, error=False):
              if check():
                  break
          else:
              raise RuntimeError('my custom error')

 -- Function: test.support.sleeping_retry (timeout, err_msg=None, /, *,
          init_delay=0.010, max_delay=1.0, error=True)

     Wait strategy that applies exponential backoff.

     Run the loop body until ‘break’ stops the loop.  Sleep at each loop
     iteration, but not at the first iteration.  The sleep delay is
     doubled at each iteration (up to 'max_delay' seconds).

     See *note busy_retry(): 438b. documentation for the parameters
     usage.

     Example raising an exception after SHORT_TIMEOUT seconds:

          for _ in support.sleeping_retry(support.SHORT_TIMEOUT):
              if check():
                  break

     Example of error=False usage:

          for _ in support.sleeping_retry(support.SHORT_TIMEOUT, error=False):
              if check():
                  break
          else:
              raise RuntimeError('my custom error')

 -- Function: test.support.is_resource_enabled (resource)

     Return ‘True’ if 'resource' is enabled and available.  The list of
     available resources is only set when *note test.regrtest: e3. is
     executing the tests.

 -- Function: test.support.get_resource_value (resource)

     Return the value specified for 'resource' (as ‘-u RESOURCE=VALUE’).
     Return ‘None’ if 'resource' is disabled or no value is specified.

 -- Function: test.support.python_is_optimized ()

     Return ‘True’ if Python was not built with ‘-O0’ or ‘-Og’.

 -- Function: test.support.with_pymalloc ()

     Return ‘_testcapi.WITH_PYMALLOC’.

 -- Function: test.support.requires (resource, msg=None)

     Raise *note ResourceDenied: 4371. if 'resource' is not available.
     'msg' is the argument to ‘ResourceDenied’ if it is raised.  Always
     returns ‘True’ if called by a function whose ‘__name__’ is
     ‘'__main__'’.  Used when tests are executed by *note test.regrtest:
     e3.

 -- Function: test.support.sortdict (dict)

     Return a repr of 'dict' with keys sorted.

 -- Function: test.support.findfile (filename, subdir=None)

     Return the path to the file named 'filename'.  If no match is found
     'filename' is returned.  This does not equal a failure since it
     could be the path to the file.

     Setting 'subdir' indicates a relative path to use to find the file
     rather than looking directly in the path directories.

 -- Function: test.support.get_pagesize ()

     Get size of a page in bytes.

     Added in version 3.12.

 -- Function: test.support.setswitchinterval (interval)

     Set the *note sys.setswitchinterval(): 954. to the given
     'interval'.  Defines a minimum interval for Android systems to
     prevent the system from hanging.

 -- Function: test.support.check_impl_detail (**guards)

     Use this check to guard CPython’s implementation-specific tests or
     to run them only on the implementations guarded by the arguments.
     This function returns ‘True’ or ‘False’ depending on the host
     platform.  Example usage:

          check_impl_detail()               # Only on CPython (default).
          check_impl_detail(jython=True)    # Only on Jython.
          check_impl_detail(cpython=False)  # Everywhere except CPython.

 -- Function: test.support.set_memlimit (limit)

     Set the values for *note max_memuse: 4381. and *note
     real_max_memuse: 4383. for big memory tests.

 -- Function: test.support.record_original_stdout (stdout)

     Store the value from 'stdout'.  It is meant to hold the stdout at
     the time the regrtest began.

 -- Function: test.support.get_original_stdout ()

     Return the original stdout set by *note record_original_stdout():
     4396. or ‘sys.stdout’ if it’s not set.

 -- Function: test.support.args_from_interpreter_flags ()

     Return a list of command line arguments reproducing the current
     settings in ‘sys.flags’ and ‘sys.warnoptions’.

 -- Function: test.support.optim_args_from_interpreter_flags ()

     Return a list of command line arguments reproducing the current
     optimization settings in ‘sys.flags’.

 -- Function: test.support.captured_stdin ()
 -- Function: test.support.captured_stdout ()
 -- Function: test.support.captured_stderr ()

     A context managers that temporarily replaces the named stream with
     *note io.StringIO: f5e. object.

     Example use with output streams:

          with captured_stdout() as stdout, captured_stderr() as stderr:
              print("hello")
              print("error", file=sys.stderr)
          assert stdout.getvalue() == "hello\n"
          assert stderr.getvalue() == "error\n"

     Example use with input stream:

          with captured_stdin() as stdin:
              stdin.write('hello\n')
              stdin.seek(0)
              # call test code that consumes from sys.stdin
              captured = input()
          self.assertEqual(captured, "hello")

 -- Function: test.support.disable_faulthandler ()

     A context manager that temporary disables *note faulthandler: 58.

 -- Function: test.support.gc_collect ()

     Force as many objects as possible to be collected.  This is needed
     because timely deallocation is not guaranteed by the garbage
     collector.  This means that ‘__del__’ methods may be called later
     than expected and weakrefs may remain alive for longer than
     expected.

 -- Function: test.support.disable_gc ()

     A context manager that disables the garbage collector on entry.  On
     exit, the garbage collector is restored to its prior state.

 -- Function: test.support.swap_attr (obj, attr, new_val)

     Context manager to swap out an attribute with a new object.

     Usage:

          with swap_attr(obj, "attr", 5):
              ...

     This will set ‘obj.attr’ to 5 for the duration of the ‘with’ block,
     restoring the old value at the end of the block.  If ‘attr’ doesn’t
     exist on ‘obj’, it will be created and then deleted at the end of
     the block.

     The old value (or ‘None’ if it doesn’t exist) will be assigned to
     the target of the “as” clause, if there is one.

 -- Function: test.support.swap_item (obj, attr, new_val)

     Context manager to swap out an item with a new object.

     Usage:

          with swap_item(obj, "item", 5):
              ...

     This will set ‘obj["item"]’ to 5 for the duration of the ‘with’
     block, restoring the old value at the end of the block.  If ‘item’
     doesn’t exist on ‘obj’, it will be created and then deleted at the
     end of the block.

     The old value (or ‘None’ if it doesn’t exist) will be assigned to
     the target of the “as” clause, if there is one.

 -- Function: test.support.flush_std_streams ()

     Call the ‘flush()’ method on *note sys.stdout: aec. and then on
     *note sys.stderr: 943.  It can be used to make sure that the logs
     order is consistent before writing into stderr.

     Added in version 3.11.

 -- Function: test.support.print_warning (msg)

     Print a warning into *note sys.__stderr__: 43a3.  Format the
     message as: ‘f"Warning -- {msg}"’.  If 'msg' is made of multiple
     lines, add ‘"Warning -- "’ prefix to each line.

     Added in version 3.9.

 -- Function: test.support.wait_process (pid, *, exitcode, timeout=None)

     Wait until process 'pid' completes and check that the process exit
     code is 'exitcode'.

     Raise an *note AssertionError: 6ac. if the process exit code is not
     equal to 'exitcode'.

     If the process runs longer than 'timeout' seconds (*note
     SHORT_TIMEOUT: 1a09. by default), kill the process and raise an
     *note AssertionError: 6ac.  The timeout feature is not available on
     Windows.

     Added in version 3.9.

 -- Function: test.support.calcobjsize (fmt)

     Return the size of the *note PyObject: 33a. whose structure members
     are defined by 'fmt'.  The returned value includes the size of the
     Python object header and alignment.

 -- Function: test.support.calcvobjsize (fmt)

     Return the size of the *note PyVarObject: 43a6. whose structure
     members are defined by 'fmt'.  The returned value includes the size
     of the Python object header and alignment.

 -- Function: test.support.checksizeof (test, o, size)

     For testcase 'test', assert that the ‘sys.getsizeof’ for 'o' plus
     the GC header size equals 'size'.

 -- Function: @test.support.anticipate_failure (condition)

     A decorator to conditionally mark tests with *note
     unittest.expectedFailure(): 42bc.  Any use of this decorator should
     have an associated comment identifying the relevant tracker issue.

 -- Function: test.support.system_must_validate_cert (f)

     A decorator that skips the decorated test on TLS certification
     validation failures.

 -- Function: @test.support.run_with_locale (catstr, *locales)

     A decorator for running a function in a different locale, correctly
     resetting it after it has finished.  'catstr' is the locale
     category as a string (for example ‘"LC_ALL"’).  The 'locales'
     passed will be tried sequentially, and the first valid locale will
     be used.

 -- Function: @test.support.run_with_tz (tz)

     A decorator for running a function in a specific timezone,
     correctly resetting it after it has finished.

 -- Function: @test.support.requires_freebsd_version (*min_version)

     Decorator for the minimum version when running test on FreeBSD. If
     the FreeBSD version is less than the minimum, the test is skipped.

 -- Function: @test.support.requires_linux_version (*min_version)

     Decorator for the minimum version when running test on Linux.  If
     the Linux version is less than the minimum, the test is skipped.

 -- Function: @test.support.requires_mac_version (*min_version)

     Decorator for the minimum version when running test on macOS. If
     the macOS version is less than the minimum, the test is skipped.

 -- Function: @test.support.requires_gil_enabled

     Decorator for skipping tests on the free-threaded build.  If the
     *note GIL: 159. is disabled, the test is skipped.

 -- Function: @test.support.requires_IEEE_754

     Decorator for skipping tests on non-IEEE 754 platforms.

 -- Function: @test.support.requires_zlib

     Decorator for skipping tests if *note zlib: 133. doesn’t exist.

 -- Function: @test.support.requires_gzip

     Decorator for skipping tests if *note gzip: 67. doesn’t exist.

 -- Function: @test.support.requires_bz2

     Decorator for skipping tests if *note bz2: 13. doesn’t exist.

 -- Function: @test.support.requires_lzma

     Decorator for skipping tests if *note lzma: 8a. doesn’t exist.

 -- Function: @test.support.requires_resource (resource)

     Decorator for skipping tests if 'resource' is not available.

 -- Function: @test.support.requires_docstrings

     Decorator for only running the test if *note HAVE_DOCSTRINGS: 4385.

 -- Function: @test.support.requires_limited_api

     Decorator for only running the test if *note Limited C API: 399. is
     available.

 -- Function: @test.support.cpython_only

     Decorator for tests only applicable to CPython.

 -- Function: @test.support.impl_detail (msg=None, **guards)

     Decorator for invoking *note check_impl_detail(): 4395. on
     'guards'.  If that returns ‘False’, then uses 'msg' as the reason
     for skipping the test.

 -- Function: @test.support.no_tracing

     Decorator to temporarily turn off tracing for the duration of the
     test.

 -- Function: @test.support.refcount_test

     Decorator for tests which involve reference counting.  The
     decorator does not run the test if it is not run by CPython.  Any
     trace function is unset for the duration of the test to prevent
     unexpected refcounts caused by the trace function.

 -- Function: @test.support.bigmemtest (size, memuse, dry_run=True)

     Decorator for bigmem tests.

     'size' is a requested size for the test (in arbitrary,
     test-interpreted units.)  'memuse' is the number of bytes per unit
     for the test, or a good estimate of it.  For example, a test that
     needs two byte buffers, of 4 GiB each, could be decorated with
     ‘@bigmemtest(size=_4G, memuse=2)’.

     The 'size' argument is normally passed to the decorated test method
     as an extra argument.  If 'dry_run' is ‘True’, the value passed to
     the test method may be less than the requested value.  If 'dry_run'
     is ‘False’, it means the test doesn’t support dummy runs when ‘-M’
     is not specified.

 -- Function: @test.support.bigaddrspacetest

     Decorator for tests that fill the address space.

 -- Function: test.support.check_syntax_error (testcase, statement,
          errtext='', *, lineno=None, offset=None)

     Test for syntax errors in 'statement' by attempting to compile
     'statement'.  'testcase' is the *note unittest: 106. instance for
     the test.  'errtext' is the regular expression which should match
     the string representation of the raised *note SyntaxError: 18d.  If
     'lineno' is not ‘None’, compares to the line of the exception.  If
     'offset' is not ‘None’, compares to the offset of the exception.

 -- Function: test.support.open_urlresource (url, *args, **kw)

     Open 'url'.  If open fails, raises *note TestFailed: 4370.

 -- Function: test.support.reap_children ()

     Use this at the end of ‘test_main’ whenever sub-processes are
     started.  This will help ensure that no extra children (zombies)
     stick around to hog resources and create problems when looking for
     refleaks.

 -- Function: test.support.get_attribute (obj, name)

     Get an attribute, raising *note unittest.SkipTest: 101f. if *note
     AttributeError: 34e. is raised.

 -- Function: test.support.catch_unraisable_exception ()

     Context manager catching unraisable exception using *note
     sys.unraisablehook(): 1f7.

     Storing the exception value (‘cm.unraisable.exc_value’) creates a
     reference cycle.  The reference cycle is broken explicitly when the
     context manager exits.

     Storing the object (‘cm.unraisable.object’) can resurrect it if it
     is set to an object which is being finalized.  Exiting the context
     manager clears the stored object.

     Usage:

          with support.catch_unraisable_exception() as cm:
              # code creating an "unraisable exception"
              ...

              # check the unraisable exception: use cm.unraisable
              ...

          # cm.unraisable attribute no longer exists at this point
          # (to break a reference cycle)

     Added in version 3.8.

 -- Function: test.support.load_package_tests (pkg_dir, loader,
          standard_tests, pattern)

     Generic implementation of the *note unittest: 106. ‘load_tests’
     protocol for use in test packages.  'pkg_dir' is the root directory
     of the package; 'loader', 'standard_tests', and 'pattern' are the
     arguments expected by ‘load_tests’.  In simple cases, the test
     package’s ‘__init__.py’ can be the following:

          import os
          from test.support import load_package_tests

          def load_tests(*args):
              return load_package_tests(os.path.dirname(__file__), *args)

 -- Function: test.support.detect_api_mismatch (ref_api, other_api, *,
          ignore=())

     Returns the set of attributes, functions or methods of 'ref_api'
     not found on 'other_api', except for a defined list of items to be
     ignored in this check specified in 'ignore'.

     By default this skips private attributes beginning with ‘_’ but
     includes all magic methods, i.e.  those starting and ending in
     ‘__’.

     Added in version 3.5.

 -- Function: test.support.patch (test_instance, object_to_patch,
          attr_name, new_value)

     Override 'object_to_patch.attr_name' with 'new_value'.  Also add
     cleanup procedure to 'test_instance' to restore 'object_to_patch'
     for 'attr_name'.  The 'attr_name' should be a valid attribute for
     'object_to_patch'.

 -- Function: test.support.run_in_subinterp (code)

     Run 'code' in subinterpreter.  Raise *note unittest.SkipTest: 101f.
     if *note tracemalloc: ff. is enabled.

 -- Function: test.support.check_free_after_iterating (test, iter, cls,
          args=())

     Assert instances of 'cls' are deallocated after iterating.

 -- Function: test.support.missing_compiler_executable (cmd_names=[])

     Check for the existence of the compiler executables whose names are
     listed in 'cmd_names' or all the compiler executables when
     'cmd_names' is empty and return the first missing executable or
     ‘None’ when none is found missing.

 -- Function: test.support.check__all__ (test_case, module,
          name_of_module=None, extra=(), not_exported=())

     Assert that the ‘__all__’ variable of 'module' contains all public
     names.

     The module’s public names (its API) are detected automatically
     based on whether they match the public name convention and were
     defined in 'module'.

     The 'name_of_module' argument can specify (as a string or tuple
     thereof) what module(s) an API could be defined in order to be
     detected as a public API. One case for this is when 'module'
     imports part of its public API from other modules, possibly a C
     backend (like ‘csv’ and its ‘_csv’).

     The 'extra' argument can be a set of names that wouldn’t otherwise
     be automatically detected as “public”, like objects without a
     proper *note __module__: 242f. attribute.  If provided, it will be
     added to the automatically detected ones.

     The 'not_exported' argument can be a set of names that must not be
     treated as part of the public API even though their names indicate
     otherwise.

     Example use:

          import bar
          import foo
          import unittest
          from test import support

          class MiscTestCase(unittest.TestCase):
              def test__all__(self):
                  support.check__all__(self, foo)

          class OtherTestCase(unittest.TestCase):
              def test__all__(self):
                  extra = {'BAR_CONST', 'FOO_CONST'}
                  not_exported = {'baz'}  # Undocumented name.
                  # bar imports part of its API from _bar.
                  support.check__all__(self, bar, ('bar', '_bar'),
                                       extra=extra, not_exported=not_exported)

     Added in version 3.6.

 -- Function: test.support.skip_if_broken_multiprocessing_synchronize ()

     Skip tests if the ‘multiprocessing.synchronize’ module is missing,
     if there is no available semaphore implementation, or if creating a
     lock raises an *note OSError: 41a.

     Added in version 3.10.

 -- Function: test.support.check_disallow_instantiation (test_case, tp,
          *args, **kwds)

     Assert that type 'tp' cannot be instantiated using 'args' and
     'kwds'.

     Added in version 3.10.

 -- Function: test.support.adjust_int_max_str_digits (max_digits)

     This function returns a context manager that will change the global
     *note sys.set_int_max_str_digits(): 18e0. setting for the duration
     of the context to allow execution of test code that needs a
     different limit on the number of digits when converting between an
     integer and string.

     Added in version 3.11.

The ‘test.support’ module defines the following classes:

 -- Class: test.support.SuppressCrashReport

     A context manager used to try to prevent crash dialog popups on
     tests that are expected to crash a subprocess.

     On Windows, it disables Windows Error Reporting dialogs using
     SetErrorMode(1).

     On UNIX, *note resource.setrlimit(): 1625. is used to set *note
     resource.RLIMIT_CORE: 43cb.’s soft limit to 0 to prevent coredump
     file creation.

     On both platforms, the old value is restored by *note __exit__():
     1349.

 -- Class: test.support.SaveSignals

     Class to save and restore signal handlers registered by the Python
     signal handler.

      -- Method: save (self)

          Save the signal handlers to a dictionary mapping signal
          numbers to the current signal handler.

      -- Method: restore (self)

          Set the signal numbers from the *note save(): 43cd. dictionary
          to the saved handler.

 -- Class: test.support.Matcher

      -- Method: matches (self, d, **kwargs)

          Try to match a single dict with the supplied arguments.

      -- Method: match_value (self, k, dv, v)

          Try to match a single stored value ('dv') with a supplied
          value ('v').

   ---------- Footnotes ----------

   (1) 
https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx


File: python.info,  Node: test support socket_helper — Utilities for socket tests,  Next: test support script_helper — Utilities for the Python execution tests,  Prev: test support — Utilities for the Python test suite,  Up: Development Tools

5.26.10 ‘test.support.socket_helper’ — Utilities for socket tests
-----------------------------------------------------------------

The ‘test.support.socket_helper’ module provides support for socket
tests.

Added in version 3.9.

 -- Data: test.support.socket_helper.IPV6_ENABLED

     Set to ‘True’ if IPv6 is enabled on this host, ‘False’ otherwise.

 -- Function: test.support.socket_helper.find_unused_port
          (family=socket.AF_INET, socktype=socket.SOCK_STREAM)

     Returns an unused port that should be suitable for binding.  This
     is achieved by creating a temporary socket with the same family and
     type as the ‘sock’ parameter (default is *note AF_INET: 1953, *note
     SOCK_STREAM: 133c.), and binding it to the specified host address
     (defaults to ‘0.0.0.0’) with the port set to 0, eliciting an unused
     ephemeral port from the OS. The temporary socket is then closed and
     deleted, and the ephemeral port is returned.

     Either this method or *note bind_port(): 43d5. should be used for
     any tests where a server socket needs to be bound to a particular
     port for the duration of the test.  Which one to use depends on
     whether the calling code is creating a Python socket, or if an
     unused port needs to be provided in a constructor or passed to an
     external program (i.e.  the ‘-accept’ argument to openssl’s
     s_server mode).  Always prefer ‘bind_port()’ over
     ‘find_unused_port()’ where possible.  Using a hard coded port is
     discouraged since it can make multiple instances of the test
     impossible to run simultaneously, which is a problem for buildbots.

 -- Function: test.support.socket_helper.bind_port (sock, host=HOST)

     Bind the socket to a free port and return the port number.  Relies
     on ephemeral ports in order to ensure we are using an unbound port.
     This is important as many tests may be running simultaneously,
     especially in a buildbot environment.  This method raises an
     exception if the ‘sock.family’ is *note AF_INET: 1953. and
     ‘sock.type’ is *note SOCK_STREAM: 133c, and the socket has
     ‘SO_REUSEADDR’ or ‘SO_REUSEPORT’ set on it.  Tests should never set
     these socket options for TCP/IP sockets.  The only case for setting
     these options is testing multicasting via multiple UDP sockets.

     Additionally, if the ‘SO_EXCLUSIVEADDRUSE’ socket option is
     available (i.e.  on Windows), it will be set on the socket.  This
     will prevent anyone else from binding to our host/port for the
     duration of the test.

 -- Function: test.support.socket_helper.bind_unix_socket (sock, addr)

     Bind a Unix socket, raising *note unittest.SkipTest: 101f. if *note
     PermissionError: d6b. is raised.

 -- Function: @test.support.socket_helper.skip_unless_bind_unix_socket

     A decorator for running tests that require a functional ‘bind()’
     for Unix sockets.

 -- Function: test.support.socket_helper.transient_internet
          (resource_name, *, timeout=30.0, errnos=())

     A context manager that raises *note ResourceDenied: 4371. when
     various issues with the internet connection manifest themselves as
     exceptions.


File: python.info,  Node: test support script_helper — Utilities for the Python execution tests,  Next: test support bytecode_helper — Support tools for testing correct bytecode generation,  Prev: test support socket_helper — Utilities for socket tests,  Up: Development Tools

5.26.11 ‘test.support.script_helper’ — Utilities for the Python execution tests
-------------------------------------------------------------------------------

The ‘test.support.script_helper’ module provides support for Python’s
script execution tests.

 -- Function:
          test.support.script_helper.interpreter_requires_environment ()

     Return ‘True’ if ‘sys.executable interpreter’ requires environment
     variables in order to be able to run at all.

     This is designed to be used with ‘@unittest.skipIf()’ to annotate
     tests that need to use an ‘assert_python*()’ function to launch an
     isolated mode (‘-I’) or no environment mode (‘-E’) sub-interpreter
     process.

     A normal build & test does not run into this situation but it can
     happen when trying to run the standard library test suite from an
     interpreter that doesn’t have an obvious home with Python’s current
     home finding logic.

     Setting *note PYTHONHOME: 3bf. is one way to get most of the
     testsuite to run in that situation.  *note PYTHONPATH: 1058. or
     ‘PYTHONUSERSITE’ are other common environment variables that might
     impact whether or not the interpreter can start.

 -- Function: test.support.script_helper.run_python_until_end (*args,
          **env_vars)

     Set up the environment based on 'env_vars' for running the
     interpreter in a subprocess.  The values can include ‘__isolated’,
     ‘__cleanenv’, ‘__cwd’, and ‘TERM’.

     Changed in version 3.9: The function no longer strips whitespaces
     from 'stderr'.

 -- Function: test.support.script_helper.assert_python_ok (*args,
          **env_vars)

     Assert that running the interpreter with 'args' and optional
     environment variables 'env_vars' succeeds (‘rc == 0’) and return a
     ‘(return code, stdout, stderr)’ tuple.

     If the '__cleanenv' keyword-only parameter is set, 'env_vars' is
     used as a fresh environment.

     Python is started in isolated mode (command line option ‘-I’),
     except if the '__isolated' keyword-only parameter is set to
     ‘False’.

     Changed in version 3.9: The function no longer strips whitespaces
     from 'stderr'.

 -- Function: test.support.script_helper.assert_python_failure (*args,
          **env_vars)

     Assert that running the interpreter with 'args' and optional
     environment variables 'env_vars' fails (‘rc != 0’) and return a
     ‘(return code, stdout, stderr)’ tuple.

     See *note assert_python_ok(): 43db. for more options.

     Changed in version 3.9: The function no longer strips whitespaces
     from 'stderr'.

 -- Function: test.support.script_helper.spawn_python (*args,
          stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kw)

     Run a Python subprocess with the given arguments.

     'kw' is extra keyword args to pass to *note subprocess.Popen():
     199.  Returns a *note subprocess.Popen: 199. object.

 -- Function: test.support.script_helper.kill_python (p)

     Run the given *note subprocess.Popen: 199. process until completion
     and return stdout.

 -- Function: test.support.script_helper.make_script (script_dir,
          script_basename, source, omit_suffix=False)

     Create script containing 'source' in path 'script_dir' and
     'script_basename'.  If 'omit_suffix' is ‘False’, append ‘.py’ to
     the name.  Return the full script path.

 -- Function: test.support.script_helper.make_zip_script (zip_dir,
          zip_basename, script_name, name_in_zip=None)

     Create zip file at 'zip_dir' and 'zip_basename' with extension
     ‘zip’ which contains the files in 'script_name'.  'name_in_zip' is
     the archive name.  Return a tuple containing ‘(full path, full path
     of archive name)’.

 -- Function: test.support.script_helper.make_pkg (pkg_dir,
          init_source='')

     Create a directory named 'pkg_dir' containing an ‘__init__’ file
     with 'init_source' as its contents.

 -- Function: test.support.script_helper.make_zip_pkg (zip_dir,
          zip_basename, pkg_name, script_basename, source, depth=1,
          compiled=False)

     Create a zip package directory with a path of 'zip_dir' and
     'zip_basename' containing an empty ‘__init__’ file and a file
     'script_basename' containing the 'source'.  If 'compiled' is
     ‘True’, both source files will be compiled and added to the zip
     package.  Return a tuple of the full zip path and the archive name
     for the zip file.


File: python.info,  Node: test support bytecode_helper — Support tools for testing correct bytecode generation,  Next: test support threading_helper — Utilities for threading tests,  Prev: test support script_helper — Utilities for the Python execution tests,  Up: Development Tools

5.26.12 ‘test.support.bytecode_helper’ — Support tools for testing correct bytecode generation
----------------------------------------------------------------------------------------------

The ‘test.support.bytecode_helper’ module provides support for testing
and inspecting bytecode generation.

Added in version 3.9.

The module defines the following class:

 -- Class: test.support.bytecode_helper.BytecodeTestCase
          (unittest.TestCase)

     This class has custom assertion methods for inspecting bytecode.

 -- Method: BytecodeTestCase.get_disassembly_as_string (co)

     Return the disassembly of 'co' as string.

 -- Method: BytecodeTestCase.assertInBytecode (x, opname,
          argval=_UNSPECIFIED)

     Return instr if 'opname' is found, otherwise throws *note
     AssertionError: 6ac.

 -- Method: BytecodeTestCase.assertNotInBytecode (x, opname,
          argval=_UNSPECIFIED)

     Throws *note AssertionError: 6ac. if 'opname' is found.


File: python.info,  Node: test support threading_helper — Utilities for threading tests,  Next: test support os_helper — Utilities for os tests,  Prev: test support bytecode_helper — Support tools for testing correct bytecode generation,  Up: Development Tools

5.26.13 ‘test.support.threading_helper’ — Utilities for threading tests
-----------------------------------------------------------------------

The ‘test.support.threading_helper’ module provides support for
threading tests.

Added in version 3.10.

 -- Function: test.support.threading_helper.join_thread (thread,
          timeout=None)

     Join a 'thread' within 'timeout'.  Raise an *note AssertionError:
     6ac. if thread is still alive after 'timeout' seconds.

 -- Function: @test.support.threading_helper.reap_threads

     Decorator to ensure the threads are cleaned up even if the test
     fails.

 -- Function: test.support.threading_helper.start_threads (threads,
          unlock=None)

     Context manager to start 'threads', which is a sequence of threads.
     'unlock' is a function called after the threads are started, even
     if an exception was raised; an example would be *note
     threading.Event.set(): 332e.  ‘start_threads’ will attempt to join
     the started threads upon exit.

 -- Function: test.support.threading_helper.threading_cleanup
          (*original_values)

     Cleanup up threads not specified in 'original_values'.  Designed to
     emit a warning if a test leaves running threads in the background.

 -- Function: test.support.threading_helper.threading_setup ()

     Return current thread count and copy of dangling threads.

 -- Function: test.support.threading_helper.wait_threads_exit
          (timeout=None)

     Context manager to wait until all threads created in the ‘with’
     statement exit.

 -- Function: test.support.threading_helper.catch_threading_exception ()

     Context manager catching *note threading.Thread: 956. exception
     using *note threading.excepthook(): 851.

     Attributes set when an exception is caught:

        * ‘exc_type’

        * ‘exc_value’

        * ‘exc_traceback’

        * ‘thread’

     See *note threading.excepthook(): 851. documentation.

     These attributes are deleted at the context manager exit.

     Usage:

          with threading_helper.catch_threading_exception() as cm:
              # code spawning a thread which raises an exception
              ...

              # check the thread exception, use cm attributes:
              # exc_type, exc_value, exc_traceback, thread
              ...

          # exc_type, exc_value, exc_traceback, thread attributes of cm no longer
          # exists at this point
          # (to avoid reference cycles)

     Added in version 3.8.


File: python.info,  Node: test support os_helper — Utilities for os tests,  Next: test support import_helper — Utilities for import tests,  Prev: test support threading_helper — Utilities for threading tests,  Up: Development Tools

5.26.14 ‘test.support.os_helper’ — Utilities for os tests
---------------------------------------------------------

The ‘test.support.os_helper’ module provides support for os tests.

Added in version 3.10.

 -- Data: test.support.os_helper.FS_NONASCII

     A non-ASCII character encodable by *note os.fsencode(): c76.

 -- Data: test.support.os_helper.SAVEDCWD

     Set to *note os.getcwd(): 16a1.

 -- Data: test.support.os_helper.TESTFN

     Set to a name that is safe to use as the name of a temporary file.
     Any temporary file that is created should be closed and unlinked
     (removed).

 -- Data: test.support.os_helper.TESTFN_NONASCII

     Set to a filename containing the *note FS_NONASCII: 43f1.
     character, if it exists.  This guarantees that if the filename
     exists, it can be encoded and decoded with the default filesystem
     encoding.  This allows tests that require a non-ASCII filename to
     be easily skipped on platforms where they can’t work.

 -- Data: test.support.os_helper.TESTFN_UNENCODABLE

     Set to a filename (str type) that should not be able to be encoded
     by file system encoding in strict mode.  It may be ‘None’ if it’s
     not possible to generate such a filename.

 -- Data: test.support.os_helper.TESTFN_UNDECODABLE

     Set to a filename (bytes type) that should not be able to be
     decoded by file system encoding in strict mode.  It may be ‘None’
     if it’s not possible to generate such a filename.

 -- Data: test.support.os_helper.TESTFN_UNICODE

     Set to a non-ASCII name for a temporary file.

 -- Class: test.support.os_helper.EnvironmentVarGuard

     Class used to temporarily set or unset environment variables.
     Instances can be used as a context manager and have a complete
     dictionary interface for querying/modifying the underlying
     ‘os.environ’.  After exit from the context manager all changes to
     environment variables done through this instance will be rolled
     back.

     Changed in version 3.1: Added dictionary interface.

 -- Class: test.support.os_helper.FakePath (path)

     Simple *note path-like object: 2a0.  It implements the *note
     __fspath__(): c73. method which just returns the 'path' argument.
     If 'path' is an exception, it will be raised in ‘__fspath__()’.

 -- Method: EnvironmentVarGuard.set (envvar, value)

     Temporarily set the environment variable ‘envvar’ to the value of
     ‘value’.

 -- Method: EnvironmentVarGuard.unset (envvar)

     Temporarily unset the environment variable ‘envvar’.

 -- Function: test.support.os_helper.can_symlink ()

     Return ‘True’ if the OS supports symbolic links, ‘False’ otherwise.

 -- Function: test.support.os_helper.can_xattr ()

     Return ‘True’ if the OS supports xattr, ‘False’ otherwise.

 -- Function: test.support.os_helper.change_cwd (path, quiet=False)

     A context manager that temporarily changes the current working
     directory to 'path' and yields the directory.

     If 'quiet' is ‘False’, the context manager raises an exception on
     error.  Otherwise, it issues only a warning and keeps the current
     working directory the same.

 -- Function: test.support.os_helper.create_empty_file (filename)

     Create an empty file with 'filename'.  If it already exists,
     truncate it.

 -- Function: test.support.os_helper.fd_count ()

     Count the number of open file descriptors.

 -- Function: test.support.os_helper.fs_is_case_insensitive (directory)

     Return ‘True’ if the file system for 'directory' is
     case-insensitive.

 -- Function: test.support.os_helper.make_bad_fd ()

     Create an invalid file descriptor by opening and closing a
     temporary file, and returning its descriptor.

 -- Function: test.support.os_helper.rmdir (filename)

     Call *note os.rmdir(): 1137. on 'filename'.  On Windows platforms,
     this is wrapped with a wait loop that checks for the existence of
     the file, which is needed due to antivirus programs that can hold
     files open and prevent deletion.

 -- Function: test.support.os_helper.rmtree (path)

     Call *note shutil.rmtree(): 301. on 'path' or call *note
     os.lstat(): 4a4. and *note os.rmdir(): 1137. to remove a path and
     its contents.  As with *note rmdir(): 4402, on Windows platforms
     this is wrapped with a wait loop that checks for the existence of
     the files.

 -- Function: @test.support.os_helper.skip_unless_symlink

     A decorator for running tests that require support for symbolic
     links.

 -- Function: @test.support.os_helper.skip_unless_xattr

     A decorator for running tests that require support for xattr.

 -- Function: test.support.os_helper.temp_cwd (name='tempcwd',
          quiet=False)

     A context manager that temporarily creates a new directory and
     changes the current working directory (CWD).

     The context manager creates a temporary directory in the current
     directory with name 'name' before temporarily changing the current
     working directory.  If 'name' is ‘None’, the temporary directory is
     created using *note tempfile.mkdtemp(): 21f.

     If 'quiet' is ‘False’ and it is not possible to create or change
     the CWD, an error is raised.  Otherwise, only a warning is raised
     and the original CWD is used.

 -- Function: test.support.os_helper.temp_dir (path=None, quiet=False)

     A context manager that creates a temporary directory at 'path' and
     yields the directory.

     If 'path' is ‘None’, the temporary directory is created using *note
     tempfile.mkdtemp(): 21f.  If 'quiet' is ‘False’, the context
     manager raises an exception on error.  Otherwise, if 'path' is
     specified and cannot be created, only a warning is issued.

 -- Function: test.support.os_helper.temp_umask (umask)

     A context manager that temporarily sets the process umask.

 -- Function: test.support.os_helper.unlink (filename)

     Call *note os.unlink(): 1139. on 'filename'.  As with *note
     rmdir(): 4402, on Windows platforms, this is wrapped with a wait
     loop that checks for the existence of the file.


File: python.info,  Node: test support import_helper — Utilities for import tests,  Next: test support warnings_helper — Utilities for warnings tests,  Prev: test support os_helper — Utilities for os tests,  Up: Development Tools

5.26.15 ‘test.support.import_helper’ — Utilities for import tests
-----------------------------------------------------------------

The ‘test.support.import_helper’ module provides support for import
tests.

Added in version 3.10.

 -- Function: test.support.import_helper.forget (module_name)

     Remove the module named 'module_name' from ‘sys.modules’ and delete
     any byte-compiled files of the module.

 -- Function: test.support.import_helper.import_fresh_module (name,
          fresh=(), blocked=(), deprecated=False)

     This function imports and returns a fresh copy of the named Python
     module by removing the named module from ‘sys.modules’ before doing
     the import.  Note that unlike ‘reload()’, the original module is
     not affected by this operation.

     'fresh' is an iterable of additional module names that are also
     removed from the ‘sys.modules’ cache before doing the import.

     'blocked' is an iterable of module names that are replaced with
     ‘None’ in the module cache during the import to ensure that
     attempts to import them raise *note ImportError: 41c.

     The named module and any modules named in the 'fresh' and 'blocked'
     parameters are saved before starting the import and then reinserted
     into ‘sys.modules’ when the fresh import is complete.

     Module and package deprecation messages are suppressed during this
     import if 'deprecated' is ‘True’.

     This function will raise *note ImportError: 41c. if the named
     module cannot be imported.

     Example use:

          # Get copies of the warnings module for testing without affecting the
          # version being used by the rest of the test suite. One copy uses the
          # C implementation, the other is forced to use the pure Python fallback
          # implementation
          py_warnings = import_fresh_module('warnings', blocked=['_warnings'])
          c_warnings = import_fresh_module('warnings', fresh=['_warnings'])

     Added in version 3.1.

 -- Function: test.support.import_helper.import_module (name,
          deprecated=False, *, required_on=())

     This function imports and returns the named module.  Unlike a
     normal import, this function raises *note unittest.SkipTest: 101f.
     if the module cannot be imported.

     Module and package deprecation messages are suppressed during this
     import if 'deprecated' is ‘True’.  If a module is required on a
     platform but optional for others, set 'required_on' to an iterable
     of platform prefixes which will be compared against *note
     sys.platform: a9c.

     Added in version 3.1.

 -- Function: test.support.import_helper.modules_setup ()

     Return a copy of *note sys.modules: 1655.

 -- Function: test.support.import_helper.modules_cleanup (oldmodules)

     Remove modules except for 'oldmodules' and ‘encodings’ in order to
     preserve internal cache.

 -- Function: test.support.import_helper.unload (name)

     Delete 'name' from ‘sys.modules’.

 -- Function: test.support.import_helper.make_legacy_pyc (source)

     Move a PEP 3147(1)/ PEP 488(2) pyc file to its legacy pyc location
     and return the file system path to the legacy pyc file.  The
     'source' value is the file system path to the source file.  It does
     not need to exist, however the PEP 3147/488 pyc file must exist.

 -- Class: test.support.import_helper.CleanImport (*module_names)

     A context manager to force import to return a new module reference.
     This is useful for testing module-level behaviors, such as the
     emission of a *note DeprecationWarning: 1a5. on import.  Example
     usage:

          with CleanImport('foo'):
              importlib.import_module('foo')  # New reference.

 -- Class: test.support.import_helper.DirsOnSysPath (*paths)

     A context manager to temporarily add directories to *note sys.path:
     3b7.

     This makes a copy of *note sys.path: 3b7, appends any directories
     given as positional arguments, then reverts ‘sys.path’ to the
     copied settings when the context ends.

     Note that 'all' *note sys.path: 3b7. modifications in the body of
     the context manager, including replacement of the object, will be
     reverted at the end of the block.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/

   (2) https://peps.python.org/pep-0488/


File: python.info,  Node: test support warnings_helper — Utilities for warnings tests,  Prev: test support import_helper — Utilities for import tests,  Up: Development Tools

5.26.16 ‘test.support.warnings_helper’ — Utilities for warnings tests
---------------------------------------------------------------------

The ‘test.support.warnings_helper’ module provides support for warnings
tests.

Added in version 3.10.

 -- Function: test.support.warnings_helper.ignore_warnings (*, category)

     Suppress warnings that are instances of 'category', which must be
     *note Warning: 246c. or a subclass.  Roughly equivalent to *note
     warnings.catch_warnings(): 587. with *note
     warnings.simplefilter('ignore', category=category): 6c4.  For
     example:

          @warning_helper.ignore_warnings(category=DeprecationWarning)
          def test_suppress_warning():
              # do something

     Added in version 3.8.

 -- Function: test.support.warnings_helper.check_no_resource_warning
          (testcase)

     Context manager to check that no *note ResourceWarning: 244. was
     raised.  You must remove the object which may emit
     ‘ResourceWarning’ before the end of the context manager.

 -- Function: test.support.warnings_helper.check_syntax_warning
          (testcase, statement, errtext='', *, lineno=1, offset=None)

     Test for syntax warning in 'statement' by attempting to compile
     'statement'.  Test also that the *note SyntaxWarning: 469. is
     emitted only once, and that it will be converted to a *note
     SyntaxError: 18d. when turned into error.  'testcase' is the *note
     unittest: 106. instance for the test.  'errtext' is the regular
     expression which should match the string representation of the
     emitted ‘SyntaxWarning’ and raised ‘SyntaxError’.  If 'lineno' is
     not ‘None’, compares to the line of the warning and exception.  If
     'offset' is not ‘None’, compares to the offset of the exception.

     Added in version 3.8.

 -- Function: test.support.warnings_helper.check_warnings (*filters,
          quiet=True)

     A convenience wrapper for *note warnings.catch_warnings(): 587.
     that makes it easier to test that a warning was correctly raised.
     It is approximately equivalent to calling
     ‘warnings.catch_warnings(record=True)’ with *note
     warnings.simplefilter(): 6c4. set to ‘always’ and with the option
     to automatically validate the results that are recorded.

     ‘check_warnings’ accepts 2-tuples of the form ‘("message regexp",
     WarningCategory)’ as positional arguments.  If one or more
     'filters' are provided, or if the optional keyword argument 'quiet'
     is ‘False’, it checks to make sure the warnings are as expected:
     each specified filter must match at least one of the warnings
     raised by the enclosed code or the test fails, and if any warnings
     are raised that do not match any of the specified filters the test
     fails.  To disable the first of these checks, set 'quiet' to
     ‘True’.

     If no arguments are specified, it defaults to:

          check_warnings(("", Warning), quiet=True)

     In this case all warnings are caught and no errors are raised.

     On entry to the context manager, a ‘WarningRecorder’ instance is
     returned.  The underlying warnings list from *note
     catch_warnings(): 587. is available via the recorder object’s *note
     warnings: 112. attribute.  As a convenience, the attributes of the
     object representing the most recent warning can also be accessed
     directly through the recorder object (see example below).  If no
     warning has been raised, then any of the attributes that would
     otherwise be expected on an object representing a warning will
     return ‘None’.

     The recorder object also has a ‘reset()’ method, which clears the
     warnings list.

     The context manager is designed to be used like this:

          with check_warnings(("assertion is always true", SyntaxWarning),
                              ("", UserWarning)):
              exec('assert(False, "Hey!")')
              warnings.warn(UserWarning("Hide me!"))

     In this case if either warning was not raised, or some other
     warning was raised, ‘check_warnings()’ would raise an error.

     When a test needs to look more deeply into the warnings, rather
     than just checking whether or not they occurred, code like this can
     be used:

          with check_warnings(quiet=True) as w:
              warnings.warn("foo")
              assert str(w.args[0]) == "foo"
              warnings.warn("bar")
              assert str(w.args[0]) == "bar"
              assert str(w.warnings[0].args[0]) == "foo"
              assert str(w.warnings[1].args[0]) == "bar"
              w.reset()
              assert len(w.warnings) == 0

     Here all warnings will be caught, and the test code tests the
     captured warnings directly.

     Changed in version 3.2: New optional arguments 'filters' and
     'quiet'.

 -- Class: test.support.warnings_helper.WarningsRecorder

     Class used to record warnings for unit tests.  See documentation of
     *note check_warnings(): 4417. above for more details.


File: python.info,  Node: Debugging and Profiling,  Next: Software Packaging and Distribution,  Prev: Development Tools,  Up: The Python Standard Library

5.27 Debugging and Profiling
============================

These libraries help you with Python development: the debugger enables
you to step through code, analyze stack frames and set breakpoints etc.,
and the profilers run code and give you a detailed breakdown of
execution times, allowing you to identify bottlenecks in your programs.
Auditing events provide visibility into runtime behaviors that would
otherwise require intrusive debugging or patching.

* Menu:

* Audit events table::
* bdb — Debugger framework::
* faulthandler — Dump the Python traceback::
* pdb — The Python Debugger::
* The Python Profilers::
* timeit — Measure execution time of small code snippets::
* trace — Trace or track Python statement execution::
* tracemalloc — Trace memory allocations::


File: python.info,  Node: Audit events table,  Next: bdb — Debugger framework,  Up: Debugging and Profiling

5.27.1 Audit events table
-------------------------

This table contains all events raised by *note sys.audit(): 16be. or
*note PySys_Audit(): 372. calls throughout the CPython runtime and the
standard library.  These calls were added in 3.8 or later (see PEP
578(1)).

See *note sys.addaudithook(): 441e. and *note PySys_AddAuditHook():
441f. for information on handling these events.

'CPython implementation detail:' This table is generated from the
CPython documentation, and may not represent events raised by other
implementations.  See your runtime specific documentation for actual
events raised.

Audit event                        Arguments                                                   References
                                                                                               
-------------------------------------------------------------------------------------------------------------------
                                                                                               
_thread.start_new_thread           ‘function’, ‘args’, ‘kwargs’                                *note [1]: 4420.
                                                                                               
                                                                                               
array.__new__                      ‘typecode’, ‘initializer’                                   *note [1]: 1a0.
                                                                                               
                                                                                               
builtins.breakpoint                ‘breakpointhook’                                            *note [1]: 234.
                                                                                               
                                                                                               
builtins.id                        ‘id’                                                        *note [1]: 1471.
                                                                                               
                                                                                               
builtins.input                     ‘prompt’                                                    *note [1]: 1320.
                                                                                               
                                                                                               
builtins.input/result              ‘result’                                                    *note [1]: 1320.
                                                                                               
                                                                                               
code.__new__                       ‘code’, ‘filename’, ‘name’, ‘argcount’,                     *note [1]: 2df.
                                   ‘posonlyargcount’, ‘kwonlyargcount’, ‘nlocals’,             
                                   ‘stacksize’, ‘flags’
                                   
                                                                                               
compile                            ‘source’, ‘filename’                                        *note [1]: 192.
                                                                                               
                                                                                               
cpython.PyInterpreterState_Clear                                                               *note [1]: 4421.
                                                                                               
                                                                                               
cpython.PyInterpreterState_New                                                                 *note [1]: 4422.
                                                                                               
                                                                                               
cpython._PySys_ClearAuditHooks                                                                 *note [1]: d3d.
                                                                                               
                                                                                               
cpython.run_command                ‘command’                                                   *note [1]: 5e3.
                                                                                               
                                                                                               
cpython.run_file                   ‘filename’                                                  *note [1]: 4423.
                                                                                               
                                                                                               
cpython.run_interactivehook        ‘hook’                                                      *note [1]: 1002.
                                                                                               
                                                                                               
cpython.run_module                 ‘module-name’                                               *note [1]: 5e4.
                                                                                               
                                                                                               
cpython.run_startup                ‘filename’                                                  *note [1]: 1003.
                                                                                               
                                                                                               
cpython.run_stdin                                                                              *note [1]: 4424.*note [2]: 4425.*note [3]: 4426.
                                                                                               
                                                                                               
ctypes.addressof                   ‘obj’                                                       *note [1]: 3035.
                                                                                               
                                                                                               
ctypes.call_function               ‘func_pointer’, ‘arguments’                                 *note [1]: 302d.
                                                                                               
                                                                                               
ctypes.cdata                       ‘address’                                                   *note [1]: 3047.
                                                                                               
                                                                                               
ctypes.cdata/buffer                ‘pointer’, ‘size’, ‘offset’                                 *note [1]: 3045.*note [2]: 3046.
                                                                                               
                                                                                               
ctypes.create_string_buffer        ‘init’, ‘size’                                              *note [1]: 2feb.
                                                                                               
                                                                                               
ctypes.create_unicode_buffer       ‘init’, ‘size’                                              *note [1]: 1b5f.
                                                                                               
                                                                                               
ctypes.dlopen                      ‘name’                                                      *note [1]: 302b.
                                                                                               
                                                                                               
ctypes.dlsym                       ‘library’, ‘name’                                           *note [1]: 302b.
                                                                                               
                                                                                               
ctypes.dlsym/handle                ‘handle’, ‘name’                                            *note [1]: 302b.
                                                                                               
                                                                                               
ctypes.get_errno                                                                               *note [1]: 3025.
                                                                                               
                                                                                               
ctypes.get_last_error                                                                          *note [1]: 3027.
                                                                                               
                                                                                               
ctypes.set_errno                   ‘errno’                                                     *note [1]: 3026.
                                                                                               
                                                                                               
ctypes.set_exception               ‘code’                                                      *note [1]: 302d.
                                                                                               
                                                                                               
ctypes.set_last_error              ‘error’                                                     *note [1]: 3028.
                                                                                               
                                                                                               
ctypes.string_at                   ‘ptr’, ‘size’                                               *note [1]: 303e.
                                                                                               
                                                                                               
ctypes.wstring_at                  ‘ptr’, ‘size’                                               *note [1]: 3040.
                                                                                               
                                                                                               
ensurepip.bootstrap                ‘root’                                                      *note [1]: 4427.
                                                                                               
                                                                                               
exec                               ‘code_object’                                               *note [1]: 180.*note [2]: 17f.
                                                                                               
                                                                                               
fcntl.fcntl                        ‘fd’, ‘cmd’, ‘arg’                                          *note [1]: 3670.
                                                                                               
                                                                                               
fcntl.flock                        ‘fd’, ‘operation’                                           *note [1]: 4428.
                                                                                               
                                                                                               
fcntl.ioctl                        ‘fd’, ‘request’, ‘arg’                                      *note [1]: 14ca.
                                                                                               
                                                                                               
fcntl.lockf                        ‘fd’, ‘cmd’, ‘len’, ‘start’, ‘whence’                       *note [1]: 143a.
                                                                                               
                                                                                               
ftplib.connect                     ‘self’, ‘host’, ‘port’                                      *note [1]: 3cd3.
                                                                                               
                                                                                               
ftplib.sendcmd                     ‘self’, ‘cmd’                                               *note [1]: 3cd8.*note [2]: 3cd9.
                                                                                               
                                                                                               
function.__new__                   ‘code’                                                      *note [1]: 88a.
                                                                                               
                                                                                               
gc.get_objects                     ‘generation’                                                *note [1]: 809.
                                                                                               
                                                                                               
gc.get_referents                   ‘objs’                                                      *note [1]: 80b.
                                                                                               
                                                                                               
gc.get_referrers                   ‘objs’                                                      *note [1]: 80a.
                                                                                               
                                                                                               
glob.glob                          ‘pathname’, ‘recursive’                                     *note [1]: 29f.*note [2]: 80d.
                                                                                               
                                                                                               
glob.glob/2                        ‘pathname’, ‘recursive’, ‘root_dir’, ‘dir_fd’               *note [1]: 29f.*note [2]: 80d.
                                                                                               
                                                                                               
http.client.connect                ‘self’, ‘host’, ‘port’                                      *note [1]: 3cb6.
                                                                                               
                                                                                               
http.client.send                   ‘self’, ‘data’                                              *note [1]: 3cba.
                                                                                               
                                                                                               
imaplib.open                       ‘self’, ‘host’, ‘port’                                      *note [1]: 90e.
                                                                                               
                                                                                               
imaplib.send                       ‘self’, ‘data’                                              *note [1]: 3d29.
                                                                                               
                                                                                               
import                             ‘module’, ‘filename’, ‘sys.path’, ‘sys.meta_path’,          *note [1]: 5e5.
                                   ‘sys.path_hooks’                                            
                                   
                                                                                               
marshal.dumps                      ‘value’, ‘version’                                          *note [1]: 2a92.
                                                                                               
                                                                                               
marshal.load                                                                                   *note [1]: 1ba4.
                                                                                               
                                                                                               
marshal.loads                      ‘bytes’                                                     *note [1]: 1ba4.
                                                                                               
                                                                                               
mmap.__new__                       ‘fileno’, ‘length’, ‘access’, ‘offset’                      *note [1]: 20b.
                                                                                               
                                                                                               
msvcrt.get_osfhandle               ‘fd’                                                        *note [1]: 4429.
                                                                                               
                                                                                               
msvcrt.locking                     ‘fd’, ‘mode’, ‘nbytes’                                      *note [1]: 442a.
                                                                                               
                                                                                               
msvcrt.open_osfhandle              ‘handle’, ‘flags’                                           *note [1]: 442b.
                                                                                               
                                                                                               
object.__delattr__                 ‘obj’, ‘name’                                               *note [1]: 20df.
                                                                                               
                                                                                               
object.__getattr__                 ‘obj’, ‘name’                                               *note [1]: bf1.
                                                                                               
                                                                                               
object.__setattr__                 ‘obj’, ‘name’, ‘value’                                      *note [1]: 20de.
                                                                                               
                                                                                               
open                               ‘path’, ‘mode’, ‘flags’                                     *note [1]: 51f.*note [2]: 520.*note [3]: dc0.
                                                                                               
                                                                                               
os.add_dll_directory               ‘path’                                                      *note [1]: 9f5.
                                                                                               
                                                                                               
os.chdir                           ‘path’                                                      *note [1]: 610.*note [2]: db7.
                                                                                               
                                                                                               
os.chflags                         ‘path’, ‘flags’                                             *note [1]: 1131.*note [2]: 2d78.
                                                                                               
                                                                                               
os.chmod                           ‘path’, ‘mode’, ‘dir_fd’                                    *note [1]: 21b.*note [2]: 21c.*note [3]: 21a.
                                                                                               
                                                                                               
os.chown                           ‘path’, ‘uid’, ‘gid’, ‘dir_fd’                              *note [1]: 1132.*note [2]: db8.*note [3]: 2d79.
                                                                                               
                                                                                               
os.exec                            ‘path’, ‘args’, ‘env’                                       *note [1]: 2db2.
                                                                                               
                                                                                               
os.fork                                                                                        *note [1]: 197.
                                                                                               
                                                                                               
os.forkpty                                                                                     *note [1]: 198.
                                                                                               
                                                                                               
os.fwalk                           ‘top’, ‘topdown’, ‘onerror’, ‘follow_symlinks’, ‘dir_fd’    *note [1]: b77.
                                                                                               
                                                                                               
os.getxattr                        ‘path’, ‘attribute’                                         *note [1]: 1148.
                                                                                               
                                                                                               
os.kill                            ‘pid’, ‘sig’                                                *note [1]: 13b4.
                                                                                               
                                                                                               
os.killpg                          ‘pgid’, ‘sig’                                               *note [1]: 1b66.
                                                                                               
                                                                                               
os.link                            ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’                    *note [1]: 1133.
                                                                                               
                                                                                               
os.listdir                         ‘path’                                                      *note [1]: 113e.
                                                                                               
                                                                                               
os.listdrives                                                                                  *note [1]: 4a0.
                                                                                               
                                                                                               
os.listmounts                      ‘volume’                                                    *note [1]: 4a2.
                                                                                               
                                                                                               
os.listvolumes                                                                                 *note [1]: 4a1.
                                                                                               
                                                                                               
os.listxattr                       ‘path’                                                      *note [1]: 1149.
                                                                                               
                                                                                               
os.lockf                           ‘fd’, ‘cmd’, ‘len’                                          *note [1]: 1157.
                                                                                               
                                                                                               
os.mkdir                           ‘path’, ‘mode’, ‘dir_fd’                                    *note [1]: 21e.*note [2]: 21d.
                                                                                               
                                                                                               
os.posix_spawn                     ‘path’, ‘argv’, ‘env’                                       *note [1]: 220.*note [2]: 15b4.
                                                                                               
                                                                                               
os.putenv                          ‘key’, ‘value’                                              *note [1]: 925.
                                                                                               
                                                                                               
os.remove                          ‘path’, ‘dir_fd’                                            *note [1]: 1134.*note [2]: 2d7d.*note [3]: 1139.
                                                                                               
                                                                                               
os.removexattr                     ‘path’, ‘attribute’                                         *note [1]: 114a.
                                                                                               
                                                                                               
os.rename                          ‘src’, ‘dst’, ‘src_dir_fd’, ‘dst_dir_fd’                    *note [1]: 1135.*note [2]: 2d7e.*note [3]: 1136.
                                                                                               
                                                                                               
os.rmdir                           ‘path’, ‘dir_fd’                                            *note [1]: 1137.
                                                                                               
                                                                                               
os.scandir                         ‘path’                                                      *note [1]: a6d.
                                                                                               
                                                                                               
os.setxattr                        ‘path’, ‘attribute’, ‘value’, ‘flags’                       *note [1]: 114b.
                                                                                               
                                                                                               
os.spawn                           ‘mode’, ‘path’, ‘args’, ‘env’                               *note [1]: 1842.
                                                                                               
                                                                                               
os.startfile                       ‘path’, ‘operation’                                         *note [1]: 1a29.
                                                                                               
                                                                                               
os.startfile/2                     ‘path’, ‘operation’, ‘arguments’, ‘cwd’, ‘show_cmd’         *note [1]: 1a29.
                                                                                               
                                                                                               
os.symlink                         ‘src’, ‘dst’, ‘dir_fd’                                      *note [1]: 1138.
                                                                                               
                                                                                               
os.system                          ‘command’                                                   *note [1]: 14ac.
                                                                                               
                                                                                               
os.truncate                        ‘fd’, ‘length’                                              *note [1]: dbd.*note [2]: e6f.
                                                                                               
                                                                                               
os.unsetenv                        ‘key’                                                       *note [1]: 924.
                                                                                               
                                                                                               
os.utime                           ‘path’, ‘times’, ‘ns’, ‘dir_fd’                             *note [1]: 113a.
                                                                                               
                                                                                               
os.walk                            ‘top’, ‘topdown’, ‘onerror’, ‘followlinks’                  *note [1]: 4ac.
                                                                                               
                                                                                               
pathlib.Path.glob                  ‘self’, ‘pattern’                                           *note [1]: 22d.
                                                                                               
                                                                                               
pathlib.Path.rglob                 ‘self’, ‘pattern’                                           *note [1]: 22e.
                                                                                               
                                                                                               
pdb.Pdb                                                                                        *note [1]: 92b.
                                                                                               
                                                                                               
pickle.find_class                  ‘module’, ‘name’                                            *note [1]: 2a6d.
                                                                                               
                                                                                               
poplib.connect                     ‘self’, ‘host’, ‘port’                                      *note [1]: 92d.*note [2]: 92e.
                                                                                               
                                                                                               
poplib.putline                     ‘self’, ‘line’                                              *note [1]: 92d.*note [2]: 92e.
                                                                                               
                                                                                               
pty.spawn                          ‘argv’                                                      *note [1]: fbb.
                                                                                               
                                                                                               
resource.prlimit                   ‘pid’, ‘resource’, ‘limits’                                 *note [1]: fc3.
                                                                                               
                                                                                               
resource.setrlimit                 ‘resource’, ‘limits’                                        *note [1]: 1625.
                                                                                               
                                                                                               
setopencodehook                                                                                *note [1]: 183a.
                                                                                               
                                                                                               
shutil.chown                       ‘path’, ‘user’, ‘group’                                     *note [1]: 240.
                                                                                               
                                                                                               
shutil.copyfile                    ‘src’, ‘dst’                                                *note [1]: a68.*note [2]: a69.*note [3]: a67.
                                                                                               
                                                                                               
shutil.copymode                    ‘src’, ‘dst’                                                *note [1]: a68.*note [2]: 17bc.
                                                                                               
                                                                                               
shutil.copystat                    ‘src’, ‘dst’                                                *note [1]: a69.*note [2]: 1172.
                                                                                               
                                                                                               
shutil.copytree                    ‘src’, ‘dst’                                                *note [1]: a36.
                                                                                               
                                                                                               
shutil.make_archive                ‘base_name’, ‘format’, ‘root_dir’, ‘base_dir’               *note [1]: 4b6.
                                                                                               
                                                                                               
shutil.move                        ‘src’, ‘dst’                                                *note [1]: a6a.
                                                                                               
                                                                                               
shutil.rmtree                      ‘path’, ‘dir_fd’                                            *note [1]: 301.
                                                                                               
                                                                                               
shutil.unpack_archive              ‘filename’, ‘extract_dir’, ‘format’                         *note [1]: 46e.
                                                                                               
                                                                                               
signal.pthread_kill                ‘thread_id’, ‘signalnum’                                    *note [1]: 1175.
                                                                                               
                                                                                               
smtplib.connect                    ‘self’, ‘host’, ‘port’                                      *note [1]: 1b5a.
                                                                                               
                                                                                               
smtplib.send                       ‘self’, ‘data’                                              *note [1]: 937.
                                                                                               
                                                                                               
socket.__new__                     ‘self’, ‘family’, ‘type’, ‘protocol’                        *note [1]: dcf.
                                                                                               
                                                                                               
socket.bind                        ‘self’, ‘address’                                           *note [1]: 158a.
                                                                                               
                                                                                               
socket.connect                     ‘self’, ‘address’                                           *note [1]: dd1.*note [2]: 1589.
                                                                                               
                                                                                               
socket.getaddrinfo                 ‘host’, ‘port’, ‘family’, ‘type’, ‘protocol’                *note [1]: 15ba.
                                                                                               
                                                                                               
socket.gethostbyaddr               ‘ip_address’                                                *note [1]: 1a2a.
                                                                                               
                                                                                               
socket.gethostbyname               ‘hostname’                                                  *note [1]: 3665.*note [2]: 1a2b.
                                                                                               
                                                                                               
socket.gethostname                                                                             *note [1]: 2d23.
                                                                                               
                                                                                               
socket.getnameinfo                 ‘sockaddr’                                                  *note [1]: 17d3.
                                                                                               
                                                                                               
socket.getservbyname               ‘servicename’, ‘protocolname’                               *note [1]: 3667.
                                                                                               
                                                                                               
socket.getservbyport               ‘port’, ‘protocolname’                                      *note [1]: 3668.
                                                                                               
                                                                                               
socket.sendmsg                     ‘self’, ‘address’                                           *note [1]: 479.
                                                                                               
                                                                                               
socket.sendto                      ‘self’, ‘address’                                           *note [1]: dd7.
                                                                                               
                                                                                               
socket.sethostname                 ‘name’                                                      *note [1]: 117f.
                                                                                               
                                                                                               
sqlite3.connect                    ‘database’                                                  *note [1]: 2a8.
                                                                                               
                                                                                               
sqlite3.connect/handle             ‘connection_handle’                                         *note [1]: 2a8.
                                                                                               
                                                                                               
sqlite3.enable_load_extension      ‘connection’, ‘enabled’                                     *note [1]: 844.
                                                                                               
                                                                                               
sqlite3.load_extension             ‘connection’, ‘path’                                        *note [1]: 4bb.
                                                                                               
                                                                                               
subprocess.Popen                   ‘executable’, ‘args’, ‘cwd’, ‘env’                          *note [1]: 199.
                                                                                               
                                                                                               
sys._current_exceptions                                                                        *note [1]: 4c5.
                                                                                               
                                                                                               
sys._current_frames                                                                            *note [1]: 1481.
                                                                                               
                                                                                               
sys._getframe                      ‘frame’                                                     *note [1]: 6e4.
                                                                                               
                                                                                               
sys._getframemodulename            ‘depth’                                                     *note [1]: 1882.
                                                                                               
                                                                                               
sys.addaudithook                                                                               *note [1]: 441f.*note [2]: 441e.
                                                                                               
                                                                                               
sys.excepthook                     ‘hook’, ‘type’, ‘value’, ‘traceback’                        *note [1]: 811.
                                                                                               
                                                                                               
sys.monitoring.register_callback   ‘func’                                                      *note [1]: 442c.
                                                                                               
                                                                                               
sys.set_asyncgen_hooks_finalizer                                                               *note [1]: 1730.
                                                                                               
                                                                                               
sys.set_asyncgen_hooks_firstiter                                                               *note [1]: 1730.
                                                                                               
                                                                                               
sys.setprofile                                                                                 *note [1]: 154d.
                                                                                               
                                                                                               
sys.settrace                                                                                   *note [1]: 154e.
                                                                                               
                                                                                               
sys.unraisablehook                 ‘hook’, ‘unraisable’                                        *note [1]: 1f7.
                                                                                               
                                                                                               
syslog.closelog                                                                                *note [1]: 542.
                                                                                               
                                                                                               
syslog.openlog                     ‘ident’, ‘logoption’, ‘facility’                            *note [1]: 541.
                                                                                               
                                                                                               
syslog.setlogmask                  ‘maskpri’                                                   *note [1]: 442d.
                                                                                               
                                                                                               
syslog.syslog                      ‘priority’, ‘message’                                       *note [1]: 543.
                                                                                               
                                                                                               
tempfile.mkdtemp                   ‘fullpath’                                                  *note [1]: 127a.*note [2]: 21f.
                                                                                               
                                                                                               
tempfile.mkstemp                   ‘fullpath’                                                  *note [1]: 4c9.*note [2]: 2a1e.*note [3]: 2a1f.
                                                                                               
                                                                                               
time.sleep                         ‘secs’                                                      *note [1]: 442e.
                                                                                               
                                                                                               
urllib.Request                     ‘fullurl’, ‘data’, ‘headers’, ‘method’                      *note [1]: 293.
                                                                                               
                                                                                               
webbrowser.open                    ‘url’                                                       *note [1]: 15a8.
                                                                                               
                                                                                               
winreg.ConnectRegistry             ‘computer_name’, ‘key’                                      *note [1]: 442f.
                                                                                               
                                                                                               
winreg.CreateKey                   ‘key’, ‘sub_key’, ‘access’                                  *note [1]: 4430.*note [2]: 13af.
                                                                                               
                                                                                               
winreg.DeleteKey                   ‘key’, ‘sub_key’, ‘access’                                  *note [1]: 4431.*note [2]: 13b0.
                                                                                               
                                                                                               
winreg.DeleteValue                 ‘key’, ‘value’                                              *note [1]: 4432.
                                                                                               
                                                                                               
winreg.DisableReflectionKey        ‘key’                                                       *note [1]: 13b1.
                                                                                               
                                                                                               
winreg.EnableReflectionKey         ‘key’                                                       *note [1]: 13b2.
                                                                                               
                                                                                               
winreg.EnumKey                     ‘key’, ‘index’                                              *note [1]: 4433.
                                                                                               
                                                                                               
winreg.EnumValue                   ‘key’, ‘index’                                              *note [1]: 4434.
                                                                                               
                                                                                               
winreg.ExpandEnvironmentStrings    ‘str’                                                       *note [1]: 1446.
                                                                                               
                                                                                               
winreg.LoadKey                     ‘key’, ‘sub_key’, ‘file_name’                               *note [1]: 4435.
                                                                                               
                                                                                               
winreg.OpenKey                     ‘key’, ‘sub_key’, ‘access’                                  *note [1]: 4436.
                                                                                               
                                                                                               
winreg.OpenKey/result              ‘key’                                                       *note [1]: 4430.*note [2]: 13af.*note [3]: 4436.
                                                                                               
                                                                                               
winreg.PyHKEY.Detach               ‘key’                                                       *note [1]: 4437.
                                                                                               
                                                                                               
winreg.QueryInfoKey                ‘key’                                                       *note [1]: 4438.
                                                                                               
                                                                                               
winreg.QueryReflectionKey          ‘key’                                                       *note [1]: 13b3.
                                                                                               
                                                                                               
winreg.QueryValue                  ‘key’, ‘sub_key’, ‘value_name’                              *note [1]: 4439.*note [2]: 15cf.
                                                                                               
                                                                                               
winreg.SaveKey                     ‘key’, ‘file_name’                                          *note [1]: 443a.
                                                                                               
                                                                                               
winreg.SetValue                    ‘key’, ‘sub_key’, ‘type’, ‘value’                           *note [1]: 443b.*note [2]: 18a6.
                                                                                               

The following events are raised internally and do not correspond to any
public API of CPython:

Audit event                    Arguments
                               
-------------------------------------------------------------------------------
                               
_winapi.CreateFile             ‘file_name’, ‘desired_access’, ‘share_mode’,
                               ‘creation_disposition’,
                               ‘flags_and_attributes’
                               
                               
_winapi.CreateJunction         ‘src_path’, ‘dst_path’
                               
                               
_winapi.CreateNamedPipe        ‘name’, ‘open_mode’, ‘pipe_mode’
                               
                               
_winapi.CreatePipe

_winapi.CreateProcess          ‘application_name’, ‘command_line’,
                               ‘current_directory’
                               
                               
_winapi.OpenProcess            ‘process_id’, ‘desired_access’
                               
                               
_winapi.TerminateProcess       ‘handle’, ‘exit_code’
                               
                               
ctypes.PyObj_FromPtr           ‘obj’
                               

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0578/


File: python.info,  Node: bdb — Debugger framework,  Next: faulthandler — Dump the Python traceback,  Prev: Audit events table,  Up: Debugging and Profiling

5.27.2 ‘bdb’ — Debugger framework
---------------------------------

'Source code:' Lib/bdb.py(1)

__________________________________________________________________

The ‘bdb’ module handles basic debugger functions, like setting
breakpoints or managing execution via the debugger.

The following exception is defined:

 -- Exception: bdb.BdbQuit

     Exception raised by the *note Bdb: 134b. class for quitting the
     debugger.

The ‘bdb’ module also defines two classes:

 -- Class: bdb.Breakpoint (self, file, line, temporary=False, cond=None,
          funcname=None)

     This class implements temporary breakpoints, ignore counts,
     disabling and (re-)enabling, and conditionals.

     Breakpoints are indexed by number through a list called *note
     bpbynumber: 4441. and by ‘(file, line)’ pairs through *note bplist:
     4442.  The former points to a single instance of class
     ‘Breakpoint’.  The latter points to a list of such instances since
     there may be more than one breakpoint per line.

     When creating a breakpoint, its associated *note file name: 4443.
     should be in canonical form.  If a *note funcname: 4444. is
     defined, a breakpoint *note hit: 4445. will be counted when the
     first line of that function is executed.  A *note conditional:
     4446. breakpoint always counts a ‘hit’.

     ‘Breakpoint’ instances have the following methods:

      -- Method: deleteMe ()

          Delete the breakpoint from the list associated to a file/line.
          If it is the last breakpoint in that position, it also deletes
          the entry for the file/line.

      -- Method: enable ()

          Mark the breakpoint as enabled.

      -- Method: disable ()

          Mark the breakpoint as disabled.

      -- Method: bpformat ()

          Return a string with all the information about the breakpoint,
          nicely formatted:

             * Breakpoint number.

             * Temporary status (del or keep).

             * File/line position.

             * Break condition.

             * Number of times to ignore.

             * Number of times hit.

          Added in version 3.2.

      -- Method: bpprint (out=None)

          Print the output of *note bpformat(): 444a. to the file 'out',
          or if it is ‘None’, to standard output.

     ‘Breakpoint’ instances have the following attributes:

      -- Attribute: file

          File name of the ‘Breakpoint’.

      -- Attribute: line

          Line number of the ‘Breakpoint’ within *note file: 4443.

      -- Attribute: temporary

          ‘True’ if a ‘Breakpoint’ at (file, line) is temporary.

      -- Attribute: cond

          Condition for evaluating a ‘Breakpoint’ at (file, line).

      -- Attribute: funcname

          Function name that defines whether a ‘Breakpoint’ is hit upon
          entering the function.

      -- Attribute: enabled

          ‘True’ if ‘Breakpoint’ is enabled.

      -- Attribute: bpbynumber

          Numeric index for a single instance of a ‘Breakpoint’.

      -- Attribute: bplist

          Dictionary of ‘Breakpoint’ instances indexed by (*note file:
          4443, *note line: 444c.) tuples.

      -- Attribute: ignore

          Number of times to ignore a ‘Breakpoint’.

      -- Attribute: hits

          Count of the number of times a ‘Breakpoint’ has been hit.

 -- Class: bdb.Bdb (skip=None)

     The ‘Bdb’ class acts as a generic Python debugger base class.

     This class takes care of the details of the trace facility; a
     derived class should implement user interaction.  The standard
     debugger class (*note pdb.Pdb: 92b.) is an example.

     The 'skip' argument, if given, must be an iterable of glob-style
     module name patterns.  The debugger will not step into frames that
     originate in a module that matches one of these patterns.  Whether
     a frame is considered to originate in a certain module is
     determined by the ‘__name__’ in the frame globals.

     Changed in version 3.1: Added the 'skip' parameter.

     The following methods of ‘Bdb’ normally don’t need to be
     overridden.

      -- Method: canonic (filename)

          Return canonical form of 'filename'.

          For real file names, the canonical form is an
          operating-system-dependent, *note case-normalized: 29ab. *note
          absolute path: 1364.  A 'filename' with angle brackets, such
          as ‘"<stdin>"’ generated in interactive mode, is returned
          unchanged.

      -- Method: reset ()

          Set the ‘botframe’, ‘stopframe’, ‘returnframe’ and *note
          quitting: 4452. attributes with values ready to start
          debugging.

      -- Method: trace_dispatch (frame, event, arg)

          This function is installed as the trace function of debugged
          frames.  Its return value is the new trace function (in most
          cases, that is, itself).

          The default implementation decides how to dispatch a frame,
          depending on the type of event (passed as a string) that is
          about to be executed.  'event' can be one of the following:

             * ‘"line"’: A new line of code is going to be executed.

             * ‘"call"’: A function is about to be called, or another
               code block entered.

             * ‘"return"’: A function or other code block is about to
               return.

             * ‘"exception"’: An exception has occurred.

             * ‘"c_call"’: A C function is about to be called.

             * ‘"c_return"’: A C function has returned.

             * ‘"c_exception"’: A C function has raised an exception.

          For the Python events, specialized functions (see below) are
          called.  For the C events, no action is taken.

          The 'arg' parameter depends on the previous event.

          See the documentation for *note sys.settrace(): 154e. for more
          information on the trace function.  For more information on
          code and frame objects, refer to *note The standard type
          hierarchy: 2094.

      -- Method: dispatch_line (frame)

          If the debugger should stop on the current line, invoke the
          *note user_line(): 4455. method (which should be overridden in
          subclasses).  Raise a *note BdbQuit: 443f. exception if the
          *note quitting: 4452. flag is set (which can be set from
          ‘user_line()’).  Return a reference to the *note
          trace_dispatch(): 4453. method for further tracing in that
          scope.

      -- Method: dispatch_call (frame, arg)

          If the debugger should stop on this function call, invoke the
          *note user_call(): 4457. method (which should be overridden in
          subclasses).  Raise a *note BdbQuit: 443f. exception if the
          *note quitting: 4452. flag is set (which can be set from
          ‘user_call()’).  Return a reference to the *note
          trace_dispatch(): 4453. method for further tracing in that
          scope.

      -- Method: dispatch_return (frame, arg)

          If the debugger should stop on this function return, invoke
          the *note user_return(): 4459. method (which should be
          overridden in subclasses).  Raise a *note BdbQuit: 443f.
          exception if the *note quitting: 4452. flag is set (which can
          be set from ‘user_return()’).  Return a reference to the *note
          trace_dispatch(): 4453. method for further tracing in that
          scope.

      -- Method: dispatch_exception (frame, arg)

          If the debugger should stop at this exception, invokes the
          *note user_exception(): 445b. method (which should be
          overridden in subclasses).  Raise a *note BdbQuit: 443f.
          exception if the *note quitting: 4452. flag is set (which can
          be set from ‘user_exception()’).  Return a reference to the
          *note trace_dispatch(): 4453. method for further tracing in
          that scope.

     Normally derived classes don’t override the following methods, but
     they may if they want to redefine the definition of stopping and
     breakpoints.

      -- Method: is_skipped_module (module_name)

          Return ‘True’ if 'module_name' matches any skip pattern.

      -- Method: stop_here (frame)

          Return ‘True’ if 'frame' is below the starting frame in the
          stack.

      -- Method: break_here (frame)

          Return ‘True’ if there is an effective breakpoint for this
          line.

          Check whether a line or function breakpoint exists and is in
          effect.  Delete temporary breakpoints based on information
          from *note effective(): 445f.

      -- Method: break_anywhere (frame)

          Return ‘True’ if any breakpoint exists for 'frame'’s filename.

     Derived classes should override these methods to gain control over
     debugger operation.

      -- Method: user_call (frame, argument_list)

          Called from *note dispatch_call(): 4456. if a break might stop
          inside the called function.

          'argument_list' is not used anymore and will always be ‘None’.
          The argument is kept for backwards compatibility.

      -- Method: user_line (frame)

          Called from *note dispatch_line(): 4454. when either *note
          stop_here(): 445d. or *note break_here(): 445e. returns
          ‘True’.

      -- Method: user_return (frame, return_value)

          Called from *note dispatch_return(): 4458. when *note
          stop_here(): 445d. returns ‘True’.

      -- Method: user_exception (frame, exc_info)

          Called from *note dispatch_exception(): 445a. when *note
          stop_here(): 445d. returns ‘True’.

      -- Method: do_clear (arg)

          Handle how a breakpoint must be removed when it is a temporary
          one.

          This method must be implemented by derived classes.

     Derived classes and clients can call the following methods to
     affect the stepping state.

      -- Method: set_step ()

          Stop after one line of code.

      -- Method: set_next (frame)

          Stop on the next line in or below the given frame.

      -- Method: set_return (frame)

          Stop when returning from the given frame.

      -- Method: set_until (frame, lineno=None)

          Stop when the line with the 'lineno' greater than the current
          one is reached or when returning from current frame.

      -- Method: set_trace ([frame])

          Start debugging from 'frame'.  If 'frame' is not specified,
          debugging starts from caller’s frame.

          Changed in version 3.13: *note set_trace(): 4467. will enter
          the debugger immediately, rather than on the next line of code
          to be executed.

      -- Method: set_continue ()

          Stop only at breakpoints or when finished.  If there are no
          breakpoints, set the system trace function to ‘None’.

      -- Method: set_quit ()

          Set the ‘quitting’ attribute to ‘True’.  This raises *note
          BdbQuit: 443f. in the next call to one of the ‘dispatch_*()’
          methods.

     Derived classes and clients can call the following methods to
     manipulate breakpoints.  These methods return a string containing
     an error message if something went wrong, or ‘None’ if all is well.

      -- Method: set_break (filename, lineno, temporary=False,
               cond=None, funcname=None)

          Set a new breakpoint.  If the 'lineno' line doesn’t exist for
          the 'filename' passed as argument, return an error message.
          The 'filename' should be in canonical form, as described in
          the *note canonic(): 4450. method.

      -- Method: clear_break (filename, lineno)

          Delete the breakpoints in 'filename' and 'lineno'.  If none
          were set, return an error message.

      -- Method: clear_bpbynumber (arg)

          Delete the breakpoint which has the index 'arg' in the *note
          Breakpoint.bpbynumber: 4441.  If 'arg' is not numeric or out
          of range, return an error message.

      -- Method: clear_all_file_breaks (filename)

          Delete all breakpoints in 'filename'.  If none were set,
          return an error message.

      -- Method: clear_all_breaks ()

          Delete all existing breakpoints.  If none were set, return an
          error message.

      -- Method: get_bpbynumber (arg)

          Return a breakpoint specified by the given number.  If 'arg'
          is a string, it will be converted to a number.  If 'arg' is a
          non-numeric string, if the given breakpoint never existed or
          has been deleted, a *note ValueError: 202. is raised.

          Added in version 3.2.

      -- Method: get_break (filename, lineno)

          Return ‘True’ if there is a breakpoint for 'lineno' in
          'filename'.

      -- Method: get_breaks (filename, lineno)

          Return all breakpoints for 'lineno' in 'filename', or an empty
          list if none are set.

      -- Method: get_file_breaks (filename)

          Return all breakpoints in 'filename', or an empty list if none
          are set.

      -- Method: get_all_breaks ()

          Return all breakpoints that are set.

     Derived classes and clients can call the following methods to get a
     data structure representing a stack trace.

      -- Method: get_stack (f, t)

          Return a list of (frame, lineno) tuples in a stack trace, and
          a size.

          The most recently called frame is last in the list.  The size
          is the number of frames below the frame where the debugger was
          invoked.

      -- Method: format_stack_entry (frame_lineno, lprefix=': ')

          Return a string with information about a stack entry, which is
          a ‘(frame, lineno)’ tuple.  The return string contains:

             * The canonical filename which contains the frame.

             * The function name or ‘"<lambda>"’.

             * The input arguments.

             * The return value.

             * The line of code (if it exists).

     The following two methods can be called by clients to use a
     debugger to debug a *note statement: 2951, given as a string.

      -- Method: run (cmd, globals=None, locals=None)

          Debug a statement executed via the *note exec(): 17f.
          function.  'globals' defaults to ‘__main__.__dict__’, 'locals'
          defaults to 'globals'.

      -- Method: runeval (expr, globals=None, locals=None)

          Debug an expression executed via the *note eval(): 180.
          function.  'globals' and 'locals' have the same meaning as in
          *note run(): 4475.

      -- Method: runctx (cmd, globals, locals)

          For backwards compatibility.  Calls the *note run(): 4475.
          method.

      -- Method: runcall (func, /, *args, **kwds)

          Debug a single function call, and return its result.

Finally, the module defines the following functions:

 -- Function: bdb.checkfuncname (b, frame)

     Return ‘True’ if we should break here, depending on the way the
     *note Breakpoint: 4440. 'b' was set.

     If it was set via line number, it checks if *note b.line: 444c. is
     the same as the one in 'frame'.  If the breakpoint was set via
     *note function name: 4444, we have to check we are in the right
     'frame' (the right function) and if we are on its first executable
     line.

 -- Function: bdb.effective (file, line, frame)

     Return ‘(active breakpoint, delete temporary flag)’ or ‘(None,
     None)’ as the breakpoint to act upon.

     The 'active breakpoint' is the first entry in *note bplist: 4442.
     for the (*note file: 4443, *note line: 444c.) (which must exist)
     that is *note enabled: 444e, for which *note checkfuncname(): 4478.
     is true, and that has neither a false *note condition: 4446. nor
     positive *note ignore: 444f. count.  The 'flag', meaning that a
     temporary breakpoint should be deleted, is ‘False’ only when the
     ‘cond’ cannot be evaluated (in which case, ‘ignore’ count is
     ignored).

     If no such entry exists, then ‘(None, None)’ is returned.

 -- Function: bdb.set_trace ()

     Start debugging with a *note Bdb: 134b. instance from caller’s
     frame.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/bdb.py


File: python.info,  Node: faulthandler — Dump the Python traceback,  Next: pdb — The Python Debugger,  Prev: bdb — Debugger framework,  Up: Debugging and Profiling

5.27.3 ‘faulthandler’ — Dump the Python traceback
-------------------------------------------------

Added in version 3.3.

__________________________________________________________________

This module contains functions to dump Python tracebacks explicitly, on
a fault, after a timeout, or on a user signal.  Call *note
faulthandler.enable(): cc4. to install fault handlers for the *note
SIGSEGV: 10be, *note SIGFPE: 10bf, *note SIGABRT: 10c0, *note SIGBUS:
10c1, and *note SIGILL: 10c2. signals.  You can also enable them at
startup by setting the *note PYTHONFAULTHANDLER: 10c3. environment
variable or by using the *note -X: 176. ‘faulthandler’ command line
option.

The fault handler is compatible with system fault handlers like Apport
or the Windows fault handler.  The module uses an alternative stack for
signal handlers if the ‘sigaltstack()’ function is available.  This
allows it to dump the traceback even on a stack overflow.

The fault handler is called on catastrophic cases and therefore can only
use signal-safe functions (e.g.  it cannot allocate memory on the heap).
Because of this limitation traceback dumping is minimal compared to
normal Python tracebacks:

   * Only ASCII is supported.  The ‘backslashreplace’ error handler is
     used on encoding.

   * Each string is limited to 500 characters.

   * Only the filename, the function name and the line number are
     displayed.  (no source code)

   * It is limited to 100 frames and 100 threads.

   * The order is reversed: the most recent call is shown first.

By default, the Python traceback is written to *note sys.stderr: 943.
To see tracebacks, applications must be run in the terminal.  A log file
can alternatively be passed to *note faulthandler.enable(): cc4.

The module is implemented in C, so tracebacks can be dumped on a crash
or when Python is deadlocked.

The *note Python Development Mode: 1f8. calls *note
faulthandler.enable(): cc4. at Python startup.

See also
........

Module *note pdb: a5.

     Interactive source code debugger for Python programs.

Module *note traceback: fe.

     Standard interface to extract, format and print stack traces of
     Python programs.

* Menu:

* Dumping the traceback::
* Fault handler state::
* Dumping the tracebacks after a timeout::
* Dumping the traceback on a user signal::
* Issue with file descriptors::
* Example: Example<13>.


File: python.info,  Node: Dumping the traceback,  Next: Fault handler state,  Up: faulthandler — Dump the Python traceback

5.27.3.1 Dumping the traceback
..............................

 -- Function: faulthandler.dump_traceback (file=sys.stderr,
          all_threads=True)

     Dump the tracebacks of all threads into 'file'.  If 'all_threads'
     is ‘False’, dump only the current thread.

     See also
     ........

     *note traceback.print_tb(): eb9, which can be used to print a
     traceback object.

     Changed in version 3.5: Added support for passing file descriptor
     to this function.


File: python.info,  Node: Fault handler state,  Next: Dumping the tracebacks after a timeout,  Prev: Dumping the traceback,  Up: faulthandler — Dump the Python traceback

5.27.3.2 Fault handler state
............................

 -- Function: faulthandler.enable (file=sys.stderr, all_threads=True)

     Enable the fault handler: install handlers for the *note SIGSEGV:
     10be, *note SIGFPE: 10bf, *note SIGABRT: 10c0, *note SIGBUS: 10c1.
     and *note SIGILL: 10c2. signals to dump the Python traceback.  If
     'all_threads' is ‘True’, produce tracebacks for every running
     thread.  Otherwise, dump only the current thread.

     The 'file' must be kept open until the fault handler is disabled:
     see *note issue with file descriptors: 447e.

     Changed in version 3.5: Added support for passing file descriptor
     to this function.

     Changed in version 3.6: On Windows, a handler for Windows exception
     is also installed.

     Changed in version 3.10: The dump now mentions if a garbage
     collector collection is running if 'all_threads' is true.

 -- Function: faulthandler.disable ()

     Disable the fault handler: uninstall the signal handlers installed
     by *note enable(): cc4.

 -- Function: faulthandler.is_enabled ()

     Check if the fault handler is enabled.


File: python.info,  Node: Dumping the tracebacks after a timeout,  Next: Dumping the traceback on a user signal,  Prev: Fault handler state,  Up: faulthandler — Dump the Python traceback

5.27.3.3 Dumping the tracebacks after a timeout
...............................................

 -- Function: faulthandler.dump_traceback_later (timeout, repeat=False,
          file=sys.stderr, exit=False)

     Dump the tracebacks of all threads, after a timeout of 'timeout'
     seconds, or every 'timeout' seconds if 'repeat' is ‘True’.  If
     'exit' is ‘True’, call ‘_exit()’ with status=1 after dumping the
     tracebacks.  (Note ‘_exit()’ exits the process immediately, which
     means it doesn’t do any cleanup like flushing file buffers.)  If
     the function is called twice, the new call replaces previous
     parameters and resets the timeout.  The timer has a sub-second
     resolution.

     The 'file' must be kept open until the traceback is dumped or *note
     cancel_dump_traceback_later(): 4482. is called: see *note issue
     with file descriptors: 447e.

     This function is implemented using a watchdog thread.

     Changed in version 3.5: Added support for passing file descriptor
     to this function.

     Changed in version 3.7: This function is now always available.

 -- Function: faulthandler.cancel_dump_traceback_later ()

     Cancel the last call to *note dump_traceback_later(): e31.


File: python.info,  Node: Dumping the traceback on a user signal,  Next: Issue with file descriptors,  Prev: Dumping the tracebacks after a timeout,  Up: faulthandler — Dump the Python traceback

5.27.3.4 Dumping the traceback on a user signal
...............................................

 -- Function: faulthandler.register (signum, file=sys.stderr,
          all_threads=True, chain=False)

     Register a user signal: install a handler for the 'signum' signal
     to dump the traceback of all threads, or of the current thread if
     'all_threads' is ‘False’, into 'file'.  Call the previous handler
     if chain is ‘True’.

     The 'file' must be kept open until the signal is unregistered by
     *note unregister(): 4484.: see *note issue with file descriptors:
     447e.

     Not available on Windows.

     Changed in version 3.5: Added support for passing file descriptor
     to this function.

 -- Function: faulthandler.unregister (signum)

     Unregister a user signal: uninstall the handler of the 'signum'
     signal installed by *note register(): e2f.  Return ‘True’ if the
     signal was registered, ‘False’ otherwise.

     Not available on Windows.


File: python.info,  Node: Issue with file descriptors,  Next: Example<13>,  Prev: Dumping the traceback on a user signal,  Up: faulthandler — Dump the Python traceback

5.27.3.5 Issue with file descriptors
....................................

*note enable(): cc4, *note dump_traceback_later(): e31. and *note
register(): e2f. keep the file descriptor of their 'file' argument.  If
the file is closed and its file descriptor is reused by a new file, or
if *note os.dup2(): b7f. is used to replace the file descriptor, the
traceback will be written into a different file.  Call these functions
again each time that the file is replaced.


File: python.info,  Node: Example<13>,  Prev: Issue with file descriptors,  Up: faulthandler — Dump the Python traceback

5.27.3.6 Example
................

Example of a segmentation fault on Linux with and without enabling the
fault handler:

     $ python -c "import ctypes; ctypes.string_at(0)"
     Segmentation fault

     $ python -q -X faulthandler
     >>> import ctypes
     >>> ctypes.string_at(0)
     Fatal Python error: Segmentation fault

     Current thread 0x00007fb899f39700 (most recent call first):
       File "/home/python/cpython/Lib/ctypes/__init__.py", line 486 in string_at
       File "<stdin>", line 1 in <module>
     Segmentation fault


File: python.info,  Node: pdb — The Python Debugger,  Next: The Python Profilers,  Prev: faulthandler — Dump the Python traceback,  Up: Debugging and Profiling

5.27.4 ‘pdb’ — The Python Debugger
----------------------------------

'Source code:' Lib/pdb.py(1)

__________________________________________________________________

The module ‘pdb’ defines an interactive source code debugger for Python
programs.  It supports setting (conditional) breakpoints and single
stepping at the source line level, inspection of stack frames, source
code listing, and evaluation of arbitrary Python code in the context of
any stack frame.  It also supports post-mortem debugging and can be
called under program control.

The debugger is extensible – it is actually defined as the class *note
Pdb: 92b.  This is currently undocumented but easily understood by
reading the source.  The extension interface uses the modules *note bdb:
f. and *note cmd: 19.

See also
........

Module *note faulthandler: 58.

     Used to dump Python tracebacks explicitly, on a fault, after a
     timeout, or on a user signal.

Module *note traceback: fe.

     Standard interface to extract, format and print stack traces of
     Python programs.

The typical usage to break into the debugger is to insert:

     import pdb; pdb.set_trace()

Or:

     breakpoint()

at the location you want to break into the debugger, and then run the
program.  You can then step through the code following this statement,
and continue running without the debugger using the *note continue:
448b. command.

Changed in version 3.7: The built-in *note breakpoint(): 234, when
called with defaults, can be used instead of ‘import pdb;
pdb.set_trace()’.

     def double(x):
        breakpoint()
        return x * 2
     val = 3
     print(f"{val} * 2 is {double(val)}")

The debugger’s prompt is ‘(Pdb)’, which is the indicator that you are in
debug mode:

     > ...(2)double()
     -> breakpoint()
     (Pdb) p x
     3
     (Pdb) continue
     3 * 2 is 6

Changed in version 3.3: Tab-completion via the *note readline: ba.
module is available for commands and command arguments, e.g.  the
current global and local names are offered as arguments of the ‘p’
command.

* Menu:

* Command-line interface: Command-line interface<6>.
* Debugger commands::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pdb.py


File: python.info,  Node: Command-line interface<6>,  Next: Debugger commands,  Up: pdb — The Python Debugger

5.27.4.1 Command-line interface
...............................

You can also invoke ‘pdb’ from the command line to debug other scripts.
For example:

     python -m pdb [-c command] (-m module | pyfile) [args ...]

When invoked as a module, pdb will automatically enter post-mortem
debugging if the program being debugged exits abnormally.  After
post-mortem debugging (or after normal exit of the program), pdb will
restart the program.  Automatic restarting preserves pdb’s state (such
as breakpoints) and in most cases is more useful than quitting the
debugger upon program’s exit.

 -- Option: -c, --command <command>

     To execute commands as if given in a ‘.pdbrc’ file; see *note
     Debugger commands: 4490.

     Changed in version 3.2: Added the ‘-c’ option.

 -- Option: -m <module>

     To execute modules similar to the way ‘python -m’ does.  As with a
     script, the debugger will pause execution just before the first
     line of the module.

     Changed in version 3.7: Added the ‘-m’ option.

Typical usage to execute a statement under control of the debugger is:

     >>> import pdb
     >>> def f(x):
     ...     print(1 / x)
     >>> pdb.run("f(2)")
     > <string>(1)<module>()
     (Pdb) continue
     0.5
     >>>

The typical usage to inspect a crashed program is:

     >>> import pdb
     >>> def f(x):
     ...     print(1 / x)
     ...
     >>> f(0)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
       File "<stdin>", line 2, in f
     ZeroDivisionError: division by zero
     >>> pdb.pm()
     > <stdin>(2)f()
     (Pdb) p x
     0
     (Pdb)

Changed in version 3.13: The implementation of PEP 667(1) means that
name assignments made via ‘pdb’ will immediately affect the active
scope, even when running inside an *note optimized scope: 17e.

The module defines the following functions; each enters the debugger in
a slightly different way:

 -- Function: pdb.run (statement, globals=None, locals=None)

     Execute the 'statement' (given as a string or a code object) under
     debugger control.  The debugger prompt appears before any code is
     executed; you can set breakpoints and type *note continue: 448b, or
     you can step through the statement using *note step: 4492. or *note
     next: 4493. (all these commands are explained below).  The optional
     'globals' and 'locals' arguments specify the environment in which
     the code is executed; by default the dictionary of the module *note
     __main__: 1. is used.  (See the explanation of the built-in *note
     exec(): 17f. or *note eval(): 180. functions.)

 -- Function: pdb.runeval (expression, globals=None, locals=None)

     Evaluate the 'expression' (given as a string or a code object)
     under debugger control.  When ‘runeval()’ returns, it returns the
     value of the 'expression'.  Otherwise this function is similar to
     *note run(): 428e.

 -- Function: pdb.runcall (function, *args, **kwds)

     Call the 'function' (a function or method object, not a string)
     with the given arguments.  When ‘runcall()’ returns, it returns
     whatever the function call returned.  The debugger prompt appears
     as soon as the function is entered.

 -- Function: pdb.set_trace (*, header=None)

     Enter the debugger at the calling stack frame.  This is useful to
     hard-code a breakpoint at a given point in a program, even if the
     code is not otherwise being debugged (e.g.  when an assertion
     fails).  If given, 'header' is printed to the console just before
     debugging begins.

     Changed in version 3.7: The keyword-only argument 'header'.

     Changed in version 3.13: ‘set_trace()’ will enter the debugger
     immediately, rather than on the next line of code to be executed.

 -- Function: pdb.post_mortem (t=None)

     Enter post-mortem debugging of the given exception or *note
     traceback object: b0d.  If no value is given, it uses the exception
     that is currently being handled, or raises ‘ValueError’ if there
     isn’t one.

     Changed in version 3.13: Support for exception objects was added.

 -- Function: pdb.pm ()

     Enter post-mortem debugging of the exception found in *note
     sys.last_exc: 4c1.

The ‘run*’ functions and *note set_trace(): 235. are aliases for
instantiating the *note Pdb: 92b. class and calling the method of the
same name.  If you want to access further features, you have to do this
yourself:

 -- Class: pdb.Pdb (completekey='tab', stdin=None, stdout=None,
          skip=None, nosigint=False, readrc=True)

     ‘Pdb’ is the debugger class.

     The 'completekey', 'stdin' and 'stdout' arguments are passed to the
     underlying *note cmd.Cmd: 17d5. class; see the description there.

     The 'skip' argument, if given, must be an iterable of glob-style
     module name patterns.  The debugger will not step into frames that
     originate in a module that matches one of these patterns.  (2)

     By default, Pdb sets a handler for the SIGINT signal (which is sent
     when the user presses ‘Ctrl’-‘C’ on the console) when you give a
     *note continue: 448b. command.  This allows you to break into the
     debugger again by pressing ‘Ctrl’-‘C’.  If you want Pdb not to
     touch the SIGINT handler, set 'nosigint' to true.

     The 'readrc' argument defaults to true and controls whether Pdb
     will load .pdbrc files from the filesystem.

     Example call to enable tracing with 'skip':

          import pdb; pdb.Pdb(skip=['django.*']).set_trace()

     Raises an *note auditing event: 1a15. ‘pdb.Pdb’ with no arguments.

     Changed in version 3.1: Added the 'skip' parameter.

     Changed in version 3.2: Added the 'nosigint' parameter.
     Previously, a SIGINT handler was never set by Pdb.

     Changed in version 3.6: The 'readrc' argument.

      -- Method: run (statement, globals=None, locals=None)
      -- Method: runeval (expression, globals=None, locals=None)
      -- Method: runcall (function, *args, **kwds)
      -- Method: set_trace ()

          See the documentation for the functions explained above.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/

   (2) Whether a frame is considered to originate in a certain module is
determined by the ‘__name__’ in the frame globals.


File: python.info,  Node: Debugger commands,  Prev: Command-line interface<6>,  Up: pdb — The Python Debugger

5.27.4.2 Debugger commands
..........................

The commands recognized by the debugger are listed below.  Most commands
can be abbreviated to one or two letters as indicated; e.g.  ‘h(elp)’
means that either ‘h’ or ‘help’ can be used to enter the help command
(but not ‘he’ or ‘hel’, nor ‘H’ or ‘Help’ or ‘HELP’).  Arguments to
commands must be separated by whitespace (spaces or tabs).  Optional
arguments are enclosed in square brackets (‘[]’) in the command syntax;
the square brackets must not be typed.  Alternatives in the command
syntax are separated by a vertical bar (‘|’).

Entering a blank line repeats the last command entered.  Exception: if
the last command was a *note list: 449b. command, the next 11 lines are
listed.

Commands that the debugger doesn’t recognize are assumed to be Python
statements and are executed in the context of the program being
debugged.  Python statements can also be prefixed with an exclamation
point (‘!’).  This is a powerful way to inspect the program being
debugged; it is even possible to change a variable or call a function.
When an exception occurs in such a statement, the exception name is
printed but the debugger’s state is not changed.

Changed in version 3.13: Expressions/Statements whose prefix is a pdb
command are now correctly identified and executed.

The debugger supports *note aliases: 449c.  Aliases can have parameters
which allows one a certain level of adaptability to the context under
examination.

Multiple commands may be entered on a single line, separated by ‘;;’.
(A single ‘;’ is not used as it is the separator for multiple commands
in a line that is passed to the Python parser.)  No intelligence is
applied to separating the commands; the input is split at the first ‘;;’
pair, even if it is in the middle of a quoted string.  A workaround for
strings with double semicolons is to use implicit string concatenation
‘';'';'’ or ‘";"";"’.

To set a temporary global variable, use a 'convenience variable'.  A
'convenience variable' is a variable whose name starts with ‘$’.  For
example, ‘$foo = 1’ sets a global variable ‘$foo’ which you can use in
the debugger session.  The 'convenience variables' are cleared when the
program resumes execution so it’s less likely to interfere with your
program compared to using normal variables like ‘foo = 1’.

There are three preset 'convenience variables':

   * ‘$_frame’: the current frame you are debugging

   * ‘$_retval’: the return value if the frame is returning

   * ‘$_exception’: the exception if the frame is raising an exception

Added in version 3.12: Added the 'convenience variable' feature.

If a file ‘.pdbrc’ exists in the user’s home directory or in the current
directory, it is read with ‘'utf-8'’ encoding and executed as if it had
been typed at the debugger prompt, with the exception that empty lines
and lines starting with ‘#’ are ignored.  This is particularly useful
for aliases.  If both files exist, the one in the home directory is read
first and aliases defined there can be overridden by the local file.

Changed in version 3.2: ‘.pdbrc’ can now contain commands that continue
debugging, such as *note continue: 448b. or *note next: 4493.
Previously, these commands had no effect.

Changed in version 3.11: ‘.pdbrc’ is now read with ‘'utf-8'’ encoding.
Previously, it was read with the system locale encoding.

 -- Pdbcommand: h(elp) [command]

     Without argument, print the list of available commands.  With a
     'command' as argument, print help about that command.  ‘help pdb’
     displays the full documentation (the docstring of the ‘pdb’
     module).  Since the 'command' argument must be an identifier, ‘help
     exec’ must be entered to get help on the ‘!’ command.

 -- Pdbcommand: w(here)

     Print a stack trace, with the most recent frame at the bottom.  An
     arrow (‘>’) indicates the current frame, which determines the
     context of most commands.

 -- Pdbcommand: d(own) [count]

     Move the current frame 'count' (default one) levels down in the
     stack trace (to a newer frame).

 -- Pdbcommand: u(p) [count]

     Move the current frame 'count' (default one) levels up in the stack
     trace (to an older frame).

 -- Pdbcommand: b(reak) [([filename:]lineno | function) [, condition]]

     With a 'lineno' argument, set a break at line 'lineno' in the
     current file.  The line number may be prefixed with a 'filename'
     and a colon, to specify a breakpoint in another file (possibly one
     that hasn’t been loaded yet).  The file is searched on *note
     sys.path: 3b7.  Accepatable forms of 'filename' are
     ‘/abspath/to/file.py’, ‘relpath/file.py’, ‘module’ and
     ‘package.module’.

     With a 'function' argument, set a break at the first executable
     statement within that function.  'function' can be any expression
     that evaluates to a function in the current namespace.

     If a second argument is present, it is an expression which must
     evaluate to true before the breakpoint is honored.

     Without argument, list all breaks, including for each breakpoint,
     the number of times that breakpoint has been hit, the current
     ignore count, and the associated condition if any.

     Each breakpoint is assigned a number to which all the other
     breakpoint commands refer.

 -- Pdbcommand: tbreak [([filename:]lineno | function) [, condition]]

     Temporary breakpoint, which is removed automatically when it is
     first hit.  The arguments are the same as for *note break: 44a1.

 -- Pdbcommand: cl(ear) [filename:lineno | bpnumber ...]

     With a 'filename:lineno' argument, clear all the breakpoints at
     this line.  With a space separated list of breakpoint numbers,
     clear those breakpoints.  Without argument, clear all breaks (but
     first ask confirmation).

 -- Pdbcommand: disable bpnumber [bpnumber ...]

     Disable the breakpoints given as a space separated list of
     breakpoint numbers.  Disabling a breakpoint means it cannot cause
     the program to stop execution, but unlike clearing a breakpoint, it
     remains in the list of breakpoints and can be (re-)enabled.

 -- Pdbcommand: enable bpnumber [bpnumber ...]

     Enable the breakpoints specified.

 -- Pdbcommand: ignore bpnumber [count]

     Set the ignore count for the given breakpoint number.  If 'count'
     is omitted, the ignore count is set to 0.  A breakpoint becomes
     active when the ignore count is zero.  When non-zero, the 'count'
     is decremented each time the breakpoint is reached and the
     breakpoint is not disabled and any associated condition evaluates
     to true.

 -- Pdbcommand: condition bpnumber [condition]

     Set a new 'condition' for the breakpoint, an expression which must
     evaluate to true before the breakpoint is honored.  If 'condition'
     is absent, any existing condition is removed; i.e., the breakpoint
     is made unconditional.

 -- Pdbcommand: commands [bpnumber]

     Specify a list of commands for breakpoint number 'bpnumber'.  The
     commands themselves appear on the following lines.  Type a line
     containing just ‘end’ to terminate the commands.  An example:

          (Pdb) commands 1
          (com) p some_variable
          (com) end
          (Pdb)

     To remove all commands from a breakpoint, type ‘commands’ and
     follow it immediately with ‘end’; that is, give no commands.

     With no 'bpnumber' argument, ‘commands’ refers to the last
     breakpoint set.

     You can use breakpoint commands to start your program up again.
     Simply use the *note continue: 448b. command, or *note step: 4492,
     or any other command that resumes execution.

     Specifying any command resuming execution (currently *note
     continue: 448b, *note step: 4492, *note next: 4493, *note return:
     44a9, *note jump: 44aa, *note quit: 44ab. and their abbreviations)
     terminates the command list (as if that command was immediately
     followed by end).  This is because any time you resume execution
     (even with a simple next or step), you may encounter another
     breakpoint—which could have its own command list, leading to
     ambiguities about which list to execute.

     If you use the ‘silent’ command in the command list, the usual
     message about stopping at a breakpoint is not printed.  This may be
     desirable for breakpoints that are to print a specific message and
     then continue.  If none of the other commands print anything, you
     see no sign that the breakpoint was reached.

 -- Pdbcommand: s(tep)

     Execute the current line, stop at the first possible occasion
     (either in a function that is called or on the next line in the
     current function).

 -- Pdbcommand: n(ext)

     Continue execution until the next line in the current function is
     reached or it returns.  (The difference between *note next: 4493.
     and *note step: 4492. is that ‘step’ stops inside a called
     function, while ‘next’ executes called functions at (nearly) full
     speed, only stopping at the next line in the current function.)

 -- Pdbcommand: unt(il) [lineno]

     Without argument, continue execution until the line with a number
     greater than the current one is reached.

     With 'lineno', continue execution until a line with a number
     greater or equal to 'lineno' is reached.  In both cases, also stop
     when the current frame returns.

     Changed in version 3.2: Allow giving an explicit line number.

 -- Pdbcommand: r(eturn)

     Continue execution until the current function returns.

 -- Pdbcommand: c(ont(inue))

     Continue execution, only stop when a breakpoint is encountered.

 -- Pdbcommand: j(ump) lineno

     Set the next line that will be executed.  Only available in the
     bottom-most frame.  This lets you jump back and execute code again,
     or jump forward to skip code that you don’t want to run.

     It should be noted that not all jumps are allowed – for instance it
     is not possible to jump into the middle of a *note for: 2f2. loop
     or out of a *note finally: 9d5. clause.

 -- Pdbcommand: l(ist) [first[, last]]

     List source code for the current file.  Without arguments, list 11
     lines around the current line or continue the previous listing.
     With ‘.’ as argument, list 11 lines around the current line.  With
     one argument, list 11 lines around at that line.  With two
     arguments, list the given range; if the second argument is less
     than the first, it is interpreted as a count.

     The current line in the current frame is indicated by ‘->’.  If an
     exception is being debugged, the line where the exception was
     originally raised or propagated is indicated by ‘>>’, if it differs
     from the current line.

     Changed in version 3.2: Added the ‘>>’ marker.

 -- Pdbcommand: ll | longlist

     List all source code for the current function or frame.
     Interesting lines are marked as for *note list: 449b.

     Added in version 3.2.

 -- Pdbcommand: a(rgs)

     Print the arguments of the current function and their current
     values.

 -- Pdbcommand: p expression

     Evaluate 'expression' in the current context and print its value.

          Note: ‘print()’ can also be used, but is not a debugger
          command — this executes the Python *note print(): fae.
          function.

 -- Pdbcommand: pp expression

     Like the *note p: faf. command, except the value of 'expression' is
     pretty-printed using the *note pprint: ae. module.

 -- Pdbcommand: whatis expression

     Print the type of 'expression'.

 -- Pdbcommand: source expression

     Try to get source code of 'expression' and display it.

     Added in version 3.2.

 -- Pdbcommand: display [expression]

     Display the value of 'expression' if it changed, each time
     execution stops in the current frame.

     Without 'expression', list all display expressions for the current
     frame.

          Note: Display evaluates 'expression' and compares to the
          result of the previous evaluation of 'expression', so when the
          result is mutable, display may not be able to pick up the
          changes.

     Example:

          lst = []
          breakpoint()
          pass
          lst.append(1)
          print(lst)

     Display won’t realize ‘lst’ has been changed because the result of
     evaluation is modified in place by ‘lst.append(1)’ before being
     compared:

          > example.py(3)<module>()
          -> pass
          (Pdb) display lst
          display lst: []
          (Pdb) n
          > example.py(4)<module>()
          -> lst.append(1)
          (Pdb) n
          > example.py(5)<module>()
          -> print(lst)
          (Pdb)

     You can do some tricks with copy mechanism to make it work:

          > example.py(3)<module>()
          -> pass
          (Pdb) display lst[:]
          display lst[:]: []
          (Pdb) n
          > example.py(4)<module>()
          -> lst.append(1)
          (Pdb) n
          > example.py(5)<module>()
          -> print(lst)
          display lst[:]: [1]  [old: []]
          (Pdb)

     Added in version 3.2.

 -- Pdbcommand: undisplay [expression]

     Do not display 'expression' anymore in the current frame.  Without
     'expression', clear all display expressions for the current frame.

     Added in version 3.2.

 -- Pdbcommand: interact

     Start an interactive interpreter (using the *note code: 1a. module)
     in a new global namespace initialised from the local and global
     namespaces for the current scope.  Use ‘exit()’ or ‘quit()’ to exit
     the interpreter and return to the debugger.

          Note: As ‘interact’ creates a new dedicated namespace for code
          execution, assignments to variables will not affect the
          original namespaces.  However, modifications to any referenced
          mutable objects will be reflected in the original namespaces
          as usual.

     Added in version 3.2.

     Changed in version 3.13: ‘exit()’ and ‘quit()’ can be used to exit
     the *note interact: 44b4. command.

     Changed in version 3.13: *note interact: 44b4. directs its output
     to the debugger’s output channel rather than *note sys.stderr: 943.

 -- Pdbcommand: alias [name [command]]

     Create an alias called 'name' that executes 'command'.  The
     'command' must 'not' be enclosed in quotes.  Replaceable parameters
     can be indicated by ‘%1’, ‘%2’, … and ‘%9’, while ‘%*’ is replaced
     by all the parameters.  If 'command' is omitted, the current alias
     for 'name' is shown.  If no arguments are given, all aliases are
     listed.

     Aliases may be nested and can contain anything that can be legally
     typed at the pdb prompt.  Note that internal pdb commands 'can' be
     overridden by aliases.  Such a command is then hidden until the
     alias is removed.  Aliasing is recursively applied to the first
     word of the command line; all other words in the line are left
     alone.

     As an example, here are two useful aliases (especially when placed
     in the ‘.pdbrc’ file):

          # Print instance variables (usage "pi classInst")
          alias pi for k in %1.__dict__.keys(): print(f"%1.{k} = {%1.__dict__[k]}")
          # Print instance variables in self
          alias ps pi self

 -- Pdbcommand: unalias name

     Delete the specified alias 'name'.

 -- Pdbcommand: ! statement

     Execute the (one-line) 'statement' in the context of the current
     stack frame.  The exclamation point can be omitted unless the first
     word of the statement resembles a debugger command, e.g.:

          (Pdb) ! n=42
          (Pdb)

     To set a global variable, you can prefix the assignment command
     with a *note global: 18a. statement on the same line, e.g.:

          (Pdb) global list_options; list_options = ['-l']
          (Pdb)

 -- Pdbcommand: run [args ...]
 -- Pdbcommand: restart [args ...]

     Restart the debugged Python program.  If 'args' is supplied, it is
     split with *note shlex: c4. and the result is used as the new *note
     sys.argv: 12ab.  History, breakpoints, actions and debugger options
     are preserved.  *note restart: 44b9. is an alias for *note run:
     44b8.

 -- Pdbcommand: q(uit)

     Quit from the debugger.  The program being executed is aborted.

 -- Pdbcommand: debug code

     Enter a recursive debugger that steps through 'code' (which is an
     arbitrary expression or statement to be executed in the current
     environment).

 -- Pdbcommand: retval

     Print the return value for the last return of the current function.

 -- Pdbcommand: exceptions [excnumber]

     List or jump between chained exceptions.

     When using ‘pdb.pm()’ or ‘Pdb.post_mortem(...)’ with a chained
     exception instead of a traceback, it allows the user to move
     between the chained exceptions using ‘exceptions’ command to list
     exceptions, and ‘exceptions <number>’ to switch to that exception.

     Example:

          def out():
              try:
                  middle()
              except Exception as e:
                  raise ValueError("reraise middle() error") from e

          def middle():
              try:
                  return inner(0)
              except Exception as e:
                  raise ValueError("Middle fail")

          def inner(x):
              1 / x

           out()

     calling ‘pdb.pm()’ will allow to move between exceptions:

          > example.py(5)out()
          -> raise ValueError("reraise middle() error") from e

          (Pdb) exceptions
            0 ZeroDivisionError('division by zero')
            1 ValueError('Middle fail')
          > 2 ValueError('reraise middle() error')

          (Pdb) exceptions 0
          > example.py(16)inner()
          -> 1 / x

          (Pdb) up
          > example.py(10)middle()
          -> return inner(0)

     Added in version 3.13.


File: python.info,  Node: The Python Profilers,  Next: timeit — Measure execution time of small code snippets,  Prev: pdb — The Python Debugger,  Up: Debugging and Profiling

5.27.5 The Python Profilers
---------------------------

'Source code:' Lib/profile.py(1) and Lib/pstats.py(2)

__________________________________________________________________

* Menu:

* Introduction to the profilers::
* Instant User’s Manual::
* profile and cProfile Module Reference::
* The Stats Class::
* What Is Deterministic Profiling?::
* Limitations::
* Calibration::
* Using a custom timer::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/profile.py

   (2) https://github.com/python/cpython/tree/3.13/Lib/pstats.py


File: python.info,  Node: Introduction to the profilers,  Next: Instant User’s Manual,  Up: The Python Profilers

5.27.5.1 Introduction to the profilers
......................................

*note cProfile: 27. and *note profile: af. provide 'deterministic
profiling' of Python programs.  A 'profile' is a set of statistics that
describes how often and for how long various parts of the program
executed.  These statistics can be formatted into reports via the *note
pstats: b0. module.

The Python standard library provides two different implementations of
the same profiling interface:

  1. *note cProfile: 27. is recommended for most users; it’s a C
     extension with reasonable overhead that makes it suitable for
     profiling long-running programs.  Based on ‘lsprof’, contributed by
     Brett Rosen and Ted Czotter.

  2. *note profile: af, a pure Python module whose interface is imitated
     by *note cProfile: 27, but which adds significant overhead to
     profiled programs.  If you’re trying to extend the profiler in some
     way, the task might be easier with this module.  Originally
     designed and written by Jim Roskind.

     Note: The profiler modules are designed to provide an execution
     profile for a given program, not for benchmarking purposes (for
     that, there is *note timeit: ef. for reasonably accurate results).
     This particularly applies to benchmarking Python code against C
     code: the profilers introduce overhead for Python code, but not for
     C-level functions, and so the C code would seem faster than any
     Python one.


File: python.info,  Node: Instant User’s Manual,  Next: profile and cProfile Module Reference,  Prev: Introduction to the profilers,  Up: The Python Profilers

5.27.5.2 Instant User’s Manual
..............................

This section is provided for users that “don’t want to read the manual.”
It provides a very brief overview, and allows a user to rapidly perform
profiling on an existing application.

To profile a function that takes a single argument, you can do:

     import cProfile
     import re
     cProfile.run('re.compile("foo|bar")')

(Use *note profile: af. instead of *note cProfile: 27. if the latter is
not available on your system.)

The above action would run *note re.compile(): bf4. and print profile
results like the following:

           214 function calls (207 primitive calls) in 0.002 seconds

     Ordered by: cumulative time

     ncalls  tottime  percall  cumtime  percall filename:lineno(function)
          1    0.000    0.000    0.002    0.002 {built-in method builtins.exec}
          1    0.000    0.000    0.001    0.001 <string>:1(<module>)
          1    0.000    0.000    0.001    0.001 __init__.py:250(compile)
          1    0.000    0.000    0.001    0.001 __init__.py:289(_compile)
          1    0.000    0.000    0.000    0.000 _compiler.py:759(compile)
          1    0.000    0.000    0.000    0.000 _parser.py:937(parse)
          1    0.000    0.000    0.000    0.000 _compiler.py:598(_code)
          1    0.000    0.000    0.000    0.000 _parser.py:435(_parse_sub)

The first line indicates that 214 calls were monitored.  Of those calls,
207 were 'primitive', meaning that the call was not induced via
recursion.  The next line: ‘Ordered by: cumulative time’ indicates the
output is sorted by the ‘cumtime’ values.  The column headings include:

ncalls

     for the number of calls.

tottime

     for the total time spent in the given function (and excluding time
     made in calls to sub-functions)

percall

     is the quotient of ‘tottime’ divided by ‘ncalls’

cumtime

     is the cumulative time spent in this and all subfunctions (from
     invocation till exit).  This figure is accurate 'even' for
     recursive functions.

percall

     is the quotient of ‘cumtime’ divided by primitive calls

filename:lineno(function)

     provides the respective data of each function

When there are two numbers in the first column (for example ‘3/1’), it
means that the function recursed.  The second value is the number of
primitive calls and the former is the total number of calls.  Note that
when the function does not recurse, these two values are the same, and
only the single figure is printed.

Instead of printing the output at the end of the profile run, you can
save the results to a file by specifying a filename to the ‘run()’
function:

     import cProfile
     import re
     cProfile.run('re.compile("foo|bar")', 'restats')

The *note pstats.Stats: 44c4. class reads profile results from a file
and formats them in various ways.  The files *note cProfile: 27. and
*note profile: af. can also be invoked as a script to profile another
script.  For example:

     python -m cProfile [-o output_file] [-s sort_order] (-m module | myscript.py)

 -- Option: -o <output_file>

     Writes the profile results to a file instead of to stdout.

 -- Option: -s <sort_order>

     Specifies one of the *note sort_stats(): 44c8. sort values to sort
     the output by.  This only applies when *note -o: 44c6. is not
     supplied.

 -- Option: -m <module>

     Specifies that a module is being profiled instead of a script.

     Added in version 3.7: Added the ‘-m’ option to *note cProfile: 27.

     Added in version 3.8: Added the ‘-m’ option to *note profile: af.

The *note pstats: b0. module’s *note Stats: 44c4. class has a variety of
methods for manipulating and printing the data saved into a profile
results file:

     import pstats
     from pstats import SortKey
     p = pstats.Stats('restats')
     p.strip_dirs().sort_stats(-1).print_stats()

The *note strip_dirs(): 44ca. method removed the extraneous path from
all the module names.  The *note sort_stats(): 44c8. method sorted all
the entries according to the standard module/line/name string that is
printed.  The *note print_stats(): 44cb. method printed out all the
statistics.  You might try the following sort calls:

     p.sort_stats(SortKey.NAME)
     p.print_stats()

The first call will actually sort the list by function name, and the
second call will print out the statistics.  The following are some
interesting calls to experiment with:

     p.sort_stats(SortKey.CUMULATIVE).print_stats(10)

This sorts the profile by cumulative time in a function, and then only
prints the ten most significant lines.  If you want to understand what
algorithms are taking time, the above line is what you would use.

If you were looking to see what functions were looping a lot, and taking
a lot of time, you would do:

     p.sort_stats(SortKey.TIME).print_stats(10)

to sort according to time spent within each function, and then print the
statistics for the top ten functions.

You might also try:

     p.sort_stats(SortKey.FILENAME).print_stats('__init__')

This will sort all the statistics by file name, and then print out
statistics for only the class init methods (since they are spelled with
‘__init__’ in them).  As one final example, you could try:

     p.sort_stats(SortKey.TIME, SortKey.CUMULATIVE).print_stats(.5, 'init')

This line sorts statistics with a primary key of time, and a secondary
key of cumulative time, and then prints out some of the statistics.  To
be specific, the list is first culled down to 50% (re: ‘.5’) of its
original size, then only lines containing ‘init’ are maintained, and
that sub-sub-list is printed.

If you wondered what functions called the above functions, you could now
(‘p’ is still sorted according to the last criteria) do:

     p.print_callers(.5, 'init')

and you would get a list of callers for each of the listed functions.

If you want more functionality, you’re going to have to read the manual,
or guess what the following functions do:

     p.print_callees()
     p.add('restats')

Invoked as a script, the *note pstats: b0. module is a statistics
browser for reading and examining profile dumps.  It has a simple
line-oriented interface (implemented using *note cmd: 19.) and
interactive help.


File: python.info,  Node: profile and cProfile Module Reference,  Next: The Stats Class,  Prev: Instant User’s Manual,  Up: The Python Profilers

5.27.5.3 ‘profile’ and ‘cProfile’ Module Reference
..................................................

Both the *note profile: af. and ‘cProfile’ modules provide the following
functions:

 -- Function: profile.run (command, filename=None, sort=-1)

     This function takes a single argument that can be passed to the
     *note exec(): 17f. function, and an optional file name.  In all
     cases this routine executes:

          exec(command, __main__.__dict__, __main__.__dict__)

     and gathers profiling statistics from the execution.  If no file
     name is present, then this function automatically creates a *note
     Stats: 44c4. instance and prints a simple profiling report.  If the
     sort value is specified, it is passed to this ‘Stats’ instance to
     control how the results are sorted.

 -- Function: profile.runctx (command, globals, locals, filename=None,
          sort=-1)

     This function is similar to *note run(): 44cd, with added arguments
     to supply the globals and locals mappings for the 'command' string.
     This routine executes:

          exec(command, globals, locals)

     and gathers profiling statistics as in the *note run(): 44cd.
     function above.

 -- Class: profile.Profile (timer=None, timeunit=0.0, subcalls=True,
          builtins=True)

     This class is normally only used if more precise control over
     profiling is needed than what the ‘cProfile.run()’ function
     provides.

     A custom timer can be supplied for measuring how long code takes to
     run via the 'timer' argument.  This must be a function that returns
     a single number representing the current time.  If the number is an
     integer, the 'timeunit' specifies a multiplier that specifies the
     duration of each unit of time.  For example, if the timer returns
     times measured in thousands of seconds, the time unit would be
     ‘.001’.

     Directly using the ‘Profile’ class allows formatting profile
     results without writing the profile data to a file:

          import cProfile, pstats, io
          from pstats import SortKey
          pr = cProfile.Profile()
          pr.enable()
          # ... do something ...
          pr.disable()
          s = io.StringIO()
          sortby = SortKey.CUMULATIVE
          ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
          ps.print_stats()
          print(s.getvalue())

     The ‘Profile’ class can also be used as a context manager
     (supported only in ‘cProfile’ module.  see *note Context Manager
     Types: 2171.):

          import cProfile

          with cProfile.Profile() as pr:
              # ... do something ...

              pr.print_stats()

     Changed in version 3.8: Added context manager support.

      -- Method: enable ()

          Start collecting profiling data.  Only in ‘cProfile’.

      -- Method: disable ()

          Stop collecting profiling data.  Only in ‘cProfile’.

      -- Method: create_stats ()

          Stop collecting profiling data and record the results
          internally as the current profile.

      -- Method: print_stats (sort=-1)

          Create a *note Stats: 44c4. object based on the current
          profile and print the results to stdout.

          The 'sort' parameter specifies the sorting order of the
          displayed statistics.  It accepts a single key or a tuple of
          keys to enable multi-level sorting, as in *note
          Stats.sort_stats: 44c8.

          Added in version 3.13: ‘print_stats()’ now accepts a tuple of
          keys.

      -- Method: dump_stats (filename)

          Write the results of the current profile to 'filename'.

      -- Method: run (cmd)

          Profile the cmd via *note exec(): 17f.

      -- Method: runctx (cmd, globals, locals)

          Profile the cmd via *note exec(): 17f. with the specified
          global and local environment.

      -- Method: runcall (func, /, *args, **kwargs)

          Profile ‘func(*args, **kwargs)’

Note that profiling will only work if the called command/function
actually returns.  If the interpreter is terminated (e.g.  via a *note
sys.exit(): 1394. call during the called command/function execution) no
profiling results will be printed.


File: python.info,  Node: The Stats Class,  Next: What Is Deterministic Profiling?,  Prev: profile and cProfile Module Reference,  Up: The Python Profilers

5.27.5.4 The ‘Stats’ Class
..........................

Analysis of the profiler data is done using the *note Stats: 44c4.
class.

 -- Class: pstats.Stats (*filenames or profile, stream=sys.stdout)

     This class constructor creates an instance of a “statistics object”
     from a 'filename' (or list of filenames) or from a ‘Profile’
     instance.  Output will be printed to the stream specified by
     'stream'.

     The file selected by the above constructor must have been created
     by the corresponding version of *note profile: af. or *note
     cProfile: 27.  To be specific, there is 'no' file compatibility
     guaranteed with future versions of this profiler, and there is no
     compatibility with files produced by other profilers, or the same
     profiler run on a different operating system.  If several files are
     provided, all the statistics for identical functions will be
     coalesced, so that an overall view of several processes can be
     considered in a single report.  If additional files need to be
     combined with data in an existing *note Stats: 44c4. object, the
     *note add(): 44d8. method can be used.

     Instead of reading the profile data from a file, a
     ‘cProfile.Profile’ or *note profile.Profile: 9ee. object can be
     used as the profile data source.

     ‘Stats’ objects have the following methods:

      -- Method: strip_dirs ()

          This method for the ‘Stats’ class removes all leading path
          information from file names.  It is very useful in reducing
          the size of the printout to fit within (close to) 80 columns.
          This method modifies the object, and the stripped information
          is lost.  After performing a strip operation, the object is
          considered to have its entries in a “random” order, as it was
          just after object initialization and loading.  If *note
          strip_dirs(): 44ca. causes two function names to be
          indistinguishable (they are on the same line of the same
          filename, and have the same function name), then the
          statistics for these two entries are accumulated into a single
          entry.

      -- Method: add (*filenames)

          This method of the ‘Stats’ class accumulates additional
          profiling information into the current profiling object.  Its
          arguments should refer to filenames created by the
          corresponding version of *note profile.run(): 44cd. or
          ‘cProfile.run()’.  Statistics for identically named (re: file,
          line, name) functions are automatically accumulated into
          single function statistics.

      -- Method: dump_stats (filename)

          Save the data loaded into the ‘Stats’ object to a file named
          'filename'.  The file is created if it does not exist, and is
          overwritten if it already exists.  This is equivalent to the
          method of the same name on the *note profile.Profile: 9ee. and
          ‘cProfile.Profile’ classes.

      -- Method: sort_stats (*keys)

          This method modifies the ‘Stats’ object by sorting it
          according to the supplied criteria.  The argument can be
          either a string or a SortKey enum identifying the basis of a
          sort (example: ‘'time'’, ‘'name'’, ‘SortKey.TIME’ or
          ‘SortKey.NAME’).  The SortKey enums argument have advantage
          over the string argument in that it is more robust and less
          error prone.

          When more than one key is provided, then additional keys are
          used as secondary criteria when there is equality in all keys
          selected before them.  For example, ‘sort_stats(SortKey.NAME,
          SortKey.FILE)’ will sort all the entries according to their
          function name, and resolve all ties (identical function names)
          by sorting by file name.

          For the string argument, abbreviations can be used for any key
          names, as long as the abbreviation is unambiguous.

          The following are the valid string and SortKey:

          Valid String Arg       Valid enum Arg            Meaning
                                                           
          ----------------------------------------------------------------------------
                                                           
          ‘'calls'’              SortKey.CALLS             call count
                                                           
                                                           
          ‘'cumulative'’         SortKey.CUMULATIVE        cumulative time
                                                           
                                                           
          ‘'cumtime'’            N/A                       cumulative time
                                                           
                                                           
          ‘'file'’               N/A                       file name
                                                           
                                                           
          ‘'filename'’           SortKey.FILENAME          file name
                                                           
                                                           
          ‘'module'’             N/A                       file name
                                                           
                                                           
          ‘'ncalls'’             N/A                       call count
                                                           
                                                           
          ‘'pcalls'’             SortKey.PCALLS            primitive call count
                                                           
                                                           
          ‘'line'’               SortKey.LINE              line number
                                                           
                                                           
          ‘'name'’               SortKey.NAME              function name
                                                           
                                                           
          ‘'nfl'’                SortKey.NFL               name/file/line
                                                           
                                                           
          ‘'stdname'’            SortKey.STDNAME           standard name
                                                           
                                                           
          ‘'time'’               SortKey.TIME              internal time
                                                           
                                                           
          ‘'tottime'’            N/A                       internal time
                                                           

          Note that all sorts on statistics are in descending order
          (placing most time consuming items first), where as name,
          file, and line number searches are in ascending order
          (alphabetical).  The subtle distinction between ‘SortKey.NFL’
          and ‘SortKey.STDNAME’ is that the standard name is a sort of
          the name as printed, which means that the embedded line
          numbers get compared in an odd way.  For example, lines 3, 20,
          and 40 would (if the file names were the same) appear in the
          string order 20, 3 and 40.  In contrast, ‘SortKey.NFL’ does a
          numeric compare of the line numbers.  In fact,
          ‘sort_stats(SortKey.NFL)’ is the same as
          ‘sort_stats(SortKey.NAME, SortKey.FILENAME, SortKey.LINE)’.

          For backward-compatibility reasons, the numeric arguments
          ‘-1’, ‘0’, ‘1’, and ‘2’ are permitted.  They are interpreted
          as ‘'stdname'’, ‘'calls'’, ‘'time'’, and ‘'cumulative'’
          respectively.  If this old style format (numeric) is used,
          only one sort key (the numeric key) will be used, and
          additional arguments will be silently ignored.

          Added in version 3.7: Added the SortKey enum.

      -- Method: reverse_order ()

          This method for the ‘Stats’ class reverses the ordering of the
          basic list within the object.  Note that by default ascending
          vs descending order is properly selected based on the sort key
          of choice.

      -- Method: print_stats (*restrictions)

          This method for the ‘Stats’ class prints out a report as
          described in the *note profile.run(): 44cd. definition.

          The order of the printing is based on the last *note
          sort_stats(): 44c8. operation done on the object (subject to
          caveats in *note add(): 44d8. and *note strip_dirs(): 44ca.).

          The arguments provided (if any) can be used to limit the list
          down to the significant entries.  Initially, the list is taken
          to be the complete set of profiled functions.  Each
          restriction is either an integer (to select a count of lines),
          or a decimal fraction between 0.0 and 1.0 inclusive (to select
          a percentage of lines), or a string that will be interpreted
          as a regular expression (to pattern match the standard name
          that is printed).  If several restrictions are provided, then
          they are applied sequentially.  For example:

               print_stats(.1, 'foo:')

          would first limit the printing to first 10% of list, and then
          only print functions that were part of filename ‘.*foo:’.  In
          contrast, the command:

               print_stats('foo:', .1)

          would limit the list to all functions having file names
          ‘.*foo:’, and then proceed to only print the first 10% of
          them.

      -- Method: print_callers (*restrictions)

          This method for the ‘Stats’ class prints a list of all
          functions that called each function in the profiled database.
          The ordering is identical to that provided by *note
          print_stats(): 44cb, and the definition of the restricting
          argument is also identical.  Each caller is reported on its
          own line.  The format differs slightly depending on the
          profiler that produced the stats:

             * With *note profile: af, a number is shown in parentheses
               after each caller to show how many times this specific
               call was made.  For convenience, a second
               non-parenthesized number repeats the cumulative time
               spent in the function at the right.

             * With *note cProfile: 27, each caller is preceded by three
               numbers: the number of times this specific call was made,
               and the total and cumulative times spent in the current
               function while it was invoked by this specific caller.

      -- Method: print_callees (*restrictions)

          This method for the ‘Stats’ class prints a list of all
          function that were called by the indicated function.  Aside
          from this reversal of direction of calls (re: called vs was
          called by), the arguments and ordering are identical to the
          *note print_callers(): 44db. method.

      -- Method: get_stats_profile ()

          This method returns an instance of StatsProfile, which
          contains a mapping of function names to instances of
          FunctionProfile.  Each FunctionProfile instance holds
          information related to the function’s profile such as how long
          the function took to run, how many times it was called, etc…

          Added in version 3.9: Added the following dataclasses:
          StatsProfile, FunctionProfile.  Added the following function:
          get_stats_profile.


File: python.info,  Node: What Is Deterministic Profiling?,  Next: Limitations,  Prev: The Stats Class,  Up: The Python Profilers

5.27.5.5 What Is Deterministic Profiling?
.........................................

'Deterministic profiling' is meant to reflect the fact that all
'function call', 'function return', and 'exception' events are
monitored, and precise timings are made for the intervals between these
events (during which time the user’s code is executing).  In contrast,
'statistical profiling' (which is not done by this module) randomly
samples the effective instruction pointer, and deduces where time is
being spent.  The latter technique traditionally involves less overhead
(as the code does not need to be instrumented), but provides only
relative indications of where time is being spent.

In Python, since there is an interpreter active during execution, the
presence of instrumented code is not required in order to do
deterministic profiling.  Python automatically provides a 'hook'
(optional callback) for each event.  In addition, the interpreted nature
of Python tends to add so much overhead to execution, that deterministic
profiling tends to only add small processing overhead in typical
applications.  The result is that deterministic profiling is not that
expensive, yet provides extensive run time statistics about the
execution of a Python program.

Call count statistics can be used to identify bugs in code (surprising
counts), and to identify possible inline-expansion points (high call
counts).  Internal time statistics can be used to identify “hot loops”
that should be carefully optimized.  Cumulative time statistics should
be used to identify high level errors in the selection of algorithms.
Note that the unusual handling of cumulative times in this profiler
allows statistics for recursive implementations of algorithms to be
directly compared to iterative implementations.


File: python.info,  Node: Limitations,  Next: Calibration,  Prev: What Is Deterministic Profiling?,  Up: The Python Profilers

5.27.5.6 Limitations
....................

One limitation has to do with accuracy of timing information.  There is
a fundamental problem with deterministic profilers involving accuracy.
The most obvious restriction is that the underlying “clock” is only
ticking at a rate (typically) of about .001 seconds.  Hence no
measurements will be more accurate than the underlying clock.  If enough
measurements are taken, then the “error” will tend to average out.
Unfortunately, removing this first error induces a second source of
error.

The second problem is that it “takes a while” from when an event is
dispatched until the profiler’s call to get the time actually 'gets' the
state of the clock.  Similarly, there is a certain lag when exiting the
profiler event handler from the time that the clock’s value was obtained
(and then squirreled away), until the user’s code is once again
executing.  As a result, functions that are called many times, or call
many functions, will typically accumulate this error.  The error that
accumulates in this fashion is typically less than the accuracy of the
clock (less than one clock tick), but it 'can' accumulate and become
very significant.

The problem is more important with *note profile: af. than with the
lower-overhead *note cProfile: 27.  For this reason, ‘profile’ provides
a means of calibrating itself for a given platform so that this error
can be probabilistically (on the average) removed.  After the profiler
is calibrated, it will be more accurate (in a least square sense), but
it will sometimes produce negative numbers (when call counts are
exceptionally low, and the gods of probability work against you :-).  )
Do 'not' be alarmed by negative numbers in the profile.  They should
'only' appear if you have calibrated your profiler, and the results are
actually better than without calibration.


File: python.info,  Node: Calibration,  Next: Using a custom timer,  Prev: Limitations,  Up: The Python Profilers

5.27.5.7 Calibration
....................

The profiler of the *note profile: af. module subtracts a constant from
each event handling time to compensate for the overhead of calling the
time function, and socking away the results.  By default, the constant
is 0.  The following procedure can be used to obtain a better constant
for a given platform (see *note Limitations: 44e1.).

     import profile
     pr = profile.Profile()
     for i in range(5):
         print(pr.calibrate(10000))

The method executes the number of Python calls given by the argument,
directly and again under the profiler, measuring the time for both.  It
then computes the hidden overhead per profiler event, and returns that
as a float.  For example, on a 1.8Ghz Intel Core i5 running macOS, and
using Python’s time.process_time() as the timer, the magical number is
about 4.04e-6.

The object of this exercise is to get a fairly consistent result.  If
your computer is 'very' fast, or your timer function has poor
resolution, you might have to pass 100000, or even 1000000, to get
consistent results.

When you have a consistent answer, there are three ways you can use it:

     import profile

     # 1. Apply computed bias to all Profile instances created hereafter.
     profile.Profile.bias = your_computed_bias

     # 2. Apply computed bias to a specific Profile instance.
     pr = profile.Profile()
     pr.bias = your_computed_bias

     # 3. Specify computed bias in instance constructor.
     pr = profile.Profile(bias=your_computed_bias)

If you have a choice, you are better off choosing a smaller constant,
and then your results will “less often” show up as negative in profile
statistics.


File: python.info,  Node: Using a custom timer,  Prev: Calibration,  Up: The Python Profilers

5.27.5.8 Using a custom timer
.............................

If you want to change how current time is determined (for example, to
force use of wall-clock time or elapsed process time), pass the timing
function you want to the ‘Profile’ class constructor:

     pr = profile.Profile(your_time_func)

The resulting profiler will then call ‘your_time_func’.  Depending on
whether you are using *note profile.Profile: 9ee. or ‘cProfile.Profile’,
‘your_time_func’’s return value will be interpreted differently:

*note profile.Profile: 9ee.

     ‘your_time_func’ should return a single number, or a list of
     numbers whose sum is the current time (like what *note os.times():
     1159. returns).  If the function returns a single time number, or
     the list of returned numbers has length 2, then you will get an
     especially fast version of the dispatch routine.

     Be warned that you should calibrate the profiler class for the
     timer function that you choose (see *note Calibration: 44e3.).  For
     most machines, a timer that returns a lone integer value will
     provide the best results in terms of low overhead during profiling.
     (*note os.times(): 1159. is 'pretty' bad, as it returns a tuple of
     floating-point values).  If you want to substitute a better timer
     in the cleanest fashion, derive a class and hardwire a replacement
     dispatch method that best handles your timer call, along with the
     appropriate calibration constant.

‘cProfile.Profile’

     ‘your_time_func’ should return a single number.  If it returns
     integers, you can also invoke the class constructor with a second
     argument specifying the real duration of one unit of time.  For
     example, if ‘your_integer_time_func’ returns times measured in
     thousands of seconds, you would construct the ‘Profile’ instance as
     follows:

          pr = cProfile.Profile(your_integer_time_func, 0.001)

     As the ‘cProfile.Profile’ class cannot be calibrated, custom timer
     functions should be used with care and should be as fast as
     possible.  For the best results with a custom timer, it might be
     necessary to hard-code it in the C source of the internal ‘_lsprof’
     module.

Python 3.3 adds several new functions in *note time: ee. that can be
used to make precise measurements of process or wall-clock time.  For
example, see *note time.perf_counter(): a97.


File: python.info,  Node: timeit — Measure execution time of small code snippets,  Next: trace — Trace or track Python statement execution,  Prev: The Python Profilers,  Up: Debugging and Profiling

5.27.6 ‘timeit’ — Measure execution time of small code snippets
---------------------------------------------------------------

'Source code:' Lib/timeit.py(1)

__________________________________________________________________

This module provides a simple way to time small bits of Python code.  It
has both a *note Command-Line Interface: 44e9. as well as a *note
callable: 44ea. one.  It avoids a number of common traps for measuring
execution times.  See also Tim Peters’ introduction to the “Algorithms”
chapter in the second edition of 'Python Cookbook', published by
O’Reilly.

* Menu:

* Basic Examples: Basic Examples<2>.
* Python Interface::
* Command-Line Interface: Command-Line Interface<3>.
* Examples: Examples<30>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/timeit.py


File: python.info,  Node: Basic Examples<2>,  Next: Python Interface,  Up: timeit — Measure execution time of small code snippets

5.27.6.1 Basic Examples
.......................

The following example shows how the *note Command-Line Interface: 44e9.
can be used to compare three different expressions:

     $ python -m timeit "'-'.join(str(n) for n in range(100))"
     10000 loops, best of 5: 30.2 usec per loop
     $ python -m timeit "'-'.join([str(n) for n in range(100)])"
     10000 loops, best of 5: 27.5 usec per loop
     $ python -m timeit "'-'.join(map(str, range(100)))"
     10000 loops, best of 5: 23.2 usec per loop

This can be achieved from the *note Python Interface: 44ea. with:

     >>> import timeit
     >>> timeit.timeit('"-".join(str(n) for n in range(100))', number=10000)
     0.3018611848820001
     >>> timeit.timeit('"-".join([str(n) for n in range(100)])', number=10000)
     0.2727368790656328
     >>> timeit.timeit('"-".join(map(str, range(100)))', number=10000)
     0.23702679807320237

A callable can also be passed from the *note Python Interface: 44ea.:

     >>> timeit.timeit(lambda: "-".join(map(str, range(100))), number=10000)
     0.19665591977536678

Note however that *note timeit(): eb2. will automatically determine the
number of repetitions only when the command-line interface is used.  In
the *note Examples: 44ec. section you can find more advanced examples.


File: python.info,  Node: Python Interface,  Next: Command-Line Interface<3>,  Prev: Basic Examples<2>,  Up: timeit — Measure execution time of small code snippets

5.27.6.2 Python Interface
.........................

The module defines three convenience functions and a public class:

 -- Function: timeit.timeit (stmt='pass', setup='pass', timer=<default
          timer>, number=1000000, globals=None)

     Create a *note Timer: 1517. instance with the given statement,
     'setup' code and 'timer' function and run its *note timeit(): d14.
     method with 'number' executions.  The optional 'globals' argument
     specifies a namespace in which to execute the code.

     Changed in version 3.5: The optional 'globals' parameter was added.

 -- Function: timeit.repeat (stmt='pass', setup='pass', timer=<default
          timer>, repeat=5, number=1000000, globals=None)

     Create a *note Timer: 1517. instance with the given statement,
     'setup' code and 'timer' function and run its *note repeat(): 44ef.
     method with the given 'repeat' count and 'number' executions.  The
     optional 'globals' argument specifies a namespace in which to
     execute the code.

     Changed in version 3.5: The optional 'globals' parameter was added.

     Changed in version 3.7: Default value of 'repeat' changed from 3 to
     5.

 -- Function: timeit.default_timer ()

     The default timer, which is always time.perf_counter(), returns
     float seconds.  An alternative, time.perf_counter_ns, returns
     integer nanoseconds.

     Changed in version 3.3: *note time.perf_counter(): a97. is now the
     default timer.

 -- Class: timeit.Timer (stmt='pass', setup='pass', timer=<timer
          function>, globals=None)

     Class for timing execution speed of small code snippets.

     The constructor takes a statement to be timed, an additional
     statement used for setup, and a timer function.  Both statements
     default to ‘'pass'’; the timer function is platform-dependent (see
     the module doc string).  'stmt' and 'setup' may also contain
     multiple statements separated by ‘;’ or newlines, as long as they
     don’t contain multi-line string literals.  The statement will by
     default be executed within timeit’s namespace; this behavior can be
     controlled by passing a namespace to 'globals'.

     To measure the execution time of the first statement, use the *note
     timeit(): d14. method.  The *note repeat(): 44ef. and *note
     autorange(): d13. methods are convenience methods to call
     ‘timeit()’ multiple times.

     The execution time of 'setup' is excluded from the overall timed
     execution run.

     The 'stmt' and 'setup' parameters can also take objects that are
     callable without arguments.  This will embed calls to them in a
     timer function that will then be executed by *note timeit(): d14.
     Note that the timing overhead is a little larger in this case
     because of the extra function calls.

     Changed in version 3.5: The optional 'globals' parameter was added.

      -- Method: timeit (number=1000000)

          Time 'number' executions of the main statement.  This executes
          the setup statement once, and then returns the time it takes
          to execute the main statement a number of times.  The default
          timer returns seconds as a float.  The argument is the number
          of times through the loop, defaulting to one million.  The
          main statement, the setup statement and the timer function to
          be used are passed to the constructor.

               Note: By default, ‘timeit()’ temporarily turns off *note
               garbage collection: 1a83. during the timing.  The
               advantage of this approach is that it makes independent
               timings more comparable.  The disadvantage is that GC may
               be an important component of the performance of the
               function being measured.  If so, GC can be re-enabled as
               the first statement in the 'setup' string.  For example:

                    timeit.Timer('for i in range(10): oct(i)', 'gc.enable()').timeit()

      -- Method: autorange (callback=None)

          Automatically determine how many times to call *note timeit():
          d14.

          This is a convenience function that calls *note timeit(): d14.
          repeatedly so that the total time >= 0.2 second, returning the
          eventual (number of loops, time taken for that number of
          loops).  It calls ‘timeit()’ with increasing numbers from the
          sequence 1, 2, 5, 10, 20, 50, … until the time taken is at
          least 0.2 seconds.

          If 'callback' is given and is not ‘None’, it will be called
          after each trial with two arguments: ‘callback(number,
          time_taken)’.

          Added in version 3.6.

      -- Method: repeat (repeat=5, number=1000000)

          Call *note timeit(): d14. a few times.

          This is a convenience function that calls the *note timeit():
          d14. repeatedly, returning a list of results.  The first
          argument specifies how many times to call ‘timeit()’.  The
          second argument specifies the 'number' argument for
          ‘timeit()’.

               Note: It’s tempting to calculate mean and standard
               deviation from the result vector and report these.
               However, this is not very useful.  In a typical case, the
               lowest value gives a lower bound for how fast your
               machine can run the given code snippet; higher values in
               the result vector are typically not caused by variability
               in Python’s speed, but by other processes interfering
               with your timing accuracy.  So the *note min(): f3f. of
               the result is probably the only number you should be
               interested in.  After that, you should look at the entire
               vector and apply common sense rather than statistics.

          Changed in version 3.7: Default value of 'repeat' changed from
          3 to 5.

      -- Method: print_exc (file=None)

          Helper to print a traceback from the timed code.

          Typical use:

               t = Timer(...)       # outside the try/except
               try:
                   t.timeit(...)    # or t.repeat(...)
               except Exception:
                   t.print_exc()

          The advantage over the standard traceback is that source lines
          in the compiled template will be displayed.  The optional
          'file' argument directs where the traceback is sent; it
          defaults to *note sys.stderr: 943.


File: python.info,  Node: Command-Line Interface<3>,  Next: Examples<30>,  Prev: Python Interface,  Up: timeit — Measure execution time of small code snippets

5.27.6.3 Command-Line Interface
...............................

When called as a program from the command line, the following form is
used:

     python -m timeit [-n N] [-r N] [-u U] [-s S] [-p] [-v] [-h] [statement ...]

Where the following options are understood:

 -- Option: -n N, --number=N

     how many times to execute ‘statement’

 -- Option: -r N, --repeat=N

     how many times to repeat the timer (default 5)

 -- Option: -s S, --setup=S

     statement to be executed once initially (default ‘pass’)

 -- Option: -p, --process

     measure process time, not wallclock time, using *note
     time.process_time(): a98. instead of *note time.perf_counter():
     a97, which is the default

     Added in version 3.3.

 -- Option: -u, --unit=U

     specify a time unit for timer output; can select ‘nsec’, ‘usec’,
     ‘msec’, or ‘sec’

     Added in version 3.5.

 -- Option: -v, --verbose

     print raw timing results; repeat for more digits precision

 -- Option: -h, --help

     print a short usage message and exit

A multi-line statement may be given by specifying each line as a
separate statement argument; indented lines are possible by enclosing an
argument in quotes and using leading spaces.  Multiple *note -s: 44f7.
options are treated similarly.

If *note -n: 44f3. is not given, a suitable number of loops is
calculated by trying increasing numbers from the sequence 1, 2, 5, 10,
20, 50, … until the total time is at least 0.2 seconds.

*note default_timer(): 44f0. measurements can be affected by other
programs running on the same machine, so the best thing to do when
accurate timing is necessary is to repeat the timing a few times and use
the best time.  The *note -r: 44f5. option is good for this; the default
of 5 repetitions is probably enough in most cases.  You can use *note
time.process_time(): a98. to measure CPU time.

     Note: There is a certain baseline overhead associated with
     executing a pass statement.  The code here doesn’t try to hide it,
     but you should be aware of it.  The baseline overhead can be
     measured by invoking the program without arguments, and it might
     differ between Python versions.


File: python.info,  Node: Examples<30>,  Prev: Command-Line Interface<3>,  Up: timeit — Measure execution time of small code snippets

5.27.6.4 Examples
.................

It is possible to provide a setup statement that is executed only once
at the beginning:

     $ python -m timeit -s "text = 'sample string'; char = 'g'" "char in text"
     5000000 loops, best of 5: 0.0877 usec per loop
     $ python -m timeit -s "text = 'sample string'; char = 'g'" "text.find(char)"
     1000000 loops, best of 5: 0.342 usec per loop

In the output, there are three fields.  The loop count, which tells you
how many times the statement body was run per timing loop repetition.
The repetition count (‘best of 5’) which tells you how many times the
timing loop was repeated, and finally the time the statement body took
on average within the best repetition of the timing loop.  That is, the
time the fastest repetition took divided by the loop count.

     >>> import timeit
     >>> timeit.timeit('char in text', setup='text = "sample string"; char = "g"')
     0.41440500499993504
     >>> timeit.timeit('text.find(char)', setup='text = "sample string"; char = "g"')
     1.7246671520006203

The same can be done using the *note Timer: 1517. class and its methods:

     >>> import timeit
     >>> t = timeit.Timer('char in text', setup='text = "sample string"; char = "g"')
     >>> t.timeit()
     0.3955516149999312
     >>> t.repeat()
     [0.40183617287970225, 0.37027556854118704, 0.38344867356679524, 0.3712595970846668, 0.37866875250654886]

The following examples show how to time expressions that contain
multiple lines.  Here we compare the cost of using *note hasattr(): 4d5.
vs.  *note try: 6ec./*note except: 18b. to test for missing and present
object attributes:

     $ python -m timeit "try:" "  str.__bool__" "except AttributeError:" "  pass"
     20000 loops, best of 5: 15.7 usec per loop
     $ python -m timeit "if hasattr(str, '__bool__'): pass"
     50000 loops, best of 5: 4.26 usec per loop

     $ python -m timeit "try:" "  int.__bool__" "except AttributeError:" "  pass"
     200000 loops, best of 5: 1.43 usec per loop
     $ python -m timeit "if hasattr(int, '__bool__'): pass"
     100000 loops, best of 5: 2.23 usec per loop

     >>> import timeit
     >>> # attribute is missing
     >>> s = """\
     ... try:
     ...     str.__bool__
     ... except AttributeError:
     ...     pass
     ... """
     >>> timeit.timeit(stmt=s, number=100000)
     0.9138244460009446
     >>> s = "if hasattr(str, '__bool__'): pass"
     >>> timeit.timeit(stmt=s, number=100000)
     0.5829014980008651
     >>>
     >>> # attribute is present
     >>> s = """\
     ... try:
     ...     int.__bool__
     ... except AttributeError:
     ...     pass
     ... """
     >>> timeit.timeit(stmt=s, number=100000)
     0.04215312199994514
     >>> s = "if hasattr(int, '__bool__'): pass"
     >>> timeit.timeit(stmt=s, number=100000)
     0.08588060699912603

To give the ‘timeit’ module access to functions you define, you can pass
a 'setup' parameter which contains an import statement:

     def test():
         """Stupid test function"""
         L = [i for i in range(100)]

     if __name__ == '__main__':
         import timeit
         print(timeit.timeit("test()", setup="from __main__ import test"))

Another option is to pass *note globals(): 19ae. to the 'globals'
parameter, which will cause the code to be executed within your current
global namespace.  This can be more convenient than individually
specifying imports:

     def f(x):
         return x**2
     def g(x):
         return x**4
     def h(x):
         return x**8

     import timeit
     print(timeit.timeit('[func(42) for func in (f,g,h)]', globals=globals()))


File: python.info,  Node: trace — Trace or track Python statement execution,  Next: tracemalloc — Trace memory allocations,  Prev: timeit — Measure execution time of small code snippets,  Up: Debugging and Profiling

5.27.7 ‘trace’ — Trace or track Python statement execution
----------------------------------------------------------

'Source code:' Lib/trace.py(1)

__________________________________________________________________

The ‘trace’ module allows you to trace program execution, generate
annotated statement coverage listings, print caller/callee relationships
and list functions executed during a program run.  It can be used in
another program or from the command line.

See also
........

Coverage.py(2)

     A popular third-party coverage tool that provides HTML output along
     with advanced features such as branch coverage.

* Menu:

* Command-Line Usage: Command-Line Usage<3>.
* Programmatic Interface::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/trace.py

   (2) https://coverage.readthedocs.io/


File: python.info,  Node: Command-Line Usage<3>,  Next: Programmatic Interface,  Up: trace — Trace or track Python statement execution

5.27.7.1 Command-Line Usage
...........................

The ‘trace’ module can be invoked from the command line.  It can be as
simple as

     python -m trace --count -C . somefile.py ...

The above will execute ‘somefile.py’ and generate annotated listings of
all Python modules imported during the execution into the current
directory.

 -- Option: --help

     Display usage and exit.

 -- Option: --version

     Display the version of the module and exit.

Added in version 3.8: Added ‘--module’ option that allows running an
executable module.

* Menu:

* Main options::
* Modifiers::
* Filters::


File: python.info,  Node: Main options,  Next: Modifiers,  Up: Command-Line Usage<3>

5.27.7.2 Main options
.....................

At least one of the following options must be specified when invoking
‘trace’.  The *note -listfuncs: 450a. option is mutually exclusive with
the *note -trace: 450b. and *note -count: 450c. options.  When
‘--listfuncs’ is provided, neither ‘--count’ nor ‘--trace’ are accepted,
and vice versa.

 -- Option: -c, --count

     Produce a set of annotated listing files upon program completion
     that shows how many times each statement was executed.  See also
     *note -coverdir: 450e, *note -file: 450f. and *note -no-report:
     4510. below.

 -- Option: -t, --trace

     Display lines as they are executed.

 -- Option: -l, --listfuncs

     Display the functions executed by running the program.

 -- Option: -r, --report

     Produce an annotated list from an earlier program run that used the
     *note -count: 450c. and *note -file: 450f. option.  This does not
     execute any code.

 -- Option: -T, --trackcalls

     Display the calling relationships exposed by running the program.


File: python.info,  Node: Modifiers,  Next: Filters,  Prev: Main options,  Up: Command-Line Usage<3>

5.27.7.3 Modifiers
..................

 -- Option: -f, --file=<file>

     Name of a file to accumulate counts over several tracing runs.
     Should be used with the *note -count: 450c. option.

 -- Option: -C, --coverdir=<dir>

     Directory where the report files go.  The coverage report for
     ‘package.module’ is written to file
     ‘`dir'/`package'/`module'.cover’.

 -- Option: -m, --missing

     When generating annotated listings, mark lines which were not
     executed with ‘>>>>>>’.

 -- Option: -s, --summary

     When using *note -count: 450c. or *note -report: 4513, write a
     brief summary to stdout for each file processed.

 -- Option: -R, --no-report

     Do not generate annotated listings.  This is useful if you intend
     to make several runs with *note -count: 450c, and then produce a
     single set of annotated listings at the end.

 -- Option: -g, --timing

     Prefix each line with the time since the program started.  Only
     used while tracing.


File: python.info,  Node: Filters,  Prev: Modifiers,  Up: Command-Line Usage<3>

5.27.7.4 Filters
................

These options may be repeated multiple times.

 -- Option: --ignore-module=<mod>

     Ignore each of the given module names and its submodules (if it is
     a package).  The argument can be a list of names separated by a
     comma.

 -- Option: --ignore-dir=<dir>

     Ignore all modules and packages in the named directory and
     subdirectories.  The argument can be a list of directories
     separated by *note os.pathsep: 1eec.


File: python.info,  Node: Programmatic Interface,  Prev: Command-Line Usage<3>,  Up: trace — Trace or track Python statement execution

5.27.7.5 Programmatic Interface
...............................

 -- Class: trace.Trace (count=1, trace=1, countfuncs=0, countcallers=0,
          ignoremods=(), ignoredirs=(), infile=None, outfile=None,
          timing=False)

     Create an object to trace execution of a single statement or
     expression.  All parameters are optional.  'count' enables counting
     of line numbers.  'trace' enables line execution tracing.
     'countfuncs' enables listing of the functions called during the
     run.  'countcallers' enables call relationship tracking.
     'ignoremods' is a list of modules or packages to ignore.
     'ignoredirs' is a list of directories whose modules or packages
     should be ignored.  'infile' is the name of the file from which to
     read stored count information.  'outfile' is the name of the file
     in which to write updated count information.  'timing' enables a
     timestamp relative to when tracing was started to be displayed.

      -- Method: run (cmd)

          Execute the command and gather statistics from the execution
          with the current tracing parameters.  'cmd' must be a string
          or code object, suitable for passing into *note exec(): 17f.

      -- Method: runctx (cmd, globals=None, locals=None)

          Execute the command and gather statistics from the execution
          with the current tracing parameters, in the defined global and
          local environments.  If not defined, 'globals' and 'locals'
          default to empty dictionaries.

      -- Method: runfunc (func, /, *args, **kwds)

          Call 'func' with the given arguments under control of the
          ‘Trace’ object with the current tracing parameters.

      -- Method: results ()

          Return a *note CoverageResults: 452a. object that contains the
          cumulative results of all previous calls to ‘run’, ‘runctx’
          and ‘runfunc’ for the given ‘Trace’ instance.  Does not reset
          the accumulated trace results.

 -- Class: trace.CoverageResults

     A container for coverage results, created by *note Trace.results():
     4529.  Should not be created directly by the user.

      -- Method: update (other)

          Merge in data from another ‘CoverageResults’ object.

      -- Method: write_results (show_missing=True, summary=False,
               coverdir=None, *, ignore_missing_files=False)

          Write coverage results.  Set 'show_missing' to show lines that
          had no hits.  Set 'summary' to include in the output the
          coverage summary per module.  'coverdir' specifies the
          directory into which the coverage result files will be output.
          If ‘None’, the results for each source file are placed in its
          directory.

          If 'ignore_missing_files' is ‘True’, coverage counts for files
          that no longer exist are silently ignored.  Otherwise, a
          missing file will raise a *note FileNotFoundError: 42e.

          Changed in version 3.13: Added 'ignore_missing_files'
          parameter.

A simple example demonstrating the use of the programmatic interface:

     import sys
     import trace

     # create a Trace object, telling it what to ignore, and whether to
     # do tracing or line-counting or both.
     tracer = trace.Trace(
         ignoredirs=[sys.prefix, sys.exec_prefix],
         trace=0,
         count=1)

     # run the new command using the given tracer
     tracer.run('main()')

     # make a report, placing output in the current directory
     r = tracer.results()
     r.write_results(show_missing=True, coverdir=".")


File: python.info,  Node: tracemalloc — Trace memory allocations,  Prev: trace — Trace or track Python statement execution,  Up: Debugging and Profiling

5.27.8 ‘tracemalloc’ — Trace memory allocations
-----------------------------------------------

Added in version 3.4.

'Source code:' Lib/tracemalloc.py(1)

__________________________________________________________________

The tracemalloc module is a debug tool to trace memory blocks allocated
by Python.  It provides the following information:

   * Traceback where an object was allocated

   * Statistics on allocated memory blocks per filename and per line
     number: total size, number and average size of allocated memory
     blocks

   * Compute the differences between two snapshots to detect memory
     leaks

To trace most memory blocks allocated by Python, the module should be
started as early as possible by setting the *note PYTHONTRACEMALLOC:
1ee4. environment variable to ‘1’, or by using *note -X: 176.
‘tracemalloc’ command line option.  The *note tracemalloc.start(): 1ee3.
function can be called at runtime to start tracing Python memory
allocations.

By default, a trace of an allocated memory block only stores the most
recent frame (1 frame).  To store 25 frames at startup: set the *note
PYTHONTRACEMALLOC: 1ee4. environment variable to ‘25’, or use the *note
-X: 176. ‘tracemalloc=25’ command line option.

* Menu:

* Examples: Examples<31>.
* API::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tracemalloc.py


File: python.info,  Node: Examples<31>,  Next: API,  Up: tracemalloc — Trace memory allocations

5.27.8.1 Examples
.................

* Menu:

* Display the top 10::
* Compute differences::
* Get the traceback of a memory block::
* Pretty top::


File: python.info,  Node: Display the top 10,  Next: Compute differences,  Up: Examples<31>

5.27.8.2 Display the top 10
...........................

Display the 10 files allocating the most memory:

     import tracemalloc

     tracemalloc.start()

     # ... run your application ...

     snapshot = tracemalloc.take_snapshot()
     top_stats = snapshot.statistics('lineno')

     print("[ Top 10 ]")
     for stat in top_stats[:10]:
         print(stat)

Example of output of the Python test suite:

     [ Top 10 ]
     <frozen importlib._bootstrap>:716: size=4855 KiB, count=39328, average=126 B
     <frozen importlib._bootstrap>:284: size=521 KiB, count=3199, average=167 B
     /usr/lib/python3.4/collections/__init__.py:368: size=244 KiB, count=2315, average=108 B
     /usr/lib/python3.4/unittest/case.py:381: size=185 KiB, count=779, average=243 B
     /usr/lib/python3.4/unittest/case.py:402: size=154 KiB, count=378, average=416 B
     /usr/lib/python3.4/abc.py:133: size=88.7 KiB, count=347, average=262 B
     <frozen importlib._bootstrap>:1446: size=70.4 KiB, count=911, average=79 B
     <frozen importlib._bootstrap>:1454: size=52.0 KiB, count=25, average=2131 B
     <string>:5: size=49.7 KiB, count=148, average=344 B
     /usr/lib/python3.4/sysconfig.py:411: size=48.0 KiB, count=1, average=48.0 KiB

We can see that Python loaded ‘4855 KiB’ data (bytecode and constants)
from modules and that the *note collections: 1d. module allocated ‘244
KiB’ to build *note namedtuple: 1ca. types.

See *note Snapshot.statistics(): 4532. for more options.


File: python.info,  Node: Compute differences,  Next: Get the traceback of a memory block,  Prev: Display the top 10,  Up: Examples<31>

5.27.8.3 Compute differences
............................

Take two snapshots and display the differences:

     import tracemalloc
     tracemalloc.start()
     # ... start your application ...

     snapshot1 = tracemalloc.take_snapshot()
     # ... call the function leaking memory ...
     snapshot2 = tracemalloc.take_snapshot()

     top_stats = snapshot2.compare_to(snapshot1, 'lineno')

     print("[ Top 10 differences ]")
     for stat in top_stats[:10]:
         print(stat)

Example of output before/after running some tests of the Python test
suite:

     [ Top 10 differences ]
     <frozen importlib._bootstrap>:716: size=8173 KiB (+4428 KiB), count=71332 (+39369), average=117 B
     /usr/lib/python3.4/linecache.py:127: size=940 KiB (+940 KiB), count=8106 (+8106), average=119 B
     /usr/lib/python3.4/unittest/case.py:571: size=298 KiB (+298 KiB), count=589 (+589), average=519 B
     <frozen importlib._bootstrap>:284: size=1005 KiB (+166 KiB), count=7423 (+1526), average=139 B
     /usr/lib/python3.4/mimetypes.py:217: size=112 KiB (+112 KiB), count=1334 (+1334), average=86 B
     /usr/lib/python3.4/http/server.py:848: size=96.0 KiB (+96.0 KiB), count=1 (+1), average=96.0 KiB
     /usr/lib/python3.4/inspect.py:1465: size=83.5 KiB (+83.5 KiB), count=109 (+109), average=784 B
     /usr/lib/python3.4/unittest/mock.py:491: size=77.7 KiB (+77.7 KiB), count=143 (+143), average=557 B
     /usr/lib/python3.4/urllib/parse.py:476: size=71.8 KiB (+71.8 KiB), count=969 (+969), average=76 B
     /usr/lib/python3.4/contextlib.py:38: size=67.2 KiB (+67.2 KiB), count=126 (+126), average=546 B

We can see that Python has loaded ‘8173 KiB’ of module data (bytecode
and constants), and that this is ‘4428 KiB’ more than had been loaded
before the tests, when the previous snapshot was taken.  Similarly, the
*note linecache: 85. module has cached ‘940 KiB’ of Python source code
to format tracebacks, all of it since the previous snapshot.

If the system has little free memory, snapshots can be written on disk
using the *note Snapshot.dump(): 4534. method to analyze the snapshot
offline.  Then use the *note Snapshot.load(): 4535. method reload the
snapshot.


File: python.info,  Node: Get the traceback of a memory block,  Next: Pretty top,  Prev: Compute differences,  Up: Examples<31>

5.27.8.4 Get the traceback of a memory block
............................................

Code to display the traceback of the biggest memory block:

     import tracemalloc

     # Store 25 frames
     tracemalloc.start(25)

     # ... run your application ...

     snapshot = tracemalloc.take_snapshot()
     top_stats = snapshot.statistics('traceback')

     # pick the biggest memory block
     stat = top_stats[0]
     print("%s memory blocks: %.1f KiB" % (stat.count, stat.size / 1024))
     for line in stat.traceback.format():
         print(line)

Example of output of the Python test suite (traceback limited to 25
frames):

     903 memory blocks: 870.1 KiB
       File "<frozen importlib._bootstrap>", line 716
       File "<frozen importlib._bootstrap>", line 1036
       File "<frozen importlib._bootstrap>", line 934
       File "<frozen importlib._bootstrap>", line 1068
       File "<frozen importlib._bootstrap>", line 619
       File "<frozen importlib._bootstrap>", line 1581
       File "<frozen importlib._bootstrap>", line 1614
       File "/usr/lib/python3.4/doctest.py", line 101
         import pdb
       File "<frozen importlib._bootstrap>", line 284
       File "<frozen importlib._bootstrap>", line 938
       File "<frozen importlib._bootstrap>", line 1068
       File "<frozen importlib._bootstrap>", line 619
       File "<frozen importlib._bootstrap>", line 1581
       File "<frozen importlib._bootstrap>", line 1614
       File "/usr/lib/python3.4/test/support/__init__.py", line 1728
         import doctest
       File "/usr/lib/python3.4/test/test_pickletools.py", line 21
         support.run_doctest(pickletools)
       File "/usr/lib/python3.4/test/regrtest.py", line 1276
         test_runner()
       File "/usr/lib/python3.4/test/regrtest.py", line 976
         display_failure=not verbose)
       File "/usr/lib/python3.4/test/regrtest.py", line 761
         match_tests=ns.match_tests)
       File "/usr/lib/python3.4/test/regrtest.py", line 1563
         main()
       File "/usr/lib/python3.4/test/__main__.py", line 3
         regrtest.main_in_temp_cwd()
       File "/usr/lib/python3.4/runpy.py", line 73
         exec(code, run_globals)
       File "/usr/lib/python3.4/runpy.py", line 160
         "__main__", fname, loader, pkg_name)

We can see that the most memory was allocated in the *note importlib:
77. module to load data (bytecode and constants) from modules: ‘870.1
KiB’.  The traceback is where the ‘importlib’ loaded data most recently:
on the ‘import pdb’ line of the *note doctest: 3a. module.  The
traceback may change if a new module is loaded.


File: python.info,  Node: Pretty top,  Prev: Get the traceback of a memory block,  Up: Examples<31>

5.27.8.5 Pretty top
...................

Code to display the 10 lines allocating the most memory with a pretty
output, ignoring ‘<frozen importlib._bootstrap>’ and ‘<unknown>’ files:

     import linecache
     import os
     import tracemalloc

     def display_top(snapshot, key_type='lineno', limit=10):
         snapshot = snapshot.filter_traces((
             tracemalloc.Filter(False, "<frozen importlib._bootstrap>"),
             tracemalloc.Filter(False, "<unknown>"),
         ))
         top_stats = snapshot.statistics(key_type)

         print("Top %s lines" % limit)
         for index, stat in enumerate(top_stats[:limit], 1):
             frame = stat.traceback[0]
             print("#%s: %s:%s: %.1f KiB"
                   % (index, frame.filename, frame.lineno, stat.size / 1024))
             line = linecache.getline(frame.filename, frame.lineno).strip()
             if line:
                 print('    %s' % line)

         other = top_stats[limit:]
         if other:
             size = sum(stat.size for stat in other)
             print("%s other: %.1f KiB" % (len(other), size / 1024))
         total = sum(stat.size for stat in top_stats)
         print("Total allocated size: %.1f KiB" % (total / 1024))

     tracemalloc.start()

     # ... run your application ...

     snapshot = tracemalloc.take_snapshot()
     display_top(snapshot)

Example of output of the Python test suite:

     Top 10 lines
     #1: Lib/base64.py:414: 419.8 KiB
         _b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
     #2: Lib/base64.py:306: 419.8 KiB
         _a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
     #3: collections/__init__.py:368: 293.6 KiB
         exec(class_definition, namespace)
     #4: Lib/abc.py:133: 115.2 KiB
         cls = super().__new__(mcls, name, bases, namespace)
     #5: unittest/case.py:574: 103.1 KiB
         testMethod()
     #6: Lib/linecache.py:127: 95.4 KiB
         lines = fp.readlines()
     #7: urllib/parse.py:476: 71.8 KiB
         for a in _hexdig for b in _hexdig}
     #8: <string>:5: 62.0 KiB
     #9: Lib/_weakrefset.py:37: 60.0 KiB
         self.data = set()
     #10: Lib/base64.py:142: 59.8 KiB
         _b32tab2 = [a + b for a in _b32tab for b in _b32tab]
     6220 other: 3602.8 KiB
     Total allocated size: 5303.1 KiB

See *note Snapshot.statistics(): 4532. for more options.

* Menu:

* Record the current and peak size of all traced memory blocks::


File: python.info,  Node: Record the current and peak size of all traced memory blocks,  Up: Pretty top

5.27.8.6 Record the current and peak size of all traced memory blocks
.....................................................................

The following code computes two sums like ‘0 + 1 + 2 + ...’
inefficiently, by creating a list of those numbers.  This list consumes
a lot of memory temporarily.  We can use *note get_traced_memory():
4539. and *note reset_peak(): 945. to observe the small memory usage
after the sum is computed as well as the peak memory usage during the
computations:

     import tracemalloc

     tracemalloc.start()

     # Example code: compute a sum with a large temporary list
     large_sum = sum(list(range(100000)))

     first_size, first_peak = tracemalloc.get_traced_memory()

     tracemalloc.reset_peak()

     # Example code: compute a sum with a small temporary list
     small_sum = sum(list(range(1000)))

     second_size, second_peak = tracemalloc.get_traced_memory()

     print(f"{first_size=}, {first_peak=}")
     print(f"{second_size=}, {second_peak=}")

Output:

     first_size=664, first_peak=3592984
     second_size=804, second_peak=29704

Using *note reset_peak(): 945. ensured we could accurately record the
peak during the computation of ‘small_sum’, even though it is much
smaller than the overall peak size of memory blocks since the *note
start(): 1ee3. call.  Without the call to ‘reset_peak()’, ‘second_peak’
would still be the peak from the computation ‘large_sum’ (that is, equal
to ‘first_peak’).  In this case, both peaks are much higher than the
final memory usage, and which suggests we could optimise (by removing
the unnecessary call to *note list: 614, and writing ‘sum(range(...))’).


File: python.info,  Node: API,  Prev: Examples<31>,  Up: tracemalloc — Trace memory allocations

5.27.8.7 API
............

* Menu:

* Functions: Functions<11>.
* DomainFilter::
* Filter::
* Frame::
* Snapshot::
* Statistic::
* StatisticDiff::
* Trace::
* Traceback::


File: python.info,  Node: Functions<11>,  Next: DomainFilter,  Up: API

5.27.8.8 Functions
..................

 -- Function: tracemalloc.clear_traces ()

     Clear traces of memory blocks allocated by Python.

     See also *note stop(): 1687.

 -- Function: tracemalloc.get_object_traceback (obj)

     Get the traceback where the Python object 'obj' was allocated.
     Return a *note Traceback: bb4. instance, or ‘None’ if the
     ‘tracemalloc’ module is not tracing memory allocations or did not
     trace the allocation of the object.

     See also *note gc.get_referrers(): 80a. and *note sys.getsizeof():
     187e. functions.

 -- Function: tracemalloc.get_traceback_limit ()

     Get the maximum number of frames stored in the traceback of a
     trace.

     The ‘tracemalloc’ module must be tracing memory allocations to get
     the limit, otherwise an exception is raised.

     The limit is set by the *note start(): 1ee3. function.

 -- Function: tracemalloc.get_traced_memory ()

     Get the current size and peak size of memory blocks traced by the
     ‘tracemalloc’ module as a tuple: ‘(current: int, peak: int)’.

 -- Function: tracemalloc.reset_peak ()

     Set the peak size of memory blocks traced by the ‘tracemalloc’
     module to the current size.

     Do nothing if the ‘tracemalloc’ module is not tracing memory
     allocations.

     This function only modifies the recorded peak size, and does not
     modify or clear any traces, unlike *note clear_traces(): 453c.
     Snapshots taken with *note take_snapshot(): 453e. before a call to
     ‘reset_peak()’ can be meaningfully compared to snapshots taken
     after the call.

     See also *note get_traced_memory(): 4539.

     Added in version 3.9.

 -- Function: tracemalloc.get_tracemalloc_memory ()

     Get the memory usage in bytes of the ‘tracemalloc’ module used to
     store traces of memory blocks.  Return an *note int: 257.

 -- Function: tracemalloc.is_tracing ()

     ‘True’ if the ‘tracemalloc’ module is tracing Python memory
     allocations, ‘False’ otherwise.

     See also *note start(): 1ee3. and *note stop(): 1687. functions.

 -- Function: tracemalloc.start (nframe: int = 1)

     Start tracing Python memory allocations: install hooks on Python
     memory allocators.  Collected tracebacks of traces will be limited
     to 'nframe' frames.  By default, a trace of a memory block only
     stores the most recent frame: the limit is ‘1’.  'nframe' must be
     greater or equal to ‘1’.

     You can still read the original number of total frames that
     composed the traceback by looking at the *note
     Traceback.total_nframe: 4541. attribute.

     Storing more than ‘1’ frame is only useful to compute statistics
     grouped by ‘'traceback'’ or to compute cumulative statistics: see
     the *note Snapshot.compare_to(): 4542. and *note
     Snapshot.statistics(): 4532. methods.

     Storing more frames increases the memory and CPU overhead of the
     ‘tracemalloc’ module.  Use the *note get_tracemalloc_memory():
     453f. function to measure how much memory is used by the
     ‘tracemalloc’ module.

     The *note PYTHONTRACEMALLOC: 1ee4. environment variable
     (‘PYTHONTRACEMALLOC=NFRAME’) and the *note -X: 176.
     ‘tracemalloc=NFRAME’ command line option can be used to start
     tracing at startup.

     See also *note stop(): 1687, *note is_tracing(): 4540. and *note
     get_traceback_limit(): 453d. functions.

 -- Function: tracemalloc.stop ()

     Stop tracing Python memory allocations: uninstall hooks on Python
     memory allocators.  Also clears all previously collected traces of
     memory blocks allocated by Python.

     Call *note take_snapshot(): 453e. function to take a snapshot of
     traces before clearing them.

     See also *note start(): 1ee3, *note is_tracing(): 4540. and *note
     clear_traces(): 453c. functions.

 -- Function: tracemalloc.take_snapshot ()

     Take a snapshot of traces of memory blocks allocated by Python.
     Return a new *note Snapshot: 4543. instance.

     The snapshot does not include memory blocks allocated before the
     ‘tracemalloc’ module started to trace memory allocations.

     Tracebacks of traces are limited to *note get_traceback_limit():
     453d. frames.  Use the 'nframe' parameter of the *note start():
     1ee3. function to store more frames.

     The ‘tracemalloc’ module must be tracing memory allocations to take
     a snapshot, see the *note start(): 1ee3. function.

     See also the *note get_object_traceback(): 1cea. function.


File: python.info,  Node: DomainFilter,  Next: Filter,  Prev: Functions<11>,  Up: API

5.27.8.9 DomainFilter
.....................

 -- Class: tracemalloc.DomainFilter (inclusive: bool, domain: int)

     Filter traces of memory blocks by their address space (domain).

     Added in version 3.6.

      -- Attribute: inclusive

          If 'inclusive' is ‘True’ (include), match memory blocks
          allocated in the address space *note domain: 4546.

          If 'inclusive' is ‘False’ (exclude), match memory blocks not
          allocated in the address space *note domain: 4546.

      -- Attribute: domain

          Address space of a memory block (‘int’).  Read-only property.


File: python.info,  Node: Filter,  Next: Frame,  Prev: DomainFilter,  Up: API

5.27.8.10 Filter
................

 -- Class: tracemalloc.Filter (inclusive: bool, filename_pattern: str,
          lineno: int = None, all_frames: bool = False, domain: int =
          None)

     Filter on traces of memory blocks.

     See the *note fnmatch.fnmatch(): 19fa. function for the syntax of
     'filename_pattern'.  The ‘'.pyc'’ file extension is replaced with
     ‘'.py'’.

     Examples:

        * ‘Filter(True, subprocess.__file__)’ only includes traces of
          the *note subprocess: d6. module

        * ‘Filter(False, tracemalloc.__file__)’ excludes traces of the
          ‘tracemalloc’ module

        * ‘Filter(False, "<unknown>")’ excludes empty tracebacks

     Changed in version 3.5: The ‘'.pyo'’ file extension is no longer
     replaced with ‘'.py'’.

     Changed in version 3.6: Added the *note domain: 4549. attribute.

      -- Attribute: domain

          Address space of a memory block (‘int’ or ‘None’).

          tracemalloc uses the domain ‘0’ to trace memory allocations
          made by Python.  C extensions can use other domains to trace
          other resources.

      -- Attribute: inclusive

          If 'inclusive' is ‘True’ (include), only match memory blocks
          allocated in a file with a name matching *note
          filename_pattern: 454b. at line number *note lineno: 454c.

          If 'inclusive' is ‘False’ (exclude), ignore memory blocks
          allocated in a file with a name matching *note
          filename_pattern: 454b. at line number *note lineno: 454c.

      -- Attribute: lineno

          Line number (‘int’) of the filter.  If 'lineno' is ‘None’, the
          filter matches any line number.

      -- Attribute: filename_pattern

          Filename pattern of the filter (‘str’).  Read-only property.

      -- Attribute: all_frames

          If 'all_frames' is ‘True’, all frames of the traceback are
          checked.  If 'all_frames' is ‘False’, only the most recent
          frame is checked.

          This attribute has no effect if the traceback limit is ‘1’.
          See the *note get_traceback_limit(): 453d. function and *note
          Snapshot.traceback_limit: 454e. attribute.


File: python.info,  Node: Frame,  Next: Snapshot,  Prev: Filter,  Up: API

5.27.8.11 Frame
...............

 -- Class: tracemalloc.Frame

     Frame of a traceback.

     The *note Traceback: bb4. class is a sequence of ‘Frame’ instances.

      -- Attribute: filename

          Filename (‘str’).

      -- Attribute: lineno

          Line number (‘int’).


File: python.info,  Node: Snapshot,  Next: Statistic,  Prev: Frame,  Up: API

5.27.8.12 Snapshot
..................

 -- Class: tracemalloc.Snapshot

     Snapshot of traces of memory blocks allocated by Python.

     The *note take_snapshot(): 453e. function creates a snapshot
     instance.

      -- Method: compare_to (old_snapshot: Snapshot, key_type: str,
               cumulative: bool = False)

          Compute the differences with an old snapshot.  Get statistics
          as a sorted list of *note StatisticDiff: 4554. instances
          grouped by 'key_type'.

          See the *note Snapshot.statistics(): 4532. method for
          'key_type' and 'cumulative' parameters.

          The result is sorted from the biggest to the smallest by:
          absolute value of *note StatisticDiff.size_diff: 4555, *note
          StatisticDiff.size: 4556, absolute value of *note
          StatisticDiff.count_diff: 4557, *note Statistic.count: 4558.
          and then by *note StatisticDiff.traceback: 4559.

      -- Method: dump (filename)

          Write the snapshot into a file.

          Use *note load(): 4535. to reload the snapshot.

      -- Method: filter_traces (filters)

          Create a new ‘Snapshot’ instance with a filtered *note traces:
          455b. sequence, 'filters' is a list of *note DomainFilter:
          d18. and *note Filter: 4548. instances.  If 'filters' is an
          empty list, return a new ‘Snapshot’ instance with a copy of
          the traces.

          All inclusive filters are applied at once, a trace is ignored
          if no inclusive filters match it.  A trace is ignored if at
          least one exclusive filter matches it.

          Changed in version 3.6: *note DomainFilter: d18. instances are
          now also accepted in 'filters'.

      -- Method: classmethod load (filename)

          Load a snapshot from a file.

          See also *note dump(): 4534.

      -- Method: statistics (key_type: str, cumulative: bool = False)

          Get statistics as a sorted list of *note Statistic: 455c.
          instances grouped by 'key_type':

          key_type                  description
                                    
          -------------------------------------------------------
                                    
          ‘'filename'’              filename
                                    
                                    
          ‘'lineno'’                filename and line number
                                    
                                    
          ‘'traceback'’             traceback
                                    

          If 'cumulative' is ‘True’, cumulate size and count of memory
          blocks of all frames of the traceback of a trace, not only the
          most recent frame.  The cumulative mode can only be used with
          'key_type' equal to ‘'filename'’ and ‘'lineno'’.

          The result is sorted from the biggest to the smallest by:
          *note Statistic.size: 455d, *note Statistic.count: 4558. and
          then by *note Statistic.traceback: 455e.

      -- Attribute: traceback_limit

          Maximum number of frames stored in the traceback of *note
          traces: 455b.: result of the *note get_traceback_limit():
          453d. when the snapshot was taken.

      -- Attribute: traces

          Traces of all memory blocks allocated by Python: sequence of
          *note Trace: 455f. instances.

          The sequence has an undefined order.  Use the *note
          Snapshot.statistics(): 4532. method to get a sorted list of
          statistics.


File: python.info,  Node: Statistic,  Next: StatisticDiff,  Prev: Snapshot,  Up: API

5.27.8.13 Statistic
...................

 -- Class: tracemalloc.Statistic

     Statistic on memory allocations.

     *note Snapshot.statistics(): 4532. returns a list of ‘Statistic’
     instances.

     See also the *note StatisticDiff: 4554. class.

      -- Attribute: count

          Number of memory blocks (‘int’).

      -- Attribute: size

          Total size of memory blocks in bytes (‘int’).

      -- Attribute: traceback

          Traceback where the memory block was allocated, *note
          Traceback: bb4. instance.


File: python.info,  Node: StatisticDiff,  Next: Trace,  Prev: Statistic,  Up: API

5.27.8.14 StatisticDiff
.......................

 -- Class: tracemalloc.StatisticDiff

     Statistic difference on memory allocations between an old and a new
     *note Snapshot: 4543. instance.

     *note Snapshot.compare_to(): 4542. returns a list of
     ‘StatisticDiff’ instances.  See also the *note Statistic: 455c.
     class.

      -- Attribute: count

          Number of memory blocks in the new snapshot (‘int’): ‘0’ if
          the memory blocks have been released in the new snapshot.

      -- Attribute: count_diff

          Difference of number of memory blocks between the old and the
          new snapshots (‘int’): ‘0’ if the memory blocks have been
          allocated in the new snapshot.

      -- Attribute: size

          Total size of memory blocks in bytes in the new snapshot
          (‘int’): ‘0’ if the memory blocks have been released in the
          new snapshot.

      -- Attribute: size_diff

          Difference of total size of memory blocks in bytes between the
          old and the new snapshots (‘int’): ‘0’ if the memory blocks
          have been allocated in the new snapshot.

      -- Attribute: traceback

          Traceback where the memory blocks were allocated, *note
          Traceback: bb4. instance.


File: python.info,  Node: Trace,  Next: Traceback,  Prev: StatisticDiff,  Up: API

5.27.8.15 Trace
...............

 -- Class: tracemalloc.Trace

     Trace of a memory block.

     The *note Snapshot.traces: 455b. attribute is a sequence of ‘Trace’
     instances.

     Changed in version 3.6: Added the *note domain: 4564. attribute.

      -- Attribute: domain

          Address space of a memory block (‘int’).  Read-only property.

          tracemalloc uses the domain ‘0’ to trace memory allocations
          made by Python.  C extensions can use other domains to trace
          other resources.

      -- Attribute: size

          Size of the memory block in bytes (‘int’).

      -- Attribute: traceback

          Traceback where the memory block was allocated, *note
          Traceback: bb4. instance.


File: python.info,  Node: Traceback,  Prev: Trace,  Up: API

5.27.8.16 Traceback
...................

 -- Class: tracemalloc.Traceback

     Sequence of *note Frame: 4550. instances sorted from the oldest
     frame to the most recent frame.

     A traceback contains at least ‘1’ frame.  If the ‘tracemalloc’
     module failed to get a frame, the filename ‘"<unknown>"’ at line
     number ‘0’ is used.

     When a snapshot is taken, tracebacks of traces are limited to *note
     get_traceback_limit(): 453d. frames.  See the *note
     take_snapshot(): 453e. function.  The original number of frames of
     the traceback is stored in the *note Traceback.total_nframe: 4541.
     attribute.  That allows one to know if a traceback has been
     truncated by the traceback limit.

     The *note Trace.traceback: 4566. attribute is a ‘Traceback’
     instance.

     Changed in version 3.7: Frames are now sorted from the oldest to
     the most recent, instead of most recent to oldest.

      -- Attribute: total_nframe

          Total number of frames that composed the traceback before
          truncation.  This attribute can be set to ‘None’ if the
          information is not available.

     Changed in version 3.9: The *note Traceback.total_nframe: 4541.
     attribute was added.

      -- Method: format (limit=None, most_recent_first=False)

          Format the traceback as a list of lines.  Use the *note
          linecache: 85. module to retrieve lines from the source code.
          If 'limit' is set, format the 'limit' most recent frames if
          'limit' is positive.  Otherwise, format the ‘abs(limit)’
          oldest frames.  If 'most_recent_first' is ‘True’, the order of
          the formatted frames is reversed, returning the most recent
          frame first instead of last.

          Similar to the *note traceback.format_tb(): 4568. function,
          except that ‘format()’ does not include newlines.

          Example:

               print("Traceback (most recent call first):")
               for line in traceback:
                   print(line)

          Output:

               Traceback (most recent call first):
                 File "test.py", line 9
                   obj = Object()
                 File "test.py", line 12
                   tb = tracemalloc.get_object_traceback(f())


File: python.info,  Node: Software Packaging and Distribution,  Next: Python Runtime Services,  Prev: Debugging and Profiling,  Up: The Python Standard Library

5.28 Software Packaging and Distribution
========================================

These libraries help you with publishing and installing Python software.
While these modules are designed to work in conjunction with the Python
Package Index(1), they can also be used with a local index server, or
without any index server at all.

* Menu:

* ensurepip — Bootstrapping the pip installer::
* venv — Creation of virtual environments::
* zipapp — Manage executable Python zip archives::

   ---------- Footnotes ----------

   (1) https://pypi.org


File: python.info,  Node: ensurepip — Bootstrapping the pip installer,  Next: venv — Creation of virtual environments,  Up: Software Packaging and Distribution

5.28.1 ‘ensurepip’ — Bootstrapping the ‘pip’ installer
------------------------------------------------------

Added in version 3.4.

'Source code:' Lib/ensurepip(1)

__________________________________________________________________

The ‘ensurepip’ package provides support for bootstrapping the ‘pip’
installer into an existing Python installation or virtual environment.
This bootstrapping approach reflects the fact that ‘pip’ is an
independent project with its own release cycle, and the latest available
stable version is bundled with maintenance and feature releases of the
CPython reference interpreter.

In most cases, end users of Python shouldn’t need to invoke this module
directly (as ‘pip’ should be bootstrapped by default), but it may be
needed if installing ‘pip’ was skipped when installing Python (or when
creating a virtual environment) or after explicitly uninstalling ‘pip’.

     Note: This module 'does not' access the internet.  All of the
     components needed to bootstrap ‘pip’ are included as internal parts
     of the package.

See also
........

*note Installing Python modules: f2c.

     The end user guide for installing Python packages

PEP 453(2): Explicit bootstrapping of pip in Python installations

     The original rationale and specification for this module.

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

* Menu:

* Command-line interface: Command-line interface<7>.
* Module API::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ensurepip

   (2) https://peps.python.org/pep-0453/


File: python.info,  Node: Command-line interface<7>,  Next: Module API,  Up: ensurepip — Bootstrapping the pip installer

5.28.1.1 Command-line interface
...............................

The command line interface is invoked using the interpreter’s ‘-m’
switch.

The simplest possible invocation is:

     python -m ensurepip

This invocation will install ‘pip’ if it is not already installed, but
otherwise does nothing.  To ensure the installed version of ‘pip’ is at
least as recent as the one available in ‘ensurepip’, pass the
‘--upgrade’ option:

     python -m ensurepip --upgrade

By default, ‘pip’ is installed into the current virtual environment (if
one is active) or into the system site packages (if there is no active
virtual environment).  The installation location can be controlled
through two additional command line options:

 -- Option: --root <dir>

     Installs ‘pip’ relative to the given root directory rather than the
     root of the currently active virtual environment (if any) or the
     default root for the current Python installation.

 -- Option: --user

     Installs ‘pip’ into the user site packages directory rather than
     globally for the current Python installation (this option is not
     permitted inside an active virtual environment).

By default, the scripts ‘pipX’ and ‘pipX.Y’ will be installed (where X.Y
stands for the version of Python used to invoke ‘ensurepip’).  The
scripts installed can be controlled through two additional command line
options:

 -- Option: --altinstall

     If an alternate installation is requested, the ‘pipX’ script will
     'not' be installed.

 -- Option: --default-pip

     If a “default pip” installation is requested, the ‘pip’ script will
     be installed in addition to the two regular scripts.

Providing both of the script selection options will trigger an
exception.


File: python.info,  Node: Module API,  Prev: Command-line interface<7>,  Up: ensurepip — Bootstrapping the pip installer

5.28.1.2 Module API
...................

‘ensurepip’ exposes two functions for programmatic use:

 -- Function: ensurepip.version ()

     Returns a string specifying the available version of pip that will
     be installed when bootstrapping an environment.

 -- Function: ensurepip.bootstrap (root=None, upgrade=False, user=False,
          altinstall=False, default_pip=False, verbosity=0)

     Bootstraps ‘pip’ into the current or designated environment.

     'root' specifies an alternative root directory to install relative
     to.  If 'root' is ‘None’, then installation uses the default
     install location for the current environment.

     'upgrade' indicates whether or not to upgrade an existing
     installation of an earlier version of ‘pip’ to the available
     version.

     'user' indicates whether to use the user scheme rather than
     installing globally.

     By default, the scripts ‘pipX’ and ‘pipX.Y’ will be installed
     (where X.Y stands for the current version of Python).

     If 'altinstall' is set, then ‘pipX’ will 'not' be installed.

     If 'default_pip' is set, then ‘pip’ will be installed in addition
     to the two regular scripts.

     Setting both 'altinstall' and 'default_pip' will trigger *note
     ValueError: 202.

     'verbosity' controls the level of output to *note sys.stdout: aec.
     from the bootstrapping operation.

     Raises an *note auditing event: 1a15. ‘ensurepip.bootstrap’ with
     argument ‘root’.

          Note: The bootstrapping process has side effects on both
          ‘sys.path’ and ‘os.environ’.  Invoking the command line
          interface in a subprocess instead allows these side effects to
          be avoided.

          Note: The bootstrapping process may install additional modules
          required by ‘pip’, but other software should not assume those
          dependencies will always be present by default (as the
          dependencies may be removed in a future version of ‘pip’).


File: python.info,  Node: venv — Creation of virtual environments,  Next: zipapp — Manage executable Python zip archives,  Prev: ensurepip — Bootstrapping the pip installer,  Up: Software Packaging and Distribution

5.28.2 ‘venv’ — Creation of virtual environments
------------------------------------------------

Added in version 3.3.

'Source code:' Lib/venv/(1)

__________________________________________________________________

The ‘venv’ module supports creating lightweight “virtual environments”,
each with their own independent set of Python packages installed in
their *note site: c7. directories.  A virtual environment is created on
top of an existing Python installation, known as the virtual
environment’s “base” Python, and by default is isolated from the
packages in the base environment, so that only those explicitly
installed in the virtual environment are available.

When used from within a virtual environment, common installation tools
such as pip(2) will install Python packages into a virtual environment
without needing to be told to do so explicitly.

A virtual environment is (amongst other things):

   * Used to contain a specific Python interpreter and software
     libraries and binaries which are needed to support a project
     (library or application).  These are by default isolated from
     software in other virtual environments and Python interpreters and
     libraries installed in the operating system.

   * Contained in a directory, conventionally named ‘.venv’ or ‘venv’ in
     the project directory, or under a container directory for lots of
     virtual environments, such as ‘~/.virtualenvs’.

   * Not checked into source control systems such as Git.

   * Considered as disposable – it should be simple to delete and
     recreate it from scratch.  You don’t place any project code in the
     environment.

   * Not considered as movable or copyable – you just recreate the same
     environment in the target location.

See PEP 405(3) for more background on Python virtual environments.

See also
........

Python Packaging User Guide: Creating and using virtual environments(4)

*note Availability: 1ef7.: not Android, not iOS, not WASI.

This module is not supported on *note mobile platforms: 1ffd. or *note
WebAssembly platforms: 1910.

* Menu:

* Creating virtual environments::
* How venvs work::
* API: API<2>.
* An example of extending EnvBuilder::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/venv/

   (2) https://pypi.org/project/pip/

   (3) https://peps.python.org/pep-0405/

   (4) 
https://packaging.python.org/guides/installing-using-pip-and-virtual-environments/#create-and-use-virtual-environments


File: python.info,  Node: Creating virtual environments,  Next: How venvs work,  Up: venv — Creation of virtual environments

5.28.2.1 Creating virtual environments
......................................

*note Virtual environments: 4579. are created by executing the ‘venv’
module:

     python -m venv /path/to/new/virtual/environment

This creates the target directory (including parent directories as
needed) and places a ‘pyvenv.cfg’ file in it with a ‘home’ key pointing
to the Python installation from which the command was run.  It also
creates a ‘bin’ (or ‘Scripts’ on Windows) subdirectory containing a copy
or symlink of the Python executable (as appropriate for the platform or
arguments used at environment creation time).  It also creates a
‘lib/pythonX.Y/site-packages’ subdirectory (on Windows, this is
‘Lib\site-packages’).  If an existing directory is specified, it will be
re-used.

Changed in version 3.5: The use of ‘venv’ is now recommended for
creating virtual environments.

Deprecated since version 3.6, removed in version 3.8: ‘pyvenv’ was the
recommended tool for creating virtual environments for Python 3.3 and
3.4, and replaced in 3.5 by executing ‘venv’ directly.

On Windows, invoke the ‘venv’ command as follows:

     PS> python -m venv C:\path\to\new\virtual\environment

The command, if run with ‘-h’, will show the available options:

     usage: venv [-h] [--system-site-packages] [--symlinks | --copies] [--clear]
                 [--upgrade] [--without-pip] [--prompt PROMPT] [--upgrade-deps]
                 [--without-scm-ignore-files]
                 ENV_DIR [ENV_DIR ...]

     Creates virtual Python environments in one or more target directories.

     Once an environment has been created, you may wish to activate it, e.g. by
     sourcing an activate script in its bin directory.

 -- Option: ENV_DIR

     A required argument specifying the directory to create the
     environment in.

 -- Option: --system-site-packages

     Give the virtual environment access to the system site-packages
     directory.

 -- Option: --symlinks

     Try to use symlinks rather than copies, when symlinks are not the
     default for the platform.

 -- Option: --copies

     Try to use copies rather than symlinks, even when symlinks are the
     default for the platform.

 -- Option: --clear

     Delete the contents of the environment directory if it already
     exists, before environment creation.

 -- Option: --upgrade

     Upgrade the environment directory to use this version of Python,
     assuming Python has been upgraded in-place.

 -- Option: --without-pip

     Skips installing or upgrading pip in the virtual environment (pip
     is bootstrapped by default).

 -- Option: --prompt <PROMPT>

     Provides an alternative prompt prefix for this environment.

 -- Option: --upgrade-deps

     Upgrade core dependencies (pip) to the latest version in PyPI.

 -- Option: --without-scm-ignore-files

     Skips adding SCM ignore files to the environment directory (Git is
     supported by default).

Changed in version 3.4: Installs pip by default, added the
‘--without-pip’ and ‘--copies’ options.

Changed in version 3.4: In earlier versions, if the target directory
already existed, an error was raised, unless the ‘--clear’ or
‘--upgrade’ option was provided.

Changed in version 3.9: Add ‘--upgrade-deps’ option to upgrade pip +
setuptools to the latest on PyPI.

Changed in version 3.12: ‘setuptools’ is no longer a core venv
dependency.

Changed in version 3.13: Added the ‘--without-scm-ignore-files’ option.

Changed in version 3.13: ‘venv’ now creates a ‘.gitignore’ file for Git
by default.

     Note: While symlinks are supported on Windows, they are not
     recommended.  Of particular note is that double-clicking
     ‘python.exe’ in File Explorer will resolve the symlink eagerly and
     ignore the virtual environment.

     Note: On Microsoft Windows, it may be required to enable the
     ‘Activate.ps1’ script by setting the execution policy for the user.
     You can do this by issuing the following PowerShell command:

          PS C:\> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

     See About Execution Policies(1) for more information.

The created ‘pyvenv.cfg’ file also includes the
‘include-system-site-packages’ key, set to ‘true’ if ‘venv’ is run with
the ‘--system-site-packages’ option, ‘false’ otherwise.

Unless the ‘--without-pip’ option is given, *note ensurepip: 55. will be
invoked to bootstrap ‘pip’ into the virtual environment.

Multiple paths can be given to ‘venv’, in which case an identical
virtual environment will be created, according to the given options, at
each provided path.

   ---------- Footnotes ----------

   (1) https://go.microsoft.com/fwlink/?LinkID=135170


File: python.info,  Node: How venvs work,  Next: API<2>,  Prev: Creating virtual environments,  Up: venv — Creation of virtual environments

5.28.2.2 How venvs work
.......................

When a Python interpreter is running from a virtual environment, *note
sys.prefix: 3b9. and *note sys.exec_prefix: 3b5. point to the
directories of the virtual environment, whereas *note sys.base_prefix:
3f2. and *note sys.base_exec_prefix: 3f1. point to those of the base
Python used to create the environment.  It is sufficient to check
‘sys.prefix != sys.base_prefix’ to determine if the current interpreter
is running from a virtual environment.

A virtual environment may be “activated” using a script in its binary
directory (‘bin’ on POSIX; ‘Scripts’ on Windows).  This will prepend
that directory to your ‘PATH’, so that running ‘python’ will invoke the
environment’s Python interpreter and you can run installed scripts
without having to use their full path.  The invocation of the activation
script is platform-specific (‘<VENV>’ must be replaced by the path to
the directory containing the virtual environment):

Platform          Shell            Command to activate virtual environment
                                   
------------------------------------------------------------------------------------------
                                   
POSIX             bash/zsh         ‘$ source <VENV>/bin/activate’
                                   
                  
fish              ‘$ source
                  <VENV>/bin/activate.fish’
                  
                  
csh/tcsh          ‘$ source
                  <VENV>/bin/activate.csh’
                  
                  
pwsh              ‘$
                  <VENV>/bin/Activate.ps1’
                  
                                   
Windows           cmd.exe          ‘C:\> <VENV>\Scripts\activate.bat’
                                   
                  
PowerShell        ‘PS C:\>
                  <VENV>\Scripts\Activate.ps1’
                  

Added in version 3.4: ‘fish’ and ‘csh’ activation scripts.

Added in version 3.8: PowerShell activation scripts installed under
POSIX for PowerShell Core support.

You don’t specifically 'need' to activate a virtual environment, as you
can just specify the full path to that environment’s Python interpreter
when invoking Python.  Furthermore, all scripts installed in the
environment should be runnable without activating it.

In order to achieve this, scripts installed into virtual environments
have a “shebang” line which points to the environment’s Python
interpreter, ‘#!/<PATH-TO-VENV>/bin/python’.  This means that the script
will run with that interpreter regardless of the value of ‘PATH’.  On
Windows, “shebang” line processing is supported if you have the *note
Python Launcher for Windows: 5c1. installed.  Thus, double-clicking an
installed script in a Windows Explorer window should run it with the
correct interpreter without the environment needing to be activated or
on the ‘PATH’.

When a virtual environment has been activated, the ‘VIRTUAL_ENV’
environment variable is set to the path of the environment.  Since
explicitly activating a virtual environment is not required to use it,
‘VIRTUAL_ENV’ cannot be relied upon to determine whether a virtual
environment is being used.

     Warning: Because scripts installed in environments should not
     expect the environment to be activated, their shebang lines contain
     the absolute paths to their environment’s interpreters.  Because of
     this, environments are inherently non-portable, in the general
     case.  You should always have a simple means of recreating an
     environment (for example, if you have a requirements file
     ‘requirements.txt’, you can invoke ‘pip install -r
     requirements.txt’ using the environment’s ‘pip’ to install all of
     the packages needed by the environment).  If for any reason you
     need to move the environment to a new location, you should recreate
     it at the desired location and delete the one at the old location.
     If you move an environment because you moved a parent directory of
     it, you should recreate the environment in its new location.
     Otherwise, software installed into the environment may not work as
     expected.

You can deactivate a virtual environment by typing ‘deactivate’ in your
shell.  The exact mechanism is platform-specific and is an internal
implementation detail (typically, a script or shell function will be
used).


File: python.info,  Node: API<2>,  Next: An example of extending EnvBuilder,  Prev: How venvs work,  Up: venv — Creation of virtual environments

5.28.2.3 API
............

The high-level method described above makes use of a simple API which
provides mechanisms for third-party virtual environment creators to
customize environment creation according to their needs, the *note
EnvBuilder: 26a. class.

 -- Class: venv.EnvBuilder (system_site_packages=False, clear=False,
          symlinks=False, upgrade=False, with_pip=False, prompt=None,
          upgrade_deps=False, *, scm_ignore_files=frozenset())

     The ‘EnvBuilder’ class accepts the following keyword arguments on
     instantiation:

        * 'system_site_packages' – a boolean value indicating that the
          system Python site-packages should be available to the
          environment (defaults to ‘False’).

        * 'clear' – a boolean value which, if true, will delete the
          contents of any existing target directory, before creating the
          environment.

        * 'symlinks' – a boolean value indicating whether to attempt to
          symlink the Python binary rather than copying.

        * 'upgrade' – a boolean value which, if true, will upgrade an
          existing environment with the running Python - for use when
          that Python has been upgraded in-place (defaults to ‘False’).

        * 'with_pip' – a boolean value which, if true, ensures pip is
          installed in the virtual environment.  This uses *note
          ensurepip: 55. with the ‘--default-pip’ option.

        * 'prompt' – a string to be used after virtual environment is
          activated (defaults to ‘None’ which means directory name of
          the environment would be used).  If the special string ‘"."’
          is provided, the basename of the current directory is used as
          the prompt.

        * 'upgrade_deps' – Update the base venv modules to the latest on
          PyPI

        * 'scm_ignore_files' – Create ignore files based for the
          specified source control managers (SCM) in the iterable.
          Support is defined by having a method named
          ‘create_{scm}_ignore_file’.  The only value supported by
          default is ‘"git"’ via *note create_git_ignore_file(): 4589.

     Changed in version 3.4: Added the ‘with_pip’ parameter

     Changed in version 3.6: Added the ‘prompt’ parameter

     Changed in version 3.9: Added the ‘upgrade_deps’ parameter

     Changed in version 3.13: Added the ‘scm_ignore_files’ parameter

     ‘EnvBuilder’ may be used as a base class.

      -- Method: create (env_dir)

          Create a virtual environment by specifying the target
          directory (absolute or relative to the current directory)
          which is to contain the virtual environment.  The ‘create’
          method will either create the environment in the specified
          directory, or raise an appropriate exception.

          The ‘create’ method of the ‘EnvBuilder’ class illustrates the
          hooks available for subclass customization:

               def create(self, env_dir):
                   """
                   Create a virtualized Python environment in a directory.
                   env_dir is the target directory to create an environment in.
                   """
                   env_dir = os.path.abspath(env_dir)
                   context = self.ensure_directories(env_dir)
                   self.create_configuration(context)
                   self.setup_python(context)
                   self.setup_scripts(context)
                   self.post_setup(context)

          Each of the methods *note ensure_directories(): 458b, *note
          create_configuration(): 458c, *note setup_python(): 458d,
          *note setup_scripts(): 458e. and *note post_setup(): 458f. can
          be overridden.

      -- Method: ensure_directories (env_dir)

          Creates the environment directory and all necessary
          subdirectories that don’t already exist, and returns a context
          object.  This context object is just a holder for attributes
          (such as paths) for use by the other methods.  If the
          ‘EnvBuilder’ is created with the arg ‘clear=True’, contents of
          the environment directory will be cleared and then all
          necessary subdirectories will be recreated.

          The returned context object is a *note types.SimpleNamespace:
          1d1. with the following attributes:

             * ‘env_dir’ - The location of the virtual environment.
               Used for ‘__VENV_DIR__’ in activation scripts (see *note
               install_scripts(): 4590.).

             * ‘env_name’ - The name of the virtual environment.  Used
               for ‘__VENV_NAME__’ in activation scripts (see *note
               install_scripts(): 4590.).

             * ‘prompt’ - The prompt to be used by the activation
               scripts.  Used for ‘__VENV_PROMPT__’ in activation
               scripts (see *note install_scripts(): 4590.).

             * ‘executable’ - The underlying Python executable used by
               the virtual environment.  This takes into account the
               case where a virtual environment is created from another
               virtual environment.

             * ‘inc_path’ - The include path for the virtual
               environment.

             * ‘lib_path’ - The purelib path for the virtual
               environment.

             * ‘bin_path’ - The script path for the virtual environment.

             * ‘bin_name’ - The name of the script path relative to the
               virtual environment location.  Used for
               ‘__VENV_BIN_NAME__’ in activation scripts (see *note
               install_scripts(): 4590.).

             * ‘env_exe’ - The name of the Python interpreter in the
               virtual environment.  Used for ‘__VENV_PYTHON__’ in
               activation scripts (see *note install_scripts(): 4590.).

             * ‘env_exec_cmd’ - The name of the Python interpreter,
               taking into account filesystem redirections.  This can be
               used to run Python in the virtual environment.

          Changed in version 3.11: The 'venv' *note sysconfig
          installation scheme: 692. is used to construct the paths of
          the created directories.

          Changed in version 3.12: The attribute ‘lib_path’ was added to
          the context, and the context object was documented.

      -- Method: create_configuration (context)

          Creates the ‘pyvenv.cfg’ configuration file in the
          environment.

      -- Method: setup_python (context)

          Creates a copy or symlink to the Python executable in the
          environment.  On POSIX systems, if a specific executable
          ‘python3.x’ was used, symlinks to ‘python’ and ‘python3’ will
          be created pointing to that executable, unless files with
          those names already exist.

      -- Method: setup_scripts (context)

          Installs activation scripts appropriate to the platform into
          the virtual environment.

      -- Method: upgrade_dependencies (context)

          Upgrades the core venv dependency packages (currently pip(1))
          in the environment.  This is done by shelling out to the ‘pip’
          executable in the environment.

          Added in version 3.9.

          Changed in version 3.12: setuptools(2) is no longer a core
          venv dependency.

      -- Method: post_setup (context)

          A placeholder method which can be overridden in third party
          implementations to pre-install packages in the virtual
          environment or perform other post-creation steps.

      -- Method: install_scripts (context, path)

          This method can be called from *note setup_scripts(): 458e. or
          *note post_setup(): 458f. in subclasses to assist in
          installing custom scripts into the virtual environment.

          'path' is the path to a directory that should contain
          subdirectories ‘common’, ‘posix’, ‘nt’; each containing
          scripts destined for the ‘bin’ directory in the environment.
          The contents of ‘common’ and the directory corresponding to
          *note os.name: 2d00. are copied after some text replacement of
          placeholders:

             * ‘__VENV_DIR__’ is replaced with the absolute path of the
               environment directory.

             * ‘__VENV_NAME__’ is replaced with the environment name
               (final path segment of environment directory).

             * ‘__VENV_PROMPT__’ is replaced with the prompt (the
               environment name surrounded by parentheses and with a
               following space)

             * ‘__VENV_BIN_NAME__’ is replaced with the name of the bin
               directory (either ‘bin’ or ‘Scripts’).

             * ‘__VENV_PYTHON__’ is replaced with the absolute path of
               the environment’s executable.

          The directories are allowed to exist (for when an existing
          environment is being upgraded).

      -- Method: create_git_ignore_file (context)

          Creates a ‘.gitignore’ file within the virtual environment
          that causes the entire directory to be ignored by the Git
          source control manager.

          Added in version 3.13.

     Changed in version 3.7.2: Windows now uses redirector scripts for
     ‘python[w].exe’ instead of copying the actual binaries.  In 3.7.2
     only *note setup_python(): 458d. does nothing unless running from a
     build in the source tree.

     Changed in version 3.7.3: Windows copies the redirector scripts as
     part of *note setup_python(): 458d. instead of *note
     setup_scripts(): 458e.  This was not the case in 3.7.2.  When using
     symlinks, the original executables will be linked.

There is also a module-level convenience function:

 -- Function: venv.create (env_dir, system_site_packages=False,
          clear=False, symlinks=False, with_pip=False, prompt=None,
          upgrade_deps=False, *, scm_ignore_files=frozenset())

     Create an *note EnvBuilder: 26a. with the given keyword arguments,
     and call its *note create(): 458a. method with the 'env_dir'
     argument.

     Added in version 3.3.

     Changed in version 3.4: Added the 'with_pip' parameter

     Changed in version 3.6: Added the 'prompt' parameter

     Changed in version 3.9: Added the 'upgrade_deps' parameter

     Changed in version 3.13: Added the 'scm_ignore_files' parameter

   ---------- Footnotes ----------

   (1) https://pypi.org/project/pip/

   (2) https://pypi.org/project/setuptools/


File: python.info,  Node: An example of extending EnvBuilder,  Prev: API<2>,  Up: venv — Creation of virtual environments

5.28.2.4 An example of extending ‘EnvBuilder’
.............................................

The following script shows how to extend *note EnvBuilder: 26a. by
implementing a subclass which installs setuptools and pip into a created
virtual environment:

     import os
     import os.path
     from subprocess import Popen, PIPE
     import sys
     from threading import Thread
     from urllib.parse import urlsplit
     from urllib.request import urlretrieve
     import venv

     class ExtendedEnvBuilder(venv.EnvBuilder):
         """
         This builder installs setuptools and pip so that you can pip or
         easy_install other packages into the created virtual environment.

         :param nodist: If true, setuptools and pip are not installed into the
                        created virtual environment.
         :param nopip: If true, pip is not installed into the created
                       virtual environment.
         :param progress: If setuptools or pip are installed, the progress of the
                          installation can be monitored by passing a progress
                          callable. If specified, it is called with two
                          arguments: a string indicating some progress, and a
                          context indicating where the string is coming from.
                          The context argument can have one of three values:
                          'main', indicating that it is called from virtualize()
                          itself, and 'stdout' and 'stderr', which are obtained
                          by reading lines from the output streams of a subprocess
                          which is used to install the app.

                          If a callable is not specified, default progress
                          information is output to sys.stderr.
         """

         def __init__(self, *args, **kwargs):
             self.nodist = kwargs.pop('nodist', False)
             self.nopip = kwargs.pop('nopip', False)
             self.progress = kwargs.pop('progress', None)
             self.verbose = kwargs.pop('verbose', False)
             super().__init__(*args, **kwargs)

         def post_setup(self, context):
             """
             Set up any packages which need to be pre-installed into the
             virtual environment being created.

             :param context: The information for the virtual environment
                             creation request being processed.
             """
             os.environ['VIRTUAL_ENV'] = context.env_dir
             if not self.nodist:
                 self.install_setuptools(context)
             # Can't install pip without setuptools
             if not self.nopip and not self.nodist:
                 self.install_pip(context)

         def reader(self, stream, context):
             """
             Read lines from a subprocess' output stream and either pass to a progress
             callable (if specified) or write progress information to sys.stderr.
             """
             progress = self.progress
             while True:
                 s = stream.readline()
                 if not s:
                     break
                 if progress is not None:
                     progress(s, context)
                 else:
                     if not self.verbose:
                         sys.stderr.write('.')
                     else:
                         sys.stderr.write(s.decode('utf-8'))
                     sys.stderr.flush()
             stream.close()

         def install_script(self, context, name, url):
             _, _, path, _, _ = urlsplit(url)
             fn = os.path.split(path)[-1]
             binpath = context.bin_path
             distpath = os.path.join(binpath, fn)
             # Download script into the virtual environment's binaries folder
             urlretrieve(url, distpath)
             progress = self.progress
             if self.verbose:
                 term = '\n'
             else:
                 term = ''
             if progress is not None:
                 progress('Installing %s ...%s' % (name, term), 'main')
             else:
                 sys.stderr.write('Installing %s ...%s' % (name, term))
                 sys.stderr.flush()
             # Install in the virtual environment
             args = [context.env_exe, fn]
             p = Popen(args, stdout=PIPE, stderr=PIPE, cwd=binpath)
             t1 = Thread(target=self.reader, args=(p.stdout, 'stdout'))
             t1.start()
             t2 = Thread(target=self.reader, args=(p.stderr, 'stderr'))
             t2.start()
             p.wait()
             t1.join()
             t2.join()
             if progress is not None:
                 progress('done.', 'main')
             else:
                 sys.stderr.write('done.\n')
             # Clean up - no longer needed
             os.unlink(distpath)

         def install_setuptools(self, context):
             """
             Install setuptools in the virtual environment.

             :param context: The information for the virtual environment
                             creation request being processed.
             """
             url = "https://bootstrap.pypa.io/ez_setup.py"
             self.install_script(context, 'setuptools', url)
             # clear up the setuptools archive which gets downloaded
             pred = lambda o: o.startswith('setuptools-') and o.endswith('.tar.gz')
             files = filter(pred, os.listdir(context.bin_path))
             for f in files:
                 f = os.path.join(context.bin_path, f)
                 os.unlink(f)

         def install_pip(self, context):
             """
             Install pip in the virtual environment.

             :param context: The information for the virtual environment
                             creation request being processed.
             """
             url = 'https://bootstrap.pypa.io/get-pip.py'
             self.install_script(context, 'pip', url)


     def main(args=None):
         import argparse

         parser = argparse.ArgumentParser(prog=__name__,
                                          description='Creates virtual Python '
                                                      'environments in one or '
                                                      'more target '
                                                      'directories.')
         parser.add_argument('dirs', metavar='ENV_DIR', nargs='+',
                             help='A directory in which to create the '
                                  'virtual environment.')
         parser.add_argument('--no-setuptools', default=False,
                             action='store_true', dest='nodist',
                             help="Don't install setuptools or pip in the "
                                  "virtual environment.")
         parser.add_argument('--no-pip', default=False,
                             action='store_true', dest='nopip',
                             help="Don't install pip in the virtual "
                                  "environment.")
         parser.add_argument('--system-site-packages', default=False,
                             action='store_true', dest='system_site',
                             help='Give the virtual environment access to the '
                                  'system site-packages dir.')
         if os.name == 'nt':
             use_symlinks = False
         else:
             use_symlinks = True
         parser.add_argument('--symlinks', default=use_symlinks,
                             action='store_true', dest='symlinks',
                             help='Try to use symlinks rather than copies, '
                                  'when symlinks are not the default for '
                                  'the platform.')
         parser.add_argument('--clear', default=False, action='store_true',
                             dest='clear', help='Delete the contents of the '
                                                'virtual environment '
                                                'directory if it already '
                                                'exists, before virtual '
                                                'environment creation.')
         parser.add_argument('--upgrade', default=False, action='store_true',
                             dest='upgrade', help='Upgrade the virtual '
                                                  'environment directory to '
                                                  'use this version of '
                                                  'Python, assuming Python '
                                                  'has been upgraded '
                                                  'in-place.')
         parser.add_argument('--verbose', default=False, action='store_true',
                             dest='verbose', help='Display the output '
                                                  'from the scripts which '
                                                  'install setuptools and pip.')
         options = parser.parse_args(args)
         if options.upgrade and options.clear:
             raise ValueError('you cannot supply --upgrade and --clear together.')
         builder = ExtendedEnvBuilder(system_site_packages=options.system_site,
                                        clear=options.clear,
                                        symlinks=options.symlinks,
                                        upgrade=options.upgrade,
                                        nodist=options.nodist,
                                        nopip=options.nopip,
                                        verbose=options.verbose)
         for d in options.dirs:
             builder.create(d)

     if __name__ == '__main__':
         rc = 1
         try:
             main()
             rc = 0
         except Exception as e:
             print('Error: %s' % e, file=sys.stderr)
         sys.exit(rc)

This script is also available for download online(1).

   ---------- Footnotes ----------

   (1) https://gist.github.com/vsajip/4673395


File: python.info,  Node: zipapp — Manage executable Python zip archives,  Prev: venv — Creation of virtual environments,  Up: Software Packaging and Distribution

5.28.3 ‘zipapp’ — Manage executable Python zip archives
-------------------------------------------------------

Added in version 3.5.

'Source code:' Lib/zipapp.py(1)

__________________________________________________________________

This module provides tools to manage the creation of zip files
containing Python code, which can be *note executed directly by the
Python interpreter: 1ed2.  The module provides both a *note Command-Line
Interface: 4596. and a *note Python API: 4597.

* Menu:

* Basic Example::
* Command-Line Interface: Command-Line Interface<4>.
* Python API::
* Examples: Examples<32>.
* Specifying the Interpreter::
* Creating Standalone Applications with zipapp::
* The Python Zip Application Archive Format::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/zipapp.py


File: python.info,  Node: Basic Example,  Next: Command-Line Interface<4>,  Up: zipapp — Manage executable Python zip archives

5.28.3.1 Basic Example
......................

The following example shows how the *note Command-Line Interface: 4596.
can be used to create an executable archive from a directory containing
Python code.  When run, the archive will execute the ‘main’ function
from the module ‘myapp’ in the archive.

     $ python -m zipapp myapp -m "myapp:main"
     $ python myapp.pyz
     <output from myapp>


File: python.info,  Node: Command-Line Interface<4>,  Next: Python API,  Prev: Basic Example,  Up: zipapp — Manage executable Python zip archives

5.28.3.2 Command-Line Interface
...............................

When called as a program from the command line, the following form is
used:

     $ python -m zipapp source [options]

If 'source' is a directory, this will create an archive from the
contents of 'source'.  If 'source' is a file, it should be an archive,
and it will be copied to the target archive (or the contents of its
shebang line will be displayed if the –info option is specified).

The following options are understood:

 -- Option: -o <output>, --output=<output>

     Write the output to a file named 'output'.  If this option is not
     specified, the output filename will be the same as the input
     'source', with the extension ‘.pyz’ added.  If an explicit filename
     is given, it is used as is (so a ‘.pyz’ extension should be
     included if required).

     An output filename must be specified if the 'source' is an archive
     (and in that case, 'output' must not be the same as 'source').

 -- Option: -p <interpreter>, --python=<interpreter>

     Add a ‘#!’ line to the archive specifying 'interpreter' as the
     command to run.  Also, on POSIX, make the archive executable.  The
     default is to write no ‘#!’ line, and not make the file executable.

 -- Option: -m <mainfn>, --main=<mainfn>

     Write a ‘__main__.py’ file to the archive that executes 'mainfn'.
     The 'mainfn' argument should have the form “pkg.mod:fn”, where
     “pkg.mod” is a package/module in the archive, and “fn” is a
     callable in the given module.  The ‘__main__.py’ file will execute
     that callable.

     *note -main: 459e. cannot be specified when copying an archive.

 -- Option: -c, --compress

     Compress files with the deflate method, reducing the size of the
     output file.  By default, files are stored uncompressed in the
     archive.

     *note -compress: 45a0. has no effect when copying an archive.

     Added in version 3.7.

 -- Option: --info

     Display the interpreter embedded in the archive, for diagnostic
     purposes.  In this case, any other options are ignored and SOURCE
     must be an archive, not a directory.

 -- Option: -h, --help

     Print a short usage message and exit.


File: python.info,  Node: Python API,  Next: Examples<32>,  Prev: Command-Line Interface<4>,  Up: zipapp — Manage executable Python zip archives

5.28.3.3 Python API
...................

The module defines two convenience functions:

 -- Function: zipapp.create_archive (source, target=None,
          interpreter=None, main=None, filter=None, compressed=False)

     Create an application archive from 'source'.  The source can be any
     of the following:

        * The name of a directory, or a *note path-like object: 2a0.
          referring to a directory, in which case a new application
          archive will be created from the content of that directory.

        * The name of an existing application archive file, or a *note
          path-like object: 2a0. referring to such a file, in which case
          the file is copied to the target (modifying it to reflect the
          value given for the 'interpreter' argument).  The file name
          should include the ‘.pyz’ extension, if required.

        * A file object open for reading in bytes mode.  The content of
          the file should be an application archive, and the file object
          is assumed to be positioned at the start of the archive.

     The 'target' argument determines where the resulting archive will
     be written:

        * If it is the name of a file, or a *note path-like object: 2a0,
          the archive will be written to that file.

        * If it is an open file object, the archive will be written to
          that file object, which must be open for writing in bytes
          mode.

        * If the target is omitted (or ‘None’), the source must be a
          directory and the target will be a file with the same name as
          the source, with a ‘.pyz’ extension added.

     The 'interpreter' argument specifies the name of the Python
     interpreter with which the archive will be executed.  It is written
     as a “shebang” line at the start of the archive.  On POSIX, this
     will be interpreted by the OS, and on Windows it will be handled by
     the Python launcher.  Omitting the 'interpreter' results in no
     shebang line being written.  If an interpreter is specified, and
     the target is a filename, the executable bit of the target file
     will be set.

     The 'main' argument specifies the name of a callable which will be
     used as the main program for the archive.  It can only be specified
     if the source is a directory, and the source does not already
     contain a ‘__main__.py’ file.  The 'main' argument should take the
     form “pkg.module:callable” and the archive will be run by importing
     “pkg.module” and executing the given callable with no arguments.
     It is an error to omit 'main' if the source is a directory and does
     not contain a ‘__main__.py’ file, as otherwise the resulting
     archive would not be executable.

     The optional 'filter' argument specifies a callback function that
     is passed a Path object representing the path to the file being
     added (relative to the source directory).  It should return ‘True’
     if the file is to be added.

     The optional 'compressed' argument determines whether files are
     compressed.  If set to ‘True’, files in the archive are compressed
     with the deflate method; otherwise, files are stored uncompressed.
     This argument has no effect when copying an existing archive.

     If a file object is specified for 'source' or 'target', it is the
     caller’s responsibility to close it after calling create_archive.

     When copying an existing archive, file objects supplied only need
     ‘read’ and ‘readline’, or ‘write’ methods.  When creating an
     archive from a directory, if the target is a file object it will be
     passed to the ‘zipfile.ZipFile’ class, and must supply the methods
     needed by that class.

     Changed in version 3.7: Added the 'filter' and 'compressed'
     parameters.

 -- Function: zipapp.get_interpreter (archive)

     Return the interpreter specified in the ‘#!’ line at the start of
     the archive.  If there is no ‘#!’ line, return *note None: 678.
     The 'archive' argument can be a filename or a file-like object open
     for reading in bytes mode.  It is assumed to be at the start of the
     archive.


File: python.info,  Node: Examples<32>,  Next: Specifying the Interpreter,  Prev: Python API,  Up: zipapp — Manage executable Python zip archives

5.28.3.4 Examples
.................

Pack up a directory into an archive, and run it.

     $ python -m zipapp myapp
     $ python myapp.pyz
     <output from myapp>

The same can be done using the *note create_archive(): bce. function:

     >>> import zipapp
     >>> zipapp.create_archive('myapp', 'myapp.pyz')

To make the application directly executable on POSIX, specify an
interpreter to use.

     $ python -m zipapp myapp -p "/usr/bin/env python"
     $ ./myapp.pyz
     <output from myapp>

To replace the shebang line on an existing archive, create a modified
archive using the *note create_archive(): bce. function:

     >>> import zipapp
     >>> zipapp.create_archive('old_archive.pyz', 'new_archive.pyz', '/usr/bin/python3')

To update the file in place, do the replacement in memory using a *note
BytesIO: ed8. object, and then overwrite the source afterwards.  Note
that there is a risk when overwriting a file in place that an error will
result in the loss of the original file.  This code does not protect
against such errors, but production code should do so.  Also, this
method will only work if the archive fits in memory:

     >>> import zipapp
     >>> import io
     >>> temp = io.BytesIO()
     >>> zipapp.create_archive('myapp.pyz', temp, '/usr/bin/python2')
     >>> with open('myapp.pyz', 'wb') as f:
     >>>     f.write(temp.getvalue())


File: python.info,  Node: Specifying the Interpreter,  Next: Creating Standalone Applications with zipapp,  Prev: Examples<32>,  Up: zipapp — Manage executable Python zip archives

5.28.3.5 Specifying the Interpreter
...................................

Note that if you specify an interpreter and then distribute your
application archive, you need to ensure that the interpreter used is
portable.  The Python launcher for Windows supports most common forms of
POSIX ‘#!’ line, but there are other issues to consider:

   * If you use “/usr/bin/env python” (or other forms of the “python”
     command, such as “/usr/bin/python”), you need to consider that your
     users may have either Python 2 or Python 3 as their default, and
     write your code to work under both versions.

   * If you use an explicit version, for example “/usr/bin/env python3”
     your application will not work for users who do not have that
     version.  (This may be what you want if you have not made your code
     Python 2 compatible).

   * There is no way to say “python X.Y or later”, so be careful of
     using an exact version like “/usr/bin/env python3.4” as you will
     need to change your shebang line for users of Python 3.5, for
     example.

Typically, you should use an “/usr/bin/env python2” or “/usr/bin/env
python3”, depending on whether your code is written for Python 2 or 3.


File: python.info,  Node: Creating Standalone Applications with zipapp,  Next: The Python Zip Application Archive Format,  Prev: Specifying the Interpreter,  Up: zipapp — Manage executable Python zip archives

5.28.3.6 Creating Standalone Applications with zipapp
.....................................................

Using the ‘zipapp’ module, it is possible to create self-contained
Python programs, which can be distributed to end users who only need to
have a suitable version of Python installed on their system.  The key to
doing this is to bundle all of the application’s dependencies into the
archive, along with the application code.

The steps to create a standalone archive are as follows:

  1. Create your application in a directory as normal, so you have a
     ‘myapp’ directory containing a ‘__main__.py’ file, and any
     supporting application code.

  2. Install all of your application’s dependencies into the ‘myapp’
     directory, using pip:

          $ python -m pip install -r requirements.txt --target myapp

     (this assumes you have your project requirements in a
     ‘requirements.txt’ file - if not, you can just list the
     dependencies manually on the pip command line).

  3. Package the application using:

          $ python -m zipapp -p "interpreter" myapp

This will produce a standalone executable, which can be run on any
machine with the appropriate interpreter available.  See *note
Specifying the Interpreter: 45aa. for details.  It can be shipped to
users as a single file.

On Unix, the ‘myapp.pyz’ file is executable as it stands.  You can
rename the file to remove the ‘.pyz’ extension if you prefer a “plain”
command name.  On Windows, the ‘myapp.pyz[w]’ file is executable by
virtue of the fact that the Python interpreter registers the ‘.pyz’ and
‘.pyzw’ file extensions when installed.

* Menu:

* Caveats::


File: python.info,  Node: Caveats,  Up: Creating Standalone Applications with zipapp

5.28.3.7 Caveats
................

If your application depends on a package that includes a C extension,
that package cannot be run from a zip file (this is an OS limitation, as
executable code must be present in the filesystem for the OS loader to
load it).  In this case, you can exclude that dependency from the
zipfile, and either require your users to have it installed, or ship it
alongside your zipfile and add code to your ‘__main__.py’ to include the
directory containing the unzipped module in ‘sys.path’.  In this case,
you will need to make sure to ship appropriate binaries for your target
architecture(s) (and potentially pick the correct version to add to
‘sys.path’ at runtime, based on the user’s machine).


File: python.info,  Node: The Python Zip Application Archive Format,  Prev: Creating Standalone Applications with zipapp,  Up: zipapp — Manage executable Python zip archives

5.28.3.8 The Python Zip Application Archive Format
..................................................

Python has been able to execute zip files which contain a ‘__main__.py’
file since version 2.6.  In order to be executed by Python, an
application archive simply has to be a standard zip file containing a
‘__main__.py’ file which will be run as the entry point for the
application.  As usual for any Python script, the parent of the script
(in this case the zip file) will be placed on *note sys.path: 3b7. and
thus further modules can be imported from the zip file.

The zip file format allows arbitrary data to be prepended to a zip file.
The zip application format uses this ability to prepend a standard POSIX
“shebang” line to the file (‘#!/path/to/interpreter’).

Formally, the Python zip application format is therefore:

  1. An optional shebang line, containing the characters ‘b'#!'’
     followed by an interpreter name, and then a newline (‘b'\n'’)
     character.  The interpreter name can be anything acceptable to the
     OS “shebang” processing, or the Python launcher on Windows.  The
     interpreter should be encoded in UTF-8 on Windows, and in *note
     sys.getfilesystemencoding(): c7a. on POSIX.

  2. Standard zipfile data, as generated by the *note zipfile: 131.
     module.  The zipfile content 'must' include a file called
     ‘__main__.py’ (which must be in the “root” of the zipfile - i.e.,
     it cannot be in a subdirectory).  The zipfile data can be
     compressed or uncompressed.

If an application archive has a shebang line, it may have the executable
bit set on POSIX systems, to allow it to be executed directly.

There is no requirement that the tools in this module are used to create
application archives - the module is a convenience, but archives in the
above format created by any means are acceptable to Python.


File: python.info,  Node: Python Runtime Services,  Next: Custom Python Interpreters,  Prev: Software Packaging and Distribution,  Up: The Python Standard Library

5.29 Python Runtime Services
============================

The modules described in this chapter provide a wide range of services
related to the Python interpreter and its interaction with its
environment.  Here’s an overview:

* Menu:

* sys — System-specific parameters and functions::
* sys.monitoring — Execution event monitoring: sys monitoring — Execution event monitoring.
* sysconfig — Provide access to Python’s configuration information::
* builtins — Built-in objects::
* __main__ — Top-level code environment::
* warnings — Warning control::
* dataclasses — Data Classes::
* contextlib — Utilities for with-statement contexts::
* abc — Abstract Base Classes::
* atexit — Exit handlers::
* traceback — Print or retrieve a stack traceback::
* __future__ — Future statement definitions::
* gc — Garbage Collector interface::
* inspect — Inspect live objects::
* site — Site-specific configuration hook::


File: python.info,  Node: sys — System-specific parameters and functions,  Next: sys monitoring — Execution event monitoring,  Up: Python Runtime Services

5.29.1 ‘sys’ — System-specific parameters and functions
-------------------------------------------------------

__________________________________________________________________

This module provides access to some variables used or maintained by the
interpreter and to functions that interact strongly with the
interpreter.  It is always available.  Unless explicitly noted
otherwise, all variables are read-only.

 -- Data: sys.abiflags

     On POSIX systems where Python was built with the standard
     ‘configure’ script, this contains the ABI flags as specified by PEP
     3149(1).

     Added in version 3.2.

     Changed in version 3.8: Default flags became an empty string (‘m’
     flag for pymalloc has been removed).

     *note Availability: 1ef7.: Unix.

 -- Function: sys.addaudithook (hook)

     Append the callable 'hook' to the list of active auditing hooks for
     the current (sub)interpreter.

     When an auditing event is raised through the *note sys.audit():
     16be. function, each hook will be called in the order it was added
     with the event name and the tuple of arguments.  Native hooks added
     by *note PySys_AddAuditHook(): 441f. are called first, followed by
     hooks added in the current (sub)interpreter.  Hooks can then log
     the event, raise an exception to abort the operation, or terminate
     the process entirely.

     Note that audit hooks are primarily for collecting information
     about internal or otherwise unobservable actions, whether by Python
     or libraries written in Python.  They are not suitable for
     implementing a “sandbox”.  In particular, malicious code can
     trivially disable or bypass hooks added using this function.  At a
     minimum, any security-sensitive hooks must be added using the C API
     *note PySys_AddAuditHook(): 441f. before initialising the runtime,
     and any modules allowing arbitrary memory modification (such as
     *note ctypes: 2a.) should be completely removed or closely
     monitored.

     Calling *note sys.addaudithook(): 441e. will itself raise an
     auditing event named ‘sys.addaudithook’ with no arguments.  If any
     existing hooks raise an exception derived from *note RuntimeError:
     195, the new hook will not be added and the exception suppressed.
     As a result, callers cannot assume that their hook has been added
     unless they control all existing hooks.

     See the *note audit events table: 19b7. for all events raised by
     CPython, and PEP 578(2) for the original design discussion.

     Added in version 3.8.

     Changed in version 3.8.1: Exceptions derived from *note Exception:
     9e5. but not *note RuntimeError: 195. are no longer suppressed.

     'CPython implementation detail:' When tracing is enabled (see *note
     settrace(): 154e.), Python hooks are only traced if the callable
     has a ‘__cantrace__’ member that is set to a true value.
     Otherwise, trace functions will skip the hook.

 -- Data: sys.argv

     The list of command line arguments passed to a Python script.
     ‘argv[0]’ is the script name (it is operating system dependent
     whether this is a full pathname or not).  If the command was
     executed using the *note -c: 5e3. command line option to the
     interpreter, ‘argv[0]’ is set to the string ‘'-c'’.  If no script
     name was passed to the Python interpreter, ‘argv[0]’ is the empty
     string.

     To loop over the standard input, or the list of files given on the
     command line, see the *note fileinput: 5b. module.

     See also *note sys.orig_argv: 846.

          Note: On Unix, command line arguments are passed by bytes from
          OS. Python decodes them with filesystem encoding and
          “surrogateescape” error handler.  When you need original
          bytes, you can get it by ‘[os.fsencode(arg) for arg in
          sys.argv]’.

 -- Function: sys.audit (event, *args)

     Raise an auditing event and trigger any active auditing hooks.
     'event' is a string identifying the event, and 'args' may contain
     optional arguments with more information about the event.  The
     number and types of arguments for a given event are considered a
     public and stable API and should not be modified between releases.

     For example, one auditing event is named ‘os.chdir’.  This event
     has one argument called 'path' that will contain the requested new
     working directory.

     *note sys.audit(): 16be. will call the existing auditing hooks,
     passing the event name and arguments, and will re-raise the first
     exception from any hook.  In general, if an exception is raised, it
     should not be handled and the process should be terminated as
     quickly as possible.  This allows hook implementations to decide
     how to respond to particular events: they can merely log the event
     or abort the operation by raising an exception.

     Hooks are added using the *note sys.addaudithook(): 441e. or *note
     PySys_AddAuditHook(): 441f. functions.

     The native equivalent of this function is *note PySys_Audit(): 372.
     Using the native function is preferred when possible.

     See the *note audit events table: 19b7. for all events raised by
     CPython.

     Added in version 3.8.

 -- Data: sys.base_exec_prefix

     Set during Python startup, before ‘site.py’ is run, to the same
     value as *note exec_prefix: 3b5.  If not running in a *note virtual
     environment: 4579, the values will stay the same; if ‘site.py’
     finds that a virtual environment is in use, the values of *note
     prefix: 3b9. and ‘exec_prefix’ will be changed to point to the
     virtual environment, whereas *note base_prefix: 3f2. and
     ‘base_exec_prefix’ will remain pointing to the base Python
     installation (the one which the virtual environment was created
     from).

     Added in version 3.3.

 -- Data: sys.base_prefix

     Set during Python startup, before ‘site.py’ is run, to the same
     value as *note prefix: 3b9.  If not running in a *note virtual
     environment: 4579, the values will stay the same; if ‘site.py’
     finds that a virtual environment is in use, the values of ‘prefix’
     and *note exec_prefix: 3b5. will be changed to point to the virtual
     environment, whereas ‘base_prefix’ and *note base_exec_prefix: 3f1.
     will remain pointing to the base Python installation (the one which
     the virtual environment was created from).

     Added in version 3.3.

 -- Data: sys.byteorder

     An indicator of the native byte order.  This will have the value
     ‘'big'’ on big-endian (most-significant byte first) platforms, and
     ‘'little'’ on little-endian (least-significant byte first)
     platforms.

 -- Data: sys.builtin_module_names

     A tuple of strings containing the names of all modules that are
     compiled into this Python interpreter.  (This information is not
     available in any other way — ‘modules.keys()’ only lists the
     imported modules.)

     See also the *note sys.stdlib_module_names: 847. list.

 -- Function: sys.call_tracing (func, args)

     Call ‘func(*args)’, while tracing is enabled.  The tracing state is
     saved, and restored afterwards.  This is intended to be called from
     a debugger from a checkpoint, to recursively debug or profile some
     other code.

     Tracing is suspended while calling a tracing function set by *note
     settrace(): 154e. or *note setprofile(): 154d. to avoid infinite
     recursion.  ‘call_tracing()’ enables explicit recursion of the
     tracing function.

 -- Data: sys.copyright

     A string containing the copyright pertaining to the Python
     interpreter.

 -- Function: sys._clear_type_cache ()

     Clear the internal type cache.  The type cache is used to speed up
     attribute and method lookups.  Use the function 'only' to drop
     unnecessary references during reference leak debugging.

     This function should be used for internal and specialized purposes
     only.

     Deprecated since version 3.13: Use the more general *note
     _clear_internal_caches(): 1783. function instead.

 -- Function: sys._clear_internal_caches ()

     Clear all internal performance-related caches.  Use this function
     'only' to release unnecessary references and memory blocks when
     hunting for leaks.

     Added in version 3.13.

 -- Function: sys._current_frames ()

     Return a dictionary mapping each thread’s identifier to the topmost
     stack frame currently active in that thread at the time the
     function is called.  Note that functions in the *note traceback:
     fe. module can build the call stack given such a frame.

     This is most useful for debugging deadlock: this function does not
     require the deadlocked threads’ cooperation, and such threads’ call
     stacks are frozen for as long as they remain deadlocked.  The frame
     returned for a non-deadlocked thread may bear no relationship to
     that thread’s current activity by the time calling code examines
     the frame.

     This function should be used for internal and specialized purposes
     only.

     Raises an *note auditing event: 1a15. ‘sys._current_frames’ with no
     arguments.

 -- Function: sys._current_exceptions ()

     Return a dictionary mapping each thread’s identifier to the topmost
     exception currently active in that thread at the time the function
     is called.  If a thread is not currently handling an exception, it
     is not included in the result dictionary.

     This is most useful for statistical profiling.

     This function should be used for internal and specialized purposes
     only.

     Raises an *note auditing event: 1a15. ‘sys._current_exceptions’
     with no arguments.

     Changed in version 3.12: Each value in the dictionary is now a
     single exception instance, rather than a 3-tuple as returned from
     ‘sys.exc_info()’.

 -- Function: sys.breakpointhook ()

     This hook function is called by built-in *note breakpoint(): 234.
     By default, it drops you into the *note pdb: a5. debugger, but it
     can be set to any other function so that you can choose which
     debugger gets used.

     The signature of this function is dependent on what it calls.  For
     example, the default binding (e.g.  ‘pdb.set_trace()’) expects no
     arguments, but you might bind it to a function that expects
     additional arguments (positional and/or keyword).  The built-in
     ‘breakpoint()’ function passes its ‘*args’ and ‘**kws’ straight
     through.  Whatever ‘breakpointhooks()’ returns is returned from
     ‘breakpoint()’.

     The default implementation first consults the environment variable
     *note PYTHONBREAKPOINT: af1.  If that is set to ‘"0"’ then this
     function returns immediately; i.e.  it is a no-op.  If the
     environment variable is not set, or is set to the empty string,
     ‘pdb.set_trace()’ is called.  Otherwise this variable should name a
     function to run, using Python’s dotted-import nomenclature, e.g.
     ‘package.subpackage.module.function’.  In this case,
     ‘package.subpackage.module’ would be imported and the resulting
     module must have a callable named ‘function()’.  This is run,
     passing in ‘*args’ and ‘**kws’, and whatever ‘function()’ returns,
     ‘sys.breakpointhook()’ returns to the built-in *note breakpoint():
     234. function.

     Note that if anything goes wrong while importing the callable named
     by *note PYTHONBREAKPOINT: af1, a *note RuntimeWarning: 1bd. is
     reported and the breakpoint is ignored.

     Also note that if ‘sys.breakpointhook()’ is overridden
     programmatically, *note PYTHONBREAKPOINT: af1. is 'not' consulted.

     Added in version 3.7.

 -- Function: sys._debugmallocstats ()

     Print low-level information to stderr about the state of CPython’s
     memory allocator.

     If Python is *note built in debug mode: 1f9. (*note configure
     -with-pydebug option: 427.), it also performs some expensive
     internal consistency checks.

     Added in version 3.3.

     'CPython implementation detail:' This function is specific to
     CPython.  The exact output format is not defined here, and may
     change.

 -- Data: sys.dllhandle

     Integer specifying the handle of the Python DLL.

     *note Availability: 1ef7.: Windows.

 -- Function: sys.displayhook (value)

     If 'value' is not ‘None’, this function prints ‘repr(value)’ to
     ‘sys.stdout’, and saves 'value' in ‘builtins._’.  If ‘repr(value)’
     is not encodable to ‘sys.stdout.encoding’ with ‘sys.stdout.errors’
     error handler (which is probably ‘'strict'’), encode it to
     ‘sys.stdout.encoding’ with ‘'backslashreplace'’ error handler.

     ‘sys.displayhook’ is called on the result of evaluating an *note
     expression: 2135. entered in an interactive Python session.  The
     display of these values can be customized by assigning another
     one-argument function to ‘sys.displayhook’.

     Pseudo-code:

          def displayhook(value):
              if value is None:
                  return
              # Set '_' to None to avoid recursion
              builtins._ = None
              text = repr(value)
              try:
                  sys.stdout.write(text)
              except UnicodeEncodeError:
                  bytes = text.encode(sys.stdout.encoding, 'backslashreplace')
                  if hasattr(sys.stdout, 'buffer'):
                      sys.stdout.buffer.write(bytes)
                  else:
                      text = bytes.decode(sys.stdout.encoding, 'strict')
                      sys.stdout.write(text)
              sys.stdout.write("\n")
              builtins._ = value

     Changed in version 3.2: Use ‘'backslashreplace'’ error handler on
     *note UnicodeEncodeError: 67a.

 -- Data: sys.dont_write_bytecode

     If this is true, Python won’t try to write ‘.pyc’ files on the
     import of source modules.  This value is initially set to ‘True’ or
     ‘False’ depending on the *note -B: 141b. command line option and
     the *note PYTHONDONTWRITEBYTECODE: 141c. environment variable, but
     you can set it yourself to control bytecode file generation.

 -- Data: sys._emscripten_info

     A *note named tuple: 651. holding information about the environment
     on the 'wasm32-emscripten' platform.  The named tuple is
     provisional and may change in the future.

      -- Attribute: _emscripten_info.emscripten_version

          Emscripten version as tuple of ints (major, minor, micro),
          e.g.  ‘(3, 1, 8)’.

      -- Attribute: _emscripten_info.runtime

          Runtime string, e.g.  browser user agent, ‘'Node.js
          v14.18.2'’, or ‘'UNKNOWN'’.

      -- Attribute: _emscripten_info.pthreads

          ‘True’ if Python is compiled with Emscripten pthreads support.

      -- Attribute: _emscripten_info.shared_memory

          ‘True’ if Python is compiled with shared memory support.

     *note Availability: 1ef7.: Emscripten.

     Added in version 3.11.

 -- Data: sys.pycache_prefix

     If this is set (not ‘None’), Python will write bytecode-cache
     ‘.pyc’ files to (and read them from) a parallel directory tree
     rooted at this directory, rather than from ‘__pycache__’
     directories in the source code tree.  Any ‘__pycache__’ directories
     in the source code tree will be ignored and new ‘.pyc’ files
     written within the pycache prefix.  Thus if you use *note
     compileall: 20. as a pre-build step, you must ensure you run it
     with the same pycache prefix (if any) that you will use at runtime.

     A relative path is interpreted relative to the current working
     directory.

     This value is initially set based on the value of the *note -X:
     176. ‘pycache_prefix=PATH’ command-line option or the *note
     PYTHONPYCACHEPREFIX: 9ae. environment variable (command-line takes
     precedence).  If neither are set, it is ‘None’.

     Added in version 3.8.

 -- Function: sys.excepthook (type, value, traceback)

     This function prints out a given traceback and exception to
     ‘sys.stderr’.

     When an exception other than *note SystemExit: d69. is raised and
     uncaught, the interpreter calls ‘sys.excepthook’ with three
     arguments, the exception class, exception instance, and a traceback
     object.  In an interactive session this happens just before control
     is returned to the prompt; in a Python program this happens just
     before the program exits.  The handling of such top-level
     exceptions can be customized by assigning another three-argument
     function to ‘sys.excepthook’.

     Raise an auditing event ‘sys.excepthook’ with arguments ‘hook’,
     ‘type’, ‘value’, ‘traceback’ when an uncaught exception occurs.  If
     no hook has been set, ‘hook’ may be ‘None’.  If any hook raises an
     exception derived from *note RuntimeError: 195. the call to the
     hook will be suppressed.  Otherwise, the audit hook exception will
     be reported as unraisable and ‘sys.excepthook’ will be called.

     See also
     ........

     The *note sys.unraisablehook(): 1f7. function handles unraisable
     exceptions and the *note threading.excepthook(): 851. function
     handles exception raised by *note threading.Thread.run(): a4a.

 -- Data: sys.__breakpointhook__
 -- Data: sys.__displayhook__
 -- Data: sys.__excepthook__
 -- Data: sys.__unraisablehook__

     These objects contain the original values of ‘breakpointhook’,
     ‘displayhook’, ‘excepthook’, and ‘unraisablehook’ at the start of
     the program.  They are saved so that ‘breakpointhook’,
     ‘displayhook’ and ‘excepthook’, ‘unraisablehook’ can be restored in
     case they happen to get replaced with broken or alternative
     objects.

     Added in version 3.7: __breakpointhook__

     Added in version 3.8: __unraisablehook__

 -- Function: sys.exception ()

     This function, when called while an exception handler is executing
     (such as an ‘except’ or ‘except*’ clause), returns the exception
     instance that was caught by this handler.  When exception handlers
     are nested within one another, only the exception handled by the
     innermost handler is accessible.

     If no exception handler is executing, this function returns ‘None’.

     Added in version 3.11.

 -- Function: sys.exc_info ()

     This function returns the old-style representation of the handled
     exception.  If an exception ‘e’ is currently handled (so *note
     exception(): 68e. would return ‘e’), ‘exc_info()’ returns the tuple
     ‘(type(e), e, e.__traceback__)’.  That is, a tuple containing the
     type of the exception (a subclass of *note BaseException: 5be.),
     the exception itself, and a *note traceback object: b0d. which
     typically encapsulates the call stack at the point where the
     exception last occurred.

     If no exception is being handled anywhere on the stack, this
     function return a tuple containing three ‘None’ values.

     Changed in version 3.11: The ‘type’ and ‘traceback’ fields are now
     derived from the ‘value’ (the exception instance), so when an
     exception is modified while it is being handled, the changes are
     reflected in the results of subsequent calls to ‘exc_info()’.

 -- Data: sys.exec_prefix

     A string giving the site-specific directory prefix where the
     platform-dependent Python files are installed; by default, this is
     also ‘'/usr/local'’.  This can be set at build time with the
     ‘--exec-prefix’ argument to the ‘configure’ script.  Specifically,
     all configuration files (e.g.  the ‘pyconfig.h’ header file) are
     installed in the directory ‘`exec_prefix'/lib/python`X.Y'/config’,
     and shared library modules are installed in
     ‘`exec_prefix'/lib/python`X.Y'/lib-dynload’, where 'X.Y' is the
     version number of Python, for example ‘3.2’.

          Note: If a *note virtual environment: 4579. is in effect, this
          value will be changed in ‘site.py’ to point to the virtual
          environment.  The value for the Python installation will still
          be available, via *note base_exec_prefix: 3f1.

 -- Data: sys.executable

     A string giving the absolute path of the executable binary for the
     Python interpreter, on systems where this makes sense.  If Python
     is unable to retrieve the real path to its executable, *note
     sys.executable: 3bb. will be an empty string or ‘None’.

 -- Function: sys.exit ([arg])

     Raise a *note SystemExit: d69. exception, signaling an intention to
     exit the interpreter.

     The optional argument 'arg' can be an integer giving the exit
     status (defaulting to zero), or another type of object.  If it is
     an integer, zero is considered “successful termination” and any
     nonzero value is considered “abnormal termination” by shells and
     the like.  Most systems require it to be in the range 0–127, and
     produce undefined results otherwise.  Some systems have a
     convention for assigning specific meanings to specific exit codes,
     but these are generally underdeveloped; Unix programs generally use
     2 for command line syntax errors and 1 for all other kinds of
     errors.  If another type of object is passed, ‘None’ is equivalent
     to passing zero, and any other object is printed to *note stderr:
     943. and results in an exit code of 1.  In particular,
     ‘sys.exit("some error message")’ is a quick way to exit a program
     when an error occurs.

     Since ‘exit()’ ultimately “only” raises an exception, it will only
     exit the process when called from the main thread, and the
     exception is not intercepted.  Cleanup actions specified by finally
     clauses of *note try: 6ec. statements are honored, and it is
     possible to intercept the exit attempt at an outer level.

     Changed in version 3.6: If an error occurs in the cleanup after the
     Python interpreter has caught *note SystemExit: d69. (such as an
     error flushing buffered data in the standard streams), the exit
     status is changed to 120.

 -- Data: sys.flags

     The *note named tuple: 651. 'flags' exposes the status of command
     line flags.  The attributes are read only.

      -- Attribute: flags.debug                             *note -d: 1eda.
                                                            
                                                            
      -- Attribute: flags.inspect                           *note -i: 152a.
                                                            
                                                            
      -- Attribute: flags.interactive                       *note -i: 152a.
                                                            
                                                            
      -- Attribute: flags.isolated                          *note -I: 968.
                                                            
                                                            
      -- Attribute: flags.optimize                          *note -O: de3. or *note -OO: de4.
                                                            
                                                            
      -- Attribute: flags.dont_write_bytecode               *note -B: 141b.
                                                            
                                                            
      -- Attribute: flags.no_user_site                      *note -s: 13db.
                                                            
                                                            
      -- Attribute: flags.no_site                           *note -S: 11ec.
                                                            
                                                            
      -- Attribute: flags.ignore_environment                *note -E: 967.
                                                            
                                                            
      -- Attribute: flags.verbose                           *note -v: 1473.
                                                            
                                                            
      -- Attribute: flags.bytes_warning                     *note -b: 5e6.
                                                            
                                                            
      -- Attribute: flags.quiet                             *note -q: 15c9.
                                                            
                                                            
      -- Attribute: flags.hash_randomization                *note -R: 1c29.
                                                            
                                                            
      -- Attribute: flags.dev_mode                          *note -X dev: 176.
                                                            (*note Python Development Mode: 1f8.)
                                                            
                                                            
      -- Attribute: flags.utf8_mode                         *note -X utf8: 176.
                                                            
                                                            
      -- Attribute: flags.safe_path                         *note -P: 5a7.
                                                            
                                                            
      -- Attribute: flags.int_max_str_digits                *note -X int_max_str_digits: 176.
                                                            (*note integer string conversion length limitation: 5f8.)
                                                            
                                                            
      -- Attribute: flags.warn_default_encoding             *note -X warn_default_encoding: 176.
                                                            

     Changed in version 3.2: Added ‘quiet’ attribute for the new *note
     -q: 15c9. flag.

     Added in version 3.2.3: The ‘hash_randomization’ attribute.

     Changed in version 3.3: Removed obsolete ‘division_warning’
     attribute.

     Changed in version 3.4: Added ‘isolated’ attribute for *note -I:
     968. ‘isolated’ flag.

     Changed in version 3.7: Added the ‘dev_mode’ attribute for the new
     *note Python Development Mode: 1f8. and the ‘utf8_mode’ attribute
     for the new *note -X: 176. ‘utf8’ flag.

     Changed in version 3.10: Added ‘warn_default_encoding’ attribute
     for *note -X: 176. ‘warn_default_encoding’ flag.

     Changed in version 3.11: Added the ‘safe_path’ attribute for *note
     -P: 5a7. option.

     Changed in version 3.11: Added the ‘int_max_str_digits’ attribute.

 -- Data: sys.float_info

     A *note named tuple: 651. holding information about the float type.
     It contains low level information about the precision and internal
     representation.  The values correspond to the various
     floating-point constants defined in the standard header file
     ‘float.h’ for the ‘C’ programming language; see section 5.2.4.2.2
     of the 1999 ISO/IEC C standard *note [C99]: 45ce, ‘Characteristics
     of floating types’, for details.  Attributes of the ‘float_info’
     named tuple

     attribute                             float.h macro                         explanation
                                                                                 
     ------------------------------------------------------------------------------------------------------------------
                                                                                 
      -- Attribute: float_info.epsilon     ‘DBL_EPSILON’                         difference between 1.0 and the
                                                                                 least value greater than 1.0 that
                                                                                 is representable as a float.
                                                                                 
                                                                                 See also *note math.ulp(): 91b.
                                                                                 
                                                                                 
      -- Attribute: float_info.dig         ‘DBL_DIG’                             The maximum number of decimal
                                                                                 digits that can be faithfully
                                                                                 represented in a float; see below.
                                                                                 
                                                                                 
      -- Attribute: float_info.mant_dig    ‘DBL_MANT_DIG’                        Float precision: the number of
                                                                                 base-‘radix’ digits in the
                                                                                 significand of a float.
                                                                                 
                                                                                 
      -- Attribute: float_info.max         ‘DBL_MAX’                             The maximum representable positive
                                                                                 finite float.
                                                                                 
                                                                                 
      -- Attribute: float_info.max_exp     ‘DBL_MAX_EXP’                         The maximum integer 'e' such that
                                                                                 ‘radix**(e-1)’ is a representable
                                                                                 finite float.
                                                                                 
                                                                                 
      -- Attribute:                        ‘DBL_MAX_10_EXP’                      The maximum integer 'e' such that
               float_info.max_10_exp                                             ‘10**e’ is in the range of
                                                                                 representable finite floats.
                                                                                 
                                                                                 
      -- Attribute: float_info.min         ‘DBL_MIN’                             The minimum representable positive
                                                                                 'normalized' float.
                                                                                 
                                                                                 Use *note math.ulp(0.0): 91b. to
                                                                                 get the smallest positive
                                                                                 'denormalized' representable float.
                                                                                 
                                                                                 
      -- Attribute: float_info.min_exp     ‘DBL_MIN_EXP’                         The minimum integer 'e' such that
                                                                                 ‘radix**(e-1)’ is a normalized
                                                                                 float.
                                                                                 
                                                                                 
      -- Attribute:                        ‘DBL_MIN_10_EXP’                      The minimum integer 'e' such that
               float_info.min_10_exp                                             ‘10**e’ is a normalized float.
                                                                                 
                                                                                 
      -- Attribute: float_info.radix       ‘FLT_RADIX’                           The radix of exponent
                                                                                 representation.
                                                                                 
                                                                                 
      -- Attribute: float_info.rounds      ‘FLT_ROUNDS’                          An integer representing the
                                                                                 rounding mode for floating-point
                                                                                 arithmetic.  This reflects the
                                                                                 value of the system ‘FLT_ROUNDS’
                                                                                 macro at interpreter startup time:
                                                                                 
                                                                                    * ‘-1’: indeterminable
                                                                                 
                                                                                    * ‘0’: toward zero
                                                                                 
                                                                                    * ‘1’: to nearest
                                                                                 
                                                                                    * ‘2’: toward positive infinity
                                                                                 
                                                                                    * ‘3’: toward negative infinity
                                                                                 
                                                                                 All other values for ‘FLT_ROUNDS’
                                                                                 characterize implementation-defined
                                                                                 rounding behavior.
                                                                                 

     The attribute *note sys.float_info.dig: 45d0. needs further
     explanation.  If ‘s’ is any string representing a decimal number
     with at most ‘sys.float_info.dig’ significant digits, then
     converting ‘s’ to a float and back again will recover a string
     representing the same decimal value:

          >>> import sys
          >>> sys.float_info.dig
          15
          >>> s = '3.14159265358979'    # decimal string with 15 significant digits
          >>> format(float(s), '.15g')  # convert to float and back -> same value
          '3.14159265358979'

     But for strings with more than *note sys.float_info.dig: 45d0.
     significant digits, this isn’t always true:

          >>> s = '9876543211234567'    # 16 significant digits is too many!
          >>> format(float(s), '.16g')  # conversion changes value
          '9876543211234568'

 -- Data: sys.float_repr_style

     A string indicating how the *note repr(): 803. function behaves for
     floats.  If the string has value ‘'short'’ then for a finite float
     ‘x’, ‘repr(x)’ aims to produce a short string with the property
     that ‘float(repr(x)) == x’.  This is the usual behaviour in Python
     3.1 and later.  Otherwise, ‘float_repr_style’ has value ‘'legacy'’
     and ‘repr(x)’ behaves in the same way as it did in versions of
     Python prior to 3.1.

     Added in version 3.1.

 -- Function: sys.getallocatedblocks ()

     Return the number of memory blocks currently allocated by the
     interpreter, regardless of their size.  This function is mainly
     useful for tracking and debugging memory leaks.  Because of the
     interpreter’s internal caches, the result can vary from call to
     call; you may have to call *note _clear_internal_caches(): 1783.
     and *note gc.collect(): a47. to get more predictable results.

     If a Python build or implementation cannot reasonably compute this
     information, ‘getallocatedblocks()’ is allowed to return 0 instead.

     Added in version 3.4.

 -- Function: sys.getunicodeinternedsize ()

     Return the number of unicode objects that have been interned.

     Added in version 3.12.

 -- Function: sys.getandroidapilevel ()

     Return the build-time API level of Android as an integer.  This
     represents the minimum version of Android this build of Python can
     run on.  For runtime version information, see *note
     platform.android_ver(): 175a.

     *note Availability: 1ef7.: Android.

     Added in version 3.7.

 -- Function: sys.getdefaultencoding ()

     Return ‘'utf-8'’.  This is the name of the default string encoding,
     used in methods like *note str.encode(): 8de.

 -- Function: sys.getdlopenflags ()

     Return the current value of the flags that are used for ‘dlopen()’
     calls.  Symbolic names for the flag values can be found in the
     *note os: a1. module (‘RTLD_XXX’ constants, e.g.  *note
     os.RTLD_LAZY: 115c.).

     *note Availability: 1ef7.: Unix.

 -- Function: sys.getfilesystemencoding ()

     Get the *note filesystem encoding: 53e.: the encoding used with the
     filesystem error handler to convert between Unicode filenames and
     bytes filenames.  The filesystem error handler is returned from
     *note getfilesystemencodeerrors(): d0d.

     For best compatibility, str should be used for filenames in all
     cases, although representing filenames as bytes is also supported.
     Functions accepting or returning filenames should support either
     str or bytes and internally convert to the system’s preferred
     representation.

     *note os.fsencode(): c76. and *note os.fsdecode(): c75. should be
     used to ensure that the correct encoding and errors mode are used.

     The *note filesystem encoding and error handler: 53e. are
     configured at Python startup by the *note PyConfig_Read(): 793.
     function: see *note filesystem_encoding: 3eb. and *note
     filesystem_errors: 3ec. members of *note PyConfig: 3a9.

     Changed in version 3.2: ‘getfilesystemencoding()’ result cannot be
     ‘None’ anymore.

     Changed in version 3.6: Windows is no longer guaranteed to return
     ‘'mbcs'’.  See PEP 529(3) and *note
     _enablelegacywindowsfsencoding(): 2ae. for more information.

     Changed in version 3.7: Return ‘'utf-8'’ if the *note Python UTF-8
     Mode: 659. is enabled.

 -- Function: sys.getfilesystemencodeerrors ()

     Get the *note filesystem error handler: 53e.: the error handler
     used with the filesystem encoding to convert between Unicode
     filenames and bytes filenames.  The filesystem encoding is returned
     from *note getfilesystemencoding(): c7a.

     *note os.fsencode(): c76. and *note os.fsdecode(): c75. should be
     used to ensure that the correct encoding and errors mode are used.

     The *note filesystem encoding and error handler: 53e. are
     configured at Python startup by the *note PyConfig_Read(): 793.
     function: see *note filesystem_encoding: 3eb. and *note
     filesystem_errors: 3ec. members of *note PyConfig: 3a9.

     Added in version 3.6.

 -- Function: sys.get_int_max_str_digits ()

     Returns the current value for the *note integer string conversion
     length limitation: 5f8.  See also *note set_int_max_str_digits():
     18e0.

     Added in version 3.11.

 -- Function: sys.getrefcount (object)

     Return the reference count of the 'object'.  The count returned is
     generally one higher than you might expect, because it includes the
     (temporary) reference as an argument to ‘getrefcount()’.

     Note that the returned value may not actually reflect how many
     references to the object are actually held.  For example, some
     objects are *note immortal: 45dd. and have a very high refcount
     that does not reflect the actual number of references.
     Consequently, do not rely on the returned value to be accurate,
     other than a value of 0 or 1.

     Changed in version 3.12: Immortal objects have very large refcounts
     that do not match the actual number of references to the object.

 -- Function: sys.getrecursionlimit ()

     Return the current value of the recursion limit, the maximum depth
     of the Python interpreter stack.  This limit prevents infinite
     recursion from causing an overflow of the C stack and crashing
     Python.  It can be set by *note setrecursionlimit(): 4c6.

 -- Function: sys.getsizeof (object[, default])

     Return the size of an object in bytes.  The object can be any type
     of object.  All built-in objects will return correct results, but
     this does not have to hold true for third-party extensions as it is
     implementation specific.

     Only the memory consumption directly attributed to the object is
     accounted for, not the memory consumption of objects it refers to.

     If given, 'default' will be returned if the object does not provide
     means to retrieve the size.  Otherwise a *note TypeError: 2c3. will
     be raised.

     ‘getsizeof()’ calls the object’s ‘__sizeof__’ method and adds an
     additional garbage collector overhead if the object is managed by
     the garbage collector.

     See recursive sizeof recipe(4) for an example of using
     ‘getsizeof()’ recursively to find the size of containers and all
     their contents.

 -- Function: sys.getswitchinterval ()

     Return the interpreter’s “thread switch interval” in seconds; see
     *note setswitchinterval(): 954.

     Added in version 3.2.

 -- Function: sys._getframe ([depth])

     Return a frame object from the call stack.  If optional integer
     'depth' is given, return the frame object that many calls below the
     top of the stack.  If that is deeper than the call stack, *note
     ValueError: 202. is raised.  The default for 'depth' is zero,
     returning the frame at the top of the call stack.

     Raises an *note auditing event: 1a15. ‘sys._getframe’ with argument
     ‘frame’.

     'CPython implementation detail:' This function should be used for
     internal and specialized purposes only.  It is not guaranteed to
     exist in all implementations of Python.

 -- Function: sys._getframemodulename ([depth])

     Return the name of a module from the call stack.  If optional
     integer 'depth' is given, return the module that many calls below
     the top of the stack.  If that is deeper than the call stack, or if
     the module is unidentifiable, ‘None’ is returned.  The default for
     'depth' is zero, returning the module at the top of the call stack.

     Raises an *note auditing event: 1a15. ‘sys._getframemodulename’
     with argument ‘depth’.

     'CPython implementation detail:' This function should be used for
     internal and specialized purposes only.  It is not guaranteed to
     exist in all implementations of Python.

     Added in version 3.12.

 -- Function: sys.getobjects (limit[, type])

     This function only exists if CPython was built using the
     specialized configure option *note -with-trace-refs: 398.  It is
     intended only for debugging garbage-collection issues.

     Return a list of up to 'limit' dynamically allocated Python
     objects.  If 'type' is given, only objects of that exact type (not
     subtypes) are included.

     Objects from the list are not safe to use.  Specifically, the
     result will include objects from all interpreters that share their
     object allocator state (that is, ones created with *note
     PyInterpreterConfig.use_main_obmalloc: 45de. set to 1 or using
     *note Py_NewInterpreter(): 18d4, and the *note main interpreter:
     58a.).  Mixing objects from different interpreters may lead to
     crashes or other unexpected behavior.

     'CPython implementation detail:' This function should be used for
     specialized purposes only.  It is not guaranteed to exist in all
     implementations of Python.

     Changed in version 3.13.1: The result may include objects from
     other interpreters.

 -- Function: sys.getprofile ()

     Get the profiler function as set by *note setprofile(): 154d.

 -- Function: sys.gettrace ()

     Get the trace function as set by *note settrace(): 154e.

     'CPython implementation detail:' The ‘gettrace()’ function is
     intended only for implementing debuggers, profilers, coverage tools
     and the like.  Its behavior is part of the implementation platform,
     rather than part of the language definition, and thus may not be
     available in all Python implementations.

 -- Function: sys.getwindowsversion ()

     Return a named tuple describing the Windows version currently
     running.  The named elements are 'major', 'minor', 'build',
     'platform', 'service_pack', 'service_pack_minor',
     'service_pack_major', 'suite_mask', 'product_type' and
     'platform_version'.  'service_pack' contains a string,
     'platform_version' a 3-tuple and all other values are integers.
     The components can also be accessed by name, so
     ‘sys.getwindowsversion()[0]’ is equivalent to
     ‘sys.getwindowsversion().major’.  For compatibility with prior
     versions, only the first 5 elements are retrievable by indexing.

     'platform' will be ‘2’ (VER_PLATFORM_WIN32_NT).

     'product_type' may be one of the following values:

     Constant                                    Meaning
                                                 
     ----------------------------------------------------------------------------------
                                                 
     ‘1’ (VER_NT_WORKSTATION)                    The system is a workstation.
                                                 
                                                 
     ‘2’ (VER_NT_DOMAIN_CONTROLLER)              The system is a domain controller.
                                                 
                                                 
     ‘3’ (VER_NT_SERVER)                         The system is a server, but not a
                                                 domain controller.
                                                 

     This function wraps the Win32 ‘GetVersionEx()’ function; see the
     Microsoft documentation on ‘OSVERSIONINFOEX()’ for more information
     about these fields.

     'platform_version' returns the major version, minor version and
     build number of the current operating system, rather than the
     version that is being emulated for the process.  It is intended for
     use in logging rather than for feature detection.

          Note: 'platform_version' derives the version from kernel32.dll
          which can be of a different version than the OS version.
          Please use *note platform: aa. module for achieving accurate
          OS version.

     *note Availability: 1ef7.: Windows.

     Changed in version 3.2: Changed to a named tuple and added
     'service_pack_minor', 'service_pack_major', 'suite_mask', and
     'product_type'.

     Changed in version 3.6: Added 'platform_version'

 -- Function: sys.get_asyncgen_hooks ()

     Returns an 'asyncgen_hooks' object, which is similar to a *note
     namedtuple: 1ca. of the form ‘(firstiter, finalizer)’, where
     'firstiter' and 'finalizer' are expected to be either ‘None’ or
     functions which take an *note asynchronous generator iterator:
     361f. as an argument, and are used to schedule finalization of an
     asynchronous generator by an event loop.

     Added in version 3.6: See PEP 525(5) for more details.

          Note: This function has been added on a provisional basis (see
          PEP 411(6) for details.)

 -- Function: sys.get_coroutine_origin_tracking_depth ()

     Get the current coroutine origin tracking depth, as set by *note
     set_coroutine_origin_tracking_depth(): baa.

     Added in version 3.7.

          Note: This function has been added on a provisional basis (see
          PEP 411(7) for details.)  Use it only for debugging purposes.

 -- Data: sys.hash_info

     A *note named tuple: 651. giving parameters of the numeric hash
     implementation.  For more details about hashing of numeric types,
     see *note Hashing of numeric types: 2358.

      -- Attribute: hash_info.width

          The width in bits used for hash values

      -- Attribute: hash_info.modulus

          The prime modulus P used for numeric hash scheme

      -- Attribute: hash_info.inf

          The hash value returned for a positive infinity

      -- Attribute: hash_info.nan

          (This attribute is no longer used)

      -- Attribute: hash_info.imag

          The multiplier used for the imaginary part of a complex number

      -- Attribute: hash_info.algorithm

          The name of the algorithm for hashing of str, bytes, and
          memoryview

      -- Attribute: hash_info.hash_bits

          The internal output size of the hash algorithm

      -- Attribute: hash_info.seed_bits

          The size of the seed key of the hash algorithm

      -- Attribute: hash_info.cutoff

          Cutoff for small string DJBX33A optimization in range ‘[1,
          cutoff)’.

     Added in version 3.2.

     Changed in version 3.4: Added 'algorithm', 'hash_bits',
     'seed_bits', and 'cutoff'.

 -- Data: sys.hexversion

     The version number encoded as a single integer.  This is guaranteed
     to increase with each version, including proper support for
     non-production releases.  For example, to test that the Python
     interpreter is at least version 1.5.2, use:

          if sys.hexversion >= 0x010502F0:
              # use some advanced feature
              ...
          else:
              # use an alternative implementation or warn the user
              ...

     This is called ‘hexversion’ since it only really looks meaningful
     when viewed as the result of passing it to the built-in *note
     hex(): 1317. function.  The *note named tuple: 651. *note
     sys.version_info: 6a3. may be used for a more human-friendly
     encoding of the same information.

     More details of ‘hexversion’ can be found at *note API and ABI
     Versioning: 45e8.

 -- Data: sys.implementation

     An object containing information about the implementation of the
     currently running Python interpreter.  The following attributes are
     required to exist in all Python implementations.

     'name' is the implementation’s identifier, e.g.  ‘'cpython'’.  The
     actual string is defined by the Python implementation, but it is
     guaranteed to be lower case.

     'version' is a named tuple, in the same format as *note
     sys.version_info: 6a3.  It represents the version of the Python
     'implementation'.  This has a distinct meaning from the specific
     version of the Python 'language' to which the currently running
     interpreter conforms, which ‘sys.version_info’ represents.  For
     example, for PyPy 1.8 ‘sys.implementation.version’ might be
     ‘sys.version_info(1, 8, 0, 'final', 0)’, whereas ‘sys.version_info’
     would be ‘sys.version_info(2, 7, 2, 'final', 0)’.  For CPython they
     are the same value, since it is the reference implementation.

     'hexversion' is the implementation version in hexadecimal format,
     like *note sys.hexversion: 45e7.

     'cache_tag' is the tag used by the import machinery in the
     filenames of cached modules.  By convention, it would be a
     composite of the implementation’s name and version, like
     ‘'cpython-33'’.  However, a Python implementation may use some
     other value if appropriate.  If ‘cache_tag’ is set to ‘None’, it
     indicates that module caching should be disabled.

     *note sys.implementation: 51a. may contain additional attributes
     specific to the Python implementation.  These non-standard
     attributes must start with an underscore, and are not described
     here.  Regardless of its contents, ‘sys.implementation’ will not
     change during a run of the interpreter, nor between implementation
     versions.  (It may change between Python language versions,
     however.)  See PEP 421(8) for more information.

     Added in version 3.3.

          Note: The addition of new required attributes must go through
          the normal PEP process.  See PEP 421(9) for more information.

 -- Data: sys.int_info

     A *note named tuple: 651. that holds information about Python’s
     internal representation of integers.  The attributes are read only.

      -- Attribute: int_info.bits_per_digit

          The number of bits held in each digit.  Python integers are
          stored internally in base ‘2**int_info.bits_per_digit’.

      -- Attribute: int_info.sizeof_digit

          The size in bytes of the C type used to represent a digit.

      -- Attribute: int_info.default_max_str_digits

          The default value for *note sys.get_int_max_str_digits():
          1634. when it is not otherwise explicitly configured.

      -- Attribute: int_info.str_digits_check_threshold

          The minimum non-zero value for *note
          sys.set_int_max_str_digits(): 18e0, *note
          PYTHONINTMAXSTRDIGITS: 18dd, or *note -X int_max_str_digits:
          176.

     Added in version 3.1.

     Changed in version 3.11: Added *note default_max_str_digits: 2434.
     and *note str_digits_check_threshold: 45eb.

 -- Data: sys.__interactivehook__

     When this attribute exists, its value is automatically called (with
     no arguments) when the interpreter is launched in *note interactive
     mode: 1001.  This is done after the *note PYTHONSTARTUP: 1003. file
     is read, so that you can set this hook there.  The *note site: c7.
     module *note sets this: 1004.

     Raises an *note auditing event: 1a15. ‘cpython.run_interactivehook’
     with the hook object as the argument when the hook is called on
     startup.

     Added in version 3.4.

 -- Function: sys.intern (string)

     Enter 'string' in the table of “interned” strings and return the
     interned string – which is 'string' itself or a copy.  Interning
     strings is useful to gain a little performance on dictionary lookup
     – if the keys in a dictionary are interned, and the lookup key is
     interned, the key comparisons (after hashing) can be done by a
     pointer compare instead of a string compare.  Normally, the names
     used in Python programs are automatically interned, and the
     dictionaries used to hold module, class or instance attributes have
     interned keys.

     Interned strings are not *note immortal: 45dd.; you must keep a
     reference to the return value of ‘intern()’ around to benefit from
     it.

 -- Function: sys._is_gil_enabled ()

     Return *note True: c2d. if the *note GIL: 159. is enabled and *note
     False: b4f. if it is disabled.

     Added in version 3.13.

     'CPython implementation detail:' It is not guaranteed to exist in
     all implementations of Python.

 -- Function: sys.is_finalizing ()

     Return *note True: c2d. if the main Python interpreter is *note
     shutting down: 14e.  Return *note False: b4f. otherwise.

     See also the *note PythonFinalizationError: 14d. exception.

     Added in version 3.5.

 -- Data: sys.last_exc

     This variable is not always defined; it is set to the exception
     instance when an exception is not handled and the interpreter
     prints an error message and a stack traceback.  Its intended use is
     to allow an interactive user to import a debugger module and engage
     in post-mortem debugging without having to re-execute the command
     that caused the error.  (Typical use is ‘import pdb; pdb.pm()’ to
     enter the post-mortem debugger; see *note pdb: a5. module for more
     information.)

     Added in version 3.12.

 -- Function: sys._is_interned (string)

     Return *note True: c2d. if the given string is “interned”, *note
     False: b4f. otherwise.

     Added in version 3.13.

     'CPython implementation detail:' It is not guaranteed to exist in
     all implementations of Python.

 -- Data: sys.last_type
 -- Data: sys.last_value
 -- Data: sys.last_traceback

     These three variables are deprecated; use *note sys.last_exc: 4c1.
     instead.  They hold the legacy representation of ‘sys.last_exc’, as
     returned from *note exc_info(): 68d. above.

 -- Data: sys.maxsize

     An integer giving the maximum value a variable of type *note
     Py_ssize_t: a6e. can take.  It’s usually ‘2**31 - 1’ on a 32-bit
     platform and ‘2**63 - 1’ on a 64-bit platform.

 -- Data: sys.maxunicode

     An integer giving the value of the largest Unicode code point, i.e.
     ‘1114111’ (‘0x10FFFF’ in hexadecimal).

     Changed in version 3.3: Before PEP 393(10), ‘sys.maxunicode’ used
     to be either ‘0xFFFF’ or ‘0x10FFFF’, depending on the configuration
     option that specified whether Unicode characters were stored as
     UCS-2 or UCS-4.

 -- Data: sys.meta_path

     A list of *note meta path finder: 10ae. objects that have their
     *note find_spec(): 86f. methods called to see if one of the objects
     can find the module to be imported.  By default, it holds entries
     that implement Python’s default import semantics.  The
     ‘find_spec()’ method is called with at least the absolute name of
     the module being imported.  If the module to be imported is
     contained in a package, then the parent package’s *note __path__:
     1e0c. attribute is passed in as a second argument.  The method
     returns a *note module spec: 20c5, or ‘None’ if the module cannot
     be found.

     See also
     ........

     *note importlib.abc.MetaPathFinder: 875.

          The abstract base class defining the interface of finder
          objects on ‘meta_path’.

     *note importlib.machinery.ModuleSpec: 200d.

          The concrete class which *note find_spec(): 86f. should return
          instances of.

     Changed in version 3.4: *note Module specs: 20c5. were introduced
     in Python 3.4, by PEP 451(11).

     Changed in version 3.12: Removed the fallback that looked for a
     ‘find_module()’ method if a ‘meta_path’ entry didn’t have a *note
     find_spec(): 86f. method.

 -- Data: sys.modules

     This is a dictionary that maps module names to modules which have
     already been loaded.  This can be manipulated to force reloading of
     modules and other tricks.  However, replacing the dictionary will
     not necessarily work as expected and deleting essential items from
     the dictionary may cause Python to fail.  If you want to iterate
     over this global dictionary always use ‘sys.modules.copy()’ or
     ‘tuple(sys.modules)’ to avoid exceptions as its size may change
     during iteration as a side effect of code or activity in other
     threads.

 -- Data: sys.orig_argv

     The list of the original command line arguments passed to the
     Python executable.

     The elements of *note sys.orig_argv: 846. are the arguments to the
     Python interpreter, while the elements of *note sys.argv: 12ab. are
     the arguments to the user’s program.  Arguments consumed by the
     interpreter itself will be present in ‘sys.orig_argv’ and missing
     from ‘sys.argv’.

     Added in version 3.10.

 -- Data: sys.path

     A list of strings that specifies the search path for modules.
     Initialized from the environment variable *note PYTHONPATH: 1058,
     plus an installation-dependent default.

     By default, as initialized upon program startup, a potentially
     unsafe path is prepended to *note sys.path: 3b7. ('before' the
     entries inserted as a result of *note PYTHONPATH: 1058.):

        * ‘python -m module’ command line: prepend the current working
          directory.

        * ‘python script.py’ command line: prepend the script’s
          directory.  If it’s a symbolic link, resolve symbolic links.

        * ‘python -c code’ and ‘python’ (REPL) command lines: prepend an
          empty string, which means the current working directory.

     To not prepend this potentially unsafe path, use the *note -P: 5a7.
     command line option or the *note PYTHONSAFEPATH: 5a8. environment
     variable.

     A program is free to modify this list for its own purposes.  Only
     strings should be added to *note sys.path: 3b7.; all other data
     types are ignored during import.

     See also
     ........

        * Module *note site: c7. This describes how to use .pth files to
          extend *note sys.path: 3b7.

 -- Data: sys.path_hooks

     A list of callables that take a path argument to try to create a
     *note finder: 20cd. for the path.  If a finder can be created, it
     is to be returned by the callable, else raise *note ImportError:
     41c.

     Originally specified in PEP 302(12).

 -- Data: sys.path_importer_cache

     A dictionary acting as a cache for *note finder: 20cd. objects.
     The keys are paths that have been passed to *note sys.path_hooks:
     105f. and the values are the finders that are found.  If a path is
     a valid file system path but no finder is found on ‘sys.path_hooks’
     then ‘None’ is stored.

     Originally specified in PEP 302(13).

 -- Data: sys.platform

     A string containing a platform identifier.  Known values are:

     System               ‘platform’ value
                          
     -----------------------------------------------------
                          
     AIX                  ‘'aix'’
                          
                          
     Android              ‘'android'’
                          
                          
     Emscripten           ‘'emscripten'’
                          
                          
     iOS                  ‘'ios'’
                          
                          
     Linux                ‘'linux'’
                          
                          
     macOS                ‘'darwin'’
                          
                          
     Windows              ‘'win32'’
                          
                          
     Windows/Cygwin       ‘'cygwin'’
                          
                          
     WASI                 ‘'wasi'’
                          

     On Unix systems not listed in the table, the value is the
     lowercased OS name as returned by ‘uname -s’, with the first part
     of the version as returned by ‘uname -r’ appended, e.g.  ‘'sunos5'’
     or ‘'freebsd8'’, 'at the time when Python was built'.  Unless you
     want to test for a specific system version, it is therefore
     recommended to use the following idiom:

          if sys.platform.startswith('freebsd'):
              # FreeBSD-specific code here...

     Changed in version 3.3: On Linux, *note sys.platform: a9c. doesn’t
     contain the major version anymore.  It is always ‘'linux'’, instead
     of ‘'linux2'’ or ‘'linux3'’.

     Changed in version 3.8: On AIX, *note sys.platform: a9c. doesn’t
     contain the major version anymore.  It is always ‘'aix'’, instead
     of ‘'aix5'’ or ‘'aix7'’.

     Changed in version 3.13: On Android, *note sys.platform: a9c. now
     returns ‘'android'’ rather than ‘'linux'’.

     See also
     ........

     *note os.name: 2d00. has a coarser granularity.  *note os.uname():
     115a. gives system-dependent version information.

     The *note platform: aa. module provides detailed checks for the
     system’s identity.

 -- Data: sys.platlibdir

     Name of the platform-specific library directory.  It is used to
     build the path of standard library and the paths of installed
     extension modules.

     It is equal to ‘"lib"’ on most platforms.  On Fedora and SuSE, it
     is equal to ‘"lib64"’ on 64-bit platforms which gives the following
     ‘sys.path’ paths (where ‘X.Y’ is the Python ‘major.minor’ version):

        * ‘/usr/lib64/pythonX.Y/’: Standard library (like ‘os.py’ of the
          *note os: a1. module)

        * ‘/usr/lib64/pythonX.Y/lib-dynload/’: C extension modules of
          the standard library (like the *note errno: 57. module, the
          exact filename is platform specific)

        * ‘/usr/lib/pythonX.Y/site-packages/’ (always use ‘lib’, not
          *note sys.platlibdir: 942.): Third-party modules

        * ‘/usr/lib64/pythonX.Y/site-packages/’: C extension modules of
          third-party packages

     Added in version 3.9.

 -- Data: sys.prefix

     A string giving the site-specific directory prefix where the
     platform independent Python files are installed; on Unix, the
     default is ‘/usr/local’.  This can be set at build time with the
     *note -prefix: 1f06. argument to the ‘configure’ script.  See *note
     Installation paths: 692. for derived paths.

          Note: If a *note virtual environment: 4579. is in effect, this
          value will be changed in ‘site.py’ to point to the virtual
          environment.  The value for the Python installation will still
          be available, via *note base_prefix: 3f2.

 -- Data: sys.ps1
 -- Data: sys.ps2

     Strings specifying the primary and secondary prompt of the
     interpreter.  These are only defined if the interpreter is in
     interactive mode.  Their initial values in this case are ‘'>>> '’
     and ‘'... '’.  If a non-string object is assigned to either
     variable, its *note str(): 44f. is re-evaluated each time the
     interpreter prepares to read a new interactive command; this can be
     used to implement a dynamic prompt.

 -- Function: sys.setdlopenflags (n)

     Set the flags used by the interpreter for ‘dlopen()’ calls, such as
     when the interpreter loads extension modules.  Among other things,
     this will enable a lazy resolving of symbols when importing a
     module, if called as ‘sys.setdlopenflags(0)’.  To share symbols
     across extension modules, call as
     ‘sys.setdlopenflags(os.RTLD_GLOBAL)’.  Symbolic names for the flag
     values can be found in the *note os: a1. module (‘RTLD_XXX’
     constants, e.g.  *note os.RTLD_LAZY: 115c.).

     *note Availability: 1ef7.: Unix.

 -- Function: sys.set_int_max_str_digits (maxdigits)

     Set the *note integer string conversion length limitation: 5f8.
     used by this interpreter.  See also *note get_int_max_str_digits():
     1634.

     Added in version 3.11.

 -- Function: sys.setprofile (profilefunc)

     Set the system’s profile function, which allows you to implement a
     Python source code profiler in Python.  See chapter *note The
     Python Profilers: 44bd. for more information on the Python
     profiler.  The system’s profile function is called similarly to the
     system’s trace function (see *note settrace(): 154e.), but it is
     called with different events, for example it isn’t called for each
     executed line of code (only on call and return, but the return
     event is reported even when an exception has been set).  The
     function is thread-specific, but there is no way for the profiler
     to know about context switches between threads, so it does not make
     sense to use this in the presence of multiple threads.  Also, its
     return value is not used, so it can simply return ‘None’.  Error in
     the profile function will cause itself unset.

          Note: The same tracing mechanism is used for ‘setprofile()’ as
          *note settrace(): 154e.  To trace calls with ‘setprofile()’
          inside a tracing function (e.g.  in a debugger breakpoint),
          see *note call_tracing(): 1968.

     Profile functions should have three arguments: 'frame', 'event',
     and 'arg'.  'frame' is the current stack frame.  'event' is a
     string: ‘'call'’, ‘'return'’, ‘'c_call'’, ‘'c_return'’, or
     ‘'c_exception'’.  'arg' depends on the event type.

     The events have the following meaning:

     ‘'call'’

          A function is called (or some other code block entered).  The
          profile function is called; 'arg' is ‘None’.

     ‘'return'’

          A function (or other code block) is about to return.  The
          profile function is called; 'arg' is the value that will be
          returned, or ‘None’ if the event is caused by an exception
          being raised.

     ‘'c_call'’

          A C function is about to be called.  This may be an extension
          function or a built-in.  'arg' is the C function object.

     ‘'c_return'’

          A C function has returned.  'arg' is the C function object.

     ‘'c_exception'’

          A C function has raised an exception.  'arg' is the C function
          object.

     Raises an *note auditing event: 1a15. ‘sys.setprofile’ with no
     arguments.

 -- Function: sys.setrecursionlimit (limit)

     Set the maximum depth of the Python interpreter stack to 'limit'.
     This limit prevents infinite recursion from causing an overflow of
     the C stack and crashing Python.

     The highest possible limit is platform-dependent.  A user may need
     to set the limit higher when they have a program that requires deep
     recursion and a platform that supports a higher limit.  This should
     be done with care, because a too-high limit can lead to a crash.

     If the new limit is too low at the current recursion depth, a *note
     RecursionError: d96. exception is raised.

     Changed in version 3.5.1: A *note RecursionError: d96. exception is
     now raised if the new limit is too low at the current recursion
     depth.

 -- Function: sys.setswitchinterval (interval)

     Set the interpreter’s thread switch interval (in seconds).  This
     floating-point value determines the ideal duration of the
     “timeslices” allocated to concurrently running Python threads.
     Please note that the actual value can be higher, especially if
     long-running internal functions or methods are used.  Also, which
     thread becomes scheduled at the end of the interval is the
     operating system’s decision.  The interpreter doesn’t have its own
     scheduler.

     Added in version 3.2.

 -- Function: sys.settrace (tracefunc)

     Set the system’s trace function, which allows you to implement a
     Python source code debugger in Python.  The function is
     thread-specific; for a debugger to support multiple threads, it
     must register a trace function using ‘settrace()’ for each thread
     being debugged or use *note threading.settrace(): 84e.

     Trace functions should have three arguments: 'frame', 'event', and
     'arg'.  'frame' is the *note current stack frame: 6e3.  'event' is
     a string: ‘'call'’, ‘'line'’, ‘'return'’, ‘'exception'’ or
     ‘'opcode'’.  'arg' depends on the event type.

     The trace function is invoked (with 'event' set to ‘'call'’)
     whenever a new local scope is entered; it should return a reference
     to a local trace function to be used for the new scope, or ‘None’
     if the scope shouldn’t be traced.

     The local trace function should return a reference to itself, or to
     another function which would then be used as the local trace
     function for the scope.

     If there is any error occurred in the trace function, it will be
     unset, just like ‘settrace(None)’ is called.

          Note: Tracing is disabled while calling the trace function
          (e.g.  a function set by ‘settrace()’).  For recursive tracing
          see *note call_tracing(): 1968.

     The events have the following meaning:

     ‘'call'’

          A function is called (or some other code block entered).  The
          global trace function is called; 'arg' is ‘None’; the return
          value specifies the local trace function.

     ‘'line'’

          The interpreter is about to execute a new line of code or
          re-execute the condition of a loop.  The local trace function
          is called; 'arg' is ‘None’; the return value specifies the new
          local trace function.  See ‘Objects/lnotab_notes.txt’ for a
          detailed explanation of how this works.  Per-line events may
          be disabled for a frame by setting *note f_trace_lines: bfc.
          to *note False: b4f. on that *note frame: 6e3.

     ‘'return'’

          A function (or other code block) is about to return.  The
          local trace function is called; 'arg' is the value that will
          be returned, or ‘None’ if the event is caused by an exception
          being raised.  The trace function’s return value is ignored.

     ‘'exception'’

          An exception has occurred.  The local trace function is
          called; 'arg' is a tuple ‘(exception, value, traceback)’; the
          return value specifies the new local trace function.

     ‘'opcode'’

          The interpreter is about to execute a new opcode (see *note
          dis: 38. for opcode details).  The local trace function is
          called; 'arg' is ‘None’; the return value specifies the new
          local trace function.  Per-opcode events are not emitted by
          default: they must be explicitly requested by setting *note
          f_trace_opcodes: bfd. to *note True: c2d. on the *note frame:
          6e3.

     Note that as an exception is propagated down the chain of callers,
     an ‘'exception'’ event is generated at each level.

     For more fine-grained usage, it’s possible to set a trace function
     by assigning ‘frame.f_trace = tracefunc’ explicitly, rather than
     relying on it being set indirectly via the return value from an
     already installed trace function.  This is also required for
     activating the trace function on the current frame, which
     ‘settrace()’ doesn’t do.  Note that in order for this to work, a
     global tracing function must have been installed with ‘settrace()’
     in order to enable the runtime tracing machinery, but it doesn’t
     need to be the same tracing function (e.g.  it could be a low
     overhead tracing function that simply returns ‘None’ to disable
     itself immediately on each frame).

     For more information on code and frame objects, refer to *note The
     standard type hierarchy: 2094.

     Raises an *note auditing event: 1a15. ‘sys.settrace’ with no
     arguments.

     'CPython implementation detail:' The ‘settrace()’ function is
     intended only for implementing debuggers, profilers, coverage tools
     and the like.  Its behavior is part of the implementation platform,
     rather than part of the language definition, and thus may not be
     available in all Python implementations.

     Changed in version 3.7: ‘'opcode'’ event type added; *note
     f_trace_lines: bfc. and *note f_trace_opcodes: bfd. attributes
     added to frames

 -- Function: sys.set_asyncgen_hooks ([firstiter] [, finalizer])

     Accepts two optional keyword arguments which are callables that
     accept an *note asynchronous generator iterator: 361f. as an
     argument.  The 'firstiter' callable will be called when an
     asynchronous generator is iterated for the first time.  The
     'finalizer' will be called when an asynchronous generator is about
     to be garbage collected.

     Raises an *note auditing event: 1a15.
     ‘sys.set_asyncgen_hooks_firstiter’ with no arguments.

     Raises an *note auditing event: 1a15.
     ‘sys.set_asyncgen_hooks_finalizer’ with no arguments.

     Two auditing events are raised because the underlying API consists
     of two calls, each of which must raise its own event.

     Added in version 3.6: See PEP 525(14) for more details, and for a
     reference example of a 'finalizer' method see the implementation of
     ‘asyncio.Loop.shutdown_asyncgens’ in Lib/asyncio/base_events.py(15)

          Note: This function has been added on a provisional basis (see
          PEP 411(16) for details.)

 -- Function: sys.set_coroutine_origin_tracking_depth (depth)

     Allows enabling or disabling coroutine origin tracking.  When
     enabled, the ‘cr_origin’ attribute on coroutine objects will
     contain a tuple of (filename, line number, function name) tuples
     describing the traceback where the coroutine object was created,
     with the most recent call first.  When disabled, ‘cr_origin’ will
     be ‘None’.

     To enable, pass a 'depth' value greater than zero; this sets the
     number of frames whose information will be captured.  To disable,
     pass set 'depth' to zero.

     This setting is thread-specific.

     Added in version 3.7.

          Note: This function has been added on a provisional basis (see
          PEP 411(17) for details.)  Use it only for debugging purposes.

 -- Function: sys.activate_stack_trampoline (backend, /)

     Activate the stack profiler trampoline 'backend'.  The only
     supported backend is ‘"perf"’.

     *note Availability: 1ef7.: Linux.

     Added in version 3.12.

     See also
     ........

        * *note Python support for the Linux perf profiler: 18f.

        * ‘https://perf.wiki.kernel.org’

 -- Function: sys.deactivate_stack_trampoline ()

     Deactivate the current stack profiler trampoline backend.

     If no stack profiler is activated, this function has no effect.

     *note Availability: 1ef7.: Linux.

     Added in version 3.12.

 -- Function: sys.is_stack_trampoline_active ()

     Return ‘True’ if a stack profiler trampoline is active.

     *note Availability: 1ef7.: Linux.

     Added in version 3.12.

 -- Function: sys._enablelegacywindowsfsencoding ()

     Changes the *note filesystem encoding and error handler: 53e. to
     ‘mbcs’ and ‘replace’ respectively, for consistency with versions of
     Python prior to 3.6.

     This is equivalent to defining the *note
     PYTHONLEGACYWINDOWSFSENCODING: 2af. environment variable before
     launching Python.

     See also *note sys.getfilesystemencoding(): c7a. and *note
     sys.getfilesystemencodeerrors(): d0d.

     *note Availability: 1ef7.: Windows.

          Note: Changing the filesystem encoding after Python startup is
          risky because the old fsencoding or paths encoded by the old
          fsencoding may be cached somewhere.  Use *note
          PYTHONLEGACYWINDOWSFSENCODING: 2af. instead.

     Added in version 3.6: See PEP 529(18) for more details.

     Deprecated since version 3.13, will be removed in version 3.16: Use
     *note PYTHONLEGACYWINDOWSFSENCODING: 2af. instead.

 -- Data: sys.stdin
 -- Data: sys.stdout
 -- Data: sys.stderr

     *note File objects: 1208. used by the interpreter for standard
     input, output and errors:

        * ‘stdin’ is used for all interactive input (including calls to
          *note input(): 1320.);

        * ‘stdout’ is used for the output of *note print(): fae. and
          *note expression: 2135. statements and for the prompts of
          *note input(): 1320.;

        * The interpreter’s own prompts and its error messages go to
          ‘stderr’.

     These streams are regular *note text files: 1e25. like those
     returned by the *note open(): 51f. function.  Their parameters are
     chosen as follows:

        * The encoding and error handling are is initialized from *note
          PyConfig.stdio_encoding: 3a6. and *note PyConfig.stdio_errors:
          45ed.

          On Windows, UTF-8 is used for the console device.
          Non-character devices such as disk files and pipes use the
          system locale encoding (i.e.  the ANSI codepage).  Non-console
          character devices such as NUL (i.e.  where ‘isatty()’ returns
          ‘True’) use the value of the console input and output
          codepages at startup, respectively for stdin and
          stdout/stderr.  This defaults to the system *note locale
          encoding: 242. if the process is not initially attached to a
          console.

          The special behaviour of the console can be overridden by
          setting the environment variable PYTHONLEGACYWINDOWSSTDIO
          before starting Python.  In that case, the console codepages
          are used as for any other character device.

          Under all platforms, you can override the character encoding
          by setting the *note PYTHONIOENCODING: 1045. environment
          variable before starting Python or by using the new *note -X:
          176. ‘utf8’ command line option and *note PYTHONUTF8: aee.
          environment variable.  However, for the Windows console, this
          only applies when *note PYTHONLEGACYWINDOWSSTDIO: c7c. is also
          set.

        * When interactive, the ‘stdout’ stream is line-buffered.
          Otherwise, it is block-buffered like regular text files.  The
          ‘stderr’ stream is line-buffered in both cases.  You can make
          both streams unbuffered by passing the *note -u: 1b36.
          command-line option or setting the *note PYTHONUNBUFFERED:
          1b37. environment variable.

     Changed in version 3.9: Non-interactive ‘stderr’ is now
     line-buffered instead of fully buffered.

          Note: To write or read binary data from/to the standard
          streams, use the underlying binary *note buffer: 12ea. object.
          For example, to write bytes to ‘stdout’, use
          ‘sys.stdout.buffer.write(b'abc')’.

          However, if you are writing a library (and do not control in
          which context its code will be executed), be aware that the
          standard streams may be replaced with file-like objects like
          *note io.StringIO: f5e. which do not support the ‘buffer’
          attribute.

 -- Data: sys.__stdin__
 -- Data: sys.__stdout__
 -- Data: sys.__stderr__

     These objects contain the original values of ‘stdin’, ‘stderr’ and
     ‘stdout’ at the start of the program.  They are used during
     finalization, and could be useful to print to the actual standard
     stream no matter if the ‘sys.std*’ object has been redirected.

     It can also be used to restore the actual files to known working
     file objects in case they have been overwritten with a broken
     object.  However, the preferred way to do this is to explicitly
     save the previous stream before replacing it, and restore the saved
     object.

          Note: Under some conditions ‘stdin’, ‘stdout’ and ‘stderr’ as
          well as the original values ‘__stdin__’, ‘__stdout__’ and
          ‘__stderr__’ can be ‘None’.  It is usually the case for
          Windows GUI apps that aren’t connected to a console and Python
          apps started with ‘pythonw’.

 -- Data: sys.stdlib_module_names

     A frozenset of strings containing the names of standard library
     modules.

     It is the same on all platforms.  Modules which are not available
     on some platforms and modules disabled at Python build are also
     listed.  All module kinds are listed: pure Python, built-in, frozen
     and extension modules.  Test modules are excluded.

     For packages, only the main package is listed: sub-packages and
     sub-modules are not listed.  For example, the ‘email’ package is
     listed, but the ‘email.mime’ sub-package and the ‘email.message’
     sub-module are not listed.

     See also the *note sys.builtin_module_names: 1dfd. list.

     Added in version 3.10.

 -- Data: sys.thread_info

     A *note named tuple: 651. holding information about the thread
     implementation.

      -- Attribute: thread_info.name

          The name of the thread implementation:

             * ‘"nt"’: Windows threads

             * ‘"pthread"’: POSIX threads

             * ‘"pthread-stubs"’: stub POSIX threads (on WebAssembly
               platforms without threading support)

             * ‘"solaris"’: Solaris threads

      -- Attribute: thread_info.lock

          The name of the lock implementation:

             * ‘"semaphore"’: a lock uses a semaphore

             * ‘"mutex+cond"’: a lock uses a mutex and a condition
               variable

             * ‘None’ if this information is unknown

      -- Attribute: thread_info.version

          The name and version of the thread library.  It is a string,
          or ‘None’ if this information is unknown.

     Added in version 3.3.

 -- Data: sys.tracebacklimit

     When this variable is set to an integer value, it determines the
     maximum number of levels of traceback information printed when an
     unhandled exception occurs.  The default is ‘1000’.  When set to
     ‘0’ or less, all traceback information is suppressed and only the
     exception type and value are printed.

 -- Function: sys.unraisablehook (unraisable, /)

     Handle an unraisable exception.

     Called when an exception has occurred but there is no way for
     Python to handle it.  For example, when a destructor raises an
     exception or during garbage collection (*note gc.collect(): a47.).

     The 'unraisable' argument has the following attributes:

        * ‘exc_type’: Exception type.

        * ‘exc_value’: Exception value, can be ‘None’.

        * ‘exc_traceback’: Exception traceback, can be ‘None’.

        * ‘err_msg’: Error message, can be ‘None’.

        * ‘object’: Object causing the exception, can be ‘None’.

     The default hook formats ‘err_msg’ and ‘object’ as: ‘f'{err_msg}:
     {object!r}'’; use “Exception ignored in” error message if ‘err_msg’
     is ‘None’.

     *note sys.unraisablehook(): 1f7. can be overridden to control how
     unraisable exceptions are handled.

     See also
     ........

     *note excepthook(): 811. which handles uncaught exceptions.

          Warning: Storing ‘exc_value’ using a custom hook can create a
          reference cycle.  It should be cleared explicitly to break the
          reference cycle when the exception is no longer needed.

          Storing ‘object’ using a custom hook can resurrect it if it is
          set to an object which is being finalized.  Avoid storing
          ‘object’ after the custom hook completes to avoid resurrecting
          objects.

     Raise an auditing event ‘sys.unraisablehook’ with arguments 'hook',
     'unraisable' when an exception that cannot be handled occurs.  The
     'unraisable' object is the same as what will be passed to the hook.
     If no hook has been set, 'hook' may be ‘None’.

     Added in version 3.8.

 -- Data: sys.version

     A string containing the version number of the Python interpreter
     plus additional information on the build number and compiler used.
     This string is displayed when the interactive interpreter is
     started.  Do not extract version information out of it, rather, use
     *note version_info: 6a3. and the functions provided by the *note
     platform: aa. module.

 -- Data: sys.api_version

     The C API version for this interpreter.  Programmers may find this
     useful when debugging version conflicts between Python and
     extension modules.

 -- Data: sys.version_info

     A tuple containing the five components of the version number:
     'major', 'minor', 'micro', 'releaselevel', and 'serial'.  All
     values except 'releaselevel' are integers; the release level is
     ‘'alpha'’, ‘'beta'’, ‘'candidate'’, or ‘'final'’.  The
     ‘version_info’ value corresponding to the Python version 2.0 is
     ‘(2, 0, 0, 'final', 0)’.  The components can also be accessed by
     name, so ‘sys.version_info[0]’ is equivalent to
     ‘sys.version_info.major’ and so on.

     Changed in version 3.1: Added named component attributes.

 -- Data: sys.warnoptions

     This is an implementation detail of the warnings framework; do not
     modify this value.  Refer to the *note warnings: 112. module for
     more information on the warnings framework.

 -- Data: sys.winver

     The version number used to form registry keys on Windows platforms.
     This is stored as string resource 1000 in the Python DLL. The value
     is normally the major and minor versions of the running Python
     interpreter.  It is provided in the ‘sys’ module for informational
     purposes; modifying this value has no effect on the registry keys
     used by Python.

     *note Availability: 1ef7.: Windows.

 -- Data: sys.monitoring

     Namespace containing functions and constants for register callbacks
     and controlling monitoring events.  See *note sys.monitoring: da.
     for details.

 -- Data: sys._xoptions

     A dictionary of the various implementation-specific flags passed
     through the *note -X: 176. command-line option.  Option names are
     either mapped to their values, if given explicitly, or to *note
     True: c2d.  Example:

          $ ./python -Xa=b -Xc
          Python 3.2a3+ (py3k, Oct 16 2010, 20:14:50)
          [GCC 4.4.3] on linux2
          Type "help", "copyright", "credits" or "license" for more information.
          >>> import sys
          >>> sys._xoptions
          {'a': 'b', 'c': True}

     'CPython implementation detail:' This is a CPython-specific way of
     accessing options passed through *note -X: 176.  Other
     implementations may export them through other means, or not at all.

     Added in version 3.2.

Citations
.........

(C99) ISO/IEC 9899:1999.  “Programming languages – C.” A public draft of
this standard is available at
‘https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3149/

   (2) https://peps.python.org/pep-0578/

   (3) https://peps.python.org/pep-0529/

   (4) 
https://code.activestate.com/recipes/577504-compute-memory-footprint-of-an-object-and-its-cont/

   (5) https://peps.python.org/pep-0525/

   (6) https://peps.python.org/pep-0411/

   (7) https://peps.python.org/pep-0411/

   (8) https://peps.python.org/pep-0421/

   (9) https://peps.python.org/pep-0421/

   (10) https://peps.python.org/pep-0393/

   (11) https://peps.python.org/pep-0451/

   (12) https://peps.python.org/pep-0302/

   (13) https://peps.python.org/pep-0302/

   (14) https://peps.python.org/pep-0525/

   (15) 
https://github.com/python/cpython/tree/3.13/Lib/asyncio/base_events.py

   (16) https://peps.python.org/pep-0411/

   (17) https://peps.python.org/pep-0411/

   (18) https://peps.python.org/pep-0529/


File: python.info,  Node: sys monitoring — Execution event monitoring,  Next: sysconfig — Provide access to Python’s configuration information,  Prev: sys — System-specific parameters and functions,  Up: Python Runtime Services

5.29.2 ‘sys.monitoring’ — Execution event monitoring
----------------------------------------------------

Added in version 3.12.

__________________________________________________________________

     Note: ‘sys.monitoring’ is a namespace within the *note sys: d9.
     module, not an independent module, so there is no need to ‘import
     sys.monitoring’, simply ‘import sys’ and then use ‘sys.monitoring’.

This namespace provides access to the functions and constants necessary
to activate and control event monitoring.

As programs execute, events occur that might be of interest to tools
that monitor execution.  The ‘sys.monitoring’ namespace provides means
to receive callbacks when events of interest occur.

The monitoring API consists of three components:

   * *note Tool identifiers: 45f7.

   * *note Events: 45f8.

   * *note Callbacks: 45f9.

* Menu:

* Tool identifiers::
* Events::
* Turning events on and off::
* Registering callback functions::


File: python.info,  Node: Tool identifiers,  Next: Events,  Up: sys monitoring — Execution event monitoring

5.29.2.1 Tool identifiers
.........................

A tool identifier is an integer and the associated name.  Tool
identifiers are used to discourage tools from interfering with each
other and to allow multiple tools to operate at the same time.
Currently tools are completely independent and cannot be used to monitor
each other.  This restriction may be lifted in the future.

Before registering or activating events, a tool should choose an
identifier.  Identifiers are integers in the range 0 to 5 inclusive.

* Menu:

* Registering and using tools::


File: python.info,  Node: Registering and using tools,  Up: Tool identifiers

5.29.2.2 Registering and using tools
....................................

 -- Function: sys.monitoring.use_tool_id (tool_id: int, name: str, /) ->
          None

     Must be called before 'tool_id' can be used.  'tool_id' must be in
     the range 0 to 5 inclusive.  Raises a *note ValueError: 202. if
     'tool_id' is in use.

 -- Function: sys.monitoring.free_tool_id (tool_id: int, /) -> None

     Should be called once a tool no longer requires 'tool_id'.

     Note: *note free_tool_id(): 45fc. will not disable global or local
     events associated with 'tool_id', nor will it unregister any
     callback functions.  This function is only intended to be used to
     notify the VM that the particular 'tool_id' is no longer in use.

 -- Function: sys.monitoring.get_tool (tool_id: int, /) -> str | None

     Returns the name of the tool if 'tool_id' is in use, otherwise it
     returns ‘None’.  'tool_id' must be in the range 0 to 5 inclusive.

All IDs are treated the same by the VM with regard to events, but the
following IDs are pre-defined to make co-operation of tools easier:

     sys.monitoring.DEBUGGER_ID = 0
     sys.monitoring.COVERAGE_ID = 1
     sys.monitoring.PROFILER_ID = 2
     sys.monitoring.OPTIMIZER_ID = 5


File: python.info,  Node: Events,  Next: Turning events on and off,  Prev: Tool identifiers,  Up: sys monitoring — Execution event monitoring

5.29.2.3 Events
...............

The following events are supported:

 -- monitoring-event: sys.monitoring.events.BRANCH

     A conditional branch is taken (or not).

 -- monitoring-event: sys.monitoring.events.CALL

     A call in Python code (event occurs before the call).

 -- monitoring-event: sys.monitoring.events.C_RAISE

     An exception raised from any callable, except for Python functions
     (event occurs after the exit).

 -- monitoring-event: sys.monitoring.events.C_RETURN

     Return from any callable, except for Python functions (event occurs
     after the return).

 -- monitoring-event: sys.monitoring.events.EXCEPTION_HANDLED

     An exception is handled.

 -- monitoring-event: sys.monitoring.events.INSTRUCTION

     A VM instruction is about to be executed.

 -- monitoring-event: sys.monitoring.events.JUMP

     An unconditional jump in the control flow graph is made.

 -- monitoring-event: sys.monitoring.events.LINE

     An instruction is about to be executed that has a different line
     number from the preceding instruction.

 -- monitoring-event: sys.monitoring.events.PY_RESUME

     Resumption of a Python function (for generator and coroutine
     functions), except for ‘throw()’ calls.

 -- monitoring-event: sys.monitoring.events.PY_RETURN

     Return from a Python function (occurs immediately before the
     return, the callee’s frame will be on the stack).

 -- monitoring-event: sys.monitoring.events.PY_START

     Start of a Python function (occurs immediately after the call, the
     callee’s frame will be on the stack)

 -- monitoring-event: sys.monitoring.events.PY_THROW

     A Python function is resumed by a ‘throw()’ call.

 -- monitoring-event: sys.monitoring.events.PY_UNWIND

     Exit from a Python function during exception unwinding.

 -- monitoring-event: sys.monitoring.events.PY_YIELD

     Yield from a Python function (occurs immediately before the yield,
     the callee’s frame will be on the stack).

 -- monitoring-event: sys.monitoring.events.RAISE

     An exception is raised, except those that cause a *note
     STOP_ITERATION: 460b. event.

 -- monitoring-event: sys.monitoring.events.RERAISE

     An exception is re-raised, for example at the end of a *note
     finally: 9d5. block.

 -- monitoring-event: sys.monitoring.events.STOP_ITERATION

     An artificial *note StopIteration: c1b. is raised; see *note the
     STOP_ITERATION event: 460d.

More events may be added in the future.

These events are attributes of the ‘sys.monitoring.events’ namespace.
Each event is represented as a power-of-2 integer constant.  To define a
set of events, simply bitwise OR the individual events together.  For
example, to specify both *note PY_RETURN: 4606. and *note PY_START:
4607. events, use the expression ‘PY_RETURN | PY_START’.

 -- monitoring-event: sys.monitoring.events.NO_EVENTS

     An alias for ‘0’ so users can do explicit comparisons like:

          if get_events(DEBUGGER_ID) == NO_EVENTS:
              ...

Events are divided into three groups:

* Menu:

* Local events::
* Ancillary events::
* Other events::
* The STOP_ITERATION event::


File: python.info,  Node: Local events,  Next: Ancillary events,  Up: Events

5.29.2.4 Local events
.....................

Local events are associated with normal execution of the program and
happen at clearly defined locations.  All local events can be disabled.
The local events are:

   * *note PY_START: 4607.

   * *note PY_RESUME: 4605.

   * *note PY_RETURN: 4606.

   * *note PY_YIELD: 460a.

   * *note CALL: 1751.

   * *note LINE: 4604.

   * *note INSTRUCTION: 4602.

   * *note JUMP: 4603.

   * *note BRANCH: 45fe.

   * *note STOP_ITERATION: 460b.


File: python.info,  Node: Ancillary events,  Next: Other events,  Prev: Local events,  Up: Events

5.29.2.5 Ancillary events
.........................

Ancillary events can be monitored like other events, but are controlled
by another event:

   * *note C_RAISE: 45ff.

   * *note C_RETURN: 4600.

The *note C_RETURN: 4600. and *note C_RAISE: 45ff. events are controlled
by the *note CALL: 1751. event.  ‘C_RETURN’ and ‘C_RAISE’ events will
only be seen if the corresponding ‘CALL’ event is being monitored.


File: python.info,  Node: Other events,  Next: The STOP_ITERATION event,  Prev: Ancillary events,  Up: Events

5.29.2.6 Other events
.....................

Other events are not necessarily tied to a specific location in the
program and cannot be individually disabled via *note DISABLE: 4614.

The other events that can be monitored are:

   * *note PY_THROW: 4608.

   * *note PY_UNWIND: 4609.

   * *note RAISE: 16f8.

   * *note EXCEPTION_HANDLED: 4601.


File: python.info,  Node: The STOP_ITERATION event,  Prev: Other events,  Up: Events

5.29.2.7 The STOP_ITERATION event
.................................

PEP 380(1) specifies that a *note StopIteration: c1b. exception is
raised when returning a value from a generator or coroutine.  However,
this is a very inefficient way to return a value, so some Python
implementations, notably CPython 3.12+, do not raise an exception unless
it would be visible to other code.

To allow tools to monitor for real exceptions without slowing down
generators and coroutines, the *note STOP_ITERATION: 460b. event is
provided.  ‘STOP_ITERATION’ can be locally disabled, unlike *note RAISE:
16f8.

   ---------- Footnotes ----------

   (1) 
https://peps.python.org/pep-0380/#use-of-stopiteration-to-return-values


File: python.info,  Node: Turning events on and off,  Next: Registering callback functions,  Prev: Events,  Up: sys monitoring — Execution event monitoring

5.29.2.8 Turning events on and off
..................................

In order to monitor an event, it must be turned on and a corresponding
callback must be registered.  Events can be turned on or off by setting
the events either globally or for a particular code object.

* Menu:

* Setting events globally::
* Per code object events::
* Disabling events::


File: python.info,  Node: Setting events globally,  Next: Per code object events,  Up: Turning events on and off

5.29.2.9 Setting events globally
................................

Events can be controlled globally by modifying the set of events being
monitored.

 -- Function: sys.monitoring.get_events (tool_id: int, /) -> int

     Returns the ‘int’ representing all the active events.

 -- Function: sys.monitoring.set_events (tool_id: int, event_set: int,
          /) -> None

     Activates all events which are set in 'event_set'.  Raises a *note
     ValueError: 202. if 'tool_id' is not in use.

No events are active by default.


File: python.info,  Node: Per code object events,  Next: Disabling events,  Prev: Setting events globally,  Up: Turning events on and off

5.29.2.10 Per code object events
................................

Events can also be controlled on a per code object basis.  The functions
defined below which accept a *note types.CodeType: 2df. should be
prepared to accept a look-alike object from functions which are not
defined in Python (see *note Monitoring C API: 15c.).

 -- Function: sys.monitoring.get_local_events (tool_id: int, code:
          CodeType, /) -> int

     Returns all the *note local events: 4610. for 'code'

 -- Function: sys.monitoring.set_local_events (tool_id: int, code:
          CodeType, event_set: int, /) -> None

     Activates all the *note local events: 4610. for 'code' which are
     set in 'event_set'.  Raises a *note ValueError: 202. if 'tool_id'
     is not in use.

Local events add to global events, but do not mask them.  In other
words, all global events will trigger for a code object, regardless of
the local events.


File: python.info,  Node: Disabling events,  Prev: Per code object events,  Up: Turning events on and off

5.29.2.11 Disabling events
..........................

 -- Data: sys.monitoring.DISABLE

     A special value that can be returned from a callback function to
     disable events for the current code location.

*note Local events: 4610. can be disabled for a specific code location
by returning *note sys.monitoring.DISABLE: 4614. from a callback
function.  This does not change which events are set, or any other code
locations for the same event.

Disabling events for specific locations is very important for high
performance monitoring.  For example, a program can be run under a
debugger with no overhead if the debugger disables all monitoring except
for a few breakpoints.

If *note DISABLE: 4614. is returned by a callback for a *note global
event: 4612, *note ValueError: 202. will be raised by the interpreter in
a non-specific location (that is, no traceback will be provided).

 -- Function: sys.monitoring.restart_events () -> None

     Enable all the events that were disabled by *note
     sys.monitoring.DISABLE: 4614. for all tools.


File: python.info,  Node: Registering callback functions,  Prev: Turning events on and off,  Up: sys monitoring — Execution event monitoring

5.29.2.12 Registering callback functions
........................................

To register a callable for events call

 -- Function: sys.monitoring.register_callback (tool_id: int, event:
          int, func: Callable | None, /) -> Callable | None

     Registers the callable 'func' for the 'event' with the given
     'tool_id'

     If another callback was registered for the given 'tool_id' and
     'event', it is unregistered and returned.  Otherwise
     ‘register_callback()’ returns ‘None’.

     Raises an *note auditing event: 1a15.
     ‘sys.monitoring.register_callback’ with argument ‘func’.

Functions can be unregistered by calling
‘sys.monitoring.register_callback(tool_id, event, None)’.

Callback functions can be registered and unregistered at any time.

* Menu:

* Callback function arguments::


File: python.info,  Node: Callback function arguments,  Up: Registering callback functions

5.29.2.13 Callback function arguments
.....................................

 -- Data: sys.monitoring.MISSING

     A special value that is passed to a callback function to indicate
     that there are no arguments to the call.

When an active event occurs, the registered callback function is called.
Different events will provide the callback function with different
arguments, as follows:

   * *note PY_START: 4607. and *note PY_RESUME: 4605.:

          func(code: CodeType, instruction_offset: int) -> DISABLE | Any

   * *note PY_RETURN: 4606. and *note PY_YIELD: 460a.:

          func(code: CodeType, instruction_offset: int, retval: object) -> DISABLE | Any

   * *note CALL: 1751, *note C_RAISE: 45ff. and *note C_RETURN: 4600.:

          func(code: CodeType, instruction_offset: int, callable: object, arg0: object | MISSING) -> DISABLE | Any

     If there are no arguments, 'arg0' is set to *note
     sys.monitoring.MISSING: 4620.

   * *note RAISE: 16f8, *note RERAISE: 460c, *note EXCEPTION_HANDLED:
     4601, *note PY_UNWIND: 4609, *note PY_THROW: 4608. and *note
     STOP_ITERATION: 460b.:

          func(code: CodeType, instruction_offset: int, exception: BaseException) -> DISABLE | Any

   * *note LINE: 4604.:

          func(code: CodeType, line_number: int) -> DISABLE | Any

   * *note BRANCH: 45fe. and *note JUMP: 4603.:

          func(code: CodeType, instruction_offset: int, destination_offset: int) -> DISABLE | Any

     Note that the 'destination_offset' is where the code will next
     execute.  For an untaken branch this will be the offset of the
     instruction following the branch.

   * *note INSTRUCTION: 4602.:

          func(code: CodeType, instruction_offset: int) -> DISABLE | Any


File: python.info,  Node: sysconfig — Provide access to Python’s configuration information,  Next: builtins — Built-in objects,  Prev: sys monitoring — Execution event monitoring,  Up: Python Runtime Services

5.29.3 ‘sysconfig’ — Provide access to Python’s configuration information
-------------------------------------------------------------------------

Added in version 3.2.

'Source code:' Lib/sysconfig(1)

__________________________________________________________________

The ‘sysconfig’ module provides access to Python’s configuration
information like the list of installation paths and the configuration
variables relevant for the current platform.

* Menu:

* Configuration variables::
* Installation paths::
* User scheme::
* Home scheme::
* Prefix scheme::
* Installation path functions::
* Other functions: Other functions<3>.
* Command-line usage: Command-line usage<4>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/sysconfig


File: python.info,  Node: Configuration variables,  Next: Installation paths,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.1 Configuration variables
................................

A Python distribution contains a ‘Makefile’ and a ‘pyconfig.h’ header
file that are necessary to build both the Python binary itself and
third-party C extensions compiled using ‘setuptools’.

‘sysconfig’ puts all variables found in these files in a dictionary that
can be accessed using *note get_config_vars(): 1069. or *note
get_config_var(): 1068.

Notice that on Windows, it’s a much smaller set.

 -- Function: sysconfig.get_config_vars (*args)

     With no arguments, return a dictionary of all configuration
     variables relevant for the current platform.

     With arguments, return a list of values that result from looking up
     each argument in the configuration variable dictionary.

     For each argument, if the value is not found, return ‘None’.

 -- Function: sysconfig.get_config_var (name)

     Return the value of a single variable 'name'.  Equivalent to
     ‘get_config_vars().get(name)’.

     If 'name' is not found, return ‘None’.

Example of usage:

     >>> import sysconfig
     >>> sysconfig.get_config_var('Py_ENABLE_SHARED')
     0
     >>> sysconfig.get_config_var('LIBDIR')
     '/usr/local/lib'
     >>> sysconfig.get_config_vars('AR', 'CXX')
     ['ar', 'g++']


File: python.info,  Node: Installation paths,  Next: User scheme,  Prev: Configuration variables,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.2 Installation paths
...........................

Python uses an installation scheme that differs depending on the
platform and on the installation options.  These schemes are stored in
‘sysconfig’ under unique identifiers based on the value returned by
*note os.name: 2d00.  The schemes are used by package installers to
determine where to copy files to.

Python currently supports nine schemes:

   - 'posix_prefix': scheme for POSIX platforms like Linux or macOS.
     This is the default scheme used when Python or a component is
     installed.

   - 'posix_home': scheme for POSIX platforms, when the 'home' option is
     used.  This scheme defines paths located under a specific home
     prefix.

   - 'posix_user': scheme for POSIX platforms, when the 'user' option is
     used.  This scheme defines paths located under the user’s home
     directory (*note site.USER_BASE: 1366.).

   - 'posix_venv': scheme for *note Python virtual environments: 111. on
     POSIX platforms; by default it is the same as 'posix_prefix'.

   - 'nt': scheme for Windows.  This is the default scheme used when
     Python or a component is installed.

   - 'nt_user': scheme for Windows, when the 'user' option is used.

   - 'nt_venv': scheme for *note Python virtual environments: 111. on
     Windows; by default it is the same as 'nt'.

   - 'venv': a scheme with values from either 'posix_venv' or 'nt_venv'
     depending on the platform Python runs on.

   - 'osx_framework_user': scheme for macOS, when the 'user' option is
     used.

Each scheme is itself composed of a series of paths and each path has a
unique identifier.  Python currently uses eight paths:

   - 'stdlib': directory containing the standard Python library files
     that are not platform-specific.

   - 'platstdlib': directory containing the standard Python library
     files that are platform-specific.

   - 'platlib': directory for site-specific, platform-specific files.

   - 'purelib': directory for site-specific, non-platform-specific files
     (‘pure’ Python).

   - 'include': directory for non-platform-specific header files for the
     Python C-API.

   - 'platinclude': directory for platform-specific header files for the
     Python C-API.

   - 'scripts': directory for script files.

   - 'data': directory for data files.


File: python.info,  Node: User scheme,  Next: Home scheme,  Prev: Installation paths,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.3 User scheme
....................

This scheme is designed to be the most convenient solution for users
that don’t have write permission to the global site-packages directory
or don’t want to install into it.

Files will be installed into subdirectories of *note site.USER_BASE:
1366. (written as ‘`userbase'’ hereafter).  This scheme installs pure
Python modules and extension modules in the same location (also known as
*note site.USER_SITE: 1edd.).

* Menu:

* posix_user::
* nt_user::
* osx_framework_user::


File: python.info,  Node: posix_user,  Next: nt_user,  Up: User scheme

5.29.3.4 ‘posix_user’
.....................

Path               Installation directory
                   
-----------------------------------------------------------------------------------
                   
'stdlib'           ‘`userbase'/lib/python`X.Y'’
                   
                   
'platstdlib'       ‘`userbase'/lib/python`X.Y'’
                   
                   
'platlib'          ‘`userbase'/lib/python`X.Y'/site-packages’
                   
                   
'purelib'          ‘`userbase'/lib/python`X.Y'/site-packages’
                   
                   
'include'          ‘`userbase'/include/python`X.Y'’
                   
                   
'scripts'          ‘`userbase'/bin’
                   
                   
'data'             ‘`userbase'’
                   


File: python.info,  Node: nt_user,  Next: osx_framework_user,  Prev: posix_user,  Up: User scheme

5.29.3.5 ‘nt_user’
..................

Path               Installation directory
                   
-----------------------------------------------------------------------------------
                   
'stdlib'           ‘`userbase'\Python`XY'’
                   
                   
'platstdlib'       ‘`userbase'\Python`XY'’
                   
                   
'platlib'          ‘`userbase'\Python`XY'\site-packages’
                   
                   
'purelib'          ‘`userbase'\Python`XY'\site-packages’
                   
                   
'include'          ‘`userbase'\Python`XY'\Include’
                   
                   
'scripts'          ‘`userbase'\Python`XY'\Scripts’
                   
                   
'data'             ‘`userbase'’
                   


File: python.info,  Node: osx_framework_user,  Prev: nt_user,  Up: User scheme

5.29.3.6 ‘osx_framework_user’
.............................

Path               Installation directory
                   
-----------------------------------------------------------------------------------
                   
'stdlib'           ‘`userbase'/lib/python’
                   
                   
'platstdlib'       ‘`userbase'/lib/python’
                   
                   
'platlib'          ‘`userbase'/lib/python/site-packages’
                   
                   
'purelib'          ‘`userbase'/lib/python/site-packages’
                   
                   
'include'          ‘`userbase'/include/python`X.Y'’
                   
                   
'scripts'          ‘`userbase'/bin’
                   
                   
'data'             ‘`userbase'’
                   


File: python.info,  Node: Home scheme,  Next: Prefix scheme,  Prev: User scheme,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.7 Home scheme
....................

The idea behind the “home scheme” is that you build and maintain a
personal stash of Python modules.  This scheme’s name is derived from
the idea of a “home” directory on Unix, since it’s not unusual for a
Unix user to make their home directory have a layout similar to ‘/usr/’
or ‘/usr/local/’.  This scheme can be used by anyone, regardless of the
operating system they are installing for.

* Menu:

* posix_home::


File: python.info,  Node: posix_home,  Up: Home scheme

5.29.3.8 ‘posix_home’
.....................

Path               Installation directory
                   
-----------------------------------------------------------------------------------
                   
'stdlib'           ‘`home'/lib/python’
                   
                   
'platstdlib'       ‘`home'/lib/python’
                   
                   
'platlib'          ‘`home'/lib/python’
                   
                   
'purelib'          ‘`home'/lib/python’
                   
                   
'include'          ‘`home'/include/python’
                   
                   
'platinclude'      ‘`home'/include/python’
                   
                   
'scripts'          ‘`home'/bin’
                   
                   
'data'             ‘`home'’
                   


File: python.info,  Node: Prefix scheme,  Next: Installation path functions,  Prev: Home scheme,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.9 Prefix scheme
......................

The “prefix scheme” is useful when you wish to use one Python
installation to perform the build/install (i.e., to run the setup
script), but install modules into the third-party module directory of a
different Python installation (or something that looks like a different
Python installation).  If this sounds a trifle unusual, it is—that’s why
the user and home schemes come before.  However, there are at least two
known cases where the prefix scheme will be useful.

First, consider that many Linux distributions put Python in ‘/usr’,
rather than the more traditional ‘/usr/local’.  This is entirely
appropriate, since in those cases Python is part of “the system” rather
than a local add-on.  However, if you are installing Python modules from
source, you probably want them to go in ‘/usr/local/lib/python2.`X'’
rather than ‘/usr/lib/python2.`X'’.

Another possibility is a network filesystem where the name used to write
to a remote directory is different from the name used to read it: for
example, the Python interpreter accessed as ‘/usr/local/bin/python’
might search for modules in ‘/usr/local/lib/python2.`X'’, but those
modules would have to be installed to, say,
‘/mnt/`@server'/export/lib/python2.`X'’.

* Menu:

* posix_prefix::
* nt::


File: python.info,  Node: posix_prefix,  Next: nt,  Up: Prefix scheme

5.29.3.10 ‘posix_prefix’
........................

Path               Installation directory
                   
----------------------------------------------------------------------------------
                   
'stdlib'           ‘`prefix'/lib/python`X.Y'’
                   
                   
'platstdlib'       ‘`prefix'/lib/python`X.Y'’
                   
                   
'platlib'          ‘`prefix'/lib/python`X.Y'/site-packages’
                   
                   
'purelib'          ‘`prefix'/lib/python`X.Y'/site-packages’
                   
                   
'include'          ‘`prefix'/include/python`X.Y'’
                   
                   
'platinclude'      ‘`prefix'/include/python`X.Y'’
                   
                   
'scripts'          ‘`prefix'/bin’
                   
                   
'data'             ‘`prefix'’
                   


File: python.info,  Node: nt,  Prev: posix_prefix,  Up: Prefix scheme

5.29.3.11 ‘nt’
..............

Path               Installation directory
                   
----------------------------------------------------------------------------------
                   
'stdlib'           ‘`prefix'\Lib’
                   
                   
'platstdlib'       ‘`prefix'\Lib’
                   
                   
'platlib'          ‘`prefix'\Lib\site-packages’
                   
                   
'purelib'          ‘`prefix'\Lib\site-packages’
                   
                   
'include'          ‘`prefix'\Include’
                   
                   
'platinclude'      ‘`prefix'\Include’
                   
                   
'scripts'          ‘`prefix'\Scripts’
                   
                   
'data'             ‘`prefix'’
                   


File: python.info,  Node: Installation path functions,  Next: Other functions<3>,  Prev: Prefix scheme,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.12 Installation path functions
.....................................

‘sysconfig’ provides some functions to determine these installation
paths.

 -- Function: sysconfig.get_scheme_names ()

     Return a tuple containing all schemes currently supported in
     ‘sysconfig’.

 -- Function: sysconfig.get_default_scheme ()

     Return the default scheme name for the current platform.

     Added in version 3.10: This function was previously named
     ‘_get_default_scheme()’ and considered an implementation detail.

     Changed in version 3.11: When Python runs from a virtual
     environment, the 'venv' scheme is returned.

 -- Function: sysconfig.get_preferred_scheme (key)

     Return a preferred scheme name for an installation layout specified
     by 'key'.

     'key' must be either ‘"prefix"’, ‘"home"’, or ‘"user"’.

     The return value is a scheme name listed in *note
     get_scheme_names(): 4632.  It can be passed to ‘sysconfig’
     functions that take a 'scheme' argument, such as *note get_paths():
     128a.

     Added in version 3.10.

     Changed in version 3.11: When Python runs from a virtual
     environment and ‘key="prefix"’, the 'venv' scheme is returned.

 -- Function: sysconfig._get_preferred_schemes ()

     Return a dict containing preferred scheme names on the current
     platform.  Python implementers and redistributors may add their
     preferred schemes to the ‘_INSTALL_SCHEMES’ module-level global
     value, and modify this function to return those scheme names, to
     e.g.  provide different schemes for system and language package
     managers to use, so packages installed by either do not mix with
     those by the other.

     End users should not use this function, but *note
     get_default_scheme(): 195a. and *note get_preferred_scheme(): 693.
     instead.

     Added in version 3.10.

 -- Function: sysconfig.get_path_names ()

     Return a tuple containing all path names currently supported in
     ‘sysconfig’.

 -- Function: sysconfig.get_path (name[, scheme[, vars[, expand]]])

     Return an installation path corresponding to the path 'name', from
     the install scheme named 'scheme'.

     'name' has to be a value from the list returned by *note
     get_path_names(): 4634.

     ‘sysconfig’ stores installation paths corresponding to each path
     name, for each platform, with variables to be expanded.  For
     instance the 'stdlib' path for the 'nt' scheme is: ‘{base}/Lib’.

     ‘get_path()’ will use the variables returned by *note
     get_config_vars(): 1069. to expand the path.  All variables have
     default values for each platform so one may call this function and
     get the default value.

     If 'scheme' is provided, it must be a value from the list returned
     by *note get_scheme_names(): 4632.  Otherwise, the default scheme
     for the current platform is used.

     If 'vars' is provided, it must be a dictionary of variables that
     will update the dictionary returned by *note get_config_vars():
     1069.

     If 'expand' is set to ‘False’, the path will not be expanded using
     the variables.

     If 'name' is not found, raise a *note KeyError: 345.

 -- Function: sysconfig.get_paths ([scheme[, vars[, expand]]])

     Return a dictionary containing all installation paths corresponding
     to an installation scheme.  See *note get_path(): 1378. for more
     information.

     If 'scheme' is not provided, will use the default scheme for the
     current platform.

     If 'vars' is provided, it must be a dictionary of variables that
     will update the dictionary used to expand the paths.

     If 'expand' is set to false, the paths will not be expanded.

     If 'scheme' is not an existing scheme, ‘get_paths()’ will raise a
     *note KeyError: 345.


File: python.info,  Node: Other functions<3>,  Next: Command-line usage<4>,  Prev: Installation path functions,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.13 Other functions
.........................

 -- Function: sysconfig.get_python_version ()

     Return the ‘MAJOR.MINOR’ Python version number as a string.
     Similar to ‘'%d.%d' % sys.version_info[:2]’.

 -- Function: sysconfig.get_platform ()

     Return a string that identifies the current platform.

     This is used mainly to distinguish platform-specific build
     directories and platform-specific built distributions.  Typically
     includes the OS name and version and the architecture (as supplied
     by *note os.uname(): 115a.), although the exact information
     included depends on the OS; e.g., on Linux, the kernel version
     isn’t particularly important.

     Examples of returned values:

     Windows:

        - win-amd64 (64-bit Windows on AMD64, aka x86_64, Intel64, and
          EM64T)

        - win-arm64 (64-bit Windows on ARM64, aka AArch64)

        - win32 (all others - specifically, sys.platform is returned)

     POSIX based OS:

        - linux-x86_64

        - macosx-15.5-arm64

        - macosx-26.0-universal2 (macOS on Apple Silicon or Intel)

        - android-24-arm64_v8a

     For other non-POSIX platforms, currently just returns *note
     sys.platform: a9c.

 -- Function: sysconfig.is_python_build ()

     Return ‘True’ if the running Python interpreter was built from
     source and is being run from its built location, and not from a
     location resulting from e.g.  running ‘make install’ or installing
     via a binary installer.

 -- Function: sysconfig.parse_config_h (fp[, vars])

     Parse a ‘config.h’-style file.

     'fp' is a file-like object pointing to the ‘config.h’-like file.

     A dictionary containing name/value pairs is returned.  If an
     optional dictionary is passed in as the second argument, it is used
     instead of a new dictionary, and updated with the values read in
     the file.

 -- Function: sysconfig.get_config_h_filename ()

     Return the path of ‘pyconfig.h’.

 -- Function: sysconfig.get_makefile_filename ()

     Return the path of ‘Makefile’.


File: python.info,  Node: Command-line usage<4>,  Prev: Other functions<3>,  Up: sysconfig — Provide access to Python’s configuration information

5.29.3.14 Command-line usage
............................

You can use ‘sysconfig’ as a script with Python’s '-m' option:

     $ python -m sysconfig
     Platform: "macosx-10.4-i386"
     Python version: "3.2"
     Current installation scheme: "posix_prefix"

     Paths:
             data = "/usr/local"
             include = "/Users/tarek/Dev/svn.python.org/py3k/Include"
             platinclude = "."
             platlib = "/usr/local/lib/python3.2/site-packages"
             platstdlib = "/usr/local/lib/python3.2"
             purelib = "/usr/local/lib/python3.2/site-packages"
             scripts = "/usr/local/bin"
             stdlib = "/usr/local/lib/python3.2"

     Variables:
             AC_APPLE_UNIVERSAL_BUILD = "0"
             AIX_GENUINE_CPLUSPLUS = "0"
             AR = "ar"
             ARFLAGS = "rc"
             ...

This call will print in the standard output the information returned by
*note get_platform(): 1288, *note get_python_version(): 1289, *note
get_path(): 1378. and *note get_config_vars(): 1069.


File: python.info,  Node: builtins — Built-in objects,  Next: __main__ — Top-level code environment,  Prev: sysconfig — Provide access to Python’s configuration information,  Up: Python Runtime Services

5.29.4 ‘builtins’ — Built-in objects
------------------------------------

__________________________________________________________________

This module provides direct access to all ‘built-in’ identifiers of
Python; for example, ‘builtins.open’ is the full name for the built-in
function *note open(): 51f.

This module is not normally accessed explicitly by most applications,
but can be useful in modules that provide objects with the same name as
a built-in value, but in which the built-in of that name is also needed.
For example, in a module that wants to implement an *note open(): 51f.
function that wraps the built-in ‘open()’, this module can be used
directly:

     import builtins

     def open(path):
         f = builtins.open(path, 'r')
         return UpperCaser(f)

     class UpperCaser:
         '''Wrapper around a file that converts output to uppercase.'''

         def __init__(self, f):
             self._f = f

         def read(self, count=-1):
             return self._f.read(count).upper()

         # ...

As an implementation detail, most modules have the name ‘__builtins__’
made available as part of their globals.  The value of ‘__builtins__’ is
normally either this module or the value of this module’s *note
__dict__: 55e. attribute.  Since this is an implementation detail, it
may not be used by alternate implementations of Python.

See also
........

   * *note Built-in Constants: 233d.

   * *note Built-in Exceptions: 19cc.

   * *note Built-in Functions: 12a3.

   * *note Built-in Types: 2345.


File: python.info,  Node: __main__ — Top-level code environment,  Next: warnings — Warning control,  Prev: builtins — Built-in objects,  Up: Python Runtime Services

5.29.5 ‘__main__’ — Top-level code environment
----------------------------------------------

__________________________________________________________________

In Python, the special name ‘__main__’ is used for two important
constructs:

  1. the name of the top-level environment of the program, which can be
     checked using the ‘__name__ == '__main__'’ expression; and

  2. the ‘__main__.py’ file in Python packages.

Both of these mechanisms are related to Python modules; how users
interact with them and how they interact with each other.  They are
explained in detail below.  If you’re new to Python modules, see the
tutorial section *note Modules: 1df4. for an introduction.

* Menu:

* __name__ == '__main__'::
* __main__.py in Python Packages: __main__ py in Python Packages.
* import __main__::


File: python.info,  Node: __name__ == '__main__',  Next: __main__ py in Python Packages,  Up: __main__ — Top-level code environment

5.29.5.1 ‘__name__ == '__main__'’
.................................

When a Python module or package is imported, ‘__name__’ is set to the
module’s name.  Usually, this is the name of the Python file itself
without the ‘.py’ extension:

     >>> import configparser
     >>> configparser.__name__
     'configparser'

If the file is part of a package, ‘__name__’ will also include the
parent package’s path:

     >>> from concurrent.futures import process
     >>> process.__name__
     'concurrent.futures.process'

However, if the module is executed in the top-level code environment,
its ‘__name__’ is set to the string ‘'__main__'’.

* Menu:

* What is the “top-level code environment”?::
* Idiomatic Usage::
* Packaging Considerations::


File: python.info,  Node: What is the “top-level code environment”?,  Next: Idiomatic Usage,  Up: __name__ == '__main__'

5.29.5.2 What is the “top-level code environment”?
..................................................

‘__main__’ is the name of the environment where top-level code is run.
“Top-level code” is the first user-specified Python module that starts
running.  It’s “top-level” because it imports all other modules that the
program needs.  Sometimes “top-level code” is called an 'entry point' to
the application.

The top-level code environment can be:

   * the scope of an interactive prompt:

          >>> __name__
          '__main__'

   * the Python module passed to the Python interpreter as a file
     argument:

          $ python helloworld.py
          Hello, world!

   * the Python module or package passed to the Python interpreter with
     the *note -m: 5e4. argument:

          $ python -m tarfile
          usage: tarfile.py [-h] [-v] (...)

   * Python code read by the Python interpreter from standard input:

          $ echo "import this" | python
          The Zen of Python, by Tim Peters

          Beautiful is better than ugly.
          Explicit is better than implicit.
          ...

   * Python code passed to the Python interpreter with the *note -c:
     5e3. argument:

          $ python -c "import this"
          The Zen of Python, by Tim Peters

          Beautiful is better than ugly.
          Explicit is better than implicit.
          ...

In each of these situations, the top-level module’s ‘__name__’ is set to
‘'__main__'’.

As a result, a module can discover whether or not it is running in the
top-level environment by checking its own ‘__name__’, which allows a
common idiom for conditionally executing code when the module is not
initialized from an import statement:

     if __name__ == '__main__':
         # Execute when the module is not initialized from an import statement.
         ...

See also
........

For a more detailed look at how ‘__name__’ is set in all situations, see
the tutorial section *note Modules: 1df4.


File: python.info,  Node: Idiomatic Usage,  Next: Packaging Considerations,  Prev: What is the “top-level code environment”?,  Up: __name__ == '__main__'

5.29.5.3 Idiomatic Usage
........................

Some modules contain code that is intended for script use only, like
parsing command-line arguments or fetching data from standard input.  If
a module like this was imported from a different module, for example to
unit test it, the script code would unintentionally execute as well.

This is where using the ‘if __name__ == '__main__'’ code block comes in
handy.  Code within this block won’t run unless the module is executed
in the top-level environment.

Putting as few statements as possible in the block below ‘if __name__ ==
'__main__'’ can improve code clarity and correctness.  Most often, a
function named ‘main’ encapsulates the program’s primary behavior:

     # echo.py

     import shlex
     import sys

     def echo(phrase: str) -> None:
        """A dummy wrapper around print."""
        # for demonstration purposes, you can imagine that there is some
        # valuable and reusable logic inside this function
        print(phrase)

     def main() -> int:
         """Echo the input arguments to standard output"""
         phrase = shlex.join(sys.argv)
         echo(phrase)
         return 0

     if __name__ == '__main__':
         sys.exit(main())  # next section explains the use of sys.exit

Note that if the module didn’t encapsulate code inside the ‘main’
function but instead put it directly within the ‘if __name__ ==
'__main__'’ block, the ‘phrase’ variable would be global to the entire
module.  This is error-prone as other functions within the module could
be unintentionally using the global variable instead of a local name.  A
‘main’ function solves this problem.

Using a ‘main’ function has the added benefit of the ‘echo’ function
itself being isolated and importable elsewhere.  When ‘echo.py’ is
imported, the ‘echo’ and ‘main’ functions will be defined, but neither
of them will be called, because ‘__name__ != '__main__'’.


File: python.info,  Node: Packaging Considerations,  Prev: Idiomatic Usage,  Up: __name__ == '__main__'

5.29.5.4 Packaging Considerations
.................................

‘main’ functions are often used to create command-line tools by
specifying them as entry points for console scripts.  When this is done,
pip(1) inserts the function call into a template script, where the
return value of ‘main’ is passed into *note sys.exit(): 1394.  For
example:

     sys.exit(main())

Since the call to ‘main’ is wrapped in *note sys.exit(): 1394, the
expectation is that your function will return some value acceptable as
an input to ‘sys.exit()’; typically, an integer or ‘None’ (which is
implicitly returned if your function does not have a return statement).

By proactively following this convention ourselves, our module will have
the same behavior when run directly (i.e.  ‘python echo.py’) as it will
have if we later package it as a console script entry-point in a
pip-installable package.

In particular, be careful about returning strings from your ‘main’
function.  *note sys.exit(): 1394. will interpret a string argument as a
failure message, so your program will have an exit code of ‘1’,
indicating failure, and the string will be written to *note sys.stderr:
943.  The ‘echo.py’ example from earlier exemplifies using the
‘sys.exit(main())’ convention.

See also
........

Python Packaging User Guide(2) contains a collection of tutorials and
references on how to distribute and install Python packages with modern
tools.

   ---------- Footnotes ----------

   (1) https://pip.pypa.io/

   (2) https://packaging.python.org/


File: python.info,  Node: __main__ py in Python Packages,  Next: import __main__,  Prev: __name__ == '__main__',  Up: __main__ — Top-level code environment

5.29.5.5 ‘__main__.py’ in Python Packages
.........................................

If you are not familiar with Python packages, see section *note
Packages: 1e05. of the tutorial.  Most commonly, the ‘__main__.py’ file
is used to provide a command-line interface for a package.  Consider the
following hypothetical package, “bandclass”:

     bandclass
       ├── __init__.py
       ├── __main__.py
       └── student.py

‘__main__.py’ will be executed when the package itself is invoked
directly from the command line using the *note -m: 5e4. flag.  For
example:

     $ python -m bandclass

This command will cause ‘__main__.py’ to run.  How you utilize this
mechanism will depend on the nature of the package you are writing, but
in this hypothetical case, it might make sense to allow the teacher to
search for students:

     # bandclass/__main__.py

     import sys
     from .student import search_students

     student_name = sys.argv[1] if len(sys.argv) >= 2 else ''
     print(f'Found student: {search_students(student_name)}')

Note that ‘from .student import search_students’ is an example of a
relative import.  This import style can be used when referencing modules
within a package.  For more details, see *note Intra-package References:
1e0a. in the *note Modules: 1df4. section of the tutorial.

* Menu:

* Idiomatic Usage: Idiomatic Usage<2>.


File: python.info,  Node: Idiomatic Usage<2>,  Up: __main__ py in Python Packages

5.29.5.6 Idiomatic Usage
........................

The content of ‘__main__.py’ typically isn’t fenced with an ‘if __name__
== '__main__'’ block.  Instead, those files are kept short and import
functions to execute from other modules.  Those other modules can then
be easily unit-tested and are properly reusable.

If used, an ‘if __name__ == '__main__'’ block will still work as
expected for a ‘__main__.py’ file within a package, because its
‘__name__’ attribute will include the package’s path if imported:

     >>> import asyncio.__main__
     >>> asyncio.__main__.__name__
     'asyncio.__main__'

This won’t work for ‘__main__.py’ files in the root directory of a
‘.zip’ file though.  Hence, for consistency, a minimal ‘__main__.py’
without a ‘__name__’ check is preferred.

See also
........

See *note venv: 111. for an example of a package with a minimal
‘__main__.py’ in the standard library.  It doesn’t contain a ‘if
__name__ == '__main__'’ block.  You can invoke it with ‘python -m venv
[directory]’.

See *note runpy: be. for more details on the *note -m: 5e4. flag to the
interpreter executable.

See *note zipapp: 130. for how to run applications packaged as '.zip'
files.  In this case Python looks for a ‘__main__.py’ file in the root
directory of the archive.


File: python.info,  Node: import __main__,  Prev: __main__ py in Python Packages,  Up: __main__ — Top-level code environment

5.29.5.7 ‘import __main__’
..........................

Regardless of which module a Python program was started with, other
modules running within that same program can import the top-level
environment’s scope (*note namespace: 1df5.) by importing the ‘__main__’
module.  This doesn’t import a ‘__main__.py’ file but rather whichever
module that received the special name ‘'__main__'’.

Here is an example module that consumes the ‘__main__’ namespace:

     # namely.py

     import __main__

     def did_user_define_their_name():
         return 'my_name' in dir(__main__)

     def print_user_name():
         if not did_user_define_their_name():
             raise ValueError('Define the variable `my_name`!')

         if '__file__' in dir(__main__):
             print(__main__.my_name, "found in file", __main__.__file__)
         else:
             print(__main__.my_name)

Example usage of this module could be as follows:

     # start.py

     import sys

     from namely import print_user_name

     # my_name = "Dinsdale"

     def main():
         try:
             print_user_name()
         except ValueError as ve:
             return str(ve)

     if __name__ == "__main__":
         sys.exit(main())

Now, if we started our program, the result would look like this:

     $ python start.py
     Define the variable `my_name`!

The exit code of the program would be 1, indicating an error.
Uncommenting the line with ‘my_name = "Dinsdale"’ fixes the program and
now it exits with status code 0, indicating success:

     $ python start.py
     Dinsdale found in file /path/to/start.py

Note that importing ‘__main__’ doesn’t cause any issues with
unintentionally running top-level code meant for script use which is put
in the ‘if __name__ == "__main__"’ block of the ‘start’ module.  Why
does this work?

Python inserts an empty ‘__main__’ module in *note sys.modules: 1655. at
interpreter startup, and populates it by running top-level code.  In our
example this is the ‘start’ module which runs line by line and imports
‘namely’.  In turn, ‘namely’ imports ‘__main__’ (which is really
‘start’).  That’s an import cycle!  Fortunately, since the partially
populated ‘__main__’ module is present in ‘sys.modules’, Python passes
that to ‘namely’.  See *note Special considerations for __main__: 21be.
in the import system’s reference for details on how this works.

The Python REPL is another example of a “top-level environment”, so
anything defined in the REPL becomes part of the ‘__main__’ scope:

     >>> import namely
     >>> namely.did_user_define_their_name()
     False
     >>> namely.print_user_name()
     Traceback (most recent call last):
     ...
     ValueError: Define the variable `my_name`!
     >>> my_name = 'Jabberwocky'
     >>> namely.did_user_define_their_name()
     True
     >>> namely.print_user_name()
     Jabberwocky

Note that in this case the ‘__main__’ scope doesn’t contain a ‘__file__’
attribute as it’s interactive.

The ‘__main__’ scope is used in the implementation of *note pdb: a5. and
*note rlcompleter: bd.


File: python.info,  Node: warnings — Warning control,  Next: dataclasses — Data Classes,  Prev: __main__ — Top-level code environment,  Up: Python Runtime Services

5.29.6 ‘warnings’ — Warning control
-----------------------------------

'Source code:' Lib/warnings.py(1)

__________________________________________________________________

Warning messages are typically issued in situations where it is useful
to alert the user of some condition in a program, where that condition
(normally) doesn’t warrant raising an exception and terminating the
program.  For example, one might want to issue a warning when a program
uses an obsolete module.

Python programmers issue warnings by calling the *note warn(): 1569.
function defined in this module.  (C programmers use *note
PyErr_WarnEx(): 149b.; see *note Exception Handling: 464d. for details).

Warning messages are normally written to *note sys.stderr: 943, but
their disposition can be changed flexibly, from ignoring all warnings to
turning them into exceptions.  The disposition of warnings can vary
based on the *note warning category: 246b, the text of the warning
message, and the source location where it is issued.  Repetitions of a
particular warning for the same source location are typically
suppressed.

There are two stages in warning control: first, each time a warning is
issued, a determination is made whether a message should be issued or
not; next, if a message is to be issued, it is formatted and printed
using a user-settable hook.

The determination whether to issue a warning message is controlled by
the *note warning filter: 8d2, which is a sequence of matching rules and
actions.  Rules can be added to the filter by calling *note
filterwarnings(): 14f8. and reset to its default state by calling *note
resetwarnings(): 464e.

The printing of warning messages is done by calling *note showwarning():
464f, which may be overridden; the default implementation of this
function formats the message by calling *note formatwarning(): 1ba6,
which is also available for use by custom implementations.

See also
........

*note logging.captureWarnings(): 2ea1. allows you to handle all warnings
with the standard logging infrastructure.

* Menu:

* Warning Categories::
* The Warnings Filter::
* Temporarily Suppressing Warnings::
* Testing Warnings::
* Updating Code For New Versions of Dependencies::
* Available Functions::
* Available Context Managers::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/warnings.py


File: python.info,  Node: Warning Categories,  Next: The Warnings Filter,  Up: warnings — Warning control

5.29.6.1 Warning Categories
...........................

There are a number of built-in exceptions that represent warning
categories.  This categorization is useful to be able to filter out
groups of warnings.

While these are technically *note built-in exceptions: 2469, they are
documented here, because conceptually they belong to the warnings
mechanism.

User code can define additional warning categories by subclassing one of
the standard warning categories.  A warning category must always be a
subclass of the *note Warning: 246c. class.

The following warnings category classes are currently defined:

Class                                  Description
                                       
-------------------------------------------------------------------------------------------
                                       
*note Warning: 246c.                   This is the base class of all warning category
                                       classes.  It is a subclass of
                                       *note Exception: 9e5.
                                       
                                       
*note UserWarning: 246d.               The default category for *note warn(): 1569.
                                       
                                       
*note DeprecationWarning: 1a5.         Base category for warnings about deprecated
                                       features when those warnings are intended for
                                       other Python developers (ignored by default,
                                       unless triggered by code in ‘__main__’).
                                       
                                       
*note SyntaxWarning: 469.              Base category for warnings about dubious
                                       syntactic features (typically emitted when
                                       compiling Python source code, and hence may not
                                       be suppressed by runtime filters)
                                       
                                       
*note RuntimeWarning: 1bd.             Base category for warnings about dubious runtime
                                       features.
                                       
                                       
*note FutureWarning: 418.              Base category for warnings about deprecated
                                       features when those warnings are intended for end
                                       users of applications that are written in Python.
                                       
                                       
*note PendingDeprecationWarning: 8d1.  Base category for warnings about features that
                                       will be deprecated in the future (ignored by
                                       default).
                                       
                                       
*note ImportWarning: 4fd.              Base category for warnings triggered during the
                                       process of importing a module (ignored by
                                       default).
                                       
                                       
*note UnicodeWarning: 1472.            Base category for warnings related to Unicode.
                                       
                                       
*note BytesWarning: c43.               Base category for warnings related to
                                       *note bytes: 1c2. and *note bytearray: 2ea.
                                       
                                       
*note ResourceWarning: 244.            Base category for warnings related to resource
                                       usage (ignored by default).
                                       

Changed in version 3.7: Previously *note DeprecationWarning: 1a5. and
*note FutureWarning: 418. were distinguished based on whether a feature
was being removed entirely or changing its behaviour.  They are now
distinguished based on their intended audience and the way they’re
handled by the default warnings filters.


File: python.info,  Node: The Warnings Filter,  Next: Temporarily Suppressing Warnings,  Prev: Warning Categories,  Up: warnings — Warning control

5.29.6.2 The Warnings Filter
............................

The warnings filter controls whether warnings are ignored, displayed, or
turned into errors (raising an exception).

Conceptually, the warnings filter maintains an ordered list of filter
specifications; any specific warning is matched against each filter
specification in the list in turn until a match is found; the filter
determines the disposition of the match.  Each entry is a tuple of the
form ('action', 'message', 'category', 'module', 'lineno'), where:

   * 'action' is one of the following strings:

     Value               Disposition
                         
     -----------------------------------------------------------------------
                         
     ‘"default"’         print the first occurrence of matching warnings
                         for each location (module + line number) where
                         the warning is issued
                         
                         
     ‘"error"’           turn matching warnings into exceptions
                         
                         
     ‘"ignore"’          never print matching warnings
                         
                         
     ‘"always"’          always print matching warnings
                         
                         
     ‘"module"’          print the first occurrence of matching warnings
                         for each module where the warning is issued
                         (regardless of line number)
                         
                         
     ‘"once"’            print only the first occurrence of matching
                         warnings, regardless of location
                         

   * 'message' is a string containing a regular expression that the
     start of the warning message must match, case-insensitively.  In
     *note -W: 8d0. and *note PYTHONWARNINGS: bc8, 'message' is a
     literal string that the start of the warning message must contain
     (case-insensitively), ignoring any whitespace at the start or end
     of 'message'.

   * 'category' is a class (a subclass of *note Warning: 246c.) of which
     the warning category must be a subclass in order to match.

   * 'module' is a string containing a regular expression that the start
     of the fully qualified module name must match, case-sensitively.
     In *note -W: 8d0. and *note PYTHONWARNINGS: bc8, 'module' is a
     literal string that the fully qualified module name must be equal
     to (case-sensitively), ignoring any whitespace at the start or end
     of 'module'.

   * 'lineno' is an integer that the line number where the warning
     occurred must match, or ‘0’ to match all line numbers.

Since the *note Warning: 246c. class is derived from the built-in *note
Exception: 9e5. class, to turn a warning into an error we simply raise
‘category(message)’.

If a warning is reported and doesn’t match any registered filter then
the “default” action is applied (hence its name).

* Menu:

* Repeated Warning Suppression Criteria::
* Describing Warning Filters::
* Default Warning Filter::
* Overriding the default filter::


File: python.info,  Node: Repeated Warning Suppression Criteria,  Next: Describing Warning Filters,  Up: The Warnings Filter

5.29.6.3 Repeated Warning Suppression Criteria
..............................................

The filters that suppress repeated warnings apply the following criteria
to determine if a warning is considered a repeat:

   - ‘"default"’: A warning is considered a repeat only if the
     ('message', 'category', 'module', 'lineno') are all the same.

   - ‘"module"’: A warning is considered a repeat if the ('message',
     'category', 'module') are the same, ignoring the line number.

   - ‘"once"’: A warning is considered a repeat if the ('message',
     'category') are the same, ignoring the module and line number.


File: python.info,  Node: Describing Warning Filters,  Next: Default Warning Filter,  Prev: Repeated Warning Suppression Criteria,  Up: The Warnings Filter

5.29.6.4 Describing Warning Filters
...................................

The warnings filter is initialized by *note -W: 8d0. options passed to
the Python interpreter command line and the *note PYTHONWARNINGS: bc8.
environment variable.  The interpreter saves the arguments for all
supplied entries without interpretation in *note sys.warnoptions: 3b3.;
the ‘warnings’ module parses these when it is first imported (invalid
options are ignored, after printing a message to *note sys.stderr:
943.).

Individual warnings filters are specified as a sequence of fields
separated by colons:

     action:message:category:module:line

The meaning of each of these fields is as described in *note The
Warnings Filter: 8d2.  When listing multiple filters on a single line
(as for *note PYTHONWARNINGS: bc8.), the individual filters are
separated by commas and the filters listed later take precedence over
those listed before them (as they’re applied left-to-right, and the most
recently applied filters take precedence over earlier ones).

Commonly used warning filters apply to either all warnings, warnings in
a particular category, or warnings raised by particular modules or
packages.  Some examples:

     default                      # Show all warnings (even those ignored by default)
     ignore                       # Ignore all warnings
     error                        # Convert all warnings to errors
     error::ResourceWarning       # Treat ResourceWarning messages as errors
     default::DeprecationWarning  # Show DeprecationWarning messages
     ignore,default:::mymodule    # Only report warnings triggered by "mymodule"
     error:::mymodule             # Convert warnings to errors in "mymodule"


File: python.info,  Node: Default Warning Filter,  Next: Overriding the default filter,  Prev: Describing Warning Filters,  Up: The Warnings Filter

5.29.6.5 Default Warning Filter
...............................

By default, Python installs several warning filters, which can be
overridden by the *note -W: 8d0. command-line option, the *note
PYTHONWARNINGS: bc8. environment variable and calls to *note
filterwarnings(): 14f8.

In regular release builds, the default warning filter has the following
entries (in order of precedence):

     default::DeprecationWarning:__main__
     ignore::DeprecationWarning
     ignore::PendingDeprecationWarning
     ignore::ImportWarning
     ignore::ResourceWarning

In a *note debug build: 1f9, the list of default warning filters is
empty.

Changed in version 3.2: *note DeprecationWarning: 1a5. is now ignored by
default in addition to *note PendingDeprecationWarning: 8d1.

Changed in version 3.7: *note DeprecationWarning: 1a5. is once again
shown by default when triggered directly by code in ‘__main__’.

Changed in version 3.7: *note BytesWarning: c43. no longer appears in
the default filter list and is instead configured via *note
sys.warnoptions: 3b3. when *note -b: 5e6. is specified twice.


File: python.info,  Node: Overriding the default filter,  Prev: Default Warning Filter,  Up: The Warnings Filter

5.29.6.6 Overriding the default filter
......................................

Developers of applications written in Python may wish to hide 'all'
Python level warnings from their users by default, and only display them
when running tests or otherwise working on the application.  The *note
sys.warnoptions: 3b3. attribute used to pass filter configurations to
the interpreter can be used as a marker to indicate whether or not
warnings should be disabled:

     import sys

     if not sys.warnoptions:
         import warnings
         warnings.simplefilter("ignore")

Developers of test runners for Python code are advised to instead ensure
that 'all' warnings are displayed by default for the code under test,
using code like:

     import sys

     if not sys.warnoptions:
         import os, warnings
         warnings.simplefilter("default") # Change the filter in this process
         os.environ["PYTHONWARNINGS"] = "default" # Also affect subprocesses

Finally, developers of interactive shells that run user code in a
namespace other than ‘__main__’ are advised to ensure that *note
DeprecationWarning: 1a5. messages are made visible by default, using
code like the following (where ‘user_ns’ is the module used to execute
code entered interactively):

     import warnings
     warnings.filterwarnings("default", category=DeprecationWarning,
                                        module=user_ns.get("__name__"))


File: python.info,  Node: Temporarily Suppressing Warnings,  Next: Testing Warnings,  Prev: The Warnings Filter,  Up: warnings — Warning control

5.29.6.7 Temporarily Suppressing Warnings
.........................................

If you are using code that you know will raise a warning, such as a
deprecated function, but do not want to see the warning (even when
warnings have been explicitly configured via the command line), then it
is possible to suppress the warning using the *note catch_warnings: 587.
context manager:

     import warnings

     def fxn():
         warnings.warn("deprecated", DeprecationWarning)

     with warnings.catch_warnings():
         warnings.simplefilter("ignore")
         fxn()

While within the context manager all warnings will simply be ignored.
This allows you to use known-deprecated code without having to see the
warning while not suppressing the warning for other code that might not
be aware of its use of deprecated code.  Note: this can only be
guaranteed in a single-threaded application.  If two or more threads use
the *note catch_warnings: 587. context manager at the same time, the
behavior is undefined.


File: python.info,  Node: Testing Warnings,  Next: Updating Code For New Versions of Dependencies,  Prev: Temporarily Suppressing Warnings,  Up: warnings — Warning control

5.29.6.8 Testing Warnings
.........................

To test warnings raised by code, use the *note catch_warnings: 587.
context manager.  With it you can temporarily mutate the warnings filter
to facilitate your testing.  For instance, do the following to capture
all raised warnings to check:

     import warnings

     def fxn():
         warnings.warn("deprecated", DeprecationWarning)

     with warnings.catch_warnings(record=True) as w:
         # Cause all warnings to always be triggered.
         warnings.simplefilter("always")
         # Trigger a warning.
         fxn()
         # Verify some things
         assert len(w) == 1
         assert issubclass(w[-1].category, DeprecationWarning)
         assert "deprecated" in str(w[-1].message)

One can also cause all warnings to be exceptions by using ‘error’
instead of ‘always’.  One thing to be aware of is that if a warning has
already been raised because of a ‘once’/‘default’ rule, then no matter
what filters are set the warning will not be seen again unless the
warnings registry related to the warning has been cleared.

Once the context manager exits, the warnings filter is restored to its
state when the context was entered.  This prevents tests from changing
the warnings filter in unexpected ways between tests and leading to
indeterminate test results.  The *note showwarning(): 464f. function in
the module is also restored to its original value.  Note: this can only
be guaranteed in a single-threaded application.  If two or more threads
use the *note catch_warnings: 587. context manager at the same time, the
behavior is undefined.

When testing multiple operations that raise the same kind of warning, it
is important to test them in a manner that confirms each operation is
raising a new warning (e.g.  set warnings to be raised as exceptions and
check the operations raise exceptions, check that the length of the
warning list continues to increase after each operation, or else delete
the previous entries from the warnings list before each new operation).


File: python.info,  Node: Updating Code For New Versions of Dependencies,  Next: Available Functions,  Prev: Testing Warnings,  Up: warnings — Warning control

5.29.6.9 Updating Code For New Versions of Dependencies
.......................................................

Warning categories that are primarily of interest to Python developers
(rather than end users of applications written in Python) are ignored by
default.

Notably, this “ignored by default” list includes *note
DeprecationWarning: 1a5. (for every module except ‘__main__’), which
means developers should make sure to test their code with typically
ignored warnings made visible in order to receive timely notifications
of future breaking API changes (whether in the standard library or third
party packages).

In the ideal case, the code will have a suitable test suite, and the
test runner will take care of implicitly enabling all warnings when
running tests (the test runner provided by the *note unittest: 106.
module does this).

In less ideal cases, applications can be checked for use of deprecated
interfaces by passing *note -Wd: 8d0. to the Python interpreter (this is
shorthand for ‘-W default’) or setting ‘PYTHONWARNINGS=default’ in the
environment.  This enables default handling for all warnings, including
those that are ignored by default.  To change what action is taken for
encountered warnings you can change what argument is passed to ‘-W’
(e.g.  ‘-W error’).  See the ‘-W’ flag for more details on what is
possible.


File: python.info,  Node: Available Functions,  Next: Available Context Managers,  Prev: Updating Code For New Versions of Dependencies,  Up: warnings — Warning control

5.29.6.10 Available Functions
.............................

 -- Function: warnings.warn (message, category=None, stacklevel=1,
          source=None, *, skip_file_prefixes=())

     Issue a warning, or maybe ignore it or raise an exception.  The
     'category' argument, if given, must be a *note warning category
     class: 246b.; it defaults to *note UserWarning: 246d.
     Alternatively, 'message' can be a *note Warning: 246c. instance, in
     which case 'category' will be ignored and ‘message.__class__’ will
     be used.  In this case, the message text will be ‘str(message)’.
     This function raises an exception if the particular warning issued
     is changed into an error by the *note warnings filter: 8d2.  The
     'stacklevel' argument can be used by wrapper functions written in
     Python, like this:

          def deprecated_api(message):
              warnings.warn(message, DeprecationWarning, stacklevel=2)

     This makes the warning refer to ‘deprecated_api’’s caller, rather
     than to the source of ‘deprecated_api’ itself (since the latter
     would defeat the purpose of the warning message).

     The 'skip_file_prefixes' keyword argument can be used to indicate
     which stack frames are ignored when counting stack levels.  This
     can be useful when you want the warning to always appear at call
     sites outside of a package when a constant 'stacklevel' does not
     fit all call paths or is otherwise challenging to maintain.  If
     supplied, it must be a tuple of strings.  When prefixes are
     supplied, stacklevel is implicitly overridden to be ‘max(2,
     stacklevel)’.  To cause a warning to be attributed to the caller
     from outside of the current package you might write:

          # example/lower.py
          _warn_skips = (os.path.dirname(__file__),)

          def one_way(r_luxury_yacht=None, t_wobbler_mangrove=None):
              if r_luxury_yacht:
                  warnings.warn("Please migrate to t_wobbler_mangrove=.",
                                skip_file_prefixes=_warn_skips)

          # example/higher.py
          from . import lower

          def another_way(**kw):
              lower.one_way(**kw)

     This makes the warning refer to both the ‘example.lower.one_way()’
     and ‘example.higher.another_way()’ call sites only from calling
     code living outside of ‘example’ package.

     'source', if supplied, is the destroyed object which emitted a
     *note ResourceWarning: 244.

     Changed in version 3.6: Added 'source' parameter.

     Changed in version 3.12: Added 'skip_file_prefixes'.

 -- Function: warnings.warn_explicit (message, category, filename,
          lineno, module=None, registry=None, module_globals=None,
          source=None)

     This is a low-level interface to the functionality of *note warn():
     1569, passing in explicitly the message, category, filename and
     line number, and optionally other arguments.  'message' must be a
     string and 'category' a subclass of *note Warning: 246c. or
     'message' may be a ‘Warning’ instance, in which case 'category'
     will be ignored.

     'module', if supplied, should be the module name.  If no module is
     passed, the filename with ‘.py’ stripped is used.

     'registry', if supplied, should be the ‘__warningregistry__’
     dictionary of the module.  If no registry is passed, each warning
     is treated as the first occurrence, that is, filter actions
     ‘"default"’, ‘"module"’ and ‘"once"’ are handled as ‘"always"’.

     'module_globals', if supplied, should be the global namespace in
     use by the code for which the warning is issued.  (This argument is
     used to support displaying source for modules found in zipfiles or
     other non-filesystem import sources).

     'source', if supplied, is the destroyed object which emitted a
     *note ResourceWarning: 244.

     Changed in version 3.6: Add the 'source' parameter.

 -- Function: warnings.showwarning (message, category, filename, lineno,
          file=None, line=None)

     Write a warning to a file.  The default implementation calls
     ‘formatwarning(message, category, filename, lineno, line)’ and
     writes the resulting string to 'file', which defaults to *note
     sys.stderr: 943.  You may replace this function with any callable
     by assigning to ‘warnings.showwarning’.  'line' is a line of source
     code to be included in the warning message; if 'line' is not
     supplied, ‘showwarning()’ will try to read the line specified by
     'filename' and 'lineno'.

 -- Function: warnings.formatwarning (message, category, filename,
          lineno, line=None)

     Format a warning the standard way.  This returns a string which may
     contain embedded newlines and ends in a newline.  'line' is a line
     of source code to be included in the warning message; if 'line' is
     not supplied, ‘formatwarning()’ will try to read the line specified
     by 'filename' and 'lineno'.

 -- Function: warnings.filterwarnings (action, message='',
          category=Warning, module='', lineno=0, append=False)

     Insert an entry into the list of *note warnings filter
     specifications: 8d2.  The entry is inserted at the front by
     default; if 'append' is true, it is inserted at the end.  This
     checks the types of the arguments, compiles the 'message' and
     'module' regular expressions, and inserts them as a tuple in the
     list of warnings filters.  Entries closer to the front of the list
     override entries later in the list, if both match a particular
     warning.  Omitted arguments default to a value that matches
     everything.

 -- Function: warnings.simplefilter (action, category=Warning, lineno=0,
          append=False)

     Insert a simple entry into the list of *note warnings filter
     specifications: 8d2.  The meaning of the function parameters is as
     for *note filterwarnings(): 14f8, but regular expressions are not
     needed as the filter inserted always matches any message in any
     module as long as the category and line number match.

 -- Function: warnings.resetwarnings ()

     Reset the warnings filter.  This discards the effect of all
     previous calls to *note filterwarnings(): 14f8, including that of
     the *note -W: 8d0. command line options and calls to *note
     simplefilter(): 6c4.

 -- Function: @warnings.deprecated (msg, *, category=DeprecationWarning,
          stacklevel=1)

     Decorator to indicate that a class, function or overload is
     deprecated.

     When this decorator is applied to an object, deprecation warnings
     may be emitted at runtime when the object is used.  *note static
     type checkers: 26d. will also generate a diagnostic on usage of the
     deprecated object.

     Usage:

          from warnings import deprecated
          from typing import overload

          @deprecated("Use B instead")
          class A:
              pass

          @deprecated("Use g instead")
          def f():
              pass

          @overload
          @deprecated("int support is deprecated")
          def g(x: int) -> int: ...
          @overload
          def g(x: str) -> int: ...

     The warning specified by 'category' will be emitted at runtime on
     use of deprecated objects.  For functions, that happens on calls;
     for classes, on instantiation and on creation of subclasses.  If
     the 'category' is ‘None’, no warning is emitted at runtime.  The
     'stacklevel' determines where the warning is emitted.  If it is ‘1’
     (the default), the warning is emitted at the direct caller of the
     deprecated object; if it is higher, it is emitted further up the
     stack.  Static type checker behavior is not affected by the
     'category' and 'stacklevel' arguments.

     The deprecation message passed to the decorator is saved in the
     ‘__deprecated__’ attribute on the decorated object.  If applied to
     an overload, the decorator must be after the *note
     @~typing.overload: 41e8. decorator for the attribute to exist on
     the overload as returned by *note typing.get_overloads(): 6b1.

     Added in version 3.13: See PEP 702(1).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0702/


File: python.info,  Node: Available Context Managers,  Prev: Available Functions,  Up: warnings — Warning control

5.29.6.11 Available Context Managers
....................................

 -- Class: warnings.catch_warnings (*, record=False, module=None,
          action=None, category=Warning, lineno=0, append=False)

     A context manager that copies and, upon exit, restores the warnings
     filter and the *note showwarning(): 464f. function.  If the
     'record' argument is *note False: b4f. (the default) the context
     manager returns *note None: 678. on entry.  If 'record' is *note
     True: c2d, a list is returned that is progressively populated with
     objects as seen by a custom ‘showwarning()’ function (which also
     suppresses output to ‘sys.stdout’).  Each object in the list has
     attributes with the same names as the arguments to ‘showwarning()’.

     The 'module' argument takes a module that will be used instead of
     the module returned when you import ‘warnings’ whose filter will be
     protected.  This argument exists primarily for testing the
     ‘warnings’ module itself.

     If the 'action' argument is not ‘None’, the remaining arguments are
     passed to *note simplefilter(): 6c4. as if it were called
     immediately on entering the context.

     See *note The Warnings Filter: 8d2. for the meaning of the
     'category' and 'lineno' parameters.

          Note: The ‘catch_warnings’ manager works by replacing and then
          later restoring the module’s *note showwarning(): 464f.
          function and internal list of filter specifications.  This
          means the context manager is modifying global state and
          therefore is not thread-safe.

     Changed in version 3.11: Added the 'action', 'category', 'lineno',
     and 'append' parameters.


File: python.info,  Node: dataclasses — Data Classes,  Next: contextlib — Utilities for with-statement contexts,  Prev: warnings — Warning control,  Up: Python Runtime Services

5.29.7 ‘dataclasses’ — Data Classes
-----------------------------------

'Source code:' Lib/dataclasses.py(1)

__________________________________________________________________

This module provides a decorator and functions for automatically adding
generated *note special methods: 1a06. such as *note __init__(): 6b3.
and *note __repr__(): 61f. to user-defined classes.  It was originally
described in PEP 557(2).

The member variables to use in these generated methods are defined using
PEP 526(3) type annotations.  For example, this code:

     from dataclasses import dataclass

     @dataclass
     class InventoryItem:
         """Class for keeping track of an item in inventory."""
         name: str
         unit_price: float
         quantity_on_hand: int = 0

         def total_cost(self) -> float:
             return self.unit_price * self.quantity_on_hand

will add, among other things, a ‘__init__()’ that looks like:

     def __init__(self, name: str, unit_price: float, quantity_on_hand: int = 0):
         self.name = name
         self.unit_price = unit_price
         self.quantity_on_hand = quantity_on_hand

Note that this method is automatically added to the class: it is not
directly specified in the ‘InventoryItem’ definition shown above.

Added in version 3.7.

* Menu:

* Module contents: Module contents<5>.
* Post-init processing::
* Class variables::
* Init-only variables::
* Frozen instances::
* Inheritance: Inheritance<2>.
* Re-ordering of keyword-only parameters in __init__(): Re-ordering of keyword-only parameters in __init__.
* Default factory functions::
* Mutable default values::
* Descriptor-typed fields::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dataclasses.py

   (2) https://peps.python.org/pep-0557/

   (3) https://peps.python.org/pep-0526/


File: python.info,  Node: Module contents<5>,  Next: Post-init processing,  Up: dataclasses — Data Classes

5.29.7.1 Module contents
........................

 -- Function: @dataclasses.dataclass (*, init=True, repr=True, eq=True,
          order=False, unsafe_hash=False, frozen=False, match_args=True,
          kw_only=False, slots=False, weakref_slot=False)

     This function is a *note decorator: 734. that is used to add
     generated *note special methods: 1a06. to classes, as described
     below.

     The ‘@dataclass’ decorator examines the class to find ‘field’s.  A
     ‘field’ is defined as a class variable that has a *note type
     annotation: d7f.  With two exceptions described below, nothing in
     ‘@dataclass’ examines the type specified in the variable
     annotation.

     The order of the fields in all of the generated methods is the
     order in which they appear in the class definition.

     The ‘@dataclass’ decorator will add various “dunder” methods to the
     class, described below.  If any of the added methods already exist
     in the class, the behavior depends on the parameter, as documented
     below.  The decorator returns the same class that it is called on;
     no new class is created.

     If ‘@dataclass’ is used just as a simple decorator with no
     parameters, it acts as if it has the default values documented in
     this signature.  That is, these three uses of ‘@dataclass’ are
     equivalent:

          @dataclass
          class C:
              ...

          @dataclass()
          class C:
              ...

          @dataclass(init=True, repr=True, eq=True, order=False, unsafe_hash=False, frozen=False,
                     match_args=True, kw_only=False, slots=False, weakref_slot=False)
          class C:
              ...

     The parameters to ‘@dataclass’ are:

        - 'init': If true (the default), a *note __init__(): 6b3. method
          will be generated.

          If the class already defines ‘__init__()’, this parameter is
          ignored.

        - 'repr': If true (the default), a *note __repr__(): 61f. method
          will be generated.  The generated repr string will have the
          class name and the name and repr of each field, in the order
          they are defined in the class.  Fields that are marked as
          being excluded from the repr are not included.  For example:
          ‘InventoryItem(name='widget', unit_price=3.0,
          quantity_on_hand=10)’.

          If the class already defines ‘__repr__()’, this parameter is
          ignored.

        - 'eq': If true (the default), an *note __eq__(): b13. method
          will be generated.  This method compares the class as if it
          were a tuple of its fields, in order.  Both instances in the
          comparison must be of the identical type.

          If the class already defines ‘__eq__()’, this parameter is
          ignored.

        - 'order': If true (the default is ‘False’), *note __lt__():
          12e7, *note __le__(): 1354, *note __gt__(): 1355, and *note
          __ge__(): 1356. methods will be generated.  These compare the
          class as if it were a tuple of its fields, in order.  Both
          instances in the comparison must be of the identical type.  If
          'order' is true and 'eq' is false, a *note ValueError: 202. is
          raised.

          If the class already defines any of ‘__lt__()’, ‘__le__()’,
          ‘__gt__()’, or ‘__ge__()’, then *note TypeError: 2c3. is
          raised.

        - 'unsafe_hash': If true, force ‘dataclasses’ to create a *note
          __hash__(): b14. method, even though it may not be safe to do
          so.  Otherwise, generate a ‘__hash__()’ method according to
          how 'eq' and 'frozen' are set.  The default value is ‘False’.

          ‘__hash__()’ is used by built-in *note hash(): 5ee, and when
          objects are added to hashed collections such as dictionaries
          and sets.  Having a ‘__hash__()’ implies that instances of the
          class are immutable.  Mutability is a complicated property
          that depends on the programmer’s intent, the existence and
          behavior of ‘__eq__()’, and the values of the 'eq' and
          'frozen' flags in the ‘@dataclass’ decorator.

          By default, ‘@dataclass’ will not implicitly add a *note
          __hash__(): b14. method unless it is safe to do so.  Neither
          will it add or change an existing explicitly defined
          ‘__hash__()’ method.  Setting the class attribute ‘__hash__ =
          None’ has a specific meaning to Python, as described in the
          ‘__hash__()’ documentation.

          If ‘__hash__()’ is not explicitly defined, or if it is set to
          ‘None’, then ‘@dataclass’ 'may' add an implicit ‘__hash__()’
          method.  Although not recommended, you can force ‘@dataclass’
          to create a ‘__hash__()’ method with ‘unsafe_hash=True’.  This
          might be the case if your class is logically immutable but can
          still be mutated.  This is a specialized use case and should
          be considered carefully.

          Here are the rules governing implicit creation of a
          ‘__hash__()’ method.  Note that you cannot both have an
          explicit ‘__hash__()’ method in your dataclass and set
          ‘unsafe_hash=True’; this will result in a *note TypeError:
          2c3.

          If 'eq' and 'frozen' are both true, by default ‘@dataclass’
          will generate a ‘__hash__()’ method for you.  If 'eq' is true
          and 'frozen' is false, ‘__hash__()’ will be set to ‘None’,
          marking it unhashable (which it is, since it is mutable).  If
          'eq' is false, ‘__hash__()’ will be left untouched meaning the
          ‘__hash__()’ method of the superclass will be used (if the
          superclass is *note object: a9b, this means it will fall back
          to id-based hashing).

        - 'frozen': If true (the default is ‘False’), assigning to
          fields will generate an exception.  This emulates read-only
          frozen instances.  See the *note discussion: 4665. below.

          If *note __setattr__(): 20de. or *note __delattr__(): 20df. is
          defined in the class and 'frozen' is true, then *note
          TypeError: 2c3. is raised.

        - 'match_args': If true (the default is ‘True’), the *note
          __match_args__: 1a1c. tuple will be created from the list of
          non keyword-only parameters to the generated *note __init__():
          6b3. method (even if ‘__init__()’ is not generated, see
          above).  If false, or if ‘__match_args__’ is already defined
          in the class, then ‘__match_args__’ will not be generated.

          Added in version 3.10.

        - 'kw_only': If true (the default value is ‘False’), then all
          fields will be marked as keyword-only.  If a field is marked
          as keyword-only, then the only effect is that the *note
          __init__(): 6b3. parameter generated from a keyword-only field
          must be specified with a keyword when ‘__init__()’ is called.
          See the *note parameter: 20ae. glossary entry for details.
          Also see the *note KW_ONLY: 4666. section.

          Keyword-only fields are not included in ‘__match_args__’.

          Added in version 3.10.

        - 'slots': If true (the default is ‘False’), *note __slots__:
          153a. attribute will be generated and new class will be
          returned instead of the original one.  If ‘__slots__’ is
          already defined in the class, then *note TypeError: 2c3. is
          raised.

               Warning: Calling no-arg *note super(): 4de. in
               dataclasses using ‘slots=True’ will result in the
               following exception being raised: ‘TypeError: super(type,
               obj): obj must be an instance or subtype of type’.  The
               two-arg ‘super()’ is a valid workaround.  See gh-90562(1)
               for full details.

               Warning: Passing parameters to a base class *note
               __init_subclass__(): 634. when using ‘slots=True’ will
               result in a *note TypeError: 2c3.  Either use
               ‘__init_subclass__’ with no parameters or use default
               values as a workaround.  See gh-91126(2) for full
               details.

          Added in version 3.10.

          Changed in version 3.11: If a field name is already included
          in the ‘__slots__’ of a base class, it will not be included in
          the generated ‘__slots__’ to prevent *note overriding them:
          2120.  Therefore, do not use ‘__slots__’ to retrieve the field
          names of a dataclass.  Use *note fields(): 1857. instead.  To
          be able to determine inherited slots, base class ‘__slots__’
          may be any iterable, but 'not' an iterator.

        - 'weakref_slot': If true (the default is ‘False’), add a slot
          named “__weakref__”, which is required to make an instance
          *note weakref-able: 102b.  It is an error to specify
          ‘weakref_slot=True’ without also specifying ‘slots=True’.

          Added in version 3.11.

     ‘field’s may optionally specify a default value, using normal
     Python syntax:

          @dataclass
          class C:
              a: int       # 'a' has no default value
              b: int = 0   # assign a default value for 'b'

     In this example, both ‘a’ and ‘b’ will be included in the added
     *note __init__(): 6b3. method, which will be defined as:

          def __init__(self, a: int, b: int = 0):

     *note TypeError: 2c3. will be raised if a field without a default
     value follows a field with a default value.  This is true whether
     this occurs in a single class, or as a result of class inheritance.

 -- Function: dataclasses.field (*, default=MISSING,
          default_factory=MISSING, init=True, repr=True, hash=None,
          compare=True, metadata=None, kw_only=MISSING)

     For common and simple use cases, no other functionality is
     required.  There are, however, some dataclass features that require
     additional per-field information.  To satisfy this need for
     additional information, you can replace the default field value
     with a call to the provided ‘field()’ function.  For example:

          @dataclass
          class C:
              mylist: list[int] = field(default_factory=list)

          c = C()
          c.mylist += [1, 2, 3]

     As shown above, the *note MISSING: 4667. value is a sentinel object
     used to detect if some parameters are provided by the user.  This
     sentinel is used because ‘None’ is a valid value for some
     parameters with a distinct meaning.  No code should directly use
     the ‘MISSING’ value.

     The parameters to ‘field()’ are:

        - 'default': If provided, this will be the default value for
          this field.  This is needed because the ‘field()’ call itself
          replaces the normal position of the default value.

        - 'default_factory': If provided, it must be a zero-argument
          callable that will be called when a default value is needed
          for this field.  Among other purposes, this can be used to
          specify fields with mutable default values, as discussed
          below.  It is an error to specify both 'default' and
          'default_factory'.

        - 'init': If true (the default), this field is included as a
          parameter to the generated *note __init__(): 6b3. method.

        - 'repr': If true (the default), this field is included in the
          string returned by the generated *note __repr__(): 61f.
          method.

        - 'hash': This can be a bool or ‘None’.  If true, this field is
          included in the generated *note __hash__(): b14. method.  If
          false, this field is excluded from the generated ‘__hash__()’.
          If ‘None’ (the default), use the value of 'compare': this
          would normally be the expected behavior, since a field should
          be included in the hash if it’s used for comparisons.  Setting
          this value to anything other than ‘None’ is discouraged.

          One possible reason to set ‘hash=False’ but ‘compare=True’
          would be if a field is expensive to compute a hash value for,
          that field is needed for equality testing, and there are other
          fields that contribute to the type’s hash value.  Even if a
          field is excluded from the hash, it will still be used for
          comparisons.

        - 'compare': If true (the default), this field is included in
          the generated equality and comparison methods (*note __eq__():
          b13, *note __gt__(): 1355, et al.).

        - 'metadata': This can be a mapping or ‘None’.  ‘None’ is
          treated as an empty dict.  This value is wrapped in *note
          MappingProxyType(): 470. to make it read-only, and exposed on
          the *note Field: 240d. object.  It is not used at all by Data
          Classes, and is provided as a third-party extension mechanism.
          Multiple third-parties can each have their own key, to use as
          a namespace in the metadata.

        - 'kw_only': If true, this field will be marked as keyword-only.
          This is used when the generated *note __init__(): 6b3.
          method’s parameters are computed.

          Keyword-only fields are also not included in ‘__match_args__’.

          Added in version 3.10.

     If the default value of a field is specified by a call to
     ‘field()’, then the class attribute for this field will be replaced
     by the specified 'default' value.  If 'default' is not provided,
     then the class attribute will be deleted.  The intent is that after
     the *note @dataclass: 1cb. decorator runs, the class attributes
     will all contain the default values for the fields, just as if the
     default value itself were specified.  For example, after:

          @dataclass
          class C:
              x: int
              y: int = field(repr=False)
              z: int = field(repr=False, default=10)
              t: int = 20

     The class attribute ‘C.z’ will be ‘10’, the class attribute ‘C.t’
     will be ‘20’, and the class attributes ‘C.x’ and ‘C.y’ will not be
     set.

 -- Class: dataclasses.Field

     ‘Field’ objects describe each defined field.  These objects are
     created internally, and are returned by the *note fields(): 1857.
     module-level method (see below).  Users should never instantiate a
     ‘Field’ object directly.  Its documented attributes are:

        - ‘name’: The name of the field.

        - ‘type’: The type of the field.

        - ‘default’, ‘default_factory’, ‘init’, ‘repr’, ‘hash’,
          ‘compare’, ‘metadata’, and ‘kw_only’ have the identical
          meaning and values as they do in the *note field(): 1bb1.
          function.

     Other attributes may exist, but they are private and must not be
     inspected or relied on.

 -- Class: dataclasses.InitVar

     ‘InitVar[T]’ type annotations describe variables that are *note
     init-only: 4668.  Fields annotated with ‘InitVar’ are considered
     pseudo-fields, and thus are neither returned by the *note fields():
     1857. function nor used in any way except adding them as parameters
     to *note __init__(): 6b3. and an optional *note __post_init__():
     4669.

 -- Function: dataclasses.fields (class_or_instance)

     Returns a tuple of *note Field: 240d. objects that define the
     fields for this dataclass.  Accepts either a dataclass, or an
     instance of a dataclass.  Raises *note TypeError: 2c3. if not
     passed a dataclass or instance of one.  Does not return
     pseudo-fields which are ‘ClassVar’ or ‘InitVar’.

 -- Function: dataclasses.asdict (obj, *, dict_factory=dict)

     Converts the dataclass 'obj' to a dict (by using the factory
     function 'dict_factory').  Each dataclass is converted to a dict of
     its fields, as ‘name: value’ pairs.  dataclasses, dicts, lists, and
     tuples are recursed into.  Other objects are copied with *note
     copy.deepcopy(): b8a.

     Example of using ‘asdict()’ on nested dataclasses:

          @dataclass
          class Point:
               x: int
               y: int

          @dataclass
          class C:
               mylist: list[Point]

          p = Point(10, 20)
          assert asdict(p) == {'x': 10, 'y': 20}

          c = C([Point(0, 0), Point(10, 4)])
          assert asdict(c) == {'mylist': [{'x': 0, 'y': 0}, {'x': 10, 'y': 4}]}

     To create a shallow copy, the following workaround may be used:

          {field.name: getattr(obj, field.name) for field in fields(obj)}

     ‘asdict()’ raises *note TypeError: 2c3. if 'obj' is not a dataclass
     instance.

 -- Function: dataclasses.astuple (obj, *, tuple_factory=tuple)

     Converts the dataclass 'obj' to a tuple (by using the factory
     function 'tuple_factory').  Each dataclass is converted to a tuple
     of its field values.  dataclasses, dicts, lists, and tuples are
     recursed into.  Other objects are copied with *note
     copy.deepcopy(): b8a.

     Continuing from the previous example:

          assert astuple(p) == (10, 20)
          assert astuple(c) == ([(0, 0), (10, 4)],)

     To create a shallow copy, the following workaround may be used:

          tuple(getattr(obj, field.name) for field in dataclasses.fields(obj))

     ‘astuple()’ raises *note TypeError: 2c3. if 'obj' is not a
     dataclass instance.

 -- Function: dataclasses.make_dataclass (cls_name, fields, *, bases=(),
          namespace=None, init=True, repr=True, eq=True, order=False,
          unsafe_hash=False, frozen=False, match_args=True,
          kw_only=False, slots=False, weakref_slot=False, module=None)

     Creates a new dataclass with name 'cls_name', fields as defined in
     'fields', base classes as given in 'bases', and initialized with a
     namespace as given in 'namespace'.  'fields' is an iterable whose
     elements are each either ‘name’, ‘(name, type)’, or ‘(name, type,
     Field)’.  If just ‘name’ is supplied, *note typing.Any: 6af. is
     used for ‘type’.  The values of 'init', 'repr', 'eq', 'order',
     'unsafe_hash', 'frozen', 'match_args', 'kw_only', 'slots', and
     'weakref_slot' have the same meaning as they do in *note
     @dataclass: 1cb.

     If 'module' is defined, the ‘__module__’ attribute of the dataclass
     is set to that value.  By default, it is set to the module name of
     the caller.

     This function is not strictly required, because any Python
     mechanism for creating a new class with ‘__annotations__’ can then
     apply the *note @dataclass: 1cb. function to convert that class to
     a dataclass.  This function is provided as a convenience.  For
     example:

          C = make_dataclass('C',
                             [('x', int),
                               'y',
                              ('z', int, field(default=5))],
                             namespace={'add_one': lambda self: self.x + 1})

     Is equivalent to:

          @dataclass
          class C:
              x: int
              y: 'typing.Any'
              z: int = 5

              def add_one(self):
                  return self.x + 1

 -- Function: dataclasses.replace (obj, /, **changes)

     Creates a new object of the same type as 'obj', replacing fields
     with values from 'changes'.  If 'obj' is not a Data Class, raises
     *note TypeError: 2c3.  If keys in 'changes' are not field names of
     the given dataclass, raises ‘TypeError’.

     The newly returned object is created by calling the *note
     __init__(): 6b3. method of the dataclass.  This ensures that *note
     __post_init__(): 4669, if present, is also called.

     Init-only variables without default values, if any exist, must be
     specified on the call to ‘replace()’ so that they can be passed to
     ‘__init__()’ and *note __post_init__(): 4669.

     It is an error for 'changes' to contain any fields that are defined
     as having ‘init=False’.  A *note ValueError: 202. will be raised in
     this case.

     Be forewarned about how ‘init=False’ fields work during a call to
     ‘replace()’.  They are not copied from the source object, but
     rather are initialized in *note __post_init__(): 4669, if they’re
     initialized at all.  It is expected that ‘init=False’ fields will
     be rarely and judiciously used.  If they are used, it might be wise
     to have alternate class constructors, or perhaps a custom
     ‘replace()’ (or similarly named) method which handles instance
     copying.

     Dataclass instances are also supported by generic function *note
     copy.replace(): 151.

 -- Function: dataclasses.is_dataclass (obj)

     Return ‘True’ if its parameter is a dataclass (including subclasses
     of a dataclass) or an instance of one, otherwise return ‘False’.

     If you need to know if a class is an instance of a dataclass (and
     not a dataclass itself), then add a further check for ‘not
     isinstance(obj, type)’:

          def is_dataclass_instance(obj):
              return is_dataclass(obj) and not isinstance(obj, type)

 -- Data: dataclasses.MISSING

     A sentinel value signifying a missing default or default_factory.

 -- Data: dataclasses.KW_ONLY

     A sentinel value used as a type annotation.  Any fields after a
     pseudo-field with the type of ‘KW_ONLY’ are marked as keyword-only
     fields.  Note that a pseudo-field of type ‘KW_ONLY’ is otherwise
     completely ignored.  This includes the name of such a field.  By
     convention, a name of ‘_’ is used for a ‘KW_ONLY’ field.
     Keyword-only fields signify *note __init__(): 6b3. parameters that
     must be specified as keywords when the class is instantiated.

     In this example, the fields ‘y’ and ‘z’ will be marked as
     keyword-only fields:

          @dataclass
          class Point:
              x: float
              _: KW_ONLY
              y: float
              z: float

          p = Point(0, y=1.5, z=2.0)

     In a single dataclass, it is an error to specify more than one
     field whose type is ‘KW_ONLY’.

     Added in version 3.10.

 -- Exception: dataclasses.FrozenInstanceError

     Raised when an implicitly defined *note __setattr__(): 20de. or
     *note __delattr__(): 20df. is called on a dataclass which was
     defined with ‘frozen=True’.  It is a subclass of *note
     AttributeError: 34e.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/90562

   (2) https://github.com/python/cpython/issues/91126


File: python.info,  Node: Post-init processing,  Next: Class variables,  Prev: Module contents<5>,  Up: dataclasses — Data Classes

5.29.7.2 Post-init processing
.............................

 -- Function: dataclasses.__post_init__ ()

     When defined on the class, it will be called by the generated *note
     __init__(): 6b3, normally as ‘self.__post_init__()’.  However, if
     any ‘InitVar’ fields are defined, they will also be passed to
     ‘__post_init__()’ in the order they were defined in the class.  If
     no ‘__init__()’ method is generated, then ‘__post_init__()’ will
     not automatically be called.

     Among other uses, this allows for initializing field values that
     depend on one or more other fields.  For example:

          @dataclass
          class C:
              a: float
              b: float
              c: float = field(init=False)

              def __post_init__(self):
                  self.c = self.a + self.b

The *note __init__(): 6b3. method generated by *note @dataclass: 1cb.
does not call base class ‘__init__()’ methods.  If the base class has an
‘__init__()’ method that has to be called, it is common to call this
method in a *note __post_init__(): 4669. method:

     class Rectangle:
         def __init__(self, height, width):
             self.height = height
             self.width = width

     @dataclass
     class Square(Rectangle):
         side: float

         def __post_init__(self):
             super().__init__(self.side, self.side)

Note, however, that in general the dataclass-generated ‘__init__()’
methods don’t need to be called, since the derived dataclass will take
care of initializing all fields of any base class that is a dataclass
itself.

See the section below on init-only variables for ways to pass parameters
to ‘__post_init__()’.  Also see the warning about how *note replace():
1809. handles ‘init=False’ fields.


File: python.info,  Node: Class variables,  Next: Init-only variables,  Prev: Post-init processing,  Up: dataclasses — Data Classes

5.29.7.3 Class variables
........................

One of the few places where *note @dataclass: 1cb. actually inspects the
type of a field is to determine if a field is a class variable as
defined in PEP 526(1).  It does this by checking if the type of the
field is *note typing.ClassVar: 266.  If a field is a ‘ClassVar’, it is
excluded from consideration as a field and is ignored by the dataclass
mechanisms.  Such ‘ClassVar’ pseudo-fields are not returned by the
module-level *note fields(): 1857. function.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0526/


File: python.info,  Node: Init-only variables,  Next: Frozen instances,  Prev: Class variables,  Up: dataclasses — Data Classes

5.29.7.4 Init-only variables
............................

Another place where *note @dataclass: 1cb. inspects a type annotation is
to determine if a field is an init-only variable.  It does this by
seeing if the type of a field is of type *note InitVar: 1959.  If a
field is an ‘InitVar’, it is considered a pseudo-field called an
init-only field.  As it is not a true field, it is not returned by the
module-level *note fields(): 1857. function.  Init-only fields are added
as parameters to the generated *note __init__(): 6b3. method, and are
passed to the optional *note __post_init__(): 4669. method.  They are
not otherwise used by dataclasses.

For example, suppose a field will be initialized from a database, if a
value is not provided when creating the class:

     @dataclass
     class C:
         i: int
         j: int | None = None
         database: InitVar[DatabaseType | None] = None

         def __post_init__(self, database):
             if self.j is None and database is not None:
                 self.j = database.lookup('j')

     c = C(10, database=my_database)

In this case, *note fields(): 1857. will return *note Field: 240d.
objects for ‘i’ and ‘j’, but not for ‘database’.


File: python.info,  Node: Frozen instances,  Next: Inheritance<2>,  Prev: Init-only variables,  Up: dataclasses — Data Classes

5.29.7.5 Frozen instances
.........................

It is not possible to create truly immutable Python objects.  However,
by passing ‘frozen=True’ to the *note @dataclass: 1cb. decorator you can
emulate immutability.  In that case, dataclasses will add *note
__setattr__(): 20de. and *note __delattr__(): 20df. methods to the
class.  These methods will raise a *note FrozenInstanceError: 466a. when
invoked.

There is a tiny performance penalty when using ‘frozen=True’: *note
__init__(): 6b3. cannot use simple assignment to initialize fields, and
must use ‘object.__setattr__()’.


File: python.info,  Node: Inheritance<2>,  Next: Re-ordering of keyword-only parameters in __init__,  Prev: Frozen instances,  Up: dataclasses — Data Classes

5.29.7.6 Inheritance
....................

When the dataclass is being created by the *note @dataclass: 1cb.
decorator, it looks through all of the class’s base classes in reverse
MRO (that is, starting at *note object: a9b.) and, for each dataclass
that it finds, adds the fields from that base class to an ordered
mapping of fields.  After all of the base class fields are added, it
adds its own fields to the ordered mapping.  All of the generated
methods will use this combined, calculated ordered mapping of fields.
Because the fields are in insertion order, derived classes override base
classes.  An example:

     @dataclass
     class Base:
         x: Any = 15.0
         y: int = 0

     @dataclass
     class C(Base):
         z: int = 10
         x: int = 15

The final list of fields is, in order, ‘x’, ‘y’, ‘z’.  The final type of
‘x’ is *note int: 257, as specified in class ‘C’.

The generated *note __init__(): 6b3. method for ‘C’ will look like:

     def __init__(self, x: int = 15, y: int = 0, z: int = 10):


File: python.info,  Node: Re-ordering of keyword-only parameters in __init__,  Next: Default factory functions,  Prev: Inheritance<2>,  Up: dataclasses — Data Classes

5.29.7.7 Re-ordering of keyword-only parameters in ‘__init__()’
...............................................................

After the parameters needed for *note __init__(): 6b3. are computed, any
keyword-only parameters are moved to come after all regular
(non-keyword-only) parameters.  This is a requirement of how
keyword-only parameters are implemented in Python: they must come after
non-keyword-only parameters.

In this example, ‘Base.y’, ‘Base.w’, and ‘D.t’ are keyword-only fields,
and ‘Base.x’ and ‘D.z’ are regular fields:

     @dataclass
     class Base:
         x: Any = 15.0
         _: KW_ONLY
         y: int = 0
         w: int = 1

     @dataclass
     class D(Base):
         z: int = 10
         t: int = field(kw_only=True, default=0)

The generated ‘__init__()’ method for ‘D’ will look like:

     def __init__(self, x: Any = 15.0, z: int = 10, *, y: int = 0, w: int = 1, t: int = 0):

Note that the parameters have been re-ordered from how they appear in
the list of fields: parameters derived from regular fields are followed
by parameters derived from keyword-only fields.

The relative ordering of keyword-only parameters is maintained in the
re-ordered ‘__init__()’ parameter list.


File: python.info,  Node: Default factory functions,  Next: Mutable default values,  Prev: Re-ordering of keyword-only parameters in __init__,  Up: dataclasses — Data Classes

5.29.7.8 Default factory functions
..................................

If a *note field(): 1bb1. specifies a 'default_factory', it is called
with zero arguments when a default value for the field is needed.  For
example, to create a new instance of a list, use:

     mylist: list = field(default_factory=list)

If a field is excluded from *note __init__(): 6b3. (using ‘init=False’)
and the field also specifies 'default_factory', then the default factory
function will always be called from the generated ‘__init__()’ function.
This happens because there is no other way to give the field an initial
value.


File: python.info,  Node: Mutable default values,  Next: Descriptor-typed fields,  Prev: Default factory functions,  Up: dataclasses — Data Classes

5.29.7.9 Mutable default values
...............................

Python stores default member variable values in class attributes.
Consider this example, not using dataclasses:

     class C:
         x = []
         def add(self, element):
             self.x.append(element)

     o1 = C()
     o2 = C()
     o1.add(1)
     o2.add(2)
     assert o1.x == [1, 2]
     assert o1.x is o2.x

Note that the two instances of class ‘C’ share the same class variable
‘x’, as expected.

Using dataclasses, 'if' this code was valid:

     @dataclass
     class D:
         x: list = []      # This code raises ValueError
         def add(self, element):
             self.x.append(element)

it would generate code similar to:

     class D:
         x = []
         def __init__(self, x=x):
             self.x = x
         def add(self, element):
             self.x.append(element)

     assert D().x is D().x

This has the same issue as the original example using class ‘C’.  That
is, two instances of class ‘D’ that do not specify a value for ‘x’ when
creating a class instance will share the same copy of ‘x’.  Because
dataclasses just use normal Python class creation they also share this
behavior.  There is no general way for Data Classes to detect this
condition.  Instead, the *note @dataclass: 1cb. decorator will raise a
*note ValueError: 202. if it detects an unhashable default parameter.
The assumption is that if a value is unhashable, it is mutable.  This is
a partial solution, but it does protect against many common errors.

Using default factory functions is a way to create new instances of
mutable types as default values for fields:

     @dataclass
     class D:
         x: list = field(default_factory=list)

     assert D().x is not D().x

Changed in version 3.11: Instead of looking for and disallowing objects
of type *note list: 614, *note dict: 256, or *note set: 5dc, unhashable
objects are now not allowed as default values.  Unhashability is used to
approximate mutability.


File: python.info,  Node: Descriptor-typed fields,  Prev: Mutable default values,  Up: dataclasses — Data Classes

5.29.7.10 Descriptor-typed fields
.................................

Fields that are assigned *note descriptor objects: c70. as their default
value have the following special behaviors:

   * The value for the field passed to the dataclass’s *note __init__():
     6b3. method is passed to the descriptor’s *note __set__(): 211b.
     method rather than overwriting the descriptor object.

   * Similarly, when getting or setting the field, the descriptor’s
     *note __get__(): 1537. or ‘__set__()’ method is called rather than
     returning or overwriting the descriptor object.

   * To determine whether a field contains a default value, *note
     @dataclass: 1cb. will call the descriptor’s ‘__get__()’ method
     using its class access form: ‘descriptor.__get__(obj=None,
     type=cls)’.  If the descriptor returns a value in this case, it
     will be used as the field’s default.  On the other hand, if the
     descriptor raises *note AttributeError: 34e. in this situation, no
     default value will be provided for the field.

     class IntConversionDescriptor:
         def __init__(self, *, default):
             self._default = default

         def __set_name__(self, owner, name):
             self._name = "_" + name

         def __get__(self, obj, type):
             if obj is None:
                 return self._default

             return getattr(obj, self._name, self._default)

         def __set__(self, obj, value):
             setattr(obj, self._name, int(value))

     @dataclass
     class InventoryItem:
         quantity_on_hand: IntConversionDescriptor = IntConversionDescriptor(default=100)

     i = InventoryItem()
     print(i.quantity_on_hand)   # 100
     i.quantity_on_hand = 2.5    # calls __set__ with 2.5
     print(i.quantity_on_hand)   # 2

Note that if a field is annotated with a descriptor type, but is not
assigned a descriptor object as its default value, the field will act
like a normal field.


File: python.info,  Node: contextlib — Utilities for with-statement contexts,  Next: abc — Abstract Base Classes,  Prev: dataclasses — Data Classes,  Up: Python Runtime Services

5.29.8 ‘contextlib’ — Utilities for ‘with’-statement contexts
-------------------------------------------------------------

'Source code:' Lib/contextlib.py(1)

__________________________________________________________________

This module provides utilities for common tasks involving the *note
with: 5d5. statement.  For more information see also *note Context
Manager Types: 2171. and *note With Statement Context Managers: 20e4.

* Menu:

* Utilities::
* Examples and Recipes: Examples and Recipes<3>.
* Single use, reusable and reentrant context managers: Single use reusable and reentrant context managers.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/contextlib.py


File: python.info,  Node: Utilities,  Next: Examples and Recipes<3>,  Up: contextlib — Utilities for with-statement contexts

5.29.8.1 Utilities
..................

Functions and classes provided:

 -- Class: contextlib.AbstractContextManager

     An *note abstract base class: 11fa. for classes that implement
     *note __enter__(): 5cb. and *note __exit__(): 1349.  A default
     implementation for ‘__enter__()’ is provided which returns ‘self’
     while ‘__exit__()’ is an abstract method which by default returns
     ‘None’.  See also the definition of *note Context Manager Types:
     2171.

     Added in version 3.6.

 -- Class: contextlib.AbstractAsyncContextManager

     An *note abstract base class: 11fa. for classes that implement
     *note __aenter__(): 2181. and *note __aexit__(): 1734.  A default
     implementation for ‘__aenter__()’ is provided which returns ‘self’
     while ‘__aexit__()’ is an abstract method which by default returns
     ‘None’.  See also the definition of *note Asynchronous Context
     Managers: 5ff.

     Added in version 3.7.

 -- Function: @contextlib.contextmanager

     This function is a *note decorator: 734. that can be used to define
     a factory function for *note with: 5d5. statement context managers,
     without needing to create a class or separate *note __enter__():
     5cb. and *note __exit__(): 1349. methods.

     While many objects natively support use in with statements,
     sometimes a resource needs to be managed that isn’t a context
     manager in its own right, and doesn’t implement a ‘close()’ method
     for use with ‘contextlib.closing’.

     An abstract example would be the following to ensure correct
     resource management:

          from contextlib import contextmanager

          @contextmanager
          def managed_resource(*args, **kwds):
              # Code to acquire resource, e.g.:
              resource = acquire_resource(*args, **kwds)
              try:
                  yield resource
              finally:
                  # Code to release resource, e.g.:
                  release_resource(resource)

     The function can then be used like this:

          >>> with managed_resource(timeout=3600) as resource:
          ...     # Resource is released at the end of this block,
          ...     # even if code in the block raises an exception

     The function being decorated must return a *note generator:
     109f.-iterator when called.  This iterator must yield exactly one
     value, which will be bound to the targets in the *note with: 5d5.
     statement’s ‘as’ clause, if any.

     At the point where the generator yields, the block nested in the
     *note with: 5d5. statement is executed.  The generator is then
     resumed after the block is exited.  If an unhandled exception
     occurs in the block, it is reraised inside the generator at the
     point where the yield occurred.  Thus, you can use a *note try:
     6ec.…*note except: 18b.…*note finally: 9d5. statement to trap the
     error (if any), or ensure that some cleanup takes place.  If an
     exception is trapped merely in order to log it or to perform some
     action (rather than to suppress it entirely), the generator must
     reraise that exception.  Otherwise the generator context manager
     will indicate to the ‘with’ statement that the exception has been
     handled, and execution will resume with the statement immediately
     following the ‘with’ statement.

     ‘contextmanager()’ uses *note ContextDecorator: 1246. so the
     context managers it creates can be used as decorators as well as in
     *note with: 5d5. statements.  When used as a decorator, a new
     generator instance is implicitly created on each function call
     (this allows the otherwise “one-shot” context managers created by
     ‘contextmanager()’ to meet the requirement that context managers
     support multiple invocations in order to be used as decorators).

     Changed in version 3.2: Use of *note ContextDecorator: 1246.

 -- Function: @contextlib.asynccontextmanager

     Similar to *note contextmanager(): 1247, but creates an *note
     asynchronous context manager: 5ff.

     This function is a *note decorator: 734. that can be used to define
     a factory function for *note async with: 5d8. statement
     asynchronous context managers, without needing to create a class or
     separate *note __aenter__(): 2181. and *note __aexit__(): 1734.
     methods.  It must be applied to an *note asynchronous generator:
     21f2. function.

     A simple example:

          from contextlib import asynccontextmanager

          @asynccontextmanager
          async def get_connection():
              conn = await acquire_db_connection()
              try:
                  yield conn
              finally:
                  await release_db_connection(conn)

          async def get_all_users():
              async with get_connection() as conn:
                  return conn.query('SELECT ...')

     Added in version 3.7.

     Context managers defined with ‘asynccontextmanager()’ can be used
     either as decorators or with *note async with: 5d8. statements:

          import time
          from contextlib import asynccontextmanager

          @asynccontextmanager
          async def timeit():
              now = time.monotonic()
              try:
                  yield
              finally:
                  print(f'it took {time.monotonic() - now}s to run')

          @timeit()
          async def main():
              # ... async code ...

     When used as a decorator, a new generator instance is implicitly
     created on each function call.  This allows the otherwise
     “one-shot” context managers created by ‘asynccontextmanager()’ to
     meet the requirement that context managers support multiple
     invocations in order to be used as decorators.

     Changed in version 3.10: Async context managers created with
     ‘asynccontextmanager()’ can be used as decorators.

 -- Function: contextlib.closing (thing)

     Return a context manager that closes 'thing' upon completion of the
     block.  This is basically equivalent to:

          from contextlib import contextmanager

          @contextmanager
          def closing(thing):
              try:
                  yield thing
              finally:
                  thing.close()

     And lets you write code like this:

          from contextlib import closing
          from urllib.request import urlopen

          with closing(urlopen('https://www.python.org')) as page:
              for line in page:
                  print(line)

     without needing to explicitly close ‘page’.  Even if an error
     occurs, ‘page.close()’ will be called when the *note with: 5d5.
     block is exited.

          Note: Most types managing resources support the *note context
          manager: 5d7. protocol, which closes 'thing' on leaving the
          *note with: 5d5. statement.  As such, ‘closing()’ is most
          useful for third party types that don’t support context
          managers.  This example is purely for illustration purposes,
          as *note urlopen(): 293. would normally be used in a context
          manager.

 -- Function: contextlib.aclosing (thing)

     Return an async context manager that calls the ‘aclose()’ method of
     'thing' upon completion of the block.  This is basically equivalent
     to:

          from contextlib import asynccontextmanager

          @asynccontextmanager
          async def aclosing(thing):
              try:
                  yield thing
              finally:
                  await thing.aclose()

     Significantly, ‘aclosing()’ supports deterministic cleanup of async
     generators when they happen to exit early by *note break: abe. or
     an exception.  For example:

          from contextlib import aclosing

          async with aclosing(my_generator()) as values:
              async for value in values:
                  if value == 42:
                      break

     This pattern ensures that the generator’s async exit code is
     executed in the same context as its iterations (so that exceptions
     and context variables work as expected, and the exit code isn’t run
     after the lifetime of some task it depends on).

     Added in version 3.10.

 -- Function: contextlib.nullcontext (enter_result=None)

     Return a context manager that returns 'enter_result' from *note
     __enter__(): 5cb, but otherwise does nothing.  It is intended to be
     used as a stand-in for an optional context manager, for example:

          def myfunction(arg, ignore_exceptions=False):
              if ignore_exceptions:
                  # Use suppress to ignore all exceptions.
                  cm = contextlib.suppress(Exception)
              else:
                  # Do not ignore any exceptions, cm has no effect.
                  cm = contextlib.nullcontext()
              with cm:
                  # Do something

     An example using 'enter_result':

          def process_file(file_or_path):
              if isinstance(file_or_path, str):
                  # If string, open file
                  cm = open(file_or_path)
              else:
                  # Caller is responsible for closing file
                  cm = nullcontext(file_or_path)

              with cm as file:
                  # Perform processing on the file

     It can also be used as a stand-in for *note asynchronous context
     managers: 5ff.:

          async def send_http(session=None):
              if not session:
                  # If no http session, create it with aiohttp
                  cm = aiohttp.ClientSession()
              else:
                  # Caller is responsible for closing the session
                  cm = nullcontext(session)

              async with cm as session:
                  # Send http requests with session

     Added in version 3.7.

     Changed in version 3.10: *note asynchronous context manager: 5da.
     support was added.

 -- Function: contextlib.suppress (*exceptions)

     Return a context manager that suppresses any of the specified
     exceptions if they occur in the body of a ‘with’ statement and then
     resumes execution with the first statement following the end of the
     ‘with’ statement.

     As with any other mechanism that completely suppresses exceptions,
     this context manager should be used only to cover very specific
     errors where silently continuing with program execution is known to
     be the right thing to do.

     For example:

          from contextlib import suppress

          with suppress(FileNotFoundError):
              os.remove('somefile.tmp')

          with suppress(FileNotFoundError):
              os.remove('someotherfile.tmp')

     This code is equivalent to:

          try:
              os.remove('somefile.tmp')
          except FileNotFoundError:
              pass

          try:
              os.remove('someotherfile.tmp')
          except FileNotFoundError:
              pass

     This context manager is *note reentrant: 467c.

     If the code within the ‘with’ block raises a *note
     BaseExceptionGroup: 25f, suppressed exceptions are removed from the
     group.  Any exceptions of the group which are not suppressed are
     re-raised in a new group which is created using the original
     group’s *note derive(): 17d0. method.

     Added in version 3.4.

     Changed in version 3.12: ‘suppress’ now supports suppressing
     exceptions raised as part of a *note BaseExceptionGroup: 25f.

 -- Function: contextlib.redirect_stdout (new_target)

     Context manager for temporarily redirecting *note sys.stdout: aec.
     to another file or file-like object.

     This tool adds flexibility to existing functions or classes whose
     output is hardwired to stdout.

     For example, the output of *note help(): 8e0. normally is sent to
     'sys.stdout'.  You can capture that output in a string by
     redirecting the output to an *note io.StringIO: f5e. object.  The
     replacement stream is returned from the *note __enter__(): 5cb.
     method and so is available as the target of the *note with: 5d5.
     statement:

          with redirect_stdout(io.StringIO()) as f:
              help(pow)
          s = f.getvalue()

     To send the output of *note help(): 8e0. to a file on disk,
     redirect the output to a regular file:

          with open('help.txt', 'w') as f:
              with redirect_stdout(f):
                  help(pow)

     To send the output of *note help(): 8e0. to 'sys.stderr':

          with redirect_stdout(sys.stderr):
              help(pow)

     Note that the global side effect on *note sys.stdout: aec. means
     that this context manager is not suitable for use in library code
     and most threaded applications.  It also has no effect on the
     output of subprocesses.  However, it is still a useful approach for
     many utility scripts.

     This context manager is *note reentrant: 467c.

     Added in version 3.4.

 -- Function: contextlib.redirect_stderr (new_target)

     Similar to *note redirect_stdout(): e18. but redirecting *note
     sys.stderr: 943. to another file or file-like object.

     This context manager is *note reentrant: 467c.

     Added in version 3.5.

 -- Function: contextlib.chdir (path)

     Non parallel-safe context manager to change the current working
     directory.  As this changes a global state, the working directory,
     it is not suitable for use in most threaded or async contexts.  It
     is also not suitable for most non-linear code execution, like
     generators, where the program execution is temporarily relinquished
     – unless explicitly desired, you should not yield when this context
     manager is active.

     This is a simple wrapper around *note chdir(): 610, it changes the
     current working directory upon entering and restores the old one on
     exit.

     This context manager is *note reentrant: 467c.

     Added in version 3.11.

 -- Class: contextlib.ContextDecorator

     A base class that enables a context manager to also be used as a
     decorator.

     Context managers inheriting from ‘ContextDecorator’ have to
     implement *note __enter__(): 5cb. and *note __exit__(): 1349. as
     normal.  ‘__exit__’ retains its optional exception handling even
     when used as a decorator.

     ‘ContextDecorator’ is used by *note contextmanager(): 1247, so you
     get this functionality automatically.

     Example of ‘ContextDecorator’:

          from contextlib import ContextDecorator

          class mycontext(ContextDecorator):
              def __enter__(self):
                  print('Starting')
                  return self

              def __exit__(self, *exc):
                  print('Finishing')
                  return False

     The class can then be used like this:

          >>> @mycontext()
          ... def function():
          ...     print('The bit in the middle')
          ...
          >>> function()
          Starting
          The bit in the middle
          Finishing

          >>> with mycontext():
          ...     print('The bit in the middle')
          ...
          Starting
          The bit in the middle
          Finishing

     This change is just syntactic sugar for any construct of the
     following form:

          def f():
              with cm():
                  # Do stuff

     ‘ContextDecorator’ lets you instead write:

          @cm()
          def f():
              # Do stuff

     It makes it clear that the ‘cm’ applies to the whole function,
     rather than just a piece of it (and saving an indentation level is
     nice, too).

     Existing context managers that already have a base class can be
     extended by using ‘ContextDecorator’ as a mixin class:

          from contextlib import ContextDecorator

          class mycontext(ContextBaseClass, ContextDecorator):
              def __enter__(self):
                  return self

              def __exit__(self, *exc):
                  return False

          Note: As the decorated function must be able to be called
          multiple times, the underlying context manager must support
          use in multiple *note with: 5d5. statements.  If this is not
          the case, then the original construct with the explicit ‘with’
          statement inside the function should be used.

     Added in version 3.2.

 -- Class: contextlib.AsyncContextDecorator

     Similar to *note ContextDecorator: 1246. but only for asynchronous
     functions.

     Example of ‘AsyncContextDecorator’:

          from asyncio import run
          from contextlib import AsyncContextDecorator

          class mycontext(AsyncContextDecorator):
              async def __aenter__(self):
                  print('Starting')
                  return self

              async def __aexit__(self, *exc):
                  print('Finishing')
                  return False

     The class can then be used like this:

          >>> @mycontext()
          ... async def function():
          ...     print('The bit in the middle')
          ...
          >>> run(function())
          Starting
          The bit in the middle
          Finishing

          >>> async def function():
          ...    async with mycontext():
          ...         print('The bit in the middle')
          ...
          >>> run(function())
          Starting
          The bit in the middle
          Finishing

     Added in version 3.10.

 -- Class: contextlib.ExitStack

     A context manager that is designed to make it easy to
     programmatically combine other context managers and cleanup
     functions, especially those that are optional or otherwise driven
     by input data.

     For example, a set of files may easily be handled in a single with
     statement as follows:

          with ExitStack() as stack:
              files = [stack.enter_context(open(fname)) for fname in filenames]
              # All opened files will automatically be closed at the end of
              # the with statement, even if attempts to open files later
              # in the list raise an exception

     The *note __enter__(): 5cb. method returns the ‘ExitStack’
     instance, and performs no additional operations.

     Each instance maintains a stack of registered callbacks that are
     called in reverse order when the instance is closed (either
     explicitly or implicitly at the end of a *note with: 5d5.
     statement).  Note that callbacks are 'not' invoked implicitly when
     the context stack instance is garbage collected.

     This stack model is used so that context managers that acquire
     their resources in their ‘__init__’ method (such as file objects)
     can be handled correctly.

     Since registered callbacks are invoked in the reverse order of
     registration, this ends up behaving as if multiple nested *note
     with: 5d5. statements had been used with the registered set of
     callbacks.  This even extends to exception handling - if an inner
     callback suppresses or replaces an exception, then outer callbacks
     will be passed arguments based on that updated state.

     This is a relatively low level API that takes care of the details
     of correctly unwinding the stack of exit callbacks.  It provides a
     suitable foundation for higher level context managers that
     manipulate the exit stack in application specific ways.

     Added in version 3.3.

      -- Method: enter_context (cm)

          Enters a new context manager and adds its *note __exit__():
          1349. method to the callback stack.  The return value is the
          result of the context manager’s own *note __enter__(): 5cb.
          method.

          These context managers may suppress exceptions just as they
          normally would if used directly as part of a *note with: 5d5.
          statement.

          Changed in version 3.11: Raises *note TypeError: 2c3. instead
          of *note AttributeError: 34e. if 'cm' is not a context
          manager.

      -- Method: push (exit)

          Adds a context manager’s *note __exit__(): 1349. method to the
          callback stack.

          As ‘__enter__’ is 'not' invoked, this method can be used to
          cover part of an *note __enter__(): 5cb. implementation with a
          context manager’s own *note __exit__(): 1349. method.

          If passed an object that is not a context manager, this method
          assumes it is a callback with the same signature as a context
          manager’s *note __exit__(): 1349. method and adds it directly
          to the callback stack.

          By returning true values, these callbacks can suppress
          exceptions the same way context manager *note __exit__():
          1349. methods can.

          The passed in object is returned from the function, allowing
          this method to be used as a function decorator.

      -- Method: callback (callback, /, *args, **kwds)

          Accepts an arbitrary callback function and arguments and adds
          it to the callback stack.

          Unlike the other methods, callbacks added this way cannot
          suppress exceptions (as they are never passed the exception
          details).

          The passed in callback is returned from the function, allowing
          this method to be used as a function decorator.

      -- Method: pop_all ()

          Transfers the callback stack to a fresh ‘ExitStack’ instance
          and returns it.  No callbacks are invoked by this operation -
          instead, they will now be invoked when the new stack is closed
          (either explicitly or implicitly at the end of a *note with:
          5d5. statement).

          For example, a group of files can be opened as an “all or
          nothing” operation as follows:

               with ExitStack() as stack:
                   files = [stack.enter_context(open(fname)) for fname in filenames]
                   # Hold onto the close method, but don't call it yet.
                   close_files = stack.pop_all().close
                   # If opening any file fails, all previously opened files will be
                   # closed automatically. If all files are opened successfully,
                   # they will remain open even after the with statement ends.
                   # close_files() can then be invoked explicitly to close them all.

      -- Method: close ()

          Immediately unwinds the callback stack, invoking callbacks in
          the reverse order of registration.  For any context managers
          and exit callbacks registered, the arguments passed in will
          indicate that no exception occurred.

 -- Class: contextlib.AsyncExitStack

     An *note asynchronous context manager: 5ff, similar to *note
     ExitStack: b41, that supports combining both synchronous and
     asynchronous context managers, as well as having coroutines for
     cleanup logic.

     The *note close(): 467f. method is not implemented; *note aclose():
     4680. must be used instead.

      -- Method: async enter_async_context (cm)

          Similar to *note ExitStack.enter_context(): 5d6. but expects
          an asynchronous context manager.

          Changed in version 3.11: Raises *note TypeError: 2c3. instead
          of *note AttributeError: 34e. if 'cm' is not an asynchronous
          context manager.

      -- Method: push_async_exit (exit)

          Similar to *note ExitStack.push(): 467d. but expects either an
          asynchronous context manager or a coroutine function.

      -- Method: push_async_callback (callback, /, *args, **kwds)

          Similar to *note ExitStack.callback(): a92. but expects a
          coroutine function.

      -- Method: async aclose ()

          Similar to *note ExitStack.close(): 467f. but properly handles
          awaitables.

     Continuing the example for *note asynccontextmanager(): b42.:

          async with AsyncExitStack() as stack:
              connections = [await stack.enter_async_context(get_connection())
                  for i in range(5)]
              # All opened connections will automatically be released at the end of
              # the async with statement, even if attempts to open a connection
              # later in the list raise an exception.

     Added in version 3.7.


File: python.info,  Node: Examples and Recipes<3>,  Next: Single use reusable and reentrant context managers,  Prev: Utilities,  Up: contextlib — Utilities for with-statement contexts

5.29.8.2 Examples and Recipes
.............................

This section describes some examples and recipes for making effective
use of the tools provided by ‘contextlib’.

* Menu:

* Supporting a variable number of context managers::
* Catching exceptions from __enter__ methods::
* Cleaning up in an __enter__ implementation::
* Replacing any use of try-finally and flag variables::
* Using a context manager as a function decorator::


File: python.info,  Node: Supporting a variable number of context managers,  Next: Catching exceptions from __enter__ methods,  Up: Examples and Recipes<3>

5.29.8.3 Supporting a variable number of context managers
.........................................................

The primary use case for *note ExitStack: b41. is the one given in the
class documentation: supporting a variable number of context managers
and other cleanup operations in a single *note with: 5d5. statement.
The variability may come from the number of context managers needed
being driven by user input (such as opening a user specified collection
of files), or from some of the context managers being optional:

     with ExitStack() as stack:
         for resource in resources:
             stack.enter_context(resource)
         if need_special_resource():
             special = acquire_special_resource()
             stack.callback(release_special_resource, special)
         # Perform operations that use the acquired resources

As shown, *note ExitStack: b41. also makes it quite easy to use *note
with: 5d5. statements to manage arbitrary resources that don’t natively
support the context management protocol.


File: python.info,  Node: Catching exceptions from __enter__ methods,  Next: Cleaning up in an __enter__ implementation,  Prev: Supporting a variable number of context managers,  Up: Examples and Recipes<3>

5.29.8.4 Catching exceptions from ‘__enter__’ methods
.....................................................

It is occasionally desirable to catch exceptions from an *note
__enter__(): 5cb. method implementation, 'without' inadvertently
catching exceptions from the *note with: 5d5. statement body or the
context manager’s *note __exit__(): 1349. method.  By using *note
ExitStack: b41. the steps in the context management protocol can be
separated slightly in order to allow this:

     stack = ExitStack()
     try:
         x = stack.enter_context(cm)
     except Exception:
         # handle __enter__ exception
     else:
         with stack:
             # Handle normal case

Actually needing to do this is likely to indicate that the underlying
API should be providing a direct resource management interface for use
with *note try: 6ec./*note except: 18b./*note finally: 9d5. statements,
but not all APIs are well designed in that regard.  When a context
manager is the only resource management API provided, then *note
ExitStack: b41. can make it easier to handle various situations that
can’t be handled directly in a *note with: 5d5. statement.


File: python.info,  Node: Cleaning up in an __enter__ implementation,  Next: Replacing any use of try-finally and flag variables,  Prev: Catching exceptions from __enter__ methods,  Up: Examples and Recipes<3>

5.29.8.5 Cleaning up in an ‘__enter__’ implementation
.....................................................

As noted in the documentation of *note ExitStack.push(): 467d, this
method can be useful in cleaning up an already allocated resource if
later steps in the *note __enter__(): 5cb. implementation fail.

Here’s an example of doing this for a context manager that accepts
resource acquisition and release functions, along with an optional
validation function, and maps them to the context management protocol:

     from contextlib import contextmanager, AbstractContextManager, ExitStack

     class ResourceManager(AbstractContextManager):

         def __init__(self, acquire_resource, release_resource, check_resource_ok=None):
             self.acquire_resource = acquire_resource
             self.release_resource = release_resource
             if check_resource_ok is None:
                 def check_resource_ok(resource):
                     return True
             self.check_resource_ok = check_resource_ok

         @contextmanager
         def _cleanup_on_error(self):
             with ExitStack() as stack:
                 stack.push(self)
                 yield
                 # The validation check passed and didn't raise an exception
                 # Accordingly, we want to keep the resource, and pass it
                 # back to our caller
                 stack.pop_all()

         def __enter__(self):
             resource = self.acquire_resource()
             with self._cleanup_on_error():
                 if not self.check_resource_ok(resource):
                     msg = "Failed validation for {!r}"
                     raise RuntimeError(msg.format(resource))
             return resource

         def __exit__(self, *exc_details):
             # We don't need to duplicate any of our resource release logic
             self.release_resource()


File: python.info,  Node: Replacing any use of try-finally and flag variables,  Next: Using a context manager as a function decorator,  Prev: Cleaning up in an __enter__ implementation,  Up: Examples and Recipes<3>

5.29.8.6 Replacing any use of ‘try-finally’ and flag variables
..............................................................

A pattern you will sometimes see is a ‘try-finally’ statement with a
flag variable to indicate whether or not the body of the ‘finally’
clause should be executed.  In its simplest form (that can’t already be
handled just by using an ‘except’ clause instead), it looks something
like this:

     cleanup_needed = True
     try:
         result = perform_operation()
         if result:
             cleanup_needed = False
     finally:
         if cleanup_needed:
             cleanup_resources()

As with any ‘try’ statement based code, this can cause problems for
development and review, because the setup code and the cleanup code can
end up being separated by arbitrarily long sections of code.

*note ExitStack: b41. makes it possible to instead register a callback
for execution at the end of a ‘with’ statement, and then later decide to
skip executing that callback:

     from contextlib import ExitStack

     with ExitStack() as stack:
         stack.callback(cleanup_resources)
         result = perform_operation()
         if result:
             stack.pop_all()

This allows the intended cleanup behaviour to be made explicit up front,
rather than requiring a separate flag variable.

If a particular application uses this pattern a lot, it can be
simplified even further by means of a small helper class:

     from contextlib import ExitStack

     class Callback(ExitStack):
         def __init__(self, callback, /, *args, **kwds):
             super().__init__()
             self.callback(callback, *args, **kwds)

         def cancel(self):
             self.pop_all()

     with Callback(cleanup_resources) as cb:
         result = perform_operation()
         if result:
             cb.cancel()

If the resource cleanup isn’t already neatly bundled into a standalone
function, then it is still possible to use the decorator form of *note
ExitStack.callback(): a92. to declare the resource cleanup in advance:

     from contextlib import ExitStack

     with ExitStack() as stack:
         @stack.callback
         def cleanup_resources():
             ...
         result = perform_operation()
         if result:
             stack.pop_all()

Due to the way the decorator protocol works, a callback function
declared this way cannot take any parameters.  Instead, any resources to
be released must be accessed as closure variables.


File: python.info,  Node: Using a context manager as a function decorator,  Prev: Replacing any use of try-finally and flag variables,  Up: Examples and Recipes<3>

5.29.8.7 Using a context manager as a function decorator
........................................................

*note ContextDecorator: 1246. makes it possible to use a context manager
in both an ordinary ‘with’ statement and also as a function decorator.

For example, it is sometimes useful to wrap functions or groups of
statements with a logger that can track the time of entry and time of
exit.  Rather than writing both a function decorator and a context
manager for the task, inheriting from *note ContextDecorator: 1246.
provides both capabilities in a single definition:

     from contextlib import ContextDecorator
     import logging

     logging.basicConfig(level=logging.INFO)

     class track_entry_and_exit(ContextDecorator):
         def __init__(self, name):
             self.name = name

         def __enter__(self):
             logging.info('Entering: %s', self.name)

         def __exit__(self, exc_type, exc, exc_tb):
             logging.info('Exiting: %s', self.name)

Instances of this class can be used as both a context manager:

     with track_entry_and_exit('widget loader'):
         print('Some time consuming activity goes here')
         load_widget()

And also as a function decorator:

     @track_entry_and_exit('widget loader')
     def activity():
         print('Some time consuming activity goes here')
         load_widget()

Note that there is one additional limitation when using context managers
as function decorators: there’s no way to access the return value of
*note __enter__(): 5cb.  If that value is needed, then it is still
necessary to use an explicit ‘with’ statement.

See also
........

PEP 343(1) - The “with” statement

     The specification, background, and examples for the Python *note
     with: 5d5. statement.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0343/


File: python.info,  Node: Single use reusable and reentrant context managers,  Prev: Examples and Recipes<3>,  Up: contextlib — Utilities for with-statement contexts

5.29.8.8 Single use, reusable and reentrant context managers
............................................................

Most context managers are written in a way that means they can only be
used effectively in a *note with: 5d5. statement once.  These single use
context managers must be created afresh each time they’re used -
attempting to use them a second time will trigger an exception or
otherwise not work correctly.

This common limitation means that it is generally advisable to create
context managers directly in the header of the *note with: 5d5.
statement where they are used (as shown in all of the usage examples
above).

Files are an example of effectively single use context managers, since
the first *note with: 5d5. statement will close the file, preventing any
further IO operations using that file object.

Context managers created using *note contextmanager(): 1247. are also
single use context managers, and will complain about the underlying
generator failing to yield if an attempt is made to use them a second
time:

     >>> from contextlib import contextmanager
     >>> @contextmanager
     ... def singleuse():
     ...     print("Before")
     ...     yield
     ...     print("After")
     ...
     >>> cm = singleuse()
     >>> with cm:
     ...     pass
     ...
     Before
     After
     >>> with cm:
     ...     pass
     ...
     Traceback (most recent call last):
         ...
     RuntimeError: generator didn't yield

* Menu:

* Reentrant context managers::
* Reusable context managers::


File: python.info,  Node: Reentrant context managers,  Next: Reusable context managers,  Up: Single use reusable and reentrant context managers

5.29.8.9 Reentrant context managers
...................................

More sophisticated context managers may be “reentrant”.  These context
managers can not only be used in multiple *note with: 5d5. statements,
but may also be used 'inside' a ‘with’ statement that is already using
the same context manager.

*note threading.RLock: 2de. is an example of a reentrant context
manager, as are *note suppress(): f5d, *note redirect_stdout(): e18, and
*note chdir(): 60f.  Here’s a very simple example of reentrant use:

     >>> from contextlib import redirect_stdout
     >>> from io import StringIO
     >>> stream = StringIO()
     >>> write_to_stream = redirect_stdout(stream)
     >>> with write_to_stream:
     ...     print("This is written to the stream rather than stdout")
     ...     with write_to_stream:
     ...         print("This is also written to the stream")
     ...
     >>> print("This is written directly to stdout")
     This is written directly to stdout
     >>> print(stream.getvalue())
     This is written to the stream rather than stdout
     This is also written to the stream

Real world examples of reentrancy are more likely to involve multiple
functions calling each other and hence be far more complicated than this
example.

Note also that being reentrant is 'not' the same thing as being thread
safe.  *note redirect_stdout(): e18, for example, is definitely not
thread safe, as it makes a global modification to the system state by
binding *note sys.stdout: aec. to a different stream.


File: python.info,  Node: Reusable context managers,  Prev: Reentrant context managers,  Up: Single use reusable and reentrant context managers

5.29.8.10 Reusable context managers
...................................

Distinct from both single use and reentrant context managers are
“reusable” context managers (or, to be completely explicit, “reusable,
but not reentrant” context managers, since reentrant context managers
are also reusable).  These context managers support being used multiple
times, but will fail (or otherwise not work correctly) if the specific
context manager instance has already been used in a containing with
statement.

*note threading.Lock: 178a. is an example of a reusable, but not
reentrant, context manager (for a reentrant lock, it is necessary to use
*note threading.RLock: 2de. instead).

Another example of a reusable, but not reentrant, context manager is
*note ExitStack: b41, as it invokes 'all' currently registered callbacks
when leaving any with statement, regardless of where those callbacks
were added:

     >>> from contextlib import ExitStack
     >>> stack = ExitStack()
     >>> with stack:
     ...     stack.callback(print, "Callback: from first context")
     ...     print("Leaving first context")
     ...
     Leaving first context
     Callback: from first context
     >>> with stack:
     ...     stack.callback(print, "Callback: from second context")
     ...     print("Leaving second context")
     ...
     Leaving second context
     Callback: from second context
     >>> with stack:
     ...     stack.callback(print, "Callback: from outer context")
     ...     with stack:
     ...         stack.callback(print, "Callback: from inner context")
     ...         print("Leaving inner context")
     ...     print("Leaving outer context")
     ...
     Leaving inner context
     Callback: from inner context
     Callback: from outer context
     Leaving outer context

As the output from the example shows, reusing a single stack object
across multiple with statements works correctly, but attempting to nest
them will cause the stack to be cleared at the end of the innermost with
statement, which is unlikely to be desirable behaviour.

Using separate *note ExitStack: b41. instances instead of reusing a
single instance avoids that problem:

     >>> from contextlib import ExitStack
     >>> with ExitStack() as outer_stack:
     ...     outer_stack.callback(print, "Callback: from outer context")
     ...     with ExitStack() as inner_stack:
     ...         inner_stack.callback(print, "Callback: from inner context")
     ...         print("Leaving inner context")
     ...     print("Leaving outer context")
     ...
     Leaving inner context
     Callback: from inner context
     Leaving outer context
     Callback: from outer context


File: python.info,  Node: abc — Abstract Base Classes,  Next: atexit — Exit handlers,  Prev: contextlib — Utilities for with-statement contexts,  Up: Python Runtime Services

5.29.9 ‘abc’ — Abstract Base Classes
------------------------------------

'Source code:' Lib/abc.py(1)

__________________________________________________________________

This module provides the infrastructure for defining *note abstract base
classes: 11fa. (ABCs) in Python, as outlined in PEP 3119(2); see the PEP
for why this was added to Python.  (See also PEP 3141(3) and the *note
numbers: 9e. module regarding a type hierarchy for numbers based on
ABCs.)

The *note collections: 1d. module has some concrete classes that derive
from ABCs; these can, of course, be further derived.  In addition, the
*note collections.abc: 1e. submodule has some ABCs that can be used to
test whether a class or instance provides a particular interface, for
example, if it is *note hashable: 613. or if it is a *note mapping:
1200.

This module provides the metaclass *note ABCMeta: f4f. for defining ABCs
and a helper class *note ABC: f4e. to alternatively define ABCs through
inheritance:

 -- Class: abc.ABC

     A helper class that has *note ABCMeta: f4f. as its metaclass.  With
     this class, an abstract base class can be created by simply
     deriving from ‘ABC’ avoiding sometimes confusing metaclass usage,
     for example:

          from abc import ABC

          class MyABC(ABC):
              pass

     Note that the type of ‘ABC’ is still *note ABCMeta: f4f, therefore
     inheriting from ‘ABC’ requires the usual precautions regarding
     metaclass usage, as multiple inheritance may lead to metaclass
     conflicts.  One may also define an abstract base class by passing
     the metaclass keyword and using ‘ABCMeta’ directly, for example:

          from abc import ABCMeta

          class MyABC(metaclass=ABCMeta):
              pass

     Added in version 3.4.

 -- Class: abc.ABCMeta

     Metaclass for defining Abstract Base Classes (ABCs).

     Use this metaclass to create an ABC. An ABC can be subclassed
     directly, and then acts as a mix-in class.  You can also register
     unrelated concrete classes (even built-in classes) and unrelated
     ABCs as “virtual subclasses” – these and their descendants will be
     considered subclasses of the registering ABC by the built-in *note
     issubclass(): 7c5. function, but the registering ABC won’t show up
     in their MRO (Method Resolution Order) nor will method
     implementations defined by the registering ABC be callable (not
     even via *note super(): 4de.).  (4)

     Classes created with a metaclass of ‘ABCMeta’ have the following
     method:

      -- Method: register (subclass)

          Register 'subclass' as a “virtual subclass” of this ABC. For
          example:

               from abc import ABC

               class MyABC(ABC):
                   pass

               MyABC.register(tuple)

               assert issubclass(tuple, MyABC)
               assert isinstance((), MyABC)

          Changed in version 3.3: Returns the registered subclass, to
          allow usage as a class decorator.

          Changed in version 3.4: To detect calls to ‘register()’, you
          can use the *note get_cache_token(): f4d. function.

     You can also override this method in an abstract base class:

      -- Method: __subclasshook__ (subclass)

          (Must be defined as a class method.)

          Check whether 'subclass' is considered a subclass of this ABC.
          This means that you can customize the behavior of *note
          issubclass(): 7c5. further without the need to call *note
          register(): 10cc. on every class you want to consider a
          subclass of the ABC. (This class method is called from the
          *note __subclasscheck__(): 212d. method of the ABC.)

          This method should return ‘True’, ‘False’ or *note
          NotImplemented: 7d6.  If it returns ‘True’, the 'subclass' is
          considered a subclass of this ABC. If it returns ‘False’, the
          'subclass' is not considered a subclass of this ABC, even if
          it would normally be one.  If it returns ‘NotImplemented’, the
          subclass check is continued with the usual mechanism.

     For a demonstration of these concepts, look at this example ABC
     definition:

          class Foo:
              def __getitem__(self, index):
                  ...
              def __len__(self):
                  ...
              def get_iterator(self):
                  return iter(self)

          class MyIterable(ABC):

              @abstractmethod
              def __iter__(self):
                  while False:
                      yield None

              def get_iterator(self):
                  return self.__iter__()

              @classmethod
              def __subclasshook__(cls, C):
                  if cls is MyIterable:
                      if any("__iter__" in B.__dict__ for B in C.__mro__):
                          return True
                  return NotImplemented

          MyIterable.register(Foo)

     The ABC ‘MyIterable’ defines the standard iterable method, *note
     __iter__(): c90, as an abstract method.  The implementation given
     here can still be called from subclasses.  The ‘get_iterator()’
     method is also part of the ‘MyIterable’ abstract base class, but it
     does not have to be overridden in non-abstract derived classes.

     The *note __subclasshook__(): 26e8. class method defined here says
     that any class that has an *note __iter__(): c90. method in its
     *note __dict__: 55e. (or in that of one of its base classes,
     accessed via the *note __mro__: 20da. list) is considered a
     ‘MyIterable’ too.

     Finally, the last line makes ‘Foo’ a virtual subclass of
     ‘MyIterable’, even though it does not define an *note __iter__():
     c90. method (it uses the old-style iterable protocol, defined in
     terms of *note __len__(): 15da. and *note __getitem__(): 283.).
     Note that this will not make ‘get_iterator’ available as a method
     of ‘Foo’, so it is provided separately.

The ‘abc’ module also provides the following decorator:

 -- Function: @abc.abstractmethod

     A decorator indicating abstract methods.

     Using this decorator requires that the class’s metaclass is *note
     ABCMeta: f4f. or is derived from it.  A class that has a metaclass
     derived from ‘ABCMeta’ cannot be instantiated unless all of its
     abstract methods and properties are overridden.  The abstract
     methods can be called using any of the normal ‘super’ call
     mechanisms.  ‘abstractmethod()’ may be used to declare abstract
     methods for properties and descriptors.

     Dynamically adding abstract methods to a class, or attempting to
     modify the abstraction status of a method or class once it is
     created, are only supported using the *note
     update_abstractmethods(): 468f. function.  The ‘abstractmethod()’
     only affects subclasses derived using regular inheritance; “virtual
     subclasses” registered with the ABC’s *note register(): 10cc.
     method are not affected.

     When ‘abstractmethod()’ is applied in combination with other method
     descriptors, it should be applied as the innermost decorator, as
     shown in the following usage examples:

          class C(ABC):
              @abstractmethod
              def my_abstract_method(self, arg1):
                  ...
              @classmethod
              @abstractmethod
              def my_abstract_classmethod(cls, arg2):
                  ...
              @staticmethod
              @abstractmethod
              def my_abstract_staticmethod(arg3):
                  ...

              @property
              @abstractmethod
              def my_abstract_property(self):
                  ...
              @my_abstract_property.setter
              @abstractmethod
              def my_abstract_property(self, val):
                  ...

              @abstractmethod
              def _get_x(self):
                  ...
              @abstractmethod
              def _set_x(self, val):
                  ...
              x = property(_get_x, _set_x)

     In order to correctly interoperate with the abstract base class
     machinery, the descriptor must identify itself as abstract using
     ‘__isabstractmethod__’.  In general, this attribute should be
     ‘True’ if any of the methods used to compose the descriptor are
     abstract.  For example, Python’s built-in *note property: 194. does
     the equivalent of:

          class Descriptor:
              ...
              @property
              def __isabstractmethod__(self):
                  return any(getattr(f, '__isabstractmethod__', False) for
                             f in (self._fget, self._fset, self._fdel))

          Note: Unlike Java abstract methods, these abstract methods may
          have an implementation.  This implementation can be called via
          the *note super(): 4de. mechanism from the class that
          overrides it.  This could be useful as an end-point for a
          super-call in a framework that uses cooperative
          multiple-inheritance.

The ‘abc’ module also supports the following legacy decorators:

 -- Function: @abc.abstractclassmethod

     Added in version 3.2.

     Deprecated since version 3.3: It is now possible to use *note
     classmethod: 166. with *note abstractmethod(): 10c9, making this
     decorator redundant.

     A subclass of the built-in *note classmethod(): 166, indicating an
     abstract classmethod.  Otherwise it is similar to *note
     abstractmethod(): 10c9.

     This special case is deprecated, as the *note classmethod(): 166.
     decorator is now correctly identified as abstract when applied to
     an abstract method:

          class C(ABC):
              @classmethod
              @abstractmethod
              def my_abstract_classmethod(cls, arg):
                  ...

 -- Function: @abc.abstractstaticmethod

     Added in version 3.2.

     Deprecated since version 3.3: It is now possible to use *note
     staticmethod: 419. with *note abstractmethod(): 10c9, making this
     decorator redundant.

     A subclass of the built-in *note staticmethod(): 419, indicating an
     abstract staticmethod.  Otherwise it is similar to *note
     abstractmethod(): 10c9.

     This special case is deprecated, as the *note staticmethod(): 419.
     decorator is now correctly identified as abstract when applied to
     an abstract method:

          class C(ABC):
              @staticmethod
              @abstractmethod
              def my_abstract_staticmethod(arg):
                  ...

 -- Function: @abc.abstractproperty

     Deprecated since version 3.3: It is now possible to use *note
     property: 194, *note property.getter(): 176d, *note
     property.setter(): 176e. and *note property.deleter(): 176f. with
     *note abstractmethod(): 10c9, making this decorator redundant.

     A subclass of the built-in *note property(): 194, indicating an
     abstract property.

     This special case is deprecated, as the *note property(): 194.
     decorator is now correctly identified as abstract when applied to
     an abstract method:

          class C(ABC):
              @property
              @abstractmethod
              def my_abstract_property(self):
                  ...

     The above example defines a read-only property; you can also define
     a read-write abstract property by appropriately marking one or more
     of the underlying methods as abstract:

          class C(ABC):
              @property
              def x(self):
                  ...

              @x.setter
              @abstractmethod
              def x(self, val):
                  ...

     If only some components are abstract, only those components need to
     be updated to create a concrete property in a subclass:

          class D(C):
              @C.x.setter
              def x(self, val):
                  ...

The ‘abc’ module also provides the following functions:

 -- Function: abc.get_cache_token ()

     Returns the current abstract base class cache token.

     The token is an opaque object (that supports equality testing)
     identifying the current version of the abstract base class cache
     for virtual subclasses.  The token changes with every call to *note
     ABCMeta.register(): 10cc. on any ABC.

     Added in version 3.4.

 -- Function: abc.update_abstractmethods (cls)

     A function to recalculate an abstract class’s abstraction status.
     This function should be called if a class’s abstract methods have
     been implemented or changed after it was created.  Usually, this
     function should be called from within a class decorator.

     Returns 'cls', to allow usage as a class decorator.

     If 'cls' is not an instance of *note ABCMeta: f4f, does nothing.

          Note: This function assumes that 'cls'’s superclasses are
          already updated.  It does not update any subclasses.

     Added in version 3.10.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/abc.py

   (2) https://peps.python.org/pep-3119/

   (3) https://peps.python.org/pep-3141/

   (4) C++ programmers should note that Python’s virtual base class
concept is not the same as C++’s.


File: python.info,  Node: atexit — Exit handlers,  Next: traceback — Print or retrieve a stack traceback,  Prev: abc — Abstract Base Classes,  Up: Python Runtime Services

5.29.10 ‘atexit’ — Exit handlers
--------------------------------

__________________________________________________________________

The ‘atexit’ module defines functions to register and unregister cleanup
functions.  Functions thus registered are automatically executed upon
normal interpreter termination.  ‘atexit’ runs these functions in the
'reverse' order in which they were registered; if you register ‘A’, ‘B’,
and ‘C’, at interpreter termination time they will be run in the order
‘C’, ‘B’, ‘A’.

'Note:' The functions registered via this module are not called when the
program is killed by a signal not handled by Python, when a Python fatal
internal error is detected, or when *note os._exit(): 2451. is called.

'Note:' The effect of registering or unregistering functions from within
a cleanup function is undefined.

Changed in version 3.7: When used with C-API subinterpreters, registered
functions are local to the interpreter they were registered in.

 -- Function: atexit.register (func, *args, **kwargs)

     Register 'func' as a function to be executed at termination.  Any
     optional arguments that are to be passed to 'func' must be passed
     as arguments to ‘register()’.  It is possible to register the same
     function and arguments more than once.

     At normal program termination (for instance, if *note sys.exit():
     1394. is called or the main module’s execution completes), all
     functions registered are called in last in, first out order.  The
     assumption is that lower level modules will normally be imported
     before higher level modules and thus must be cleaned up later.

     If an exception is raised during execution of the exit handlers, a
     traceback is printed (unless *note SystemExit: d69. is raised) and
     the exception information is saved.  After all exit handlers have
     had a chance to run, the last exception to be raised is re-raised.

     This function returns 'func', which makes it possible to use it as
     a decorator.

          Warning: Starting new threads or calling *note os.fork(): 197.
          from a registered function can lead to race condition between
          the main Python runtime thread freeing thread states while
          internal *note threading: ed. routines or the new process try
          to use that state.  This can lead to crashes rather than clean
          shutdown.

     Changed in version 3.12: Attempts to start a new thread or *note
     os.fork(): 197. a new process in a registered function now leads to
     *note RuntimeError: 195.

 -- Function: atexit.unregister (func)

     Remove 'func' from the list of functions to be run at interpreter
     shutdown.  ‘unregister()’ silently does nothing if 'func' was not
     previously registered.  If 'func' has been registered more than
     once, every occurrence of that function in the ‘atexit’ call stack
     will be removed.  Equality comparisons (‘==’) are used internally
     during unregistration, so function references do not need to have
     matching identities.

See also
........

Module *note readline: ba.

     Useful example of ‘atexit’ to read and write *note readline: ba.
     history files.

* Menu:

* atexit Example::


File: python.info,  Node: atexit Example,  Up: atexit — Exit handlers

5.29.10.1 ‘atexit’ Example
..........................

The following simple example demonstrates how a module can initialize a
counter from a file when it is imported and save the counter’s updated
value automatically when the program terminates without relying on the
application making an explicit call into this module at termination.

     try:
         with open('counterfile') as infile:
             _count = int(infile.read())
     except FileNotFoundError:
         _count = 0

     def incrcounter(n):
         global _count
         _count = _count + n

     def savecounter():
         with open('counterfile', 'w') as outfile:
             outfile.write('%d' % _count)

     import atexit

     atexit.register(savecounter)

Positional and keyword arguments may also be passed to *note register():
885. to be passed along to the registered function when it is called:

     def goodbye(name, adjective):
         print('Goodbye %s, it was %s to meet you.' % (name, adjective))

     import atexit

     atexit.register(goodbye, 'Donny', 'nice')
     # or:
     atexit.register(goodbye, adjective='nice', name='Donny')

Usage as a *note decorator: 734.:

     import atexit

     @atexit.register
     def goodbye():
         print('You are now leaving the Python sector.')

This only works with functions that can be called without arguments.


File: python.info,  Node: traceback — Print or retrieve a stack traceback,  Next: __future__ — Future statement definitions,  Prev: atexit — Exit handlers,  Up: Python Runtime Services

5.29.11 ‘traceback’ — Print or retrieve a stack traceback
---------------------------------------------------------

'Source code:' Lib/traceback.py(1)

__________________________________________________________________

This module provides a standard interface to extract, format and print
stack traces of Python programs.  It is more flexible than the
interpreter’s default traceback display, and therefore makes it possible
to configure certain aspects of the output.  Finally, it contains a
utility for capturing enough information about an exception to print it
later, without the need to save a reference to the actual exception.
Since exceptions can be the roots of large objects graph, this utility
can significantly improve memory management.

The module uses *note traceback objects: b0d. — these are objects of
type *note types.TracebackType: b0b, which are assigned to the *note
__traceback__: 130e. field of *note BaseException: 5be. instances.

See also
........

Module *note faulthandler: 58.

     Used to dump Python tracebacks explicitly, on a fault, after a
     timeout, or on a user signal.

Module *note pdb: a5.

     Interactive source code debugger for Python programs.

The module’s API can be divided into two parts:

   * Module-level functions offering basic functionality, which are
     useful for interactive inspection of exceptions and tracebacks.

   * *note TracebackException: 25c. class and its helper classes *note
     StackSummary: eb7. and *note FrameSummary: eb8.  These offer both
     more flexibility in the output generated and the ability to store
     the information necessary for later formatting without holding
     references to actual exception and traceback objects.

* Menu:

* Module-Level Functions: Module-Level Functions<2>.
* TracebackException Objects::
* StackSummary Objects::
* FrameSummary Objects::
* Examples of Using the Module-Level Functions::
* Examples of Using TracebackException::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/traceback.py


File: python.info,  Node: Module-Level Functions<2>,  Next: TracebackException Objects,  Up: traceback — Print or retrieve a stack traceback

5.29.11.1 Module-Level Functions
................................

 -- Function: traceback.print_tb (tb, limit=None, file=None)

     Print up to 'limit' stack trace entries from *note traceback
     object: b0d. 'tb' (starting from the caller’s frame) if 'limit' is
     positive.  Otherwise, print the last ‘abs(limit)’ entries.  If
     'limit' is omitted or ‘None’, all entries are printed.  If 'file'
     is omitted or ‘None’, the output goes to *note sys.stderr: 943.;
     otherwise it should be an open *note file: 1208. or *note file-like
     object: 15f4. to receive the output.

          Note: The meaning of the 'limit' parameter is different than
          the meaning of *note sys.tracebacklimit: 16e2.  A negative
          'limit' value corresponds to a positive value of
          ‘sys.tracebacklimit’, whereas the behaviour of a positive
          'limit' value cannot be achieved with ‘sys.tracebacklimit’.

     Changed in version 3.5: Added negative 'limit' support.

 -- Function: traceback.print_exception (exc, /[, value, tb],
          limit=None, file=None, chain=True)

     Print exception information and stack trace entries from *note
     traceback object: b0d. 'tb' to 'file'.  This differs from *note
     print_tb(): eb9. in the following ways:

        * if 'tb' is not ‘None’, it prints a header ‘Traceback (most
          recent call last):’

        * it prints the exception type and 'value' after the stack trace

        * if 'type(value)' is *note SyntaxError: 18d. and 'value' has
          the appropriate format, it prints the line where the syntax
          error occurred with a caret indicating the approximate
          position of the error.

     Since Python 3.10, instead of passing 'value' and 'tb', an
     exception object can be passed as the first argument.  If 'value'
     and 'tb' are provided, the first argument is ignored in order to
     provide backwards compatibility.

     The optional 'limit' argument has the same meaning as for *note
     print_tb(): eb9.  If 'chain' is true (the default), then chained
     exceptions (the *note __cause__: 1310. or *note __context__: 130f.
     attributes of the exception) will be printed as well, like the
     interpreter itself does when printing an unhandled exception.

     Changed in version 3.5: The 'etype' argument is ignored and
     inferred from the type of 'value'.

     Changed in version 3.10: The 'etype' parameter has been renamed to
     'exc' and is now positional-only.

 -- Function: traceback.print_exc (limit=None, file=None, chain=True)

     This is a shorthand for ‘print_exception(sys.exception(),
     limit=limit, file=file, chain=chain)’.

 -- Function: traceback.print_last (limit=None, file=None, chain=True)

     This is a shorthand for ‘print_exception(sys.last_exc, limit=limit,
     file=file, chain=chain)’.  In general it will work only after an
     exception has reached an interactive prompt (see *note
     sys.last_exc: 4c1.).

 -- Function: traceback.print_stack (f=None, limit=None, file=None)

     Print up to 'limit' stack trace entries (starting from the
     invocation point) if 'limit' is positive.  Otherwise, print the
     last ‘abs(limit)’ entries.  If 'limit' is omitted or ‘None’, all
     entries are printed.  The optional 'f' argument can be used to
     specify an alternate *note stack frame: 6e3. to start.  The
     optional 'file' argument has the same meaning as for *note
     print_tb(): eb9.

     Changed in version 3.5: Added negative 'limit' support.

 -- Function: traceback.extract_tb (tb, limit=None)

     Return a *note StackSummary: eb7. object representing a list of
     “pre-processed” stack trace entries extracted from the *note
     traceback object: b0d. 'tb'.  It is useful for alternate formatting
     of stack traces.  The optional 'limit' argument has the same
     meaning as for *note print_tb(): eb9.  A “pre-processed” stack
     trace entry is a *note FrameSummary: eb8. object containing
     attributes *note filename: 469b, *note lineno: 469c, *note name:
     469d, and *note line: 469e. representing the information that is
     usually printed for a stack trace.

 -- Function: traceback.extract_stack (f=None, limit=None)

     Extract the raw traceback from the current *note stack frame: 6e3.
     The return value has the same format as for *note extract_tb():
     469a.  The optional 'f' and 'limit' arguments have the same meaning
     as for *note print_stack(): eba.

 -- Function: traceback.print_list (extracted_list, file=None)

     Print the list of tuples as returned by *note extract_tb(): 469a.
     or *note extract_stack(): 469f. as a formatted stack trace to the
     given file.  If 'file' is ‘None’, the output is written to *note
     sys.stderr: 943.

 -- Function: traceback.format_list (extracted_list)

     Given a list of tuples or *note FrameSummary: eb8. objects as
     returned by *note extract_tb(): 469a. or *note extract_stack():
     469f, return a list of strings ready for printing.  Each string in
     the resulting list corresponds to the item with the same index in
     the argument list.  Each string ends in a newline; the strings may
     contain internal newlines as well, for those items whose source
     text line is not ‘None’.

 -- Function: traceback.format_exception_only (exc, /[, value], *,
          show_group=False)

     Format the exception part of a traceback using an exception value
     such as given by *note sys.last_value: 4c3.  The return value is a
     list of strings, each ending in a newline.  The list contains the
     exception’s message, which is normally a single string; however,
     for *note SyntaxError: 18d. exceptions, it contains several lines
     that (when printed) display detailed information about where the
     syntax error occurred.  Following the message, the list contains
     the exception’s *note notes: 243c.

     Since Python 3.10, instead of passing 'value', an exception object
     can be passed as the first argument.  If 'value' is provided, the
     first argument is ignored in order to provide backwards
     compatibility.

     When 'show_group' is ‘True’, and the exception is an instance of
     *note BaseExceptionGroup: 25f, the nested exceptions are included
     as well, recursively, with indentation relative to their nesting
     depth.

     Changed in version 3.10: The 'etype' parameter has been renamed to
     'exc' and is now positional-only.

     Changed in version 3.11: The returned list now includes any *note
     notes: 243c. attached to the exception.

     Changed in version 3.13: 'show_group' parameter was added.

 -- Function: traceback.format_exception (exc, /[, value, tb],
          limit=None, chain=True)

     Format a stack trace and the exception information.  The arguments
     have the same meaning as the corresponding arguments to *note
     print_exception(): 855.  The return value is a list of strings,
     each ending in a newline and some containing internal newlines.
     When these lines are concatenated and printed, exactly the same
     text is printed as does ‘print_exception()’.

     Changed in version 3.5: The 'etype' argument is ignored and
     inferred from the type of 'value'.

     Changed in version 3.10: This function’s behavior and signature
     were modified to match *note print_exception(): 855.

 -- Function: traceback.format_exc (limit=None, chain=True)

     This is like ‘print_exc(limit)’ but returns a string instead of
     printing to a file.

 -- Function: traceback.format_tb (tb, limit=None)

     A shorthand for ‘format_list(extract_tb(tb, limit))’.

 -- Function: traceback.format_stack (f=None, limit=None)

     A shorthand for ‘format_list(extract_stack(f, limit))’.

 -- Function: traceback.clear_frames (tb)

     Clears the local variables of all the stack frames in a *note
     traceback: b0d. 'tb' by calling the *note clear(): 280. method of
     each *note frame object: 6e3.

     Added in version 3.4.

 -- Function: traceback.walk_stack (f)

     Walk a stack following *note f.f_back: 78f. from the given frame,
     yielding the frame and line number for each frame.  If 'f' is
     ‘None’, the current stack is used.  This helper is used with *note
     StackSummary.extract(): 46a4.

     Added in version 3.5.

 -- Function: traceback.walk_tb (tb)

     Walk a traceback following *note tb_next: b0c. yielding the frame
     and line number for each frame.  This helper is used with *note
     StackSummary.extract(): 46a4.

     Added in version 3.5.


File: python.info,  Node: TracebackException Objects,  Next: StackSummary Objects,  Prev: Module-Level Functions<2>,  Up: traceback — Print or retrieve a stack traceback

5.29.11.2 ‘TracebackException’ Objects
......................................

Added in version 3.5.

‘TracebackException’ objects are created from actual exceptions to
capture data for later printing.  They offer a more lightweight method
of storing this information by avoiding holding references to *note
traceback: b0d. and *note frame: 6e3. objects.  In addition, they expose
more options to configure the output compared to the module-level
functions described above.

 -- Class: traceback.TracebackException (exc_type, exc_value,
          exc_traceback, *, limit=None, lookup_lines=True,
          capture_locals=False, compact=False, max_group_width=15,
          max_group_depth=10)

     Capture an exception for later rendering.  The meaning of 'limit',
     'lookup_lines' and 'capture_locals' are as for the *note
     StackSummary: eb7. class.

     If 'compact' is true, only data that is required by
     ‘TracebackException’’s *note format(): 622. method is saved in the
     class attributes.  In particular, the *note __context__: 46a6.
     field is calculated only if *note __cause__: 46a7. is ‘None’ and
     *note __suppress_context__: 46a8. is false.

     Note that when locals are captured, they are also shown in the
     traceback.

     'max_group_width' and 'max_group_depth' control the formatting of
     exception groups (see *note BaseExceptionGroup: 25f.).  The depth
     refers to the nesting level of the group, and the width refers to
     the size of a single exception group’s exceptions array.  The
     formatted output is truncated when either limit is exceeded.

     Changed in version 3.10: Added the 'compact' parameter.

     Changed in version 3.11: Added the 'max_group_width' and
     'max_group_depth' parameters.

      -- Attribute: __cause__

          A ‘TracebackException’ of the original *note __cause__: 1310.

      -- Attribute: __context__

          A ‘TracebackException’ of the original *note __context__:
          130f.

      -- Attribute: exceptions

          If ‘self’ represents an *note ExceptionGroup: 1b6, this field
          holds a list of ‘TracebackException’ instances representing
          the nested exceptions.  Otherwise it is ‘None’.

          Added in version 3.11.

      -- Attribute: __suppress_context__

          The *note __suppress_context__: 226d. value from the original
          exception.

      -- Attribute: __notes__

          The *note __notes__: 243c. value from the original exception,
          or ‘None’ if the exception does not have any notes.  If it is
          not ‘None’ is it formatted in the traceback after the
          exception string.

          Added in version 3.11.

      -- Attribute: stack

          A *note StackSummary: eb7. representing the traceback.

      -- Attribute: exc_type

          The class of the original traceback.

          Deprecated since version 3.13.

      -- Attribute: exc_type_str

          String display of the class of the original exception.

          Added in version 3.13.

      -- Attribute: filename

          For syntax errors - the file name where the error occurred.

      -- Attribute: lineno

          For syntax errors - the line number where the error occurred.

      -- Attribute: end_lineno

          For syntax errors - the end line number where the error
          occurred.  Can be ‘None’ if not present.

          Added in version 3.10.

      -- Attribute: text

          For syntax errors - the text where the error occurred.

      -- Attribute: offset

          For syntax errors - the offset into the text where the error
          occurred.

      -- Attribute: end_offset

          For syntax errors - the end offset into the text where the
          error occurred.  Can be ‘None’ if not present.

          Added in version 3.10.

      -- Attribute: msg

          For syntax errors - the compiler error message.

      -- Method: classmethod from_exception (exc, *, limit=None,
               lookup_lines=True, capture_locals=False)

          Capture an exception for later rendering.  'limit',
          'lookup_lines' and 'capture_locals' are as for the *note
          StackSummary: eb7. class.

          Note that when locals are captured, they are also shown in the
          traceback.

      -- Method: print (*, file=None, chain=True)

          Print to 'file' (default ‘sys.stderr’) the exception
          information returned by *note format(): 622.

          Added in version 3.11.

      -- Method: format (*, chain=True)

          Format the exception.

          If 'chain' is not ‘True’, *note __cause__: 46a7. and *note
          __context__: 46a6. will not be formatted.

          The return value is a generator of strings, each ending in a
          newline and some containing internal newlines.  *note
          print_exception(): 855. is a wrapper around this method which
          just prints the lines to a file.

      -- Method: format_exception_only (*, show_group=False)

          Format the exception part of the traceback.

          The return value is a generator of strings, each ending in a
          newline.

          When 'show_group' is ‘False’, the generator emits the
          exception’s message followed by its notes (if it has any).
          The exception message is normally a single string; however,
          for *note SyntaxError: 18d. exceptions, it consists of several
          lines that (when printed) display detailed information about
          where the syntax error occurred.

          When 'show_group' is ‘True’, and the exception is an instance
          of *note BaseExceptionGroup: 25f, the nested exceptions are
          included as well, recursively, with indentation relative to
          their nesting depth.

          Changed in version 3.11: The exception’s *note notes: 243c.
          are now included in the output.

          Changed in version 3.13: Added the 'show_group' parameter.


File: python.info,  Node: StackSummary Objects,  Next: FrameSummary Objects,  Prev: TracebackException Objects,  Up: traceback — Print or retrieve a stack traceback

5.29.11.3 ‘StackSummary’ Objects
................................

Added in version 3.5.

‘StackSummary’ objects represent a call stack ready for formatting.

 -- Class: traceback.StackSummary

      -- Method: classmethod extract (frame_gen, *, limit=None,
               lookup_lines=True, capture_locals=False)

          Construct a ‘StackSummary’ object from a frame generator (such
          as is returned by *note walk_stack(): eb5. or *note walk_tb():
          eb6.).

          If 'limit' is supplied, only this many frames are taken from
          'frame_gen'.  If 'lookup_lines' is ‘False’, the returned *note
          FrameSummary: eb8. objects will not have read their lines in
          yet, making the cost of creating the ‘StackSummary’ cheaper
          (which may be valuable if it may not actually get formatted).
          If 'capture_locals' is ‘True’ the local variables in each
          ‘FrameSummary’ are captured as object representations.

          Changed in version 3.12: Exceptions raised from *note repr():
          803. on a local variable (when 'capture_locals' is ‘True’) are
          no longer propagated to the caller.

      -- Method: classmethod from_list (a_list)

          Construct a ‘StackSummary’ object from a supplied list of
          *note FrameSummary: eb8. objects or old-style list of tuples.
          Each tuple should be a 4-tuple with 'filename', 'lineno',
          'name', 'line' as the elements.

      -- Method: format ()

          Returns a list of strings ready for printing.  Each string in
          the resulting list corresponds to a single *note frame: 6e3.
          from the stack.  Each string ends in a newline; the strings
          may contain internal newlines as well, for those items with
          source text lines.

          For long sequences of the same frame and line, the first few
          repetitions are shown, followed by a summary line stating the
          exact number of further repetitions.

          Changed in version 3.6: Long sequences of repeated frames are
          now abbreviated.

      -- Method: format_frame_summary (frame_summary)

          Returns a string for printing one of the *note frames: 6e3.
          involved in the stack.  This method is called for each *note
          FrameSummary: eb8. object to be printed by *note
          StackSummary.format(): 46b7.  If it returns ‘None’, the frame
          is omitted from the output.

          Added in version 3.11.


File: python.info,  Node: FrameSummary Objects,  Next: Examples of Using the Module-Level Functions,  Prev: StackSummary Objects,  Up: traceback — Print or retrieve a stack traceback

5.29.11.4 ‘FrameSummary’ Objects
................................

Added in version 3.5.

A ‘FrameSummary’ object represents a single *note frame: 6e3. in a *note
traceback: b0d.

 -- Class: traceback.FrameSummary (filename, lineno, name, *,
          lookup_line=True, locals=None, line=None, end_lineno=None,
          colno=None, end_colno=None)

     Represents a single *note frame: 6e3. in the *note traceback: b0d.
     or stack that is being formatted or printed.  It may optionally
     have a stringified version of the frame’s locals included in it.
     If 'lookup_line' is ‘False’, the source code is not looked up until
     the ‘FrameSummary’ has the *note line: 469e. attribute accessed
     (which also happens when casting it to a *note tuple: 373.).
     ‘line’ may be directly provided, and will prevent line lookups
     happening at all.  'locals' is an optional local variable mapping,
     and if supplied the variable representations are stored in the
     summary for later display.

     ‘FrameSummary’ instances have the following attributes:

      -- Attribute: filename

          The filename of the source code for this frame.  Equivalent to
          accessing *note f.f_code.co_filename: 13ba. on a *note frame
          object: 6e3. 'f'.

      -- Attribute: lineno

          The line number of the source code for this frame.

      -- Attribute: name

          Equivalent to accessing *note f.f_code.co_name: 20eb. on a
          *note frame object: 6e3. 'f'.

      -- Attribute: line

          A string representing the source code for this frame, with
          leading and trailing whitespace stripped.  If the source is
          not available, it is ‘None’.

      -- Attribute: end_lineno

          The last line number of the source code for this frame.  By
          default, it is set to ‘lineno’ and indexation starts from 1.

          Changed in version 3.13: The default value changed from ‘None’
          to ‘lineno’.

      -- Attribute: colno

          The column number of the source code for this frame.  By
          default, it is ‘None’ and indexation starts from 0.

      -- Attribute: end_colno

          The last column number of the source code for this frame.  By
          default, it is ‘None’ and indexation starts from 0.


File: python.info,  Node: Examples of Using the Module-Level Functions,  Next: Examples of Using TracebackException,  Prev: FrameSummary Objects,  Up: traceback — Print or retrieve a stack traceback

5.29.11.5 Examples of Using the Module-Level Functions
......................................................

This simple example implements a basic read-eval-print loop, similar to
(but less useful than) the standard Python interactive interpreter loop.
For a more complete implementation of the interpreter loop, refer to the
*note code: 1a. module.

     import sys, traceback

     def run_user_code(envdir):
         source = input(">>> ")
         try:
             exec(source, envdir)
         except Exception:
             print("Exception in user code:")
             print("-"*60)
             traceback.print_exc(file=sys.stdout)
             print("-"*60)

     envdir = {}
     while True:
         run_user_code(envdir)

The following example demonstrates the different ways to print and
format the exception and traceback:

     import sys, traceback

     def lumberjack():
         bright_side_of_life()

     def bright_side_of_life():
         return tuple()[0]

     try:
         lumberjack()
     except IndexError as exc:
         print("*** print_tb:")
         traceback.print_tb(exc.__traceback__, limit=1, file=sys.stdout)
         print("*** print_exception:")
         traceback.print_exception(exc, limit=2, file=sys.stdout)
         print("*** print_exc:")
         traceback.print_exc(limit=2, file=sys.stdout)
         print("*** format_exc, first and last line:")
         formatted_lines = traceback.format_exc().splitlines()
         print(formatted_lines[0])
         print(formatted_lines[-1])
         print("*** format_exception:")
         print(repr(traceback.format_exception(exc)))
         print("*** extract_tb:")
         print(repr(traceback.extract_tb(exc.__traceback__)))
         print("*** format_tb:")
         print(repr(traceback.format_tb(exc.__traceback__)))
         print("*** tb_lineno:", exc.__traceback__.tb_lineno)

The output for the example would look similar to this:

     *** print_tb:
       File "<doctest...>", line 10, in <module>
         lumberjack()
         ~~~~~~~~~~^^
     *** print_exception:
     Traceback (most recent call last):
       File "<doctest...>", line 10, in <module>
         lumberjack()
         ~~~~~~~~~~^^
       File "<doctest...>", line 4, in lumberjack
         bright_side_of_life()
         ~~~~~~~~~~~~~~~~~~~^^
     IndexError: tuple index out of range
     *** print_exc:
     Traceback (most recent call last):
       File "<doctest...>", line 10, in <module>
         lumberjack()
         ~~~~~~~~~~^^
       File "<doctest...>", line 4, in lumberjack
         bright_side_of_life()
         ~~~~~~~~~~~~~~~~~~~^^
     IndexError: tuple index out of range
     *** format_exc, first and last line:
     Traceback (most recent call last):
     IndexError: tuple index out of range
     *** format_exception:
     ['Traceback (most recent call last):\n',
      '  File "<doctest default[0]>", line 10, in <module>\n    lumberjack()\n    ~~~~~~~~~~^^\n',
      '  File "<doctest default[0]>", line 4, in lumberjack\n    bright_side_of_life()\n    ~~~~~~~~~~~~~~~~~~~^^\n',
      '  File "<doctest default[0]>", line 7, in bright_side_of_life\n    return tuple()[0]\n           ~~~~~~~^^^\n',
      'IndexError: tuple index out of range\n']
     *** extract_tb:
     [<FrameSummary file <doctest...>, line 10 in <module>>,
      <FrameSummary file <doctest...>, line 4 in lumberjack>,
      <FrameSummary file <doctest...>, line 7 in bright_side_of_life>]
     *** format_tb:
     ['  File "<doctest default[0]>", line 10, in <module>\n    lumberjack()\n    ~~~~~~~~~~^^\n',
      '  File "<doctest default[0]>", line 4, in lumberjack\n    bright_side_of_life()\n    ~~~~~~~~~~~~~~~~~~~^^\n',
      '  File "<doctest default[0]>", line 7, in bright_side_of_life\n    return tuple()[0]\n           ~~~~~~~^^^\n']
     *** tb_lineno: 10

The following example shows the different ways to print and format the
stack:

     >>> import traceback
     >>> def another_function():
     ...     lumberstack()
     ...
     >>> def lumberstack():
     ...     traceback.print_stack()
     ...     print(repr(traceback.extract_stack()))
     ...     print(repr(traceback.format_stack()))
     ...
     >>> another_function()
       File "<doctest>", line 10, in <module>
         another_function()
       File "<doctest>", line 3, in another_function
         lumberstack()
       File "<doctest>", line 6, in lumberstack
         traceback.print_stack()
     [('<doctest>', 10, '<module>', 'another_function()'),
      ('<doctest>', 3, 'another_function', 'lumberstack()'),
      ('<doctest>', 7, 'lumberstack', 'print(repr(traceback.extract_stack()))')]
     ['  File "<doctest>", line 10, in <module>\n    another_function()\n',
      '  File "<doctest>", line 3, in another_function\n    lumberstack()\n',
      '  File "<doctest>", line 8, in lumberstack\n    print(repr(traceback.format_stack()))\n']

This last example demonstrates the final few formatting functions:

     >>> import traceback
     >>> traceback.format_list([('spam.py', 3, '<module>', 'spam.eggs()'),
     ...                        ('eggs.py', 42, 'eggs', 'return "bacon"')])
     ['  File "spam.py", line 3, in <module>\n    spam.eggs()\n',
      '  File "eggs.py", line 42, in eggs\n    return "bacon"\n']
     >>> an_error = IndexError('tuple index out of range')
     >>> traceback.format_exception_only(an_error)
     ['IndexError: tuple index out of range\n']


File: python.info,  Node: Examples of Using TracebackException,  Prev: Examples of Using the Module-Level Functions,  Up: traceback — Print or retrieve a stack traceback

5.29.11.6 Examples of Using ‘TracebackException’
................................................

With the helper class, we have more options:

     >>> import sys
     >>> from traceback import TracebackException
     >>>
     >>> def lumberjack():
     ...     bright_side_of_life()
     ...
     >>> def bright_side_of_life():
     ...     t = "bright", "side", "of", "life"
     ...     return t[5]
     ...
     >>> try:
     ...     lumberjack()
     ... except IndexError as e:
     ...     exc = e
     ...
     >>> try:
     ...     try:
     ...         lumberjack()
     ...     except:
     ...         1/0
     ... except Exception as e:
     ...     chained_exc = e
     ...
     >>> # limit works as with the module-level functions
     >>> TracebackException.from_exception(exc, limit=-2).print()
     Traceback (most recent call last):
       File "<python-input-1>", line 6, in lumberjack
         bright_side_of_life()
         ~~~~~~~~~~~~~~~~~~~^^
       File "<python-input-1>", line 10, in bright_side_of_life
         return t[5]
                ~^^^
     IndexError: tuple index out of range

     >>> # capture_locals adds local variables in frames
     >>> TracebackException.from_exception(exc, limit=-2, capture_locals=True).print()
     Traceback (most recent call last):
       File "<python-input-1>", line 6, in lumberjack
         bright_side_of_life()
         ~~~~~~~~~~~~~~~~~~~^^
       File "<python-input-1>", line 10, in bright_side_of_life
         return t[5]
                ~^^^
         t = ("bright", "side", "of", "life")
     IndexError: tuple index out of range

     >>> # The *chain* kwarg to print() controls whether chained
     >>> # exceptions are displayed
     >>> TracebackException.from_exception(chained_exc).print()
     Traceback (most recent call last):
       File "<python-input-19>", line 4, in <module>
         lumberjack()
         ~~~~~~~~~~^^
       File "<python-input-8>", line 7, in lumberjack
         bright_side_of_life()
         ~~~~~~~~~~~~~~~~~~~^^
       File "<python-input-8>", line 11, in bright_side_of_life
         return t[5]
                ~^^^
     IndexError: tuple index out of range

     During handling of the above exception, another exception occurred:

     Traceback (most recent call last):
       File "<python-input-19>", line 6, in <module>
         1/0
         ~^~
     ZeroDivisionError: division by zero

     >>> TracebackException.from_exception(chained_exc).print(chain=False)
     Traceback (most recent call last):
       File "<python-input-19>", line 6, in <module>
         1/0
         ~^~
     ZeroDivisionError: division by zero


File: python.info,  Node: __future__ — Future statement definitions,  Next: gc — Garbage Collector interface,  Prev: traceback — Print or retrieve a stack traceback,  Up: Python Runtime Services

5.29.12 ‘__future__’ — Future statement definitions
---------------------------------------------------

'Source code:' Lib/__future__.py(1)

__________________________________________________________________

Imports of the form ‘from __future__ import feature’ are called *note
future statements: 189.  These are special-cased by the Python compiler
to allow the use of new Python features in modules containing the future
statement before the release in which the feature becomes standard.

While these future statements are given additional special meaning by
the Python compiler, they are still executed like any other import
statement and the ‘__future__’ exists and is handled by the import
system the same way any other Python module would be.  This design
serves three purposes:

   * To avoid confusing existing tools that analyze import statements
     and expect to find the modules they’re importing.

   * To document when incompatible changes were introduced, and when
     they will be — or were — made mandatory.  This is a form of
     executable documentation, and can be inspected programmatically via
     importing ‘__future__’ and examining its contents.

   * To ensure that *note future statements: 189. run under releases
     prior to Python 2.1 at least yield runtime exceptions (the import
     of ‘__future__’ will fail, because there was no module of that name
     prior to 2.1).

* Menu:

* Module Contents: Module Contents<4>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/__future__.py


File: python.info,  Node: Module Contents<4>,  Up: __future__ — Future statement definitions

5.29.12.1 Module Contents
.........................

No feature description will ever be deleted from ‘__future__’.  Since
its introduction in Python 2.1 the following features have found their
way into the language using this mechanism:

feature                       optional in                   mandatory in                  effect
                                                                                          
------------------------------------------------------------------------------------------------------------------------
                                                                                          
 -- Data:                     2.1.0b1                       2.2                           PEP 227(1): 'Statically
          __future__.nested_scopes                                                        Nested Scopes'
                                                                                          
                                                                                          
 -- Data:                     2.2.0a1                       2.3                           PEP 255(2): 'Simple
          __future__.generators                                                           Generators'
                                                                                          
                                                                                          
 -- Data:                     2.2.0a2                       3.0                           PEP 238(3): 'Changing the
          __future__.division                                                             Division Operator'
                                                                                          
                                                                                          
 -- Data:                     2.5.0a1                       3.0                           PEP 328(4): 'Imports:
          __future__.absolute_import                                                      Multi-Line and
                                                                                          Absolute/Relative'
                                                                                          
                                                                                          
 -- Data:                     2.5.0a1                       2.6                           PEP 343(5): 'The “with”
          __future__.with_statement                                                       Statement'
                                                                                          
                                                                                          
 -- Data:                     2.6.0a2                       3.0                           PEP 3105(6): 'Make print a
          __future__.print_function                                                       function'
                                                                                          
                                                                                          
 -- Data:                     2.6.0a2                       3.0                           PEP 3112(7): 'Bytes
          __future__.unicode_literals                                                     literals in Python 3000'
                                                                                          
                                                                                          
 -- Data:                     3.5.0b1                       3.7                           PEP 479(8): 'StopIteration
          __future__.generator_stop                                                       handling inside generators'
                                                                                          
                                                                                          
 -- Data:                     3.7.0b1                       Never (9)                     PEP 563(10): 'Postponed
          __future__.annotations                                                          evaluation of annotations'
                                                                                          

 -- Class: __future__._Feature

     Each statement in ‘__future__.py’ is of the form:

          FeatureName = _Feature(OptionalRelease, MandatoryRelease,
                                 CompilerFlag)

     where, normally, 'OptionalRelease' is less than 'MandatoryRelease',
     and both are 5-tuples of the same form as *note sys.version_info:
     6a3.:

          (PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int
           PY_MINOR_VERSION, # the 1; an int
           PY_MICRO_VERSION, # the 0; an int
           PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string
           PY_RELEASE_SERIAL # the 3; an int
          )

 -- Method: _Feature.getOptionalRelease ()

     'OptionalRelease' records the first release in which the feature
     was accepted.

 -- Method: _Feature.getMandatoryRelease ()

     In the case of a 'MandatoryRelease' that has not yet occurred,
     'MandatoryRelease' predicts the release in which the feature will
     become part of the language.

     Else 'MandatoryRelease' records when the feature became part of the
     language; in releases at or after that, modules no longer need a
     future statement to use the feature in question, but may continue
     to use such imports.

     'MandatoryRelease' may also be ‘None’, meaning that a planned
     feature got dropped or that it is not yet decided.

 -- Attribute: _Feature.compiler_flag

     'CompilerFlag' is the (bitfield) flag that should be passed in the
     fourth argument to the built-in function *note compile(): 192. to
     enable the feature in dynamically compiled code.  This flag is
     stored in the ‘_Feature.compiler_flag’ attribute on *note _Feature:
     2320. instances.

See also
........

*note Future statements: 189.

     How the compiler treats future imports.

PEP 236(11) - Back to the __future__

     The original proposal for the __future__ mechanism.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0227/

   (2) https://peps.python.org/pep-0255/

   (3) https://peps.python.org/pep-0238/

   (4) https://peps.python.org/pep-0328/

   (5) https://peps.python.org/pep-0343/

   (6) https://peps.python.org/pep-3105/

   (7) https://peps.python.org/pep-3112/

   (8) https://peps.python.org/pep-0479/

   (9) ‘from __future__ import annotations’ was previously scheduled to
become mandatory in Python 3.10, but the Python Steering Council twice
decided to delay the change (announcement for Python 3.10
(https://mail.python.org/archives/list/python-dev@python.org/message/CLVXXPQ2T2LQ5MP2Y53VVQFCXYWQJHKZ/);
announcement for Python 3.11
(https://mail.python.org/archives/list/python-dev@python.org/message/VIZEBX5EYMSYIJNDBF6DMUMZOCWHARSO/)).
No final decision has been made yet.  See also PEP 563
(https://peps.python.org/pep-0563/) and PEP 649
(https://peps.python.org/pep-0649/).

   (10) https://peps.python.org/pep-0563/

   (11) https://peps.python.org/pep-0236/


File: python.info,  Node: gc — Garbage Collector interface,  Next: inspect — Inspect live objects,  Prev: __future__ — Future statement definitions,  Up: Python Runtime Services

5.29.13 ‘gc’ — Garbage Collector interface
------------------------------------------

__________________________________________________________________

This module provides an interface to the optional garbage collector.  It
provides the ability to disable the collector, tune the collection
frequency, and set debugging options.  It also provides access to
unreachable objects that the collector found but cannot free.  Since the
collector supplements the reference counting already used in Python, you
can disable the collector if you are sure your program does not create
reference cycles.  Automatic collection can be disabled by calling
‘gc.disable()’.  To debug a leaking program call
‘gc.set_debug(gc.DEBUG_LEAK)’.  Notice that this includes
‘gc.DEBUG_SAVEALL’, causing garbage-collected objects to be saved in
gc.garbage for inspection.

The ‘gc’ module provides the following functions:

 -- Function: gc.enable ()

     Enable automatic garbage collection.

 -- Function: gc.disable ()

     Disable automatic garbage collection.

 -- Function: gc.isenabled ()

     Return ‘True’ if automatic collection is enabled.

 -- Function: gc.collect (generation=2)

     With no arguments, run a full collection.  The optional argument
     'generation' may be an integer specifying which generation to
     collect (from 0 to 2).  A *note ValueError: 202. is raised if the
     generation number is invalid.  The sum of collected objects and
     uncollectable objects is returned.

     The free lists maintained for a number of built-in types are
     cleared whenever a full collection or collection of the highest
     generation (2) is run.  Not all items in some free lists may be
     freed due to the particular implementation, in particular *note
     float: 2f7.

     The effect of calling ‘gc.collect()’ while the interpreter is
     already performing a collection is undefined.

 -- Function: gc.set_debug (flags)

     Set the garbage collection debugging flags.  Debugging information
     will be written to ‘sys.stderr’.  See below for a list of debugging
     flags which can be combined using bit operations to control
     debugging.

 -- Function: gc.get_debug ()

     Return the debugging flags currently set.

 -- Function: gc.get_objects (generation=None)

     Returns a list of all objects tracked by the collector, excluding
     the list returned.  If 'generation' is not ‘None’, return only the
     objects tracked by the collector that are in that generation.

     Changed in version 3.8: New 'generation' parameter.

     Raises an *note auditing event: 1a15. ‘gc.get_objects’ with
     argument ‘generation’.

 -- Function: gc.get_stats ()

     Return a list of three per-generation dictionaries containing
     collection statistics since interpreter start.  The number of keys
     may change in the future, but currently each dictionary will
     contain the following items:

        * ‘collections’ is the number of times this generation was
          collected;

        * ‘collected’ is the total number of objects collected inside
          this generation;

        * ‘uncollectable’ is the total number of objects which were
          found to be uncollectable (and were therefore moved to the
          *note garbage: 1206. list) inside this generation.

     Added in version 3.4.

 -- Function: gc.set_threshold (threshold0[, threshold1[, threshold2]])

     Set the garbage collection thresholds (the collection frequency).
     Setting 'threshold0' to zero disables collection.

     The GC classifies objects into three generations depending on how
     many collection sweeps they have survived.  New objects are placed
     in the youngest generation (generation ‘0’).  If an object survives
     a collection it is moved into the next older generation.  Since
     generation ‘2’ is the oldest generation, objects in that generation
     remain there after a collection.  In order to decide when to run,
     the collector keeps track of the number object allocations and
     deallocations since the last collection.  When the number of
     allocations minus the number of deallocations exceeds 'threshold0',
     collection starts.  Initially only generation ‘0’ is examined.  If
     generation ‘0’ has been examined more than 'threshold1' times since
     generation ‘1’ has been examined, then generation ‘1’ is examined
     as well.  With the third generation, things are a bit more
     complicated, see Collecting the oldest generation(1) for more
     information.

 -- Function: gc.get_count ()

     Return the current collection counts as a tuple of ‘(count0,
     count1, count2)’.

 -- Function: gc.get_threshold ()

     Return the current collection thresholds as a tuple of
     ‘(threshold0, threshold1, threshold2)’.

 -- Function: gc.get_referrers (*objs)

     Return the list of objects that directly refer to any of objs.
     This function will only locate those containers which support
     garbage collection; extension types which do refer to other objects
     but do not support garbage collection will not be found.

     Note that objects which have already been dereferenced, but which
     live in cycles and have not yet been collected by the garbage
     collector can be listed among the resulting referrers.  To get only
     currently live objects, call *note collect(): a47. before calling
     ‘get_referrers()’.

          Warning: Care must be taken when using objects returned by
          ‘get_referrers()’ because some of them could still be under
          construction and hence in a temporarily invalid state.  Avoid
          using ‘get_referrers()’ for any purpose other than debugging.

     Raises an *note auditing event: 1a15. ‘gc.get_referrers’ with
     argument ‘objs’.

 -- Function: gc.get_referents (*objs)

     Return a list of objects directly referred to by any of the
     arguments.  The referents returned are those objects visited by the
     arguments’ C-level *note tp_traverse: 781. methods (if any), and
     may not be all objects actually directly reachable.  ‘tp_traverse’
     methods are supported only by objects that support garbage
     collection, and are only required to visit objects that may be
     involved in a cycle.  So, for example, if an integer is directly
     reachable from an argument, that integer object may or may not
     appear in the result list.

     Raises an *note auditing event: 1a15. ‘gc.get_referents’ with
     argument ‘objs’.

 -- Function: gc.is_tracked (obj)

     Returns ‘True’ if the object is currently tracked by the garbage
     collector, ‘False’ otherwise.  As a general rule, instances of
     atomic types aren’t tracked and instances of non-atomic types
     (containers, user-defined objects…) are.  However, some
     type-specific optimizations can be present in order to suppress the
     garbage collector footprint of simple instances (e.g.  dicts
     containing only atomic keys and values):

          >>> gc.is_tracked(0)
          False
          >>> gc.is_tracked("a")
          False
          >>> gc.is_tracked([])
          True
          >>> gc.is_tracked({})
          False
          >>> gc.is_tracked({"a": 1})
          False
          >>> gc.is_tracked({"a": []})
          True

     Added in version 3.1.

 -- Function: gc.is_finalized (obj)

     Returns ‘True’ if the given object has been finalized by the
     garbage collector, ‘False’ otherwise.

          >>> x = None
          >>> class Lazarus:
          ...     def __del__(self):
          ...         global x
          ...         x = self
          ...
          >>> lazarus = Lazarus()
          >>> gc.is_finalized(lazarus)
          False
          >>> del lazarus
          >>> gc.is_finalized(x)
          True

     Added in version 3.9.

 -- Function: gc.freeze ()

     Freeze all the objects tracked by the garbage collector; move them
     to a permanent generation and ignore them in all the future
     collections.

     If a process will ‘fork()’ without ‘exec()’, avoiding unnecessary
     copy-on-write in child processes will maximize memory sharing and
     reduce overall memory usage.  This requires both avoiding creation
     of freed “holes” in memory pages in the parent process and ensuring
     that GC collections in child processes won’t touch the ‘gc_refs’
     counter of long-lived objects originating in the parent process.
     To accomplish both, call ‘gc.disable()’ early in the parent
     process, ‘gc.freeze()’ right before ‘fork()’, and ‘gc.enable()’
     early in child processes.

     Added in version 3.7.

 -- Function: gc.unfreeze ()

     Unfreeze the objects in the permanent generation, put them back
     into the oldest generation.

     Added in version 3.7.

 -- Function: gc.get_freeze_count ()

     Return the number of objects in the permanent generation.

     Added in version 3.7.

The following variables are provided for read-only access (you can
mutate the values but should not rebind them):

 -- Data: gc.garbage

     A list of objects which the collector found to be unreachable but
     could not be freed (uncollectable objects).  Starting with Python
     3.4, this list should be empty most of the time, except when using
     instances of C extension types with a non-‘NULL’ ‘tp_del’ slot.

     If *note DEBUG_SAVEALL: 46da. is set, then all unreachable objects
     will be added to this list rather than freed.

     Changed in version 3.2: If this list is non-empty at *note
     interpreter shutdown: 14e, a *note ResourceWarning: 244. is
     emitted, which is silent by default.  If *note DEBUG_UNCOLLECTABLE:
     1207. is set, in addition all uncollectable objects are printed.

     Changed in version 3.4: Following PEP 442(2), objects with a *note
     __del__(): 1038. method don’t end up in *note gc.garbage: 1206.
     anymore.

 -- Data: gc.callbacks

     A list of callbacks that will be invoked by the garbage collector
     before and after collection.  The callbacks will be called with two
     arguments, 'phase' and 'info'.

     'phase' can be one of two values:

          “start”: The garbage collection is about to start.

          “stop”: The garbage collection has finished.

     'info' is a dict providing more information for the callback.  The
     following keys are currently defined:

          “generation”: The oldest generation being collected.

          “collected”: When 'phase' is “stop”, the number of objects
          successfully collected.

          “uncollectable”: When 'phase' is “stop”, the number of objects
          that could not be collected and were put in *note garbage:
          1206.

     Applications can add their own callbacks to this list.  The primary
     use cases are:

          Gathering statistics about garbage collection, such as how
          often various generations are collected, and how long the
          collection takes.

          Allowing applications to identify and clear their own
          uncollectable types when they appear in *note garbage: 1206.

     Added in version 3.3.

The following constants are provided for use with *note set_debug():
46d5.:

 -- Data: gc.DEBUG_STATS

     Print statistics during collection.  This information can be useful
     when tuning the collection frequency.

 -- Data: gc.DEBUG_COLLECTABLE

     Print information on collectable objects found.

 -- Data: gc.DEBUG_UNCOLLECTABLE

     Print information of uncollectable objects found (objects which are
     not reachable but cannot be freed by the collector).  These objects
     will be added to the ‘garbage’ list.

     Changed in version 3.2: Also print the contents of the *note
     garbage: 1206. list at *note interpreter shutdown: 14e, if it isn’t
     empty.

 -- Data: gc.DEBUG_SAVEALL

     When set, all unreachable objects found will be appended to
     'garbage' rather than being freed.  This can be useful for
     debugging a leaking program.

 -- Data: gc.DEBUG_LEAK

     The debugging flags necessary for the collector to print
     information about a leaking program (equal to ‘DEBUG_COLLECTABLE |
     DEBUG_UNCOLLECTABLE | DEBUG_SAVEALL’).

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/blob/ff0ef0a54bef26fc507fbf9b7a6009eb7d3f17f5/InternalDocs/garbage_collector.md#collecting-the-oldest-generation

   (2) https://peps.python.org/pep-0442/


File: python.info,  Node: inspect — Inspect live objects,  Next: site — Site-specific configuration hook,  Prev: gc — Garbage Collector interface,  Up: Python Runtime Services

5.29.14 ‘inspect’ — Inspect live objects
----------------------------------------

'Source code:' Lib/inspect.py(1)

__________________________________________________________________

The *note inspect: 7e. module provides several useful functions to help
get information about live objects such as modules, classes, methods,
functions, tracebacks, frame objects, and code objects.  For example, it
can help you examine the contents of a class, retrieve the source code
of a method, extract and format the argument list for a function, or get
all the information you need to display a detailed traceback.

There are four main kinds of services provided by this module: type
checking, getting source code, inspecting classes and functions, and
examining the interpreter stack.

* Menu:

* Types and members::
* Retrieving source code::
* Introspecting callables with the Signature object::
* Classes and functions: Classes and functions<2>.
* The interpreter stack::
* Fetching attributes statically::
* Current State of Generators, Coroutines, and Asynchronous Generators: Current State of Generators Coroutines and Asynchronous Generators.
* Code Objects Bit Flags::
* Buffer flags::
* Command-line interface: Command-line interface<8>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/inspect.py


File: python.info,  Node: Types and members,  Next: Retrieving source code,  Up: inspect — Inspect live objects

5.29.14.1 Types and members
...........................

The *note getmembers(): 1995. function retrieves the members of an
object such as a class or module.  The functions whose names begin with
“is” are mainly provided as convenient choices for the second argument
to ‘getmembers()’.  They also help you determine when you can expect to
find the following special attributes (see *note Import-related
attributes on module objects: 20c3. for module attributes):

Type                  Attribute               Description
                                              
------------------------------------------------------------------------------
                                              
class                 __doc__                 documentation string
                                              
                                              
                      __name__                name with which this class
                                              was defined
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      __module__              name of module in which this
                                              class was defined
                                              
                                              
                      __type_params__         A tuple containing the
                                              *note type parameters: 2b3.
                                              of a generic class
                                              
                                              
method                __doc__                 documentation string
                                              
                                              
                      __name__                name with which this method
                                              was defined
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      __func__                function object containing
                                              implementation of method
                                              
                                              
                      __self__                instance to which this method
                                              is bound, or ‘None’
                                              
                                              
                      __module__              name of module in which this
                                              method was defined
                                              
                                              
function              __doc__                 documentation string
                                              
                                              
                      __name__                name with which this function
                                              was defined
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      __code__                code object containing
                                              compiled function
                                              *note bytecode: 187.
                                              
                                              
                      __defaults__            tuple of any default values
                                              for positional or keyword
                                              parameters
                                              
                                              
                      __kwdefaults__          mapping of any default values
                                              for keyword-only parameters
                                              
                                              
                      __globals__             global namespace in which
                                              this function was defined
                                              
                                              
                      __builtins__            builtins namespace
                                              
                                              
                      __annotations__         mapping of parameters names
                                              to annotations; ‘"return"’
                                              key is reserved for return
                                              annotations.
                                              
                                              
                      __type_params__         A tuple containing the
                                              *note type parameters: 2b3.
                                              of a generic function
                                              
                                              
                      __module__              name of module in which this
                                              function was defined
                                              
                                              
traceback             tb_frame                frame object at this level
                                              
                                              
                      tb_lasti                index of last attempted
                                              instruction in bytecode
                                              
                                              
                      tb_lineno               current line number in Python
                                              source code
                                              
                                              
                      tb_next                 next inner traceback object
                                              (called by this level)
                                              
                                              
frame                 f_back                  next outer frame object (this
                                              frame’s caller)
                                              
                                              
                      f_builtins              builtins namespace seen by
                                              this frame
                                              
                                              
                      f_code                  code object being executed in
                                              this frame
                                              
                                              
                      f_globals               global namespace seen by this
                                              frame
                                              
                                              
                      f_lasti                 index of last attempted
                                              instruction in bytecode
                                              
                                              
                      f_lineno                current line number in Python
                                              source code
                                              
                                              
                      f_locals                local namespace seen by this
                                              frame
                                              
                                              
                      f_trace                 tracing function for this
                                              frame, or ‘None’
                                              
                                              
code                  co_argcount             number of arguments (not
                                              including keyword only
                                              arguments, * or ** args)
                                              
                                              
                      co_code                 string of raw compiled
                                              bytecode
                                              
                                              
                      co_cellvars             tuple of names of cell
                                              variables (referenced by
                                              containing scopes)
                                              
                                              
                      co_consts               tuple of constants used in
                                              the bytecode
                                              
                                              
                      co_filename             name of file in which this
                                              code object was created
                                              
                                              
                      co_firstlineno          number of first line in
                                              Python source code
                                              
                                              
                      co_flags                bitmap of ‘CO_*’ flags, read
                                              more *note here: 20fa.
                                              
                                              
                      co_lnotab               encoded mapping of line
                                              numbers to bytecode indices
                                              
                                              
                      co_freevars             tuple of names of free
                                              variables (referenced via a
                                              function’s closure)
                                              
                                              
                      co_posonlyargcount      number of positional only
                                              arguments
                                              
                                              
                      co_kwonlyargcount       number of keyword only
                                              arguments (not including **
                                              arg)
                                              
                                              
                      co_name                 name with which this code
                                              object was defined
                                              
                                              
                      co_qualname             fully qualified name with
                                              which this code object was
                                              defined
                                              
                                              
                      co_names                tuple of names other than
                                              arguments and function locals
                                              
                                              
                      co_nlocals              number of local variables
                                              
                                              
                      co_stacksize            virtual machine stack space
                                              required
                                              
                                              
                      co_varnames             tuple of names of arguments
                                              and local variables
                                              
                                              
generator             __name__                name
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      gi_frame                frame
                                              
                                              
                      gi_running              is the generator running?
                                              
                                              
                      gi_suspended            is the generator suspended?
                                              
                                              
                      gi_code                 code
                                              
                                              
                      gi_yieldfrom            object being iterated by
                                              ‘yield from’, or ‘None’
                                              
                                              
async generator       __name__                name
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      ag_await                object being awaited on, or
                                              ‘None’
                                              
                                              
                      ag_frame                frame
                                              
                                              
                      ag_running              is the generator running?
                                              
                                              
                      ag_suspended            is the generator suspended?
                                              
                                              
                      ag_code                 code
                                              
                                              
coroutine             __name__                name
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      cr_await                object being awaited on, or
                                              ‘None’
                                              
                                              
                      cr_frame                frame
                                              
                                              
                      cr_running              is the coroutine running?
                                              
                                              
                      cr_suspended            is the coroutine suspended?
                                              
                                              
                      cr_code                 code
                                              
                                              
                      cr_origin               where coroutine was created,
                                              or ‘None’.  See
                                              *note sys.set_coroutine_origin_tracking_depth(): baa.
                                              
                                              
builtin               __doc__                 documentation string
                                              
                                              
                      __name__                original name of this
                                              function or method
                                              
                                              
                      __qualname__            qualified name
                                              
                                              
                      __self__                instance to which a method is
                                              bound, or ‘None’
                                              

Changed in version 3.5: Add ‘__qualname__’ and ‘gi_yieldfrom’ attributes
to generators.

The ‘__name__’ attribute of generators is now set from the function
name, instead of the code name, and it can now be modified.

Changed in version 3.7: Add ‘cr_origin’ attribute to coroutines.

Changed in version 3.10: Add ‘__builtins__’ attribute to functions.

Changed in version 3.11: Add ‘gi_suspended’ attribute to generators.

Changed in version 3.11: Add ‘cr_suspended’ attribute to coroutines.

Changed in version 3.12: Add ‘ag_suspended’ attribute to async
generators.

 -- Function: inspect.getmembers (object[, predicate])

     Return all the members of an object in a list of ‘(name, value)’
     pairs sorted by name.  If the optional 'predicate' argument—which
     will be called with the ‘value’ object of each member—is supplied,
     only members for which the predicate returns a true value are
     included.

          Note: ‘getmembers()’ will only return class attributes defined
          in the metaclass when the argument is a class and those
          attributes have been listed in the metaclass’ custom *note
          __dir__(): 15b7.

 -- Function: inspect.getmembers_static (object[, predicate])

     Return all the members of an object in a list of ‘(name, value)’
     pairs sorted by name without triggering dynamic lookup via the
     descriptor protocol, __getattr__ or __getattribute__.  Optionally,
     only return members that satisfy a given predicate.

          Note: ‘getmembers_static()’ may not be able to retrieve all
          members that getmembers can fetch (like dynamically created
          attributes) and may find members that getmembers can’t (like
          descriptors that raise AttributeError).  It can also return
          descriptor objects instead of instance members in some cases.

     Added in version 3.11.

 -- Function: inspect.getmodulename (path)

     Return the name of the module named by the file 'path', without
     including the names of enclosing packages.  The file extension is
     checked against all of the entries in *note
     importlib.machinery.all_suffixes(): 46e2.  If it matches, the final
     path component is returned with the extension removed.  Otherwise,
     ‘None’ is returned.

     Note that this function 'only' returns a meaningful name for actual
     Python modules - paths that potentially refer to Python packages
     will still return ‘None’.

     Changed in version 3.3: The function is based directly on *note
     importlib: 77.

 -- Function: inspect.ismodule (object)

     Return ‘True’ if the object is a module.

 -- Function: inspect.isclass (object)

     Return ‘True’ if the object is a class, whether built-in or created
     in Python code.

 -- Function: inspect.ismethod (object)

     Return ‘True’ if the object is a bound method written in Python.

 -- Function: inspect.isfunction (object)

     Return ‘True’ if the object is a Python function, which includes
     functions created by a *note lambda: 2908. expression.

 -- Function: inspect.isgeneratorfunction (object)

     Return ‘True’ if the object is a Python generator function.

     Changed in version 3.8: Functions wrapped in *note
     functools.partial(): 417. now return ‘True’ if the wrapped function
     is a Python generator function.

     Changed in version 3.13: Functions wrapped in *note
     functools.partialmethod(): a8a. now return ‘True’ if the wrapped
     function is a Python generator function.

 -- Function: inspect.isgenerator (object)

     Return ‘True’ if the object is a generator.

 -- Function: inspect.iscoroutinefunction (object)

     Return ‘True’ if the object is a *note coroutine function: da1. (a
     function defined with an *note async def: 5d4. syntax), a *note
     functools.partial(): 417. wrapping a coroutine function, or a sync
     function marked with *note markcoroutinefunction(): 493.

     Added in version 3.5.

     Changed in version 3.8: Functions wrapped in *note
     functools.partial(): 417. now return ‘True’ if the wrapped function
     is a *note coroutine function: da1.

     Changed in version 3.12: Sync functions marked with *note
     markcoroutinefunction(): 493. now return ‘True’.

     Changed in version 3.13: Functions wrapped in *note
     functools.partialmethod(): a8a. now return ‘True’ if the wrapped
     function is a *note coroutine function: da1.

 -- Function: inspect.markcoroutinefunction (func)

     Decorator to mark a callable as a *note coroutine function: da1. if
     it would not otherwise be detected by *note iscoroutinefunction():
     2e4.

     This may be of use for sync functions that return a *note
     coroutine: 494, if the function is passed to an API that requires
     *note iscoroutinefunction(): 2e4.

     When possible, using an *note async def: 5d4. function is
     preferred.  Also acceptable is calling the function and testing the
     return with *note iscoroutine(): e48.

     Added in version 3.12.

 -- Function: inspect.iscoroutine (object)

     Return ‘True’ if the object is a *note coroutine: 494. created by
     an *note async def: 5d4. function.

     Added in version 3.5.

 -- Function: inspect.isawaitable (object)

     Return ‘True’ if the object can be used in *note await: 1b9.
     expression.

     Can also be used to distinguish generator-based coroutines from
     regular generators:

          import types

          def gen():
              yield
          @types.coroutine
          def gen_coro():
              yield

          assert not isawaitable(gen())
          assert isawaitable(gen_coro())

     Added in version 3.5.

 -- Function: inspect.isasyncgenfunction (object)

     Return ‘True’ if the object is an *note asynchronous generator:
     21f2. function, for example:

          >>> async def agen():
          ...     yield 1
          ...
          >>> inspect.isasyncgenfunction(agen)
          True

     Added in version 3.6.

     Changed in version 3.8: Functions wrapped in *note
     functools.partial(): 417. now return ‘True’ if the wrapped function
     is an *note asynchronous generator: 21f2. function.

     Changed in version 3.13: Functions wrapped in *note
     functools.partialmethod(): a8a. now return ‘True’ if the wrapped
     function is a *note asynchronous generator: 21f2. function.

 -- Function: inspect.isasyncgen (object)

     Return ‘True’ if the object is an *note asynchronous generator
     iterator: 361f. created by an *note asynchronous generator: 21f2.
     function.

     Added in version 3.6.

 -- Function: inspect.istraceback (object)

     Return ‘True’ if the object is a traceback.

 -- Function: inspect.isframe (object)

     Return ‘True’ if the object is a frame.

 -- Function: inspect.iscode (object)

     Return ‘True’ if the object is a code.

 -- Function: inspect.isbuiltin (object)

     Return ‘True’ if the object is a built-in function or a bound
     built-in method.

 -- Function: inspect.ismethodwrapper (object)

     Return ‘True’ if the type of object is a *note MethodWrapperType:
     64e.

     These are instances of *note MethodWrapperType: 64e, such as *note
     __str__(): 620, *note __eq__(): b13. and *note __repr__(): 61f.

     Added in version 3.11.

 -- Function: inspect.isroutine (object)

     Return ‘True’ if the object is a user-defined or built-in function
     or method.

 -- Function: inspect.isabstract (object)

     Return ‘True’ if the object is an abstract base class.

 -- Function: inspect.ismethoddescriptor (object)

     Return ‘True’ if the object is a method descriptor, but not if
     *note ismethod(): 46e5, *note isclass(): 46e4, *note isfunction():
     46e6. or *note isbuiltin(): 46ec. are true.

     This, for example, is true of ‘int.__add__’.  An object passing
     this test has a *note __get__(): 1537. method, but not a *note
     __set__(): 211b. method or a *note __delete__(): 1713. method.
     Beyond that, the set of attributes varies.  A *note __name__: 10a4.
     attribute is usually sensible, and *note __doc__: 931. often is.

     Methods implemented via descriptors that also pass one of the other
     tests return ‘False’ from the ‘ismethoddescriptor()’ test, simply
     because the other tests promise more – you can, e.g., count on
     having the *note __func__: 1345. attribute (etc) when an object
     passes *note ismethod(): 46e5.

     Changed in version 3.13: This function no longer incorrectly
     reports objects with *note __get__(): 1537. and *note __delete__():
     1713, but not *note __set__(): 211b, as being method descriptors
     (such objects are data descriptors, not method descriptors).

 -- Function: inspect.isdatadescriptor (object)

     Return ‘True’ if the object is a data descriptor.

     Data descriptors have a *note __set__: 211b. or a *note __delete__:
     1713. method.  Examples are properties (defined in Python),
     getsets, and members.  The latter two are defined in C and there
     are more specific tests available for those types, which is robust
     across Python implementations.  Typically, data descriptors will
     also have *note __name__: 10a4. and ‘__doc__’ attributes
     (properties, getsets, and members have both of these attributes),
     but this is not guaranteed.

 -- Function: inspect.isgetsetdescriptor (object)

     Return ‘True’ if the object is a getset descriptor.

     'CPython implementation detail:' getsets are attributes defined in
     extension modules via *note PyGetSetDef: bd7. structures.  For
     Python implementations without such types, this method will always
     return ‘False’.

 -- Function: inspect.ismemberdescriptor (object)

     Return ‘True’ if the object is a member descriptor.

     'CPython implementation detail:' Member descriptors are attributes
     defined in extension modules via *note PyMemberDef: 552.
     structures.  For Python implementations without such types, this
     method will always return ‘False’.


File: python.info,  Node: Retrieving source code,  Next: Introspecting callables with the Signature object,  Prev: Types and members,  Up: inspect — Inspect live objects

5.29.14.2 Retrieving source code
................................

 -- Function: inspect.getdoc (object)

     Get the documentation string for an object, cleaned up with *note
     cleandoc(): 17c5.  If the documentation string for an object is not
     provided and the object is a class, a method, a property or a
     descriptor, retrieve the documentation string from the inheritance
     hierarchy.  Return ‘None’ if the documentation string is invalid or
     missing.

     Changed in version 3.5: Documentation strings are now inherited if
     not overridden.

 -- Function: inspect.getcomments (object)

     Return in a single string any lines of comments immediately
     preceding the object’s source code (for a class, function, or
     method), or at the top of the Python source file (if the object is
     a module).  If the object’s source code is unavailable, return
     ‘None’.  This could happen if the object has been defined in C or
     the interactive shell.

 -- Function: inspect.getfile (object)

     Return the name of the (text or binary) file in which an object was
     defined.  This will fail with a *note TypeError: 2c3. if the object
     is a built-in module, class, or function.

 -- Function: inspect.getmodule (object)

     Try to guess which module an object was defined in.  Return ‘None’
     if the module cannot be determined.

 -- Function: inspect.getsourcefile (object)

     Return the name of the Python source file in which an object was
     defined or ‘None’ if no way can be identified to get the source.
     This will fail with a *note TypeError: 2c3. if the object is a
     built-in module, class, or function.

 -- Function: inspect.getsourcelines (object)

     Return a list of source lines and starting line number for an
     object.  The argument may be a module, class, method, function,
     traceback, frame, or code object.  The source code is returned as a
     list of the lines corresponding to the object and the line number
     indicates where in the original source file the first line of code
     was found.  An *note OSError: 41a. is raised if the source code
     cannot be retrieved.  A *note TypeError: 2c3. is raised if the
     object is a built-in module, class, or function.

     Changed in version 3.3: *note OSError: 41a. is raised instead of
     *note IOError: 1090, now an alias of the former.

 -- Function: inspect.getsource (object)

     Return the text of the source code for an object.  The argument may
     be a module, class, method, function, traceback, frame, or code
     object.  The source code is returned as a single string.  An *note
     OSError: 41a. is raised if the source code cannot be retrieved.  A
     *note TypeError: 2c3. is raised if the object is a built-in module,
     class, or function.

     Changed in version 3.3: *note OSError: 41a. is raised instead of
     *note IOError: 1090, now an alias of the former.

 -- Function: inspect.cleandoc (doc)

     Clean up indentation from docstrings that are indented to line up
     with blocks of code.

     All leading whitespace is removed from the first line.  Any leading
     whitespace that can be uniformly removed from the second line
     onwards is removed.  Empty lines at the beginning and end are
     subsequently removed.  Also, all tabs are expanded to spaces.


File: python.info,  Node: Introspecting callables with the Signature object,  Next: Classes and functions<2>,  Prev: Retrieving source code,  Up: inspect — Inspect live objects

5.29.14.3 Introspecting callables with the Signature object
...........................................................

Added in version 3.3.

The *note Signature: 1cf. object represents the call signature of a
callable object and its return annotation.  To retrieve a ‘Signature’
object, use the ‘signature()’ function.

 -- Function: inspect.signature (callable, *, follow_wrapped=True,
          globals=None, locals=None, eval_str=False)

     Return a *note Signature: 1cf. object for the given 'callable':

          >>> from inspect import signature
          >>> def foo(a, *, b:int, **kwargs):
          ...     pass

          >>> sig = signature(foo)

          >>> str(sig)
          '(a, *, b: int, **kwargs)'

          >>> str(sig.parameters['b'])
          'b: int'

          >>> sig.parameters['b'].annotation
          <class 'int'>

     Accepts a wide range of Python callables, from plain functions and
     classes to *note functools.partial(): 417. objects.

     For objects defined in modules using stringized annotations (‘from
     __future__ import annotations’), ‘signature()’ will attempt to
     automatically un-stringize the annotations using *note
     get_annotations(): 819.  The 'globals', 'locals', and 'eval_str'
     parameters are passed into ‘get_annotations()’ when resolving the
     annotations; see the documentation for ‘get_annotations()’ for
     instructions on how to use these parameters.

     Raises *note ValueError: 202. if no signature can be provided, and
     *note TypeError: 2c3. if that type of object is not supported.
     Also, if the annotations are stringized, and 'eval_str' is not
     false, the ‘eval()’ call(s) to un-stringize the annotations in
     *note get_annotations(): 819. could potentially raise any kind of
     exception.

     A slash(/) in the signature of a function denotes that the
     parameters prior to it are positional-only.  For more info, see
     *note the FAQ entry on positional-only parameters: 232e.

     Changed in version 3.5: The 'follow_wrapped' parameter was added.
     Pass ‘False’ to get a signature of 'callable' specifically
     (‘callable.__wrapped__’ will not be used to unwrap decorated
     callables.)

     Changed in version 3.10: The 'globals', 'locals', and 'eval_str'
     parameters were added.

          Note: Some callables may not be introspectable in certain
          implementations of Python.  For example, in CPython, some
          built-in functions defined in C provide no metadata about
          their arguments.

     'CPython implementation detail:' If the passed object has a
     ‘__signature__’ attribute, we may use it to create the signature.
     The exact semantics are an implementation detail and are subject to
     unannounced changes.  Consult the source code for current
     semantics.

 -- Class: inspect.Signature (parameters=None, *,
          return_annotation=Signature.empty)

     A ‘Signature’ object represents the call signature of a function
     and its return annotation.  For each parameter accepted by the
     function it stores a *note Parameter: 1d0. object in its *note
     parameters: 46f5. collection.

     The optional 'parameters' argument is a sequence of *note
     Parameter: 1d0. objects, which is validated to check that there are
     no parameters with duplicate names, and that the parameters are in
     the right order, i.e.  positional-only first, then
     positional-or-keyword, and that parameters with defaults follow
     parameters without defaults.

     The optional 'return_annotation' argument can be an arbitrary
     Python object.  It represents the “return” annotation of the
     callable.

     ‘Signature’ objects are 'immutable'.  Use *note
     Signature.replace(): 46f6. or *note copy.replace(): 151. to make a
     modified copy.

     Changed in version 3.5: ‘Signature’ objects are now picklable and
     *note hashable: 613.

      -- Attribute: empty

          A special class-level marker to specify absence of a return
          annotation.

      -- Attribute: parameters

          An ordered mapping of parameters’ names to the corresponding
          *note Parameter: 1d0. objects.  Parameters appear in strict
          definition order, including keyword-only parameters.

          Changed in version 3.7: Python only explicitly guaranteed that
          it preserved the declaration order of keyword-only parameters
          as of version 3.7, although in practice this order had always
          been preserved in Python 3.

      -- Attribute: return_annotation

          The “return” annotation for the callable.  If the callable has
          no “return” annotation, this attribute is set to *note
          Signature.empty: 46f7.

      -- Method: bind (*args, **kwargs)

          Create a mapping from positional and keyword arguments to
          parameters.  Returns *note BoundArguments: 10a7. if ‘*args’
          and ‘**kwargs’ match the signature, or raises a *note
          TypeError: 2c3.

      -- Method: bind_partial (*args, **kwargs)

          Works the same way as *note Signature.bind(): 1667, but allows
          the omission of some required arguments (mimics *note
          functools.partial(): 417. behavior.)  Returns *note
          BoundArguments: 10a7, or raises a *note TypeError: 2c3. if the
          passed arguments do not match the signature.

      -- Method: replace (*[, parameters][, return_annotation])

          Create a new ‘Signature’ instance based on the instance
          ‘replace()’ was invoked on.  It is possible to pass different
          'parameters' and/or 'return_annotation' to override the
          corresponding properties of the base signature.  To remove
          ‘return_annotation’ from the copied ‘Signature’, pass in *note
          Signature.empty: 46f7.

               >>> def test(a, b):
               ...     pass
               ...
               >>> sig = signature(test)
               >>> new_sig = sig.replace(return_annotation="new return anno")
               >>> str(new_sig)
               "(a, b) -> 'new return anno'"

          ‘Signature’ objects are also supported by the generic function
          *note copy.replace(): 151.

      -- Method: format (*, max_width=None)

          Create a string representation of the ‘Signature’ object.

          If 'max_width' is passed, the method will attempt to fit the
          signature into lines of at most 'max_width' characters.  If
          the signature is longer than 'max_width', all parameters will
          be on separate lines.

          Added in version 3.13.

      -- Method: classmethod from_callable (obj, *, follow_wrapped=True,
               globals=None, locals=None, eval_str=False)

          Return a ‘Signature’ (or its subclass) object for a given
          callable 'obj'.

          This method simplifies subclassing of ‘Signature’:

               class MySignature(Signature):
                   pass
               sig = MySignature.from_callable(sum)
               assert isinstance(sig, MySignature)

          Its behavior is otherwise identical to that of *note
          signature(): 73b.

          Added in version 3.5.

          Changed in version 3.10: The 'globals', 'locals', and
          'eval_str' parameters were added.

 -- Class: inspect.Parameter (name, kind, *, default=Parameter.empty,
          annotation=Parameter.empty)

     ‘Parameter’ objects are 'immutable'.  Instead of modifying a
     ‘Parameter’ object, you can use *note Parameter.replace(): 46fb. or
     *note copy.replace(): 151. to create a modified copy.

     Changed in version 3.5: Parameter objects are now picklable and
     *note hashable: 613.

      -- Attribute: empty

          A special class-level marker to specify absence of default
          values and annotations.

      -- Attribute: name

          The name of the parameter as a string.  The name must be a
          valid Python identifier.

          'CPython implementation detail:' CPython generates implicit
          parameter names of the form ‘.0’ on the code objects used to
          implement comprehensions and generator expressions.

          Changed in version 3.6: These parameter names are now exposed
          by this module as names like ‘implicit0’.

      -- Attribute: default

          The default value for the parameter.  If the parameter has no
          default value, this attribute is set to *note Parameter.empty:
          46fc.

      -- Attribute: annotation

          The annotation for the parameter.  If the parameter has no
          annotation, this attribute is set to *note Parameter.empty:
          46fc.

      -- Attribute: kind

          Describes how argument values are bound to the parameter.  The
          possible values are accessible via ‘Parameter’ (like
          ‘Parameter.KEYWORD_ONLY’), and support comparison and
          ordering, in the following order:

          Name                         Meaning
                                       
          --------------------------------------------------------------------------------
                                       
          'POSITIONAL_ONLY'            Value must be supplied as a positional argument.
                                       Positional only parameters are those which
                                       appear before a ‘/’ entry (if present) in a
                                       Python function definition.
                                       
                                       
          'POSITIONAL_OR_KEYWORD'      Value may be supplied as either a keyword or
                                       positional argument (this is the standard
                                       binding behaviour for functions implemented in
                                       Python.)
                                       
                                       
          'VAR_POSITIONAL'             A tuple of positional arguments that aren’t
                                       bound to any other parameter.  This corresponds
                                       to a ‘*args’ parameter in a Python function
                                       definition.
                                       
                                       
          'KEYWORD_ONLY'               Value must be supplied as a keyword argument.
                                       Keyword only parameters are those which appear
                                       after a ‘*’ or ‘*args’ entry in a Python
                                       function definition.
                                       
                                       
          'VAR_KEYWORD'                A dict of keyword arguments that aren’t bound to
                                       any other parameter.  This corresponds to a
                                       ‘**kwargs’ parameter in a Python function
                                       definition.
                                       

          Example: print all keyword-only arguments without default
          values:

               >>> def foo(a, b, *, c, d=10):
               ...     pass

               >>> sig = signature(foo)
               >>> for param in sig.parameters.values():
               ...     if (param.kind == param.KEYWORD_ONLY and
               ...                        param.default is param.empty):
               ...         print('Parameter:', param)
               Parameter: c

      -- Attribute: kind.description

          Describes an enum value of *note Parameter.kind: 4700.

          Added in version 3.8.

          Example: print all descriptions of arguments:

               >>> def foo(a, b, *, c, d=10):
               ...     pass

               >>> sig = signature(foo)
               >>> for param in sig.parameters.values():
               ...     print(param.kind.description)
               positional or keyword
               positional or keyword
               keyword-only
               keyword-only

      -- Method: replace (*[, name][, kind][, default][, annotation])

          Create a new ‘Parameter’ instance based on the instance
          replaced was invoked on.  To override a ‘Parameter’ attribute,
          pass the corresponding argument.  To remove a default value
          or/and an annotation from a ‘Parameter’, pass *note
          Parameter.empty: 46fc.

               >>> from inspect import Parameter
               >>> param = Parameter('foo', Parameter.KEYWORD_ONLY, default=42)
               >>> str(param)
               'foo=42'

               >>> str(param.replace()) # Will create a shallow copy of 'param'
               'foo=42'

               >>> str(param.replace(default=Parameter.empty, annotation='spam'))
               "foo: 'spam'"

          ‘Parameter’ objects are also supported by the generic function
          *note copy.replace(): 151.

     Changed in version 3.4: In Python 3.3 ‘Parameter’ objects were
     allowed to have ‘name’ set to ‘None’ if their ‘kind’ was set to
     ‘POSITIONAL_ONLY’.  This is no longer permitted.

 -- Class: inspect.BoundArguments

     Result of a *note Signature.bind(): 1667. or *note
     Signature.bind_partial(): 46f9. call.  Holds the mapping of
     arguments to the function’s parameters.

      -- Attribute: arguments

          A mutable mapping of parameters’ names to arguments’ values.
          Contains only explicitly bound arguments.  Changes in *note
          arguments: 915. will reflect in *note args: 4702. and *note
          kwargs: 4703.

          Should be used in conjunction with *note Signature.parameters:
          46f5. for any argument processing purposes.

               Note: Arguments for which *note Signature.bind(): 1667.
               or *note Signature.bind_partial(): 46f9. relied on a
               default value are skipped.  However, if needed, use *note
               BoundArguments.apply_defaults(): e47. to add them.

          Changed in version 3.9: *note arguments: 915. is now of type
          *note dict: 256.  Formerly, it was of type *note
          collections.OrderedDict: 5de.

      -- Attribute: args

          A tuple of positional arguments values.  Dynamically computed
          from the *note arguments: 915. attribute.

      -- Attribute: kwargs

          A dict of keyword arguments values.  Dynamically computed from
          the *note arguments: 915. attribute.  Arguments that can be
          passed positionally are included in *note args: 4702. instead.

      -- Attribute: signature

          A reference to the parent *note Signature: 1cf. object.

      -- Method: apply_defaults ()

          Set default values for missing arguments.

          For variable-positional arguments (‘*args’) the default is an
          empty tuple.

          For variable-keyword arguments (‘**kwargs’) the default is an
          empty dict.

               >>> def foo(a, b='ham', *args): pass
               >>> ba = inspect.signature(foo).bind('spam')
               >>> ba.apply_defaults()
               >>> ba.arguments
               {'a': 'spam', 'b': 'ham', 'args': ()}

          Added in version 3.5.

     The *note args: 4702. and *note kwargs: 4703. properties can be
     used to invoke functions:

          def test(a, *, b):
              ...

          sig = signature(test)
          ba = sig.bind(10, b=20)
          test(*ba.args, **ba.kwargs)

See also
........

PEP 362(1) - Function Signature Object.

     The detailed specification, implementation details and examples.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0362/


File: python.info,  Node: Classes and functions<2>,  Next: The interpreter stack,  Prev: Introspecting callables with the Signature object,  Up: inspect — Inspect live objects

5.29.14.4 Classes and functions
...............................

 -- Function: inspect.getclasstree (classes, unique=False)

     Arrange the given list of classes into a hierarchy of nested lists.
     Where a nested list appears, it contains classes derived from the
     class whose entry immediately precedes the list.  Each entry is a
     2-tuple containing a class and a tuple of its base classes.  If the
     'unique' argument is true, exactly one entry appears in the
     returned structure for each class in the given list.  Otherwise,
     classes using multiple inheritance and their descendants will
     appear multiple times.

 -- Function: inspect.getfullargspec (func)

     Get the names and default values of a Python function’s parameters.
     A *note named tuple: 651. is returned:

     ‘FullArgSpec(args, varargs, varkw, defaults, kwonlyargs,
     kwonlydefaults, annotations)’

     'args' is a list of the positional parameter names.  'varargs' is
     the name of the ‘*’ parameter or ‘None’ if arbitrary positional
     arguments are not accepted.  'varkw' is the name of the ‘**’
     parameter or ‘None’ if arbitrary keyword arguments are not
     accepted.  'defaults' is an 'n'-tuple of default argument values
     corresponding to the last 'n' positional parameters, or ‘None’ if
     there are no such defaults defined.  'kwonlyargs' is a list of
     keyword-only parameter names in declaration order.
     'kwonlydefaults' is a dictionary mapping parameter names from
     'kwonlyargs' to the default values used if no argument is supplied.
     'annotations' is a dictionary mapping parameter names to
     annotations.  The special key ‘"return"’ is used to report the
     function return value annotation (if any).

     Note that *note signature(): 73b. and *note Signature Object: 46f3.
     provide the recommended API for callable introspection, and support
     additional behaviours (like positional-only arguments) that are
     sometimes encountered in extension module APIs.  This function is
     retained primarily for use in code that needs to maintain
     compatibility with the Python 2 ‘inspect’ module API.

     Changed in version 3.4: This function is now based on *note
     signature(): 73b, but still ignores ‘__wrapped__’ attributes and
     includes the already bound first parameter in the signature output
     for bound methods.

     Changed in version 3.6: This method was previously documented as
     deprecated in favour of *note signature(): 73b. in Python 3.5, but
     that decision has been reversed in order to restore a clearly
     supported standard interface for single-source Python 2/3 code
     migrating away from the legacy ‘getargspec()’ API.

     Changed in version 3.7: Python only explicitly guaranteed that it
     preserved the declaration order of keyword-only parameters as of
     version 3.7, although in practice this order had always been
     preserved in Python 3.

 -- Function: inspect.getargvalues (frame)

     Get information about arguments passed into a particular frame.  A
     *note named tuple: 651. ‘ArgInfo(args, varargs, keywords, locals)’
     is returned.  'args' is a list of the argument names.  'varargs'
     and 'keywords' are the names of the ‘*’ and ‘**’ arguments or
     ‘None’.  'locals' is the locals dictionary of the given frame.

          Note: This function was inadvertently marked as deprecated in
          Python 3.5.

 -- Function: inspect.formatargvalues (args[, varargs, varkw, locals,
          formatarg, formatvarargs, formatvarkw, formatvalue])

     Format a pretty argument spec from the four values returned by
     *note getargvalues(): ef3.  The format* arguments are the
     corresponding optional formatting functions that are called to turn
     names and values into strings.

          Note: This function was inadvertently marked as deprecated in
          Python 3.5.

 -- Function: inspect.getmro (cls)

     Return a tuple of class cls’s base classes, including cls, in
     method resolution order.  No class appears more than once in this
     tuple.  Note that the method resolution order depends on cls’s
     type.  Unless a very peculiar user-defined metatype is in use, cls
     will be the first element of the tuple.

 -- Function: inspect.getcallargs (func, /, *args, **kwds)

     Bind the 'args' and 'kwds' to the argument names of the Python
     function or method 'func', as if it was called with them.  For
     bound methods, bind also the first argument (typically named
     ‘self’) to the associated instance.  A dict is returned, mapping
     the argument names (including the names of the ‘*’ and ‘**’
     arguments, if any) to their values from 'args' and 'kwds'.  In case
     of invoking 'func' incorrectly, i.e.  whenever ‘func(*args,
     **kwds)’ would raise an exception because of incompatible
     signature, an exception of the same type and the same or similar
     message is raised.  For example:

          >>> from inspect import getcallargs
          >>> def f(a, b=1, *pos, **named):
          ...     pass
          ...
          >>> getcallargs(f, 1, 2, 3) == {'a': 1, 'named': {}, 'b': 2, 'pos': (3,)}
          True
          >>> getcallargs(f, a=2, x=4) == {'a': 2, 'named': {'x': 4}, 'b': 1, 'pos': ()}
          True
          >>> getcallargs(f)
          Traceback (most recent call last):
          ...
          TypeError: f() missing 1 required positional argument: 'a'

     Added in version 3.2.

     Deprecated since version 3.5: Use *note Signature.bind(): 1667. and
     *note Signature.bind_partial(): 46f9. instead.

 -- Function: inspect.getclosurevars (func)

     Get the mapping of external name references in a Python function or
     method 'func' to their current values.  A *note named tuple: 651.
     ‘ClosureVars(nonlocals, globals, builtins, unbound)’ is returned.
     'nonlocals' maps referenced names to lexical closure variables,
     'globals' to the function’s module globals and 'builtins' to the
     builtins visible from the function body.  'unbound' is the set of
     names referenced in the function that could not be resolved at all
     given the current module globals and builtins.

     *note TypeError: 2c3. is raised if 'func' is not a Python function
     or method.

     Added in version 3.3.

 -- Function: inspect.unwrap (func, *, stop=None)

     Get the object wrapped by 'func'.  It follows the chain of
     ‘__wrapped__’ attributes returning the last object in the chain.

     'stop' is an optional callback accepting an object in the wrapper
     chain as its sole argument that allows the unwrapping to be
     terminated early if the callback returns a true value.  If the
     callback never returns a true value, the last object in the chain
     is returned as usual.  For example, *note signature(): 73b. uses
     this to stop unwrapping if any object in the chain has a
     ‘__signature__’ attribute defined.

     *note ValueError: 202. is raised if a cycle is encountered.

     Added in version 3.4.

 -- Function: inspect.get_annotations (obj, *, globals=None,
          locals=None, eval_str=False)

     Compute the annotations dict for an object.

     ‘obj’ may be a callable, class, or module.  Passing in an object of
     any other type raises *note TypeError: 2c3.

     Returns a dict.  ‘get_annotations()’ returns a new dict every time
     it’s called; calling it twice on the same object will return two
     different but equivalent dicts.

     This function handles several details for you:

        * If ‘eval_str’ is true, values of type ‘str’ will be
          un-stringized using *note eval(): 180.  This is intended for
          use with stringized annotations (‘from __future__ import
          annotations’).

        * If ‘obj’ doesn’t have an annotations dict, returns an empty
          dict.  (Functions and methods always have an annotations dict;
          classes, modules, and other types of callables may not.)

        * Ignores inherited annotations on classes.  If a class doesn’t
          have its own annotations dict, returns an empty dict.

        * All accesses to object members and dict values are done using
          ‘getattr()’ and ‘dict.get()’ for safety.

        * Always, always, always returns a freshly created dict.

     ‘eval_str’ controls whether or not values of type ‘str’ are
     replaced with the result of calling *note eval(): 180. on those
     values:

        * If eval_str is true, *note eval(): 180. is called on values of
          type ‘str’.  (Note that ‘get_annotations’ doesn’t catch
          exceptions; if ‘eval()’ raises an exception, it will unwind
          the stack past the ‘get_annotations’ call.)

        * If eval_str is false (the default), values of type ‘str’ are
          unchanged.

     ‘globals’ and ‘locals’ are passed in to *note eval(): 180.; see the
     documentation for ‘eval()’ for more information.  If ‘globals’ or
     ‘locals’ is ‘None’, this function may replace that value with a
     context-specific default, contingent on ‘type(obj)’:

        * If ‘obj’ is a module, ‘globals’ defaults to ‘obj.__dict__’.

        * If ‘obj’ is a class, ‘globals’ defaults to
          ‘sys.modules[obj.__module__].__dict__’ and ‘locals’ defaults
          to the ‘obj’ class namespace.

        * If ‘obj’ is a callable, ‘globals’ defaults to *note
          obj.__globals__: 131b, although if ‘obj’ is a wrapped function
          (using *note functools.update_wrapper(): 105d.) it is first
          unwrapped.

     Calling ‘get_annotations’ is best practice for accessing the
     annotations dict of any object.  See *note Annotations Best
     Practices: 7dd. for more information on annotations best practices.

     Added in version 3.10.


File: python.info,  Node: The interpreter stack,  Next: Fetching attributes statically,  Prev: Classes and functions<2>,  Up: inspect — Inspect live objects

5.29.14.5 The interpreter stack
...............................

Some of the following functions return *note FrameInfo: 64f. objects.
For backwards compatibility these objects allow tuple-like operations on
all attributes except ‘positions’.  This behavior is considered
deprecated and may be removed in the future.

 -- Class: inspect.FrameInfo

      -- Attribute: frame

          The *note frame object: 6e3. that the record corresponds to.

      -- Attribute: filename

          The file name associated with the code being executed by the
          frame this record corresponds to.

      -- Attribute: lineno

          The line number of the current line associated with the code
          being executed by the frame this record corresponds to.

      -- Attribute: function

          The function name that is being executed by the frame this
          record corresponds to.

      -- Attribute: code_context

          A list of lines of context from the source code that’s being
          executed by the frame this record corresponds to.

      -- Attribute: index

          The index of the current line being executed in the *note
          code_context: 470f. list.

      -- Attribute: positions

          A *note dis.Positions: 4712. object containing the start line
          number, end line number, start column offset, and end column
          offset associated with the instruction being executed by the
          frame this record corresponds to.

     Changed in version 3.5: Return a *note named tuple: 651. instead of
     a *note tuple: 373.

     Changed in version 3.11: ‘FrameInfo’ is now a class instance (that
     is backwards compatible with the previous *note named tuple: 651.).

 -- Class: inspect.Traceback

      -- Attribute: filename

          The file name associated with the code being executed by the
          frame this traceback corresponds to.

      -- Attribute: lineno

          The line number of the current line associated with the code
          being executed by the frame this traceback corresponds to.

      -- Attribute: function

          The function name that is being executed by the frame this
          traceback corresponds to.

      -- Attribute: code_context

          A list of lines of context from the source code that’s being
          executed by the frame this traceback corresponds to.

      -- Attribute: index

          The index of the current line being executed in the *note
          code_context: 4716. list.

      -- Attribute: positions

          A *note dis.Positions: 4712. object containing the start line
          number, end line number, start column offset, and end column
          offset associated with the instruction being executed by the
          frame this traceback corresponds to.

     Changed in version 3.11: ‘Traceback’ is now a class instance (that
     is backwards compatible with the previous *note named tuple: 651.).

     Note: Keeping references to frame objects, as found in the first
     element of the frame records these functions return, can cause your
     program to create reference cycles.  Once a reference cycle has
     been created, the lifespan of all objects which can be accessed
     from the objects which form the cycle can become much longer even
     if Python’s optional cycle detector is enabled.  If such cycles
     must be created, it is important to ensure they are explicitly
     broken to avoid the delayed destruction of objects and increased
     memory consumption which occurs.

     Though the cycle detector will catch these, destruction of the
     frames (and local variables) can be made deterministic by removing
     the cycle in a *note finally: 9d5. clause.  This is also important
     if the cycle detector was disabled when Python was compiled or
     using *note gc.disable(): 46d3.  For example:

          def handle_stackframe_without_leak():
              frame = inspect.currentframe()
              try:
                  # do something with the frame
              finally:
                  del frame

     If you want to keep the frame around (for example to print a
     traceback later), you can also break reference cycles by using the
     *note frame.clear(): 280. method.

The optional 'context' argument supported by most of these functions
specifies the number of lines of context to return, which are centered
around the current line.

 -- Function: inspect.getframeinfo (frame, context=1)

     Get information about a frame or traceback object.  A *note
     Traceback: 650. object is returned.

     Changed in version 3.11: A *note Traceback: 650. object is returned
     instead of a named tuple.

 -- Function: inspect.getouterframes (frame, context=1)

     Get a list of *note FrameInfo: 64f. objects for a frame and all
     outer frames.  These frames represent the calls that lead to the
     creation of 'frame'.  The first entry in the returned list
     represents 'frame'; the last entry represents the outermost call on
     'frame'’s stack.

     Changed in version 3.5: A list of *note named tuples: 651.
     ‘FrameInfo(frame, filename, lineno, function, code_context, index)’
     is returned.

     Changed in version 3.11: A list of *note FrameInfo: 64f. objects is
     returned.

 -- Function: inspect.getinnerframes (traceback, context=1)

     Get a list of *note FrameInfo: 64f. objects for a traceback’s frame
     and all inner frames.  These frames represent calls made as a
     consequence of 'frame'.  The first entry in the list represents
     'traceback'; the last entry represents where the exception was
     raised.

     Changed in version 3.5: A list of *note named tuples: 651.
     ‘FrameInfo(frame, filename, lineno, function, code_context, index)’
     is returned.

     Changed in version 3.11: A list of *note FrameInfo: 64f. objects is
     returned.

 -- Function: inspect.currentframe ()

     Return the frame object for the caller’s stack frame.

     'CPython implementation detail:' This function relies on Python
     stack frame support in the interpreter, which isn’t guaranteed to
     exist in all implementations of Python.  If running in an
     implementation without Python stack frame support this function
     returns ‘None’.

 -- Function: inspect.stack (context=1)

     Return a list of *note FrameInfo: 64f. objects for the caller’s
     stack.  The first entry in the returned list represents the caller;
     the last entry represents the outermost call on the stack.

     Changed in version 3.5: A list of *note named tuples: 651.
     ‘FrameInfo(frame, filename, lineno, function, code_context, index)’
     is returned.

     Changed in version 3.11: A list of *note FrameInfo: 64f. objects is
     returned.

 -- Function: inspect.trace (context=1)

     Return a list of *note FrameInfo: 64f. objects for the stack
     between the current frame and the frame in which an exception
     currently being handled was raised in.  The first entry in the list
     represents the caller; the last entry represents where the
     exception was raised.

     Changed in version 3.5: A list of *note named tuples: 651.
     ‘FrameInfo(frame, filename, lineno, function, code_context, index)’
     is returned.

     Changed in version 3.11: A list of *note FrameInfo: 64f. objects is
     returned.


File: python.info,  Node: Fetching attributes statically,  Next: Current State of Generators Coroutines and Asynchronous Generators,  Prev: The interpreter stack,  Up: inspect — Inspect live objects

5.29.14.6 Fetching attributes statically
........................................

Both *note getattr(): bf0. and *note hasattr(): 4d5. can trigger code
execution when fetching or checking for the existence of attributes.
Descriptors, like properties, will be invoked and *note __getattr__():
4d6. and *note __getattribute__(): bf1. may be called.

For cases where you want passive introspection, like documentation
tools, this can be inconvenient.  *note getattr_static(): 497. has the
same signature as *note getattr(): bf0. but avoids executing code when
it fetches attributes.

 -- Function: inspect.getattr_static (obj, attr, default=None)

     Retrieve attributes without triggering dynamic lookup via the
     descriptor protocol, *note __getattr__(): 4d6. or *note
     __getattribute__(): bf1.

     Note: this function may not be able to retrieve all attributes that
     getattr can fetch (like dynamically created attributes) and may
     find attributes that getattr can’t (like descriptors that raise
     AttributeError).  It can also return descriptors objects instead of
     instance members.

     If the instance *note __dict__: 55e. is shadowed by another member
     (for example a property) then this function will be unable to find
     instance members.

     Added in version 3.2.

*note getattr_static(): 497. does not resolve descriptors, for example
slot descriptors or getset descriptors on objects implemented in C. The
descriptor object is returned instead of the underlying attribute.

You can handle these with code like the following.  Note that for
arbitrary getset descriptors invoking these may trigger code execution:

     # example code for resolving the builtin descriptor types
     class _foo:
         __slots__ = ['foo']

     slot_descriptor = type(_foo.foo)
     getset_descriptor = type(type(open(__file__)).name)
     wrapper_descriptor = type(str.__dict__['__add__'])
     descriptor_types = (slot_descriptor, getset_descriptor, wrapper_descriptor)

     result = getattr_static(some_object, 'foo')
     if type(result) in descriptor_types:
         try:
             result = result.__get__()
         except AttributeError:
             # descriptors can raise AttributeError to
             # indicate there is no underlying value
             # in which case the descriptor itself will
             # have to do
             pass


File: python.info,  Node: Current State of Generators Coroutines and Asynchronous Generators,  Next: Code Objects Bit Flags,  Prev: Fetching attributes statically,  Up: inspect — Inspect live objects

5.29.14.7 Current State of Generators, Coroutines, and Asynchronous Generators
..............................................................................

When implementing coroutine schedulers and for other advanced uses of
generators, it is useful to determine whether a generator is currently
executing, is waiting to start or resume or execution, or has already
terminated.  *note getgeneratorstate(): 127c. allows the current state
of a generator to be determined easily.

 -- Function: inspect.getgeneratorstate (generator)

     Get current state of a generator-iterator.

     Possible states are:

        * GEN_CREATED: Waiting to start execution.

        * GEN_RUNNING: Currently being executed by the interpreter.

        * GEN_SUSPENDED: Currently suspended at a yield expression.

        * GEN_CLOSED: Execution has completed.

     Added in version 3.2.

 -- Function: inspect.getcoroutinestate (coroutine)

     Get current state of a coroutine object.  The function is intended
     to be used with coroutine objects created by *note async def: 5d4.
     functions, but will accept any coroutine-like object that has
     ‘cr_running’ and ‘cr_frame’ attributes.

     Possible states are:

        * CORO_CREATED: Waiting to start execution.

        * CORO_RUNNING: Currently being executed by the interpreter.

        * CORO_SUSPENDED: Currently suspended at an await expression.

        * CORO_CLOSED: Execution has completed.

     Added in version 3.5.

 -- Function: inspect.getasyncgenstate (agen)

     Get current state of an asynchronous generator object.  The
     function is intended to be used with asynchronous iterator objects
     created by *note async def: 5d4. functions which use the *note
     yield: 9d8. statement, but will accept any asynchronous
     generator-like object that has ‘ag_running’ and ‘ag_frame’
     attributes.

     Possible states are:

        * AGEN_CREATED: Waiting to start execution.

        * AGEN_RUNNING: Currently being executed by the interpreter.

        * AGEN_SUSPENDED: Currently suspended at a yield expression.

        * AGEN_CLOSED: Execution has completed.

     Added in version 3.12.

The current internal state of the generator can also be queried.  This
is mostly useful for testing purposes, to ensure that internal state is
being updated as expected:

 -- Function: inspect.getgeneratorlocals (generator)

     Get the mapping of live local variables in 'generator' to their
     current values.  A dictionary is returned that maps from variable
     names to values.  This is the equivalent of calling *note locals():
     141. in the body of the generator, and all the same caveats apply.

     If 'generator' is a *note generator: 109f. with no currently
     associated frame, then an empty dictionary is returned.  *note
     TypeError: 2c3. is raised if 'generator' is not a Python generator
     object.

     'CPython implementation detail:' This function relies on the
     generator exposing a Python stack frame for introspection, which
     isn’t guaranteed to be the case in all implementations of Python.
     In such cases, this function will always return an empty
     dictionary.

     Added in version 3.3.

 -- Function: inspect.getcoroutinelocals (coroutine)

     This function is analogous to *note getgeneratorlocals(): 111a, but
     works for coroutine objects created by *note async def: 5d4.
     functions.

     Added in version 3.5.

 -- Function: inspect.getasyncgenlocals (agen)

     This function is analogous to *note getgeneratorlocals(): 111a, but
     works for asynchronous generator objects created by *note async
     def: 5d4. functions which use the *note yield: 9d8. statement.

     Added in version 3.12.


File: python.info,  Node: Code Objects Bit Flags,  Next: Buffer flags,  Prev: Current State of Generators Coroutines and Asynchronous Generators,  Up: inspect — Inspect live objects

5.29.14.8 Code Objects Bit Flags
................................

Python code objects have a *note co_flags: 20f9. attribute, which is a
bitmap of the following flags:

 -- Data: inspect.CO_OPTIMIZED

     The code object is optimized, using fast locals.

 -- Data: inspect.CO_NEWLOCALS

     If set, a new dict will be created for the frame’s *note f_locals:
     182. when the code object is executed.

 -- Data: inspect.CO_VARARGS

     The code object has a variable positional parameter (‘*args’-like).

 -- Data: inspect.CO_VARKEYWORDS

     The code object has a variable keyword parameter (‘**kwargs’-like).

 -- Data: inspect.CO_NESTED

     The flag is set when the code object is a nested function.

 -- Data: inspect.CO_GENERATOR

     The flag is set when the code object is a generator function, i.e.
     a generator object is returned when the code object is executed.

 -- Data: inspect.CO_COROUTINE

     The flag is set when the code object is a coroutine function.  When
     the code object is executed it returns a coroutine object.  See PEP
     492(1) for more details.

     Added in version 3.5.

 -- Data: inspect.CO_ITERABLE_COROUTINE

     The flag is used to transform generators into generator-based
     coroutines.  Generator objects with this flag can be used in
     ‘await’ expression, and can ‘yield from’ coroutine objects.  See
     PEP 492(2) for more details.

     Added in version 3.5.

 -- Data: inspect.CO_ASYNC_GENERATOR

     The flag is set when the code object is an asynchronous generator
     function.  When the code object is executed it returns an
     asynchronous generator object.  See PEP 525(3) for more details.

     Added in version 3.6.

     Note: The flags are specific to CPython, and may not be defined in
     other Python implementations.  Furthermore, the flags are an
     implementation detail, and can be removed or deprecated in future
     Python releases.  It’s recommended to use public APIs from the
     *note inspect: 7e. module for any introspection needs.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0492/

   (2) https://peps.python.org/pep-0492/

   (3) https://peps.python.org/pep-0525/


File: python.info,  Node: Buffer flags,  Next: Command-line interface<8>,  Prev: Code Objects Bit Flags,  Up: inspect — Inspect live objects

5.29.14.9 Buffer flags
......................

 -- Class: inspect.BufferFlags

     This is an *note enum.IntFlag: cc1. that represents the flags that
     can be passed to the *note __buffer__(): 462. method of objects
     implementing the *note buffer protocol: 2e8.

     The meaning of the flags is explained at *note Buffer request
     types: 4726.

      -- Attribute: SIMPLE

      -- Attribute: WRITABLE

      -- Attribute: FORMAT

      -- Attribute: ND

      -- Attribute: STRIDES

      -- Attribute: C_CONTIGUOUS

      -- Attribute: F_CONTIGUOUS

      -- Attribute: ANY_CONTIGUOUS

      -- Attribute: INDIRECT

      -- Attribute: CONTIG

      -- Attribute: CONTIG_RO

      -- Attribute: STRIDED

      -- Attribute: STRIDED_RO

      -- Attribute: RECORDS

      -- Attribute: RECORDS_RO

      -- Attribute: FULL

      -- Attribute: FULL_RO

      -- Attribute: READ

      -- Attribute: WRITE

     Added in version 3.12.


File: python.info,  Node: Command-line interface<8>,  Prev: Buffer flags,  Up: inspect — Inspect live objects

5.29.14.10 Command-line interface
.................................

The *note inspect: 7e. module also provides a basic introspection
capability from the command line.

By default, accepts the name of a module and prints the source of that
module.  A class or function within the module can be printed instead by
appended a colon and the qualified name of the target object.

 -- Option: --details

     Print information about the specified object rather than the source
     code


File: python.info,  Node: site — Site-specific configuration hook,  Prev: inspect — Inspect live objects,  Up: Python Runtime Services

5.29.15 ‘site’ — Site-specific configuration hook
-------------------------------------------------

'Source code:' Lib/site.py(1)

__________________________________________________________________

'This module is automatically imported during initialization.'  The
automatic import can be suppressed using the interpreter’s *note -S:
11ec. option.

Importing this module normally appends site-specific paths to the module
search path and adds *note callables: 2341, including *note help(): 8e0.
to the built-in namespace.  However, Python startup option *note -S:
11ec. blocks this and this module can be safely imported with no
automatic modifications to the module search path or additions to the
builtins.  To explicitly trigger the usual site-specific additions, call
the *note main(): 1ede. function.

Changed in version 3.3: Importing the module used to trigger paths
manipulation even when using *note -S: 11ec.

It starts by constructing up to four directories from a head and a tail
part.  For the head part, it uses ‘sys.prefix’ and ‘sys.exec_prefix’;
empty heads are skipped.  For the tail part, it uses the empty string
and then ‘lib/site-packages’ (on Windows) or
‘lib/python`X.Y[t]'/site-packages’ (on Unix and macOS). (The optional
suffix “t” indicates the *note free threading: 15b3. build, and is
appended if ‘"t"’ is present in the *note sys.abiflags: a72. constant.)
For each of the distinct head-tail combinations, it sees if it refers to
an existing directory, and if so, adds it to ‘sys.path’ and also
inspects the newly added path for configuration files.

Changed in version 3.5: Support for the “site-python” directory has been
removed.

Changed in version 3.13: On Unix, *note Free threading: 15b3. Python
installations are identified by the “t” suffix in the version-specific
directory name, such as ‘lib/python3.13t/’.

If a file named “pyvenv.cfg” exists one directory above sys.executable,
sys.prefix and sys.exec_prefix are set to that directory and it is also
checked for site-packages (sys.base_prefix and sys.base_exec_prefix will
always be the “real” prefixes of the Python installation).  If
“pyvenv.cfg” (a bootstrap configuration file) contains the key
“include-system-site-packages” set to anything other than “true”
(case-insensitive), the system-level prefixes will not be searched for
site-packages; otherwise they will.

A path configuration file is a file whose name has the form ‘`name'.pth’
and exists in one of the four directories mentioned above; its contents
are additional items (one per line) to be added to ‘sys.path’.
Non-existing items are never added to ‘sys.path’, and no check is made
that the item refers to a directory rather than a file.  No item is
added to ‘sys.path’ more than once.  Blank lines and lines beginning
with ‘#’ are skipped.  Lines starting with ‘import’ (followed by space
or tab) are executed.

     Note: An executable line in a ‘.pth’ file is run at every Python
     startup, regardless of whether a particular module is actually
     going to be used.  Its impact should thus be kept to a minimum.
     The primary intended purpose of executable lines is to make the
     corresponding module(s) importable (load 3rd-party import hooks,
     adjust ‘PATH’ etc).  Any other initialization is supposed to be
     done upon a module’s actual import, if and when it happens.
     Limiting a code chunk to a single line is a deliberate measure to
     discourage putting anything more complex here.

Changed in version 3.13: The ‘.pth’ files are now decoded by UTF-8 at
first and then by the *note locale encoding: 242. if it fails.

For example, suppose ‘sys.prefix’ and ‘sys.exec_prefix’ are set to
‘/usr/local’.  The Python X.Y library is then installed in
‘/usr/local/lib/python`X.Y'’.  Suppose this has a subdirectory
‘/usr/local/lib/python`X.Y'/site-packages’ with three subsubdirectories,
‘foo’, ‘bar’ and ‘spam’, and two path configuration files, ‘foo.pth’ and
‘bar.pth’.  Assume ‘foo.pth’ contains the following:

     # foo package configuration

     foo
     bar
     bletch

and ‘bar.pth’ contains:

     # bar package configuration

     bar

Then the following version-specific directories are added to ‘sys.path’,
in this order:

     /usr/local/lib/pythonX.Y/site-packages/bar
     /usr/local/lib/pythonX.Y/site-packages/foo

Note that ‘bletch’ is omitted because it doesn’t exist; the ‘bar’
directory precedes the ‘foo’ directory because ‘bar.pth’ comes
alphabetically before ‘foo.pth’; and ‘spam’ is omitted because it is not
mentioned in either path configuration file.

* Menu:

* sitecustomize::
* usercustomize::
* Readline configuration::
* Module contents: Module contents<6>.
* Command-line interface: Command-line interface<9>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/site.py


File: python.info,  Node: sitecustomize,  Next: usercustomize,  Up: site — Site-specific configuration hook

5.29.15.1 ‘sitecustomize’
.........................

After these path manipulations, an attempt is made to import a module
named ‘sitecustomize’, which can perform arbitrary site-specific
customizations.  It is typically created by a system administrator in
the site-packages directory.  If this import fails with an *note
ImportError: 41c. or its subclass exception, and the exception’s *note
name: 2442. attribute equals ‘'sitecustomize'’, it is silently ignored.
If Python is started without output streams available, as with
‘pythonw.exe’ on Windows (which is used by default to start IDLE),
attempted output from ‘sitecustomize’ is ignored.  Any other exception
causes a silent and perhaps mysterious failure of the process.


File: python.info,  Node: usercustomize,  Next: Readline configuration,  Prev: sitecustomize,  Up: site — Site-specific configuration hook

5.29.15.2 ‘usercustomize’
.........................

After this, an attempt is made to import a module named ‘usercustomize’,
which can perform arbitrary user-specific customizations, if *note
ENABLE_USER_SITE: 473f. is true.  This file is intended to be created in
the user site-packages directory (see below), which is part of
‘sys.path’ unless disabled by *note -s: 13db.  If this import fails with
an *note ImportError: 41c. or its subclass exception, and the
exception’s *note name: 2442. attribute equals ‘'usercustomize'’, it is
silently ignored.

Note that for some non-Unix systems, ‘sys.prefix’ and ‘sys.exec_prefix’
are empty, and the path manipulations are skipped; however the import of
*note sitecustomize: c8. and ‘usercustomize’ is still attempted.


File: python.info,  Node: Readline configuration,  Next: Module contents<6>,  Prev: usercustomize,  Up: site — Site-specific configuration hook

5.29.15.3 Readline configuration
................................

On systems that support *note readline: ba, this module will also import
and configure the *note rlcompleter: bd. module, if Python is started in
*note interactive mode: 1001. and without the *note -S: 11ec. option.
The default behavior is to enable tab completion and to use
‘~/.python_history’ as the history save file.  To disable it, delete (or
override) the *note sys.__interactivehook__: 1002. attribute in your
*note sitecustomize: c8. or *note usercustomize: 10e. module or your
*note PYTHONSTARTUP: 1003. file.

Changed in version 3.4: Activation of rlcompleter and history was made
automatic.


File: python.info,  Node: Module contents<6>,  Next: Command-line interface<9>,  Prev: Readline configuration,  Up: site — Site-specific configuration hook

5.29.15.4 Module contents
.........................

 -- Data: site.PREFIXES

     A list of prefixes for site-packages directories.

 -- Data: site.ENABLE_USER_SITE

     Flag showing the status of the user site-packages directory.
     ‘True’ means that it is enabled and was added to ‘sys.path’.
     ‘False’ means that it was disabled by user request (with *note -s:
     13db. or *note PYTHONNOUSERSITE: 13dc.).  ‘None’ means it was
     disabled for security reasons (mismatch between user or group id
     and effective id) or by an administrator.

 -- Data: site.USER_SITE

     Path to the user site-packages for the running Python.  Can be
     ‘None’ if *note getusersitepackages(): 1286. hasn’t been called
     yet.  Default value is ‘~/.local/lib/python`X.Y'[t]/site-packages’
     for UNIX and non-framework macOS builds,
     ‘~/Library/Python/`X.Y'/lib/python/site-packages’ for macOS
     framework builds, and ‘`%APPDATA%'\Python\Python`XY'\site-packages’
     on Windows.  The optional “t” indicates the free-threaded build.
     This directory is a site directory, which means that ‘.pth’ files
     in it will be processed.

 -- Data: site.USER_BASE

     Path to the base directory for the user site-packages.  Can be
     ‘None’ if *note getuserbase(): 1285. hasn’t been called yet.
     Default value is ‘~/.local’ for UNIX and macOS non-framework
     builds, ‘~/Library/Python/`X.Y'’ for macOS framework builds, and
     ‘`%APPDATA%'\Python’ for Windows.  This value is used to compute
     the installation directories for scripts, data files, Python
     modules, etc.  for the *note user installation scheme: 1eef.  See
     also *note PYTHONUSERBASE: 13da.

 -- Function: site.main ()

     Adds all the standard site-specific directories to the module
     search path.  This function is called automatically when this
     module is imported, unless the Python interpreter was started with
     the *note -S: 11ec. flag.

     Changed in version 3.3: This function used to be called
     unconditionally.

 -- Function: site.addsitedir (sitedir, known_paths=None)

     Add a directory to sys.path and process its ‘.pth’ files.
     Typically used in *note sitecustomize: c8. or *note usercustomize:
     10e. (see above).

 -- Function: site.getsitepackages ()

     Return a list containing all global site-packages directories.

     Added in version 3.2.

 -- Function: site.getuserbase ()

     Return the path of the user base directory, *note USER_BASE: 1366.
     If it is not initialized yet, this function will also set it,
     respecting *note PYTHONUSERBASE: 13da.

     Added in version 3.2.

 -- Function: site.getusersitepackages ()

     Return the path of the user-specific site-packages directory, *note
     USER_SITE: 1edd.  If it is not initialized yet, this function will
     also set it, respecting *note USER_BASE: 1366.  To determine if the
     user-specific site-packages was added to ‘sys.path’ *note
     ENABLE_USER_SITE: 473f. should be used.

     Added in version 3.2.


File: python.info,  Node: Command-line interface<9>,  Prev: Module contents<6>,  Up: site — Site-specific configuration hook

5.29.15.5 Command-line interface
................................

The ‘site’ module also provides a way to get the user directories from
the command line:

     $ python -m site --user-site
     /home/user/.local/lib/python3.11/site-packages

If it is called without arguments, it will print the contents of *note
sys.path: 3b7. on the standard output, followed by the value of *note
USER_BASE: 1366. and whether the directory exists, then the same thing
for *note USER_SITE: 1edd, and finally the value of *note
ENABLE_USER_SITE: 473f.

 -- Option: --user-base

     Print the path to the user base directory.

 -- Option: --user-site

     Print the path to the user site-packages directory.

If both options are given, user base and user site will be printed
(always in this order), separated by *note os.pathsep: 1eec.

If any option is given, the script will exit with one of these values:
‘0’ if the user site-packages directory is enabled, ‘1’ if it was
disabled by the user, ‘2’ if it is disabled for security reasons or by
an administrator, and a value greater than 2 if there is an error.

See also
........

   * PEP 370(1) – Per user site-packages directory

   * *note The initialization of the sys.path module search path: 1dfe.
     – The initialization of *note sys.path: 3b7.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0370/


File: python.info,  Node: Custom Python Interpreters,  Next: Importing Modules,  Prev: Python Runtime Services,  Up: The Python Standard Library

5.30 Custom Python Interpreters
===============================

The modules described in this chapter allow writing interfaces similar
to Python’s interactive interpreter.  If you want a Python interpreter
that supports some special feature in addition to the Python language,
you should look at the *note code: 1a. module.  (The *note codeop: 1c.
module is lower-level, used to support compiling a possibly incomplete
chunk of Python code.)

The full list of modules described in this chapter is:

* Menu:

* code — Interpreter base classes::
* codeop — Compile Python code::


File: python.info,  Node: code — Interpreter base classes,  Next: codeop — Compile Python code,  Up: Custom Python Interpreters

5.30.1 ‘code’ — Interpreter base classes
----------------------------------------

'Source code:' Lib/code.py(1)

__________________________________________________________________

The ‘code’ module provides facilities to implement read-eval-print loops
in Python.  Two classes and convenience functions are included which can
be used to build applications which provide an interactive interpreter
prompt.

 -- Class: code.InteractiveInterpreter (locals=None)

     This class deals with parsing and interpreter state (the user’s
     namespace); it does not deal with input buffering or prompting or
     input file naming (the filename is always passed in explicitly).
     The optional 'locals' argument specifies a mapping to use as the
     namespace in which code will be executed; it defaults to a newly
     created dictionary with key ‘'__name__'’ set to ‘'__console__'’ and
     key ‘'__doc__'’ set to ‘None’.

     Note that functions and classes objects created under an
     ‘InteractiveInterpreter’ instance will belong to the namespace
     specified by 'locals'.  They are only pickleable if 'locals' is the
     namespace of an existing module.

 -- Class: code.InteractiveConsole (locals=None, filename='<console>',
          local_exit=False)

     Closely emulate the behavior of the interactive Python interpreter.
     This class builds on *note InteractiveInterpreter: 16e1. and adds
     prompting using the familiar ‘sys.ps1’ and ‘sys.ps2’, and input
     buffering.  If 'local_exit' is true, ‘exit()’ and ‘quit()’ in the
     console will not raise *note SystemExit: d69, but instead return to
     the calling code.

     Changed in version 3.13: Added 'local_exit' parameter.

 -- Function: code.interact (banner=None, readfunc=None, local=None,
          exitmsg=None, local_exit=False)

     Convenience function to run a read-eval-print loop.  This creates a
     new instance of *note InteractiveConsole: 2552. and sets 'readfunc'
     to be used as the *note InteractiveConsole.raw_input(): 474d.
     method, if provided.  If 'local' is provided, it is passed to the
     ‘InteractiveConsole’ constructor for use as the default namespace
     for the interpreter loop.  If 'local_exit' is provided, it is
     passed to the ‘InteractiveConsole’ constructor.  The *note
     interact(): 474e. method of the instance is then run with 'banner'
     and 'exitmsg' passed as the banner and exit message to use, if
     provided.  The console object is discarded after use.

     Changed in version 3.6: Added 'exitmsg' parameter.

     Changed in version 3.13: Added 'local_exit' parameter.

 -- Function: code.compile_command (source, filename='<input>',
          symbol='single')

     This function is useful for programs that want to emulate Python’s
     interpreter main loop (a.k.a.  the read-eval-print loop).  The
     tricky part is to determine when the user has entered an incomplete
     command that can be completed by entering more text (as opposed to
     a complete command or a syntax error).  This function 'almost'
     always makes the same decision as the real interpreter main loop.

     'source' is the source string; 'filename' is the optional filename
     from which source was read, defaulting to ‘'<input>'’; and 'symbol'
     is the optional grammar start symbol, which should be ‘'single'’
     (the default), ‘'eval'’ or ‘'exec'’.

     Returns a code object (the same as ‘compile(source, filename,
     symbol)’) if the command is complete and valid; ‘None’ if the
     command is incomplete; raises *note SyntaxError: 18d. if the
     command is complete and contains a syntax error, or raises *note
     OverflowError: 888. or *note ValueError: 202. if the command
     contains an invalid literal.

* Menu:

* Interactive Interpreter Objects::
* Interactive Console Objects::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/code.py


File: python.info,  Node: Interactive Interpreter Objects,  Next: Interactive Console Objects,  Up: code — Interpreter base classes

5.30.1.1 Interactive Interpreter Objects
........................................

 -- Method: InteractiveInterpreter.runsource (source,
          filename='<input>', symbol='single')

     Compile and run some source in the interpreter.  Arguments are the
     same as for *note compile_command(): 474f.; the default for
     'filename' is ‘'<input>'’, and for 'symbol' is ‘'single'’.  One of
     several things can happen:

        * The input is incorrect; *note compile_command(): 474f. raised
          an exception (*note SyntaxError: 18d. or *note OverflowError:
          888.).  A syntax traceback will be printed by calling the
          *note showsyntaxerror(): 4753. method.  ‘runsource()’ returns
          ‘False’.

        * The input is incomplete, and more input is required; *note
          compile_command(): 474f. returned ‘None’.  ‘runsource()’
          returns ‘True’.

        * The input is complete; *note compile_command(): 474f. returned
          a code object.  The code is executed by calling the *note
          runcode(): 4754. (which also handles run-time exceptions,
          except for *note SystemExit: d69.).  ‘runsource()’ returns
          ‘False’.

     The return value can be used to decide whether to use ‘sys.ps1’ or
     ‘sys.ps2’ to prompt the next line.

 -- Method: InteractiveInterpreter.runcode (code)

     Execute a code object.  When an exception occurs, *note
     showtraceback(): dfe. is called to display a traceback.  All
     exceptions are caught except *note SystemExit: d69, which is
     allowed to propagate.

     A note about *note KeyboardInterrupt: 9dc.: this exception may
     occur elsewhere in this code, and may not always be caught.  The
     caller should be prepared to deal with it.

 -- Method: InteractiveInterpreter.showsyntaxerror (filename=None)

     Display the syntax error that just occurred.  This does not display
     a stack trace because there isn’t one for syntax errors.  If
     'filename' is given, it is stuffed into the exception instead of
     the default filename provided by Python’s parser, because it always
     uses ‘'<string>'’ when reading from a string.  The output is
     written by the *note write(): 4755. method.

 -- Method: InteractiveInterpreter.showtraceback ()

     Display the exception that just occurred.  We remove the first
     stack item because it is within the interpreter object
     implementation.  The output is written by the *note write(): 4755.
     method.

     Changed in version 3.5: The full chained traceback is displayed
     instead of just the primary traceback.

 -- Method: InteractiveInterpreter.write (data)

     Write a string to the standard error stream (‘sys.stderr’).
     Derived classes should override this to provide the appropriate
     output handling as needed.


File: python.info,  Node: Interactive Console Objects,  Prev: Interactive Interpreter Objects,  Up: code — Interpreter base classes

5.30.1.2 Interactive Console Objects
....................................

The *note InteractiveConsole: 2552. class is a subclass of *note
InteractiveInterpreter: 16e1, and so offers all the methods of the
interpreter objects as well as the following additions.

 -- Method: InteractiveConsole.interact (banner=None, exitmsg=None)

     Closely emulate the interactive Python console.  The optional
     'banner' argument specify the banner to print before the first
     interaction; by default it prints a banner similar to the one
     printed by the standard Python interpreter, followed by the class
     name of the console object in parentheses (so as not to confuse
     this with the real interpreter – since it’s so close!).

     The optional 'exitmsg' argument specifies an exit message printed
     when exiting.  Pass the empty string to suppress the exit message.
     If 'exitmsg' is not given or ‘None’, a default message is printed.

     Changed in version 3.4: To suppress printing any banner, pass an
     empty string.

     Changed in version 3.6: Print an exit message when exiting.

 -- Method: InteractiveConsole.push (line)

     Push a line of source text to the interpreter.  The line should not
     have a trailing newline; it may have internal newlines.  The line
     is appended to a buffer and the interpreter’s *note runsource():
     4752. method is called with the concatenated contents of the buffer
     as source.  If this indicates that the command was executed or
     invalid, the buffer is reset; otherwise, the command is incomplete,
     and the buffer is left as it was after the line was appended.  The
     return value is ‘True’ if more input is required, ‘False’ if the
     line was dealt with in some way (this is the same as
     ‘runsource()’).

 -- Method: InteractiveConsole.resetbuffer ()

     Remove any unhandled source text from the input buffer.

 -- Method: InteractiveConsole.raw_input (prompt='')

     Write a prompt and read a line.  The returned line does not include
     the trailing newline.  When the user enters the EOF key sequence,
     *note EOFError: 1321. is raised.  The base implementation reads
     from ‘sys.stdin’; a subclass may replace this with a different
     implementation.


File: python.info,  Node: codeop — Compile Python code,  Prev: code — Interpreter base classes,  Up: Custom Python Interpreters

5.30.2 ‘codeop’ — Compile Python code
-------------------------------------

'Source code:' Lib/codeop.py(1)

__________________________________________________________________

The ‘codeop’ module provides utilities upon which the Python
read-eval-print loop can be emulated, as is done in the *note code: 1a.
module.  As a result, you probably don’t want to use the module
directly; if you want to include such a loop in your program you
probably want to use the ‘code’ module instead.

There are two parts to this job:

  1. Being able to tell if a line of input completes a Python statement:
     in short, telling whether to print ‘‘>>>’’ or ‘‘...’’ next.

  2. Remembering which future statements the user has entered, so
     subsequent input can be compiled with these in effect.

The ‘codeop’ module provides a way of doing each of these things, and a
way of doing them both.

To do just the former:

 -- Function: codeop.compile_command (source, filename='<input>',
          symbol='single')

     Tries to compile 'source', which should be a string of Python code
     and return a code object if 'source' is valid Python code.  In that
     case, the filename attribute of the code object will be 'filename',
     which defaults to ‘'<input>'’.  Returns ‘None’ if 'source' is 'not'
     valid Python code, but is a prefix of valid Python code.

     If there is a problem with 'source', an exception will be raised.
     *note SyntaxError: 18d. is raised if there is invalid Python
     syntax, and *note OverflowError: 888. or *note ValueError: 202. if
     there is an invalid literal.

     The 'symbol' argument determines whether 'source' is compiled as a
     statement (‘'single'’, the default), as a sequence of *note
     statement: 2951. (‘'exec'’) or as an *note expression: 2135.
     (‘'eval'’).  Any other value will cause *note ValueError: 202. to
     be raised.

          Note: It is possible (but not likely) that the parser stops
          parsing with a successful outcome before reaching the end of
          the source; in this case, trailing symbols may be ignored
          instead of causing an error.  For example, a backslash
          followed by two newlines may be followed by arbitrary garbage.
          This will be fixed once the API for the parser is better.

 -- Class: codeop.Compile

     Instances of this class have *note __call__(): 55b. methods
     identical in signature to the built-in function *note compile():
     192, but with the difference that if the instance compiles program
     text containing a *note __future__: 0. statement, the instance
     ‘remembers’ and compiles all subsequent program texts with the
     statement in force.

 -- Class: codeop.CommandCompiler

     Instances of this class have *note __call__(): 55b. methods
     identical in signature to *note compile_command(): 18f8.; the
     difference is that if the instance compiles program text containing
     a *note __future__: 0. statement, the instance ‘remembers’ and
     compiles all subsequent program texts with the statement in force.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/codeop.py


File: python.info,  Node: Importing Modules,  Next: Python Language Services,  Prev: Custom Python Interpreters,  Up: The Python Standard Library

5.31 Importing Modules
======================

The modules described in this chapter provide new ways to import other
Python modules and hooks for customizing the import process.

The full list of modules described in this chapter is:

* Menu:

* zipimport — Import modules from Zip archives::
* pkgutil — Package extension utility::
* modulefinder — Find modules used by a script::
* runpy — Locating and executing Python modules::
* importlib — The implementation of import::
* importlib.resources – Package resource reading, opening and access: importlib resources – Package resource reading opening and access.
* importlib.resources.abc – Abstract base classes for resources: importlib resources abc – Abstract base classes for resources.
* importlib.metadata – Accessing package metadata: importlib metadata – Accessing package metadata.
* The initialization of the sys.path module search path: The initialization of the sys path module search path.


File: python.info,  Node: zipimport — Import modules from Zip archives,  Next: pkgutil — Package extension utility,  Up: Importing Modules

5.31.1 ‘zipimport’ — Import modules from Zip archives
-----------------------------------------------------

'Source code:' Lib/zipimport.py(1)

__________________________________________________________________

This module adds the ability to import Python modules (‘*.py’, ‘*.pyc’)
and packages from ZIP-format archives.  It is usually not needed to use
the ‘zipimport’ module explicitly; it is automatically used by the
built-in *note import: 5e5. mechanism for *note sys.path: 3b7. items
that are paths to ZIP archives.

Typically, *note sys.path: 3b7. is a list of directory names as strings.
This module also allows an item of ‘sys.path’ to be a string naming a
ZIP file archive.  The ZIP archive can contain a subdirectory structure
to support package imports, and a path within the archive can be
specified to only import from a subdirectory.  For example, the path
‘example.zip/lib/’ would only import from the ‘lib/’ subdirectory within
the archive.

Any files may be present in the ZIP archive, but importers are only
invoked for ‘.py’ and ‘.pyc’ files.  ZIP import of dynamic modules
(‘.pyd’, ‘.so’) is disallowed.  Note that if an archive only contains
‘.py’ files, Python will not attempt to modify the archive by adding the
corresponding ‘.pyc’ file, meaning that if a ZIP archive doesn’t contain
‘.pyc’ files, importing may be rather slow.

Changed in version 3.13: ZIP64 is supported

Changed in version 3.8: Previously, ZIP archives with an archive comment
were not supported.

See also
........

PKZIP Application Note(2)

     Documentation on the ZIP file format by Phil Katz, the creator of
     the format and algorithms used.

PEP 273(3) - Import Modules from Zip Archives

     Written by James C. Ahlstrom, who also provided an implementation.
     Python 2.3 follows the specification in PEP 273(4), but uses an
     implementation written by Just van Rossum that uses the import
     hooks described in PEP 302(5).

*note importlib: 77. - The implementation of the import machinery

     Package providing the relevant protocols for all importers to
     implement.

This module defines an exception:

 -- Exception: zipimport.ZipImportError

     Exception raised by zipimporter objects.  It’s a subclass of *note
     ImportError: 41c, so it can be caught as ‘ImportError’, too.

* Menu:

* zipimporter Objects::
* Examples: Examples<33>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/zipimport.py

   (2) https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT

   (3) https://peps.python.org/pep-0273/

   (4) https://peps.python.org/pep-0273/

   (5) https://peps.python.org/pep-0302/


File: python.info,  Node: zipimporter Objects,  Next: Examples<33>,  Up: zipimport — Import modules from Zip archives

5.31.1.1 zipimporter Objects
............................

*note zipimporter: 4768. is the class for importing ZIP files.

 -- Class: zipimport.zipimporter (archivepath)

     Create a new zipimporter instance.  'archivepath' must be a path to
     a ZIP file, or to a specific path within a ZIP file.  For example,
     an 'archivepath' of ‘foo/bar.zip/lib’ will look for modules in the
     ‘lib’ directory inside the ZIP file ‘foo/bar.zip’ (provided that it
     exists).

     *note ZipImportError: 4765. is raised if 'archivepath' doesn’t
     point to a valid ZIP archive.

     Changed in version 3.12: Methods ‘find_loader()’ and
     ‘find_module()’, deprecated in 3.10 are now removed.  Use *note
     find_spec(): 864. instead.

      -- Method: create_module (spec)

          Implementation of *note importlib.abc.Loader.create_module():
          cd4. that returns *note None: 678. to explicitly request the
          default semantics.

          Added in version 3.10.

      -- Method: exec_module (module)

          Implementation of *note importlib.abc.Loader.exec_module():
          871.

          Added in version 3.10.

      -- Method: find_spec (fullname, target=None)

          An implementation of *note
          importlib.abc.PathEntryFinder.find_spec(): 873.

          Added in version 3.10.

      -- Method: get_code (fullname)

          Return the code object for the specified module.  Raise *note
          ZipImportError: 4765. if the module couldn’t be imported.

      -- Method: get_data (pathname)

          Return the data associated with 'pathname'.  Raise *note
          OSError: 41a. if the file wasn’t found.

          Changed in version 3.3: *note IOError: 1090. used to be
          raised, it is now an alias of *note OSError: 41a.

      -- Method: get_filename (fullname)

          Return the value ‘__file__’ would be set to if the specified
          module was imported.  Raise *note ZipImportError: 4765. if the
          module couldn’t be imported.

          Added in version 3.1.

      -- Method: get_source (fullname)

          Return the source code for the specified module.  Raise *note
          ZipImportError: 4765. if the module couldn’t be found, return
          *note None: 678. if the archive does contain the module, but
          has no source for it.

      -- Method: is_package (fullname)

          Return ‘True’ if the module specified by 'fullname' is a
          package.  Raise *note ZipImportError: 4765. if the module
          couldn’t be found.

      -- Method: load_module (fullname)

          Load the module specified by 'fullname'.  'fullname' must be
          the fully qualified (dotted) module name.  Returns the
          imported module on success, raises *note ZipImportError: 4765.
          on failure.

          Deprecated since version 3.10: Use *note exec_module(): 312.
          instead.

      -- Method: invalidate_caches ()

          Clear out the internal cache of information about files found
          within the ZIP archive.

          Added in version 3.10.

      -- Attribute: archive

          The file name of the importer’s associated ZIP file, without a
          possible subpath.

      -- Attribute: prefix

          The subpath within the ZIP file where modules are searched.
          This is the empty string for zipimporter objects which point
          to the root of the ZIP file.

     The *note archive: 476e. and *note prefix: 476f. attributes, when
     combined with a slash, equal the original 'archivepath' argument
     given to the ‘zipimporter’ constructor.


File: python.info,  Node: Examples<33>,  Prev: zipimporter Objects,  Up: zipimport — Import modules from Zip archives

5.31.1.2 Examples
.................

Here is an example that imports a module from a ZIP archive - note that
the ‘zipimport’ module is not explicitly used.

     $ unzip -l example_archive.zip
     Archive:  example_archive.zip
       Length     Date   Time    Name
      --------    ----   ----    ----
          8467  01-01-00 12:30   example.py
      --------                   -------
          8467                   1 file

     >>> import sys
     >>> # Add the archive to the front of the module search path
     >>> sys.path.insert(0, 'example_archive.zip')
     >>> import example
     >>> example.__file__
     'example_archive.zip/example.py'


File: python.info,  Node: pkgutil — Package extension utility,  Next: modulefinder — Find modules used by a script,  Prev: zipimport — Import modules from Zip archives,  Up: Importing Modules

5.31.2 ‘pkgutil’ — Package extension utility
--------------------------------------------

'Source code:' Lib/pkgutil.py(1)

__________________________________________________________________

This module provides utilities for the import system, in particular
package support.

 -- Class: pkgutil.ModuleInfo (module_finder, name, ispkg)

     A namedtuple that holds a brief summary of a module’s info.

     Added in version 3.6.

 -- Function: pkgutil.extend_path (path, name)

     Extend the search path for the modules which comprise a package.
     Intended use is to place the following code in a package’s
     ‘__init__.py’:

          from pkgutil import extend_path
          __path__ = extend_path(__path__, __name__)

     For each directory on *note sys.path: 3b7. that has a subdirectory
     that matches the package name, add the subdirectory to the
     package’s *note __path__: 1e0c.  This is useful if one wants to
     distribute different parts of a single logical package as multiple
     directories.

     It also looks for ‘*.pkg’ files beginning where ‘*’ matches the
     'name' argument.  This feature is similar to ‘*.pth’ files (see the
     *note site: c7. module for more information), except that it
     doesn’t special-case lines starting with ‘import’.  A ‘*.pkg’ file
     is trusted at face value: apart from skipping blank lines and
     ignoring comments, all entries found in a ‘*.pkg’ file are added to
     the path, regardless of whether they exist on the filesystem (this
     is a feature).

     If the input path is not a list (as is the case for frozen
     packages) it is returned unchanged.  The input path is not
     modified; an extended copy is returned.  Items are only appended to
     the copy at the end.

     It is assumed that *note sys.path: 3b7. is a sequence.  Items of
     ‘sys.path’ that are not strings referring to existing directories
     are ignored.  Unicode items on ‘sys.path’ that cause errors when
     used as filenames may cause this function to raise an exception (in
     line with *note os.path.isdir(): a1d. behavior).

 -- Function: pkgutil.find_loader (fullname)

     Retrieve a module *note loader: 17c1. for the given 'fullname'.

     This is a backwards compatibility wrapper around *note
     importlib.util.find_spec(): 2cd. that converts most failures to
     *note ImportError: 41c. and only returns the loader rather than the
     full *note importlib.machinery.ModuleSpec: 200d.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(2) import emulation.

     Changed in version 3.4: Updated to be based on PEP 451(3)

     Deprecated since version 3.12, will be removed in version 3.14: Use
     *note importlib.util.find_spec(): 2cd. instead.

 -- Function: pkgutil.get_importer (path_item)

     Retrieve a *note finder: 20cd. for the given 'path_item'.

     The returned finder is cached in *note sys.path_importer_cache:
     5e7. if it was newly created by a path hook.

     The cache (or part of it) can be cleared manually if a rescan of
     *note sys.path_hooks: 105f. is necessary.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(4) import emulation.

 -- Function: pkgutil.get_loader (module_or_name)

     Get a *note loader: 17c1. object for 'module_or_name'.

     If the module or package is accessible via the normal import
     mechanism, a wrapper around the relevant part of that machinery is
     returned.  Returns ‘None’ if the module cannot be found or
     imported.  If the named module is not already imported, its
     containing package (if any) is imported, in order to establish the
     package ‘__path__’.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(5) import emulation.

     Changed in version 3.4: Updated to be based on PEP 451(6)

     Deprecated since version 3.12, will be removed in version 3.14: Use
     *note importlib.util.find_spec(): 2cd. instead.

 -- Function: pkgutil.iter_importers (fullname='')

     Yield *note finder: 20cd. objects for the given module name.

     If 'fullname' contains a ‘'.'’, the finders will be for the package
     containing 'fullname', otherwise they will be all registered top
     level finders (i.e.  those on both *note sys.meta_path: d53. and
     *note sys.path_hooks: 105f.).

     If the named module is in a package, that package is imported as a
     side effect of invoking this function.

     If no module name is specified, all top level finders are produced.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(7) import emulation.

 -- Function: pkgutil.iter_modules (path=None, prefix='')

     Yields *note ModuleInfo: d75. for all submodules on 'path', or, if
     'path' is ‘None’, all top-level modules on *note sys.path: 3b7.

     'path' should be either ‘None’ or a list of paths to look for
     modules in.

     'prefix' is a string to output on the front of every module name on
     output.

          Note: Only works for a *note finder: 20cd. which defines an
          ‘iter_modules()’ method.  This interface is non-standard, so
          the module also provides implementations for *note
          importlib.machinery.FileFinder: 10b0. and *note
          zipimport.zipimporter: 4768.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(8) import emulation.

 -- Function: pkgutil.walk_packages (path=None, prefix='', onerror=None)

     Yields *note ModuleInfo: d75. for all modules recursively on
     'path', or, if 'path' is ‘None’, all accessible modules.

     'path' should be either ‘None’ or a list of paths to look for
     modules in.

     'prefix' is a string to output on the front of every module name on
     output.

     Note that this function must import all 'packages' ('not' all
     modules!)  on the given 'path', in order to access the ‘__path__’
     attribute to find submodules.

     'onerror' is a function which gets called with one argument (the
     name of the package which was being imported) if any exception
     occurs while trying to import a package.  If no 'onerror' function
     is supplied, *note ImportError: 41c.s are caught and ignored, while
     all other exceptions are propagated, terminating the search.

     Examples:

          # list all modules python can access
          walk_packages()

          # list all submodules of ctypes
          walk_packages(ctypes.__path__, ctypes.__name__ + '.')

          Note: Only works for a *note finder: 20cd. which defines an
          ‘iter_modules()’ method.  This interface is non-standard, so
          the module also provides implementations for *note
          importlib.machinery.FileFinder: 10b0. and *note
          zipimport.zipimporter: 4768.

     Changed in version 3.3: Updated to be based directly on *note
     importlib: 77. rather than relying on the package internal PEP
     302(9) import emulation.

 -- Function: pkgutil.get_data (package, resource)

     Get a resource from a package.

     This is a wrapper for the *note loader: 17c1. *note get_data: 4777.
     API. The 'package' argument should be the name of a package, in
     standard module format (‘foo.bar’).  The 'resource' argument should
     be in the form of a relative filename, using ‘/’ as the path
     separator.

     The function returns a binary string that is the contents of the
     specified resource.

     This function uses the *note loader: 17c1. method *note get_data():
     4778. to support modules installed in the filesystem, but also in
     zip files, databases, or elsewhere.

     For packages located in the filesystem, which have already been
     imported, this is the rough equivalent of:

          d = os.path.dirname(sys.modules[package].__file__)
          data = open(os.path.join(d, resource), 'rb').read()

     Like the *note open(): 51f. function, ‘get_data()’ can follow
     parent directories (‘../’) and absolute paths (starting with ‘/’ or
     ‘C:/’, for example).  It can open compilation/installation
     artifacts like ‘.py’ and ‘.pyc’ files or files with *note reserved
     filenames: 223.  To be compatible with non-filesystem loaders,
     avoid using these features.

          Warning: This function is intended for trusted input.  It does
          not verify that 'resource' “belongs” to 'package'.

     If you use a user-provided 'resource' path, consider verifying it.
     For example, require an alphanumeric filename with a known
     extension, or install and check a list of known resources.

     If the package cannot be located or loaded, or it uses a *note
     loader: 17c1. which does not support *note get_data: 4777, then
     ‘None’ is returned.  In particular, the loader for *note namespace
     packages: 1e06. does not support ‘get_data’.

     See also
     ........

     The *note importlib.resources: 7b. module provides structured
     access to module resources.

 -- Function: pkgutil.resolve_name (name)

     Resolve a name to an object.

     This functionality is used in numerous places in the standard
     library (see bpo-12915(10)) - and equivalent functionality is also
     in widely used third-party packages such as setuptools, Django and
     Pyramid.

     It is expected that 'name' will be a string in one of the following
     formats, where W is shorthand for a valid Python identifier and dot
     stands for a literal period in these pseudo-regexes:

        * ‘W(.W)*’

        * ‘W(.W)*:(W(.W)*)?’

     The first form is intended for backward compatibility only.  It
     assumes that some part of the dotted name is a package, and the
     rest is an object somewhere within that package, possibly nested
     inside other objects.  Because the place where the package stops
     and the object hierarchy starts can’t be inferred by inspection,
     repeated attempts to import must be done with this form.

     In the second form, the caller makes the division point clear
     through the provision of a single colon: the dotted name to the
     left of the colon is a package to be imported, and the dotted name
     to the right is the object hierarchy within that package.  Only one
     import is needed in this form.  If it ends with the colon, then a
     module object is returned.

     The function will return an object (which might be a module), or
     raise one of the following exceptions:

     *note ValueError: 202. – if 'name' isn’t in a recognised format.

     *note ImportError: 41c. – if an import failed when it shouldn’t
     have.

     *note AttributeError: 34e. – If a failure occurred when traversing
     the object hierarchy within the imported package to get to the
     desired object.

     Added in version 3.9.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pkgutil.py

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-0451/

   (4) https://peps.python.org/pep-0302/

   (5) https://peps.python.org/pep-0302/

   (6) https://peps.python.org/pep-0451/

   (7) https://peps.python.org/pep-0302/

   (8) https://peps.python.org/pep-0302/

   (9) https://peps.python.org/pep-0302/

   (10) https://bugs.python.org/issue?@action=redirect&bpo=12915


File: python.info,  Node: modulefinder — Find modules used by a script,  Next: runpy — Locating and executing Python modules,  Prev: pkgutil — Package extension utility,  Up: Importing Modules

5.31.3 ‘modulefinder’ — Find modules used by a script
-----------------------------------------------------

'Source code:' Lib/modulefinder.py(1)

__________________________________________________________________

This module provides a *note ModuleFinder: 1b93. class that can be used
to determine the set of modules imported by a script.  ‘modulefinder.py’
can also be run as a script, giving the filename of a Python script as
its argument, after which a report of the imported modules will be
printed.

 -- Function: modulefinder.AddPackagePath (pkg_name, path)

     Record that the package named 'pkg_name' can be found in the
     specified 'path'.

 -- Function: modulefinder.ReplacePackage (oldname, newname)

     Allows specifying that the module named 'oldname' is in fact the
     package named 'newname'.

 -- Class: modulefinder.ModuleFinder (path=None, debug=0, excludes=[],
          replace_paths=[])

     This class provides *note run_script(): 477f. and *note report():
     4780. methods to determine the set of modules imported by a script.
     'path' can be a list of directories to search for modules; if not
     specified, ‘sys.path’ is used.  'debug' sets the debugging level;
     higher values make the class print debugging messages about what
     it’s doing.  'excludes' is a list of module names to exclude from
     the analysis.  'replace_paths' is a list of ‘(oldpath, newpath)’
     tuples that will be replaced in module paths.

      -- Method: report ()

          Print a report to standard output that lists the modules
          imported by the script and their paths, as well as modules
          that are missing or seem to be missing.

      -- Method: run_script (pathname)

          Analyze the contents of the 'pathname' file, which must
          contain Python code.

      -- Attribute: modules

          A dictionary mapping module names to modules.  See *note
          Example usage of ModuleFinder: 4782.

* Menu:

* Example usage of ModuleFinder::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/modulefinder.py


File: python.info,  Node: Example usage of ModuleFinder,  Up: modulefinder — Find modules used by a script

5.31.3.1 Example usage of ‘ModuleFinder’
........................................

The script that is going to get analyzed later on (bacon.py):

     import re, itertools

     try:
         import baconhameggs
     except ImportError:
         pass

     try:
         import guido.python.ham
     except ImportError:
         pass

The script that will output the report of bacon.py:

     from modulefinder import ModuleFinder

     finder = ModuleFinder()
     finder.run_script('bacon.py')

     print('Loaded modules:')
     for name, mod in finder.modules.items():
         print('%s: ' % name, end='')
         print(','.join(list(mod.globalnames.keys())[:3]))

     print('-'*50)
     print('Modules not imported:')
     print('\n'.join(finder.badmodules.keys()))

Sample output (may vary depending on the architecture):

     Loaded modules:
     _types:
     copyreg:  _inverted_registry,_slotnames,__all__
     re._compiler:  isstring,_sre,_optimize_unicode
     _sre:
     re._constants:  REPEAT_ONE,makedict,AT_END_LINE
     sys:
     re:  __module__,finditer,_expand
     itertools:
     __main__:  re,itertools,baconhameggs
     re._parser:  _PATTERNENDERS,SRE_FLAG_UNICODE
     array:
     types:  __module__,IntType,TypeType
     ---------------------------------------------------
     Modules not imported:
     guido.python.ham
     baconhameggs


File: python.info,  Node: runpy — Locating and executing Python modules,  Next: importlib — The implementation of import,  Prev: modulefinder — Find modules used by a script,  Up: Importing Modules

5.31.4 ‘runpy’ — Locating and executing Python modules
------------------------------------------------------

'Source code:' Lib/runpy.py(1)

__________________________________________________________________

The ‘runpy’ module is used to locate and run Python modules without
importing them first.  Its main use is to implement the *note -m: 5e4.
command line switch that allows scripts to be located using the Python
module namespace rather than the filesystem.

Note that this is 'not' a sandbox module - all code is executed in the
current process, and any side effects (such as cached imports of other
modules) will remain in place after the functions have returned.

Furthermore, any functions and classes defined by the executed code are
not guaranteed to work correctly after a ‘runpy’ function has returned.
If that limitation is not acceptable for a given use case, *note
importlib: 77. is likely to be a more suitable choice than this module.

The ‘runpy’ module provides two functions:

 -- Function: runpy.run_module (mod_name, init_globals=None,
          run_name=None, alter_sys=False)

     Execute the code of the specified module and return the resulting
     module’s globals dictionary.  The module’s code is first located
     using the standard import mechanism (refer to PEP 302(2) for
     details) and then executed in a fresh module namespace.

     The 'mod_name' argument should be an absolute module name.  If the
     module name refers to a package rather than a normal module, then
     that package is imported and the *note __main__: 1. submodule
     within that package is then executed and the resulting module
     globals dictionary returned.

     The optional dictionary argument 'init_globals' may be used to
     pre-populate the module’s globals dictionary before the code is
     executed.  'init_globals' will not be modified.  If any of the
     special global variables below are defined in 'init_globals', those
     definitions are overridden by ‘run_module()’.

     The special global variables ‘__name__’, ‘__spec__’, ‘__file__’,
     ‘__cached__’, ‘__loader__’ and ‘__package__’ are set in the globals
     dictionary before the module code is executed.  (Note that this is
     a minimal set of variables - other variables may be set implicitly
     as an interpreter implementation detail.)

     ‘__name__’ is set to 'run_name' if this optional argument is not
     *note None: 678, to ‘mod_name + '.__main__'’ if the named module is
     a package and to the 'mod_name' argument otherwise.

     ‘__spec__’ will be set appropriately for the 'actually' imported
     module (that is, ‘__spec__.name’ will always be 'mod_name' or
     ‘mod_name + '.__main__'’, never 'run_name').

     ‘__file__’, ‘__cached__’, ‘__loader__’ and ‘__package__’ are *note
     set as normal: 20c3. based on the module spec.

     If the argument 'alter_sys' is supplied and evaluates to *note
     True: c2d, then ‘sys.argv[0]’ is updated with the value of
     ‘__file__’ and ‘sys.modules[__name__]’ is updated with a temporary
     module object for the module being executed.  Both ‘sys.argv[0]’
     and ‘sys.modules[__name__]’ are restored to their original values
     before the function returns.

     Note that this manipulation of *note sys: d9. is not thread-safe.
     Other threads may see the partially initialised module, as well as
     the altered list of arguments.  It is recommended that the ‘sys’
     module be left alone when invoking this function from threaded
     code.

     See also
     ........

     The *note -m: 5e4. option offering equivalent functionality from
     the command line.

     Changed in version 3.1: Added ability to execute packages by
     looking for a *note __main__: 1. submodule.

     Changed in version 3.2: Added ‘__cached__’ global variable (see PEP
     3147(3)).

     Changed in version 3.4: Updated to take advantage of the module
     spec feature added by PEP 451(4).  This allows ‘__cached__’ to be
     set correctly for modules run this way, as well as ensuring the
     real module name is always accessible as ‘__spec__.name’.

     Changed in version 3.12: The setting of ‘__cached__’, ‘__loader__’,
     and ‘__package__’ are deprecated.  See *note ModuleSpec: 200d. for
     alternatives.

 -- Function: runpy.run_path (path_name, init_globals=None,
          run_name=None)

     Execute the code at the named filesystem location and return the
     resulting module’s globals dictionary.  As with a script name
     supplied to the CPython command line, 'file_path' may refer to a
     Python source file, a compiled bytecode file or a valid *note
     sys.path: 3b7. entry containing a *note __main__: 1. module (e.g.
     a zipfile containing a top-level ‘__main__.py’ file).

     For a simple script, the specified code is simply executed in a
     fresh module namespace.  For a valid *note sys.path: 3b7. entry
     (typically a zipfile or directory), the entry is first added to the
     beginning of ‘sys.path’.  The function then looks for and executes
     a *note __main__: 1. module using the updated path.  Note that
     there is no special protection against invoking an existing
     ‘__main__’ entry located elsewhere on ‘sys.path’ if there is no
     such module at the specified location.

     The optional dictionary argument 'init_globals' may be used to
     pre-populate the module’s globals dictionary before the code is
     executed.  'init_globals' will not be modified.  If any of the
     special global variables below are defined in 'init_globals', those
     definitions are overridden by ‘run_path()’.

     The special global variables ‘__name__’, ‘__spec__’, ‘__file__’,
     ‘__cached__’, ‘__loader__’ and ‘__package__’ are set in the globals
     dictionary before the module code is executed.  (Note that this is
     a minimal set of variables - other variables may be set implicitly
     as an interpreter implementation detail.)

     ‘__name__’ is set to 'run_name' if this optional argument is not
     *note None: 678. and to ‘'<run_path>'’ otherwise.

     If 'file_path' directly references a script file (whether as source
     or as precompiled byte code), then ‘__file__’ will be set to
     'file_path', and ‘__spec__’, ‘__cached__’, ‘__loader__’ and
     ‘__package__’ will all be set to *note None: 678.

     If 'file_path' is a reference to a valid *note sys.path: 3b7.
     entry, then ‘__spec__’ will be set appropriately for the imported
     *note __main__: 1. module (that is, ‘__spec__.name’ will always be
     ‘__main__’).  ‘__file__’, ‘__cached__’, ‘__loader__’ and
     ‘__package__’ will be *note set as normal: 20c3. based on the
     module spec.

     A number of alterations are also made to the *note sys: d9. module.
     Firstly, *note sys.path: 3b7. may be altered as described above.
     ‘sys.argv[0]’ is updated with the value of 'file_path' and
     ‘sys.modules[__name__]’ is updated with a temporary module object
     for the module being executed.  All modifications to items in ‘sys’
     are reverted before the function returns.

     Note that, unlike *note run_module(): 193d, the alterations made to
     *note sys: d9. are not optional in this function as these
     adjustments are essential to allowing the execution of *note
     sys.path: 3b7. entries.  As the thread-safety limitations still
     apply, use of this function in threaded code should be either
     serialised with the import lock or delegated to a separate process.

     See also
     ........

     *note Interface options: 1ed2. for equivalent functionality on the
     command line (‘python path/to/script’).

     Added in version 3.2.

     Changed in version 3.4: Updated to take advantage of the module
     spec feature added by PEP 451(5).  This allows ‘__cached__’ to be
     set correctly in the case where ‘__main__’ is imported from a valid
     *note sys.path: 3b7. entry rather than being executed directly.

     Changed in version 3.12: The setting of ‘__cached__’, ‘__loader__’,
     and ‘__package__’ are deprecated.

See also
........

PEP 338(6) – Executing modules as scripts

     PEP written and implemented by Nick Coghlan.

PEP 366(7) – Main module explicit relative imports

     PEP written and implemented by Nick Coghlan.

PEP 451(8) – A ModuleSpec Type for the Import System

     PEP written and implemented by Eric Snow

*note Command line and environment: 1b4f. - CPython command line details

The *note importlib.import_module(): 51b. function

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/runpy.py

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-3147/

   (4) https://peps.python.org/pep-0451/

   (5) https://peps.python.org/pep-0451/

   (6) https://peps.python.org/pep-0338/

   (7) https://peps.python.org/pep-0366/

   (8) https://peps.python.org/pep-0451/


File: python.info,  Node: importlib — The implementation of import,  Next: importlib resources – Package resource reading opening and access,  Prev: runpy — Locating and executing Python modules,  Up: Importing Modules

5.31.5 ‘importlib’ — The implementation of ‘import’
---------------------------------------------------

Added in version 3.1.

'Source code:' Lib/importlib/__init__.py(1)

__________________________________________________________________

* Menu:

* Introduction: Introduction<12>.
* Functions: Functions<12>.
* importlib.abc – Abstract base classes related to import: importlib abc – Abstract base classes related to import.
* importlib.machinery – Importers and path hooks: importlib machinery – Importers and path hooks.
* importlib.util – Utility code for importers: importlib util – Utility code for importers.
* Examples: Examples<34>.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/importlib/__init__.py


File: python.info,  Node: Introduction<12>,  Next: Functions<12>,  Up: importlib — The implementation of import

5.31.5.1 Introduction
.....................

The purpose of the ‘importlib’ package is three-fold.

One is to provide the implementation of the *note import: 5e5. statement
(and thus, by extension, the *note __import__(): 8dd. function) in
Python source code.  This provides an implementation of ‘import’ which
is portable to any Python interpreter.  This also provides an
implementation which is easier to comprehend than one implemented in a
programming language other than Python.

Two, the components to implement *note import: 5e5. are exposed in this
package, making it easier for users to create their own custom objects
(known generically as an *note importer: 21a8.) to participate in the
import process.

Three, the package contains modules exposing additional functionality
for managing aspects of Python packages:

   * *note importlib.metadata: 7a. presents access to metadata from
     third-party distributions.

   * *note importlib.resources: 7b. provides routines for accessing
     non-code “resources” from Python packages.

See also
........

*note The import statement: 5e5.

     The language reference for the *note import: 5e5. statement.

Packages specification(1)

     Original specification of packages.  Some semantics have changed
     since the writing of this document (e.g.  redirecting based on
     ‘None’ in *note sys.modules: 1655.).

The *note __import__(): 10ab. function

     The *note import: 5e5. statement is syntactic sugar for this
     function.

*note The initialization of the sys.path module search path: 1dfe.

     The initialization of *note sys.path: 3b7.

PEP 235(2)

     Import on Case-Insensitive Platforms

PEP 263(3)

     Defining Python Source Code Encodings

PEP 302(4)

     New Import Hooks

PEP 328(5)

     Imports: Multi-Line and Absolute/Relative

PEP 366(6)

     Main module explicit relative imports

PEP 420(7)

     Implicit namespace packages

PEP 451(8)

     A ModuleSpec Type for the Import System

PEP 488(9)

     Elimination of PYO files

PEP 489(10)

     Multi-phase extension module initialization

PEP 552(11)

     Deterministic pycs

PEP 3120(12)

     Using UTF-8 as the Default Source Encoding

PEP 3147(13)

     PYC Repository Directories

   ---------- Footnotes ----------

   (1) https://www.python.org/doc/essays/packages/

   (2) https://peps.python.org/pep-0235/

   (3) https://peps.python.org/pep-0263/

   (4) https://peps.python.org/pep-0302/

   (5) https://peps.python.org/pep-0328/

   (6) https://peps.python.org/pep-0366/

   (7) https://peps.python.org/pep-0420/

   (8) https://peps.python.org/pep-0451/

   (9) https://peps.python.org/pep-0488/

   (10) https://peps.python.org/pep-0489/

   (11) https://peps.python.org/pep-0552/

   (12) https://peps.python.org/pep-3120/

   (13) https://peps.python.org/pep-3147/


File: python.info,  Node: Functions<12>,  Next: importlib abc – Abstract base classes related to import,  Prev: Introduction<12>,  Up: importlib — The implementation of import

5.31.5.2 Functions
..................

 -- Function: importlib.__import__ (name, globals=None, locals=None,
          fromlist=(), level=0)

     An implementation of the built-in ‘__import__()’ function.

          Note: Programmatic importing of modules should use *note
          import_module(): 51b. instead of this function.

 -- Function: importlib.import_module (name, package=None)

     Import a module.  The 'name' argument specifies what module to
     import in absolute or relative terms (e.g.  either ‘pkg.mod’ or
     ‘..mod’).  If the name is specified in relative terms, then the
     'package' argument must be set to the name of the package which is
     to act as the anchor for resolving the package name (e.g.
     ‘import_module('..mod', 'pkg.subpkg')’ will import ‘pkg.mod’).

     The ‘import_module()’ function acts as a simplifying wrapper around
     *note importlib.__import__(): 10ab.  This means all semantics of
     the function are derived from ‘importlib.__import__()’.  The most
     important difference between these two functions is that
     ‘import_module()’ returns the specified package or module (e.g.
     ‘pkg.mod’), while *note __import__(): 8dd. returns the top-level
     package or module (e.g.  ‘pkg’).

     If you are dynamically importing a module that was created since
     the interpreter began execution (e.g., created a Python source
     file), you may need to call *note invalidate_caches(): c30. in
     order for the new module to be noticed by the import system.

     Changed in version 3.3: Parent packages are automatically imported.

 -- Function: importlib.invalidate_caches ()

     Invalidate the internal caches of finders stored at *note
     sys.meta_path: d53.  If a finder implements ‘invalidate_caches()’
     then it will be called to perform the invalidation.  This function
     should be called if any modules are created/installed while your
     program is running to guarantee all finders will notice the new
     module’s existence.

     Added in version 3.3.

     Changed in version 3.10: Namespace packages created/installed in a
     different *note sys.path: 3b7. location after the same namespace
     was already imported are noticed.

 -- Function: importlib.reload (module)

     Reload a previously imported 'module'.  The argument must be a
     module object, so it must have been successfully imported before.
     This is useful if you have edited the module source file using an
     external editor and want to try out the new version without leaving
     the Python interpreter.  The return value is the module object
     (which can be different if re-importing causes a different object
     to be placed in *note sys.modules: 1655.).

     When ‘reload()’ is executed:

        * Python module’s code is recompiled and the module-level code
          re-executed, defining a new set of objects which are bound to
          names in the module’s dictionary by reusing the *note loader:
          17c1. which originally loaded the module.  The ‘init’ function
          of extension modules is not called a second time.

        * As with all other objects in Python the old objects are only
          reclaimed after their reference counts drop to zero.

        * The names in the module namespace are updated to point to any
          new or changed objects.

        * Other references to the old objects (such as names external to
          the module) are not rebound to refer to the new objects and
          must be updated in each namespace where they occur if that is
          desired.

     There are a number of other caveats:

     When a module is reloaded, its dictionary (containing the module’s
     global variables) is retained.  Redefinitions of names will
     override the old definitions, so this is generally not a problem.
     If the new version of a module does not define a name that was
     defined by the old version, the old definition remains.  This
     feature can be used to the module’s advantage if it maintains a
     global table or cache of objects — with a *note try: 6ec. statement
     it can test for the table’s presence and skip its initialization if
     desired:

          try:
              cache
          except NameError:
              cache = {}

     It is generally not very useful to reload built-in or dynamically
     loaded modules.  Reloading *note sys: d9, *note __main__: 1, *note
     builtins: 12. and other key modules is not recommended.  In many
     cases extension modules are not designed to be initialized more
     than once, and may fail in arbitrary ways when reloaded.

     If a module imports objects from another module using *note from:
     12f3. … *note import: 5e5. …, calling ‘reload()’ for the other
     module does not redefine the objects imported from it — one way
     around this is to re-execute the ‘from’ statement, another is to
     use ‘import’ and qualified names ('module.name') instead.

     If a module instantiates instances of a class, reloading the module
     that defines the class does not affect the method definitions of
     the instances — they continue to use the old class definition.  The
     same is true for derived classes.

     Added in version 3.4.

     Changed in version 3.7: *note ModuleNotFoundError: b61. is raised
     when the module being reloaded lacks a *note ModuleSpec: 200d.

          Warning: This function is not thread-safe.  Calling it from
          multiple threads can result in unexpected behavior.  It’s
          recommended to use the *note threading.Lock: 178a. or other
          synchronization primitives for thread-safe module reloading.


File: python.info,  Node: importlib abc – Abstract base classes related to import,  Next: importlib machinery – Importers and path hooks,  Prev: Functions<12>,  Up: importlib — The implementation of import

5.31.5.3 ‘importlib.abc’ – Abstract base classes related to import
..................................................................

'Source code:' Lib/importlib/abc.py(1)

__________________________________________________________________

The ‘importlib.abc’ module contains all of the core abstract base
classes used by *note import: 5e5.  Some subclasses of the core abstract
base classes are also provided to help in implementing the core ABCs.

ABC hierarchy:

     object
      +-- MetaPathFinder
      +-- PathEntryFinder
      +-- Loader
           +-- ResourceLoader --------+
           +-- InspectLoader          |
                +-- ExecutionLoader --+
                                      +-- FileLoader
                                      +-- SourceLoader

 -- Class: importlib.abc.MetaPathFinder

     An abstract base class representing a *note meta path finder: 10ae.

     Added in version 3.3.

     Changed in version 3.10: No longer a subclass of ‘Finder’.

      -- Method: find_spec (fullname, path, target=None)

          An abstract method for finding a *note spec: 20c5. for the
          specified module.  If this is a top-level import, 'path' will
          be ‘None’.  Otherwise, this is a search for a subpackage or
          module and 'path' will be the value of *note __path__: 1e0c.
          from the parent package.  If a spec cannot be found, ‘None’ is
          returned.  When passed in, ‘target’ is a module object that
          the finder may use to make a more educated guess about what
          spec to return.  *note importlib.util.spec_from_loader(): 874.
          may be useful for implementing concrete ‘MetaPathFinders’.

          Added in version 3.4.

      -- Method: invalidate_caches ()

          An optional method which, when called, should invalidate any
          internal cache used by the finder.  Used by *note
          importlib.invalidate_caches(): c30. when invalidating the
          caches of all finders on *note sys.meta_path: d53.

          Changed in version 3.4: Returns ‘None’ when called instead of
          *note NotImplemented: 7d6.

 -- Class: importlib.abc.PathEntryFinder

     An abstract base class representing a *note path entry finder:
     10af.  Though it bears some similarities to *note MetaPathFinder:
     875, ‘PathEntryFinder’ is meant for use only within the path-based
     import subsystem provided by *note importlib.machinery.PathFinder:
     105e.

     Added in version 3.3.

     Changed in version 3.10: No longer a subclass of ‘Finder’.

      -- Method: find_spec (fullname, target=None)

          An abstract method for finding a *note spec: 20c5. for the
          specified module.  The finder will search for the module only
          within the *note path entry: 21b7. to which it is assigned.
          If a spec cannot be found, ‘None’ is returned.  When passed
          in, ‘target’ is a module object that the finder may use to
          make a more educated guess about what spec to return.  *note
          importlib.util.spec_from_loader(): 874. may be useful for
          implementing concrete ‘PathEntryFinders’.

          Added in version 3.4.

      -- Method: invalidate_caches ()

          An optional method which, when called, should invalidate any
          internal cache used by the finder.  Used by *note
          importlib.machinery.PathFinder.invalidate_caches(): c2f. when
          invalidating the caches of all cached finders.

 -- Class: importlib.abc.Loader

     An abstract base class for a *note loader: 17c1.  See PEP 302(2)
     for the exact definition for a loader.

     Loaders that wish to support resource reading should implement a
     ‘get_resource_reader()’ method as specified by *note
     importlib.resources.abc.ResourceReader: 478f.

     Changed in version 3.7: Introduced the optional
     ‘get_resource_reader()’ method.

      -- Method: create_module (spec)

          A method that returns the module object to use when importing
          a module.  This method may return ‘None’, indicating that
          default module creation semantics should take place.

          Added in version 3.4.

          Changed in version 3.6: This method is no longer optional when
          *note exec_module(): 871. is defined.

      -- Method: exec_module (module)

          An abstract method that executes the module in its own
          namespace when a module is imported or reloaded.  The module
          should already be initialized when ‘exec_module()’ is called.
          When this method exists, *note create_module(): cd4. must be
          defined.

          Added in version 3.4.

          Changed in version 3.6: *note create_module(): cd4. must also
          be defined.

      -- Method: load_module (fullname)

          A legacy method for loading a module.  If the module cannot be
          loaded, *note ImportError: 41c. is raised, otherwise the
          loaded module is returned.

          If the requested module already exists in *note sys.modules:
          1655, that module should be used and reloaded.  Otherwise the
          loader should create a new module and insert it into
          ‘sys.modules’ before any loading begins, to prevent recursion
          from the import.  If the loader inserted a module and the load
          fails, it must be removed by the loader from ‘sys.modules’;
          modules already in ‘sys.modules’ before the loader began
          execution should be left alone.

          The loader should set several attributes on the module (note
          that some of these attributes can change when a module is
          reloaded):

             - *note module.__name__: 13d8.

             - *note module.__file__: 20cc.

             - *note module.__cached__: 2d5. '(deprecated)'

             - *note module.__path__: 1e0c.

             - *note module.__package__: 2d7. '(deprecated)'

             - *note module.__loader__: 2e2. '(deprecated)'

          When *note exec_module(): 871. is available then
          backwards-compatible functionality is provided.

          Changed in version 3.4: Raise *note ImportError: 41c. when
          called instead of *note NotImplementedError: 228.
          Functionality provided when *note exec_module(): 871. is
          available.

          Deprecated since version 3.4, will be removed in version 3.15:
          The recommended API for loading a module is *note
          exec_module(): 871. (and *note create_module(): cd4.).
          Loaders should implement it instead of ‘load_module()’.  The
          import machinery takes care of all the other responsibilities
          of ‘load_module()’ when ‘exec_module()’ is implemented.

 -- Class: importlib.abc.ResourceLoader

     'Superseded by TraversableResources'

          An abstract base class for a *note loader: 17c1. which
          implements the optional PEP 302(3) protocol for loading
          arbitrary resources from the storage back-end.

          Deprecated since version 3.7: This ABC is deprecated in favour
          of supporting resource loading through *note
          importlib.resources.abc.TraversableResources: 2c5.

           -- Method: abstractmethod get_data (path)

                    An abstract method to return the bytes for the data
                    located at 'path'.  Loaders that have a file-like
                    storage back-end that allows storing arbitrary data
                    can implement this abstract method to give direct
                    access to the data stored.  *note OSError: 41a. is
                    to be raised if the 'path' cannot be found.  The
                    'path' is expected to be constructed using a
                    module’s *note __file__: 20cc. attribute or an item
                    from a package’s *note __path__: 1e0c.

                    Changed in version 3.4: Raises *note OSError: 41a.
                    instead of *note NotImplementedError: 228.

 -- Class: importlib.abc.InspectLoader

     An abstract base class for a *note loader: 17c1. which implements
     the optional PEP 302(4) protocol for loaders that inspect modules.

      -- Method: get_code (fullname)

          Return the code object for a module, or ‘None’ if the module
          does not have a code object (as would be the case, for
          example, for a built-in module).  Raise an *note ImportError:
          41c. if loader cannot find the requested module.

               Note: While the method has a default implementation, it
               is suggested that it be overridden if possible for
               performance.

          Changed in version 3.4: No longer abstract and a concrete
          implementation is provided.

      -- Method: abstractmethod get_source (fullname)

               An abstract method to return the source of a module.  It
               is returned as a text string using *note universal
               newlines: d62, translating all recognized line separators
               into ‘'\n'’ characters.  Returns ‘None’ if no source is
               available (e.g.  a built-in module).  Raises *note
               ImportError: 41c. if the loader cannot find the module
               specified.

               Changed in version 3.4: Raises *note ImportError: 41c.
               instead of *note NotImplementedError: 228.

      -- Method: is_package (fullname)

          An optional method to return a true value if the module is a
          package, a false value otherwise.  *note ImportError: 41c. is
          raised if the *note loader: 17c1. cannot find the module.

          Changed in version 3.4: Raises *note ImportError: 41c. instead
          of *note NotImplementedError: 228.

      -- Method: static source_to_code (data, path='<string>')

          Create a code object from Python source.

          The 'data' argument can be whatever the *note compile(): 192.
          function supports (i.e.  string or bytes).  The 'path'
          argument should be the “path” to where the source code
          originated from, which can be an abstract concept (e.g.
          location in a zip file).

          With the subsequent code object one can execute it in a module
          by running ‘exec(code, module.__dict__)’.

          Added in version 3.4.

          Changed in version 3.5: Made the method static.

      -- Method: exec_module (module)

          Implementation of *note Loader.exec_module(): 871.

          Added in version 3.4.

      -- Method: load_module (fullname)

          Implementation of *note Loader.load_module(): 870.

          Deprecated since version 3.4, will be removed in version 3.15:
          use *note exec_module(): 104d. instead.

 -- Class: importlib.abc.ExecutionLoader

     An abstract base class which inherits from *note InspectLoader:
     f8d. that, when implemented, helps a module to be executed as a
     script.  The ABC represents an optional PEP 302(5) protocol.

      -- Method: abstractmethod get_filename (fullname)

               An abstract method that is to return the value of *note
               __file__: 20cc. for the specified module.  If no path is
               available, *note ImportError: 41c. is raised.

               If source code is available, then the method should
               return the path to the source file, regardless of whether
               a bytecode was used to load the module.

               Changed in version 3.4: Raises *note ImportError: 41c.
               instead of *note NotImplementedError: 228.

 -- Class: importlib.abc.FileLoader (fullname, path)

     An abstract base class which inherits from *note ResourceLoader:
     c08. and *note ExecutionLoader: 4792, providing concrete
     implementations of *note ResourceLoader.get_data(): 4777. and *note
     ExecutionLoader.get_filename(): 4793.

     The 'fullname' argument is a fully resolved name of the module the
     loader is to handle.  The 'path' argument is the path to the file
     for the module.

     Added in version 3.3.

      -- Attribute: name

          The name of the module the loader can handle.

      -- Attribute: path

          Path to the file of the module.

      -- Method: load_module (fullname)

          Calls super’s ‘load_module()’.

          Deprecated since version 3.4, will be removed in version 3.15:
          Use *note Loader.exec_module(): 871. instead.

      -- Method: abstractmethod get_filename (fullname)

          Returns *note path: 4795.

      -- Method: abstractmethod get_data (path)

          Reads 'path' as a binary file and returns the bytes from it.

 -- Class: importlib.abc.SourceLoader

     An abstract base class for implementing source (and optionally
     bytecode) file loading.  The class inherits from both *note
     ResourceLoader: c08. and *note ExecutionLoader: 4792, requiring the
     implementation of:

        * *note ResourceLoader.get_data(): 4777.

        * 
          *note ExecutionLoader.get_filename(): 4793.

               Should only return the path to the source file;
               sourceless loading is not supported.

     The abstract methods defined by this class are to add optional
     bytecode file support.  Not implementing these optional methods (or
     causing them to raise *note NotImplementedError: 228.) causes the
     loader to only work with source code.  Implementing the methods
     allows the loader to work with source 'and' bytecode files; it does
     not allow for 'sourceless' loading where only bytecode is provided.
     Bytecode files are an optimization to speed up loading by removing
     the parsing step of Python’s compiler, and so no bytecode-specific
     API is exposed.

      -- Method: path_stats (path)

          Optional abstract method which returns a *note dict: 256.
          containing metadata about the specified path.  Supported
          dictionary keys are:

             - ‘'mtime'’ (mandatory): an integer or floating-point
               number representing the modification time of the source
               code;

             - ‘'size'’ (optional): the size in bytes of the source
               code.

          Any other keys in the dictionary are ignored, to allow for
          future extensions.  If the path cannot be handled, *note
          OSError: 41a. is raised.

          Added in version 3.3.

          Changed in version 3.4: Raise *note OSError: 41a. instead of
          *note NotImplementedError: 228.

      -- Method: path_mtime (path)

          Optional abstract method which returns the modification time
          for the specified path.

          Deprecated since version 3.3: This method is deprecated in
          favour of *note path_stats(): 11ce.  You don’t have to
          implement it, but it is still available for compatibility
          purposes.  Raise *note OSError: 41a. if the path cannot be
          handled.

          Changed in version 3.4: Raise *note OSError: 41a. instead of
          *note NotImplementedError: 228.

      -- Method: set_data (path, data)

          Optional abstract method which writes the specified bytes to a
          file path.  Any intermediate directories which do not exist
          are to be created automatically.

          When writing to the path fails because the path is read-only
          (*note errno.EACCES: 2466./*note PermissionError: d6b.), do
          not propagate the exception.

          Changed in version 3.4: No longer raises *note
          NotImplementedError: 228. when called.

      -- Method: get_code (fullname)

          Concrete implementation of *note InspectLoader.get_code():
          f8e.

      -- Method: exec_module (module)

          Concrete implementation of *note Loader.exec_module(): 871.

          Added in version 3.4.

      -- Method: load_module (fullname)

          Concrete implementation of *note Loader.load_module(): 870.

          Deprecated since version 3.4, will be removed in version 3.15:
          Use *note exec_module(): 104e. instead.

      -- Method: get_source (fullname)

          Concrete implementation of *note InspectLoader.get_source():
          f91.

      -- Method: is_package (fullname)

          Concrete implementation of *note InspectLoader.is_package():
          4790.  A module is determined to be a package if its file path
          (as provided by *note ExecutionLoader.get_filename(): 4793.)
          is a file named ‘__init__’ when the file extension is removed
          'and' the module name itself does not end in ‘__init__’.

 -- Class: importlib.abc.ResourceReader

     'Superseded by TraversableResources'

     An *note abstract base class: 11fa. to provide the ability to read
     'resources'.

     From the perspective of this ABC, a 'resource' is a binary artifact
     that is shipped within a package.  Typically this is something like
     a data file that lives next to the ‘__init__.py’ file of the
     package.  The purpose of this class is to help abstract out the
     accessing of such data files so that it does not matter if the
     package and its data file(s) are stored e.g.  in a zip file versus
     on the file system.

     For any of methods of this class, a 'resource' argument is expected
     to be a *note path-like object: 2a0. which represents conceptually
     just a file name.  This means that no subdirectory paths should be
     included in the 'resource' argument.  This is because the location
     of the package the reader is for, acts as the “directory”.  Hence
     the metaphor for directories and file names is packages and
     resources, respectively.  This is also why instances of this class
     are expected to directly correlate to a specific package (instead
     of potentially representing multiple packages or a module).

     Loaders that wish to support resource reading are expected to
     provide a method called ‘get_resource_reader(fullname)’ which
     returns an object implementing this ABC’s interface.  If the module
     specified by fullname is not a package, this method should return
     *note None: 678.  An object compatible with this ABC should only be
     returned when the specified module is a package.

     Added in version 3.7.

     Deprecated since version 3.12, will be removed in version 3.14: Use
     *note importlib.resources.abc.TraversableResources: 2c5. instead.

      -- Method: abstractmethod open_resource (resource)

               Returns an opened, *note file-like object: 15f4. for
               binary reading of the 'resource'.

               If the resource cannot be found, *note FileNotFoundError:
               42e. is raised.

      -- Method: abstractmethod resource_path (resource)

               Returns the file system path to the 'resource'.

               If the resource does not concretely exist on the file
               system, raise *note FileNotFoundError: 42e.

      -- Method: abstractmethod is_resource (name)

               Returns ‘True’ if the named 'name' is considered a
               resource.  *note FileNotFoundError: 42e. is raised if
               'name' does not exist.

      -- Method: abstractmethod contents ()

               Returns an *note iterable: 126d. of strings over the
               contents of the package.  Do note that it is not required
               that all names returned by the iterator be actual
               resources, e.g.  it is acceptable to return names for
               which *note is_resource(): 479f. would be false.

               Allowing non-resource names to be returned is to allow
               for situations where how a package and its resources are
               stored are known a priori and the non-resource names
               would be useful.  For instance, returning subdirectory
               names is allowed so that when it is known that the
               package and resources are stored on the file system then
               those subdirectory names can be used directly.

               The abstract method returns an iterable of no items.

 -- Class: importlib.abc.Traversable

     An object with a subset of *note pathlib.Path: 229. methods
     suitable for traversing directories and opening files.

     For a representation of the object on the file-system, use *note
     importlib.resources.as_file(): 490.

     Added in version 3.9.

     Deprecated since version 3.12, will be removed in version 3.14: Use
     *note importlib.resources.abc.Traversable: 1f3. instead.

      -- Attribute: name

          Abstract.  The base name of this object without any parent
          references.

      -- Method: abstractmethod iterdir ()

          Yield ‘Traversable’ objects in ‘self’.

      -- Method: abstractmethod is_dir ()

          Return ‘True’ if ‘self’ is a directory.

      -- Method: abstractmethod is_file ()

          Return ‘True’ if ‘self’ is a file.

      -- Method: abstractmethod joinpath (child)

          Return Traversable child in ‘self’.

      -- Method: abstractmethod __truediv__ (child)

          Return ‘Traversable’ child in ‘self’.

      -- Method: abstractmethod open (mode='r', *args, **kwargs)

          'mode' may be ‘r’ or ‘rb’ to open as text or binary.  Return a
          handle suitable for reading (same as *note pathlib.Path.open:
          2992.).

          When opening as text, accepts encoding parameters such as
          those accepted by *note io.TextIOWrapper: 7bf.

      -- Method: read_bytes ()

          Read contents of ‘self’ as bytes.

      -- Method: read_text (encoding=None)

          Read contents of ‘self’ as text.

 -- Class: importlib.abc.TraversableResources

     An abstract base class for resource readers capable of serving the
     *note importlib.resources.files(): 491. interface.  Subclasses
     *note importlib.resources.abc.ResourceReader: 478f. and provides
     concrete implementations of the
     ‘importlib.resources.abc.ResourceReader’’s abstract methods.
     Therefore, any loader supplying *note
     importlib.abc.TraversableResources: 19cb. also supplies
     ResourceReader.

     Loaders that wish to support resource reading are expected to
     implement this interface.

     Added in version 3.9.

     Deprecated since version 3.12, will be removed in version 3.14: Use
     *note importlib.resources.abc.TraversableResources: 2c5. instead.

      -- Method: abstractmethod files ()

          Returns a *note importlib.resources.abc.Traversable: 1f3.
          object for the loaded package.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/importlib/abc.py

   (2) https://peps.python.org/pep-0302/

   (3) https://peps.python.org/pep-0302/

   (4) https://peps.python.org/pep-0302/

   (5) https://peps.python.org/pep-0302/


File: python.info,  Node: importlib machinery – Importers and path hooks,  Next: importlib util – Utility code for importers,  Prev: importlib abc – Abstract base classes related to import,  Up: importlib — The implementation of import

5.31.5.4 ‘importlib.machinery’ – Importers and path hooks
.........................................................

'Source code:' Lib/importlib/machinery.py(1)

__________________________________________________________________

This module contains the various objects that help *note import: 5e5.
find and load modules.

 -- Data: importlib.machinery.SOURCE_SUFFIXES

     A list of strings representing the recognized file suffixes for
     source modules.

     Added in version 3.3.

 -- Data: importlib.machinery.DEBUG_BYTECODE_SUFFIXES

     A list of strings representing the file suffixes for non-optimized
     bytecode modules.

     Added in version 3.3.

     Deprecated since version 3.5: Use *note BYTECODE_SUFFIXES: 519.
     instead.

 -- Data: importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES

     A list of strings representing the file suffixes for optimized
     bytecode modules.

     Added in version 3.3.

     Deprecated since version 3.5: Use *note BYTECODE_SUFFIXES: 519.
     instead.

 -- Data: importlib.machinery.BYTECODE_SUFFIXES

     A list of strings representing the recognized file suffixes for
     bytecode modules (including the leading dot).

     Added in version 3.3.

     Changed in version 3.5: The value is no longer dependent on
     ‘__debug__’.

 -- Data: importlib.machinery.EXTENSION_SUFFIXES

     A list of strings representing the recognized file suffixes for
     extension modules.

     Added in version 3.3.

 -- Function: importlib.machinery.all_suffixes ()

     Returns a combined list of strings representing all file suffixes
     for modules recognized by the standard import machinery.  This is a
     helper for code which simply needs to know if a filesystem path
     potentially refers to a module without needing any details on the
     kind of module (for example, *note inspect.getmodulename(): d61.).

     Added in version 3.3.

 -- Class: importlib.machinery.BuiltinImporter

     An *note importer: 21a8. for built-in modules.  All known built-in
     modules are listed in *note sys.builtin_module_names: 1dfd.  This
     class implements the *note importlib.abc.MetaPathFinder: 875. and
     *note importlib.abc.InspectLoader: f8d. ABCs.

     Only class methods are defined by this class to alleviate the need
     for instantiation.

     Changed in version 3.5: As part of PEP 489(2), the builtin importer
     now implements ‘Loader.create_module()’ and ‘Loader.exec_module()’

 -- Class: importlib.machinery.FrozenImporter

     An *note importer: 21a8. for frozen modules.  This class implements
     the *note importlib.abc.MetaPathFinder: 875. and *note
     importlib.abc.InspectLoader: f8d. ABCs.

     Only class methods are defined by this class to alleviate the need
     for instantiation.

     Changed in version 3.4: Gained ‘create_module()’ and
     ‘exec_module()’ methods.

 -- Class: importlib.machinery.WindowsRegistryFinder

     *note Finder: 20cd. for modules declared in the Windows registry.
     This class implements the *note importlib.abc.MetaPathFinder: 875.
     ABC.

     Only class methods are defined by this class to alleviate the need
     for instantiation.

     Added in version 3.3.

     Deprecated since version 3.6: Use *note site: c7. configuration
     instead.  Future versions of Python may not enable this finder by
     default.

 -- Class: importlib.machinery.PathFinder

     A *note Finder: 20cd. for *note sys.path: 3b7. and package
     ‘__path__’ attributes.  This class implements the *note
     importlib.abc.MetaPathFinder: 875. ABC.

     Only class methods are defined by this class to alleviate the need
     for instantiation.

      -- Method: classmethod find_spec (fullname, path=None,
               target=None)

          Class method that attempts to find a *note spec: 20c5. for the
          module specified by 'fullname' on *note sys.path: 3b7. or, if
          defined, on 'path'.  For each path entry that is searched,
          *note sys.path_importer_cache: 5e7. is checked.  If a
          non-false object is found then it is used as the *note path
          entry finder: 10af. to look for the module being searched for.
          If no entry is found in ‘sys.path_importer_cache’, then *note
          sys.path_hooks: 105f. is searched for a finder for the path
          entry and, if found, is stored in ‘sys.path_importer_cache’
          along with being queried about the module.  If no finder is
          ever found then ‘None’ is both stored in the cache and
          returned.

          Added in version 3.4.

          Changed in version 3.5: If the current working directory –
          represented by an empty string – is no longer valid then
          ‘None’ is returned but no value is cached in *note
          sys.path_importer_cache: 5e7.

      -- Method: classmethod invalidate_caches ()

          Calls *note importlib.abc.PathEntryFinder.invalidate_caches():
          478e. on all finders stored in *note sys.path_importer_cache:
          5e7. that define the method.  Otherwise entries in
          ‘sys.path_importer_cache’ set to ‘None’ are deleted.

          Changed in version 3.7: Entries of ‘None’ in *note
          sys.path_importer_cache: 5e7. are deleted.

     Changed in version 3.4: Calls objects in *note sys.path_hooks:
     105f. with the current working directory for ‘''’ (i.e.  the empty
     string).

 -- Class: importlib.machinery.FileFinder (path, *loader_details)

     A concrete implementation of *note importlib.abc.PathEntryFinder:
     876. which caches results from the file system.

     The 'path' argument is the directory for which the finder is in
     charge of searching.

     The 'loader_details' argument is a variable number of 2-item tuples
     each containing a loader and a sequence of file suffixes the loader
     recognizes.  The loaders are expected to be callables which accept
     two arguments of the module’s name and the path to the file found.

     The finder will cache the directory contents as necessary, making
     stat calls for each module search to verify the cache is not
     outdated.  Because cache staleness relies upon the granularity of
     the operating system’s state information of the file system, there
     is a potential race condition of searching for a module, creating a
     new file, and then searching for the module the new file
     represents.  If the operations happen fast enough to fit within the
     granularity of stat calls, then the module search will fail.  To
     prevent this from happening, when you create a module dynamically,
     make sure to call *note importlib.invalidate_caches(): c30.

     Added in version 3.3.

      -- Attribute: path

          The path the finder will search in.

      -- Method: find_spec (fullname, target=None)

          Attempt to find the spec to handle 'fullname' within *note
          path: 47ad.

          Added in version 3.4.

      -- Method: invalidate_caches ()

          Clear out the internal cache.

      -- Method: classmethod path_hook (*loader_details)

          A class method which returns a closure for use on *note
          sys.path_hooks: 105f.  An instance of ‘FileFinder’ is returned
          by the closure using the path argument given to the closure
          directly and 'loader_details' indirectly.

          If the argument to the closure is not an existing directory,
          *note ImportError: 41c. is raised.

 -- Class: importlib.machinery.SourceFileLoader (fullname, path)

     A concrete implementation of *note importlib.abc.SourceLoader:
     4798. by subclassing *note importlib.abc.FileLoader: 10b1. and
     providing some concrete implementations of other methods.

     Added in version 3.3.

      -- Attribute: name

          The name of the module that this loader will handle.

      -- Attribute: path

          The path to the source file.

      -- Method: is_package (fullname)

          Return ‘True’ if *note path: 47b1. appears to be for a
          package.

      -- Method: path_stats (path)

          Concrete implementation of *note
          importlib.abc.SourceLoader.path_stats(): 11ce.

      -- Method: set_data (path, data)

          Concrete implementation of *note
          importlib.abc.SourceLoader.set_data(): 4799.

      -- Method: load_module (name=None)

          Concrete implementation of *note
          importlib.abc.Loader.load_module(): 870. where specifying the
          name of the module to load is optional.

          Deprecated since version 3.6, will be removed in version 3.15:
          Use *note importlib.abc.Loader.exec_module(): 871. instead.

 -- Class: importlib.machinery.SourcelessFileLoader (fullname, path)

     A concrete implementation of *note importlib.abc.FileLoader: 10b1.
     which can import bytecode files (i.e.  no source code files exist).

     Please note that direct use of bytecode files (and thus not source
     code files) inhibits your modules from being usable by all Python
     implementations or new versions of Python which change the bytecode
     format.

     Added in version 3.3.

      -- Attribute: name

          The name of the module the loader will handle.

      -- Attribute: path

          The path to the bytecode file.

      -- Method: is_package (fullname)

          Determines if the module is a package based on *note path:
          47b6.

      -- Method: get_code (fullname)

          Returns the code object for *note name: 47b5. created from
          *note path: 47b6.

      -- Method: get_source (fullname)

          Returns ‘None’ as bytecode files have no source when this
          loader is used.

      -- Method: load_module (name=None)

     Concrete implementation of *note
     importlib.abc.Loader.load_module(): 870. where specifying the name
     of the module to load is optional.

     Deprecated since version 3.6, will be removed in version 3.15: Use
     *note importlib.abc.Loader.exec_module(): 871. instead.

 -- Class: importlib.machinery.ExtensionFileLoader (fullname, path)

     A concrete implementation of *note importlib.abc.ExecutionLoader:
     4792. for extension modules.

     The 'fullname' argument specifies the name of the module the loader
     is to support.  The 'path' argument is the path to the extension
     module’s file.

     Note that, by default, importing an extension module will fail in
     subinterpreters if it doesn’t implement multi-phase init (see PEP
     489(3)), even if it would otherwise import successfully.

     Added in version 3.3.

     Changed in version 3.12: Multi-phase init is now required for use
     in subinterpreters.

      -- Attribute: name

          Name of the module the loader supports.

      -- Attribute: path

          Path to the extension module.

      -- Method: create_module (spec)

          Creates the module object from the given specification in
          accordance with PEP 489(4).

          Added in version 3.5.

      -- Method: exec_module (module)

          Initializes the given module object in accordance with PEP
          489(5).

          Added in version 3.5.

      -- Method: is_package (fullname)

          Returns ‘True’ if the file path points to a package’s
          ‘__init__’ module based on *note EXTENSION_SUFFIXES: 518.

      -- Method: get_code (fullname)

          Returns ‘None’ as extension modules lack a code object.

      -- Method: get_source (fullname)

          Returns ‘None’ as extension modules do not have source code.

      -- Method: get_filename (fullname)

          Returns *note path: 47bb.

          Added in version 3.4.

 -- Class: importlib.machinery.NamespaceLoader (name, path, path_finder)

     A concrete implementation of *note importlib.abc.InspectLoader:
     f8d. for namespace packages.  This is an alias for a private class
     and is only made public for introspecting the ‘__loader__’
     attribute on namespace packages:

          >>> from importlib.machinery import NamespaceLoader
          >>> import my_namespace
          >>> isinstance(my_namespace.__loader__, NamespaceLoader)
          True
          >>> import importlib.abc
          >>> isinstance(my_namespace.__loader__, importlib.abc.Loader)
          True

     Added in version 3.11.

 -- Class: importlib.machinery.ModuleSpec (name, loader, *, origin=None,
          loader_state=None, is_package=None)

     A specification for a module’s import-system-related state.  This
     is typically exposed as the module’s *note __spec__: 20c6.
     attribute.  Many of these attributes are also available directly on
     a module: for example, ‘module.__spec__.origin == module.__file__’.
     Note, however, that while the 'values' are usually equivalent, they
     can differ since there is no synchronization between the two
     objects.  For example, it is possible to update the module’s *note
     __file__: 20cc. at runtime and this will not be automatically
     reflected in the module’s *note __spec__.origin: 47c1, and vice
     versa.

     Added in version 3.4.

      -- Attribute: name

          The module’s fully qualified name (see *note module.__name__:
          13d8.).  The *note finder: 20cd. should always set this
          attribute to a non-empty string.

      -- Attribute: loader

          The *note loader: 17c1. used to load the module (see *note
          module.__loader__: 2e2.).  The *note finder: 20cd. should
          always set this attribute.

      -- Attribute: origin

          The location the *note loader: 17c1. should use to load the
          module (see *note module.__file__: 20cc.).  For example, for
          modules loaded from a ‘.py’ file this is the filename.  The
          *note finder: 20cd. should always set this attribute to a
          meaningful value for the loader to use.  In the uncommon case
          that there is not one (like for namespace packages), it should
          be set to ‘None’.

      -- Attribute: submodule_search_locations

          A (possibly empty) *note sequence: 4f4. of strings enumerating
          the locations in which a package’s submodules will be found
          (see *note module.__path__: 1e0c.).  Most of the time there
          will only be a single directory in this list.

          The *note finder: 20cd. should set this attribute to a
          sequence, even an empty one, to indicate to the import system
          that the module is a package.  It should be set to ‘None’ for
          non-package modules.  It is set automatically later to a
          special object for namespace packages.

      -- Attribute: loader_state

          The *note finder: 20cd. may set this attribute to an object
          containing additional, module-specific data to use when
          loading the module.  Otherwise it should be set to ‘None’.

      -- Attribute: cached

          The filename of a compiled version of the module’s code (see
          *note module.__cached__: 2d5.).  The *note finder: 20cd.
          should always set this attribute but it may be ‘None’ for
          modules that do not need compiled code stored.

      -- Attribute: parent

          (Read-only) The fully qualified name of the package the module
          is in (or the empty string for a top-level module).  See *note
          module.__package__: 2d7.  If the module is a package then this
          is the same as *note name: 20c7.

      -- Attribute: has_location

          ‘True’ if the spec’s *note origin: 47c1. refers to a loadable
          location, ‘False’ otherwise.  This value impacts how ‘origin’
          is interpreted and how the module’s *note __file__: 20cc. is
          populated.

 -- Class: importlib.machinery.AppleFrameworkLoader (name, path)

     A specialization of *note importlib.machinery.ExtensionFileLoader:
     cd6. that is able to load extension modules in Framework format.

     For compatibility with the iOS App Store, 'all' binary modules in
     an iOS app must be dynamic libraries, contained in a framework with
     appropriate metadata, stored in the ‘Frameworks’ folder of the
     packaged app.  There can be only a single binary per framework, and
     there can be no executable binary material outside the Frameworks
     folder.

     To accommodate this requirement, when running on iOS, extension
     module binaries are 'not' packaged as ‘.so’ files on ‘sys.path’,
     but as individual standalone frameworks.  To discover those
     frameworks, this loader is registered against the ‘.fwork’ file
     extension, with a ‘.fwork’ file acting as a placeholder in the
     original location of the binary on ‘sys.path’.  The ‘.fwork’ file
     contains the path of the actual binary in the ‘Frameworks’ folder,
     relative to the app bundle.  To allow for resolving a
     framework-packaged binary back to the original location, the
     framework is expected to contain a ‘.origin’ file that contains the
     location of the ‘.fwork’ file, relative to the app bundle.

     For example, consider the case of an import ‘from foo.bar import
     _whiz’, where ‘_whiz’ is implemented with the binary module
     ‘sources/foo/bar/_whiz.abi3.so’, with ‘sources’ being the location
     registered on ‘sys.path’, relative to the application bundle.  This
     module 'must' be distributed as
     ‘Frameworks/foo.bar._whiz.framework/foo.bar._whiz’ (creating the
     framework name from the full import path of the module), with an
     ‘Info.plist’ file in the ‘.framework’ directory identifying the
     binary as a framework.  The ‘foo.bar._whiz’ module would be
     represented in the original location with a
     ‘sources/foo/bar/_whiz.abi3.fwork’ marker file, containing the path
     ‘Frameworks/foo.bar._whiz/foo.bar._whiz’.  The framework would also
     contain ‘Frameworks/foo.bar._whiz.framework/foo.bar._whiz.origin’,
     containing the path to the ‘.fwork’ file.

     When a module is loaded with this loader, the ‘__file__’ for the
     module will report as the location of the ‘.fwork’ file.  This
     allows code to use the ‘__file__’ of a module as an anchor for file
     system traveral.  However, the spec origin will reference the
     location of the 'actual' binary in the ‘.framework’ folder.

     The Xcode project building the app is responsible for converting
     any ‘.so’ files from wherever they exist in the ‘PYTHONPATH’ into
     frameworks in the ‘Frameworks’ folder (including stripping
     extensions from the module file, the addition of framework
     metadata, and signing the resulting framework), and creating the
     ‘.fwork’ and ‘.origin’ files.  This will usually be done with a
     build step in the Xcode project; see the iOS documentation for
     details on how to construct this build step.

     Added in version 3.13.

     *note Availability: 1ef7.: iOS.

      -- Attribute: name

          Name of the module the loader supports.

      -- Attribute: path

          Path to the ‘.fwork’ file for the extension module.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/importlib/machinery.py

   (2) https://peps.python.org/pep-0489/

   (3) https://peps.python.org/pep-0489/

   (4) https://peps.python.org/pep-0489/

   (5) https://peps.python.org/pep-0489/


File: python.info,  Node: importlib util – Utility code for importers,  Next: Examples<34>,  Prev: importlib machinery – Importers and path hooks,  Up: importlib — The implementation of import

5.31.5.5 ‘importlib.util’ – Utility code for importers
......................................................

'Source code:' Lib/importlib/util.py(1)

__________________________________________________________________

This module contains the various objects that help in the construction
of an *note importer: 21a8.

 -- Data: importlib.util.MAGIC_NUMBER

     The bytes which represent the bytecode version number.  If you need
     help with loading/writing bytecode then consider *note
     importlib.abc.SourceLoader: 4798.

     Added in version 3.4.

 -- Function: importlib.util.cache_from_source (path,
          debug_override=None, *, optimization=None)

     Return the PEP 3147(2)/ PEP 488(3) path to the byte-compiled file
     associated with the source 'path'.  For example, if 'path' is
     ‘/foo/bar/baz.py’ the return value would be
     ‘/foo/bar/__pycache__/baz.cpython-32.pyc’ for Python 3.2.  The
     ‘cpython-32’ string comes from the current magic tag (see
     ‘get_tag()’; if ‘sys.implementation.cache_tag’ is not defined then
     *note NotImplementedError: 228. will be raised).

     The 'optimization' parameter is used to specify the optimization
     level of the bytecode file.  An empty string represents no
     optimization, so ‘/foo/bar/baz.py’ with an 'optimization' of ‘''’
     will result in a bytecode path of
     ‘/foo/bar/__pycache__/baz.cpython-32.pyc’.  ‘None’ causes the
     interpreter’s optimization level to be used.  Any other value’s
     string representation is used, so ‘/foo/bar/baz.py’ with an
     'optimization' of ‘2’ will lead to the bytecode path of
     ‘/foo/bar/__pycache__/baz.cpython-32.opt-2.pyc’.  The string
     representation of 'optimization' can only be alphanumeric, else
     *note ValueError: 202. is raised.

     The 'debug_override' parameter is deprecated and can be used to
     override the system’s value for ‘__debug__’.  A ‘True’ value is the
     equivalent of setting 'optimization' to the empty string.  A
     ‘False’ value is the same as setting 'optimization' to ‘1’.  If
     both 'debug_override' an 'optimization' are not ‘None’ then *note
     TypeError: 2c3. is raised.

     Added in version 3.4.

     Changed in version 3.5: The 'optimization' parameter was added and
     the 'debug_override' parameter was deprecated.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: importlib.util.source_from_cache (path)

     Given the 'path' to a PEP 3147(4) file name, return the associated
     source code file path.  For example, if 'path' is
     ‘/foo/bar/__pycache__/baz.cpython-32.pyc’ the returned path would
     be ‘/foo/bar/baz.py’.  'path' need not exist, however if it does
     not conform to PEP 3147(5) or PEP 488(6) format, a *note
     ValueError: 202. is raised.  If ‘sys.implementation.cache_tag’ is
     not defined, *note NotImplementedError: 228. is raised.

     Added in version 3.4.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: importlib.util.decode_source (source_bytes)

     Decode the given bytes representing source code and return it as a
     string with universal newlines (as required by *note
     importlib.abc.InspectLoader.get_source(): f91.).

     Added in version 3.4.

 -- Function: importlib.util.resolve_name (name, package)

     Resolve a relative module name to an absolute one.

     If 'name' has no leading dots, then 'name' is simply returned.
     This allows for usage such as ‘importlib.util.resolve_name('sys',
     __spec__.parent)’ without doing a check to see if the 'package'
     argument is needed.

     *note ImportError: 41c. is raised if 'name' is a relative module
     name but 'package' is a false value (e.g.  ‘None’ or the empty
     string).  ‘ImportError’ is also raised if a relative name would
     escape its containing package (e.g.  requesting ‘..bacon’ from
     within the ‘spam’ package).

     Added in version 3.3.

     Changed in version 3.9: To improve consistency with import
     statements, raise *note ImportError: 41c. instead of *note
     ValueError: 202. for invalid relative import attempts.

 -- Function: importlib.util.find_spec (name, package=None)

     Find the *note spec: 20c5. for a module, optionally relative to the
     specified 'package' name.  If the module is in *note sys.modules:
     1655, then ‘sys.modules[name].__spec__’ is returned (unless the
     spec would be ‘None’ or is not set, in which case *note ValueError:
     202. is raised).  Otherwise a search using *note sys.meta_path:
     d53. is done.  ‘None’ is returned if no spec is found.

     If 'name' is for a submodule (contains a dot), the parent module is
     automatically imported.

     'name' and 'package' work the same as for ‘import_module()’.

     Added in version 3.4.

     Changed in version 3.7: Raises *note ModuleNotFoundError: b61.
     instead of *note AttributeError: 34e. if 'package' is in fact not a
     package (i.e.  lacks a *note __path__: 1e0c. attribute).

 -- Function: importlib.util.module_from_spec (spec)

     Create a new module based on 'spec' and *note
     spec.loader.create_module: cd4.

     If *note spec.loader.create_module: cd4. does not return ‘None’,
     then any pre-existing attributes will not be reset.  Also, no *note
     AttributeError: 34e. will be raised if triggered while accessing
     'spec' or setting an attribute on the module.

     This function is preferred over using *note types.ModuleType: e45.
     to create a new module as 'spec' is used to set as many
     import-controlled attributes on the module as possible.

     Added in version 3.5.

 -- Function: importlib.util.spec_from_loader (name, loader, *,
          origin=None, is_package=None)

     A factory function for creating a *note ModuleSpec: 200d. instance
     based on a loader.  The parameters have the same meaning as they do
     for ModuleSpec.  The function uses available *note loader: 17c1.
     APIs, such as ‘InspectLoader.is_package()’, to fill in any missing
     information on the spec.

     Added in version 3.4.

 -- Function: importlib.util.spec_from_file_location (name, location, *,
          loader=None, submodule_search_locations=None)

     A factory function for creating a *note ModuleSpec: 200d. instance
     based on the path to a file.  Missing information will be filled in
     on the spec by making use of loader APIs and by the implication
     that the module will be file-based.

     Added in version 3.4.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- Function: importlib.util.source_hash (source_bytes)

     Return the hash of 'source_bytes' as bytes.  A hash-based ‘.pyc’
     file embeds the ‘source_hash()’ of the corresponding source file’s
     contents in its header.

     Added in version 3.7.

 -- Function: importlib.util._incompatible_extension_module_restrictions
          (*, disable_check)

     A context manager that can temporarily skip the compatibility check
     for extension modules.  By default the check is enabled and will
     fail when a single-phase init module is imported in a
     subinterpreter.  It will also fail for a multi-phase init module
     that doesn’t explicitly support a per-interpreter GIL, when
     imported in an interpreter with its own GIL.

     Note that this function is meant to accommodate an unusual case;
     one which is likely to eventually go away.  There’s is a pretty
     good chance this is not what you were looking for.

     You can get the same effect as this function by implementing the
     basic interface of multi-phase init ( PEP 489(7)) and lying about
     support for multiple interpreters (or per-interpreter GIL).

          Warning: Using this function to disable the check can lead to
          unexpected behavior and even crashes.  It should only be used
          during extension module development.

     Added in version 3.12.

 -- Class: importlib.util.LazyLoader (loader)

     A class which postpones the execution of the loader of a module
     until the module has an attribute accessed.

     This class 'only' works with loaders that define *note
     exec_module(): 871. as control over what module type is used for
     the module is required.  For those same reasons, the loader’s *note
     create_module(): cd4. method must return ‘None’ or a type for which
     its ‘__class__’ attribute can be mutated along with not using *note
     slots: 5e2.  Finally, modules which substitute the object placed
     into *note sys.modules: 1655. will not work as there is no way to
     properly replace the module references throughout the interpreter
     safely; *note ValueError: 202. is raised if such a substitution is
     detected.

          Note: For projects where startup time is critical, this class
          allows for potentially minimizing the cost of loading a module
          if it is never used.  For projects where startup time is not
          essential then use of this class is 'heavily' discouraged due
          to error messages created during loading being postponed and
          thus occurring out of context.

     Added in version 3.5.

     Changed in version 3.6: Began calling *note create_module(): cd4,
     removing the compatibility warning for *note
     importlib.machinery.BuiltinImporter: cd5. and *note
     importlib.machinery.ExtensionFileLoader: cd6.

      -- Method: classmethod factory (loader)

          A class method which returns a callable that creates a lazy
          loader.  This is meant to be used in situations where the
          loader is passed by class instead of by instance.

               suffixes = importlib.machinery.SOURCE_SUFFIXES
               loader = importlib.machinery.SourceFileLoader
               lazy_loader = importlib.util.LazyLoader.factory(loader)
               finder = importlib.machinery.FileFinder(path, (lazy_loader, suffixes))

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/importlib/util.py

   (2) https://peps.python.org/pep-3147/

   (3) https://peps.python.org/pep-0488/

   (4) https://peps.python.org/pep-3147/

   (5) https://peps.python.org/pep-3147/

   (6) https://peps.python.org/pep-0488/

   (7) https://peps.python.org/pep-0489/


File: python.info,  Node: Examples<34>,  Prev: importlib util – Utility code for importers,  Up: importlib — The implementation of import

5.31.5.6 Examples
.................

* Menu:

* Importing programmatically::
* Checking if a module can be imported::
* Importing a source file directly::
* Implementing lazy imports::
* Setting up an importer::
* Approximating importlib.import_module(): Approximating importlib import_module.


File: python.info,  Node: Importing programmatically,  Next: Checking if a module can be imported,  Up: Examples<34>

5.31.5.7 Importing programmatically
...................................

To programmatically import a module, use *note
importlib.import_module(): 51b.

     import importlib

     itertools = importlib.import_module('itertools')


File: python.info,  Node: Checking if a module can be imported,  Next: Importing a source file directly,  Prev: Importing programmatically,  Up: Examples<34>

5.31.5.8 Checking if a module can be imported
.............................................

If you need to find out if a module can be imported without actually
doing the import, then you should use *note importlib.util.find_spec():
2cd.

Note that if ‘name’ is a submodule (contains a dot), *note
importlib.util.find_spec(): 2cd. will import the parent module.

     import importlib.util
     import sys

     # For illustrative purposes.
     name = 'itertools'

     if name in sys.modules:
         print(f"{name!r} already in sys.modules")
     elif (spec := importlib.util.find_spec(name)) is not None:
         # If you chose to perform the actual import ...
         module = importlib.util.module_from_spec(spec)
         sys.modules[name] = module
         spec.loader.exec_module(module)
         print(f"{name!r} has been imported")
     else:
         print(f"can't find the {name!r} module")


File: python.info,  Node: Importing a source file directly,  Next: Implementing lazy imports,  Prev: Checking if a module can be imported,  Up: Examples<34>

5.31.5.9 Importing a source file directly
.........................................

This recipe should be used with caution: it is an approximation of an
import statement where the file path is specified directly, rather than
*note sys.path: 3b7. being searched.  Alternatives should first be
considered first, such as modifying ‘sys.path’ when a proper module is
required, or using *note runpy.run_path(): 181. when the global
namespace resulting from running a Python file is appropriate.

To import a Python source file directly from a path, use the following
recipe:

     import importlib.util
     import sys


     def import_from_path(module_name, file_path):
         spec = importlib.util.spec_from_file_location(module_name, file_path)
         module = importlib.util.module_from_spec(spec)
         sys.modules[module_name] = module
         spec.loader.exec_module(module)
         return module


     # For illustrative purposes only (use of `json` is arbitrary).
     import json
     file_path = json.__file__
     module_name = json.__name__

     # Similar outcome as `import json`.
     json = import_from_path(module_name, file_path)


File: python.info,  Node: Implementing lazy imports,  Next: Setting up an importer,  Prev: Importing a source file directly,  Up: Examples<34>

5.31.5.10 Implementing lazy imports
...................................

The example below shows how to implement lazy imports:

     >>> import importlib.util
     >>> import sys
     >>> def lazy_import(name):
     ...     spec = importlib.util.find_spec(name)
     ...     loader = importlib.util.LazyLoader(spec.loader)
     ...     spec.loader = loader
     ...     module = importlib.util.module_from_spec(spec)
     ...     sys.modules[name] = module
     ...     loader.exec_module(module)
     ...     return module
     ...
     >>> lazy_typing = lazy_import("typing")
     >>> #lazy_typing is a real module object,
     >>> #but it is not loaded in memory yet.
     >>> lazy_typing.TYPE_CHECKING
     False


File: python.info,  Node: Setting up an importer,  Next: Approximating importlib import_module,  Prev: Implementing lazy imports,  Up: Examples<34>

5.31.5.11 Setting up an importer
................................

For deep customizations of import, you typically want to implement an
*note importer: 21a8.  This means managing both the *note finder: 20cd.
and *note loader: 17c1. side of things.  For finders there are two
flavours to choose from depending on your needs: a *note meta path
finder: 10ae. or a *note path entry finder: 10af.  The former is what
you would put on *note sys.meta_path: d53. while the latter is what you
create using a *note path entry hook: 21b9. on *note sys.path_hooks:
105f. which works with *note sys.path: 3b7. entries to potentially
create a finder.  This example will show you how to register your own
importers so that import will use them (for creating an importer for
yourself, read the documentation for the appropriate classes defined
within this package):

     import importlib.machinery
     import sys

     # For illustrative purposes only.
     SpamMetaPathFinder = importlib.machinery.PathFinder
     SpamPathEntryFinder = importlib.machinery.FileFinder
     loader_details = (importlib.machinery.SourceFileLoader,
                       importlib.machinery.SOURCE_SUFFIXES)

     # Setting up a meta path finder.
     # Make sure to put the finder in the proper location in the list in terms of
     # priority.
     sys.meta_path.append(SpamMetaPathFinder)

     # Setting up a path entry finder.
     # Make sure to put the path hook in the proper location in the list in terms
     # of priority.
     sys.path_hooks.append(SpamPathEntryFinder.path_hook(loader_details))


File: python.info,  Node: Approximating importlib import_module,  Prev: Setting up an importer,  Up: Examples<34>

5.31.5.12 Approximating ‘importlib.import_module()’
...................................................

Import itself is implemented in Python code, making it possible to
expose most of the import machinery through importlib.  The following
helps illustrate the various APIs that importlib exposes by providing an
approximate implementation of *note importlib.import_module(): 51b.:

     import importlib.util
     import sys

     def import_module(name, package=None):
         """An approximate implementation of import."""
         absolute_name = importlib.util.resolve_name(name, package)
         try:
             return sys.modules[absolute_name]
         except KeyError:
             pass

         path = None
         if '.' in absolute_name:
             parent_name, _, child_name = absolute_name.rpartition('.')
             parent_module = import_module(parent_name)
             path = parent_module.__spec__.submodule_search_locations
         for finder in sys.meta_path:
             spec = finder.find_spec(absolute_name, path)
             if spec is not None:
                 break
         else:
             msg = f'No module named {absolute_name!r}'
             raise ModuleNotFoundError(msg, name=absolute_name)
         module = importlib.util.module_from_spec(spec)
         sys.modules[absolute_name] = module
         spec.loader.exec_module(module)
         if path is not None:
             setattr(parent_module, child_name, module)
         return module


File: python.info,  Node: importlib resources – Package resource reading opening and access,  Next: importlib resources abc – Abstract base classes for resources,  Prev: importlib — The implementation of import,  Up: Importing Modules

5.31.6 ‘importlib.resources’ – Package resource reading, opening and access
---------------------------------------------------------------------------

'Source code:' Lib/importlib/resources/__init__.py(1)

__________________________________________________________________

Added in version 3.7.

This module leverages Python’s import system to provide access to
'resources' within 'packages'.

“Resources” are file-like resources associated with a module or package
in Python.  The resources may be contained directly in a package, within
a subdirectory contained in that package, or adjacent to modules outside
a package.  Resources may be text or binary.  As a result, a package’s
Python module sources (.py), compilation artifacts (pycache), and
installation artifacts (like *note reserved filenames: 223. in
directories) are technically de-facto resources of that package.  In
practice, however, resources are primarily those non-Python artifacts
exposed specifically by the package author.

Resources can be opened or read in either binary or text mode.

Resources are roughly akin to files inside directories, though it’s
important to keep in mind that this is just a metaphor.  Resources and
packages 'do not' have to exist as physical files and directories on the
file system: for example, a package and its resources can be imported
from a zip file using *note zipimport: 132.

     Note: This module provides functionality similar to
     pkg_resources(2) Basic Resource Access(3) without the performance
     overhead of that package.  This makes reading resources included in
     packages easier, with more stable and consistent semantics.

     The standalone backport of this module provides more information on
     using importlib.resources(4) and migrating from pkg_resources to
     importlib.resources(5).

*note Loaders: efb. that wish to support resource reading should
implement a ‘get_resource_reader(fullname)’ method as specified by *note
importlib.resources.abc.ResourceReader: 478f.

 -- Class: importlib.resources.Anchor

     Represents an anchor for resources, either a *note module object:
     e45. or a module name as a string.  Defined as ‘Union[str,
     ModuleType]’.

 -- Function: importlib.resources.files (anchor: Anchor | None = None)

     Returns a *note Traversable: 1f3. object representing the resource
     container (think directory) and its resources (think files).  A
     Traversable may contain other containers (think subdirectories).

     'anchor' is an optional *note Anchor: 47d4.  If the anchor is a
     package, resources are resolved from that package.  If a module,
     resources are resolved adjacent to that module (in the same package
     or the package root).  If the anchor is omitted, the caller’s
     module is used.

     Added in version 3.9.

     Changed in version 3.12: 'package' parameter was renamed to
     'anchor'.  'anchor' can now be a non-package module and if omitted
     will default to the caller’s module.  'package' is still accepted
     for compatibility but will raise a *note DeprecationWarning: 1a5.
     Consider passing the anchor positionally or using
     ‘importlib_resources >= 5.10’ for a compatible interface on older
     Pythons.

 -- Function: importlib.resources.as_file (traversable)

     Given a *note Traversable: 1f3. object representing a file or
     directory, typically from *note importlib.resources.files(): 491,
     return a context manager for use in a *note with: 5d5. statement.
     The context manager provides a *note pathlib.Path: 229. object.

     Exiting the context manager cleans up any temporary file or
     directory created when the resource was extracted from e.g.  a zip
     file.

     Use ‘as_file’ when the Traversable methods (‘read_text’, etc) are
     insufficient and an actual file or directory on the file system is
     required.

     Added in version 3.9.

     Changed in version 3.12: Added support for 'traversable'
     representing a directory.

* Menu:

* Functional API::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/importlib/resources/__init__.py

   (2) https://setuptools.readthedocs.io/en/latest/pkg_resources.html

   (3) 
https://setuptools.readthedocs.io/en/latest/pkg_resources.html#basic-resource-access

   (4) https://importlib-resources.readthedocs.io/en/latest/using.html

   (5) 
https://importlib-resources.readthedocs.io/en/latest/migration.html


File: python.info,  Node: Functional API,  Up: importlib resources – Package resource reading opening and access

5.31.6.1 Functional API
.......................

A set of simplified, backwards-compatible helpers is available.  These
allow common operations in a single function call.

For all the following functions:

   - 'anchor' is an *note Anchor: 47d4, as in *note files(): 491.
     Unlike in ‘files’, it may not be omitted.

   - 'path_names' are components of a resource’s path name, relative to
     the anchor.  For example, to get the text of resource named
     ‘info.txt’, use:

          importlib.resources.read_text(my_module, "info.txt")

     Like *note Traversable.joinpath: 1f3, The individual components
     should use forward slashes (‘/’) as path separators.  For example,
     the following are equivalent:

          importlib.resources.read_binary(my_module, "pics/painting.png")
          importlib.resources.read_binary(my_module, "pics", "painting.png")

     For backward compatibility reasons, functions that read text
     require an explicit 'encoding' argument if multiple 'path_names'
     are given.  For example, to get the text of ‘info/chapter1.txt’,
     use:

          importlib.resources.read_text(my_module, "info", "chapter1.txt",
                                        encoding='utf-8')

 -- Function: importlib.resources.open_binary (anchor, *path_names)

     Open the named resource for binary reading.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.

     This function returns a *note BinaryIO: 41e6. object, that is, a
     binary stream open for reading.

     This function is roughly equivalent to:

          files(anchor).joinpath(*path_names).open('rb')

     Changed in version 3.13: Multiple 'path_names' are accepted.

 -- Function: importlib.resources.open_text (anchor, *path_names,
          encoding='utf-8', errors='strict')

     Open the named resource for text reading.  By default, the contents
     are read as strict UTF-8.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.  'encoding' and 'errors' have the same meaning as in
     built-in *note open(): 51f.

     For backward compatibility reasons, the 'encoding' argument must be
     given explicitly if there are multiple 'path_names'.  This
     limitation is scheduled to be removed in Python 3.15.

     This function returns a *note TextIO: 41e5. object, that is, a text
     stream open for reading.

     This function is roughly equivalent to:

          files(anchor).joinpath(*path_names).open('r', encoding=encoding)

     Changed in version 3.13: Multiple 'path_names' are accepted.
     'encoding' and 'errors' must be given as keyword arguments.

 -- Function: importlib.resources.read_binary (anchor, *path_names)

     Read and return the contents of the named resource as *note bytes:
     1c2.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.

     This function is roughly equivalent to:

          files(anchor).joinpath(*path_names).read_bytes()

     Changed in version 3.13: Multiple 'path_names' are accepted.

 -- Function: importlib.resources.read_text (anchor, *path_names,
          encoding='utf-8', errors='strict')

     Read and return the contents of the named resource as *note str:
     44f.  By default, the contents are read as strict UTF-8.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.  'encoding' and 'errors' have the same meaning as in
     built-in *note open(): 51f.

     For backward compatibility reasons, the 'encoding' argument must be
     given explicitly if there are multiple 'path_names'.  This
     limitation is scheduled to be removed in Python 3.15.

     This function is roughly equivalent to:

          files(anchor).joinpath(*path_names).read_text(encoding=encoding)

     Changed in version 3.13: Multiple 'path_names' are accepted.
     'encoding' and 'errors' must be given as keyword arguments.

 -- Function: importlib.resources.path (anchor, *path_names)

     Provides the path to the 'resource' as an actual file system path.
     This function returns a context manager for use in a *note with:
     5d5. statement.  The context manager provides a *note pathlib.Path:
     229. object.

     Exiting the context manager cleans up any temporary files created,
     e.g.  when the resource needs to be extracted from a zip file.

     For example, the *note stat(): 829. method requires an actual file
     system path; it can be used like this:

          with importlib.resources.path(anchor, "resource.txt") as fspath:
              result = fspath.stat()

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.

     This function is roughly equivalent to:

          as_file(files(anchor).joinpath(*path_names))

     Changed in version 3.13: Multiple 'path_names' are accepted.
     'encoding' and 'errors' must be given as keyword arguments.

 -- Function: importlib.resources.is_resource (anchor, *path_names)

     Return ‘True’ if the named resource exists, otherwise ‘False’.
     This function does not consider directories to be resources.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.

     This function is roughly equivalent to:

          files(anchor).joinpath(*path_names).is_file()

     Changed in version 3.13: Multiple 'path_names' are accepted.

 -- Function: importlib.resources.contents (anchor, *path_names)

     Return an iterable over the named items within the package or path.
     The iterable returns names of resources (e.g.  files) and
     non-resources (e.g.  directories) as *note str: 44f.  The iterable
     does not recurse into subdirectories.

     See *note the introduction: 47d6. for details on 'anchor' and
     'path_names'.

     This function is roughly equivalent to:

          for resource in files(anchor).joinpath(*path_names).iterdir():
              yield resource.name

     Deprecated since version 3.11: Prefer ‘iterdir()’ as above, which
     offers more control over the results and richer functionality.


File: python.info,  Node: importlib resources abc – Abstract base classes for resources,  Next: importlib metadata – Accessing package metadata,  Prev: importlib resources – Package resource reading opening and access,  Up: Importing Modules

5.31.7 ‘importlib.resources.abc’ – Abstract base classes for resources
----------------------------------------------------------------------

'Source code:' Lib/importlib/resources/abc.py(1)

__________________________________________________________________

Added in version 3.11.

 -- Class: importlib.resources.abc.ResourceReader

     'Superseded by TraversableResources'

     An *note abstract base class: 11fa. to provide the ability to read
     'resources'.

     From the perspective of this ABC, a 'resource' is a binary artifact
     that is shipped within a package.  Typically this is something like
     a data file that lives next to the ‘__init__.py’ file of the
     package.  The purpose of this class is to help abstract out the
     accessing of such data files so that it does not matter if the
     package and its data file(s) are stored e.g.  in a zip file versus
     on the file system.

     For any of methods of this class, a 'resource' argument is expected
     to be a *note path-like object: 2a0. which represents conceptually
     just a file name.  This means that no subdirectory paths should be
     included in the 'resource' argument.  This is because the location
     of the package the reader is for, acts as the “directory”.  Hence
     the metaphor for directories and file names is packages and
     resources, respectively.  This is also why instances of this class
     are expected to directly correlate to a specific package (instead
     of potentially representing multiple packages or a module).

     Loaders that wish to support resource reading are expected to
     provide a method called ‘get_resource_reader(fullname)’ which
     returns an object implementing this ABC’s interface.  If the module
     specified by fullname is not a package, this method should return
     *note None: 678.  An object compatible with this ABC should only be
     returned when the specified module is a package.

     Deprecated since version 3.12: Use *note
     importlib.resources.abc.TraversableResources: 2c5. instead.

      -- Method: abstractmethod open_resource (resource)

          Returns an opened, *note file-like object: 15f4. for binary
          reading of the 'resource'.

          If the resource cannot be found, *note FileNotFoundError: 42e.
          is raised.

      -- Method: abstractmethod resource_path (resource)

          Returns the file system path to the 'resource'.

          If the resource does not concretely exist on the file system,
          raise *note FileNotFoundError: 42e.

      -- Method: abstractmethod is_resource (path)

          Returns ‘True’ if the named 'path' is considered a resource.
          *note FileNotFoundError: 42e. is raised if 'path' does not
          exist.

          Changed in version 3.10: The argument 'name' was renamed to
          'path'.

      -- Method: abstractmethod contents ()

          Returns an *note iterable: 126d. of strings over the contents
          of the package.  Do note that it is not required that all
          names returned by the iterator be actual resources, e.g.  it
          is acceptable to return names for which *note is_resource():
          47dc. would be false.

          Allowing non-resource names to be returned is to allow for
          situations where how a package and its resources are stored
          are known a priori and the non-resource names would be useful.
          For instance, returning subdirectory names is allowed so that
          when it is known that the package and resources are stored on
          the file system then those subdirectory names can be used
          directly.

          The abstract method returns an iterable of no items.

 -- Class: importlib.resources.abc.Traversable

     An object with a subset of *note pathlib.Path: 229. methods
     suitable for traversing directories and opening files.

     For a representation of the object on the file-system, use *note
     importlib.resources.as_file(): 490.

      -- Attribute: name

          Abstract.  The base name of this object without any parent
          references.

      -- Method: abstractmethod iterdir ()

          Yield Traversable objects in self.

      -- Method: abstractmethod is_dir ()

          Return ‘True’ if self is a directory.

      -- Method: abstractmethod is_file ()

          Return ‘True’ if self is a file.

      -- Method: abstractmethod joinpath (*pathsegments)

          Traverse directories according to 'pathsegments' and return
          the result as ‘Traversable’.

          Each 'pathsegments' argument may contain multiple names
          separated by forward slashes (‘/’, ‘posixpath.sep’ ).  For
          example, the following are equivalent:

               files.joinpath('subdir', 'subsuddir', 'file.txt')
               files.joinpath('subdir/subsuddir/file.txt')

          Note that some ‘Traversable’ implementations might not be
          updated to the latest version of the protocol.  For
          compatibility with such implementations, provide a single
          argument without path separators to each call to ‘joinpath’.
          For example:

               files.joinpath('subdir').joinpath('subsubdir').joinpath('file.txt')

          Changed in version 3.11: ‘joinpath’ accepts multiple
          'pathsegments', and these segments may contain forward slashes
          as path separators.  Previously, only a single 'child'
          argument was accepted.

      -- Method: abstractmethod __truediv__ (child)

          Return Traversable child in self.  Equivalent to
          ‘joinpath(child)’.

      -- Method: abstractmethod open (mode='r', *args, **kwargs)

          'mode' may be ‘r’ or ‘rb’ to open as text or binary.  Return a
          handle suitable for reading (same as *note pathlib.Path.open:
          2992.).

          When opening as text, accepts encoding parameters such as
          those accepted by *note io.TextIOWrapper: 7bf.

      -- Method: read_bytes ()

          Read contents of self as bytes.

      -- Method: read_text (encoding=None)

          Read contents of self as text.

 -- Class: importlib.resources.abc.TraversableResources

     An abstract base class for resource readers capable of serving the
     *note importlib.resources.files(): 491. interface.  Subclasses
     *note ResourceReader: 478f. and provides concrete implementations
     of the ‘ResourceReader’’s abstract methods.  Therefore, any loader
     supplying ‘TraversableResources’ also supplies ‘ResourceReader’.

     Loaders that wish to support resource reading are expected to
     implement this interface.

      -- Method: abstractmethod files ()

          Returns a *note importlib.resources.abc.Traversable: 1f3.
          object for the loaded package.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/importlib/resources/abc.py


File: python.info,  Node: importlib metadata – Accessing package metadata,  Next: The initialization of the sys path module search path,  Prev: importlib resources abc – Abstract base classes for resources,  Up: Importing Modules

5.31.8 ‘importlib.metadata’ – Accessing package metadata
--------------------------------------------------------

Added in version 3.8.

Changed in version 3.10: ‘importlib.metadata’ is no longer provisional.

'Source code:' Lib/importlib/metadata/__init__.py(1)

‘importlib.metadata’ is a library that provides access to the metadata
of an installed Distribution Package(2), such as its entry points or its
top-level names (Import Package(3)s, modules, if any).  Built in part on
Python’s import system, this library intends to replace similar
functionality in the entry point API(4) and metadata API(5) of
‘pkg_resources’.  Along with *note importlib.resources: 7b, this package
can eliminate the need to use the older and less efficient
‘pkg_resources’ package.

‘importlib.metadata’ operates on third-party 'distribution packages'
installed into Python’s ‘site-packages’ directory via tools such as
pip(6).  Specifically, it works with distributions with discoverable
‘dist-info’ or ‘egg-info’ directories, and metadata defined by the Core
metadata specifications(7).

     Important: These are 'not' necessarily equivalent to or correspond
     1:1 with the top-level 'import package' names that can be imported
     inside Python code.  One 'distribution package' can contain
     multiple 'import packages' (and single modules), and one top-level
     'import package' may map to multiple 'distribution packages' if it
     is a namespace package.  You can use *note
     packages_distributions(): 816. to get a mapping between them.

By default, distribution metadata can live on the file system or in zip
archives on *note sys.path: 3b7.  Through an extension mechanism, the
metadata can live almost anywhere.

See also
........

‘https://importlib-metadata.readthedocs.io/’

     The documentation for ‘importlib_metadata’, which supplies a
     backport of ‘importlib.metadata’.  This includes an API
     reference(8) for this module’s classes and functions, as well as a
     migration guide(9) for existing users of ‘pkg_resources’.

* Menu:

* Overview: Overview<3>.
* Functional API: Functional API<2>.
* Distributions::
* Distribution Discovery::
* Extending the search algorithm::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/importlib/metadata/__init__.py

   (2) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package

   (3) 
https://packaging.python.org/en/latest/glossary/#term-Import-Package

   (4) 
https://setuptools.readthedocs.io/en/latest/pkg_resources.html#entry-points

   (5) 
https://setuptools.readthedocs.io/en/latest/pkg_resources.html#metadata-api

   (6) https://pypi.org/project/pip/

   (7) 
https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata

   (8) https://importlib-metadata.readthedocs.io/en/latest/api.html

   (9) 
https://importlib-metadata.readthedocs.io/en/latest/migration.html


File: python.info,  Node: Overview<3>,  Next: Functional API<2>,  Up: importlib metadata – Accessing package metadata

5.31.8.1 Overview
.................

Let’s say you wanted to get the version string for a Distribution
Package(1) you’ve installed using ‘pip’.  We start by creating a virtual
environment and installing something into it:

     $ python -m venv example
     $ source example/bin/activate
     (example) $ python -m pip install wheel

You can get the version string for ‘wheel’ by running the following:

     (example) $ python
     >>> from importlib.metadata import version
     >>> version('wheel')
     '0.32.3'

You can also get a collection of entry points selectable by properties
of the EntryPoint (typically ‘group’ or ‘name’), such as
‘console_scripts’, ‘distutils.commands’ and others.  Each group contains
a collection of *note EntryPoint: 284. objects.

You can get the *note metadata for a distribution: 47ed.:

     >>> list(metadata('wheel'))
     ['Metadata-Version', 'Name', 'Version', 'Summary', 'Home-page', 'Author', 'Author-email', 'Maintainer', 'Maintainer-email', 'License', 'Project-URL', 'Project-URL', 'Project-URL', 'Keywords', 'Platform', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Classifier', 'Requires-Python', 'Provides-Extra', 'Requires-Dist', 'Requires-Dist']

You can also get a *note distribution’s version number: 47ee, list its
*note constituent files: 47ef, and get a list of the distribution’s
*note Distribution requirements: 47f0.

 -- Exception: importlib.metadata.PackageNotFoundError

     Subclass of *note ModuleNotFoundError: b61. raised by several
     functions in this module when queried for a distribution package
     which is not installed in the current Python environment.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package


File: python.info,  Node: Functional API<2>,  Next: Distributions,  Prev: Overview<3>,  Up: importlib metadata – Accessing package metadata

5.31.8.2 Functional API
.......................

This package provides the following functionality via its public API.

* Menu:

* Entry points::
* Distribution metadata::
* Distribution versions::
* Distribution files::
* Distribution requirements::
* Mapping import to distribution packages::


File: python.info,  Node: Entry points,  Next: Distribution metadata,  Up: Functional API<2>

5.31.8.3 Entry points
.....................

 -- Function: importlib.metadata.entry_points (**select_params)

     Returns a *note EntryPoints: 47f5. instance describing entry points
     for the current environment.  Any given keyword parameters are
     passed to the ‘select()’ method for comparison to the attributes of
     the individual entry point definitions.

     Note: it is not currently possible to query for entry points based
     on their ‘EntryPoint.dist’ attribute (as different ‘Distribution’
     instances do not currently compare equal, even if they have the
     same attributes)

 -- Class: importlib.metadata.EntryPoints

     Details of a collection of installed entry points.

     Also provides a ‘.groups’ attribute that reports all identified
     entry point groups, and a ‘.names’ attribute that reports all
     identified entry point names.

 -- Class: importlib.metadata.EntryPoint

     Details of an installed entry point.

     Each ‘EntryPoint’ instance has ‘.name’, ‘.group’, and ‘.value’
     attributes and a ‘.load()’ method to resolve the value.  There are
     also ‘.module’, ‘.attr’, and ‘.extras’ attributes for getting the
     components of the ‘.value’ attribute, and ‘.dist’ for obtaining
     information regarding the distribution package that provides the
     entry point.

Query all entry points:

     >>> eps = entry_points()

The ‘entry_points()’ function returns a ‘EntryPoints’ object, a
collection of all ‘EntryPoint’ objects with ‘names’ and ‘groups’
attributes for convenience:

     >>> sorted(eps.groups)
     ['console_scripts', 'distutils.commands', 'distutils.setup_keywords', 'egg_info.writers', 'setuptools.installation']

‘EntryPoints’ has a ‘select()’ method to select entry points matching
specific properties.  Select entry points in the ‘console_scripts’
group:

     >>> scripts = eps.select(group='console_scripts')

Equivalently, since ‘entry_points()’ passes keyword arguments through to
select:

     >>> scripts = entry_points(group='console_scripts')

Pick out a specific script named “wheel” (found in the wheel project):

     >>> 'wheel' in scripts.names
     True
     >>> wheel = scripts['wheel']

Equivalently, query for that entry point during selection:

     >>> (wheel,) = entry_points(group='console_scripts', name='wheel')
     >>> (wheel,) = entry_points().select(group='console_scripts', name='wheel')

Inspect the resolved entry point:

     >>> wheel
     EntryPoint(name='wheel', value='wheel.cli:main', group='console_scripts')
     >>> wheel.module
     'wheel.cli'
     >>> wheel.attr
     'main'
     >>> wheel.extras
     []
     >>> main = wheel.load()
     >>> main
     <function main at 0x103528488>

The ‘group’ and ‘name’ are arbitrary values defined by the package
author and usually a client will wish to resolve all entry points for a
particular group.  Read the setuptools docs(1) for more information on
entry points, their definition, and usage.

Changed in version 3.12: The “selectable” entry points were introduced
in ‘importlib_metadata’ 3.6 and Python 3.10.  Prior to those changes,
‘entry_points’ accepted no parameters and always returned a dictionary
of entry points, keyed by group.  With ‘importlib_metadata’ 5.0 and
Python 3.12, ‘entry_points’ always returns an ‘EntryPoints’ object.  See
backports.entry_points_selectable(2) for compatibility options.

Changed in version 3.13: ‘EntryPoint’ objects no longer present a
tuple-like interface (*note __getitem__(): 283.).

   ---------- Footnotes ----------

   (1) https://setuptools.pypa.io/en/latest/userguide/entry_point.html

   (2) https://pypi.org/project/backports.entry_points_selectable/


File: python.info,  Node: Distribution metadata,  Next: Distribution versions,  Prev: Entry points,  Up: Functional API<2>

5.31.8.4 Distribution metadata
..............................

 -- Function: importlib.metadata.metadata (distribution_name)

     Return the distribution metadata corresponding to the named
     distribution package as a *note PackageMetadata: 47f9. instance.

     Raises *note PackageNotFoundError: 47f1. if the named distribution
     package is not installed in the current Python environment.

 -- Class: importlib.metadata.PackageMetadata

     A concrete implementation of the PackageMetadata protocol(1).

     In addition to providing the defined protocol methods and
     attributes, subscripting the instance is equivalent to calling the
     ‘get()’ method.

Every Distribution Package(2) includes some metadata, which you can
extract using the ‘metadata()’ function:

     >>> wheel_metadata = metadata('wheel')

The keys of the returned data structure name the metadata keywords, and
the values are returned unparsed from the distribution metadata:

     >>> wheel_metadata['Requires-Python']
     '>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'

*note PackageMetadata: 47f9. also presents a ‘json’ attribute that
returns all the metadata in a JSON-compatible form per PEP 566(3):

     >>> wheel_metadata.json['requires_python']
     '>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'

The full set of available metadata is not described here.  See the PyPA
Core metadata specification(4) for additional details.

Changed in version 3.10: The ‘Description’ is now included in the
metadata when presented through the payload.  Line continuation
characters have been removed.

The ‘json’ attribute was added.

   ---------- Footnotes ----------

   (1) 
https://importlib-metadata.readthedocs.io/en/latest/api.html#importlib_metadata.PackageMetadata

   (2) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package

   (3) https://peps.python.org/pep-0566/

   (4) 
https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata


File: python.info,  Node: Distribution versions,  Next: Distribution files,  Prev: Distribution metadata,  Up: Functional API<2>

5.31.8.5 Distribution versions
..............................

 -- Function: importlib.metadata.version (distribution_name)

     Return the installed distribution package version(1) for the named
     distribution package.

     Raises *note PackageNotFoundError: 47f1. if the named distribution
     package is not installed in the current Python environment.

The ‘version()’ function is the quickest way to get a Distribution
Package(2)’s version number, as a string:

     >>> version('wheel')
     '0.32.3'

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/specifications/core-metadata/#version

   (2) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package


File: python.info,  Node: Distribution files,  Next: Distribution requirements,  Prev: Distribution versions,  Up: Functional API<2>

5.31.8.6 Distribution files
...........................

 -- Function: importlib.metadata.files (distribution_name)

     Return the full set of files contained within the named
     distribution package.

     Raises *note PackageNotFoundError: 47f1. if the named distribution
     package is not installed in the current Python environment.

     Returns *note None: 678. if the distribution is found but the
     installation database records reporting the files associated with
     the distribuion package are missing.

 -- Class: importlib.metadata.PackagePath

     A *note pathlib.PurePath: 4a9. derived object with additional
     ‘dist’, ‘size’, and ‘hash’ properties corresponding to the
     distribution package’s installation metadata for that file.

The ‘files()’ function takes a Distribution Package(1) name and returns
all of the files installed by this distribution.  Each file is reported
as a *note PackagePath: 47fd. instance.  For example:

     >>> util = [p for p in files('wheel') if 'util.py' in str(p)][0]
     >>> util
     PackagePath('wheel/util.py')
     >>> util.size
     859
     >>> util.dist
     <importlib.metadata._hooks.PathDistribution object at 0x101e0cef0>
     >>> util.hash
     <FileHash mode: sha256 value: bYkw5oMccfazVCoYQwKkkemoVyMAFoR34mmKBx8R1NI>

Once you have the file, you can also read its contents:

     >>> print(util.read_text())
     import base64
     import sys
     ...
     def as_bytes(s):
         if isinstance(s, text_type):
             return s.encode('utf-8')
         return s

You can also use the ‘locate()’ method to get the absolute path to the
file:

     >>> util.locate()
     PosixPath('/home/gustav/example/lib/site-packages/wheel/util.py')

In the case where the metadata file listing files (‘RECORD’ or
‘SOURCES.txt’) is missing, ‘files()’ will return *note None: 678.  The
caller may wish to wrap calls to ‘files()’ in always_iterable(2) or
otherwise guard against this condition if the target distribution is not
known to have the metadata present.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package

   (2) 
https://more-itertools.readthedocs.io/en/stable/api.html#more_itertools.always_iterable


File: python.info,  Node: Distribution requirements,  Next: Mapping import to distribution packages,  Prev: Distribution files,  Up: Functional API<2>

5.31.8.7 Distribution requirements
..................................

 -- Function: importlib.metadata.requires (distribution_name)

     Return the declared dependency specifiers for the named
     distribution package.

     Raises *note PackageNotFoundError: 47f1. if the named distribution
     package is not installed in the current Python environment.

To get the full set of requirements for a Distribution Package(1), use
the ‘requires()’ function:

     >>> requires('wheel')
     ["pytest (>=3.0.0) ; extra == 'test'", "pytest-cov ; extra == 'test'"]

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package


File: python.info,  Node: Mapping import to distribution packages,  Prev: Distribution requirements,  Up: Functional API<2>

5.31.8.8 Mapping import to distribution packages
................................................

 -- Function: importlib.metadata.packages_distributions ()

     Return a mapping from the top level module and import package names
     found via *note sys.meta_path: d53. to the names of the
     distribution packages (if any) that provide the corresponding
     files.

     To allow for namespace packages (which may have members provided by
     multiple distribution packages), each top level import name maps to
     a list of distribution names rather than mapping directly to a
     single name.

A convenience method to resolve the Distribution Package(1) name (or
names, in the case of a namespace package) that provide each importable
top-level Python module or Import Package(2):

     >>> packages_distributions()
     {'importlib_metadata': ['importlib-metadata'], 'yaml': ['PyYAML'], 'jaraco': ['jaraco.classes', 'jaraco.functools'], ...}

Some editable installs, do not supply top-level names(3), and thus this
function is not reliable with such installs.

Added in version 3.10.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package

   (2) 
https://packaging.python.org/en/latest/glossary/#term-Import-Package

   (3) https://github.com/pypa/packaging-problems/issues/609


File: python.info,  Node: Distributions,  Next: Distribution Discovery,  Prev: Functional API<2>,  Up: importlib metadata – Accessing package metadata

5.31.8.9 Distributions
......................

 -- Function: importlib.metadata.distribution (distribution_name)

     Return a *note Distribution: 4805. instance describing the named
     distribution package.

     Raises *note PackageNotFoundError: 47f1. if the named distribution
     package is not installed in the current Python environment.

 -- Class: importlib.metadata.Distribution

     Details of an installed distribution package.

     Note: different ‘Distribution’ instances do not currently compare
     equal, even if they relate to the same installed distribution and
     accordingly have the same attributes.

While the module level API described above is the most common and
convenient usage, you can get all of that information from the
‘Distribution’ class.  ‘Distribution’ is an abstract object that
represents the metadata for a Python Distribution Package(1).  You can
get the concrete ‘Distribution’ subclass instance for an installed
distribution package by calling the *note distribution(): 4804.
function:

     >>> from importlib.metadata import distribution
     >>> dist = distribution('wheel')
     >>> type(dist)
     <class 'importlib.metadata.PathDistribution'>

Thus, an alternative way to get the version number is through the
‘Distribution’ instance:

     >>> dist.version
     '0.32.3'

There are all kinds of additional metadata available on ‘Distribution’
instances:

     >>> dist.metadata['Requires-Python']
     '>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*'
     >>> dist.metadata['License']
     'MIT'

For editable packages, an ‘origin’ property may present PEP 610(2)
metadata:

     >>> dist.origin.url
     'file:///path/to/wheel-0.32.3.editable-py3-none-any.whl'

The full set of available metadata is not described here.  See the PyPA
Core metadata specification(3) for additional details.

Added in version 3.13: The ‘.origin’ property was added.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package

   (2) https://peps.python.org/pep-0610/

   (3) 
https://packaging.python.org/en/latest/specifications/core-metadata/#core-metadata


File: python.info,  Node: Distribution Discovery,  Next: Extending the search algorithm,  Prev: Distributions,  Up: importlib metadata – Accessing package metadata

5.31.8.10 Distribution Discovery
................................

By default, this package provides built-in support for discovery of
metadata for file system and zip file Distribution Package(1)s.  This
metadata finder search defaults to ‘sys.path’, but varies slightly in
how it interprets those values from how other import machinery does.  In
particular:

   - ‘importlib.metadata’ does not honor *note bytes: 1c2. objects on
     ‘sys.path’.

   - ‘importlib.metadata’ will incidentally honor *note pathlib.Path:
     229. objects on ‘sys.path’ even though such values will be ignored
     for imports.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package


File: python.info,  Node: Extending the search algorithm,  Prev: Distribution Discovery,  Up: importlib metadata – Accessing package metadata

5.31.8.11 Extending the search algorithm
........................................

Because Distribution Package(1) metadata is not available through *note
sys.path: 3b7. searches, or package loaders directly, the metadata for a
distribution is found through import system *note finders: 21a6.  To
find a distribution package’s metadata, ‘importlib.metadata’ queries the
list of *note meta path finders: 10ae. on *note sys.meta_path: d53.

By default ‘importlib.metadata’ installs a finder for distribution
packages found on the file system.  This finder doesn’t actually find
any 'distributions', but it can find their metadata.

The abstract class *note importlib.abc.MetaPathFinder: 875. defines the
interface expected of finders by Python’s import system.
‘importlib.metadata’ extends this protocol by looking for an optional
‘find_distributions’ callable on the finders from *note sys.meta_path:
d53. and presents this extended interface as the ‘DistributionFinder’
abstract base class, which defines this abstract method:

     @abc.abstractmethod
     def find_distributions(context=DistributionFinder.Context()):
         """Return an iterable of all Distribution instances capable of
         loading the metadata for packages for the indicated ``context``.
         """

The ‘DistributionFinder.Context’ object provides ‘.path’ and ‘.name’
properties indicating the path to search and name to match and may
supply other relevant context.

What this means in practice is that to support finding distribution
package metadata in locations other than the file system, subclass
‘Distribution’ and implement the abstract methods.  Then from a custom
finder, return instances of this derived ‘Distribution’ in the
‘find_distributions()’ method.

* Menu:

* Example: Example<14>.

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/glossary/#term-Distribution-Package


File: python.info,  Node: Example<14>,  Up: Extending the search algorithm

5.31.8.12 Example
.................

Consider for example a custom finder that loads Python modules from a
database:

     class DatabaseImporter(importlib.abc.MetaPathFinder):
         def __init__(self, db):
             self.db = db

         def find_spec(self, fullname, target=None) -> ModuleSpec:
             return self.db.spec_from_name(fullname)

     sys.meta_path.append(DatabaseImporter(connect_db(...)))

That importer now presumably provides importable modules from a
database, but it provides no metadata or entry points.  For this custom
importer to provide metadata, it would also need to implement
‘DistributionFinder’:

     from importlib.metadata import DistributionFinder

     class DatabaseImporter(DistributionFinder):
         ...

         def find_distributions(self, context=DistributionFinder.Context()):
             query = dict(name=context.name) if context.name else {}
             for dist_record in self.db.query_distributions(query):
                 yield DatabaseDistribution(dist_record)

In this way, ‘query_distributions’ would return records for each
distribution served by the database matching the query.  For example, if
‘requests-1.0’ is in the database, ‘find_distributions’ would yield a
‘DatabaseDistribution’ for ‘Context(name='requests')’ or
‘Context(name=None)’.

For the sake of simplicity, this example ignores ‘context.path’.  The
‘path’ attribute defaults to ‘sys.path’ and is the set of import paths
to be considered in the search.  A ‘DatabaseImporter’ could potentially
function without any concern for a search path.  Assuming the importer
does no partitioning, the “path” would be irrelevant.  In order to
illustrate the purpose of ‘path’, the example would need to illustrate a
more complex ‘DatabaseImporter’ whose behavior varied depending on
‘sys.path’/‘PYTHONPATH’.  In that case, the ‘find_distributions’ should
honor the ‘context.path’ and only yield ‘Distribution’s pertinent to
that path.

‘DatabaseDistribution’, then, would look something like:

     class DatabaseDistribution(importlib.metadata.Distribution):
         def __init__(self, record):
             self.record = record

         def read_text(self, filename):
             """
             Read a file like "METADATA" for the current distribution.
             """
             if filename == "METADATA":
                 return f"""Name: {self.record.name}
     Version: {self.record.version}
     """
             if filename == "entry_points.txt":
                 return "\n".join(
                   f"""[{ep.group}]\n{ep.name}={ep.value}"""
                   for ep in self.record.entry_points)

         def locate_file(self, path):
             raise RuntimeError("This distribution has no file system")

This basic implementation should provide metadata and entry points for
packages served by the ‘DatabaseImporter’, assuming that the ‘record’
supplies suitable ‘.name’, ‘.version’, and ‘.entry_points’ attributes.

The ‘DatabaseDistribution’ may also provide other metadata files, like
‘RECORD’ (required for ‘Distribution.files’) or override the
implementation of ‘Distribution.files’.  See the source for more
inspiration.


File: python.info,  Node: The initialization of the sys path module search path,  Prev: importlib metadata – Accessing package metadata,  Up: Importing Modules

5.31.9 The initialization of the ‘sys.path’ module search path
--------------------------------------------------------------

A module search path is initialized when Python starts.  This module
search path may be accessed at *note sys.path: 3b7.

The first entry in the module search path is the directory that contains
the input script, if there is one.  Otherwise, the first entry is the
current directory, which is the case when executing the interactive
shell, a *note -c: 5e3. command, or *note -m: 5e4. module.

The *note PYTHONPATH: 1058. environment variable is often used to add
directories to the search path.  If this environment variable is found
then the contents are added to the module search path.

     Note: *note PYTHONPATH: 1058. will affect all installed Python
     versions/environments.  Be wary of setting this in your shell
     profile or global environment variables.  The *note site: c7.
     module offers more nuanced techniques as mentioned below.

The next items added are the directories containing standard Python
modules as well as any *note extension module: 480c.s that these modules
depend on.  Extension modules are ‘.pyd’ files on Windows and ‘.so’
files on other platforms.  The directory with the platform-independent
Python modules is called ‘prefix’.  The directory with the extension
modules is called ‘exec_prefix’.

The *note PYTHONHOME: 3bf. environment variable may be used to set the
‘prefix’ and ‘exec_prefix’ locations.  Otherwise these directories are
found by using the Python executable as a starting point and then
looking for various ‘landmark’ files and directories.  Note that any
symbolic links are followed so the real Python executable location is
used as the search starting point.  The Python executable location is
called ‘home’.

Once ‘home’ is determined, the ‘prefix’ directory is found by first
looking for ‘python`majorversion'`minorversion'.zip’ (‘python311.zip’).
On Windows the zip archive is searched for in ‘home’ and on Unix the
archive is expected to be in ‘lib’.  Note that the expected zip archive
location is added to the module search path even if the archive does not
exist.  If no archive was found, Python on Windows will continue the
search for ‘prefix’ by looking for ‘Lib\os.py’.  Python on Unix will
look for ‘lib/python`majorversion'.`minorversion'/os.py’
(‘lib/python3.11/os.py’).  On Windows ‘prefix’ and ‘exec_prefix’ are the
same, however on other platforms
‘lib/python`majorversion'.`minorversion'/lib-dynload’
(‘lib/python3.11/lib-dynload’) is searched for and used as an anchor for
‘exec_prefix’.  On some platforms ‘lib’ may be ‘lib64’ or another value,
see *note sys.platlibdir: 942. and *note PYTHONPLATLIBDIR: 1aca.

Once found, ‘prefix’ and ‘exec_prefix’ are available at *note
sys.prefix: 3b9. and *note sys.exec_prefix: 3b5. respectively.

Finally, the *note site: c7. module is processed and ‘site-packages’
directories are added to the module search path.  A common way to
customize the search path is to create *note sitecustomize: c8. or *note
usercustomize: 10e. modules as described in the ‘site’ module
documentation.

     Note: Certain command line options may further affect path
     calculations.  See *note -E: 967, *note -I: 968, *note -s: 13db.
     and *note -S: 11ec. for further details.

* Menu:

* Virtual environments: Virtual environments<2>.
* _pth files::
* Embedded Python::


File: python.info,  Node: Virtual environments<2>,  Next: _pth files,  Up: The initialization of the sys path module search path

5.31.9.1 Virtual environments
.............................

If Python is run in a virtual environment (as described at *note Virtual
Environments and Packages: 1ea2.) then ‘prefix’ and ‘exec_prefix’ are
specific to the virtual environment.

If a ‘pyvenv.cfg’ file is found alongside the main executable, or in the
directory one level above the executable, the following variations
apply:

   * If ‘home’ is an absolute path and *note PYTHONHOME: 3bf. is not
     set, this path is used instead of the path to the main executable
     when deducing ‘prefix’ and ‘exec_prefix’.


File: python.info,  Node: _pth files,  Next: Embedded Python,  Prev: Virtual environments<2>,  Up: The initialization of the sys path module search path

5.31.9.2 _pth files
...................

To completely override *note sys.path: 3b7. create a ‘._pth’ file with
the same name as the shared library or executable (‘python._pth’ or
‘python311._pth’).  The shared library path is always known on Windows,
however it may not be available on other platforms.  In the ‘._pth’ file
specify one line for each path to add to ‘sys.path’.  The file based on
the shared library name overrides the one based on the executable, which
allows paths to be restricted for any program loading the runtime if
desired.

When the file exists, all registry and environment variables are
ignored, isolated mode is enabled, and *note site: c7. is not imported
unless one line in the file specifies ‘import site’.  Blank paths and
lines starting with ‘#’ are ignored.  Each path may be absolute or
relative to the location of the file.  Import statements other than to
‘site’ are not permitted, and arbitrary code cannot be specified.

Note that ‘.pth’ files (without leading underscore) will be processed
normally by the *note site: c7. module when ‘import site’ has been
specified.


File: python.info,  Node: Embedded Python,  Prev: _pth files,  Up: The initialization of the sys path module search path

5.31.9.3 Embedded Python
........................

If Python is embedded within another application *note
Py_InitializeFromConfig(): 3c8. and the *note PyConfig: 3a9. structure
can be used to initialize Python.  The path specific details are
described at *note Python Path Configuration: 8b5.

See also
........

   * *note Finding modules: c41. for detailed Windows notes.

   * *note Using Python on Unix platforms: 1efc. for Unix details.


File: python.info,  Node: Python Language Services,  Next: MS Windows Specific Services,  Prev: Importing Modules,  Up: The Python Standard Library

5.32 Python Language Services
=============================

Python provides a number of modules to assist in working with the Python
language.  These modules support tokenizing, parsing, syntax analysis,
bytecode disassembly, and various other facilities.

These modules include:

* Menu:

* ast — Abstract Syntax Trees::
* symtable — Access to the compiler’s symbol tables::
* token — Constants used with Python parse trees::
* keyword — Testing for Python keywords::
* tokenize — Tokenizer for Python source::
* tabnanny — Detection of ambiguous indentation::
* pyclbr — Python module browser support::
* py_compile — Compile Python source files::
* compileall — Byte-compile Python libraries::
* dis — Disassembler for Python bytecode::
* pickletools — Tools for pickle developers::


File: python.info,  Node: ast — Abstract Syntax Trees,  Next: symtable — Access to the compiler’s symbol tables,  Up: Python Language Services

5.32.1 ‘ast’ — Abstract Syntax Trees
------------------------------------

'Source code:' Lib/ast.py(1)

__________________________________________________________________

The ‘ast’ module helps Python applications to process trees of the
Python abstract syntax grammar.  The abstract syntax itself might change
with each Python release; this module helps to find out programmatically
what the current grammar looks like.

An abstract syntax tree can be generated by passing *note
ast.PyCF_ONLY_AST: 4816. as a flag to the *note compile(): 192. built-in
function, or using the *note parse(): 1a8. helper provided in this
module.  The result will be a tree of objects whose classes all inherit
from *note ast.AST: 1a6.  An abstract syntax tree can be compiled into a
Python code object using the built-in ‘compile()’ function.

* Menu:

* Abstract Grammar::
* Node classes::
* ast Helpers::
* Compiler Flags::
* Command-Line Usage: Command-Line Usage<4>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/ast.py


File: python.info,  Node: Abstract Grammar,  Next: Node classes,  Up: ast — Abstract Syntax Trees

5.32.1.1 Abstract Grammar
.........................

The abstract grammar is currently defined as follows:

     -- ASDL's 4 builtin types are:
     -- identifier, int, string, constant

     module Python
     {
         mod = Module(stmt* body, type_ignore* type_ignores)
             | Interactive(stmt* body)
             | Expression(expr body)
             | FunctionType(expr* argtypes, expr returns)

         stmt = FunctionDef(identifier name, arguments args,
                            stmt* body, expr* decorator_list, expr? returns,
                            string? type_comment, type_param* type_params)
               | AsyncFunctionDef(identifier name, arguments args,
                                  stmt* body, expr* decorator_list, expr? returns,
                                  string? type_comment, type_param* type_params)

               | ClassDef(identifier name,
                  expr* bases,
                  keyword* keywords,
                  stmt* body,
                  expr* decorator_list,
                  type_param* type_params)
               | Return(expr? value)

               | Delete(expr* targets)
               | Assign(expr* targets, expr value, string? type_comment)
               | TypeAlias(expr name, type_param* type_params, expr value)
               | AugAssign(expr target, operator op, expr value)
               -- 'simple' indicates that we annotate simple name without parens
               | AnnAssign(expr target, expr annotation, expr? value, int simple)

               -- use 'orelse' because else is a keyword in target languages
               | For(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
               | AsyncFor(expr target, expr iter, stmt* body, stmt* orelse, string? type_comment)
               | While(expr test, stmt* body, stmt* orelse)
               | If(expr test, stmt* body, stmt* orelse)
               | With(withitem* items, stmt* body, string? type_comment)
               | AsyncWith(withitem* items, stmt* body, string? type_comment)

               | Match(expr subject, match_case* cases)

               | Raise(expr? exc, expr? cause)
               | Try(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
               | TryStar(stmt* body, excepthandler* handlers, stmt* orelse, stmt* finalbody)
               | Assert(expr test, expr? msg)

               | Import(alias* names)
               | ImportFrom(identifier? module, alias* names, int? level)

               | Global(identifier* names)
               | Nonlocal(identifier* names)
               | Expr(expr value)
               | Pass | Break | Continue

               -- col_offset is the byte offset in the utf8 string the parser uses
               attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

               -- BoolOp() can use left & right?
         expr = BoolOp(boolop op, expr* values)
              | NamedExpr(expr target, expr value)
              | BinOp(expr left, operator op, expr right)
              | UnaryOp(unaryop op, expr operand)
              | Lambda(arguments args, expr body)
              | IfExp(expr test, expr body, expr orelse)
              | Dict(expr* keys, expr* values)
              | Set(expr* elts)
              | ListComp(expr elt, comprehension* generators)
              | SetComp(expr elt, comprehension* generators)
              | DictComp(expr key, expr value, comprehension* generators)
              | GeneratorExp(expr elt, comprehension* generators)
              -- the grammar constrains where yield expressions can occur
              | Await(expr value)
              | Yield(expr? value)
              | YieldFrom(expr value)
              -- need sequences for compare to distinguish between
              -- x < 4 < 3 and (x < 4) < 3
              | Compare(expr left, cmpop* ops, expr* comparators)
              | Call(expr func, expr* args, keyword* keywords)
              | FormattedValue(expr value, int conversion, expr? format_spec)
              | JoinedStr(expr* values)
              | Constant(constant value, string? kind)

              -- the following expression can appear in assignment context
              | Attribute(expr value, identifier attr, expr_context ctx)
              | Subscript(expr value, expr slice, expr_context ctx)
              | Starred(expr value, expr_context ctx)
              | Name(identifier id, expr_context ctx)
              | List(expr* elts, expr_context ctx)
              | Tuple(expr* elts, expr_context ctx)

              -- can appear only in Subscript
              | Slice(expr? lower, expr? upper, expr? step)

               -- col_offset is the byte offset in the utf8 string the parser uses
               attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

         expr_context = Load | Store | Del

         boolop = And | Or

         operator = Add | Sub | Mult | MatMult | Div | Mod | Pow | LShift
                      | RShift | BitOr | BitXor | BitAnd | FloorDiv

         unaryop = Invert | Not | UAdd | USub

         cmpop = Eq | NotEq | Lt | LtE | Gt | GtE | Is | IsNot | In | NotIn

         comprehension = (expr target, expr iter, expr* ifs, int is_async)

         excepthandler = ExceptHandler(expr? type, identifier? name, stmt* body)
                         attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

         arguments = (arg* posonlyargs, arg* args, arg? vararg, arg* kwonlyargs,
                      expr* kw_defaults, arg? kwarg, expr* defaults)

         arg = (identifier arg, expr? annotation, string? type_comment)
                attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

         -- keyword arguments supplied to call (NULL identifier for **kwargs)
         keyword = (identifier? arg, expr value)
                    attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

         -- import name with optional 'as' alias.
         alias = (identifier name, identifier? asname)
                  attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)

         withitem = (expr context_expr, expr? optional_vars)

         match_case = (pattern pattern, expr? guard, stmt* body)

         pattern = MatchValue(expr value)
                 | MatchSingleton(constant value)
                 | MatchSequence(pattern* patterns)
                 | MatchMapping(expr* keys, pattern* patterns, identifier? rest)
                 | MatchClass(expr cls, pattern* patterns, identifier* kwd_attrs, pattern* kwd_patterns)

                 | MatchStar(identifier? name)
                 -- The optional "rest" MatchMapping parameter handles capturing extra mapping keys

                 | MatchAs(pattern? pattern, identifier? name)
                 | MatchOr(pattern* patterns)

                  attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)

         type_ignore = TypeIgnore(int lineno, string tag)

         type_param = TypeVar(identifier name, expr? bound, expr? default_value)
                    | ParamSpec(identifier name, expr? default_value)
                    | TypeVarTuple(identifier name, expr? default_value)
                    attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)
     }


File: python.info,  Node: Node classes,  Next: ast Helpers,  Prev: Abstract Grammar,  Up: ast — Abstract Syntax Trees

5.32.1.2 Node classes
.....................

 -- Class: ast.AST

     This is the base of all AST node classes.  The actual node classes
     are derived from the ‘Parser/Python.asdl’ file, which is reproduced
     *note above: 4817.  They are defined in the ‘_ast’ C module and
     re-exported in ‘ast’.

     There is one class defined for each left-hand side symbol in the
     abstract grammar (for example, ‘ast.stmt’ or ‘ast.expr’).  In
     addition, there is one class defined for each constructor on the
     right-hand side; these classes inherit from the classes for the
     left-hand side trees.  For example, *note ast.BinOp: 1b5d. inherits
     from ‘ast.expr’.  For production rules with alternatives (aka
     “sums”), the left-hand side class is abstract: only instances of
     specific constructor nodes are ever created.

      -- Attribute: _fields

          Each concrete class has an attribute ‘_fields’ which gives the
          names of all child nodes.

          Each instance of a concrete class has one attribute for each
          child node, of the type as defined in the grammar.  For
          example, *note ast.BinOp: 1b5d. instances have an attribute
          ‘left’ of type ‘ast.expr’.

          If these attributes are marked as optional in the grammar
          (using a question mark), the value might be ‘None’.  If the
          attributes can have zero-or-more values (marked with an
          asterisk), the values are represented as Python lists.  All
          possible attributes must be present and have valid values when
          compiling an AST with *note compile(): 192.

      -- Attribute: _field_types

          The ‘_field_types’ attribute on each concrete class is a
          dictionary mapping field names (as also listed in *note
          _fields: 1606.) to their types.

               >>> ast.TypeVar._field_types
               {'name': <class 'str'>, 'bound': ast.expr | None, 'default_value': ast.expr | None}

          Added in version 3.13.

      -- Attribute: lineno
      -- Attribute: col_offset
      -- Attribute: end_lineno
      -- Attribute: end_col_offset

          Instances of ‘ast.expr’ and ‘ast.stmt’ subclasses have *note
          lineno: 481a, *note col_offset: 481b, *note end_lineno: 481c,
          and *note end_col_offset: 481d. attributes.  The ‘lineno’ and
          ‘end_lineno’ are the first and last line numbers of source
          text span (1-indexed so the first line is line 1) and the
          ‘col_offset’ and ‘end_col_offset’ are the corresponding UTF-8
          byte offsets of the first and last tokens that generated the
          node.  The UTF-8 offset is recorded because the parser uses
          UTF-8 internally.

          Note that the end positions are not required by the compiler
          and are therefore optional.  The end offset is 'after' the
          last symbol, for example one can get the source segment of a
          one-line expression node using ‘source_line[node.col_offset :
          node.end_col_offset]’.

     The constructor of a class ‘ast.T’ parses its arguments as follows:

        * If there are positional arguments, there must be as many as
          there are items in ‘T._fields’; they will be assigned as
          attributes of these names.

        * If there are keyword arguments, they will set the attributes
          of the same names to the given values.

     For example, to create and populate an *note ast.UnaryOp: 481e.
     node, you could use

          node = ast.UnaryOp(ast.USub(), ast.Constant(5, lineno=0, col_offset=0),
                             lineno=0, col_offset=0)

     If a field that is optional in the grammar is omitted from the
     constructor, it defaults to ‘None’.  If a list field is omitted, it
     defaults to the empty list.  If a field of type ‘ast.expr_context’
     is omitted, it defaults to *note Load(): 1a4.  If any other field
     is omitted, a *note DeprecationWarning: 1a5. is raised and the AST
     node will not have this field.  In Python 3.15, this condition will
     raise an error.

Changed in version 3.8: Class *note ast.Constant: 2b9. is now used for
all constants.

Changed in version 3.9: Simple indices are represented by their value,
extended slices are represented as tuples.

Changed in version 3.13: AST node constructors were changed to provide
sensible defaults for omitted fields: optional fields now default to
‘None’, list fields default to an empty list, and fields of type
‘ast.expr_context’ default to *note Load(): 1a4.  Previously, omitted
attributes would not exist on constructed nodes (accessing them raised
*note AttributeError: 34e.).

Deprecated since version 3.8: Old classes ‘ast.Num’, ‘ast.Str’,
‘ast.Bytes’, ‘ast.NameConstant’ and ‘ast.Ellipsis’ are still available,
but they will be removed in future Python releases.  In the meantime,
instantiating them will return an instance of a different class.

Deprecated since version 3.9: Old classes ‘ast.Index’ and ‘ast.ExtSlice’
are still available, but they will be removed in future Python releases.
In the meantime, instantiating them will return an instance of a
different class.

Deprecated since version 3.13, will be removed in version 3.15: Previous
versions of Python allowed the creation of AST nodes that were missing
required fields.  Similarly, AST node constructors allowed arbitrary
keyword arguments that were set as attributes of the AST node, even if
they did not match any of the fields of the AST node.  This behavior is
deprecated and will be removed in Python 3.15.

     Note: The descriptions of the specific node classes displayed here
     were initially adapted from the fantastic Green Tree Snakes(1)
     project and all its contributors.

* Menu:

* Root nodes::
* Literals: Literals<3>.
* Variables::
* Expressions: Expressions<2>.
* Statements::
* Control flow::
* Pattern matching::
* Type annotations::
* Type parameters::
* Function and class definitions::
* Async and await::

   ---------- Footnotes ----------

   (1) https://greentreesnakes.readthedocs.io/en/latest/


File: python.info,  Node: Root nodes,  Next: Literals<3>,  Up: Node classes

5.32.1.3 Root nodes
...................

 -- Class: ast.Module (body, type_ignores)

     A Python module, as with *note file input: 22f6.  Node type
     generated by *note ast.parse(): 1a8. in the default ‘"exec"’
     'mode'.

     ‘body’ is a *note list: 614. of the module’s *note Statements:
     4822.

     ‘type_ignores’ is a *note list: 614. of the module’s type ignore
     comments; see *note ast.parse(): 1a8. for more details.

          >>> print(ast.dump(ast.parse('x = 1'), indent=4))
          Module(
              body=[
                  Assign(
                      targets=[
                          Name(id='x', ctx=Store())],
                      value=Constant(value=1))])

 -- Class: ast.Expression (body)

     A single Python *note expression input: 22fc.  Node type generated
     by *note ast.parse(): 1a8. when 'mode' is ‘"eval"’.

     ‘body’ is a single node, one of the *note expression types: 4824.

          >>> print(ast.dump(ast.parse('123', mode='eval'), indent=4))
          Expression(
              body=Constant(value=123))

 -- Class: ast.Interactive (body)

     A single *note interactive input: 22f9, like in *note Interactive
     Mode: 16f.  Node type generated by *note ast.parse(): 1a8. when
     'mode' is ‘"single"’.

     ‘body’ is a *note list: 614. of *note statement nodes: 4822.

          >>> print(ast.dump(ast.parse('x = 1; y = 2', mode='single'), indent=4))
          Interactive(
              body=[
                  Assign(
                      targets=[
                          Name(id='x', ctx=Store())],
                      value=Constant(value=1)),
                  Assign(
                      targets=[
                          Name(id='y', ctx=Store())],
                      value=Constant(value=2))])

 -- Class: ast.FunctionType (argtypes, returns)

     A representation of an old-style type comments for functions, as
     Python versions prior to 3.5 didn’t support PEP 484(1) annotations.
     Node type generated by *note ast.parse(): 1a8. when 'mode' is
     ‘"func_type"’.

     Such type comments would look like this:

          def sum_two_number(a, b):
              # type: (int, int) -> int
              return a + b

     ‘argtypes’ is a *note list: 614. of *note expression nodes: 4824.

     ‘returns’ is a single *note expression node: 4824.

          >>> print(ast.dump(ast.parse('(int, str) -> List[int]', mode='func_type'), indent=4))
          FunctionType(
              argtypes=[
                  Name(id='int', ctx=Load()),
                  Name(id='str', ctx=Load())],
              returns=Subscript(
                  value=Name(id='List', ctx=Load()),
                  slice=Name(id='int', ctx=Load()),
                  ctx=Load()))

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/


File: python.info,  Node: Literals<3>,  Next: Variables,  Prev: Root nodes,  Up: Node classes

5.32.1.4 Literals
.................

 -- Class: ast.Constant (value)

     A constant value.  The ‘value’ attribute of the ‘Constant’ literal
     contains the Python object it represents.  The values represented
     can be instances of *note str: 44f, *note bytes: 1c2, *note int:
     257, *note float: 2f7, *note complex: 2f8, and *note bool: 46b, and
     the constants *note None: 678. and *note Ellipsis: 233f.

          >>> print(ast.dump(ast.parse('123', mode='eval'), indent=4))
          Expression(
              body=Constant(value=123))

 -- Class: ast.FormattedValue (value, conversion, format_spec)

     Node representing a single formatting field in an f-string.  If the
     string contains a single formatting field and nothing else the node
     can be isolated otherwise it appears in *note JoinedStr: 17fb.

        * ‘value’ is any expression node (such as a literal, a variable,
          or a function call).

        * ‘conversion’ is an integer:

             * -1: no formatting

             * 115: ‘!s’ string formatting

             * 114: ‘!r’ repr formatting

             * 97: ‘!a’ ascii formatting

        * ‘format_spec’ is a *note JoinedStr: 17fb. node representing
          the formatting of the value, or ‘None’ if no format was
          specified.  Both ‘conversion’ and ‘format_spec’ can be set at
          the same time.

 -- Class: ast.JoinedStr (values)

     An f-string, comprising a series of *note FormattedValue: 4828. and
     *note Constant: 2b9. nodes.

          >>> print(ast.dump(ast.parse('f"sin({a}) is {sin(a):.3}"', mode='eval'), indent=4))
          Expression(
              body=JoinedStr(
                  values=[
                      Constant(value='sin('),
                      FormattedValue(
                          value=Name(id='a', ctx=Load()),
                          conversion=-1),
                      Constant(value=') is '),
                      FormattedValue(
                          value=Call(
                              func=Name(id='sin', ctx=Load()),
                              args=[
                                  Name(id='a', ctx=Load())]),
                          conversion=-1,
                          format_spec=JoinedStr(
                              values=[
                                  Constant(value='.3')]))]))

 -- Class: ast.List (elts, ctx)
 -- Class: ast.Tuple (elts, ctx)

     A list or tuple.  ‘elts’ holds a list of nodes representing the
     elements.  ‘ctx’ is *note Store: 482b. if the container is an
     assignment target (i.e.  ‘(x,y)=something’), and *note Load: 1a4.
     otherwise.

          >>> print(ast.dump(ast.parse('[1, 2, 3]', mode='eval'), indent=4))
          Expression(
              body=List(
                  elts=[
                      Constant(value=1),
                      Constant(value=2),
                      Constant(value=3)],
                  ctx=Load()))
          >>> print(ast.dump(ast.parse('(1, 2, 3)', mode='eval'), indent=4))
          Expression(
              body=Tuple(
                  elts=[
                      Constant(value=1),
                      Constant(value=2),
                      Constant(value=3)],
                  ctx=Load()))

 -- Class: ast.Set (elts)

     A set.  ‘elts’ holds a list of nodes representing the set’s
     elements.

          >>> print(ast.dump(ast.parse('{1, 2, 3}', mode='eval'), indent=4))
          Expression(
              body=Set(
                  elts=[
                      Constant(value=1),
                      Constant(value=2),
                      Constant(value=3)]))

 -- Class: ast.Dict (keys, values)

     A dictionary.  ‘keys’ and ‘values’ hold lists of nodes representing
     the keys and the values respectively, in matching order (what would
     be returned when calling ‘dictionary.keys()’ and
     ‘dictionary.values()’).

     When doing dictionary unpacking using dictionary literals the
     expression to be expanded goes in the ‘values’ list, with a ‘None’
     at the corresponding position in ‘keys’.

          >>> print(ast.dump(ast.parse('{"a":1, **d}', mode='eval'), indent=4))
          Expression(
              body=Dict(
                  keys=[
                      Constant(value='a'),
                      None],
                  values=[
                      Constant(value=1),
                      Name(id='d', ctx=Load())]))


File: python.info,  Node: Variables,  Next: Expressions<2>,  Prev: Literals<3>,  Up: Node classes

5.32.1.5 Variables
..................

 -- Class: ast.Name (id, ctx)

     A variable name.  ‘id’ holds the name as a string, and ‘ctx’ is one
     of the following types.

 -- Class: ast.Load
 -- Class: ast.Store
 -- Class: ast.Del

     Variable references can be used to load the value of a variable, to
     assign a new value to it, or to delete it.  Variable references are
     given a context to distinguish these cases.

          >>> print(ast.dump(ast.parse('a'), indent=4))
          Module(
              body=[
                  Expr(
                      value=Name(id='a', ctx=Load()))])

          >>> print(ast.dump(ast.parse('a = 1'), indent=4))
          Module(
              body=[
                  Assign(
                      targets=[
                          Name(id='a', ctx=Store())],
                      value=Constant(value=1))])

          >>> print(ast.dump(ast.parse('del a'), indent=4))
          Module(
              body=[
                  Delete(
                      targets=[
                          Name(id='a', ctx=Del())])])

 -- Class: ast.Starred (value, ctx)

     A ‘*var’ variable reference.  ‘value’ holds the variable, typically
     a *note Name: 1ac9. node.  This type must be used when building a
     *note Call: 4830. node with ‘*args’.

          >>> print(ast.dump(ast.parse('a, *b = it'), indent=4))
          Module(
              body=[
                  Assign(
                      targets=[
                          Tuple(
                              elts=[
                                  Name(id='a', ctx=Store()),
                                  Starred(
                                      value=Name(id='b', ctx=Store()),
                                      ctx=Store())],
                              ctx=Store())],
                      value=Name(id='it', ctx=Load()))])


File: python.info,  Node: Expressions<2>,  Next: Statements,  Prev: Variables,  Up: Node classes

5.32.1.6 Expressions
....................

 -- Class: ast.Expr (value)

     When an expression, such as a function call, appears as a statement
     by itself with its return value not used or stored, it is wrapped
     in this container.  ‘value’ holds one of the other nodes in this
     section, a *note Constant: 2b9, a *note Name: 1ac9, a *note Lambda:
     4833, a *note Yield: 4834. or *note YieldFrom: 4835. node.

          >>> print(ast.dump(ast.parse('-a'), indent=4))
          Module(
              body=[
                  Expr(
                      value=UnaryOp(
                          op=USub(),
                          operand=Name(id='a', ctx=Load())))])

 -- Class: ast.UnaryOp (op, operand)

     A unary operation.  ‘op’ is the operator, and ‘operand’ any
     expression node.

 -- Class: ast.UAdd
 -- Class: ast.USub
 -- Class: ast.Not
 -- Class: ast.Invert

     Unary operator tokens.  ‘Not’ is the ‘not’ keyword, ‘Invert’ is the
     ‘~’ operator.

          >>> print(ast.dump(ast.parse('not x', mode='eval'), indent=4))
          Expression(
              body=UnaryOp(
                  op=Not(),
                  operand=Name(id='x', ctx=Load())))

 -- Class: ast.BinOp (left, op, right)

     A binary operation (like addition or division).  ‘op’ is the
     operator, and ‘left’ and ‘right’ are any expression nodes.

          >>> print(ast.dump(ast.parse('x + y', mode='eval'), indent=4))
          Expression(
              body=BinOp(
                  left=Name(id='x', ctx=Load()),
                  op=Add(),
                  right=Name(id='y', ctx=Load())))

 -- Class: ast.Add
 -- Class: ast.Sub
 -- Class: ast.Mult
 -- Class: ast.Div
 -- Class: ast.FloorDiv
 -- Class: ast.Mod
 -- Class: ast.Pow
 -- Class: ast.LShift
 -- Class: ast.RShift
 -- Class: ast.BitOr
 -- Class: ast.BitXor
 -- Class: ast.BitAnd
 -- Class: ast.MatMult

     Binary operator tokens.

 -- Class: ast.BoolOp (op, values)

     A boolean operation, ‘or’ or ‘and’.  ‘op’ is *note Or: 4848. or
     *note And: 4849.  ‘values’ are the values involved.  Consecutive
     operations with the same operator, such as ‘a or b or c’, are
     collapsed into one node with several values.

     This doesn’t include ‘not’, which is a *note UnaryOp: 481e.

          >>> print(ast.dump(ast.parse('x or y', mode='eval'), indent=4))
          Expression(
              body=BoolOp(
                  op=Or(),
                  values=[
                      Name(id='x', ctx=Load()),
                      Name(id='y', ctx=Load())]))

 -- Class: ast.And
 -- Class: ast.Or

     Boolean operator tokens.

 -- Class: ast.Compare (left, ops, comparators)

     A comparison of two or more values.  ‘left’ is the first value in
     the comparison, ‘ops’ the list of operators, and ‘comparators’ the
     list of values after the first element in the comparison.

          >>> print(ast.dump(ast.parse('1 <= a < 10', mode='eval'), indent=4))
          Expression(
              body=Compare(
                  left=Constant(value=1),
                  ops=[
                      LtE(),
                      Lt()],
                  comparators=[
                      Name(id='a', ctx=Load()),
                      Constant(value=10)]))

 -- Class: ast.Eq
 -- Class: ast.NotEq
 -- Class: ast.Lt
 -- Class: ast.LtE
 -- Class: ast.Gt
 -- Class: ast.GtE
 -- Class: ast.Is
 -- Class: ast.IsNot
 -- Class: ast.In
 -- Class: ast.NotIn

     Comparison operator tokens.

 -- Class: ast.Call (func, args, keywords)

     A function call.  ‘func’ is the function, which will often be a
     *note Name: 1ac9. or *note Attribute: 4855. object.  Of the
     arguments:

        * ‘args’ holds a list of the arguments passed by position.

        * ‘keywords’ holds a list of *note keyword: 4856. objects
          representing arguments passed by keyword.

     The ‘args’ and ‘keywords’ arguments are optional and default to
     empty lists.

          >>> print(ast.dump(ast.parse('func(a, b=c, *d, **e)', mode='eval'), indent=4))
          Expression(
              body=Call(
                  func=Name(id='func', ctx=Load()),
                  args=[
                      Name(id='a', ctx=Load()),
                      Starred(
                          value=Name(id='d', ctx=Load()),
                          ctx=Load())],
                  keywords=[
                      keyword(
                          arg='b',
                          value=Name(id='c', ctx=Load())),
                      keyword(
                          value=Name(id='e', ctx=Load()))]))

 -- Class: ast.keyword (arg, value)

     A keyword argument to a function call or class definition.  ‘arg’
     is a raw string of the parameter name, ‘value’ is a node to pass
     in.

 -- Class: ast.IfExp (test, body, orelse)

     An expression such as ‘a if b else c’.  Each field holds a single
     node, so in the following example, all three are *note Name: 1ac9.
     nodes.

          >>> print(ast.dump(ast.parse('a if b else c', mode='eval'), indent=4))
          Expression(
              body=IfExp(
                  test=Name(id='b', ctx=Load()),
                  body=Name(id='a', ctx=Load()),
                  orelse=Name(id='c', ctx=Load())))

 -- Class: ast.Attribute (value, attr, ctx)

     Attribute access, e.g.  ‘d.keys’.  ‘value’ is a node, typically a
     *note Name: 1ac9.  ‘attr’ is a bare string giving the name of the
     attribute, and ‘ctx’ is *note Load: 1a4, *note Store: 482b. or
     *note Del: 482e. according to how the attribute is acted on.

          >>> print(ast.dump(ast.parse('snake.colour', mode='eval'), indent=4))
          Expression(
              body=Attribute(
                  value=Name(id='snake', ctx=Load()),
                  attr='colour',
                  ctx=Load()))

 -- Class: ast.NamedExpr (target, value)

     A named expression.  This AST node is produced by the assignment
     expressions operator (also known as the walrus operator).  As
     opposed to the *note Assign: 4859. node in which the first argument
     can be multiple nodes, in this case both ‘target’ and ‘value’ must
     be single nodes.

          >>> print(ast.dump(ast.parse('(x := 4)', mode='eval'), indent=4))
          Expression(
              body=NamedExpr(
                  target=Name(id='x', ctx=Store()),
                  value=Constant(value=4)))

     Added in version 3.8.

* Menu:

* Subscripting::
* Comprehensions::


File: python.info,  Node: Subscripting,  Next: Comprehensions,  Up: Expressions<2>

5.32.1.7 Subscripting
.....................

 -- Class: ast.Subscript (value, slice, ctx)

     A subscript, such as ‘l[1]’.  ‘value’ is the subscripted object
     (usually sequence or mapping).  ‘slice’ is an index, slice or key.
     It can be a *note Tuple: 482a. and contain a *note Slice: 485c.
     ‘ctx’ is *note Load: 1a4, *note Store: 482b. or *note Del: 482e.
     according to the action performed with the subscript.

          >>> print(ast.dump(ast.parse('l[1:2, 3]', mode='eval'), indent=4))
          Expression(
              body=Subscript(
                  value=Name(id='l', ctx=Load()),
                  slice=Tuple(
                      elts=[
                          Slice(
                              lower=Constant(value=1),
                              upper=Constant(value=2)),
                          Constant(value=3)],
                      ctx=Load()),
                  ctx=Load()))

 -- Class: ast.Slice (lower, upper, step)

     Regular slicing (on the form ‘lower:upper’ or ‘lower:upper:step’).
     Can occur only inside the 'slice' field of *note Subscript: 485b,
     either directly or as an element of *note Tuple: 482a.

          >>> print(ast.dump(ast.parse('l[1:2]', mode='eval'), indent=4))
          Expression(
              body=Subscript(
                  value=Name(id='l', ctx=Load()),
                  slice=Slice(
                      lower=Constant(value=1),
                      upper=Constant(value=2)),
                  ctx=Load()))


File: python.info,  Node: Comprehensions,  Prev: Subscripting,  Up: Expressions<2>

5.32.1.8 Comprehensions
.......................

 -- Class: ast.ListComp (elt, generators)
 -- Class: ast.SetComp (elt, generators)
 -- Class: ast.GeneratorExp (elt, generators)
 -- Class: ast.DictComp (key, value, generators)

     List and set comprehensions, generator expressions, and dictionary
     comprehensions.  ‘elt’ (or ‘key’ and ‘value’) is a single node
     representing the part that will be evaluated for each item.

     ‘generators’ is a list of *note comprehension: 4862. nodes.

          >>> print(ast.dump(
          ...     ast.parse('[x for x in numbers]', mode='eval'),
          ...     indent=4,
          ... ))
          Expression(
              body=ListComp(
                  elt=Name(id='x', ctx=Load()),
                  generators=[
                      comprehension(
                          target=Name(id='x', ctx=Store()),
                          iter=Name(id='numbers', ctx=Load()),
                          is_async=0)]))
          >>> print(ast.dump(
          ...     ast.parse('{x: x**2 for x in numbers}', mode='eval'),
          ...     indent=4,
          ... ))
          Expression(
              body=DictComp(
                  key=Name(id='x', ctx=Load()),
                  value=BinOp(
                      left=Name(id='x', ctx=Load()),
                      op=Pow(),
                      right=Constant(value=2)),
                  generators=[
                      comprehension(
                          target=Name(id='x', ctx=Store()),
                          iter=Name(id='numbers', ctx=Load()),
                          is_async=0)]))
          >>> print(ast.dump(
          ...     ast.parse('{x for x in numbers}', mode='eval'),
          ...     indent=4,
          ... ))
          Expression(
              body=SetComp(
                  elt=Name(id='x', ctx=Load()),
                  generators=[
                      comprehension(
                          target=Name(id='x', ctx=Store()),
                          iter=Name(id='numbers', ctx=Load()),
                          is_async=0)]))

 -- Class: ast.comprehension (target, iter, ifs, is_async)

     One ‘for’ clause in a comprehension.  ‘target’ is the reference to
     use for each element - typically a *note Name: 1ac9. or *note
     Tuple: 482a. node.  ‘iter’ is the object to iterate over.  ‘ifs’ is
     a list of test expressions: each ‘for’ clause can have multiple
     ‘ifs’.

     ‘is_async’ indicates a comprehension is asynchronous (using an
     ‘async for’ instead of ‘for’).  The value is an integer (0 or 1).

          >>> print(ast.dump(ast.parse('[ord(c) for line in file for c in line]', mode='eval'),
          ...                indent=4)) # Multiple comprehensions in one.
          Expression(
              body=ListComp(
                  elt=Call(
                      func=Name(id='ord', ctx=Load()),
                      args=[
                          Name(id='c', ctx=Load())]),
                  generators=[
                      comprehension(
                          target=Name(id='line', ctx=Store()),
                          iter=Name(id='file', ctx=Load()),
                          is_async=0),
                      comprehension(
                          target=Name(id='c', ctx=Store()),
                          iter=Name(id='line', ctx=Load()),
                          is_async=0)]))

          >>> print(ast.dump(ast.parse('(n**2 for n in it if n>5 if n<10)', mode='eval'),
          ...                indent=4)) # generator comprehension
          Expression(
              body=GeneratorExp(
                  elt=BinOp(
                      left=Name(id='n', ctx=Load()),
                      op=Pow(),
                      right=Constant(value=2)),
                  generators=[
                      comprehension(
                          target=Name(id='n', ctx=Store()),
                          iter=Name(id='it', ctx=Load()),
                          ifs=[
                              Compare(
                                  left=Name(id='n', ctx=Load()),
                                  ops=[
                                      Gt()],
                                  comparators=[
                                      Constant(value=5)]),
                              Compare(
                                  left=Name(id='n', ctx=Load()),
                                  ops=[
                                      Lt()],
                                  comparators=[
                                      Constant(value=10)])],
                          is_async=0)]))

          >>> print(ast.dump(ast.parse('[i async for i in soc]', mode='eval'),
          ...                indent=4)) # Async comprehension
          Expression(
              body=ListComp(
                  elt=Name(id='i', ctx=Load()),
                  generators=[
                      comprehension(
                          target=Name(id='i', ctx=Store()),
                          iter=Name(id='soc', ctx=Load()),
                          is_async=1)]))


File: python.info,  Node: Statements,  Next: Control flow,  Prev: Expressions<2>,  Up: Node classes

5.32.1.9 Statements
...................

 -- Class: ast.Assign (targets, value, type_comment)

     An assignment.  ‘targets’ is a list of nodes, and ‘value’ is a
     single node.

     Multiple nodes in ‘targets’ represents assigning the same value to
     each.  Unpacking is represented by putting a *note Tuple: 482a. or
     *note List: 4829. within ‘targets’.

      -- Attribute: type_comment

          ‘type_comment’ is an optional string with the type annotation
          as a comment.

          >>> print(ast.dump(ast.parse('a = b = 1'), indent=4)) # Multiple assignment
          Module(
              body=[
                  Assign(
                      targets=[
                          Name(id='a', ctx=Store()),
                          Name(id='b', ctx=Store())],
                      value=Constant(value=1))])

          >>> print(ast.dump(ast.parse('a,b = c'), indent=4)) # Unpacking
          Module(
              body=[
                  Assign(
                      targets=[
                          Tuple(
                              elts=[
                                  Name(id='a', ctx=Store()),
                                  Name(id='b', ctx=Store())],
                              ctx=Store())],
                      value=Name(id='c', ctx=Load()))])

 -- Class: ast.AnnAssign (target, annotation, value, simple)

     An assignment with a type annotation.  ‘target’ is a single node
     and can be a *note Name: 1ac9, an *note Attribute: 4855. or a *note
     Subscript: 485b.  ‘annotation’ is the annotation, such as a *note
     Constant: 2b9. or ‘Name’ node.  ‘value’ is a single optional node.

     ‘simple’ is always either 0 (indicating a “complex” target) or 1
     (indicating a “simple” target).  A “simple” target consists solely
     of a *note Name: 1ac9. node that does not appear between
     parentheses; all other targets are considered complex.  Only simple
     targets appear in the ‘__annotations__’ dictionary of modules and
     classes.

          >>> print(ast.dump(ast.parse('c: int'), indent=4))
          Module(
              body=[
                  AnnAssign(
                      target=Name(id='c', ctx=Store()),
                      annotation=Name(id='int', ctx=Load()),
                      simple=1)])

          >>> print(ast.dump(ast.parse('(a): int = 1'), indent=4)) # Annotation with parenthesis
          Module(
              body=[
                  AnnAssign(
                      target=Name(id='a', ctx=Store()),
                      annotation=Name(id='int', ctx=Load()),
                      value=Constant(value=1),
                      simple=0)])

          >>> print(ast.dump(ast.parse('a.b: int'), indent=4)) # Attribute annotation
          Module(
              body=[
                  AnnAssign(
                      target=Attribute(
                          value=Name(id='a', ctx=Load()),
                          attr='b',
                          ctx=Store()),
                      annotation=Name(id='int', ctx=Load()),
                      simple=0)])

          >>> print(ast.dump(ast.parse('a[1]: int'), indent=4)) # Subscript annotation
          Module(
              body=[
                  AnnAssign(
                      target=Subscript(
                          value=Name(id='a', ctx=Load()),
                          slice=Constant(value=1),
                          ctx=Store()),
                      annotation=Name(id='int', ctx=Load()),
                      simple=0)])

 -- Class: ast.AugAssign (target, op, value)

     Augmented assignment, such as ‘a += 1’.  In the following example,
     ‘target’ is a *note Name: 1ac9. node for ‘x’ (with the *note Store:
     482b. context), ‘op’ is *note Add: 483a, and ‘value’ is a *note
     Constant: 2b9. with value for 1.

     The ‘target’ attribute cannot be of class *note Tuple: 482a. or
     *note List: 4829, unlike the targets of *note Assign: 4859.

          >>> print(ast.dump(ast.parse('x += 2'), indent=4))
          Module(
              body=[
                  AugAssign(
                      target=Name(id='x', ctx=Store()),
                      op=Add(),
                      value=Constant(value=2))])

 -- Class: ast.Raise (exc, cause)

     A ‘raise’ statement.  ‘exc’ is the exception object to be raised,
     normally a *note Call: 4830. or *note Name: 1ac9, or ‘None’ for a
     standalone ‘raise’.  ‘cause’ is the optional part for ‘y’ in ‘raise
     x from y’.

          >>> print(ast.dump(ast.parse('raise x from y'), indent=4))
          Module(
              body=[
                  Raise(
                      exc=Name(id='x', ctx=Load()),
                      cause=Name(id='y', ctx=Load()))])

 -- Class: ast.Assert (test, msg)

     An assertion.  ‘test’ holds the condition, such as a *note Compare:
     484a. node.  ‘msg’ holds the failure message.

          >>> print(ast.dump(ast.parse('assert x,y'), indent=4))
          Module(
              body=[
                  Assert(
                      test=Name(id='x', ctx=Load()),
                      msg=Name(id='y', ctx=Load()))])

 -- Class: ast.Delete (targets)

     Represents a ‘del’ statement.  ‘targets’ is a list of nodes, such
     as *note Name: 1ac9, *note Attribute: 4855. or *note Subscript:
     485b. nodes.

          >>> print(ast.dump(ast.parse('del x,y,z'), indent=4))
          Module(
              body=[
                  Delete(
                      targets=[
                          Name(id='x', ctx=Del()),
                          Name(id='y', ctx=Del()),
                          Name(id='z', ctx=Del())])])

 -- Class: ast.Pass

     A ‘pass’ statement.

          >>> print(ast.dump(ast.parse('pass'), indent=4))
          Module(
              body=[
                  Pass()])

 -- Class: ast.TypeAlias (name, type_params, value)

     A *note type alias: 457. created through the *note type: 43b.
     statement.  ‘name’ is the name of the alias, ‘type_params’ is a
     list of *note type parameters: 486b, and ‘value’ is the value of
     the type alias.

          >>> print(ast.dump(ast.parse('type Alias = int'), indent=4))
          Module(
              body=[
                  TypeAlias(
                      name=Name(id='Alias', ctx=Store()),
                      value=Name(id='int', ctx=Load()))])

     Added in version 3.12.

Other statements which are only applicable inside functions or loops are
described in other sections.

* Menu:

* Imports::


File: python.info,  Node: Imports,  Up: Statements

5.32.1.10 Imports
.................

 -- Class: ast.Import (names)

     An import statement.  ‘names’ is a list of *note alias: 1a1b.
     nodes.

          >>> print(ast.dump(ast.parse('import x,y,z'), indent=4))
          Module(
              body=[
                  Import(
                      names=[
                          alias(name='x'),
                          alias(name='y'),
                          alias(name='z')])])

 -- Class: ast.ImportFrom (module, names, level)

     Represents ‘from x import y’.  ‘module’ is a raw string of the
     ‘from’ name, without any leading dots, or ‘None’ for statements
     such as ‘from . import foo’.  ‘level’ is an integer holding the
     level of the relative import (0 means absolute import).

          >>> print(ast.dump(ast.parse('from y import x,y,z'), indent=4))
          Module(
              body=[
                  ImportFrom(
                      module='y',
                      names=[
                          alias(name='x'),
                          alias(name='y'),
                          alias(name='z')],
                      level=0)])

 -- Class: ast.alias (name, asname)

     Both parameters are raw strings of the names.  ‘asname’ can be
     ‘None’ if the regular name is to be used.

          >>> print(ast.dump(ast.parse('from ..foo.bar import a as b, c'), indent=4))
          Module(
              body=[
                  ImportFrom(
                      module='foo.bar',
                      names=[
                          alias(name='a', asname='b'),
                          alias(name='c')],
                      level=2)])


File: python.info,  Node: Control flow,  Next: Pattern matching,  Prev: Statements,  Up: Node classes

5.32.1.11 Control flow
......................

     Note: Optional clauses such as ‘else’ are stored as an empty list
     if they’re not present.

 -- Class: ast.If (test, body, orelse)

     An ‘if’ statement.  ‘test’ holds a single node, such as a *note
     Compare: 484a. node.  ‘body’ and ‘orelse’ each hold a list of
     nodes.

     ‘elif’ clauses don’t have a special representation in the AST, but
     rather appear as extra ‘If’ nodes within the ‘orelse’ section of
     the previous one.

          >>> print(ast.dump(ast.parse("""
          ... if x:
          ...    ...
          ... elif y:
          ...    ...
          ... else:
          ...    ...
          ... """), indent=4))
          Module(
              body=[
                  If(
                      test=Name(id='x', ctx=Load()),
                      body=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      orelse=[
                          If(
                              test=Name(id='y', ctx=Load()),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))],
                              orelse=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

 -- Class: ast.For (target, iter, body, orelse, type_comment)

     A ‘for’ loop.  ‘target’ holds the variable(s) the loop assigns to,
     as a single *note Name: 1ac9, *note Tuple: 482a, *note List: 4829,
     *note Attribute: 4855. or *note Subscript: 485b. node.  ‘iter’
     holds the item to be looped over, again as a single node.  ‘body’
     and ‘orelse’ contain lists of nodes to execute.  Those in ‘orelse’
     are executed if the loop finishes normally, rather than via a
     ‘break’ statement.

      -- Attribute: type_comment

          ‘type_comment’ is an optional string with the type annotation
          as a comment.

          >>> print(ast.dump(ast.parse("""
          ... for x in y:
          ...     ...
          ... else:
          ...     ...
          ... """), indent=4))
          Module(
              body=[
                  For(
                      target=Name(id='x', ctx=Store()),
                      iter=Name(id='y', ctx=Load()),
                      body=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      orelse=[
                          Expr(
                              value=Constant(value=Ellipsis))])])

 -- Class: ast.While (test, body, orelse)

     A ‘while’ loop.  ‘test’ holds the condition, such as a *note
     Compare: 484a. node.

          >>> print(ast.dump(ast.parse("""
          ... while x:
          ...    ...
          ... else:
          ...    ...
          ... """), indent=4))
          Module(
              body=[
                  While(
                      test=Name(id='x', ctx=Load()),
                      body=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      orelse=[
                          Expr(
                              value=Constant(value=Ellipsis))])])

 -- Class: ast.Break
 -- Class: ast.Continue

     The ‘break’ and ‘continue’ statements.

          >>> print(ast.dump(ast.parse("""\
          ... for a in b:
          ...     if a > 5:
          ...         break
          ...     else:
          ...         continue
          ...
          ... """), indent=4))
          Module(
              body=[
                  For(
                      target=Name(id='a', ctx=Store()),
                      iter=Name(id='b', ctx=Load()),
                      body=[
                          If(
                              test=Compare(
                                  left=Name(id='a', ctx=Load()),
                                  ops=[
                                      Gt()],
                                  comparators=[
                                      Constant(value=5)]),
                              body=[
                                  Break()],
                              orelse=[
                                  Continue()])])])

 -- Class: ast.Try (body, handlers, orelse, finalbody)

     ‘try’ blocks.  All attributes are list of nodes to execute, except
     for ‘handlers’, which is a list of *note ExceptHandler: 4877.
     nodes.

          >>> print(ast.dump(ast.parse("""
          ... try:
          ...    ...
          ... except Exception:
          ...    ...
          ... except OtherException as e:
          ...    ...
          ... else:
          ...    ...
          ... finally:
          ...    ...
          ... """), indent=4))
          Module(
              body=[
                  Try(
                      body=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      handlers=[
                          ExceptHandler(
                              type=Name(id='Exception', ctx=Load()),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          ExceptHandler(
                              type=Name(id='OtherException', ctx=Load()),
                              name='e',
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])],
                      orelse=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      finalbody=[
                          Expr(
                              value=Constant(value=Ellipsis))])])

 -- Class: ast.TryStar (body, handlers, orelse, finalbody)

     ‘try’ blocks which are followed by ‘except*’ clauses.  The
     attributes are the same as for *note Try: 4876. but the *note
     ExceptHandler: 4877. nodes in ‘handlers’ are interpreted as
     ‘except*’ blocks rather then ‘except’.

          >>> print(ast.dump(ast.parse("""
          ... try:
          ...    ...
          ... except* Exception:
          ...    ...
          ... """), indent=4))
          Module(
              body=[
                  TryStar(
                      body=[
                          Expr(
                              value=Constant(value=Ellipsis))],
                      handlers=[
                          ExceptHandler(
                              type=Name(id='Exception', ctx=Load()),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.11.

 -- Class: ast.ExceptHandler (type, name, body)

     A single ‘except’ clause.  ‘type’ is the exception type it will
     match, typically a *note Name: 1ac9. node (or ‘None’ for a
     catch-all ‘except:’ clause).  ‘name’ is a raw string for the name
     to hold the exception, or ‘None’ if the clause doesn’t have ‘as
     foo’.  ‘body’ is a list of nodes.

          >>> print(ast.dump(ast.parse("""\
          ... try:
          ...     a + 1
          ... except TypeError:
          ...     pass
          ... """), indent=4))
          Module(
              body=[
                  Try(
                      body=[
                          Expr(
                              value=BinOp(
                                  left=Name(id='a', ctx=Load()),
                                  op=Add(),
                                  right=Constant(value=1)))],
                      handlers=[
                          ExceptHandler(
                              type=Name(id='TypeError', ctx=Load()),
                              body=[
                                  Pass()])])])

 -- Class: ast.With (items, body, type_comment)

     A ‘with’ block.  ‘items’ is a list of *note withitem: 487a. nodes
     representing the context managers, and ‘body’ is the indented block
     inside the context.

      -- Attribute: type_comment

          ‘type_comment’ is an optional string with the type annotation
          as a comment.

 -- Class: ast.withitem (context_expr, optional_vars)

     A single context manager in a ‘with’ block.  ‘context_expr’ is the
     context manager, often a *note Call: 4830. node.  ‘optional_vars’
     is a *note Name: 1ac9, *note Tuple: 482a. or *note List: 4829. for
     the ‘as foo’ part, or ‘None’ if that isn’t used.

          >>> print(ast.dump(ast.parse("""\
          ... with a as b, c as d:
          ...    something(b, d)
          ... """), indent=4))
          Module(
              body=[
                  With(
                      items=[
                          withitem(
                              context_expr=Name(id='a', ctx=Load()),
                              optional_vars=Name(id='b', ctx=Store())),
                          withitem(
                              context_expr=Name(id='c', ctx=Load()),
                              optional_vars=Name(id='d', ctx=Store()))],
                      body=[
                          Expr(
                              value=Call(
                                  func=Name(id='something', ctx=Load()),
                                  args=[
                                      Name(id='b', ctx=Load()),
                                      Name(id='d', ctx=Load())]))])])


File: python.info,  Node: Pattern matching,  Next: Type annotations,  Prev: Control flow,  Up: Node classes

5.32.1.12 Pattern matching
..........................

 -- Class: ast.Match (subject, cases)

     A ‘match’ statement.  ‘subject’ holds the subject of the match (the
     object that is being matched against the cases) and ‘cases’
     contains an iterable of *note match_case: 487e. nodes with the
     different cases.

     Added in version 3.10.

 -- Class: ast.match_case (pattern, guard, body)

     A single case pattern in a ‘match’ statement.  ‘pattern’ contains
     the match pattern that the subject will be matched against.  Note
     that the *note AST: 1a6. nodes produced for patterns differ from
     those produced for expressions, even when they share the same
     syntax.

     The ‘guard’ attribute contains an expression that will be evaluated
     if the pattern matches the subject.

     ‘body’ contains a list of nodes to execute if the pattern matches
     and the result of evaluating the guard expression is true.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case [x] if x>0:
          ...         ...
          ...     case tuple():
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchSequence(
                                  patterns=[
                                      MatchAs(name='x')]),
                              guard=Compare(
                                  left=Name(id='x', ctx=Load()),
                                  ops=[
                                      Gt()],
                                  comparators=[
                                      Constant(value=0)]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          match_case(
                              pattern=MatchClass(
                                  cls=Name(id='tuple', ctx=Load())),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchValue (value)

     A match literal or value pattern that compares by equality.
     ‘value’ is an expression node.  Permitted value nodes are
     restricted as described in the match statement documentation.  This
     pattern succeeds if the match subject is equal to the evaluated
     value.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case "Relevant":
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchValue(
                                  value=Constant(value='Relevant')),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchSingleton (value)

     A match literal pattern that compares by identity.  ‘value’ is the
     singleton to be compared against: ‘None’, ‘True’, or ‘False’.  This
     pattern succeeds if the match subject is the given constant.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case None:
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchSingleton(value=None),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchSequence (patterns)

     A match sequence pattern.  ‘patterns’ contains the patterns to be
     matched against the subject elements if the subject is a sequence.
     Matches a variable length sequence if one of the subpatterns is a
     ‘MatchStar’ node, otherwise matches a fixed length sequence.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case [1, 2]:
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchSequence(
                                  patterns=[
                                      MatchValue(
                                          value=Constant(value=1)),
                                      MatchValue(
                                          value=Constant(value=2))]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchStar (name)

     Matches the rest of the sequence in a variable length match
     sequence pattern.  If ‘name’ is not ‘None’, a list containing the
     remaining sequence elements is bound to that name if the overall
     sequence pattern is successful.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case [1, 2, *rest]:
          ...         ...
          ...     case [*_]:
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchSequence(
                                  patterns=[
                                      MatchValue(
                                          value=Constant(value=1)),
                                      MatchValue(
                                          value=Constant(value=2)),
                                      MatchStar(name='rest')]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          match_case(
                              pattern=MatchSequence(
                                  patterns=[
                                      MatchStar()]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchMapping (keys, patterns, rest)

     A match mapping pattern.  ‘keys’ is a sequence of expression nodes.
     ‘patterns’ is a corresponding sequence of pattern nodes.  ‘rest’ is
     an optional name that can be specified to capture the remaining
     mapping elements.  Permitted key expressions are restricted as
     described in the match statement documentation.

     This pattern succeeds if the subject is a mapping, all evaluated
     key expressions are present in the mapping, and the value
     corresponding to each key matches the corresponding subpattern.  If
     ‘rest’ is not ‘None’, a dict containing the remaining mapping
     elements is bound to that name if the overall mapping pattern is
     successful.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case {1: _, 2: _}:
          ...         ...
          ...     case {**rest}:
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchMapping(
                                  keys=[
                                      Constant(value=1),
                                      Constant(value=2)],
                                  patterns=[
                                      MatchAs(),
                                      MatchAs()]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          match_case(
                              pattern=MatchMapping(rest='rest'),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchClass (cls, patterns, kwd_attrs, kwd_patterns)

     A match class pattern.  ‘cls’ is an expression giving the nominal
     class to be matched.  ‘patterns’ is a sequence of pattern nodes to
     be matched against the class defined sequence of pattern matching
     attributes.  ‘kwd_attrs’ is a sequence of additional attributes to
     be matched (specified as keyword arguments in the class pattern),
     ‘kwd_patterns’ are the corresponding patterns (specified as keyword
     values in the class pattern).

     This pattern succeeds if the subject is an instance of the
     nominated class, all positional patterns match the corresponding
     class-defined attributes, and any specified keyword attributes
     match their corresponding pattern.

     Note: classes may define a property that returns self in order to
     match a pattern node against the instance being matched.  Several
     builtin types are also matched that way, as described in the match
     statement documentation.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case Point2D(0, 0):
          ...         ...
          ...     case Point3D(x=0, y=0, z=0):
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchClass(
                                  cls=Name(id='Point2D', ctx=Load()),
                                  patterns=[
                                      MatchValue(
                                          value=Constant(value=0)),
                                      MatchValue(
                                          value=Constant(value=0))]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          match_case(
                              pattern=MatchClass(
                                  cls=Name(id='Point3D', ctx=Load()),
                                  kwd_attrs=[
                                      'x',
                                      'y',
                                      'z'],
                                  kwd_patterns=[
                                      MatchValue(
                                          value=Constant(value=0)),
                                      MatchValue(
                                          value=Constant(value=0)),
                                      MatchValue(
                                          value=Constant(value=0))]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchAs (pattern, name)

     A match “as-pattern”, capture pattern or wildcard pattern.
     ‘pattern’ contains the match pattern that the subject will be
     matched against.  If the pattern is ‘None’, the node represents a
     capture pattern (i.e a bare name) and will always succeed.

     The ‘name’ attribute contains the name that will be bound if the
     pattern is successful.  If ‘name’ is ‘None’, ‘pattern’ must also be
     ‘None’ and the node represents the wildcard pattern.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case [x] as y:
          ...         ...
          ...     case _:
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchAs(
                                  pattern=MatchSequence(
                                      patterns=[
                                          MatchAs(name='x')]),
                                  name='y'),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))]),
                          match_case(
                              pattern=MatchAs(),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.

 -- Class: ast.MatchOr (patterns)

     A match “or-pattern”.  An or-pattern matches each of its
     subpatterns in turn to the subject, until one succeeds.  The
     or-pattern is then deemed to succeed.  If none of the subpatterns
     succeed the or-pattern fails.  The ‘patterns’ attribute contains a
     list of match pattern nodes that will be matched against the
     subject.

          >>> print(ast.dump(ast.parse("""
          ... match x:
          ...     case [x] | (y):
          ...         ...
          ... """), indent=4))
          Module(
              body=[
                  Match(
                      subject=Name(id='x', ctx=Load()),
                      cases=[
                          match_case(
                              pattern=MatchOr(
                                  patterns=[
                                      MatchSequence(
                                          patterns=[
                                              MatchAs(name='x')]),
                                      MatchAs(name='y')]),
                              body=[
                                  Expr(
                                      value=Constant(value=Ellipsis))])])])

     Added in version 3.10.


File: python.info,  Node: Type annotations,  Next: Type parameters,  Prev: Pattern matching,  Up: Node classes

5.32.1.13 Type annotations
..........................

 -- Class: ast.TypeIgnore (lineno, tag)

     A ‘# type: ignore’ comment located at 'lineno'.  'tag' is the
     optional tag specified by the form ‘# type: ignore <tag>’.

          >>> print(ast.dump(ast.parse('x = 1 # type: ignore', type_comments=True), indent=4))
          Module(
              body=[
                  Assign(
                      targets=[
                          Name(id='x', ctx=Store())],
                      value=Constant(value=1))],
              type_ignores=[
                  TypeIgnore(lineno=1, tag='')])
          >>> print(ast.dump(ast.parse('x: bool = 1 # type: ignore[assignment]', type_comments=True), indent=4))
          Module(
              body=[
                  AnnAssign(
                      target=Name(id='x', ctx=Store()),
                      annotation=Name(id='bool', ctx=Load()),
                      value=Constant(value=1),
                      simple=1)],
              type_ignores=[
                  TypeIgnore(lineno=1, tag='[assignment]')])

          Note: ‘TypeIgnore’ nodes are not generated when the
          'type_comments' parameter is set to ‘False’ (default).  See
          *note ast.parse(): 1a8. for more details.

     Added in version 3.8.


File: python.info,  Node: Type parameters,  Next: Function and class definitions,  Prev: Type annotations,  Up: Node classes

5.32.1.14 Type parameters
.........................

*note Type parameters: 2b3. can exist on classes, functions, and type
aliases.

 -- Class: ast.TypeVar (name, bound, default_value)

     A *note typing.TypeVar: 15d.  ‘name’ is the name of the type
     variable.  ‘bound’ is the bound or constraints, if any.  If ‘bound’
     is a *note Tuple: 482a, it represents constraints; otherwise it
     represents the bound.  ‘default_value’ is the default value; if the
     ‘TypeVar’ has no default, this attribute will be set to ‘None’.

          >>> print(ast.dump(ast.parse("type Alias[T: int = bool] = list[T]"), indent=4))
          Module(
              body=[
                  TypeAlias(
                      name=Name(id='Alias', ctx=Store()),
                      type_params=[
                          TypeVar(
                              name='T',
                              bound=Name(id='int', ctx=Load()),
                              default_value=Name(id='bool', ctx=Load()))],
                      value=Subscript(
                          value=Name(id='list', ctx=Load()),
                          slice=Name(id='T', ctx=Load()),
                          ctx=Load()))])

     Added in version 3.12.

     Changed in version 3.13: Added the 'default_value' parameter.

 -- Class: ast.ParamSpec (name, default_value)

     A *note typing.ParamSpec: 15e.  ‘name’ is the name of the parameter
     specification.  ‘default_value’ is the default value; if the
     ‘ParamSpec’ has no default, this attribute will be set to ‘None’.

          >>> print(ast.dump(ast.parse("type Alias[**P = [int, str]] = Callable[P, int]"), indent=4))
          Module(
              body=[
                  TypeAlias(
                      name=Name(id='Alias', ctx=Store()),
                      type_params=[
                          ParamSpec(
                              name='P',
                              default_value=List(
                                  elts=[
                                      Name(id='int', ctx=Load()),
                                      Name(id='str', ctx=Load())],
                                  ctx=Load()))],
                      value=Subscript(
                          value=Name(id='Callable', ctx=Load()),
                          slice=Tuple(
                              elts=[
                                  Name(id='P', ctx=Load()),
                                  Name(id='int', ctx=Load())],
                              ctx=Load()),
                          ctx=Load()))])

     Added in version 3.12.

     Changed in version 3.13: Added the 'default_value' parameter.

 -- Class: ast.TypeVarTuple (name, default_value)

     A *note typing.TypeVarTuple: 15f.  ‘name’ is the name of the type
     variable tuple.  ‘default_value’ is the default value; if the
     ‘TypeVarTuple’ has no default, this attribute will be set to
     ‘None’.

          >>> print(ast.dump(ast.parse("type Alias[*Ts = ()] = tuple[*Ts]"), indent=4))
          Module(
              body=[
                  TypeAlias(
                      name=Name(id='Alias', ctx=Store()),
                      type_params=[
                          TypeVarTuple(
                              name='Ts',
                              default_value=Tuple(ctx=Load()))],
                      value=Subscript(
                          value=Name(id='tuple', ctx=Load()),
                          slice=Tuple(
                              elts=[
                                  Starred(
                                      value=Name(id='Ts', ctx=Load()),
                                      ctx=Load())],
                              ctx=Load()),
                          ctx=Load()))])

     Added in version 3.12.

     Changed in version 3.13: Added the 'default_value' parameter.


File: python.info,  Node: Function and class definitions,  Next: Async and await,  Prev: Type parameters,  Up: Node classes

5.32.1.15 Function and class definitions
........................................

 -- Class: ast.FunctionDef (name, args, body, decorator_list, returns,
          type_comment, type_params)

     A function definition.

        * ‘name’ is a raw string of the function name.

        * ‘args’ is an *note arguments: 488d. node.

        * ‘body’ is the list of nodes inside the function.

        * ‘decorator_list’ is the list of decorators to be applied,
          stored outermost first (i.e.  the first in the list will be
          applied last).

        * ‘returns’ is the return annotation.

        * ‘type_params’ is a list of *note type parameters: 486b.

      -- Attribute: type_comment

          ‘type_comment’ is an optional string with the type annotation
          as a comment.

     Changed in version 3.12: Added ‘type_params’.

 -- Class: ast.Lambda (args, body)

     ‘lambda’ is a minimal function definition that can be used inside
     an expression.  Unlike *note FunctionDef: 1817, ‘body’ holds a
     single node.

          >>> print(ast.dump(ast.parse('lambda x,y: ...'), indent=4))
          Module(
              body=[
                  Expr(
                      value=Lambda(
                          args=arguments(
                              args=[
                                  arg(arg='x'),
                                  arg(arg='y')]),
                          body=Constant(value=Ellipsis)))])

 -- Class: ast.arguments (posonlyargs, args, vararg, kwonlyargs,
          kw_defaults, kwarg, defaults)

     The arguments for a function.

        * ‘posonlyargs’, ‘args’ and ‘kwonlyargs’ are lists of *note arg:
          488f. nodes.

        * ‘vararg’ and ‘kwarg’ are single *note arg: 488f. nodes,
          referring to the ‘*args, **kwargs’ parameters.

        * ‘kw_defaults’ is a list of default values for keyword-only
          arguments.  If one is ‘None’, the corresponding argument is
          required.

        * ‘defaults’ is a list of default values for arguments that can
          be passed positionally.  If there are fewer defaults, they
          correspond to the last n arguments.

 -- Class: ast.arg (arg, annotation, type_comment)

     A single argument in a list.  ‘arg’ is a raw string of the argument
     name; ‘annotation’ is its annotation, such as a *note Name: 1ac9.
     node.

      -- Attribute: type_comment

          ‘type_comment’ is an optional string with the type annotation
          as a comment

          >>> print(ast.dump(ast.parse("""\
          ... @decorator1
          ... @decorator2
          ... def f(a: 'annotation', b=1, c=2, *d, e, f=3, **g) -> 'return annotation':
          ...     pass
          ... """), indent=4))
          Module(
              body=[
                  FunctionDef(
                      name='f',
                      args=arguments(
                          args=[
                              arg(
                                  arg='a',
                                  annotation=Constant(value='annotation')),
                              arg(arg='b'),
                              arg(arg='c')],
                          vararg=arg(arg='d'),
                          kwonlyargs=[
                              arg(arg='e'),
                              arg(arg='f')],
                          kw_defaults=[
                              None,
                              Constant(value=3)],
                          kwarg=arg(arg='g'),
                          defaults=[
                              Constant(value=1),
                              Constant(value=2)]),
                      body=[
                          Pass()],
                      decorator_list=[
                          Name(id='decorator1', ctx=Load()),
                          Name(id='decorator2', ctx=Load())],
                      returns=Constant(value='return annotation'))])

 -- Class: ast.Return (value)

     A ‘return’ statement.

          >>> print(ast.dump(ast.parse('return 4'), indent=4))
          Module(
              body=[
                  Return(
                      value=Constant(value=4))])

 -- Class: ast.Yield (value)
 -- Class: ast.YieldFrom (value)

     A ‘yield’ or ‘yield from’ expression.  Because these are
     expressions, they must be wrapped in an *note Expr: 4832. node if
     the value sent back is not used.

          >>> print(ast.dump(ast.parse('yield x'), indent=4))
          Module(
              body=[
                  Expr(
                      value=Yield(
                          value=Name(id='x', ctx=Load())))])

          >>> print(ast.dump(ast.parse('yield from x'), indent=4))
          Module(
              body=[
                  Expr(
                      value=YieldFrom(
                          value=Name(id='x', ctx=Load())))])

 -- Class: ast.Global (names)
 -- Class: ast.Nonlocal (names)

     ‘global’ and ‘nonlocal’ statements.  ‘names’ is a list of raw
     strings.

          >>> print(ast.dump(ast.parse('global x,y,z'), indent=4))
          Module(
              body=[
                  Global(
                      names=[
                          'x',
                          'y',
                          'z'])])

          >>> print(ast.dump(ast.parse('nonlocal x,y,z'), indent=4))
          Module(
              body=[
                  Nonlocal(
                      names=[
                          'x',
                          'y',
                          'z'])])

 -- Class: ast.ClassDef (name, bases, keywords, body, decorator_list,
          type_params)

     A class definition.

        * ‘name’ is a raw string for the class name

        * ‘bases’ is a list of nodes for explicitly specified base
          classes.

        * ‘keywords’ is a list of *note keyword: 4856. nodes,
          principally for ‘metaclass’.  Other keywords will be passed to
          the metaclass, as per PEP 3115(1).

        * ‘body’ is a list of nodes representing the code within the
          class definition.

        * ‘decorator_list’ is a list of nodes, as in *note FunctionDef:
          1817.

        * ‘type_params’ is a list of *note type parameters: 486b.

          >>> print(ast.dump(ast.parse("""\
          ... @decorator1
          ... @decorator2
          ... class Foo(base1, base2, metaclass=meta):
          ...     pass
          ... """), indent=4))
          Module(
              body=[
                  ClassDef(
                      name='Foo',
                      bases=[
                          Name(id='base1', ctx=Load()),
                          Name(id='base2', ctx=Load())],
                      keywords=[
                          keyword(
                              arg='metaclass',
                              value=Name(id='meta', ctx=Load()))],
                      body=[
                          Pass()],
                      decorator_list=[
                          Name(id='decorator1', ctx=Load()),
                          Name(id='decorator2', ctx=Load())])])

     Changed in version 3.12: Added ‘type_params’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3115/


File: python.info,  Node: Async and await,  Prev: Function and class definitions,  Up: Node classes

5.32.1.16 Async and await
.........................

 -- Class: ast.AsyncFunctionDef (name, args, body, decorator_list,
          returns, type_comment, type_params)

     An ‘async def’ function definition.  Has the same fields as *note
     FunctionDef: 1817.

     Changed in version 3.12: Added ‘type_params’.

 -- Class: ast.Await (value)

     An ‘await’ expression.  ‘value’ is what it waits for.  Only valid
     in the body of an *note AsyncFunctionDef: 1816.

     >>> print(ast.dump(ast.parse("""\
     ... async def f():
     ...     await other_func()
     ... """), indent=4))
     Module(
         body=[
             AsyncFunctionDef(
                 name='f',
                 args=arguments(),
                 body=[
                     Expr(
                         value=Await(
                             value=Call(
                                 func=Name(id='other_func', ctx=Load()))))])])

 -- Class: ast.AsyncFor (target, iter, body, orelse, type_comment)
 -- Class: ast.AsyncWith (items, body, type_comment)

     ‘async for’ loops and ‘async with’ context managers.  They have the
     same fields as *note For: 4871. and *note With: 4879, respectively.
     Only valid in the body of an *note AsyncFunctionDef: 1816.

     Note: When a string is parsed by *note ast.parse(): 1a8, operator
     nodes (subclasses of ‘ast.operator’, ‘ast.unaryop’, ‘ast.cmpop’,
     ‘ast.boolop’ and ‘ast.expr_context’) on the returned tree will be
     singletons.  Changes to one will be reflected in all other
     occurrences of the same value (e.g.  *note ast.Add: 483a.).


File: python.info,  Node: ast Helpers,  Next: Compiler Flags,  Prev: Node classes,  Up: ast — Abstract Syntax Trees

5.32.1.17 ‘ast’ Helpers
.......................

Apart from the node classes, the ‘ast’ module defines these utility
functions and classes for traversing abstract syntax trees:

 -- Function: ast.parse (source, filename='<unknown>', mode='exec', *,
          type_comments=False, feature_version=None, optimize=-1)

     Parse the source into an AST node.  Equivalent to ‘compile(source,
     filename, mode, flags=FLAGS_VALUE, optimize=optimize)’, where
     ‘FLAGS_VALUE’ is ‘ast.PyCF_ONLY_AST’ if ‘optimize <= 0’ and
     ‘ast.PyCF_OPTIMIZED_AST’ otherwise.

     If ‘type_comments=True’ is given, the parser is modified to check
     and return type comments as specified by PEP 484(1) and PEP 526(2).
     This is equivalent to adding *note ast.PyCF_TYPE_COMMENTS: 4899. to
     the flags passed to *note compile(): 192.  This will report syntax
     errors for misplaced type comments.  Without this flag, type
     comments will be ignored, and the ‘type_comment’ field on selected
     AST nodes will always be ‘None’.  In addition, the locations of ‘#
     type: ignore’ comments will be returned as the ‘type_ignores’
     attribute of *note Module: 4821. (otherwise it is always an empty
     list).

     In addition, if ‘mode’ is ‘'func_type'’, the input syntax is
     modified to correspond to PEP 484(3) “signature type comments”,
     e.g.  ‘(str, int) -> List[str]’.

     Setting ‘feature_version’ to a tuple ‘(major, minor)’ will result
     in a “best-effort” attempt to parse using that Python version’s
     grammar.  For example, setting ‘feature_version=(3, 9)’ will
     attempt to disallow parsing of *note match: 813. statements.
     Currently ‘major’ must equal to ‘3’.  The lowest supported version
     is ‘(3, 7)’ (and this may increase in future Python versions); the
     highest is ‘sys.version_info[0:2]’.  “Best-effort” attempt means
     there is no guarantee that the parse (or success of the parse) is
     the same as when run on the Python version corresponding to
     ‘feature_version’.

     If source contains a null character (‘\0’), *note ValueError: 202.
     is raised.

          Warning: Note that successfully parsing source code into an
          AST object doesn’t guarantee that the source code provided is
          valid Python code that can be executed as the compilation step
          can raise further *note SyntaxError: 18d. exceptions.  For
          instance, the source ‘return 42’ generates a valid AST node
          for a return statement, but it cannot be compiled alone (it
          needs to be inside a function node).

          In particular, *note ast.parse(): 1a8. won’t do any scoping
          checks, which the compilation step does.

          Warning: It is possible to crash the Python interpreter with a
          sufficiently large/complex string due to stack depth
          limitations in Python’s AST compiler.

     Changed in version 3.8: Added ‘type_comments’, ‘mode='func_type'’
     and ‘feature_version’.

     Changed in version 3.13: The minimum supported version for
     ‘feature_version’ is now ‘(3, 7)’.  The ‘optimize’ argument was
     added.

 -- Function: ast.unparse (ast_obj)

     Unparse an *note ast.AST: 1a6. object and generate a string with
     code that would produce an equivalent ‘ast.AST’ object if parsed
     back with *note ast.parse(): 1a8.

          Warning: The produced code string will not necessarily be
          equal to the original code that generated the *note ast.AST:
          1a6. object (without any compiler optimizations, such as
          constant tuples/frozensets).

          Warning: Trying to unparse a highly complex expression would
          result with *note RecursionError: d96.

     Added in version 3.9.

 -- Function: ast.literal_eval (node_or_string)

     Evaluate an expression node or a string containing only a Python
     literal or container display.  The string or node provided may only
     consist of the following Python literal structures: strings, bytes,
     numbers, tuples, lists, dicts, sets, booleans, ‘None’ and
     ‘Ellipsis’.

     This can be used for evaluating strings containing Python values
     without the need to parse the values oneself.  It is not capable of
     evaluating arbitrarily complex expressions, for example involving
     operators or indexing.

     This function had been documented as “safe” in the past without
     defining what that meant.  That was misleading.  This is
     specifically designed not to execute Python code, unlike the more
     general *note eval(): 180.  There is no namespace, no name lookups,
     or ability to call out.  But it is not free from attack: A
     relatively small input can lead to memory exhaustion or to C stack
     exhaustion, crashing the process.  There is also the possibility
     for excessive CPU consumption denial of service on some inputs.
     Calling it on untrusted data is thus not recommended.

          Warning: It is possible to crash the Python interpreter due to
          stack depth limitations in Python’s AST compiler.

          It can raise *note ValueError: 202, *note TypeError: 2c3,
          *note SyntaxError: 18d, *note MemoryError: 15ab. and *note
          RecursionError: d96. depending on the malformed input.

     Changed in version 3.2: Now allows bytes and set literals.

     Changed in version 3.9: Now supports creating empty sets with
     ‘'set()'’.

     Changed in version 3.10: For string inputs, leading spaces and tabs
     are now stripped.

 -- Function: ast.get_docstring (node, clean=True)

     Return the docstring of the given 'node' (which must be a *note
     FunctionDef: 1817, *note AsyncFunctionDef: 1816, *note ClassDef:
     1815, or *note Module: 4821. node), or ‘None’ if it has no
     docstring.  If 'clean' is true, clean up the docstring’s
     indentation with *note inspect.cleandoc(): 17c5.

     Changed in version 3.5: *note AsyncFunctionDef: 1816. is now
     supported.

 -- Function: ast.get_source_segment (source, node, *, padded=False)

     Get source code segment of the 'source' that generated 'node'.  If
     some location information (*note lineno: 481a, *note end_lineno:
     481c, *note col_offset: 481b, or *note end_col_offset: 481d.) is
     missing, return ‘None’.

     If 'padded' is ‘True’, the first line of a multi-line statement
     will be padded with spaces to match its original position.

     Added in version 3.8.

 -- Function: ast.fix_missing_locations (node)

     When you compile a node tree with *note compile(): 192, the
     compiler expects *note lineno: 481a. and *note col_offset: 481b.
     attributes for every node that supports them.  This is rather
     tedious to fill in for generated nodes, so this helper adds these
     attributes recursively where not already set, by setting them to
     the values of the parent node.  It works recursively starting at
     'node'.

 -- Function: ast.increment_lineno (node, n=1)

     Increment the line number and end line number of each node in the
     tree starting at 'node' by 'n'.  This is useful to “move code” to a
     different location in a file.

 -- Function: ast.copy_location (new_node, old_node)

     Copy source location (*note lineno: 481a, *note col_offset: 481b,
     *note end_lineno: 481c, and *note end_col_offset: 481d.) from
     'old_node' to 'new_node' if possible, and return 'new_node'.

 -- Function: ast.iter_fields (node)

     Yield a tuple of ‘(fieldname, value)’ for each field in
     ‘node._fields’ that is present on 'node'.

 -- Function: ast.iter_child_nodes (node)

     Yield all direct child nodes of 'node', that is, all fields that
     are nodes and all items of fields that are lists of nodes.

 -- Function: ast.walk (node)

     Recursively yield all descendant nodes in the tree starting at
     'node' (including 'node' itself), in no specified order.  This is
     useful if you only want to modify nodes in place and don’t care
     about the context.

 -- Class: ast.NodeVisitor

     A node visitor base class that walks the abstract syntax tree and
     calls a visitor function for every node found.  This function may
     return a value which is forwarded by the *note visit(): 489f.
     method.

     This class is meant to be subclassed, with the subclass adding
     visitor methods.

      -- Method: visit (node)

          Visit a node.  The default implementation calls the method
          called ‘self.visit_CLASSNAME’ where 'classname' is the name of
          the node class, or *note generic_visit(): 48a0. if that method
          doesn’t exist.

      -- Method: generic_visit (node)

          This visitor calls *note visit(): 489f. on all children of the
          node.

          Note that child nodes of nodes that have a custom visitor
          method won’t be visited unless the visitor calls
          ‘generic_visit()’ or visits them itself.

      -- Method: visit_Constant (node)

          Handles all constant nodes.

     Don’t use the ‘NodeVisitor’ if you want to apply changes to nodes
     during traversal.  For this a special visitor exists (*note
     NodeTransformer: 48a1.) that allows modifications.

     Deprecated since version 3.8: Methods ‘visit_Num()’, ‘visit_Str()’,
     ‘visit_Bytes()’, ‘visit_NameConstant()’ and ‘visit_Ellipsis()’ are
     deprecated now and will not be called in future Python versions.
     Add the *note visit_Constant(): a7d. method to handle all constant
     nodes.

 -- Class: ast.NodeTransformer

     A *note NodeVisitor: a7c. subclass that walks the abstract syntax
     tree and allows modification of nodes.

     The ‘NodeTransformer’ will walk the AST and use the return value of
     the visitor methods to replace or remove the old node.  If the
     return value of the visitor method is ‘None’, the node will be
     removed from its location, otherwise it is replaced with the return
     value.  The return value may be the original node in which case no
     replacement takes place.

     Here is an example transformer that rewrites all occurrences of
     name lookups (‘foo’) to ‘data['foo']’:

          class RewriteName(NodeTransformer):

              def visit_Name(self, node):
                  return Subscript(
                      value=Name(id='data', ctx=Load()),
                      slice=Constant(value=node.id),
                      ctx=node.ctx
                  )

     Keep in mind that if the node you’re operating on has child nodes
     you must either transform the child nodes yourself or call the
     *note generic_visit(): 48a0. method for the node first.

     For nodes that were part of a collection of statements (that
     applies to all statement nodes), the visitor may also return a list
     of nodes rather than just a single node.

     If ‘NodeTransformer’ introduces new nodes (that weren’t part of
     original tree) without giving them location information (such as
     *note lineno: 481a.), *note fix_missing_locations(): 489a. should
     be called with the new sub-tree to recalculate the location
     information:

          tree = ast.parse('foo', mode='eval')
          new_tree = fix_missing_locations(RewriteName().visit(tree))

     Usually you use the transformer like this:

          node = YourTransformer().visit(node)

 -- Function: ast.dump (node, annotate_fields=True,
          include_attributes=False, *, indent=None, show_empty=False)

     Return a formatted dump of the tree in 'node'.  This is mainly
     useful for debugging purposes.  If 'annotate_fields' is true (by
     default), the returned string will show the names and the values
     for fields.  If 'annotate_fields' is false, the result string will
     be more compact by omitting unambiguous field names.  Attributes
     such as line numbers and column offsets are not dumped by default.
     If this is wanted, 'include_attributes' can be set to true.

     If 'indent' is a non-negative integer or string, then the tree will
     be pretty-printed with that indent level.  An indent level of 0,
     negative, or ‘""’ will only insert newlines.  ‘None’ (the default)
     selects the single line representation.  Using a positive integer
     indent indents that many spaces per level.  If 'indent' is a string
     (such as ‘"\t"’), that string is used to indent each level.

     If 'show_empty' is false (the default), optional empty lists will
     be omitted from the output.  Optional ‘None’ values are always
     omitted.

     Changed in version 3.9: Added the 'indent' option.

     Changed in version 3.13: Added the 'show_empty' option.

          >>> print(ast.dump(ast.parse("""\
          ... async def f():
          ...     await other_func()
          ... """), indent=4, show_empty=True))
          Module(
              body=[
                  AsyncFunctionDef(
                      name='f',
                      args=arguments(
                          posonlyargs=[],
                          args=[],
                          kwonlyargs=[],
                          kw_defaults=[],
                          defaults=[]),
                      body=[
                          Expr(
                              value=Await(
                                  value=Call(
                                      func=Name(id='other_func', ctx=Load()),
                                      args=[],
                                      keywords=[])))],
                      decorator_list=[],
                      type_params=[])],
              type_ignores=[])

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0526/

   (3) https://peps.python.org/pep-0484/


File: python.info,  Node: Compiler Flags,  Next: Command-Line Usage<4>,  Prev: ast Helpers,  Up: ast — Abstract Syntax Trees

5.32.1.18 Compiler Flags
........................

The following flags may be passed to *note compile(): 192. in order to
change effects on the compilation of a program:

 -- Data: ast.PyCF_ALLOW_TOP_LEVEL_AWAIT

     Enables support for top-level ‘await’, ‘async for’, ‘async with’
     and async comprehensions.

     Added in version 3.8.

 -- Data: ast.PyCF_ONLY_AST

     Generates and returns an abstract syntax tree instead of returning
     a compiled code object.

 -- Data: ast.PyCF_OPTIMIZED_AST

     The returned AST is optimized according to the 'optimize' argument
     in *note compile(): 192. or *note ast.parse(): 1a8.

     Added in version 3.13.

 -- Data: ast.PyCF_TYPE_COMMENTS

     Enables support for PEP 484(1) and PEP 526(2) style type comments
     (‘# type: <type>’, ‘# type: ignore <stuff>’).

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0526/


File: python.info,  Node: Command-Line Usage<4>,  Prev: Compiler Flags,  Up: ast — Abstract Syntax Trees

5.32.1.19 Command-Line Usage
............................

Added in version 3.9.

The ‘ast’ module can be executed as a script from the command line.  It
is as simple as:

     python -m ast [-m <mode>] [-a] [infile]

The following options are accepted:

 -- Option: -h, --help

     Show the help message and exit.

 -- Option: -m <mode>
 -- Option: --mode <mode>

     Specify what kind of code must be compiled, like the 'mode'
     argument in *note parse(): 1a8.

 -- Option: --no-type-comments

     Don’t parse type comments.

 -- Option: -a, --include-attributes

     Include attributes such as line numbers and column offsets.

 -- Option: -i <indent>
 -- Option: --indent <indent>

     Indentation of nodes in AST (number of spaces).

If ‘infile’ is specified its contents are parsed to AST and dumped to
stdout.  Otherwise, the content is read from stdin.

See also
........

Green Tree Snakes(1), an external documentation resource, has good
details on working with Python ASTs.

ASTTokens(2) annotates Python ASTs with the positions of tokens and text
in the source code that generated them.  This is helpful for tools that
make source code transformations.

leoAst.py(3) unifies the token-based and parse-tree-based views of
python programs by inserting two-way links between tokens and ast nodes.

LibCST(4) parses code as a Concrete Syntax Tree that looks like an ast
tree and keeps all formatting details.  It’s useful for building
automated refactoring (codemod) applications and linters.

Parso(5) is a Python parser that supports error recovery and round-trip
parsing for different Python versions (in multiple Python versions).
Parso is also able to list multiple syntax errors in your Python file.

   ---------- Footnotes ----------

   (1) https://greentreesnakes.readthedocs.io/

   (2) https://asttokens.readthedocs.io/en/latest/user-guide.html

   (3) https://leo-editor.github.io/leo-editor/appendices.html#leoast-py

   (4) https://libcst.readthedocs.io/

   (5) https://parso.readthedocs.io


File: python.info,  Node: symtable — Access to the compiler’s symbol tables,  Next: token — Constants used with Python parse trees,  Prev: ast — Abstract Syntax Trees,  Up: Python Language Services

5.32.2 ‘symtable’ — Access to the compiler’s symbol tables
----------------------------------------------------------

'Source code:' Lib/symtable.py(1)

__________________________________________________________________

Symbol tables are generated by the compiler from AST just before
bytecode is generated.  The symbol table is responsible for calculating
the scope of every identifier in the code.  ‘symtable’ provides an
interface to examine these tables.

* Menu:

* Generating Symbol Tables::
* Examining Symbol Tables::
* Command-Line Usage: Command-Line Usage<5>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/symtable.py


File: python.info,  Node: Generating Symbol Tables,  Next: Examining Symbol Tables,  Up: symtable — Access to the compiler’s symbol tables

5.32.2.1 Generating Symbol Tables
.................................

 -- Function: symtable.symtable (code, filename, compile_type)

     Return the toplevel *note SymbolTable: 48b4. for the Python source
     'code'.  'filename' is the name of the file containing the code.
     'compile_type' is like the 'mode' argument to *note compile(): 192.


File: python.info,  Node: Examining Symbol Tables,  Next: Command-Line Usage<5>,  Prev: Generating Symbol Tables,  Up: symtable — Access to the compiler’s symbol tables

5.32.2.2 Examining Symbol Tables
................................

 -- Class: symtable.SymbolTableType

     An enumeration indicating the type of a *note SymbolTable: 48b4.
     object.

      -- Attribute: MODULE = "module"

          Used for the symbol table of a module.

      -- Attribute: FUNCTION = "function"

          Used for the symbol table of a function.

      -- Attribute: CLASS = "class"

          Used for the symbol table of a class.

     The following members refer to different flavors of *note
     annotation scopes: 188.

      -- Attribute: ANNOTATION = "annotation"

          Used for annotations if ‘from __future__ import annotations’
          is active.

      -- Attribute: TYPE_ALIAS = "type alias"

          Used for the symbol table of *note type: 43b. constructions.

      -- Attribute: TYPE_PARAMETERS = "type parameters"

          Used for the symbol table of *note generic functions: 456. or
          *note generic classes: 455.

      -- Attribute: TYPE_VARIABLE = "type variable"

          Used for the symbol table of the bound, the constraint tuple
          or the default value of a single type variable in the formal
          sense, i.e., a TypeVar, a TypeVarTuple or a ParamSpec object
          (the latter two do not support a bound or a constraint tuple).

     Added in version 3.13.

 -- Class: symtable.SymbolTable

     A namespace table for a block.  The constructor is not public.

      -- Method: get_type ()

          Return the type of the symbol table.  Possible values are
          members of the *note SymbolTableType: 1716. enumeration.

          Changed in version 3.12: Added ‘'annotation'’, ‘'TypeVar
          bound'’, ‘'type alias'’, and ‘'type parameter'’ as possible
          return values.

          Changed in version 3.13: Return values are members of the
          *note SymbolTableType: 1716. enumeration.

          The exact values of the returned string may change in the
          future, and thus, it is recommended to use *note
          SymbolTableType: 1716. members instead of hard-coded strings.

      -- Method: get_id ()

          Return the table’s identifier.

      -- Method: get_name ()

          Return the table’s name.  This is the name of the class if the
          table is for a class, the name of the function if the table is
          for a function, or ‘'top'’ if the table is global (*note
          get_type(): 1717. returns ‘'module'’).  For type parameter
          scopes (which are used for generic classes, functions, and
          type aliases), it is the name of the underlying class,
          function, or type alias.  For type alias scopes, it is the
          name of the type alias.  For *note TypeVar: 15d. bound scopes,
          it is the name of the ‘TypeVar’.

      -- Method: get_lineno ()

          Return the number of the first line in the block this table
          represents.

      -- Method: is_optimized ()

          Return ‘True’ if the locals in this table can be optimized.

      -- Method: is_nested ()

          Return ‘True’ if the block is a nested class or function.

      -- Method: has_children ()

          Return ‘True’ if the block has nested namespaces within it.
          These can be obtained with *note get_children(): 48c3.

      -- Method: get_identifiers ()

          Return a view object containing the names of symbols in the
          table.  See the *note documentation of view objects: 23fb.

      -- Method: lookup (name)

          Lookup 'name' in the table and return a *note Symbol: 17de.
          instance.

      -- Method: get_symbols ()

          Return a list of *note Symbol: 17de. instances for names in
          the table.

      -- Method: get_children ()

          Return a list of the nested symbol tables.

 -- Class: symtable.Function

     A namespace for a function or method.  This class inherits from
     *note SymbolTable: 48b4.

      -- Method: get_parameters ()

          Return a tuple containing names of parameters to this
          function.

      -- Method: get_locals ()

          Return a tuple containing names of locals in this function.

      -- Method: get_globals ()

          Return a tuple containing names of globals in this function.

      -- Method: get_nonlocals ()

          Return a tuple containing names of explicitly declared
          nonlocals in this function.

      -- Method: get_frees ()

          Return a tuple containing names of *note free (closure)
          variables: 20f4. in this function.

 -- Class: symtable.Class

     A namespace of a class.  This class inherits from *note
     SymbolTable: 48b4.

      -- Method: get_methods ()

          Return a tuple containing the names of method-like functions
          declared in the class.

          Here, the term ‘method’ designates 'any' function defined in
          the class body via *note def: 14a9. or *note async def: 5d4.

          Functions defined in a deeper scope (e.g., in an inner class)
          are not picked up by ‘get_methods()’.

          For example:

               >>> import symtable
               >>> st = symtable.symtable('''
               ... def outer(): pass
               ...
               ... class A:
               ...    def f():
               ...        def w(): pass
               ...
               ...    def g(self): pass
               ...
               ...    @classmethod
               ...    async def h(cls): pass
               ...
               ...    global outer
               ...    def outer(self): pass
               ... ''', 'test', 'exec')
               >>> class_A = st.get_children()[1]
               >>> class_A.get_methods()
               ('f', 'g', 'h')

          Although ‘A().f()’ raises *note TypeError: 2c3. at runtime,
          ‘A.f’ is still considered as a method-like function.

 -- Class: symtable.Symbol

     An entry in a *note SymbolTable: 48b4. corresponding to an
     identifier in the source.  The constructor is not public.

      -- Method: get_name ()

          Return the symbol’s name.

      -- Method: is_referenced ()

          Return ‘True’ if the symbol is used in its block.

      -- Method: is_imported ()

          Return ‘True’ if the symbol is created from an import
          statement.

      -- Method: is_parameter ()

          Return ‘True’ if the symbol is a parameter.

      -- Method: is_global ()

          Return ‘True’ if the symbol is global.

      -- Method: is_nonlocal ()

          Return ‘True’ if the symbol is nonlocal.

      -- Method: is_declared_global ()

          Return ‘True’ if the symbol is declared global with a global
          statement.

      -- Method: is_local ()

          Return ‘True’ if the symbol is local to its block.

      -- Method: is_annotated ()

          Return ‘True’ if the symbol is annotated.

          Added in version 3.6.

      -- Method: is_free ()

          Return ‘True’ if the symbol is referenced in its block, but
          not assigned to.

      -- Method: is_assigned ()

          Return ‘True’ if the symbol is assigned to in its block.

      -- Method: is_namespace ()

          Return ‘True’ if name binding introduces new namespace.

          If the name is used as the target of a function or class
          statement, this will be true.

          For example:

               >>> table = symtable.symtable("def some_func(): pass", "string", "exec")
               >>> table.lookup("some_func").is_namespace()
               True

          Note that a single name can be bound to multiple objects.  If
          the result is ‘True’, the name may also be bound to other
          objects, like an int or list, that does not introduce a new
          namespace.

      -- Method: get_namespaces ()

          Return a list of namespaces bound to this name.

      -- Method: get_namespace ()

          Return the namespace bound to this name.  If more than one or
          no namespace is bound to this name, a *note ValueError: 202.
          is raised.


File: python.info,  Node: Command-Line Usage<5>,  Prev: Examining Symbol Tables,  Up: symtable — Access to the compiler’s symbol tables

5.32.2.3 Command-Line Usage
...........................

Added in version 3.13.

The ‘symtable’ module can be executed as a script from the command line.

     python -m symtable [infile...]

Symbol tables are generated for the specified Python source files and
dumped to stdout.  If no input file is specified, the content is read
from stdin.


File: python.info,  Node: token — Constants used with Python parse trees,  Next: keyword — Testing for Python keywords,  Prev: symtable — Access to the compiler’s symbol tables,  Up: Python Language Services

5.32.3 ‘token’ — Constants used with Python parse trees
-------------------------------------------------------

'Source code:' Lib/token.py(1)

__________________________________________________________________

This module provides constants which represent the numeric values of
leaf nodes of the parse tree (terminal tokens).  Refer to the file
‘Grammar/Tokens’ in the Python distribution for the definitions of the
names in the context of the language grammar.  The specific numeric
values which the names map to may change between Python versions.

The module also provides a mapping from numeric codes to names and some
functions.  The functions mirror definitions in the Python C header
files.

Note that a token’s value may depend on tokenizer options.  For example,
a ‘"+"’ token may be reported as either *note PLUS: 48df. or *note OP:
48e0, or a ‘"match"’ token may be either *note NAME: 48e1. or *note
SOFT_KEYWORD: 48e2.

 -- Data: token.tok_name

     Dictionary mapping the numeric values of the constants defined in
     this module back to name strings, allowing more human-readable
     representation of parse trees to be generated.

 -- Function: token.ISTERMINAL (x)

     Return ‘True’ for terminal token values.

 -- Function: token.ISNONTERMINAL (x)

     Return ‘True’ for non-terminal token values.

 -- Function: token.ISEOF (x)

     Return ‘True’ if 'x' is the marker indicating the end of input.

The token constants are:

 -- Data: token.NAME

     Token value that indicates an *note identifier: 2040.  Note that
     keywords are also initially tokenized as ‘NAME’ tokens.

 -- Data: token.NUMBER

     Token value that indicates a *note numeric literal: 2071.

 -- Data: token.STRING

     Token value that indicates a *note string or byte literal: 2050,
     excluding *note formatted string literals: 9b4.  The token string
     is not interpreted: it includes the surrounding quotation marks and
     the prefix (if given); backslashes are included literally, without
     processing escape sequences.

 -- Data: token.OP

     A generic token value that indicates an *note operator: 208b. or
     *note delimiter: 208c.

     'CPython implementation detail:' This value is only reported by the
     *note tokenize: fb. module.  Internally, the tokenizer uses *note
     exact token types: 48e9. instead.

 -- Data: token.COMMENT

     Token value used to indicate a comment.  The parser ignores
     ‘COMMENT’ tokens.

 -- Data: token.NEWLINE

     Token value that indicates the end of a *note logical line: 202d.

 -- Data: token.NL

     Token value used to indicate a non-terminating newline.  ‘NL’
     tokens are generated when a logical line of code is continued over
     multiple physical lines.  The parser ignores ‘NL’ tokens.

 -- Data: token.INDENT

     Token value used at the beginning of a *note logical line: 202d. to
     indicate the start of an *note indented block: 203b.

 -- Data: token.DEDENT

     Token value used at the beginning of a *note logical line: 202d. to
     indicate the end of an *note indented block: 203b.

 -- Data: token.FSTRING_START

     Token value used to indicate the beginning of an *note f-string
     literal: 9b4.

     'CPython implementation detail:' The token string includes the
     prefix and the opening quote(s), but none of the contents of the
     literal.

 -- Data: token.FSTRING_MIDDLE

     Token value used for literal text inside an *note f-string literal:
     9b4, including format specifications.

     'CPython implementation detail:' Replacement fields (that is, the
     non-literal parts of f-strings) use the same tokens as other
     expressions, and are delimited by *note LBRACE: 48f0, *note RBRACE:
     48f1, *note EXCLAMATION: 48f2. and *note COLON: 48f3. tokens.

 -- Data: token.FSTRING_END

     Token value used to indicate the end of a *note f-string: 9b4.

     'CPython implementation detail:' The token string contains the
     closing quote(s).

 -- Data: token.ENDMARKER

     Token value that indicates the end of input.

 -- Data: token.ENCODING

     Token value that indicates the encoding used to decode the source
     bytes into text.  The first token returned by *note
     tokenize.tokenize(): 4dc. will always be an ‘ENCODING’ token.

     'CPython implementation detail:' This token type isn’t used by the
     C tokenizer but is needed for the *note tokenize: fb. module.

The following token types are not produced by the *note tokenize: fb.
module, and are defined for special uses in the tokenizer or parser:

 -- Data: token.TYPE_IGNORE

     Token value indicating that a ‘type: ignore’ comment was
     recognized.  Such tokens are produced instead of regular *note
     COMMENT: 48ea. tokens only with the *note PyCF_TYPE_COMMENTS: 4899.
     flag.

 -- Data: token.TYPE_COMMENT

     Token value indicating that a type comment was recognized.  Such
     tokens are produced instead of regular *note COMMENT: 48ea. tokens
     only with the *note PyCF_TYPE_COMMENTS: 4899. flag.

 -- Data: token.SOFT_KEYWORD

     Token value indicating a *note soft keyword: 812.

     The tokenizer never produces this value.  To check for a soft
     keyword, pass a *note NAME: 48e1. token’s string to *note
     keyword.issoftkeyword(): 48f9.

 -- Data: token.ERRORTOKEN

     Token value used to indicate wrong input.

     The *note tokenize: fb. module generally indicates errors by
     raising exceptions instead of emitting this token.  It can also
     emit tokens such as *note OP: 48e0. or *note NAME: 48e1. with
     strings that are later rejected by the parser.
The remaining tokens represent specific *note operators: 208b. and *note
delimiters: 208c.  (The *note tokenize: fb. module reports these as
*note OP: 48e0.; see ‘exact_type’ in the ‘tokenize’ documentation for
details.)

Token                                                  Value
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- Data: token.LPAR                                   ‘"("’
                                                       
                                                       
 -- Data: token.RPAR                                   ‘")"’
                                                       
                                                       
 -- Data: token.LSQB                                   ‘"["’
                                                       
                                                       
 -- Data: token.RSQB                                   ‘"]"’
                                                       
                                                       
 -- Data: token.COLON                                  ‘":"’
                                                       
                                                       
 -- Data: token.COMMA                                  ‘","’
                                                       
                                                       
 -- Data: token.SEMI                                   ‘";"’
                                                       
                                                       
 -- Data: token.PLUS                                   ‘"+"’
                                                       
                                                       
 -- Data: token.MINUS                                  ‘"-"’
                                                       
                                                       
 -- Data: token.STAR                                   ‘"*"’
                                                       
                                                       
 -- Data: token.SLASH                                  ‘"/"’
                                                       
                                                       
 -- Data: token.VBAR                                   ‘"|"’
                                                       
                                                       
 -- Data: token.AMPER                                  ‘"&"’
                                                       
                                                       
 -- Data: token.LESS                                   ‘"<"’
                                                       
                                                       
 -- Data: token.GREATER                                ‘">"’
                                                       
                                                       
 -- Data: token.EQUAL                                  ‘"="’
                                                       
                                                       
 -- Data: token.DOT                                    ‘"."’
                                                       
                                                       
 -- Data: token.PERCENT                                ‘"%"’
                                                       
                                                       
 -- Data: token.LBRACE                                 ‘"{"’
                                                       
                                                       
 -- Data: token.RBRACE                                 ‘"}"’
                                                       
                                                       
 -- Data: token.EQEQUAL                                ‘"=="’
                                                       
                                                       
 -- Data: token.NOTEQUAL                               ‘"!="’
                                                       
                                                       
 -- Data: token.LESSEQUAL                              ‘"<="’
                                                       
                                                       
 -- Data: token.GREATEREQUAL                           ‘">="’
                                                       
                                                       
 -- Data: token.TILDE                                  ‘"~"’
                                                       
                                                       
 -- Data: token.CIRCUMFLEX                             ‘"^"’
                                                       
                                                       
 -- Data: token.LEFTSHIFT                              ‘"<<"’
                                                       
                                                       
 -- Data: token.RIGHTSHIFT                             ‘">>"’
                                                       
                                                       
 -- Data: token.DOUBLESTAR                             ‘"**"’
                                                       
                                                       
 -- Data: token.PLUSEQUAL                              ‘"+="’
                                                       
                                                       
 -- Data: token.MINEQUAL                               ‘"-="’
                                                       
                                                       
 -- Data: token.STAREQUAL                              ‘"*="’
                                                       
                                                       
 -- Data: token.SLASHEQUAL                             ‘"/="’
                                                       
                                                       
 -- Data: token.PERCENTEQUAL                           ‘"%="’
                                                       
                                                       
 -- Data: token.AMPEREQUAL                             ‘"&="’
                                                       
                                                       
 -- Data: token.VBAREQUAL                              ‘"|="’
                                                       
                                                       
 -- Data: token.CIRCUMFLEXEQUAL                        ‘"^="’
                                                       
                                                       
 -- Data: token.LEFTSHIFTEQUAL                         ‘"<<="’
                                                       
                                                       
 -- Data: token.RIGHTSHIFTEQUAL                        ‘">>="’
                                                       
                                                       
 -- Data: token.DOUBLESTAREQUAL                        ‘"**="’
                                                       
                                                       
 -- Data: token.DOUBLESLASH                            ‘"//"’
                                                       
                                                       
 -- Data: token.DOUBLESLASHEQUAL                       ‘"//="’
                                                       
                                                       
 -- Data: token.AT                                     ‘"@"’
                                                       
                                                       
 -- Data: token.ATEQUAL                                ‘"@="’
                                                       
                                                       
 -- Data: token.RARROW                                 ‘"->"’
                                                       
                                                       
 -- Data: token.ELLIPSIS                               ‘"..."’
                                                       
                                                       
 -- Data: token.COLONEQUAL                             ‘":="’
                                                       
                                                       
 -- Data: token.EXCLAMATION                            ‘"!"’
                                                       

The following non-token constants are provided:

 -- Data: token.N_TOKENS

     The number of token types defined in this module.

 -- Data: token.EXACT_TOKEN_TYPES

     A dictionary mapping the string representation of a token to its
     numeric code.

     Added in version 3.8.

Changed in version 3.5: Added ‘AWAIT’ and ‘ASYNC’ tokens.

Changed in version 3.7: Added *note COMMENT: 48ea, *note NL: 48ec. and
*note ENCODING: 48f6. tokens.

Changed in version 3.7: Removed ‘AWAIT’ and ‘ASYNC’ tokens.  “async” and
“await” are now tokenized as *note NAME: 48e1. tokens.

Changed in version 3.8: Added *note TYPE_COMMENT: 48f8, *note
TYPE_IGNORE: 48f7, *note COLONEQUAL: 4925.  Added ‘AWAIT’ and ‘ASYNC’
tokens back (they’re needed to support parsing older Python versions for
*note ast.parse(): 1a8. with ‘feature_version’ set to 6 or lower).

Changed in version 3.12: Added *note EXCLAMATION: 48f2.

Changed in version 3.13: Removed ‘AWAIT’ and ‘ASYNC’ tokens again.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/token.py


File: python.info,  Node: keyword — Testing for Python keywords,  Next: tokenize — Tokenizer for Python source,  Prev: token — Constants used with Python parse trees,  Up: Python Language Services

5.32.4 ‘keyword’ — Testing for Python keywords
----------------------------------------------

'Source code:' Lib/keyword.py(1)

__________________________________________________________________

This module allows a Python program to determine if a string is a *note
keyword: 2048. or *note soft keyword: 812.

 -- Function: keyword.iskeyword (s)

     Return ‘True’ if 's' is a Python *note keyword: 2048.

 -- Data: keyword.kwlist

     Sequence containing all the *note keywords: 2048. defined for the
     interpreter.  If any keywords are defined to only be active when
     particular *note __future__: 0. statements are in effect, these
     will be included as well.

 -- Function: keyword.issoftkeyword (s)

     Return ‘True’ if 's' is a Python *note soft keyword: 812.

     Added in version 3.9.

 -- Data: keyword.softkwlist

     Sequence containing all the *note soft keywords: 812. defined for
     the interpreter.  If any soft keywords are defined to only be
     active when particular *note __future__: 0. statements are in
     effect, these will be included as well.

     Added in version 3.9.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/keyword.py


File: python.info,  Node: tokenize — Tokenizer for Python source,  Next: tabnanny — Detection of ambiguous indentation,  Prev: keyword — Testing for Python keywords,  Up: Python Language Services

5.32.5 ‘tokenize’ — Tokenizer for Python source
-----------------------------------------------

'Source code:' Lib/tokenize.py(1)

__________________________________________________________________

The ‘tokenize’ module provides a lexical scanner for Python source code,
implemented in Python.  The scanner in this module returns comments as
tokens as well, making it useful for implementing “pretty-printers”,
including colorizers for on-screen displays.

To simplify token stream handling, all *note operator: 208b. and *note
delimiter: 208c. tokens and *note Ellipsis: 233f. are returned using the
generic *note OP: 48e0. token type.  The exact type can be determined by
checking the ‘exact_type’ property on the *note named tuple: 651.
returned from *note tokenize.tokenize(): 4dc.

     Warning: Note that the functions in this module are only designed
     to parse syntactically valid Python code (code that does not raise
     when parsed using *note ast.parse(): 1a8.).  The behavior of the
     functions in this module is 'undefined' when providing invalid
     Python code and it can change at any point.

* Menu:

* Tokenizing Input::
* Command-Line Usage: Command-Line Usage<6>.
* Examples: Examples<35>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tokenize.py


File: python.info,  Node: Tokenizing Input,  Next: Command-Line Usage<6>,  Up: tokenize — Tokenizer for Python source

5.32.5.1 Tokenizing Input
.........................

The primary entry point is a *note generator: 109f.:

 -- Function: tokenize.tokenize (readline)

     The ‘tokenize()’ generator requires one argument, 'readline', which
     must be a callable object which provides the same interface as the
     *note io.IOBase.readline(): 1373. method of file objects.  Each
     call to the function should return one line of input as bytes.

     The generator produces 5-tuples with these members: the token type;
     the token string; a 2-tuple ‘(srow, scol)’ of ints specifying the
     row and column where the token begins in the source; a 2-tuple
     ‘(erow, ecol)’ of ints specifying the row and column where the
     token ends in the source; and the line on which the token was
     found.  The line passed (the last tuple item) is the 'physical'
     line.  The 5 tuple is returned as a *note named tuple: 651. with
     the field names: ‘type string start end line’.

     The returned *note named tuple: 651. has an additional property
     named ‘exact_type’ that contains the exact operator type for *note
     OP: 48e0. tokens.  For all other token types ‘exact_type’ equals
     the named tuple ‘type’ field.

     Changed in version 3.1: Added support for named tuples.

     Changed in version 3.3: Added support for ‘exact_type’.

     ‘tokenize()’ determines the source encoding of the file by looking
     for a UTF-8 BOM or encoding cookie, according to PEP 263(1).

 -- Function: tokenize.generate_tokens (readline)

     Tokenize a source reading unicode strings instead of bytes.

     Like *note tokenize(): 4dc, the 'readline' argument is a callable
     returning a single line of input.  However, ‘generate_tokens()’
     expects 'readline' to return a str object rather than bytes.

     The result is an iterator yielding named tuples, exactly like *note
     tokenize(): 4dc.  It does not yield an *note ENCODING: 48f6. token.

All constants from the *note token: fa. module are also exported from
‘tokenize’.

Another function is provided to reverse the tokenization process.  This
is useful for creating tools that tokenize a script, modify the token
stream, and write back the modified script.

 -- Function: tokenize.untokenize (iterable)

     Converts tokens back into Python source code.  The 'iterable' must
     return sequences with at least two elements, the token type and the
     token string.  Any additional sequence elements are ignored.

     The result is guaranteed to tokenize back to match the input so
     that the conversion is lossless and round-trips are assured.  The
     guarantee applies only to the token type and token string as the
     spacing between tokens (column positions) may change.

     It returns bytes, encoded using the *note ENCODING: 48f6. token,
     which is the first token sequence output by *note tokenize(): 4dc.
     If there is no encoding token in the input, it returns a str
     instead.

*note tokenize(): 4dc. needs to detect the encoding of source files it
tokenizes.  The function it uses to do this is available:

 -- Function: tokenize.detect_encoding (readline)

     The ‘detect_encoding()’ function is used to detect the encoding
     that should be used to decode a Python source file.  It requires
     one argument, readline, in the same way as the *note tokenize():
     4dc. generator.

     It will call readline a maximum of twice, and return the encoding
     used (as a string) and a list of any lines (not decoded from bytes)
     it has read in.

     It detects the encoding from the presence of a UTF-8 BOM or an
     encoding cookie as specified in PEP 263(2).  If both a BOM and a
     cookie are present, but disagree, a *note SyntaxError: 18d. will be
     raised.  Note that if the BOM is found, ‘'utf-8-sig'’ will be
     returned as an encoding.

     If no encoding is specified, then the default of ‘'utf-8'’ will be
     returned.

     Use *note open(): 2a34. to open Python source files: it uses
     ‘detect_encoding()’ to detect the file encoding.

 -- Function: tokenize.open (filename)

     Open a file in read only mode using the encoding detected by *note
     detect_encoding(): 2a35.

     Added in version 3.2.

 -- Exception: tokenize.TokenError

     Raised when either a docstring or expression that may be split over
     several lines is not completed anywhere in the file, for example:

          """Beginning of
          docstring

     or:

          [1,
           2,
           3

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0263/

   (2) https://peps.python.org/pep-0263/


File: python.info,  Node: Command-Line Usage<6>,  Next: Examples<35>,  Prev: Tokenizing Input,  Up: tokenize — Tokenizer for Python source

5.32.5.2 Command-Line Usage
...........................

Added in version 3.3.

The ‘tokenize’ module can be executed as a script from the command line.
It is as simple as:

     python -m tokenize [-e] [filename.py]

The following options are accepted:

 -- Option: -h, --help

     show this help message and exit

 -- Option: -e, --exact

     display token names using the exact type

If ‘filename.py’ is specified its contents are tokenized to stdout.
Otherwise, tokenization is performed on stdin.


File: python.info,  Node: Examples<35>,  Prev: Command-Line Usage<6>,  Up: tokenize — Tokenizer for Python source

5.32.5.3 Examples
.................

Example of a script rewriter that transforms float literals into Decimal
objects:

     from tokenize import tokenize, untokenize, NUMBER, STRING, NAME, OP
     from io import BytesIO

     def decistmt(s):
         """Substitute Decimals for floats in a string of statements.

         >>> from decimal import Decimal
         >>> s = 'print(+21.3e-5*-.1234/81.7)'
         >>> decistmt(s)
         "print (+Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7'))"

         The format of the exponent is inherited from the platform C library.
         Known cases are "e-007" (Windows) and "e-07" (not Windows).  Since
         we're only showing 12 digits, and the 13th isn't close to 5, the
         rest of the output should be platform-independent.

         >>> exec(s)  #doctest: +ELLIPSIS
         -3.21716034272e-0...7

         Output from calculations with Decimal should be identical across all
         platforms.

         >>> exec(decistmt(s))
         -3.217160342717258261933904529E-7
         """
         result = []
         g = tokenize(BytesIO(s.encode('utf-8')).readline)  # tokenize the string
         for toknum, tokval, _, _, _ in g:
             if toknum == NUMBER and '.' in tokval:  # replace NUMBER tokens
                 result.extend([
                     (NAME, 'Decimal'),
                     (OP, '('),
                     (STRING, repr(tokval)),
                     (OP, ')')
                 ])
             else:
                 result.append((toknum, tokval))
         return untokenize(result).decode('utf-8')

Example of tokenizing from the command line.  The script:

     def say_hello():
         print("Hello, World!")

     say_hello()

will be tokenized to the following output where the first column is the
range of the line/column coordinates where the token is found, the
second column is the name of the token, and the final column is the
value of the token (if any)

     $ python -m tokenize hello.py
     0,0-0,0:            ENCODING       'utf-8'
     1,0-1,3:            NAME           'def'
     1,4-1,13:           NAME           'say_hello'
     1,13-1,14:          OP             '('
     1,14-1,15:          OP             ')'
     1,15-1,16:          OP             ':'
     1,16-1,17:          NEWLINE        '\n'
     2,0-2,4:            INDENT         '    '
     2,4-2,9:            NAME           'print'
     2,9-2,10:           OP             '('
     2,10-2,25:          STRING         '"Hello, World!"'
     2,25-2,26:          OP             ')'
     2,26-2,27:          NEWLINE        '\n'
     3,0-3,1:            NL             '\n'
     4,0-4,0:            DEDENT         ''
     4,0-4,9:            NAME           'say_hello'
     4,9-4,10:           OP             '('
     4,10-4,11:          OP             ')'
     4,11-4,12:          NEWLINE        '\n'
     5,0-5,0:            ENDMARKER      ''

The exact token type names can be displayed using the *note -e: 4934.
option:

     $ python -m tokenize -e hello.py
     0,0-0,0:            ENCODING       'utf-8'
     1,0-1,3:            NAME           'def'
     1,4-1,13:           NAME           'say_hello'
     1,13-1,14:          LPAR           '('
     1,14-1,15:          RPAR           ')'
     1,15-1,16:          COLON          ':'
     1,16-1,17:          NEWLINE        '\n'
     2,0-2,4:            INDENT         '    '
     2,4-2,9:            NAME           'print'
     2,9-2,10:           LPAR           '('
     2,10-2,25:          STRING         '"Hello, World!"'
     2,25-2,26:          RPAR           ')'
     2,26-2,27:          NEWLINE        '\n'
     3,0-3,1:            NL             '\n'
     4,0-4,0:            DEDENT         ''
     4,0-4,9:            NAME           'say_hello'
     4,9-4,10:           LPAR           '('
     4,10-4,11:          RPAR           ')'
     4,11-4,12:          NEWLINE        '\n'
     5,0-5,0:            ENDMARKER      ''

Example of tokenizing a file programmatically, reading unicode strings
instead of bytes with *note generate_tokens(): 4dd.:

     import tokenize

     with tokenize.open('hello.py') as f:
         tokens = tokenize.generate_tokens(f.readline)
         for token in tokens:
             print(token)

Or reading bytes directly with *note tokenize(): 4dc.:

     import tokenize

     with open('hello.py', 'rb') as f:
         tokens = tokenize.tokenize(f.readline)
         for token in tokens:
             print(token)


File: python.info,  Node: tabnanny — Detection of ambiguous indentation,  Next: pyclbr — Python module browser support,  Prev: tokenize — Tokenizer for Python source,  Up: Python Language Services

5.32.6 ‘tabnanny’ — Detection of ambiguous indentation
------------------------------------------------------

'Source code:' Lib/tabnanny.py(1)

__________________________________________________________________

For the time being this module is intended to be called as a script.
However it is possible to import it into an IDE and use the function
*note check(): 493a. described below.

     Note: The API provided by this module is likely to change in future
     releases; such changes may not be backward compatible.

 -- Function: tabnanny.check (file_or_dir)

     If 'file_or_dir' is a directory and not a symbolic link, then
     recursively descend the directory tree named by 'file_or_dir',
     checking all ‘.py’ files along the way.  If 'file_or_dir' is an
     ordinary Python source file, it is checked for whitespace related
     problems.  The diagnostic messages are written to standard output
     using the *note print(): fae. function.

 -- Data: tabnanny.verbose

     Flag indicating whether to print verbose messages.  This is
     incremented by the ‘-v’ option if called as a script.

 -- Data: tabnanny.filename_only

     Flag indicating whether to print only the filenames of files
     containing whitespace related problems.  This is set to true by the
     ‘-q’ option if called as a script.

 -- Exception: tabnanny.NannyNag

     Raised by *note process_tokens(): 493e. if detecting an ambiguous
     indent.  Captured and handled in *note check(): 493a.

 -- Function: tabnanny.process_tokens (tokens)

     This function is used by *note check(): 493a. to process tokens
     generated by the *note tokenize: fb. module.

See also
........

Module *note tokenize: fb.

     Lexical scanner for Python source code.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tabnanny.py


File: python.info,  Node: pyclbr — Python module browser support,  Next: py_compile — Compile Python source files,  Prev: tabnanny — Detection of ambiguous indentation,  Up: Python Language Services

5.32.7 ‘pyclbr’ — Python module browser support
-----------------------------------------------

'Source code:' Lib/pyclbr.py(1)

__________________________________________________________________

The ‘pyclbr’ module provides limited information about the functions,
classes, and methods defined in a Python-coded module.  The information
is sufficient to implement a module browser.  The information is
extracted from the Python source code rather than by importing the
module, so this module is safe to use with untrusted code.  This
restriction makes it impossible to use this module with modules not
implemented in Python, including all standard and optional extension
modules.

 -- Function: pyclbr.readmodule (module, path=None)

     Return a dictionary mapping module-level class names to class
     descriptors.  If possible, descriptors for imported base classes
     are included.  Parameter 'module' is a string with the name of the
     module to read; it may be the name of a module within a package.
     If given, 'path' is a sequence of directory paths prepended to
     ‘sys.path’, which is used to locate the module source code.

     This function is the original interface and is only kept for back
     compatibility.  It returns a filtered version of the following.

 -- Function: pyclbr.readmodule_ex (module, path=None)

     Return a dictionary-based tree containing a function or class
     descriptors for each function and class defined in the module with
     a ‘def’ or ‘class’ statement.  The returned dictionary maps
     module-level function and class names to their descriptors.  Nested
     objects are entered into the children dictionary of their parent.
     As with readmodule, 'module' names the module to be read and 'path'
     is prepended to sys.path.  If the module being read is a package,
     the returned dictionary has a key ‘'__path__'’ whose value is a
     list containing the package search path.

Added in version 3.7: Descriptors for nested definitions.  They are
accessed through the new children attribute.  Each has a new parent
attribute.

The descriptors returned by these functions are instances of Function
and Class classes.  Users are not expected to create instances of these
classes.

* Menu:

* Function Objects::
* Class Objects: Class Objects<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pyclbr.py


File: python.info,  Node: Function Objects,  Next: Class Objects<2>,  Up: pyclbr — Python module browser support

5.32.7.1 Function Objects
.........................

 -- Class: pyclbr.Function

     Class ‘Function’ instances describe functions defined by def
     statements.  They have the following attributes:

      -- Attribute: file

          Name of the file in which the function is defined.

      -- Attribute: module

          The name of the module defining the function described.

      -- Attribute: name

          The name of the function.

      -- Attribute: lineno

          The line number in the file where the definition starts.

      -- Attribute: parent

          For top-level functions, ‘None’.  For nested functions, the
          parent.

          Added in version 3.7.

      -- Attribute: children

          A *note dictionary: 256. mapping names to descriptors for
          nested functions and classes.

          Added in version 3.7.

      -- Attribute: is_async

          ‘True’ for functions that are defined with the *note async:
          5d4. prefix, ‘False’ otherwise.

          Added in version 3.10.


File: python.info,  Node: Class Objects<2>,  Prev: Function Objects,  Up: pyclbr — Python module browser support

5.32.7.2 Class Objects
......................

 -- Class: pyclbr.Class

     Class ‘Class’ instances describe classes defined by class
     statements.  They have the same attributes as *note Functions:
     4944. and two more.

      -- Attribute: file

          Name of the file in which the class is defined.

      -- Attribute: module

          The name of the module defining the class described.

      -- Attribute: name

          The name of the class.

      -- Attribute: lineno

          The line number in the file where the definition starts.

      -- Attribute: parent

          For top-level classes, ‘None’.  For nested classes, the
          parent.

          Added in version 3.7.

      -- Attribute: children

          A dictionary mapping names to descriptors for nested functions
          and classes.

          Added in version 3.7.

      -- Attribute: super

          A list of ‘Class’ objects which describe the immediate base
          classes of the class being described.  Classes which are named
          as superclasses but which are not discoverable by *note
          readmodule_ex(): 832. are listed as a string with the class
          name instead of as ‘Class’ objects.

      -- Attribute: methods

          A *note dictionary: 256. mapping method names to line numbers.
          This can be derived from the newer *note children: 4954.
          dictionary, but remains for back-compatibility.


File: python.info,  Node: py_compile — Compile Python source files,  Next: compileall — Byte-compile Python libraries,  Prev: pyclbr — Python module browser support,  Up: Python Language Services

5.32.8 ‘py_compile’ — Compile Python source files
-------------------------------------------------

'Source code:' Lib/py_compile.py(1)

__________________________________________________________________

The ‘py_compile’ module provides a function to generate a byte-code file
from a source file, and another function used when the module source
file is invoked as a script.

Though not often needed, this function can be useful when installing
modules for shared use, especially if some of the users may not have
permission to write the byte-code cache files in the directory
containing the source code.

 -- Exception: py_compile.PyCompileError

     Exception raised when an error occurs while attempting to compile
     the file.

 -- Function: py_compile.compile (file, cfile=None, dfile=None,
          doraise=False, optimize=-1,
          invalidation_mode=PycInvalidationMode.TIMESTAMP, quiet=0)

     Compile a source file to byte-code and write out the byte-code
     cache file.  The source code is loaded from the file named 'file'.
     The byte-code is written to 'cfile', which defaults to the PEP
     3147(2)/ PEP 488(3) path, ending in ‘.pyc’.  For example, if 'file'
     is ‘/foo/bar/baz.py’ 'cfile' will default to
     ‘/foo/bar/__pycache__/baz.cpython-32.pyc’ for Python 3.2.  If
     'dfile' is specified, it is used instead of 'file' as the name of
     the source file from which source lines are obtained for display in
     exception tracebacks.  If 'doraise' is true, a *note
     PyCompileError: 495a. is raised when an error is encountered while
     compiling 'file'.  If 'doraise' is false (the default), an error
     string is written to ‘sys.stderr’, but no exception is raised.
     This function returns the path to byte-compiled file, i.e.
     whatever 'cfile' value was used.

     The 'doraise' and 'quiet' arguments determine how errors are
     handled while compiling file.  If 'quiet' is 0 or 1, and 'doraise'
     is false, the default behaviour is enabled: an error string is
     written to ‘sys.stderr’, and the function returns ‘None’ instead of
     a path.  If 'doraise' is true, a *note PyCompileError: 495a. is
     raised instead.  However if 'quiet' is 2, no message is written,
     and 'doraise' has no effect.

     If the path that 'cfile' becomes (either explicitly specified or
     computed) is a symlink or non-regular file, *note FileExistsError:
     105b. will be raised.  This is to act as a warning that import will
     turn those paths into regular files if it is allowed to write
     byte-compiled files to those paths.  This is a side-effect of
     import using file renaming to place the final byte-compiled file
     into place to prevent concurrent file writing issues.

     'optimize' controls the optimization level and is passed to the
     built-in ‘compile()’ function.  The default of ‘-1’ selects the
     optimization level of the current interpreter.

     'invalidation_mode' should be a member of the *note
     PycInvalidationMode: 495b. enum and controls how the generated
     bytecode cache is invalidated at runtime.  The default is *note
     PycInvalidationMode.CHECKED_HASH: 495c. if the ‘SOURCE_DATE_EPOCH’
     environment variable is set, otherwise the default is *note
     PycInvalidationMode.TIMESTAMP: 495d.

     Changed in version 3.2: Changed default value of 'cfile' to be PEP
     3147(4)-compliant.  Previous default was 'file' + ‘'c'’ (‘'o'’ if
     optimization was enabled).  Also added the 'optimize' parameter.

     Changed in version 3.4: Changed code to use *note importlib: 77.
     for the byte-code cache file writing.  This means file
     creation/writing semantics now match what ‘importlib’ does, e.g.
     permissions, write-and-move semantics, etc.  Also added the caveat
     that *note FileExistsError: 105b. is raised if 'cfile' is a symlink
     or non-regular file.

     Changed in version 3.7: The 'invalidation_mode' parameter was added
     as specified in PEP 552(5).  If the ‘SOURCE_DATE_EPOCH’ environment
     variable is set, 'invalidation_mode' will be forced to *note
     PycInvalidationMode.CHECKED_HASH: 495c.

     Changed in version 3.7.2: The ‘SOURCE_DATE_EPOCH’ environment
     variable no longer overrides the value of the 'invalidation_mode'
     argument, and determines its default value instead.

     Changed in version 3.8: The 'quiet' parameter was added.

 -- Class: py_compile.PycInvalidationMode

     An enumeration of possible methods the interpreter can use to
     determine whether a bytecode file is up to date with a source file.
     The ‘.pyc’ file indicates the desired invalidation mode in its
     header.  See *note Cached bytecode invalidation: 5ef. for more
     information on how Python invalidates ‘.pyc’ files at runtime.

     Added in version 3.7.

      -- Attribute: TIMESTAMP

          The ‘.pyc’ file includes the timestamp and size of the source
          file, which Python will compare against the metadata of the
          source file at runtime to determine if the ‘.pyc’ file needs
          to be regenerated.

      -- Attribute: CHECKED_HASH

          The ‘.pyc’ file includes a hash of the source file content,
          which Python will compare against the source at runtime to
          determine if the ‘.pyc’ file needs to be regenerated.

      -- Attribute: UNCHECKED_HASH

          Like *note CHECKED_HASH: 495c, the ‘.pyc’ file includes a hash
          of the source file content.  However, Python will at runtime
          assume the ‘.pyc’ file is up to date and not validate the
          ‘.pyc’ against the source file at all.

          This option is useful when the ‘.pycs’ are kept up to date by
          some system external to Python like a build system.

* Menu:

* Command-Line Interface: Command-Line Interface<5>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/py_compile.py

   (2) https://peps.python.org/pep-3147/

   (3) https://peps.python.org/pep-0488/

   (4) https://peps.python.org/pep-3147/

   (5) https://peps.python.org/pep-0552/


File: python.info,  Node: Command-Line Interface<5>,  Up: py_compile — Compile Python source files

5.32.8.1 Command-Line Interface
...............................

This module can be invoked as a script to compile several source files.
The files named in 'filenames' are compiled and the resulting bytecode
is cached in the normal manner.  This program does not search a
directory structure to locate source files; it only compiles files named
explicitly.  The exit status is nonzero if one of the files could not be
compiled.

 -- Option: <file> ... <fileN>
 -- Option: -

     Positional arguments are files to compile.  If ‘-’ is the only
     parameter, the list of files is taken from standard input.

 -- Option: -q, --quiet

     Suppress errors output.

Changed in version 3.2: Added support for ‘-’.

Changed in version 3.10: Added support for *note -q: 4963.

See also
........

Module *note compileall: 20.

     Utilities to compile all Python source files in a directory tree.


File: python.info,  Node: compileall — Byte-compile Python libraries,  Next: dis — Disassembler for Python bytecode,  Prev: py_compile — Compile Python source files,  Up: Python Language Services

5.32.9 ‘compileall’ — Byte-compile Python libraries
---------------------------------------------------

'Source code:' Lib/compileall.py(1)

__________________________________________________________________

This module provides some utility functions to support installing Python
libraries.  These functions compile Python source files in a directory
tree.  This module can be used to create the cached byte-code files at
library installation time, which makes them available for use even by
users who don’t have write permission to the library directories.

*note Availability: 1ef7.: not WASI.

This module does not work or is not available on WebAssembly.  See *note
WebAssembly platforms: 1910. for more information.

* Menu:

* Command-line use::
* Public functions::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/compileall.py


File: python.info,  Node: Command-line use,  Next: Public functions,  Up: compileall — Byte-compile Python libraries

5.32.9.1 Command-line use
.........................

This module can work as a script (using ‘python -m compileall’) to
compile Python sources.

 -- Option: directory ...
 -- Option: file ...

     Positional arguments are files to compile or directories that
     contain source files, traversed recursively.  If no argument is
     given, behave as if the command line was ‘-l <DIRECTORIES FROM
     SYS.PATH>’.

 -- Option: -l

     Do not recurse into subdirectories, only compile source code files
     directly contained in the named or implied directories.

 -- Option: -f

     Force rebuild even if timestamps are up-to-date.

 -- Option: -q

     Do not print the list of files compiled.  If passed once, error
     messages will still be printed.  If passed twice (‘-qq’), all
     output is suppressed.

 -- Option: -d destdir

     Directory prepended to the path to each file being compiled.  This
     will appear in compilation time tracebacks, and is also compiled in
     to the byte-code file, where it will be used in tracebacks and
     other messages in cases where the source file does not exist at the
     time the byte-code file is executed.

 -- Option: -s strip_prefix

     Remove the given prefix from paths recorded in the ‘.pyc’ files.
     Paths are made relative to the prefix.

     This option can be used with ‘-p’ but not with ‘-d’.

 -- Option: -p prepend_prefix

     Prepend the given prefix to paths recorded in the ‘.pyc’ files.
     Use ‘-p /’ to make the paths absolute.

     This option can be used with ‘-s’ but not with ‘-d’.

 -- Option: -x regex

     regex is used to search the full path to each file considered for
     compilation, and if the regex produces a match, the file is
     skipped.

 -- Option: -i list

     Read the file ‘list’ and add each line that it contains to the list
     of files and directories to compile.  If ‘list’ is ‘-’, read lines
     from ‘stdin’.

 -- Option: -b

     Write the byte-code files to their legacy locations and names,
     which may overwrite byte-code files created by another version of
     Python.  The default is to write files to their PEP 3147(1)
     locations and names, which allows byte-code files from multiple
     versions of Python to coexist.

 -- Option: -r

     Control the maximum recursion level for subdirectories.  If this is
     given, then ‘-l’ option will not be taken into account.  ‘python -m
     compileall <directory> -r 0’ is equivalent to ‘python -m compileall
     <directory> -l’.

 -- Option: -j N

     Use 'N' workers to compile the files within the given directory.
     If ‘0’ is used, then the result of *note os.process_cpu_count():
     1c4. will be used.

 -- Option: --invalidation-mode [timestamp|checked-hash|unchecked-hash]

     Control how the generated byte-code files are invalidated at
     runtime.  The ‘timestamp’ value, means that ‘.pyc’ files with the
     source timestamp and size embedded will be generated.  The
     ‘checked-hash’ and ‘unchecked-hash’ values cause hash-based pycs to
     be generated.  Hash-based pycs embed a hash of the source file
     contents rather than a timestamp.  See *note Cached bytecode
     invalidation: 5ef. for more information on how Python validates
     bytecode cache files at runtime.  The default is ‘timestamp’ if the
     ‘SOURCE_DATE_EPOCH’ environment variable is not set, and
     ‘checked-hash’ if the ‘SOURCE_DATE_EPOCH’ environment variable is
     set.

 -- Option: -o level

     Compile with the given optimization level.  May be used multiple
     times to compile for multiple levels at a time (for example,
     ‘compileall -o 1 -o 2’).

 -- Option: -e dir

     Ignore symlinks pointing outside the given directory.

 -- Option: --hardlink-dupes

     If two ‘.pyc’ files with different optimization level have the same
     content, use hard links to consolidate duplicate files.

Changed in version 3.2: Added the ‘-i’, ‘-b’ and ‘-h’ options.

Changed in version 3.5: Added the ‘-j’, ‘-r’, and ‘-qq’ options.  ‘-q’
option was changed to a multilevel value.  ‘-b’ will always produce a
byte-code file ending in ‘.pyc’, never ‘.pyo’.

Changed in version 3.7: Added the ‘--invalidation-mode’ option.

Changed in version 3.9: Added the ‘-s’, ‘-p’, ‘-e’ and
‘--hardlink-dupes’ options.  Raised the default recursion limit from 10
to *note sys.getrecursionlimit(): 4c7.  Added the possibility to specify
the ‘-o’ option multiple times.

There is no command-line option to control the optimization level used
by the *note compile(): 192. function, because the Python interpreter
itself already provides the option: ‘python -O -m compileall’.

Similarly, the *note compile(): 192. function respects the *note
sys.pycache_prefix: 9af. setting.  The generated bytecode cache will
only be useful if ‘compile()’ is run with the same ‘sys.pycache_prefix’
(if any) that will be used at runtime.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: Public functions,  Prev: Command-line use,  Up: compileall — Byte-compile Python libraries

5.32.9.2 Public functions
.........................

 -- Function: compileall.compile_dir (dir,
          maxlevels=sys.getrecursionlimit(), ddir=None, force=False,
          rx=None, quiet=0, legacy=False, optimize=-1, workers=1,
          invalidation_mode=None, *, stripdir=None, prependdir=None,
          limit_sl_dest=None, hardlink_dupes=False)

     Recursively descend the directory tree named by 'dir', compiling
     all ‘.py’ files along the way.  Return a true value if all the
     files compiled successfully, and a false value otherwise.

     The 'maxlevels' parameter is used to limit the depth of the
     recursion; it defaults to ‘sys.getrecursionlimit()’.

     If 'ddir' is given, it is prepended to the path to each file being
     compiled for use in compilation time tracebacks, and is also
     compiled in to the byte-code file, where it will be used in
     tracebacks and other messages in cases where the source file does
     not exist at the time the byte-code file is executed.

     If 'force' is true, modules are re-compiled even if the timestamps
     are up to date.

     If 'rx' is given, its ‘search’ method is called on the complete
     path to each file considered for compilation, and if it returns a
     true value, the file is skipped.  This can be used to exclude files
     matching a regular expression, given as a *note re.Pattern: fc0.
     object.

     If 'quiet' is ‘False’ or ‘0’ (the default), the filenames and other
     information are printed to standard out.  Set to ‘1’, only errors
     are printed.  Set to ‘2’, all output is suppressed.

     If 'legacy' is true, byte-code files are written to their legacy
     locations and names, which may overwrite byte-code files created by
     another version of Python.  The default is to write files to their
     PEP 3147(1) locations and names, which allows byte-code files from
     multiple versions of Python to coexist.

     'optimize' specifies the optimization level for the compiler.  It
     is passed to the built-in *note compile(): 192. function.  Accepts
     also a sequence of optimization levels which lead to multiple
     compilations of one ‘.py’ file in one call.

     The argument 'workers' specifies how many workers are used to
     compile files in parallel.  The default is to not use multiple
     workers.  If the platform can’t use multiple workers and 'workers'
     argument is given, then sequential compilation will be used as a
     fallback.  If 'workers' is 0, the number of cores in the system is
     used.  If 'workers' is lower than ‘0’, a *note ValueError: 202.
     will be raised.

     'invalidation_mode' should be a member of the *note
     py_compile.PycInvalidationMode: 495b. enum and controls how the
     generated pycs are invalidated at runtime.

     The 'stripdir', 'prependdir' and 'limit_sl_dest' arguments
     correspond to the ‘-s’, ‘-p’ and ‘-e’ options described above.
     They may be specified as ‘str’ or *note os.PathLike: c72.

     If 'hardlink_dupes' is true and two ‘.pyc’ files with different
     optimization level have the same content, use hard links to
     consolidate duplicate files.

     Changed in version 3.2: Added the 'legacy' and 'optimize'
     parameter.

     Changed in version 3.5: Added the 'workers' parameter.

     Changed in version 3.5: 'quiet' parameter was changed to a
     multilevel value.

     Changed in version 3.5: The 'legacy' parameter only writes out
     ‘.pyc’ files, not ‘.pyo’ files no matter what the value of
     'optimize' is.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

     Changed in version 3.7: The 'invalidation_mode' parameter was
     added.

     Changed in version 3.7.2: The 'invalidation_mode' parameter’s
     default value is updated to ‘None’.

     Changed in version 3.8: Setting 'workers' to 0 now chooses the
     optimal number of cores.

     Changed in version 3.9: Added 'stripdir', 'prependdir',
     'limit_sl_dest' and 'hardlink_dupes' arguments.  Default value of
     'maxlevels' was changed from ‘10’ to ‘sys.getrecursionlimit()’

 -- Function: compileall.compile_file (fullname, ddir=None, force=False,
          rx=None, quiet=0, legacy=False, optimize=-1,
          invalidation_mode=None, *, stripdir=None, prependdir=None,
          limit_sl_dest=None, hardlink_dupes=False)

     Compile the file with path 'fullname'.  Return a true value if the
     file compiled successfully, and a false value otherwise.

     If 'ddir' is given, it is prepended to the path to the file being
     compiled for use in compilation time tracebacks, and is also
     compiled in to the byte-code file, where it will be used in
     tracebacks and other messages in cases where the source file does
     not exist at the time the byte-code file is executed.

     If 'rx' is given, its ‘search’ method is passed the full path name
     to the file being compiled, and if it returns a true value, the
     file is not compiled and ‘True’ is returned.  This can be used to
     exclude files matching a regular expression, given as a *note
     re.Pattern: fc0. object.

     If 'quiet' is ‘False’ or ‘0’ (the default), the filenames and other
     information are printed to standard out.  Set to ‘1’, only errors
     are printed.  Set to ‘2’, all output is suppressed.

     If 'legacy' is true, byte-code files are written to their legacy
     locations and names, which may overwrite byte-code files created by
     another version of Python.  The default is to write files to their
     PEP 3147(2) locations and names, which allows byte-code files from
     multiple versions of Python to coexist.

     'optimize' specifies the optimization level for the compiler.  It
     is passed to the built-in *note compile(): 192. function.  Accepts
     also a sequence of optimization levels which lead to multiple
     compilations of one ‘.py’ file in one call.

     'invalidation_mode' should be a member of the *note
     py_compile.PycInvalidationMode: 495b. enum and controls how the
     generated pycs are invalidated at runtime.

     The 'stripdir', 'prependdir' and 'limit_sl_dest' arguments
     correspond to the ‘-s’, ‘-p’ and ‘-e’ options described above.
     They may be specified as ‘str’ or *note os.PathLike: c72.

     If 'hardlink_dupes' is true and two ‘.pyc’ files with different
     optimization level have the same content, use hard links to
     consolidate duplicate files.

     Added in version 3.2.

     Changed in version 3.5: 'quiet' parameter was changed to a
     multilevel value.

     Changed in version 3.5: The 'legacy' parameter only writes out
     ‘.pyc’ files, not ‘.pyo’ files no matter what the value of
     'optimize' is.

     Changed in version 3.7: The 'invalidation_mode' parameter was
     added.

     Changed in version 3.7.2: The 'invalidation_mode' parameter’s
     default value is updated to ‘None’.

     Changed in version 3.9: Added 'stripdir', 'prependdir',
     'limit_sl_dest' and 'hardlink_dupes' arguments.

 -- Function: compileall.compile_path (skip_curdir=True, maxlevels=0,
          force=False, quiet=0, legacy=False, optimize=-1,
          invalidation_mode=None)

     Byte-compile all the ‘.py’ files found along ‘sys.path’.  Return a
     true value if all the files compiled successfully, and a false
     value otherwise.

     If 'skip_curdir' is true (the default), the current directory is
     not included in the search.  All other parameters are passed to the
     *note compile_dir(): b3e. function.  Note that unlike the other
     compile functions, ‘maxlevels’ defaults to ‘0’.

     Changed in version 3.2: Added the 'legacy' and 'optimize'
     parameter.

     Changed in version 3.5: 'quiet' parameter was changed to a
     multilevel value.

     Changed in version 3.5: The 'legacy' parameter only writes out
     ‘.pyc’ files, not ‘.pyo’ files no matter what the value of
     'optimize' is.

     Changed in version 3.7: The 'invalidation_mode' parameter was
     added.

     Changed in version 3.7.2: The 'invalidation_mode' parameter’s
     default value is updated to ‘None’.

To force a recompile of all the ‘.py’ files in the ‘Lib/’ subdirectory
and all its subdirectories:

     import compileall

     compileall.compile_dir('Lib/', force=True)

     # Perform same compilation, excluding files in .svn directories.
     import re
     compileall.compile_dir('Lib/', rx=re.compile(r'[/\\][.]svn'), force=True)

     # pathlib.Path objects can also be used.
     import pathlib
     compileall.compile_dir(pathlib.Path('Lib/'), force=True)

See also
........

Module *note py_compile: b3.

     Byte-compile a single source file.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/

   (2) https://peps.python.org/pep-3147/


File: python.info,  Node: dis — Disassembler for Python bytecode,  Next: pickletools — Tools for pickle developers,  Prev: compileall — Byte-compile Python libraries,  Up: Python Language Services

5.32.10 ‘dis’ — Disassembler for Python bytecode
------------------------------------------------

'Source code:' Lib/dis.py(1)

__________________________________________________________________

The ‘dis’ module supports the analysis of CPython *note bytecode: 187.
by disassembling it.  The CPython bytecode which this module takes as an
input is defined in the file ‘Include/opcode.h’ and used by the compiler
and the interpreter.

'CPython implementation detail:' Bytecode is an implementation detail of
the CPython interpreter.  No guarantees are made that bytecode will not
be added, removed, or changed between versions of Python.  Use of this
module should not be considered to work across Python VMs or Python
releases.

Changed in version 3.6: Use 2 bytes for each instruction.  Previously
the number of bytes varied by instruction.

Changed in version 3.10: The argument of jump, exception handling and
loop instructions is now the instruction offset rather than the byte
offset.

Changed in version 3.11: Some instructions are accompanied by one or
more inline cache entries, which take the form of *note CACHE: 6fc.
instructions.  These instructions are hidden by default, but can be
shown by passing ‘show_caches=True’ to any ‘dis’ utility.  Furthermore,
the interpreter now adapts the bytecode to specialize it for different
runtime conditions.  The adaptive bytecode can be shown by passing
‘adaptive=True’.

Changed in version 3.12: The argument of a jump is the offset of the
target instruction relative to the instruction that appears immediately
after the jump instruction’s *note CACHE: 6fc. entries.

As a consequence, the presence of the *note CACHE: 6fc. instructions is
transparent for forward jumps but needs to be taken into account when
reasoning about backward jumps.

Changed in version 3.13: The output shows logical labels rather than
instruction offsets for jump targets and exception handlers.  The ‘-O’
command line option and the ‘show_offsets’ argument were added.

Example: Given the function ‘myfunc()’:

     def myfunc(alist):
         return len(alist)

the following command can be used to display the disassembly of
‘myfunc()’:

     >>> dis.dis(myfunc)
       2           RESUME                   0

       3           LOAD_GLOBAL              1 (len + NULL)
                   LOAD_FAST                0 (alist)
                   CALL                     1
                   RETURN_VALUE

(The “2” is a line number).

* Menu:

* Command-line interface: Command-line interface<10>.
* Bytecode analysis::
* Analysis functions::
* Python Bytecode Instructions::
* Opcode collections::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/dis.py


File: python.info,  Node: Command-line interface<10>,  Next: Bytecode analysis,  Up: dis — Disassembler for Python bytecode

5.32.10.1 Command-line interface
................................

The ‘dis’ module can be invoked as a script from the command line:

     python -m dis [-h] [-C] [-O] [infile]

The following options are accepted:

 -- Option: -h, --help

     Display usage and exit.

 -- Option: -C, --show-caches

     Show inline caches.

     Added in version 3.13.

 -- Option: -O, --show-offsets

     Show offsets of instructions.

     Added in version 3.13.

If ‘infile’ is specified, its disassembled code will be written to
stdout.  Otherwise, disassembly is performed on compiled source code
received from stdin.


File: python.info,  Node: Bytecode analysis,  Next: Analysis functions,  Prev: Command-line interface<10>,  Up: dis — Disassembler for Python bytecode

5.32.10.2 Bytecode analysis
...........................

Added in version 3.4.

The bytecode analysis API allows pieces of Python code to be wrapped in
a *note Bytecode: f66. object that provides easy access to details of
the compiled code.

 -- Class: dis.Bytecode (x, *, first_line=None, current_offset=None,
          show_caches=False, adaptive=False, show_offsets=False)

     Analyse the bytecode corresponding to a function, generator,
     asynchronous generator, coroutine, method, string of source code,
     or a code object (as returned by *note compile(): 192.).

     This is a convenience wrapper around many of the functions listed
     below, most notably *note get_instructions(): 1d9, as iterating
     over a ‘Bytecode’ instance yields the bytecode operations as *note
     Instruction: 1da. instances.

     If 'first_line' is not ‘None’, it indicates the line number that
     should be reported for the first source line in the disassembled
     code.  Otherwise, the source line information (if any) is taken
     directly from the disassembled code object.

     If 'current_offset' is not ‘None’, it refers to an instruction
     offset in the disassembled code.  Setting this means *note dis():
     f67. will display a “current instruction” marker against the
     specified opcode.

     If 'show_caches' is ‘True’, *note dis(): f67. will display inline
     cache entries used by the interpreter to specialize the bytecode.

     If 'adaptive' is ‘True’, *note dis(): f67. will display specialized
     bytecode that may be different from the original bytecode.

     If 'show_offsets' is ‘True’, *note dis(): f67. will include
     instruction offsets in the output.

      -- Method: classmethod from_traceback (tb, *, show_caches=False)

          Construct a ‘Bytecode’ instance from the given traceback,
          setting 'current_offset' to the instruction responsible for
          the exception.

      -- Data: codeobj

          The compiled code object.

      -- Data: first_line

          The first source line of the code object (if available)

      -- Method: dis ()

          Return a formatted view of the bytecode operations (the same
          as printed by *note dis.dis(): b4c, but returned as a
          multi-line string).

      -- Method: info ()

          Return a formatted multi-line string with detailed information
          about the code object, like *note code_info(): 127f.

     Changed in version 3.7: This can now handle coroutine and
     asynchronous generator objects.

     Changed in version 3.11: Added the 'show_caches' and 'adaptive'
     parameters.

Example:

     >>> bytecode = dis.Bytecode(myfunc)
     >>> for instr in bytecode:
     ...     print(instr.opname)
     ...
     RESUME
     LOAD_GLOBAL
     LOAD_FAST
     CALL
     RETURN_VALUE


File: python.info,  Node: Analysis functions,  Next: Python Bytecode Instructions,  Prev: Bytecode analysis,  Up: dis — Disassembler for Python bytecode

5.32.10.3 Analysis functions
............................

The ‘dis’ module also defines the following analysis functions that
convert the input directly to the desired output.  They can be useful if
only a single operation is being performed, so the intermediate analysis
object isn’t useful:

 -- Function: dis.code_info (x)

     Return a formatted multi-line string with detailed code object
     information for the supplied function, generator, asynchronous
     generator, coroutine, method, source code string or code object.

     Note that the exact contents of code info strings are highly
     implementation dependent and they may change arbitrarily across
     Python VMs or Python releases.

     Added in version 3.2.

     Changed in version 3.7: This can now handle coroutine and
     asynchronous generator objects.

 -- Function: dis.show_code (x, *, file=None)

     Print detailed code object information for the supplied function,
     method, source code string or code object to 'file' (or
     ‘sys.stdout’ if 'file' is not specified).

     This is a convenient shorthand for ‘print(code_info(x),
     file=file)’, intended for interactive exploration at the
     interpreter prompt.

     Added in version 3.2.

     Changed in version 3.4: Added 'file' parameter.

 -- Function: dis.dis (x=None, *, file=None, depth=None,
          show_caches=False, adaptive=False)

     Disassemble the 'x' object.  'x' can denote either a module, a
     class, a method, a function, a generator, an asynchronous
     generator, a coroutine, a code object, a string of source code or a
     byte sequence of raw bytecode.  For a module, it disassembles all
     functions.  For a class, it disassembles all methods (including
     class and static methods).  For a code object or sequence of raw
     bytecode, it prints one line per bytecode instruction.  It also
     recursively disassembles nested code objects.  These can include
     generator expressions, nested functions, the bodies of nested
     classes, and the code objects used for *note annotation scopes:
     188.  Strings are first compiled to code objects with the *note
     compile(): 192. built-in function before being disassembled.  If no
     object is provided, this function disassembles the last traceback.

     The disassembly is written as text to the supplied 'file' argument
     if provided and to ‘sys.stdout’ otherwise.

     The maximal depth of recursion is limited by 'depth' unless it is
     ‘None’.  ‘depth=0’ means no recursion.

     If 'show_caches' is ‘True’, this function will display inline cache
     entries used by the interpreter to specialize the bytecode.

     If 'adaptive' is ‘True’, this function will display specialized
     bytecode that may be different from the original bytecode.

     Changed in version 3.4: Added 'file' parameter.

     Changed in version 3.7: Implemented recursive disassembling and
     added 'depth' parameter.

     Changed in version 3.7: This can now handle coroutine and
     asynchronous generator objects.

     Changed in version 3.11: Added the 'show_caches' and 'adaptive'
     parameters.

 -- Function: dis.distb (tb=None, *, file=None, show_caches=False,
          adaptive=False, show_offset=False)

     Disassemble the top-of-stack function of a traceback, using the
     last traceback if none was passed.  The instruction causing the
     exception is indicated.

     The disassembly is written as text to the supplied 'file' argument
     if provided and to ‘sys.stdout’ otherwise.

     Changed in version 3.4: Added 'file' parameter.

     Changed in version 3.11: Added the 'show_caches' and 'adaptive'
     parameters.

     Changed in version 3.13: Added the 'show_offsets' parameter.

 -- Function: dis.disassemble (code, lasti=-1, *, file=None,
          show_caches=False, adaptive=False)

 -- Function: disco(code, lasti=-1, *, file=None, show_caches=False,
          adaptive=False,

 -- Function: show_offsets=False)

     Disassemble a code object, indicating the last instruction if
     'lasti' was provided.  The output is divided in the following
     columns:

       1. the line number, for the first instruction of each line

       2. the current instruction, indicated as ‘-->’,

       3. a labelled instruction, indicated with ‘>>’,

       4. the address of the instruction,

       5. the operation code name,

       6. operation parameters, and

       7. interpretation of the parameters in parentheses.

     The parameter interpretation recognizes local and global variable
     names, constant values, branch targets, and compare operators.

     The disassembly is written as text to the supplied 'file' argument
     if provided and to ‘sys.stdout’ otherwise.

     Changed in version 3.4: Added 'file' parameter.

     Changed in version 3.11: Added the 'show_caches' and 'adaptive'
     parameters.

     Changed in version 3.13: Added the 'show_offsets' parameter.

 -- Function: dis.get_instructions (x, *, first_line=None,
          show_caches=False, adaptive=False)

     Return an iterator over the instructions in the supplied function,
     method, source code string or code object.

     The iterator generates a series of *note Instruction: 1da. named
     tuples giving the details of each operation in the supplied code.

     If 'first_line' is not ‘None’, it indicates the line number that
     should be reported for the first source line in the disassembled
     code.  Otherwise, the source line information (if any) is taken
     directly from the disassembled code object.

     The 'adaptive' parameter works as it does in *note dis(): 38.

     Added in version 3.4.

     Changed in version 3.11: Added the 'show_caches' and 'adaptive'
     parameters.

     Changed in version 3.13: The 'show_caches' parameter is deprecated
     and has no effect.  The iterator generates the *note Instruction:
     1da. instances with the 'cache_info' field populated (regardless of
     the value of 'show_caches') and it no longer generates separate
     items for the cache entries.

 -- Function: dis.findlinestarts (code)

     This generator function uses the *note co_lines(): 2fb. method of
     the *note code object: 1d2. 'code' to find the offsets which are
     starts of lines in the source code.  They are generated as
     ‘(offset, lineno)’ pairs.

     Changed in version 3.6: Line numbers can be decreasing.  Before,
     they were always increasing.

     Changed in version 3.10: The PEP 626(1) *note co_lines(): 2fb.
     method is used instead of the *note co_firstlineno: 20f7. and *note
     co_lnotab: 2e0. attributes of the *note code object: 1d2.

     Changed in version 3.13: Line numbers can be ‘None’ for bytecode
     that does not map to source lines.

 -- Function: dis.findlabels (code)

     Detect all offsets in the raw compiled bytecode string 'code' which
     are jump targets, and return a list of these offsets.

 -- Function: dis.stack_effect (opcode, oparg=None, *, jump=None)

     Compute the stack effect of 'opcode' with argument 'oparg'.

     If the code has a jump target and 'jump' is ‘True’,
     ‘stack_effect()’ will return the stack effect of jumping.  If
     'jump' is ‘False’, it will return the stack effect of not jumping.
     And if 'jump' is ‘None’ (default), it will return the maximal stack
     effect of both cases.

     Added in version 3.4.

     Changed in version 3.8: Added 'jump' parameter.

     Changed in version 3.13: If ‘oparg’ is omitted (or ‘None’), the
     stack effect is now returned for ‘oparg=0’.  Previously this was an
     error for opcodes that use their arg.  It is also no longer an
     error to pass an integer ‘oparg’ when the ‘opcode’ does not use it;
     the ‘oparg’ in this case is ignored.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0626/


File: python.info,  Node: Python Bytecode Instructions,  Next: Opcode collections,  Prev: Analysis functions,  Up: dis — Disassembler for Python bytecode

5.32.10.4 Python Bytecode Instructions
......................................

The *note get_instructions(): 1d9. function and *note Bytecode: f66.
class provide details of bytecode instructions as *note Instruction:
1da. instances:

 -- Class: dis.Instruction

     Details for a bytecode operation

      -- Data: opcode

          numeric code for operation, corresponding to the opcode values
          listed below and the bytecode values in the *note Opcode
          collections: 498f.

      -- Data: opname

          human readable name for operation

      -- Data: baseopcode

          numeric code for the base operation if operation is
          specialized; otherwise equal to *note opcode: 498e.

      -- Data: baseopname

          human readable name for the base operation if operation is
          specialized; otherwise equal to *note opname: 4993.

      -- Data: arg

          numeric argument to operation (if any), otherwise ‘None’

      -- Data: oparg

          alias for *note arg: 4994.

      -- Data: argval

          resolved arg value (if any), otherwise ‘None’

      -- Data: argrepr

          human readable description of operation argument (if any),
          otherwise an empty string.

      -- Data: offset

          start index of operation within bytecode sequence

      -- Data: start_offset

          start index of operation within bytecode sequence, including
          prefixed ‘EXTENDED_ARG’ operations if present; otherwise equal
          to *note offset: 4998.

      -- Data: cache_offset

          start index of the cache entries following the operation

      -- Data: end_offset

          end index of the cache entries following the operation

      -- Data: starts_line

          ‘True’ if this opcode starts a source line, otherwise ‘False’

      -- Data: line_number

          source line number associated with this opcode (if any),
          otherwise ‘None’

      -- Data: is_jump_target

          ‘True’ if other code jumps to here, otherwise ‘False’

      -- Data: jump_target

          bytecode index of the jump target if this is a jump operation,
          otherwise ‘None’

      -- Data: positions

          *note dis.Positions: 4712. object holding the start and end
          locations that are covered by this instruction.

      -- Data: cache_info

          Information about the cache entries of this instruction, as
          triplets of the form ‘(name, size, data)’, where the ‘name’
          and ‘size’ describe the cache format and data is the contents
          of the cache.  ‘cache_info’ is ‘None’ if the instruction does
          not have caches.

     Added in version 3.4.

     Changed in version 3.11: Field ‘positions’ is added.

     Changed in version 3.13: Changed field ‘starts_line’.

     Added fields ‘start_offset’, ‘cache_offset’, ‘end_offset’,
     ‘baseopname’, ‘baseopcode’, ‘jump_target’, ‘oparg’, ‘line_number’
     and ‘cache_info’.

 -- Class: dis.Positions

     In case the information is not available, some fields might be
     ‘None’.

      -- Data: lineno

      -- Data: end_lineno

      -- Data: col_offset

      -- Data: end_col_offset

     Added in version 3.11.

The Python compiler currently generates the following bytecode
instructions.

'General instructions'

In the following, We will refer to the interpreter stack as ‘STACK’ and
describe operations on it as if it was a Python list.  The top of the
stack corresponds to ‘STACK[-1]’ in this language.

 -- Opcode: NOP

     Do nothing code.  Used as a placeholder by the bytecode optimizer,
     and to generate line tracing events.

 -- Opcode: POP_TOP

     Removes the top-of-stack item:

          STACK.pop()

 -- Opcode: END_FOR

     Removes the top-of-stack item.  Equivalent to ‘POP_TOP’.  Used to
     clean up at the end of loops, hence the name.

     Added in version 3.12.

 -- Opcode: END_SEND

     Implements ‘del STACK[-2]’.  Used to clean up when a generator
     exits.

     Added in version 3.12.

 -- Opcode: COPY (i)

     Push the i-th item to the top of the stack without removing it from
     its original location:

          assert i > 0
          STACK.append(STACK[-i])

     Added in version 3.11.

 -- Opcode: SWAP (i)

     Swap the top of the stack with the i-th element:

          STACK[-i], STACK[-1] = STACK[-1], STACK[-i]

     Added in version 3.11.

 -- Opcode: CACHE

     Rather than being an actual instruction, this opcode is used to
     mark extra space for the interpreter to cache useful data directly
     in the bytecode itself.  It is automatically hidden by all ‘dis’
     utilities, but can be viewed with ‘show_caches=True’.

     Logically, this space is part of the preceding instruction.  Many
     opcodes expect to be followed by an exact number of caches, and
     will instruct the interpreter to skip over them at runtime.

     Populated caches can look like arbitrary instructions, so great
     care should be taken when reading or modifying raw, adaptive
     bytecode containing quickened data.

     Added in version 3.11.

'Unary operations'

Unary operations take the top of the stack, apply the operation, and
push the result back on the stack.

 -- Opcode: UNARY_NEGATIVE

     Implements ‘STACK[-1] = -STACK[-1]’.

 -- Opcode: UNARY_NOT

     Implements ‘STACK[-1] = not STACK[-1]’.

     Changed in version 3.13: This instruction now requires an exact
     *note bool: 46b. operand.

 -- Opcode: UNARY_INVERT

     Implements ‘STACK[-1] = ~STACK[-1]’.

 -- Opcode: GET_ITER

     Implements ‘STACK[-1] = iter(STACK[-1])’.

 -- Opcode: GET_YIELD_FROM_ITER

     If ‘STACK[-1]’ is a *note generator iterator: bff. or *note
     coroutine: 494. object it is left as is.  Otherwise, implements
     ‘STACK[-1] = iter(STACK[-1])’.

     Added in version 3.5.

 -- Opcode: TO_BOOL

     Implements ‘STACK[-1] = bool(STACK[-1])’.

     Added in version 3.13.

'Binary and in-place operations'

Binary operations remove the top two items from the stack (‘STACK[-1]’
and ‘STACK[-2]’).  They perform the operation, then put the result back
on the stack.

In-place operations are like binary operations, but the operation is
done in-place when ‘STACK[-2]’ supports it, and the resulting
‘STACK[-1]’ may be (but does not have to be) the original ‘STACK[-2]’.

 -- Opcode: BINARY_OP (op)

     Implements the binary and in-place operators (depending on the
     value of 'op'):

          rhs = STACK.pop()
          lhs = STACK.pop()
          STACK.append(lhs op rhs)

     Added in version 3.11.

 -- Opcode: BINARY_SUBSCR

     Implements:

          key = STACK.pop()
          container = STACK.pop()
          STACK.append(container[key])

 -- Opcode: STORE_SUBSCR

     Implements:

          key = STACK.pop()
          container = STACK.pop()
          value = STACK.pop()
          container[key] = value

 -- Opcode: DELETE_SUBSCR

     Implements:

          key = STACK.pop()
          container = STACK.pop()
          del container[key]

 -- Opcode: BINARY_SLICE

     Implements:

          end = STACK.pop()
          start = STACK.pop()
          container = STACK.pop()
          STACK.append(container[start:end])

     Added in version 3.12.

 -- Opcode: STORE_SLICE

     Implements:

          end = STACK.pop()
          start = STACK.pop()
          container = STACK.pop()
          value = STACK.pop()
          container[start:end] = value

     Added in version 3.12.

'Coroutine opcodes'

 -- Opcode: GET_AWAITABLE (where)

     Implements ‘STACK[-1] = get_awaitable(STACK[-1])’, where
     ‘get_awaitable(o)’ returns ‘o’ if ‘o’ is a coroutine object or a
     generator object with the *note CO_ITERABLE_COROUTINE: 4723. flag,
     or resolves ‘o.__await__’.

          If the ‘where’ operand is nonzero, it indicates where the
          instruction occurs:

             * ‘1’: After a call to ‘__aenter__’

             * ‘2’: After a call to ‘__aexit__’

     Added in version 3.5.

     Changed in version 3.11: Previously, this instruction did not have
     an oparg.

 -- Opcode: GET_AITER

     Implements ‘STACK[-1] = STACK[-1].__aiter__()’.

     Added in version 3.5.

     Changed in version 3.7: Returning awaitable objects from
     ‘__aiter__’ is no longer supported.

 -- Opcode: GET_ANEXT

     Implement ‘STACK.append(get_awaitable(STACK[-1].__anext__()))’ to
     the stack.  See ‘GET_AWAITABLE’ for details about ‘get_awaitable’.

     Added in version 3.5.

 -- Opcode: END_ASYNC_FOR

     Terminates an *note async for: ac0. loop.  Handles an exception
     raised when awaiting a next item.  The stack contains the async
     iterable in ‘STACK[-2]’ and the raised exception in ‘STACK[-1]’.
     Both are popped.  If the exception is not *note StopAsyncIteration:
     1bbe, it is re-raised.

     Added in version 3.8.

     Changed in version 3.11: Exception representation on the stack now
     consist of one, not three, items.

 -- Opcode: CLEANUP_THROW

     Handles an exception raised during a *note throw(): 4fb. or *note
     close(): 15df. call through the current frame.  If ‘STACK[-1]’ is
     an instance of *note StopIteration: c1b, pop three values from the
     stack and push its ‘value’ member.  Otherwise, re-raise
     ‘STACK[-1]’.

     Added in version 3.12.

 -- Opcode: BEFORE_ASYNC_WITH

     Resolves ‘__aenter__’ and ‘__aexit__’ from ‘STACK[-1]’.  Pushes
     ‘__aexit__’ and result of ‘__aenter__()’ to the stack:

          STACK.extend((__aexit__, __aenter__())

     Added in version 3.5.

'Miscellaneous opcodes'

 -- Opcode: SET_ADD (i)

     Implements:

          item = STACK.pop()
          set.add(STACK[-i], item)

     Used to implement set comprehensions.

 -- Opcode: LIST_APPEND (i)

     Implements:

          item = STACK.pop()
          list.append(STACK[-i], item)

     Used to implement list comprehensions.

 -- Opcode: MAP_ADD (i)

     Implements:

          value = STACK.pop()
          key = STACK.pop()
          dict.__setitem__(STACK[-i], key, value)

     Used to implement dict comprehensions.

     Added in version 3.1.

     Changed in version 3.8: Map value is ‘STACK[-1]’ and map key is
     ‘STACK[-2]’.  Before, those were reversed.

For all of the *note SET_ADD: 49b2, *note LIST_APPEND: 49b3. and *note
MAP_ADD: ac1. instructions, while the added value or key/value pair is
popped off, the container object remains on the stack so that it is
available for further iterations of the loop.

 -- Opcode: RETURN_VALUE

     Returns with ‘STACK[-1]’ to the caller of the function.

 -- Opcode: RETURN_CONST (consti)

     Returns with ‘co_consts[consti]’ to the caller of the function.

     Added in version 3.12.

 -- Opcode: YIELD_VALUE

     Yields ‘STACK.pop()’ from a *note generator: 109f.

     Changed in version 3.11: oparg set to be the stack depth.

     Changed in version 3.12: oparg set to be the exception block depth,
     for efficient closing of generators.

     Changed in version 3.13: oparg is ‘1’ if this instruction is part
     of a yield-from or await, and ‘0’ otherwise.

 -- Opcode: SETUP_ANNOTATIONS

     Checks whether ‘__annotations__’ is defined in ‘locals()’, if not
     it is set up to an empty ‘dict’.  This opcode is only emitted if a
     class or module body contains *note variable annotations: d7f.
     statically.

     Added in version 3.6.

 -- Opcode: POP_EXCEPT

     Pops a value from the stack, which is used to restore the exception
     state.

     Changed in version 3.11: Exception representation on the stack now
     consist of one, not three, items.

 -- Opcode: RERAISE

     Re-raises the exception currently on top of the stack.  If oparg is
     non-zero, pops an additional value from the stack which is used to
     set *note f_lasti: 88f. of the current frame.

     Added in version 3.9.

     Changed in version 3.11: Exception representation on the stack now
     consist of one, not three, items.

 -- Opcode: PUSH_EXC_INFO

     Pops a value from the stack.  Pushes the current exception to the
     top of the stack.  Pushes the value originally popped back to the
     stack.  Used in exception handlers.

     Added in version 3.11.

 -- Opcode: CHECK_EXC_MATCH

     Performs exception matching for ‘except’.  Tests whether the
     ‘STACK[-2]’ is an exception matching ‘STACK[-1]’.  Pops ‘STACK[-1]’
     and pushes the boolean result of the test.

     Added in version 3.11.

 -- Opcode: CHECK_EG_MATCH

     Performs exception matching for ‘except*’.  Applies
     ‘split(STACK[-1])’ on the exception group representing ‘STACK[-2]’.

     In case of a match, pops two items from the stack and pushes the
     non-matching subgroup (‘None’ in case of full match) followed by
     the matching subgroup.  When there is no match, pops one item (the
     match type) and pushes ‘None’.

     Added in version 3.11.

 -- Opcode: WITH_EXCEPT_START

     Calls the function in position 4 on the stack with arguments (type,
     val, tb) representing the exception at the top of the stack.  Used
     to implement the call ‘context_manager.__exit__(*exc_info())’ when
     an exception has occurred in a *note with: 5d5. statement.

     Added in version 3.9.

     Changed in version 3.11: The ‘__exit__’ function is in position 4
     of the stack rather than 7.  Exception representation on the stack
     now consist of one, not three, items.

 -- Opcode: LOAD_ASSERTION_ERROR

     Pushes *note AssertionError: 6ac. onto the stack.  Used by the
     *note assert: 972. statement.

     Added in version 3.9.

 -- Opcode: LOAD_BUILD_CLASS

     Pushes ‘builtins.__build_class__()’ onto the stack.  It is later
     called to construct a class.

 -- Opcode: BEFORE_WITH

     This opcode performs several operations before a with block starts.
     First, it loads *note __exit__(): 1349. from the context manager
     and pushes it onto the stack for later use by *note
     WITH_EXCEPT_START: 49b6.  Then, *note __enter__(): 5cb. is called.
     Finally, the result of calling the ‘__enter__()’ method is pushed
     onto the stack.

     Added in version 3.11.

 -- Opcode: GET_LEN

     Perform ‘STACK.append(len(STACK[-1]))’.  Used in *note match: 813.
     statements where comparison with structure of pattern is needed.

     Added in version 3.10.

 -- Opcode: MATCH_MAPPING

     If ‘STACK[-1]’ is an instance of *note collections.abc.Mapping:
     8d3. (or, more technically: if it has the *note Py_TPFLAGS_MAPPING:
     19fe. flag set in its *note tp_flags: 1a18.), push ‘True’ onto the
     stack.  Otherwise, push ‘False’.

     Added in version 3.10.

 -- Opcode: MATCH_SEQUENCE

     If ‘STACK[-1]’ is an instance of *note collections.abc.Sequence:
     1209. and is 'not' an instance of *note str: 44f./*note bytes:
     1c2./*note bytearray: 2ea. (or, more technically: if it has the
     *note Py_TPFLAGS_SEQUENCE: 19ff. flag set in its *note tp_flags:
     1a18.), push ‘True’ onto the stack.  Otherwise, push ‘False’.

     Added in version 3.10.

 -- Opcode: MATCH_KEYS

     ‘STACK[-1]’ is a tuple of mapping keys, and ‘STACK[-2]’ is the
     match subject.  If ‘STACK[-2]’ contains all of the keys in
     ‘STACK[-1]’, push a *note tuple: 373. containing the corresponding
     values.  Otherwise, push ‘None’.

     Added in version 3.10.

     Changed in version 3.11: Previously, this instruction also pushed a
     boolean value indicating success (‘True’) or failure (‘False’).

 -- Opcode: STORE_NAME (namei)

     Implements ‘name = STACK.pop()’.  'namei' is the index of 'name' in
     the attribute *note co_names: 20f6. of the *note code object: 1d2.
     The compiler tries to use *note STORE_FAST: 1802. or *note
     STORE_GLOBAL: 49bc. if possible.

 -- Opcode: DELETE_NAME (namei)

     Implements ‘del name’, where 'namei' is the index into *note
     co_names: 20f6. attribute of the *note code object: 1d2.

 -- Opcode: UNPACK_SEQUENCE (count)

     Unpacks ‘STACK[-1]’ into 'count' individual values, which are put
     onto the stack right-to-left.  Require there to be exactly 'count'
     values.:

          assert(len(STACK[-1]) == count)
          STACK.extend(STACK.pop()[:-count-1:-1])

 -- Opcode: UNPACK_EX (counts)

     Implements assignment with a starred target: Unpacks an iterable in
     ‘STACK[-1]’ into individual values, where the total number of
     values can be smaller than the number of items in the iterable: one
     of the new values will be a list of all leftover items.

     The number of values before and after the list value is limited to
     255.

     The number of values before the list value is encoded in the
     argument of the opcode.  The number of values after the list if any
     is encoded using an ‘EXTENDED_ARG’.  As a consequence, the argument
     can be seen as a two bytes values where the low byte of 'counts' is
     the number of values before the list value, the high byte of
     'counts' the number of values after it.

     The extracted values are put onto the stack right-to-left, i.e.
     ‘a, *b, c = d’ will be stored after execution as ‘STACK.extend((a,
     b, c))’.

 -- Opcode: STORE_ATTR (namei)

     Implements:

          obj = STACK.pop()
          value = STACK.pop()
          obj.name = value

     where 'namei' is the index of name in *note co_names: 20f6. of the
     *note code object: 1d2.

 -- Opcode: DELETE_ATTR (namei)

     Implements:

          obj = STACK.pop()
          del obj.name

     where 'namei' is the index of name into *note co_names: 20f6. of
     the *note code object: 1d2.

 -- Opcode: STORE_GLOBAL (namei)

     Works as *note STORE_NAME: 49bb, but stores the name as a global.

 -- Opcode: DELETE_GLOBAL (namei)

     Works as *note DELETE_NAME: 49bd, but deletes a global name.

 -- Opcode: LOAD_CONST (consti)

     Pushes ‘co_consts[consti]’ onto the stack.

 -- Opcode: LOAD_NAME (namei)

     Pushes the value associated with ‘co_names[namei]’ onto the stack.
     The name is looked up within the locals, then the globals, then the
     builtins.

 -- Opcode: LOAD_LOCALS

     Pushes a reference to the locals dictionary onto the stack.  This
     is used to prepare namespace dictionaries for *note
     LOAD_FROM_DICT_OR_DEREF: 4e9. and *note LOAD_FROM_DICT_OR_GLOBALS:
     4ea.

     Added in version 3.12.

 -- Opcode: LOAD_FROM_DICT_OR_GLOBALS (i)

     Pops a mapping off the stack and looks up the value for
     ‘co_names[namei]’.  If the name is not found there, looks it up in
     the globals and then the builtins, similar to *note LOAD_GLOBAL:
     17f9.  This is used for loading global variables in *note
     annotation scopes: 188. within class bodies.

     Added in version 3.12.

 -- Opcode: BUILD_TUPLE (count)

     Creates a tuple consuming 'count' items from the stack, and pushes
     the resulting tuple onto the stack:

          if count == 0:
              value = ()
          else:
              value = tuple(STACK[-count:])
              STACK = STACK[:-count]

          STACK.append(value)

 -- Opcode: BUILD_LIST (count)

     Works as *note BUILD_TUPLE: 49c3, but creates a list.

 -- Opcode: BUILD_SET (count)

     Works as *note BUILD_TUPLE: 49c3, but creates a set.

 -- Opcode: BUILD_MAP (count)

     Pushes a new dictionary object onto the stack.  Pops ‘2 * count’
     items so that the dictionary holds 'count' entries: ‘{...,
     STACK[-4]: STACK[-3], STACK[-2]: STACK[-1]}’.

     Changed in version 3.5: The dictionary is created from stack items
     instead of creating an empty dictionary pre-sized to hold 'count'
     items.

 -- Opcode: BUILD_CONST_KEY_MAP (count)

     The version of *note BUILD_MAP: 17f2. specialized for constant
     keys.  Pops the top element on the stack which contains a tuple of
     keys, then starting from ‘STACK[-2]’, pops 'count' values to form
     values in the built dictionary.

     Added in version 3.6.

 -- Opcode: BUILD_STRING (count)

     Concatenates 'count' strings from the stack and pushes the
     resulting string onto the stack.

     Added in version 3.6.

 -- Opcode: LIST_EXTEND (i)

     Implements:

          seq = STACK.pop()
          list.extend(STACK[-i], seq)

     Used to build lists.

     Added in version 3.9.

 -- Opcode: SET_UPDATE (i)

     Implements:

          seq = STACK.pop()
          set.update(STACK[-i], seq)

     Used to build sets.

     Added in version 3.9.

 -- Opcode: DICT_UPDATE (i)

     Implements:

          map = STACK.pop()
          dict.update(STACK[-i], map)

     Used to build dicts.

     Added in version 3.9.

 -- Opcode: DICT_MERGE (i)

     Like *note DICT_UPDATE: 49c8. but raises an exception for duplicate
     keys.

     Added in version 3.9.

 -- Opcode: LOAD_ATTR (namei)

     If the low bit of ‘namei’ is not set, this replaces ‘STACK[-1]’
     with ‘getattr(STACK[-1], co_names[namei>>1])’.

     If the low bit of ‘namei’ is set, this will attempt to load a
     method named ‘co_names[namei>>1]’ from the ‘STACK[-1]’ object.
     ‘STACK[-1]’ is popped.  This bytecode distinguishes two cases: if
     ‘STACK[-1]’ has a method with the correct name, the bytecode pushes
     the unbound method and ‘STACK[-1]’.  ‘STACK[-1]’ will be used as
     the first argument (‘self’) by *note CALL: 70a. or *note CALL_KW:
     17f3. when calling the unbound method.  Otherwise, ‘NULL’ and the
     object returned by the attribute lookup are pushed.

     Changed in version 3.12: If the low bit of ‘namei’ is set, then a
     ‘NULL’ or ‘self’ is pushed to the stack before the attribute or
     unbound method respectively.

 -- Opcode: LOAD_SUPER_ATTR (namei)

     This opcode implements *note super(): 4de, both in its
     zero-argument and two-argument forms (e.g.  ‘super().method()’,
     ‘super().attr’ and ‘super(cls, self).method()’, ‘super(cls,
     self).attr’).

     It pops three values from the stack (from top of stack down):

        * ‘self’: the first argument to the current method

        * ‘cls’: the class within which the current method was defined

        * the global ‘super’

     With respect to its argument, it works similarly to *note
     LOAD_ATTR: 4e1, except that ‘namei’ is shifted left by 2 bits
     instead of 1.

     The low bit of ‘namei’ signals to attempt a method load, as with
     *note LOAD_ATTR: 4e1, which results in pushing ‘NULL’ and the
     loaded method.  When it is unset a single value is pushed to the
     stack.

     The second-low bit of ‘namei’, if set, means that this was a
     two-argument call to *note super(): 4de. (unset means
     zero-argument).

     Added in version 3.12.

 -- Opcode: COMPARE_OP (opname)

     Performs a Boolean operation.  The operation name can be found in
     ‘cmp_op[opname >> 5]’.  If the fifth-lowest bit of ‘opname’ is set
     (‘opname & 16’), the result should be coerced to ‘bool’.

     Changed in version 3.13: The fifth-lowest bit of the oparg now
     indicates a forced conversion to *note bool: 46b.

 -- Opcode: IS_OP (invert)

     Performs ‘is’ comparison, or ‘is not’ if ‘invert’ is 1.

     Added in version 3.9.

 -- Opcode: CONTAINS_OP (invert)

     Performs ‘in’ comparison, or ‘not in’ if ‘invert’ is 1.

     Added in version 3.9.

 -- Opcode: IMPORT_NAME (namei)

     Imports the module ‘co_names[namei]’.  ‘STACK[-1]’ and ‘STACK[-2]’
     are popped and provide the 'fromlist' and 'level' arguments of
     *note __import__(): 8dd.  The module object is pushed onto the
     stack.  The current namespace is not affected: for a proper import
     statement, a subsequent *note STORE_FAST: 1802. instruction
     modifies the namespace.

 -- Opcode: IMPORT_FROM (namei)

     Loads the attribute ‘co_names[namei]’ from the module found in
     ‘STACK[-1]’.  The resulting object is pushed onto the stack, to be
     subsequently stored by a *note STORE_FAST: 1802. instruction.

 -- Opcode: JUMP_FORWARD (delta)

     Increments bytecode counter by 'delta'.

 -- Opcode: JUMP_BACKWARD (delta)

     Decrements bytecode counter by 'delta'.  Checks for interrupts.

     Added in version 3.11.

 -- Opcode: JUMP_BACKWARD_NO_INTERRUPT (delta)

     Decrements bytecode counter by 'delta'.  Does not check for
     interrupts.

     Added in version 3.11.

 -- Opcode: POP_JUMP_IF_TRUE (delta)

     If ‘STACK[-1]’ is true, increments the bytecode counter by 'delta'.
     ‘STACK[-1]’ is popped.

     Changed in version 3.11: The oparg is now a relative delta rather
     than an absolute target.  This opcode is a pseudo-instruction,
     replaced in final bytecode by the directed versions
     (forward/backward).

     Changed in version 3.12: This is no longer a pseudo-instruction.

     Changed in version 3.13: This instruction now requires an exact
     *note bool: 46b. operand.

 -- Opcode: POP_JUMP_IF_FALSE (delta)

     If ‘STACK[-1]’ is false, increments the bytecode counter by
     'delta'.  ‘STACK[-1]’ is popped.

     Changed in version 3.11: The oparg is now a relative delta rather
     than an absolute target.  This opcode is a pseudo-instruction,
     replaced in final bytecode by the directed versions
     (forward/backward).

     Changed in version 3.12: This is no longer a pseudo-instruction.

     Changed in version 3.13: This instruction now requires an exact
     *note bool: 46b. operand.

 -- Opcode: POP_JUMP_IF_NOT_NONE (delta)

     If ‘STACK[-1]’ is not ‘None’, increments the bytecode counter by
     'delta'.  ‘STACK[-1]’ is popped.

     Added in version 3.11.

     Changed in version 3.12: This is no longer a pseudo-instruction.

 -- Opcode: POP_JUMP_IF_NONE (delta)

     If ‘STACK[-1]’ is ‘None’, increments the bytecode counter by
     'delta'.  ‘STACK[-1]’ is popped.

     Added in version 3.11.

     Changed in version 3.12: This is no longer a pseudo-instruction.

 -- Opcode: FOR_ITER (delta)

     ‘STACK[-1]’ is an *note iterator: 1ac.  Call its *note __next__():
     1315. method.  If this yields a new value, push it on the stack
     (leaving the iterator below it).  If the iterator indicates it is
     exhausted then the byte code counter is incremented by 'delta'.

     Changed in version 3.12: Up until 3.11 the iterator was popped when
     it was exhausted.

 -- Opcode: LOAD_GLOBAL (namei)

     Loads the global named ‘co_names[namei>>1]’ onto the stack.

     Changed in version 3.11: If the low bit of ‘namei’ is set, then a
     ‘NULL’ is pushed to the stack before the global variable.

 -- Opcode: LOAD_FAST (var_num)

     Pushes a reference to the local ‘co_varnames[var_num]’ onto the
     stack.

     Changed in version 3.12: This opcode is now only used in situations
     where the local variable is guaranteed to be initialized.  It
     cannot raise *note UnboundLocalError: 1586.

 -- Opcode: LOAD_FAST_LOAD_FAST (var_nums)

     Pushes references to ‘co_varnames[var_nums >> 4]’ and
     ‘co_varnames[var_nums & 15]’ onto the stack.

     Added in version 3.13.

 -- Opcode: LOAD_FAST_CHECK (var_num)

     Pushes a reference to the local ‘co_varnames[var_num]’ onto the
     stack, raising an *note UnboundLocalError: 1586. if the local
     variable has not been initialized.

     Added in version 3.12.

 -- Opcode: LOAD_FAST_AND_CLEAR (var_num)

     Pushes a reference to the local ‘co_varnames[var_num]’ onto the
     stack (or pushes ‘NULL’ onto the stack if the local variable has
     not been initialized) and sets ‘co_varnames[var_num]’ to ‘NULL’.

     Added in version 3.12.

 -- Opcode: STORE_FAST (var_num)

     Stores ‘STACK.pop()’ into the local ‘co_varnames[var_num]’.

 -- Opcode: STORE_FAST_STORE_FAST (var_nums)

     Stores ‘STACK[-1]’ into ‘co_varnames[var_nums >> 4]’ and
     ‘STACK[-2]’ into ‘co_varnames[var_nums & 15]’.

     Added in version 3.13.

 -- Opcode: STORE_FAST_LOAD_FAST (var_nums)

     Stores ‘STACK.pop()’ into the local ‘co_varnames[var_nums >> 4]’
     and pushes a reference to the local ‘co_varnames[var_nums & 15]’
     onto the stack.

     Added in version 3.13.

 -- Opcode: DELETE_FAST (var_num)

     Deletes local ‘co_varnames[var_num]’.

 -- Opcode: MAKE_CELL (i)

     Creates a new cell in slot ‘i’.  If that slot is nonempty then that
     value is stored into the new cell.

     Added in version 3.11.

 -- Opcode: LOAD_DEREF (i)

     Loads the cell contained in slot ‘i’ of the “fast locals” storage.
     Pushes a reference to the object the cell contains on the stack.

     Changed in version 3.11: ‘i’ is no longer offset by the length of
     *note co_varnames: 20f1.

 -- Opcode: LOAD_FROM_DICT_OR_DEREF (i)

     Pops a mapping off the stack and looks up the name associated with
     slot ‘i’ of the “fast locals” storage in this mapping.  If the name
     is not found there, loads it from the cell contained in slot ‘i’,
     similar to *note LOAD_DEREF: 49d3.  This is used for loading *note
     closure variables: 20f4. in class bodies (which previously used
     ‘LOAD_CLASSDEREF’) and in *note annotation scopes: 188. within
     class bodies.

     Added in version 3.12.

 -- Opcode: STORE_DEREF (i)

     Stores ‘STACK.pop()’ into the cell contained in slot ‘i’ of the
     “fast locals” storage.

     Changed in version 3.11: ‘i’ is no longer offset by the length of
     *note co_varnames: 20f1.

 -- Opcode: DELETE_DEREF (i)

     Empties the cell contained in slot ‘i’ of the “fast locals”
     storage.  Used by the *note del: 18c2. statement.

     Added in version 3.2.

     Changed in version 3.11: ‘i’ is no longer offset by the length of
     *note co_varnames: 20f1.

 -- Opcode: COPY_FREE_VARS (n)

     Copies the ‘n’ *note free (closure) variables: 20f4. from the
     closure into the frame.  Removes the need for special code on the
     caller’s side when calling closures.

     Added in version 3.11.

 -- Opcode: RAISE_VARARGS (argc)

     Raises an exception using one of the 3 forms of the ‘raise’
     statement, depending on the value of 'argc':

        * 0: ‘raise’ (re-raise previous exception)

        * 1: ‘raise STACK[-1]’ (raise exception instance or type at
          ‘STACK[-1]’)

        * 2: ‘raise STACK[-2] from STACK[-1]’ (raise exception instance
          or type at ‘STACK[-2]’ with ‘__cause__’ set to ‘STACK[-1]’)

 -- Opcode: CALL (argc)

     Calls a callable object with the number of arguments specified by
     ‘argc’.  On the stack are (in ascending order):

        * The callable

        * ‘self’ or ‘NULL’

        * The remaining positional arguments

     ‘argc’ is the total of the positional arguments, excluding ‘self’.

     ‘CALL’ pops all arguments and the callable object off the stack,
     calls the callable object with those arguments, and pushes the
     return value returned by the callable object.

     Added in version 3.11.

     Changed in version 3.13: The callable now always appears at the
     same position on the stack.

     Changed in version 3.13: Calls with keyword arguments are now
     handled by *note CALL_KW: 17f3.

 -- Opcode: CALL_KW (argc)

     Calls a callable object with the number of arguments specified by
     ‘argc’, including one or more named arguments.  On the stack are
     (in ascending order):

        * The callable

        * ‘self’ or ‘NULL’

        * The remaining positional arguments

        * The named arguments

        * A *note tuple: 373. of keyword argument names

     ‘argc’ is the total of the positional and named arguments,
     excluding ‘self’.  The length of the tuple of keyword argument
     names is the number of named arguments.

     ‘CALL_KW’ pops all arguments, the keyword names, and the callable
     object off the stack, calls the callable object with those
     arguments, and pushes the return value returned by the callable
     object.

     Added in version 3.13.

 -- Opcode: CALL_FUNCTION_EX (flags)

     Calls a callable object with variable set of positional and keyword
     arguments.  If the lowest bit of 'flags' is set, the top of the
     stack contains a mapping object containing additional keyword
     arguments.  Before the callable is called, the mapping object and
     iterable object are each “unpacked” and their contents passed in as
     keyword and positional arguments respectively.  ‘CALL_FUNCTION_EX’
     pops all arguments and the callable object off the stack, calls the
     callable object with those arguments, and pushes the return value
     returned by the callable object.

     Added in version 3.6.

 -- Opcode: PUSH_NULL

     Pushes a ‘NULL’ to the stack.  Used in the call sequence to match
     the ‘NULL’ pushed by *note LOAD_METHOD: c3f. for non-method calls.

     Added in version 3.11.

 -- Opcode: MAKE_FUNCTION

     Pushes a new function object on the stack built from the code
     object at ‘STACK[-1]’.

     Changed in version 3.10: Flag value ‘0x04’ is a tuple of strings
     instead of dictionary

     Changed in version 3.11: Qualified name at ‘STACK[-1]’ was removed.

     Changed in version 3.13: Extra function attributes on the stack,
     signaled by oparg flags, were removed.  They now use *note
     SET_FUNCTION_ATTRIBUTE: 49d7.

 -- Opcode: SET_FUNCTION_ATTRIBUTE (flag)

     Sets an attribute on a function object.  Expects the function at
     ‘STACK[-1]’ and the attribute value to set at ‘STACK[-2]’; consumes
     both and leaves the function at ‘STACK[-1]’.  The flag determines
     which attribute to set:

        * ‘0x01’ a tuple of default values for positional-only and
          positional-or-keyword parameters in positional order

        * ‘0x02’ a dictionary of keyword-only parameters’ default values

        * ‘0x04’ a tuple of strings containing parameters’ annotations

        * ‘0x08’ a tuple containing cells for free variables, making a
          closure

     Added in version 3.13.

 -- Opcode: BUILD_SLICE (argc)

     Pushes a slice object on the stack.  'argc' must be 2 or 3.  If it
     is 2, implements:

          end = STACK.pop()
          start = STACK.pop()
          STACK.append(slice(start, end))

     if it is 3, implements:

          step = STACK.pop()
          end = STACK.pop()
          start = STACK.pop()
          STACK.append(slice(start, end, step))

     See the *note slice(): 46c. built-in function for more information.

 -- Opcode: EXTENDED_ARG (ext)

     Prefixes any opcode which has an argument too big to fit into the
     default one byte.  'ext' holds an additional byte which act as
     higher bits in the argument.  For each opcode, at most three
     prefixal ‘EXTENDED_ARG’ are allowed, forming an argument from
     two-byte to four-byte.

 -- Opcode: CONVERT_VALUE (oparg)

     Convert value to a string, depending on ‘oparg’:

          value = STACK.pop()
          result = func(value)
          STACK.append(result)

        * ‘oparg == 1’: call *note str(): 44f. on 'value'

        * ‘oparg == 2’: call *note repr(): 803. on 'value'

        * ‘oparg == 3’: call *note ascii(): 1434. on 'value'

     Used for implementing formatted string literals (f-strings).

     Added in version 3.13.

 -- Opcode: FORMAT_SIMPLE

     Formats the value on top of stack:

          value = STACK.pop()
          result = value.__format__("")
          STACK.append(result)

     Used for implementing formatted string literals (f-strings).

     Added in version 3.13.

 -- Opcode: FORMAT_WITH_SPEC

     Formats the given value with the given format spec:

          spec = STACK.pop()
          value = STACK.pop()
          result = value.__format__(spec)
          STACK.append(result)

     Used for implementing formatted string literals (f-strings).

     Added in version 3.13.

 -- Opcode: MATCH_CLASS (count)

     ‘STACK[-1]’ is a tuple of keyword attribute names, ‘STACK[-2]’ is
     the class being matched against, and ‘STACK[-3]’ is the match
     subject.  'count' is the number of positional sub-patterns.

     Pop ‘STACK[-1]’, ‘STACK[-2]’, and ‘STACK[-3]’.  If ‘STACK[-3]’ is
     an instance of ‘STACK[-2]’ and has the positional and keyword
     attributes required by 'count' and ‘STACK[-1]’, push a tuple of
     extracted attributes.  Otherwise, push ‘None’.

     Added in version 3.10.

     Changed in version 3.11: Previously, this instruction also pushed a
     boolean value indicating success (‘True’) or failure (‘False’).

 -- Opcode: RESUME (context)

     A no-op.  Performs internal tracing, debugging and optimization
     checks.

     The ‘context’ oparand consists of two parts.  The lowest two bits
     indicate where the ‘RESUME’ occurs:

        * ‘0’ The start of a function, which is neither a generator,
          coroutine nor an async generator

        * ‘1’ After a ‘yield’ expression

        * ‘2’ After a ‘yield from’ expression

        * ‘3’ After an ‘await’ expression

     The next bit is ‘1’ if the RESUME is at except-depth ‘1’, and ‘0’
     otherwise.

     Added in version 3.11.

     Changed in version 3.13: The oparg value changed to include
     information about except-depth

 -- Opcode: RETURN_GENERATOR

     Create a generator, coroutine, or async generator from the current
     frame.  Used as first opcode of in code object for the above
     mentioned callables.  Clear the current frame and return the newly
     created generator.

     Added in version 3.11.

 -- Opcode: SEND (delta)

     Equivalent to ‘STACK[-1] = STACK[-2].send(STACK[-1])’.  Used in
     ‘yield from’ and ‘await’ statements.

     If the call raises *note StopIteration: c1b, pop the top value from
     the stack, push the exception’s ‘value’ attribute, and increment
     the bytecode counter by 'delta'.

     Added in version 3.11.

 -- Opcode: HAVE_ARGUMENT

     This is not really an opcode.  It identifies the dividing line
     between opcodes in the range [0,255] which don’t use their argument
     and those that do (‘< HAVE_ARGUMENT’ and ‘>= HAVE_ARGUMENT’,
     respectively).

     If your application uses pseudo instructions or specialized
     instructions, use the *note hasarg: 29e. collection instead.

     Changed in version 3.6: Now every instruction has an argument, but
     opcodes ‘< HAVE_ARGUMENT’ ignore it.  Before, only opcodes ‘>=
     HAVE_ARGUMENT’ had an argument.

     Changed in version 3.12: Pseudo instructions were added to the
     ‘dis’ module, and for them it is not true that comparison with
     ‘HAVE_ARGUMENT’ indicates whether they use their arg.

     Deprecated since version 3.13: Use *note hasarg: 29e. instead.

 -- Opcode: CALL_INTRINSIC_1

     Calls an intrinsic function with one argument.  Passes ‘STACK[-1]’
     as the argument and sets ‘STACK[-1]’ to the result.  Used to
     implement functionality that is not performance critical.

     The operand determines which intrinsic function is called:

     Operand                                 Description
                                             
     --------------------------------------------------------------------------------
                                             
     ‘INTRINSIC_1_INVALID’                   Not valid
                                             
                                             
     ‘INTRINSIC_PRINT’                       Prints the argument to standard out.
                                             Used in the REPL.
                                             
                                             
     ‘INTRINSIC_IMPORT_STAR’                 Performs ‘import *’ for the named
                                             module.
                                             
                                             
     ‘INTRINSIC_STOPITERATION_ERROR’         Extracts the return value from a
                                             ‘StopIteration’ exception.
                                             
                                             
     ‘INTRINSIC_ASYNC_GEN_WRAP’              Wraps an async generator value
                                             
                                             
     ‘INTRINSIC_UNARY_POSITIVE’              Performs the unary ‘+’ operation
                                             
                                             
     ‘INTRINSIC_LIST_TO_TUPLE’               Converts a list to a tuple
                                             
                                             
     ‘INTRINSIC_TYPEVAR’                     Creates a *note typing.TypeVar: 15d.
                                             
                                             
     ‘INTRINSIC_PARAMSPEC’                   Creates a
                                             *note typing.ParamSpec: 15e.
                                             
                                             
     ‘INTRINSIC_TYPEVARTUPLE’                Creates a
                                             *note typing.TypeVarTuple: 15f.
                                             
                                             
     ‘INTRINSIC_SUBSCRIPT_GENERIC’           Returns *note typing.Generic: 15fb.
                                             subscripted with the argument
                                             
                                             
     ‘INTRINSIC_TYPEALIAS’                   Creates a
                                             *note typing.TypeAliasType: 458.;
                                             used in the *note type: 43b.
                                             statement.  The argument is a tuple
                                             of the type alias’s name, type
                                             parameters, and value.
                                             

     Added in version 3.12.

 -- Opcode: CALL_INTRINSIC_2

     Calls an intrinsic function with two arguments.  Used to implement
     functionality that is not performance critical:

          arg2 = STACK.pop()
          arg1 = STACK.pop()
          result = intrinsic2(arg1, arg2)
          STACK.append(result)

     The operand determines which intrinsic function is called:

     Operand                                      Description
                                                  
     -------------------------------------------------------------------------------------
                                                  
     ‘INTRINSIC_2_INVALID’                        Not valid
                                                  
                                                  
     ‘INTRINSIC_PREP_RERAISE_STAR’                Calculates the
                                                  *note ExceptionGroup: 1b6. to raise
                                                  from a ‘try-except*’.
                                                  
                                                  
     ‘INTRINSIC_TYPEVAR_WITH_BOUND’               Creates a *note typing.TypeVar: 15d.
                                                  with a bound.
                                                  
                                                  
     ‘INTRINSIC_TYPEVAR_WITH_CONSTRAINTS’         Creates a *note typing.TypeVar: 15d.
                                                  with constraints.
                                                  
                                                  
     ‘INTRINSIC_SET_FUNCTION_TYPE_PARAMS’         Sets the ‘__type_params__’ attribute
                                                  of a function.
                                                  

     Added in version 3.12.

'Pseudo-instructions'

These opcodes do not appear in Python bytecode.  They are used by the
compiler but are replaced by real opcodes or removed before bytecode is
generated.

 -- Opcode: SETUP_FINALLY (target)

     Set up an exception handler for the following code block.  If an
     exception occurs, the value stack level is restored to its current
     state and control is transferred to the exception handler at
     ‘target’.

 -- Opcode: SETUP_CLEANUP (target)

     Like ‘SETUP_FINALLY’, but in case of an exception also pushes the
     last instruction (‘lasti’) to the stack so that ‘RERAISE’ can
     restore it.  If an exception occurs, the value stack level and the
     last instruction on the frame are restored to their current state,
     and control is transferred to the exception handler at ‘target’.

 -- Opcode: SETUP_WITH (target)

     Like ‘SETUP_CLEANUP’, but in case of an exception one more item is
     popped from the stack before control is transferred to the
     exception handler at ‘target’.

     This variant is used in *note with: 5d5. and *note async with: 5d8.
     constructs, which push the return value of the context manager’s
     *note __enter__(): 5cb. or *note __aenter__(): 2181. to the stack.

 -- Opcode: POP_BLOCK

     Marks the end of the code block associated with the last
     ‘SETUP_FINALLY’, ‘SETUP_CLEANUP’ or ‘SETUP_WITH’.

 -- Opcode: JUMP

 -- Opcode: JUMP_NO_INTERRUPT

     Undirected relative jump instructions which are replaced by their
     directed (forward/backward) counterparts by the assembler.

 -- Opcode: LOAD_CLOSURE (i)

     Pushes a reference to the cell contained in slot ‘i’ of the “fast
     locals” storage.

     Note that ‘LOAD_CLOSURE’ is replaced with ‘LOAD_FAST’ in the
     assembler.

     Changed in version 3.13: This opcode is now a pseudo-instruction.

 -- Opcode: LOAD_METHOD

     Optimized unbound method lookup.  Emitted as a ‘LOAD_ATTR’ opcode
     with a flag set in the arg.


File: python.info,  Node: Opcode collections,  Prev: Python Bytecode Instructions,  Up: dis — Disassembler for Python bytecode

5.32.10.5 Opcode collections
............................

These collections are provided for automatic introspection of bytecode
instructions:

Changed in version 3.12: The collections now contain pseudo instructions
and instrumented instructions as well.  These are opcodes with values
‘>= MIN_PSEUDO_OPCODE’ and ‘>= MIN_INSTRUMENTED_OPCODE’.

 -- Data: dis.opname

     Sequence of operation names, indexable using the bytecode.

 -- Data: dis.opmap

     Dictionary mapping operation names to bytecodes.

 -- Data: dis.cmp_op

     Sequence of all compare operation names.

 -- Data: dis.hasarg

     Sequence of bytecodes that use their argument.

     Added in version 3.12.

 -- Data: dis.hasconst

     Sequence of bytecodes that access a constant.

 -- Data: dis.hasfree

     Sequence of bytecodes that access a *note free (closure) variable:
     20f4.  ‘free’ in this context refers to names in the current scope
     that are referenced by inner scopes or names in outer scopes that
     are referenced from this scope.  It does 'not' include references
     to global or builtin scopes.

 -- Data: dis.hasname

     Sequence of bytecodes that access an attribute by name.

 -- Data: dis.hasjump

     Sequence of bytecodes that have a jump target.  All jumps are
     relative.

     Added in version 3.13.

 -- Data: dis.haslocal

     Sequence of bytecodes that access a local variable.

 -- Data: dis.hascompare

     Sequence of bytecodes of Boolean operations.

 -- Data: dis.hasexc

     Sequence of bytecodes that set an exception handler.

     Added in version 3.12.

 -- Data: dis.hasjrel

     Sequence of bytecodes that have a relative jump target.

     Deprecated since version 3.13: All jumps are now relative.  Use
     *note hasjump: 49e7.

 -- Data: dis.hasjabs

     Sequence of bytecodes that have an absolute jump target.

     Deprecated since version 3.13: All jumps are now relative.  This
     list is empty.


File: python.info,  Node: pickletools — Tools for pickle developers,  Prev: dis — Disassembler for Python bytecode,  Up: Python Language Services

5.32.11 ‘pickletools’ — Tools for pickle developers
---------------------------------------------------

'Source code:' Lib/pickletools.py(1)

__________________________________________________________________

This module contains various constants relating to the intimate details
of the *note pickle: a6. module, some lengthy comments about the
implementation, and a few useful functions for analyzing pickled data.
The contents of this module are useful for Python core developers who
are working on the ‘pickle’; ordinary users of the ‘pickle’ module
probably won’t find the ‘pickletools’ module relevant.

* Menu:

* Command line usage::
* Programmatic Interface: Programmatic Interface<2>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pickletools.py


File: python.info,  Node: Command line usage,  Next: Programmatic Interface<2>,  Up: pickletools — Tools for pickle developers

5.32.11.1 Command line usage
............................

Added in version 3.2.

When invoked from the command line, ‘python -m pickletools’ will
disassemble the contents of one or more pickle files.  Note that if you
want to see the Python object stored in the pickle rather than the
details of pickle format, you may want to use ‘-m pickle’ instead.
However, when the pickle file that you want to examine comes from an
untrusted source, ‘-m pickletools’ is a safer option because it does not
execute pickle bytecode.

For example, with a tuple ‘(1, 2)’ pickled in file ‘x.pickle’:

     $ python -m pickle x.pickle
     (1, 2)

     $ python -m pickletools x.pickle
         0: \x80 PROTO      3
         2: K    BININT1    1
         4: K    BININT1    2
         6: \x86 TUPLE2
         7: q    BINPUT     0
         9: .    STOP
     highest protocol among opcodes = 2

* Menu:

* Command line options: Command line options<2>.


File: python.info,  Node: Command line options<2>,  Up: Command line usage

5.32.11.2 Command line options
..............................

 -- Option: -a, --annotate

     Annotate each line with a short opcode description.

 -- Option: -o, --output=<file>

     Name of a file where the output should be written.

 -- Option: -l, --indentlevel=<num>

     The number of blanks by which to indent a new MARK level.

 -- Option: -m, --memo

     When multiple objects are disassembled, preserve memo between
     disassemblies.

 -- Option: -p, --preamble=<preamble>

     When more than one pickle file are specified, print given preamble
     before each disassembly.


File: python.info,  Node: Programmatic Interface<2>,  Prev: Command line usage,  Up: pickletools — Tools for pickle developers

5.32.11.3 Programmatic Interface
................................

 -- Function: pickletools.dis (pickle, out=None, memo=None,
          indentlevel=4, annotate=0)

     Outputs a symbolic disassembly of the pickle to the file-like
     object 'out', defaulting to ‘sys.stdout’.  'pickle' can be a string
     or a file-like object.  'memo' can be a Python dictionary that will
     be used as the pickle’s memo; it can be used to perform
     disassemblies across multiple pickles created by the same pickler.
     Successive levels, indicated by ‘MARK’ opcodes in the stream, are
     indented by 'indentlevel' spaces.  If a nonzero value is given to
     'annotate', each opcode in the output is annotated with a short
     description.  The value of 'annotate' is used as a hint for the
     column where annotation should start.

     Changed in version 3.2: Added the 'annotate' parameter.

 -- Function: pickletools.genops (pickle)

     Provides an *note iterator: 1ac. over all of the opcodes in a
     pickle, returning a sequence of ‘(opcode, arg, pos)’ triples.
     'opcode' is an instance of an ‘OpcodeInfo’ class; 'arg' is the
     decoded value, as a Python object, of the opcode’s argument; 'pos'
     is the position at which this opcode is located.  'pickle' can be a
     string or a file-like object.

 -- Function: pickletools.optimize (picklestring)

     Returns a new equivalent pickle string after eliminating unused
     ‘PUT’ opcodes.  The optimized pickle is shorter, takes less
     transmission time, requires less storage space, and unpickles more
     efficiently.


File: python.info,  Node: MS Windows Specific Services,  Next: Unix-specific services,  Prev: Python Language Services,  Up: The Python Standard Library

5.33 MS Windows Specific Services
=================================

This chapter describes modules that are only available on MS Windows
platforms.

* Menu:

* msvcrt — Useful routines from the MS VC++ runtime::
* winreg — Windows registry access::
* winsound — Sound-playing interface for Windows::


File: python.info,  Node: msvcrt — Useful routines from the MS VC++ runtime,  Next: winreg — Windows registry access,  Up: MS Windows Specific Services

5.33.1 ‘msvcrt’ — Useful routines from the MS VC++ runtime
----------------------------------------------------------

__________________________________________________________________

These functions provide access to some useful capabilities on Windows
platforms.  Some higher-level modules use these functions to build the
Windows implementations of their services.  For example, the *note
getpass: 62. module uses this in the implementation of the *note
getpass(): 62. function.

Further documentation on these functions can be found in the Platform
API documentation.

The module implements both the normal and wide char variants of the
console I/O api.  The normal API deals only with ASCII characters and is
of limited use for internationalized applications.  The wide char API
should be used where ever possible.

*note Availability: 1ef7.: Windows.

Changed in version 3.3: Operations in this module now raise *note
OSError: 41a. where *note IOError: 1090. was raised.

* Menu:

* File Operations::
* Console I/O::
* Other Functions::


File: python.info,  Node: File Operations,  Next: Console I/O,  Up: msvcrt — Useful routines from the MS VC++ runtime

5.33.1.1 File Operations
........................

 -- Function: msvcrt.locking (fd, mode, nbytes)

     Lock part of a file based on file descriptor 'fd' from the C
     runtime.  Raises *note OSError: 41a. on failure.  The locked region
     of the file extends from the current file position for 'nbytes'
     bytes, and may continue beyond the end of the file.  'mode' must be
     one of the ‘LK_*’ constants listed below.  Multiple regions in a
     file may be locked at the same time, but may not overlap.  Adjacent
     regions are not merged; they must be unlocked individually.

     Raises an *note auditing event: 1a15. ‘msvcrt.locking’ with
     arguments ‘fd’, ‘mode’, ‘nbytes’.

 -- Data: msvcrt.LK_LOCK
 -- Data: msvcrt.LK_RLCK

     Locks the specified bytes.  If the bytes cannot be locked, the
     program immediately tries again after 1 second.  If, after 10
     attempts, the bytes cannot be locked, *note OSError: 41a. is
     raised.

 -- Data: msvcrt.LK_NBLCK
 -- Data: msvcrt.LK_NBRLCK

     Locks the specified bytes.  If the bytes cannot be locked, *note
     OSError: 41a. is raised.

 -- Data: msvcrt.LK_UNLCK

     Unlocks the specified bytes, which must have been previously
     locked.

 -- Function: msvcrt.setmode (fd, flags)

     Set the line-end translation mode for the file descriptor 'fd'.  To
     set it to text mode, 'flags' should be *note os.O_TEXT: 2d52.; for
     binary, it should be *note os.O_BINARY: 2d43.

 -- Function: msvcrt.open_osfhandle (handle, flags)

     Create a C runtime file descriptor from the file handle 'handle'.
     The 'flags' parameter should be a bitwise OR of *note os.O_APPEND:
     2d45, *note os.O_RDONLY: 2d41, *note os.O_TEXT: 2d52. and *note
     os.O_NOINHERIT: 2d4d.  The returned file descriptor may be used as
     a parameter to *note os.fdopen(): 20e3. to create a file object.

     The file descriptor is inheritable by default.  Pass *note
     os.O_NOINHERIT: 2d4d. flag to make it non inheritable.

     Raises an *note auditing event: 1a15. ‘msvcrt.open_osfhandle’ with
     arguments ‘handle’, ‘flags’.

 -- Function: msvcrt.get_osfhandle (fd)

     Return the file handle for the file descriptor 'fd'.  Raises *note
     OSError: 41a. if 'fd' is not recognized.

     Raises an *note auditing event: 1a15. ‘msvcrt.get_osfhandle’ with
     argument ‘fd’.


File: python.info,  Node: Console I/O,  Next: Other Functions,  Prev: File Operations,  Up: msvcrt — Useful routines from the MS VC++ runtime

5.33.1.2 Console I/O
....................

 -- Function: msvcrt.kbhit ()

     Returns a nonzero value if a keypress is waiting to be read.
     Otherwise, return 0.

 -- Function: msvcrt.getch ()

     Read a keypress and return the resulting character as a byte
     string.  Nothing is echoed to the console.  This call will block if
     a keypress is not already available, but will not wait for ‘Enter’
     to be pressed.  If the pressed key was a special function key, this
     will return ‘'\000'’ or ‘'\xe0'’; the next call will return the
     keycode.  The ‘Control’-‘C’ keypress cannot be read with this
     function.

 -- Function: msvcrt.getwch ()

     Wide char variant of *note getch(): 4a0e, returning a Unicode
     value.

 -- Function: msvcrt.getche ()

     Similar to *note getch(): 4a0e, but the keypress will be echoed if
     it represents a printable character.

 -- Function: msvcrt.getwche ()

     Wide char variant of *note getche(): 4a0f, returning a Unicode
     value.

 -- Function: msvcrt.putch (char)

     Print the byte string 'char' to the console without buffering.

 -- Function: msvcrt.putwch (unicode_char)

     Wide char variant of *note putch(): 4a10, accepting a Unicode
     value.

 -- Function: msvcrt.ungetch (char)

     Cause the byte string 'char' to be “pushed back” into the console
     buffer; it will be the next character read by *note getch(): 4a0e.
     or *note getche(): 4a0f.

 -- Function: msvcrt.ungetwch (unicode_char)

     Wide char variant of *note ungetch(): 4a11, accepting a Unicode
     value.


File: python.info,  Node: Other Functions,  Prev: Console I/O,  Up: msvcrt — Useful routines from the MS VC++ runtime

5.33.1.3 Other Functions
........................

 -- Function: msvcrt.heapmin ()

     Force the ‘malloc()’ heap to clean itself up and return unused
     blocks to the operating system.  On failure, this raises *note
     OSError: 41a.

 -- Function: msvcrt.set_error_mode (mode)

     Changes the location where the C runtime writes an error message
     for an error that might end the program.  'mode' must be one of the
     ‘OUT_*’ constants listed below or *note REPORT_ERRMODE: 4a17.
     Returns the old setting or -1 if an error occurs.  Only available
     in *note debug build of Python: 1f9.

 -- Data: msvcrt.OUT_TO_DEFAULT

     Error sink is determined by the app’s type.  Only available in
     *note debug build of Python: 1f9.

 -- Data: msvcrt.OUT_TO_STDERR

     Error sink is a standard error.  Only available in *note debug
     build of Python: 1f9.

 -- Data: msvcrt.OUT_TO_MSGBOX

     Error sink is a message box.  Only available in *note debug build
     of Python: 1f9.

 -- Data: msvcrt.REPORT_ERRMODE

     Report the current error mode value.  Only available in *note debug
     build of Python: 1f9.

 -- Function: msvcrt.CrtSetReportMode (type, mode)

     Specifies the destination or destinations for a specific report
     type generated by ‘_CrtDbgReport()’ in the MS VC++ runtime.  'type'
     must be one of the ‘CRT_*’ constants listed below.  'mode' must be
     one of the ‘CRTDBG_*’ constants listed below.  Only available in
     *note debug build of Python: 1f9.

 -- Function: msvcrt.CrtSetReportFile (type, file)

     After you use *note CrtSetReportMode(): 4a1b. to specify *note
     CRTDBG_MODE_FILE: 4a1d, you can specify the file handle to receive
     the message text.  'type' must be one of the ‘CRT_*’ constants
     listed below.  'file' should be the file handle your want
     specified.  Only available in *note debug build of Python: 1f9.

 -- Data: msvcrt.CRT_WARN

     Warnings, messages, and information that doesn’t need immediate
     attention.

 -- Data: msvcrt.CRT_ERROR

     Errors, unrecoverable problems, and issues that require immediate
     attention.

 -- Data: msvcrt.CRT_ASSERT

     Assertion failures.

 -- Data: msvcrt.CRTDBG_MODE_DEBUG

     Writes the message to the debugger’s output window.

 -- Data: msvcrt.CRTDBG_MODE_FILE

     Writes the message to a user-supplied file handle.  *note
     CrtSetReportFile(): 4a1c. should be called to define the specific
     file or stream to use as the destination.

 -- Data: msvcrt.CRTDBG_MODE_WNDW

     Creates a message box to display the message along with the
     ‘Abort’, ‘Retry’, and ‘Ignore’ buttons.

 -- Data: msvcrt.CRTDBG_REPORT_MODE

     Returns current 'mode' for the specified 'type'.

 -- Data: msvcrt.CRT_ASSEMBLY_VERSION

     The CRT Assembly version, from the ‘crtassem.h’ header file.

 -- Data: msvcrt.VC_ASSEMBLY_PUBLICKEYTOKEN

     The VC Assembly public key token, from the ‘crtassem.h’ header
     file.

 -- Data: msvcrt.LIBRARIES_ASSEMBLY_NAME_PREFIX

     The Libraries Assembly name prefix, from the ‘crtassem.h’ header
     file.


File: python.info,  Node: winreg — Windows registry access,  Next: winsound — Sound-playing interface for Windows,  Prev: msvcrt — Useful routines from the MS VC++ runtime,  Up: MS Windows Specific Services

5.33.2 ‘winreg’ — Windows registry access
-----------------------------------------

__________________________________________________________________

These functions expose the Windows registry API to Python.  Instead of
using an integer as the registry handle, a *note handle object: 4a27. is
used to ensure that the handles are closed correctly, even if the
programmer neglects to explicitly close them.

*note Availability: 1ef7.: Windows.

Changed in version 3.3: Several functions in this module used to raise a
*note WindowsError: 1092, which is now an alias of *note OSError: 41a.

* Menu:

* Functions: Functions<13>.
* Constants: Constants<10>.
* Registry Handle Objects::


File: python.info,  Node: Functions<13>,  Next: Constants<10>,  Up: winreg — Windows registry access

5.33.2.1 Functions
..................

This module offers the following functions:

 -- Function: winreg.CloseKey (hkey)

     Closes a previously opened registry key.  The 'hkey' argument
     specifies a previously opened key.

          Note: If 'hkey' is not closed using this method (or via *note
          hkey.Close(): 4a2c.), it is closed when the 'hkey' object is
          destroyed by Python.

 -- Function: winreg.ConnectRegistry (computer_name, key)

     Establishes a connection to a predefined registry handle on another
     computer, and returns a *note handle object: 4a27.

     'computer_name' is the name of the remote computer, of the form
     ‘r"\\computername"’.  If ‘None’, the local computer is used.

     'key' is the predefined handle to connect to.

     The return value is the handle of the opened key.  If the function
     fails, an *note OSError: 41a. exception is raised.

     Raises an *note auditing event: 1a15. ‘winreg.ConnectRegistry’ with
     arguments ‘computer_name’, ‘key’.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.CreateKey (key, sub_key)

     Creates or opens the specified key, returning a *note handle
     object: 4a27.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that names the key this method opens or
     creates.

     If 'key' is one of the predefined keys, 'sub_key' may be ‘None’.
     In that case, the handle returned is the same key handle passed in
     to the function.

     If the key already exists, this function opens the existing key.

     The return value is the handle of the opened key.  If the function
     fails, an *note OSError: 41a. exception is raised.

     Raises an *note auditing event: 1a15. ‘winreg.CreateKey’ with
     arguments ‘key’, ‘sub_key’, ‘access’.

     Raises an *note auditing event: 1a15. ‘winreg.OpenKey/result’ with
     argument ‘key’.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.CreateKeyEx (key, sub_key, reserved=0,
          access=KEY_WRITE)

     Creates or opens the specified key, returning a *note handle
     object: 4a27.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that names the key this method opens or
     creates.

     'reserved' is a reserved integer, and must be zero.  The default is
     zero.

     'access' is an integer that specifies an access mask that describes
     the desired security access for the key.  Default is *note
     KEY_WRITE: 4a2e.  See *note Access Rights: 4a2f. for other allowed
     values.

     If 'key' is one of the predefined keys, 'sub_key' may be ‘None’.
     In that case, the handle returned is the same key handle passed in
     to the function.

     If the key already exists, this function opens the existing key.

     The return value is the handle of the opened key.  If the function
     fails, an *note OSError: 41a. exception is raised.

     Raises an *note auditing event: 1a15. ‘winreg.CreateKey’ with
     arguments ‘key’, ‘sub_key’, ‘access’.

     Raises an *note auditing event: 1a15. ‘winreg.OpenKey/result’ with
     argument ‘key’.

     Added in version 3.2.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.DeleteKey (key, sub_key)

     Deletes the specified key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that must be a subkey of the key identified
     by the 'key' parameter.  This value must not be ‘None’, and the key
     may not have subkeys.

     'This method can not delete keys with subkeys.'

     If the method succeeds, the entire key, including all of its
     values, is removed.  If the method fails, an *note OSError: 41a.
     exception is raised.

     Raises an *note auditing event: 1a15. ‘winreg.DeleteKey’ with
     arguments ‘key’, ‘sub_key’, ‘access’.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.DeleteKeyEx (key, sub_key, access=KEY_WOW64_64KEY,
          reserved=0)

     Deletes the specified key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that must be a subkey of the key identified
     by the 'key' parameter.  This value must not be ‘None’, and the key
     may not have subkeys.

     'reserved' is a reserved integer, and must be zero.  The default is
     zero.

     'access' is an integer that specifies an access mask that describes
     the desired security access for the key.  Default is *note
     KEY_WOW64_64KEY: 4a30.  On 32-bit Windows, the WOW64 constants are
     ignored.  See *note Access Rights: 4a2f. for other allowed values.

     'This method can not delete keys with subkeys.'

     If the method succeeds, the entire key, including all of its
     values, is removed.  If the method fails, an *note OSError: 41a.
     exception is raised.

     On unsupported Windows versions, *note NotImplementedError: 228. is
     raised.

     Raises an *note auditing event: 1a15. ‘winreg.DeleteKey’ with
     arguments ‘key’, ‘sub_key’, ‘access’.

     Added in version 3.2.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.DeleteValue (key, value)

     Removes a named value from a registry key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'value' is a string that identifies the value to remove.

     Raises an *note auditing event: 1a15. ‘winreg.DeleteValue’ with
     arguments ‘key’, ‘value’.

 -- Function: winreg.EnumKey (key, index)

     Enumerates subkeys of an open registry key, returning a string.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'index' is an integer that identifies the index of the key to
     retrieve.

     The function retrieves the name of one subkey each time it is
     called.  It is typically called repeatedly until an *note OSError:
     41a. exception is raised, indicating, no more values are available.

     Raises an *note auditing event: 1a15. ‘winreg.EnumKey’ with
     arguments ‘key’, ‘index’.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.EnumValue (key, index)

     Enumerates values of an open registry key, returning a tuple.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'index' is an integer that identifies the index of the value to
     retrieve.

     The function retrieves the name of one subkey each time it is
     called.  It is typically called repeatedly, until an *note OSError:
     41a. exception is raised, indicating no more values.

     The result is a tuple of 3 items:

     Index       Meaning
                 
     -------------------------------------------------------------
                 
     ‘0’         A string that identifies the value name
                 
                 
     ‘1’         An object that holds the value data, and whose
                 type depends on the underlying registry type
                 
                 
     ‘2’         An integer that identifies the type of the
                 value data (see table in docs for
                 *note SetValueEx(): 18a6.)
                 

     Raises an *note auditing event: 1a15. ‘winreg.EnumValue’ with
     arguments ‘key’, ‘index’.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.ExpandEnvironmentStrings (str)

     Expands environment variable placeholders ‘%NAME%’ in strings like
     *note REG_EXPAND_SZ: 4a31.:

          >>> ExpandEnvironmentStrings('%windir%')
          'C:\\Windows'

     Raises an *note auditing event: 1a15.
     ‘winreg.ExpandEnvironmentStrings’ with argument ‘str’.

 -- Function: winreg.FlushKey (key)

     Writes all the attributes of a key to the registry.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     It is not necessary to call ‘FlushKey()’ to change a key.  Registry
     changes are flushed to disk by the registry using its lazy flusher.
     Registry changes are also flushed to disk at system shutdown.
     Unlike *note CloseKey(): 4a2b, the ‘FlushKey()’ method returns only
     when all the data has been written to the registry.  An application
     should only call ‘FlushKey()’ if it requires absolute certainty
     that registry changes are on disk.

          Note: If you don’t know whether a ‘FlushKey()’ call is
          required, it probably isn’t.

 -- Function: winreg.LoadKey (key, sub_key, file_name)

     Creates a subkey under the specified key and stores registration
     information from a specified file into that subkey.

     'key' is a handle returned by *note ConnectRegistry(): 442f. or one
     of the constants *note HKEY_USERS: 4a33. or *note
     HKEY_LOCAL_MACHINE: 4a34.

     'sub_key' is a string that identifies the subkey to load.

     'file_name' is the name of the file to load registry data from.
     This file must have been created with the *note SaveKey(): 443a.
     function.  Under the file allocation table (FAT) file system, the
     filename may not have an extension.

     A call to ‘LoadKey()’ fails if the calling process does not have
     the ‘SE_RESTORE_PRIVILEGE’ privilege.  Note that privileges are
     different from permissions – see the RegLoadKey documentation(1)
     for more details.

     If 'key' is a handle returned by *note ConnectRegistry(): 442f,
     then the path specified in 'file_name' is relative to the remote
     computer.

     Raises an *note auditing event: 1a15. ‘winreg.LoadKey’ with
     arguments ‘key’, ‘sub_key’, ‘file_name’.

 -- Function: winreg.OpenKey (key, sub_key, reserved=0, access=KEY_READ)
 -- Function: winreg.OpenKeyEx (key, sub_key, reserved=0,
          access=KEY_READ)

     Opens the specified key, returning a *note handle object: 4a27.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that identifies the sub_key to open.

     'reserved' is a reserved integer, and must be zero.  The default is
     zero.

     'access' is an integer that specifies an access mask that describes
     the desired security access for the key.  Default is *note
     KEY_READ: 4a36.  See *note Access Rights: 4a2f. for other allowed
     values.

     The result is a new handle to the specified key.

     If the function fails, *note OSError: 41a. is raised.

     Raises an *note auditing event: 1a15. ‘winreg.OpenKey’ with
     arguments ‘key’, ‘sub_key’, ‘access’.

     Raises an *note auditing event: 1a15. ‘winreg.OpenKey/result’ with
     argument ‘key’.

     Changed in version 3.2: Allow the use of named arguments.

     Changed in version 3.3: See *note above: 4a28.

 -- Function: winreg.QueryInfoKey (key)

     Returns information about a key, as a tuple.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     The result is a tuple of 3 items:

     Index       Meaning
                 
     --------------------------------------------------------------
                 
     ‘0’         An integer giving the number of sub keys this
                 key has.
                 
                 
     ‘1’         An integer giving the number of values this key
                 has.
                 
                 
     ‘2’         An integer giving when the key was last
                 modified (if available) as 100’s of nanoseconds
                 since Jan 1, 1601.
                 

     Raises an *note auditing event: 1a15. ‘winreg.QueryInfoKey’ with
     argument ‘key’.

 -- Function: winreg.QueryValue (key, sub_key)

     Retrieves the unnamed value for a key, as a string.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that holds the name of the subkey with which
     the value is associated.  If this parameter is ‘None’ or empty, the
     function retrieves the value set by the *note SetValue(): 443b.
     method for the key identified by 'key'.

     Values in the registry have name, type, and data components.  This
     method retrieves the data for a key’s first value that has a ‘NULL’
     name.  But the underlying API call doesn’t return the type, so
     always use *note QueryValueEx(): 15cf. if possible.

     Raises an *note auditing event: 1a15. ‘winreg.QueryValue’ with
     arguments ‘key’, ‘sub_key’, ‘value_name’.

 -- Function: winreg.QueryValueEx (key, value_name)

     Retrieves the type and data for a specified value name associated
     with an open registry key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'value_name' is a string indicating the value to query.

     The result is a tuple of 2 items:

     Index       Meaning
                 
     ----------------------------------------------------------
                 
     ‘0’         The value of the registry item.
                 
                 
     ‘1’         An integer giving the registry type for
                 this value (see table in docs for
                 *note SetValueEx(): 18a6.)
                 

     Raises an *note auditing event: 1a15. ‘winreg.QueryValue’ with
     arguments ‘key’, ‘sub_key’, ‘value_name’.

 -- Function: winreg.SaveKey (key, file_name)

     Saves the specified key, and all its subkeys to the specified file.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'file_name' is the name of the file to save registry data to.  This
     file cannot already exist.  If this filename includes an extension,
     it cannot be used on file allocation table (FAT) file systems by
     the *note LoadKey(): 4435. method.

     If 'key' represents a key on a remote computer, the path described
     by 'file_name' is relative to the remote computer.  The caller of
     this method must possess the 'SeBackupPrivilege' security
     privilege.  Note that privileges are different than permissions –
     see the Conflicts Between User Rights and Permissions
     documentation(2) for more details.

     This function passes ‘NULL’ for 'security_attributes' to the API.

     Raises an *note auditing event: 1a15. ‘winreg.SaveKey’ with
     arguments ‘key’, ‘file_name’.

 -- Function: winreg.SetValue (key, sub_key, type, value)

     Associates a value with a specified key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'sub_key' is a string that names the subkey with which the value is
     associated.

     'type' is an integer that specifies the type of the data.
     Currently this must be *note REG_SZ: 4a37, meaning only strings are
     supported.  Use the *note SetValueEx(): 18a6. function for support
     for other data types.

     'value' is a string that specifies the new value.

     If the key specified by the 'sub_key' parameter does not exist, the
     SetValue function creates it.

     Value lengths are limited by available memory.  Long values (more
     than 2048 bytes) should be stored as files with the filenames
     stored in the configuration registry.  This helps the registry
     perform efficiently.

     The key identified by the 'key' parameter must have been opened
     with *note KEY_SET_VALUE: 4a38. access.

     Raises an *note auditing event: 1a15. ‘winreg.SetValue’ with
     arguments ‘key’, ‘sub_key’, ‘type’, ‘value’.

 -- Function: winreg.SetValueEx (key, value_name, reserved, type, value)

     Stores data in the value field of an open registry key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     'value_name' is a string that names the subkey with which the value
     is associated.

     'reserved' can be anything – zero is always passed to the API.

     'type' is an integer that specifies the type of the data.  See
     *note Value Types: 4a39. for the available types.

     'value' is a string that specifies the new value.

     This method can also set additional value and type information for
     the specified key.  The key identified by the key parameter must
     have been opened with *note KEY_SET_VALUE: 4a38. access.

     To open the key, use the *note CreateKey(): 4430. or *note
     OpenKey(): 4436. methods.

     Value lengths are limited by available memory.  Long values (more
     than 2048 bytes) should be stored as files with the filenames
     stored in the configuration registry.  This helps the registry
     perform efficiently.

     Raises an *note auditing event: 1a15. ‘winreg.SetValue’ with
     arguments ‘key’, ‘sub_key’, ‘type’, ‘value’.

 -- Function: winreg.DisableReflectionKey (key)

     Disables registry reflection for 32-bit processes running on a
     64-bit operating system.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     Will generally raise *note NotImplementedError: 228. if executed on
     a 32-bit operating system.

     If the key is not on the reflection list, the function succeeds but
     has no effect.  Disabling reflection for a key does not affect
     reflection of any subkeys.

     Raises an *note auditing event: 1a15. ‘winreg.DisableReflectionKey’
     with argument ‘key’.

 -- Function: winreg.EnableReflectionKey (key)

     Restores registry reflection for the specified disabled key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     Will generally raise *note NotImplementedError: 228. if executed on
     a 32-bit operating system.

     Restoring reflection for a key does not affect reflection of any
     subkeys.

     Raises an *note auditing event: 1a15. ‘winreg.EnableReflectionKey’
     with argument ‘key’.

 -- Function: winreg.QueryReflectionKey (key)

     Determines the reflection state for the specified key.

     'key' is an already open key, or one of the predefined *note HKEY_*
     constants: 4a2d.

     Returns ‘True’ if reflection is disabled.

     Will generally raise *note NotImplementedError: 228. if executed on
     a 32-bit operating system.

     Raises an *note auditing event: 1a15. ‘winreg.QueryReflectionKey’
     with argument ‘key’.

   ---------- Footnotes ----------

   (1) 
https://msdn.microsoft.com/en-us/library/ms724889%28v=VS.85%29.aspx

   (2) 
https://msdn.microsoft.com/en-us/library/ms724878%28v=VS.85%29.aspx


File: python.info,  Node: Constants<10>,  Next: Registry Handle Objects,  Prev: Functions<13>,  Up: winreg — Windows registry access

5.33.2.2 Constants
..................

The following constants are defined for use in many ‘winreg’ functions.

* Menu:

* HKEY_* Constants::
* Access Rights::
* Value Types::


File: python.info,  Node: HKEY_* Constants,  Next: Access Rights,  Up: Constants<10>

5.33.2.3 HKEY_* Constants
.........................

 -- Data: winreg.HKEY_CLASSES_ROOT

     Registry entries subordinate to this key define types (or classes)
     of documents and the properties associated with those types.  Shell
     and COM applications use the information stored under this key.

 -- Data: winreg.HKEY_CURRENT_USER

     Registry entries subordinate to this key define the preferences of
     the current user.  These preferences include the settings of
     environment variables, data about program groups, colors, printers,
     network connections, and application preferences.

 -- Data: winreg.HKEY_LOCAL_MACHINE

     Registry entries subordinate to this key define the physical state
     of the computer, including data about the bus type, system memory,
     and installed hardware and software.

 -- Data: winreg.HKEY_USERS

     Registry entries subordinate to this key define the default user
     configuration for new users on the local computer and the user
     configuration for the current user.

 -- Data: winreg.HKEY_PERFORMANCE_DATA

     Registry entries subordinate to this key allow you to access
     performance data.  The data is not actually stored in the registry;
     the registry functions cause the system to collect the data from
     its source.

 -- Data: winreg.HKEY_CURRENT_CONFIG

     Contains information about the current hardware profile of the
     local computer system.

 -- Data: winreg.HKEY_DYN_DATA

     This key is not used in versions of Windows after 98.


File: python.info,  Node: Access Rights,  Next: Value Types,  Prev: HKEY_* Constants,  Up: Constants<10>

5.33.2.4 Access Rights
......................

For more information, see Registry Key Security and Access(1).

 -- Data: winreg.KEY_ALL_ACCESS

     Combines the STANDARD_RIGHTS_REQUIRED, *note KEY_QUERY_VALUE: 4a44,
     *note KEY_SET_VALUE: 4a38, *note KEY_CREATE_SUB_KEY: 4a45, *note
     KEY_ENUMERATE_SUB_KEYS: 4a46, *note KEY_NOTIFY: 4a47, and *note
     KEY_CREATE_LINK: 4a48. access rights.

 -- Data: winreg.KEY_WRITE

     Combines the STANDARD_RIGHTS_WRITE, *note KEY_SET_VALUE: 4a38, and
     *note KEY_CREATE_SUB_KEY: 4a45. access rights.

 -- Data: winreg.KEY_READ

     Combines the STANDARD_RIGHTS_READ, *note KEY_QUERY_VALUE: 4a44,
     *note KEY_ENUMERATE_SUB_KEYS: 4a46, and *note KEY_NOTIFY: 4a47.
     values.

 -- Data: winreg.KEY_EXECUTE

     Equivalent to *note KEY_READ: 4a36.

 -- Data: winreg.KEY_QUERY_VALUE

     Required to query the values of a registry key.

 -- Data: winreg.KEY_SET_VALUE

     Required to create, delete, or set a registry value.

 -- Data: winreg.KEY_CREATE_SUB_KEY

     Required to create a subkey of a registry key.

 -- Data: winreg.KEY_ENUMERATE_SUB_KEYS

     Required to enumerate the subkeys of a registry key.

 -- Data: winreg.KEY_NOTIFY

     Required to request change notifications for a registry key or for
     subkeys of a registry key.

 -- Data: winreg.KEY_CREATE_LINK

     Reserved for system use.

* Menu:

* 64-bit Specific::

   ---------- Footnotes ----------

   (1) 
https://msdn.microsoft.com/en-us/library/ms724878%28v=VS.85%29.aspx


File: python.info,  Node: 64-bit Specific,  Up: Access Rights

5.33.2.5 64-bit Specific
........................

For more information, see Accessing an Alternate Registry View(1).

 -- Data: winreg.KEY_WOW64_64KEY

     Indicates that an application on 64-bit Windows should operate on
     the 64-bit registry view.  On 32-bit Windows, this constant is
     ignored.

 -- Data: winreg.KEY_WOW64_32KEY

     Indicates that an application on 64-bit Windows should operate on
     the 32-bit registry view.  On 32-bit Windows, this constant is
     ignored.

   ---------- Footnotes ----------

   (1) https://msdn.microsoft.com/en-us/library/aa384129(v=VS.85).aspx


File: python.info,  Node: Value Types,  Prev: Access Rights,  Up: Constants<10>

5.33.2.6 Value Types
....................

For more information, see Registry Value Types(1).

 -- Data: winreg.REG_BINARY

     Binary data in any form.

 -- Data: winreg.REG_DWORD

     32-bit number.

 -- Data: winreg.REG_DWORD_LITTLE_ENDIAN

     A 32-bit number in little-endian format.  Equivalent to *note
     REG_DWORD: 4a4f.

 -- Data: winreg.REG_DWORD_BIG_ENDIAN

     A 32-bit number in big-endian format.

 -- Data: winreg.REG_EXPAND_SZ

     Null-terminated string containing references to environment
     variables (‘%PATH%’).

 -- Data: winreg.REG_LINK

     A Unicode symbolic link.

 -- Data: winreg.REG_MULTI_SZ

     A sequence of null-terminated strings, terminated by two null
     characters.  (Python handles this termination automatically.)

 -- Data: winreg.REG_NONE

     No defined value type.

 -- Data: winreg.REG_QWORD

     A 64-bit number.

     Added in version 3.6.

 -- Data: winreg.REG_QWORD_LITTLE_ENDIAN

     A 64-bit number in little-endian format.  Equivalent to *note
     REG_QWORD: d2a.

     Added in version 3.6.

 -- Data: winreg.REG_RESOURCE_LIST

     A device-driver resource list.

 -- Data: winreg.REG_FULL_RESOURCE_DESCRIPTOR

     A hardware setting.

 -- Data: winreg.REG_RESOURCE_REQUIREMENTS_LIST

     A hardware resource list.

 -- Data: winreg.REG_SZ

     A null-terminated string.

   ---------- Footnotes ----------

   (1) 
https://msdn.microsoft.com/en-us/library/ms724884%28v=VS.85%29.aspx


File: python.info,  Node: Registry Handle Objects,  Prev: Constants<10>,  Up: winreg — Windows registry access

5.33.2.7 Registry Handle Objects
................................

This object wraps a Windows HKEY object, automatically closing it when
the object is destroyed.  To guarantee cleanup, you can call either the
*note Close(): 4a2c. method on the object, or the *note CloseKey():
4a2b. function.

All registry functions in this module return one of these objects.

All registry functions in this module which accept a handle object also
accept an integer, however, use of the handle object is encouraged.

Handle objects provide semantics for *note __bool__(): 131d. – thus

     if handle:
         print("Yes")

will print ‘Yes’ if the handle is currently valid (has not been closed
or detached).

Handle objects can be converted to an integer (e.g., using the built-in
*note int(): 257. function), in which case the underlying Windows handle
value is returned.  You can also use the *note Detach(): 4437. method to
return the integer handle, and also disconnect the Windows handle from
the handle object.

 -- Method: PyHKEY.Close ()

     Closes the underlying Windows handle.

     If the handle is already closed, no error is raised.

 -- Method: PyHKEY.Detach ()

     Detaches the Windows handle from the handle object.

     The result is an integer that holds the value of the handle before
     it is detached.  If the handle is already detached or closed, this
     will return zero.

     After calling this function, the handle is effectively invalidated,
     but the handle is not closed.  You would call this function when
     you need the underlying Win32 handle to exist beyond the lifetime
     of the handle object.

     Raises an *note auditing event: 1a15. ‘winreg.PyHKEY.Detach’ with
     argument ‘key’.

 -- Method: PyHKEY.__enter__ ()
 -- Method: PyHKEY.__exit__ (*exc_info)

     The HKEY object implements *note __enter__(): 5cb. and *note
     __exit__(): 1349. and thus supports the context protocol for the
     *note with: 5d5. statement:

          with OpenKey(HKEY_LOCAL_MACHINE, "foo") as key:
              ...  # work with key

     will automatically close 'key' when control leaves the *note with:
     5d5. block.


File: python.info,  Node: winsound — Sound-playing interface for Windows,  Prev: winreg — Windows registry access,  Up: MS Windows Specific Services

5.33.3 ‘winsound’ — Sound-playing interface for Windows
-------------------------------------------------------

__________________________________________________________________

The ‘winsound’ module provides access to the basic sound-playing
machinery provided by Windows platforms.  It includes functions and
several constants.

*note Availability: 1ef7.: Windows.

 -- Function: winsound.Beep (frequency, duration)

     Beep the PC’s speaker.  The 'frequency' parameter specifies
     frequency, in hertz, of the sound, and must be in the range 37
     through 32,767.  The 'duration' parameter specifies the number of
     milliseconds the sound should last.  If the system is not able to
     beep the speaker, *note RuntimeError: 195. is raised.

 -- Function: winsound.PlaySound (sound, flags)

     Call the underlying ‘PlaySound()’ function from the Platform API.
     The 'sound' parameter may be a filename, a system sound alias,
     audio data as a *note bytes-like object: d55, or ‘None’.  Its
     interpretation depends on the value of 'flags', which can be a
     bitwise ORed combination of the constants described below.  If the
     'sound' parameter is ‘None’, any currently playing waveform sound
     is stopped.  If the system indicates an error, *note RuntimeError:
     195. is raised.

 -- Function: winsound.MessageBeep (type=MB_OK)

     Call the underlying ‘MessageBeep()’ function from the Platform API.
     This plays a sound as specified in the registry.  The 'type'
     argument specifies which sound to play; possible values are ‘-1’,
     ‘MB_ICONASTERISK’, ‘MB_ICONEXCLAMATION’, ‘MB_ICONHAND’,
     ‘MB_ICONQUESTION’, and ‘MB_OK’, all described below.  The value
     ‘-1’ produces a “simple beep”; this is the final fallback if a
     sound cannot be played otherwise.  If the system indicates an
     error, *note RuntimeError: 195. is raised.

 -- Data: winsound.SND_FILENAME

     The 'sound' parameter is the name of a WAV file.  Do not use with
     *note SND_ALIAS: 4a5f.

 -- Data: winsound.SND_ALIAS

     The 'sound' parameter is a sound association name from the
     registry.  If the registry contains no such name, play the system
     default sound unless *note SND_NODEFAULT: 4a60. is also specified.
     If no default sound is registered, raise *note RuntimeError: 195.
     Do not use with *note SND_FILENAME: 4a5e.

     All Win32 systems support at least the following; most systems
     support many more:

     *note PlaySound(): d2e.        Corresponding Control Panel Sound name
     'name'                         

     ----------------------------------------------------------------------------
                                    
     ‘'SystemAsterisk'’             Asterisk
                                    
                                    
     ‘'SystemExclamation'’          Exclamation
                                    
                                    
     ‘'SystemExit'’                 Exit Windows
                                    
                                    
     ‘'SystemHand'’                 Critical Stop
                                    
                                    
     ‘'SystemQuestion'’             Question
                                    

     For example:

          import winsound
          # Play Windows exit sound.
          winsound.PlaySound("SystemExit", winsound.SND_ALIAS)

          # Probably play Windows default sound, if any is registered (because
          # "*" probably isn't the registered name of any sound).
          winsound.PlaySound("*", winsound.SND_ALIAS)

 -- Data: winsound.SND_LOOP

     Play the sound repeatedly.  The *note SND_ASYNC: 4a62. flag must
     also be used to avoid blocking.  Cannot be used with *note
     SND_MEMORY: 4a63.

 -- Data: winsound.SND_MEMORY

     The 'sound' parameter to *note PlaySound(): d2e. is a memory image
     of a WAV file, as a *note bytes-like object: d55.

          Note: This module does not support playing from a memory image
          asynchronously, so a combination of this flag and *note
          SND_ASYNC: 4a62. will raise *note RuntimeError: 195.

 -- Data: winsound.SND_PURGE

     Stop playing all instances of the specified sound.

          Note: This flag is not supported on modern Windows platforms.

 -- Data: winsound.SND_ASYNC

     Return immediately, allowing sounds to play asynchronously.

 -- Data: winsound.SND_NODEFAULT

     If the specified sound cannot be found, do not play the system
     default sound.

 -- Data: winsound.SND_NOSTOP

     Do not interrupt sounds currently playing.

 -- Data: winsound.SND_NOWAIT

     Return immediately if the sound driver is busy.

          Note: This flag is not supported on modern Windows platforms.

 -- Data: winsound.SND_APPLICATION

     The 'sound' parameter is an application-specific alias in the
     registry.  This flag can be combined with the *note SND_ALIAS:
     4a5f. flag to specify an application-defined sound alias.

 -- Data: winsound.MB_ICONASTERISK

     Play the ‘SystemDefault’ sound.

 -- Data: winsound.MB_ICONEXCLAMATION

     Play the ‘SystemExclamation’ sound.

 -- Data: winsound.MB_ICONHAND

     Play the ‘SystemHand’ sound.

 -- Data: winsound.MB_ICONQUESTION

     Play the ‘SystemQuestion’ sound.

 -- Data: winsound.MB_OK

     Play the ‘SystemDefault’ sound.


File: python.info,  Node: Unix-specific services,  Next: Modules command-line interface CLI,  Prev: MS Windows Specific Services,  Up: The Python Standard Library

5.34 Unix-specific services
===========================

The modules described in this chapter provide interfaces to features
that are unique to the Unix operating system, or in some cases to some
or many variants of it.  Here’s an overview:

* Menu:

* shlex — Simple lexical analysis::
* posix — The most common POSIX system calls::
* pwd — The password database::
* grp — The group database::
* termios — POSIX style tty control::
* tty — Terminal control functions::
* pty — Pseudo-terminal utilities::
* fcntl — The fcntl and ioctl system calls::
* resource — Resource usage information::
* syslog — Unix syslog library routines::


File: python.info,  Node: shlex — Simple lexical analysis,  Next: posix — The most common POSIX system calls,  Up: Unix-specific services

5.34.1 ‘shlex’ — Simple lexical analysis
----------------------------------------

'Source code:' Lib/shlex.py(1)

__________________________________________________________________

The *note shlex: cf3. class makes it easy to write lexical analyzers for
simple syntaxes resembling that of the Unix shell.  This will often be
useful for writing minilanguages, (for example, in run control files for
Python applications) or for parsing quoted strings.

The ‘shlex’ module defines the following functions:

 -- Function: shlex.split (s, comments=False, posix=True)

     Split the string 's' using shell-like syntax.  If 'comments' is
     *note False: b4f. (the default), the parsing of comments in the
     given string will be disabled (setting the *note commenters: 4a73.
     attribute of the *note shlex: cf3. instance to the empty string).
     This function operates in POSIX mode by default, but uses non-POSIX
     mode if the 'posix' argument is false.

     Changed in version 3.12: Passing ‘None’ for 's' argument now raises
     an exception, rather than reading *note sys.stdin: 540.

 -- Function: shlex.join (split_command)

     Concatenate the tokens of the list 'split_command' and return a
     string.  This function is the inverse of *note split(): 53f.

          >>> from shlex import join
          >>> print(join(['echo', '-n', 'Multiple words']))
          echo -n 'Multiple words'

     The returned value is shell-escaped to protect against injection
     vulnerabilities (see *note quote(): 27d.).

     Added in version 3.8.

 -- Function: shlex.quote (s)

     Return a shell-escaped version of the string 's'.  The returned
     value is a string that can safely be used as one token in a shell
     command line, for cases where you cannot use a list.
          Warning: The ‘shlex’ module is 'only designed for Unix
          shells'.

          The ‘quote()’ function is not guaranteed to be correct on
          non-POSIX compliant shells or shells from other operating
          systems such as Windows.  Executing commands quoted by this
          module on such shells can open up the possibility of a command
          injection vulnerability.

          Consider using functions that pass command arguments with
          lists such as *note subprocess.run(): ba4. with ‘shell=False’.

     This idiom would be unsafe:

          >>> filename = 'somefile; rm -rf ~'
          >>> command = 'ls -l {}'.format(filename)
          >>> print(command)  # executed by a shell: boom!
          ls -l somefile; rm -rf ~

     ‘quote()’ lets you plug the security hole:

          >>> from shlex import quote
          >>> command = 'ls -l {}'.format(quote(filename))
          >>> print(command)
          ls -l 'somefile; rm -rf ~'
          >>> remote_command = 'ssh home {}'.format(quote(command))
          >>> print(remote_command)
          ssh home 'ls -l '"'"'somefile; rm -rf ~'"'"''

     The quoting is compatible with UNIX shells and with *note split():
     53f.:

          >>> from shlex import split
          >>> remote_command = split(remote_command)
          >>> remote_command
          ['ssh', 'home', "ls -l 'somefile; rm -rf ~'"]
          >>> command = split(remote_command[-1])
          >>> command
          ['ls', '-l', 'somefile; rm -rf ~']

     Added in version 3.3.

The ‘shlex’ module defines the following class:

 -- Class: shlex.shlex (instream=None, infile=None, posix=False,
          punctuation_chars=False)

     A *note shlex: cf3. instance or subclass instance is a lexical
     analyzer object.  The initialization argument, if present,
     specifies where to read characters from.  It must be a
     file-/stream-like object with *note read(): 1e24. and *note
     readline(): 1e5e. methods, or a string.  If no argument is given,
     input will be taken from ‘sys.stdin’.  The second optional argument
     is a filename string, which sets the initial value of the *note
     infile: 4a74. attribute.  If the 'instream' argument is omitted or
     equal to ‘sys.stdin’, this second argument defaults to “stdin”.
     The 'posix' argument defines the operational mode: when 'posix' is
     not true (default), the ‘shlex’ instance will operate in
     compatibility mode.  When operating in POSIX mode, ‘shlex’ will try
     to be as close as possible to the POSIX shell parsing rules.  The
     'punctuation_chars' argument provides a way to make the behaviour
     even closer to how real shells parse.  This can take a number of
     values: the default value, ‘False’, preserves the behaviour seen
     under Python 3.5 and earlier.  If set to ‘True’, then parsing of
     the characters ‘();<>|&’ is changed: any run of these characters
     (considered punctuation characters) is returned as a single token.
     If set to a non-empty string of characters, those characters will
     be used as the punctuation characters.  Any characters in the *note
     wordchars: 4a75. attribute that appear in 'punctuation_chars' will
     be removed from ‘wordchars’.  See *note Improved Compatibility with
     Shells: cf4. for more information.  'punctuation_chars' can be set
     only upon ‘shlex’ instance creation and can’t be modified later.

     Changed in version 3.6: The 'punctuation_chars' parameter was
     added.

See also
........

Module *note configparser: 22.

     Parser for configuration files similar to the Windows ‘.ini’ files.

* Menu:

* shlex Objects::
* Parsing Rules::
* Improved Compatibility with Shells::

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/shlex.py


File: python.info,  Node: shlex Objects,  Next: Parsing Rules,  Up: shlex — Simple lexical analysis

5.34.1.1 shlex Objects
......................

A *note shlex: cf3. instance has the following methods:

 -- Method: shlex.get_token ()

     Return a token.  If tokens have been stacked using *note
     push_token(): 4a79, pop a token off the stack.  Otherwise, read one
     from the input stream.  If reading encounters an immediate
     end-of-file, *note eof: 4a7a. is returned (the empty string (‘''’)
     in non-POSIX mode, and ‘None’ in POSIX mode).

 -- Method: shlex.push_token (str)

     Push the argument onto the token stack.

 -- Method: shlex.read_token ()

     Read a raw token.  Ignore the pushback stack, and do not interpret
     source requests.  (This is not ordinarily a useful entry point, and
     is documented here only for the sake of completeness.)

 -- Method: shlex.sourcehook (filename)

     When *note shlex: cf3. detects a source request (see *note source:
     4a7d. below) this method is given the following token as argument,
     and expected to return a tuple consisting of a filename and an open
     file-like object.

     Normally, this method first strips any quotes off the argument.  If
     the result is an absolute pathname, or there was no previous source
     request in effect, or the previous source was a stream (such as
     ‘sys.stdin’), the result is left alone.  Otherwise, if the result
     is a relative pathname, the directory part of the name of the file
     immediately before it on the source inclusion stack is prepended
     (this behavior is like the way the C preprocessor handles ‘#include
     "file.h"’).

     The result of the manipulations is treated as a filename, and
     returned as the first component of the tuple, with *note open():
     51f. called on it to yield the second component.  (Note: this is
     the reverse of the order of arguments in instance initialization!)

     This hook is exposed so that you can use it to implement directory
     search paths, addition of file extensions, and other namespace
     hacks.  There is no corresponding ‘close’ hook, but a shlex
     instance will call the *note close(): 1f6. method of the sourced
     input stream when it returns EOF.

     For more explicit control of source stacking, use the *note
     push_source(): 4a7e. and *note pop_source(): 4a7f. methods.

 -- Method: shlex.push_source (newstream, newfile=None)

     Push an input source stream onto the input stack.  If the filename
     argument is specified it will later be available for use in error
     messages.  This is the same method used internally by the *note
     sourcehook(): 4a7c. method.

 -- Method: shlex.pop_source ()

     Pop the last-pushed input source from the input stack.  This is the
     same method used internally when the lexer reaches EOF on a stacked
     input stream.

 -- Method: shlex.error_leader (infile=None, lineno=None)

     This method generates an error message leader in the format of a
     Unix C compiler error label; the format is ‘'"%s", line %d: '’,
     where the ‘%s’ is replaced with the name of the current source file
     and the ‘%d’ with the current input line number (the optional
     arguments can be used to override these).

     This convenience is provided to encourage ‘shlex’ users to generate
     error messages in the standard, parseable format understood by
     Emacs and other Unix tools.

Instances of *note shlex: cf3. subclasses have some public instance
variables which either control lexical analysis or can be used for
debugging:

 -- Attribute: shlex.commenters

     The string of characters that are recognized as comment beginners.
     All characters from the comment beginner to end of line are
     ignored.  Includes just ‘'#'’ by default.

 -- Attribute: shlex.wordchars

     The string of characters that will accumulate into multi-character
     tokens.  By default, includes all ASCII alphanumerics and
     underscore.  In POSIX mode, the accented characters in the Latin-1
     set are also included.  If *note punctuation_chars: 1b61. is not
     empty, the characters ‘~-./*?=’, which can appear in filename
     specifications and command line parameters, will also be included
     in this attribute, and any characters which appear in
     ‘punctuation_chars’ will be removed from ‘wordchars’ if they are
     present there.  If *note whitespace_split: 4a81. is set to ‘True’,
     this will have no effect.

 -- Attribute: shlex.whitespace

     Characters that will be considered whitespace and skipped.
     Whitespace bounds tokens.  By default, includes space, tab,
     linefeed and carriage-return.

 -- Attribute: shlex.escape

     Characters that will be considered as escape.  This will be only
     used in POSIX mode, and includes just ‘'\'’ by default.

 -- Attribute: shlex.quotes

     Characters that will be considered string quotes.  The token
     accumulates until the same quote is encountered again (thus,
     different quote types protect each other as in the shell.)  By
     default, includes ASCII single and double quotes.

 -- Attribute: shlex.escapedquotes

     Characters in *note quotes: 4a84. that will interpret escape
     characters defined in *note escape: 4a83.  This is only used in
     POSIX mode, and includes just ‘'"'’ by default.

 -- Attribute: shlex.whitespace_split

     If ‘True’, tokens will only be split in whitespaces.  This is
     useful, for example, for parsing command lines with *note shlex:
     cf3, getting tokens in a similar way to shell arguments.  When used
     in combination with *note punctuation_chars: 1b61, tokens will be
     split on whitespace in addition to those characters.

     Changed in version 3.8: The *note punctuation_chars: 1b61.
     attribute was made compatible with the *note whitespace_split:
     4a81. attribute.

 -- Attribute: shlex.infile

     The name of the current input file, as initially set at class
     instantiation time or stacked by later source requests.  It may be
     useful to examine this when constructing error messages.

 -- Attribute: shlex.instream

     The input stream from which this *note shlex: cf3. instance is
     reading characters.

 -- Attribute: shlex.source

     This attribute is ‘None’ by default.  If you assign a string to it,
     that string will be recognized as a lexical-level inclusion request
     similar to the ‘source’ keyword in various shells.  That is, the
     immediately following token will be opened as a filename and input
     will be taken from that stream until EOF, at which point the *note
     close(): 1f6. method of that stream will be called and the input
     source will again become the original input stream.  Source
     requests may be stacked any number of levels deep.

 -- Attribute: shlex.debug

     If this attribute is numeric and ‘1’ or more, a *note shlex: cf3.
     instance will print verbose progress output on its behavior.  If
     you need to use this, you can read the module source code to learn
     the details.

 -- Attribute: shlex.lineno

     Source line number (count of newlines seen so far plus one).

 -- Attribute: shlex.token

     The token buffer.  It may be useful to examine this when catching
     exceptions.

 -- Attribute: shlex.eof

     Token used to determine end of file.  This will be set to the empty
     string (‘''’), in non-POSIX mode, and to ‘None’ in POSIX mode.

 -- Attribute: shlex.punctuation_chars

     A read-only property.  Characters that will be considered
     punctuation.  Runs of punctuation characters will be returned as a
     single token.  However, note that no semantic validity checking
     will be performed: for example, ‘>>>’ could be returned as a token,
     even though it may not be recognised as such by shells.

     Added in version 3.6.


File: python.info,  Node: Parsing Rules,  Next: Improved Compatibility with Shells,  Prev: shlex Objects,  Up: shlex — Simple lexical analysis

5.34.1.2 Parsing Rules
......................

When operating in non-POSIX mode, *note shlex: cf3. will try to obey the
following rules.

   * Quote characters are not recognized within words (‘Do"Not"Separate’
     is parsed as the single word ‘Do"Not"Separate’);

   * Escape characters are not recognized;

   * Enclosing characters in quotes preserve the literal value of all
     characters within the quotes;

   * Closing quotes separate words (‘"Do"Separate’ is parsed as ‘"Do"’
     and ‘Separate’);

   * If *note whitespace_split: 4a81. is ‘False’, any character not
     declared to be a word character, whitespace, or a quote will be
     returned as a single-character token.  If it is ‘True’, *note
     shlex: cf3. will only split words in whitespaces;

   * EOF is signaled with an empty string (‘''’);

   * It’s not possible to parse empty strings, even if quoted.

When operating in POSIX mode, *note shlex: cf3. will try to obey the
following parsing rules.

   * Quotes are stripped out, and do not separate words
     (‘"Do"Not"Separate"’ is parsed as the single word ‘DoNotSeparate’);

   * Non-quoted escape characters (e.g.  ‘'\'’) preserve the literal
     value of the next character that follows;

   * Enclosing characters in quotes which are not part of *note
     escapedquotes: 4a85. (e.g.  ‘"'"’)  preserve the literal value of
     all characters within the quotes;

   * Enclosing characters in quotes which are part of *note
     escapedquotes: 4a85. (e.g.  ‘'"'’)  preserves the literal value of
     all characters within the quotes, with the exception of the
     characters mentioned in *note escape: 4a83.  The escape characters
     retain their special meaning only when followed by the quote in
     use, or the escape character itself.  Otherwise the escape
     character will be considered a normal character.

   * EOF is signaled with a *note None: 678. value;

   * Quoted empty strings (‘''’) are allowed.


File: python.info,  Node: Improved Compatibility with Shells,  Prev: Parsing Rules,  Up: shlex — Simple lexical analysis

5.34.1.3 Improved Compatibility with Shells
...........................................

Added in version 3.6.

The *note shlex: c4. class provides compatibility with the parsing
performed by common Unix shells like ‘bash’, ‘dash’, and ‘sh’.  To take
advantage of this compatibility, specify the ‘punctuation_chars’
argument in the constructor.  This defaults to ‘False’, which preserves
pre-3.6 behaviour.  However, if it is set to ‘True’, then parsing of the
characters ‘();<>|&’ is changed: any run of these characters is returned
as a single token.  While this is short of a full parser for shells
(which would be out of scope for the standard library, given the
multiplicity of shells out there), it does allow you to perform
processing of command lines more easily than you could otherwise.  To
illustrate, you can see the difference in the following snippet:

     >>> import shlex
     >>> text = "a && b; c && d || e; f >'abc'; (def \"ghi\")"
     >>> s = shlex.shlex(text, posix=True)
     >>> s.whitespace_split = True
     >>> list(s)
     ['a', '&&', 'b;', 'c', '&&', 'd', '||', 'e;', 'f', '>abc;', '(def', 'ghi)']
     >>> s = shlex.shlex(text, posix=True, punctuation_chars=True)
     >>> s.whitespace_split = True
     >>> list(s)
     ['a', '&&', 'b', ';', 'c', '&&', 'd', '||', 'e', ';', 'f', '>', 'abc', ';',
     '(', 'def', 'ghi', ')']

Of course, tokens will be returned which are not valid for shells, and
you’ll need to implement your own error checks on the returned tokens.

Instead of passing ‘True’ as the value for the punctuation_chars
parameter, you can pass a string with specific characters, which will be
used to determine which characters constitute punctuation.  For example:

     >>> import shlex
     >>> s = shlex.shlex("a && b || c", punctuation_chars="|")
     >>> list(s)
     ['a', '&', '&', 'b', '||', 'c']

     Note: When ‘punctuation_chars’ is specified, the *note wordchars:
     4a75. attribute is augmented with the characters ‘~-./*?=’.  That
     is because these characters can appear in file names (including
     wildcards) and command-line arguments (e.g.  ‘--color=auto’).
     Hence:

          >>> import shlex
          >>> s = shlex.shlex('~/a && b-c --color=auto || d *.py?',
          ...                 punctuation_chars=True)
          >>> list(s)
          ['~/a', '&&', 'b-c', '--color=auto', '||', 'd', '*.py?']

     However, to match the shell as closely as possible, it is
     recommended to always use ‘posix’ and *note whitespace_split: 4a81.
     when using *note punctuation_chars: 1b61, which will negate *note
     wordchars: 4a75. entirely.

For best effect, ‘punctuation_chars’ should be set in conjunction with
‘posix=True’.  (Note that ‘posix=False’ is the default for *note shlex:
cf3.)


File: python.info,  Node: posix — The most common POSIX system calls,  Next: pwd — The password database,  Prev: shlex — Simple lexical analysis,  Up: Unix-specific services

5.34.2 ‘posix’ — The most common POSIX system calls
---------------------------------------------------

__________________________________________________________________

This module provides access to operating system functionality that is
standardized by the C Standard and the POSIX standard (a thinly
disguised Unix interface).

*note Availability: 1ef7.: Unix.

'Do not import this module directly.'  Instead, import the module *note
os: a1, which provides a 'portable' version of this interface.  On Unix,
the ‘os’ module provides a superset of the ‘posix’ interface.  On
non-Unix operating systems the ‘posix’ module is not available, but a
subset is always available through the ‘os’ interface.  Once ‘os’ is
imported, there is 'no' performance penalty in using it instead of
‘posix’.  In addition, ‘os’ provides some additional functionality, such
as automatically calling *note putenv(): 925. when an entry in
‘os.environ’ is changed.

Errors are reported as exceptions; the usual exceptions are given for
type errors, while errors reported by the system calls raise *note
OSError: 41a.

* Menu:

* Large File Support::
* Notable Module Contents::


File: python.info,  Node: Large File Support,  Next: Notable Module Contents,  Up: posix — The most common POSIX system calls

5.34.2.1 Large File Support
...........................

Several operating systems (including AIX and Solaris) provide support
for files that are larger than 2 GiB from a C programming model where
int and long are 32-bit values.  This is typically accomplished by
defining the relevant size and offset types as 64-bit values.  Such
files are sometimes referred to as 'large files'.

Large file support is enabled in Python when the size of an ‘off_t’ is
larger than a long and the long long is at least as large as an ‘off_t’.
It may be necessary to configure and compile Python with certain
compiler flags to enable this mode.  For example, with Solaris 2.6 and
2.7 you need to do something like:

     CFLAGS="`getconf LFS_CFLAGS`" OPT="-g -O2 $CFLAGS" \
             ./configure

On large-file-capable Linux systems, this might work:

     CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \
             ./configure


File: python.info,  Node: Notable Module Contents,  Prev: Large File Support,  Up: posix — The most common POSIX system calls

5.34.2.2 Notable Module Contents
................................

In addition to many functions described in the *note os: a1. module
documentation, ‘posix’ defines the following data item:

 -- Data: posix.environ

     A dictionary representing the string environment at the time the
     interpreter was started.  Keys and values are bytes on Unix and str
     on Windows.  For example, ‘environ[b'HOME']’ (‘environ['HOME']’ on
     Windows) is the pathname of your home directory, equivalent to
     ‘getenv("HOME")’ in C.

     Modifying this dictionary does not affect the string environment
     passed on by *note execv(): 2d16, *note popen(): a96. or *note
     system(): 14ac.; if you need to change the environment, pass
     ‘environ’ to *note execve(): 113d. or add variable assignments and
     export statements to the command string for ‘system()’ or
     ‘popen()’.

     Changed in version 3.2: On Unix, keys and values are bytes.

          Note: The *note os: a1. module provides an alternate
          implementation of ‘environ’ which updates the environment on
          modification.  Note also that updating *note os.environ: 11fe.
          will render this dictionary obsolete.  Use of the ‘os’ module
          version of this is recommended over direct access to the
          ‘posix’ module.


File: python.info,  Node: pwd — The password database,  Next: grp — The group database,  Prev: posix — The most common POSIX system calls,  Up: Unix-specific services

5.34.3 ‘pwd’ — The password database
------------------------------------

__________________________________________________________________

This module provides access to the Unix user account and password
database.  It is available on all Unix versions.

*note Availability: 1ef7.: Unix, not WASI, not iOS.

Password database entries are reported as a tuple-like object, whose
attributes correspond to the members of the ‘passwd’ structure
(Attribute field below, see ‘<pwd.h>’):

Index       Attribute           Meaning
                                
------------------------------------------------------------------
                                
0           ‘pw_name’           Login name
                                
                                
1           ‘pw_passwd’         Optional encrypted password
                                
                                
2           ‘pw_uid’            Numerical user ID
                                
                                
3           ‘pw_gid’            Numerical group ID
                                
                                
4           ‘pw_gecos’          User name or comment field
                                
                                
5           ‘pw_dir’            User home directory
                                
                                
6           ‘pw_shell’          User command interpreter
                                

The uid and gid items are integers, all others are strings.  *note
KeyError: 345. is raised if the entry asked for cannot be found.

     Note: In traditional Unix the field ‘pw_passwd’ usually contains a
     password encrypted with a DES derived algorithm.  However most
     modern unices use a so-called 'shadow password' system.  On those
     unices the 'pw_passwd' field only contains an asterisk (‘'*'’) or
     the letter ‘'x'’ where the encrypted password is stored in a file
     ‘/etc/shadow’ which is not world readable.  Whether the 'pw_passwd'
     field contains anything useful is system-dependent.

It defines the following items:

 -- Function: pwd.getpwuid (uid)

     Return the password database entry for the given numeric user ID.

 -- Function: pwd.getpwnam (name)

     Return the password database entry for the given user name.

 -- Function: pwd.getpwall ()

     Return a list of all available password database entries, in
     arbitrary order.

See also
........

Module *note grp: 66.

     An interface to the group database, similar to this.


File: python.info,  Node: grp — The group database,  Next: termios — POSIX style tty control,  Prev: pwd — The password database,  Up: Unix-specific services

5.34.4 ‘grp’ — The group database
---------------------------------

__________________________________________________________________

This module provides access to the Unix group database.  It is available
on all Unix versions.

*note Availability: 1ef7.: Unix, not WASI, not Android, not iOS.

Group database entries are reported as a tuple-like object, whose
attributes correspond to the members of the ‘group’ structure (Attribute
field below, see ‘<grp.h>’):

Index       Attribute       Meaning
                            
------------------------------------------------------------------
                            
0           gr_name         the name of the group
                            
                            
1           gr_passwd       the (encrypted) group password;
                            often empty
                            
                            
2           gr_gid          the numerical group ID
                            
                            
3           gr_mem          all the group member’s user names
                            

The gid is an integer, name and password are strings, and the member
list is a list of strings.  (Note that most users are not explicitly
listed as members of the group they are in according to the password
database.  Check both databases to get complete membership information.
Also note that a ‘gr_name’ that starts with a ‘+’ or ‘-’ is likely to be
a YP/NIS reference and may not be accessible via *note getgrnam(): 3416.
or *note getgrgid(): d4e.)

It defines the following items:

 -- Function: grp.getgrgid (id)

     Return the group database entry for the given numeric group ID.
     *note KeyError: 345. is raised if the entry asked for cannot be
     found.

     Changed in version 3.10: *note TypeError: 2c3. is raised for
     non-integer arguments like floats or strings.

 -- Function: grp.getgrnam (name)

     Return the group database entry for the given group name.  *note
     KeyError: 345. is raised if the entry asked for cannot be found.

 -- Function: grp.getgrall ()

     Return a list of all available group entries, in arbitrary order.

See also
........

Module *note pwd: b2.

     An interface to the user database, similar to this.


File: python.info,  Node: termios — POSIX style tty control,  Next: tty — Terminal control functions,  Prev: grp — The group database,  Up: Unix-specific services

5.34.5 ‘termios’ — POSIX style tty control
------------------------------------------

__________________________________________________________________

This module provides an interface to the POSIX calls for tty I/O
control.  For a complete description of these calls, see ‘termios(3)(1)’
Unix manual page.  It is only available for those Unix versions that
support POSIX 'termios' style tty I/O control configured during
installation.

*note Availability: 1ef7.: Unix.

All functions in this module take a file descriptor 'fd' as their first
argument.  This can be an integer file descriptor, such as returned by
‘sys.stdin.fileno()’, or a *note file object: 1208, such as ‘sys.stdin’
itself.

This module also defines all the constants needed to work with the
functions provided here; these have the same name as their counterparts
in C. Please refer to your system documentation for more information on
using these terminal control interfaces.

The module defines the following functions:

 -- Function: termios.tcgetattr (fd)

     Return a list containing the tty attributes for file descriptor
     'fd', as follows: ‘[iflag, oflag, cflag, lflag, ispeed, ospeed,
     cc]’ where 'cc' is a list of the tty special characters (each a
     string of length 1, except the items with indices ‘VMIN’ and
     ‘VTIME’, which are integers when these fields are defined).  The
     interpretation of the flags and the speeds as well as the indexing
     in the 'cc' array must be done using the symbolic constants defined
     in the ‘termios’ module.

 -- Function: termios.tcsetattr (fd, when, attributes)

     Set the tty attributes for file descriptor 'fd' from the
     'attributes', which is a list like the one returned by *note
     tcgetattr(): 1789.  The 'when' argument determines when the
     attributes are changed:

      -- Data: termios.TCSANOW

          Change attributes immediately.

      -- Data: termios.TCSADRAIN

          Change attributes after transmitting all queued output.

      -- Data: termios.TCSAFLUSH

          Change attributes after transmitting all queued output and
          discarding all queued input.

 -- Function: termios.tcsendbreak (fd, duration)

     Send a break on file descriptor 'fd'.  A zero 'duration' sends a
     break for 0.25–0.5 seconds; a nonzero 'duration' has a system
     dependent meaning.

 -- Function: termios.tcdrain (fd)

     Wait until all output written to file descriptor 'fd' has been
     transmitted.

 -- Function: termios.tcflush (fd, queue)

     Discard queued data on file descriptor 'fd'.  The 'queue' selector
     specifies which queue: ‘TCIFLUSH’ for the input queue, ‘TCOFLUSH’
     for the output queue, or ‘TCIOFLUSH’ for both queues.

 -- Function: termios.tcflow (fd, action)

     Suspend or resume input or output on file descriptor 'fd'.  The
     'action' argument can be ‘TCOOFF’ to suspend output, ‘TCOON’ to
     restart output, ‘TCIOFF’ to suspend input, or ‘TCION’ to restart
     input.

 -- Function: termios.tcgetwinsize (fd)

     Return a tuple ‘(ws_row, ws_col)’ containing the tty window size
     for file descriptor 'fd'.  Requires ‘termios.TIOCGWINSZ’ or
     ‘termios.TIOCGSIZE’.

     Added in version 3.11.

 -- Function: termios.tcsetwinsize (fd, winsize)

     Set the tty window size for file descriptor 'fd' from 'winsize',
     which is a two-item tuple ‘(ws_row, ws_col)’ like the one returned
     by *note tcgetwinsize(): 4aa6.  Requires at least one of the pairs
     (‘termios.TIOCGWINSZ’, ‘termios.TIOCSWINSZ’); (‘termios.TIOCGSIZE’,
     ‘termios.TIOCSSIZE’) to be defined.

     Added in version 3.11.

See also
........

Module *note tty: 100.

     Convenience functions for common terminal control operations.

* Menu:

* Example: Example<15>.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/termios(3)


File: python.info,  Node: Example<15>,  Up: termios — POSIX style tty control

5.34.5.1 Example
................

Here’s a function that prompts for a password with echoing turned off.
Note the technique using a separate *note tcgetattr(): 1789. call and a
*note try: 6ec. … *note finally: 9d5. statement to ensure that the old
tty attributes are restored exactly no matter what happens:

     def getpass(prompt="Password: "):
         import termios, sys
         fd = sys.stdin.fileno()
         old = termios.tcgetattr(fd)
         new = termios.tcgetattr(fd)
         new[3] = new[3] & ~termios.ECHO          # lflags
         try:
             termios.tcsetattr(fd, termios.TCSADRAIN, new)
             passwd = input(prompt)
         finally:
             termios.tcsetattr(fd, termios.TCSADRAIN, old)
         return passwd


File: python.info,  Node: tty — Terminal control functions,  Next: pty — Pseudo-terminal utilities,  Prev: termios — POSIX style tty control,  Up: Unix-specific services

5.34.6 ‘tty’ — Terminal control functions
-----------------------------------------

'Source code:' Lib/tty.py(1)

__________________________________________________________________

The ‘tty’ module defines functions for putting the tty into cbreak and
raw modes.

*note Availability: 1ef7.: Unix.

Because it requires the *note termios: e1. module, it will work only on
Unix.

The ‘tty’ module defines the following functions:

 -- Function: tty.cfmakeraw (mode)

     Convert the tty attribute list 'mode', which is a list like the one
     returned by *note termios.tcgetattr(): 1789, to that of a tty in
     raw mode.

     Added in version 3.12.

 -- Function: tty.cfmakecbreak (mode)

     Convert the tty attribute list 'mode', which is a list like the one
     returned by *note termios.tcgetattr(): 1789, to that of a tty in
     cbreak mode.

     This clears the ‘ECHO’ and ‘ICANON’ local mode flags in 'mode' as
     well as setting the minimum input to 1 byte with no delay.

     Added in version 3.12.

     Changed in version 3.12.2: The ‘ICRNL’ flag is no longer cleared.
     This matches Linux and macOS ‘stty cbreak’ behavior and what *note
     setcbreak(): 178b. historically did.

 -- Function: tty.setraw (fd, when=termios.TCSAFLUSH)

     Change the mode of the file descriptor 'fd' to raw.  If 'when' is
     omitted, it defaults to *note termios.TCSAFLUSH: 4aa1, and is
     passed to *note termios.tcsetattr(): 1808.  The return value of
     *note termios.tcgetattr(): 1789. is saved before setting 'fd' to
     raw mode; this value is returned.

     Changed in version 3.12: The return value is now the original tty
     attributes, instead of ‘None’.

 -- Function: tty.setcbreak (fd, when=termios.TCSAFLUSH)

     Change the mode of file descriptor 'fd' to cbreak.  If 'when' is
     omitted, it defaults to *note termios.TCSAFLUSH: 4aa1, and is
     passed to *note termios.tcsetattr(): 1808.  The return value of
     *note termios.tcgetattr(): 1789. is saved before setting 'fd' to
     cbreak mode; this value is returned.

     This clears the ‘ECHO’ and ‘ICANON’ local mode flags as well as
     setting the minimum input to 1 byte with no delay.

     Changed in version 3.12: The return value is now the original tty
     attributes, instead of ‘None’.

     Changed in version 3.12.2: The ‘ICRNL’ flag is no longer cleared.
     This restores the behavior of Python 3.11 and earlier as well as
     matching what Linux, macOS, & BSDs describe in their ‘stty(1)’ man
     pages regarding cbreak mode.

See also
........

Module *note termios: e1.

     Low-level terminal control interface.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/tty.py


File: python.info,  Node: pty — Pseudo-terminal utilities,  Next: fcntl — The fcntl and ioctl system calls,  Prev: tty — Terminal control functions,  Up: Unix-specific services

5.34.7 ‘pty’ — Pseudo-terminal utilities
----------------------------------------

'Source code:' Lib/pty.py(1)

__________________________________________________________________

The ‘pty’ module defines operations for handling the pseudo-terminal
concept: starting another process and being able to write to and read
from its controlling terminal programmatically.

*note Availability: 1ef7.: Unix.

Pseudo-terminal handling is highly platform dependent.  This code is
mainly tested on Linux, FreeBSD, and macOS (it is supposed to work on
other POSIX platforms but it’s not been thoroughly tested).

The ‘pty’ module defines the following functions:

 -- Function: pty.fork ()

     Fork.  Connect the child’s controlling terminal to a
     pseudo-terminal.  Return value is ‘(pid, fd)’.  Note that the child
     gets 'pid' 0, and the 'fd' is 'invalid'.  The parent’s return value
     is the 'pid' of the child, and 'fd' is a file descriptor connected
     to the child’s controlling terminal (and also to the child’s
     standard input and output).

          Warning: On macOS the use of this function is unsafe when
          mixed with using higher-level system APIs, and that includes
          using *note urllib.request: 10b.

 -- Function: pty.openpty ()

     Open a new pseudo-terminal pair, using *note os.openpty(): 2d58. if
     possible, or emulation code for generic Unix systems.  Return a
     pair of file descriptors ‘(master, slave)’, for the master and the
     slave end, respectively.

 -- Function: pty.spawn (argv[, master_read[, stdin_read]])

     Spawn a process, and connect its controlling terminal with the
     current process’s standard io.  This is often used to baffle
     programs which insist on reading from the controlling terminal.  It
     is expected that the process spawned behind the pty will eventually
     terminate, and when it does 'spawn' will return.

     A loop copies STDIN of the current process to the child and data
     received from the child to STDOUT of the current process.  It is
     not signaled to the child if STDIN of the current process closes
     down.

     The functions 'master_read' and 'stdin_read' are passed a file
     descriptor which they should read from, and they should always
     return a byte string.  In order to force spawn to return before the
     child process exits an empty byte array should be returned to
     signal end of file.

     The default implementation for both functions will read and return
     up to 1024 bytes each time the function is called.  The
     'master_read' callback is passed the pseudoterminal’s master file
     descriptor to read output from the child process, and 'stdin_read'
     is passed file descriptor 0, to read from the parent process’s
     standard input.

     Returning an empty byte string from either callback is interpreted
     as an end-of-file (EOF) condition, and that callback will not be
     called after that.  If 'stdin_read' signals EOF the controlling
     terminal can no longer communicate with the parent process OR the
     child process.  Unless the child process will quit without any
     input, 'spawn' will then loop forever.  If 'master_read' signals
     EOF the same behavior results (on linux at least).

     Return the exit status value from *note os.waitpid(): dc8. on the
     child process.

     *note os.waitstatus_to_exitcode(): 926. can be used to convert the
     exit status into an exit code.

     Raises an *note auditing event: 1a15. ‘pty.spawn’ with argument
     ‘argv’.

     Changed in version 3.4: ‘spawn()’ now returns the status value from
     *note os.waitpid(): dc8. on the child process.

* Menu:

* Example: Example<16>.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/pty.py


File: python.info,  Node: Example<16>,  Up: pty — Pseudo-terminal utilities

5.34.7.1 Example
................

The following program acts like the Unix command ‘script(1)(1)’, using a
pseudo-terminal to record all input and output of a terminal session in
a “typescript”.

     import argparse
     import os
     import pty
     import sys
     import time

     parser = argparse.ArgumentParser()
     parser.add_argument('-a', dest='append', action='store_true')
     parser.add_argument('-p', dest='use_python', action='store_true')
     parser.add_argument('filename', nargs='?', default='typescript')
     options = parser.parse_args()

     shell = sys.executable if options.use_python else os.environ.get('SHELL', 'sh')
     filename = options.filename
     mode = 'ab' if options.append else 'wb'

     with open(filename, mode) as script:
         def read(fd):
             data = os.read(fd, 1024)
             script.write(data)
             return data

         print('Script started, file is', filename)
         script.write(('Script started on %s\n' % time.asctime()).encode())

         pty.spawn(shell, read)

         script.write(('Script done on %s\n' % time.asctime()).encode())
         print('Script done, file is', filename)

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/script(1)


File: python.info,  Node: fcntl — The fcntl and ioctl system calls,  Next: resource — Resource usage information,  Prev: pty — Pseudo-terminal utilities,  Up: Unix-specific services

5.34.8 ‘fcntl’ — The ‘fcntl’ and ‘ioctl’ system calls
-----------------------------------------------------

__________________________________________________________________

This module performs file and I/O control on file descriptors.  It is an
interface to the ‘fcntl()’ and ‘ioctl()’ Unix routines.  See the
‘fcntl(2)(1)’ and ‘ioctl(2)(2)’ Unix manual pages for full details.

*note Availability: 1ef7.: Unix, not WASI.

All functions in this module take a file descriptor 'fd' as their first
argument.  This can be an integer file descriptor, such as returned by
‘sys.stdin.fileno()’, or an *note io.IOBase: 1f5. object, such as
‘sys.stdin’ itself, which provides a *note fileno(): 15f5. that returns
a genuine file descriptor.

Changed in version 3.3: Operations in this module used to raise an *note
IOError: 1090. where they now raise an *note OSError: 41a.

Changed in version 3.8: The ‘fcntl’ module now contains ‘F_ADD_SEALS’,
‘F_GET_SEALS’, and ‘F_SEAL_*’ constants for sealing of *note
os.memfd_create(): a16. file descriptors.

Changed in version 3.9: On macOS, the ‘fcntl’ module exposes the
‘F_GETPATH’ constant, which obtains the path of a file from a file
descriptor.  On Linux(>=3.15), the ‘fcntl’ module exposes the
‘F_OFD_GETLK’, ‘F_OFD_SETLK’ and ‘F_OFD_SETLKW’ constants, which are
used when working with open file description locks.

Changed in version 3.10: On Linux >= 2.6.11, the ‘fcntl’ module exposes
the ‘F_GETPIPE_SZ’ and ‘F_SETPIPE_SZ’ constants, which allow to check
and modify a pipe’s size respectively.

Changed in version 3.11: On FreeBSD, the ‘fcntl’ module exposes the
‘F_DUP2FD’ and ‘F_DUP2FD_CLOEXEC’ constants, which allow to duplicate a
file descriptor, the latter setting ‘FD_CLOEXEC’ flag in addition.

Changed in version 3.12: On Linux >= 4.5, the ‘fcntl’ module exposes the
‘FICLONE’ and ‘FICLONERANGE’ constants, which allow to share some data
of one file with another file by reflinking on some filesystems (e.g.,
btrfs, OCFS2, and XFS). This behavior is commonly referred to as
“copy-on-write”.

Changed in version 3.13: On Linux >= 2.6.32, the ‘fcntl’ module exposes
the ‘F_GETOWN_EX’, ‘F_SETOWN_EX’, ‘F_OWNER_TID’, ‘F_OWNER_PID’,
‘F_OWNER_PGRP’ constants, which allow to direct I/O availability signals
to a specific thread, process, or process group.  On Linux >= 4.13, the
‘fcntl’ module exposes the ‘F_GET_RW_HINT’, ‘F_SET_RW_HINT’,
‘F_GET_FILE_RW_HINT’, ‘F_SET_FILE_RW_HINT’, and ‘RWH_WRITE_LIFE_*’
constants, which allow to inform the kernel about the relative expected
lifetime of writes on a given inode or via a particular open file
description.  On Linux >= 5.1 and NetBSD, the ‘fcntl’ module exposes the
‘F_SEAL_FUTURE_WRITE’ constant for use with ‘F_ADD_SEALS’ and
‘F_GET_SEALS’ operations.  On FreeBSD, the ‘fcntl’ module exposes the
‘F_READAHEAD’, ‘F_ISUNIONSTACK’, and ‘F_KINFO’ constants.  On macOS and
FreeBSD, the ‘fcntl’ module exposes the ‘F_RDAHEAD’ constant.  On NetBSD
and AIX, the ‘fcntl’ module exposes the ‘F_CLOSEM’ constant.  On NetBSD,
the ‘fcntl’ module exposes the ‘F_MAXFD’ constant.  On macOS and NetBSD,
the ‘fcntl’ module exposes the ‘F_GETNOSIGPIPE’ and ‘F_SETNOSIGPIPE’
constant.

The module defines the following functions:

 -- Function: fcntl.fcntl (fd, cmd, arg=0, /)

     Perform the operation 'cmd' on file descriptor 'fd' (file objects
     providing a *note fileno(): 15f5. method are accepted as well).
     The values used for 'cmd' are operating system dependent, and are
     available as constants in the ‘fcntl’ module, using the same names
     as used in the relevant C header files.  The argument 'arg' can
     either be an integer value, a *note bytes: 1c2. object, or a
     string.  The type and size of 'arg' must match the type and size of
     the argument of the operation as specified in the relevant C
     documentation.

     When 'arg' is an integer, the function returns the integer return
     value of the C ‘fcntl()’ call.

     When the argument is bytes, it represents a binary structure, for
     example, created by *note struct.pack(): 12bd.  A string value is
     encoded to binary using the UTF-8 encoding.  The binary data is
     copied to a buffer whose address is passed to the C ‘fcntl()’ call.
     The return value after a successful call is the contents of the
     buffer, converted to a *note bytes: 1c2. object.  The length of the
     returned object will be the same as the length of the 'arg'
     argument.  This is limited to 1024 bytes.

     If the ‘fcntl()’ call fails, an *note OSError: 41a. is raised.

          Note: If the type or the size of 'arg' does not match the type
          or size of the argument of the operation (for example, if an
          integer is passed when a pointer is expected, or the
          information returned in the buffer by the operating system is
          larger than 1024 bytes), this is most likely to result in a
          segmentation violation or a more subtle data corruption.

     Raises an *note auditing event: 1a15. ‘fcntl.fcntl’ with arguments
     ‘fd’, ‘cmd’, ‘arg’.

 -- Function: fcntl.ioctl (fd, request, arg=0, mutate_flag=True, /)

     This function is identical to the *note fcntl(): 3670. function,
     except that the argument handling is even more complicated.

     The 'request' parameter is limited to values that can fit in
     32-bits or 64-bits, depending on the platform.  Additional
     constants of interest for use as the 'request' argument can be
     found in the *note termios: e1. module, under the same names as
     used in the relevant C header files.

     The parameter 'arg' can be an integer, a *note bytes-like object:
     d55, or a string.  The type and size of 'arg' must match the type
     and size of the argument of the operation as specified in the
     relevant C documentation.

     If 'arg' does not support the read-write buffer interface or the
     'mutate_flag' is false, behavior is as for the *note fcntl(): 3670.
     function.

     If 'arg' supports the read-write buffer interface (like *note
     bytearray: 2ea.) and 'mutate_flag' is true (the default), then the
     buffer is (in effect) passed to the underlying ‘ioctl()’ system
     call, the latter’s return code is passed back to the calling
     Python, and the buffer’s new contents reflect the action of the
     ‘ioctl()’.  This is a slight simplification, because if the
     supplied buffer is less than 1024 bytes long it is first copied
     into a static buffer 1024 bytes long which is then passed to
     ‘ioctl()’ and copied back into the supplied buffer.

     If the ‘ioctl()’ call fails, an *note OSError: 41a. exception is
     raised.

          Note: If the type or size of 'arg' does not match the type or
          size of the operation’s argument (for example, if an integer
          is passed when a pointer is expected, or the information
          returned in the buffer by the operating system is larger than
          1024 bytes, or the size of the mutable bytes-like object is
          too small), this is most likely to result in a segmentation
          violation or a more subtle data corruption.

     An example:

          >>> import array, fcntl, struct, termios, os
          >>> os.getpgrp()
          13341
          >>> struct.unpack('h', fcntl.ioctl(0, termios.TIOCGPGRP, "  "))[0]
          13341
          >>> buf = array.array('h', [0])
          >>> fcntl.ioctl(0, termios.TIOCGPGRP, buf, 1)
          0
          >>> buf
          array('h', [13341])

     Raises an *note auditing event: 1a15. ‘fcntl.ioctl’ with arguments
     ‘fd’, ‘request’, ‘arg’.

 -- Function: fcntl.flock (fd, operation, /)

     Perform the lock operation 'operation' on file descriptor 'fd'
     (file objects providing a *note fileno(): 15f5. method are accepted
     as well).  See the Unix manual ‘flock(2)(3)’ for details.  (On some
     systems, this function is emulated using ‘fcntl()’.)

     If the ‘flock()’ call fails, an *note OSError: 41a. exception is
     raised.

     Raises an *note auditing event: 1a15. ‘fcntl.flock’ with arguments
     ‘fd’, ‘operation’.

 -- Function: fcntl.lockf (fd, cmd, len=0, start=0, whence=0, /)

     This is essentially a wrapper around the *note fcntl(): 3670.
     locking calls.  'fd' is the file descriptor (file objects providing
     a *note fileno(): 15f5. method are accepted as well) of the file to
     lock or unlock, and 'cmd' is one of the following values:

      -- Data: fcntl.LOCK_UN

          Release an existing lock.

      -- Data: fcntl.LOCK_SH

          Acquire a shared lock.

      -- Data: fcntl.LOCK_EX

          Acquire an exclusive lock.

      -- Data: fcntl.LOCK_NB

          Bitwise OR with any of the other three ‘LOCK_*’ constants to
          make the request non-blocking.

     If ‘LOCK_NB’ is used and the lock cannot be acquired, an *note
     OSError: 41a. will be raised and the exception will have an 'errno'
     attribute set to *note EACCES: 2466. or *note EAGAIN: 2457.
     (depending on the operating system; for portability, check for both
     values).  On at least some systems, ‘LOCK_EX’ can only be used if
     the file descriptor refers to a file opened for writing.

     'len' is the number of bytes to lock, 'start' is the byte offset at
     which the lock starts, relative to 'whence', and 'whence' is as
     with *note io.IOBase.seek(): 12d3, specifically:

        * ‘0’ – relative to the start of the file (*note os.SEEK_SET:
          12d4.)

        * ‘1’ – relative to the current buffer position (*note
          os.SEEK_CUR: 12d5.)

        * ‘2’ – relative to the end of the file (*note os.SEEK_END:
          12d6.)

     The default for 'start' is 0, which means to start at the beginning
     of the file.  The default for 'len' is 0 which means to lock to the
     end of the file.  The default for 'whence' is also 0.

     Raises an *note auditing event: 1a15. ‘fcntl.lockf’ with arguments
     ‘fd’, ‘cmd’, ‘len’, ‘start’, ‘whence’.

Examples (all on a SVR4 compliant system):

     import struct, fcntl, os

     f = open(...)
     rv = fcntl.fcntl(f, fcntl.F_SETFL, os.O_NDELAY)

     lockdata = struct.pack('hhllhh', fcntl.F_WRLCK, 0, 0, 0, 0, 0)
     rv = fcntl.fcntl(f, fcntl.F_SETLKW, lockdata)

Note that in the first example the return value variable 'rv' will hold
an integer value; in the second example it will hold a *note bytes: 1c2.
object.  The structure lay-out for the 'lockdata' variable is system
dependent — therefore using the *note flock(): 4428. call may be better.

See also
........

Module *note os: a1.

     If the locking flags *note O_SHLOCK: 147d. and *note O_EXLOCK:
     147e. are present in the *note os: a1. module (on BSD only), the
     *note os.open(): dc0. function provides an alternative to the *note
     lockf(): 143a. and *note flock(): 4428. functions.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/fcntl(2)

   (2) https://manpages.debian.org/ioctl(2)

   (3) https://manpages.debian.org/flock(2)


File: python.info,  Node: resource — Resource usage information,  Next: syslog — Unix syslog library routines,  Prev: fcntl — The fcntl and ioctl system calls,  Up: Unix-specific services

5.34.9 ‘resource’ — Resource usage information
----------------------------------------------

__________________________________________________________________

This module provides basic mechanisms for measuring and controlling
system resources utilized by a program.

*note Availability: 1ef7.: Unix, not WASI.

Symbolic constants are used to specify particular system resources and
to request usage information about either the current process or its
children.

An *note OSError: 41a. is raised on syscall failure.

 -- Exception: resource.error

     A deprecated alias of *note OSError: 41a.

     Changed in version 3.3: Following PEP 3151(1), this class was made
     an alias of *note OSError: 41a.

* Menu:

* Resource Limits::
* Resource Usage::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3151/


File: python.info,  Node: Resource Limits,  Next: Resource Usage,  Up: resource — Resource usage information

5.34.9.1 Resource Limits
........................

Resources usage can be limited using the *note setrlimit(): 1625.
function described below.  Each resource is controlled by a pair of
limits: a soft limit and a hard limit.  The soft limit is the current
limit, and may be lowered or raised by a process over time.  The soft
limit can never exceed the hard limit.  The hard limit can be lowered to
any value greater than the soft limit, but not raised.  (Only processes
with the effective UID of the super-user can raise a hard limit.)

The specific resources that can be limited are system dependent.  They
are described in the ‘getrlimit(2)(1)’ man page.  The resources listed
below are supported when the underlying operating system supports them;
resources which cannot be checked or controlled by the operating system
are not defined in this module for those platforms.

 -- Data: resource.RLIM_INFINITY

     Constant used to represent the limit for an unlimited resource.

 -- Function: resource.getrlimit (resource)

     Returns a tuple ‘(soft, hard)’ with the current soft and hard
     limits of 'resource'.  Raises *note ValueError: 202. if an invalid
     resource is specified, or *note error: 4abb. if the underlying
     system call fails unexpectedly.

 -- Function: resource.setrlimit (resource, limits)

     Sets new limits of consumption of 'resource'.  The 'limits'
     argument must be a tuple ‘(soft, hard)’ of two integers describing
     the new limits.  A value of *note RLIM_INFINITY: 1624. can be used
     to request a limit that is unlimited.

     Raises *note ValueError: 202. if an invalid resource is specified,
     if the new soft limit exceeds the hard limit, or if a process tries
     to raise its hard limit.  Specifying a limit of *note
     RLIM_INFINITY: 1624. when the hard or system limit for that
     resource is not unlimited will result in a ‘ValueError’.  A process
     with the effective UID of super-user can request any valid limit
     value, including unlimited, but ‘ValueError’ will still be raised
     if the requested limit exceeds the system imposed limit.

     ‘setrlimit’ may also raise *note error: 4abb. if the underlying
     system call fails.

     VxWorks only supports setting *note RLIMIT_NOFILE: 4abd.

     Raises an *note auditing event: 1a15. ‘resource.setrlimit’ with
     arguments ‘resource’, ‘limits’.

 -- Function: resource.prlimit (pid, resource[, limits])

     Combines *note setrlimit(): 1625. and *note getrlimit(): 1623. in
     one function and supports to get and set the resources limits of an
     arbitrary process.  If 'pid' is 0, then the call applies to the
     current process.  'resource' and 'limits' have the same meaning as
     in ‘setrlimit()’, except that 'limits' is optional.

     When 'limits' is not given the function returns the 'resource'
     limit of the process 'pid'.  When 'limits' is given the 'resource'
     limit of the process is set and the former resource limit is
     returned.

     Raises *note ProcessLookupError: 1099. when 'pid' can’t be found
     and *note PermissionError: d6b. when the user doesn’t have
     ‘CAP_SYS_RESOURCE’ for the process.

     Raises an *note auditing event: 1a15. ‘resource.prlimit’ with
     arguments ‘pid’, ‘resource’, ‘limits’.

     *note Availability: 1ef7.: Linux >= 2.6.36 with glibc >= 2.13.

     Added in version 3.4.

These symbols define resources whose consumption can be controlled using
the *note setrlimit(): 1625. and *note getrlimit(): 1623. functions
described below.  The values of these symbols are exactly the constants
used by C programs.

The Unix man page for ‘getrlimit(2)(2)’ lists the available resources.
Note that not all systems use the same symbol or same value to denote
the same resource.  This module does not attempt to mask platform
differences — symbols not defined for a platform will not be available
from this module on that platform.

 -- Data: resource.RLIMIT_CORE

     The maximum size (in bytes) of a core file that the current process
     can create.  This may result in the creation of a partial core file
     if a larger core would be required to contain the entire process
     image.

 -- Data: resource.RLIMIT_CPU

     The maximum amount of processor time (in seconds) that a process
     can use.  If this limit is exceeded, a *note SIGXCPU: 3740. signal
     is sent to the process.  (See the *note signal: c6. module
     documentation for information about how to catch this signal and do
     something useful, e.g.  flush open files to disk.)

 -- Data: resource.RLIMIT_FSIZE

     The maximum size of a file which the process may create.

 -- Data: resource.RLIMIT_DATA

     The maximum size (in bytes) of the process’s heap.

 -- Data: resource.RLIMIT_STACK

     The maximum size (in bytes) of the call stack for the current
     process.  This only affects the stack of the main thread in a
     multi-threaded process.

 -- Data: resource.RLIMIT_RSS

     The maximum resident set size that should be made available to the
     process.

 -- Data: resource.RLIMIT_NPROC

     The maximum number of processes the current process may create.

 -- Data: resource.RLIMIT_NOFILE

     The maximum number of open file descriptors for the current
     process.

 -- Data: resource.RLIMIT_OFILE

     The BSD name for *note RLIMIT_NOFILE: 4abd.

 -- Data: resource.RLIMIT_MEMLOCK

     The maximum address space which may be locked in memory.

 -- Data: resource.RLIMIT_VMEM

     The largest area of mapped memory which the process may occupy.
     Usually an alias of *note RLIMIT_AS: 4ac7.

     *note Availability: 1ef7.: Solaris, FreeBSD, NetBSD.

 -- Data: resource.RLIMIT_AS

     The maximum area (in bytes) of address space which may be taken by
     the process.

 -- Data: resource.RLIMIT_MSGQUEUE

     The number of bytes that can be allocated for POSIX message queues.

     *note Availability: 1ef7.: Linux >= 2.6.8.

     Added in version 3.4.

 -- Data: resource.RLIMIT_NICE

     The ceiling for the process’s nice level (calculated as 20 -
     rlim_cur).

     *note Availability: 1ef7.: Linux >= 2.6.12.

     Added in version 3.4.

 -- Data: resource.RLIMIT_RTPRIO

     The ceiling of the real-time priority.

     *note Availability: 1ef7.: Linux >= 2.6.12.

     Added in version 3.4.

 -- Data: resource.RLIMIT_RTTIME

     The time limit (in microseconds) on CPU time that a process can
     spend under real-time scheduling without making a blocking syscall.

     *note Availability: 1ef7.: Linux >= 2.6.25.

     Added in version 3.4.

 -- Data: resource.RLIMIT_SIGPENDING

     The number of signals which the process may queue.

     *note Availability: 1ef7.: Linux >= 2.6.8.

     Added in version 3.4.

 -- Data: resource.RLIMIT_SBSIZE

     The maximum size (in bytes) of socket buffer usage for this user.
     This limits the amount of network memory, and hence the amount of
     mbufs, that this user may hold at any time.

     *note Availability: 1ef7.: FreeBSD, NetBSD.

     Added in version 3.4.

 -- Data: resource.RLIMIT_SWAP

     The maximum size (in bytes) of the swap space that may be reserved
     or used by all of this user id’s processes.  This limit is enforced
     only if bit 1 of the vm.overcommit sysctl is set.  Please see
     tuning(7)(3) for a complete description of this sysctl.

     *note Availability: 1ef7.: FreeBSD >= 8.

     Added in version 3.4.

 -- Data: resource.RLIMIT_NPTS

     The maximum number of pseudo-terminals created by this user id.

     *note Availability: 1ef7.: FreeBSD >= 8.

     Added in version 3.4.

 -- Data: resource.RLIMIT_KQUEUES

     The maximum number of kqueues this user id is allowed to create.

     *note Availability: 1ef7.: FreeBSD >= 11.

     Added in version 3.10.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/getrlimit(2)

   (2) https://manpages.debian.org/getrlimit(2)

   (3) https://man.freebsd.org/cgi/man.cgi?query=tuning&sektion=7


File: python.info,  Node: Resource Usage,  Prev: Resource Limits,  Up: resource — Resource usage information

5.34.9.2 Resource Usage
.......................

These functions are used to retrieve resource usage information:

 -- Function: resource.getrusage (who)

     This function returns an object that describes the resources
     consumed by either the current process or its children, as
     specified by the 'who' parameter.  The 'who' parameter should be
     specified using one of the ‘RUSAGE_*’ constants described below.

     A simple example:

          from resource import *
          import time

          # a non CPU-bound task
          time.sleep(3)
          print(getrusage(RUSAGE_SELF))

          # a CPU-bound task
          for i in range(10 ** 8):
             _ = 1 + 1
          print(getrusage(RUSAGE_SELF))

     The fields of the return value each describe how a particular
     system resource has been used, e.g.  amount of time spent running
     in user mode or number of times the process was swapped out of main
     memory.  Some values are dependent on the clock tick interval, e.g.
     the amount of memory the process is using.

     For backward compatibility, the return value is also accessible as
     a tuple of 16 elements.

     The fields ‘ru_utime’ and ‘ru_stime’ of the return value are
     floating-point values representing the amount of time spent
     executing in user mode and the amount of time spent executing in
     system mode, respectively.  The remaining values are integers.
     Consult the ‘getrusage(2)(1)’ man page for detailed information
     about these values.  A brief summary is presented here:

     Index        Field                      Resource
                                             
     ------------------------------------------------------------------------------------
                                             
     ‘0’          ‘ru_utime’                 time in user mode (float seconds)
                                             
                                             
     ‘1’          ‘ru_stime’                 time in system mode (float seconds)
                                             
                                             
     ‘2’          ‘ru_maxrss’                maximum resident set size
                                             
                                             
     ‘3’          ‘ru_ixrss’                 shared memory size
                                             
                                             
     ‘4’          ‘ru_idrss’                 unshared memory size
                                             
                                             
     ‘5’          ‘ru_isrss’                 unshared stack size
                                             
                                             
     ‘6’          ‘ru_minflt’                page faults not requiring I/O
                                             
                                             
     ‘7’          ‘ru_majflt’                page faults requiring I/O
                                             
                                             
     ‘8’          ‘ru_nswap’                 number of swap outs
                                             
                                             
     ‘9’          ‘ru_inblock’               block input operations
                                             
                                             
     ‘10’         ‘ru_oublock’               block output operations
                                             
                                             
     ‘11’         ‘ru_msgsnd’                messages sent
                                             
                                             
     ‘12’         ‘ru_msgrcv’                messages received
                                             
                                             
     ‘13’         ‘ru_nsignals’              signals received
                                             
                                             
     ‘14’         ‘ru_nvcsw’                 voluntary context switches
                                             
                                             
     ‘15’         ‘ru_nivcsw’                involuntary context switches
                                             

     This function will raise a *note ValueError: 202. if an invalid
     'who' parameter is specified.  It may also raise *note error: 4abb.
     exception in unusual circumstances.

 -- Function: resource.getpagesize ()

     Returns the number of bytes in a system page.  (This need not be
     the same as the hardware page size.)

The following ‘RUSAGE_*’ symbols are passed to the *note getrusage():
147f. function to specify which processes information should be provided
for.

 -- Data: resource.RUSAGE_SELF

     Pass to *note getrusage(): 147f. to request resources consumed by
     the calling process, which is the sum of resources used by all
     threads in the process.

 -- Data: resource.RUSAGE_CHILDREN

     Pass to *note getrusage(): 147f. to request resources consumed by
     child processes of the calling process which have been terminated
     and waited for.

 -- Data: resource.RUSAGE_BOTH

     Pass to *note getrusage(): 147f. to request resources consumed by
     both the current process and child processes.  May not be available
     on all systems.

 -- Data: resource.RUSAGE_THREAD

     Pass to *note getrusage(): 147f. to request resources consumed by
     the current thread.  May not be available on all systems.

     Added in version 3.2.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/getrusage(2)


File: python.info,  Node: syslog — Unix syslog library routines,  Prev: resource — Resource usage information,  Up: Unix-specific services

5.34.10 ‘syslog’ — Unix syslog library routines
-----------------------------------------------

__________________________________________________________________

This module provides an interface to the Unix ‘syslog’ library routines.
Refer to the Unix manual pages for a detailed description of the
‘syslog’ facility.

*note Availability: 1ef7.: Unix, not WASI, not iOS.

This module wraps the system ‘syslog’ family of routines.  A pure Python
library that can speak to a syslog server is available in the *note
logging.handlers: 89. module as *note SysLogHandler: 65f.

The module defines the following functions:

 -- Function: syslog.syslog (message)

 -- Function: syslog.syslog (priority, message)

     Send the string 'message' to the system logger.  A trailing newline
     is added if necessary.  Each message is tagged with a priority
     composed of a 'facility' and a 'level'.  The optional 'priority'
     argument, which defaults to *note LOG_INFO: 4ad1, determines the
     message priority.  If the facility is not encoded in 'priority'
     using logical-or (‘LOG_INFO | LOG_USER’), the value given in the
     *note openlog(): 541. call is used.

     If *note openlog(): 541. has not been called prior to the call to
     ‘syslog()’, ‘openlog()’ will be called with no arguments.

     Raises an *note auditing event: 1a15. ‘syslog.syslog’ with
     arguments ‘priority’, ‘message’.

     Changed in version 3.2: In previous versions, *note openlog(): 541.
     would not be called automatically if it wasn’t called prior to the
     call to ‘syslog()’, deferring to the syslog implementation to call
     ‘openlog()’.

     Changed in version 3.12: This function is restricted in
     subinterpreters.  (Only code that runs in multiple interpreters is
     affected and the restriction is not relevant for most users.)
     *note openlog(): 541. must be called in the main interpreter before
     ‘syslog()’ may be used in a subinterpreter.  Otherwise it will
     raise *note RuntimeError: 195.

 -- Function: syslog.openlog ([ident[, logoption[, facility]]])

     Logging options of subsequent *note syslog(): dc. calls can be set
     by calling ‘openlog()’.  ‘syslog()’ will call ‘openlog()’ with no
     arguments if the log is not currently open.

     The optional 'ident' keyword argument is a string which is
     prepended to every message, and defaults to ‘sys.argv[0]’ with
     leading path components stripped.  The optional 'logoption' keyword
     argument (default is 0) is a bit field – see below for possible
     values to combine.  The optional 'facility' keyword argument
     (default is *note LOG_USER: 4ad2.) sets the default facility for
     messages which do not have a facility explicitly encoded.

     Raises an *note auditing event: 1a15. ‘syslog.openlog’ with
     arguments ‘ident’, ‘logoption’, ‘facility’.

     Changed in version 3.2: In previous versions, keyword arguments
     were not allowed, and 'ident' was required.

     Changed in version 3.12: This function is restricted in
     subinterpreters.  (Only code that runs in multiple interpreters is
     affected and the restriction is not relevant for most users.)  This
     may only be called in the main interpreter.  It will raise *note
     RuntimeError: 195. if called in a subinterpreter.

 -- Function: syslog.closelog ()

     Reset the syslog module values and call the system library
     ‘closelog()’.

     This causes the module to behave as it does when initially
     imported.  For example, *note openlog(): 541. will be called on the
     first *note syslog(): dc. call (if ‘openlog()’ hasn’t already been
     called), and 'ident' and other ‘openlog()’ parameters are reset to
     defaults.

     Raises an *note auditing event: 1a15. ‘syslog.closelog’ with no
     arguments.

     Changed in version 3.12: This function is restricted in
     subinterpreters.  (Only code that runs in multiple interpreters is
     affected and the restriction is not relevant for most users.)  This
     may only be called in the main interpreter.  It will raise *note
     RuntimeError: 195. if called in a subinterpreter.

 -- Function: syslog.setlogmask (maskpri)

     Set the priority mask to 'maskpri' and return the previous mask
     value.  Calls to *note syslog(): dc. with a priority level not set
     in 'maskpri' are ignored.  The default is to log all priorities.
     The function ‘LOG_MASK(pri)’ calculates the mask for the individual
     priority 'pri'.  The function ‘LOG_UPTO(pri)’ calculates the mask
     for all priorities up to and including 'pri'.

     Raises an *note auditing event: 1a15. ‘syslog.setlogmask’ with
     argument ‘maskpri’.

The module defines the following constants:

 -- Data: syslog.LOG_EMERG
 -- Data: syslog.LOG_ALERT
 -- Data: syslog.LOG_CRIT
 -- Data: syslog.LOG_ERR
 -- Data: syslog.LOG_WARNING
 -- Data: syslog.LOG_NOTICE
 -- Data: syslog.LOG_INFO
 -- Data: syslog.LOG_DEBUG

     Priority levels (high to low).

 -- Data: syslog.LOG_AUTH
 -- Data: syslog.LOG_AUTHPRIV
 -- Data: syslog.LOG_CRON
 -- Data: syslog.LOG_DAEMON
 -- Data: syslog.LOG_FTP
 -- Data: syslog.LOG_INSTALL
 -- Data: syslog.LOG_KERN
 -- Data: syslog.LOG_LAUNCHD
 -- Data: syslog.LOG_LPR
 -- Data: syslog.LOG_MAIL
 -- Data: syslog.LOG_NETINFO
 -- Data: syslog.LOG_NEWS
 -- Data: syslog.LOG_RAS
 -- Data: syslog.LOG_REMOTEAUTH
 -- Data: syslog.LOG_SYSLOG
 -- Data: syslog.LOG_USER
 -- Data: syslog.LOG_UUCP
 -- Data: syslog.LOG_LOCAL0
 -- Data: syslog.LOG_LOCAL1
 -- Data: syslog.LOG_LOCAL2
 -- Data: syslog.LOG_LOCAL3
 -- Data: syslog.LOG_LOCAL4
 -- Data: syslog.LOG_LOCAL5
 -- Data: syslog.LOG_LOCAL6
 -- Data: syslog.LOG_LOCAL7

     Facilities, depending on availability in ‘<syslog.h>’ for *note
     LOG_AUTHPRIV: 4adb, *note LOG_FTP: 4ade, *note LOG_NETINFO: 4ae4,
     *note LOG_REMOTEAUTH: 4ae7, *note LOG_INSTALL: 4adf. and *note
     LOG_RAS: 4ae6.

     Changed in version 3.13: Added *note LOG_FTP: 4ade, *note
     LOG_NETINFO: 4ae4, *note LOG_REMOTEAUTH: 4ae7, *note LOG_INSTALL:
     4adf, *note LOG_RAS: 4ae6, and *note LOG_LAUNCHD: 4ae1.

 -- Data: syslog.LOG_PID
 -- Data: syslog.LOG_CONS
 -- Data: syslog.LOG_NDELAY
 -- Data: syslog.LOG_ODELAY
 -- Data: syslog.LOG_NOWAIT
 -- Data: syslog.LOG_PERROR

     Log options, depending on availability in ‘<syslog.h>’ for *note
     LOG_ODELAY: 4af5, *note LOG_NOWAIT: 4af6. and *note LOG_PERROR:
     4af7.

* Menu:

* Examples: Examples<36>.


File: python.info,  Node: Examples<36>,  Up: syslog — Unix syslog library routines

5.34.10.1 Examples
..................

* Menu:

* Simple example::


File: python.info,  Node: Simple example,  Up: Examples<36>

5.34.10.2 Simple example
........................

A simple set of examples:

     import syslog

     syslog.syslog('Processing started')
     if error:
         syslog.syslog(syslog.LOG_ERR, 'Processing started')

An example of setting some log options, these would include the process
ID in logged messages, and write the messages to the destination
facility used for mail logging:

     syslog.openlog(logoption=syslog.LOG_PID, facility=syslog.LOG_MAIL)
     syslog.syslog('E-mail processing initiated...')


File: python.info,  Node: Modules command-line interface CLI,  Next: Superseded Modules,  Prev: Unix-specific services,  Up: The Python Standard Library

5.35 Modules command-line interface (CLI)
=========================================

The following modules have a command-line interface.

   * *note ast: 48a5.

   * *note asyncio: 3498.

   * *note base64: e.

   * *note calendar: 26a7.

   * *note code: 1a.

   * *note compileall: 4969.

   * *note cProfile: 27.: see *note profile: 44c5.

   * *note difflib: 24e8.

   * *note dis: 4980.

   * *note doctest: 4229.

   * ‘encodings.rot_13’

   * *note ensurepip: 456f.

   * *note filecmp: 5a.

   * *note fileinput: 5b.

   * *note ftplib: 5e.

   * *note gzip: 2b58.

   * *note http.server: f8a.

   * *note idlelib: 40e2.

   * *note inspect: f94.

   * *note json.tool: 38aa.

   * *note mimetypes: 8f.

   * *note pdb: 448d.

   * *note pickle: a6.

   * *note pickletools: 49f0.

   * *note platform: 2f42.

   * *note poplib: ac.

   * *note profile: 44c5.

   * *note pstats: b0.

   * *note py_compile: 4960.

   * *note pyclbr: b4.

   * *note pydoc: b5.

   * *note quopri: b7.

   * *note random: 154.

   * *note runpy: be.

   * *note site: 4744.

   * *note sqlite3: 444.

   * *note symtable: 48db.

   * *note sysconfig: 4639.

   * *note tabnanny: dd.

   * *note tarfile: 1006.

   * ‘this’

   * *note timeit: 44e9.

   * *note tokenize: 4931.

   * *note trace: 4506.

   * *note turtledemo: 102.

   * *note unittest: 42a2.

   * *note uuid: 447.

   * *note venv: 457c.

   * *note webbrowser: 3b91.

   * *note zipapp: 4596.

   * *note zipfile: 2bc8.

See also the *note Python command-line interface: 1b4f.


File: python.info,  Node: Superseded Modules,  Next: Removed Modules,  Prev: Modules command-line interface CLI,  Up: The Python Standard Library

5.36 Superseded Modules
=======================

The modules described in this chapter have been superseded by other
modules for most use cases, and are retained primarily to preserve
backwards compatibility.

Modules may appear in this chapter because they only cover a limited
subset of a problem space, and a more generally applicable solution is
available elsewhere in the standard library (for example, *note getopt:
61. covers the very specific task of “mimic the C ‘getopt()’ API in
Python”, rather than the broader command line option parsing and
argument parsing capabilities offered by *note optparse: a0. and *note
argparse: 6.).

Alternatively, modules may appear in this chapter because they are
deprecated outright, and awaiting removal in a future release, or they
are *note soft deprecated: 209. and their use is actively discouraged in
new projects.  With the removal of various obsolete modules through PEP
594(1), there are currently no modules in this latter category.

* Menu:

* getopt — C-style parser for command line options::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/


File: python.info,  Node: getopt — C-style parser for command line options,  Up: Superseded Modules

5.36.1 ‘getopt’ — C-style parser for command line options
---------------------------------------------------------

'Source code:' Lib/getopt.py(1)

     Note: This module is considered feature complete.  A more
     declarative and extensible alternative to this API is provided in
     the *note optparse: a0. module.  Further functional enhancements
     for command line parameter processing are provided either as third
     party modules on PyPI, or else as features in the *note argparse:
     6. module.

__________________________________________________________________

This module helps scripts to parse the command line arguments in
‘sys.argv’.  It supports the same conventions as the Unix ‘getopt()’
function (including the special meanings of arguments of the form ‘‘-’’
and ‘‘--’‘).  Long options similar to those supported by GNU software
may be used as well via an optional third argument.

Users who are unfamiliar with the Unix ‘getopt()’ function should
consider using the *note argparse: 6. module instead.  Users who are
familiar with the Unix ‘getopt()’ function, but would like to get
equivalent behavior while writing less code and getting better help and
error messages should consider using the *note optparse: a0. module.
See *note Choosing an argument parsing library: 305c. for additional
details.

This module provides two functions and an exception:

 -- Function: getopt.getopt (args, shortopts, longopts=[])

     Parses command line options and parameter list.  'args' is the
     argument list to be parsed, without the leading reference to the
     running program.  Typically, this means ‘sys.argv[1:]’.
     'shortopts' is the string of option letters that the script wants
     to recognize, with options that require an argument followed by a
     colon (‘':'’; i.e., the same format that Unix ‘getopt()’ uses).

          Note: Unlike GNU ‘getopt()’, after a non-option argument, all
          further arguments are considered also non-options.  This is
          similar to the way non-GNU Unix systems work.

     'longopts', if specified, must be a list of strings with the names
     of the long options which should be supported.  The leading ‘'--'’
     characters should not be included in the option name.  Long options
     which require an argument should be followed by an equal sign
     (‘'='’).  Optional arguments are not supported.  To accept only
     long options, 'shortopts' should be an empty string.  Long options
     on the command line can be recognized so long as they provide a
     prefix of the option name that matches exactly one of the accepted
     options.  For example, if 'longopts' is ‘['foo', 'frob']’, the
     option ‘--fo’ will match as ‘--foo’, but ‘--f’ will not match
     uniquely, so *note GetoptError: 4b03. will be raised.

     The return value consists of two elements: the first is a list of
     ‘(option, value)’ pairs; the second is the list of program
     arguments left after the option list was stripped (this is a
     trailing slice of 'args').  Each option-and-value pair returned has
     the option as its first element, prefixed with a hyphen for short
     options (e.g., ‘'-x'’) or two hyphens for long options (e.g.,
     ‘'--long-option'’), and the option argument as its second element,
     or an empty string if the option has no argument.  The options
     occur in the list in the same order in which they were found, thus
     allowing multiple occurrences.  Long and short options may be
     mixed.

 -- Function: getopt.gnu_getopt (args, shortopts, longopts=[])

     This function works like *note getopt(): 61, except that GNU style
     scanning mode is used by default.  This means that option and
     non-option arguments may be intermixed.  The ‘getopt()’ function
     stops processing options as soon as a non-option argument is
     encountered.

     If the first character of the option string is ‘'+'’, or if the
     environment variable ‘POSIXLY_CORRECT’ is set, then option
     processing stops as soon as a non-option argument is encountered.

 -- Exception: getopt.GetoptError

     This is raised when an unrecognized option is found in the argument
     list or when an option requiring an argument is given none.  The
     argument to the exception is a string indicating the cause of the
     error.  For long options, an argument given to an option which does
     not require one will also cause this exception to be raised.  The
     attributes ‘msg’ and ‘opt’ give the error message and related
     option; if there is no specific option to which the exception
     relates, ‘opt’ is an empty string.

 -- Exception: getopt.error

     Alias for *note GetoptError: 4b03.; for backward compatibility.

An example using only Unix style options:

     >>> import getopt
     >>> args = '-a -b -cfoo -d bar a1 a2'.split()
     >>> args
     ['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2']
     >>> optlist, args = getopt.getopt(args, 'abc:d:')
     >>> optlist
     [('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')]
     >>> args
     ['a1', 'a2']

Using long option names is equally easy:

     >>> s = '--condition=foo --testing --output-file abc.def -x a1 a2'
     >>> args = s.split()
     >>> args
     ['--condition=foo', '--testing', '--output-file', 'abc.def', '-x', 'a1', 'a2']
     >>> optlist, args = getopt.getopt(args, 'x', [
     ...     'condition=', 'output-file=', 'testing'])
     >>> optlist
     [('--condition', 'foo'), ('--testing', ''), ('--output-file', 'abc.def'), ('-x', '')]
     >>> args
     ['a1', 'a2']

In a script, typical usage is something like this:

     import getopt, sys

     def main():
         try:
             opts, args = getopt.getopt(sys.argv[1:], "ho:v", ["help", "output="])
         except getopt.GetoptError as err:
             # print help information and exit:
             print(err)  # will print something like "option -a not recognized"
             usage()
             sys.exit(2)
         output = None
         verbose = False
         for o, a in opts:
             if o == "-v":
                 verbose = True
             elif o in ("-h", "--help"):
                 usage()
                 sys.exit()
             elif o in ("-o", "--output"):
                 output = a
             else:
                 assert False, "unhandled option"
         process(args, output=output, verbose=verbose)

     if __name__ == "__main__":
         main()

Note that an equivalent command line interface could be produced with
less code and more informative help and error messages by using the
*note optparse: a0. module:

     import optparse

     if __name__ == '__main__':
         parser = optparse.OptionParser()
         parser.add_option('-o', '--output')
         parser.add_option('-v', dest='verbose', action='store_true')
         opts, args = parser.parse_args()
         process(args, output=opts.output, verbose=opts.verbose)

A roughly equivalent command line interface for this case can also be
produced by using the *note argparse: 6. module:

     import argparse

     if __name__ == '__main__':
         parser = argparse.ArgumentParser()
         parser.add_argument('-o', '--output')
         parser.add_argument('-v', dest='verbose', action='store_true')
         parser.add_argument('rest', nargs='*')
         args = parser.parse_args()
         process(args.rest, output=args.output, verbose=args.verbose)

See *note Choosing an argument parsing library: 305c. for details on how
the ‘argparse’ version of this code differs in behaviour from the
‘optparse’ (and ‘getopt’) version.

See also
........

Module *note optparse: a0.

     Declarative command line option parsing.

Module *note argparse: 6.

     More opinionated command line option and argument parsing library.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Lib/getopt.py


File: python.info,  Node: Removed Modules,  Next: Security Considerations<3>,  Prev: Superseded Modules,  Up: The Python Standard Library

5.37 Removed Modules
====================

The modules described in this chapter have been removed from the Python
standard library.  They are documented here to help people find
replacements.

* Menu:

* aifc — Read and write AIFF and AIFC files::
* asynchat — Asynchronous socket command/response handler::
* asyncore — Asynchronous socket handler::
* audioop — Manipulate raw audio data::
* cgi — Common Gateway Interface support::
* cgitb — Traceback manager for CGI scripts::
* chunk — Read IFF chunked data::
* crypt — Function to check Unix passwords::
* distutils — Building and installing Python modules::
* imghdr — Determine the type of an image::
* imp — Access the import internals::
* mailcap — Mailcap file handling::
* msilib — Read and write Microsoft Installer files::
* nis — Interface to Sun’s NIS (Yellow Pages): nis — Interface to Sun’s NIS Yellow Pages.
* nntplib — NNTP protocol client::
* ossaudiodev — Access to OSS-compatible audio devices::
* pipes — Interface to shell pipelines::
* smtpd — SMTP Server::
* sndhdr — Determine type of sound file::
* spwd — The shadow password database::
* sunau — Read and write Sun AU files::
* telnetlib — Telnet client::
* uu — Encode and decode uuencode files::
* xdrlib — Encode and decode XDR data::


File: python.info,  Node: aifc — Read and write AIFF and AIFC files,  Next: asynchat — Asynchronous socket command/response handler,  Up: Removed Modules

5.37.1 ‘aifc’ — Read and write AIFF and AIFC files
--------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘aifc’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/aifc.html


File: python.info,  Node: asynchat — Asynchronous socket command/response handler,  Next: asyncore — Asynchronous socket handler,  Prev: aifc — Read and write AIFF and AIFC files,  Up: Removed Modules

5.37.2 ‘asynchat’ — Asynchronous socket command/response handler
----------------------------------------------------------------

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.12: 505. after being deprecated in Python 3.6.
The removal was decided in PEP 594(1).

Applications should use the *note asyncio: a. module instead.

The last version of Python that provided the ‘asynchat’ module was
Python 3.11(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.11/library/asynchat.html


File: python.info,  Node: asyncore — Asynchronous socket handler,  Next: audioop — Manipulate raw audio data,  Prev: asynchat — Asynchronous socket command/response handler,  Up: Removed Modules

5.37.3 ‘asyncore’ — Asynchronous socket handler
-----------------------------------------------

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.12: 505. after being deprecated in Python 3.6.
The removal was decided in PEP 594(1).

Applications should use the *note asyncio: a. module instead.

The last version of Python that provided the ‘asyncore’ module was
Python 3.11(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.11/library/asyncore.html


File: python.info,  Node: audioop — Manipulate raw audio data,  Next: cgi — Common Gateway Interface support,  Prev: asyncore — Asynchronous socket handler,  Up: Removed Modules

5.37.4 ‘audioop’ — Manipulate raw audio data
--------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘audioop’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/audioop.html


File: python.info,  Node: cgi — Common Gateway Interface support,  Next: cgitb — Traceback manager for CGI scripts,  Prev: audioop — Manipulate raw audio data,  Up: Removed Modules

5.37.5 ‘cgi’ — Common Gateway Interface support
-----------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

A fork of the module on PyPI can be used instead: legacy-cgi(2).  This
is a copy of the cgi module, no longer maintained or supported by the
core Python team.

The last version of Python that provided the ‘cgi’ module was Python
3.12(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/legacy-cgi/

   (3) https://docs.python.org/3.12/library/cgi.html


File: python.info,  Node: cgitb — Traceback manager for CGI scripts,  Next: chunk — Read IFF chunked data,  Prev: cgi — Common Gateway Interface support,  Up: Removed Modules

5.37.6 ‘cgitb’ — Traceback manager for CGI scripts
--------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

A fork of the module on PyPI can now be used instead: legacy-cgi(2).
This is a copy of the cgi module, no longer maintained or supported by
the core Python team.

The last version of Python that provided the ‘cgitb’ module was Python
3.12(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/legacy-cgi/

   (3) https://docs.python.org/3.12/library/cgitb.html


File: python.info,  Node: chunk — Read IFF chunked data,  Next: crypt — Function to check Unix passwords,  Prev: cgitb — Traceback manager for CGI scripts,  Up: Removed Modules

5.37.7 ‘chunk’ — Read IFF chunked data
--------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘chunk’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/chunk.html


File: python.info,  Node: crypt — Function to check Unix passwords,  Next: distutils — Building and installing Python modules,  Prev: chunk — Read IFF chunked data,  Up: Removed Modules

5.37.8 ‘crypt’ — Function to check Unix passwords
-------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

Applications can use the *note hashlib: 68. module from the standard
library.  Other possible replacements are third-party libraries from
PyPI: legacycrypt(2), bcrypt(3), or argon2-cffi(4).  These are not
supported or maintained by the Python core team.

The last version of Python that provided the ‘crypt’ module was Python
3.12(5).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/legacycrypt/

   (3) https://pypi.org/project/bcrypt/

   (4) https://pypi.org/project/argon2-cffi/

   (5) https://docs.python.org/3.12/library/crypt.html


File: python.info,  Node: distutils — Building and installing Python modules,  Next: imghdr — Determine the type of an image,  Prev: crypt — Function to check Unix passwords,  Up: Removed Modules

5.37.9 ‘distutils’ — Building and installing Python modules
-----------------------------------------------------------

Deprecated since version 3.10, removed in version 3.12.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.12: 50b. after being deprecated in Python
3.10.  The removal was decided in PEP 632(1), which has migration
advice(2).

The last version of Python that provided the ‘distutils’ module was
Python 3.11(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0632/

   (2) https://peps.python.org/pep-0632/#migration-advice

   (3) https://docs.python.org/3.11/library/distutils.html


File: python.info,  Node: imghdr — Determine the type of an image,  Next: imp — Access the import internals,  Prev: distutils — Building and installing Python modules,  Up: Removed Modules

5.37.10 ‘imghdr’ — Determine the type of an image
-------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

Possible replacements are third-party libraries from PyPI: filetype(2),
puremagic(3), or python-magic(4).  These are not supported or maintained
by the Python core team.

The last version of Python that provided the ‘imghdr’ module was Python
3.12(5).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/filetype/

   (3) https://pypi.org/project/puremagic/

   (4) https://pypi.org/project/python-magic/

   (5) https://docs.python.org/3.12/library/imghdr.html


File: python.info,  Node: imp — Access the import internals,  Next: mailcap — Mailcap file handling,  Prev: imghdr — Determine the type of an image,  Up: Removed Modules

5.37.11 ‘imp’ — Access the import internals
-------------------------------------------

Deprecated since version 3.4, removed in version 3.12.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.12: 515. after being deprecated in Python 3.4.

The *note removal notice: 515. includes guidance for migrating code from
‘imp’ to *note importlib: 77.

The last version of Python that provided the ‘imp’ module was Python
3.11(1).

   ---------- Footnotes ----------

   (1) https://docs.python.org/3.11/library/imp.html


File: python.info,  Node: mailcap — Mailcap file handling,  Next: msilib — Read and write Microsoft Installer files,  Prev: imp — Access the import internals,  Up: Removed Modules

5.37.12 ‘mailcap’ — Mailcap file handling
-----------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘mailcap’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/mailcap.html


File: python.info,  Node: msilib — Read and write Microsoft Installer files,  Next: nis — Interface to Sun’s NIS Yellow Pages,  Prev: mailcap — Mailcap file handling,  Up: Removed Modules

5.37.13 ‘msilib’ — Read and write Microsoft Installer files
-----------------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘msilib’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/msilib.html


File: python.info,  Node: nis — Interface to Sun’s NIS Yellow Pages,  Next: nntplib — NNTP protocol client,  Prev: msilib — Read and write Microsoft Installer files,  Up: Removed Modules

5.37.14 ‘nis’ — Interface to Sun’s NIS (Yellow Pages)
-----------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘nis’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/nis.html


File: python.info,  Node: nntplib — NNTP protocol client,  Next: ossaudiodev — Access to OSS-compatible audio devices,  Prev: nis — Interface to Sun’s NIS Yellow Pages,  Up: Removed Modules

5.37.15 ‘nntplib’ — NNTP protocol client
----------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘nntplib’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/nntplib.html


File: python.info,  Node: ossaudiodev — Access to OSS-compatible audio devices,  Next: pipes — Interface to shell pipelines,  Prev: nntplib — NNTP protocol client,  Up: Removed Modules

5.37.16 ‘ossaudiodev’ — Access to OSS-compatible audio devices
--------------------------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘ossaudiodev’ module was
Python 3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/ossaudiodev.html


File: python.info,  Node: pipes — Interface to shell pipelines,  Next: smtpd — SMTP Server,  Prev: ossaudiodev — Access to OSS-compatible audio devices,  Up: Removed Modules

5.37.17 ‘pipes’ — Interface to shell pipelines
----------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

Applications should use the *note subprocess: d6. module instead.

The last version of Python that provided the ‘pipes’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/pipes.html


File: python.info,  Node: smtpd — SMTP Server,  Next: sndhdr — Determine type of sound file,  Prev: pipes — Interface to shell pipelines,  Up: Removed Modules

5.37.18 ‘smtpd’ — SMTP Server
-----------------------------

Deprecated since version 3.6, removed in version 3.12.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.12: 505. after being deprecated in Python 3.6.
The removal was decided in PEP 594(1).

A possible replacement is the third-party aiosmtpd(2) library.  This
library is not maintained or supported by the Python core team.

The last version of Python that provided the ‘smtpd’ module was Python
3.11(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/aiosmtpd/

   (3) https://docs.python.org/3.11/library/smtpd.html


File: python.info,  Node: sndhdr — Determine type of sound file,  Next: spwd — The shadow password database,  Prev: smtpd — SMTP Server,  Up: Removed Modules

5.37.19 ‘sndhdr’ — Determine type of sound file
-----------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

Possible replacements are third-party modules from PyPI: filetype(2),
puremagic(3), or python-magic(4).  These are not supported or maintained
by the Python core team.

The last version of Python that provided the ‘sndhdr’ module was Python
3.12(5).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/filetype/

   (3) https://pypi.org/project/puremagic/

   (4) https://pypi.org/project/python-magic/

   (5) https://docs.python.org/3.12/library/sndhdr.html


File: python.info,  Node: spwd — The shadow password database,  Next: sunau — Read and write Sun AU files,  Prev: sndhdr — Determine type of sound file,  Up: Removed Modules

5.37.20 ‘spwd’ — The shadow password database
---------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

A possible replacement is the third-party library python-pam(2).  This
library is not supported or maintained by the Python core team.

The last version of Python that provided the ‘spwd’ module was Python
3.12(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/python-pam/

   (3) https://docs.python.org/3.12/library/spwd.html


File: python.info,  Node: sunau — Read and write Sun AU files,  Next: telnetlib — Telnet client,  Prev: spwd — The shadow password database,  Up: Removed Modules

5.37.21 ‘sunau’ — Read and write Sun AU files
---------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘sunau’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/sunau.html


File: python.info,  Node: telnetlib — Telnet client,  Next: uu — Encode and decode uuencode files,  Prev: sunau — Read and write Sun AU files,  Up: Removed Modules

5.37.22 ‘telnetlib’ — Telnet client
-----------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

Possible replacements are third-party libraries from PyPI: telnetlib3(2)
or Exscript(3).  These are not supported or maintained by the Python
core team.

The last version of Python that provided the ‘telnetlib’ module was
Python 3.12(4).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://pypi.org/project/telnetlib3/

   (3) https://pypi.org/project/Exscript/

   (4) https://docs.python.org/3.12/library/telnetlib.html


File: python.info,  Node: uu — Encode and decode uuencode files,  Next: xdrlib — Encode and decode XDR data,  Prev: telnetlib — Telnet client,  Up: Removed Modules

5.37.23 ‘uu’ — Encode and decode uuencode files
-----------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘uu’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/uu.html


File: python.info,  Node: xdrlib — Encode and decode XDR data,  Prev: uu — Encode and decode uuencode files,  Up: Removed Modules

5.37.24 ‘xdrlib’ — Encode and decode XDR data
---------------------------------------------

Deprecated since version 3.11, removed in version 3.13.

This module is no longer part of the Python standard library.  It was
*note removed in Python 3.13: 143. after being deprecated in Python
3.11.  The removal was decided in PEP 594(1).

The last version of Python that provided the ‘xdrlib’ module was Python
3.12(2).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0594/

   (2) https://docs.python.org/3.12/library/xdrlib.html


File: python.info,  Node: Security Considerations<3>,  Prev: Removed Modules,  Up: The Python Standard Library

5.38 Security Considerations
============================

The following modules have specific security considerations:

   * *note base64: e.: *note base64 security considerations: 3983. in
     RFC 4648(1)

   * *note hashlib: 68.: *note all constructors take a “usedforsecurity”
     keyword-only argument disabling known insecure and blocked
     algorithms: 2cc6.

   * *note http.server: 72. is not suitable for production use, only
     implementing basic security checks.  See the *note security
     considerations: 3dbc.

   * *note logging: 87.: *note Logging configuration uses eval(): 2eaa.

   * *note multiprocessing: 94.: *note Connection.recv() uses pickle:
     3382.

   * *note pickle: a6.: *note Restricting globals in pickle: 2a6e.

   * *note random: b8. shouldn’t be used for security purposes, use
     *note secrets: c0. instead

   * *note shelve: c3.: *note shelve is based on pickle and thus
     unsuitable for dealing with untrusted sources: 2a8c.

   * *note ssl: d0.: *note SSL/TLS security considerations: 3564.

   * *note subprocess: d6.: *note Subprocess security considerations:
     3426.

   * *note tempfile: e0.: *note mktemp is deprecated due to
     vulnerability to race conditions: 2a29.

   * *note xml: 120.: *note XML security: 39b7.

   * *note zipfile: 131.: *note maliciously prepared .zip files can
     cause disk volume exhaustion: 2bd7.

The *note -I: 968. command line option can be used to run Python in
isolated mode.  When it cannot be used, the *note -P: 5a7. option or the
*note PYTHONSAFEPATH: 5a8. environment variable can be used to not
prepend a potentially unsafe path to *note sys.path: 3b7. such as the
current directory, the script’s directory or an empty string.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc4648.html


File: python.info,  Node: Extending and Embedding the Python Interpreter,  Next: Python/C API Reference Manual,  Prev: The Python Standard Library,  Up: Top

6 Extending and Embedding the Python Interpreter
************************************************

This document describes how to write modules in C or C++ to extend the
Python interpreter with new modules.  Those modules can not only define
new functions but also new object types and their methods.  The document
also describes how to embed the Python interpreter in another
application, for use as an extension language.  Finally, it shows how to
compile and link extension modules so that they can be loaded
dynamically (at run time) into the interpreter, if the underlying
operating system supports this feature.

This document assumes basic knowledge about Python.  For an informal
introduction to the language, see *note The Python Tutorial: 1d6d.
*note The Python Language Reference: 145. gives a more formal definition
of the language.  *note The Python Standard Library: 144. documents the
existing object types, functions and modules (both built-in and written
in Python) that give the language its wide application range.

For a detailed description of the whole Python/C API, see the separate
*note Python/C API Reference Manual: 1d6f.

* Menu:

* Recommended third party tools::
* Creating extensions without third party tools::
* Embedding the CPython runtime in a larger application::


File: python.info,  Node: Recommended third party tools,  Next: Creating extensions without third party tools,  Up: Extending and Embedding the Python Interpreter

6.1 Recommended third party tools
=================================

This guide only covers the basic tools for creating extensions provided
as part of this version of CPython.  Some *note third party tools: 4b58.
offer both simpler and more sophisticated approaches to creating C and
C++ extensions for Python.


File: python.info,  Node: Creating extensions without third party tools,  Next: Embedding the CPython runtime in a larger application,  Prev: Recommended third party tools,  Up: Extending and Embedding the Python Interpreter

6.2 Creating extensions without third party tools
=================================================

This section of the guide covers creating C and C++ extensions without
assistance from third party tools.  It is intended primarily for
creators of those tools, rather than being a recommended way to create
your own C extensions.

See also
........

PEP 489(1) – Multi-phase extension module initialization

* Menu:

* Extending Python with C or C++::
* Defining Extension Types; Tutorial: Defining Extension Types Tutorial.
* Defining Extension Types; Assorted Topics: Defining Extension Types Assorted Topics.
* Building C and C++ Extensions::
* Building C and C++ Extensions on Windows::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0489/


File: python.info,  Node: Extending Python with C or C++,  Next: Defining Extension Types Tutorial,  Up: Creating extensions without third party tools

6.2.1 Extending Python with C or C++
------------------------------------

It is quite easy to add new built-in modules to Python, if you know how
to program in C. Such 'extension modules' can do two things that can’t
be done directly in Python: they can implement new built-in object
types, and they can call C library functions and system calls.

To support extensions, the Python API (Application Programmers
Interface) defines a set of functions, macros and variables that provide
access to most aspects of the Python run-time system.  The Python API is
incorporated in a C source file by including the header ‘"Python.h"’.

The compilation of an extension module depends on its intended use as
well as on your system setup; details are given in later chapters.

     Note: The C extension interface is specific to CPython, and
     extension modules do not work on other Python implementations.  In
     many cases, it is possible to avoid writing C extensions and
     preserve portability to other implementations.  For example, if
     your use case is calling C library functions or system calls, you
     should consider using the *note ctypes: 2a. module or the cffi(1)
     library rather than writing custom C code.  These modules let you
     write Python code to interface with C code and are more portable
     between implementations of Python than writing and compiling a C
     extension module.

* Menu:

* A Simple Example::
* Intermezzo; Errors and Exceptions: Intermezzo Errors and Exceptions.
* Back to the Example::
* The Module’s Method Table and Initialization Function::
* Compilation and Linkage::
* Calling Python Functions from C::
* Extracting Parameters in Extension Functions::
* Keyword Parameters for Extension Functions::
* Building Arbitrary Values::
* Reference Counts::
* Writing Extensions in C++::
* Providing a C API for an Extension Module::

   ---------- Footnotes ----------

   (1) https://cffi.readthedocs.io/


File: python.info,  Node: A Simple Example,  Next: Intermezzo Errors and Exceptions,  Up: Extending Python with C or C++

6.2.1.1 A Simple Example
........................

Let’s create an extension module called ‘spam’ (the favorite food of
Monty Python fans…) and let’s say we want to create a Python interface
to the C library function ‘system()’ (1).  This function takes a
null-terminated character string as argument and returns an integer.  We
want this function to be callable from Python as follows:

     >>> import spam
     >>> status = spam.system("ls -l")

Begin by creating a file ‘spammodule.c’.  (Historically, if a module is
called ‘spam’, the C file containing its implementation is called
‘spammodule.c’; if the module name is very long, like ‘spammify’, the
module name can be just ‘spammify.c’.)

The first two lines of our file can be:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

which pulls in the Python API (you can add a comment describing the
purpose of the module and a copyright notice if you like).

     Note: Since Python may define some pre-processor definitions which
     affect the standard headers on some systems, you 'must' include
     ‘Python.h’ before any standard headers are included.

     ‘#define PY_SSIZE_T_CLEAN’ was used to indicate that ‘Py_ssize_t’
     should be used in some APIs instead of ‘int’.  It is not necessary
     since Python 3.13, but we keep it here for backward compatibility.
     See *note Strings and buffers: 38e. for a description of this
     macro.

All user-visible symbols defined by ‘Python.h’ have a prefix of ‘Py’ or
‘PY’, except those defined in standard header files.

     Tip: For backward compatibility, ‘Python.h’ includes several
     standard header files.  C extensions should include the standard
     headers that they use, and should not rely on these implicit
     includes.  If using the limited C API version 3.13 or newer, the
     implicit includes are:

        * ‘<assert.h>’

        * ‘<intrin.h>’ (on Windows)

        * ‘<inttypes.h>’

        * ‘<limits.h>’

        * ‘<math.h>’

        * ‘<stdarg.h>’

        * ‘<wchar.h>’

        * ‘<sys/types.h>’ (if present)

     If *note Py_LIMITED_API: 421. is not defined, or is set to version
     3.12 or older, the headers below are also included:

        * ‘<ctype.h>’

        * ‘<unistd.h>’ (on POSIX)

     If *note Py_LIMITED_API: 421. is not defined, or is set to version
     3.10 or older, the headers below are also included:

        * ‘<errno.h>’

        * ‘<stdio.h>’

        * ‘<stdlib.h>’

        * ‘<string.h>’

The next thing we add to our module file is the C function that will be
called when the Python expression ‘spam.system(string)’ is evaluated
(we’ll see shortly how it ends up being called):

     static PyObject *
     spam_system(PyObject *self, PyObject *args)
     {
         const char *command;
         int sts;

         if (!PyArg_ParseTuple(args, "s", &command))
             return NULL;
         sts = system(command);
         return PyLong_FromLong(sts);
     }

There is a straightforward translation from the argument list in Python
(for example, the single expression ‘"ls -l"’) to the arguments passed
to the C function.  The C function always has two arguments,
conventionally named 'self' and 'args'.

The 'self' argument points to the module object for module-level
functions; for a method it would point to the object instance.

The 'args' argument will be a pointer to a Python tuple object
containing the arguments.  Each item of the tuple corresponds to an
argument in the call’s argument list.  The arguments are Python objects
— in order to do anything with them in our C function we have to convert
them to C values.  The function *note PyArg_ParseTuple(): 574. in the
Python API checks the argument types and converts them to C values.  It
uses a template string to determine the required types of the arguments
as well as the types of the C variables into which to store the
converted values.  More about this later.

*note PyArg_ParseTuple(): 574. returns true (nonzero) if all arguments
have the right type and its components have been stored in the variables
whose addresses are passed.  It returns false (zero) if an invalid
argument list was passed.  In the latter case it also raises an
appropriate exception so the calling function can return ‘NULL’
immediately (as we saw in the example).

   ---------- Footnotes ----------

   (1) An interface for this function already exists in the standard
module *note os: a1. — it was chosen as a simple and straightforward
example.


File: python.info,  Node: Intermezzo Errors and Exceptions,  Next: Back to the Example,  Prev: A Simple Example,  Up: Extending Python with C or C++

6.2.1.2 Intermezzo: Errors and Exceptions
.........................................

An important convention throughout the Python interpreter is the
following: when a function fails, it should set an exception condition
and return an error value (usually ‘-1’ or a ‘NULL’ pointer).  Exception
information is stored in three members of the interpreter’s thread
state.  These are ‘NULL’ if there is no exception.  Otherwise they are
the C equivalents of the members of the Python tuple returned by *note
sys.exc_info(): 68d.  These are the exception type, exception instance,
and a traceback object.  It is important to know about them to
understand how errors are passed around.

The Python API defines a number of functions to set various types of
exceptions.

The most common one is *note PyErr_SetString(): 57f.  Its arguments are
an exception object and a C string.  The exception object is usually a
predefined object like *note PyExc_ZeroDivisionError: 4b61.  The C
string indicates the cause of the error and is converted to a Python
string object and stored as the “associated value” of the exception.

Another useful function is *note PyErr_SetFromErrno(): 4b62, which only
takes an exception argument and constructs the associated value by
inspection of the global variable ‘errno’.  The most general function is
*note PyErr_SetObject(): 57e, which takes two object arguments, the
exception and its associated value.  You don’t need to *note
Py_INCREF(): 571. the objects passed to any of these functions.

You can test non-destructively whether an exception has been set with
*note PyErr_Occurred(): 1a55.  This returns the current exception
object, or ‘NULL’ if no exception has occurred.  You normally don’t need
to call ‘PyErr_Occurred()’ to see whether an error occurred in a
function call, since you should be able to tell from the return value.

When a function 'f' that calls another function 'g' detects that the
latter fails, 'f' should itself return an error value (usually ‘NULL’ or
‘-1’).  It should 'not' call one of the ‘PyErr_*’ functions — one has
already been called by 'g'.  'f'’s caller is then supposed to also
return an error indication to 'its' caller, again 'without' calling
‘PyErr_*’, and so on — the most detailed cause of the error was already
reported by the function that first detected it.  Once the error reaches
the Python interpreter’s main loop, this aborts the currently executing
Python code and tries to find an exception handler specified by the
Python programmer.

(There are situations where a module can actually give a more detailed
error message by calling another ‘PyErr_*’ function, and in such cases
it is fine to do so.  As a general rule, however, this is not necessary,
and can cause information about the cause of the error to be lost: most
operations can fail for a variety of reasons.)

To ignore an exception set by a function call that failed, the exception
condition must be cleared explicitly by calling *note PyErr_Clear():
106e.  The only time C code should call ‘PyErr_Clear()’ is if it doesn’t
want to pass the error on to the interpreter but wants to handle it
completely by itself (possibly by trying something else, or pretending
nothing went wrong).

Every failing ‘malloc()’ call must be turned into an exception — the
direct caller of ‘malloc()’ (or ‘realloc()’) must call *note
PyErr_NoMemory(): 4b63. and return a failure indicator itself.  All the
object-creating functions (for example, *note PyLong_FromLong(): 1975.)
already do this, so this note is only relevant to those who call
‘malloc()’ directly.

Also note that, with the important exception of *note
PyArg_ParseTuple(): 574. and friends, functions that return an integer
status usually return a positive value or zero for success and ‘-1’ for
failure, like Unix system calls.

Finally, be careful to clean up garbage (by making *note Py_XDECREF():
792. or *note Py_DECREF(): 572. calls for objects you have already
created) when you return an error indicator!

The choice of which exception to raise is entirely yours.  There are
predeclared C objects corresponding to all built-in Python exceptions,
such as *note PyExc_ZeroDivisionError: 4b61, which you can use directly.
Of course, you should choose exceptions wisely — don’t use *note
PyExc_TypeError: 4b64. to mean that a file couldn’t be opened (that
should probably be *note PyExc_OSError: 4b65.).  If something’s wrong
with the argument list, the *note PyArg_ParseTuple(): 574. function
usually raises ‘PyExc_TypeError’.  If you have an argument whose value
must be in a particular range or must satisfy other conditions, *note
PyExc_ValueError: 4b66. is appropriate.

You can also define a new exception that is unique to your module.  The
simplest way to do this is to declare a static global object variable at
the beginning of the file:

     static PyObject *SpamError = NULL;

and initialize it by calling *note PyErr_NewException(): 12b0. in the
module’s *note Py_mod_exec: 988. function (‘spam_module_exec()’):

     SpamError = PyErr_NewException("spam.error", NULL, NULL);

Since ‘SpamError’ is a global variable, it will be overwritten every
time the module is reinitialized, when the *note Py_mod_exec: 988.
function is called.

For now, let’s avoid the issue: we will block repeated initialization by
raising an *note ImportError: 41c.:

     static PyObject *SpamError = NULL;

     static int
     spam_module_exec(PyObject *m)
     {
         if (SpamError != NULL) {
             PyErr_SetString(PyExc_ImportError,
                             "cannot initialize spam module more than once");
             return -1;
         }
         SpamError = PyErr_NewException("spam.error", NULL, NULL);
         if (PyModule_AddObjectRef(m, "SpamError", SpamError) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot spam_module_slots[] = {
         {Py_mod_exec, spam_module_exec},
         {0, NULL}
     };

     static struct PyModuleDef spam_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "spam",
         .m_size = 0,  // non-negative
         .m_slots = spam_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_spam(void)
     {
         return PyModuleDef_Init(&spam_module);
     }

Note that the Python name for the exception object is ‘spam.error’.  The
*note PyErr_NewException(): 12b0. function may create a class with the
base class being *note Exception: 9e5. (unless another class is passed
in instead of ‘NULL’), described in *note Built-in Exceptions: 19cc.

Note also that the ‘SpamError’ variable retains a reference to the newly
created exception class; this is intentional!  Since the exception could
be removed from the module by external code, an owned reference to the
class is needed to ensure that it will not be discarded, causing
‘SpamError’ to become a dangling pointer.  Should it become a dangling
pointer, C code which raises the exception could cause a core dump or
other unintended side effects.

For now, the *note Py_DECREF(): 572. call to remove this reference is
missing.  Even when the Python interpreter shuts down, the global
‘SpamError’ variable will not be garbage-collected.  It will “leak”.  We
did, however, ensure that this will happen at most once per process.

We discuss the use of *note PyMODINIT_FUNC: 1522. as a function return
type later in this sample.

The ‘spam.error’ exception can be raised in your extension module using
a call to *note PyErr_SetString(): 57f. as shown below:

     static PyObject *
     spam_system(PyObject *self, PyObject *args)
     {
         const char *command;
         int sts;

         if (!PyArg_ParseTuple(args, "s", &command))
             return NULL;
         sts = system(command);
         if (sts < 0) {
             PyErr_SetString(SpamError, "System command failed");
             return NULL;
         }
         return PyLong_FromLong(sts);
     }


File: python.info,  Node: Back to the Example,  Next: The Module’s Method Table and Initialization Function,  Prev: Intermezzo Errors and Exceptions,  Up: Extending Python with C or C++

6.2.1.3 Back to the Example
...........................

Going back to our example function, you should now be able to understand
this statement:

     if (!PyArg_ParseTuple(args, "s", &command))
         return NULL;

It returns ‘NULL’ (the error indicator for functions returning object
pointers) if an error is detected in the argument list, relying on the
exception set by *note PyArg_ParseTuple(): 574.  Otherwise the string
value of the argument has been copied to the local variable ‘command’.
This is a pointer assignment and you are not supposed to modify the
string to which it points (so in Standard C, the variable ‘command’
should properly be declared as ‘const char *command’).

The next statement is a call to the Unix function ‘system()’, passing it
the string we just got from *note PyArg_ParseTuple(): 574.:

     sts = system(command);

Our ‘spam.system()’ function must return the value of ‘sts’ as a Python
object.  This is done using the function *note PyLong_FromLong(): 1975.

     return PyLong_FromLong(sts);

In this case, it will return an integer object.  (Yes, even integers are
objects on the heap in Python!)

If you have a C function that returns no useful argument (a function
returning void), the corresponding Python function must return ‘None’.
You need this idiom to do so (which is implemented by the *note
Py_RETURN_NONE: 14c2. macro):

     Py_INCREF(Py_None);
     return Py_None;

*note Py_None: 4b69. is the C name for the special Python object ‘None’.
It is a genuine Python object rather than a ‘NULL’ pointer, which means
“error” in most contexts, as we have seen.


File: python.info,  Node: The Module’s Method Table and Initialization Function,  Next: Compilation and Linkage,  Prev: Back to the Example,  Up: Extending Python with C or C++

6.2.1.4 The Module’s Method Table and Initialization Function
.............................................................

I promised to show how ‘spam_system()’ is called from Python programs.
First, we need to list its name and address in a “method table”:

     static PyMethodDef spam_methods[] = {
         ...
         {"system",  spam_system, METH_VARARGS,
          "Execute a shell command."},
         ...
         {NULL, NULL, 0, NULL}        /* Sentinel */
     };

Note the third entry (‘METH_VARARGS’).  This is a flag telling the
interpreter the calling convention to be used for the C function.  It
should normally always be ‘METH_VARARGS’ or ‘METH_VARARGS |
METH_KEYWORDS’; a value of ‘0’ means that an obsolete variant of *note
PyArg_ParseTuple(): 574. is used.

When using only ‘METH_VARARGS’, the function should expect the
Python-level parameters to be passed in as a tuple acceptable for
parsing via *note PyArg_ParseTuple(): 574.; more information on this
function is provided below.

The *note METH_KEYWORDS: 4b6c. bit may be set in the third field if
keyword arguments should be passed to the function.  In this case, the C
function should accept a third ‘PyObject *’ parameter which will be a
dictionary of keywords.  Use *note PyArg_ParseTupleAndKeywords(): 386.
to parse the arguments to such a function.

The method table must be referenced in the module definition structure:

     static struct PyModuleDef spam_module = {
         ...
         .m_methods = spam_methods,
         ...
     };

This structure, in turn, must be passed to the interpreter in the
module’s initialization function.  The initialization function must be
named ‘PyInit_name()’, where 'name' is the name of the module, and
should be the only non-‘static’ item defined in the module file:

     PyMODINIT_FUNC
     PyInit_spam(void)
     {
         return PyModuleDef_Init(&spam_module);
     }

Note that *note PyMODINIT_FUNC: 1522. declares the function as ‘PyObject
*’ return type, declares any special linkage declarations required by
the platform, and for C++ declares the function as ‘extern "C"’.

‘PyInit_spam()’ is called when each interpreter imports its module
‘spam’ for the first time.  (See below for comments about embedding
Python.)  A pointer to the module definition must be returned via *note
PyModuleDef_Init(): 4b6d, so that the import machinery can create the
module and store it in ‘sys.modules’.

When embedding Python, the ‘PyInit_spam()’ function is not called
automatically unless there’s an entry in the *note PyImport_Inittab:
18be. table.  To add the module to the initialization table, use *note
PyImport_AppendInittab(): 18bf, optionally followed by an import of the
module:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     int
     main(int argc, char *argv[])
     {
         PyStatus status;
         PyConfig config;
         PyConfig_InitPythonConfig(&config);

         /* Add a built-in module, before Py_Initialize */
         if (PyImport_AppendInittab("spam", PyInit_spam) == -1) {
             fprintf(stderr, "Error: could not extend in-built modules table\n");
             exit(1);
         }

         /* Pass argv[0] to the Python interpreter */
         status = PyConfig_SetBytesString(&config, &config.program_name, argv[0]);
         if (PyStatus_Exception(status)) {
             goto exception;
         }

         /* Initialize the Python interpreter.  Required.
            If this step fails, it will be a fatal error. */
         status = Py_InitializeFromConfig(&config);
         if (PyStatus_Exception(status)) {
             goto exception;
         }
         PyConfig_Clear(&config);

         /* Optionally import the module; alternatively,
            import can be deferred until the embedded script
            imports it. */
         PyObject *pmodule = PyImport_ImportModule("spam");
         if (!pmodule) {
             PyErr_Print();
             fprintf(stderr, "Error: could not import module 'spam'\n");
         }

         // ... use Python C API here ...

         return 0;

       exception:
          PyConfig_Clear(&config);
          Py_ExitStatusException(status);
     }

     Note: If you declare a global variable or a local static one, the
     module may experience unintended side-effects on re-initialisation,
     for example when removing entries from ‘sys.modules’ or importing
     compiled modules into multiple interpreters within a process (or
     following a ‘fork()’ without an intervening ‘exec()’).  If module
     state is not yet fully *note isolated: 4b6e, authors should
     consider marking the module as having no support for
     subinterpreters (via *note
     Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED: 4b6f.).

A more substantial example module is included in the Python source
distribution as ‘Modules/xxlimited.c’.  This file may be used as a
template or simply read as an example.


File: python.info,  Node: Compilation and Linkage,  Next: Calling Python Functions from C,  Prev: The Module’s Method Table and Initialization Function,  Up: Extending Python with C or C++

6.2.1.5 Compilation and Linkage
...............................

There are two more things to do before you can use your new extension:
compiling and linking it with the Python system.  If you use dynamic
loading, the details may depend on the style of dynamic loading your
system uses; see the chapters about building extension modules (chapter
*note Building C and C++ Extensions: 4b72.) and additional information
that pertains only to building on Windows (chapter *note Building C and
C++ Extensions on Windows: 1fde.) for more information about this.

If you can’t use dynamic loading, or if you want to make your module a
permanent part of the Python interpreter, you will have to change the
configuration setup and rebuild the interpreter.  Luckily, this is very
simple on Unix: just place your file (‘spammodule.c’ for example) in the
‘Modules/’ directory of an unpacked source distribution, add a line to
the file ‘Modules/Setup.local’ describing your file:

     spam spammodule.o

and rebuild the interpreter by running ‘make’ in the toplevel directory.
You can also run ‘make’ in the ‘Modules/’ subdirectory, but then you
must first rebuild ‘Makefile’ there by running ‘‘make’ Makefile’.  (This
is necessary each time you change the ‘Setup’ file.)

If your module requires additional libraries to link with, these can be
listed on the line in the configuration file as well, for instance:

     spam spammodule.o -lX11


File: python.info,  Node: Calling Python Functions from C,  Next: Extracting Parameters in Extension Functions,  Prev: Compilation and Linkage,  Up: Extending Python with C or C++

6.2.1.6 Calling Python Functions from C
.......................................

So far we have concentrated on making C functions callable from Python.
The reverse is also useful: calling Python functions from C. This is
especially the case for libraries that support so-called “callback”
functions.  If a C interface makes use of callbacks, the equivalent
Python often needs to provide a callback mechanism to the Python
programmer; the implementation will require calling the Python callback
functions from a C callback.  Other uses are also imaginable.

Fortunately, the Python interpreter is easily called recursively, and
there is a standard interface to call a Python function.  (I won’t dwell
on how to call the Python parser with a particular string as input — if
you’re interested, have a look at the implementation of the *note -c:
5e3. command line option in ‘Modules/main.c’ from the Python source
code.)

Calling a Python function is easy.  First, the Python program must
somehow pass you the Python function object.  You should provide a
function (or some other interface) to do this.  When this function is
called, save a pointer to the Python function object (be careful to
*note Py_INCREF(): 571. it!)  in a global variable — or wherever you see
fit.  For example, the following function might be part of a module
definition:

     static PyObject *my_callback = NULL;

     static PyObject *
     my_set_callback(PyObject *dummy, PyObject *args)
     {
         PyObject *result = NULL;
         PyObject *temp;

         if (PyArg_ParseTuple(args, "O:set_callback", &temp)) {
             if (!PyCallable_Check(temp)) {
                 PyErr_SetString(PyExc_TypeError, "parameter must be callable");
                 return NULL;
             }
             Py_XINCREF(temp);         /* Add a reference to new callback */
             Py_XDECREF(my_callback);  /* Dispose of previous callback */
             my_callback = temp;       /* Remember new callback */
             /* Boilerplate to return "None" */
             Py_INCREF(Py_None);
             result = Py_None;
         }
         return result;
     }

This function must be registered with the interpreter using the *note
METH_VARARGS: 1558. flag; this is described in section *note The
Module’s Method Table and Initialization Function: 4b6a.  The *note
PyArg_ParseTuple(): 574. function and its arguments are documented in
section *note Extracting Parameters in Extension Functions: 4b75.

The macros *note Py_XINCREF(): a73. and *note Py_XDECREF(): 792.
increment/decrement the reference count of an object and are safe in the
presence of ‘NULL’ pointers (but note that 'temp' will not be ‘NULL’ in
this context).  More info on them in section *note Reference Counts:
4b76.

Later, when it is time to call the function, you call the C function
*note PyObject_CallObject(): 4b77.  This function has two arguments,
both pointers to arbitrary Python objects: the Python function, and the
argument list.  The argument list must always be a tuple object, whose
length is the number of arguments.  To call the Python function with no
arguments, pass in ‘NULL’, or an empty tuple; to call it with one
argument, pass a singleton tuple.  *note Py_BuildValue(): 8af. returns a
tuple when its format string consists of zero or more format codes
between parentheses.  For example:

     int arg;
     PyObject *arglist;
     PyObject *result;
     ...
     arg = 123;
     ...
     /* Time to call the callback */
     arglist = Py_BuildValue("(i)", arg);
     result = PyObject_CallObject(my_callback, arglist);
     Py_DECREF(arglist);

*note PyObject_CallObject(): 4b77. returns a Python object pointer: this
is the return value of the Python function.  ‘PyObject_CallObject()’ is
“reference-count-neutral” with respect to its arguments.  In the example
a new tuple was created to serve as the argument list, which is *note
Py_DECREF(): 572.-ed immediately after the ‘PyObject_CallObject()’ call.

The return value of *note PyObject_CallObject(): 4b77. is “new”: either
it is a brand new object, or it is an existing object whose reference
count has been incremented.  So, unless you want to save it in a global
variable, you should somehow *note Py_DECREF(): 572. the result, even
(especially!)  if you are not interested in its value.

Before you do this, however, it is important to check that the return
value isn’t ‘NULL’.  If it is, the Python function terminated by raising
an exception.  If the C code that called *note PyObject_CallObject():
4b77. is called from Python, it should now return an error indication to
its Python caller, so the interpreter can print a stack trace, or the
calling Python code can handle the exception.  If this is not possible
or desirable, the exception should be cleared by calling *note
PyErr_Clear(): 106e.  For example:

     if (result == NULL)
         return NULL; /* Pass error back */
     ...use result...
     Py_DECREF(result);

Depending on the desired interface to the Python callback function, you
may also have to provide an argument list to *note
PyObject_CallObject(): 4b77.  In some cases the argument list is also
provided by the Python program, through the same interface that
specified the callback function.  It can then be saved and used in the
same manner as the function object.  In other cases, you may have to
construct a new tuple to pass as the argument list.  The simplest way to
do this is to call *note Py_BuildValue(): 8af.  For example, if you want
to pass an integral event code, you might use the following code:

     PyObject *arglist;
     ...
     arglist = Py_BuildValue("(l)", eventcode);
     result = PyObject_CallObject(my_callback, arglist);
     Py_DECREF(arglist);
     if (result == NULL)
         return NULL; /* Pass error back */
     /* Here maybe use the result */
     Py_DECREF(result);

Note the placement of ‘Py_DECREF(arglist)’ immediately after the call,
before the error check!  Also note that strictly speaking this code is
not complete: *note Py_BuildValue(): 8af. may run out of memory, and
this should be checked.

You may also call a function with keyword arguments by using *note
PyObject_Call(): 39f, which supports arguments and keyword arguments.
As in the above example, we use *note Py_BuildValue(): 8af. to construct
the dictionary.

     PyObject *dict;
     ...
     dict = Py_BuildValue("{s:i}", "name", val);
     result = PyObject_Call(my_callback, NULL, dict);
     Py_DECREF(dict);
     if (result == NULL)
         return NULL; /* Pass error back */
     /* Here maybe use the result */
     Py_DECREF(result);


File: python.info,  Node: Extracting Parameters in Extension Functions,  Next: Keyword Parameters for Extension Functions,  Prev: Calling Python Functions from C,  Up: Extending Python with C or C++

6.2.1.7 Extracting Parameters in Extension Functions
....................................................

The *note PyArg_ParseTuple(): 574. function is declared as follows:

     int PyArg_ParseTuple(PyObject *arg, const char *format, ...);

The 'arg' argument must be a tuple object containing an argument list
passed from Python to a C function.  The 'format' argument must be a
format string, whose syntax is explained in *note Parsing arguments and
building values: 8b0. in the Python/C API Reference Manual.  The
remaining arguments must be addresses of variables whose type is
determined by the format string.

Note that while *note PyArg_ParseTuple(): 574. checks that the Python
arguments have the required types, it cannot check the validity of the
addresses of C variables passed to the call: if you make mistakes there,
your code will probably crash or at least overwrite random bits in
memory.  So be careful!

Note that any Python object references which are provided to the caller
are 'borrowed' references; do not decrement their reference count!

Some example calls:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     int ok;
     int i, j;
     long k, l;
     const char *s;
     Py_ssize_t size;

     ok = PyArg_ParseTuple(args, ""); /* No arguments */
         /* Python call: f() */

     ok = PyArg_ParseTuple(args, "s", &s); /* A string */
         /* Possible Python call: f('whoops!') */

     ok = PyArg_ParseTuple(args, "lls", &k, &l, &s); /* Two longs and a string */
         /* Possible Python call: f(1, 2, 'three') */

     ok = PyArg_ParseTuple(args, "(ii)s#", &i, &j, &s, &size);
         /* A pair of ints and a string, whose size is also returned */
         /* Possible Python call: f((1, 2), 'three') */

     {
         const char *file;
         const char *mode = "r";
         int bufsize = 0;
         ok = PyArg_ParseTuple(args, "s|si", &file, &mode, &bufsize);
         /* A string, and optionally another string and an integer */
         /* Possible Python calls:
            f('spam')
            f('spam', 'w')
            f('spam', 'wb', 100000) */
     }

     {
         int left, top, right, bottom, h, v;
         ok = PyArg_ParseTuple(args, "((ii)(ii))(ii)",
                  &left, &top, &right, &bottom, &h, &v);
         /* A rectangle and a point */
         /* Possible Python call:
            f(((0, 0), (400, 300)), (10, 10)) */
     }

     {
         Py_complex c;
         ok = PyArg_ParseTuple(args, "D:myfunction", &c);
         /* a complex, also providing a function name for errors */
         /* Possible Python call: myfunction(1+2j) */
     }


File: python.info,  Node: Keyword Parameters for Extension Functions,  Next: Building Arbitrary Values,  Prev: Extracting Parameters in Extension Functions,  Up: Extending Python with C or C++

6.2.1.8 Keyword Parameters for Extension Functions
..................................................

The *note PyArg_ParseTupleAndKeywords(): 386. function is declared as
follows:

     int PyArg_ParseTupleAndKeywords(PyObject *arg, PyObject *kwdict,
                                     const char *format, char * const *kwlist, ...);

The 'arg' and 'format' parameters are identical to those of the *note
PyArg_ParseTuple(): 574. function.  The 'kwdict' parameter is the
dictionary of keywords received as the third parameter from the Python
runtime.  The 'kwlist' parameter is a ‘NULL’-terminated list of strings
which identify the parameters; the names are matched with the type
information from 'format' from left to right.  On success, *note
PyArg_ParseTupleAndKeywords(): 386. returns true, otherwise it returns
false and raises an appropriate exception.

     Note: Nested tuples cannot be parsed when using keyword arguments!
     Keyword parameters passed in which are not present in the 'kwlist'
     will cause *note TypeError: 2c3. to be raised.

Here is an example module which uses keywords, based on an example by
Geoff Philbrick (<philbrick@hks.com>):

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     static PyObject *
     keywdarg_parrot(PyObject *self, PyObject *args, PyObject *keywds)
     {
         int voltage;
         const char *state = "a stiff";
         const char *action = "voom";
         const char *type = "Norwegian Blue";

         static char *kwlist[] = {"voltage", "state", "action", "type", NULL};

         if (!PyArg_ParseTupleAndKeywords(args, keywds, "i|sss", kwlist,
                                          &voltage, &state, &action, &type))
             return NULL;

         printf("-- This parrot wouldn't %s if you put %i Volts through it.\n",
                action, voltage);
         printf("-- Lovely plumage, the %s -- It's %s!\n", type, state);

         Py_RETURN_NONE;
     }

     static PyMethodDef keywdarg_methods[] = {
         /* The cast of the function is necessary since PyCFunction values
          * only take two PyObject* parameters, and keywdarg_parrot() takes
          * three.
          */
         {"parrot", (PyCFunction)(void(*)(void))keywdarg_parrot, METH_VARARGS | METH_KEYWORDS,
          "Print a lovely skit to standard output."},
         {NULL, NULL, 0, NULL}   /* sentinel */
     };

     static struct PyModuleDef keywdarg_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "keywdarg",
         .m_size = 0,
         .m_methods = keywdarg_methods,
     };

     PyMODINIT_FUNC
     PyInit_keywdarg(void)
     {
         return PyModuleDef_Init(&keywdarg_module);
     }


File: python.info,  Node: Building Arbitrary Values,  Next: Reference Counts,  Prev: Keyword Parameters for Extension Functions,  Up: Extending Python with C or C++

6.2.1.9 Building Arbitrary Values
.................................

This function is the counterpart to *note PyArg_ParseTuple(): 574.  It
is declared as follows:

     PyObject *Py_BuildValue(const char *format, ...);

It recognizes a set of format units similar to the ones recognized by
*note PyArg_ParseTuple(): 574, but the arguments (which are input to the
function, not output) must not be pointers, just values.  It returns a
new Python object, suitable for returning from a C function called from
Python.

One difference with *note PyArg_ParseTuple(): 574.: while the latter
requires its first argument to be a tuple (since Python argument lists
are always represented as tuples internally), *note Py_BuildValue():
8af. does not always build a tuple.  It builds a tuple only if its
format string contains two or more format units.  If the format string
is empty, it returns ‘None’; if it contains exactly one format unit, it
returns whatever object is described by that format unit.  To force it
to return a tuple of size 0 or one, parenthesize the format string.

Examples (to the left the call, to the right the resulting Python
value):

     Py_BuildValue("")                        None
     Py_BuildValue("i", 123)                  123
     Py_BuildValue("iii", 123, 456, 789)      (123, 456, 789)
     Py_BuildValue("s", "hello")              'hello'
     Py_BuildValue("y", "hello")              b'hello'
     Py_BuildValue("ss", "hello", "world")    ('hello', 'world')
     Py_BuildValue("s#", "hello", 4)          'hell'
     Py_BuildValue("y#", "hello", 4)          b'hell'
     Py_BuildValue("()")                      ()
     Py_BuildValue("(i)", 123)                (123,)
     Py_BuildValue("(ii)", 123, 456)          (123, 456)
     Py_BuildValue("(i,i)", 123, 456)         (123, 456)
     Py_BuildValue("[i,i]", 123, 456)         [123, 456]
     Py_BuildValue("{s:i,s:i}",
                   "abc", 123, "def", 456)    {'abc': 123, 'def': 456}
     Py_BuildValue("((ii)(ii)) (ii)",
                   1, 2, 3, 4, 5, 6)          (((1, 2), (3, 4)), (5, 6))


File: python.info,  Node: Reference Counts,  Next: Writing Extensions in C++,  Prev: Building Arbitrary Values,  Up: Extending Python with C or C++

6.2.1.10 Reference Counts
.........................

In languages like C or C++, the programmer is responsible for dynamic
allocation and deallocation of memory on the heap.  In C, this is done
using the functions ‘malloc()’ and ‘free()’.  In C++, the operators
‘new’ and ‘delete’ are used with essentially the same meaning and we’ll
restrict the following discussion to the C case.

Every block of memory allocated with ‘malloc()’ should eventually be
returned to the pool of available memory by exactly one call to
‘free()’.  It is important to call ‘free()’ at the right time.  If a
block’s address is forgotten but ‘free()’ is not called for it, the
memory it occupies cannot be reused until the program terminates.  This
is called a 'memory leak'.  On the other hand, if a program calls
‘free()’ for a block and then continues to use the block, it creates a
conflict with reuse of the block through another ‘malloc()’ call.  This
is called 'using freed memory'.  It has the same bad consequences as
referencing uninitialized data — core dumps, wrong results, mysterious
crashes.

Common causes of memory leaks are unusual paths through the code.  For
instance, a function may allocate a block of memory, do some
calculation, and then free the block again.  Now a change in the
requirements for the function may add a test to the calculation that
detects an error condition and can return prematurely from the function.
It’s easy to forget to free the allocated memory block when taking this
premature exit, especially when it is added later to the code.  Such
leaks, once introduced, often go undetected for a long time: the error
exit is taken only in a small fraction of all calls, and most modern
machines have plenty of virtual memory, so the leak only becomes
apparent in a long-running process that uses the leaking function
frequently.  Therefore, it’s important to prevent leaks from happening
by having a coding convention or strategy that minimizes this kind of
errors.

Since Python makes heavy use of ‘malloc()’ and ‘free()’, it needs a
strategy to avoid memory leaks as well as the use of freed memory.  The
chosen method is called 'reference counting'.  The principle is simple:
every object contains a counter, which is incremented when a reference
to the object is stored somewhere, and which is decremented when a
reference to it is deleted.  When the counter reaches zero, the last
reference to the object has been deleted and the object is freed.

An alternative strategy is called 'automatic garbage collection'.
(Sometimes, reference counting is also referred to as a garbage
collection strategy, hence my use of “automatic” to distinguish the
two.)  The big advantage of automatic garbage collection is that the
user doesn’t need to call ‘free()’ explicitly.  (Another claimed
advantage is an improvement in speed or memory usage — this is no hard
fact however.)  The disadvantage is that for C, there is no truly
portable automatic garbage collector, while reference counting can be
implemented portably (as long as the functions ‘malloc()’ and ‘free()’
are available — which the C Standard guarantees).  Maybe some day a
sufficiently portable automatic garbage collector will be available for
C. Until then, we’ll have to live with reference counts.

While Python uses the traditional reference counting implementation, it
also offers a cycle detector that works to detect reference cycles.
This allows applications to not worry about creating direct or indirect
circular references; these are the weakness of garbage collection
implemented using only reference counting.  Reference cycles consist of
objects which contain (possibly indirect) references to themselves, so
that each object in the cycle has a reference count which is non-zero.
Typical reference counting implementations are not able to reclaim the
memory belonging to any objects in a reference cycle, or referenced from
the objects in the cycle, even though there are no further references to
the cycle itself.

The cycle detector is able to detect garbage cycles and can reclaim
them.  The *note gc: 60. module exposes a way to run the detector (the
*note collect(): a47. function), as well as configuration interfaces and
the ability to disable the detector at runtime.

* Menu:

* Reference Counting in Python::
* Ownership Rules::
* Thin Ice::
* NULL Pointers::


File: python.info,  Node: Reference Counting in Python,  Next: Ownership Rules,  Up: Reference Counts

6.2.1.11 Reference Counting in Python
.....................................

There are two macros, ‘Py_INCREF(x)’ and ‘Py_DECREF(x)’, which handle
the incrementing and decrementing of the reference count.  *note
Py_DECREF(): 572. also frees the object when the count reaches zero.
For flexibility, it doesn’t call ‘free()’ directly — rather, it makes a
call through a function pointer in the object’s 'type object'.  For this
purpose (and others), every object also contains a pointer to its type
object.

The big question now remains: when to use ‘Py_INCREF(x)’ and
‘Py_DECREF(x)’?  Let’s first introduce some terms.  Nobody “owns” an
object; however, you can 'own a reference' to an object.  An object’s
reference count is now defined as the number of owned references to it.
The owner of a reference is responsible for calling *note Py_DECREF():
572. when the reference is no longer needed.  Ownership of a reference
can be transferred.  There are three ways to dispose of an owned
reference: pass it on, store it, or call ‘Py_DECREF()’.  Forgetting to
dispose of an owned reference creates a memory leak.

It is also possible to 'borrow' (1) a reference to an object.  The
borrower of a reference should not call *note Py_DECREF(): 572.  The
borrower must not hold on to the object longer than the owner from which
it was borrowed.  Using a borrowed reference after the owner has
disposed of it risks using freed memory and should be avoided completely
(2).

The advantage of borrowing over owning a reference is that you don’t
need to take care of disposing of the reference on all possible paths
through the code — in other words, with a borrowed reference you don’t
run the risk of leaking when a premature exit is taken.  The
disadvantage of borrowing over owning is that there are some subtle
situations where in seemingly correct code a borrowed reference can be
used after the owner from which it was borrowed has in fact disposed of
it.

A borrowed reference can be changed into an owned reference by calling
*note Py_INCREF(): 571.  This does not affect the status of the owner
from which the reference was borrowed — it creates a new owned
reference, and gives full owner responsibilities (the new owner must
dispose of the reference properly, as well as the previous owner).

   ---------- Footnotes ----------

   (1) The metaphor of “borrowing” a reference is not completely
correct: the owner still has a copy of the reference.

   (2) Checking that the reference count is at least 1 'does not work' —
the reference count itself could be in freed memory and may thus be
reused for another object!


File: python.info,  Node: Ownership Rules,  Next: Thin Ice,  Prev: Reference Counting in Python,  Up: Reference Counts

6.2.1.12 Ownership Rules
........................

Whenever an object reference is passed into or out of a function, it is
part of the function’s interface specification whether ownership is
transferred with the reference or not.

Most functions that return a reference to an object pass on ownership
with the reference.  In particular, all functions whose function it is
to create a new object, such as *note PyLong_FromLong(): 1975. and *note
Py_BuildValue(): 8af, pass ownership to the receiver.  Even if the
object is not actually new, you still receive ownership of a new
reference to that object.  For instance, ‘PyLong_FromLong()’ maintains a
cache of popular values and can return a reference to a cached item.

Many functions that extract objects from other objects also transfer
ownership with the reference, for instance *note
PyObject_GetAttrString(): 34d.  The picture is less clear, here,
however, since a few common routines are exceptions: *note
PyTuple_GetItem(): 4b82, *note PyList_GetItem(): 35d, *note
PyDict_GetItem(): 38a, and *note PyDict_GetItemString(): 38b. all return
references that you borrow from the tuple, list or dictionary.

The function *note PyImport_AddModule(): 35a. also returns a borrowed
reference, even though it may actually create the object it returns:
this is possible because an owned reference to the object is stored in
‘sys.modules’.

When you pass an object reference into another function, in general, the
function borrows the reference from you — if it needs to store it, it
will use *note Py_INCREF(): 571. to become an independent owner.  There
are exactly two important exceptions to this rule: *note
PyTuple_SetItem(): 4b83. and *note PyList_SetItem(): 167d.  These
functions take over ownership of the item passed to them — even if they
fail!  (Note that *note PyDict_SetItem(): 4b84. and friends don’t take
over ownership — they are “normal.”)

When a C function is called from Python, it borrows references to its
arguments from the caller.  The caller owns a reference to the object,
so the borrowed reference’s lifetime is guaranteed until the function
returns.  Only when such a borrowed reference must be stored or passed
on, it must be turned into an owned reference by calling *note
Py_INCREF(): 571.

The object reference returned from a C function that is called from
Python must be an owned reference — ownership is transferred from the
function to its caller.


File: python.info,  Node: Thin Ice,  Next: NULL Pointers,  Prev: Ownership Rules,  Up: Reference Counts

6.2.1.13 Thin Ice
.................

There are a few situations where seemingly harmless use of a borrowed
reference can lead to problems.  These all have to do with implicit
invocations of the interpreter, which can cause the owner of a reference
to dispose of it.

The first and most important case to know about is using *note
Py_DECREF(): 572. on an unrelated object while borrowing a reference to
a list item.  For instance:

     void
     bug(PyObject *list)
     {
         PyObject *item = PyList_GetItem(list, 0);

         PyList_SetItem(list, 1, PyLong_FromLong(0L));
         PyObject_Print(item, stdout, 0); /* BUG! */
     }

This function first borrows a reference to ‘list[0]’, then replaces
‘list[1]’ with the value ‘0’, and finally prints the borrowed reference.
Looks harmless, right?  But it’s not!

Let’s follow the control flow into *note PyList_SetItem(): 167d.  The
list owns references to all its items, so when item 1 is replaced, it
has to dispose of the original item 1.  Now let’s suppose the original
item 1 was an instance of a user-defined class, and let’s further
suppose that the class defined a ‘__del__()’ method.  If this class
instance has a reference count of 1, disposing of it will call its
‘__del__()’ method.  Internally, ‘PyList_SetItem()’ calls *note
Py_DECREF(): 572. on the replaced item, which invokes replaced item’s
corresponding *note tp_dealloc: 4b87. function.  During deallocation,
‘tp_dealloc’ calls *note tp_finalize: abb, which is mapped to the
‘__del__()’ method for class instances (see PEP 442(1)).  This entire
sequence happens synchronously within the ‘PyList_SetItem()’ call.

Since it is written in Python, the ‘__del__()’ method can execute
arbitrary Python code.  Could it perhaps do something to invalidate the
reference to ‘item’ in ‘bug()’?  You bet!  Assuming that the list passed
into ‘bug()’ is accessible to the ‘__del__()’ method, it could execute a
statement to the effect of ‘del list[0]’, and assuming this was the last
reference to that object, it would free the memory associated with it,
thereby invalidating ‘item’.

The solution, once you know the source of the problem, is easy:
temporarily increment the reference count.  The correct version of the
function reads:

     void
     no_bug(PyObject *list)
     {
         PyObject *item = PyList_GetItem(list, 0);

         Py_INCREF(item);
         PyList_SetItem(list, 1, PyLong_FromLong(0L));
         PyObject_Print(item, stdout, 0);
         Py_DECREF(item);
     }

This is a true story.  An older version of Python contained variants of
this bug and someone spent a considerable amount of time in a C debugger
to figure out why his ‘__del__()’ methods would fail…

The second case of problems with a borrowed reference is a variant
involving threads.  Normally, multiple threads in the Python interpreter
can’t get in each other’s way, because there is a *note global lock:
148. protecting Python’s entire object space.  However, it is possible
to temporarily release this lock using the macro *note
Py_BEGIN_ALLOW_THREADS: 4b88, and to re-acquire it using *note
Py_END_ALLOW_THREADS: a9d.  This is common around blocking I/O calls, to
let other threads use the processor while waiting for the I/O to
complete.  Obviously, the following function has the same problem as the
previous one:

     void
     bug(PyObject *list)
     {
         PyObject *item = PyList_GetItem(list, 0);
         Py_BEGIN_ALLOW_THREADS
         ...some blocking I/O call...
         Py_END_ALLOW_THREADS
         PyObject_Print(item, stdout, 0); /* BUG! */
     }

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0442/


File: python.info,  Node: NULL Pointers,  Prev: Thin Ice,  Up: Reference Counts

6.2.1.14 NULL Pointers
......................

In general, functions that take object references as arguments do not
expect you to pass them ‘NULL’ pointers, and will dump core (or cause
later core dumps) if you do so.  Functions that return object references
generally return ‘NULL’ only to indicate that an exception occurred.
The reason for not testing for ‘NULL’ arguments is that functions often
pass the objects they receive on to other function — if each function
were to test for ‘NULL’, there would be a lot of redundant tests and the
code would run more slowly.

It is better to test for ‘NULL’ only at the “source:” when a pointer
that may be ‘NULL’ is received, for example, from ‘malloc()’ or from a
function that may raise an exception.

The macros *note Py_INCREF(): 571. and *note Py_DECREF(): 572. do not
check for ‘NULL’ pointers — however, their variants *note Py_XINCREF():
a73. and *note Py_XDECREF(): 792. do.

The macros for checking for a particular object type (‘Pytype_Check()’)
don’t check for ‘NULL’ pointers — again, there is much code that calls
several of these in a row to test an object against various different
expected types, and this would generate redundant tests.  There are no
variants with ‘NULL’ checking.

The C function calling mechanism guarantees that the argument list
passed to C functions (‘args’ in the examples) is never ‘NULL’ — in fact
it guarantees that it is always a tuple (1).

It is a severe error to ever let a ‘NULL’ pointer “escape” to the Python
user.

   ---------- Footnotes ----------

   (1) These guarantees don’t hold when you use the “old” style calling
convention — this is still found in much existing code.


File: python.info,  Node: Writing Extensions in C++,  Next: Providing a C API for an Extension Module,  Prev: Reference Counts,  Up: Extending Python with C or C++

6.2.1.15 Writing Extensions in C++
..................................

It is possible to write extension modules in C++.  Some restrictions
apply.  If the main program (the Python interpreter) is compiled and
linked by the C compiler, global or static objects with constructors
cannot be used.  This is not a problem if the main program is linked by
the C++ compiler.  Functions that will be called by the Python
interpreter (in particular, module initialization functions) have to be
declared using ‘extern "C"’.  It is unnecessary to enclose the Python
header files in ‘extern "C" {...}’ — they use this form already if the
symbol ‘__cplusplus’ is defined (all recent C++ compilers define this
symbol).


File: python.info,  Node: Providing a C API for an Extension Module,  Prev: Writing Extensions in C++,  Up: Extending Python with C or C++

6.2.1.16 Providing a C API for an Extension Module
..................................................

Many extension modules just provide new functions and types to be used
from Python, but sometimes the code in an extension module can be useful
for other extension modules.  For example, an extension module could
implement a type “collection” which works like lists without order.
Just like the standard Python list type has a C API which permits
extension modules to create and manipulate lists, this new collection
type should have a set of C functions for direct manipulation from other
extension modules.

At first sight this seems easy: just write the functions (without
declaring them ‘static’, of course), provide an appropriate header file,
and document the C API. And in fact this would work if all extension
modules were always linked statically with the Python interpreter.  When
modules are used as shared libraries, however, the symbols defined in
one module may not be visible to another module.  The details of
visibility depend on the operating system; some systems use one global
namespace for the Python interpreter and all extension modules (Windows,
for example), whereas others require an explicit list of imported
symbols at module link time (AIX is one example), or offer a choice of
different strategies (most Unices).  And even if symbols are globally
visible, the module whose functions one wishes to call might not have
been loaded yet!

Portability therefore requires not to make any assumptions about symbol
visibility.  This means that all symbols in extension modules should be
declared ‘static’, except for the module’s initialization function, in
order to avoid name clashes with other extension modules (as discussed
in section *note The Module’s Method Table and Initialization Function:
4b6a.).  And it means that symbols that 'should' be accessible from
other extension modules must be exported in a different way.

Python provides a special mechanism to pass C-level information
(pointers) from one extension module to another one: Capsules.  A
Capsule is a Python data type which stores a pointer (void*).  Capsules
can only be created and accessed via their C API, but they can be passed
around like any other Python object.  In particular, they can be
assigned to a name in an extension module’s namespace.  Other extension
modules can then import this module, retrieve the value of this name,
and then retrieve the pointer from the Capsule.

There are many ways in which Capsules can be used to export the C API of
an extension module.  Each function could get its own Capsule, or all C
API pointers could be stored in an array whose address is published in a
Capsule.  And the various tasks of storing and retrieving the pointers
can be distributed in different ways between the module providing the
code and the client modules.

Whichever method you choose, it’s important to name your Capsules
properly.  The function *note PyCapsule_New(): 4b8e. takes a name
parameter (const char*); you’re permitted to pass in a ‘NULL’ name, but
we strongly encourage you to specify a name.  Properly named Capsules
provide a degree of runtime type-safety; there is no feasible way to
tell one unnamed Capsule from another.

In particular, Capsules used to expose C APIs should be given a name
following this convention:

     modulename.attributename

The convenience function *note PyCapsule_Import(): 19b4. makes it easy
to load a C API provided via a Capsule, but only if the Capsule’s name
matches this convention.  This behavior gives C API users a high degree
of certainty that the Capsule they load contains the correct C API.

The following example demonstrates an approach that puts most of the
burden on the writer of the exporting module, which is appropriate for
commonly used library modules.  It stores all C API pointers (just one
in the example!)  in an array of void pointers which becomes the value
of a Capsule.  The header file corresponding to the module provides a
macro that takes care of importing the module and retrieving its C API
pointers; client modules only have to call this macro before accessing
the C API.

The exporting module is a modification of the ‘spam’ module from section
*note A Simple Example: 4b5e.  The function ‘spam.system()’ does not
call the C library function ‘system()’ directly, but a function
‘PySpam_System()’, which would of course do something more complicated
in reality (such as adding “spam” to every command).  This function
‘PySpam_System()’ is also exported to other extension modules.

The function ‘PySpam_System()’ is a plain C function, declared ‘static’
like everything else:

     static int
     PySpam_System(const char *command)
     {
         return system(command);
     }

The function ‘spam_system()’ is modified in a trivial way:

     static PyObject *
     spam_system(PyObject *self, PyObject *args)
     {
         const char *command;
         int sts;

         if (!PyArg_ParseTuple(args, "s", &command))
             return NULL;
         sts = PySpam_System(command);
         return PyLong_FromLong(sts);
     }

In the beginning of the module, right after the line

     #include <Python.h>

two more lines must be added:

     #define SPAM_MODULE
     #include "spammodule.h"

The ‘#define’ is used to tell the header file that it is being included
in the exporting module, not a client module.  Finally, the module’s
*note mod_exec: 988. function must take care of initializing the C API
pointer array:

     static int
     spam_module_exec(PyObject *m)
     {
         static void *PySpam_API[PySpam_API_pointers];
         PyObject *c_api_object;

         /* Initialize the C API pointer array */
         PySpam_API[PySpam_System_NUM] = (void *)PySpam_System;

         /* Create a Capsule containing the API pointer array's address */
         c_api_object = PyCapsule_New((void *)PySpam_API, "spam._C_API", NULL);

         if (PyModule_Add(m, "_C_API", c_api_object) < 0) {
             return -1;
         }

         return 0;
     }

Note that ‘PySpam_API’ is declared ‘static’; otherwise the pointer array
would disappear when ‘PyInit_spam()’ terminates!

The bulk of the work is in the header file ‘spammodule.h’, which looks
like this:

     #ifndef Py_SPAMMODULE_H
     #define Py_SPAMMODULE_H
     #ifdef __cplusplus
     extern "C" {
     #endif

     /* Header file for spammodule */

     /* C API functions */
     #define PySpam_System_NUM 0
     #define PySpam_System_RETURN int
     #define PySpam_System_PROTO (const char *command)

     /* Total number of C API pointers */
     #define PySpam_API_pointers 1


     #ifdef SPAM_MODULE
     /* This section is used when compiling spammodule.c */

     static PySpam_System_RETURN PySpam_System PySpam_System_PROTO;

     #else
     /* This section is used in modules that use spammodule's API */

     static void **PySpam_API;

     #define PySpam_System \
      (*(PySpam_System_RETURN (*)PySpam_System_PROTO) PySpam_API[PySpam_System_NUM])

     /* Return -1 on error, 0 on success.
      * PyCapsule_Import will set an exception if there's an error.
      */
     static int
     import_spam(void)
     {
         PySpam_API = (void **)PyCapsule_Import("spam._C_API", 0);
         return (PySpam_API != NULL) ? 0 : -1;
     }

     #endif

     #ifdef __cplusplus
     }
     #endif

     #endif /* !defined(Py_SPAMMODULE_H) */

All that a client module must do in order to have access to the function
‘PySpam_System()’ is to call the function (or rather macro)
‘import_spam()’ in its *note mod_exec: 988. function:

     static int
     client_module_exec(PyObject *m)
     {
         if (import_spam() < 0) {
             return -1;
         }
         /* additional initialization can happen here */
         return 0;
     }

The main disadvantage of this approach is that the file ‘spammodule.h’
is rather complicated.  However, the basic structure is the same for
each function that is exported, so it has to be learned only once.

Finally it should be mentioned that Capsules offer additional
functionality, which is especially useful for memory allocation and
deallocation of the pointer stored in a Capsule.  The details are
described in the Python/C API Reference Manual in the section *note
Capsules: 2740. and in the implementation of Capsules (files
‘Include/pycapsule.h’ and ‘Objects/pycapsule.c’ in the Python source
code distribution).


File: python.info,  Node: Defining Extension Types Tutorial,  Next: Defining Extension Types Assorted Topics,  Prev: Extending Python with C or C++,  Up: Creating extensions without third party tools

6.2.2 Defining Extension Types: Tutorial
----------------------------------------

Python allows the writer of a C extension module to define new types
that can be manipulated from Python code, much like the built-in *note
str: 44f. and *note list: 614. types.  The code for all extension types
follows a pattern, but there are some details that you need to
understand before you can get started.  This document is a gentle
introduction to the topic.

* Menu:

* The Basics::
* Adding data and methods to the Basic example::
* Providing finer control over data attributes::
* Supporting cyclic garbage collection::
* Subclassing other types::


File: python.info,  Node: The Basics,  Next: Adding data and methods to the Basic example,  Up: Defining Extension Types Tutorial

6.2.2.1 The Basics
..................

The *note CPython: 6f9. runtime sees all Python objects as variables of
type *note PyObject: 33a.*, which serves as a “base type” for all Python
objects.  The *note PyObject: 33a. structure itself only contains the
object’s *note reference count: 4b94. and a pointer to the object’s
“type object”.  This is where the action is; the type object determines
which (C) functions get called by the interpreter when, for instance, an
attribute gets looked up on an object, a method called, or it is
multiplied by another object.  These C functions are called “type
methods”.

So, if you want to define a new extension type, you need to create a new
type object.

This sort of thing can only be explained by example, so here’s a
minimal, but complete, module that defines a new type named ‘Custom’
inside a C extension module ‘custom’:

     Note: What we’re showing here is the traditional way of defining
     'static' extension types.  It should be adequate for most uses.
     The C API also allows defining heap-allocated extension types using
     the *note PyType_FromSpec(): 580. function, which isn’t covered in
     this tutorial.

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     typedef struct {
         PyObject_HEAD
         /* Type-specific fields go here. */
     } CustomObject;

     static PyTypeObject CustomType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "custom.Custom",
         .tp_doc = PyDoc_STR("Custom objects"),
         .tp_basicsize = sizeof(CustomObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT,
         .tp_new = PyType_GenericNew,
     };

     static int
     custom_module_exec(PyObject *m)
     {
         if (PyType_Ready(&CustomType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot custom_module_slots[] = {
         {Py_mod_exec, custom_module_exec},
         // Just use this while using static types
         {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
         {0, NULL}
     };

     static PyModuleDef custom_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "custom",
         .m_doc = "Example module that creates an extension type.",
         .m_size = 0,
         .m_slots = custom_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_custom(void)
     {
         return PyModuleDef_Init(&custom_module);
     }

Now that’s quite a bit to take in at once, but hopefully bits will seem
familiar from the previous chapter.  This file defines three things:

  1. What a ‘Custom’ 'object' contains: this is the ‘CustomObject’
     struct, which is allocated once for each ‘Custom’ instance.

  2. How the ‘Custom’ 'type' behaves: this is the ‘CustomType’ struct,
     which defines a set of flags and function pointers that the
     interpreter inspects when specific operations are requested.

  3. How to define and execute the ‘custom’ module: this is the
     ‘PyInit_custom’ function and the associated ‘custom_module’ struct
     for defining the module, and the ‘custom_module_exec’ function to
     set up a fresh module object.

The first bit is:

     typedef struct {
         PyObject_HEAD
     } CustomObject;

This is what a Custom object will contain.  ‘PyObject_HEAD’ is mandatory
at the start of each object struct and defines a field called ‘ob_base’
of type *note PyObject: 33a, containing a pointer to a type object and a
reference count (these can be accessed using the macros *note Py_TYPE:
783. and *note Py_REFCNT: 8b1. respectively).  The reason for the macro
is to abstract away the layout and to enable additional fields in *note
debug builds: 1f9.

     Note: There is no semicolon above after the *note PyObject_HEAD:
     1326. macro.  Be wary of adding one by accident: some compilers
     will complain.

Of course, objects generally store additional data besides the standard
‘PyObject_HEAD’ boilerplate; for example, here is the definition for
standard Python floats:

     typedef struct {
         PyObject_HEAD
         double ob_fval;
     } PyFloatObject;

The second bit is the definition of the type object.

     static PyTypeObject CustomType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "custom.Custom",
         .tp_doc = PyDoc_STR("Custom objects"),
         .tp_basicsize = sizeof(CustomObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT,
         .tp_new = PyType_GenericNew,
     };

     Note: We recommend using C99-style designated initializers as
     above, to avoid listing all the *note PyTypeObject: aba. fields
     that you don’t care about and also to avoid caring about the
     fields’ declaration order.

The actual definition of *note PyTypeObject: aba. in ‘object.h’ has many
more *note fields: 997. than the definition above.  The remaining fields
will be filled with zeros by the C compiler, and it’s common practice to
not specify them explicitly unless you need them.

We’re going to pick it apart, one field at a time:

     .ob_base = PyVarObject_HEAD_INIT(NULL, 0)

This line is mandatory boilerplate to initialize the ‘ob_base’ field
mentioned above.

     .tp_name = "custom.Custom",

The name of our type.  This will appear in the default textual
representation of our objects and in some error messages, for example:

     >>> "" + custom.Custom()
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: can only concatenate str (not "custom.Custom") to str

Note that the name is a dotted name that includes both the module name
and the name of the type within the module.  The module in this case is
‘custom’ and the type is ‘Custom’, so we set the type name to
‘custom.Custom’.  Using the real dotted import path is important to make
your type compatible with the *note pydoc: b5. and *note pickle: a6.
modules.

     .tp_basicsize = sizeof(CustomObject),
     .tp_itemsize = 0,

This is so that Python knows how much memory to allocate when creating
new ‘Custom’ instances.  *note tp_itemsize: 2121. is only used for
variable-sized objects and should otherwise be zero.

     Note: If you want your type to be subclassable from Python, and
     your type has the same *note tp_basicsize: 991. as its base type,
     you may have problems with multiple inheritance.  A Python subclass
     of your type will have to list your type first in its *note
     __bases__: 14fb, or else it will not be able to call your type’s
     *note __new__(): 583. method without getting an error.  You can
     avoid this problem by ensuring that your type has a larger value
     for ‘tp_basicsize’ than its base type does.  Most of the time, this
     will be true anyway, because either your base type will be *note
     object: a9b, or else you will be adding data members to your base
     type, and therefore increasing its size.

We set the class flags to *note Py_TPFLAGS_DEFAULT: 4b95.

     .tp_flags = Py_TPFLAGS_DEFAULT,

All types should include this constant in their flags.  It enables all
of the members defined until at least Python 3.3.  If you need further
members, you will need to OR the corresponding flags.

We provide a doc string for the type in *note tp_doc: 4b96.

     .tp_doc = PyDoc_STR("Custom objects"),

To enable object creation, we have to provide a *note tp_new: 582.
handler.  This is the equivalent of the Python method *note __new__():
583, but has to be specified explicitly.  In this case, we can just use
the default implementation provided by the API function *note
PyType_GenericNew(): 4b97.

     .tp_new = PyType_GenericNew,

Everything else in the file should be familiar, except for some code in
‘custom_module_exec()’:

     if (PyType_Ready(&CustomType) < 0) {
         return -1;
     }

This initializes the ‘Custom’ type, filling in a number of members to
the appropriate default values, including *note ob_type: 4b98. that we
initially set to ‘NULL’.

     if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
         return -1;
     }

This adds the type to the module dictionary.  This allows us to create
‘Custom’ instances by calling the ‘Custom’ class:

     >>> import custom
     >>> mycustom = custom.Custom()

That’s it!  All that remains is to build it; put the above code in a
file called ‘custom.c’,

     [build-system]
     requires = ["setuptools"]
     build-backend = "setuptools.build_meta"

     [project]
     name = "custom"
     version = "1"

in a file called ‘pyproject.toml’, and

     from setuptools import Extension, setup
     setup(ext_modules=[Extension("custom", ["custom.c"])])

in a file called ‘setup.py’; then typing

     $ python -m pip install .

in a shell should produce a file ‘custom.so’ in a subdirectory and
install it; now fire up Python — you should be able to ‘import custom’
and play around with ‘Custom’ objects.

That wasn’t so hard, was it?

Of course, the current Custom type is pretty uninteresting.  It has no
data and doesn’t do anything.  It can’t even be subclassed.


File: python.info,  Node: Adding data and methods to the Basic example,  Next: Providing finer control over data attributes,  Prev: The Basics,  Up: Defining Extension Types Tutorial

6.2.2.2 Adding data and methods to the Basic example
....................................................

Let’s extend the basic example to add some data and methods.  Let’s also
make the type usable as a base class.  We’ll create a new module,
‘custom2’ that adds these capabilities:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>
     #include <stddef.h> /* for offsetof() */

     typedef struct {
         PyObject_HEAD
         PyObject *first; /* first name */
         PyObject *last;  /* last name */
         int number;
     } CustomObject;

     static void
     Custom_dealloc(CustomObject *self)
     {
         Py_XDECREF(self->first);
         Py_XDECREF(self->last);
         Py_TYPE(self)->tp_free((PyObject *) self);
     }

     static PyObject *
     Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     {
         CustomObject *self;
         self = (CustomObject *) type->tp_alloc(type, 0);
         if (self != NULL) {
             self->first = PyUnicode_FromString("");
             if (self->first == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->last = PyUnicode_FromString("");
             if (self->last == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->number = 0;
         }
         return (PyObject *) self;
     }

     static int
     Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
     {
         static char *kwlist[] = {"first", "last", "number", NULL};
         PyObject *first = NULL, *last = NULL;

         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
                                          &first, &last,
                                          &self->number))
             return -1;

         if (first) {
             Py_XSETREF(self->first, Py_NewRef(first));
         }
         if (last) {
             Py_XSETREF(self->last, Py_NewRef(last));
         }
         return 0;
     }

     static PyMemberDef Custom_members[] = {
         {"first", Py_T_OBJECT_EX, offsetof(CustomObject, first), 0,
          "first name"},
         {"last", Py_T_OBJECT_EX, offsetof(CustomObject, last), 0,
          "last name"},
         {"number", Py_T_INT, offsetof(CustomObject, number), 0,
          "custom number"},
         {NULL}  /* Sentinel */
     };

     static PyObject *
     Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
     {
         if (self->first == NULL) {
             PyErr_SetString(PyExc_AttributeError, "first");
             return NULL;
         }
         if (self->last == NULL) {
             PyErr_SetString(PyExc_AttributeError, "last");
             return NULL;
         }
         return PyUnicode_FromFormat("%S %S", self->first, self->last);
     }

     static PyMethodDef Custom_methods[] = {
         {"name", (PyCFunction) Custom_name, METH_NOARGS,
          "Return the name, combining the first and last name"
         },
         {NULL}  /* Sentinel */
     };

     static PyTypeObject CustomType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "custom2.Custom",
         .tp_doc = PyDoc_STR("Custom objects"),
         .tp_basicsize = sizeof(CustomObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
         .tp_new = Custom_new,
         .tp_init = (initproc) Custom_init,
         .tp_dealloc = (destructor) Custom_dealloc,
         .tp_members = Custom_members,
         .tp_methods = Custom_methods,
     };

     static int
     custom_module_exec(PyObject *m)
     {
         if (PyType_Ready(&CustomType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot custom_module_slots[] = {
         {Py_mod_exec, custom_module_exec},
         {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
         {0, NULL}
     };

     static PyModuleDef custom_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "custom2",
         .m_doc = "Example module that creates an extension type.",
         .m_size = 0,
         .m_slots = custom_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_custom2(void)
     {
         return PyModuleDef_Init(&custom_module);
     }

This version of the module has a number of changes.

The ‘Custom’ type now has three data attributes in its C struct,
'first', 'last', and 'number'.  The 'first' and 'last' variables are
Python strings containing first and last names.  The 'number' attribute
is a C integer.

The object structure is updated accordingly:

     typedef struct {
         PyObject_HEAD
         PyObject *first; /* first name */
         PyObject *last;  /* last name */
         int number;
     } CustomObject;

Because we now have data to manage, we have to be more careful about
object allocation and deallocation.  At a minimum, we need a
deallocation method:

     static void
     Custom_dealloc(CustomObject *self)
     {
         Py_XDECREF(self->first);
         Py_XDECREF(self->last);
         Py_TYPE(self)->tp_free((PyObject *) self);
     }

which is assigned to the *note tp_dealloc: 4b87. member:

     .tp_dealloc = (destructor) Custom_dealloc,

This method first clears the reference counts of the two Python
attributes.  *note Py_XDECREF(): 792. correctly handles the case where
its argument is ‘NULL’ (which might happen here if ‘tp_new’ failed
midway).  It then calls the *note tp_free: 4b9a. member of the object’s
type (computed by ‘Py_TYPE(self)’) to free the object’s memory.  Note
that the object’s type might not be ‘CustomType’, because the object may
be an instance of a subclass.

     Note: The explicit cast to ‘destructor’ above is needed because we
     defined ‘Custom_dealloc’ to take a ‘CustomObject *’ argument, but
     the ‘tp_dealloc’ function pointer expects to receive a ‘PyObject *’
     argument.  Otherwise, the compiler will emit a warning.  This is
     object-oriented polymorphism, in C!

We want to make sure that the first and last names are initialized to
empty strings, so we provide a ‘tp_new’ implementation:

     static PyObject *
     Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     {
         CustomObject *self;
         self = (CustomObject *) type->tp_alloc(type, 0);
         if (self != NULL) {
             self->first = PyUnicode_FromString("");
             if (self->first == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->last = PyUnicode_FromString("");
             if (self->last == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->number = 0;
         }
         return (PyObject *) self;
     }

and install it in the *note tp_new: 582. member:

     .tp_new = Custom_new,

The ‘tp_new’ handler is responsible for creating (as opposed to
initializing) objects of the type.  It is exposed in Python as the *note
__new__(): 583. method.  It is not required to define a ‘tp_new’ member,
and indeed many extension types will simply reuse *note
PyType_GenericNew(): 4b97. as done in the first version of the ‘Custom’
type above.  In this case, we use the ‘tp_new’ handler to initialize the
‘first’ and ‘last’ attributes to non-‘NULL’ default values.

‘tp_new’ is passed the type being instantiated (not necessarily
‘CustomType’, if a subclass is instantiated) and any arguments passed
when the type was called, and is expected to return the instance
created.  ‘tp_new’ handlers always accept positional and keyword
arguments, but they often ignore the arguments, leaving the argument
handling to initializer (a.k.a.  ‘tp_init’ in C or ‘__init__’ in Python)
methods.

     Note: ‘tp_new’ shouldn’t call ‘tp_init’ explicitly, as the
     interpreter will do it itself.

The ‘tp_new’ implementation calls the *note tp_alloc: 4b9b. slot to
allocate memory:

     self = (CustomObject *) type->tp_alloc(type, 0);

Since memory allocation may fail, we must check the *note tp_alloc:
4b9b. result against ‘NULL’ before proceeding.

     Note: We didn’t fill the *note tp_alloc: 4b9b. slot ourselves.
     Rather *note PyType_Ready(): 77f. fills it for us by inheriting it
     from our base class, which is *note object: a9b. by default.  Most
     types use the default allocation strategy.

     Note: If you are creating a co-operative *note tp_new: 582. (one
     that calls a base type’s ‘tp_new’ or *note __new__(): 583.), you
     must 'not' try to determine what method to call using method
     resolution order at runtime.  Always statically determine what type
     you are going to call, and call its ‘tp_new’ directly, or via
     ‘type->tp_base->tp_new’.  If you do not do this, Python subclasses
     of your type that also inherit from other Python-defined classes
     may not work correctly.  (Specifically, you may not be able to
     create instances of such subclasses without getting a *note
     TypeError: 2c3.)

We also define an initialization function which accepts arguments to
provide initial values for our instance:

     static int
     Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
     {
         static char *kwlist[] = {"first", "last", "number", NULL};
         PyObject *first = NULL, *last = NULL, *tmp;

         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OOi", kwlist,
                                          &first, &last,
                                          &self->number))
             return -1;

         if (first) {
             tmp = self->first;
             Py_INCREF(first);
             self->first = first;
             Py_XDECREF(tmp);
         }
         if (last) {
             tmp = self->last;
             Py_INCREF(last);
             self->last = last;
             Py_XDECREF(tmp);
         }
         return 0;
     }

by filling the *note tp_init: 584. slot.

     .tp_init = (initproc) Custom_init,

The *note tp_init: 584. slot is exposed in Python as the *note
__init__(): 6b3. method.  It is used to initialize an object after it’s
created.  Initializers always accept positional and keyword arguments,
and they should return either ‘0’ on success or ‘-1’ on error.

Unlike the ‘tp_new’ handler, there is no guarantee that ‘tp_init’ is
called at all (for example, the *note pickle: a6. module by default
doesn’t call *note __init__(): 6b3. on unpickled instances).  It can
also be called multiple times.  Anyone can call the ‘__init__()’ method
on our objects.  For this reason, we have to be extra careful when
assigning the new attribute values.  We might be tempted, for example to
assign the ‘first’ member like this:

     if (first) {
         Py_XDECREF(self->first);
         Py_INCREF(first);
         self->first = first;
     }

But this would be risky.  Our type doesn’t restrict the type of the
‘first’ member, so it could be any kind of object.  It could have a
destructor that causes code to be executed that tries to access the
‘first’ member; or that destructor could release the *note Global
interpreter Lock: 159. and let arbitrary code run in other threads that
accesses and modifies our object.

To be paranoid and protect ourselves against this possibility, we almost
always reassign members before decrementing their reference counts.
When don’t we have to do this?

   * when we absolutely know that the reference count is greater than 1;

   * when we know that deallocation of the object (1) will neither
     release the *note GIL: 159. nor cause any calls back into our
     type’s code;

   * when decrementing a reference count in a *note tp_dealloc: 4b87.
     handler on a type which doesn’t support cyclic garbage collection
     (2).

We want to expose our instance variables as attributes.  There are a
number of ways to do that.  The simplest way is to define member
definitions:

     static PyMemberDef Custom_members[] = {
         {"first", Py_T_OBJECT_EX, offsetof(CustomObject, first), 0,
          "first name"},
         {"last", Py_T_OBJECT_EX, offsetof(CustomObject, last), 0,
          "last name"},
         {"number", Py_T_INT, offsetof(CustomObject, number), 0,
          "custom number"},
         {NULL}  /* Sentinel */
     };

and put the definitions in the *note tp_members: 4b9c. slot:

     .tp_members = Custom_members,

Each member definition has a member name, type, offset, access flags and
documentation string.  See the *note Generic Attribute Management: 4b9d.
section below for details.

A disadvantage of this approach is that it doesn’t provide a way to
restrict the types of objects that can be assigned to the Python
attributes.  We expect the first and last names to be strings, but any
Python objects can be assigned.  Further, the attributes can be deleted,
setting the C pointers to ‘NULL’.  Even though we can make sure the
members are initialized to non-‘NULL’ values, the members can be set to
‘NULL’ if the attributes are deleted.

We define a single method, ‘Custom.name()’, that outputs the objects
name as the concatenation of the first and last names.

     static PyObject *
     Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
     {
         if (self->first == NULL) {
             PyErr_SetString(PyExc_AttributeError, "first");
             return NULL;
         }
         if (self->last == NULL) {
             PyErr_SetString(PyExc_AttributeError, "last");
             return NULL;
         }
         return PyUnicode_FromFormat("%S %S", self->first, self->last);
     }

The method is implemented as a C function that takes a ‘Custom’ (or
‘Custom’ subclass) instance as the first argument.  Methods always take
an instance as the first argument.  Methods often take positional and
keyword arguments as well, but in this case we don’t take any and don’t
need to accept a positional argument tuple or keyword argument
dictionary.  This method is equivalent to the Python method:

     def name(self):
         return "%s %s" % (self.first, self.last)

Note that we have to check for the possibility that our ‘first’ and
‘last’ members are ‘NULL’.  This is because they can be deleted, in
which case they are set to ‘NULL’.  It would be better to prevent
deletion of these attributes and to restrict the attribute values to be
strings.  We’ll see how to do that in the next section.

Now that we’ve defined the method, we need to create an array of method
definitions:

     static PyMethodDef Custom_methods[] = {
         {"name", (PyCFunction) Custom_name, METH_NOARGS,
          "Return the name, combining the first and last name"
         },
         {NULL}  /* Sentinel */
     };

(note that we used the *note METH_NOARGS: 1523. flag to indicate that
the method is expecting no arguments other than 'self')

and assign it to the *note tp_methods: 4b9e. slot:

     .tp_methods = Custom_methods,

Finally, we’ll make our type usable as a base class for subclassing.
We’ve written our methods carefully so far so that they don’t make any
assumptions about the type of the object being created or used, so all
we need to do is to add the *note Py_TPFLAGS_BASETYPE: 4b9f. to our
class flag definition:

     .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,

We rename ‘PyInit_custom()’ to ‘PyInit_custom2()’, update the module
name in the *note PyModuleDef: 987. struct, and update the full class
name in the *note PyTypeObject: aba. struct.

Finally, we update our ‘setup.py’ file to include the new module,

     from setuptools import Extension, setup
     setup(ext_modules=[
         Extension("custom", ["custom.c"]),
         Extension("custom2", ["custom2.c"]),
     ])

and then we re-install so that we can ‘import custom2’:

     $ python -m pip install .

   ---------- Footnotes ----------

   (1) This is true when we know that the object is a basic type, like a
string or a float.

   (2) We relied on this in the *note tp_dealloc: 4b87. handler in this
example, because our type doesn’t support garbage collection.


File: python.info,  Node: Providing finer control over data attributes,  Next: Supporting cyclic garbage collection,  Prev: Adding data and methods to the Basic example,  Up: Defining Extension Types Tutorial

6.2.2.3 Providing finer control over data attributes
....................................................

In this section, we’ll provide finer control over how the ‘first’ and
‘last’ attributes are set in the ‘Custom’ example.  In the previous
version of our module, the instance variables ‘first’ and ‘last’ could
be set to non-string values or even deleted.  We want to make sure that
these attributes always contain strings.

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>
     #include <stddef.h> /* for offsetof() */

     typedef struct {
         PyObject_HEAD
         PyObject *first; /* first name */
         PyObject *last;  /* last name */
         int number;
     } CustomObject;

     static void
     Custom_dealloc(CustomObject *self)
     {
         Py_XDECREF(self->first);
         Py_XDECREF(self->last);
         Py_TYPE(self)->tp_free((PyObject *) self);
     }

     static PyObject *
     Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     {
         CustomObject *self;
         self = (CustomObject *) type->tp_alloc(type, 0);
         if (self != NULL) {
             self->first = PyUnicode_FromString("");
             if (self->first == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->last = PyUnicode_FromString("");
             if (self->last == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->number = 0;
         }
         return (PyObject *) self;
     }

     static int
     Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
     {
         static char *kwlist[] = {"first", "last", "number", NULL};
         PyObject *first = NULL, *last = NULL;

         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                          &first, &last,
                                          &self->number))
             return -1;

         if (first) {
             Py_SETREF(self->first, Py_NewRef(first));
         }
         if (last) {
             Py_SETREF(self->last, Py_NewRef(last));
         }
         return 0;
     }

     static PyMemberDef Custom_members[] = {
         {"number", Py_T_INT, offsetof(CustomObject, number), 0,
          "custom number"},
         {NULL}  /* Sentinel */
     };

     static PyObject *
     Custom_getfirst(CustomObject *self, void *closure)
     {
         return Py_NewRef(self->first);
     }

     static int
     Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
     {
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
             return -1;
         }
         if (!PyUnicode_Check(value)) {
             PyErr_SetString(PyExc_TypeError,
                             "The first attribute value must be a string");
             return -1;
         }
         Py_SETREF(self->first, Py_NewRef(value));
         return 0;
     }

     static PyObject *
     Custom_getlast(CustomObject *self, void *closure)
     {
         return Py_NewRef(self->last);
     }

     static int
     Custom_setlast(CustomObject *self, PyObject *value, void *closure)
     {
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
             return -1;
         }
         if (!PyUnicode_Check(value)) {
             PyErr_SetString(PyExc_TypeError,
                             "The last attribute value must be a string");
             return -1;
         }
         Py_SETREF(self->last, Py_NewRef(value));
         return 0;
     }

     static PyGetSetDef Custom_getsetters[] = {
         {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
          "first name", NULL},
         {"last", (getter) Custom_getlast, (setter) Custom_setlast,
          "last name", NULL},
         {NULL}  /* Sentinel */
     };

     static PyObject *
     Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
     {
         return PyUnicode_FromFormat("%S %S", self->first, self->last);
     }

     static PyMethodDef Custom_methods[] = {
         {"name", (PyCFunction) Custom_name, METH_NOARGS,
          "Return the name, combining the first and last name"
         },
         {NULL}  /* Sentinel */
     };

     static PyTypeObject CustomType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "custom3.Custom",
         .tp_doc = PyDoc_STR("Custom objects"),
         .tp_basicsize = sizeof(CustomObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
         .tp_new = Custom_new,
         .tp_init = (initproc) Custom_init,
         .tp_dealloc = (destructor) Custom_dealloc,
         .tp_members = Custom_members,
         .tp_methods = Custom_methods,
         .tp_getset = Custom_getsetters,
     };

     static int
     custom_module_exec(PyObject *m)
     {
         if (PyType_Ready(&CustomType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot custom_module_slots[] = {
         {Py_mod_exec, custom_module_exec},
         {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
         {0, NULL}
     };

     static PyModuleDef custom_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "custom3",
         .m_doc = "Example module that creates an extension type.",
         .m_size = 0,
         .m_slots = custom_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_custom3(void)
     {
         return PyModuleDef_Init(&custom_module);
     }

To provide greater control, over the ‘first’ and ‘last’ attributes,
we’ll use custom getter and setter functions.  Here are the functions
for getting and setting the ‘first’ attribute:

     static PyObject *
     Custom_getfirst(CustomObject *self, void *closure)
     {
         Py_INCREF(self->first);
         return self->first;
     }

     static int
     Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
     {
         PyObject *tmp;
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
             return -1;
         }
         if (!PyUnicode_Check(value)) {
             PyErr_SetString(PyExc_TypeError,
                             "The first attribute value must be a string");
             return -1;
         }
         tmp = self->first;
         Py_INCREF(value);
         self->first = value;
         Py_DECREF(tmp);
         return 0;
     }

The getter function is passed a ‘Custom’ object and a “closure”, which
is a void pointer.  In this case, the closure is ignored.  (The closure
supports an advanced usage in which definition data is passed to the
getter and setter.  This could, for example, be used to allow a single
set of getter and setter functions that decide the attribute to get or
set based on data in the closure.)

The setter function is passed the ‘Custom’ object, the new value, and
the closure.  The new value may be ‘NULL’, in which case the attribute
is being deleted.  In our setter, we raise an error if the attribute is
deleted or if its new value is not a string.

We create an array of *note PyGetSetDef: bd7. structures:

     static PyGetSetDef Custom_getsetters[] = {
         {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
          "first name", NULL},
         {"last", (getter) Custom_getlast, (setter) Custom_setlast,
          "last name", NULL},
         {NULL}  /* Sentinel */
     };

and register it in the *note tp_getset: 4ba1. slot:

     .tp_getset = Custom_getsetters,

The last item in a *note PyGetSetDef: bd7. structure is the “closure”
mentioned above.  In this case, we aren’t using a closure, so we just
pass ‘NULL’.

We also remove the member definitions for these attributes:

     static PyMemberDef Custom_members[] = {
         {"number", Py_T_INT, offsetof(CustomObject, number), 0,
          "custom number"},
         {NULL}  /* Sentinel */
     };

We also need to update the *note tp_init: 584. handler to only allow
strings (1) to be passed:

     static int
     Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
     {
         static char *kwlist[] = {"first", "last", "number", NULL};
         PyObject *first = NULL, *last = NULL, *tmp;

         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                          &first, &last,
                                          &self->number))
             return -1;

         if (first) {
             tmp = self->first;
             Py_INCREF(first);
             self->first = first;
             Py_DECREF(tmp);
         }
         if (last) {
             tmp = self->last;
             Py_INCREF(last);
             self->last = last;
             Py_DECREF(tmp);
         }
         return 0;
     }

With these changes, we can assure that the ‘first’ and ‘last’ members
are never ‘NULL’ so we can remove checks for ‘NULL’ values in almost all
cases.  This means that most of the *note Py_XDECREF(): 792. calls can
be converted to *note Py_DECREF(): 572. calls.  The only place we can’t
change these calls is in the ‘tp_dealloc’ implementation, where there is
the possibility that the initialization of these members failed in
‘tp_new’.

We also rename the module initialization function and module name in the
initialization function, as we did before, and we add an extra
definition to the ‘setup.py’ file.

   ---------- Footnotes ----------

   (1) We now know that the first and last members are strings, so
perhaps we could be less careful about decrementing their reference
counts, however, we accept instances of string subclasses.  Even though
deallocating normal strings won’t call back into our objects, we can’t
guarantee that deallocating an instance of a string subclass won’t call
back into our objects.


File: python.info,  Node: Supporting cyclic garbage collection,  Next: Subclassing other types,  Prev: Providing finer control over data attributes,  Up: Defining Extension Types Tutorial

6.2.2.4 Supporting cyclic garbage collection
............................................

Python has a *note cyclic garbage collector (GC): 1a83. that can
identify unneeded objects even when their reference counts are not zero.
This can happen when objects are involved in cycles.  For example,
consider:

     >>> l = []
     >>> l.append(l)
     >>> del l

In this example, we create a list that contains itself.  When we delete
it, it still has a reference from itself.  Its reference count doesn’t
drop to zero.  Fortunately, Python’s cyclic garbage collector will
eventually figure out that the list is garbage and free it.

In the second version of the ‘Custom’ example, we allowed any kind of
object to be stored in the ‘first’ or ‘last’ attributes (1).  Besides,
in the second and third versions, we allowed subclassing ‘Custom’, and
subclasses may add arbitrary attributes.  For any of those two reasons,
‘Custom’ objects can participate in cycles:

     >>> import custom3
     >>> class Derived(custom3.Custom): pass
     ...
     >>> n = Derived()
     >>> n.some_attribute = n

To allow a ‘Custom’ instance participating in a reference cycle to be
properly detected and collected by the cyclic GC, our ‘Custom’ type
needs to fill two additional slots and to enable a flag that enables
these slots:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>
     #include <stddef.h> /* for offsetof() */

     typedef struct {
         PyObject_HEAD
         PyObject *first; /* first name */
         PyObject *last;  /* last name */
         int number;
     } CustomObject;

     static int
     Custom_traverse(CustomObject *self, visitproc visit, void *arg)
     {
         Py_VISIT(self->first);
         Py_VISIT(self->last);
         return 0;
     }

     static int
     Custom_clear(CustomObject *self)
     {
         Py_CLEAR(self->first);
         Py_CLEAR(self->last);
         return 0;
     }

     static void
     Custom_dealloc(CustomObject *self)
     {
         PyObject_GC_UnTrack(self);
         Custom_clear(self);
         Py_TYPE(self)->tp_free((PyObject *) self);
     }

     static PyObject *
     Custom_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     {
         CustomObject *self;
         self = (CustomObject *) type->tp_alloc(type, 0);
         if (self != NULL) {
             self->first = PyUnicode_FromString("");
             if (self->first == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->last = PyUnicode_FromString("");
             if (self->last == NULL) {
                 Py_DECREF(self);
                 return NULL;
             }
             self->number = 0;
         }
         return (PyObject *) self;
     }

     static int
     Custom_init(CustomObject *self, PyObject *args, PyObject *kwds)
     {
         static char *kwlist[] = {"first", "last", "number", NULL};
         PyObject *first = NULL, *last = NULL;

         if (!PyArg_ParseTupleAndKeywords(args, kwds, "|UUi", kwlist,
                                          &first, &last,
                                          &self->number))
             return -1;

         if (first) {
             Py_SETREF(self->first, Py_NewRef(first));
         }
         if (last) {
             Py_SETREF(self->last, Py_NewRef(last));
         }
         return 0;
     }

     static PyMemberDef Custom_members[] = {
         {"number", Py_T_INT, offsetof(CustomObject, number), 0,
          "custom number"},
         {NULL}  /* Sentinel */
     };

     static PyObject *
     Custom_getfirst(CustomObject *self, void *closure)
     {
         return Py_NewRef(self->first);
     }

     static int
     Custom_setfirst(CustomObject *self, PyObject *value, void *closure)
     {
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError, "Cannot delete the first attribute");
             return -1;
         }
         if (!PyUnicode_Check(value)) {
             PyErr_SetString(PyExc_TypeError,
                             "The first attribute value must be a string");
             return -1;
         }
         Py_XSETREF(self->first, Py_NewRef(value));
         return 0;
     }

     static PyObject *
     Custom_getlast(CustomObject *self, void *closure)
     {
         return Py_NewRef(self->last);
     }

     static int
     Custom_setlast(CustomObject *self, PyObject *value, void *closure)
     {
         if (value == NULL) {
             PyErr_SetString(PyExc_TypeError, "Cannot delete the last attribute");
             return -1;
         }
         if (!PyUnicode_Check(value)) {
             PyErr_SetString(PyExc_TypeError,
                             "The last attribute value must be a string");
             return -1;
         }
         Py_XSETREF(self->last, Py_NewRef(value));
         return 0;
     }

     static PyGetSetDef Custom_getsetters[] = {
         {"first", (getter) Custom_getfirst, (setter) Custom_setfirst,
          "first name", NULL},
         {"last", (getter) Custom_getlast, (setter) Custom_setlast,
          "last name", NULL},
         {NULL}  /* Sentinel */
     };

     static PyObject *
     Custom_name(CustomObject *self, PyObject *Py_UNUSED(ignored))
     {
         return PyUnicode_FromFormat("%S %S", self->first, self->last);
     }

     static PyMethodDef Custom_methods[] = {
         {"name", (PyCFunction) Custom_name, METH_NOARGS,
          "Return the name, combining the first and last name"
         },
         {NULL}  /* Sentinel */
     };

     static PyTypeObject CustomType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "custom4.Custom",
         .tp_doc = PyDoc_STR("Custom objects"),
         .tp_basicsize = sizeof(CustomObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
         .tp_new = Custom_new,
         .tp_init = (initproc) Custom_init,
         .tp_dealloc = (destructor) Custom_dealloc,
         .tp_traverse = (traverseproc) Custom_traverse,
         .tp_clear = (inquiry) Custom_clear,
         .tp_members = Custom_members,
         .tp_methods = Custom_methods,
         .tp_getset = Custom_getsetters,
     };

     static int
     custom_module_exec(PyObject *m)
     {
         if (PyType_Ready(&CustomType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "Custom", (PyObject *) &CustomType) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot custom_module_slots[] = {
         {Py_mod_exec, custom_module_exec},
         {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
         {0, NULL}
     };

     static PyModuleDef custom_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "custom4",
         .m_doc = "Example module that creates an extension type.",
         .m_size = 0,
         .m_slots = custom_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_custom4(void)
     {
         return PyModuleDef_Init(&custom_module);
     }

First, the traversal method lets the cyclic GC know about subobjects
that could participate in cycles:

     static int
     Custom_traverse(CustomObject *self, visitproc visit, void *arg)
     {
         int vret;
         if (self->first) {
             vret = visit(self->first, arg);
             if (vret != 0)
                 return vret;
         }
         if (self->last) {
             vret = visit(self->last, arg);
             if (vret != 0)
                 return vret;
         }
         return 0;
     }

For each subobject that can participate in cycles, we need to call the
‘visit()’ function, which is passed to the traversal method.  The
‘visit()’ function takes as arguments the subobject and the extra
argument 'arg' passed to the traversal method.  It returns an integer
value that must be returned if it is non-zero.

Python provides a *note Py_VISIT(): 4ba3. macro that automates calling
visit functions.  With ‘Py_VISIT()’, we can minimize the amount of
boilerplate in ‘Custom_traverse’:

     static int
     Custom_traverse(CustomObject *self, visitproc visit, void *arg)
     {
         Py_VISIT(self->first);
         Py_VISIT(self->last);
         return 0;
     }

     Note: The *note tp_traverse: 781. implementation must name its
     arguments exactly 'visit' and 'arg' in order to use *note
     Py_VISIT(): 4ba3.

Second, we need to provide a method for clearing any subobjects that can
participate in cycles:

     static int
     Custom_clear(CustomObject *self)
     {
         Py_CLEAR(self->first);
         Py_CLEAR(self->last);
         return 0;
     }

Notice the use of the *note Py_CLEAR(): 57b. macro.  It is the
recommended and safe way to clear data attributes of arbitrary types
while decrementing their reference counts.  If you were to call *note
Py_XDECREF(): 792. instead on the attribute before setting it to ‘NULL’,
there is a possibility that the attribute’s destructor would call back
into code that reads the attribute again ('especially' if there is a
reference cycle).

     Note: You could emulate *note Py_CLEAR(): 57b. by writing:

          PyObject *tmp;
          tmp = self->first;
          self->first = NULL;
          Py_XDECREF(tmp);

     Nevertheless, it is much easier and less error-prone to always use
     *note Py_CLEAR(): 57b. when deleting an attribute.  Don’t try to
     micro-optimize at the expense of robustness!

The deallocator ‘Custom_dealloc’ may call arbitrary code when clearing
attributes.  It means the circular GC can be triggered inside the
function.  Since the GC assumes reference count is not zero, we need to
untrack the object from the GC by calling *note PyObject_GC_UnTrack():
1555. before clearing members.  Here is our reimplemented deallocator
using ‘PyObject_GC_UnTrack()’ and ‘Custom_clear’:

     static void
     Custom_dealloc(CustomObject *self)
     {
         PyObject_GC_UnTrack(self);
         Custom_clear(self);
         Py_TYPE(self)->tp_free((PyObject *) self);
     }

Finally, we add the *note Py_TPFLAGS_HAVE_GC: 780. flag to the class
flags:

     .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,

That’s pretty much it.  If we had written custom *note tp_alloc: 4b9b.
or *note tp_free: 4b9a. handlers, we’d need to modify them for cyclic
garbage collection.  Most extensions will use the versions automatically
provided.

   ---------- Footnotes ----------

   (1) Also, even with our attributes restricted to strings instances,
the user could pass arbitrary *note str: 44f. subclasses and therefore
still create reference cycles.


File: python.info,  Node: Subclassing other types,  Prev: Supporting cyclic garbage collection,  Up: Defining Extension Types Tutorial

6.2.2.5 Subclassing other types
...............................

It is possible to create new extension types that are derived from
existing types.  It is easiest to inherit from the built in types, since
an extension can easily use the *note PyTypeObject: aba. it needs.  It
can be difficult to share these ‘PyTypeObject’ structures between
extension modules.

In this example we will create a ‘SubList’ type that inherits from the
built-in *note list: 614. type.  The new type will be completely
compatible with regular lists, but will have an additional ‘increment()’
method that increases an internal counter:

     >>> import sublist
     >>> s = sublist.SubList(range(3))
     >>> s.extend(s)
     >>> print(len(s))
     6
     >>> print(s.increment())
     1
     >>> print(s.increment())
     2

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     typedef struct {
         PyListObject list;
         int state;
     } SubListObject;

     static PyObject *
     SubList_increment(SubListObject *self, PyObject *unused)
     {
         self->state++;
         return PyLong_FromLong(self->state);
     }

     static PyMethodDef SubList_methods[] = {
         {"increment", (PyCFunction) SubList_increment, METH_NOARGS,
          PyDoc_STR("increment state counter")},
         {NULL},
     };

     static int
     SubList_init(SubListObject *self, PyObject *args, PyObject *kwds)
     {
         if (PyList_Type.tp_init((PyObject *) self, args, kwds) < 0)
             return -1;
         self->state = 0;
         return 0;
     }

     static PyTypeObject SubListType = {
         .ob_base = PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "sublist.SubList",
         .tp_doc = PyDoc_STR("SubList objects"),
         .tp_basicsize = sizeof(SubListObject),
         .tp_itemsize = 0,
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
         .tp_init = (initproc) SubList_init,
         .tp_methods = SubList_methods,
     };

     static int
     sublist_module_exec(PyObject *m)
     {
         SubListType.tp_base = &PyList_Type;
         if (PyType_Ready(&SubListType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "SubList", (PyObject *) &SubListType) < 0) {
             return -1;
         }

         return 0;
     }

     static PyModuleDef_Slot sublist_module_slots[] = {
         {Py_mod_exec, sublist_module_exec},
         {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
         {0, NULL}
     };

     static PyModuleDef sublist_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "sublist",
         .m_doc = "Example module that creates an extension type.",
         .m_size = 0,
         .m_slots = sublist_module_slots,
     };

     PyMODINIT_FUNC
     PyInit_sublist(void)
     {
         return PyModuleDef_Init(&sublist_module);
     }

As you can see, the source code closely resembles the ‘Custom’ examples
in previous sections.  We will break down the main differences between
them.

     typedef struct {
         PyListObject list;
         int state;
     } SubListObject;

The primary difference for derived type objects is that the base type’s
object structure must be the first value.  The base type will already
include the *note PyObject_HEAD(): 1326. at the beginning of its
structure.

When a Python object is a ‘SubList’ instance, its ‘PyObject *’ pointer
can be safely cast to both ‘PyListObject *’ and ‘SubListObject *’:

     static int
     SubList_init(SubListObject *self, PyObject *args, PyObject *kwds)
     {
         if (PyList_Type.tp_init((PyObject *) self, args, kwds) < 0)
             return -1;
         self->state = 0;
         return 0;
     }

We see above how to call through to the *note __init__(): 6b3. method of
the base type.

This pattern is important when writing a type with custom *note tp_new:
582. and *note tp_dealloc: 4b87. members.  The ‘tp_new’ handler should
not actually create the memory for the object with its *note tp_alloc:
4b9b, but let the base class handle it by calling its own ‘tp_new’.

The *note PyTypeObject: aba. struct supports a *note tp_base: 20d7.
specifying the type’s concrete base class.  Due to cross-platform
compiler issues, you can’t fill that field directly with a reference to
*note PyList_Type: 4ba5.; it should be done in the *note Py_mod_exec:
988. function:

     static int
     sublist_module_exec(PyObject *m)
     {
         SubListType.tp_base = &PyList_Type;
         if (PyType_Ready(&SubListType) < 0) {
             return -1;
         }

         if (PyModule_AddObjectRef(m, "SubList", (PyObject *) &SubListType) < 0) {
             return -1;
         }

         return 0;
     }

Before calling *note PyType_Ready(): 77f, the type structure must have
the *note tp_base: 20d7. slot filled in.  When we are deriving an
existing type, it is not necessary to fill out the *note tp_alloc: 4b9b.
slot with *note PyType_GenericNew(): 4b97. – the allocation function
from the base type will be inherited.

After that, calling *note PyType_Ready(): 77f. and adding the type
object to the module is the same as with the basic ‘Custom’ examples.


File: python.info,  Node: Defining Extension Types Assorted Topics,  Next: Building C and C++ Extensions,  Prev: Defining Extension Types Tutorial,  Up: Creating extensions without third party tools

6.2.3 Defining Extension Types: Assorted Topics
-----------------------------------------------

This section aims to give a quick fly-by on the various type methods you
can implement and what they do.

Here is the definition of *note PyTypeObject: aba, with some fields only
used in *note debug builds: 1f9. omitted:

     typedef struct _typeobject {
         PyObject_VAR_HEAD
         const char *tp_name; /* For printing, in format "<module>.<name>" */
         Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

         /* Methods to implement standard operations */

         destructor tp_dealloc;
         Py_ssize_t tp_vectorcall_offset;
         getattrfunc tp_getattr;
         setattrfunc tp_setattr;
         PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
                                         or tp_reserved (Python 3) */
         reprfunc tp_repr;

         /* Method suites for standard classes */

         PyNumberMethods *tp_as_number;
         PySequenceMethods *tp_as_sequence;
         PyMappingMethods *tp_as_mapping;

         /* More standard operations (here for binary compatibility) */

         hashfunc tp_hash;
         ternaryfunc tp_call;
         reprfunc tp_str;
         getattrofunc tp_getattro;
         setattrofunc tp_setattro;

         /* Functions to access object as input/output buffer */
         PyBufferProcs *tp_as_buffer;

         /* Flags to define presence of optional/expanded features */
         unsigned long tp_flags;

         const char *tp_doc; /* Documentation string */

         /* Assigned meaning in release 2.0 */
         /* call function for all accessible objects */
         traverseproc tp_traverse;

         /* delete references to contained objects */
         inquiry tp_clear;

         /* Assigned meaning in release 2.1 */
         /* rich comparisons */
         richcmpfunc tp_richcompare;

         /* weak reference enabler */
         Py_ssize_t tp_weaklistoffset;

         /* Iterators */
         getiterfunc tp_iter;
         iternextfunc tp_iternext;

         /* Attribute descriptor and subclassing stuff */
         struct PyMethodDef *tp_methods;
         struct PyMemberDef *tp_members;
         struct PyGetSetDef *tp_getset;
         // Strong reference on a heap type, borrowed reference on a static type
         struct _typeobject *tp_base;
         PyObject *tp_dict;
         descrgetfunc tp_descr_get;
         descrsetfunc tp_descr_set;
         Py_ssize_t tp_dictoffset;
         initproc tp_init;
         allocfunc tp_alloc;
         newfunc tp_new;
         freefunc tp_free; /* Low-level free-memory routine */
         inquiry tp_is_gc; /* For PyObject_IS_GC */
         PyObject *tp_bases;
         PyObject *tp_mro; /* method resolution order */
         PyObject *tp_cache;
         PyObject *tp_subclasses;
         PyObject *tp_weaklist;
         destructor tp_del;

         /* Type attribute cache version tag. Added in version 2.6 */
         unsigned int tp_version_tag;

         destructor tp_finalize;
         vectorcallfunc tp_vectorcall;

         /* bitset of which type-watchers care about this type */
         unsigned char tp_watched;
     } PyTypeObject;

Now that’s a 'lot' of methods.  Don’t worry too much though – if you
have a type you want to define, the chances are very good that you will
only implement a handful of these.

As you probably expect by now, we’re going to go over this and give more
information about the various handlers.  We won’t go in the order they
are defined in the structure, because there is a lot of historical
baggage that impacts the ordering of the fields.  It’s often easiest to
find an example that includes the fields you need and then change the
values to suit your new type.

     const char *tp_name; /* For printing */

The name of the type – as mentioned in the previous chapter, this will
appear in various places, almost entirely for diagnostic purposes.  Try
to choose something that will be helpful in such a situation!

     Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

These fields tell the runtime how much memory to allocate when new
objects of this type are created.  Python has some built-in support for
variable length structures (think: strings, tuples) which is where the
*note tp_itemsize: 2121. field comes in.  This will be dealt with later.

     const char *tp_doc;

Here you can put a string (or its address) that you want returned when
the Python script references ‘obj.__doc__’ to retrieve the doc string.

Now we come to the basic type methods – the ones most extension types
will implement.

* Menu:

* Finalization and De-allocation::
* Object Presentation::
* Attribute Management::
* Object Comparison::
* Abstract Protocol Support::
* Weak Reference Support::
* More Suggestions::


File: python.info,  Node: Finalization and De-allocation,  Next: Object Presentation,  Up: Defining Extension Types Assorted Topics

6.2.3.1 Finalization and De-allocation
......................................

     destructor tp_dealloc;

This function is called when the reference count of the instance of your
type is reduced to zero and the Python interpreter wants to reclaim it.
If your type has memory to free or other clean-up to perform, you can
put it here.  The object itself needs to be freed here as well.  Here is
an example of this function:

     static void
     newdatatype_dealloc(newdatatypeobject *obj)
     {
         free(obj->obj_UnderlyingDatatypePtr);
         Py_TYPE(obj)->tp_free((PyObject *)obj);
     }

If your type supports garbage collection, the destructor should call
*note PyObject_GC_UnTrack(): 1555. before clearing any member fields:

     static void
     newdatatype_dealloc(newdatatypeobject *obj)
     {
         PyObject_GC_UnTrack(obj);
         Py_CLEAR(obj->other_obj);
         ...
         Py_TYPE(obj)->tp_free((PyObject *)obj);
     }

One important requirement of the deallocator function is that it leaves
any pending exceptions alone.  This is important since deallocators are
frequently called as the interpreter unwinds the Python stack; when the
stack is unwound due to an exception (rather than normal returns),
nothing is done to protect the deallocators from seeing that an
exception has already been set.  Any actions which a deallocator
performs which may cause additional Python code to be executed may
detect that an exception has been set.  This can lead to misleading
errors from the interpreter.  The proper way to protect against this is
to save a pending exception before performing the unsafe action, and
restoring it when done.  This can be done using the *note PyErr_Fetch():
3f6. and *note PyErr_Restore(): 3f9. functions:

     static void
     my_dealloc(PyObject *obj)
     {
         MyObject *self = (MyObject *) obj;
         PyObject *cbresult;

         if (self->my_callback != NULL) {
             PyObject *err_type, *err_value, *err_traceback;

             /* This saves the current exception state */
             PyErr_Fetch(&err_type, &err_value, &err_traceback);

             cbresult = PyObject_CallNoArgs(self->my_callback);
             if (cbresult == NULL)
                 PyErr_WriteUnraisable(self->my_callback);
             else
                 Py_DECREF(cbresult);

             /* This restores the saved exception state */
             PyErr_Restore(err_type, err_value, err_traceback);

             Py_DECREF(self->my_callback);
         }
         Py_TYPE(obj)->tp_free((PyObject*)self);
     }

     Note: There are limitations to what you can safely do in a
     deallocator function.  First, if your type supports garbage
     collection (using *note tp_traverse: 781. and/or *note tp_clear:
     4bac.), some of the object’s members can have been cleared or
     finalized by the time *note tp_dealloc: 4b87. is called.  Second,
     in ‘tp_dealloc’, your object is in an unstable state: its reference
     count is equal to zero.  Any call to a non-trivial object or API
     (as in the example above) might end up calling ‘tp_dealloc’ again,
     causing a double free and a crash.

     Starting with Python 3.4, it is recommended not to put any complex
     finalization code in *note tp_dealloc: 4b87, and instead use the
     new *note tp_finalize: abb. type method.

     See also
     ........

     PEP 442(1) explains the new finalization scheme.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0442/


File: python.info,  Node: Object Presentation,  Next: Attribute Management,  Prev: Finalization and De-allocation,  Up: Defining Extension Types Assorted Topics

6.2.3.2 Object Presentation
...........................

In Python, there are two ways to generate a textual representation of an
object: the *note repr(): 803. function, and the *note str(): 44f.
function.  (The *note print(): fae. function just calls ‘str()’.)  These
handlers are both optional.

     reprfunc tp_repr;
     reprfunc tp_str;

The *note tp_repr: 4bae. handler should return a string object
containing a representation of the instance for which it is called.
Here is a simple example:

     static PyObject *
     newdatatype_repr(newdatatypeobject *obj)
     {
         return PyUnicode_FromFormat("Repr-ified_newdatatype{{size:%d}}",
                                     obj->obj_UnderlyingDatatypePtr->size);
     }

If no *note tp_repr: 4bae. handler is specified, the interpreter will
supply a representation that uses the type’s *note tp_name: 1a56. and a
uniquely identifying value for the object.

The *note tp_str: 4baf. handler is to *note str(): 44f. what the *note
tp_repr: 4bae. handler described above is to *note repr(): 803.; that
is, it is called when Python code calls ‘str()’ on an instance of your
object.  Its implementation is very similar to the ‘tp_repr’ function,
but the resulting string is intended for human consumption.  If ‘tp_str’
is not specified, the ‘tp_repr’ handler is used instead.

Here is a simple example:

     static PyObject *
     newdatatype_str(newdatatypeobject *obj)
     {
         return PyUnicode_FromFormat("Stringified_newdatatype{{size:%d}}",
                                     obj->obj_UnderlyingDatatypePtr->size);
     }


File: python.info,  Node: Attribute Management,  Next: Object Comparison,  Prev: Object Presentation,  Up: Defining Extension Types Assorted Topics

6.2.3.3 Attribute Management
............................

For every object which can support attributes, the corresponding type
must provide the functions that control how the attributes are resolved.
There needs to be a function which can retrieve attributes (if any are
defined), and another to set attributes (if setting attributes is
allowed).  Removing an attribute is a special case, for which the new
value passed to the handler is ‘NULL’.

Python supports two pairs of attribute handlers; a type that supports
attributes only needs to implement the functions for one pair.  The
difference is that one pair takes the name of the attribute as a char*,
while the other accepts a *note PyObject: 33a.*.  Each type can use
whichever pair makes more sense for the implementation’s convenience.

     getattrfunc  tp_getattr;        /* char * version */
     setattrfunc  tp_setattr;
     /* ... */
     getattrofunc tp_getattro;       /* PyObject * version */
     setattrofunc tp_setattro;

If accessing attributes of an object is always a simple operation (this
will be explained shortly), there are generic implementations which can
be used to provide the *note PyObject: 33a.* version of the attribute
management functions.  The actual need for type-specific attribute
handlers almost completely disappeared starting with Python 2.2, though
there are many examples which have not been updated to use some of the
new generic mechanism that is available.

* Menu:

* Generic Attribute Management::
* Type-specific Attribute Management::


File: python.info,  Node: Generic Attribute Management,  Next: Type-specific Attribute Management,  Up: Attribute Management

6.2.3.4 Generic Attribute Management
....................................

Most extension types only use 'simple' attributes.  So, what makes the
attributes simple?  There are only a couple of conditions that must be
met:

  1. The name of the attributes must be known when *note PyType_Ready():
     77f. is called.

  2. No special processing is needed to record that an attribute was
     looked up or set, nor do actions need to be taken based on the
     value.

Note that this list does not place any restrictions on the values of the
attributes, when the values are computed, or how relevant data is
stored.

When *note PyType_Ready(): 77f. is called, it uses three tables
referenced by the type object to create *note descriptor: 1677.s which
are placed in the dictionary of the type object.  Each descriptor
controls access to one attribute of the instance object.  Each of the
tables is optional; if all three are ‘NULL’, instances of the type will
only have attributes that are inherited from their base type, and should
leave the *note tp_getattro: 1803. and *note tp_setattro: 4bb2. fields
‘NULL’ as well, allowing the base type to handle attributes.

The tables are declared as three fields of the type object:

     struct PyMethodDef *tp_methods;
     struct PyMemberDef *tp_members;
     struct PyGetSetDef *tp_getset;

If *note tp_methods: 4b9e. is not ‘NULL’, it must refer to an array of
*note PyMethodDef: 1526. structures.  Each entry in the table is an
instance of this structure:

     typedef struct PyMethodDef {
         const char  *ml_name;       /* method name */
         PyCFunction  ml_meth;       /* implementation function */
         int          ml_flags;      /* flags */
         const char  *ml_doc;        /* docstring */
     } PyMethodDef;

One entry should be defined for each method provided by the type; no
entries are needed for methods inherited from a base type.  One
additional entry is needed at the end; it is a sentinel that marks the
end of the array.  The *note ml_name: 4bb3. field of the sentinel must
be ‘NULL’.

The second table is used to define attributes which map directly to data
stored in the instance.  A variety of primitive C types are supported,
and access may be read-only or read-write.  The structures in the table
are defined as:

     typedef struct PyMemberDef {
         const char *name;
         int         type;
         int         offset;
         int         flags;
         const char *doc;
     } PyMemberDef;

For each entry in the table, a *note descriptor: 1677. will be
constructed and added to the type which will be able to extract a value
from the instance structure.  The *note type: 4bb4. field should contain
a type code like *note Py_T_INT: 592. or *note Py_T_DOUBLE: 593.; the
value will be used to determine how to convert Python values to and from
C values.  The *note flags: 4bb5. field is used to store flags which
control how the attribute can be accessed: you can set it to *note
Py_READONLY: 594. to prevent Python code from setting it.

An interesting advantage of using the *note tp_members: 4b9c. table to
build descriptors that are used at runtime is that any attribute defined
this way can have an associated doc string simply by providing the text
in the table.  An application can use the introspection API to retrieve
the descriptor from the class object, and get the doc string using its
*note __doc__: 1e4d. attribute.

As with the *note tp_methods: 4b9e. table, a sentinel entry with a *note
ml_name: 4bb3. value of ‘NULL’ is required.


File: python.info,  Node: Type-specific Attribute Management,  Prev: Generic Attribute Management,  Up: Attribute Management

6.2.3.5 Type-specific Attribute Management
..........................................

For simplicity, only the char* version will be demonstrated here; the
type of the name parameter is the only difference between the char* and
*note PyObject: 33a.* flavors of the interface.  This example
effectively does the same thing as the generic example above, but does
not use the generic support added in Python 2.2.  It explains how the
handler functions are called, so that if you do need to extend their
functionality, you’ll understand what needs to be done.

The *note tp_getattr: 4bb7. handler is called when the object requires
an attribute look-up.  It is called in the same situations where the
*note __getattr__(): 4d6. method of a class would be called.

Here is an example:

     static PyObject *
     newdatatype_getattr(newdatatypeobject *obj, char *name)
     {
         if (strcmp(name, "data") == 0)
         {
             return PyLong_FromLong(obj->data);
         }

         PyErr_Format(PyExc_AttributeError,
                      "'%.100s' object has no attribute '%.400s'",
                      Py_TYPE(obj)->tp_name, name);
         return NULL;
     }

The *note tp_setattr: 4bb8. handler is called when the *note
__setattr__(): 20de. or *note __delattr__(): 20df. method of a class
instance would be called.  When an attribute should be deleted, the
third parameter will be ‘NULL’.  Here is an example that simply raises
an exception; if this were really all you wanted, the ‘tp_setattr’
handler should be set to ‘NULL’.

     static int
     newdatatype_setattr(newdatatypeobject *obj, char *name, PyObject *v)
     {
         PyErr_Format(PyExc_RuntimeError, "Read-only attribute: %s", name);
         return -1;
     }


File: python.info,  Node: Object Comparison,  Next: Abstract Protocol Support,  Prev: Attribute Management,  Up: Defining Extension Types Assorted Topics

6.2.3.6 Object Comparison
.........................

     richcmpfunc tp_richcompare;

The *note tp_richcompare: 4bba. handler is called when comparisons are
needed.  It is analogous to the *note rich comparison methods: 2114,
like ‘__lt__()’, and also called by *note PyObject_RichCompare(): 4bbb.
and *note PyObject_RichCompareBool(): 1b35.

This function is called with two Python objects and the operator as
arguments, where the operator is one of ‘Py_EQ’, ‘Py_NE’, ‘Py_LE’,
‘Py_GE’, ‘Py_LT’ or ‘Py_GT’.  It should compare the two objects with
respect to the specified operator and return ‘Py_True’ or ‘Py_False’ if
the comparison is successful, ‘Py_NotImplemented’ to indicate that
comparison is not implemented and the other object’s comparison method
should be tried, or ‘NULL’ if an exception was set.

Here is a sample implementation, for a datatype that is considered equal
if the size of an internal pointer is equal:

     static PyObject *
     newdatatype_richcmp(newdatatypeobject *obj1, newdatatypeobject *obj2, int op)
     {
         PyObject *result;
         int c, size1, size2;

         /* code to make sure that both arguments are of type
            newdatatype omitted */

         size1 = obj1->obj_UnderlyingDatatypePtr->size;
         size2 = obj2->obj_UnderlyingDatatypePtr->size;

         switch (op) {
         case Py_LT: c = size1 <  size2; break;
         case Py_LE: c = size1 <= size2; break;
         case Py_EQ: c = size1 == size2; break;
         case Py_NE: c = size1 != size2; break;
         case Py_GT: c = size1 >  size2; break;
         case Py_GE: c = size1 >= size2; break;
         }
         result = c ? Py_True : Py_False;
         Py_INCREF(result);
         return result;
      }


File: python.info,  Node: Abstract Protocol Support,  Next: Weak Reference Support,  Prev: Object Comparison,  Up: Defining Extension Types Assorted Topics

6.2.3.7 Abstract Protocol Support
.................................

Python supports a variety of 'abstract' ‘protocols;’ the specific
interfaces provided to use these interfaces are documented in *note
Abstract Objects Layer: 4bbd.

A number of these abstract interfaces were defined early in the
development of the Python implementation.  In particular, the number,
mapping, and sequence protocols have been part of Python since the
beginning.  Other protocols have been added over time.  For protocols
which depend on several handler routines from the type implementation,
the older protocols have been defined as optional blocks of handlers
referenced by the type object.  For newer protocols there are additional
slots in the main type object, with a flag bit being set to indicate
that the slots are present and should be checked by the interpreter.
(The flag bit does not indicate that the slot values are non-‘NULL’.
The flag may be set to indicate the presence of a slot, but a slot may
still be unfilled.)

     PyNumberMethods   *tp_as_number;
     PySequenceMethods *tp_as_sequence;
     PyMappingMethods  *tp_as_mapping;

If you wish your object to be able to act like a number, a sequence, or
a mapping object, then you place the address of a structure that
implements the C type *note PyNumberMethods: 146c, *note
PySequenceMethods: 4bbe, or *note PyMappingMethods: 4bbf, respectively.
It is up to you to fill in this structure with appropriate values.  You
can find examples of the use of each of these in the ‘Objects’ directory
of the Python source distribution.

     hashfunc tp_hash;

This function, if you choose to provide it, should return a hash number
for an instance of your data type.  Here is a simple example:

     static Py_hash_t
     newdatatype_hash(newdatatypeobject *obj)
     {
         Py_hash_t result;
         result = obj->some_size + 32767 * obj->some_number;
         if (result == -1)
            result = -2;
         return result;
     }

*note Py_hash_t: 12aa. is a signed integer type with a platform-varying
width.  Returning ‘-1’ from *note tp_hash: 4bc0. indicates an error,
which is why you should be careful to avoid returning it when hash
computation is successful, as seen above.

     ternaryfunc tp_call;

This function is called when an instance of your data type is “called”,
for example, if ‘obj1’ is an instance of your data type and the Python
script contains ‘obj1('hello')’, the *note tp_call: 55c. handler is
invoked.

This function takes three arguments:

  1. 'self' is the instance of the data type which is the subject of the
     call.  If the call is ‘obj1('hello')’, then 'self' is ‘obj1’.

  2. 'args' is a tuple containing the arguments to the call.  You can
     use *note PyArg_ParseTuple(): 574. to extract the arguments.

  3. 'kwds' is a dictionary of keyword arguments that were passed.  If
     this is non-‘NULL’ and you support keyword arguments, use *note
     PyArg_ParseTupleAndKeywords(): 386. to extract the arguments.  If
     you do not want to support keyword arguments and this is
     non-‘NULL’, raise a *note TypeError: 2c3. with a message saying
     that keyword arguments are not supported.

Here is a toy ‘tp_call’ implementation:

     static PyObject *
     newdatatype_call(newdatatypeobject *obj, PyObject *args, PyObject *kwds)
     {
         PyObject *result;
         const char *arg1;
         const char *arg2;
         const char *arg3;

         if (!PyArg_ParseTuple(args, "sss:call", &arg1, &arg2, &arg3)) {
             return NULL;
         }
         result = PyUnicode_FromFormat(
             "Returning -- value: [%d] arg1: [%s] arg2: [%s] arg3: [%s]\n",
             obj->obj_UnderlyingDatatypePtr->size,
             arg1, arg2, arg3);
         return result;
     }

     /* Iterators */
     getiterfunc tp_iter;
     iternextfunc tp_iternext;

These functions provide support for the iterator protocol.  Both
handlers take exactly one parameter, the instance for which they are
being called, and return a new reference.  In the case of an error, they
should set an exception and return ‘NULL’.  *note tp_iter: 153e.
corresponds to the Python *note __iter__(): c90. method, while *note
tp_iternext: 153f. corresponds to the Python *note __next__(): 1315.
method.

Any *note iterable: 126d. object must implement the *note tp_iter: 153e.
handler, which must return an *note iterator: 1ac. object.  Here the
same guidelines apply as for Python classes:

   * For collections (such as lists and tuples) which can support
     multiple independent iterators, a new iterator should be created
     and returned by each call to *note tp_iter: 153e.

   * Objects which can only be iterated over once (usually due to side
     effects of iteration, such as file objects) can implement *note
     tp_iter: 153e. by returning a new reference to themselves – and
     should also therefore implement the *note tp_iternext: 153f.
     handler.

Any *note iterator: 1ac. object should implement both *note tp_iter:
153e. and *note tp_iternext: 153f.  An iterator’s ‘tp_iter’ handler
should return a new reference to the iterator.  Its ‘tp_iternext’
handler should return a new reference to the next object in the
iteration, if there is one.  If the iteration has reached the end,
‘tp_iternext’ may return ‘NULL’ without setting an exception, or it may
set *note StopIteration: c1b. 'in addition' to returning ‘NULL’;
avoiding the exception can yield slightly better performance.  If an
actual error occurs, ‘tp_iternext’ should always set an exception and
return ‘NULL’.


File: python.info,  Node: Weak Reference Support,  Next: More Suggestions,  Prev: Abstract Protocol Support,  Up: Defining Extension Types Assorted Topics

6.2.3.8 Weak Reference Support
..............................

One of the goals of Python’s weak reference implementation is to allow
any type to participate in the weak reference mechanism without
incurring the overhead on performance-critical objects (such as
numbers).

See also
........

Documentation for the *note weakref: 114. module.

For an object to be weakly referenceable, the extension type must set
the ‘Py_TPFLAGS_MANAGED_WEAKREF’ bit of the *note tp_flags: 1a18. field.
The legacy *note tp_weaklistoffset: 992. field should be left as zero.

Concretely, here is how the statically declared type object would look:

     static PyTypeObject TrivialType = {
         PyVarObject_HEAD_INIT(NULL, 0)
         /* ... other members omitted for brevity ... */
         .tp_flags = Py_TPFLAGS_MANAGED_WEAKREF | ...,
     };

The only further addition is that ‘tp_dealloc’ needs to clear any weak
references (by calling *note PyObject_ClearWeakRefs(): 579.):

     static void
     Trivial_dealloc(TrivialObject *self)
     {
         /* Clear weakrefs first before calling any destructors */
         PyObject_ClearWeakRefs((PyObject *) self);
         /* ... remainder of destruction code omitted for brevity ... */
         Py_TYPE(self)->tp_free((PyObject *) self);
     }


File: python.info,  Node: More Suggestions,  Prev: Weak Reference Support,  Up: Defining Extension Types Assorted Topics

6.2.3.9 More Suggestions
........................

In order to learn how to implement any specific method for your new data
type, get the *note CPython: 6f9. source code.  Go to the ‘Objects’
directory, then search the C source files for ‘tp_’ plus the function
you want (for example, ‘tp_richcompare’).  You will find examples of the
function you want to implement.

When you need to verify that an object is a concrete instance of the
type you are implementing, use the *note PyObject_TypeCheck(): 1a5b.
function.  A sample of its use might be something like the following:

     if (!PyObject_TypeCheck(some_object, &MyType)) {
         PyErr_SetString(PyExc_TypeError, "arg #1 not a mything");
         return NULL;
     }

See also
........

Download CPython source releases.

     ‘https://www.python.org/downloads/source/’

The CPython project on GitHub, where the CPython source code is developed.

     ‘https://github.com/python/cpython’


File: python.info,  Node: Building C and C++ Extensions,  Next: Building C and C++ Extensions on Windows,  Prev: Defining Extension Types Assorted Topics,  Up: Creating extensions without third party tools

6.2.4 Building C and C++ Extensions
-----------------------------------

A C extension for CPython is a shared library (e.g.  a ‘.so’ file on
Linux, ‘.pyd’ on Windows), which exports an 'initialization function'.

To be importable, the shared library must be available on *note
PYTHONPATH: 1058, and must be named after the module name, with an
appropriate extension.  When using setuptools, the correct filename is
generated automatically.

The initialization function has the signature:

 -- C Function: *note PyObject: 33a. *PyInit_modulename (void)

It returns either a fully initialized module, or a *note PyModuleDef:
987. instance.  See *note Initializing C modules: 4bc7. for details.

For modules with ASCII-only names, the function must be named
‘PyInit_<NAME>’, with ‘<name>’ replaced by the name of the module.  When
using *note Multi-phase initialization: 4bc8, non-ASCII module names are
allowed.  In this case, the initialization function name is
‘PyInitU_<NAME>’, with ‘<name>’ encoded using Python’s 'punycode'
encoding with hyphens replaced by underscores.  In Python:

     def initfunc_name(name):
         try:
             suffix = b'_' + name.encode('ascii')
         except UnicodeEncodeError:
             suffix = b'U_' + name.encode('punycode').replace(b'-', b'_')
         return b'PyInit' + suffix

It is possible to export multiple modules from a single shared library
by defining multiple initialization functions.  However, importing them
requires using symbolic links or a custom importer, because by default
only the function corresponding to the filename is found.  See the
'“Multiple modules in one library”' section in PEP 489(1) for details.
* Menu:

* Building C and C++ Extensions with setuptools::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0489/


File: python.info,  Node: Building C and C++ Extensions with setuptools,  Up: Building C and C++ Extensions

6.2.4.1 Building C and C++ Extensions with setuptools
.....................................................

Python 3.12 and newer no longer come with distutils.  Please refer to
the ‘setuptools’ documentation at
‘https://setuptools.readthedocs.io/en/latest/setuptools.html’ to learn
more about how build and distribute C/C++ extensions with setuptools.


File: python.info,  Node: Building C and C++ Extensions on Windows,  Prev: Building C and C++ Extensions,  Up: Creating extensions without third party tools

6.2.5 Building C and C++ Extensions on Windows
----------------------------------------------

This chapter briefly explains how to create a Windows extension module
for Python using Microsoft Visual C++, and follows with more detailed
background information on how it works.  The explanatory material is
useful for both the Windows programmer learning to build Python
extensions and the Unix programmer interested in producing software
which can be successfully built on both Unix and Windows.

Module authors are encouraged to use the distutils approach for building
extension modules, instead of the one described in this section.  You
will still need the C compiler that was used to build Python; typically
Microsoft Visual C++.

     Note: This chapter mentions a number of filenames that include an
     encoded Python version number.  These filenames are represented
     with the version number shown as ‘XY’; in practice, ‘'X'’ will be
     the major version number and ‘'Y'’ will be the minor version number
     of the Python release you’re working with.  For example, if you are
     using Python 2.2.1, ‘XY’ will actually be ‘22’.

* Menu:

* A Cookbook Approach::
* Differences Between Unix and Windows::
* Using DLLs in Practice::


File: python.info,  Node: A Cookbook Approach,  Next: Differences Between Unix and Windows,  Up: Building C and C++ Extensions on Windows

6.2.5.1 A Cookbook Approach
...........................

There are two approaches to building extension modules on Windows, just
as there are on Unix: use the ‘setuptools’ package to control the build
process, or do things manually.  The setuptools approach works well for
most extensions; documentation on using ‘setuptools’ to build and
package extension modules is available in *note Building C and C++
Extensions with setuptools: f2e.  If you find you really need to do
things manually, it may be instructive to study the project file for the
winsound(1) standard library module.

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/PCbuild/winsound.vcxproj


File: python.info,  Node: Differences Between Unix and Windows,  Next: Using DLLs in Practice,  Prev: A Cookbook Approach,  Up: Building C and C++ Extensions on Windows

6.2.5.2 Differences Between Unix and Windows
............................................

Unix and Windows use completely different paradigms for run-time loading
of code.  Before you try to build a module that can be dynamically
loaded, be aware of how your system works.

In Unix, a shared object (‘.so’) file contains code to be used by the
program, and also the names of functions and data that it expects to
find in the program.  When the file is joined to the program, all
references to those functions and data in the file’s code are changed to
point to the actual locations in the program where the functions and
data are placed in memory.  This is basically a link operation.

In Windows, a dynamic-link library (‘.dll’) file has no dangling
references.  Instead, an access to functions or data goes through a
lookup table.  So the DLL code does not have to be fixed up at runtime
to refer to the program’s memory; instead, the code already uses the
DLL’s lookup table, and the lookup table is modified at runtime to point
to the functions and data.

In Unix, there is only one type of library file (‘.a’) which contains
code from several object files (‘.o’).  During the link step to create a
shared object file (‘.so’), the linker may find that it doesn’t know
where an identifier is defined.  The linker will look for it in the
object files in the libraries; if it finds it, it will include all the
code from that object file.

In Windows, there are two types of library, a static library and an
import library (both called ‘.lib’).  A static library is like a Unix
‘.a’ file; it contains code to be included as necessary.  An import
library is basically used only to reassure the linker that a certain
identifier is legal, and will be present in the program when the DLL is
loaded.  So the linker uses the information from the import library to
build the lookup table for using identifiers that are not included in
the DLL. When an application or a DLL is linked, an import library may
be generated, which will need to be used for all future DLLs that depend
on the symbols in the application or DLL.

Suppose you are building two dynamic-load modules, B and C, which should
share another block of code A. On Unix, you would 'not' pass ‘A.a’ to
the linker for ‘B.so’ and ‘C.so’; that would cause it to be included
twice, so that B and C would each have their own copy.  In Windows,
building ‘A.dll’ will also build ‘A.lib’.  You 'do' pass ‘A.lib’ to the
linker for B and C. ‘A.lib’ does not contain code; it just contains
information which will be used at runtime to access A’s code.

In Windows, using an import library is sort of like using ‘import spam’;
it gives you access to spam’s names, but does not create a separate
copy.  On Unix, linking with a library is more like ‘from spam import
*’; it does create a separate copy.


File: python.info,  Node: Using DLLs in Practice,  Prev: Differences Between Unix and Windows,  Up: Building C and C++ Extensions on Windows

6.2.5.3 Using DLLs in Practice
..............................

Windows Python is built in Microsoft Visual C++; using other compilers
may or may not work.  The rest of this section is MSVC++ specific.

When creating DLLs in Windows, you must pass ‘pythonXY.lib’ to the
linker.  To build two DLLs, spam and ni (which uses C functions found in
spam), you could use these commands:

     cl /LD /I/python/include spam.c ../libs/pythonXY.lib
     cl /LD /I/python/include ni.c spam.lib ../libs/pythonXY.lib

The first command created three files: ‘spam.obj’, ‘spam.dll’ and
‘spam.lib’.  ‘Spam.dll’ does not contain any Python functions (such as
*note PyArg_ParseTuple(): 574.), but it does know how to find the Python
code thanks to ‘pythonXY.lib’.

The second command created ‘ni.dll’ (and ‘.obj’ and ‘.lib’), which knows
how to find the necessary functions from spam, and also from the Python
executable.

Not every identifier is exported to the lookup table.  If you want any
other modules (including Python) to be able to see your identifiers, you
have to say ‘_declspec(dllexport)’, as in ‘void _declspec(dllexport)
initspam(void)’ or ‘PyObject _declspec(dllexport) *NiGetSpamData(void)’.

Developer Studio will throw in a lot of import libraries that you do not
really need, adding about 100K to your executable.  To get rid of them,
use the Project Settings dialog, Link tab, to specify 'ignore default
libraries'.  Add the correct ‘msvcrt`xx'.lib’ to the list of libraries.


File: python.info,  Node: Embedding the CPython runtime in a larger application,  Prev: Creating extensions without third party tools,  Up: Extending and Embedding the Python Interpreter

6.3 Embedding the CPython runtime in a larger application
=========================================================

Sometimes, rather than creating an extension that runs inside the Python
interpreter as the main application, it is desirable to instead embed
the CPython runtime inside a larger application.  This section covers
some of the details involved in doing that successfully.

* Menu:

* Embedding Python in Another Application::


File: python.info,  Node: Embedding Python in Another Application,  Up: Embedding the CPython runtime in a larger application

6.3.1 Embedding Python in Another Application
---------------------------------------------

The previous chapters discussed how to extend Python, that is, how to
extend the functionality of Python by attaching a library of C functions
to it.  It is also possible to do it the other way around: enrich your
C/C++ application by embedding Python in it.  Embedding provides your
application with the ability to implement some of the functionality of
your application in Python rather than C or C++.  This can be used for
many purposes; one example would be to allow users to tailor the
application to their needs by writing some scripts in Python.  You can
also use it yourself if some of the functionality can be written in
Python more easily.

Embedding Python is similar to extending it, but not quite.  The
difference is that when you extend Python, the main program of the
application is still the Python interpreter, while if you embed Python,
the main program may have nothing to do with Python — instead, some
parts of the application occasionally call the Python interpreter to run
some Python code.

So if you are embedding Python, you are providing your own main program.
One of the things this main program has to do is initialize the Python
interpreter.  At the very least, you have to call the function *note
Py_Initialize(): 8b4.  There are optional calls to pass command line
arguments to Python.  Then later you can call the interpreter from any
part of the application.

There are several different ways to call the interpreter: you can pass a
string containing Python statements to *note PyRun_SimpleString(): 4bd6,
or you can pass a stdio file pointer and a file name (for identification
in error messages only) to *note PyRun_SimpleFile(): 4bd7.  You can also
call the lower-level operations described in the previous chapters to
construct and use Python objects.

See also
........

*note Python/C API Reference Manual: 1d6f.

     The details of Python’s C interface are given in this manual.  A
     great deal of necessary information can be found here.

* Menu:

* Very High Level Embedding::
* Beyond Very High Level Embedding; An overview: Beyond Very High Level Embedding An overview.
* Pure Embedding::
* Extending Embedded Python::
* Embedding Python in C++::
* Compiling and Linking under Unix-like systems::


File: python.info,  Node: Very High Level Embedding,  Next: Beyond Very High Level Embedding An overview,  Up: Embedding Python in Another Application

6.3.1.1 Very High Level Embedding
.................................

The simplest form of embedding Python is the use of the very high level
interface.  This interface is intended to execute a Python script
without needing to interact with the application directly.  This can for
example be used to perform some operation on a file.

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     int
     main(int argc, char *argv[])
     {
         PyStatus status;
         PyConfig config;
         PyConfig_InitPythonConfig(&config);

         /* optional but recommended */
         status = PyConfig_SetBytesString(&config, &config.program_name, argv[0]);
         if (PyStatus_Exception(status)) {
             goto exception;
         }

         status = Py_InitializeFromConfig(&config);
         if (PyStatus_Exception(status)) {
             goto exception;
         }
         PyConfig_Clear(&config);

         PyRun_SimpleString("from time import time,ctime\n"
                            "print('Today is', ctime(time()))\n");
         if (Py_FinalizeEx() < 0) {
             exit(120);
         }
         return 0;

       exception:
          PyConfig_Clear(&config);
          Py_ExitStatusException(status);
     }

     Note: ‘#define PY_SSIZE_T_CLEAN’ was used to indicate that
     ‘Py_ssize_t’ should be used in some APIs instead of ‘int’.  It is
     not necessary since Python 3.13, but we keep it here for backward
     compatibility.  See *note Strings and buffers: 38e. for a
     description of this macro.

Setting *note PyConfig.program_name: 3c7. should be called before *note
Py_InitializeFromConfig(): 3c8. to inform the interpreter about paths to
Python run-time libraries.  Next, the Python interpreter is initialized
with *note Py_Initialize(): 8b4, followed by the execution of a
hard-coded Python script that prints the date and time.  Afterwards, the
*note Py_FinalizeEx(): d3d. call shuts the interpreter down, followed by
the end of the program.  In a real program, you may want to get the
Python script from another source, perhaps a text-editor routine, a
file, or a database.  Getting the Python code from a file can better be
done by using the *note PyRun_SimpleFile(): 4bd7. function, which saves
you the trouble of allocating memory space and loading the file
contents.


File: python.info,  Node: Beyond Very High Level Embedding An overview,  Next: Pure Embedding,  Prev: Very High Level Embedding,  Up: Embedding Python in Another Application

6.3.1.2 Beyond Very High Level Embedding: An overview
.....................................................

The high level interface gives you the ability to execute arbitrary
pieces of Python code from your application, but exchanging data values
is quite cumbersome to say the least.  If you want that, you should use
lower level calls.  At the cost of having to write more C code, you can
achieve almost anything.

It should be noted that extending Python and embedding Python is quite
the same activity, despite the different intent.  Most topics discussed
in the previous chapters are still valid.  To show this, consider what
the extension code from Python to C really does:

  1. Convert data values from Python to C,

  2. Perform a function call to a C routine using the converted values,
     and

  3. Convert the data values from the call from C to Python.

When embedding Python, the interface code does:

  1. Convert data values from C to Python,

  2. Perform a function call to a Python interface routine using the
     converted values, and

  3. Convert the data values from the call from Python to C.

As you can see, the data conversion steps are simply swapped to
accommodate the different direction of the cross-language transfer.  The
only difference is the routine that you call between both data
conversions.  When extending, you call a C routine, when embedding, you
call a Python routine.

This chapter will not discuss how to convert data from Python to C and
vice versa.  Also, proper use of references and dealing with errors is
assumed to be understood.  Since these aspects do not differ from
extending the interpreter, you can refer to earlier chapters for the
required information.


File: python.info,  Node: Pure Embedding,  Next: Extending Embedded Python,  Prev: Beyond Very High Level Embedding An overview,  Up: Embedding Python in Another Application

6.3.1.3 Pure Embedding
......................

The first program aims to execute a function in a Python script.  Like
in the section about the very high level interface, the Python
interpreter does not directly interact with the application (but that
will change in the next section).

The code to run a function defined in a Python script is:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

     int
     main(int argc, char *argv[])
     {
         PyObject *pName, *pModule, *pFunc;
         PyObject *pArgs, *pValue;
         int i;

         if (argc < 3) {
             fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
             return 1;
         }

         Py_Initialize();
         pName = PyUnicode_DecodeFSDefault(argv[1]);
         /* Error checking of pName left out */

         pModule = PyImport_Import(pName);
         Py_DECREF(pName);

         if (pModule != NULL) {
             pFunc = PyObject_GetAttrString(pModule, argv[2]);
             /* pFunc is a new reference */

             if (pFunc && PyCallable_Check(pFunc)) {
                 pArgs = PyTuple_New(argc - 3);
                 for (i = 0; i < argc - 3; ++i) {
                     pValue = PyLong_FromLong(atoi(argv[i + 3]));
                     if (!pValue) {
                         Py_DECREF(pArgs);
                         Py_DECREF(pModule);
                         fprintf(stderr, "Cannot convert argument\n");
                         return 1;
                     }
                     /* pValue reference stolen here: */
                     PyTuple_SetItem(pArgs, i, pValue);
                 }
                 pValue = PyObject_CallObject(pFunc, pArgs);
                 Py_DECREF(pArgs);
                 if (pValue != NULL) {
                     printf("Result of call: %ld\n", PyLong_AsLong(pValue));
                     Py_DECREF(pValue);
                 }
                 else {
                     Py_DECREF(pFunc);
                     Py_DECREF(pModule);
                     PyErr_Print();
                     fprintf(stderr,"Call failed\n");
                     return 1;
                 }
             }
             else {
                 if (PyErr_Occurred())
                     PyErr_Print();
                 fprintf(stderr, "Cannot find function \"%s\"\n", argv[2]);
             }
             Py_XDECREF(pFunc);
             Py_DECREF(pModule);
         }
         else {
             PyErr_Print();
             fprintf(stderr, "Failed to load \"%s\"\n", argv[1]);
             return 1;
         }
         if (Py_FinalizeEx() < 0) {
             return 120;
         }
         return 0;
     }

This code loads a Python script using ‘argv[1]’, and calls the function
named in ‘argv[2]’.  Its integer arguments are the other values of the
‘argv’ array.  If you *note compile and link: 4bde. this program (let’s
call the finished executable ‘call’), and use it to execute a Python
script, such as:

     def multiply(a,b):
         print("Will compute", a, "times", b)
         c = 0
         for i in range(0, a):
             c = c + b
         return c

then the result should be:

     $ call multiply multiply 3 2
     Will compute 3 times 2
     Result of call: 6

Although the program is quite large for its functionality, most of the
code is for data conversion between Python and C, and for error
reporting.  The interesting part with respect to embedding Python starts
with

     Py_Initialize();
     pName = PyUnicode_DecodeFSDefault(argv[1]);
     /* Error checking of pName left out */
     pModule = PyImport_Import(pName);

After initializing the interpreter, the script is loaded using *note
PyImport_Import(): 144a.  This routine needs a Python string as its
argument, which is constructed using the *note
PyUnicode_DecodeFSDefault(): 1827. data conversion routine.

     pFunc = PyObject_GetAttrString(pModule, argv[2]);
     /* pFunc is a new reference */

     if (pFunc && PyCallable_Check(pFunc)) {
         ...
     }
     Py_XDECREF(pFunc);

Once the script is loaded, the name we’re looking for is retrieved using
*note PyObject_GetAttrString(): 34d.  If the name exists, and the object
returned is callable, you can safely assume that it is a function.  The
program then proceeds by constructing a tuple of arguments as normal.
The call to the Python function is then made with:

     pValue = PyObject_CallObject(pFunc, pArgs);

Upon return of the function, ‘pValue’ is either ‘NULL’ or it contains a
reference to the return value of the function.  Be sure to release the
reference after examining the value.


File: python.info,  Node: Extending Embedded Python,  Next: Embedding Python in C++,  Prev: Pure Embedding,  Up: Embedding Python in Another Application

6.3.1.4 Extending Embedded Python
.................................

Until now, the embedded Python interpreter had no access to
functionality from the application itself.  The Python API allows this
by extending the embedded interpreter.  That is, the embedded
interpreter gets extended with routines provided by the application.
While it sounds complex, it is not so bad.  Simply forget for a while
that the application starts the Python interpreter.  Instead, consider
the application to be a set of subroutines, and write some glue code
that gives Python access to those routines, just like you would write a
normal Python extension.  For example:

     static int numargs=0;

     /* Return the number of arguments of the application command line */
     static PyObject*
     emb_numargs(PyObject *self, PyObject *args)
     {
         if(!PyArg_ParseTuple(args, ":numargs"))
             return NULL;
         return PyLong_FromLong(numargs);
     }

     static PyMethodDef emb_module_methods[] = {
         {"numargs", emb_numargs, METH_VARARGS,
          "Return the number of arguments received by the process."},
         {NULL, NULL, 0, NULL}
     };

     static struct PyModuleDef emb_module = {
         .m_base = PyModuleDef_HEAD_INIT,
         .m_name = "emb",
         .m_size = 0,
         .m_methods = emb_module_methods,
     };

     static PyObject*
     PyInit_emb(void)
     {
         return PyModuleDef_Init(&emb_module);
     }

Insert the above code just above the ‘main()’ function.  Also, insert
the following two statements before the call to *note Py_Initialize():
8b4.:

     numargs = argc;
     PyImport_AppendInittab("emb", &PyInit_emb);

These two lines initialize the ‘numargs’ variable, and make the
‘emb.numargs()’ function accessible to the embedded Python interpreter.
With these extensions, the Python script can do things like

     import emb
     print("Number of arguments", emb.numargs())

In a real application, the methods will expose an API of the application
to Python.


File: python.info,  Node: Embedding Python in C++,  Next: Compiling and Linking under Unix-like systems,  Prev: Extending Embedded Python,  Up: Embedding Python in Another Application

6.3.1.5 Embedding Python in C++
...............................

It is also possible to embed Python in a C++ program; precisely how this
is done will depend on the details of the C++ system used; in general
you will need to write the main program in C++, and use the C++ compiler
to compile and link your program.  There is no need to recompile Python
itself using C++.


File: python.info,  Node: Compiling and Linking under Unix-like systems,  Prev: Embedding Python in C++,  Up: Embedding Python in Another Application

6.3.1.6 Compiling and Linking under Unix-like systems
.....................................................

It is not necessarily trivial to find the right flags to pass to your
compiler (and linker) in order to embed the Python interpreter into your
application, particularly because Python needs to load library modules
implemented as C dynamic extensions (‘.so’ files) linked against it.

To find out the required compiler and linker flags, you can execute the
‘python`X.Y'-config’ script which is generated as part of the
installation process (a ‘python3-config’ script may also be available).
This script has several options, of which the following will be directly
useful to you:

   * ‘pythonX.Y-config --cflags’ will give you the recommended flags
     when compiling:

          $ /opt/bin/python3.11-config --cflags
          -I/opt/include/python3.11 -I/opt/include/python3.11 -Wsign-compare  -DNDEBUG -g -fwrapv -O3 -Wall

   * ‘pythonX.Y-config --ldflags --embed’ will give you the recommended
     flags when linking:

          $ /opt/bin/python3.11-config --ldflags --embed
          -L/opt/lib/python3.11/config-3.11-x86_64-linux-gnu -L/opt/lib -lpython3.11 -lpthread -ldl  -lutil -lm

     Note: To avoid confusion between several Python installations (and
     especially between the system Python and your own compiled Python),
     it is recommended that you use the absolute path to
     ‘python`X.Y'-config’, as in the above example.

If this procedure doesn’t work for you (it is not guaranteed to work for
all Unix-like platforms; however, we welcome *note bug reports: 4be4.)
you will have to read your system’s documentation about dynamic linking
and/or examine Python’s ‘Makefile’ (use *note
sysconfig.get_makefile_filename(): 4638. to find its location) and
compilation options.  In this case, the *note sysconfig: db. module is a
useful tool to programmatically extract the configuration values that
you will want to combine together.  For example:

     >>> import sysconfig
     >>> sysconfig.get_config_var('LIBS')
     '-lpthread -ldl  -lutil'
     >>> sysconfig.get_config_var('LINKFORSHARED')
     '-Xlinker -export-dynamic'


File: python.info,  Node: Python/C API Reference Manual,  Next: Installing Python modules,  Prev: Extending and Embedding the Python Interpreter,  Up: Top

7 Python/C API Reference Manual
*******************************

This manual documents the API used by C and C++ programmers who want to
write extension modules or embed Python.  It is a companion to *note
Extending and Embedding the Python Interpreter: 1d6e, which describes
the general principles of extension writing but does not document the
API functions in detail.

* Menu:

* Introduction: Introduction<13>.
* C API Stability::
* The Very High Level Layer::
* Reference Counting::
* Exception Handling::
* Utilities: Utilities<2>.
* Abstract Objects Layer::
* Concrete Objects Layer::
* Initialization, Finalization, and Threads: Initialization Finalization and Threads.
* Python Initialization Configuration::
* Memory Management::
* Object Implementation Support::
* API and ABI Versioning::
* Monitoring C API::
* Generating Execution Events::


File: python.info,  Node: Introduction<13>,  Next: C API Stability,  Up: Python/C API Reference Manual

7.1 Introduction
================

The Application Programmer’s Interface to Python gives C and C++
programmers access to the Python interpreter at a variety of levels.
The API is equally usable from C++, but for brevity it is generally
referred to as the Python/C API. There are two fundamentally different
reasons for using the Python/C API. The first reason is to write
'extension modules' for specific purposes; these are C modules that
extend the Python interpreter.  This is probably the most common use.
The second reason is to use Python as a component in a larger
application; this technique is generally referred to as 'embedding'
Python in an application.

Writing an extension module is a relatively well-understood process,
where a “cookbook” approach works well.  There are several tools that
automate the process to some extent.  While people have embedded Python
in other applications since its early existence, the process of
embedding Python is less straightforward than writing an extension.

Many API functions are useful independent of whether you’re embedding or
extending Python; moreover, most applications that embed Python will
need to provide a custom extension as well, so it’s probably a good idea
to become familiar with writing an extension before attempting to embed
Python in a real application.

* Menu:

* Coding standards::
* Include Files::
* Useful macros::
* Objects, Types and Reference Counts: Objects Types and Reference Counts.
* Exceptions: Exceptions<21>.
* Embedding Python: Embedding Python<2>.
* Debugging Builds::
* Recommended third party tools: Recommended third party tools<2>.


File: python.info,  Node: Coding standards,  Next: Include Files,  Up: Introduction<13>

7.1.1 Coding standards
----------------------

If you’re writing C code for inclusion in CPython, you 'must' follow the
guidelines and standards defined in PEP 7(1).  These guidelines apply
regardless of the version of Python you are contributing to.  Following
these conventions is not necessary for your own third party extension
modules, unless you eventually expect to contribute them to Python.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0007/


File: python.info,  Node: Include Files,  Next: Useful macros,  Prev: Coding standards,  Up: Introduction<13>

7.1.2 Include Files
-------------------

All function, type and macro definitions needed to use the Python/C API
are included in your code by the following line:

     #define PY_SSIZE_T_CLEAN
     #include <Python.h>

This implies inclusion of the following standard headers: ‘<stdio.h>’,
‘<string.h>’, ‘<errno.h>’, ‘<limits.h>’, ‘<assert.h>’ and ‘<stdlib.h>’
(if available).

     Note: Since Python may define some pre-processor definitions which
     affect the standard headers on some systems, you 'must' include
     ‘Python.h’ before any standard headers are included.

     It is recommended to always define ‘PY_SSIZE_T_CLEAN’ before
     including ‘Python.h’.  See *note Parsing arguments and building
     values: 8b0. for a description of this macro.

All user visible names defined by Python.h (except those defined by the
included standard headers) have one of the prefixes ‘Py’ or ‘_Py’.
Names beginning with ‘_Py’ are for internal use by the Python
implementation and should not be used by extension writers.  Structure
member names do not have a reserved prefix.

     Note: User code should never define names that begin with ‘Py’ or
     ‘_Py’.  This confuses the reader, and jeopardizes the portability
     of the user code to future Python versions, which may define
     additional names beginning with one of these prefixes.

The header files are typically installed with Python.  On Unix, these
are located in the directories ‘`prefix'/include/pythonversion/’ and
‘`exec_prefix'/include/pythonversion/’, where *note prefix: 1f06. and
*note exec_prefix: 1f07. are defined by the corresponding parameters to
Python’s ‘configure’ script and 'version' is ‘'%d.%d' %
sys.version_info[:2]’.  On Windows, the headers are installed in
‘`prefix'/include’, where ‘prefix’ is the installation directory
specified to the installer.

To include the headers, place both directories (if different) on your
compiler’s search path for includes.  Do 'not' place the parent
directories on the search path and then use ‘#include
<pythonX.Y/Python.h>’; this will break on multi-platform builds since
the platform independent headers under *note prefix: 1f06. include the
platform specific headers from *note exec_prefix: 1f07.

C++ users should note that although the API is defined entirely using C,
the header files properly declare the entry points to be ‘extern "C"’.
As a result, there is no need to do anything special to use the API from
C++.


File: python.info,  Node: Useful macros,  Next: Objects Types and Reference Counts,  Prev: Include Files,  Up: Introduction<13>

7.1.3 Useful macros
-------------------

Several useful macros are defined in the Python header files.  Many are
defined closer to where they are useful (e.g.  *note Py_RETURN_NONE:
14c2.).  Others of a more general utility are defined here.  This is not
necessarily a complete listing.

 -- C Macro: PyMODINIT_FUNC

     Declare an extension module ‘PyInit’ initialization function.  The
     function return type is *note PyObject: 33a.*.  The macro declares
     any special linkage declarations required by the platform, and for
     C++ declares the function as ‘extern "C"’.

     The initialization function must be named ‘PyInit_NAME’, where
     'name' is the name of the module, and should be the only
     non-‘static’ item defined in the module file.  Example:

          static struct PyModuleDef spam_module = {
              .m_base = PyModuleDef_HEAD_INIT,
              .m_name = "spam",
              ...
          };

          PyMODINIT_FUNC
          PyInit_spam(void)
          {
              return PyModuleDef_Init(&spam_module);
          }

 -- C Macro: Py_ABS (x)

     Return the absolute value of ‘x’.

     If the result cannot be represented (for example, if ‘x’ has
     ‘INT_MIN’ value for int type), the behavior is undefined.

     Added in version 3.3.

 -- C Macro: Py_ALIGNED (num)

     Specify alignment to 'num' bytes on compilers that support it.

     Consider using the C11 standard ‘_Alignas’ specifier over this
     macro.

 -- C Macro: Py_ARITHMETIC_RIGHT_SHIFT (type, integer, positions)

     Similar to ‘integer >> positions’, but forces sign extension, as
     the C standard does not define whether a right-shift of a signed
     integer will perform sign extension or a zero-fill.

     'integer' should be any signed integer type.  'positions' is the
     number of positions to shift to the right.

     Both 'integer' and 'positions' can be evaluated more than once;
     consequently, avoid directly passing a function call or some other
     operation with side-effects to this macro.  Instead, store the
     result as a variable and then pass it.

     'type' is unused and only kept for backwards compatibility.
     Historically, 'type' was used to cast 'integer'.

     Changed in version 3.1: This macro is now valid for all signed
     integer types, not just those for which ‘unsigned type’ is legal.
     As a result, 'type' is no longer used.

 -- C Macro: Py_ALWAYS_INLINE

     Ask the compiler to always inline a static inline function.  The
     compiler can ignore it and decide to not inline the function.

     It can be used to inline performance critical static inline
     functions when building Python in debug mode with function inlining
     disabled.  For example, MSC disables function inlining when
     building in debug mode.

     Marking blindly a static inline function with Py_ALWAYS_INLINE can
     result in worse performances (due to increased code size for
     example).  The compiler is usually smarter than the developer for
     the cost/benefit analysis.

     If Python is *note built in debug mode: 1f9. (if the *note
     Py_DEBUG: 437b. macro is defined), the *note Py_ALWAYS_INLINE:
     1a11. macro does nothing.

     It must be specified before the function return type.  Usage:

          static inline Py_ALWAYS_INLINE int random(void) { return 4; }

     Added in version 3.11.

 -- C Macro: Py_CAN_START_THREADS

     If this macro is defined, then the current system is able to start
     threads.

     Currently, all systems supported by CPython (per PEP 11(1)), with
     the exception of some WebAssembly platforms, support starting
     threads.

     Added in version 3.13.

 -- C Macro: Py_CHARMASK (c)

     Argument must be a character or an integer in the range [-128, 127]
     or [0, 255].  This macro returns ‘c’ cast to an ‘unsigned char’.

 -- C Macro: Py_DEPRECATED (version)

     Use this for deprecated declarations.  The macro must be placed
     before the symbol name.

     Example:

          Py_DEPRECATED(3.8) PyAPI_FUNC(int) Py_OldFunction(void);

     Changed in version 3.8: MSVC support was added.

 -- C Macro: Py_FORCE_EXPANSION (X)

     This is equivalent to ‘X’, which is useful for token-pasting in
     macros, as macro expansions in 'X' are forcefully evaluated by the
     preprocessor.

 -- C Macro: Py_GCC_ATTRIBUTE (name)

     Use a GCC attribute 'name', hiding it from compilers that don’t
     support GCC attributes (such as MSVC).

     This expands to ‘__attribute__((name))’ on a GCC compiler, and
     expands to nothing on compilers that don’t support GCC attributes.

 -- C Macro: Py_GETENV (s)

     Like ‘getenv(s)’, but returns ‘NULL’ if *note -E: 967. was passed
     on the command line (see *note PyConfig.use_environment: 3dc.).

 -- C Macro: Py_LL (number)

     Use 'number' as a ‘long long’ integer literal.

     This usally expands to 'number' followed by ‘LL’, but will expand
     to some compiler-specific suffixes (such as ‘I64’) on older
     compilers.

     In modern versions of Python, this macro is not very useful, as C99
     and later require the ‘LL’ suffix to be valid for an integer.

 -- C Macro: Py_LOCAL (type)

     Declare a function returning the specified 'type' using a
     fast-calling qualifier for functions that are local to the current
     file.  Semantically, this is equivalent to ‘static type’.

 -- C Macro: Py_LOCAL_INLINE (type)

     Equivalent to *note Py_LOCAL: 1499. but additionally requests the
     function be inlined.

 -- C Macro: Py_LOCAL_SYMBOL

     Macro used to declare a symbol as local to the shared library
     (hidden).  On supported platforms, it ensures the symbol is not
     exported.

     On compatible versions of GCC/Clang, it expands to
     ‘__attribute__((visibility("hidden")))’.

 -- C Macro: Py_MAX (x, y)

     Return the maximum value between ‘x’ and ‘y’.

     Added in version 3.3.

 -- C Macro: Py_MEMBER_SIZE (type, member)

     Return the size of a structure (‘type’) ‘member’ in bytes.

     Added in version 3.6.

 -- C Macro: Py_MIN (x, y)

     Return the minimum value between ‘x’ and ‘y’.

     Added in version 3.3.

 -- C Macro: Py_NO_INLINE

     Disable inlining on a function.  For example, it reduces the C
     stack consumption: useful on LTO+PGO builds which heavily inline
     code (see bpo-33720(2)).

     Usage:

          Py_NO_INLINE static int random(void) { return 4; }

     Added in version 3.11.

 -- C Macro: Py_SAFE_DOWNCAST (value, larger, smaller)

     Cast 'value' to type 'smaller' from type 'larger', validating that
     no information was lost.

     On release builds of Python, this is roughly equivalent to
     ‘(smaller) value’ (in C++, ‘static_cast<smaller>(value)’ will be
     used instead).

     On debug builds (implying that *note Py_DEBUG: 437b. is defined),
     this asserts that no information was lost with the cast from
     'larger' to 'smaller'.

     'value', 'larger', and 'smaller' may all be evaluated more than
     once in the expression; consequently, do not pass an expression
     with side-effects directly to this macro.

 -- C Macro: Py_STRINGIFY (x)

     Convert ‘x’ to a C string.  E.g.  ‘Py_STRINGIFY(123)’ returns
     ‘"123"’.

     Added in version 3.4.

 -- C Macro: Py_ULL (number)

     Similar to *note Py_LL: 4bf6, but 'number' will be an ‘unsigned
     long long’ literal instead.  This is done by appending ‘U’ to the
     result of ‘Py_LL’.

     In modern versions of Python, this macro is not very useful, as C99
     and later require the ‘ULL’/‘LLU’ suffixes to be valid for an
     integer.

 -- C Macro: Py_UNREACHABLE ()

     Use this when you have a code path that cannot be reached by
     design.  For example, in the ‘default:’ clause in a ‘switch’
     statement for which all possible values are covered in ‘case’
     statements.  Use this in places where you might be tempted to put
     an ‘assert(0)’ or ‘abort()’ call.

     In release mode, the macro helps the compiler to optimize the code,
     and avoids a warning about unreachable code.  For example, the
     macro is implemented with ‘__builtin_unreachable()’ on GCC in
     release mode.

     A use for ‘Py_UNREACHABLE()’ is following a call to a function that
     never returns but that is not declared ‘_Py_NO_RETURN’.

     If a code path is very unlikely code but can be reached under
     exceptional case, this macro must not be used.  For example, under
     low memory condition or if a system call returns a value out of the
     expected range.  In this case, it’s better to report the error to
     the caller.  If the error cannot be reported to caller, *note
     Py_FatalError(): 98d. can be used.

     Added in version 3.7.

 -- C Macro: Py_UNUSED (arg)

     Use this for unused arguments in a function definition to silence
     compiler warnings.  Example: ‘int func(int a, int Py_UNUSED(b)) {
     return a; }’.

     Added in version 3.4.

 -- C Macro: Py_BUILD_ASSERT (cond)

     Asserts a compile-time condition 'cond', as a statement.  The build
     will fail if the condition is false or cannot be evaluated at
     compile time.

     For example:

          Py_BUILD_ASSERT(sizeof(PyTime_t) == sizeof(int64_t));

     Added in version 3.3.

 -- C Macro: Py_BUILD_ASSERT_EXPR (cond)

     Asserts a compile-time condition 'cond', as an expression that
     evaluates to ‘0’.  The build will fail if the condition is false or
     cannot be evaluated at compile time.

     For example:

          #define foo_to_char(foo) \
              ((char *)(foo) + Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0))

     Added in version 3.3.

 -- C Macro: PyDoc_STRVAR (name, str)

     Creates a variable with name 'name' that can be used in docstrings.
     If Python is built without docstrings, the value will be empty.

     Use *note PyDoc_STRVAR: 1b04. for docstrings to support building
     Python without docstrings, as specified in PEP 7(3).

     Example:

          PyDoc_STRVAR(pop_doc, "Remove and return the rightmost element.");

          static PyMethodDef deque_methods[] = {
              // ...
              {"pop", (PyCFunction)deque_pop, METH_NOARGS, pop_doc},
              // ...
          }

 -- C Macro: PyDoc_STR (str)

     Creates a docstring for the given input string or an empty string
     if docstrings are disabled.

     Use *note PyDoc_STR: 193c. in specifying docstrings to support
     building Python without docstrings, as specified in PEP 7(4).

     Example:

          static PyMethodDef pysqlite_row_methods[] = {
              {"keys", (PyCFunction)pysqlite_row_keys, METH_NOARGS,
                  PyDoc_STR("Returns the keys of the row.")},
              {NULL, NULL}
          };

 -- C Macro: PyDoc_VAR (name)

     Declares a static character array variable with the given name
     'name'.

     For example:

          PyDoc_VAR(python_doc) = PyDoc_STR("A genus of constricting snakes in the Pythonidae family native "
                                            "to the tropics and subtropics of the Eastern Hemisphere.");

 -- C Macro: Py_ARRAY_LENGTH (array)

     Compute the length of a statically allocated C array at compile
     time.

     The 'array' argument must be a C array with a size known at compile
     time.  Passing an array with an unknown size, such as a
     heap-allocated array, will result in a compilation error on some
     compilers, or otherwise produce incorrect results.

     This is roughly equivalent to:

          sizeof(array) / sizeof((array)[0])

 -- C Macro: Py_EXPORTED_SYMBOL

     Macro used to declare a symbol (function or data) as exported.  On
     Windows, this expands to ‘__declspec(dllexport)’.  On compatible
     versions of GCC/Clang, it expands to
     ‘__attribute__((visibility("default")))’.  This macro is for
     defining the C API itself; extension modules should not use it.

 -- C Macro: Py_IMPORTED_SYMBOL

     Macro used to declare a symbol as imported.  On Windows, this
     expands to ‘__declspec(dllimport)’.  This macro is for defining the
     C API itself; extension modules should not use it.

 -- C Macro: PyAPI_FUNC (type)

     Macro used by CPython to declare a function as part of the C API.
     Its expansion depends on the platform and build configuration.
     This macro is intended for defining CPython’s C API itself;
     extension modules should not use it for their own symbols.

 -- C Macro: PyAPI_DATA (type)

     Macro used by CPython to declare a public global variable as part
     of the C API. Its expansion depends on the platform and build
     configuration.  This macro is intended for defining CPython’s C API
     itself; extension modules should not use it for their own symbols.

 -- C Macro: Py_VA_COPY

     This is a *note soft deprecated: 209. alias to the C99-standard
     ‘va_copy’ function.

     Historically, this would use a compiler-specific method to copy a
     ‘va_list’.

     Changed in version 3.6: This is now an alias to ‘va_copy’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0011/

   (2) https://bugs.python.org/issue?@action=redirect&bpo=33720

   (3) https://peps.python.org/pep-0007/

   (4) https://peps.python.org/pep-0007/


File: python.info,  Node: Objects Types and Reference Counts,  Next: Exceptions<21>,  Prev: Useful macros,  Up: Introduction<13>

7.1.4 Objects, Types and Reference Counts
-----------------------------------------

Most Python/C API functions have one or more arguments as well as a
return value of type *note PyObject: 33a.*.  This type is a pointer to
an opaque data type representing an arbitrary Python object.  Since all
Python object types are treated the same way by the Python language in
most situations (e.g., assignments, scope rules, and argument passing),
it is only fitting that they should be represented by a single C type.
Almost all Python objects live on the heap: you never declare an
automatic or static variable of type *note PyObject: 33a, only pointer
variables of type PyObject* can be declared.  The sole exception are the
type objects; since these must never be deallocated, they are typically
static *note PyTypeObject: aba. objects.

All Python objects (even Python integers) have a 'type' and a 'reference
count'.  An object’s type determines what kind of object it is (e.g., an
integer, a list, or a user-defined function; there are many more as
explained in *note The standard type hierarchy: 2094.).  For each of the
well-known types there is a macro to check whether an object is of that
type; for instance, ‘PyList_Check(a)’ is true if (and only if) the
object pointed to by 'a' is a Python list.

* Menu:

* Reference Counts: Reference Counts<2>.
* Types::


File: python.info,  Node: Reference Counts<2>,  Next: Types,  Up: Objects Types and Reference Counts

7.1.4.1 Reference Counts
........................

The reference count is important because today’s computers have a finite
(and often severely limited) memory size; it counts how many different
places there are that have a *note strong reference: 33e. to an object.
Such a place could be another object, or a global (or static) C
variable, or a local variable in some C function.  When the last strong
reference to an object is released (i.e.  its reference count becomes
zero), the object is deallocated.  If it contains references to other
objects, those references are released.  Those other objects may be
deallocated in turn, if there are no more references to them, and so on.
(There’s an obvious problem with objects that reference each other here;
for now, the solution is “don’t do that.”)

Reference counts are always manipulated explicitly.  The normal way is
to use the macro *note Py_INCREF(): 571. to take a new reference to an
object (i.e.  increment its reference count by one), and *note
Py_DECREF(): 572. to release that reference (i.e.  decrement the
reference count by one).  The ‘Py_DECREF()’ macro is considerably more
complex than the incref one, since it must check whether the reference
count becomes zero and then cause the object’s deallocator to be called.
The deallocator is a function pointer contained in the object’s type
structure.  The type-specific deallocator takes care of releasing
references for other objects contained in the object if this is a
compound object type, such as a list, as well as performing any
additional finalization that’s needed.  There’s no chance that the
reference count can overflow; at least as many bits are used to hold the
reference count as there are distinct memory locations in virtual memory
(assuming ‘sizeof(Py_ssize_t) >= sizeof(void*)’).  Thus, the reference
count increment is a simple operation.

It is not necessary to hold a *note strong reference: 33e. (i.e.
increment the reference count) for every local variable that contains a
pointer to an object.  In theory, the object’s reference count goes up
by one when the variable is made to point to it and it goes down by one
when the variable goes out of scope.  However, these two cancel each
other out, so at the end the reference count hasn’t changed.  The only
real reason to use the reference count is to prevent the object from
being deallocated as long as our variable is pointing to it.  If we know
that there is at least one other reference to the object that lives at
least as long as our variable, there is no need to take a new strong
reference (i.e.  increment the reference count) temporarily.  An
important situation where this arises is in objects that are passed as
arguments to C functions in an extension module that are called from
Python; the call mechanism guarantees to hold a reference to every
argument for the duration of the call.

However, a common pitfall is to extract an object from a list and hold
on to it for a while without taking a new reference.  Some other
operation might conceivably remove the object from the list, releasing
that reference, and possibly deallocating it.  The real danger is that
innocent-looking operations may invoke arbitrary Python code which could
do this; there is a code path which allows control to flow back to the
user from a *note Py_DECREF(): 572, so almost any operation is
potentially dangerous.

A safe approach is to always use the generic operations (functions whose
name begins with ‘PyObject_’, ‘PyNumber_’, ‘PySequence_’ or
‘PyMapping_’).  These operations always create a new *note strong
reference: 33e. (i.e.  increment the reference count) of the object they
return.  This leaves the caller with the responsibility to call *note
Py_DECREF(): 572. when they are done with the result; this soon becomes
second nature.

* Menu:

* Reference Count Details::


File: python.info,  Node: Reference Count Details,  Up: Reference Counts<2>

7.1.4.2 Reference Count Details
...............................

The reference count behavior of functions in the Python/C API is best
explained in terms of 'ownership of references'.  Ownership pertains to
references, never to objects (objects are not owned: they are always
shared).  “Owning a reference” means being responsible for calling
Py_DECREF on it when the reference is no longer needed.  Ownership can
also be transferred, meaning that the code that receives ownership of
the reference then becomes responsible for eventually releasing it by
calling *note Py_DECREF(): 572. or *note Py_XDECREF(): 792. when it’s no
longer needed—or passing on this responsibility (usually to its caller).
When a function passes ownership of a reference on to its caller, the
caller is said to receive a 'new' reference.  When no ownership is
transferred, the caller is said to 'borrow' the reference.  Nothing
needs to be done for a *note borrowed reference: 33f.

Conversely, when a calling function passes in a reference to an object,
there are two possibilities: the function 'steals' a reference to the
object, or it does not.  'Stealing a reference' means that when you pass
a reference to a function, that function assumes that it now owns that
reference, and you are not responsible for it any longer.

Few functions steal references; the two notable exceptions are *note
PyList_SetItem(): 167d. and *note PyTuple_SetItem(): 4b83, which steal a
reference to the item (but not to the tuple or list into which the item
is put!).  These functions were designed to steal a reference because of
a common idiom for populating a tuple or list with newly created
objects; for example, the code to create the tuple ‘(1, 2, "three")’
could look like this (forgetting about error handling for the moment; a
better way to code this is shown below):

     PyObject *t;

     t = PyTuple_New(3);
     PyTuple_SetItem(t, 0, PyLong_FromLong(1L));
     PyTuple_SetItem(t, 1, PyLong_FromLong(2L));
     PyTuple_SetItem(t, 2, PyUnicode_FromString("three"));

Here, *note PyLong_FromLong(): 1975. returns a new reference which is
immediately stolen by *note PyTuple_SetItem(): 4b83.  When you want to
keep using an object although the reference to it will be stolen, use
*note Py_INCREF(): 571. to grab another reference before calling the
reference-stealing function.

Incidentally, *note PyTuple_SetItem(): 4b83. is the 'only' way to set
tuple items; *note PySequence_SetItem(): 1be6. and *note
PyObject_SetItem(): 4c0a. refuse to do this since tuples are an
immutable data type.  You should only use ‘PyTuple_SetItem()’ for tuples
that you are creating yourself.

Equivalent code for populating a list can be written using *note
PyList_New(): 4c0b. and *note PyList_SetItem(): 167d.

However, in practice, you will rarely use these ways of creating and
populating a tuple or list.  There’s a generic function, *note
Py_BuildValue(): 8af, that can create most common objects from C values,
directed by a 'format string'.  For example, the above two blocks of
code could be replaced by the following (which also takes care of the
error checking):

     PyObject *tuple, *list;

     tuple = Py_BuildValue("(iis)", 1, 2, "three");
     list = Py_BuildValue("[iis]", 1, 2, "three");

It is much more common to use *note PyObject_SetItem(): 4c0a. and
friends with items whose references you are only borrowing, like
arguments that were passed in to the function you are writing.  In that
case, their behaviour regarding references is much saner, since you
don’t have to take a new reference just so you can give that reference
away (“have it be stolen”).  For example, this function sets all items
of a list (actually, any mutable sequence) to a given item:

     int
     set_all(PyObject *target, PyObject *item)
     {
         Py_ssize_t i, n;

         n = PyObject_Length(target);
         if (n < 0)
             return -1;
         for (i = 0; i < n; i++) {
             PyObject *index = PyLong_FromSsize_t(i);
             if (!index)
                 return -1;
             if (PyObject_SetItem(target, index, item) < 0) {
                 Py_DECREF(index);
                 return -1;
             }
             Py_DECREF(index);
         }
         return 0;
     }

The situation is slightly different for function return values.  While
passing a reference to most functions does not change your ownership
responsibilities for that reference, many functions that return a
reference to an object give you ownership of the reference.  The reason
is simple: in many cases, the returned object is created on the fly, and
the reference you get is the only reference to the object.  Therefore,
the generic functions that return object references, like *note
PyObject_GetItem(): 348. and *note PySequence_GetItem(): 1be5, always
return a new reference (the caller becomes the owner of the reference).

It is important to realize that whether you own a reference returned by
a function depends on which function you call only — 'the plumage' (the
type of the object passed as an argument to the function) 'doesn’t enter
into it!'  Thus, if you extract an item from a list using *note
PyList_GetItem(): 35d, you don’t own the reference — but if you obtain
the same item from the same list using *note PySequence_GetItem(): 1be5.
(which happens to take exactly the same arguments), you do own a
reference to the returned object.

Here is an example of how you could write a function that computes the
sum of the items in a list of integers; once using *note
PyList_GetItem(): 35d, and once using *note PySequence_GetItem(): 1be5.

     long
     sum_list(PyObject *list)
     {
         Py_ssize_t i, n;
         long total = 0, value;
         PyObject *item;

         n = PyList_Size(list);
         if (n < 0)
             return -1; /* Not a list */
         for (i = 0; i < n; i++) {
             item = PyList_GetItem(list, i); /* Can't fail */
             if (!PyLong_Check(item)) continue; /* Skip non-integers */
             value = PyLong_AsLong(item);
             if (value == -1 && PyErr_Occurred())
                 /* Integer too big to fit in a C long, bail out */
                 return -1;
             total += value;
         }
         return total;
     }

     long
     sum_sequence(PyObject *sequence)
     {
         Py_ssize_t i, n;
         long total = 0, value;
         PyObject *item;
         n = PySequence_Length(sequence);
         if (n < 0)
             return -1; /* Has no length */
         for (i = 0; i < n; i++) {
             item = PySequence_GetItem(sequence, i);
             if (item == NULL)
                 return -1; /* Not a sequence, or other failure */
             if (PyLong_Check(item)) {
                 value = PyLong_AsLong(item);
                 Py_DECREF(item);
                 if (value == -1 && PyErr_Occurred())
                     /* Integer too big to fit in a C long, bail out */
                     return -1;
                 total += value;
             }
             else {
                 Py_DECREF(item); /* Discard reference ownership */
             }
         }
         return total;
     }


File: python.info,  Node: Types,  Prev: Reference Counts<2>,  Up: Objects Types and Reference Counts

7.1.4.3 Types
.............

There are few other data types that play a significant role in the
Python/C API; most are simple C types such as int, long, double and
char*.  A few structure types are used to describe static tables used to
list the functions exported by a module or the data attributes of a new
object type, and another is used to describe the value of a complex
number.  These will be discussed together with the functions that use
them.

 -- C Type: type Py_ssize_t
     ' Part of the *note Stable ABI: 556.'  A signed integral type such
     that ‘sizeof(Py_ssize_t) == sizeof(size_t)’.  C99 doesn’t define
     such a thing directly (size_t is an unsigned integral type).  See
     PEP 353(1) for details.  ‘PY_SSIZE_T_MAX’ is the largest positive
     value of type *note Py_ssize_t: a6e.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0353/


File: python.info,  Node: Exceptions<21>,  Next: Embedding Python<2>,  Prev: Objects Types and Reference Counts,  Up: Introduction<13>

7.1.5 Exceptions
----------------

The Python programmer only needs to deal with exceptions if specific
error handling is required; unhandled exceptions are automatically
propagated to the caller, then to the caller’s caller, and so on, until
they reach the top-level interpreter, where they are reported to the
user accompanied by a stack traceback.

For C programmers, however, error checking always has to be explicit.
All functions in the Python/C API can raise exceptions, unless an
explicit claim is made otherwise in a function’s documentation.  In
general, when a function encounters an error, it sets an exception,
discards any object references that it owns, and returns an error
indicator.  If not documented otherwise, this indicator is either ‘NULL’
or ‘-1’, depending on the function’s return type.  A few functions
return a Boolean true/false result, with false indicating an error.
Very few functions return no explicit error indicator or have an
ambiguous return value, and require explicit testing for errors with
*note PyErr_Occurred(): 1a55.  These exceptions are always explicitly
documented.

Exception state is maintained in per-thread storage (this is equivalent
to using global storage in an unthreaded application).  A thread can be
in one of two states: an exception has occurred, or not.  The function
*note PyErr_Occurred(): 1a55. can be used to check for this: it returns
a borrowed reference to the exception type object when an exception has
occurred, and ‘NULL’ otherwise.  There are a number of functions to set
the exception state: *note PyErr_SetString(): 57f. is the most common
(though not the most general) function to set the exception state, and
*note PyErr_Clear(): 106e. clears the exception state.

The full exception state consists of three objects (all of which can be
‘NULL’): the exception type, the corresponding exception value, and the
traceback.  These have the same meanings as the Python result of
‘sys.exc_info()’; however, they are not the same: the Python objects
represent the last exception being handled by a Python *note try: 6ec. …
*note except: 18b. statement, while the C level exception state only
exists while an exception is being passed on between C functions until
it reaches the Python bytecode interpreter’s main loop, which takes care
of transferring it to ‘sys.exc_info()’ and friends.

Note that starting with Python 1.5, the preferred, thread-safe way to
access the exception state from Python code is to call the function
*note sys.exc_info(): 68d, which returns the per-thread exception state
for Python code.  Also, the semantics of both ways to access the
exception state have changed so that a function which catches an
exception will save and restore its thread’s exception state so as to
preserve the exception state of its caller.  This prevents common bugs
in exception handling code caused by an innocent-looking function
overwriting the exception being handled; it also reduces the often
unwanted lifetime extension for objects that are referenced by the stack
frames in the traceback.

As a general principle, a function that calls another function to
perform some task should check whether the called function raised an
exception, and if so, pass the exception state on to its caller.  It
should discard any object references that it owns, and return an error
indicator, but it should 'not' set another exception — that would
overwrite the exception that was just raised, and lose important
information about the exact cause of the error.

A simple example of detecting exceptions and passing them on is shown in
the ‘sum_sequence()’ example above.  It so happens that this example
doesn’t need to clean up any owned references when it detects an error.
The following example function shows some error cleanup.  First, to
remind you why you like Python, we show the equivalent Python code:

     def incr_item(dict, key):
         try:
             item = dict[key]
         except KeyError:
             item = 0
         dict[key] = item + 1

Here is the corresponding C code, in all its glory:

     int
     incr_item(PyObject *dict, PyObject *key)
     {
         /* Objects all initialized to NULL for Py_XDECREF */
         PyObject *item = NULL, *const_one = NULL, *incremented_item = NULL;
         int rv = -1; /* Return value initialized to -1 (failure) */

         item = PyObject_GetItem(dict, key);
         if (item == NULL) {
             /* Handle KeyError only: */
             if (!PyErr_ExceptionMatches(PyExc_KeyError))
                 goto error;

             /* Clear the error and use zero: */
             PyErr_Clear();
             item = PyLong_FromLong(0L);
             if (item == NULL)
                 goto error;
         }
         const_one = PyLong_FromLong(1L);
         if (const_one == NULL)
             goto error;

         incremented_item = PyNumber_Add(item, const_one);
         if (incremented_item == NULL)
             goto error;

         if (PyObject_SetItem(dict, key, incremented_item) < 0)
             goto error;
         rv = 0; /* Success */
         /* Continue with cleanup code */

      error:
         /* Cleanup code, shared by success and failure path */

         /* Use Py_XDECREF() to ignore NULL references */
         Py_XDECREF(item);
         Py_XDECREF(const_one);
         Py_XDECREF(incremented_item);

         return rv; /* -1 for error, 0 for success */
     }

This example represents an endorsed use of the ‘goto’ statement in C! It
illustrates the use of *note PyErr_ExceptionMatches(): 4c10. and *note
PyErr_Clear(): 106e. to handle specific exceptions, and the use of *note
Py_XDECREF(): 792. to dispose of owned references that may be ‘NULL’
(note the ‘'X'’ in the name; *note Py_DECREF(): 572. would crash when
confronted with a ‘NULL’ reference).  It is important that the variables
used to hold owned references are initialized to ‘NULL’ for this to
work; likewise, the proposed return value is initialized to ‘-1’
(failure) and only set to success after the final call made is
successful.


File: python.info,  Node: Embedding Python<2>,  Next: Debugging Builds,  Prev: Exceptions<21>,  Up: Introduction<13>

7.1.6 Embedding Python
----------------------

The one important task that only embedders (as opposed to extension
writers) of the Python interpreter have to worry about is the
initialization, and possibly the finalization, of the Python
interpreter.  Most functionality of the interpreter can only be used
after the interpreter has been initialized.

The basic initialization function is *note Py_Initialize(): 8b4.  This
initializes the table of loaded modules, and creates the fundamental
modules *note builtins: 12, *note __main__: 1, and *note sys: d9.  It
also initializes the module search path (‘sys.path’).

*note Py_Initialize(): 8b4. does not set the “script argument list”
(‘sys.argv’).  If this variable is needed by Python code that will be
executed later, setting *note PyConfig.argv: 3c6. and *note
PyConfig.parse_argv: 1a98. must be set: see *note Python Initialization
Configuration: 3aa.

On most systems (in particular, on Unix and Windows, although the
details are slightly different), *note Py_Initialize(): 8b4. calculates
the module search path based upon its best guess for the location of the
standard Python interpreter executable, assuming that the Python library
is found in a fixed location relative to the Python interpreter
executable.  In particular, it looks for a directory named
‘lib/python`X.Y'’ relative to the parent directory where the executable
named ‘python’ is found on the shell command search path (the
environment variable ‘PATH’).

For instance, if the Python executable is found in
‘/usr/local/bin/python’, it will assume that the libraries are in
‘/usr/local/lib/python`X.Y'’.  (In fact, this particular path is also
the “fallback” location, used when no executable file named ‘python’ is
found along ‘PATH’.)  The user can override this behavior by setting the
environment variable *note PYTHONHOME: 3bf, or insert additional
directories in front of the standard path by setting *note PYTHONPATH:
1058.

The embedding application can steer the search by setting *note
PyConfig.program_name: 3c7. 'before' calling *note
Py_InitializeFromConfig(): 3c8.  Note that *note PYTHONHOME: 3bf. still
overrides this and *note PYTHONPATH: 1058. is still inserted in front of
the standard path.  An application that requires total control has to
provide its own implementation of *note Py_GetPath(): 3b6, *note
Py_GetPrefix(): 3b8, *note Py_GetExecPrefix(): 3b4, and *note
Py_GetProgramFullPath(): 3ba. (all defined in ‘Modules/getpath.c’).

Sometimes, it is desirable to “uninitialize” Python.  For instance, the
application may want to start over (make another call to *note
Py_Initialize(): 8b4.) or the application is simply done with its use of
Python and wants to free memory allocated by Python.  This can be
accomplished by calling *note Py_FinalizeEx(): d3d.  The function *note
Py_IsInitialized(): 4c13. returns true if Python is currently in the
initialized state.  More information about these functions is given in a
later chapter.  Notice that ‘Py_FinalizeEx()’ does 'not' free all memory
allocated by the Python interpreter, e.g.  memory allocated by extension
modules currently cannot be released.


File: python.info,  Node: Debugging Builds,  Next: Recommended third party tools<2>,  Prev: Embedding Python<2>,  Up: Introduction<13>

7.1.7 Debugging Builds
----------------------

Python can be built with several macros to enable extra checks of the
interpreter and extension modules.  These checks tend to add a large
amount of overhead to the runtime so they are not enabled by default.

A full list of the various types of debugging builds is in the file
‘Misc/SpecialBuilds.txt’ in the Python source distribution.  Builds are
available that support tracing of reference counts, debugging the memory
allocator, or low-level profiling of the main interpreter loop.  Only
the most frequently used builds will be described in the remainder of
this section.

 -- C Macro: Py_DEBUG

Compiling the interpreter with the ‘Py_DEBUG’ macro defined produces
what is generally meant by *note a debug build of Python: 1f9.
‘Py_DEBUG’ is enabled in the Unix build by adding *note -with-pydebug:
427. to the ‘./configure’ command.  It is also implied by the presence
of the not-Python-specific ‘_DEBUG’ macro.  When ‘Py_DEBUG’ is enabled
in the Unix build, compiler optimization is disabled.

In addition to the reference count debugging described below, extra
checks are performed, see *note Python Debug Build: 1f9.

Defining ‘Py_TRACE_REFS’ enables reference tracing (see the *note
configure -with-trace-refs option: 398.).  When defined, a circular
doubly linked list of active objects is maintained by adding two extra
fields to every *note PyObject: 33a.  Total allocations are tracked as
well.  Upon exit, all existing references are printed.  (In interactive
mode this happens after every statement run by the interpreter.)

Please refer to ‘Misc/SpecialBuilds.txt’ in the Python source
distribution for more detailed information.


File: python.info,  Node: Recommended third party tools<2>,  Prev: Debugging Builds,  Up: Introduction<13>

7.1.8 Recommended third party tools
-----------------------------------

The following third party tools offer both simpler and more
sophisticated approaches to creating C, C++ and Rust extensions for
Python:

   * Cython(1)

   * cffi(2)

   * HPy(3)

   * nanobind(4) (C++)

   * Numba(5)

   * pybind11(6) (C++)

   * PyO3(7) (Rust)

   * SWIG(8)

Using tools such as these can help avoid writing code that is tightly
bound to a particular version of CPython, avoid reference counting
errors, and focus more on your own code than on using the CPython API.
In general, new versions of Python can be supported by updating the
tool, and your code will often use newer and more efficient APIs
automatically.  Some tools also support compiling for other
implementations of Python from a single set of sources.

These projects are not supported by the same people who maintain Python,
and issues need to be raised with the projects directly.  Remember to
check that the project is still maintained and supported, as the list
above may become outdated.

See also
........

Python Packaging User Guide: Binary Extensions(9)

     The Python Packaging User Guide not only covers several available
     tools that simplify the creation of binary extensions, but also
     discusses the various reasons why creating an extension module may
     be desirable in the first place.

   ---------- Footnotes ----------

   (1) https://cython.org/

   (2) https://cffi.readthedocs.io

   (3) https://hpyproject.org/

   (4) https://github.com/wjakob/nanobind

   (5) https://numba.pydata.org/

   (6) https://pybind11.readthedocs.io/

   (7) https://pyo3.rs/

   (8) https://www.swig.org

   (9) https://packaging.python.org/guides/packaging-binary-extensions/


File: python.info,  Node: C API Stability,  Next: The Very High Level Layer,  Prev: Introduction<13>,  Up: Python/C API Reference Manual

7.2 C API Stability
===================

Unless documented otherwise, Python’s C API is covered by the Backwards
Compatibility Policy, PEP 387(1).  Most changes to it are
source-compatible (typically by only adding new API). Changing existing
API or removing API is only done after a deprecation period or to fix
serious issues.

CPython’s Application Binary Interface (ABI) is forward- and
backwards-compatible across a minor release (if these are compiled the
same way; see *note Platform Considerations: 4c1a. below).  So, code
compiled for Python 3.10.0 will work on 3.10.8 and vice versa, but will
need to be compiled separately for 3.9.x and 3.11.x.

There are two tiers of C API with different stability expectations:

   - *note Unstable API: 54a, may change in minor versions without a
     deprecation period.  It is marked by the ‘PyUnstable’ prefix in
     names.

   - *note Limited API: 399, is compatible across several minor
     releases.  When *note Py_LIMITED_API: 421. is defined, only this
     subset is exposed from ‘Python.h’.

These are discussed in more detail below.

Names prefixed by an underscore, such as ‘_Py_InternalState’, are
private API that can change without notice even in patch releases.  If
you need to use this API, consider reaching out to CPython developers(2)
to discuss adding public API for your use case.

* Menu:

* Unstable C API::
* Stable Application Binary Interface::
* Platform Considerations::
* Contents of Limited API::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0387/

   (2) https://discuss.python.org/c/core-dev/c-api/30


File: python.info,  Node: Unstable C API,  Next: Stable Application Binary Interface,  Up: C API Stability

7.2.1 Unstable C API
--------------------

Any API named with the ‘PyUnstable’ prefix exposes CPython
implementation details, and may change in every minor release (e.g.
from 3.9 to 3.10) without any deprecation warnings.  However, it will
not change in a bugfix release (e.g.  from 3.10.0 to 3.10.1).

It is generally intended for specialized, low-level tools like
debuggers.

Projects that use this API are expected to follow CPython development
and spend extra effort adjusting to changes.


File: python.info,  Node: Stable Application Binary Interface,  Next: Platform Considerations,  Prev: Unstable C API,  Up: C API Stability

7.2.2 Stable Application Binary Interface
-----------------------------------------

For simplicity, this document talks about 'extensions', but the Limited
API and Stable ABI work the same way for all uses of the API – for
example, embedding Python.

* Menu:

* Limited C API::
* Stable ABI::
* Limited API Scope and Performance::
* Limited API Caveats::


File: python.info,  Node: Limited C API,  Next: Stable ABI,  Up: Stable Application Binary Interface

7.2.2.1 Limited C API
.....................

Python 3.2 introduced the 'Limited API', a subset of Python’s C API.
Extensions that only use the Limited API can be compiled once and be
loaded on multiple versions of Python.  Contents of the Limited API are
*note listed below: 79d.

 -- C Macro: Py_LIMITED_API

     Define this macro before including ‘Python.h’ to opt in to only use
     the Limited API, and to select the Limited API version.

     Define ‘Py_LIMITED_API’ to the value of *note PY_VERSION_HEX: 75a.
     corresponding to the lowest Python version your extension supports.
     The extension will be ABI-compatible with all Python 3 releases
     from the specified one onward, and can use Limited API introduced
     up to that version.

     Rather than using the ‘PY_VERSION_HEX’ macro directly, hardcode a
     minimum minor version (e.g.  ‘0x030A0000’ for Python 3.10) for
     stability when compiling with future Python versions.

     You can also define ‘Py_LIMITED_API’ to ‘3’.  This works the same
     as ‘0x03020000’ (Python 3.2, the version that introduced Limited
     API).


File: python.info,  Node: Stable ABI,  Next: Limited API Scope and Performance,  Prev: Limited C API,  Up: Stable Application Binary Interface

7.2.2.2 Stable ABI
..................

To enable this, Python provides a 'Stable ABI': a set of symbols that
will remain ABI-compatible across Python 3.x versions.

     Note: The Stable ABI prevents ABI issues, like linker errors due to
     missing symbols or data corruption due to changes in structure
     layouts or function signatures.  However, other changes in Python
     can change the 'behavior' of extensions.  See Python’s Backwards
     Compatibility Policy ( PEP 387(1)) for details.

The Stable ABI contains symbols exposed in the *note Limited API: 399,
but also other ones – for example, functions necessary to support older
versions of the Limited API.

On Windows, extensions that use the Stable ABI should be linked against
‘python3.dll’ rather than a version-specific library such as
‘python39.dll’.

On some platforms, Python will look for and load shared library files
named with the ‘abi3’ tag (e.g.  ‘mymodule.abi3.so’).  It does not check
if such extensions conform to a Stable ABI. The user (or their packaging
tools) need to ensure that, for example, extensions built with the 3.10+
Limited API are not installed for lower versions of Python.

All functions in the Stable ABI are present as functions in Python’s
shared library, not solely as macros.  This makes them usable from
languages that don’t use the C preprocessor.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0387/


File: python.info,  Node: Limited API Scope and Performance,  Next: Limited API Caveats,  Prev: Stable ABI,  Up: Stable Application Binary Interface

7.2.2.3 Limited API Scope and Performance
.........................................

The goal for the Limited API is to allow everything that is possible
with the full C API, but possibly with a performance penalty.

For example, while *note PyList_GetItem(): 35d. is available, its
“unsafe” macro variant *note PyList_GET_ITEM(): 4c21. is not.  The macro
can be faster because it can rely on version-specific implementation
details of the list object.

Without ‘Py_LIMITED_API’ defined, some C API functions are inlined or
replaced by macros.  Defining ‘Py_LIMITED_API’ disables this inlining,
allowing stability as Python’s data structures are improved, but
possibly reducing performance.

By leaving out the ‘Py_LIMITED_API’ definition, it is possible to
compile a Limited API extension with a version-specific ABI. This can
improve performance for that Python version, but will limit
compatibility.  Compiling with ‘Py_LIMITED_API’ will then yield an
extension that can be distributed where a version-specific one is not
available – for example, for prereleases of an upcoming Python version.


File: python.info,  Node: Limited API Caveats,  Prev: Limited API Scope and Performance,  Up: Stable Application Binary Interface

7.2.2.4 Limited API Caveats
...........................

Note that compiling with ‘Py_LIMITED_API’ is 'not' a complete guarantee
that code conforms to the *note Limited API: 399. or the *note Stable
ABI: 4c1f.  ‘Py_LIMITED_API’ only covers definitions, but an API also
includes other issues, such as expected semantics.

One issue that ‘Py_LIMITED_API’ does not guard against is calling a
function with arguments that are invalid in a lower Python version.  For
example, consider a function that starts accepting ‘NULL’ for an
argument.  In Python 3.9, ‘NULL’ now selects a default behavior, but in
Python 3.8, the argument will be used directly, causing a ‘NULL’
dereference and crash.  A similar argument works for fields of structs.

Another issue is that some struct fields are currently not hidden when
‘Py_LIMITED_API’ is defined, even though they’re part of the Limited
API.

For these reasons, we recommend testing an extension with 'all' minor
Python versions it supports, and preferably to build with the 'lowest'
such version.

We also recommend reviewing documentation of all used API to check if it
is explicitly part of the Limited API. Even with ‘Py_LIMITED_API’
defined, a few private declarations are exposed for technical reasons
(or even unintentionally, as bugs).

Also note that the Limited API is not necessarily stable: compiling with
‘Py_LIMITED_API’ with Python 3.8 means that the extension will run with
Python 3.12, but it will not necessarily 'compile' with Python 3.12.  In
particular, parts of the Limited API may be deprecated and removed,
provided that the Stable ABI stays stable.


File: python.info,  Node: Platform Considerations,  Next: Contents of Limited API,  Prev: Stable Application Binary Interface,  Up: C API Stability

7.2.3 Platform Considerations
-----------------------------

ABI stability depends not only on Python, but also on the compiler used,
lower-level libraries and compiler options.  For the purposes of the
*note Stable ABI: 4c1f, these details define a “platform”.  They usually
depend on the OS type and processor architecture

It is the responsibility of each particular distributor of Python to
ensure that all Python versions on a particular platform are built in a
way that does not break the Stable ABI. This is the case with Windows
and macOS releases from ‘python.org’ and many third-party distributors.


File: python.info,  Node: Contents of Limited API,  Prev: Platform Considerations,  Up: C API Stability

7.2.4 Contents of Limited API
-----------------------------

Currently, the *note Limited API: 399. includes the following items:

   * *note METH_CLASS: 1524.

   * *note METH_COEXIST: 14c6.

   * *note METH_FASTCALL: 1731.

   * *note METH_METHOD: 97a.

   * *note METH_NOARGS: 1523.

   * *note METH_O: 1557.

   * *note METH_STATIC: 1525.

   * *note METH_VARARGS: 1558.

   * *note PY_VECTORCALL_ARGUMENTS_OFFSET: 561.

   * *note PyAIter_Check(): 4c25.

   * *note PyArg_Parse(): 1b74.

   * *note PyArg_ParseTuple(): 574.

   * *note PyArg_ParseTupleAndKeywords(): 386.

   * *note PyArg_UnpackTuple(): 1556.

   * *note PyArg_VaParse(): 4c26.

   * *note PyArg_VaParseTupleAndKeywords(): 387.

   * *note PyArg_ValidateKeywordArguments(): 4c27.

   * *note PyBUF_ANY_CONTIGUOUS: 4c28.

   * *note PyBUF_CONTIG: 4c29.

   * *note PyBUF_CONTIG_RO: 4c2a.

   * *note PyBUF_C_CONTIGUOUS: 1403.

   * *note PyBUF_FORMAT: 4c2b.

   * *note PyBUF_FULL: 4c2c.

   * *note PyBUF_FULL_RO: 4c2d.

   * *note PyBUF_F_CONTIGUOUS: 1404.

   * *note PyBUF_INDIRECT: 4c2e.

   * *note PyBUF_MAX_NDIM: 4c2f.

   * *note PyBUF_ND: 4c30.

   * *note PyBUF_READ: 17a3.

   * *note PyBUF_RECORDS: 4c31.

   * *note PyBUF_RECORDS_RO: 4c32.

   * *note PyBUF_SIMPLE: 4c33.

   * *note PyBUF_STRIDED: 4c34.

   * *note PyBUF_STRIDED_RO: 4c35.

   * *note PyBUF_STRIDES: 4c36.

   * *note PyBUF_WRITABLE: 1402.

   * *note PyBUF_WRITE: 17a4.

   * *note PyBaseObject_Type: 4c37.

   * *note PyBool_FromLong(): 4c38.

   * *note PyBool_Type: 4c39.

   * *note PyBuffer_FillContiguousStrides(): 762.

   * *note PyBuffer_FillInfo(): 763.

   * *note PyBuffer_FromContiguous(): 75f.

   * *note PyBuffer_GetPointer(): 75c.

   * *note PyBuffer_IsContiguous(): 761.

   * *note PyBuffer_Release(): 39d.

   * *note PyBuffer_SizeFromFormat(): 75d.

   * *note PyBuffer_ToContiguous(): 75e.

   * *note PyByteArrayIter_Type: 4c3a.

   * *note PyByteArray_AsString(): 4c3b.

   * *note PyByteArray_Concat(): 4c3c.

   * *note PyByteArray_FromObject(): 13f5.

   * *note PyByteArray_FromStringAndSize(): 13f6.

   * *note PyByteArray_Resize(): 4c3d.

   * *note PyByteArray_Size(): 4c3e.

   * *note PyByteArray_Type: 4c3f.

   * *note PyBytesIter_Type: 4c40.

   * *note PyBytes_AsString(): 88e.

   * *note PyBytes_AsStringAndSize(): 4c41.

   * *note PyBytes_Concat(): 4c42.

   * *note PyBytes_ConcatAndDel(): 4c43.

   * *note PyBytes_DecodeEscape(): 4c44.

   * *note PyBytes_FromFormat(): 1bba.

   * *note PyBytes_FromFormatV(): 4c45.

   * *note PyBytes_FromObject(): 4c46.

   * *note PyBytes_FromString(): 4c47.

   * *note PyBytes_FromStringAndSize(): 13ed.

   * *note PyBytes_Repr(): 4c48.

   * *note PyBytes_Size(): 4c49.

   * *note PyBytes_Type: 4c4a.

   * *note PyCFunction: 14c7.

   * *note PyCFunctionFast: 4c4b.

   * *note PyCFunctionFastWithKeywords: 4c4c.

   * *note PyCFunctionWithKeywords: 4c4d.

   * *note PyCFunction_GetFlags(): 4c4e.

   * *note PyCFunction_GetFunction(): 4c4f.

   * *note PyCFunction_GetSelf(): 4c50.

   * *note PyCFunction_New(): 1a57.

   * *note PyCFunction_NewEx(): 1b1f.

   * *note PyCFunction_Type: 4c51.

   * *note PyCMethod_New(): 1a51.

   * *note PyCallIter_New(): 4c52.

   * *note PyCallIter_Type: 4c53.

   * *note PyCallable_Check(): 4c54.

   * *note PyCapsule_Destructor: 4c55.

   * *note PyCapsule_GetContext(): 4c56.

   * *note PyCapsule_GetDestructor(): 4c57.

   * *note PyCapsule_GetName(): 4c58.

   * *note PyCapsule_GetPointer(): 4c59.

   * *note PyCapsule_Import(): 19b4.

   * *note PyCapsule_IsValid(): 13a9.

   * *note PyCapsule_New(): 4b8e.

   * *note PyCapsule_SetContext(): 4c5a.

   * *note PyCapsule_SetDestructor(): 4c5b.

   * *note PyCapsule_SetName(): 4c5c.

   * *note PyCapsule_SetPointer(): 4c5d.

   * *note PyCapsule_Type: 4c5e.

   * *note PyClassMethodDescr_Type: 4c5f.

   * *note PyCodec_BackslashReplaceErrors(): 4c60.

   * *note PyCodec_Decode(): 402.

   * *note PyCodec_Decoder(): 4c61.

   * *note PyCodec_Encode(): 403.

   * *note PyCodec_Encoder(): 4c62.

   * *note PyCodec_IgnoreErrors(): 4c63.

   * *note PyCodec_IncrementalDecoder(): 4c64.

   * *note PyCodec_IncrementalEncoder(): 4c65.

   * *note PyCodec_KnownEncoding(): 4c66.

   * *note PyCodec_LookupError(): 4c67.

   * *note PyCodec_NameReplaceErrors(): ee3.

   * *note PyCodec_Register(): 4c68.

   * *note PyCodec_RegisterError(): 4c69.

   * *note PyCodec_ReplaceErrors(): 4c6a.

   * *note PyCodec_StreamReader(): 4c6b.

   * *note PyCodec_StreamWriter(): 4c6c.

   * *note PyCodec_StrictErrors(): 4c6d.

   * *note PyCodec_Unregister(): 89e.

   * *note PyCodec_XMLCharRefReplaceErrors(): 4c6e.

   * *note PyComplex_FromDoubles(): 4c6f.

   * *note PyComplex_ImagAsDouble(): 17ab.

   * *note PyComplex_RealAsDouble(): 17aa.

   * *note PyComplex_Type: 4c70.

   * *note PyDescr_NewClassMethod(): 4c71.

   * *note PyDescr_NewGetSet(): 4c72.

   * *note PyDescr_NewMember(): 4c73.

   * *note PyDescr_NewMethod(): 1b1e.

   * *note PyDictItems_Type: 4c74.

   * *note PyDictIterItem_Type: 4c75.

   * *note PyDictIterKey_Type: 4c76.

   * *note PyDictIterValue_Type: 4c77.

   * *note PyDictKeys_Type: 4c78.

   * *note PyDictProxy_New(): 4c79.

   * *note PyDictProxy_Type: 4c7a.

   * *note PyDictRevIterItem_Type: 4c7b.

   * *note PyDictRevIterKey_Type: 4c7c.

   * *note PyDictRevIterValue_Type: 4c7d.

   * *note PyDictValues_Type: 4c7e.

   * *note PyDict_Clear(): 4c7f.

   * *note PyDict_Contains(): 339.

   * *note PyDict_Copy(): 423.

   * *note PyDict_DelItem(): 4c80.

   * *note PyDict_DelItemString(): 4c81.

   * *note PyDict_GetItem(): 38a.

   * *note PyDict_GetItemRef(): 33b.

   * *note PyDict_GetItemString(): 38b.

   * *note PyDict_GetItemStringRef(): 33c.

   * *note PyDict_GetItemWithError(): 33d.

   * *note PyDict_Items(): 4c82.

   * *note PyDict_Keys(): 4c83.

   * *note PyDict_Merge(): 4c84.

   * *note PyDict_MergeFromSeq2(): 4c85.

   * *note PyDict_New(): 4c86.

   * *note PyDict_Next(): 171b.

   * *note PyDict_SetItem(): 4b84.

   * *note PyDict_SetItemString(): 1709.

   * *note PyDict_Size(): 4c87.

   * *note PyDict_Type: 4c88.

   * *note PyDict_Update(): 4c89.

   * *note PyDict_Values(): 4c8a.

   * *note PyEllipsis_Type: 4c8b.

   * *note PyEnum_Type: 4c8c.

   * *note PyErr_BadArgument(): 4c8d.

   * *note PyErr_BadInternalCall(): 4c8e.

   * *note PyErr_CheckSignals(): 46a.

   * *note PyErr_Clear(): 106e.

   * ‘PyErr_Display()’

   * *note PyErr_DisplayException(): 405.

   * *note PyErr_ExceptionMatches(): 4c10.

   * *note PyErr_Fetch(): 3f6.

   * *note PyErr_Format(): ee5.

   * *note PyErr_FormatV(): ee4.

   * *note PyErr_GetExcInfo(): 775.

   * *note PyErr_GetHandledException(): 772.

   * *note PyErr_GetRaisedException(): 3f7.

   * *note PyErr_GivenExceptionMatches(): 4c8f.

   * *note PyErr_NewException(): 12b0.

   * *note PyErr_NewExceptionWithDoc(): 12af.

   * *note PyErr_NoMemory(): 4b63.

   * *note PyErr_NormalizeException(): 3f8.

   * *note PyErr_Occurred(): 1a55.

   * *note PyErr_Print(): 1ad3.

   * *note PyErr_PrintEx(): 4c90.

   * *note PyErr_ProgramText(): 4c91.

   * *note PyErr_ResourceWarning(): d3f.

   * *note PyErr_Restore(): 3f9.

   * *note PyErr_SetExcFromWindowsErr(): 4c92.

   * *note PyErr_SetExcFromWindowsErrWithFilename(): 1825.

   * *note PyErr_SetExcFromWindowsErrWithFilenameObject(): 4c93.

   * *note PyErr_SetExcFromWindowsErrWithFilenameObjects(): 4c94.

   * *note PyErr_SetExcInfo(): 774.

   * *note PyErr_SetFromErrno(): 4b62.

   * *note PyErr_SetFromErrnoWithFilename(): 1824.

   * *note PyErr_SetFromErrnoWithFilenameObject(): 4c95.

   * *note PyErr_SetFromErrnoWithFilenameObjects(): 4c96.

   * *note PyErr_SetFromWindowsErr(): 4c97.

   * *note PyErr_SetFromWindowsErrWithFilename(): 1826.

   * *note PyErr_SetHandledException(): 773.

   * *note PyErr_SetImportError(): d66.

   * *note PyErr_SetImportErrorSubclass(): d3e.

   * *note PyErr_SetInterrupt(): 4c98.

   * *note PyErr_SetInterruptEx(): 8a5.

   * *note PyErr_SetNone(): 4c99.

   * *note PyErr_SetObject(): 57e.

   * *note PyErr_SetRaisedException(): 3fa.

   * *note PyErr_SetString(): 57f.

   * *note PyErr_SyntaxLocation(): 4c9a.

   * *note PyErr_SyntaxLocationEx(): 4c9b.

   * *note PyErr_WarnEx(): 149b.

   * *note PyErr_WarnExplicit(): 182c.

   * *note PyErr_WarnFormat(): 4c9c.

   * *note PyErr_WriteUnraisable(): 350.

   * *note PyEval_AcquireThread(): 3ad.

   * *note PyEval_EvalCode(): 88d.

   * *note PyEval_EvalCodeEx(): 187d.

   * *note PyEval_EvalFrame(): 4c9d.

   * *note PyEval_EvalFrameEx(): 106b.

   * *note PyEval_GetBuiltins(): 352.

   * *note PyEval_GetFrame(): 18dc.

   * *note PyEval_GetFrameBuiltins(): 351.

   * *note PyEval_GetFrameGlobals(): 353.

   * *note PyEval_GetFrameLocals(): 355.

   * *note PyEval_GetFuncDesc(): 4c9e.

   * *note PyEval_GetFuncName(): 4c9f.

   * *note PyEval_GetGlobals(): 354.

   * *note PyEval_GetLocals(): 356.

   * *note PyEval_InitThreads(): 174c.

   * *note PyEval_ReleaseThread(): 4ca0.

   * *note PyEval_RestoreThread(): 3ac.

   * *note PyEval_SaveThread(): 3ab.

   * *note PyExc_ArithmeticError: 4ca1.

   * *note PyExc_AssertionError: 4ca2.

   * *note PyExc_AttributeError: 4ca3.

   * *note PyExc_BaseException: 4ca4.

   * *note PyExc_BaseExceptionGroup: 4ca5.

   * *note PyExc_BlockingIOError: 4ca6.

   * *note PyExc_BrokenPipeError: 4ca7.

   * *note PyExc_BufferError: 4ca8.

   * *note PyExc_BytesWarning: 4ca9.

   * *note PyExc_ChildProcessError: 4caa.

   * *note PyExc_ConnectionAbortedError: 4cab.

   * *note PyExc_ConnectionError: 4cac.

   * *note PyExc_ConnectionRefusedError: 4cad.

   * *note PyExc_ConnectionResetError: 4cae.

   * *note PyExc_DeprecationWarning: 4caf.

   * *note PyExc_EOFError: 4cb0.

   * *note PyExc_EncodingWarning: 4cb1.

   * *note PyExc_EnvironmentError: 4cb2.

   * *note PyExc_Exception: 4cb3.

   * *note PyExc_FileExistsError: 4cb4.

   * *note PyExc_FileNotFoundError: 4cb5.

   * *note PyExc_FloatingPointError: 4cb6.

   * *note PyExc_FutureWarning: 4cb7.

   * *note PyExc_GeneratorExit: 4cb8.

   * *note PyExc_IOError: 4cb9.

   * *note PyExc_ImportError: 4cba.

   * *note PyExc_ImportWarning: 4cbb.

   * *note PyExc_IndentationError: 4cbc.

   * *note PyExc_IndexError: 4cbd.

   * *note PyExc_InterruptedError: 4cbe.

   * *note PyExc_IsADirectoryError: 4cbf.

   * *note PyExc_KeyError: 4cc0.

   * *note PyExc_KeyboardInterrupt: 4cc1.

   * *note PyExc_LookupError: 4cc2.

   * *note PyExc_MemoryError: 4cc3.

   * *note PyExc_ModuleNotFoundError: 4cc4.

   * *note PyExc_NameError: 4cc5.

   * *note PyExc_NotADirectoryError: 4cc6.

   * *note PyExc_NotImplementedError: 4cc7.

   * *note PyExc_OSError: 4b65.

   * *note PyExc_OverflowError: 4cc8.

   * *note PyExc_PendingDeprecationWarning: 4cc9.

   * *note PyExc_PermissionError: 4cca.

   * *note PyExc_ProcessLookupError: 4ccb.

   * *note PyExc_RecursionError: ee6.

   * *note PyExc_ReferenceError: 4ccc.

   * *note PyExc_ResourceWarning: 4ccd.

   * *note PyExc_RuntimeError: 4cce.

   * *note PyExc_RuntimeWarning: 4ccf.

   * *note PyExc_StopAsyncIteration: 4cd0.

   * *note PyExc_StopIteration: 4cd1.

   * *note PyExc_SyntaxError: 4cd2.

   * *note PyExc_SyntaxWarning: 4cd3.

   * *note PyExc_SystemError: 4cd4.

   * *note PyExc_SystemExit: 4cd5.

   * *note PyExc_TabError: 4cd6.

   * *note PyExc_TimeoutError: 4cd7.

   * *note PyExc_TypeError: 4b64.

   * *note PyExc_UnboundLocalError: 4cd8.

   * *note PyExc_UnicodeDecodeError: 4cd9.

   * *note PyExc_UnicodeEncodeError: 4cda.

   * *note PyExc_UnicodeError: 4cdb.

   * *note PyExc_UnicodeTranslateError: 4cdc.

   * *note PyExc_UnicodeWarning: 4cdd.

   * *note PyExc_UserWarning: 4cde.

   * *note PyExc_ValueError: 4b66.

   * *note PyExc_Warning: 4cdf.

   * *note PyExc_WindowsError: 4ce0.

   * *note PyExc_ZeroDivisionError: 4b61.

   * *note PyExceptionClass_Name(): a74.

   * *note PyException_GetArgs(): 56d.

   * *note PyException_GetCause(): 4ce1.

   * *note PyException_GetContext(): 4ce2.

   * *note PyException_GetTraceback(): 4ce3.

   * *note PyException_SetArgs(): 56e.

   * *note PyException_SetCause(): 4ce4.

   * *note PyException_SetContext(): 4ce5.

   * *note PyException_SetTraceback(): 1b7a.

   * *note PyFile_FromFd(): 4ce6.

   * *note PyFile_GetLine(): 4ce7.

   * *note PyFile_WriteObject(): 4ce8.

   * *note PyFile_WriteString(): 4ce9.

   * *note PyFilter_Type: 4cea.

   * *note PyFloat_AsDouble(): a78.

   * *note PyFloat_FromDouble(): 4ceb.

   * *note PyFloat_FromString(): 4cec.

   * *note PyFloat_GetInfo(): 143e.

   * *note PyFloat_GetMax(): 143c.

   * *note PyFloat_GetMin(): 143d.

   * *note PyFloat_Type: 4ced.

   * *note PyFrameObject: 78c.

   * *note PyFrame_GetCode(): 78d.

   * *note PyFrame_GetLineNumber(): 78e.

   * *note PyFrozenSet_New(): 1494.

   * *note PyFrozenSet_Type: 4cee.

   * *note PyGC_Collect(): 998.

   * *note PyGC_Disable(): 8ac.

   * *note PyGC_Enable(): 8ab.

   * *note PyGC_IsEnabled(): 8ad.

   * *note PyGILState_Ensure(): 3ae.

   * *note PyGILState_GetThisThreadState(): 4cef.

   * *note PyGILState_Release(): 3af.

   * *note PyGILState_STATE: 4cf0.

   * *note PyGetSetDef: bd7.

   * *note PyGetSetDescr_Type: 4cf1.

   * *note PyImport_AddModule(): 35a.

   * *note PyImport_AddModuleObject(): 4cf2.

   * *note PyImport_AddModuleRef(): 359.

   * *note PyImport_AppendInittab(): 18bf.

   * *note PyImport_ExecCodeModule(): 4cf3.

   * *note PyImport_ExecCodeModuleEx(): 4cf4.

   * *note PyImport_ExecCodeModuleObject(): 4cf5.

   * *note PyImport_ExecCodeModuleWithPathnames(): 4cf6.

   * *note PyImport_GetImporter(): 1823.

   * *note PyImport_GetMagicNumber(): 11e7.

   * *note PyImport_GetMagicTag(): 4cf7.

   * *note PyImport_GetModule(): bd1.

   * *note PyImport_GetModuleDict(): 4cf8.

   * *note PyImport_Import(): 144a.

   * *note PyImport_ImportFrozenModule(): 4cf9.

   * *note PyImport_ImportFrozenModuleObject(): 4cfa.

   * *note PyImport_ImportModule(): 3c1.

   * *note PyImport_ImportModuleLevel(): 11e8.

   * *note PyImport_ImportModuleLevelObject(): 4cfb.

   * *note PyImport_ImportModuleNoBlock(): 3c0.

   * *note PyImport_ReloadModule(): 4cfc.

   * *note PyIndex_Check(): 994.

   * *note PyInterpreterState: 8c5.

   * *note PyInterpreterState_Clear(): 4421.

   * *note PyInterpreterState_Delete(): 4cfd.

   * *note PyInterpreterState_Get(): 3b0.

   * *note PyInterpreterState_GetDict(): 4cfe.

   * *note PyInterpreterState_GetID(): be5.

   * *note PyInterpreterState_New(): 4422.

   * *note PyIter_Check(): 1a58.

   * *note PyIter_Next(): 4cff.

   * *note PyIter_Send(): 89f.

   * *note PyListIter_Type: 4d00.

   * *note PyListRevIter_Type: 4d01.

   * *note PyList_Append(): 4d02.

   * *note PyList_AsTuple(): 4d03.

   * *note PyList_GetItem(): 35d.

   * *note PyList_GetItemRef(): 35c.

   * *note PyList_GetSlice(): 4d04.

   * *note PyList_Insert(): 167c.

   * *note PyList_New(): 4c0b.

   * *note PyList_Reverse(): 4d05.

   * *note PyList_SetItem(): 167d.

   * *note PyList_SetSlice(): 4d06.

   * *note PyList_Size(): 1468.

   * *note PyList_Sort(): 4d07.

   * *note PyList_Type: 4ba5.

   * *note PyLongObject: 58b.

   * *note PyLongRangeIter_Type: 4d08.

   * *note PyLong_AsDouble(): 4d09.

   * *note PyLong_AsInt(): 362.

   * *note PyLong_AsLong(): 363.

   * *note PyLong_AsLongAndOverflow(): 12ad.

   * *note PyLong_AsLongLong(): 4d0a.

   * *note PyLong_AsLongLongAndOverflow(): 12ac.

   * *note PyLong_AsSize_t(): 4d0b.

   * *note PyLong_AsSsize_t(): 4d0c.

   * *note PyLong_AsUnsignedLong(): 4d0d.

   * *note PyLong_AsUnsignedLongLong(): 12db.

   * *note PyLong_AsUnsignedLongLongMask(): 1b76.

   * *note PyLong_AsUnsignedLongMask(): 4d0e.

   * *note PyLong_AsVoidPtr(): 4d0f.

   * *note PyLong_FromDouble(): 94c.

   * *note PyLong_FromLong(): 1975.

   * *note PyLong_FromLongLong(): 1976.

   * *note PyLong_FromSize_t(): 1b53.

   * *note PyLong_FromSsize_t(): 4d10.

   * *note PyLong_FromString(): 4d11.

   * *note PyLong_FromUnsignedLong(): 1b51.

   * *note PyLong_FromUnsignedLongLong(): 1b52.

   * *note PyLong_FromVoidPtr(): 4d12.

   * *note PyLong_GetInfo(): 4d13.

   * *note PyLong_Type: 4d14.

   * *note PyMap_Type: 4d15.

   * *note PyMapping_Check(): 4d16.

   * *note PyMapping_GetItemString(): 349.

   * *note PyMapping_GetOptionalItem(): 346.

   * *note PyMapping_GetOptionalItemString(): 347.

   * *note PyMapping_HasKey(): 382.

   * *note PyMapping_HasKeyString(): 384.

   * *note PyMapping_HasKeyStringWithError(): 383.

   * *note PyMapping_HasKeyWithError(): 381.

   * *note PyMapping_Items(): bdd.

   * *note PyMapping_Keys(): bdb.

   * *note PyMapping_Length(): 4d17.

   * *note PyMapping_SetItemString(): 4d18.

   * *note PyMapping_Size(): 1be8.

   * *note PyMapping_Values(): bdc.

   * *note PyMem_Calloc(): ee1.

   * *note PyMem_Free(): 1491.

   * *note PyMem_Malloc(): c87.

   * *note PyMem_RawCalloc(): 394.

   * *note PyMem_RawFree(): 396.

   * *note PyMem_RawMalloc(): 393.

   * *note PyMem_RawRealloc(): 395.

   * *note PyMem_Realloc(): 106f.

   * *note PyMemberDef: 552.

   * *note PyMemberDescr_Type: 4d19.

   * *note PyMember_GetOne(): 590.

   * *note PyMember_SetOne(): 591.

   * *note PyMemoryView_FromBuffer(): 764.

   * *note PyMemoryView_FromMemory(): 11b4.

   * *note PyMemoryView_FromObject(): 4d1a.

   * *note PyMemoryView_GetContiguous(): 4d1b.

   * *note PyMemoryView_Type: 4d1c.

   * *note PyMethodDef: 1526.

   * *note PyMethodDescr_Type: 4d1d.

   * *note PyModuleDef: 987.

   * ‘PyModuleDef_Base’

   * *note PyModuleDef_Init(): 4b6d.

   * *note PyModuleDef_Slot: 4d1e.

   * *note PyModuleDef_Type: 4d1f.

   * *note PyModule_Add(): 367.

   * *note PyModule_AddFunctions(): 4d20.

   * *note PyModule_AddIntConstant(): 158c.

   * *note PyModule_AddObject(): 369.

   * *note PyModule_AddObjectRef(): 368.

   * *note PyModule_AddStringConstant(): 158d.

   * *note PyModule_AddType(): 97f.

   * *note PyModule_Create2(): 4d21.

   * *note PyModule_ExecDef(): ee9.

   * *note PyModule_FromDefAndSpec2(): ee8.

   * *note PyModule_GetDef(): 4d22.

   * *note PyModule_GetDict(): 4d23.

   * *note PyModule_GetFilename(): 3fb.

   * *note PyModule_GetFilenameObject(): 3fc.

   * *note PyModule_GetName(): 4d24.

   * *note PyModule_GetNameObject(): 4d25.

   * *note PyModule_GetState(): 98a.

   * *note PyModule_New(): 4d26.

   * *note PyModule_NewObject(): 4d27.

   * *note PyModule_SetDocString(): 4d28.

   * *note PyModule_Type: 4d29.

   * *note PyNumber_Absolute(): 4d2a.

   * *note PyNumber_Add(): 4d2b.

   * *note PyNumber_And(): 4d2c.

   * *note PyNumber_AsSsize_t(): 4d2d.

   * *note PyNumber_Check(): a75.

   * *note PyNumber_Divmod(): 4d2e.

   * *note PyNumber_Float(): a77.

   * *note PyNumber_FloorDivide(): 4d2f.

   * *note PyNumber_InPlaceAdd(): 4d30.

   * *note PyNumber_InPlaceAnd(): 4d31.

   * *note PyNumber_InPlaceFloorDivide(): 4d32.

   * *note PyNumber_InPlaceLshift(): 4d33.

   * *note PyNumber_InPlaceMatrixMultiply(): eeb.

   * *note PyNumber_InPlaceMultiply(): 4d34.

   * *note PyNumber_InPlaceOr(): 4d35.

   * *note PyNumber_InPlacePower(): 4d36.

   * *note PyNumber_InPlaceRemainder(): 4d37.

   * *note PyNumber_InPlaceRshift(): 4d38.

   * *note PyNumber_InPlaceSubtract(): 4d39.

   * *note PyNumber_InPlaceTrueDivide(): 4d3a.

   * *note PyNumber_InPlaceXor(): 4d3b.

   * *note PyNumber_Index(): 89a.

   * *note PyNumber_Invert(): 4d3c.

   * *note PyNumber_Long(): a76.

   * *note PyNumber_Lshift(): 4d3d.

   * *note PyNumber_MatrixMultiply(): eea.

   * *note PyNumber_Multiply(): 4d3e.

   * *note PyNumber_Negative(): 4d3f.

   * *note PyNumber_Or(): 4d40.

   * *note PyNumber_Positive(): 4d41.

   * *note PyNumber_Power(): 4d42.

   * *note PyNumber_Remainder(): 4d43.

   * *note PyNumber_Rshift(): 4d44.

   * *note PyNumber_Subtract(): 4d45.

   * *note PyNumber_ToBase(): 1919.

   * *note PyNumber_TrueDivide(): 4d46.

   * *note PyNumber_Xor(): 4d47.

   * *note PyOS_AfterFork(): 3fd.

   * *note PyOS_AfterFork_Child(): 3fe.

   * *note PyOS_AfterFork_Parent(): bdf.

   * *note PyOS_BeforeFork(): bde.

   * *note PyOS_CheckStack(): 1947.

   * *note PyOS_FSPath(): d40.

   * *note PyOS_InputHook: 588.

   * *note PyOS_InterruptOccurred(): 1ae9.

   * *note PyOS_double_to_string(): 4d48.

   * *note PyOS_getsig(): 158e.

   * *note PyOS_mystricmp(): 1ae2.

   * *note PyOS_mystrnicmp(): 1ae1.

   * *note PyOS_setsig(): 158f.

   * *note PyOS_sighandler_t: 4d49.

   * *note PyOS_snprintf(): 1559.

   * *note PyOS_string_to_double(): 12dc.

   * *note PyOS_strtol(): 4d4a.

   * *note PyOS_strtoul(): 4d4b.

   * *note PyOS_vsnprintf(): 155a.

   * *note PyObject: 33a.

   * *note PyObject.ob_refcnt: 8a6.

   * *note PyObject.ob_type: 4b98.

   * *note PyObject_ASCII(): 4d4c.

   * *note PyObject_AsFileDescriptor(): 4d4d.

   * *note PyObject_Bytes(): 4d4e.

   * *note PyObject_Call(): 39f.

   * *note PyObject_CallFunction(): 3a1.

   * *note PyObject_CallFunctionObjArgs(): 4d4f.

   * *note PyObject_CallMethod(): 3a2.

   * *note PyObject_CallMethodObjArgs(): 1b8d.

   * *note PyObject_CallNoArgs(): 39e.

   * *note PyObject_CallObject(): 4b77.

   * *note PyObject_Calloc(): ee2.

   * *note PyObject_CheckBuffer(): 39b.

   * *note PyObject_ClearWeakRefs(): 579.

   * *note PyObject_CopyData(): 760.

   * *note PyObject_DelAttr(): 163f.

   * *note PyObject_DelAttrString(): 1640.

   * *note PyObject_DelItem(): 4d50.

   * *note PyObject_DelItemString(): 4d51.

   * *note PyObject_Dir(): 4d52.

   * *note PyObject_Format(): 4d53.

   * *note PyObject_Free(): c86.

   * *note PyObject_GC_Del(): 1553.

   * *note PyObject_GC_IsFinalized(): 981.

   * *note PyObject_GC_IsTracked(): 980.

   * *note PyObject_GC_Track(): 1554.

   * *note PyObject_GC_UnTrack(): 1555.

   * *note PyObject_GenericGetAttr(): 4d54.

   * *note PyObject_GenericGetDict(): 1aac.

   * *note PyObject_GenericSetAttr(): 4d55.

   * *note PyObject_GenericSetDict(): 4d56.

   * *note PyObject_GetAIter(): 4d57.

   * *note PyObject_GetAttr(): 34c.

   * *note PyObject_GetAttrString(): 34d.

   * *note PyObject_GetBuffer(): 39c.

   * *note PyObject_GetItem(): 348.

   * *note PyObject_GetIter(): 4d58.

   * *note PyObject_GetOptionalAttr(): 34a.

   * *note PyObject_GetOptionalAttrString(): 34b.

   * *note PyObject_GetTypeData(): 54c.

   * *note PyObject_HasAttr(): 37e.

   * *note PyObject_HasAttrString(): 380.

   * *note PyObject_HasAttrStringWithError(): 37f.

   * *note PyObject_HasAttrWithError(): 37d.

   * *note PyObject_Hash(): 406.

   * *note PyObject_HashNotImplemented(): 1413.

   * *note PyObject_Init(): a79.

   * *note PyObject_InitVar(): 1ae7.

   * *note PyObject_IsInstance(): eda.

   * *note PyObject_IsSubclass(): edb.

   * *note PyObject_IsTrue(): 4d59.

   * *note PyObject_Length(): 4d5a.

   * *note PyObject_Malloc(): c89.

   * *note PyObject_Not(): 4d5b.

   * *note PyObject_Realloc(): 1492.

   * *note PyObject_Repr(): 106c.

   * *note PyObject_RichCompare(): 4bbb.

   * *note PyObject_RichCompareBool(): 1b35.

   * *note PyObject_SelfIter(): 4d5c.

   * *note PyObject_SetAttr(): 4d5d.

   * *note PyObject_SetAttrString(): 170a.

   * *note PyObject_SetItem(): 4c0a.

   * *note PyObject_Size(): 4d5e.

   * *note PyObject_Str(): 106d.

   * *note PyObject_Type(): 4d5f.

   * *note PyObject_Vectorcall(): 55f.

   * *note PyObject_VectorcallMethod(): 560.

   * *note PyProperty_Type: 4d60.

   * *note PyRangeIter_Type: 4d61.

   * *note PyRange_Type: 4d62.

   * *note PyReversed_Type: 4d63.

   * *note PySeqIter_New(): 4d64.

   * *note PySeqIter_Type: 4d65.

   * *note PySequence_Check(): 4d66.

   * *note PySequence_Concat(): 4d67.

   * *note PySequence_Contains(): 4d68.

   * *note PySequence_Count(): 4d69.

   * *note PySequence_DelItem(): 1be7.

   * *note PySequence_DelSlice(): 4d6a.

   * *note PySequence_Fast(): 4d6b.

   * *note PySequence_GetItem(): 1be5.

   * *note PySequence_GetSlice(): 4d6c.

   * ‘PySequence_In()’

   * *note PySequence_InPlaceConcat(): 4d6d.

   * *note PySequence_InPlaceRepeat(): 4d6e.

   * *note PySequence_Index(): 4d6f.

   * *note PySequence_Length(): 4d70.

   * *note PySequence_List(): 4d71.

   * *note PySequence_Repeat(): 4d72.

   * *note PySequence_SetItem(): 1be6.

   * *note PySequence_SetSlice(): 4d73.

   * *note PySequence_Size(): 1be4.

   * *note PySequence_Tuple(): 4d74.

   * *note PySetIter_Type: 4d75.

   * *note PySet_Add(): 1495.

   * *note PySet_Clear(): 4d76.

   * *note PySet_Contains(): 1497.

   * *note PySet_Discard(): 1496.

   * *note PySet_New(): 1493.

   * *note PySet_Pop(): 4d77.

   * *note PySet_Size(): 1498.

   * *note PySet_Type: 4d78.

   * *note PySlice_AdjustIndices(): 401.

   * *note PySlice_GetIndices(): 4d79.

   * *note PySlice_GetIndicesEx(): 3ff.

   * *note PySlice_New(): 4d7a.

   * *note PySlice_Type: 4d7b.

   * *note PySlice_Unpack(): 400.

   * *note PyState_AddModule(): 4d7c.

   * *note PyState_FindModule(): 4d7d.

   * *note PyState_RemoveModule(): 4d7e.

   * *note PyStructSequence_Desc: bd9.

   * *note PyStructSequence_Field: bd8.

   * *note PyStructSequence_GetItem(): 4d7f.

   * *note PyStructSequence_New(): 4d80.

   * *note PyStructSequence_NewType(): 4d81.

   * *note PyStructSequence_SetItem(): 4d82.

   * *note PyStructSequence_UnnamedField: 98c.

   * *note PySuper_Type: 4d83.

   * *note PySys_Audit(): 372.

   * *note PySys_AuditTuple(): 371.

   * *note PySys_FormatStderr(): 4d84.

   * *note PySys_FormatStdout(): 4d85.

   * *note PySys_GetObject(): 38c.

   * *note PySys_GetXOptions(): 4d86.

   * *note PySys_ResetWarnOptions(): 3b2.

   * *note PySys_SetArgv(): 174b.

   * *note PySys_SetArgvEx(): 174a.

   * *note PySys_SetObject(): 4d87.

   * *note PySys_WriteStderr(): 4d88.

   * *note PySys_WriteStdout(): 4d89.

   * *note PyThreadState: 790.

   * *note PyThreadState_Clear(): 1729.

   * *note PyThreadState_Delete(): 1b32.

   * *note PyThreadState_Get(): 375.

   * *note PyThreadState_GetDict(): 4d8a.

   * *note PyThreadState_GetFrame(): 791.

   * *note PyThreadState_GetID(): 97c.

   * *note PyThreadState_GetInterpreter(): 97b.

   * *note PyThreadState_New(): 4d8b.

   * *note PyThreadState_SetAsyncExc(): be3.

   * *note PyThreadState_Swap(): 4d8c.

   * *note PyThread_GetInfo(): 4d8d.

   * *note PyThread_ReInitTLS(): 411.

   * *note PyThread_acquire_lock(): 4d8e.

   * *note PyThread_acquire_lock_timed(): 4d8f.

   * *note PyThread_allocate_lock(): 4d90.

   * *note PyThread_create_key(): 407.

   * *note PyThread_delete_key(): 409.

   * *note PyThread_delete_key_value(): 40f.

   * *note PyThread_exit_thread(): 4d91.

   * *note PyThread_free_lock(): 4d92.

   * *note PyThread_get_key_value(): 40d.

   * *note PyThread_get_stacksize(): 4d93.

   * *note PyThread_get_thread_ident(): 4d94.

   * *note PyThread_get_thread_native_id(): 1948.

   * *note PyThread_init_thread(): 4d95.

   * *note PyThread_release_lock(): 4d96.

   * *note PyThread_set_key_value(): 40b.

   * *note PyThread_set_stacksize(): 4d97.

   * *note PyThread_start_new_thread(): 1bdc.

   * *note PyThread_tss_alloc(): 408.

   * *note PyThread_tss_create(): 4d98.

   * *note PyThread_tss_delete(): 410.

   * *note PyThread_tss_free(): 40a.

   * *note PyThread_tss_get(): 40e.

   * *note PyThread_tss_is_created(): 4d99.

   * *note PyThread_tss_set(): 40c.

   * *note PyTraceBack_Here(): 4d9a.

   * *note PyTraceBack_Print(): 4d9b.

   * *note PyTraceBack_Type: 4d9c.

   * *note PyTupleIter_Type: 4d9d.

   * *note PyTuple_GetItem(): 4b82.

   * *note PyTuple_GetSlice(): 4d9e.

   * *note PyTuple_New(): 3a0.

   * *note PyTuple_Pack(): 4d9f.

   * *note PyTuple_SetItem(): 4b83.

   * *note PyTuple_Size(): 4da0.

   * *note PyTuple_Type: 4da1.

   * *note PyTypeObject: aba.

   * *note PyType_ClearCache(): 4da2.

   * *note PyType_FromMetaclass(): 553.

   * *note PyType_FromModuleAndSpec(): 554.

   * *note PyType_FromSpec(): 580.

   * *note PyType_FromSpecWithBases(): 581.

   * *note PyType_GenericAlloc(): a7a.

   * *note PyType_GenericNew(): 4b97.

   * *note PyType_GetFlags(): 1ae4.

   * *note PyType_GetFullyQualifiedName(): 376.

   * *note PyType_GetModule(): 978.

   * *note PyType_GetModuleByDef(): 397.

   * *note PyType_GetModuleName(): 378.

   * *note PyType_GetModuleState(): 979.

   * *note PyType_GetName(): 755.

   * *note PyType_GetQualName(): 756.

   * *note PyType_GetSlot(): 8a3.

   * *note PyType_GetTypeDataSize(): 54d.

   * *note PyType_IsSubtype(): 4da3.

   * *note PyType_Modified(): 1921.

   * *note PyType_Ready(): 77f.

   * *note PyType_Slot: 4da4.

   * *note PyType_Spec: 1828.

   * *note PyType_Type: 550.

   * *note PyUnicodeDecodeError_Create(): 4da5.

   * *note PyUnicodeDecodeError_GetEncoding(): 4da6.

   * *note PyUnicodeDecodeError_GetEnd(): 4da7.

   * *note PyUnicodeDecodeError_GetObject(): 4da8.

   * *note PyUnicodeDecodeError_GetReason(): 4da9.

   * *note PyUnicodeDecodeError_GetStart(): 4daa.

   * *note PyUnicodeDecodeError_SetEnd(): 4dab.

   * *note PyUnicodeDecodeError_SetReason(): 4dac.

   * *note PyUnicodeDecodeError_SetStart(): 4dad.

   * *note PyUnicodeEncodeError_GetEncoding(): 4dae.

   * *note PyUnicodeEncodeError_GetEnd(): 4daf.

   * *note PyUnicodeEncodeError_GetObject(): 4db0.

   * *note PyUnicodeEncodeError_GetReason(): 4db1.

   * *note PyUnicodeEncodeError_GetStart(): 4db2.

   * *note PyUnicodeEncodeError_SetEnd(): 4db3.

   * *note PyUnicodeEncodeError_SetReason(): 4db4.

   * *note PyUnicodeEncodeError_SetStart(): 4db5.

   * *note PyUnicodeIter_Type: 4db6.

   * *note PyUnicodeTranslateError_GetEnd(): 4db7.

   * *note PyUnicodeTranslateError_GetObject(): 4db8.

   * *note PyUnicodeTranslateError_GetReason(): 4db9.

   * *note PyUnicodeTranslateError_GetStart(): 4dba.

   * *note PyUnicodeTranslateError_SetEnd(): 4dbb.

   * *note PyUnicodeTranslateError_SetReason(): 4dbc.

   * *note PyUnicodeTranslateError_SetStart(): 4dbd.

   * ‘PyUnicode_Append()’

   * ‘PyUnicode_AppendAndDel()’

   * *note PyUnicode_AsASCIIString(): 11d6.

   * *note PyUnicode_AsCharmapString(): 4dbe.

   * ‘PyUnicode_AsDecodedObject()’

   * ‘PyUnicode_AsDecodedUnicode()’

   * ‘PyUnicode_AsEncodedObject()’

   * *note PyUnicode_AsEncodedString(): 4dbf.

   * ‘PyUnicode_AsEncodedUnicode()’

   * *note PyUnicode_AsLatin1String(): 11d5.

   * *note PyUnicode_AsMBCSString(): 11d7.

   * *note PyUnicode_AsRawUnicodeEscapeString(): 11d4.

   * *note PyUnicode_AsUCS4(): 11bc.

   * *note PyUnicode_AsUCS4Copy(): 8c3.

   * *note PyUnicode_AsUTF16String(): 4dc0.

   * *note PyUnicode_AsUTF32String(): 4dc1.

   * *note PyUnicode_AsUTF8AndSize(): 8a0.

   * *note PyUnicode_AsUTF8String(): 11d2.

   * *note PyUnicode_AsUnicodeEscapeString(): 11d3.

   * *note PyUnicode_AsWideChar(): 1be9.

   * *note PyUnicode_AsWideCharString(): 8c4.

   * *note PyUnicode_BuildEncodingMap(): 1801.

   * *note PyUnicode_Compare(): 8bf.

   * *note PyUnicode_CompareWithASCIIString(): 12ae.

   * *note PyUnicode_Concat(): 11e5.

   * *note PyUnicode_Contains(): 4dc2.

   * *note PyUnicode_Count(): 4dc3.

   * *note PyUnicode_Decode(): 1b72.

   * *note PyUnicode_DecodeASCII(): 4dc4.

   * *note PyUnicode_DecodeCharmap(): 4dc5.

   * *note PyUnicode_DecodeCodePageStateful(): 4dc6.

   * *note PyUnicode_DecodeFSDefault(): 1827.

   * *note PyUnicode_DecodeFSDefaultAndSize(): 4dc7.

   * *note PyUnicode_DecodeLatin1(): 4dc8.

   * *note PyUnicode_DecodeLocale(): 4dc9.

   * *note PyUnicode_DecodeLocaleAndSize(): be8.

   * *note PyUnicode_DecodeMBCS(): 4dca.

   * *note PyUnicode_DecodeMBCSStateful(): 4dcb.

   * *note PyUnicode_DecodeRawUnicodeEscape(): 4dcc.

   * *note PyUnicode_DecodeUTF16(): 4dcd.

   * *note PyUnicode_DecodeUTF16Stateful(): 4dce.

   * *note PyUnicode_DecodeUTF32(): 4dcf.

   * *note PyUnicode_DecodeUTF32Stateful(): 4dd0.

   * *note PyUnicode_DecodeUTF7(): 4dd1.

   * *note PyUnicode_DecodeUTF7Stateful(): 4dd2.

   * *note PyUnicode_DecodeUTF8(): 4dd3.

   * *note PyUnicode_DecodeUTF8Stateful(): 18ba.

   * *note PyUnicode_DecodeUnicodeEscape(): 4dd4.

   * *note PyUnicode_EncodeCodePage(): 11d8.

   * *note PyUnicode_EncodeFSDefault(): 1be2.

   * *note PyUnicode_EncodeLocale(): be9.

   * *note PyUnicode_EqualToUTF8(): 37a.

   * *note PyUnicode_EqualToUTF8AndSize(): 379.

   * *note PyUnicode_FSConverter(): d41.

   * *note PyUnicode_FSDecoder(): 57a.

   * *note PyUnicode_Find(): 4dd5.

   * *note PyUnicode_FindChar(): 8c1.

   * *note PyUnicode_Format(): 4dd6.

   * *note PyUnicode_FromEncodedObject(): 4dd7.

   * *note PyUnicode_FromFormat(): 38d.

   * *note PyUnicode_FromFormatV(): 577.

   * *note PyUnicode_FromObject(): 4dd8.

   * *note PyUnicode_FromOrdinal(): 4dd9.

   * *note PyUnicode_FromString(): 4dda.

   * *note PyUnicode_FromStringAndSize(): 4ddb.

   * *note PyUnicode_FromWideChar(): 11d0.

   * *note PyUnicode_GetDefaultEncoding(): 4ddc.

   * *note PyUnicode_GetLength(): 8bb.

   * *note PyUnicode_InternFromString(): 1708.

   * *note PyUnicode_InternInPlace(): 8b9.

   * *note PyUnicode_IsIdentifier(): 1b2f.

   * *note PyUnicode_Join(): 11e6.

   * *note PyUnicode_Partition(): 1674.

   * *note PyUnicode_RPartition(): 1675.

   * *note PyUnicode_RSplit(): 1673.

   * *note PyUnicode_ReadChar(): 11b5.

   * *note PyUnicode_Replace(): 4ddd.

   * ‘PyUnicode_Resize()’

   * *note PyUnicode_RichCompare(): 4dde.

   * *note PyUnicode_Split(): 4ddf.

   * *note PyUnicode_Splitlines(): 4de0.

   * *note PyUnicode_Substring(): 8be.

   * *note PyUnicode_Tailmatch(): 8c0.

   * *note PyUnicode_Translate(): 4de1.

   * *note PyUnicode_Type: 4de2.

   * *note PyUnicode_WriteChar(): 11b6.

   * *note PyVarObject: 43a6.

   * ‘PyVarObject.ob_base’

   * *note PyVarObject.ob_size: 4de3.

   * *note PyVectorcall_Call(): 559.

   * *note PyVectorcall_NARGS(): 558.

   * ‘PyWeakReference’

   * *note PyWeakref_GetObject(): 37c.

   * *note PyWeakref_GetRef(): 37b.

   * *note PyWeakref_NewProxy(): 4de4.

   * *note PyWeakref_NewRef(): 198a.

   * *note PyWrapperDescr_Type: 4de5.

   * *note PyWrapper_New(): 4de6.

   * *note PyZip_Type: 4de7.

   * *note Py_AUDIT_READ: 595.

   * *note Py_AddPendingCall(): 98b.

   * *note Py_AtExit(): 4de8.

   * *note Py_BEGIN_ALLOW_THREADS: 4b88.

   * *note Py_BLOCK_THREADS: 4de9.

   * *note Py_BuildValue(): 8af.

   * *note Py_BytesMain(): 9cc.

   * *note Py_CompileString(): 88c.

   * *note Py_DecRef(): 4dea.

   * *note Py_DecodeLocale(): be6.

   * *note Py_END_ALLOW_THREADS: a9d.

   * *note Py_EncodeLocale(): be7.

   * *note Py_EndInterpreter(): 19a0.

   * *note Py_EnterRecursiveCall(): 97d.

   * *note Py_Exit(): d78.

   * *note Py_FatalError(): 98d.

   * ‘Py_FileSystemDefaultEncodeErrors’

   * ‘Py_FileSystemDefaultEncoding’

   * *note Py_Finalize(): 13a6.

   * *note Py_FinalizeEx(): d3d.

   * *note Py_GenericAlias(): 4deb.

   * *note Py_GenericAliasType: 4dec.

   * *note Py_GetBuildInfo(): 1480.

   * *note Py_GetCompiler(): 4ded.

   * *note Py_GetConstant(): 357.

   * *note Py_GetConstantBorrowed(): 358.

   * *note Py_GetCopyright(): 4dee.

   * *note Py_GetExecPrefix(): 3b4.

   * *note Py_GetPath(): 3b6.

   * *note Py_GetPlatform(): 4def.

   * *note Py_GetPrefix(): 3b8.

   * *note Py_GetProgramFullPath(): 3ba.

   * *note Py_GetProgramName(): 3bc.

   * *note Py_GetPythonHome(): 3bd.

   * *note Py_GetRecursionLimit(): 4df0.

   * *note Py_GetVersion(): 4df1.

   * ‘Py_HasFileSystemDefaultEncoding’

   * *note Py_IncRef(): 4df2.

   * *note Py_Initialize(): 8b4.

   * *note Py_InitializeEx(): 4df3.

   * *note Py_Is(): 8a7.

   * *note Py_IsFalse(): 8aa.

   * *note Py_IsFinalizing(): 35b.

   * *note Py_IsInitialized(): 4c13.

   * *note Py_IsNone(): 8a8.

   * *note Py_IsTrue(): 8a9.

   * *note Py_LeaveRecursiveCall(): 97e.

   * *note Py_Main(): c45.

   * *note Py_MakePendingCalls(): 4df4.

   * *note Py_NewInterpreter(): 18d4.

   * *note Py_NewRef(): 8a1.

   * *note Py_READONLY: 594.

   * *note Py_RELATIVE_OFFSET: 551.

   * *note Py_ReprEnter(): 4df5.

   * *note Py_ReprLeave(): 4df6.

   * *note Py_SetProgramName(): 1749.

   * *note Py_SetPythonHome(): 1748.

   * *note Py_SetRecursionLimit(): 4df7.

   * *note Py_TPFLAGS_BASETYPE: 4b9f.

   * *note Py_TPFLAGS_DEFAULT: 4b95.

   * *note Py_TPFLAGS_HAVE_GC: 780.

   * *note Py_TPFLAGS_HAVE_VECTORCALL: 557.

   * *note Py_TPFLAGS_ITEMS_AT_END: 54e.

   * *note Py_TPFLAGS_METHOD_DESCRIPTOR: 4df8.

   * *note Py_T_BOOL: 4df9.

   * *note Py_T_BYTE: 4dfa.

   * *note Py_T_CHAR: 4dfb.

   * *note Py_T_DOUBLE: 593.

   * *note Py_T_FLOAT: 4dfc.

   * *note Py_T_INT: 592.

   * *note Py_T_LONG: 4dfd.

   * *note Py_T_LONGLONG: 4dfe.

   * *note Py_T_OBJECT_EX: 597.

   * *note Py_T_PYSSIZET: 4dff.

   * *note Py_T_SHORT: 4e00.

   * *note Py_T_STRING: 4e01.

   * *note Py_T_STRING_INPLACE: 4e02.

   * *note Py_T_UBYTE: 4e03.

   * *note Py_T_UINT: 4e04.

   * *note Py_T_ULONG: 4e05.

   * *note Py_T_ULONGLONG: 4e06.

   * *note Py_T_USHORT: 4e07.

   * *note Py_UCS4: 29b.

   * *note Py_UNBLOCK_THREADS: 4e08.

   * ‘Py_UTF8Mode’

   * *note Py_VaBuildValue(): 4e09.

   * *note Py_Version: 759.

   * *note Py_XNewRef(): 8a2.

   * *note Py_am_aiter: 4e0a.

   * *note Py_am_anext: 4e0b.

   * *note Py_am_await: 4e0c.

   * *note Py_am_send: 4e0d.

   * *note Py_bf_getbuffer: 4e0e.

   * *note Py_bf_releasebuffer: 4e0f.

   * *note Py_buffer: 75b.

   * ‘Py_intptr_t’

   * *note Py_mod_create: 4e10.

   * *note Py_mod_exec: 988.

   * *note Py_mod_gil: 158.

   * *note Py_mod_multiple_interpreters: 4e11.

   * *note Py_mp_ass_subscript: 4e12.

   * *note Py_mp_length: 4e13.

   * *note Py_mp_subscript: 4e14.

   * *note Py_nb_absolute: 4e15.

   * *note Py_nb_add: 4e16.

   * *note Py_nb_and: 4e17.

   * *note Py_nb_bool: 4e18.

   * *note Py_nb_divmod: 4e19.

   * *note Py_nb_float: 4e1a.

   * *note Py_nb_floor_divide: 4e1b.

   * *note Py_nb_index: 4e1c.

   * *note Py_nb_inplace_add: 4e1d.

   * *note Py_nb_inplace_and: 4e1e.

   * *note Py_nb_inplace_floor_divide: 4e1f.

   * *note Py_nb_inplace_lshift: 4e20.

   * *note Py_nb_inplace_matrix_multiply: 4e21.

   * *note Py_nb_inplace_multiply: 4e22.

   * *note Py_nb_inplace_or: 4e23.

   * *note Py_nb_inplace_power: 4e24.

   * *note Py_nb_inplace_remainder: 4e25.

   * *note Py_nb_inplace_rshift: 4e26.

   * *note Py_nb_inplace_subtract: 4e27.

   * *note Py_nb_inplace_true_divide: 4e28.

   * *note Py_nb_inplace_xor: 4e29.

   * *note Py_nb_int: 4e2a.

   * *note Py_nb_invert: 4e2b.

   * *note Py_nb_lshift: 4e2c.

   * *note Py_nb_matrix_multiply: 4e2d.

   * *note Py_nb_multiply: 4e2e.

   * *note Py_nb_negative: 4e2f.

   * *note Py_nb_or: 4e30.

   * *note Py_nb_positive: 4e31.

   * *note Py_nb_power: 4e32.

   * *note Py_nb_remainder: 4e33.

   * *note Py_nb_rshift: 4e34.

   * *note Py_nb_subtract: 4e35.

   * *note Py_nb_true_divide: 4e36.

   * *note Py_nb_xor: 4e37.

   * *note Py_sq_ass_item: 4e38.

   * *note Py_sq_concat: 4e39.

   * *note Py_sq_contains: 4e3a.

   * *note Py_sq_inplace_concat: 4e3b.

   * *note Py_sq_inplace_repeat: 4e3c.

   * *note Py_sq_item: 4e3d.

   * *note Py_sq_length: 4e3e.

   * *note Py_sq_repeat: 4e3f.

   * *note Py_ssize_t: a6e.

   * *note Py_tp_alloc: 4e40.

   * *note Py_tp_base: 4e41.

   * *note Py_tp_bases: 4e42.

   * *note Py_tp_call: 4e43.

   * *note Py_tp_clear: 4e44.

   * *note Py_tp_dealloc: 4e45.

   * *note Py_tp_del: 4e46.

   * *note Py_tp_descr_get: 4e47.

   * *note Py_tp_descr_set: 4e48.

   * *note Py_tp_doc: 4e49.

   * *note Py_tp_finalize: 4e4a.

   * *note Py_tp_free: 4e4b.

   * *note Py_tp_getattr: 4e4c.

   * *note Py_tp_getattro: 4e4d.

   * *note Py_tp_getset: 4e4e.

   * *note Py_tp_hash: 4e4f.

   * *note Py_tp_init: 4e50.

   * *note Py_tp_is_gc: 4e51.

   * *note Py_tp_iter: 4e52.

   * *note Py_tp_iternext: 4e53.

   * *note Py_tp_members: 4e54.

   * *note Py_tp_methods: 4e55.

   * *note Py_tp_new: 4e56.

   * *note Py_tp_repr: 4e57.

   * *note Py_tp_richcompare: 4e58.

   * *note Py_tp_setattr: 4e59.

   * *note Py_tp_setattro: 4e5a.

   * *note Py_tp_str: 4e5b.

   * *note Py_tp_traverse: 4e5c.

   * ‘Py_uintptr_t’

   * *note allocfunc: 4e5d.

   * *note binaryfunc: 4e5e.

   * *note descrgetfunc: 4e5f.

   * *note descrsetfunc: 4e60.

   * *note destructor: 4e61.

   * *note getattrfunc: 4e62.

   * *note getattrofunc: 4e63.

   * *note getbufferproc: 4e64.

   * *note getiterfunc: 4e65.

   * *note getter: 4e66.

   * *note hashfunc: 4e67.

   * *note initproc: 4e68.

   * *note inquiry: 4e69.

   * *note iternextfunc: 4e6a.

   * *note lenfunc: 4e6b.

   * *note newfunc: 4e6c.

   * *note objobjargproc: 4e6d.

   * *note objobjproc: 4e6e.

   * *note releasebufferproc: 4e6f.

   * *note reprfunc: 4e70.

   * *note richcmpfunc: 4e71.

   * *note setattrfunc: 4e72.

   * *note setattrofunc: 4e73.

   * *note setter: 4e74.

   * *note ssizeargfunc: 4e75.

   * *note ssizeobjargproc: 4e76.

   * ‘ssizessizeargfunc’

   * ‘ssizessizeobjargproc’

   * ‘symtable’

   * *note ternaryfunc: 4e77.

   * *note traverseproc: 4e78.

   * *note unaryfunc: 4e79.

   * *note vectorcallfunc: 55a.

   * *note visitproc: 4e7a.


File: python.info,  Node: The Very High Level Layer,  Next: Reference Counting,  Prev: C API Stability,  Up: Python/C API Reference Manual

7.3 The Very High Level Layer
=============================

The functions in this chapter will let you execute Python source code
given in a file or a buffer, but they will not let you interact in a
more detailed way with the interpreter.

Several of these functions accept a start symbol from the grammar as a
parameter.  The available start symbols are *note Py_eval_input: 4e7f,
*note Py_file_input: 4e80, *note Py_single_input: 4e81, and *note
Py_func_type_input: 4e82.  These are described following the functions
which accept them as parameters.

Note also that several of these functions take FILE* parameters.  One
particular issue which needs to be handled carefully is that the ‘FILE’
structure for different C libraries can be different and incompatible.
Under Windows (at least), it is possible for dynamically linked
extensions to actually use different libraries, so care should be taken
that FILE* parameters are only passed to these functions if it is
certain that they were created by the same library that the Python
runtime is using.

 -- C Function: int PyRun_AnyFile (FILE *fp, const char *filename)

     This is a simplified interface to *note PyRun_AnyFileExFlags():
     4e84. below, leaving 'closeit' set to ‘0’ and 'flags' set to
     ‘NULL’.

 -- C Function: int PyRun_AnyFileFlags (FILE *fp, const char *filename,
          PyCompilerFlags *flags)

     This is a simplified interface to *note PyRun_AnyFileExFlags():
     4e84. below, leaving the 'closeit' argument set to ‘0’.

 -- C Function: int PyRun_AnyFileEx (FILE *fp, const char *filename, int
          closeit)

     This is a simplified interface to *note PyRun_AnyFileExFlags():
     4e84. below, leaving the 'flags' argument set to ‘NULL’.

 -- C Function: int PyRun_AnyFileExFlags (FILE *fp, const char
          *filename, int closeit, PyCompilerFlags *flags)

     If 'fp' refers to a file associated with an interactive device
     (console or terminal input or Unix pseudo-terminal), return the
     value of *note PyRun_InteractiveLoop(): 4e87, otherwise return the
     result of *note PyRun_SimpleFile(): 4bd7.  'filename' is decoded
     from the filesystem encoding (*note sys.getfilesystemencoding():
     c7a.).  If 'filename' is ‘NULL’, this function uses ‘"???"’ as the
     filename.  If 'closeit' is true, the file is closed before
     ‘PyRun_SimpleFileExFlags()’ returns.

 -- C Function: int PyRun_SimpleString (const char *command)

     This is a simplified interface to *note PyRun_SimpleStringFlags():
     4e88. below, leaving the *note PyCompilerFlags: ab6.* argument set
     to ‘NULL’.

 -- C Function: int PyRun_SimpleStringFlags (const char *command,
          PyCompilerFlags *flags)

     Executes the Python source code from 'command' in the *note
     __main__: 1. module according to the 'flags' argument.  If
     ‘__main__’ does not already exist, it is created.  Returns ‘0’ on
     success or ‘-1’ if an exception was raised.  If there was an error,
     there is no way to get the exception information.  For the meaning
     of 'flags', see below.

     Note that if an otherwise unhandled *note SystemExit: d69. is
     raised, this function will not return ‘-1’, but exit the process,
     as long as *note PyConfig.inspect: 3d2. is zero.

 -- C Function: int PyRun_SimpleFile (FILE *fp, const char *filename)

     This is a simplified interface to *note PyRun_SimpleFileExFlags():
     1a70. below, leaving 'closeit' set to ‘0’ and 'flags' set to
     ‘NULL’.

 -- C Function: int PyRun_SimpleFileEx (FILE *fp, const char *filename,
          int closeit)

     This is a simplified interface to *note PyRun_SimpleFileExFlags():
     1a70. below, leaving 'flags' set to ‘NULL’.

 -- C Function: int PyRun_SimpleFileExFlags (FILE *fp, const char
          *filename, int closeit, PyCompilerFlags *flags)

     Similar to *note PyRun_SimpleStringFlags(): 4e88, but the Python
     source code is read from 'fp' instead of an in-memory string.
     'filename' should be the name of the file, it is decoded from *note
     filesystem encoding and error handler: 53e.  If 'closeit' is true,
     the file is closed before ‘PyRun_SimpleFileExFlags()’ returns.

          Note: On Windows, 'fp' should be opened as binary mode (e.g.
          ‘fopen(filename, "rb")’).  Otherwise, Python may not handle
          script file with LF line ending correctly.

 -- C Function: int PyRun_InteractiveOneObject (FILE *fp, PyObject
          *filename, PyCompilerFlags *flags)

     Read and execute a single statement from a file associated with an
     interactive device according to the 'flags' argument.  The user
     will be prompted using ‘sys.ps1’ and ‘sys.ps2’.  'filename' must be
     a Python *note str: 44f. object.

     Returns ‘0’ when the input was executed successfully, ‘-1’ if there
     was an exception, or an error code from the ‘errcode.h’ include
     file distributed as part of Python if there was a parse error.
     (Note that ‘errcode.h’ is not included by ‘Python.h’, so must be
     included specifically if needed.)

 -- C Function: int PyRun_InteractiveOne (FILE *fp, const char
          *filename)

     This is a simplified interface to *note
     PyRun_InteractiveOneFlags(): 4e8c. below, leaving 'flags' set to
     ‘NULL’.

 -- C Function: int PyRun_InteractiveOneFlags (FILE *fp, const char
          *filename, PyCompilerFlags *flags)

     Similar to *note PyRun_InteractiveOneObject(): 4e8a, but 'filename'
     is a const char*, which is decoded from the *note filesystem
     encoding and error handler: 53e.

 -- C Function: int PyRun_InteractiveLoop (FILE *fp, const char
          *filename)

     This is a simplified interface to *note
     PyRun_InteractiveLoopFlags(): 4e8d. below, leaving 'flags' set to
     ‘NULL’.

 -- C Function: int PyRun_InteractiveLoopFlags (FILE *fp, const char
          *filename, PyCompilerFlags *flags)

     Read and execute statements from a file associated with an
     interactive device until EOF is reached.  The user will be prompted
     using ‘sys.ps1’ and ‘sys.ps2’.  'filename' is decoded from the
     *note filesystem encoding and error handler: 53e.  Returns ‘0’ at
     EOF or a negative number upon failure.

 -- C Variable: int (*PyOS_InputHook)(void)
     ' Part of the *note Stable ABI: 556.'  Can be set to point to a
     function with the prototype ‘int func(void)’.  The function will be
     called when Python’s interpreter prompt is about to become idle and
     wait for user input from the terminal.  The return value is
     ignored.  Overriding this hook can be used to integrate the
     interpreter’s prompt with other event loops, as done in
     ‘Modules/_tkinter.c’ in the Python source code.

     Changed in version 3.12: This function is only called from the
     *note main interpreter: 58a.

 -- C Variable: char *(*PyOS_ReadlineFunctionPointer)(FILE*, FILE*,
          const char*)

     Can be set to point to a function with the prototype ‘char
     *func(FILE *stdin, FILE *stdout, char *prompt)’, overriding the
     default function used to read a single line of input at the
     interpreter’s prompt.  The function is expected to output the
     string 'prompt' if it’s not ‘NULL’, and then read a line of input
     from the provided standard input file, returning the resulting
     string.  For example, The *note readline: ba. module sets this hook
     to provide line-editing and tab-completion features.

     The result must be a string allocated by *note PyMem_RawMalloc():
     393. or *note PyMem_RawRealloc(): 395, or ‘NULL’ if an error
     occurred.

     Changed in version 3.4: The result must be allocated by *note
     PyMem_RawMalloc(): 393. or *note PyMem_RawRealloc(): 395, instead
     of being allocated by *note PyMem_Malloc(): c87. or *note
     PyMem_Realloc(): 106f.

     Changed in version 3.12: This function is only called from the
     *note main interpreter: 58a.

 -- C Function: *note PyObject: 33a. *PyRun_String (const char *str, int
          start, PyObject *globals, PyObject *locals)
     'Return value: New reference.'  This is a simplified interface to
     *note PyRun_StringFlags(): 4e8e. below, leaving 'flags' set to
     ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyRun_StringFlags (const char
          *str, int start, PyObject *globals, PyObject *locals,
          PyCompilerFlags *flags)
     'Return value: New reference.'  Execute Python source code from
     'str' in the context specified by the objects 'globals' and
     'locals' with the compiler flags specified by 'flags'.  'globals'
     must be a dictionary; 'locals' can be any object that implements
     the mapping protocol.  The parameter 'start' specifies the start
     symbol and must be one of the *note available start symbols: 4e8f.

     Returns the result of executing the code as a Python object, or
     ‘NULL’ if an exception was raised.

 -- C Function: *note PyObject: 33a. *PyRun_File (FILE *fp, const char
          *filename, int start, PyObject *globals, PyObject *locals)
     'Return value: New reference.'  This is a simplified interface to
     *note PyRun_FileExFlags(): 4e91. below, leaving 'closeit' set to
     ‘0’ and 'flags' set to ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyRun_FileEx (FILE *fp, const char
          *filename, int start, PyObject *globals, PyObject *locals, int
          closeit)
     'Return value: New reference.'  This is a simplified interface to
     *note PyRun_FileExFlags(): 4e91. below, leaving 'flags' set to
     ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyRun_FileFlags (FILE *fp, const
          char *filename, int start, PyObject *globals, PyObject
          *locals, PyCompilerFlags *flags)
     'Return value: New reference.'  This is a simplified interface to
     *note PyRun_FileExFlags(): 4e91. below, leaving 'closeit' set to
     ‘0’.

 -- C Function: *note PyObject: 33a. *PyRun_FileExFlags (FILE *fp, const
          char *filename, int start, PyObject *globals, PyObject
          *locals, int closeit, PyCompilerFlags *flags)
     'Return value: New reference.'  Similar to *note
     PyRun_StringFlags(): 4e8e, but the Python source code is read from
     'fp' instead of an in-memory string.  'filename' should be the name
     of the file, it is decoded from the *note filesystem encoding and
     error handler: 53e.  If 'closeit' is true, the file is closed
     before *note PyRun_FileExFlags(): 4e91. returns.

 -- C Function: *note PyObject: 33a. *Py_CompileString (const char *str,
          const char *filename, int start)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is a simplified interface to *note
     Py_CompileStringFlags(): 4e94. below, leaving 'flags' set to
     ‘NULL’.

 -- C Function: *note PyObject: 33a. *Py_CompileStringFlags (const char
          *str, const char *filename, int start, PyCompilerFlags *flags)
     'Return value: New reference.'  This is a simplified interface to
     *note Py_CompileStringExFlags(): 4e95. below, with 'optimize' set
     to ‘-1’.

 -- C Function: *note PyObject: 33a. *Py_CompileStringObject (const char
          *str, PyObject *filename, int start, PyCompilerFlags *flags,
          int optimize)
     'Return value: New reference.'  Parse and compile the Python source
     code in 'str', returning the resulting code object.  The start
     symbol is given by 'start'; this can be used to constrain the code
     which can be compiled and should be *note available start symbols:
     4e8f.  The filename specified by 'filename' is used to construct
     the code object and may appear in tracebacks or *note SyntaxError:
     18d. exception messages.  This returns ‘NULL’ if the code cannot be
     parsed or compiled.

     The integer 'optimize' specifies the optimization level of the
     compiler; a value of ‘-1’ selects the optimization level of the
     interpreter as given by *note -O: de3. options.  Explicit levels
     are ‘0’ (no optimization; ‘__debug__’ is true), ‘1’ (asserts are
     removed, ‘__debug__’ is false) or ‘2’ (docstrings are removed too).

     Added in version 3.4.

 -- C Function: *note PyObject: 33a. *Py_CompileStringExFlags (const
          char *str, const char *filename, int start, PyCompilerFlags
          *flags, int optimize)
     'Return value: New reference.'  Like *note
     Py_CompileStringObject(): 4e96, but 'filename' is a byte string
     decoded from the *note filesystem encoding and error handler: 53e.

     Added in version 3.2.

 -- C Function: *note PyObject: 33a. *PyEval_EvalCode (PyObject *co,
          PyObject *globals, PyObject *locals)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is a simplified interface to *note PyEval_EvalCodeEx():
     187d, with just the code object, and global and local variables.
     The other arguments are set to ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyEval_EvalCodeEx (PyObject *co,
          PyObject *globals, PyObject *locals, PyObject *const *args,
          int argcount, PyObject *const *kws, int kwcount, PyObject
          *const *defs, int defcount, PyObject *kwdefs, PyObject
          *closure)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Evaluate a precompiled code object, given a particular
     environment for its evaluation.  This environment consists of a
     dictionary of global variables, a mapping object of local
     variables, arrays of arguments, keywords and defaults, a dictionary
     of default values for *note keyword-only: 2a5. arguments and a
     closure tuple of cells.

 -- C Function: *note PyObject: 33a. *PyEval_EvalFrame (PyFrameObject
          *f)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Evaluate an execution frame.  This is a simplified interface
     to *note PyEval_EvalFrameEx(): 106b, for backward compatibility.

 -- C Function: *note PyObject: 33a. *PyEval_EvalFrameEx (PyFrameObject
          *f, int throwflag)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is the main, unvarnished function of Python
     interpretation.  The code object associated with the execution
     frame 'f' is executed, interpreting bytecode and executing calls as
     needed.  The additional 'throwflag' parameter can mostly be ignored
     - if true, then it causes an exception to immediately be thrown;
     this is used for the *note throw(): 4fb. methods of generator
     objects.

     Changed in version 3.4: This function now includes a debug
     assertion to help ensure that it does not silently discard an
     active exception.

 -- C Function: int PyEval_MergeCompilerFlags (PyCompilerFlags *cf)

     This function changes the flags of the current evaluation frame,
     and returns true on success, false on failure.

 -- C Struct: struct PyCompilerFlags

     This is the structure used to hold compiler flags.  In cases where
     code is only being compiled, it is passed as ‘int flags’, and in
     cases where code is being executed, it is passed as
     ‘PyCompilerFlags *flags’.  In this case, ‘from __future__ import’
     can modify 'flags'.

     Whenever ‘PyCompilerFlags *flags’ is ‘NULL’, *note cf_flags: 4e98.
     is treated as equal to ‘0’, and any modification due to ‘from
     __future__ import’ is discarded.

      -- C Member: int cf_flags

          Compiler flags.

      -- C Member: int cf_feature_version

          'cf_feature_version' is the minor Python version.  It should
          be initialized to ‘PY_MINOR_VERSION’.

          The field is ignored by default, it is used if and only if
          ‘PyCF_ONLY_AST’ flag is set in *note cf_flags: 4e98.

     Changed in version 3.8: Added 'cf_feature_version' field.

     The available compiler flags are accessible as macros:

      -- C Macro: PyCF_ALLOW_TOP_LEVEL_AWAIT
      -- C Macro: PyCF_ONLY_AST
      -- C Macro: PyCF_OPTIMIZED_AST
      -- C Macro: PyCF_TYPE_COMMENTS

          See *note compiler flags: 231f. in documentation of the ‘ast’
          Python module, which exports these constants under the same
          names.

     The “‘PyCF’” flags above can be combined with “‘CO_FUTURE’” flags
     such as *note CO_FUTURE_ANNOTATIONS: 4e9e. to enable features
     normally selectable using *note future statements: 189.  See *note
     Code Object Flags: 4e9f. for a complete list.

* Menu:

* Available start symbols::
* Stack Effects::


File: python.info,  Node: Available start symbols,  Next: Stack Effects,  Up: The Very High Level Layer

7.3.1 Available start symbols
-----------------------------

 -- C Variable: int Py_eval_input

     The start symbol from the Python grammar for isolated expressions;
     for use with *note Py_CompileString(): 88c.

 -- C Variable: int Py_file_input

     The start symbol from the Python grammar for sequences of
     statements as read from a file or other source; for use with *note
     Py_CompileString(): 88c.  This is the symbol to use when compiling
     arbitrarily long Python source code.

 -- C Variable: int Py_single_input

     The start symbol from the Python grammar for a single statement;
     for use with *note Py_CompileString(): 88c.  This is the symbol
     used for the interactive interpreter loop.

 -- C Variable: int Py_func_type_input

     The start symbol from the Python grammar for a function type; for
     use with *note Py_CompileString(): 88c.  This is used to parse
     “signature type comments” from PEP 484(1).

     This requires the *note PyCF_ONLY_AST: 4e9b. flag to be set.

     See also
     ........

        * *note ast.FunctionType: 4826.

        * PEP 484(2)

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0484/


File: python.info,  Node: Stack Effects,  Prev: Available start symbols,  Up: The Very High Level Layer

7.3.2 Stack Effects
-------------------

See also
........

*note dis.stack_effect(): f69.

 -- C Macro: PY_INVALID_STACK_EFFECT

     Sentinel value representing an invalid stack effect.

     This is currently equivalent to ‘INT_MAX’.

     Added in version 3.8.

 -- C Function: int PyCompile_OpcodeStackEffect (int opcode, int oparg)

     Compute the stack effect of 'opcode' with argument 'oparg'.

     On success, this function returns the stack effect; on failure,
     this returns *note PY_INVALID_STACK_EFFECT: 4ea2.

     Added in version 3.4.

 -- C Function: int PyCompile_OpcodeStackEffectWithJump (int opcode, int
          oparg, int jump)

     Similar to *note PyCompile_OpcodeStackEffect(): 4ea3, but don’t
     include the stack effect of jumping if 'jump' is zero.

     If 'jump' is ‘0’, this will not include the stack effect of
     jumping, but if 'jump' is ‘1’ or ‘-1’, this will include it.

     On success, this function returns the stack effect; on failure,
     this returns *note PY_INVALID_STACK_EFFECT: 4ea2.

     Added in version 3.8.


File: python.info,  Node: Reference Counting,  Next: Exception Handling,  Prev: The Very High Level Layer,  Up: Python/C API Reference Manual

7.4 Reference Counting
======================

The functions and macros in this section are used for managing reference
counts of Python objects.

 -- C Function: *note Py_ssize_t: a6e. Py_REFCNT (PyObject *o)

     Get the reference count of the Python object 'o'.

     Note that the returned value may not actually reflect how many
     references to the object are actually held.  For example, some
     objects are *note immortal: 45dd. and have a very high refcount
     that does not reflect the actual number of references.
     Consequently, do not rely on the returned value to be accurate,
     other than a value of 0 or 1.

     Use the *note Py_SET_REFCNT(): 8b2. function to set an object
     reference count.

     Changed in version 3.10: *note Py_REFCNT(): 8b1. is changed to the
     inline static function.

     Changed in version 3.11: The parameter type is no longer const
     *note PyObject: 33a.*.

 -- C Function: void Py_SET_REFCNT (PyObject *o, Py_ssize_t refcnt)

     Set the object 'o' reference counter to 'refcnt'.

     On *note Python build with Free Threading: 1f1f, if 'refcnt' is
     larger than ‘UINT32_MAX’, the object is made *note immortal: 45dd.

     This function has no effect on *note immortal: 45dd. objects.

     Added in version 3.9.

     Changed in version 3.12: Immortal objects are not modified.

 -- C Function: void Py_INCREF (PyObject *o)

     Indicate taking a new *note strong reference: 33e. to object 'o',
     indicating it is in use and should not be destroyed.

     This function has no effect on *note immortal: 45dd. objects.

     This function is usually used to convert a *note borrowed
     reference: 33f. to a *note strong reference: 33e. in-place.  The
     *note Py_NewRef(): 8a1. function can be used to create a new strong
     reference.

     When done using the object, release is by calling *note
     Py_DECREF(): 572.

     The object must not be ‘NULL’; if you aren’t sure that it isn’t
     ‘NULL’, use *note Py_XINCREF(): a73.

     Do not expect this function to actually modify 'o' in any way.  For
     at least some objects(1), this function has no effect.

     Changed in version 3.12: Immortal objects are not modified.

 -- C Function: void Py_XINCREF (PyObject *o)

     Similar to *note Py_INCREF(): 571, but the object 'o' can be
     ‘NULL’, in which case this has no effect.

     See also *note Py_XNewRef(): 8a2.

 -- C Function: *note PyObject: 33a. *Py_NewRef (PyObject *o)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Create a
     new *note strong reference: 33e. to an object: call *note
     Py_INCREF(): 571. on 'o' and return the object 'o'.

     When the *note strong reference: 33e. is no longer needed, *note
     Py_DECREF(): 572. should be called on it to release the reference.

     The object 'o' must not be ‘NULL’; use *note Py_XNewRef(): 8a2. if
     'o' can be ‘NULL’.

     For example:

          Py_INCREF(obj);
          self->attr = obj;

     can be written as:

          self->attr = Py_NewRef(obj);

     See also *note Py_INCREF(): 571.

     Added in version 3.10.

 -- C Function: *note PyObject: 33a. *Py_XNewRef (PyObject *o)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Similar
     to *note Py_NewRef(): 8a1, but the object 'o' can be NULL.

     If the object 'o' is ‘NULL’, the function just returns ‘NULL’.

     Added in version 3.10.

 -- C Function: void Py_DECREF (PyObject *o)

     Release a *note strong reference: 33e. to object 'o', indicating
     the reference is no longer used.

     This function has no effect on *note immortal: 45dd. objects.

     Once the last *note strong reference: 33e. is released (i.e.  the
     object’s reference count reaches 0), the object’s type’s
     deallocation function (which must not be ‘NULL’) is invoked.

     This function is usually used to delete a *note strong reference:
     33e. before exiting its scope.

     The object must not be ‘NULL’; if you aren’t sure that it isn’t
     ‘NULL’, use *note Py_XDECREF(): 792.

     Do not expect this function to actually modify 'o' in any way.  For
     at least some objects(2), this function has no effect.

          Warning: The deallocation function can cause arbitrary Python
          code to be invoked (e.g.  when a class instance with a *note
          __del__(): 1038. method is deallocated).  While exceptions in
          such code are not propagated, the executed code has free
          access to all Python global variables.  This means that any
          object that is reachable from a global variable should be in a
          consistent state before *note Py_DECREF(): 572. is invoked.
          For example, code to delete an object from a list should copy
          a reference to the deleted object in a temporary variable,
          update the list data structure, and then call ‘Py_DECREF()’
          for the temporary variable.

     Changed in version 3.12: Immortal objects are not modified.

 -- C Function: void Py_XDECREF (PyObject *o)

     Similar to *note Py_DECREF(): 572, but the object 'o' can be
     ‘NULL’, in which case this has no effect.  The same warning from
     ‘Py_DECREF()’ applies here as well.

 -- C Function: void Py_CLEAR (PyObject *o)

     Release a *note strong reference: 33e. for object 'o'.  The object
     may be ‘NULL’, in which case the macro has no effect; otherwise the
     effect is the same as for *note Py_DECREF(): 572, except that the
     argument is also set to ‘NULL’.  The warning for ‘Py_DECREF()’ does
     not apply with respect to the object passed because the macro
     carefully uses a temporary variable and sets the argument to ‘NULL’
     before releasing the reference.

     It is a good idea to use this macro whenever releasing a reference
     to an object that might be traversed during garbage collection.

     Changed in version 3.12: The macro argument is now only evaluated
     once.  If the argument has side effects, these are no longer
     duplicated.

 -- C Function: void Py_IncRef (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Indicate taking a new *note
     strong reference: 33e. to object 'o'.  A function version of *note
     Py_XINCREF(): a73.  It can be used for runtime dynamic embedding of
     Python.

 -- C Function: void Py_DecRef (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Release a *note strong
     reference: 33e. to object 'o'.  A function version of *note
     Py_XDECREF(): 792.  It can be used for runtime dynamic embedding of
     Python.

 -- C Macro: Py_SETREF (dst, src)

     Macro safely releasing a *note strong reference: 33e. to object
     'dst' and setting 'dst' to 'src'.

     As in case of *note Py_CLEAR(): 57b, “the obvious” code can be
     deadly:

          Py_DECREF(dst);
          dst = src;

     The safe way is:

          Py_SETREF(dst, src);

     That arranges to set 'dst' to 'src' 'before' releasing the
     reference to the old value of 'dst', so that any code triggered as
     a side-effect of 'dst' getting torn down no longer believes 'dst'
     points to a valid object.

     Added in version 3.6.

     Changed in version 3.12: The macro arguments are now only evaluated
     once.  If an argument has side effects, these are no longer
     duplicated.

 -- C Macro: Py_XSETREF (dst, src)

     Variant of *note Py_SETREF: 57c. macro that uses *note
     Py_XDECREF(): 792. instead of *note Py_DECREF(): 572.

     Added in version 3.6.

     Changed in version 3.12: The macro arguments are now only evaluated
     once.  If an argument has side effects, these are no longer
     duplicated.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0683/

   (2) https://peps.python.org/pep-0683/


File: python.info,  Node: Exception Handling,  Next: Utilities<2>,  Prev: Reference Counting,  Up: Python/C API Reference Manual

7.5 Exception Handling
======================

The functions described in this chapter will let you handle and raise
Python exceptions.  It is important to understand some of the basics of
Python exception handling.  It works somewhat like the POSIX ‘errno’
variable: there is a global indicator (per thread) of the last error
that occurred.  Most C API functions don’t clear this on success, but
will set it to indicate the cause of the error on failure.  Most C API
functions also return an error indicator, usually ‘NULL’ if they are
supposed to return a pointer, or ‘-1’ if they return an integer
(exception: the ‘PyArg_*’ functions return ‘1’ for success and ‘0’ for
failure).

Concretely, the error indicator consists of three object pointers: the
exception’s type, the exception’s value, and the traceback object.  Any
of those pointers can be ‘NULL’ if non-set (although some combinations
are forbidden, for example you can’t have a non-‘NULL’ traceback if the
exception type is ‘NULL’).

When a function must fail because some function it called failed, it
generally doesn’t set the error indicator; the function it called
already set it.  It is responsible for either handling the error and
clearing the exception or returning after cleaning up any resources it
holds (such as object references or memory allocations); it should 'not'
continue normally if it is not prepared to handle the error.  If
returning due to an error, it is important to indicate to the caller
that an error has been set.  If the error is not handled or carefully
propagated, additional calls into the Python/C API may not behave as
intended and may fail in mysterious ways.

     Note: The error indicator is 'not' the result of *note
     sys.exc_info(): 68d.  The former corresponds to an exception that
     is not yet caught (and is therefore still propagating), while the
     latter returns an exception after it is caught (and has therefore
     stopped propagating).

* Menu:

* Printing and clearing::
* Raising exceptions::
* Issuing warnings::
* Querying the error indicator::
* Signal Handling: Signal Handling<2>.
* Exception Classes::
* Exception Objects::
* Unicode Exception Objects::
* Recursion Control::
* Exception and warning types::
* Tracebacks::


File: python.info,  Node: Printing and clearing,  Next: Raising exceptions,  Up: Exception Handling

7.5.1 Printing and clearing
---------------------------

 -- C Function: void PyErr_Clear ()
     ' Part of the *note Stable ABI: 556.'  Clear the error indicator.
     If the error indicator is not set, there is no effect.

 -- C Function: void PyErr_PrintEx (int set_sys_last_vars)
     ' Part of the *note Stable ABI: 556.'  Print a standard traceback
     to ‘sys.stderr’ and clear the error indicator.  'Unless' the error
     is a ‘SystemExit’, in that case no traceback is printed and the
     Python process will exit with the error code specified by the
     ‘SystemExit’ instance.

     Call this function 'only' when the error indicator is set.
     Otherwise it will cause a fatal error!

     If 'set_sys_last_vars' is nonzero, the variable *note sys.last_exc:
     4c1. is set to the printed exception.  For backwards compatibility,
     the deprecated variables *note sys.last_type: 4c2, *note
     sys.last_value: 4c3. and *note sys.last_traceback: 4c4. are also
     set to the type, value and traceback of this exception,
     respectively.

     Changed in version 3.12: The setting of *note sys.last_exc: 4c1.
     was added.

 -- C Function: void PyErr_Print ()
     ' Part of the *note Stable ABI: 556.'  Alias for
     ‘PyErr_PrintEx(1)’.

 -- C Function: void PyErr_WriteUnraisable (PyObject *obj)
     ' Part of the *note Stable ABI: 556.'  Call *note
     sys.unraisablehook(): 1f7. using the current exception and 'obj'
     argument.

     This utility function prints a warning message to ‘sys.stderr’ when
     an exception has been set but it is impossible for the interpreter
     to actually raise the exception.  It is used, for example, when an
     exception occurs in an *note __del__(): 1038. method.

     The function is called with a single argument 'obj' that identifies
     the context in which the unraisable exception occurred.  If
     possible, the repr of 'obj' will be printed in the warning message.
     If 'obj' is ‘NULL’, only the traceback is printed.

     An exception must be set when calling this function.

     Changed in version 3.4: Print a traceback.  Print only traceback if
     'obj' is ‘NULL’.

     Changed in version 3.8: Use *note sys.unraisablehook(): 1f7.

 -- C Function: void PyErr_FormatUnraisable (const char *format, ...)

     Similar to *note PyErr_WriteUnraisable(): 350, but the 'format' and
     subsequent parameters help format the warning message; they have
     the same meaning and values as in *note PyUnicode_FromFormat():
     38d.  ‘PyErr_WriteUnraisable(obj)’ is roughly equivalent to
     ‘PyErr_FormatUnraisable("Exception ignored in: %R", obj)’.  If
     'format' is ‘NULL’, only the traceback is printed.

     Added in version 3.13.

 -- C Function: void PyErr_DisplayException (PyObject *exc)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Print
     the standard traceback display of ‘exc’ to ‘sys.stderr’, including
     chained exceptions and notes.

     Added in version 3.12.


File: python.info,  Node: Raising exceptions,  Next: Issuing warnings,  Prev: Printing and clearing,  Up: Exception Handling

7.5.2 Raising exceptions
------------------------

These functions help you set the current thread’s error indicator.  For
convenience, some of these functions will always return a ‘NULL’ pointer
for use in a ‘return’ statement.

 -- C Function: void PyErr_SetString (PyObject *type, const char
          *message)
     ' Part of the *note Stable ABI: 556.'  This is the most common way
     to set the error indicator.  The first argument specifies the
     exception type; it is normally one of the standard exceptions, e.g.
     *note PyExc_RuntimeError: 4cce.  You need not create a new *note
     strong reference: 33e. to it (e.g.  with *note Py_INCREF(): 571.).
     The second argument is an error message; it is decoded from
     ‘'utf-8'’.

 -- C Function: void PyErr_SetObject (PyObject *type, PyObject *value)
     ' Part of the *note Stable ABI: 556.'  This function is similar to
     *note PyErr_SetString(): 57f. but lets you specify an arbitrary
     Python object for the “value” of the exception.

 -- C Function: *note PyObject: 33a. *PyErr_Format (PyObject *exception,
          const char *format, ...)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'
     This function sets the error indicator and returns ‘NULL’.
     'exception' should be a Python exception class.  The 'format' and
     subsequent parameters help format the error message; they have the
     same meaning and values as in *note PyUnicode_FromFormat(): 38d.
     'format' is an ASCII-encoded string.

 -- C Function: *note PyObject: 33a. *PyErr_FormatV (PyObject
          *exception, const char *format, va_list vargs)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.
     since version 3.5.'  Same as *note PyErr_Format(): ee5, but taking
     a ‘va_list’ argument rather than a variable number of arguments.

     Added in version 3.5.

 -- C Function: void PyErr_SetNone (PyObject *type)
     ' Part of the *note Stable ABI: 556.'  This is a shorthand for
     ‘PyErr_SetObject(type, Py_None)’.

 -- C Function: int PyErr_BadArgument ()
     ' Part of the *note Stable ABI: 556.'  This is a shorthand for
     ‘PyErr_SetString(PyExc_TypeError, message)’, where 'message'
     indicates that a built-in operation was invoked with an illegal
     argument.  It is mostly for internal use.

 -- C Function: *note PyObject: 33a. *PyErr_NoMemory ()
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'
     This is a shorthand for ‘PyErr_SetNone(PyExc_MemoryError)’; it
     returns ‘NULL’ so an object allocation function can write ‘return
     PyErr_NoMemory();’ when it runs out of memory.

 -- C Function: *note PyObject: 33a. *PyErr_SetFromErrno (PyObject
          *type)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'

     This is a convenience function to raise an exception when a C
     library function has returned an error and set the C variable
     ‘errno’.  It constructs a tuple object whose first item is the
     integer ‘errno’ value and whose second item is the corresponding
     error message (gotten from ‘strerror()’), and then calls
     ‘PyErr_SetObject(type, object)’.  On Unix, when the ‘errno’ value
     is ‘EINTR’, indicating an interrupted system call, this calls *note
     PyErr_CheckSignals(): 46a, and if that set the error indicator,
     leaves it set to that.  The function always returns ‘NULL’, so a
     wrapper function around a system call can write ‘return
     PyErr_SetFromErrno(type);’ when the system call returns an error.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetFromErrnoWithFilenameObject (PyObject *type,
          PyObject *filenameObject)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'
     Similar to *note PyErr_SetFromErrno(): 4b62, with the additional
     behavior that if 'filenameObject' is not ‘NULL’, it is passed to
     the constructor of 'type' as a third parameter.  In the case of
     *note OSError: 41a. exception, this is used to define the
     ‘filename’ attribute of the exception instance.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetFromErrnoWithFilenameObjects (PyObject *type,
          PyObject *filenameObject, PyObject *filenameObject2)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.
     since version 3.7.'  Similar to *note
     PyErr_SetFromErrnoWithFilenameObject(): 4c95, but takes a second
     filename object, for raising errors when a function that takes two
     filenames fails.

     Added in version 3.4.

 -- C Function: *note PyObject: 33a. *PyErr_SetFromErrnoWithFilename
          (PyObject *type, const char *filename)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'
     Similar to *note PyErr_SetFromErrnoWithFilenameObject(): 4c95, but
     the filename is given as a C string.  'filename' is decoded from
     the *note filesystem encoding and error handler: 53e.

 -- C Function: *note PyObject: 33a. *PyErr_SetFromWindowsErr (int ierr)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  This is a convenience function to
     raise *note OSError: 41a.  If called with 'ierr' of ‘0’, the error
     code returned by a call to ‘GetLastError()’ is used instead.  It
     calls the Win32 function ‘FormatMessage()’ to retrieve the Windows
     description of error code given by 'ierr' or ‘GetLastError()’, then
     it constructs a ‘OSError’ object with the *note winerror: 2447.
     attribute set to the error code, the *note strerror: 2448.
     attribute set to the corresponding error message (gotten from
     ‘FormatMessage()’), and then calls ‘PyErr_SetObject(PyExc_OSError,
     object)’.  This function always returns ‘NULL’.

     *note Availability: 1ef7.: Windows.

 -- C Function: *note PyObject: 33a. *PyErr_SetExcFromWindowsErr
          (PyObject *type, int ierr)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  Similar to *note
     PyErr_SetFromWindowsErr(): 4c97, with an additional parameter
     specifying the exception type to be raised.

     *note Availability: 1ef7.: Windows.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetFromWindowsErrWithFilename (int ierr, const char
          *filename)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  Similar to *note
     PyErr_SetFromWindowsErr(): 4c97, with the additional behavior that
     if 'filename' is not ‘NULL’, it is decoded from the filesystem
     encoding (*note os.fsdecode(): c75.) and passed to the constructor
     of *note OSError: 41a. as a third parameter to be used to define
     the ‘filename’ attribute of the exception instance.

     *note Availability: 1ef7.: Windows.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetExcFromWindowsErrWithFilenameObject (PyObject *type,
          int ierr, PyObject *filename)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  Similar to *note
     PyErr_SetExcFromWindowsErr(): 4c92, with the additional behavior
     that if 'filename' is not ‘NULL’, it is passed to the constructor
     of *note OSError: 41a. as a third parameter to be used to define
     the ‘filename’ attribute of the exception instance.

     *note Availability: 1ef7.: Windows.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetExcFromWindowsErrWithFilenameObjects (PyObject
          *type, int ierr, PyObject *filename, PyObject *filename2)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  Similar to *note
     PyErr_SetExcFromWindowsErrWithFilenameObject(): 4c93, but accepts a
     second filename object.

     *note Availability: 1ef7.: Windows.

     Added in version 3.4.

 -- C Function: *note PyObject: 33a.
          *PyErr_SetExcFromWindowsErrWithFilename (PyObject *type, int
          ierr, const char *filename)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556. on
     Windows since version 3.7.'  Similar to *note
     PyErr_SetFromWindowsErrWithFilename(): 1826, with an additional
     parameter specifying the exception type to be raised.

     *note Availability: 1ef7.: Windows.

 -- C Function: *note PyObject: 33a. *PyErr_SetImportError (PyObject
          *msg, PyObject *name, PyObject *path)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.
     since version 3.7.'  This is a convenience function to raise *note
     ImportError: 41c.  'msg' will be set as the exception’s message
     string.  'name' and 'path', both of which can be ‘NULL’, will be
     set as the ‘ImportError’’s respective ‘name’ and ‘path’ attributes.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyErr_SetImportErrorSubclass
          (PyObject *exception, PyObject *msg, PyObject *name, PyObject
          *path)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.
     since version 3.6.'  Much like *note PyErr_SetImportError(): d66.
     but this function allows for specifying a subclass of *note
     ImportError: 41c. to raise.

     Added in version 3.6.

 -- C Function: void PyErr_SyntaxLocationObject (PyObject *filename, int
          lineno, int col_offset)

     Set file, line, and offset information for the current exception.
     If the current exception is not a *note SyntaxError: 18d, then it
     sets additional attributes, which make the exception printing
     subsystem think the exception is a ‘SyntaxError’.

     Added in version 3.4.

 -- C Function: void PyErr_RangedSyntaxLocationObject (PyObject
          *filename, int lineno, int col_offset, int end_lineno, int
          end_col_offset)

     Similar to *note PyErr_SyntaxLocationObject(): 4ead, but also sets
     the 'end_lineno' and 'end_col_offset' information for the current
     exception.

     Added in version 3.10.

 -- C Function: void PyErr_SyntaxLocationEx (const char *filename, int
          lineno, int col_offset)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Like
     *note PyErr_SyntaxLocationObject(): 4ead, but 'filename' is a byte
     string decoded from the *note filesystem encoding and error
     handler: 53e.

     Added in version 3.2.

 -- C Function: void PyErr_SyntaxLocation (const char *filename, int
          lineno)
     ' Part of the *note Stable ABI: 556.'  Like *note
     PyErr_SyntaxLocationEx(): 4c9b, but the 'col_offset' parameter is
     omitted.

 -- C Function: void PyErr_BadInternalCall ()
     ' Part of the *note Stable ABI: 556.'  This is a shorthand for
     ‘PyErr_SetString(PyExc_SystemError, message)’, where 'message'
     indicates that an internal operation (e.g.  a Python/C API
     function) was invoked with an illegal argument.  It is mostly for
     internal use.

 -- C Function: *note PyObject: 33a. *PyErr_ProgramTextObject (PyObject
          *filename, int lineno)

     Get the source line in 'filename' at line 'lineno'.  'filename'
     should be a Python *note str: 44f. object.

     On success, this function returns a Python string object with the
     found line.  On failure, this function returns ‘NULL’ without an
     exception set.

 -- C Function: *note PyObject: 33a. *PyErr_ProgramText (const char
          *filename, int lineno)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyErr_ProgramTextObject(): 4eaf, but 'filename' is a const char*,
     which is decoded with the *note filesystem encoding and error
     handler: 53e, instead of a Python object reference.


File: python.info,  Node: Issuing warnings,  Next: Querying the error indicator,  Prev: Raising exceptions,  Up: Exception Handling

7.5.3 Issuing warnings
----------------------

Use these functions to issue warnings from C code.  They mirror similar
functions exported by the Python *note warnings: 112. module.  They
normally print a warning message to 'sys.stderr'; however, it is also
possible that the user has specified that warnings are to be turned into
errors, and in that case they will raise an exception.  It is also
possible that the functions raise an exception because of a problem with
the warning machinery.  The return value is ‘0’ if no exception is
raised, or ‘-1’ if an exception is raised.  (It is not possible to
determine whether a warning message is actually printed, nor what the
reason is for the exception; this is intentional.)  If an exception is
raised, the caller should do its normal exception handling (for example,
*note Py_DECREF(): 572. owned references and return an error value).

 -- C Function: int PyErr_WarnEx (PyObject *category, const char
          *message, Py_ssize_t stack_level)
     ' Part of the *note Stable ABI: 556.'  Issue a warning message.
     The 'category' argument is a warning category (see below) or
     ‘NULL’; the 'message' argument is a UTF-8 encoded string.
     'stack_level' is a positive number giving a number of stack frames;
     the warning will be issued from the currently executing line of
     code in that stack frame.  A 'stack_level' of 1 is the function
     calling *note PyErr_WarnEx(): 149b, 2 is the function above that,
     and so forth.

     Warning categories must be subclasses of *note PyExc_Warning:
     4cdf.; ‘PyExc_Warning’ is a subclass of *note PyExc_Exception:
     4cb3.; the default warning category is *note PyExc_RuntimeWarning:
     4ccf.  The standard Python warning categories are available as
     global variables whose names are enumerated at *note Warning types:
     4eb1.

     For information about warning control, see the documentation for
     the *note warnings: 112. module and the *note -W: 8d0. option in
     the command line documentation.  There is no C API for warning
     control.

 -- C Function: int PyErr_WarnExplicitObject (PyObject *category,
          PyObject *message, PyObject *filename, int lineno, PyObject
          *module, PyObject *registry)

     Issue a warning message with explicit control over all warning
     attributes.  This is a straightforward wrapper around the Python
     function *note warnings.warn_explicit(): d28.; see there for more
     information.  The 'module' and 'registry' arguments may be set to
     ‘NULL’ to get the default effect described there.

     Added in version 3.4.

 -- C Function: int PyErr_WarnExplicit (PyObject *category, const char
          *message, const char *filename, int lineno, const char
          *module, PyObject *registry)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyErr_WarnExplicitObject(): 4eb2. except that 'message' and
     'module' are UTF-8 encoded strings, and 'filename' is decoded from
     the *note filesystem encoding and error handler: 53e.

 -- C Function: int PyErr_WarnFormat (PyObject *category, Py_ssize_t
          stack_level, const char *format, ...)
     ' Part of the *note Stable ABI: 556.'  Function similar to *note
     PyErr_WarnEx(): 149b, but use *note PyUnicode_FromFormat(): 38d. to
     format the warning message.  'format' is an ASCII-encoded string.

     Added in version 3.2.

 -- C Function: int PyErr_WarnExplicitFormat (PyObject *category, const
          char *filename, int lineno, const char *module, PyObject
          *registry, const char *format, ...)

     Similar to *note PyErr_WarnExplicit(): 182c, but uses *note
     PyUnicode_FromFormat(): 38d. to format the warning message.
     'format' is an ASCII-encoded string.

     Added in version 3.2.

 -- C Function: int PyErr_ResourceWarning (PyObject *source, Py_ssize_t
          stack_level, const char *format, ...)
     ' Part of the *note Stable ABI: 556. since version 3.6.'  Function
     similar to *note PyErr_WarnFormat(): 4c9c, but 'category' is *note
     ResourceWarning: 244. and it passes 'source' to
     ‘warnings.WarningMessage’.

     Added in version 3.6.


File: python.info,  Node: Querying the error indicator,  Next: Signal Handling<2>,  Prev: Issuing warnings,  Up: Exception Handling

7.5.4 Querying the error indicator
----------------------------------

 -- C Function: *note PyObject: 33a. *PyErr_Occurred ()
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Test whether the error indicator is set.  If set, return the
     exception 'type' (the first argument to the last call to one of the
     ‘PyErr_Set*’ functions or to *note PyErr_Restore(): 3f9.).  If not
     set, return ‘NULL’.  You do not own a reference to the return
     value, so you do not need to *note Py_DECREF(): 572. it.

     The caller must hold the GIL.

          Note: Do not compare the return value to a specific exception;
          use *note PyErr_ExceptionMatches(): 4c10. instead, shown
          below.  (The comparison could easily fail since the exception
          may be an instance instead of a class, in the case of a class
          exception, or it may be a subclass of the expected exception.)

 -- C Function: int PyErr_ExceptionMatches (PyObject *exc)
     ' Part of the *note Stable ABI: 556.'  Equivalent to
     ‘PyErr_GivenExceptionMatches(PyErr_Occurred(), exc)’.  This should
     only be called when an exception is actually set; a memory access
     violation will occur if no exception has been raised.

 -- C Function: int PyErr_GivenExceptionMatches (PyObject *given,
          PyObject *exc)
     ' Part of the *note Stable ABI: 556.'  Return true if the 'given'
     exception matches the exception type in 'exc'.  If 'exc' is a class
     object, this also returns true when 'given' is an instance of a
     subclass.  If 'exc' is a tuple, all exception types in the tuple
     (and recursively in subtuples) are searched for a match.

 -- C Function: *note PyObject: 33a. *PyErr_GetRaisedException (void)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.12.'  Return the exception currently being raised,
     clearing the error indicator at the same time.  Return ‘NULL’ if
     the error indicator is not set.

     This function is used by code that needs to catch exceptions, or
     code that needs to save and restore the error indicator
     temporarily.

     For example:

          {
             PyObject *exc = PyErr_GetRaisedException();

             /* ... code that might produce other errors ... */

             PyErr_SetRaisedException(exc);
          }

     See also
     ........

     *note PyErr_GetHandledException(): 772, to save the exception
     currently being handled.

     Added in version 3.12.

 -- C Function: void PyErr_SetRaisedException (PyObject *exc)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Set
     'exc' as the exception currently being raised, clearing the
     existing exception if one is set.

          Warning: This call steals a reference to 'exc', which must be
          a valid exception.

     Added in version 3.12.

 -- C Function: void PyErr_Fetch (PyObject **ptype, PyObject **pvalue,
          PyObject **ptraceback)
     ' Part of the *note Stable ABI: 556.'

     Deprecated since version 3.12: Use *note
     PyErr_GetRaisedException(): 3f7. instead.

     Retrieve the error indicator into three variables whose addresses
     are passed.  If the error indicator is not set, set all three
     variables to ‘NULL’.  If it is set, it will be cleared and you own
     a reference to each object retrieved.  The value and traceback
     object may be ‘NULL’ even when the type object is not.

          Note: This function is normally only used by legacy code that
          needs to catch exceptions or save and restore the error
          indicator temporarily.

          For example:

               {
                  PyObject *type, *value, *traceback;
                  PyErr_Fetch(&type, &value, &traceback);

                  /* ... code that might produce other errors ... */

                  PyErr_Restore(type, value, traceback);
               }

 -- C Function: void PyErr_Restore (PyObject *type, PyObject *value,
          PyObject *traceback)
     ' Part of the *note Stable ABI: 556.'

     Deprecated since version 3.12: Use *note
     PyErr_SetRaisedException(): 3fa. instead.

     Set the error indicator from the three objects, 'type', 'value',
     and 'traceback', clearing the existing exception if one is set.  If
     the objects are ‘NULL’, the error indicator is cleared.  Do not
     pass a ‘NULL’ type and non-‘NULL’ value or traceback.  The
     exception type should be a class.  Do not pass an invalid exception
     type or value.  (Violating these rules will cause subtle problems
     later.)  This call takes away a reference to each object: you must
     own a reference to each object before the call and after the call
     you no longer own these references.  (If you don’t understand this,
     don’t use this function.  I warned you.)

          Note: This function is normally only used by legacy code that
          needs to save and restore the error indicator temporarily.
          Use *note PyErr_Fetch(): 3f6. to save the current error
          indicator.

 -- C Function: void PyErr_NormalizeException (PyObject **exc, PyObject
          **val, PyObject **tb)
     ' Part of the *note Stable ABI: 556.'

     Deprecated since version 3.12: Use *note
     PyErr_GetRaisedException(): 3f7. instead, to avoid any possible
     de-normalization.

     Under certain circumstances, the values returned by *note
     PyErr_Fetch(): 3f6. below can be “unnormalized”, meaning that
     ‘*exc’ is a class object but ‘*val’ is not an instance of the same
     class.  This function can be used to instantiate the class in that
     case.  If the values are already normalized, nothing happens.  The
     delayed normalization is implemented to improve performance.

          Note: This function 'does not' implicitly set the *note
          __traceback__: 130e. attribute on the exception value.  If
          setting the traceback appropriately is desired, the following
          additional snippet is needed:

               if (tb != NULL) {
                 PyException_SetTraceback(val, tb);
               }

 -- C Function: *note PyObject: 33a. *PyErr_GetHandledException (void)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Retrieve
     the active exception instance, as would be returned by *note
     sys.exception(): 68e.  This refers to an exception that was
     'already caught', not to an exception that was freshly raised.
     Returns a new reference to the exception or ‘NULL’.  Does not
     modify the interpreter’s exception state.

          Note: This function is not normally used by code that wants to
          handle exceptions.  Rather, it can be used when code needs to
          save and restore the exception state temporarily.  Use *note
          PyErr_SetHandledException(): 773. to restore or clear the
          exception state.

     Added in version 3.11.

 -- C Function: void PyErr_SetHandledException (PyObject *exc)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Set the
     active exception, as known from ‘sys.exception()’.  This refers to
     an exception that was 'already caught', not to an exception that
     was freshly raised.  To clear the exception state, pass ‘NULL’.

          Note: This function is not normally used by code that wants to
          handle exceptions.  Rather, it can be used when code needs to
          save and restore the exception state temporarily.  Use *note
          PyErr_GetHandledException(): 772. to get the exception state.

     Added in version 3.11.

 -- C Function: void PyErr_GetExcInfo (PyObject **ptype, PyObject
          **pvalue, PyObject **ptraceback)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Retrieve
     the old-style representation of the exception info, as known from
     *note sys.exc_info(): 68d.  This refers to an exception that was
     'already caught', not to an exception that was freshly raised.
     Returns new references for the three objects, any of which may be
     ‘NULL’.  Does not modify the exception info state.  This function
     is kept for backwards compatibility.  Prefer using *note
     PyErr_GetHandledException(): 772.

          Note: This function is not normally used by code that wants to
          handle exceptions.  Rather, it can be used when code needs to
          save and restore the exception state temporarily.  Use *note
          PyErr_SetExcInfo(): 774. to restore or clear the exception
          state.

     Added in version 3.3.

 -- C Function: void PyErr_SetExcInfo (PyObject *type, PyObject *value,
          PyObject *traceback)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Set the
     exception info, as known from ‘sys.exc_info()’.  This refers to an
     exception that was 'already caught', not to an exception that was
     freshly raised.  This function steals the references of the
     arguments.  To clear the exception state, pass ‘NULL’ for all three
     arguments.  This function is kept for backwards compatibility.
     Prefer using *note PyErr_SetHandledException(): 773.

          Note: This function is not normally used by code that wants to
          handle exceptions.  Rather, it can be used when code needs to
          save and restore the exception state temporarily.  Use *note
          PyErr_GetExcInfo(): 775. to read the exception state.

     Added in version 3.3.

     Changed in version 3.11: The ‘type’ and ‘traceback’ arguments are
     no longer used and can be NULL. The interpreter now derives them
     from the exception instance (the ‘value’ argument).  The function
     still steals references of all three arguments.


File: python.info,  Node: Signal Handling<2>,  Next: Exception Classes,  Prev: Querying the error indicator,  Up: Exception Handling

7.5.5 Signal Handling
---------------------

 -- C Function: int PyErr_CheckSignals ()
     ' Part of the *note Stable ABI: 556.'

     Handle external interruptions, such as signals or activating a
     debugger, whose processing has been delayed until it is safe to run
     Python code and/or raise exceptions.

     For example, pressing ‘Ctrl’-‘C’ causes a terminal to send the
     *note signal.SIGINT: 84a. signal.  This function executes the
     corresponding Python signal handler, which, by default, raises the
     *note KeyboardInterrupt: 9dc. exception.

     ‘PyErr_CheckSignals()’ should be called by long-running C code
     frequently enough so that the response appears immediate to humans.

     Handlers invoked by this function currently include:

        - Signal handlers, including Python functions registered using
          the *note signal: c6. module.

          Signal handlers are only run in the main thread of the main
          interpreter.

          (This is where the function got the name: originally, signals
          were the only way to interrupt the interpreter.)

        - Running the garbage collector, if necessary.

     If any handler raises an exception, immediately return ‘-1’ with
     that exception set.  Any remaining interruptions are left to be
     processed on the next *note PyErr_CheckSignals(): 46a. invocation,
     if appropriate.

     If all handlers finish successfully, or there are no handlers to
     run, return ‘0’.

     Changed in version 3.12: This function may now invoke the garbage
     collector.

 -- C Function: void PyErr_SetInterrupt ()
     ' Part of the *note Stable ABI: 556.'

     Simulate the effect of a ‘SIGINT’ signal arriving.  This is
     equivalent to ‘PyErr_SetInterruptEx(SIGINT)’.

          Note: This function is async-signal-safe.  It can be called
          without the *note GIL: 159. and from a C signal handler.

 -- C Function: int PyErr_SetInterruptEx (int signum)
     ' Part of the *note Stable ABI: 556. since version 3.10.'

     Simulate the effect of a signal arriving.  The next time *note
     PyErr_CheckSignals(): 46a. is called, the Python signal handler for
     the given signal number will be called.

     This function can be called by C code that sets up its own signal
     handling and wants Python signal handlers to be invoked as expected
     when an interruption is requested (for example when the user
     presses Ctrl-C to interrupt an operation).

     If the given signal isn’t handled by Python (it was set to *note
     signal.SIG_DFL: 1957. or *note signal.SIG_IGN: 1956.), it will be
     ignored.

     If 'signum' is outside of the allowed range of signal numbers, ‘-1’
     is returned.  Otherwise, ‘0’ is returned.  The error indicator is
     never changed by this function.

          Note: This function is async-signal-safe.  It can be called
          without the *note GIL: 159. and from a C signal handler.

     Added in version 3.10.

 -- C Function: int PySignal_SetWakeupFd (int fd)

     This utility function specifies a file descriptor to which the
     signal number is written as a single byte whenever a signal is
     received.  'fd' must be non-blocking.  It returns the previous such
     file descriptor.

     The value ‘-1’ disables the feature; this is the initial state.
     This is equivalent to *note signal.set_wakeup_fd(): b8c. in Python,
     but without any error checking.  'fd' should be a valid file
     descriptor.  The function should only be called from the main
     thread.

     Changed in version 3.5: On Windows, the function now also supports
     socket handles.


File: python.info,  Node: Exception Classes,  Next: Exception Objects,  Prev: Signal Handling<2>,  Up: Exception Handling

7.5.6 Exception Classes
-----------------------

 -- C Function: *note PyObject: 33a. *PyErr_NewException (const char
          *name, PyObject *base, PyObject *dict)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This utility function creates and returns a new exception
     class.  The 'name' argument must be the name of the new exception,
     a C string of the form ‘module.classname’.  The 'base' and 'dict'
     arguments are normally ‘NULL’.  This creates a class object derived
     from *note Exception: 9e5. (accessible in C as *note
     PyExc_Exception: 4cb3.).

     The *note __module__: 377. attribute of the new class is set to the
     first part (up to the last dot) of the 'name' argument, and the
     class name is set to the last part (after the last dot).  The
     'base' argument can be used to specify alternate base classes; it
     can either be only one class or a tuple of classes.  The 'dict'
     argument can be used to specify a dictionary of class variables and
     methods.

 -- C Function: *note PyObject: 33a. *PyErr_NewExceptionWithDoc (const
          char *name, const char *doc, PyObject *base, PyObject *dict)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Same as *note PyErr_NewException(): 12b0, except that the
     new exception class can easily be given a docstring: If 'doc' is
     non-‘NULL’, it will be used as the docstring for the exception
     class.

     Added in version 3.2.

 -- C Function: int PyExceptionClass_Check (PyObject *ob)

     Return non-zero if 'ob' is an exception class, zero otherwise.
     This function always succeeds.

 -- C Function: const char *PyExceptionClass_Name (PyObject *ob)
     ' Part of the *note Stable ABI: 556. since version 3.8.'  Return
     *note tp_name: 1a56. of the exception class 'ob'.


File: python.info,  Node: Exception Objects,  Next: Unicode Exception Objects,  Prev: Exception Classes,  Up: Exception Handling

7.5.7 Exception Objects
-----------------------

 -- C Function: int PyExceptionInstance_Check (PyObject *op)

     Return true if 'op' is an instance of *note BaseException: 5be,
     false otherwise.  This function always succeeds.

 -- C Macro: PyExceptionInstance_Class (op)

     Equivalent to *note Py_TYPE(op): 783.

 -- C Function: *note PyObject: 33a. *PyException_GetTraceback (PyObject
          *ex)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the traceback associated with the exception as a new
     reference, as accessible from Python through the *note
     __traceback__: 130e. attribute.  If there is no traceback
     associated, this returns ‘NULL’.

 -- C Function: int PyException_SetTraceback (PyObject *ex, PyObject
          *tb)
     ' Part of the *note Stable ABI: 556.'  Set the traceback associated
     with the exception to 'tb'.  Use ‘Py_None’ to clear it.

 -- C Function: *note PyObject: 33a. *PyException_GetContext (PyObject
          *ex)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the context (another exception instance during whose
     handling 'ex' was raised) associated with the exception as a new
     reference, as accessible from Python through the *note __context__:
     130f. attribute.  If there is no context associated, this returns
     ‘NULL’.

 -- C Function: void PyException_SetContext (PyObject *ex, PyObject
          *ctx)
     ' Part of the *note Stable ABI: 556.'  Set the context associated
     with the exception to 'ctx'.  Use ‘NULL’ to clear it.  There is no
     type check to make sure that 'ctx' is an exception instance.  This
     steals a reference to 'ctx'.

 -- C Function: *note PyObject: 33a. *PyException_GetCause (PyObject
          *ex)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the cause (either an exception instance, or ‘None’,
     set by ‘raise ... from ...’) associated with the exception as a new
     reference, as accessible from Python through the *note __cause__:
     1310. attribute.

 -- C Function: void PyException_SetCause (PyObject *ex, PyObject
          *cause)
     ' Part of the *note Stable ABI: 556.'  Set the cause associated
     with the exception to 'cause'.  Use ‘NULL’ to clear it.  There is
     no type check to make sure that 'cause' is either an exception
     instance or ‘None’.  This steals a reference to 'cause'.

     The *note __suppress_context__: 226d. attribute is implicitly set
     to ‘True’ by this function.

 -- C Function: *note PyObject: 33a. *PyException_GetArgs (PyObject *ex)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.12.'  Return *note args: 56f. of exception 'ex'.

 -- C Function: void PyException_SetArgs (PyObject *ex, PyObject *args)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Set
     *note args: 56f. of exception 'ex' to 'args'.

 -- C Function: *note PyObject: 33a. *PyUnstable_Exc_PrepReraiseStar
          (PyObject *orig, PyObject *excs)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Implement part of the interpreter’s implementation of ‘except*’.
     'orig' is the original exception that was caught, and 'excs' is the
     list of the exceptions that need to be raised.  This list contains
     the unhandled part of 'orig', if any, as well as the exceptions
     that were raised from the ‘except*’ clauses (so they have a
     different traceback from 'orig') and those that were reraised (and
     have the same traceback as 'orig').  Return the *note
     ExceptionGroup: 1b6. that needs to be reraised in the end, or
     ‘None’ if there is nothing to reraise.

     Added in version 3.12.


File: python.info,  Node: Unicode Exception Objects,  Next: Recursion Control,  Prev: Exception Objects,  Up: Exception Handling

7.5.8 Unicode Exception Objects
-------------------------------

The following functions are used to create and modify Unicode exceptions
from C.

 -- C Function: *note PyObject: 33a. *PyUnicodeDecodeError_Create (const
          char *encoding, const char *object, Py_ssize_t length,
          Py_ssize_t start, Py_ssize_t end, const char *reason)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a *note UnicodeDecodeError: a20. object with the
     attributes 'encoding', 'object', 'length', 'start', 'end' and
     'reason'.  'encoding' and 'reason' are UTF-8 encoded strings.

 -- C Function: *note PyObject: 33a. *PyUnicodeDecodeError_GetEncoding
          (PyObject *exc)
 -- C Function: *note PyObject: 33a. *PyUnicodeEncodeError_GetEncoding
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the 'encoding' attribute of the given exception
     object.

 -- C Function: *note PyObject: 33a. *PyUnicodeDecodeError_GetObject
          (PyObject *exc)
 -- C Function: *note PyObject: 33a. *PyUnicodeEncodeError_GetObject
          (PyObject *exc)
 -- C Function: *note PyObject: 33a. *PyUnicodeTranslateError_GetObject
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the 'object' attribute of the given exception object.

 -- C Function: int PyUnicodeDecodeError_GetStart (PyObject *exc,
          Py_ssize_t *start)
 -- C Function: int PyUnicodeEncodeError_GetStart (PyObject *exc,
          Py_ssize_t *start)
 -- C Function: int PyUnicodeTranslateError_GetStart (PyObject *exc,
          Py_ssize_t *start)
     ' Part of the *note Stable ABI: 556.'  Get the 'start' attribute of
     the given exception object and place it into '*start'.  'start'
     must not be ‘NULL’.  Return ‘0’ on success, ‘-1’ on failure.

 -- C Function: int PyUnicodeDecodeError_SetStart (PyObject *exc,
          Py_ssize_t start)
 -- C Function: int PyUnicodeEncodeError_SetStart (PyObject *exc,
          Py_ssize_t start)
 -- C Function: int PyUnicodeTranslateError_SetStart (PyObject *exc,
          Py_ssize_t start)
     ' Part of the *note Stable ABI: 556.'  Set the 'start' attribute of
     the given exception object to 'start'.  Return ‘0’ on success, ‘-1’
     on failure.

 -- C Function: int PyUnicodeDecodeError_GetEnd (PyObject *exc,
          Py_ssize_t *end)
 -- C Function: int PyUnicodeEncodeError_GetEnd (PyObject *exc,
          Py_ssize_t *end)
 -- C Function: int PyUnicodeTranslateError_GetEnd (PyObject *exc,
          Py_ssize_t *end)
     ' Part of the *note Stable ABI: 556.'  Get the 'end' attribute of
     the given exception object and place it into '*end'.  'end' must
     not be ‘NULL’.  Return ‘0’ on success, ‘-1’ on failure.

 -- C Function: int PyUnicodeDecodeError_SetEnd (PyObject *exc,
          Py_ssize_t end)
 -- C Function: int PyUnicodeEncodeError_SetEnd (PyObject *exc,
          Py_ssize_t end)
 -- C Function: int PyUnicodeTranslateError_SetEnd (PyObject *exc,
          Py_ssize_t end)
     ' Part of the *note Stable ABI: 556.'  Set the 'end' attribute of
     the given exception object to 'end'.  Return ‘0’ on success, ‘-1’
     on failure.

 -- C Function: *note PyObject: 33a. *PyUnicodeDecodeError_GetReason
          (PyObject *exc)
 -- C Function: *note PyObject: 33a. *PyUnicodeEncodeError_GetReason
          (PyObject *exc)
 -- C Function: *note PyObject: 33a. *PyUnicodeTranslateError_GetReason
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the 'reason' attribute of the given exception object.

 -- C Function: int PyUnicodeDecodeError_SetReason (PyObject *exc, const
          char *reason)
 -- C Function: int PyUnicodeEncodeError_SetReason (PyObject *exc, const
          char *reason)
 -- C Function: int PyUnicodeTranslateError_SetReason (PyObject *exc,
          const char *reason)
     ' Part of the *note Stable ABI: 556.'  Set the 'reason' attribute
     of the given exception object to 'reason'.  Return ‘0’ on success,
     ‘-1’ on failure.


File: python.info,  Node: Recursion Control,  Next: Exception and warning types,  Prev: Unicode Exception Objects,  Up: Exception Handling

7.5.9 Recursion Control
-----------------------

These two functions provide a way to perform safe recursive calls at the
C level, both in the core and in extension modules.  They are needed if
the recursive code does not necessarily invoke Python code (which tracks
its recursion depth automatically).  They are also not needed for
'tp_call' implementations because the *note call protocol: 586. takes
care of recursion handling.

 -- C Function: int Py_EnterRecursiveCall (const char *where)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Marks a
     point where a recursive C-level call is about to be performed.

     If ‘USE_STACKCHECK’ is defined, this function checks if the OS
     stack overflowed using *note PyOS_CheckStack(): 1947.  If this is
     the case, it sets a *note MemoryError: 15ab. and returns a nonzero
     value.

     The function then checks if the recursion limit is reached.  If
     this is the case, a *note RecursionError: d96. is set and a nonzero
     value is returned.  Otherwise, zero is returned.

     'where' should be a UTF-8 encoded string such as ‘" in instance
     check"’ to be concatenated to the *note RecursionError: d96.
     message caused by the recursion depth limit.

     Changed in version 3.9: This function is now also available in the
     *note limited API: 399.

 -- C Function: void Py_LeaveRecursiveCall (void)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Ends a
     *note Py_EnterRecursiveCall(): 97d.  Must be called once for each
     'successful' invocation of ‘Py_EnterRecursiveCall()’.

     Changed in version 3.9: This function is now also available in the
     *note limited API: 399.

Properly implementing *note tp_repr: 4bae. for container types requires
special recursion handling.  In addition to protecting the stack,
‘tp_repr’ also needs to track objects to prevent cycles.  The following
two functions facilitate this functionality.  Effectively, these are the
C equivalent to *note reprlib.recursive_repr(): 1238.

 -- C Function: int Py_ReprEnter (PyObject *object)
     ' Part of the *note Stable ABI: 556.'  Called at the beginning of
     the *note tp_repr: 4bae. implementation to detect cycles.

     If the object has already been processed, the function returns a
     positive integer.  In that case the *note tp_repr: 4bae.
     implementation should return a string object indicating a cycle.
     As examples, *note dict: 256. objects return ‘{...}’ and *note
     list: 614. objects return ‘[...]’.

     The function will return a negative integer if the recursion limit
     is reached.  In that case the *note tp_repr: 4bae. implementation
     should typically return ‘NULL’.

     Otherwise, the function returns zero and the *note tp_repr: 4bae.
     implementation can continue normally.

 -- C Function: void Py_ReprLeave (PyObject *object)
     ' Part of the *note Stable ABI: 556.'  Ends a *note Py_ReprEnter():
     4df5.  Must be called once for each invocation of ‘Py_ReprEnter()’
     that returns zero.

 -- C Function: int Py_GetRecursionLimit (void)
     ' Part of the *note Stable ABI: 556.'  Get the recursion limit for
     the current interpreter.  It can be set with *note
     Py_SetRecursionLimit(): 4df7.  The recursion limit prevents the
     Python interpreter stack from growing infinitely.

     This function cannot fail, and the caller must hold the *note GIL:
     159.

     See also
     ........

     *note sys.getrecursionlimit(): 4c7.

 -- C Function: void Py_SetRecursionLimit (int new_limit)
     ' Part of the *note Stable ABI: 556.'  Set the recursion limit for
     the current interpreter.

     This function cannot fail, and the caller must hold the *note GIL:
     159.

     See also
     ........

     *note sys.setrecursionlimit(): 4c6.


File: python.info,  Node: Exception and warning types,  Next: Tracebacks,  Prev: Recursion Control,  Up: Exception Handling

7.5.10 Exception and warning types
----------------------------------

All standard Python exceptions and warning categories are available as
global variables whose names are ‘PyExc_’ followed by the Python
exception name.  These have the type *note PyObject: 33a.*; they are all
class objects.

For completeness, here are all the variables:

* Menu:

* Exception types::
* OSError aliases::
* Warning types::


File: python.info,  Node: Exception types,  Next: OSError aliases,  Up: Exception and warning types

7.5.10.1 Exception types
........................

C name                                                 Python name
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Variable: *note PyObject: 33a.                   *note BaseException: 5be.
          *PyExc_BaseException                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note BaseExceptionGroup: 25f.
          *PyExc_BaseExceptionGroup                    
     ' Part of the *note Stable ABI: 556. since
     version 3.11.'

 -- C Variable: *note PyObject: 33a.                   *note Exception: 9e5.
          *PyExc_Exception                             
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ArithmeticError: 243d.
          *PyExc_ArithmeticError                       
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note AssertionError: 6ac.
          *PyExc_AssertionError                        
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note AttributeError: 34e.
          *PyExc_AttributeError                        
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note BlockingIOError: 1095.
          *PyExc_BlockingIOError                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note BrokenPipeError: 109a.
          *PyExc_BrokenPipeError                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note BufferError: 15e3.
          *PyExc_BufferError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ChildProcessError: 1096.
          *PyExc_ChildProcessError                     
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ConnectionAbortedError: 109b.
          *PyExc_ConnectionAbortedError                
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ConnectionError: e3c.
          *PyExc_ConnectionError                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ConnectionRefusedError: 109c.
          *PyExc_ConnectionRefusedError                
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ConnectionResetError: 109d.
          *PyExc_ConnectionResetError                  
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a. *PyExc_EOFError   *note EOFError: 1321.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyObject: 33a.                   *note FileExistsError: 105b.
          *PyExc_FileExistsError                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note FileNotFoundError: 42e.
          *PyExc_FileNotFoundError                     
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note FloatingPointError: 243e.
          *PyExc_FloatingPointError                    
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note GeneratorExit: 1414.
          *PyExc_GeneratorExit                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ImportError: 41c.
          *PyExc_ImportError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note IndentationError: 7ac.
          *PyExc_IndentationError                      
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note IndexError: 1585.
          *PyExc_IndexError                            
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note InterruptedError: db6.
          *PyExc_InterruptedError                      
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note IsADirectoryError: 1097.
          *PyExc_IsADirectoryError                     
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a. *PyExc_KeyError   *note KeyError: 345.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyObject: 33a.                   *note KeyboardInterrupt: 9dc.
          *PyExc_KeyboardInterrupt                     
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note LookupError: 238a.
          *PyExc_LookupError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note MemoryError: 15ab.
          *PyExc_MemoryError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ModuleNotFoundError: b61.
          *PyExc_ModuleNotFoundError                   
     ' Part of the *note Stable ABI: 556. since
     version 3.6.'

 -- C Variable: *note PyObject: 33a.                   *note NameError: 442.
          *PyExc_NameError                             
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note NotADirectoryError: 1098.
          *PyExc_NotADirectoryError                    
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note NotImplementedError: 228.
          *PyExc_NotImplementedError                   
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a. *PyExc_OSError    *note OSError: 41a.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyObject: 33a.                   *note OverflowError: 888.
          *PyExc_OverflowError                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note PermissionError: d6b.
          *PyExc_PermissionError                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ProcessLookupError: 1099.
          *PyExc_ProcessLookupError                    
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note PythonFinalizationError: 14d.
          *PyExc_PythonFinalizationError               

 -- C Variable: *note PyObject: 33a.                   *note RecursionError: d96.
          *PyExc_RecursionError                        
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note ReferenceError: 155d.
          *PyExc_ReferenceError                        
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note RuntimeError: 195.
          *PyExc_RuntimeError                          
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note StopAsyncIteration: 1bbe.
          *PyExc_StopAsyncIteration                    
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note StopIteration: c1b.
          *PyExc_StopIteration                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note SyntaxError: 18d.
          *PyExc_SyntaxError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note SystemError: 578.
          *PyExc_SystemError                           
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note SystemExit: d69.
          *PyExc_SystemExit                            
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a. *PyExc_TabError   *note TabError: 546.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyObject: 33a.                   *note TimeoutError: 83b.
          *PyExc_TimeoutError                          
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note TypeError: 2c3.
          *PyExc_TypeError                             
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnboundLocalError: 1586.
          *PyExc_UnboundLocalError                     
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnicodeDecodeError: a20.
          *PyExc_UnicodeDecodeError                    
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnicodeEncodeError: 67a.
          *PyExc_UnicodeEncodeError                    
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnicodeError: 12eb.
          *PyExc_UnicodeError                          
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnicodeTranslateError: 2456.
          *PyExc_UnicodeTranslateError                 
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ValueError: 202.
          *PyExc_ValueError                            
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ZeroDivisionError: 94f.
          *PyExc_ZeroDivisionError                     
     ' Part of the *note Stable ABI: 556.'

Added in version 3.3: *note PyExc_BlockingIOError: 4ca6, *note
PyExc_BrokenPipeError: 4ca7, *note PyExc_ChildProcessError: 4caa, *note
PyExc_ConnectionError: 4cac, *note PyExc_ConnectionAbortedError: 4cab,
*note PyExc_ConnectionRefusedError: 4cad, *note
PyExc_ConnectionResetError: 4cae, *note PyExc_FileExistsError: 4cb4,
*note PyExc_FileNotFoundError: 4cb5, *note PyExc_InterruptedError: 4cbe,
*note PyExc_IsADirectoryError: 4cbf, *note PyExc_NotADirectoryError:
4cc6, *note PyExc_PermissionError: 4cca, *note PyExc_ProcessLookupError:
4ccb. and *note PyExc_TimeoutError: 4cd7. were introduced following PEP
3151(1).

Added in version 3.5: *note PyExc_StopAsyncIteration: 4cd0. and *note
PyExc_RecursionError: ee6.

Added in version 3.6: *note PyExc_ModuleNotFoundError: 4cc4.

Added in version 3.11: *note PyExc_BaseExceptionGroup: 4ca5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3151/


File: python.info,  Node: OSError aliases,  Next: Warning types,  Prev: Exception types,  Up: Exception and warning types

7.5.10.2 OSError aliases
........................

The following are a compatibility aliases to *note PyExc_OSError: 4b65.

Changed in version 3.3: These aliases used to be separate exception
types.

C name                                Python name                           Notes
                                                                            
------------------------------------------------------------------------------------------------------------------
                                                                            
 -- C Variable:                       *note OSError: 41a.
          *note PyObject: 33a.        
          *PyExc_EnvironmentError
     ' Part of the
     *note Stable ABI: 556.'

 -- C Variable:                       *note OSError: 41a.
          *note PyObject: 33a.        
          *PyExc_IOError
     ' Part of the
     *note Stable ABI: 556.'

 -- C Variable:                       *note OSError: 41a.                   *note [win]: 4ec5.
          *note PyObject: 33a.                                              
          *PyExc_WindowsError
     ' Part of the
     *note Stable ABI: 556. on
     Windows since version 3.7.'

Notes:

(win) ‘PyExc_WindowsError’ is only defined on Windows; protect code that
uses this by testing that the preprocessor macro ‘MS_WINDOWS’ is
defined.


File: python.info,  Node: Warning types,  Prev: OSError aliases,  Up: Exception and warning types

7.5.10.3 Warning types
......................

C name                                                 Python name
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Variable: *note PyObject: 33a. *PyExc_Warning    *note Warning: 246c.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyObject: 33a.                   *note BytesWarning: c43.
          *PyExc_BytesWarning                          
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note DeprecationWarning: 1a5.
          *PyExc_DeprecationWarning                    
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note EncodingWarning: 1ee5.
          *PyExc_EncodingWarning                       
     ' Part of the *note Stable ABI: 556. since
     version 3.10.'

 -- C Variable: *note PyObject: 33a.                   *note FutureWarning: 418.
          *PyExc_FutureWarning                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ImportWarning: 4fd.
          *PyExc_ImportWarning                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note PendingDeprecationWarning: 8d1.
          *PyExc_PendingDeprecationWarning             
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note ResourceWarning: 244.
          *PyExc_ResourceWarning                       
     ' Part of the *note Stable ABI: 556. since
     version 3.7.'

 -- C Variable: *note PyObject: 33a.                   *note RuntimeWarning: 1bd.
          *PyExc_RuntimeWarning                        
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note SyntaxWarning: 469.
          *PyExc_SyntaxWarning                         
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UnicodeWarning: 1472.
          *PyExc_UnicodeWarning                        
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyObject: 33a.                   *note UserWarning: 246d.
          *PyExc_UserWarning                           
     ' Part of the *note Stable ABI: 556.'

Added in version 3.2: *note PyExc_ResourceWarning: 4ccd.

Added in version 3.10: *note PyExc_EncodingWarning: 4cb1.


File: python.info,  Node: Tracebacks,  Prev: Exception and warning types,  Up: Exception Handling

7.5.11 Tracebacks
-----------------

 -- C Variable: *note PyTypeObject: aba. PyTraceBack_Type
     ' Part of the *note Stable ABI: 556.'  Type object for traceback
     objects.  This is available as *note types.TracebackType: b0b. in
     the Python layer.

 -- C Function: int PyTraceBack_Check (PyObject *op)

     Return true if 'op' is a traceback object, false otherwise.  This
     function does not account for subtypes.

 -- C Function: int PyTraceBack_Here (PyFrameObject *f)
     ' Part of the *note Stable ABI: 556.'  Replace the *note
     __traceback__: 130e. attribute on the current exception with a new
     traceback prepending 'f' to the existing chain.

     Calling this function without an exception set is undefined
     behavior.

     This function returns ‘0’ on success, and returns ‘-1’ with an
     exception set on failure.

 -- C Function: int PyTraceBack_Print (PyObject *tb, PyObject *f)
     ' Part of the *note Stable ABI: 556.'  Write the traceback 'tb'
     into the file 'f'.

     This function returns ‘0’ on success, and returns ‘-1’ with an
     exception set on failure.


File: python.info,  Node: Utilities<2>,  Next: Abstract Objects Layer,  Prev: Exception Handling,  Up: Python/C API Reference Manual

7.6 Utilities
=============

The functions in this chapter perform various utility tasks, ranging
from helping C code be more portable across platforms, using Python
modules from C, and parsing function arguments and constructing Python
values from C values.

* Menu:

* Operating System Utilities::
* System Functions::
* Process Control::
* Importing Modules: Importing Modules<2>.
* Data marshalling support::
* Parsing arguments and building values::
* String conversion and formatting::
* Character classification and conversion::
* PyHash API::
* Reflection::
* Codec registry and support functions::
* PyTime C API::
* Support for Perf Maps::


File: python.info,  Node: Operating System Utilities,  Next: System Functions,  Up: Utilities<2>

7.6.1 Operating System Utilities
--------------------------------

 -- C Function: *note PyObject: 33a. *PyOS_FSPath (PyObject *path)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.6.'  Return the file system representation for
     'path'.  If the object is a *note str: 44f. or *note bytes: 1c2.
     object, then a new *note strong reference: 33e. is returned.  If
     the object implements the *note os.PathLike: c72. interface, then
     *note __fspath__(): c73. is returned as long as it is a ‘str’ or
     ‘bytes’ object.  Otherwise *note TypeError: 2c3. is raised and
     ‘NULL’ is returned.

     Added in version 3.6.

 -- C Function: int Py_FdIsInteractive (FILE *fp, const char *filename)

     Return true (nonzero) if the standard I/O file 'fp' with name
     'filename' is deemed interactive.  This is the case for files for
     which ‘isatty(fileno(fp))’ is true.  If the *note
     PyConfig.interactive: 3d0. is non-zero, this function also returns
     true if the 'filename' pointer is ‘NULL’ or if the name is equal to
     one of the strings ‘'<stdin>'’ or ‘'???'’.

     This function must not be called before Python is initialized.

 -- C Function: void PyOS_BeforeFork ()
     ' Part of the *note Stable ABI: 556. on platforms with fork() since
     version 3.7.'  Function to prepare some internal state before a
     process fork.  This should be called before calling ‘fork()’ or any
     similar function that clones the current process.  Only available
     on systems where ‘fork()’ is defined.

          Warning: The C ‘fork()’ call should only be made from the
          *note “main” thread: 4ed1. (of the *note “main” interpreter:
          58a.).  The same is true for ‘PyOS_BeforeFork()’.

     Added in version 3.7.

 -- C Function: void PyOS_AfterFork_Parent ()
     ' Part of the *note Stable ABI: 556. on platforms with fork() since
     version 3.7.'  Function to update some internal state after a
     process fork.  This should be called from the parent process after
     calling ‘fork()’ or any similar function that clones the current
     process, regardless of whether process cloning was successful.
     Only available on systems where ‘fork()’ is defined.

          Warning: The C ‘fork()’ call should only be made from the
          *note “main” thread: 4ed1. (of the *note “main” interpreter:
          58a.).  The same is true for ‘PyOS_AfterFork_Parent()’.

     Added in version 3.7.

 -- C Function: void PyOS_AfterFork_Child ()
     ' Part of the *note Stable ABI: 556. on platforms with fork() since
     version 3.7.'  Function to update internal interpreter state after
     a process fork.  This must be called from the child process after
     calling ‘fork()’, or any similar function that clones the current
     process, if there is any chance the process will call back into the
     Python interpreter.  Only available on systems where ‘fork()’ is
     defined.

          Warning: The C ‘fork()’ call should only be made from the
          *note “main” thread: 4ed1. (of the *note “main” interpreter:
          58a.).  The same is true for ‘PyOS_AfterFork_Child()’.

     Added in version 3.7.

     See also
     ........

     *note os.register_at_fork(): 300. allows registering custom Python
     functions to be called by *note PyOS_BeforeFork(): bde, *note
     PyOS_AfterFork_Parent(): bdf. and *note PyOS_AfterFork_Child():
     3fe.

 -- C Function: void PyOS_AfterFork ()
     ' Part of the *note Stable ABI: 556. on platforms with fork().'
     Function to update some internal state after a process fork; this
     should be called in the new process if the Python interpreter will
     continue to be used.  If a new executable is loaded into the new
     process, this function does not need to be called.

     Deprecated since version 3.7: This function is superseded by *note
     PyOS_AfterFork_Child(): 3fe.

 -- C Function: int PyOS_CheckStack ()
     ' Part of the *note Stable ABI: 556. on platforms with
     USE_STACKCHECK since version 3.7.'

     Return true when the interpreter runs out of stack space.  This is
     a reliable check, but is only available when ‘USE_STACKCHECK’ is
     defined (currently on certain versions of Windows using the
     Microsoft Visual C++ compiler).  ‘USE_STACKCHECK’ will be defined
     automatically; you should never change the definition in your own
     code.

 -- C Type: typedef void (*PyOS_sighandler_t)(int)
     ' Part of the *note Stable ABI: 556.'

 -- C Function: *note PyOS_sighandler_t: 4d49. PyOS_getsig (int i)
     ' Part of the *note Stable ABI: 556.'  Return the current signal
     handler for signal 'i'.  This is a thin wrapper around either
     ‘sigaction()’ or ‘signal()’.  Do not call those functions directly!

 -- C Function: *note PyOS_sighandler_t: 4d49. PyOS_setsig (int i,
          PyOS_sighandler_t h)
     ' Part of the *note Stable ABI: 556.'  Set the signal handler for
     signal 'i' to be 'h'; return the old signal handler.  This is a
     thin wrapper around either ‘sigaction()’ or ‘signal()’.  Do not
     call those functions directly!

 -- C Function: int PyOS_InterruptOccurred (void)
     ' Part of the *note Stable ABI: 556.'  Check if a ‘SIGINT’ signal
     has been received.

     Returns ‘1’ if a ‘SIGINT’ has occurred and clears the signal flag,
     or ‘0’ otherwise.

     In most cases, you should prefer *note PyErr_CheckSignals(): 46a.
     over this function.  ‘PyErr_CheckSignals()’ invokes the appropriate
     signal handlers for all pending signals, allowing Python code to
     handle the signal properly.  This function only detects ‘SIGINT’
     and does not invoke any Python signal handlers.

     This function is async-signal-safe and this function cannot fail.
     The caller must hold an attached thread state.

 -- C Function: wchar_t *Py_DecodeLocale (const char *arg, size_t *size)
     ' Part of the *note Stable ABI: 556. since version 3.7.'
          Warning: This function should not be called directly: use the
          *note PyConfig: 3a9. API with the *note
          PyConfig_SetBytesString(): 9bf. function which ensures that
          *note Python is preinitialized: 3fa2.

          This function must not be called before *note Python is
          preinitialized: 3fa2. and so that the LC_CTYPE locale is
          properly configured: see the *note Py_PreInitialize(): 3ee.
          function.

     Decode a byte string from the *note filesystem encoding and error
     handler: 53e.  If the error handler is *note surrogateescape error
     handler: 259f, undecodable bytes are decoded as characters in range
     U+DC80..U+DCFF; and if a byte sequence can be decoded as a
     surrogate character, the bytes are escaped using the
     surrogateescape error handler instead of decoding them.

     Return a pointer to a newly allocated wide character string, use
     *note PyMem_RawFree(): 396. to free the memory.  If size is not
     ‘NULL’, write the number of wide characters excluding the null
     character into ‘*size’

     Return ‘NULL’ on decoding error or memory allocation error.  If
     'size' is not ‘NULL’, ‘*size’ is set to ‘(size_t)-1’ on memory
     error or set to ‘(size_t)-2’ on decoding error.

     The *note filesystem encoding and error handler: 53e. are selected
     by *note PyConfig_Read(): 793.: see *note filesystem_encoding: 3eb.
     and *note filesystem_errors: 3ec. members of *note PyConfig: 3a9.

     Decoding errors should never happen, unless there is a bug in the C
     library.

     Use the *note Py_EncodeLocale(): be7. function to encode the
     character string back to a byte string.

     See also
     ........

     The *note PyUnicode_DecodeFSDefaultAndSize(): 4dc7. and *note
     PyUnicode_DecodeLocaleAndSize(): be8. functions.

     Added in version 3.5.

     Changed in version 3.7: The function now uses the UTF-8 encoding in
     the *note Python UTF-8 Mode: 659.

     Changed in version 3.8: The function now uses the UTF-8 encoding on
     Windows if *note PyPreConfig.legacy_windows_fs_encoding: 3e9. is
     zero;

 -- C Function: char *Py_EncodeLocale (const wchar_t *text, size_t
          *error_pos)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Encode a
     wide character string to the *note filesystem encoding and error
     handler: 53e.  If the error handler is *note surrogateescape error
     handler: 259f, surrogate characters in the range U+DC80..U+DCFF are
     converted to bytes 0x80..0xFF.

     Return a pointer to a newly allocated byte string, use *note
     PyMem_Free(): 1491. to free the memory.  Return ‘NULL’ on encoding
     error or memory allocation error.

     If error_pos is not ‘NULL’, ‘*error_pos’ is set to ‘(size_t)-1’ on
     success, or set to the index of the invalid character on encoding
     error.

     The *note filesystem encoding and error handler: 53e. are selected
     by *note PyConfig_Read(): 793.: see *note filesystem_encoding: 3eb.
     and *note filesystem_errors: 3ec. members of *note PyConfig: 3a9.

     Use the *note Py_DecodeLocale(): be6. function to decode the bytes
     string back to a wide character string.

          Warning: This function must not be called before *note Python
          is preinitialized: 3fa2. and so that the LC_CTYPE locale is
          properly configured: see the *note Py_PreInitialize(): 3ee.
          function.

     See also
     ........

     The *note PyUnicode_EncodeFSDefault(): 1be2. and *note
     PyUnicode_EncodeLocale(): be9. functions.

     Added in version 3.5.

     Changed in version 3.7: The function now uses the UTF-8 encoding in
     the *note Python UTF-8 Mode: 659.

     Changed in version 3.8: The function now uses the UTF-8 encoding on
     Windows if *note PyPreConfig.legacy_windows_fs_encoding: 3e9. is
     zero.


File: python.info,  Node: System Functions,  Next: Process Control,  Prev: Operating System Utilities,  Up: Utilities<2>

7.6.2 System Functions
----------------------

These are utility functions that make functionality from the *note sys:
d9. module accessible to C code.  They all work with the current
interpreter thread’s ‘sys’ module’s dict, which is contained in the
internal thread state structure.

 -- C Function: *note PyObject: 33a. *PySys_GetObject (const char *name)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return the object 'name' from the *note sys: d9. module or
     ‘NULL’ if it does not exist, without setting an exception.

 -- C Function: int PySys_SetObject (const char *name, PyObject *v)
     ' Part of the *note Stable ABI: 556.'  Set 'name' in the *note sys:
     d9. module to 'v' unless 'v' is ‘NULL’, in which case 'name' is
     deleted from the sys module.  Returns ‘0’ on success, ‘-1’ on
     error.

 -- C Function: void PySys_ResetWarnOptions ()
     ' Part of the *note Stable ABI: 556.'  Reset *note sys.warnoptions:
     3b3. to an empty list.  This function may be called prior to *note
     Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15:
     Clear *note sys.warnoptions: 3b3. and ‘warnings.filters’ instead.

 -- C Function: void PySys_WriteStdout (const char *format, ...)
     ' Part of the *note Stable ABI: 556.'  Write the output string
     described by 'format' to *note sys.stdout: aec.  No exceptions are
     raised, even if truncation occurs (see below).

     'format' should limit the total size of the formatted output string
     to 1000 bytes or less – after 1000 bytes, the output string is
     truncated.  In particular, this means that no unrestricted “%s”
     formats should occur; these should be limited using “%.<N>s” where
     <N> is a decimal number calculated so that <N> plus the maximum
     size of other formatted text does not exceed 1000 bytes.  Also
     watch out for “%f”, which can print hundreds of digits for very
     large numbers.

     If a problem occurs, or *note sys.stdout: aec. is unset, the
     formatted message is written to the real (C level) 'stdout'.

 -- C Function: void PySys_WriteStderr (const char *format, ...)
     ' Part of the *note Stable ABI: 556.'  As *note
     PySys_WriteStdout(): 4d89, but write to *note sys.stderr: 943. or
     'stderr' instead.

 -- C Function: void PySys_FormatStdout (const char *format, ...)
     ' Part of the *note Stable ABI: 556.'  Function similar to
     PySys_WriteStdout() but format the message using *note
     PyUnicode_FromFormatV(): 577. and don’t truncate the message to an
     arbitrary length.

     Added in version 3.2.

 -- C Function: void PySys_FormatStderr (const char *format, ...)
     ' Part of the *note Stable ABI: 556.'  As *note
     PySys_FormatStdout(): 4d85, but write to *note sys.stderr: 943. or
     'stderr' instead.

     Added in version 3.2.

 -- C Function: *note PyObject: 33a. *PySys_GetXOptions ()
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.7.'  Return the current dictionary of *note
     -X: 176. options, similarly to *note sys._xoptions: 1ee7.  On
     error, ‘NULL’ is returned and an exception is set.

     Added in version 3.2.

 -- C Function: int PySys_Audit (const char *event, const char *format,
          ...)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Raise an
     auditing event with any active hooks.  Return zero for success and
     non-zero with an exception set on failure.

     The 'event' string argument must not be 'NULL'.

     If any hooks have been added, 'format' and other arguments will be
     used to construct a tuple to pass.  Apart from ‘N’, the same format
     characters as used in *note Py_BuildValue(): 8af. are available.
     If the built value is not a tuple, it will be added into a
     single-element tuple.

     The ‘N’ format option must not be used.  It consumes a reference,
     but since there is no way to know whether arguments to this
     function will be consumed, using it may cause reference leaks.

     Note that ‘#’ format characters should always be treated as *note
     Py_ssize_t: a6e, regardless of whether ‘PY_SSIZE_T_CLEAN’ was
     defined.

     *note sys.audit(): 16be. performs the same function from Python
     code.

     See also *note PySys_AuditTuple(): 371.

     Added in version 3.8.

     Changed in version 3.8.2: Require *note Py_ssize_t: a6e. for ‘#’
     format characters.  Previously, an unavoidable deprecation warning
     was raised.

 -- C Function: int PySys_AuditTuple (const char *event, PyObject *args)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note PySys_Audit(): 372, but pass arguments as a Python object.
     'args' must be a *note tuple: 373.  To pass no arguments, 'args'
     can be 'NULL'.

     Added in version 3.13.

 -- C Function: int PySys_AddAuditHook (Py_AuditHookFunction hook, void
          *userData)

     Append the callable 'hook' to the list of active auditing hooks.
     Return zero on success and non-zero on failure.  If the runtime has
     been initialized, also set an error on failure.  Hooks added
     through this API are called for all interpreters created by the
     runtime.

     The 'userData' pointer is passed into the hook function.  Since
     hook functions may be called from different runtimes, this pointer
     should not refer directly to Python state.

     This function is safe to call before *note Py_Initialize(): 8b4.
     When called after runtime initialization, existing audit hooks are
     notified and may silently abort the operation by raising an error
     subclassed from *note Exception: 9e5. (other errors will not be
     silenced).

     The hook function is always called with the GIL held by the Python
     interpreter that raised the event.

     See PEP 578(1) for a detailed description of auditing.  Functions
     in the runtime and standard library that raise events are listed in
     the *note audit events table: 19b7.  Details are in each function’s
     documentation.

     If the interpreter is initialized, this function raises an auditing
     event ‘sys.addaudithook’ with no arguments.  If any existing hooks
     raise an exception derived from *note Exception: 9e5, the new hook
     will not be added and the exception is cleared.  As a result,
     callers cannot assume that their hook has been added unless they
     control all existing hooks.

      -- C Type: typedef int (*Py_AuditHookFunction)(const char *event,
               *note PyObject: 33a. *args, void *userData)

          The type of the hook function.  'event' is the C string event
          argument passed to *note PySys_Audit(): 372. or *note
          PySys_AuditTuple(): 371.  'args' is guaranteed to be a *note
          PyTupleObject: 4ed5.  'userData' is the argument passed to
          PySys_AddAuditHook().

     Added in version 3.8.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0578/


File: python.info,  Node: Process Control,  Next: Importing Modules<2>,  Prev: System Functions,  Up: Utilities<2>

7.6.3 Process Control
---------------------

 -- C Function: void Py_FatalError (const char *message)
     ' Part of the *note Stable ABI: 556.'

     Print a fatal error message and kill the process.  No cleanup is
     performed.  This function should only be invoked when a condition
     is detected that would make it dangerous to continue using the
     Python interpreter; e.g., when the object administration appears to
     be corrupted.  On Unix, the standard C library function ‘abort()’
     is called which will attempt to produce a ‘core’ file.

     The ‘Py_FatalError()’ function is replaced with a macro which logs
     automatically the name of the current function, unless the
     ‘Py_LIMITED_API’ macro is defined.

     Changed in version 3.9: Log the function name automatically.

 -- C Function: void Py_Exit (int status)
     ' Part of the *note Stable ABI: 556.'

     Exit the current process.  This calls *note Py_FinalizeEx(): d3d.
     and then calls the standard C library function ‘exit(status)’.  If
     ‘Py_FinalizeEx()’ indicates an error, the exit status is set to
     120.

     Changed in version 3.6: Errors from finalization no longer ignored.

 -- C Function: int Py_AtExit (void (*func)())
     ' Part of the *note Stable ABI: 556.'

     Register a cleanup function to be called by *note Py_FinalizeEx():
     d3d.  The cleanup function will be called with no arguments and
     should return no value.  At most 32 cleanup functions can be
     registered.  When the registration is successful, *note
     Py_AtExit(): 4de8. returns ‘0’; on failure, it returns ‘-1’.  The
     cleanup function registered last is called first.  Each cleanup
     function will be called at most once.  Since Python’s internal
     finalization will have completed before the cleanup function, no
     Python APIs should be called by 'func'.

     See also
     ........

     *note PyUnstable_AtExit(): 1691. for passing a ‘void *data’
     argument.


File: python.info,  Node: Importing Modules<2>,  Next: Data marshalling support,  Prev: Process Control,  Up: Utilities<2>

7.6.4 Importing Modules
-----------------------

 -- C Function: *note PyObject: 33a. *PyImport_ImportModule (const char
          *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     This is a wrapper around *note PyImport_Import(): 144a. which takes
     a const char* as an argument instead of a *note PyObject: 33a.*.

 -- C Function: *note PyObject: 33a. *PyImport_ImportModuleNoBlock
          (const char *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This function is a deprecated alias of *note
     PyImport_ImportModule(): 3c1.

     Changed in version 3.3: This function used to fail immediately when
     the import lock was held by another thread.  In Python 3.3 though,
     the locking scheme switched to per-module locks for most purposes,
     so this function’s special behaviour isn’t needed anymore.

     Deprecated since version 3.13, will be removed in version 3.15: Use
     *note PyImport_ImportModule(): 3c1. instead.

 -- C Function: *note PyObject: 33a. *PyImport_ImportModuleEx (const
          char *name, PyObject *globals, PyObject *locals, PyObject
          *fromlist)
     'Return value: New reference.'

     Import a module.  This is best described by referring to the
     built-in Python function *note __import__(): 8dd.

     The return value is a new reference to the imported module or
     top-level package, or ‘NULL’ with an exception set on failure.
     Like for *note __import__(): 8dd, the return value when a submodule
     of a package was requested is normally the top-level package,
     unless a non-empty 'fromlist' was given.

     Failing imports remove incomplete module objects, like with *note
     PyImport_ImportModule(): 3c1.

 -- C Function: *note PyObject: 33a. *PyImport_ImportModuleLevelObject
          (PyObject *name, PyObject *globals, PyObject *locals, PyObject
          *fromlist, int level)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Import a module.  This is best described by
     referring to the built-in Python function *note __import__(): 8dd,
     as the standard ‘__import__()’ function calls this function
     directly.

     The return value is a new reference to the imported module or
     top-level package, or ‘NULL’ with an exception set on failure.
     Like for *note __import__(): 8dd, the return value when a submodule
     of a package was requested is normally the top-level package,
     unless a non-empty 'fromlist' was given.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyImport_ImportModuleLevel (const
          char *name, PyObject *globals, PyObject *locals, PyObject
          *fromlist, int level)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Similar to *note PyImport_ImportModuleLevelObject(): 4cfb,
     but the name is a UTF-8 encoded string instead of a Unicode object.

     Changed in version 3.3: Negative values for 'level' are no longer
     accepted.

 -- C Function: *note PyObject: 33a. *PyImport_Import (PyObject *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is a higher-level interface that calls the current
     “import hook function” (with an explicit 'level' of 0, meaning
     absolute import).  It invokes the *note __import__(): 8dd. function
     from the ‘__builtins__’ of the current globals.  This means that
     the import is done using whatever import hooks are installed in the
     current environment.

     This function always uses absolute imports.

 -- C Function: *note PyObject: 33a. *PyImport_ReloadModule (PyObject
          *m)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Reload a module.  Return a new reference to the reloaded
     module, or ‘NULL’ with an exception set on failure (the module
     still exists in this case).

 -- C Function: *note PyObject: 33a. *PyImport_AddModuleRef (const char
          *name)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.13.'  Return the module object corresponding to a
     module name.

     The 'name' argument may be of the form ‘package.module’.  First
     check the modules dictionary if there’s one there, and if not,
     create a new one and insert it in the modules dictionary.

     Return a *note strong reference: 33e. to the module on success.
     Return ‘NULL’ with an exception set on failure.

     The module name 'name' is decoded from UTF-8.

     This function does not load or import the module; if the module
     wasn’t already loaded, you will get an empty module object.  Use
     *note PyImport_ImportModule(): 3c1. or one of its variants to
     import a module.  Package structures implied by a dotted name for
     'name' are not created if not already present.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyImport_AddModuleObject (PyObject
          *name)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.7.'  Similar to *note PyImport_AddModuleRef():
     359, but return a *note borrowed reference: 33f. and 'name' is a
     Python *note str: 44f. object.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyImport_AddModule (const char
          *name)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Similar to *note PyImport_AddModuleRef(): 359, but return a
     *note borrowed reference: 33f.

 -- C Function: *note PyObject: 33a. *PyImport_ExecCodeModule (const
          char *name, PyObject *co)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Given a module name (possibly of the form ‘package.module’) and a
     code object read from a Python bytecode file or obtained from the
     built-in function *note compile(): 192, load the module.  Return a
     new reference to the module object, or ‘NULL’ with an exception set
     if an error occurred.  'name' is removed from *note sys.modules:
     1655. in error cases, even if 'name' was already in ‘sys.modules’
     on entry to *note PyImport_ExecCodeModule(): 4cf3.  Leaving
     incompletely initialized modules in ‘sys.modules’ is dangerous, as
     imports of such modules have no way to know that the module object
     is an unknown (and probably damaged with respect to the module
     author’s intents) state.

     The module’s *note __spec__: 20c6. and *note __loader__: 2e2. will
     be set, if not set already, with the appropriate values.  The
     spec’s loader will be set to the module’s ‘__loader__’ (if set) and
     to an instance of *note SourceFileLoader: 10b2. otherwise.

     The module’s *note __file__: 20cc. attribute will be set to the
     code object’s *note co_filename: 13ba.  If applicable, *note
     __cached__: 2d5. will also be set.

     This function will reload the module if it was already imported.
     See *note PyImport_ReloadModule(): 4cfc. for the intended way to
     reload a module.

     If 'name' points to a dotted name of the form ‘package.module’, any
     package structures not already created will still not be created.

     See also *note PyImport_ExecCodeModuleEx(): 4cf4. and *note
     PyImport_ExecCodeModuleWithPathnames(): 4cf6.

     Changed in version 3.12: The setting of *note __cached__: 2d5. and
     *note __loader__: 2e2. is deprecated.  See *note ModuleSpec: 200d.
     for alternatives.

 -- C Function: *note PyObject: 33a. *PyImport_ExecCodeModuleEx (const
          char *name, PyObject *co, const char *pathname)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Like *note PyImport_ExecCodeModule(): 4cf3, but the *note
     __file__: 20cc. attribute of the module object is set to 'pathname'
     if it is non-‘NULL’.

     See also *note PyImport_ExecCodeModuleWithPathnames(): 4cf6.

 -- C Function: *note PyObject: 33a. *PyImport_ExecCodeModuleObject
          (PyObject *name, PyObject *co, PyObject *pathname, PyObject
          *cpathname)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Like *note PyImport_ExecCodeModuleEx(): 4cf4,
     but the *note __cached__: 2d5. attribute of the module object is
     set to 'cpathname' if it is non-‘NULL’.  Of the three functions,
     this is the preferred one to use.

     Added in version 3.3.

     Changed in version 3.12: Setting *note __cached__: 2d5. is
     deprecated.  See *note ModuleSpec: 200d. for alternatives.

 -- C Function: *note PyObject: 33a.
          *PyImport_ExecCodeModuleWithPathnames (const char *name,
          PyObject *co, const char *pathname, const char *cpathname)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Like *note PyImport_ExecCodeModuleObject(): 4cf5, but
     'name', 'pathname' and 'cpathname' are UTF-8 encoded strings.
     Attempts are also made to figure out what the value for 'pathname'
     should be from 'cpathname' if the former is set to ‘NULL’.

     Added in version 3.2.

     Changed in version 3.3: Uses ‘imp.source_from_cache()’ in
     calculating the source path if only the bytecode path is provided.

     Changed in version 3.12: No longer uses the removed ‘imp’ module.

 -- C Function: long PyImport_GetMagicNumber ()
     ' Part of the *note Stable ABI: 556.'  Return the magic number for
     Python bytecode files (a.k.a.  ‘.pyc’ file).  The magic number
     should be present in the first four bytes of the bytecode file, in
     little-endian byte order.  Returns ‘-1’ on error.

     Changed in version 3.3: Return value of ‘-1’ upon failure.

 -- C Function: const char *PyImport_GetMagicTag ()
     ' Part of the *note Stable ABI: 556.'  Return the magic tag string
     for PEP 3147(1) format Python bytecode file names.  Keep in mind
     that the value at ‘sys.implementation.cache_tag’ is authoritative
     and should be used instead of this function.

     Added in version 3.2.

 -- C Function: *note PyObject: 33a. *PyImport_GetModuleDict ()
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return the dictionary used for the module administration
     (a.k.a.  ‘sys.modules’).  Note that this is a per-interpreter
     variable.

 -- C Function: *note PyObject: 33a. *PyImport_GetModule (PyObject
          *name)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.8.'  Return the already imported module with the
     given name.  If the module has not been imported yet then returns
     ‘NULL’ but does not set an error.  Returns ‘NULL’ and sets an error
     if the lookup failed.

     Added in version 3.7.

 -- C Function: *note PyObject: 33a. *PyImport_GetImporter (PyObject
          *path)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a finder object for a *note sys.path:
     3b7./‘pkg.__path__’ item 'path', possibly by fetching it from the
     *note sys.path_importer_cache: 5e7. dict.  If it wasn’t yet cached,
     traverse *note sys.path_hooks: 105f. until a hook is found that can
     handle the path item.  Return ‘None’ if no hook could; this tells
     our caller that the *note path based finder: 21ac. could not find a
     finder for this path item.  Cache the result in
     ‘sys.path_importer_cache’.  Return a new reference to the finder
     object.

 -- C Function: int PyImport_ImportFrozenModuleObject (PyObject *name)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Load a
     frozen module named 'name'.  Return ‘1’ for success, ‘0’ if the
     module is not found, and ‘-1’ with an exception set if the
     initialization failed.  To access the imported module on a
     successful load, use *note PyImport_ImportModule(): 3c1.  (Note the
     misnomer — this function would reload the module if it was already
     imported.)

     Added in version 3.3.

     Changed in version 3.4: The ‘__file__’ attribute is no longer set
     on the module.

 -- C Function: int PyImport_ImportFrozenModule (const char *name)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyImport_ImportFrozenModuleObject(): 4cfa, but the name is a UTF-8
     encoded string instead of a Unicode object.

 -- C Struct: struct _frozen

     This is the structure type definition for frozen module
     descriptors, as generated by the ‘freeze’ utility (see
     ‘Tools/freeze/’ in the Python source distribution).  Its
     definition, found in ‘Include/import.h’, is:

          struct _frozen {
              const char *name;
              const unsigned char *code;
              int size;
              bool is_package;
          };

     Changed in version 3.11: The new ‘is_package’ field indicates
     whether the module is a package or not.  This replaces setting the
     ‘size’ field to a negative value.

 -- C Variable: const struct *note _frozen: 778. *PyImport_FrozenModules

     This pointer is initialized to point to an array of *note _frozen:
     778. records, terminated by one whose members are all ‘NULL’ or
     zero.  When a frozen module is imported, it is searched in this
     table.  Third-party code could play tricks with this to provide a
     dynamically created collection of frozen modules.

 -- C Function: int PyImport_AppendInittab (const char *name, PyObject
          *(*initfunc)(void))
     ' Part of the *note Stable ABI: 556.'  Add a single module to the
     existing table of built-in modules.  This is a convenience wrapper
     around *note PyImport_ExtendInittab(): 18c0, returning ‘-1’ if the
     table could not be extended.  The new module can be imported by the
     name 'name', and uses the function 'initfunc' as the initialization
     function called on the first attempted import.  This should be
     called before *note Py_Initialize(): 8b4.

 -- C Struct: struct _inittab

     Structure describing a single entry in the list of built-in
     modules.  Programs which embed Python may use an array of these
     structures in conjunction with *note PyImport_ExtendInittab():
     18c0. to provide additional built-in modules.  The structure
     consists of two members:

      -- C Member: const char *name

          The module name, as an ASCII encoded string.

      -- C Member: *note PyObject: 33a. *(*initfunc)(void)

          Initialization function for a module built into the
          interpreter.

 -- C Function: int PyImport_ExtendInittab (struct _inittab *newtab)

     Add a collection of modules to the table of built-in modules.  The
     'newtab' array must end with a sentinel entry which contains ‘NULL’
     for the *note name: 4edd. field; failure to provide the sentinel
     value can result in a memory fault.  Returns ‘0’ on success or ‘-1’
     if insufficient memory could be allocated to extend the internal
     table.  In the event of failure, no modules are added to the
     internal table.  This must be called before *note Py_Initialize():
     8b4.

     If Python is initialized multiple times, *note
     PyImport_AppendInittab(): 18bf. or *note PyImport_ExtendInittab():
     18c0. must be called before each Python initialization.

 -- C Variable: struct *note _inittab: 4edc. *PyImport_Inittab

     The table of built-in modules used by Python initialization.  Do
     not use this directly; use *note PyImport_AppendInittab(): 18bf.
     and *note PyImport_ExtendInittab(): 18c0. instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: Data marshalling support,  Next: Parsing arguments and building values,  Prev: Importing Modules<2>,  Up: Utilities<2>

7.6.5 Data marshalling support
------------------------------

These routines allow C code to work with serialized objects using the
same data format as the *note marshal: 8d. module.  There are functions
to write data into the serialization format, and additional functions
that can be used to read the data back.  Files used to store marshalled
data must be opened in binary mode.

Numeric values are stored with the least significant byte first.

The module supports two versions of the data format: version 0 is the
historical version, version 1 shares interned strings in the file, and
upon unmarshalling.  Version 2 uses a binary format for floating-point
numbers.  ‘Py_MARSHAL_VERSION’ indicates the current file format
(currently 2).

 -- C Function: void PyMarshal_WriteLongToFile (long value, FILE *file,
          int version)

     Marshal a long integer, 'value', to 'file'.  This will only write
     the least-significant 32 bits of 'value'; regardless of the size of
     the native long type.  'version' indicates the file format.

     This function can fail, in which case it sets the error indicator.
     Use *note PyErr_Occurred(): 1a55. to check for that.

 -- C Function: void PyMarshal_WriteObjectToFile (PyObject *value, FILE
          *file, int version)

     Marshal a Python object, 'value', to 'file'.  'version' indicates
     the file format.

     This function can fail, in which case it sets the error indicator.
     Use *note PyErr_Occurred(): 1a55. to check for that.

 -- C Function: *note PyObject: 33a. *PyMarshal_WriteObjectToString
          (PyObject *value, int version)
     'Return value: New reference.'  Return a bytes object containing
     the marshalled representation of 'value'.  'version' indicates the
     file format.

The following functions allow marshalled values to be read back in.

 -- C Function: long PyMarshal_ReadLongFromFile (FILE *file)

     Return a C long from the data stream in a FILE* opened for reading.
     Only a 32-bit value can be read in using this function, regardless
     of the native size of long.

     On error, sets the appropriate exception (*note EOFError: 1321.)
     and returns ‘-1’.

 -- C Function: int PyMarshal_ReadShortFromFile (FILE *file)

     Return a C short from the data stream in a FILE* opened for
     reading.  Only a 16-bit value can be read in using this function,
     regardless of the native size of short.

     On error, sets the appropriate exception (*note EOFError: 1321.)
     and returns ‘-1’.

 -- C Function: *note PyObject: 33a. *PyMarshal_ReadObjectFromFile (FILE
          *file)
     'Return value: New reference.'  Return a Python object from the
     data stream in a FILE* opened for reading.

     On error, sets the appropriate exception (*note EOFError: 1321,
     *note ValueError: 202. or *note TypeError: 2c3.) and returns
     ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyMarshal_ReadLastObjectFromFile
          (FILE *file)
     'Return value: New reference.'  Return a Python object from the
     data stream in a FILE* opened for reading.  Unlike *note
     PyMarshal_ReadObjectFromFile(): 4ee5, this function assumes that no
     further objects will be read from the file, allowing it to
     aggressively load file data into memory so that the
     de-serialization can operate from data in memory rather than
     reading a byte at a time from the file.  Only use this variant if
     you are certain that you won’t be reading anything else from the
     file.

     On error, sets the appropriate exception (*note EOFError: 1321,
     *note ValueError: 202. or *note TypeError: 2c3.) and returns
     ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyMarshal_ReadObjectFromString
          (const char *data, Py_ssize_t len)
     'Return value: New reference.'  Return a Python object from the
     data stream in a byte buffer containing 'len' bytes pointed to by
     'data'.

     On error, sets the appropriate exception (*note EOFError: 1321,
     *note ValueError: 202. or *note TypeError: 2c3.) and returns
     ‘NULL’.


File: python.info,  Node: Parsing arguments and building values,  Next: String conversion and formatting,  Prev: Data marshalling support,  Up: Utilities<2>

7.6.6 Parsing arguments and building values
-------------------------------------------

These functions are useful when creating your own extension functions
and methods.  Additional information and examples are available in *note
Extending and Embedding the Python Interpreter: 1d6e.

The first three of these functions described, *note PyArg_ParseTuple():
574, *note PyArg_ParseTupleAndKeywords(): 386, and *note PyArg_Parse():
1b74, all use 'format strings' which are used to tell the function about
the expected arguments.  The format strings use the same syntax for each
of these functions.

* Menu:

* Parsing arguments: Parsing arguments<2>.
* Building values::


File: python.info,  Node: Parsing arguments<2>,  Next: Building values,  Up: Parsing arguments and building values

7.6.6.1 Parsing arguments
.........................

A format string consists of zero or more “format units.” A format unit
describes one Python object; it is usually a single character or a
parenthesized sequence of format units.  With a few exceptions, a format
unit that is not a parenthesized sequence normally corresponds to a
single address argument to these functions.  In the following
description, the quoted form is the format unit; the entry in (round)
parentheses is the Python object type that matches the format unit; and
the entry in [square] brackets is the type of the C variable(s) whose
address should be passed.

* Menu:

* Strings and buffers::
* Numbers: Numbers<2>.
* Other objects::
* API Functions::


File: python.info,  Node: Strings and buffers,  Next: Numbers<2>,  Up: Parsing arguments<2>

7.6.6.2 Strings and buffers
...........................

     Note: On Python 3.12 and older, the macro ‘PY_SSIZE_T_CLEAN’ must
     be defined before including ‘Python.h’ to use all ‘#’ variants of
     formats (‘s#’, ‘y#’, etc.)  explained below.  This is not necessary
     on Python 3.13 and later.

These formats allow accessing an object as a contiguous chunk of memory.
You don’t have to provide raw storage for the returned unicode or bytes
area.

Unless otherwise stated, buffers are not NUL-terminated.

There are three ways strings and buffers can be converted to C:

   * Formats such as ‘y*’ and ‘s*’ fill a *note Py_buffer: 75b.
     structure.  This locks the underlying buffer so that the caller can
     subsequently use the buffer even inside a *note
     Py_BEGIN_ALLOW_THREADS: 4b88. block without the risk of mutable
     data being resized or destroyed.  As a result, 'you have to call'
     *note PyBuffer_Release(): 39d. after you have finished processing
     the data (or in any early abort case).

   * The ‘es’, ‘es#’, ‘et’ and ‘et#’ formats allocate the result buffer.
     'You have to call' *note PyMem_Free(): 1491. after you have
     finished processing the data (or in any early abort case).

   * Other formats take a *note str: 44f. or a read-only *note
     bytes-like object: d55, such as *note bytes: 1c2, and provide a
     ‘const char *’ pointer to its buffer.  In this case the buffer is
     “borrowed”: it is managed by the corresponding Python object, and
     shares the lifetime of this object.  You won’t have to release any
     memory yourself.

     To ensure that the underlying buffer may be safely borrowed, the
     object’s *note PyBufferProcs.bf_releasebuffer: 766. field must be
     ‘NULL’.  This disallows common mutable objects such as *note
     bytearray: 2ea, but also some read-only objects such as *note
     memoryview: 2eb. of *note bytes: 1c2.

     Besides this ‘bf_releasebuffer’ requirement, there is no check to
     verify whether the input object is immutable (e.g.  whether it
     would honor a request for a writable buffer, or whether another
     thread can mutate the data).

‘s’ (*note str: 44f.) [const char *]

     Convert a Unicode object to a C pointer to a character string.  A
     pointer to an existing string is stored in the character pointer
     variable whose address you pass.  The C string is NUL-terminated.
     The Python string must not contain embedded null code points; if it
     does, a *note ValueError: 202. exception is raised.  Unicode
     objects are converted to C strings using ‘'utf-8'’ encoding.  If
     this conversion fails, a *note UnicodeError: 12eb. is raised.

          Note: This format does not accept *note bytes-like objects:
          d55.  If you want to accept filesystem paths and convert them
          to C character strings, it is preferable to use the ‘O&’
          format with *note PyUnicode_FSConverter(): d41. as
          'converter'.

     Changed in version 3.5: Previously, *note TypeError: 2c3. was
     raised when embedded null code points were encountered in the
     Python string.

‘s*’ (*note str: 44f. or *note bytes-like object: d55.) [Py_buffer]

     This format accepts Unicode objects as well as bytes-like objects.
     It fills a *note Py_buffer: 75b. structure provided by the caller.
     In this case the resulting C string may contain embedded NUL bytes.
     Unicode objects are converted to C strings using ‘'utf-8'’
     encoding.

‘s#’ (*note str: 44f, read-only *note bytes-like object: d55.) [const char *, *note Py_ssize_t: a6e.]

     Like ‘s*’, except that it provides a *note borrowed buffer: 4eec.
     The result is stored into two C variables, the first one a pointer
     to a C string, the second one its length.  The string may contain
     embedded null bytes.  Unicode objects are converted to C strings
     using ‘'utf-8'’ encoding.

‘z’ (*note str: 44f. or ‘None’) [const char *]

     Like ‘s’, but the Python object may also be ‘None’, in which case
     the C pointer is set to ‘NULL’.

‘z*’ (*note str: 44f, *note bytes-like object: d55. or ‘None’) [Py_buffer]

     Like ‘s*’, but the Python object may also be ‘None’, in which case
     the ‘buf’ member of the *note Py_buffer: 75b. structure is set to
     ‘NULL’.

‘z#’ (*note str: 44f, read-only *note bytes-like object: d55. or ‘None’) [const char *, *note Py_ssize_t: a6e.]

     Like ‘s#’, but the Python object may also be ‘None’, in which case
     the C pointer is set to ‘NULL’.

‘y’ (read-only *note bytes-like object: d55.) [const char *]

     This format converts a bytes-like object to a C pointer to a *note
     borrowed: 4eec. character string; it does not accept Unicode
     objects.  The bytes buffer must not contain embedded null bytes; if
     it does, a *note ValueError: 202. exception is raised.

     Changed in version 3.5: Previously, *note TypeError: 2c3. was
     raised when embedded null bytes were encountered in the bytes
     buffer.

‘y*’ (*note bytes-like object: d55.) [Py_buffer]

     This variant on ‘s*’ doesn’t accept Unicode objects, only
     bytes-like objects.  'This is the recommended way to accept binary
     data.'

‘y#’ (read-only *note bytes-like object: d55.) [const char *, *note Py_ssize_t: a6e.]

     This variant on ‘s#’ doesn’t accept Unicode objects, only
     bytes-like objects.

‘S’ (*note bytes: 1c2.) [PyBytesObject *]

     Requires that the Python object is a *note bytes: 1c2. object,
     without attempting any conversion.  Raises *note TypeError: 2c3. if
     the object is not a bytes object.  The C variable may also be
     declared as *note PyObject: 33a.*.

‘Y’ (*note bytearray: 2ea.) [PyByteArrayObject *]

     Requires that the Python object is a *note bytearray: 2ea. object,
     without attempting any conversion.  Raises *note TypeError: 2c3. if
     the object is not a ‘bytearray’ object.  The C variable may also be
     declared as *note PyObject: 33a.*.

‘U’ (*note str: 44f.) [PyObject *]

     Requires that the Python object is a Unicode object, without
     attempting any conversion.  Raises *note TypeError: 2c3. if the
     object is not a Unicode object.  The C variable may also be
     declared as *note PyObject: 33a.*.

‘w*’ (read-write *note bytes-like object: d55.) [Py_buffer]

     This format accepts any object which implements the read-write
     buffer interface.  It fills a *note Py_buffer: 75b. structure
     provided by the caller.  The buffer may contain embedded null
     bytes.  The caller has to call *note PyBuffer_Release(): 39d. when
     it is done with the buffer.

‘es’ (*note str: 44f.) [const char *encoding, char **buffer]

     This variant on ‘s’ is used for encoding Unicode into a character
     buffer.  It only works for encoded data without embedded NUL bytes.

     This format requires two arguments.  The first is only used as
     input, and must be a const char* which points to the name of an
     encoding as a NUL-terminated string, or ‘NULL’, in which case
     ‘'utf-8'’ encoding is used.  An exception is raised if the named
     encoding is not known to Python.  The second argument must be a
     char**; the value of the pointer it references will be set to a
     buffer with the contents of the argument text.  The text will be
     encoded in the encoding specified by the first argument.

     *note PyArg_ParseTuple(): 574. will allocate a buffer of the needed
     size, copy the encoded data into this buffer and adjust '*buffer'
     to reference the newly allocated storage.  The caller is
     responsible for calling *note PyMem_Free(): 1491. to free the
     allocated buffer after use.

‘et’ (*note str: 44f, *note bytes: 1c2. or *note bytearray: 2ea.) [const char *encoding, char **buffer]

     Same as ‘es’ except that byte string objects are passed through
     without recoding them.  Instead, the implementation assumes that
     the byte string object uses the encoding passed in as parameter.

‘es#’ (*note str: 44f.) [const char *encoding, char **buffer, *note Py_ssize_t: a6e. *buffer_length]

     This variant on ‘s#’ is used for encoding Unicode into a character
     buffer.  Unlike the ‘es’ format, this variant allows input data
     which contains NUL characters.

     It requires three arguments.  The first is only used as input, and
     must be a const char* which points to the name of an encoding as a
     NUL-terminated string, or ‘NULL’, in which case ‘'utf-8'’ encoding
     is used.  An exception is raised if the named encoding is not known
     to Python.  The second argument must be a char**; the value of the
     pointer it references will be set to a buffer with the contents of
     the argument text.  The text will be encoded in the encoding
     specified by the first argument.  The third argument must be a
     pointer to an integer; the referenced integer will be set to the
     number of bytes in the output buffer.

     There are two modes of operation:

     If '*buffer' points a ‘NULL’ pointer, the function will allocate a
     buffer of the needed size, copy the encoded data into this buffer
     and set '*buffer' to reference the newly allocated storage.  The
     caller is responsible for calling *note PyMem_Free(): 1491. to free
     the allocated buffer after usage.

     If '*buffer' points to a non-‘NULL’ pointer (an already allocated
     buffer), *note PyArg_ParseTuple(): 574. will use this location as
     the buffer and interpret the initial value of '*buffer_length' as
     the buffer size.  It will then copy the encoded data into the
     buffer and NUL-terminate it.  If the buffer is not large enough, a
     *note ValueError: 202. will be set.

     In both cases, '*buffer_length' is set to the length of the encoded
     data without the trailing NUL byte.

‘et#’ (*note str: 44f, *note bytes: 1c2. or *note bytearray: 2ea.) [const char *encoding, char **buffer, *note Py_ssize_t: a6e. *buffer_length]

     Same as ‘es#’ except that byte string objects are passed through
     without recoding them.  Instead, the implementation assumes that
     the byte string object uses the encoding passed in as parameter.

Changed in version 3.12: ‘u’, ‘u#’, ‘Z’, and ‘Z#’ are removed because
they used a legacy ‘Py_UNICODE*’ representation.


File: python.info,  Node: Numbers<2>,  Next: Other objects,  Prev: Strings and buffers,  Up: Parsing arguments<2>

7.6.6.3 Numbers
...............

These formats allow representing Python numbers or single characters as
C numbers.  Formats that require *note int: 257, *note float: 2f7. or
*note complex: 2f8. can also use the corresponding special methods *note
__index__(): 720, *note __float__(): 9d7. or *note __complex__(): 5ea.
to convert the Python object to the required type.

For signed integer formats, *note OverflowError: 888. is raised if the
value is out of range for the C type.  For unsigned integer formats, no
range checking is done — the most significant bits are silently
truncated when the receiving field is too small to receive the value.

‘b’ (*note int: 257.) [unsigned char]

     Convert a nonnegative Python integer to an unsigned tiny integer,
     stored in a C unsigned char.

‘B’ (*note int: 257.) [unsigned char]

     Convert a Python integer to a tiny integer without overflow
     checking, stored in a C unsigned char.

‘h’ (*note int: 257.) [short int]

     Convert a Python integer to a C short int.

‘H’ (*note int: 257.) [unsigned short int]

     Convert a Python integer to a C unsigned short int, without
     overflow checking.

‘i’ (*note int: 257.) [int]

     Convert a Python integer to a plain C int.

‘I’ (*note int: 257.) [unsigned int]

     Convert a Python integer to a C unsigned int, without overflow
     checking.

‘l’ (*note int: 257.) [long int]

     Convert a Python integer to a C long int.

‘k’ (*note int: 257.) [unsigned long]

     Convert a Python integer to a C unsigned long without overflow
     checking.

‘L’ (*note int: 257.) [long long]

     Convert a Python integer to a C long long.

‘K’ (*note int: 257.) [unsigned long long]

     Convert a Python integer to a C unsigned long long without overflow
     checking.

‘n’ (*note int: 257.) [*note Py_ssize_t: a6e.]

     Convert a Python integer to a C *note Py_ssize_t: a6e.

‘c’ (*note bytes: 1c2. or *note bytearray: 2ea. of length 1) [char]

     Convert a Python byte, represented as a *note bytes: 1c2. or *note
     bytearray: 2ea. object of length 1, to a C char.

     Changed in version 3.3: Allow *note bytearray: 2ea. objects.

‘C’ (*note str: 44f. of length 1) [int]

     Convert a Python character, represented as a *note str: 44f. object
     of length 1, to a C int.

‘f’ (*note float: 2f7.) [float]

     Convert a Python floating-point number to a C float.

‘d’ (*note float: 2f7.) [double]

     Convert a Python floating-point number to a C double.

‘D’ (*note complex: 2f8.) [Py_complex]

     Convert a Python complex number to a C *note Py_complex: 4eee.
     structure.


File: python.info,  Node: Other objects,  Next: API Functions,  Prev: Numbers<2>,  Up: Parsing arguments<2>

7.6.6.4 Other objects
.....................

‘O’ (object) [PyObject *]

     Store a Python object (without any conversion) in a C object
     pointer.  The C program thus receives the actual object that was
     passed.  A new *note strong reference: 33e. to the object is not
     created (i.e.  its reference count is not increased).  The pointer
     stored is not ‘NULL’.

‘O!’ (object) ['typeobject', PyObject *]

     Store a Python object in a C object pointer.  This is similar to
     ‘O’, but takes two C arguments: the first is the address of a
     Python type object, the second is the address of the C variable (of
     type *note PyObject: 33a.*) into which the object pointer is
     stored.  If the Python object does not have the required type,
     *note TypeError: 2c3. is raised.

‘O&’ (object) ['converter', 'address']

     Convert a Python object to a C variable through a 'converter'
     function.  This takes two arguments: the first is a function, the
     second is the address of a C variable (of arbitrary type),
     converted to void*.  The 'converter' function in turn is called as
     follows:

          status = converter(object, address);

     where 'object' is the Python object to be converted and 'address'
     is the void* argument that was passed to the ‘PyArg_Parse*’
     function.  The returned 'status' should be ‘1’ for a successful
     conversion and ‘0’ if the conversion has failed.  When the
     conversion fails, the 'converter' function should raise an
     exception and leave the content of 'address' unmodified.

     If the 'converter' returns ‘Py_CLEANUP_SUPPORTED’, it may get
     called a second time if the argument parsing eventually fails,
     giving the converter a chance to release any memory that it had
     already allocated.  In this second call, the 'object' parameter
     will be ‘NULL’; 'address' will have the same value as in the
     original call.

     Examples of converters: *note PyUnicode_FSConverter(): d41. and
     *note PyUnicode_FSDecoder(): 57a.

     Changed in version 3.1: ‘Py_CLEANUP_SUPPORTED’ was added.

‘p’ (*note bool: 46b.) [int]

     Tests the value passed in for truth (a boolean 'p'redicate) and
     converts the result to its equivalent C true/false integer value.
     Sets the int to ‘1’ if the expression was true and ‘0’ if it was
     false.  This accepts any valid Python value.  See *note Truth Value
     Testing: 164c. for more information about how Python tests values
     for truth.

     Added in version 3.3.

‘(items)’ (*note tuple: 373.) ['matching-items']

     The object must be a Python sequence whose length is the number of
     format units in 'items'.  The C arguments must correspond to the
     individual format units in 'items'.  Format units for sequences may
     be nested.

A few other characters have a meaning in a format string.  These may not
occur inside nested parentheses.  They are:

‘|’

     Indicates that the remaining arguments in the Python argument list
     are optional.  The C variables corresponding to optional arguments
     should be initialized to their default value — when an optional
     argument is not specified, *note PyArg_ParseTuple(): 574. does not
     touch the contents of the corresponding C variable(s).

‘$’

     *note PyArg_ParseTupleAndKeywords(): 386. only: Indicates that the
     remaining arguments in the Python argument list are keyword-only.
     Currently, all keyword-only arguments must also be optional
     arguments, so ‘|’ must always be specified before ‘$’ in the format
     string.

     Added in version 3.3.

‘:’

     The list of format units ends here; the string after the colon is
     used as the function name in error messages (the “associated value”
     of the exception that *note PyArg_ParseTuple(): 574. raises).

‘;’

     The list of format units ends here; the string after the semicolon
     is used as the error message 'instead' of the default error
     message.  ‘:’ and ‘;’ mutually exclude each other.

Note that any Python object references which are provided to the caller
are 'borrowed' references; do not release them (i.e.  do not decrement
their reference count)!

Additional arguments passed to these functions must be addresses of
variables whose type is determined by the format string; these are used
to store values from the input tuple.  There are a few cases, as
described in the list of format units above, where these parameters are
used as input values; they should match what is specified for the
corresponding format unit in that case.

For the conversion to succeed, the 'arg' object must match the format
and the format must be exhausted.  On success, the ‘PyArg_Parse*’
functions return true, otherwise they return false and raise an
appropriate exception.  When the ‘PyArg_Parse*’ functions fail due to
conversion failure in one of the format units, the variables at the
addresses corresponding to that and the following format units are left
untouched.


File: python.info,  Node: API Functions,  Prev: Other objects,  Up: Parsing arguments<2>

7.6.6.5 API Functions
.....................

 -- C Function: int PyArg_ParseTuple (PyObject *args, const char
          *format, ...)
     ' Part of the *note Stable ABI: 556.'  Parse the parameters of a
     function that takes only positional parameters into local
     variables.  Returns true on success; on failure, it returns false
     and raises the appropriate exception.

 -- C Function: int PyArg_VaParse (PyObject *args, const char *format,
          va_list vargs)
     ' Part of the *note Stable ABI: 556.'  Identical to *note
     PyArg_ParseTuple(): 574, except that it accepts a va_list rather
     than a variable number of arguments.

 -- C Function: int PyArg_ParseTupleAndKeywords (PyObject *args,
          PyObject *kw, const char *format, char *const *keywords, ...)
     ' Part of the *note Stable ABI: 556.'  Parse the parameters of a
     function that takes both positional and keyword parameters into
     local variables.  The 'keywords' argument is a ‘NULL’-terminated
     array of keyword parameter names specified as null-terminated ASCII
     or UTF-8 encoded C strings.  Empty names denote *note
     positional-only parameters: a94.  Returns true on success; on
     failure, it returns false and raises the appropriate exception.

          Note: The 'keywords' parameter declaration is char *const* in
          C and const char *const* in C++.  This can be overridden with
          the *note PY_CXX_CONST: 388. macro.

     Changed in version 3.6: Added support for *note positional-only
     parameters: a94.

     Changed in version 3.13: The 'keywords' parameter has now type char
     *const* in C and const char *const* in C++, instead of char**.
     Added support for non-ASCII keyword parameter names.

 -- C Function: int PyArg_VaParseTupleAndKeywords (PyObject *args,
          PyObject *kw, const char *format, char *const *keywords,
          va_list vargs)
     ' Part of the *note Stable ABI: 556.'  Identical to *note
     PyArg_ParseTupleAndKeywords(): 386, except that it accepts a
     va_list rather than a variable number of arguments.

 -- C Function: int PyArg_ValidateKeywordArguments (PyObject*)
     ' Part of the *note Stable ABI: 556.'  Ensure that the keys in the
     keywords argument dictionary are strings.  This is only needed if
     *note PyArg_ParseTupleAndKeywords(): 386. is not used, since the
     latter already does this check.

     Added in version 3.2.

 -- C Function: int PyArg_Parse (PyObject *args, const char *format,
          ...)
     ' Part of the *note Stable ABI: 556.'  Parse the parameter of a
     function that takes a single positional parameter into a local
     variable.  Returns true on success; on failure, it returns false
     and raises the appropriate exception.

     Example:

          // Function using METH_O calling convention
          static PyObject*
          my_function(PyObject *module, PyObject *arg)
          {
              int value;
              if (!PyArg_Parse(arg, "i:my_function", &value)) {
                  return NULL;
              }
              // ... use value ...
          }

 -- C Function: int PyArg_UnpackTuple (PyObject *args, const char *name,
          Py_ssize_t min, Py_ssize_t max, ...)
     ' Part of the *note Stable ABI: 556.'  A simpler form of parameter
     retrieval which does not use a format string to specify the types
     of the arguments.  Functions which use this method to retrieve
     their parameters should be declared as *note METH_VARARGS: 1558. in
     function or method tables.  The tuple containing the actual
     parameters should be passed as 'args'; it must actually be a tuple.
     The length of the tuple must be at least 'min' and no more than
     'max'; 'min' and 'max' may be equal.  Additional arguments must be
     passed to the function, each of which should be a pointer to a
     *note PyObject: 33a.* variable; these will be filled in with the
     values from 'args'; they will contain *note borrowed references:
     33f.  The variables which correspond to optional parameters not
     given by 'args' will not be filled in; these should be initialized
     by the caller.  This function returns true on success and false if
     'args' is not a tuple or contains the wrong number of elements; an
     exception will be set if there was a failure.

     This is an example of the use of this function, taken from the
     sources for the ‘_weakref’ helper module for weak references:

          static PyObject *
          weakref_ref(PyObject *self, PyObject *args)
          {
              PyObject *object;
              PyObject *callback = NULL;
              PyObject *result = NULL;

              if (PyArg_UnpackTuple(args, "ref", 1, 2, &object, &callback)) {
                  result = PyWeakref_NewRef(object, callback);
              }
              return result;
          }

     The call to *note PyArg_UnpackTuple(): 1556. in this example is
     entirely equivalent to this call to *note PyArg_ParseTuple(): 574.:

          PyArg_ParseTuple(args, "O|O:ref", &object, &callback)

 -- C Macro: PY_CXX_CONST

     The value to be inserted, if any, before char *const* in the
     'keywords' parameter declaration of *note
     PyArg_ParseTupleAndKeywords(): 386. and *note
     PyArg_VaParseTupleAndKeywords(): 387.  Default empty for C and
     ‘const’ for C++ (const char *const*).  To override, define it to
     the desired value before including ‘Python.h’.

     Added in version 3.13.


File: python.info,  Node: Building values,  Prev: Parsing arguments<2>,  Up: Parsing arguments and building values

7.6.6.6 Building values
.......................

 -- C Function: *note PyObject: 33a. *Py_BuildValue (const char *format,
          ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a new value based on a format string similar to those
     accepted by the ‘PyArg_Parse*’ family of functions and a sequence
     of values.  Returns the value or ‘NULL’ in the case of an error; an
     exception will be raised if ‘NULL’ is returned.

     *note Py_BuildValue(): 8af. does not always build a tuple.  It
     builds a tuple only if its format string contains two or more
     format units.  If the format string is empty, it returns ‘None’; if
     it contains exactly one format unit, it returns whatever object is
     described by that format unit.  To force it to return a tuple of
     size 0 or one, parenthesize the format string.

     When memory buffers are passed as parameters to supply data to
     build objects, as for the ‘s’ and ‘s#’ formats, the required data
     is copied.  Buffers provided by the caller are never referenced by
     the objects created by *note Py_BuildValue(): 8af.  In other words,
     if your code invokes ‘malloc()’ and passes the allocated memory to
     ‘Py_BuildValue()’, your code is responsible for calling ‘free()’
     for that memory once ‘Py_BuildValue()’ returns.

     In the following description, the quoted form is the format unit;
     the entry in (round) parentheses is the Python object type that the
     format unit will return; and the entry in [square] brackets is the
     type of the C value(s) to be passed.

     The characters space, tab, colon and comma are ignored in format
     strings (but not within format units such as ‘s#’).  This can be
     used to make long format strings a tad more readable.

     ‘s’ (*note str: 44f. or ‘None’) [const char *]

          Convert a null-terminated C string to a Python *note str: 44f.
          object using ‘'utf-8'’ encoding.  If the C string pointer is
          ‘NULL’, ‘None’ is used.

     ‘s#’ (*note str: 44f. or ‘None’) [const char *, *note Py_ssize_t: a6e.]

          Convert a C string and its length to a Python *note str: 44f.
          object using ‘'utf-8'’ encoding.  If the C string pointer is
          ‘NULL’, the length is ignored and ‘None’ is returned.

     ‘y’ (*note bytes: 1c2.) [const char *]

          This converts a C string to a Python *note bytes: 1c2. object.
          If the C string pointer is ‘NULL’, ‘None’ is returned.

     ‘y#’ (*note bytes: 1c2.) [const char *, *note Py_ssize_t: a6e.]

          This converts a C string and its lengths to a Python object.
          If the C string pointer is ‘NULL’, ‘None’ is returned.

     ‘z’ (*note str: 44f. or ‘None’) [const char *]

          Same as ‘s’.

     ‘z#’ (*note str: 44f. or ‘None’) [const char *, *note Py_ssize_t: a6e.]

          Same as ‘s#’.

     ‘u’ (*note str: 44f.) [const wchar_t *]

          Convert a null-terminated ‘wchar_t’ buffer of Unicode (UTF-16
          or UCS-4) data to a Python Unicode object.  If the Unicode
          buffer pointer is ‘NULL’, ‘None’ is returned.

     ‘u#’ (*note str: 44f.) [const wchar_t *, *note Py_ssize_t: a6e.]

          Convert a Unicode (UTF-16 or UCS-4) data buffer and its length
          to a Python Unicode object.  If the Unicode buffer pointer is
          ‘NULL’, the length is ignored and ‘None’ is returned.

     ‘U’ (*note str: 44f. or ‘None’) [const char *]

          Same as ‘s’.

     ‘U#’ (*note str: 44f. or ‘None’) [const char *, *note Py_ssize_t: a6e.]

          Same as ‘s#’.

     ‘i’ (*note int: 257.) [int]

          Convert a plain C int to a Python integer object.

     ‘b’ (*note int: 257.) [char]

          Convert a plain C char to a Python integer object.

     ‘h’ (*note int: 257.) [short int]

          Convert a plain C short int to a Python integer object.

     ‘l’ (*note int: 257.) [long int]

          Convert a C long int to a Python integer object.

     ‘B’ (*note int: 257.) [unsigned char]

          Convert a C unsigned char to a Python integer object.

     ‘H’ (*note int: 257.) [unsigned short int]

          Convert a C unsigned short int to a Python integer object.

     ‘I’ (*note int: 257.) [unsigned int]

          Convert a C unsigned int to a Python integer object.

     ‘k’ (*note int: 257.) [unsigned long]

          Convert a C unsigned long to a Python integer object.

     ‘L’ (*note int: 257.) [long long]

          Convert a C long long to a Python integer object.

     ‘K’ (*note int: 257.) [unsigned long long]

          Convert a C unsigned long long to a Python integer object.

     ‘n’ (*note int: 257.) [*note Py_ssize_t: a6e.]

          Convert a C *note Py_ssize_t: a6e. to a Python integer.

     ‘c’ (*note bytes: 1c2. of length 1) [char]

          Convert a C int representing a byte to a Python *note bytes:
          1c2. object of length 1.

     ‘C’ (*note str: 44f. of length 1) [int]

          Convert a C int representing a character to Python *note str:
          44f. object of length 1.

     ‘d’ (*note float: 2f7.) [double]

          Convert a C double to a Python floating-point number.

     ‘f’ (*note float: 2f7.) [float]

          Convert a C float to a Python floating-point number.

     ‘D’ (*note complex: 2f8.) [Py_complex *]

          Convert a C *note Py_complex: 4eee. structure to a Python
          complex number.

     ‘O’ (object) [PyObject *]

          Pass a Python object untouched but create a new *note strong
          reference: 33e. to it (i.e.  its reference count is
          incremented by one).  If the object passed in is a ‘NULL’
          pointer, it is assumed that this was caused because the call
          producing the argument found an error and set an exception.
          Therefore, *note Py_BuildValue(): 8af. will return ‘NULL’ but
          won’t raise an exception.  If no exception has been raised
          yet, *note SystemError: 578. is set.

     ‘S’ (object) [PyObject *]

          Same as ‘O’.

     ‘N’ (object) [PyObject *]

          Same as ‘O’, except it doesn’t create a new *note strong
          reference: 33e.  Useful when the object is created by a call
          to an object constructor in the argument list.

     ‘O&’ (object) ['converter', 'anything']

          Convert 'anything' to a Python object through a 'converter'
          function.  The function is called with 'anything' (which
          should be compatible with void*) as its argument and should
          return a “new” Python object, or ‘NULL’ if an error occurred.

     ‘(items)’ (*note tuple: 373.) ['matching-items']

          Convert a sequence of C values to a Python tuple with the same
          number of items.

     ‘[items]’ (*note list: 614.) ['matching-items']

          Convert a sequence of C values to a Python list with the same
          number of items.

     ‘{items}’ (*note dict: 256.) ['matching-items']

          Convert a sequence of C values to a Python dictionary.  Each
          pair of consecutive C values adds one item to the dictionary,
          serving as key and value, respectively.

     If there is an error in the format string, the *note SystemError:
     578. exception is set and ‘NULL’ returned.

 -- C Function: *note PyObject: 33a. *Py_VaBuildValue (const char
          *format, va_list vargs)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Identical to *note Py_BuildValue(): 8af, except that it
     accepts a va_list rather than a variable number of arguments.


File: python.info,  Node: String conversion and formatting,  Next: Character classification and conversion,  Prev: Parsing arguments and building values,  Up: Utilities<2>

7.6.7 String conversion and formatting
--------------------------------------

Functions for number conversion and formatted string output.

 -- C Function: int PyOS_snprintf (char *str, size_t size, const char
          *format, ...)
     ' Part of the *note Stable ABI: 556.'  Output not more than 'size'
     bytes to 'str' according to the format string 'format' and the
     extra arguments.  See the Unix man page ‘snprintf(3)(1)’.

 -- C Function: int PyOS_vsnprintf (char *str, size_t size, const char
          *format, va_list va)
     ' Part of the *note Stable ABI: 556.'  Output not more than 'size'
     bytes to 'str' according to the format string 'format' and the
     variable argument list 'va'.  Unix man page ‘vsnprintf(3)(2)’.

*note PyOS_snprintf(): 1559. and *note PyOS_vsnprintf(): 155a. wrap the
Standard C library functions ‘snprintf()’ and ‘vsnprintf()’.  Their
purpose is to guarantee consistent behavior in corner cases, which the
Standard C functions do not.

The wrappers ensure that ‘str[size-1]’ is always ‘'\0'’ upon return.
They never write more than 'size' bytes (including the trailing ‘'\0'’)
into str.  Both functions require that ‘str != NULL’, ‘size > 0’,
‘format != NULL’ and ‘size < INT_MAX’.  Note that this means there is no
equivalent to the C99 ‘n = snprintf(NULL, 0, ...)’ which would determine
the necessary buffer size.

The return value ('rv') for these functions should be interpreted as
follows:

   * When ‘0 <= rv < size’, the output conversion was successful and
     'rv' characters were written to 'str' (excluding the trailing
     ‘'\0'’ byte at ‘str[rv]’).

   * When ‘rv >= size’, the output conversion was truncated and a buffer
     with ‘rv + 1’ bytes would have been needed to succeed.
     ‘str[size-1]’ is ‘'\0'’ in this case.

   * When ‘rv < 0’, the output conversion failed and ‘str[size-1]’ is
     ‘'\0'’ in this case too, but the rest of 'str' is undefined.  The
     exact cause of the error depends on the underlying platform.

The following functions provide locale-independent string to number
conversions.

 -- C Function: unsigned long PyOS_strtoul (const char *str, char **ptr,
          int base)
     ' Part of the *note Stable ABI: 556.'  Convert the initial part of
     the string in ‘str’ to an unsigned long value according to the
     given ‘base’, which must be between ‘2’ and ‘36’ inclusive, or be
     the special value ‘0’.

     Leading white space and case of characters are ignored.  If ‘base’
     is zero it looks for a leading ‘0b’, ‘0o’ or ‘0x’ to tell which
     base.  If these are absent it defaults to ‘10’.  Base must be 0 or
     between 2 and 36 (inclusive).  If ‘ptr’ is non-‘NULL’ it will
     contain a pointer to the end of the scan.

     If the converted value falls out of range of corresponding return
     type, range error occurs (‘errno’ is set to ‘ERANGE’) and
     ‘ULONG_MAX’ is returned.  If no conversion can be performed, ‘0’ is
     returned.

     See also the Unix man page ‘strtoul(3)(3)’.

     Added in version 3.2.

 -- C Function: long PyOS_strtol (const char *str, char **ptr, int base)
     ' Part of the *note Stable ABI: 556.'  Convert the initial part of
     the string in ‘str’ to an long value according to the given ‘base’,
     which must be between ‘2’ and ‘36’ inclusive, or be the special
     value ‘0’.

     Same as *note PyOS_strtoul(): 4d4b, but return a long value instead
     and ‘LONG_MAX’ on overflows.

     See also the Unix man page ‘strtol(3)(4)’.

     Added in version 3.2.

 -- C Function: double PyOS_string_to_double (const char *s, char
          **endptr, PyObject *overflow_exception)
     ' Part of the *note Stable ABI: 556.'  Convert a string ‘s’ to a
     double, raising a Python exception on failure.  The set of accepted
     strings corresponds to the set of strings accepted by Python’s
     *note float(): 2f7. constructor, except that ‘s’ must not have
     leading or trailing whitespace.  The conversion is independent of
     the current locale.

     If ‘endptr’ is ‘NULL’, convert the whole string.  Raise *note
     ValueError: 202. and return ‘-1.0’ if the string is not a valid
     representation of a floating-point number.

     If endptr is not ‘NULL’, convert as much of the string as possible
     and set ‘*endptr’ to point to the first unconverted character.  If
     no initial segment of the string is the valid representation of a
     floating-point number, set ‘*endptr’ to point to the beginning of
     the string, raise ValueError, and return ‘-1.0’.

     If ‘s’ represents a value that is too large to store in a float
     (for example, ‘"1e500"’ is such a string on many platforms) then if
     ‘overflow_exception’ is ‘NULL’ return ‘Py_HUGE_VAL’ (with an
     appropriate sign) and don’t set any exception.  Otherwise,
     ‘overflow_exception’ must point to a Python exception object; raise
     that exception and return ‘-1.0’.  In both cases, set ‘*endptr’ to
     point to the first character after the converted value.

     If any other error occurs during the conversion (for example an
     out-of-memory error), set the appropriate Python exception and
     return ‘-1.0’.

     Added in version 3.1.

 -- C Function: char *PyOS_double_to_string (double val, char
          format_code, int precision, int flags, int *ptype)
     ' Part of the *note Stable ABI: 556.'  Convert a double 'val' to a
     string using supplied 'format_code', 'precision', and 'flags'.

     'format_code' must be one of ‘'e'’, ‘'E'’, ‘'f'’, ‘'F'’, ‘'g'’,
     ‘'G'’ or ‘'r'’.  For ‘'r'’, the supplied 'precision' must be 0 and
     is ignored.  The ‘'r'’ format code specifies the standard *note
     repr(): 803. format.

     'flags' can be zero or more of the following values or-ed together:

      -- C Macro: Py_DTSF_SIGN

          Always precede the returned string with a sign character, even
          if 'val' is non-negative.

      -- C Macro: Py_DTSF_ADD_DOT_0

          Ensure that the returned string will not look like an integer.

      -- C Macro: Py_DTSF_ALT

          Apply “alternate” formatting rules.  See the documentation for
          the *note PyOS_snprintf(): 1559. ‘'#'’ specifier for details.

      -- C Macro: Py_DTSF_NO_NEG_0

          Negative zero is converted to positive zero.

          Added in version 3.11.

     If 'ptype' is non-‘NULL’, then the value it points to will be set
     to one of the following constants depending on the type of 'val':

     '*ptype'                                               type of 'val'
                                                            
     --------------------------------------------------------------------------------------------------------------
                                                            
      -- C Macro: Py_DTST_FINITE                            finite number
                                                            
                                                            
      -- C Macro: Py_DTST_INFINITE                          infinite number
                                                            
                                                            
      -- C Macro: Py_DTST_NAN                               not a number
                                                            

     The return value is a pointer to 'buffer' with the converted string
     or ‘NULL’ if the conversion failed.  The caller is responsible for
     freeing the returned string by calling *note PyMem_Free(): 1491.

     Added in version 3.1.

 -- C Function: int PyOS_mystricmp (const char *str1, const char *str2)
 -- C Function: int PyOS_mystrnicmp (const char *str1, const char *str2,
          Py_ssize_t size)
     ' Part of the *note Stable ABI: 556.'  Case insensitive comparison
     of strings.  These functions work almost identically to ‘strcmp()’
     and ‘strncmp()’ (respectively), except that they ignore the case of
     ASCII characters.

     Return ‘0’ if the strings are equal, a negative value if 'str1'
     sorts lexicographically before 'str2', or a positive value if it
     sorts after.

     In the 'str1' or 'str2' arguments, a NUL byte marks the end of the
     string.  For ‘PyOS_mystrnicmp()’, the 'size' argument gives the
     maximum size of the string, as if NUL was present at the index
     given by 'size'.

     These functions do not use the locale.

 -- C Function: int PyOS_stricmp (const char *str1, const char *str2)
 -- C Function: int PyOS_strnicmp (const char *str1, const char *str2,
          Py_ssize_t size)

     Case insensitive comparison of strings.

     On Windows, these are aliases of ‘stricmp()’ and ‘strnicmp()’,
     respectively.

     On other platforms, they are aliases of *note PyOS_mystricmp():
     1ae2. and *note PyOS_mystrnicmp(): 1ae1, respectively.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/snprintf(3)

   (2) https://manpages.debian.org/vsnprintf(3)

   (3) https://manpages.debian.org/strtoul(3)

   (4) https://manpages.debian.org/strtol(3)


File: python.info,  Node: Character classification and conversion,  Next: PyHash API,  Prev: String conversion and formatting,  Up: Utilities<2>

7.6.8 Character classification and conversion
---------------------------------------------

The following macros provide locale-independent (unlike the C standard
library ‘ctype.h’) character classification and conversion.  The
argument must be a signed or unsigned char.

 -- C Macro: Py_ISALNUM (c)

     Return true if the character 'c' is an alphanumeric character.

 -- C Macro: Py_ISALPHA (c)

     Return true if the character 'c' is an alphabetic character (‘a-z’
     and ‘A-Z’).

 -- C Macro: Py_ISDIGIT (c)

     Return true if the character 'c' is a decimal digit (‘0-9’).

 -- C Macro: Py_ISLOWER (c)

     Return true if the character 'c' is a lowercase ASCII letter
     (‘a-z’).

 -- C Macro: Py_ISUPPER (c)

     Return true if the character 'c' is an uppercase ASCII letter
     (‘A-Z’).

 -- C Macro: Py_ISSPACE (c)

     Return true if the character 'c' is a whitespace character (space,
     tab, carriage return, newline, vertical tab, or form feed).

 -- C Macro: Py_ISXDIGIT (c)

     Return true if the character 'c' is a hexadecimal digit (‘0-9’,
     ‘a-f’, and ‘A-F’).

 -- C Macro: Py_TOLOWER (c)

     Return the lowercase equivalent of the character 'c'.

 -- C Macro: Py_TOUPPER (c)

     Return the uppercase equivalent of the character 'c'.


File: python.info,  Node: PyHash API,  Next: Reflection,  Prev: Character classification and conversion,  Up: Utilities<2>

7.6.9 PyHash API
----------------

See also the *note PyTypeObject.tp_hash: 4bc0. member and *note Hashing
of numeric types: 2358.

 -- C Type: type Py_hash_t

     Hash value type: signed integer.

     Added in version 3.2.

 -- C Type: type Py_uhash_t

     Hash value type: unsigned integer.

     Added in version 3.2.

 -- C Macro: Py_HASH_ALGORITHM

     A numerical value indicating the algorithm for hashing of *note
     str: 44f, *note bytes: 1c2, and *note memoryview: 2eb.

     The algorithm name is exposed by *note sys.hash_info.algorithm:
     45e3.

     Added in version 3.4.

 -- C Macro: Py_HASH_FNV
 -- C Macro: Py_HASH_SIPHASH24
 -- C Macro: Py_HASH_SIPHASH13

     Numerical values to compare to *note Py_HASH_ALGORITHM: 4f06. to
     determine which algorithm is used for hashing.  The hash algorithm
     can be configured via the configure *note -with-hash-algorithm:
     1f6a. option.

     Added in version 3.4: Add ‘Py_HASH_FNV’ and ‘Py_HASH_SIPHASH24’.

     Added in version 3.11: Add ‘Py_HASH_SIPHASH13’.

 -- C Macro: Py_HASH_CUTOFF

     Buffers of length in range ‘[1, Py_HASH_CUTOFF)’ are hashed using
     DJBX33A instead of the algorithm described by *note
     Py_HASH_ALGORITHM: 4f06.

        - A ‘Py_HASH_CUTOFF’ of 0 disables the optimization.

        - ‘Py_HASH_CUTOFF’ must be non-negative and less or equal than
          7.

     32-bit platforms should use a cutoff smaller than 64-bit platforms
     because it is easier to create colliding strings.  A cutoff of 7 on
     64-bit platforms and 5 on 32-bit platforms should provide a decent
     safety margin.

     This corresponds to the *note sys.hash_info.cutoff: 45e6. constant.

     Added in version 3.4.

 -- C Macro: PyHASH_MODULUS

     The Mersenne prime(1) ‘P = 2**n -1’, used for numeric hash scheme.

     This corresponds to the *note sys.hash_info.modulus: 2359.
     constant.

     Added in version 3.13.

 -- C Macro: PyHASH_BITS

     The exponent ‘n’ of ‘P’ in *note PyHASH_MODULUS: 177c.

     Added in version 3.13.

 -- C Macro: PyHASH_MULTIPLIER

     Prime multiplier used in string and various other hashes.

     Added in version 3.13.

 -- C Macro: PyHASH_INF

     The hash value returned for a positive infinity.

     This corresponds to the *note sys.hash_info.inf: 45e0. constant.

     Added in version 3.13.

 -- C Macro: PyHASH_IMAG

     The multiplier used for the imaginary part of a complex number.

     This corresponds to the *note sys.hash_info.imag: 45e2. constant.

     Added in version 3.13.

 -- C Type: type PyHash_FuncDef

     Hash function definition used by *note PyHash_GetFuncDef(): 4f0c.

      -- C Member: *note Py_hash_t: 12aa. (*const hash)(const void*,
               *note Py_ssize_t: a6e.)

          Hash function.

      -- C Member: const char *name

          Hash function name (UTF-8 encoded string).

          This corresponds to the *note sys.hash_info.algorithm: 45e3.
          constant.

      -- C Member: const int hash_bits

          Internal size of the hash value in bits.

          This corresponds to the *note sys.hash_info.hash_bits: 45e4.
          constant.

      -- C Member: const int seed_bits

          Size of seed input in bits.

          This corresponds to the *note sys.hash_info.seed_bits: 45e5.
          constant.

     Added in version 3.4.

 -- C Function: *note PyHash_FuncDef: 4f0b. *PyHash_GetFuncDef (void)

     Get the hash function definition.

     See also
     ........

     PEP 456(2) “Secure and interchangeable hash algorithm”.

     Added in version 3.4.

 -- C Function: *note Py_hash_t: 12aa. Py_HashPointer (const void *ptr)

     Hash a pointer value: process the pointer value as an integer (cast
     it to ‘uintptr_t’ internally).  The pointer is not dereferenced.

     The function cannot fail: it cannot return ‘-1’.

     Added in version 3.13.

 -- C Function: *note Py_hash_t: 12aa. PyObject_GenericHash (PyObject
          *obj)

     Generic hashing function that is meant to be put into a type
     object’s ‘tp_hash’ slot.  Its result only depends on the object’s
     identity.

     'CPython implementation detail:' In CPython, it is equivalent to
     *note Py_HashPointer(): 36b.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Mersenne_prime

   (2) https://peps.python.org/pep-0456/


File: python.info,  Node: Reflection,  Next: Codec registry and support functions,  Prev: PyHash API,  Up: Utilities<2>

7.6.10 Reflection
-----------------

 -- C Function: *note PyObject: 33a. *PyEval_GetBuiltins (void)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'

     Deprecated since version 3.13: Use *note PyEval_GetFrameBuiltins():
     351. instead.

     Return a dictionary of the builtins in the current execution frame,
     or the interpreter of the thread state if no frame is currently
     executing.

 -- C Function: *note PyObject: 33a. *PyEval_GetLocals (void)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'

     Deprecated since version 3.13: Use either *note
     PyEval_GetFrameLocals(): 355. to obtain the same behaviour as
     calling *note locals(): 141. in Python code, or else call *note
     PyFrame_GetLocals(): 422. on the result of *note PyEval_GetFrame():
     18dc. to access the *note f_locals: 182. attribute of the currently
     executing frame.

     Return a mapping providing access to the local variables in the
     current execution frame, or ‘NULL’ if no frame is currently
     executing.

     Refer to *note locals(): 141. for details of the mapping returned
     at different scopes.

     As this function returns a *note borrowed reference: 33f, the
     dictionary returned for *note optimized scopes: 17e. is cached on
     the frame object and will remain alive as long as the frame object
     does.  Unlike *note PyEval_GetFrameLocals(): 355. and *note
     locals(): 141, subsequent calls to this function in the same frame
     will update the contents of the cached dictionary to reflect
     changes in the state of the local variables rather than returning a
     new snapshot.

     Changed in version 3.13: As part of PEP 667(1), *note
     PyFrame_GetLocals(): 422, *note locals(): 141, and *note
     FrameType.f_locals: 182. no longer make use of the shared cache
     dictionary.  Refer to the *note What’s New entry: 142. for
     additional details.

 -- C Function: *note PyObject: 33a. *PyEval_GetGlobals (void)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'

     Deprecated since version 3.13: Use *note PyEval_GetFrameGlobals():
     353. instead.

     Return a dictionary of the global variables in the current
     execution frame, or ‘NULL’ if no frame is currently executing.

 -- C Function: *note PyFrameObject: 78c. *PyEval_GetFrame (void)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return the current thread state’s frame, which is ‘NULL’ if
     no frame is currently executing.

     See also *note PyThreadState_GetFrame(): 791.

 -- C Function: *note PyObject: 33a. *PyEval_GetFrameBuiltins (void)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.13.'  Return a dictionary of the builtins in the
     current execution frame, or the interpreter of the thread state if
     no frame is currently executing.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyEval_GetFrameLocals (void)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.13.'  Return a dictionary of the local variables in
     the current execution frame, or ‘NULL’ if no frame is currently
     executing.  Equivalent to calling *note locals(): 141. in Python
     code.

     To access *note f_locals: 182. on the current frame without making
     an independent snapshot in *note optimized scopes: 17e, call *note
     PyFrame_GetLocals(): 422. on the result of *note PyEval_GetFrame():
     18dc.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyEval_GetFrameGlobals (void)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.13.'  Return a dictionary of the global variables
     in the current execution frame, or ‘NULL’ if no frame is currently
     executing.  Equivalent to calling *note globals(): 19ae. in Python
     code.

     Added in version 3.13.

 -- C Function: const char *PyEval_GetFuncName (PyObject *func)
     ' Part of the *note Stable ABI: 556.'  Return the name of 'func' if
     it is a function, class or instance object, else the name of
     'func's type.

 -- C Function: const char *PyEval_GetFuncDesc (PyObject *func)
     ' Part of the *note Stable ABI: 556.'  Return a description string,
     depending on the type of 'func'.  Return values include “()” for
     functions and methods, “ constructor”, “ instance”, and “ object”.
     Concatenated with the result of *note PyEval_GetFuncName(): 4c9f,
     the result will be a description of 'func'.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/


File: python.info,  Node: Codec registry and support functions,  Next: PyTime C API,  Prev: Reflection,  Up: Utilities<2>

7.6.11 Codec registry and support functions
-------------------------------------------

 -- C Function: int PyCodec_Register (PyObject *search_function)
     ' Part of the *note Stable ABI: 556.'  Register a new codec search
     function.

     As a side effect, this tries to load the ‘encodings’ package, if
     not yet done, to make sure that it is always first in the list of
     search functions.

 -- C Function: int PyCodec_Unregister (PyObject *search_function)
     ' Part of the *note Stable ABI: 556. since version 3.10.'
     Unregister a codec search function and clear the registry’s cache.
     If the search function is not registered, do nothing.  Return 0 on
     success.  Raise an exception and return -1 on error.

     Added in version 3.10.

 -- C Function: int PyCodec_KnownEncoding (const char *encoding)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ or ‘0’ depending
     on whether there is a registered codec for the given 'encoding'.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyCodec_Encode (PyObject *object,
          const char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Generic codec based encoding API.

     'object' is passed through the encoder function found for the given
     'encoding' using the error handling method defined by 'errors'.
     'errors' may be ‘NULL’ to use the default method defined for the
     codec.  Raises a *note LookupError: 238a. if no encoder can be
     found.

 -- C Function: *note PyObject: 33a. *PyCodec_Decode (PyObject *object,
          const char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Generic codec based decoding API.

     'object' is passed through the decoder function found for the given
     'encoding' using the error handling method defined by 'errors'.
     'errors' may be ‘NULL’ to use the default method defined for the
     codec.  Raises a *note LookupError: 238a. if no decoder can be
     found.

* Menu:

* Codec lookup API::
* Registry API for Unicode encoding error handlers::
* Codec utility variables::


File: python.info,  Node: Codec lookup API,  Next: Registry API for Unicode encoding error handlers,  Up: Codec registry and support functions

7.6.11.1 Codec lookup API
.........................

In the following functions, the 'encoding' string is looked up converted
to all lower-case characters, which makes encodings looked up through
this mechanism effectively case-insensitive.  If no codec is found, a
*note KeyError: 345. is set and ‘NULL’ returned.

 -- C Function: *note PyObject: 33a. *PyCodec_Encoder (const char
          *encoding)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get an encoder function for the given 'encoding'.

 -- C Function: *note PyObject: 33a. *PyCodec_Decoder (const char
          *encoding)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get a decoder function for the given 'encoding'.

 -- C Function: *note PyObject: 33a. *PyCodec_IncrementalEncoder (const
          char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get an *note IncrementalEncoder: 2582. object for the given
     'encoding'.

 -- C Function: *note PyObject: 33a. *PyCodec_IncrementalDecoder (const
          char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get an *note IncrementalDecoder: 2583. object for the given
     'encoding'.

 -- C Function: *note PyObject: 33a. *PyCodec_StreamReader (const char
          *encoding, PyObject *stream, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get a *note StreamReader: 2587. factory function for the
     given 'encoding'.

 -- C Function: *note PyObject: 33a. *PyCodec_StreamWriter (const char
          *encoding, PyObject *stream, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Get a *note StreamWriter: 2586. factory function for the
     given 'encoding'.


File: python.info,  Node: Registry API for Unicode encoding error handlers,  Next: Codec utility variables,  Prev: Codec lookup API,  Up: Codec registry and support functions

7.6.11.2 Registry API for Unicode encoding error handlers
.........................................................

 -- C Function: int PyCodec_RegisterError (const char *name, PyObject
          *error)
     ' Part of the *note Stable ABI: 556.'  Register the error handling
     callback function 'error' under the given 'name'.  This callback
     function will be called by a codec when it encounters unencodable
     characters/undecodable bytes and 'name' is specified as the error
     parameter in the call to the encode/decode function.

     The callback gets a single argument, an instance of *note
     UnicodeEncodeError: 67a, *note UnicodeDecodeError: a20. or *note
     UnicodeTranslateError: 2456. that holds information about the
     problematic sequence of characters or bytes and their offset in the
     original string (see *note Unicode Exception Objects: 4ebd. for
     functions to extract this information).  The callback must either
     raise the given exception, or return a two-item tuple containing
     the replacement for the problematic sequence, and an integer giving
     the offset in the original string at which encoding/decoding should
     be resumed.

     Return ‘0’ on success, ‘-1’ on error.

 -- C Function: *note PyObject: 33a. *PyCodec_LookupError (const char
          *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Lookup the error handling callback function registered under
     'name'.  As a special case ‘NULL’ can be passed, in which case the
     error handling callback for “strict” will be returned.

 -- C Function: *note PyObject: 33a. *PyCodec_StrictErrors (PyObject
          *exc)
     'Return value: Always NULL.'' Part of the *note Stable ABI: 556.'
     Raise 'exc' as an exception.

 -- C Function: *note PyObject: 33a. *PyCodec_IgnoreErrors (PyObject
          *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Ignore the unicode error, skipping the faulty input.

 -- C Function: *note PyObject: 33a. *PyCodec_ReplaceErrors (PyObject
          *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Replace the unicode encode error with ‘?’ or ‘U+FFFD’.

 -- C Function: *note PyObject: 33a. *PyCodec_XMLCharRefReplaceErrors
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Replace the unicode encode error with XML character
     references.

 -- C Function: *note PyObject: 33a. *PyCodec_BackslashReplaceErrors
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Replace the unicode encode error with backslash escapes
     (‘\x’, ‘\u’ and ‘\U’).

 -- C Function: *note PyObject: 33a. *PyCodec_NameReplaceErrors
          (PyObject *exc)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Replace the unicode encode error with
     ‘\N{...}’ escapes.

     Added in version 3.5.


File: python.info,  Node: Codec utility variables,  Prev: Registry API for Unicode encoding error handlers,  Up: Codec registry and support functions

7.6.11.3 Codec utility variables
................................

 -- C Variable: const char *Py_hexdigits

     A string constant containing the lowercase hexadecimal digits:
     ‘"0123456789abcdef"’.

     Added in version 3.3.


File: python.info,  Node: PyTime C API,  Next: Support for Perf Maps,  Prev: Codec registry and support functions,  Up: Utilities<2>

7.6.12 PyTime C API
-------------------

Added in version 3.13.

The clock C API provides access to system clocks.  It is similar to the
Python *note time: ee. module.

For C API related to the *note datetime: 30. module, see *note DateTime
Objects: 4f1e.

* Menu:

* Types: Types<2>.
* Clock Functions::
* Raw Clock Functions::
* Conversion functions::


File: python.info,  Node: Types<2>,  Next: Clock Functions,  Up: PyTime C API

7.6.12.1 Types
..............

 -- C Type: type PyTime_t

     A timestamp or duration in nanoseconds, represented as a signed
     64-bit integer.

     The reference point for timestamps depends on the clock used.  For
     example, *note PyTime_Time(): 336. returns timestamps relative to
     the UNIX epoch.

     The supported range is around [-292.3 years; +292.3 years].  Using
     the Unix epoch (January 1st, 1970) as reference, the supported date
     range is around [1677-09-21; 2262-04-11].  The exact limits are
     exposed as constants:

 -- C Variable: *note PyTime_t: 32e. PyTime_MIN

     Minimum value of *note PyTime_t: 32e.

 -- C Variable: *note PyTime_t: 32e. PyTime_MAX

     Maximum value of *note PyTime_t: 32e.


File: python.info,  Node: Clock Functions,  Next: Raw Clock Functions,  Prev: Types<2>,  Up: PyTime C API

7.6.12.2 Clock Functions
........................

The following functions take a pointer to a *note PyTime_t: 32e. that
they set to the value of a particular clock.  Details of each clock are
given in the documentation of the corresponding Python function.

The functions return ‘0’ on success, or ‘-1’ (with an exception set) on
failure.

On integer overflow, they set the *note PyExc_OverflowError: 4cc8.
exception and set ‘*result’ to the value clamped to the ‘[PyTime_MIN;
PyTime_MAX]’ range.  (On current systems, integer overflows are likely
caused by misconfigured system time.)

As any other C API (unless otherwise specified), the functions must be
called with the *note GIL: 159. held.

 -- C Function: int PyTime_Monotonic (PyTime_t *result)

     Read the monotonic clock.  See *note time.monotonic(): 253. for
     important details on this clock.

 -- C Function: int PyTime_PerfCounter (PyTime_t *result)

     Read the performance counter.  See *note time.perf_counter(): a97.
     for important details on this clock.

 -- C Function: int PyTime_Time (PyTime_t *result)

     Read the “wall clock” time.  See *note time.time(): 254. for
     details important on this clock.


File: python.info,  Node: Raw Clock Functions,  Next: Conversion functions,  Prev: Clock Functions,  Up: PyTime C API

7.6.12.3 Raw Clock Functions
............................

Similar to clock functions, but don’t set an exception on error and
don’t require the caller to hold the GIL.

On success, the functions return ‘0’.

On failure, they set ‘*result’ to ‘0’ and return ‘-1’, 'without' setting
an exception.  To get the cause of the error, acquire the GIL and call
the regular (non-‘Raw’) function.  Note that the regular function may
succeed after the ‘Raw’ one failed.

 -- C Function: int PyTime_MonotonicRaw (PyTime_t *result)

     Similar to *note PyTime_Monotonic(): 332, but don’t set an
     exception on error and don’t require holding the GIL.

 -- C Function: int PyTime_PerfCounterRaw (PyTime_t *result)

     Similar to *note PyTime_PerfCounter(): 334, but don’t set an
     exception on error and don’t require holding the GIL.

 -- C Function: int PyTime_TimeRaw (PyTime_t *result)

     Similar to *note PyTime_Time(): 336, but don’t set an exception on
     error and don’t require holding the GIL.


File: python.info,  Node: Conversion functions,  Prev: Raw Clock Functions,  Up: PyTime C API

7.6.12.4 Conversion functions
.............................

 -- C Function: double PyTime_AsSecondsDouble (PyTime_t t)

     Convert a timestamp to a number of seconds as a C double.

     The function cannot fail, but note that double has limited accuracy
     for large values.


File: python.info,  Node: Support for Perf Maps,  Prev: PyTime C API,  Up: Utilities<2>

7.6.13 Support for Perf Maps
----------------------------

On supported platforms (as of this writing, only Linux), the runtime can
take advantage of 'perf map files' to make Python functions visible to
an external profiling tool (such as perf(1)).  A running process may
create a file in the ‘/tmp’ directory, which contains entries that can
map a section of executable code to a name.  This interface is described
in the documentation of the Linux Perf tool(2).

In Python, these helper APIs can be used by libraries and features that
rely on generating machine code on the fly.

Note that holding the Global Interpreter Lock (GIL) is not required for
these APIs.

 -- C Function: int PyUnstable_PerfMapState_Init (void)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Open the ‘/tmp/perf-$pid.map’ file, unless it’s already opened, and
     create a lock to ensure thread-safe writes to the file (provided
     the writes are done through *note PyUnstable_WritePerfMapEntry():
     184a.).  Normally, there’s no need to call this explicitly; just
     use ‘PyUnstable_WritePerfMapEntry()’ and it will initialize the
     state on first call.

     Returns ‘0’ on success, ‘-1’ on failure to create/open the perf map
     file, or ‘-2’ on failure to create a lock.  Check ‘errno’ for more
     information about the cause of a failure.

 -- C Function: int PyUnstable_WritePerfMapEntry (const void *code_addr,
          unsigned int code_size, const char *entry_name)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Write one single entry to the ‘/tmp/perf-$pid.map’ file.  This
     function is thread safe.  Here is what an example entry looks like:

          # address      size  name
          7f3529fcf759 b     py::bar:/run/t.py

     Will call *note PyUnstable_PerfMapState_Init(): 184b. before
     writing the entry, if the perf map file is not already opened.
     Returns ‘0’ on success, or the same error codes as
     ‘PyUnstable_PerfMapState_Init()’ on failure.

 -- C Function: void PyUnstable_PerfMapState_Fini (void)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Close the perf map file opened by *note
     PyUnstable_PerfMapState_Init(): 184b.  This is called by the
     runtime itself during interpreter shut-down.  In general, there
     shouldn’t be a reason to explicitly call this, except to handle
     specific scenarios such as forking.

   ---------- Footnotes ----------

   (1) https://perf.wiki.kernel.org/index.php/Main_Page

   (2) 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/Documentation/jit-interface.txt


File: python.info,  Node: Abstract Objects Layer,  Next: Concrete Objects Layer,  Prev: Utilities<2>,  Up: Python/C API Reference Manual

7.7 Abstract Objects Layer
==========================

The functions in this chapter interact with Python objects regardless of
their type, or with wide classes of object types (e.g.  all numerical
types, or all sequence types).  When used on object types for which they
do not apply, they will raise a Python exception.

It is not possible to use these functions on objects that are not
properly initialized, such as a list object that has been created by
*note PyList_New(): 4c0b, but whose items have not been set to some
non-‘NULL’ value yet.

* Menu:

* Object Protocol::
* Call Protocol::
* Number Protocol::
* Sequence Protocol::
* Mapping Protocol::
* Iterator Protocol::
* Buffer Protocol::


File: python.info,  Node: Object Protocol,  Next: Call Protocol,  Up: Abstract Objects Layer

7.7.1 Object Protocol
---------------------

 -- C Function: *note PyObject: 33a. *Py_GetConstant (unsigned int
          constant_id)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Get a
     *note strong reference: 33e. to a constant.

     Set an exception and return ‘NULL’ if 'constant_id' is invalid.

     'constant_id' must be one of these constant identifiers:

     Constant Identifier                          Value     Returned object
                                                            
     -------------------------------------------------------------------------------------
                                                            
      -- C Macro: Py_CONSTANT_NONE                ‘0’       *note None: 678.
                                                            
                                                            
      -- C Macro: Py_CONSTANT_FALSE               ‘1’       *note False: b4f.
                                                            
                                                            
      -- C Macro: Py_CONSTANT_TRUE                ‘2’       *note True: c2d.
                                                            
                                                            
      -- C Macro: Py_CONSTANT_ELLIPSIS            ‘3’       *note Ellipsis: 233f.
                                                            
                                                            
      -- C Macro: Py_CONSTANT_NOT_IMPLEMENTED     ‘4’       *note NotImplemented: 7d6.
                                                            
                                                            
      -- C Macro: Py_CONSTANT_ZERO                ‘5’       ‘0’
                                                            
                                                            
      -- C Macro: Py_CONSTANT_ONE                 ‘6’       ‘1’
                                                            
                                                            
      -- C Macro: Py_CONSTANT_EMPTY_STR           ‘7’       ‘''’
                                                            
                                                            
      -- C Macro: Py_CONSTANT_EMPTY_BYTES         ‘8’       ‘b''’
                                                            
                                                            
      -- C Macro: Py_CONSTANT_EMPTY_TUPLE         ‘9’       ‘()’
                                                            

     Numeric values are only given for projects which cannot use the
     constant identifiers.

     Added in version 3.13.

     'CPython implementation detail:' In CPython, all of these constants
     are *note immortal: 45dd.

 -- C Function: *note PyObject: 33a. *Py_GetConstantBorrowed (unsigned
          int constant_id)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note Py_GetConstant(): 357, but return a *note borrowed
     reference: 33f.

     This function is primarily intended for backwards compatibility:
     using *note Py_GetConstant(): 357. is recommended for new code.

     The reference is borrowed from the interpreter, and is valid until
     the interpreter finalization.

     Added in version 3.13.

 -- C Variable: *note PyObject: 33a. *Py_NotImplemented

     The ‘NotImplemented’ singleton, used to signal that an operation is
     not implemented for the given type combination.

 -- C Macro: Py_RETURN_NOTIMPLEMENTED

     Properly handle returning *note Py_NotImplemented: 4f37. from
     within a C function (that is, create a new *note strong reference:
     33e. to *note NotImplemented: 7d6. and return it).

 -- C Macro: Py_PRINT_RAW

     Flag to be used with multiple functions that print the object (like
     *note PyObject_Print(): 16fa. and *note PyFile_WriteObject():
     4ce8.).  If passed, these functions use the *note str(): 44f. of
     the object instead of the *note repr(): 803.

 -- C Function: int PyObject_Print (PyObject *o, FILE *fp, int flags)

     Print an object 'o', on file 'fp'.  Returns ‘-1’ on error.  The
     flags argument is used to enable certain printing options.  The
     only option currently supported is *note Py_PRINT_RAW: 4f38.; if
     given, the *note str(): 44f. of the object is written instead of
     the *note repr(): 803.

 -- C Function: int PyObject_HasAttrWithError (PyObject *o, PyObject
          *attr_name)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Returns
     ‘1’ if 'o' has the attribute 'attr_name', and ‘0’ otherwise.  This
     is equivalent to the Python expression ‘hasattr(o, attr_name)’.  On
     failure, return ‘-1’.

     Added in version 3.13.

 -- C Function: int PyObject_HasAttrStringWithError (PyObject *o, const
          char *attr_name)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  This is
     the same as *note PyObject_HasAttrWithError(): 37d, but 'attr_name'
     is specified as a const char* UTF-8 encoded bytes string, rather
     than a *note PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: int PyObject_HasAttr (PyObject *o, PyObject *attr_name)
     ' Part of the *note Stable ABI: 556.'  Returns ‘1’ if 'o' has the
     attribute 'attr_name', and ‘0’ otherwise.  This function always
     succeeds.

          Note: Exceptions that occur when this calls *note
          __getattr__(): 4d6. and *note __getattribute__(): bf1. methods
          aren’t propagated, but instead given to *note
          sys.unraisablehook(): 1f7.  For proper error handling, use
          *note PyObject_HasAttrWithError(): 37d, *note
          PyObject_GetOptionalAttr(): 34a. or *note PyObject_GetAttr():
          34c. instead.

 -- C Function: int PyObject_HasAttrString (PyObject *o, const char
          *attr_name)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyObject_HasAttr(): 37e, but 'attr_name' is specified as a const
     char* UTF-8 encoded bytes string, rather than a *note PyObject:
     33a.*.

          Note: Exceptions that occur when this calls *note
          __getattr__(): 4d6. and *note __getattribute__(): bf1. methods
          or while creating the temporary *note str: 44f. object are
          silently ignored.  For proper error handling, use *note
          PyObject_HasAttrStringWithError(): 37f, *note
          PyObject_GetOptionalAttrString(): 34b. or *note
          PyObject_GetAttrString(): 34d. instead.

 -- C Function: *note PyObject: 33a. *PyObject_GetAttr (PyObject *o,
          PyObject *attr_name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Retrieve an attribute named 'attr_name' from object 'o'.
     Returns the attribute value on success, or ‘NULL’ on failure.  This
     is the equivalent of the Python expression ‘o.attr_name’.

     If the missing attribute should not be treated as a failure, you
     can use *note PyObject_GetOptionalAttr(): 34a. instead.

 -- C Function: *note PyObject: 33a. *PyObject_GetAttrString (PyObject
          *o, const char *attr_name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is the same as *note PyObject_GetAttr(): 34c, but
     'attr_name' is specified as a const char* UTF-8 encoded bytes
     string, rather than a *note PyObject: 33a.*.

     If the missing attribute should not be treated as a failure, you
     can use *note PyObject_GetOptionalAttrString(): 34b. instead.

 -- C Function: int PyObject_GetOptionalAttr (PyObject *obj, PyObject
          *attr_name, PyObject **result);
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Variant
     of *note PyObject_GetAttr(): 34c. which doesn’t raise *note
     AttributeError: 34e. if the attribute is not found.

     If the attribute is found, return ‘1’ and set '*result' to a new
     *note strong reference: 33e. to the attribute.  If the attribute is
     not found, return ‘0’ and set '*result' to ‘NULL’; the *note
     AttributeError: 34e. is silenced.  If an error other than
     ‘AttributeError’ is raised, return ‘-1’ and set '*result' to
     ‘NULL’.

     Added in version 3.13.

 -- C Function: int PyObject_GetOptionalAttrString (PyObject *obj, const
          char *attr_name, PyObject **result);
     ' Part of the *note Stable ABI: 556. since version 3.13.'  This is
     the same as *note PyObject_GetOptionalAttr(): 34a, but 'attr_name'
     is specified as a const char* UTF-8 encoded bytes string, rather
     than a *note PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyObject_GenericGetAttr (PyObject
          *o, PyObject *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Generic attribute getter function that is meant to be put
     into a type object’s ‘tp_getattro’ slot.  It looks for a descriptor
     in the dictionary of classes in the object’s MRO as well as an
     attribute in the object’s *note __dict__: 55e. (if present).  As
     outlined in *note Implementing Descriptors: c70, data descriptors
     take preference over instance attributes, while non-data
     descriptors don’t.  Otherwise, an *note AttributeError: 34e. is
     raised.

 -- C Function: int PyObject_SetAttr (PyObject *o, PyObject *attr_name,
          PyObject *v)
     ' Part of the *note Stable ABI: 556.'  Set the value of the
     attribute named 'attr_name', for object 'o', to the value 'v'.
     Raise an exception and return ‘-1’ on failure; return ‘0’ on
     success.  This is the equivalent of the Python statement
     ‘o.attr_name = v’.

     If 'v' is ‘NULL’, the attribute is deleted.  This behaviour is
     deprecated in favour of using *note PyObject_DelAttr(): 163f, but
     there are currently no plans to remove it.

 -- C Function: int PyObject_SetAttrString (PyObject *o, const char
          *attr_name, PyObject *v)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyObject_SetAttr(): 4d5d, but 'attr_name' is specified as a const
     char* UTF-8 encoded bytes string, rather than a *note PyObject:
     33a.*.

     If 'v' is ‘NULL’, the attribute is deleted, but this feature is
     deprecated in favour of using *note PyObject_DelAttrString(): 1640.

     The number of different attribute names passed to this function
     should be kept small, usually by using a statically allocated
     string as 'attr_name'.  For attribute names that aren’t known at
     compile time, prefer calling *note PyUnicode_FromString(): 4dda.
     and *note PyObject_SetAttr(): 4d5d. directly.  For more details,
     see *note PyUnicode_InternFromString(): 1708, which may be used
     internally to create a key object.

 -- C Function: int PyObject_GenericSetAttr (PyObject *o, PyObject
          *name, PyObject *value)
     ' Part of the *note Stable ABI: 556.'  Generic attribute setter and
     deleter function that is meant to be put into a type object’s *note
     tp_setattro: 4bb2. slot.  It looks for a data descriptor in the
     dictionary of classes in the object’s MRO, and if found it takes
     preference over setting or deleting the attribute in the instance
     dictionary.  Otherwise, the attribute is set or deleted in the
     object’s *note __dict__: 55e. (if present).  On success, ‘0’ is
     returned, otherwise an *note AttributeError: 34e. is raised and
     ‘-1’ is returned.

 -- C Function: int PyObject_DelAttr (PyObject *o, PyObject *attr_name)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Delete
     attribute named 'attr_name', for object 'o'.  Returns ‘-1’ on
     failure.  This is the equivalent of the Python statement ‘del
     o.attr_name’.

 -- C Function: int PyObject_DelAttrString (PyObject *o, const char
          *attr_name)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  This is
     the same as *note PyObject_DelAttr(): 163f, but 'attr_name' is
     specified as a const char* UTF-8 encoded bytes string, rather than
     a *note PyObject: 33a.*.

     The number of different attribute names passed to this function
     should be kept small, usually by using a statically allocated
     string as 'attr_name'.  For attribute names that aren’t known at
     compile time, prefer calling *note PyUnicode_FromString(): 4dda.
     and *note PyObject_DelAttr(): 163f. directly.  For more details,
     see *note PyUnicode_InternFromString(): 1708, which may be used
     internally to create a key object for lookup.

 -- C Function: *note PyObject: 33a. *PyObject_GenericGetDict (PyObject
          *o, void *context)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.10.'  A generic implementation for the getter of a
     ‘__dict__’ descriptor.  It creates the dictionary if necessary.

     This function may also be called to get the *note __dict__: 55e. of
     the object 'o'.  Pass ‘NULL’ for 'context' when calling it.  Since
     this function may need to allocate memory for the dictionary, it
     may be more efficient to call *note PyObject_GetAttr(): 34c. when
     accessing an attribute on the object.

     On failure, returns ‘NULL’ with an exception set.

     Added in version 3.3.

 -- C Function: int PyObject_GenericSetDict (PyObject *o, PyObject
          *value, void *context)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  A generic
     implementation for the setter of a ‘__dict__’ descriptor.  This
     implementation does not allow the dictionary to be deleted.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. **_PyObject_GetDictPtr (PyObject
          *obj)

     Return a pointer to *note __dict__: 55e. of the object 'obj'.  If
     there is no ‘__dict__’, return ‘NULL’ without setting an exception.

     This function may need to allocate memory for the dictionary, so it
     may be more efficient to call *note PyObject_GetAttr(): 34c. when
     accessing an attribute on the object.

 -- C Function: *note PyObject: 33a. *PyObject_RichCompare (PyObject
          *o1, PyObject *o2, int opid)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Compare the values of 'o1' and 'o2' using the operation
     specified by 'opid', which must be one of *note Py_LT: 4f3a, *note
     Py_LE: 4f3b, *note Py_EQ: 4f3c, *note Py_NE: 4f3d, *note Py_GT:
     4f3e, or *note Py_GE: 4f3f, corresponding to ‘<’, ‘<=’, ‘==’, ‘!=’,
     ‘>’, or ‘>=’ respectively.  This is the equivalent of the Python
     expression ‘o1 op o2’, where ‘op’ is the operator corresponding to
     'opid'.  Returns the value of the comparison on success, or ‘NULL’
     on failure.

 -- C Function: int PyObject_RichCompareBool (PyObject *o1, PyObject
          *o2, int opid)
     ' Part of the *note Stable ABI: 556.'  Compare the values of 'o1'
     and 'o2' using the operation specified by 'opid', like *note
     PyObject_RichCompare(): 4bbb, but returns ‘-1’ on error, ‘0’ if the
     result is false, ‘1’ otherwise.

     Note: If 'o1' and 'o2' are the same object, *note
     PyObject_RichCompareBool(): 1b35. will always return ‘1’ for *note
     Py_EQ: 4f3c. and ‘0’ for *note Py_NE: 4f3d.

 -- C Function: *note PyObject: 33a. *PyObject_Format (PyObject *obj,
          PyObject *format_spec)
     ' Part of the *note Stable ABI: 556.'  Format 'obj' using
     'format_spec'.  This is equivalent to the Python expression
     ‘format(obj, format_spec)’.

     'format_spec' may be ‘NULL’.  In this case the call is equivalent
     to ‘format(obj)’.  Returns the formatted string on success, ‘NULL’
     on failure.

 -- C Function: *note PyObject: 33a. *PyObject_Repr (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Compute a string representation of object 'o'.  Returns the string
     representation on success, ‘NULL’ on failure.  This is the
     equivalent of the Python expression ‘repr(o)’.  Called by the *note
     repr(): 803. built-in function.

     If argument is ‘NULL’, return the string ‘'<NULL>'’.

     Changed in version 3.4: This function now includes a debug
     assertion to help ensure that it does not silently discard an
     active exception.

 -- C Function: *note PyObject: 33a. *PyObject_ASCII (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     As *note PyObject_Repr(): 106c, compute a string representation of
     object 'o', but escape the non-ASCII characters in the string
     returned by ‘PyObject_Repr()’ with ‘\x’, ‘\u’ or ‘\U’ escapes.
     This generates a string similar to that returned by
     ‘PyObject_Repr()’ in Python 2.  Called by the *note ascii(): 1434.
     built-in function.

     If argument is ‘NULL’, return the string ‘'<NULL>'’.

 -- C Function: *note PyObject: 33a. *PyObject_Str (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Compute a string representation of object 'o'.  Returns the
     string representation on success, ‘NULL’ on failure.  This is the
     equivalent of the Python expression ‘str(o)’.  Called by the *note
     str(): 44f. built-in function and, therefore, by the *note print():
     fae. function.

     If argument is ‘NULL’, return the string ‘'<NULL>'’.

     Changed in version 3.4: This function now includes a debug
     assertion to help ensure that it does not silently discard an
     active exception.

 -- C Function: *note PyObject: 33a. *PyObject_Bytes (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Compute a bytes representation of object 'o'.  ‘NULL’ is returned
     on failure and a bytes object on success.  This is equivalent to
     the Python expression ‘bytes(o)’, when 'o' is not an integer.
     Unlike ‘bytes(o)’, a TypeError is raised when 'o' is an integer
     instead of a zero-initialized bytes object.

     If argument is ‘NULL’, return the *note bytes: 1c2. object
     ‘b'<NULL>'’.

 -- C Function: int PyObject_IsSubclass (PyObject *derived, PyObject
          *cls)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if the class
     'derived' is identical to or derived from the class 'cls',
     otherwise return ‘0’.  In case of an error, return ‘-1’.

     If 'cls' is a tuple, the check will be done against every entry in
     'cls'.  The result will be ‘1’ when at least one of the checks
     returns ‘1’, otherwise it will be ‘0’.

     If 'cls' has a *note __subclasscheck__(): 212d. method, it will be
     called to determine the subclass status as described in PEP
     3119(1).  Otherwise, 'derived' is a subclass of 'cls' if it is a
     direct or indirect subclass, i.e.  contained in *note cls.__mro__:
     20da.

     Normally only class objects, i.e.  instances of *note type: d71. or
     a derived class, are considered classes.  However, objects can
     override this by having a *note __bases__: 14fb. attribute (which
     must be a tuple of base classes).

 -- C Function: int PyObject_IsInstance (PyObject *inst, PyObject *cls)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if 'inst' is an
     instance of the class 'cls' or a subclass of 'cls', or ‘0’ if not.
     On error, returns ‘-1’ and sets an exception.

     If 'cls' is a tuple, the check will be done against every entry in
     'cls'.  The result will be ‘1’ when at least one of the checks
     returns ‘1’, otherwise it will be ‘0’.

     If 'cls' has a *note __instancecheck__(): 212c. method, it will be
     called to determine the subclass status as described in PEP
     3119(2).  Otherwise, 'inst' is an instance of 'cls' if its class is
     a subclass of 'cls'.

     An instance 'inst' can override what is considered its class by
     having a *note __class__: 14fc. attribute.

     An object 'cls' can override if it is considered a class, and what
     its base classes are, by having a *note __bases__: 14fb. attribute
     (which must be a tuple of base classes).

 -- C Function: *note Py_hash_t: 12aa. PyObject_Hash (PyObject *o)
     ' Part of the *note Stable ABI: 556.'

     Compute and return the hash value of an object 'o'.  On failure,
     return ‘-1’.  This is the equivalent of the Python expression
     ‘hash(o)’.

     Changed in version 3.2: The return type is now Py_hash_t.  This is
     a signed integer the same size as *note Py_ssize_t: a6e.

 -- C Function: *note Py_hash_t: 12aa. PyObject_HashNotImplemented
          (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Set a *note TypeError: 2c3.
     indicating that ‘type(o)’ is not *note hashable: 613. and return
     ‘-1’.  This function receives special treatment when stored in a
     ‘tp_hash’ slot, allowing a type to explicitly indicate to the
     interpreter that it is not hashable.

 -- C Function: int PyObject_IsTrue (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Returns ‘1’ if the object
     'o' is considered to be true, and ‘0’ otherwise.  This is
     equivalent to the Python expression ‘not not o’.  On failure,
     return ‘-1’.

 -- C Function: int PyObject_Not (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Returns ‘0’ if the object
     'o' is considered to be true, and ‘1’ otherwise.  This is
     equivalent to the Python expression ‘not o’.  On failure, return
     ‘-1’.

 -- C Function: *note PyObject: 33a. *PyObject_Type (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     When 'o' is non-‘NULL’, returns a type object corresponding to the
     object type of object 'o'.  On failure, raises *note SystemError:
     578. and returns ‘NULL’.  This is equivalent to the Python
     expression ‘type(o)’.  This function creates a new *note strong
     reference: 33e. to the return value.  There’s really no reason to
     use this function instead of the *note Py_TYPE(): 783. function,
     which returns a pointer of type *note PyTypeObject: aba.*, except
     when a new strong reference is needed.

 -- C Function: int PyObject_TypeCheck (PyObject *o, PyTypeObject *type)

     Return non-zero if the object 'o' is of type 'type' or a subtype of
     'type', and ‘0’ otherwise.  Both parameters must be non-‘NULL’.

 -- C Function: *note Py_ssize_t: a6e. PyObject_Size (PyObject *o)
 -- C Function: *note Py_ssize_t: a6e. PyObject_Length (PyObject *o)
     ' Part of the *note Stable ABI: 556.'

     Return the length of object 'o'.  If the object 'o' provides either
     the sequence and mapping protocols, the sequence length is
     returned.  On error, ‘-1’ is returned.  This is the equivalent to
     the Python expression ‘len(o)’.

 -- C Function: *note Py_ssize_t: a6e. PyObject_LengthHint (PyObject *o,
          Py_ssize_t defaultvalue)

     Return an estimated length for the object 'o'.  First try to return
     its actual length, then an estimate using *note __length_hint__():
     f42, and finally return the default value.  On error return ‘-1’.
     This is the equivalent to the Python expression
     ‘operator.length_hint(o, defaultvalue)’.

     Added in version 3.4.

 -- C Function: *note PyObject: 33a. *PyObject_GetItem (PyObject *o,
          PyObject *key)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return element of 'o' corresponding to the object 'key' or
     ‘NULL’ on failure.  This is the equivalent of the Python expression
     ‘o[key]’.

 -- C Function: int PyObject_SetItem (PyObject *o, PyObject *key,
          PyObject *v)
     ' Part of the *note Stable ABI: 556.'  Map the object 'key' to the
     value 'v'.  Raise an exception and return ‘-1’ on failure; return
     ‘0’ on success.  This is the equivalent of the Python statement
     ‘o[key] = v’.  This function 'does not' steal a reference to 'v'.

 -- C Function: int PyObject_DelItem (PyObject *o, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Remove the mapping for the
     object 'key' from the object 'o'.  Return ‘-1’ on failure.  This is
     equivalent to the Python statement ‘del o[key]’.

 -- C Function: int PyObject_DelItemString (PyObject *o, const char
          *key)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyObject_DelItem(): 4d50, but 'key' is specified as a const char*
     UTF-8 encoded bytes string, rather than a *note PyObject: 33a.*.

 -- C Function: *note PyObject: 33a. *PyObject_Dir (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is equivalent to the Python expression ‘dir(o)’,
     returning a (possibly empty) list of strings appropriate for the
     object argument, or ‘NULL’ if there was an error.  If the argument
     is ‘NULL’, this is like the Python ‘dir()’, returning the names of
     the current locals; in this case, if no execution frame is active
     then ‘NULL’ is returned but *note PyErr_Occurred(): 1a55. will
     return false.

 -- C Function: *note PyObject: 33a. *PyObject_GetIter (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is equivalent to the Python expression ‘iter(o)’.  It
     returns a new iterator for the object argument, or the object
     itself if the object is already an iterator.  Raises *note
     TypeError: 2c3. and returns ‘NULL’ if the object cannot be
     iterated.

 -- C Function: *note PyObject: 33a. *PyObject_SelfIter (PyObject *obj)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is equivalent to the Python ‘__iter__(self): return
     self’ method.  It is intended for *note iterator: 1ac. types, to be
     used in the *note PyTypeObject.tp_iter: 153e. slot.

 -- C Function: *note PyObject: 33a. *PyObject_GetAIter (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.10.'  This is the equivalent to the Python
     expression ‘aiter(o)’.  Takes an ‘AsyncIterable’ object and returns
     an ‘AsyncIterator’ for it.  This is typically a new iterator but if
     the argument is an ‘AsyncIterator’, this returns itself.  Raises
     *note TypeError: 2c3. and returns ‘NULL’ if the object cannot be
     iterated.

     Added in version 3.10.

 -- C Function: void *PyObject_GetTypeData (PyObject *o, PyTypeObject
          *cls)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Get a
     pointer to subclass-specific data reserved for 'cls'.

     The object 'o' must be an instance of 'cls', and 'cls' must have
     been created using negative *note PyType_Spec.basicsize: 54b.
     Python does not check this.

     On error, set an exception and return ‘NULL’.

     Added in version 3.12.

 -- C Function: *note Py_ssize_t: a6e. PyType_GetTypeDataSize
          (PyTypeObject *cls)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Return
     the size of the instance memory space reserved for 'cls', i.e.  the
     size of the memory *note PyObject_GetTypeData(): 54c. returns.

     This may be larger than requested using *note
     -PyType_Spec.basicsize: 54b.; it is safe to use this larger size
     (e.g.  with ‘memset()’).

     The type 'cls' 'must' have been created using negative *note
     PyType_Spec.basicsize: 54b.  Python does not check this.

     On error, set an exception and return a negative value.

     Added in version 3.12.

 -- C Function: void *PyObject_GetItemData (PyObject *o)

     Get a pointer to per-item data for a class with *note
     Py_TPFLAGS_ITEMS_AT_END: 54e.

     On error, set an exception and return ‘NULL’.  *note TypeError:
     2c3. is raised if 'o' does not have *note Py_TPFLAGS_ITEMS_AT_END:
     54e. set.

     Added in version 3.12.

 -- C Function: int PyObject_VisitManagedDict (PyObject *obj, visitproc
          visit, void *arg)

     Visit the managed dictionary of 'obj'.

     This function must only be called in a traverse function of the
     type which has the *note Py_TPFLAGS_MANAGED_DICT: 36e. flag set.

     Added in version 3.13.

 -- C Function: void PyObject_ClearManagedDict (PyObject *obj)

     Clear the managed dictionary of 'obj'.

     This function must only be called in a clear function of the type
     which has the *note Py_TPFLAGS_MANAGED_DICT: 36e. flag set.

     Added in version 3.13.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3119/

   (2) https://peps.python.org/pep-3119/


File: python.info,  Node: Call Protocol,  Next: Number Protocol,  Prev: Object Protocol,  Up: Abstract Objects Layer

7.7.2 Call Protocol
-------------------

CPython supports two different calling protocols: 'tp_call' and
vectorcall.

* Menu:

* The tp_call Protocol::
* The Vectorcall Protocol::
* Object Calling API::
* Call Support API::


File: python.info,  Node: The tp_call Protocol,  Next: The Vectorcall Protocol,  Up: Call Protocol

7.7.2.1 The 'tp_call' Protocol
..............................

Instances of classes that set *note tp_call: 55c. are callable.  The
signature of the slot is:

     PyObject *tp_call(PyObject *callable, PyObject *args, PyObject *kwargs);

A call is made using a tuple for the positional arguments and a dict for
the keyword arguments, similarly to ‘callable(*args, **kwargs)’ in
Python code.  'args' must be non-NULL (use an empty tuple if there are
no arguments) but 'kwargs' may be 'NULL' if there are no keyword
arguments.

This convention is not only used by 'tp_call': *note tp_new: 582. and
*note tp_init: 584. also pass arguments this way.

To call an object, use *note PyObject_Call(): 39f. or another *note call
API: 4f44.


File: python.info,  Node: The Vectorcall Protocol,  Next: Object Calling API,  Prev: The tp_call Protocol,  Up: Call Protocol

7.7.2.2 The Vectorcall Protocol
...............................

Added in version 3.9.

The vectorcall protocol was introduced in PEP 590(1) as an additional
protocol for making calls more efficient.

As rule of thumb, CPython will prefer the vectorcall for internal calls
if the callable supports it.  However, this is not a hard rule.
Additionally, some third-party extensions use 'tp_call' directly (rather
than using *note PyObject_Call(): 39f.).  Therefore, a class supporting
vectorcall must also implement *note tp_call: 55c.  Moreover, the
callable must behave the same regardless of which protocol is used.  The
recommended way to achieve this is by setting ‘tp_call’ to *note
PyVectorcall_Call(): 559.  This bears repeating:

     Warning: A class supporting vectorcall 'must' also implement *note
     tp_call: 55c. with the same semantics.

Changed in version 3.12: The *note Py_TPFLAGS_HAVE_VECTORCALL: 557. flag
is now removed from a class when the class’s *note __call__(): 55b.
method is reassigned.  (This internally sets *note tp_call: 55c. only,
and thus may make it behave differently than the vectorcall function.)
In earlier Python versions, vectorcall should only be used with *note
immutable: 3c5. or static types.

A class should not implement vectorcall if that would be slower than
'tp_call'.  For example, if the callee needs to convert the arguments to
an args tuple and kwargs dict anyway, then there is no point in
implementing vectorcall.

Classes can implement the vectorcall protocol by enabling the *note
Py_TPFLAGS_HAVE_VECTORCALL: 557. flag and setting *note
tp_vectorcall_offset: 4f46. to the offset inside the object structure
where a 'vectorcallfunc' appears.  This is a pointer to a function with
the following signature:

 -- C Type: typedef *note PyObject: 33a. *(*vectorcallfunc)(*note
          PyObject: 33a. *callable, *note PyObject: 33a. *const *args,
          size_t nargsf, *note PyObject: 33a. *kwnames)
     ' Part of the *note Stable ABI: 556. since version 3.12.'

   - 'callable' is the object being called.

   - 
     'args' is a C array consisting of the positional arguments followed by the

          values of the keyword arguments.  This can be 'NULL' if there
          are no arguments.

   - 
     'nargsf' is the number of positional arguments plus possibly the

          *note PY_VECTORCALL_ARGUMENTS_OFFSET: 561. flag.  To get the
          actual number of positional arguments from 'nargsf', use *note
          PyVectorcall_NARGS(): 558.

   - 
     'kwnames' is a tuple containing the names of the keyword arguments;

          in other words, the keys of the kwargs dict.  These names must
          be strings (instances of ‘str’ or a subclass) and they must be
          unique.  If there are no keyword arguments, then 'kwnames' can
          instead be 'NULL'.

 -- C Macro: PY_VECTORCALL_ARGUMENTS_OFFSET
     ' Part of the *note Stable ABI: 556. since version 3.12.'  If this
     flag is set in a vectorcall 'nargsf' argument, the callee is
     allowed to temporarily change ‘args[-1]’.  In other words, 'args'
     points to argument 1 (not 0) in the allocated vector.  The callee
     must restore the value of ‘args[-1]’ before returning.

     For *note PyObject_VectorcallMethod(): 560, this flag means instead
     that ‘args[0]’ may be changed.

     Whenever they can do so cheaply (without additional allocation),
     callers are encouraged to use *note PY_VECTORCALL_ARGUMENTS_OFFSET:
     561.  Doing so will allow callables such as bound methods to make
     their onward calls (which include a prepended 'self' argument) very
     efficiently.

     Added in version 3.8.

To call an object that implements vectorcall, use a *note call API:
4f44. function as with any other callable.  *note PyObject_Vectorcall():
55f. will usually be most efficient.

* Menu:

* Recursion Control: Recursion Control<2>.
* Vectorcall Support API::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0590/


File: python.info,  Node: Recursion Control<2>,  Next: Vectorcall Support API,  Up: The Vectorcall Protocol

7.7.2.3 Recursion Control
.........................

When using 'tp_call', callees do not need to worry about *note
recursion: 4ebe.: CPython uses *note Py_EnterRecursiveCall(): 97d. and
*note Py_LeaveRecursiveCall(): 97e. for calls made using 'tp_call'.

For efficiency, this is not the case for calls done using vectorcall:
the callee should use 'Py_EnterRecursiveCall' and
'Py_LeaveRecursiveCall' if needed.


File: python.info,  Node: Vectorcall Support API,  Prev: Recursion Control<2>,  Up: The Vectorcall Protocol

7.7.2.4 Vectorcall Support API
..............................

 -- C Function: *note Py_ssize_t: a6e. PyVectorcall_NARGS (size_t
          nargsf)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Given a
     vectorcall 'nargsf' argument, return the actual number of
     arguments.  Currently equivalent to:

          (Py_ssize_t)(nargsf & ~PY_VECTORCALL_ARGUMENTS_OFFSET)

     However, the function ‘PyVectorcall_NARGS’ should be used to allow
     for future extensions.

     Added in version 3.8.

 -- C Function: *note vectorcallfunc: 55a. PyVectorcall_Function
          (PyObject *op)

     If 'op' does not support the vectorcall protocol (either because
     the type does not or because the specific instance does not),
     return 'NULL'. Otherwise, return the vectorcall function pointer
     stored in 'op'.  This function never raises an exception.

     This is mostly useful to check whether or not 'op' supports
     vectorcall, which can be done by checking
     ‘PyVectorcall_Function(op) != NULL’.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyVectorcall_Call (PyObject
          *callable, PyObject *tuple, PyObject *dict)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Call
     'callable'’s *note vectorcallfunc: 55a. with positional and keyword
     arguments given in a tuple and dict, respectively.

     This is a specialized function, intended to be put in the *note
     tp_call: 55c. slot or be used in an implementation of ‘tp_call’.
     It does not check the *note Py_TPFLAGS_HAVE_VECTORCALL: 557. flag
     and it does not fall back to ‘tp_call’.

     Added in version 3.8.


File: python.info,  Node: Object Calling API,  Next: Call Support API,  Prev: The Vectorcall Protocol,  Up: Call Protocol

7.7.2.5 Object Calling API
..........................

Various functions are available for calling a Python object.  Each
converts its arguments to a convention supported by the called object –
either 'tp_call' or vectorcall.  In order to do as little conversion as
possible, pick one that best fits the format of data you have available.

The following table summarizes the available functions; please see
individual documentation for details.

Function                                       callable               args                     kwargs
                                                                                               
-------------------------------------------------------------------------------------------------------------------
                                                                                               
*note PyObject_Call(): 39f.                    ‘PyObject *’           tuple                    dict/‘NULL’
                                                                                               
                                                                                               
*note PyObject_CallNoArgs(): 39e.              ‘PyObject *’           —                        —
                                                                                               
                                                                                               
*note PyObject_CallOneArg(): 982.              ‘PyObject *’           1 object                 —
                                                                                               
                                                                                               
*note PyObject_CallObject(): 4b77.             ‘PyObject *’           tuple/‘NULL’             —
                                                                                               
                                                                                               
*note PyObject_CallFunction(): 3a1.            ‘PyObject *’           format                   —
                                                                                               
                                                                                               
*note PyObject_CallMethod(): 3a2.              obj + ‘char*’          format                   —
                                                                                               
                                                                                               
*note PyObject_CallFunctionObjArgs(): 4d4f.    ‘PyObject *’           variadic                 —
                                                                                               
                                                                                               
*note PyObject_CallMethodObjArgs(): 1b8d.      obj + name             variadic                 —
                                                                                               
                                                                                               
*note PyObject_CallMethodNoArgs(): 4f4b.       obj + name             —                        —
                                                                                               
                                                                                               
*note PyObject_CallMethodOneArg(): 4f4c.       obj + name             1 object                 —
                                                                                               
                                                                                               
*note PyObject_Vectorcall(): 55f.              ‘PyObject *’           vectorcall               vectorcall
                                                                                               
                                                                                               
*note PyObject_VectorcallDict(): 4f4d.         ‘PyObject *’           vectorcall               dict/‘NULL’
                                                                                               
                                                                                               
*note PyObject_VectorcallMethod(): 560.        arg + name             vectorcall               vectorcall
                                                                                               

 -- C Function: *note PyObject: 33a. *PyObject_Call (PyObject *callable,
          PyObject *args, PyObject *kwargs)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call a callable Python object 'callable', with arguments
     given by the tuple 'args', and named arguments given by the
     dictionary 'kwargs'.

     'args' must not be 'NULL'; use an empty tuple if no arguments are
     needed.  If no named arguments are needed, 'kwargs' can be 'NULL'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     This is the equivalent of the Python expression: ‘callable(*args,
     **kwargs)’.

 -- C Function: *note PyObject: 33a. *PyObject_CallNoArgs (PyObject
          *callable)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.10.'  Call a callable Python object 'callable'
     without any arguments.  It is the most efficient way to call a
     callable Python object without any argument.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyObject_CallOneArg (PyObject
          *callable, PyObject *arg)
     'Return value: New reference.'  Call a callable Python object
     'callable' with exactly 1 positional argument 'arg' and no keyword
     arguments.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyObject_CallObject (PyObject
          *callable, PyObject *args)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call a callable Python object 'callable', with arguments
     given by the tuple 'args'.  If no arguments are needed, then 'args'
     can be 'NULL'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     This is the equivalent of the Python expression: ‘callable(*args)’.

 -- C Function: *note PyObject: 33a. *PyObject_CallFunction (PyObject
          *callable, const char *format, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call a callable Python object 'callable', with a variable
     number of C arguments.  The C arguments are described using a *note
     Py_BuildValue(): 8af. style format string.  The format can be
     'NULL', indicating that no arguments are provided.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     This is the equivalent of the Python expression: ‘callable(*args)’.

     Note that if you only pass *note PyObject: 33a.* args, *note
     PyObject_CallFunctionObjArgs(): 4d4f. is a faster alternative.

     Changed in version 3.4: The type of 'format' was changed from ‘char
     *’.

 -- C Function: *note PyObject: 33a. *PyObject_CallMethod (PyObject
          *obj, const char *name, const char *format, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call the method named 'name' of object 'obj' with a variable
     number of C arguments.  The C arguments are described by a *note
     Py_BuildValue(): 8af. format string that should produce a tuple.

     The format can be 'NULL', indicating that no arguments are
     provided.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     This is the equivalent of the Python expression: ‘obj.name(arg1,
     arg2, ...)’.

     Note that if you only pass *note PyObject: 33a.* args, *note
     PyObject_CallMethodObjArgs(): 1b8d. is a faster alternative.

     Changed in version 3.4: The types of 'name' and 'format' were
     changed from ‘char *’.

 -- C Function: *note PyObject: 33a. *PyObject_CallFunctionObjArgs
          (PyObject *callable, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call a callable Python object 'callable', with a variable
     number of *note PyObject: 33a.* arguments.  The arguments are
     provided as a variable number of parameters followed by 'NULL'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     This is the equivalent of the Python expression: ‘callable(arg1,
     arg2, ...)’.

 -- C Function: *note PyObject: 33a. *PyObject_CallMethodObjArgs
          (PyObject *obj, PyObject *name, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Call a method of the Python object 'obj', where the name of
     the method is given as a Python string object in 'name'.  It is
     called with a variable number of *note PyObject: 33a.* arguments.
     The arguments are provided as a variable number of parameters
     followed by 'NULL'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

 -- C Function: *note PyObject: 33a. *PyObject_CallMethodNoArgs
          (PyObject *obj, PyObject *name)

     Call a method of the Python object 'obj' without arguments, where
     the name of the method is given as a Python string object in
     'name'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyObject_CallMethodOneArg
          (PyObject *obj, PyObject *name, PyObject *arg)

     Call a method of the Python object 'obj' with a single positional
     argument 'arg', where the name of the method is given as a Python
     string object in 'name'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyObject_Vectorcall (PyObject
          *callable, PyObject *const *args, size_t nargsf, PyObject
          *kwnames)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Call a
     callable Python object 'callable'.  The arguments are the same as
     for *note vectorcallfunc: 55a.  If 'callable' supports *note
     vectorcall: 555, this directly calls the vectorcall function stored
     in 'callable'.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.8: as ‘_PyObject_Vectorcall’

     Changed in version 3.9: Renamed to the current name, without the
     leading underscore.  The old provisional name is *note soft
     deprecated: 209.

 -- C Function: *note PyObject: 33a. *PyObject_VectorcallDict (PyObject
          *callable, PyObject *const *args, size_t nargsf, PyObject
          *kwdict)

     Call 'callable' with positional arguments passed exactly as in the
     *note vectorcall: 555. protocol, but with keyword arguments passed
     as a dictionary 'kwdict'.  The 'args' array contains only the
     positional arguments.

     Regardless of which protocol is used internally, a conversion of
     arguments needs to be done.  Therefore, this function should only
     be used if the caller already has a dictionary ready to use for the
     keyword arguments, but not a tuple for the positional arguments.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyObject_VectorcallMethod
          (PyObject *name, PyObject *const *args, size_t nargsf,
          PyObject *kwnames)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Call a
     method using the vectorcall calling convention.  The name of the
     method is given as a Python string 'name'.  The object whose method
     is called is 'args[0]', and the 'args' array starting at 'args[1]'
     represents the arguments of the call.  There must be at least one
     positional argument.  'nargsf' is the number of positional
     arguments including 'args[0]', plus *note
     PY_VECTORCALL_ARGUMENTS_OFFSET: 561. if the value of ‘args[0]’ may
     temporarily be changed.  Keyword arguments can be passed just like
     in *note PyObject_Vectorcall(): 55f.

     If the object has the *note Py_TPFLAGS_METHOD_DESCRIPTOR: 4df8.
     feature, this will call the unbound method object with the full
     'args' vector as arguments.

     Return the result of the call on success, or raise an exception and
     return 'NULL' on failure.

     Added in version 3.9.


File: python.info,  Node: Call Support API,  Prev: Object Calling API,  Up: Call Protocol

7.7.2.6 Call Support API
........................

 -- C Function: int PyCallable_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Determine if the object 'o'
     is callable.  Return ‘1’ if the object is callable and ‘0’
     otherwise.  This function always succeeds.


File: python.info,  Node: Number Protocol,  Next: Sequence Protocol,  Prev: Call Protocol,  Up: Abstract Objects Layer

7.7.3 Number Protocol
---------------------

 -- C Function: int PyNumber_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Returns ‘1’ if the object
     'o' provides numeric protocols, and false otherwise.  This function
     always succeeds.

     Changed in version 3.8: Returns ‘1’ if 'o' is an index integer.

 -- C Function: *note PyObject: 33a. *PyNumber_Add (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of adding 'o1' and 'o2', or ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘o1 +
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Subtract (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of subtracting 'o2' from 'o1', or ‘NULL’
     on failure.  This is the equivalent of the Python expression ‘o1 -
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Multiply (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of multiplying 'o1' and 'o2', or ‘NULL’
     on failure.  This is the equivalent of the Python expression ‘o1 *
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_MatrixMultiply (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Returns the result of matrix multiplication on
     'o1' and 'o2', or ‘NULL’ on failure.  This is the equivalent of the
     Python expression ‘o1 @ o2’.

     Added in version 3.5.

 -- C Function: *note PyObject: 33a. *PyNumber_FloorDivide (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the floor of 'o1' divided by 'o2', or ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘o1 //
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_TrueDivide (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a reasonable approximation for the mathematical value
     of 'o1' divided by 'o2', or ‘NULL’ on failure.  The return value is
     “approximate” because binary floating-point numbers are
     approximate; it is not possible to represent all real numbers in
     base two.  This function can return a floating-point value when
     passed two integers.  This is the equivalent of the Python
     expression ‘o1 / o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Remainder (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the remainder of dividing 'o1' by 'o2', or ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘o1 %
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Divmod (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     See the built-in function *note divmod(): 9ac.  Returns ‘NULL’ on
     failure.  This is the equivalent of the Python expression
     ‘divmod(o1, o2)’.

 -- C Function: *note PyObject: 33a. *PyNumber_Power (PyObject *o1,
          PyObject *o2, PyObject *o3)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     See the built-in function *note pow(): 9dd.  Returns ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘pow(o1,
     o2, o3)’, where 'o3' is optional.  If 'o3' is to be ignored, pass
     *note Py_None: 4b69. in its place (passing ‘NULL’ for 'o3' would
     cause an illegal memory access).

 -- C Function: *note PyObject: 33a. *PyNumber_Negative (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the negation of 'o' on success, or ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘-o’.

 -- C Function: *note PyObject: 33a. *PyNumber_Positive (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns 'o' on success, or ‘NULL’ on failure.  This is the
     equivalent of the Python expression ‘+o’.

 -- C Function: *note PyObject: 33a. *PyNumber_Absolute (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Returns the absolute value of 'o', or ‘NULL’ on failure.  This is
     the equivalent of the Python expression ‘abs(o)’.

 -- C Function: *note PyObject: 33a. *PyNumber_Invert (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the bitwise negation of 'o' on success, or ‘NULL’ on
     failure.  This is the equivalent of the Python expression ‘~o’.

 -- C Function: *note PyObject: 33a. *PyNumber_Lshift (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of left shifting 'o1' by 'o2' on success,
     or ‘NULL’ on failure.  This is the equivalent of the Python
     expression ‘o1 << o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Rshift (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of right shifting 'o1' by 'o2' on
     success, or ‘NULL’ on failure.  This is the equivalent of the
     Python expression ‘o1 >> o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_And (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise and” of 'o1' and 'o2' on success and
     ‘NULL’ on failure.  This is the equivalent of the Python expression
     ‘o1 & o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Xor (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise exclusive or” of 'o1' by 'o2' on
     success, or ‘NULL’ on failure.  This is the equivalent of the
     Python expression ‘o1 ^ o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Or (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise or” of 'o1' and 'o2' on success, or
     ‘NULL’ on failure.  This is the equivalent of the Python expression
     ‘o1 | o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceAdd (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of adding 'o1' and 'o2', or ‘NULL’ on
     failure.  The operation is done 'in-place' when 'o1' supports it.
     This is the equivalent of the Python statement ‘o1 += o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceSubtract (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of subtracting 'o2' from 'o1', or ‘NULL’
     on failure.  The operation is done 'in-place' when 'o1' supports
     it.  This is the equivalent of the Python statement ‘o1 -= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceMultiply (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of multiplying 'o1' and 'o2', or ‘NULL’
     on failure.  The operation is done 'in-place' when 'o1' supports
     it.  This is the equivalent of the Python statement ‘o1 *= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceMatrixMultiply
          (PyObject *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Returns the result of matrix multiplication on
     'o1' and 'o2', or ‘NULL’ on failure.  The operation is done
     'in-place' when 'o1' supports it.  This is the equivalent of the
     Python statement ‘o1 @= o2’.

     Added in version 3.5.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceFloorDivide
          (PyObject *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the mathematical floor of dividing 'o1' by 'o2', or
     ‘NULL’ on failure.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python statement ‘o1
     //= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceTrueDivide
          (PyObject *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a reasonable approximation for the mathematical value
     of 'o1' divided by 'o2', or ‘NULL’ on failure.  The return value is
     “approximate” because binary floating-point numbers are
     approximate; it is not possible to represent all real numbers in
     base two.  This function can return a floating-point value when
     passed two integers.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python statement ‘o1 /=
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceRemainder
          (PyObject *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the remainder of dividing 'o1' by 'o2', or ‘NULL’ on
     failure.  The operation is done 'in-place' when 'o1' supports it.
     This is the equivalent of the Python statement ‘o1 %= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlacePower (PyObject
          *o1, PyObject *o2, PyObject *o3)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     See the built-in function *note pow(): 9dd.  Returns ‘NULL’ on
     failure.  The operation is done 'in-place' when 'o1' supports it.
     This is the equivalent of the Python statement ‘o1 **= o2’ when o3
     is *note Py_None: 4b69, or an in-place variant of ‘pow(o1, o2, o3)’
     otherwise.  If 'o3' is to be ignored, pass ‘Py_None’ in its place
     (passing ‘NULL’ for 'o3' would cause an illegal memory access).

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceLshift (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of left shifting 'o1' by 'o2' on success,
     or ‘NULL’ on failure.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python statement ‘o1
     <<= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceRshift (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the result of right shifting 'o1' by 'o2' on
     success, or ‘NULL’ on failure.  The operation is done 'in-place'
     when 'o1' supports it.  This is the equivalent of the Python
     statement ‘o1 >>= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceAnd (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise and” of 'o1' and 'o2' on success and
     ‘NULL’ on failure.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python statement ‘o1 &=
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceXor (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise exclusive or” of 'o1' by 'o2' on
     success, or ‘NULL’ on failure.  The operation is done 'in-place'
     when 'o1' supports it.  This is the equivalent of the Python
     statement ‘o1 ^= o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_InPlaceOr (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the “bitwise or” of 'o1' and 'o2' on success, or
     ‘NULL’ on failure.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python statement ‘o1 |=
     o2’.

 -- C Function: *note PyObject: 33a. *PyNumber_Long (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Returns the 'o' converted to an integer object on success, or
     ‘NULL’ on failure.  This is the equivalent of the Python expression
     ‘int(o)’.

 -- C Function: *note PyObject: 33a. *PyNumber_Float (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Returns the 'o' converted to a float object on success, or ‘NULL’
     on failure.  This is the equivalent of the Python expression
     ‘float(o)’.

 -- C Function: *note PyObject: 33a. *PyNumber_Index (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the 'o' converted to a Python int on success or
     ‘NULL’ with a *note TypeError: 2c3. exception raised on failure.

     Changed in version 3.10: The result always has exact type *note
     int: 257.  Previously, the result could have been an instance of a
     subclass of ‘int’.

 -- C Function: *note PyObject: 33a. *PyNumber_ToBase (PyObject *n, int
          base)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Returns the integer 'n' converted to base 'base' as a
     string.  The 'base' argument must be one of 2, 8, 10, or 16.  For
     base 2, 8, or 16, the returned string is prefixed with a base
     marker of ‘'0b'’, ‘'0o'’, or ‘'0x'’, respectively.  If 'n' is not a
     Python int, it is converted with *note PyNumber_Index(): 89a.
     first.

 -- C Function: *note Py_ssize_t: a6e. PyNumber_AsSsize_t (PyObject *o,
          PyObject *exc)
     ' Part of the *note Stable ABI: 556.'  Returns 'o' converted to a
     *note Py_ssize_t: a6e. value if 'o' can be interpreted as an
     integer.  If the call fails, an exception is raised and ‘-1’ is
     returned.

     If 'o' can be converted to a Python int but the attempt to convert
     to a *note Py_ssize_t: a6e. value would raise an *note
     OverflowError: 888, then the 'exc' argument is the type of
     exception that will be raised (usually *note IndexError: 1585. or
     ‘OverflowError’).  If 'exc' is ‘NULL’, then the exception is
     cleared and the value is clipped to ‘PY_SSIZE_T_MIN’ for a negative
     integer or ‘PY_SSIZE_T_MAX’ for a positive integer.

 -- C Function: int PyIndex_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556. since version 3.8.'  Returns
     ‘1’ if 'o' is an index integer (has the ‘nb_index’ slot of the
     ‘tp_as_number’ structure filled in), and ‘0’ otherwise.  This
     function always succeeds.


File: python.info,  Node: Sequence Protocol,  Next: Mapping Protocol,  Prev: Number Protocol,  Up: Abstract Objects Layer

7.7.4 Sequence Protocol
-----------------------

 -- C Function: int PySequence_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if the object
     provides the sequence protocol, and ‘0’ otherwise.  Note that it
     returns ‘1’ for Python classes with a *note __getitem__(): 283.
     method, unless they are *note dict: 256. subclasses, since in
     general it is impossible to determine what type of keys the class
     supports.  This function always succeeds.

 -- C Function: *note Py_ssize_t: a6e. PySequence_Size (PyObject *o)
 -- C Function: *note Py_ssize_t: a6e. PySequence_Length (PyObject *o)
     ' Part of the *note Stable ABI: 556.'

     Returns the number of objects in sequence 'o' on success, and ‘-1’
     on failure.  This is equivalent to the Python expression ‘len(o)’.

 -- C Function: *note PyObject: 33a. *PySequence_Concat (PyObject *o1,
          PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the concatenation of 'o1' and 'o2' on success, and
     ‘NULL’ on failure.  This is the equivalent of the Python expression
     ‘o1 + o2’.

 -- C Function: *note PyObject: 33a. *PySequence_Repeat (PyObject *o,
          Py_ssize_t count)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the result of repeating sequence object 'o' 'count'
     times, or ‘NULL’ on failure.  This is the equivalent of the Python
     expression ‘o * count’.

 -- C Function: *note PyObject: 33a. *PySequence_InPlaceConcat (PyObject
          *o1, PyObject *o2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the concatenation of 'o1' and 'o2' on success, and
     ‘NULL’ on failure.  The operation is done 'in-place' when 'o1'
     supports it.  This is the equivalent of the Python expression ‘o1
     += o2’.

 -- C Function: *note PyObject: 33a. *PySequence_InPlaceRepeat (PyObject
          *o, Py_ssize_t count)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the result of repeating sequence object 'o' 'count'
     times, or ‘NULL’ on failure.  The operation is done 'in-place' when
     'o' supports it.  This is the equivalent of the Python expression
     ‘o *= count’.

 -- C Function: *note PyObject: 33a. *PySequence_GetItem (PyObject *o,
          Py_ssize_t i)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the 'i'th element of 'o', or ‘NULL’ on failure.  This
     is the equivalent of the Python expression ‘o[i]’.

 -- C Function: *note PyObject: 33a. *PySequence_GetSlice (PyObject *o,
          Py_ssize_t i1, Py_ssize_t i2)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the slice of sequence object 'o' between 'i1' and
     'i2', or ‘NULL’ on failure.  This is the equivalent of the Python
     expression ‘o[i1:i2]’.

 -- C Function: int PySequence_SetItem (PyObject *o, Py_ssize_t i,
          PyObject *v)
     ' Part of the *note Stable ABI: 556.'  Assign object 'v' to the
     'i'th element of 'o'.  Raise an exception and return ‘-1’ on
     failure; return ‘0’ on success.  This is the equivalent of the
     Python statement ‘o[i] = v’.  This function 'does not' steal a
     reference to 'v'.

     If 'v' is ‘NULL’, the element is deleted, but this feature is
     deprecated in favour of using *note PySequence_DelItem(): 1be7.

 -- C Function: int PySequence_DelItem (PyObject *o, Py_ssize_t i)
     ' Part of the *note Stable ABI: 556.'  Delete the 'i'th element of
     object 'o'.  Returns ‘-1’ on failure.  This is the equivalent of
     the Python statement ‘del o[i]’.

 -- C Function: int PySequence_SetSlice (PyObject *o, Py_ssize_t i1,
          Py_ssize_t i2, PyObject *v)
     ' Part of the *note Stable ABI: 556.'  Assign the sequence object
     'v' to the slice in sequence object 'o' from 'i1' to 'i2'.  This is
     the equivalent of the Python statement ‘o[i1:i2] = v’.

 -- C Function: int PySequence_DelSlice (PyObject *o, Py_ssize_t i1,
          Py_ssize_t i2)
     ' Part of the *note Stable ABI: 556.'  Delete the slice in sequence
     object 'o' from 'i1' to 'i2'.  Returns ‘-1’ on failure.  This is
     the equivalent of the Python statement ‘del o[i1:i2]’.

 -- C Function: *note Py_ssize_t: a6e. PySequence_Count (PyObject *o,
          PyObject *value)
     ' Part of the *note Stable ABI: 556.'  Return the number of
     occurrences of 'value' in 'o', that is, return the number of keys
     for which ‘o[key] == value’.  On failure, return ‘-1’.  This is
     equivalent to the Python expression ‘o.count(value)’.

 -- C Function: int PySequence_Contains (PyObject *o, PyObject *value)
     ' Part of the *note Stable ABI: 556.'  Determine if 'o' contains
     'value'.  If an item in 'o' is equal to 'value', return ‘1’,
     otherwise return ‘0’.  On error, return ‘-1’.  This is equivalent
     to the Python expression ‘value in o’.

 -- C Function: *note Py_ssize_t: a6e. PySequence_Index (PyObject *o,
          PyObject *value)
     ' Part of the *note Stable ABI: 556.'  Return the first index 'i'
     for which ‘o[i] == value’.  On error, return ‘-1’.  This is
     equivalent to the Python expression ‘o.index(value)’.

 -- C Function: *note PyObject: 33a. *PySequence_List (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a list object with the same contents as the sequence
     or iterable 'o', or ‘NULL’ on failure.  The returned list is
     guaranteed to be new.  This is equivalent to the Python expression
     ‘list(o)’.

 -- C Function: *note PyObject: 33a. *PySequence_Tuple (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Return a tuple object with the same contents as the sequence or
     iterable 'o', or ‘NULL’ on failure.  If 'o' is a tuple, a new
     reference will be returned, otherwise a tuple will be constructed
     with the appropriate contents.  This is equivalent to the Python
     expression ‘tuple(o)’.

 -- C Function: *note PyObject: 33a. *PySequence_Fast (PyObject *o,
          const char *m)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the sequence or iterable 'o' as an object usable by
     the other ‘PySequence_Fast*’ family of functions.  If the object is
     not a sequence or iterable, raises *note TypeError: 2c3. with 'm'
     as the message text.  Returns ‘NULL’ on failure.

     The ‘PySequence_Fast*’ functions are thus named because they assume
     'o' is a *note PyTupleObject: 4ed5. or a *note PyListObject: 4f58.
     and access the data fields of 'o' directly.

     As a CPython implementation detail, if 'o' is already a sequence or
     list, it will be returned.

 -- C Function: *note Py_ssize_t: a6e. PySequence_Fast_GET_SIZE
          (PyObject *o)

     Returns the length of 'o', assuming that 'o' was returned by *note
     PySequence_Fast(): 4d6b. and that 'o' is not ‘NULL’.  The size can
     also be retrieved by calling *note PySequence_Size(): 1be4. on 'o',
     but *note PySequence_Fast_GET_SIZE(): 4f59. is faster because it
     can assume 'o' is a list or tuple.

 -- C Function: *note PyObject: 33a. *PySequence_Fast_GET_ITEM (PyObject
          *o, Py_ssize_t i)
     'Return value: Borrowed reference.'  Return the 'i'th element of
     'o', assuming that 'o' was returned by *note PySequence_Fast():
     4d6b, 'o' is not ‘NULL’, and that 'i' is within bounds.

 -- C Function: *note PyObject: 33a. **PySequence_Fast_ITEMS (PyObject
          *o)

     Return the underlying array of PyObject pointers.  Assumes that 'o'
     was returned by *note PySequence_Fast(): 4d6b. and 'o' is not
     ‘NULL’.

     Note, if a list gets resized, the reallocation may relocate the
     items array.  So, only use the underlying array pointer in contexts
     where the sequence cannot change.

 -- C Function: *note PyObject: 33a. *PySequence_ITEM (PyObject *o,
          Py_ssize_t i)
     'Return value: New reference.'  Return the 'i'th element of 'o' or
     ‘NULL’ on failure.  Faster form of *note PySequence_GetItem():
     1be5. but without checking that *note PySequence_Check(): 4d66. on
     'o' is true and without adjustment for negative indices.


File: python.info,  Node: Mapping Protocol,  Next: Iterator Protocol,  Prev: Sequence Protocol,  Up: Abstract Objects Layer

7.7.5 Mapping Protocol
----------------------

See also *note PyObject_GetItem(): 348, *note PyObject_SetItem(): 4c0a.
and *note PyObject_DelItem(): 4d50.

 -- C Function: int PyMapping_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if the object
     provides the mapping protocol or supports slicing, and ‘0’
     otherwise.  Note that it returns ‘1’ for Python classes with a
     *note __getitem__(): 283. method, since in general it is impossible
     to determine what type of keys the class supports.  This function
     always succeeds.

 -- C Function: *note Py_ssize_t: a6e. PyMapping_Size (PyObject *o)
 -- C Function: *note Py_ssize_t: a6e. PyMapping_Length (PyObject *o)
     ' Part of the *note Stable ABI: 556.'

     Returns the number of keys in object 'o' on success, and ‘-1’ on
     failure.  This is equivalent to the Python expression ‘len(o)’.

 -- C Function: *note PyObject: 33a. *PyMapping_GetItemString (PyObject
          *o, const char *key)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  This is the same as *note PyObject_GetItem(): 348, but 'key'
     is specified as a const char* UTF-8 encoded bytes string, rather
     than a *note PyObject: 33a.*.

 -- C Function: int PyMapping_GetOptionalItem (PyObject *obj, PyObject
          *key, PyObject **result)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Variant
     of *note PyObject_GetItem(): 348. which doesn’t raise *note
     KeyError: 345. if the key is not found.

     If the key is found, return ‘1’ and set '*result' to a new *note
     strong reference: 33e. to the corresponding value.  If the key is
     not found, return ‘0’ and set '*result' to ‘NULL’; the *note
     KeyError: 345. is silenced.  If an error other than ‘KeyError’ is
     raised, return ‘-1’ and set '*result' to ‘NULL’.

     Added in version 3.13.

 -- C Function: int PyMapping_GetOptionalItemString (PyObject *obj,
          const char *key, PyObject **result)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  This is
     the same as *note PyMapping_GetOptionalItem(): 346, but 'key' is
     specified as a const char* UTF-8 encoded bytes string, rather than
     a *note PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: int PyMapping_SetItemString (PyObject *o, const char
          *key, PyObject *v)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyObject_SetItem(): 4c0a, but 'key' is specified as a const char*
     UTF-8 encoded bytes string, rather than a *note PyObject: 33a.*.

 -- C Function: int PyMapping_DelItem (PyObject *o, PyObject *key)

     This is an alias of *note PyObject_DelItem(): 4d50.

 -- C Function: int PyMapping_DelItemString (PyObject *o, const char
          *key)

     This is the same as *note PyObject_DelItem(): 4d50, but 'key' is
     specified as a const char* UTF-8 encoded bytes string, rather than
     a *note PyObject: 33a.*.

 -- C Function: int PyMapping_HasKeyWithError (PyObject *o, PyObject
          *key)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Return
     ‘1’ if the mapping object has the key 'key' and ‘0’ otherwise.
     This is equivalent to the Python expression ‘key in o’.  On
     failure, return ‘-1’.

     Added in version 3.13.

 -- C Function: int PyMapping_HasKeyStringWithError (PyObject *o, const
          char *key)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  This is
     the same as *note PyMapping_HasKeyWithError(): 381, but 'key' is
     specified as a const char* UTF-8 encoded bytes string, rather than
     a *note PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: int PyMapping_HasKey (PyObject *o, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if the mapping
     object has the key 'key' and ‘0’ otherwise.  This is equivalent to
     the Python expression ‘key in o’.  This function always succeeds.

          Note: Exceptions which occur when this calls the *note
          __getitem__(): 283. method are silently ignored.  For proper
          error handling, use *note PyMapping_HasKeyWithError(): 381,
          *note PyMapping_GetOptionalItem(): 346. or *note
          PyObject_GetItem(): 348. instead.

 -- C Function: int PyMapping_HasKeyString (PyObject *o, const char
          *key)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyMapping_HasKey(): 382, but 'key' is specified as a const char*
     UTF-8 encoded bytes string, rather than a *note PyObject: 33a.*.

          Note: Exceptions that occur when this calls the *note
          __getitem__(): 283. method or while creating the temporary
          *note str: 44f. object are silently ignored.  For proper error
          handling, use *note PyMapping_HasKeyStringWithError(): 383,
          *note PyMapping_GetOptionalItemString(): 347. or *note
          PyMapping_GetItemString(): 349. instead.

 -- C Function: *note PyObject: 33a. *PyMapping_Keys (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  On success, return a list of the keys in object 'o'.  On
     failure, return ‘NULL’.

     Changed in version 3.7: Previously, the function returned a list or
     a tuple.

 -- C Function: *note PyObject: 33a. *PyMapping_Values (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  On success, return a list of the values in object 'o'.  On
     failure, return ‘NULL’.

     Changed in version 3.7: Previously, the function returned a list or
     a tuple.

 -- C Function: *note PyObject: 33a. *PyMapping_Items (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  On success, return a list of the items in object 'o', where
     each item is a tuple containing a key-value pair.  On failure,
     return ‘NULL’.

     Changed in version 3.7: Previously, the function returned a list or
     a tuple.


File: python.info,  Node: Iterator Protocol,  Next: Buffer Protocol,  Prev: Mapping Protocol,  Up: Abstract Objects Layer

7.7.6 Iterator Protocol
-----------------------

There are two functions specifically for working with iterators.

 -- C Function: int PyIter_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556. since version 3.8.'  Return
     non-zero if the object 'o' can be safely passed to *note
     PyIter_Next(): 4cff, and ‘0’ otherwise.  This function always
     succeeds.

 -- C Function: int PyAIter_Check (PyObject *o)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Return
     non-zero if the object 'o' provides the ‘AsyncIterator’ protocol,
     and ‘0’ otherwise.  This function always succeeds.

     Added in version 3.10.

 -- C Function: *note PyObject: 33a. *PyIter_Next (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the next value from the iterator 'o'.  The object
     must be an iterator according to *note PyIter_Check(): 1a58. (it is
     up to the caller to check this).  If there are no remaining values,
     returns ‘NULL’ with no exception set.  If an error occurs while
     retrieving the item, returns ‘NULL’ and passes along the exception.

To write a loop which iterates over an iterator, the C code should look
something like this:

     PyObject *iterator = PyObject_GetIter(obj);
     PyObject *item;

     if (iterator == NULL) {
         /* propagate error */
     }

     while ((item = PyIter_Next(iterator))) {
         /* do something with item */
         ...
         /* release reference when done */
         Py_DECREF(item);
     }

     Py_DECREF(iterator);

     if (PyErr_Occurred()) {
         /* propagate error */
     }
     else {
         /* continue doing useful work */
     }

 -- C Type: type PySendResult

     The enum value used to represent different results of *note
     PyIter_Send(): 89f.

     Added in version 3.10.

 -- C Function: *note PySendResult: 4f67. PyIter_Send (PyObject *iter,
          PyObject *arg, PyObject **presult)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Sends
     the 'arg' value into the iterator 'iter'.  Returns:

        - ‘PYGEN_RETURN’ if iterator returns.  Return value is returned
          via 'presult'.

        - ‘PYGEN_NEXT’ if iterator yields.  Yielded value is returned
          via 'presult'.

        - ‘PYGEN_ERROR’ if iterator has raised and exception.  'presult'
          is set to ‘NULL’.

     Added in version 3.10.


File: python.info,  Node: Buffer Protocol,  Prev: Iterator Protocol,  Up: Abstract Objects Layer

7.7.7 Buffer Protocol
---------------------

Certain objects available in Python wrap access to an underlying memory
array or 'buffer'.  Such objects include the built-in *note bytes: 1c2.
and *note bytearray: 2ea, and some extension types like *note
array.array: 1a0.  Third-party libraries may define their own types for
special purposes, such as image processing or numeric analysis.

While each of these types have their own semantics, they share the
common characteristic of being backed by a possibly large memory buffer.
It is then desirable, in some situations, to access that buffer directly
and without intermediate copying.

Python provides such a facility at the C and Python level in the form of
the *note buffer protocol: 2e8.  This protocol has two sides:

   - on the producer side, a type can export a “buffer interface” which
     allows objects of that type to expose information about their
     underlying buffer.  This interface is described in the section
     *note Buffer Object Structures: 4f6b.; for Python see *note
     Emulating buffer types: 2175.

   - on the consumer side, several means are available to obtain a
     pointer to the raw underlying data of an object (for example a
     method parameter).  For Python see *note memoryview: 2eb.

Simple objects such as *note bytes: 1c2. and *note bytearray: 2ea.
expose their underlying buffer in byte-oriented form.  Other forms are
possible; for example, the elements exposed by an *note array.array:
1a0. can be multi-byte values.

An example consumer of the buffer interface is the *note write(): d02.
method of file objects: any object that can export a series of bytes
through the buffer interface can be written to a file.  While ‘write()’
only needs read-only access to the internal contents of the object
passed to it, other methods such as *note readinto(): 2e13. need write
access to the contents of their argument.  The buffer interface allows
objects to selectively allow or reject exporting of read-write and
read-only buffers.

There are two ways for a consumer of the buffer interface to acquire a
buffer over a target object:

   * call *note PyObject_GetBuffer(): 39c. with the right parameters;

   * call *note PyArg_ParseTuple(): 574. (or one of its siblings) with
     one of the ‘y*’, ‘w*’ or ‘s*’ *note format codes: 8b0.

In both cases, *note PyBuffer_Release(): 39d. must be called when the
buffer isn’t needed anymore.  Failure to do so could lead to various
issues such as resource leaks.

Added in version 3.12: The buffer protocol is now accessible in Python,
see *note Emulating buffer types: 2175. and *note memoryview: 2eb.

* Menu:

* Buffer structure::
* Buffer request types::
* Complex arrays::
* Buffer-related functions::


File: python.info,  Node: Buffer structure,  Next: Buffer request types,  Up: Buffer Protocol

7.7.7.1 Buffer structure
........................

Buffer structures (or simply “buffers”) are useful as a way to expose
the binary data from another object to the Python programmer.  They can
also be used as a zero-copy slicing mechanism.  Using their ability to
reference a block of memory, it is possible to expose any data to the
Python programmer quite easily.  The memory could be a large, constant
array in a C extension, it could be a raw block of memory for
manipulation before passing to an operating system library, or it could
be used to pass around structured data in its native, in-memory format.

Contrary to most data types exposed by the Python interpreter, buffers
are not *note PyObject: 33a. pointers but rather simple C structures.
This allows them to be created and copied very simply.  When a generic
wrapper around a buffer is needed, a *note memoryview: 4f6e. object can
be created.

For short instructions how to write an exporting object, see *note
Buffer Object Structures: 4f6b.  For obtaining a buffer, see *note
PyObject_GetBuffer(): 39c.

 -- C Type: type Py_buffer
     ' Part of the *note Stable ABI: 556. (including all members) since
     version 3.11.'
      -- C Member: void *buf

          A pointer to the start of the logical structure described by
          the buffer fields.  This can be any location within the
          underlying physical memory block of the exporter.  For
          example, with negative *note strides: 4f70. the value may
          point to the end of the memory block.

          For *note contiguous: 23dc. arrays, the value points to the
          beginning of the memory block.

      -- C Member: *note PyObject: 33a. *obj

          A new reference to the exporting object.  The reference is
          owned by the consumer and automatically released (i.e.
          reference count decremented) and set to ‘NULL’ by *note
          PyBuffer_Release(): 39d.  The field is the equivalent of the
          return value of any standard C-API function.

          As a special case, for 'temporary' buffers that are wrapped by
          *note PyMemoryView_FromBuffer(): 764. or *note
          PyBuffer_FillInfo(): 763. this field is ‘NULL’.  In general,
          exporting objects MUST NOT use this scheme.

      -- C Member: *note Py_ssize_t: a6e. len

          ‘product(shape) * itemsize’.  For contiguous arrays, this is
          the length of the underlying memory block.  For non-contiguous
          arrays, it is the length that the logical structure would have
          if it were copied to a contiguous representation.

          Accessing ‘((char *)buf)[0] up to ((char *)buf)[len-1]’ is
          only valid if the buffer has been obtained by a request that
          guarantees contiguity.  In most cases such a request will be
          *note PyBUF_SIMPLE: 4c33. or *note PyBUF_WRITABLE: 1402.

      -- C Member: int readonly

          An indicator of whether the buffer is read-only.  This field
          is controlled by the *note PyBUF_WRITABLE: 1402. flag.

      -- C Member: *note Py_ssize_t: a6e. itemsize

          Item size in bytes of a single element.  Same as the value of
          *note struct.calcsize(): 1b54. called on non-‘NULL’ *note
          format: 4f75. values.

          Important exception: If a consumer requests a buffer without
          the *note PyBUF_FORMAT: 4c2b. flag, *note format: 4f75. will
          be set to ‘NULL’, but *note itemsize: 4f74. still has the
          value for the original format.

          If *note shape: 4f76. is present, the equality ‘product(shape)
          * itemsize == len’ still holds and the consumer can use *note
          itemsize: 4f74. to navigate the buffer.

          If *note shape: 4f76. is ‘NULL’ as a result of a *note
          PyBUF_SIMPLE: 4c33. or a *note PyBUF_WRITABLE: 1402. request,
          the consumer must disregard *note itemsize: 4f74. and assume
          ‘itemsize == 1’.

      -- C Member: char *format

          A 'NULL' terminated string in *note struct: d5. module style
          syntax describing the contents of a single item.  If this is
          ‘NULL’, ‘"B"’ (unsigned bytes) is assumed.

          This field is controlled by the *note PyBUF_FORMAT: 4c2b.
          flag.

      -- C Member: int ndim

          The number of dimensions the memory represents as an
          n-dimensional array.  If it is ‘0’, *note buf: 4f6f. points to
          a single item representing a scalar.  In this case, *note
          shape: 4f76, *note strides: 4f70. and *note suboffsets: 4f78.
          MUST be ‘NULL’.  The maximum number of dimensions is given by
          *note PyBUF_MAX_NDIM: 4c2f.

      -- C Member: *note Py_ssize_t: a6e. *shape

          An array of *note Py_ssize_t: a6e. of length *note ndim: 4f77.
          indicating the shape of the memory as an n-dimensional array.
          Note that ‘shape[0] * ... * shape[ndim-1] * itemsize’ MUST be
          equal to *note len: 4f72.

          Shape values are restricted to ‘shape[n] >= 0’.  The case
          ‘shape[n] == 0’ requires special attention.  See *note complex
          arrays: 4f79. for further information.

          The shape array is read-only for the consumer.

      -- C Member: *note Py_ssize_t: a6e. *strides

          An array of *note Py_ssize_t: a6e. of length *note ndim: 4f77.
          giving the number of bytes to skip to get to a new element in
          each dimension.

          Stride values can be any integer.  For regular arrays, strides
          are usually positive, but a consumer MUST be able to handle
          the case ‘strides[n] <= 0’.  See *note complex arrays: 4f79.
          for further information.

          The strides array is read-only for the consumer.

      -- C Member: *note Py_ssize_t: a6e. *suboffsets

          An array of *note Py_ssize_t: a6e. of length *note ndim: 4f77.
          If ‘suboffsets[n] >= 0’, the values stored along the nth
          dimension are pointers and the suboffset value dictates how
          many bytes to add to each pointer after de-referencing.  A
          suboffset value that is negative indicates that no
          de-referencing should occur (striding in a contiguous memory
          block).

          If all suboffsets are negative (i.e.  no de-referencing is
          needed), then this field must be ‘NULL’ (the default value).

          This type of array representation is used by the Python
          Imaging Library (PIL). See *note complex arrays: 4f79. for
          further information how to access elements of such an array.

          The suboffsets array is read-only for the consumer.

      -- C Member: void *internal

          This is for use internally by the exporting object.  For
          example, this might be re-cast as an integer by the exporter
          and used to store flags about whether or not the shape,
          strides, and suboffsets arrays must be freed when the buffer
          is released.  The consumer MUST NOT alter this value.

Constants:

 -- C Macro: PyBUF_MAX_NDIM
     ' Part of the *note Stable ABI: 556. since version 3.11.'  The
     maximum number of dimensions the memory represents.  Exporters MUST
     respect this limit, consumers of multi-dimensional buffers SHOULD
     be able to handle up to ‘PyBUF_MAX_NDIM’ dimensions.  Currently set
     to 64.


File: python.info,  Node: Buffer request types,  Next: Complex arrays,  Prev: Buffer structure,  Up: Buffer Protocol

7.7.7.2 Buffer request types
............................

Buffers are usually obtained by sending a buffer request to an exporting
object via *note PyObject_GetBuffer(): 39c.  Since the complexity of the
logical structure of the memory can vary drastically, the consumer uses
the 'flags' argument to specify the exact buffer type it can handle.

All *note Py_buffer: 75b. fields are unambiguously defined by the
request type.

* Menu:

* request-independent fields::
* readonly, format: readonly format.
* shape, strides, suboffsets: shape strides suboffsets.
* contiguity requests::
* compound requests::


File: python.info,  Node: request-independent fields,  Next: readonly format,  Up: Buffer request types

7.7.7.3 request-independent fields
..................................

The following fields are not influenced by 'flags' and must always be
filled in with the correct values: *note obj: 4f71, *note buf: 4f6f,
*note len: 4f72, *note itemsize: 4f74, *note ndim: 4f77.


File: python.info,  Node: readonly format,  Next: shape strides suboffsets,  Prev: request-independent fields,  Up: Buffer request types

7.7.7.4 readonly, format
........................

      -- C Macro: PyBUF_WRITABLE
          ' Part of the *note Stable ABI: 556. since version 3.11.'
          Controls the *note readonly: 4f73. field.  If set, the
          exporter MUST provide a writable buffer or else report
          failure.  Otherwise, the exporter MAY provide either a
          read-only or writable buffer, but the choice MUST be
          consistent for all consumers.  For example, *note
          PyBUF_SIMPLE: 4c33. | *note PyBUF_WRITABLE: 1402. can be used
          to request a simple writable buffer.

      -- C Macro: PyBUF_WRITEABLE

          This is a *note soft deprecated: 209. alias to *note
          PyBUF_WRITABLE: 1402.

      -- C Macro: PyBUF_FORMAT
          ' Part of the *note Stable ABI: 556. since version 3.11.'
          Controls the *note format: 4f75. field.  If set, this field
          MUST be filled in correctly.  Otherwise, this field MUST be
          ‘NULL’.

*note PyBUF_WRITABLE: 1402. can be |’d to any of the flags in the next
section.  Since *note PyBUF_SIMPLE: 4c33. is defined as 0,
‘PyBUF_WRITABLE’ can be used as a stand-alone flag to request a simple
writable buffer.

*note PyBUF_FORMAT: 4c2b. must be |’d to any of the flags except *note
PyBUF_SIMPLE: 4c33, because the latter already implies format ‘B’
(unsigned bytes).  ‘PyBUF_FORMAT’ cannot be used on its own.


File: python.info,  Node: shape strides suboffsets,  Next: contiguity requests,  Prev: readonly format,  Up: Buffer request types

7.7.7.5 shape, strides, suboffsets
..................................

The flags that control the logical structure of the memory are listed in
decreasing order of complexity.  Note that each flag contains all bits
of the flags below it.

Request                           shape       strides       suboffsets
                                                            
-----------------------------------------------------------------------------
                                                            
 -- C Macro: PyBUF_INDIRECT       yes         yes           if needed
     ' Part of the                                          
     *note Stable ABI: 556.
     since version 3.11.'

 -- C Macro: PyBUF_STRIDES        yes         yes           NULL
     ' Part of the                                          
     *note Stable ABI: 556.
     since version 3.11.'

 -- C Macro: PyBUF_ND             yes         NULL          NULL
     ' Part of the                                          
     *note Stable ABI: 556.
     since version 3.11.'

 -- C Macro: PyBUF_SIMPLE         NULL        NULL          NULL
     ' Part of the                                          
     *note Stable ABI: 556.
     since version 3.11.'


File: python.info,  Node: contiguity requests,  Next: compound requests,  Prev: shape strides suboffsets,  Up: Buffer request types

7.7.7.6 contiguity requests
...........................

C or Fortran *note contiguity: 23dc. can be explicitly requested, with
and without stride information.  Without stride information, the buffer
must be C-contiguous.

Request                                 shape       strides       suboffsets       contig
                                                                                   
------------------------------------------------------------------------------------------------
                                                                                   
 -- C Macro: PyBUF_C_CONTIGUOUS         yes         yes           NULL             C
     ' Part of the                                                                 
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_F_CONTIGUOUS         yes         yes           NULL             F
     ' Part of the                                                                 
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_ANY_CONTIGUOUS       yes         yes           NULL             C or F
     ' Part of the                                                                 
     *note Stable ABI: 556. since
     version 3.11.'

*note PyBUF_ND: 4c30.                   yes         NULL          NULL             C
                                                                                   


File: python.info,  Node: compound requests,  Prev: contiguity requests,  Up: Buffer request types

7.7.7.7 compound requests
.........................

All possible requests are fully defined by some combination of the flags
in the previous section.  For convenience, the buffer protocol provides
frequently used combinations as single flags.

In the following table 'U' stands for undefined contiguity.  The
consumer would have to call *note PyBuffer_IsContiguous(): 761. to
determine contiguity.

Request                             shape       strides       suboffsets       contig       readonly       format
                                                                                                           
------------------------------------------------------------------------------------------------------------------------
                                                                                                           
 -- C Macro: PyBUF_FULL             yes         yes           if needed        U            0              yes
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_FULL_RO          yes         yes           if needed        U            1 or 0         yes
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_RECORDS          yes         yes           NULL             U            0              yes
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_RECORDS_RO       yes         yes           NULL             U            1 or 0         yes
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_STRIDED          yes         yes           NULL             U            0              NULL
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_STRIDED_RO       yes         yes           NULL             U            1 or 0         NULL
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_CONTIG           yes         NULL          NULL             C            0              NULL
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'

 -- C Macro: PyBUF_CONTIG_RO        yes         NULL          NULL             C            1 or 0         NULL
     ' Part of the                                                                                         
     *note Stable ABI: 556. since
     version 3.11.'


File: python.info,  Node: Complex arrays,  Next: Buffer-related functions,  Prev: Buffer request types,  Up: Buffer Protocol

7.7.7.8 Complex arrays
......................

* Menu:

* NumPy-style; shape and strides: NumPy-style shape and strides.
* PIL-style; shape, strides and suboffsets: PIL-style shape strides and suboffsets.


File: python.info,  Node: NumPy-style shape and strides,  Next: PIL-style shape strides and suboffsets,  Up: Complex arrays

7.7.7.9 NumPy-style: shape and strides
......................................

The logical structure of NumPy-style arrays is defined by *note
itemsize: 4f74, *note ndim: 4f77, *note shape: 4f76. and *note strides:
4f70.

If ‘ndim == 0’, the memory location pointed to by *note buf: 4f6f. is
interpreted as a scalar of size *note itemsize: 4f74.  In that case,
both *note shape: 4f76. and *note strides: 4f70. are ‘NULL’.

If *note strides: 4f70. is ‘NULL’, the array is interpreted as a
standard n-dimensional C-array.  Otherwise, the consumer must access an
n-dimensional array as follows:

     ptr = (char *)buf + indices[0] * strides[0] + ... + indices[n-1] * strides[n-1];
     item = *((typeof(item) *)ptr);

As noted above, *note buf: 4f6f. can point to any location within the
actual memory block.  An exporter can check the validity of a buffer
with this function:

     def verify_structure(memlen, itemsize, ndim, shape, strides, offset):
         """Verify that the parameters represent a valid array within
            the bounds of the allocated memory:
                char *mem: start of the physical memory block
                memlen: length of the physical memory block
                offset: (char *)buf - mem
         """
         if offset % itemsize:
             return False
         if offset < 0 or offset+itemsize > memlen:
             return False
         if any(v % itemsize for v in strides):
             return False

         if ndim <= 0:
             return ndim == 0 and not shape and not strides
         if 0 in shape:
             return True

         imin = sum(strides[j]*(shape[j]-1) for j in range(ndim)
                    if strides[j] <= 0)
         imax = sum(strides[j]*(shape[j]-1) for j in range(ndim)
                    if strides[j] > 0)

         return 0 <= offset+imin and offset+imax+itemsize <= memlen


File: python.info,  Node: PIL-style shape strides and suboffsets,  Prev: NumPy-style shape and strides,  Up: Complex arrays

7.7.7.10 PIL-style: shape, strides and suboffsets
.................................................

In addition to the regular items, PIL-style arrays can contain pointers
that must be followed in order to get to the next element in a
dimension.  For example, the regular three-dimensional C-array ‘char
v[2][2][3]’ can also be viewed as an array of 2 pointers to 2
two-dimensional arrays: ‘char (*v[2])[2][3]’.  In suboffsets
representation, those two pointers can be embedded at the start of *note
buf: 4f6f, pointing to two ‘char x[2][3]’ arrays that can be located
anywhere in memory.

Here is a function that returns a pointer to the element in an N-D array
pointed to by an N-dimensional index when there are both non-‘NULL’
strides and suboffsets:

     void *get_item_pointer(int ndim, void *buf, Py_ssize_t *strides,
                            Py_ssize_t *suboffsets, Py_ssize_t *indices) {
         char *pointer = (char*)buf;
         int i;
         for (i = 0; i < ndim; i++) {
             pointer += strides[i] * indices[i];
             if (suboffsets[i] >=0 ) {
                 pointer = *((char**)pointer) + suboffsets[i];
             }
         }
         return (void*)pointer;
     }


File: python.info,  Node: Buffer-related functions,  Prev: Complex arrays,  Up: Buffer Protocol

7.7.7.11 Buffer-related functions
.................................

 -- C Function: int PyObject_CheckBuffer (PyObject *obj)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Return
     ‘1’ if 'obj' supports the buffer interface otherwise ‘0’.  When ‘1’
     is returned, it doesn’t guarantee that *note PyObject_GetBuffer():
     39c. will succeed.  This function always succeeds.

 -- C Function: int PyObject_GetBuffer (PyObject *exporter, Py_buffer
          *view, int flags)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Send a
     request to 'exporter' to fill in 'view' as specified by 'flags'.
     If the exporter cannot provide a buffer of the exact type, it MUST
     raise *note BufferError: 15e3, set ‘view->obj’ to ‘NULL’ and return
     ‘-1’.

     On success, fill in 'view', set ‘view->obj’ to a new reference to
     'exporter' and return 0.  In the case of chained buffer providers
     that redirect requests to a single object, ‘view->obj’ MAY refer to
     this object instead of 'exporter' (See *note Buffer Object
     Structures: 4f6b.).

     Successful calls to *note PyObject_GetBuffer(): 39c. must be paired
     with calls to *note PyBuffer_Release(): 39d, similar to ‘malloc()’
     and ‘free()’.  Thus, after the consumer is done with the buffer,
     ‘PyBuffer_Release()’ must be called exactly once.

 -- C Function: void PyBuffer_Release (Py_buffer *view)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Release
     the buffer 'view' and release the *note strong reference: 33e.
     (i.e.  decrement the reference count) to the view’s supporting
     object, ‘view->obj’.  This function MUST be called when the buffer
     is no longer being used, otherwise reference leaks may occur.

     It is an error to call this function on a buffer that was not
     obtained via *note PyObject_GetBuffer(): 39c.

 -- C Function: *note Py_ssize_t: a6e. PyBuffer_SizeFromFormat (const
          char *format)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Return
     the implied *note itemsize: 4f74. from *note format: 4f75.  On
     error, raise an exception and return -1.

     Added in version 3.9.

 -- C Function: int PyBuffer_IsContiguous (const Py_buffer *view, char
          order)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Return
     ‘1’ if the memory defined by the 'view' is C-style ('order' is
     ‘'C'’) or Fortran-style ('order' is ‘'F'’) *note contiguous: 23dc.
     or either one ('order' is ‘'A'’).  Return ‘0’ otherwise.  This
     function always succeeds.

 -- C Function: void *PyBuffer_GetPointer (const Py_buffer *view, const
          Py_ssize_t *indices)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Get the
     memory area pointed to by the 'indices' inside the given 'view'.
     'indices' must point to an array of ‘view->ndim’ indices.

 -- C Function: int PyBuffer_FromContiguous (const Py_buffer *view,
          const void *buf, Py_ssize_t len, char fort)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Copy
     contiguous 'len' bytes from 'buf' to 'view'.  'fort' can be ‘'C'’
     or ‘'F'’ (for C-style or Fortran-style ordering).  ‘0’ is returned
     on success, ‘-1’ on error.

 -- C Function: int PyBuffer_ToContiguous (void *buf, const Py_buffer
          *src, Py_ssize_t len, char order)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Copy
     'len' bytes from 'src' to its contiguous representation in 'buf'.
     'order' can be ‘'C'’ or ‘'F'’ or ‘'A'’ (for C-style or
     Fortran-style ordering or either one).  ‘0’ is returned on success,
     ‘-1’ on error.

     This function fails if 'len' != 'src->len'.

 -- C Function: int PyObject_CopyData (PyObject *dest, PyObject *src)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Copy
     data from 'src' to 'dest' buffer.  Can convert between C-style and
     or Fortran-style buffers.

     ‘0’ is returned on success, ‘-1’ on error.

 -- C Function: void PyBuffer_FillContiguousStrides (int ndims,
          Py_ssize_t *shape, Py_ssize_t *strides, int itemsize, char
          order)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Fill the
     'strides' array with byte-strides of a *note contiguous: 23dc.
     (C-style if 'order' is ‘'C'’ or Fortran-style if 'order' is ‘'F'’)
     array of the given shape with the given number of bytes per
     element.

 -- C Function: int PyBuffer_FillInfo (Py_buffer *view, PyObject
          *exporter, void *buf, Py_ssize_t len, int readonly, int flags)
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Handle
     buffer requests for an exporter that wants to expose 'buf' of size
     'len' with writability set according to 'readonly'.  'buf' is
     interpreted as a sequence of unsigned bytes.

     The 'flags' argument indicates the request type.  This function
     always fills in 'view' as specified by flags, unless 'buf' has been
     designated as read-only and *note PyBUF_WRITABLE: 1402. is set in
     'flags'.

     On success, set ‘view->obj’ to a new reference to 'exporter' and
     return 0.  Otherwise, raise *note BufferError: 15e3, set
     ‘view->obj’ to ‘NULL’ and return ‘-1’;

     If this function is used as part of a *note getbufferproc: 4f6b,
     'exporter' MUST be set to the exporting object and 'flags' must be
     passed unmodified.  Otherwise, 'exporter' MUST be ‘NULL’.


File: python.info,  Node: Concrete Objects Layer,  Next: Initialization Finalization and Threads,  Prev: Abstract Objects Layer,  Up: Python/C API Reference Manual

7.8 Concrete Objects Layer
==========================

The functions in this chapter are specific to certain Python object
types.  Passing them an object of the wrong type is not a good idea; if
you receive an object from a Python program and you are not sure that it
has the right type, you must perform a type check first; for example, to
check that an object is a dictionary, use *note PyDict_Check(): 4f89.
The chapter is structured like the “family tree” of Python object types.

     Warning: While the functions described in this chapter carefully
     check the type of the objects which are passed in, many of them do
     not check for ‘NULL’ being passed instead of a valid object.
     Allowing ‘NULL’ to be passed in can cause memory access violations
     and immediate termination of the interpreter.

* Menu:

* Fundamental Objects::
* Numeric Objects::
* Sequence Objects::
* Container Objects::
* Function Objects: Function Objects<2>.
* Other Objects::
* C API for extension modules::


File: python.info,  Node: Fundamental Objects,  Next: Numeric Objects,  Up: Concrete Objects Layer

7.8.1 Fundamental Objects
-------------------------

This section describes Python type objects and the singleton object
‘None’.

* Menu:

* Type Objects: Type Objects<2>.
* The None Object::


File: python.info,  Node: Type Objects<2>,  Next: The None Object,  Up: Fundamental Objects

7.8.1.1 Type Objects
....................

 -- C Type: type PyTypeObject
     ' Part of the *note Limited API: 556. (as an opaque struct).'  The
     C structure of the objects used to describe built-in types.

 -- C Variable: *note PyTypeObject: aba. PyType_Type
     ' Part of the *note Stable ABI: 556.'  This is the type object for
     type objects; it is the same object as *note type: d71. in the
     Python layer.

 -- C Function: int PyType_Check (PyObject *o)

     Return non-zero if the object 'o' is a type object, including
     instances of types derived from the standard type object.  Return 0
     in all other cases.  This function always succeeds.

 -- C Function: int PyType_CheckExact (PyObject *o)

     Return non-zero if the object 'o' is a type object, but not a
     subtype of the standard type object.  Return 0 in all other cases.
     This function always succeeds.

 -- C Function: unsigned int PyType_ClearCache ()
     ' Part of the *note Stable ABI: 556.'  Clear the internal lookup
     cache.  Return the current version tag.

 -- C Function: unsigned long PyType_GetFlags (PyTypeObject *type)
     ' Part of the *note Stable ABI: 556.'  Return the *note tp_flags:
     1a18. member of 'type'.  This function is primarily meant for use
     with ‘Py_LIMITED_API’; the individual flag bits are guaranteed to
     be stable across Python releases, but access to ‘tp_flags’ itself
     is not part of the *note limited API: 399.

     Added in version 3.2.

     Changed in version 3.4: The return type is now ‘unsigned long’
     rather than ‘long’.

 -- C Function: *note PyObject: 33a. *PyType_GetDict (PyTypeObject
          *type)

     Return the type object’s internal namespace, which is otherwise
     only exposed via a read-only proxy (*note cls.__dict__: c7e.).
     This is a replacement for accessing *note tp_dict: 182b. directly.
     The returned dictionary must be treated as read-only.

     This function is meant for specific embedding and language-binding
     cases, where direct access to the dict is necessary and indirect
     access (e.g.  via the proxy or *note PyObject_GetAttr(): 34c.)
     isn’t adequate.

     Extension modules should continue to use ‘tp_dict’, directly or
     indirectly, when setting up their own types.

     Added in version 3.12.

 -- C Function: void PyType_Modified (PyTypeObject *type)
     ' Part of the *note Stable ABI: 556.'  Invalidate the internal
     lookup cache for the type and all of its subtypes.  This function
     must be called after any manual modification of the attributes or
     base classes of the type.

 -- C Function: int PyType_AddWatcher (PyType_WatchCallback callback)

     Register 'callback' as a type watcher.  Return a non-negative
     integer ID which must be passed to future calls to *note
     PyType_Watch(): 568.  In case of error (e.g.  no more watcher IDs
     available), return ‘-1’ and set an exception.

     In free-threaded builds, *note PyType_AddWatcher(): 567. is not
     thread-safe, so it must be called at start up (before spawning the
     first thread).

     Added in version 3.12.

 -- C Function: int PyType_ClearWatcher (int watcher_id)

     Clear watcher identified by 'watcher_id' (previously returned from
     *note PyType_AddWatcher(): 567.).  Return ‘0’ on success, ‘-1’ on
     error (e.g.  if 'watcher_id' was never registered.)

     An extension should never call ‘PyType_ClearWatcher’ with a
     'watcher_id' that was not returned to it by a previous call to
     *note PyType_AddWatcher(): 567.

     Added in version 3.12.

 -- C Function: int PyType_Watch (int watcher_id, PyObject *type)

     Mark 'type' as watched.  The callback granted 'watcher_id' by *note
     PyType_AddWatcher(): 567. will be called whenever *note
     PyType_Modified(): 1921. reports a change to 'type'.  (The callback
     may be called only once for a series of consecutive modifications
     to 'type', if ‘_PyType_Lookup()’ is not called on 'type' between
     the modifications; this is an implementation detail and subject to
     change.)

     An extension should never call ‘PyType_Watch’ with a 'watcher_id'
     that was not returned to it by a previous call to *note
     PyType_AddWatcher(): 567.

     Added in version 3.12.

 -- C Function: int PyType_Unwatch (int watcher_id, PyObject *type)

     Mark 'type' as not watched.  This undoes a previous call to *note
     PyType_Watch(): 568.  'type' must not be ‘NULL’.

     An extension should never call this function with a 'watcher_id'
     that was not returned to it by a previous call to *note
     PyType_AddWatcher(): 567.

     On success, this function returns ‘0’.  On failure, this function
     returns ‘-1’ with an exception set.

     Added in version 3.12.

 -- C Type: typedef int (*PyType_WatchCallback)(*note PyObject: 33a.
          *type)

     Type of a type-watcher callback function.

     The callback must not modify 'type' or cause *note
     PyType_Modified(): 1921. to be called on 'type' or any type in its
     MRO; violating this rule could cause infinite recursion.

     Added in version 3.12.

 -- C Function: int PyType_HasFeature (PyTypeObject *o, int feature)

     Return non-zero if the type object 'o' sets the feature 'feature'.
     Type features are denoted by single bit flags.

 -- C Function: int PyType_FastSubclass (PyTypeObject *type, int flag)

     Return non-zero if the type object 'type' sets the subclass flag
     'flag'.  Subclass flags are denoted by *note Py_TPFLAGS_*_SUBCLASS:
     4f93.  This function is used by many ‘_Check’ functions for common
     types.

     See also
     ........

     *note PyObject_TypeCheck(): 1a5b, which is used as a slower
     alternative in ‘_Check’ functions for types that don’t come with
     subclass flags.

 -- C Function: int PyType_IS_GC (PyTypeObject *o)

     Return true if the type object includes support for the cycle
     detector; this tests the type flag *note Py_TPFLAGS_HAVE_GC: 780.

 -- C Function: int PyType_IsSubtype (PyTypeObject *a, PyTypeObject *b)
     ' Part of the *note Stable ABI: 556.'  Return true if 'a' is a
     subtype of 'b'.

     This function only checks for actual subtypes, which means that
     *note __subclasscheck__(): 212d. is not called on 'b'.  Call *note
     PyObject_IsSubclass(): edb. to do the same check that *note
     issubclass(): 7c5. would do.

 -- C Function: *note PyObject: 33a. *PyType_GenericAlloc (PyTypeObject
          *type, Py_ssize_t nitems)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Generic handler for the *note tp_alloc: 4b9b. slot of a type
     object.  Use Python’s default memory allocation mechanism to
     allocate a new instance and initialize all its contents to ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyType_GenericNew (PyTypeObject
          *type, PyObject *args, PyObject *kwds)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Generic handler for the *note tp_new: 582. slot of a type
     object.  Create a new instance using the type’s *note tp_alloc:
     4b9b. slot.

 -- C Function: int PyType_Ready (PyTypeObject *type)
     ' Part of the *note Stable ABI: 556.'  Finalize a type object.
     This should be called on all type objects to finish their
     initialization.  This function is responsible for adding inherited
     slots from a type’s base class.  Return ‘0’ on success, or return
     ‘-1’ and sets an exception on error.

          Note: If some of the base classes implements the GC protocol
          and the provided type does not include the *note
          Py_TPFLAGS_HAVE_GC: 780. in its flags, then the GC protocol
          will be automatically implemented from its parents.  On the
          contrary, if the type being created does include
          ‘Py_TPFLAGS_HAVE_GC’ in its flags then it 'must' implement the
          GC protocol itself by at least implementing the *note
          tp_traverse: 781. handle.

 -- C Function: *note PyObject: 33a. *PyType_GetName (PyTypeObject
          *type)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.11.'  Return the type’s name.  Equivalent to
     getting the type’s *note __name__: 14fa. attribute.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyType_GetQualName (PyTypeObject
          *type)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.11.'  Return the type’s qualified name.  Equivalent
     to getting the type’s *note __qualname__: 20d5. attribute.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyType_GetFullyQualifiedName
          (PyTypeObject *type)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Return
     the type’s fully qualified name.  Equivalent to
     ‘f"{type.__module__}.{type.__qualname__}"’, or *note
     type.__qualname__: 20d5. if *note type.__module__: 377. is not a
     string or is equal to ‘"builtins"’.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyType_GetModuleName (PyTypeObject
          *type)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Return
     the type’s module name.  Equivalent to getting the *note
     type.__module__: 377. attribute.

     Added in version 3.13.

 -- C Function: void *PyType_GetSlot (PyTypeObject *type, int slot)
     ' Part of the *note Stable ABI: 556. since version 3.4.'  Return
     the function pointer stored in the given slot.  If the result is
     ‘NULL’, this indicates that either the slot is ‘NULL’, or that the
     function was called with invalid parameters.  Callers will
     typically cast the result pointer into the appropriate function
     type.

     See *note PyType_Slot.slot: 4f95. for possible values of the 'slot'
     argument.

     Added in version 3.4.

     Changed in version 3.10: *note PyType_GetSlot(): 8a3. can now
     accept all types.  Previously, it was limited to *note heap types:
     96f.

 -- C Function: *note PyObject: 33a. *PyType_GetModule (PyTypeObject
          *type)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.10.'  Return the module object associated with
     the given type when the type was created using *note
     PyType_FromModuleAndSpec(): 554.

     The returned reference is *note borrowed: 33f. from 'type', and
     will be valid as long as you hold a reference to 'type'.  Do not
     release it with *note Py_DECREF(): 572. or similar.

     If no module is associated with the given type, sets *note
     TypeError: 2c3. and returns ‘NULL’.

     This function is usually used to get the module in which a method
     is defined.  Note that in such a method,
     ‘PyType_GetModule(Py_TYPE(self))’ may not return the intended
     result.  ‘Py_TYPE(self)’ may be a 'subclass' of the intended class,
     and subclasses are not necessarily defined in the same module as
     their superclass.  See *note PyCMethod: 767. to get the class that
     defines the method.  See *note PyType_GetModuleByDef(): 397. for
     cases when ‘PyCMethod’ cannot be used.

     Added in version 3.9.

 -- C Function: void *PyType_GetModuleState (PyTypeObject *type)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Return
     the state of the module object associated with the given type.
     This is a shortcut for calling *note PyModule_GetState(): 98a. on
     the result of *note PyType_GetModule(): 978.

     If no module is associated with the given type, sets *note
     TypeError: 2c3. and returns ‘NULL’.

     If the 'type' has an associated module but its state is ‘NULL’,
     returns ‘NULL’ without setting an exception.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyType_GetModuleByDef
          (PyTypeObject *type, struct PyModuleDef *def)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.13.'  Find the first superclass whose module
     was created from the given *note PyModuleDef: 987. 'def', and
     return that module.

     If no module is found, raises a *note TypeError: 2c3. and returns
     ‘NULL’.

     This function is intended to be used together with *note
     PyModule_GetState(): 98a. to get module state from slot methods
     (such as *note tp_init: 584. or *note nb_add: 4f96.) and other
     places where a method’s defining class cannot be passed using the
     *note PyCMethod: 767. calling convention.

     The returned reference is *note borrowed: 33f. from 'type', and
     will be valid as long as you hold a reference to 'type'.  Do not
     release it with *note Py_DECREF(): 572. or similar.

     Added in version 3.11.

 -- C Function: int PyUnstable_Type_AssignVersionTag (PyTypeObject
          *type)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Attempt to assign a version tag to the given type.

     Returns 1 if the type already had a valid version tag or a new one
     was assigned, or 0 if a new tag could not be assigned.

     Added in version 3.12.

 -- C Function: int PyType_SUPPORTS_WEAKREFS (PyTypeObject *type)

     Return true if instances of 'type' support creating weak
     references, false otherwise.  This function always succeeds.
     'type' must not be ‘NULL’.

     See also
     ........

        * *note Weak Reference Objects: 4f99.

        * *note weakref: 114.

* Menu:

* Creating Heap-Allocated Types::


File: python.info,  Node: Creating Heap-Allocated Types,  Up: Type Objects<2>

7.8.1.2 Creating Heap-Allocated Types
.....................................

The following functions and structs are used to create *note heap types:
96f.

 -- C Function: *note PyObject: 33a. *PyType_FromMetaclass (PyTypeObject
          *metaclass, PyObject *module, PyType_Spec *spec, PyObject
          *bases)
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Create
     and return a *note heap type: 96f. from the 'spec' (see *note
     Py_TPFLAGS_HEAPTYPE: 8b7.).

     The metaclass 'metaclass' is used to construct the resulting type
     object.  When 'metaclass' is ‘NULL’, the metaclass is derived from
     'bases' (or 'Py_tp_base[s]' slots if 'bases' is ‘NULL’, see below).

     Metaclasses that override *note tp_new: 582. are not supported,
     except if ‘tp_new’ is ‘NULL’.  (For backwards compatibility, other
     ‘PyType_From*’ functions allow such metaclasses.  They ignore
     ‘tp_new’, which may result in incomplete initialization.  This is
     deprecated and in Python 3.14+ such metaclasses will not be
     supported.)

     The 'bases' argument can be used to specify base classes; it can
     either be only one class or a tuple of classes.  If 'bases' is
     ‘NULL’, the 'Py_tp_bases' slot is used instead.  If that also is
     ‘NULL’, the 'Py_tp_base' slot is used instead.  If that also is
     ‘NULL’, the new type derives from *note object: a9b.

     The 'module' argument can be used to record the module in which the
     new class is defined.  It must be a module object or ‘NULL’.  If
     not ‘NULL’, the module is associated with the new type and can
     later be retrieved with *note PyType_GetModule(): 978.  The
     associated module is not inherited by subclasses; it must be
     specified for each class individually.

     This function calls *note PyType_Ready(): 77f. on the new type.

     Note that this function does 'not' fully match the behavior of
     calling *note type(): d71. or using the *note class: 131f.
     statement.  With user-provided base types or metaclasses, prefer
     *note calling: 4f44. ‘type’ (or the metaclass) over ‘PyType_From*’
     functions.  Specifically:

        * *note __new__(): 583. is not called on the new class (and it
          must be set to ‘type.__new__’).

        * *note __init__(): 6b3. is not called on the new class.

        * *note __init_subclass__(): 634. is not called on any bases.

        * *note __set_name__(): c6f. is not called on new descriptors.

     Added in version 3.12.

 -- C Function: *note PyObject: 33a. *PyType_FromModuleAndSpec (PyObject
          *module, PyType_Spec *spec, PyObject *bases)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.10.'  Equivalent to ‘PyType_FromMetaclass(NULL,
     module, spec, bases)’.

     Added in version 3.9.

     Changed in version 3.10: The function now accepts a single class as
     the 'bases' argument and ‘NULL’ as the ‘tp_doc’ slot.

     Changed in version 3.12: The function now finds and uses a
     metaclass corresponding to the provided base classes.  Previously,
     only *note type: d71. instances were returned.

     The *note tp_new: 582. of the metaclass is 'ignored'.  which may
     result in incomplete initialization.  Creating classes whose
     metaclass overrides ‘tp_new’ is deprecated and in Python 3.14+ it
     will be no longer allowed.

 -- C Function: *note PyObject: 33a. *PyType_FromSpecWithBases
          (PyType_Spec *spec, PyObject *bases)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.3.'  Equivalent to ‘PyType_FromMetaclass(NULL,
     NULL, spec, bases)’.

     Added in version 3.3.

     Changed in version 3.12: The function now finds and uses a
     metaclass corresponding to the provided base classes.  Previously,
     only *note type: d71. instances were returned.

     The *note tp_new: 582. of the metaclass is 'ignored'.  which may
     result in incomplete initialization.  Creating classes whose
     metaclass overrides ‘tp_new’ is deprecated and in Python 3.14+ it
     will be no longer allowed.

 -- C Function: *note PyObject: 33a. *PyType_FromSpec (PyType_Spec
          *spec)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Equivalent to ‘PyType_FromMetaclass(NULL, NULL, spec,
     NULL)’.

     Changed in version 3.12: The function now finds and uses a
     metaclass corresponding to the base classes provided in
     'Py_tp_base[s]' slots.  Previously, only *note type: d71. instances
     were returned.

     The *note tp_new: 582. of the metaclass is 'ignored'.  which may
     result in incomplete initialization.  Creating classes whose
     metaclass overrides ‘tp_new’ is deprecated and in Python 3.14+ it
     will be no longer allowed.

 -- C Type: type PyType_Spec
     ' Part of the *note Stable ABI: 556. (including all members).'
     Structure defining a type’s behavior.

      -- C Member: const char *name

          Name of the type, used to set *note PyTypeObject.tp_name:
          1a56.

      -- C Member: int basicsize

          If positive, specifies the size of the instance in bytes.  It
          is used to set *note PyTypeObject.tp_basicsize: 991.

          If zero, specifies that *note tp_basicsize: 991. should be
          inherited.

          If negative, the absolute value specifies how much space
          instances of the class need 'in addition' to the superclass.
          Use *note PyObject_GetTypeData(): 54c. to get a pointer to
          subclass-specific memory reserved this way.  For negative
          ‘basicsize’, Python will insert padding when needed to meet
          *note tp_basicsize: 991.’s alignment requirements.

          Changed in version 3.12: Previously, this field could not be
          negative.

      -- C Member: int itemsize

          Size of one element of a variable-size type, in bytes.  Used
          to set *note PyTypeObject.tp_itemsize: 2121.  See
          ‘tp_itemsize’ documentation for caveats.

          If zero, *note tp_itemsize: 2121. is inherited.  Extending
          arbitrary variable-sized classes is dangerous, since some
          types use a fixed offset for variable-sized memory, which can
          then overlap fixed-sized memory used by a subclass.  To help
          prevent mistakes, inheriting ‘itemsize’ is only possible in
          the following situations:

             - The base is not variable-sized (its *note tp_itemsize:
               2121.).

             - The requested *note PyType_Spec.basicsize: 54b. is
               positive, suggesting that the memory layout of the base
               class is known.

             - The requested *note PyType_Spec.basicsize: 54b. is zero,
               suggesting that the subclass does not access the
               instance’s memory directly.

             - With the *note Py_TPFLAGS_ITEMS_AT_END: 54e. flag.

      -- C Member: unsigned int flags

          Type flags, used to set *note PyTypeObject.tp_flags: 1a18.

          If the ‘Py_TPFLAGS_HEAPTYPE’ flag is not set, *note
          PyType_FromSpecWithBases(): 581. sets it automatically.

      -- C Member: *note PyType_Slot: 4da4. *slots

          Array of *note PyType_Slot: 4da4. structures.  Terminated by
          the special slot value ‘{0, NULL}’.

          Each slot ID should be specified at most once.

 -- C Type: type PyType_Slot
     ' Part of the *note Stable ABI: 556. (including all members).'
     Structure defining optional functionality of a type, containing a
     slot ID and a value pointer.

      -- C Member: int slot

          A slot ID.

          Slot IDs are named like the field names of the structures
          *note PyTypeObject: aba, *note PyNumberMethods: 146c, *note
          PySequenceMethods: 4bbe, *note PyMappingMethods: 4bbf. and
          *note PyAsyncMethods: 4f9f. with an added ‘Py_’ prefix.  For
          example, use:

             * ‘Py_tp_dealloc’ to set *note PyTypeObject.tp_dealloc:
               4b87.

             * ‘Py_nb_add’ to set *note PyNumberMethods.nb_add: 4f96.

             * ‘Py_sq_length’ to set *note PySequenceMethods.sq_length:
               4fa0.

          The following “offset” fields cannot be set using *note
          PyType_Slot: 4da4.:

             * *note tp_weaklistoffset: 992. (use *note
               Py_TPFLAGS_MANAGED_WEAKREF: 55d. instead if possible)

             * *note tp_dictoffset: 4fa1. (use *note
               Py_TPFLAGS_MANAGED_DICT: 36e. instead if possible)

             * *note tp_vectorcall_offset: 4f46. (use
               ‘"__vectorcalloffset__"’ in *note PyMemberDef: 4fa2.)

          If it is not possible to switch to a ‘MANAGED’ flag (for
          example, for vectorcall or to support Python older than 3.12),
          specify the offset in *note Py_tp_members: 4b9c.  See *note
          PyMemberDef documentation: 4fa2. for details.

          The following fields cannot be set at all when creating a heap
          type:

             * *note tp_vectorcall: 4fa3. (use *note tp_new: 582. and/or
               *note tp_init: 584.)

             * Internal fields: *note tp_dict: 182b, *note tp_mro: 4fa4,
               *note tp_cache: 4fa5, *note tp_subclasses: 575, and *note
               tp_weaklist: 4fa6.

          Setting *note Py_tp_bases: 4e42. or *note Py_tp_base: 4e41.
          may be problematic on some platforms.  To avoid issues, use
          the 'bases' argument of *note PyType_FromSpecWithBases(): 581.
          instead.

          Changed in version 3.9: Slots in *note PyBufferProcs: 4fa7.
          may be set in the unlimited API.

          Changed in version 3.11: *note bf_getbuffer: 765. and *note
          bf_releasebuffer: 766. are now available under the *note
          limited API: 399.

      -- C Member: void *pfunc

          The desired value of the slot.  In most cases, this is a
          pointer to a function.

          Slots other than ‘Py_tp_doc’ may not be ‘NULL’.


File: python.info,  Node: The None Object,  Prev: Type Objects<2>,  Up: Fundamental Objects

7.8.1.3 The ‘None’ Object
.........................

Note that the *note PyTypeObject: aba. for ‘None’ is not directly
exposed in the Python/C API. Since ‘None’ is a singleton, testing for
object identity (using ‘==’ in C) is sufficient.  There is no
‘PyNone_Check()’ function for the same reason.

 -- C Variable: *note PyObject: 33a. *Py_None

     The Python ‘None’ object, denoting lack of value.  This object has
     no methods and is *note immortal: 45dd.

     Changed in version 3.12: *note Py_None: 4b69. is *note immortal:
     45dd.

 -- C Macro: Py_RETURN_NONE

     Return *note Py_None: 4b69. from a function.


File: python.info,  Node: Numeric Objects,  Next: Sequence Objects,  Prev: Fundamental Objects,  Up: Concrete Objects Layer

7.8.2 Numeric Objects
---------------------

* Menu:

* Integer Objects::
* Boolean Objects::
* Floating-Point Objects::
* Complex Number Objects::


File: python.info,  Node: Integer Objects,  Next: Boolean Objects,  Up: Numeric Objects

7.8.2.1 Integer Objects
.......................

All integers are implemented as “long” integer objects of arbitrary
size.

On error, most ‘PyLong_As*’ APIs return ‘(return type)-1’ which cannot
be distinguished from a number.  Use *note PyErr_Occurred(): 1a55. to
disambiguate.

 -- C Type: type PyLongObject
     ' Part of the *note Limited API: 556. (as an opaque struct).'  This
     subtype of *note PyObject: 33a. represents a Python integer object.

 -- C Variable: *note PyTypeObject: aba. PyLong_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python integer type.  This is the
     same object as *note int: 257. in the Python layer.

 -- C Function: int PyLong_Check (PyObject *p)

     Return true if its argument is a *note PyLongObject: 58b. or a
     subtype of ‘PyLongObject’.  This function always succeeds.

 -- C Function: int PyLong_CheckExact (PyObject *p)

     Return true if its argument is a *note PyLongObject: 58b, but not a
     subtype of ‘PyLongObject’.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyLong_FromLong (long v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from 'v', or
     ‘NULL’ on failure.

     'CPython implementation detail:' CPython keeps an array of integer
     objects for all integers between ‘-5’ and ‘256’.  When you create
     an int in that range you actually just get back a reference to the
     existing object.

 -- C Function: *note PyObject: 33a. *PyLong_FromUnsignedLong (unsigned
          long v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from a C
     unsigned long, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromSsize_t (Py_ssize_t v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from a C *note
     Py_ssize_t: a6e, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromSize_t (size_t v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from a C
     ‘size_t’, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromLongLong (long long v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from a C long
     long, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromUnsignedLongLong
          (unsigned long long v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from a C
     unsigned long long, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromDouble (double v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. object from the
     integer part of 'v', or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyLong_FromString (const char
          *str, char **pend, int base)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyLongObject: 58b. based on the string
     value in 'str', which is interpreted according to the radix in
     'base', or ‘NULL’ on failure.  If 'pend' is non-‘NULL’, '*pend'
     will point to the end of 'str' on success or to the first character
     that could not be processed on error.  If 'base' is ‘0’, 'str' is
     interpreted using the *note Integer literals: 2074. definition; in
     this case, leading zeros in a non-zero decimal number raises a
     *note ValueError: 202.  If 'base' is not ‘0’, it must be between
     ‘2’ and ‘36’, inclusive.  Leading and trailing whitespace and
     single underscores after a base specifier and between digits are
     ignored.  If there are no digits or 'str' is not NULL-terminated
     following the digits and trailing whitespace, ‘ValueError’ will be
     raised.

     See also
     ........

     Python methods *note int.to_bytes(): 19d8. and *note
     int.from_bytes(): 198d. to convert a *note PyLongObject: 58b.
     to/from an array of bytes in base ‘256’.  You can call those from C
     using *note PyObject_CallMethod(): 3a2.

 -- C Function: *note PyObject: 33a. *PyLong_FromUnicodeObject (PyObject
          *u, int base)
     'Return value: New reference.'  Convert a sequence of Unicode
     digits in the string 'u' to a Python integer value.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyLong_FromVoidPtr (void *p)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Python integer from the pointer 'p'.  The pointer
     value can be retrieved from the resulting value using *note
     PyLong_AsVoidPtr(): 4d0f.

 -- C Function: *note PyObject: 33a. *PyLong_FromNativeBytes (const void
          *buffer, size_t n_bytes, int flags)

     Create a Python integer from the value contained in the first
     'n_bytes' of 'buffer', interpreted as a two’s-complement signed
     number.

     'flags' are as for *note PyLong_AsNativeBytes(): 364.  Passing ‘-1’
     will select the native endian that CPython was compiled with and
     assume that the most-significant bit is a sign bit.  Passing
     ‘Py_ASNATIVEBYTES_UNSIGNED_BUFFER’ will produce the same result as
     calling *note PyLong_FromUnsignedNativeBytes(): 366.  Other flags
     are ignored.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyLong_FromUnsignedNativeBytes
          (const void *buffer, size_t n_bytes, int flags)

     Create a Python integer from the value contained in the first
     'n_bytes' of 'buffer', interpreted as an unsigned number.

     'flags' are as for *note PyLong_AsNativeBytes(): 364.  Passing ‘-1’
     will select the native endian that CPython was compiled with and
     assume that the most-significant bit is not a sign bit.  Flags
     other than endian are ignored.

     Added in version 3.13.

 -- C Macro: PyLong_FromPid (pid)

     Macro for creating a Python integer from a process identifier.

     This can be defined as an alias to *note PyLong_FromLong(): 1975.
     or *note PyLong_FromLongLong(): 1976, depending on the size of the
     system’s PID type.

     Added in version 3.2.

 -- C Function: long PyLong_AsLong (PyObject *obj)
     ' Part of the *note Stable ABI: 556.'

     Return a C long representation of 'obj'.  If 'obj' is not an
     instance of *note PyLongObject: 58b, first call its *note
     __index__(): 720. method (if present) to convert it to a
     ‘PyLongObject’.

     Raise *note OverflowError: 888. if the value of 'obj' is out of
     range for a long.

     Returns ‘-1’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

      -- C Function: long PyLong_AS_LONG (PyObject *obj)

          A *note soft deprecated: 209. alias.  Exactly equivalent to
          the preferred ‘PyLong_AsLong’.  In particular, it can fail
          with *note OverflowError: 888. or another exception.

          Deprecated since version 3.14: The function is soft
          deprecated.

 -- C Function: int PyLong_AsInt (PyObject *obj)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note PyLong_AsLong(): 363, but store the result in a C int
     instead of a C long.

     Added in version 3.13.

 -- C Function: long PyLong_AsLongAndOverflow (PyObject *obj, int
          *overflow)
     ' Part of the *note Stable ABI: 556.'  Return a C long
     representation of 'obj'.  If 'obj' is not an instance of *note
     PyLongObject: 58b, first call its *note __index__(): 720. method
     (if present) to convert it to a ‘PyLongObject’.

     If the value of 'obj' is greater than ‘LONG_MAX’ or less than
     ‘LONG_MIN’, set '*overflow' to ‘1’ or ‘-1’, respectively, and
     return ‘-1’; otherwise, set '*overflow' to ‘0’.  If any other
     exception occurs set '*overflow' to ‘0’ and return ‘-1’ as usual.

     Returns ‘-1’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

 -- C Function: long long PyLong_AsLongLong (PyObject *obj)
     ' Part of the *note Stable ABI: 556.'

     Return a C long long representation of 'obj'.  If 'obj' is not an
     instance of *note PyLongObject: 58b, first call its *note
     __index__(): 720. method (if present) to convert it to a
     ‘PyLongObject’.

     Raise *note OverflowError: 888. if the value of 'obj' is out of
     range for a long long.

     Returns ‘-1’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

 -- C Function: long long PyLong_AsLongLongAndOverflow (PyObject *obj,
          int *overflow)
     ' Part of the *note Stable ABI: 556.'  Return a C long long
     representation of 'obj'.  If 'obj' is not an instance of *note
     PyLongObject: 58b, first call its *note __index__(): 720. method
     (if present) to convert it to a ‘PyLongObject’.

     If the value of 'obj' is greater than ‘LLONG_MAX’ or less than
     ‘LLONG_MIN’, set '*overflow' to ‘1’ or ‘-1’, respectively, and
     return ‘-1’; otherwise, set '*overflow' to ‘0’.  If any other
     exception occurs set '*overflow' to ‘0’ and return ‘-1’ as usual.

     Returns ‘-1’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

     Added in version 3.2.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

 -- C Function: *note Py_ssize_t: a6e. PyLong_AsSsize_t (PyObject
          *pylong)
     ' Part of the *note Stable ABI: 556.'

     Return a C *note Py_ssize_t: a6e. representation of 'pylong'.
     'pylong' must be an instance of *note PyLongObject: 58b.

     Raise *note OverflowError: 888. if the value of 'pylong' is out of
     range for a *note Py_ssize_t: a6e.

     Returns ‘-1’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Function: unsigned long PyLong_AsUnsignedLong (PyObject *pylong)
     ' Part of the *note Stable ABI: 556.'

     Return a C unsigned long representation of 'pylong'.  'pylong' must
     be an instance of *note PyLongObject: 58b.

     Raise *note OverflowError: 888. if the value of 'pylong' is out of
     range for a unsigned long.

     Returns ‘(unsigned long)-1’ on error.  Use *note PyErr_Occurred():
     1a55. to disambiguate.

 -- C Function: size_t PyLong_AsSize_t (PyObject *pylong)
     ' Part of the *note Stable ABI: 556.'

     Return a C ‘size_t’ representation of 'pylong'.  'pylong' must be
     an instance of *note PyLongObject: 58b.

     Raise *note OverflowError: 888. if the value of 'pylong' is out of
     range for a ‘size_t’.

     Returns ‘(size_t)-1’ on error.  Use *note PyErr_Occurred(): 1a55.
     to disambiguate.

 -- C Function: unsigned long long PyLong_AsUnsignedLongLong (PyObject
          *pylong)
     ' Part of the *note Stable ABI: 556.'

     Return a C unsigned long long representation of 'pylong'.  'pylong'
     must be an instance of *note PyLongObject: 58b.

     Raise *note OverflowError: 888. if the value of 'pylong' is out of
     range for an unsigned long long.

     Returns ‘(unsigned long long)-1’ on error.  Use *note
     PyErr_Occurred(): 1a55. to disambiguate.

     Changed in version 3.1: A negative 'pylong' now raises *note
     OverflowError: 888, not *note TypeError: 2c3.

 -- C Function: unsigned long PyLong_AsUnsignedLongMask (PyObject *obj)
     ' Part of the *note Stable ABI: 556.'  Return a C unsigned long
     representation of 'obj'.  If 'obj' is not an instance of *note
     PyLongObject: 58b, first call its *note __index__(): 720. method
     (if present) to convert it to a ‘PyLongObject’.

     If the value of 'obj' is out of range for an unsigned long, return
     the reduction of that value modulo ‘ULONG_MAX + 1’.

     Returns ‘(unsigned long)-1’ on error.  Use *note PyErr_Occurred():
     1a55. to disambiguate.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

 -- C Function: unsigned long long PyLong_AsUnsignedLongLongMask
          (PyObject *obj)
     ' Part of the *note Stable ABI: 556.'  Return a C unsigned long
     long representation of 'obj'.  If 'obj' is not an instance of *note
     PyLongObject: 58b, first call its *note __index__(): 720. method
     (if present) to convert it to a ‘PyLongObject’.

     If the value of 'obj' is out of range for an unsigned long long,
     return the reduction of that value modulo ‘ULLONG_MAX + 1’.

     Returns ‘(unsigned long long)-1’ on error.  Use *note
     PyErr_Occurred(): 1a55. to disambiguate.

     Changed in version 3.8: Use *note __index__(): 720. if available.

     Changed in version 3.10: This function will no longer use *note
     __int__(): 71f.

 -- C Function: double PyLong_AsDouble (PyObject *pylong)
     ' Part of the *note Stable ABI: 556.'  Return a C double
     representation of 'pylong'.  'pylong' must be an instance of *note
     PyLongObject: 58b.

     Raise *note OverflowError: 888. if the value of 'pylong' is out of
     range for a double.

     Returns ‘-1.0’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Function: void *PyLong_AsVoidPtr (PyObject *pylong)
     ' Part of the *note Stable ABI: 556.'  Convert a Python integer
     'pylong' to a C void pointer.  If 'pylong' cannot be converted, an
     *note OverflowError: 888. will be raised.  This is only assured to
     produce a usable void pointer for values created with *note
     PyLong_FromVoidPtr(): 4d12.

     Returns ‘NULL’ on error.  Use *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Macro: PyLong_AsPid (pid)

     Macro for converting a Python integer into a process identifier.

     This can be defined as an alias to *note PyLong_AsLong(): 363,
     *note PyLong_FromLongLong(): 1976, or *note PyLong_AsInt(): 362,
     depending on the size of the system’s PID type.

     Added in version 3.2.

 -- C Function: *note Py_ssize_t: a6e. PyLong_AsNativeBytes (PyObject
          *pylong, void *buffer, Py_ssize_t n_bytes, int flags)

     Copy the Python integer value 'pylong' to a native 'buffer' of size
     'n_bytes'.  The 'flags' can be set to ‘-1’ to behave similarly to a
     C cast, or to values documented below to control the behavior.

     Returns ‘-1’ with an exception raised on error.  This may happen if
     'pylong' cannot be interpreted as an integer, or if 'pylong' was
     negative and the ‘Py_ASNATIVEBYTES_REJECT_NEGATIVE’ flag was set.

     Otherwise, returns the number of bytes required to store the value.
     If this is equal to or less than 'n_bytes', the entire value was
     copied.  All 'n_bytes' of the buffer are written: remaining bytes
     filled by copies of the sign bit.

     If the returned value is greater than 'n_bytes', the value was
     truncated: as many of the lowest bits of the value as could fit are
     written, and the higher bits are ignored.  This matches the typical
     behavior of a C-style downcast.

          Note: Overflow is not considered an error.  If the returned
          value is larger than 'n_bytes', most significant bits were
          discarded.

     ‘0’ will never be returned.

     Values are always copied as two’s-complement.

     Usage example:

          int32_t value;
          Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, &value, sizeof(value), -1);
          if (bytes < 0) {
              // Failed. A Python exception was set with the reason.
              return NULL;
          }
          else if (bytes <= (Py_ssize_t)sizeof(value)) {
              // Success!
          }
          else {
              // Overflow occurred, but 'value' contains the truncated
              // lowest bits of pylong.
          }

     Passing zero to 'n_bytes' will return the size of a buffer that
     would be large enough to hold the value.  This may be larger than
     technically necessary, but not unreasonably so.  If 'n_bytes=0',
     'buffer' may be ‘NULL’.

          Note: Passing 'n_bytes=0' to this function is not an accurate
          way to determine the bit length of the value.

     To get at the entire Python value of an unknown size, the function
     can be called twice: first to determine the buffer size, then to
     fill it:

          // Ask how much space we need.
          Py_ssize_t expected = PyLong_AsNativeBytes(pylong, NULL, 0, -1);
          if (expected < 0) {
              // Failed. A Python exception was set with the reason.
              return NULL;
          }
          assert(expected != 0);  // Impossible per the API definition.
          uint8_t *bignum = malloc(expected);
          if (!bignum) {
              PyErr_SetString(PyExc_MemoryError, "bignum malloc failed.");
              return NULL;
          }
          // Safely get the entire value.
          Py_ssize_t bytes = PyLong_AsNativeBytes(pylong, bignum, expected, -1);
          if (bytes < 0) {  // Exception has been set.
              free(bignum);
              return NULL;
          }
          else if (bytes > expected) {  // This should not be possible.
              PyErr_SetString(PyExc_RuntimeError,
                  "Unexpected bignum truncation after a size check.");
              free(bignum);
              return NULL;
          }
          // The expected success given the above pre-check.
          // ... use bignum ...
          free(bignum);

     'flags' is either ‘-1’ (‘Py_ASNATIVEBYTES_DEFAULTS’) to select
     defaults that behave most like a C cast, or a combination of the
     other flags in the table below.  Note that ‘-1’ cannot be combined
     with other flags.

     Currently, ‘-1’ corresponds to ‘Py_ASNATIVEBYTES_NATIVE_ENDIAN |
     Py_ASNATIVEBYTES_UNSIGNED_BUFFER’.

     Flag                                              Value
                                                       
     -------------------------------------------------------------
                                                       
      -- C Macro: Py_ASNATIVEBYTES_DEFAULTS            ‘-1’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_BIG_ENDIAN          ‘0’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_LITTLE_ENDIAN       ‘1’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_NATIVE_ENDIAN       ‘3’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_UNSIGNED_BUFFER     ‘4’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_REJECT_NEGATIVE     ‘8’
                                                       
                                                       
      -- C Macro: Py_ASNATIVEBYTES_ALLOW_INDEX         ‘16’
                                                       

     Specifying ‘Py_ASNATIVEBYTES_NATIVE_ENDIAN’ will override any other
     endian flags.  Passing ‘2’ is reserved.

     By default, sufficient buffer will be requested to include a sign
     bit.  For example, when converting 128 with 'n_bytes=1', the
     function will return 2 (or more) in order to store a zero sign bit.

     If ‘Py_ASNATIVEBYTES_UNSIGNED_BUFFER’ is specified, a zero sign bit
     will be omitted from size calculations.  This allows, for example,
     128 to fit in a single-byte buffer.  If the destination buffer is
     later treated as signed, a positive input value may become
     negative.  Note that the flag does not affect handling of negative
     values: for those, space for a sign bit is always requested.

     Specifying ‘Py_ASNATIVEBYTES_REJECT_NEGATIVE’ causes an exception
     to be set if 'pylong' is negative.  Without this flag, negative
     values will be copied provided there is enough space for at least
     one sign bit, regardless of whether
     ‘Py_ASNATIVEBYTES_UNSIGNED_BUFFER’ was specified.

     If ‘Py_ASNATIVEBYTES_ALLOW_INDEX’ is specified and a non-integer
     value is passed, its *note __index__(): 720. method will be called
     first.  This may result in Python code executing and other threads
     being allowed to run, which could cause changes to other objects or
     values in use.  When 'flags' is ‘-1’, this option is not set, and
     non-integer values will raise *note TypeError: 2c3.

          Note: With the default 'flags' (‘-1’, or 'UNSIGNED_BUFFER'
          without 'REJECT_NEGATIVE'), multiple Python integers can map
          to a single value without overflow.  For example, both ‘255’
          and ‘-1’ fit a single-byte buffer and set all its bits.  This
          matches typical C cast behavior.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyLong_GetInfo (void)
     ' Part of the *note Stable ABI: 556.'  On success, return a read
     only *note named tuple: 651, that holds information about Python’s
     internal representation of integers.  See *note sys.int_info: 12da.
     for description of individual fields.

     On failure, return ‘NULL’ with an exception set.

     Added in version 3.1.

 -- C Function: int PyUnstable_Long_IsCompact (const PyLongObject *op)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return 1 if 'op' is compact, 0 otherwise.

     This function makes it possible for performance-critical code to
     implement a “fast path” for small integers.  For compact values use
     *note PyUnstable_Long_CompactValue(): 58d.; for others fall back to
     a *note PyLong_As*: 4d0b. function or *note PyLong_AsNativeBytes():
     364.

     The speedup is expected to be negligible for most users.

     Exactly what values are considered compact is an implementation
     detail and is subject to change.

     Added in version 3.12.

 -- C Function: *note Py_ssize_t: a6e. PyUnstable_Long_CompactValue
          (const PyLongObject *op)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     If 'op' is compact, as determined by *note
     PyUnstable_Long_IsCompact(): 58c, return its value.

     Otherwise, the return value is undefined.

     Added in version 3.12.


File: python.info,  Node: Boolean Objects,  Next: Floating-Point Objects,  Prev: Integer Objects,  Up: Numeric Objects

7.8.2.2 Boolean Objects
.......................

Booleans in Python are implemented as a subclass of integers.  There are
only two booleans, *note Py_False: 4fc1. and *note Py_True: 4fc2.  As
such, the normal creation and deletion functions don’t apply to
booleans.  The following macros are available, however.

 -- C Variable: *note PyTypeObject: aba. PyBool_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python boolean type; it is the
     same object as *note bool: 46b. in the Python layer.

 -- C Function: int PyBool_Check (PyObject *o)

     Return true if 'o' is of type *note PyBool_Type: 4c39.  This
     function always succeeds.

 -- C Variable: *note PyObject: 33a. *Py_False

     The Python ‘False’ object.  This object has no methods and is *note
     immortal: 45dd.

     Changed in version 3.12: *note Py_False: 4fc1. is *note immortal:
     45dd.

 -- C Variable: *note PyObject: 33a. *Py_True

     The Python ‘True’ object.  This object has no methods and is *note
     immortal: 45dd.

     Changed in version 3.12: *note Py_True: 4fc2. is *note immortal:
     45dd.

 -- C Macro: Py_RETURN_FALSE

     Return *note Py_False: 4fc1. from a function.

 -- C Macro: Py_RETURN_TRUE

     Return *note Py_True: 4fc2. from a function.

 -- C Function: *note PyObject: 33a. *PyBool_FromLong (long v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return *note Py_True: 4fc2. or *note Py_False: 4fc1,
     depending on the truth value of 'v'.


File: python.info,  Node: Floating-Point Objects,  Next: Complex Number Objects,  Prev: Boolean Objects,  Up: Numeric Objects

7.8.2.3 Floating-Point Objects
..............................

 -- C Type: type PyFloatObject

     This subtype of *note PyObject: 33a. represents a Python
     floating-point object.

 -- C Variable: *note PyTypeObject: aba. PyFloat_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python floating-point type.  This
     is the same object as *note float: 2f7. in the Python layer.

 -- C Function: int PyFloat_Check (PyObject *p)

     Return true if its argument is a *note PyFloatObject: 4fc8. or a
     subtype of ‘PyFloatObject’.  This function always succeeds.

 -- C Function: int PyFloat_CheckExact (PyObject *p)

     Return true if its argument is a *note PyFloatObject: 4fc8, but not
     a subtype of ‘PyFloatObject’.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyFloat_FromString (PyObject *str)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a *note PyFloatObject: 4fc8. object based on the
     string value in 'str', or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyFloat_FromDouble (double v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a *note PyFloatObject: 4fc8. object from 'v', or
     ‘NULL’ on failure.

 -- C Function: double PyFloat_AsDouble (PyObject *pyfloat)
     ' Part of the *note Stable ABI: 556.'  Return a C double
     representation of the contents of 'pyfloat'.  If 'pyfloat' is not a
     Python floating-point object but has a *note __float__(): 9d7.
     method, this method will first be called to convert 'pyfloat' into
     a float.  If ‘__float__()’ is not defined then it falls back to
     *note __index__(): 720.  This method returns ‘-1.0’ upon failure,
     so one should call *note PyErr_Occurred(): 1a55. to check for
     errors.

     Changed in version 3.8: Use *note __index__(): 720. if available.

 -- C Function: double PyFloat_AS_DOUBLE (PyObject *pyfloat)

     Return a C double representation of the contents of 'pyfloat', but
     without error checking.

 -- C Function: *note PyObject: 33a. *PyFloat_GetInfo (void)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a structseq instance which contains information about
     the precision, minimum and maximum values of a float.  It’s a thin
     wrapper around the header file ‘float.h’.

 -- C Function: double PyFloat_GetMax ()
     ' Part of the *note Stable ABI: 556.'  Return the maximum
     representable finite float 'DBL_MAX' as C double.

 -- C Function: double PyFloat_GetMin ()
     ' Part of the *note Stable ABI: 556.'  Return the minimum
     normalized positive float 'DBL_MIN' as C double.

 -- C Macro: Py_INFINITY

     This macro expands to a constant expression of type double, that
     represents the positive infinity.

     On most platforms, this is equivalent to the ‘INFINITY’ macro from
     the C11 standard ‘<math.h>’ header.

 -- C Macro: Py_NAN

     This macro expands to a constant expression of type double, that
     represents a quiet not-a-number (qNaN) value.

     On most platforms, this is equivalent to the ‘NAN’ macro from the
     C11 standard ‘<math.h>’ header.

 -- C Macro: Py_HUGE_VAL

     Equivalent to ‘INFINITY’.

     Deprecated since version 3.14: The macro is *note soft deprecated:
     209.

 -- C Macro: Py_MATH_E

     The definition (accurate for a double type) of the *note math.e:
     27d4. constant.

 -- C Macro: Py_MATH_El

     High precision (long double) definition of *note e: 27d4. constant.

 -- C Macro: Py_MATH_PI

     The definition (accurate for a double type) of the *note math.pi:
     27d3. constant.

 -- C Macro: Py_MATH_PIl

     High precision (long double) definition of *note pi: 27d3.
     constant.

 -- C Macro: Py_MATH_TAU

     The definition (accurate for a double type) of the *note math.tau:
     27d5. constant.

     Added in version 3.6.

 -- C Macro: Py_RETURN_NAN

     Return *note math.nan: 666. from a function.

     On most platforms, this is equivalent to ‘return
     PyFloat_FromDouble(NAN)’.

 -- C Macro: Py_RETURN_INF (sign)

     Return *note math.inf: ca7. or ‘-math.inf’ from a function,
     depending on the sign of 'sign'.

     On most platforms, this is equivalent to the following:

          return PyFloat_FromDouble(copysign(INFINITY, sign));

 -- C Macro: Py_IS_FINITE (X)

     Return ‘1’ if the given floating-point number 'X' is finite, that
     is, it is normal, subnormal or zero, but not infinite or NaN.
     Return ‘0’ otherwise.

     Deprecated since version 3.14: The macro is *note soft deprecated:
     209.  Use ‘isfinite’ instead.

 -- C Macro: Py_IS_INFINITY (X)

     Return ‘1’ if the given floating-point number 'X' is positive or
     negative infinity.  Return ‘0’ otherwise.

     Deprecated since version 3.14: The macro is *note soft deprecated:
     209.  Use ‘isinf’ instead.

 -- C Macro: Py_IS_NAN (X)

     Return ‘1’ if the given floating-point number 'X' is a not-a-number
     (NaN) value.  Return ‘0’ otherwise.

     Deprecated since version 3.14: The macro is *note soft deprecated:
     209.  Use ‘isnan’ instead.

* Menu:

* Pack and Unpack functions::


File: python.info,  Node: Pack and Unpack functions,  Up: Floating-Point Objects

7.8.2.4 Pack and Unpack functions
.................................

The pack and unpack functions provide an efficient platform-independent
way to store floating-point values as byte strings.  The Pack routines
produce a bytes string from a C double, and the Unpack routines produce
a C double from such a bytes string.  The suffix (2, 4 or 8) specifies
the number of bytes in the bytes string.

On platforms that appear to use IEEE 754 formats these functions work by
copying bits.  On other platforms, the 2-byte format is identical to the
IEEE 754 binary16 half-precision format, the 4-byte format (32-bit) is
identical to the IEEE 754 binary32 single precision format, and the
8-byte format to the IEEE 754 binary64 double precision format, although
the packing of INFs and NaNs (if such things exist on the platform)
isn’t handled correctly, and attempting to unpack a bytes string
containing an IEEE INF or NaN will raise an exception.

On non-IEEE platforms with more precision, or larger dynamic range, than
IEEE 754 supports, not all values can be packed; on non-IEEE platforms
with less precision, or smaller dynamic range, not all values can be
unpacked.  What happens in such cases is partly accidental (alas).

Added in version 3.11.

* Menu:

* Pack functions::
* Unpack functions::


File: python.info,  Node: Pack functions,  Next: Unpack functions,  Up: Pack and Unpack functions

7.8.2.5 Pack functions
......................

The pack routines write 2, 4 or 8 bytes, starting at 'p'.  'le' is an
int argument, non-zero if you want the bytes string in little-endian
format (exponent last, at ‘p+1’, ‘p+3’, or ‘p+6’ ‘p+7’), zero if you
want big-endian format (exponent first, at 'p').  The ‘PY_BIG_ENDIAN’
constant can be used to use the native endian: it is equal to ‘1’ on big
endian processor, or ‘0’ on little endian processor.

Return value: ‘0’ if all is OK, ‘-1’ if error (and an exception is set,
most likely *note OverflowError: 888.).

There are two problems on non-IEEE platforms:

   * What this does is undefined if 'x' is a NaN or infinity.

   * ‘-0.0’ and ‘+0.0’ produce the same bytes string.

 -- C Function: int PyFloat_Pack2 (double x, char *p, int le)

     Pack a C double as the IEEE 754 binary16 half-precision format.

 -- C Function: int PyFloat_Pack4 (double x, char *p, int le)

     Pack a C double as the IEEE 754 binary32 single precision format.

 -- C Function: int PyFloat_Pack8 (double x, char *p, int le)

     Pack a C double as the IEEE 754 binary64 double precision format.


File: python.info,  Node: Unpack functions,  Prev: Pack functions,  Up: Pack and Unpack functions

7.8.2.6 Unpack functions
........................

The unpack routines read 2, 4 or 8 bytes, starting at 'p'.  'le' is an
int argument, non-zero if the bytes string is in little-endian format
(exponent last, at ‘p+1’, ‘p+3’ or ‘p+6’ and ‘p+7’), zero if big-endian
(exponent first, at 'p').  The ‘PY_BIG_ENDIAN’ constant can be used to
use the native endian: it is equal to ‘1’ on big endian processor, or
‘0’ on little endian processor.

Return value: The unpacked double.  On error, this is ‘-1.0’ and *note
PyErr_Occurred(): 1a55. is true (and an exception is set, most likely
*note OverflowError: 888.).

Note that on a non-IEEE platform this will refuse to unpack a bytes
string that represents a NaN or infinity.

 -- C Function: double PyFloat_Unpack2 (const char *p, int le)

     Unpack the IEEE 754 binary16 half-precision format as a C double.

 -- C Function: double PyFloat_Unpack4 (const char *p, int le)

     Unpack the IEEE 754 binary32 single precision format as a C double.

 -- C Function: double PyFloat_Unpack8 (const char *p, int le)

     Unpack the IEEE 754 binary64 double precision format as a C double.


File: python.info,  Node: Complex Number Objects,  Prev: Floating-Point Objects,  Up: Numeric Objects

7.8.2.7 Complex Number Objects
..............................

Python’s complex number objects are implemented as two distinct types
when viewed from the C API: one is the Python object exposed to Python
programs, and the other is a C structure which represents the actual
complex number value.  The API provides functions for working with both.

* Menu:

* Complex Numbers as C Structures::
* Complex Numbers as Python Objects::


File: python.info,  Node: Complex Numbers as C Structures,  Next: Complex Numbers as Python Objects,  Up: Complex Number Objects

7.8.2.8 Complex Numbers as C Structures
.......................................

Note that the functions which accept these structures as parameters and
return them as results do so 'by value' rather than dereferencing them
through pointers.  This is consistent throughout the API.

 -- C Type: type Py_complex

     The C structure which corresponds to the value portion of a Python
     complex number object.  Most of the functions for dealing with
     complex number objects use structures of this type as input or
     output values, as appropriate.

      -- C Member: double real
      -- C Member: double imag

     The structure is defined as:

          typedef struct {
              double real;
              double imag;
          } Py_complex;

 -- C Function: *note Py_complex: 4eee. _Py_c_sum (Py_complex left,
          Py_complex right)

     Return the sum of two complex numbers, using the C *note
     Py_complex: 4eee. representation.

 -- C Function: *note Py_complex: 4eee. _Py_c_diff (Py_complex left,
          Py_complex right)

     Return the difference between two complex numbers, using the C
     *note Py_complex: 4eee. representation.

 -- C Function: *note Py_complex: 4eee. _Py_c_neg (Py_complex num)

     Return the negation of the complex number 'num', using the C *note
     Py_complex: 4eee. representation.

 -- C Function: *note Py_complex: 4eee. _Py_c_prod (Py_complex left,
          Py_complex right)

     Return the product of two complex numbers, using the C *note
     Py_complex: 4eee. representation.

 -- C Function: *note Py_complex: 4eee. _Py_c_quot (Py_complex dividend,
          Py_complex divisor)

     Return the quotient of two complex numbers, using the C *note
     Py_complex: 4eee. representation.

     If 'divisor' is null, this method returns zero and sets ‘errno’ to
     ‘EDOM’.

 -- C Function: *note Py_complex: 4eee. _Py_c_pow (Py_complex num,
          Py_complex exp)

     Return the exponentiation of 'num' by 'exp', using the C *note
     Py_complex: 4eee. representation.

     If 'num' is null and 'exp' is not a positive real number, this
     method returns zero and sets ‘errno’ to ‘EDOM’.


File: python.info,  Node: Complex Numbers as Python Objects,  Prev: Complex Numbers as C Structures,  Up: Complex Number Objects

7.8.2.9 Complex Numbers as Python Objects
.........................................

 -- C Type: type PyComplexObject

     This subtype of *note PyObject: 33a. represents a Python complex
     number object.

 -- C Variable: *note PyTypeObject: aba. PyComplex_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python complex number type.  It
     is the same object as *note complex: 2f8. in the Python layer.

 -- C Function: int PyComplex_Check (PyObject *p)

     Return true if its argument is a *note PyComplexObject: 4fe8. or a
     subtype of ‘PyComplexObject’.  This function always succeeds.

 -- C Function: int PyComplex_CheckExact (PyObject *p)

     Return true if its argument is a *note PyComplexObject: 4fe8, but
     not a subtype of ‘PyComplexObject’.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyComplex_FromCComplex (Py_complex
          v)
     'Return value: New reference.'  Create a new Python complex number
     object from a C *note Py_complex: 4eee. value.  Return ‘NULL’ with
     an exception set on error.

 -- C Function: *note PyObject: 33a. *PyComplex_FromDoubles (double
          real, double imag)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note PyComplexObject: 4fe8. object from 'real'
     and 'imag'.  Return ‘NULL’ with an exception set on error.

 -- C Function: double PyComplex_RealAsDouble (PyObject *op)
     ' Part of the *note Stable ABI: 556.'  Return the real part of 'op'
     as a C double.

     If 'op' is not a Python complex number object but has a *note
     __complex__(): 5ea. method, this method will first be called to
     convert 'op' to a Python complex number object.  If ‘__complex__()’
     is not defined then it falls back to call *note PyFloat_AsDouble():
     a78. and returns its result.

     Upon failure, this method returns ‘-1.0’ with an exception set, so
     one should call *note PyErr_Occurred(): 1a55. to check for errors.

     Changed in version 3.13: Use *note __complex__(): 5ea. if
     available.

 -- C Function: double PyComplex_ImagAsDouble (PyObject *op)
     ' Part of the *note Stable ABI: 556.'  Return the imaginary part of
     'op' as a C double.

     If 'op' is not a Python complex number object but has a *note
     __complex__(): 5ea. method, this method will first be called to
     convert 'op' to a Python complex number object.  If ‘__complex__()’
     is not defined then it falls back to call *note PyFloat_AsDouble():
     a78. and returns ‘0.0’ on success.

     Upon failure, this method returns ‘-1.0’ with an exception set, so
     one should call *note PyErr_Occurred(): 1a55. to check for errors.

     Changed in version 3.13: Use *note __complex__(): 5ea. if
     available.

 -- C Function: *note Py_complex: 4eee. PyComplex_AsCComplex (PyObject
          *op)

     Return the *note Py_complex: 4eee. value of the complex number
     'op'.

     If 'op' is not a Python complex number object but has a *note
     __complex__(): 5ea. method, this method will first be called to
     convert 'op' to a Python complex number object.  If ‘__complex__()’
     is not defined then it falls back to *note __float__(): 9d7.  If
     ‘__float__()’ is not defined then it falls back to *note
     __index__(): 720.

     Upon failure, this method returns *note Py_complex: 4eee. with
     *note real: 4fe0. set to ‘-1.0’ and with an exception set, so one
     should call *note PyErr_Occurred(): 1a55. to check for errors.

     Changed in version 3.8: Use *note __index__(): 720. if available.


File: python.info,  Node: Sequence Objects,  Next: Container Objects,  Prev: Numeric Objects,  Up: Concrete Objects Layer

7.8.3 Sequence Objects
----------------------

Generic operations on sequence objects were discussed in the previous
chapter; this section deals with the specific kinds of sequence objects
that are intrinsic to the Python language.

* Menu:

* Bytes Objects: Bytes Objects<2>.
* Byte Array Objects::
* Unicode Objects and Codecs::
* Tuple Objects::
* Struct Sequence Objects::
* List Objects::


File: python.info,  Node: Bytes Objects<2>,  Next: Byte Array Objects,  Up: Sequence Objects

7.8.3.1 Bytes Objects
.....................

These functions raise *note TypeError: 2c3. when expecting a bytes
parameter and called with a non-bytes parameter.

 -- C Type: type PyBytesObject

     This subtype of *note PyObject: 33a. represents a Python bytes
     object.

 -- C Variable: *note PyTypeObject: aba. PyBytes_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python bytes type; it is the same
     object as *note bytes: 1c2. in the Python layer.

 -- C Function: int PyBytes_Check (PyObject *o)

     Return true if the object 'o' is a bytes object or an instance of a
     subtype of the bytes type.  This function always succeeds.

 -- C Function: int PyBytes_CheckExact (PyObject *o)

     Return true if the object 'o' is a bytes object, but not an
     instance of a subtype of the bytes type.  This function always
     succeeds.

 -- C Function: *note PyObject: 33a. *PyBytes_FromString (const char *v)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new bytes object with a copy of the string 'v' as
     value on success, and ‘NULL’ on failure.  The parameter 'v' must
     not be ‘NULL’; it will not be checked.

 -- C Function: *note PyObject: 33a. *PyBytes_FromStringAndSize (const
          char *v, Py_ssize_t len)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new bytes object with a copy of the string 'v' as
     value and length 'len' on success, and ‘NULL’ on failure.  If 'v'
     is ‘NULL’, the contents of the bytes object are uninitialized.

 -- C Function: *note PyObject: 33a. *PyBytes_FromFormat (const char
          *format, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Take a C ‘printf()’-style 'format' string and a variable
     number of arguments, calculate the size of the resulting Python
     bytes object and return a bytes object with the values formatted
     into it.  The variable arguments must be C types and must
     correspond exactly to the format characters in the 'format' string.
     The following format characters are allowed:

     Format Characters       Type                Comment
                                                 
     ---------------------------------------------------------------------------------
                                                 
     ‘%%’                    'n/a'               The literal % character.
                                                 
                                                 
     ‘%c’                    int                 A single byte, represented as a C
                                                 int.
                                                 
                                                 
     ‘%d’                    int                 Equivalent to ‘printf("%d")’.  (1)
                                                 
                                                 
     ‘%u’                    unsigned int        Equivalent to ‘printf("%u")’.  (2)
                                                 
                                                 
     ‘%ld’                   long                Equivalent to ‘printf("%ld")’.
                                                 (3)
                                                 
                                                 
     ‘%lu’                   unsigned long       Equivalent to ‘printf("%lu")’.
                                                 (4)
                                                 
                                                 
     ‘%zd’                   *note Py_ssize_t: a6e.Equivalent to ‘printf("%zd")’.
                                                 (5)
                                                 
                                                 
     ‘%zu’                   size_t              Equivalent to ‘printf("%zu")’.
                                                 (6)
                                                 
                                                 
     ‘%i’                    int                 Equivalent to ‘printf("%i")’.  (7)
                                                 
                                                 
     ‘%x’                    int                 Equivalent to ‘printf("%x")’.  (8)
                                                 
                                                 
     ‘%s’                    const char*         A null-terminated C character
                                                 array.
                                                 
                                                 
     ‘%p’                    const void*         The hex representation of a C
                                                 pointer.  Mostly equivalent to
                                                 ‘printf("%p")’ except that it is
                                                 guaranteed to start with the
                                                 literal ‘0x’ regardless of what
                                                 the platform’s ‘printf’ yields.
                                                 

     An unrecognized format character causes all the rest of the format
     string to be copied as-is to the result object, and any extra
     arguments discarded.

 -- C Function: *note PyObject: 33a. *PyBytes_FromFormatV (const char
          *format, va_list vargs)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Identical to *note PyBytes_FromFormat(): 1bba. except that
     it takes exactly two arguments.

 -- C Function: *note PyObject: 33a. *PyBytes_FromObject (PyObject *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the bytes representation of object 'o' that
     implements the buffer protocol.

 -- C Function: *note Py_ssize_t: a6e. PyBytes_Size (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Return the length of the
     bytes in bytes object 'o'.

 -- C Function: *note Py_ssize_t: a6e. PyBytes_GET_SIZE (PyObject *o)

     Similar to *note PyBytes_Size(): 4c49, but without error checking.

 -- C Function: char *PyBytes_AsString (PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Return a pointer to the
     contents of 'o'.  The pointer refers to the internal buffer of 'o',
     which consists of ‘len(o) + 1’ bytes.  The last byte in the buffer
     is always null, regardless of whether there are any other null
     bytes.  The data must not be modified in any way, unless the object
     was just created using ‘PyBytes_FromStringAndSize(NULL, size)’.  It
     must not be deallocated.  If 'o' is not a bytes object at all,
     *note PyBytes_AsString(): 88e. returns ‘NULL’ and raises *note
     TypeError: 2c3.

 -- C Function: char *PyBytes_AS_STRING (PyObject *string)

     Similar to *note PyBytes_AsString(): 88e, but without error
     checking.

 -- C Function: int PyBytes_AsStringAndSize (PyObject *obj, char
          **buffer, Py_ssize_t *length)
     ' Part of the *note Stable ABI: 556.'  Return the null-terminated
     contents of the object 'obj' through the output variables 'buffer'
     and 'length'.  Returns ‘0’ on success.

     If 'length' is ‘NULL’, the bytes object may not contain embedded
     null bytes; if it does, the function returns ‘-1’ and a *note
     ValueError: 202. is raised.

     The buffer refers to an internal buffer of 'obj', which includes an
     additional null byte at the end (not counted in 'length').  The
     data must not be modified in any way, unless the object was just
     created using ‘PyBytes_FromStringAndSize(NULL, size)’.  It must not
     be deallocated.  If 'obj' is not a bytes object at all, *note
     PyBytes_AsStringAndSize(): 4c41. returns ‘-1’ and raises *note
     TypeError: 2c3.

     Changed in version 3.5: Previously, *note TypeError: 2c3. was
     raised when embedded null bytes were encountered in the bytes
     object.

 -- C Function: void PyBytes_Concat (PyObject **bytes, PyObject
          *newpart)
     ' Part of the *note Stable ABI: 556.'  Create a new bytes object in
     '*bytes' containing the contents of 'newpart' appended to 'bytes';
     the caller will own the new reference.  The reference to the old
     value of 'bytes' will be stolen.  If the new object cannot be
     created, the old reference to 'bytes' will still be discarded and
     the value of '*bytes' will be set to ‘NULL’; the appropriate
     exception will be set.

 -- C Function: void PyBytes_ConcatAndDel (PyObject **bytes, PyObject
          *newpart)
     ' Part of the *note Stable ABI: 556.'  Create a new bytes object in
     '*bytes' containing the contents of 'newpart' appended to 'bytes'.
     This version releases the *note strong reference: 33e. to 'newpart'
     (i.e.  decrements its reference count).

 -- C Function: int _PyBytes_Resize (PyObject **bytes, Py_ssize_t
          newsize)

     Resize a bytes object.  'newsize' will be the new length of the
     bytes object.  You can think of it as creating a new bytes object
     and destroying the old one, only more efficiently.  Pass the
     address of an existing bytes object as an lvalue (it may be written
     into), and the new size desired.  On success, '*bytes' holds the
     resized bytes object and ‘0’ is returned; the address in '*bytes'
     may differ from its input value.  If the reallocation fails, the
     original bytes object at '*bytes' is deallocated, '*bytes' is set
     to ‘NULL’, *note MemoryError: 15ab. is set, and ‘-1’ is returned.

 -- C Function: *note PyObject: 33a. *PyBytes_Repr (PyObject *bytes, int
          smartquotes)
     ' Part of the *note Stable ABI: 556.'  Get the string
     representation of 'bytes'.  This function is currently used to
     implement ‘bytes.__repr__()’ in Python.

     This function does not do type checking; it is undefined behavior
     to pass 'bytes' as a non-bytes object or ‘NULL’.

     If 'smartquotes' is true, the representation will use a
     double-quoted string instead of single-quoted string when
     single-quotes are present in 'bytes'.  For example, the byte string
     ‘'Python'’ would be represented as ‘b"'Python'"’ when 'smartquotes'
     is true, or ‘b'\'Python\''’ when it is false.

     On success, this function returns a *note strong reference: 33e. to
     a *note str: 44f. object containing the representation.  On
     failure, this returns ‘NULL’ with an exception set.

 -- C Function: *note PyObject: 33a. *PyBytes_DecodeEscape (const char
          *s, Py_ssize_t len, const char *errors, Py_ssize_t unicode,
          const char *recode_encoding)
     ' Part of the *note Stable ABI: 556.'  Unescape a backslash-escaped
     string 's'.  's' must not be ‘NULL’.  'len' must be the size of
     's'.

     'errors' must be one of ‘"strict"’, ‘"replace"’, or ‘"ignore"’.  If
     'errors' is ‘NULL’, then ‘"strict"’ is used by default.

     On success, this function returns a *note strong reference: 33e. to
     a Python *note bytes: 1c2. object containing the unescaped string.
     On failure, this function returns ‘NULL’ with an exception set.

     Changed in version 3.9: 'unicode' and 'recode_encoding' are now
     unused.

   ---------- Footnotes ----------

   (1) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (2) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (3) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (4) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (5) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (6) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (7) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.

   (8) For integer specifiers (d, u, ld, lu, zd, zu, i, x): the
0-conversion flag has effect even when a precision is given.


File: python.info,  Node: Byte Array Objects,  Next: Unicode Objects and Codecs,  Prev: Bytes Objects<2>,  Up: Sequence Objects

7.8.3.2 Byte Array Objects
..........................

 -- C Type: type PyByteArrayObject

     This subtype of *note PyObject: 33a. represents a Python bytearray
     object.

 -- C Variable: *note PyTypeObject: aba. PyByteArray_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python bytearray type; it is the
     same object as *note bytearray: 2ea. in the Python layer.

* Menu:

* Type check macros::
* Direct API functions::
* Macros::


File: python.info,  Node: Type check macros,  Next: Direct API functions,  Up: Byte Array Objects

7.8.3.3 Type check macros
.........................

 -- C Function: int PyByteArray_Check (PyObject *o)

     Return true if the object 'o' is a bytearray object or an instance
     of a subtype of the bytearray type.  This function always succeeds.

 -- C Function: int PyByteArray_CheckExact (PyObject *o)

     Return true if the object 'o' is a bytearray object, but not an
     instance of a subtype of the bytearray type.  This function always
     succeeds.


File: python.info,  Node: Direct API functions,  Next: Macros,  Prev: Type check macros,  Up: Byte Array Objects

7.8.3.4 Direct API functions
............................

 -- C Function: *note PyObject: 33a. *PyByteArray_FromObject (PyObject
          *o)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new bytearray object from any object, 'o', that
     implements the *note buffer protocol: 2e8.

     On failure, return ‘NULL’ with an exception set.

 -- C Function: *note PyObject: 33a. *PyByteArray_FromStringAndSize
          (const char *string, Py_ssize_t len)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a new bytearray object from 'string' and its length,
     'len'.

     On failure, return ‘NULL’ with an exception set.

 -- C Function: *note PyObject: 33a. *PyByteArray_Concat (PyObject *a,
          PyObject *b)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Concat bytearrays 'a' and 'b' and return a new bytearray
     with the result.

     On failure, return ‘NULL’ with an exception set.

 -- C Function: *note Py_ssize_t: a6e. PyByteArray_Size (PyObject
          *bytearray)
     ' Part of the *note Stable ABI: 556.'  Return the size of
     'bytearray' after checking for a ‘NULL’ pointer.

 -- C Function: char *PyByteArray_AsString (PyObject *bytearray)
     ' Part of the *note Stable ABI: 556.'  Return the contents of
     'bytearray' as a char array after checking for a ‘NULL’ pointer.
     The returned array always has an extra null byte appended.

 -- C Function: int PyByteArray_Resize (PyObject *bytearray, Py_ssize_t
          len)
     ' Part of the *note Stable ABI: 556.'  Resize the internal buffer
     of 'bytearray' to 'len'.


File: python.info,  Node: Macros,  Prev: Direct API functions,  Up: Byte Array Objects

7.8.3.5 Macros
..............

These macros trade safety for speed and they don’t check pointers.

 -- C Function: char *PyByteArray_AS_STRING (PyObject *bytearray)

     Similar to *note PyByteArray_AsString(): 4c3b, but without error
     checking.

 -- C Function: *note Py_ssize_t: a6e. PyByteArray_GET_SIZE (PyObject
          *bytearray)

     Similar to *note PyByteArray_Size(): 4c3e, but without error
     checking.


File: python.info,  Node: Unicode Objects and Codecs,  Next: Tuple Objects,  Prev: Byte Array Objects,  Up: Sequence Objects

7.8.3.6 Unicode Objects and Codecs
..................................

* Menu:

* Unicode Objects::
* Built-in Codecs::
* Methods and Slot Functions::


File: python.info,  Node: Unicode Objects,  Next: Built-in Codecs,  Up: Unicode Objects and Codecs

7.8.3.7 Unicode Objects
.......................

Since the implementation of PEP 393(1) in Python 3.3, Unicode objects
internally use a variety of representations, in order to allow handling
the complete range of Unicode characters while staying memory efficient.
There are special cases for strings where all code points are below 128,
256, or 65536; otherwise, code points must be below 1114112 (which is
the full Unicode range).

UTF-8 representation is created on demand and cached in the Unicode
object.

     Note: The *note Py_UNICODE: 3f0. representation has been removed
     since Python 3.12 with deprecated APIs.  See PEP 623(2) for more
     information.

* Menu:

* Unicode Type::
* Unicode Character Properties::
* Creating and accessing Unicode strings::
* Locale Encoding::
* File System Encoding::
* wchar_t Support::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0393/

   (2) https://peps.python.org/pep-0623/


File: python.info,  Node: Unicode Type,  Next: Unicode Character Properties,  Up: Unicode Objects

7.8.3.8 Unicode Type
....................

These are the basic Unicode object types used for the Unicode
implementation in Python:

 -- C Type: type Py_UCS4
 -- C Type: type Py_UCS2
 -- C Type: type Py_UCS1
     ' Part of the *note Stable ABI: 556.'  These types are typedefs for
     unsigned integer types wide enough to contain characters of 32
     bits, 16 bits and 8 bits, respectively.  When dealing with single
     Unicode characters, use *note Py_UCS4: 29b.

     Added in version 3.3.

 -- C Type: type Py_UNICODE

     This is a typedef of ‘wchar_t’, which is a 16-bit type or 32-bit
     type depending on the platform.

     Changed in version 3.3: In previous versions, this was a 16-bit
     type or a 32-bit type depending on whether you selected a “narrow”
     or “wide” Unicode version of Python at build time.

     Deprecated since version 3.13, will be removed in version 3.15.

 -- C Type: type PyASCIIObject
 -- C Type: type PyCompactUnicodeObject
 -- C Type: type PyUnicodeObject

     These subtypes of *note PyObject: 33a. represent a Python Unicode
     object.  In almost all cases, they shouldn’t be used directly,
     since all API functions that deal with Unicode objects take and
     return ‘PyObject’ pointers.

     Added in version 3.3.

 -- C Variable: *note PyTypeObject: aba. PyUnicode_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python Unicode type.  It is
     exposed to Python code as ‘str’.

 -- C Variable: *note PyTypeObject: aba. PyUnicodeIter_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python Unicode iterator type.  It
     is used to iterate over Unicode string objects.

The following APIs are C macros and static inlined functions for fast
checks and access to internal read-only data of Unicode objects:

 -- C Function: int PyUnicode_Check (PyObject *obj)

     Return true if the object 'obj' is a Unicode object or an instance
     of a Unicode subtype.  This function always succeeds.

 -- C Function: int PyUnicode_CheckExact (PyObject *obj)

     Return true if the object 'obj' is a Unicode object, but not an
     instance of a subtype.  This function always succeeds.

 -- C Function: int PyUnicode_READY (PyObject *unicode)

     Returns ‘0’.  This API is kept only for backward compatibility.

     Added in version 3.3.

     Deprecated since version 3.10: This API does nothing since Python
     3.12.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_GET_LENGTH (PyObject
          *unicode)

     Return the length of the Unicode string, in code points.  'unicode'
     has to be a Unicode object in the “canonical” representation (not
     checked).

     Added in version 3.3.

 -- C Function: *note Py_UCS1: 11b7. *PyUnicode_1BYTE_DATA (PyObject
          *unicode)
 -- C Function: *note Py_UCS2: 11b8. *PyUnicode_2BYTE_DATA (PyObject
          *unicode)
 -- C Function: *note Py_UCS4: 29b. *PyUnicode_4BYTE_DATA (PyObject
          *unicode)

     Return a pointer to the canonical representation cast to UCS1, UCS2
     or UCS4 integer types for direct character access.  No checks are
     performed if the canonical representation has the correct character
     size; use *note PyUnicode_KIND(): 11c1. to select the right
     function.

     Added in version 3.3.

 -- C Macro: PyUnicode_1BYTE_KIND
 -- C Macro: PyUnicode_2BYTE_KIND
 -- C Macro: PyUnicode_4BYTE_KIND

     Return values of the *note PyUnicode_KIND(): 11c1. macro.

     Added in version 3.3.

     Changed in version 3.12: ‘PyUnicode_WCHAR_KIND’ has been removed.

 -- C Function: int PyUnicode_KIND (PyObject *unicode)

     Return one of the PyUnicode kind constants (see above) that
     indicate how many bytes per character this Unicode object uses to
     store its data.  'unicode' has to be a Unicode object in the
     “canonical” representation (not checked).

     Added in version 3.3.

 -- C Function: void *PyUnicode_DATA (PyObject *unicode)

     Return a void pointer to the raw Unicode buffer.  'unicode' has to
     be a Unicode object in the “canonical” representation (not
     checked).

     Added in version 3.3.

 -- C Function: void PyUnicode_WRITE (int kind, void *data, Py_ssize_t
          index, Py_UCS4 value)

     Write into a canonical representation 'data' (as obtained with
     *note PyUnicode_DATA(): 11bd.).  This function performs no sanity
     checks, and is intended for usage in loops.  The caller should
     cache the 'kind' value and 'data' pointer as obtained from other
     calls.  'index' is the index in the string (starts at 0) and
     'value' is the new code point value which should be written to that
     location.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. PyUnicode_READ (int kind, void
          *data, Py_ssize_t index)

     Read a code point from a canonical representation 'data' (as
     obtained with *note PyUnicode_DATA(): 11bd.).  No checks or ready
     calls are performed.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. PyUnicode_READ_CHAR (PyObject
          *unicode, Py_ssize_t index)

     Read a character from a Unicode object 'unicode', which must be in
     the “canonical” representation.  This is less efficient than *note
     PyUnicode_READ(): 11c5. if you do multiple consecutive reads.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. PyUnicode_MAX_CHAR_VALUE (PyObject
          *unicode)

     Return the maximum code point that is suitable for creating another
     string based on 'unicode', which must be in the “canonical”
     representation.  This is always an approximation but more efficient
     than iterating over the string.

     Added in version 3.3.

 -- C Function: int PyUnicode_IsIdentifier (PyObject *unicode)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if the string is
     a valid identifier according to the language definition, section
     *note Identifiers and keywords: 2040.  Return ‘0’ otherwise.

     Changed in version 3.9: The function does not call *note
     Py_FatalError(): 98d. anymore if the string is not ready.


File: python.info,  Node: Unicode Character Properties,  Next: Creating and accessing Unicode strings,  Prev: Unicode Type,  Up: Unicode Objects

7.8.3.9 Unicode Character Properties
....................................

Unicode provides many different character properties.  The most often
needed ones are available through these macros which are mapped to C
functions depending on the Python configuration.

 -- C Function: int Py_UNICODE_ISSPACE (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a whitespace
     character.

 -- C Function: int Py_UNICODE_ISLOWER (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a lowercase
     character.

 -- C Function: int Py_UNICODE_ISUPPER (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is an uppercase
     character.

 -- C Function: int Py_UNICODE_ISTITLE (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a titlecase
     character.

 -- C Function: int Py_UNICODE_ISLINEBREAK (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a linebreak
     character.

 -- C Function: int Py_UNICODE_ISDECIMAL (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a decimal character.

 -- C Function: int Py_UNICODE_ISDIGIT (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a digit character.

 -- C Function: int Py_UNICODE_ISNUMERIC (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a numeric character.

 -- C Function: int Py_UNICODE_ISALPHA (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is an alphabetic
     character.

 -- C Function: int Py_UNICODE_ISALNUM (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is an alphanumeric
     character.

 -- C Function: int Py_UNICODE_ISPRINTABLE (Py_UCS4 ch)

     Return ‘1’ or ‘0’ depending on whether 'ch' is a printable
     character, in the sense of *note str.isprintable(): e08.

These APIs can be used for fast direct character conversions:

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_TOLOWER (Py_UCS4 ch)

     Return the character 'ch' converted to lower case.

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_TOUPPER (Py_UCS4 ch)

     Return the character 'ch' converted to upper case.

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_TOTITLE (Py_UCS4 ch)

     Return the character 'ch' converted to title case.

 -- C Function: int Py_UNICODE_TODECIMAL (Py_UCS4 ch)

     Return the character 'ch' converted to a decimal positive integer.
     Return ‘-1’ if this is not possible.  This function does not raise
     exceptions.

 -- C Function: int Py_UNICODE_TODIGIT (Py_UCS4 ch)

     Return the character 'ch' converted to a single digit integer.
     Return ‘-1’ if this is not possible.  This function does not raise
     exceptions.

 -- C Function: double Py_UNICODE_TONUMERIC (Py_UCS4 ch)

     Return the character 'ch' converted to a double.  Return ‘-1.0’ if
     this is not possible.  This function does not raise exceptions.

These APIs can be used to work with surrogates:

 -- C Function: int Py_UNICODE_IS_SURROGATE (Py_UCS4 ch)

     Check if 'ch' is a surrogate (‘0xD800 <= ch <= 0xDFFF’).

 -- C Function: int Py_UNICODE_IS_HIGH_SURROGATE (Py_UCS4 ch)

     Check if 'ch' is a high surrogate (‘0xD800 <= ch <= 0xDBFF’).

 -- C Function: int Py_UNICODE_IS_LOW_SURROGATE (Py_UCS4 ch)

     Check if 'ch' is a low surrogate (‘0xDC00 <= ch <= 0xDFFF’).

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_HIGH_SURROGATE (Py_UCS4
          ch)

     Return the high UTF-16 surrogate (‘0xD800’ to ‘0xDBFF’) for a
     Unicode code point in the range ‘[0x10000; 0x10FFFF]’.

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_LOW_SURROGATE (Py_UCS4
          ch)

     Return the low UTF-16 surrogate (‘0xDC00’ to ‘0xDFFF’) for a
     Unicode code point in the range ‘[0x10000; 0x10FFFF]’.

 -- C Function: *note Py_UCS4: 29b. Py_UNICODE_JOIN_SURROGATES (Py_UCS4
          high, Py_UCS4 low)

     Join two surrogate code points and return a single *note Py_UCS4:
     29b. value.  'high' and 'low' are respectively the leading and
     trailing surrogates in a surrogate pair.  'high' must be in the
     range ‘[0xD800; 0xDBFF]’ and 'low' must be in the range ‘[0xDC00;
     0xDFFF]’.


File: python.info,  Node: Creating and accessing Unicode strings,  Next: Locale Encoding,  Prev: Unicode Character Properties,  Up: Unicode Objects

7.8.3.10 Creating and accessing Unicode strings
...............................................

To create Unicode objects and access their basic sequence properties,
use these APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_New (Py_ssize_t size,
          Py_UCS4 maxchar)
     'Return value: New reference.'  Create a new Unicode object.
     'maxchar' should be the true maximum code point to be placed in the
     string.  As an approximation, it can be rounded up to the nearest
     value in the sequence 127, 255, 65535, 1114111.

     This is the recommended way to allocate a new Unicode object.
     Objects created using this function are not resizable.

     On error, set an exception and return ‘NULL’.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromKindAndData (int
          kind, const void *buffer, Py_ssize_t size)
     'Return value: New reference.'  Create a new Unicode object with
     the given 'kind' (possible values are *note PyUnicode_1BYTE_KIND:
     11c2. etc., as returned by *note PyUnicode_KIND(): 11c1.).  The
     'buffer' must point to an array of 'size' units of 1, 2 or 4 bytes
     per character, as given by the kind.

     If necessary, the input 'buffer' is copied and transformed into the
     canonical representation.  For example, if the 'buffer' is a UCS4
     string (*note PyUnicode_4BYTE_KIND: 11c4.) and it consists only of
     codepoints in the UCS1 range, it will be transformed into UCS1
     (*note PyUnicode_1BYTE_KIND: 11c2.).

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromStringAndSize (const
          char *str, Py_ssize_t size)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object from the char buffer 'str'.  The
     bytes will be interpreted as being UTF-8 encoded.  The buffer is
     copied into the new object.  The return value might be a shared
     object, i.e.  modification of the data is not allowed.

     This function raises *note SystemError: 578. when:

        * 'size' < 0,

        * 'str' is ‘NULL’ and 'size' > 0

     Changed in version 3.12: 'str' == ‘NULL’ with 'size' > 0 is not
     allowed anymore.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromString (const char
          *str)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object from a UTF-8 encoded null-terminated
     char buffer 'str'.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromFormat (const char
          *format, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Take a C ‘printf()’-style 'format' string and a variable
     number of arguments, calculate the size of the resulting Python
     Unicode string and return a string with the values formatted into
     it.  The variable arguments must be C types and must correspond
     exactly to the format characters in the 'format' ASCII-encoded
     string.

     A conversion specifier contains two or more characters and has the
     following components, which must occur in this order:

       1. The ‘'%'’ character, which marks the start of the specifier.

       2. Conversion flags (optional), which affect the result of some
          conversion types.

       3. Minimum field width (optional).  If specified as an ‘'*'’
          (asterisk), the actual width is given in the next argument,
          which must be of type int, and the object to convert comes
          after the minimum field width and optional precision.

       4. Precision (optional), given as a ‘'.'’ (dot) followed by the
          precision.  If specified as ‘'*'’ (an asterisk), the actual
          precision is given in the next argument, which must be of type
          int, and the value to convert comes after the precision.

       5. Length modifier (optional).

       6. Conversion type.

     The conversion flag characters are:

     Flag        Meaning
                 
     ------------------------------------------------------------------------------
                 
     ‘0’         The conversion will be zero padded for numeric values.
                 
                 
     ‘-’         The converted value is left adjusted (overrides the ‘0’ flag if
                 both are given).
                 

     The length modifiers for following integer conversions (‘d’, ‘i’,
     ‘o’, ‘u’, ‘x’, or ‘X’) specify the type of the argument (int by
     default):

     Modifier       Types
                    
     -------------------------------------------------------------------------
                    
     ‘l’            long or unsigned long
                    
                    
     ‘ll’           long long or unsigned long long
                    
                    
     ‘j’            ‘intmax_t’ or ‘uintmax_t’
                    
                    
     ‘z’            ‘size_t’ or ‘ssize_t’
                    
                    
     ‘t’            ‘ptrdiff_t’
                    

     The length modifier ‘l’ for following conversions ‘s’ or ‘V’
     specify that the type of the argument is const wchar_t*.

     The conversion specifiers are:

     Conversion Specifier                  Type                                  Comment
                                                                                 
     ------------------------------------------------------------------------------------------------------------------
                                                                                 
     ‘%’                                   'n/a'                                 The literal ‘%’ character.
                                                                                 
                                                                                 
     ‘d’, ‘i’                              Specified by the length modifier      The decimal representation of a
                                                                                 signed C integer.
                                                                                 
                                                                                 
     ‘u’                                   Specified by the length modifier      The decimal representation of an
                                                                                 unsigned C integer.
                                                                                 
                                                                                 
     ‘o’                                   Specified by the length modifier      The octal representation of an
                                                                                 unsigned C integer.
                                                                                 
                                                                                 
     ‘x’                                   Specified by the length modifier      The hexadecimal representation of
                                                                                 an unsigned C integer (lowercase).
                                                                                 
                                                                                 
     ‘X’                                   Specified by the length modifier      The hexadecimal representation of
                                                                                 an unsigned C integer (uppercase).
                                                                                 
                                                                                 
     ‘c’                                   int                                   A single character.
                                                                                 
                                                                                 
     ‘s’                                   const char* or const wchar_t*         A null-terminated C character
                                                                                 array.
                                                                                 
                                                                                 
     ‘p’                                   const void*                           The hex representation of a C
                                                                                 pointer.  Mostly equivalent to
                                                                                 ‘printf("%p")’ except that it is
                                                                                 guaranteed to start with the
                                                                                 literal ‘0x’ regardless of what the
                                                                                 platform’s ‘printf’ yields.
                                                                                 
                                                                                 
     ‘A’                                   *note PyObject: 33a.*                 The result of calling
                                                                                 *note ascii(): 1434.
                                                                                 
                                                                                 
     ‘U’                                   *note PyObject: 33a.*                 A Unicode object.
                                                                                 
                                                                                 
     ‘V’                                   *note PyObject: 33a.*, const char*    A Unicode object (which may be
                                           or const wchar_t*                     ‘NULL’) and a null-terminated C
                                                                                 character array as a second
                                                                                 parameter (which will be used, if
                                                                                 the first parameter is ‘NULL’).
                                                                                 
                                                                                 
     ‘S’                                   *note PyObject: 33a.*                 The result of calling
                                                                                 *note PyObject_Str(): 106d.
                                                                                 
                                                                                 
     ‘R’                                   *note PyObject: 33a.*                 The result of calling
                                                                                 *note PyObject_Repr(): 106c.
                                                                                 
                                                                                 
     ‘T’                                   *note PyObject: 33a.*                 Get the fully qualified name of an
                                                                                 object type; call
                                                                                 *note PyType_GetFullyQualifiedName(): 376.
                                                                                 
                                                                                 
     ‘#T’                                  *note PyObject: 33a.*                 Similar to ‘T’ format, but use a
                                                                                 colon (‘:’) as separator between
                                                                                 the module name and the qualified
                                                                                 name.
                                                                                 
                                                                                 
     ‘N’                                   *note PyTypeObject: aba.*             Get the fully qualified name of a
                                                                                 type; call
                                                                                 *note PyType_GetFullyQualifiedName(): 376.
                                                                                 
                                                                                 
     ‘#N’                                  *note PyTypeObject: aba.*             Similar to ‘N’ format, but use a
                                                                                 colon (‘:’) as separator between
                                                                                 the module name and the qualified
                                                                                 name.
                                                                                 

          Note: The width formatter unit is number of characters rather
          than bytes.  The precision formatter unit is number of bytes
          or ‘wchar_t’ items (if the length modifier ‘l’ is used) for
          ‘"%s"’ and ‘"%V"’ (if the ‘PyObject*’ argument is ‘NULL’), and
          a number of characters for ‘"%A"’, ‘"%U"’, ‘"%S"’, ‘"%R"’ and
          ‘"%V"’ (if the ‘PyObject*’ argument is not ‘NULL’).

          Note: Unlike to C ‘printf()’ the ‘0’ flag has effect even when
          a precision is given for integer conversions (‘d’, ‘i’, ‘u’,
          ‘o’, ‘x’, or ‘X’).

     Changed in version 3.2: Support for ‘"%lld"’ and ‘"%llu"’ added.

     Changed in version 3.3: Support for ‘"%li"’, ‘"%lli"’ and ‘"%zi"’
     added.

     Changed in version 3.4: Support width and precision formatter for
     ‘"%s"’, ‘"%A"’, ‘"%U"’, ‘"%V"’, ‘"%S"’, ‘"%R"’ added.

     Changed in version 3.12: Support for conversion specifiers ‘o’ and
     ‘X’.  Support for length modifiers ‘j’ and ‘t’.  Length modifiers
     are now applied to all integer conversions.  Length modifier ‘l’ is
     now applied to conversion specifiers ‘s’ and ‘V’.  Support for
     variable width and precision ‘*’.  Support for flag ‘-’.

     An unrecognized format character now sets a *note SystemError: 578.
     In previous versions it caused all the rest of the format string to
     be copied as-is to the result string, and any extra arguments
     discarded.

     Changed in version 3.13: Support for ‘%T’, ‘%#T’, ‘%N’ and ‘%#N’
     formats added.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromFormatV (const char
          *format, va_list vargs)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Identical to *note PyUnicode_FromFormat(): 38d. except that
     it takes exactly two arguments.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromObject (PyObject
          *obj)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Copy an instance of a Unicode subtype to a new true Unicode
     object if necessary.  If 'obj' is already a true Unicode object
     (not a subtype), return a new *note strong reference: 33e. to the
     object.

     Objects other than Unicode or its subtypes will cause a *note
     TypeError: 2c3.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromOrdinal (int
          ordinal)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode Object from the given Unicode code point
     'ordinal'.

     The ordinal must be in ‘range(0x110000)’.  A *note ValueError: 202.
     is raised in the case it is not.

 -- C Function: *note PyObject: 33a. *PyUnicode_FromEncodedObject
          (PyObject *obj, const char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Decode an encoded object 'obj' to a Unicode object.

     *note bytes: 1c2, *note bytearray: 2ea. and other *note bytes-like
     objects: d55. are decoded according to the given 'encoding' and
     using the error handling defined by 'errors'.  Both can be ‘NULL’
     to have the interface use the default values (see *note Built-in
     Codecs: 501f. for details).

     All other objects, including Unicode objects, cause a *note
     TypeError: 2c3. to be set.

     The API returns ‘NULL’ if there was an error.  The caller is
     responsible for decref’ing the returned objects.

 -- C Function: *note PyObject: 33a. *PyUnicode_BuildEncodingMap
          (PyObject *string)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a mapping suitable for decoding a custom single-byte
     encoding.  Given a Unicode string 'string' of up to 256 characters
     representing an encoding table, returns either a compact internal
     mapping object or a dictionary mapping character ordinals to byte
     values.  Raises a *note TypeError: 2c3. and return ‘NULL’ on
     invalid input.  ..  versionadded:: 3.2

 -- C Function: const char *PyUnicode_GetDefaultEncoding (void)
     ' Part of the *note Stable ABI: 556.'  Return the name of the
     default string encoding, ‘"utf-8"’.  See *note
     sys.getdefaultencoding(): 45db.

     The returned string does not need to be freed, and is valid until
     interpreter shutdown.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_GetLength (PyObject
          *unicode)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return
     the length of the Unicode object, in code points.

     On error, set an exception and return ‘-1’.

     Added in version 3.3.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_CopyCharacters
          (PyObject *to, Py_ssize_t to_start, PyObject *from, Py_ssize_t
          from_start, Py_ssize_t how_many)

     Copy characters from one Unicode object into another.  This
     function performs character conversion when necessary and falls
     back to ‘memcpy()’ if possible.  Returns ‘-1’ and sets an exception
     on error, otherwise returns the number of copied characters.

     Added in version 3.3.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_Fill (PyObject
          *unicode, Py_ssize_t start, Py_ssize_t length, Py_UCS4
          fill_char)

     Fill a string with a character: write 'fill_char' into
     ‘unicode[start:start+length]’.

     Fail if 'fill_char' is bigger than the string maximum character, or
     if the string has more than 1 reference.

     Return the number of written character, or return ‘-1’ and raise an
     exception on error.

     Added in version 3.3.

 -- C Function: int PyUnicode_WriteChar (PyObject *unicode, Py_ssize_t
          index, Py_UCS4 character)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Write a
     character to a string.  The string must have been created through
     *note PyUnicode_New(): 8b3.  Since Unicode strings are supposed to
     be immutable, the string must not be shared, or have been hashed
     yet.

     This function checks that 'unicode' is a Unicode object, that the
     index is not out of bounds, and that the object can be modified
     safely (i.e.  that it its reference count is one).

     Return ‘0’ on success, ‘-1’ on error with an exception set.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. PyUnicode_ReadChar (PyObject
          *unicode, Py_ssize_t index)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Read a
     character from a string.  This function checks that 'unicode' is a
     Unicode object and the index is not out of bounds, in contrast to
     *note PyUnicode_READ_CHAR(): 11c6, which performs no error
     checking.

     Return character on success, ‘-1’ on error with an exception set.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyUnicode_Substring (PyObject
          *unicode, Py_ssize_t start, Py_ssize_t end)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Return a substring of 'unicode', from
     character index 'start' (included) to character index 'end'
     (excluded).  Negative indices are not supported.  On error, set an
     exception and return ‘NULL’.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. *PyUnicode_AsUCS4 (PyObject
          *unicode, Py_UCS4 *buffer, Py_ssize_t buflen, int copy_null)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Copy the
     string 'unicode' into a UCS4 buffer, including a null character, if
     'copy_null' is set.  Returns ‘NULL’ and sets an exception on error
     (in particular, a *note SystemError: 578. if 'buflen' is smaller
     than the length of 'unicode').  'buffer' is returned on success.

     Added in version 3.3.

 -- C Function: *note Py_UCS4: 29b. *PyUnicode_AsUCS4Copy (PyObject
          *unicode)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Copy the
     string 'unicode' into a new UCS4 buffer that is allocated using
     *note PyMem_Malloc(): c87.  If this fails, ‘NULL’ is returned with
     a *note MemoryError: 15ab. set.  The returned buffer always has an
     extra null code point appended.

     Added in version 3.3.


File: python.info,  Node: Locale Encoding,  Next: File System Encoding,  Prev: Creating and accessing Unicode strings,  Up: Unicode Objects

7.8.3.11 Locale Encoding
........................

The current locale encoding can be used to decode text from the
operating system.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeLocaleAndSize
          (const char *str, Py_ssize_t length, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Decode a string from UTF-8 on Android and
     VxWorks, or from the current locale encoding on other platforms.
     The supported error handlers are ‘"strict"’ and ‘"surrogateescape"’
     ( PEP 383(1)).  The decoder uses ‘"strict"’ error handler if
     'errors' is ‘NULL’.  'str' must end with a null character but
     cannot contain embedded null characters.

     Use *note PyUnicode_DecodeFSDefaultAndSize(): 4dc7. to decode a
     string from the *note filesystem encoding and error handler: 53e.

     This function ignores the *note Python UTF-8 Mode: 659.

     See also
     ........

     The *note Py_DecodeLocale(): be6. function.

     Added in version 3.3.

     Changed in version 3.7: The function now also uses the current
     locale encoding for the ‘surrogateescape’ error handler, except on
     Android.  Previously, *note Py_DecodeLocale(): be6. was used for
     the ‘surrogateescape’, and the current locale encoding was used for
     ‘strict’.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeLocale (const char
          *str, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Similar to *note
     PyUnicode_DecodeLocaleAndSize(): be8, but compute the string length
     using ‘strlen()’.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyUnicode_EncodeLocale (PyObject
          *unicode, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Encode a Unicode object to UTF-8 on Android
     and VxWorks, or to the current locale encoding on other platforms.
     The supported error handlers are ‘"strict"’ and ‘"surrogateescape"’
     ( PEP 383(2)).  The encoder uses ‘"strict"’ error handler if
     'errors' is ‘NULL’.  Return a *note bytes: 1c2. object.  'unicode'
     cannot contain embedded null characters.

     Use *note PyUnicode_EncodeFSDefault(): 1be2. to encode a string to
     the *note filesystem encoding and error handler: 53e.

     This function ignores the *note Python UTF-8 Mode: 659.

     See also
     ........

     The *note Py_EncodeLocale(): be7. function.

     Added in version 3.3.

     Changed in version 3.7: The function now also uses the current
     locale encoding for the ‘surrogateescape’ error handler, except on
     Android.  Previously, *note Py_EncodeLocale(): be7. was used for
     the ‘surrogateescape’, and the current locale encoding was used for
     ‘strict’.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0383/

   (2) https://peps.python.org/pep-0383/


File: python.info,  Node: File System Encoding,  Next: wchar_t Support,  Prev: Locale Encoding,  Up: Unicode Objects

7.8.3.12 File System Encoding
.............................

Functions encoding to and decoding from the *note filesystem encoding
and error handler: 53e. ( PEP 383(1) and PEP 529(2)).

To encode file names to *note bytes: 1c2. during argument parsing, the
‘"O&"’ converter should be used, passing ‘PyUnicode_FSConverter()’ as
the conversion function:

 -- C Function: int PyUnicode_FSConverter (PyObject *obj, void *result)
     ' Part of the *note Stable ABI: 556.'  *note PyArg_Parse*
     converter: 8b0.: encode *note str: 44f. objects – obtained directly
     or through the *note os.PathLike: c72. interface – to *note bytes:
     1c2. using *note PyUnicode_EncodeFSDefault(): 1be2.; ‘bytes’
     objects are output as-is.  'result' must be an address of a C
     variable of type *note PyObject: 33a.* (or *note PyBytesObject:
     795.*).  On success, set the variable to a new *note strong
     reference: 33e. to a *note bytes object: 4ff0. which must be
     released when it is no longer used and return a non-zero value
     (*note Py_CLEANUP_SUPPORTED: 4ef1.).  Embedded null bytes are not
     allowed in the result.  On failure, return ‘0’ with an exception
     set.

     If 'obj' is ‘NULL’, the function releases a strong reference stored
     in the variable referred by 'result' and returns ‘1’.

     Added in version 3.1.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

To decode file names to *note str: 44f. during argument parsing, the
‘"O&"’ converter should be used, passing ‘PyUnicode_FSDecoder()’ as the
conversion function:

 -- C Function: int PyUnicode_FSDecoder (PyObject *obj, void *result)
     ' Part of the *note Stable ABI: 556.'  *note PyArg_Parse*
     converter: 8b0.: decode *note bytes: 1c2. objects – obtained either
     directly or indirectly through the *note os.PathLike: c72.
     interface – to *note str: 44f. using *note
     PyUnicode_DecodeFSDefaultAndSize(): 4dc7.; ‘str’ objects are output
     as-is.  'result' must be an address of a C variable of type *note
     PyObject: 33a.* (or *note PyUnicodeObject: 797.*).  On success, set
     the variable to a new *note strong reference: 33e. to a *note
     Unicode object: 5002. which must be released when it is no longer
     used and return a non-zero value (*note Py_CLEANUP_SUPPORTED:
     4ef1.).  Embedded null characters are not allowed in the result.
     On failure, return ‘0’ with an exception set.

     If 'obj' is ‘NULL’, release the strong reference to the object
     referred to by 'result' and return ‘1’.

     Added in version 3.2.

     Changed in version 3.6: Accepts a *note path-like object: 2a0.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeFSDefaultAndSize
          (const char *str, Py_ssize_t size)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Decode a string from the *note filesystem encoding and error
     handler: 53e.

     If you need to decode a string from the current locale encoding,
     use *note PyUnicode_DecodeLocaleAndSize(): be8.

     See also
     ........

     The *note Py_DecodeLocale(): be6. function.

     Changed in version 3.6: The *note filesystem error handler: 53e. is
     now used.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeFSDefault (const
          char *str)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Decode a null-terminated string from the *note filesystem
     encoding and error handler: 53e.

     If the string length is known, use *note
     PyUnicode_DecodeFSDefaultAndSize(): 4dc7.

     Changed in version 3.6: The *note filesystem error handler: 53e. is
     now used.

 -- C Function: *note PyObject: 33a. *PyUnicode_EncodeFSDefault
          (PyObject *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object to the *note filesystem encoding and
     error handler: 53e, and return *note bytes: 1c2.  Note that the
     resulting ‘bytes’ object can contain null bytes.

     If you need to encode a string to the current locale encoding, use
     *note PyUnicode_EncodeLocale(): be9.

     See also
     ........

     The *note Py_EncodeLocale(): be7. function.

     Added in version 3.2.

     Changed in version 3.6: The *note filesystem error handler: 53e. is
     now used.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0383/

   (2) https://peps.python.org/pep-0529/


File: python.info,  Node: wchar_t Support,  Prev: File System Encoding,  Up: Unicode Objects

7.8.3.13 wchar_t Support
........................

‘wchar_t’ support for platforms which support it:

 -- C Function: *note PyObject: 33a. *PyUnicode_FromWideChar (const
          wchar_t *wstr, Py_ssize_t size)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object from the ‘wchar_t’ buffer 'wstr' of
     the given 'size'.  Passing ‘-1’ as the 'size' indicates that the
     function must itself compute the length, using ‘wcslen()’.  Return
     ‘NULL’ on failure.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_AsWideChar (PyObject
          *unicode, wchar_t *wstr, Py_ssize_t size)
     ' Part of the *note Stable ABI: 556.'  Copy the Unicode object
     contents into the ‘wchar_t’ buffer 'wstr'.  At most 'size'
     ‘wchar_t’ characters are copied (excluding a possibly trailing null
     termination character).  Return the number of ‘wchar_t’ characters
     copied or ‘-1’ in case of an error.

     When 'wstr' is ‘NULL’, instead return the 'size' that would be
     required to store all of 'unicode' including a terminating null.

     Note that the resulting wchar_t* string may or may not be
     null-terminated.  It is the responsibility of the caller to make
     sure that the wchar_t* string is null-terminated in case this is
     required by the application.  Also, note that the wchar_t* string
     might contain null characters, which would cause the string to be
     truncated when used with most C functions.

 -- C Function: wchar_t *PyUnicode_AsWideCharString (PyObject *unicode,
          Py_ssize_t *size)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Convert
     the Unicode object to a wide character string.  The output string
     always ends with a null character.  If 'size' is not ‘NULL’, write
     the number of wide characters (excluding the trailing null
     termination character) into '*size'.  Note that the resulting
     ‘wchar_t’ string might contain null characters, which would cause
     the string to be truncated when used with most C functions.  If
     'size' is ‘NULL’ and the wchar_t* string contains null characters a
     *note ValueError: 202. is raised.

     Returns a buffer allocated by *note PyMem_New: 1574. (use *note
     PyMem_Free(): 1491. to free it) on success.  On error, returns
     ‘NULL’ and '*size' is undefined.  Raises a *note MemoryError: 15ab.
     if memory allocation is failed.

     Added in version 3.2.

     Changed in version 3.7: Raises a *note ValueError: 202. if 'size'
     is ‘NULL’ and the wchar_t* string contains null characters.


File: python.info,  Node: Built-in Codecs,  Next: Methods and Slot Functions,  Prev: Unicode Objects,  Up: Unicode Objects and Codecs

7.8.3.14 Built-in Codecs
........................

Python provides a set of built-in codecs which are written in C for
speed.  All of these codecs are directly usable via the following
functions.

Many of the following APIs take two arguments encoding and errors, and
they have the same semantics as the ones of the built-in *note str():
44f. string object constructor.

Setting encoding to ‘NULL’ causes the default encoding to be used which
is UTF-8.  The file system calls should use *note
PyUnicode_FSConverter(): d41. for encoding file names.  This uses the
*note filesystem encoding and error handler: 53e. internally.

Error handling is set by errors which may also be set to ‘NULL’ meaning
to use the default handling defined for the codec.  Default error
handling for all built-in codecs is “strict” (*note ValueError: 202. is
raised).

The codecs all use a similar interface.  Only deviations from the
following generic ones are documented for simplicity.

* Menu:

* Generic Codecs::
* UTF-8 Codecs::
* UTF-32 Codecs::
* UTF-16 Codecs::
* UTF-7 Codecs::
* Unicode-Escape Codecs::
* Raw-Unicode-Escape Codecs::
* Latin-1 Codecs::
* ASCII Codecs::
* Character Map Codecs::
* MBCS codecs for Windows::


File: python.info,  Node: Generic Codecs,  Next: UTF-8 Codecs,  Up: Built-in Codecs

7.8.3.15 Generic Codecs
.......................

These are the generic codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_Decode (const char *str,
          Py_ssize_t size, const char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     encoded string 'str'.  'encoding' and 'errors' have the same
     meaning as the parameters of the same name in the *note str(): 44f.
     built-in function.  The codec to be used is looked up using the
     Python codec registry.  Return ‘NULL’ if an exception was raised by
     the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsEncodedString
          (PyObject *unicode, const char *encoding, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object and return the result as Python
     bytes object.  'encoding' and 'errors' have the same meaning as the
     parameters of the same name in the Unicode *note encode(): 8de.
     method.  The codec to be used is looked up using the Python codec
     registry.  Return ‘NULL’ if an exception was raised by the codec.


File: python.info,  Node: UTF-8 Codecs,  Next: UTF-32 Codecs,  Prev: Generic Codecs,  Up: Built-in Codecs

7.8.3.16 UTF-8 Codecs
.....................

These are the UTF-8 codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF8 (const char
          *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     UTF-8 encoded string 'str'.  Return ‘NULL’ if an exception was
     raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF8Stateful
          (const char *str, Py_ssize_t size, const char *errors,
          Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  If 'consumed' is ‘NULL’, behave like *note
     PyUnicode_DecodeUTF8(): 4dd3.  If 'consumed' is not ‘NULL’,
     trailing incomplete UTF-8 byte sequences will not be treated as an
     error.  Those bytes will not be decoded and the number of bytes
     that have been decoded will be stored in 'consumed'.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsUTF8String (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using UTF-8 and return the result as
     Python bytes object.  Error handling is “strict”.  Return ‘NULL’ if
     an exception was raised by the codec.

     The function fails if the string contains surrogate code points
     (‘U+D800’ - ‘U+DFFF’).

 -- C Function: const char *PyUnicode_AsUTF8AndSize (PyObject *unicode,
          Py_ssize_t *size)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Return a
     pointer to the UTF-8 encoding of the Unicode object, and store the
     size of the encoded representation (in bytes) in 'size'.  The
     'size' argument can be ‘NULL’; in this case no size will be stored.
     The returned buffer always has an extra null byte appended (not
     included in 'size'), regardless of whether there are any other null
     code points.

     On error, set an exception, set 'size' to ‘-1’ (if it’s not NULL)
     and return ‘NULL’.

     The function fails if the string contains surrogate code points
     (‘U+D800’ - ‘U+DFFF’).

     This caches the UTF-8 representation of the string in the Unicode
     object, and subsequent calls will return a pointer to the same
     buffer.  The caller is not responsible for deallocating the buffer.
     The buffer is deallocated and pointers to it become invalid when
     the Unicode object is garbage collected.

     Added in version 3.3.

     Changed in version 3.7: The return type is now ‘const char *’
     rather of ‘char *’.

     Changed in version 3.10: This function is a part of the *note
     limited API: 399.

 -- C Function: const char *PyUnicode_AsUTF8 (PyObject *unicode)

     As *note PyUnicode_AsUTF8AndSize(): 8a0, but does not store the
     size.

          Warning: This function does not have any special behavior for
          null characters(1) embedded within 'unicode'.  As a result,
          strings containing null characters will remain in the returned
          string, which some C functions might interpret as the end of
          the string, leading to truncation.  If truncation is an issue,
          it is recommended to use *note PyUnicode_AsUTF8AndSize(): 8a0.
          instead.

     Added in version 3.3.

     Changed in version 3.7: The return type is now ‘const char *’
     rather of ‘char *’.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Null_character


File: python.info,  Node: UTF-32 Codecs,  Next: UTF-16 Codecs,  Prev: UTF-8 Codecs,  Up: Built-in Codecs

7.8.3.17 UTF-32 Codecs
......................

These are the UTF-32 codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF32 (const char
          *str, Py_ssize_t size, const char *errors, int *byteorder)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Decode 'size' bytes from a UTF-32 encoded buffer string and
     return the corresponding Unicode object.  'errors' (if non-‘NULL’)
     defines the error handling.  It defaults to “strict”.

     If 'byteorder' is non-‘NULL’, the decoder starts decoding using the
     given byte order:

          *byteorder == -1: little endian
          *byteorder == 0:  native order
          *byteorder == 1:  big endian

     If ‘*byteorder’ is zero, and the first four bytes of the input data
     are a byte order mark (BOM), the decoder switches to this byte
     order and the BOM is not copied into the resulting Unicode string.
     If ‘*byteorder’ is ‘-1’ or ‘1’, any byte order mark is copied to
     the output.

     After completion, '*byteorder' is set to the current byte order at
     the end of input data.

     If 'byteorder' is ‘NULL’, the codec starts in native order mode.

     Return ‘NULL’ if an exception was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF32Stateful
          (const char *str, Py_ssize_t size, const char *errors, int
          *byteorder, Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  If 'consumed' is ‘NULL’, behave like *note
     PyUnicode_DecodeUTF32(): 4dcf.  If 'consumed' is not ‘NULL’, *note
     PyUnicode_DecodeUTF32Stateful(): 4dd0. will not treat trailing
     incomplete UTF-32 byte sequences (such as a number of bytes not
     divisible by four) as an error.  Those bytes will not be decoded
     and the number of bytes that have been decoded will be stored in
     'consumed'.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsUTF32String (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a Python byte string using the UTF-32 encoding in
     native byte order.  The string always starts with a BOM mark.
     Error handling is “strict”.  Return ‘NULL’ if an exception was
     raised by the codec.


File: python.info,  Node: UTF-16 Codecs,  Next: UTF-7 Codecs,  Prev: UTF-32 Codecs,  Up: Built-in Codecs

7.8.3.18 UTF-16 Codecs
......................

These are the UTF-16 codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF16 (const char
          *str, Py_ssize_t size, const char *errors, int *byteorder)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Decode 'size' bytes from a UTF-16 encoded buffer string and
     return the corresponding Unicode object.  'errors' (if non-‘NULL’)
     defines the error handling.  It defaults to “strict”.

     If 'byteorder' is non-‘NULL’, the decoder starts decoding using the
     given byte order:

          *byteorder == -1: little endian
          *byteorder == 0:  native order
          *byteorder == 1:  big endian

     If ‘*byteorder’ is zero, and the first two bytes of the input data
     are a byte order mark (BOM), the decoder switches to this byte
     order and the BOM is not copied into the resulting Unicode string.
     If ‘*byteorder’ is ‘-1’ or ‘1’, any byte order mark is copied to
     the output (where it will result in either a ‘\ufeff’ or a ‘\ufffe’
     character).

     After completion, ‘*byteorder’ is set to the current byte order at
     the end of input data.

     If 'byteorder' is ‘NULL’, the codec starts in native order mode.

     Return ‘NULL’ if an exception was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF16Stateful
          (const char *str, Py_ssize_t size, const char *errors, int
          *byteorder, Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  If 'consumed' is ‘NULL’, behave like *note
     PyUnicode_DecodeUTF16(): 4dcd.  If 'consumed' is not ‘NULL’, *note
     PyUnicode_DecodeUTF16Stateful(): 4dce. will not treat trailing
     incomplete UTF-16 byte sequences (such as an odd number of bytes or
     a split surrogate pair) as an error.  Those bytes will not be
     decoded and the number of bytes that have been decoded will be
     stored in 'consumed'.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsUTF16String (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a Python byte string using the UTF-16 encoding in
     native byte order.  The string always starts with a BOM mark.
     Error handling is “strict”.  Return ‘NULL’ if an exception was
     raised by the codec.


File: python.info,  Node: UTF-7 Codecs,  Next: Unicode-Escape Codecs,  Prev: UTF-16 Codecs,  Up: Built-in Codecs

7.8.3.19 UTF-7 Codecs
.....................

These are the UTF-7 codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF7 (const char
          *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     UTF-7 encoded string 'str'.  Return ‘NULL’ if an exception was
     raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUTF7Stateful
          (const char *str, Py_ssize_t size, const char *errors,
          Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  If 'consumed' is ‘NULL’, behave like *note
     PyUnicode_DecodeUTF7(): 4dd1.  If 'consumed' is not ‘NULL’,
     trailing incomplete UTF-7 base-64 sections will not be treated as
     an error.  Those bytes will not be decoded and the number of bytes
     that have been decoded will be stored in 'consumed'.


File: python.info,  Node: Unicode-Escape Codecs,  Next: Raw-Unicode-Escape Codecs,  Prev: UTF-7 Codecs,  Up: Built-in Codecs

7.8.3.20 Unicode-Escape Codecs
..............................

These are the “Unicode Escape” codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeUnicodeEscape
          (const char *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     Unicode-Escape encoded string 'str'.  Return ‘NULL’ if an exception
     was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsUnicodeEscapeString
          (PyObject *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using Unicode-Escape and return the
     result as a bytes object.  Error handling is “strict”.  Return
     ‘NULL’ if an exception was raised by the codec.


File: python.info,  Node: Raw-Unicode-Escape Codecs,  Next: Latin-1 Codecs,  Prev: Unicode-Escape Codecs,  Up: Built-in Codecs

7.8.3.21 Raw-Unicode-Escape Codecs
..................................

These are the “Raw Unicode Escape” codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeRawUnicodeEscape
          (const char *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     Raw-Unicode-Escape encoded string 'str'.  Return ‘NULL’ if an
     exception was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsRawUnicodeEscapeString
          (PyObject *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using Raw-Unicode-Escape and return
     the result as a bytes object.  Error handling is “strict”.  Return
     ‘NULL’ if an exception was raised by the codec.


File: python.info,  Node: Latin-1 Codecs,  Next: ASCII Codecs,  Prev: Raw-Unicode-Escape Codecs,  Up: Built-in Codecs

7.8.3.22 Latin-1 Codecs
.......................

These are the Latin-1 codec APIs: Latin-1 corresponds to the first 256
Unicode ordinals and only these are accepted by the codecs during
encoding.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeLatin1 (const char
          *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     Latin-1 encoded string 'str'.  Return ‘NULL’ if an exception was
     raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsLatin1String (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using Latin-1 and return the result
     as Python bytes object.  Error handling is “strict”.  Return ‘NULL’
     if an exception was raised by the codec.


File: python.info,  Node: ASCII Codecs,  Next: Character Map Codecs,  Prev: Latin-1 Codecs,  Up: Built-in Codecs

7.8.3.23 ASCII Codecs
.....................

These are the ASCII codec APIs.  Only 7-bit ASCII data is accepted.  All
other codes generate errors.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeASCII (const char
          *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     ASCII encoded string 'str'.  Return ‘NULL’ if an exception was
     raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsASCIIString (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using ASCII and return the result as
     Python bytes object.  Error handling is “strict”.  Return ‘NULL’ if
     an exception was raised by the codec.


File: python.info,  Node: Character Map Codecs,  Next: MBCS codecs for Windows,  Prev: ASCII Codecs,  Up: Built-in Codecs

7.8.3.24 Character Map Codecs
.............................

This codec is special in that it can be used to implement many different
codecs (and this is in fact what was done to obtain most of the standard
codecs included in the ‘encodings’ package).  The codec uses mappings to
encode and decode characters.  The mapping objects provided must support
the *note __getitem__(): 283. mapping interface; dictionaries and
sequences work well.

These are the mapping codec APIs:

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeCharmap (const
          char *str, Py_ssize_t length, PyObject *mapping, const char
          *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Unicode object by decoding 'size' bytes of the
     encoded string 'str' using the given 'mapping' object.  Return
     ‘NULL’ if an exception was raised by the codec.

     If 'mapping' is ‘NULL’, Latin-1 decoding will be applied.  Else
     'mapping' must map bytes ordinals (integers in the range from 0 to
     255) to Unicode strings, integers (which are then interpreted as
     Unicode ordinals) or ‘None’.  Unmapped data bytes – ones which
     cause a *note LookupError: 238a, as well as ones which get mapped
     to ‘None’, ‘0xFFFE’ or ‘'\ufffe'’, are treated as undefined
     mappings and cause an error.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsCharmapString
          (PyObject *unicode, PyObject *mapping)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Encode a Unicode object using the given 'mapping' object and
     return the result as a bytes object.  Error handling is “strict”.
     Return ‘NULL’ if an exception was raised by the codec.

     The 'mapping' object must map Unicode ordinal integers to bytes
     objects, integers in the range from 0 to 255 or ‘None’.  Unmapped
     character ordinals (ones which cause a *note LookupError: 238a.) as
     well as mapped to ‘None’ are treated as “undefined mapping” and
     cause an error.

The following codec API is special in that maps Unicode to Unicode.

 -- C Function: *note PyObject: 33a. *PyUnicode_Translate (PyObject
          *unicode, PyObject *table, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Translate a string by applying a character mapping table to
     it and return the resulting Unicode object.  Return ‘NULL’ if an
     exception was raised by the codec.

     The mapping table must map Unicode ordinal integers to Unicode
     ordinal integers or ‘None’ (causing deletion of the character).

     Mapping tables need only provide the *note __getitem__(): 283.
     interface; dictionaries and sequences work well.  Unmapped
     character ordinals (ones which cause a *note LookupError: 238a.)
     are left untouched and are copied as-is.

     'errors' has the usual meaning for codecs.  It may be ‘NULL’ which
     indicates to use the default error handling.


File: python.info,  Node: MBCS codecs for Windows,  Prev: Character Map Codecs,  Up: Built-in Codecs

7.8.3.25 MBCS codecs for Windows
................................

These are the MBCS codec APIs.  They are currently only available on
Windows and use the Win32 MBCS converters to implement the conversions.
Note that MBCS (or DBCS) is a class of encodings, not just one.  The
target encoding is defined by the user settings on the machine running
the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeMBCS (const char
          *str, Py_ssize_t size, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     on Windows since version 3.7.'  Create a Unicode object by decoding
     'size' bytes of the MBCS encoded string 'str'.  Return ‘NULL’ if an
     exception was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeMBCSStateful
          (const char *str, Py_ssize_t size, const char *errors,
          Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     on Windows since version 3.7.'  If 'consumed' is ‘NULL’, behave
     like *note PyUnicode_DecodeMBCS(): 4dca.  If 'consumed' is not
     ‘NULL’, *note PyUnicode_DecodeMBCSStateful(): 4dcb. will not decode
     trailing lead byte and the number of bytes that have been decoded
     will be stored in 'consumed'.

 -- C Function: *note PyObject: 33a. *PyUnicode_DecodeCodePageStateful
          (int code_page, const char *str, Py_ssize_t size, const char
          *errors, Py_ssize_t *consumed)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     on Windows since version 3.7.'  Similar to *note
     PyUnicode_DecodeMBCSStateful(): 4dcb, except uses the code page
     specified by 'code_page'.

 -- C Function: *note PyObject: 33a. *PyUnicode_AsMBCSString (PyObject
          *unicode)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     on Windows since version 3.7.'  Encode a Unicode object using MBCS
     and return the result as Python bytes object.  Error handling is
     “strict”.  Return ‘NULL’ if an exception was raised by the codec.

 -- C Function: *note PyObject: 33a. *PyUnicode_EncodeCodePage (int
          code_page, PyObject *unicode, const char *errors)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     on Windows since version 3.7.'  Encode the Unicode object using the
     specified code page and return a Python bytes object.  Return
     ‘NULL’ if an exception was raised by the codec.  Use ‘CP_ACP’ code
     page to get the MBCS encoder.

     Added in version 3.3.


File: python.info,  Node: Methods and Slot Functions,  Prev: Built-in Codecs,  Up: Unicode Objects and Codecs

7.8.3.26 Methods and Slot Functions
...................................

The following APIs are capable of handling Unicode objects and strings
on input (we refer to them as strings in the descriptions) and return
Unicode objects or integers as appropriate.

They all return ‘NULL’ or ‘-1’ if an exception occurs.

 -- C Function: *note PyObject: 33a. *PyUnicode_Concat (PyObject *left,
          PyObject *right)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Concat two strings giving a new Unicode string.

 -- C Function: *note PyObject: 33a. *PyUnicode_Split (PyObject
          *unicode, PyObject *sep, Py_ssize_t maxsplit)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Split a string giving a list of Unicode strings.  If 'sep'
     is ‘NULL’, splitting will be done at all whitespace substrings.
     Otherwise, splits occur at the given separator.  At most 'maxsplit'
     splits will be done.  If negative, no limit is set.  Separators are
     not included in the resulting list.

     On error, return ‘NULL’ with an exception set.

     Equivalent to *note str.split(): ede.

 -- C Function: *note PyObject: 33a. *PyUnicode_RSplit (PyObject
          *unicode, PyObject *sep, Py_ssize_t maxsplit)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Similar to *note PyUnicode_Split(): 4ddf, but splitting will
     be done beginning at the end of the string.

     On error, return ‘NULL’ with an exception set.

     Equivalent to *note str.rsplit(): 129c.

 -- C Function: *note PyObject: 33a. *PyUnicode_Splitlines (PyObject
          *unicode, int keepends)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Split a Unicode string at line breaks, returning a list of
     Unicode strings.  CRLF is considered to be one line break.  If
     'keepends' is ‘0’, the Line break characters are not included in
     the resulting strings.

 -- C Function: *note PyObject: 33a. *PyUnicode_Partition (PyObject
          *unicode, PyObject *sep)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Split a Unicode string at the first occurrence of 'sep', and
     return a 3-tuple containing the part before the separator, the
     separator itself, and the part after the separator.  If the
     separator is not found, return a 3-tuple containing the string
     itself, followed by two empty strings.

     'sep' must not be empty.

     On error, return ‘NULL’ with an exception set.

     Equivalent to *note str.partition(): edf.

 -- C Function: *note PyObject: 33a. *PyUnicode_RPartition (PyObject
          *unicode, PyObject *sep)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Similar to *note PyUnicode_Partition(): 1674, but split a
     Unicode string at the last occurrence of 'sep'.  If the separator
     is not found, return a 3-tuple containing two empty strings,
     followed by the string itself.

     'sep' must not be empty.

     On error, return ‘NULL’ with an exception set.

     Equivalent to *note str.rpartition(): 129f.

 -- C Function: *note PyObject: 33a. *PyUnicode_Join (PyObject
          *separator, PyObject *seq)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Join a sequence of strings using the given 'separator' and
     return the resulting Unicode string.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_Tailmatch (PyObject
          *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end,
          int direction)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if 'substr'
     matches ‘unicode[start:end]’ at the given tail end ('direction' ==
     ‘-1’ means to do a prefix match, 'direction' == ‘1’ a suffix
     match), ‘0’ otherwise.  Return ‘-1’ if an error occurred.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_Find (PyObject
          *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end,
          int direction)
     ' Part of the *note Stable ABI: 556.'  Return the first position of
     'substr' in ‘unicode[start:end]’ using the given 'direction'
     ('direction' == ‘1’ means to do a forward search, 'direction' ==
     ‘-1’ a backward search).  The return value is the index of the
     first match; a value of ‘-1’ indicates that no match was found, and
     ‘-2’ indicates that an error occurred and an exception has been
     set.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_FindChar (PyObject
          *unicode, Py_UCS4 ch, Py_ssize_t start, Py_ssize_t end, int
          direction)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return
     the first position of the character 'ch' in ‘unicode[start:end]’
     using the given 'direction' ('direction' == ‘1’ means to do a
     forward search, 'direction' == ‘-1’ a backward search).  The return
     value is the index of the first match; a value of ‘-1’ indicates
     that no match was found, and ‘-2’ indicates that an error occurred
     and an exception has been set.

     Added in version 3.3.

     Changed in version 3.7: 'start' and 'end' are now adjusted to
     behave like ‘unicode[start:end]’.

 -- C Function: *note Py_ssize_t: a6e. PyUnicode_Count (PyObject
          *unicode, PyObject *substr, Py_ssize_t start, Py_ssize_t end)
     ' Part of the *note Stable ABI: 556.'  Return the number of
     non-overlapping occurrences of 'substr' in ‘unicode[start:end]’.
     Return ‘-1’ if an error occurred.

 -- C Function: *note PyObject: 33a. *PyUnicode_Replace (PyObject
          *unicode, PyObject *substr, PyObject *replstr, Py_ssize_t
          maxcount)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Replace at most 'maxcount' occurrences of 'substr' in
     'unicode' with 'replstr' and return the resulting Unicode object.
     'maxcount' == ‘-1’ means replace all occurrences.

 -- C Function: int PyUnicode_Compare (PyObject *left, PyObject *right)
     ' Part of the *note Stable ABI: 556.'  Compare two strings and
     return ‘-1’, ‘0’, ‘1’ for less than, equal, and greater than,
     respectively.

     This function returns ‘-1’ upon failure, so one should call *note
     PyErr_Occurred(): 1a55. to check for errors.

 -- C Function: int PyUnicode_EqualToUTF8AndSize (PyObject *unicode,
          const char *string, Py_ssize_t size)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Compare
     a Unicode object with a char buffer which is interpreted as being
     UTF-8 or ASCII encoded and return true (‘1’) if they are equal, or
     false (‘0’) otherwise.  If the Unicode object contains surrogate
     code points (‘U+D800’ - ‘U+DFFF’) or the C string is not valid
     UTF-8, false (‘0’) is returned.

     This function does not raise exceptions.

     Added in version 3.13.

 -- C Function: int PyUnicode_EqualToUTF8 (PyObject *unicode, const char
          *string)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note PyUnicode_EqualToUTF8AndSize(): 379, but compute 'string'
     length using ‘strlen()’.  If the Unicode object contains null
     characters, false (‘0’) is returned.

     Added in version 3.13.

 -- C Function: int PyUnicode_CompareWithASCIIString (PyObject *unicode,
          const char *string)
     ' Part of the *note Stable ABI: 556.'  Compare a Unicode object,
     'unicode', with 'string' and return ‘-1’, ‘0’, ‘1’ for less than,
     equal, and greater than, respectively.  It is best to pass only
     ASCII-encoded strings, but the function interprets the input string
     as ISO-8859-1 if it contains non-ASCII characters.

     This function does not raise exceptions.

 -- C Function: *note PyObject: 33a. *PyUnicode_RichCompare (PyObject
          *left, PyObject *right, int op)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Rich compare two Unicode strings and return one of the
     following:

        * ‘NULL’ in case an exception was raised

        * *note Py_True: 4fc2. or *note Py_False: 4fc1. for successful
          comparisons

        * *note Py_NotImplemented: 4f37. in case the type combination is
          unknown

     Possible values for 'op' are *note Py_GT: 4f3e, *note Py_GE: 4f3f,
     *note Py_EQ: 4f3c, *note Py_NE: 4f3d, *note Py_LT: 4f3a, and *note
     Py_LE: 4f3b.

 -- C Function: *note PyObject: 33a. *PyUnicode_Format (PyObject
          *format, PyObject *args)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new string object from 'format' and 'args'; this is
     analogous to ‘format % args’.

 -- C Function: int PyUnicode_Contains (PyObject *unicode, PyObject
          *substr)
     ' Part of the *note Stable ABI: 556.'  Check whether 'substr' is
     contained in 'unicode' and return true or false accordingly.

     'substr' has to coerce to a one element Unicode string.  ‘-1’ is
     returned if there was an error.

 -- C Function: void PyUnicode_InternInPlace (PyObject **p_unicode)
     ' Part of the *note Stable ABI: 556.'  Intern the argument **note
     p_unicode: 8b9. in place.  The argument must be the address of a
     pointer variable pointing to a Python Unicode string object.  If
     there is an existing interned string that is the same as
     *p_unicode, it sets *p_unicode to it (releasing the reference to
     the old string object and creating a new *note strong reference:
     33e. to the interned string object), otherwise it leaves *p_unicode
     alone and interns it.

     (Clarification: even though there is a lot of talk about
     references, think of this function as reference-neutral.  You must
     own the object you pass in; after the call you no longer own the
     passed-in reference, but you newly own the result.)

     This function never raises an exception.  On error, it leaves its
     argument unchanged without interning it.

     Instances of subclasses of *note str: 44f. may not be interned,
     that is, *note PyUnicode_CheckExact: 5006.(**note p_unicode: 8b9.)
     must be true.  If it is not, then – as with any other error – the
     argument is left unchanged.

     Note that interned strings are not “immortal”.  You must keep a
     reference to the result to benefit from interning.

 -- C Function: *note PyObject: 33a. *PyUnicode_InternFromString (const
          char *str)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  A combination of *note PyUnicode_FromString(): 4dda. and
     *note PyUnicode_InternInPlace(): 8b9, meant for statically
     allocated strings.

     Return a new (“owned”) reference to either a new Unicode string
     object that has been interned, or an earlier interned string object
     with the same value.

     Python may keep a reference to the result, or make it *note
     immortal: 45dd, preventing it from being garbage-collected
     promptly.  For interning an unbounded number of different strings,
     such as ones coming from user input, prefer calling *note
     PyUnicode_FromString(): 4dda. and *note PyUnicode_InternInPlace():
     8b9. directly.


File: python.info,  Node: Tuple Objects,  Next: Struct Sequence Objects,  Prev: Unicode Objects and Codecs,  Up: Sequence Objects

7.8.3.27 Tuple Objects
......................

 -- C Type: type PyTupleObject

     This subtype of *note PyObject: 33a. represents a Python tuple
     object.

 -- C Variable: *note PyTypeObject: aba. PyTuple_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python tuple type; it is the same
     object as *note tuple: 373. in the Python layer.

 -- C Function: int PyTuple_Check (PyObject *p)

     Return true if 'p' is a tuple object or an instance of a subtype of
     the tuple type.  This function always succeeds.

 -- C Function: int PyTuple_CheckExact (PyObject *p)

     Return true if 'p' is a tuple object, but not an instance of a
     subtype of the tuple type.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyTuple_New (Py_ssize_t len)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new tuple object of size 'len', or ‘NULL’ with an
     exception set on failure.

 -- C Function: *note PyObject: 33a. *PyTuple_Pack (Py_ssize_t n, ...)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new tuple object of size 'n', or ‘NULL’ with an
     exception set on failure.  The tuple values are initialized to the
     subsequent 'n' C arguments pointing to Python objects.
     ‘PyTuple_Pack(2, a, b)’ is equivalent to ‘Py_BuildValue("(OO)", a,
     b)’.

 -- C Function: *note Py_ssize_t: a6e. PyTuple_Size (PyObject *p)
     ' Part of the *note Stable ABI: 556.'  Take a pointer to a tuple
     object, and return the size of that tuple.  On error, return ‘-1’
     with an exception set.

 -- C Function: *note Py_ssize_t: a6e. PyTuple_GET_SIZE (PyObject *p)

     Like *note PyTuple_Size(): 4da0, but without error checking.

 -- C Function: *note PyObject: 33a. *PyTuple_GetItem (PyObject *p,
          Py_ssize_t pos)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return the object at position 'pos' in the tuple pointed to
     by 'p'.  If 'pos' is negative or out of bounds, return ‘NULL’ and
     set an *note IndexError: 1585. exception.

     The returned reference is borrowed from the tuple 'p' (that is: it
     is only valid as long as you hold a reference to 'p').  To get a
     *note strong reference: 33e, use *note
     Py_NewRef(PyTuple_GetItem(...)): 8a1. or *note
     PySequence_GetItem(): 1be5.

 -- C Function: *note PyObject: 33a. *PyTuple_GET_ITEM (PyObject *p,
          Py_ssize_t pos)
     'Return value: Borrowed reference.'  Like *note PyTuple_GetItem():
     4b82, but does no checking of its arguments.

 -- C Function: *note PyObject: 33a. *PyTuple_GetSlice (PyObject *p,
          Py_ssize_t low, Py_ssize_t high)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return the slice of the tuple pointed to by 'p' between
     'low' and 'high', or ‘NULL’ with an exception set on failure.

     This is the equivalent of the Python expression ‘p[low:high]’.
     Indexing from the end of the tuple is not supported.

 -- C Function: int PyTuple_SetItem (PyObject *p, Py_ssize_t pos,
          PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Insert a reference to object
     'o' at position 'pos' of the tuple pointed to by 'p'.  Return ‘0’
     on success.  If 'pos' is out of bounds, return ‘-1’ and set an
     *note IndexError: 1585. exception.

          Note: This function “steals” a reference to 'o' and discards a
          reference to an item already in the tuple at the affected
          position.

 -- C Function: void PyTuple_SET_ITEM (PyObject *p, Py_ssize_t pos,
          PyObject *o)

     Like *note PyTuple_SetItem(): 4b83, but does no error checking, and
     should 'only' be used to fill in brand new tuples.

     Bounds checking is performed as an assertion if Python is built in
     *note debug mode: 1f9. or *note with assertions: 38f.

          Note: This function “steals” a reference to 'o', and, unlike
          *note PyTuple_SetItem(): 4b83, does 'not' discard a reference
          to any item that is being replaced; any reference in the tuple
          at position 'pos' will be leaked.

 -- C Function: int _PyTuple_Resize (PyObject **p, Py_ssize_t newsize)

     Can be used to resize a tuple.  'newsize' will be the new length of
     the tuple.  Because tuples are 'supposed' to be immutable, this
     should only be used if there is only one reference to the object.
     Do 'not' use this if the tuple may already be known to some other
     part of the code.  The tuple will always grow or shrink at the end.
     Think of this as destroying the old tuple and creating a new one,
     only more efficiently.  Returns ‘0’ on success.  Client code should
     never assume that the resulting value of ‘*p’ will be the same as
     before calling this function.  If the object referenced by ‘*p’ is
     replaced, the original ‘*p’ is destroyed.  On failure, returns ‘-1’
     and sets ‘*p’ to ‘NULL’, and raises *note MemoryError: 15ab. or
     *note SystemError: 578.


File: python.info,  Node: Struct Sequence Objects,  Next: List Objects,  Prev: Tuple Objects,  Up: Sequence Objects

7.8.3.28 Struct Sequence Objects
................................

Struct sequence objects are the C equivalent of *note namedtuple(): 1ca.
objects, i.e.  a sequence whose items can also be accessed through
attributes.  To create a struct sequence, you first have to create a
specific struct sequence type.

 -- C Function: *note PyTypeObject: aba. *PyStructSequence_NewType
          (PyStructSequence_Desc *desc)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a new struct sequence type from the data in 'desc',
     described below.  Instances of the resulting type can be created
     with *note PyStructSequence_New(): 4d80.

     Return ‘NULL’ with an exception set on failure.

 -- C Function: void PyStructSequence_InitType (PyTypeObject *type,
          PyStructSequence_Desc *desc)

     Initializes a struct sequence type 'type' from 'desc' in place.

 -- C Function: int PyStructSequence_InitType2 (PyTypeObject *type,
          PyStructSequence_Desc *desc)

     Like *note PyStructSequence_InitType(): 103e, but returns ‘0’ on
     success and ‘-1’ with an exception set on failure.

     Added in version 3.4.

 -- C Type: type PyStructSequence_Desc
     ' Part of the *note Stable ABI: 556. (including all members).'
     Contains the meta information of a struct sequence type to create.

      -- C Member: const char *name

          Fully qualified name of the type; null-terminated UTF-8
          encoded.  The name must contain the module name.

      -- C Member: const char *doc

          Pointer to docstring for the type or ‘NULL’ to omit.

      -- C Member: *note PyStructSequence_Field: bd8. *fields

          Pointer to ‘NULL’-terminated array with field names of the new
          type.

      -- C Member: int n_in_sequence

          Number of fields visible to the Python side (if used as
          tuple).

 -- C Type: type PyStructSequence_Field
     ' Part of the *note Stable ABI: 556. (including all members).'
     Describes a field of a struct sequence.  As a struct sequence is
     modeled as a tuple, all fields are typed as *note PyObject: 33a.*.
     The index in the *note fields: 503c. array of the *note
     PyStructSequence_Desc: bd9. determines which field of the struct
     sequence is described.

      -- C Member: const char *name

          Name for the field or ‘NULL’ to end the list of named fields,
          set to *note PyStructSequence_UnnamedField: 98c. to leave
          unnamed.

      -- C Member: const char *doc

          Field docstring or ‘NULL’ to omit.

 -- C Variable: const char *const PyStructSequence_UnnamedField
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Special
     value for a field name to leave it unnamed.

     Changed in version 3.9: The type was changed from ‘char *’.

 -- C Function: *note PyObject: 33a. *PyStructSequence_New (PyTypeObject
          *type)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Creates an instance of 'type', which must have been created
     with *note PyStructSequence_NewType(): 4d81.

     Return ‘NULL’ with an exception set on failure.

 -- C Function: *note PyObject: 33a. *PyStructSequence_GetItem (PyObject
          *p, Py_ssize_t pos)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return the object at position 'pos' in the struct sequence
     pointed to by 'p'.

     Bounds checking is performed as an assertion if Python is built in
     *note debug mode: 1f9. or *note with assertions: 38f.

 -- C Function: *note PyObject: 33a. *PyStructSequence_GET_ITEM
          (PyObject *p, Py_ssize_t pos)
     'Return value: Borrowed reference.'  Alias to *note
     PyStructSequence_GetItem(): 4d7f.

     Changed in version 3.13: Now implemented as an alias to *note
     PyStructSequence_GetItem(): 4d7f.

 -- C Function: void PyStructSequence_SetItem (PyObject *p, Py_ssize_t
          pos, PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Sets the field at index
     'pos' of the struct sequence 'p' to value 'o'.  Like *note
     PyTuple_SET_ITEM(): 390, this should only be used to fill in brand
     new instances.

     Bounds checking is performed as an assertion if Python is built in
     *note debug mode: 1f9. or *note with assertions: 38f.

          Note: This function “steals” a reference to 'o'.

 -- C Function: void PyStructSequence_SET_ITEM (PyObject *p, Py_ssize_t
          *pos, PyObject *o)

     Alias to *note PyStructSequence_SetItem(): 4d82.

     Changed in version 3.13: Now implemented as an alias to *note
     PyStructSequence_SetItem(): 4d82.


File: python.info,  Node: List Objects,  Prev: Struct Sequence Objects,  Up: Sequence Objects

7.8.3.29 List Objects
.....................

 -- C Type: type PyListObject

     This subtype of *note PyObject: 33a. represents a Python list
     object.

 -- C Variable: *note PyTypeObject: aba. PyList_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python list type.  This is the
     same object as *note list: 614. in the Python layer.

 -- C Function: int PyList_Check (PyObject *p)

     Return true if 'p' is a list object or an instance of a subtype of
     the list type.  This function always succeeds.

 -- C Function: int PyList_CheckExact (PyObject *p)

     Return true if 'p' is a list object, but not an instance of a
     subtype of the list type.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyList_New (Py_ssize_t len)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new list of length 'len' on success, or ‘NULL’ on
     failure.

          Note: If 'len' is greater than zero, the returned list
          object’s items are set to ‘NULL’.  Thus you cannot use
          abstract API functions such as *note PySequence_SetItem():
          1be6. or expose the object to Python code before setting all
          items to a real object with *note PyList_SetItem(): 167d. or
          *note PyList_SET_ITEM(): 391.  The following APIs are safe
          APIs before the list is fully initialized: ‘PyList_SetItem()’
          and ‘PyList_SET_ITEM()’.

 -- C Function: *note Py_ssize_t: a6e. PyList_Size (PyObject *list)
     ' Part of the *note Stable ABI: 556.'

     Return the length of the list object in 'list'; this is equivalent
     to ‘len(list)’ on a list object.

 -- C Function: *note Py_ssize_t: a6e. PyList_GET_SIZE (PyObject *list)

     Similar to *note PyList_Size(): 1468, but without error checking.

 -- C Function: *note PyObject: 33a. *PyList_GetItemRef (PyObject *list,
          Py_ssize_t index)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.13.'  Return the object at position 'index' in the
     list pointed to by 'list'.  The position must be non-negative;
     indexing from the end of the list is not supported.  If 'index' is
     out of bounds (‘<0 or >=len(list)’), return ‘NULL’ and set an *note
     IndexError: 1585. exception.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyList_GetItem (PyObject *list,
          Py_ssize_t index)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Like *note PyList_GetItemRef(): 35c, but returns a *note
     borrowed reference: 33f. instead of a *note strong reference: 33e.

 -- C Function: *note PyObject: 33a. *PyList_GET_ITEM (PyObject *list,
          Py_ssize_t i)
     'Return value: Borrowed reference.'  Similar to *note
     PyList_GetItem(): 35d, but without error checking.

 -- C Function: int PyList_SetItem (PyObject *list, Py_ssize_t index,
          PyObject *item)
     ' Part of the *note Stable ABI: 556.'  Set the item at index
     'index' in list to 'item'.  Return ‘0’ on success.  If 'index' is
     out of bounds, return ‘-1’ and set an *note IndexError: 1585.
     exception.

          Note: This function “steals” a reference to 'item' and
          discards a reference to an item already in the list at the
          affected position.

 -- C Function: void PyList_SET_ITEM (PyObject *list, Py_ssize_t i,
          PyObject *o)

     Macro form of *note PyList_SetItem(): 167d. without error checking.
     This is normally only used to fill in new lists where there is no
     previous content.

     Bounds checking is performed as an assertion if Python is built in
     *note debug mode: 1f9. or *note with assertions: 38f.

          Note: This macro “steals” a reference to 'item', and, unlike
          *note PyList_SetItem(): 167d, does 'not' discard a reference
          to any item that is being replaced; any reference in 'list' at
          position 'i' will be leaked.

 -- C Function: int PyList_Insert (PyObject *list, Py_ssize_t index,
          PyObject *item)
     ' Part of the *note Stable ABI: 556.'  Insert the item 'item' into
     list 'list' in front of index 'index'.  Return ‘0’ if successful;
     return ‘-1’ and set an exception if unsuccessful.  Analogous to
     ‘list.insert(index, item)’.

 -- C Function: int PyList_Append (PyObject *list, PyObject *item)
     ' Part of the *note Stable ABI: 556.'  Append the object 'item' at
     the end of list 'list'.  Return ‘0’ if successful; return ‘-1’ and
     set an exception if unsuccessful.  Analogous to
     ‘list.append(item)’.

 -- C Function: *note PyObject: 33a. *PyList_GetSlice (PyObject *list,
          Py_ssize_t low, Py_ssize_t high)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a list of the objects in 'list' containing the
     objects 'between' 'low' and 'high'.  Return ‘NULL’ and set an
     exception if unsuccessful.  Analogous to ‘list[low:high]’.
     Indexing from the end of the list is not supported.

 -- C Function: int PyList_SetSlice (PyObject *list, Py_ssize_t low,
          Py_ssize_t high, PyObject *itemlist)
     ' Part of the *note Stable ABI: 556.'  Set the slice of 'list'
     between 'low' and 'high' to the contents of 'itemlist'.  Analogous
     to ‘list[low:high] = itemlist’.  The 'itemlist' may be ‘NULL’,
     indicating the assignment of an empty list (slice deletion).
     Return ‘0’ on success, ‘-1’ on failure.  Indexing from the end of
     the list is not supported.

 -- C Function: int PyList_Extend (PyObject *list, PyObject *iterable)

     Extend 'list' with the contents of 'iterable'.  This is the same as
     ‘PyList_SetSlice(list, PY_SSIZE_T_MAX, PY_SSIZE_T_MAX, iterable)’
     and analogous to ‘list.extend(iterable)’ or ‘list += iterable’.

     Raise an exception and return ‘-1’ if 'list' is not a *note list:
     614. object.  Return 0 on success.

     Added in version 3.13.

 -- C Function: int PyList_Clear (PyObject *list)

     Remove all items from 'list'.  This is the same as
     ‘PyList_SetSlice(list, 0, PY_SSIZE_T_MAX, NULL)’ and analogous to
     ‘list.clear()’ or ‘del list[:]’.

     Raise an exception and return ‘-1’ if 'list' is not a *note list:
     614. object.  Return 0 on success.

     Added in version 3.13.

 -- C Function: int PyList_Sort (PyObject *list)
     ' Part of the *note Stable ABI: 556.'  Sort the items of 'list' in
     place.  Return ‘0’ on success, ‘-1’ on failure.  This is equivalent
     to ‘list.sort()’.

 -- C Function: int PyList_Reverse (PyObject *list)
     ' Part of the *note Stable ABI: 556.'  Reverse the items of 'list'
     in place.  Return ‘0’ on success, ‘-1’ on failure.  This is the
     equivalent of ‘list.reverse()’.

 -- C Function: *note PyObject: 33a. *PyList_AsTuple (PyObject *list)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Return a new tuple object containing the contents of 'list';
     equivalent to ‘tuple(list)’.


File: python.info,  Node: Container Objects,  Next: Function Objects<2>,  Prev: Sequence Objects,  Up: Concrete Objects Layer

7.8.4 Container Objects
-----------------------

* Menu:

* Dictionary Objects::
* Set Objects::


File: python.info,  Node: Dictionary Objects,  Next: Set Objects,  Up: Container Objects

7.8.4.1 Dictionary Objects
..........................

 -- C Type: type PyDictObject

     This subtype of *note PyObject: 33a. represents a Python dictionary
     object.

 -- C Variable: *note PyTypeObject: aba. PyDict_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python dictionary type.  This is
     the same object as *note dict: 256. in the Python layer.

 -- C Function: int PyDict_Check (PyObject *p)

     Return true if 'p' is a dict object or an instance of a subtype of
     the dict type.  This function always succeeds.

 -- C Function: int PyDict_CheckExact (PyObject *p)

     Return true if 'p' is a dict object, but not an instance of a
     subtype of the dict type.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyDict_New ()
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new empty dictionary, or ‘NULL’ on failure.

 -- C Function: *note PyObject: 33a. *PyDictProxy_New (PyObject
          *mapping)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a *note types.MappingProxyType: 470. object for a
     mapping which enforces read-only behavior.  This is normally used
     to create a view to prevent modification of the dictionary for
     non-dynamic class types.

 -- C Variable: *note PyTypeObject: aba. PyDictProxy_Type
     ' Part of the *note Stable ABI: 556.'  The type object for mapping
     proxy objects created by *note PyDictProxy_New(): 4c79. and for the
     read-only ‘__dict__’ attribute of many built-in types.  A *note
     PyDictProxy_Type: 4c7a. instance provides a dynamic, read-only view
     of an underlying dictionary: changes to the underlying dictionary
     are reflected in the proxy, but the proxy itself does not support
     mutation operations.  This corresponds to *note
     types.MappingProxyType: 470. in Python.

 -- C Function: void PyDict_Clear (PyObject *p)
     ' Part of the *note Stable ABI: 556.'  Empty an existing dictionary
     of all key-value pairs.

 -- C Function: int PyDict_Contains (PyObject *p, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Determine if dictionary 'p'
     contains 'key'.  If an item in 'p' matches 'key', return ‘1’,
     otherwise return ‘0’.  On error, return ‘-1’.  This is equivalent
     to the Python expression ‘key in p’.

 -- C Function: int PyDict_ContainsString (PyObject *p, const char *key)

     This is the same as *note PyDict_Contains(): 339, but 'key' is
     specified as a const char* UTF-8 encoded bytes string, rather than
     a *note PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyDict_Copy (PyObject *p)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new dictionary that contains the same key-value
     pairs as 'p'.

 -- C Function: int PyDict_SetItem (PyObject *p, PyObject *key, PyObject
          *val)
     ' Part of the *note Stable ABI: 556.'  Insert 'val' into the
     dictionary 'p' with a key of 'key'.  'key' must be *note hashable:
     613.; if it isn’t, *note TypeError: 2c3. will be raised.  Return
     ‘0’ on success or ‘-1’ on failure.  This function 'does not' steal
     a reference to 'val'.

 -- C Function: int PyDict_SetItemString (PyObject *p, const char *key,
          PyObject *val)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyDict_SetItem(): 4b84, but 'key' is specified as a const char*
     UTF-8 encoded bytes string, rather than a *note PyObject: 33a.*.

 -- C Function: int PyDict_DelItem (PyObject *p, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Remove the entry in
     dictionary 'p' with key 'key'.  'key' must be *note hashable: 613.;
     if it isn’t, *note TypeError: 2c3. is raised.  If 'key' is not in
     the dictionary, *note KeyError: 345. is raised.  Return ‘0’ on
     success or ‘-1’ on failure.

 -- C Function: int PyDict_DelItemString (PyObject *p, const char *key)
     ' Part of the *note Stable ABI: 556.'  This is the same as *note
     PyDict_DelItem(): 4c80, but 'key' is specified as a const char*
     UTF-8 encoded bytes string, rather than a *note PyObject: 33a.*.

 -- C Function: int PyDict_GetItemRef (PyObject *p, PyObject *key,
          PyObject **result)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Return a
     new *note strong reference: 33e. to the object from dictionary 'p'
     which has a key 'key':

        * If the key is present, set '*result' to a new *note strong
          reference: 33e. to the value and return ‘1’.

        * If the key is missing, set '*result' to ‘NULL’ and return ‘0’.

        * On error, raise an exception and return ‘-1’.

     Added in version 3.13.

     See also the *note PyObject_GetItem(): 348. function.

 -- C Function: *note PyObject: 33a. *PyDict_GetItem (PyObject *p,
          PyObject *key)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return a *note borrowed reference: 33f. to the object from
     dictionary 'p' which has a key 'key'.  Return ‘NULL’ if the key
     'key' is missing 'without' setting an exception.

          Note: Exceptions that occur while this calls *note __hash__():
          b14. and *note __eq__(): b13. methods are silently ignored.
          Prefer the *note PyDict_GetItemWithError(): 33d. function
          instead.

     Changed in version 3.10: Calling this API without *note GIL: 159.
     held had been allowed for historical reason.  It is no longer
     allowed.

 -- C Function: *note PyObject: 33a. *PyDict_GetItemWithError (PyObject
          *p, PyObject *key)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Variant of *note PyDict_GetItem(): 38a. that does not
     suppress exceptions.  Return ‘NULL’ 'with' an exception set if an
     exception occurred.  Return ‘NULL’ 'without' an exception set if
     the key wasn’t present.

 -- C Function: *note PyObject: 33a. *PyDict_GetItemString (PyObject *p,
          const char *key)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  This is the same as *note PyDict_GetItem(): 38a, but 'key'
     is specified as a const char* UTF-8 encoded bytes string, rather
     than a *note PyObject: 33a.*.

          Note: Exceptions that occur while this calls *note __hash__():
          b14. and *note __eq__(): b13. methods or while creating the
          temporary *note str: 44f. object are silently ignored.  Prefer
          using the *note PyDict_GetItemWithError(): 33d. function with
          your own *note PyUnicode_FromString(): 4dda. 'key' instead.

 -- C Function: int PyDict_GetItemStringRef (PyObject *p, const char
          *key, PyObject **result)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note PyDict_GetItemRef(): 33b, but 'key' is specified as a
     const char* UTF-8 encoded bytes string, rather than a *note
     PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyDict_SetDefault (PyObject *p,
          PyObject *key, PyObject *defaultobj)
     'Return value: Borrowed reference.'  This is the same as the
     Python-level *note dict.setdefault(): 10b7.  If present, it returns
     the value corresponding to 'key' from the dictionary 'p'.  If the
     key is not in the dict, it is inserted with value 'defaultobj' and
     'defaultobj' is returned.  This function evaluates the hash
     function of 'key' only once, instead of evaluating it independently
     for the lookup and the insertion.

     Added in version 3.4.

 -- C Function: int PyDict_SetDefaultRef (PyObject *p, PyObject *key,
          PyObject *default_value, PyObject **result)

     Inserts 'default_value' into the dictionary 'p' with a key of 'key'
     if the key is not already present in the dictionary.  If 'result'
     is not ‘NULL’, then '*result' is set to a *note strong reference:
     33e. to either 'default_value', if the key was not present, or the
     existing value, if 'key' was already present in the dictionary.
     Returns ‘1’ if the key was present and 'default_value' was not
     inserted, or ‘0’ if the key was not present and 'default_value' was
     inserted.  On failure, returns ‘-1’, sets an exception, and sets
     ‘*result’ to ‘NULL’.

     For clarity: if you have a strong reference to 'default_value'
     before calling this function, then after it returns, you hold a
     strong reference to both 'default_value' and '*result' (if it’s not
     ‘NULL’).  These may refer to the same object: in that case you hold
     two separate references to it.

     Added in version 3.13.

 -- C Function: int PyDict_Pop (PyObject *p, PyObject *key, PyObject
          **result)

     Remove 'key' from dictionary 'p' and optionally return the removed
     value.  Do not raise *note KeyError: 345. if the key is missing.

        - If the key is present, set '*result' to a new reference to the
          removed value if 'result' is not ‘NULL’, and return ‘1’.

        - If the key is missing, set '*result' to ‘NULL’ if 'result' is
          not ‘NULL’, and return ‘0’.

        - On error, raise an exception and return ‘-1’.

     Similar to *note dict.pop(): 344, but without the default value and
     not raising *note KeyError: 345. if the key is missing.

     Added in version 3.13.

 -- C Function: int PyDict_PopString (PyObject *p, const char *key,
          PyObject **result)

     Similar to *note PyDict_Pop(): 342, but 'key' is specified as a
     const char* UTF-8 encoded bytes string, rather than a *note
     PyObject: 33a.*.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyDict_Items (PyObject *p)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a *note PyListObject: 4f58. containing all the items
     from the dictionary.

 -- C Function: *note PyObject: 33a. *PyDict_Keys (PyObject *p)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a *note PyListObject: 4f58. containing all the keys
     from the dictionary.

 -- C Function: *note PyObject: 33a. *PyDict_Values (PyObject *p)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a *note PyListObject: 4f58. containing all the values
     from the dictionary 'p'.

 -- C Function: *note Py_ssize_t: a6e. PyDict_Size (PyObject *p)
     ' Part of the *note Stable ABI: 556.'

     Return the number of items in the dictionary.  This is equivalent
     to ‘len(p)’ on a dictionary.

 -- C Function: *note Py_ssize_t: a6e. PyDict_GET_SIZE (PyObject *p)

     Similar to *note PyDict_Size(): 4c87, but without error checking.

 -- C Function: int PyDict_Next (PyObject *p, Py_ssize_t *ppos, PyObject
          **pkey, PyObject **pvalue)
     ' Part of the *note Stable ABI: 556.'  Iterate over all key-value
     pairs in the dictionary 'p'.  The *note Py_ssize_t: a6e. referred
     to by 'ppos' must be initialized to ‘0’ prior to the first call to
     this function to start the iteration; the function returns true for
     each pair in the dictionary, and false once all pairs have been
     reported.  The parameters 'pkey' and 'pvalue' should either point
     to *note PyObject: 33a.* variables that will be filled in with each
     key and value, respectively, or may be ‘NULL’.  Any references
     returned through them are borrowed.  'ppos' should not be altered
     during iteration.  Its value represents offsets within the internal
     dictionary structure, and since the structure is sparse, the
     offsets are not consecutive.

     For example:

          PyObject *key, *value;
          Py_ssize_t pos = 0;

          while (PyDict_Next(self->dict, &pos, &key, &value)) {
              /* do something interesting with the values... */
              ...
          }

     The dictionary 'p' should not be mutated during iteration.  It is
     safe to modify the values of the keys as you iterate over the
     dictionary, but only so long as the set of keys does not change.
     For example:

          PyObject *key, *value;
          Py_ssize_t pos = 0;

          while (PyDict_Next(self->dict, &pos, &key, &value)) {
              long i = PyLong_AsLong(value);
              if (i == -1 && PyErr_Occurred()) {
                  return -1;
              }
              PyObject *o = PyLong_FromLong(i + 1);
              if (o == NULL)
                  return -1;
              if (PyDict_SetItem(self->dict, key, o) < 0) {
                  Py_DECREF(o);
                  return -1;
              }
              Py_DECREF(o);
          }

     The function is not thread-safe in the *note free-threaded: 15b3.
     build without external synchronization.  You can use *note
     Py_BEGIN_CRITICAL_SECTION: 5050. to lock the dictionary while
     iterating over it:

          Py_BEGIN_CRITICAL_SECTION(self->dict);
          while (PyDict_Next(self->dict, &pos, &key, &value)) {
              ...
          }
          Py_END_CRITICAL_SECTION();

 -- C Function: int PyDict_Merge (PyObject *a, PyObject *b, int
          override)
     ' Part of the *note Stable ABI: 556.'  Iterate over mapping object
     'b' adding key-value pairs to dictionary 'a'.  'b' may be a
     dictionary, or any object supporting *note PyMapping_Keys(): bdb.
     and *note PyObject_GetItem(): 348.  If 'override' is true, existing
     pairs in 'a' will be replaced if a matching key is found in 'b',
     otherwise pairs will only be added if there is not a matching key
     in 'a'.  Return ‘0’ on success or ‘-1’ if an exception was raised.

 -- C Function: int PyDict_Update (PyObject *a, PyObject *b)
     ' Part of the *note Stable ABI: 556.'  This is the same as
     ‘PyDict_Merge(a, b, 1)’ in C, and is similar to ‘a.update(b)’ in
     Python except that *note PyDict_Update(): 4c89. doesn’t fall back
     to the iterating over a sequence of key value pairs if the second
     argument has no “keys” attribute.  Return ‘0’ on success or ‘-1’ if
     an exception was raised.

 -- C Function: int PyDict_MergeFromSeq2 (PyObject *a, PyObject *seq2,
          int override)
     ' Part of the *note Stable ABI: 556.'  Update or merge into
     dictionary 'a', from the key-value pairs in 'seq2'.  'seq2' must be
     an iterable object producing iterable objects of length 2, viewed
     as key-value pairs.  In case of duplicate keys, the last wins if
     'override' is true, else the first wins.  Return ‘0’ on success or
     ‘-1’ if an exception was raised.  Equivalent Python (except for the
     return value):

          def PyDict_MergeFromSeq2(a, seq2, override):
              for key, value in seq2:
                  if override or key not in a:
                      a[key] = value

 -- C Function: int PyDict_AddWatcher (PyDict_WatchCallback callback)

     Register 'callback' as a dictionary watcher.  Return a non-negative
     integer id which must be passed to future calls to *note
     PyDict_Watch(): 566.  In case of error (e.g.  no more watcher IDs
     available), return ‘-1’ and set an exception.

     Added in version 3.12.

 -- C Function: int PyDict_ClearWatcher (int watcher_id)

     Clear watcher identified by 'watcher_id' previously returned from
     *note PyDict_AddWatcher(): 565.  Return ‘0’ on success, ‘-1’ on
     error (e.g.  if the given 'watcher_id' was never registered.)

     Added in version 3.12.

 -- C Function: int PyDict_Watch (int watcher_id, PyObject *dict)

     Mark dictionary 'dict' as watched.  The callback granted
     'watcher_id' by *note PyDict_AddWatcher(): 565. will be called when
     'dict' is modified or deallocated.  Return ‘0’ on success or ‘-1’
     on error.

     Added in version 3.12.

 -- C Function: int PyDict_Unwatch (int watcher_id, PyObject *dict)

     Mark dictionary 'dict' as no longer watched.  The callback granted
     'watcher_id' by *note PyDict_AddWatcher(): 565. will no longer be
     called when 'dict' is modified or deallocated.  The dict must
     previously have been watched by this watcher.  Return ‘0’ on
     success or ‘-1’ on error.

     Added in version 3.12.

 -- C Type: type PyDict_WatchEvent

     Enumeration of possible dictionary watcher events:
     ‘PyDict_EVENT_ADDED’, ‘PyDict_EVENT_MODIFIED’,
     ‘PyDict_EVENT_DELETED’, ‘PyDict_EVENT_CLONED’,
     ‘PyDict_EVENT_CLEARED’, or ‘PyDict_EVENT_DEALLOCATED’.

     Added in version 3.12.

 -- C Type: typedef int (*PyDict_WatchCallback)(*note PyDict_WatchEvent:
          5053. event, *note PyObject: 33a. *dict, *note PyObject: 33a.
          *key, *note PyObject: 33a. *new_value)

     Type of a dict watcher callback function.

     If 'event' is ‘PyDict_EVENT_CLEARED’ or ‘PyDict_EVENT_DEALLOCATED’,
     both 'key' and 'new_value' will be ‘NULL’.  If 'event' is
     ‘PyDict_EVENT_ADDED’ or ‘PyDict_EVENT_MODIFIED’, 'new_value' will
     be the new value for 'key'.  If 'event' is ‘PyDict_EVENT_DELETED’,
     'key' is being deleted from the dictionary and 'new_value' will be
     ‘NULL’.

     ‘PyDict_EVENT_CLONED’ occurs when 'dict' was previously empty and
     another dict is merged into it.  To maintain efficiency of this
     operation, per-key ‘PyDict_EVENT_ADDED’ events are not issued in
     this case; instead a single ‘PyDict_EVENT_CLONED’ is issued, and
     'key' will be the source dictionary.

     The callback may inspect but must not modify 'dict'; doing so could
     have unpredictable effects, including infinite recursion.  Do not
     trigger Python code execution in the callback, as it could modify
     the dict as a side effect.

     If 'event' is ‘PyDict_EVENT_DEALLOCATED’, taking a new reference in
     the callback to the about-to-be-destroyed dictionary will resurrect
     it and prevent it from being freed at this time.  When the
     resurrected object is destroyed later, any watcher callbacks active
     at that time will be called again.

     Callbacks occur before the notified modification to 'dict' takes
     place, so the prior state of 'dict' can be inspected.

     If the callback sets an exception, it must return ‘-1’; this
     exception will be printed as an unraisable exception using *note
     PyErr_WriteUnraisable(): 350.  Otherwise it should return ‘0’.

     There may already be a pending exception set on entry to the
     callback.  In this case, the callback should return ‘0’ with the
     same exception still set.  This means the callback may not call any
     other API that can set an exception unless it saves and clears the
     exception state first, and restores it before returning.

     Added in version 3.12.

* Menu:

* Dictionary View Objects::
* Ordered Dictionaries::


File: python.info,  Node: Dictionary View Objects,  Next: Ordered Dictionaries,  Up: Dictionary Objects

7.8.4.2 Dictionary View Objects
...............................

 -- C Function: int PyDictViewSet_Check (PyObject *op)

     Return true if 'op' is a view of a set inside a dictionary.  This
     is currently equivalent to *note PyDictKeys_Check: 5057.(*note op:
     5056.) || *note PyDictItems_Check: 5058.(op).  This function always
     succeeds.

 -- C Variable: *note PyTypeObject: aba. PyDictKeys_Type
     ' Part of the *note Stable ABI: 556.'  Type object for a view of
     dictionary keys.  In Python, this is the type of the object
     returned by *note dict.keys(): 7d1.

 -- C Function: int PyDictKeys_Check (PyObject *op)

     Return true if 'op' is an instance of a dictionary keys view.  This
     function always succeeds.

 -- C Variable: *note PyTypeObject: aba. PyDictValues_Type
     ' Part of the *note Stable ABI: 556.'  Type object for a view of
     dictionary values.  In Python, this is the type of the object
     returned by *note dict.values(): 7d2.

 -- C Function: int PyDictValues_Check (PyObject *op)

     Return true if 'op' is an instance of a dictionary values view.
     This function always succeeds.

 -- C Variable: *note PyTypeObject: aba. PyDictItems_Type
     ' Part of the *note Stable ABI: 556.'  Type object for a view of
     dictionary items.  In Python, this is the type of the object
     returned by *note dict.items(): 7d3.

 -- C Function: int PyDictItems_Check (PyObject *op)

     Return true if 'op' is an instance of a dictionary items view.
     This function always succeeds.


File: python.info,  Node: Ordered Dictionaries,  Prev: Dictionary View Objects,  Up: Dictionary Objects

7.8.4.3 Ordered Dictionaries
............................

Python’s C API provides interface for *note collections.OrderedDict:
5de. from C. Since Python 3.7, dictionaries are ordered by default, so
there is usually little need for these functions; prefer ‘PyDict*’ where
possible.

 -- C Variable: *note PyTypeObject: aba. PyODict_Type

     Type object for ordered dictionaries.  This is the same object as
     *note collections.OrderedDict: 5de. in the Python layer.

 -- C Function: int PyODict_Check (PyObject *od)

     Return true if 'od' is an ordered dictionary object or an instance
     of a subtype of the *note OrderedDict: 5de. type.  This function
     always succeeds.

 -- C Function: int PyODict_CheckExact (PyObject *od)

     Return true if 'od' is an ordered dictionary object, but not an
     instance of a subtype of the *note OrderedDict: 5de. type.  This
     function always succeeds.

 -- C Variable: *note PyTypeObject: aba. PyODictKeys_Type

     Analogous to *note PyDictKeys_Type: 4c78. for ordered dictionaries.

 -- C Variable: *note PyTypeObject: aba. PyODictValues_Type

     Analogous to *note PyDictValues_Type: 4c7e. for ordered
     dictionaries.

 -- C Variable: *note PyTypeObject: aba. PyODictItems_Type

     Analogous to *note PyDictItems_Type: 4c74. for ordered
     dictionaries.

 -- C Function: *note PyObject: 33a. *PyODict_New (void)

     Return a new empty ordered dictionary, or ‘NULL’ on failure.

     This is analogous to *note PyDict_New(): 4c86.

 -- C Function: int PyODict_SetItem (PyObject *od, PyObject *key,
          PyObject *value)

     Insert 'value' into the ordered dictionary 'od' with a key of
     'key'.  Return ‘0’ on success or ‘-1’ with an exception set on
     failure.

     This is analogous to *note PyDict_SetItem(): 4b84.

 -- C Function: int PyODict_DelItem (PyObject *od, PyObject *key)

     Remove the entry in the ordered dictionary 'od' with key 'key'.
     Return ‘0’ on success or ‘-1’ with an exception set on failure.

     This is analogous to *note PyDict_DelItem(): 4c80.

These are *note soft deprecated: 209. aliases to ‘PyDict’ APIs:

‘PyODict’                                              ‘PyDict’
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Macro: PyODict_GetItem (od, key)                 *note PyDict_GetItem(): 38a.
                                                       
                                                       
 -- C Macro: PyODict_GetItemWithError (od, key)        *note PyDict_GetItemWithError(): 33d.
                                                       
                                                       
 -- C Macro: PyODict_GetItemString (od, key)           *note PyDict_GetItemString(): 38b.
                                                       
                                                       
 -- C Macro: PyODict_Contains (od, key)                *note PyDict_Contains(): 339.
                                                       
                                                       
 -- C Macro: PyODict_Size (od)                         *note PyDict_Size(): 4c87.
                                                       
                                                       
 -- C Macro: PyODict_SIZE (od)                         *note PyDict_GET_SIZE(): 504f.
                                                       


File: python.info,  Node: Set Objects,  Prev: Dictionary Objects,  Up: Container Objects

7.8.4.4 Set Objects
...................

This section details the public API for *note set: 5dc. and *note
frozenset: 5dd. objects.  Any functionality not listed below is best
accessed using either the abstract object protocol (including *note
PyObject_CallMethod(): 3a2, *note PyObject_RichCompareBool(): 1b35,
*note PyObject_Hash(): 406, *note PyObject_Repr(): 106c, *note
PyObject_IsTrue(): 4d59, *note PyObject_Print(): 16fa, and *note
PyObject_GetIter(): 4d58.) or the abstract number protocol (including
*note PyNumber_And(): 4d2c, *note PyNumber_Subtract(): 4d45, *note
PyNumber_Or(): 4d40, *note PyNumber_Xor(): 4d47, *note
PyNumber_InPlaceAnd(): 4d31, *note PyNumber_InPlaceSubtract(): 4d39,
*note PyNumber_InPlaceOr(): 4d35, and *note PyNumber_InPlaceXor():
4d3b.).

 -- C Type: type PySetObject

     This subtype of *note PyObject: 33a. is used to hold the internal
     data for both *note set: 5dc. and *note frozenset: 5dd. objects.
     It is like a *note PyDictObject: 3c4. in that it is a fixed size
     for small sets (much like tuple storage) and will point to a
     separate, variable sized block of memory for medium and large sized
     sets (much like list storage).  None of the fields of this
     structure should be considered public and all are subject to
     change.  All access should be done through the documented API
     rather than by manipulating the values in the structure.

 -- C Variable: *note PyTypeObject: aba. PySet_Type
     ' Part of the *note Stable ABI: 556.'  This is an instance of *note
     PyTypeObject: aba. representing the Python *note set: 5dc. type.

 -- C Variable: *note PyTypeObject: aba. PyFrozenSet_Type
     ' Part of the *note Stable ABI: 556.'  This is an instance of *note
     PyTypeObject: aba. representing the Python *note frozenset: 5dd.
     type.

The following type check macros work on pointers to any Python object.
Likewise, the constructor functions work with any iterable Python
object.

 -- C Function: int PySet_Check (PyObject *p)

     Return true if 'p' is a *note set: 5dc. object or an instance of a
     subtype.  This function always succeeds.

 -- C Function: int PyFrozenSet_Check (PyObject *p)

     Return true if 'p' is a *note frozenset: 5dd. object or an instance
     of a subtype.  This function always succeeds.

 -- C Function: int PyAnySet_Check (PyObject *p)

     Return true if 'p' is a *note set: 5dc. object, a *note frozenset:
     5dd. object, or an instance of a subtype.  This function always
     succeeds.

 -- C Function: int PySet_CheckExact (PyObject *p)

     Return true if 'p' is a *note set: 5dc. object but not an instance
     of a subtype.  This function always succeeds.

     Added in version 3.10.

 -- C Function: int PyAnySet_CheckExact (PyObject *p)

     Return true if 'p' is a *note set: 5dc. object or a *note
     frozenset: 5dd. object but not an instance of a subtype.  This
     function always succeeds.

 -- C Function: int PyFrozenSet_CheckExact (PyObject *p)

     Return true if 'p' is a *note frozenset: 5dd. object but not an
     instance of a subtype.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PySet_New (PyObject *iterable)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note set: 5dc. containing objects returned by
     the 'iterable'.  The 'iterable' may be ‘NULL’ to create a new empty
     set.  Return the new set on success or ‘NULL’ on failure.  Raise
     *note TypeError: 2c3. if 'iterable' is not actually iterable.  The
     constructor is also useful for copying a set (‘c=set(s)’).

 -- C Function: *note PyObject: 33a. *PyFrozenSet_New (PyObject
          *iterable)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new *note frozenset: 5dd. containing objects
     returned by the 'iterable'.  The 'iterable' may be ‘NULL’ to create
     a new empty frozenset.  Return the new set on success or ‘NULL’ on
     failure.  Raise *note TypeError: 2c3. if 'iterable' is not actually
     iterable.

The following functions and macros are available for instances of *note
set: 5dc. or *note frozenset: 5dd. or instances of their subtypes.

 -- C Function: *note Py_ssize_t: a6e. PySet_Size (PyObject *anyset)
     ' Part of the *note Stable ABI: 556.'

     Return the length of a *note set: 5dc. or *note frozenset: 5dd.
     object.  Equivalent to ‘len(anyset)’.  Raises a *note SystemError:
     578. if 'anyset' is not a ‘set’, ‘frozenset’, or an instance of a
     subtype.

 -- C Function: *note Py_ssize_t: a6e. PySet_GET_SIZE (PyObject *anyset)

     Macro form of *note PySet_Size(): 1498. without error checking.

 -- C Function: int PySet_Contains (PyObject *anyset, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if found, ‘0’ if
     not found, and ‘-1’ if an error is encountered.  Unlike the Python
     *note __contains__(): 1406. method, this function does not
     automatically convert unhashable sets into temporary frozensets.
     Raise a *note TypeError: 2c3. if the 'key' is unhashable.  Raise
     *note SystemError: 578. if 'anyset' is not a *note set: 5dc, *note
     frozenset: 5dd, or an instance of a subtype.

 -- C Function: int PySet_Add (PyObject *set, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Add 'key' to a *note set:
     5dc. instance.  Also works with *note frozenset: 5dd. instances
     (like *note PyTuple_SetItem(): 4b83. it can be used to fill in the
     values of brand new frozensets before they are exposed to other
     code).  Return ‘0’ on success or ‘-1’ on failure.  Raise a *note
     TypeError: 2c3. if the 'key' is unhashable.  Raise a *note
     MemoryError: 15ab. if there is no room to grow.  Raise a *note
     SystemError: 578. if 'set' is not an instance of ‘set’ or its
     subtype.

The following functions are available for instances of *note set: 5dc.
or its subtypes but not for instances of *note frozenset: 5dd. or its
subtypes.

 -- C Function: int PySet_Discard (PyObject *set, PyObject *key)
     ' Part of the *note Stable ABI: 556.'  Return ‘1’ if found and
     removed, ‘0’ if not found (no action taken), and ‘-1’ if an error
     is encountered.  Does not raise *note KeyError: 345. for missing
     keys.  Raise a *note TypeError: 2c3. if the 'key' is unhashable.
     Unlike the Python *note discard(): 23f7. method, this function does
     not automatically convert unhashable sets into temporary
     frozensets.  Raise *note SystemError: 578. if 'set' is not an
     instance of *note set: 5dc. or its subtype.

 -- C Function: *note PyObject: 33a. *PySet_Pop (PyObject *set)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new reference to an arbitrary object in the 'set',
     and removes the object from the 'set'.  Return ‘NULL’ on failure.
     Raise *note KeyError: 345. if the set is empty.  Raise a *note
     SystemError: 578. if 'set' is not an instance of *note set: 5dc. or
     its subtype.

 -- C Function: int PySet_Clear (PyObject *set)
     ' Part of the *note Stable ABI: 556.'  Empty an existing set of all
     elements.  Return ‘0’ on success.  Return ‘-1’ and raise *note
     SystemError: 578. if 'set' is not an instance of *note set: 5dc. or
     its subtype.


File: python.info,  Node: Function Objects<2>,  Next: Other Objects,  Prev: Container Objects,  Up: Concrete Objects Layer

7.8.5 Function Objects
----------------------

* Menu:

* Function Objects: Function Objects<3>.
* Instance Method Objects::
* Method Objects: Method Objects<2>.
* Cell Objects::
* Code Objects: Code Objects<2>.
* Code Object Flags::
* Extra information::


File: python.info,  Node: Function Objects<3>,  Next: Instance Method Objects,  Up: Function Objects<2>

7.8.5.1 Function Objects
........................

There are a few functions specific to Python functions.

 -- C Type: type PyFunctionObject

     The C structure used for functions.

 -- C Variable: *note PyTypeObject: aba. PyFunction_Type

     This is an instance of *note PyTypeObject: aba. and represents the
     Python function type.  It is exposed to Python programmers as
     ‘types.FunctionType’.

 -- C Function: int PyFunction_Check (PyObject *o)

     Return true if 'o' is a function object (has type *note
     PyFunction_Type: 507a.).  The parameter must not be ‘NULL’.  This
     function always succeeds.

 -- C Function: *note PyObject: 33a. *PyFunction_New (PyObject *code,
          PyObject *globals)
     'Return value: New reference.'  Return a new function object
     associated with the code object 'code'.  'globals' must be a
     dictionary with the global variables accessible to the function.

     The function’s docstring and name are retrieved from the code
     object.  *note __module__: 20ad. is retrieved from 'globals'.  The
     argument defaults, annotations and closure are set to ‘NULL’.
     *note __qualname__: 20ac. is set to the same value as the code
     object’s *note co_qualname: 20ec. field.

 -- C Function: *note PyObject: 33a. *PyFunction_NewWithQualName
          (PyObject *code, PyObject *globals, PyObject *qualname)
     'Return value: New reference.'  As *note PyFunction_New(): 507c,
     but also allows setting the function object’s *note __qualname__:
     20ac. attribute.  'qualname' should be a unicode object or ‘NULL’;
     if ‘NULL’, the ‘__qualname__’ attribute is set to the same value as
     the code object’s *note co_qualname: 20ec. field.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyFunction_GetCode (PyObject *op)
     'Return value: Borrowed reference.'  Return the code object
     associated with the function object 'op'.

 -- C Function: *note PyObject: 33a. *PyFunction_GetGlobals (PyObject
          *op)
     'Return value: Borrowed reference.'  Return the globals dictionary
     associated with the function object 'op'.

 -- C Function: *note PyObject: 33a. *PyFunction_GetModule (PyObject
          *op)
     'Return value: Borrowed reference.'  Return a *note borrowed
     reference: 33f. to the *note __module__: 20ad. attribute of the
     *note function object: 299. 'op'.  It can be 'NULL'.

     This is normally a *note string: 44f. containing the module name,
     but can be set to any other object by Python code.

 -- C Function: *note PyObject: 33a. *PyFunction_GetDefaults (PyObject
          *op)
     'Return value: Borrowed reference.'  Return the argument default
     values of the function object 'op'.  This can be a tuple of
     arguments or ‘NULL’.

 -- C Function: int PyFunction_SetDefaults (PyObject *op, PyObject
          *defaults)

     Set the argument default values for the function object 'op'.
     'defaults' must be ‘Py_None’ or a tuple.

     Raises *note SystemError: 578. and returns ‘-1’ on failure.

 -- C Function: void PyFunction_SetVectorcall (PyFunctionObject *func,
          vectorcallfunc vectorcall)

     Set the vectorcall field of a given function object 'func'.

     Warning: extensions using this API must preserve the behavior of
     the unaltered (default) vectorcall function!

     Added in version 3.12.

 -- C Function: *note PyObject: 33a. *PyFunction_GetKwDefaults (PyObject
          *op)
     'Return value: Borrowed reference.'  Return the keyword-only
     argument default values of the function object 'op'.  This can be a
     dictionary of arguments or ‘NULL’.

 -- C Function: int PyFunction_SetKwDefaults (PyObject *op, PyObject
          *defaults)

     Set the keyword-only argument default values of the function object
     'op'.  'defaults' must be a dictionary of keyword-only arguments or
     ‘Py_None’.

     This function returns ‘0’ on success, and returns ‘-1’ with an
     exception set on failure.

 -- C Function: *note PyObject: 33a. *PyFunction_GetClosure (PyObject
          *op)
     'Return value: Borrowed reference.'  Return the closure associated
     with the function object 'op'.  This can be ‘NULL’ or a tuple of
     cell objects.

 -- C Function: int PyFunction_SetClosure (PyObject *op, PyObject
          *closure)

     Set the closure associated with the function object 'op'.
     'closure' must be ‘Py_None’ or a tuple of cell objects.

     Raises *note SystemError: 578. and returns ‘-1’ on failure.

 -- C Function: *note PyObject: 33a. *PyFunction_GetAnnotations
          (PyObject *op)
     'Return value: Borrowed reference.'  Return the annotations of the
     function object 'op'.  This can be a mutable dictionary or ‘NULL’.

 -- C Function: int PyFunction_SetAnnotations (PyObject *op, PyObject
          *annotations)

     Set the annotations for the function object 'op'.  'annotations'
     must be a dictionary or ‘Py_None’.

     Raises *note SystemError: 578. and returns ‘-1’ on failure.

 -- C Function: *note PyObject: 33a. *PyFunction_GET_CODE (PyObject *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_GLOBALS (PyObject
          *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_MODULE (PyObject
          *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_DEFAULTS (PyObject
          *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_KW_DEFAULTS
          (PyObject *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_CLOSURE (PyObject
          *op)
 -- C Function: *note PyObject: 33a. *PyFunction_GET_ANNOTATIONS
          (PyObject *op)
     'Return value: Borrowed reference.'  These functions are similar to
     their ‘PyFunction_Get*’ counterparts, but do not do type checking.
     Passing anything other than an instance of *note PyFunction_Type:
     507a. is undefined behavior.

 -- C Function: int PyFunction_AddWatcher (PyFunction_WatchCallback
          callback)

     Register 'callback' as a function watcher for the current
     interpreter.  Return an ID which may be passed to *note
     PyFunction_ClearWatcher(): 5090.  In case of error (e.g.  no more
     watcher IDs available), return ‘-1’ and set an exception.

     Added in version 3.12.

 -- C Function: int PyFunction_ClearWatcher (int watcher_id)

     Clear watcher identified by 'watcher_id' previously returned from
     *note PyFunction_AddWatcher(): 508f. for the current interpreter.
     Return ‘0’ on success, or ‘-1’ and set an exception on error (e.g.
     if the given 'watcher_id' was never registered.)

     Added in version 3.12.

 -- C Type: type PyFunction_WatchEvent

          Enumeration of possible function watcher events:

             - ‘PyFunction_EVENT_CREATE’

             - ‘PyFunction_EVENT_DESTROY’

             - ‘PyFunction_EVENT_MODIFY_CODE’

             - ‘PyFunction_EVENT_MODIFY_DEFAULTS’

             - ‘PyFunction_EVENT_MODIFY_KWDEFAULTS’

     Added in version 3.12.

 -- C Type: typedef int (*PyFunction_WatchCallback)(*note
          PyFunction_WatchEvent: 5091. event, *note PyFunctionObject:
          564. *func, *note PyObject: 33a. *new_value)

     Type of a function watcher callback function.

     If 'event' is ‘PyFunction_EVENT_CREATE’ or
     ‘PyFunction_EVENT_DESTROY’ then 'new_value' will be ‘NULL’.
     Otherwise, 'new_value' will hold a *note borrowed reference: 33f.
     to the new value that is about to be stored in 'func' for the
     attribute that is being modified.

     The callback may inspect but must not modify 'func'; doing so could
     have unpredictable effects, including infinite recursion.

     If 'event' is ‘PyFunction_EVENT_CREATE’, then the callback is
     invoked after 'func' has been fully initialized.  Otherwise, the
     callback is invoked before the modification to 'func' takes place,
     so the prior state of 'func' can be inspected.  The runtime is
     permitted to optimize away the creation of function objects when
     possible.  In such cases no event will be emitted.  Although this
     creates the possibility of an observable difference of runtime
     behavior depending on optimization decisions, it does not change
     the semantics of the Python code being executed.

     If 'event' is ‘PyFunction_EVENT_DESTROY’, Taking a reference in the
     callback to the about-to-be-destroyed function will resurrect it,
     preventing it from being freed at this time.  When the resurrected
     object is destroyed later, any watcher callbacks active at that
     time will be called again.

     If the callback sets an exception, it must return ‘-1’; this
     exception will be printed as an unraisable exception using *note
     PyErr_WriteUnraisable(): 350.  Otherwise it should return ‘0’.

     There may already be a pending exception set on entry to the
     callback.  In this case, the callback should return ‘0’ with the
     same exception still set.  This means the callback may not call any
     other API that can set an exception unless it saves and clears the
     exception state first, and restores it before returning.

     Added in version 3.12.


File: python.info,  Node: Instance Method Objects,  Next: Method Objects<2>,  Prev: Function Objects<3>,  Up: Function Objects<2>

7.8.5.2 Instance Method Objects
...............................

An instance method is a wrapper for a *note PyCFunction: 14c7. and the
new way to bind a ‘PyCFunction’ to a class object.  It replaces the
former call ‘PyMethod_New(func, NULL, class)’.

 -- C Variable: *note PyTypeObject: aba. PyInstanceMethod_Type

     This instance of *note PyTypeObject: aba. represents the Python
     instance method type.  It is not exposed to Python programs.

 -- C Function: int PyInstanceMethod_Check (PyObject *o)

     Return true if 'o' is an instance method object (has type *note
     PyInstanceMethod_Type: 5097.).  The parameter must not be ‘NULL’.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyInstanceMethod_New (PyObject
          *func)
     'Return value: New reference.'  Return a new instance method
     object, with 'func' being any callable object.  'func' is the
     function that will be called when the instance method is called.

 -- C Function: *note PyObject: 33a. *PyInstanceMethod_Function
          (PyObject *im)
     'Return value: Borrowed reference.'  Return the function object
     associated with the instance method 'im'.

 -- C Function: *note PyObject: 33a. *PyInstanceMethod_GET_FUNCTION
          (PyObject *im)
     'Return value: Borrowed reference.'  Macro version of *note
     PyInstanceMethod_Function(): 509a. which avoids error checking.


File: python.info,  Node: Method Objects<2>,  Next: Cell Objects,  Prev: Instance Method Objects,  Up: Function Objects<2>

7.8.5.3 Method Objects
......................

Methods are bound function objects.  Methods are always bound to an
instance of a user-defined class.  Unbound methods (methods bound to a
class object) are no longer available.

 -- C Variable: *note PyTypeObject: aba. PyMethod_Type

     This instance of *note PyTypeObject: aba. represents the Python
     method type.  This is exposed to Python programs as
     ‘types.MethodType’.

 -- C Function: int PyMethod_Check (PyObject *o)

     Return true if 'o' is a method object (has type *note
     PyMethod_Type: 509e.).  The parameter must not be ‘NULL’.  This
     function always succeeds.

 -- C Function: *note PyObject: 33a. *PyMethod_New (PyObject *func,
          PyObject *self)
     'Return value: New reference.'  Return a new method object, with
     'func' being any callable object and 'self' the instance the method
     should be bound.  'func' is the function that will be called when
     the method is called.  'self' must not be ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyMethod_Function (PyObject *meth)
     'Return value: Borrowed reference.'  Return the function object
     associated with the method 'meth'.

 -- C Function: *note PyObject: 33a. *PyMethod_GET_FUNCTION (PyObject
          *meth)
     'Return value: Borrowed reference.'  Macro version of *note
     PyMethod_Function(): 50a1. which avoids error checking.

 -- C Function: *note PyObject: 33a. *PyMethod_Self (PyObject *meth)
     'Return value: Borrowed reference.'  Return the instance associated
     with the method 'meth'.

 -- C Function: *note PyObject: 33a. *PyMethod_GET_SELF (PyObject *meth)
     'Return value: Borrowed reference.'  Macro version of *note
     PyMethod_Self(): 50a3. which avoids error checking.


File: python.info,  Node: Cell Objects,  Next: Code Objects<2>,  Prev: Method Objects<2>,  Up: Function Objects<2>

7.8.5.4 Cell Objects
....................

“Cell” objects are used to implement variables referenced by multiple
scopes.  For each such variable, a cell object is created to store the
value; the local variables of each stack frame that references the value
contain a reference to the cells from outer scopes which also use that
variable.  When the value is accessed, the value contained in the cell
is used instead of the cell object itself.  This de-referencing of the
cell object requires support from the generated byte-code; these are not
automatically de-referenced when accessed.  Cell objects are not likely
to be useful elsewhere.

 -- C Type: type PyCellObject

     The C structure used for cell objects.

 -- C Variable: *note PyTypeObject: aba. PyCell_Type

     The type object corresponding to cell objects.

 -- C Function: int PyCell_Check (PyObject *ob)

     Return true if 'ob' is a cell object; 'ob' must not be ‘NULL’.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyCell_New (PyObject *ob)
     'Return value: New reference.'  Create and return a new cell object
     containing the value 'ob'.  The parameter may be ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyCell_Get (PyObject *cell)
     'Return value: New reference.'  Return the contents of the cell
     'cell', which can be ‘NULL’.  If 'cell' is not a cell object,
     returns ‘NULL’ with an exception set.

 -- C Function: *note PyObject: 33a. *PyCell_GET (PyObject *cell)
     'Return value: Borrowed reference.'  Return the contents of the
     cell 'cell', but without checking that 'cell' is non-‘NULL’ and a
     cell object.

 -- C Function: int PyCell_Set (PyObject *cell, PyObject *value)

     Set the contents of the cell object 'cell' to 'value'.  This
     releases the reference to any current content of the cell.  'value'
     may be ‘NULL’.  'cell' must be non-‘NULL’.

     On success, return ‘0’.  If 'cell' is not a cell object, set an
     exception and return ‘-1’.

 -- C Function: void PyCell_SET (PyObject *cell, PyObject *value)

     Sets the value of the cell object 'cell' to 'value'.  No reference
     counts are adjusted, and no checks are made for safety; 'cell' must
     be non-‘NULL’ and must be a cell object.


File: python.info,  Node: Code Objects<2>,  Next: Code Object Flags,  Prev: Cell Objects,  Up: Function Objects<2>

7.8.5.5 Code Objects
....................

Code objects are a low-level detail of the CPython implementation.  Each
one represents a chunk of executable code that hasn’t yet been bound
into a function.

 -- C Type: type PyCodeObject

     The C structure of the objects used to describe code objects.  The
     fields of this type are subject to change at any time.

 -- C Variable: *note PyTypeObject: aba. PyCode_Type

     This is an instance of *note PyTypeObject: aba. representing the
     Python *note code object: 1d2.

 -- C Function: int PyCode_Check (PyObject *co)

     Return true if 'co' is a *note code object: 1d2.  This function
     always succeeds.

 -- C Function: *note Py_ssize_t: a6e. PyCode_GetNumFree (PyCodeObject
          *co)

     Return the number of *note free (closure) variables: 20f4. in a
     code object.

 -- C Function: int PyUnstable_Code_GetFirstFree (PyCodeObject *co)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return the position of the first *note free (closure) variable:
     20f4. in a code object.

     Changed in version 3.13: Renamed from ‘PyCode_GetFirstFree’ as part
     of *note Unstable C API: 54a.  The old name is deprecated, but will
     remain available until the signature changes again.

 -- C Function: *note PyCodeObject: 77a. *PyUnstable_Code_New (int
          argcount, int kwonlyargcount, int nlocals, int stacksize, int
          flags, PyObject *code, PyObject *consts, PyObject *names,
          PyObject *varnames, PyObject *freevars, PyObject *cellvars,
          PyObject *filename, PyObject *name, PyObject *qualname, int
          firstlineno, PyObject *linetable, PyObject *exceptiontable)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return a new code object.  If you need a dummy code object to
     create a frame, use *note PyCode_NewEmpty(): 139c. instead.

     Since the definition of the bytecode changes often, calling *note
     PyUnstable_Code_New(): 50b5. directly can bind you to a precise
     Python version.

     The many arguments of this function are inter-dependent in complex
     ways, meaning that subtle changes to values are likely to result in
     incorrect execution or VM crashes.  Use this function only with
     extreme care.

     Changed in version 3.11: Added ‘qualname’ and ‘exceptiontable’
     parameters.

     Changed in version 3.12: Renamed from ‘PyCode_New’ as part of *note
     Unstable C API: 54a.  The old name is deprecated, but will remain
     available until the signature changes again.

 -- C Function: *note PyCodeObject: 77a.
          *PyUnstable_Code_NewWithPosOnlyArgs (int argcount, int
          posonlyargcount, int kwonlyargcount, int nlocals, int
          stacksize, int flags, PyObject *code, PyObject *consts,
          PyObject *names, PyObject *varnames, PyObject *freevars,
          PyObject *cellvars, PyObject *filename, PyObject *name,
          PyObject *qualname, int firstlineno, PyObject *linetable,
          PyObject *exceptiontable)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Similar to *note PyUnstable_Code_New(): 50b5, but with an extra
     “posonlyargcount” for positional-only arguments.  The same caveats
     that apply to ‘PyUnstable_Code_New’ also apply to this function.

     Added in version 3.8: as ‘PyCode_NewWithPosOnlyArgs’

     Changed in version 3.11: Added ‘qualname’ and ‘exceptiontable’
     parameters.

     Changed in version 3.12: Renamed to
     ‘PyUnstable_Code_NewWithPosOnlyArgs’.  The old name is deprecated,
     but will remain available until the signature changes again.

 -- C Function: *note PyCodeObject: 77a. *PyCode_NewEmpty (const char
          *filename, const char *funcname, int firstlineno)
     'Return value: New reference.'  Return a new empty code object with
     the specified filename, function name, and first line number.  The
     resulting code object will raise an ‘Exception’ if executed.

 -- C Function: int PyCode_Addr2Line (PyCodeObject *co, int byte_offset)

     Return the line number of the instruction that occurs on or before
     ‘byte_offset’ and ends after it.  If you just need the line number
     of a frame, use *note PyFrame_GetLineNumber(): 78e. instead.

     For efficiently iterating over the line numbers in a code object,
     use the API described in PEP 626(1).

 -- C Function: int PyCode_Addr2Location (PyObject *co, int byte_offset,
          int *start_line, int *start_column, int *end_line, int
          *end_column)

     Sets the passed ‘int’ pointers to the source code line and column
     numbers for the instruction at ‘byte_offset’.  Sets the value to
     ‘0’ when information is not available for any particular element.

     Returns ‘1’ if the function succeeds and 0 otherwise.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyCode_GetCode (PyCodeObject *co)

     Equivalent to the Python code ‘getattr(co, 'co_code')’.  Returns a
     strong reference to a *note PyBytesObject: 795. representing the
     bytecode in a code object.  On error, ‘NULL’ is returned and an
     exception is raised.

     This ‘PyBytesObject’ may be created on-demand by the interpreter
     and does not necessarily represent the bytecode actually executed
     by CPython.  The primary use case for this function is debuggers
     and profilers.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyCode_GetVarnames (PyCodeObject
          *co)

     Equivalent to the Python code ‘getattr(co, 'co_varnames')’.
     Returns a new reference to a *note PyTupleObject: 4ed5. containing
     the names of the local variables.  On error, ‘NULL’ is returned and
     an exception is raised.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyCode_GetCellvars (PyCodeObject
          *co)

     Equivalent to the Python code ‘getattr(co, 'co_cellvars')’.
     Returns a new reference to a *note PyTupleObject: 4ed5. containing
     the names of the local variables that are referenced by nested
     functions.  On error, ‘NULL’ is returned and an exception is
     raised.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyCode_GetFreevars (PyCodeObject
          *co)

     Equivalent to the Python code ‘getattr(co, 'co_freevars')’.
     Returns a new reference to a *note PyTupleObject: 4ed5. containing
     the names of the *note free (closure) variables: 20f4.  On error,
     ‘NULL’ is returned and an exception is raised.

     Added in version 3.11.

 -- C Function: int PyCode_AddWatcher (PyCode_WatchCallback callback)

     Register 'callback' as a code object watcher for the current
     interpreter.  Return an ID which may be passed to *note
     PyCode_ClearWatcher(): 56a.  In case of error (e.g.  no more
     watcher IDs available), return ‘-1’ and set an exception.

     Added in version 3.12.

 -- C Function: int PyCode_ClearWatcher (int watcher_id)

     Clear watcher identified by 'watcher_id' previously returned from
     *note PyCode_AddWatcher(): 569. for the current interpreter.
     Return ‘0’ on success, or ‘-1’ and set an exception on error (e.g.
     if the given 'watcher_id' was never registered.)

     Added in version 3.12.

 -- C Type: type PyCodeEvent

     Enumeration of possible code object watcher events: -
     ‘PY_CODE_EVENT_CREATE’ - ‘PY_CODE_EVENT_DESTROY’

     Added in version 3.12.

 -- C Type: typedef int (*PyCode_WatchCallback)(*note PyCodeEvent: 50b8.
          event, *note PyCodeObject: 77a. *co)

     Type of a code object watcher callback function.

     If 'event' is ‘PY_CODE_EVENT_CREATE’, then the callback is invoked
     after 'co' has been fully initialized.  Otherwise, the callback is
     invoked before the destruction of 'co' takes place, so the prior
     state of 'co' can be inspected.

     If 'event' is ‘PY_CODE_EVENT_DESTROY’, taking a reference in the
     callback to the about-to-be-destroyed code object will resurrect it
     and prevent it from being freed at this time.  When the resurrected
     object is destroyed later, any watcher callbacks active at that
     time will be called again.

     Users of this API should not rely on internal runtime
     implementation details.  Such details may include, but are not
     limited to, the exact order and timing of creation and destruction
     of code objects.  While changes in these details may result in
     differences observable by watchers (including whether a callback is
     invoked or not), it does not change the semantics of the Python
     code being executed.

     If the callback sets an exception, it must return ‘-1’; this
     exception will be printed as an unraisable exception using *note
     PyErr_WriteUnraisable(): 350.  Otherwise it should return ‘0’.

     There may already be a pending exception set on entry to the
     callback.  In this case, the callback should return ‘0’ with the
     same exception still set.  This means the callback may not call any
     other API that can set an exception unless it saves and clears the
     exception state first, and restores it before returning.

     Added in version 3.12.

 -- C Function: *note PyObject: 33a. *PyCode_Optimize (PyObject *code,
          PyObject *consts, PyObject *names, PyObject *lnotab_obj)

     This is a *note soft deprecated: 209. function that does nothing.

     Prior to Python 3.10, this function would perform basic
     optimizations to a code object.

     Changed in version 3.10: This function now does nothing.

   ---------- Footnotes ----------

   (1) 
https://peps.python.org/pep-0626/#out-of-process-debuggers-and-profilers


File: python.info,  Node: Code Object Flags,  Next: Extra information,  Prev: Code Objects<2>,  Up: Function Objects<2>

7.8.5.6 Code Object Flags
.........................

Code objects contain a bit-field of flags, which can be retrieved as the
*note co_flags: 20f9. Python attribute (for example using *note
PyObject_GetAttrString(): 34d.), and set using a 'flags' argument to
*note PyUnstable_Code_New(): 50b5. and similar functions.

Flags whose names start with ‘CO_FUTURE_’ correspond to features
normally selectable by *note future statements: 189.  These flags can be
used in *note PyCompilerFlags.cf_flags: 4e98.  Note that many
‘CO_FUTURE_’ flags are mandatory in current versions of Python, and
setting them has no effect.

The following flags are available.  For their meaning, see the linked
documentation of their Python equivalents.

Flag                                                   Meaning
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Macro: CO_OPTIMIZED                              *note inspect.CO_OPTIMIZED: 471c.
                                                       
                                                       
 -- C Macro: CO_NEWLOCALS                              *note inspect.CO_NEWLOCALS: 471d.
                                                       
                                                       
 -- C Macro: CO_VARARGS                                *note inspect.CO_VARARGS: 471e.
                                                       
                                                       
 -- C Macro: CO_VARKEYWORDS                            *note inspect.CO_VARKEYWORDS: 471f.
                                                       
                                                       
 -- C Macro: CO_NESTED                                 *note inspect.CO_NESTED: 4720.
                                                       
                                                       
 -- C Macro: CO_GENERATOR                              *note inspect.CO_GENERATOR: 4721.
                                                       
                                                       
 -- C Macro: CO_COROUTINE                              *note inspect.CO_COROUTINE: 4722.
                                                       
                                                       
 -- C Macro: CO_ITERABLE_COROUTINE                     *note inspect.CO_ITERABLE_COROUTINE: 4723.
                                                       
                                                       
 -- C Macro: CO_ASYNC_GENERATOR                        *note inspect.CO_ASYNC_GENERATOR: 4724.
                                                       
                                                       
 -- C Macro: CO_FUTURE_DIVISION                        no effect (*note __future__.division: 46c5.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_ABSOLUTE_IMPORT                 no effect (*note __future__.absolute_import: 46c6.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_WITH_STATEMENT                  no effect (*note __future__.with_statement: 46c7.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_PRINT_FUNCTION                  no effect (*note __future__.print_function: 46c8.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_UNICODE_LITERALS                no effect (*note __future__.unicode_literals: 46c9.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_GENERATOR_STOP                  no effect (*note __future__.generator_stop: 46ca.)
                                                       
                                                       
 -- C Macro: CO_FUTURE_ANNOTATIONS                     *note __future__.annotations: 46cb.
                                                       


File: python.info,  Node: Extra information,  Prev: Code Object Flags,  Up: Function Objects<2>

7.8.5.7 Extra information
.........................

To support low-level extensions to frame evaluation, such as external
just-in-time compilers, it is possible to attach arbitrary extra data to
code objects.

These functions are part of the unstable C API tier: this functionality
is a CPython implementation detail, and the API may change without
deprecation warnings.

 -- C Function: *note Py_ssize_t: a6e.
          PyUnstable_Eval_RequestCodeExtraIndex (freefunc free)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return a new opaque index value used to adding data to code
     objects.

     You generally call this function once (per interpreter) and use the
     result with ‘PyCode_GetExtra’ and ‘PyCode_SetExtra’ to manipulate
     data on individual code objects.

     If 'free' is not ‘NULL’: when a code object is deallocated, 'free'
     will be called on non-‘NULL’ data stored under the new index.  Use
     *note Py_DecRef(): 4dea. when storing *note PyObject: 33a.

     Added in version 3.6: as ‘_PyEval_RequestCodeExtraIndex’

     Changed in version 3.12: Renamed to
     ‘PyUnstable_Eval_RequestCodeExtraIndex’.  The old private name is
     deprecated, but will be available until the API changes.

 -- C Function: int PyUnstable_Code_GetExtra (PyObject *code, Py_ssize_t
          index, void **extra)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Set 'extra' to the extra data stored under the given index.  Return
     0 on success.  Set an exception and return -1 on failure.

     If no data was set under the index, set 'extra' to ‘NULL’ and
     return 0 without setting an exception.

     Added in version 3.6: as ‘_PyCode_GetExtra’

     Changed in version 3.12: Renamed to ‘PyUnstable_Code_GetExtra’.
     The old private name is deprecated, but will be available until the
     API changes.

 -- C Function: int PyUnstable_Code_SetExtra (PyObject *code, Py_ssize_t
          index, void *extra)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Set the extra data stored under the given index to 'extra'.  Return
     0 on success.  Set an exception and return -1 on failure.

     Added in version 3.6: as ‘_PyCode_SetExtra’

     Changed in version 3.12: Renamed to ‘PyUnstable_Code_SetExtra’.
     The old private name is deprecated, but will be available until the
     API changes.


File: python.info,  Node: Other Objects,  Next: C API for extension modules,  Prev: Function Objects<2>,  Up: Concrete Objects Layer

7.8.6 Other Objects
-------------------

* Menu:

* File Objects::
* Module Objects::
* Iterator Objects::
* Descriptor Objects::
* Slice Objects::
* MemoryView objects::
* Pickle buffer objects::
* Weak Reference Objects: Weak Reference Objects<2>.
* Capsules: Capsules<2>.
* Frame Objects::
* Generator Objects::
* Coroutine Objects: Coroutine Objects<2>.
* Context Variables Objects::
* Objects for Type Hinting::


File: python.info,  Node: File Objects,  Next: Module Objects,  Up: Other Objects

7.8.6.1 File Objects
....................

These APIs are a minimal emulation of the Python 2 C API for built-in
file objects, which used to rely on the buffered I/O (FILE*) support
from the C standard library.  In Python 3, files and streams use the new
*note io: 7f. module, which defines several layers over the low-level
unbuffered I/O of the operating system.  The functions described below
are convenience C wrappers over these new APIs, and meant mostly for
internal error reporting in the interpreter; third-party code is advised
to access the ‘io’ APIs instead.

 -- C Function: *note PyObject: 33a. *PyFile_FromFd (int fd, const char
          *name, const char *mode, int buffering, const char *encoding,
          const char *errors, const char *newline, int closefd)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a Python file object from the file descriptor of an
     already opened file 'fd'.  The arguments 'name', 'encoding',
     'errors' and 'newline' can be ‘NULL’ to use the defaults;
     'buffering' can be '-1' to use the default.  'name' is ignored and
     kept for backward compatibility.  Return ‘NULL’ on failure.  For a
     more comprehensive description of the arguments, please refer to
     the *note io.open(): 520. function documentation.

          Warning: Since Python streams have their own buffering layer,
          mixing them with OS-level file descriptors can produce various
          issues (such as unexpected ordering of data).

     Changed in version 3.2: Ignore 'name' attribute.

 -- C Function: int PyObject_AsFileDescriptor (PyObject *p)
     ' Part of the *note Stable ABI: 556.'  Return the file descriptor
     associated with 'p' as an int.  If the object is an integer, its
     value is returned.  If not, the object’s *note fileno(): 15f5.
     method is called if it exists; the method must return an integer,
     which is returned as the file descriptor value.  Sets an exception
     and returns ‘-1’ on failure.

 -- C Function: *note PyObject: 33a. *PyFile_GetLine (PyObject *p, int
          n)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Equivalent to ‘p.readline([n])’, this function reads one line from
     the object 'p'.  'p' may be a file object or any object with a
     *note readline(): 1373. method.  If 'n' is ‘0’, exactly one line is
     read, regardless of the length of the line.  If 'n' is greater than
     ‘0’, no more than 'n' bytes will be read from the file; a partial
     line can be returned.  In both cases, an empty string is returned
     if the end of the file is reached immediately.  If 'n' is less than
     ‘0’, however, one line is read regardless of length, but *note
     EOFError: 1321. is raised if the end of the file is reached
     immediately.

 -- C Function: int PyFile_SetOpenCodeHook (Py_OpenCodeHookFunction
          handler)

     Overrides the normal behavior of *note io.open_code(): 15a7. to
     pass its parameter through the provided handler.

     The 'handler' is a function of type:

      -- C Type: typedef *note PyObject: 33a.
               *(*Py_OpenCodeHookFunction)(*note PyObject: 33a.*, void*)

          Equivalent of *note PyObject: 33a. *(*)(PyObject *path, void
          *userData), where 'path' is guaranteed to be *note
          PyUnicodeObject: 797.

     The 'userData' pointer is passed into the hook function.  Since
     hook functions may be called from different runtimes, this pointer
     should not refer directly to Python state.

     As this hook is intentionally used during import, avoid importing
     new modules during its execution unless they are known to be frozen
     or available in ‘sys.modules’.

     Once a hook has been set, it cannot be removed or replaced, and
     later calls to *note PyFile_SetOpenCodeHook(): 183a. will fail.  On
     failure, the function returns -1 and sets an exception if the
     interpreter has been initialized.

     This function is safe to call before *note Py_Initialize(): 8b4.

     Raises an *note auditing event: 1a15. ‘setopencodehook’ with no
     arguments.

     Added in version 3.8.

 -- C Function: *note PyObject: 33a. *PyFile_OpenCodeObject (PyObject
          *path)

     Open 'path' with the mode ‘'rb'’.  'path' must be a Python *note
     str: 44f. object.  The behavior of this function may be overridden
     by *note PyFile_SetOpenCodeHook(): 183a. to allow for some
     preprocessing of the text.

     This is analogous to *note io.open_code(): 15a7. in Python.

     On success, this function returns a *note strong reference: 33e. to
     a Python file object.  On failure, this function returns ‘NULL’
     with an exception set.

     Added in version 3.8.

 -- C Function: *note PyObject: 33a. *PyFile_OpenCode (const char *path)

     Similar to *note PyFile_OpenCodeObject(): 50d7, but 'path' is a
     UTF-8 encoded const char*.

     Added in version 3.8.

 -- C Function: int PyFile_WriteObject (PyObject *obj, PyObject *p, int
          flags)
     ' Part of the *note Stable ABI: 556.'

     Write object 'obj' to file object 'p'.  The only supported flag for
     'flags' is *note Py_PRINT_RAW: 4f38.; if given, the *note str():
     44f. of the object is written instead of the *note repr(): 803.

     If 'obj' is ‘NULL’, write the string ‘"<NULL>"’.

     Return ‘0’ on success or ‘-1’ on failure; the appropriate exception
     will be set.

 -- C Function: int PyFile_WriteString (const char *s, PyObject *p)
     ' Part of the *note Stable ABI: 556.'  Write string 's' to file
     object 'p'.  Return ‘0’ on success or ‘-1’ on failure; the
     appropriate exception will be set.


File: python.info,  Node: Module Objects,  Next: Iterator Objects,  Prev: File Objects,  Up: Other Objects

7.8.6.2 Module Objects
......................

 -- C Variable: *note PyTypeObject: aba. PyModule_Type
     ' Part of the *note Stable ABI: 556.'

     This instance of *note PyTypeObject: aba. represents the Python
     module type.  This is exposed to Python programs as *note
     types.ModuleType: e45.

 -- C Function: int PyModule_Check (PyObject *p)

     Return true if 'p' is a module object, or a subtype of a module
     object.  This function always succeeds.

 -- C Function: int PyModule_CheckExact (PyObject *p)

     Return true if 'p' is a module object, but not a subtype of *note
     PyModule_Type: 4d29.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyModule_NewObject (PyObject
          *name)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'

     Return a new module object with *note module.__name__: 13d8. set to
     'name'.  The module’s ‘__name__’, *note __doc__: 1993, *note
     __package__: 2d7. and *note __loader__: 2e2. attributes are filled
     in (all but ‘__name__’ are set to ‘None’).  The caller is
     responsible for setting a *note __file__: 20cc. attribute.

     Return ‘NULL’ with an exception set on error.

     Added in version 3.3.

     Changed in version 3.4: *note __package__: 2d7. and *note
     __loader__: 2e2. are now set to ‘None’.

 -- C Function: *note PyObject: 33a. *PyModule_New (const char *name)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Similar to *note PyModule_NewObject(): 4d27, but the name is
     a UTF-8 encoded string instead of a Unicode object.

 -- C Function: *note PyObject: 33a. *PyModule_GetDict (PyObject
          *module)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'

     Return the dictionary object that implements 'module'’s namespace;
     this object is the same as the *note __dict__: 55e. attribute of
     the module object.  If 'module' is not a module object (or a
     subtype of a module object), *note SystemError: 578. is raised and
     ‘NULL’ is returned.

     It is recommended extensions use other ‘PyModule_*’ and
     ‘PyObject_*’ functions rather than directly manipulate a module’s
     *note __dict__: 55e.

     The returned reference is borrowed from the module; it is valid
     until the module is destroyed.

 -- C Function: *note PyObject: 33a. *PyModule_GetNameObject (PyObject
          *module)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'

     Return 'module'’s *note __name__: 13d8. value.  If the module does
     not provide one, or if it is not a string, *note SystemError: 578.
     is raised and ‘NULL’ is returned.

     Added in version 3.3.

 -- C Function: const char *PyModule_GetName (PyObject *module)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyModule_GetNameObject(): 4d25. but return the name encoded to
     ‘'utf-8'’.

     The returned buffer is only valid until the module is renamed or
     destroyed.  Note that Python code may rename a module by setting
     its *note __name__: 13d8. attribute.

 -- C Function: void *PyModule_GetState (PyObject *module)
     ' Part of the *note Stable ABI: 556.'  Return the “state” of the
     module, that is, a pointer to the block of memory allocated at
     module creation time, or ‘NULL’.  See *note PyModuleDef.m_size:
     989.

 -- C Function: *note PyModuleDef: 987. *PyModule_GetDef (PyObject
          *module)
     ' Part of the *note Stable ABI: 556.'  Return a pointer to the
     *note PyModuleDef: 987. struct from which the module was created,
     or ‘NULL’ if the module wasn’t created from a definition.

     On error, return ‘NULL’ with an exception set.  Use *note
     PyErr_Occurred(): 1a55. to tell this case apart from a missing
     ‘PyModuleDef’.

 -- C Function: *note PyObject: 33a. *PyModule_GetFilenameObject
          (PyObject *module)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

     Return the name of the file from which 'module' was loaded using
     'module'’s *note __file__: 20cc. attribute.  If this is not
     defined, or if it is not a string, raise *note SystemError: 578.
     and return ‘NULL’; otherwise return a reference to a Unicode
     object.

     Added in version 3.2.

 -- C Function: const char *PyModule_GetFilename (PyObject *module)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyModule_GetFilenameObject(): 3fc. but return the filename encoded
     to ‘utf-8’.

     The returned buffer is only valid until the module’s *note
     __file__: 20cc. attribute is reassigned or the module is destroyed.

     Deprecated since version 3.2: *note PyModule_GetFilename(): 3fb.
     raises *note UnicodeEncodeError: 67a. on unencodable filenames, use
     *note PyModule_GetFilenameObject(): 3fc. instead.

* Menu:

* Initializing C modules::
* Module lookup::


File: python.info,  Node: Initializing C modules,  Next: Module lookup,  Up: Module Objects

7.8.6.3 Initializing C modules
..............................

Modules objects are usually created from extension modules (shared
libraries which export an initialization function), or compiled-in
modules (where the initialization function is added using *note
PyImport_AppendInittab(): 18bf.).  See *note Building C and C++
Extensions: 4b72. or *note Extending Embedded Python: 4be0. for details.

The initialization function can either pass a module definition instance
to *note PyModule_Create(): 50e0, and return the resulting module
object, or request “multi-phase initialization” by returning the
definition struct itself.

 -- C Type: type PyModuleDef
     ' Part of the *note Stable ABI: 556. (including all members).'  The
     module definition struct, which holds all information needed to
     create a module object.  There is usually only one statically
     initialized variable of this type for each module.

      -- C Member: PyModuleDef_Base m_base

          Always initialize this member to ‘PyModuleDef_HEAD_INIT’.

      -- C Member: const char *m_name

          Name for the new module.

      -- C Member: const char *m_doc

          Docstring for the module; usually a docstring variable created
          with *note PyDoc_STRVAR: 1b04. is used.

      -- C Member: *note Py_ssize_t: a6e. m_size

          Module state may be kept in a per-module memory area that can
          be retrieved with *note PyModule_GetState(): 98a, rather than
          in static globals.  This makes modules safe for use in
          multiple sub-interpreters.

          This memory area is allocated based on 'm_size' on module
          creation, and freed when the module object is deallocated,
          after the *note m_free: 986. function has been called, if
          present.

          Setting ‘m_size’ to ‘-1’ means that the module does not
          support sub-interpreters, because it has global state.

          Setting it to a non-negative value means that the module can
          be re-initialized and specifies the additional amount of
          memory it requires for its state.  Non-negative ‘m_size’ is
          required for multi-phase initialization.

          See PEP 3121(1) for more details.

      -- C Member: *note PyMethodDef: 1526. *m_methods

          A pointer to a table of module-level functions, described by
          *note PyMethodDef: 1526. values.  Can be ‘NULL’ if no
          functions are present.

      -- C Member: *note PyModuleDef_Slot: 4d1e. *m_slots

          An array of slot definitions for multi-phase initialization,
          terminated by a ‘{0, NULL}’ entry.  When using single-phase
          initialization, 'm_slots' must be ‘NULL’.

          Changed in version 3.5: Prior to version 3.5, this member was
          always set to ‘NULL’, and was defined as:

                -- C Member: *note inquiry: 4e69. m_reload

      -- C Member: *note traverseproc: 4e78. m_traverse

          A traversal function to call during GC traversal of the module
          object, or ‘NULL’ if not needed.

          This function is not called if the module state was requested
          but is not allocated yet.  This is the case immediately after
          the module is created and before the module is executed (*note
          Py_mod_exec: 988. function).  More precisely, this function is
          not called if *note m_size: 989. is greater than 0 and the
          module state (as returned by *note PyModule_GetState(): 98a.)
          is ‘NULL’.

          Changed in version 3.9: No longer called before the module
          state is allocated.

      -- C Member: *note inquiry: 4e69. m_clear

          A clear function to call during GC clearing of the module
          object, or ‘NULL’ if not needed.

          This function is not called if the module state was requested
          but is not allocated yet.  This is the case immediately after
          the module is created and before the module is executed (*note
          Py_mod_exec: 988. function).  More precisely, this function is
          not called if *note m_size: 989. is greater than 0 and the
          module state (as returned by *note PyModule_GetState(): 98a.)
          is ‘NULL’.

          Like *note PyTypeObject.tp_clear: 4bac, this function is not
          'always' called before a module is deallocated.  For example,
          when reference counting is enough to determine that an object
          is no longer used, the cyclic garbage collector is not
          involved and *note m_free: 986. is called directly.

          Changed in version 3.9: No longer called before the module
          state is allocated.

      -- C Member: *note freefunc: 50e7. m_free

          A function to call during deallocation of the module object,
          or ‘NULL’ if not needed.

          This function is not called if the module state was requested
          but is not allocated yet.  This is the case immediately after
          the module is created and before the module is executed (*note
          Py_mod_exec: 988. function).  More precisely, this function is
          not called if *note m_size: 989. is greater than 0 and the
          module state (as returned by *note PyModule_GetState(): 98a.)
          is ‘NULL’.

          Changed in version 3.9: No longer called before the module
          state is allocated.

 -- C Variable: *note PyTypeObject: aba. PyModuleDef_Type
     ' Part of the *note Stable ABI: 556. since version 3.5.'  The type
     of ‘PyModuleDef’ objects.

* Menu:

* Single-phase initialization::
* Multi-phase initialization::
* Low-level module creation functions::
* Support functions::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3121/


File: python.info,  Node: Single-phase initialization,  Next: Multi-phase initialization,  Up: Initializing C modules

7.8.6.4 Single-phase initialization
...................................

The module initialization function may create and return the module
object directly.  This is referred to as “single-phase initialization”,
and uses one of the following two module creation functions:

 -- C Function: *note PyObject: 33a. *PyModule_Create (PyModuleDef *def)
     'Return value: New reference.'  Create a new module object, given
     the definition in 'def'.  This behaves like *note
     PyModule_Create2(): 4d21. with 'module_api_version' set to
     ‘PYTHON_API_VERSION’.

 -- C Function: *note PyObject: 33a. *PyModule_Create2 (PyModuleDef
          *def, int module_api_version)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a new module object, given the definition in 'def',
     assuming the API version 'module_api_version'.  If that version
     does not match the version of the running interpreter, a *note
     RuntimeWarning: 1bd. is emitted.

     Return ‘NULL’ with an exception set on error.

          Note: Most uses of this function should be using *note
          PyModule_Create(): 50e0. instead; only use this if you are
          sure you need it.

Before it is returned from in the initialization function, the resulting
module object is typically populated using functions like *note
PyModule_AddObjectRef(): 368.


File: python.info,  Node: Multi-phase initialization,  Next: Low-level module creation functions,  Prev: Single-phase initialization,  Up: Initializing C modules

7.8.6.5 Multi-phase initialization
..................................

An alternate way to specify extensions is to request “multi-phase
initialization”.  Extension modules created this way behave more like
Python modules: the initialization is split between the 'creation
phase', when the module object is created, and the 'execution phase',
when it is populated.  The distinction is similar to the *note
__new__(): 583. and *note __init__(): 6b3. methods of classes.

Unlike modules created using single-phase initialization, these modules
are not singletons.  For example, if the *note sys.modules: 1655. entry
is removed and the module is re-imported, a new module object is
created, and typically populated with fresh method and type objects.
The old module is subject to normal garbage collection.  This mirrors
the behavior of pure-Python modules.

Additional module instances may be created in *note sub-interpreters:
58a. or after after Python runtime reinitialization (*note
Py_Finalize(): 13a6. and *note Py_Initialize(): 8b4.).  In these cases,
sharing Python objects between module instances would likely cause
crashes or undefined behavior.

To avoid such issues, each instance of an extension module should be
'isolated': changes to one instance should not implicitly affect the
others, and all state, including references to Python objects, should be
specific to a particular module instance.  See *note Isolating Extension
Modules: 4b6e. for more details and a practical guide.

A simpler way to avoid these issues is *note raising an error on
repeated initialization: 50ea.

All modules created using multi-phase initialization are expected to
support *note sub-interpreters: 58a, or otherwise explicitly signal a
lack of support.  This is usually achieved by isolation or blocking
repeated initialization, as above.  A module may also be limited to the
main interpreter using the *note Py_mod_multiple_interpreters: 4e11.
slot.

To request multi-phase initialization, the initialization function
(PyInit_modulename) returns a *note PyModuleDef: 987. instance with
non-empty *note m_slots: 50e5.  Before it is returned, the ‘PyModuleDef’
instance must be initialized with the following function:

 -- C Function: *note PyObject: 33a. *PyModuleDef_Init (PyModuleDef
          *def)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.5.'  Ensures a module definition is a properly
     initialized Python object that correctly reports its type and
     reference count.

     Returns 'def' cast to ‘PyObject*’, or ‘NULL’ if an error occurred.

     Added in version 3.5.

The 'm_slots' member of the module definition must point to an array of
‘PyModuleDef_Slot’ structures:

 -- C Type: type PyModuleDef_Slot
     ' Part of the *note Stable ABI: 556. (including all members) since
     version 3.5.'
      -- C Member: int slot

          A slot ID, chosen from the available values explained below.

      -- C Member: void *value

          Value of the slot, whose meaning depends on the slot ID.

     Added in version 3.5.

The 'm_slots' array must be terminated by a slot with id 0.

The available slot types are:

 -- C Macro: Py_mod_create
     ' Part of the *note Stable ABI: 556. since version 3.5.'  Specifies
     a function that is called to create the module object itself.  The
     'value' pointer of this slot must point to a function of the
     signature:

      -- C Function: *note PyObject: 33a. *create_module (PyObject
               *spec, PyModuleDef *def)

     The function receives a *note ModuleSpec: 200d. instance, as
     defined in PEP 451(1), and the module definition.  It should return
     a new module object, or set an error and return ‘NULL’.

     This function should be kept minimal.  In particular, it should not
     call arbitrary Python code, as trying to import the same module
     again may result in an infinite loop.

     Multiple ‘Py_mod_create’ slots may not be specified in one module
     definition.

     If ‘Py_mod_create’ is not specified, the import machinery will
     create a normal module object using *note PyModule_New(): 4d26.
     The name is taken from 'spec', not the definition, to allow
     extension modules to dynamically adjust to their place in the
     module hierarchy and be imported under different names through
     symlinks, all while sharing a single module definition.

     There is no requirement for the returned object to be an instance
     of *note PyModule_Type: 4d29.  Any type can be used, as long as it
     supports setting and getting import-related attributes.  However,
     only ‘PyModule_Type’ instances may be returned if the ‘PyModuleDef’
     has non-‘NULL’ ‘m_traverse’, ‘m_clear’, ‘m_free’; non-zero
     ‘m_size’; or slots other than ‘Py_mod_create’.

     Added in version 3.5.

 -- C Macro: Py_mod_exec
     ' Part of the *note Stable ABI: 556. since version 3.5.'  Specifies
     a function that is called to 'execute' the module.  This is
     equivalent to executing the code of a Python module: typically,
     this function adds classes and constants to the module.  The
     signature of the function is:

      -- C Function: int exec_module (PyObject *module)

     If multiple ‘Py_mod_exec’ slots are specified, they are processed
     in the order they appear in the 'm_slots' array.

     Added in version 3.5.

 -- C Macro: Py_mod_multiple_interpreters
     ' Part of the *note Stable ABI: 556. since version 3.12.'
     Specifies one of the following values:

      -- C Macro: Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED

          The module does not support being imported in subinterpreters.

      -- C Macro: Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED

          The module supports being imported in subinterpreters, but
          only when they share the main interpreter’s GIL. (See *note
          Isolating Extension Modules: 4b6e.)

      -- C Macro: Py_MOD_PER_INTERPRETER_GIL_SUPPORTED

          The module supports being imported in subinterpreters, even
          when they have their own GIL. (See *note Isolating Extension
          Modules: 4b6e.)

     This slot determines whether or not importing this module in a
     subinterpreter will fail.

     Multiple ‘Py_mod_multiple_interpreters’ slots may not be specified
     in one module definition.

     If ‘Py_mod_multiple_interpreters’ is not specified, the import
     machinery defaults to ‘Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED’.

     Added in version 3.12.

 -- C Macro: Py_mod_gil
     ' Part of the *note Stable ABI: 556. since version 3.13.'
     Specifies one of the following values:

      -- C Macro: Py_MOD_GIL_USED

          The module depends on the presence of the global interpreter
          lock (GIL), and may access global state without
          synchronization.

      -- C Macro: Py_MOD_GIL_NOT_USED

          The module is safe to run without an active GIL.

     This slot is ignored by Python builds not configured with *note
     -disable-gil: 174.  Otherwise, it determines whether or not
     importing this module will cause the GIL to be automatically
     enabled.  See *note Free-threaded CPython: 13f. for more detail.

     Multiple ‘Py_mod_gil’ slots may not be specified in one module
     definition.

     If ‘Py_mod_gil’ is not specified, the import machinery defaults to
     ‘Py_MOD_GIL_USED’.

     Added in version 3.13.

See PEP 489(2) for more details on multi-phase initialization.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0451/

   (2) https://peps.python.org/pep-0489/


File: python.info,  Node: Low-level module creation functions,  Next: Support functions,  Prev: Multi-phase initialization,  Up: Initializing C modules

7.8.6.6 Low-level module creation functions
...........................................

The following functions are called under the hood when using multi-phase
initialization.  They can be used directly, for example when creating
module objects dynamically.  Note that both ‘PyModule_FromDefAndSpec’
and ‘PyModule_ExecDef’ must be called to fully initialize a module.

 -- C Function: *note PyObject: 33a. *PyModule_FromDefAndSpec
          (PyModuleDef *def, PyObject *spec)
     'Return value: New reference.'  Create a new module object, given
     the definition in 'def' and the ModuleSpec 'spec'.  This behaves
     like *note PyModule_FromDefAndSpec2(): ee8. with
     'module_api_version' set to ‘PYTHON_API_VERSION’.

     Added in version 3.5.

 -- C Function: *note PyObject: 33a. *PyModule_FromDefAndSpec2
          (PyModuleDef *def, PyObject *spec, int module_api_version)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Create a new module object, given the
     definition in 'def' and the ModuleSpec 'spec', assuming the API
     version 'module_api_version'.  If that version does not match the
     version of the running interpreter, a *note RuntimeWarning: 1bd. is
     emitted.

     Return ‘NULL’ with an exception set on error.

          Note: Most uses of this function should be using *note
          PyModule_FromDefAndSpec(): ee7. instead; only use this if you
          are sure you need it.

     Added in version 3.5.

 -- C Function: int PyModule_ExecDef (PyObject *module, PyModuleDef
          *def)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Process
     any execution slots (*note Py_mod_exec: 988.) given in 'def'.

     Added in version 3.5.

 -- C Function: int PyModule_SetDocString (PyObject *module, const char
          *docstring)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Set the
     docstring for 'module' to 'docstring'.  This function is called
     automatically when creating a module from ‘PyModuleDef’, using
     either ‘PyModule_Create’ or ‘PyModule_FromDefAndSpec’.

     Return ‘0’ on success.  Return ‘-1’ with an exception set on error.

     Added in version 3.5.

 -- C Function: int PyModule_AddFunctions (PyObject *module, PyMethodDef
          *functions)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Add the
     functions from the ‘NULL’ terminated 'functions' array to 'module'.
     Refer to the *note PyMethodDef: 1526. documentation for details on
     individual entries (due to the lack of a shared module namespace,
     module level “functions” implemented in C typically receive the
     module as their first parameter, making them similar to instance
     methods on Python classes).  This function is called automatically
     when creating a module from ‘PyModuleDef’, using either
     ‘PyModule_Create’ or ‘PyModule_FromDefAndSpec’.

     The 'functions' array must be statically allocated (or otherwise
     guaranteed to outlive the module object).

     Added in version 3.5.


File: python.info,  Node: Support functions,  Prev: Low-level module creation functions,  Up: Initializing C modules

7.8.6.7 Support functions
.........................

The module initialization function (if using single phase
initialization) or a function called from a module execution slot (if
using multi-phase initialization), can use the following functions to
help initialize the module state:

 -- C Function: int PyModule_AddObjectRef (PyObject *module, const char
          *name, PyObject *value)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Add an
     object to 'module' as 'name'.  This is a convenience function which
     can be used from the module’s initialization function.

     On success, return ‘0’.  On error, raise an exception and return
     ‘-1’.

     Example usage:

          static int
          add_spam(PyObject *module, int value)
          {
              PyObject *obj = PyLong_FromLong(value);
              if (obj == NULL) {
                  return -1;
              }
              int res = PyModule_AddObjectRef(module, "spam", obj);
              Py_DECREF(obj);
              return res;
           }

     To be convenient, the function accepts ‘NULL’ 'value' with an
     exception set.  In this case, return ‘-1’ and just leave the raised
     exception unchanged.

     The example can also be written without checking explicitly if
     'obj' is ‘NULL’:

          static int
          add_spam(PyObject *module, int value)
          {
              PyObject *obj = PyLong_FromLong(value);
              int res = PyModule_AddObjectRef(module, "spam", obj);
              Py_XDECREF(obj);
              return res;
           }

     Note that ‘Py_XDECREF()’ should be used instead of ‘Py_DECREF()’ in
     this case, since 'obj' can be ‘NULL’.

     The number of different 'name' strings passed to this function
     should be kept small, usually by only using statically allocated
     strings as 'name'.  For names that aren’t known at compile time,
     prefer calling *note PyUnicode_FromString(): 4dda. and *note
     PyObject_SetAttr(): 4d5d. directly.  For more details, see *note
     PyUnicode_InternFromString(): 1708, which may be used internally to
     create a key object.

     Added in version 3.10.

 -- C Function: int PyModule_Add (PyObject *module, const char *name,
          PyObject *value)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Similar
     to *note PyModule_AddObjectRef(): 368, but “steals” a reference to
     'value'.  It can be called with a result of function that returns a
     new reference without bothering to check its result or even saving
     it to a variable.

     Example usage:

          if (PyModule_Add(module, "spam", PyBytes_FromString(value)) < 0) {
              goto error;
          }

     Added in version 3.13.

 -- C Function: int PyModule_AddObject (PyObject *module, const char
          *name, PyObject *value)
     ' Part of the *note Stable ABI: 556.'  Similar to *note
     PyModule_AddObjectRef(): 368, but steals a reference to 'value' on
     success (if it returns ‘0’).

     The new *note PyModule_Add(): 367. or *note
     PyModule_AddObjectRef(): 368. functions are recommended, since it
     is easy to introduce reference leaks by misusing the *note
     PyModule_AddObject(): 369. function.

          Note: Unlike other functions that steal references,
          ‘PyModule_AddObject()’ only releases the reference to 'value'
          'on success'.

          This means that its return value must be checked, and calling
          code must *note Py_XDECREF(): 792. 'value' manually on error.

     Example usage:

          PyObject *obj = PyBytes_FromString(value);
          if (PyModule_AddObject(module, "spam", obj) < 0) {
              // If 'obj' is not NULL and PyModule_AddObject() failed,
              // 'obj' strong reference must be deleted with Py_XDECREF().
              // If 'obj' is NULL, Py_XDECREF() does nothing.
              Py_XDECREF(obj);
              goto error;
          }
          // PyModule_AddObject() stole a reference to obj:
          // Py_XDECREF(obj) is not needed here.

     Deprecated since version 3.13: *note PyModule_AddObject(): 369. is
     *note soft deprecated: 209.

 -- C Function: int PyModule_AddIntConstant (PyObject *module, const
          char *name, long value)
     ' Part of the *note Stable ABI: 556.'  Add an integer constant to
     'module' as 'name'.  This convenience function can be used from the
     module’s initialization function.  Return ‘-1’ with an exception
     set on error, ‘0’ on success.

     This is a convenience function that calls *note PyLong_FromLong():
     1975. and *note PyModule_AddObjectRef(): 368.; see their
     documentation for details.

 -- C Function: int PyModule_AddStringConstant (PyObject *module, const
          char *name, const char *value)
     ' Part of the *note Stable ABI: 556.'  Add a string constant to
     'module' as 'name'.  This convenience function can be used from the
     module’s initialization function.  The string 'value' must be
     ‘NULL’-terminated.  Return ‘-1’ with an exception set on error, ‘0’
     on success.

     This is a convenience function that calls *note
     PyUnicode_InternFromString(): 1708. and *note
     PyModule_AddObjectRef(): 368.; see their documentation for details.

 -- C Macro: PyModule_AddIntMacro (module, macro)

     Add an int constant to 'module'.  The name and the value are taken
     from 'macro'.  For example ‘PyModule_AddIntMacro(module, AF_INET)’
     adds the int constant 'AF_INET' with the value of 'AF_INET' to
     'module'.  Return ‘-1’ with an exception set on error, ‘0’ on
     success.

 -- C Macro: PyModule_AddStringMacro (module, macro)

     Add a string constant to 'module'.

 -- C Function: int PyModule_AddType (PyObject *module, PyTypeObject
          *type)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Add a
     type object to 'module'.  The type object is finalized by calling
     internally *note PyType_Ready(): 77f.  The name of the type object
     is taken from the last component of *note tp_name: 1a56. after dot.
     Return ‘-1’ with an exception set on error, ‘0’ on success.

     Added in version 3.9.

 -- C Function: int PyUnstable_Module_SetGIL (PyObject *module, void
          *gil)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Indicate that 'module' does or does not support running without the
     global interpreter lock (GIL), using one of the values from *note
     Py_mod_gil: 158.  It must be called during 'module'’s
     initialization function.  If this function is not called during
     module initialization, the import machinery assumes the module does
     not support running without the GIL. This function is only
     available in Python builds configured with *note -disable-gil: 174.
     Return ‘-1’ with an exception set on error, ‘0’ on success.

     Added in version 3.13.


File: python.info,  Node: Module lookup,  Prev: Initializing C modules,  Up: Module Objects

7.8.6.8 Module lookup
.....................

Single-phase initialization creates singleton modules that can be looked
up in the context of the current interpreter.  This allows the module
object to be retrieved later with only a reference to the module
definition.

These functions will not work on modules created using multi-phase
initialization, since multiple such modules can be created from a single
definition.

 -- C Function: *note PyObject: 33a. *PyState_FindModule (PyModuleDef
          *def)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Returns the module object that was created from 'def' for
     the current interpreter.  This method requires that the module
     object has been attached to the interpreter state with *note
     PyState_AddModule(): 4d7c. beforehand.  In case the corresponding
     module object is not found or has not been attached to the
     interpreter state yet, it returns ‘NULL’.

 -- C Function: int PyState_AddModule (PyObject *module, PyModuleDef
          *def)
     ' Part of the *note Stable ABI: 556. since version 3.3.'  Attaches
     the module object passed to the function to the interpreter state.
     This allows the module object to be accessible via *note
     PyState_FindModule(): 4d7d.

     Only effective on modules created using single-phase
     initialization.

     Python calls ‘PyState_AddModule’ automatically after importing a
     module, so it is unnecessary (but harmless) to call it from module
     initialization code.  An explicit call is needed only if the
     module’s own init code subsequently calls ‘PyState_FindModule’.
     The function is mainly intended for implementing alternative import
     mechanisms (either by calling it directly, or by referring to its
     implementation for details of the required state updates).

     The caller must hold the GIL.

     Return ‘-1’ with an exception set on error, ‘0’ on success.

     Added in version 3.3.

 -- C Function: int PyState_RemoveModule (PyModuleDef *def)
     ' Part of the *note Stable ABI: 556. since version 3.3.'  Removes
     the module object created from 'def' from the interpreter state.
     Return ‘-1’ with an exception set on error, ‘0’ on success.

     The caller must hold the GIL.

     Added in version 3.3.


File: python.info,  Node: Iterator Objects,  Next: Descriptor Objects,  Prev: Module Objects,  Up: Other Objects

7.8.6.9 Iterator Objects
........................

Python provides two general-purpose iterator objects.  The first, a
sequence iterator, works with an arbitrary sequence supporting the *note
__getitem__(): 283. method.  The second works with a callable object and
a sentinel value, calling the callable for each item in the sequence,
and ending the iteration when the sentinel value is returned.

 -- C Variable: *note PyTypeObject: aba. PySeqIter_Type
     ' Part of the *note Stable ABI: 556.'  Type object for iterator
     objects returned by *note PySeqIter_New(): 4d64. and the
     one-argument form of the *note iter(): 7db. built-in function for
     built-in sequence types.

 -- C Function: int PySeqIter_Check (PyObject *op)

     Return true if the type of 'op' is *note PySeqIter_Type: 4d65.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PySeqIter_New (PyObject *seq)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return an iterator that works with a general sequence
     object, 'seq'.  The iteration ends when the sequence raises *note
     IndexError: 1585. for the subscripting operation.

 -- C Variable: *note PyTypeObject: aba. PyCallIter_Type
     ' Part of the *note Stable ABI: 556.'  Type object for iterator
     objects returned by *note PyCallIter_New(): 4c52. and the
     two-argument form of the *note iter(): 7db. built-in function.

 -- C Function: int PyCallIter_Check (PyObject *op)

     Return true if the type of 'op' is *note PyCallIter_Type: 4c53.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyCallIter_New (PyObject
          *callable, PyObject *sentinel)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new iterator.  The first parameter, 'callable', can
     be any Python callable object that can be called with no
     parameters; each call to it should return the next item in the
     iteration.  When 'callable' returns a value equal to 'sentinel',
     the iteration will be terminated.

* Menu:

* Range Objects::
* Builtin Iterator Types::
* Other Iterator Objects::


File: python.info,  Node: Range Objects,  Next: Builtin Iterator Types,  Up: Iterator Objects

7.8.6.10 Range Objects
......................

 -- C Variable: *note PyTypeObject: aba. PyRange_Type
     ' Part of the *note Stable ABI: 556.'  The type object for *note
     range: 94d. objects.

 -- C Function: int PyRange_Check (PyObject *o)

     Return true if the object 'o' is an instance of a *note range: 94d.
     object.  This function always succeeds.


File: python.info,  Node: Builtin Iterator Types,  Next: Other Iterator Objects,  Prev: Range Objects,  Up: Iterator Objects

7.8.6.11 Builtin Iterator Types
...............................

These are built-in iteration types that are included in Python’s C API,
but provide no additional functions.  They are here for completeness.

C type                                                 Python type
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Variable: *note PyTypeObject: aba. PyEnum_Type   *note enumerate: 14d0.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyTypeObject: aba.               *note filter: 86b.
          PyFilter_Type                                
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyMap_Type    *note map: 86a.
     ' Part of the *note Stable ABI: 556.'             

 -- C Variable: *note PyTypeObject: aba.               *note reversed: 86c.
          PyReversed_Type                              
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyZip_Type    *note zip: 7d4.
     ' Part of the *note Stable ABI: 556.'             


File: python.info,  Node: Other Iterator Objects,  Prev: Builtin Iterator Types,  Up: Iterator Objects

7.8.6.12 Other Iterator Objects
...............................

 -- C Variable: *note PyTypeObject: aba. PyByteArrayIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyBytesIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyListIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyListRevIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PySetIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyTupleIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyRangeIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyLongRangeIter_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyDictIterKey_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyDictRevIterKey_Type
     ' Part of the *note Stable ABI: 556. since version 3.8.'

 -- C Variable: *note PyTypeObject: aba. PyDictIterValue_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyDictRevIterValue_Type
     ' Part of the *note Stable ABI: 556. since version 3.8.'

 -- C Variable: *note PyTypeObject: aba. PyDictIterItem_Type
     ' Part of the *note Stable ABI: 556.'

 -- C Variable: *note PyTypeObject: aba. PyDictRevIterItem_Type
     ' Part of the *note Stable ABI: 556. since version 3.8.'

 -- C Variable: *note PyTypeObject: aba. PyODictIter_Type

     Type objects for iterators of various built-in objects.

     Do not create instances of these directly; prefer calling *note
     PyObject_GetIter(): 4d58. instead.

     Note that there is no guarantee that a given built-in type uses a
     given iterator type.  For example, iterating over *note range: 94d.
     will use one of two iterator types depending on the size of the
     range.  Other types may start using a similar scheme in the future,
     without warning.


File: python.info,  Node: Descriptor Objects,  Next: Slice Objects,  Prev: Iterator Objects,  Up: Other Objects

7.8.6.13 Descriptor Objects
...........................

“Descriptors” are objects that describe some attribute of an object.
They are found in the dictionary of type objects.

 -- C Variable: *note PyTypeObject: aba. PyProperty_Type
     ' Part of the *note Stable ABI: 556.'  The type object for the
     built-in descriptor types.

 -- C Function: *note PyObject: 33a. *PyDescr_NewGetSet (PyTypeObject
          *type, struct PyGetSetDef *getset)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

 -- C Function: *note PyObject: 33a. *PyDescr_NewMember (PyTypeObject
          *type, struct PyMemberDef *meth)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

 -- C Variable: *note PyTypeObject: aba. PyMemberDescr_Type
     ' Part of the *note Stable ABI: 556.'  The type object for member
     descriptor objects created from *note PyMemberDef: 552. structures.
     These descriptors expose fields of a C struct as attributes on a
     type, and correspond to *note types.MemberDescriptorType: 2739.
     objects in Python.

 -- C Variable: *note PyTypeObject: aba. PyGetSetDescr_Type
     ' Part of the *note Stable ABI: 556.'  The type object for get/set
     descriptor objects created from *note PyGetSetDef: bd7. structures.
     These descriptors implement attributes whose value is computed by C
     getter and setter functions, and are used for many built-in type
     attributes.

 -- C Function: *note PyObject: 33a. *PyDescr_NewMethod (PyTypeObject
          *type, struct PyMethodDef *meth)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

 -- C Variable: *note PyTypeObject: aba. PyMethodDescr_Type
     ' Part of the *note Stable ABI: 556.'  The type object for method
     descriptor objects created from *note PyMethodDef: 1526.
     structures.  These descriptors expose C functions as methods on a
     type, and correspond to *note types.MemberDescriptorType: 2739.
     objects in Python.

 -- C Function: *note PyObject: 33a. *PyDescr_NewWrapper (PyTypeObject
          *type, struct wrapperbase *wrapper, void *wrapped)
     'Return value: New reference.'

 -- C Variable: *note PyTypeObject: aba. PyWrapperDescr_Type
     ' Part of the *note Stable ABI: 556.'  The type object for wrapper
     descriptor objects created by *note PyDescr_NewWrapper(): 5105. and
     *note PyWrapper_New(): 4de6.  Wrapper descriptors are used
     internally to expose special methods implemented via wrapper
     structures, and appear in Python as *note
     types.WrapperDescriptorType: bb7. objects.

 -- C Function: *note PyObject: 33a. *PyDescr_NewClassMethod
          (PyTypeObject *type, PyMethodDef *method)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

 -- C Function: int PyDescr_IsData (PyObject *descr)

     Return non-zero if the descriptor object 'descr' describes a data
     attribute, or ‘0’ if it describes a method.  'descr' must be a
     descriptor object; there is no error checking.

 -- C Function: *note PyObject: 33a. *PyWrapper_New (PyObject*,
          PyObject*)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'

* Menu:

* Built-in descriptors::


File: python.info,  Node: Built-in descriptors,  Up: Descriptor Objects

7.8.6.14 Built-in descriptors
.............................

 -- C Variable: *note PyTypeObject: aba. PySuper_Type
     ' Part of the *note Stable ABI: 556.'  The type object for super
     objects.  This is the same object as *note super: 4de. in the
     Python layer.

 -- C Variable: *note PyTypeObject: aba. PyClassMethod_Type

     The type of class method objects.  This is the same object as *note
     classmethod: 166. in the Python layer.

 -- C Variable: *note PyTypeObject: aba. PyClassMethodDescr_Type
     ' Part of the *note Stable ABI: 556.'  The type object for C-level
     class method descriptor objects.  This is the type of the
     descriptors created for *note classmethod(): 166. defined in C
     extension types, and is the same object as *note classmethod: 166.
     in Python.

 -- C Function: *note PyObject: 33a. *PyClassMethod_New (PyObject
          *callable)

     Create a new *note classmethod: 166. object wrapping 'callable'.
     'callable' must be a callable object and must not be ‘NULL’.

     On success, this function returns a *note strong reference: 33e. to
     a new class method descriptor.  On failure, this function returns
     ‘NULL’ with an exception set.

 -- C Variable: *note PyTypeObject: aba. PyStaticMethod_Type

     The type of static method objects.  This is the same object as
     *note staticmethod: 419. in the Python layer.

 -- C Function: *note PyObject: 33a. *PyStaticMethod_New (PyObject
          *callable)

     Create a new *note staticmethod: 419. object wrapping 'callable'.
     'callable' must be a callable object and must not be ‘NULL’.

     On success, this function returns a *note strong reference: 33e. to
     a new static method descriptor.  On failure, this function returns
     ‘NULL’ with an exception set.


File: python.info,  Node: Slice Objects,  Next: MemoryView objects,  Prev: Descriptor Objects,  Up: Other Objects

7.8.6.15 Slice Objects
......................

 -- C Variable: *note PyTypeObject: aba. PySlice_Type
     ' Part of the *note Stable ABI: 556.'  The type object for slice
     objects.  This is the same as *note slice: 46c. in the Python
     layer.

 -- C Function: int PySlice_Check (PyObject *ob)

     Return true if 'ob' is a slice object; 'ob' must not be ‘NULL’.
     This function always succeeds.

 -- C Function: *note PyObject: 33a. *PySlice_New (PyObject *start,
          PyObject *stop, PyObject *step)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a new slice object with the given values.  The
     'start', 'stop', and 'step' parameters are used as the values of
     the slice object attributes of the same names.  Any of the values
     may be ‘NULL’, in which case the ‘None’ will be used for the
     corresponding attribute.

     Return ‘NULL’ with an exception set if the new object could not be
     allocated.

 -- C Function: int PySlice_GetIndices (PyObject *slice, Py_ssize_t
          length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
     ' Part of the *note Stable ABI: 556.'  Retrieve the start, stop and
     step indices from the slice object 'slice', assuming a sequence of
     length 'length'.  Treats indices greater than 'length' as errors.

     Returns ‘0’ on success and ‘-1’ on error with no exception set
     (unless one of the indices was not ‘None’ and failed to be
     converted to an integer, in which case ‘-1’ is returned with an
     exception set).

     You probably do not want to use this function.

     Changed in version 3.2: The parameter type for the 'slice'
     parameter was ‘PySliceObject*’ before.

 -- C Function: int PySlice_GetIndicesEx (PyObject *slice, Py_ssize_t
          length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
          Py_ssize_t *slicelength)
     ' Part of the *note Stable ABI: 556.'  Usable replacement for *note
     PySlice_GetIndices(): 4d79.  Retrieve the start, stop, and step
     indices from the slice object 'slice' assuming a sequence of length
     'length', and store the length of the slice in 'slicelength'.  Out
     of bounds indices are clipped in a manner consistent with the
     handling of normal slices.

     Return ‘0’ on success and ‘-1’ on error with an exception set.

          Note: This function is considered not safe for resizable
          sequences.  Its invocation should be replaced by a combination
          of *note PySlice_Unpack(): 400. and *note
          PySlice_AdjustIndices(): 401. where

               if (PySlice_GetIndicesEx(slice, length, &start, &stop, &step, &slicelength) < 0) {
                   // return error
               }

          is replaced by

               if (PySlice_Unpack(slice, &start, &stop, &step) < 0) {
                   // return error
               }
               slicelength = PySlice_AdjustIndices(length, &start, &stop, step);

     Changed in version 3.2: The parameter type for the 'slice'
     parameter was ‘PySliceObject*’ before.

     Changed in version 3.6.1: If ‘Py_LIMITED_API’ is not set or set to
     the value between ‘0x03050400’ and ‘0x03060000’ (not including) or
     ‘0x03060100’ or higher ‘PySlice_GetIndicesEx()’ is implemented as a
     macro using ‘PySlice_Unpack()’ and ‘PySlice_AdjustIndices()’.
     Arguments 'start', 'stop' and 'step' are evaluated more than once.

     Deprecated since version 3.6.1: If ‘Py_LIMITED_API’ is set to the
     value less than ‘0x03050400’ or between ‘0x03060000’ and
     ‘0x03060100’ (not including) ‘PySlice_GetIndicesEx()’ is a
     deprecated function.

 -- C Function: int PySlice_Unpack (PyObject *slice, Py_ssize_t *start,
          Py_ssize_t *stop, Py_ssize_t *step)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Extract
     the start, stop and step data members from a slice object as C
     integers.  Silently reduce values larger than ‘PY_SSIZE_T_MAX’ to
     ‘PY_SSIZE_T_MAX’, silently boost the start and stop values less
     than ‘PY_SSIZE_T_MIN’ to ‘PY_SSIZE_T_MIN’, and silently boost the
     step values less than ‘-PY_SSIZE_T_MAX’ to ‘-PY_SSIZE_T_MAX’.

     Return ‘-1’ with an exception set on error, ‘0’ on success.

     Added in version 3.6.1.

 -- C Function: *note Py_ssize_t: a6e. PySlice_AdjustIndices (Py_ssize_t
          length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Adjust
     start/end slice indices assuming a sequence of the specified
     length.  Out of bounds indices are clipped in a manner consistent
     with the handling of normal slices.

     Return the length of the slice.  Always successful.  Doesn’t call
     Python code.

     Added in version 3.6.1.

* Menu:

* Ellipsis Object::


File: python.info,  Node: Ellipsis Object,  Up: Slice Objects

7.8.6.16 Ellipsis Object
........................

 -- C Variable: *note PyTypeObject: aba. PyEllipsis_Type
     ' Part of the *note Stable ABI: 556.'  The type of Python *note
     Ellipsis: 233f. object.  Same as *note types.EllipsisType: 857. in
     the Python layer.

 -- C Variable: *note PyObject: 33a. *Py_Ellipsis

     The Python ‘Ellipsis’ object.  This object has no methods.  Like
     *note Py_None: 4b69, it is an *note immortal: 45dd. singleton
     object.

     Changed in version 3.12: *note Py_Ellipsis: 5111. is immortal.


File: python.info,  Node: MemoryView objects,  Next: Pickle buffer objects,  Prev: Slice Objects,  Up: Other Objects

7.8.6.17 MemoryView objects
...........................

A *note memoryview: 2eb. object exposes the C level *note buffer
interface: 2e8. as a Python object which can then be passed around like
any other object.

 -- C Variable: *note PyTypeObject: aba. PyMemoryView_Type
     ' Part of the *note Stable ABI: 556.'  This instance of *note
     PyTypeObject: aba. represents the Python memoryview type.  This is
     the same object as *note memoryview: 2eb. in the Python layer.

 -- C Function: *note PyObject: 33a. *PyMemoryView_FromObject (PyObject
          *obj)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a memoryview object from an object that provides the
     buffer interface.  If 'obj' supports writable buffer exports, the
     memoryview object will be read/write, otherwise it may be either
     read-only or read/write at the discretion of the exporter.

 -- C Macro: PyBUF_READ
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Flag to
     request a readonly buffer.

 -- C Macro: PyBUF_WRITE
     ' Part of the *note Stable ABI: 556. since version 3.11.'  Flag to
     request a writable buffer.

 -- C Function: *note PyObject: 33a. *PyMemoryView_FromMemory (char
          *mem, Py_ssize_t size, int flags)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.7.'  Create a memoryview object using 'mem' as the
     underlying buffer.  'flags' can be one of *note PyBUF_READ: 17a3.
     or *note PyBUF_WRITE: 17a4.

     Added in version 3.3.

 -- C Function: *note PyObject: 33a. *PyMemoryView_FromBuffer (const
          Py_buffer *view)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.11.'  Create a memoryview object wrapping the given
     buffer structure 'view'.  For simple byte buffers, *note
     PyMemoryView_FromMemory(): 11b4. is the preferred function.

 -- C Function: *note PyObject: 33a. *PyMemoryView_GetContiguous
          (PyObject *obj, int buffertype, char order)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a memoryview object to a *note contiguous: 23dc.
     chunk of memory (in either ‘C’ or ‘F’ortran 'order') from an object
     that defines the buffer interface.  If memory is contiguous, the
     memoryview object points to the original memory.  Otherwise, a copy
     is made and the memoryview points to a new bytes object.

     'buffertype' can be one of *note PyBUF_READ: 17a3. or *note
     PyBUF_WRITE: 17a4.

 -- C Function: int PyMemoryView_Check (PyObject *obj)

     Return true if the object 'obj' is a memoryview object.  It is not
     currently allowed to create subclasses of *note memoryview: 2eb.
     This function always succeeds.

 -- C Function: *note Py_buffer: 75b. *PyMemoryView_GET_BUFFER (PyObject
          *mview)

     Return a pointer to the memoryview’s private copy of the exporter’s
     buffer.  'mview' 'must' be a memoryview instance; this macro
     doesn’t check its type, you must do it yourself or you will risk
     crashes.

 -- C Function: *note PyObject: 33a. *PyMemoryView_GET_BASE (PyObject
          *mview)

     Return either a pointer to the exporting object that the memoryview
     is based on or ‘NULL’ if the memoryview has been created by one of
     the functions *note PyMemoryView_FromMemory(): 11b4. or *note
     PyMemoryView_FromBuffer(): 764.  'mview' 'must' be a memoryview
     instance.


File: python.info,  Node: Pickle buffer objects,  Next: Weak Reference Objects<2>,  Prev: MemoryView objects,  Up: Other Objects

7.8.6.18 Pickle buffer objects
..............................

Added in version 3.8.

A *note pickle.PickleBuffer: 15c6. object wraps a *note buffer-providing
object: 2e8. for out-of-band data transfer with the *note pickle: a6.
module.

 -- C Variable: *note PyTypeObject: aba. PyPickleBuffer_Type

     This instance of *note PyTypeObject: aba. represents the Python
     pickle buffer type.  This is the same object as *note
     pickle.PickleBuffer: 15c6. in the Python layer.

 -- C Function: int PyPickleBuffer_Check (PyObject *op)

     Return true if 'op' is a pickle buffer instance.  This function
     always succeeds.

 -- C Function: *note PyObject: 33a. *PyPickleBuffer_FromObject
          (PyObject *obj)

     Create a pickle buffer from the object 'obj'.

     This function will fail if 'obj' doesn’t support the *note buffer
     protocol: 2e8.

     On success, return a new pickle buffer instance.  On failure, set
     an exception and return ‘NULL’.

     Analogous to calling *note pickle.PickleBuffer: 15c6. with 'obj' in
     Python.

 -- C Function: const *note Py_buffer: 75b. *PyPickleBuffer_GetBuffer
          (PyObject *picklebuf)

     Get a pointer to the underlying *note Py_buffer: 75b. that the
     pickle buffer wraps.

     The returned pointer is valid as long as 'picklebuf' is alive and
     has not been released.  The caller must not modify or free the
     returned *note Py_buffer: 75b.  If the pickle buffer has been
     released, raise *note ValueError: 202.

     On success, return a pointer to the buffer view.  On failure, set
     an exception and return ‘NULL’.

 -- C Function: int PyPickleBuffer_Release (PyObject *picklebuf)

     Release the underlying buffer held by the pickle buffer.

     Return ‘0’ on success.  On failure, set an exception and return
     ‘-1’.

     Analogous to calling *note pickle.PickleBuffer.release(): 2a70. in
     Python.


File: python.info,  Node: Weak Reference Objects<2>,  Next: Capsules<2>,  Prev: Pickle buffer objects,  Up: Other Objects

7.8.6.19 Weak Reference Objects
...............................

Python supports 'weak references' as first-class objects.  There are two
specific object types which directly implement weak references.  The
first is a simple reference object, and the second acts as a proxy for
the original object as much as it can.

 -- C Function: int PyWeakref_Check (PyObject *ob)

     Return non-zero if 'ob' is either a reference or proxy object.
     This function always succeeds.

 -- C Function: int PyWeakref_CheckRef (PyObject *ob)

     Return non-zero if 'ob' is a reference object or a subclass of the
     reference type.  This function always succeeds.

 -- C Function: int PyWeakref_CheckRefExact (PyObject *ob)

     Return non-zero if 'ob' is a reference object, but not a subclass
     of the reference type.  This function always succeeds.

 -- C Function: int PyWeakref_CheckProxy (PyObject *ob)

     Return non-zero if 'ob' is a proxy object.  This function always
     succeeds.

 -- C Function: *note PyObject: 33a. *PyWeakref_NewRef (PyObject *ob,
          PyObject *callback)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a weak reference object for the object 'ob'.  This
     will always return a new reference, but is not guaranteed to create
     a new object; an existing reference object may be returned.  The
     second parameter, 'callback', can be a callable object that
     receives notification when 'ob' is garbage collected; it should
     accept a single parameter, which will be the weak reference object
     itself.  'callback' may also be ‘None’ or ‘NULL’.  If 'ob' is not a
     weakly referenceable object, or if 'callback' is not callable,
     ‘None’, or ‘NULL’, this will return ‘NULL’ and raise *note
     TypeError: 2c3.

     See also
     ........

     *note PyType_SUPPORTS_WEAKREFS(): 4f98. for checking if 'ob' is
     weakly referenceable.

 -- C Function: *note PyObject: 33a. *PyWeakref_NewProxy (PyObject *ob,
          PyObject *callback)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Return a weak reference proxy object for the object 'ob'.
     This will always return a new reference, but is not guaranteed to
     create a new object; an existing proxy object may be returned.  The
     second parameter, 'callback', can be a callable object that
     receives notification when 'ob' is garbage collected; it should
     accept a single parameter, which will be the weak reference object
     itself.  'callback' may also be ‘None’ or ‘NULL’.  If 'ob' is not a
     weakly referenceable object, or if 'callback' is not callable,
     ‘None’, or ‘NULL’, this will return ‘NULL’ and raise *note
     TypeError: 2c3.

     See also
     ........

     *note PyType_SUPPORTS_WEAKREFS(): 4f98. for checking if 'ob' is
     weakly referenceable.

 -- C Function: int PyWeakref_GetRef (PyObject *ref, PyObject **pobj)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Get a
     *note strong reference: 33e. to the referenced object from a weak
     reference, 'ref', into '*pobj'.

        * On success, set '*pobj' to a new *note strong reference: 33e.
          to the referenced object and return 1.

        * If the reference is dead, set '*pobj' to ‘NULL’ and return 0.

        * On error, raise an exception and return -1.

     Added in version 3.13.

 -- C Function: *note PyObject: 33a. *PyWeakref_GetObject (PyObject
          *ref)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return a *note borrowed reference: 33f. to the referenced
     object from a weak reference, 'ref'.  If the referent is no longer
     live, returns ‘Py_None’.

          Note: This function returns a *note borrowed reference: 33f.
          to the referenced object.  This means that you should always
          call *note Py_INCREF(): 571. on the object except when it
          cannot be destroyed before the last usage of the borrowed
          reference.

     Deprecated since version 3.13, will be removed in version 3.15: Use
     *note PyWeakref_GetRef(): 37b. instead.

 -- C Function: *note PyObject: 33a. *PyWeakref_GET_OBJECT (PyObject
          *ref)
     'Return value: Borrowed reference.'  Similar to *note
     PyWeakref_GetObject(): 37c, but does no error checking.

     Deprecated since version 3.13, will be removed in version 3.15: Use
     *note PyWeakref_GetRef(): 37b. instead.

 -- C Function: void PyObject_ClearWeakRefs (PyObject *object)
     ' Part of the *note Stable ABI: 556.'  This function is called by
     the *note tp_dealloc: 4b87. handler to clear weak references.

     This iterates through the weak references for 'object' and calls
     callbacks for those references which have one.  It returns when all
     callbacks have been attempted.

 -- C Function: void PyUnstable_Object_ClearWeakRefsNoCallbacks
          (PyObject *object)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Clears the weakrefs for 'object' without calling the callbacks.

     This function is called by the *note tp_dealloc: 4b87. handler for
     types with finalizers (i.e., *note __del__(): 1038.).  The handler
     for those objects first calls *note PyObject_ClearWeakRefs(): 579.
     to clear weakrefs and call their callbacks, then the finalizer, and
     finally this function to clear any weakrefs that may have been
     created by the finalizer.

     In most circumstances, it’s more appropriate to use *note
     PyObject_ClearWeakRefs(): 579. to clear weakrefs instead of this
     function.

     Added in version 3.13.


File: python.info,  Node: Capsules<2>,  Next: Frame Objects,  Prev: Weak Reference Objects<2>,  Up: Other Objects

7.8.6.20 Capsules
.................

Refer to *note Providing a C API for an Extension Module: 13aa. for more
information on using these objects.

Added in version 3.1.

 -- C Type: type PyCapsule

     This subtype of *note PyObject: 33a. represents an opaque value,
     useful for C extension modules which need to pass an opaque value
     (as a void* pointer) through Python code to other C code.  It is
     often used to make a C function pointer defined in one module
     available to other modules, so the regular import mechanism can be
     used to access C APIs defined in dynamically loaded modules.

 -- C Variable: *note PyTypeObject: aba. PyCapsule_Type
     ' Part of the *note Stable ABI: 556.'  The type object
     corresponding to capsule objects.  This is the same object as *note
     types.CapsuleType: 273f. in the Python layer.

 -- C Type: type PyCapsule_Destructor
     ' Part of the *note Stable ABI: 556.'  The type of a destructor
     callback for a capsule.  Defined as:

          typedef void (*PyCapsule_Destructor)(PyObject *);

     See *note PyCapsule_New(): 4b8e. for the semantics of
     PyCapsule_Destructor callbacks.

 -- C Function: int PyCapsule_CheckExact (PyObject *p)

     Return true if its argument is a *note PyCapsule: 12b9.  This
     function always succeeds.

 -- C Function: *note PyObject: 33a. *PyCapsule_New (void *pointer,
          const char *name, PyCapsule_Destructor destructor)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Create a *note PyCapsule: 12b9. encapsulating the 'pointer'.
     The 'pointer' argument may not be ‘NULL’.

     On failure, set an exception and return ‘NULL’.

     The 'name' string may either be ‘NULL’ or a pointer to a valid C
     string.  If non-‘NULL’, this string must outlive the capsule.
     (Though it is permitted to free it inside the 'destructor'.)

     If the 'destructor' argument is not ‘NULL’, it will be called with
     the capsule as its argument when it is destroyed.

     If this capsule will be stored as an attribute of a module, the
     'name' should be specified as ‘modulename.attributename’.  This
     will enable other modules to import the capsule using *note
     PyCapsule_Import(): 19b4.

 -- C Function: void *PyCapsule_GetPointer (PyObject *capsule, const
          char *name)
     ' Part of the *note Stable ABI: 556.'  Retrieve the 'pointer'
     stored in the capsule.  On failure, set an exception and return
     ‘NULL’.

     The 'name' parameter must compare exactly to the name stored in the
     capsule.  If the name stored in the capsule is ‘NULL’, the 'name'
     passed in must also be ‘NULL’.  Python uses the C function
     ‘strcmp()’ to compare capsule names.

 -- C Function: *note PyCapsule_Destructor: 4c55.
          PyCapsule_GetDestructor (PyObject *capsule)
     ' Part of the *note Stable ABI: 556.'  Return the current
     destructor stored in the capsule.  On failure, set an exception and
     return ‘NULL’.

     It is legal for a capsule to have a ‘NULL’ destructor.  This makes
     a ‘NULL’ return code somewhat ambiguous; use *note
     PyCapsule_IsValid(): 13a9. or *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Function: void *PyCapsule_GetContext (PyObject *capsule)
     ' Part of the *note Stable ABI: 556.'  Return the current context
     stored in the capsule.  On failure, set an exception and return
     ‘NULL’.

     It is legal for a capsule to have a ‘NULL’ context.  This makes a
     ‘NULL’ return code somewhat ambiguous; use *note
     PyCapsule_IsValid(): 13a9. or *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Function: const char *PyCapsule_GetName (PyObject *capsule)
     ' Part of the *note Stable ABI: 556.'  Return the current name
     stored in the capsule.  On failure, set an exception and return
     ‘NULL’.

     It is legal for a capsule to have a ‘NULL’ name.  This makes a
     ‘NULL’ return code somewhat ambiguous; use *note
     PyCapsule_IsValid(): 13a9. or *note PyErr_Occurred(): 1a55. to
     disambiguate.

 -- C Function: void *PyCapsule_Import (const char *name, int no_block)
     ' Part of the *note Stable ABI: 556.'  Import a pointer to a C
     object from a capsule attribute in a module.  The 'name' parameter
     should specify the full name to the attribute, as in
     ‘module.attribute’.  The 'name' stored in the capsule must match
     this string exactly.

     This function splits 'name' on the ‘.’ character, and imports the
     first element.  It then processes further elements using attribute
     lookups.

     Return the capsule’s internal 'pointer' on success.  On failure,
     set an exception and return ‘NULL’.

          Note: If 'name' points to an attribute of some submodule or
          subpackage, this submodule or subpackage must be previously
          imported using other means (for example, by using *note
          PyImport_ImportModule(): 3c1.) for the attribute lookups to
          succeed.

     Changed in version 3.3: 'no_block' has no effect anymore.

 -- C Function: int PyCapsule_IsValid (PyObject *capsule, const char
          *name)
     ' Part of the *note Stable ABI: 556.'  Determines whether or not
     'capsule' is a valid capsule.  A valid capsule is non-‘NULL’,
     passes *note PyCapsule_CheckExact(): 512b, has a non-‘NULL’ pointer
     stored in it, and its internal name matches the 'name' parameter.
     (See *note PyCapsule_GetPointer(): 4c59. for information on how
     capsule names are compared.)

     In other words, if *note PyCapsule_IsValid(): 13a9. returns a true
     value, calls to any of the accessors (any function starting with
     ‘PyCapsule_Get’) are guaranteed to succeed.

     Return a nonzero value if the object is valid and matches the name
     passed in.  Return ‘0’ otherwise.  This function will not fail.

 -- C Function: int PyCapsule_SetContext (PyObject *capsule, void
          *context)
     ' Part of the *note Stable ABI: 556.'  Set the context pointer
     inside 'capsule' to 'context'.

     Return ‘0’ on success.  Return nonzero and set an exception on
     failure.

 -- C Function: int PyCapsule_SetDestructor (PyObject *capsule,
          PyCapsule_Destructor destructor)
     ' Part of the *note Stable ABI: 556.'  Set the destructor inside
     'capsule' to 'destructor'.

     Return ‘0’ on success.  Return nonzero and set an exception on
     failure.

 -- C Function: int PyCapsule_SetName (PyObject *capsule, const char
          *name)
     ' Part of the *note Stable ABI: 556.'  Set the name inside
     'capsule' to 'name'.  If non-‘NULL’, the name must outlive the
     capsule.  If the previous 'name' stored in the capsule was not
     ‘NULL’, no attempt is made to free it.

     Return ‘0’ on success.  Return nonzero and set an exception on
     failure.

 -- C Function: int PyCapsule_SetPointer (PyObject *capsule, void
          *pointer)
     ' Part of the *note Stable ABI: 556.'  Set the void pointer inside
     'capsule' to 'pointer'.  The pointer may not be ‘NULL’.

     Return ‘0’ on success.  Return nonzero and set an exception on
     failure.


File: python.info,  Node: Frame Objects,  Next: Generator Objects,  Prev: Capsules<2>,  Up: Other Objects

7.8.6.21 Frame Objects
......................

 -- C Type: type PyFrameObject
     ' Part of the *note Limited API: 556. (as an opaque struct).'  The
     C structure of the objects used to describe frame objects.

     There are no public members in this structure.

     Changed in version 3.11: The members of this structure were removed
     from the public C API. Refer to the *note What’s New entry: 78b.
     for details.

The *note PyEval_GetFrame(): 18dc. and *note PyThreadState_GetFrame():
791. functions can be used to get a frame object.

See also *note Reflection: 4f13.

 -- C Variable: *note PyTypeObject: aba. PyFrame_Type

     The type of frame objects.  It is the same object as *note
     types.FrameType: 1992. in the Python layer.

     Changed in version 3.11: Previously, this type was only available
     after including ‘<frameobject.h>’.

 -- C Function: *note PyFrameObject: 78c. *PyFrame_New (PyThreadState
          *tstate, PyCodeObject *code, PyObject *globals, PyObject
          *locals)

     Create a new frame object.  This function returns a *note strong
     reference: 33e. to the new frame object on success, and returns
     ‘NULL’ with an exception set on failure.

 -- C Function: int PyFrame_Check (PyObject *obj)

     Return non-zero if 'obj' is a frame object.

     Changed in version 3.11: Previously, this function was only
     available after including ‘<frameobject.h>’.

 -- C Function: *note PyFrameObject: 78c. *PyFrame_GetBack
          (PyFrameObject *frame)
     'Return value: New reference.'  Get the 'frame' next outer frame.

     Return a *note strong reference: 33e, or ‘NULL’ if 'frame' has no
     outer frame.  This raises no exceptions.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyFrame_GetBuiltins (PyFrameObject
          *frame)
     'Return value: New reference.'  Get the 'frame'’s *note f_builtins:
     2102. attribute.

     Return a *note strong reference: 33e.  The result cannot be ‘NULL’.

     Added in version 3.11.

 -- C Function: *note PyCodeObject: 77a. *PyFrame_GetCode (PyFrameObject
          *frame)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.10.'  Get the 'frame' code.

     Return a *note strong reference: 33e.

     The result (frame code) cannot be ‘NULL’.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyFrame_GetGenerator
          (PyFrameObject *frame)
     'Return value: New reference.'  Get the generator, coroutine, or
     async generator that owns this frame, or ‘NULL’ if this frame is
     not owned by a generator.  Does not raise an exception, even if the
     return value is ‘NULL’.

     Return a *note strong reference: 33e, or ‘NULL’.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyFrame_GetGlobals (PyFrameObject
          *frame)
     'Return value: New reference.'  Get the 'frame'’s *note f_globals:
     2101. attribute.

     Return a *note strong reference: 33e.  The result cannot be ‘NULL’.

     Added in version 3.11.

 -- C Function: int PyFrame_GetLasti (PyFrameObject *frame)

     Get the 'frame'’s *note f_lasti: 88f. attribute.

     Returns -1 if ‘frame.f_lasti’ is ‘None’.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a. *PyFrame_GetVar (PyFrameObject
          *frame, PyObject *name)
     'Return value: New reference.'  Get the variable 'name' of 'frame'.

        * Return a *note strong reference: 33e. to the variable value on
          success.

        * Raise *note NameError: 442. and return ‘NULL’ if the variable
          does not exist.

        * Raise an exception and return ‘NULL’ on error.

     'name' type must be a *note str: 44f.

     Added in version 3.12.

 -- C Function: *note PyObject: 33a. *PyFrame_GetVarString
          (PyFrameObject *frame, const char *name)
     'Return value: New reference.'  Similar to *note PyFrame_GetVar():
     56b, but the variable name is a C string encoded in UTF-8.

     Added in version 3.12.

 -- C Function: *note PyObject: 33a. *PyFrame_GetLocals (PyFrameObject
          *frame)
     'Return value: New reference.'  Get the 'frame'’s *note f_locals:
     182. attribute.  If the frame refers to an *note optimized scope:
     17e, this returns a write-through proxy object that allows
     modifying the locals.  In all other cases (classes, modules, *note
     exec(): 17f, *note eval(): 180.) it returns the mapping
     representing the frame locals directly (as described for *note
     locals(): 141.).

     Return a *note strong reference: 33e.

     Added in version 3.11.

     Changed in version 3.13: As part of PEP 667(1), return an instance
     of *note PyFrameLocalsProxy_Type: 512f.

 -- C Function: int PyFrame_GetLineNumber (PyFrameObject *frame)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Return
     the line number that 'frame' is currently executing.

* Menu:

* Frame Locals Proxies::
* Legacy Local Variable APIs::
* Internal Frames::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/


File: python.info,  Node: Frame Locals Proxies,  Next: Legacy Local Variable APIs,  Up: Frame Objects

7.8.6.22 Frame Locals Proxies
.............................

Added in version 3.13.

The *note f_locals: 182. attribute on a *note frame object: 6e3. is an
instance of a “frame-locals proxy”.  The proxy object exposes a
write-through view of the underlying locals dictionary for the frame.
This ensures that the variables exposed by ‘f_locals’ are always up to
date with the live local variables in the frame itself.

See PEP 667(1) for more information.

 -- C Variable: *note PyTypeObject: aba. PyFrameLocalsProxy_Type

     The type of frame *note locals(): 141. proxy objects.

 -- C Function: int PyFrameLocalsProxy_Check (PyObject *obj)

     Return non-zero if 'obj' is a frame *note locals(): 141. proxy.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/


File: python.info,  Node: Legacy Local Variable APIs,  Next: Internal Frames,  Prev: Frame Locals Proxies,  Up: Frame Objects

7.8.6.23 Legacy Local Variable APIs
...................................

These APIs are *note soft deprecated: 209.  As of Python 3.13, they do
nothing.  They exist solely for backwards compatibility.

 -- C Function: void PyFrame_LocalsToFast (PyFrameObject *f, int clear)

     This function is *note soft deprecated: 209. and does nothing.

     Prior to Python 3.13, this function would copy the *note f_locals:
     182. attribute of 'f' to the internal “fast” array of local
     variables, allowing changes in frame objects to be visible to the
     interpreter.  If 'clear' was true, this function would process
     variables that were unset in the locals dictionary.

     Changed in version 3.13: This function now does nothing.

 -- C Function: void PyFrame_FastToLocals (PyFrameObject *f)

     This function is *note soft deprecated: 209. and does nothing.

     Prior to Python 3.13, this function would copy the internal “fast”
     array of local variables (which is used by the interpreter) to the
     *note f_locals: 182. attribute of 'f', allowing changes in local
     variables to be visible to frame objects.

     Changed in version 3.13: This function now does nothing.

 -- C Function: int PyFrame_FastToLocalsWithError (PyFrameObject *f)

     This function is *note soft deprecated: 209. and does nothing.

     Prior to Python 3.13, this function was similar to *note
     PyFrame_FastToLocals(): 5134, but would return ‘0’ on success, and
     ‘-1’ with an exception set on failure.

     Changed in version 3.13: This function now does nothing.

See also
........

PEP 667(1)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0667/


File: python.info,  Node: Internal Frames,  Prev: Legacy Local Variable APIs,  Up: Frame Objects

7.8.6.24 Internal Frames
........................

Unless using PEP 523(1), you will not need this.

 -- C Struct: struct _PyInterpreterFrame

     The interpreter’s internal frame representation.

     Added in version 3.11.

 -- C Function: *note PyObject: 33a.
          *PyUnstable_InterpreterFrame_GetCode (struct
          _PyInterpreterFrame *frame);

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
          Return a *note strong reference: 33e. to the code object for
          the frame.

     Added in version 3.12.

 -- C Function: int PyUnstable_InterpreterFrame_GetLasti (struct
          _PyInterpreterFrame *frame);

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return the byte offset into the last executed instruction.

     Added in version 3.12.

 -- C Function: int PyUnstable_InterpreterFrame_GetLine (struct
          _PyInterpreterFrame *frame);

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return the currently executing line number, or -1 if there is no
     line number.

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0523/


File: python.info,  Node: Generator Objects,  Next: Coroutine Objects<2>,  Prev: Frame Objects,  Up: Other Objects

7.8.6.25 Generator Objects
..........................

Generator objects are what Python uses to implement generator iterators.
They are normally created by iterating over a function that yields
values, rather than explicitly calling *note PyGen_New(): 513f. or *note
PyGen_NewWithQualName(): 5140.

 -- C Type: type PyGenObject

     The C structure used for generator objects.

 -- C Variable: *note PyTypeObject: aba. PyGen_Type

     The type object corresponding to generator objects.

 -- C Function: int PyGen_Check (PyObject *ob)

     Return true if 'ob' is a generator object; 'ob' must not be ‘NULL’.
     This function always succeeds.

 -- C Function: int PyGen_CheckExact (PyObject *ob)

     Return true if 'ob'’s type is *note PyGen_Type: 5142.; 'ob' must
     not be ‘NULL’.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyGen_New (PyFrameObject *frame)
     'Return value: New reference.'  Create and return a new generator
     object based on the 'frame' object.  A reference to 'frame' is
     stolen by this function.  The argument must not be ‘NULL’.

 -- C Function: *note PyObject: 33a. *PyGen_NewWithQualName
          (PyFrameObject *frame, PyObject *name, PyObject *qualname)
     'Return value: New reference.'  Create and return a new generator
     object based on the 'frame' object, with ‘__name__’ and
     ‘__qualname__’ set to 'name' and 'qualname'.  A reference to
     'frame' is stolen by this function.  The 'frame' argument must not
     be ‘NULL’.

 -- C Function: *note PyCodeObject: 77a. *PyGen_GetCode (PyGenObject
          *gen)

     Return a new *note strong reference: 33e. to the code object
     wrapped by 'gen'.  This function always succeeds.

* Menu:

* Asynchronous Generator Objects::


File: python.info,  Node: Asynchronous Generator Objects,  Up: Generator Objects

7.8.6.26 Asynchronous Generator Objects
.......................................

See also
........

PEP 525(1)

 -- C Variable: *note PyTypeObject: aba. PyAsyncGen_Type

     The type object corresponding to asynchronous generator objects.
     This is available as *note types.AsyncGeneratorType: 2734. in the
     Python layer.

     Added in version 3.6.

 -- C Function: *note PyObject: 33a. *PyAsyncGen_New (PyFrameObject
          *frame, PyObject *name, PyObject *qualname)

     Create a new asynchronous generator wrapping 'frame', with
     ‘__name__’ and ‘__qualname__’ set to 'name' and 'qualname'.
     'frame' is stolen by this function and must not be ‘NULL’.

     On success, this function returns a *note strong reference: 33e. to
     the new asynchronous generator.  On failure, this function returns
     ‘NULL’ with an exception set.

     Added in version 3.6.

 -- C Function: int PyAsyncGen_CheckExact (PyObject *op)

     Return true if 'op' is an asynchronous generator object, false
     otherwise.  This function always succeeds.

     Added in version 3.6.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0525/


File: python.info,  Node: Coroutine Objects<2>,  Next: Context Variables Objects,  Prev: Generator Objects,  Up: Other Objects

7.8.6.27 Coroutine Objects
..........................

Added in version 3.5.

Coroutine objects are what functions declared with an ‘async’ keyword
return.

 -- C Type: type PyCoroObject

     The C structure used for coroutine objects.

 -- C Variable: *note PyTypeObject: aba. PyCoro_Type

     The type object corresponding to coroutine objects.

 -- C Function: int PyCoro_CheckExact (PyObject *ob)

     Return true if 'ob'’s type is *note PyCoro_Type: 514e.; 'ob' must
     not be ‘NULL’.  This function always succeeds.

 -- C Function: *note PyObject: 33a. *PyCoro_New (PyFrameObject *frame,
          PyObject *name, PyObject *qualname)
     'Return value: New reference.'  Create and return a new coroutine
     object based on the 'frame' object, with ‘__name__’ and
     ‘__qualname__’ set to 'name' and 'qualname'.  A reference to
     'frame' is stolen by this function.  The 'frame' argument must not
     be ‘NULL’.


File: python.info,  Node: Context Variables Objects,  Next: Objects for Type Hinting,  Prev: Coroutine Objects<2>,  Up: Other Objects

7.8.6.28 Context Variables Objects
..................................

Added in version 3.7.

Changed in version 3.7.1:

     Note: In Python 3.7.1 the signatures of all context variables C
     APIs were 'changed' to use *note PyObject: 33a. pointers instead of
     *note PyContext: 5154, *note PyContextVar: 5155, and *note
     PyContextToken: 5156, e.g.:

          // in 3.7.0:
          PyContext *PyContext_New(void);

          // in 3.7.1+:
          PyObject *PyContext_New(void);

     See bpo-34762(1) for more details.

This section details the public C API for the *note contextvars: 24.
module.

 -- C Type: type PyContext

     The C structure used to represent a *note contextvars.Context:
     15dd. object.

 -- C Type: type PyContextVar

     The C structure used to represent a *note contextvars.ContextVar:
     1662. object.

 -- C Type: type PyContextToken

     The C structure used to represent a *note contextvars.Token: 346d.
     object.

 -- C Variable: *note PyTypeObject: aba. PyContext_Type

     The type object representing the 'context' type.

 -- C Variable: *note PyTypeObject: aba. PyContextVar_Type

     The type object representing the 'context variable' type.

 -- C Variable: *note PyTypeObject: aba. PyContextToken_Type

     The type object representing the 'context variable token' type.

Type-check macros:

 -- C Function: int PyContext_CheckExact (PyObject *o)

     Return true if 'o' is of type *note PyContext_Type: 5157.  'o' must
     not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyContextVar_CheckExact (PyObject *o)

     Return true if 'o' is of type *note PyContextVar_Type: 5158.  'o'
     must not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyContextToken_CheckExact (PyObject *o)

     Return true if 'o' is of type *note PyContextToken_Type: 5159.  'o'
     must not be ‘NULL’.  This function always succeeds.

Context object management functions:

 -- C Function: *note PyObject: 33a. *PyContext_New (void)
     'Return value: New reference.'  Create a new empty context object.
     Returns ‘NULL’ if an error has occurred.

 -- C Function: *note PyObject: 33a. *PyContext_Copy (PyObject *ctx)
     'Return value: New reference.'  Create a shallow copy of the passed
     'ctx' context object.  Returns ‘NULL’ if an error has occurred.

 -- C Function: *note PyObject: 33a. *PyContext_CopyCurrent (void)
     'Return value: New reference.'  Create a shallow copy of the
     current thread context.  Returns ‘NULL’ if an error has occurred.

 -- C Function: int PyContext_Enter (PyObject *ctx)

     Set 'ctx' as the current context for the current thread.  Returns
     ‘0’ on success, and ‘-1’ on error.

 -- C Function: int PyContext_Exit (PyObject *ctx)

     Deactivate the 'ctx' context and restore the previous context as
     the current context for the current thread.  Returns ‘0’ on
     success, and ‘-1’ on error.

Context variable functions:

 -- C Function: *note PyObject: 33a. *PyContextVar_New (const char
          *name, PyObject *def)
     'Return value: New reference.'  Create a new ‘ContextVar’ object.
     The 'name' parameter is used for introspection and debug purposes.
     The 'def' parameter specifies a default value for the context
     variable, or ‘NULL’ for no default.  If an error has occurred, this
     function returns ‘NULL’.

 -- C Function: int PyContextVar_Get (PyObject *var, PyObject
          *default_value, PyObject **value)

     Get the value of a context variable.  Returns ‘-1’ if an error has
     occurred during lookup, and ‘0’ if no error occurred, whether or
     not a value was found.

     If the context variable was found, 'value' will be a pointer to it.
     If the context variable was 'not' found, 'value' will point to:

        - 'default_value', if not ‘NULL’;

        - the default value of 'var', if not ‘NULL’;

        - ‘NULL’

     Except for ‘NULL’, the function returns a new reference.

 -- C Function: *note PyObject: 33a. *PyContextVar_Set (PyObject *var,
          PyObject *value)
     'Return value: New reference.'  Set the value of 'var' to 'value'
     in the current context.  Returns a new token object for this
     change, or ‘NULL’ if an error has occurred.

 -- C Function: int PyContextVar_Reset (PyObject *var, PyObject *token)

     Reset the state of the 'var' context variable to that it was in
     before *note PyContextVar_Set(): 5164. that returned the 'token'
     was called.  This function returns ‘0’ on success and ‘-1’ on
     error.

   ---------- Footnotes ----------

   (1) https://bugs.python.org/issue?@action=redirect&bpo=34762


File: python.info,  Node: Objects for Type Hinting,  Prev: Context Variables Objects,  Up: Other Objects

7.8.6.29 Objects for Type Hinting
.................................

Various built-in types for type hinting are provided.  Currently, two
types exist – *note GenericAlias: 6b5. and *note Union: 7c6.  Only
‘GenericAlias’ is exposed to C.

 -- C Function: *note PyObject: 33a. *Py_GenericAlias (PyObject *origin,
          PyObject *args)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Create a
     *note GenericAlias: 6b5. object.  Equivalent to calling the Python
     class *note types.GenericAlias: 7f0.  The 'origin' and 'args'
     arguments set the ‘GenericAlias’‘s ‘__origin__’ and ‘__args__’
     attributes respectively.  'origin' should be a *note PyTypeObject:
     aba.*, and 'args' can be a *note PyTupleObject: 4ed5.* or any
     ‘PyObject*’.  If 'args' passed is not a tuple, a 1-tuple is
     automatically constructed and ‘__args__’ is set to ‘(args,)’.
     Minimal checking is done for the arguments, so the function will
     succeed even if 'origin' is not a type.  The ‘GenericAlias’‘s
     ‘__parameters__’ attribute is constructed lazily from ‘__args__’.
     On failure, an exception is raised and ‘NULL’ is returned.

     Here’s an example of how to make an extension type generic:

          ...
          static PyMethodDef my_obj_methods[] = {
              // Other methods.
              ...
              {"__class_getitem__", Py_GenericAlias, METH_O|METH_CLASS, "See PEP 585"}
              ...
          }

     See also
     ........

     The data model method *note __class_getitem__(): 73e.

     Added in version 3.9.

 -- C Variable: *note PyTypeObject: aba. Py_GenericAliasType
     ' Part of the *note Stable ABI: 556. since version 3.9.'  The C
     type of the object returned by *note Py_GenericAlias(): 4deb.
     Equivalent to *note types.GenericAlias: 7f0. in Python.

     Added in version 3.9.


File: python.info,  Node: C API for extension modules,  Prev: Other Objects,  Up: Concrete Objects Layer

7.8.7 C API for extension modules
---------------------------------

* Menu:

* Curses C API::
* Internal data::
* DateTime Objects: DateTime Objects<2>.
* Internal data: Internal data<2>.


File: python.info,  Node: Curses C API,  Next: Internal data,  Up: C API for extension modules

7.8.7.1 Curses C API
....................

*note curses: 2b. exposes a small C interface for extension modules.
Consumers must include the header file ‘py_curses.h’ (which is not
included by default by ‘Python.h’) and *note import_curses(): 516d. must
be invoked, usually as part of the module initialisation function, to
populate *note PyCurses_API: 516e.

     Warning: Neither the C API nor the pure Python *note curses: 2b.
     module are compatible with subinterpreters.

 -- C Macro: import_curses ()

     Import the curses C API. The macro does not need a semi-colon to be
     called.

     On success, populate the *note PyCurses_API: 516e. pointer.

     On failure, set *note PyCurses_API: 516e. to NULL and set an
     exception.  The caller must check if an error occurred via *note
     PyErr_Occurred(): 1a55.:

          import_curses();  // semi-colon is optional but recommended
          if (PyErr_Occurred()) { /* cleanup */ }

 -- C Variable: void **PyCurses_API

     Dynamically allocated object containing the curses C API. This
     variable is only available once *note import_curses: 516d.
     succeeds.

     ‘PyCurses_API[0]’ corresponds to *note PyCursesWindow_Type: 516f.

     ‘PyCurses_API[1]’, ‘PyCurses_API[2]’, and ‘PyCurses_API[3]’ are
     pointers to predicate functions of type ‘int (*)(void)’.

     When called, these predicates return whether *note
     curses.setupterm(): 319d, *note curses.initscr(): 16a7, and *note
     curses.start_color(): 319e. have been called respectively.

     See also the convenience macros *note PyCursesSetupTermCalled:
     5170, *note PyCursesInitialised: 5171, and *note
     PyCursesInitialisedColor: 5172.

          Note: The number of entries in this structure is subject to
          changes.  Consider using *note PyCurses_API_pointers: 5173. to
          check if new fields are available or not.

 -- C Macro: PyCurses_API_pointers

     The number of accessible fields (‘4’) in *note PyCurses_API: 516e.
     This number is incremented whenever new fields are added.

 -- C Variable: *note PyTypeObject: aba. PyCursesWindow_Type

     The *note heap type: 96f. corresponding to *note curses.window:
     10d9.

 -- C Function: int PyCursesWindow_Check (PyObject *op)

     Return true if 'op' is a *note curses.window: 10d9. instance, false
     otherwise.

The following macros are convenience macros expanding into C statements.
In particular, they can only be used as ‘macro;’ or ‘macro’, but not
‘macro()’ or ‘macro();’.

 -- C Macro: PyCursesSetupTermCalled

     Macro checking if *note curses.setupterm(): 319d. has been called.

     The macro expansion is roughly equivalent to:

          {
              typedef int (*predicate_t)(void);
              predicate_t was_setupterm_called = (predicate_t)PyCurses_API[1];
              if (!was_setupterm_called()) {
                  return NULL;
              }
          }

 -- C Macro: PyCursesInitialised

     Macro checking if *note curses.initscr(): 16a7. has been called.

     The macro expansion is roughly equivalent to:

          {
              typedef int (*predicate_t)(void);
              predicate_t was_initscr_called = (predicate_t)PyCurses_API[2];
              if (!was_initscr_called()) {
                  return NULL;
              }
          }

 -- C Macro: PyCursesInitialisedColor

     Macro checking if *note curses.start_color(): 319e. has been
     called.

     The macro expansion is roughly equivalent to:

          {
              typedef int (*predicate_t)(void);
              predicate_t was_start_color_called = (predicate_t)PyCurses_API[3];
              if (!was_start_color_called()) {
                  return NULL;
              }
          }


File: python.info,  Node: Internal data,  Next: DateTime Objects<2>,  Prev: Curses C API,  Up: C API for extension modules

7.8.7.2 Internal data
.....................

The following objects are exposed by the C API but should be considered
internal-only.

 -- C Macro: PyCurses_CAPSULE_NAME

     Name of the curses capsule to pass to *note PyCapsule_Import():
     19b4.

     Internal usage only.  Use *note import_curses: 516d. instead.


File: python.info,  Node: DateTime Objects<2>,  Next: Internal data<2>,  Prev: Internal data,  Up: C API for extension modules

7.8.7.3 DateTime Objects
........................

Various date and time objects are supplied by the *note datetime: 30.
module.  Before using any of these functions, the header file
‘datetime.h’ must be included in your source (note that this is not
included by ‘Python.h’), and the macro *note PyDateTime_IMPORT: 517a.
must be invoked, usually as part of the module initialisation function.
The macro puts a pointer to a C structure into a static variable, *note
PyDateTimeAPI: 517b, that is used by the following macros.

 -- C Macro: PyDateTime_IMPORT ()

     Import the datetime C API.

     On success, populate the *note PyDateTimeAPI: 517b. pointer.  On
     failure, set ‘PyDateTimeAPI’ to ‘NULL’ and set an exception.  The
     caller must check if an error occurred via *note PyErr_Occurred():
     1a55.:

          PyDateTime_IMPORT;
          if (PyErr_Occurred()) { /* cleanup */ }

          Warning: This is not compatible with subinterpreters.

 -- C Type: type PyDateTime_CAPI

     Structure containing the fields for the datetime C API.

     The fields of this structure are private and subject to change.

     Do not use this directly; prefer ‘PyDateTime_*’ APIs instead.

 -- C Variable: *note PyDateTime_CAPI: 517c. *PyDateTimeAPI

     Dynamically allocated object containing the datetime C API.

     This variable is only available once *note PyDateTime_IMPORT: 517a.
     succeeds.

 -- C Type: type PyDateTime_Date

     This subtype of *note PyObject: 33a. represents a Python date
     object.

 -- C Type: type PyDateTime_DateTime

     This subtype of *note PyObject: 33a. represents a Python datetime
     object.

 -- C Type: type PyDateTime_Time

     This subtype of *note PyObject: 33a. represents a Python time
     object.

 -- C Type: type PyDateTime_Delta

     This subtype of *note PyObject: 33a. represents the difference
     between two datetime values.

 -- C Variable: *note PyTypeObject: aba. PyDateTime_DateType

     This instance of *note PyTypeObject: aba. represents the Python
     date type; it is the same object as *note datetime.date: 1cd. in
     the Python layer.

 -- C Variable: *note PyTypeObject: aba. PyDateTime_DateTimeType

     This instance of *note PyTypeObject: aba. represents the Python
     datetime type; it is the same object as *note datetime.datetime:
     1cc. in the Python layer.

 -- C Variable: *note PyTypeObject: aba. PyDateTime_TimeType

     This instance of *note PyTypeObject: aba. represents the Python
     time type; it is the same object as *note datetime.time: 1ce. in
     the Python layer.

 -- C Variable: *note PyTypeObject: aba. PyDateTime_DeltaType

     This instance of *note PyTypeObject: aba. represents the Python
     type for the difference between two datetime values; it is the same
     object as *note datetime.timedelta: 9da. in the Python layer.

 -- C Variable: *note PyTypeObject: aba. PyDateTime_TZInfoType

     This instance of *note PyTypeObject: aba. represents the Python
     time zone info type; it is the same object as *note
     datetime.tzinfo: 5e1. in the Python layer.

Macro for access to the UTC singleton:

 -- C Variable: *note PyObject: 33a. *PyDateTime_TimeZone_UTC

     Returns the time zone singleton representing UTC, the same object
     as *note datetime.timezone.utc: 617.

     Added in version 3.7.

Type-check macros:

 -- C Function: int PyDate_Check (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DateType: 5181. or
     a subtype of ‘PyDateTime_DateType’.  'ob' must not be ‘NULL’.  This
     function always succeeds.

 -- C Function: int PyDate_CheckExact (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DateType: 5181.
     'ob' must not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyDateTime_Check (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DateTimeType: 5182.
     or a subtype of ‘PyDateTime_DateTimeType’.  'ob' must not be
     ‘NULL’.  This function always succeeds.

 -- C Function: int PyDateTime_CheckExact (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DateTimeType: 5182.
     'ob' must not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyTime_Check (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_TimeType: 5183. or
     a subtype of ‘PyDateTime_TimeType’.  'ob' must not be ‘NULL’.  This
     function always succeeds.

 -- C Function: int PyTime_CheckExact (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_TimeType: 5183.
     'ob' must not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyDelta_Check (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DeltaType: 5184. or
     a subtype of ‘PyDateTime_DeltaType’.  'ob' must not be ‘NULL’.
     This function always succeeds.

 -- C Function: int PyDelta_CheckExact (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_DeltaType: 5184.
     'ob' must not be ‘NULL’.  This function always succeeds.

 -- C Function: int PyTZInfo_Check (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_TZInfoType: 5185.
     or a subtype of ‘PyDateTime_TZInfoType’.  'ob' must not be ‘NULL’.
     This function always succeeds.

 -- C Function: int PyTZInfo_CheckExact (PyObject *ob)

     Return true if 'ob' is of type *note PyDateTime_TZInfoType: 5185.
     'ob' must not be ‘NULL’.  This function always succeeds.

Macros to create objects:

 -- C Function: *note PyObject: 33a. *PyDate_FromDate (int year, int
          month, int day)
     'Return value: New reference.'  Return a *note datetime.date: 1cd.
     object with the specified year, month and day.

 -- C Function: *note PyObject: 33a. *PyDateTime_FromDateAndTime (int
          year, int month, int day, int hour, int minute, int second,
          int usecond)
     'Return value: New reference.'  Return a *note datetime.datetime:
     1cc. object with the specified year, month, day, hour, minute,
     second and microsecond.

 -- C Function: *note PyObject: 33a. *PyDateTime_FromDateAndTimeAndFold
          (int year, int month, int day, int hour, int minute, int
          second, int usecond, int fold)
     'Return value: New reference.'  Return a *note datetime.datetime:
     1cc. object with the specified year, month, day, hour, minute,
     second, microsecond and fold.

     Added in version 3.6.

 -- C Function: *note PyObject: 33a. *PyTime_FromTime (int hour, int
          minute, int second, int usecond)
     'Return value: New reference.'  Return a *note datetime.time: 1ce.
     object with the specified hour, minute, second and microsecond.

 -- C Function: *note PyObject: 33a. *PyTime_FromTimeAndFold (int hour,
          int minute, int second, int usecond, int fold)
     'Return value: New reference.'  Return a *note datetime.time: 1ce.
     object with the specified hour, minute, second, microsecond and
     fold.

     Added in version 3.6.

 -- C Function: *note PyObject: 33a. *PyDelta_FromDSU (int days, int
          seconds, int useconds)
     'Return value: New reference.'  Return a *note datetime.timedelta:
     9da. object representing the given number of days, seconds and
     microseconds.  Normalization is performed so that the resulting
     number of microseconds and seconds lie in the ranges documented for
     ‘datetime.timedelta’ objects.

 -- C Function: *note PyObject: 33a. *PyTimeZone_FromOffset (PyObject
          *offset)
     'Return value: New reference.'  Return a *note datetime.timezone:
     1103. object with an unnamed fixed offset represented by the
     'offset' argument.

     Added in version 3.7.

 -- C Function: *note PyObject: 33a. *PyTimeZone_FromOffsetAndName
          (PyObject *offset, PyObject *name)
     'Return value: New reference.'  Return a *note datetime.timezone:
     1103. object with a fixed offset represented by the 'offset'
     argument and with tzname 'name'.

     Added in version 3.7.

Macros to extract fields from date objects.  The argument must be an
instance of *note PyDateTime_Date: 517d, including subclasses (such as
*note PyDateTime_DateTime: 517e.).  The argument must not be ‘NULL’, and
the type is not checked:

 -- C Function: int PyDateTime_GET_YEAR (PyDateTime_Date *o)

     Return the year, as a positive int.

 -- C Function: int PyDateTime_GET_MONTH (PyDateTime_Date *o)

     Return the month, as an int from 1 through 12.

 -- C Function: int PyDateTime_GET_DAY (PyDateTime_Date *o)

     Return the day, as an int from 1 through 31.

Macros to extract fields from datetime objects.  The argument must be an
instance of *note PyDateTime_DateTime: 517e, including subclasses.  The
argument must not be ‘NULL’, and the type is not checked:

 -- C Function: int PyDateTime_DATE_GET_HOUR (PyDateTime_DateTime *o)

     Return the hour, as an int from 0 through 23.

 -- C Function: int PyDateTime_DATE_GET_MINUTE (PyDateTime_DateTime *o)

     Return the minute, as an int from 0 through 59.

 -- C Function: int PyDateTime_DATE_GET_SECOND (PyDateTime_DateTime *o)

     Return the second, as an int from 0 through 59.

 -- C Function: int PyDateTime_DATE_GET_MICROSECOND (PyDateTime_DateTime
          *o)

     Return the microsecond, as an int from 0 through 999999.

 -- C Function: int PyDateTime_DATE_GET_FOLD (PyDateTime_DateTime *o)

     Return the fold, as an int from 0 through 1.

     Added in version 3.6.

 -- C Function: *note PyObject: 33a. *PyDateTime_DATE_GET_TZINFO
          (PyDateTime_DateTime *o)

     Return the tzinfo (which may be ‘None’).

     Added in version 3.10.

Macros to extract fields from time objects.  The argument must be an
instance of *note PyDateTime_Time: 517f, including subclasses.  The
argument must not be ‘NULL’, and the type is not checked:

 -- C Function: int PyDateTime_TIME_GET_HOUR (PyDateTime_Time *o)

     Return the hour, as an int from 0 through 23.

 -- C Function: int PyDateTime_TIME_GET_MINUTE (PyDateTime_Time *o)

     Return the minute, as an int from 0 through 59.

 -- C Function: int PyDateTime_TIME_GET_SECOND (PyDateTime_Time *o)

     Return the second, as an int from 0 through 59.

 -- C Function: int PyDateTime_TIME_GET_MICROSECOND (PyDateTime_Time *o)

     Return the microsecond, as an int from 0 through 999999.

 -- C Function: int PyDateTime_TIME_GET_FOLD (PyDateTime_Time *o)

     Return the fold, as an int from 0 through 1.

     Added in version 3.6.

 -- C Function: *note PyObject: 33a. *PyDateTime_TIME_GET_TZINFO
          (PyDateTime_Time *o)

     Return the tzinfo (which may be ‘None’).

     Added in version 3.10.

Macros to extract fields from time delta objects.  The argument must be
an instance of *note PyDateTime_Delta: 5180, including subclasses.  The
argument must not be ‘NULL’, and the type is not checked:

 -- C Function: int PyDateTime_DELTA_GET_DAYS (PyDateTime_Delta *o)

     Return the number of days, as an int from -999999999 to 999999999.

     Added in version 3.3.

 -- C Function: int PyDateTime_DELTA_GET_SECONDS (PyDateTime_Delta *o)

     Return the number of seconds, as an int from 0 through 86399.

     Added in version 3.3.

 -- C Function: int PyDateTime_DELTA_GET_MICROSECONDS (PyDateTime_Delta
          *o)

     Return the number of microseconds, as an int from 0 through 999999.

     Added in version 3.3.

Macros for the convenience of modules implementing the DB API:

 -- C Function: *note PyObject: 33a. *PyDateTime_FromTimestamp (PyObject
          *args)
     'Return value: New reference.'  Create and return a new *note
     datetime.datetime: 1cc. object given an argument tuple suitable for
     passing to *note datetime.datetime.fromtimestamp(): 4f0.

 -- C Function: *note PyObject: 33a. *PyDate_FromTimestamp (PyObject
          *args)
     'Return value: New reference.'  Create and return a new *note
     datetime.date: 1cd. object given an argument tuple suitable for
     passing to *note datetime.date.fromtimestamp(): bf3.


File: python.info,  Node: Internal data<2>,  Prev: DateTime Objects<2>,  Up: C API for extension modules

7.8.7.4 Internal data
.....................

The following symbols are exposed by the C API but should be considered
internal-only.

 -- C Macro: PyDateTime_CAPSULE_NAME

     Name of the datetime capsule to pass to *note PyCapsule_Import():
     19b4.

     Internal usage only.  Use *note PyDateTime_IMPORT: 517a. instead.


File: python.info,  Node: Initialization Finalization and Threads,  Next: Python Initialization Configuration,  Prev: Concrete Objects Layer,  Up: Python/C API Reference Manual

7.9 Initialization, Finalization, and Threads
=============================================

See *note Python Initialization Configuration: 3aa. for details on how
to configure the interpreter prior to initialization.

* Menu:

* Before Python Initialization::
* Global configuration variables::
* Initializing and finalizing the interpreter::
* Process-wide parameters::
* Thread State and the Global Interpreter Lock::
* Sub-interpreter support::
* Asynchronous Notifications::
* Profiling and Tracing::
* Reference tracing::
* Advanced Debugger Support::
* Thread Local Storage Support::
* Synchronization Primitives: Synchronization Primitives<2>.
* Operating System Thread APIs::


File: python.info,  Node: Before Python Initialization,  Next: Global configuration variables,  Up: Initialization Finalization and Threads

7.9.1 Before Python Initialization
----------------------------------

In an application embedding Python, the *note Py_Initialize(): 8b4.
function must be called before using any other Python/C API functions;
with the exception of a few functions and the *note global configuration
variables: 51ae.

The following functions can be safely called before Python is
initialized:

   * Functions that initialize the interpreter:

        * *note Py_Initialize(): 8b4.

        * *note Py_InitializeEx(): 4df3.

        * *note Py_InitializeFromConfig(): 3c8.

        * *note Py_BytesMain(): 9cc.

        * *note Py_Main(): c45.

        * the runtime pre-initialization functions covered in *note
          Python Initialization Configuration: 3aa.

   * Configuration functions:

        * *note PyImport_AppendInittab(): 18bf.

        * *note PyImport_ExtendInittab(): 18c0.

        * ‘PyInitFrozenExtensions()’

        * *note PyMem_SetAllocator(): 58e.

        * *note PyMem_SetupDebugHooks(): c8b.

        * *note PyObject_SetArenaAllocator(): 51af.

        * *note Py_SetProgramName(): 1749.

        * *note Py_SetPythonHome(): 1748.

        * *note PySys_ResetWarnOptions(): 3b2.

        * the configuration functions covered in *note Python
          Initialization Configuration: 3aa.

   * Informative functions:

        * *note Py_IsInitialized(): 4c13.

        * *note PyMem_GetAllocator(): 51b0.

        * *note PyObject_GetArenaAllocator(): 51b1.

        * *note Py_GetBuildInfo(): 1480.

        * *note Py_GetCompiler(): 4ded.

        * *note Py_GetCopyright(): 4dee.

        * *note Py_GetPlatform(): 4def.

        * *note Py_GetVersion(): 4df1.

        * *note Py_IsInitialized(): 4c13.

   * Utilities:

        * *note Py_DecodeLocale(): be6.

        * the status reporting and utility functions covered in *note
          Python Initialization Configuration: 3aa.

   * Memory allocators:

        * *note PyMem_RawMalloc(): 393.

        * *note PyMem_RawRealloc(): 395.

        * *note PyMem_RawCalloc(): 394.

        * *note PyMem_RawFree(): 396.

   * Synchronization:

        * *note PyMutex_Lock(): 32b.

        * *note PyMutex_Unlock(): 32c.

     Note: Despite their apparent similarity to some of the functions
     listed above, the following functions 'should not be called' before
     the interpreter has been initialized: *note Py_EncodeLocale(): be7,
     *note Py_GetPath(): 3b6, *note Py_GetPrefix(): 3b8, *note
     Py_GetExecPrefix(): 3b4, *note Py_GetProgramFullPath(): 3ba, *note
     Py_GetPythonHome(): 3bd, *note Py_GetProgramName(): 3bc, *note
     PyEval_InitThreads(): 174c, and *note Py_RunMain(): 9d0.


File: python.info,  Node: Global configuration variables,  Next: Initializing and finalizing the interpreter,  Prev: Before Python Initialization,  Up: Initialization Finalization and Threads

7.9.2 Global configuration variables
------------------------------------

Python has variables for the global configuration to control different
features and options.  By default, these flags are controlled by *note
command line options: 1ed2.

When a flag is set by an option, the value of the flag is the number of
times that the option was set.  For example, ‘-b’ sets *note
Py_BytesWarningFlag: 3d7. to 1 and ‘-bb’ sets ‘Py_BytesWarningFlag’ to
2.

 -- C Variable: int Py_BytesWarningFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.bytes_warning: 3d8. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     Issue a warning when comparing *note bytes: 1c2. or *note
     bytearray: 2ea. with *note str: 44f. or ‘bytes’ with *note int:
     257.  Issue an error if greater or equal to ‘2’.

     Set by the *note -b: 5e6. option.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_DebugFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.parser_debug: 3ca. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     Turn on parser debugging output (for expert only, depending on
     compilation options).

     Set by the *note -d: 1eda. option and the *note PYTHONDEBUG: 1edb.
     environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_DontWriteBytecodeFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.write_bytecode: 3de. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     If set to non-zero, Python won’t try to write ‘.pyc’ files on the
     import of source modules.

     Set by the *note -B: 141b. option and the *note
     PYTHONDONTWRITEBYTECODE: 141c. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_FrozenFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.pathconfig_warnings: 3da. should be used instead, see
     *note Python Initialization Configuration: 3aa.

     Suppress error messages when calculating the module search path in
     *note Py_GetPath(): 3b6.

     Private flag used by ‘_freeze_module’ and ‘frozenmain’ programs.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_HashRandomizationFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.hash_seed: 3e5. and *note PyConfig.use_hash_seed: 3e4.
     should be used instead, see *note Python Initialization
     Configuration: 3aa.

     Set to ‘1’ if the *note PYTHONHASHSEED: 10bb. environment variable
     is set to a non-empty string.

     If the flag is non-zero, read the *note PYTHONHASHSEED: 10bb.
     environment variable to initialize the secret hash seed.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_IgnoreEnvironmentFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.use_environment: 3dc. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     Ignore all ‘PYTHON*’ environment variables, e.g.  *note PYTHONPATH:
     1058. and *note PYTHONHOME: 3bf, that might be set.

     Set by the *note -E: 967. and *note -I: 968. options.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_InspectFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.inspect: 3d2. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     When a script is passed as first argument or the *note -c: 5e3.
     option is used, enter interactive mode after executing the script
     or the command, even when *note sys.stdin: 540. does not appear to
     be a terminal.

     Set by the *note -i: 152a. option and the *note PYTHONINSPECT:
     1529. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_InteractiveFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.interactive: 3d0. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Set by the *note -i: 152a. option.

     Deprecated since version 3.12, will be removed in version 3.15.

 -- C Variable: int Py_IsolatedFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.isolated: 3e7. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Run Python in isolated mode.  In isolated mode *note sys.path: 3b7.
     contains neither the script’s directory nor the user’s
     site-packages directory.

     Set by the *note -I: 968. option.

     Added in version 3.4.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_LegacyWindowsFSEncodingFlag

     This API is kept for backward compatibility: setting *note
     PyPreConfig.legacy_windows_fs_encoding: 3e9. should be used
     instead, see *note Python Initialization Configuration: 3aa.

     If the flag is non-zero, use the ‘mbcs’ encoding with ‘replace’
     error handler, instead of the UTF-8 encoding with ‘surrogatepass’
     error handler, for the *note filesystem encoding and error handler:
     53e.

     Set to ‘1’ if the *note PYTHONLEGACYWINDOWSFSENCODING: 2af.
     environment variable is set to a non-empty string.

     See PEP 529(1) for more details.

     *note Availability: 1ef7.: Windows.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_LegacyWindowsStdioFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.legacy_windows_stdio: 3a7. should be used instead, see
     *note Python Initialization Configuration: 3aa.

     If the flag is non-zero, use *note io.FileIO: 1359. instead of
     ‘io._WindowsConsoleIO’ for *note sys: d9. standard streams.

     Set to ‘1’ if the *note PYTHONLEGACYWINDOWSSTDIO: c7c. environment
     variable is set to a non-empty string.

     See PEP 528(2) for more details.

     *note Availability: 1ef7.: Windows.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_NoSiteFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.site_import: 3d6. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Disable the import of the module *note site: c7. and the
     site-dependent manipulations of *note sys.path: 3b7. that it
     entails.  Also disable these manipulations if ‘site’ is explicitly
     imported later (call *note site.main(): 1ede. if you want them to
     be triggered).

     Set by the *note -S: 11ec. option.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_NoUserSiteDirectory

     This API is kept for backward compatibility: setting *note
     PyConfig.user_site_directory: 3e0. should be used instead, see
     *note Python Initialization Configuration: 3aa.

     Don’t add the *note user site-packages directory: 1edd. to *note
     sys.path: 3b7.

     Set by the *note -s: 13db. and *note -I: 968. options, and the
     *note PYTHONNOUSERSITE: 13dc. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_OptimizeFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.optimization_level: 3d4. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     Set by the *note -O: de3. option and the *note PYTHONOPTIMIZE:
     1edc. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_QuietFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.quiet: 3ce. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Don’t display the copyright and version messages even in
     interactive mode.

     Set by the *note -q: 15c9. option.

     Added in version 3.2.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_UnbufferedStdioFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.buffered_stdio: 3e2. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     Force the stdout and stderr streams to be unbuffered.

     Set by the *note -u: 1b36. option and the *note PYTHONUNBUFFERED:
     1b37. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

 -- C Variable: int Py_VerboseFlag

     This API is kept for backward compatibility: setting *note
     PyConfig.verbose: 3cc. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Print a message each time a module is initialized, showing the
     place (filename or built-in module) from which it is loaded.  If
     greater or equal to ‘2’, print a message for each file that is
     checked for when searching for a module.  Also provides information
     on module cleanup at exit.

     Set by the *note -v: 1473. option and the *note PYTHONVERBOSE:
     1edf. environment variable.

     Deprecated since version 3.12, will be removed in version 3.14.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0529/

   (2) https://peps.python.org/pep-0528/


File: python.info,  Node: Initializing and finalizing the interpreter,  Next: Process-wide parameters,  Prev: Global configuration variables,  Up: Initialization Finalization and Threads

7.9.3 Initializing and finalizing the interpreter
-------------------------------------------------

 -- C Function: void Py_Initialize ()
     ' Part of the *note Stable ABI: 556.'

     Initialize the Python interpreter.  In an application embedding
     Python, this should be called before using any other Python/C API
     functions; see *note Before Python Initialization: be4. for the few
     exceptions.

     This initializes the table of loaded modules (‘sys.modules’), and
     creates the fundamental modules *note builtins: 12, *note __main__:
     1. and *note sys: d9.  It also initializes the module search path
     (‘sys.path’).  It does not set ‘sys.argv’; use the *note Python
     Initialization Configuration: 3aa. API for that.  This is a no-op
     when called for a second time (without calling *note
     Py_FinalizeEx(): d3d. first).  There is no return value; it is a
     fatal error if the initialization fails.

     Use *note Py_InitializeFromConfig(): 3c8. to customize the *note
     Python Initialization Configuration: 3aa.

          Note: On Windows, changes the console mode from ‘O_TEXT’ to
          ‘O_BINARY’, which will also affect non-Python uses of the
          console using the C Runtime.

 -- C Function: void Py_InitializeEx (int initsigs)
     ' Part of the *note Stable ABI: 556.'  This function works like
     *note Py_Initialize(): 8b4. if 'initsigs' is ‘1’.  If 'initsigs' is
     ‘0’, it skips initialization registration of signal handlers, which
     may be useful when CPython is embedded as part of a larger
     application.

     Use *note Py_InitializeFromConfig(): 3c8. to customize the *note
     Python Initialization Configuration: 3aa.

 -- C Function: *note PyStatus: 9b8. Py_InitializeFromConfig (const
          PyConfig *config)

     Initialize Python from 'config' configuration, as described in
     *note Initialization with PyConfig: 51b4.

     See the *note Python Initialization Configuration: 3aa. section for
     details on pre-initializing the interpreter, populating the runtime
     configuration structure, and querying the returned status
     structure.

 -- C Function: int Py_IsInitialized ()
     ' Part of the *note Stable ABI: 556.'  Return true (nonzero) when
     the Python interpreter has been initialized, false (zero) if not.
     After *note Py_FinalizeEx(): d3d. is called, this returns false
     until *note Py_Initialize(): 8b4. is called again.

 -- C Function: int Py_IsFinalizing ()
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Return
     true (non-zero) if the main Python interpreter is *note shutting
     down: 14e.  Return false (zero) otherwise.

     Added in version 3.13.

 -- C Function: int Py_FinalizeEx ()
     ' Part of the *note Stable ABI: 556. since version 3.6.'  Undo all
     initializations made by *note Py_Initialize(): 8b4. and subsequent
     use of Python/C API functions, and destroy all sub-interpreters
     (see *note Py_NewInterpreter(): 18d4. below) that were created and
     not yet destroyed since the last call to ‘Py_Initialize()’.
     Ideally, this frees all memory allocated by the Python interpreter.
     This is a no-op when called for a second time (without calling
     ‘Py_Initialize()’ again first).

     Since this is the reverse of *note Py_Initialize(): 8b4, it should
     be called in the same thread with the same interpreter active.
     That means the main thread and the main interpreter.  This should
     never be called while *note Py_RunMain(): 9d0. is running.

     Normally the return value is ‘0’.  If there were errors during
     finalization (flushing buffered data), ‘-1’ is returned.

     This function is provided for a number of reasons.  An embedding
     application might want to restart Python without having to restart
     the application itself.  An application that has loaded the Python
     interpreter from a dynamically loadable library (or DLL) might want
     to free all memory allocated by Python before unloading the DLL.
     During a hunt for memory leaks in an application a developer might
     want to free all memory allocated by Python before exiting from the
     application.

     'Bugs and caveats:' The destruction of modules and objects in
     modules is done in random order; this may cause destructors (*note
     __del__(): 1038. methods) to fail when they depend on other objects
     (even functions) or modules.  Dynamically loaded extension modules
     loaded by Python are not unloaded.  Small amounts of memory
     allocated by the Python interpreter may not be freed (if you find a
     leak, please report it).  Memory tied up in circular references
     between objects is not freed.  Some memory allocated by extension
     modules may not be freed.  Some extensions may not work properly if
     their initialization routine is called more than once; this can
     happen if an application calls *note Py_Initialize(): 8b4. and
     *note Py_FinalizeEx(): d3d. more than once.  ‘Py_FinalizeEx()’ must
     not be called recursively from within itself.  Therefore, it must
     not be called by any code that may be run as part of the
     interpreter shutdown process, such as *note atexit: c. handlers,
     object finalizers, or any code that may be run while flushing the
     stdout and stderr files.

     Raises an *note auditing event: 1a15.
     ‘cpython._PySys_ClearAuditHooks’ with no arguments.

     Added in version 3.6.

 -- C Function: void Py_Finalize ()
     ' Part of the *note Stable ABI: 556.'  This is a
     backwards-compatible version of *note Py_FinalizeEx(): d3d. that
     disregards the return value.

 -- C Function: int Py_BytesMain (int argc, char **argv)
     ' Part of the *note Stable ABI: 556. since version 3.8.'  Similar
     to *note Py_Main(): c45. but 'argv' is an array of bytes strings,
     allowing the calling application to delegate the text decoding step
     to the CPython runtime.

     Added in version 3.8.

 -- C Function: int Py_Main (int argc, wchar_t **argv)
     ' Part of the *note Stable ABI: 556.'  The main program for the
     standard interpreter, encapsulating a full
     initialization/finalization cycle, as well as additional behaviour
     to implement reading configurations settings from the environment
     and command line, and then executing ‘__main__’ in accordance with
     *note Command line: 1042.

     This is made available for programs which wish to support the full
     CPython command line interface, rather than just embedding a Python
     runtime in a larger application.

     The 'argc' and 'argv' parameters are similar to those which are
     passed to a C program’s ‘main()’ function, except that the 'argv'
     entries are first converted to ‘wchar_t’ using *note
     Py_DecodeLocale(): be6.  It is also important to note that the
     argument list entries may be modified to point to strings other
     than those passed in (however, the contents of the strings pointed
     to by the argument list are not modified).

     The return value is ‘2’ if the argument list does not represent a
     valid Python command line, and otherwise the same as *note
     Py_RunMain(): 9d0.

     In terms of the CPython runtime configuration APIs documented in
     the *note runtime configuration: 3aa. section (and without
     accounting for error handling), ‘Py_Main’ is approximately
     equivalent to:

          PyConfig config;
          PyConfig_InitPythonConfig(&config);
          PyConfig_SetArgv(&config, argc, argv);
          Py_InitializeFromConfig(&config);
          PyConfig_Clear(&config);

          Py_RunMain();

     In normal usage, an embedding application will call this function
     'instead' of calling *note Py_Initialize(): 8b4, *note
     Py_InitializeEx(): 4df3. or *note Py_InitializeFromConfig(): 3c8.
     directly, and all settings will be applied as described elsewhere
     in this documentation.  If this function is instead called 'after'
     a preceding runtime initialization API call, then exactly which
     environmental and command line configuration settings will be
     updated is version dependent (as it depends on which settings
     correctly support being modified after they have already been set
     once when the runtime was first initialized).

 -- C Function: int Py_RunMain (void)

     Executes the main module in a fully configured CPython runtime.

     Executes the command (*note PyConfig.run_command: 51b5.), the
     script (*note PyConfig.run_filename: 51b6.) or the module (*note
     PyConfig.run_module: 51b7.) specified on the command line or in the
     configuration.  If none of these values are set, runs the
     interactive Python prompt (REPL) using the ‘__main__’ module’s
     global namespace.

     If *note PyConfig.inspect: 3d2. is not set (the default), the
     return value will be ‘0’ if the interpreter exits normally (that
     is, without raising an exception), the exit status of an unhandled
     *note SystemExit: d69, or ‘1’ for any other unhandled exception.

     If *note PyConfig.inspect: 3d2. is set (such as when the *note -i:
     152a. option is used), rather than returning when the interpreter
     exits, execution will instead resume in an interactive Python
     prompt (REPL) using the ‘__main__’ module’s global namespace.  If
     the interpreter exited with an exception, it is immediately raised
     in the REPL session.  The function return value is then determined
     by the way the 'REPL session' terminates: ‘0’, ‘1’, or the status
     of a *note SystemExit: d69, as specified above.

     This function always finalizes the Python interpreter before it
     returns.

     See *note Python Configuration: 51b8. for an example of a
     customized Python that always runs in isolated mode using *note
     Py_RunMain(): 9d0.

 -- C Function: int PyUnstable_AtExit (PyInterpreterState *interp, void
          (*func)(void*), void *data)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Register an *note atexit: c. callback for the target interpreter
     'interp'.  This is similar to *note Py_AtExit(): 4de8, but takes an
     explicit interpreter and data pointer for the callback.

     The *note GIL: 159. must be held for 'interp'.

     Added in version 3.13.


File: python.info,  Node: Process-wide parameters,  Next: Thread State and the Global Interpreter Lock,  Prev: Initializing and finalizing the interpreter,  Up: Initialization Finalization and Threads

7.9.4 Process-wide parameters
-----------------------------

 -- C Function: void Py_SetProgramName (const wchar_t *name)
     ' Part of the *note Stable ABI: 556.'

     This API is kept for backward compatibility: setting *note
     PyConfig.program_name: 3c7. should be used instead, see *note
     Python Initialization Configuration: 3aa.

     This function should be called before *note Py_Initialize(): 8b4.
     is called for the first time, if it is called at all.  It tells the
     interpreter the value of the ‘argv[0]’ argument to the ‘main()’
     function of the program (converted to wide characters).  This is
     used by *note Py_GetPath(): 3b6. and some other functions below to
     find the Python run-time libraries relative to the interpreter
     executable.  The default value is ‘'python'’.  The argument should
     point to a zero-terminated wide character string in static storage
     whose contents will not change for the duration of the program’s
     execution.  No code in the Python interpreter will change the
     contents of this storage.

     Use *note Py_DecodeLocale(): be6. to decode a bytes string to get a
     wchar_t* string.

     Deprecated since version 3.11.

 -- C Function: wchar_t *Py_GetProgramName ()
     ' Part of the *note Stable ABI: 556.'  Return the program name set
     with *note PyConfig.program_name: 3c7, or the default.  The
     returned string points into static storage; the caller should not
     modify its value.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note sys.executable: 3bb. instead.

 -- C Function: wchar_t *Py_GetPrefix ()
     ' Part of the *note Stable ABI: 556.'  Return the 'prefix' for
     installed platform-independent files.  This is derived through a
     number of complicated rules from the program name set with *note
     PyConfig.program_name: 3c7. and some environment variables; for
     example, if the program name is ‘'/usr/local/bin/python'’, the
     prefix is ‘'/usr/local'’.  The returned string points into static
     storage; the caller should not modify its value.  This corresponds
     to the ‘prefix’ variable in the top-level ‘Makefile’ and the *note
     -prefix: 1f06. argument to the ‘configure’ script at build time.
     The value is available to Python code as ‘sys.base_prefix’.  It is
     only useful on Unix.  See also the next function.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note sys.base_prefix: 3f2. instead, or *note sys.prefix: 3b9. if
     *note virtual environments: 4579. need to be handled.

 -- C Function: wchar_t *Py_GetExecPrefix ()
     ' Part of the *note Stable ABI: 556.'  Return the 'exec-prefix' for
     installed platform-'dependent' files.  This is derived through a
     number of complicated rules from the program name set with *note
     PyConfig.program_name: 3c7. and some environment variables; for
     example, if the program name is ‘'/usr/local/bin/python'’, the
     exec-prefix is ‘'/usr/local'’.  The returned string points into
     static storage; the caller should not modify its value.  This
     corresponds to the ‘exec_prefix’ variable in the top-level
     ‘Makefile’ and the ‘--exec-prefix’ argument to the ‘configure’
     script at build time.  The value is available to Python code as
     ‘sys.base_exec_prefix’.  It is only useful on Unix.

     Background: The exec-prefix differs from the prefix when platform
     dependent files (such as executables and shared libraries) are
     installed in a different directory tree.  In a typical
     installation, platform dependent files may be installed in the
     ‘/usr/local/plat’ subtree while platform independent may be
     installed in ‘/usr/local’.

     Generally speaking, a platform is a combination of hardware and
     software families, e.g.  Sparc machines running the Solaris 2.x
     operating system are considered the same platform, but Intel
     machines running Solaris 2.x are another platform, and Intel
     machines running Linux are yet another platform.  Different major
     revisions of the same operating system generally also form
     different platforms.  Non-Unix operating systems are a different
     story; the installation strategies on those systems are so
     different that the prefix and exec-prefix are meaningless, and set
     to the empty string.  Note that compiled Python bytecode files are
     platform independent (but not independent from the Python version
     by which they were compiled!).

     System administrators will know how to configure the ‘mount’ or
     ‘automount’ programs to share ‘/usr/local’ between platforms while
     having ‘/usr/local/plat’ be a different filesystem for each
     platform.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note sys.base_exec_prefix: 3f1. instead, or *note sys.exec_prefix:
     3b5. if *note virtual environments: 4579. need to be handled.

 -- C Function: wchar_t *Py_GetProgramFullPath ()
     ' Part of the *note Stable ABI: 556.'

     Return the full program name of the Python executable; this is
     computed as a side-effect of deriving the default module search
     path from the program name (set by *note PyConfig.program_name:
     3c7.).  The returned string points into static storage; the caller
     should not modify its value.  The value is available to Python code
     as ‘sys.executable’.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note sys.executable: 3bb. instead.

 -- C Function: wchar_t *Py_GetPath ()
     ' Part of the *note Stable ABI: 556.'

     Return the default module search path; this is computed from the
     program name (set by *note PyConfig.program_name: 3c7.) and some
     environment variables.  The returned string consists of a series of
     directory names separated by a platform dependent delimiter
     character.  The delimiter character is ‘':'’ on Unix and macOS,
     ‘';'’ on Windows.  The returned string points into static storage;
     the caller should not modify its value.  The list *note sys.path:
     3b7. is initialized with this value on interpreter startup; it can
     be (and usually is) modified later to change the search path for
     loading modules.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note sys.path: 3b7. instead.

 -- C Function: const char *Py_GetVersion ()
     ' Part of the *note Stable ABI: 556.'  Return the version of this
     Python interpreter.  This is a string that looks something like

          "3.0a5+ (py3k:63103M, May 12 2008, 00:53:55) \n[GCC 4.2.3]"

     The first word (up to the first space character) is the current
     Python version; the first characters are the major and minor
     version separated by a period.  The returned string points into
     static storage; the caller should not modify its value.  The value
     is available to Python code as *note sys.version: 178.

     See also the *note Py_Version: 759. constant.

 -- C Function: const char *Py_GetPlatform ()
     ' Part of the *note Stable ABI: 556.'

     Return the platform identifier for the current platform.  On Unix,
     this is formed from the “official” name of the operating system,
     converted to lower case, followed by the major revision number;
     e.g., for Solaris 2.x, which is also known as SunOS 5.x, the value
     is ‘'sunos5'’.  On macOS, it is ‘'darwin'’.  On Windows, it is
     ‘'win'’.  The returned string points into static storage; the
     caller should not modify its value.  The value is available to
     Python code as ‘sys.platform’.

 -- C Function: const char *Py_GetCopyright ()
     ' Part of the *note Stable ABI: 556.'  Return the official
     copyright string for the current Python version, for example

     ‘'Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam'’

     The returned string points into static storage; the caller should
     not modify its value.  The value is available to Python code as
     ‘sys.copyright’.

 -- C Function: const char *Py_GetCompiler ()
     ' Part of the *note Stable ABI: 556.'  Return an indication of the
     compiler used to build the current Python version, in square
     brackets, for example:

          "[GCC 2.7.2.2]"

     The returned string points into static storage; the caller should
     not modify its value.  The value is available to Python code as
     part of the variable ‘sys.version’.

 -- C Function: const char *Py_GetBuildInfo ()
     ' Part of the *note Stable ABI: 556.'  Return information about the
     sequence number and build date and time of the current Python
     interpreter instance, for example

          "#67, Aug  1 1997, 22:34:28"

     The returned string points into static storage; the caller should
     not modify its value.  The value is available to Python code as
     part of the variable ‘sys.version’.

 -- C Function: void PySys_SetArgvEx (int argc, wchar_t **argv, int
          updatepath)
     ' Part of the *note Stable ABI: 556.'

     This API is kept for backward compatibility: setting *note
     PyConfig.argv: 3c6, *note PyConfig.parse_argv: 1a98. and *note
     PyConfig.safe_path: 776. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     Set *note sys.argv: 12ab. based on 'argc' and 'argv'.  These
     parameters are similar to those passed to the program’s ‘main()’
     function with the difference that the first entry should refer to
     the script file to be executed rather than the executable hosting
     the Python interpreter.  If there isn’t a script that will be run,
     the first entry in 'argv' can be an empty string.  If this function
     fails to initialize ‘sys.argv’, a fatal condition is signalled
     using *note Py_FatalError(): 98d.

     If 'updatepath' is zero, this is all the function does.  If
     'updatepath' is non-zero, the function also modifies *note
     sys.path: 3b7. according to the following algorithm:

        - If the name of an existing script is passed in ‘argv[0]’, the
          absolute path of the directory where the script is located is
          prepended to *note sys.path: 3b7.

        - Otherwise (that is, if 'argc' is ‘0’ or ‘argv[0]’ doesn’t
          point to an existing file name), an empty string is prepended
          to *note sys.path: 3b7, which is the same as prepending the
          current working directory (‘"."’).

     Use *note Py_DecodeLocale(): be6. to decode a bytes string to get a
     wchar_t* string.

     See also *note PyConfig.orig_argv: 89b. and *note PyConfig.argv:
     3c6. members of the *note Python Initialization Configuration: 3aa.

          Note: It is recommended that applications embedding the Python
          interpreter for purposes other than executing a single script
          pass ‘0’ as 'updatepath', and update *note sys.path: 3b7.
          themselves if desired.  See CVE 2008-5983(1).

          On versions before 3.1.3, you can achieve the same effect by
          manually popping the first *note sys.path: 3b7. element after
          having called *note PySys_SetArgv(): 174b, for example using:

               PyRun_SimpleString("import sys; sys.path.pop(0)\n");

     Added in version 3.1.3.

     Deprecated since version 3.11.

 -- C Function: void PySys_SetArgv (int argc, wchar_t **argv)
     ' Part of the *note Stable ABI: 556.'  This API is kept for
     backward compatibility: setting *note PyConfig.argv: 3c6. and *note
     PyConfig.parse_argv: 1a98. should be used instead, see *note Python
     Initialization Configuration: 3aa.

     This function works like *note PySys_SetArgvEx(): 174a. with
     'updatepath' set to ‘1’ unless the ‘python’ interpreter was started
     with the *note -I: 968.

     Use *note Py_DecodeLocale(): be6. to decode a bytes string to get a
     wchar_t* string.

     See also *note PyConfig.orig_argv: 89b. and *note PyConfig.argv:
     3c6. members of the *note Python Initialization Configuration: 3aa.

     Changed in version 3.4: The 'updatepath' value depends on *note -I:
     968.

     Deprecated since version 3.11.

 -- C Function: void Py_SetPythonHome (const wchar_t *home)
     ' Part of the *note Stable ABI: 556.'  This API is kept for
     backward compatibility: setting *note PyConfig.home: 3be. should be
     used instead, see *note Python Initialization Configuration: 3aa.

     Set the default “home” directory, that is, the location of the
     standard Python libraries.  See *note PYTHONHOME: 3bf. for the
     meaning of the argument string.

     The argument should point to a zero-terminated character string in
     static storage whose contents will not change for the duration of
     the program’s execution.  No code in the Python interpreter will
     change the contents of this storage.

     Use *note Py_DecodeLocale(): be6. to decode a bytes string to get a
     wchar_t* string.

     Deprecated since version 3.11.

 -- C Function: wchar_t *Py_GetPythonHome ()
     ' Part of the *note Stable ABI: 556.'  Return the default “home”,
     that is, the value set by *note PyConfig.home: 3be, or the value of
     the *note PYTHONHOME: 3bf. environment variable if it is set.

     This function should not be called before *note Py_Initialize():
     8b4, otherwise it returns ‘NULL’.

     Changed in version 3.10: It now returns ‘NULL’ if called before
     *note Py_Initialize(): 8b4.

     Deprecated since version 3.13, will be removed in version 3.15: Get
     *note PyConfig.home: 3be. or *note PYTHONHOME: 3bf. environment
     variable instead.

   ---------- Footnotes ----------

   (1) https://www.cve.org/CVERecord?id=CVE-2008-5983


File: python.info,  Node: Thread State and the Global Interpreter Lock,  Next: Sub-interpreter support,  Prev: Process-wide parameters,  Up: Initialization Finalization and Threads

7.9.5 Thread State and the Global Interpreter Lock
--------------------------------------------------

The Python interpreter is not fully thread-safe.  In order to support
multi-threaded Python programs, there’s a global lock, called the *note
global interpreter lock: 148. or *note GIL: 159, that must be held by
the current thread before it can safely access Python objects.  Without
the lock, even the simplest operations could cause problems in a
multi-threaded program: for example, when two threads simultaneously
increment the reference count of the same object, the reference count
could end up being incremented only once instead of twice.

Therefore, the rule exists that only the thread that has acquired the
*note GIL: 159. may operate on Python objects or call Python/C API
functions.  In order to emulate concurrency of execution, the
interpreter regularly tries to switch threads (see *note
sys.setswitchinterval(): 954.).  The lock is also released around
potentially blocking I/O operations like reading or writing a file, so
that other Python threads can run in the meantime.

The Python interpreter keeps some thread-specific bookkeeping
information inside a data structure called *note PyThreadState: 790.
There’s also one global variable pointing to the current
‘PyThreadState’: it can be retrieved using *note PyThreadState_Get():
375.

* Menu:

* Releasing the GIL from extension code::
* Non-Python created threads::
* Cautions about fork(): Cautions about fork.
* Cautions regarding runtime finalization::
* High-level API::
* Low-level API::


File: python.info,  Node: Releasing the GIL from extension code,  Next: Non-Python created threads,  Up: Thread State and the Global Interpreter Lock

7.9.5.1 Releasing the GIL from extension code
.............................................

Most extension code manipulating the *note GIL: 159. has the following
simple structure:

     Save the thread state in a local variable.
     Release the global interpreter lock.
     ... Do some blocking I/O operation ...
     Reacquire the global interpreter lock.
     Restore the thread state from the local variable.

This is so common that a pair of macros exists to simplify it:

     Py_BEGIN_ALLOW_THREADS
     ... Do some blocking I/O operation ...
     Py_END_ALLOW_THREADS

The *note Py_BEGIN_ALLOW_THREADS: 4b88. macro opens a new block and
declares a hidden local variable; the *note Py_END_ALLOW_THREADS: a9d.
macro closes the block.

The block above expands to the following code:

     PyThreadState *_save;

     _save = PyEval_SaveThread();
     ... Do some blocking I/O operation ...
     PyEval_RestoreThread(_save);

Here is how these functions work: the global interpreter lock is used to
protect the pointer to the current thread state.  When releasing the
lock and saving the thread state, the current thread state pointer must
be retrieved before the lock is released (since another thread could
immediately acquire the lock and store its own thread state in the
global variable).  Conversely, when acquiring the lock and restoring the
thread state, the lock must be acquired before storing the thread state
pointer.

     Note: Calling system I/O functions is the most common use case for
     releasing the GIL, but it can also be useful before calling
     long-running computations which don’t need access to Python
     objects, such as compression or cryptographic functions operating
     over memory buffers.  For example, the standard *note zlib: 133.
     and *note hashlib: 68. modules release the GIL when compressing or
     hashing data.


File: python.info,  Node: Non-Python created threads,  Next: Cautions about fork,  Prev: Releasing the GIL from extension code,  Up: Thread State and the Global Interpreter Lock

7.9.5.2 Non-Python created threads
..................................

When threads are created using the dedicated Python APIs (such as the
*note threading: ed. module), a thread state is automatically associated
to them and the code showed above is therefore correct.  However, when
threads are created from C (for example by a third-party library with
its own thread management), they don’t hold the GIL, nor is there a
thread state structure for them.

If you need to call Python code from these threads (often this will be
part of a callback API provided by the aforementioned third-party
library), you must first register these threads with the interpreter by
creating a thread state data structure, then acquiring the GIL, and
finally storing their thread state pointer, before you can start using
the Python/C API. When you are done, you should reset the thread state
pointer, release the GIL, and finally free the thread state data
structure.

The *note PyGILState_Ensure(): 3ae. and *note PyGILState_Release(): 3af.
functions do all of the above automatically.  The typical idiom for
calling into Python from a C thread is:

     PyGILState_STATE gstate;
     gstate = PyGILState_Ensure();

     /* Perform Python actions here. */
     result = CallSomeFunction();
     /* evaluate result or handle exception */

     /* Release the thread. No Python API allowed beyond this point. */
     PyGILState_Release(gstate);

Note that the ‘PyGILState_*’ functions assume there is only one global
interpreter (created automatically by *note Py_Initialize(): 8b4.).
Python supports the creation of additional interpreters (using *note
Py_NewInterpreter(): 18d4.), but mixing multiple interpreters and the
‘PyGILState_*’ API is unsupported.


File: python.info,  Node: Cautions about fork,  Next: Cautions regarding runtime finalization,  Prev: Non-Python created threads,  Up: Thread State and the Global Interpreter Lock

7.9.5.3 Cautions about fork()
.............................

Another important thing to note about threads is their behaviour in the
face of the C ‘fork()’ call.  On most systems with ‘fork()’, after a
process forks only the thread that issued the fork will exist.  This has
a concrete impact both on how locks must be handled and on all stored
state in CPython’s runtime.

The fact that only the “current” thread remains means any locks held by
other threads will never be released.  Python solves this for *note
os.fork(): 197. by acquiring the locks it uses internally before the
fork, and releasing them afterwards.  In addition, it resets any *note
Lock objects: 331c. in the child.  When extending or embedding Python,
there is no way to inform Python of additional (non-Python) locks that
need to be acquired before or reset after a fork.  OS facilities such as
‘pthread_atfork()’ would need to be used to accomplish the same thing.
Additionally, when extending or embedding Python, calling ‘fork()’
directly rather than through ‘os.fork()’ (and returning to or calling
into Python) may result in a deadlock by one of Python’s internal locks
being held by a thread that is defunct after the fork.  *note
PyOS_AfterFork_Child(): 3fe. tries to reset the necessary locks, but is
not always able to.

The fact that all other threads go away also means that CPython’s
runtime state there must be cleaned up properly, which *note os.fork():
197. does.  This means finalizing all other *note PyThreadState: 790.
objects belonging to the current interpreter and all other *note
PyInterpreterState: 8c5. objects.  Due to this and the special nature of
the *note “main” interpreter: 58a, ‘fork()’ should only be called in
that interpreter’s “main” thread, where the CPython global runtime was
originally initialized.  The only exception is if ‘exec()’ will be
called immediately after.


File: python.info,  Node: Cautions regarding runtime finalization,  Next: High-level API,  Prev: Cautions about fork,  Up: Thread State and the Global Interpreter Lock

7.9.5.4 Cautions regarding runtime finalization
...............................................

In the late stage of *note interpreter shutdown: 14e, after attempting
to wait for non-daemon threads to exit (though this can be interrupted
by *note KeyboardInterrupt: 9dc.) and running the *note atexit: c.
functions, the runtime is marked as 'finalizing': *note
Py_IsFinalizing(): 35b. and *note sys.is_finalizing(): a9e. return true.
At this point, only the 'finalization thread' that initiated
finalization (typically the main thread) is allowed to acquire the *note
GIL: 159.

If any thread, other than the finalization thread, attempts to acquire
the GIL during finalization, either explicitly via *note
PyGILState_Ensure(): 3ae, *note Py_END_ALLOW_THREADS: a9d, *note
PyEval_AcquireThread(): 3ad, or ‘PyEval_AcquireLock()’, or implicitly
when the interpreter attempts to reacquire it after having yielded it,
the thread enters 'a permanently blocked state' where it remains until
the program exits.  In most cases this is harmless, but this can result
in deadlock if a later stage of finalization attempts to acquire a lock
owned by the blocked thread, or otherwise waits on the blocked thread.

Gross?  Yes.  This prevents random crashes and/or unexpectedly skipped
C++ finalizations further up the call stack when such threads were
forcibly exited here in CPython 3.13.7 and earlier.  The CPython runtime
GIL acquiring C APIs have never had any error reporting or handling
expectations at GIL acquisition time that would’ve allowed for graceful
exit from this situation.  Changing that would require new stable C APIs
and rewriting the majority of C code in the CPython ecosystem to use
those with error handling.


File: python.info,  Node: High-level API,  Next: Low-level API,  Prev: Cautions regarding runtime finalization,  Up: Thread State and the Global Interpreter Lock

7.9.5.5 High-level API
......................

These are the most commonly used types and functions when writing C
extension code, or when embedding the Python interpreter:

 -- C Type: type PyInterpreterState
     ' Part of the *note Limited API: 556. (as an opaque struct).'  This
     data structure represents the state shared by a number of
     cooperating threads.  Threads belonging to the same interpreter
     share their module administration and a few other internal items.
     There are no public members in this structure.

     Threads belonging to different interpreters initially share
     nothing, except process state like available memory, open file
     descriptors and such.  The global interpreter lock is also shared
     by all threads, regardless of to which interpreter they belong.

     Changed in version 3.12: PEP 684(1) introduced the possibility of a
     *note per-interpreter GIL: 51c3.  See *note
     Py_NewInterpreterFromConfig(): 45f.

 -- C Type: type PyThreadState
     ' Part of the *note Limited API: 556. (as an opaque struct).'  This
     data structure represents the state of a single thread.  The only
     public data member is:

      -- C Member: *note PyInterpreterState: 8c5. *interp

          This thread’s interpreter state.

 -- C Function: void PyEval_InitThreads ()
     ' Part of the *note Stable ABI: 556.'

     Deprecated function which does nothing.

     In Python 3.6 and older, this function created the GIL if it didn’t
     exist.

     Changed in version 3.9: The function now does nothing.

     Changed in version 3.7: This function is now called by *note
     Py_Initialize(): 8b4, so you don’t have to call it yourself
     anymore.

     Changed in version 3.2: This function cannot be called before *note
     Py_Initialize(): 8b4. anymore.

     Deprecated since version 3.9.

 -- C Function: *note PyThreadState: 790. *PyEval_SaveThread ()
     ' Part of the *note Stable ABI: 556.'  Release the global
     interpreter lock (if it has been created) and reset the thread
     state to ‘NULL’, returning the previous thread state (which is not
     ‘NULL’).  If the lock has been created, the current thread must
     have acquired it.

 -- C Function: void PyEval_RestoreThread (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Acquire the global
     interpreter lock (if it has been created) and set the thread state
     to 'tstate', which must not be ‘NULL’.  If the lock has been
     created, the current thread must not have acquired it, otherwise
     deadlock ensues.

          Note: Calling this function from a thread when the runtime is
          finalizing will hang the thread until the program exits, even
          if the thread was not created by Python.  Refer to *note
          Cautions regarding runtime finalization: 51c0. for more
          details.

     Changed in version 3.13.8: Hangs the current thread, rather than
     terminating it, if called while the interpreter is finalizing.

 -- C Function: *note PyThreadState: 790. *PyThreadState_Get ()
     ' Part of the *note Stable ABI: 556.'  Return the current thread
     state.  The global interpreter lock must be held.  When the current
     thread state is ‘NULL’, this issues a fatal error (so that the
     caller needn’t check for ‘NULL’).

     See also *note PyThreadState_GetUnchecked(): 374.

 -- C Function: *note PyThreadState: 790. *PyThreadState_GetUnchecked ()

     Similar to *note PyThreadState_Get(): 375, but don’t kill the
     process with a fatal error if it is NULL. The caller is responsible
     to check if the result is NULL.

     Added in version 3.13: In Python 3.5 to 3.12, the function was
     private and known as ‘_PyThreadState_UncheckedGet()’.

 -- C Function: *note PyThreadState: 790. *PyThreadState_Swap
          (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Swap the current thread
     state with the thread state given by the argument 'tstate', which
     may be ‘NULL’.

     The *note GIL: 159. does not need to be held, but will be held upon
     returning if 'tstate' is non-‘NULL’.

The following functions use thread-local storage, and are not compatible
with sub-interpreters:

 -- C Type: type PyGILState_STATE
     ' Part of the *note Stable ABI: 556.'  The type of the value
     returned by *note PyGILState_Ensure(): 3ae. and passed to *note
     PyGILState_Release(): 3af.

      -- C Enumerator: enumerator PyGILState_LOCKED

          The GIL was already held when *note PyGILState_Ensure(): 3ae.
          was called.

      -- C Enumerator: enumerator PyGILState_UNLOCKED

          The GIL was not held when *note PyGILState_Ensure(): 3ae. was
          called.

 -- C Function: *note PyGILState_STATE: 4cf0. PyGILState_Ensure ()
     ' Part of the *note Stable ABI: 556.'  Ensure that the current
     thread is ready to call the Python C API regardless of the current
     state of Python, or of the global interpreter lock.  This may be
     called as many times as desired by a thread as long as each call is
     matched with a call to *note PyGILState_Release(): 3af.  In
     general, other thread-related APIs may be used between *note
     PyGILState_Ensure(): 3ae. and ‘PyGILState_Release()’ calls as long
     as the thread state is restored to its previous state before the
     Release().  For example, normal usage of the *note
     Py_BEGIN_ALLOW_THREADS: 4b88. and *note Py_END_ALLOW_THREADS: a9d.
     macros is acceptable.

     The return value is an opaque “handle” to the thread state when
     *note PyGILState_Ensure(): 3ae. was called, and must be passed to
     *note PyGILState_Release(): 3af. to ensure Python is left in the
     same state.  Even though recursive calls are allowed, these handles
     'cannot' be shared - each unique call to ‘PyGILState_Ensure()’ must
     save the handle for its call to ‘PyGILState_Release()’.

     When the function returns, the current thread will hold the GIL and
     be able to call arbitrary Python code.  Failure is a fatal error.

          Note: Calling this function from a thread when the runtime is
          finalizing will hang the thread until the program exits, even
          if the thread was not created by Python.  Refer to *note
          Cautions regarding runtime finalization: 51c0. for more
          details.

     Changed in version 3.13.8: Hangs the current thread, rather than
     terminating it, if called while the interpreter is finalizing.

 -- C Function: void PyGILState_Release (PyGILState_STATE)
     ' Part of the *note Stable ABI: 556.'  Release any resources
     previously acquired.  After this call, Python’s state will be the
     same as it was prior to the corresponding *note
     PyGILState_Ensure(): 3ae. call (but generally this state will be
     unknown to the caller, hence the use of the GILState API).

     Every call to *note PyGILState_Ensure(): 3ae. must be matched by a
     call to *note PyGILState_Release(): 3af. on the same thread.

 -- C Function: *note PyThreadState: 790. *PyGILState_GetThisThreadState
          ()
     ' Part of the *note Stable ABI: 556.'  Get the current thread state
     for this thread.  May return ‘NULL’ if no GILState API has been
     used on the current thread.  Note that the main thread always has
     such a thread-state, even if no auto-thread-state call has been
     made on the main thread.  This is mainly a helper/diagnostic
     function.

 -- C Function: int PyGILState_Check ()

     Return ‘1’ if the current thread is holding the GIL and ‘0’
     otherwise.  This function can be called from any thread at any
     time.  Only if it has had its Python thread state initialized and
     currently is holding the GIL will it return ‘1’.  This is mainly a
     helper/diagnostic function.  It can be useful for example in
     callback contexts or memory allocation functions when knowing that
     the GIL is locked can allow the caller to perform sensitive actions
     or otherwise behave differently.

     Added in version 3.4.

The following macros are normally used without a trailing semicolon;
look for example usage in the Python source distribution.

 -- C Macro: Py_BEGIN_ALLOW_THREADS
     ' Part of the *note Stable ABI: 556.'  This macro expands to ‘{
     PyThreadState *_save; _save = PyEval_SaveThread();’.  Note that it
     contains an opening brace; it must be matched with a following
     *note Py_END_ALLOW_THREADS: a9d. macro.  See above for further
     discussion of this macro.

 -- C Macro: Py_END_ALLOW_THREADS
     ' Part of the *note Stable ABI: 556.'  This macro expands to
     ‘PyEval_RestoreThread(_save); }’.  Note that it contains a closing
     brace; it must be matched with an earlier *note
     Py_BEGIN_ALLOW_THREADS: 4b88. macro.  See above for further
     discussion of this macro.

 -- C Macro: Py_BLOCK_THREADS
     ' Part of the *note Stable ABI: 556.'  This macro expands to
     ‘PyEval_RestoreThread(_save);’: it is equivalent to *note
     Py_END_ALLOW_THREADS: a9d. without the closing brace.

 -- C Macro: Py_UNBLOCK_THREADS
     ' Part of the *note Stable ABI: 556.'  This macro expands to ‘_save
     = PyEval_SaveThread();’: it is equivalent to *note
     Py_BEGIN_ALLOW_THREADS: 4b88. without the opening brace and
     variable declaration.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0684/


File: python.info,  Node: Low-level API,  Prev: High-level API,  Up: Thread State and the Global Interpreter Lock

7.9.5.6 Low-level API
.....................

All of the following functions must be called after *note
Py_Initialize(): 8b4.

Changed in version 3.7: *note Py_Initialize(): 8b4. now initializes the
*note GIL: 159.

 -- C Function: *note PyInterpreterState: 8c5. *PyInterpreterState_New
          ()
     ' Part of the *note Stable ABI: 556.'  Create a new interpreter
     state object.  The global interpreter lock need not be held, but
     may be held if it is necessary to serialize calls to this function.

     Raises an *note auditing event: 1a15.
     ‘cpython.PyInterpreterState_New’ with no arguments.

 -- C Function: void PyInterpreterState_Clear (PyInterpreterState
          *interp)
     ' Part of the *note Stable ABI: 556.'  Reset all information in an
     interpreter state object.  The global interpreter lock must be
     held.

     Raises an *note auditing event: 1a15.
     ‘cpython.PyInterpreterState_Clear’ with no arguments.

 -- C Function: void PyInterpreterState_Delete (PyInterpreterState
          *interp)
     ' Part of the *note Stable ABI: 556.'  Destroy an interpreter state
     object.  The global interpreter lock need not be held.  The
     interpreter state must have been reset with a previous call to
     *note PyInterpreterState_Clear(): 4421.

 -- C Function: *note PyThreadState: 790. *PyThreadState_New
          (PyInterpreterState *interp)
     ' Part of the *note Stable ABI: 556.'  Create a new thread state
     object belonging to the given interpreter object.  The global
     interpreter lock need not be held, but may be held if it is
     necessary to serialize calls to this function.

 -- C Function: void PyThreadState_Clear (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Reset all information in a
     thread state object.  The global interpreter lock must be held.

     Changed in version 3.9: This function now calls the
     ‘PyThreadState.on_delete’ callback.  Previously, that happened in
     *note PyThreadState_Delete(): 1b32.

     Changed in version 3.13: The ‘PyThreadState.on_delete’ callback was
     removed.

 -- C Function: void PyThreadState_Delete (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Destroy a thread state
     object.  The global interpreter lock need not be held.  The thread
     state must have been reset with a previous call to *note
     PyThreadState_Clear(): 1729.

 -- C Function: void PyThreadState_DeleteCurrent (void)

     Destroy the current thread state and release the global interpreter
     lock.  Like *note PyThreadState_Delete(): 1b32, the global
     interpreter lock must be held.  The thread state must have been
     reset with a previous call to *note PyThreadState_Clear(): 1729.

 -- C Function: *note PyFrameObject: 78c. *PyThreadState_GetFrame
          (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Get the
     current frame of the Python thread state 'tstate'.

     Return a *note strong reference: 33e.  Return ‘NULL’ if no frame is
     currently executing.

     See also *note PyEval_GetFrame(): 18dc.

     'tstate' must not be ‘NULL’.

     Added in version 3.9.

 -- C Function: uint64_t PyThreadState_GetID (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Get the
     unique thread state identifier of the Python thread state 'tstate'.

     'tstate' must not be ‘NULL’.

     Added in version 3.9.

 -- C Function: *note PyInterpreterState: 8c5.
          *PyThreadState_GetInterpreter (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Get the
     interpreter of the Python thread state 'tstate'.

     'tstate' must not be ‘NULL’.

     Added in version 3.9.

 -- C Function: void PyThreadState_EnterTracing (PyThreadState *tstate)

     Suspend tracing and profiling in the Python thread state 'tstate'.

     Resume them using the *note PyThreadState_LeaveTracing(): 758.
     function.

     Added in version 3.11.

 -- C Function: void PyThreadState_LeaveTracing (PyThreadState *tstate)

     Resume tracing and profiling in the Python thread state 'tstate'
     suspended by the *note PyThreadState_EnterTracing(): 757. function.

     See also *note PyEval_SetTrace(): 424. and *note
     PyEval_SetProfile(): 154c. functions.

     Added in version 3.11.

 -- C Function: *note PyInterpreterState: 8c5. *PyInterpreterState_Get
          (void)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Get the
     current interpreter.

     Issue a fatal error if there is no current Python thread state or
     no current interpreter.  It cannot return NULL.

     The caller must hold the GIL.

     Added in version 3.9.

 -- C Function: int64_t PyInterpreterState_GetID (PyInterpreterState
          *interp)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return
     the interpreter’s unique ID. If there was any error in doing so
     then ‘-1’ is returned and an error is set.

     The caller must hold the GIL.

     Added in version 3.7.

 -- C Function: *note PyObject: 33a. *PyInterpreterState_GetDict
          (PyInterpreterState *interp)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556. since version 3.8.'  Return a dictionary in which
     interpreter-specific data may be stored.  If this function returns
     ‘NULL’ then no exception has been raised and the caller should
     assume no interpreter-specific dict is available.

     This is not a replacement for *note PyModule_GetState(): 98a, which
     extensions should use to store interpreter-specific state
     information.

     The returned dictionary is borrowed from the interpreter and is
     valid until interpreter shutdown.

     Added in version 3.8.

 -- C Function: *note PyObject: 33a.
          *PyUnstable_InterpreterState_GetMainModule (PyInterpreterState
          *interp)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Return a *note strong reference: 33e. to the ‘__main__’ *note
     module object: 50db. for the given interpreter.

     The caller must hold the GIL.

     Added in version 3.13.

 -- C Type: typedef *note PyObject: 33a. *(*_PyFrameEvalFunction)(*note
          PyThreadState: 790. *tstate, *note _PyInterpreterFrame: 5137.
          *frame, int throwflag)

     Type of a frame evaluation function.

     The 'throwflag' parameter is used by the ‘throw()’ method of
     generators: if non-zero, handle the current exception.

     Changed in version 3.9: The function now takes a 'tstate'
     parameter.

     Changed in version 3.11: The 'frame' parameter changed from
     ‘PyFrameObject*’ to ‘_PyInterpreterFrame*’.

 -- C Function: *note _PyFrameEvalFunction: 779.
          _PyInterpreterState_GetEvalFrameFunc (PyInterpreterState
          *interp)

     Get the frame evaluation function.

     See the PEP 523(1) “Adding a frame evaluation API to CPython”.

     Added in version 3.9.

 -- C Function: void _PyInterpreterState_SetEvalFrameFunc
          (PyInterpreterState *interp, _PyFrameEvalFunction eval_frame)

     Set the frame evaluation function.

     See the PEP 523(2) “Adding a frame evaluation API to CPython”.

     Added in version 3.9.

 -- C Function: *note PyObject: 33a. *PyThreadState_GetDict ()
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Return a dictionary in which extensions can store
     thread-specific state information.  Each extension should use a
     unique key to use to store state in the dictionary.  It is okay to
     call this function when no current thread state is available.  If
     this function returns ‘NULL’, no exception has been raised and the
     caller should assume no current thread state is available.

 -- C Function: int PyThreadState_SetAsyncExc (unsigned long id,
          PyObject *exc)
     ' Part of the *note Stable ABI: 556.'  Asynchronously raise an
     exception in a thread.  The 'id' argument is the thread id of the
     target thread; 'exc' is the exception object to be raised.  This
     function does not steal any references to 'exc'.  To prevent naive
     misuse, you must write your own C extension to call this.  Must be
     called with the GIL held.  Returns the number of thread states
     modified; this is normally one, but will be zero if the thread id
     isn’t found.  If 'exc' is ‘NULL’, the pending exception (if any)
     for the thread is cleared.  This raises no exceptions.

     Changed in version 3.7: The type of the 'id' parameter changed from
     long to unsigned long.

 -- C Function: void PyEval_AcquireThread (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Acquire the global
     interpreter lock and set the current thread state to 'tstate',
     which must not be ‘NULL’.  The lock must have been created earlier.
     If this thread already has the lock, deadlock ensues.

          Note: Calling this function from a thread when the runtime is
          finalizing will hang the thread until the program exits, even
          if the thread was not created by Python.  Refer to *note
          Cautions regarding runtime finalization: 51c0. for more
          details.

     Changed in version 3.8: Updated to be consistent with *note
     PyEval_RestoreThread(): 3ac, *note Py_END_ALLOW_THREADS(): a9d, and
     *note PyGILState_Ensure(): 3ae, and terminate the current thread if
     called while the interpreter is finalizing.

     Changed in version 3.13.8: Hangs the current thread, rather than
     terminating it, if called while the interpreter is finalizing.

     *note PyEval_RestoreThread(): 3ac. is a higher-level function which
     is always available (even when threads have not been initialized).

 -- C Function: void PyEval_ReleaseThread (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'  Reset the current thread
     state to ‘NULL’ and release the global interpreter lock.  The lock
     must have been created earlier and must be held by the current
     thread.  The 'tstate' argument, which must not be ‘NULL’, is only
     used to check that it represents the current thread state — if it
     isn’t, a fatal error is reported.

     *note PyEval_SaveThread(): 3ab. is a higher-level function which is
     always available (even when threads have not been initialized).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0523/

   (2) https://peps.python.org/pep-0523/


File: python.info,  Node: Sub-interpreter support,  Next: Asynchronous Notifications,  Prev: Thread State and the Global Interpreter Lock,  Up: Initialization Finalization and Threads

7.9.6 Sub-interpreter support
-----------------------------

While in most uses, you will only embed a single Python interpreter,
there are cases where you need to create several independent
interpreters in the same process and perhaps even in the same thread.
Sub-interpreters allow you to do that.

The “main” interpreter is the first one created when the runtime
initializes.  It is usually the only Python interpreter in a process.
Unlike sub-interpreters, the main interpreter has unique process-global
responsibilities like signal handling.  It is also responsible for
execution during runtime initialization and is usually the active
interpreter during runtime finalization.  The *note
PyInterpreterState_Main(): 51cb. function returns a pointer to its
state.

You can switch between sub-interpreters using the *note
PyThreadState_Swap(): 4d8c. function.  You can create and destroy them
using the following functions:

 -- C Type: type PyInterpreterConfig

     Structure containing most parameters to configure a
     sub-interpreter.  Its values are used only in *note
     Py_NewInterpreterFromConfig(): 45f. and never modified by the
     runtime.

     Added in version 3.12.

     Structure fields:

      -- C Member: int use_main_obmalloc

          If this is ‘0’ then the sub-interpreter will use its own
          “object” allocator state.  Otherwise it will use (share) the
          main interpreter’s.

          If this is ‘0’ then *note check_multi_interp_extensions: 51cc.
          must be ‘1’ (non-zero).  If this is ‘1’ then *note gil: 51cd.
          must not be *note PyInterpreterConfig_OWN_GIL: 51ce.

      -- C Member: int allow_fork

          If this is ‘0’ then the runtime will not support forking the
          process in any thread where the sub-interpreter is currently
          active.  Otherwise fork is unrestricted.

          Note that the *note subprocess: d6. module still works when
          fork is disallowed.

      -- C Member: int allow_exec

          If this is ‘0’ then the runtime will not support replacing the
          current process via exec (e.g.  *note os.execv(): 2d16.) in
          any thread where the sub-interpreter is currently active.
          Otherwise exec is unrestricted.

          Note that the *note subprocess: d6. module still works when
          exec is disallowed.

      -- C Member: int allow_threads

          If this is ‘0’ then the sub-interpreter’s *note threading: ed.
          module won’t create threads.  Otherwise threads are allowed.

      -- C Member: int allow_daemon_threads

          If this is ‘0’ then the sub-interpreter’s *note threading: ed.
          module won’t create daemon threads.  Otherwise daemon threads
          are allowed (as long as *note allow_threads: 51d1. is
          non-zero).

      -- C Member: int check_multi_interp_extensions

          If this is ‘0’ then all extension modules may be imported,
          including legacy (single-phase init) modules, in any thread
          where the sub-interpreter is currently active.  Otherwise only
          multi-phase init extension modules (see PEP 489(1)) may be
          imported.  (Also see *note Py_mod_multiple_interpreters:
          4e11.)

          This must be ‘1’ (non-zero) if *note use_main_obmalloc: 45de.
          is ‘0’.

      -- C Member: int gil

          This determines the operation of the GIL for the
          sub-interpreter.  It may be one of the following:

           -- C Macro: PyInterpreterConfig_DEFAULT_GIL

               Use the default selection (*note
               PyInterpreterConfig_SHARED_GIL: 51d4.).

           -- C Macro: PyInterpreterConfig_SHARED_GIL

               Use (share) the main interpreter’s GIL.

           -- C Macro: PyInterpreterConfig_OWN_GIL

               Use the sub-interpreter’s own GIL.

          If this is *note PyInterpreterConfig_OWN_GIL: 51ce. then *note
          PyInterpreterConfig.use_main_obmalloc: 45de. must be ‘0’.

 -- C Function: *note PyStatus: 9b8. Py_NewInterpreterFromConfig
          (PyThreadState **tstate_p, const PyInterpreterConfig *config)

     Create a new sub-interpreter.  This is an (almost) totally separate
     environment for the execution of Python code.  In particular, the
     new interpreter has separate, independent versions of all imported
     modules, including the fundamental modules *note builtins: 12,
     *note __main__: 1. and *note sys: d9.  The table of loaded modules
     (‘sys.modules’) and the module search path (‘sys.path’) are also
     separate.  The new environment has no ‘sys.argv’ variable.  It has
     new standard I/O stream file objects ‘sys.stdin’, ‘sys.stdout’ and
     ‘sys.stderr’ (however these refer to the same underlying file
     descriptors).

     The given 'config' controls the options with which the interpreter
     is initialized.

     Upon success, 'tstate_p' will be set to the first thread state
     created in the new sub-interpreter.  This thread state is made in
     the current thread state.  Note that no actual thread is created;
     see the discussion of thread states below.  If creation of the new
     interpreter is unsuccessful, 'tstate_p' is set to ‘NULL’; no
     exception is set since the exception state is stored in the current
     thread state and there may not be a current thread state.

     Like all other Python/C API functions, the global interpreter lock
     must be held before calling this function and is still held when it
     returns.  Likewise a current thread state must be set on entry.  On
     success, the returned thread state will be set as current.  If the
     sub-interpreter is created with its own GIL then the GIL of the
     calling interpreter will be released.  When the function returns,
     the new interpreter’s GIL will be held by the current thread and
     the previously interpreter’s GIL will remain released here.

     Added in version 3.12.

     Sub-interpreters are most effective when isolated from each other,
     with certain functionality restricted:

          PyInterpreterConfig config = {
              .use_main_obmalloc = 0,
              .allow_fork = 0,
              .allow_exec = 0,
              .allow_threads = 1,
              .allow_daemon_threads = 0,
              .check_multi_interp_extensions = 1,
              .gil = PyInterpreterConfig_OWN_GIL,
          };
          PyThreadState *tstate = NULL;
          PyStatus status = Py_NewInterpreterFromConfig(&tstate, &config);
          if (PyStatus_Exception(status)) {
              Py_ExitStatusException(status);
          }

     Note that the config is used only briefly and does not get
     modified.  During initialization the config’s values are converted
     into various *note PyInterpreterState: 8c5. values.  A read-only
     copy of the config may be stored internally on the
     ‘PyInterpreterState’.

     Extension modules are shared between (sub-)interpreters as follows:

        * For modules using multi-phase initialization, e.g.  *note
          PyModule_FromDefAndSpec(): ee7, a separate module object is
          created and initialized for each interpreter.  Only C-level
          static and global variables are shared between these module
          objects.

        * For modules using single-phase initialization, e.g.  *note
          PyModule_Create(): 50e0, the first time a particular extension
          is imported, it is initialized normally, and a (shallow) copy
          of its module’s dictionary is squirreled away.  When the same
          extension is imported by another (sub-)interpreter, a new
          module is initialized and filled with the contents of this
          copy; the extension’s ‘init’ function is not called.  Objects
          in the module’s dictionary thus end up shared across
          (sub-)interpreters, which might cause unwanted behavior (see
          *note Bugs and caveats: 51d5. below).

          Note that this is different from what happens when an
          extension is imported after the interpreter has been
          completely re-initialized by calling *note Py_FinalizeEx():
          d3d. and *note Py_Initialize(): 8b4.; in that case, the
          extension’s ‘initmodule’ function 'is' called again.  As with
          multi-phase initialization, this means that only C-level
          static and global variables are shared between these modules.

 -- C Function: *note PyThreadState: 790. *Py_NewInterpreter (void)
     ' Part of the *note Stable ABI: 556.'

     Create a new sub-interpreter.  This is essentially just a wrapper
     around *note Py_NewInterpreterFromConfig(): 45f. with a config that
     preserves the existing behavior.  The result is an unisolated
     sub-interpreter that shares the main interpreter’s GIL, allows
     fork/exec, allows daemon threads, and allows single-phase init
     modules.

 -- C Function: void Py_EndInterpreter (PyThreadState *tstate)
     ' Part of the *note Stable ABI: 556.'

     Destroy the (sub-)interpreter represented by the given thread
     state.  The given thread state must be the current thread state.
     See the discussion of thread states below.  When the call returns,
     the current thread state is ‘NULL’.  All thread states associated
     with this interpreter are destroyed.  The global interpreter lock
     used by the target interpreter must be held before calling this
     function.  No GIL is held when it returns.

     *note Py_FinalizeEx(): d3d. will destroy all sub-interpreters that
     haven’t been explicitly destroyed at that point.

* Menu:

* A Per-Interpreter GIL::
* Bugs and caveats::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0489/


File: python.info,  Node: A Per-Interpreter GIL,  Next: Bugs and caveats,  Up: Sub-interpreter support

7.9.6.1 A Per-Interpreter GIL
.............................

Using *note Py_NewInterpreterFromConfig(): 45f. you can create a
sub-interpreter that is completely isolated from other interpreters,
including having its own GIL. The most important benefit of this
isolation is that such an interpreter can execute Python code without
being blocked by other interpreters or blocking any others.  Thus a
single Python process can truly take advantage of multiple CPU cores
when running Python code.  The isolation also encourages a different
approach to concurrency than that of just using threads.  (See PEP
554(1) and PEP 684(2).)

Using an isolated interpreter requires vigilance in preserving that
isolation.  That especially means not sharing any objects or mutable
state without guarantees about thread-safety.  Even objects that are
otherwise immutable (e.g.  ‘None’, ‘(1, 5)’) can’t normally be shared
because of the refcount.  One simple but less-efficient approach around
this is to use a global lock around all use of some state (or object).
Alternately, effectively immutable objects (like integers or strings)
can be made safe in spite of their refcounts by making them *note
immortal: 45dd.  In fact, this has been done for the builtin singletons,
small integers, and a number of other builtin objects.

If you preserve isolation then you will have access to proper multi-core
computing without the complications that come with free-threading.
Failure to preserve isolation will expose you to the full consequences
of free-threading, including races and hard-to-debug crashes.

Aside from that, one of the main challenges of using multiple isolated
interpreters is how to communicate between them safely (not break
isolation) and efficiently.  The runtime and stdlib do not provide any
standard approach to this yet.  A future stdlib module would help
mitigate the effort of preserving isolation and expose effective tools
for communicating (and sharing) data between interpreters.

Added in version 3.12.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0554/

   (2) https://peps.python.org/pep-0684/


File: python.info,  Node: Bugs and caveats,  Prev: A Per-Interpreter GIL,  Up: Sub-interpreter support

7.9.6.2 Bugs and caveats
........................

Because sub-interpreters (and the main interpreter) are part of the same
process, the insulation between them isn’t perfect — for example, using
low-level file operations like *note os.close(): b90. they can
(accidentally or maliciously) affect each other’s open files.  Because
of the way extensions are shared between (sub-)interpreters, some
extensions may not work properly; this is especially likely when using
single-phase initialization or (static) global variables.  It is
possible to insert objects created in one sub-interpreter into a
namespace of another (sub-)interpreter; this should be avoided if
possible.

Special care should be taken to avoid sharing user-defined functions,
methods, instances or classes between sub-interpreters, since import
operations executed by such objects may affect the wrong
(sub-)interpreter’s dictionary of loaded modules.  It is equally
important to avoid sharing objects from which the above are reachable.

Also note that combining this functionality with ‘PyGILState_*’ APIs is
delicate, because these APIs assume a bijection between Python thread
states and OS-level threads, an assumption broken by the presence of
sub-interpreters.  It is highly recommended that you don’t switch
sub-interpreters between a pair of matching *note PyGILState_Ensure():
3ae. and *note PyGILState_Release(): 3af. calls.  Furthermore,
extensions (such as *note ctypes: 2a.) using these APIs to allow calling
of Python code from non-Python created threads will probably be broken
when using sub-interpreters.


File: python.info,  Node: Asynchronous Notifications,  Next: Profiling and Tracing,  Prev: Sub-interpreter support,  Up: Initialization Finalization and Threads

7.9.7 Asynchronous Notifications
--------------------------------

A mechanism is provided to make asynchronous notifications to the main
interpreter thread.  These notifications take the form of a function
pointer and a void pointer argument.

 -- C Function: int Py_AddPendingCall (int (*func)(void*), void *arg)
     ' Part of the *note Stable ABI: 556.'  Schedule a function to be
     called from the main interpreter thread.  On success, ‘0’ is
     returned and 'func' is queued for being called in the main thread.
     On failure, ‘-1’ is returned without setting any exception.

     When successfully queued, 'func' will be 'eventually' called from
     the main interpreter thread with the argument 'arg'.  It will be
     called asynchronously with respect to normally running Python code,
     but with both these conditions met:

        * on a *note bytecode: 187. boundary;

        * with the main thread holding the *note global interpreter
          lock: 148. ('func' can therefore use the full C API).

     'func' must return ‘0’ on success, or ‘-1’ on failure with an
     exception set.  'func' won’t be interrupted to perform another
     asynchronous notification recursively, but it can still be
     interrupted to switch threads if the global interpreter lock is
     released.

     This function doesn’t need a current thread state to run, and it
     doesn’t need the global interpreter lock.

     To call this function in a subinterpreter, the caller must hold the
     GIL. Otherwise, the function 'func' can be scheduled to be called
     from the wrong interpreter.

          Warning: This is a low-level function, only useful for very
          special cases.  There is no guarantee that 'func' will be
          called as quick as possible.  If the main thread is busy
          executing a system call, 'func' won’t be called before the
          system call returns.  This function is generally 'not'
          suitable for calling Python code from arbitrary C threads.
          Instead, use the *note PyGILState API: 51bd.

     Added in version 3.1.

     Changed in version 3.9: If this function is called in a
     subinterpreter, the function 'func' is now scheduled to be called
     from the subinterpreter, rather than being called from the main
     interpreter.  Each subinterpreter now has its own list of scheduled
     calls.

     Changed in version 3.12: This function now always schedules 'func'
     to be run in the main interpreter.

 -- C Function: int Py_MakePendingCalls (void)
     ' Part of the *note Stable ABI: 556.'  Execute all pending calls.
     This is usually executed automatically by the interpreter.

     This function returns ‘0’ on success, and returns ‘-1’ with an
     exception set on failure.

     If this is not called in the main thread of the main interpreter,
     this function does nothing and returns ‘0’.  The caller must hold
     the *note GIL: 159.

     Added in version 3.1.

     Changed in version 3.12: This function only runs pending calls in
     the main interpreter.


File: python.info,  Node: Profiling and Tracing,  Next: Reference tracing,  Prev: Asynchronous Notifications,  Up: Initialization Finalization and Threads

7.9.8 Profiling and Tracing
---------------------------

The Python interpreter provides some low-level support for attaching
profiling and execution tracing facilities.  These are used for
profiling, debugging, and coverage analysis tools.

This C interface allows the profiling or tracing code to avoid the
overhead of calling through Python-level callable objects, making a
direct C function call instead.  The essential attributes of the
facility have not changed; the interface allows trace functions to be
installed per-thread, and the basic events reported to the trace
function are the same as had been reported to the Python-level trace
functions in previous versions.

 -- C Type: typedef int (*Py_tracefunc)(*note PyObject: 33a. *obj, *note
          PyFrameObject: 78c. *frame, int what, *note PyObject: 33a.
          *arg)

     The type of the trace function registered using *note
     PyEval_SetProfile(): 154c. and *note PyEval_SetTrace(): 424.  The
     first parameter is the object passed to the registration function
     as 'obj', 'frame' is the frame object to which the event pertains,
     'what' is one of the constants *note PyTrace_CALL: 51db, *note
     PyTrace_EXCEPTION: 51dc, *note PyTrace_LINE: 51dd, *note
     PyTrace_RETURN: 51de, *note PyTrace_C_CALL: 51df, *note
     PyTrace_C_EXCEPTION: 51e0, *note PyTrace_C_RETURN: 51e1, or *note
     PyTrace_OPCODE: 51e2, and 'arg' depends on the value of 'what':

     Value of 'what'                     Meaning of 'arg'
                                         
     ---------------------------------------------------------------------------------
                                         
     *note PyTrace_CALL: 51db.           Always *note Py_None: 4b69.
                                         
                                         
     *note PyTrace_EXCEPTION: 51dc.      Exception information as returned by
                                         *note sys.exc_info(): 68d.
                                         
                                         
     *note PyTrace_LINE: 51dd.           Always *note Py_None: 4b69.
                                         
                                         
     *note PyTrace_RETURN: 51de.         Value being returned to the caller, or
                                         ‘NULL’ if caused by an exception.
                                         
                                         
     *note PyTrace_C_CALL: 51df.         Function object being called.
                                         
                                         
     *note PyTrace_C_EXCEPTION: 51e0.    Function object being called.
                                         
                                         
     *note PyTrace_C_RETURN: 51e1.       Function object being called.
                                         
                                         
     *note PyTrace_OPCODE: 51e2.         Always *note Py_None: 4b69.
                                         

 -- C Variable: int PyTrace_CALL

     The value of the 'what' parameter to a *note Py_tracefunc: 51da.
     function when a new call to a function or method is being reported,
     or a new entry into a generator.  Note that the creation of the
     iterator for a generator function is not reported as there is no
     control transfer to the Python bytecode in the corresponding frame.

 -- C Variable: int PyTrace_EXCEPTION

     The value of the 'what' parameter to a *note Py_tracefunc: 51da.
     function when an exception has been raised.  The callback function
     is called with this value for 'what' when after any bytecode is
     processed after which the exception becomes set within the frame
     being executed.  The effect of this is that as exception
     propagation causes the Python stack to unwind, the callback is
     called upon return to each frame as the exception propagates.  Only
     trace functions receive these events; they are not needed by the
     profiler.

 -- C Variable: int PyTrace_LINE

     The value passed as the 'what' parameter to a *note Py_tracefunc:
     51da. function (but not a profiling function) when a line-number
     event is being reported.  It may be disabled for a frame by setting
     *note f_trace_lines: bfc. to '0' on that frame.

 -- C Variable: int PyTrace_RETURN

     The value for the 'what' parameter to *note Py_tracefunc: 51da.
     functions when a call is about to return.

 -- C Variable: int PyTrace_C_CALL

     The value for the 'what' parameter to *note Py_tracefunc: 51da.
     functions when a C function is about to be called.

 -- C Variable: int PyTrace_C_EXCEPTION

     The value for the 'what' parameter to *note Py_tracefunc: 51da.
     functions when a C function has raised an exception.

 -- C Variable: int PyTrace_C_RETURN

     The value for the 'what' parameter to *note Py_tracefunc: 51da.
     functions when a C function has returned.

 -- C Variable: int PyTrace_OPCODE

     The value for the 'what' parameter to *note Py_tracefunc: 51da.
     functions (but not profiling functions) when a new opcode is about
     to be executed.  This event is not emitted by default: it must be
     explicitly requested by setting *note f_trace_opcodes: bfd. to '1'
     on the frame.

 -- C Function: void PyEval_SetProfile (Py_tracefunc func, PyObject
          *obj)

     Set the profiler function to 'func'.  The 'obj' parameter is passed
     to the function as its first parameter, and may be any Python
     object, or ‘NULL’.  If the profile function needs to maintain
     state, using a different value for 'obj' for each thread provides a
     convenient and thread-safe place to store it.  The profile function
     is called for all monitored events except *note PyTrace_LINE: 51dd.
     *note PyTrace_OPCODE: 51e2. and *note PyTrace_EXCEPTION: 51dc.

     See also the *note sys.setprofile(): 154d. function.

     The caller must hold the *note GIL: 159.

 -- C Function: void PyEval_SetProfileAllThreads (Py_tracefunc func,
          PyObject *obj)

     Like *note PyEval_SetProfile(): 154c. but sets the profile function
     in all running threads belonging to the current interpreter instead
     of the setting it only on the current thread.

     The caller must hold the *note GIL: 159.

     As *note PyEval_SetProfile(): 154c, this function ignores any
     exceptions raised while setting the profile functions in all
     threads.

Added in version 3.12.

 -- C Function: void PyEval_SetTrace (Py_tracefunc func, PyObject *obj)

     Set the tracing function to 'func'.  This is similar to *note
     PyEval_SetProfile(): 154c, except the tracing function does receive
     line-number events and per-opcode events, but does not receive any
     event related to C function objects being called.  Any trace
     function registered using *note PyEval_SetTrace(): 424. will not
     receive *note PyTrace_C_CALL: 51df, *note PyTrace_C_EXCEPTION:
     51e0. or *note PyTrace_C_RETURN: 51e1. as a value for the 'what'
     parameter.

     See also the *note sys.settrace(): 154e. function.

     The caller must hold the *note GIL: 159.

 -- C Function: void PyEval_SetTraceAllThreads (Py_tracefunc func,
          PyObject *obj)

     Like *note PyEval_SetTrace(): 424. but sets the tracing function in
     all running threads belonging to the current interpreter instead of
     the setting it only on the current thread.

     The caller must hold the *note GIL: 159.

     As *note PyEval_SetTrace(): 424, this function ignores any
     exceptions raised while setting the trace functions in all threads.

Added in version 3.12.


File: python.info,  Node: Reference tracing,  Next: Advanced Debugger Support,  Prev: Profiling and Tracing,  Up: Initialization Finalization and Threads

7.9.9 Reference tracing
-----------------------

Added in version 3.13.

 -- C Type: typedef int (*PyRefTracer)(*note PyObject: 33a.*, int event,
          void *data)

     The type of the trace function registered using *note
     PyRefTracer_SetTracer(): 36f.  The first parameter is a Python
     object that has been just created (when 'event' is set to *note
     PyRefTracer_CREATE: 51e5.) or about to be destroyed (when 'event'
     is set to *note PyRefTracer_DESTROY: 51e6.).  The 'data' argument
     is the opaque pointer that was provided when
     ‘PyRefTracer_SetTracer()’ was called.

Added in version 3.13.

 -- C Variable: int PyRefTracer_CREATE

     The value for the 'event' parameter to *note PyRefTracer: 51e4.
     functions when a Python object has been created.

 -- C Variable: int PyRefTracer_DESTROY

     The value for the 'event' parameter to *note PyRefTracer: 51e4.
     functions when a Python object has been destroyed.

 -- C Function: int PyRefTracer_SetTracer (PyRefTracer tracer, void
          *data)

     Register a reference tracer function.  The function will be called
     when a new Python has been created or when an object is going to be
     destroyed.  If 'data' is provided it must be an opaque pointer that
     will be provided when the tracer function is called.  Return ‘0’ on
     success.  Set an exception and return ‘-1’ on error.

     Note that tracer functions 'must not' create Python objects inside
     or otherwise the call will be re-entrant.  The tracer also 'must
     not' clear any existing exception or set an exception.  The GIL
     will be held every time the tracer function is called.

     The GIL must be held when calling this function.

Added in version 3.13.

 -- C Function: *note PyRefTracer: 51e4. PyRefTracer_GetTracer (void
          **data)

     Get the registered reference tracer function and the value of the
     opaque data pointer that was registered when *note
     PyRefTracer_SetTracer(): 36f. was called.  If no tracer was
     registered this function will return NULL and will set the 'data'
     pointer to NULL.

     The GIL must be held when calling this function.

Added in version 3.13.


File: python.info,  Node: Advanced Debugger Support,  Next: Thread Local Storage Support,  Prev: Reference tracing,  Up: Initialization Finalization and Threads

7.9.10 Advanced Debugger Support
--------------------------------

These functions are only intended to be used by advanced debugging
tools.

 -- C Function: *note PyInterpreterState: 8c5. *PyInterpreterState_Head
          ()

     Return the interpreter state object at the head of the list of all
     such objects.

 -- C Function: *note PyInterpreterState: 8c5. *PyInterpreterState_Main
          ()

     Return the main interpreter state object.

 -- C Function: *note PyInterpreterState: 8c5. *PyInterpreterState_Next
          (PyInterpreterState *interp)

     Return the next interpreter state object after 'interp' from the
     list of all such objects.

 -- C Function: *note PyThreadState: 790. *PyInterpreterState_ThreadHead
          (PyInterpreterState *interp)

     Return the pointer to the first *note PyThreadState: 790. object in
     the list of threads associated with the interpreter 'interp'.

 -- C Function: *note PyThreadState: 790. *PyThreadState_Next
          (PyThreadState *tstate)

     Return the next thread state object after 'tstate' from the list of
     all such objects belonging to the same *note PyInterpreterState:
     8c5. object.


File: python.info,  Node: Thread Local Storage Support,  Next: Synchronization Primitives<2>,  Prev: Advanced Debugger Support,  Up: Initialization Finalization and Threads

7.9.11 Thread Local Storage Support
-----------------------------------

The Python interpreter provides low-level support for thread-local
storage (TLS) which wraps the underlying native TLS implementation to
support the Python-level thread local storage API (*note
threading.local: 1650.).  The CPython C level APIs are similar to those
offered by pthreads and Windows: use a thread key and functions to
associate a void* value per thread.

The GIL does 'not' need to be held when calling these functions; they
supply their own locking.

Note that ‘Python.h’ does not include the declaration of the TLS APIs,
you need to include ‘pythread.h’ to use thread-local storage.

     Note: None of these API functions handle memory management on
     behalf of the void* values.  You need to allocate and deallocate
     them yourself.  If the void* values happen to be *note PyObject:
     33a.*, these functions don’t do refcount operations on them either.

* Menu:

* Thread Specific Storage (TSS) API: Thread Specific Storage TSS API.
* Thread Local Storage (TLS) API: Thread Local Storage TLS API.


File: python.info,  Node: Thread Specific Storage TSS API,  Next: Thread Local Storage TLS API,  Up: Thread Local Storage Support

7.9.11.1 Thread Specific Storage (TSS) API
..........................................

TSS API is introduced to supersede the use of the existing TLS API
within the CPython interpreter.  This API uses a new type *note
Py_tss_t: af5. instead of int to represent thread keys.

Added in version 3.7.

See also
........

“A New C-API for Thread-Local Storage in CPython” ( PEP 539(1))

 -- C Type: type Py_tss_t

     This data structure represents the state of a thread key, the
     definition of which may depend on the underlying TLS
     implementation, and it has an internal field representing the key’s
     initialization state.  There are no public members in this
     structure.

     When *note Py_LIMITED_API: 556. is not defined, static allocation
     of this type by *note Py_tss_NEEDS_INIT: 51ec. is allowed.

 -- C Macro: Py_tss_NEEDS_INIT

     This macro expands to the initializer for *note Py_tss_t: af5.
     variables.  Note that this macro won’t be defined with *note
     Py_LIMITED_API: 556.

* Menu:

* Dynamic Allocation::
* Methods: Methods<2>.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0539/


File: python.info,  Node: Dynamic Allocation,  Next: Methods<2>,  Up: Thread Specific Storage TSS API

7.9.11.2 Dynamic Allocation
...........................

Dynamic allocation of the *note Py_tss_t: af5, required in extension
modules built with *note Py_LIMITED_API: 556, where static allocation of
this type is not possible due to its implementation being opaque at
build time.

 -- C Function: *note Py_tss_t: af5. *PyThread_tss_alloc ()
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return a
     value which is the same state as a value initialized with *note
     Py_tss_NEEDS_INIT: 51ec, or ‘NULL’ in the case of dynamic
     allocation failure.

 -- C Function: void PyThread_tss_free (Py_tss_t *key)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Free the
     given 'key' allocated by *note PyThread_tss_alloc(): 408, after
     first calling *note PyThread_tss_delete(): 410. to ensure any
     associated thread locals have been unassigned.  This is a no-op if
     the 'key' argument is ‘NULL’.

          Note: A freed key becomes a dangling pointer.  You should
          reset the key to ‘NULL’.


File: python.info,  Node: Methods<2>,  Prev: Dynamic Allocation,  Up: Thread Specific Storage TSS API

7.9.11.3 Methods
................

The parameter 'key' of these functions must not be ‘NULL’.  Moreover,
the behaviors of *note PyThread_tss_set(): 40c. and *note
PyThread_tss_get(): 40e. are undefined if the given *note Py_tss_t: af5.
has not been initialized by *note PyThread_tss_create(): 4d98.

 -- C Function: int PyThread_tss_is_created (Py_tss_t *key)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return a
     non-zero value if the given *note Py_tss_t: af5. has been
     initialized by *note PyThread_tss_create(): 4d98.

 -- C Function: int PyThread_tss_create (Py_tss_t *key)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return a
     zero value on successful initialization of a TSS key.  The behavior
     is undefined if the value pointed to by the 'key' argument is not
     initialized by *note Py_tss_NEEDS_INIT: 51ec.  This function can be
     called repeatedly on the same key – calling it on an already
     initialized key is a no-op and immediately returns success.

 -- C Function: void PyThread_tss_delete (Py_tss_t *key)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Destroy a
     TSS key to forget the values associated with the key across all
     threads, and change the key’s initialization state to
     uninitialized.  A destroyed key is able to be initialized again by
     *note PyThread_tss_create(): 4d98.  This function can be called
     repeatedly on the same key – calling it on an already destroyed key
     is a no-op.

 -- C Function: int PyThread_tss_set (Py_tss_t *key, void *value)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return a
     zero value to indicate successfully associating a void* value with
     a TSS key in the current thread.  Each thread has a distinct
     mapping of the key to a void* value.

 -- C Function: void *PyThread_tss_get (Py_tss_t *key)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Return
     the void* value associated with a TSS key in the current thread.
     This returns ‘NULL’ if no value is associated with the key in the
     current thread.


File: python.info,  Node: Thread Local Storage TLS API,  Prev: Thread Specific Storage TSS API,  Up: Thread Local Storage Support

7.9.11.4 Thread Local Storage (TLS) API
.......................................

Deprecated since version 3.7: This API is superseded by *note Thread
Specific Storage (TSS) API: af4.

     Note: This version of the API does not support platforms where the
     native TLS key is defined in a way that cannot be safely cast to
     ‘int’.  On such platforms, *note PyThread_create_key(): 407. will
     return immediately with a failure status, and the other TLS
     functions will all be no-ops on such platforms.

Due to the compatibility problem noted above, this version of the API
should not be used in new code.

 -- C Function: int PyThread_create_key ()
     ' Part of the *note Stable ABI: 556.'

 -- C Function: void PyThread_delete_key (int key)
     ' Part of the *note Stable ABI: 556.'

 -- C Function: int PyThread_set_key_value (int key, void *value)
     ' Part of the *note Stable ABI: 556.'

 -- C Function: void *PyThread_get_key_value (int key)
     ' Part of the *note Stable ABI: 556.'

 -- C Function: void PyThread_delete_key_value (int key)
     ' Part of the *note Stable ABI: 556.'

 -- C Function: void PyThread_ReInitTLS ()
     ' Part of the *note Stable ABI: 556.'


File: python.info,  Node: Synchronization Primitives<2>,  Next: Operating System Thread APIs,  Prev: Thread Local Storage Support,  Up: Initialization Finalization and Threads

7.9.12 Synchronization Primitives
---------------------------------

The C-API provides a basic mutual exclusion lock.

 -- C Type: type PyMutex

     A mutual exclusion lock.  The ‘PyMutex’ should be initialized to
     zero to represent the unlocked state.  For example:

          PyMutex mutex = {0};

     Instances of ‘PyMutex’ should not be copied or moved.  Both the
     contents and address of a ‘PyMutex’ are meaningful, and it must
     remain at a fixed, writable location in memory.

          Note: A ‘PyMutex’ currently occupies one byte, but the size
          should be considered unstable.  The size may change in future
          Python releases without a deprecation period.

     Added in version 3.13.

 -- C Function: void PyMutex_Lock (PyMutex *m)

     Lock mutex 'm'.  If another thread has already locked it, the
     calling thread will block until the mutex is unlocked.  While
     blocked, the thread will temporarily release the *note GIL: 159. if
     it is held.

     Added in version 3.13.

 -- C Function: void PyMutex_Unlock (PyMutex *m)

     Unlock mutex 'm'.  The mutex must be locked — otherwise, the
     function will issue a fatal error.

     Added in version 3.13.

* Menu:

* Python Critical Section API::
* Legacy Locking APIs::


File: python.info,  Node: Python Critical Section API,  Next: Legacy Locking APIs,  Up: Synchronization Primitives<2>

7.9.12.1 Python Critical Section API
....................................

The critical section API provides a deadlock avoidance layer on top of
per-object locks for *note free-threaded: 15b3. CPython.  They are
intended to replace reliance on the *note global interpreter lock: 148,
and are no-ops in versions of Python with the global interpreter lock.

Critical sections are intended to be used for custom types implemented
in C-API extensions.  They should generally not be used with built-in
types like *note list: 614. and *note dict: 256. because their public
C-APIs already use critical sections internally, with the notable
exception of *note PyDict_Next(): 171b, which requires critical section
to be acquired externally.

Critical sections avoid deadlocks by implicitly suspending active
critical sections, hence, they do not provide exclusive access such as
provided by traditional locks like *note PyMutex: 15b.  When a critical
section is started, the per-object lock for the object is acquired.  If
the code executed inside the critical section calls C-API functions then
it can suspend the critical section thereby releasing the per-object
lock, so other threads can acquire the per-object lock for the same
object.

The functions and structs used by the macros are exposed for cases where
C macros are not available.  They should only be used as in the given
macro expansions.  Note that the sizes and contents of the structures
may change in future Python versions.

     Note: Operations that need to lock two objects at once must use
     *note Py_BEGIN_CRITICAL_SECTION2: 51f3.  You 'cannot' use nested
     critical sections to lock more than one object at once, because the
     inner critical section may suspend the outer critical sections.
     This API does not provide a way to lock more than two objects at
     once.

Example usage:

     static PyObject *
     set_field(MyObject *self, PyObject *value)
     {
        Py_BEGIN_CRITICAL_SECTION(self);
        Py_SETREF(self->field, Py_XNewRef(value));
        Py_END_CRITICAL_SECTION();
        Py_RETURN_NONE;
     }

In the above example, *note Py_SETREF: 57c. calls *note Py_DECREF: 572,
which can call arbitrary code through an object’s deallocation function.
The critical section API avoids potential deadlocks due to reentrancy
and lock ordering by allowing the runtime to temporarily suspend the
critical section if the code triggered by the finalizer blocks and calls
*note PyEval_SaveThread(): 3ab.

 -- C Macro: Py_BEGIN_CRITICAL_SECTION (op)

     Acquires the per-object lock for the object 'op' and begins a
     critical section.

     In the free-threaded build, this macro expands to:

          {
              PyCriticalSection _py_cs;
              PyCriticalSection_Begin(&_py_cs, (PyObject*)(op))

     In the default build, this macro expands to ‘{’.

     Added in version 3.13.

 -- C Macro: Py_END_CRITICAL_SECTION ()

     Ends the critical section and releases the per-object lock.

     In the free-threaded build, this macro expands to:

              PyCriticalSection_End(&_py_cs);
          }

     In the default build, this macro expands to ‘}’.

     Added in version 3.13.

 -- C Macro: Py_BEGIN_CRITICAL_SECTION2 (a, b)

     Acquires the per-objects locks for the objects 'a' and 'b' and
     begins a critical section.  The locks are acquired in a consistent
     order (lowest address first) to avoid lock ordering deadlocks.

     In the free-threaded build, this macro expands to:

          {
              PyCriticalSection2 _py_cs2;
              PyCriticalSection2_Begin(&_py_cs2, (PyObject*)(a), (PyObject*)(b))

     In the default build, this macro expands to ‘{’.

     Added in version 3.13.

 -- C Macro: Py_END_CRITICAL_SECTION2 ()

     Ends the critical section and releases the per-object locks.

     In the free-threaded build, this macro expands to:

              PyCriticalSection2_End(&_py_cs2);
          }

     In the default build, this macro expands to ‘}’.

     Added in version 3.13.


File: python.info,  Node: Legacy Locking APIs,  Prev: Python Critical Section API,  Up: Synchronization Primitives<2>

7.9.12.2 Legacy Locking APIs
............................

These APIs are obsolete since Python 3.13 with the introduction of *note
PyMutex: 15b.

Changed in version 3.15: These APIs are now a simple wrapper around
‘PyMutex’.

 -- C Type: type PyThread_type_lock

     A pointer to a mutual exclusion lock.

 -- C Type: type PyLockStatus

     The result of acquiring a lock with a timeout.

      -- C Enumerator: enumerator PY_LOCK_FAILURE

          Failed to acquire the lock.

      -- C Enumerator: enumerator PY_LOCK_ACQUIRED

          The lock was successfully acquired.

      -- C Enumerator: enumerator PY_LOCK_INTR

          The lock was interrupted by a signal.

 -- C Function: *note PyThread_type_lock: 51f7. PyThread_allocate_lock
          (void)
     ' Part of the *note Stable ABI: 556.'  Allocate a new lock.

     On success, this function returns a lock; on failure, this function
     returns ‘0’ without an exception set.

     The caller does not need to hold the *note GIL: 159.

     Changed in version 3.15: This function now always uses *note
     PyMutex: 15b.  In prior versions, this would use a lock provided by
     the operating system.

 -- C Function: void PyThread_free_lock (PyThread_type_lock lock)
     ' Part of the *note Stable ABI: 556.'  Destroy 'lock'.  The lock
     should not be held by any thread when calling this.

     The caller does not need to hold the *note GIL: 159.

 -- C Function: *note PyLockStatus: 51f8. PyThread_acquire_lock_timed
          (PyThread_type_lock lock, long long microseconds, int
          intr_flag)
     ' Part of the *note Stable ABI: 556.'  Acquire 'lock' with a
     timeout.

     This will wait for 'microseconds' microseconds to acquire the lock.
     If the timeout expires, this function returns *note
     PY_LOCK_FAILURE: 51f9.  If 'microseconds' is ‘-1’, this will wait
     indefinitely until the lock has been released.

     If 'intr_flag' is ‘1’, acquiring the lock may be interrupted by a
     signal, in which case this function returns *note PY_LOCK_INTR:
     51fb.  Upon interruption, it’s generally expected that the caller
     makes a call to *note Py_MakePendingCalls(): 4df4. to propagate an
     exception to Python code.

     If the lock is successfully acquired, this function returns *note
     PY_LOCK_ACQUIRED: 51fa.

     The caller does not need to hold the *note GIL: 159.

 -- C Function: int PyThread_acquire_lock (PyThread_type_lock lock, int
          waitflag)
     ' Part of the *note Stable ABI: 556.'  Acquire 'lock'.

     If 'waitflag' is ‘1’ and another thread currently holds the lock,
     this function will wait until the lock can be acquired and will
     always return ‘1’.

     If 'waitflag' is ‘0’ and another thread holds the lock, this
     function will not wait and instead return ‘0’.  If the lock is not
     held by any other thread, then this function will acquire it and
     return ‘1’.

     Unlike *note PyThread_acquire_lock_timed(): 4d8f, acquiring the
     lock cannot be interrupted by a signal.

     The caller does not need to hold the *note GIL: 159.

 -- C Function: int PyThread_release_lock (PyThread_type_lock lock)
     ' Part of the *note Stable ABI: 556.'  Release 'lock'.  If 'lock'
     is not held, then this function issues a fatal error.

     The caller does not need to hold the *note GIL: 159.


File: python.info,  Node: Operating System Thread APIs,  Prev: Synchronization Primitives<2>,  Up: Initialization Finalization and Threads

7.9.13 Operating System Thread APIs
-----------------------------------

 -- C Macro: PYTHREAD_INVALID_THREAD_ID

     Sentinel value for an invalid thread ID.

     This is currently equivalent to ‘(unsigned long)-1’.

 -- C Function: unsigned long PyThread_start_new_thread (void
          (*func)(void*), void *arg)
     ' Part of the *note Stable ABI: 556.'  Start function 'func' in a
     new thread with argument 'arg'.  The resulting thread is not
     intended to be joined.

     'func' must not be ‘NULL’, but 'arg' may be ‘NULL’.

     On success, this function returns the identifier of the new thread;
     on failure, this returns *note PYTHREAD_INVALID_THREAD_ID: 51fd.

     The caller does not need to hold the *note GIL: 159.

 -- C Function: unsigned long PyThread_get_thread_ident (void)
     ' Part of the *note Stable ABI: 556.'  Return the identifier of the
     current thread, which will never be zero.

     This function cannot fail, and the caller does not need to hold the
     *note GIL: 159.

     See also
     ........

     *note threading.get_ident(): 119e.

 -- C Function: *note PyObject: 33a. *PyThread_GetInfo (void)
     ' Part of the *note Stable ABI: 556. since version 3.3.'  Get
     general information about the current thread in the form of a *note
     struct sequence: 1204. object.  This information is accessible as
     *note sys.thread_info: 1194. in Python.

     On success, this returns a new *note strong reference: 33e. to the
     thread information; on failure, this returns ‘NULL’ with an
     exception set.

     The caller must hold the *note GIL: 159.

 -- C Macro: PY_HAVE_THREAD_NATIVE_ID

     This macro is defined when the system supports native thread IDs.

 -- C Function: unsigned long PyThread_get_thread_native_id (void)
     ' Part of the *note Stable ABI: 556. on platforms with native
     thread IDs.'  Get the native identifier of the current thread as it
     was assigned by the operating system’s kernel, which will never be
     less than zero.

     This function is only available when *note
     PY_HAVE_THREAD_NATIVE_ID: 51fe. is defined.

     This function cannot fail, and the caller does not need to hold the
     *note GIL: 159.

     See also
     ........

     *note threading.get_native_id(): a4b.

 -- C Function: void PyThread_exit_thread (void)
     ' Part of the *note Stable ABI: 556.'  Terminate the current
     thread.  This function is generally considered unsafe and should be
     avoided.  It is kept solely for backwards compatibility.

     This function is only safe to call if all functions in the full
     call stack are written to safely allow it.

          Warning: If the current system uses POSIX threads (also known
          as “pthreads”), this calls ‘pthread_exit(3)(1)’, which
          attempts to unwind the stack and call C++ destructors on some
          libc implementations.  However, if a ‘noexcept’ function is
          reached, it may terminate the process.  Other systems, such as
          macOS, do unwinding.

          On Windows, this function calls ‘_endthreadex()’, which kills
          the thread without calling C++ destructors.

          In any case, there is a risk of corruption on the thread’s
          stack.

 -- C Function: void PyThread_init_thread (void)
     ' Part of the *note Stable ABI: 556.'  Initialize ‘PyThread*’ APIs.
     Python executes this function automatically, so there’s little need
     to call it from an extension module.

 -- C Function: int PyThread_set_stacksize (size_t size)
     ' Part of the *note Stable ABI: 556.'  Set the stack size of the
     current thread to 'size' bytes.

     This function returns ‘0’ on success, ‘-1’ if 'size' is invalid, or
     ‘-2’ if the system does not support changing the stack size.  This
     function does not set exceptions.

     The caller does not need to hold the *note GIL: 159.

 -- C Function: size_t PyThread_get_stacksize (void)
     ' Part of the *note Stable ABI: 556.'  Return the stack size of the
     current thread in bytes, or ‘0’ if the system’s default stack size
     is in use.

     The caller does not need to hold the *note GIL: 159.

   ---------- Footnotes ----------

   (1) https://manpages.debian.org/pthread_exit(3)


File: python.info,  Node: Python Initialization Configuration,  Next: Memory Management,  Prev: Initialization Finalization and Threads,  Up: Python/C API Reference Manual

7.10 Python Initialization Configuration
========================================

Added in version 3.8.

Python can be initialized with *note Py_InitializeFromConfig(): 3c8. and
the *note PyConfig: 3a9. structure.  It can be preinitialized with *note
Py_PreInitialize(): 3ee. and the *note PyPreConfig: 9b7. structure.

There are two kinds of configuration:

   * The *note Python Configuration: 51b8. can be used to build a
     customized Python which behaves as the regular Python.  For
     example, environment variables and command line arguments are used
     to configure Python.

   * The *note Isolated Configuration: 5202. can be used to embed Python
     into an application.  It isolates Python from the system.  For
     example, environment variables are ignored, the LC_CTYPE locale is
     left unchanged and no signal handler is registered.

The *note Py_RunMain(): 9d0. function can be used to write a customized
Python program.

See also *note Initialization, Finalization, and Threads: 51aa.

See also
........

PEP 587(1) “Python Initialization Configuration”.

* Menu:

* Example: Example<17>.
* PyWideStringList::
* PyStatus::
* PyPreConfig::
* Preinitialize Python with PyPreConfig::
* PyConfig::
* Initialization with PyConfig::
* Isolated Configuration::
* Python Configuration::
* Python Path Configuration::
* Py_GetArgcArgv(): Py_GetArgcArgv.
* Multi-Phase Initialization Private Provisional API::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0587/


File: python.info,  Node: Example<17>,  Next: PyWideStringList,  Up: Python Initialization Configuration

7.10.1 Example
--------------

Example of customized Python always running in isolated mode:

     int main(int argc, char **argv)
     {
         PyStatus status;

         PyConfig config;
         PyConfig_InitPythonConfig(&config);
         config.isolated = 1;

         /* Decode command line arguments.
            Implicitly preinitialize Python (in isolated mode). */
         status = PyConfig_SetBytesArgv(&config, argc, argv);
         if (PyStatus_Exception(status)) {
             goto exception;
         }

         status = Py_InitializeFromConfig(&config);
         if (PyStatus_Exception(status)) {
             goto exception;
         }
         PyConfig_Clear(&config);

         return Py_RunMain();

     exception:
         PyConfig_Clear(&config);
         if (PyStatus_IsExit(status)) {
             return status.exitcode;
         }
         /* Display the error message and exit the process with
            non-zero exit code */
         Py_ExitStatusException(status);
     }


File: python.info,  Node: PyWideStringList,  Next: PyStatus,  Prev: Example<17>,  Up: Python Initialization Configuration

7.10.2 PyWideStringList
-----------------------

 -- C Type: type PyWideStringList

     List of ‘wchar_t*’ strings.

     If 'length' is non-zero, 'items' must be non-‘NULL’ and all strings
     must be non-‘NULL’.

     Methods:

      -- C Function: *note PyStatus: 9b8. PyWideStringList_Append
               (PyWideStringList *list, const wchar_t *item)

          Append 'item' to 'list'.

          Python must be preinitialized to call this function.

      -- C Function: *note PyStatus: 9b8. PyWideStringList_Insert
               (PyWideStringList *list, Py_ssize_t index, const wchar_t
               *item)

          Insert 'item' into 'list' at 'index'.

          If 'index' is greater than or equal to 'list' length, append
          'item' to 'list'.

          'index' must be greater than or equal to ‘0’.

          Python must be preinitialized to call this function.

     Structure fields:

      -- C Member: *note Py_ssize_t: a6e. length

          List length.

      -- C Member: wchar_t **items

          List items.


File: python.info,  Node: PyStatus,  Next: PyPreConfig,  Prev: PyWideStringList,  Up: Python Initialization Configuration

7.10.3 PyStatus
---------------

 -- C Type: type PyStatus

     Structure to store an initialization function status: success,
     error or exit.

     For an error, it can store the C function name which created the
     error.

     Structure fields:

      -- C Member: int exitcode

          Exit code.  Argument passed to ‘exit()’.

      -- C Member: const char *err_msg

          Error message.

      -- C Member: const char *func

          Name of the function which created an error, can be ‘NULL’.

     Functions to create a status:

      -- C Function: *note PyStatus: 9b8. PyStatus_Ok (void)

          Success.

      -- C Function: *note PyStatus: 9b8. PyStatus_Error (const char
               *err_msg)

          Initialization error with a message.

          'err_msg' must not be ‘NULL’.

      -- C Function: *note PyStatus: 9b8. PyStatus_NoMemory (void)

          Memory allocation failure (out of memory).

      -- C Function: *note PyStatus: 9b8. PyStatus_Exit (int exitcode)

          Exit Python with the specified exit code.

     Functions to handle a status:

      -- C Function: int PyStatus_Exception (PyStatus status)

          Is the status an error or an exit?  If true, the exception
          must be handled; by calling *note Py_ExitStatusException():
          9cd. for example.

      -- C Function: int PyStatus_IsError (PyStatus status)

          Is the result an error?

      -- C Function: int PyStatus_IsExit (PyStatus status)

          Is the result an exit?

      -- C Function: void Py_ExitStatusException (PyStatus status)

          Call ‘exit(exitcode)’ if 'status' is an exit.  Print the error
          message and exit with a non-zero exit code if 'status' is an
          error.  Must only be called if ‘PyStatus_Exception(status)’ is
          non-zero.

     Note: Internally, Python uses macros which set ‘PyStatus.func’,
     whereas functions to create a status set ‘func’ to ‘NULL’.

Example:

     PyStatus alloc(void **ptr, size_t size)
     {
         *ptr = PyMem_RawMalloc(size);
         if (*ptr == NULL) {
             return PyStatus_NoMemory();
         }
         return PyStatus_Ok();
     }

     int main(int argc, char **argv)
     {
         void *ptr;
         PyStatus status = alloc(&ptr, 16);
         if (PyStatus_Exception(status)) {
             Py_ExitStatusException(status);
         }
         PyMem_Free(ptr);
         return 0;
     }


File: python.info,  Node: PyPreConfig,  Next: Preinitialize Python with PyPreConfig,  Prev: PyStatus,  Up: Python Initialization Configuration

7.10.4 PyPreConfig
------------------

 -- C Type: type PyPreConfig

     Structure used to preinitialize Python.

     Function to initialize a preconfiguration:

      -- C Function: void PyPreConfig_InitPythonConfig (PyPreConfig
               *preconfig)

          Initialize the preconfiguration with *note Python
          Configuration: 51b8.

      -- C Function: void PyPreConfig_InitIsolatedConfig (PyPreConfig
               *preconfig)

          Initialize the preconfiguration with *note Isolated
          Configuration: 5202.

     Structure fields:

      -- C Member: int allocator

          Name of the Python memory allocators:

             * ‘PYMEM_ALLOCATOR_NOT_SET’ (‘0’): don’t change memory
               allocators (use defaults).

             * ‘PYMEM_ALLOCATOR_DEFAULT’ (‘1’): *note default memory
               allocators: 1ef3.

             * ‘PYMEM_ALLOCATOR_DEBUG’ (‘2’): *note default memory
               allocators: 1ef3. with *note debug hooks: 1ef6.

             * ‘PYMEM_ALLOCATOR_MALLOC’ (‘3’): use ‘malloc()’ of the C
               library.

             * ‘PYMEM_ALLOCATOR_MALLOC_DEBUG’ (‘4’): force usage of
               ‘malloc()’ with *note debug hooks: 1ef6.

             * ‘PYMEM_ALLOCATOR_PYMALLOC’ (‘5’): *note Python pymalloc
               memory allocator: d37.

             * ‘PYMEM_ALLOCATOR_PYMALLOC_DEBUG’ (‘6’): *note Python
               pymalloc memory allocator: d37. with *note debug hooks:
               1ef6.

             * ‘PYMEM_ALLOCATOR_MIMALLOC’ (‘6’): use ‘mimalloc’, a fast
               malloc replacement.

             * ‘PYMEM_ALLOCATOR_MIMALLOC_DEBUG’ (‘7’): use ‘mimalloc’, a
               fast malloc replacement with *note debug hooks: 1ef6.

          ‘PYMEM_ALLOCATOR_PYMALLOC’ and
          ‘PYMEM_ALLOCATOR_PYMALLOC_DEBUG’ are not supported if Python
          is *note configured using -without-pymalloc: 1f55.

          ‘PYMEM_ALLOCATOR_MIMALLOC’ and
          ‘PYMEM_ALLOCATOR_MIMALLOC_DEBUG’ are not supported if Python
          is *note configured using -without-mimalloc: 1f54. or if the
          underlying atomic support isn’t available.

          See *note Memory Management: 520d.

          Default: ‘PYMEM_ALLOCATOR_NOT_SET’.

      -- C Member: int configure_locale

          Set the LC_CTYPE locale to the user preferred locale.

          If equals to ‘0’, set *note coerce_c_locale: 520f. and *note
          coerce_c_locale_warn: 5210. members to ‘0’.

          See the *note locale encoding: 242.

          Default: ‘1’ in Python config, ‘0’ in isolated config.

      -- C Member: int coerce_c_locale

          If equals to ‘2’, coerce the C locale.

          If equals to ‘1’, read the LC_CTYPE locale to decide if it
          should be coerced.

          See the *note locale encoding: 242.

          Default: ‘-1’ in Python config, ‘0’ in isolated config.

      -- C Member: int coerce_c_locale_warn

          If non-zero, emit a warning if the C locale is coerced.

          Default: ‘-1’ in Python config, ‘0’ in isolated config.

      -- C Member: int dev_mode

          *note Python Development Mode: 1f8.: see *note
          PyConfig.dev_mode: 5212.

          Default: ‘-1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: int isolated

          Isolated mode: see *note PyConfig.isolated: 3e7.

          Default: ‘0’ in Python mode, ‘1’ in isolated mode.

      -- C Member: int legacy_windows_fs_encoding

          If non-zero:

             * Set *note PyPreConfig.utf8_mode: 3ed. to ‘0’,

             * Set *note PyConfig.filesystem_encoding: 3eb. to ‘"mbcs"’,

             * Set *note PyConfig.filesystem_errors: 3ec. to
               ‘"replace"’.

          Initialized from the *note PYTHONLEGACYWINDOWSFSENCODING: 2af.
          environment variable value.

          Only available on Windows.  ‘#ifdef MS_WINDOWS’ macro can be
          used for Windows specific code.

          Default: ‘0’.

      -- C Member: int parse_argv

          If non-zero, *note Py_PreInitializeFromArgs(): 9ce. and *note
          Py_PreInitializeFromBytesArgs(): 9cf. parse their ‘argv’
          argument the same way the regular Python parses command line
          arguments: see *note Command Line Arguments: 1042.

          Default: ‘1’ in Python config, ‘0’ in isolated config.

      -- C Member: int use_environment

          Use *note environment variables: 5f4.?  See *note
          PyConfig.use_environment: 3dc.

          Default: ‘1’ in Python config and ‘0’ in isolated config.

      -- C Member: int utf8_mode

          If non-zero, enable the *note Python UTF-8 Mode: 659.

          Set to ‘0’ or ‘1’ by the *note -X utf8: 176. command line
          option and the *note PYTHONUTF8: aee. environment variable.

          Also set to ‘1’ if the ‘LC_CTYPE’ locale is ‘C’ or ‘POSIX’.

          Default: ‘-1’ in Python config and ‘0’ in isolated config.


File: python.info,  Node: Preinitialize Python with PyPreConfig,  Next: PyConfig,  Prev: PyPreConfig,  Up: Python Initialization Configuration

7.10.5 Preinitialize Python with PyPreConfig
--------------------------------------------

The preinitialization of Python:

   * Set the Python memory allocators (*note PyPreConfig.allocator:
     520c.)

   * Configure the LC_CTYPE locale (*note locale encoding: 242.)

   * Set the *note Python UTF-8 Mode: 659. (*note PyPreConfig.utf8_mode:
     3ed.)

The current preconfiguration (‘PyPreConfig’ type) is stored in
‘_PyRuntime.preconfig’.

Functions to preinitialize Python:

 -- C Function: *note PyStatus: 9b8. Py_PreInitialize (const PyPreConfig
          *preconfig)

     Preinitialize Python from 'preconfig' preconfiguration.

     'preconfig' must not be ‘NULL’.

 -- C Function: *note PyStatus: 9b8. Py_PreInitializeFromBytesArgs
          (const PyPreConfig *preconfig, int argc, char *const *argv)

     Preinitialize Python from 'preconfig' preconfiguration.

     Parse 'argv' command line arguments (bytes strings) if *note
     parse_argv: 5214. of 'preconfig' is non-zero.

     'preconfig' must not be ‘NULL’.

 -- C Function: *note PyStatus: 9b8. Py_PreInitializeFromArgs (const
          PyPreConfig *preconfig, int argc, wchar_t *const *argv)

     Preinitialize Python from 'preconfig' preconfiguration.

     Parse 'argv' command line arguments (wide strings) if *note
     parse_argv: 5214. of 'preconfig' is non-zero.

     'preconfig' must not be ‘NULL’.

The caller is responsible to handle exceptions (error or exit) using
*note PyStatus_Exception(): 9c4. and *note Py_ExitStatusException():
9cd.

For *note Python Configuration: 51b8. (*note
PyPreConfig_InitPythonConfig(): 9c2.), if Python is initialized with
command line arguments, the command line arguments must also be passed
to preinitialize Python, since they have an effect on the
pre-configuration like encodings.  For example, the *note -X utf8: 176.
command line option enables the *note Python UTF-8 Mode: 659.

‘PyMem_SetAllocator()’ can be called after *note Py_PreInitialize():
3ee. and before *note Py_InitializeFromConfig(): 3c8. to install a
custom memory allocator.  It can be called before ‘Py_PreInitialize()’
if *note PyPreConfig.allocator: 520c. is set to
‘PYMEM_ALLOCATOR_NOT_SET’.

Python memory allocation functions like *note PyMem_RawMalloc(): 393.
must not be used before the Python preinitialization, whereas calling
directly ‘malloc()’ and ‘free()’ is always safe.  *note
Py_DecodeLocale(): be6. must not be called before the Python
preinitialization.

Example using the preinitialization to enable the *note Python UTF-8
Mode: 659.:

     PyStatus status;
     PyPreConfig preconfig;
     PyPreConfig_InitPythonConfig(&preconfig);

     preconfig.utf8_mode = 1;

     status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }

     /* at this point, Python speaks UTF-8 */

     Py_Initialize();
     /* ... use Python API here ... */
     Py_Finalize();


File: python.info,  Node: PyConfig,  Next: Initialization with PyConfig,  Prev: Preinitialize Python with PyPreConfig,  Up: Python Initialization Configuration

7.10.6 PyConfig
---------------

 -- C Type: type PyConfig

     Structure containing most parameters to configure Python.

     When done, the *note PyConfig_Clear(): 9ba. function must be used
     to release the configuration memory.

     Structure methods:

      -- C Function: void PyConfig_InitPythonConfig (PyConfig *config)

          Initialize configuration with the *note Python Configuration:
          51b8.

      -- C Function: void PyConfig_InitIsolatedConfig (PyConfig *config)

          Initialize configuration with the *note Isolated
          Configuration: 5202.

      -- C Function: *note PyStatus: 9b8. PyConfig_SetString (PyConfig
               *config, wchar_t *const *config_str, const wchar_t *str)

          Copy the wide character string 'str' into ‘*config_str’.

          *note Preinitialize Python: 3fa2. if needed.

      -- C Function: *note PyStatus: 9b8. PyConfig_SetBytesString
               (PyConfig *config, wchar_t *const *config_str, const char
               *str)

          Decode 'str' using *note Py_DecodeLocale(): be6. and set the
          result into ‘*config_str’.

          *note Preinitialize Python: 3fa2. if needed.

      -- C Function: *note PyStatus: 9b8. PyConfig_SetArgv (PyConfig
               *config, int argc, wchar_t *const *argv)

          Set command line arguments (*note argv: 3c6. member of
          'config') from the 'argv' list of wide character strings.

          *note Preinitialize Python: 3fa2. if needed.

      -- C Function: *note PyStatus: 9b8. PyConfig_SetBytesArgv
               (PyConfig *config, int argc, char *const *argv)

          Set command line arguments (*note argv: 3c6. member of
          'config') from the 'argv' list of bytes strings.  Decode bytes
          using *note Py_DecodeLocale(): be6.

          *note Preinitialize Python: 3fa2. if needed.

      -- C Function: *note PyStatus: 9b8. PyConfig_SetWideStringList
               (PyConfig *config, PyWideStringList *list, Py_ssize_t
               length, wchar_t **items)

          Set the list of wide strings 'list' to 'length' and 'items'.

          *note Preinitialize Python: 3fa2. if needed.

      -- C Function: *note PyStatus: 9b8. PyConfig_Read (PyConfig
               *config)

          Read all Python configuration.

          Fields which are already initialized are left unchanged.

          Fields for *note path configuration: 8b5. are no longer
          calculated or modified when calling this function, as of
          Python 3.11.

          The *note PyConfig_Read(): 793. function only parses *note
          PyConfig.argv: 3c6. arguments once: *note PyConfig.parse_argv:
          1a98. is set to ‘2’ after arguments are parsed.  Since Python
          arguments are stripped from ‘PyConfig.argv’, parsing arguments
          twice would parse the application options as Python options.

          *note Preinitialize Python: 3fa2. if needed.

          Changed in version 3.10: The *note PyConfig.argv: 3c6.
          arguments are now only parsed once, *note PyConfig.parse_argv:
          1a98. is set to ‘2’ after arguments are parsed, and arguments
          are only parsed if ‘PyConfig.parse_argv’ equals ‘1’.

          Changed in version 3.11: *note PyConfig_Read(): 793. no longer
          calculates all paths, and so fields listed under *note Python
          Path Configuration: 8b5. may no longer be updated until *note
          Py_InitializeFromConfig(): 3c8. is called.

      -- C Function: void PyConfig_Clear (PyConfig *config)

          Release configuration memory.

     Most ‘PyConfig’ methods *note preinitialize Python: 3fa2. if
     needed.  In that case, the Python preinitialization configuration
     (*note PyPreConfig: 9b7.) is based on the *note PyConfig: 3a9.  If
     configuration fields which are in common with ‘PyPreConfig’ are
     tuned, they must be set before calling a ‘PyConfig’ method:

        * *note PyConfig.dev_mode: 5212.

        * *note PyConfig.isolated: 3e7.

        * *note PyConfig.parse_argv: 1a98.

        * *note PyConfig.use_environment: 3dc.

     Moreover, if *note PyConfig_SetArgv(): 9bd. or *note
     PyConfig_SetBytesArgv(): 9be. is used, this method must be called
     before other methods, since the preinitialization configuration
     depends on command line arguments (if *note parse_argv: 1a98. is
     non-zero).

     The caller of these methods is responsible to handle exceptions
     (error or exit) using ‘PyStatus_Exception()’ and
     ‘Py_ExitStatusException()’.

     Structure fields:

      -- C Member: *note PyWideStringList: 9b9. argv

          Set *note sys.argv: 12ab. command line arguments based on
          *note argv: 3c6.  These parameters are similar to those passed
          to the program’s ‘main()’ function with the difference that
          the first entry should refer to the script file to be executed
          rather than the executable hosting the Python interpreter.  If
          there isn’t a script that will be run, the first entry in
          ‘argv’ can be an empty string.

          Set *note parse_argv: 1a98. to ‘1’ to parse *note argv: 3c6.
          the same way the regular Python parses Python command line
          arguments and then to strip Python arguments from ‘argv’.

          If *note argv: 3c6. is empty, an empty string is added to
          ensure that *note sys.argv: 12ab. always exists and is never
          empty.

          Default: ‘NULL’.

          See also the *note orig_argv: 89b. member.

      -- C Member: int safe_path

          If equals to zero, ‘Py_RunMain()’ prepends a potentially
          unsafe path to *note sys.path: 3b7. at startup:

             * If *note argv[0]: 3c6. is equal to ‘L"-m"’ (‘python -m
               module’), prepend the current working directory.

             * If running a script (‘python script.py’), prepend the
               script’s directory.  If it’s a symbolic link, resolve
               symbolic links.

             * Otherwise (‘python -c code’ and ‘python’), prepend an
               empty string, which means the current working directory.

          Set to ‘1’ by the *note -P: 5a7. command line option and the
          *note PYTHONSAFEPATH: 5a8. environment variable.

          Default: ‘0’ in Python config, ‘1’ in isolated config.

          Added in version 3.11.

      -- C Member: wchar_t *base_exec_prefix

          *note sys.base_exec_prefix: 3f1.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.exec_prefix: 5219.

      -- C Member: wchar_t *base_executable

          Python base executable: ‘sys._base_executable’.

          Set by the ‘__PYVENV_LAUNCHER__’ environment variable.

          Set from *note PyConfig.executable: 3a8. if ‘NULL’.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.executable: 3a8.

      -- C Member: wchar_t *base_prefix

          *note sys.base_prefix: 3f2.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.prefix: 521c.

      -- C Member: int buffered_stdio

          If equals to ‘0’ and *note configure_c_stdio: 521d. is
          non-zero, disable buffering on the C streams stdout and
          stderr.

          Set to ‘0’ by the *note -u: 1b36. command line option and the
          *note PYTHONUNBUFFERED: 1b37. environment variable.

          stdin is always opened in buffered mode.

          Default: ‘1’.

      -- C Member: int bytes_warning

          If equals to ‘1’, issue a warning when comparing *note bytes:
          1c2. or *note bytearray: 2ea. with *note str: 44f, or
          comparing ‘bytes’ with *note int: 257.

          If equal or greater to ‘2’, raise a *note BytesWarning: c43.
          exception in these cases.

          Incremented by the *note -b: 5e6. command line option.

          Default: ‘0’.

      -- C Member: int warn_default_encoding

          If non-zero, emit a *note EncodingWarning: 1ee5. warning when
          *note io.TextIOWrapper: 7bf. uses its default encoding.  See
          *note Opt-in EncodingWarning: 1ef8. for details.

          Default: ‘0’.

          Added in version 3.10.

      -- C Member: int code_debug_ranges

          If equals to ‘0’, disables the inclusion of the end line and
          column mappings in code objects.  Also disables traceback
          printing carets to specific error locations.

          Set to ‘0’ by the *note PYTHONNODEBUGRANGES: 5b9. environment
          variable and by the *note -X no_debug_ranges: 176. command
          line option.

          Default: ‘1’.

          Added in version 3.11.

      -- C Member: wchar_t *check_hash_pycs_mode

          Control the validation behavior of hash-based ‘.pyc’ files:
          value of the *note -check-hash-based-pycs: 1ed9. command line
          option.

          Valid values:

             - ‘L"always"’: Hash the source file for invalidation
               regardless of value of the ‘check_source’ flag.

             - ‘L"never"’: Assume that hash-based pycs always are valid.

             - ‘L"default"’: The ‘check_source’ flag in hash-based pycs
               determines invalidation.

          Default: ‘L"default"’.

          See also PEP 552(1) “Deterministic pycs”.

      -- C Member: int configure_c_stdio

          If non-zero, configure C standard streams:

             * On Windows, set the binary mode (‘O_BINARY’) on stdin,
               stdout and stderr.

             * If *note buffered_stdio: 3e2. equals zero, disable
               buffering of stdin, stdout and stderr streams.

             * If *note interactive: 3d0. is non-zero, enable stream
               buffering on stdin and stdout (only stdout on Windows).

          Default: ‘1’ in Python config, ‘0’ in isolated config.

      -- C Member: int dev_mode

          If non-zero, enable the *note Python Development Mode: 1f8.

          Set to ‘1’ by the *note -X dev: 176. option and the *note
          PYTHONDEVMODE: b06. environment variable.

          Default: ‘-1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: int dump_refs

          Dump Python references?

          If non-zero, dump all objects which are still alive at exit.

          Set to ‘1’ by the *note PYTHONDUMPREFS: 9b1. environment
          variable.

          Needs a special build of Python with the ‘Py_TRACE_REFS’ macro
          defined: see the *note configure -with-trace-refs option: 398.

          Default: ‘0’.

      -- C Member: wchar_t *exec_prefix

          The site-specific directory prefix where the
          platform-dependent Python files are installed: *note
          sys.exec_prefix: 3b5.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.base_exec_prefix: 5218.

      -- C Member: wchar_t *executable

          The absolute path of the executable binary for the Python
          interpreter: *note sys.executable: 3bb.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.base_executable: 521a.

      -- C Member: int faulthandler

          Enable faulthandler?

          If non-zero, call *note faulthandler.enable(): cc4. at
          startup.

          Set to ‘1’ by *note -X faulthandler: 176. and the *note
          PYTHONFAULTHANDLER: 10c3. environment variable.

          Default: ‘-1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: wchar_t *filesystem_encoding

          *note Filesystem encoding: 53e.: *note
          sys.getfilesystemencoding(): c7a.

          On macOS, Android and VxWorks: use ‘"utf-8"’ by default.

          On Windows: use ‘"utf-8"’ by default, or ‘"mbcs"’ if *note
          legacy_windows_fs_encoding: 3e9. of *note PyPreConfig: 9b7. is
          non-zero.

          Default encoding on other platforms:

             * ‘"utf-8"’ if *note PyPreConfig.utf8_mode: 3ed. is
               non-zero.

             * ‘"ascii"’ if Python detects that ‘nl_langinfo(CODESET)’
               announces the ASCII encoding, whereas the ‘mbstowcs()’
               function decodes from a different encoding (usually
               Latin1).

             * ‘"utf-8"’ if ‘nl_langinfo(CODESET)’ returns an empty
               string.

             * Otherwise, use the *note locale encoding: 242.:
               ‘nl_langinfo(CODESET)’ result.

          At Python startup, the encoding name is normalized to the
          Python codec name.  For example, ‘"ANSI_X3.4-1968"’ is
          replaced with ‘"ascii"’.

          See also the *note filesystem_errors: 3ec. member.

      -- C Member: wchar_t *filesystem_errors

          *note Filesystem error handler: 53e.: *note
          sys.getfilesystemencodeerrors(): d0d.

          On Windows: use ‘"surrogatepass"’ by default, or ‘"replace"’
          if *note legacy_windows_fs_encoding: 3e9. of *note
          PyPreConfig: 9b7. is non-zero.

          On other platforms: use ‘"surrogateescape"’ by default.

          Supported error handlers:

             * ‘"strict"’

             * ‘"surrogateescape"’

             * ‘"surrogatepass"’ (only supported with the UTF-8
               encoding)

          See also the *note filesystem_encoding: 3eb. member.

      -- C Member: unsigned long hash_seed

      -- C Member: int use_hash_seed

          Randomized hash function seed.

          If *note use_hash_seed: 3e4. is zero, a seed is chosen
          randomly at Python startup, and *note hash_seed: 3e5. is
          ignored.

          Set by the *note PYTHONHASHSEED: 10bb. environment variable.

          Default 'use_hash_seed' value: ‘-1’ in Python mode, ‘0’ in
          isolated mode.

      -- C Member: wchar_t *home

          Set the default Python “home” directory, that is, the location
          of the standard Python libraries (see *note PYTHONHOME: 3bf.).

          Set by the *note PYTHONHOME: 3bf. environment variable.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. input.

      -- C Member: int import_time

          If non-zero, profile import time.

          Set the ‘1’ by the *note -X importtime: 176. option and the
          *note PYTHONPROFILEIMPORTTIME: b0e. environment variable.

          Default: ‘0’.

      -- C Member: int inspect

          Enter interactive mode after executing a script or a command.

          If greater than ‘0’, enable inspect: when a script is passed
          as first argument or the -c option is used, enter interactive
          mode after executing the script or the command, even when
          *note sys.stdin: 540. does not appear to be a terminal.

          Incremented by the *note -i: 152a. command line option.  Set
          to ‘1’ if the *note PYTHONINSPECT: 1529. environment variable
          is non-empty.

          Default: ‘0’.

      -- C Member: int install_signal_handlers

          Install Python signal handlers?

          Default: ‘1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: int interactive

          If greater than ‘0’, enable the interactive mode (REPL).

          Incremented by the *note -i: 152a. command line option.

          Default: ‘0’.

      -- C Member: int int_max_str_digits

          Configures the *note integer string conversion length
          limitation: 5f8.  An initial value of ‘-1’ means the value
          will be taken from the command line or environment or
          otherwise default to 4300 (*note
          sys.int_info.default_max_str_digits: 2434.).  A value of ‘0’
          disables the limitation.  Values greater than zero but less
          than 640 (*note sys.int_info.str_digits_check_threshold:
          45eb.) are unsupported and will produce an error.

          Configured by the *note -X int_max_str_digits: 176. command
          line flag or the *note PYTHONINTMAXSTRDIGITS: 18dd.
          environment variable.

          Default: ‘-1’ in Python mode.  4300 (*note
          sys.int_info.default_max_str_digits: 2434.) in isolated mode.

          Added in version 3.12.

      -- C Member: int cpu_count

          If the value of *note cpu_count: 5225. is not ‘-1’ then it
          will override the return values of *note os.cpu_count(): 1c5,
          *note os.process_cpu_count(): 1c4, and *note
          multiprocessing.cpu_count(): fa8.

          Configured by the ‘-X cpu_count=N|DEFAULT’ command line flag
          or the *note PYTHON_CPU_COUNT: 210. environment variable.

          Default: ‘-1’.

          Added in version 3.13.

      -- C Member: int isolated

          If greater than ‘0’, enable isolated mode:

             * Set *note safe_path: 776. to ‘1’: don’t prepend a
               potentially unsafe path to *note sys.path: 3b7. at Python
               startup, such as the current directory, the script’s
               directory or an empty string.

             * Set *note use_environment: 3dc. to ‘0’: ignore ‘PYTHON’
               environment variables.

             * Set *note user_site_directory: 3e0. to ‘0’: don’t add the
               user site directory to *note sys.path: 3b7.

             * Python REPL doesn’t import *note readline: ba. nor enable
               default readline configuration on interactive prompts.

          Set to ‘1’ by the *note -I: 968. command line option.

          Default: ‘0’ in Python mode, ‘1’ in isolated mode.

          See also the *note Isolated Configuration: 5202. and *note
          PyPreConfig.isolated: 5213.

      -- C Member: int legacy_windows_stdio

          If non-zero, use *note io.FileIO: 1359. instead of
          ‘io._WindowsConsoleIO’ for *note sys.stdin: 540, *note
          sys.stdout: aec. and *note sys.stderr: 943.

          Set to ‘1’ if the *note PYTHONLEGACYWINDOWSSTDIO: c7c.
          environment variable is set to a non-empty string.

          Only available on Windows.  ‘#ifdef MS_WINDOWS’ macro can be
          used for Windows specific code.

          Default: ‘0’.

          See also the PEP 528(2) (Change Windows console encoding to
          UTF-8).

      -- C Member: int malloc_stats

          If non-zero, dump statistics on *note Python pymalloc memory
          allocator: d37. at exit.

          Set to ‘1’ by the *note PYTHONMALLOCSTATS: 1ce8. environment
          variable.

          The option is ignored if Python is *note configured using the
          -without-pymalloc option: 1f55.

          Default: ‘0’.

      -- C Member: wchar_t *platlibdir

          Platform library directory name: *note sys.platlibdir: 942.

          Set by the *note PYTHONPLATLIBDIR: 1aca. environment variable.

          Default: value of the ‘PLATLIBDIR’ macro which is set by the
          *note configure -with-platlibdir option: 1f1d. (default:
          ‘"lib"’, or ‘"DLLs"’ on Windows).

          Part of the *note Python Path Configuration: 8b5. input.

          Added in version 3.9.

          Changed in version 3.11: This macro is now used on Windows to
          locate the standard library extension modules, typically under
          ‘DLLs’.  However, for compatibility, note that this value is
          ignored for any non-standard layouts, including in-tree builds
          and virtual environments.

      -- C Member: wchar_t *pythonpath_env

          Module search paths (*note sys.path: 3b7.) as a string
          separated by ‘DELIM’ (*note os.pathsep: 1eec.).

          Set by the *note PYTHONPATH: 1058. environment variable.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. input.

      -- C Member: *note PyWideStringList: 9b9. module_search_paths

      -- C Member: int module_search_paths_set

          Module search paths: *note sys.path: 3b7.

          If *note module_search_paths_set: 5f2. is equal to ‘0’, *note
          Py_InitializeFromConfig(): 3c8. will replace *note
          module_search_paths: 3a5. and sets ‘module_search_paths_set’
          to ‘1’.

          Default: empty list (‘module_search_paths’) and ‘0’
          (‘module_search_paths_set’).

          Part of the *note Python Path Configuration: 8b5. output.

      -- C Member: int optimization_level

          Compilation optimization level:

             * ‘0’: Peephole optimizer, set ‘__debug__’ to ‘True’.

             * ‘1’: Level 0, remove assertions, set ‘__debug__’ to
               ‘False’.

             * ‘2’: Level 1, strip docstrings.

          Incremented by the *note -O: de3. command line option.  Set to
          the *note PYTHONOPTIMIZE: 1edc. environment variable value.

          Default: ‘0’.

      -- C Member: *note PyWideStringList: 9b9. orig_argv

          The list of the original command line arguments passed to the
          Python executable: *note sys.orig_argv: 846.

          If *note orig_argv: 89b. list is empty and *note argv: 3c6. is
          not a list only containing an empty string, *note
          PyConfig_Read(): 793. copies ‘argv’ into ‘orig_argv’ before
          modifying ‘argv’ (if *note parse_argv: 1a98. is non-zero).

          See also the *note argv: 3c6. member and the *note
          Py_GetArgcArgv(): 1ae8. function.

          Default: empty list.

          Added in version 3.10.

      -- C Member: int parse_argv

          Parse command line arguments?

          If equals to ‘1’, parse *note argv: 3c6. the same way the
          regular Python parses *note command line arguments: 1042, and
          strip Python arguments from ‘argv’.

          The *note PyConfig_Read(): 793. function only parses *note
          PyConfig.argv: 3c6. arguments once: *note PyConfig.parse_argv:
          1a98. is set to ‘2’ after arguments are parsed.  Since Python
          arguments are stripped from ‘PyConfig.argv’, parsing arguments
          twice would parse the application options as Python options.

          Default: ‘1’ in Python mode, ‘0’ in isolated mode.

          Changed in version 3.10: The *note PyConfig.argv: 3c6.
          arguments are now only parsed if *note PyConfig.parse_argv:
          1a98. equals to ‘1’.

      -- C Member: int parser_debug

          Parser debug mode.  If greater than ‘0’, turn on parser
          debugging output (for expert only, depending on compilation
          options).

          Incremented by the *note -d: 1eda. command line option.  Set
          to the *note PYTHONDEBUG: 1edb. environment variable value.

          Needs a *note debug build of Python: 1f9. (the ‘Py_DEBUG’
          macro must be defined).

          Default: ‘0’.

      -- C Member: int pathconfig_warnings

          If non-zero, calculation of path configuration is allowed to
          log warnings into ‘stderr’.  If equals to ‘0’, suppress these
          warnings.

          Default: ‘1’ in Python mode, ‘0’ in isolated mode.

          Part of the *note Python Path Configuration: 8b5. input.

          Changed in version 3.11: Now also applies on Windows.

      -- C Member: wchar_t *prefix

          The site-specific directory prefix where the platform
          independent Python files are installed: *note sys.prefix: 3b9.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. output.

          See also *note PyConfig.base_prefix: 521b.

      -- C Member: wchar_t *program_name

          Program name used to initialize *note executable: 3a8. and in
          early error messages during Python initialization.

             * On macOS, use *note PYTHONEXECUTABLE: 1ef0. environment
               variable if set.

             * If the ‘WITH_NEXT_FRAMEWORK’ macro is defined, use
               ‘__PYVENV_LAUNCHER__’ environment variable if set.

             * Use ‘argv[0]’ of *note argv: 3c6. if available and
               non-empty.

             * Otherwise, use ‘L"python"’ on Windows, or ‘L"python3"’ on
               other platforms.

          Default: ‘NULL’.

          Part of the *note Python Path Configuration: 8b5. input.

      -- C Member: wchar_t *pycache_prefix

          Directory where cached ‘.pyc’ files are written: *note
          sys.pycache_prefix: 9af.

          Set by the *note -X pycache_prefix=PATH: 176. command line
          option and the *note PYTHONPYCACHEPREFIX: 9ae. environment
          variable.  The command-line option takes precedence.

          If ‘NULL’, *note sys.pycache_prefix: 9af. is set to ‘None’.

          Default: ‘NULL’.

      -- C Member: int quiet

          Quiet mode.  If greater than ‘0’, don’t display the copyright
          and version at Python startup in interactive mode.

          Incremented by the *note -q: 15c9. command line option.

          Default: ‘0’.

      -- C Member: wchar_t *run_command

          Value of the *note -c: 5e3. command line option.

          Used by *note Py_RunMain(): 9d0.

          Default: ‘NULL’.

      -- C Member: wchar_t *run_filename

          Filename passed on the command line: trailing command line
          argument without *note -c: 5e3. or *note -m: 5e4.  It is used
          by the *note Py_RunMain(): 9d0. function.

          For example, it is set to ‘script.py’ by the ‘python3
          script.py arg’ command line.

          See also the *note PyConfig.skip_source_first_line: 5229.
          option.

          Default: ‘NULL’.

      -- C Member: wchar_t *run_module

          Value of the *note -m: 5e4. command line option.

          Used by *note Py_RunMain(): 9d0.

          Default: ‘NULL’.

      -- C Member: wchar_t *run_presite

          ‘package.module’ path to module that should be imported before
          ‘site.py’ is run.

          Set by the *note -X presite=package.module: 176. command-line
          option and the *note PYTHON_PRESITE: 1ee6. environment
          variable.  The command-line option takes precedence.

          Needs a *note debug build of Python: 1f9. (the ‘Py_DEBUG’
          macro must be defined).

          Default: ‘NULL’.

      -- C Member: int show_ref_count

          Show total reference count at exit (excluding *note immortal:
          45dd. objects)?

          Set to ‘1’ by *note -X showrefcount: 176. command line option.

          Needs a *note debug build of Python: 1f9. (the ‘Py_REF_DEBUG’
          macro must be defined).

          Default: ‘0’.

      -- C Member: int site_import

          Import the *note site: c7. module at startup?

          If equal to zero, disable the import of the module site and
          the site-dependent manipulations of *note sys.path: 3b7. that
          it entails.

          Also disable these manipulations if the *note site: c7. module
          is explicitly imported later (call *note site.main(): 1ede. if
          you want them to be triggered).

          Set to ‘0’ by the *note -S: 11ec. command line option.

          *note sys.flags.no_site: 68f. is set to the inverted value of
          *note site_import: 3d6.

          Default: ‘1’.

      -- C Member: int skip_source_first_line

          If non-zero, skip the first line of the *note
          PyConfig.run_filename: 51b6. source.

          It allows the usage of non-Unix forms of ‘#!cmd’.  This is
          intended for a DOS specific hack only.

          Set to ‘1’ by the *note -x: 1ee2. command line option.

          Default: ‘0’.

      -- C Member: wchar_t *stdio_encoding

      -- C Member: wchar_t *stdio_errors

          Encoding and encoding errors of *note sys.stdin: 540, *note
          sys.stdout: aec. and *note sys.stderr: 943. (but ‘sys.stderr’
          always uses ‘"backslashreplace"’ error handler).

          Use the *note PYTHONIOENCODING: 1045. environment variable if
          it is non-empty.

          Default encoding:

             * ‘"UTF-8"’ if *note PyPreConfig.utf8_mode: 3ed. is
               non-zero.

             * Otherwise, use the *note locale encoding: 242.

          Default error handler:

             * On Windows: use ‘"surrogateescape"’.

             * ‘"surrogateescape"’ if *note PyPreConfig.utf8_mode: 3ed.
               is non-zero, or if the LC_CTYPE locale is “C” or “POSIX”.

             * ‘"strict"’ otherwise.

          See also *note PyConfig.legacy_windows_stdio: 3a7.

      -- C Member: int tracemalloc

          Enable tracemalloc?

          If non-zero, call *note tracemalloc.start(): 1ee3. at startup.

          Set by *note -X tracemalloc=N: 176. command line option and by
          the *note PYTHONTRACEMALLOC: 1ee4. environment variable.

          Default: ‘-1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: int perf_profiling

          Enable compatibility mode with the perf profiler?

          If non-zero, initialize the perf trampoline.  See *note Python
          support for the Linux perf profiler: 18f. for more
          information.

          Set by *note -X perf: 176. command-line option and by the
          *note PYTHON_PERF_JIT_SUPPORT: 190. environment variable for
          perf support with stack pointers and ‘-X perf_jit’
          command-line option and by the ‘PYTHON_PERF_JIT_SUPPORT’
          environment variable for perf support with DWARF JIT
          information.

          Default: ‘-1’.

          Added in version 3.12.

      -- C Member: int use_environment

          Use *note environment variables: 5f4.?

          If equals to zero, ignore the *note environment variables:
          5f4.

          Set to ‘0’ by the *note -E: 967. environment variable.

          Default: ‘1’ in Python config and ‘0’ in isolated config.

      -- C Member: int user_site_directory

          If non-zero, add the user site directory to *note sys.path:
          3b7.

          Set to ‘0’ by the *note -s: 13db. and *note -I: 968. command
          line options.

          Set to ‘0’ by the *note PYTHONNOUSERSITE: 13dc. environment
          variable.

          Default: ‘1’ in Python mode, ‘0’ in isolated mode.

      -- C Member: int verbose

          Verbose mode.  If greater than ‘0’, print a message each time
          a module is imported, showing the place (filename or built-in
          module) from which it is loaded.

          If greater than or equal to ‘2’, print a message for each file
          that is checked for when searching for a module.  Also
          provides information on module cleanup at exit.

          Incremented by the *note -v: 1473. command line option.

          Set by the *note PYTHONVERBOSE: 1edf. environment variable
          value.

          Default: ‘0’.

      -- C Member: *note PyWideStringList: 9b9. warnoptions

          Options of the *note warnings: 112. module to build warnings
          filters, lowest to highest priority: *note sys.warnoptions:
          3b3.

          The *note warnings: 112. module adds *note sys.warnoptions:
          3b3. in the reverse order: the last *note
          PyConfig.warnoptions: 3a3. item becomes the first item of
          ‘warnings.filters’ which is checked first (highest priority).

          The *note -W: 8d0. command line options adds its value to
          *note warnoptions: 3a3, it can be used multiple times.

          The *note PYTHONWARNINGS: bc8. environment variable can also
          be used to add warning options.  Multiple options can be
          specified, separated by commas (‘,’).

          Default: empty list.

      -- C Member: int write_bytecode

          If equal to ‘0’, Python won’t try to write ‘.pyc’ files on the
          import of source modules.

          Set to ‘0’ by the *note -B: 141b. command line option and the
          *note PYTHONDONTWRITEBYTECODE: 141c. environment variable.

          *note sys.dont_write_bytecode: 45b7. is initialized to the
          inverted value of *note write_bytecode: 3de.

          Default: ‘1’.

      -- C Member: *note PyWideStringList: 9b9. xoptions

          Values of the *note -X: 176. command line options: *note
          sys._xoptions: 1ee7.

          Default: empty list.

If *note parse_argv: 1a98. is non-zero, *note argv: 3c6. arguments are
parsed the same way the regular Python parses *note command line
arguments: 1042, and Python arguments are stripped from ‘argv’.

The *note xoptions: 3a4. options are parsed to set other options: see
the *note -X: 176. command line option.

Changed in version 3.9: The ‘show_alloc_count’ field has been removed.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0552/

   (2) https://peps.python.org/pep-0528/


File: python.info,  Node: Initialization with PyConfig,  Next: Isolated Configuration,  Prev: PyConfig,  Up: Python Initialization Configuration

7.10.7 Initialization with PyConfig
-----------------------------------

Initializing the interpreter from a populated configuration struct is
handled by calling *note Py_InitializeFromConfig(): 3c8.

The caller is responsible to handle exceptions (error or exit) using
*note PyStatus_Exception(): 9c4. and *note Py_ExitStatusException():
9cd.

If *note PyImport_FrozenModules(): 3018, *note PyImport_AppendInittab():
18bf. or *note PyImport_ExtendInittab(): 18c0. are used, they must be
set or called after Python preinitialization and before the Python
initialization.  If Python is initialized multiple times,
‘PyImport_AppendInittab()’ or ‘PyImport_ExtendInittab()’ must be called
before each Python initialization.

The current configuration (‘PyConfig’ type) is stored in
‘PyInterpreterState.config’.

Example setting the program name:

     void init_python(void)
     {
         PyStatus status;

         PyConfig config;
         PyConfig_InitPythonConfig(&config);

         /* Set the program name. Implicitly preinitialize Python. */
         status = PyConfig_SetString(&config, &config.program_name,
                                     L"/path/to/my_program");
         if (PyStatus_Exception(status)) {
             goto exception;
         }

         status = Py_InitializeFromConfig(&config);
         if (PyStatus_Exception(status)) {
             goto exception;
         }
         PyConfig_Clear(&config);
         return;

     exception:
         PyConfig_Clear(&config);
         Py_ExitStatusException(status);
     }

More complete example modifying the default configuration, read the
configuration, and then override some parameters.  Note that since 3.11,
many parameters are not calculated until initialization, and so values
cannot be read from the configuration structure.  Any values set before
initialize is called will be left unchanged by initialization:

     PyStatus init_python(const char *program_name)
     {
         PyStatus status;

         PyConfig config;
         PyConfig_InitPythonConfig(&config);

         /* Set the program name before reading the configuration
            (decode byte string from the locale encoding).

            Implicitly preinitialize Python. */
         status = PyConfig_SetBytesString(&config, &config.program_name,
                                          program_name);
         if (PyStatus_Exception(status)) {
             goto done;
         }

         /* Read all configuration at once */
         status = PyConfig_Read(&config);
         if (PyStatus_Exception(status)) {
             goto done;
         }

         /* Specify sys.path explicitly */
         /* If you want to modify the default set of paths, finish
            initialization first and then use PySys_GetObject("path") */
         config.module_search_paths_set = 1;
         status = PyWideStringList_Append(&config.module_search_paths,
                                          L"/path/to/stdlib");
         if (PyStatus_Exception(status)) {
             goto done;
         }
         status = PyWideStringList_Append(&config.module_search_paths,
                                          L"/path/to/more/modules");
         if (PyStatus_Exception(status)) {
             goto done;
         }

         /* Override executable computed by PyConfig_Read() */
         status = PyConfig_SetString(&config, &config.executable,
                                     L"/path/to/my_executable");
         if (PyStatus_Exception(status)) {
             goto done;
         }

         status = Py_InitializeFromConfig(&config);

     done:
         PyConfig_Clear(&config);
         return status;
     }


File: python.info,  Node: Isolated Configuration,  Next: Python Configuration,  Prev: Initialization with PyConfig,  Up: Python Initialization Configuration

7.10.8 Isolated Configuration
-----------------------------

*note PyPreConfig_InitIsolatedConfig(): 9c1. and *note
PyConfig_InitIsolatedConfig(): 9bb. functions create a configuration to
isolate Python from the system.  For example, to embed Python into an
application.

This configuration ignores global configuration variables, environment
variables, command line arguments (*note PyConfig.argv: 3c6. is not
parsed) and user site directory.  The C standard streams (ex: ‘stdout’)
and the LC_CTYPE locale are left unchanged.  Signal handlers are not
installed.

Configuration files are still used with this configuration to determine
paths that are unspecified.  Ensure *note PyConfig.home: 3be. is
specified to avoid computing the default path configuration.


File: python.info,  Node: Python Configuration,  Next: Python Path Configuration,  Prev: Isolated Configuration,  Up: Python Initialization Configuration

7.10.9 Python Configuration
---------------------------

*note PyPreConfig_InitPythonConfig(): 9c2. and *note
PyConfig_InitPythonConfig(): 9bc. functions create a configuration to
build a customized Python which behaves as the regular Python.

Environments variables and command line arguments are used to configure
Python, whereas global configuration variables are ignored.

This function enables C locale coercion ( PEP 538(1)) and *note Python
UTF-8 Mode: 659. ( PEP 540(2)) depending on the LC_CTYPE locale, *note
PYTHONUTF8: aee. and *note PYTHONCOERCECLOCALE: aeb. environment
variables.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0538/

   (2) https://peps.python.org/pep-0540/


File: python.info,  Node: Python Path Configuration,  Next: Py_GetArgcArgv,  Prev: Python Configuration,  Up: Python Initialization Configuration

7.10.10 Python Path Configuration
---------------------------------

*note PyConfig: 3a9. contains multiple fields for the path
configuration:

   * Path configuration inputs:

        * *note PyConfig.home: 3be.

        * *note PyConfig.platlibdir: 1ac8.

        * *note PyConfig.pathconfig_warnings: 3da.

        * *note PyConfig.program_name: 3c7.

        * *note PyConfig.pythonpath_env: 5227.

        * current working directory: to get absolute paths

        * ‘PATH’ environment variable to get the program full path (from
          *note PyConfig.program_name: 3c7.)

        * ‘__PYVENV_LAUNCHER__’ environment variable

        * (Windows only) Application paths in the registry under
          “SoftwarePythonPythonCoreX.YPythonPath” of HKEY_CURRENT_USER
          and HKEY_LOCAL_MACHINE (where X.Y is the Python version).

   * Path configuration output fields:

        * *note PyConfig.base_exec_prefix: 5218.

        * *note PyConfig.base_executable: 521a.

        * *note PyConfig.base_prefix: 521b.

        * *note PyConfig.exec_prefix: 5219.

        * *note PyConfig.executable: 3a8.

        * *note PyConfig.module_search_paths_set: 5f2, *note
          PyConfig.module_search_paths: 3a5.

        * *note PyConfig.prefix: 521c.

If at least one “output field” is not set, Python calculates the path
configuration to fill unset fields.  If *note module_search_paths_set:
5f2. is equal to ‘0’, *note module_search_paths: 3a5. is overridden and
‘module_search_paths_set’ is set to ‘1’.

It is possible to completely ignore the function calculating the default
path configuration by setting explicitly all path configuration output
fields listed above.  A string is considered as set even if it is
non-empty.  ‘module_search_paths’ is considered as set if
‘module_search_paths_set’ is set to ‘1’.  In this case,
‘module_search_paths’ will be used without modification.

Set *note pathconfig_warnings: 3da. to ‘0’ to suppress warnings when
calculating the path configuration (Unix only, Windows does not log any
warning).

If *note base_prefix: 521b. or *note base_exec_prefix: 5218. fields are
not set, they inherit their value from *note prefix: 521c. and *note
exec_prefix: 5219. respectively.

*note Py_RunMain(): 9d0. and *note Py_Main(): c45. modify *note
sys.path: 3b7.:

   * If *note run_filename: 51b6. is set and is a directory which
     contains a ‘__main__.py’ script, prepend ‘run_filename’ to *note
     sys.path: 3b7.

   * If *note isolated: 3e7. is zero:

        * If *note run_module: 51b7. is set, prepend the current
          directory to *note sys.path: 3b7.  Do nothing if the current
          directory cannot be read.

        * If *note run_filename: 51b6. is set, prepend the directory of
          the filename to *note sys.path: 3b7.

        * Otherwise, prepend an empty string to *note sys.path: 3b7.

If *note site_import: 3d6. is non-zero, *note sys.path: 3b7. can be
modified by the *note site: c7. module.  If *note user_site_directory:
3e0. is non-zero and the user’s site-package directory exists, the
‘site’ module appends the user’s site-package directory to ‘sys.path’.

The following configuration files are used by the path configuration:

   * ‘pyvenv.cfg’

   * ‘._pth’ file (ex: ‘python._pth’)

   * ‘pybuilddir.txt’ (Unix only)

If a ‘._pth’ file is present:

   * Set *note isolated: 3e7. to ‘1’.

   * Set *note use_environment: 3dc. to ‘0’.

   * Set *note site_import: 3d6. to ‘0’.

   * Set *note safe_path: 776. to ‘1’.

The ‘__PYVENV_LAUNCHER__’ environment variable is used to set *note
PyConfig.base_executable: 521a.


File: python.info,  Node: Py_GetArgcArgv,  Next: Multi-Phase Initialization Private Provisional API,  Prev: Python Path Configuration,  Up: Python Initialization Configuration

7.10.11 Py_GetArgcArgv()
------------------------

 -- C Function: void Py_GetArgcArgv (int *argc, wchar_t ***argv)

     Get the original command line arguments, before Python modified
     them.

     See also *note PyConfig.orig_argv: 89b. member.


File: python.info,  Node: Multi-Phase Initialization Private Provisional API,  Prev: Py_GetArgcArgv,  Up: Python Initialization Configuration

7.10.12 Multi-Phase Initialization Private Provisional API
----------------------------------------------------------

This section is a private provisional API introducing multi-phase
initialization, the core feature of PEP 432(1):

   * “Core” initialization phase, “bare minimum Python”:

        * Builtin types;

        * Builtin exceptions;

        * Builtin and frozen modules;

        * The *note sys: d9. module is only partially initialized (ex:
          *note sys.path: 3b7. doesn’t exist yet).

   * “Main” initialization phase, Python is fully initialized:

        * Install and configure *note importlib: 77.;

        * Apply the *note Path Configuration: 8b5.;

        * Install signal handlers;

        * Finish *note sys: d9. module initialization (ex: create *note
          sys.stdout: aec. and *note sys.path: 3b7.);

        * Enable optional features like *note faulthandler: 58. and
          *note tracemalloc: ff.;

        * Import the *note site: c7. module;

        * etc.

Private provisional API:

   * ‘PyConfig._init_main’: if set to ‘0’, *note
     Py_InitializeFromConfig(): 3c8. stops at the “Core” initialization
     phase.

 -- C Function: *note PyStatus: 9b8. _Py_InitializeMain (void)

     Move to the “Main” initialization phase, finish the Python
     initialization.

No module is imported during the “Core” phase and the ‘importlib’ module
is not configured: the *note Path Configuration: 8b5. is only applied
during the “Main” phase.  It may allow to customize Python in Python to
override or tune the *note Path Configuration: 8b5, maybe install a
custom *note sys.meta_path: d53. importer or an import hook, etc.

It may become possible to calculate the *note Path Configuration: 8b5.
in Python, after the Core phase and before the Main phase, which is one
of the PEP 432(2) motivation.

The “Core” phase is not properly defined: what should be and what should
not be available at this phase is not specified yet.  The API is marked
as private and provisional: the API can be modified or even be removed
anytime until a proper public API is designed.

Example running Python code between “Core” and “Main” initialization
phases:

     void init_python(void)
     {
         PyStatus status;

         PyConfig config;
         PyConfig_InitPythonConfig(&config);
         config._init_main = 0;

         /* ... customize 'config' configuration ... */

         status = Py_InitializeFromConfig(&config);
         PyConfig_Clear(&config);
         if (PyStatus_Exception(status)) {
             Py_ExitStatusException(status);
         }

         /* Use sys.stderr because sys.stdout is only created
            by _Py_InitializeMain() */
         int res = PyRun_SimpleString(
             "import sys; "
             "print('Run Python code before _Py_InitializeMain', "
                    "file=sys.stderr)");
         if (res < 0) {
             exit(1);
         }

         /* ... put more configuration code here ... */

         status = _Py_InitializeMain();
         if (PyStatus_Exception(status)) {
             Py_ExitStatusException(status);
         }
     }

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0432/

   (2) https://peps.python.org/pep-0432/


File: python.info,  Node: Memory Management,  Next: Object Implementation Support,  Prev: Python Initialization Configuration,  Up: Python/C API Reference Manual

7.11 Memory Management
======================

* Menu:

* Overview: Overview<4>.
* Allocator Domains::
* Raw Memory Interface::
* Memory Interface::
* Object allocators::
* Default Memory Allocators::
* Customize Memory Allocators::
* Debug hooks on the Python memory allocators::
* The pymalloc allocator::
* The mimalloc allocator::
* tracemalloc C API::
* Examples: Examples<37>.


File: python.info,  Node: Overview<4>,  Next: Allocator Domains,  Up: Memory Management

7.11.1 Overview
---------------

Memory management in Python involves a private heap containing all
Python objects and data structures.  The management of this private heap
is ensured internally by the 'Python memory manager'.  The Python memory
manager has different components which deal with various dynamic storage
management aspects, like sharing, segmentation, preallocation or
caching.

At the lowest level, a raw memory allocator ensures that there is enough
room in the private heap for storing all Python-related data by
interacting with the memory manager of the operating system.  On top of
the raw memory allocator, several object-specific allocators operate on
the same heap and implement distinct memory management policies adapted
to the peculiarities of every object type.  For example, integer objects
are managed differently within the heap than strings, tuples or
dictionaries because integers imply different storage requirements and
speed/space tradeoffs.  The Python memory manager thus delegates some of
the work to the object-specific allocators, but ensures that the latter
operate within the bounds of the private heap.

It is important to understand that the management of the Python heap is
performed by the interpreter itself and that the user has no control
over it, even if they regularly manipulate object pointers to memory
blocks inside that heap.  The allocation of heap space for Python
objects and other internal buffers is performed on demand by the Python
memory manager through the Python/C API functions listed in this
document.

To avoid memory corruption, extension writers should never try to
operate on Python objects with the functions exported by the C library:
‘malloc()’, ‘calloc()’, ‘realloc()’ and ‘free()’.  This will result in
mixed calls between the C allocator and the Python memory manager with
fatal consequences, because they implement different algorithms and
operate on different heaps.  However, one may safely allocate and
release memory blocks with the C library allocator for individual
purposes, as shown in the following example:

     PyObject *res;
     char *buf = (char *) malloc(BUFSIZ); /* for I/O */

     if (buf == NULL)
         return PyErr_NoMemory();
     ...Do some I/O operation involving buf...
     res = PyBytes_FromString(buf);
     free(buf); /* malloc'ed */
     return res;

In this example, the memory request for the I/O buffer is handled by the
C library allocator.  The Python memory manager is involved only in the
allocation of the bytes object returned as a result.

In most situations, however, it is recommended to allocate memory from
the Python heap specifically because the latter is under control of the
Python memory manager.  For example, this is required when the
interpreter is extended with new object types written in C. Another
reason for using the Python heap is the desire to 'inform' the Python
memory manager about the memory needs of the extension module.  Even
when the requested memory is used exclusively for internal, highly
specific purposes, delegating all memory requests to the Python memory
manager causes the interpreter to have a more accurate image of its
memory footprint as a whole.  Consequently, under certain circumstances,
the Python memory manager may or may not trigger appropriate actions,
like garbage collection, memory compaction or other preventive
procedures.  Note that by using the C library allocator as shown in the
previous example, the allocated memory for the I/O buffer escapes
completely the Python memory manager.

See also
........

The *note PYTHONMALLOC: c85. environment variable can be used to
configure the memory allocators used by Python.

The *note PYTHONMALLOCSTATS: 1ce8. environment variable can be used to
print statistics of the *note pymalloc memory allocator: d37. every time
a new pymalloc object arena is created, and on shutdown.


File: python.info,  Node: Allocator Domains,  Next: Raw Memory Interface,  Prev: Overview<4>,  Up: Memory Management

7.11.2 Allocator Domains
------------------------

All allocating functions belong to one of three different “domains” (see
also *note PyMemAllocatorDomain: 523c.).  These domains represent
different allocation strategies and are optimized for different
purposes.  The specific details on how every domain allocates memory or
what internal functions each domain calls is considered an
implementation detail, but for debugging purposes a simplified table can
be found at *note Default Memory Allocators: 1ef3.  The APIs used to
allocate and free a block of memory must be from the same domain.  For
example, *note PyMem_Free(): 1491. must be used to free memory allocated
using *note PyMem_Malloc(): c87.

The three allocation domains are:

   * Raw domain: intended for allocating memory for general-purpose
     memory buffers where the allocation 'must' go to the system
     allocator or where the allocator can operate without the *note GIL:
     159.  The memory is requested directly from the system.  See *note
     Raw Memory Interface: 523d.

   * “Mem” domain: intended for allocating memory for Python buffers and
     general-purpose memory buffers where the allocation must be
     performed with the *note GIL: 159. held.  The memory is taken from
     the Python private heap.  See *note Memory Interface: 523e.

   * Object domain: intended for allocating memory for Python objects.
     The memory is taken from the Python private heap.  See *note Object
     allocators: 523f.

     Note: The *note free-threaded: 15b3. build requires that only
     Python objects are allocated using the “object” domain and that all
     Python objects are allocated using that domain.  This differs from
     the prior Python versions, where this was only a best practice and
     not a hard requirement.

     For example, buffers (non-Python objects) should be allocated using
     *note PyMem_Malloc(): c87, *note PyMem_RawMalloc(): 393, or
     ‘malloc()’, but not *note PyObject_Malloc(): c89.

     See *note Memory Allocation APIs: 5240.


File: python.info,  Node: Raw Memory Interface,  Next: Memory Interface,  Prev: Allocator Domains,  Up: Memory Management

7.11.3 Raw Memory Interface
---------------------------

The following function sets are wrappers to the system allocator.  These
functions are thread-safe, the *note GIL: 148. does not need to be held.

The *note default raw memory allocator: 1ef3. uses the following
functions: ‘malloc()’, ‘calloc()’, ‘realloc()’ and ‘free()’; call
‘malloc(1)’ (or ‘calloc(1, 1)’) when requesting zero bytes.

Added in version 3.4.

 -- C Function: void *PyMem_RawMalloc (size_t n)
     ' Part of the *note Stable ABI: 556. since version 3.13.'
     Allocates 'n' bytes and returns a pointer of type void* to the
     allocated memory, or ‘NULL’ if the request fails.

     Requesting zero bytes returns a distinct non-‘NULL’ pointer if
     possible, as if ‘PyMem_RawMalloc(1)’ had been called instead.  The
     memory will not have been initialized in any way.

 -- C Function: void *PyMem_RawCalloc (size_t nelem, size_t elsize)
     ' Part of the *note Stable ABI: 556. since version 3.13.'
     Allocates 'nelem' elements each whose size in bytes is 'elsize' and
     returns a pointer of type void* to the allocated memory, or ‘NULL’
     if the request fails.  The memory is initialized to zeros.

     Requesting zero elements or elements of size zero bytes returns a
     distinct non-‘NULL’ pointer if possible, as if ‘PyMem_RawCalloc(1,
     1)’ had been called instead.

     Added in version 3.5.

 -- C Function: void *PyMem_RawRealloc (void *p, size_t n)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Resizes
     the memory block pointed to by 'p' to 'n' bytes.  The contents will
     be unchanged to the minimum of the old and the new sizes.

     If 'p' is ‘NULL’, the call is equivalent to ‘PyMem_RawMalloc(n)’;
     else if 'n' is equal to zero, the memory block is resized but is
     not freed, and the returned pointer is non-‘NULL’.

     Unless 'p' is ‘NULL’, it must have been returned by a previous call
     to *note PyMem_RawMalloc(): 393, *note PyMem_RawRealloc(): 395. or
     *note PyMem_RawCalloc(): 394.

     If the request fails, *note PyMem_RawRealloc(): 395. returns ‘NULL’
     and 'p' remains a valid pointer to the previous memory area.

 -- C Function: void PyMem_RawFree (void *p)
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Frees
     the memory block pointed to by 'p', which must have been returned
     by a previous call to *note PyMem_RawMalloc(): 393, *note
     PyMem_RawRealloc(): 395. or *note PyMem_RawCalloc(): 394.
     Otherwise, or if ‘PyMem_RawFree(p)’ has been called before,
     undefined behavior occurs.

     If 'p' is ‘NULL’, no operation is performed.


File: python.info,  Node: Memory Interface,  Next: Object allocators,  Prev: Raw Memory Interface,  Up: Memory Management

7.11.4 Memory Interface
-----------------------

The following function sets, modeled after the ANSI C standard, but
specifying behavior when requesting zero bytes, are available for
allocating and releasing memory from the Python heap.

The *note default memory allocator: 1ef3. uses the *note pymalloc memory
allocator: d37.

     Warning: The *note GIL: 148. must be held when using these
     functions.

Changed in version 3.6: The default allocator is now pymalloc instead of
system ‘malloc()’.

 -- C Function: void *PyMem_Malloc (size_t n)
     ' Part of the *note Stable ABI: 556.'  Allocates 'n' bytes and
     returns a pointer of type void* to the allocated memory, or ‘NULL’
     if the request fails.

     Requesting zero bytes returns a distinct non-‘NULL’ pointer if
     possible, as if ‘PyMem_Malloc(1)’ had been called instead.  The
     memory will not have been initialized in any way.

 -- C Function: void *PyMem_Calloc (size_t nelem, size_t elsize)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Allocates
     'nelem' elements each whose size in bytes is 'elsize' and returns a
     pointer of type void* to the allocated memory, or ‘NULL’ if the
     request fails.  The memory is initialized to zeros.

     Requesting zero elements or elements of size zero bytes returns a
     distinct non-‘NULL’ pointer if possible, as if ‘PyMem_Calloc(1, 1)’
     had been called instead.

     Added in version 3.5.

 -- C Function: void *PyMem_Realloc (void *p, size_t n)
     ' Part of the *note Stable ABI: 556.'  Resizes the memory block
     pointed to by 'p' to 'n' bytes.  The contents will be unchanged to
     the minimum of the old and the new sizes.

     If 'p' is ‘NULL’, the call is equivalent to ‘PyMem_Malloc(n)’; else
     if 'n' is equal to zero, the memory block is resized but is not
     freed, and the returned pointer is non-‘NULL’.

     Unless 'p' is ‘NULL’, it must have been returned by a previous call
     to *note PyMem_Malloc(): c87, *note PyMem_Realloc(): 106f. or *note
     PyMem_Calloc(): ee1.

     If the request fails, *note PyMem_Realloc(): 106f. returns ‘NULL’
     and 'p' remains a valid pointer to the previous memory area.

 -- C Function: void PyMem_Free (void *p)
     ' Part of the *note Stable ABI: 556.'  Frees the memory block
     pointed to by 'p', which must have been returned by a previous call
     to *note PyMem_Malloc(): c87, *note PyMem_Realloc(): 106f. or *note
     PyMem_Calloc(): ee1.  Otherwise, or if ‘PyMem_Free(p)’ has been
     called before, undefined behavior occurs.

     If 'p' is ‘NULL’, no operation is performed.

The following type-oriented macros are provided for convenience.  Note
that 'TYPE' refers to any C type.

 -- C Macro: PyMem_New (TYPE, n)

     Same as *note PyMem_Malloc(): c87, but allocates ‘(n *
     sizeof(TYPE))’ bytes of memory.  Returns a pointer cast to ‘TYPE*’.
     The memory will not have been initialized in any way.

 -- C Macro: PyMem_Resize (p, TYPE, n)

     Same as *note PyMem_Realloc(): 106f, but the memory block is
     resized to ‘(n * sizeof(TYPE))’ bytes.  Returns a pointer cast to
     ‘TYPE*’.  On return, 'p' will be a pointer to the new memory area,
     or ‘NULL’ in the event of failure.

     This is a C preprocessor macro; 'p' is always reassigned.  Save the
     original value of 'p' to avoid losing memory when handling errors.

 -- C Function: void PyMem_Del (void *p)

     Same as *note PyMem_Free(): 1491.

* Menu:

* Deprecated aliases: Deprecated aliases<2>.


File: python.info,  Node: Deprecated aliases<2>,  Up: Memory Interface

7.11.4.1 Deprecated aliases
...........................

These are *note soft deprecated: 209. aliases to existing functions and
macros.  They exist solely for backwards compatibility.

Deprecated alias                                       Corresponding function or macro
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Macro: PyMem_MALLOC (size)                       *note PyMem_Malloc(): c87.
                                                       
                                                       
 -- C Macro: PyMem_NEW (type, size)                    *note PyMem_New: 1574.
                                                       
                                                       
 -- C Macro: PyMem_REALLOC (ptr, size)                 *note PyMem_Realloc(): 106f.
                                                       
                                                       
 -- C Macro: PyMem_RESIZE (ptr, type, size)            *note PyMem_Resize: 5243.
                                                       
                                                       
 -- C Macro: PyMem_FREE (ptr)                          *note PyMem_Free(): 1491.
                                                       
                                                       
 -- C Macro: PyMem_DEL (ptr)                           *note PyMem_Free(): 1491.
                                                       

Changed in version 3.4: The macros are now aliases of the corresponding
functions and macros.  Previously, their behavior was the same, but
their use did not necessarily preserve binary compatibility across
Python versions.

Deprecated since version 2.0.


File: python.info,  Node: Object allocators,  Next: Default Memory Allocators,  Prev: Memory Interface,  Up: Memory Management

7.11.5 Object allocators
------------------------

The following function sets, modeled after the ANSI C standard, but
specifying behavior when requesting zero bytes, are available for
allocating and releasing memory from the Python heap.

     Note: There is no guarantee that the memory returned by these
     allocators can be successfully cast to a Python object when
     intercepting the allocating functions in this domain by the methods
     described in the *note Customize Memory Allocators: 524c. section.

The *note default object allocator: 1ef3. uses the *note pymalloc memory
allocator: d37.

     Warning: The *note GIL: 148. must be held when using these
     functions.

 -- C Function: void *PyObject_Malloc (size_t n)
     ' Part of the *note Stable ABI: 556.'  Allocates 'n' bytes and
     returns a pointer of type void* to the allocated memory, or ‘NULL’
     if the request fails.

     Requesting zero bytes returns a distinct non-‘NULL’ pointer if
     possible, as if ‘PyObject_Malloc(1)’ had been called instead.  The
     memory will not have been initialized in any way.

 -- C Function: void *PyObject_Calloc (size_t nelem, size_t elsize)
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Allocates
     'nelem' elements each whose size in bytes is 'elsize' and returns a
     pointer of type void* to the allocated memory, or ‘NULL’ if the
     request fails.  The memory is initialized to zeros.

     Requesting zero elements or elements of size zero bytes returns a
     distinct non-‘NULL’ pointer if possible, as if ‘PyObject_Calloc(1,
     1)’ had been called instead.

     Added in version 3.5.

 -- C Function: void *PyObject_Realloc (void *p, size_t n)
     ' Part of the *note Stable ABI: 556.'  Resizes the memory block
     pointed to by 'p' to 'n' bytes.  The contents will be unchanged to
     the minimum of the old and the new sizes.

     If 'p' is ‘NULL’, the call is equivalent to ‘PyObject_Malloc(n)’;
     else if 'n' is equal to zero, the memory block is resized but is
     not freed, and the returned pointer is non-‘NULL’.

     Unless 'p' is ‘NULL’, it must have been returned by a previous call
     to *note PyObject_Malloc(): c89, *note PyObject_Realloc(): 1492. or
     *note PyObject_Calloc(): ee2.

     If the request fails, *note PyObject_Realloc(): 1492. returns
     ‘NULL’ and 'p' remains a valid pointer to the previous memory area.

 -- C Function: void PyObject_Free (void *p)
     ' Part of the *note Stable ABI: 556.'  Frees the memory block
     pointed to by 'p', which must have been returned by a previous call
     to *note PyObject_Malloc(): c89, *note PyObject_Realloc(): 1492. or
     *note PyObject_Calloc(): ee2.  Otherwise, or if ‘PyObject_Free(p)’
     has been called before, undefined behavior occurs.

     If 'p' is ‘NULL’, no operation is performed.


File: python.info,  Node: Default Memory Allocators,  Next: Customize Memory Allocators,  Prev: Object allocators,  Up: Memory Management

7.11.6 Default Memory Allocators
--------------------------------

Default memory allocators:

Configuration                       Name                     PyMem_RawMalloc        PyMem_Malloc              PyObject_Malloc
                                                                                                              
---------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              
Release build                       ‘"pymalloc"’             ‘malloc’               ‘pymalloc’                ‘pymalloc’
                                                                                                              
                                                                                                              
Debug build                         ‘"pymalloc_debug"’       ‘malloc’ + debug       ‘pymalloc’ + debug        ‘pymalloc’ + debug
                                                                                                              
                                                                                                              
Release build, without pymalloc     ‘"malloc"’               ‘malloc’               ‘malloc’                  ‘malloc’
                                                                                                              
                                                                                                              
Debug build, without pymalloc       ‘"malloc_debug"’         ‘malloc’ + debug       ‘malloc’ + debug          ‘malloc’ + debug
                                                                                                              

Legend:

   * Name: value for *note PYTHONMALLOC: c85. environment variable.

   * ‘malloc’: system allocators from the standard C library, C
     functions: ‘malloc()’, ‘calloc()’, ‘realloc()’ and ‘free()’.

   * ‘pymalloc’: *note pymalloc memory allocator: d37.

   * ‘mimalloc’: *note mimalloc memory allocator: 1ef5.  The pymalloc
     allocator will be used if mimalloc support isn’t available.

   * “+ debug”: with *note debug hooks on the Python memory allocators:
     1ef6.

   * “Debug build”: *note Python build in debug mode: 1f9.


File: python.info,  Node: Customize Memory Allocators,  Next: Debug hooks on the Python memory allocators,  Prev: Default Memory Allocators,  Up: Memory Management

7.11.7 Customize Memory Allocators
----------------------------------

Added in version 3.4.

 -- C Type: type PyMemAllocatorEx

     Structure used to describe a memory block allocator.  The structure
     has the following fields:

     Field                                                          Meaning
                                                                    
     -----------------------------------------------------------------------------------------------------------
                                                                    
     ‘void *ctx’                                                    user context passed as first argument
                                                                    
                                                                    
     ‘void* malloc(void *ctx, size_t size)’                         allocate a memory block
                                                                    
                                                                    
     ‘void* calloc(void *ctx, size_t nelem, size_t elsize)’         allocate a memory block initialized with
                                                                    zeros
                                                                    
                                                                    
     ‘void* realloc(void *ctx, void *ptr, size_t new_size)’         allocate or resize a memory block
                                                                    
                                                                    
     ‘void free(void *ctx, void *ptr)’                              free a memory block
                                                                    

     Changed in version 3.5: The ‘PyMemAllocator’ structure was renamed
     to *note PyMemAllocatorEx: f02. and a new ‘calloc’ field was added.

 -- C Type: type PyMemAllocatorDomain

     Enum used to identify an allocator domain.  Domains:

      -- C Macro: PYMEM_DOMAIN_RAW

          Functions:

             * *note PyMem_RawMalloc(): 393.

             * *note PyMem_RawRealloc(): 395.

             * *note PyMem_RawCalloc(): 394.

             * *note PyMem_RawFree(): 396.

      -- C Macro: PYMEM_DOMAIN_MEM

          Functions:

             * *note PyMem_Malloc(): c87,

             * *note PyMem_Realloc(): 106f.

             * *note PyMem_Calloc(): ee1.

             * *note PyMem_Free(): 1491.

      -- C Macro: PYMEM_DOMAIN_OBJ

          Functions:

             * *note PyObject_Malloc(): c89.

             * *note PyObject_Realloc(): 1492.

             * *note PyObject_Calloc(): ee2.

             * *note PyObject_Free(): c86.

 -- C Function: void PyMem_GetAllocator (PyMemAllocatorDomain domain,
          PyMemAllocatorEx *allocator)

     Get the memory block allocator of the specified domain.

 -- C Function: void PyMem_SetAllocator (PyMemAllocatorDomain domain,
          PyMemAllocatorEx *allocator)

     Set the memory block allocator of the specified domain.

     The new allocator must return a distinct non-‘NULL’ pointer when
     requesting zero bytes.

     For the *note PYMEM_DOMAIN_RAW: 1ef4. domain, the allocator must be
     thread-safe: the *note GIL: 148. is not held when the allocator is
     called.

     For the remaining domains, the allocator must also be thread-safe:
     the allocator may be called in different interpreters that do not
     share a ‘GIL’.

     If the new allocator is not a hook (does not call the previous
     allocator), the *note PyMem_SetupDebugHooks(): c8b. function must
     be called to reinstall the debug hooks on top on the new allocator.

     See also *note PyPreConfig.allocator: 520c. and *note Preinitialize
     Python with PyPreConfig: 3fa2.

          Warning: *note PyMem_SetAllocator(): 58e. does have the
          following contract:

             * It can be called after *note Py_PreInitialize(): 3ee. and
               before *note Py_InitializeFromConfig(): 3c8. to install a
               custom memory allocator.  There are no restrictions over
               the installed allocator other than the ones imposed by
               the domain (for instance, the Raw Domain allows the
               allocator to be called without the GIL held).  See *note
               the section on allocator domains: 523b. for more
               information.

             * If called after Python has finish initializing (after
               *note Py_InitializeFromConfig(): 3c8. has been called)
               the allocator 'must' wrap the existing allocator.
               Substituting the current allocator for some other
               arbitrary one is 'not supported'.

     Changed in version 3.12: All allocators must be thread-safe.

 -- C Function: void PyMem_SetupDebugHooks (void)

     Setup *note debug hooks in the Python memory allocators: 1ef6. to
     detect memory errors.


File: python.info,  Node: Debug hooks on the Python memory allocators,  Next: The pymalloc allocator,  Prev: Customize Memory Allocators,  Up: Memory Management

7.11.8 Debug hooks on the Python memory allocators
--------------------------------------------------

When *note Python is built in debug mode: 1f9, the *note
PyMem_SetupDebugHooks(): c8b. function is called at the *note Python
preinitialization: 3fa2. to setup debug hooks on Python memory
allocators to detect memory errors.

The *note PYTHONMALLOC: c85. environment variable can be used to install
debug hooks on a Python compiled in release mode (ex:
‘PYTHONMALLOC=debug’).

The *note PyMem_SetupDebugHooks(): c8b. function can be used to set
debug hooks after calling *note PyMem_SetAllocator(): 58e.

These debug hooks fill dynamically allocated memory blocks with special,
recognizable bit patterns.  Newly allocated memory is filled with the
byte ‘0xCD’ (‘PYMEM_CLEANBYTE’), freed memory is filled with the byte
‘0xDD’ (‘PYMEM_DEADBYTE’).  Memory blocks are surrounded by “forbidden
bytes” filled with the byte ‘0xFD’ (‘PYMEM_FORBIDDENBYTE’).  Strings of
these bytes are unlikely to be valid addresses, floats, or ASCII
strings.

Runtime checks:

   - Detect API violations.  For example, detect if *note
     PyObject_Free(): c86. is called on a memory block allocated by
     *note PyMem_Malloc(): c87.

   - Detect write before the start of the buffer (buffer underflow).

   - Detect write after the end of the buffer (buffer overflow).

   - Check that the *note GIL: 148. is held when allocator functions of
     *note PYMEM_DOMAIN_OBJ: c88. (ex: *note PyObject_Malloc(): c89.)
     and *note PYMEM_DOMAIN_MEM: c8a. (ex: *note PyMem_Malloc(): c87.)
     domains are called.

On error, the debug hooks use the *note tracemalloc: ff. module to get
the traceback where a memory block was allocated.  The traceback is only
displayed if ‘tracemalloc’ is tracing Python memory allocations and the
memory block was traced.

Let 'S' = ‘sizeof(size_t)’.  ‘2*S’ bytes are added at each end of each
block of 'N' bytes requested.  The memory layout is like so, where p
represents the address returned by a malloc-like or realloc-like
function (‘p[i:j]’ means the slice of bytes from ‘*(p+i)’ inclusive up
to ‘*(p+j)’ exclusive; note that the treatment of negative indices
differs from a Python slice):

‘p[-2*S:-S]’

     Number of bytes originally asked for.  This is a size_t, big-endian
     (easier to read in a memory dump).

‘p[-S]’

     API identifier (ASCII character):

        * ‘'r'’ for *note PYMEM_DOMAIN_RAW: 1ef4.

        * ‘'m'’ for *note PYMEM_DOMAIN_MEM: c8a.

        * ‘'o'’ for *note PYMEM_DOMAIN_OBJ: c88.

‘p[-S+1:0]’

     Copies of PYMEM_FORBIDDENBYTE. Used to catch under- writes and
     reads.

‘p[0:N]’

     The requested memory, filled with copies of PYMEM_CLEANBYTE, used
     to catch reference to uninitialized memory.  When a realloc-like
     function is called requesting a larger memory block, the new excess
     bytes are also filled with PYMEM_CLEANBYTE. When a free-like
     function is called, these are overwritten with PYMEM_DEADBYTE, to
     catch reference to freed memory.  When a realloc- like function is
     called requesting a smaller memory block, the excess old bytes are
     also filled with PYMEM_DEADBYTE.

‘p[N:N+S]’

     Copies of PYMEM_FORBIDDENBYTE. Used to catch over- writes and
     reads.

‘p[N+S:N+2*S]’

     Only used if the ‘PYMEM_DEBUG_SERIALNO’ macro is defined (not
     defined by default).

     A serial number, incremented by 1 on each call to a malloc-like or
     realloc-like function.  Big-endian ‘size_t’.  If “bad memory” is
     detected later, the serial number gives an excellent way to set a
     breakpoint on the next run, to capture the instant at which this
     block was passed out.  The static function bumpserialno() in
     obmalloc.c is the only place the serial number is incremented, and
     exists so you can set such a breakpoint easily.

A realloc-like or free-like function first checks that the
PYMEM_FORBIDDENBYTE bytes at each end are intact.  If they’ve been
altered, diagnostic output is written to stderr, and the program is
aborted via Py_FatalError().  The other main failure mode is provoking a
memory error when a program reads up one of the special bit patterns and
tries to use it as an address.  If you get in a debugger then and look
at the object, you’re likely to see that it’s entirely filled with
PYMEM_DEADBYTE (meaning freed memory is getting used) or PYMEM_CLEANBYTE
(meaning uninitialized memory is getting used).

Changed in version 3.6: The *note PyMem_SetupDebugHooks(): c8b. function
now also works on Python compiled in release mode.  On error, the debug
hooks now use *note tracemalloc: ff. to get the traceback where a memory
block was allocated.  The debug hooks now also check if the GIL is held
when functions of *note PYMEM_DOMAIN_OBJ: c88. and *note
PYMEM_DOMAIN_MEM: c8a. domains are called.

Changed in version 3.8: Byte patterns ‘0xCB’ (‘PYMEM_CLEANBYTE’), ‘0xDB’
(‘PYMEM_DEADBYTE’) and ‘0xFB’ (‘PYMEM_FORBIDDENBYTE’) have been replaced
with ‘0xCD’, ‘0xDD’ and ‘0xFD’ to use the same values than Windows CRT
debug ‘malloc()’ and ‘free()’.


File: python.info,  Node: The pymalloc allocator,  Next: The mimalloc allocator,  Prev: Debug hooks on the Python memory allocators,  Up: Memory Management

7.11.9 The pymalloc allocator
-----------------------------

Python has a 'pymalloc' allocator optimized for small objects (smaller
or equal to 512 bytes) with a short lifetime.  It uses memory mappings
called “arenas” with a fixed size of either 256 KiB on 32-bit platforms
or 1 MiB on 64-bit platforms.  It falls back to *note PyMem_RawMalloc():
393. and *note PyMem_RawRealloc(): 395. for allocations larger than 512
bytes.

'pymalloc' is the *note default allocator: 1ef3. of the *note
PYMEM_DOMAIN_MEM: c8a. (ex: *note PyMem_Malloc(): c87.) and *note
PYMEM_DOMAIN_OBJ: c88. (ex: *note PyObject_Malloc(): c89.) domains.

The arena allocator uses the following functions:

   * ‘VirtualAlloc()’ and ‘VirtualFree()’ on Windows,

   * ‘mmap()’ and ‘munmap()’ if available,

   * ‘malloc()’ and ‘free()’ otherwise.

This allocator is disabled if Python is configured with the *note
-without-pymalloc: 1f55. option.  It can also be disabled at runtime
using the *note PYTHONMALLOC: c85. environment variable (ex:
‘PYTHONMALLOC=malloc’).

Typically, it makes sense to disable the pymalloc allocator when
building Python with AddressSanitizer (*note -with-address-sanitizer:
1f5d.) which helps uncover low level bugs within the C code.

* Menu:

* Customize pymalloc Arena Allocator::


File: python.info,  Node: Customize pymalloc Arena Allocator,  Up: The pymalloc allocator

7.11.9.1 Customize pymalloc Arena Allocator
...........................................

Added in version 3.4.

 -- C Type: type PyObjectArenaAllocator

     Structure used to describe an arena allocator.  The structure has
     three fields:

     Field                                                  Meaning
                                                            
     ---------------------------------------------------------------------------------------------------
                                                            
     ‘void *ctx’                                            user context passed as first argument
                                                            
                                                            
     ‘void* alloc(void *ctx, size_t size)’                  allocate an arena of size bytes
                                                            
                                                            
     ‘void free(void *ctx, void *ptr, size_t size)’         free an arena
                                                            

 -- C Function: void PyObject_GetArenaAllocator (PyObjectArenaAllocator
          *allocator)

     Get the arena allocator.

 -- C Function: void PyObject_SetArenaAllocator (PyObjectArenaAllocator
          *allocator)

     Set the arena allocator.


File: python.info,  Node: The mimalloc allocator,  Next: tracemalloc C API,  Prev: The pymalloc allocator,  Up: Memory Management

7.11.10 The mimalloc allocator
------------------------------

Added in version 3.13.

Python supports the mimalloc allocator when the underlying platform
support is available.  mimalloc “is a general purpose allocator with
excellent performance characteristics.  Initially developed by Daan
Leijen for the runtime systems of the Koka and Lean languages.”


File: python.info,  Node: tracemalloc C API,  Next: Examples<37>,  Prev: The mimalloc allocator,  Up: Memory Management

7.11.11 tracemalloc C API
-------------------------

Added in version 3.7.

 -- C Function: int PyTraceMalloc_Track (unsigned int domain, uintptr_t
          ptr, size_t size)

     Track an allocated memory block in the *note tracemalloc: ff.
     module.

     Return ‘0’ on success, return ‘-1’ on error (failed to allocate
     memory to store the trace).  Return ‘-2’ if tracemalloc is
     disabled.

     If memory block is already tracked, update the existing trace.

 -- C Function: int PyTraceMalloc_Untrack (unsigned int domain,
          uintptr_t ptr)

     Untrack an allocated memory block in the *note tracemalloc: ff.
     module.  Do nothing if the block was not tracked.

     Return ‘-2’ if tracemalloc is disabled, otherwise return ‘0’.


File: python.info,  Node: Examples<37>,  Prev: tracemalloc C API,  Up: Memory Management

7.11.12 Examples
----------------

Here is the example from section *note Overview: 5238, rewritten so that
the I/O buffer is allocated from the Python heap by using the first
function set:

     PyObject *res;
     char *buf = (char *) PyMem_Malloc(BUFSIZ); /* for I/O */

     if (buf == NULL)
         return PyErr_NoMemory();
     /* ...Do some I/O operation involving buf... */
     res = PyBytes_FromString(buf);
     PyMem_Free(buf); /* allocated with PyMem_Malloc */
     return res;

The same code using the type-oriented function set:

     PyObject *res;
     char *buf = PyMem_New(char, BUFSIZ); /* for I/O */

     if (buf == NULL)
         return PyErr_NoMemory();
     /* ...Do some I/O operation involving buf... */
     res = PyBytes_FromString(buf);
     PyMem_Del(buf); /* allocated with PyMem_New */
     return res;

Note that in the two examples above, the buffer is always manipulated
via functions belonging to the same set.  Indeed, it is required to use
the same memory API family for a given memory block, so that the risk of
mixing different allocators is reduced to a minimum.  The following code
sequence contains two errors, one of which is labeled as 'fatal' because
it mixes two different allocators operating on different heaps.

     char *buf1 = PyMem_New(char, BUFSIZ);
     char *buf2 = (char *) malloc(BUFSIZ);
     char *buf3 = (char *) PyMem_Malloc(BUFSIZ);
     ...
     PyMem_Del(buf3);  /* Wrong -- should be PyMem_Free() */
     free(buf2);       /* Right -- allocated via malloc() */
     free(buf1);       /* Fatal -- should be PyMem_Del()  */

In addition to the functions aimed at handling raw memory blocks from
the Python heap, objects in Python are allocated and released with *note
PyObject_New: 98f, *note PyObject_NewVar: 990. and *note PyObject_Del():
1520.

These will be explained in the next chapter on defining and implementing
new object types in C.


File: python.info,  Node: Object Implementation Support,  Next: API and ABI Versioning,  Prev: Memory Management,  Up: Python/C API Reference Manual

7.12 Object Implementation Support
==================================

This chapter describes the functions, types, and macros used when
defining new object types.

* Menu:

* Allocating Objects on the Heap::
* Common Object Structures::
* Type Object Structures::
* Supporting Cyclic Garbage Collection::


File: python.info,  Node: Allocating Objects on the Heap,  Next: Common Object Structures,  Up: Object Implementation Support

7.12.1 Allocating Objects on the Heap
-------------------------------------

 -- C Function: *note PyObject: 33a. *_PyObject_New (PyTypeObject *type)
     'Return value: New reference.'

 -- C Function: *note PyVarObject: 43a6. *_PyObject_NewVar (PyTypeObject
          *type, Py_ssize_t size)
     'Return value: New reference.'

 -- C Function: *note PyObject: 33a. *PyObject_Init (PyObject *op,
          PyTypeObject *type)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  Initialize a newly allocated object 'op' with its type and
     initial reference.  Returns the initialized object.  Other fields
     of the object are not affected.

 -- C Function: *note PyVarObject: 43a6. *PyObject_InitVar (PyVarObject
          *op, PyTypeObject *type, Py_ssize_t size)
     'Return value: Borrowed reference.''  Part of the *note Stable ABI:
     556.'  This does everything *note PyObject_Init(): a79. does, and
     also initializes the length information for a variable-size object.

 -- C Macro: PyObject_New (TYPE, typeobj)

     Allocate a new Python object using the C structure type 'TYPE' and
     the Python type object 'typeobj' (‘PyTypeObject*’).  Fields not
     defined by the Python object header are not initialized.  The
     caller will own the only reference to the object (i.e.  its
     reference count will be one).  The size of the memory allocation is
     determined from the *note tp_basicsize: 991. field of the type
     object.

     Note that this function is unsuitable if 'typeobj' has *note
     Py_TPFLAGS_HAVE_GC: 780. set.  For such objects, use *note
     PyObject_GC_New(): ab7. instead.

 -- C Macro: PyObject_NewVar (TYPE, typeobj, size)

     Allocate a new Python object using the C structure type 'TYPE' and
     the Python type object 'typeobj' (‘PyTypeObject*’).  Fields not
     defined by the Python object header are not initialized.  The
     allocated memory allows for the 'TYPE' structure plus 'size'
     (‘Py_ssize_t’) fields of the size given by the *note tp_itemsize:
     2121. field of 'typeobj'.  This is useful for implementing objects
     like tuples, which are able to determine their size at construction
     time.  Embedding the array of fields into the same allocation
     decreases the number of allocations, improving the memory
     management efficiency.

     Note that this function is unsuitable if 'typeobj' has *note
     Py_TPFLAGS_HAVE_GC: 780. set.  For such objects, use *note
     PyObject_GC_NewVar(): ab8. instead.

 -- C Variable: *note PyObject: 33a. _Py_NoneStruct

     Object which is visible in Python as ‘None’.  This should only be
     accessed using the *note Py_None: 4b69. macro, which evaluates to a
     pointer to this object.

See also
........

*note Module Objects: 50db.

     To allocate and create extension modules.

* Menu:

* Deprecated aliases: Deprecated aliases<3>.


File: python.info,  Node: Deprecated aliases<3>,  Up: Allocating Objects on the Heap

7.12.1.1 Deprecated aliases
...........................

These are *note soft deprecated: 209. aliases to existing functions and
macros.  They exist solely for backwards compatibility.

Deprecated alias                                       Function
                                                       
--------------------------------------------------------------------------------------------------------------
                                                       
 -- C Macro: PyObject_NEW (type, typeobj)              *note PyObject_New: 98f.
                                                       
                                                       
 -- C Macro: PyObject_NEW_VAR (type, typeobj, n)       *note PyObject_NewVar: 990.
                                                       
                                                       
 -- C Macro: PyObject_INIT (op, typeobj)               *note PyObject_Init(): a79.
                                                       
                                                       
 -- C Macro: PyObject_INIT_VAR (op, typeobj, n)        *note PyObject_InitVar(): 1ae7.
                                                       
                                                       
 -- C Macro: PyObject_MALLOC (n)                       *note PyObject_Malloc(): c89.
                                                       
                                                       
 -- C Macro: PyObject_REALLOC (p, n)                   *note PyObject_Realloc(): 1492.
                                                       
                                                       
 -- C Macro: PyObject_FREE (p)                         *note PyObject_Free(): c86.
                                                       
                                                       
 -- C Macro: PyObject_DEL (p)                          *note PyObject_Free(): c86.
                                                       
                                                       
 -- C Macro: PyObject_Del (p)                          *note PyObject_Free(): c86.
                                                       


File: python.info,  Node: Common Object Structures,  Next: Type Object Structures,  Prev: Allocating Objects on the Heap,  Up: Object Implementation Support

7.12.2 Common Object Structures
-------------------------------

There are a large number of structures which are used in the definition
of object types for Python.  This section describes these structures and
how they are used.

* Menu:

* Base object types and macros::
* Implementing functions and methods::
* Accessing attributes of extension types::


File: python.info,  Node: Base object types and macros,  Next: Implementing functions and methods,  Up: Common Object Structures

7.12.2.1 Base object types and macros
.....................................

All Python objects ultimately share a small number of fields at the
beginning of the object’s representation in memory.  These are
represented by the *note PyObject: 33a. and *note PyVarObject: 43a6.
types, which are defined, in turn, by the expansions of some macros also
used, whether directly or indirectly, in the definition of all other
Python objects.  Additional macros can be found under *note reference
counting: 4ea5.

 -- C Type: type PyObject
     ' Part of the *note Limited API: 556.  (Only some members are part
     of the stable ABI.)' All object types are extensions of this type.
     This is a type which contains the information Python needs to treat
     a pointer to an object as an object.  In a normal “release” build,
     it contains only the object’s reference count and a pointer to the
     corresponding type object.  Nothing is actually declared to be a
     *note PyObject: 33a, but every pointer to a Python object can be
     cast to a *note PyObject: 33a.*.  Access to the members must be
     done by using the macros *note Py_REFCNT: 8b1. and *note Py_TYPE:
     783.

 -- C Type: type PyVarObject
     ' Part of the *note Limited API: 556.  (Only some members are part
     of the stable ABI.)' This is an extension of *note PyObject: 33a.
     that adds the *note ob_size: 4de3. field.  This is only used for
     objects that have some notion of 'length'.  This type does not
     often appear in the Python/C API. Access to the members must be
     done by using the macros *note Py_REFCNT: 8b1, *note Py_TYPE: 783,
     and *note Py_SIZE: 785.

 -- C Macro: PyObject_HEAD

     This is a macro used when declaring new types which represent
     objects without a varying length.  The PyObject_HEAD macro expands
     to:

          PyObject ob_base;

     See documentation of *note PyObject: 33a. above.

 -- C Macro: PyObject_VAR_HEAD

     This is a macro used when declaring new types which represent
     objects with a length that varies from instance to instance.  The
     PyObject_VAR_HEAD macro expands to:

          PyVarObject ob_base;

     See documentation of *note PyVarObject: 43a6. above.

 -- C Variable: *note PyTypeObject: aba. PyBaseObject_Type
     ' Part of the *note Stable ABI: 556.'  The base class of all other
     objects, the same as *note object: a9b. in Python.

 -- C Function: int Py_Is (PyObject *x, PyObject *y)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Test if
     the 'x' object is the 'y' object, the same as ‘x is y’ in Python.

     Added in version 3.10.

 -- C Function: int Py_IsNone (PyObject *x)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Test if
     an object is the ‘None’ singleton, the same as ‘x is None’ in
     Python.

     Added in version 3.10.

 -- C Function: int Py_IsTrue (PyObject *x)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Test if
     an object is the ‘True’ singleton, the same as ‘x is True’ in
     Python.

     Added in version 3.10.

 -- C Function: int Py_IsFalse (PyObject *x)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Test if
     an object is the ‘False’ singleton, the same as ‘x is False’ in
     Python.

     Added in version 3.10.

 -- C Function: *note PyTypeObject: aba. *Py_TYPE (PyObject *o)
     'Return value: Borrowed reference.'  Get the type of the Python
     object 'o'.

     Return a *note borrowed reference: 33f.

     Use the *note Py_SET_TYPE(): 784. function to set an object type.

     Changed in version 3.11: *note Py_TYPE(): 783. is changed to an
     inline static function.  The parameter type is no longer const
     *note PyObject: 33a.*.

 -- C Function: int Py_IS_TYPE (PyObject *o, PyTypeObject *type)

     Return non-zero if the object 'o' type is 'type'.  Return zero
     otherwise.  Equivalent to: ‘Py_TYPE(o) == type’.

     Added in version 3.9.

 -- C Function: void Py_SET_TYPE (PyObject *o, PyTypeObject *type)

     Set the object 'o' type to 'type'.

     Added in version 3.9.

 -- C Function: *note Py_ssize_t: a6e. Py_SIZE (PyVarObject *o)

     Get the size of the Python object 'o'.

     Use the *note Py_SET_SIZE(): 786. function to set an object size.

     Changed in version 3.11: *note Py_SIZE(): 785. is changed to an
     inline static function.  The parameter type is no longer const
     *note PyVarObject: 43a6.*.

 -- C Function: void Py_SET_SIZE (PyVarObject *o, Py_ssize_t size)

     Set the object 'o' size to 'size'.

     Added in version 3.9.

 -- C Macro: PyObject_HEAD_INIT (type)

     This is a macro which expands to initialization values for a new
     *note PyObject: 33a. type.  This macro expands to:

          _PyObject_EXTRA_INIT
          1, type,

 -- C Macro: PyVarObject_HEAD_INIT (type, size)

     This is a macro which expands to initialization values for a new
     *note PyVarObject: 43a6. type, including the *note ob_size: 4de3.
     field.  This macro expands to:

          _PyObject_EXTRA_INIT
          1, type, size,


File: python.info,  Node: Implementing functions and methods,  Next: Accessing attributes of extension types,  Prev: Base object types and macros,  Up: Common Object Structures

7.12.2.2 Implementing functions and methods
...........................................

 -- C Type: type PyCFunction
     ' Part of the *note Stable ABI: 556.'  Type of the functions used
     to implement most Python callables in C. Functions of this type
     take two *note PyObject: 33a.* parameters and return one such
     value.  If the return value is ‘NULL’, an exception shall have been
     set.  If not ‘NULL’, the return value is interpreted as the return
     value of the function as exposed in Python.  The function must
     return a new reference.

     The function signature is:

          PyObject *PyCFunction(PyObject *self,
                                PyObject *args);

 -- C Type: type PyCFunctionWithKeywords
     ' Part of the *note Stable ABI: 556.'  Type of the functions used
     to implement Python callables in C with signature *note
     METH_VARARGS | METH_KEYWORDS: 5271.  The function signature is:

          PyObject *PyCFunctionWithKeywords(PyObject *self,
                                            PyObject *args,
                                            PyObject *kwargs);

 -- C Type: type PyCFunctionFast
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Type of
     the functions used to implement Python callables in C with
     signature *note METH_FASTCALL: 1731.  The function signature is:

          PyObject *PyCFunctionFast(PyObject *self,
                                    PyObject *const *args,
                                    Py_ssize_t nargs);

 -- C Type: type PyCFunctionFastWithKeywords
     ' Part of the *note Stable ABI: 556. since version 3.13.'  Type of
     the functions used to implement Python callables in C with
     signature *note METH_FASTCALL | METH_KEYWORDS: 5272.  The function
     signature is:

          PyObject *PyCFunctionFastWithKeywords(PyObject *self,
                                                PyObject *const *args,
                                                Py_ssize_t nargs,
                                                PyObject *kwnames);

 -- C Type: type PyCMethod

     Type of the functions used to implement Python callables in C with
     signature *note METH_METHOD | METH_FASTCALL | METH_KEYWORDS: 17a1.
     The function signature is:

          PyObject *PyCMethod(PyObject *self,
                              PyTypeObject *defining_class,
                              PyObject *const *args,
                              Py_ssize_t nargs,
                              PyObject *kwnames)

     Added in version 3.9.

 -- C Type: type PyMethodDef
     ' Part of the *note Stable ABI: 556. (including all members).'
     Structure used to describe a method of an extension type.  This
     structure has four fields:

      -- C Member: const char *ml_name

          Name of the method.

      -- C Member: *note PyCFunction: 14c7. ml_meth

          Pointer to the C implementation.

      -- C Member: int ml_flags

          Flags bits indicating how the call should be constructed.

      -- C Member: const char *ml_doc

          Points to the contents of the docstring.

The *note ml_meth: 5273. is a C function pointer.  The functions may be
of different types, but they always return *note PyObject: 33a.*.  If
the function is not of the *note PyCFunction: 14c7, the compiler will
require a cast in the method table.  Even though ‘PyCFunction’ defines
the first parameter as PyObject*, it is common that the method
implementation uses the specific C type of the 'self' object.

The *note ml_flags: 5274. field is a bitfield which can include the
following flags.  The individual flags indicate either a calling
convention or a binding convention.

There are these calling conventions:

 -- C Macro: METH_VARARGS
     ' Part of the *note Stable ABI: 556.'  This is the typical calling
     convention, where the methods have the type *note PyCFunction:
     14c7.  The function expects two *note PyObject: 33a.* values.  The
     first one is the 'self' object for methods; for module functions,
     it is the module object.  The second parameter (often called
     'args') is a tuple object representing all arguments.  This
     parameter is typically processed using *note PyArg_ParseTuple():
     574. or *note PyArg_UnpackTuple(): 1556.

 -- C Macro: METH_KEYWORDS

     Can only be used in certain combinations with other flags: *note
     METH_VARARGS | METH_KEYWORDS: 5271, *note METH_FASTCALL |
     METH_KEYWORDS: 5272. and *note METH_METHOD | METH_FASTCALL |
     METH_KEYWORDS: 17a1.

*note METH_VARARGS: 1558. | *note METH_KEYWORDS: 4b6c.

     Methods with these flags must be of type *note
     PyCFunctionWithKeywords: 4c4d.  The function expects three
     parameters: 'self', 'args', 'kwargs' where 'kwargs' is a dictionary
     of all the keyword arguments or possibly ‘NULL’ if there are no
     keyword arguments.  The parameters are typically processed using
     *note PyArg_ParseTupleAndKeywords(): 386.

 -- C Macro: METH_FASTCALL
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Fast
     calling convention supporting only positional arguments.  The
     methods have the type *note PyCFunctionFast: 4c4b.  The first
     parameter is 'self', the second parameter is a C array of *note
     PyObject: 33a.* values indicating the arguments and the third
     parameter is the number of arguments (the length of the array).

     Added in version 3.7.

     Changed in version 3.10: ‘METH_FASTCALL’ is now part of the *note
     stable ABI: 4c1f.

*note METH_FASTCALL: 1731. | *note METH_KEYWORDS: 4b6c.

     Extension of *note METH_FASTCALL: 1731. supporting also keyword
     arguments, with methods of type *note PyCFunctionFastWithKeywords:
     4c4c.  Keyword arguments are passed the same way as in the *note
     vectorcall protocol: 555.: there is an additional fourth *note
     PyObject: 33a.* parameter which is a tuple representing the names
     of the keyword arguments (which are guaranteed to be strings) or
     possibly ‘NULL’ if there are no keywords.  The values of the
     keyword arguments are stored in the 'args' array, after the
     positional arguments.

     Added in version 3.7.

 -- C Macro: METH_METHOD
     ' Part of the *note Stable ABI: 556. since version 3.7.'  Can only
     be used in the combination with other flags: *note METH_METHOD |
     METH_FASTCALL | METH_KEYWORDS: 17a1.

*note METH_METHOD: 97a. | *note METH_FASTCALL: 1731. | *note METH_KEYWORDS: 4b6c.

     Extension of *note METH_FASTCALL | METH_KEYWORDS: 5272. supporting
     the 'defining class', that is, the class that contains the method
     in question.  The defining class might be a superclass of
     ‘Py_TYPE(self)’.

     The method needs to be of type *note PyCMethod: 767, the same as
     for ‘METH_FASTCALL | METH_KEYWORDS’ with ‘defining_class’ argument
     added after ‘self’.

     Added in version 3.9.

 -- C Macro: METH_NOARGS
     ' Part of the *note Stable ABI: 556.'  Methods without parameters
     don’t need to check whether arguments are given if they are listed
     with the *note METH_NOARGS: 1523. flag.  They need to be of type
     *note PyCFunction: 14c7.  The first parameter is typically named
     'self' and will hold a reference to the module or object instance.
     In all cases the second parameter will be ‘NULL’.

     The function must have 2 parameters.  Since the second parameter is
     unused, *note Py_UNUSED: 1829. can be used to prevent a compiler
     warning.

 -- C Macro: METH_O
     ' Part of the *note Stable ABI: 556.'  Methods with a single object
     argument can be listed with the *note METH_O: 1557. flag, instead
     of invoking *note PyArg_ParseTuple(): 574. with a ‘"O"’ argument.
     They have the type *note PyCFunction: 14c7, with the 'self'
     parameter, and a *note PyObject: 33a.* parameter representing the
     single argument.

These two constants are not used to indicate the calling convention but
the binding when used with methods of classes.  These may not be used
for functions defined for modules.  At most one of these flags may be
set for any given method.

 -- C Macro: METH_CLASS
     ' Part of the *note Stable ABI: 556.'

     The method will be passed the type object as the first parameter
     rather than an instance of the type.  This is used to create 'class
     methods', similar to what is created when using the *note
     classmethod(): 166. built-in function.

 -- C Macro: METH_STATIC
     ' Part of the *note Stable ABI: 556.'

     The method will be passed ‘NULL’ as the first parameter rather than
     an instance of the type.  This is used to create 'static methods',
     similar to what is created when using the *note staticmethod():
     419. built-in function.

One other constant controls whether a method is loaded in place of
another definition with the same method name.

 -- C Macro: METH_COEXIST
     ' Part of the *note Stable ABI: 556.'  The method will be loaded in
     place of existing definitions.  Without 'METH_COEXIST', the default
     is to skip repeated definitions.  Since slot wrappers are loaded
     before the method table, the existence of a 'sq_contains' slot, for
     example, would generate a wrapped method named *note
     __contains__(): 1406. and preclude the loading of a corresponding
     PyCFunction with the same name.  With the flag defined, the
     PyCFunction will be loaded in place of the wrapper object and will
     co-exist with the slot.  This is helpful because calls to
     PyCFunctions are optimized more than wrapper object calls.

 -- C Variable: *note PyTypeObject: aba. PyCMethod_Type

     The type object corresponding to Python C method objects.  This is
     available as *note types.BuiltinMethodType: 2737. in the Python
     layer.

 -- C Function: int PyCMethod_Check (PyObject *op)

     Return true if 'op' is an instance of the *note PyCMethod_Type:
     5276. type or a subtype of it.  This function always succeeds.

 -- C Function: int PyCMethod_CheckExact (PyObject *op)

     This is the same as *note PyCMethod_Check(): 5277, but does not
     account for subtypes.

 -- C Function: *note PyObject: 33a. *PyCMethod_New (PyMethodDef *ml,
          PyObject *self, PyObject *module, PyTypeObject *cls)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.9.'  Turn 'ml' into a Python *note callable: 2acb.
     object.  The caller must ensure that 'ml' outlives the callable.
     Typically, 'ml' is defined as a static variable.

     The 'self' parameter will be passed as the 'self' argument to the C
     function in ‘ml->ml_meth’ when invoked.  'self' can be ‘NULL’.

     The *note callable: 2acb. object’s ‘__module__’ attribute can be
     set from the given 'module' argument.  'module' should be a Python
     string, which will be used as name of the module the function is
     defined in.  If unavailable, it can be set to *note None: 678. or
     ‘NULL’.

     See also
     ........

     *note function.__module__: 20ad.

     The 'cls' parameter will be passed as the 'defining_class' argument
     to the C function.  Must be set if *note METH_METHOD: 97a. is set
     on ‘ml->ml_flags’.

     Added in version 3.9.

 -- C Variable: *note PyTypeObject: aba. PyCFunction_Type
     ' Part of the *note Stable ABI: 556.'  The type object
     corresponding to Python C function objects.  This is available as
     *note types.BuiltinFunctionType: 2736. in the Python layer.

 -- C Function: int PyCFunction_Check (PyObject *op)

     Return true if 'op' is an instance of the *note PyCFunction_Type:
     4c51. type or a subtype of it.  This function always succeeds.

 -- C Function: int PyCFunction_CheckExact (PyObject *op)

     This is the same as *note PyCFunction_Check(): 5279, but does not
     account for subtypes.

 -- C Function: *note PyObject: 33a. *PyCFunction_NewEx (PyMethodDef
          *ml, PyObject *self, PyObject *module)
     'Return value: New reference.''  Part of the *note Stable ABI:
     556.'  Equivalent to ‘PyCMethod_New(ml, self, module, NULL)’.

 -- C Function: *note PyObject: 33a. *PyCFunction_New (PyMethodDef *ml,
          PyObject *self)
     'Return value: New reference.''  Part of the *note Stable ABI: 556.
     since version 3.4.'  Equivalent to ‘PyCMethod_New(ml, self, NULL,
     NULL)’.

 -- C Function: int PyCFunction_GetFlags (PyObject *func)
     ' Part of the *note Stable ABI: 556.'  Get the function’s flags on
     'func' as they were passed to *note ml_flags: 5274.

     If 'func' is not a C function object, this fails with an exception.
     'func' must not be ‘NULL’.

     This function returns the function’s flags on success, and ‘-1’
     with an exception set on failure.

 -- C Function: int PyCFunction_GET_FLAGS (PyObject *func)

     This is the same as *note PyCFunction_GetFlags(): 4c4e, but without
     error or type checking.

 -- C Function: *note PyCFunction: 14c7. PyCFunction_GetFunction
          (PyObject *func)
     ' Part of the *note Stable ABI: 556.'  Get the function pointer on
     'func' as it was passed to *note ml_meth: 5273.

     If 'func' is not a C function object, this fails with an exception.
     'func' must not be ‘NULL’.

     This function returns the function pointer on success, and ‘NULL’
     with an exception set on failure.

 -- C Function: int PyCFunction_GET_FUNCTION (PyObject *func)

     This is the same as *note PyCFunction_GetFunction(): 4c4f, but
     without error or type checking.

 -- C Function: *note PyObject: 33a. *PyCFunction_GetSelf (PyObject
          *func)
     ' Part of the *note Stable ABI: 556.'  Get the “self” object on
     'func'.  This is the object that would be passed to the first
     argument of a *note PyCFunction: 14c7.  For C function objects
     created through a *note PyMethodDef: 1526. on a *note PyModuleDef:
     987, this is the resulting module object.

     If 'func' is not a C function object, this fails with an exception.
     'func' must not be ‘NULL’.

     This function returns a *note borrowed reference: 33f. to the
     “self” object on success, and ‘NULL’ with an exception set on
     failure.

 -- C Function: *note PyObject: 33a. *PyCFunction_GET_SELF (PyObject
          *func)

     This is the same as *note PyCFunction_GetSelf(): 4c50, but without
     error or type checking.


File: python.info,  Node: Accessing attributes of extension types,  Prev: Implementing functions and methods,  Up: Common Object Structures

7.12.2.3 Accessing attributes of extension types
................................................

 -- C Type: type PyMemberDef
     ' Part of the *note Stable ABI: 556. (including all members).'
     Structure which describes an attribute of a type which corresponds
     to a C struct member.  When defining a class, put a NULL-terminated
     array of these structures in the *note tp_members: 4b9c. slot.

     Its fields are, in order:

      -- C Member: const char *name

          Name of the member.  A NULL value marks the end of a
          ‘PyMemberDef[]’ array.

          The string should be static, no copy is made of it.

      -- C Member: int type

          The type of the member in the C struct.  See *note Member
          types: 1786. for the possible values.

      -- C Member: *note Py_ssize_t: a6e. offset

          The offset in bytes that the member is located on the type’s
          object struct.

      -- C Member: int flags

          Zero or more of the *note Member flags: 5281, combined using
          bitwise OR.

      -- C Member: const char *doc

          The docstring, or NULL. The string should be static, no copy
          is made of it.  Typically, it is defined using *note
          PyDoc_STR: 193c.

     By default (when *note flags: 4bb5. is ‘0’), members allow both
     read and write access.  Use the *note Py_READONLY: 594. flag for
     read-only access.  Certain types, like *note Py_T_STRING: 4e01,
     imply ‘Py_READONLY’.  Only *note Py_T_OBJECT_EX: 597. (and legacy
     *note T_OBJECT: 596.) members can be deleted.  For heap-allocated
     types (created using *note PyType_FromSpec(): 580. or similar),
     ‘PyMemberDef’ may contain a definition for the special member
     ‘"__vectorcalloffset__"’, corresponding to *note
     tp_vectorcall_offset: 4f46. in type objects.  These must be defined
     with ‘Py_T_PYSSIZET’ and ‘Py_READONLY’, for example:

          static PyMemberDef spam_type_members[] = {
              {"__vectorcalloffset__", Py_T_PYSSIZET,
               offsetof(Spam_object, vectorcall), Py_READONLY},
              {NULL}  /* Sentinel */
          };

     (You may need to ‘#include <stddef.h>’ for ‘offsetof()’.)

     The legacy offsets *note tp_dictoffset: 4fa1. and *note
     tp_weaklistoffset: 992. can be defined similarly using
     ‘"__dictoffset__"’ and ‘"__weaklistoffset__"’ members, but
     extensions are strongly encouraged to use *note
     Py_TPFLAGS_MANAGED_DICT: 36e. and *note Py_TPFLAGS_MANAGED_WEAKREF:
     55d. instead.

     Changed in version 3.12: ‘PyMemberDef’ is always available.
     Previously, it required including ‘"structmember.h"’.

 -- C Function: *note PyObject: 33a. *PyMember_GetOne (const char
          *obj_addr, struct PyMemberDef *m)
     ' Part of the *note Stable ABI: 556.'  Get an attribute belonging
     to the object at address 'obj_addr'.  The attribute is described by
     ‘PyMemberDef’ 'm'.  Returns ‘NULL’ on error.

     Changed in version 3.12: ‘PyMember_GetOne’ is always available.
     Previously, it required including ‘"structmember.h"’.

 -- C Function: int PyMember_SetOne (char *obj_addr, struct PyMemberDef
          *m, PyObject *o)
     ' Part of the *note Stable ABI: 556.'  Set an attribute belonging
     to the object at address 'obj_addr' to object 'o'.  The attribute
     to set is described by ‘PyMemberDef’ 'm'.  Returns ‘0’ if
     successful and a negative value on failure.

     Changed in version 3.12: ‘PyMember_SetOne’ is always available.
     Previously, it required including ‘"structmember.h"’.

* Menu:

* Member flags::
* Member types::
* Defining Getters and Setters::


File: python.info,  Node: Member flags,  Next: Member types,  Up: Accessing attributes of extension types

7.12.2.4 Member flags
.....................

The following flags can be used with *note PyMemberDef.flags: 4bb5.:

 -- C Macro: Py_READONLY
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Not
     writable.

 -- C Macro: Py_AUDIT_READ
     ' Part of the *note Stable ABI: 556. since version 3.12.'  Emit an
     ‘object.__getattr__’ *note audit event: 19b7. before reading.

 -- C Macro: Py_RELATIVE_OFFSET
     ' Part of the *note Stable ABI: 556. since version 3.12.'
     Indicates that the *note offset: 5280. of this ‘PyMemberDef’ entry
     indicates an offset from the subclass-specific data, rather than
     from ‘PyObject’.

     Can only be used as part of *note Py_tp_members: 4b9c. *note slot:
     4da4. when creating a class using negative *note basicsize: 54b.
     It is mandatory in that case.

     This flag is only used in *note PyType_Slot: 4da4.  When setting
     *note tp_members: 4b9c. during class creation, Python clears it and
     sets *note PyMemberDef.offset: 5280. to the offset from the
     ‘PyObject’ struct.

Changed in version 3.10: The ‘RESTRICTED’, ‘READ_RESTRICTED’ and
‘WRITE_RESTRICTED’ macros available with ‘#include "structmember.h"’ are
deprecated.  ‘READ_RESTRICTED’ and ‘RESTRICTED’ are equivalent to *note
Py_AUDIT_READ: 595.; ‘WRITE_RESTRICTED’ does nothing.

Changed in version 3.12: The ‘READONLY’ macro was renamed to *note
Py_READONLY: 594.  The ‘PY_AUDIT_READ’ macro was renamed with the ‘Py_’
prefix.  The new names are now always available.  Previously, these
required ‘#include "structmember.h"’.  The header is still available and
it provides the old names.


File: python.info,  Node: Member types,  Next: Defining Getters and Setters,  Prev: Member flags,  Up: Accessing attributes of extension types

7.12.2.5 Member types
.....................

*note PyMemberDef.type: 4bb4. can be one of the following macros
corresponding to various C types.  When the member is accessed in
Python, it will be converted to the equivalent Python type.  When it is
set from Python, it will be converted back to the C type.  If that is
not possible, an exception such as *note TypeError: 2c3. or *note
ValueError: 202. is raised.

Unless marked (D), attributes defined this way cannot be deleted using
e.g.  *note del: 18c2. or *note delattr(): 230f.

Macro name                           C type                            Python type
                                                                       
--------------------------------------------------------------------------------------------------
                                                                       
 -- C Macro: Py_T_BYTE               char                              *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_SHORT              short                             *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_INT                int                               *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_LONG               long                              *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_LONGLONG           long long                         *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_UBYTE              unsigned char                     *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_UINT               unsigned int                      *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_USHORT             unsigned short                    *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_ULONG              unsigned long                     *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_ULONGLONG          unsigned long long                *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_PYSSIZET           *note Py_ssize_t: a6e.            *note int: 257.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_FLOAT              float                             *note float: 2f7.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_DOUBLE             double                            *note float: 2f7.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_BOOL               char (written as 0 or 1)          *note bool: 46b.
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_STRING             const char* (*)                   *note str: 44f. (RO)
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_STRING_INPLACE     const char[] (*)                  *note str: 44f. (RO)
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_CHAR               char (0-127)                      *note str: 44f. (**)
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

 -- C Macro: Py_T_OBJECT_EX          *note PyObject: 33a.*             *note object: a9b. (D)
     ' Part of the                                                     
     *note Stable ABI: 556. since
     version 3.12.'

     (*): Zero-terminated, UTF8-encoded C string.  With ‘Py_T_STRING’
     the C representation is a pointer; with ‘Py_T_STRING_INPLACE’ the
     string is stored directly in the structure.

     (**): String of length 1.  Only ASCII is accepted.

     (RO): Implies *note Py_READONLY: 594.

     (D): Can be deleted, in which case the pointer is set to ‘NULL’.
     Reading a ‘NULL’ pointer raises *note AttributeError: 34e.

Added in version 3.12: In previous versions, the macros were only
available with ‘#include "structmember.h"’ and were named without the
‘Py_’ prefix (e.g.  as ‘T_INT’).  The header is still available and
contains the old names, along with the following deprecated types:

 -- C Macro: T_OBJECT

     Like ‘Py_T_OBJECT_EX’, but ‘NULL’ is converted to ‘None’.  This
     results in surprising behavior in Python: deleting the attribute
     effectively sets it to ‘None’.

 -- C Macro: T_NONE

     Always ‘None’.  Must be used with *note Py_READONLY: 594.


File: python.info,  Node: Defining Getters and Setters,  Prev: Member types,  Up: Accessing attributes of extension types

7.12.2.6 Defining Getters and Setters
.....................................

 -- C Type: type PyGetSetDef
     ' Part of the *note Stable ABI: 556. (including all members).'
     Structure to define property-like access for a type.  See also
     description of the *note PyTypeObject.tp_getset: 4ba1. slot.

      -- C Member: const char *name

          attribute name

      -- C Member: *note getter: 4e66. get

          C function to get the attribute.

      -- C Member: *note setter: 4e74. set

          Optional C function to set or delete the attribute.  If
          ‘NULL’, the attribute is read-only.

      -- C Member: const char *doc

          optional docstring

      -- C Member: void *closure

          Optional user data pointer, providing additional data for
          getter and setter.

 -- C Type: typedef *note PyObject: 33a. *(*getter)(*note PyObject:
          33a.*, void*)
     ' Part of the *note Stable ABI: 556.'  The ‘get’ function takes one
     *note PyObject: 33a.* parameter (the instance) and a user data
     pointer (the associated ‘closure’):

     It should return a new reference on success or ‘NULL’ with a set
     exception on failure.

 -- C Type: typedef int (*setter)(*note PyObject: 33a.*, *note PyObject:
          33a.*, void*)
     ' Part of the *note Stable ABI: 556.'  ‘set’ functions take two
     *note PyObject: 33a.* parameters (the instance and the value to be
     set) and a user data pointer (the associated ‘closure’):

     In case the attribute should be deleted the second parameter is
     ‘NULL’.  Should return ‘0’ on success or ‘-1’ with a set exception
     on failure.


File: python.info,  Node: Type Object Structures,  Next: Supporting Cyclic Garbage Collection,  Prev: Common Object Structures,  Up: Object Implementation Support

7.12.3 Type Object Structures
-----------------------------

Perhaps one of the most important structures of the Python object system
is the structure that defines a new type: the *note PyTypeObject: aba.
structure.  Type objects can be handled using any of the ‘PyObject_*’ or
‘PyType_*’ functions, but do not offer much that’s interesting to most
Python applications.  These objects are fundamental to how objects
behave, so they are very important to the interpreter itself and to any
extension module that implements new types.

Type objects are fairly large compared to most of the standard types.
The reason for the size is that each type object stores a large number
of values, mostly C function pointers, each of which implements a small
part of the type’s functionality.  The fields of the type object are
examined in detail in this section.  The fields will be described in the
order in which they occur in the structure.

In addition to the following quick reference, the *note Examples: 528e.
section provides at-a-glance insight into the meaning and use of *note
PyTypeObject: aba.

* Menu:

* Quick Reference::
* PyTypeObject Definition::
* PyObject Slots::
* PyVarObject Slots::
* PyTypeObject Slots::
* Static Types::
* Heap Types::
* Number Object Structures::
* Mapping Object Structures::
* Sequence Object Structures::
* Buffer Object Structures::
* Async Object Structures::
* Slot Type typedefs::
* Examples: Examples<38>.


File: python.info,  Node: Quick Reference,  Next: PyTypeObject Definition,  Up: Type Object Structures

7.12.3.1 Quick Reference
........................

* Menu:

* “tp slots”::
* sub-slots::
* slot typedefs::


File: python.info,  Node: “tp slots”,  Next: sub-slots,  Up: Quick Reference

7.12.3.2 “tp slots”
...................

PyTypeObject Slot      *note Type: 5292.      special                Info
(1)                                           methods/attrs          (2)
                                                                     
---------------------------------------------------------------------------------------------
                                                                     
O                      T                      D                      I
                                                                     
                                                                                       
<R>                    const char *           __name__               X     X
*note tp_name: 1a56.                                                       

*note tp_basicsize: 991.*note Py_ssize_t: a6e.                       X     X           X
                                                                                       
                                                                                       
*note tp_itemsize: 2121.*note Py_ssize_t: a6e.                             X           X
                                                                                       
                                                                                       
*note tp_dealloc: 4b87.*note destructor: 4e61.                       X     X           X
                                                                                       
                                                                                       
*note tp_vectorcall_offset: 4f46.*note Py_ssize_t: a6e.                    X           X
                                                                                       
                                                                                       
(*note tp_getattr: 4bb7.)*note getattrfunc: 4e62.__getattribute__,                     G
                                              __getattr__                              
                                              
                                                                                       
(*note tp_setattr: 4bb8.)*note setattrfunc: 4e72.__setattr__,                          G
                                              __delattr__                              
                                              
                                                                                       
*note tp_as_async: f03.*note PyAsyncMethods: 4f9f.*note sub-slots: 5293.               %
                       *                                                               
                       
                                                                                       
*note tp_repr: 4bae.   *note reprfunc: 4e70.  __repr__               X     X           X
                                                                                       
                                                                                       
*note tp_as_number: 995.*note PyNumberMethods: 146c.*note sub-slots: 5293.             %
                       *                                                               
                       
                                                                                       
*note tp_as_sequence: 5294.*note PySequenceMethods: 4bbe.*note sub-slots: 5293.        %
                       *                                                               
                       
                                                                                       
*note tp_as_mapping: 5295.*note PyMappingMethods: 4bbf.*note sub-slots: 5293.          %
                       *                                                               
                       
                                                                                       
*note tp_hash: 4bc0.   *note hashfunc: 4e67.  __hash__               X                 G
                                                                                       
                                                                                       
*note tp_call: 55c.    *note ternaryfunc: 4e77.__call__                    X           X
                                                                                       
                                                                                       
*note tp_str: 4baf.    *note reprfunc: 4e70.  __str__                X                 X
                                                                                       
                                                                                       
*note tp_getattro: 1803.*note getattrofunc: 4e63.__getattribute__,   X     X           G
                                              __getattr__                              
                                              
                                                                                       
*note tp_setattro: 4bb2.*note setattrofunc: 4e73.__setattr__,        X     X           G
                                              __delattr__                              
                                              
                                                                                       
*note tp_as_buffer: 993.*note PyBufferProcs: 4fa7.*note sub-slots: 5293.               %
                       *                                                               
                       
                                                                                       
*note tp_flags: 1a18.  unsigned long                                 X     X           ?
                                                                                       
                                                                                       
*note tp_doc: 4b96.    const char *           __doc__                X     X
                                                                           
                                                                                       
*note tp_traverse: 781.*note traverseproc: 4e78.                           X           G
                                                                                       
                                                                                       
*note tp_clear: 4bac.  *note inquiry: 4e69.                                X           G
                                                                                       
                                                                                       
*note tp_richcompare: 4bba.*note richcmpfunc: 4e71.__lt__, __le__,   X                 G
                                              __eq__, __ne__,                          
                                              __gt__, __ge__
                                              
                                                                                       
(*note tp_weaklistoffset: 992.)*note Py_ssize_t: a6e.                      X           ?
                                                                                       
                                                                                       
*note tp_iter: 153e.   *note getiterfunc: 4e65.__iter__                                X
                                                                                       
                                                                                       
*note tp_iternext: 153f.*note iternextfunc: 4e6a.__next__                              X
                                                                                       
                                                                                       
*note tp_methods: 4b9e.*note PyMethodDef: 1526.                      X     X
                       []                                                  
                       
                                                                                       
*note tp_members: 4b9c.*note PyMemberDef: 552.                             X
                       []                                                  
                       
                                                                                       
*note tp_getset: 4ba1. *note PyGetSetDef: bd7.                       X     X
                       []                                                  
                       
                                                                                       
*note tp_base: 20d7.   *note PyTypeObject: aba.__base__                          X
                       *                                                         
                       
                                                                                       
*note tp_dict: 182b.   *note PyObject: 33a.   __dict__                           ?
                       *                                                         
                       
                                                                                       
*note tp_descr_get: 5296.*note descrgetfunc: 4e5f.__get__                              X
                                                                                       
                                                                                       
*note tp_descr_set: 1a5a.*note descrsetfunc: 4e60.__set__, __delete__                  X
                                                                                       
                                                                                       
(*note tp_dictoffset: 4fa1.)*note Py_ssize_t: a6e.                         X           ?
                                                                                       
                                                                                       
*note tp_init: 584.    *note initproc: 4e68.  __init__               X     X           X
                                                                                       
                                                                                       
*note tp_alloc: 4b9b.  *note allocfunc: 4e5d.                        X           ?     ?
                                                                                       
                                                                                       
*note tp_new: 582.     *note newfunc: 4e6c.   __new__                X     X     ?     ?
                                                                                       
                                                                                       
*note tp_free: 4b9a.   *note freefunc: 50e7.                         X     X     ?     ?
                                                                                       
                                                                                       
*note tp_is_gc: 5297.  *note inquiry: 4e69.                                X           X
                                                                                       
                                                                                       
<*note tp_bases: 5298.>*note PyObject: 33a.   __bases__                          ~
                       *                                                         
                       
                                                                                       
<*note tp_mro: 4fa4.>  *note PyObject: 33a.   __mro__                            ~
                       *                                                         
                       
                                                                                       
[*note tp_cache: 4fa5.]*note PyObject: 33a.
                       *
                       
                                                                                       
[*note tp_subclasses: 575.]void *             __subclasses__
                                              
                                                                                       
[*note tp_weaklist: 4fa6.]*note PyObject: 33a.
                       *
                       
                                                                                       
(*note tp_del: 5299.)  *note destructor: 4e61.
                       
                                                                                       
[*note tp_version_tag: 529a.]unsigned int
                       
                                                                                       
*note tp_finalize: abb.*note destructor: 4e61.__del__                                  X
                                                                                       
                                                                                       
*note tp_vectorcall: 4fa3.*note vectorcallfunc: 55a.
                       
                                                                                       
[*note tp_watched: 529b.]unsigned char
                       

   ---------- Footnotes ----------

   (1) '()': A slot name in parentheses indicates it is (effectively)
deprecated.

'<>': Names in angle brackets should be initially set to ‘NULL’ and
treated as read-only.

'[]': Names in square brackets are for internal use only.

'<R>' (as a prefix) means the field is required (must be non-‘NULL’).

   (2) Columns:

'“O”': set on *note PyBaseObject_Type: 4c37.

'“T”': set on *note PyType_Type: 550.

'“D”': default (if slot is set to ‘NULL’)

     X - PyType_Ready sets this value if it is NULL
     ~ - PyType_Ready always sets this value (it should be NULL)
     ? - PyType_Ready may set this value depending on other slots

     Also see the inheritance column ("I").

'“I”': inheritance

     X - type slot is inherited via *PyType_Ready* if defined with a *NULL* value
     % - the slots of the sub-struct are inherited individually
     G - inherited, but only in combination with other slots; see the slot's description
     ? - it's complicated; see the slot's description

Note that some slots are effectively inherited through the normal
attribute lookup chain.


File: python.info,  Node: sub-slots,  Next: slot typedefs,  Prev: “tp slots”,  Up: Quick Reference

7.12.3.3 sub-slots
..................

Slot                           *note Type: 5292.     special
                                                     methods
                                                     
----------------------------------------------------------------------
                                                     
*note am_await: 529d.          *note unaryfunc: 4e79.__await__
                                                     
                                                     
*note am_aiter: 529e.          *note unaryfunc: 4e79.__aiter__
                                                     
                                                     
*note am_anext: 529f.          *note unaryfunc: 4e79.__anext__
                                                     
                                                     
*note am_send: 52a0.           *note sendfunc: 52a1.
                               
                                                     
                                                     
*note nb_add: 4f96.            *note binaryfunc: 4e5e.__add__
                                                     __radd__
                                                     
                                                     
*note nb_inplace_add: 52a2.    *note binaryfunc: 4e5e.__iadd__
                                                     
                                                     
*note nb_subtract: 52a3.       *note binaryfunc: 4e5e.__sub__
                                                     __rsub__
                                                     
                                                     
*note nb_inplace_subtract: 52a4.*note binaryfunc: 4e5e.__isub__
                                                     
                                                     
*note nb_multiply: 52a5.       *note binaryfunc: 4e5e.__mul__
                                                     __rmul__
                                                     
                                                     
*note nb_inplace_multiply: 52a6.*note binaryfunc: 4e5e.__imul__
                                                     
                                                     
*note nb_remainder: 52a7.      *note binaryfunc: 4e5e.__mod__
                                                     __rmod__
                                                     
                                                     
*note nb_inplace_remainder: 52a8.*note binaryfunc: 4e5e.__imod__
                                                     
                                                     
*note nb_divmod: 52a9.         *note binaryfunc: 4e5e.__divmod__
                                                     __rdivmod__
                                                     
                                                     
*note nb_power: 52aa.          *note ternaryfunc: 4e77.__pow__
                                                     __rpow__
                                                     
                                                     
*note nb_inplace_power: 52ab.  *note ternaryfunc: 4e77.__ipow__
                                                     
                                                     
*note nb_negative: 52ac.       *note unaryfunc: 4e79.__neg__
                                                     
                                                     
*note nb_positive: 52ad.       *note unaryfunc: 4e79.__pos__
                                                     
                                                     
*note nb_absolute: 52ae.       *note unaryfunc: 4e79.__abs__
                                                     
                                                     
*note nb_bool: 52af.           *note inquiry: 4e69.  __bool__
                                                     
                                                     
*note nb_invert: 52b0.         *note unaryfunc: 4e79.__invert__
                                                     
                                                     
*note nb_lshift: 52b1.         *note binaryfunc: 4e5e.__lshift__
                                                     __rlshift__
                                                     
                                                     
*note nb_inplace_lshift: 52b2. *note binaryfunc: 4e5e.__ilshift__
                                                     
                                                     
*note nb_rshift: 52b3.         *note binaryfunc: 4e5e.__rshift__
                                                     __rrshift__
                                                     
                                                     
*note nb_inplace_rshift: 52b4. *note binaryfunc: 4e5e.__irshift__
                                                     
                                                     
*note nb_and: 52b5.            *note binaryfunc: 4e5e.__and__
                                                     __rand__
                                                     
                                                     
*note nb_inplace_and: 52b6.    *note binaryfunc: 4e5e.__iand__
                                                     
                                                     
*note nb_xor: 52b7.            *note binaryfunc: 4e5e.__xor__
                                                     __rxor__
                                                     
                                                     
*note nb_inplace_xor: 52b8.    *note binaryfunc: 4e5e.__ixor__
                                                     
                                                     
*note nb_or: 52b9.             *note binaryfunc: 4e5e.__or__ __ror__
                                                     
                                                     
*note nb_inplace_or: 52ba.     *note binaryfunc: 4e5e.__ior__
                                                     
                                                     
*note nb_int: 52bb.            *note unaryfunc: 4e79.__int__
                                                     
                                                     
*note nb_reserved: 52bc.       void *
                               
                                                     
*note nb_float: 52bd.          *note unaryfunc: 4e79.__float__
                                                     
                                                     
*note nb_floor_divide: 52be.   *note binaryfunc: 4e5e.__floordiv__
                                                     
                                                     
*note nb_inplace_floor_divide: 52bf.*note binaryfunc: 4e5e.__ifloordiv__
                                                     
                                                     
*note nb_true_divide: 52c0.    *note binaryfunc: 4e5e.__truediv__
                                                     
                                                     
*note nb_inplace_true_divide: 52c1.*note binaryfunc: 4e5e.__itruediv__
                                                     
                                                     
*note nb_index: 146b.          *note unaryfunc: 4e79.__index__
                                                     
                                                     
*note nb_matrix_multiply: 52c2.*note binaryfunc: 4e5e.__matmul__
                                                     __rmatmul__
                                                     
                                                     
*note nb_inplace_matrix_multiply: 52c3.*note binaryfunc: 4e5e.__imatmul__
                                                     
                                                     
                                                     
*note mp_length: 52c4.         *note lenfunc: 4e6b.  __len__
                                                     
                                                     
*note mp_subscript: 1a9d.      *note binaryfunc: 4e5e.__getitem__
                                                     
                                                     
*note mp_ass_subscript: 52c5.  *note objobjargproc: 4e6d.__setitem__,
                                                     __delitem__
                                                     
                                                     
                                                     
*note sq_length: 4fa0.         *note lenfunc: 4e6b.  __len__
                                                     
                                                     
*note sq_concat: 52c6.         *note binaryfunc: 4e5e.__add__
                                                     
                                                     
*note sq_repeat: 52c7.         *note ssizeargfunc: 4e75.__mul__
                                                     
                                                     
*note sq_item: 1a9c.           *note ssizeargfunc: 4e75.__getitem__
                                                     
                                                     
*note sq_ass_item: 52c8.       *note ssizeobjargproc: 4e76.__setitem__
                                                     __delitem__
                                                     
                                                     
*note sq_contains: 52c9.       *note objobjproc: 4e6e.__contains__
                                                     
                                                     
*note sq_inplace_concat: 52ca. *note binaryfunc: 4e5e.__iadd__
                                                     
                                                     
*note sq_inplace_repeat: 52cb. *note ssizeargfunc: 4e75.__imul__
                                                     
                                                     
                                                     
*note bf_getbuffer: 765.       *note getbufferproc(): 4e64.__buffer__
                                                     
                                                     
*note bf_releasebuffer: 766.   *note releasebufferproc(): 4e6f.__release_buffer__
                                                     


File: python.info,  Node: slot typedefs,  Prev: sub-slots,  Up: Quick Reference

7.12.3.4 slot typedefs
......................

typedef                           Parameter Types                   Return Type
                                                                    
-----------------------------------------------------------------------------------------------
                                                                    
*note allocfunc: 4e5d.                 *note PyTypeObject: aba. *   *note PyObject: 33a. *
                                       *note Py_ssize_t: a6e.       
                                  
                                                                    
*note destructor: 4e61.           *note PyObject: 33a. *            void
                                                                    
                                                                    
*note freefunc: 50e7.             void *                            void
                                                                    
                                                                    
*note traverseproc: 4e78.              *note PyObject: 33a. *       int
                                       *note visitproc: 4e7a.       
                                       void *
                                  
                                                                    
*note newfunc: 4e6c.                   *note PyTypeObject: aba. *   *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note initproc: 4e68.                  *note PyObject: 33a. *       int
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note reprfunc: 4e70.             *note PyObject: 33a. *            *note PyObject: 33a. *
                                                                    
                                                                    
*note getattrfunc: 4e62.               *note PyObject: 33a. *       *note PyObject: 33a. *
                                       const char *                 
                                  
                                                                    
*note setattrfunc: 4e72.               *note PyObject: 33a. *       int
                                       const char *                 
                                       *note PyObject: 33a. *
                                  
                                                                    
*note getattrofunc: 4e63.              *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                  
                                                                    
*note setattrofunc: 4e73.              *note PyObject: 33a. *       int
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note descrgetfunc: 4e5f.              *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note descrsetfunc: 4e60.              *note PyObject: 33a. *       int
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note hashfunc: 4e67.             *note PyObject: 33a. *            Py_hash_t
                                                                    
                                                                    
*note richcmpfunc: 4e71.               *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                       int
                                  
                                                                    
*note getiterfunc: 4e65.          *note PyObject: 33a. *            *note PyObject: 33a. *
                                                                    
                                                                    
*note iternextfunc: 4e6a.         *note PyObject: 33a. *            *note PyObject: 33a. *
                                                                    
                                                                    
*note lenfunc: 4e6b.              *note PyObject: 33a. *            *note Py_ssize_t: a6e.
                                                                    
                                                                    
*note getbufferproc: 4e64.             *note PyObject: 33a. *       int
                                       *note Py_buffer: 75b. *      
                                       int
                                  
                                                                    
*note releasebufferproc: 4e6f.         *note PyObject: 33a. *       void
                                       *note Py_buffer: 75b. *      
                                  
                                                                    
*note inquiry: 4e69.              *note PyObject: 33a. *            int
                                                                    
                                                                    
*note unaryfunc: 4e79.                 *note PyObject: 33a. *       *note PyObject: 33a. *
                                                                    
                                                                    
*note binaryfunc: 4e5e.                *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                  
                                                                    
*note ternaryfunc: 4e77.               *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note ssizeargfunc: 4e75.              *note PyObject: 33a. *       *note PyObject: 33a. *
                                       *note Py_ssize_t: a6e.       
                                  
                                                                    
*note ssizeobjargproc: 4e76.           *note PyObject: 33a. *       int
                                       *note Py_ssize_t: a6e.       
                                       *note PyObject: 33a. *
                                  
                                                                    
*note objobjproc: 4e6e.                *note PyObject: 33a. *       int
                                       *note PyObject: 33a. *       
                                  
                                                                    
*note objobjargproc: 4e6d.             *note PyObject: 33a. *       int
                                       *note PyObject: 33a. *       
                                       *note PyObject: 33a. *
                                  

See *note Slot Type typedefs: 52cd. below for more detail.


File: python.info,  Node: PyTypeObject Definition,  Next: PyObject Slots,  Prev: Quick Reference,  Up: Type Object Structures

7.12.3.5 PyTypeObject Definition
................................

The structure definition for *note PyTypeObject: aba. can be found in
‘Include/cpython/object.h’.  For convenience of reference, this repeats
the definition found there:

     typedef struct _typeobject {
         PyObject_VAR_HEAD
         const char *tp_name; /* For printing, in format "<module>.<name>" */
         Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

         /* Methods to implement standard operations */

         destructor tp_dealloc;
         Py_ssize_t tp_vectorcall_offset;
         getattrfunc tp_getattr;
         setattrfunc tp_setattr;
         PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
                                         or tp_reserved (Python 3) */
         reprfunc tp_repr;

         /* Method suites for standard classes */

         PyNumberMethods *tp_as_number;
         PySequenceMethods *tp_as_sequence;
         PyMappingMethods *tp_as_mapping;

         /* More standard operations (here for binary compatibility) */

         hashfunc tp_hash;
         ternaryfunc tp_call;
         reprfunc tp_str;
         getattrofunc tp_getattro;
         setattrofunc tp_setattro;

         /* Functions to access object as input/output buffer */
         PyBufferProcs *tp_as_buffer;

         /* Flags to define presence of optional/expanded features */
         unsigned long tp_flags;

         const char *tp_doc; /* Documentation string */

         /* Assigned meaning in release 2.0 */
         /* call function for all accessible objects */
         traverseproc tp_traverse;

         /* delete references to contained objects */
         inquiry tp_clear;

         /* Assigned meaning in release 2.1 */
         /* rich comparisons */
         richcmpfunc tp_richcompare;

         /* weak reference enabler */
         Py_ssize_t tp_weaklistoffset;

         /* Iterators */
         getiterfunc tp_iter;
         iternextfunc tp_iternext;

         /* Attribute descriptor and subclassing stuff */
         struct PyMethodDef *tp_methods;
         struct PyMemberDef *tp_members;
         struct PyGetSetDef *tp_getset;
         // Strong reference on a heap type, borrowed reference on a static type
         struct _typeobject *tp_base;
         PyObject *tp_dict;
         descrgetfunc tp_descr_get;
         descrsetfunc tp_descr_set;
         Py_ssize_t tp_dictoffset;
         initproc tp_init;
         allocfunc tp_alloc;
         newfunc tp_new;
         freefunc tp_free; /* Low-level free-memory routine */
         inquiry tp_is_gc; /* For PyObject_IS_GC */
         PyObject *tp_bases;
         PyObject *tp_mro; /* method resolution order */
         PyObject *tp_cache;
         PyObject *tp_subclasses;
         PyObject *tp_weaklist;
         destructor tp_del;

         /* Type attribute cache version tag. Added in version 2.6 */
         unsigned int tp_version_tag;

         destructor tp_finalize;
         vectorcallfunc tp_vectorcall;

         /* bitset of which type-watchers care about this type */
         unsigned char tp_watched;
     } PyTypeObject;


File: python.info,  Node: PyObject Slots,  Next: PyVarObject Slots,  Prev: PyTypeObject Definition,  Up: Type Object Structures

7.12.3.6 PyObject Slots
.......................

The type object structure extends the *note PyVarObject: 43a6.
structure.  The *note ob_size: 4de3. field is used for dynamic types
(created by ‘type_new()’, usually called from a class statement).  Note
that *note PyType_Type: 550. (the metatype) initializes *note
tp_itemsize: 2121, which means that its instances (i.e.  type objects)
'must' have the ‘ob_size’ field.

 -- C Member: *note Py_ssize_t: a6e. *note PyObject: 33a.ob_refcnt
     ' Part of the *note Stable ABI: 556.'  This is the type object’s
     reference count, initialized to ‘1’ by the ‘PyObject_HEAD_INIT’
     macro.  Note that for *note statically allocated type objects: 782,
     the type’s instances (objects whose *note ob_type: 4b98. points
     back to the type) do 'not' count as references.  But for *note
     dynamically allocated type objects: 96f, the instances 'do' count
     as references.

     'Inheritance:'

     This field is not inherited by subtypes.

 -- C Member: *note PyTypeObject: aba. **note PyObject: 33a.ob_type
     ' Part of the *note Stable ABI: 556.'  This is the type’s type, in
     other words its metatype.  It is initialized by the argument to the
     ‘PyObject_HEAD_INIT’ macro, and its value should normally be
     ‘&PyType_Type’.  However, for dynamically loadable extension
     modules that must be usable on Windows (at least), the compiler
     complains that this is not a valid initializer.  Therefore, the
     convention is to pass ‘NULL’ to the ‘PyObject_HEAD_INIT’ macro and
     to initialize this field explicitly at the start of the module’s
     initialization function, before doing anything else.  This is
     typically done like this:

          Foo_Type.ob_type = &PyType_Type;

     This should be done before any instances of the type are created.
     *note PyType_Ready(): 77f. checks if *note ob_type: 4b98. is
     ‘NULL’, and if so, initializes it to the ‘ob_type’ field of the
     base class.  ‘PyType_Ready()’ will not change this field if it is
     non-zero.

     'Inheritance:'

     This field is inherited by subtypes.


File: python.info,  Node: PyVarObject Slots,  Next: PyTypeObject Slots,  Prev: PyObject Slots,  Up: Type Object Structures

7.12.3.7 PyVarObject Slots
..........................

 -- C Member: *note Py_ssize_t: a6e. *note PyVarObject: 43a6.ob_size
     ' Part of the *note Stable ABI: 556.'  For *note statically
     allocated type objects: 782, this should be initialized to zero.
     For *note dynamically allocated type objects: 96f, this field has a
     special internal meaning.

     This field should be accessed using the *note Py_SIZE(): 785. and
     *note Py_SET_SIZE(): 786. macros.

     'Inheritance:'

     This field is not inherited by subtypes.


File: python.info,  Node: PyTypeObject Slots,  Next: Static Types,  Prev: PyVarObject Slots,  Up: Type Object Structures

7.12.3.8 PyTypeObject Slots
...........................

Each slot has a section describing inheritance.  If *note
PyType_Ready(): 77f. may set a value when the field is set to ‘NULL’
then there will also be a “Default” section.  (Note that many fields set
on *note PyBaseObject_Type: 4c37. and *note PyType_Type: 550.
effectively act as defaults.)

 -- C Member: const char **note PyTypeObject: aba.tp_name

     Pointer to a NUL-terminated string containing the name of the type.
     For types that are accessible as module globals, the string should
     be the full module name, followed by a dot, followed by the type
     name; for built-in types, it should be just the type name.  If the
     module is a submodule of a package, the full package name is part
     of the full module name.  For example, a type named ‘T’ defined in
     module ‘M’ in subpackage ‘Q’ in package ‘P’ should have the *note
     tp_name: 1a56. initializer ‘"P.Q.M.T"’.

     For *note dynamically allocated type objects: 96f, this should just
     be the type name, and the module name explicitly stored in the type
     dict as the value for key ‘'__module__'’.

     For *note statically allocated type objects: 782, the 'tp_name'
     field should contain a dot.  Everything before the last dot is made
     accessible as the *note __module__: 377. attribute, and everything
     after the last dot is made accessible as the *note __name__: 14fa.
     attribute.

     If no dot is present, the entire *note tp_name: 1a56. field is made
     accessible as the *note __name__: 14fa. attribute, and the *note
     __module__: 377. attribute is undefined (unless explicitly set in
     the dictionary, as explained above).  This means your type will be
     impossible to pickle.  Additionally, it will not be listed in
     module documentations created with pydoc.

     This field must not be ‘NULL’.  It is the only required field in
     *note PyTypeObject(): aba. (other than potentially *note
     tp_itemsize: 2121.).

     'Inheritance:'

     This field is not inherited by subtypes.

 -- C Member: *note Py_ssize_t: a6e. *note PyTypeObject:
          aba.tp_basicsize
 -- C Member: *note Py_ssize_t: a6e. *note PyTypeObject: aba.tp_itemsize

     These fields allow calculating the size in bytes of instances of
     the type.

     There are two kinds of types: types with fixed-length instances
     have a zero ‘tp_itemsize’ field, types with variable-length
     instances have a non-zero ‘tp_itemsize’ field.  For a type with
     fixed-length instances, all instances have the same size, given in
     ‘tp_basicsize’.  (Exceptions to this rule can be made using *note
     PyUnstable_Object_GC_NewWithExtraData(): 1849.)

     For a type with variable-length instances, the instances must have
     an *note ob_size: 4de3. field, and the instance size is
     ‘tp_basicsize’ plus N times ‘tp_itemsize’, where N is the “length”
     of the object.

     Functions like *note PyObject_NewVar(): 990. will take the value of
     N as an argument, and store in the instance’s *note ob_size: 4de3.
     field.  Note that the ‘ob_size’ field may later be used for other
     purposes.  For example, *note int: 257. instances use the bits of
     ‘ob_size’ in an implementation-defined way; the underlying storage
     and its size should be accessed using ‘PyLong_Export()’.

          Note: The *note ob_size: 4de3. field should be accessed using
          the *note Py_SIZE(): 785. and *note Py_SET_SIZE(): 786.
          macros.

     Also, the presence of an *note ob_size: 4de3. field in the instance
     layout doesn’t mean that the instance structure is variable-length.
     For example, the *note list: 614. type has fixed-length instances,
     yet those instances have a ‘ob_size’ field.  (As with *note int:
     257, avoid reading lists’ ‘ob_size’ directly.  Call *note
     PyList_Size(): 1468. instead.)

     The ‘tp_basicsize’ includes size needed for data of the type’s
     *note tp_base: 20d7, plus any extra data needed by each instance.

     The correct way to set ‘tp_basicsize’ is to use the ‘sizeof’
     operator on the struct used to declare the instance layout.  This
     struct must include the struct used to declare the base type.  In
     other words, ‘tp_basicsize’ must be greater than or equal to the
     base’s ‘tp_basicsize’.

     Since every type is a subtype of *note object: a9b, this struct
     must include *note PyObject: 33a. or *note PyVarObject: 43a6.
     (depending on whether *note ob_size: 4de3. should be included).
     These are usually defined by the macro *note PyObject_HEAD: 1326.
     or *note PyObject_VAR_HEAD: 526d, respectively.

     The basic size does not include the GC header size, as that header
     is not part of *note PyObject_HEAD: 1326.

     For cases where struct used to declare the base type is unknown,
     see *note PyType_Spec.basicsize: 54b. and *note
     PyType_FromMetaclass(): 553.

     Notes about alignment:

        - ‘tp_basicsize’ must be a multiple of ‘_Alignof(PyObject)’.
          When using ‘sizeof’ on a ‘struct’ that includes *note
          PyObject_HEAD: 1326, as recommended, the compiler ensures
          this.  When not using a C ‘struct’, or when using compiler
          extensions like ‘__attribute__((packed))’, it is up to you.

        - If the variable items require a particular alignment,
          ‘tp_basicsize’ and ‘tp_itemsize’ must each be a multiple of
          that alignment.  For example, if a type’s variable part stores
          a ‘double’, it is your responsibility that both fields are a
          multiple of ‘_Alignof(double)’.

     'Inheritance:'

     These fields are inherited separately by subtypes.  (That is, if
     the field is set to zero, *note PyType_Ready(): 77f. will copy the
     value from the base type, indicating that the instances do not need
     additional storage.)

     If the base type has a non-zero *note tp_itemsize: 2121, it is
     generally not safe to set ‘tp_itemsize’ to a different non-zero
     value in a subtype (though this depends on the implementation of
     the base type).

 -- C Member: *note destructor: 4e61. *note PyTypeObject: aba.tp_dealloc

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_dealloc’ is part of
     the *note Stable ABI: 556.'

     A pointer to the instance destructor function.  This function must
     be defined unless the type guarantees that its instances will never
     be deallocated (as is the case for the singletons ‘None’ and
     ‘Ellipsis’).  The function signature is:

          void tp_dealloc(PyObject *self);

     The destructor function is called by the *note Py_DECREF(): 572.
     and *note Py_XDECREF(): 792. macros when the new reference count is
     zero.  At this point, the instance is still in existence, but there
     are no references to it.  The destructor function should free all
     references which the instance owns, free all memory buffers owned
     by the instance (using the freeing function corresponding to the
     allocation function used to allocate the buffer), and call the
     type’s *note tp_free: 4b9a. function.  If the type is not
     subtypable (doesn’t have the *note Py_TPFLAGS_BASETYPE: 4b9f. flag
     bit set), it is permissible to call the object deallocator directly
     instead of via ‘tp_free’.  The object deallocator should be the one
     used to allocate the instance; this is normally *note
     PyObject_Del(): 1520. if the instance was allocated using *note
     PyObject_New: 98f. or *note PyObject_NewVar: 990, or *note
     PyObject_GC_Del(): 1553. if the instance was allocated using *note
     PyObject_GC_New: ab7. or *note PyObject_GC_NewVar: ab8.

     If the type supports garbage collection (has the *note
     Py_TPFLAGS_HAVE_GC: 780. flag bit set), the destructor should call
     *note PyObject_GC_UnTrack(): 1555. before clearing any member
     fields.

          static void foo_dealloc(foo_object *self) {
              PyObject_GC_UnTrack(self);
              Py_CLEAR(self->ref);
              Py_TYPE(self)->tp_free((PyObject *)self);
          }

     Finally, if the type is heap allocated (*note Py_TPFLAGS_HEAPTYPE:
     8b7.), the deallocator should release the owned reference to its
     type object (via *note Py_DECREF(): 572.) after calling the type
     deallocator.  In order to avoid dangling pointers, the recommended
     way to achieve this is:

          static void foo_dealloc(foo_object *self) {
              PyTypeObject *tp = Py_TYPE(self);
              // free references and buffers here
              tp->tp_free(self);
              Py_DECREF(tp);
          }

          Warning: In a garbage collected Python, ‘tp_dealloc’ may be
          called from any Python thread, not just the thread which
          created the object (if the object becomes part of a refcount
          cycle, that cycle might be collected by a garbage collection
          on any thread).  This is not a problem for Python API calls,
          since the thread on which ‘tp_dealloc’ is called will own the
          Global Interpreter Lock (GIL). However, if the object being
          destroyed in turn destroys objects from some other C or C++
          library, care should be taken to ensure that destroying those
          objects on the thread which called ‘tp_dealloc’ will not
          violate any assumptions of the library.

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: *note Py_ssize_t: a6e. *note PyTypeObject:
          aba.tp_vectorcall_offset

     An optional offset to a per-instance function that implements
     calling the object using the *note vectorcall protocol: 555, a more
     efficient alternative of the simpler *note tp_call: 55c.

     This field is only used if the flag *note
     Py_TPFLAGS_HAVE_VECTORCALL: 557. is set.  If so, this must be a
     positive integer containing the offset in the instance of a *note
     vectorcallfunc: 55a. pointer.

     The 'vectorcallfunc' pointer may be ‘NULL’, in which case the
     instance behaves as if *note Py_TPFLAGS_HAVE_VECTORCALL: 557. was
     not set: calling the instance falls back to *note tp_call: 55c.

     Any class that sets ‘Py_TPFLAGS_HAVE_VECTORCALL’ must also set
     *note tp_call: 55c. and make sure its behaviour is consistent with
     the 'vectorcallfunc' function.  This can be done by setting
     'tp_call' to *note PyVectorcall_Call(): 559.

     Changed in version 3.8: Before version 3.8, this slot was named
     ‘tp_print’.  In Python 2.x, it was used for printing to a file.  In
     Python 3.0 to 3.7, it was unused.

     Changed in version 3.12: Before version 3.12, it was not
     recommended for *note mutable heap types: 96f. to implement the
     vectorcall protocol.  When a user sets *note __call__: 55b. in
     Python code, only 'tp_call' is updated, likely making it
     inconsistent with the vectorcall function.  Since 3.12, setting
     ‘__call__’ will disable vectorcall optimization by clearing the
     *note Py_TPFLAGS_HAVE_VECTORCALL: 557. flag.

     'Inheritance:'

     This field is always inherited.  However, the *note
     Py_TPFLAGS_HAVE_VECTORCALL: 557. flag is not always inherited.  If
     it’s not set, then the subclass won’t use *note vectorcall: 555,
     except when *note PyVectorcall_Call(): 559. is explicitly called.

 -- C Member: *note getattrfunc: 4e62. *note PyTypeObject:
          aba.tp_getattr

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_getattr’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to the get-attribute-string function.

     This field is deprecated.  When it is defined, it should point to a
     function that acts the same as the *note tp_getattro: 1803.
     function, but taking a C string instead of a Python string object
     to give the attribute name.

     'Inheritance:'

     Group: *note tp_getattr: 4bb7, *note tp_getattro: 1803.

     This field is inherited by subtypes together with *note
     tp_getattro: 1803.: a subtype inherits both *note tp_getattr: 4bb7.
     and ‘tp_getattro’ from its base type when the subtype’s
     ‘tp_getattr’ and ‘tp_getattro’ are both ‘NULL’.

 -- C Member: *note setattrfunc: 4e72. *note PyTypeObject:
          aba.tp_setattr

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_setattr’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to the function for setting and deleting
     attributes.

     This field is deprecated.  When it is defined, it should point to a
     function that acts the same as the *note tp_setattro: 4bb2.
     function, but taking a C string instead of a Python string object
     to give the attribute name.

     'Inheritance:'

     Group: *note tp_setattr: 4bb8, *note tp_setattro: 4bb2.

     This field is inherited by subtypes together with *note
     tp_setattro: 4bb2.: a subtype inherits both *note tp_setattr: 4bb8.
     and ‘tp_setattro’ from its base type when the subtype’s
     ‘tp_setattr’ and ‘tp_setattro’ are both ‘NULL’.

 -- C Member: *note PyAsyncMethods: 4f9f. **note PyTypeObject:
          aba.tp_as_async

     Pointer to an additional structure that contains fields relevant
     only to objects which implement *note awaitable: 1ad. and *note
     asynchronous iterator: 1ab. protocols at the C-level.  See *note
     Async Object Structures: 52d2. for details.

     Added in version 3.5: Formerly known as ‘tp_compare’ and
     ‘tp_reserved’.

     'Inheritance:'

     The *note tp_as_async: f03. field is not inherited, but the
     contained fields are inherited individually.

 -- C Member: *note reprfunc: 4e70. *note PyTypeObject: aba.tp_repr

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_repr’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a function that implements the built-in
     function *note repr(): 803.

     The signature is the same as for *note PyObject_Repr(): 106c.:

          PyObject *tp_repr(PyObject *self);

     The function must return a string or a Unicode object.  Ideally,
     this function should return a string that, when passed to *note
     eval(): 180, given a suitable environment, returns an object with
     the same value.  If this is not feasible, it should return a string
     starting with ‘'<'’ and ending with ‘'>'’ from which both the type
     and the value of the object can be deduced.

     'Inheritance:'

     This field is inherited by subtypes.

     'Default:'

     When this field is not set, a string of the form ‘<%s object at
     %p>’ is returned, where ‘%s’ is replaced by the type name, and ‘%p’
     by the object’s memory address.

 -- C Member: *note PyNumberMethods: 146c. **note PyTypeObject:
          aba.tp_as_number

     Pointer to an additional structure that contains fields relevant
     only to objects which implement the number protocol.  These fields
     are documented in *note Number Object Structures: 52d3.

     'Inheritance:'

     The *note tp_as_number: 995. field is not inherited, but the
     contained fields are inherited individually.

 -- C Member: *note PySequenceMethods: 4bbe. **note PyTypeObject:
          aba.tp_as_sequence

     Pointer to an additional structure that contains fields relevant
     only to objects which implement the sequence protocol.  These
     fields are documented in *note Sequence Object Structures: 52d4.

     'Inheritance:'

     The *note tp_as_sequence: 5294. field is not inherited, but the
     contained fields are inherited individually.

 -- C Member: *note PyMappingMethods: 4bbf. **note PyTypeObject:
          aba.tp_as_mapping

     Pointer to an additional structure that contains fields relevant
     only to objects which implement the mapping protocol.  These fields
     are documented in *note Mapping Object Structures: 52d5.

     'Inheritance:'

     The *note tp_as_mapping: 5295. field is not inherited, but the
     contained fields are inherited individually.

 -- C Member: *note hashfunc: 4e67. *note PyTypeObject: aba.tp_hash

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_hash’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a function that implements the built-in
     function *note hash(): 5ee.

     The signature is the same as for *note PyObject_Hash(): 406.:

          Py_hash_t tp_hash(PyObject *);

     The value ‘-1’ should not be returned as a normal return value;
     when an error occurs during the computation of the hash value, the
     function should set an exception and return ‘-1’.

     When this field is not set ('and' *note tp_richcompare: 4bba. is
     not set), an attempt to take the hash of the object raises *note
     TypeError: 2c3.  This is the same as setting it to *note
     PyObject_HashNotImplemented(): 1413.

     This field can be set explicitly to *note
     PyObject_HashNotImplemented(): 1413. to block inheritance of the
     hash method from a parent type.  This is interpreted as the
     equivalent of ‘__hash__ = None’ at the Python level, causing
     ‘isinstance(o, collections.Hashable)’ to correctly return ‘False’.
     Note that the converse is also true - setting ‘__hash__ = None’ on
     a class at the Python level will result in the ‘tp_hash’ slot being
     set to ‘PyObject_HashNotImplemented()’.

     'Inheritance:'

     Group: *note tp_hash: 4bc0, *note tp_richcompare: 4bba.

     This field is inherited by subtypes together with *note
     tp_richcompare: 4bba.: a subtype inherits both of ‘tp_richcompare’
     and *note tp_hash: 4bc0, when the subtype’s ‘tp_richcompare’ and
     ‘tp_hash’ are both ‘NULL’.

     'Default:'

     *note PyBaseObject_Type: 4c37. uses *note PyObject_GenericHash():
     36a.

 -- C Member: *note ternaryfunc: 4e77. *note PyTypeObject: aba.tp_call

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_call’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a function that implements calling the
     object.  This should be ‘NULL’ if the object is not callable.  The
     signature is the same as for *note PyObject_Call(): 39f.:

          PyObject *tp_call(PyObject *self, PyObject *args, PyObject *kwargs);

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: *note reprfunc: 4e70. *note PyTypeObject: aba.tp_str

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_str’ is part of the
     *note Stable ABI: 556.'

     An optional pointer to a function that implements the built-in
     operation *note str(): 44f.  (Note that *note str: 44f. is a type
     now, and ‘str()’ calls the constructor for that type.  This
     constructor calls *note PyObject_Str(): 106d. to do the actual
     work, and ‘PyObject_Str()’ will call this handler.)

     The signature is the same as for *note PyObject_Str(): 106d.:

          PyObject *tp_str(PyObject *self);

     The function must return a string or a Unicode object.  It should
     be a “friendly” string representation of the object, as this is the
     representation that will be used, among other things, by the *note
     print(): fae. function.

     'Inheritance:'

     This field is inherited by subtypes.

     'Default:'

     When this field is not set, *note PyObject_Repr(): 106c. is called
     to return a string representation.

 -- C Member: *note getattrofunc: 4e63. *note PyTypeObject:
          aba.tp_getattro

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_getattro’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to the get-attribute function.

     The signature is the same as for *note PyObject_GetAttr(): 34c.:

          PyObject *tp_getattro(PyObject *self, PyObject *attr);

     It is usually convenient to set this field to *note
     PyObject_GenericGetAttr(): 4d54, which implements the normal way of
     looking for object attributes.

     'Inheritance:'

     Group: *note tp_getattr: 4bb7, *note tp_getattro: 1803.

     This field is inherited by subtypes together with *note tp_getattr:
     4bb7.: a subtype inherits both ‘tp_getattr’ and *note tp_getattro:
     1803. from its base type when the subtype’s ‘tp_getattr’ and
     ‘tp_getattro’ are both ‘NULL’.

     'Default:'

     *note PyBaseObject_Type: 4c37. uses *note
     PyObject_GenericGetAttr(): 4d54.

 -- C Member: *note setattrofunc: 4e73. *note PyTypeObject:
          aba.tp_setattro

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_setattro’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to the function for setting and deleting
     attributes.

     The signature is the same as for *note PyObject_SetAttr(): 4d5d.:

          int tp_setattro(PyObject *self, PyObject *attr, PyObject *value);

     In addition, setting 'value' to ‘NULL’ to delete an attribute must
     be supported.  It is usually convenient to set this field to *note
     PyObject_GenericSetAttr(): 4d55, which implements the normal way of
     setting object attributes.

     'Inheritance:'

     Group: *note tp_setattr: 4bb8, *note tp_setattro: 4bb2.

     This field is inherited by subtypes together with *note tp_setattr:
     4bb8.: a subtype inherits both ‘tp_setattr’ and *note tp_setattro:
     4bb2. from its base type when the subtype’s ‘tp_setattr’ and
     ‘tp_setattro’ are both ‘NULL’.

     'Default:'

     *note PyBaseObject_Type: 4c37. uses *note
     PyObject_GenericSetAttr(): 4d55.

 -- C Member: *note PyBufferProcs: 4fa7. **note PyTypeObject:
          aba.tp_as_buffer

     Pointer to an additional structure that contains fields relevant
     only to objects which implement the buffer interface.  These fields
     are documented in *note Buffer Object Structures: 4f6b.

     'Inheritance:'

     The *note tp_as_buffer: 993. field is not inherited, but the
     contained fields are inherited individually.

 -- C Member: unsigned long *note PyTypeObject: aba.tp_flags

     This field is a bit mask of various flags.  Some flags indicate
     variant semantics for certain situations; others are used to
     indicate that certain fields in the type object (or in the
     extension structures referenced via *note tp_as_number: 995, *note
     tp_as_sequence: 5294, *note tp_as_mapping: 5295, and *note
     tp_as_buffer: 993.) that were historically not always present are
     valid; if such a flag bit is clear, the type fields it guards must
     not be accessed and must be considered to have a zero or ‘NULL’
     value instead.

     'Inheritance:'

     Inheritance of this field is complicated.  Most flag bits are
     inherited individually, i.e.  if the base type has a flag bit set,
     the subtype inherits this flag bit.  The flag bits that pertain to
     extension structures are strictly inherited if the extension
     structure is inherited, i.e.  the base type’s value of the flag bit
     is copied into the subtype together with a pointer to the extension
     structure.  The *note Py_TPFLAGS_HAVE_GC: 780. flag bit is
     inherited together with the *note tp_traverse: 781. and *note
     tp_clear: 4bac. fields, i.e.  if the ‘Py_TPFLAGS_HAVE_GC’ flag bit
     is clear in the subtype and the ‘tp_traverse’ and ‘tp_clear’ fields
     in the subtype exist and have ‘NULL’ values.  ..  XXX are most flag
     bits 'really' inherited individually?

     'Default:'

     *note PyBaseObject_Type: 4c37. uses ‘Py_TPFLAGS_DEFAULT |
     Py_TPFLAGS_BASETYPE’.

     'Bit Masks:'

     The following bit masks are currently defined; these can be ORed
     together using the ‘|’ operator to form the value of the *note
     tp_flags: 1a18. field.  The macro *note PyType_HasFeature(): 1ae3.
     takes a type and a flags value, 'tp' and 'f', and checks whether
     ‘tp->tp_flags & f’ is non-zero.

      -- C Macro: Py_TPFLAGS_HEAPTYPE

          This bit is set when the type object itself is allocated on
          the heap, for example, types created dynamically using *note
          PyType_FromSpec(): 580.  In this case, the *note ob_type:
          4b98. field of its instances is considered a reference to the
          type, and the type object is INCREF’ed when a new instance is
          created, and DECREF’ed when an instance is destroyed (this
          does not apply to instances of subtypes; only the type
          referenced by the instance’s ob_type gets INCREF’ed or
          DECREF’ed).  Heap types should also *note support garbage
          collection: 52d6. as they can form a reference cycle with
          their own module object.

          'Inheritance:'

          ???

      -- C Macro: Py_TPFLAGS_BASETYPE
          ' Part of the *note Stable ABI: 556.'  This bit is set when
          the type can be used as the base type of another type.  If
          this bit is clear, the type cannot be subtyped (similar to a
          “final” class in Java).

          'Inheritance:'

          ???

      -- C Macro: Py_TPFLAGS_READY

          This bit is set when the type object has been fully
          initialized by *note PyType_Ready(): 77f.

          'Inheritance:'

          ???

      -- C Macro: Py_TPFLAGS_READYING

          This bit is set while *note PyType_Ready(): 77f. is in the
          process of initializing the type object.

          'Inheritance:'

          ???

      -- C Macro: Py_TPFLAGS_HAVE_GC
          ' Part of the *note Stable ABI: 556.'  This bit is set when
          the object supports garbage collection.  If this bit is set,
          instances must be created using *note PyObject_GC_New: ab7.
          and destroyed using *note PyObject_GC_Del(): 1553.  More
          information in section *note Supporting Cyclic Garbage
          Collection: 52d6.  This bit also implies that the GC-related
          fields *note tp_traverse: 781. and *note tp_clear: 4bac. are
          present in the type object.

          'Inheritance:'

          Group: *note Py_TPFLAGS_HAVE_GC: 780, *note tp_traverse: 781,
          *note tp_clear: 4bac.

          The *note Py_TPFLAGS_HAVE_GC: 780. flag bit is inherited
          together with the *note tp_traverse: 781. and *note tp_clear:
          4bac. fields, i.e.  if the ‘Py_TPFLAGS_HAVE_GC’ flag bit is
          clear in the subtype and the ‘tp_traverse’ and ‘tp_clear’
          fields in the subtype exist and have ‘NULL’ values.

      -- C Macro: Py_TPFLAGS_DEFAULT
          ' Part of the *note Stable ABI: 556.'  This is a bitmask of
          all the bits that pertain to the existence of certain fields
          in the type object and its extension structures.  Currently,
          it includes the following bits: *note
          Py_TPFLAGS_HAVE_STACKLESS_EXTENSION: 52d9.

          'Inheritance:'

          ???

      -- C Macro: Py_TPFLAGS_METHOD_DESCRIPTOR
          ' Part of the *note Stable ABI: 556. since version 3.8.'  This
          bit indicates that objects behave like unbound methods.

          If this flag is set for ‘type(meth)’, then:

             - ‘meth.__get__(obj, cls)(*args, **kwds)’ (with ‘obj’ not
               None) must be equivalent to ‘meth(obj, *args, **kwds)’.

             - ‘meth.__get__(None, cls)(*args, **kwds)’ must be
               equivalent to ‘meth(*args, **kwds)’.

          This flag enables an optimization for typical method calls
          like ‘obj.meth()’: it avoids creating a temporary “bound
          method” object for ‘obj.meth’.

          Added in version 3.8.

          'Inheritance:'

          This flag is never inherited by types without the *note
          Py_TPFLAGS_IMMUTABLETYPE: 3c5. flag set.  For extension types,
          it is inherited whenever *note tp_descr_get: 5296. is
          inherited.

      -- C Macro: Py_TPFLAGS_MANAGED_DICT

          This bit indicates that instances of the class have a *note
          __dict__: 55e. attribute, and that the space for the
          dictionary is managed by the VM.

          If this flag is set, *note Py_TPFLAGS_HAVE_GC: 780. should
          also be set.

          The type traverse function must call *note
          PyObject_VisitManagedDict(): 36c. and its clear function must
          call *note PyObject_ClearManagedDict(): 36d.

          Added in version 3.12.

          'Inheritance:'

          This flag is inherited unless the *note tp_dictoffset: 4fa1.
          field is set in a superclass.

      -- C Macro: Py_TPFLAGS_MANAGED_WEAKREF

          This bit indicates that instances of the class should be
          weakly referenceable.

          Added in version 3.12.

          'Inheritance:'

          This flag is inherited unless the *note tp_weaklistoffset:
          992. field is set in a superclass.

      -- C Macro: Py_TPFLAGS_ITEMS_AT_END
          ' Part of the *note Stable ABI: 556. since version 3.12.'
          Only usable with variable-size types, i.e.  ones with non-zero
          *note tp_itemsize: 2121.

          Indicates that the variable-sized portion of an instance of
          this type is at the end of the instance’s memory area, at an
          offset of ‘Py_TYPE(obj)->tp_basicsize’ (which may be different
          in each subclass).

          When setting this flag, be sure that all superclasses either
          use this memory layout, or are not variable-sized.  Python
          does not check this.

          Added in version 3.12.

          'Inheritance:'

          This flag is inherited.

      -- C Macro: Py_TPFLAGS_LONG_SUBCLASS

      -- C Macro: Py_TPFLAGS_LIST_SUBCLASS

      -- C Macro: Py_TPFLAGS_TUPLE_SUBCLASS

      -- C Macro: Py_TPFLAGS_BYTES_SUBCLASS

      -- C Macro: Py_TPFLAGS_UNICODE_SUBCLASS

      -- C Macro: Py_TPFLAGS_DICT_SUBCLASS

      -- C Macro: Py_TPFLAGS_BASE_EXC_SUBCLASS

      -- C Macro: Py_TPFLAGS_TYPE_SUBCLASS

          Functions such as *note PyLong_Check(): 4fb2. will call *note
          PyType_FastSubclass(): 4f92. with one of these flags to
          quickly determine if a type is a subclass of a built-in type;
          such specific checks are faster than a generic check, like
          *note PyObject_IsInstance(): eda.  Custom types that inherit
          from built-ins should have their *note tp_flags: 1a18. set
          appropriately, or the code that interacts with such types will
          behave differently depending on what kind of check is used.

      -- C Macro: Py_TPFLAGS_HAVE_FINALIZE

          This bit is set when the *note tp_finalize: abb. slot is
          present in the type structure.

          Added in version 3.4.

          Deprecated since version 3.8: This flag isn’t necessary
          anymore, as the interpreter assumes the *note tp_finalize:
          abb. slot is always present in the type structure.

      -- C Macro: Py_TPFLAGS_HAVE_VECTORCALL
          ' Part of the *note Stable ABI: 556. since version 3.12.'
          This bit is set when the class implements the *note vectorcall
          protocol: 555.  See *note tp_vectorcall_offset: 4f46. for
          details.

          'Inheritance:'

          This bit is inherited if *note tp_call: 55c. is also
          inherited.

          Added in version 3.8: as ‘_Py_TPFLAGS_HAVE_VECTORCALL’

          Changed in version 3.9.

          Renamed to the current name, without the leading underscore.
          The old provisional name is *note soft deprecated: 209.

          Changed in version 3.12: This flag is now removed from a class
          when the class’s *note __call__(): 55b. method is reassigned.

          This flag can now be inherited by mutable classes.

      -- C Macro: Py_TPFLAGS_IMMUTABLETYPE

          This bit is set for type objects that are immutable: type
          attributes cannot be set nor deleted.

          *note PyType_Ready(): 77f. automatically applies this flag to
          *note static types: 782.

          'Inheritance:'

          This flag is not inherited.

          Added in version 3.10.

      -- C Macro: Py_TPFLAGS_DISALLOW_INSTANTIATION

          Disallow creating instances of the type: set *note tp_new:
          582. to NULL and don’t create the ‘__new__’ key in the type
          dictionary.

          The flag must be set before creating the type, not after.  For
          example, it must be set before *note PyType_Ready(): 77f. is
          called on the type.

          The flag is set automatically on *note static types: 782. if
          *note tp_base: 20d7. is NULL or ‘&PyBaseObject_Type’ and *note
          tp_new: 582. is NULL.

          'Inheritance:'

          This flag is not inherited.  However, subclasses will not be
          instantiable unless they provide a non-NULL *note tp_new: 582.
          (which is only possible via the C API).

               Note: To disallow instantiating a class directly but
               allow instantiating its subclasses (e.g.  for an *note
               abstract base class: 11fa.), do not use this flag.
               Instead, make *note tp_new: 582. only succeed for
               subclasses.

          Added in version 3.10.

      -- C Macro: Py_TPFLAGS_MAPPING

          This bit indicates that instances of the class may match
          mapping patterns when used as the subject of a *note match:
          813. block.  It is automatically set when registering or
          subclassing *note collections.abc.Mapping: 8d3, and unset when
          registering *note collections.abc.Sequence: 1209.

               Note: *note Py_TPFLAGS_MAPPING: 19fe. and *note
               Py_TPFLAGS_SEQUENCE: 19ff. are mutually exclusive; it is
               an error to enable both flags simultaneously.

          'Inheritance:'

          This flag is inherited by types that do not already set *note
          Py_TPFLAGS_SEQUENCE: 19ff.

          See also
          ........

          PEP 634(1) – Structural Pattern Matching: Specification

          Added in version 3.10.

      -- C Macro: Py_TPFLAGS_SEQUENCE

          This bit indicates that instances of the class may match
          sequence patterns when used as the subject of a *note match:
          813. block.  It is automatically set when registering or
          subclassing *note collections.abc.Sequence: 1209, and unset
          when registering *note collections.abc.Mapping: 8d3.

               Note: *note Py_TPFLAGS_MAPPING: 19fe. and *note
               Py_TPFLAGS_SEQUENCE: 19ff. are mutually exclusive; it is
               an error to enable both flags simultaneously.

          'Inheritance:'

          This flag is inherited by types that do not already set *note
          Py_TPFLAGS_MAPPING: 19fe.

          See also
          ........

          PEP 634(2) – Structural Pattern Matching: Specification

          Added in version 3.10.

      -- C Macro: Py_TPFLAGS_VALID_VERSION_TAG

          Internal.  Do not set or unset this flag.  To indicate that a
          class has changed call *note PyType_Modified(): 1921.

               Warning: This flag is present in header files, but is not
               be used.  It will be removed in a future version of
               CPython

      -- C Macro: Py_TPFLAGS_HAVE_VERSION_TAG

          This is a *note soft deprecated: 209. macro that does nothing.
          Historically, this would indicate that the *note
          tp_version_tag: 529a. field was available and initialized.

      -- C Macro: Py_TPFLAGS_INLINE_VALUES

          This bit indicates that instances of this type will have an
          “inline values” array (containing the object’s attributes)
          placed directly after the end of the object.

          This requires that *note Py_TPFLAGS_HAVE_GC: 780. is set.

          'Inheritance:'

          This flag is not inherited.

          Added in version 3.13.

      -- C Macro: Py_TPFLAGS_IS_ABSTRACT

          This bit indicates that this is an abstract type and therefore
          cannot be instantiated.

          'Inheritance:'

          This flag is not inherited.

          See also
          ........

          *note abc: 4.

      -- C Macro: Py_TPFLAGS_HAVE_STACKLESS_EXTENSION

          Internal.  Do not set or unset this flag.  Historically, this
          was a reserved flag for use in Stackless Python.

               Warning: This flag is present in header files, but is not
               be used.  This may be removed in a future version of
               CPython.

 -- C Member: const char **note PyTypeObject: aba.tp_doc

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_doc’ is part of the
     *note Stable ABI: 556.'

     An optional pointer to a NUL-terminated C string giving the
     docstring for this type object.  This is exposed as the *note
     __doc__: 1e4d. attribute on the type and instances of the type.

     'Inheritance:'

     This field is 'not' inherited by subtypes.

 -- C Member: *note traverseproc: 4e78. *note PyTypeObject:
          aba.tp_traverse

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_traverse’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to a traversal function for the garbage
     collector.  This is only used if the *note Py_TPFLAGS_HAVE_GC: 780.
     flag bit is set.  The signature is:

          int tp_traverse(PyObject *self, visitproc visit, void *arg);

     More information about Python’s garbage collection scheme can be
     found in section *note Supporting Cyclic Garbage Collection: 52d6.

     The *note tp_traverse: 781. pointer is used by the garbage
     collector to detect reference cycles.  A typical implementation of
     a ‘tp_traverse’ function simply calls *note Py_VISIT(): 4ba3. on
     each of the instance’s members that are Python objects that the
     instance owns.  For example, this is function ‘local_traverse()’
     from the ‘_thread’ extension module:

          static int
          local_traverse(localobject *self, visitproc visit, void *arg)
          {
              Py_VISIT(self->args);
              Py_VISIT(self->kw);
              Py_VISIT(self->dict);
              return 0;
          }

     Note that *note Py_VISIT(): 4ba3. is called only on those members
     that can participate in reference cycles.  Although there is also a
     ‘self->key’ member, it can only be ‘NULL’ or a Python string and
     therefore cannot be part of a reference cycle.

     On the other hand, even if you know a member can never be part of a
     cycle, as a debugging aid you may want to visit it anyway just so
     the *note gc: 60. module’s *note get_referents(): 80b. function
     will include it.

     Heap types (*note Py_TPFLAGS_HEAPTYPE: 8b7.) must visit their type
     with:

          Py_VISIT(Py_TYPE(self));

     It is only needed since Python 3.9.  To support Python 3.8 and
     older, this line must be conditional:

          #if PY_VERSION_HEX >= 0x03090000
              Py_VISIT(Py_TYPE(self));
          #endif

     If the *note Py_TPFLAGS_MANAGED_DICT: 36e. bit is set in the *note
     tp_flags: 1a18. field, the traverse function must call *note
     PyObject_VisitManagedDict(): 36c. like this:

          PyObject_VisitManagedDict((PyObject*)self, visit, arg);

          Warning: When implementing *note tp_traverse: 781, only the
          members that the instance 'owns' (by having *note strong
          references: 33e. to them) must be visited.  For instance, if
          an object supports weak references via the *note tp_weaklist:
          4fa6. slot, the pointer supporting the linked list (what
          'tp_weaklist' points to) must 'not' be visited as the instance
          does not directly own the weak references to itself (the
          weakreference list is there to support the weak reference
          machinery, but the instance has no strong reference to the
          elements inside it, as they are allowed to be removed even if
          the instance is still alive).

          Warning: The traversal function must not have any side
          effects.  It must not modify the reference counts of any
          Python objects nor create or destroy any Python objects.

     Note that *note Py_VISIT(): 4ba3. requires the 'visit' and 'arg'
     parameters to ‘local_traverse()’ to have these specific names;
     don’t name them just anything.

     Instances of *note heap-allocated types: 96f. hold a reference to
     their type.  Their traversal function must therefore either visit
     *note Py_TYPE(self): 783, or delegate this responsibility by
     calling ‘tp_traverse’ of another heap-allocated type (such as a
     heap-allocated superclass).  If they do not, the type object may
     not be garbage-collected.

     Changed in version 3.9: Heap-allocated types are expected to visit
     ‘Py_TYPE(self)’ in ‘tp_traverse’.  In earlier versions of Python,
     due to bug 40217(3), doing this may lead to crashes in subclasses.

     'Inheritance:'

     Group: *note Py_TPFLAGS_HAVE_GC: 780, *note tp_traverse: 781, *note
     tp_clear: 4bac.

     This field is inherited by subtypes together with *note tp_clear:
     4bac. and the *note Py_TPFLAGS_HAVE_GC: 780. flag bit: the flag
     bit, *note tp_traverse: 781, and ‘tp_clear’ are all inherited from
     the base type if they are all zero in the subtype.

 -- C Member: *note inquiry: 4e69. *note PyTypeObject: aba.tp_clear

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_clear’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a clear function for the garbage collector.
     This is only used if the *note Py_TPFLAGS_HAVE_GC: 780. flag bit is
     set.  The signature is:

          int tp_clear(PyObject *);

     The *note tp_clear: 4bac. member function is used to break
     reference cycles in cyclic garbage detected by the garbage
     collector.  Taken together, all ‘tp_clear’ functions in the system
     must combine to break all reference cycles.  This is subtle, and if
     in any doubt supply a ‘tp_clear’ function.  For example, the tuple
     type does not implement a ‘tp_clear’ function, because it’s
     possible to prove that no reference cycle can be composed entirely
     of tuples.  Therefore the ‘tp_clear’ functions of other types must
     be sufficient to break any cycle containing a tuple.  This isn’t
     immediately obvious, and there’s rarely a good reason to avoid
     implementing ‘tp_clear’.

     Implementations of *note tp_clear: 4bac. should drop the instance’s
     references to those of its members that may be Python objects, and
     set its pointers to those members to ‘NULL’, as in the following
     example:

          static int
          local_clear(localobject *self)
          {
              Py_CLEAR(self->key);
              Py_CLEAR(self->args);
              Py_CLEAR(self->kw);
              Py_CLEAR(self->dict);
              return 0;
          }

     The *note Py_CLEAR(): 57b. macro should be used, because clearing
     references is delicate: the reference to the contained object must
     not be released (via *note Py_DECREF(): 572.) until after the
     pointer to the contained object is set to ‘NULL’.  This is because
     releasing the reference may cause the contained object to become
     trash, triggering a chain of reclamation activity that may include
     invoking arbitrary Python code (due to finalizers, or weakref
     callbacks, associated with the contained object).  If it’s possible
     for such code to reference 'self' again, it’s important that the
     pointer to the contained object be ‘NULL’ at that time, so that
     'self' knows the contained object can no longer be used.  The
     ‘Py_CLEAR()’ macro performs the operations in a safe order.

     If the *note Py_TPFLAGS_MANAGED_DICT: 36e. bit is set in the *note
     tp_flags: 1a18. field, the clear function must call *note
     PyObject_ClearManagedDict(): 36d. like this:

          PyObject_ClearManagedDict((PyObject*)self);

     Note that *note tp_clear: 4bac. is not 'always' called before an
     instance is deallocated.  For example, when reference counting is
     enough to determine that an object is no longer used, the cyclic
     garbage collector is not involved and *note tp_dealloc: 4b87. is
     called directly.

     Because the goal of *note tp_clear: 4bac. functions is to break
     reference cycles, it’s not necessary to clear contained objects
     like Python strings or Python integers, which can’t participate in
     reference cycles.  On the other hand, it may be convenient to clear
     all contained Python objects, and write the type’s *note
     tp_dealloc: 4b87. function to invoke ‘tp_clear’.

     More information about Python’s garbage collection scheme can be
     found in section *note Supporting Cyclic Garbage Collection: 52d6.

     'Inheritance:'

     Group: *note Py_TPFLAGS_HAVE_GC: 780, *note tp_traverse: 781, *note
     tp_clear: 4bac.

     This field is inherited by subtypes together with *note
     tp_traverse: 781. and the *note Py_TPFLAGS_HAVE_GC: 780. flag bit:
     the flag bit, ‘tp_traverse’, and *note tp_clear: 4bac. are all
     inherited from the base type if they are all zero in the subtype.

 -- C Member: *note richcmpfunc: 4e71. *note PyTypeObject:
          aba.tp_richcompare

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_richcompare’ is
     part of the *note Stable ABI: 556.'

     An optional pointer to the rich comparison function, whose
     signature is:

          PyObject *tp_richcompare(PyObject *self, PyObject *other, int op);

     The first parameter is guaranteed to be an instance of the type
     that is defined by *note PyTypeObject: aba.

     The function should return the result of the comparison (usually
     ‘Py_True’ or ‘Py_False’).  If the comparison is undefined, it must
     return ‘Py_NotImplemented’, if another error occurred it must
     return ‘NULL’ and set an exception condition.

     The following constants are defined to be used as the third
     argument for *note tp_richcompare: 4bba. and for *note
     PyObject_RichCompare(): 4bbb.:

     Constant                 Comparison
                              
     ------------------------------------------
                              
      -- C Macro: Py_LT       ‘<’
                              
                              
      -- C Macro: Py_LE       ‘<=’
                              
                              
      -- C Macro: Py_EQ       ‘==’
                              
                              
      -- C Macro: Py_NE       ‘!=’
                              
                              
      -- C Macro: Py_GT       ‘>’
                              
                              
      -- C Macro: Py_GE       ‘>=’
                              

     The following macro is defined to ease writing rich comparison
     functions:

      -- C Macro: Py_RETURN_RICHCOMPARE (VAL_A, VAL_B, op)

          Return ‘Py_True’ or ‘Py_False’ from the function, depending on
          the result of a comparison.  VAL_A and VAL_B must be orderable
          by C comparison operators (for example, they may be C ints or
          floats).  The third argument specifies the requested
          operation, as for *note PyObject_RichCompare(): 4bbb.

          The returned value is a new *note strong reference: 33e.

          On error, sets an exception and returns ‘NULL’ from the
          function.

          Added in version 3.7.

     'Inheritance:'

     Group: *note tp_hash: 4bc0, *note tp_richcompare: 4bba.

     This field is inherited by subtypes together with *note tp_hash:
     4bc0.: a subtype inherits *note tp_richcompare: 4bba. and ‘tp_hash’
     when the subtype’s ‘tp_richcompare’ and ‘tp_hash’ are both ‘NULL’.

     'Default:'

     *note PyBaseObject_Type: 4c37. provides a *note tp_richcompare:
     4bba. implementation, which may be inherited.  However, if only
     *note tp_hash: 4bc0. is defined, not even the inherited function is
     used and instances of the type will not be able to participate in
     any comparisons.

 -- C Member: *note Py_ssize_t: a6e. *note PyTypeObject:
          aba.tp_weaklistoffset

     While this field is still supported, *note
     Py_TPFLAGS_MANAGED_WEAKREF: 55d. should be used instead, if at all
     possible.

     If the instances of this type are weakly referenceable, this field
     is greater than zero and contains the offset in the instance
     structure of the weak reference list head (ignoring the GC header,
     if present); this offset is used by *note PyObject_ClearWeakRefs():
     579. and the ‘PyWeakref_*’ functions.  The instance structure needs
     to include a field of type *note PyObject: 33a.* which is
     initialized to ‘NULL’.

     Do not confuse this field with *note tp_weaklist: 4fa6.; that is
     the list head for weak references to the type object itself.

     It is an error to set both the *note Py_TPFLAGS_MANAGED_WEAKREF:
     55d. bit and *note tp_weaklistoffset: 992.

     'Inheritance:'

     This field is inherited by subtypes, but see the rules listed
     below.  A subtype may override this offset; this means that the
     subtype uses a different weak reference list head than the base
     type.  Since the list head is always found via *note
     tp_weaklistoffset: 992, this should not be a problem.

     'Default:'

     If the *note Py_TPFLAGS_MANAGED_WEAKREF: 55d. bit is set in the
     *note tp_flags: 1a18. field, then *note tp_weaklistoffset: 992.
     will be set to a negative value, to indicate that it is unsafe to
     use this field.

 -- C Member: *note getiterfunc: 4e65. *note PyTypeObject: aba.tp_iter

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_iter’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a function that returns an *note iterator:
     1ac. for the object.  Its presence normally signals that the
     instances of this type are *note iterable: 126d. (although
     sequences may be iterable without this function).

     This function has the same signature as *note PyObject_GetIter():
     4d58.:

          PyObject *tp_iter(PyObject *self);

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: *note iternextfunc: 4e6a. *note PyTypeObject:
          aba.tp_iternext

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_iternext’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to a function that returns the next item in an
     *note iterator: 1ac.  The signature is:

          PyObject *tp_iternext(PyObject *self);

     When the iterator is exhausted, it must return ‘NULL’; a *note
     StopIteration: c1b. exception may or may not be set.  When another
     error occurs, it must return ‘NULL’ too.  Its presence signals that
     the instances of this type are iterators.

     Iterator types should also define the *note tp_iter: 153e.
     function, and that function should return the iterator instance
     itself (not a new iterator instance).

     This function has the same signature as *note PyIter_Next(): 4cff.

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: struct *note PyMethodDef: 1526. **note PyTypeObject:
          aba.tp_methods

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_methods’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a static ‘NULL’-terminated array of *note
     PyMethodDef: 1526. structures, declaring regular methods of this
     type.

     For each entry in the array, an entry is added to the type’s
     dictionary (see *note tp_dict: 182b. below) containing a method
     descriptor.

     'Inheritance:'

     This field is not inherited by subtypes (methods are inherited
     through a different mechanism).

 -- C Member: struct *note PyMemberDef: 552. **note PyTypeObject:
          aba.tp_members

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_members’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a static ‘NULL’-terminated array of *note
     PyMemberDef: 552. structures, declaring regular data members
     (fields or slots) of instances of this type.

     For each entry in the array, an entry is added to the type’s
     dictionary (see *note tp_dict: 182b. below) containing a member
     descriptor.

     'Inheritance:'

     This field is not inherited by subtypes (members are inherited
     through a different mechanism).

 -- C Member: struct *note PyGetSetDef: bd7. **note PyTypeObject:
          aba.tp_getset

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_getset’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a static ‘NULL’-terminated array of *note
     PyGetSetDef: bd7. structures, declaring computed attributes of
     instances of this type.

     For each entry in the array, an entry is added to the type’s
     dictionary (see *note tp_dict: 182b. below) containing a getset
     descriptor.

     'Inheritance:'

     This field is not inherited by subtypes (computed attributes are
     inherited through a different mechanism).

 -- C Member: *note PyTypeObject: aba. **note PyTypeObject: aba.tp_base

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_base’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a base type from which type properties are
     inherited.  At this level, only single inheritance is supported;
     multiple inheritance require dynamically creating a type object by
     calling the metatype.

          Note: 
          Slot initialization is subject to the rules of initializing
          globals.  C99 requires the initializers to be “address
          constants”.  Function designators like *note
          PyType_GenericNew(): 4b97, with implicit conversion to a
          pointer, are valid C99 address constants.

          However, the unary ‘&’ operator applied to a non-static
          variable like *note PyBaseObject_Type: 4c37. is not required
          to produce an address constant.  Compilers may support this
          (gcc does), MSVC does not.  Both compilers are strictly
          standard conforming in this particular behavior.

          Consequently, *note tp_base: 20d7. should be set in the
          extension module’s init function.

     'Inheritance:'

     This field is not inherited by subtypes (obviously).

     'Default:'

     This field defaults to ‘&PyBaseObject_Type’ (which to Python
     programmers is known as the type *note object: a9b.).

 -- C Member: *note PyObject: 33a. **note PyTypeObject: aba.tp_dict

     The type’s dictionary is stored here by *note PyType_Ready(): 77f.

     This field should normally be initialized to ‘NULL’ before
     PyType_Ready is called; it may also be initialized to a dictionary
     containing initial attributes for the type.  Once *note
     PyType_Ready(): 77f. has initialized the type, extra attributes for
     the type may be added to this dictionary only if they don’t
     correspond to overloaded operations (like *note __add__(): 2145.).
     Once initialization for the type has finished, this field should be
     treated as read-only.

     Some types may not store their dictionary in this slot.  Use *note
     PyType_GetDict(): 182a. to retrieve the dictionary for an arbitrary
     type.

     Changed in version 3.12: Internals detail: For static builtin
     types, this is always ‘NULL’.  Instead, the dict for such types is
     stored on ‘PyInterpreterState’.  Use *note PyType_GetDict(): 182a.
     to get the dict for an arbitrary type.

     'Inheritance:'

     This field is not inherited by subtypes (though the attributes
     defined in here are inherited through a different mechanism).

     'Default:'

     If this field is ‘NULL’, *note PyType_Ready(): 77f. will assign a
     new dictionary to it.

          Warning: It is not safe to use *note PyDict_SetItem(): 4b84.
          on or otherwise modify *note tp_dict: 182b. with the
          dictionary C-API.

 -- C Member: *note descrgetfunc: 4e5f. *note PyTypeObject:
          aba.tp_descr_get

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_descr_get’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to a “descriptor get” function.

     The function signature is:

          PyObject * tp_descr_get(PyObject *self, PyObject *obj, PyObject *type);

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: *note descrsetfunc: 4e60. *note PyTypeObject:
          aba.tp_descr_set

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_descr_set’ is part
     of the *note Stable ABI: 556.'

     An optional pointer to a function for setting and deleting a
     descriptor’s value.

     The function signature is:

          int tp_descr_set(PyObject *self, PyObject *obj, PyObject *value);

     The 'value' argument is set to ‘NULL’ to delete the value.

     'Inheritance:'

     This field is inherited by subtypes.

 -- C Member: *note Py_ssize_t: a6e. *note PyTypeObject:
          aba.tp_dictoffset

     While this field is still supported, *note Py_TPFLAGS_MANAGED_DICT:
     36e. should be used instead, if at all possible.

     If the instances of this type have a dictionary containing instance
     variables, this field is non-zero and contains the offset in the
     instances of the type of the instance variable dictionary; this
     offset is used by *note PyObject_GenericGetAttr(): 4d54.

     Do not confuse this field with *note tp_dict: 182b.; that is the
     dictionary for attributes of the type object itself.

     The value specifies the offset of the dictionary from the start of
     the instance structure.

     The *note tp_dictoffset: 4fa1. should be regarded as write-only.
     To get the pointer to the dictionary call *note
     PyObject_GenericGetDict(): 1aac.  Calling
     ‘PyObject_GenericGetDict()’ may need to allocate memory for the
     dictionary, so it is may be more efficient to call *note
     PyObject_GetAttr(): 34c. when accessing an attribute on the object.

     It is an error to set both the *note Py_TPFLAGS_MANAGED_DICT: 36e.
     bit and *note tp_dictoffset: 4fa1.

     'Inheritance:'

     This field is inherited by subtypes.  A subtype should not override
     this offset; doing so could be unsafe, if C code tries to access
     the dictionary at the previous offset.  To properly support
     inheritance, use *note Py_TPFLAGS_MANAGED_DICT: 36e.

     'Default:'

     This slot has no default.  For *note static types: 782, if the
     field is ‘NULL’ then no *note __dict__: 55e. gets created for
     instances.

     If the *note Py_TPFLAGS_MANAGED_DICT: 36e. bit is set in the *note
     tp_flags: 1a18. field, then *note tp_dictoffset: 4fa1. will be set
     to ‘-1’, to indicate that it is unsafe to use this field.

 -- C Member: *note initproc: 4e68. *note PyTypeObject: aba.tp_init

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_init’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to an instance initialization function.

     This function corresponds to the *note __init__(): 6b3. method of
     classes.  Like ‘__init__()’, it is possible to create an instance
     without calling ‘__init__()’, and it is possible to reinitialize an
     instance by calling its ‘__init__()’ method again.

     The function signature is:

          int tp_init(PyObject *self, PyObject *args, PyObject *kwds);

     The self argument is the instance to be initialized; the 'args' and
     'kwds' arguments represent positional and keyword arguments of the
     call to *note __init__(): 6b3.

     The *note tp_init: 584. function, if not ‘NULL’, is called when an
     instance is created normally by calling its type, after the type’s
     *note tp_new: 582. function has returned an instance of the type.
     If the ‘tp_new’ function returns an instance of some other type
     that is not a subtype of the original type, no ‘tp_init’ function
     is called; if ‘tp_new’ returns an instance of a subtype of the
     original type, the subtype’s ‘tp_init’ is called.

     Returns ‘0’ on success, ‘-1’ and sets an exception on error.

     'Inheritance:'

     This field is inherited by subtypes.

     'Default:'

     For *note static types: 782. this field does not have a default.

 -- C Member: *note allocfunc: 4e5d. *note PyTypeObject: aba.tp_alloc

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_alloc’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to an instance allocation function.

     The function signature is:

          PyObject *tp_alloc(PyTypeObject *self, Py_ssize_t nitems);

     'Inheritance:'

     This field is inherited by static subtypes, but not by dynamic
     subtypes (subtypes created by a class statement).

     'Default:'

     For dynamic subtypes, this field is always set to *note
     PyType_GenericAlloc(): a7a, to force a standard heap allocation
     strategy.

     For static subtypes, *note PyBaseObject_Type: 4c37. uses *note
     PyType_GenericAlloc(): a7a.  That is the recommended value for all
     statically defined types.

 -- C Member: *note newfunc: 4e6c. *note PyTypeObject: aba.tp_new

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_new’ is part of the
     *note Stable ABI: 556.'

     An optional pointer to an instance creation function.

     The function signature is:

          PyObject *tp_new(PyTypeObject *subtype, PyObject *args, PyObject *kwds);

     The 'subtype' argument is the type of the object being created; the
     'args' and 'kwds' arguments represent positional and keyword
     arguments of the call to the type.  Note that 'subtype' doesn’t
     have to equal the type whose *note tp_new: 582. function is called;
     it may be a subtype of that type (but not an unrelated type).

     The *note tp_new: 582. function should call
     ‘subtype->tp_alloc(subtype, nitems)’ to allocate space for the
     object, and then do only as much further initialization as is
     absolutely necessary.  Initialization that can safely be ignored or
     repeated should be placed in the *note tp_init: 584. handler.  A
     good rule of thumb is that for immutable types, all initialization
     should take place in ‘tp_new’, while for mutable types, most
     initialization should be deferred to ‘tp_init’.

     Set the *note Py_TPFLAGS_DISALLOW_INSTANTIATION: 585. flag to
     disallow creating instances of the type in Python.

     'Inheritance:'

     This field is inherited by subtypes, except it is not inherited by
     *note static types: 782. whose *note tp_base: 20d7. is ‘NULL’ or
     ‘&PyBaseObject_Type’.

     'Default:'

     For *note static types: 782. this field has no default.  This means
     if the slot is defined as ‘NULL’, the type cannot be called to
     create new instances; presumably there is some other way to create
     instances, like a factory function.

 -- C Member: *note freefunc: 50e7. *note PyTypeObject: aba.tp_free

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_free’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to an instance deallocation function.  Its
     signature is:

          void tp_free(void *self);

     An initializer that is compatible with this signature is *note
     PyObject_Free(): c86.

     'Inheritance:'

     This field is inherited by static subtypes, but not by dynamic
     subtypes (subtypes created by a class statement)

     'Default:'

     In dynamic subtypes, this field is set to a deallocator suitable to
     match *note PyType_GenericAlloc(): a7a. and the value of the *note
     Py_TPFLAGS_HAVE_GC: 780. flag bit.

     For static subtypes, *note PyBaseObject_Type: 4c37. uses *note
     PyObject_Del(): 1520.

 -- C Member: *note inquiry: 4e69. *note PyTypeObject: aba.tp_is_gc

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_is_gc’ is part of
     the *note Stable ABI: 556.'

     An optional pointer to a function called by the garbage collector.

     The garbage collector needs to know whether a particular object is
     collectible or not.  Normally, it is sufficient to look at the
     object’s type’s *note tp_flags: 1a18. field, and check the *note
     Py_TPFLAGS_HAVE_GC: 780. flag bit.  But some types have a mixture
     of statically and dynamically allocated instances, and the
     statically allocated instances are not collectible.  Such types
     should define this function; it should return ‘1’ for a collectible
     instance, and ‘0’ for a non-collectible instance.  The signature
     is:

          int tp_is_gc(PyObject *self);

     (The only example of this are types themselves.  The metatype,
     *note PyType_Type: 550, defines this function to distinguish
     between statically and *note dynamically allocated types: 96f.)

     'Inheritance:'

     This field is inherited by subtypes.

     'Default:'

     This slot has no default.  If this field is ‘NULL’, *note
     Py_TPFLAGS_HAVE_GC: 780. is used as the functional equivalent.

 -- C Member: *note PyObject: 33a. **note PyTypeObject: aba.tp_bases

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_bases’ is part of
     the *note Stable ABI: 556.'

     Tuple of base types.

     This field should be set to ‘NULL’ and treated as read-only.
     Python will fill it in when the type is *note initialized: 77f.

     For dynamically created classes, the ‘Py_tp_bases’ *note slot:
     4da4. can be used instead of the 'bases' argument of *note
     PyType_FromSpecWithBases(): 581.  The argument form is preferred.

          Warning: Multiple inheritance does not work well for
          statically defined types.  If you set ‘tp_bases’ to a tuple,
          Python will not raise an error, but some slots will only be
          inherited from the first base.

     'Inheritance:'

     This field is not inherited.

 -- C Member: *note PyObject: 33a. **note PyTypeObject: aba.tp_mro

     Tuple containing the expanded set of base types, starting with the
     type itself and ending with *note object: a9b, in Method Resolution
     Order.

     This field should be set to ‘NULL’ and treated as read-only.
     Python will fill it in when the type is *note initialized: 77f.

     'Inheritance:'

     This field is not inherited; it is calculated fresh by *note
     PyType_Ready(): 77f.

 -- C Member: *note PyObject: 33a. **note PyTypeObject: aba.tp_cache

     Unused.  Internal use only.

     'Inheritance:'

     This field is not inherited.

 -- C Member: void **note PyTypeObject: aba.tp_subclasses

     A collection of subclasses.  Internal use only.  May be an invalid
     pointer.

     To get a list of subclasses, call the Python method *note
     __subclasses__(): 576.

     Changed in version 3.12: For some types, this field does not hold a
     valid *note PyObject: 33a.*.  The type was changed to void* to
     indicate this.

     'Inheritance:'

     This field is not inherited.

 -- C Member: *note PyObject: 33a. **note PyTypeObject: aba.tp_weaklist

     Weak reference list head, for weak references to this type object.
     Not inherited.  Internal use only.

     Changed in version 3.12: Internals detail: For the static builtin
     types this is always ‘NULL’, even if weakrefs are added.  Instead,
     the weakrefs for each are stored on ‘PyInterpreterState’.  Use the
     public C-API or the internal ‘_PyObject_GET_WEAKREFS_LISTPTR()’
     macro to avoid the distinction.

     'Inheritance:'

     This field is not inherited.

 -- C Member: *note destructor: 4e61. *note PyTypeObject: aba.tp_del

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_del’ is part of the
     *note Stable ABI: 556.'

     This field is deprecated.  Use *note tp_finalize: abb. instead.

 -- C Member: unsigned int *note PyTypeObject: aba.tp_version_tag

     Used to index into the method cache.  Internal use only.

     'Inheritance:'

     This field is not inherited.

 -- C Member: *note destructor: 4e61. *note PyTypeObject:
          aba.tp_finalize

     ' The corresponding *note slot ID: 4da4. ‘Py_tp_finalize’ is part
     of the *note Stable ABI: 556. since version 3.5.'

     An optional pointer to an instance finalization function.  This is
     the C implementation of the *note __del__(): 1038. special method.
     Its signature is:

          void tp_finalize(PyObject *self);

     If *note tp_finalize: abb. is set, the interpreter calls it once
     when finalizing an instance.  It is called either from the garbage
     collector (if the instance is part of an isolated reference cycle)
     or just before the object is deallocated.  Either way, it is
     guaranteed to be called before attempting to break reference
     cycles, ensuring that it finds the object in a sane state.

     *note tp_finalize: abb. should not mutate the current exception
     status; therefore, a recommended way to write a non-trivial
     finalizer is:

          static void
          local_finalize(PyObject *self)
          {
              /* Save the current exception, if any. */
              PyObject *exc = PyErr_GetRaisedException();

              /* ... */

              /* Restore the saved exception. */
              PyErr_SetRaisedException(exc);
          }

     'Inheritance:'

     This field is inherited by subtypes.

     Added in version 3.4.

     Changed in version 3.8: Before version 3.8 it was necessary to set
     the *note Py_TPFLAGS_HAVE_FINALIZE: 3f5. flags bit in order for
     this field to be used.  This is no longer required.

     See also
     ........

     “Safe object finalization” ( PEP 442(4))

 -- C Member: *note vectorcallfunc: 55a. *note PyTypeObject:
          aba.tp_vectorcall

     Vectorcall function to use for calls of this type object.  In other
     words, it is used to implement *note vectorcall: 555. for
     ‘type.__call__’.  If ‘tp_vectorcall’ is ‘NULL’, the default call
     implementation using *note __new__(): 583. and *note __init__():
     6b3. is used.

     'Inheritance:'

     This field is never inherited.

     Added in version 3.9: (the field exists since 3.8 but it’s only
     used since 3.9)

 -- C Member: unsigned char *note PyTypeObject: aba.tp_watched

     Internal.  Do not use.

     Added in version 3.12.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0634/

   (2) https://peps.python.org/pep-0634/

   (3) https://bugs.python.org/issue40217

   (4) https://peps.python.org/pep-0442/


File: python.info,  Node: Static Types,  Next: Heap Types,  Prev: PyTypeObject Slots,  Up: Type Object Structures

7.12.3.9 Static Types
.....................

Traditionally, types defined in C code are 'static', that is, a static
*note PyTypeObject: aba. structure is defined directly in code and
initialized using *note PyType_Ready(): 77f.

This results in types that are limited relative to types defined in
Python:

   * Static types are limited to one base, i.e.  they cannot use
     multiple inheritance.

   * Static type objects (but not necessarily their instances) are
     immutable.  It is not possible to add or modify the type object’s
     attributes from Python.

   * Static type objects are shared across *note sub-interpreters: 58a,
     so they should not include any subinterpreter-specific state.

Also, since *note PyTypeObject: aba. is only part of the *note Limited
API: 399. as an opaque struct, any extension modules using static types
must be compiled for a specific Python minor version.


File: python.info,  Node: Heap Types,  Next: Number Object Structures,  Prev: Static Types,  Up: Type Object Structures

7.12.3.10 Heap Types
....................

An alternative to *note static types: 782. is 'heap-allocated types', or
'heap types' for short, which correspond closely to classes created by
Python’s ‘class’ statement.  Heap types have the *note
Py_TPFLAGS_HEAPTYPE: 8b7. flag set.

This is done by filling a *note PyType_Spec: 1828. structure and calling
*note PyType_FromSpec(): 580, *note PyType_FromSpecWithBases(): 581,
*note PyType_FromModuleAndSpec(): 554, or *note PyType_FromMetaclass():
553.


File: python.info,  Node: Number Object Structures,  Next: Mapping Object Structures,  Prev: Heap Types,  Up: Type Object Structures

7.12.3.11 Number Object Structures
..................................

 -- C Type: type PyNumberMethods

     This structure holds pointers to the functions which an object uses
     to implement the number protocol.  Each function is used by the
     function of similar name documented in the *note Number Protocol:
     4f51. section.

     Here is the structure definition:

          typedef struct {
               binaryfunc nb_add;
               binaryfunc nb_subtract;
               binaryfunc nb_multiply;
               binaryfunc nb_remainder;
               binaryfunc nb_divmod;
               ternaryfunc nb_power;
               unaryfunc nb_negative;
               unaryfunc nb_positive;
               unaryfunc nb_absolute;
               inquiry nb_bool;
               unaryfunc nb_invert;
               binaryfunc nb_lshift;
               binaryfunc nb_rshift;
               binaryfunc nb_and;
               binaryfunc nb_xor;
               binaryfunc nb_or;
               unaryfunc nb_int;
               void *nb_reserved;
               unaryfunc nb_float;

               binaryfunc nb_inplace_add;
               binaryfunc nb_inplace_subtract;
               binaryfunc nb_inplace_multiply;
               binaryfunc nb_inplace_remainder;
               ternaryfunc nb_inplace_power;
               binaryfunc nb_inplace_lshift;
               binaryfunc nb_inplace_rshift;
               binaryfunc nb_inplace_and;
               binaryfunc nb_inplace_xor;
               binaryfunc nb_inplace_or;

               binaryfunc nb_floor_divide;
               binaryfunc nb_true_divide;
               binaryfunc nb_inplace_floor_divide;
               binaryfunc nb_inplace_true_divide;

               unaryfunc nb_index;

               binaryfunc nb_matrix_multiply;
               binaryfunc nb_inplace_matrix_multiply;
          } PyNumberMethods;

          Note: Binary and ternary functions must check the type of all
          their operands, and implement the necessary conversions (at
          least one of the operands is an instance of the defined type).
          If the operation is not defined for the given operands, binary
          and ternary functions must return ‘Py_NotImplemented’, if
          another error occurred they must return ‘NULL’ and set an
          exception.

          Note: The *note nb_reserved: 52bc. field should always be
          ‘NULL’.  It was previously called ‘nb_long’, and was renamed
          in Python 3.0.1.

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods: 146c.nb_add

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_add’ is part of the
     *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_subtract

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_subtract’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_multiply

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_multiply’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_remainder

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_remainder’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_divmod

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_divmod’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note ternaryfunc: 4e77. *note PyNumberMethods:
          146c.nb_power

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_power’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_negative

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_negative’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_positive

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_positive’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_absolute

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_absolute’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note inquiry: 4e69. *note PyNumberMethods: 146c.nb_bool

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_bool’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_invert

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_invert’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_lshift

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_lshift’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_rshift

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_rshift’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods: 146c.nb_and

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_and’ is part of the
     *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods: 146c.nb_xor

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_xor’ is part of the
     *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods: 146c.nb_or

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_or’ is part of the
     *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods: 146c.nb_int

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_int’ is part of the
     *note Stable ABI: 556.'

 -- C Member: void **note PyNumberMethods: 146c.nb_reserved

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_float

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_float’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_add

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_add’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_subtract

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_subtract’
     is part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_multiply

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_multiply’
     is part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_remainder

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_remainder’
     is part of the *note Stable ABI: 556.'

 -- C Member: *note ternaryfunc: 4e77. *note PyNumberMethods:
          146c.nb_inplace_power

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_power’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_lshift

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_lshift’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_rshift

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_rshift’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_and

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_and’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_xor

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_xor’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_or

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_inplace_or’ is part
     of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_floor_divide

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_floor_divide’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_true_divide

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_true_divide’ is
     part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_floor_divide

     ' The corresponding *note slot ID: 4da4.
     ‘Py_nb_inplace_floor_divide’ is part of the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_true_divide

     ' The corresponding *note slot ID: 4da4.
     ‘Py_nb_inplace_true_divide’ is part of the *note Stable ABI: 556.'

 -- C Member: *note unaryfunc: 4e79. *note PyNumberMethods:
          146c.nb_index

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_index’ is part of
     the *note Stable ABI: 556.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_matrix_multiply

     ' The corresponding *note slot ID: 4da4. ‘Py_nb_matrix_multiply’ is
     part of the *note Stable ABI: 556. since version 3.5.'

 -- C Member: *note binaryfunc: 4e5e. *note PyNumberMethods:
          146c.nb_inplace_matrix_multiply

     ' The corresponding *note slot ID: 4da4.
     ‘Py_nb_inplace_matrix_multiply’ is part of the *note Stable ABI:
     556. since version 3.5.'


File: python.info,  Node: Mapping Object Structures,  Next: Sequence Object Structures,  Prev: Number Object Structures,  Up: Type Object Structures

7.12.3.12 Mapping Object Structures
...................................

 -- C Type: type PyMappingMethods

     This structure holds pointers to the functions which an object uses
     to implement the mapping protocol.  It has three members:

 -- C Member: *note lenfunc: 4e6b. *note PyMappingMethods:
          4bbf.mp_length

     ' The corresponding *note slot ID: 4da4. ‘Py_mp_length’ is part of
     the *note Stable ABI: 556.'

     This function is used by *note PyMapping_Size(): 1be8. and *note
     PyObject_Size(): 4d5e, and has the same signature.  This slot may
     be set to ‘NULL’ if the object has no defined length.

 -- C Member: *note binaryfunc: 4e5e. *note PyMappingMethods:
          4bbf.mp_subscript

     ' The corresponding *note slot ID: 4da4. ‘Py_mp_subscript’ is part
     of the *note Stable ABI: 556.'

     This function is used by *note PyObject_GetItem(): 348. and *note
     PySequence_GetSlice(): 4d6c, and has the same signature as
     ‘PyObject_GetItem()’.  This slot must be filled for the *note
     PyMapping_Check(): 4d16. function to return ‘1’, it can be ‘NULL’
     otherwise.

 -- C Member: *note objobjargproc: 4e6d. *note PyMappingMethods:
          4bbf.mp_ass_subscript

     ' The corresponding *note slot ID: 4da4. ‘Py_mp_ass_subscript’ is
     part of the *note Stable ABI: 556.'

     This function is used by *note PyObject_SetItem(): 4c0a, *note
     PyObject_DelItem(): 4d50, *note PySequence_SetSlice(): 4d73. and
     *note PySequence_DelSlice(): 4d6a.  It has the same signature as
     ‘PyObject_SetItem()’, but 'v' can also be set to ‘NULL’ to delete
     an item.  If this slot is ‘NULL’, the object does not support item
     assignment and deletion.


File: python.info,  Node: Sequence Object Structures,  Next: Buffer Object Structures,  Prev: Mapping Object Structures,  Up: Type Object Structures

7.12.3.13 Sequence Object Structures
....................................

 -- C Type: type PySequenceMethods

     This structure holds pointers to the functions which an object uses
     to implement the sequence protocol.

 -- C Member: *note lenfunc: 4e6b. *note PySequenceMethods:
          4bbe.sq_length

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_length’ is part of
     the *note Stable ABI: 556.'

     This function is used by *note PySequence_Size(): 1be4. and *note
     PyObject_Size(): 4d5e, and has the same signature.  It is also used
     for handling negative indices via the *note sq_item: 1a9c. and the
     *note sq_ass_item: 52c8. slots.

 -- C Member: *note binaryfunc: 4e5e. *note PySequenceMethods:
          4bbe.sq_concat

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_concat’ is part of
     the *note Stable ABI: 556.'

     This function is used by *note PySequence_Concat(): 4d67. and has
     the same signature.  It is also used by the ‘+’ operator, after
     trying the numeric addition via the *note nb_add: 4f96. slot.

 -- C Member: *note ssizeargfunc: 4e75. *note PySequenceMethods:
          4bbe.sq_repeat

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_repeat’ is part of
     the *note Stable ABI: 556.'

     This function is used by *note PySequence_Repeat(): 4d72. and has
     the same signature.  It is also used by the ‘*’ operator, after
     trying numeric multiplication via the *note nb_multiply: 52a5.
     slot.

 -- C Member: *note ssizeargfunc: 4e75. *note PySequenceMethods:
          4bbe.sq_item

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_item’ is part of
     the *note Stable ABI: 556.'

     This function is used by *note PySequence_GetItem(): 1be5. and has
     the same signature.  It is also used by *note PyObject_GetItem():
     348, after trying the subscription via the *note mp_subscript:
     1a9d. slot.  This slot must be filled for the *note
     PySequence_Check(): 4d66. function to return ‘1’, it can be ‘NULL’
     otherwise.

     Negative indexes are handled as follows: if the *note sq_length:
     4fa0. slot is filled, it is called and the sequence length is used
     to compute a positive index which is passed to *note sq_item: 1a9c.
     If ‘sq_length’ is ‘NULL’, the index is passed as is to the
     function.

 -- C Member: *note ssizeobjargproc: 4e76. *note PySequenceMethods:
          4bbe.sq_ass_item

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_ass_item’ is part
     of the *note Stable ABI: 556.'

     This function is used by *note PySequence_SetItem(): 1be6. and has
     the same signature.  It is also used by *note PyObject_SetItem():
     4c0a. and *note PyObject_DelItem(): 4d50, after trying the item
     assignment and deletion via the *note mp_ass_subscript: 52c5. slot.
     This slot may be left to ‘NULL’ if the object does not support item
     assignment and deletion.

 -- C Member: *note objobjproc: 4e6e. *note PySequenceMethods:
          4bbe.sq_contains

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_contains’ is part
     of the *note Stable ABI: 556.'

     This function may be used by *note PySequence_Contains(): 4d68. and
     has the same signature.  This slot may be left to ‘NULL’, in this
     case ‘PySequence_Contains()’ simply traverses the sequence until it
     finds a match.

 -- C Member: *note binaryfunc: 4e5e. *note PySequenceMethods:
          4bbe.sq_inplace_concat

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_inplace_concat’ is
     part of the *note Stable ABI: 556.'

     This function is used by *note PySequence_InPlaceConcat(): 4d6d.
     and has the same signature.  It should modify its first operand,
     and return it.  This slot may be left to ‘NULL’, in this case
     ‘PySequence_InPlaceConcat()’ will fall back to *note
     PySequence_Concat(): 4d67.  It is also used by the augmented
     assignment ‘+=’, after trying numeric in-place addition via the
     *note nb_inplace_add: 52a2. slot.

 -- C Member: *note ssizeargfunc: 4e75. *note PySequenceMethods:
          4bbe.sq_inplace_repeat

     ' The corresponding *note slot ID: 4da4. ‘Py_sq_inplace_repeat’ is
     part of the *note Stable ABI: 556.'

     This function is used by *note PySequence_InPlaceRepeat(): 4d6e.
     and has the same signature.  It should modify its first operand,
     and return it.  This slot may be left to ‘NULL’, in this case
     ‘PySequence_InPlaceRepeat()’ will fall back to *note
     PySequence_Repeat(): 4d72.  It is also used by the augmented
     assignment ‘*=’, after trying numeric in-place multiplication via
     the *note nb_inplace_multiply: 52a6. slot.


File: python.info,  Node: Buffer Object Structures,  Next: Async Object Structures,  Prev: Sequence Object Structures,  Up: Type Object Structures

7.12.3.14 Buffer Object Structures
..................................

 -- C Type: type PyBufferProcs

     This structure holds pointers to the functions required by the
     *note Buffer protocol: 2e8.  The protocol defines how an exporter
     object can expose its internal data to consumer objects.

 -- C Member: *note getbufferproc: 4e64. *note PyBufferProcs:
          4fa7.bf_getbuffer

     ' The corresponding *note slot ID: 4da4. ‘Py_bf_getbuffer’ is part
     of the *note Stable ABI: 556. since version 3.11.'

     The signature of this function is:

          int (PyObject *exporter, Py_buffer *view, int flags);

     Handle a request to 'exporter' to fill in 'view' as specified by
     'flags'.  Except for point (3), an implementation of this function
     MUST take these steps:

       1. Check if the request can be met.  If not, raise *note
          BufferError: 15e3, set view->obj to ‘NULL’ and return ‘-1’.

       2. Fill in the requested fields.

       3. Increment an internal counter for the number of exports.

       4. Set view->obj to 'exporter' and increment view->obj.

       5. Return ‘0’.

     If 'exporter' is part of a chain or tree of buffer providers, two
     main schemes can be used:

        * Re-export: Each member of the tree acts as the exporting
          object and sets view->obj to a new reference to itself.

        * Redirect: The buffer request is redirected to the root object
          of the tree.  Here, view->obj will be a new reference to the
          root object.

     The individual fields of 'view' are described in section *note
     Buffer structure: 4f6c, the rules how an exporter must react to
     specific requests are in section *note Buffer request types: 4726.

     All memory pointed to in the *note Py_buffer: 75b. structure
     belongs to the exporter and must remain valid until there are no
     consumers left.  *note format: 4f75, *note shape: 4f76, *note
     strides: 4f70, *note suboffsets: 4f78. and *note internal: 4f7a.
     are read-only for the consumer.

     *note PyBuffer_FillInfo(): 763. provides an easy way of exposing a
     simple bytes buffer while dealing correctly with all request types.

     *note PyObject_GetBuffer(): 39c. is the interface for the consumer
     that wraps this function.

 -- C Member: *note releasebufferproc: 4e6f. *note PyBufferProcs:
          4fa7.bf_releasebuffer

     ' The corresponding *note slot ID: 4da4. ‘Py_bf_releasebuffer’ is
     part of the *note Stable ABI: 556. since version 3.11.'

     The signature of this function is:

          void (PyObject *exporter, Py_buffer *view);

     Handle a request to release the resources of the buffer.  If no
     resources need to be released, *note
     PyBufferProcs.bf_releasebuffer: 766. may be ‘NULL’.  Otherwise, a
     standard implementation of this function will take these optional
     steps:

       1. Decrement an internal counter for the number of exports.

       2. If the counter is ‘0’, free all memory associated with 'view'.

     The exporter MUST use the *note internal: 4f7a. field to keep track
     of buffer-specific resources.  This field is guaranteed to remain
     constant, while a consumer MAY pass a copy of the original buffer
     as the 'view' argument.

     This function MUST NOT decrement view->obj, since that is done
     automatically in *note PyBuffer_Release(): 39d. (this scheme is
     useful for breaking reference cycles).

     *note PyBuffer_Release(): 39d. is the interface for the consumer
     that wraps this function.


File: python.info,  Node: Async Object Structures,  Next: Slot Type typedefs,  Prev: Buffer Object Structures,  Up: Type Object Structures

7.12.3.15 Async Object Structures
.................................

Added in version 3.5.

 -- C Type: type PyAsyncMethods

     This structure holds pointers to the functions required to
     implement *note awaitable: 1ad. and *note asynchronous iterator:
     1ab. objects.

     Here is the structure definition:

          typedef struct {
              unaryfunc am_await;
              unaryfunc am_aiter;
              unaryfunc am_anext;
              sendfunc am_send;
          } PyAsyncMethods;

 -- C Member: *note unaryfunc: 4e79. *note PyAsyncMethods: 4f9f.am_await

     ' The corresponding *note slot ID: 4da4. ‘Py_am_await’ is part of
     the *note Stable ABI: 556. since version 3.5.'

     The signature of this function is:

          PyObject *am_await(PyObject *self);

     The returned object must be an *note iterator: 1ac, i.e.  *note
     PyIter_Check(): 1a58. must return ‘1’ for it.

     This slot may be set to ‘NULL’ if an object is not an *note
     awaitable: 1ad.

 -- C Member: *note unaryfunc: 4e79. *note PyAsyncMethods: 4f9f.am_aiter

     ' The corresponding *note slot ID: 4da4. ‘Py_am_aiter’ is part of
     the *note Stable ABI: 556. since version 3.5.'

     The signature of this function is:

          PyObject *am_aiter(PyObject *self);

     Must return an *note asynchronous iterator: 1ab. object.  See *note
     __anext__(): 1678. for details.

     This slot may be set to ‘NULL’ if an object does not implement
     asynchronous iteration protocol.

 -- C Member: *note unaryfunc: 4e79. *note PyAsyncMethods: 4f9f.am_anext

     ' The corresponding *note slot ID: 4da4. ‘Py_am_anext’ is part of
     the *note Stable ABI: 556. since version 3.5.'

     The signature of this function is:

          PyObject *am_anext(PyObject *self);

     Must return an *note awaitable: 1ad. object.  See *note
     __anext__(): 1678. for details.  This slot may be set to ‘NULL’.

 -- C Member: *note sendfunc: 52a1. *note PyAsyncMethods: 4f9f.am_send

     ' The corresponding *note slot ID: 4da4. ‘Py_am_send’ is part of
     the *note Stable ABI: 556. since version 3.10.'

     The signature of this function is:

          PySendResult am_send(PyObject *self, PyObject *arg, PyObject **result);

     See *note PyIter_Send(): 89f. for details.  This slot may be set to
     ‘NULL’.

     Added in version 3.10.


File: python.info,  Node: Slot Type typedefs,  Next: Examples<38>,  Prev: Async Object Structures,  Up: Type Object Structures

7.12.3.16 Slot Type typedefs
............................

 -- C Type: typedef *note PyObject: 33a. *(*allocfunc)(*note
          PyTypeObject: aba. *cls, *note Py_ssize_t: a6e. nitems)
     ' Part of the *note Stable ABI: 556.'  The purpose of this function
     is to separate memory allocation from memory initialization.  It
     should return a pointer to a block of memory of adequate length for
     the instance, suitably aligned, and initialized to zeros, but with
     *note ob_refcnt: 8a6. set to ‘1’ and *note ob_type: 4b98. set to
     the type argument.  If the type’s *note tp_itemsize: 2121. is
     non-zero, the object’s *note ob_size: 4de3. field should be
     initialized to 'nitems' and the length of the allocated memory
     block should be ‘tp_basicsize + nitems*tp_itemsize’, rounded up to
     a multiple of ‘sizeof(void*)’; otherwise, 'nitems' is not used and
     the length of the block should be *note tp_basicsize: 991.

     This function should not do any other instance initialization, not
     even to allocate additional memory; that should be done by *note
     tp_new: 582.

 -- C Type: typedef void (*destructor)(*note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef void (*freefunc)(void*)

     See *note tp_free: 4b9a.

 -- C Type: typedef *note PyObject: 33a. *(*newfunc)(*note PyTypeObject:
          aba.*, *note PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_new: 582.

 -- C Type: typedef int (*initproc)(*note PyObject: 33a.*, *note
          PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_init: 584.

 -- C Type: typedef *note PyObject: 33a. *(*reprfunc)(*note PyObject:
          33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_repr: 4bae.

 -- C Type: typedef *note PyObject: 33a. *(*getattrfunc)(*note PyObject:
          33a. *self, char *attr)
     ' Part of the *note Stable ABI: 556.'  Return the value of the
     named attribute for the object.

 -- C Type: typedef int (*setattrfunc)(*note PyObject: 33a. *self, char
          *attr, *note PyObject: 33a. *value)
     ' Part of the *note Stable ABI: 556.'  Set the value of the named
     attribute for the object.  The value argument is set to ‘NULL’ to
     delete the attribute.

 -- C Type: typedef *note PyObject: 33a. *(*getattrofunc)(*note
          PyObject: 33a. *self, *note PyObject: 33a. *attr)
     ' Part of the *note Stable ABI: 556.'  Return the value of the
     named attribute for the object.

     See *note tp_getattro: 1803.

 -- C Type: typedef int (*setattrofunc)(*note PyObject: 33a. *self,
          *note PyObject: 33a. *attr, *note PyObject: 33a. *value)
     ' Part of the *note Stable ABI: 556.'  Set the value of the named
     attribute for the object.  The value argument is set to ‘NULL’ to
     delete the attribute.

     See *note tp_setattro: 4bb2.

 -- C Type: typedef *note PyObject: 33a. *(*descrgetfunc)(*note
          PyObject: 33a.*, *note PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_descr_get:
     5296.

 -- C Type: typedef int (*descrsetfunc)(*note PyObject: 33a.*, *note
          PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_descr_set:
     1a5a.

 -- C Type: typedef *note Py_hash_t: 12aa. (*hashfunc)(*note PyObject:
          33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_hash: 4bc0.

 -- C Type: typedef *note PyObject: 33a. *(*richcmpfunc)(*note PyObject:
          33a.*, *note PyObject: 33a.*, int)
     ' Part of the *note Stable ABI: 556.'  See *note tp_richcompare:
     4bba.

 -- C Type: typedef *note PyObject: 33a. *(*getiterfunc)(*note PyObject:
          33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_iter: 153e.

 -- C Type: typedef *note PyObject: 33a. *(*iternextfunc)(*note
          PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'  See *note tp_iternext: 153f.

 -- C Type: typedef *note Py_ssize_t: a6e. (*lenfunc)(*note PyObject:
          33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef int (*getbufferproc)(*note PyObject: 33a.*, *note
          Py_buffer: 75b.*, int)
     ' Part of the *note Stable ABI: 556. since version 3.12.'

 -- C Type: typedef void (*releasebufferproc)(*note PyObject: 33a.*,
          *note Py_buffer: 75b.*)
     ' Part of the *note Stable ABI: 556. since version 3.12.'

 -- C Type: typedef *note PyObject: 33a. *(*unaryfunc)(*note PyObject:
          33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef *note PyObject: 33a. *(*binaryfunc)(*note PyObject:
          33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef *note PySendResult: 4f67. (*sendfunc)(*note
          PyObject: 33a.*, *note PyObject: 33a.*, *note PyObject:
          33a.**)

     See *note am_send: 52a0.

 -- C Type: typedef *note PyObject: 33a. *(*ternaryfunc)(*note PyObject:
          33a.*, *note PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef *note PyObject: 33a. *(*ssizeargfunc)(*note
          PyObject: 33a.*, *note Py_ssize_t: a6e.)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef int (*ssizeobjargproc)(*note PyObject: 33a.*, *note
          Py_ssize_t: a6e, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef int (*objobjproc)(*note PyObject: 33a.*, *note
          PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'

 -- C Type: typedef int (*objobjargproc)(*note PyObject: 33a.*, *note
          PyObject: 33a.*, *note PyObject: 33a.*)
     ' Part of the *note Stable ABI: 556.'


File: python.info,  Node: Examples<38>,  Prev: Slot Type typedefs,  Up: Type Object Structures

7.12.3.17 Examples
..................

The following are simple examples of Python type definitions.  They
include common usage you may encounter.  Some demonstrate tricky corner
cases.  For more examples, practical info, and a tutorial, see *note
Defining Extension Types; Tutorial: 4b90. and *note Defining Extension
Types; Assorted Topics: 4ba8.

A basic *note static type: 782.:

     typedef struct {
         PyObject_HEAD
         const char *data;
     } MyObject;

     static PyTypeObject MyObject_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "mymod.MyObject",
         .tp_basicsize = sizeof(MyObject),
         .tp_doc = PyDoc_STR("My objects"),
         .tp_new = myobj_new,
         .tp_dealloc = (destructor)myobj_dealloc,
         .tp_repr = (reprfunc)myobj_repr,
     };

You may also find older code (especially in the CPython code base) with
a more verbose initializer:

     static PyTypeObject MyObject_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         "mymod.MyObject",               /* tp_name */
         sizeof(MyObject),               /* tp_basicsize */
         0,                              /* tp_itemsize */
         (destructor)myobj_dealloc,      /* tp_dealloc */
         0,                              /* tp_vectorcall_offset */
         0,                              /* tp_getattr */
         0,                              /* tp_setattr */
         0,                              /* tp_as_async */
         (reprfunc)myobj_repr,           /* tp_repr */
         0,                              /* tp_as_number */
         0,                              /* tp_as_sequence */
         0,                              /* tp_as_mapping */
         0,                              /* tp_hash */
         0,                              /* tp_call */
         0,                              /* tp_str */
         0,                              /* tp_getattro */
         0,                              /* tp_setattro */
         0,                              /* tp_as_buffer */
         0,                              /* tp_flags */
         PyDoc_STR("My objects"),        /* tp_doc */
         0,                              /* tp_traverse */
         0,                              /* tp_clear */
         0,                              /* tp_richcompare */
         0,                              /* tp_weaklistoffset */
         0,                              /* tp_iter */
         0,                              /* tp_iternext */
         0,                              /* tp_methods */
         0,                              /* tp_members */
         0,                              /* tp_getset */
         0,                              /* tp_base */
         0,                              /* tp_dict */
         0,                              /* tp_descr_get */
         0,                              /* tp_descr_set */
         0,                              /* tp_dictoffset */
         0,                              /* tp_init */
         0,                              /* tp_alloc */
         myobj_new,                      /* tp_new */
     };

A type that supports weakrefs, instance dicts, and hashing:

     typedef struct {
         PyObject_HEAD
         const char *data;
     } MyObject;

     static PyTypeObject MyObject_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "mymod.MyObject",
         .tp_basicsize = sizeof(MyObject),
         .tp_doc = PyDoc_STR("My objects"),
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
              Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_MANAGED_DICT |
              Py_TPFLAGS_MANAGED_WEAKREF,
         .tp_new = myobj_new,
         .tp_traverse = (traverseproc)myobj_traverse,
         .tp_clear = (inquiry)myobj_clear,
         .tp_alloc = PyType_GenericNew,
         .tp_dealloc = (destructor)myobj_dealloc,
         .tp_repr = (reprfunc)myobj_repr,
         .tp_hash = (hashfunc)myobj_hash,
         .tp_richcompare = PyBaseObject_Type.tp_richcompare,
     };

A str subclass that cannot be subclassed and cannot be called to create
instances (e.g.  uses a separate factory func) using *note
Py_TPFLAGS_DISALLOW_INSTANTIATION: 585. flag:

     typedef struct {
         PyUnicodeObject raw;
         char *extra;
     } MyStr;

     static PyTypeObject MyStr_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "mymod.MyStr",
         .tp_basicsize = sizeof(MyStr),
         .tp_base = NULL,  // set to &PyUnicode_Type in module init
         .tp_doc = PyDoc_STR("my custom str"),
         .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,
         .tp_repr = (reprfunc)myobj_repr,
     };

The simplest *note static type: 782. with fixed-length instances:

     typedef struct {
         PyObject_HEAD
     } MyObject;

     static PyTypeObject MyObject_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "mymod.MyObject",
     };

The simplest *note static type: 782. with variable-length instances:

     typedef struct {
         PyObject_VAR_HEAD
         const char *data[1];
     } MyObject;

     static PyTypeObject MyObject_Type = {
         PyVarObject_HEAD_INIT(NULL, 0)
         .tp_name = "mymod.MyObject",
         .tp_basicsize = sizeof(MyObject) - sizeof(char *),
         .tp_itemsize = sizeof(char *),
     };


File: python.info,  Node: Supporting Cyclic Garbage Collection,  Prev: Type Object Structures,  Up: Object Implementation Support

7.12.4 Supporting Cyclic Garbage Collection
-------------------------------------------

Python’s support for detecting and collecting garbage which involves
circular references requires support from object types which are
“containers” for other objects which may also be containers.  Types
which do not store references to other objects, or which only store
references to atomic types (such as numbers or strings), do not need to
provide any explicit support for garbage collection.

To create a container type, the *note tp_flags: 1a18. field of the type
object must include the *note Py_TPFLAGS_HAVE_GC: 780. and provide an
implementation of the *note tp_traverse: 781. handler.  If instances of
the type are mutable, a *note tp_clear: 4bac. implementation must also
be provided.

*note Py_TPFLAGS_HAVE_GC: 780.

     Objects with a type with this flag set must conform with the rules
     documented here.  For convenience these objects will be referred to
     as container objects.

Constructors for container types must conform to two rules:

  1. The memory for the object must be allocated using *note
     PyObject_GC_New: ab7. or *note PyObject_GC_NewVar: ab8.

  2. Once all the fields which may contain references to other
     containers are initialized, it must call *note PyObject_GC_Track():
     1554.

Similarly, the deallocator for the object must conform to a similar pair
of rules:

  1. Before fields which refer to other containers are invalidated,
     *note PyObject_GC_UnTrack(): 1555. must be called.

  2. The object’s memory must be deallocated using *note
     PyObject_GC_Del(): 1553.

          Warning: If a type adds the Py_TPFLAGS_HAVE_GC, then it 'must'
          implement at least a *note tp_traverse: 781. handler or
          explicitly use one from its subclass or subclasses.

          When calling *note PyType_Ready(): 77f. or some of the APIs
          that indirectly call it like *note PyType_FromSpecWithBases():
          581. or *note PyType_FromSpec(): 580. the interpreter will
          automatically populate the *note tp_flags: 1a18, *note
          tp_traverse: 781. and *note tp_clear: 4bac. fields if the type
          inherits from a class that implements the garbage collector
          protocol and the child class does 'not' include the *note
          Py_TPFLAGS_HAVE_GC: 780. flag.

 -- C Macro: PyObject_GC_New (TYPE, typeobj)

     Analogous to *note PyObject_New: 98f. but for container objects
     with the *note Py_TPFLAGS_HAVE_GC: 780. flag set.

 -- C Macro: PyObject_GC_NewVar (TYPE, typeobj, size)

     Analogous to *note PyObject_NewVar: 990. but for container objects
     with the *note Py_TPFLAGS_HAVE_GC: 780. flag set.

 -- C Function: *note PyObject: 33a.
          *PyUnstable_Object_GC_NewWithExtraData (PyTypeObject *type,
          size_t extra_size)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Analogous to *note PyObject_GC_New: ab7. but allocates 'extra_size'
     bytes at the end of the object (at offset *note tp_basicsize:
     991.).  The allocated memory is initialized to zeros, except for
     the *note Python object header: 33a.

     The extra data will be deallocated with the object, but otherwise
     it is not managed by Python.

          Warning: The function is marked as unstable because the final
          mechanism for reserving extra data after an instance is not
          yet decided.  For allocating a variable number of fields,
          prefer using *note PyVarObject: 43a6. and *note tp_itemsize:
          2121. instead.

     Added in version 3.12.

 -- C Macro: PyObject_GC_Resize (TYPE, op, newsize)

     Resize an object allocated by *note PyObject_NewVar: 990.  Returns
     the resized object of type ‘TYPE*’ (refers to any C type) or ‘NULL’
     on failure.

     'op' must be of type *note PyVarObject: 43a6.* and must not be
     tracked by the collector yet.  'newsize' must be of type *note
     Py_ssize_t: a6e.

 -- C Function: void PyObject_GC_Track (PyObject *op)
     ' Part of the *note Stable ABI: 556.'  Adds the object 'op' to the
     set of container objects tracked by the collector.  The collector
     can run at unexpected times so objects must be valid while being
     tracked.  This should be called once all the fields followed by the
     *note tp_traverse: 781. handler become valid, usually near the end
     of the constructor.

 -- C Function: int PyObject_IS_GC (PyObject *obj)

     Returns non-zero if the object implements the garbage collector
     protocol, otherwise returns 0.

     The object cannot be tracked by the garbage collector if this
     function returns 0.

 -- C Function: int PyObject_GC_IsTracked (PyObject *op)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Returns 1
     if the object type of 'op' implements the GC protocol and 'op' is
     being currently tracked by the garbage collector and 0 otherwise.

     This is analogous to the Python function *note gc.is_tracked():
     1357.

     Added in version 3.9.

 -- C Function: int PyObject_GC_IsFinalized (PyObject *op)
     ' Part of the *note Stable ABI: 556. since version 3.9.'  Returns 1
     if the object type of 'op' implements the GC protocol and 'op' has
     been already finalized by the garbage collector and 0 otherwise.

     This is analogous to the Python function *note gc.is_finalized():
     906.

     Added in version 3.9.

 -- C Function: void PyObject_GC_Del (void *op)
     ' Part of the *note Stable ABI: 556.'  Releases memory allocated to
     an object using *note PyObject_GC_New: ab7. or *note
     PyObject_GC_NewVar: ab8.

 -- C Function: void PyObject_GC_UnTrack (void *op)
     ' Part of the *note Stable ABI: 556.'  Remove the object 'op' from
     the set of container objects tracked by the collector.  Note that
     *note PyObject_GC_Track(): 1554. can be called again on this object
     to add it back to the set of tracked objects.  The deallocator
     (*note tp_dealloc: 4b87. handler) should call this for the object
     before any of the fields used by the *note tp_traverse: 781.
     handler become invalid.

Changed in version 3.8: The ‘_PyObject_GC_TRACK()’ and
‘_PyObject_GC_UNTRACK()’ macros have been removed from the public C API.

The *note tp_traverse: 781. handler accepts a function parameter of this
type:

 -- C Type: typedef int (*visitproc)(*note PyObject: 33a. *object, void
          *arg)
     ' Part of the *note Stable ABI: 556.'  Type of the visitor function
     passed to the *note tp_traverse: 781. handler.  The function should
     be called with an object to traverse as 'object' and the third
     parameter to the ‘tp_traverse’ handler as 'arg'.  The Python core
     uses several visitor functions to implement cyclic garbage
     detection; it’s not expected that users will need to write their
     own visitor functions.

The *note tp_traverse: 781. handler must have the following type:

 -- C Type: typedef int (*traverseproc)(*note PyObject: 33a. *self,
          *note visitproc: 4e7a. visit, void *arg)
     ' Part of the *note Stable ABI: 556.'  Traversal function for a
     container object.  Implementations must call the 'visit' function
     for each object directly contained by 'self', with the parameters
     to 'visit' being the contained object and the 'arg' value passed to
     the handler.  The 'visit' function must not be called with a ‘NULL’
     object argument.  If 'visit' returns a non-zero value that value
     should be returned immediately.

     The traversal function must not have any side effects.
     Implementations may not modify the reference counts of any Python
     objects nor create or destroy any Python objects.

To simplify writing *note tp_traverse: 781. handlers, a *note
Py_VISIT(): 4ba3. macro is provided.  In order to use this macro, the
‘tp_traverse’ implementation must name its arguments exactly 'visit' and
'arg':

 -- C Macro: Py_VISIT (o)

     If the *note PyObject: 33a.* 'o' is not ‘NULL’, call the 'visit'
     callback, with arguments 'o' and 'arg'.  If 'visit' returns a
     non-zero value, then return it.  Using this macro, *note
     tp_traverse: 781. handlers look like:

          static int
          my_traverse(Noddy *self, visitproc visit, void *arg)
          {
              Py_VISIT(self->foo);
              Py_VISIT(self->bar);
              return 0;
          }

The *note tp_clear: 4bac. handler must be of the *note inquiry: 4e69.
type, or ‘NULL’ if the object is immutable.

 -- C Type: typedef int (*inquiry)(*note PyObject: 33a. *self)
     ' Part of the *note Stable ABI: 556.'  Drop references that may
     have created reference cycles.  Immutable objects do not have to
     define this method since they can never directly create reference
     cycles.  Note that the object must still be valid after calling
     this method (don’t just call *note Py_DECREF(): 572. on a
     reference).  The collector will call this method if it detects that
     this object is involved in a reference cycle.

* Menu:

* Controlling the Garbage Collector State::
* Querying Garbage Collector State::


File: python.info,  Node: Controlling the Garbage Collector State,  Next: Querying Garbage Collector State,  Up: Supporting Cyclic Garbage Collection

7.12.4.1 Controlling the Garbage Collector State
................................................

The C-API provides the following functions for controlling garbage
collection runs.

 -- C Function: *note Py_ssize_t: a6e. PyGC_Collect (void)
     ' Part of the *note Stable ABI: 556.'  Perform a full garbage
     collection, if the garbage collector is enabled.  (Note that *note
     gc.collect(): a47. runs it unconditionally.)

     Returns the number of collected + unreachable objects which cannot
     be collected.  If the garbage collector is disabled or already
     collecting, returns ‘0’ immediately.  Errors during garbage
     collection are passed to *note sys.unraisablehook: 1f7.  This
     function does not raise exceptions.

 -- C Function: int PyGC_Enable (void)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Enable
     the garbage collector: similar to *note gc.enable(): 46d2.  Returns
     the previous state, 0 for disabled and 1 for enabled.

     Added in version 3.10.

 -- C Function: int PyGC_Disable (void)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Disable
     the garbage collector: similar to *note gc.disable(): 46d3.
     Returns the previous state, 0 for disabled and 1 for enabled.

     Added in version 3.10.

 -- C Function: int PyGC_IsEnabled (void)
     ' Part of the *note Stable ABI: 556. since version 3.10.'  Query
     the state of the garbage collector: similar to *note
     gc.isenabled(): 46d4.  Returns the current state, 0 for disabled
     and 1 for enabled.

     Added in version 3.10.


File: python.info,  Node: Querying Garbage Collector State,  Prev: Controlling the Garbage Collector State,  Up: Supporting Cyclic Garbage Collection

7.12.4.2 Querying Garbage Collector State
.........................................

The C-API provides the following interface for querying information
about the garbage collector.

 -- C Function: void PyUnstable_GC_VisitObjects (gcvisitobjects_t
          callback, void *arg)

          This is Unstable API. It may change without warning in minor releases. 'This is *note Unstable API: 54a. It may change without warning in minor releases.': 
     Run supplied 'callback' on all live GC-capable objects.  'arg' is
     passed through to all invocations of 'callback'.

          Warning: If new objects are (de)allocated by the callback it
          is undefined if they will be visited.

          Garbage collection is disabled during operation.  Explicitly
          running a collection in the callback may lead to undefined
          behaviour e.g.  visiting the same objects multiple times or
          not at all.

     Added in version 3.12.

 -- C Type: typedef int (*gcvisitobjects_t)(*note PyObject: 33a.
          *object, void *arg)

     Type of the visitor function to be passed to *note
     PyUnstable_GC_VisitObjects(): 52f3.  'arg' is the same as the 'arg'
     passed to ‘PyUnstable_GC_VisitObjects’.  Return ‘1’ to continue
     iteration, return ‘0’ to stop iteration.  Other return values are
     reserved for now so behavior on returning anything else is
     undefined.

     Added in version 3.12.


File: python.info,  Node: API and ABI Versioning,  Next: Monitoring C API,  Prev: Object Implementation Support,  Up: Python/C API Reference Manual

7.13 API and ABI Versioning
===========================

CPython exposes its version number in the following macros.  Note that
these correspond to the version code is 'built' with, not necessarily
the version used at 'run time'.

See *note C API Stability: 556. for a discussion of API and ABI
stability across versions.

 -- C Macro: PY_MAJOR_VERSION

     The ‘3’ in ‘3.4.1a2’.

 -- C Macro: PY_MINOR_VERSION

     The ‘4’ in ‘3.4.1a2’.

 -- C Macro: PY_MICRO_VERSION

     The ‘1’ in ‘3.4.1a2’.

 -- C Macro: PY_RELEASE_LEVEL

     The ‘a’ in ‘3.4.1a2’.  This can be ‘0xA’ for alpha, ‘0xB’ for beta,
     ‘0xC’ for release candidate or ‘0xF’ for final.

 -- C Macro: PY_RELEASE_SERIAL

     The ‘2’ in ‘3.4.1a2’.  Zero for final releases.

 -- C Macro: PY_VERSION_HEX

     The Python version number encoded in a single integer.

     The underlying version information can be found by treating it as a
     32 bit number in the following manner:

     Bytes       Bits (big endian order)       Meaning                       Value for ‘3.4.1a2’
                                                                             
     -------------------------------------------------------------------------------------------------------
                                                                             
     1           1-8                           ‘PY_MAJOR_VERSION’            ‘0x03’
                                                                             
                                                                             
     2           9-16                          ‘PY_MINOR_VERSION’            ‘0x04’
                                                                             
                                                                             
     3           17-24                         ‘PY_MICRO_VERSION’            ‘0x01’
                                                                             
                                                                             
     4           25-28                         ‘PY_RELEASE_LEVEL’            ‘0xA’
                                                                             
                                               
     29-32       ‘PY_RELEASE_SERIAL’           ‘0x2’
                                               

     Thus ‘3.4.1a2’ is hexversion ‘0x030401a2’ and ‘3.10.0’ is
     hexversion ‘0x030a00f0’.

     Use this for numeric comparisons, e.g.  ‘#if PY_VERSION_HEX >=
     ...’.

     This version is also available via the symbol *note Py_Version:
     759.

 -- C Variable: const unsigned long Py_Version
     ' Part of the *note Stable ABI: 556. since version 3.11.'  The
     Python runtime version number encoded in a single constant integer,
     with the same format as the *note PY_VERSION_HEX: 75a. macro.  This
     contains the Python version used at run time.

     Added in version 3.11.

All the given macros are defined in Include/patchlevel.h(1).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Include/patchlevel.h


File: python.info,  Node: Monitoring C API,  Next: Generating Execution Events,  Prev: API and ABI Versioning,  Up: Python/C API Reference Manual

7.14 Monitoring C API
=====================

Added in version 3.13.

An extension may need to interact with the event monitoring system.
Subscribing to events and registering callbacks can be done via the
Python API exposed in *note sys.monitoring: da.


File: python.info,  Node: Generating Execution Events,  Prev: Monitoring C API,  Up: Python/C API Reference Manual

7.15 Generating Execution Events
================================

The functions below make it possible for an extension to fire monitoring
events as it emulates the execution of Python code.  Each of these
functions accepts a ‘PyMonitoringState’ struct which contains concise
information about the activation state of events, as well as the event
arguments, which include a ‘PyObject*’ representing the code object, the
instruction offset and sometimes additional, event-specific arguments
(see *note sys.monitoring: da. for details about the signatures of the
different event callbacks).  The ‘codelike’ argument should be an
instance of *note types.CodeType: 2df. or of a type that emulates it.

The VM disables tracing when firing an event, so there is no need for
user code to do that.

Monitoring functions should not be called with an exception set, except
those listed below as working with the current exception.

 -- C Type: type PyMonitoringState

     Representation of the state of an event type.  It is allocated by
     the user while its contents are maintained by the monitoring API
     functions described below.

All of the functions below return 0 on success and -1 (with an exception
set) on error.

See *note sys.monitoring: da. for descriptions of the events.

 -- C Function: int PyMonitoring_FirePyStartEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘PY_START’ event.

 -- C Function: int PyMonitoring_FirePyResumeEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘PY_RESUME’ event.

 -- C Function: int PyMonitoring_FirePyReturnEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject *retval)

     Fire a ‘PY_RETURN’ event.

 -- C Function: int PyMonitoring_FirePyYieldEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject *retval)

     Fire a ‘PY_YIELD’ event.

 -- C Function: int PyMonitoring_FireCallEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject
          *callable, PyObject *arg0)

     Fire a ‘CALL’ event.

 -- C Function: int PyMonitoring_FireLineEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, int lineno)

     Fire a ‘LINE’ event.

 -- C Function: int PyMonitoring_FireJumpEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject
          *target_offset)

     Fire a ‘JUMP’ event.

 -- C Function: int PyMonitoring_FireBranchEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject
          *target_offset)

     Fire a ‘BRANCH’ event.

 -- C Function: int PyMonitoring_FireCReturnEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset, PyObject *retval)

     Fire a ‘C_RETURN’ event.

 -- C Function: int PyMonitoring_FirePyThrowEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘PY_THROW’ event with the current exception (as returned by
     *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FireRaiseEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘RAISE’ event with the current exception (as returned by
     *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FireCRaiseEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘C_RAISE’ event with the current exception (as returned by
     *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FireReraiseEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘RERAISE’ event with the current exception (as returned by
     *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FireExceptionHandledEvent
          (PyMonitoringState *state, PyObject *codelike, int32_t offset)

     Fire an ‘EXCEPTION_HANDLED’ event with the current exception (as
     returned by *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FirePyUnwindEvent (PyMonitoringState
          *state, PyObject *codelike, int32_t offset)

     Fire a ‘PY_UNWIND’ event with the current exception (as returned by
     *note PyErr_GetRaisedException(): 3f7.).

 -- C Function: int PyMonitoring_FireStopIterationEvent
          (PyMonitoringState *state, PyObject *codelike, int32_t offset,
          PyObject *value)

     Fire a ‘STOP_ITERATION’ event.  If ‘value’ is an instance of *note
     StopIteration: c1b, it is used.  Otherwise, a new ‘StopIteration’
     instance is created with ‘value’ as its argument.

* Menu:

* Managing the Monitoring State::


File: python.info,  Node: Managing the Monitoring State,  Up: Generating Execution Events

7.15.1 Managing the Monitoring State
------------------------------------

Monitoring states can be managed with the help of monitoring scopes.  A
scope would typically correspond to a Python function.

 -- C Function: int PyMonitoring_EnterScope (PyMonitoringState
          *state_array, uint64_t *version, const uint8_t *event_types,
          Py_ssize_t length)

     Enter a monitored scope.  ‘event_types’ is an array of the event
     IDs for events that may be fired from the scope.  For example, the
     ID of a ‘PY_START’ event is the value
     ‘PY_MONITORING_EVENT_PY_START’, which is numerically equal to the
     base-2 logarithm of ‘sys.monitoring.events.PY_START’.
     ‘state_array’ is an array with a monitoring state entry for each
     event in ‘event_types’, it is allocated by the user but populated
     by ‘PyMonitoring_EnterScope()’ with information about the
     activation state of the event.  The size of ‘event_types’ (and
     hence also of ‘state_array’) is given in ‘length’.

     The ‘version’ argument is a pointer to a value which should be
     allocated by the user together with ‘state_array’ and initialized
     to 0, and then set only by ‘PyMonitoring_EnterScope()’ itself.  It
     allows this function to determine whether event states have changed
     since the previous call, and to return quickly if they have not.

     The scopes referred to here are lexical scopes: a function, class
     or method.  ‘PyMonitoring_EnterScope()’ should be called whenever
     the lexical scope is entered.  Scopes can be reentered, reusing the
     same 'state_array' and 'version', in situations like when emulating
     a recursive Python function.  When a code-like’s execution is
     paused, such as when emulating a generator, the scope needs to be
     exited and re-entered.

     The macros for 'event_types' are:

     Macro                                                  Event
                                                            
     -------------------------------------------------------------------------------------------------
                                                            
      -- C Macro: PY_MONITORING_EVENT_BRANCH                *note BRANCH: 45fe.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_CALL                  *note CALL: 1751.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_C_RAISE               *note C_RAISE: 45ff.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_C_RETURN              *note C_RETURN: 4600.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_EXCEPTION_HANDLED     *note EXCEPTION_HANDLED: 4601.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_INSTRUCTION           *note INSTRUCTION: 4602.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_JUMP                  *note JUMP: 4603.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_LINE                  *note LINE: 4604.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_RESUME             *note PY_RESUME: 4605.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_RETURN             *note PY_RETURN: 4606.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_START              *note PY_START: 4607.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_THROW              *note PY_THROW: 4608.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_UNWIND             *note PY_UNWIND: 4609.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_PY_YIELD              *note PY_YIELD: 460a.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_RAISE                 *note RAISE: 16f8.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_RERAISE               *note RERAISE: 460c.
                                                            
                                                            
      -- C Macro: PY_MONITORING_EVENT_STOP_ITERATION        *note STOP_ITERATION: 460b.
                                                            

 -- C Function: int PyMonitoring_ExitScope (void)

     Exit the last scope that was entered with
     ‘PyMonitoring_EnterScope()’.

 -- C Function: int PY_MONITORING_IS_INSTRUMENTED_EVENT (uint8_t ev)

     Return true if the event corresponding to the event ID 'ev' is a
     *note local event: 4610.

     Added in version 3.13.

     Deprecated since version 3.13.3: This function is *note soft
     deprecated: 209.


File: python.info,  Node: Installing Python modules,  Next: Python HOWTOs,  Prev: Python/C API Reference Manual,  Up: Top

8 Installing Python modules
***************************

As a popular open source development project, Python has an active
supporting community of contributors and users that also make their
software available for other Python developers to use under open-source
license terms.

This allows Python users to share and collaborate effectively,
benefiting from the solutions others have already created to common (and
sometimes even rare!)  problems, as well as potentially contributing
their own solutions to the common pool.

This guide covers the installation part of the process.  For a guide to
creating and sharing your own Python projects, refer to the Python
packaging user guide(1).

     Note: For corporate and other institutional users, be aware that
     many organisations have their own policies around using and
     contributing to open source software.  Please take such policies
     into account when making use of the distribution and installation
     tools provided with Python.

* Menu:

* Key terms::
* Basic usage::
* How do I …?::
* Common installation issues::

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/tutorials/packaging-projects/


File: python.info,  Node: Key terms,  Next: Basic usage,  Up: Installing Python modules

8.1 Key terms
=============

   * ‘pip’ is the preferred installer program.  It is included by
     default with the Python binary installers.

   * A 'virtual environment' is a semi-isolated Python environment that
     allows packages to be installed for use by a particular
     application, rather than being installed system wide.

   * ‘venv’ is the standard tool for creating virtual environments.  It
     defaults to installing ‘pip’ into all created virtual environments.

   * ‘virtualenv’ is a third-party alternative (and predecessor) to
     ‘venv’.

   * The Python Package Index (PyPI)(1) is a public repository of open
     source licensed packages made available for use by other Python
     users.

   * The Python Packaging Authority(2) is the group of developers and
     documentation authors responsible for the maintenance and evolution
     of the standard packaging tools and the associated metadata and
     file format standards.  They maintain a variety of tools,
     documentation, and issue trackers on GitHub(3).

Changed in version 3.5: The use of ‘venv’ is now recommended for
creating virtual environments.

See also
........

Python Packaging User Guide: Creating and using virtual environments(4)

   ---------- Footnotes ----------

   (1) https://pypi.org

   (2) https://www.pypa.io/

   (3) https://github.com/pypa

   (4) 
https://packaging.python.org/installing/#creating-virtual-environments


File: python.info,  Node: Basic usage,  Next: How do I …?,  Prev: Key terms,  Up: Installing Python modules

8.2 Basic usage
===============

The standard packaging tools are all designed to be used from the
command line.

The following command will install the latest version of a module and
its dependencies from PyPI:

     python -m pip install SomePackage

     Note: For POSIX users (including macOS and Linux users), the
     examples in this guide assume the use of a *note virtual
     environment: 1ea5.

     For Windows users, the examples in this guide assume that the
     option to adjust the system PATH environment variable was selected
     when installing Python.

It’s also possible to specify an exact or minimum version directly on
the command line.  When using comparator operators such as ‘>’, ‘<’ or
some other special character which get interpreted by shell, the package
name and the version should be enclosed within double quotes:

     python -m pip install SomePackage==1.0.4    # specific version
     python -m pip install "SomePackage>=1.0.4"  # minimum version

Normally, if a suitable module is already installed, attempting to
install it again will have no effect.  Upgrading existing modules must
be requested explicitly:

     python -m pip install --upgrade SomePackage

More information and resources regarding ‘pip’ and its capabilities can
be found in the Python Packaging User Guide(1).

Creation of virtual environments is done through the *note venv: 111.
module.  Installing packages into an active virtual environment uses the
commands shown above.

See also
........

Python Packaging User Guide: Installing Python Distribution Packages(2)

   ---------- Footnotes ----------

   (1) https://packaging.python.org

   (2) https://packaging.python.org/installing/


File: python.info,  Node: How do I …?,  Next: Common installation issues,  Prev: Basic usage,  Up: Installing Python modules

8.3 How do I …?
===============

These are quick answers or links for some common tasks.

* Menu:

* … install packages just for the current user?::
* … install scientific Python packages?::
* … work with multiple versions of Python installed in parallel?::


File: python.info,  Node: … install packages just for the current user?,  Next: … install scientific Python packages?,  Up: How do I …?

8.3.1 … install packages just for the current user?
---------------------------------------------------

Passing the ‘--user’ option to ‘python -m pip install’ will install a
package just for the current user, rather than for all users of the
system.


File: python.info,  Node: … install scientific Python packages?,  Next: … work with multiple versions of Python installed in parallel?,  Prev: … install packages just for the current user?,  Up: How do I …?

8.3.2 … install scientific Python packages?
-------------------------------------------

A number of scientific Python packages have complex binary dependencies,
and aren’t currently easy to install using ‘pip’ directly.  It will
often be easier for users to install these packages by other means(1)
rather than attempting to install them with ‘pip’.

See also
........

Python Packaging User Guide: Installing Scientific Packages(2)

   ---------- Footnotes ----------

   (1) https://packaging.python.org/science/

   (2) https://packaging.python.org/science/


File: python.info,  Node: … work with multiple versions of Python installed in parallel?,  Prev: … install scientific Python packages?,  Up: How do I …?

8.3.3 … work with multiple versions of Python installed in parallel?
--------------------------------------------------------------------

On Linux, macOS, and other POSIX systems, use the versioned Python
commands in combination with the ‘-m’ switch to run the appropriate copy
of ‘pip’:

     python3    -m pip install SomePackage  # default Python 3
     python3.14 -m pip install SomePackage  # specifically Python 3.14

Appropriately versioned ‘pip’ commands may also be available.

On Windows, use the ‘py’ Python launcher in combination with the ‘-m’
switch:

     py -3    -m pip install SomePackage  # default Python 3
     py -3.14 -m pip install SomePackage  # specifically Python 3.14


File: python.info,  Node: Common installation issues,  Prev: How do I …?,  Up: Installing Python modules

8.4 Common installation issues
==============================

* Menu:

* Installing into the system Python on Linux::
* Pip not installed::
* Installing binary extensions::


File: python.info,  Node: Installing into the system Python on Linux,  Next: Pip not installed,  Up: Common installation issues

8.4.1 Installing into the system Python on Linux
------------------------------------------------

On Linux systems, a Python installation will typically be included as
part of the distribution.  Installing into this Python installation
requires root access to the system, and may interfere with the operation
of the system package manager and other components of the system if a
component is unexpectedly upgraded using ‘pip’.

On such systems, it is often better to use a virtual environment or a
per-user installation when installing packages with ‘pip’.


File: python.info,  Node: Pip not installed,  Next: Installing binary extensions,  Prev: Installing into the system Python on Linux,  Up: Common installation issues

8.4.2 Pip not installed
-----------------------

It is possible that ‘pip’ does not get installed by default.  One
potential fix is:

     python -m ensurepip --default-pip

There are also additional resources for installing pip(1).

   ---------- Footnotes ----------

   (1) 
https://packaging.python.org/en/latest/tutorials/installing-packages/#ensure-pip-setuptools-and-wheel-are-up-to-date


File: python.info,  Node: Installing binary extensions,  Prev: Pip not installed,  Up: Common installation issues

8.4.3 Installing binary extensions
----------------------------------

Python once relied heavily on source-based distribution, with end users
being expected to compile extension modules from source as part of the
installation process.

With the introduction of the binary wheel format, and the ability to
publish wheels through PyPI, this problem is diminishing, as users are
more regularly able to install pre-built extensions rather than needing
to build them themselves.

Some of the solutions for installing scientific software(1) that are not
yet available as pre-built wheel files may also help with obtaining
other binary extensions without needing to build them locally.

See also
........

Python Packaging User Guide: Binary Extensions(2)

   ---------- Footnotes ----------

   (1) https://packaging.python.org/science/

   (2) https://packaging.python.org/extensions/


File: python.info,  Node: Python HOWTOs,  Next: Python Frequently Asked Questions,  Prev: Installing Python modules,  Up: Top

9 Python HOWTOs
***************

Python HOWTOs are documents that cover a specific topic in-depth.
Modeled on the Linux Documentation Project’s HOWTO collection, this
collection is an effort to foster documentation that’s more detailed
than the Python Library Reference.

* Menu:

* A Conceptual Overview of asyncio::
* Porting Extension Modules to Python 3::
* Curses Programming with Python::
* Descriptor Guide::
* Debugging C API extensions and CPython Internals with GDB::
* Enum HOWTO::
* Functional Programming HOWTO::
* Logging HOWTO::
* Logging Cookbook::
* Regular expression HOWTO::
* Socket Programming HOWTO::
* Sorting Techniques::
* Unicode HOWTO::
* HOWTO Fetch Internet Resources Using The urllib Package::
* An introduction to the ipaddress module::
* Instrumenting CPython with DTrace and SystemTap::
* Python support for the Linux perf profiler::
* Annotations Best Practices::
* Isolating Extension Modules::
* timer file descriptor HOWTO::
* The Python 2.3 Method Resolution Order: The Python 2 3 Method Resolution Order.
* Python experimental support for free threading::
* C API Extension Support for Free Threading::


File: python.info,  Node: A Conceptual Overview of asyncio,  Next: Porting Extension Modules to Python 3,  Up: Python HOWTOs

9.1 A Conceptual Overview of ‘asyncio’
======================================

This *note HOWTO: 5322. article seeks to help you build a sturdy mental
model of how *note asyncio: a. fundamentally works, helping you
understand the how and why behind the recommended patterns.

You might be curious about some key ‘asyncio’ concepts.  By the end of
this article, you’ll be able to comfortably answer these questions:

   - What’s happening behind the scenes when an object is awaited?

   - How does ‘asyncio’ differentiate between a task which doesn’t need
     CPU time (such as a network request or file read) as opposed to a
     task that does (such as computing n-factorial)?

   - How to write an asynchronous variant of an operation, such as an
     async sleep or database request.

See also
........

   * The guide(1) that inspired this HOWTO article, by Alexander Nordin.

   * This in-depth YouTube tutorial series(2) on ‘asyncio’ created by
     Python core team member, Łukasz Langa.

   * 500 Lines or Less: A Web Crawler With asyncio Coroutines(3) by A.
     Jesse Jiryu Davis and Guido van Rossum.

* Menu:

* A conceptual overview part 1; the high-level: A conceptual overview part 1 the high-level.
* A conceptual overview part 2; the nuts and bolts: A conceptual overview part 2 the nuts and bolts.

   ---------- Footnotes ----------

   (1) 
https://github.com/anordin95/a-conceptual-overview-of-asyncio/tree/main

   (2) 
https://www.youtube.com/watch?v=Xbl7XjFYsN4&list=PLhNSoGM2ik6SIkVGXWBwerucXjgP1rHmB

   (3) 
https://aosabook.org/en/500L/a-web-crawler-with-asyncio-coroutines.html


File: python.info,  Node: A conceptual overview part 1 the high-level,  Next: A conceptual overview part 2 the nuts and bolts,  Up: A Conceptual Overview of asyncio

9.1.1 A conceptual overview part 1: the high-level
--------------------------------------------------

In part 1, we’ll cover the main, high-level building blocks of
‘asyncio’: the event loop, coroutine functions, coroutine objects,
tasks, and ‘await’.

* Menu:

* Event Loop::
* Asynchronous functions and coroutines::
* Tasks: Tasks<2>.
* await::


File: python.info,  Node: Event Loop,  Next: Asynchronous functions and coroutines,  Up: A conceptual overview part 1 the high-level

9.1.1.1 Event Loop
..................

Everything in ‘asyncio’ happens relative to the event loop.  It’s the
star of the show.  It’s like an orchestra conductor.  It’s behind the
scenes managing resources.  Some power is explicitly granted to it, but
a lot of its ability to get things done comes from the respect and
cooperation of its worker bees.

In more technical terms, the event loop contains a collection of jobs to
be run.  Some jobs are added directly by you, and some indirectly by
‘asyncio’.  The event loop takes a job from its backlog of work and
invokes it (or “gives it control”), similar to calling a function, and
then that job runs.  Once it pauses or completes, it returns control to
the event loop.  The event loop will then select another job from its
pool and invoke it.  You can 'roughly' think of the collection of jobs
as a queue: jobs are added and then processed one at a time, generally
(but not always) in order.  This process repeats indefinitely, with the
event loop cycling endlessly onwards.  If there are no more jobs pending
execution, the event loop is smart enough to rest and avoid needlessly
wasting CPU cycles, and will come back when there’s more work to be
done.

Effective execution relies on jobs sharing well and cooperating; a
greedy job could hog control and leave the other jobs to starve,
rendering the overall event loop approach rather useless.

     import asyncio

     # This creates an event loop and indefinitely cycles through
     # its collection of jobs.
     event_loop = asyncio.new_event_loop()
     event_loop.run_forever()


File: python.info,  Node: Asynchronous functions and coroutines,  Next: Tasks<2>,  Prev: Event Loop,  Up: A conceptual overview part 1 the high-level

9.1.1.2 Asynchronous functions and coroutines
.............................................

This is a basic, boring Python function:

     def hello_printer():
         print(
             "Hi, I am a lowly, simple printer, though I have all I "
             "need in life -- \nfresh paper and my dearly beloved octopus "
             "partner in crime."
         )

Calling a regular function invokes its logic or body:

     >>> hello_printer()
     Hi, I am a lowly, simple printer, though I have all I need in life --
     fresh paper and my dearly beloved octopus partner in crime.

The *note async def: 5d4, as opposed to just a plain ‘def’, makes this
an asynchronous function (or “coroutine function”).  Calling it creates
and returns a *note coroutine: 348e. object.

     async def loudmouth_penguin(magic_number: int):
         print(
          "I am a super special talking penguin. Far cooler than that printer. "
          f"By the way, my lucky number is: {magic_number}."
         )

Calling the async function, ‘loudmouth_penguin’, does not execute the
print statement; instead, it creates a coroutine object:

     >>> loudmouth_penguin(magic_number=3)
     <coroutine object loudmouth_penguin at 0x104ed2740>

The terms “coroutine function” and “coroutine object” are often
conflated as coroutine.  That can be confusing!  In this article,
coroutine specifically refers to a coroutine object, or more precisely,
an instance of *note types.CoroutineType: ebd. (native coroutine).  Note
that coroutines can also exist as instances of *note
collections.abc.Coroutine: e0d. – a distinction that matters for type
checking.

A coroutine represents the function’s body or logic.  A coroutine has to
be explicitly started; again, merely creating the coroutine does not
start it.  Notably, the coroutine can be paused and resumed at various
points within the function’s body.  That pausing and resuming ability is
what allows for asynchronous behavior!

Coroutines and coroutine functions were built by leveraging the
functionality of *note generators: bff. and *note generator functions:
109f.  Recall, a generator function is a function that *note yield:
9d8.s, like this one:

     def get_random_number():
         # This would be a bad random number generator!
         print("Hi")
         yield 1
         print("Hello")
         yield 7
         print("Howdy")
         yield 4
         ...

Similar to a coroutine function, calling a generator function does not
run it.  Instead, it creates a generator object:

     >>> get_random_number()
     <generator object get_random_number at 0x1048671c0>

You can proceed to the next ‘yield’ of a generator by using the built-in
function *note next(): 7dc.  In other words, the generator runs, then
pauses.  For example:

     >>> generator = get_random_number()
     >>> next(generator)
     Hi
     1
     >>> next(generator)
     Hello
     7


File: python.info,  Node: Tasks<2>,  Next: await,  Prev: Asynchronous functions and coroutines,  Up: A conceptual overview part 1 the high-level

9.1.1.3 Tasks
.............

Roughly speaking, *note tasks: 34c0. are coroutines (not coroutine
functions) tied to an event loop.  A task also maintains a list of
callback functions whose importance will become clear in a moment when
we discuss *note await: 1b9.  The recommended way to create tasks is via
*note asyncio.create_task(): 1bf.

Creating a task automatically schedules it for execution (by adding a
callback to run it in the event loop’s to-do list, that is, collection
of jobs).

‘asyncio’ automatically associates tasks with the event loop for you.
This automatic association was purposely designed into ‘asyncio’ for the
sake of simplicity.  Without it, you’d have to keep track of the event
loop object and pass it to any coroutine function that wants to create
tasks, adding redundant clutter to your code.

     coroutine = loudmouth_penguin(magic_number=5)
     # This creates a Task object and schedules its execution via the event loop.
     task = asyncio.create_task(coroutine)

Earlier, we manually created the event loop and set it to run forever.
In practice, it’s recommended to use (and common to see) *note
asyncio.run(): 47f, which takes care of managing the event loop and
ensuring the provided coroutine finishes before advancing.  For example,
many async programs follow this setup:

     import asyncio

     async def main():
         # Perform all sorts of wacky, wild asynchronous things...
         ...

     if __name__ == "__main__":
         asyncio.run(main())
         # The program will not reach the following print statement until the
         # coroutine main() finishes.
         print("coroutine main() is done!")

It’s important to be aware that the task itself is not added to the
event loop, only a callback to the task is.  This matters if the task
object you created is garbage collected before it’s called by the event
loop.  For example, consider this program:

     async def hello():
         print("hello!")

     async def main():
         asyncio.create_task(hello())
         # Other asynchronous instructions which run for a while
         # and cede control to the event loop...
         ...

     asyncio.run(main())

Because there’s no reference to the task object created on line 5, it
'might' be garbage collected before the event loop invokes it.  Later
instructions in the coroutine ‘main()’ hand control back to the event
loop so it can invoke other jobs.  When the event loop eventually tries
to run the task, it might fail and discover the task object does not
exist!  This can also happen even if a coroutine keeps a reference to a
task but completes before that task finishes.  When the coroutine exits,
local variables go out of scope and may be subject to garbage
collection.  In practice, ‘asyncio’ and Python’s garbage collector work
pretty hard to ensure this sort of thing doesn’t happen.  But that’s no
reason to be reckless!


File: python.info,  Node: await,  Prev: Tasks<2>,  Up: A conceptual overview part 1 the high-level

9.1.1.4 await
.............

*note await: 1b9. is a Python keyword that’s commonly used in one of two
different ways:

     await task
     await coroutine

In a crucial way, the behavior of ‘await’ depends on the type of object
being awaited.

Awaiting a task will cede control from the current task or coroutine to
the event loop.  In the process of relinquishing control, a few
important things happen.  We’ll use the following code example to
illustrate:

     async def plant_a_tree():
         dig_the_hole_task = asyncio.create_task(dig_the_hole())
         await dig_the_hole_task

         # Other instructions associated with planting a tree.
         ...

In this example, imagine the event loop has passed control to the start
of the coroutine ‘plant_a_tree()’.  As seen above, the coroutine creates
a task and then awaits it.  The ‘await dig_the_hole_task’ instruction
adds a callback (which will resume ‘plant_a_tree()’) to the
‘dig_the_hole_task’ object’s list of callbacks.  And then, the
instruction cedes control to the event loop.  Some time later, the event
loop will pass control to ‘dig_the_hole_task’ and the task will finish
whatever it needs to do.  Once the task finishes, it will add its
various callbacks to the event loop, in this case, a call to resume
‘plant_a_tree()’.

Generally speaking, when the awaited task finishes
(‘dig_the_hole_task’), the original task or coroutine (‘plant_a_tree()’)
is added back to the event loop’s to-do list to be resumed.

This is a basic, yet reliable mental model.  In practice, the control
handoffs are slightly more complex, but not by much.  In part 2, we’ll
walk through the details that make this possible.

'Unlike tasks, awaiting a coroutine does not hand control back to the
event loop!'  Wrapping a coroutine in a task first, then awaiting that
would cede control.  The behavior of ‘await coroutine’ is effectively
the same as invoking a regular, synchronous Python function.  Consider
this program:

     import asyncio

     async def coro_a():
        print("I am coro_a(). Hi!")

     async def coro_b():
        print("I am coro_b(). I sure hope no one hogs the event loop...")

     async def main():
        task_b = asyncio.create_task(coro_b())
        num_repeats = 3
        for _ in range(num_repeats):
           await coro_a()
        await task_b

     asyncio.run(main())

The first statement in the coroutine ‘main()’ creates ‘task_b’ and
schedules it for execution via the event loop.  Then, ‘coro_a()’ is
repeatedly awaited.  Control never cedes to the event loop, which is why
we see the output of all three ‘coro_a()’ invocations before
‘coro_b()’’s output:

     I am coro_a(). Hi!
     I am coro_a(). Hi!
     I am coro_a(). Hi!
     I am coro_b(). I sure hope no one hogs the event loop...

If we change ‘await coro_a()’ to ‘await asyncio.create_task(coro_a())’,
the behavior changes.  The coroutine ‘main()’ cedes control to the event
loop with that statement.  The event loop then proceeds through its
backlog of work, calling ‘task_b’ and then the task which wraps
‘coro_a()’ before resuming the coroutine ‘main()’.

     I am coro_b(). I sure hope no one hogs the event loop...
     I am coro_a(). Hi!
     I am coro_a(). Hi!
     I am coro_a(). Hi!

This behavior of ‘await coroutine’ can trip a lot of people up!  That
example highlights how using only ‘await coroutine’ could
unintentionally hog control from other tasks and effectively stall the
event loop.  *note asyncio.run(): 47f. can help you detect such
occurrences via the ‘debug=True’ flag, which enables *note debug mode:
1ef2.  Among other things, it will log any coroutines that monopolize
execution for 100ms or longer.

The design intentionally trades off some conceptual clarity around usage
of ‘await’ for improved performance.  Each time a task is awaited,
control needs to be passed all the way up the call stack to the event
loop.  That might sound minor, but in a large program with many ‘await’
statements and a deep call stack, that overhead can add up to a
meaningful performance drag.


File: python.info,  Node: A conceptual overview part 2 the nuts and bolts,  Prev: A conceptual overview part 1 the high-level,  Up: A Conceptual Overview of asyncio

9.1.2 A conceptual overview part 2: the nuts and bolts
------------------------------------------------------

Part 2 goes into detail on the mechanisms ‘asyncio’ uses to manage
control flow.  This is where the magic happens.  You’ll come away from
this section knowing what ‘await’ does behind the scenes and how to make
your own asynchronous operators.

* Menu:

* The inner workings of coroutines::
* Futures: Futures<2>.
* A homemade asyncio.sleep: A homemade asyncio sleep.


File: python.info,  Node: The inner workings of coroutines,  Next: Futures<2>,  Up: A conceptual overview part 2 the nuts and bolts

9.1.2.1 The inner workings of coroutines
........................................

‘asyncio’ leverages four components to pass around control.

*note coroutine.send(arg): 217d. is the method used to start or resume a
coroutine.  If the coroutine was paused and is now being resumed, the
argument ‘arg’ will be sent in as the return value of the ‘yield’
statement which originally paused it.  If the coroutine is being used
for the first time (as opposed to being resumed), ‘arg’ must be ‘None’.

     class Rock:
         def __await__(self):
             value_sent_in = yield 7
             print(f"Rock.__await__ resuming with value: {value_sent_in}.")
             return value_sent_in

     async def main():
         print("Beginning coroutine main().")
         rock = Rock()
         print("Awaiting rock...")
         value_from_rock = await rock
         print(f"Coroutine received value: {value_from_rock} from rock.")
         return 23

     coroutine = main()
     intermediate_result = coroutine.send(None)
     print(f"Coroutine paused and returned intermediate value: {intermediate_result}.")

     print(f"Resuming coroutine and sending in value: 42.")
     try:
         coroutine.send(42)
     except StopIteration as e:
         returned_value = e.value
     print(f"Coroutine main() finished and provided value: {returned_value}.")

*note yield: 21ef, as usual, pauses execution and returns control to the
caller.  In the example above, the ‘yield’, on line 3, is called by ‘...
= await rock’ on line 11.  More broadly speaking, ‘await’ calls the
*note __await__(): da3. method of the given object.  ‘await’ also does
one more very special thing: it propagates (or “passes along”) any
‘yield’s it receives up the call chain.  In this case, that’s back to
‘... = coroutine.send(None)’ on line 16.

The coroutine is resumed via the ‘coroutine.send(42)’ call on line 21.
The coroutine picks back up from where it ‘yield’ed (or paused) on line
3 and executes the remaining statements in its body.  When a coroutine
finishes, it raises a *note StopIteration: c1b. exception with the
return value attached in the *note value: 217a. attribute.

That snippet produces this output:

     Beginning coroutine main().
     Awaiting rock...
     Coroutine paused and returned intermediate value: 7.
     Resuming coroutine and sending in value: 42.
     Rock.__await__ resuming with value: 42.
     Coroutine received value: 42 from rock.
     Coroutine main() finished and provided value: 23.

It’s worth pausing for a moment here and making sure you followed the
various ways that control flow and values were passed.  A lot of
important ideas were covered and it’s worth ensuring your understanding
is firm.

The only way to yield (or effectively cede control) from a coroutine is
to ‘await’ an object that ‘yield’s in its ‘__await__’ method.  That
might sound odd to you.  You might be thinking:

     1.  What about a ‘yield’ directly within the coroutine function?
     The coroutine function becomes an *note async generator function:
     21f3, a different beast entirely.

     2.  What about a *note yield from: 21ef. within the coroutine
     function to a (plain) generator?  That causes the error:
     ‘SyntaxError: yield from not allowed in a coroutine.’ This was
     intentionally designed for the sake of simplicity – mandating only
     one way of using coroutines.  Initially ‘yield’ was barred as well,
     but was re-accepted to allow for async generators.  Despite that,
     ‘yield from’ and ‘await’ effectively do the same thing.


File: python.info,  Node: Futures<2>,  Next: A homemade asyncio sleep,  Prev: The inner workings of coroutines,  Up: A conceptual overview part 2 the nuts and bolts

9.1.2.2 Futures
...............

A *note future: 3594. is an object meant to represent a computation’s
status and result.  The term is a nod to the idea of something still to
come or not yet happened, and the object is a way to keep an eye on that
something.

A future has a few important attributes.  One is its state, which can be
either “pending”, “cancelled”, or “done”.  Another is its result, which
is set when the state transitions to done.  Unlike a coroutine, a future
does not represent the actual computation to be done; instead, it
represents the status and result of that computation, kind of like a
status light (red, yellow, or green) or indicator.

*note asyncio.Task: 1be. subclasses *note asyncio.Future: bec. in order
to gain these various capabilities.  The prior section said tasks store
a list of callbacks, which wasn’t entirely accurate.  It’s actually the
‘Future’ class that implements this logic, which ‘Task’ inherits.

Futures may also be used directly (not via tasks).  Tasks mark
themselves as done when their coroutine is complete.  Futures are much
more versatile and will be marked as done when you say so.  In this way,
they’re the flexible interface for you to make your own conditions for
waiting and resuming.


File: python.info,  Node: A homemade asyncio sleep,  Prev: Futures<2>,  Up: A conceptual overview part 2 the nuts and bolts

9.1.2.3 A homemade asyncio.sleep
................................

We’ll go through an example of how you could leverage a future to create
your own variant of asynchronous sleep (‘async_sleep’) which mimics
*note asyncio.sleep(): a7e.

This snippet registers a few tasks with the event loop and then awaits
the task created by ‘asyncio.create_task’, which wraps the
‘async_sleep(3)’ coroutine.  We want that task to finish only after
three seconds have elapsed, but without preventing other tasks from
running.

     async def other_work():
         print("I like work. Work work.")

     async def main():
         # Add a few other tasks to the event loop, so there's something
         # to do while asynchronously sleeping.
         work_tasks = [
             asyncio.create_task(other_work()),
             asyncio.create_task(other_work()),
             asyncio.create_task(other_work())
         ]
         print(
             "Beginning asynchronous sleep at time: "
             f"{datetime.datetime.now().strftime("%H:%M:%S")}."
         )
         await asyncio.create_task(async_sleep(3))
         print(
             "Done asynchronous sleep at time: "
             f"{datetime.datetime.now().strftime("%H:%M:%S")}."
         )
         # asyncio.gather effectively awaits each task in the collection.
         await asyncio.gather(*work_tasks)

Below, we use a future to enable custom control over when that task will
be marked as done.  If *note future.set_result(): 34c3. (the method
responsible for marking that future as done) is never called, then this
task will never finish.  We’ve also enlisted the help of another task,
which we’ll see in a moment, that will monitor how much time has elapsed
and, accordingly, call ‘future.set_result()’.

     async def async_sleep(seconds: float):
         future = asyncio.Future()
         time_to_wake = time.time() + seconds
         # Add the watcher-task to the event loop.
         watcher_task = asyncio.create_task(_sleep_watcher(future, time_to_wake))
         # Block until the future is marked as done.
         await future

Below, we use a rather bare ‘YieldToEventLoop()’ object to ‘yield’ from
its ‘__await__’ method, ceding control to the event loop.  This is
effectively the same as calling ‘asyncio.sleep(0)’, but this approach
offers more clarity, not to mention it’s somewhat cheating to use
‘asyncio.sleep’ when showcasing how to implement it!

As usual, the event loop cycles through its tasks, giving them control
and receiving control back when they pause or finish.  The
‘watcher_task’, which runs the coroutine ‘_sleep_watcher(...)’, will be
invoked once per full cycle of the event loop.  On each resumption,
it’ll check the time and if not enough has elapsed, then it’ll pause
once again and hand control back to the event loop.  Once enough time
has elapsed, ‘_sleep_watcher(...)’ marks the future as done and
completes by exiting its infinite ‘while’ loop.  Given this helper task
is only invoked once per cycle of the event loop, you’d be correct to
note that this asynchronous sleep will sleep 'at least' three seconds,
rather than exactly three seconds.  Note this is also true of
‘asyncio.sleep’.

     class YieldToEventLoop:
         def __await__(self):
             yield

     async def _sleep_watcher(future, time_to_wake):
         while True:
             if time.time() >= time_to_wake:
                 # This marks the future as done.
                 future.set_result(None)
                 break
             else:
                 await YieldToEventLoop()

Here is the full program’s output:

     $ python custom-async-sleep.py
     Beginning asynchronous sleep at time: 14:52:22.
     I like work. Work work.
     I like work. Work work.
     I like work. Work work.
     Done asynchronous sleep at time: 14:52:25.

You might feel this implementation of asynchronous sleep was
unnecessarily convoluted.  And, well, it was.  The example was meant to
showcase the versatility of futures with a simple example that could be
mimicked for more complex needs.  For reference, you could implement it
without futures, like so:

     async def simpler_async_sleep(seconds):
         time_to_wake = time.time() + seconds
         while True:
             if time.time() >= time_to_wake:
                 return
             else:
                 await YieldToEventLoop()

But that’s all for now.  Hopefully you’re ready to more confidently dive
into some async programming or check out advanced topics in the *note
rest of the documentation: a.


File: python.info,  Node: Porting Extension Modules to Python 3,  Next: Curses Programming with Python,  Prev: A Conceptual Overview of asyncio,  Up: Python HOWTOs

9.2 Porting Extension Modules to Python 3
=========================================

We recommend the following resources for porting extension modules to
Python 3:

   * The Migrating C extensions(1) chapter from 'Supporting Python 3: An
     in-depth guide', a book on moving from Python 2 to Python 3 in
     general, guides the reader through porting an extension module.

   * The Porting guide(2) from the 'py3c' project provides opinionated
     suggestions with supporting code.

   * *note Recommended third party tools: 4b58. offer abstractions over
     the Python’s C API. Extensions generally need to be re-written to
     use one of them, but the library then handles differences between
     various Python versions and implementations.

   ---------- Footnotes ----------

   (1) http://python3porting.com/cextensions.html

   (2) https://py3c.readthedocs.io/en/latest/guide.html


File: python.info,  Node: Curses Programming with Python,  Next: Descriptor Guide,  Prev: Porting Extension Modules to Python 3,  Up: Python HOWTOs

9.3 Curses Programming with Python
==================================


Author: A.M. Kuchling, Eric S. Raymond


Release: 2.04

Abstract
........

This document describes how to use the *note curses: 2b. extension
module to control text-mode displays.

* Menu:

* What is curses?::
* Starting and ending a curses application::
* Windows and Pads::
* Displaying Text::
* User Input::
* For More Information::


File: python.info,  Node: What is curses?,  Next: Starting and ending a curses application,  Up: Curses Programming with Python

9.3.1 What is curses?
---------------------

The curses library supplies a terminal-independent screen-painting and
keyboard-handling facility for text-based terminals; such terminals
include VT100s, the Linux console, and the simulated terminal provided
by various programs.  Display terminals support various control codes to
perform common operations such as moving the cursor, scrolling the
screen, and erasing areas.  Different terminals use widely differing
codes, and often have their own minor quirks.

In a world of graphical displays, one might ask “why bother”?  It’s true
that character-cell display terminals are an obsolete technology, but
there are niches in which being able to do fancy things with them are
still valuable.  One niche is on small-footprint or embedded Unixes that
don’t run an X server.  Another is tools such as OS installers and
kernel configurators that may have to run before any graphical support
is available.

The curses library provides fairly basic functionality, providing the
programmer with an abstraction of a display containing multiple
non-overlapping windows of text.  The contents of a window can be
changed in various ways—adding text, erasing it, changing its
appearance—and the curses library will figure out what control codes
need to be sent to the terminal to produce the right output.  curses
doesn’t provide many user-interface concepts such as buttons,
checkboxes, or dialogs; if you need such features, consider a user
interface library such as Urwid(1).

The curses library was originally written for BSD Unix; the later System
V versions of Unix from AT&T added many enhancements and new functions.
BSD curses is no longer maintained, having been replaced by ncurses,
which is an open-source implementation of the AT&T interface.  If you’re
using an open-source Unix such as Linux or FreeBSD, your system almost
certainly uses ncurses.  Since most current commercial Unix versions are
based on System V code, all the functions described here will probably
be available.  The older versions of curses carried by some proprietary
Unixes may not support everything, though.

The Windows version of Python doesn’t include the *note curses: 2b.
module.  A ported version called UniCurses(2) is available.

* Menu:

* The Python curses module::

   ---------- Footnotes ----------

   (1) https://pypi.org/project/Urwid/

   (2) https://pypi.org/project/UniCurses/


File: python.info,  Node: The Python curses module,  Up: What is curses?

9.3.1.1 The Python curses module
................................

The Python module is a fairly simple wrapper over the C functions
provided by curses; if you’re already familiar with curses programming
in C, it’s really easy to transfer that knowledge to Python.  The
biggest difference is that the Python interface makes things simpler by
merging different C functions such as ‘addstr()’, ‘mvaddstr()’, and
‘mvwaddstr()’ into a single *note addstr(): 316b. method.  You’ll see
this covered in more detail later.

This HOWTO is an introduction to writing text-mode programs with curses
and Python.  It doesn’t attempt to be a complete guide to the curses
API; for that, see the Python library guide’s section on ncurses, and
the C manual pages for ncurses.  It will, however, give you the basic
ideas.


File: python.info,  Node: Starting and ending a curses application,  Next: Windows and Pads,  Prev: What is curses?,  Up: Curses Programming with Python

9.3.2 Starting and ending a curses application
----------------------------------------------

Before doing anything, curses must be initialized.  This is done by
calling the *note initscr(): 16a7. function, which will determine the
terminal type, send any required setup codes to the terminal, and create
various internal data structures.  If successful, ‘initscr()’ returns a
window object representing the entire screen; this is usually called
‘stdscr’ after the name of the corresponding C variable.

     import curses
     stdscr = curses.initscr()

Usually curses applications turn off automatic echoing of keys to the
screen, in order to be able to read keys and only display them under
certain circumstances.  This requires calling the *note noecho(): 3194.
function.

     curses.noecho()

Applications will also commonly need to react to keys instantly, without
requiring the Enter key to be pressed; this is called cbreak mode, as
opposed to the usual buffered input mode.

     curses.cbreak()

Terminals usually return special keys, such as the cursor keys or
navigation keys such as Page Up and Home, as a multibyte escape
sequence.  While you could write your application to expect such
sequences and process them accordingly, curses can do it for you,
returning a special value such as *note curses.KEY_LEFT: 320d.  To get
curses to do the job, you’ll have to enable keypad mode.

     stdscr.keypad(True)

Terminating a curses application is much easier than starting one.
You’ll need to call:

     curses.nocbreak()
     stdscr.keypad(False)
     curses.echo()

to reverse the curses-friendly terminal settings.  Then call the *note
endwin(): 316e. function to restore the terminal to its original
operating mode.

     curses.endwin()

A common problem when debugging a curses application is to get your
terminal messed up when the application dies without restoring the
terminal to its previous state.  In Python this commonly happens when
your code is buggy and raises an uncaught exception.  Keys are no longer
echoed to the screen when you type them, for example, which makes using
the shell difficult.

In Python you can avoid these complications and make debugging much
easier by importing the *note curses.wrapper(): a8f. function and using
it like this:

     from curses import wrapper

     def main(stdscr):
         # Clear screen
         stdscr.clear()

         # This raises ZeroDivisionError when i == 10.
         for i in range(0, 11):
             v = i-10
             stdscr.addstr(i, 0, '10 divided by {} is {}'.format(v, 10/v))

             stdscr.refresh()
             stdscr.getkey()

     wrapper(main)

The *note wrapper(): a8f. function takes a callable object and does the
initializations described above, also initializing colors if color
support is present.  ‘wrapper()’ then runs your provided callable.  Once
the callable returns, ‘wrapper()’ will restore the original state of the
terminal.  The callable is called inside a *note try: 6ec.…*note except:
18b. that catches exceptions, restores the state of the terminal, and
then re-raises the exception.  Therefore your terminal won’t be left in
a funny state on exception and you’ll be able to read the exception’s
message and traceback.


File: python.info,  Node: Windows and Pads,  Next: Displaying Text,  Prev: Starting and ending a curses application,  Up: Curses Programming with Python

9.3.3 Windows and Pads
----------------------

Windows are the basic abstraction in curses.  A window object represents
a rectangular area of the screen, and supports methods to display text,
erase it, allow the user to input strings, and so forth.

The ‘stdscr’ object returned by the *note initscr(): 16a7. function is a
window object that covers the entire screen.  Many programs may need
only this single window, but you might wish to divide the screen into
smaller windows, in order to redraw or clear them separately.  The *note
newwin(): 3192. function creates a new window of a given size, returning
the new window object.

     begin_x = 20; begin_y = 7
     height = 5; width = 40
     win = curses.newwin(height, width, begin_y, begin_x)

Note that the coordinate system used in curses is unusual.  Coordinates
are always passed in the order 'y,x', and the top-left corner of a
window is coordinate (0,0).  This breaks the normal convention for
handling coordinates where the 'x' coordinate comes first.  This is an
unfortunate difference from most other computer applications, but it’s
been part of curses since it was first written, and it’s too late to
change things now.

Your application can determine the size of the screen by using the *note
curses.LINES: e1d. and *note curses.COLS: e1e. variables to obtain the
'y' and 'x' sizes.  Legal coordinates will then extend from ‘(0,0)’ to
‘(curses.LINES - 1, curses.COLS - 1)’.

When you call a method to display or erase text, the effect doesn’t
immediately show up on the display.  Instead you must call the *note
refresh(): 316c. method of window objects to update the screen.

This is because curses was originally written with slow 300-baud
terminal connections in mind; with these terminals, minimizing the time
required to redraw the screen was very important.  Instead curses
accumulates changes to the screen and displays them in the most
efficient manner when you call ‘refresh()’.  For example, if your
program displays some text in a window and then clears the window,
there’s no need to send the original text because they’re never visible.

In practice, explicitly telling curses to redraw a window doesn’t really
complicate programming with curses much.  Most programs go into a flurry
of activity, and then pause waiting for a keypress or some other action
on the part of the user.  All you have to do is to be sure that the
screen has been redrawn before pausing to wait for user input, by first
calling ‘stdscr.refresh()’ or the ‘refresh()’ method of some other
relevant window.

A pad is a special case of a window; it can be larger than the actual
display screen, and only a portion of the pad displayed at a time.
Creating a pad requires the pad’s height and width, while refreshing a
pad requires giving the coordinates of the on-screen area where a
subsection of the pad will be displayed.

     pad = curses.newpad(100, 100)
     # These loops fill the pad with letters; addch() is
     # explained in the next section
     for y in range(0, 99):
         for x in range(0, 99):
             pad.addch(y,x, ord('a') + (x*x+y*y) % 26)

     # Displays a section of the pad in the middle of the screen.
     # (0,0) : coordinate of upper-left corner of pad area to display.
     # (5,5) : coordinate of upper-left corner of window area to be filled
     #         with pad content.
     # (20, 75) : coordinate of lower-right corner of window area to be
     #          : filled with pad content.
     pad.refresh( 0,0, 5,5, 20,75)

The ‘refresh()’ call displays a section of the pad in the rectangle
extending from coordinate (5,5) to coordinate (20,75) on the screen; the
upper left corner of the displayed section is coordinate (0,0) on the
pad.  Beyond that difference, pads are exactly like ordinary windows and
support the same methods.

If you have multiple windows and pads on screen there is a more
efficient way to update the screen and prevent annoying screen flicker
as each part of the screen gets updated.  ‘refresh()’ actually does two
things:

  1. Calls the *note noutrefresh(): 316a. method of each window to
     update an underlying data structure representing the desired state
     of the screen.

  2. Calls the function *note doupdate(): 3169. function to change the
     physical screen to match the desired state recorded in the data
     structure.

Instead you can call ‘noutrefresh()’ on a number of windows to update
the data structure, and then call ‘doupdate()’ to update the screen.


File: python.info,  Node: Displaying Text,  Next: User Input,  Prev: Windows and Pads,  Up: Curses Programming with Python

9.3.4 Displaying Text
---------------------

From a C programmer’s point of view, curses may sometimes look like a
twisty maze of functions, all subtly different.  For example, ‘addstr()’
displays a string at the current cursor location in the ‘stdscr’ window,
while ‘mvaddstr()’ moves to a given y,x coordinate first before
displaying the string.  ‘waddstr()’ is just like ‘addstr()’, but allows
specifying a window to use instead of using ‘stdscr’ by default.
‘mvwaddstr()’ allows specifying both a window and a coordinate.

Fortunately the Python interface hides all these details.  ‘stdscr’ is a
window object like any other, and methods such as *note addstr(): 316b.
accept multiple argument forms.  Usually there are four different forms.

Form                                  Description
                                      
------------------------------------------------------------------------------------------
                                      
'str' or 'ch'                         Display the string 'str' or character 'ch' at the
                                      current position
                                      
                                      
'str' or 'ch', 'attr'                 Display the string 'str' or character 'ch', using
                                      attribute 'attr' at the current position
                                      
                                      
'y', 'x', 'str' or 'ch'               Move to position 'y,x' within the window, and
                                      display 'str' or 'ch'
                                      
                                      
'y', 'x', 'str' or 'ch', 'attr'       Move to position 'y,x' within the window, and
                                      display 'str' or 'ch', using attribute 'attr'
                                      

Attributes allow displaying text in highlighted forms such as boldface,
underline, reverse code, or in color.  They’ll be explained in more
detail in the next subsection.

The *note addstr(): 316b. method takes a Python string or bytestring as
the value to be displayed.  The contents of bytestrings are sent to the
terminal as-is.  Strings are encoded to bytes using the value of the
window’s *note encoding: 10da. attribute; this defaults to the default
system encoding as returned by *note locale.getencoding(): 2dc.

The *note addch(): 31ad. methods take a character, which can be either a
string of length 1, a bytestring of length 1, or an integer.

Constants are provided for extension characters; these constants are
integers greater than 255.  For example, *note ACS_PLMINUS: 327a. is a
+/- symbol, and *note ACS_ULCORNER: 31b7. is the upper left corner of a
box (handy for drawing borders).  You can also use the appropriate
Unicode character.

Windows remember where the cursor was left after the last operation, so
if you leave out the 'y,x' coordinates, the string or character will be
displayed wherever the last operation left off.  You can also move the
cursor with the ‘move(y,x)’ method.  Because some terminals always
display a flashing cursor, you may want to ensure that the cursor is
positioned in some location where it won’t be distracting; it can be
confusing to have the cursor blinking at some apparently random
location.

If your application doesn’t need a blinking cursor at all, you can call
‘curs_set(False)’ to make it invisible.  For compatibility with older
curses versions, there’s a ‘leaveok(bool)’ function that’s a synonym for
*note curs_set(): 3163.  When 'bool' is true, the curses library will
attempt to suppress the flashing cursor, and you won’t need to worry
about leaving it in odd locations.

* Menu:

* Attributes and Color::


File: python.info,  Node: Attributes and Color,  Up: Displaying Text

9.3.4.1 Attributes and Color
............................

Characters can be displayed in different ways.  Status lines in a
text-based application are commonly shown in reverse video, or a text
viewer may need to highlight certain words.  curses supports this by
allowing you to specify an attribute for each cell on the screen.

An attribute is an integer, each bit representing a different attribute.
You can try to display text with multiple attribute bits set, but curses
doesn’t guarantee that all the possible combinations are available, or
that they’re all visually distinct.  That depends on the ability of the
terminal being used, so it’s safest to stick to the most commonly
available attributes, listed here.

Attribute                  Description
                           
----------------------------------------------------------------------
                           
*note A_BLINK: 31f9.       Blinking text
                           
                           
*note A_BOLD: 31fa.        Extra bright or bold text
                           
                           
*note A_DIM: 31fb.         Half bright text
                           
                           
*note A_REVERSE: 3161.     Reverse-video text
                           
                           
*note A_STANDOUT: 3160.    The best highlighting mode available
                           
                           
*note A_UNDERLINE: 31ff.   Underlined text
                           

So, to display a reverse-video status line on the top line of the
screen, you could code:

     stdscr.addstr(0, 0, "Current mode: Typing mode",
                   curses.A_REVERSE)
     stdscr.refresh()

The curses library also supports color on those terminals that provide
it.  The most common such terminal is probably the Linux console,
followed by color xterms.

To use color, you must call the *note start_color(): 319e. function soon
after calling *note initscr(): 16a7, to initialize the default color set
(the *note curses.wrapper(): a8f. function does this automatically).
Once that’s done, the *note has_colors(): 3181. function returns TRUE if
the terminal in use can actually display color.  (Note: curses uses the
American spelling ‘color’, instead of the Canadian/British spelling
‘colour’.  If you’re used to the British spelling, you’ll have to resign
yourself to misspelling it for the sake of these functions.)

The curses library maintains a finite number of color pairs, containing
a foreground (or text) color and a background color.  You can get the
attribute value corresponding to a color pair with the *note
color_pair(): 315f. function; this can be bitwise-OR’ed with other
attributes such as *note A_REVERSE: 3161, but again, such combinations
are not guaranteed to work on all terminals.

An example, which displays a line of text using color pair 1:

     stdscr.addstr("Pretty text", curses.color_pair(1))
     stdscr.refresh()

As I said before, a color pair consists of a foreground and background
color.  The ‘init_pair(n, f, b)’ function changes the definition of
color pair 'n', to foreground color f and background color b.  Color
pair 0 is hard-wired to white on black, and cannot be changed.

Colors are numbered, and *note start_color(): 319e. initializes 8 basic
colors when it activates color mode.  They are: 0:black, 1:red, 2:green,
3:yellow, 4:blue, 5:magenta, 6:cyan, and 7:white.  The *note curses: 2b.
module defines named constants for each of these colors: *note
curses.COLOR_BLACK: 328c, *note curses.COLOR_RED: 3291, and so forth.

Let’s put all this together.  To change color 1 to red text on a white
background, you would call:

     curses.init_pair(1, curses.COLOR_RED, curses.COLOR_WHITE)

When you change a color pair, any text already displayed using that
color pair will change to the new colors.  You can also display new text
in this color with:

     stdscr.addstr(0,0, "RED ALERT!", curses.color_pair(1))

Very fancy terminals can change the definitions of the actual colors to
a given RGB value.  This lets you change color 1, which is usually red,
to purple or blue or any other color you like.  Unfortunately, the Linux
console doesn’t support this, so I’m unable to try it out, and can’t
provide any examples.  You can check if your terminal can do this by
calling *note can_change_color(): 315c, which returns ‘True’ if the
capability is there.  If you’re lucky enough to have such a talented
terminal, consult your system’s man pages for more information.


File: python.info,  Node: User Input,  Next: For More Information,  Prev: Displaying Text,  Up: Curses Programming with Python

9.3.5 User Input
----------------

The C curses library offers only very simple input mechanisms.  Python’s
*note curses: 2b. module adds a basic text-input widget.  (Other
libraries such as Urwid(1) have more extensive collections of widgets.)

There are two methods for getting input from a window:

   * *note getch(): 1647. refreshes the screen and then waits for the
     user to hit a key, displaying the key if *note echo(): 316d. has
     been called earlier.  You can optionally specify a coordinate to
     which the cursor should be moved before pausing.

   * *note getkey(): 31cb. does the same thing but converts the integer
     to a string.  Individual characters are returned as 1-character
     strings, and special keys such as function keys return longer
     strings containing a key name such as ‘KEY_UP’ or ‘^G’.

It’s possible to not wait for the user using the *note nodelay(): 31e1.
window method.  After ‘nodelay(True)’, ‘getch()’ and ‘getkey()’ for the
window become non-blocking.  To signal that no input is ready, ‘getch()’
returns ‘curses.ERR’ (a value of -1) and ‘getkey()’ raises an exception.
There’s also a *note halfdelay(): 3185. function, which can be used to
(in effect) set a timer on each ‘getch()’; if no input becomes available
within a specified delay (measured in tenths of a second), curses raises
an exception.

The ‘getch()’ method returns an integer; if it’s between 0 and 255, it
represents the ASCII code of the key pressed.  Values greater than 255
are special keys such as Page Up, Home, or the cursor keys.  You can
compare the value returned to constants such as *note curses.KEY_PPAGE:
321e, *note curses.KEY_HOME: 320f, or *note curses.KEY_LEFT: 320d.  The
main loop of your program may look something like this:

     while True:
         c = stdscr.getch()
         if c == ord('p'):
             PrintDocument()
         elif c == ord('q'):
             break  # Exit the while loop
         elif c == curses.KEY_HOME:
             x = y = 0

The *note curses.ascii: 2c. module supplies ASCII class membership
functions that take either integer or 1-character string arguments;
these may be useful in writing more readable tests for such loops.  It
also supplies conversion functions that take either integer or
1-character-string arguments and return the same type.  For example,
*note curses.ascii.ctrl(): 32d4. returns the control character
corresponding to its argument.

There’s also a method to retrieve an entire string, *note getstr():
31ce.  It isn’t used very often, because its functionality is quite
limited; the only editing keys available are the backspace key and the
Enter key, which terminates the string.  It can optionally be limited to
a fixed number of characters.

     curses.echo()            # Enable echoing of characters

     # Get a 15-character string, with the cursor on the top line
     s = stdscr.getstr(0,0, 15)

The *note curses.textpad: 2e. module supplies a text box that supports
an Emacs-like set of keybindings.  Various methods of the *note Textbox:
3295. class support editing with input validation and gathering the edit
results either with or without trailing spaces.  Here’s an example:

     import curses
     from curses.textpad import Textbox, rectangle

     def main(stdscr):
         stdscr.addstr(0, 0, "Enter IM message: (hit Ctrl-G to send)")

         editwin = curses.newwin(5,30, 2,1)
         rectangle(stdscr, 1,0, 1+5+1, 1+30+1)
         stdscr.refresh()

         box = Textbox(editwin)

         # Let the user edit until Ctrl-G is struck.
         box.edit()

         # Get resulting contents
         message = box.gather()

See the library documentation on *note curses.textpad: 2e. for more
details.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/Urwid/


File: python.info,  Node: For More Information,  Prev: User Input,  Up: Curses Programming with Python

9.3.6 For More Information
--------------------------

This HOWTO doesn’t cover some advanced topics, such as reading the
contents of the screen or capturing mouse events from an xterm instance,
but the Python library page for the *note curses: 2b. module is now
reasonably complete.  You should browse it next.

If you’re in doubt about the detailed behavior of the curses functions,
consult the manual pages for your curses implementation, whether it’s
ncurses or a proprietary Unix vendor’s.  The manual pages will document
any quirks, and provide complete lists of all the functions, attributes,
and *note ACS_*: 3266. characters available to you.

Because the curses API is so large, some functions aren’t supported in
the Python interface.  Often this isn’t because they’re difficult to
implement, but because no one has needed them yet.  Also, Python doesn’t
yet support the menu library associated with ncurses.  Patches adding
support for these would be welcome; see the Python Developer's Guide(1)
to learn more about submitting patches to Python.

   * Writing Programs with NCURSES(2): a lengthy tutorial for C
     programmers.

   * The ncurses man page(3)

   * The ncurses FAQ(4)

   * "Use curses...  don't swear"(5): video of a PyCon 2013 talk on
     controlling terminals using curses or Urwid.

   * "Console Applications with Urwid"(6): video of a PyCon CA 2012 talk
     demonstrating some applications written using Urwid.

   ---------- Footnotes ----------

   (1) https://devguide.python.org/

   (2) https://invisible-island.net/ncurses/ncurses-intro.html

   (3) https://linux.die.net/man/3/ncurses

   (4) https://invisible-island.net/ncurses/ncurses.faq.html

   (5) https://www.youtube.com/watch?v=eN1eZtjLEnU

   (6) https://pyvideo.org/video/1568/console-applications-with-urwid


File: python.info,  Node: Descriptor Guide,  Next: Debugging C API extensions and CPython Internals with GDB,  Prev: Curses Programming with Python,  Up: Python HOWTOs

9.4 Descriptor Guide
====================


Author: Raymond Hettinger


Contact: <python at rcn dot com>

*note Descriptors: 1677. let objects customize attribute lookup,
storage, and deletion.

This guide has four major sections:

  1. The “primer” gives a basic overview, moving gently from simple
     examples, adding one feature at a time.  Start here if you’re new
     to descriptors.

  2. The second section shows a complete, practical descriptor example.
     If you already know the basics, start there.

  3. The third section provides a more technical tutorial that goes into
     the detailed mechanics of how descriptors work.  Most people don’t
     need this level of detail.

  4. The last section has pure Python equivalents for built-in
     descriptors that are written in C. Read this if you’re curious
     about how functions turn into bound methods or about the
     implementation of common tools like *note classmethod(): 166, *note
     staticmethod(): 419, *note property(): 194, and *note __slots__:
     5e2.

* Menu:

* Primer::
* Complete Practical Example::
* Technical Tutorial::
* Pure Python Equivalents::


File: python.info,  Node: Primer,  Next: Complete Practical Example,  Up: Descriptor Guide

9.4.1 Primer
------------

In this primer, we start with the most basic possible example and then
we’ll add new capabilities one by one.

* Menu:

* Simple example; A descriptor that returns a constant: Simple example A descriptor that returns a constant.
* Dynamic lookups::
* Managed attributes::
* Customized names::
* Closing thoughts::


File: python.info,  Node: Simple example A descriptor that returns a constant,  Next: Dynamic lookups,  Up: Primer

9.4.1.1 Simple example: A descriptor that returns a constant
............................................................

The ‘Ten’ class is a descriptor whose *note __get__(): 1537. method
always returns the constant ‘10’:

     class Ten:
         def __get__(self, obj, objtype=None):
             return 10

To use the descriptor, it must be stored as a class variable in another
class:

     class A:
         x = 5                       # Regular class attribute
         y = Ten()                   # Descriptor instance

An interactive session shows the difference between normal attribute
lookup and descriptor lookup:

     >>> a = A()                     # Make an instance of class A
     >>> a.x                         # Normal attribute lookup
     5
     >>> a.y                         # Descriptor lookup
     10

In the ‘a.x’ attribute lookup, the dot operator finds ‘'x': 5’ in the
class dictionary.  In the ‘a.y’ lookup, the dot operator finds a
descriptor instance, recognized by its ‘__get__’ method.  Calling that
method returns ‘10’.

Note that the value ‘10’ is not stored in either the class dictionary or
the instance dictionary.  Instead, the value ‘10’ is computed on demand.

This example shows how a simple descriptor works, but it isn’t very
useful.  For retrieving constants, normal attribute lookup would be
better.

In the next section, we’ll create something more useful, a dynamic
lookup.


File: python.info,  Node: Dynamic lookups,  Next: Managed attributes,  Prev: Simple example A descriptor that returns a constant,  Up: Primer

9.4.1.2 Dynamic lookups
.......................

Interesting descriptors typically run computations instead of returning
constants:

     import os

     class DirectorySize:

         def __get__(self, obj, objtype=None):
             return len(os.listdir(obj.dirname))

     class Directory:

         size = DirectorySize()              # Descriptor instance

         def __init__(self, dirname):
             self.dirname = dirname          # Regular instance attribute

An interactive session shows that the lookup is dynamic — it computes
different, updated answers each time:

     >>> s = Directory('songs')
     >>> g = Directory('games')
     >>> s.size                              # The songs directory has twenty files
     20
     >>> g.size                              # The games directory has three files
     3
     >>> os.remove('games/chess')            # Delete a game
     >>> g.size                              # File count is automatically updated
     2

Besides showing how descriptors can run computations, this example also
reveals the purpose of the parameters to *note __get__(): 1537.  The
'self' parameter is 'size', an instance of 'DirectorySize'.  The 'obj'
parameter is either 'g' or 's', an instance of 'Directory'.  It is the
'obj' parameter that lets the ‘__get__()’ method learn the target
directory.  The 'objtype' parameter is the class 'Directory'.


File: python.info,  Node: Managed attributes,  Next: Customized names,  Prev: Dynamic lookups,  Up: Primer

9.4.1.3 Managed attributes
..........................

A popular use for descriptors is managing access to instance data.  The
descriptor is assigned to a public attribute in the class dictionary
while the actual data is stored as a private attribute in the instance
dictionary.  The descriptor’s *note __get__(): 1537. and *note
__set__(): 211b. methods are triggered when the public attribute is
accessed.

In the following example, 'age' is the public attribute and '_age' is
the private attribute.  When the public attribute is accessed, the
descriptor logs the lookup or update:

     import logging

     logging.basicConfig(level=logging.INFO)

     class LoggedAgeAccess:

         def __get__(self, obj, objtype=None):
             value = obj._age
             logging.info('Accessing %r giving %r', 'age', value)
             return value

         def __set__(self, obj, value):
             logging.info('Updating %r to %r', 'age', value)
             obj._age = value

     class Person:

         age = LoggedAgeAccess()             # Descriptor instance

         def __init__(self, name, age):
             self.name = name                # Regular instance attribute
             self.age = age                  # Calls __set__()

         def birthday(self):
             self.age += 1                   # Calls both __get__() and __set__()

An interactive session shows that all access to the managed attribute
'age' is logged, but that the regular attribute 'name' is not logged:

     >>> mary = Person('Mary M', 30)         # The initial age update is logged
     INFO:root:Updating 'age' to 30
     >>> dave = Person('David D', 40)
     INFO:root:Updating 'age' to 40

     >>> vars(mary)                          # The actual data is in a private attribute
     {'name': 'Mary M', '_age': 30}
     >>> vars(dave)
     {'name': 'David D', '_age': 40}

     >>> mary.age                            # Access the data and log the lookup
     INFO:root:Accessing 'age' giving 30
     30
     >>> mary.birthday()                     # Updates are logged as well
     INFO:root:Accessing 'age' giving 30
     INFO:root:Updating 'age' to 31

     >>> dave.name                           # Regular attribute lookup isn't logged
     'David D'
     >>> dave.age                            # Only the managed attribute is logged
     INFO:root:Accessing 'age' giving 40
     40

One major issue with this example is that the private name '_age' is
hardwired in the 'LoggedAgeAccess' class.  That means that each instance
can only have one logged attribute and that its name is unchangeable.
In the next example, we’ll fix that problem.


File: python.info,  Node: Customized names,  Next: Closing thoughts,  Prev: Managed attributes,  Up: Primer

9.4.1.4 Customized names
........................

When a class uses descriptors, it can inform each descriptor about which
variable name was used.

In this example, the ‘Person’ class has two descriptor instances, 'name'
and 'age'.  When the ‘Person’ class is defined, it makes a callback to
*note __set_name__(): c6f. in 'LoggedAccess' so that the field names can
be recorded, giving each descriptor its own 'public_name' and
'private_name':

     import logging

     logging.basicConfig(level=logging.INFO)

     class LoggedAccess:

         def __set_name__(self, owner, name):
             self.public_name = name
             self.private_name = '_' + name

         def __get__(self, obj, objtype=None):
             value = getattr(obj, self.private_name)
             logging.info('Accessing %r giving %r', self.public_name, value)
             return value

         def __set__(self, obj, value):
             logging.info('Updating %r to %r', self.public_name, value)
             setattr(obj, self.private_name, value)

     class Person:

         name = LoggedAccess()                # First descriptor instance
         age = LoggedAccess()                 # Second descriptor instance

         def __init__(self, name, age):
             self.name = name                 # Calls the first descriptor
             self.age = age                   # Calls the second descriptor

         def birthday(self):
             self.age += 1

An interactive session shows that the ‘Person’ class has called *note
__set_name__(): c6f. so that the field names would be recorded.  Here we
call *note vars(): 1bd2. to look up the descriptor without triggering
it:

     >>> vars(vars(Person)['name'])
     {'public_name': 'name', 'private_name': '_name'}
     >>> vars(vars(Person)['age'])
     {'public_name': 'age', 'private_name': '_age'}

The new class now logs access to both 'name' and 'age':

     >>> pete = Person('Peter P', 10)
     INFO:root:Updating 'name' to 'Peter P'
     INFO:root:Updating 'age' to 10
     >>> kate = Person('Catherine C', 20)
     INFO:root:Updating 'name' to 'Catherine C'
     INFO:root:Updating 'age' to 20

The two 'Person' instances contain only the private names:

     >>> vars(pete)
     {'_name': 'Peter P', '_age': 10}
     >>> vars(kate)
     {'_name': 'Catherine C', '_age': 20}


File: python.info,  Node: Closing thoughts,  Prev: Customized names,  Up: Primer

9.4.1.5 Closing thoughts
........................

A *note descriptor: 1677. is what we call any object that defines *note
__get__(): 1537, *note __set__(): 211b, or *note __delete__(): 1713.

Optionally, descriptors can have a *note __set_name__(): c6f. method.
This is only used in cases where a descriptor needs to know either the
class where it was created or the name of class variable it was assigned
to.  (This method, if present, is called even if the class is not a
descriptor.)

Descriptors get invoked by the dot operator during attribute lookup.  If
a descriptor is accessed indirectly with
‘vars(some_class)[descriptor_name]’, the descriptor instance is returned
without invoking it.

Descriptors only work when used as class variables.  When put in
instances, they have no effect.

The main motivation for descriptors is to provide a hook allowing
objects stored in class variables to control what happens during
attribute lookup.

Traditionally, the calling class controls what happens during lookup.
Descriptors invert that relationship and allow the data being looked-up
to have a say in the matter.

Descriptors are used throughout the language.  It is how functions turn
into bound methods.  Common tools like *note classmethod(): 166, *note
staticmethod(): 419, *note property(): 194, and *note
functools.cached_property(): 544. are all implemented as descriptors.


File: python.info,  Node: Complete Practical Example,  Next: Technical Tutorial,  Prev: Primer,  Up: Descriptor Guide

9.4.2 Complete Practical Example
--------------------------------

In this example, we create a practical and powerful tool for locating
notoriously hard to find data corruption bugs.

* Menu:

* Validator class::
* Custom validators::
* Practical application::


File: python.info,  Node: Validator class,  Next: Custom validators,  Up: Complete Practical Example

9.4.2.1 Validator class
.......................

A validator is a descriptor for managed attribute access.  Prior to
storing any data, it verifies that the new value meets various type and
range restrictions.  If those restrictions aren’t met, it raises an
exception to prevent data corruption at its source.

This ‘Validator’ class is both an *note abstract base class: 11fa. and a
managed attribute descriptor:

     from abc import ABC, abstractmethod

     class Validator(ABC):

         def __set_name__(self, owner, name):
             self.private_name = '_' + name

         def __get__(self, obj, objtype=None):
             return getattr(obj, self.private_name)

         def __set__(self, obj, value):
             self.validate(value)
             setattr(obj, self.private_name, value)

         @abstractmethod
         def validate(self, value):
             pass

Custom validators need to inherit from ‘Validator’ and must supply a
‘validate()’ method to test various restrictions as needed.


File: python.info,  Node: Custom validators,  Next: Practical application,  Prev: Validator class,  Up: Complete Practical Example

9.4.2.2 Custom validators
.........................

Here are three practical data validation utilities:

  1. ‘OneOf’ verifies that a value is one of a restricted set of
     options.

  2. ‘Number’ verifies that a value is either an *note int: 257. or
     *note float: 2f7.  Optionally, it verifies that a value is between
     a given minimum or maximum.

  3. ‘String’ verifies that a value is a *note str: 44f.  Optionally, it
     validates a given minimum or maximum length.  It can validate a
     user-defined predicate(1) as well.

     class OneOf(Validator):

         def __init__(self, *options):
             self.options = set(options)

         def validate(self, value):
             if value not in self.options:
                 raise ValueError(
                     f'Expected {value!r} to be one of {self.options!r}'
                 )

     class Number(Validator):

         def __init__(self, minvalue=None, maxvalue=None):
             self.minvalue = minvalue
             self.maxvalue = maxvalue

         def validate(self, value):
             if not isinstance(value, (int, float)):
                 raise TypeError(f'Expected {value!r} to be an int or float')
             if self.minvalue is not None and value < self.minvalue:
                 raise ValueError(
                     f'Expected {value!r} to be at least {self.minvalue!r}'
                 )
             if self.maxvalue is not None and value > self.maxvalue:
                 raise ValueError(
                     f'Expected {value!r} to be no more than {self.maxvalue!r}'
                 )

     class String(Validator):

         def __init__(self, minsize=None, maxsize=None, predicate=None):
             self.minsize = minsize
             self.maxsize = maxsize
             self.predicate = predicate

         def validate(self, value):
             if not isinstance(value, str):
                 raise TypeError(f'Expected {value!r} to be a str')
             if self.minsize is not None and len(value) < self.minsize:
                 raise ValueError(
                     f'Expected {value!r} to be no smaller than {self.minsize!r}'
                 )
             if self.maxsize is not None and len(value) > self.maxsize:
                 raise ValueError(
                     f'Expected {value!r} to be no bigger than {self.maxsize!r}'
                 )
             if self.predicate is not None and not self.predicate(value):
                 raise ValueError(
                     f'Expected {self.predicate} to be true for {value!r}'
                 )

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Predicate_(mathematical_logic)


File: python.info,  Node: Practical application,  Prev: Custom validators,  Up: Complete Practical Example

9.4.2.3 Practical application
.............................

Here’s how the data validators can be used in a real class:

     class Component:

         name = String(minsize=3, maxsize=10, predicate=str.isupper)
         kind = OneOf('wood', 'metal', 'plastic')
         quantity = Number(minvalue=0)

         def __init__(self, name, kind, quantity):
             self.name = name
             self.kind = kind
             self.quantity = quantity

The descriptors prevent invalid instances from being created:

     >>> Component('Widget', 'metal', 5)      # Blocked: 'Widget' is not all uppercase
     Traceback (most recent call last):
         ...
     ValueError: Expected <method 'isupper' of 'str' objects> to be true for 'Widget'

     >>> Component('WIDGET', 'metle', 5)      # Blocked: 'metle' is misspelled
     Traceback (most recent call last):
         ...
     ValueError: Expected 'metle' to be one of {'metal', 'plastic', 'wood'}

     >>> Component('WIDGET', 'metal', -5)     # Blocked: -5 is negative
     Traceback (most recent call last):
         ...
     ValueError: Expected -5 to be at least 0

     >>> Component('WIDGET', 'metal', 'V')    # Blocked: 'V' isn't a number
     Traceback (most recent call last):
         ...
     TypeError: Expected 'V' to be an int or float

     >>> c = Component('WIDGET', 'metal', 5)  # Allowed:  The inputs are valid


File: python.info,  Node: Technical Tutorial,  Next: Pure Python Equivalents,  Prev: Complete Practical Example,  Up: Descriptor Guide

9.4.3 Technical Tutorial
------------------------

What follows is a more technical tutorial for the mechanics and details
of how descriptors work.

* Menu:

* Abstract::
* Definition and introduction::
* Descriptor protocol::
* Overview of descriptor invocation::
* Invocation from an instance::
* Invocation from a class::
* Invocation from super::
* Summary of invocation logic::
* Automatic name notification::
* ORM example::


File: python.info,  Node: Abstract,  Next: Definition and introduction,  Up: Technical Tutorial

9.4.3.1 Abstract
................

Defines descriptors, summarizes the protocol, and shows how descriptors
are called.  Provides an example showing how object relational mappings
work.

Learning about descriptors not only provides access to a larger toolset,
it creates a deeper understanding of how Python works.


File: python.info,  Node: Definition and introduction,  Next: Descriptor protocol,  Prev: Abstract,  Up: Technical Tutorial

9.4.3.2 Definition and introduction
...................................

In general, a descriptor is an attribute value that has one of the
methods in the descriptor protocol.  Those methods are *note __get__():
1537, *note __set__(): 211b, and *note __delete__(): 1713.  If any of
those methods are defined for an attribute, it is said to be a *note
descriptor: 1677.

The default behavior for attribute access is to get, set, or delete the
attribute from an object’s dictionary.  For instance, ‘a.x’ has a lookup
chain starting with ‘a.__dict__['x']’, then ‘type(a).__dict__['x']’, and
continuing through the method resolution order of ‘type(a)’.  If the
looked-up value is an object defining one of the descriptor methods,
then Python may override the default behavior and invoke the descriptor
method instead.  Where this occurs in the precedence chain depends on
which descriptor methods were defined.

Descriptors are a powerful, general purpose protocol.  They are the
mechanism behind properties, methods, static methods, class methods, and
*note super(): 4de.  They are used throughout Python itself.
Descriptors simplify the underlying C code and offer a flexible set of
new tools for everyday Python programs.


File: python.info,  Node: Descriptor protocol,  Next: Overview of descriptor invocation,  Prev: Definition and introduction,  Up: Technical Tutorial

9.4.3.3 Descriptor protocol
...........................

‘descr.__get__(self, obj, type=None)’

‘descr.__set__(self, obj, value)’

‘descr.__delete__(self, obj)’

That is all there is to it.  Define any of these methods and an object
is considered a descriptor and can override default behavior upon being
looked up as an attribute.

If an object defines *note __set__(): 211b. or *note __delete__(): 1713,
it is considered a data descriptor.  Descriptors that only define *note
__get__(): 1537. are called non-data descriptors (they are often used
for methods but other uses are possible).

Data and non-data descriptors differ in how overrides are calculated
with respect to entries in an instance’s dictionary.  If an instance’s
dictionary has an entry with the same name as a data descriptor, the
data descriptor takes precedence.  If an instance’s dictionary has an
entry with the same name as a non-data descriptor, the dictionary entry
takes precedence.

To make a read-only data descriptor, define both *note __get__(): 1537.
and *note __set__(): 211b. with the ‘__set__()’ raising an *note
AttributeError: 34e. when called.  Defining the ‘__set__()’ method with
an exception raising placeholder is enough to make it a data descriptor.


File: python.info,  Node: Overview of descriptor invocation,  Next: Invocation from an instance,  Prev: Descriptor protocol,  Up: Technical Tutorial

9.4.3.4 Overview of descriptor invocation
.........................................

A descriptor can be called directly with ‘desc.__get__(obj)’ or
‘desc.__get__(None, cls)’.

But it is more common for a descriptor to be invoked automatically from
attribute access.

The expression ‘obj.x’ looks up the attribute ‘x’ in the chain of
namespaces for ‘obj’.  If the search finds a descriptor outside of the
instance *note __dict__: 55e, its *note __get__(): 1537. method is
invoked according to the precedence rules listed below.

The details of invocation depend on whether ‘obj’ is an object, class,
or instance of super.


File: python.info,  Node: Invocation from an instance,  Next: Invocation from a class,  Prev: Overview of descriptor invocation,  Up: Technical Tutorial

9.4.3.5 Invocation from an instance
...................................

Instance lookup scans through a chain of namespaces giving data
descriptors the highest priority, followed by instance variables, then
non-data descriptors, then class variables, and lastly *note
__getattr__(): 4d6. if it is provided.

If a descriptor is found for ‘a.x’, then it is invoked with:
‘desc.__get__(a, type(a))’.

The logic for a dotted lookup is in *note object.__getattribute__():
bf1.  Here is a pure Python equivalent:

     def find_name_in_mro(cls, name, default):
         "Emulate _PyType_Lookup() in Objects/typeobject.c"
         for base in cls.__mro__:
             if name in vars(base):
                 return vars(base)[name]
         return default

     def object_getattribute(obj, name):
         "Emulate PyObject_GenericGetAttr() in Objects/object.c"
         null = object()
         objtype = type(obj)
         cls_var = find_name_in_mro(objtype, name, null)
         descr_get = getattr(type(cls_var), '__get__', null)
         if descr_get is not null:
             if (hasattr(type(cls_var), '__set__')
                 or hasattr(type(cls_var), '__delete__')):
                 return descr_get(cls_var, obj, objtype)     # data descriptor
         if hasattr(obj, '__dict__') and name in vars(obj):
             return vars(obj)[name]                          # instance variable
         if descr_get is not null:
             return descr_get(cls_var, obj, objtype)         # non-data descriptor
         if cls_var is not null:
             return cls_var                                  # class variable
         raise AttributeError(name)

Note, there is no *note __getattr__(): 4d6. hook in the *note
__getattribute__(): bf1. code.  That is why calling ‘__getattribute__()’
directly or with ‘super().__getattribute__’ will bypass ‘__getattr__()’
entirely.

Instead, it is the dot operator and the *note getattr(): bf0. function
that are responsible for invoking *note __getattr__(): 4d6. whenever
*note __getattribute__(): bf1. raises an *note AttributeError: 34e.
Their logic is encapsulated in a helper function:

     def getattr_hook(obj, name):
         "Emulate slot_tp_getattr_hook() in Objects/typeobject.c"
         try:
             return obj.__getattribute__(name)
         except AttributeError:
             if not hasattr(type(obj), '__getattr__'):
                 raise
         return type(obj).__getattr__(obj, name)             # __getattr__


File: python.info,  Node: Invocation from a class,  Next: Invocation from super,  Prev: Invocation from an instance,  Up: Technical Tutorial

9.4.3.6 Invocation from a class
...............................

The logic for a dotted lookup such as ‘A.x’ is in
‘type.__getattribute__()’.  The steps are similar to those for
‘object.__getattribute__()’ but the instance dictionary lookup is
replaced by a search through the class’s *note method resolution order:
2339.

If a descriptor is found, it is invoked with ‘desc.__get__(None, A)’.

The full C implementation can be found in ‘type_getattro()’ and
‘_PyType_Lookup()’ in Objects/typeobject.c(1).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Objects/typeobject.c


File: python.info,  Node: Invocation from super,  Next: Summary of invocation logic,  Prev: Invocation from a class,  Up: Technical Tutorial

9.4.3.7 Invocation from super
.............................

The logic for super’s dotted lookup is in the *note __getattribute__():
bf1. method for object returned by *note super(): 4de.

A dotted lookup such as ‘super(A, obj).m’ searches
‘obj.__class__.__mro__’ for the base class ‘B’ immediately following ‘A’
and then returns ‘B.__dict__['m'].__get__(obj, A)’.  If not a
descriptor, ‘m’ is returned unchanged.

The full C implementation can be found in ‘super_getattro()’ in
Objects/typeobject.c(1).  A pure Python equivalent can be found in
Guido's Tutorial(2).

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Objects/typeobject.c

   (2) 
https://www.python.org/download/releases/2.2.3/descrintro/#cooperation


File: python.info,  Node: Summary of invocation logic,  Next: Automatic name notification,  Prev: Invocation from super,  Up: Technical Tutorial

9.4.3.8 Summary of invocation logic
...................................

The mechanism for descriptors is embedded in the *note
__getattribute__(): bf1. methods for *note object: a9b, *note type: d71,
and *note super(): 4de.

The important points to remember are:

   * Descriptors are invoked by the *note __getattribute__(): bf1.
     method.

   * Classes inherit this machinery from *note object: a9b, *note type:
     d71, or *note super(): 4de.

   * Overriding *note __getattribute__(): bf1. prevents automatic
     descriptor calls because all the descriptor logic is in that
     method.

   * ‘object.__getattribute__()’ and ‘type.__getattribute__()’ make
     different calls to *note __get__(): 1537.  The first includes the
     instance and may include the class.  The second puts in ‘None’ for
     the instance and always includes the class.

   * Data descriptors always override instance dictionaries.

   * Non-data descriptors may be overridden by instance dictionaries.


File: python.info,  Node: Automatic name notification,  Next: ORM example,  Prev: Summary of invocation logic,  Up: Technical Tutorial

9.4.3.9 Automatic name notification
...................................

Sometimes it is desirable for a descriptor to know what class variable
name it was assigned to.  When a new class is created, the *note type:
d71. metaclass scans the dictionary of the new class.  If any of the
entries are descriptors and if they define *note __set_name__(): c6f,
that method is called with two arguments.  The 'owner' is the class
where the descriptor is used, and the 'name' is the class variable the
descriptor was assigned to.

The implementation details are in ‘type_new()’ and ‘set_names()’ in
Objects/typeobject.c(1).

Since the update logic is in ‘type.__new__()’, notifications only take
place at the time of class creation.  If descriptors are added to the
class afterwards, *note __set_name__(): c6f. will need to be called
manually.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Objects/typeobject.c


File: python.info,  Node: ORM example,  Prev: Automatic name notification,  Up: Technical Tutorial

9.4.3.10 ORM example
....................

The following code is a simplified skeleton showing how data descriptors
could be used to implement an object relational mapping(1).

The essential idea is that the data is stored in an external database.
The Python instances only hold keys to the database’s tables.
Descriptors take care of lookups or updates:

     class Field:

         def __set_name__(self, owner, name):
             self.fetch = f'SELECT {name} FROM {owner.table} WHERE {owner.key}=?;'
             self.store = f'UPDATE {owner.table} SET {name}=? WHERE {owner.key}=?;'

         def __get__(self, obj, objtype=None):
             return conn.execute(self.fetch, [obj.key]).fetchone()[0]

         def __set__(self, obj, value):
             conn.execute(self.store, [value, obj.key])
             conn.commit()

We can use the ‘Field’ class to define models(2) that describe the
schema for each table in a database:

     class Movie:
         table = 'Movies'                    # Table name
         key = 'title'                       # Primary key
         director = Field()
         year = Field()

         def __init__(self, key):
             self.key = key

     class Song:
         table = 'Music'
         key = 'title'
         artist = Field()
         year = Field()
         genre = Field()

         def __init__(self, key):
             self.key = key

To use the models, first connect to the database:

     >>> import sqlite3
     >>> conn = sqlite3.connect('entertainment.db')

An interactive session shows how data is retrieved from the database and
how it can be updated:

     >>> Movie('Star Wars').director
     'George Lucas'
     >>> jaws = Movie('Jaws')
     >>> f'Released in {jaws.year} by {jaws.director}'
     'Released in 1975 by Steven Spielberg'

     >>> Song('Country Roads').artist
     'John Denver'

     >>> Movie('Star Wars').director = 'J.J. Abrams'
     >>> Movie('Star Wars').director
     'J.J. Abrams'

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Object%E2%80%93relational_mapping

   (2) https://en.wikipedia.org/wiki/Database_model


File: python.info,  Node: Pure Python Equivalents,  Prev: Technical Tutorial,  Up: Descriptor Guide

9.4.4 Pure Python Equivalents
-----------------------------

The descriptor protocol is simple and offers exciting possibilities.
Several use cases are so common that they have been prepackaged into
built-in tools.  Properties, bound methods, static methods, class
methods, and __slots__ are all based on the descriptor protocol.

* Menu:

* Properties::
* Functions and methods::
* Kinds of methods::
* Static methods::
* Class methods::
* Member objects and __slots__::


File: python.info,  Node: Properties,  Next: Functions and methods,  Up: Pure Python Equivalents

9.4.4.1 Properties
..................

Calling *note property(): 194. is a succinct way of building a data
descriptor that triggers a function call upon access to an attribute.
Its signature is:

     property(fget=None, fset=None, fdel=None, doc=None) -> property

The documentation shows a typical use to define a managed attribute ‘x’:

     class C:
         def getx(self): return self.__x
         def setx(self, value): self.__x = value
         def delx(self): del self.__x
         x = property(getx, setx, delx, "I'm the 'x' property.")

To see how *note property(): 194. is implemented in terms of the
descriptor protocol, here is a pure Python equivalent that implements
most of the core functionality:

     class Property:
         "Emulate PyProperty_Type() in Objects/descrobject.c"

         def __init__(self, fget=None, fset=None, fdel=None, doc=None):
             self.fget = fget
             self.fset = fset
             self.fdel = fdel
             if doc is None and fget is not None:
                 doc = fget.__doc__
             self.__doc__ = doc

         def __set_name__(self, owner, name):
             self.__name__ = name

         def __get__(self, obj, objtype=None):
             if obj is None:
                 return self
             if self.fget is None:
                 raise AttributeError
             return self.fget(obj)

         def __set__(self, obj, value):
             if self.fset is None:
                 raise AttributeError
             self.fset(obj, value)

         def __delete__(self, obj):
             if self.fdel is None:
                 raise AttributeError
             self.fdel(obj)

         def getter(self, fget):
             return type(self)(fget, self.fset, self.fdel, self.__doc__)

         def setter(self, fset):
             return type(self)(self.fget, fset, self.fdel, self.__doc__)

         def deleter(self, fdel):
             return type(self)(self.fget, self.fset, fdel, self.__doc__)

The *note property(): 194. builtin helps whenever a user interface has
granted attribute access and then subsequent changes require the
intervention of a method.

For instance, a spreadsheet class may grant access to a cell value
through ‘Cell('b10').value’.  Subsequent improvements to the program
require the cell to be recalculated on every access; however, the
programmer does not want to affect existing client code accessing the
attribute directly.  The solution is to wrap access to the value
attribute in a property data descriptor:

     class Cell:
         ...

         @property
         def value(self):
             "Recalculate the cell before returning value"
             self.recalc()
             return self._value

Either the built-in *note property(): 194. or our ‘Property()’
equivalent would work in this example.


File: python.info,  Node: Functions and methods,  Next: Kinds of methods,  Prev: Properties,  Up: Pure Python Equivalents

9.4.4.2 Functions and methods
.............................

Python’s object oriented features are built upon a function based
environment.  Using non-data descriptors, the two are merged seamlessly.

Functions stored in class dictionaries get turned into methods when
invoked.  Methods only differ from regular functions in that the object
instance is prepended to the other arguments.  By convention, the
instance is called 'self' but could be called 'this' or any other
variable name.

Methods can be created manually with *note types.MethodType: 1929. which
is roughly equivalent to:

     class MethodType:
         "Emulate PyMethod_Type in Objects/classobject.c"

         def __init__(self, func, obj):
             self.__func__ = func
             self.__self__ = obj

         def __call__(self, *args, **kwargs):
             func = self.__func__
             obj = self.__self__
             return func(obj, *args, **kwargs)

         def __getattribute__(self, name):
             "Emulate method_getset() in Objects/classobject.c"
             if name == '__doc__':
                 return self.__func__.__doc__
             return object.__getattribute__(self, name)

         def __getattr__(self, name):
             "Emulate method_getattro() in Objects/classobject.c"
             return getattr(self.__func__, name)

         def __get__(self, obj, objtype=None):
             "Emulate method_descr_get() in Objects/classobject.c"
             return self

To support automatic creation of methods, functions include the *note
__get__(): 1537. method for binding methods during attribute access.
This means that functions are non-data descriptors that return bound
methods during dotted lookup from an instance.  Here’s how it works:

     class Function:
         ...

         def __get__(self, obj, objtype=None):
             "Simulate func_descr_get() in Objects/funcobject.c"
             if obj is None:
                 return self
             return MethodType(self, obj)

Running the following class in the interpreter shows how the function
descriptor works in practice:

     class D:
         def f(self):
              return self

     class D2:
         pass

The function has a *note qualified name: 1acb. attribute to support
introspection:

     >>> D.f.__qualname__
     'D.f'

Accessing the function through the class dictionary does not invoke
*note __get__(): 1537.  Instead, it just returns the underlying function
object:

     >>> D.__dict__['f']
     <function D.f at 0x00C45070>

Dotted access from a class calls *note __get__(): 1537. which just
returns the underlying function unchanged:

     >>> D.f
     <function D.f at 0x00C45070>

The interesting behavior occurs during dotted access from an instance.
The dotted lookup calls *note __get__(): 1537. which returns a bound
method object:

     >>> d = D()
     >>> d.f
     <bound method D.f of <__main__.D object at 0x00B18C90>>

Internally, the bound method stores the underlying function and the
bound instance:

     >>> d.f.__func__
     <function D.f at 0x00C45070>

     >>> d.f.__self__
     <__main__.D object at 0x00B18C90>

If you have ever wondered where 'self' comes from in regular methods or
where 'cls' comes from in class methods, this is it!


File: python.info,  Node: Kinds of methods,  Next: Static methods,  Prev: Functions and methods,  Up: Pure Python Equivalents

9.4.4.3 Kinds of methods
........................

Non-data descriptors provide a simple mechanism for variations on the
usual patterns of binding functions into methods.

To recap, functions have a *note __get__(): 1537. method so that they
can be converted to a method when accessed as attributes.  The non-data
descriptor transforms an ‘obj.f(*args)’ call into ‘f(obj, *args)’.
Calling ‘cls.f(*args)’ becomes ‘f(*args)’.

This chart summarizes the binding and its two most useful variants:

     Transformation        Called from an object      Called from a class
                                                      
     ------------------------------------------------------------------------
                                                      
     function              f(obj, *args)              f(*args)
                                                      
                                                      
     staticmethod          f(*args)                   f(*args)
                                                      
                                                      
     classmethod           f(type(obj), *args)        f(cls, *args)
                                                      


File: python.info,  Node: Static methods,  Next: Class methods,  Prev: Kinds of methods,  Up: Pure Python Equivalents

9.4.4.4 Static methods
......................

Static methods return the underlying function without changes.  Calling
either ‘c.f’ or ‘C.f’ is the equivalent of a direct lookup into
‘object.__getattribute__(c, "f")’ or ‘object.__getattribute__(C, "f")’.
As a result, the function becomes identically accessible from either an
object or a class.

Good candidates for static methods are methods that do not reference the
‘self’ variable.

For instance, a statistics package may include a container class for
experimental data.  The class provides normal methods for computing the
average, mean, median, and other descriptive statistics that depend on
the data.  However, there may be useful functions which are conceptually
related but do not depend on the data.  For instance, ‘erf(x)’ is handy
conversion routine that comes up in statistical work but does not
directly depend on a particular dataset.  It can be called either from
an object or the class: ‘s.erf(1.5) --> 0.9332’ or ‘Sample.erf(1.5) -->
0.9332’.

Since static methods return the underlying function with no changes, the
example calls are unexciting:

     class E:
         @staticmethod
         def f(x):
             return x * 10

     >>> E.f(3)
     30
     >>> E().f(3)
     30

Using the non-data descriptor protocol, a pure Python version of *note
staticmethod(): 419. would look like this:

     import functools

     class StaticMethod:
         "Emulate PyStaticMethod_Type() in Objects/funcobject.c"

         def __init__(self, f):
             self.f = f
             functools.update_wrapper(self, f)

         def __get__(self, obj, objtype=None):
             return self.f

         def __call__(self, *args, **kwds):
             return self.f(*args, **kwds)

The *note functools.update_wrapper(): 105d. call adds a ‘__wrapped__’
attribute that refers to the underlying function.  Also it carries
forward the attributes necessary to make the wrapper look like the
wrapped function: *note __name__: 131c, *note __qualname__: 20ac, *note
__doc__: 121e, and *note __annotations__: 121d.


File: python.info,  Node: Class methods,  Next: Member objects and __slots__,  Prev: Static methods,  Up: Pure Python Equivalents

9.4.4.5 Class methods
.....................

Unlike static methods, class methods prepend the class reference to the
argument list before calling the function.  This format is the same for
whether the caller is an object or a class:

     class F:
         @classmethod
         def f(cls, x):
             return cls.__name__, x

     >>> F.f(3)
     ('F', 3)
     >>> F().f(3)
     ('F', 3)

This behavior is useful whenever the method only needs to have a class
reference and does not rely on data stored in a specific instance.  One
use for class methods is to create alternate class constructors.  For
example, the classmethod *note dict.fromkeys(): 1656. creates a new
dictionary from a list of keys.  The pure Python equivalent is:

     class Dict(dict):
         @classmethod
         def fromkeys(cls, iterable, value=None):
             "Emulate dict_fromkeys() in Objects/dictobject.c"
             d = cls()
             for key in iterable:
                 d[key] = value
             return d

Now a new dictionary of unique keys can be constructed like this:

     >>> d = Dict.fromkeys('abracadabra')
     >>> type(d) is Dict
     True
     >>> d
     {'a': None, 'b': None, 'r': None, 'c': None, 'd': None}

Using the non-data descriptor protocol, a pure Python version of *note
classmethod(): 166. would look like this:

     import functools

     class ClassMethod:
         "Emulate PyClassMethod_Type() in Objects/funcobject.c"

         def __init__(self, f):
             self.f = f
             functools.update_wrapper(self, f)

         def __get__(self, obj, cls=None):
             if cls is None:
                 cls = type(obj)
             return MethodType(self.f, cls)

The *note functools.update_wrapper(): 105d. call in ‘ClassMethod’ adds a
‘__wrapped__’ attribute that refers to the underlying function.  Also it
carries forward the attributes necessary to make the wrapper look like
the wrapped function: *note __name__: 131c, *note __qualname__: 20ac,
*note __doc__: 121e, and *note __annotations__: 121d.


File: python.info,  Node: Member objects and __slots__,  Prev: Class methods,  Up: Pure Python Equivalents

9.4.4.6 Member objects and __slots__
....................................

When a class defines ‘__slots__’, it replaces instance dictionaries with
a fixed-length array of slot values.  From a user point of view that has
several effects:

1.  Provides immediate detection of bugs due to misspelled attribute
assignments.  Only attribute names specified in ‘__slots__’ are allowed:

     class Vehicle:
         __slots__ = ('id_number', 'make', 'model')

     >>> auto = Vehicle()
     >>> auto.id_nubmer = 'VYE483814LQEX'
     Traceback (most recent call last):
         ...
     AttributeError: 'Vehicle' object has no attribute 'id_nubmer'

2.  Helps create immutable objects where descriptors manage access to
private attributes stored in ‘__slots__’:

     class Immutable:

         __slots__ = ('_dept', '_name')          # Replace the instance dictionary

         def __init__(self, dept, name):
             self._dept = dept                   # Store to private attribute
             self._name = name                   # Store to private attribute

         @property                               # Read-only descriptor
         def dept(self):
             return self._dept

         @property
         def name(self):                         # Read-only descriptor
             return self._name

     >>> mark = Immutable('Botany', 'Mark Watney')
     >>> mark.dept
     'Botany'
     >>> mark.dept = 'Space Pirate'
     Traceback (most recent call last):
         ...
     AttributeError: property 'dept' of 'Immutable' object has no setter
     >>> mark.location = 'Mars'
     Traceback (most recent call last):
         ...
     AttributeError: 'Immutable' object has no attribute 'location'

3.  Saves memory.  On a 64-bit Linux build, an instance with two
attributes takes 48 bytes with ‘__slots__’ and 152 bytes without.  This
flyweight design pattern(1) likely only matters when a large number of
instances are going to be created.

4.  Improves speed.  Reading instance variables is 35% faster with
‘__slots__’ (as measured with Python 3.10 on an Apple M1 processor).

5.  Blocks tools like *note functools.cached_property(): 544. which
require an instance dictionary to function correctly:

     from functools import cached_property

     class CP:
         __slots__ = ()                          # Eliminates the instance dict

         @cached_property                        # Requires an instance dict
         def pi(self):
             return 4 * sum((-1.0)**n / (2.0*n + 1.0)
                            for n in reversed(range(100_000)))

     >>> CP().pi
     Traceback (most recent call last):
       ...
     TypeError: No '__dict__' attribute on 'CP' instance to cache 'pi' property.

It is not possible to create an exact drop-in pure Python version of
‘__slots__’ because it requires direct access to C structures and
control over object memory allocation.  However, we can build a mostly
faithful simulation where the actual C structure for slots is emulated
by a private ‘_slotvalues’ list.  Reads and writes to that private
structure are managed by member descriptors:

     null = object()

     class Member:

         def __init__(self, name, clsname, offset):
             'Emulate PyMemberDef in Include/structmember.h'
             # Also see descr_new() in Objects/descrobject.c
             self.name = name
             self.clsname = clsname
             self.offset = offset

         def __get__(self, obj, objtype=None):
             'Emulate member_get() in Objects/descrobject.c'
             # Also see PyMember_GetOne() in Python/structmember.c
             if obj is None:
                 return self
             value = obj._slotvalues[self.offset]
             if value is null:
                 raise AttributeError(self.name)
             return value

         def __set__(self, obj, value):
             'Emulate member_set() in Objects/descrobject.c'
             obj._slotvalues[self.offset] = value

         def __delete__(self, obj):
             'Emulate member_delete() in Objects/descrobject.c'
             value = obj._slotvalues[self.offset]
             if value is null:
                 raise AttributeError(self.name)
             obj._slotvalues[self.offset] = null

         def __repr__(self):
             'Emulate member_repr() in Objects/descrobject.c'
             return f'<Member {self.name!r} of {self.clsname!r}>'

The ‘type.__new__()’ method takes care of adding member objects to class
variables:

     class Type(type):
         'Simulate how the type metaclass adds member objects for slots'

         def __new__(mcls, clsname, bases, mapping, **kwargs):
             'Emulate type_new() in Objects/typeobject.c'
             # type_new() calls PyTypeReady() which calls add_methods()
             slot_names = mapping.get('slot_names', [])
             for offset, name in enumerate(slot_names):
                 mapping[name] = Member(name, clsname, offset)
             return type.__new__(mcls, clsname, bases, mapping, **kwargs)

The *note object.__new__(): 583. method takes care of creating instances
that have slots instead of an instance dictionary.  Here is a rough
simulation in pure Python:

     class Object:
         'Simulate how object.__new__() allocates memory for __slots__'

         def __new__(cls, *args, **kwargs):
             'Emulate object_new() in Objects/typeobject.c'
             inst = super().__new__(cls)
             if hasattr(cls, 'slot_names'):
                 empty_slots = [null] * len(cls.slot_names)
                 object.__setattr__(inst, '_slotvalues', empty_slots)
             return inst

         def __setattr__(self, name, value):
             'Emulate _PyObject_GenericSetAttrWithDict() Objects/object.c'
             cls = type(self)
             if hasattr(cls, 'slot_names') and name not in cls.slot_names:
                 raise AttributeError(
                     f'{cls.__name__!r} object has no attribute {name!r}'
                 )
             super().__setattr__(name, value)

         def __delattr__(self, name):
             'Emulate _PyObject_GenericSetAttrWithDict() Objects/object.c'
             cls = type(self)
             if hasattr(cls, 'slot_names') and name not in cls.slot_names:
                 raise AttributeError(
                     f'{cls.__name__!r} object has no attribute {name!r}'
                 )
             super().__delattr__(name)

To use the simulation in a real class, just inherit from ‘Object’ and
set the *note metaclass: 2136. to ‘Type’:

     class H(Object, metaclass=Type):
         'Instance variables stored in slots'

         slot_names = ['x', 'y']

         def __init__(self, x, y):
             self.x = x
             self.y = y

At this point, the metaclass has loaded member objects for 'x' and 'y':

     >>> from pprint import pp
     >>> pp(dict(vars(H)))
     {'__module__': '__main__',
      '__doc__': 'Instance variables stored in slots',
      'slot_names': ['x', 'y'],
      '__init__': <function H.__init__ at 0x7fb5d302f9d0>,
      'x': <Member 'x' of 'H'>,
      'y': <Member 'y' of 'H'>}

When instances are created, they have a ‘slot_values’ list where the
attributes are stored:

     >>> h = H(10, 20)
     >>> vars(h)
     {'_slotvalues': [10, 20]}
     >>> h.x = 55
     >>> vars(h)
     {'_slotvalues': [55, 20]}

Misspelled or unassigned attributes will raise an exception:

     >>> h.xz
     Traceback (most recent call last):
         ...
     AttributeError: 'H' object has no attribute 'xz'

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Flyweight_pattern


File: python.info,  Node: Debugging C API extensions and CPython Internals with GDB,  Next: Enum HOWTO,  Prev: Descriptor Guide,  Up: Python HOWTOs

9.5 Debugging C API extensions and CPython Internals with GDB
=============================================================

This document explains how the Python GDB extension, ‘python-gdb.py’,
can be used with the GDB debugger to debug CPython extensions and the
CPython interpreter itself.

When debugging low-level problems such as crashes or deadlocks, a
low-level debugger, such as GDB, is useful to diagnose and correct the
issue.  By default, GDB (or any of its front-ends) doesn’t support
high-level information specific to the CPython interpreter.

The ‘python-gdb.py’ extension adds CPython interpreter information to
GDB. The extension helps introspect the stack of currently executing
Python functions.  Given a Python object represented by a *note
PyObject: 33a.* pointer, the extension surfaces the type and value of
the object.

Developers who are working on CPython extensions or tinkering with parts
of CPython that are written in C can use this document to learn how to
use the ‘python-gdb.py’ extension with GDB.

     Note: This document assumes that you are familiar with the basics
     of GDB and the CPython C API. It consolidates guidance from the
     devguide(1) and the Python wiki(2).

* Menu:

* Prerequisites::
* Using the Debug build and Development mode::
* Using the python-gdb extension::
* Use with GDB commands::

   ---------- Footnotes ----------

   (1) https://devguide.python.org

   (2) https://wiki.python.org/moin/DebuggingWithGdb


File: python.info,  Node: Prerequisites,  Next: Using the Debug build and Development mode,  Up: Debugging C API extensions and CPython Internals with GDB

9.5.1 Prerequisites
-------------------

You need to have:

   - GDB 7 or later.  (For earlier versions of GDB, see ‘Misc/gdbinit’
     in the sources of Python 3.11 or earlier.)

   - GDB-compatible debugging information for Python and any extension
     you are debugging.

   - The ‘python-gdb.py’ extension.

The extension is built with Python, but might be distributed separately
or not at all.  Below, we include tips for a few common systems as
examples.  Note that even if the instructions match your system, they
might be outdated.

* Menu:

* Setup with Python built from source::
* Setup for Python from a Linux distro::


File: python.info,  Node: Setup with Python built from source,  Next: Setup for Python from a Linux distro,  Up: Prerequisites

9.5.1.1 Setup with Python built from source
...........................................

When you build CPython from source, debugging information should be
available, and the build should add a ‘python-gdb.py’ file to the root
directory of your repository.

To activate support, you must add the directory containing
‘python-gdb.py’ to GDB’s “auto-load-safe-path”.  If you haven’t done
this, recent versions of GDB will print out a warning with instructions
on how to do this.

     Note: If you do not see instructions for your version of GDB, put
     this in your configuration file (‘~/.gdbinit’ or
     ‘~/.config/gdb/gdbinit’):

          add-auto-load-safe-path /path/to/cpython

     You can also add multiple paths, separated by ‘:’.


File: python.info,  Node: Setup for Python from a Linux distro,  Prev: Setup with Python built from source,  Up: Prerequisites

9.5.1.2 Setup for Python from a Linux distro
............................................

Most Linux systems provide debug information for the system Python in a
package called ‘python-debuginfo’, ‘python-dbg’ or similar.  For
example:

   - Fedora:

               sudo dnf install gdb
               sudo dnf debuginfo-install python3

   - Ubuntu:

               sudo apt install gdb python3-dbg

On several recent Linux systems, GDB can download debugging symbols
automatically using 'debuginfod'.  However, this will not install the
‘python-gdb.py’ extension; you generally do need to install the debug
info package separately.


File: python.info,  Node: Using the Debug build and Development mode,  Next: Using the python-gdb extension,  Prev: Prerequisites,  Up: Debugging C API extensions and CPython Internals with GDB

9.5.2 Using the Debug build and Development mode
------------------------------------------------

For easier debugging, you might want to:

   - Use a *note debug build: 1f9. of Python.  (When building from
     source, use ‘configure --with-pydebug’.  On Linux distros, install
     and run a package like ‘python-debug’ or ‘python-dbg’, if
     available.)

   - Use the runtime *note development mode: 1f8. (‘-X dev’).

Both enable extra assertions and disable some optimizations.  Sometimes
this hides the bug you are trying to find, but in most cases they make
the process easier.


File: python.info,  Node: Using the python-gdb extension,  Next: Use with GDB commands,  Prev: Using the Debug build and Development mode,  Up: Debugging C API extensions and CPython Internals with GDB

9.5.3 Using the ‘python-gdb’ extension
--------------------------------------

When the extension is loaded, it provides two main features: pretty
printers for Python values, and additional commands.

* Menu:

* Pretty-printers::
* py-list::
* py-up and py-down::
* py-bt::
* py-print::
* py-locals::


File: python.info,  Node: Pretty-printers,  Next: py-list,  Up: Using the python-gdb extension

9.5.3.1 Pretty-printers
.......................

This is what a GDB backtrace looks like (truncated) when this extension
is enabled:

     #0  0x000000000041a6b1 in PyObject_Malloc (nbytes=Cannot access memory at address 0x7fffff7fefe8
     ) at Objects/obmalloc.c:748
     #1  0x000000000041b7c0 in _PyObject_DebugMallocApi (id=111 'o', nbytes=24) at Objects/obmalloc.c:1445
     #2  0x000000000041b717 in _PyObject_DebugMalloc (nbytes=24) at Objects/obmalloc.c:1412
     #3  0x000000000044060a in _PyUnicode_New (length=11) at Objects/unicodeobject.c:346
     #4  0x00000000004466aa in PyUnicodeUCS2_DecodeUTF8Stateful (s=0x5c2b8d "__lltrace__", size=11, errors=0x0, consumed=
         0x0) at Objects/unicodeobject.c:2531
     #5  0x0000000000446647 in PyUnicodeUCS2_DecodeUTF8 (s=0x5c2b8d "__lltrace__", size=11, errors=0x0)
         at Objects/unicodeobject.c:2495
     #6  0x0000000000440d1b in PyUnicodeUCS2_FromStringAndSize (u=0x5c2b8d "__lltrace__", size=11)
         at Objects/unicodeobject.c:551
     #7  0x0000000000440d94 in PyUnicodeUCS2_FromString (u=0x5c2b8d "__lltrace__") at Objects/unicodeobject.c:569
     #8  0x0000000000584abd in PyDict_GetItemString (v=
         {'Yuck': <type at remote 0xad4730>, '__builtins__': <module at remote 0x7ffff7fd5ee8>, '__file__': 'Lib/test/crashers/nasty_eq_vs_dict.py', '__package__': None, 'y': <Yuck(i=0) at remote 0xaacd80>, 'dict': {0: 0, 1: 1, 2: 2, 3: 3}, '__cached__': None, '__name__': '__main__', 'z': <Yuck(i=0) at remote 0xaace60>, '__doc__': None}, key=
         0x5c2b8d "__lltrace__") at Objects/dictobject.c:2171

Notice how the dictionary argument to ‘PyDict_GetItemString’ is
displayed as its ‘repr()’, rather than an opaque ‘PyObject *’ pointer.

The extension works by supplying a custom printing routine for values of
type ‘PyObject *’.  If you need to access lower-level details of an
object, then cast the value to a pointer of the appropriate type.  For
example:

     (gdb) p globals
     $1 = {'__builtins__': <module at remote 0x7ffff7fb1868>, '__name__':
     '__main__', 'ctypes': <module at remote 0x7ffff7f14360>, '__doc__': None,
     '__package__': None}

     (gdb) p *(PyDictObject*)globals
     $2 = {ob_refcnt = 3, ob_type = 0x3dbdf85820, ma_fill = 5, ma_used = 5,
     ma_mask = 7, ma_table = 0x63d0f8, ma_lookup = 0x3dbdc7ea70
     <lookdict_string>, ma_smalltable = {{me_hash = 7065186196740147912,
     me_key = '__builtins__', me_value = <module at remote 0x7ffff7fb1868>},
     {me_hash = -368181376027291943, me_key = '__name__',
     me_value ='__main__'}, {me_hash = 0, me_key = 0x0, me_value = 0x0},
     {me_hash = 0, me_key = 0x0, me_value = 0x0},
     {me_hash = -9177857982131165996, me_key = 'ctypes',
     me_value = <module at remote 0x7ffff7f14360>},
     {me_hash = -8518757509529533123, me_key = '__doc__', me_value = None},
     {me_hash = 0, me_key = 0x0, me_value = 0x0}, {
       me_hash = 6614918939584953775, me_key = '__package__', me_value = None}}}

Note that the pretty-printers do not actually call ‘repr()’.  For basic
types, they try to match its result closely.

An area that can be confusing is that the custom printer for some types
look a lot like GDB’s built-in printer for standard types.  For example,
the pretty-printer for a Python ‘int’ (*note PyLongObject: 58b.*) gives
a representation that is not distinguishable from one of a regular
machine-level integer:

     (gdb) p some_machine_integer
     $3 = 42

     (gdb) p some_python_integer
     $4 = 42

The internal structure can be revealed with a cast to *note
PyLongObject: 58b.*:

     (gdb) p *(PyLongObject*)some_python_integer
     $5 = {ob_base = {ob_base = {ob_refcnt = 8, ob_type = 0x3dad39f5e0}, ob_size = 1},
     ob_digit = {42}}

A similar confusion can arise with the ‘str’ type, where the output
looks a lot like gdb’s built-in printer for ‘char *’:

     (gdb) p ptr_to_python_str
     $6 = '__builtins__'

The pretty-printer for ‘str’ instances defaults to using single-quotes
(as does Python’s ‘repr’ for strings) whereas the standard printer for
‘char *’ values uses double-quotes and contains a hexadecimal address:

     (gdb) p ptr_to_char_star
     $7 = 0x6d72c0 "hello world"

Again, the implementation details can be revealed with a cast to *note
PyUnicodeObject: 797.*:

     (gdb) p *(PyUnicodeObject*)$6
     $8 = {ob_base = {ob_refcnt = 33, ob_type = 0x3dad3a95a0}, length = 12,
     str = 0x7ffff2128500, hash = 7065186196740147912, state = 1, defenc = 0x0}


File: python.info,  Node: py-list,  Next: py-up and py-down,  Prev: Pretty-printers,  Up: Using the python-gdb extension

9.5.3.2 ‘py-list’
.................

     The extension adds a ‘py-list’ command, which lists the Python
     source code (if any) for the current frame in the selected thread.
     The current line is marked with a “>”:

          (gdb) py-list
           901        if options.profile:
           902            options.profile = False
           903            profile_me()
           904            return
           905
          >906        u = UI()
           907        if not u.quit:
           908            try:
           909                gtk.main()
           910            except KeyboardInterrupt:
           911                # properly quit on a keyboard interrupt...

     Use ‘py-list START’ to list at a different line number within the
     Python source, and ‘py-list START,END’ to list a specific range of
     lines within the Python source.


File: python.info,  Node: py-up and py-down,  Next: py-bt,  Prev: py-list,  Up: Using the python-gdb extension

9.5.3.3 ‘py-up’ and ‘py-down’
.............................

     The ‘py-up’ and ‘py-down’ commands are analogous to GDB’s regular
     ‘up’ and ‘down’ commands, but try to move at the level of CPython
     frames, rather than C frames.

     GDB is not always able to read the relevant frame information,
     depending on the optimization level with which CPython was
     compiled.  Internally, the commands look for C frames that are
     executing the default frame evaluation function (that is, the core
     bytecode interpreter loop within CPython) and look up the value of
     the related ‘PyFrameObject *’.

     They emit the frame number (at the C level) within the thread.

     For example:

          (gdb) py-up
          #37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/
          gnome_sudoku/main.py, line 906, in start_game ()
              u = UI()
          (gdb) py-up
          #40 Frame 0x948e82c, for file /usr/lib/python2.6/site-packages/
          gnome_sudoku/gnome_sudoku.py, line 22, in start_game(main=<module at remote 0xb771b7f4>)
              main.start_game()
          (gdb) py-up
          Unable to find an older python frame

     so we’re at the top of the Python stack.

     The frame numbers correspond to those displayed by GDB’s standard
     ‘backtrace’ command.  The command skips C frames which are not
     executing Python code.

     Going back down:

          (gdb) py-down
          #37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/gnome_sudoku/main.py, line 906, in start_game ()
              u = UI()
          (gdb) py-down
          #34 (unable to read python frame information)
          (gdb) py-down
          #23 (unable to read python frame information)
          (gdb) py-down
          #19 (unable to read python frame information)
          (gdb) py-down
          #14 Frame 0x99262ac, for file /usr/lib/python2.6/site-packages/gnome_sudoku/game_selector.py, line 201, in run_swallowed_dialog (self=<NewOrSavedGameSelector(new_game_model=<gtk.ListStore at remote 0x98fab44>, puzzle=None, saved_games=[{'gsd.auto_fills': 0, 'tracking': {}, 'trackers': {}, 'notes': [], 'saved_at': 1270084485, 'game': '7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 0 0 0 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5\n7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 1 8 3 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5', 'gsd.impossible_hints': 0, 'timer.__absolute_start_time__': <float at remote 0x984b474>, 'gsd.hints': 0, 'timer.active_time': <float at remote 0x984b494>, 'timer.total_time': <float at remote 0x984b464>}], dialog=<gtk.Dialog at remote 0x98faaa4>, saved_game_model=<gtk.ListStore at remote 0x98fad24>, sudoku_maker=<SudokuMaker(terminated=False, played=[], batch_siz...(truncated)
                      swallower.run_dialog(self.dialog)
          (gdb) py-down
          #11 Frame 0x9aead74, for file /usr/lib/python2.6/site-packages/gnome_sudoku/dialog_swallower.py, line 48, in run_dialog (self=<SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>, main_page=0) at remote 0x98fa6e4>, d=<gtk.Dialog at remote 0x98faaa4>)
                      gtk.main()
          (gdb) py-down
          #8 (unable to read python frame information)
          (gdb) py-down
          Unable to find a newer python frame

     and we’re at the bottom of the Python stack.

     Note that in Python 3.12 and newer, the same C stack frame can be
     used for multiple Python stack frames.  This means that ‘py-up’ and
     ‘py-down’ may move multiple Python frames at once.  For example:

          (gdb) py-up
          #6 Frame 0x7ffff7fb62b0, for file /tmp/rec.py, line 5, in recursive_function (n=0)
             time.sleep(5)
          #6 Frame 0x7ffff7fb6240, for file /tmp/rec.py, line 7, in recursive_function (n=1)
             recursive_function(n-1)
          #6 Frame 0x7ffff7fb61d0, for file /tmp/rec.py, line 7, in recursive_function (n=2)
             recursive_function(n-1)
          #6 Frame 0x7ffff7fb6160, for file /tmp/rec.py, line 7, in recursive_function (n=3)
             recursive_function(n-1)
          #6 Frame 0x7ffff7fb60f0, for file /tmp/rec.py, line 7, in recursive_function (n=4)
             recursive_function(n-1)
          #6 Frame 0x7ffff7fb6080, for file /tmp/rec.py, line 7, in recursive_function (n=5)
             recursive_function(n-1)
          #6 Frame 0x7ffff7fb6020, for file /tmp/rec.py, line 9, in <module> ()
             recursive_function(5)
          (gdb) py-up
          Unable to find an older python frame


File: python.info,  Node: py-bt,  Next: py-print,  Prev: py-up and py-down,  Up: Using the python-gdb extension

9.5.3.4 ‘py-bt’
...............

     The ‘py-bt’ command attempts to display a Python-level backtrace of
     the current thread.

     For example:

          (gdb) py-bt
          #8 (unable to read python frame information)
          #11 Frame 0x9aead74, for file /usr/lib/python2.6/site-packages/gnome_sudoku/dialog_swallower.py, line 48, in run_dialog (self=<SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>, main_page=0) at remote 0x98fa6e4>, d=<gtk.Dialog at remote 0x98faaa4>)
                      gtk.main()
          #14 Frame 0x99262ac, for file /usr/lib/python2.6/site-packages/gnome_sudoku/game_selector.py, line 201, in run_swallowed_dialog (self=<NewOrSavedGameSelector(new_game_model=<gtk.ListStore at remote 0x98fab44>, puzzle=None, saved_games=[{'gsd.auto_fills': 0, 'tracking': {}, 'trackers': {}, 'notes': [], 'saved_at': 1270084485, 'game': '7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 0 0 0 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5\n7 8 0 0 0 0 0 5 6 0 0 9 0 8 0 1 0 0 0 4 6 0 0 0 0 7 0 6 5 1 8 3 4 7 9 2 0 0 0 9 0 1 0 0 0 3 9 7 6 0 0 0 1 8 0 6 0 0 0 0 2 8 0 0 0 5 0 4 0 6 0 0 2 1 0 0 0 0 0 4 5', 'gsd.impossible_hints': 0, 'timer.__absolute_start_time__': <float at remote 0x984b474>, 'gsd.hints': 0, 'timer.active_time': <float at remote 0x984b494>, 'timer.total_time': <float at remote 0x984b464>}], dialog=<gtk.Dialog at remote 0x98faaa4>, saved_game_model=<gtk.ListStore at remote 0x98fad24>, sudoku_maker=<SudokuMaker(terminated=False, played=[], batch_siz...(truncated)
                      swallower.run_dialog(self.dialog)
          #19 (unable to read python frame information)
          #23 (unable to read python frame information)
          #34 (unable to read python frame information)
          #37 Frame 0x9420b04, for file /usr/lib/python2.6/site-packages/gnome_sudoku/main.py, line 906, in start_game ()
              u = UI()
          #40 Frame 0x948e82c, for file /usr/lib/python2.6/site-packages/gnome_sudoku/gnome_sudoku.py, line 22, in start_game (main=<module at remote 0xb771b7f4>)
              main.start_game()

     The frame numbers correspond to those displayed by GDB’s standard
     ‘backtrace’ command.


File: python.info,  Node: py-print,  Next: py-locals,  Prev: py-bt,  Up: Using the python-gdb extension

9.5.3.5 ‘py-print’
..................

     The ‘py-print’ command looks up a Python name and tries to print
     it.  It looks in locals within the current thread, then globals,
     then finally builtins:

          (gdb) py-print self
          local 'self' = <SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>,
          main_page=0) at remote 0x98fa6e4>
          (gdb) py-print __name__
          global '__name__' = 'gnome_sudoku.dialog_swallower'
          (gdb) py-print len
          builtin 'len' = <built-in function len>
          (gdb) py-print scarlet_pimpernel
          'scarlet_pimpernel' not found

     If the current C frame corresponds to multiple Python frames,
     ‘py-print’ only considers the first one.


File: python.info,  Node: py-locals,  Prev: py-print,  Up: Using the python-gdb extension

9.5.3.6 ‘py-locals’
...................

     The ‘py-locals’ command looks up all Python locals within the
     current Python frame in the selected thread, and prints their
     representations:

          (gdb) py-locals
          self = <SwappableArea(running=<gtk.Dialog at remote 0x98faaa4>,
          main_page=0) at remote 0x98fa6e4>
          d = <gtk.Dialog at remote 0x98faaa4>

     If the current C frame corresponds to multiple Python frames,
     locals from all of them will be shown:

          (gdb) py-locals
          Locals for recursive_function
          n = 0
          Locals for recursive_function
          n = 1
          Locals for recursive_function
          n = 2
          Locals for recursive_function
          n = 3
          Locals for recursive_function
          n = 4
          Locals for recursive_function
          n = 5
          Locals for <module>


File: python.info,  Node: Use with GDB commands,  Prev: Using the python-gdb extension,  Up: Debugging C API extensions and CPython Internals with GDB

9.5.4 Use with GDB commands
---------------------------

The extension commands complement GDB’s built-in commands.  For example,
you can use a frame numbers shown by ‘py-bt’ with the ‘frame’ command to
go a specific frame within the selected thread, like this:

     (gdb) py-bt
     (output snipped)
     #68 Frame 0xaa4560, for file Lib/test/regrtest.py, line 1548, in <module> ()
             main()
     (gdb) frame 68
     #68 0x00000000004cd1e6 in PyEval_EvalFrameEx (f=Frame 0xaa4560, for file Lib/test/regrtest.py, line 1548, in <module> (), throwflag=0) at Python/ceval.c:2665
     2665                            x = call_function(&sp, oparg);
     (gdb) py-list
     1543        # Run the tests in a context manager that temporary changes the CWD to a
     1544        # temporary and writable directory. If it's not possible to create or
     1545        # change the CWD, the original CWD will be used. The original CWD is
     1546        # available from test_support.SAVEDCWD.
     1547        with test_support.temp_cwd(TESTCWD, quiet=True):
     >1548            main()

The ‘info threads’ command will give you a list of the threads within
the process, and you can use the ‘thread’ command to select a different
one:

     (gdb) info threads
       105 Thread 0x7fffefa18710 (LWP 10260)  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:86
       104 Thread 0x7fffdf5fe710 (LWP 10259)  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:86
     * 1 Thread 0x7ffff7fe2700 (LWP 10145)  0x00000038e46d73e3 in select () at ../sysdeps/unix/syscall-template.S:82

You can use ‘thread apply all COMMAND’ or (‘t a a COMMAND’ for short) to
run a command on all threads.  With ‘py-bt’, this lets you see what
every thread is doing at the Python level:

     (gdb) t a a py-bt

     Thread 105 (Thread 0x7fffefa18710 (LWP 10260)):
     #5 Frame 0x7fffd00019d0, for file /home/david/coding/python-svn/Lib/threading.py, line 155, in _acquire_restore (self=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, count_owner=(1, 140737213728528), count=1, owner=140737213728528)
             self.__block.acquire()
     #8 Frame 0x7fffac001640, for file /home/david/coding/python-svn/Lib/threading.py, line 269, in wait (self=<_Condition(_Condition__lock=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, acquire=<instancemethod at remote 0xd80260>, _is_owned=<instancemethod at remote 0xd80160>, _release_save=<instancemethod at remote 0xd803e0>, release=<instancemethod at remote 0xd802e0>, _acquire_restore=<instancemethod at remote 0xd7ee60>, _Verbose__verbose=False, _Condition__waiters=[]) at remote 0xd7fd10>, timeout=None, waiter=<thread.lock at remote 0x858a90>, saved_state=(1, 140737213728528))
                 self._acquire_restore(saved_state)
     #12 Frame 0x7fffb8001a10, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 348, in f ()
                 cond.wait()
     #16 Frame 0x7fffb8001c40, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 37, in task (tid=140737213728528)
                     f()

     Thread 104 (Thread 0x7fffdf5fe710 (LWP 10259)):
     #5 Frame 0x7fffe4001580, for file /home/david/coding/python-svn/Lib/threading.py, line 155, in _acquire_restore (self=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, count_owner=(1, 140736940992272), count=1, owner=140736940992272)
             self.__block.acquire()
     #8 Frame 0x7fffc8002090, for file /home/david/coding/python-svn/Lib/threading.py, line 269, in wait (self=<_Condition(_Condition__lock=<_RLock(_Verbose__verbose=False, _RLock__owner=140737354016512, _RLock__block=<thread.lock at remote 0x858770>, _RLock__count=1) at remote 0xd7ff40>, acquire=<instancemethod at remote 0xd80260>, _is_owned=<instancemethod at remote 0xd80160>, _release_save=<instancemethod at remote 0xd803e0>, release=<instancemethod at remote 0xd802e0>, _acquire_restore=<instancemethod at remote 0xd7ee60>, _Verbose__verbose=False, _Condition__waiters=[]) at remote 0xd7fd10>, timeout=None, waiter=<thread.lock at remote 0x858860>, saved_state=(1, 140736940992272))
                 self._acquire_restore(saved_state)
     #12 Frame 0x7fffac001c90, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 348, in f ()
                 cond.wait()
     #16 Frame 0x7fffac0011c0, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 37, in task (tid=140736940992272)
                     f()

     Thread 1 (Thread 0x7ffff7fe2700 (LWP 10145)):
     #5 Frame 0xcb5380, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 16, in _wait ()
         time.sleep(0.01)
     #8 Frame 0x7fffd00024a0, for file /home/david/coding/python-svn/Lib/test/lock_tests.py, line 378, in _check_notify (self=<ConditionTests(_testMethodName='test_notify', _resultForDoCleanups=<TestResult(_original_stdout=<cStringIO.StringO at remote 0xc191e0>, skipped=[], _mirrorOutput=False, testsRun=39, buffer=False, _original_stderr=<file at remote 0x7ffff7fc6340>, _stdout_buffer=<cStringIO.StringO at remote 0xc9c7f8>, _stderr_buffer=<cStringIO.StringO at remote 0xc9c790>, _moduleSetUpFailed=False, expectedFailures=[], errors=[], _previousTestClass=<type at remote 0x928310>, unexpectedSuccesses=[], failures=[], shouldStop=False, failfast=False) at remote 0xc185a0>, _threads=(0,), _cleanups=[], _type_equality_funcs={<type at remote 0x7eba00>: <instancemethod at remote 0xd750e0>, <type at remote 0x7e7820>: <instancemethod at remote 0xd75160>, <type at remote 0x7e30e0>: <instancemethod at remote 0xd75060>, <type at remote 0x7e7d20>: <instancemethod at remote 0xd751e0>, <type at remote 0x7f19e0...(truncated)
             _wait()


File: python.info,  Node: Enum HOWTO,  Next: Functional Programming HOWTO,  Prev: Debugging C API extensions and CPython Internals with GDB,  Up: Python HOWTOs

9.6 Enum HOWTO
==============

An *note Enum: 633. is a set of symbolic names bound to unique values.
They are similar to global variables, but they offer a more useful *note
repr(): 803, grouping, type-safety, and a few other features.

They are most useful when you have a variable that can take one of a
limited selection of values.  For example, the days of the week:

     >>> from enum import Enum
     >>> class Weekday(Enum):
     ...     MONDAY = 1
     ...     TUESDAY = 2
     ...     WEDNESDAY = 3
     ...     THURSDAY = 4
     ...     FRIDAY = 5
     ...     SATURDAY = 6
     ...     SUNDAY = 7

Or perhaps the RGB primary colors:

     >>> from enum import Enum
     >>> class Color(Enum):
     ...     RED = 1
     ...     GREEN = 2
     ...     BLUE = 3

As you can see, creating an *note Enum: 633. is as simple as writing a
class that inherits from ‘Enum’ itself.

     Note: Case of Enum Members

     Because Enums are used to represent constants, and to help avoid
     issues with name clashes between mixin-class methods/attributes and
     enum names, we strongly recommend using UPPER_CASE names for
     members, and will be using that style in our examples.

Depending on the nature of the enum a member’s value may or may not be
important, but either way that value can be used to get the
corresponding member:

     >>> Weekday(3)
     <Weekday.WEDNESDAY: 3>

As you can see, the ‘repr()’ of a member shows the enum name, the member
name, and the value.  The ‘str()’ of a member shows only the enum name
and member name:

     >>> print(Weekday.THURSDAY)
     Weekday.THURSDAY

The 'type' of an enumeration member is the enum it belongs to:

     >>> type(Weekday.MONDAY)
     <enum 'Weekday'>
     >>> isinstance(Weekday.FRIDAY, Weekday)
     True

Enum members have an attribute that contains just their ‘name’:

     >>> print(Weekday.TUESDAY.name)
     TUESDAY

Likewise, they have an attribute for their ‘value’:

     >>> Weekday.WEDNESDAY.value
     3

Unlike many languages that treat enumerations solely as name/value
pairs, Python Enums can have behavior added.  For example, *note
datetime.date: 1cd. has two methods for returning the weekday: *note
weekday(): 260d. and *note isoweekday(): 260e.  The difference is that
one of them counts from 0-6 and the other from 1-7.  Rather than keep
track of that ourselves we can add a method to the ‘Weekday’ enum to
extract the day from the ‘date’ instance and return the matching enum
member:

     @classmethod
     def from_date(cls, date):
         return cls(date.isoweekday())

The complete ‘Weekday’ enum now looks like this:

     >>> class Weekday(Enum):
     ...     MONDAY = 1
     ...     TUESDAY = 2
     ...     WEDNESDAY = 3
     ...     THURSDAY = 4
     ...     FRIDAY = 5
     ...     SATURDAY = 6
     ...     SUNDAY = 7
     ...     #
     ...     @classmethod
     ...     def from_date(cls, date):
     ...         return cls(date.isoweekday())

Now we can find out what today is!  Observe:

     >>> import datetime as dt
     >>> Weekday.from_date(dt.date.today())
     <Weekday.TUESDAY: 2>

Of course, if you’re reading this on some other day, you’ll see that day
instead.

This ‘Weekday’ enum is great if our variable only needs one day, but
what if we need several?  Maybe we’re writing a function to plot chores
during a week, and don’t want to use a *note list: 614. – we could use a
different type of *note Enum: 633.:

     >>> from enum import Flag
     >>> class Weekday(Flag):
     ...     MONDAY = 1
     ...     TUESDAY = 2
     ...     WEDNESDAY = 4
     ...     THURSDAY = 8
     ...     FRIDAY = 16
     ...     SATURDAY = 32
     ...     SUNDAY = 64

We’ve changed two things: we’re inherited from *note Flag: 626, and the
values are all powers of 2.

Just like the original ‘Weekday’ enum above, we can have a single
selection:

     >>> first_week_day = Weekday.MONDAY
     >>> first_week_day
     <Weekday.MONDAY: 1>

But *note Flag: 626. also allows us to combine several members into a
single variable:

     >>> weekend = Weekday.SATURDAY | Weekday.SUNDAY
     >>> weekend
     <Weekday.SATURDAY|SUNDAY: 96>

You can even iterate over a *note Flag: 626. variable:

     >>> for day in weekend:
     ...     print(day)
     Weekday.SATURDAY
     Weekday.SUNDAY

Okay, let’s get some chores set up:

     >>> chores_for_ethan = {
     ...     'feed the cat': Weekday.MONDAY | Weekday.WEDNESDAY | Weekday.FRIDAY,
     ...     'do the dishes': Weekday.TUESDAY | Weekday.THURSDAY,
     ...     'answer SO questions': Weekday.SATURDAY,
     ...     }

And a function to display the chores for a given day:

     >>> def show_chores(chores, day):
     ...     for chore, days in chores.items():
     ...         if day in days:
     ...             print(chore)
     ...
     >>> show_chores(chores_for_ethan, Weekday.SATURDAY)
     answer SO questions

In cases where the actual values of the members do not matter, you can
save yourself some work and use *note auto(): cc2. for the values:

     >>> from enum import auto
     >>> class Weekday(Flag):
     ...     MONDAY = auto()
     ...     TUESDAY = auto()
     ...     WEDNESDAY = auto()
     ...     THURSDAY = auto()
     ...     FRIDAY = auto()
     ...     SATURDAY = auto()
     ...     SUNDAY = auto()
     ...     WEEKEND = SATURDAY | SUNDAY

* Menu:

* Programmatic access to enumeration members and their attributes::
* Duplicating enum members and values::
* Ensuring unique enumeration values::
* Using automatic values::
* Iteration: Iteration<2>.
* Comparisons: Comparisons<3>.
* Allowed members and attributes of enumerations::
* Restricted Enum subclassing::
* Dataclass support::
* Pickling::
* Functional API: Functional API<3>.
* Derived Enumerations::
* When to use __new__() vs. __init__(): When to use __new__ vs __init__.
* Finer Points::
* How are Enums and Flags different?::
* Enum Cookbook::
* Subclassing EnumType::


File: python.info,  Node: Programmatic access to enumeration members and their attributes,  Next: Duplicating enum members and values,  Up: Enum HOWTO

9.6.1 Programmatic access to enumeration members and their attributes
---------------------------------------------------------------------

Sometimes it’s useful to access members in enumerations programmatically
(i.e.  situations where ‘Color.RED’ won’t do because the exact color is
not known at program-writing time).  ‘Enum’ allows such access:

     >>> Color(1)
     <Color.RED: 1>
     >>> Color(3)
     <Color.BLUE: 3>

If you want to access enum members by 'name', use item access:

     >>> Color['RED']
     <Color.RED: 1>
     >>> Color['GREEN']
     <Color.GREEN: 2>

If you have an enum member and need its ‘name’ or ‘value’:

     >>> member = Color.RED
     >>> member.name
     'RED'
     >>> member.value
     1


File: python.info,  Node: Duplicating enum members and values,  Next: Ensuring unique enumeration values,  Prev: Programmatic access to enumeration members and their attributes,  Up: Enum HOWTO

9.6.2 Duplicating enum members and values
-----------------------------------------

Having two enum members with the same name is invalid:

     >>> class Shape(Enum):
     ...     SQUARE = 2
     ...     SQUARE = 3
     ...
     Traceback (most recent call last):
     ...
     TypeError: 'SQUARE' already defined as 2

However, an enum member can have other names associated with it.  Given
two entries ‘A’ and ‘B’ with the same value (and ‘A’ defined first), ‘B’
is an alias for the member ‘A’.  By-value lookup of the value of ‘A’
will return the member ‘A’.  By-name lookup of ‘A’ will return the
member ‘A’.  By-name lookup of ‘B’ will also return the member ‘A’:

     >>> class Shape(Enum):
     ...     SQUARE = 2
     ...     DIAMOND = 1
     ...     CIRCLE = 3
     ...     ALIAS_FOR_SQUARE = 2
     ...
     >>> Shape.SQUARE
     <Shape.SQUARE: 2>
     >>> Shape.ALIAS_FOR_SQUARE
     <Shape.SQUARE: 2>
     >>> Shape(2)
     <Shape.SQUARE: 2>

     Note: Attempting to create a member with the same name as an
     already defined attribute (another member, a method, etc.)  or
     attempting to create an attribute with the same name as a member is
     not allowed.


File: python.info,  Node: Ensuring unique enumeration values,  Next: Using automatic values,  Prev: Duplicating enum members and values,  Up: Enum HOWTO

9.6.3 Ensuring unique enumeration values
----------------------------------------

By default, enumerations allow multiple names as aliases for the same
value.  When this behavior isn’t desired, you can use the *note
unique(): 2779. decorator:

     >>> from enum import Enum, unique
     >>> @unique
     ... class Mistake(Enum):
     ...     ONE = 1
     ...     TWO = 2
     ...     THREE = 3
     ...     FOUR = 3
     ...
     Traceback (most recent call last):
     ...
     ValueError: duplicate values found in <enum 'Mistake'>: FOUR -> THREE


File: python.info,  Node: Using automatic values,  Next: Iteration<2>,  Prev: Ensuring unique enumeration values,  Up: Enum HOWTO

9.6.4 Using automatic values
----------------------------

If the exact value is unimportant you can use *note auto: cc2.:

     >>> from enum import Enum, auto
     >>> class Color(Enum):
     ...     RED = auto()
     ...     BLUE = auto()
     ...     GREEN = auto()
     ...
     >>> [member.value for member in Color]
     [1, 2, 3]

The values are chosen by *note _generate_next_value_(): 278d, which can
be overridden:

     >>> class AutoName(Enum):
     ...     @staticmethod
     ...     def _generate_next_value_(name, start, count, last_values):
     ...         return name
     ...
     >>> class Ordinal(AutoName):
     ...     NORTH = auto()
     ...     SOUTH = auto()
     ...     EAST = auto()
     ...     WEST = auto()
     ...
     >>> [member.value for member in Ordinal]
     ['NORTH', 'SOUTH', 'EAST', 'WEST']

     Note: The *note _generate_next_value_(): 278d. method must be
     defined before any members.


File: python.info,  Node: Iteration<2>,  Next: Comparisons<3>,  Prev: Using automatic values,  Up: Enum HOWTO

9.6.5 Iteration
---------------

Iterating over the members of an enum does not provide the aliases:

     >>> list(Shape)
     [<Shape.SQUARE: 2>, <Shape.DIAMOND: 1>, <Shape.CIRCLE: 3>]
     >>> list(Weekday)
     [<Weekday.MONDAY: 1>, <Weekday.TUESDAY: 2>, <Weekday.WEDNESDAY: 4>, <Weekday.THURSDAY: 8>, <Weekday.FRIDAY: 16>, <Weekday.SATURDAY: 32>, <Weekday.SUNDAY: 64>]

Note that the aliases ‘Shape.ALIAS_FOR_SQUARE’ and ‘Weekday.WEEKEND’
aren’t shown.

The special attribute ‘__members__’ is a read-only ordered mapping of
names to members.  It includes all names defined in the enumeration,
including the aliases:

     >>> for name, member in Shape.__members__.items():
     ...     name, member
     ...
     ('SQUARE', <Shape.SQUARE: 2>)
     ('DIAMOND', <Shape.DIAMOND: 1>)
     ('CIRCLE', <Shape.CIRCLE: 3>)
     ('ALIAS_FOR_SQUARE', <Shape.SQUARE: 2>)

The ‘__members__’ attribute can be used for detailed programmatic access
to the enumeration members.  For example, finding all the aliases:

     >>> [name for name, member in Shape.__members__.items() if member.name != name]
     ['ALIAS_FOR_SQUARE']

     Note: Aliases for flags include values with multiple flags set,
     such as ‘3’, and no flags set, i.e.  ‘0’.


File: python.info,  Node: Comparisons<3>,  Next: Allowed members and attributes of enumerations,  Prev: Iteration<2>,  Up: Enum HOWTO

9.6.6 Comparisons
-----------------

Enumeration members are compared by identity:

     >>> Color.RED is Color.RED
     True
     >>> Color.RED is Color.BLUE
     False
     >>> Color.RED is not Color.BLUE
     True

Ordered comparisons between enumeration values are 'not' supported.
Enum members are not integers (but see *note IntEnum: 5377. below):

     >>> Color.RED < Color.BLUE
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: '<' not supported between instances of 'Color' and 'Color'

Equality comparisons are defined though:

     >>> Color.BLUE == Color.RED
     False
     >>> Color.BLUE != Color.RED
     True
     >>> Color.BLUE == Color.BLUE
     True

Comparisons against non-enumeration values will always compare not equal
(again, *note IntEnum: d06. was explicitly designed to behave
differently, see below):

     >>> Color.BLUE == 2
     False

     Warning: It is possible to reload modules – if a reloaded module
     contains enums, they will be recreated, and the new members may not
     compare identical/equal to the original members.


File: python.info,  Node: Allowed members and attributes of enumerations,  Next: Restricted Enum subclassing,  Prev: Comparisons<3>,  Up: Enum HOWTO

9.6.7 Allowed members and attributes of enumerations
----------------------------------------------------

Most of the examples above use integers for enumeration values.  Using
integers is short and handy (and provided by default by the *note
Functional API: 5379.), but not strictly enforced.  In the vast majority
of use-cases, one doesn’t care what the actual value of an enumeration
is.  But if the value 'is' important, enumerations can have arbitrary
values.

Enumerations are Python classes, and can have methods and special
methods as usual.  If we have this enumeration:

     >>> class Mood(Enum):
     ...     FUNKY = 1
     ...     HAPPY = 3
     ...
     ...     def describe(self):
     ...         # self is the member here
     ...         return self.name, self.value
     ...
     ...     def __str__(self):
     ...         return 'my custom str! {0}'.format(self.value)
     ...
     ...     @classmethod
     ...     def favorite_mood(cls):
     ...         # cls here is the enumeration
     ...         return cls.HAPPY
     ...

Then:

     >>> Mood.favorite_mood()
     <Mood.HAPPY: 3>
     >>> Mood.HAPPY.describe()
     ('HAPPY', 3)
     >>> str(Mood.FUNKY)
     'my custom str! 1'

The rules for what is allowed are as follows: names that start and end
with a single underscore are reserved by enum and cannot be used; all
other attributes defined within an enumeration will become members of
this enumeration, with the exception of special methods (*note
__str__(): 620, *note __add__(): 2145, etc.), descriptors (methods are
also descriptors), and variable names listed in *note _ignore_: 278b.

Note: if your enumeration defines *note __new__(): 583. and/or *note
__init__(): 6b3, any value(s) given to the enum member will be passed
into those methods.  See *note Planet: 537a. for an example.

     Note: The *note __new__(): 583. method, if defined, is used during
     creation of the Enum members; it is then replaced by Enum’s
     ‘__new__()’ which is used after class creation for lookup of
     existing members.  See *note When to use __new__() vs.  __init__():
     537b. for more details.


File: python.info,  Node: Restricted Enum subclassing,  Next: Dataclass support,  Prev: Allowed members and attributes of enumerations,  Up: Enum HOWTO

9.6.8 Restricted Enum subclassing
---------------------------------

A new *note Enum: 633. class must have one base enum class, up to one
concrete data type, and as many *note object: a9b.-based mixin classes
as needed.  The order of these base classes is:

     class EnumName([mix-in, ...,] [data-type,] base-enum):
         pass

Also, subclassing an enumeration is allowed only if the enumeration does
not define any members.  So this is forbidden:

     >>> class MoreColor(Color):
     ...     PINK = 17
     ...
     Traceback (most recent call last):
     ...
     TypeError: <enum 'MoreColor'> cannot extend <enum 'Color'>

But this is allowed:

     >>> class Foo(Enum):
     ...     def some_behavior(self):
     ...         pass
     ...
     >>> class Bar(Foo):
     ...     HAPPY = 1
     ...     SAD = 2
     ...

Allowing subclassing of enums that define members would lead to a
violation of some important invariants of types and instances.  On the
other hand, it makes sense to allow sharing some common behavior between
a group of enumerations.  (See *note OrderedEnum: 537d. for an example.)


File: python.info,  Node: Dataclass support,  Next: Pickling,  Prev: Restricted Enum subclassing,  Up: Enum HOWTO

9.6.9 Dataclass support
-----------------------

When inheriting from a *note dataclass: 1cb, the *note __repr__(): 189d.
omits the inherited class’ name.  For example:

     >>> from dataclasses import dataclass, field
     >>> @dataclass
     ... class CreatureDataMixin:
     ...     size: str
     ...     legs: int
     ...     tail: bool = field(repr=False, default=True)
     ...
     >>> class Creature(CreatureDataMixin, Enum):
     ...     BEETLE = 'small', 6
     ...     DOG = 'medium', 4
     ...
     >>> Creature.DOG
     <Creature.DOG: size='medium', legs=4>

Use the *note dataclass(): 1cb. argument ‘repr=False’ to use the
standard *note repr(): 803.

Changed in version 3.12: Only the dataclass fields are shown in the
value area, not the dataclass’ name.

     Note: Adding *note dataclass(): 1cb. decorator to *note Enum: 633.
     and its subclasses is not supported.  It will not raise any errors,
     but it will produce very strange results at runtime, such as
     members being equal to each other:

          >>> @dataclass               # don't do this: it does not make any sense
          ... class Color(Enum):
          ...    RED = 1
          ...    BLUE = 2
          ...
          >>> Color.RED is Color.BLUE
          False
          >>> Color.RED == Color.BLUE  # problem is here: they should not be equal
          True


File: python.info,  Node: Pickling,  Next: Functional API<3>,  Prev: Dataclass support,  Up: Enum HOWTO

9.6.10 Pickling
---------------

Enumerations can be pickled and unpickled:

     >>> from test.test_enum import Fruit
     >>> from pickle import dumps, loads
     >>> Fruit.TOMATO is loads(dumps(Fruit.TOMATO))
     True

The usual restrictions for pickling apply: picklable enums must be
defined in the top level of a module, since unpickling requires them to
be importable from that module.

     Note: With pickle protocol version 4 it is possible to easily
     pickle enums nested in other classes.

It is possible to modify how enum members are pickled/unpickled by
defining *note __reduce_ex__(): 16bf. in the enumeration class.  The
default method is by-value, but enums with complicated values may want
to use by-name:

     >>> import enum
     >>> class MyEnum(enum.Enum):
     ...     __reduce_ex__ = enum.pickle_by_enum_name

     Note: Using by-name for flags is not recommended, as unnamed
     aliases will not unpickle.


File: python.info,  Node: Functional API<3>,  Next: Derived Enumerations,  Prev: Pickling,  Up: Enum HOWTO

9.6.11 Functional API
---------------------

The *note Enum: 633. class is callable, providing the following
functional API:

     >>> Animal = Enum('Animal', 'ANT BEE CAT DOG')
     >>> Animal
     <enum 'Animal'>
     >>> Animal.ANT
     <Animal.ANT: 1>
     >>> list(Animal)
     [<Animal.ANT: 1>, <Animal.BEE: 2>, <Animal.CAT: 3>, <Animal.DOG: 4>]

The semantics of this API resemble *note namedtuple: 1ca.  The first
argument of the call to *note Enum: 633. is the name of the enumeration.

The second argument is the 'source' of enumeration member names.  It can
be a whitespace-separated string of names, a sequence of names, a
sequence of 2-tuples with key/value pairs, or a mapping (e.g.
dictionary) of names to values.  The last two options enable assigning
arbitrary values to enumerations; the others auto-assign increasing
integers starting with 1 (use the ‘start’ parameter to specify a
different starting value).  A new class derived from *note Enum: 633. is
returned.  In other words, the above assignment to ‘Animal’ is
equivalent to:

     >>> class Animal(Enum):
     ...     ANT = 1
     ...     BEE = 2
     ...     CAT = 3
     ...     DOG = 4
     ...

The reason for defaulting to ‘1’ as the starting number and not ‘0’ is
that ‘0’ is ‘False’ in a boolean sense, but by default enum members all
evaluate to ‘True’.

Pickling enums created with the functional API can be tricky as frame
stack implementation details are used to try and figure out which module
the enumeration is being created in (e.g.  it will fail if you use a
utility function in a separate module, and also may not work on
IronPython or Jython).  The solution is to specify the module name
explicitly as follows:

     >>> Animal = Enum('Animal', 'ANT BEE CAT DOG', module=__name__)

     Warning: If ‘module’ is not supplied, and Enum cannot determine
     what it is, the new Enum members will not be unpicklable; to keep
     errors closer to the source, pickling will be disabled.

The new pickle protocol 4 also, in some circumstances, relies on *note
__qualname__: 20d5. being set to the location where pickle will be able
to find the class.  For example, if the class was made available in
class SomeData in the global scope:

     >>> Animal = Enum('Animal', 'ANT BEE CAT DOG', qualname='SomeData.Animal')

The complete signature is:

     Enum(
         value='NewEnumName',
         names=<...>,
         *,
         module='...',
         qualname='...',
         type=<mixed-in class>,
         start=1,
         )

   * 'value': What the new enum class will record as its name.

   * 'names': The enum members.  This can be a whitespace- or
     comma-separated string (values will start at 1 unless otherwise
     specified):

          'RED GREEN BLUE' | 'RED,GREEN,BLUE' | 'RED, GREEN, BLUE'

     or an iterator of names:

          ['RED', 'GREEN', 'BLUE']

     or an iterator of (name, value) pairs:

          [('CYAN', 4), ('MAGENTA', 5), ('YELLOW', 6)]

     or a mapping:

          {'CHARTREUSE': 7, 'SEA_GREEN': 11, 'ROSEMARY': 42}

   * 'module': name of module where new enum class can be found.

   * 'qualname': where in module new enum class can be found.

   * 'type': type to mix in to new enum class.

   * 'start': number to start counting at if only names are passed in.

Changed in version 3.5: The 'start' parameter was added.


File: python.info,  Node: Derived Enumerations,  Next: When to use __new__ vs __init__,  Prev: Functional API<3>,  Up: Enum HOWTO

9.6.12 Derived Enumerations
---------------------------

* Menu:

* IntEnum::
* StrEnum::
* IntFlag::
* Flag::
* Others: Others<2>.


File: python.info,  Node: IntEnum,  Next: StrEnum,  Up: Derived Enumerations

9.6.12.1 IntEnum
................

The first variation of *note Enum: 633. that is provided is also a
subclass of *note int: 257.  Members of an *note IntEnum: d06. can be
compared to integers; by extension, integer enumerations of different
types can also be compared to each other:

     >>> from enum import IntEnum
     >>> class Shape(IntEnum):
     ...     CIRCLE = 1
     ...     SQUARE = 2
     ...
     >>> class Request(IntEnum):
     ...     POST = 1
     ...     GET = 2
     ...
     >>> Shape == 1
     False
     >>> Shape.CIRCLE == 1
     True
     >>> Shape.CIRCLE == Request.POST
     True

However, they still can’t be compared to standard *note Enum: 633.
enumerations:

     >>> class Shape(IntEnum):
     ...     CIRCLE = 1
     ...     SQUARE = 2
     ...
     >>> class Color(Enum):
     ...     RED = 1
     ...     GREEN = 2
     ...
     >>> Shape.CIRCLE == Color.RED
     False

*note IntEnum: d06. values behave like integers in other ways you’d
expect:

     >>> int(Shape.CIRCLE)
     1
     >>> ['a', 'b', 'c'][Shape.CIRCLE]
     'b'
     >>> [i for i in range(Shape.SQUARE)]
     [0, 1]


File: python.info,  Node: StrEnum,  Next: IntFlag,  Prev: IntEnum,  Up: Derived Enumerations

9.6.12.2 StrEnum
................

The second variation of *note Enum: 633. that is provided is also a
subclass of *note str: 44f.  Members of a *note StrEnum: 61d. can be
compared to strings; by extension, string enumerations of different
types can also be compared to each other.

Added in version 3.11.


File: python.info,  Node: IntFlag,  Next: Flag,  Prev: StrEnum,  Up: Derived Enumerations

9.6.12.3 IntFlag
................

The next variation of *note Enum: 633. provided, *note IntFlag: cc1, is
also based on *note int: 257.  The difference being ‘IntFlag’ members
can be combined using the bitwise operators (&, |, ^, ~) and the result
is still an ‘IntFlag’ member, if possible.  Like *note IntEnum: d06,
‘IntFlag’ members are also integers and can be used wherever an ‘int’ is
used.

     Note: Any operation on an *note IntFlag: cc1. member besides the
     bit-wise operations will lose the ‘IntFlag’ membership.

     Bit-wise operations that result in invalid *note IntFlag: cc1.
     values will lose the ‘IntFlag’ membership.  See *note FlagBoundary:
     627. for details.

Added in version 3.6.

Changed in version 3.11.

Sample *note IntFlag: cc1. class:

     >>> from enum import IntFlag
     >>> class Perm(IntFlag):
     ...     R = 4
     ...     W = 2
     ...     X = 1
     ...
     >>> Perm.R | Perm.W
     <Perm.R|W: 6>
     >>> Perm.R + Perm.W
     6
     >>> RW = Perm.R | Perm.W
     >>> Perm.R in RW
     True

It is also possible to name the combinations:

     >>> class Perm(IntFlag):
     ...     R = 4
     ...     W = 2
     ...     X = 1
     ...     RWX = 7
     ...
     >>> Perm.RWX
     <Perm.RWX: 7>
     >>> ~Perm.RWX
     <Perm: 0>
     >>> Perm(7)
     <Perm.RWX: 7>

     Note: Named combinations are considered aliases.  Aliases do not
     show up during iteration, but can be returned from by-value
     lookups.

Changed in version 3.11.

Another important difference between *note IntFlag: cc1. and *note Enum:
633. is that if no flags are set (the value is 0), its boolean
evaluation is *note False: b4f.:

     >>> Perm.R & Perm.X
     <Perm: 0>
     >>> bool(Perm.R & Perm.X)
     False

Because *note IntFlag: cc1. members are also subclasses of *note int:
257. they can be combined with them (but may lose ‘IntFlag’ membership:

     >>> Perm.X | 4
     <Perm.R|X: 5>

     >>> Perm.X + 8
     9

     Note: The negation operator, ‘~’, always returns an *note IntFlag:
     cc1. member with a positive value:

          >>> (~Perm.X).value == (Perm.R|Perm.W).value == 6
          True

*note IntFlag: cc1. members can also be iterated over:

     >>> list(RW)
     [<Perm.R: 4>, <Perm.W: 2>]

Added in version 3.11.


File: python.info,  Node: Flag,  Next: Others<2>,  Prev: IntFlag,  Up: Derived Enumerations

9.6.12.4 Flag
.............

The last variation is *note Flag: 626.  Like *note IntFlag: cc1, ‘Flag’
members can be combined using the bitwise operators (&, |, ^, ~).
Unlike ‘IntFlag’, they cannot be combined with, nor compared against,
any other ‘Flag’ enumeration, nor *note int: 257.  While it is possible
to specify the values directly it is recommended to use *note auto: cc2.
as the value and let ‘Flag’ select an appropriate value.

Added in version 3.6.

Like *note IntFlag: cc1, if a combination of *note Flag: 626. members
results in no flags being set, the boolean evaluation is *note False:
b4f.:

     >>> from enum import Flag, auto
     >>> class Color(Flag):
     ...     RED = auto()
     ...     BLUE = auto()
     ...     GREEN = auto()
     ...
     >>> Color.RED & Color.GREEN
     <Color: 0>
     >>> bool(Color.RED & Color.GREEN)
     False

Individual flags should have values that are powers of two (1, 2, 4, 8,
…), while combinations of flags will not:

     >>> class Color(Flag):
     ...     RED = auto()
     ...     BLUE = auto()
     ...     GREEN = auto()
     ...     WHITE = RED | BLUE | GREEN
     ...
     >>> Color.WHITE
     <Color.WHITE: 7>

Giving a name to the “no flags set” condition does not change its
boolean value:

     >>> class Color(Flag):
     ...     BLACK = 0
     ...     RED = auto()
     ...     BLUE = auto()
     ...     GREEN = auto()
     ...
     >>> Color.BLACK
     <Color.BLACK: 0>
     >>> bool(Color.BLACK)
     False

*note Flag: 626. members can also be iterated over:

     >>> purple = Color.RED | Color.BLUE
     >>> list(purple)
     [<Color.RED: 1>, <Color.BLUE: 2>]

Added in version 3.11.

     Note: For the majority of new code, *note Enum: 633. and *note
     Flag: 626. are strongly recommended, since *note IntEnum: d06. and
     *note IntFlag: cc1. break some semantic promises of an enumeration
     (by being comparable to integers, and thus by transitivity to other
     unrelated enumerations).  ‘IntEnum’ and ‘IntFlag’ should be used
     only in cases where ‘Enum’ and ‘Flag’ will not do; for example,
     when integer constants are replaced with enumerations, or for
     interoperability with other systems.


File: python.info,  Node: Others<2>,  Prev: Flag,  Up: Derived Enumerations

9.6.12.5 Others
...............

While *note IntEnum: d06. is part of the *note enum: 56. module, it
would be very simple to implement independently:

     class IntEnum(int, ReprEnum):   # or Enum instead of ReprEnum
         pass

This demonstrates how similar derived enumerations can be defined; for
example a ‘FloatEnum’ that mixes in *note float: 2f7. instead of *note
int: 257.

Some rules:

  1. When subclassing *note Enum: 633, mix-in types must appear before
     the ‘Enum’ class itself in the sequence of bases, as in the *note
     IntEnum: d06. example above.

  2. Mix-in types must be subclassable.  For example, *note bool: 46b.
     and *note range: 94d. are not subclassable and will throw an error
     during Enum creation if used as the mix-in type.

  3. While *note Enum: 633. can have members of any type, once you mix
     in an additional type, all the members must have values of that
     type, e.g.  *note int: 257. above.  This restriction does not apply
     to mix-ins which only add methods and don’t specify another type.

  4. When another data type is mixed in, the *note value: 2786.
     attribute is 'not the same' as the enum member itself, although it
     is equivalent and will compare equal.

  5. A ‘data type’ is a mixin that defines *note __new__(): 583, or a
     *note dataclass: 1cb.

  6. %-style formatting: ‘%s’ and ‘%r’ call the *note Enum: 633. class’s
     *note __str__(): 620. and *note __repr__(): 61f. respectively;
     other codes (such as ‘%i’ or ‘%h’ for IntEnum) treat the enum
     member as its mixed-in type.

  7. *note Formatted string literals: 9b4, *note str.format(): 624, and
     *note format(): 622. will use the enum’s *note __str__(): 620.
     method.

     Note: Because *note IntEnum: d06, *note IntFlag: cc1, and *note
     StrEnum: 61d. are designed to be drop-in replacements for existing
     constants, their *note __str__(): 620. method has been reset to
     their data types’ ‘__str__()’ method.


File: python.info,  Node: When to use __new__ vs __init__,  Next: Finer Points,  Prev: Derived Enumerations,  Up: Enum HOWTO

9.6.13 When to use ‘__new__()’ vs. ‘__init__()’
-----------------------------------------------

*note __new__(): 583. must be used whenever you want to customize the
actual value of the *note Enum: 633. member.  Any other modifications
may go in either ‘__new__()’ or *note __init__(): 6b3, with ‘__init__()’
being preferred.

For example, if you want to pass several items to the constructor, but
only want one of them to be the value:

     >>> class Coordinate(bytes, Enum):
     ...     """
     ...     Coordinate with binary codes that can be indexed by the int code.
     ...     """
     ...     def __new__(cls, value, label, unit):
     ...         obj = bytes.__new__(cls, [value])
     ...         obj._value_ = value
     ...         obj.label = label
     ...         obj.unit = unit
     ...         return obj
     ...     PX = (0, 'P.X', 'km')
     ...     PY = (1, 'P.Y', 'km')
     ...     VX = (2, 'V.X', 'km/s')
     ...     VY = (3, 'V.Y', 'km/s')
     ...

     >>> print(Coordinate['PY'])
     Coordinate.PY

     >>> print(Coordinate(3))
     Coordinate.VY

     Warning: 'Do not' call ‘super().__new__()’, as the lookup-only
     ‘__new__’ is the one that is found; instead, use the data type
     directly.


File: python.info,  Node: Finer Points,  Next: How are Enums and Flags different?,  Prev: When to use __new__ vs __init__,  Up: Enum HOWTO

9.6.14 Finer Points
-------------------

* Menu:

* Supported __dunder__ and _sunder_ names::
* _Private__names::
* Enum member type::
* Creating members that are mixed with other data types::
* Boolean value of Enum classes and members::
* Enum classes with methods::
* Combining members of Flag::
* Flag and IntFlag minutia::


File: python.info,  Node: Supported __dunder__ and _sunder_ names,  Next: _Private__names,  Up: Finer Points

9.6.14.1 Supported ‘__dunder__’ and ‘_sunder_’ names
....................................................

The supported ‘__dunder__’ and ‘_sunder_’ names can be found in the
*note Enum API documentation: 27a1.


File: python.info,  Node: _Private__names,  Next: Enum member type,  Prev: Supported __dunder__ and _sunder_ names,  Up: Finer Points

9.6.14.2 _Private__names
........................

*note Private names: 1e5b. are not converted to enum members, but remain
normal attributes.

Changed in version 3.11.


File: python.info,  Node: Enum member type,  Next: Creating members that are mixed with other data types,  Prev: _Private__names,  Up: Finer Points

9.6.14.3 ‘Enum’ member type
...........................

Enum members are instances of their enum class, and are normally
accessed as ‘EnumClass.member’.  In certain situations, such as writing
custom enum behavior, being able to access one member directly from
another is useful, and is supported; however, in order to avoid name
clashes between member names and attributes/methods from mixed-in
classes, upper-case names are strongly recommended.

Changed in version 3.5.


File: python.info,  Node: Creating members that are mixed with other data types,  Next: Boolean value of Enum classes and members,  Prev: Enum member type,  Up: Finer Points

9.6.14.4 Creating members that are mixed with other data types
..............................................................

When subclassing other data types, such as *note int: 257. or *note str:
44f, with an *note Enum: 633, all values after the ‘=’ are passed to
that data type’s constructor.  For example:

     >>> class MyEnum(IntEnum):      # help(int) -> int(x, base=10) -> integer
     ...     example = '11', 16      # so x='11' and base=16
     ...
     >>> MyEnum.example.value        # and hex(11) is...
     17


File: python.info,  Node: Boolean value of Enum classes and members,  Next: Enum classes with methods,  Prev: Creating members that are mixed with other data types,  Up: Finer Points

9.6.14.5 Boolean value of ‘Enum’ classes and members
....................................................

Enum classes that are mixed with non-*note Enum: 633. types (such as
*note int: 257, *note str: 44f, etc.)  are evaluated according to the
mixed-in type’s rules; otherwise, all members evaluate as *note True:
c2d.  To make your own enum’s boolean evaluation depend on the member’s
value add the following to your class:

     def __bool__(self):
         return bool(self.value)

Plain *note Enum: 633. classes always evaluate as *note True: c2d.


File: python.info,  Node: Enum classes with methods,  Next: Combining members of Flag,  Prev: Boolean value of Enum classes and members,  Up: Finer Points

9.6.14.6 ‘Enum’ classes with methods
....................................

If you give your enum subclass extra methods, like the *note Planet:
537a. class below, those methods will show up in a *note dir(): 635. of
the member, but not of the class:

     >>> dir(Planet)
     ['EARTH', 'JUPITER', 'MARS', 'MERCURY', 'NEPTUNE', 'SATURN', 'URANUS', 'VENUS', '__class__', '__doc__', '__members__', '__module__']
     >>> dir(Planet.EARTH)
     ['__class__', '__doc__', '__module__', 'mass', 'name', 'radius', 'surface_gravity', 'value']


File: python.info,  Node: Combining members of Flag,  Next: Flag and IntFlag minutia,  Prev: Enum classes with methods,  Up: Finer Points

9.6.14.7 Combining members of ‘Flag’
....................................

Iterating over a combination of *note Flag: 626. members will only
return the members that are comprised of a single bit:

     >>> class Color(Flag):
     ...     RED = auto()
     ...     GREEN = auto()
     ...     BLUE = auto()
     ...     MAGENTA = RED | BLUE
     ...     YELLOW = RED | GREEN
     ...     CYAN = GREEN | BLUE
     ...
     >>> Color(3)  # named combination
     <Color.YELLOW: 3>
     >>> Color(7)      # not named combination
     <Color.RED|GREEN|BLUE: 7>


File: python.info,  Node: Flag and IntFlag minutia,  Prev: Combining members of Flag,  Up: Finer Points

9.6.14.8 ‘Flag’ and ‘IntFlag’ minutia
.....................................

Using the following snippet for our examples:

     >>> class Color(IntFlag):
     ...     BLACK = 0
     ...     RED = 1
     ...     GREEN = 2
     ...     BLUE = 4
     ...     PURPLE = RED | BLUE
     ...     WHITE = RED | GREEN | BLUE
     ...

the following are true:

   - single-bit flags are canonical

   - multi-bit and zero-bit flags are aliases

   - only canonical flags are returned during iteration:

          >>> list(Color.WHITE)
          [<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 4>]

   - negating a flag or flag set returns a new flag/flag set with the
     corresponding positive integer value:

          >>> Color.BLUE
          <Color.BLUE: 4>

          >>> ~Color.BLUE
          <Color.RED|GREEN: 3>

   - names of pseudo-flags are constructed from their members’ names:

          >>> (Color.RED | Color.GREEN).name
          'RED|GREEN'

          >>> class Perm(IntFlag):
          ...     R = 4
          ...     W = 2
          ...     X = 1
          ...
          >>> (Perm.R & Perm.W).name is None  # effectively Perm(0)
          True

   - multi-bit flags, aka aliases, can be returned from operations:

          >>> Color.RED | Color.BLUE
          <Color.PURPLE: 5>

          >>> Color(7)  # or Color(-1)
          <Color.WHITE: 7>

          >>> Color(0)
          <Color.BLACK: 0>

   - membership / containment checking: zero-valued flags are always
     considered to be contained:

          >>> Color.BLACK in Color.WHITE
          True

     otherwise, only if all bits of one flag are in the other flag will
     True be returned:

          >>> Color.PURPLE in Color.WHITE
          True

          >>> Color.GREEN in Color.PURPLE
          False

There is a new boundary mechanism that controls how out-of-range /
invalid bits are handled: ‘STRICT’, ‘CONFORM’, ‘EJECT’, and ‘KEEP’:

   * STRICT –> raises an exception when presented with invalid values

   * CONFORM –> discards any invalid bits

   * EJECT –> lose Flag status and become a normal int with the given
     value

   * KEEP –> keep the extra bits

        - keeps Flag status and extra bits

        - extra bits do not show up in iteration

        - extra bits do show up in repr() and str()

The default for Flag is ‘STRICT’, the default for ‘IntFlag’ is ‘EJECT’,
and the default for ‘_convert_’ is ‘KEEP’ (see ‘ssl.Options’ for an
example of when ‘KEEP’ is needed).


File: python.info,  Node: How are Enums and Flags different?,  Next: Enum Cookbook,  Prev: Finer Points,  Up: Enum HOWTO

9.6.15 How are Enums and Flags different?
-----------------------------------------

Enums have a custom metaclass that affects many aspects of both derived
*note Enum: 633. classes and their instances (members).

* Menu:

* Enum Classes::
* Flag Classes::
* Enum Members (aka instances): Enum Members aka instances.
* Flag Members::


File: python.info,  Node: Enum Classes,  Next: Flag Classes,  Up: How are Enums and Flags different?

9.6.15.1 Enum Classes
.....................

The *note EnumType: 1e5. metaclass is responsible for providing the
*note __contains__(): 1406, *note __dir__(): 15b7, *note __iter__():
c90. and other methods that allow one to do things with an *note Enum:
633. class that fail on a typical class, such as ‘list(Color)’ or
‘some_enum_var in Color’.  ‘EnumType’ is responsible for ensuring that
various other methods on the final ‘Enum’ class are correct (such as
*note __new__(): 583, *note __getnewargs__(): e04, *note __str__(): 620.
and *note __repr__(): 61f.).


File: python.info,  Node: Flag Classes,  Next: Enum Members aka instances,  Prev: Enum Classes,  Up: How are Enums and Flags different?

9.6.15.2 Flag Classes
.....................

Flags have an expanded view of aliasing: to be canonical, the value of a
flag needs to be a power-of-two value, and not a duplicate name.  So, in
addition to the *note Enum: 633. definition of alias, a flag with no
value (a.k.a.  ‘0’) or with more than one power-of-two value (e.g.  ‘3’)
is considered an alias.


File: python.info,  Node: Enum Members aka instances,  Next: Flag Members,  Prev: Flag Classes,  Up: How are Enums and Flags different?

9.6.15.3 Enum Members (aka instances)
.....................................

The most interesting thing about enum members is that they are
singletons.  *note EnumType: 1e5. creates them all while it is creating
the enum class itself, and then puts a custom *note __new__(): 583. in
place to ensure that no new ones are ever instantiated by returning only
the existing member instances.


File: python.info,  Node: Flag Members,  Prev: Enum Members aka instances,  Up: How are Enums and Flags different?

9.6.15.4 Flag Members
.....................

Flag members can be iterated over just like the *note Flag: 626. class,
and only the canonical members will be returned.  For example:

     >>> list(Color)
     [<Color.RED: 1>, <Color.GREEN: 2>, <Color.BLUE: 4>]

(Note that ‘BLACK’, ‘PURPLE’, and ‘WHITE’ do not show up.)

Inverting a flag member returns the corresponding positive value, rather
than a negative value — for example:

     >>> ~Color.RED
     <Color.GREEN|BLUE: 6>

Flag members have a length corresponding to the number of power-of-two
values they contain.  For example:

     >>> len(Color.PURPLE)
     2


File: python.info,  Node: Enum Cookbook,  Next: Subclassing EnumType,  Prev: How are Enums and Flags different?,  Up: Enum HOWTO

9.6.16 Enum Cookbook
--------------------

While *note Enum: 633, *note IntEnum: d06, *note StrEnum: 61d, *note
Flag: 626, and *note IntFlag: cc1. are expected to cover the majority of
use-cases, they cannot cover them all.  Here are recipes for some
different types of enumerations that can be used directly, or as
examples for creating one’s own.

* Menu:

* Omitting values::
* OrderedEnum::
* DuplicateFreeEnum::
* MultiValueEnum::
* Planet::
* TimePeriod::


File: python.info,  Node: Omitting values,  Next: OrderedEnum,  Up: Enum Cookbook

9.6.16.1 Omitting values
........................

In many use-cases, one doesn’t care what the actual value of an
enumeration is.  There are several ways to define this type of simple
enumeration:

   - use instances of *note auto: cc2. for the value

   - use instances of *note object: a9b. as the value

   - use a descriptive string as the value

   - use a tuple as the value and a custom *note __new__(): 583. to
     replace the tuple with an *note int: 257. value

Using any of these methods signifies to the user that these values are
not important, and also enables one to add, remove, or reorder members
without having to renumber the remaining members.

* Menu:

* Using auto::
* Using object::
* Using a descriptive string::
* Using a custom __new__(): Using a custom __new__.


File: python.info,  Node: Using auto,  Next: Using object,  Up: Omitting values

9.6.16.2 Using ‘auto’
.....................

Using *note auto: cc2. would look like:

     >>> class Color(Enum):
     ...     RED = auto()
     ...     BLUE = auto()
     ...     GREEN = auto()
     ...
     >>> Color.GREEN
     <Color.GREEN: 3>


File: python.info,  Node: Using object,  Next: Using a descriptive string,  Prev: Using auto,  Up: Omitting values

9.6.16.3 Using ‘object’
.......................

Using *note object: a9b. would look like:

     >>> class Color(Enum):
     ...     RED = object()
     ...     GREEN = object()
     ...     BLUE = object()
     ...
     >>> Color.GREEN
     <Color.GREEN: <object object at 0x...>>

This is also a good example of why you might want to write your own
*note __repr__(): 61f.:

     >>> class Color(Enum):
     ...     RED = object()
     ...     GREEN = object()
     ...     BLUE = object()
     ...     def __repr__(self):
     ...         return "<%s.%s>" % (self.__class__.__name__, self._name_)
     ...
     >>> Color.GREEN
     <Color.GREEN>


File: python.info,  Node: Using a descriptive string,  Next: Using a custom __new__,  Prev: Using object,  Up: Omitting values

9.6.16.4 Using a descriptive string
...................................

Using a string as the value would look like:

     >>> class Color(Enum):
     ...     RED = 'stop'
     ...     GREEN = 'go'
     ...     BLUE = 'too fast!'
     ...
     >>> Color.GREEN
     <Color.GREEN: 'go'>


File: python.info,  Node: Using a custom __new__,  Prev: Using a descriptive string,  Up: Omitting values

9.6.16.5 Using a custom ‘__new__()’
...................................

Using an auto-numbering *note __new__(): 583. would look like:

     >>> class AutoNumber(Enum):
     ...     def __new__(cls):
     ...         value = len(cls.__members__) + 1
     ...         obj = object.__new__(cls)
     ...         obj._value_ = value
     ...         return obj
     ...
     >>> class Color(AutoNumber):
     ...     RED = ()
     ...     GREEN = ()
     ...     BLUE = ()
     ...
     >>> Color.GREEN
     <Color.GREEN: 2>

To make a more general purpose ‘AutoNumber’, add ‘*args’ to the
signature:

     >>> class AutoNumber(Enum):
     ...     def __new__(cls, *args):      # this is the only change from above
     ...         value = len(cls.__members__) + 1
     ...         obj = object.__new__(cls)
     ...         obj._value_ = value
     ...         return obj
     ...

Then when you inherit from ‘AutoNumber’ you can write your own
‘__init__’ to handle any extra arguments:

     >>> class Swatch(AutoNumber):
     ...     def __init__(self, pantone='unknown'):
     ...         self.pantone = pantone
     ...     AUBURN = '3497'
     ...     SEA_GREEN = '1246'
     ...     BLEACHED_CORAL = () # New color, no Pantone code yet!
     ...
     >>> Swatch.SEA_GREEN
     <Swatch.SEA_GREEN: 2>
     >>> Swatch.SEA_GREEN.pantone
     '1246'
     >>> Swatch.BLEACHED_CORAL.pantone
     'unknown'

     Note: The *note __new__(): 583. method, if defined, is used during
     creation of the Enum members; it is then replaced by Enum’s
     ‘__new__()’ which is used after class creation for lookup of
     existing members.

     Warning: 'Do not' call ‘super().__new__()’, as the lookup-only
     ‘__new__’ is the one that is found; instead, use the data type
     directly – e.g.:

          obj = int.__new__(cls, value)


File: python.info,  Node: OrderedEnum,  Next: DuplicateFreeEnum,  Prev: Omitting values,  Up: Enum Cookbook

9.6.16.6 OrderedEnum
....................

An ordered enumeration that is not based on *note IntEnum: d06. and so
maintains the normal *note Enum: 633. invariants (such as not being
comparable to other enumerations):

     >>> class OrderedEnum(Enum):
     ...     def __ge__(self, other):
     ...         if self.__class__ is other.__class__:
     ...             return self.value >= other.value
     ...         return NotImplemented
     ...     def __gt__(self, other):
     ...         if self.__class__ is other.__class__:
     ...             return self.value > other.value
     ...         return NotImplemented
     ...     def __le__(self, other):
     ...         if self.__class__ is other.__class__:
     ...             return self.value <= other.value
     ...         return NotImplemented
     ...     def __lt__(self, other):
     ...         if self.__class__ is other.__class__:
     ...             return self.value < other.value
     ...         return NotImplemented
     ...
     >>> class Grade(OrderedEnum):
     ...     A = 5
     ...     B = 4
     ...     C = 3
     ...     D = 2
     ...     F = 1
     ...
     >>> Grade.C < Grade.A
     True


File: python.info,  Node: DuplicateFreeEnum,  Next: MultiValueEnum,  Prev: OrderedEnum,  Up: Enum Cookbook

9.6.16.7 DuplicateFreeEnum
..........................

Raises an error if a duplicate member value is found instead of creating
an alias:

     >>> class DuplicateFreeEnum(Enum):
     ...     def __init__(self, *args):
     ...         cls = self.__class__
     ...         if any(self.value == e.value for e in cls):
     ...             a = self.name
     ...             e = cls(self.value).name
     ...             raise ValueError(
     ...                 "aliases not allowed in DuplicateFreeEnum:  %r --> %r"
     ...                 % (a, e))
     ...
     >>> class Color(DuplicateFreeEnum):
     ...     RED = 1
     ...     GREEN = 2
     ...     BLUE = 3
     ...     GRENE = 2
     ...
     Traceback (most recent call last):
       ...
     ValueError: aliases not allowed in DuplicateFreeEnum:  'GRENE' --> 'GREEN'

     Note: This is a useful example for subclassing Enum to add or
     change other behaviors as well as disallowing aliases.  If the only
     desired change is disallowing aliases, the *note unique(): 2779.
     decorator can be used instead.


File: python.info,  Node: MultiValueEnum,  Next: Planet,  Prev: DuplicateFreeEnum,  Up: Enum Cookbook

9.6.16.8 MultiValueEnum
.......................

Supports having more than one value per member:

     >>> class MultiValueEnum(Enum):
     ...     def __new__(cls, value, *values):
     ...         self = object.__new__(cls)
     ...         self._value_ = value
     ...         for v in values:
     ...             self._add_value_alias_(v)
     ...         return self
     ...
     >>> class DType(MultiValueEnum):
     ...     float32 = 'f', 8
     ...     double64 = 'd', 9
     ...
     >>> DType('f')
     <DType.float32: 'f'>
     >>> DType(9)
     <DType.double64: 'd'>


File: python.info,  Node: Planet,  Next: TimePeriod,  Prev: MultiValueEnum,  Up: Enum Cookbook

9.6.16.9 Planet
...............

If *note __new__(): 583. or *note __init__(): 6b3. is defined, the value
of the enum member will be passed to those methods:

     >>> class Planet(Enum):
     ...     MERCURY = (3.303e+23, 2.4397e6)
     ...     VENUS   = (4.869e+24, 6.0518e6)
     ...     EARTH   = (5.976e+24, 6.37814e6)
     ...     MARS    = (6.421e+23, 3.3972e6)
     ...     JUPITER = (1.9e+27,   7.1492e7)
     ...     SATURN  = (5.688e+26, 6.0268e7)
     ...     URANUS  = (8.686e+25, 2.5559e7)
     ...     NEPTUNE = (1.024e+26, 2.4746e7)
     ...     def __init__(self, mass, radius):
     ...         self.mass = mass       # in kilograms
     ...         self.radius = radius   # in meters
     ...     @property
     ...     def surface_gravity(self):
     ...         # universal gravitational constant  (m3 kg-1 s-2)
     ...         G = 6.67300E-11
     ...         return G * self.mass / (self.radius * self.radius)
     ...
     >>> Planet.EARTH.value
     (5.976e+24, 6378140.0)
     >>> Planet.EARTH.surface_gravity
     9.802652743337129


File: python.info,  Node: TimePeriod,  Prev: Planet,  Up: Enum Cookbook

9.6.16.10 TimePeriod
....................

An example to show the *note _ignore_: 278b. attribute in use:

     >>> import datetime as dt
     >>> class Period(dt.timedelta, Enum):
     ...     "different lengths of time"
     ...     _ignore_ = 'Period i'
     ...     Period = vars()
     ...     for i in range(367):
     ...         Period['day_%d' % i] = i
     ...
     >>> list(Period)[:2]
     [<Period.day_0: datetime.timedelta(0)>, <Period.day_1: datetime.timedelta(days=1)>]
     >>> list(Period)[-2:]
     [<Period.day_365: datetime.timedelta(days=365)>, <Period.day_366: datetime.timedelta(days=366)>]


File: python.info,  Node: Subclassing EnumType,  Prev: Enum Cookbook,  Up: Enum HOWTO

9.6.17 Subclassing EnumType
---------------------------

While most enum needs can be met by customizing *note Enum: 633.
subclasses, either with class decorators or custom functions, *note
EnumType: 1e5. can be subclassed to provide a different Enum experience.


File: python.info,  Node: Functional Programming HOWTO,  Next: Logging HOWTO,  Prev: Enum HOWTO,  Up: Python HOWTOs

9.7 Functional Programming HOWTO
================================


Author: A. M. Kuchling


Release: 0.32

In this document, we’ll take a tour of Python’s features suitable for
implementing programs in a functional style.  After an introduction to
the concepts of functional programming, we’ll look at language features
such as *note iterator: 1ac.s and *note generator: 109f.s and relevant
library modules such as *note itertools: 81. and *note functools: 5f.

* Menu:

* Introduction: Introduction<14>.
* Iterators: Iterators<2>.
* Generator expressions and list comprehensions::
* Generators: Generators<2>.
* Built-in functions: Built-in functions<2>.
* The itertools module::
* The functools module::
* Small functions and the lambda expression::
* Revision History and Acknowledgements::
* References: References<2>.


File: python.info,  Node: Introduction<14>,  Next: Iterators<2>,  Up: Functional Programming HOWTO

9.7.1 Introduction
------------------

This section explains the basic concept of functional programming; if
you’re just interested in learning about Python language features, skip
to the next section on *note Iterators: 53a3.

Programming languages support decomposing problems in several different
ways:

   * Most programming languages are 'procedural': programs are lists of
     instructions that tell the computer what to do with the program’s
     input.  C, Pascal, and even Unix shells are procedural languages.

   * In 'declarative' languages, you write a specification that
     describes the problem to be solved, and the language implementation
     figures out how to perform the computation efficiently.  SQL is the
     declarative language you’re most likely to be familiar with; a SQL
     query describes the data set you want to retrieve, and the SQL
     engine decides whether to scan tables or use indexes, which
     subclauses should be performed first, etc.

   * 'Object-oriented' programs manipulate collections of objects.
     Objects have internal state and support methods that query or
     modify this internal state in some way.  Smalltalk and Java are
     object-oriented languages.  C++ and Python are languages that
     support object-oriented programming, but don’t force the use of
     object-oriented features.

   * 'Functional' programming decomposes a problem into a set of
     functions.  Ideally, functions only take inputs and produce
     outputs, and don’t have any internal state that affects the output
     produced for a given input.  Well-known functional languages
     include the ML family (Standard ML, OCaml, and other variants) and
     Haskell.

The designers of some computer languages choose to emphasize one
particular approach to programming.  This often makes it difficult to
write programs that use a different approach.  Other languages are
multi-paradigm languages that support several different approaches.
Lisp, C++, and Python are multi-paradigm; you can write programs or
libraries that are largely procedural, object-oriented, or functional in
all of these languages.  In a large program, different sections might be
written using different approaches; the GUI might be object-oriented
while the processing logic is procedural or functional, for example.

In a functional program, input flows through a set of functions.  Each
function operates on its input and produces some output.  Functional
style discourages functions with side effects that modify internal state
or make other changes that aren’t visible in the function’s return
value.  Functions that have no side effects at all are called 'purely
functional'.  Avoiding side effects means not using data structures that
get updated as a program runs; every function’s output must only depend
on its input.

Some languages are very strict about purity and don’t even have
assignment statements such as ‘a=3’ or ‘c = a + b’, but it’s difficult
to avoid all side effects, such as printing to the screen or writing to
a disk file.  Another example is a call to the *note print(): fae. or
*note time.sleep(): 6a0. function, neither of which returns a useful
value.  Both are called only for their side effects of sending some text
to the screen or pausing execution for a second.

Python programs written in functional style usually won’t go to the
extreme of avoiding all I/O or all assignments; instead, they’ll provide
a functional-appearing interface but will use non-functional features
internally.  For example, the implementation of a function will still
use assignments to local variables, but won’t modify global variables or
have other side effects.

Functional programming can be considered the opposite of object-oriented
programming.  Objects are little capsules containing some internal state
along with a collection of method calls that let you modify this state,
and programs consist of making the right set of state changes.
Functional programming wants to avoid state changes as much as possible
and works with data flowing between functions.  In Python you might
combine the two approaches by writing functions that take and return
instances representing objects in your application (e-mail messages,
transactions, etc.).

Functional design may seem like an odd constraint to work under.  Why
should you avoid objects and side effects?  There are theoretical and
practical advantages to the functional style:

   * Formal provability.

   * Modularity.

   * Composability.

   * Ease of debugging and testing.

* Menu:

* Formal provability::
* Modularity::
* Ease of debugging and testing::
* Composability::


File: python.info,  Node: Formal provability,  Next: Modularity,  Up: Introduction<14>

9.7.1.1 Formal provability
..........................

A theoretical benefit is that it’s easier to construct a mathematical
proof that a functional program is correct.

For a long time researchers have been interested in finding ways to
mathematically prove programs correct.  This is different from testing a
program on numerous inputs and concluding that its output is usually
correct, or reading a program’s source code and concluding that the code
looks right; the goal is instead a rigorous proof that a program
produces the right result for all possible inputs.

The technique used to prove programs correct is to write down
'invariants', properties of the input data and of the program’s
variables that are always true.  For each line of code, you then show
that if invariants X and Y are true 'before' the line is executed, the
slightly different invariants X’ and Y’ are true 'after' the line is
executed.  This continues until you reach the end of the program, at
which point the invariants should match the desired conditions on the
program’s output.

Functional programming’s avoidance of assignments arose because
assignments are difficult to handle with this technique; assignments can
break invariants that were true before the assignment without producing
any new invariants that can be propagated onward.

Unfortunately, proving programs correct is largely impractical and not
relevant to Python software.  Even trivial programs require proofs that
are several pages long; the proof of correctness for a moderately
complicated program would be enormous, and few or none of the programs
you use daily (the Python interpreter, your XML parser, your web
browser) could be proven correct.  Even if you wrote down or generated a
proof, there would then be the question of verifying the proof; maybe
there’s an error in it, and you wrongly believe you’ve proved the
program correct.


File: python.info,  Node: Modularity,  Next: Ease of debugging and testing,  Prev: Formal provability,  Up: Introduction<14>

9.7.1.2 Modularity
..................

A more practical benefit of functional programming is that it forces you
to break apart your problem into small pieces.  Programs are more
modular as a result.  It’s easier to specify and write a small function
that does one thing than a large function that performs a complicated
transformation.  Small functions are also easier to read and to check
for errors.


File: python.info,  Node: Ease of debugging and testing,  Next: Composability,  Prev: Modularity,  Up: Introduction<14>

9.7.1.3 Ease of debugging and testing
.....................................

Testing and debugging a functional-style program is easier.

Debugging is simplified because functions are generally small and
clearly specified.  When a program doesn’t work, each function is an
interface point where you can check that the data are correct.  You can
look at the intermediate inputs and outputs to quickly isolate the
function that’s responsible for a bug.

Testing is easier because each function is a potential subject for a
unit test.  Functions don’t depend on system state that needs to be
replicated before running a test; instead you only have to synthesize
the right input and then check that the output matches expectations.


File: python.info,  Node: Composability,  Prev: Ease of debugging and testing,  Up: Introduction<14>

9.7.1.4 Composability
.....................

As you work on a functional-style program, you’ll write a number of
functions with varying inputs and outputs.  Some of these functions will
be unavoidably specialized to a particular application, but others will
be useful in a wide variety of programs.  For example, a function that
takes a directory path and returns all the XML files in the directory,
or a function that takes a filename and returns its contents, can be
applied to many different situations.

Over time you’ll form a personal library of utilities.  Often you’ll
assemble new programs by arranging existing functions in a new
configuration and writing a few functions specialized for the current
task.


File: python.info,  Node: Iterators<2>,  Next: Generator expressions and list comprehensions,  Prev: Introduction<14>,  Up: Functional Programming HOWTO

9.7.2 Iterators
---------------

I’ll start by looking at a Python language feature that’s an important
foundation for writing functional-style programs: iterators.

An iterator is an object representing a stream of data; this object
returns the data one element at a time.  A Python iterator must support
a method called *note __next__(): 1315. that takes no arguments and
always returns the next element of the stream.  If there are no more
elements in the stream, ‘__next__()’ must raise the *note StopIteration:
c1b. exception.  Iterators don’t have to be finite, though; it’s
perfectly reasonable to write an iterator that produces an infinite
stream of data.

The built-in *note iter(): 7db. function takes an arbitrary object and
tries to return an iterator that will return the object’s contents or
elements, raising *note TypeError: 2c3. if the object doesn’t support
iteration.  Several of Python’s built-in data types support iteration,
the most common being lists and dictionaries.  An object is called *note
iterable: 126d. if you can get an iterator for it.

You can experiment with the iteration interface manually:

     >>> L = [1, 2, 3]
     >>> it = iter(L)
     >>> it
     <...iterator object at ...>
     >>> it.__next__()  # same as next(it)
     1
     >>> next(it)
     2
     >>> next(it)
     3
     >>> next(it)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     StopIteration
     >>>

Python expects iterable objects in several different contexts, the most
important being the *note for: 2f2. statement.  In the statement ‘for X
in Y’, Y must be an iterator or some object for which *note iter(): 7db.
can create an iterator.  These two statements are equivalent:

     for i in iter(obj):
         print(i)

     for i in obj:
         print(i)

Iterators can be materialized as lists or tuples by using the *note
list(): 614. or *note tuple(): 373. constructor functions:

     >>> L = [1, 2, 3]
     >>> iterator = iter(L)
     >>> t = tuple(iterator)
     >>> t
     (1, 2, 3)

Sequence unpacking also supports iterators: if you know an iterator will
return N elements, you can unpack them into an N-tuple:

     >>> L = [1, 2, 3]
     >>> iterator = iter(L)
     >>> a, b, c = iterator
     >>> a, b, c
     (1, 2, 3)

Built-in functions such as *note max(): f40. and *note min(): f3f. can
take a single iterator argument and will return the largest or smallest
element.  The ‘"in"’ and ‘"not in"’ operators also support iterators: ‘X
in iterator’ is true if X is found in the stream returned by the
iterator.  You’ll run into obvious problems if the iterator is infinite;
‘max()’, ‘min()’ will never return, and if the element X never appears
in the stream, the ‘"in"’ and ‘"not in"’ operators won’t return either.

Note that you can only go forward in an iterator; there’s no way to get
the previous element, reset the iterator, or make a copy of it.
Iterator objects can optionally provide these additional capabilities,
but the iterator protocol only specifies the *note __next__(): 1315.
method.  Functions may therefore consume all of the iterator’s output,
and if you need to do something different with the same stream, you’ll
have to create a new iterator.

* Menu:

* Data Types That Support Iterators::


File: python.info,  Node: Data Types That Support Iterators,  Up: Iterators<2>

9.7.2.1 Data Types That Support Iterators
.........................................

We’ve already seen how lists and tuples support iterators.  In fact, any
Python sequence type, such as strings, will automatically support
creation of an iterator.

Calling *note iter(): 7db. on a dictionary returns an iterator that will
loop over the dictionary’s keys:

     >>> m = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
     ...      'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}
     >>> for key in m:
     ...     print(key, m[key])
     Jan 1
     Feb 2
     Mar 3
     Apr 4
     May 5
     Jun 6
     Jul 7
     Aug 8
     Sep 9
     Oct 10
     Nov 11
     Dec 12

Note that starting with Python 3.7, dictionary iteration order is
guaranteed to be the same as the insertion order.  In earlier versions,
the behaviour was unspecified and could vary between implementations.

Applying *note iter(): 7db. to a dictionary always loops over the keys,
but dictionaries have methods that return other iterators.  If you want
to iterate over values or key/value pairs, you can explicitly call the
*note values(): 7d2. or *note items(): 7d3. methods to get an
appropriate iterator.

The *note dict(): 256. constructor can accept an iterator that returns a
finite stream of ‘(key, value)’ tuples:

     >>> L = [('Italy', 'Rome'), ('France', 'Paris'), ('US', 'Washington DC')]
     >>> dict(iter(L))
     {'Italy': 'Rome', 'France': 'Paris', 'US': 'Washington DC'}

Files also support iteration by calling the *note readline(): 1e5e.
method until there are no more lines in the file.  This means you can
read each line of a file like this:

     for line in file:
         # do something for each line
         ...

Sets can take their contents from an iterable and let you iterate over
the set’s elements:

     >>> S = {2, 3, 5, 7, 11, 13}
     >>> for i in S:
     ...     print(i)
     2
     3
     5
     7
     11
     13


File: python.info,  Node: Generator expressions and list comprehensions,  Next: Generators<2>,  Prev: Iterators<2>,  Up: Functional Programming HOWTO

9.7.3 Generator expressions and list comprehensions
---------------------------------------------------

Two common operations on an iterator’s output are 1) performing some
operation for every element, 2) selecting a subset of elements that meet
some condition.  For example, given a list of strings, you might want to
strip off trailing whitespace from each line or extract all the strings
containing a given substring.

List comprehensions and generator expressions (short form: “listcomps”
and “genexps”) are a concise notation for such operations, borrowed from
the functional programming language Haskell
(‘https://www.haskell.org/’).  You can strip all the whitespace from a
stream of strings with the following code:

     >>> line_list = ['  line 1\n', 'line 2  \n', ' \n', '']

     >>> # Generator expression -- returns iterator
     >>> stripped_iter = (line.strip() for line in line_list)

     >>> # List comprehension -- returns list
     >>> stripped_list = [line.strip() for line in line_list]

You can select only certain elements by adding an ‘"if"’ condition:

     >>> stripped_list = [line.strip() for line in line_list
     ...                  if line != ""]

With a list comprehension, you get back a Python list; ‘stripped_list’
is a list containing the resulting lines, not an iterator.  Generator
expressions return an iterator that computes the values as necessary,
not needing to materialize all the values at once.  This means that list
comprehensions aren’t useful if you’re working with iterators that
return an infinite stream or a very large amount of data.  Generator
expressions are preferable in these situations.

Generator expressions are surrounded by parentheses (“()”) and list
comprehensions are surrounded by square brackets (“[]”).  Generator
expressions have the form:

     ( expression for expr in sequence1
                  if condition1
                  for expr2 in sequence2
                  if condition2
                  for expr3 in sequence3
                  ...
                  if condition3
                  for exprN in sequenceN
                  if conditionN )

Again, for a list comprehension only the outside brackets are different
(square brackets instead of parentheses).

The elements of the generated output will be the successive values of
‘expression’.  The ‘if’ clauses are all optional; if present,
‘expression’ is only evaluated and added to the result when ‘condition’
is true.

Generator expressions always have to be written inside parentheses, but
the parentheses signalling a function call also count.  If you want to
create an iterator that will be immediately passed to a function you can
write:

     obj_total = sum(obj.count for obj in list_all_objects())

The ‘for...in’ clauses contain the sequences to be iterated over.  The
sequences do not have to be the same length, because they are iterated
over from left to right, 'not' in parallel.  For each element in
‘sequence1’, ‘sequence2’ is looped over from the beginning.  ‘sequence3’
is then looped over for each resulting pair of elements from ‘sequence1’
and ‘sequence2’.

To put it another way, a list comprehension or generator expression is
equivalent to the following Python code:

     for expr1 in sequence1:
         if not (condition1):
             continue   # Skip this element
         for expr2 in sequence2:
             if not (condition2):
                 continue   # Skip this element
             ...
             for exprN in sequenceN:
                 if not (conditionN):
                     continue   # Skip this element

                 # Output the value of
                 # the expression.

This means that when there are multiple ‘for...in’ clauses but no ‘if’
clauses, the length of the resulting output will be equal to the product
of the lengths of all the sequences.  If you have two lists of length 3,
the output list is 9 elements long:

     >>> seq1 = 'abc'
     >>> seq2 = (1, 2, 3)
     >>> [(x, y) for x in seq1 for y in seq2]
     [('a', 1), ('a', 2), ('a', 3),
      ('b', 1), ('b', 2), ('b', 3),
      ('c', 1), ('c', 2), ('c', 3)]

To avoid introducing an ambiguity into Python’s grammar, if ‘expression’
is creating a tuple, it must be surrounded with parentheses.  The first
list comprehension below is a syntax error, while the second one is
correct:

     # Syntax error
     [x, y for x in seq1 for y in seq2]
     # Correct
     [(x, y) for x in seq1 for y in seq2]


File: python.info,  Node: Generators<2>,  Next: Built-in functions<2>,  Prev: Generator expressions and list comprehensions,  Up: Functional Programming HOWTO

9.7.4 Generators
----------------

Generators are a special class of functions that simplify the task of
writing iterators.  Regular functions compute a value and return it, but
generators return an iterator that returns a stream of values.

You’re doubtless familiar with how regular function calls work in Python
or C. When you call a function, it gets a private namespace where its
local variables are created.  When the function reaches a ‘return’
statement, the local variables are destroyed and the value is returned
to the caller.  A later call to the same function creates a new private
namespace and a fresh set of local variables.  But, what if the local
variables weren’t thrown away on exiting a function?  What if you could
later resume the function where it left off?  This is what generators
provide; they can be thought of as resumable functions.

Here’s the simplest example of a generator function:

     >>> def generate_ints(N):
     ...    for i in range(N):
     ...        yield i

Any function containing a *note yield: 9d8. keyword is a generator
function; this is detected by Python’s *note bytecode: 187. compiler
which compiles the function specially as a result.

When you call a generator function, it doesn’t return a single value;
instead it returns a generator object that supports the iterator
protocol.  On executing the ‘yield’ expression, the generator outputs
the value of ‘i’, similar to a ‘return’ statement.  The big difference
between ‘yield’ and a ‘return’ statement is that on reaching a ‘yield’
the generator’s state of execution is suspended and local variables are
preserved.  On the next call to the generator’s *note __next__(): 1e66.
method, the function will resume executing.

Here’s a sample usage of the ‘generate_ints()’ generator:

     >>> gen = generate_ints(3)
     >>> gen
     <generator object generate_ints at ...>
     >>> next(gen)
     0
     >>> next(gen)
     1
     >>> next(gen)
     2
     >>> next(gen)
     Traceback (most recent call last):
       File "stdin", line 1, in <module>
       File "stdin", line 2, in generate_ints
     StopIteration

You could equally write ‘for i in generate_ints(5)’, or ‘a, b, c =
generate_ints(3)’.

Inside a generator function, ‘return value’ causes
‘StopIteration(value)’ to be raised from the *note __next__(): 1e66.
method.  Once this happens, or the bottom of the function is reached,
the procession of values ends and the generator cannot yield any further
values.

You could achieve the effect of generators manually by writing your own
class and storing all the local variables of the generator as instance
variables.  For example, returning a list of integers could be done by
setting ‘self.count’ to 0, and having the *note __next__(): 1315. method
increment ‘self.count’ and return it.  However, for a moderately
complicated generator, writing a corresponding class can be much
messier.

The test suite included with Python’s library,
Lib/test/test_generators.py(1), contains a number of more interesting
examples.  Here’s one generator that implements an in-order traversal of
a tree using generators recursively.

     # A recursive generator that generates Tree leaves in in-order.
     def inorder(t):
         if t:
             for x in inorder(t.left):
                 yield x

             yield t.label

             for x in inorder(t.right):
                 yield x

Two other examples in ‘test_generators.py’ produce solutions for the
N-Queens problem (placing N queens on an NxN chess board so that no
queen threatens another) and the Knight’s Tour (finding a route that
takes a knight to every square of an NxN chessboard without visiting any
square twice).

* Menu:

* Passing values into a generator::

   ---------- Footnotes ----------

   (1) 
https://github.com/python/cpython/tree/3.13/Lib/test/test_generators.py


File: python.info,  Node: Passing values into a generator,  Up: Generators<2>

9.7.4.1 Passing values into a generator
.......................................

In Python 2.4 and earlier, generators only produced output.  Once a
generator’s code was invoked to create an iterator, there was no way to
pass any new information into the function when its execution is
resumed.  You could hack together this ability by making the generator
look at a global variable or by passing in some mutable object that
callers then modify, but these approaches are messy.

In Python 2.5 there’s a simple way to pass values into a generator.
*note yield: 9d8. became an expression, returning a value that can be
assigned to a variable or otherwise operated on:

     val = (yield i)

I recommend that you 'always' put parentheses around a ‘yield’
expression when you’re doing something with the returned value, as in
the above example.  The parentheses aren’t always necessary, but it’s
easier to always add them instead of having to remember when they’re
needed.

( PEP 342(1) explains the exact rules, which are that a
‘yield’-expression must always be parenthesized except when it occurs at
the top-level expression on the right-hand side of an assignment.  This
means you can write ‘val = yield i’ but have to use parentheses when
there’s an operation, as in ‘val = (yield i) + 12’.)

Values are sent into a generator by calling its *note send(value): 217d.
method.  This method resumes the generator’s code and the ‘yield’
expression returns the specified value.  If the regular *note
__next__(): 1e66. method is called, the ‘yield’ returns ‘None’.

Here’s a simple counter that increments by 1 and allows changing the
value of the internal counter.

     def counter(maximum):
         i = 0
         while i < maximum:
             val = (yield i)
             # If value provided, change counter
             if val is not None:
                 i = val
             else:
                 i += 1

And here’s an example of changing the counter:

     >>> it = counter(10)
     >>> next(it)
     0
     >>> next(it)
     1
     >>> it.send(8)
     8
     >>> next(it)
     9
     >>> next(it)
     Traceback (most recent call last):
       File "t.py", line 15, in <module>
         it.next()
     StopIteration

Because ‘yield’ will often be returning ‘None’, you should always check
for this case.  Don’t just use its value in expressions unless you’re
sure that the *note send(): 217d. method will be the only method used to
resume your generator function.

In addition to *note send(): 217d, there are two other methods on
generators:

   * *note throw(value): 4fb. is used to raise an exception inside the
     generator; the exception is raised by the ‘yield’ expression where
     the generator’s execution is paused.

   * *note close(): 15df. sends a *note GeneratorExit: 1414. exception
     to the generator to terminate the iteration.  On receiving this
     exception, the generator’s code must either raise ‘GeneratorExit’
     or *note StopIteration: c1b.; catching the exception and doing
     anything else is illegal and will trigger a *note RuntimeError:
     195.  ‘close()’ will also be called by Python’s garbage collector
     when the generator is garbage-collected.

     If you need to run cleanup code when a *note GeneratorExit: 1414.
     occurs, I suggest using a ‘try: ... finally:’ suite instead of
     catching ‘GeneratorExit’.

The cumulative effect of these changes is to turn generators from
one-way producers of information into both producers and consumers.

Generators also become 'coroutines', a more generalized form of
subroutines.  Subroutines are entered at one point and exited at another
point (the top of the function, and a ‘return’ statement), but
coroutines can be entered, exited, and resumed at many different points
(the ‘yield’ statements).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0342/


File: python.info,  Node: Built-in functions<2>,  Next: The itertools module,  Prev: Generators<2>,  Up: Functional Programming HOWTO

9.7.5 Built-in functions
------------------------

Let’s look in more detail at built-in functions often used with
iterators.

Two of Python’s built-in functions, *note map(): 86a. and *note
filter(): 86b. duplicate the features of generator expressions:

*note map(f, iterA, iterB, ...): 86a. returns an iterator over the sequence

     ‘f(iterA[0], iterB[0]), f(iterA[1], iterB[1]), f(iterA[2],
     iterB[2]), ...’.

          >>> def upper(s):
          ...     return s.upper()

          >>> list(map(upper, ['sentence', 'fragment']))
          ['SENTENCE', 'FRAGMENT']
          >>> [upper(s) for s in ['sentence', 'fragment']]
          ['SENTENCE', 'FRAGMENT']

You can of course achieve the same effect with a list comprehension.

*note filter(predicate, iter): 86b. returns an iterator over all the
sequence elements that meet a certain condition, and is similarly
duplicated by list comprehensions.  A 'predicate' is a function that
returns the truth value of some condition; for use with ‘filter()’, the
predicate must take a single value.

     >>> def is_even(x):
     ...     return (x % 2) == 0

     >>> list(filter(is_even, range(10)))
     [0, 2, 4, 6, 8]

This can also be written as a list comprehension:

     >>> list(x for x in range(10) if is_even(x))
     [0, 2, 4, 6, 8]

*note enumerate(iter, start=0): 14d0. counts off the elements in the
iterable returning 2-tuples containing the count (from 'start') and each
element.

     >>> for item in enumerate(['subject', 'verb', 'object']):
     ...     print(item)
     (0, 'subject')
     (1, 'verb')
     (2, 'object')

*note enumerate(): 14d0. is often used when looping through a list and
recording the indexes at which certain conditions are met:

     f = open('data.txt', 'r')
     for i, line in enumerate(f):
         if line.strip() == '':
             print('Blank line at line #%i' % i)

*note sorted(iterable, key=None, reverse=False): bed. collects all the
elements of the iterable into a list, sorts the list, and returns the
sorted result.  The 'key' and 'reverse' arguments are passed through to
the constructed list’s *note sort(): bee. method.

     >>> import random
     >>> # Generate 8 random numbers between [0, 10000)
     >>> rand_list = random.sample(range(10000), 8)
     >>> rand_list
     [769, 7953, 9828, 6431, 8442, 9878, 6213, 2207]
     >>> sorted(rand_list)
     [769, 2207, 6213, 6431, 7953, 8442, 9828, 9878]
     >>> sorted(rand_list, reverse=True)
     [9878, 9828, 8442, 7953, 6431, 6213, 2207, 769]

(For a more detailed discussion of sorting, see the *note Sorting
Techniques: 2337.)

The *note any(iter): 146f. and *note all(iter): 1470. built-ins look at
the truth values of an iterable’s contents.  ‘any()’ returns ‘True’ if
any element in the iterable is a true value, and ‘all()’ returns ‘True’
if all of the elements are true values:

     >>> any([0, 1, 0])
     True
     >>> any([0, 0, 0])
     False
     >>> any([1, 1, 1])
     True
     >>> all([0, 1, 0])
     False
     >>> all([0, 0, 0])
     False
     >>> all([1, 1, 1])
     True

*note zip(iterA, iterB, ...): 7d4. takes one element from each iterable
and returns them in a tuple:

     zip(['a', 'b', 'c'], (1, 2, 3)) =>
       ('a', 1), ('b', 2), ('c', 3)

It doesn’t construct an in-memory list and exhaust all the input
iterators before returning; instead tuples are constructed and returned
only if they’re requested.  (The technical term for this behaviour is
lazy evaluation(1).)

This iterator is intended to be used with iterables that are all of the
same length.  If the iterables are of different lengths, the resulting
stream will be the same length as the shortest iterable.

     zip(['a', 'b'], (1, 2, 3)) =>
       ('a', 1), ('b', 2)

You should avoid doing this, though, because an element may be taken
from the longer iterators and discarded.  This means you can’t go on to
use the iterators further because you risk skipping a discarded element.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Lazy_evaluation


File: python.info,  Node: The itertools module,  Next: The functools module,  Prev: Built-in functions<2>,  Up: Functional Programming HOWTO

9.7.6 The itertools module
--------------------------

The *note itertools: 81. module contains a number of commonly used
iterators as well as functions for combining several iterators.  This
section will introduce the module’s contents by showing small examples.

The module’s functions fall into a few broad classes:

   * Functions that create a new iterator based on an existing iterator.

   * Functions for treating an iterator’s elements as function
     arguments.

   * Functions for selecting portions of an iterator’s output.

   * A function for grouping an iterator’s output.

* Menu:

* Creating new iterators::
* Calling functions on elements::
* Selecting elements::
* Combinatoric functions::
* Grouping elements::


File: python.info,  Node: Creating new iterators,  Next: Calling functions on elements,  Up: The itertools module

9.7.6.1 Creating new iterators
..............................

*note itertools.count(start, step): 12ca. returns an infinite stream of
evenly spaced values.  You can optionally supply the starting number,
which defaults to 0, and the interval between numbers, which defaults to
1:

     itertools.count() =>
       0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...
     itertools.count(10) =>
       10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ...
     itertools.count(10, 5) =>
       10, 15, 20, 25, 30, 35, 40, 45, 50, 55, ...

*note itertools.cycle(iter): 28f6. saves a copy of the contents of a
provided iterable and returns a new iterator that returns its elements
from first to last.  The new iterator will repeat these elements
infinitely.

     itertools.cycle([1, 2, 3, 4, 5]) =>
       1, 2, 3, 4, 5, 1, 2, 3, 4, 5, ...

*note itertools.repeat(elem, [n]): 28f7. returns the provided element
'n' times, or returns the element endlessly if 'n' is not provided.

     itertools.repeat('abc') =>
       abc, abc, abc, abc, abc, abc, abc, abc, abc, abc, ...
     itertools.repeat('abc', 5) =>
       abc, abc, abc, abc, abc

*note itertools.chain(iterA, iterB, ...): 2338. takes an arbitrary
number of iterables as input, and returns all the elements of the first
iterator, then all the elements of the second, and so on, until all of
the iterables have been exhausted.

     itertools.chain(['a', 'b', 'c'], (1, 2, 3)) =>
       a, b, c, 1, 2, 3

*note itertools.islice(iter, [start], stop, [step]): b67. returns a
stream that’s a slice of the iterator.  With a single 'stop' argument,
it will return the first 'stop' elements.  If you supply a starting
index, you’ll get 'stop-start' elements, and if you supply a value for
'step', elements will be skipped accordingly.  Unlike Python’s string
and list slicing, you can’t use negative values for 'start', 'stop', or
'step'.

     itertools.islice(range(10), 8) =>
       0, 1, 2, 3, 4, 5, 6, 7
     itertools.islice(range(10), 2, 8) =>
       2, 3, 4, 5, 6, 7
     itertools.islice(range(10), 2, 8, 2) =>
       2, 4, 6

*note itertools.tee(iter, [n]): 28fb. replicates an iterator; it returns
'n' independent iterators that will all return the contents of the
source iterator.  If you don’t supply a value for 'n', the default is 2.
Replicating iterators requires saving some of the contents of the source
iterator, so this can consume significant memory if the iterator is
large and one of the new iterators is consumed more than the others.

     itertools.tee( itertools.count() ) =>
        iterA, iterB

     where iterA ->
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...

     and   iterB ->
        0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...


File: python.info,  Node: Calling functions on elements,  Next: Selecting elements,  Prev: Creating new iterators,  Up: The itertools module

9.7.6.2 Calling functions on elements
.....................................

The *note operator: 9f. module contains a set of functions corresponding
to Python’s operators.  Some examples are *note operator.add(a, b):
2923. (adds two values), *note operator.ne(a, b): 2913. (same as ‘a !=
b’), and *note operator.attrgetter('id'): e66. (returns a callable that
fetches the ‘.id’ attribute).

*note itertools.starmap(func, iter): 1128. assumes that the iterable
will return a stream of tuples, and calls 'func' using these tuples as
the arguments:

     itertools.starmap(os.path.join,
                       [('/bin', 'python'), ('/usr', 'bin', 'java'),
                        ('/usr', 'bin', 'perl'), ('/usr', 'bin', 'ruby')])
     =>
       /bin/python, /usr/bin/java, /usr/bin/perl, /usr/bin/ruby


File: python.info,  Node: Selecting elements,  Next: Combinatoric functions,  Prev: Calling functions on elements,  Up: The itertools module

9.7.6.3 Selecting elements
..........................

Another group of functions chooses a subset of an iterator’s elements
based on a predicate.

*note itertools.filterfalse(predicate, iter): 2326. is the opposite of
*note filter(): 86b, returning all elements for which the predicate
returns false:

     itertools.filterfalse(is_even, itertools.count()) =>
       1, 3, 5, 7, 9, 11, 13, 15, ...

*note itertools.takewhile(predicate, iter): 28fa. returns elements for
as long as the predicate returns true.  Once the predicate returns
false, the iterator will signal the end of its results.

     def less_than_10(x):
         return x < 10

     itertools.takewhile(less_than_10, itertools.count()) =>
       0, 1, 2, 3, 4, 5, 6, 7, 8, 9

     itertools.takewhile(is_even, itertools.count()) =>
       0

*note itertools.dropwhile(predicate, iter): 28f9. discards elements
while the predicate returns true, and then returns the rest of the
iterable’s results.

     itertools.dropwhile(less_than_10, itertools.count()) =>
       10, 11, 12, 13, 14, 15, 16, 17, 18, 19, ...

     itertools.dropwhile(is_even, itertools.count()) =>
       1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...

*note itertools.compress(data, selectors): 12c9. takes two iterators and
returns only those elements of 'data' for which the corresponding
element of 'selectors' is true, stopping whenever either one is
exhausted:

     itertools.compress([1, 2, 3, 4, 5], [True, True, False, False, True]) =>
        1, 2, 5


File: python.info,  Node: Combinatoric functions,  Next: Grouping elements,  Prev: Selecting elements,  Up: The itertools module

9.7.6.4 Combinatoric functions
..............................

The *note itertools.combinations(iterable, r): 135b. returns an iterator
giving all possible 'r'-tuple combinations of the elements contained in
'iterable'.

     itertools.combinations([1, 2, 3, 4, 5], 2) =>
       (1, 2), (1, 3), (1, 4), (1, 5),
       (2, 3), (2, 4), (2, 5),
       (3, 4), (3, 5),
       (4, 5)

     itertools.combinations([1, 2, 3, 4, 5], 3) =>
       (1, 2, 3), (1, 2, 4), (1, 2, 5), (1, 3, 4), (1, 3, 5), (1, 4, 5),
       (2, 3, 4), (2, 3, 5), (2, 4, 5),
       (3, 4, 5)

The elements within each tuple remain in the same order as 'iterable'
returned them.  For example, the number 1 is always before 2, 3, 4, or 5
in the examples above.  A similar function, *note
itertools.permutations(iterable, r=None): 1a84, removes this constraint
on the order, returning all possible arrangements of length 'r':

     itertools.permutations([1, 2, 3, 4, 5], 2) =>
       (1, 2), (1, 3), (1, 4), (1, 5),
       (2, 1), (2, 3), (2, 4), (2, 5),
       (3, 1), (3, 2), (3, 4), (3, 5),
       (4, 1), (4, 2), (4, 3), (4, 5),
       (5, 1), (5, 2), (5, 3), (5, 4)

     itertools.permutations([1, 2, 3, 4, 5]) =>
       (1, 2, 3, 4, 5), (1, 2, 3, 5, 4), (1, 2, 4, 3, 5),
       ...
       (5, 4, 3, 2, 1)

If you don’t supply a value for 'r' the length of the iterable is used,
meaning that all the elements are permuted.

Note that these functions produce all of the possible combinations by
position and don’t require that the contents of 'iterable' are unique:

     itertools.permutations('aba', 3) =>
       ('a', 'b', 'a'), ('a', 'a', 'b'), ('b', 'a', 'a'),
       ('b', 'a', 'a'), ('a', 'a', 'b'), ('a', 'b', 'a')

The identical tuple ‘('a', 'a', 'b')’ occurs twice, but the two ‘a’
strings came from different positions.

The *note itertools.combinations_with_replacement(iterable, r): 12c8.
function relaxes a different constraint: elements can be repeated within
a single tuple.  Conceptually an element is selected for the first
position of each tuple and then is replaced before the second element is
selected.

     itertools.combinations_with_replacement([1, 2, 3, 4, 5], 2) =>
       (1, 1), (1, 2), (1, 3), (1, 4), (1, 5),
       (2, 2), (2, 3), (2, 4), (2, 5),
       (3, 3), (3, 4), (3, 5),
       (4, 4), (4, 5),
       (5, 5)


File: python.info,  Node: Grouping elements,  Prev: Combinatoric functions,  Up: The itertools module

9.7.6.5 Grouping elements
.........................

The last function I’ll discuss, *note itertools.groupby(iter,
key_func=None): 15aa, is the most complicated.  ‘key_func(elem)’ is a
function that can compute a key value for each element returned by the
iterable.  If you don’t supply a key function, the key is simply each
element itself.

*note groupby(): 15aa. collects all the consecutive elements from the
underlying iterable that have the same key value, and returns a stream
of 2-tuples containing a key value and an iterator for the elements with
that key.

     city_list = [('Decatur', 'AL'), ('Huntsville', 'AL'), ('Selma', 'AL'),
                  ('Anchorage', 'AK'), ('Nome', 'AK'),
                  ('Flagstaff', 'AZ'), ('Phoenix', 'AZ'), ('Tucson', 'AZ'),
                  ...
                 ]

     def get_state(city_state):
         return city_state[1]

     itertools.groupby(city_list, get_state) =>
       ('AL', iterator-1),
       ('AK', iterator-2),
       ('AZ', iterator-3), ...

     where
     iterator-1 =>
       ('Decatur', 'AL'), ('Huntsville', 'AL'), ('Selma', 'AL')
     iterator-2 =>
       ('Anchorage', 'AK'), ('Nome', 'AK')
     iterator-3 =>
       ('Flagstaff', 'AZ'), ('Phoenix', 'AZ'), ('Tucson', 'AZ')

*note groupby(): 15aa. assumes that the underlying iterable’s contents
will already be sorted based on the key.  Note that the returned
iterators also use the underlying iterable, so you have to consume the
results of iterator-1 before requesting iterator-2 and its corresponding
key.


File: python.info,  Node: The functools module,  Next: Small functions and the lambda expression,  Prev: The itertools module,  Up: Functional Programming HOWTO

9.7.7 The functools module
--------------------------

The *note functools: 5f. module contains some higher-order functions.  A
'higher-order function' takes one or more functions as input and returns
a new function.  The most useful tool in this module is the *note
functools.partial(): 417. function.

For programs written in a functional style, you’ll sometimes want to
construct variants of existing functions that have some of the
parameters filled in.  Consider a Python function ‘f(a, b, c)’; you may
wish to create a new function ‘g(b, c)’ that’s equivalent to ‘f(1, b,
c)’; you’re filling in a value for one of ‘f()’’s parameters.  This is
called “partial function application”.

The constructor for *note partial(): 417. takes the arguments
‘(function, arg1, arg2, ..., kwarg1=value1, kwarg2=value2)’.  The
resulting object is callable, so you can just call it to invoke
‘function’ with the filled-in arguments.

Here’s a small but realistic example:

     import functools

     def log(message, subsystem):
         """Write the contents of 'message' to the specified subsystem."""
         print('%s: %s' % (subsystem, message))
         ...

     server_log = functools.partial(log, subsystem='server')
     server_log('Unable to open socket')

*note functools.reduce(func, iter, [initial_value]): 1324. cumulatively
performs an operation on all the iterable’s elements and, therefore,
can’t be applied to infinite iterables.  'func' must be a function that
takes two elements and returns a single value.  ‘functools.reduce()’
takes the first two elements A and B returned by the iterator and
calculates ‘func(A, B)’.  It then requests the third element, C,
calculates ‘func(func(A, B), C)’, combines this result with the fourth
element returned, and continues until the iterable is exhausted.  If the
iterable returns no values at all, a *note TypeError: 2c3. exception is
raised.  If the initial value is supplied, it’s used as a starting point
and ‘func(initial_value, A)’ is the first calculation.

     >>> import operator, functools
     >>> functools.reduce(operator.concat, ['A', 'BB', 'C'])
     'ABBC'
     >>> functools.reduce(operator.concat, [])
     Traceback (most recent call last):
       ...
     TypeError: reduce() of empty sequence with no initial value
     >>> functools.reduce(operator.mul, [1, 2, 3], 1)
     6
     >>> functools.reduce(operator.mul, [], 1)
     1

If you use *note operator.add(): 2923. with *note functools.reduce():
1324, you’ll add up all the elements of the iterable.  This case is so
common that there’s a special built-in called *note sum(): 46d. to
compute it:

     >>> import functools, operator
     >>> functools.reduce(operator.add, [1, 2, 3, 4], 0)
     10
     >>> sum([1, 2, 3, 4])
     10
     >>> sum([])
     0

For many uses of *note functools.reduce(): 1324, though, it can be
clearer to just write the obvious *note for: 2f2. loop:

     import functools
     # Instead of:
     product = functools.reduce(operator.mul, [1, 2, 3], 1)

     # You can write:
     product = 1
     for i in [1, 2, 3]:
         product *= i

A related function is *note itertools.accumulate(iterable,
func=operator.add): a08.  It performs the same calculation, but instead
of returning only the final result, ‘accumulate()’ returns an iterator
that also yields each partial result:

     itertools.accumulate([1, 2, 3, 4, 5]) =>
       1, 3, 6, 10, 15

     itertools.accumulate([1, 2, 3, 4, 5], operator.mul) =>
       1, 2, 6, 24, 120

* Menu:

* The operator module::


File: python.info,  Node: The operator module,  Up: The functools module

9.7.7.1 The operator module
...........................

The *note operator: 9f. module was mentioned earlier.  It contains a set
of functions corresponding to Python’s operators.  These functions are
often useful in functional-style code because they save you from writing
trivial functions that perform a single operation.

Some of the functions in this module are:

   * Math operations: ‘add()’, ‘sub()’, ‘mul()’, ‘floordiv()’, ‘abs()’,
     …

   * Logical operations: ‘not_()’, ‘truth()’.

   * Bitwise operations: ‘and_()’, ‘or_()’, ‘invert()’.

   * Comparisons: ‘eq()’, ‘ne()’, ‘lt()’, ‘le()’, ‘gt()’, and ‘ge()’.

   * Object identity: ‘is_()’, ‘is_not()’.

Consult the operator module’s documentation for a complete list.


File: python.info,  Node: Small functions and the lambda expression,  Next: Revision History and Acknowledgements,  Prev: The functools module,  Up: Functional Programming HOWTO

9.7.8 Small functions and the lambda expression
-----------------------------------------------

When writing functional-style programs, you’ll often need little
functions that act as predicates or that combine elements in some way.

If there’s a Python built-in or a module function that’s suitable, you
don’t need to define a new function at all:

     stripped_lines = [line.strip() for line in lines]
     existing_files = filter(os.path.exists, file_list)

If the function you need doesn’t exist, you need to write it.  One way
to write small functions is to use the *note lambda: 12e4. expression.
‘lambda’ takes a number of parameters and an expression combining these
parameters, and creates an anonymous function that returns the value of
the expression:

     adder = lambda x, y: x+y

     print_assign = lambda name, value: name + '=' + str(value)

An alternative is to just use the ‘def’ statement and define a function
in the usual way:

     def adder(x, y):
         return x + y

     def print_assign(name, value):
         return name + '=' + str(value)

Which alternative is preferable?  That’s a style question; my usual
course is to avoid using ‘lambda’.

One reason for my preference is that ‘lambda’ is quite limited in the
functions it can define.  The result has to be computable as a single
expression, which means you can’t have multiway ‘if... elif... else’
comparisons or ‘try... except’ statements.  If you try to do too much in
a ‘lambda’ statement, you’ll end up with an overly complicated
expression that’s hard to read.  Quick, what’s the following code doing?

     import functools
     total = functools.reduce(lambda a, b: (0, a[1] + b[1]), items)[1]

You can figure it out, but it takes time to disentangle the expression
to figure out what’s going on.  Using a short nested ‘def’ statements
makes things a little bit better:

     import functools
     def combine(a, b):
         return 0, a[1] + b[1]

     total = functools.reduce(combine, items)[1]

But it would be best of all if I had simply used a ‘for’ loop:

     total = 0
     for a, b in items:
         total += b

Or the *note sum(): 46d. built-in and a generator expression:

     total = sum(b for a, b in items)

Many uses of *note functools.reduce(): 1324. are clearer when written as
‘for’ loops.

Fredrik Lundh once suggested the following set of rules for refactoring
uses of ‘lambda’:

  1. Write a lambda function.

  2. Write a comment explaining what the heck that lambda does.

  3. Study the comment for a while, and think of a name that captures
     the essence of the comment.

  4. Convert the lambda to a def statement, using that name.

  5. Remove the comment.

I really like these rules, but you’re free to disagree about whether
this lambda-free style is better.


File: python.info,  Node: Revision History and Acknowledgements,  Next: References<2>,  Prev: Small functions and the lambda expression,  Up: Functional Programming HOWTO

9.7.9 Revision History and Acknowledgements
-------------------------------------------

The author would like to thank the following people for offering
suggestions, corrections and assistance with various drafts of this
article: Ian Bicking, Nick Coghlan, Nick Efford, Raymond Hettinger, Jim
Jewett, Mike Krell, Leandro Lameiro, Jussi Salmela, Collin Winter, Blake
Winton.

Version 0.1: posted June 30 2006.

Version 0.11: posted July 1 2006.  Typo fixes.

Version 0.2: posted July 10 2006.  Merged genexp and listcomp sections
into one.  Typo fixes.

Version 0.21: Added more references suggested on the tutor mailing list.

Version 0.30: Adds a section on the ‘functional’ module written by
Collin Winter; adds short section on the operator module; a few other
edits.


File: python.info,  Node: References<2>,  Prev: Revision History and Acknowledgements,  Up: Functional Programming HOWTO

9.7.10 References
-----------------

* Menu:

* General::
* Python-specific::
* Python documentation::


File: python.info,  Node: General,  Next: Python-specific,  Up: References<2>

9.7.10.1 General
................

'Structure and Interpretation of Computer Programs', by Harold Abelson
and Gerald Jay Sussman with Julie Sussman.  The book can be found at
‘https://mitpress.mit.edu/sicp’.  In this classic textbook of computer
science, chapters 2 and 3 discuss the use of sequences and streams to
organize the data flow inside a program.  The book uses Scheme for its
examples, but many of the design approaches described in these chapters
are applicable to functional-style Python code.

‘https://defmacro.org/2006/06/19/fp.html’: A general introduction to
functional programming that uses Java examples and has a lengthy
historical introduction.

‘https://en.wikipedia.org/wiki/Functional_programming’: General
Wikipedia entry describing functional programming.

‘https://en.wikipedia.org/wiki/Coroutine’: Entry for coroutines.

‘https://en.wikipedia.org/wiki/Partial_application’: Entry for the
concept of partial function application.

‘https://en.wikipedia.org/wiki/Currying’: Entry for the concept of
currying.


File: python.info,  Node: Python-specific,  Next: Python documentation,  Prev: General,  Up: References<2>

9.7.10.2 Python-specific
........................

‘https://gnosis.cx/TPiP/’: The first chapter of David Mertz’s book ‘Text
Processing in Python’ discusses functional programming for text
processing, in the section titled “Utilizing Higher-Order Functions in
Text Processing”.

Mertz also wrote a 3-part series of articles on functional programming
for IBM’s DeveloperWorks site; see part 1(1), part 2(2), and part 3(3),

   ---------- Footnotes ----------

   (1) https://developer.ibm.com/articles/l-prog/

   (2) https://developer.ibm.com/tutorials/l-prog2/

   (3) https://developer.ibm.com/tutorials/l-prog3/


File: python.info,  Node: Python documentation,  Prev: Python-specific,  Up: References<2>

9.7.10.3 Python documentation
.............................

Documentation for the *note itertools: 81. module.

Documentation for the *note functools: 5f. module.

Documentation for the *note operator: 9f. module.

PEP 289(1): “Generator Expressions”

PEP 342(2): “Coroutines via Enhanced Generators” describes the new
generator features in Python 2.5.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0289/

   (2) https://peps.python.org/pep-0342/


File: python.info,  Node: Logging HOWTO,  Next: Logging Cookbook,  Prev: Functional Programming HOWTO,  Up: Python HOWTOs

9.8 Logging HOWTO
=================


Author: Vinay Sajip <vinay_sajip at red-dove dot com>

This page contains tutorial information.  For links to reference
information and a logging cookbook, please see *note Other resources:
53c0.

* Menu:

* Basic Logging Tutorial::
* Advanced Logging Tutorial::
* Logging Levels: Logging Levels<2>.
* Useful Handlers::
* Exceptions raised during logging::
* Using arbitrary objects as messages::
* Optimization::
* Other resources::


File: python.info,  Node: Basic Logging Tutorial,  Next: Advanced Logging Tutorial,  Up: Logging HOWTO

9.8.1 Basic Logging Tutorial
----------------------------

Logging is a means of tracking events that happen when some software
runs.  The software’s developer adds logging calls to their code to
indicate that certain events have occurred.  An event is described by a
descriptive message which can optionally contain variable data (i.e.
data that is potentially different for each occurrence of the event).
Events also have an importance which the developer ascribes to the
event; the importance can also be called the 'level' or 'severity'.

* Menu:

* When to use logging::
* A simple example::
* Logging to a file::
* Logging variable data::
* Changing the format of displayed messages::
* Displaying the date/time in messages::
* Next Steps::


File: python.info,  Node: When to use logging,  Next: A simple example,  Up: Basic Logging Tutorial

9.8.1.1 When to use logging
...........................

You can access logging functionality by creating a logger via ‘logger =
logging.getLogger(__name__)’, and then calling the logger’s *note
debug(): e5d, *note info(): 2e59, *note warning(): 1813, *note error():
2e5b. and *note critical(): e5c. methods.  To determine when to use
logging, and to see which logger methods to use when, see the table
below.  It states, for each of a set of common tasks, the best tool to
use for that task.

Task you want to perform                  The best tool for the task
                                          
-------------------------------------------------------------------------------------
                                          
Display console output for ordinary       *note print(): fae.
usage of a command line script or         
program

Report events that occur during normal    A logger’s *note info(): 2e59. (or
operation of a program (e.g.  for         *note debug(): e5d. method for very
status monitoring or fault                detailed output for diagnostic purposes)
investigation)                            

Issue a warning regarding a particular    *note warnings.warn(): 1569. in library
runtime event                             code if the issue is avoidable and the
                                          client application should be modified to
                                          eliminate the warning
                                          
                                          A logger’s *note warning(): 1813. method
                                          if there is nothing the client
                                          application can do about the situation,
                                          but the event should still be noted
                                          
                                          
Report an error regarding a particular    Raise an exception
runtime event                             

Report suppression of an error without    A logger’s *note error(): 2e5b,
raising an exception (e.g.  error         *note exception(): e5b. or
handler in a long-running server          *note critical(): e5c. method as
process)                                  appropriate for the specific error and
                                          application domain
                                          

The logger methods are named after the level or severity of the events
they are used to track.  The standard levels and their applicability are
described below (in increasing order of severity):

Level              When it’s used
                   
---------------------------------------------------------------------
                   
‘DEBUG’            Detailed information, typically of interest
                   only when diagnosing problems.
                   
                   
‘INFO’             Confirmation that things are working as
                   expected.
                   
                   
‘WARNING’          An indication that something unexpected
                   happened, or indicative of some problem in the
                   near future (e.g.  ‘disk space low’).  The
                   software is still working as expected.
                   
                   
‘ERROR’            Due to a more serious problem, the software has
                   not been able to perform some function.
                   
                   
‘CRITICAL’         A serious error, indicating that the program
                   itself may be unable to continue running.
                   

The default level is ‘WARNING’, which means that only events of this
severity and higher will be tracked, unless the logging package is
configured to do otherwise.

Events that are tracked can be handled in different ways.  The simplest
way of handling tracked events is to print them to the console.  Another
common way is to write them to a disk file.


File: python.info,  Node: A simple example,  Next: Logging to a file,  Prev: When to use logging,  Up: Basic Logging Tutorial

9.8.1.2 A simple example
........................

A very simple example is:

     import logging
     logging.warning('Watch out!')  # will print a message to the console
     logging.info('I told you so')  # will not print anything

If you type these lines into a script and run it, you’ll see:

     WARNING:root:Watch out!

printed out on the console.  The ‘INFO’ message doesn’t appear because
the default level is ‘WARNING’.  The printed message includes the
indication of the level and the description of the event provided in the
logging call, i.e.  ‘Watch out!’.  The actual output can be formatted
quite flexibly if you need that; formatting options will also be
explained later.

Notice that in this example, we use functions directly on the ‘logging’
module, like ‘logging.debug’, rather than creating a logger and calling
functions on it.  These functions operation on the root logger, but can
be useful as they will call *note basicConfig(): a0b. for you if it has
not been called yet, like in this example.  In larger programs you’ll
usually want to control the logging configuration explicitly however -
so for that reason as well as others, it’s better to create loggers and
call their methods.


File: python.info,  Node: Logging to a file,  Next: Logging variable data,  Prev: A simple example,  Up: Basic Logging Tutorial

9.8.1.3 Logging to a file
.........................

A very common situation is that of recording logging events in a file,
so let’s look at that next.  Be sure to try the following in a newly
started Python interpreter, and don’t just continue from the session
described above:

     import logging
     logger = logging.getLogger(__name__)
     logging.basicConfig(filename='example.log', encoding='utf-8', level=logging.DEBUG)
     logger.debug('This message should go to the log file')
     logger.info('So should this')
     logger.warning('And this, too')
     logger.error('And non-ASCII stuff, too, like Øresund and Malmö')

Changed in version 3.9: The 'encoding' argument was added.  In earlier
Python versions, or if not specified, the encoding used is the default
value used by *note open(): 51f.  While not shown in the above example,
an 'errors' argument can also now be passed, which determines how
encoding errors are handled.  For available values and the default, see
the documentation for ‘open()’.

And now if we open the file and look at what we have, we should find the
log messages:

     DEBUG:__main__:This message should go to the log file
     INFO:__main__:So should this
     WARNING:__main__:And this, too
     ERROR:__main__:And non-ASCII stuff, too, like Øresund and Malmö

This example also shows how you can set the logging level which acts as
the threshold for tracking.  In this case, because we set the threshold
to ‘DEBUG’, all of the messages were printed.

If you want to set the logging level from a command-line option such as:

     --log=INFO

and you have the value of the parameter passed for ‘--log’ in some
variable 'loglevel', you can use:

     getattr(logging, loglevel.upper())

to get the value which you’ll pass to *note basicConfig(): a0b. via the
'level' argument.  You may want to error check any user input value,
perhaps as in the following example:

     # assuming loglevel is bound to the string value obtained from the
     # command line argument. Convert to upper case to allow the user to
     # specify --log=DEBUG or --log=debug
     numeric_level = getattr(logging, loglevel.upper(), None)
     if not isinstance(numeric_level, int):
         raise ValueError('Invalid log level: %s' % loglevel)
     logging.basicConfig(level=numeric_level, ...)

The call to *note basicConfig(): a0b. should come 'before' any calls to
a logger’s methods such as *note debug(): e5d, *note info(): 2e59, etc.
Otherwise, that logging event may not be handled in the desired manner.

If you run the above script several times, the messages from successive
runs are appended to the file 'example.log'.  If you want each run to
start afresh, not remembering the messages from earlier runs, you can
specify the 'filemode' argument, by changing the call in the above
example to:

     logging.basicConfig(filename='example.log', filemode='w', level=logging.DEBUG)

The output will be the same as before, but the log file is no longer
appended to, so the messages from earlier runs are lost.


File: python.info,  Node: Logging variable data,  Next: Changing the format of displayed messages,  Prev: Logging to a file,  Up: Basic Logging Tutorial

9.8.1.4 Logging variable data
.............................

To log variable data, use a format string for the event description
message and append the variable data as arguments.  For example:

     import logging
     logging.warning('%s before you %s', 'Look', 'leap!')

will display:

     WARNING:root:Look before you leap!

As you can see, merging of variable data into the event description
message uses the old, %-style of string formatting.  This is for
backwards compatibility: the logging package pre-dates newer formatting
options such as *note str.format(): 624. and *note string.Template: 68a.
These newer formatting options 'are' supported, but exploring them is
outside the scope of this tutorial: see *note Using particular
formatting styles throughout your application: 2e78. for more
information.


File: python.info,  Node: Changing the format of displayed messages,  Next: Displaying the date/time in messages,  Prev: Logging variable data,  Up: Basic Logging Tutorial

9.8.1.5 Changing the format of displayed messages
.................................................

To change the format which is used to display messages, you need to
specify the format you want to use:

     import logging
     logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.DEBUG)
     logging.debug('This message should appear on the console')
     logging.info('So should this')
     logging.warning('And this, too')

which would print:

     DEBUG:This message should appear on the console
     INFO:So should this
     WARNING:And this, too

Notice that the ‘root’ which appeared in earlier examples has
disappeared.  For a full set of things that can appear in format
strings, you can refer to the documentation for *note LogRecord
attributes: 2e58, but for simple usage, you just need the 'levelname'
(severity), 'message' (event description, including variable data) and
perhaps to display when the event occurred.  This is described in the
next section.


File: python.info,  Node: Displaying the date/time in messages,  Next: Next Steps,  Prev: Changing the format of displayed messages,  Up: Basic Logging Tutorial

9.8.1.6 Displaying the date/time in messages
............................................

To display the date and time of an event, you would place ‘%(asctime)s’
in your format string:

     import logging
     logging.basicConfig(format='%(asctime)s %(message)s')
     logging.warning('is when this event was logged.')

which should print something like this:

     2010-12-12 11:41:42,612 is when this event was logged.

The default format for date/time display (shown above) is like ISO8601
or RFC 3339(1).  If you need more control over the formatting of the
date/time, provide a 'datefmt' argument to ‘basicConfig’, as in this
example:

     import logging
     logging.basicConfig(format='%(asctime)s %(message)s', datefmt='%m/%d/%Y %I:%M:%S %p')
     logging.warning('is when this event was logged.')

which would display something like this:

     12/12/2010 11:46:36 AM is when this event was logged.

The format of the 'datefmt' argument is the same as supported by *note
time.strftime(): 122e.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc3339.html


File: python.info,  Node: Next Steps,  Prev: Displaying the date/time in messages,  Up: Basic Logging Tutorial

9.8.1.7 Next Steps
..................

That concludes the basic tutorial.  It should be enough to get you up
and running with logging.  There’s a lot more that the logging package
offers, but to get the best out of it, you’ll need to invest a little
more of your time in reading the following sections.  If you’re ready
for that, grab some of your favourite beverage and carry on.

If your logging needs are simple, then use the above examples to
incorporate logging into your own scripts, and if you run into problems
or don’t understand something, please post a question in the Help
category of the Python discussion forum(1) and you should receive help
before too long.

Still here?  You can carry on reading the next few sections, which
provide a slightly more advanced/in-depth tutorial than the basic one
above.  After that, you can take a look at the *note Logging Cookbook:
123c.

   ---------- Footnotes ----------

   (1) https://discuss.python.org/c/help/7


File: python.info,  Node: Advanced Logging Tutorial,  Next: Logging Levels<2>,  Prev: Basic Logging Tutorial,  Up: Logging HOWTO

9.8.2 Advanced Logging Tutorial
-------------------------------

The logging library takes a modular approach and offers several
categories of components: loggers, handlers, filters, and formatters.

   * Loggers expose the interface that application code directly uses.

   * Handlers send the log records (created by loggers) to the
     appropriate destination.

   * Filters provide a finer grained facility for determining which log
     records to output.

   * Formatters specify the layout of log records in the final output.

Log event information is passed between loggers, handlers, filters and
formatters in a *note LogRecord: 1021. instance.

Logging is performed by calling methods on instances of the *note
Logger: b6a. class (hereafter called 'loggers').  Each instance has a
name, and they are conceptually arranged in a namespace hierarchy using
dots (periods) as separators.  For example, a logger named ‘scan’ is the
parent of loggers ‘scan.text’, ‘scan.html’ and ‘scan.pdf’.  Logger names
can be anything you want, and indicate the area of an application in
which a logged message originates.

A good convention to use when naming loggers is to use a module-level
logger, in each module which uses logging, named as follows:

     logger = logging.getLogger(__name__)

This means that logger names track the package/module hierarchy, and
it’s intuitively obvious where events are logged just from the logger
name.

The root of the hierarchy of loggers is called the root logger.  That’s
the logger used by the functions *note debug(): 2e5a, *note info():
2e83, *note warning(): 2ff, *note error(): 2e97. and *note critical():
2e98, which just call the same-named method of the root logger.  The
functions and the methods have the same signatures.  The root logger’s
name is printed as ‘root’ in the logged output.

It is, of course, possible to log messages to different destinations.
Support is included in the package for writing log messages to files,
HTTP GET/POST locations, email via SMTP, generic sockets, queues, or
OS-specific logging mechanisms such as syslog or the Windows NT event
log.  Destinations are served by 'handler' classes.  You can create your
own log destination class if you have special requirements not met by
any of the built-in handler classes.

By default, no destination is set for any logging messages.  You can
specify a destination (such as console or file) by using *note
basicConfig(): a0b. as in the tutorial examples.  If you call the
functions *note debug(): 2e5a, *note info(): 2e83, *note warning(): 2ff,
*note error(): 2e97. and *note critical(): 2e98, they will check to see
if no destination is set; and if one is not set, they will set a
destination of the console (‘sys.stderr’) and a default format for the
displayed message before delegating to the root logger to do the actual
message output.

The default format set by *note basicConfig(): a0b. for messages is:

     severity:logger name:message

You can change this by passing a format string to *note basicConfig():
a0b. with the 'format' keyword argument.  For all options regarding how
a format string is constructed, see *note Formatter Objects: 2e75.

* Menu:

* Logging Flow::
* Loggers::
* Handlers::
* Formatters::
* Configuring Logging::
* What happens if no configuration is provided::
* Configuring Logging for a Library::


File: python.info,  Node: Logging Flow,  Next: Loggers,  Up: Advanced Logging Tutorial

9.8.2.1 Logging Flow
....................

The flow of log event information in loggers and handlers is illustrated
in the following diagram.

[image src="python-figures/logging_flow.png"]



File: python.info,  Node: Loggers,  Next: Handlers,  Prev: Logging Flow,  Up: Advanced Logging Tutorial

9.8.2.2 Loggers
...............

*note Logger: b6a. objects have a threefold job.  First, they expose
several methods to application code so that applications can log
messages at runtime.  Second, logger objects determine which log
messages to act upon based upon severity (the default filtering
facility) or filter objects.  Third, logger objects pass along relevant
log messages to all interested log handlers.

The most widely used methods on logger objects fall into two categories:
configuration and message sending.

These are the most common configuration methods:

   * *note Logger.setLevel(): 14e2. specifies the lowest-severity log
     message a logger will handle, where debug is the lowest built-in
     severity level and critical is the highest built-in severity.  For
     example, if the severity level is INFO, the logger will handle only
     INFO, WARNING, ERROR, and CRITICAL messages and will ignore DEBUG
     messages.

   * *note Logger.addHandler(): 2e53. and *note Logger.removeHandler():
     2e54. add and remove handler objects from the logger object.
     Handlers are covered in more detail in *note Handlers: 53cd.

   * *note Logger.addFilter(): 2e5c. and *note Logger.removeFilter():
     2e5d. add and remove filter objects from the logger object.
     Filters are covered in more detail in *note Filter Objects: 2e80.

You don’t need to always call these methods on every logger you create.
See the last two paragraphs in this section.

With the logger object configured, the following methods create log
messages:

   * *note Logger.debug(): e5d, *note Logger.info(): 2e59, *note
     Logger.warning(): 1813, *note Logger.error(): 2e5b, and *note
     Logger.critical(): e5c. all create log records with a message and a
     level that corresponds to their respective method names.  The
     message is actually a format string, which may contain the standard
     string substitution syntax of ‘%s’, ‘%d’, ‘%f’, and so on.  The
     rest of their arguments is a list of objects that correspond with
     the substitution fields in the message.  With regard to ‘**kwargs’,
     the logging methods care only about a keyword of ‘exc_info’ and use
     it to determine whether to log exception information.

   * *note Logger.exception(): e5b. creates a log message similar to
     *note Logger.error(): 2e5b.  The difference is that
     ‘Logger.exception()’ dumps a stack trace along with it.  Call this
     method only from an exception handler.

   * *note Logger.log(): e5a. takes a log level as an explicit argument.
     This is a little more verbose for logging messages than using the
     log level convenience methods listed above, but this is how to log
     at custom log levels.

*note getLogger(): 96a. returns a reference to a logger instance with
the specified name if it is provided, or ‘root’ if not.  The names are
period-separated hierarchical structures.  Multiple calls to
‘getLogger()’ with the same name will return a reference to the same
logger object.  Loggers that are further down in the hierarchical list
are children of loggers higher up in the list.  For example, given a
logger with a name of ‘foo’, loggers with names of ‘foo.bar’,
‘foo.bar.baz’, and ‘foo.bam’ are all descendants of ‘foo’.

Loggers have a concept of 'effective level'.  If a level is not
explicitly set on a logger, the level of its parent is used instead as
its effective level.  If the parent has no explicit level set, 'its'
parent is examined, and so on - all ancestors are searched until an
explicitly set level is found.  The root logger always has an explicit
level set (‘WARNING’ by default).  When deciding whether to process an
event, the effective level of the logger is used to determine whether
the event is passed to the logger’s handlers.

Child loggers propagate messages up to the handlers associated with
their ancestor loggers.  Because of this, it is unnecessary to define
and configure handlers for all the loggers an application uses.  It is
sufficient to configure handlers for a top-level logger and create child
loggers as needed.  (You can, however, turn off propagation by setting
the 'propagate' attribute of a logger to ‘False’.)


File: python.info,  Node: Handlers,  Next: Formatters,  Prev: Loggers,  Up: Advanced Logging Tutorial

9.8.2.3 Handlers
................

*note Handler: 14e5. objects are responsible for dispatching the
appropriate log messages (based on the log messages’ severity) to the
handler’s specified destination.  *note Logger: b6a. objects can add
zero or more handler objects to themselves with an *note addHandler():
2e53. method.  As an example scenario, an application may want to send
all log messages to a log file, all log messages of error or higher to
stdout, and all messages of critical to an email address.  This scenario
requires three individual handlers where each handler is responsible for
sending messages of a specific severity to a specific location.

The standard library includes quite a few handler types (see *note
Useful Handlers: 53cf.); the tutorials use mainly *note StreamHandler:
123d. and *note FileHandler: 19f9. in its examples.

There are very few methods in a handler for application developers to
concern themselves with.  The only handler methods that seem relevant
for application developers who are using the built-in handler objects
(that is, not creating custom handlers) are the following configuration
methods:

   * The *note setLevel(): 2e6a. method, just as in logger objects,
     specifies the lowest severity that will be dispatched to the
     appropriate destination.  Why are there two ‘setLevel()’ methods?
     The level set in the logger determines which severity of messages
     it will pass to its handlers.  The level set in each handler
     determines which messages that handler will send on.

   * *note setFormatter(): 2e6b. selects a Formatter object for this
     handler to use.

   * *note addFilter(): 2e6c. and *note removeFilter(): 2e6d.
     respectively configure and deconfigure filter objects on handlers.

Application code should not directly instantiate and use instances of
*note Handler: 14e5.  Instead, the ‘Handler’ class is a base class that
defines the interface that all handlers should have and establishes some
default behavior that child classes can use (or override).


File: python.info,  Node: Formatters,  Next: Configuring Logging,  Prev: Handlers,  Up: Advanced Logging Tutorial

9.8.2.4 Formatters
..................

Formatter objects configure the final order, structure, and contents of
the log message.  Unlike the base *note logging.Handler: 14e5. class,
application code may instantiate formatter classes, although you could
likely subclass the formatter if your application needs special
behavior.  The constructor takes three optional arguments – a message
format string, a date format string and a style indicator.

 -- Method: logging.Formatter.__init__ (fmt=None, datefmt=None,
          style='%')

If there is no message format string, the default is to use the raw
message.  If there is no date format string, the default date format is:

     %Y-%m-%d %H:%M:%S

with the milliseconds tacked on at the end.  The ‘style’ is one of
‘'%'’, ‘'{'’, or ‘'$'’.  If one of these is not specified, then ‘'%'’
will be used.

If the ‘style’ is ‘'%'’, the message format string uses ‘%(<dictionary
key>)s’ styled string substitution; the possible keys are documented in
*note LogRecord attributes: 2e58.  If the style is ‘'{'’, the message
format string is assumed to be compatible with *note str.format(): 624.
(using keyword arguments), while if the style is ‘'$'’ then the message
format string should conform to what is expected by *note
string.Template.substitute(): 1e8d.

Changed in version 3.2: Added the ‘style’ parameter.

The following message format string will log the time in a
human-readable format, the severity of the message, and the contents of
the message, in that order:

     '%(asctime)s - %(levelname)s - %(message)s'

Formatters use a user-configurable function to convert the creation time
of a record to a tuple.  By default, *note time.localtime(): 1548. is
used; to change this for a particular formatter instance, set the
‘converter’ attribute of the instance to a function with the same
signature as ‘time.localtime()’ or *note time.gmtime(): 1205.  To change
it for all formatters, for example if you want all logging times to be
shown in GMT, set the ‘converter’ attribute in the Formatter class (to
‘time.gmtime’ for GMT display).


File: python.info,  Node: Configuring Logging,  Next: What happens if no configuration is provided,  Prev: Formatters,  Up: Advanced Logging Tutorial

9.8.2.5 Configuring Logging
...........................

Programmers can configure logging in three ways:

  1. Creating loggers, handlers, and formatters explicitly using Python
     code that calls the configuration methods listed above.

  2. Creating a logging config file and reading it using the *note
     fileConfig(): b6c. function.

  3. Creating a dictionary of configuration information and passing it
     to the *note dictConfig(): 11f4. function.

For the reference documentation on the last two options, see *note
Configuration functions: 133a.  The following example configures a very
simple logger, a console handler, and a simple formatter using Python
code:

     import logging

     # create logger
     logger = logging.getLogger('simple_example')
     logger.setLevel(logging.DEBUG)

     # create console handler and set level to debug
     ch = logging.StreamHandler()
     ch.setLevel(logging.DEBUG)

     # create formatter
     formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')

     # add formatter to ch
     ch.setFormatter(formatter)

     # add ch to logger
     logger.addHandler(ch)

     # 'application' code
     logger.debug('debug message')
     logger.info('info message')
     logger.warning('warn message')
     logger.error('error message')
     logger.critical('critical message')

Running this module from the command line produces the following output:

     $ python simple_logging_module.py
     2005-03-19 15:10:26,618 - simple_example - DEBUG - debug message
     2005-03-19 15:10:26,620 - simple_example - INFO - info message
     2005-03-19 15:10:26,695 - simple_example - WARNING - warn message
     2005-03-19 15:10:26,697 - simple_example - ERROR - error message
     2005-03-19 15:10:26,773 - simple_example - CRITICAL - critical message

The following Python module creates a logger, handler, and formatter
nearly identical to those in the example listed above, with the only
difference being the names of the objects:

     import logging
     import logging.config

     logging.config.fileConfig('logging.conf')

     # create logger
     logger = logging.getLogger('simpleExample')

     # 'application' code
     logger.debug('debug message')
     logger.info('info message')
     logger.warning('warn message')
     logger.error('error message')
     logger.critical('critical message')

Here is the logging.conf file:

     [loggers]
     keys=root,simpleExample

     [handlers]
     keys=consoleHandler

     [formatters]
     keys=simpleFormatter

     [logger_root]
     level=DEBUG
     handlers=consoleHandler

     [logger_simpleExample]
     level=DEBUG
     handlers=consoleHandler
     qualname=simpleExample
     propagate=0

     [handler_consoleHandler]
     class=StreamHandler
     level=DEBUG
     formatter=simpleFormatter
     args=(sys.stdout,)

     [formatter_simpleFormatter]
     format=%(asctime)s - %(name)s - %(levelname)s - %(message)s

The output is nearly identical to that of the non-config-file-based
example:

     $ python simple_logging_config.py
     2005-03-19 15:38:55,977 - simpleExample - DEBUG - debug message
     2005-03-19 15:38:55,979 - simpleExample - INFO - info message
     2005-03-19 15:38:56,054 - simpleExample - WARNING - warn message
     2005-03-19 15:38:56,055 - simpleExample - ERROR - error message
     2005-03-19 15:38:56,130 - simpleExample - CRITICAL - critical message

You can see that the config file approach has a few advantages over the
Python code approach, mainly separation of configuration and code and
the ability of noncoders to easily modify the logging properties.

     Warning: The *note fileConfig(): b6c. function takes a default
     parameter, ‘disable_existing_loggers’, which defaults to ‘True’ for
     reasons of backward compatibility.  This may or may not be what you
     want, since it will cause any non-root loggers existing before the
     ‘fileConfig()’ call to be disabled unless they (or an ancestor) are
     explicitly named in the configuration.  Please refer to the
     reference documentation for more information, and specify ‘False’
     for this parameter if you wish.

     The dictionary passed to *note dictConfig(): 11f4. can also specify
     a Boolean value with key ‘disable_existing_loggers’, which if not
     specified explicitly in the dictionary also defaults to being
     interpreted as ‘True’.  This leads to the logger-disabling
     behaviour described above, which may not be what you want - in
     which case, provide the key explicitly with a value of ‘False’.

Note that the class names referenced in config files need to be either
relative to the logging module, or absolute values which can be resolved
using normal import mechanisms.  Thus, you could use either *note
WatchedFileHandler: 2ed8. (relative to the logging module) or
‘mypackage.mymodule.MyHandler’ (for a class defined in package
‘mypackage’ and module ‘mymodule’, where ‘mypackage’ is available on the
Python import path).

In Python 3.2, a new means of configuring logging has been introduced,
using dictionaries to hold configuration information.  This provides a
superset of the functionality of the config-file-based approach outlined
above, and is the recommended configuration method for new applications
and deployments.  Because a Python dictionary is used to hold
configuration information, and since you can populate that dictionary
using different means, you have more options for configuration.  For
example, you can use a configuration file in JSON format, or, if you
have access to YAML processing functionality, a file in YAML format, to
populate the configuration dictionary.  Or, of course, you can construct
the dictionary in Python code, receive it in pickled form over a socket,
or use whatever approach makes sense for your application.

Here’s an example of the same configuration as above, in YAML format for
the new dictionary-based approach:

     version: 1
     formatters:
       simple:
         format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
     handlers:
       console:
         class: logging.StreamHandler
         level: DEBUG
         formatter: simple
         stream: ext://sys.stdout
     loggers:
       simpleExample:
         level: DEBUG
         handlers: [console]
         propagate: no
     root:
       level: DEBUG
       handlers: [console]

For more information about logging using a dictionary, see *note
Configuration functions: 133a.


File: python.info,  Node: What happens if no configuration is provided,  Next: Configuring Logging for a Library,  Prev: Configuring Logging,  Up: Advanced Logging Tutorial

9.8.2.6 What happens if no configuration is provided
....................................................

If no logging configuration is provided, it is possible to have a
situation where a logging event needs to be output, but no handlers can
be found to output the event.

The event is output using a ‘handler of last resort’, stored in *note
lastResort: 123f.  This internal handler is not associated with any
logger, and acts like a *note StreamHandler: 123d. which writes the
event description message to the current value of ‘sys.stderr’
(therefore respecting any redirections which may be in effect).  No
formatting is done on the message - just the bare event description
message is printed.  The handler’s level is set to ‘WARNING’, so all
events at this and greater severities will be output.

Changed in version 3.2: For versions of Python prior to 3.2, the
behaviour is as follows:

   * If *note raiseExceptions: 123e. is ‘False’ (production mode), the
     event is silently dropped.

   * If *note raiseExceptions: 123e. is ‘True’ (development mode), a
     message ‘No handlers could be found for logger X.Y.Z’ is printed
     once.

To obtain the pre-3.2 behaviour, *note lastResort: 123f. can be set to
‘None’.


File: python.info,  Node: Configuring Logging for a Library,  Prev: What happens if no configuration is provided,  Up: Advanced Logging Tutorial

9.8.2.7 Configuring Logging for a Library
.........................................

When developing a library which uses logging, you should take care to
document how the library uses logging - for example, the names of
loggers used.  Some consideration also needs to be given to its logging
configuration.  If the using application does not use logging, and
library code makes logging calls, then (as described in the previous
section) events of severity ‘WARNING’ and greater will be printed to
‘sys.stderr’.  This is regarded as the best default behaviour.

If for some reason you 'don’t' want these messages printed in the
absence of any logging configuration, you can attach a do-nothing
handler to the top-level logger for your library.  This avoids the
message being printed, since a handler will always be found for the
library’s events: it just doesn’t produce any output.  If the library
user configures logging for application use, presumably that
configuration will add some handlers, and if levels are suitably
configured then logging calls made in library code will send output to
those handlers, as normal.

A do-nothing handler is included in the logging package: *note
NullHandler: 12cb. (since Python 3.1).  An instance of this handler
could be added to the top-level logger of the logging namespace used by
the library ('if' you want to prevent your library’s logged events being
output to ‘sys.stderr’ in the absence of logging configuration).  If all
logging by a library 'foo' is done using loggers with names matching
‘foo.x’, ‘foo.x.y’, etc.  then the code:

     import logging
     logging.getLogger('foo').addHandler(logging.NullHandler())

should have the desired effect.  If an organisation produces a number of
libraries, then the logger name specified can be ‘orgname.foo’ rather
than just ‘foo’.

     Note: It is strongly advised that you 'do not log to the root
     logger' in your library.  Instead, use a logger with a unique and
     easily identifiable name, such as the ‘__name__’ for your library’s
     top-level package or module.  Logging to the root logger will make
     it difficult or impossible for the application developer to
     configure the logging verbosity or handlers of your library as they
     wish.

     Note: It is strongly advised that you 'do not add any handlers
     other than' *note NullHandler: 12cb. 'to your library’s loggers'.
     This is because the configuration of handlers is the prerogative of
     the application developer who uses your library.  The application
     developer knows their target audience and what handlers are most
     appropriate for their application: if you add handlers ‘under the
     hood’, you might well interfere with their ability to carry out
     unit tests and deliver logs which suit their requirements.


File: python.info,  Node: Logging Levels<2>,  Next: Useful Handlers,  Prev: Advanced Logging Tutorial,  Up: Logging HOWTO

9.8.3 Logging Levels
--------------------

The numeric values of logging levels are given in the following table.
These are primarily of interest if you want to define your own levels,
and need them to have specific values relative to the predefined levels.
If you define a level with the same numeric value, it overwrites the
predefined value; the predefined name is lost.

Level              Numeric value
                   
---------------------------------------
                   
‘CRITICAL’         50
                   
                   
‘ERROR’            40
                   
                   
‘WARNING’          30
                   
                   
‘INFO’             20
                   
                   
‘DEBUG’            10
                   
                   
‘NOTSET’           0
                   

Levels can also be associated with loggers, being set either by the
developer or through loading a saved logging configuration.  When a
logging method is called on a logger, the logger compares its own level
with the level associated with the method call.  If the logger’s level
is higher than the method call’s, no logging message is actually
generated.  This is the basic mechanism controlling the verbosity of
logging output.

Logging messages are encoded as instances of the *note LogRecord: 1021.
class.  When a logger decides to actually log an event, a ‘LogRecord’
instance is created from the logging message.

Logging messages are subjected to a dispatch mechanism through the use
of 'handlers', which are instances of subclasses of the *note Handler:
14e5. class.  Handlers are responsible for ensuring that a logged
message (in the form of a *note LogRecord: 1021.) ends up in a
particular location (or set of locations) which is useful for the target
audience for that message (such as end users, support desk staff, system
administrators, developers).  Handlers are passed ‘LogRecord’ instances
intended for particular destinations.  Each logger can have zero, one or
more handlers associated with it (via the *note addHandler(): 2e53.
method of *note Logger: b6a.).  In addition to any handlers directly
associated with a logger, 'all handlers associated with all ancestors of
the logger' are called to dispatch the message (unless the 'propagate'
flag for a logger is set to a false value, at which point the passing to
ancestor handlers stops).

Just as for loggers, handlers can have levels associated with them.  A
handler’s level acts as a filter in the same way as a logger’s level
does.  If a handler decides to actually dispatch an event, the *note
emit(): 2e73. method is used to send the message to its destination.
Most user-defined subclasses of *note Handler: 14e5. will need to
override this ‘emit()’.

* Menu:

* Custom Levels::


File: python.info,  Node: Custom Levels,  Up: Logging Levels<2>

9.8.3.1 Custom Levels
.....................

Defining your own levels is possible, but should not be necessary, as
the existing levels have been chosen on the basis of practical
experience.  However, if you are convinced that you need custom levels,
great care should be exercised when doing this, and it is possibly 'a
very bad idea to define custom levels if you are developing a library'.
That’s because if multiple library authors all define their own custom
levels, there is a chance that the logging output from such multiple
libraries used together will be difficult for the using developer to
control and/or interpret, because a given numeric value might mean
different things for different libraries.


File: python.info,  Node: Useful Handlers,  Next: Exceptions raised during logging,  Prev: Logging Levels<2>,  Up: Logging HOWTO

9.8.4 Useful Handlers
---------------------

In addition to the base *note Handler: 14e5. class, many useful
subclasses are provided:

  1. *note StreamHandler: 123d. instances send messages to streams
     (file-like objects).

  2. *note FileHandler: 19f9. instances send messages to disk files.

  3. *note BaseRotatingHandler: 2edc. is the base class for handlers
     that rotate log files at a certain point.  It is not meant to be
     instantiated directly.  Instead, use *note RotatingFileHandler:
     16e0. or *note TimedRotatingFileHandler: f9a.

  4. *note RotatingFileHandler: 16e0. instances send messages to disk
     files, with support for maximum log file sizes and log file
     rotation.

  5. *note TimedRotatingFileHandler: f9a. instances send messages to
     disk files, rotating the log file at certain timed intervals.

  6. *note SocketHandler: f9b. instances send messages to TCP/IP
     sockets.  Since 3.4, Unix domain sockets are also supported.

  7. *note DatagramHandler: f9c. instances send messages to UDP sockets.
     Since 3.4, Unix domain sockets are also supported.

  8. *note SMTPHandler: 166d. instances send messages to a designated
     email address.

  9. *note SysLogHandler: 65f. instances send messages to a Unix syslog
     daemon, possibly on a remote machine.

  10. *note NTEventLogHandler: 2f02. instances send messages to a
     Windows NT/2000/XP event log.

  11. *note MemoryHandler: 2ebb. instances send messages to a buffer in
     memory, which is flushed whenever specific criteria are met.

  12. *note HTTPHandler: e5e. instances send messages to an HTTP server
     using either ‘GET’ or ‘POST’ semantics.

  13. *note WatchedFileHandler: 2ed8. instances watch the file they are
     logging to.  If the file changes, it is closed and reopened using
     the file name.  This handler is only useful on Unix-like systems;
     Windows does not support the underlying mechanism used.

  14. *note QueueHandler: 1907. instances send messages to a queue, such
     as those implemented in the *note queue: b6. or *note
     multiprocessing: 94. modules.

  15. *note NullHandler: 12cb. instances do nothing with error messages.
     They are used by library developers who want to use logging, but
     want to avoid the ‘No handlers could be found for logger 'XXX'’
     message which can be displayed if the library user has not
     configured logging.  See *note Configuring Logging for a Library:
     2ed5. for more information.

Added in version 3.1: The *note NullHandler: 12cb. class.

Added in version 3.2: The *note QueueHandler: 1907. class.

The *note NullHandler: 12cb, *note StreamHandler: 123d. and *note
FileHandler: 19f9. classes are defined in the core logging package.  The
other handlers are defined in a sub-module, *note logging.handlers: 89.
(There is also another sub-module, *note logging.config: 88, for
configuration functionality.)

Logged messages are formatted for presentation through instances of the
*note Formatter: 14e6. class.  They are initialized with a format string
suitable for use with the % operator and a dictionary.

For formatting multiple messages in a batch, instances of *note
BufferingFormatter: 2e7c. can be used.  In addition to the format string
(which is applied to each message in the batch), there is provision for
header and trailer format strings.

When filtering based on logger level and/or handler level is not enough,
instances of *note Filter: 1240. can be added to both *note Logger: b6a.
and *note Handler: 14e5. instances (through their *note addFilter():
2e6c. method).  Before deciding to process a message further, both
loggers and handlers consult all their filters for permission.  If any
filter returns a false value, the message is not processed further.

The basic *note Filter: 1240. functionality allows filtering by specific
logger name.  If this feature is used, messages sent to the named logger
and its children are allowed through the filter, and all others dropped.


File: python.info,  Node: Exceptions raised during logging,  Next: Using arbitrary objects as messages,  Prev: Useful Handlers,  Up: Logging HOWTO

9.8.5 Exceptions raised during logging
--------------------------------------

The logging package is designed to swallow exceptions which occur while
logging in production.  This is so that errors which occur while
handling logging events - such as logging misconfiguration, network or
other similar errors - do not cause the application using logging to
terminate prematurely.

*note SystemExit: d69. and *note KeyboardInterrupt: 9dc. exceptions are
never swallowed.  Other exceptions which occur during the *note emit():
2e73. method of a *note Handler: 14e5. subclass are passed to its *note
handleError(): 2e72. method.

The default implementation of *note handleError(): 2e72. in *note
Handler: 14e5. checks to see if a module-level variable, *note
raiseExceptions: 123e, is set.  If set, a traceback is printed to *note
sys.stderr: 943.  If not set, the exception is swallowed.

     Note: The default value of *note raiseExceptions: 123e. is ‘True’.
     This is because during development, you typically want to be
     notified of any exceptions that occur.  It’s advised that you set
     ‘raiseExceptions’ to ‘False’ for production usage.


File: python.info,  Node: Using arbitrary objects as messages,  Next: Optimization,  Prev: Exceptions raised during logging,  Up: Logging HOWTO

9.8.6 Using arbitrary objects as messages
-----------------------------------------

In the preceding sections and examples, it has been assumed that the
message passed when logging the event is a string.  However, this is not
the only possibility.  You can pass an arbitrary object as a message,
and its *note __str__(): 620. method will be called when the logging
system needs to convert it to a string representation.  In fact, if you
want to, you can avoid computing a string representation altogether -
for example, the *note SocketHandler: f9b. emits an event by pickling it
and sending it over the wire.


File: python.info,  Node: Optimization,  Next: Other resources,  Prev: Using arbitrary objects as messages,  Up: Logging HOWTO

9.8.7 Optimization
------------------

Formatting of message arguments is deferred until it cannot be avoided.
However, computing the arguments passed to the logging method can also
be expensive, and you may want to avoid doing it if the logger will just
throw away your event.  To decide what to do, you can call the *note
isEnabledFor(): 133f. method which takes a level argument and returns
true if the event would be created by the Logger for that level of call.
You can write code like this:

     if logger.isEnabledFor(logging.DEBUG):
         logger.debug('Message with %s, %s', expensive_func1(),
                                             expensive_func2())

so that if the logger’s threshold is set above ‘DEBUG’, the calls to
‘expensive_func1’ and ‘expensive_func2’ are never made.

     Note: In some cases, *note isEnabledFor(): 133f. can itself be more
     expensive than you’d like (e.g.  for deeply nested loggers where an
     explicit level is only set high up in the logger hierarchy).  In
     such cases (or if you want to avoid calling a method in tight
     loops), you can cache the result of a call to ‘isEnabledFor()’ in a
     local or instance variable, and use that instead of calling the
     method each time.  Such a cached value would only need to be
     recomputed when the logging configuration changes dynamically while
     the application is running (which is not all that common).

There are other optimizations which can be made for specific
applications which need more precise control over what logging
information is collected.  Here’s a list of things you can do to avoid
processing during logging which you don’t need:

What you don’t want to collect                            How to avoid collecting it
                                                          
------------------------------------------------------------------------------------------------------------------
                                                          
Information about where calls were made from.             Set ‘logging._srcfile’ to ‘None’.  This avoids
                                                          calling *note sys._getframe(): 6e4, which may help to
                                                          speed up your code in environments like PyPy (which
                                                          can’t speed up code that uses ‘sys._getframe()’).
                                                          
                                                          
Threading information.                                    Set ‘logging.logThreads’ to ‘False’.
                                                          
                                                          
Current process ID (*note os.getpid(): 2cfe.)             Set ‘logging.logProcesses’ to ‘False’.
                                                          
                                                          
Current process name when using ‘multiprocessing’ to      Set ‘logging.logMultiprocessing’ to ‘False’.
manage multiple processes.                                

Current *note asyncio.Task: 1be. name when using          Set ‘logging.logAsyncioTasks’ to ‘False’.
‘asyncio’.                                                

Also note that the core logging module only includes the basic handlers.
If you don’t import *note logging.handlers: 89. and *note
logging.config: 88, they won’t take up any memory.


File: python.info,  Node: Other resources,  Prev: Optimization,  Up: Logging HOWTO

9.8.8 Other resources
---------------------

See also
........

Module *note logging: 87.

     API reference for the logging module.

Module *note logging.config: 88.

     Configuration API for the logging module.

Module *note logging.handlers: 89.

     Useful handlers included with the logging module.

*note A logging cookbook: 123c.


File: python.info,  Node: Logging Cookbook,  Next: Regular expression HOWTO,  Prev: Logging HOWTO,  Up: Python HOWTOs

9.9 Logging Cookbook
====================


Author: Vinay Sajip <vinay_sajip at red-dove dot com>

This page contains a number of recipes related to logging, which have
been found useful in the past.  For links to tutorial and reference
information, please see *note Other resources: 53e0.

* Menu:

* Using logging in multiple modules::
* Logging from multiple threads::
* Multiple handlers and formatters::
* Logging to multiple destinations::
* Custom handling of levels::
* Configuration server example::
* Dealing with handlers that block::
* Sending and receiving logging events across a network::
* Adding contextual information to your logging output::
* Use of contextvars::
* Imparting contextual information in handlers::
* Logging to a single file from multiple processes::
* Using file rotation::
* Use of alternative formatting styles::
* Customizing LogRecord::
* Subclassing QueueHandler and QueueListener- a ZeroMQ example::
* Subclassing QueueHandler and QueueListener- a pynng example::
* An example dictionary-based configuration::
* Using a rotator and namer to customize log rotation processing::
* A more elaborate multiprocessing example::
* Inserting a BOM into messages sent to a SysLogHandler::
* Implementing structured logging::
* Customizing handlers with dictConfig(): Customizing handlers with dictConfig.
* Using particular formatting styles throughout your application::
* Configuring filters with dictConfig(): Configuring filters with dictConfig.
* Customized exception formatting::
* Speaking logging messages::
* Buffering logging messages and outputting them conditionally::
* Sending logging messages to email, with buffering: Sending logging messages to email with buffering.
* Formatting times using UTC (GMT) via configuration: Formatting times using UTC GMT via configuration.
* Using a context manager for selective logging::
* A CLI application starter template::
* A Qt GUI for logging::
* Logging to syslog with RFC5424 support::
* How to treat a logger like an output stream::
* How to uniformly handle newlines in logging output::
* Patterns to avoid::
* Other resources: Other resources<2>.


File: python.info,  Node: Using logging in multiple modules,  Next: Logging from multiple threads,  Up: Logging Cookbook

9.9.1 Using logging in multiple modules
---------------------------------------

Multiple calls to ‘logging.getLogger('someLogger')’ return a reference
to the same logger object.  This is true not only within the same
module, but also across modules as long as it is in the same Python
interpreter process.  It is true for references to the same object;
additionally, application code can define and configure a parent logger
in one module and create (but not configure) a child logger in a
separate module, and all logger calls to the child will pass up to the
parent.  Here is a main module:

     import logging
     import auxiliary_module

     # create logger with 'spam_application'
     logger = logging.getLogger('spam_application')
     logger.setLevel(logging.DEBUG)
     # create file handler which logs even debug messages
     fh = logging.FileHandler('spam.log')
     fh.setLevel(logging.DEBUG)
     # create console handler with a higher log level
     ch = logging.StreamHandler()
     ch.setLevel(logging.ERROR)
     # create formatter and add it to the handlers
     formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
     fh.setFormatter(formatter)
     ch.setFormatter(formatter)
     # add the handlers to the logger
     logger.addHandler(fh)
     logger.addHandler(ch)

     logger.info('creating an instance of auxiliary_module.Auxiliary')
     a = auxiliary_module.Auxiliary()
     logger.info('created an instance of auxiliary_module.Auxiliary')
     logger.info('calling auxiliary_module.Auxiliary.do_something')
     a.do_something()
     logger.info('finished auxiliary_module.Auxiliary.do_something')
     logger.info('calling auxiliary_module.some_function()')
     auxiliary_module.some_function()
     logger.info('done with auxiliary_module.some_function()')

Here is the auxiliary module:

     import logging

     # create logger
     module_logger = logging.getLogger('spam_application.auxiliary')

     class Auxiliary:
         def __init__(self):
             self.logger = logging.getLogger('spam_application.auxiliary.Auxiliary')
             self.logger.info('creating an instance of Auxiliary')

         def do_something(self):
             self.logger.info('doing something')
             a = 1 + 1
             self.logger.info('done doing something')

     def some_function():
         module_logger.info('received a call to "some_function"')

The output looks like this:

     2005-03-23 23:47:11,663 - spam_application - INFO -
        creating an instance of auxiliary_module.Auxiliary
     2005-03-23 23:47:11,665 - spam_application.auxiliary.Auxiliary - INFO -
        creating an instance of Auxiliary
     2005-03-23 23:47:11,665 - spam_application - INFO -
        created an instance of auxiliary_module.Auxiliary
     2005-03-23 23:47:11,668 - spam_application - INFO -
        calling auxiliary_module.Auxiliary.do_something
     2005-03-23 23:47:11,668 - spam_application.auxiliary.Auxiliary - INFO -
        doing something
     2005-03-23 23:47:11,669 - spam_application.auxiliary.Auxiliary - INFO -
        done doing something
     2005-03-23 23:47:11,670 - spam_application - INFO -
        finished auxiliary_module.Auxiliary.do_something
     2005-03-23 23:47:11,671 - spam_application - INFO -
        calling auxiliary_module.some_function()
     2005-03-23 23:47:11,672 - spam_application.auxiliary - INFO -
        received a call to 'some_function'
     2005-03-23 23:47:11,673 - spam_application - INFO -
        done with auxiliary_module.some_function()


File: python.info,  Node: Logging from multiple threads,  Next: Multiple handlers and formatters,  Prev: Using logging in multiple modules,  Up: Logging Cookbook

9.9.2 Logging from multiple threads
-----------------------------------

Logging from multiple threads requires no special effort.  The following
example shows logging from the main (initial) thread and another thread:

     import logging
     import threading
     import time

     def worker(arg):
         while not arg['stop']:
             logging.debug('Hi from myfunc')
             time.sleep(0.5)

     def main():
         logging.basicConfig(level=logging.DEBUG, format='%(relativeCreated)6d %(threadName)s %(message)s')
         info = {'stop': False}
         thread = threading.Thread(target=worker, args=(info,))
         thread.start()
         while True:
             try:
                 logging.debug('Hello from main')
                 time.sleep(0.75)
             except KeyboardInterrupt:
                 info['stop'] = True
                 break
         thread.join()

     if __name__ == '__main__':
         main()

When run, the script should print something like the following:

        0 Thread-1 Hi from myfunc
        3 MainThread Hello from main
      505 Thread-1 Hi from myfunc
      755 MainThread Hello from main
     1007 Thread-1 Hi from myfunc
     1507 MainThread Hello from main
     1508 Thread-1 Hi from myfunc
     2010 Thread-1 Hi from myfunc
     2258 MainThread Hello from main
     2512 Thread-1 Hi from myfunc
     3009 MainThread Hello from main
     3013 Thread-1 Hi from myfunc
     3515 Thread-1 Hi from myfunc
     3761 MainThread Hello from main
     4017 Thread-1 Hi from myfunc
     4513 MainThread Hello from main
     4518 Thread-1 Hi from myfunc

This shows the logging output interspersed as one might expect.  This
approach works for more threads than shown here, of course.


File: python.info,  Node: Multiple handlers and formatters,  Next: Logging to multiple destinations,  Prev: Logging from multiple threads,  Up: Logging Cookbook

9.9.3 Multiple handlers and formatters
--------------------------------------

Loggers are plain Python objects.  The *note addHandler(): 2e53. method
has no minimum or maximum quota for the number of handlers you may add.
Sometimes it will be beneficial for an application to log all messages
of all severities to a text file while simultaneously logging errors or
above to the console.  To set this up, simply configure the appropriate
handlers.  The logging calls in the application code will remain
unchanged.  Here is a slight modification to the previous simple
module-based configuration example:

     import logging

     logger = logging.getLogger('simple_example')
     logger.setLevel(logging.DEBUG)
     # create file handler which logs even debug messages
     fh = logging.FileHandler('spam.log')
     fh.setLevel(logging.DEBUG)
     # create console handler with a higher log level
     ch = logging.StreamHandler()
     ch.setLevel(logging.ERROR)
     # create formatter and add it to the handlers
     formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
     ch.setFormatter(formatter)
     fh.setFormatter(formatter)
     # add the handlers to logger
     logger.addHandler(ch)
     logger.addHandler(fh)

     # 'application' code
     logger.debug('debug message')
     logger.info('info message')
     logger.warning('warn message')
     logger.error('error message')
     logger.critical('critical message')

Notice that the ‘application’ code does not care about multiple
handlers.  All that changed was the addition and configuration of a new
handler named 'fh'.

The ability to create new handlers with higher- or lower-severity
filters can be very helpful when writing and testing an application.
Instead of using many ‘print’ statements for debugging, use
‘logger.debug’: Unlike the print statements, which you will have to
delete or comment out later, the logger.debug statements can remain
intact in the source code and remain dormant until you need them again.
At that time, the only change that needs to happen is to modify the
severity level of the logger and/or handler to debug.


File: python.info,  Node: Logging to multiple destinations,  Next: Custom handling of levels,  Prev: Multiple handlers and formatters,  Up: Logging Cookbook

9.9.4 Logging to multiple destinations
--------------------------------------

Let’s say you want to log to console and file with different message
formats and in differing circumstances.  Say you want to log messages
with levels of DEBUG and higher to file, and those messages at level
INFO and higher to the console.  Let’s also assume that the file should
contain timestamps, but the console messages should not.  Here’s how you
can achieve this:

     import logging

     # set up logging to file - see previous section for more details
     logging.basicConfig(level=logging.DEBUG,
                         format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
                         datefmt='%m-%d %H:%M',
                         filename='/tmp/myapp.log',
                         filemode='w')
     # define a Handler which writes INFO messages or higher to the sys.stderr
     console = logging.StreamHandler()
     console.setLevel(logging.INFO)
     # set a format which is simpler for console use
     formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
     # tell the handler to use this format
     console.setFormatter(formatter)
     # add the handler to the root logger
     logging.getLogger().addHandler(console)

     # Now, we can log to the root logger, or any other logger. First the root...
     logging.info('Jackdaws love my big sphinx of quartz.')

     # Now, define a couple of other loggers which might represent areas in your
     # application:

     logger1 = logging.getLogger('myapp.area1')
     logger2 = logging.getLogger('myapp.area2')

     logger1.debug('Quick zephyrs blow, vexing daft Jim.')
     logger1.info('How quickly daft jumping zebras vex.')
     logger2.warning('Jail zesty vixen who grabbed pay from quack.')
     logger2.error('The five boxing wizards jump quickly.')

When you run this, on the console you will see

     root        : INFO     Jackdaws love my big sphinx of quartz.
     myapp.area1 : INFO     How quickly daft jumping zebras vex.
     myapp.area2 : WARNING  Jail zesty vixen who grabbed pay from quack.
     myapp.area2 : ERROR    The five boxing wizards jump quickly.

and in the file you will see something like

     10-22 22:19 root         INFO     Jackdaws love my big sphinx of quartz.
     10-22 22:19 myapp.area1  DEBUG    Quick zephyrs blow, vexing daft Jim.
     10-22 22:19 myapp.area1  INFO     How quickly daft jumping zebras vex.
     10-22 22:19 myapp.area2  WARNING  Jail zesty vixen who grabbed pay from quack.
     10-22 22:19 myapp.area2  ERROR    The five boxing wizards jump quickly.

As you can see, the DEBUG message only shows up in the file.  The other
messages are sent to both destinations.

This example uses console and file handlers, but you can use any number
and combination of handlers you choose.

Note that the above choice of log filename ‘/tmp/myapp.log’ implies use
of a standard location for temporary files on POSIX systems.  On
Windows, you may need to choose a different directory name for the log -
just ensure that the directory exists and that you have the permissions
to create and update files in it.


File: python.info,  Node: Custom handling of levels,  Next: Configuration server example,  Prev: Logging to multiple destinations,  Up: Logging Cookbook

9.9.5 Custom handling of levels
-------------------------------

Sometimes, you might want to do something slightly different from the
standard handling of levels in handlers, where all levels above a
threshold get processed by a handler.  To do this, you need to use
filters.  Let’s look at a scenario where you want to arrange things as
follows:

   * Send messages of severity ‘INFO’ and ‘WARNING’ to ‘sys.stdout’

   * Send messages of severity ‘ERROR’ and above to ‘sys.stderr’

   * Send messages of severity ‘DEBUG’ and above to file ‘app.log’

Suppose you configure logging with the following JSON:

     {
         "version": 1,
         "disable_existing_loggers": false,
         "formatters": {
             "simple": {
                 "format": "%(levelname)-8s - %(message)s"
             }
         },
         "handlers": {
             "stdout": {
                 "class": "logging.StreamHandler",
                 "level": "INFO",
                 "formatter": "simple",
                 "stream": "ext://sys.stdout"
             },
             "stderr": {
                 "class": "logging.StreamHandler",
                 "level": "ERROR",
                 "formatter": "simple",
                 "stream": "ext://sys.stderr"
             },
             "file": {
                 "class": "logging.FileHandler",
                 "formatter": "simple",
                 "filename": "app.log",
                 "mode": "w"
             }
         },
         "root": {
             "level": "DEBUG",
             "handlers": [
                 "stderr",
                 "stdout",
                 "file"
             ]
         }
     }

This configuration does 'almost' what we want, except that ‘sys.stdout’
would show messages of severity ‘ERROR’ and only events of this severity
and higher will be tracked as well as ‘INFO’ and ‘WARNING’ messages.  To
prevent this, we can set up a filter which excludes those messages and
add it to the relevant handler.  This can be configured by adding a
‘filters’ section parallel to ‘formatters’ and ‘handlers’:

     {
         "filters": {
             "warnings_and_below": {
                 "()" : "__main__.filter_maker",
                 "level": "WARNING"
             }
         }
     }

and changing the section on the ‘stdout’ handler to add it:

     {
         "stdout": {
             "class": "logging.StreamHandler",
             "level": "INFO",
             "formatter": "simple",
             "stream": "ext://sys.stdout",
             "filters": ["warnings_and_below"]
         }
     }

A filter is just a function, so we can define the ‘filter_maker’ (a
factory function) as follows:

     def filter_maker(level):
         level = getattr(logging, level)

         def filter(record):
             return record.levelno <= level

         return filter

This converts the string argument passed in to a numeric level, and
returns a function which only returns ‘True’ if the level of the passed
in record is at or below the specified level.  Note that in this example
I have defined the ‘filter_maker’ in a test script ‘main.py’ that I run
from the command line, so its module will be ‘__main__’ - hence the
‘__main__.filter_maker’ in the filter configuration.  You will need to
change that if you define it in a different module.

With the filter added, we can run ‘main.py’, which in full is:

     import json
     import logging
     import logging.config

     CONFIG = '''
     {
         "version": 1,
         "disable_existing_loggers": false,
         "formatters": {
             "simple": {
                 "format": "%(levelname)-8s - %(message)s"
             }
         },
         "filters": {
             "warnings_and_below": {
                 "()" : "__main__.filter_maker",
                 "level": "WARNING"
             }
         },
         "handlers": {
             "stdout": {
                 "class": "logging.StreamHandler",
                 "level": "INFO",
                 "formatter": "simple",
                 "stream": "ext://sys.stdout",
                 "filters": ["warnings_and_below"]
             },
             "stderr": {
                 "class": "logging.StreamHandler",
                 "level": "ERROR",
                 "formatter": "simple",
                 "stream": "ext://sys.stderr"
             },
             "file": {
                 "class": "logging.FileHandler",
                 "formatter": "simple",
                 "filename": "app.log",
                 "mode": "w"
             }
         },
         "root": {
             "level": "DEBUG",
             "handlers": [
                 "stderr",
                 "stdout",
                 "file"
             ]
         }
     }
     '''

     def filter_maker(level):
         level = getattr(logging, level)

         def filter(record):
             return record.levelno <= level

         return filter

     logging.config.dictConfig(json.loads(CONFIG))
     logging.debug('A DEBUG message')
     logging.info('An INFO message')
     logging.warning('A WARNING message')
     logging.error('An ERROR message')
     logging.critical('A CRITICAL message')

And after running it like this:

     python main.py 2>stderr.log >stdout.log

We can see the results are as expected:

     $ more *.log
     ::::::::::::::
     app.log
     ::::::::::::::
     DEBUG    - A DEBUG message
     INFO     - An INFO message
     WARNING  - A WARNING message
     ERROR    - An ERROR message
     CRITICAL - A CRITICAL message
     ::::::::::::::
     stderr.log
     ::::::::::::::
     ERROR    - An ERROR message
     CRITICAL - A CRITICAL message
     ::::::::::::::
     stdout.log
     ::::::::::::::
     INFO     - An INFO message
     WARNING  - A WARNING message


File: python.info,  Node: Configuration server example,  Next: Dealing with handlers that block,  Prev: Custom handling of levels,  Up: Logging Cookbook

9.9.6 Configuration server example
----------------------------------

Here is an example of a module using the logging configuration server:

     import logging
     import logging.config
     import time
     import os

     # read initial config file
     logging.config.fileConfig('logging.conf')

     # create and start listener on port 9999
     t = logging.config.listen(9999)
     t.start()

     logger = logging.getLogger('simpleExample')

     try:
         # loop through logging calls to see the difference
         # new configurations make, until Ctrl+C is pressed
         while True:
             logger.debug('debug message')
             logger.info('info message')
             logger.warning('warn message')
             logger.error('error message')
             logger.critical('critical message')
             time.sleep(5)
     except KeyboardInterrupt:
         # cleanup
         logging.config.stopListening()
         t.join()

And here is a script that takes a filename and sends that file to the
server, properly preceded with the binary-encoded length, as the new
logging configuration:

     #!/usr/bin/env python
     import socket, sys, struct

     with open(sys.argv[1], 'rb') as f:
         data_to_send = f.read()

     HOST = 'localhost'
     PORT = 9999
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     print('connecting...')
     s.connect((HOST, PORT))
     print('sending config...')
     s.send(struct.pack('>L', len(data_to_send)))
     s.send(data_to_send)
     s.close()
     print('complete')


File: python.info,  Node: Dealing with handlers that block,  Next: Sending and receiving logging events across a network,  Prev: Configuration server example,  Up: Logging Cookbook

9.9.7 Dealing with handlers that block
--------------------------------------

Sometimes you have to get your logging handlers to do their work without
blocking the thread you’re logging from.  This is common in web
applications, though of course it also occurs in other scenarios.

A common culprit which demonstrates sluggish behaviour is the *note
SMTPHandler: 166d.: sending emails can take a long time, for a number of
reasons outside the developer’s control (for example, a poorly
performing mail or network infrastructure).  But almost any
network-based handler can block: Even a *note SocketHandler: f9b.
operation may do a DNS query under the hood which is too slow (and this
query can be deep in the socket library code, below the Python layer,
and outside your control).

One solution is to use a two-part approach.  For the first part, attach
only a *note QueueHandler: 1907. to those loggers which are accessed
from performance-critical threads.  They simply write to their queue,
which can be sized to a large enough capacity or initialized with no
upper bound to their size.  The write to the queue will typically be
accepted quickly, though you will probably need to catch the *note
queue.Full: 3369. exception as a precaution in your code.  If you are a
library developer who has performance-critical threads in their code, be
sure to document this (together with a suggestion to attach only
‘QueueHandlers’ to your loggers) for the benefit of other developers who
will use your code.

The second part of the solution is *note QueueListener: e5f, which has
been designed as the counterpart to *note QueueHandler: 1907.  A
‘QueueListener’ is very simple: it’s passed a queue and some handlers,
and it fires up an internal thread which listens to its queue for
LogRecords sent from ‘QueueHandlers’ (or any other source of
‘LogRecords’, for that matter).  The ‘LogRecords’ are removed from the
queue and passed to the handlers for processing.

The advantage of having a separate *note QueueListener: e5f. class is
that you can use the same instance to service multiple ‘QueueHandlers’.
This is more resource-friendly than, say, having threaded versions of
the existing handler classes, which would eat up one thread per handler
for no particular benefit.

An example of using these two classes follows (imports omitted):

     que = queue.Queue(-1)  # no limit on size
     queue_handler = QueueHandler(que)
     handler = logging.StreamHandler()
     listener = QueueListener(que, handler)
     root = logging.getLogger()
     root.addHandler(queue_handler)
     formatter = logging.Formatter('%(threadName)s: %(message)s')
     handler.setFormatter(formatter)
     listener.start()
     # The log output will display the thread which generated
     # the event (the main thread) rather than the internal
     # thread which monitors the internal queue. This is what
     # you want to happen.
     root.warning('Look out!')
     listener.stop()

which, when run, will produce:

     MainThread: Look out!

     Note: Although the earlier discussion wasn’t specifically talking
     about async code, but rather about slow logging handlers, it should
     be noted that when logging from async code, network and even file
     handlers could lead to problems (blocking the event loop) because
     some logging is done from *note asyncio: a. internals.  It might be
     best, if any async code is used in an application, to use the above
     approach for logging, so that any blocking code runs only in the
     ‘QueueListener’ thread.

Changed in version 3.5: Prior to Python 3.5, the *note QueueListener:
e5f. always passed every message received from the queue to every
handler it was initialized with.  (This was because it was assumed that
level filtering was all done on the other side, where the queue is
filled.)  From 3.5 onwards, this behaviour can be changed by passing a
keyword argument ‘respect_handler_level=True’ to the listener’s
constructor.  When this is done, the listener compares the level of each
message with the handler’s level, and only passes a message to a handler
if it’s appropriate to do so.


File: python.info,  Node: Sending and receiving logging events across a network,  Next: Adding contextual information to your logging output,  Prev: Dealing with handlers that block,  Up: Logging Cookbook

9.9.8 Sending and receiving logging events across a network
-----------------------------------------------------------

Let’s say you want to send logging events across a network, and handle
them at the receiving end.  A simple way of doing this is attaching a
*note SocketHandler: f9b. instance to the root logger at the sending
end:

     import logging, logging.handlers

     rootLogger = logging.getLogger()
     rootLogger.setLevel(logging.DEBUG)
     socketHandler = logging.handlers.SocketHandler('localhost',
                         logging.handlers.DEFAULT_TCP_LOGGING_PORT)
     # don't bother with a formatter, since a socket handler sends the event as
     # an unformatted pickle
     rootLogger.addHandler(socketHandler)

     # Now, we can log to the root logger, or any other logger. First the root...
     logging.info('Jackdaws love my big sphinx of quartz.')

     # Now, define a couple of other loggers which might represent areas in your
     # application:

     logger1 = logging.getLogger('myapp.area1')
     logger2 = logging.getLogger('myapp.area2')

     logger1.debug('Quick zephyrs blow, vexing daft Jim.')
     logger1.info('How quickly daft jumping zebras vex.')
     logger2.warning('Jail zesty vixen who grabbed pay from quack.')
     logger2.error('The five boxing wizards jump quickly.')

At the receiving end, you can set up a receiver using the *note
socketserver: cd. module.  Here is a basic working example:

     import pickle
     import logging
     import logging.handlers
     import socketserver
     import struct


     class LogRecordStreamHandler(socketserver.StreamRequestHandler):
         """Handler for a streaming logging request.

         This basically logs the record using whatever logging policy is
         configured locally.
         """

         def handle(self):
             """
             Handle multiple requests - each expected to be a 4-byte length,
             followed by the LogRecord in pickle format. Logs the record
             according to whatever policy is configured locally.
             """
             while True:
                 chunk = self.connection.recv(4)
                 if len(chunk) < 4:
                     break
                 slen = struct.unpack('>L', chunk)[0]
                 chunk = self.connection.recv(slen)
                 while len(chunk) < slen:
                     chunk = chunk + self.connection.recv(slen - len(chunk))
                 obj = self.unPickle(chunk)
                 record = logging.makeLogRecord(obj)
                 self.handleLogRecord(record)

         def unPickle(self, data):
             return pickle.loads(data)

         def handleLogRecord(self, record):
             # if a name is specified, we use the named logger rather than the one
             # implied by the record.
             if self.server.logname is not None:
                 name = self.server.logname
             else:
                 name = record.name
             logger = logging.getLogger(name)
             # N.B. EVERY record gets logged. This is because Logger.handle
             # is normally called AFTER logger-level filtering. If you want
             # to do filtering, do it at the client end to save wasting
             # cycles and network bandwidth!
             logger.handle(record)

     class LogRecordSocketReceiver(socketserver.ThreadingTCPServer):
         """
         Simple TCP socket-based logging receiver suitable for testing.
         """

         allow_reuse_address = True

         def __init__(self, host='localhost',
                      port=logging.handlers.DEFAULT_TCP_LOGGING_PORT,
                      handler=LogRecordStreamHandler):
             socketserver.ThreadingTCPServer.__init__(self, (host, port), handler)
             self.abort = 0
             self.timeout = 1
             self.logname = None

         def serve_until_stopped(self):
             import select
             abort = 0
             while not abort:
                 rd, wr, ex = select.select([self.socket.fileno()],
                                            [], [],
                                            self.timeout)
                 if rd:
                     self.handle_request()
                 abort = self.abort

     def main():
         logging.basicConfig(
             format='%(relativeCreated)5d %(name)-15s %(levelname)-8s %(message)s')
         tcpserver = LogRecordSocketReceiver()
         print('About to start TCP server...')
         tcpserver.serve_until_stopped()

     if __name__ == '__main__':
         main()

First run the server, and then the client.  On the client side, nothing
is printed on the console; on the server side, you should see something
like:

     About to start TCP server...
        59 root            INFO     Jackdaws love my big sphinx of quartz.
        59 myapp.area1     DEBUG    Quick zephyrs blow, vexing daft Jim.
        69 myapp.area1     INFO     How quickly daft jumping zebras vex.
        69 myapp.area2     WARNING  Jail zesty vixen who grabbed pay from quack.
        69 myapp.area2     ERROR    The five boxing wizards jump quickly.

Note that there are some security issues with pickle in some scenarios.
If these affect you, you can use an alternative serialization scheme by
overriding the *note makePickle(): 2ef3. method and implementing your
alternative there, as well as adapting the above script to use your
alternative serialization.

* Menu:

* Running a logging socket listener in production::


File: python.info,  Node: Running a logging socket listener in production,  Up: Sending and receiving logging events across a network

9.9.8.1 Running a logging socket listener in production
.......................................................

To run a logging listener in production, you may need to use a
process-management tool such as Supervisor(1).  Here is a Gist(2) which
provides the bare-bones files to run the above functionality using
Supervisor.  It consists of the following files:

File                          Purpose
                              
---------------------------------------------------------------------------------------
                              
‘prepare.sh’                  A Bash script to prepare the environment for testing
                              
                              
‘supervisor.conf’             The Supervisor configuration file, which has entries
                              for the listener and a multi-process web application
                              
                              
‘ensure_app.sh’               A Bash script to ensure that Supervisor is running
                              with the above configuration
                              
                              
‘log_listener.py’             The socket listener program which receives log events
                              and records them to a file
                              
                              
‘main.py’                     A simple web application which performs logging via a
                              socket connected to the listener
                              
                              
‘webapp.json’                 A JSON configuration file for the web application
                              
                              
‘client.py’                   A Python script to exercise the web application
                              

The web application uses Gunicorn(3), which is a popular web application
server that starts multiple worker processes to handle requests.  This
example setup shows how the workers can write to the same log file
without conflicting with one another — they all go through the socket
listener.

To test these files, do the following in a POSIX environment:

  1. Download the Gist(4) as a ZIP archive using the Download ZIP
     button.

  2. Unzip the above files from the archive into a scratch directory.

  3. In the scratch directory, run ‘bash prepare.sh’ to get things
     ready.  This creates a ‘run’ subdirectory to contain
     Supervisor-related and log files, and a ‘venv’ subdirectory to
     contain a virtual environment into which ‘bottle’, ‘gunicorn’ and
     ‘supervisor’ are installed.

  4. Run ‘bash ensure_app.sh’ to ensure that Supervisor is running with
     the above configuration.

  5. Run ‘venv/bin/python client.py’ to exercise the web application,
     which will lead to records being written to the log.

  6. Inspect the log files in the ‘run’ subdirectory.  You should see
     the most recent log lines in files matching the pattern ‘app.log*’.
     They won’t be in any particular order, since they have been handled
     concurrently by different worker processes in a non-deterministic
     way.

  7. You can shut down the listener and the web application by running
     ‘venv/bin/supervisorctl -c supervisor.conf shutdown’.

You may need to tweak the configuration files in the unlikely event that
the configured ports clash with something else in your test environment.

The default configuration uses a TCP socket on port 9020.  You can use a
Unix Domain socket instead of a TCP socket by doing the following:

  1. In ‘listener.json’, add a ‘socket’ key with the path to the domain
     socket you want to use.  If this key is present, the listener
     listens on the corresponding domain socket and not on a TCP socket
     (the ‘port’ key is ignored).

  2. In ‘webapp.json’, change the socket handler configuration
     dictionary so that the ‘host’ value is the path to the domain
     socket, and set the ‘port’ value to ‘null’.

   ---------- Footnotes ----------

   (1) http://supervisord.org/

   (2) https://gist.github.com/vsajip/4b227eeec43817465ca835ca66f75e2b

   (3) https://gunicorn.org/

   (4) https://gist.github.com/vsajip/4b227eeec43817465ca835ca66f75e2b


File: python.info,  Node: Adding contextual information to your logging output,  Next: Use of contextvars,  Prev: Sending and receiving logging events across a network,  Up: Logging Cookbook

9.9.9 Adding contextual information to your logging output
----------------------------------------------------------

Sometimes you want logging output to contain contextual information in
addition to the parameters passed to the logging call.  For example, in
a networked application, it may be desirable to log client-specific
information in the log (e.g.  remote client’s username, or IP address).
Although you could use the 'extra' parameter to achieve this, it’s not
always convenient to pass the information in this way.  While it might
be tempting to create *note Logger: b6a. instances on a per-connection
basis, this is not a good idea because these instances are not garbage
collected.  While this is not a problem in practice, when the number of
‘Logger’ instances is dependent on the level of granularity you want to
use in logging an application, it could be hard to manage if the number
of ‘Logger’ instances becomes effectively unbounded.

* Menu:

* Using LoggerAdapters to impart contextual information::
* Using Filters to impart contextual information::


File: python.info,  Node: Using LoggerAdapters to impart contextual information,  Next: Using Filters to impart contextual information,  Up: Adding contextual information to your logging output

9.9.9.1 Using LoggerAdapters to impart contextual information
.............................................................

An easy way in which you can pass contextual information to be output
along with logging event information is to use the *note LoggerAdapter:
133e. class.  This class is designed to look like a *note Logger: b6a,
so that you can call *note debug(): 2e5a, *note info(): 2e83, *note
warning(): 2ff, *note error(): 2e97, *note exception(): 14e3, *note
critical(): 2e98. and *note log(): 2e99.  These methods have the same
signatures as their counterparts in ‘Logger’, so you can use the two
types of instances interchangeably.

When you create an instance of *note LoggerAdapter: 133e, you pass it a
*note Logger: b6a. instance and a dict-like object which contains your
contextual information.  When you call one of the logging methods on an
instance of ‘LoggerAdapter’, it delegates the call to the underlying
instance of ‘Logger’ passed to its constructor, and arranges to pass the
contextual information in the delegated call.  Here’s a snippet from the
code of ‘LoggerAdapter’:

     def debug(self, msg, /, *args, **kwargs):
         """
         Delegate a debug call to the underlying logger, after adding
         contextual information from this adapter instance.
         """
         msg, kwargs = self.process(msg, kwargs)
         self.logger.debug(msg, *args, **kwargs)

The *note process(): 2e90. method of *note LoggerAdapter: 133e. is where
the contextual information is added to the logging output.  It’s passed
the message and keyword arguments of the logging call, and it passes
back (potentially) modified versions of these to use in the call to the
underlying logger.  The default implementation of this method leaves the
message alone, but inserts an ‘extra’ key in the keyword argument whose
value is the dict-like object passed to the constructor.  Of course, if
you had passed an ‘extra’ keyword argument in the call to the adapter,
it will be silently overwritten.

The advantage of using ‘extra’ is that the values in the dict-like
object are merged into the *note LogRecord: 1021. instance’s __dict__,
allowing you to use customized strings with your *note Formatter: 14e6.
instances which know about the keys of the dict-like object.  If you
need a different method, e.g.  if you want to prepend or append the
contextual information to the message string, you just need to subclass
*note LoggerAdapter: 133e. and override *note process(): 2e90. to do
what you need.  Here is a simple example:

     class CustomAdapter(logging.LoggerAdapter):
         """
         This example adapter expects the passed in dict-like object to have a
         'connid' key, whose value in brackets is prepended to the log message.
         """
         def process(self, msg, kwargs):
             return '[%s] %s' % (self.extra['connid'], msg), kwargs

which you can use like this:

     logger = logging.getLogger(__name__)
     adapter = CustomAdapter(logger, {'connid': some_conn_id})

Then any events that you log to the adapter will have the value of
‘some_conn_id’ prepended to the log messages.

* Menu:

* Using objects other than dicts to pass contextual information::


File: python.info,  Node: Using objects other than dicts to pass contextual information,  Up: Using LoggerAdapters to impart contextual information

9.9.9.2 Using objects other than dicts to pass contextual information
.....................................................................

You don’t need to pass an actual dict to a *note LoggerAdapter: 133e. -
you could pass an instance of a class which implements ‘__getitem__’ and
‘__iter__’ so that it looks like a dict to logging.  This would be
useful if you want to generate values dynamically (whereas the values in
a dict would be constant).


File: python.info,  Node: Using Filters to impart contextual information,  Prev: Using LoggerAdapters to impart contextual information,  Up: Adding contextual information to your logging output

9.9.9.3 Using Filters to impart contextual information
......................................................

You can also add contextual information to log output using a
user-defined *note Filter: 1240.  ‘Filter’ instances are allowed to
modify the ‘LogRecords’ passed to them, including adding additional
attributes which can then be output using a suitable format string, or
if needed a custom *note Formatter: 14e6.

For example in a web application, the request being processed (or at
least, the interesting parts of it) can be stored in a threadlocal
(*note threading.local: 1650.) variable, and then accessed from a
‘Filter’ to add, say, information from the request - say, the remote IP
address and remote user’s username - to the ‘LogRecord’, using the
attribute names ‘ip’ and ‘user’ as in the ‘LoggerAdapter’ example above.
In that case, the same format string can be used to get similar output
to that shown above.  Here’s an example script:

     import logging
     from random import choice

     class ContextFilter(logging.Filter):
         """
         This is a filter which injects contextual information into the log.

         Rather than use actual contextual information, we just use random
         data in this demo.
         """

         USERS = ['jim', 'fred', 'sheila']
         IPS = ['123.231.231.123', '127.0.0.1', '192.168.0.1']

         def filter(self, record):

             record.ip = choice(ContextFilter.IPS)
             record.user = choice(ContextFilter.USERS)
             return True

     if __name__ == '__main__':
         levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL)
         logging.basicConfig(level=logging.DEBUG,
                             format='%(asctime)-15s %(name)-5s %(levelname)-8s IP: %(ip)-15s User: %(user)-8s %(message)s')
         a1 = logging.getLogger('a.b.c')
         a2 = logging.getLogger('d.e.f')

         f = ContextFilter()
         a1.addFilter(f)
         a2.addFilter(f)
         a1.debug('A debug message')
         a1.info('An info message with %s', 'some parameters')
         for x in range(10):
             lvl = choice(levels)
             lvlname = logging.getLevelName(lvl)
             a2.log(lvl, 'A message at %s level with %d %s', lvlname, 2, 'parameters')

which, when run, produces something like:

     2010-09-06 22:38:15,292 a.b.c DEBUG    IP: 123.231.231.123 User: fred     A debug message
     2010-09-06 22:38:15,300 a.b.c INFO     IP: 192.168.0.1     User: sheila   An info message with some parameters
     2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 127.0.0.1       User: sheila   A message at CRITICAL level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f ERROR    IP: 127.0.0.1       User: jim      A message at ERROR level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f DEBUG    IP: 127.0.0.1       User: sheila   A message at DEBUG level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f ERROR    IP: 123.231.231.123 User: fred     A message at ERROR level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 192.168.0.1     User: jim      A message at CRITICAL level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f CRITICAL IP: 127.0.0.1       User: sheila   A message at CRITICAL level with 2 parameters
     2010-09-06 22:38:15,300 d.e.f DEBUG    IP: 192.168.0.1     User: jim      A message at DEBUG level with 2 parameters
     2010-09-06 22:38:15,301 d.e.f ERROR    IP: 127.0.0.1       User: sheila   A message at ERROR level with 2 parameters
     2010-09-06 22:38:15,301 d.e.f DEBUG    IP: 123.231.231.123 User: fred     A message at DEBUG level with 2 parameters
     2010-09-06 22:38:15,301 d.e.f INFO     IP: 123.231.231.123 User: fred     A message at INFO level with 2 parameters


File: python.info,  Node: Use of contextvars,  Next: Imparting contextual information in handlers,  Prev: Adding contextual information to your logging output,  Up: Logging Cookbook

9.9.10 Use of ‘contextvars’
---------------------------

Since Python 3.7, the *note contextvars: 24. module has provided
context-local storage which works for both *note threading: ed. and
*note asyncio: a. processing needs.  This type of storage may thus be
generally preferable to thread-locals.  The following example shows how,
in a multi-threaded environment, logs can populated with contextual
information such as, for example, request attributes handled by web
applications.

For the purposes of illustration, say that you have different web
applications, each independent of the other but running in the same
Python process and using a library common to them.  How can each of
these applications have their own log, where all logging messages from
the library (and other request processing code) are directed to the
appropriate application’s log file, while including in the log
additional contextual information such as client IP, HTTP request method
and client username?

Let’s assume that the library can be simulated by the following code:

     # webapplib.py
     import logging
     import time

     logger = logging.getLogger(__name__)

     def useful():
         # Just a representative event logged from the library
         logger.debug('Hello from webapplib!')
         # Just sleep for a bit so other threads get to run
         time.sleep(0.01)

We can simulate the multiple web applications by means of two simple
classes, ‘Request’ and ‘WebApp’.  These simulate how real threaded web
applications work - each request is handled by a thread:

     # main.py
     import argparse
     from contextvars import ContextVar
     import logging
     import os
     from random import choice
     import threading
     import webapplib

     logger = logging.getLogger(__name__)
     root = logging.getLogger()
     root.setLevel(logging.DEBUG)

     class Request:
         """
         A simple dummy request class which just holds dummy HTTP request method,
         client IP address and client username
         """
         def __init__(self, method, ip, user):
             self.method = method
             self.ip = ip
             self.user = user

     # A dummy set of requests which will be used in the simulation - we'll just pick
     # from this list randomly. Note that all GET requests are from 192.168.2.XXX
     # addresses, whereas POST requests are from 192.16.3.XXX addresses. Three users
     # are represented in the sample requests.

     REQUESTS = [
         Request('GET', '192.168.2.20', 'jim'),
         Request('POST', '192.168.3.20', 'fred'),
         Request('GET', '192.168.2.21', 'sheila'),
         Request('POST', '192.168.3.21', 'jim'),
         Request('GET', '192.168.2.22', 'fred'),
         Request('POST', '192.168.3.22', 'sheila'),
     ]

     # Note that the format string includes references to request context information
     # such as HTTP method, client IP and username

     formatter = logging.Formatter('%(threadName)-11s %(appName)s %(name)-9s %(user)-6s %(ip)s %(method)-4s %(message)s')

     # Create our context variables. These will be filled at the start of request
     # processing, and used in the logging that happens during that processing

     ctx_request = ContextVar('request')
     ctx_appname = ContextVar('appname')

     class InjectingFilter(logging.Filter):
         """
         A filter which injects context-specific information into logs and ensures
         that only information for a specific webapp is included in its log
         """
         def __init__(self, app):
             self.app = app

         def filter(self, record):
             request = ctx_request.get()
             record.method = request.method
             record.ip = request.ip
             record.user = request.user
             record.appName = appName = ctx_appname.get()
             return appName == self.app.name

     class WebApp:
         """
         A dummy web application class which has its own handler and filter for a
         webapp-specific log.
         """
         def __init__(self, name):
             self.name = name
             handler = logging.FileHandler(name + '.log', 'w')
             f = InjectingFilter(self)
             handler.setFormatter(formatter)
             handler.addFilter(f)
             root.addHandler(handler)
             self.num_requests = 0

         def process_request(self, request):
             """
             This is the dummy method for processing a request. It's called on a
             different thread for every request. We store the context information into
             the context vars before doing anything else.
             """
             ctx_request.set(request)
             ctx_appname.set(self.name)
             self.num_requests += 1
             logger.debug('Request processing started')
             webapplib.useful()
             logger.debug('Request processing finished')

     def main():
         fn = os.path.splitext(os.path.basename(__file__))[0]
         adhf = argparse.ArgumentDefaultsHelpFormatter
         ap = argparse.ArgumentParser(formatter_class=adhf, prog=fn,
                                      description='Simulate a couple of web '
                                                  'applications handling some '
                                                  'requests, showing how request '
                                                  'context can be used to '
                                                  'populate logs')
         aa = ap.add_argument
         aa('--count', '-c', type=int, default=100, help='How many requests to simulate')
         options = ap.parse_args()

         # Create the dummy webapps and put them in a list which we can use to select
         # from randomly
         app1 = WebApp('app1')
         app2 = WebApp('app2')
         apps = [app1, app2]
         threads = []
         # Add a common handler which will capture all events
         handler = logging.FileHandler('app.log', 'w')
         handler.setFormatter(formatter)
         root.addHandler(handler)

         # Generate calls to process requests
         for i in range(options.count):
             try:
                 # Pick an app at random and a request for it to process
                 app = choice(apps)
                 request = choice(REQUESTS)
                 # Process the request in its own thread
                 t = threading.Thread(target=app.process_request, args=(request,))
                 threads.append(t)
                 t.start()
             except KeyboardInterrupt:
                 break

         # Wait for the threads to terminate
         for t in threads:
             t.join()

         for app in apps:
             print('%s processed %s requests' % (app.name, app.num_requests))

     if __name__ == '__main__':
         main()

If you run the above, you should find that roughly half the requests go
into ‘app1.log’ and the rest into ‘app2.log’, and the all the requests
are logged to ‘app.log’.  Each webapp-specific log will contain only log
entries for only that webapp, and the request information will be
displayed consistently in the log (i.e.  the information in each dummy
request will always appear together in a log line).  This is illustrated
by the following shell output:

     ~/logging-contextual-webapp$ python main.py
     app1 processed 51 requests
     app2 processed 49 requests
     ~/logging-contextual-webapp$ wc -l *.log
       153 app1.log
       147 app2.log
       300 app.log
       600 total
     ~/logging-contextual-webapp$ head -3 app1.log
     Thread-3 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
     Thread-3 (process_request) app1 webapplib jim    192.168.3.21 POST Hello from webapplib!
     Thread-5 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
     ~/logging-contextual-webapp$ head -3 app2.log
     Thread-1 (process_request) app2 __main__  sheila 192.168.2.21 GET  Request processing started
     Thread-1 (process_request) app2 webapplib sheila 192.168.2.21 GET  Hello from webapplib!
     Thread-2 (process_request) app2 __main__  jim    192.168.2.20 GET  Request processing started
     ~/logging-contextual-webapp$ head app.log
     Thread-1 (process_request) app2 __main__  sheila 192.168.2.21 GET  Request processing started
     Thread-1 (process_request) app2 webapplib sheila 192.168.2.21 GET  Hello from webapplib!
     Thread-2 (process_request) app2 __main__  jim    192.168.2.20 GET  Request processing started
     Thread-3 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
     Thread-2 (process_request) app2 webapplib jim    192.168.2.20 GET  Hello from webapplib!
     Thread-3 (process_request) app1 webapplib jim    192.168.3.21 POST Hello from webapplib!
     Thread-4 (process_request) app2 __main__  fred   192.168.2.22 GET  Request processing started
     Thread-5 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
     Thread-4 (process_request) app2 webapplib fred   192.168.2.22 GET  Hello from webapplib!
     Thread-6 (process_request) app1 __main__  jim    192.168.3.21 POST Request processing started
     ~/logging-contextual-webapp$ grep app1 app1.log | wc -l
     153
     ~/logging-contextual-webapp$ grep app2 app2.log | wc -l
     147
     ~/logging-contextual-webapp$ grep app1 app.log | wc -l
     153
     ~/logging-contextual-webapp$ grep app2 app.log | wc -l
     147


File: python.info,  Node: Imparting contextual information in handlers,  Next: Logging to a single file from multiple processes,  Prev: Use of contextvars,  Up: Logging Cookbook

9.9.11 Imparting contextual information in handlers
---------------------------------------------------

Each *note Handler: 14e5. has its own chain of filters.  If you want to
add contextual information to a *note LogRecord: 1021. without leaking
it to other handlers, you can use a filter that returns a new
‘LogRecord’ instead of modifying it in-place, as shown in the following
script:

     import copy
     import logging

     def filter(record: logging.LogRecord):
         record = copy.copy(record)
         record.user = 'jim'
         return record

     if __name__ == '__main__':
         logger = logging.getLogger()
         logger.setLevel(logging.INFO)
         handler = logging.StreamHandler()
         formatter = logging.Formatter('%(message)s from %(user)-8s')
         handler.setFormatter(formatter)
         handler.addFilter(filter)
         logger.addHandler(handler)

         logger.info('A log message')


File: python.info,  Node: Logging to a single file from multiple processes,  Next: Using file rotation,  Prev: Imparting contextual information in handlers,  Up: Logging Cookbook

9.9.12 Logging to a single file from multiple processes
-------------------------------------------------------

Although logging is thread-safe, and logging to a single file from
multiple threads in a single process 'is' supported, logging to a single
file from 'multiple processes' is 'not' supported, because there is no
standard way to serialize access to a single file across multiple
processes in Python.  If you need to log to a single file from multiple
processes, one way of doing this is to have all the processes log to a
*note SocketHandler: f9b, and have a separate process which implements a
socket server which reads from the socket and logs to file.  (If you
prefer, you can dedicate one thread in one of the existing processes to
perform this function.)  *note This section: 53ea. documents this
approach in more detail and includes a working socket receiver which can
be used as a starting point for you to adapt in your own applications.

You could also write your own handler which uses the *note Lock: 16a2.
class from the *note multiprocessing: 94. module to serialize access to
the file from your processes.  The stdlib *note FileHandler: 19f9. and
subclasses do not make use of ‘multiprocessing’.

Alternatively, you can use a ‘Queue’ and a *note QueueHandler: 1907. to
send all logging events to one of the processes in your multi-process
application.  The following example script demonstrates how you can do
this; in the example a separate listener process listens for events sent
by other processes and logs them according to its own logging
configuration.  Although the example only demonstrates one way of doing
it (for example, you may want to use a listener thread rather than a
separate listener process – the implementation would be analogous) it
does allow for completely different logging configurations for the
listener and the other processes in your application, and can be used as
the basis for code meeting your own specific requirements:

     # You'll need these imports in your own code
     import logging
     import logging.handlers
     import multiprocessing

     # Next two import lines for this demo only
     from random import choice, random
     import time

     #
     # Because you'll want to define the logging configurations for listener and workers, the
     # listener and worker process functions take a configurer parameter which is a callable
     # for configuring logging for that process. These functions are also passed the queue,
     # which they use for communication.
     #
     # In practice, you can configure the listener however you want, but note that in this
     # simple example, the listener does not apply level or filter logic to received records.
     # In practice, you would probably want to do this logic in the worker processes, to avoid
     # sending events which would be filtered out between processes.
     #
     # The size of the rotated files is made small so you can see the results easily.
     def listener_configurer():
         root = logging.getLogger()
         h = logging.handlers.RotatingFileHandler('mptest.log', 'a', 300, 10)
         f = logging.Formatter('%(asctime)s %(processName)-10s %(name)s %(levelname)-8s %(message)s')
         h.setFormatter(f)
         root.addHandler(h)

     # This is the listener process top-level loop: wait for logging events
     # (LogRecords)on the queue and handle them, quit when you get a None for a
     # LogRecord.
     def listener_process(queue, configurer):
         configurer()
         while True:
             try:
                 record = queue.get()
                 if record is None:  # We send this as a sentinel to tell the listener to quit.
                     break
                 logger = logging.getLogger(record.name)
                 logger.handle(record)  # No level or filter logic applied - just do it!
             except Exception:
                 import sys, traceback
                 print('Whoops! Problem:', file=sys.stderr)
                 traceback.print_exc(file=sys.stderr)

     # Arrays used for random selections in this demo

     LEVELS = [logging.DEBUG, logging.INFO, logging.WARNING,
               logging.ERROR, logging.CRITICAL]

     LOGGERS = ['a.b.c', 'd.e.f']

     MESSAGES = [
         'Random message #1',
         'Random message #2',
         'Random message #3',
     ]

     # The worker configuration is done at the start of the worker process run.
     # Note that on Windows you can't rely on fork semantics, so each process
     # will run the logging configuration code when it starts.
     def worker_configurer(queue):
         h = logging.handlers.QueueHandler(queue)  # Just the one handler needed
         root = logging.getLogger()
         root.addHandler(h)
         # send all messages, for demo; no other level or filter logic applied.
         root.setLevel(logging.DEBUG)

     # This is the worker process top-level loop, which just logs ten events with
     # random intervening delays before terminating.
     # The print messages are just so you know it's doing something!
     def worker_process(queue, configurer):
         configurer(queue)
         name = multiprocessing.current_process().name
         print('Worker started: %s' % name)
         for i in range(10):
             time.sleep(random())
             logger = logging.getLogger(choice(LOGGERS))
             level = choice(LEVELS)
             message = choice(MESSAGES)
             logger.log(level, message)
         print('Worker finished: %s' % name)

     # Here's where the demo gets orchestrated. Create the queue, create and start
     # the listener, create ten workers and start them, wait for them to finish,
     # then send a None to the queue to tell the listener to finish.
     def main():
         queue = multiprocessing.Queue(-1)
         listener = multiprocessing.Process(target=listener_process,
                                            args=(queue, listener_configurer))
         listener.start()
         workers = []
         for i in range(10):
             worker = multiprocessing.Process(target=worker_process,
                                              args=(queue, worker_configurer))
             workers.append(worker)
             worker.start()
         for w in workers:
             w.join()
         queue.put_nowait(None)
         listener.join()

     if __name__ == '__main__':
         main()

A variant of the above script keeps the logging in the main process, in
a separate thread:

     import logging
     import logging.config
     import logging.handlers
     from multiprocessing import Process, Queue
     import random
     import threading
     import time

     def logger_thread(q):
         while True:
             record = q.get()
             if record is None:
                 break
             logger = logging.getLogger(record.name)
             logger.handle(record)


     def worker_process(q):
         qh = logging.handlers.QueueHandler(q)
         root = logging.getLogger()
         root.setLevel(logging.DEBUG)
         root.addHandler(qh)
         levels = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
                   logging.CRITICAL]
         loggers = ['foo', 'foo.bar', 'foo.bar.baz',
                    'spam', 'spam.ham', 'spam.ham.eggs']
         for i in range(100):
             lvl = random.choice(levels)
             logger = logging.getLogger(random.choice(loggers))
             logger.log(lvl, 'Message no. %d', i)

     if __name__ == '__main__':
         q = Queue()
         d = {
             'version': 1,
             'formatters': {
                 'detailed': {
                     'class': 'logging.Formatter',
                     'format': '%(asctime)s %(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
                 }
             },
             'handlers': {
                 'console': {
                     'class': 'logging.StreamHandler',
                     'level': 'INFO',
                 },
                 'file': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog.log',
                     'mode': 'w',
                     'formatter': 'detailed',
                 },
                 'foofile': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog-foo.log',
                     'mode': 'w',
                     'formatter': 'detailed',
                 },
                 'errors': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog-errors.log',
                     'mode': 'w',
                     'level': 'ERROR',
                     'formatter': 'detailed',
                 },
             },
             'loggers': {
                 'foo': {
                     'handlers': ['foofile']
                 }
             },
             'root': {
                 'level': 'DEBUG',
                 'handlers': ['console', 'file', 'errors']
             },
         }
         workers = []
         for i in range(5):
             wp = Process(target=worker_process, name='worker %d' % (i + 1), args=(q,))
             workers.append(wp)
             wp.start()
         logging.config.dictConfig(d)
         lp = threading.Thread(target=logger_thread, args=(q,))
         lp.start()
         # At this point, the main process could do some useful work of its own
         # Once it's done that, it can wait for the workers to terminate...
         for wp in workers:
             wp.join()
         # And now tell the logging thread to finish up, too
         q.put(None)
         lp.join()

This variant shows how you can e.g.  apply configuration for particular
loggers - e.g.  the ‘foo’ logger has a special handler which stores all
events in the ‘foo’ subsystem in a file ‘mplog-foo.log’.  This will be
used by the logging machinery in the main process (even though the
logging events are generated in the worker processes) to direct the
messages to the appropriate destinations.

* Menu:

* Using concurrent.futures.ProcessPoolExecutor: Using concurrent futures ProcessPoolExecutor.
* Deploying web applications using Gunicorn and uWSGI::


File: python.info,  Node: Using concurrent futures ProcessPoolExecutor,  Next: Deploying web applications using Gunicorn and uWSGI,  Up: Logging to a single file from multiple processes

9.9.12.1 Using concurrent.futures.ProcessPoolExecutor
.....................................................

If you want to use *note concurrent.futures.ProcessPoolExecutor: 8f7. to
start your worker processes, you need to create the queue slightly
differently.  Instead of

     queue = multiprocessing.Queue(-1)

you should use

     queue = multiprocessing.Manager().Queue(-1)  # also works with the examples above

and you can then replace the worker creation from this:

     workers = []
     for i in range(10):
         worker = multiprocessing.Process(target=worker_process,
                                          args=(queue, worker_configurer))
         workers.append(worker)
         worker.start()
     for w in workers:
         w.join()

to this (remembering to first import *note concurrent.futures: 21.):

     with concurrent.futures.ProcessPoolExecutor(max_workers=10) as executor:
         for i in range(10):
             executor.submit(worker_process, queue, worker_configurer)


File: python.info,  Node: Deploying web applications using Gunicorn and uWSGI,  Prev: Using concurrent futures ProcessPoolExecutor,  Up: Logging to a single file from multiple processes

9.9.12.2 Deploying web applications using Gunicorn and uWSGI
............................................................

When deploying web applications using Gunicorn(1) or uWSGI(2) (or
similar), multiple worker processes are created to handle client
requests.  In such environments, avoid creating file-based handlers
directly in your web application.  Instead, use a *note SocketHandler:
f9b. to log from the web application to a listener in a separate
process.  This can be set up using a process management tool such as
Supervisor - see *note Running a logging socket listener in production:
53ec. for more details.

   ---------- Footnotes ----------

   (1) https://gunicorn.org/

   (2) https://uwsgi-docs.readthedocs.io/en/latest/


File: python.info,  Node: Using file rotation,  Next: Use of alternative formatting styles,  Prev: Logging to a single file from multiple processes,  Up: Logging Cookbook

9.9.13 Using file rotation
--------------------------

Sometimes you want to let a log file grow to a certain size, then open a
new file and log to that.  You may want to keep a certain number of
these files, and when that many files have been created, rotate the
files so that the number of files and the size of the files both remain
bounded.  For this usage pattern, the logging package provides a *note
RotatingFileHandler: 16e0.:

     import glob
     import logging
     import logging.handlers

     LOG_FILENAME = 'logging_rotatingfile_example.out'

     # Set up a specific logger with our desired output level
     my_logger = logging.getLogger('MyLogger')
     my_logger.setLevel(logging.DEBUG)

     # Add the log message handler to the logger
     handler = logging.handlers.RotatingFileHandler(
                   LOG_FILENAME, maxBytes=20, backupCount=5)

     my_logger.addHandler(handler)

     # Log some messages
     for i in range(20):
         my_logger.debug('i = %d' % i)

     # See what files are created
     logfiles = glob.glob('%s*' % LOG_FILENAME)

     for filename in logfiles:
         print(filename)

The result should be 6 separate files, each with part of the log history
for the application:

     logging_rotatingfile_example.out
     logging_rotatingfile_example.out.1
     logging_rotatingfile_example.out.2
     logging_rotatingfile_example.out.3
     logging_rotatingfile_example.out.4
     logging_rotatingfile_example.out.5

The most current file is always ‘logging_rotatingfile_example.out’, and
each time it reaches the size limit it is renamed with the suffix ‘.1’.
Each of the existing backup files is renamed to increment the suffix
(‘.1’ becomes ‘.2’, etc.)  and the ‘.6’ file is erased.

Obviously this example sets the log length much too small as an extreme
example.  You would want to set 'maxBytes' to an appropriate value.


File: python.info,  Node: Use of alternative formatting styles,  Next: Customizing LogRecord,  Prev: Using file rotation,  Up: Logging Cookbook

9.9.14 Use of alternative formatting styles
-------------------------------------------

When logging was added to the Python standard library, the only way of
formatting messages with variable content was to use the %-formatting
method.  Since then, Python has gained two new formatting approaches:
*note string.Template: 68a. (added in Python 2.4) and *note
str.format(): 624. (added in Python 2.6).

Logging (as of 3.2) provides improved support for these two additional
formatting styles.  The *note Formatter: 14e6. class been enhanced to
take an additional, optional keyword parameter named ‘style’.  This
defaults to ‘'%'’, but other possible values are ‘'{'’ and ‘'$'’, which
correspond to the other two formatting styles.  Backwards compatibility
is maintained by default (as you would expect), but by explicitly
specifying a style parameter, you get the ability to specify format
strings which work with *note str.format(): 624. or *note
string.Template: 68a.  Here’s an example console session to show the
possibilities:

     >>> import logging
     >>> root = logging.getLogger()
     >>> root.setLevel(logging.DEBUG)
     >>> handler = logging.StreamHandler()
     >>> bf = logging.Formatter('{asctime} {name} {levelname:8s} {message}',
     ...                        style='{')
     >>> handler.setFormatter(bf)
     >>> root.addHandler(handler)
     >>> logger = logging.getLogger('foo.bar')
     >>> logger.debug('This is a DEBUG message')
     2010-10-28 15:11:55,341 foo.bar DEBUG    This is a DEBUG message
     >>> logger.critical('This is a CRITICAL message')
     2010-10-28 15:12:11,526 foo.bar CRITICAL This is a CRITICAL message
     >>> df = logging.Formatter('$asctime $name ${levelname} $message',
     ...                        style='$')
     >>> handler.setFormatter(df)
     >>> logger.debug('This is a DEBUG message')
     2010-10-28 15:13:06,924 foo.bar DEBUG This is a DEBUG message
     >>> logger.critical('This is a CRITICAL message')
     2010-10-28 15:13:11,494 foo.bar CRITICAL This is a CRITICAL message
     >>>

Note that the formatting of logging messages for final output to logs is
completely independent of how an individual logging message is
constructed.  That can still use %-formatting, as shown here:

     >>> logger.error('This is an%s %s %s', 'other,', 'ERROR,', 'message')
     2010-10-28 15:19:29,833 foo.bar ERROR This is another, ERROR, message
     >>>

Logging calls (‘logger.debug()’, ‘logger.info()’ etc.)  only take
positional parameters for the actual logging message itself, with
keyword parameters used only for determining options for how to handle
the actual logging call (e.g.  the ‘exc_info’ keyword parameter to
indicate that traceback information should be logged, or the ‘extra’
keyword parameter to indicate additional contextual information to be
added to the log).  So you cannot directly make logging calls using
*note str.format(): 624. or *note string.Template: 68a. syntax, because
internally the logging package uses %-formatting to merge the format
string and the variable arguments.  There would be no changing this
while preserving backward compatibility, since all logging calls which
are out there in existing code will be using %-format strings.

There is, however, a way that you can use {}- and $- formatting to
construct your individual log messages.  Recall that for a message you
can use an arbitrary object as a message format string, and that the
logging package will call ‘str()’ on that object to get the actual
format string.  Consider the following two classes:

     class BraceMessage:
         def __init__(self, fmt, /, *args, **kwargs):
             self.fmt = fmt
             self.args = args
             self.kwargs = kwargs

         def __str__(self):
             return self.fmt.format(*self.args, **self.kwargs)

     class DollarMessage:
         def __init__(self, fmt, /, **kwargs):
             self.fmt = fmt
             self.kwargs = kwargs

         def __str__(self):
             from string import Template
             return Template(self.fmt).substitute(**self.kwargs)

Either of these can be used in place of a format string, to allow {}- or
$-formatting to be used to build the actual “message” part which appears
in the formatted log output in place of “%(message)s” or “{message}” or
“$message”.  It’s a little unwieldy to use the class names whenever you
want to log something, but it’s quite palatable if you use an alias such
as __ (double underscore — not to be confused with _, the single
underscore used as a synonym/alias for *note gettext.gettext(): 14b8. or
its brethren).

The above classes are not included in Python, though they’re easy enough
to copy and paste into your own code.  They can be used as follows
(assuming that they’re declared in a module called ‘wherever’):

     >>> from wherever import BraceMessage as __
     >>> print(__('Message with {0} {name}', 2, name='placeholders'))
     Message with 2 placeholders
     >>> class Point: pass
     ...
     >>> p = Point()
     >>> p.x = 0.5
     >>> p.y = 0.5
     >>> print(__('Message with coordinates: ({point.x:.2f}, {point.y:.2f})',
     ...       point=p))
     Message with coordinates: (0.50, 0.50)
     >>> from wherever import DollarMessage as __
     >>> print(__('Message with $num $what', num=2, what='placeholders'))
     Message with 2 placeholders
     >>>

While the above examples use ‘print()’ to show how the formatting works,
you would of course use ‘logger.debug()’ or similar to actually log
using this approach.

One thing to note is that you pay no significant performance penalty
with this approach: the actual formatting happens not when you make the
logging call, but when (and if) the logged message is actually about to
be output to a log by a handler.  So the only slightly unusual thing
which might trip you up is that the parentheses go around the format
string and the arguments, not just the format string.  That’s because
the __ notation is just syntax sugar for a constructor call to one of
the ‘XXXMessage’ classes.

If you prefer, you can use a *note LoggerAdapter: 133e. to achieve a
similar effect to the above, as in the following example:

     import logging

     class Message:
         def __init__(self, fmt, args):
             self.fmt = fmt
             self.args = args

         def __str__(self):
             return self.fmt.format(*self.args)

     class StyleAdapter(logging.LoggerAdapter):
         def log(self, level, msg, /, *args, stacklevel=1, **kwargs):
             if self.isEnabledFor(level):
                 msg, kwargs = self.process(msg, kwargs)
                 self.logger.log(level, Message(msg, args), **kwargs,
                                 stacklevel=stacklevel+1)

     logger = StyleAdapter(logging.getLogger(__name__))

     def main():
         logger.debug('Hello, {}', 'world!')

     if __name__ == '__main__':
         logging.basicConfig(level=logging.DEBUG)
         main()

The above script should log the message ‘Hello, world!’ when run with
Python 3.8 or later.


File: python.info,  Node: Customizing LogRecord,  Next: Subclassing QueueHandler and QueueListener- a ZeroMQ example,  Prev: Use of alternative formatting styles,  Up: Logging Cookbook

9.9.15 Customizing ‘LogRecord’
------------------------------

Every logging event is represented by a *note LogRecord: 1021. instance.
When an event is logged and not filtered out by a logger’s level, a
‘LogRecord’ is created, populated with information about the event and
then passed to the handlers for that logger (and its ancestors, up to
and including the logger where further propagation up the hierarchy is
disabled).  Before Python 3.2, there were only two places where this
creation was done:

   * *note Logger.makeRecord(): 2e61, which is called in the normal
     process of logging an event.  This invoked *note LogRecord: 1021.
     directly to create an instance.

   * *note makeLogRecord(): 2e87, which is called with a dictionary
     containing attributes to be added to the LogRecord.  This is
     typically invoked when a suitable dictionary has been received over
     the network (e.g.  in pickle form via a *note SocketHandler: f9b,
     or in JSON form via an *note HTTPHandler: e5e.).

This has usually meant that if you need to do anything special with a
*note LogRecord: 1021, you’ve had to do one of the following.

   * Create your own *note Logger: b6a. subclass, which overrides *note
     Logger.makeRecord(): 2e61, and set it using *note setLoggerClass():
     2e96. before any loggers that you care about are instantiated.

   * Add a *note Filter: 1240. to a logger or handler, which does the
     necessary special manipulation you need when its *note filter():
     2e82. method is called.

The first approach would be a little unwieldy in the scenario where
(say) several different libraries wanted to do different things.  Each
would attempt to set its own *note Logger: b6a. subclass, and the one
which did this last would win.

The second approach works reasonably well for many cases, but does not
allow you to e.g.  use a specialized subclass of *note LogRecord: 1021.
Library developers can set a suitable filter on their loggers, but they
would have to remember to do this every time they introduced a new
logger (which they would do simply by adding new packages or modules and
doing

     logger = logging.getLogger(__name__)

at module level).  It’s probably one too many things to think about.
Developers could also add the filter to a *note NullHandler: 12cb.
attached to their top-level logger, but this would not be invoked if an
application developer attached a handler to a lower-level library logger
— so output from that handler would not reflect the intentions of the
library developer.

In Python 3.2 and later, *note LogRecord: 1021. creation is done through
a factory, which you can specify.  The factory is just a callable you
can set with *note setLogRecordFactory(): 2e8b, and interrogate with
*note getLogRecordFactory(): 2e8a.  The factory is invoked with the same
signature as the ‘LogRecord’ constructor, as *note LogRecord: 1021. is
the default setting for the factory.

This approach allows a custom factory to control all aspects of
LogRecord creation.  For example, you could return a subclass, or just
add some additional attributes to the record once created, using a
pattern similar to this:

     old_factory = logging.getLogRecordFactory()

     def record_factory(*args, **kwargs):
         record = old_factory(*args, **kwargs)
         record.custom_attribute = 0xdecafbad
         return record

     logging.setLogRecordFactory(record_factory)

This pattern allows different libraries to chain factories together, and
as long as they don’t overwrite each other’s attributes or
unintentionally overwrite the attributes provided as standard, there
should be no surprises.  However, it should be borne in mind that each
link in the chain adds run-time overhead to all logging operations, and
the technique should only be used when the use of a *note Filter: 1240.
does not provide the desired result.


File: python.info,  Node: Subclassing QueueHandler and QueueListener- a ZeroMQ example,  Next: Subclassing QueueHandler and QueueListener- a pynng example,  Prev: Customizing LogRecord,  Up: Logging Cookbook

9.9.16 Subclassing QueueHandler and QueueListener- a ZeroMQ example
-------------------------------------------------------------------

* Menu:

* Subclass QueueHandler::
* Subclass QueueListener::


File: python.info,  Node: Subclass QueueHandler,  Next: Subclass QueueListener,  Up: Subclassing QueueHandler and QueueListener- a ZeroMQ example

9.9.16.1 Subclass ‘QueueHandler’
................................

You can use a *note QueueHandler: 1907. subclass to send messages to
other kinds of queues, for example a ZeroMQ ‘publish’ socket.  In the
example below,the socket is created separately and passed to the handler
(as its ‘queue’):

     import zmq   # using pyzmq, the Python binding for ZeroMQ
     import json  # for serializing records portably

     ctx = zmq.Context()
     sock = zmq.Socket(ctx, zmq.PUB)  # or zmq.PUSH, or other suitable value
     sock.bind('tcp://*:5556')        # or wherever

     class ZeroMQSocketHandler(QueueHandler):
         def enqueue(self, record):
             self.queue.send_json(record.__dict__)


     handler = ZeroMQSocketHandler(sock)

Of course there are other ways of organizing this, for example passing
in the data needed by the handler to create the socket:

     class ZeroMQSocketHandler(QueueHandler):
         def __init__(self, uri, socktype=zmq.PUB, ctx=None):
             self.ctx = ctx or zmq.Context()
             socket = zmq.Socket(self.ctx, socktype)
             socket.bind(uri)
             super().__init__(socket)

         def enqueue(self, record):
             self.queue.send_json(record.__dict__)

         def close(self):
             self.queue.close()


File: python.info,  Node: Subclass QueueListener,  Prev: Subclass QueueHandler,  Up: Subclassing QueueHandler and QueueListener- a ZeroMQ example

9.9.16.2 Subclass ‘QueueListener’
.................................

You can also subclass *note QueueListener: e5f. to get messages from
other kinds of queues, for example a ZeroMQ ‘subscribe’ socket.  Here’s
an example:

     class ZeroMQSocketListener(QueueListener):
         def __init__(self, uri, /, *handlers, **kwargs):
             self.ctx = kwargs.get('ctx') or zmq.Context()
             socket = zmq.Socket(self.ctx, zmq.SUB)
             socket.setsockopt_string(zmq.SUBSCRIBE, '')  # subscribe to everything
             socket.connect(uri)
             super().__init__(socket, *handlers, **kwargs)

         def dequeue(self):
             msg = self.queue.recv_json()
             return logging.makeLogRecord(msg)


File: python.info,  Node: Subclassing QueueHandler and QueueListener- a pynng example,  Next: An example dictionary-based configuration,  Prev: Subclassing QueueHandler and QueueListener- a ZeroMQ example,  Up: Logging Cookbook

9.9.17 Subclassing QueueHandler and QueueListener- a ‘pynng’ example
--------------------------------------------------------------------

In a similar way to the above section, we can implement a listener and
handler using pynng(1), which is a Python binding to NNG(2), billed as a
spiritual successor to ZeroMQ. The following snippets illustrate – you
can test them in an environment which has ‘pynng’ installed.  Just for
variety, we present the listener first.

* Menu:

* Subclass QueueListener: Subclass QueueListener<2>.
* Subclass QueueHandler: Subclass QueueHandler<2>.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/pynng/

   (2) https://nng.nanomsg.org/


File: python.info,  Node: Subclass QueueListener<2>,  Next: Subclass QueueHandler<2>,  Up: Subclassing QueueHandler and QueueListener- a pynng example

9.9.17.1 Subclass ‘QueueListener’
.................................

     # listener.py
     import json
     import logging
     import logging.handlers

     import pynng

     DEFAULT_ADDR = "tcp://localhost:13232"

     interrupted = False

     class NNGSocketListener(logging.handlers.QueueListener):

         def __init__(self, uri, /, *handlers, **kwargs):
             # Have a timeout for interruptability, and open a
             # subscriber socket
             socket = pynng.Sub0(listen=uri, recv_timeout=500)
             # The b'' subscription matches all topics
             topics = kwargs.pop('topics', None) or b''
             socket.subscribe(topics)
             # We treat the socket as a queue
             super().__init__(socket, *handlers, **kwargs)

         def dequeue(self, block):
             data = None
             # Keep looping while not interrupted and no data received over the
             # socket
             while not interrupted:
                 try:
                     data = self.queue.recv(block=block)
                     break
                 except pynng.Timeout:
                     pass
                 except pynng.Closed:  # sometimes happens when you hit Ctrl-C
                     break
             if data is None:
                 return None
             # Get the logging event sent from a publisher
             event = json.loads(data.decode('utf-8'))
             return logging.makeLogRecord(event)

         def enqueue_sentinel(self):
             # Not used in this implementation, as the socket isn't really a
             # queue
             pass

     logging.getLogger('pynng').propagate = False
     listener = NNGSocketListener(DEFAULT_ADDR, logging.StreamHandler(), topics=b'')
     listener.start()
     print('Press Ctrl-C to stop.')
     try:
         while True:
             pass
     except KeyboardInterrupt:
         interrupted = True
     finally:
         listener.stop()


File: python.info,  Node: Subclass QueueHandler<2>,  Prev: Subclass QueueListener<2>,  Up: Subclassing QueueHandler and QueueListener- a pynng example

9.9.17.2 Subclass ‘QueueHandler’
................................

     # sender.py
     import json
     import logging
     import logging.handlers
     import time
     import random

     import pynng

     DEFAULT_ADDR = "tcp://localhost:13232"

     class NNGSocketHandler(logging.handlers.QueueHandler):

         def __init__(self, uri):
             socket = pynng.Pub0(dial=uri, send_timeout=500)
             super().__init__(socket)

         def enqueue(self, record):
             # Send the record as UTF-8 encoded JSON
             d = dict(record.__dict__)
             data = json.dumps(d)
             self.queue.send(data.encode('utf-8'))

         def close(self):
             self.queue.close()

     logging.getLogger('pynng').propagate = False
     handler = NNGSocketHandler(DEFAULT_ADDR)
     # Make sure the process ID is in the output
     logging.basicConfig(level=logging.DEBUG,
                         handlers=[logging.StreamHandler(), handler],
                         format='%(levelname)-8s %(name)10s %(process)6s %(message)s')
     levels = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
               logging.CRITICAL)
     logger_names = ('myapp', 'myapp.lib1', 'myapp.lib2')
     msgno = 1
     while True:
         # Just randomly select some loggers and levels and log away
         level = random.choice(levels)
         logger = logging.getLogger(random.choice(logger_names))
         logger.log(level, 'Message no. %5d' % msgno)
         msgno += 1
         delay = random.random() * 2 + 0.5
         time.sleep(delay)

You can run the above two snippets in separate command shells.  If we
run the listener in one shell and run the sender in two separate shells,
we should see something like the following.  In the first sender shell:

     $ python sender.py
     DEBUG         myapp    613 Message no.     1
     WARNING  myapp.lib2    613 Message no.     2
     CRITICAL myapp.lib2    613 Message no.     3
     WARNING  myapp.lib2    613 Message no.     4
     CRITICAL myapp.lib1    613 Message no.     5
     DEBUG         myapp    613 Message no.     6
     CRITICAL myapp.lib1    613 Message no.     7
     INFO     myapp.lib1    613 Message no.     8
     (and so on)

In the second sender shell:

     $ python sender.py
     INFO     myapp.lib2    657 Message no.     1
     CRITICAL myapp.lib2    657 Message no.     2
     CRITICAL      myapp    657 Message no.     3
     CRITICAL myapp.lib1    657 Message no.     4
     INFO     myapp.lib1    657 Message no.     5
     WARNING  myapp.lib2    657 Message no.     6
     CRITICAL      myapp    657 Message no.     7
     DEBUG    myapp.lib1    657 Message no.     8
     (and so on)

In the listener shell:

     $ python listener.py
     Press Ctrl-C to stop.
     DEBUG         myapp    613 Message no.     1
     WARNING  myapp.lib2    613 Message no.     2
     INFO     myapp.lib2    657 Message no.     1
     CRITICAL myapp.lib2    613 Message no.     3
     CRITICAL myapp.lib2    657 Message no.     2
     CRITICAL      myapp    657 Message no.     3
     WARNING  myapp.lib2    613 Message no.     4
     CRITICAL myapp.lib1    613 Message no.     5
     CRITICAL myapp.lib1    657 Message no.     4
     INFO     myapp.lib1    657 Message no.     5
     DEBUG         myapp    613 Message no.     6
     WARNING  myapp.lib2    657 Message no.     6
     CRITICAL      myapp    657 Message no.     7
     CRITICAL myapp.lib1    613 Message no.     7
     INFO     myapp.lib1    613 Message no.     8
     DEBUG    myapp.lib1    657 Message no.     8
     (and so on)

As you can see, the logging from the two sender processes is interleaved
in the listener’s output.


File: python.info,  Node: An example dictionary-based configuration,  Next: Using a rotator and namer to customize log rotation processing,  Prev: Subclassing QueueHandler and QueueListener- a pynng example,  Up: Logging Cookbook

9.9.18 An example dictionary-based configuration
------------------------------------------------

Below is an example of a logging configuration dictionary - it’s taken
from the documentation on the Django project(1).  This dictionary is
passed to *note dictConfig(): 11f4. to put the configuration into
effect:

     LOGGING = {
         'version': 1,
         'disable_existing_loggers': False,
         'formatters': {
             'verbose': {
                 'format': '{levelname} {asctime} {module} {process:d} {thread:d} {message}',
                 'style': '{',
             },
             'simple': {
                 'format': '{levelname} {message}',
                 'style': '{',
             },
         },
         'filters': {
             'special': {
                 '()': 'project.logging.SpecialFilter',
                 'foo': 'bar',
             },
         },
         'handlers': {
             'console': {
                 'level': 'INFO',
                 'class': 'logging.StreamHandler',
                 'formatter': 'simple',
             },
             'mail_admins': {
                 'level': 'ERROR',
                 'class': 'django.utils.log.AdminEmailHandler',
                 'filters': ['special']
             }
         },
         'loggers': {
             'django': {
                 'handlers': ['console'],
                 'propagate': True,
             },
             'django.request': {
                 'handlers': ['mail_admins'],
                 'level': 'ERROR',
                 'propagate': False,
             },
             'myproject.custom': {
                 'handlers': ['console', 'mail_admins'],
                 'level': 'INFO',
                 'filters': ['special']
             }
         }
     }

For more information about this configuration, you can see the relevant
section(2) of the Django documentation.

   ---------- Footnotes ----------

   (1) 
https://docs.djangoproject.com/en/stable/topics/logging/#configuring-logging

   (2) 
https://docs.djangoproject.com/en/stable/topics/logging/#configuring-logging


File: python.info,  Node: Using a rotator and namer to customize log rotation processing,  Next: A more elaborate multiprocessing example,  Prev: An example dictionary-based configuration,  Up: Logging Cookbook

9.9.19 Using a rotator and namer to customize log rotation processing
---------------------------------------------------------------------

An example of how you can define a namer and rotator is given in the
following runnable script, which shows gzip compression of the log file:

     import gzip
     import logging
     import logging.handlers
     import os
     import shutil

     def namer(name):
         return name + ".gz"

     def rotator(source, dest):
         with open(source, 'rb') as f_in:
             with gzip.open(dest, 'wb') as f_out:
                 shutil.copyfileobj(f_in, f_out)
         os.remove(source)


     rh = logging.handlers.RotatingFileHandler('rotated.log', maxBytes=128, backupCount=5)
     rh.rotator = rotator
     rh.namer = namer

     root = logging.getLogger()
     root.setLevel(logging.INFO)
     root.addHandler(rh)
     f = logging.Formatter('%(asctime)s %(message)s')
     rh.setFormatter(f)
     for i in range(1000):
         root.info(f'Message no. {i + 1}')

After running this, you will see six new files, five of which are
compressed:

     $ ls rotated.log*
     rotated.log       rotated.log.2.gz  rotated.log.4.gz
     rotated.log.1.gz  rotated.log.3.gz  rotated.log.5.gz
     $ zcat rotated.log.1.gz
     2023-01-20 02:28:17,767 Message no. 996
     2023-01-20 02:28:17,767 Message no. 997
     2023-01-20 02:28:17,767 Message no. 998


File: python.info,  Node: A more elaborate multiprocessing example,  Next: Inserting a BOM into messages sent to a SysLogHandler,  Prev: Using a rotator and namer to customize log rotation processing,  Up: Logging Cookbook

9.9.20 A more elaborate multiprocessing example
-----------------------------------------------

The following working example shows how logging can be used with
multiprocessing using configuration files.  The configurations are
fairly simple, but serve to illustrate how more complex ones could be
implemented in a real multiprocessing scenario.

In the example, the main process spawns a listener process and some
worker processes.  Each of the main process, the listener and the
workers have three separate configurations (the workers all share the
same configuration).  We can see logging in the main process, how the
workers log to a QueueHandler and how the listener implements a
QueueListener and a more complex logging configuration, and arranges to
dispatch events received via the queue to the handlers specified in the
configuration.  Note that these configurations are purely illustrative,
but you should be able to adapt this example to your own scenario.

Here’s the script - the docstrings and the comments hopefully explain
how it works:

     import logging
     import logging.config
     import logging.handlers
     from multiprocessing import Process, Queue, Event, current_process
     import os
     import random
     import time

     class MyHandler:
         """
         A simple handler for logging events. It runs in the listener process and
         dispatches events to loggers based on the name in the received record,
         which then get dispatched, by the logging system, to the handlers
         configured for those loggers.
         """

         def handle(self, record):
             if record.name == "root":
                 logger = logging.getLogger()
             else:
                 logger = logging.getLogger(record.name)

             if logger.isEnabledFor(record.levelno):
                 # The process name is transformed just to show that it's the listener
                 # doing the logging to files and console
                 record.processName = '%s (for %s)' % (current_process().name, record.processName)
                 logger.handle(record)

     def listener_process(q, stop_event, config):
         """
         This could be done in the main process, but is just done in a separate
         process for illustrative purposes.

         This initialises logging according to the specified configuration,
         starts the listener and waits for the main process to signal completion
         via the event. The listener is then stopped, and the process exits.
         """
         logging.config.dictConfig(config)
         listener = logging.handlers.QueueListener(q, MyHandler())
         listener.start()
         if os.name == 'posix':
             # On POSIX, the setup logger will have been configured in the
             # parent process, but should have been disabled following the
             # dictConfig call.
             # On Windows, since fork isn't used, the setup logger won't
             # exist in the child, so it would be created and the message
             # would appear - hence the "if posix" clause.
             logger = logging.getLogger('setup')
             logger.critical('Should not appear, because of disabled logger ...')
         stop_event.wait()
         listener.stop()

     def worker_process(config):
         """
         A number of these are spawned for the purpose of illustration. In
         practice, they could be a heterogeneous bunch of processes rather than
         ones which are identical to each other.

         This initialises logging according to the specified configuration,
         and logs a hundred messages with random levels to randomly selected
         loggers.

         A small sleep is added to allow other processes a chance to run. This
         is not strictly needed, but it mixes the output from the different
         processes a bit more than if it's left out.
         """
         logging.config.dictConfig(config)
         levels = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
                   logging.CRITICAL]
         loggers = ['foo', 'foo.bar', 'foo.bar.baz',
                    'spam', 'spam.ham', 'spam.ham.eggs']
         if os.name == 'posix':
             # On POSIX, the setup logger will have been configured in the
             # parent process, but should have been disabled following the
             # dictConfig call.
             # On Windows, since fork isn't used, the setup logger won't
             # exist in the child, so it would be created and the message
             # would appear - hence the "if posix" clause.
             logger = logging.getLogger('setup')
             logger.critical('Should not appear, because of disabled logger ...')
         for i in range(100):
             lvl = random.choice(levels)
             logger = logging.getLogger(random.choice(loggers))
             logger.log(lvl, 'Message no. %d', i)
             time.sleep(0.01)

     def main():
         q = Queue()
         # The main process gets a simple configuration which prints to the console.
         config_initial = {
             'version': 1,
             'handlers': {
                 'console': {
                     'class': 'logging.StreamHandler',
                     'level': 'INFO'
                 }
             },
             'root': {
                 'handlers': ['console'],
                 'level': 'DEBUG'
             }
         }
         # The worker process configuration is just a QueueHandler attached to the
         # root logger, which allows all messages to be sent to the queue.
         # We disable existing loggers to disable the "setup" logger used in the
         # parent process. This is needed on POSIX because the logger will
         # be there in the child following a fork().
         config_worker = {
             'version': 1,
             'disable_existing_loggers': True,
             'handlers': {
                 'queue': {
                     'class': 'logging.handlers.QueueHandler',
                     'queue': q
                 }
             },
             'root': {
                 'handlers': ['queue'],
                 'level': 'DEBUG'
             }
         }
         # The listener process configuration shows that the full flexibility of
         # logging configuration is available to dispatch events to handlers however
         # you want.
         # We disable existing loggers to disable the "setup" logger used in the
         # parent process. This is needed on POSIX because the logger will
         # be there in the child following a fork().
         config_listener = {
             'version': 1,
             'disable_existing_loggers': True,
             'formatters': {
                 'detailed': {
                     'class': 'logging.Formatter',
                     'format': '%(asctime)s %(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
                 },
                 'simple': {
                     'class': 'logging.Formatter',
                     'format': '%(name)-15s %(levelname)-8s %(processName)-10s %(message)s'
                 }
             },
             'handlers': {
                 'console': {
                     'class': 'logging.StreamHandler',
                     'formatter': 'simple',
                     'level': 'INFO'
                 },
                 'file': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog.log',
                     'mode': 'w',
                     'formatter': 'detailed'
                 },
                 'foofile': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog-foo.log',
                     'mode': 'w',
                     'formatter': 'detailed'
                 },
                 'errors': {
                     'class': 'logging.FileHandler',
                     'filename': 'mplog-errors.log',
                     'mode': 'w',
                     'formatter': 'detailed',
                     'level': 'ERROR'
                 }
             },
             'loggers': {
                 'foo': {
                     'handlers': ['foofile']
                 }
             },
             'root': {
                 'handlers': ['console', 'file', 'errors'],
                 'level': 'DEBUG'
             }
         }
         # Log some initial events, just to show that logging in the parent works
         # normally.
         logging.config.dictConfig(config_initial)
         logger = logging.getLogger('setup')
         logger.info('About to create workers ...')
         workers = []
         for i in range(5):
             wp = Process(target=worker_process, name='worker %d' % (i + 1),
                          args=(config_worker,))
             workers.append(wp)
             wp.start()
             logger.info('Started worker: %s', wp.name)
         logger.info('About to create listener ...')
         stop_event = Event()
         lp = Process(target=listener_process, name='listener',
                      args=(q, stop_event, config_listener))
         lp.start()
         logger.info('Started listener')
         # We now hang around for the workers to finish their work.
         for wp in workers:
             wp.join()
         # Workers all done, listening can now stop.
         # Logging in the parent still works normally.
         logger.info('Telling listener to stop ...')
         stop_event.set()
         lp.join()
         logger.info('All done.')

     if __name__ == '__main__':
         main()


File: python.info,  Node: Inserting a BOM into messages sent to a SysLogHandler,  Next: Implementing structured logging,  Prev: A more elaborate multiprocessing example,  Up: Logging Cookbook

9.9.21 Inserting a BOM into messages sent to a SysLogHandler
------------------------------------------------------------

RFC 5424(1) requires that a Unicode message be sent to a syslog daemon
as a set of bytes which have the following structure: an optional
pure-ASCII component, followed by a UTF-8 Byte Order Mark (BOM),
followed by Unicode encoded using UTF-8.  (See the relevant section of
the specification(2).)

In Python 3.1, code was added to *note SysLogHandler: 65f. to insert a
BOM into the message, but unfortunately, it was implemented incorrectly,
with the BOM appearing at the beginning of the message and hence not
allowing any pure-ASCII component to appear before it.

As this behaviour is broken, the incorrect BOM insertion code is being
removed from Python 3.2.4 and later.  However, it is not being replaced,
and if you want to produce RFC 5424(3)-compliant messages which include
a BOM, an optional pure-ASCII sequence before it and arbitrary Unicode
after it, encoded using UTF-8, then you need to do the following:

  1. Attach a *note Formatter: 14e6. instance to your *note
     SysLogHandler: 65f. instance, with a format string such as:

          'ASCII section\ufeffUnicode section'

     The Unicode code point U+FEFF, when encoded using UTF-8, will be
     encoded as a UTF-8 BOM – the byte-string ‘b'\xef\xbb\xbf'’.

  2. Replace the ASCII section with whatever placeholders you like, but
     make sure that the data that appears in there after substitution is
     always ASCII (that way, it will remain unchanged after UTF-8
     encoding).

  3. Replace the Unicode section with whatever placeholders you like; if
     the data which appears there after substitution contains characters
     outside the ASCII range, that’s fine – it will be encoded using
     UTF-8.

The formatted message 'will' be encoded using UTF-8 encoding by
‘SysLogHandler’.  If you follow the above rules, you should be able to
produce RFC 5424(4)-compliant messages.  If you don’t, logging may not
complain, but your messages will not be RFC 5424-compliant, and your
syslog daemon may complain.

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5424.html

   (2) https://datatracker.ietf.org/doc/html/rfc5424.html#section-6

   (3) https://datatracker.ietf.org/doc/html/rfc5424.html

   (4) https://datatracker.ietf.org/doc/html/rfc5424.html


File: python.info,  Node: Implementing structured logging,  Next: Customizing handlers with dictConfig,  Prev: Inserting a BOM into messages sent to a SysLogHandler,  Up: Logging Cookbook

9.9.22 Implementing structured logging
--------------------------------------

Although most logging messages are intended for reading by humans, and
thus not readily machine-parseable, there might be circumstances where
you want to output messages in a structured format which 'is' capable of
being parsed by a program (without needing complex regular expressions
to parse the log message).  This is straightforward to achieve using the
logging package.  There are a number of ways in which this could be
achieved, but the following is a simple approach which uses JSON to
serialise the event in a machine-parseable manner:

     import json
     import logging

     class StructuredMessage:
         def __init__(self, message, /, **kwargs):
             self.message = message
             self.kwargs = kwargs

         def __str__(self):
             return '%s >>> %s' % (self.message, json.dumps(self.kwargs))

     _ = StructuredMessage   # optional, to improve readability

     logging.basicConfig(level=logging.INFO, format='%(message)s')
     logging.info(_('message 1', foo='bar', bar='baz', num=123, fnum=123.456))

If the above script is run, it prints:

     message 1 >>> {"fnum": 123.456, "num": 123, "bar": "baz", "foo": "bar"}

Note that the order of items might be different according to the version
of Python used.

If you need more specialised processing, you can use a custom JSON
encoder, as in the following complete example:

     import json
     import logging


     class Encoder(json.JSONEncoder):
         def default(self, o):
             if isinstance(o, set):
                 return tuple(o)
             elif isinstance(o, str):
                 return o.encode('unicode_escape').decode('ascii')
             return super().default(o)

     class StructuredMessage:
         def __init__(self, message, /, **kwargs):
             self.message = message
             self.kwargs = kwargs

         def __str__(self):
             s = Encoder().encode(self.kwargs)
             return '%s >>> %s' % (self.message, s)

     _ = StructuredMessage   # optional, to improve readability

     def main():
         logging.basicConfig(level=logging.INFO, format='%(message)s')
         logging.info(_('message 1', set_value={1, 2, 3}, snowman='\u2603'))

     if __name__ == '__main__':
         main()

When the above script is run, it prints:

     message 1 >>> {"snowman": "\u2603", "set_value": [1, 2, 3]}

Note that the order of items might be different according to the version
of Python used.


File: python.info,  Node: Customizing handlers with dictConfig,  Next: Using particular formatting styles throughout your application,  Prev: Implementing structured logging,  Up: Logging Cookbook

9.9.23 Customizing handlers with ‘dictConfig()’
-----------------------------------------------

There are times when you want to customize logging handlers in
particular ways, and if you use *note dictConfig(): 11f4. you may be
able to do this without subclassing.  As an example, consider that you
may want to set the ownership of a log file.  On POSIX, this is easily
done using *note shutil.chown(): 240, but the file handlers in the
stdlib don’t offer built-in support.  You can customize handler creation
using a plain function such as:

     def owned_file_handler(filename, mode='a', encoding=None, owner=None):
         if owner:
             if not os.path.exists(filename):
                 open(filename, 'a').close()
             shutil.chown(filename, *owner)
         return logging.FileHandler(filename, mode, encoding)

You can then specify, in a logging configuration passed to *note
dictConfig(): 11f4, that a logging handler be created by calling this
function:

     LOGGING = {
         'version': 1,
         'disable_existing_loggers': False,
         'formatters': {
             'default': {
                 'format': '%(asctime)s %(levelname)s %(name)s %(message)s'
             },
         },
         'handlers': {
             'file':{
                 # The values below are popped from this dictionary and
                 # used to create the handler, set the handler's level and
                 # its formatter.
                 '()': owned_file_handler,
                 'level':'DEBUG',
                 'formatter': 'default',
                 # The values below are passed to the handler creator callable
                 # as keyword arguments.
                 'owner': ['pulse', 'pulse'],
                 'filename': 'chowntest.log',
                 'mode': 'w',
                 'encoding': 'utf-8',
             },
         },
         'root': {
             'handlers': ['file'],
             'level': 'DEBUG',
         },
     }

In this example I am setting the ownership using the ‘pulse’ user and
group, just for the purposes of illustration.  Putting it together into
a working script, ‘chowntest.py’:

     import logging, logging.config, os, shutil

     def owned_file_handler(filename, mode='a', encoding=None, owner=None):
         if owner:
             if not os.path.exists(filename):
                 open(filename, 'a').close()
             shutil.chown(filename, *owner)
         return logging.FileHandler(filename, mode, encoding)

     LOGGING = {
         'version': 1,
         'disable_existing_loggers': False,
         'formatters': {
             'default': {
                 'format': '%(asctime)s %(levelname)s %(name)s %(message)s'
             },
         },
         'handlers': {
             'file':{
                 # The values below are popped from this dictionary and
                 # used to create the handler, set the handler's level and
                 # its formatter.
                 '()': owned_file_handler,
                 'level':'DEBUG',
                 'formatter': 'default',
                 # The values below are passed to the handler creator callable
                 # as keyword arguments.
                 'owner': ['pulse', 'pulse'],
                 'filename': 'chowntest.log',
                 'mode': 'w',
                 'encoding': 'utf-8',
             },
         },
         'root': {
             'handlers': ['file'],
             'level': 'DEBUG',
         },
     }

     logging.config.dictConfig(LOGGING)
     logger = logging.getLogger('mylogger')
     logger.debug('A debug message')

To run this, you will probably need to run as ‘root’:

     $ sudo python3.3 chowntest.py
     $ cat chowntest.log
     2013-11-05 09:34:51,128 DEBUG mylogger A debug message
     $ ls -l chowntest.log
     -rw-r--r-- 1 pulse pulse 55 2013-11-05 09:34 chowntest.log

Note that this example uses Python 3.3 because that’s where *note
shutil.chown(): 240. makes an appearance.  This approach should work
with any Python version that supports *note dictConfig(): 11f4. -
namely, Python 2.7, 3.2 or later.  With pre-3.3 versions, you would need
to implement the actual ownership change using e.g.  *note os.chown():
1132.

In practice, the handler-creating function may be in a utility module
somewhere in your project.  Instead of the line in the configuration:

     '()': owned_file_handler,

you could use e.g.:

     '()': 'ext://project.util.owned_file_handler',

where ‘project.util’ can be replaced with the actual name of the package
where the function resides.  In the above working script, using
‘'ext://__main__.owned_file_handler'’ should work.  Here, the actual
callable is resolved by *note dictConfig(): 11f4. from the ‘ext://’
specification.

This example hopefully also points the way to how you could implement
other types of file change - e.g.  setting specific POSIX permission
bits - in the same way, using *note os.chmod(): 21b.

Of course, the approach could also be extended to types of handler other
than a *note FileHandler: 19f9. - for example, one of the rotating file
handlers, or a different type of handler altogether.


File: python.info,  Node: Using particular formatting styles throughout your application,  Next: Configuring filters with dictConfig,  Prev: Customizing handlers with dictConfig,  Up: Logging Cookbook

9.9.24 Using particular formatting styles throughout your application
---------------------------------------------------------------------

In Python 3.2, the *note Formatter: 14e6. gained a ‘style’ keyword
parameter which, while defaulting to ‘%’ for backward compatibility,
allowed the specification of ‘{’ or ‘$’ to support the formatting
approaches supported by *note str.format(): 624. and *note
string.Template: 68a.  Note that this governs the formatting of logging
messages for final output to logs, and is completely orthogonal to how
an individual logging message is constructed.

Logging calls (*note debug(): e5d, *note info(): 2e59. etc.)  only take
positional parameters for the actual logging message itself, with
keyword parameters used only for determining options for how to handle
the logging call (e.g.  the ‘exc_info’ keyword parameter to indicate
that traceback information should be logged, or the ‘extra’ keyword
parameter to indicate additional contextual information to be added to
the log).  So you cannot directly make logging calls using *note
str.format(): 624. or *note string.Template: 68a. syntax, because
internally the logging package uses %-formatting to merge the format
string and the variable arguments.  There would be no changing this
while preserving backward compatibility, since all logging calls which
are out there in existing code will be using %-format strings.

There have been suggestions to associate format styles with specific
loggers, but that approach also runs into backward compatibility
problems because any existing code could be using a given logger name
and using %-formatting.

For logging to work interoperably between any third-party libraries and
your code, decisions about formatting need to be made at the level of
the individual logging call.  This opens up a couple of ways in which
alternative formatting styles can be accommodated.

* Menu:

* Using LogRecord factories::
* Using custom message objects::


File: python.info,  Node: Using LogRecord factories,  Next: Using custom message objects,  Up: Using particular formatting styles throughout your application

9.9.24.1 Using LogRecord factories
..................................

In Python 3.2, along with the *note Formatter: 14e6. changes mentioned
above, the logging package gained the ability to allow users to set
their own *note LogRecord: 1021. subclasses, using the *note
setLogRecordFactory(): 2e8b. function.  You can use this to set your own
subclass of ‘LogRecord’, which does the Right Thing by overriding the
*note getMessage(): 2e89. method.  The base class implementation of this
method is where the ‘msg % args’ formatting happens, and where you can
substitute your alternate formatting; however, you should be careful to
support all formatting styles and allow %-formatting as the default, to
ensure interoperability with other code.  Care should also be taken to
call ‘str(self.msg)’, just as the base implementation does.

Refer to the reference documentation on *note setLogRecordFactory():
2e8b. and *note LogRecord: 1021. for more information.


File: python.info,  Node: Using custom message objects,  Prev: Using LogRecord factories,  Up: Using particular formatting styles throughout your application

9.9.24.2 Using custom message objects
.....................................

There is another, perhaps simpler way that you can use {}- and $-
formatting to construct your individual log messages.  You may recall
(from *note Using arbitrary objects as messages: 2e88.) that when
logging you can use an arbitrary object as a message format string, and
that the logging package will call *note str(): 44f. on that object to
get the actual format string.  Consider the following two classes:

     class BraceMessage:
         def __init__(self, fmt, /, *args, **kwargs):
             self.fmt = fmt
             self.args = args
             self.kwargs = kwargs

         def __str__(self):
             return self.fmt.format(*self.args, **self.kwargs)

     class DollarMessage:
         def __init__(self, fmt, /, **kwargs):
             self.fmt = fmt
             self.kwargs = kwargs

         def __str__(self):
             from string import Template
             return Template(self.fmt).substitute(**self.kwargs)

Either of these can be used in place of a format string, to allow {}- or
$-formatting to be used to build the actual “message” part which appears
in the formatted log output in place of “%(message)s” or “{message}” or
“$message”.  If you find it a little unwieldy to use the class names
whenever you want to log something, you can make it more palatable if
you use an alias such as ‘M’ or ‘_’ for the message (or perhaps ‘__’, if
you are using ‘_’ for localization).

Examples of this approach are given below.  Firstly, formatting with
*note str.format(): 624.:

     >>> __ = BraceMessage
     >>> print(__('Message with {0} {1}', 2, 'placeholders'))
     Message with 2 placeholders
     >>> class Point: pass
     ...
     >>> p = Point()
     >>> p.x = 0.5
     >>> p.y = 0.5
     >>> print(__('Message with coordinates: ({point.x:.2f}, {point.y:.2f})', point=p))
     Message with coordinates: (0.50, 0.50)

Secondly, formatting with *note string.Template: 68a.:

     >>> __ = DollarMessage
     >>> print(__('Message with $num $what', num=2, what='placeholders'))
     Message with 2 placeholders
     >>>

One thing to note is that you pay no significant performance penalty
with this approach: the actual formatting happens not when you make the
logging call, but when (and if) the logged message is actually about to
be output to a log by a handler.  So the only slightly unusual thing
which might trip you up is that the parentheses go around the format
string and the arguments, not just the format string.  That’s because
the __ notation is just syntax sugar for a constructor call to one of
the ‘XXXMessage’ classes shown above.


File: python.info,  Node: Configuring filters with dictConfig,  Next: Customized exception formatting,  Prev: Using particular formatting styles throughout your application,  Up: Logging Cookbook

9.9.25 Configuring filters with ‘dictConfig()’
----------------------------------------------

You 'can' configure filters using *note dictConfig(): 11f4, though it
might not be obvious at first glance how to do it (hence this recipe).
Since *note Filter: 1240. is the only filter class included in the
standard library, and it is unlikely to cater to many requirements (it’s
only there as a base class), you will typically need to define your own
‘Filter’ subclass with an overridden *note filter(): 2e82. method.  To
do this, specify the ‘()’ key in the configuration dictionary for the
filter, specifying a callable which will be used to create the filter (a
class is the most obvious, but you can provide any callable which
returns a ‘Filter’ instance).  Here is a complete example:

     import logging
     import logging.config
     import sys

     class MyFilter(logging.Filter):
         def __init__(self, param=None):
             self.param = param

         def filter(self, record):
             if self.param is None:
                 allow = True
             else:
                 allow = self.param not in record.msg
             if allow:
                 record.msg = 'changed: ' + record.msg
             return allow

     LOGGING = {
         'version': 1,
         'filters': {
             'myfilter': {
                 '()': MyFilter,
                 'param': 'noshow',
             }
         },
         'handlers': {
             'console': {
                 'class': 'logging.StreamHandler',
                 'filters': ['myfilter']
             }
         },
         'root': {
             'level': 'DEBUG',
             'handlers': ['console']
         },
     }

     if __name__ == '__main__':
         logging.config.dictConfig(LOGGING)
         logging.debug('hello')
         logging.debug('hello - noshow')

This example shows how you can pass configuration data to the callable
which constructs the instance, in the form of keyword parameters.  When
run, the above script will print:

     changed: hello

which shows that the filter is working as configured.

A couple of extra points to note:

   * If you can’t refer to the callable directly in the configuration
     (e.g.  if it lives in a different module, and you can’t import it
     directly where the configuration dictionary is), you can use the
     form ‘ext://...’ as described in *note Access to external objects:
     2eb8.  For example, you could have used the text
     ‘'ext://__main__.MyFilter'’ instead of ‘MyFilter’ in the above
     example.

   * As well as for filters, this technique can also be used to
     configure custom handlers and formatters.  See *note User-defined
     objects: 2eac. for more information on how logging supports using
     user-defined objects in its configuration, and see the other
     cookbook recipe *note Customizing handlers with dictConfig(): 5409.
     above.


File: python.info,  Node: Customized exception formatting,  Next: Speaking logging messages,  Prev: Configuring filters with dictConfig,  Up: Logging Cookbook

9.9.26 Customized exception formatting
--------------------------------------

There might be times when you want to do customized exception formatting
- for argument’s sake, let’s say you want exactly one line per logged
event, even when exception information is present.  You can do this with
a custom formatter class, as shown in the following example:

     import logging

     class OneLineExceptionFormatter(logging.Formatter):
         def formatException(self, exc_info):
             """
             Format an exception so that it prints on a single line.
             """
             result = super().formatException(exc_info)
             return repr(result)  # or format into one line however you want to

         def format(self, record):
             s = super().format(record)
             if record.exc_text:
                 s = s.replace('\n', '') + '|'
             return s

     def configure_logging():
         fh = logging.FileHandler('output.txt', 'w')
         f = OneLineExceptionFormatter('%(asctime)s|%(levelname)s|%(message)s|',
                                       '%d/%m/%Y %H:%M:%S')
         fh.setFormatter(f)
         root = logging.getLogger()
         root.setLevel(logging.DEBUG)
         root.addHandler(fh)

     def main():
         configure_logging()
         logging.info('Sample message')
         try:
             x = 1 / 0
         except ZeroDivisionError as e:
             logging.exception('ZeroDivisionError: %s', e)

     if __name__ == '__main__':
         main()

When run, this produces a file with exactly two lines:

     28/01/2015 07:21:23|INFO|Sample message|
     28/01/2015 07:21:23|ERROR|ZeroDivisionError: integer division or modulo by zero|'Traceback (most recent call last):\n  File "logtest7.py", line 30, in main\n    x = 1 / 0\nZeroDivisionError: integer division or modulo by zero'|

While the above treatment is simplistic, it points the way to how
exception information can be formatted to your liking.  The *note
traceback: fe. module may be helpful for more specialized needs.


File: python.info,  Node: Speaking logging messages,  Next: Buffering logging messages and outputting them conditionally,  Prev: Customized exception formatting,  Up: Logging Cookbook

9.9.27 Speaking logging messages
--------------------------------

There might be situations when it is desirable to have logging messages
rendered in an audible rather than a visible format.  This is easy to do
if you have text-to-speech (TTS) functionality available in your system,
even if it doesn’t have a Python binding.  Most TTS systems have a
command line program you can run, and this can be invoked from a handler
using *note subprocess: d6.  It’s assumed here that TTS command line
programs won’t expect to interact with users or take a long time to
complete, and that the frequency of logged messages will be not so high
as to swamp the user with messages, and that it’s acceptable to have the
messages spoken one at a time rather than concurrently, The example
implementation below waits for one message to be spoken before the next
is processed, and this might cause other handlers to be kept waiting.
Here is a short example showing the approach, which assumes that the
‘espeak’ TTS package is available:

     import logging
     import subprocess
     import sys

     class TTSHandler(logging.Handler):
         def emit(self, record):
             msg = self.format(record)
             # Speak slowly in a female English voice
             cmd = ['espeak', '-s150', '-ven+f3', msg]
             p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                  stderr=subprocess.STDOUT)
             # wait for the program to finish
             p.communicate()

     def configure_logging():
         h = TTSHandler()
         root = logging.getLogger()
         root.addHandler(h)
         # the default formatter just returns the message
         root.setLevel(logging.DEBUG)

     def main():
         logging.info('Hello')
         logging.debug('Goodbye')

     if __name__ == '__main__':
         configure_logging()
         sys.exit(main())

When run, this script should say “Hello” and then “Goodbye” in a female
voice.

The above approach can, of course, be adapted to other TTS systems and
even other systems altogether which can process messages via external
programs run from a command line.


File: python.info,  Node: Buffering logging messages and outputting them conditionally,  Next: Sending logging messages to email with buffering,  Prev: Speaking logging messages,  Up: Logging Cookbook

9.9.28 Buffering logging messages and outputting them conditionally
-------------------------------------------------------------------

There might be situations where you want to log messages in a temporary
area and only output them if a certain condition occurs.  For example,
you may want to start logging debug events in a function, and if the
function completes without errors, you don’t want to clutter the log
with the collected debug information, but if there is an error, you want
all the debug information to be output as well as the error.

Here is an example which shows how you could do this using a decorator
for your functions where you want logging to behave this way.  It makes
use of the *note logging.handlers.MemoryHandler: 2ebb, which allows
buffering of logged events until some condition occurs, at which point
the buffered events are ‘flushed’ - passed to another handler (the
‘target’ handler) for processing.  By default, the ‘MemoryHandler’
flushed when its buffer gets filled up or an event whose level is
greater than or equal to a specified threshold is seen.  You can use
this recipe with a more specialised subclass of ‘MemoryHandler’ if you
want custom flushing behavior.

The example script has a simple function, ‘foo’, which just cycles
through all the logging levels, writing to ‘sys.stderr’ to say what
level it’s about to log at, and then actually logging a message at that
level.  You can pass a parameter to ‘foo’ which, if true, will log at
ERROR and CRITICAL levels - otherwise, it only logs at DEBUG, INFO and
WARNING levels.

The script just arranges to decorate ‘foo’ with a decorator which will
do the conditional logging that’s required.  The decorator takes a
logger as a parameter and attaches a memory handler for the duration of
the call to the decorated function.  The decorator can be additionally
parameterised using a target handler, a level at which flushing should
occur, and a capacity for the buffer (number of records buffered).
These default to a *note StreamHandler: 123d. which writes to
‘sys.stderr’, ‘logging.ERROR’ and ‘100’ respectively.

Here’s the script:

     import logging
     from logging.handlers import MemoryHandler
     import sys

     logger = logging.getLogger(__name__)
     logger.addHandler(logging.NullHandler())

     def log_if_errors(logger, target_handler=None, flush_level=None, capacity=None):
         if target_handler is None:
             target_handler = logging.StreamHandler()
         if flush_level is None:
             flush_level = logging.ERROR
         if capacity is None:
             capacity = 100
         handler = MemoryHandler(capacity, flushLevel=flush_level, target=target_handler)

         def decorator(fn):
             def wrapper(*args, **kwargs):
                 logger.addHandler(handler)
                 try:
                     return fn(*args, **kwargs)
                 except Exception:
                     logger.exception('call failed')
                     raise
                 finally:
                     super(MemoryHandler, handler).flush()
                     logger.removeHandler(handler)
             return wrapper

         return decorator

     def write_line(s):
         sys.stderr.write('%s\n' % s)

     def foo(fail=False):
         write_line('about to log at DEBUG ...')
         logger.debug('Actually logged at DEBUG')
         write_line('about to log at INFO ...')
         logger.info('Actually logged at INFO')
         write_line('about to log at WARNING ...')
         logger.warning('Actually logged at WARNING')
         if fail:
             write_line('about to log at ERROR ...')
             logger.error('Actually logged at ERROR')
             write_line('about to log at CRITICAL ...')
             logger.critical('Actually logged at CRITICAL')
         return fail

     decorated_foo = log_if_errors(logger)(foo)

     if __name__ == '__main__':
         logger.setLevel(logging.DEBUG)
         write_line('Calling undecorated foo with False')
         assert not foo(False)
         write_line('Calling undecorated foo with True')
         assert foo(True)
         write_line('Calling decorated foo with False')
         assert not decorated_foo(False)
         write_line('Calling decorated foo with True')
         assert decorated_foo(True)

When this script is run, the following output should be observed:

     Calling undecorated foo with False
     about to log at DEBUG ...
     about to log at INFO ...
     about to log at WARNING ...
     Calling undecorated foo with True
     about to log at DEBUG ...
     about to log at INFO ...
     about to log at WARNING ...
     about to log at ERROR ...
     about to log at CRITICAL ...
     Calling decorated foo with False
     about to log at DEBUG ...
     about to log at INFO ...
     about to log at WARNING ...
     Calling decorated foo with True
     about to log at DEBUG ...
     about to log at INFO ...
     about to log at WARNING ...
     about to log at ERROR ...
     Actually logged at DEBUG
     Actually logged at INFO
     Actually logged at WARNING
     Actually logged at ERROR
     about to log at CRITICAL ...
     Actually logged at CRITICAL

As you can see, actual logging output only occurs when an event is
logged whose severity is ERROR or greater, but in that case, any
previous events at lower severities are also logged.

You can of course use the conventional means of decoration:

     @log_if_errors(logger)
     def foo(fail=False):
         ...


File: python.info,  Node: Sending logging messages to email with buffering,  Next: Formatting times using UTC GMT via configuration,  Prev: Buffering logging messages and outputting them conditionally,  Up: Logging Cookbook

9.9.29 Sending logging messages to email, with buffering
--------------------------------------------------------

To illustrate how you can send log messages via email, so that a set
number of messages are sent per email, you can subclass *note
BufferingHandler: 2f0e.  In the following example, which you can adapt
to suit your specific needs, a simple test harness is provided which
allows you to run the script with command line arguments specifying what
you typically need to send things via SMTP. (Run the downloaded script
with the ‘-h’ argument to see the required and optional arguments.)

     import logging
     import logging.handlers
     import smtplib

     class BufferingSMTPHandler(logging.handlers.BufferingHandler):
         def __init__(self, mailhost, port, username, password, fromaddr, toaddrs,
                      subject, capacity):
             logging.handlers.BufferingHandler.__init__(self, capacity)
             self.mailhost = mailhost
             self.mailport = port
             self.username = username
             self.password = password
             self.fromaddr = fromaddr
             if isinstance(toaddrs, str):
                 toaddrs = [toaddrs]
             self.toaddrs = toaddrs
             self.subject = subject
             self.setFormatter(logging.Formatter("%(asctime)s %(levelname)-5s %(message)s"))

         def flush(self):
             if len(self.buffer) > 0:
                 try:
                     smtp = smtplib.SMTP(self.mailhost, self.mailport)
                     smtp.starttls()
                     smtp.login(self.username, self.password)
                     msg = "From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n" % (self.fromaddr, ','.join(self.toaddrs), self.subject)
                     for record in self.buffer:
                         s = self.format(record)
                         msg = msg + s + "\r\n"
                     smtp.sendmail(self.fromaddr, self.toaddrs, msg)
                     smtp.quit()
                 except Exception:
                     if logging.raiseExceptions:
                         raise
                 self.buffer = []

     if __name__ == '__main__':
         import argparse

         ap = argparse.ArgumentParser()
         aa = ap.add_argument
         aa('host', metavar='HOST', help='SMTP server')
         aa('--port', '-p', type=int, default=587, help='SMTP port')
         aa('user', metavar='USER', help='SMTP username')
         aa('password', metavar='PASSWORD', help='SMTP password')
         aa('to', metavar='TO', help='Addressee for emails')
         aa('sender', metavar='SENDER', help='Sender email address')
         aa('--subject', '-s',
            default='Test Logging email from Python logging module (buffering)',
            help='Subject of email')
         options = ap.parse_args()
         logger = logging.getLogger()
         logger.setLevel(logging.DEBUG)
         h = BufferingSMTPHandler(options.host, options.port, options.user,
                                  options.password, options.sender,
                                  options.to, options.subject, 10)
         logger.addHandler(h)
         for i in range(102):
             logger.info("Info index = %d", i)
         h.flush()
         h.close()

If you run this script and your SMTP server is correctly set up, you
should find that it sends eleven emails to the addressee you specify.
The first ten emails will each have ten log messages, and the eleventh
will have two messages.  That makes up 102 messages as specified in the
script.


File: python.info,  Node: Formatting times using UTC GMT via configuration,  Next: Using a context manager for selective logging,  Prev: Sending logging messages to email with buffering,  Up: Logging Cookbook

9.9.30 Formatting times using UTC (GMT) via configuration
---------------------------------------------------------

Sometimes you want to format times using UTC, which can be done using a
class such as ‘UTCFormatter’, shown below:

     import logging
     import time

     class UTCFormatter(logging.Formatter):
         converter = time.gmtime

and you can then use the ‘UTCFormatter’ in your code instead of *note
Formatter: 14e6.  If you want to do that via configuration, you can use
the *note dictConfig(): 11f4. API with an approach illustrated by the
following complete example:

     import logging
     import logging.config
     import time

     class UTCFormatter(logging.Formatter):
         converter = time.gmtime

     LOGGING = {
         'version': 1,
         'disable_existing_loggers': False,
         'formatters': {
             'utc': {
                 '()': UTCFormatter,
                 'format': '%(asctime)s %(message)s',
             },
             'local': {
                 'format': '%(asctime)s %(message)s',
             }
         },
         'handlers': {
             'console1': {
                 'class': 'logging.StreamHandler',
                 'formatter': 'utc',
             },
             'console2': {
                 'class': 'logging.StreamHandler',
                 'formatter': 'local',
             },
         },
         'root': {
             'handlers': ['console1', 'console2'],
        }
     }

     if __name__ == '__main__':
         logging.config.dictConfig(LOGGING)
         logging.warning('The local time is %s', time.asctime())

When this script is run, it should print something like:

     2015-10-17 12:53:29,501 The local time is Sat Oct 17 13:53:29 2015
     2015-10-17 13:53:29,501 The local time is Sat Oct 17 13:53:29 2015

showing how the time is formatted both as local time and UTC, one for
each handler.


File: python.info,  Node: Using a context manager for selective logging,  Next: A CLI application starter template,  Prev: Formatting times using UTC GMT via configuration,  Up: Logging Cookbook

9.9.31 Using a context manager for selective logging
----------------------------------------------------

There are times when it would be useful to temporarily change the
logging configuration and revert it back after doing something.  For
this, a context manager is the most obvious way of saving and restoring
the logging context.  Here is a simple example of such a context
manager, which allows you to optionally change the logging level and add
a logging handler purely in the scope of the context manager:

     import logging
     import sys

     class LoggingContext:
         def __init__(self, logger, level=None, handler=None, close=True):
             self.logger = logger
             self.level = level
             self.handler = handler
             self.close = close

         def __enter__(self):
             if self.level is not None:
                 self.old_level = self.logger.level
                 self.logger.setLevel(self.level)
             if self.handler:
                 self.logger.addHandler(self.handler)

         def __exit__(self, et, ev, tb):
             if self.level is not None:
                 self.logger.setLevel(self.old_level)
             if self.handler:
                 self.logger.removeHandler(self.handler)
             if self.handler and self.close:
                 self.handler.close()
             # implicit return of None => don't swallow exceptions

If you specify a level value, the logger’s level is set to that value in
the scope of the with block covered by the context manager.  If you
specify a handler, it is added to the logger on entry to the block and
removed on exit from the block.  You can also ask the manager to close
the handler for you on block exit - you could do this if you don’t need
the handler any more.

To illustrate how it works, we can add the following block of code to
the above:

     if __name__ == '__main__':
         logger = logging.getLogger('foo')
         logger.addHandler(logging.StreamHandler())
         logger.setLevel(logging.INFO)
         logger.info('1. This should appear just once on stderr.')
         logger.debug('2. This should not appear.')
         with LoggingContext(logger, level=logging.DEBUG):
             logger.debug('3. This should appear once on stderr.')
         logger.debug('4. This should not appear.')
         h = logging.StreamHandler(sys.stdout)
         with LoggingContext(logger, level=logging.DEBUG, handler=h, close=True):
             logger.debug('5. This should appear twice - once on stderr and once on stdout.')
         logger.info('6. This should appear just once on stderr.')
         logger.debug('7. This should not appear.')

We initially set the logger’s level to ‘INFO’, so message #1 appears and
message #2 doesn’t.  We then change the level to ‘DEBUG’ temporarily in
the following ‘with’ block, and so message #3 appears.  After the block
exits, the logger’s level is restored to ‘INFO’ and so message #4
doesn’t appear.  In the next ‘with’ block, we set the level to ‘DEBUG’
again but also add a handler writing to ‘sys.stdout’.  Thus, message #5
appears twice on the console (once via ‘stderr’ and once via ‘stdout’).
After the ‘with’ statement’s completion, the status is as it was before
so message #6 appears (like message #1) whereas message #7 doesn’t (just
like message #2).

If we run the resulting script, the result is as follows:

     $ python logctx.py
     1. This should appear just once on stderr.
     3. This should appear once on stderr.
     5. This should appear twice - once on stderr and once on stdout.
     5. This should appear twice - once on stderr and once on stdout.
     6. This should appear just once on stderr.

If we run it again, but pipe ‘stderr’ to ‘/dev/null’, we see the
following, which is the only message written to ‘stdout’:

     $ python logctx.py 2>/dev/null
     5. This should appear twice - once on stderr and once on stdout.

Once again, but piping ‘stdout’ to ‘/dev/null’, we get:

     $ python logctx.py >/dev/null
     1. This should appear just once on stderr.
     3. This should appear once on stderr.
     5. This should appear twice - once on stderr and once on stdout.
     6. This should appear just once on stderr.

In this case, the message #5 printed to ‘stdout’ doesn’t appear, as
expected.

Of course, the approach described here can be generalised, for example
to attach logging filters temporarily.  Note that the above code works
in Python 2 as well as Python 3.


File: python.info,  Node: A CLI application starter template,  Next: A Qt GUI for logging,  Prev: Using a context manager for selective logging,  Up: Logging Cookbook

9.9.32 A CLI application starter template
-----------------------------------------

Here’s an example which shows how you can:

   * Use a logging level based on command-line arguments

   * Dispatch to multiple subcommands in separate files, all logging at
     the same level in a consistent way

   * Make use of simple, minimal configuration

Suppose we have a command-line application whose job is to stop, start
or restart some services.  This could be organised for the purposes of
illustration as a file ‘app.py’ that is the main script for the
application, with individual commands implemented in ‘start.py’,
‘stop.py’ and ‘restart.py’.  Suppose further that we want to control the
verbosity of the application via a command-line argument, defaulting to
‘logging.INFO’.  Here’s one way that ‘app.py’ could be written:

     import argparse
     import importlib
     import logging
     import os
     import sys

     def main(args=None):
         scriptname = os.path.basename(__file__)
         parser = argparse.ArgumentParser(scriptname)
         levels = ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL')
         parser.add_argument('--log-level', default='INFO', choices=levels)
         subparsers = parser.add_subparsers(dest='command',
                                            help='Available commands:')
         start_cmd = subparsers.add_parser('start', help='Start a service')
         start_cmd.add_argument('name', metavar='NAME',
                                help='Name of service to start')
         stop_cmd = subparsers.add_parser('stop',
                                          help='Stop one or more services')
         stop_cmd.add_argument('names', metavar='NAME', nargs='+',
                               help='Name of service to stop')
         restart_cmd = subparsers.add_parser('restart',
                                             help='Restart one or more services')
         restart_cmd.add_argument('names', metavar='NAME', nargs='+',
                                  help='Name of service to restart')
         options = parser.parse_args()
         # the code to dispatch commands could all be in this file. For the purposes
         # of illustration only, we implement each command in a separate module.
         try:
             mod = importlib.import_module(options.command)
             cmd = getattr(mod, 'command')
         except (ImportError, AttributeError):
             print('Unable to find the code for command \'%s\'' % options.command)
             return 1
         # Could get fancy here and load configuration from file or dictionary
         logging.basicConfig(level=options.log_level,
                             format='%(levelname)s %(name)s %(message)s')
         cmd(options)

     if __name__ == '__main__':
         sys.exit(main())

And the ‘start’, ‘stop’ and ‘restart’ commands can be implemented in
separate modules, like so for starting:

     # start.py
     import logging

     logger = logging.getLogger(__name__)

     def command(options):
         logger.debug('About to start %s', options.name)
         # actually do the command processing here ...
         logger.info('Started the \'%s\' service.', options.name)

and thus for stopping:

     # stop.py
     import logging

     logger = logging.getLogger(__name__)

     def command(options):
         n = len(options.names)
         if n == 1:
             plural = ''
             services = '\'%s\'' % options.names[0]
         else:
             plural = 's'
             services = ', '.join('\'%s\'' % name for name in options.names)
             i = services.rfind(', ')
             services = services[:i] + ' and ' + services[i + 2:]
         logger.debug('About to stop %s', services)
         # actually do the command processing here ...
         logger.info('Stopped the %s service%s.', services, plural)

and similarly for restarting:

     # restart.py
     import logging

     logger = logging.getLogger(__name__)

     def command(options):
         n = len(options.names)
         if n == 1:
             plural = ''
             services = '\'%s\'' % options.names[0]
         else:
             plural = 's'
             services = ', '.join('\'%s\'' % name for name in options.names)
             i = services.rfind(', ')
             services = services[:i] + ' and ' + services[i + 2:]
         logger.debug('About to restart %s', services)
         # actually do the command processing here ...
         logger.info('Restarted the %s service%s.', services, plural)

If we run this application with the default log level, we get output
like this:

     $ python app.py start foo
     INFO start Started the 'foo' service.

     $ python app.py stop foo bar
     INFO stop Stopped the 'foo' and 'bar' services.

     $ python app.py restart foo bar baz
     INFO restart Restarted the 'foo', 'bar' and 'baz' services.

The first word is the logging level, and the second word is the module
or package name of the place where the event was logged.

If we change the logging level, then we can change the information sent
to the log.  For example, if we want more information:

     $ python app.py --log-level DEBUG start foo
     DEBUG start About to start foo
     INFO start Started the 'foo' service.

     $ python app.py --log-level DEBUG stop foo bar
     DEBUG stop About to stop 'foo' and 'bar'
     INFO stop Stopped the 'foo' and 'bar' services.

     $ python app.py --log-level DEBUG restart foo bar baz
     DEBUG restart About to restart 'foo', 'bar' and 'baz'
     INFO restart Restarted the 'foo', 'bar' and 'baz' services.

And if we want less:

     $ python app.py --log-level WARNING start foo
     $ python app.py --log-level WARNING stop foo bar
     $ python app.py --log-level WARNING restart foo bar baz

In this case, the commands don’t print anything to the console, since
nothing at ‘WARNING’ level or above is logged by them.


File: python.info,  Node: A Qt GUI for logging,  Next: Logging to syslog with RFC5424 support,  Prev: A CLI application starter template,  Up: Logging Cookbook

9.9.33 A Qt GUI for logging
---------------------------

A question that comes up from time to time is about how to log to a GUI
application.  The Qt(1) framework is a popular cross-platform UI
framework with Python bindings using PySide2(2) or PyQt5(3) libraries.

The following example shows how to log to a Qt GUI. This introduces a
simple ‘QtHandler’ class which takes a callable, which should be a slot
in the main thread that does GUI updates.  A worker thread is also
created to show how you can log to the GUI from both the UI itself (via
a button for manual logging) as well as a worker thread doing work in
the background (here, just logging messages at random levels with random
short delays in between).

The worker thread is implemented using Qt’s ‘QThread’ class rather than
the *note threading: ed. module, as there are circumstances where one
has to use ‘QThread’, which offers better integration with other ‘Qt’
components.

The code should work with recent releases of any of ‘PySide6’, ‘PyQt6’,
‘PySide2’ or ‘PyQt5’.  You should be able to adapt the approach to
earlier versions of Qt.  Please refer to the comments in the code
snippet for more detailed information.

     import logging
     import random
     import sys
     import time

     # Deal with minor differences between different Qt packages
     try:
         from PySide6 import QtCore, QtGui, QtWidgets
         Signal = QtCore.Signal
         Slot = QtCore.Slot
     except ImportError:
         try:
             from PyQt6 import QtCore, QtGui, QtWidgets
             Signal = QtCore.pyqtSignal
             Slot = QtCore.pyqtSlot
         except ImportError:
             try:
                 from PySide2 import QtCore, QtGui, QtWidgets
                 Signal = QtCore.Signal
                 Slot = QtCore.Slot
             except ImportError:
                 from PyQt5 import QtCore, QtGui, QtWidgets
                 Signal = QtCore.pyqtSignal
                 Slot = QtCore.pyqtSlot

     logger = logging.getLogger(__name__)


     #
     # Signals need to be contained in a QObject or subclass in order to be correctly
     # initialized.
     #
     class Signaller(QtCore.QObject):
         signal = Signal(str, logging.LogRecord)

     #
     # Output to a Qt GUI is only supposed to happen on the main thread. So, this
     # handler is designed to take a slot function which is set up to run in the main
     # thread. In this example, the function takes a string argument which is a
     # formatted log message, and the log record which generated it. The formatted
     # string is just a convenience - you could format a string for output any way
     # you like in the slot function itself.
     #
     # You specify the slot function to do whatever GUI updates you want. The handler
     # doesn't know or care about specific UI elements.
     #
     class QtHandler(logging.Handler):
         def __init__(self, slotfunc, *args, **kwargs):
             super().__init__(*args, **kwargs)
             self.signaller = Signaller()
             self.signaller.signal.connect(slotfunc)

         def emit(self, record):
             s = self.format(record)
             self.signaller.signal.emit(s, record)

     #
     # This example uses QThreads, which means that the threads at the Python level
     # are named something like "Dummy-1". The function below gets the Qt name of the
     # current thread.
     #
     def ctname():
         return QtCore.QThread.currentThread().objectName()


     #
     # Used to generate random levels for logging.
     #
     LEVELS = (logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR,
               logging.CRITICAL)

     #
     # This worker class represents work that is done in a thread separate to the
     # main thread. The way the thread is kicked off to do work is via a button press
     # that connects to a slot in the worker.
     #
     # Because the default threadName value in the LogRecord isn't much use, we add
     # a qThreadName which contains the QThread name as computed above, and pass that
     # value in an "extra" dictionary which is used to update the LogRecord with the
     # QThread name.
     #
     # This example worker just outputs messages sequentially, interspersed with
     # random delays of the order of a few seconds.
     #
     class Worker(QtCore.QObject):
         @Slot()
         def start(self):
             extra = {'qThreadName': ctname() }
             logger.debug('Started work', extra=extra)
             i = 1
             # Let the thread run until interrupted. This allows reasonably clean
             # thread termination.
             while not QtCore.QThread.currentThread().isInterruptionRequested():
                 delay = 0.5 + random.random() * 2
                 time.sleep(delay)
                 try:
                     if random.random() < 0.1:
                         raise ValueError('Exception raised: %d' % i)
                     else:
                         level = random.choice(LEVELS)
                         logger.log(level, 'Message after delay of %3.1f: %d', delay, i, extra=extra)
                 except ValueError as e:
                     logger.exception('Failed: %s', e, extra=extra)
                 i += 1

     #
     # Implement a simple UI for this cookbook example. This contains:
     #
     # * A read-only text edit window which holds formatted log messages
     # * A button to start work and log stuff in a separate thread
     # * A button to log something from the main thread
     # * A button to clear the log window
     #
     class Window(QtWidgets.QWidget):

         COLORS = {
             logging.DEBUG: 'black',
             logging.INFO: 'blue',
             logging.WARNING: 'orange',
             logging.ERROR: 'red',
             logging.CRITICAL: 'purple',
         }

         def __init__(self, app):
             super().__init__()
             self.app = app
             self.textedit = te = QtWidgets.QPlainTextEdit(self)
             # Set whatever the default monospace font is for the platform
             f = QtGui.QFont('nosuchfont')
             if hasattr(f, 'Monospace'):
                 f.setStyleHint(f.Monospace)
             else:
                 f.setStyleHint(f.StyleHint.Monospace)  # for Qt6
             te.setFont(f)
             te.setReadOnly(True)
             PB = QtWidgets.QPushButton
             self.work_button = PB('Start background work', self)
             self.log_button = PB('Log a message at a random level', self)
             self.clear_button = PB('Clear log window', self)
             self.handler = h = QtHandler(self.update_status)
             # Remember to use qThreadName rather than threadName in the format string.
             fs = '%(asctime)s %(qThreadName)-12s %(levelname)-8s %(message)s'
             formatter = logging.Formatter(fs)
             h.setFormatter(formatter)
             logger.addHandler(h)
             # Set up to terminate the QThread when we exit
             app.aboutToQuit.connect(self.force_quit)

             # Lay out all the widgets
             layout = QtWidgets.QVBoxLayout(self)
             layout.addWidget(te)
             layout.addWidget(self.work_button)
             layout.addWidget(self.log_button)
             layout.addWidget(self.clear_button)
             self.setFixedSize(900, 400)

             # Connect the non-worker slots and signals
             self.log_button.clicked.connect(self.manual_update)
             self.clear_button.clicked.connect(self.clear_display)

             # Start a new worker thread and connect the slots for the worker
             self.start_thread()
             self.work_button.clicked.connect(self.worker.start)
             # Once started, the button should be disabled
             self.work_button.clicked.connect(lambda : self.work_button.setEnabled(False))

         def start_thread(self):
             self.worker = Worker()
             self.worker_thread = QtCore.QThread()
             self.worker.setObjectName('Worker')
             self.worker_thread.setObjectName('WorkerThread')  # for qThreadName
             self.worker.moveToThread(self.worker_thread)
             # This will start an event loop in the worker thread
             self.worker_thread.start()

         def kill_thread(self):
             # Just tell the worker to stop, then tell it to quit and wait for that
             # to happen
             self.worker_thread.requestInterruption()
             if self.worker_thread.isRunning():
                 self.worker_thread.quit()
                 self.worker_thread.wait()
             else:
                 print('worker has already exited.')

         def force_quit(self):
             # For use when the window is closed
             if self.worker_thread.isRunning():
                 self.kill_thread()

         # The functions below update the UI and run in the main thread because
         # that's where the slots are set up

         @Slot(str, logging.LogRecord)
         def update_status(self, status, record):
             color = self.COLORS.get(record.levelno, 'black')
             s = '<pre><font color="%s">%s</font></pre>' % (color, status)
             self.textedit.appendHtml(s)

         @Slot()
         def manual_update(self):
             # This function uses the formatted message passed in, but also uses
             # information from the record to format the message in an appropriate
             # color according to its severity (level).
             level = random.choice(LEVELS)
             extra = {'qThreadName': ctname() }
             logger.log(level, 'Manually logged!', extra=extra)

         @Slot()
         def clear_display(self):
             self.textedit.clear()


     def main():
         QtCore.QThread.currentThread().setObjectName('MainThread')
         logging.getLogger().setLevel(logging.DEBUG)
         app = QtWidgets.QApplication(sys.argv)
         example = Window(app)
         example.show()
         if hasattr(app, 'exec'):
             rc = app.exec()
         else:
             rc = app.exec_()
         sys.exit(rc)

     if __name__=='__main__':
         main()

   ---------- Footnotes ----------

   (1) https://www.qt.io/

   (2) https://pypi.org/project/PySide2/

   (3) https://pypi.org/project/PyQt5/


File: python.info,  Node: Logging to syslog with RFC5424 support,  Next: How to treat a logger like an output stream,  Prev: A Qt GUI for logging,  Up: Logging Cookbook

9.9.34 Logging to syslog with RFC5424 support
---------------------------------------------

Although RFC 5424(1) dates from 2009, most syslog servers are configured
by default to use the older RFC 3164(2), which hails from 2001.  When
‘logging’ was added to Python in 2003, it supported the earlier (and
only existing) protocol at the time.  Since RFC 5424 came out, as there
has not been widespread deployment of it in syslog servers, the *note
SysLogHandler: 65f. functionality has not been updated.

RFC 5424 contains some useful features such as support for structured
data, and if you need to be able to log to a syslog server with support
for it, you can do so with a subclassed handler which looks something
like this:

     import datetime as dt
     import logging.handlers
     import re
     import socket
     import time

     class SysLogHandler5424(logging.handlers.SysLogHandler):

         tz_offset = re.compile(r'([+-]\d{2})(\d{2})$')
         escaped = re.compile(r'([\]"\\])')

         def __init__(self, *args, **kwargs):
             self.msgid = kwargs.pop('msgid', None)
             self.appname = kwargs.pop('appname', None)
             super().__init__(*args, **kwargs)

         def format(self, record):
             version = 1
             asctime = dt.datetime.fromtimestamp(record.created).isoformat()
             m = self.tz_offset.match(time.strftime('%z'))
             has_offset = False
             if m and time.timezone:
                 hrs, mins = m.groups()
                 if int(hrs) or int(mins):
                     has_offset = True
             if not has_offset:
                 asctime += 'Z'
             else:
                 asctime += f'{hrs}:{mins}'
             try:
                 hostname = socket.gethostname()
             except Exception:
                 hostname = '-'
             appname = self.appname or '-'
             procid = record.process
             msgid = '-'
             msg = super().format(record)
             sdata = '-'
             if hasattr(record, 'structured_data'):
                 sd = record.structured_data
                 # This should be a dict where the keys are SD-ID and the value is a
                 # dict mapping PARAM-NAME to PARAM-VALUE (refer to the RFC for what these
                 # mean)
                 # There's no error checking here - it's purely for illustration, and you
                 # can adapt this code for use in production environments
                 parts = []

                 def replacer(m):
                     g = m.groups()
                     return '\\' + g[0]

                 for sdid, dv in sd.items():
                     part = f'[{sdid}'
                     for k, v in dv.items():
                         s = str(v)
                         s = self.escaped.sub(replacer, s)
                         part += f' {k}="{s}"'
                     part += ']'
                     parts.append(part)
                 sdata = ''.join(parts)
             return f'{version} {asctime} {hostname} {appname} {procid} {msgid} {sdata} {msg}'

You’ll need to be familiar with RFC 5424 to fully understand the above
code, and it may be that you have slightly different needs (e.g.  for
how you pass structural data to the log).  Nevertheless, the above
should be adaptable to your speciric needs.  With the above handler,
you’d pass structured data using something like this:

     sd = {
         'foo@12345': {'bar': 'baz', 'baz': 'bozz', 'fizz': r'buzz'},
         'foo@54321': {'rab': 'baz', 'zab': 'bozz', 'zzif': r'buzz'}
     }
     extra = {'structured_data': sd}
     i = 1
     logger.debug('Message %d', i, extra=extra)

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc5424.html

   (2) https://datatracker.ietf.org/doc/html/rfc3164.html


File: python.info,  Node: How to treat a logger like an output stream,  Next: How to uniformly handle newlines in logging output,  Prev: Logging to syslog with RFC5424 support,  Up: Logging Cookbook

9.9.35 How to treat a logger like an output stream
--------------------------------------------------

Sometimes, you need to interface to a third-party API which expects a
file-like object to write to, but you want to direct the API’s output to
a logger.  You can do this using a class which wraps a logger with a
file-like API. Here’s a short script illustrating such a class:

     import logging

     class LoggerWriter:
         def __init__(self, logger, level):
             self.logger = logger
             self.level = level

         def write(self, message):
             if message != '\n':  # avoid printing bare newlines, if you like
                 self.logger.log(self.level, message)

         def flush(self):
             # doesn't actually do anything, but might be expected of a file-like
             # object - so optional depending on your situation
             pass

         def close(self):
             # doesn't actually do anything, but might be expected of a file-like
             # object - so optional depending on your situation. You might want
             # to set a flag so that later calls to write raise an exception
             pass

     def main():
         logging.basicConfig(level=logging.DEBUG)
         logger = logging.getLogger('demo')
         info_fp = LoggerWriter(logger, logging.INFO)
         debug_fp = LoggerWriter(logger, logging.DEBUG)
         print('An INFO message', file=info_fp)
         print('A DEBUG message', file=debug_fp)

     if __name__ == "__main__":
         main()

When this script is run, it prints

     INFO:demo:An INFO message
     DEBUG:demo:A DEBUG message

You could also use ‘LoggerWriter’ to redirect ‘sys.stdout’ and
‘sys.stderr’ by doing something like this:

     import sys

     sys.stdout = LoggerWriter(logger, logging.INFO)
     sys.stderr = LoggerWriter(logger, logging.WARNING)

You should do this 'after' configuring logging for your needs.  In the
above example, the *note basicConfig(): a0b. call does this (using the
‘sys.stderr’ value 'before' it is overwritten by a ‘LoggerWriter’
instance).  Then, you’d get this kind of result:

     >>> print('Foo')
     INFO:demo:Foo
     >>> print('Bar', file=sys.stderr)
     WARNING:demo:Bar
     >>>

Of course, the examples above show output according to the format used
by *note basicConfig(): a0b, but you can use a different formatter when
you configure logging.

Note that with the above scheme, you are somewhat at the mercy of
buffering and the sequence of write calls which you are intercepting.
For example, with the definition of ‘LoggerWriter’ above, if you have
the snippet

     sys.stderr = LoggerWriter(logger, logging.WARNING)
     1 / 0

then running the script results in

     WARNING:demo:Traceback (most recent call last):

     WARNING:demo:  File "/home/runner/cookbook-loggerwriter/test.py", line 53, in <module>

     WARNING:demo:
     WARNING:demo:main()
     WARNING:demo:  File "/home/runner/cookbook-loggerwriter/test.py", line 49, in main

     WARNING:demo:
     WARNING:demo:1 / 0
     WARNING:demo:ZeroDivisionError
     WARNING:demo::
     WARNING:demo:division by zero

As you can see, this output isn’t ideal.  That’s because the underlying
code which writes to ‘sys.stderr’ makes multiple writes, each of which
results in a separate logged line (for example, the last three lines
above).  To get around this problem, you need to buffer things and only
output log lines when newlines are seen.  Let’s use a slightly better
implementation of ‘LoggerWriter’:

     class BufferingLoggerWriter(LoggerWriter):
         def __init__(self, logger, level):
             super().__init__(logger, level)
             self.buffer = ''

         def write(self, message):
             if '\n' not in message:
                 self.buffer += message
             else:
                 parts = message.split('\n')
                 if self.buffer:
                     s = self.buffer + parts.pop(0)
                     self.logger.log(self.level, s)
                 self.buffer = parts.pop()
                 for part in parts:
                     self.logger.log(self.level, part)

This just buffers up stuff until a newline is seen, and then logs
complete lines.  With this approach, you get better output:

     WARNING:demo:Traceback (most recent call last):
     WARNING:demo:  File "/home/runner/cookbook-loggerwriter/main.py", line 55, in <module>
     WARNING:demo:    main()
     WARNING:demo:  File "/home/runner/cookbook-loggerwriter/main.py", line 52, in main
     WARNING:demo:    1/0
     WARNING:demo:ZeroDivisionError: division by zero


File: python.info,  Node: How to uniformly handle newlines in logging output,  Next: Patterns to avoid,  Prev: How to treat a logger like an output stream,  Up: Logging Cookbook

9.9.36 How to uniformly handle newlines in logging output
---------------------------------------------------------

Usually, messages that are logged (say to console or file) consist of a
single line of text.  However, sometimes there is a need to handle
messages with multiple lines - whether because a logging format string
contains newlines, or logged data contains newlines.  If you want to
handle such messages uniformly, so that each line in the logged message
appears uniformly formatted as if it was logged separately, you can do
this using a handler mixin, as in the following snippet:

     # Assume this is in a module mymixins.py
     import copy

     class MultilineMixin:
         def emit(self, record):
             s = record.getMessage()
             if '\n' not in s:
                 super().emit(record)
             else:
                 lines = s.splitlines()
                 rec = copy.copy(record)
                 rec.args = None
                 for line in lines:
                     rec.msg = line
                     super().emit(rec)

You can use the mixin as in the following script:

     import logging

     from mymixins import MultilineMixin

     logger = logging.getLogger(__name__)

     class StreamHandler(MultilineMixin, logging.StreamHandler):
         pass

     if __name__ == '__main__':
         logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)-9s %(message)s',
                             handlers = [StreamHandler()])
         logger.debug('Single line')
         logger.debug('Multiple lines:\nfool me once ...')
         logger.debug('Another single line')
         logger.debug('Multiple lines:\n%s', 'fool me ...\ncan\'t get fooled again')

The script, when run, prints something like:

     2025-07-02 13:54:47,234 DEBUG     Single line
     2025-07-02 13:54:47,234 DEBUG     Multiple lines:
     2025-07-02 13:54:47,234 DEBUG     fool me once ...
     2025-07-02 13:54:47,234 DEBUG     Another single line
     2025-07-02 13:54:47,234 DEBUG     Multiple lines:
     2025-07-02 13:54:47,234 DEBUG     fool me ...
     2025-07-02 13:54:47,234 DEBUG     can't get fooled again

If, on the other hand, you are concerned about log injection(1), you can
use a formatter which escapes newlines, as per the following example:

     import logging

     logger = logging.getLogger(__name__)

     class EscapingFormatter(logging.Formatter):
         def format(self, record):
             s = super().format(record)
             return s.replace('\n', r'\n')

     if __name__ == '__main__':
         h = logging.StreamHandler()
         h.setFormatter(EscapingFormatter('%(asctime)s %(levelname)-9s %(message)s'))
         logging.basicConfig(level=logging.DEBUG, handlers = [h])
         logger.debug('Single line')
         logger.debug('Multiple lines:\nfool me once ...')
         logger.debug('Another single line')
         logger.debug('Multiple lines:\n%s', 'fool me ...\ncan\'t get fooled again')

You can, of course, use whatever escaping scheme makes the most sense
for you.  The script, when run, should produce output like this:

     2025-07-09 06:47:33,783 DEBUG     Single line
     2025-07-09 06:47:33,783 DEBUG     Multiple lines:\nfool me once ...
     2025-07-09 06:47:33,783 DEBUG     Another single line
     2025-07-09 06:47:33,783 DEBUG     Multiple lines:\nfool me ...\ncan't get fooled again

Escaping behaviour can’t be the stdlib default , as it would break
backwards compatibility.

   ---------- Footnotes ----------

   (1) https://owasp.org/www-community/attacks/Log_Injection


File: python.info,  Node: Patterns to avoid,  Next: Other resources<2>,  Prev: How to uniformly handle newlines in logging output,  Up: Logging Cookbook

9.9.37 Patterns to avoid
------------------------

Although the preceding sections have described ways of doing things you
might need to do or deal with, it is worth mentioning some usage
patterns which are 'unhelpful', and which should therefore be avoided in
most cases.  The following sections are in no particular order.

* Menu:

* Opening the same log file multiple times::
* Using loggers as attributes in a class or passing them as parameters::
* Adding handlers other than NullHandler to a logger in a library::
* Creating a lot of loggers::


File: python.info,  Node: Opening the same log file multiple times,  Next: Using loggers as attributes in a class or passing them as parameters,  Up: Patterns to avoid

9.9.37.1 Opening the same log file multiple times
.................................................

On Windows, you will generally not be able to open the same file
multiple times as this will lead to a “file is in use by another
process” error.  However, on POSIX platforms you’ll not get any errors
if you open the same file multiple times.  This could be done
accidentally, for example by:

   * Adding a file handler more than once which references the same file
     (e.g.  by a copy/paste/forget-to-change error).

   * Opening two files that look different, as they have different
     names, but are the same because one is a symbolic link to the
     other.

   * Forking a process, following which both parent and child have a
     reference to the same file.  This might be through use of the *note
     multiprocessing: 94. module, for example.

Opening a file multiple times might 'appear' to work most of the time,
but can lead to a number of problems in practice:

   * Logging output can be garbled because multiple threads or processes
     try to write to the same file.  Although logging guards against
     concurrent use of the same handler instance by multiple threads,
     there is no such protection if concurrent writes are attempted by
     two different threads using two different handler instances which
     happen to point to the same file.

   * An attempt to delete a file (e.g.  during file rotation) silently
     fails, because there is another reference pointing to it.  This can
     lead to confusion and wasted debugging time - log entries end up in
     unexpected places, or are lost altogether.  Or a file that was
     supposed to be moved remains in place, and grows in size
     unexpectedly despite size-based rotation being supposedly in place.

Use the techniques outlined in *note Logging to a single file from
multiple processes: 53f4. to circumvent such issues.


File: python.info,  Node: Using loggers as attributes in a class or passing them as parameters,  Next: Adding handlers other than NullHandler to a logger in a library,  Prev: Opening the same log file multiple times,  Up: Patterns to avoid

9.9.37.2 Using loggers as attributes in a class or passing them as parameters
.............................................................................

While there might be unusual cases where you’ll need to do this, in
general there is no point because loggers are singletons.  Code can
always access a given logger instance by name using
‘logging.getLogger(name)’, so passing instances around and holding them
as instance attributes is pointless.  Note that in other languages such
as Java and C#, loggers are often static class attributes.  However,
this pattern doesn’t make sense in Python, where the module (and not the
class) is the unit of software decomposition.


File: python.info,  Node: Adding handlers other than NullHandler to a logger in a library,  Next: Creating a lot of loggers,  Prev: Using loggers as attributes in a class or passing them as parameters,  Up: Patterns to avoid

9.9.37.3 Adding handlers other than ‘NullHandler’ to a logger in a library
..........................................................................

Configuring logging by adding handlers, formatters and filters is the
responsibility of the application developer, not the library developer.
If you are maintaining a library, ensure that you don’t add handlers to
any of your loggers other than a *note NullHandler: 12cb. instance.


File: python.info,  Node: Creating a lot of loggers,  Prev: Adding handlers other than NullHandler to a logger in a library,  Up: Patterns to avoid

9.9.37.4 Creating a lot of loggers
..................................

Loggers are singletons that are never freed during a script execution,
and so creating lots of loggers will use up memory which can’t then be
freed.  Rather than create a logger per e.g.  file processed or network
connection made, use the *note existing mechanisms: 2e8f. for passing
contextual information into your logs and restrict the loggers created
to those describing areas within your application (generally modules,
but occasionally slightly more fine-grained than that).


File: python.info,  Node: Other resources<2>,  Prev: Patterns to avoid,  Up: Logging Cookbook

9.9.38 Other resources
----------------------

See also
........

Module *note logging: 87.

     API reference for the logging module.

Module *note logging.config: 88.

     Configuration API for the logging module.

Module *note logging.handlers: 89.

     Useful handlers included with the logging module.

*note Basic Tutorial: 123a.

*note Advanced Tutorial: 123b.


File: python.info,  Node: Regular expression HOWTO,  Next: Socket Programming HOWTO,  Prev: Logging Cookbook,  Up: Python HOWTOs

9.10 Regular expression HOWTO
=============================


Author: A.M. Kuchling <<amk@amk.ca>>

Abstract
........

This document is an introductory tutorial to using regular expressions
in Python with the *note re: b9. module.  It provides a gentler
introduction than the corresponding section in the Library Reference.

* Menu:

* Introduction: Introduction<15>.
* Simple patterns::
* Using regular expressions::
* More pattern power::
* Modifying strings::
* Common problems::
* Feedback::


File: python.info,  Node: Introduction<15>,  Next: Simple patterns,  Up: Regular expression HOWTO

9.10.1 Introduction
-------------------

Regular expressions (called REs, or regexes, or regex patterns) are
essentially a tiny, highly specialized programming language embedded
inside Python and made available through the *note re: b9. module.
Using this little language, you specify the rules for the set of
possible strings that you want to match; this set might contain English
sentences, or e-mail addresses, or TeX commands, or anything you like.
You can then ask questions such as “Does this string match the
pattern?”, or “Is there a match for the pattern anywhere in this
string?”.  You can also use REs to modify a string or to split it apart
in various ways.

Regular expression patterns are compiled into a series of bytecodes
which are then executed by a matching engine written in C. For advanced
use, it may be necessary to pay careful attention to how the engine will
execute a given RE, and write the RE in a certain way in order to
produce bytecode that runs faster.  Optimization isn’t covered in this
document, because it requires that you have a good understanding of the
matching engine’s internals.

The regular expression language is relatively small and restricted, so
not all possible string processing tasks can be done using regular
expressions.  There are also tasks that 'can' be done with regular
expressions, but the expressions turn out to be very complicated.  In
these cases, you may be better off writing Python code to do the
processing; while Python code will be slower than an elaborate regular
expression, it will also probably be more understandable.


File: python.info,  Node: Simple patterns,  Next: Using regular expressions,  Prev: Introduction<15>,  Up: Regular expression HOWTO

9.10.2 Simple patterns
----------------------

We’ll start by learning about the simplest possible regular expressions.
Since regular expressions are used to operate on strings, we’ll begin
with the most common task: matching characters.

For a detailed explanation of the computer science underlying regular
expressions (deterministic and non-deterministic finite automata), you
can refer to almost any textbook on writing compilers.

* Menu:

* Matching characters::
* Repeating things::


File: python.info,  Node: Matching characters,  Next: Repeating things,  Up: Simple patterns

9.10.2.1 Matching characters
............................

Most letters and characters will simply match themselves.  For example,
the regular expression ‘test’ will match the string ‘test’ exactly.
(You can enable a case-insensitive mode that would let this RE match
‘Test’ or ‘TEST’ as well; more about this later.)

There are exceptions to this rule; some characters are special
'metacharacters', and don’t match themselves.  Instead, they signal that
some out-of-the-ordinary thing should be matched, or they affect other
portions of the RE by repeating them or changing their meaning.  Much of
this document is devoted to discussing various metacharacters and what
they do.

Here’s a complete list of the metacharacters; their meanings will be
discussed in the rest of this HOWTO.

     . ^ $ * + ? { } [ ] \ | ( )

The first metacharacters we’ll look at are ‘[’ and ‘]’.  They’re used
for specifying a character class, which is a set of characters that you
wish to match.  Characters can be listed individually, or a range of
characters can be indicated by giving two characters and separating them
by a ‘'-'’.  For example, ‘[abc]’ will match any of the characters ‘a’,
‘b’, or ‘c’; this is the same as ‘[a-c]’, which uses a range to express
the same set of characters.  If you wanted to match only lowercase
letters, your RE would be ‘[a-z]’.

Metacharacters (except ‘\’) are not active inside classes.  For example,
‘[akm$]’ will match any of the characters ‘'a'’, ‘'k'’, ‘'m'’, or ‘'$'’;
‘'$'’ is usually a metacharacter, but inside a character class it’s
stripped of its special nature.

You can match the characters not listed within the class by
'complementing' the set.  This is indicated by including a ‘'^'’ as the
first character of the class.  For example, ‘[^5]’ will match any
character except ‘'5'’.  If the caret appears elsewhere in a character
class, it does not have special meaning.  For example: ‘[5^]’ will match
either a ‘'5'’ or a ‘'^'’.

Perhaps the most important metacharacter is the backslash, ‘\’.  As in
Python string literals, the backslash can be followed by various
characters to signal various special sequences.  It’s also used to
escape all the metacharacters so you can still match them in patterns;
for example, if you need to match a ‘[’ or ‘\’, you can precede them
with a backslash to remove their special meaning: ‘\[’ or ‘\\’.

Some of the special sequences beginning with ‘'\'’ represent predefined
sets of characters that are often useful, such as the set of digits, the
set of letters, or the set of anything that isn’t whitespace.

Let’s take an example: ‘\w’ matches any alphanumeric character.  If the
regex pattern is expressed in bytes, this is equivalent to the class
‘[a-zA-Z0-9_]’.  If the regex pattern is a string, ‘\w’ will match all
the characters marked as letters in the Unicode database provided by the
*note unicodedata: 105. module.  You can use the more restricted
definition of ‘\w’ in a string pattern by supplying the *note re.ASCII:
62f. flag when compiling the regular expression.

The following list of special sequences isn’t complete.  For a complete
list of sequences and expanded class definitions for Unicode string
patterns, see the last part of *note Regular Expression Syntax: 727. in
the Standard Library reference.  In general, the Unicode versions match
any character that’s in the appropriate category in the Unicode
database.

‘\d’

     Matches any decimal digit; this is equivalent to the class ‘[0-9]’.

‘\D’

     Matches any non-digit character; this is equivalent to the class
     ‘[^0-9]’.

‘\s’

     Matches any whitespace character; this is equivalent to the class
     ‘[ \t\n\r\f\v]’.

‘\S’

     Matches any non-whitespace character; this is equivalent to the
     class ‘[^ \t\n\r\f\v]’.

‘\w’

     Matches any alphanumeric character; this is equivalent to the class
     ‘[a-zA-Z0-9_]’.

‘\W’

     Matches any non-alphanumeric character; this is equivalent to the
     class ‘[^a-zA-Z0-9_]’.

These sequences can be included inside a character class.  For example,
‘[\s,.]’ is a character class that will match any whitespace character,
or ‘','’ or ‘'.'’.

The final metacharacter in this section is ‘.’.  It matches anything
except a newline character, and there’s an alternate mode (*note
re.DOTALL: 24a8.) where it will match even a newline.  ‘.’ is often used
where you want to match “any character”.


File: python.info,  Node: Repeating things,  Prev: Matching characters,  Up: Simple patterns

9.10.2.2 Repeating things
.........................

Being able to match varying sets of characters is the first thing
regular expressions can do that isn’t already possible with the methods
available on strings.  However, if that was the only additional
capability of regexes, they wouldn’t be much of an advance.  Another
capability is that you can specify that portions of the RE must be
repeated a certain number of times.

The first metacharacter for repeating things that we’ll look at is ‘*’.
‘*’ doesn’t match the literal character ‘'*'’; instead, it specifies
that the previous character can be matched zero or more times, instead
of exactly once.

For example, ‘ca*t’ will match ‘'ct'’ (0 ‘'a'’ characters), ‘'cat'’ (1
‘'a'’), ‘'caaat'’ (3 ‘'a'’ characters), and so forth.

Repetitions such as ‘*’ are 'greedy'; when repeating a RE, the matching
engine will try to repeat it as many times as possible.  If later
portions of the pattern don’t match, the matching engine will then back
up and try again with fewer repetitions.

A step-by-step example will make this more obvious.  Let’s consider the
expression ‘a[bcd]*b’.  This matches the letter ‘'a'’, zero or more
letters from the class ‘[bcd]’, and finally ends with a ‘'b'’.  Now
imagine matching this RE against the string ‘'abcbd'’.

Step       Matched         Explanation
                           
-----------------------------------------------------------------
                           
1          ‘a’             The ‘a’ in the RE matches.
                           
                           
2          ‘abcbd’         The engine matches ‘[bcd]*’, going
                           as far as it can, which is to the
                           end of the string.
                           
                           
3          'Failure'       The engine tries to match ‘b’, but
                           the current position is at the end
                           of the string, so it fails.
                           
                           
4          ‘abcb’          Back up, so that ‘[bcd]*’ matches
                           one less character.
                           
                           
5          'Failure'       Try ‘b’ again, but the current
                           position is at the last character,
                           which is a ‘'d'’.
                           
                           
6          ‘abc’           Back up again, so that ‘[bcd]*’ is
                           only matching ‘bc’.
                           
                           
7          ‘abcb’          Try ‘b’ again.  This time the
                           character at the current position
                           is ‘'b'’, so it succeeds.
                           

The end of the RE has now been reached, and it has matched ‘'abcb'’.
This demonstrates how the matching engine goes as far as it can at
first, and if no match is found it will then progressively back up and
retry the rest of the RE again and again.  It will back up until it has
tried zero matches for ‘[bcd]*’, and if that subsequently fails, the
engine will conclude that the string doesn’t match the RE at all.

Another repeating metacharacter is ‘+’, which matches one or more times.
Pay careful attention to the difference between ‘*’ and ‘+’; ‘*’ matches
'zero' or more times, so whatever’s being repeated may not be present at
all, while ‘+’ requires at least 'one' occurrence.  To use a similar
example, ‘ca+t’ will match ‘'cat'’ (1 ‘'a'’), ‘'caaat'’ (3 ‘'a'’s), but
won’t match ‘'ct'’.

There are two more repeating operators or quantifiers.  The question
mark character, ‘?’, matches either once or zero times; you can think of
it as marking something as being optional.  For example, ‘home-?brew’
matches either ‘'homebrew'’ or ‘'home-brew'’.

The most complicated quantifier is ‘{m,n}’, where 'm' and 'n' are
decimal integers.  This quantifier means there must be at least 'm'
repetitions, and at most 'n'.  For example, ‘a/{1,3}b’ will match
‘'a/b'’, ‘'a//b'’, and ‘'a///b'’.  It won’t match ‘'ab'’, which has no
slashes, or ‘'a////b'’, which has four.

You can omit either 'm' or 'n'; in that case, a reasonable value is
assumed for the missing value.  Omitting 'm' is interpreted as a lower
limit of 0, while omitting 'n' results in an upper bound of infinity.

The simplest case ‘{m}’ matches the preceding item exactly 'm' times.
For example, ‘a/{2}b’ will only match ‘'a//b'’.

Readers of a reductionist bent may notice that the three other
quantifiers can all be expressed using this notation.  ‘{0,}’ is the
same as ‘*’, ‘{1,}’ is equivalent to ‘+’, and ‘{0,1}’ is the same as
‘?’.  It’s better to use ‘*’, ‘+’, or ‘?’ when you can, simply because
they’re shorter and easier to read.


File: python.info,  Node: Using regular expressions,  Next: More pattern power,  Prev: Simple patterns,  Up: Regular expression HOWTO

9.10.3 Using regular expressions
--------------------------------

Now that we’ve looked at some simple regular expressions, how do we
actually use them in Python?  The *note re: b9. module provides an
interface to the regular expression engine, allowing you to compile REs
into objects and then perform matches with them.

* Menu:

* Compiling regular expressions::
* The backslash plague::
* Performing matches::
* Module-level functions::
* Compilation flags::


File: python.info,  Node: Compiling regular expressions,  Next: The backslash plague,  Up: Using regular expressions

9.10.3.1 Compiling regular expressions
......................................

Regular expressions are compiled into pattern objects, which have
methods for various operations such as searching for pattern matches or
performing string substitutions.

     >>> import re
     >>> p = re.compile('ab*')
     >>> p
     re.compile('ab*')

*note re.compile(): bf4. also accepts an optional 'flags' argument, used
to enable various special features and syntax variations.  We’ll go over
the available settings later, but for now a single example will do:

     >>> p = re.compile('ab*', re.IGNORECASE)

The RE is passed to *note re.compile(): bf4. as a string.  REs are
handled as strings because regular expressions aren’t part of the core
Python language, and no special syntax was created for expressing them.
(There are applications that don’t need REs at all, so there’s no need
to bloat the language specification by including them.)  Instead, the
*note re: b9. module is simply a C extension module included with
Python, just like the *note socket: cc. or *note zlib: 133. modules.

Putting REs in strings keeps the Python language simpler, but has one
disadvantage which is the topic of the next section.


File: python.info,  Node: The backslash plague,  Next: Performing matches,  Prev: Compiling regular expressions,  Up: Using regular expressions

9.10.3.2 The backslash plague
.............................

As stated earlier, regular expressions use the backslash character
(‘'\'’) to indicate special forms or to allow special characters to be
used without invoking their special meaning.  This conflicts with
Python’s usage of the same character for the same purpose in string
literals.

Let’s say you want to write a RE that matches the string ‘\section’,
which might be found in a LaTeX file.  To figure out what to write in
the program code, start with the desired string to be matched.  Next,
you must escape any backslashes and other metacharacters by preceding
them with a backslash, resulting in the string ‘\\section’.  The
resulting string that must be passed to *note re.compile(): bf4. must be
‘\\section’.  However, to express this as a Python string literal, both
backslashes must be escaped 'again'.

Characters              Stage
                        
-----------------------------------------------------------------------
                        
‘\section’              Text string to be matched
                        
                        
‘\\section’             Escaped backslash for
                        *note re.compile(): bf4.
                        
                        
‘"\\\\section"’         Escaped backslashes for a string literal
                        

In short, to match a literal backslash, one has to write ‘'\\\\'’ as the
RE string, because the regular expression must be ‘\\’, and each
backslash must be expressed as ‘\\’ inside a regular Python string
literal.  In REs that feature backslashes repeatedly, this leads to lots
of repeated backslashes and makes the resulting strings difficult to
understand.

The solution is to use Python’s raw string notation for regular
expressions; backslashes are not handled in any special way in a string
literal prefixed with ‘'r'’, so ‘r"\n"’ is a two-character string
containing ‘'\'’ and ‘'n'’, while ‘"\n"’ is a one-character string
containing a newline.  Regular expressions will often be written in
Python code using this raw string notation.

In addition, special escape sequences that are valid in regular
expressions, but not valid as Python string literals, now result in a
*note SyntaxWarning: 469. and will eventually become a *note
SyntaxError: 18d, which means the sequences will be invalid if raw
string notation or escaping the backslashes isn’t used.

Regular String          Raw string
                        
-----------------------------------------------
                        
‘"ab*"’                 ‘r"ab*"’
                        
                        
‘"\\\\section"’         ‘r"\\section"’
                        
                        
‘"\\w+\\s+\\1"’         ‘r"\w+\s+\1"’
                        


File: python.info,  Node: Performing matches,  Next: Module-level functions,  Prev: The backslash plague,  Up: Using regular expressions

9.10.3.3 Performing matches
...........................

Once you have an object representing a compiled regular expression, what
do you do with it?  Pattern objects have several methods and attributes.
Only the most significant ones will be covered here; consult the *note
re: b9. docs for a complete listing.

Method/Attribute       Purpose
                       
---------------------------------------------------------------------------
                       
‘match()’              Determine if the RE matches at the beginning of
                       the string.
                       
                       
‘search()’             Scan through a string, looking for any location
                       where this RE matches.
                       
                       
‘findall()’            Find all substrings where the RE matches, and
                       return them as a list.
                       
                       
‘finditer()’           Find all substrings where the RE matches, and
                       return them as an *note iterator: 1ac.
                       

*note match(): 24b9. and *note search(): 24ba. return ‘None’ if no match
can be found.  If they’re successful, a *note match object: fc1.
instance is returned, containing information about the match: where it
starts and ends, the substring it matched, and more.

You can learn about this by interactively experimenting with the *note
re: b9. module.

This HOWTO uses the standard Python interpreter for its examples.
First, run the Python interpreter, import the *note re: b9. module, and
compile a RE:

     >>> import re
     >>> p = re.compile('[a-z]+')
     >>> p
     re.compile('[a-z]+')

Now, you can try matching various strings against the RE ‘[a-z]+’.  An
empty string shouldn’t match at all, since ‘+’ means ‘one or more
repetitions’.  *note match(): 24b9. should return ‘None’ in this case,
which will cause the interpreter to print no output.  You can explicitly
print the result of ‘match()’ to make this clear.

     >>> p.match("")
     >>> print(p.match(""))
     None

Now, let’s try it on a string that it should match, such as ‘tempo’.  In
this case, *note match(): 24b9. will return a *note match object: fc1,
so you should store the result in a variable for later use.

     >>> m = p.match('tempo')
     >>> m
     <re.Match object; span=(0, 5), match='tempo'>

Now you can query the *note match object: fc1. for information about the
matching string.  Match object instances also have several methods and
attributes; the most important ones are:

Method/Attribute       Purpose
                       
------------------------------------------------------------------------
                       
‘group()’              Return the string matched by the RE
                       
                       
‘start()’              Return the starting position of the match
                       
                       
‘end()’                Return the ending position of the match
                       
                       
‘span()’               Return a tuple containing the (start, end)
                       positions of the match
                       

Trying these methods will soon clarify their meaning:

     >>> m.group()
     'tempo'
     >>> m.start(), m.end()
     (0, 5)
     >>> m.span()
     (0, 5)

*note group(): 1066. returns the substring that was matched by the RE.
*note start(): 24cc. and *note end(): 24cd. return the starting and
ending index of the match.  *note span(): 24ce. returns both start and
end indexes in a single tuple.  Since the *note match(): 24b9. method
only checks if the RE matches at the start of a string, ‘start()’ will
always be zero.  However, the *note search(): 24ba. method of patterns
scans through the string, so the match may not start at zero in that
case.

     >>> print(p.match('::: message'))
     None
     >>> m = p.search('::: message'); print(m)
     <re.Match object; span=(4, 11), match='message'>
     >>> m.group()
     'message'
     >>> m.span()
     (4, 11)

In actual programs, the most common style is to store the *note match
object: fc1. in a variable, and then check if it was ‘None’.  This
usually looks like:

     p = re.compile( ... )
     m = p.match( 'string goes here' )
     if m:
         print('Match found: ', m.group())
     else:
         print('No match')

Two pattern methods return all of the matches for a pattern.  *note
findall(): 24c0. returns a list of matching strings:

     >>> p = re.compile(r'\d+')
     >>> p.findall('12 drummers drumming, 11 pipers piping, 10 lords a-leaping')
     ['12', '11', '10']

The ‘r’ prefix, making the literal a raw string literal, is needed in
this example because escape sequences in a normal “cooked” string
literal that are not recognized by Python, as opposed to regular
expressions, now result in a *note SyntaxWarning: 469. and will
eventually become a *note SyntaxError: 18d.  See *note The backslash
plague: 5433.

*note findall(): 24c0. has to create the entire list before it can be
returned as the result.  The *note finditer(): 24c1. method returns a
sequence of *note match object: fc1. instances as an *note iterator:
1ac.:

     >>> iterator = p.finditer('12 drummers drumming, 11 ... 10 ...')
     >>> iterator
     <callable_iterator object at 0x...>
     >>> for match in iterator:
     ...     print(match.span())
     ...
     (0, 2)
     (22, 24)
     (29, 31)


File: python.info,  Node: Module-level functions,  Next: Compilation flags,  Prev: Performing matches,  Up: Using regular expressions

9.10.3.4 Module-level functions
...............................

You don’t have to create a pattern object and call its methods; the
*note re: b9. module also provides top-level functions called *note
match(): 1273, *note search(): 1272, *note findall(): 1065, *note sub():
2a3, and so forth.  These functions take the same arguments as the
corresponding pattern method with the RE string added as the first
argument, and still return either ‘None’ or a *note match object: fc1.
instance.

     >>> print(re.match(r'From\s+', 'Fromage amk'))
     None
     >>> re.match(r'From\s+', 'From amk Thu May 14 19:12:10 1998')
     <re.Match object; span=(0, 5), match='From '>

Under the hood, these functions simply create a pattern object for you
and call the appropriate method on it.  They also store the compiled
object in a cache, so future calls using the same RE won’t need to parse
the pattern again and again.

Should you use these module-level functions, or should you get the
pattern and call its methods yourself?  If you’re accessing a regex
within a loop, pre-compiling it will save a few function calls.  Outside
of loops, there’s not much difference thanks to the internal cache.


File: python.info,  Node: Compilation flags,  Prev: Module-level functions,  Up: Using regular expressions

9.10.3.5 Compilation flags
..........................

Compilation flags let you modify some aspects of how regular expressions
work.  Flags are available in the *note re: b9. module under two names,
a long name such as *note IGNORECASE: 1837. and a short, one-letter form
such as *note I: 24ab.  (If you’re familiar with Perl’s pattern
modifiers, the one-letter forms use the same letters; the short form of
*note re.VERBOSE: 24b7. is *note re.X: 24b0, for example.)  Multiple
flags can be specified by bitwise OR-ing them; ‘re.I | re.M’ sets both
the ‘I’ and *note M: 24ad. flags, for example.

Here’s a table of the available flags, followed by a more detailed
explanation of each one.

Flag                                  Meaning
                                      
---------------------------------------------------------------------------------------
                                      
*note ASCII: 62f, *note A: 24aa.      Makes several escapes like ‘\w’, ‘\b’, ‘\s’
                                      and ‘\d’ match only on ASCII characters with
                                      the respective property.
                                      
                                      
*note DOTALL: 24a8, *note S: 24ae.    Make ‘.’ match any character, including
                                      newlines.
                                      
                                      
*note IGNORECASE: 1837,               Do case-insensitive matches.
*note I: 24ab.                        

*note LOCALE: b88, *note L: 24ac.     Do a locale-aware match.
                                      
                                      
*note MULTILINE: 24a9,                Multi-line matching, affecting ‘^’ and ‘$’.
*note M: 24ad.                        

*note VERBOSE: 24b7, *note X: 24b0.   Enable verbose REs, which can be organized
(for ‘extended’)                      more cleanly and understandably.
                                      

 -- Data: re.I

 -- Data: re.IGNORECASE

     Perform case-insensitive matching; character class and literal
     strings will match letters by ignoring case.  For example, ‘[A-Z]’
     will match lowercase letters, too.  Full Unicode matching also
     works unless the *note ASCII: 62f. flag is used to disable
     non-ASCII matches.  When the Unicode patterns ‘[a-z]’ or ‘[A-Z]’
     are used in combination with the *note IGNORECASE: 1837. flag, they
     will match the 52 ASCII letters and 4 additional non-ASCII letters:
     ‘İ’ (U+0130, Latin capital letter I with dot above), ‘ı’ (U+0131,
     Latin small letter dotless i), ‘ſ’ (U+017F, Latin small letter long
     s) and ‘K’ (U+212A, Kelvin sign).  ‘Spam’ will match ‘'Spam'’,
     ‘'spam'’, ‘'spAM'’, or ‘'ſpam'’ (the latter is matched only in
     Unicode mode).  This lowercasing doesn’t take the current locale
     into account; it will if you also set the *note LOCALE: b88. flag.

 -- Data: re.L

 -- Data: re.LOCALE

     Make ‘\w’, ‘\W’, ‘\b’, ‘\B’ and case-insensitive matching dependent
     on the current locale instead of the Unicode database.

     Locales are a feature of the C library intended to help in writing
     programs that take account of language differences.  For example,
     if you’re processing encoded French text, you’d want to be able to
     write ‘\w+’ to match words, but ‘\w’ only matches the character
     class ‘[A-Za-z]’ in bytes patterns; it won’t match bytes
     corresponding to ‘é’ or ‘ç’.  If your system is configured properly
     and a French locale is selected, certain C functions will tell the
     program that the byte corresponding to ‘é’ should also be
     considered a letter.  Setting the *note LOCALE: b88. flag when
     compiling a regular expression will cause the resulting compiled
     object to use these C functions for ‘\w’; this is slower, but also
     enables ‘\w+’ to match French words as you’d expect.  The use of
     this flag is discouraged in Python 3 as the locale mechanism is
     very unreliable, it only handles one “culture” at a time, and it
     only works with 8-bit locales.  Unicode matching is already enabled
     by default in Python 3 for Unicode (str) patterns, and it is able
     to handle different locales/languages.

 -- Data: re.M

 -- Data: re.MULTILINE

     (‘^’ and ‘$’ haven’t been explained yet; they’ll be introduced in
     section *note More metacharacters: 5437.)

     Usually ‘^’ matches only at the beginning of the string, and ‘$’
     matches only at the end of the string and immediately before the
     newline (if any) at the end of the string.  When this flag is
     specified, ‘^’ matches at the beginning of the string and at the
     beginning of each line within the string, immediately following
     each newline.  Similarly, the ‘$’ metacharacter matches either at
     the end of the string and at the end of each line (immediately
     preceding each newline).

 -- Data: re.S

 -- Data: re.DOTALL

     Makes the ‘'.'’ special character match any character at all,
     including a newline; without this flag, ‘'.'’ will match anything
     'except' a newline.

 -- Data: re.A

 -- Data: re.ASCII

     Make ‘\w’, ‘\W’, ‘\b’, ‘\B’, ‘\s’ and ‘\S’ perform ASCII-only
     matching instead of full Unicode matching.  This is only meaningful
     for Unicode patterns, and is ignored for byte patterns.

 -- Data: re.X

 -- Data: re.VERBOSE

     This flag allows you to write regular expressions that are more
     readable by granting you more flexibility in how you can format
     them.  When this flag has been specified, whitespace within the RE
     string is ignored, except when the whitespace is in a character
     class or preceded by an unescaped backslash; this lets you organize
     and indent the RE more clearly.  This flag also lets you put
     comments within a RE that will be ignored by the engine; comments
     are marked by a ‘'#'’ that’s neither in a character class nor
     preceded by an unescaped backslash.

     For example, here’s a RE that uses *note re.VERBOSE: 24b7.; see how
     much easier it is to read?

          charref = re.compile(r"""
           &[#]                # Start of a numeric entity reference
           (
               0[0-7]+         # Octal form
             | [0-9]+          # Decimal form
             | x[0-9a-fA-F]+   # Hexadecimal form
           )
           ;                   # Trailing semicolon
          """, re.VERBOSE)

     Without the verbose setting, the RE would look like this:

          charref = re.compile("&#(0[0-7]+"
                               "|[0-9]+"
                               "|x[0-9a-fA-F]+);")

     In the above example, Python’s automatic concatenation of string
     literals has been used to break up the RE into smaller pieces, but
     it’s still more difficult to understand than the version using
     *note re.VERBOSE: 24b7.


File: python.info,  Node: More pattern power,  Next: Modifying strings,  Prev: Using regular expressions,  Up: Regular expression HOWTO

9.10.4 More pattern power
-------------------------

So far we’ve only covered a part of the features of regular expressions.
In this section, we’ll cover some new metacharacters, and how to use
groups to retrieve portions of the text that was matched.

* Menu:

* More metacharacters::
* Grouping::
* Non-capturing and named groups::
* Lookahead assertions::


File: python.info,  Node: More metacharacters,  Next: Grouping,  Up: More pattern power

9.10.4.1 More metacharacters
............................

There are some metacharacters that we haven’t covered yet.  Most of them
will be covered in this section.

Some of the remaining metacharacters to be discussed are 'zero-width
assertions'.  They don’t cause the engine to advance through the string;
instead, they consume no characters at all, and simply succeed or fail.
For example, ‘\b’ is an assertion that the current position is located
at a word boundary; the position isn’t changed by the ‘\b’ at all.  This
means that zero-width assertions should never be repeated, because if
they match once at a given location, they can obviously be matched an
infinite number of times.

‘|’

     Alternation, or the “or” operator.  If 'A' and 'B' are regular
     expressions, ‘A|B’ will match any string that matches either 'A' or
     'B'. ‘|’ has very low precedence in order to make it work
     reasonably when you’re alternating multi-character strings.
     ‘Crow|Servo’ will match either ‘'Crow'’ or ‘'Servo'’, not ‘'Cro'’,
     a ‘'w'’ or an ‘'S'’, and ‘'ervo'’.

     To match a literal ‘'|'’, use ‘\|’, or enclose it inside a
     character class, as in ‘[|]’.

‘^’

     Matches at the beginning of lines.  Unless the *note MULTILINE:
     24a9. flag has been set, this will only match at the beginning of
     the string.  In ‘MULTILINE’ mode, this also matches immediately
     after each newline within the string.

     For example, if you wish to match the word ‘From’ only at the
     beginning of a line, the RE to use is ‘^From’.

          >>> print(re.search('^From', 'From Here to Eternity'))
          <re.Match object; span=(0, 4), match='From'>
          >>> print(re.search('^From', 'Reciting From Memory'))
          None

     To match a literal ‘'^'’, use ‘\^’.

‘$’

     Matches at the end of a line, which is defined as either the end of
     the string, or any location followed by a newline character.

          >>> print(re.search('}$', '{block}'))
          <re.Match object; span=(6, 7), match='}'>
          >>> print(re.search('}$', '{block} '))
          None
          >>> print(re.search('}$', '{block}\n'))
          <re.Match object; span=(6, 7), match='}'>

     To match a literal ‘'$'’, use ‘\$’ or enclose it inside a character
     class, as in ‘[$]’.

‘\A’

     Matches only at the start of the string.  When not in *note
     MULTILINE: 24a9. mode, ‘\A’ and ‘^’ are effectively the same.  In
     ‘MULTILINE’ mode, they’re different: ‘\A’ still matches only at the
     beginning of the string, but ‘^’ may match at any location inside
     the string that follows a newline character.

‘\Z’

     Matches only at the end of the string.

‘\b’

     Word boundary.  This is a zero-width assertion that matches only at
     the beginning or end of a word.  A word is defined as a sequence of
     alphanumeric characters, so the end of a word is indicated by
     whitespace or a non-alphanumeric character.

     The following example matches ‘class’ only when it’s a complete
     word; it won’t match when it’s contained inside another word.

          >>> p = re.compile(r'\bclass\b')
          >>> print(p.search('no class at all'))
          <re.Match object; span=(3, 8), match='class'>
          >>> print(p.search('the declassified algorithm'))
          None
          >>> print(p.search('one subclass is'))
          None

     There are two subtleties you should remember when using this
     special sequence.  First, this is the worst collision between
     Python’s string literals and regular expression sequences.  In
     Python’s string literals, ‘\b’ is the backspace character, ASCII
     value 8.  If you’re not using raw strings, then Python will convert
     the ‘\b’ to a backspace, and your RE won’t match as you expect it
     to.  The following example looks the same as our previous RE, but
     omits the ‘'r'’ in front of the RE string.

          >>> p = re.compile('\bclass\b')
          >>> print(p.search('no class at all'))
          None
          >>> print(p.search('\b' + 'class' + '\b'))
          <re.Match object; span=(0, 7), match='\x08class\x08'>

     Second, inside a character class, where there’s no use for this
     assertion, ‘\b’ represents the backspace character, for
     compatibility with Python’s string literals.

‘\B’

     Another zero-width assertion, this is the opposite of ‘\b’, only
     matching when the current position is not at a word boundary.


File: python.info,  Node: Grouping,  Next: Non-capturing and named groups,  Prev: More metacharacters,  Up: More pattern power

9.10.4.2 Grouping
.................

Frequently you need to obtain more information than just whether the RE
matched or not.  Regular expressions are often used to dissect strings
by writing a RE divided into several subgroups which match different
components of interest.  For example, an RFC-822 header line is divided
into a header name and a value, separated by a ‘':'’, like this:

     From: author@example.com
     User-Agent: Thunderbird 1.5.0.9 (X11/20061227)
     MIME-Version: 1.0
     To: editor@example.com

This can be handled by writing a regular expression which matches an
entire header line, and has one group which matches the header name, and
another group which matches the header’s value.

Groups are marked by the ‘'('’, ‘')'’ metacharacters.  ‘'('’ and ‘')'’
have much the same meaning as they do in mathematical expressions; they
group together the expressions contained inside them, and you can repeat
the contents of a group with a quantifier, such as ‘*’, ‘+’, ‘?’, or
‘{m,n}’.  For example, ‘(ab)*’ will match zero or more repetitions of
‘ab’.

     >>> p = re.compile('(ab)*')
     >>> print(p.match('ababababab').span())
     (0, 10)

Groups indicated with ‘'('’, ‘')'’ also capture the starting and ending
index of the text that they match; this can be retrieved by passing an
argument to *note group(): 1066, *note start(): 24cc, *note end(): 24cd,
and *note span(): 24ce.  Groups are numbered starting with 0.  Group 0
is always present; it’s the whole RE, so *note match object: fc1.
methods all have group 0 as their default argument.  Later we’ll see how
to express groups that don’t capture the span of text that they match.

     >>> p = re.compile('(a)b')
     >>> m = p.match('ab')
     >>> m.group()
     'ab'
     >>> m.group(0)
     'ab'

Subgroups are numbered from left to right, from 1 upward.  Groups can be
nested; to determine the number, just count the opening parenthesis
characters, going from left to right.

     >>> p = re.compile('(a(b)c)d')
     >>> m = p.match('abcd')
     >>> m.group(0)
     'abcd'
     >>> m.group(1)
     'abc'
     >>> m.group(2)
     'b'

*note group(): 1066. can be passed multiple group numbers at a time, in
which case it will return a tuple containing the corresponding values
for those groups.

     >>> m.group(2,1,2)
     ('b', 'abc', 'b')

The *note groups(): 1067. method returns a tuple containing the strings
for all the subgroups, from 1 up to however many there are.

     >>> m.groups()
     ('abc', 'b')

Backreferences in a pattern allow you to specify that the contents of an
earlier capturing group must also be found at the current location in
the string.  For example, ‘\1’ will succeed if the exact contents of
group 1 can be found at the current position, and fails otherwise.
Remember that Python’s string literals also use a backslash followed by
numbers to allow including arbitrary characters in a string, so be sure
to use a raw string when incorporating backreferences in a RE.

For example, the following RE detects doubled words in a string.

     >>> p = re.compile(r'\b(\w+)\s+\1\b')
     >>> p.search('Paris in the the spring').group()
     'the the'

Backreferences like this aren’t often useful for just searching through
a string — there are few text formats which repeat data in this way —
but you’ll soon find out that they’re 'very' useful when performing
string substitutions.


File: python.info,  Node: Non-capturing and named groups,  Next: Lookahead assertions,  Prev: Grouping,  Up: More pattern power

9.10.4.3 Non-capturing and named groups
.......................................

Elaborate REs may use many groups, both to capture substrings of
interest, and to group and structure the RE itself.  In complex REs, it
becomes difficult to keep track of the group numbers.  There are two
features which help with this problem.  Both of them use a common syntax
for regular expression extensions, so we’ll look at that first.

Perl 5 is well known for its powerful additions to standard regular
expressions.  For these new features the Perl developers couldn’t choose
new single-keystroke metacharacters or new special sequences beginning
with ‘\’ without making Perl’s regular expressions confusingly different
from standard REs.  If they chose ‘&’ as a new metacharacter, for
example, old expressions would be assuming that ‘&’ was a regular
character and wouldn’t have escaped it by writing ‘\&’ or ‘[&]’.

The solution chosen by the Perl developers was to use ‘(?...)’ as the
extension syntax.  ‘?’ immediately after a parenthesis was a syntax
error because the ‘?’ would have nothing to repeat, so this didn’t
introduce any compatibility problems.  The characters immediately after
the ‘?’ indicate what extension is being used, so ‘(?=foo)’ is one thing
(a positive lookahead assertion) and ‘(?:foo)’ is something else (a
non-capturing group containing the subexpression ‘foo’).

Python supports several of Perl’s extensions and adds an extension
syntax to Perl’s extension syntax.  If the first character after the
question mark is a ‘P’, you know that it’s an extension that’s specific
to Python.

Now that we’ve looked at the general extension syntax, we can return to
the features that simplify working with groups in complex REs.

Sometimes you’ll want to use a group to denote a part of a regular
expression, but aren’t interested in retrieving the group’s contents.
You can make this fact explicit by using a non-capturing group:
‘(?:...)’, where you can replace the ‘...’ with any other regular
expression.

     >>> m = re.match("([abc])+", "abc")
     >>> m.groups()
     ('c',)
     >>> m = re.match("(?:[abc])+", "abc")
     >>> m.groups()
     ()

Except for the fact that you can’t retrieve the contents of what the
group matched, a non-capturing group behaves exactly the same as a
capturing group; you can put anything inside it, repeat it with a
repetition metacharacter such as ‘*’, and nest it within other groups
(capturing or non-capturing).  ‘(?:...)’ is particularly useful when
modifying an existing pattern, since you can add new groups without
changing how all the other groups are numbered.  It should be mentioned
that there’s no performance difference in searching between capturing
and non-capturing groups; neither form is any faster than the other.

A more significant feature is named groups: instead of referring to them
by numbers, groups can be referenced by a name.

The syntax for a named group is one of the Python-specific extensions:
‘(?P<name>...)’.  'name' is, obviously, the name of the group.  Named
groups behave exactly like capturing groups, and additionally associate
a name with a group.  The *note match object: fc1. methods that deal
with capturing groups all accept either integers that refer to the group
by number or strings that contain the desired group’s name.  Named
groups are still given numbers, so you can retrieve information about a
group in two ways:

     >>> p = re.compile(r'(?P<word>\b\w+\b)')
     >>> m = p.search( '(((( Lots of punctuation )))' )
     >>> m.group('word')
     'Lots'
     >>> m.group(1)
     'Lots'

Additionally, you can retrieve named groups as a dictionary with *note
groupdict(): 24cb.:

     >>> m = re.match(r'(?P<first>\w+) (?P<last>\w+)', 'Jane Doe')
     >>> m.groupdict()
     {'first': 'Jane', 'last': 'Doe'}

Named groups are handy because they let you use easily remembered names,
instead of having to remember numbers.  Here’s an example RE from the
*note imaplib: 74. module:

     InternalDate = re.compile(r'INTERNALDATE "'
             r'(?P<day>[ 123][0-9])-(?P<mon>[A-Z][a-z][a-z])-'
             r'(?P<year>[0-9][0-9][0-9][0-9])'
             r' (?P<hour>[0-9][0-9]):(?P<min>[0-9][0-9]):(?P<sec>[0-9][0-9])'
             r' (?P<zonen>[-+])(?P<zoneh>[0-9][0-9])(?P<zonem>[0-9][0-9])'
             r'"')

It’s obviously much easier to retrieve ‘m.group('zonem')’, instead of
having to remember to retrieve group 9.

The syntax for backreferences in an expression such as ‘(...)\1’ refers
to the number of the group.  There’s naturally a variant that uses the
group name instead of the number.  This is another Python extension:
‘(?P=name)’ indicates that the contents of the group called 'name'
should again be matched at the current point.  The regular expression
for finding doubled words, ‘\b(\w+)\s+\1\b’ can also be written as
‘\b(?P<word>\w+)\s+(?P=word)\b’:

     >>> p = re.compile(r'\b(?P<word>\w+)\s+(?P=word)\b')
     >>> p.search('Paris in the the spring').group()
     'the the'


File: python.info,  Node: Lookahead assertions,  Prev: Non-capturing and named groups,  Up: More pattern power

9.10.4.4 Lookahead assertions
.............................

Another zero-width assertion is the lookahead assertion.  Lookahead
assertions are available in both positive and negative form, and look
like this:

‘(?=...)’

     Positive lookahead assertion.  This succeeds if the contained
     regular expression, represented here by ‘...’, successfully matches
     at the current location, and fails otherwise.  But, once the
     contained expression has been tried, the matching engine doesn’t
     advance at all; the rest of the pattern is tried right where the
     assertion started.

‘(?!...)’

     Negative lookahead assertion.  This is the opposite of the positive
     assertion; it succeeds if the contained expression 'doesn’t' match
     at the current position in the string.

To make this concrete, let’s look at a case where a lookahead is useful.
Consider a simple pattern to match a filename and split it apart into a
base name and an extension, separated by a ‘.’.  For example, in
‘news.rc’, ‘news’ is the base name, and ‘rc’ is the filename’s
extension.

The pattern to match this is quite simple:

‘.*[.].*$’

Notice that the ‘.’ needs to be treated specially because it’s a
metacharacter, so it’s inside a character class to only match that
specific character.  Also notice the trailing ‘$’; this is added to
ensure that all the rest of the string must be included in the
extension.  This regular expression matches ‘foo.bar’ and ‘autoexec.bat’
and ‘sendmail.cf’ and ‘printers.conf’.

Now, consider complicating the problem a bit; what if you want to match
filenames where the extension is not ‘bat’?  Some incorrect attempts:

‘.*[.][^b].*$’

The first attempt above tries to exclude ‘bat’ by requiring that the
first character of the extension is not a ‘b’.  This is wrong, because
the pattern also doesn’t match ‘foo.bar’.

‘.*[.]([^b]..|.[^a].|..[^t])$’

The expression gets messier when you try to patch up the first solution
by requiring one of the following cases to match: the first character of
the extension isn’t ‘b’; the second character isn’t ‘a’; or the third
character isn’t ‘t’.  This accepts ‘foo.bar’ and rejects ‘autoexec.bat’,
but it requires a three-letter extension and won’t accept a filename
with a two-letter extension such as ‘sendmail.cf’.  We’ll complicate the
pattern again in an effort to fix it.

‘.*[.]([^b].?.?|.[^a]?.?|..?[^t]?)$’

In the third attempt, the second and third letters are all made optional
in order to allow matching extensions shorter than three characters,
such as ‘sendmail.cf’.

The pattern’s getting really complicated now, which makes it hard to
read and understand.  Worse, if the problem changes and you want to
exclude both ‘bat’ and ‘exe’ as extensions, the pattern would get even
more complicated and confusing.

A negative lookahead cuts through all this confusion:

‘.*[.](?!bat$)[^.]*$’

The negative lookahead means: if the expression ‘bat’ doesn’t match at
this point, try the rest of the pattern; if ‘bat$’ does match, the whole
pattern will fail.  The trailing ‘$’ is required to ensure that
something like ‘sample.batch’, where the extension only starts with
‘bat’, will be allowed.  The ‘[^.]*’ makes sure that the pattern works
when there are multiple dots in the filename.

Excluding another filename extension is now easy; simply add it as an
alternative inside the assertion.  The following pattern excludes
filenames that end in either ‘bat’ or ‘exe’:

‘.*[.](?!bat$|exe$)[^.]*$’


File: python.info,  Node: Modifying strings,  Next: Common problems,  Prev: More pattern power,  Up: Regular expression HOWTO

9.10.5 Modifying strings
------------------------

Up to this point, we’ve simply performed searches against a static
string.  Regular expressions are also commonly used to modify strings in
various ways, using the following pattern methods:

Method/Attribute       Purpose
                       
---------------------------------------------------------------------------
                       
‘split()’              Split the string into a list, splitting it
                       wherever the RE matches
                       
                       
‘sub()’                Find all substrings where the RE matches, and
                       replace them with a different string
                       
                       
‘subn()’               Does the same thing as ‘sub()’, but returns the
                       new string and the number of replacements
                       

* Menu:

* Splitting strings::
* Search and replace::


File: python.info,  Node: Splitting strings,  Next: Search and replace,  Up: Modifying strings

9.10.5.1 Splitting strings
..........................

The *note split(): 24bf. method of a pattern splits a string apart
wherever the RE matches, returning a list of the pieces.  It’s similar
to the *note split(): ede. method of strings but provides much more
generality in the delimiters that you can split by; string ‘split()’
only supports splitting by whitespace or by a fixed string.  As you’d
expect, there’s a module-level *note re.split(): 2a2. function, too.

 -- Method: .split (string[, maxsplit=0])

     Split 'string' by the matches of the regular expression.  If
     capturing parentheses are used in the RE, then their contents will
     also be returned as part of the resulting list.  If 'maxsplit' is
     nonzero, at most 'maxsplit' splits are performed.

You can limit the number of splits made, by passing a value for
'maxsplit'.  When 'maxsplit' is nonzero, at most 'maxsplit' splits will
be made, and the remainder of the string is returned as the final
element of the list.  In the following example, the delimiter is any
sequence of non-alphanumeric characters.

     >>> p = re.compile(r'\W+')
     >>> p.split('This is a test, short and sweet, of split().')
     ['This', 'is', 'a', 'test', 'short', 'and', 'sweet', 'of', 'split', '']
     >>> p.split('This is a test, short and sweet, of split().', 3)
     ['This', 'is', 'a', 'test, short and sweet, of split().']

Sometimes you’re not only interested in what the text between delimiters
is, but also need to know what the delimiter was.  If capturing
parentheses are used in the RE, then their values are also returned as
part of the list.  Compare the following calls:

     >>> p = re.compile(r'\W+')
     >>> p2 = re.compile(r'(\W+)')
     >>> p.split('This... is a test.')
     ['This', 'is', 'a', 'test', '']
     >>> p2.split('This... is a test.')
     ['This', '... ', 'is', ' ', 'a', ' ', 'test', '.', '']

The module-level function *note re.split(): 2a2. adds the RE to be used
as the first argument, but is otherwise the same.

     >>> re.split(r'[\W]+', 'Words, words, words.')
     ['Words', 'words', 'words', '']
     >>> re.split(r'([\W]+)', 'Words, words, words.')
     ['Words', ', ', 'words', ', ', 'words', '.', '']
     >>> re.split(r'[\W]+', 'Words, words, words.', 1)
     ['Words', 'words, words.']


File: python.info,  Node: Search and replace,  Prev: Splitting strings,  Up: Modifying strings

9.10.5.2 Search and replace
...........................

Another common task is to find all the matches for a pattern, and
replace them with a different string.  The *note sub(): 24c2. method
takes a replacement value, which can be either a string or a function,
and the string to be processed.

 -- Method: .sub (replacement, string[, count=0])

     Returns the string obtained by replacing the leftmost
     non-overlapping occurrences of the RE in 'string' by the
     replacement 'replacement'.  If the pattern isn’t found, 'string' is
     returned unchanged.

     The optional argument 'count' is the maximum number of pattern
     occurrences to be replaced; 'count' must be a non-negative integer.
     The default value of 0 means to replace all occurrences.

Here’s a simple example of using the *note sub(): 24c2. method.  It
replaces colour names with the word ‘colour’:

     >>> p = re.compile('(blue|white|red)')
     >>> p.sub('colour', 'blue socks and red shoes')
     'colour socks and colour shoes'
     >>> p.sub('colour', 'blue socks and red shoes', count=1)
     'colour socks and red shoes'

The *note subn(): 24c3. method does the same work, but returns a 2-tuple
containing the new string value and the number of replacements that were
performed:

     >>> p = re.compile('(blue|white|red)')
     >>> p.subn('colour', 'blue socks and red shoes')
     ('colour socks and colour shoes', 2)
     >>> p.subn('colour', 'no colours at all')
     ('no colours at all', 0)

Empty matches are replaced only when they’re not adjacent to a previous
empty match.

     >>> p = re.compile('x*')
     >>> p.sub('-', 'abxd')
     '-a-b--d-'

If 'replacement' is a string, any backslash escapes in it are processed.
That is, ‘\n’ is converted to a single newline character, ‘\r’ is
converted to a carriage return, and so forth.  Unknown escapes such as
‘\&’ are left alone.  Backreferences, such as ‘\6’, are replaced with
the substring matched by the corresponding group in the RE. This lets
you incorporate portions of the original text in the resulting
replacement string.

This example matches the word ‘section’ followed by a string enclosed in
‘{’, ‘}’, and changes ‘section’ to ‘subsection’:

     >>> p = re.compile('section{ ( [^}]* ) }', re.VERBOSE)
     >>> p.sub(r'subsection{\1}','section{First} section{second}')
     'subsection{First} subsection{second}'

There’s also a syntax for referring to named groups as defined by the
‘(?P<name>...)’ syntax.  ‘\g<name>’ will use the substring matched by
the group named ‘name’, and ‘\g<number>’ uses the corresponding group
number.  ‘\g<2>’ is therefore equivalent to ‘\2’, but isn’t ambiguous in
a replacement string such as ‘\g<2>0’.  (‘\20’ would be interpreted as a
reference to group 20, not a reference to group 2 followed by the
literal character ‘'0'’.)  The following substitutions are all
equivalent, but use all three variations of the replacement string.

     >>> p = re.compile('section{ (?P<name> [^}]* ) }', re.VERBOSE)
     >>> p.sub(r'subsection{\1}','section{First}')
     'subsection{First}'
     >>> p.sub(r'subsection{\g<1>}','section{First}')
     'subsection{First}'
     >>> p.sub(r'subsection{\g<name>}','section{First}')
     'subsection{First}'

'replacement' can also be a function, which gives you even more control.
If 'replacement' is a function, the function is called for every
non-overlapping occurrence of 'pattern'.  On each call, the function is
passed a *note match object: fc1. argument for the match and can use
this information to compute the desired replacement string and return
it.

In the following example, the replacement function translates decimals
into hexadecimal:

     >>> def hexrepl(match):
     ...     "Return the hex string for a decimal number"
     ...     value = int(match.group())
     ...     return hex(value)
     ...
     >>> p = re.compile(r'\d+')
     >>> p.sub(hexrepl, 'Call 65490 for printing, 49152 for user code.')
     'Call 0xffd2 for printing, 0xc000 for user code.'

When using the module-level *note re.sub(): 2a3. function, the pattern
is passed as the first argument.  The pattern may be provided as an
object or as a string; if you need to specify regular expression flags,
you must either use a pattern object as the first parameter, or use
embedded modifiers in the pattern string, e.g.  ‘sub("(?i)b+", "x",
"bbbb BBBB")’ returns ‘'x x'’.


File: python.info,  Node: Common problems,  Next: Feedback,  Prev: Modifying strings,  Up: Regular expression HOWTO

9.10.6 Common problems
----------------------

Regular expressions are a powerful tool for some applications, but in
some ways their behaviour isn’t intuitive and at times they don’t behave
the way you may expect them to.  This section will point out some of the
most common pitfalls.

* Menu:

* Use string methods::
* match() versus search(): match versus search.
* Greedy versus non-greedy::
* Using re.VERBOSE: Using re VERBOSE.


File: python.info,  Node: Use string methods,  Next: match versus search,  Up: Common problems

9.10.6.1 Use string methods
...........................

Sometimes using the *note re: b9. module is a mistake.  If you’re
matching a fixed string, or a single character class, and you’re not
using any ‘re’ features such as the *note IGNORECASE: 1837. flag, then
the full power of regular expressions may not be required.  Strings have
several methods for performing operations with fixed strings and they’re
usually much faster, because the implementation is a single small C loop
that’s been optimized for the purpose, instead of the large, more
generalized regular expression engine.

One example might be replacing a single fixed string with another one;
for example, you might replace ‘word’ with ‘deed’.  *note re.sub(): 2a3.
seems like the function to use for this, but consider the *note
replace(): 19a. method.  Note that ‘replace()’ will also replace ‘word’
inside words, turning ‘swordfish’ into ‘sdeedfish’, but the naive RE
‘word’ would have done that, too.  (To avoid performing the substitution
on parts of words, the pattern would have to be ‘\bword\b’, in order to
require that ‘word’ have a word boundary on either side.  This takes the
job beyond ‘replace()’’s abilities.)

Another common task is deleting every occurrence of a single character
from a string or replacing it with another single character.  You might
do this with something like ‘re.sub('\n', ' ', S)’, but *note
translate(): 2387. is capable of doing both tasks and will be faster
than any regular expression operation can be.

In short, before turning to the *note re: b9. module, consider whether
your problem can be solved with a faster and simpler string method.


File: python.info,  Node: match versus search,  Next: Greedy versus non-greedy,  Prev: Use string methods,  Up: Common problems

9.10.6.2 match() versus search()
................................

The *note match(): 1273. function only checks if the RE matches at the
beginning of the string while *note search(): 1272. will scan forward
through the string for a match.  It’s important to keep this distinction
in mind.  Remember, ‘match()’ will only report a successful match which
will start at 0; if the match wouldn’t start at zero, ‘match()’ will
'not' report it.

     >>> print(re.match('super', 'superstition').span())
     (0, 5)
     >>> print(re.match('super', 'insuperable'))
     None

On the other hand, *note search(): 1272. will scan forward through the
string, reporting the first match it finds.

     >>> print(re.search('super', 'superstition').span())
     (0, 5)
     >>> print(re.search('super', 'insuperable').span())
     (2, 7)

Sometimes you’ll be tempted to keep using *note re.match(): 1273, and
just add ‘.*’ to the front of your RE. Resist this temptation and use
*note re.search(): 1272. instead.  The regular expression compiler does
some analysis of REs in order to speed up the process of looking for a
match.  One such analysis figures out what the first character of a
match must be; for example, a pattern starting with ‘Crow’ must match
starting with a ‘'C'’.  The analysis lets the engine quickly scan
through the string looking for the starting character, only trying the
full match if a ‘'C'’ is found.

Adding ‘.*’ defeats this optimization, requiring scanning to the end of
the string and then backtracking to find a match for the rest of the RE.
Use *note re.search(): 1272. instead.


File: python.info,  Node: Greedy versus non-greedy,  Next: Using re VERBOSE,  Prev: match versus search,  Up: Common problems

9.10.6.3 Greedy versus non-greedy
.................................

When repeating a regular expression, as in ‘a*’, the resulting action is
to consume as much of the pattern as possible.  This fact often bites
you when you’re trying to match a pair of balanced delimiters, such as
the angle brackets surrounding an HTML tag.  The naive pattern for
matching a single HTML tag doesn’t work because of the greedy nature of
‘.*’.

     >>> s = '<html><head><title>Title</title>'
     >>> len(s)
     32
     >>> print(re.match('<.*>', s).span())
     (0, 32)
     >>> print(re.match('<.*>', s).group())
     <html><head><title>Title</title>

The RE matches the ‘'<'’ in ‘'<html>'’, and the ‘.*’ consumes the rest
of the string.  There’s still more left in the RE, though, and the ‘>’
can’t match at the end of the string, so the regular expression engine
has to backtrack character by character until it finds a match for the
‘>’.  The final match extends from the ‘'<'’ in ‘'<html>'’ to the ‘'>'’
in ‘'</title>'’, which isn’t what you want.

In this case, the solution is to use the non-greedy quantifiers ‘*?’,
‘+?’, ‘??’, or ‘{m,n}?’, which match as 'little' text as possible.  In
the above example, the ‘'>'’ is tried immediately after the first ‘'<'’
matches, and when it fails, the engine advances a character at a time,
retrying the ‘'>'’ at every step.  This produces just the right result:

     >>> print(re.match('<.*?>', s).group())
     <html>

(Note that parsing HTML or XML with regular expressions is painful.
Quick-and-dirty patterns will handle common cases, but HTML and XML have
special cases that will break the obvious regular expression; by the
time you’ve written a regular expression that handles all of the
possible cases, the patterns will be 'very' complicated.  Use an HTML or
XML parser module for such tasks.)


File: python.info,  Node: Using re VERBOSE,  Prev: Greedy versus non-greedy,  Up: Common problems

9.10.6.4 Using re.VERBOSE
.........................

By now you’ve probably noticed that regular expressions are a very
compact notation, but they’re not terribly readable.  REs of moderate
complexity can become lengthy collections of backslashes, parentheses,
and metacharacters, making them difficult to read and understand.

For such REs, specifying the *note re.VERBOSE: 24b7. flag when compiling
the regular expression can be helpful, because it allows you to format
the regular expression more clearly.

The ‘re.VERBOSE’ flag has several effects.  Whitespace in the regular
expression that 'isn’t' inside a character class is ignored.  This means
that an expression such as ‘dog | cat’ is equivalent to the less
readable ‘dog|cat’, but ‘[a b]’ will still match the characters ‘'a'’,
‘'b'’, or a space.  In addition, you can also put comments inside a RE;
comments extend from a ‘#’ character to the next newline.  When used
with triple-quoted strings, this enables REs to be formatted more
neatly:

     pat = re.compile(r"""
      \s*                 # Skip leading whitespace
      (?P<header>[^:]+)   # Header name
      \s* :               # Whitespace, and a colon
      (?P<value>.*?)      # The header's value -- *? used to
                          # lose the following trailing whitespace
      \s*$                # Trailing whitespace to end-of-line
     """, re.VERBOSE)

This is far more readable than:

     pat = re.compile(r"\s*(?P<header>[^:]+)\s*:(?P<value>.*?)\s*$")


File: python.info,  Node: Feedback,  Prev: Common problems,  Up: Regular expression HOWTO

9.10.7 Feedback
---------------

Regular expressions are a complicated topic.  Did this document help you
understand them?  Were there parts that were unclear, or problems you
encountered that weren’t covered here?  If so, please send suggestions
for improvements to the *note issue tracker: 24e.

The most complete book on regular expressions is almost certainly
Jeffrey Friedl’s Mastering Regular Expressions, published by O’Reilly.
Unfortunately, it exclusively concentrates on Perl and Java’s flavours
of regular expressions, and doesn’t contain any Python material at all,
so it won’t be useful as a reference for programming in Python.  (The
first edition covered Python’s now-removed ‘regex’ module, which won’t
help you much.)  Consider checking it out from your library.


File: python.info,  Node: Socket Programming HOWTO,  Next: Sorting Techniques,  Prev: Regular expression HOWTO,  Up: Python HOWTOs

9.11 Socket Programming HOWTO
=============================


Author: Gordon McMillan

Abstract
........

Sockets are used nearly everywhere, but are one of the most severely
misunderstood technologies around.  This is a 10,000 foot overview of
sockets.  It’s not really a tutorial - you’ll still have work to do in
getting things operational.  It doesn’t cover the fine points (and there
are a lot of them), but I hope it will give you enough background to
begin using them decently.

* Menu:

* Sockets::
* Creating a Socket::
* Using a Socket::
* Disconnecting::
* Non-blocking Sockets::


File: python.info,  Node: Sockets,  Next: Creating a Socket,  Up: Socket Programming HOWTO

9.11.1 Sockets
--------------

I’m only going to talk about INET (i.e.  IPv4) sockets, but they account
for at least 99% of the sockets in use.  And I’ll only talk about STREAM
(i.e.  TCP) sockets - unless you really know what you’re doing (in which
case this HOWTO isn’t for you!), you’ll get better behavior and
performance from a STREAM socket than anything else.  I will try to
clear up the mystery of what a socket is, as well as some hints on how
to work with blocking and non-blocking sockets.  But I’ll start by
talking about blocking sockets.  You’ll need to know how they work
before dealing with non-blocking sockets.

Part of the trouble with understanding these things is that “socket” can
mean a number of subtly different things, depending on context.  So
first, let’s make a distinction between a “client” socket - an endpoint
of a conversation, and a “server” socket, which is more like a
switchboard operator.  The client application (your browser, for
example) uses “client” sockets exclusively; the web server it’s talking
to uses both “server” sockets and “client” sockets.

* Menu:

* History::


File: python.info,  Node: History,  Up: Sockets

9.11.1.1 History
................

Of the various forms of IPC (Inter Process Communication), sockets are
by far the most popular.  On any given platform, there are likely to be
other forms of IPC that are faster, but for cross-platform
communication, sockets are about the only game in town.

They were invented in Berkeley as part of the BSD flavor of Unix.  They
spread like wildfire with the internet.  With good reason — the
combination of sockets with INET makes talking to arbitrary machines
around the world unbelievably easy (at least compared to other schemes).


File: python.info,  Node: Creating a Socket,  Next: Using a Socket,  Prev: Sockets,  Up: Socket Programming HOWTO

9.11.2 Creating a Socket
------------------------

Roughly speaking, when you clicked on the link that brought you to this
page, your browser did something like the following:

     # create an INET, STREAMing socket
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     # now connect to the web server on port 80 - the normal http port
     s.connect(("www.python.org", 80))

When the ‘connect’ completes, the socket ‘s’ can be used to send in a
request for the text of the page.  The same socket will read the reply,
and then be destroyed.  That’s right, destroyed.  Client sockets are
normally only used for one exchange (or a small set of sequential
exchanges).

What happens in the web server is a bit more complex.  First, the web
server creates a “server socket”:

     # create an INET, STREAMing socket
     serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     # bind the socket to a public host, and a well-known port
     serversocket.bind((socket.gethostname(), 80))
     # become a server socket
     serversocket.listen(5)

A couple things to notice: we used ‘socket.gethostname()’ so that the
socket would be visible to the outside world.  If we had used
‘s.bind(('localhost', 80))’ or ‘s.bind(('127.0.0.1', 80))’ we would
still have a “server” socket, but one that was only visible within the
same machine.  ‘s.bind(('', 80))’ specifies that the socket is reachable
by any address the machine happens to have.

A second thing to note: low number ports are usually reserved for “well
known” services (HTTP, SNMP etc).  If you’re playing around, use a nice
high number (4 digits).

Finally, the argument to ‘listen’ tells the socket library that we want
it to queue up as many as 5 connect requests (the normal max) before
refusing outside connections.  If the rest of the code is written
properly, that should be plenty.

Now that we have a “server” socket, listening on port 80, we can enter
the mainloop of the web server:

     while True:
         # accept connections from outside
         (clientsocket, address) = serversocket.accept()
         # now do something with the clientsocket
         # in this case, we'll pretend this is a threaded server
         ct = client_thread(clientsocket)
         ct.run()

There’s actually 3 general ways in which this loop could work -
dispatching a thread to handle ‘clientsocket’, create a new process to
handle ‘clientsocket’, or restructure this app to use non-blocking
sockets, and multiplex between our “server” socket and any active
‘clientsocket’s using ‘select’.  More about that later.  The important
thing to understand now is this: this is 'all' a “server” socket does.
It doesn’t send any data.  It doesn’t receive any data.  It just
produces “client” sockets.  Each ‘clientsocket’ is created in response
to some 'other' “client” socket doing a ‘connect()’ to the host and port
we’re bound to.  As soon as we’ve created that ‘clientsocket’, we go
back to listening for more connections.  The two “clients” are free to
chat it up - they are using some dynamically allocated port which will
be recycled when the conversation ends.

* Menu:

* IPC::


File: python.info,  Node: IPC,  Up: Creating a Socket

9.11.2.1 IPC
............

If you need fast IPC between two processes on one machine, you should
look into pipes or shared memory.  If you do decide to use AF_INET
sockets, bind the “server” socket to ‘'localhost'’.  On most platforms,
this will take a shortcut around a couple of layers of network code and
be quite a bit faster.

See also
........

The *note multiprocessing: 94. integrates cross-platform IPC into a
higher-level API.


File: python.info,  Node: Using a Socket,  Next: Disconnecting,  Prev: Creating a Socket,  Up: Socket Programming HOWTO

9.11.3 Using a Socket
---------------------

The first thing to note, is that the web browser’s “client” socket and
the web server’s “client” socket are identical beasts.  That is, this is
a “peer to peer” conversation.  Or to put it another way, 'as the
designer, you will have to decide what the rules of etiquette are for a
conversation'.  Normally, the ‘connect’ing socket starts the
conversation, by sending in a request, or perhaps a signon.  But that’s
a design decision - it’s not a rule of sockets.

Now there are two sets of verbs to use for communication.  You can use
‘send’ and ‘recv’, or you can transform your client socket into a
file-like beast and use ‘read’ and ‘write’.  The latter is the way Java
presents its sockets.  I’m not going to talk about it here, except to
warn you that you need to use ‘flush’ on sockets.  These are buffered
“files”, and a common mistake is to ‘write’ something, and then ‘read’
for a reply.  Without a ‘flush’ in there, you may wait forever for the
reply, because the request may still be in your output buffer.

Now we come to the major stumbling block of sockets - ‘send’ and ‘recv’
operate on the network buffers.  They do not necessarily handle all the
bytes you hand them (or expect from them), because their major focus is
handling the network buffers.  In general, they return when the
associated network buffers have been filled (‘send’) or emptied
(‘recv’).  They then tell you how many bytes they handled.  It is 'your'
responsibility to call them again until your message has been completely
dealt with.

When a ‘recv’ returns 0 bytes, it means the other side has closed (or is
in the process of closing) the connection.  You will not receive any
more data on this connection.  Ever.  You may be able to send data
successfully; I’ll talk more about this later.

A protocol like HTTP uses a socket for only one transfer.  The client
sends a request, then reads a reply.  That’s it.  The socket is
discarded.  This means that a client can detect the end of the reply by
receiving 0 bytes.

But if you plan to reuse your socket for further transfers, you need to
realize that 'there is no' EOT (End of Transfer) 'on a socket.'  I
repeat: if a socket ‘send’ or ‘recv’ returns after handling 0 bytes, the
connection has been broken.  If the connection has 'not' been broken,
you may wait on a ‘recv’ forever, because the socket will 'not' tell you
that there’s nothing more to read (for now).  Now if you think about
that a bit, you’ll come to realize a fundamental truth of sockets:
'messages must either be fixed length' (yuck), 'or be delimited'
(shrug), 'or indicate how long they are' (much better), 'or end by
shutting down the connection'.  The choice is entirely yours, (but some
ways are righter than others).

Assuming you don’t want to end the connection, the simplest solution is
a fixed length message:

     class MySocket:
         """demonstration class only
           - coded for clarity, not efficiency
         """

         def __init__(self, sock=None):
             if sock is None:
                 self.sock = socket.socket(
                                 socket.AF_INET, socket.SOCK_STREAM)
             else:
                 self.sock = sock

         def connect(self, host, port):
             self.sock.connect((host, port))

         def mysend(self, msg):
             totalsent = 0
             while totalsent < MSGLEN:
                 sent = self.sock.send(msg[totalsent:])
                 if sent == 0:
                     raise RuntimeError("socket connection broken")
                 totalsent = totalsent + sent

         def myreceive(self):
             chunks = []
             bytes_recd = 0
             while bytes_recd < MSGLEN:
                 chunk = self.sock.recv(min(MSGLEN - bytes_recd, 2048))
                 if chunk == b'':
                     raise RuntimeError("socket connection broken")
                 chunks.append(chunk)
                 bytes_recd = bytes_recd + len(chunk)
             return b''.join(chunks)

The sending code here is usable for almost any messaging scheme - in
Python you send strings, and you can use ‘len()’ to determine its length
(even if it has embedded ‘\0’ characters).  It’s mostly the receiving
code that gets more complex.  (And in C, it’s not much worse, except you
can’t use ‘strlen’ if the message has embedded ‘\0’s.)

The easiest enhancement is to make the first character of the message an
indicator of message type, and have the type determine the length.  Now
you have two ‘recv’s - the first to get (at least) that first character
so you can look up the length, and the second in a loop to get the rest.
If you decide to go the delimited route, you’ll be receiving in some
arbitrary chunk size, (4096 or 8192 is frequently a good match for
network buffer sizes), and scanning what you’ve received for a
delimiter.

One complication to be aware of: if your conversational protocol allows
multiple messages to be sent back to back (without some kind of reply),
and you pass ‘recv’ an arbitrary chunk size, you may end up reading the
start of a following message.  You’ll need to put that aside and hold
onto it, until it’s needed.

Prefixing the message with its length (say, as 5 numeric characters)
gets more complex, because (believe it or not), you may not get all 5
characters in one ‘recv’.  In playing around, you’ll get away with it;
but in high network loads, your code will very quickly break unless you
use two ‘recv’ loops - the first to determine the length, the second to
get the data part of the message.  Nasty.  This is also when you’ll
discover that ‘send’ does not always manage to get rid of everything in
one pass.  And despite having read this, you will eventually get bit by
it!

In the interests of space, building your character, (and preserving my
competitive position), these enhancements are left as an exercise for
the reader.  Lets move on to cleaning up.

* Menu:

* Binary Data::


File: python.info,  Node: Binary Data,  Up: Using a Socket

9.11.3.1 Binary Data
....................

It is perfectly possible to send binary data over a socket.  The major
problem is that not all machines use the same formats for binary data.
For example, network byte order(1) is big-endian, with the most
significant byte first, so a 16 bit integer with the value ‘1’ would be
the two hex bytes ‘00 01’.  However, most common processors (x86/AMD64,
ARM, RISC-V), are little-endian, with the least significant byte first -
that same ‘1’ would be ‘01 00’.

Socket libraries have calls for converting 16 and 32 bit integers -
‘ntohl, htonl, ntohs, htons’ where “n” means 'network' and “h” means
'host', “s” means 'short' and “l” means 'long'.  Where network order is
host order, these do nothing, but where the machine is byte-reversed,
these swap the bytes around appropriately.

In these days of 64-bit machines, the ASCII representation of binary
data is frequently smaller than the binary representation.  That’s
because a surprising amount of the time, most integers have the value 0,
or maybe 1.  The string ‘"0"’ would be two bytes, while a full 64-bit
integer would be 8.  Of course, this doesn’t fit well with fixed-length
messages.  Decisions, decisions.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Endianness#Networking


File: python.info,  Node: Disconnecting,  Next: Non-blocking Sockets,  Prev: Using a Socket,  Up: Socket Programming HOWTO

9.11.4 Disconnecting
--------------------

Strictly speaking, you’re supposed to use ‘shutdown’ on a socket before
you ‘close’ it.  The ‘shutdown’ is an advisory to the socket at the
other end.  Depending on the argument you pass it, it can mean “I’m not
going to send anymore, but I’ll still listen”, or “I’m not listening,
good riddance!”.  Most socket libraries, however, are so used to
programmers neglecting to use this piece of etiquette that normally a
‘close’ is the same as ‘shutdown(); close()’.  So in most situations, an
explicit ‘shutdown’ is not needed.

One way to use ‘shutdown’ effectively is in an HTTP-like exchange.  The
client sends a request and then does a ‘shutdown(1)’.  This tells the
server “This client is done sending, but can still receive.” The server
can detect “EOF” by a receive of 0 bytes.  It can assume it has the
complete request.  The server sends a reply.  If the ‘send’ completes
successfully then, indeed, the client was still receiving.

Python takes the automatic shutdown a step further, and says that when a
socket is garbage collected, it will automatically do a ‘close’ if it’s
needed.  But relying on this is a very bad habit.  If your socket just
disappears without doing a ‘close’, the socket at the other end may hang
indefinitely, thinking you’re just being slow.  'Please' ‘close’ your
sockets when you’re done.

* Menu:

* When Sockets Die::


File: python.info,  Node: When Sockets Die,  Up: Disconnecting

9.11.4.1 When Sockets Die
.........................

Probably the worst thing about using blocking sockets is what happens
when the other side comes down hard (without doing a ‘close’).  Your
socket is likely to hang.  TCP is a reliable protocol, and it will wait
a long, long time before giving up on a connection.  If you’re using
threads, the entire thread is essentially dead.  There’s not much you
can do about it.  As long as you aren’t doing something dumb, like
holding a lock while doing a blocking read, the thread isn’t really
consuming much in the way of resources.  Do 'not' try to kill the thread
- part of the reason that threads are more efficient than processes is
that they avoid the overhead associated with the automatic recycling of
resources.  In other words, if you do manage to kill the thread, your
whole process is likely to be screwed up.


File: python.info,  Node: Non-blocking Sockets,  Prev: Disconnecting,  Up: Socket Programming HOWTO

9.11.5 Non-blocking Sockets
---------------------------

If you’ve understood the preceding, you already know most of what you
need to know about the mechanics of using sockets.  You’ll still use the
same calls, in much the same ways.  It’s just that, if you do it right,
your app will be almost inside-out.

In Python, you use ‘socket.setblocking(False)’ to make it non-blocking.
In C, it’s more complex, (for one thing, you’ll need to choose between
the BSD flavor ‘O_NONBLOCK’ and the almost indistinguishable POSIX
flavor ‘O_NDELAY’, which is completely different from ‘TCP_NODELAY’),
but it’s the exact same idea.  You do this after creating the socket,
but before using it.  (Actually, if you’re nuts, you can switch back and
forth.)

The major mechanical difference is that ‘send’, ‘recv’, ‘connect’ and
‘accept’ can return without having done anything.  You have (of course)
a number of choices.  You can check return code and error codes and
generally drive yourself crazy.  If you don’t believe me, try it
sometime.  Your app will grow large, buggy and suck CPU. So let’s skip
the brain-dead solutions and do it right.

Use ‘select’.

In C, coding ‘select’ is fairly complex.  In Python, it’s a piece of
cake, but it’s close enough to the C version that if you understand
‘select’ in Python, you’ll have little trouble with it in C:

     ready_to_read, ready_to_write, in_error = \
                    select.select(
                       potential_readers,
                       potential_writers,
                       potential_errs,
                       timeout)

You pass ‘select’ three lists: the first contains all sockets that you
might want to try reading; the second all the sockets you might want to
try writing to, and the last (normally left empty) those that you want
to check for errors.  You should note that a socket can go into more
than one list.  The ‘select’ call is blocking, but you can give it a
timeout.  This is generally a sensible thing to do - give it a nice long
timeout (say a minute) unless you have good reason to do otherwise.

In return, you will get three lists.  They contain the sockets that are
actually readable, writable and in error.  Each of these lists is a
subset (possibly empty) of the corresponding list you passed in.

If a socket is in the output readable list, you can be
as-close-to-certain-as-we-ever-get-in-this-business that a ‘recv’ on
that socket will return 'something'.  Same idea for the writable list.
You’ll be able to send 'something'.  Maybe not all you want to, but
'something' is better than nothing.  (Actually, any reasonably healthy
socket will return as writable - it just means outbound network buffer
space is available.)

If you have a “server” socket, put it in the potential_readers list.  If
it comes out in the readable list, your ‘accept’ will (almost certainly)
work.  If you have created a new socket to ‘connect’ to someone else,
put it in the potential_writers list.  If it shows up in the writable
list, you have a decent chance that it has connected.

Actually, ‘select’ can be handy even with blocking sockets.  It’s one
way of determining whether you will block - the socket returns as
readable when there’s something in the buffers.  However, this still
doesn’t help with the problem of determining whether the other end is
done, or just busy with something else.

'Portability alert': On Unix, ‘select’ works both with the sockets and
files.  Don’t try this on Windows.  On Windows, ‘select’ works with
sockets only.  Also note that in C, many of the more advanced socket
options are done differently on Windows.  In fact, on Windows I usually
use threads (which work very, very well) with my sockets.


File: python.info,  Node: Sorting Techniques,  Next: Unicode HOWTO,  Prev: Socket Programming HOWTO,  Up: Python HOWTOs

9.12 Sorting Techniques
=======================


Author: Andrew Dalke and Raymond Hettinger

Python lists have a built-in *note list.sort(): bee. method that
modifies the list in-place.  There is also a *note sorted(): bed.
built-in function that builds a new sorted list from an iterable.

In this document, we explore the various techniques for sorting data
using Python.

* Menu:

* Sorting Basics::
* Key Functions::
* Operator Module Functions and Partial Function Evaluation::
* Ascending and Descending::
* Sort Stability and Complex Sorts::
* Decorate-Sort-Undecorate::
* Comparison Functions::
* Odds and Ends: Odds and Ends<2>.
* Partial Sorts::


File: python.info,  Node: Sorting Basics,  Next: Key Functions,  Up: Sorting Techniques

9.12.1 Sorting Basics
---------------------

A simple ascending sort is very easy: just call the *note sorted(): bed.
function.  It returns a new sorted list:

     >>> sorted([5, 2, 3, 1, 4])
     [1, 2, 3, 4, 5]

You can also use the *note list.sort(): bee. method.  It modifies the
list in-place (and returns ‘None’ to avoid confusion).  Usually it’s
less convenient than *note sorted(): bed. - but if you don’t need the
original list, it’s slightly more efficient.

     >>> a = [5, 2, 3, 1, 4]
     >>> a.sort()
     >>> a
     [1, 2, 3, 4, 5]

Another difference is that the *note list.sort(): bee. method is only
defined for lists.  In contrast, the *note sorted(): bed. function
accepts any iterable.

     >>> sorted({1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'})
     [1, 2, 3, 4, 5]


File: python.info,  Node: Key Functions,  Next: Operator Module Functions and Partial Function Evaluation,  Prev: Sorting Basics,  Up: Sorting Techniques

9.12.2 Key Functions
--------------------

Both *note list.sort(): bee. and *note sorted(): bed. have a 'key'
parameter to specify a function (or other callable) to be called on each
list element prior to making comparisons.

For example, here’s a case-insensitive string comparison:

     >>> sorted("This is a test string from Andrew".split(), key=str.casefold)
     ['a', 'Andrew', 'from', 'is', 'string', 'test', 'This']

The value of the 'key' parameter should be a function (or other
callable) that takes a single argument and returns a key to use for
sorting purposes.  This technique is fast because the key function is
called exactly once for each input record.

A common pattern is to sort complex objects using some of the object’s
indices as keys.  For example:

     >>> student_tuples = [
     ...     ('john', 'A', 15),
     ...     ('jane', 'B', 12),
     ...     ('dave', 'B', 10),
     ... ]
     >>> sorted(student_tuples, key=lambda student: student[2])   # sort by age
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

The same technique works for objects with named attributes.  For
example:

     >>> class Student:
     ...     def __init__(self, name, grade, age):
     ...         self.name = name
     ...         self.grade = grade
     ...         self.age = age
     ...     def __repr__(self):
     ...         return repr((self.name, self.grade, self.age))

     >>> student_objects = [
     ...     Student('john', 'A', 15),
     ...     Student('jane', 'B', 12),
     ...     Student('dave', 'B', 10),
     ... ]
     >>> sorted(student_objects, key=lambda student: student.age)   # sort by age
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

Objects with named attributes can be made by a regular class as shown
above, or they can be instances of *note dataclass: 1cb. or a *note
named tuple: 651.


File: python.info,  Node: Operator Module Functions and Partial Function Evaluation,  Next: Ascending and Descending,  Prev: Key Functions,  Up: Sorting Techniques

9.12.3 Operator Module Functions and Partial Function Evaluation
----------------------------------------------------------------

The *note key function: e37. patterns shown above are very common, so
Python provides convenience functions to make accessor functions easier
and faster.  The *note operator: 9f. module has *note itemgetter(): a70,
*note attrgetter(): e66, and a *note methodcaller(): e67. function.

Using those functions, the above examples become simpler and faster:

     >>> from operator import itemgetter, attrgetter

     >>> sorted(student_tuples, key=itemgetter(2))
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

     >>> sorted(student_objects, key=attrgetter('age'))
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

The operator module functions allow multiple levels of sorting.  For
example, to sort by 'grade' then by 'age':

     >>> sorted(student_tuples, key=itemgetter(1,2))
     [('john', 'A', 15), ('dave', 'B', 10), ('jane', 'B', 12)]

     >>> sorted(student_objects, key=attrgetter('grade', 'age'))
     [('john', 'A', 15), ('dave', 'B', 10), ('jane', 'B', 12)]

The *note functools: 5f. module provides another helpful tool for making
key-functions.  The *note partial(): 417. function can reduce the
arity(1) of a multi-argument function making it suitable for use as a
key-function.

     >>> from functools import partial
     >>> from unicodedata import normalize

     >>> names = 'Zoë Åbjørn Núñez Élana Zeke Abe Nubia Eloise'.split()

     >>> sorted(names, key=partial(normalize, 'NFD'))
     ['Abe', 'Åbjørn', 'Eloise', 'Élana', 'Nubia', 'Núñez', 'Zeke', 'Zoë']

     >>> sorted(names, key=partial(normalize, 'NFC'))
     ['Abe', 'Eloise', 'Nubia', 'Núñez', 'Zeke', 'Zoë', 'Åbjørn', 'Élana']

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Arity


File: python.info,  Node: Ascending and Descending,  Next: Sort Stability and Complex Sorts,  Prev: Operator Module Functions and Partial Function Evaluation,  Up: Sorting Techniques

9.12.4 Ascending and Descending
-------------------------------

Both *note list.sort(): bee. and *note sorted(): bed. accept a 'reverse'
parameter with a boolean value.  This is used to flag descending sorts.
For example, to get the student data in reverse 'age' order:

     >>> sorted(student_tuples, key=itemgetter(2), reverse=True)
     [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

     >>> sorted(student_objects, key=attrgetter('age'), reverse=True)
     [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]


File: python.info,  Node: Sort Stability and Complex Sorts,  Next: Decorate-Sort-Undecorate,  Prev: Ascending and Descending,  Up: Sorting Techniques

9.12.5 Sort Stability and Complex Sorts
---------------------------------------

Sorts are guaranteed to be stable(1).  That means that when multiple
records have the same key, their original order is preserved.

     >>> data = [('red', 1), ('blue', 1), ('red', 2), ('blue', 2)]
     >>> sorted(data, key=itemgetter(0))
     [('blue', 1), ('blue', 2), ('red', 1), ('red', 2)]

Notice how the two records for 'blue' retain their original order so
that ‘('blue', 1)’ is guaranteed to precede ‘('blue', 2)’.

This wonderful property lets you build complex sorts in a series of
sorting steps.  For example, to sort the student data by descending
'grade' and then ascending 'age', do the 'age' sort first and then sort
again using 'grade':

     >>> s = sorted(student_objects, key=attrgetter('age'))     # sort on secondary key
     >>> sorted(s, key=attrgetter('grade'), reverse=True)       # now sort on primary key, descending
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

This can be abstracted out into a wrapper function that can take a list
and tuples of field and order to sort them on multiple passes.

     >>> def multisort(xs, specs):
     ...     for key, reverse in reversed(specs):
     ...         xs.sort(key=attrgetter(key), reverse=reverse)
     ...     return xs

     >>> multisort(list(student_objects), (('grade', True), ('age', False)))
     [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

The Timsort(2) algorithm used in Python does multiple sorts efficiently
because it can take advantage of any ordering already present in a
dataset.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Sorting_algorithm#Stability

   (2) https://en.wikipedia.org/wiki/Timsort


File: python.info,  Node: Decorate-Sort-Undecorate,  Next: Comparison Functions,  Prev: Sort Stability and Complex Sorts,  Up: Sorting Techniques

9.12.6 Decorate-Sort-Undecorate
-------------------------------

This idiom is called Decorate-Sort-Undecorate after its three steps:

   * First, the initial list is decorated with new values that control
     the sort order.

   * Second, the decorated list is sorted.

   * Finally, the decorations are removed, creating a list that contains
     only the initial values in the new order.

For example, to sort the student data by 'grade' using the DSU approach:

     >>> decorated = [(student.grade, i, student) for i, student in enumerate(student_objects)]
     >>> decorated.sort()
     >>> [student for grade, i, student in decorated]               # undecorate
     [('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10)]

This idiom works because tuples are compared lexicographically; the
first items are compared; if they are the same then the second items are
compared, and so on.

It is not strictly necessary in all cases to include the index 'i' in
the decorated list, but including it gives two benefits:

   * The sort is stable – if two items have the same key, their order
     will be preserved in the sorted list.

   * The original items do not have to be comparable because the
     ordering of the decorated tuples will be determined by at most the
     first two items.  So for example the original list could contain
     complex numbers which cannot be sorted directly.

Another name for this idiom is Schwartzian transform(1), after Randal L.
Schwartz, who popularized it among Perl programmers.

Now that Python sorting provides key-functions, this technique is not
often needed.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Schwartzian_transform


File: python.info,  Node: Comparison Functions,  Next: Odds and Ends<2>,  Prev: Decorate-Sort-Undecorate,  Up: Sorting Techniques

9.12.7 Comparison Functions
---------------------------

Unlike key functions that return an absolute value for sorting, a
comparison function computes the relative ordering for two inputs.

For example, a balance scale(1) compares two samples giving a relative
ordering: lighter, equal, or heavier.  Likewise, a comparison function
such as ‘cmp(a, b)’ will return a negative value for less-than, zero if
the inputs are equal, or a positive value for greater-than.

It is common to encounter comparison functions when translating
algorithms from other languages.  Also, some libraries provide
comparison functions as part of their API. For example, *note
locale.strcoll(): 3fa4. is a comparison function.

To accommodate those situations, Python provides *note
functools.cmp_to_key: 121f. to wrap the comparison function to make it
usable as a key function:

     sorted(words, key=cmp_to_key(strcoll))  # locale-aware sort order

   ---------- Footnotes ----------

   (1) 
https://upload.wikimedia.org/wikipedia/commons/1/17/Balance_à_tabac_1850.JPG


File: python.info,  Node: Odds and Ends<2>,  Next: Partial Sorts,  Prev: Comparison Functions,  Up: Sorting Techniques

9.12.8 Odds and Ends
--------------------

   * For locale aware sorting, use *note locale.strxfrm(): 1614. for a
     key function or *note locale.strcoll(): 3fa4. for a comparison
     function.  This is necessary because “alphabetical” sort orderings
     can vary across cultures even if the underlying alphabet is the
     same.

   * The 'reverse' parameter still maintains sort stability (so that
     records with equal keys retain the original order).  Interestingly,
     that effect can be simulated without the parameter by using the
     builtin *note reversed(): 86c. function twice:

          >>> data = [('red', 1), ('blue', 1), ('red', 2), ('blue', 2)]
          >>> standard_way = sorted(data, key=itemgetter(0), reverse=True)
          >>> double_reversed = list(reversed(sorted(reversed(data), key=itemgetter(0))))
          >>> assert standard_way == double_reversed
          >>> standard_way
          [('red', 1), ('red', 2), ('blue', 1), ('blue', 2)]

   * The sort routines use ‘<’ when making comparisons between two
     objects.  So, it is easy to add a standard sort order to a class by
     defining an *note __lt__(): 12e7. method:

          >>> Student.__lt__ = lambda self, other: self.age < other.age
          >>> sorted(student_objects)
          [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

     However, note that ‘<’ can fall back to using *note __gt__(): 1355.
     if *note __lt__(): 12e7. is not implemented (see *note
     object.__lt__(): 12e7. for details on the mechanics).  To avoid
     surprises, PEP 8(1) recommends that all six comparison methods be
     implemented.  The *note total_ordering(): f7a. decorator is
     provided to make that task easier.

   * Key functions need not depend directly on the objects being sorted.
     A key function can also access external resources.  For instance,
     if the student grades are stored in a dictionary, they can be used
     to sort a separate list of student names:

          >>> students = ['dave', 'john', 'jane']
          >>> newgrades = {'john': 'F', 'jane':'A', 'dave': 'C'}
          >>> sorted(students, key=newgrades.__getitem__)
          ['jane', 'dave', 'john']

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: Partial Sorts,  Prev: Odds and Ends<2>,  Up: Sorting Techniques

9.12.9 Partial Sorts
--------------------

Some applications require only some of the data to be ordered.  The
standard library provides several tools that do less work than a full
sort:

   * *note min(): f3f. and *note max(): f40. return the smallest and
     largest values, respectively.  These functions make a single pass
     over the input data and require almost no auxiliary memory.

   * *note heapq.nsmallest(): 26f4. and *note heapq.nlargest(): 26f3.
     return the 'n' smallest and largest values, respectively.  These
     functions make a single pass over the data keeping only 'n'
     elements in memory at a time.  For values of 'n' that are small
     relative to the number of inputs, these functions make far fewer
     comparisons than a full sort.

   * *note heapq.heappush(): 150b. and *note heapq.heappop(): 150c.
     create and maintain a partially sorted arrangement of data that
     keeps the smallest element at position ‘0’.  These functions are
     suitable for implementing priority queues which are commonly used
     for task scheduling.


File: python.info,  Node: Unicode HOWTO,  Next: HOWTO Fetch Internet Resources Using The urllib Package,  Prev: Sorting Techniques,  Up: Python HOWTOs

9.13 Unicode HOWTO
==================


Release: 1.12

This HOWTO discusses Python’s support for the Unicode specification for
representing textual data, and explains various problems that people
commonly encounter when trying to work with Unicode.

* Menu:

* Introduction to Unicode::
* Python’s Unicode Support::
* Reading and Writing Unicode Data::
* Acknowledgements: Acknowledgements<10>.


File: python.info,  Node: Introduction to Unicode,  Next: Python’s Unicode Support,  Up: Unicode HOWTO

9.13.1 Introduction to Unicode
------------------------------

* Menu:

* Definitions::
* Encodings::
* References: References<3>.


File: python.info,  Node: Definitions,  Next: Encodings,  Up: Introduction to Unicode

9.13.1.1 Definitions
....................

Today’s programs need to be able to handle a wide variety of characters.
Applications are often internationalized to display messages and output
in a variety of user-selectable languages; the same program might need
to output an error message in English, French, Japanese, Hebrew, or
Russian.  Web content can be written in any of these languages and can
also include a variety of emoji symbols.  Python’s string type uses the
Unicode Standard for representing characters, which lets Python programs
work with all these different possible characters.

Unicode (‘https://www.unicode.org/’) is a specification that aims to
list every character used by human languages and give each character its
own unique code.  The Unicode specifications are continually revised and
updated to add new languages and symbols.

A 'character' is the smallest possible component of a text.  ‘A’, ‘B’,
‘C’, etc., are all different characters.  So are ‘È’ and ‘Í’.
Characters vary depending on the language or context you’re talking
about.  For example, there’s a character for “Roman Numeral One”, ‘Ⅰ’,
that’s separate from the uppercase letter ‘I’.  They’ll usually look the
same, but these are two different characters that have different
meanings.

The Unicode standard describes how characters are represented by 'code
points'.  A code point value is an integer in the range 0 to 0x10FFFF
(about 1.1 million values, the actual number assigned(1) is less than
that).  In the standard and in this document, a code point is written
using the notation ‘U+265E’ to mean the character with value ‘0x265e’
(9,822 in decimal).

The Unicode standard contains a lot of tables listing characters and
their corresponding code points:

     0061    'a'; LATIN SMALL LETTER A
     0062    'b'; LATIN SMALL LETTER B
     0063    'c'; LATIN SMALL LETTER C
     ...
     007B    '{'; LEFT CURLY BRACKET
     ...
     2167    'Ⅷ'; ROMAN NUMERAL EIGHT
     2168    'Ⅸ'; ROMAN NUMERAL NINE
     ...
     265E    '♞'; BLACK CHESS KNIGHT
     265F    '♟'; BLACK CHESS PAWN
     ...
     1F600   '😀'; GRINNING FACE
     1F609   '😉'; WINKING FACE
     ...

Strictly, these definitions imply that it’s meaningless to say ‘this is
character ‘U+265E’’.  ‘U+265E’ is a code point, which represents some
particular character; in this case, it represents the character ‘BLACK
CHESS KNIGHT’, ‘♞’.  In informal contexts, this distinction between code
points and characters will sometimes be forgotten.

A character is represented on a screen or on paper by a set of graphical
elements that’s called a 'glyph'.  The glyph for an uppercase A, for
example, is two diagonal strokes and a horizontal stroke, though the
exact details will depend on the font being used.  Most Python code
doesn’t need to worry about glyphs; figuring out the correct glyph to
display is generally the job of a GUI toolkit or a terminal’s font
renderer.

   ---------- Footnotes ----------

   (1) https://www.unicode.org/versions/latest/#Summary


File: python.info,  Node: Encodings,  Next: References<3>,  Prev: Definitions,  Up: Introduction to Unicode

9.13.1.2 Encodings
..................

To summarize the previous section: a Unicode string is a sequence of
code points, which are numbers from 0 through ‘0x10FFFF’ (1,114,111
decimal).  This sequence of code points needs to be represented in
memory as a set of 'code units', and 'code units' are then mapped to
8-bit bytes.  The rules for translating a Unicode string into a sequence
of bytes are called a 'character encoding', or just an 'encoding'.

The first encoding you might think of is using 32-bit integers as the
code unit, and then using the CPU’s representation of 32-bit integers.
In this representation, the string “Python” might look like this:

        P           y           t           h           o           n
     0x50 00 00 00 79 00 00 00 74 00 00 00 68 00 00 00 6f 00 00 00 6e 00 00 00
        0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

This representation is straightforward but using it presents a number of
problems.

  1. It’s not portable; different processors order the bytes
     differently.

  2. It’s very wasteful of space.  In most texts, the majority of the
     code points are less than 127, or less than 255, so a lot of space
     is occupied by ‘0x00’ bytes.  The above string takes 24 bytes
     compared to the 6 bytes needed for an ASCII representation.
     Increased RAM usage doesn’t matter too much (desktop computers have
     gigabytes of RAM, and strings aren’t usually that large), but
     expanding our usage of disk and network bandwidth by a factor of 4
     is intolerable.

  3. It’s not compatible with existing C functions such as ‘strlen()’,
     so a new family of wide string functions would need to be used.

Therefore this encoding isn’t used very much, and people instead choose
other encodings that are more efficient and convenient, such as UTF-8.

UTF-8 is one of the most commonly used encodings, and Python often
defaults to using it.  UTF stands for “Unicode Transformation Format”,
and the ‘8’ means that 8-bit values are used in the encoding.  (There
are also UTF-16 and UTF-32 encodings, but they are less frequently used
than UTF-8.)  UTF-8 uses the following rules:

  1. If the code point is < 128, it’s represented by the corresponding
     byte value.

  2. If the code point is >= 128, it’s turned into a sequence of two,
     three, or four bytes, where each byte of the sequence is between
     128 and 255.

UTF-8 has several convenient properties:

  1. It can handle any Unicode code point.

  2. A Unicode string is turned into a sequence of bytes that contains
     embedded zero bytes only where they represent the null character
     (U+0000).  This means that UTF-8 strings can be processed by C
     functions such as ‘strcpy()’ and sent through protocols that can’t
     handle zero bytes for anything other than end-of-string markers.

  3. A string of ASCII text is also valid UTF-8 text.

  4. UTF-8 is fairly compact; the majority of commonly used characters
     can be represented with one or two bytes.

  5. If bytes are corrupted or lost, it’s possible to determine the
     start of the next UTF-8-encoded code point and resynchronize.  It’s
     also unlikely that random 8-bit data will look like valid UTF-8.

  6. UTF-8 is a byte oriented encoding.  The encoding specifies that
     each character is represented by a specific sequence of one or more
     bytes.  This avoids the byte-ordering issues that can occur with
     integer and word oriented encodings, like UTF-16 and UTF-32, where
     the sequence of bytes varies depending on the hardware on which the
     string was encoded.


File: python.info,  Node: References<3>,  Prev: Encodings,  Up: Introduction to Unicode

9.13.1.3 References
...................

The Unicode Consortium site(1) has character charts, a glossary, and PDF
versions of the Unicode specification.  Be prepared for some difficult
reading.  A chronology(2) of the origin and development of Unicode is
also available on the site.

On the Computerphile Youtube channel, Tom Scott briefly discusses the
history of Unicode and UTF-8(3) (9 minutes 36 seconds).

To help understand the standard, Jukka Korpela has written an
introductory guide(4) to reading the Unicode character tables.

Another good introductory article(5) was written by Joel Spolsky.  If
this introduction didn’t make things clear to you, you should try
reading this alternate article before continuing.

Wikipedia entries are often helpful; see the entries for “character
encoding(6)” and UTF-8(7), for example.

   ---------- Footnotes ----------

   (1) https://www.unicode.org

   (2) https://www.unicode.org/history/

   (3) https://www.youtube.com/watch?v=MijmeoH9LT4

   (4) https://jkorpela.fi/unicode/guide.html

   (5) 
https://www.joelonsoftware.com/2003/10/08/the-absolute-minimum-every-software-developer-absolutely-positively-must-know-about-unicode-and-character-sets-no-excuses/

   (6) https://en.wikipedia.org/wiki/Character_encoding

   (7) https://en.wikipedia.org/wiki/UTF-8


File: python.info,  Node: Python’s Unicode Support,  Next: Reading and Writing Unicode Data,  Prev: Introduction to Unicode,  Up: Unicode HOWTO

9.13.2 Python’s Unicode Support
-------------------------------

Now that you’ve learned the rudiments of Unicode, we can look at
Python’s Unicode features.

* Menu:

* The String Type::
* Converting to Bytes::
* Unicode Literals in Python Source Code::
* Unicode Properties::
* Comparing Strings::
* Unicode Regular Expressions::
* References: References<4>.


File: python.info,  Node: The String Type,  Next: Converting to Bytes,  Up: Python’s Unicode Support

9.13.2.1 The String Type
........................

Since Python 3.0, the language’s *note str: 44f. type contains Unicode
characters, meaning any string created using ‘"unicode rocks!"’,
‘'unicode rocks!'’, or the triple-quoted string syntax is stored as
Unicode.

The default encoding for Python source code is UTF-8, so you can simply
include a Unicode character in a string literal:

     try:
         with open('/tmp/input.txt', 'r') as f:
             ...
     except OSError:
         # 'File not found' error message.
         print("Fichier non trouvé")

Side note: Python 3 also supports using Unicode characters in
identifiers:

     répertoire = "/tmp/records.log"
     with open(répertoire, "w") as f:
         f.write("test\n")

If you can’t enter a particular character in your editor or want to keep
the source code ASCII-only for some reason, you can also use escape
sequences in string literals.  (Depending on your system, you may see
the actual capital-delta glyph instead of a u escape.)

     >>> "\N{GREEK CAPITAL LETTER DELTA}"  # Using the character name
     '\u0394'
     >>> "\u0394"                          # Using a 16-bit hex value
     '\u0394'
     >>> "\U00000394"                      # Using a 32-bit hex value
     '\u0394'

In addition, one can create a string using the *note decode(): 8df.
method of *note bytes: 1c2.  This method takes an 'encoding' argument,
such as ‘UTF-8’, and optionally an 'errors' argument.

The 'errors' argument specifies the response when the input string can’t
be converted according to the encoding’s rules.  Legal values for this
argument are ‘'strict'’ (raise a *note UnicodeDecodeError: a20.
exception), ‘'replace'’ (use ‘U+FFFD’, ‘REPLACEMENT CHARACTER’),
‘'ignore'’ (just leave the character out of the Unicode result), or
‘'backslashreplace'’ (inserts a ‘\xNN’ escape sequence).  The following
examples show the differences:

     >>> b'\x80abc'.decode("utf-8", "strict")
     Traceback (most recent call last):
         ...
     UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 0:
       invalid start byte
     >>> b'\x80abc'.decode("utf-8", "replace")
     '\ufffdabc'
     >>> b'\x80abc'.decode("utf-8", "backslashreplace")
     '\\x80abc'
     >>> b'\x80abc'.decode("utf-8", "ignore")
     'abc'

Encodings are specified as strings containing the encoding’s name.
Python comes with roughly 100 different encodings; see the Python
Library Reference at *note Standard Encodings: de7. for a list.  Some
encodings have multiple names; for example, ‘'latin-1'’, ‘'iso_8859_1'’
and ‘'8859’’ are all synonyms for the same encoding.

One-character Unicode strings can also be created with the *note chr():
1785. built-in function, which takes integers and returns a Unicode
string of length 1 that contains the corresponding code point.  The
reverse operation is the built-in *note ord(): 209f. function that takes
a one-character Unicode string and returns the code point value:

     >>> chr(57344)
     '\ue000'
     >>> ord('\ue000')
     57344


File: python.info,  Node: Converting to Bytes,  Next: Unicode Literals in Python Source Code,  Prev: The String Type,  Up: Python’s Unicode Support

9.13.2.2 Converting to Bytes
............................

The opposite method of *note bytes.decode(): 8df. is *note str.encode():
8de, which returns a *note bytes: 1c2. representation of the Unicode
string, encoded in the requested 'encoding'.

The 'errors' parameter is the same as the parameter of the *note
decode(): 8df. method but supports a few more possible handlers.  As
well as ‘'strict'’, ‘'ignore'’, and ‘'replace'’ (which in this case
inserts a question mark instead of the unencodable character), there is
also ‘'xmlcharrefreplace'’ (inserts an XML character reference),
‘backslashreplace’ (inserts a ‘\uNNNN’ escape sequence) and
‘namereplace’ (inserts a ‘\N{...}’ escape sequence).

The following example shows the different results:

     >>> u = chr(40960) + 'abcd' + chr(1972)
     >>> u.encode('utf-8')
     b'\xea\x80\x80abcd\xde\xb4'
     >>> u.encode('ascii')
     Traceback (most recent call last):
         ...
     UnicodeEncodeError: 'ascii' codec can't encode character '\ua000' in
       position 0: ordinal not in range(128)
     >>> u.encode('ascii', 'ignore')
     b'abcd'
     >>> u.encode('ascii', 'replace')
     b'?abcd?'
     >>> u.encode('ascii', 'xmlcharrefreplace')
     b'&#40960;abcd&#1972;'
     >>> u.encode('ascii', 'backslashreplace')
     b'\\ua000abcd\\u07b4'
     >>> u.encode('ascii', 'namereplace')
     b'\\N{YI SYLLABLE IT}abcd\\u07b4'

The low-level routines for registering and accessing the available
encodings are found in the *note codecs: 1b. module.  Implementing new
encodings also requires understanding the ‘codecs’ module.  However, the
encoding and decoding functions returned by this module are usually more
low-level than is comfortable, and writing new encodings is a
specialized task, so the module won’t be covered in this HOWTO.


File: python.info,  Node: Unicode Literals in Python Source Code,  Next: Unicode Properties,  Prev: Converting to Bytes,  Up: Python’s Unicode Support

9.13.2.3 Unicode Literals in Python Source Code
...............................................

In Python source code, specific Unicode code points can be written using
the ‘\u’ escape sequence, which is followed by four hex digits giving
the code point.  The ‘\U’ escape sequence is similar, but expects eight
hex digits, not four:

     >>> s = "a\xac\u1234\u20ac\U00008000"
     ... #     ^^^^ two-digit hex escape
     ... #         ^^^^^^ four-digit Unicode escape
     ... #                     ^^^^^^^^^^ eight-digit Unicode escape
     >>> [ord(c) for c in s]
     [97, 172, 4660, 8364, 32768]

Using escape sequences for code points greater than 127 is fine in small
doses, but becomes an annoyance if you’re using many accented
characters, as you would in a program with messages in French or some
other accent-using language.  You can also assemble strings using the
*note chr(): 1785. built-in function, but this is even more tedious.

Ideally, you’d want to be able to write literals in your language’s
natural encoding.  You could then edit Python source code with your
favorite editor which would display the accented characters naturally,
and have the right characters used at runtime.

Python supports writing source code in UTF-8 by default, but you can use
almost any encoding if you declare the encoding being used.  This is
done by including a special comment as either the first or second line
of the source file:

     #!/usr/bin/env python
     # -*- coding: latin-1 -*-

     u = 'abcdé'
     print(ord(u[-1]))

The syntax is inspired by Emacs’s notation for specifying variables
local to a file.  Emacs supports many different variables, but Python
only supports ‘coding’.  The ‘-*-’ symbols indicate to Emacs that the
comment is special; they have no significance to Python but are a
convention.  Python looks for ‘coding: name’ or ‘coding=name’ in the
comment.

If you don’t include such a comment, the default encoding used will be
UTF-8 as already mentioned.  See also PEP 263(1) for more information.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0263/


File: python.info,  Node: Unicode Properties,  Next: Comparing Strings,  Prev: Unicode Literals in Python Source Code,  Up: Python’s Unicode Support

9.13.2.4 Unicode Properties
...........................

The Unicode specification includes a database of information about code
points.  For each defined code point, the information includes the
character’s name, its category, the numeric value if applicable (for
characters representing numeric concepts such as the Roman numerals,
fractions such as one-third and four-fifths, etc.).  There are also
display-related properties, such as how to use the code point in
bidirectional text.

The following program displays some information about several
characters, and prints the numeric value of one particular character:

     import unicodedata

     u = chr(233) + chr(0x0bf2) + chr(3972) + chr(6000) + chr(13231)

     for i, c in enumerate(u):
         print(i, '%04x' % ord(c), unicodedata.category(c), end=" ")
         print(unicodedata.name(c))

     # Get numeric value of second character
     print(unicodedata.numeric(u[1]))

When run, this prints:

     0 00e9 Ll LATIN SMALL LETTER E WITH ACUTE
     1 0bf2 No TAMIL NUMBER ONE THOUSAND
     2 0f84 Mn TIBETAN MARK HALANTA
     3 1770 Lo TAGBANWA LETTER SA
     4 33af So SQUARE RAD OVER S SQUARED
     1000.0

The category codes are abbreviations describing the nature of the
character.  These are grouped into categories such as “Letter”,
“Number”, “Punctuation”, or “Symbol”, which in turn are broken up into
subcategories.  To take the codes from the above output, ‘'Ll'’ means
‘Letter, lowercase’, ‘'No'’ means “Number, other”, ‘'Mn'’ is “Mark,
nonspacing”, and ‘'So'’ is “Symbol, other”.  See the General Category
Values section of the Unicode Character Database documentation(1) for a
list of category codes.

   ---------- Footnotes ----------

   (1) https://www.unicode.org/reports/tr44/#General_Category_Values


File: python.info,  Node: Comparing Strings,  Next: Unicode Regular Expressions,  Prev: Unicode Properties,  Up: Python’s Unicode Support

9.13.2.5 Comparing Strings
..........................

Unicode adds some complication to comparing strings, because the same
set of characters can be represented by different sequences of code
points.  For example, a letter like ‘ê’ can be represented as a single
code point U+00EA, or as U+0065 U+0302, which is the code point for ‘e’
followed by a code point for ‘COMBINING CIRCUMFLEX ACCENT’.  These will
produce the same output when printed, but one is a string of length 1
and the other is of length 2.

One tool for a case-insensitive comparison is the *note casefold(): e06.
string method that converts a string to a case-insensitive form
following an algorithm described by the Unicode Standard.  This
algorithm has special handling for characters such as the German letter
‘ß’ (code point U+00DF), which becomes the pair of lowercase letters
‘ss’.

     >>> street = 'Gürzenichstraße'
     >>> street.casefold()
     'gürzenichstrasse'

A second tool is the *note unicodedata: 105. module’s *note normalize():
6d8. function that converts strings to one of several normal forms,
where letters followed by a combining character are replaced with single
characters.  ‘normalize()’ can be used to perform string comparisons
that won’t falsely report inequality if two strings use combining
characters differently:

     import unicodedata

     def compare_strs(s1, s2):
         def NFD(s):
             return unicodedata.normalize('NFD', s)

         return NFD(s1) == NFD(s2)

     single_char = 'ê'
     multiple_chars = '\N{LATIN SMALL LETTER E}\N{COMBINING CIRCUMFLEX ACCENT}'
     print('length of first string=', len(single_char))
     print('length of second string=', len(multiple_chars))
     print(compare_strs(single_char, multiple_chars))

When run, this outputs:

     $ python compare-strs.py
     length of first string= 1
     length of second string= 2
     True

The first argument to the *note normalize(): 6d8. function is a string
giving the desired normalization form, which can be one of ‘NFC’,
‘NFKC’, ‘NFD’, and ‘NFKD’.

The Unicode Standard also specifies how to do caseless comparisons:

     import unicodedata

     def compare_caseless(s1, s2):
         def NFD(s):
             return unicodedata.normalize('NFD', s)

         return NFD(NFD(s1).casefold()) == NFD(NFD(s2).casefold())

     # Example usage
     single_char = 'ê'
     multiple_chars = '\N{LATIN CAPITAL LETTER E}\N{COMBINING CIRCUMFLEX ACCENT}'

     print(compare_caseless(single_char, multiple_chars))

This will print ‘True’.  (Why is ‘NFD()’ invoked twice?  Because there
are a few characters that make *note casefold(): e06. return a
non-normalized string, so the result needs to be normalized again.  See
section 3.13 of the Unicode Standard for a discussion and an example.)


File: python.info,  Node: Unicode Regular Expressions,  Next: References<4>,  Prev: Comparing Strings,  Up: Python’s Unicode Support

9.13.2.6 Unicode Regular Expressions
....................................

The regular expressions supported by the *note re: b9. module can be
provided either as bytes or strings.  Some of the special character
sequences such as ‘\d’ and ‘\w’ have different meanings depending on
whether the pattern is supplied as bytes or a string.  For example, ‘\d’
will match the characters ‘[0-9]’ in bytes but in strings will match any
character that’s in the ‘'Nd'’ category.

The string in this example has the number 57 written in both Thai and
Arabic numerals:

     import re
     p = re.compile(r'\d+')

     s = "Over \u0e55\u0e57 57 flavours"
     m = p.search(s)
     print(repr(m.group()))

When executed, ‘\d+’ will match the Thai numerals and print them out.
If you supply the *note re.ASCII: 62f. flag to *note compile(): bf4,
‘\d+’ will match the substring “57” instead.

Similarly, ‘\w’ matches a wide variety of Unicode characters but only
‘[a-zA-Z0-9_]’ in bytes or if *note re.ASCII: 62f. is supplied, and ‘\s’
will match either Unicode whitespace characters or ‘[ \t\n\r\f\v]’.


File: python.info,  Node: References<4>,  Prev: Unicode Regular Expressions,  Up: Python’s Unicode Support

9.13.2.7 References
...................

Some good alternative discussions of Python’s Unicode support are:

   * Processing Text Files in Python 3(1), by Nick Coghlan.

   * Pragmatic Unicode(2), a PyCon 2012 presentation by Ned Batchelder.

The *note str: 44f. type is described in the Python library reference at
*note Text Sequence Type — str: 1d92.

The documentation for the *note unicodedata: 105. module.

The documentation for the *note codecs: 1b. module.

Marc-André Lemburg gave a presentation titled "Python and Unicode" (PDF
slides)(3) at EuroPython 2002.  The slides are an excellent overview of
the design of Python 2’s Unicode features (where the Unicode string type
is called ‘unicode’ and literals start with ‘u’).

   ---------- Footnotes ----------

   (1) 
https://python-notes.curiousefficiency.org/en/latest/python3/text_file_processing.html

   (2) https://nedbatchelder.com/text/unipain.html

   (3) https://downloads.egenix.com/python/Unicode-EPC2002-Talk.pdf


File: python.info,  Node: Reading and Writing Unicode Data,  Next: Acknowledgements<10>,  Prev: Python’s Unicode Support,  Up: Unicode HOWTO

9.13.3 Reading and Writing Unicode Data
---------------------------------------

Once you’ve written some code that works with Unicode data, the next
problem is input/output.  How do you get Unicode strings into your
program, and how do you convert Unicode into a form suitable for storage
or transmission?

It’s possible that you may not need to do anything depending on your
input sources and output destinations; you should check whether the
libraries used in your application support Unicode natively.  XML
parsers often return Unicode data, for example.  Many relational
databases also support Unicode-valued columns and can return Unicode
values from an SQL query.

Unicode data is usually converted to a particular encoding before it
gets written to disk or sent over a socket.  It’s possible to do all the
work yourself: open a file, read an 8-bit bytes object from it, and
convert the bytes with ‘bytes.decode(encoding)’.  However, the manual
approach is not recommended.

One problem is the multi-byte nature of encodings; one Unicode character
can be represented by several bytes.  If you want to read the file in
arbitrary-sized chunks (say, 1024 or 4096 bytes), you need to write
error-handling code to catch the case where only part of the bytes
encoding a single Unicode character are read at the end of a chunk.  One
solution would be to read the entire file into memory and then perform
the decoding, but that prevents you from working with files that are
extremely large; if you need to read a 2 GiB file, you need 2 GiB of
RAM.  (More, really, since for at least a moment you’d need to have both
the encoded string and its Unicode version in memory.)

The solution would be to use the low-level decoding interface to catch
the case of partial coding sequences.  The work of implementing this has
already been done for you: the built-in *note open(): 51f. function can
return a file-like object that assumes the file’s contents are in a
specified encoding and accepts Unicode parameters for methods such as
*note read(): 1e24. and *note write(): 1e13.  This works through
‘open()’'s 'encoding' and 'errors' parameters which are interpreted just
like those in *note str.encode(): 8de. and *note bytes.decode(): 8df.

Reading Unicode from a file is therefore simple:

     with open('unicode.txt', encoding='utf-8') as f:
         for line in f:
             print(repr(line))

It’s also possible to open files in update mode, allowing both reading
and writing:

     with open('test', encoding='utf-8', mode='w+') as f:
         f.write('\u4500 blah blah blah\n')
         f.seek(0)
         print(repr(f.readline()[:1]))

The Unicode character ‘U+FEFF’ is used as a byte-order mark (BOM), and
is often written as the first character of a file in order to assist
with autodetection of the file’s byte ordering.  Some encodings, such as
UTF-16, expect a BOM to be present at the start of a file; when such an
encoding is used, the BOM will be automatically written as the first
character and will be silently dropped when the file is read.  There are
variants of these encodings, such as ‘utf-16-le’ and ‘utf-16-be’ for
little-endian and big-endian encodings, that specify one particular byte
ordering and don’t skip the BOM.

In some areas, it is also convention to use a “BOM” at the start of
UTF-8 encoded files; the name is misleading since UTF-8 is not
byte-order dependent.  The mark simply announces that the file is
encoded in UTF-8.  For reading such files, use the ‘utf-8-sig’ codec to
automatically skip the mark if present.

* Menu:

* Unicode filenames::
* Tips for Writing Unicode-aware Programs::
* References: References<5>.


File: python.info,  Node: Unicode filenames,  Next: Tips for Writing Unicode-aware Programs,  Up: Reading and Writing Unicode Data

9.13.3.1 Unicode filenames
..........................

Most of the operating systems in common use today support filenames that
contain arbitrary Unicode characters.  Usually this is implemented by
converting the Unicode string into some encoding that varies depending
on the system.  Today Python is converging on using UTF-8: Python on
MacOS has used UTF-8 for several versions, and Python 3.6 switched to
using UTF-8 on Windows as well.  On Unix systems, there will only be a
*note filesystem encoding: 53e.  if you’ve set the ‘LANG’ or ‘LC_CTYPE’
environment variables; if you haven’t, the default encoding is again
UTF-8.

The *note sys.getfilesystemencoding(): c7a. function returns the
encoding to use on your current system, in case you want to do the
encoding manually, but there’s not much reason to bother.  When opening
a file for reading or writing, you can usually just provide the Unicode
string as the filename, and it will be automatically converted to the
right encoding for you:

     filename = 'filename\u4500abc'
     with open(filename, 'w') as f:
         f.write('blah\n')

Functions in the *note os: a1. module such as *note os.stat(): 4a3. will
also accept Unicode filenames.

The *note os.listdir(): 113e. function returns filenames, which raises
an issue: should it return the Unicode version of filenames, or should
it return bytes containing the encoded versions?  ‘os.listdir()’ can do
both, depending on whether you provided the directory path as bytes or a
Unicode string.  If you pass a Unicode string as the path, filenames
will be decoded using the filesystem’s encoding and a list of Unicode
strings will be returned, while passing a byte path will return the
filenames as bytes.  For example, assuming the default *note filesystem
encoding: 53e. is UTF-8, running the following program:

     fn = 'filename\u4500abc'
     f = open(fn, 'w')
     f.close()

     import os
     print(os.listdir(b'.'))
     print(os.listdir('.'))

will produce the following output:

     $ python listdir-test.py
     [b'filename\xe4\x94\x80abc', ...]
     ['filename\u4500abc', ...]

The first list contains UTF-8-encoded filenames, and the second list
contains the Unicode versions.

Note that on most occasions, you should can just stick with using
Unicode with these APIs.  The bytes APIs should only be used on systems
where undecodable file names can be present; that’s pretty much only
Unix systems now.


File: python.info,  Node: Tips for Writing Unicode-aware Programs,  Next: References<5>,  Prev: Unicode filenames,  Up: Reading and Writing Unicode Data

9.13.3.2 Tips for Writing Unicode-aware Programs
................................................

This section provides some suggestions on writing software that deals
with Unicode.

The most important tip is:

     Software should only work with Unicode strings internally, decoding
     the input data as soon as possible and encoding the output only at
     the end.

If you attempt to write processing functions that accept both Unicode
and byte strings, you will find your program vulnerable to bugs wherever
you combine the two different kinds of strings.  There is no automatic
encoding or decoding: if you do e.g.  ‘str + bytes’, a *note TypeError:
2c3. will be raised.

When using data coming from a web browser or some other untrusted
source, a common technique is to check for illegal characters in a
string before using the string in a generated command line or storing it
in a database.  If you’re doing this, be careful to check the decoded
string, not the encoded bytes data; some encodings may have interesting
properties, such as not being bijective or not being fully
ASCII-compatible.  This is especially true if the input data also
specifies the encoding, since the attacker can then choose a clever way
to hide malicious text in the encoded bytestream.

* Menu:

* Converting Between File Encodings::
* Files in an Unknown Encoding::


File: python.info,  Node: Converting Between File Encodings,  Next: Files in an Unknown Encoding,  Up: Tips for Writing Unicode-aware Programs

9.13.3.3 Converting Between File Encodings
..........................................

The *note StreamRecoder: 1b81. class can transparently convert between
encodings, taking a stream that returns data in encoding #1 and behaving
like a stream returning data in encoding #2.

For example, if you have an input file 'f' that’s in Latin-1, you can
wrap it with a *note StreamRecoder: 1b81. to return bytes encoded in
UTF-8:

     new_f = codecs.StreamRecoder(f,
         # en/decoder: used by read() to encode its results and
         # by write() to decode its input.
         codecs.getencoder('utf-8'), codecs.getdecoder('utf-8'),

         # reader/writer: used to read and write to the stream.
         codecs.getreader('latin-1'), codecs.getwriter('latin-1') )


File: python.info,  Node: Files in an Unknown Encoding,  Prev: Converting Between File Encodings,  Up: Tips for Writing Unicode-aware Programs

9.13.3.4 Files in an Unknown Encoding
.....................................

What can you do if you need to make a change to a file, but don’t know
the file’s encoding?  If you know the encoding is ASCII-compatible and
only want to examine or modify the ASCII parts, you can open the file
with the ‘surrogateescape’ error handler:

     with open(fname, 'r', encoding="ascii", errors="surrogateescape") as f:
         data = f.read()

     # make changes to the string 'data'

     with open(fname + '.new', 'w',
               encoding="ascii", errors="surrogateescape") as f:
         f.write(data)

The ‘surrogateescape’ error handler will decode any non-ASCII bytes as
code points in a special range running from U+DC80 to U+DCFF. These code
points will then turn back into the same bytes when the
‘surrogateescape’ error handler is used to encode the data and write it
back out.


File: python.info,  Node: References<5>,  Prev: Tips for Writing Unicode-aware Programs,  Up: Reading and Writing Unicode Data

9.13.3.5 References
...................

One section of Mastering Python 3 Input/Output(1), a PyCon 2010 talk by
David Beazley, discusses text processing and binary data handling.

The PDF slides for Marc-André Lemburg's presentation "Writing
Unicode-aware Applications in Python"(2) discuss questions of character
encodings as well as how to internationalize and localize an
application.  These slides cover Python 2.x only.

The Guts of Unicode in Python(3) is a PyCon 2013 talk by Benjamin
Peterson that discusses the internal Unicode representation in Python
3.3.

   ---------- Footnotes ----------

   (1) https://pyvideo.org/video/289/pycon-2010-mastering-python-3-i-o

   (2) 
https://downloads.egenix.com/python/LSM2005-Developing-Unicode-aware-applications-in-Python.pdf

   (3) https://pyvideo.org/video/1768/the-guts-of-unicode-in-python


File: python.info,  Node: Acknowledgements<10>,  Prev: Reading and Writing Unicode Data,  Up: Unicode HOWTO

9.13.4 Acknowledgements
-----------------------

The initial draft of this document was written by Andrew Kuchling.  It
has since been revised further by Alexander Belopolsky, Georg Brandl,
Andrew Kuchling, and Ezio Melotti.

Thanks to the following people who have noted errors or offered
suggestions on this article: Éric Araujo, Nicholas Bastin, Nick Coghlan,
Marius Gedminas, Kent Johnson, Ken Krugler, Marc-André Lemburg, Martin
von Löwis, Terry J. Reedy, Serhiy Storchaka, Eryk Sun, Chad Whitacre,
Graham Wideman.


File: python.info,  Node: HOWTO Fetch Internet Resources Using The urllib Package,  Next: An introduction to the ipaddress module,  Prev: Unicode HOWTO,  Up: Python HOWTOs

9.14 HOWTO Fetch Internet Resources Using The urllib Package
============================================================


Author: Michael Foord(1)

* Menu:

* Introduction: Introduction<16>.
* Fetching URLs::
* Handling Exceptions: Handling Exceptions<2>.
* info and geturl::
* Openers and Handlers::
* Basic Authentication::
* Proxies::
* Sockets and Layers::
* Footnotes::

   ---------- Footnotes ----------

   (1) https://agileabstractions.com/


File: python.info,  Node: Introduction<16>,  Next: Fetching URLs,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.1 Introduction
-------------------

Related Articles
................

You may also find useful the following article on fetching web resources
with Python:

   * Basic Authentication(1)

          A tutorial on 'Basic Authentication', with examples in Python.

'urllib.request' is a Python module for fetching URLs (Uniform Resource
Locators).  It offers a very simple interface, in the form of the
'urlopen' function.  This is capable of fetching URLs using a variety of
different protocols.  It also offers a slightly more complex interface
for handling common situations - like basic authentication, cookies,
proxies and so on.  These are provided by objects called handlers and
openers.

urllib.request supports fetching URLs for many “URL schemes” (identified
by the string before the ‘":"’ in URL - for example ‘"ftp"’ is the URL
scheme of ‘"ftp://python.org/"’) using their associated network
protocols (e.g.  FTP, HTTP). This tutorial focuses on the most common
case, HTTP.

For straightforward situations 'urlopen' is very easy to use.  But as
soon as you encounter errors or non-trivial cases when opening HTTP
URLs, you will need some understanding of the HyperText Transfer
Protocol.  The most comprehensive and authoritative reference to HTTP is
RFC 2616(2).  This is a technical document and not intended to be easy
to read.  This HOWTO aims to illustrate using 'urllib', with enough
detail about HTTP to help you through.  It is not intended to replace
the *note urllib.request: 10b. docs, but is supplementary to them.

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20201215133350/http://www.voidspace.org.uk/python/articles/authentication.shtml

   (2) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: Fetching URLs,  Next: Handling Exceptions<2>,  Prev: Introduction<16>,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.2 Fetching URLs
--------------------

The simplest way to use urllib.request is as follows:

     import urllib.request
     with urllib.request.urlopen('http://python.org/') as response:
        html = response.read()

If you wish to retrieve a resource via URL and store it in a temporary
location, you can do so via the *note shutil.copyfileobj(): a6b. and
*note tempfile.NamedTemporaryFile(): 4c9. functions:

     import shutil
     import tempfile
     import urllib.request

     with urllib.request.urlopen('http://python.org/') as response:
         with tempfile.NamedTemporaryFile(delete=False) as tmp_file:
             shutil.copyfileobj(response, tmp_file)

     with open(tmp_file.name) as html:
         pass

Many uses of urllib will be that simple (note that instead of an ‘http:’
URL we could have used a URL starting with ‘ftp:’, ‘file:’, etc.).
However, it’s the purpose of this tutorial to explain the more
complicated cases, concentrating on HTTP.

HTTP is based on requests and responses - the client makes requests and
servers send responses.  urllib.request mirrors this with a ‘Request’
object which represents the HTTP request you are making.  In its
simplest form you create a Request object that specifies the URL you
want to fetch.  Calling ‘urlopen’ with this Request object returns a
response object for the URL requested.  This response is a file-like
object, which means you can for example call ‘.read()’ on the response:

     import urllib.request

     req = urllib.request.Request('http://python.org/')
     with urllib.request.urlopen(req) as response:
        the_page = response.read()

Note that urllib.request makes use of the same Request interface to
handle all URL schemes.  For example, you can make an FTP request like
so:

     req = urllib.request.Request('ftp://example.com/')

In the case of HTTP, there are two extra things that Request objects
allow you to do: First, you can pass data to be sent to the server.
Second, you can pass extra information (“metadata”) 'about' the data or
about the request itself, to the server - this information is sent as
HTTP “headers”.  Let’s look at each of these in turn.

* Menu:

* Data::
* Headers::


File: python.info,  Node: Data,  Next: Headers,  Up: Fetching URLs

9.14.2.1 Data
.............

Sometimes you want to send data to a URL (often the URL will refer to a
CGI (Common Gateway Interface) script or other web application).  With
HTTP, this is often done using what’s known as a 'POST' request.  This
is often what your browser does when you submit a HTML form that you
filled in on the web.  Not all POSTs have to come from forms: you can
use a POST to transmit arbitrary data to your own application.  In the
common case of HTML forms, the data needs to be encoded in a standard
way, and then passed to the Request object as the ‘data’ argument.  The
encoding is done using a function from the *note urllib.parse: 10a.
library.

     import urllib.parse
     import urllib.request

     url = 'http://www.someserver.com/cgi-bin/register.cgi'
     values = {'name' : 'Michael Foord',
               'location' : 'Northampton',
               'language' : 'Python' }

     data = urllib.parse.urlencode(values)
     data = data.encode('ascii') # data should be bytes
     req = urllib.request.Request(url, data)
     with urllib.request.urlopen(req) as response:
        the_page = response.read()

Note that other encodings are sometimes required (e.g.  for file upload
from HTML forms - see HTML Specification, Form Submission(1) for more
details).

If you do not pass the ‘data’ argument, urllib uses a 'GET' request.
One way in which GET and POST requests differ is that POST requests
often have “side-effects”: they change the state of the system in some
way (for example by placing an order with the website for a
hundredweight of tinned spam to be delivered to your door).  Though the
HTTP standard makes it clear that POSTs are intended to 'always' cause
side-effects, and GET requests 'never' to cause side-effects, nothing
prevents a GET request from having side-effects, nor a POST requests
from having no side-effects.  Data can also be passed in an HTTP GET
request by encoding it in the URL itself.

This is done as follows:

     >>> import urllib.request
     >>> import urllib.parse
     >>> data = {}
     >>> data['name'] = 'Somebody Here'
     >>> data['location'] = 'Northampton'
     >>> data['language'] = 'Python'
     >>> url_values = urllib.parse.urlencode(data)
     >>> print(url_values)  # The order may differ from below.
     name=Somebody+Here&language=Python&location=Northampton
     >>> url = 'http://www.example.com/example.cgi'
     >>> full_url = url + '?' + url_values
     >>> data = urllib.request.urlopen(full_url)

Notice that the full URL is created by adding a ‘?’ to the URL, followed
by the encoded values.

   ---------- Footnotes ----------

   (1) https://www.w3.org/TR/REC-html40/interact/forms.html#h-17.13


File: python.info,  Node: Headers,  Prev: Data,  Up: Fetching URLs

9.14.2.2 Headers
................

We’ll discuss here one particular HTTP header, to illustrate how to add
headers to your HTTP request.

Some websites (1) dislike being browsed by programs, or send different
versions to different browsers (2).  By default urllib identifies itself
as ‘Python-urllib/x.y’ (where ‘x’ and ‘y’ are the major and minor
version numbers of the Python release, e.g.  ‘Python-urllib/2.5’), which
may confuse the site, or just plain not work.  The way a browser
identifies itself is through the ‘User-Agent’ header (3).  When you
create a Request object you can pass a dictionary of headers in.  The
following example makes the same request as above, but identifies itself
as a version of Internet Explorer (4).

     import urllib.parse
     import urllib.request

     url = 'http://www.someserver.com/cgi-bin/register.cgi'
     user_agent = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64)'
     values = {'name': 'Michael Foord',
               'location': 'Northampton',
               'language': 'Python' }
     headers = {'User-Agent': user_agent}

     data = urllib.parse.urlencode(values)
     data = data.encode('ascii')
     req = urllib.request.Request(url, data, headers)
     with urllib.request.urlopen(req) as response:
        the_page = response.read()

The response also has two useful methods.  See the section on *note info
and geturl: 547b. which comes after we have a look at what happens when
things go wrong.

   ---------- Footnotes ----------

   (1) Google for example.

   (2) Browser sniffing is a very bad practice for website design -
building sites using web standards is much more sensible.  Unfortunately
a lot of sites still send different versions to different browsers.

   (3) The user agent for MSIE 6 is '‘Mozilla/4.0 (compatible; MSIE 6.0;
Windows NT 5.1; SV1; .NET CLR 1.1.4322)’'

   (4) For details of more HTTP request headers, see Quick Reference to
HTTP Headers (https://jkorpela.fi/http.html).


File: python.info,  Node: Handling Exceptions<2>,  Next: info and geturl,  Prev: Fetching URLs,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.3 Handling Exceptions
--------------------------

'urlopen' raises *note URLError: 3be6. when it cannot handle a response
(though as usual with Python APIs, built-in exceptions such as *note
ValueError: 202, *note TypeError: 2c3. etc.  may also be raised).

*note HTTPError: 1019. is the subclass of *note URLError: 3be6. raised
in the specific case of HTTP URLs.

The exception classes are exported from the *note urllib.error: 109.
module.

* Menu:

* URLError::
* HTTPError::
* Wrapping it Up::


File: python.info,  Node: URLError,  Next: HTTPError,  Up: Handling Exceptions<2>

9.14.3.1 URLError
.................

Often, URLError is raised because there is no network connection (no
route to the specified server), or the specified server doesn’t exist.
In this case, the exception raised will have a ‘reason’ attribute, which
is a tuple containing an error code and a text error message.

e.g.

     >>> req = urllib.request.Request('http://www.pretend_server.org')
     >>> try: urllib.request.urlopen(req)
     ... except urllib.error.URLError as e:
     ...     print(e.reason)
     ...
     (4, 'getaddrinfo failed')


File: python.info,  Node: HTTPError,  Next: Wrapping it Up,  Prev: URLError,  Up: Handling Exceptions<2>

9.14.3.2 HTTPError
..................

Every HTTP response from the server contains a numeric “status code”.
Sometimes the status code indicates that the server is unable to fulfil
the request.  The default handlers will handle some of these responses
for you (for example, if the response is a “redirection” that requests
the client fetch the document from a different URL, urllib will handle
that for you).  For those it can’t handle, urlopen will raise an *note
HTTPError: 1019.  Typical errors include ‘404’ (page not found), ‘403’
(request forbidden), and ‘401’ (authentication required).

See section 10 of RFC 2616(1) for a reference on all the HTTP error
codes.

The *note HTTPError: 1019. instance raised will have an integer ‘code’
attribute, which corresponds to the error sent by the server.

* Menu:

* Error Codes::

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: Error Codes,  Up: HTTPError

9.14.3.3 Error Codes
....................

Because the default handlers handle redirects (codes in the 300 range),
and codes in the 100–299 range indicate success, you will usually only
see error codes in the 400–599 range.

*note http.server.BaseHTTPRequestHandler.responses: 3c85. is a useful
dictionary of response codes that shows all the response codes used by
RFC 2616(1).  An excerpt from the dictionary is shown below

     responses = {
         ...
         <HTTPStatus.OK: 200>: ('OK', 'Request fulfilled, document follows'),
         ...
         <HTTPStatus.FORBIDDEN: 403>: ('Forbidden',
                                       'Request forbidden -- authorization will '
                                       'not help'),
         <HTTPStatus.NOT_FOUND: 404>: ('Not Found',
                                       'Nothing matches the given URI'),
         ...
         <HTTPStatus.IM_A_TEAPOT: 418>: ("I'm a Teapot",
                                         'Server refuses to brew coffee because '
                                         'it is a teapot'),
         ...
         <HTTPStatus.SERVICE_UNAVAILABLE: 503>: ('Service Unavailable',
                                                 'The server cannot process the '
                                                 'request due to a high load'),
         ...
         }

When an error is raised the server responds by returning an HTTP error
code 'and' an error page.  You can use the *note HTTPError: 1019.
instance as a response on the page returned.  This means that as well as
the code attribute, it also has read, geturl, and info, methods as
returned by the ‘urllib.response’ module:

     >>> req = urllib.request.Request('http://www.python.org/fish.html')
     >>> try:
     ...     urllib.request.urlopen(req)
     ... except urllib.error.HTTPError as e:
     ...     print(e.code)
     ...     print(e.read())
     ...
     404
     b'<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">\n\n\n<html
       ...
       <title>Page Not Found</title>\n
       ...

   ---------- Footnotes ----------

   (1) https://datatracker.ietf.org/doc/html/rfc2616.html


File: python.info,  Node: Wrapping it Up,  Prev: HTTPError,  Up: Handling Exceptions<2>

9.14.3.4 Wrapping it Up
.......................

So if you want to be prepared for *note HTTPError: 1019. 'or' *note
URLError: 3be6. there are two basic approaches.  I prefer the second
approach.

* Menu:

* Number 1::
* Number 2::


File: python.info,  Node: Number 1,  Next: Number 2,  Up: Wrapping it Up

9.14.3.5 Number 1
.................

     from urllib.request import Request, urlopen
     from urllib.error import URLError, HTTPError
     req = Request(someurl)
     try:
         response = urlopen(req)
     except HTTPError as e:
         print('The server couldn\'t fulfill the request.')
         print('Error code: ', e.code)
     except URLError as e:
         print('We failed to reach a server.')
         print('Reason: ', e.reason)
     else:
         # everything is fine

     Note: The ‘except HTTPError’ 'must' come first, otherwise ‘except
     URLError’ will 'also' catch an *note HTTPError: 1019.


File: python.info,  Node: Number 2,  Prev: Number 1,  Up: Wrapping it Up

9.14.3.6 Number 2
.................

     from urllib.request import Request, urlopen
     from urllib.error import URLError
     req = Request(someurl)
     try:
         response = urlopen(req)
     except URLError as e:
         if hasattr(e, 'reason'):
             print('We failed to reach a server.')
             print('Reason: ', e.reason)
         elif hasattr(e, 'code'):
             print('The server couldn\'t fulfill the request.')
             print('Error code: ', e.code)
     else:
         # everything is fine


File: python.info,  Node: info and geturl,  Next: Openers and Handlers,  Prev: Handling Exceptions<2>,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.4 info and geturl
----------------------

The response returned by urlopen (or the *note HTTPError: 1019.
instance) has two useful methods ‘info()’ and ‘geturl()’ and is defined
in the module *note urllib.response: 10c.

   * 'geturl' - this returns the real URL of the page fetched.  This is
     useful because ‘urlopen’ (or the opener object used) may have
     followed a redirect.  The URL of the page fetched may not be the
     same as the URL requested.

   * 'info' - this returns a dictionary-like object that describes the
     page fetched, particularly the headers sent by the server.  It is
     currently an *note http.client.HTTPMessage: 3c9f. instance.

Typical headers include ‘Content-length’, ‘Content-type’, and so on.
See the Quick Reference to HTTP Headers(1) for a useful listing of HTTP
headers with brief explanations of their meaning and use.

   ---------- Footnotes ----------

   (1) https://jkorpela.fi/http.html


File: python.info,  Node: Openers and Handlers,  Next: Basic Authentication,  Prev: info and geturl,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.5 Openers and Handlers
---------------------------

When you fetch a URL you use an opener (an instance of the perhaps
confusingly named *note urllib.request.OpenerDirector: 3be7.).  Normally
we have been using the default opener - via ‘urlopen’ - but you can
create custom openers.  Openers use handlers.  All the “heavy lifting”
is done by the handlers.  Each handler knows how to open URLs for a
particular URL scheme (http, ftp, etc.), or how to handle an aspect of
URL opening, for example HTTP redirections or HTTP cookies.

You will want to create openers if you want to fetch URLs with specific
handlers installed, for example to get an opener that handles cookies,
or to get an opener that does not handle redirections.

To create an opener, instantiate an ‘OpenerDirector’, and then call
‘.add_handler(some_handler_instance)’ repeatedly.

Alternatively, you can use ‘build_opener’, which is a convenience
function for creating opener objects with a single function call.
‘build_opener’ adds several handlers by default, but provides a quick
way to add more and/or override the default handlers.

Other sorts of handlers you might want to can handle proxies,
authentication, and other common but slightly specialised situations.

‘install_opener’ can be used to make an ‘opener’ object the (global)
default opener.  This means that calls to ‘urlopen’ will use the opener
you have installed.

Opener objects have an ‘open’ method, which can be called directly to
fetch urls in the same way as the ‘urlopen’ function: there’s no need to
call ‘install_opener’, except as a convenience.


File: python.info,  Node: Basic Authentication,  Next: Proxies,  Prev: Openers and Handlers,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.6 Basic Authentication
---------------------------

To illustrate creating and installing a handler we will use the
‘HTTPBasicAuthHandler’.  For a more detailed discussion of this subject
– including an explanation of how Basic Authentication works - see the
Basic Authentication Tutorial(1).

When authentication is required, the server sends a header (as well as
the 401 error code) requesting authentication.  This specifies the
authentication scheme and a ‘realm’.  The header looks like:
‘WWW-Authenticate: SCHEME realm="REALM"’.

e.g.

     WWW-Authenticate: Basic realm="cPanel Users"

The client should then retry the request with the appropriate name and
password for the realm included as a header in the request.  This is
‘basic authentication’.  In order to simplify this process we can create
an instance of ‘HTTPBasicAuthHandler’ and an opener to use this handler.

The ‘HTTPBasicAuthHandler’ uses an object called a password manager to
handle the mapping of URLs and realms to passwords and usernames.  If
you know what the realm is (from the authentication header sent by the
server), then you can use a ‘HTTPPasswordMgr’.  Frequently one doesn’t
care what the realm is.  In that case, it is convenient to use
‘HTTPPasswordMgrWithDefaultRealm’.  This allows you to specify a default
username and password for a URL. This will be supplied in the absence of
you providing an alternative combination for a specific realm.  We
indicate this by providing ‘None’ as the realm argument to the
‘add_password’ method.

The top-level URL is the first URL that requires authentication.  URLs
“deeper” than the URL you pass to .add_password() will also match.

     # create a password manager
     password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()

     # Add the username and password.
     # If we knew the realm, we could use it instead of None.
     top_level_url = "http://example.com/foo/"
     password_mgr.add_password(None, top_level_url, username, password)

     handler = urllib.request.HTTPBasicAuthHandler(password_mgr)

     # create "opener" (OpenerDirector instance)
     opener = urllib.request.build_opener(handler)

     # use the opener to fetch a URL
     opener.open(a_url)

     # Install the opener.
     # Now all calls to urllib.request.urlopen use our opener.
     urllib.request.install_opener(opener)

     Note: In the above example we only supplied our
     ‘HTTPBasicAuthHandler’ to ‘build_opener’.  By default openers have
     the handlers for normal situations – ‘ProxyHandler’ (if a proxy
     setting such as an ‘http_proxy’ environment variable is set),
     ‘UnknownHandler’, ‘HTTPHandler’, ‘HTTPDefaultErrorHandler’,
     ‘HTTPRedirectHandler’, ‘FTPHandler’, ‘FileHandler’, ‘DataHandler’,
     ‘HTTPErrorProcessor’.

‘top_level_url’ is in fact 'either' a full URL (including the ‘http:’
scheme component and the hostname and optionally the port number) e.g.
‘"http://example.com/"’ 'or' an “authority” (i.e.  the hostname,
optionally including the port number) e.g.  ‘"example.com"’ or
‘"example.com:8080"’ (the latter example includes a port number).  The
authority, if present, must NOT contain the “userinfo” component - for
example ‘"joe:password@example.com"’ is not correct.

   ---------- Footnotes ----------

   (1) 
https://web.archive.org/web/20201215133350/http://www.voidspace.org.uk/python/articles/authentication.shtml


File: python.info,  Node: Proxies,  Next: Sockets and Layers,  Prev: Basic Authentication,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.7 Proxies
--------------

'urllib' will auto-detect your proxy settings and use those.  This is
through the ‘ProxyHandler’, which is part of the normal handler chain
when a proxy setting is detected.  Normally that’s a good thing, but
there are occasions when it may not be helpful (1).  One way to do this
is to setup our own ‘ProxyHandler’, with no proxies defined.  This is
done using similar steps to setting up a *note Basic Authentication:
5484. handler:

     >>> proxy_support = urllib.request.ProxyHandler({})
     >>> opener = urllib.request.build_opener(proxy_support)
     >>> urllib.request.install_opener(opener)

     Note: Currently ‘urllib.request’ 'does not' support fetching of
     ‘https’ locations through a proxy.  However, this can be enabled by
     extending urllib.request as shown in the recipe (2).

     Note: ‘HTTP_PROXY’ will be ignored if a variable ‘REQUEST_METHOD’
     is set; see the documentation on *note getproxies(): 3be3.

   ---------- Footnotes ----------

   (1) In my case I have to use a proxy to access the internet at work.
If you attempt to fetch 'localhost' URLs through this proxy it blocks
them.  IE is set to use the proxy, which urllib picks up on.  In order
to test scripts with a localhost server, I have to prevent urllib from
using the proxy.

   (2) urllib opener for SSL proxy (CONNECT method): ASPN Cookbook
Recipe
(https://code.activestate.com/recipes/456195-urrlib2-opener-for-ssl-proxy-connect-method/).


File: python.info,  Node: Sockets and Layers,  Next: Footnotes,  Prev: Proxies,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.8 Sockets and Layers
-------------------------

The Python support for fetching resources from the web is layered.
urllib uses the *note http.client: 6f. library, which in turn uses the
socket library.

As of Python 2.3 you can specify how long a socket should wait for a
response before timing out.  This can be useful in applications which
have to fetch web pages.  By default the socket module has 'no timeout'
and can hang.  Currently, the socket timeout is not exposed at the
http.client or urllib.request levels.  However, you can set the default
timeout globally for all sockets using

     import socket
     import urllib.request

     # timeout in seconds
     timeout = 10
     socket.setdefaulttimeout(timeout)

     # this call to urllib.request.urlopen now uses the default timeout
     # we have set in the socket module
     req = urllib.request.Request('http://www.voidspace.org.uk')
     response = urllib.request.urlopen(req)

__________________________________________________________________


File: python.info,  Node: Footnotes,  Prev: Sockets and Layers,  Up: HOWTO Fetch Internet Resources Using The urllib Package

9.14.9 Footnotes
----------------

This document was reviewed and revised by John Lee.


File: python.info,  Node: An introduction to the ipaddress module,  Next: Instrumenting CPython with DTrace and SystemTap,  Prev: HOWTO Fetch Internet Resources Using The urllib Package,  Up: Python HOWTOs

9.15 An introduction to the ipaddress module
============================================


author: Peter Moody


author: Nick Coghlan

Overview
........

This document aims to provide a gentle introduction to the *note
ipaddress: 80. module.  It is aimed primarily at users that aren’t
already familiar with IP networking terminology, but may also be useful
to network engineers wanting an overview of how ‘ipaddress’ represents
IP network addressing concepts.

* Menu:

* Creating Address/Network/Interface objects::
* Inspecting Address/Network/Interface Objects::
* Networks as lists of Addresses::
* Comparisons: Comparisons<4>.
* Using IP Addresses with other modules::
* Getting more detail when instance creation fails::


File: python.info,  Node: Creating Address/Network/Interface objects,  Next: Inspecting Address/Network/Interface Objects,  Up: An introduction to the ipaddress module

9.15.1 Creating Address/Network/Interface objects
-------------------------------------------------

Since *note ipaddress: 80. is a module for inspecting and manipulating
IP addresses, the first thing you’ll want to do is create some objects.
You can use ‘ipaddress’ to create objects from strings and integers.

* Menu:

* A Note on IP Versions::
* IP Host Addresses::
* Defining Networks::
* Host Interfaces::


File: python.info,  Node: A Note on IP Versions,  Next: IP Host Addresses,  Up: Creating Address/Network/Interface objects

9.15.1.1 A Note on IP Versions
..............................

For readers that aren’t particularly familiar with IP addressing, it’s
important to know that the Internet Protocol (IP) is currently in the
process of moving from version 4 of the protocol to version 6.  This
transition is occurring largely because version 4 of the protocol
doesn’t provide enough addresses to handle the needs of the whole world,
especially given the increasing number of devices with direct
connections to the internet.

Explaining the details of the differences between the two versions of
the protocol is beyond the scope of this introduction, but readers need
to at least be aware that these two versions exist, and it will
sometimes be necessary to force the use of one version or the other.


File: python.info,  Node: IP Host Addresses,  Next: Defining Networks,  Prev: A Note on IP Versions,  Up: Creating Address/Network/Interface objects

9.15.1.2 IP Host Addresses
..........................

Addresses, often referred to as “host addresses” are the most basic unit
when working with IP addressing.  The simplest way to create addresses
is to use the *note ipaddress.ip_address(): 3e9c. factory function,
which automatically determines whether to create an IPv4 or IPv6 address
based on the passed in value:

     >>> ipaddress.ip_address('192.0.2.1')
     IPv4Address('192.0.2.1')
     >>> ipaddress.ip_address('2001:DB8::1')
     IPv6Address('2001:db8::1')

Addresses can also be created directly from integers.  Values that will
fit within 32 bits are assumed to be IPv4 addresses:

     >>> ipaddress.ip_address(3221225985)
     IPv4Address('192.0.2.1')
     >>> ipaddress.ip_address(42540766411282592856903984951653826561)
     IPv6Address('2001:db8::1')

To force the use of IPv4 or IPv6 addresses, the relevant classes can be
invoked directly.  This is particularly useful to force creation of IPv6
addresses for small integers:

     >>> ipaddress.ip_address(1)
     IPv4Address('0.0.0.1')
     >>> ipaddress.IPv4Address(1)
     IPv4Address('0.0.0.1')
     >>> ipaddress.IPv6Address(1)
     IPv6Address('::1')


File: python.info,  Node: Defining Networks,  Next: Host Interfaces,  Prev: IP Host Addresses,  Up: Creating Address/Network/Interface objects

9.15.1.3 Defining Networks
..........................

Host addresses are usually grouped together into IP networks, so *note
ipaddress: 80. provides a way to create, inspect and manipulate network
definitions.  IP network objects are constructed from strings that
define the range of host addresses that are part of that network.  The
simplest form for that information is a “network address/network prefix”
pair, where the prefix defines the number of leading bits that are
compared to determine whether or not an address is part of the network
and the network address defines the expected value of those bits.

As for addresses, a factory function is provided that determines the
correct IP version automatically:

     >>> ipaddress.ip_network('192.0.2.0/24')
     IPv4Network('192.0.2.0/24')
     >>> ipaddress.ip_network('2001:db8::0/96')
     IPv6Network('2001:db8::/96')

Network objects cannot have any host bits set.  The practical effect of
this is that ‘192.0.2.1/24’ does not describe a network.  Such
definitions are referred to as interface objects since the
ip-on-a-network notation is commonly used to describe network interfaces
of a computer on a given network and are described further in the next
section.

By default, attempting to create a network object with host bits set
will result in *note ValueError: 202. being raised.  To request that the
additional bits instead be coerced to zero, the flag ‘strict=False’ can
be passed to the constructor:

     >>> ipaddress.ip_network('192.0.2.1/24')
     Traceback (most recent call last):
        ...
     ValueError: 192.0.2.1/24 has host bits set
     >>> ipaddress.ip_network('192.0.2.1/24', strict=False)
     IPv4Network('192.0.2.0/24')

While the string form offers significantly more flexibility, networks
can also be defined with integers, just like host addresses.  In this
case, the network is considered to contain only the single address
identified by the integer, so the network prefix includes the entire
network address:

     >>> ipaddress.ip_network(3221225984)
     IPv4Network('192.0.2.0/32')
     >>> ipaddress.ip_network(42540766411282592856903984951653826560)
     IPv6Network('2001:db8::/128')

As with addresses, creation of a particular kind of network can be
forced by calling the class constructor directly instead of using the
factory function.


File: python.info,  Node: Host Interfaces,  Prev: Defining Networks,  Up: Creating Address/Network/Interface objects

9.15.1.4 Host Interfaces
........................

As mentioned just above, if you need to describe an address on a
particular network, neither the address nor the network classes are
sufficient.  Notation like ‘192.0.2.1/24’ is commonly used by network
engineers and the people who write tools for firewalls and routers as
shorthand for “the host ‘192.0.2.1’ on the network ‘192.0.2.0/24’”,
Accordingly, *note ipaddress: 80. provides a set of hybrid classes that
associate an address with a particular network.  The interface for
creation is identical to that for defining network objects, except that
the address portion isn’t constrained to being a network address.

     >>> ipaddress.ip_interface('192.0.2.1/24')
     IPv4Interface('192.0.2.1/24')
     >>> ipaddress.ip_interface('2001:db8::1/96')
     IPv6Interface('2001:db8::1/96')

Integer inputs are accepted (as with networks), and use of a particular
IP version can be forced by calling the relevant constructor directly.


File: python.info,  Node: Inspecting Address/Network/Interface Objects,  Next: Networks as lists of Addresses,  Prev: Creating Address/Network/Interface objects,  Up: An introduction to the ipaddress module

9.15.2 Inspecting Address/Network/Interface Objects
---------------------------------------------------

You’ve gone to the trouble of creating an
IPv(4|6)(Address|Network|Interface) object, so you probably want to get
information about it.  *note ipaddress: 80. tries to make doing this
easy and intuitive.

Extracting the IP version:

     >>> addr4 = ipaddress.ip_address('192.0.2.1')
     >>> addr6 = ipaddress.ip_address('2001:db8::1')
     >>> addr6.version
     6
     >>> addr4.version
     4

Obtaining the network from an interface:

     >>> host4 = ipaddress.ip_interface('192.0.2.1/24')
     >>> host4.network
     IPv4Network('192.0.2.0/24')
     >>> host6 = ipaddress.ip_interface('2001:db8::1/96')
     >>> host6.network
     IPv6Network('2001:db8::/96')

Finding out how many individual addresses are in a network:

     >>> net4 = ipaddress.ip_network('192.0.2.0/24')
     >>> net4.num_addresses
     256
     >>> net6 = ipaddress.ip_network('2001:db8::0/96')
     >>> net6.num_addresses
     4294967296

Iterating through the “usable” addresses on a network:

     >>> net4 = ipaddress.ip_network('192.0.2.0/24')
     >>> for x in net4.hosts():
     ...     print(x)
     192.0.2.1
     192.0.2.2
     192.0.2.3
     192.0.2.4
     ...
     192.0.2.252
     192.0.2.253
     192.0.2.254

Obtaining the netmask (i.e.  set bits corresponding to the network
prefix) or the hostmask (any bits that are not part of the netmask):

     >>> net4 = ipaddress.ip_network('192.0.2.0/24')
     >>> net4.netmask
     IPv4Address('255.255.255.0')
     >>> net4.hostmask
     IPv4Address('0.0.0.255')
     >>> net6 = ipaddress.ip_network('2001:db8::0/96')
     >>> net6.netmask
     IPv6Address('ffff:ffff:ffff:ffff:ffff:ffff::')
     >>> net6.hostmask
     IPv6Address('::ffff:ffff')

Exploding or compressing the address:

     >>> addr6.exploded
     '2001:0db8:0000:0000:0000:0000:0000:0001'
     >>> addr6.compressed
     '2001:db8::1'
     >>> net6.exploded
     '2001:0db8:0000:0000:0000:0000:0000:0000/96'
     >>> net6.compressed
     '2001:db8::/96'

While IPv4 doesn’t support explosion or compression, the associated
objects still provide the relevant properties so that version neutral
code can easily ensure the most concise or most verbose form is used for
IPv6 addresses while still correctly handling IPv4 addresses.


File: python.info,  Node: Networks as lists of Addresses,  Next: Comparisons<4>,  Prev: Inspecting Address/Network/Interface Objects,  Up: An introduction to the ipaddress module

9.15.3 Networks as lists of Addresses
-------------------------------------

It’s sometimes useful to treat networks as lists.  This means it is
possible to index them like this:

     >>> net4[1]
     IPv4Address('192.0.2.1')
     >>> net4[-1]
     IPv4Address('192.0.2.255')
     >>> net6[1]
     IPv6Address('2001:db8::1')
     >>> net6[-1]
     IPv6Address('2001:db8::ffff:ffff')

It also means that network objects lend themselves to using the list
membership test syntax like this:

     if address in network:
         # do something

Containment testing is done efficiently based on the network prefix:

     >>> addr4 = ipaddress.ip_address('192.0.2.1')
     >>> addr4 in ipaddress.ip_network('192.0.2.0/24')
     True
     >>> addr4 in ipaddress.ip_network('192.0.3.0/24')
     False


File: python.info,  Node: Comparisons<4>,  Next: Using IP Addresses with other modules,  Prev: Networks as lists of Addresses,  Up: An introduction to the ipaddress module

9.15.4 Comparisons
------------------

*note ipaddress: 80. provides some simple, hopefully intuitive ways to
compare objects, where it makes sense:

     >>> ipaddress.ip_address('192.0.2.1') < ipaddress.ip_address('192.0.2.2')
     True

A *note TypeError: 2c3. exception is raised if you try to compare
objects of different versions or different types.


File: python.info,  Node: Using IP Addresses with other modules,  Next: Getting more detail when instance creation fails,  Prev: Comparisons<4>,  Up: An introduction to the ipaddress module

9.15.5 Using IP Addresses with other modules
--------------------------------------------

Other modules that use IP addresses (such as *note socket: cc.) usually
won’t accept objects from this module directly.  Instead, they must be
coerced to an integer or string that the other module will accept:

     >>> addr4 = ipaddress.ip_address('192.0.2.1')
     >>> str(addr4)
     '192.0.2.1'
     >>> int(addr4)
     3221225985


File: python.info,  Node: Getting more detail when instance creation fails,  Prev: Using IP Addresses with other modules,  Up: An introduction to the ipaddress module

9.15.6 Getting more detail when instance creation fails
-------------------------------------------------------

When creating address/network/interface objects using the
version-agnostic factory functions, any errors will be reported as *note
ValueError: 202. with a generic error message that simply says the
passed in value was not recognized as an object of that type.  The lack
of a specific error is because it’s necessary to know whether the value
is 'supposed' to be IPv4 or IPv6 in order to provide more detail on why
it has been rejected.

To support use cases where it is useful to have access to this
additional detail, the individual class constructors actually raise the
*note ValueError: 202. subclasses *note ipaddress.AddressValueError:
3ea1. and *note ipaddress.NetmaskValueError: 3ec2. to indicate exactly
which part of the definition failed to parse correctly.

The error messages are significantly more detailed when using the class
constructors directly.  For example:

     >>> ipaddress.ip_address("192.168.0.256")
     Traceback (most recent call last):
       ...
     ValueError: '192.168.0.256' does not appear to be an IPv4 or IPv6 address
     >>> ipaddress.IPv4Address("192.168.0.256")
     Traceback (most recent call last):
       ...
     ipaddress.AddressValueError: Octet 256 (> 255) not permitted in '192.168.0.256'

     >>> ipaddress.ip_network("192.168.0.1/64")
     Traceback (most recent call last):
       ...
     ValueError: '192.168.0.1/64' does not appear to be an IPv4 or IPv6 network
     >>> ipaddress.IPv4Network("192.168.0.1/64")
     Traceback (most recent call last):
       ...
     ipaddress.NetmaskValueError: '64' is not a valid netmask

However, both of the module specific exceptions have *note ValueError:
202. as their parent class, so if you’re not concerned with the
particular type of error, you can still write code like the following:

     try:
         network = ipaddress.IPv4Network(address)
     except ValueError:
         print('address/netmask is invalid for IPv4:', address)


File: python.info,  Node: Instrumenting CPython with DTrace and SystemTap,  Next: Python support for the Linux perf profiler,  Prev: An introduction to the ipaddress module,  Up: Python HOWTOs

9.16 Instrumenting CPython with DTrace and SystemTap
====================================================


author: David Malcolm


author: Łukasz Langa

DTrace and SystemTap are monitoring tools, each providing a way to
inspect what the processes on a computer system are doing.  They both
use domain-specific languages allowing a user to write scripts which:

   - filter which processes are to be observed

   - gather data from the processes of interest

   - generate reports on the data

As of Python 3.6, CPython can be built with embedded “markers”, also
known as “probes”, that can be observed by a DTrace or SystemTap script,
making it easier to monitor what the CPython processes on a system are
doing.

'CPython implementation detail:' DTrace markers are implementation
details of the CPython interpreter.  No guarantees are made about probe
compatibility between versions of CPython.  DTrace scripts can stop
working or work incorrectly without warning when changing CPython
versions.

* Menu:

* Enabling the static markers::
* Static DTrace probes::
* Static SystemTap markers::
* Available static markers::
* SystemTap Tapsets::
* Examples: Examples<39>.


File: python.info,  Node: Enabling the static markers,  Next: Static DTrace probes,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.1 Enabling the static markers
----------------------------------

macOS comes with built-in support for DTrace.  On Linux, in order to
build CPython with the embedded markers for SystemTap, the SystemTap
development tools must be installed.

On a Linux machine, this can be done via:

     $ yum install systemtap-sdt-devel

or:

     $ sudo apt-get install systemtap-sdt-dev

CPython must then be *note configured with the -with-dtrace option:
1f5c.:

     checking for --with-dtrace... yes

On macOS, you can list available DTrace probes by running a Python
process in the background and listing all probes made available by the
Python provider:

     $ python3.6 -q &
     $ sudo dtrace -l -P python$!  # or: dtrace -l -m python3.6

        ID   PROVIDER            MODULE                          FUNCTION NAME
     29564 python18035        python3.6          _PyEval_EvalFrameDefault function-entry
     29565 python18035        python3.6             dtrace_function_entry function-entry
     29566 python18035        python3.6          _PyEval_EvalFrameDefault function-return
     29567 python18035        python3.6            dtrace_function_return function-return
     29568 python18035        python3.6                           collect gc-done
     29569 python18035        python3.6                           collect gc-start
     29570 python18035        python3.6          _PyEval_EvalFrameDefault line
     29571 python18035        python3.6                 maybe_dtrace_line line

On Linux, you can verify if the SystemTap static markers are present in
the built binary by seeing if it contains a “.note.stapsdt” section.

     $ readelf -S ./python | grep .note.stapsdt
     [30] .note.stapsdt        NOTE         0000000000000000 00308d78

If you’ve built Python as a shared library (with the *note
-enable-shared: 869. configure option), you need to look instead within
the shared library.  For example:

     $ readelf -S libpython3.3dm.so.1.0 | grep .note.stapsdt
     [29] .note.stapsdt        NOTE         0000000000000000 00365b68

Sufficiently modern readelf can print the metadata:

     $ readelf -n ./python

     Displaying notes found at file offset 0x00000254 with length 0x00000020:
         Owner                 Data size          Description
         GNU                  0x00000010          NT_GNU_ABI_TAG (ABI version tag)
             OS: Linux, ABI: 2.6.32

     Displaying notes found at file offset 0x00000274 with length 0x00000024:
         Owner                 Data size          Description
         GNU                  0x00000014          NT_GNU_BUILD_ID (unique build ID bitstring)
             Build ID: df924a2b08a7e89f6e11251d4602022977af2670

     Displaying notes found at file offset 0x002d6c30 with length 0x00000144:
         Owner                 Data size          Description
         stapsdt              0x00000031          NT_STAPSDT (SystemTap probe descriptors)
             Provider: python
             Name: gc__start
             Location: 0x00000000004371c3, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf6
             Arguments: -4@%ebx
         stapsdt              0x00000030          NT_STAPSDT (SystemTap probe descriptors)
             Provider: python
             Name: gc__done
             Location: 0x00000000004374e1, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf8
             Arguments: -8@%rax
         stapsdt              0x00000045          NT_STAPSDT (SystemTap probe descriptors)
             Provider: python
             Name: function__entry
             Location: 0x000000000053db6c, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6be8
             Arguments: 8@%rbp 8@%r12 -4@%eax
         stapsdt              0x00000046          NT_STAPSDT (SystemTap probe descriptors)
             Provider: python
             Name: function__return
             Location: 0x000000000053dba8, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bea
             Arguments: 8@%rbp 8@%r12 -4@%eax

The above metadata contains information for SystemTap describing how it
can patch strategically placed machine code instructions to enable the
tracing hooks used by a SystemTap script.


File: python.info,  Node: Static DTrace probes,  Next: Static SystemTap markers,  Prev: Enabling the static markers,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.2 Static DTrace probes
---------------------------

The following example DTrace script can be used to show the call/return
hierarchy of a Python script, only tracing within the invocation of a
function called “start”.  In other words, import-time function
invocations are not going to be listed:

     self int indent;

     python$target:::function-entry
     /copyinstr(arg1) == "start"/
     {
             self->trace = 1;
     }

     python$target:::function-entry
     /self->trace/
     {
             printf("%d\t%*s:", timestamp, 15, probename);
             printf("%*s", self->indent, "");
             printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
             self->indent++;
     }

     python$target:::function-return
     /self->trace/
     {
             self->indent--;
             printf("%d\t%*s:", timestamp, 15, probename);
             printf("%*s", self->indent, "");
             printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
     }

     python$target:::function-return
     /copyinstr(arg1) == "start"/
     {
             self->trace = 0;
     }

It can be invoked like this:

     $ sudo dtrace -q -s call_stack.d -c "python3.6 script.py"

The output looks like this:

     156641360502280  function-entry:call_stack.py:start:23
     156641360518804  function-entry: call_stack.py:function_1:1
     156641360532797  function-entry:  call_stack.py:function_3:9
     156641360546807 function-return:  call_stack.py:function_3:10
     156641360563367 function-return: call_stack.py:function_1:2
     156641360578365  function-entry: call_stack.py:function_2:5
     156641360591757  function-entry:  call_stack.py:function_1:1
     156641360605556  function-entry:   call_stack.py:function_3:9
     156641360617482 function-return:   call_stack.py:function_3:10
     156641360629814 function-return:  call_stack.py:function_1:2
     156641360642285 function-return: call_stack.py:function_2:6
     156641360656770  function-entry: call_stack.py:function_3:9
     156641360669707 function-return: call_stack.py:function_3:10
     156641360687853  function-entry: call_stack.py:function_4:13
     156641360700719 function-return: call_stack.py:function_4:14
     156641360719640  function-entry: call_stack.py:function_5:18
     156641360732567 function-return: call_stack.py:function_5:21
     156641360747370 function-return:call_stack.py:start:28


File: python.info,  Node: Static SystemTap markers,  Next: Available static markers,  Prev: Static DTrace probes,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.3 Static SystemTap markers
-------------------------------

The low-level way to use the SystemTap integration is to use the static
markers directly.  This requires you to explicitly state the binary file
containing them.

For example, this SystemTap script can be used to show the call/return
hierarchy of a Python script:

     probe process("python").mark("function__entry") {
          filename = user_string($arg1);
          funcname = user_string($arg2);
          lineno = $arg3;

          printf("%s => %s in %s:%d\\n",
                 thread_indent(1), funcname, filename, lineno);
     }

     probe process("python").mark("function__return") {
         filename = user_string($arg1);
         funcname = user_string($arg2);
         lineno = $arg3;

         printf("%s <= %s in %s:%d\\n",
                thread_indent(-1), funcname, filename, lineno);
     }

It can be invoked like this:

     $ stap \
       show-call-hierarchy.stp \
       -c "./python test.py"

The output looks like this:

     11408 python(8274):        => __contains__ in Lib/_abcoll.py:362
     11414 python(8274):         => __getitem__ in Lib/os.py:425
     11418 python(8274):          => encode in Lib/os.py:490
     11424 python(8274):          <= encode in Lib/os.py:493
     11428 python(8274):         <= __getitem__ in Lib/os.py:426
     11433 python(8274):        <= __contains__ in Lib/_abcoll.py:366

where the columns are:

   - time in microseconds since start of script

   - name of executable

   - PID of process

and the remainder indicates the call/return hierarchy as the script
executes.

For a *note -enable-shared: 869. build of CPython, the markers are
contained within the libpython shared library, and the probe’s dotted
path needs to reflect this.  For example, this line from the above
example:

     probe process("python").mark("function__entry") {

should instead read:

     probe process("python").library("libpython3.6dm.so.1.0").mark("function__entry") {

(assuming a *note debug build: 1f9. of CPython 3.6)


File: python.info,  Node: Available static markers,  Next: SystemTap Tapsets,  Prev: Static SystemTap markers,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.4 Available static markers
-------------------------------

 -- Object: function__entry(str filename, str funcname, int lineno)

     This marker indicates that execution of a Python function has
     begun.  It is only triggered for pure-Python (bytecode) functions.

     The filename, function name, and line number are provided back to
     the tracing script as positional arguments, which must be accessed
     using ‘$arg1’, ‘$arg2’, ‘$arg3’:

             * ‘$arg1’ : ‘(const char *)’ filename, accessible using
               ‘user_string($arg1)’

             * ‘$arg2’ : ‘(const char *)’ function name, accessible
               using ‘user_string($arg2)’

             * ‘$arg3’ : ‘int’ line number

 -- Object: function__return(str filename, str funcname, int lineno)

     This marker is the converse of ‘function__entry()’, and indicates
     that execution of a Python function has ended (either via ‘return’,
     or via an exception).  It is only triggered for pure-Python
     (bytecode) functions.

     The arguments are the same as for ‘function__entry()’

 -- Object: line(str filename, str funcname, int lineno)

     This marker indicates a Python line is about to be executed.  It is
     the equivalent of line-by-line tracing with a Python profiler.  It
     is not triggered within C functions.

     The arguments are the same as for ‘function__entry()’.

 -- Object: gc__start(int generation)

     Fires when the Python interpreter starts a garbage collection
     cycle.  ‘arg0’ is the generation to scan, like *note gc.collect():
     a47.

 -- Object: gc__done(long collected)

     Fires when the Python interpreter finishes a garbage collection
     cycle.  ‘arg0’ is the number of collected objects.

 -- Object: import__find__load__start(str modulename)

     Fires before *note importlib: 77. attempts to find and load the
     module.  ‘arg0’ is the module name.

     Added in version 3.7.

 -- Object: import__find__load__done(str modulename, int found)

     Fires after *note importlib: 77.’s find_and_load function is
     called.  ‘arg0’ is the module name, ‘arg1’ indicates if module was
     successfully loaded.

     Added in version 3.7.

 -- Object: audit(str event, void *tuple)

     Fires when *note sys.audit(): 16be. or *note PySys_Audit(): 372. is
     called.  ‘arg0’ is the event name as C string, ‘arg1’ is a *note
     PyObject: 33a. pointer to a tuple object.

     Added in version 3.8.

* Menu:

* C Entry Points::
* C Probing Checks::


File: python.info,  Node: C Entry Points,  Next: C Probing Checks,  Up: Available static markers

9.16.4.1 C Entry Points
.......................

To simplify triggering of DTrace markers, Python’s C API comes with a
number of helper functions that mirror each static marker.  On builds of
Python without DTrace enabled, these do nothing.

In general, it is not necessary to call these yourself, as Python will
do it for you.

C API Function                                         Static Marker                 Notes
                                                                                     
-------------------------------------------------------------------------------------------------------------------
                                                                                     
 -- C Function: void PyDTrace_LINE (const char         ‘line()’
          *arg0, const char *arg1, int arg2)           

 -- C Function: void PyDTrace_FUNCTION_ENTRY (const    ‘function__entry()’
          char *arg0, const char *arg1, int arg2)      

 -- C Function: void PyDTrace_FUNCTION_RETURN (const   ‘function__return()’
          char *arg0, const char *arg1, int arg2)      

 -- C Function: void PyDTrace_GC_START (int arg0)      ‘gc__start()’
                                                       
                                                                                     
 -- C Function: void PyDTrace_GC_DONE (Py_ssize_t      ‘gc__done()’
          arg0)                                        

 -- C Function: void PyDTrace_INSTANCE_NEW_START       ‘instance__new__start()’      Not used by Python
          (int arg0)                                                                 

 -- C Function: void PyDTrace_INSTANCE_NEW_DONE (int   ‘instance__new__done()’       Not used by Python
          arg0)                                                                      

 -- C Function: void PyDTrace_INSTANCE_DELETE_START    ‘instance__delete__start()’   Not used by Python
          (int arg0)                                                                 

 -- C Function: void PyDTrace_INSTANCE_DELETE_DONE     ‘instance__delete__done()’    Not used by Python
          (int arg0)                                                                 

 -- C Function: void PyDTrace_IMPORT_FIND_LOAD_START   ‘import__find__load__start()’
          (const char *arg0)                           

 -- C Function: void PyDTrace_IMPORT_FIND_LOAD_DONE    ‘import__find__load__done()’
          (const char *arg0, int arg1)                 

 -- C Function: void PyDTrace_AUDIT (const char        ‘audit()’
          *arg0, void *arg1)                           


File: python.info,  Node: C Probing Checks,  Prev: C Entry Points,  Up: Available static markers

9.16.4.2 C Probing Checks
.........................

 -- C Function: int PyDTrace_LINE_ENABLED (void)

 -- C Function: int PyDTrace_FUNCTION_ENTRY_ENABLED (void)

 -- C Function: int PyDTrace_FUNCTION_RETURN_ENABLED (void)

 -- C Function: int PyDTrace_GC_START_ENABLED (void)

 -- C Function: int PyDTrace_GC_DONE_ENABLED (void)

 -- C Function: int PyDTrace_INSTANCE_NEW_START_ENABLED (void)

 -- C Function: int PyDTrace_INSTANCE_NEW_DONE_ENABLED (void)

 -- C Function: int PyDTrace_INSTANCE_DELETE_START_ENABLED (void)

 -- C Function: int PyDTrace_INSTANCE_DELETE_DONE_ENABLED (void)

 -- C Function: int PyDTrace_IMPORT_FIND_LOAD_START_ENABLED (void)

 -- C Function: int PyDTrace_IMPORT_FIND_LOAD_DONE_ENABLED (void)

 -- C Function: int PyDTrace_AUDIT_ENABLED (void)

     All calls to ‘PyDTrace’ functions must be guarded by a call to one
     of these functions.  This allows Python to minimize performance
     impact when probing is disabled.

     On builds without DTrace enabled, these functions do nothing and
     return ‘0’.


File: python.info,  Node: SystemTap Tapsets,  Next: Examples<39>,  Prev: Available static markers,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.5 SystemTap Tapsets
------------------------

The higher-level way to use the SystemTap integration is to use a
“tapset”: SystemTap’s equivalent of a library, which hides some of the
lower-level details of the static markers.

Here is a tapset file, based on a non-shared build of CPython:

     /*
        Provide a higher-level wrapping around the function__entry and
        function__return markers:
      \*/
     probe python.function.entry = process("python").mark("function__entry")
     {
         filename = user_string($arg1);
         funcname = user_string($arg2);
         lineno = $arg3;
         frameptr = $arg4
     }
     probe python.function.return = process("python").mark("function__return")
     {
         filename = user_string($arg1);
         funcname = user_string($arg2);
         lineno = $arg3;
         frameptr = $arg4
     }

If this file is installed in SystemTap’s tapset directory (e.g.
‘/usr/share/systemtap/tapset’), then these additional probepoints become
available:

 -- Object: python.function.entry(str filename, str funcname, int
          lineno, frameptr)

     This probe point indicates that execution of a Python function has
     begun.  It is only triggered for pure-Python (bytecode) functions.

 -- Object: python.function.return(str filename, str funcname, int
          lineno, frameptr)

     This probe point is the converse of ‘python.function.return’, and
     indicates that execution of a Python function has ended (either via
     ‘return’, or via an exception).  It is only triggered for
     pure-Python (bytecode) functions.


File: python.info,  Node: Examples<39>,  Prev: SystemTap Tapsets,  Up: Instrumenting CPython with DTrace and SystemTap

9.16.6 Examples
---------------

This SystemTap script uses the tapset above to more cleanly implement
the example given above of tracing the Python function-call hierarchy,
without needing to directly name the static markers:

     probe python.function.entry
     {
       printf("%s => %s in %s:%d\n",
              thread_indent(1), funcname, filename, lineno);
     }

     probe python.function.return
     {
       printf("%s <= %s in %s:%d\n",
              thread_indent(-1), funcname, filename, lineno);
     }

The following script uses the tapset above to provide a top-like view of
all running CPython code, showing the top 20 most frequently entered
bytecode frames, each second, across the whole system:

     global fn_calls;

     probe python.function.entry
     {
         fn_calls[pid(), filename, funcname, lineno] += 1;
     }

     probe timer.ms(1000) {
         printf("\033[2J\033[1;1H") /* clear screen \*/
         printf("%6s %80s %6s %30s %6s\n",
                "PID", "FILENAME", "LINE", "FUNCTION", "CALLS")
         foreach ([pid, filename, funcname, lineno] in fn_calls- limit 20) {
             printf("%6d %80s %6d %30s %6d\n",
                 pid, filename, lineno, funcname,
                 fn_calls[pid, filename, funcname, lineno]);
         }
         delete fn_calls;
     }


File: python.info,  Node: Python support for the Linux perf profiler,  Next: Annotations Best Practices,  Prev: Instrumenting CPython with DTrace and SystemTap,  Up: Python HOWTOs

9.17 Python support for the Linux ‘perf’ profiler
=================================================


author: Pablo Galindo

The Linux perf profiler(1) is a very powerful tool that allows you to
profile and obtain information about the performance of your
application.  ‘perf’ also has a very vibrant ecosystem of tools that aid
with the analysis of the data that it produces.

The main problem with using the ‘perf’ profiler with Python applications
is that ‘perf’ only gets information about native symbols, that is, the
names of functions and procedures written in C. This means that the
names and file names of Python functions in your code will not appear in
the output of ‘perf’.

Since Python 3.12, the interpreter can run in a special mode that allows
Python functions to appear in the output of the ‘perf’ profiler.  When
this mode is enabled, the interpreter will interpose a small piece of
code compiled on the fly before the execution of every Python function
and it will teach ‘perf’ the relationship between this piece of code and
the associated Python function using *note perf map files: 4f23.

     Note: Support for the ‘perf’ profiler is currently only available
     for Linux on select architectures.  Check the output of the
     ‘configure’ build step or check the output of ‘python -m sysconfig
     | grep HAVE_PERF_TRAMPOLINE’ to see if your system is supported.

For example, consider the following script:

     def foo(n):
         result = 0
         for _ in range(n):
             result += 1
         return result

     def bar(n):
         foo(n)

     def baz(n):
         bar(n)

     if __name__ == "__main__":
         baz(1000000)

We can run ‘perf’ to sample CPU stack traces at 9999 hertz:

     $ perf record -F 9999 -g -o perf.data python my_script.py

Then we can use ‘perf report’ to analyze the data:

     $ perf report --stdio -n -g

     # Children      Self       Samples  Command     Shared Object       Symbol
     # ........  ........  ............  ..........  ..................  ..........................................
     #
         91.08%     0.00%             0  python.exe  python.exe          [.] _start
                 |
                 ---_start
                 |
                     --90.71%--__libc_start_main
                             Py_BytesMain
                             |
                             |--56.88%--pymain_run_python.constprop.0
                             |          |
                             |          |--56.13%--_PyRun_AnyFileObject
                             |          |          _PyRun_SimpleFileObject
                             |          |          |
                             |          |          |--55.02%--run_mod
                             |          |          |          |
                             |          |          |           --54.65%--PyEval_EvalCode
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     |
                             |          |          |                     |--51.67%--_PyEval_EvalFrameDefault
                             |          |          |                     |          |
                             |          |          |                     |          |--11.52%--_PyLong_Add
                             |          |          |                     |          |          |
                             |          |          |                     |          |          |--2.97%--_PyObject_Malloc
     ...

As you can see, the Python functions are not shown in the output, only
‘_PyEval_EvalFrameDefault’ (the function that evaluates the Python
bytecode) shows up.  Unfortunately that’s not very useful because all
Python functions use the same C function to evaluate bytecode so we
cannot know which Python function corresponds to which
bytecode-evaluating function.

Instead, if we run the same experiment with ‘perf’ support enabled we
get:

     $ perf report --stdio -n -g

     # Children      Self       Samples  Command     Shared Object       Symbol
     # ........  ........  ............  ..........  ..................  .....................................................................
     #
         90.58%     0.36%             1  python.exe  python.exe          [.] _start
                 |
                 ---_start
                 |
                     --89.86%--__libc_start_main
                             Py_BytesMain
                             |
                             |--55.43%--pymain_run_python.constprop.0
                             |          |
                             |          |--54.71%--_PyRun_AnyFileObject
                             |          |          _PyRun_SimpleFileObject
                             |          |          |
                             |          |          |--53.62%--run_mod
                             |          |          |          |
                             |          |          |           --53.26%--PyEval_EvalCode
                             |          |          |                     py::<module>:/src/script.py
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     py::baz:/src/script.py
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     py::bar:/src/script.py
                             |          |          |                     _PyEval_EvalFrameDefault
                             |          |          |                     PyObject_Vectorcall
                             |          |          |                     _PyEval_Vector
                             |          |          |                     py::foo:/src/script.py
                             |          |          |                     |
                             |          |          |                     |--51.81%--_PyEval_EvalFrameDefault
                             |          |          |                     |          |
                             |          |          |                     |          |--13.77%--_PyLong_Add
                             |          |          |                     |          |          |
                             |          |          |                     |          |          |--3.26%--_PyObject_Malloc

* Menu:

* How to enable perf profiling support::
* How to obtain the best results::
* How to work without frame pointers::

   ---------- Footnotes ----------

   (1) https://perf.wiki.kernel.org


File: python.info,  Node: How to enable perf profiling support,  Next: How to obtain the best results,  Up: Python support for the Linux perf profiler

9.17.1 How to enable ‘perf’ profiling support
---------------------------------------------

‘perf’ profiling support can be enabled either from the start using the
environment variable *note PYTHONPERFSUPPORT: 471. or the *note -X perf:
176. option, or dynamically using *note sys.activate_stack_trampoline():
472. and *note sys.deactivate_stack_trampoline(): 473.

The ‘sys’ functions take precedence over the ‘-X’ option, the ‘-X’
option takes precedence over the environment variable.

Example, using the environment variable:

     $ PYTHONPERFSUPPORT=1 perf record -F 9999 -g -o perf.data python my_script.py
     $ perf report -g -i perf.data

Example, using the ‘-X’ option:

     $ perf record -F 9999 -g -o perf.data python -X perf my_script.py
     $ perf report -g -i perf.data

Example, using the *note sys: d9. APIs in file ‘example.py’:

     import sys

     sys.activate_stack_trampoline("perf")
     do_profiled_stuff()
     sys.deactivate_stack_trampoline()

     non_profiled_stuff()

…then:

     $ perf record -F 9999 -g -o perf.data python ./example.py
     $ perf report -g -i perf.data


File: python.info,  Node: How to obtain the best results,  Next: How to work without frame pointers,  Prev: How to enable perf profiling support,  Up: Python support for the Linux perf profiler

9.17.2 How to obtain the best results
-------------------------------------

For best results, Python should be compiled with
‘CFLAGS="-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer"’ as this
allows profilers to unwind using only the frame pointer and not on DWARF
debug information.  This is because as the code that is interposed to
allow ‘perf’ support is dynamically generated it doesn’t have any DWARF
debugging information available.

You can check if your system has been compiled with this flag by
running:

     $ python -m sysconfig | grep 'no-omit-frame-pointer'

If you don’t see any output it means that your interpreter has not been
compiled with frame pointers and therefore it may not be able to show
Python functions in the output of ‘perf’.


File: python.info,  Node: How to work without frame pointers,  Prev: How to obtain the best results,  Up: Python support for the Linux perf profiler

9.17.3 How to work without frame pointers
-----------------------------------------

If you are working with a Python interpreter that has been compiled
without frame pointers, you can still use the ‘perf’ profiler, but the
overhead will be a bit higher because Python needs to generate unwinding
information for every Python function call on the fly.  Additionally,
‘perf’ will take more time to process the data because it will need to
use the DWARF debugging information to unwind the stack and this is a
slow process.

To enable this mode, you can use the environment variable *note
PYTHON_PERF_JIT_SUPPORT: 190. or the *note -X perf_jit: 176. option,
which will enable the JIT mode for the ‘perf’ profiler.

     Note: Due to a bug in the ‘perf’ tool, only ‘perf’ versions higher
     than v6.8 will work with the JIT mode.  The fix was also backported
     to the v6.7.2 version of the tool.

     Note that when checking the version of the ‘perf’ tool (which can
     be done by running ‘perf version’) you must take into account that
     some distros add some custom version numbers including a ‘-’
     character.  This means that ‘perf 6.7-3’ is not necessarily ‘perf
     6.7.3’.

When using the perf JIT mode, you need an extra step before you can run
‘perf report’.  You need to call the ‘perf inject’ command to inject the
JIT information into the ‘perf.data’ file.:

     $ perf record -F 9999 -g -k 1 --call-graph dwarf -o perf.data python -Xperf_jit my_script.py
     $ perf inject -i perf.data --jit --output perf.jit.data
     $ perf report -g -i perf.jit.data

or using the environment variable:

     $ PYTHON_PERF_JIT_SUPPORT=1 perf record -F 9999 -g --call-graph dwarf -o perf.data python my_script.py
     $ perf inject -i perf.data --jit --output perf.jit.data
     $ perf report -g -i perf.jit.data

‘perf inject --jit’ command will read ‘perf.data’, automatically pick up
the perf dump file that Python creates (in ‘/tmp/perf-$PID.dump’), and
then create ‘perf.jit.data’ which merges all the JIT information
together.  It should also create a lot of ‘jitted-XXXX-N.so’ files in
the current directory which are ELF images for all the JIT trampolines
that were created by Python.

     Warning: When using ‘--call-graph dwarf’, the ‘perf’ tool will take
     snapshots of the stack of the process being profiled and save the
     information in the ‘perf.data’ file.  By default, the size of the
     stack dump is 8192 bytes, but you can change the size by passing it
     after a comma like ‘--call-graph dwarf,16384’.

     The size of the stack dump is important because if the size is too
     small ‘perf’ will not be able to unwind the stack and the output
     will be incomplete.  On the other hand, if the size is too big,
     then ‘perf’ won’t be able to sample the process as frequently as it
     would like as the overhead will be higher.

     The stack size is particularly important when profiling Python code
     compiled with low optimization levels (like ‘-O0’), as these builds
     tend to have larger stack frames.  If you are compiling Python with
     ‘-O0’ and not seeing Python functions in your profiling output, try
     increasing the stack dump size to 65528 bytes (the maximum):

          $ perf record -F 9999 -g -k 1 --call-graph dwarf,65528 -o perf.data python -Xperf_jit my_script.py

     Different compilation flags can significantly impact stack sizes:

        - Builds with ‘-O0’ typically have much larger stack frames than
          those with ‘-O1’ or higher

        - Adding optimizations (‘-O1’, ‘-O2’, etc.)  typically reduces
          stack size

        - Frame pointers (‘-fno-omit-frame-pointer’) generally provide
          more reliable stack unwinding


File: python.info,  Node: Annotations Best Practices,  Next: Isolating Extension Modules,  Prev: Python support for the Linux perf profiler,  Up: Python HOWTOs

9.18 Annotations Best Practices
===============================


author: Larry Hastings

Abstract
........

This document is designed to encapsulate the best practices for working
with annotations dicts.  If you write Python code that examines
‘__annotations__’ on Python objects, we encourage you to follow the
guidelines described below.

The document is organized into four sections: best practices for
accessing the annotations of an object in Python versions 3.10 and
newer, best practices for accessing the annotations of an object in
Python versions 3.9 and older, other best practices for
‘__annotations__’ that apply to any Python version, and quirks of
‘__annotations__’.

Note that this document is specifically about working with
‘__annotations__’, not uses 'for' annotations.  If you’re looking for
information on how to use “type hints” in your code, please see the
*note typing: 104. module.

* Menu:

* Accessing The Annotations Dict Of An Object In Python 3.10 And Newer: Accessing The Annotations Dict Of An Object In Python 3 10 And Newer.
* Accessing The Annotations Dict Of An Object In Python 3.9 And Older: Accessing The Annotations Dict Of An Object In Python 3 9 And Older.
* Manually Un-Stringizing Stringized Annotations::
* Best Practices For __annotations__ In Any Python Version::
* __annotations__ Quirks::


File: python.info,  Node: Accessing The Annotations Dict Of An Object In Python 3 10 And Newer,  Next: Accessing The Annotations Dict Of An Object In Python 3 9 And Older,  Up: Annotations Best Practices

9.18.1 Accessing The Annotations Dict Of An Object In Python 3.10 And Newer
---------------------------------------------------------------------------

Python 3.10 adds a new function to the standard library: *note
inspect.get_annotations(): 819.  In Python versions 3.10 and newer,
calling this function is the best practice for accessing the annotations
dict of any object that supports annotations.  This function can also
“un-stringize” stringized annotations for you.

If for some reason *note inspect.get_annotations(): 819. isn’t viable
for your use case, you may access the ‘__annotations__’ data member
manually.  Best practice for this changed in Python 3.10 as well: as of
Python 3.10, ‘o.__annotations__’ is guaranteed to 'always' work on
Python functions, classes, and modules.  If you’re certain the object
you’re examining is one of these three 'specific' objects, you may
simply use ‘o.__annotations__’ to get at the object’s annotations dict.

However, other types of callables–for example, callables created by
*note functools.partial(): 417.–may not have an ‘__annotations__’
attribute defined.  When accessing the ‘__annotations__’ of a possibly
unknown object, best practice in Python versions 3.10 and newer is to
call *note getattr(): bf0. with three arguments, for example ‘getattr(o,
'__annotations__', None)’.

Before Python 3.10, accessing ‘__annotations__’ on a class that defines
no annotations but that has a parent class with annotations would return
the parent’s ‘__annotations__’.  In Python 3.10 and newer, the child
class’s annotations will be an empty dict instead.


File: python.info,  Node: Accessing The Annotations Dict Of An Object In Python 3 9 And Older,  Next: Manually Un-Stringizing Stringized Annotations,  Prev: Accessing The Annotations Dict Of An Object In Python 3 10 And Newer,  Up: Annotations Best Practices

9.18.2 Accessing The Annotations Dict Of An Object In Python 3.9 And Older
--------------------------------------------------------------------------

In Python 3.9 and older, accessing the annotations dict of an object is
much more complicated than in newer versions.  The problem is a design
flaw in these older versions of Python, specifically to do with class
annotations.

Best practice for accessing the annotations dict of other
objects–functions, other callables, and modules–is the same as best
practice for 3.10, assuming you aren’t calling *note
inspect.get_annotations(): 819.: you should use three-argument *note
getattr(): bf0. to access the object’s ‘__annotations__’ attribute.

Unfortunately, this isn’t best practice for classes.  The problem is
that, since ‘__annotations__’ is optional on classes, and because
classes can inherit attributes from their base classes, accessing the
‘__annotations__’ attribute of a class may inadvertently return the
annotations dict of a 'base class.'  As an example:

     class Base:
         a: int = 3
         b: str = 'abc'

     class Derived(Base):
         pass

     print(Derived.__annotations__)

This will print the annotations dict from ‘Base’, not ‘Derived’.

Your code will have to have a separate code path if the object you’re
examining is a class (‘isinstance(o, type)’).  In that case, best
practice relies on an implementation detail of Python 3.9 and before: if
a class has annotations defined, they are stored in the class’s *note
__dict__: c7e. dictionary.  Since the class may or may not have
annotations defined, best practice is to call the *note get(): 1dea.
method on the class dict.

To put it all together, here is some sample code that safely accesses
the ‘__annotations__’ attribute on an arbitrary object in Python 3.9 and
before:

     if isinstance(o, type):
         ann = o.__dict__.get('__annotations__', None)
     else:
         ann = getattr(o, '__annotations__', None)

After running this code, ‘ann’ should be either a dictionary or ‘None’.
You’re encouraged to double-check the type of ‘ann’ using *note
isinstance(): 445. before further examination.

Note that some exotic or malformed type objects may not have a *note
__dict__: c7e. attribute, so for extra safety you may also wish to use
*note getattr(): bf0. to access ‘__dict__’.


File: python.info,  Node: Manually Un-Stringizing Stringized Annotations,  Next: Best Practices For __annotations__ In Any Python Version,  Prev: Accessing The Annotations Dict Of An Object In Python 3 9 And Older,  Up: Annotations Best Practices

9.18.3 Manually Un-Stringizing Stringized Annotations
-----------------------------------------------------

In situations where some annotations may be “stringized”, and you wish
to evaluate those strings to produce the Python values they represent,
it really is best to call *note inspect.get_annotations(): 819. to do
this work for you.

If you’re using Python 3.9 or older, or if for some reason you can’t use
*note inspect.get_annotations(): 819, you’ll need to duplicate its
logic.  You’re encouraged to examine the implementation of
‘inspect.get_annotations()’ in the current Python version and follow a
similar approach.

In a nutshell, if you wish to evaluate a stringized annotation on an
arbitrary object ‘o’:

   * If ‘o’ is a module, use ‘o.__dict__’ as the ‘globals’ when calling
     *note eval(): 180.

   * If ‘o’ is a class, use ‘sys.modules[o.__module__].__dict__’ as the
     ‘globals’, and ‘dict(vars(o))’ as the ‘locals’, when calling *note
     eval(): 180.

   * If ‘o’ is a wrapped callable using *note
     functools.update_wrapper(): 105d, *note functools.wraps(): f96, or
     *note functools.partial(): 417, iteratively unwrap it by accessing
     either ‘o.__wrapped__’ or ‘o.func’ as appropriate, until you have
     found the root unwrapped function.

   * If ‘o’ is a callable (but not a class), use *note o.__globals__:
     131b. as the globals when calling *note eval(): 180.

However, not all string values used as annotations can be successfully
turned into Python values by *note eval(): 180.  String values could
theoretically contain any valid string, and in practice there are valid
use cases for type hints that require annotating with string values that
specifically 'can’t' be evaluated.  For example:

   * PEP 604(1) union types using ‘|’, before support for this was added
     to Python 3.10.

   * Definitions that aren’t needed at runtime, only imported when *note
     typing.TYPE_CHECKING: d1b. is true.

If *note eval(): 180. attempts to evaluate such values, it will fail and
raise an exception.  So, when designing a library API that works with
annotations, it’s recommended to only attempt to evaluate string values
when explicitly requested to by the caller.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0604/


File: python.info,  Node: Best Practices For __annotations__ In Any Python Version,  Next: __annotations__ Quirks,  Prev: Manually Un-Stringizing Stringized Annotations,  Up: Annotations Best Practices

9.18.4 Best Practices For ‘__annotations__’ In Any Python Version
-----------------------------------------------------------------

   * You should avoid assigning to the ‘__annotations__’ member of
     objects directly.  Let Python manage setting ‘__annotations__’.

   * If you do assign directly to the ‘__annotations__’ member of an
     object, you should always set it to a ‘dict’ object.

   * If you directly access the ‘__annotations__’ member of an object,
     you should ensure that it’s a dictionary before attempting to
     examine its contents.

   * You should avoid modifying ‘__annotations__’ dicts.

   * You should avoid deleting the ‘__annotations__’ attribute of an
     object.


File: python.info,  Node: __annotations__ Quirks,  Prev: Best Practices For __annotations__ In Any Python Version,  Up: Annotations Best Practices

9.18.5 ‘__annotations__’ Quirks
-------------------------------

In all versions of Python 3, function objects lazy-create an annotations
dict if no annotations are defined on that object.  You can delete the
‘__annotations__’ attribute using ‘del fn.__annotations__’, but if you
then access ‘fn.__annotations__’ the object will create a new empty dict
that it will store and return as its annotations.  Deleting the
annotations on a function before it has lazily created its annotations
dict will throw an ‘AttributeError’; using ‘del fn.__annotations__’
twice in a row is guaranteed to always throw an ‘AttributeError’.

Everything in the above paragraph also applies to class and module
objects in Python 3.10 and newer.

In all versions of Python 3, you can set ‘__annotations__’ on a function
object to ‘None’.  However, subsequently accessing the annotations on
that object using ‘fn.__annotations__’ will lazy-create an empty
dictionary as per the first paragraph of this section.  This is 'not'
true of modules and classes, in any Python version; those objects permit
setting ‘__annotations__’ to any Python value, and will retain whatever
value is set.

If Python stringizes your annotations for you (using ‘from __future__
import annotations’), and you specify a string as an annotation, the
string will itself be quoted.  In effect the annotation is quoted
'twice.'  For example:

     from __future__ import annotations
     def foo(a: "str"): pass

     print(foo.__annotations__)

This prints ‘{'a': "'str'"}’.  This shouldn’t really be considered a
“quirk”; it’s mentioned here simply because it might be surprising.


File: python.info,  Node: Isolating Extension Modules,  Next: timer file descriptor HOWTO,  Prev: Annotations Best Practices,  Up: Python HOWTOs

9.19 Isolating Extension Modules
================================

Abstract
........

Traditionally, state belonging to Python extension modules was kept in C
‘static’ variables, which have process-wide scope.  This document
describes problems of such per-process state and shows a safer way:
per-module state.

The document also describes how to switch to per-module state where
possible.  This transition involves allocating space for that state,
potentially switching from static types to heap types, and—perhaps most
importantly—accessing per-module state from code.

* Menu:

* Who should read this::
* Background: Background<2>.
* Making Modules Safe with Multiple Interpreters::
* Heap Types: Heap Types<2>.
* Open Issues::


File: python.info,  Node: Who should read this,  Next: Background<2>,  Up: Isolating Extension Modules

9.19.1 Who should read this
---------------------------

This guide is written for maintainers of *note C-API: 1d6f. extensions
who would like to make that extension safer to use in applications where
Python itself is used as a library.


File: python.info,  Node: Background<2>,  Next: Making Modules Safe with Multiple Interpreters,  Prev: Who should read this,  Up: Isolating Extension Modules

9.19.2 Background
-----------------

An 'interpreter' is the context in which Python code runs.  It contains
configuration (e.g.  the import path) and runtime state (e.g.  the set
of imported modules).

Python supports running multiple interpreters in one process.  There are
two cases to think about—users may run interpreters:

   - in sequence, with several *note Py_InitializeEx(): 4df3./*note
     Py_FinalizeEx(): d3d. cycles, and

   - in parallel, managing “sub-interpreters” using *note
     Py_NewInterpreter(): 18d4./*note Py_EndInterpreter(): 19a0.

Both cases (and combinations of them) would be most useful when
embedding Python within a library.  Libraries generally shouldn’t make
assumptions about the application that uses them, which include assuming
a process-wide “main Python interpreter”.

Historically, Python extension modules don’t handle this use case well.
Many extension modules (and even some stdlib modules) use 'per-process'
global state, because C ‘static’ variables are extremely easy to use.
Thus, data that should be specific to an interpreter ends up being
shared between interpreters.  Unless the extension developer is careful,
it is very easy to introduce edge cases that lead to crashes when a
module is loaded in more than one interpreter in the same process.

Unfortunately, 'per-interpreter' state is not easy to achieve.
Extension authors tend to not keep multiple interpreters in mind when
developing, and it is currently cumbersome to test the behavior.

* Menu:

* Enter Per-Module State::
* Isolated Module Objects::
* Surprising Edge Cases::


File: python.info,  Node: Enter Per-Module State,  Next: Isolated Module Objects,  Up: Background<2>

9.19.2.1 Enter Per-Module State
...............................

Instead of focusing on per-interpreter state, Python’s C API is evolving
to better support the more granular 'per-module' state.  This means that
C-level data should be attached to a 'module object'.  Each interpreter
creates its own module object, keeping the data separate.  For testing
the isolation, multiple module objects corresponding to a single
extension can even be loaded in a single interpreter.

Per-module state provides an easy way to think about lifetime and
resource ownership: the extension module will initialize when a module
object is created, and clean up when it’s freed.  In this regard, a
module is just like any other *note PyObject: 33a.*; there are no “on
interpreter shutdown” hooks to think—or forget—about.

Note that there are use cases for different kinds of “globals”:
per-process, per-interpreter, per-thread or per-task state.  With
per-module state as the default, these are still possible, but you
should treat them as exceptional cases: if you need them, you should
give them additional care and testing.  (Note that this guide does not
cover them.)


File: python.info,  Node: Isolated Module Objects,  Next: Surprising Edge Cases,  Prev: Enter Per-Module State,  Up: Background<2>

9.19.2.2 Isolated Module Objects
................................

The key point to keep in mind when developing an extension module is
that several module objects can be created from a single shared library.
For example:

     >>> import sys
     >>> import binascii
     >>> old_binascii = binascii
     >>> del sys.modules['binascii']
     >>> import binascii  # create a new module object
     >>> old_binascii == binascii
     False

As a rule of thumb, the two modules should be completely independent.
All objects and state specific to the module should be encapsulated
within the module object, not shared with other module objects, and
cleaned up when the module object is deallocated.  Since this just is a
rule of thumb, exceptions are possible (see *note Managing Global State:
54cc.), but they will need more thought and attention to edge cases.

While some modules could do with less stringent restrictions, isolated
modules make it easier to set clear expectations and guidelines that
work across a variety of use cases.


File: python.info,  Node: Surprising Edge Cases,  Prev: Isolated Module Objects,  Up: Background<2>

9.19.2.3 Surprising Edge Cases
..............................

Note that isolated modules do create some surprising edge cases.  Most
notably, each module object will typically not share its classes and
exceptions with other similar modules.  Continuing from the *note
example above: 54cb, note that ‘old_binascii.Error’ and ‘binascii.Error’
are separate objects.  In the following code, the exception is 'not'
caught:

     >>> old_binascii.Error == binascii.Error
     False
     >>> try:
     ...     old_binascii.unhexlify(b'qwertyuiop')
     ... except binascii.Error:
     ...     print('boo')
     ...
     Traceback (most recent call last):
       File "<stdin>", line 2, in <module>
     binascii.Error: Non-hexadecimal digit found

This is expected.  Notice that pure-Python modules behave the same way:
it is a part of how Python works.

The goal is to make extension modules safe at the C level, not to make
hacks behave intuitively.  Mutating ‘sys.modules’ “manually” counts as a
hack.


File: python.info,  Node: Making Modules Safe with Multiple Interpreters,  Next: Heap Types<2>,  Prev: Background<2>,  Up: Isolating Extension Modules

9.19.3 Making Modules Safe with Multiple Interpreters
-----------------------------------------------------

* Menu:

* Managing Global State::
* Managing Per-Module State::
* Opt-Out; Limiting to One Module Object per Process: Opt-Out Limiting to One Module Object per Process.
* Module State Access from Functions::


File: python.info,  Node: Managing Global State,  Next: Managing Per-Module State,  Up: Making Modules Safe with Multiple Interpreters

9.19.3.1 Managing Global State
..............................

Sometimes, the state associated with a Python module is not specific to
that module, but to the entire process (or something else “more global”
than a module).  For example:

   - The ‘readline’ module manages 'the' terminal.

   - A module running on a circuit board wants to control 'the' on-board
     LED.

In these cases, the Python module should provide 'access' to the global
state, rather than 'own' it.  If possible, write the module so that
multiple copies of it can access the state independently (along with
other libraries, whether for Python or other languages).  If that is not
possible, consider explicit locking.

If it is necessary to use process-global state, the simplest way to
avoid issues with multiple interpreters is to explicitly prevent a
module from being loaded more than once per process—see *note Opt-Out;
Limiting to One Module Object per Process: 50ea.


File: python.info,  Node: Managing Per-Module State,  Next: Opt-Out Limiting to One Module Object per Process,  Prev: Managing Global State,  Up: Making Modules Safe with Multiple Interpreters

9.19.3.2 Managing Per-Module State
..................................

To use per-module state, use *note multi-phase extension module
initialization: 4bc8.  This signals that your module supports multiple
interpreters correctly.

Set ‘PyModuleDef.m_size’ to a positive number to request that many bytes
of storage local to the module.  Usually, this will be set to the size
of some module-specific ‘struct’, which can store all of the module’s
C-level state.  In particular, it is where you should put pointers to
classes (including exceptions, but excluding static types) and settings
(e.g.  ‘csv’’s *note field_size_limit: 1937.) which the C code needs to
function.

     Note: Another option is to store state in the module’s ‘__dict__’,
     but you must avoid crashing when users modify ‘__dict__’ from
     Python code.  This usually means error- and type-checking at the C
     level, which is easy to get wrong and hard to test sufficiently.

     However, if module state is not needed in C code, storing it in
     ‘__dict__’ only is a good idea.

If the module state includes ‘PyObject’ pointers, the module object must
hold references to those objects and implement the module-level hooks
‘m_traverse’, ‘m_clear’ and ‘m_free’.  These work like ‘tp_traverse’,
‘tp_clear’ and ‘tp_free’ of a class.  Adding them will require some work
and make the code longer; this is the price for modules which can be
unloaded cleanly.

An example of a module with per-module state is currently available as
xxlimited(1); example module initialization shown at the bottom of the
file.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/blob/master/Modules/xxlimited.c


File: python.info,  Node: Opt-Out Limiting to One Module Object per Process,  Next: Module State Access from Functions,  Prev: Managing Per-Module State,  Up: Making Modules Safe with Multiple Interpreters

9.19.3.3 Opt-Out: Limiting to One Module Object per Process
...........................................................

A non-negative ‘PyModuleDef.m_size’ signals that a module supports
multiple interpreters correctly.  If this is not yet the case for your
module, you can explicitly make your module loadable only once per
process.  For example:

     // A process-wide flag
     static int loaded = 0;

     // Mutex to provide thread safety (only needed for free-threaded Python)
     static PyMutex modinit_mutex = {0};

     static int
     exec_module(PyObject* module)
     {
         PyMutex_Lock(&modinit_mutex);
         if (loaded) {
             PyMutex_Unlock(&modinit_mutex);
             PyErr_SetString(PyExc_ImportError,
                             "cannot load module more than once per process");
             return -1;
         }
         loaded = 1;
         PyMutex_Unlock(&modinit_mutex);
         // ... rest of initialization
     }

If your module’s *note PyModuleDef.m_clear: 985. function is able to
prepare for future re-initialization, it should clear the ‘loaded’ flag.
In this case, your module won’t support multiple instances existing
'concurrently', but it will, for example, support being loaded after
Python runtime shutdown (*note Py_FinalizeEx(): d3d.) and
re-initialization (*note Py_Initialize(): 8b4.).


File: python.info,  Node: Module State Access from Functions,  Prev: Opt-Out Limiting to One Module Object per Process,  Up: Making Modules Safe with Multiple Interpreters

9.19.3.4 Module State Access from Functions
...........................................

Accessing the state from module-level functions is straightforward.
Functions get the module object as their first argument; for extracting
the state, you can use ‘PyModule_GetState’:

     static PyObject *
     func(PyObject *module, PyObject *args)
     {
         my_struct *state = (my_struct*)PyModule_GetState(module);
         if (state == NULL) {
             return NULL;
         }
         // ... rest of logic
     }

     Note: ‘PyModule_GetState’ may return ‘NULL’ without setting an
     exception if there is no module state, i.e.  ‘PyModuleDef.m_size’
     was zero.  In your own module, you’re in control of ‘m_size’, so
     this is easy to prevent.


File: python.info,  Node: Heap Types<2>,  Next: Open Issues,  Prev: Making Modules Safe with Multiple Interpreters,  Up: Isolating Extension Modules

9.19.4 Heap Types
-----------------

Traditionally, types defined in C code are 'static'; that is, ‘static
PyTypeObject’ structures defined directly in code and initialized using
‘PyType_Ready()’.

Such types are necessarily shared across the process.  Sharing them
between module objects requires paying attention to any state they own
or access.  To limit the possible issues, static types are immutable at
the Python level: for example, you can’t set ‘str.myattribute = 123’.

'CPython implementation detail:' Sharing truly immutable objects between
interpreters is fine, as long as they don’t provide access to mutable
objects.  However, in CPython, every Python object has a mutable
implementation detail: the reference count.  Changes to the refcount are
guarded by the GIL. Thus, code that shares any Python objects across
interpreters implicitly depends on CPython’s current, process-wide GIL.

Because they are immutable and process-global, static types cannot
access “their” module state.  If any method of such a type requires
access to module state, the type must be converted to a 'heap-allocated
type', or 'heap type' for short.  These correspond more closely to
classes created by Python’s ‘class’ statement.

For new modules, using heap types by default is a good rule of thumb.

* Menu:

* Changing Static Types to Heap Types::
* Defining Heap Types::
* Garbage-Collection Protocol::
* Module State Access from Classes::
* Module State Access from Regular Methods::
* Module State Access from Slot Methods, Getters and Setters: Module State Access from Slot Methods Getters and Setters.
* Lifetime of the Module State::


File: python.info,  Node: Changing Static Types to Heap Types,  Next: Defining Heap Types,  Up: Heap Types<2>

9.19.4.1 Changing Static Types to Heap Types
............................................

Static types can be converted to heap types, but note that the heap type
API was not designed for “lossless” conversion from static types—that
is, creating a type that works exactly like a given static type.  So,
when rewriting the class definition in a new API, you are likely to
unintentionally change a few details (e.g.  pickleability or inherited
slots).  Always test the details that are important to you.

Watch out for the following two points in particular (but note that this
is not a comprehensive list):

   * Unlike static types, heap type objects are mutable by default.  Use
     the *note Py_TPFLAGS_IMMUTABLETYPE: 3c5. flag to prevent
     mutability.

   * Heap types inherit *note tp_new: 582. by default, so it may become
     possible to instantiate them from Python code.  You can prevent
     this with the *note Py_TPFLAGS_DISALLOW_INSTANTIATION: 585. flag.


File: python.info,  Node: Defining Heap Types,  Next: Garbage-Collection Protocol,  Prev: Changing Static Types to Heap Types,  Up: Heap Types<2>

9.19.4.2 Defining Heap Types
............................

Heap types can be created by filling a *note PyType_Spec: 1828.
structure, a description or “blueprint” of a class, and calling *note
PyType_FromModuleAndSpec(): 554. to construct a new class object.

     Note: Other functions, like *note PyType_FromSpec(): 580, can also
     create heap types, but *note PyType_FromModuleAndSpec(): 554.
     associates the module with the class, allowing access to the module
     state from methods.

The class should generally be stored in 'both' the module state (for
safe access from C) and the module’s ‘__dict__’ (for access from Python
code).


File: python.info,  Node: Garbage-Collection Protocol,  Next: Module State Access from Classes,  Prev: Defining Heap Types,  Up: Heap Types<2>

9.19.4.3 Garbage-Collection Protocol
....................................

Instances of heap types hold a reference to their type.  This ensures
that the type isn’t destroyed before all its instances are, but may
result in reference cycles that need to be broken by the garbage
collector.

To avoid memory leaks, instances of heap types must implement the
garbage collection protocol.  That is, heap types should:

   - Have the *note Py_TPFLAGS_HAVE_GC: 780. flag.

   - Define a traverse function using ‘Py_tp_traverse’, which visits the
     type (e.g.  using ‘Py_VISIT(Py_TYPE(self))’).

Please refer to the documentation of *note Py_TPFLAGS_HAVE_GC: 780. and
*note tp_traverse: 781. for additional considerations.

The API for defining heap types grew organically, leaving it somewhat
awkward to use in its current state.  The following sections will guide
you through common issues.

* Menu:

* tp_traverse in Python 3.8 and lower: tp_traverse in Python 3 8 and lower.
* Delegating tp_traverse::
* Defining tp_dealloc::
* Not overriding tp_free::
* Avoiding PyObject_New::


File: python.info,  Node: tp_traverse in Python 3 8 and lower,  Next: Delegating tp_traverse,  Up: Garbage-Collection Protocol

9.19.4.4 ‘tp_traverse’ in Python 3.8 and lower
..............................................

The requirement to visit the type from ‘tp_traverse’ was added in Python
3.9.  If you support Python 3.8 and lower, the traverse function must
'not' visit the type, so it must be more complicated:

     static int my_traverse(PyObject *self, visitproc visit, void *arg)
     {
         if (Py_Version >= 0x03090000) {
             Py_VISIT(Py_TYPE(self));
         }
         return 0;
     }

Unfortunately, *note Py_Version: 759. was only added in Python 3.11.  As
a replacement, use:

   * *note PY_VERSION_HEX: 75a, if not using the stable ABI, or

   * *note sys.version_info: 6a3. (via *note PySys_GetObject(): 38c. and
     *note PyArg_ParseTuple(): 574.).


File: python.info,  Node: Delegating tp_traverse,  Next: Defining tp_dealloc,  Prev: tp_traverse in Python 3 8 and lower,  Up: Garbage-Collection Protocol

9.19.4.5 Delegating ‘tp_traverse’
.................................

If your traverse function delegates to the *note tp_traverse: 781. of
its base class (or another type), ensure that ‘Py_TYPE(self)’ is visited
only once.  Note that only heap type are expected to visit the type in
‘tp_traverse’.

For example, if your traverse function includes:

     base->tp_traverse(self, visit, arg)

…and ‘base’ may be a static type, then it should also include:

     if (base->tp_flags & Py_TPFLAGS_HEAPTYPE) {
         // a heap type's tp_traverse already visited Py_TYPE(self)
     } else {
         if (Py_Version >= 0x03090000) {
             Py_VISIT(Py_TYPE(self));
         }
     }

It is not necessary to handle the type’s reference count in *note
tp_new: 582. and *note tp_clear: 4bac.


File: python.info,  Node: Defining tp_dealloc,  Next: Not overriding tp_free,  Prev: Delegating tp_traverse,  Up: Garbage-Collection Protocol

9.19.4.6 Defining ‘tp_dealloc’
..............................

If your type has a custom *note tp_dealloc: 4b87. function, it needs to:

   - call *note PyObject_GC_UnTrack(): 1555. before any fields are
     invalidated, and

   - decrement the reference count of the type.

To keep the type valid while ‘tp_free’ is called, the type’s refcount
needs to be decremented 'after' the instance is deallocated.  For
example:

     static void my_dealloc(PyObject *self)
     {
         PyObject_GC_UnTrack(self);
         ...
         PyTypeObject *type = Py_TYPE(self);
         type->tp_free(self);
         Py_DECREF(type);
     }

The default ‘tp_dealloc’ function does this, so if your type does 'not'
override ‘tp_dealloc’ you don’t need to add it.


File: python.info,  Node: Not overriding tp_free,  Next: Avoiding PyObject_New,  Prev: Defining tp_dealloc,  Up: Garbage-Collection Protocol

9.19.4.7 Not overriding ‘tp_free’
.................................

The *note tp_free: 4b9a. slot of a heap type must be set to *note
PyObject_GC_Del(): 1553.  This is the default; do not override it.


File: python.info,  Node: Avoiding PyObject_New,  Prev: Not overriding tp_free,  Up: Garbage-Collection Protocol

9.19.4.8 Avoiding ‘PyObject_New’
................................

GC-tracked objects need to be allocated using GC-aware functions.

If you use *note PyObject_New(): 98f. or *note PyObject_NewVar(): 990.:

   - Get and call type’s *note tp_alloc: 4b9b. slot, if possible.  That
     is, replace ‘TYPE *o = PyObject_New(TYPE, typeobj)’ with:

          TYPE *o = typeobj->tp_alloc(typeobj, 0);

     Replace ‘o = PyObject_NewVar(TYPE, typeobj, size)’ with the same,
     but use size instead of the 0.

   - If the above is not possible (e.g.  inside a custom ‘tp_alloc’),
     call *note PyObject_GC_New(): ab7. or *note PyObject_GC_NewVar():
     ab8.:

          TYPE *o = PyObject_GC_New(TYPE, typeobj);

          TYPE *o = PyObject_GC_NewVar(TYPE, typeobj, size);


File: python.info,  Node: Module State Access from Classes,  Next: Module State Access from Regular Methods,  Prev: Garbage-Collection Protocol,  Up: Heap Types<2>

9.19.4.9 Module State Access from Classes
.........................................

If you have a type object defined with *note PyType_FromModuleAndSpec():
554, you can call *note PyType_GetModule(): 978. to get the associated
module, and then *note PyModule_GetState(): 98a. to get the module’s
state.

To save a some tedious error-handling boilerplate code, you can combine
these two steps with *note PyType_GetModuleState(): 979, resulting in:

     my_struct *state = (my_struct*)PyType_GetModuleState(type);
     if (state == NULL) {
         return NULL;
     }


File: python.info,  Node: Module State Access from Regular Methods,  Next: Module State Access from Slot Methods Getters and Setters,  Prev: Module State Access from Classes,  Up: Heap Types<2>

9.19.4.10 Module State Access from Regular Methods
..................................................

Accessing the module-level state from methods of a class is somewhat
more complicated, but is possible thanks to API introduced in Python
3.9.  To get the state, you need to first get the 'defining class', and
then get the module state from it.

The largest roadblock is getting 'the class a method was defined in', or
that method’s “defining class” for short.  The defining class can have a
reference to the module it is part of.

Do not confuse the defining class with ‘Py_TYPE(self)’.  If the method
is called on a 'subclass' of your type, ‘Py_TYPE(self)’ will refer to
that subclass, which may be defined in different module than yours.

     Note: The following Python code can illustrate the concept.
     ‘Base.get_defining_class’ returns ‘Base’ even if ‘type(self) ==
     Sub’:

          class Base:
              def get_type_of_self(self):
                  return type(self)

              def get_defining_class(self):
                  return __class__

          class Sub(Base):
              pass

For a method to get its “defining class”, it must use the *note
METH_METHOD | METH_FASTCALL | METH_KEYWORDS: 17a1. *note calling
convention: 1526. and the corresponding *note PyCMethod: 767. signature:

     PyObject *PyCMethod(
         PyObject *self,               // object the method was called on
         PyTypeObject *defining_class, // defining class
         PyObject *const *args,        // C array of arguments
         Py_ssize_t nargs,             // length of "args"
         PyObject *kwnames)            // NULL, or dict of keyword arguments

Once you have the defining class, call *note PyType_GetModuleState():
979. to get the state of its associated module.

For example:

     static PyObject *
     example_method(PyObject *self,
             PyTypeObject *defining_class,
             PyObject *const *args,
             Py_ssize_t nargs,
             PyObject *kwnames)
     {
         my_struct *state = (my_struct*)PyType_GetModuleState(defining_class);
         if (state == NULL) {
             return NULL;
         }
         ... // rest of logic
     }

     PyDoc_STRVAR(example_method_doc, "...");

     static PyMethodDef my_methods[] = {
         {"example_method",
           (PyCFunction)(void(*)(void))example_method,
           METH_METHOD|METH_FASTCALL|METH_KEYWORDS,
           example_method_doc}
         {NULL},
     }


File: python.info,  Node: Module State Access from Slot Methods Getters and Setters,  Next: Lifetime of the Module State,  Prev: Module State Access from Regular Methods,  Up: Heap Types<2>

9.19.4.11 Module State Access from Slot Methods, Getters and Setters
....................................................................

     Note: This is new in Python 3.11.

Slot methods—the fast C equivalents for special methods, such as *note
nb_add: 4f96. for *note __add__: 2145. or *note tp_new: 582. for
initialization—have a very simple API that doesn’t allow passing in the
defining class, unlike with *note PyCMethod: 767.  The same goes for
getters and setters defined with *note PyGetSetDef: bd7.

To access the module state in these cases, use the *note
PyType_GetModuleByDef(): 397. function, and pass in the module
definition.  Once you have the module, call *note PyModule_GetState():
98a. to get the state:

     PyObject *module = PyType_GetModuleByDef(Py_TYPE(self), &module_def);
     my_struct *state = (my_struct*)PyModule_GetState(module);
     if (state == NULL) {
         return NULL;
     }

‘PyType_GetModuleByDef()’ works by searching the *note method resolution
order: 2339. (i.e.  all superclasses) for the first superclass that has
a corresponding module.

     Note: In very exotic cases (inheritance chains spanning multiple
     modules created from the same definition),
     ‘PyType_GetModuleByDef()’ might not return the module of the true
     defining class.  However, it will always return a module with the
     same definition, ensuring a compatible C memory layout.


File: python.info,  Node: Lifetime of the Module State,  Prev: Module State Access from Slot Methods Getters and Setters,  Up: Heap Types<2>

9.19.4.12 Lifetime of the Module State
......................................

When a module object is garbage-collected, its module state is freed.
For each pointer to (a part of) the module state, you must hold a
reference to the module object.

Usually this is not an issue, because types created with *note
PyType_FromModuleAndSpec(): 554, and their instances, hold a reference
to the module.  However, you must be careful in reference counting when
you reference module state from other places, such as callbacks for
external libraries.


File: python.info,  Node: Open Issues,  Prev: Heap Types<2>,  Up: Isolating Extension Modules

9.19.5 Open Issues
------------------

Several issues around per-module state and heap types are still open.

Discussions about improving the situation are best held on the discuss
forum under c-api tag(1).

* Menu:

* Per-Class Scope::
* Lossless Conversion to Heap Types::

   ---------- Footnotes ----------

   (1) https://discuss.python.org/c/core-dev/c-api/30


File: python.info,  Node: Per-Class Scope,  Next: Lossless Conversion to Heap Types,  Up: Open Issues

9.19.5.1 Per-Class Scope
........................

It is currently (as of Python 3.11) not possible to attach state to
individual 'types' without relying on CPython implementation details
(which may change in the future—perhaps, ironically, to allow a proper
solution for per-class scope).


File: python.info,  Node: Lossless Conversion to Heap Types,  Prev: Per-Class Scope,  Up: Open Issues

9.19.5.2 Lossless Conversion to Heap Types
..........................................

The heap type API was not designed for “lossless” conversion from static
types; that is, creating a type that works exactly like a given static
type.


File: python.info,  Node: timer file descriptor HOWTO,  Next: The Python 2 3 Method Resolution Order,  Prev: Isolating Extension Modules,  Up: Python HOWTOs

9.20 timer file descriptor HOWTO
================================


Release: 1.13

This HOWTO discusses Python’s support for the linux timer file
descriptor.

* Menu:

* Examples: Examples<40>.


File: python.info,  Node: Examples<40>,  Up: timer file descriptor HOWTO

9.20.1 Examples
---------------

The following example shows how to use a timer file descriptor to
execute a function twice a second:

     # Practical scripts should use really use a non-blocking timer,
     # we use a blocking timer here for simplicity.
     import os, time

     # Create the timer file descriptor
     fd = os.timerfd_create(time.CLOCK_REALTIME)

     # Start the timer in 1 second, with an interval of half a second
     os.timerfd_settime(fd, initial=1, interval=0.5)

     try:
         # Process timer events four times.
         for _ in range(4):
             # read() will block until the timer expires
             _ = os.read(fd, 8)
             print("Timer expired")
     finally:
         # Remember to close the timer file descriptor!
         os.close(fd)

To avoid the precision loss caused by the *note float: 2f7. type, timer
file descriptors allow specifying initial expiration and interval in
integer nanoseconds with ‘_ns’ variants of the functions.

This example shows how *note epoll(): fcd. can be used with timer file
descriptors to wait until the file descriptor is ready for reading:

     import os, time, select, socket, sys

     # Create an epoll object
     ep = select.epoll()

     # In this example, use loopback address to send "stop" command to the server.
     #
     # $ telnet 127.0.0.1 1234
     # Trying 127.0.0.1...
     # Connected to 127.0.0.1.
     # Escape character is '^]'.
     # stop
     # Connection closed by foreign host.
     #
     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     sock.bind(("127.0.0.1", 1234))
     sock.setblocking(False)
     sock.listen(1)
     ep.register(sock, select.EPOLLIN)

     # Create timer file descriptors in non-blocking mode.
     num = 3
     fds = []
     for _ in range(num):
         fd = os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK)
         fds.append(fd)
         # Register the timer file descriptor for read events
         ep.register(fd, select.EPOLLIN)

     # Start the timer with os.timerfd_settime_ns() in nanoseconds.
     # Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc
     for i, fd in enumerate(fds, start=1):
         one_sec_in_nsec = 10**9
         i = i * one_sec_in_nsec
         os.timerfd_settime_ns(fd, initial=i//4, interval=i//4)

     timeout = 3
     try:
         conn = None
         is_active = True
         while is_active:
             # Wait for the timer to expire for 3 seconds.
             # epoll.poll() returns a list of (fd, event) pairs.
             # fd is a file descriptor.
             # sock and conn[=returned value of socket.accept()] are socket objects, not file descriptors.
             # So use sock.fileno() and conn.fileno() to get the file descriptors.
             events = ep.poll(timeout)

             # If more than one timer file descriptors are ready for reading at once,
             # epoll.poll() returns a list of (fd, event) pairs.
             #
             # In this example settings,
             #    1st timer fires every 0.25 seconds in 0.25 seconds. (0.25, 0.5, 0.75, 1.0, ...)
             #    2nd timer every 0.5 seconds in 0.5 seconds. (0.5, 1.0, 1.5, 2.0, ...)
             #    3rd timer every 0.75 seconds in 0.75 seconds. (0.75, 1.5, 2.25, 3.0, ...)
             #
             #    In 0.25 seconds, only 1st timer fires.
             #    In 0.5 seconds, 1st timer and 2nd timer fires at once.
             #    In 0.75 seconds, 1st timer and 3rd timer fires at once.
             #    In 1.5 seconds, 1st timer, 2nd timer and 3rd timer fires at once.
             #
             # If a timer file descriptor is signaled more than once since
             # the last os.read() call, os.read() returns the number of signaled
             # as host order of class bytes.
             print(f"Signaled events={events}")
             for fd, event in events:
                 if event & select.EPOLLIN:
                     if fd == sock.fileno():
                         # Check if there is a connection request.
                         print(f"Accepting connection {fd}")
                         conn, addr = sock.accept()
                         conn.setblocking(False)
                         print(f"Accepted connection {conn} from {addr}")
                         ep.register(conn, select.EPOLLIN)
                     elif conn and fd == conn.fileno():
                         # Check if there is data to read.
                         print(f"Reading data {fd}")
                         data = conn.recv(1024)
                         if data:
                             # You should catch UnicodeDecodeError exception for safety.
                             cmd = data.decode()
                             if cmd.startswith("stop"):
                                 print(f"Stopping server")
                                 is_active = False
                             else:
                                 print(f"Unknown command: {cmd}")
                         else:
                             # No more data, close connection
                             print(f"Closing connection {fd}")
                             ep.unregister(conn)
                             conn.close()
                             conn = None
                     elif fd in fds:
                         print(f"Reading timer {fd}")
                         count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder)
                         print(f"Timer {fds.index(fd) + 1} expired {count} times")
                     else:
                         print(f"Unknown file descriptor {fd}")
     finally:
         for fd in fds:
             ep.unregister(fd)
             os.close(fd)
         ep.close()

This example shows how *note select(): dce. can be used with timer file
descriptors to wait until the file descriptor is ready for reading:

     import os, time, select, socket, sys

     # In this example, use loopback address to send "stop" command to the server.
     #
     # $ telnet 127.0.0.1 1234
     # Trying 127.0.0.1...
     # Connected to 127.0.0.1.
     # Escape character is '^]'.
     # stop
     # Connection closed by foreign host.
     #
     sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
     sock.bind(("127.0.0.1", 1234))
     sock.setblocking(False)
     sock.listen(1)

     # Create timer file descriptors in non-blocking mode.
     num = 3
     fds = [os.timerfd_create(time.CLOCK_REALTIME, flags=os.TFD_NONBLOCK)
            for _ in range(num)]
     select_fds = fds + [sock]

     # Start the timers with os.timerfd_settime() in seconds.
     # Timer 1 fires every 0.25 seconds; timer 2 every 0.5 seconds; etc
     for i, fd in enumerate(fds, start=1):
        os.timerfd_settime(fd, initial=i/4, interval=i/4)

     timeout = 3
     try:
         conn = None
         is_active = True
         while is_active:
            # Wait for the timer to expire for 3 seconds.
            # select.select() returns a list of file descriptors or objects.
            rfd, wfd, xfd = select.select(select_fds, select_fds, select_fds, timeout)
            for fd in rfd:
                if fd == sock:
                    # Check if there is a connection request.
                    print(f"Accepting connection {fd}")
                    conn, addr = sock.accept()
                    conn.setblocking(False)
                    print(f"Accepted connection {conn} from {addr}")
                    select_fds.append(conn)
                elif conn and fd == conn:
                    # Check if there is data to read.
                    print(f"Reading data {fd}")
                    data = conn.recv(1024)
                    if data:
                        # You should catch UnicodeDecodeError exception for safety.
                        cmd = data.decode()
                        if cmd.startswith("stop"):
                            print(f"Stopping server")
                            is_active = False
                        else:
                            print(f"Unknown command: {cmd}")
                    else:
                        # No more data, close connection
                        print(f"Closing connection {fd}")
                        select_fds.remove(conn)
                        conn.close()
                        conn = None
                elif fd in fds:
                    print(f"Reading timer {fd}")
                    count = int.from_bytes(os.read(fd, 8), byteorder=sys.byteorder)
                    print(f"Timer {fds.index(fd) + 1} expired {count} times")
                else:
                    print(f"Unknown file descriptor {fd}")
     finally:
         for fd in fds:
            os.close(fd)
         sock.close()
         sock = None


File: python.info,  Node: The Python 2 3 Method Resolution Order,  Next: Python experimental support for free threading,  Prev: timer file descriptor HOWTO,  Up: Python HOWTOs

9.21 The Python 2.3 Method Resolution Order
===========================================

     Note: This is a historical document, provided as an appendix to the
     official documentation.  The Method Resolution Order discussed here
     was 'introduced' in Python 2.3, but it is still used in later
     versions – including Python 3.

By Michele Simionato(1).


Abstract: 'This document is intended for Python programmers who want to
understand the C3 Method Resolution Order used in Python 2.3.  Although
it is not intended for newbies, it is quite pedagogical with many worked
out examples.  I am not aware of other publicly available documents with
the same scope, therefore it should be useful.'

Disclaimer:

     'I donate this document to the Python Software Foundation, under
     the Python 2.3 license.  As usual in these circumstances, I warn
     the reader that what follows' should 'be correct, but I don’t give
     any warranty.  Use it at your own risk and peril!'

Acknowledgments:

     'All the people of the Python mailing list who sent me their
     support.  Paul Foley who pointed out various imprecisions and made
     me to add the part on local precedence ordering.  David Goodger for
     help with the formatting in reStructuredText.  David Mertz for help
     with the editing.  Finally, Guido van Rossum who enthusiastically
     added this document to the official Python 2.3 home-page.'

* Menu:

* The beginning::
* The C3 Method Resolution Order::
* Examples: Examples<41>.
* Bad Method Resolution Orders::
* The end::
* Resources::

   ---------- Footnotes ----------

   (1) https://www.phyast.pitt.edu/~micheles/


File: python.info,  Node: The beginning,  Next: The C3 Method Resolution Order,  Up: The Python 2 3 Method Resolution Order

9.21.1 The beginning
--------------------

     'Felix qui potuit rerum cognoscere causas' – Virgilius

Everything started with a post by Samuele Pedroni to the Python
development mailing list (1).  In his post, Samuele showed that the
Python 2.2 method resolution order is not monotonic and he proposed to
replace it with the C3 method resolution order.  Guido agreed with his
arguments and therefore now Python 2.3 uses C3.  The C3 method itself
has nothing to do with Python, since it was invented by people working
on Dylan and it is described in a paper intended for lispers (2).  The
present paper gives a (hopefully) readable discussion of the C3
algorithm for Pythonistas who want to understand the reasons for the
change.

First of all, let me point out that what I am going to say only applies
to the 'new style classes' introduced in Python 2.2: 'classic classes'
maintain their old method resolution order, depth first and then left to
right.  Therefore, there is no breaking of old code for classic classes;
and even if in principle there could be breaking of code for Python 2.2
new style classes, in practice the cases in which the C3 resolution
order differs from the Python 2.2 method resolution order are so rare
that no real breaking of code is expected.  Therefore:

     'Don’t be scared!'

Moreover, unless you make strong use of multiple inheritance and you
have non-trivial hierarchies, you don’t need to understand the C3
algorithm, and you can easily skip this paper.  On the other hand, if
you really want to know how multiple inheritance works, then this paper
is for you.  The good news is that things are not as complicated as you
might expect.

Let me begin with some basic definitions.

  1. Given a class C in a complicated multiple inheritance hierarchy, it
     is a non-trivial task to specify the order in which methods are
     overridden, i.e.  to specify the order of the ancestors of C.

  2. The list of the ancestors of a class C, including the class itself,
     ordered from the nearest ancestor to the furthest, is called the
     class precedence list or the 'linearization' of C.

  3. The 'Method Resolution Order' (MRO) is the set of rules that
     construct the linearization.  In the Python literature, the idiom
     “the MRO of C” is also used as a synonymous for the linearization
     of the class C.

  4. For instance, in the case of single inheritance hierarchy, if C is
     a subclass of C1, and C1 is a subclass of C2, then the
     linearization of C is simply the list [C, C1 , C2].  However, with
     multiple inheritance hierarchies, the construction of the
     linearization is more cumbersome, since it is more difficult to
     construct a linearization that respects 'local precedence ordering'
     and 'monotonicity'.

  5. I will discuss the local precedence ordering later, but I can give
     the definition of monotonicity here.  A MRO is monotonic when the
     following is true: 'if C1 precedes C2 in the linearization of C,
     then C1 precedes C2 in the linearization of any subclass of C'.
     Otherwise, the innocuous operation of deriving a new class could
     change the resolution order of methods, potentially introducing
     very subtle bugs.  Examples where this happens will be shown later.

  6. Not all classes admit a linearization.  There are cases, in
     complicated hierarchies, where it is not possible to derive a class
     such that its linearization respects all the desired properties.

Here I give an example of this situation.  Consider the hierarchy

     >>> O = object
     >>> class X(O): pass
     >>> class Y(O): pass
     >>> class A(X,Y): pass
     >>> class B(Y,X): pass

which can be represented with the following inheritance graph, where I
have denoted with O the ‘object’ class, which is the beginning of any
hierarchy for new style classes:

           -----------
          |           |
          |    O      |
          |  /   \    |
           - X    Y  /
             |  / | /
             | /  |/
             A    B
             \   /
               ?

In this case, it is not possible to derive a new class C from A and B,
since X precedes Y in A, but Y precedes X in B, therefore the method
resolution order would be ambiguous in C.

Python 2.3 raises an exception in this situation (TypeError: MRO
conflict among bases Y, X) forbidding the naive programmer from creating
ambiguous hierarchies.  Python 2.2 instead does not raise an exception,
but chooses an 'ad hoc' ordering (CABXYO in this case).

   ---------- Footnotes ----------

   (1) The thread on python-dev started by Samuele Pedroni:
‘https://mail.python.org/pipermail/python-dev/2002-October/029035.html’

   (2) The paper 'A Monotonic Superclass Linearization for Dylan':
‘https://doi.org/10.1145/236337.236343’


File: python.info,  Node: The C3 Method Resolution Order,  Next: Examples<41>,  Prev: The beginning,  Up: The Python 2 3 Method Resolution Order

9.21.2 The C3 Method Resolution Order
-------------------------------------

Let me introduce a few simple notations which will be useful for the
following discussion.  I will use the shortcut notation:

     C1 C2 ... CN

to indicate the list of classes [C1, C2, … , CN].

The 'head' of the list is its first element:

     head = C1

whereas the 'tail' is the rest of the list:

     tail = C2 ... CN.

I shall also use the notation:

     C + (C1 C2 ... CN) = C C1 C2 ... CN

to denote the sum of the lists [C] + [C1, C2, … ,CN].

Now I can explain how the MRO works in Python 2.3.

Consider a class C in a multiple inheritance hierarchy, with C
inheriting from the base classes B1, B2, … , BN. We want to compute the
linearization L[C] of the class C. The rule is the following:

     'the linearization of C is the sum of C plus the merge of the
     linearizations of the parents and the list of the parents.'

In symbolic notation:

     L[C(B1 ... BN)] = C + merge(L[B1] ... L[BN], B1 ... BN)

In particular, if C is the ‘object’ class, which has no parents, the
linearization is trivial:

     L[object] = object.

However, in general one has to compute the merge according to the
following prescription:

     'take the head of the first list, i.e L[B1][0]; if this head is not
     in the tail of any of the other lists, then add it to the
     linearization of C and remove it from the lists in the merge,
     otherwise look at the head of the next list and take it, if it is a
     good head.  Then repeat the operation until all the class are
     removed or it is impossible to find good heads.  In this case, it
     is impossible to construct the merge, Python 2.3 will refuse to
     create the class C and will raise an exception.'

This prescription ensures that the merge operation 'preserves' the
ordering, if the ordering can be preserved.  On the other hand, if the
order cannot be preserved (as in the example of serious order
disagreement discussed above) then the merge cannot be computed.

The computation of the merge is trivial if C has only one parent (single
inheritance); in this case:

     L[C(B)] = C + merge(L[B],B) = C + L[B]

However, in the case of multiple inheritance things are more cumbersome
and I don’t expect you can understand the rule without a couple of
examples ;-)


File: python.info,  Node: Examples<41>,  Next: Bad Method Resolution Orders,  Prev: The C3 Method Resolution Order,  Up: The Python 2 3 Method Resolution Order

9.21.3 Examples
---------------

First example.  Consider the following hierarchy:

     >>> O = object
     >>> class F(O): pass
     >>> class E(O): pass
     >>> class D(O): pass
     >>> class C(D,F): pass
     >>> class B(D,E): pass
     >>> class A(B,C): pass

In this case the inheritance graph can be drawn as:

                                    6
                                   ---
          Level 3                 | O |                  (more general)
                                /  ---  \
                               /    |    \                      |
                              /     |     \                     |
                             /      |      \                    |
                            ---    ---    ---                   |
          Level 2        3 | D | 4| E |  | F | 5                |
                            ---    ---    ---                   |
                             \  \ _ /       |                   |
                              \    / \ _    |                   |
                               \  /      \  |                   |
                                ---      ---                    |
          Level 1            1 | B |    | C | 2                 |
                                ---      ---                    |
                                  \      /                      |
                                   \    /                      \ /
                                     ---
          Level 0                 0 | A |                (more specialized)
                                     ---

The linearizations of O,D,E and F are trivial:

     L[O] = O
     L[D] = D O
     L[E] = E O
     L[F] = F O

The linearization of B can be computed as:

     L[B] = B + merge(DO, EO, DE)

We see that D is a good head, therefore we take it and we are reduced to
compute ‘merge(O,EO,E)’.  Now O is not a good head, since it is in the
tail of the sequence EO. In this case the rule says that we have to skip
to the next sequence.  Then we see that E is a good head; we take it and
we are reduced to compute ‘merge(O,O)’ which gives O. Therefore:

     L[B] =  B D E O

Using the same procedure one finds:

     L[C] = C + merge(DO,FO,DF)
          = C + D + merge(O,FO,F)
          = C + D + F + merge(O,O)
          = C D F O

Now we can compute:

     L[A] = A + merge(BDEO,CDFO,BC)
          = A + B + merge(DEO,CDFO,C)
          = A + B + C + merge(DEO,DFO)
          = A + B + C + D + merge(EO,FO)
          = A + B + C + D + E + merge(O,FO)
          = A + B + C + D + E + F + merge(O,O)
          = A B C D E F O

In this example, the linearization is ordered in a pretty nice way
according to the inheritance level, in the sense that lower levels (i.e.
more specialized classes) have higher precedence (see the inheritance
graph).  However, this is not the general case.

I leave as an exercise for the reader to compute the linearization for
my second example:

     >>> O = object
     >>> class F(O): pass
     >>> class E(O): pass
     >>> class D(O): pass
     >>> class C(D,F): pass
     >>> class B(E,D): pass
     >>> class A(B,C): pass

The only difference with the previous example is the change B(D,E) –>
B(E,D); however even such a little modification completely changes the
ordering of the hierarchy:

                                     6
                                    ---
          Level 3                  | O |
                                 /  ---  \
                                /    |    \
                               /     |     \
                              /      |      \
                            ---     ---    ---
          Level 2        2 | E | 4 | D |  | F | 5
                            ---     ---    ---
                             \      / \     /
                              \    /   \   /
                               \  /     \ /
                                ---     ---
          Level 1            1 | B |   | C | 3
                                ---     ---
                                 \       /
                                  \     /
                                    ---
          Level 0                0 | A |
                                    ---

Notice that the class E, which is in the second level of the hierarchy,
precedes the class C, which is in the first level of the hierarchy, i.e.
E is more specialized than C, even if it is in a higher level.

A lazy programmer can obtain the MRO directly from Python 2.2, since in
this case it coincides with the Python 2.3 linearization.  It is enough
to invoke the *note mro(): 20dc. method of class A:

     >>> A.mro()
     [<class 'A'>, <class 'B'>, <class 'E'>,
     <class 'C'>, <class 'D'>, <class 'F'>,
     <class 'object'>]

Finally, let me consider the example discussed in the first section,
involving a serious order disagreement.  In this case, it is
straightforward to compute the linearizations of O, X, Y, A and B:

          L[O] = 0
          L[X] = X O
          L[Y] = Y O
          L[A] = A X Y O
          L[B] = B Y X O

However, it is impossible to compute the linearization for a class C
that inherits from A and B:

     L[C] = C + merge(AXYO, BYXO, AB)
          = C + A + merge(XYO, BYXO, B)
          = C + A + B + merge(XYO, YXO)

At this point we cannot merge the lists XYO and YXO, since X is in the
tail of YXO whereas Y is in the tail of XYO: therefore there are no good
heads and the C3 algorithm stops.  Python 2.3 raises an error and
refuses to create the class C.


File: python.info,  Node: Bad Method Resolution Orders,  Next: The end,  Prev: Examples<41>,  Up: The Python 2 3 Method Resolution Order

9.21.4 Bad Method Resolution Orders
-----------------------------------

A MRO is 'bad' when it breaks such fundamental properties as local
precedence ordering and monotonicity.  In this section, I will show that
both the MRO for classic classes and the MRO for new style classes in
Python 2.2 are bad.

It is easier to start with the local precedence ordering.  Consider the
following example:

     >>> F=type('Food',(),{'remember2buy':'spam'})
     >>> E=type('Eggs',(F,),{'remember2buy':'eggs'})
     >>> G=type('GoodFood',(F,E),{}) # under Python 2.3 this is an error!

with inheritance diagram

                       O
                       |
          (buy spam)   F
                       | \
                       | E   (buy eggs)
                       | /
                       G

                (buy eggs or spam ?)

We see that class G inherits from F and E, with F 'before' E: therefore
we would expect the attribute 'G.remember2buy' to be inherited by
'F.remember2buy' and not by 'E.remember2buy': nevertheless Python 2.2
gives

     >>> G.remember2buy
     'eggs'

This is a breaking of local precedence ordering since the order in the
local precedence list, i.e.  the list of the parents of G, is not
preserved in the Python 2.2 linearization of G:

     L[G,P22]= G E F object   # F *follows* E

One could argue that the reason why F follows E in the Python 2.2
linearization is that F is less specialized than E, since F is the
superclass of E; nevertheless the breaking of local precedence ordering
is quite non-intuitive and error prone.  This is particularly true since
it is a different from old style classes:

     >>> class F: remember2buy='spam'
     >>> class E(F): remember2buy='eggs'
     >>> class G(F,E): pass
     >>> G.remember2buy
     'spam'

In this case the MRO is GFEF and the local precedence ordering is
preserved.

As a general rule, hierarchies such as the previous one should be
avoided, since it is unclear if F should override E or vice-versa.
Python 2.3 solves the ambiguity by raising an exception in the creation
of class G, effectively stopping the programmer from generating
ambiguous hierarchies.  The reason for that is that the C3 algorithm
fails when the merge:

     merge(FO,EFO,FE)

cannot be computed, because F is in the tail of EFO and E is in the tail
of FE.

The real solution is to design a non-ambiguous hierarchy, i.e.  to
derive G from E and F (the more specific first) and not from F and E; in
this case the MRO is GEF without any doubt.

                     O
                     |
                     F (spam)
                   / |
          (eggs)   E |
                   \ |
                     G
                       (eggs, no doubt)

Python 2.3 forces the programmer to write good hierarchies (or, at
least, less error-prone ones).

On a related note, let me point out that the Python 2.3 algorithm is
smart enough to recognize obvious mistakes, as the duplication of
classes in the list of parents:

     >>> class A(object): pass
     >>> class C(A,A): pass # error
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     TypeError: duplicate base class A

Python 2.2 (both for classic classes and new style classes) in this
situation, would not raise any exception.

Finally, I would like to point out two lessons we have learned from this
example:

  1. despite the name, the MRO determines the resolution order of
     attributes, not only of methods;

  2. the default food for Pythonistas is spam !  (but you already knew
     that ;-)

Having discussed the issue of local precedence ordering, let me now
consider the issue of monotonicity.  My goal is to show that neither the
MRO for classic classes nor that for Python 2.2 new style classes is
monotonic.

To prove that the MRO for classic classes is non-monotonic is rather
trivial, it is enough to look at the diamond diagram:

             C
            / \
           /   \
          A     B
           \   /
            \ /
             D

One easily discerns the inconsistency:

     L[B,P21] = B C        # B precedes C : B's methods win
     L[D,P21] = D A C B C  # B follows C  : C's methods win!

On the other hand, there are no problems with the Python 2.2 and 2.3
MROs, they give both:

     L[D] = D A B C

Guido points out in his essay (1) that the classic MRO is not so bad in
practice, since one can typically avoids diamonds for classic classes.
But all new style classes inherit from ‘object’, therefore diamonds are
unavoidable and inconsistencies shows up in every multiple inheritance
graph.

The MRO of Python 2.2 makes breaking monotonicity difficult, but not
impossible.  The following example, originally provided by Samuele
Pedroni, shows that the MRO of Python 2.2 is non-monotonic:

     >>> class A(object): pass
     >>> class B(object): pass
     >>> class C(object): pass
     >>> class D(object): pass
     >>> class E(object): pass
     >>> class K1(A,B,C): pass
     >>> class K2(D,B,E): pass
     >>> class K3(D,A):   pass
     >>> class Z(K1,K2,K3): pass

Here are the linearizations according to the C3 MRO (the reader should
verify these linearizations as an exercise and draw the inheritance
diagram ;-)

     L[A] = A O
     L[B] = B O
     L[C] = C O
     L[D] = D O
     L[E] = E O
     L[K1]= K1 A B C O
     L[K2]= K2 D B E O
     L[K3]= K3 D A O
     L[Z] = Z K1 K2 K3 D A B C E O

Python 2.2 gives exactly the same linearizations for A, B, C, D, E, K1,
K2 and K3, but a different linearization for Z:

     L[Z,P22] = Z K1 K3 A K2 D B C E O

It is clear that this linearization is 'wrong', since A comes before D
whereas in the linearization of K3 A comes 'after' D. In other words, in
K3 methods derived by D override methods derived by A, but in Z, which
still is a subclass of K3, methods derived by A override methods derived
by D! This is a violation of monotonicity.  Moreover, the Python 2.2
linearization of Z is also inconsistent with local precedence ordering,
since the local precedence list of the class Z is [K1, K2, K3] (K2
precedes K3), whereas in the linearization of Z K2 'follows' K3.  These
problems explain why the 2.2 rule has been dismissed in favor of the C3
rule.

   ---------- Footnotes ----------

   (1) Guido van Rossum’s essay, 'Unifying types and classes in Python
2.2':
‘https://web.archive.org/web/20140210194412/http://www.python.org/download/releases/2.2.2/descrintro’


File: python.info,  Node: The end,  Next: Resources,  Prev: Bad Method Resolution Orders,  Up: The Python 2 3 Method Resolution Order

9.21.5 The end
--------------

This section is for the impatient reader, who skipped all the previous
sections and jumped immediately to the end.  This section is for the
lazy programmer too, who didn’t want to exercise her/his brain.
Finally, it is for the programmer with some hubris, otherwise s/he would
not be reading a paper on the C3 method resolution order in multiple
inheritance hierarchies ;-) These three virtues taken all together (and
'not' separately) deserve a prize: the prize is a short Python 2.2
script that allows you to compute the 2.3 MRO without risk to your
brain.  Simply change the last line to play with the various examples I
have discussed in this paper.:

     #<mro.py>

     """C3 algorithm by Samuele Pedroni (with readability enhanced by me)."""

     class __metaclass__(type):
         "All classes are metamagically modified to be nicely printed"
         __repr__ = lambda cls: cls.__name__

     class ex_2:
         "Serious order disagreement" #From Guido
         class O: pass
         class X(O): pass
         class Y(O): pass
         class A(X,Y): pass
         class B(Y,X): pass
         try:
             class Z(A,B): pass #creates Z(A,B) in Python 2.2
         except TypeError:
             pass # Z(A,B) cannot be created in Python 2.3

     class ex_5:
         "My first example"
         class O: pass
         class F(O): pass
         class E(O): pass
         class D(O): pass
         class C(D,F): pass
         class B(D,E): pass
         class A(B,C): pass

     class ex_6:
         "My second example"
         class O: pass
         class F(O): pass
         class E(O): pass
         class D(O): pass
         class C(D,F): pass
         class B(E,D): pass
         class A(B,C): pass

     class ex_9:
         "Difference between Python 2.2 MRO and C3" #From Samuele
         class O: pass
         class A(O): pass
         class B(O): pass
         class C(O): pass
         class D(O): pass
         class E(O): pass
         class K1(A,B,C): pass
         class K2(D,B,E): pass
         class K3(D,A): pass
         class Z(K1,K2,K3): pass

     def merge(seqs):
         print '\n\nCPL[%s]=%s' % (seqs[0][0],seqs),
         res = []; i=0
         while 1:
           nonemptyseqs=[seq for seq in seqs if seq]
           if not nonemptyseqs: return res
           i+=1; print '\n',i,'round: candidates...',
           for seq in nonemptyseqs: # find merge candidates among seq heads
               cand = seq[0]; print ' ',cand,
               nothead=[s for s in nonemptyseqs if cand in s[1:]]
               if nothead: cand=None #reject candidate
               else: break
           if not cand: raise "Inconsistent hierarchy"
           res.append(cand)
           for seq in nonemptyseqs: # remove cand
               if seq[0] == cand: del seq[0]

     def mro(C):
         "Compute the class precedence list (mro) according to C3"
         return merge([[C]]+map(mro,C.__bases__)+[list(C.__bases__)])

     def print_mro(C):
         print '\nMRO[%s]=%s' % (C,mro(C))
         print '\nP22 MRO[%s]=%s' % (C,C.mro())

     print_mro(ex_9.Z)

     #</mro.py>

That’s all folks,

     enjoy !


File: python.info,  Node: Resources,  Prev: The end,  Up: The Python 2 3 Method Resolution Order

9.21.6 Resources
----------------


File: python.info,  Node: Python experimental support for free threading,  Next: C API Extension Support for Free Threading,  Prev: The Python 2 3 Method Resolution Order,  Up: Python HOWTOs

9.22 Python experimental support for free threading
===================================================

Starting with the 3.13 release, CPython has experimental support for a
build of Python called *note free threading: 15b3. where the *note
global interpreter lock: 148. (GIL) is disabled.  Free-threaded
execution allows for full utilization of the available processing power
by running threads in parallel on available CPU cores.  While not all
software will benefit from this automatically, programs designed with
threading in mind will run faster on multi-core hardware.

'The free-threaded mode is experimental' and work is ongoing to improve
it: expect some bugs and a substantial single-threaded performance hit.

This document describes the implications of free threading for Python
code.  See *note C API Extension Support for Free Threading: 54f4. for
information on how to write C extensions that support the free-threaded
build.

See also
........

PEP 703(1) – Making the Global Interpreter Lock Optional in CPython for
an overall description of free-threaded Python.

* Menu:

* Installation::
* Identifying free-threaded Python::
* The global interpreter lock in free-threaded Python::
* Thread safety::
* Known limitations::

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/


File: python.info,  Node: Installation,  Next: Identifying free-threaded Python,  Up: Python experimental support for free threading

9.22.1 Installation
-------------------

Starting with Python 3.13, the official macOS and Windows installers
optionally support installing free-threaded Python binaries.  The
installers are available at ‘https://www.python.org/downloads/’.

For information on other platforms, see the Installing a Free-Threaded
Python(1), a community-maintained installation guide for installing
free-threaded Python.

When building CPython from source, the *note -disable-gil: 174.
configure option should be used to build a free-threaded Python
interpreter.

   ---------- Footnotes ----------

   (1) https://py-free-threading.github.io/installing-cpython/


File: python.info,  Node: Identifying free-threaded Python,  Next: The global interpreter lock in free-threaded Python,  Prev: Installation,  Up: Python experimental support for free threading

9.22.2 Identifying free-threaded Python
---------------------------------------

To check if the current interpreter supports free-threading, *note
python -VV: 177. and *note sys.version: 178. contain “experimental
free-threading build”.  The new *note sys._is_gil_enabled(): 45ec.
function can be used to check whether the GIL is actually disabled in
the running process.

The ‘sysconfig.get_config_var("Py_GIL_DISABLED")’ configuration variable
can be used to determine whether the build supports free threading.  If
the variable is set to ‘1’, then the build supports free threading.
This is the recommended mechanism for decisions related to the build
configuration.


File: python.info,  Node: The global interpreter lock in free-threaded Python,  Next: Thread safety,  Prev: Identifying free-threaded Python,  Up: Python experimental support for free threading

9.22.3 The global interpreter lock in free-threaded Python
----------------------------------------------------------

Free-threaded builds of CPython support optionally running with the GIL
enabled at runtime using the environment variable *note PYTHON_GIL: 175.
or the command-line option *note -X gil: 176.

The GIL may also automatically be enabled when importing a C-API
extension module that is not explicitly marked as supporting free
threading.  A warning will be printed in this case.

In addition to individual package documentation, the following websites
track the status of popular packages support for free threading:

   * ‘https://py-free-threading.github.io/tracking/’

   * ‘https://hugovk.github.io/free-threaded-wheels/’


File: python.info,  Node: Thread safety,  Next: Known limitations,  Prev: The global interpreter lock in free-threaded Python,  Up: Python experimental support for free threading

9.22.4 Thread safety
--------------------

The free-threaded build of CPython aims to provide similar thread-safety
behavior at the Python level to the default GIL-enabled build.  Built-in
types like *note dict: 256, *note list: 614, and *note set: 5dc. use
internal locks to protect against concurrent modifications in ways that
behave similarly to the GIL. However, Python has not historically
guaranteed specific behavior for concurrent modifications to these
built-in types, so this should be treated as a description of the
current implementation, not a guarantee of current or future behavior.

     Note: It’s recommended to use the *note threading.Lock: 178a. or
     other synchronization primitives instead of relying on the internal
     locks of built-in types, when possible.


File: python.info,  Node: Known limitations,  Prev: Thread safety,  Up: Python experimental support for free threading

9.22.5 Known limitations
------------------------

This section describes known limitations of the free-threaded CPython
build.

* Menu:

* Immortalization::
* Frame objects: Frame objects<2>.
* Iterators: Iterators<3>.
* Single-threaded performance::


File: python.info,  Node: Immortalization,  Next: Frame objects<2>,  Up: Known limitations

9.22.5.1 Immortalization
........................

The free-threaded build of the 3.13 release makes some objects *note
immortal: 45dd.  Immortal objects are not deallocated and have reference
counts that are never modified.  This is done to avoid reference count
contention that would prevent efficient multi-threaded scaling.

An object will be made immortal when a new thread is started for the
first time after the main thread is running.  The following objects are
immortalized:

   * *note function: 299. objects declared at the module level

   * *note method: 1e5f. descriptors

   * *note code: 1d2. objects

   * *note module: 1772. objects and their dictionaries

   * *note classes: 20bd. (type objects)

Because immortal objects are never deallocated, applications that create
many objects of these types may see increased memory usage.  This is
expected to be addressed in the 3.14 release.

Additionally, numeric and string literals in the code as well as strings
returned by *note sys.intern(): 1323. are also immortalized.  This
behavior is expected to remain in the 3.14 free-threaded build.


File: python.info,  Node: Frame objects<2>,  Next: Iterators<3>,  Prev: Immortalization,  Up: Known limitations

9.22.5.2 Frame objects
......................

It is not safe to access *note frame: 6e3. objects from other threads
and doing so may cause your program to crash .  This means that *note
sys._current_frames(): 1481. is generally not safe to use in a
free-threaded build.  Functions like *note inspect.currentframe(): 6e5.
and *note sys._getframe(): 6e4. are generally safe as long as the
resulting frame object is not passed to another thread.


File: python.info,  Node: Iterators<3>,  Next: Single-threaded performance,  Prev: Frame objects<2>,  Up: Known limitations

9.22.5.3 Iterators
..................

Sharing the same iterator object between multiple threads is generally
not safe and threads may see duplicate or missing elements when
iterating or crash the interpreter.


File: python.info,  Node: Single-threaded performance,  Prev: Iterators<3>,  Up: Known limitations

9.22.5.4 Single-threaded performance
....................................

The free-threaded build has additional overhead when executing Python
code compared to the default GIL-enabled build.  In 3.13, this overhead
is about 40% on the pyperformance(1) suite.  Programs that spend most of
their time in C extensions or I/O will see less of an impact.  The
largest impact is because the specializing adaptive interpreter ( PEP
659(2)) is disabled in the free-threaded build.  We expect to re-enable
it in a thread-safe way in the 3.14 release.  This overhead is expected
to be reduced in upcoming Python release.  We are aiming for an overhead
of 10% or less on the pyperformance suite compared to the default
GIL-enabled build.

   ---------- Footnotes ----------

   (1) https://pyperformance.readthedocs.io/

   (2) https://peps.python.org/pep-0659/


File: python.info,  Node: C API Extension Support for Free Threading,  Prev: Python experimental support for free threading,  Up: Python HOWTOs

9.23 C API Extension Support for Free Threading
===============================================

Starting with the 3.13 release, CPython has experimental support for
running with the *note global interpreter lock: 148. (GIL) disabled in a
configuration called *note free threading: 15b3.  This document
describes how to adapt C API extensions to support free threading.

* Menu:

* Identifying the Free-Threaded Build in C::
* Module Initialization::
* General API Guidelines::
* Borrowed References::
* Memory Allocation APIs::
* Thread State and GIL APIs::
* Protecting Internal Extension State::
* Building Extensions for the Free-Threaded Build::


File: python.info,  Node: Identifying the Free-Threaded Build in C,  Next: Module Initialization,  Up: C API Extension Support for Free Threading

9.23.1 Identifying the Free-Threaded Build in C
-----------------------------------------------

The CPython C API exposes the ‘Py_GIL_DISABLED’ macro: in the
free-threaded build it’s defined to ‘1’, and in the regular build it’s
not defined.  You can use it to enable code that only runs under the
free-threaded build:

     #ifdef Py_GIL_DISABLED
     /* code that only runs in the free-threaded build */
     #endif

     Note: On Windows, this macro is not defined automatically, but must
     be specified to the compiler when building.  The *note
     sysconfig.get_config_var(): 1068. function can be used to determine
     whether the current running interpreter had the macro defined.


File: python.info,  Node: Module Initialization,  Next: General API Guidelines,  Prev: Identifying the Free-Threaded Build in C,  Up: C API Extension Support for Free Threading

9.23.2 Module Initialization
----------------------------

Extension modules need to explicitly indicate that they support running
with the GIL disabled; otherwise importing the extension will raise a
warning and enable the GIL at runtime.

There are two ways to indicate that an extension module supports running
with the GIL disabled depending on whether the extension uses
multi-phase or single-phase initialization.

* Menu:

* Multi-Phase Initialization::
* Single-Phase Initialization::


File: python.info,  Node: Multi-Phase Initialization,  Next: Single-Phase Initialization,  Up: Module Initialization

9.23.2.1 Multi-Phase Initialization
...................................

Extensions that use multi-phase initialization (i.e., *note
PyModuleDef_Init(): 4b6d.) should add a *note Py_mod_gil: 158. slot in
the module definition.  If your extension supports older versions of
CPython, you should guard the slot with a *note PY_VERSION_HEX: 75a.
check.

     static struct PyModuleDef_Slot module_slots[] = {
         ...
     #if PY_VERSION_HEX >= 0x030D0000
         {Py_mod_gil, Py_MOD_GIL_NOT_USED},
     #endif
         {0, NULL}
     };

     static struct PyModuleDef moduledef = {
         PyModuleDef_HEAD_INIT,
         .m_slots = module_slots,
         ...
     };


File: python.info,  Node: Single-Phase Initialization,  Prev: Multi-Phase Initialization,  Up: Module Initialization

9.23.2.2 Single-Phase Initialization
....................................

Extensions that use single-phase initialization (i.e., *note
PyModule_Create(): 50e0.) should call *note PyUnstable_Module_SetGIL():
179. to indicate that they support running with the GIL disabled.  The
function is only defined in the free-threaded build, so you should guard
the call with ‘#ifdef Py_GIL_DISABLED’ to avoid compilation errors in
the regular build.

     static struct PyModuleDef moduledef = {
         PyModuleDef_HEAD_INIT,
         ...
     };

     PyMODINIT_FUNC
     PyInit_mymodule(void)
     {
         PyObject *m = PyModule_Create(&moduledef);
         if (m == NULL) {
             return NULL;
         }
     #ifdef Py_GIL_DISABLED
         PyUnstable_Module_SetGIL(m, Py_MOD_GIL_NOT_USED);
     #endif
         return m;
     }


File: python.info,  Node: General API Guidelines,  Next: Borrowed References,  Prev: Module Initialization,  Up: C API Extension Support for Free Threading

9.23.3 General API Guidelines
-----------------------------

Most of the C API is thread-safe, but there are some exceptions.

   * 'Struct Fields': Accessing fields in Python C API objects or
     structs directly is not thread-safe if the field may be
     concurrently modified.

   * 'Macros': Accessor macros like *note PyList_GET_ITEM: 4c21. and
     *note PyList_SET_ITEM: 391. do not perform any error checking or
     locking.  These macros are not thread-safe if the container object
     may be modified concurrently.

   * 'Borrowed References': C API functions that return *note borrowed
     references: 33f. may not be thread-safe if the containing object is
     modified concurrently.  See the section on *note borrowed
     references: 5506. for more information.

* Menu:

* Container Thread Safety::


File: python.info,  Node: Container Thread Safety,  Up: General API Guidelines

9.23.3.1 Container Thread Safety
................................

Containers like *note PyListObject: 4f58, *note PyDictObject: 3c4, and
*note PySetObject: 506e. perform internal locking in the free-threaded
build.  For example, the *note PyList_Append(): 4d02. will lock the list
before appending an item.

* Menu:

* PyDict_Next::


File: python.info,  Node: PyDict_Next,  Up: Container Thread Safety

9.23.3.2 ‘PyDict_Next’
......................

A notable exception is *note PyDict_Next(): 171b, which does not lock
the dictionary.  You should use *note Py_BEGIN_CRITICAL_SECTION: 5050.
to protect the dictionary while iterating over it if the dictionary may
be concurrently modified:

     Py_BEGIN_CRITICAL_SECTION(dict);
     PyObject *key, *value;
     Py_ssize_t pos = 0;
     while (PyDict_Next(dict, &pos, &key, &value)) {
         ...
     }
     Py_END_CRITICAL_SECTION();


File: python.info,  Node: Borrowed References,  Next: Memory Allocation APIs,  Prev: General API Guidelines,  Up: C API Extension Support for Free Threading

9.23.4 Borrowed References
--------------------------

Some C API functions return *note borrowed references: 33f.  These APIs
are not thread-safe if the containing object is modified concurrently.
For example, it’s not safe to use *note PyList_GetItem(): 35d. if the
list may be modified concurrently.

The following table lists some borrowed reference APIs and their
replacements that return *note strong references: 33e.

Borrowed reference API                  Strong reference API
                                        
--------------------------------------------------------------------------------
                                        
*note PyList_GetItem(): 35d.            *note PyList_GetItemRef(): 35c.
                                        
                                        
*note PyList_GET_ITEM(): 4c21.          *note PyList_GetItemRef(): 35c.
                                        
                                        
*note PyDict_GetItem(): 38a.            *note PyDict_GetItemRef(): 33b.
                                        
                                        
*note PyDict_GetItemWithError(): 33d.   *note PyDict_GetItemRef(): 33b.
                                        
                                        
*note PyDict_GetItemString(): 38b.      *note PyDict_GetItemStringRef(): 33c.
                                        
                                        
*note PyDict_SetDefault(): 341.         *note PyDict_SetDefaultRef(): 340.
                                        
                                        
*note PyDict_Next(): 171b.              none (see *note PyDict_Next: 5509.)
                                        
                                        
*note PyWeakref_GetObject(): 37c.       *note PyWeakref_GetRef(): 37b.
                                        
                                        
*note PyWeakref_GET_OBJECT(): 3c2.      *note PyWeakref_GetRef(): 37b.
                                        
                                        
*note PyImport_AddModule(): 35a.        *note PyImport_AddModuleRef(): 359.
                                        

Not all APIs that return borrowed references are problematic.  For
example, *note PyTuple_GetItem(): 4b82. is safe because tuples are
immutable.  Similarly, not all uses of the above APIs are problematic.
For example, *note PyDict_GetItem(): 38a. is often used for parsing
keyword argument dictionaries in function calls; those keyword argument
dictionaries are effectively private (not accessible by other threads),
so using borrowed references in that context is safe.

Some of these functions were added in Python 3.13.  You can use the
pythoncapi-compat(1) package to provide implementations of these
functions for older Python versions.

   ---------- Footnotes ----------

   (1) https://github.com/python/pythoncapi-compat


File: python.info,  Node: Memory Allocation APIs,  Next: Thread State and GIL APIs,  Prev: Borrowed References,  Up: C API Extension Support for Free Threading

9.23.5 Memory Allocation APIs
-----------------------------

Python’s memory management C API provides functions in three different
*note allocation domains: 523b.: “raw”, “mem”, and “object”.  For
thread-safety, the free-threaded build requires that only Python objects
are allocated using the object domain, and that all Python object are
allocated using that domain.  This differs from the prior Python
versions, where this was only a best practice and not a hard
requirement.

     Note: Search for uses of *note PyObject_Malloc(): c89. in your
     extension and check that the allocated memory is used for Python
     objects.  Use *note PyMem_Malloc(): c87. to allocate buffers
     instead of ‘PyObject_Malloc()’.


File: python.info,  Node: Thread State and GIL APIs,  Next: Protecting Internal Extension State,  Prev: Memory Allocation APIs,  Up: C API Extension Support for Free Threading

9.23.6 Thread State and GIL APIs
--------------------------------

Python provides a set of functions and macros to manage thread state and
the GIL, such as:

   * *note PyGILState_Ensure(): 3ae. and *note PyGILState_Release():
     3af.

   * *note PyEval_SaveThread(): 3ab. and *note PyEval_RestoreThread():
     3ac.

   * *note Py_BEGIN_ALLOW_THREADS: 4b88. and *note Py_END_ALLOW_THREADS:
     a9d.

These functions should still be used in the free-threaded build to
manage thread state even when the *note GIL: 159. is disabled.  For
example, if you create a thread outside of Python, you must call *note
PyGILState_Ensure(): 3ae. before calling into the Python API to ensure
that the thread has a valid Python thread state.

You should continue to call *note PyEval_SaveThread(): 3ab. or *note
Py_BEGIN_ALLOW_THREADS: 4b88. around blocking operations, such as I/O or
lock acquisitions, to allow other threads to run the *note cyclic
garbage collector: 1a83.


File: python.info,  Node: Protecting Internal Extension State,  Next: Building Extensions for the Free-Threaded Build,  Prev: Thread State and GIL APIs,  Up: C API Extension Support for Free Threading

9.23.7 Protecting Internal Extension State
------------------------------------------

Your extension may have internal state that was previously protected by
the GIL. You may need to add locking to protect this state.  The
approach will depend on your extension, but some common patterns
include:

   * 'Caches': global caches are a common source of shared state.
     Consider using a lock to protect the cache or disabling it in the
     free-threaded build if the cache is not critical for performance.

   * 'Global State': global state may need to be protected by a lock or
     moved to thread local storage.  C11 and C++11 provide the
     ‘thread_local’ or ‘_Thread_local’ for thread-local storage(1).

   ---------- Footnotes ----------

   (1) https://en.cppreference.com/w/c/language/storage_duration


File: python.info,  Node: Building Extensions for the Free-Threaded Build,  Prev: Protecting Internal Extension State,  Up: C API Extension Support for Free Threading

9.23.8 Building Extensions for the Free-Threaded Build
------------------------------------------------------

C API extensions need to be built specifically for the free-threaded
build.  The wheels, shared libraries, and binaries are indicated by a
‘t’ suffix.

   * pypa/manylinux(1) supports the free-threaded build, with the ‘t’
     suffix, such as ‘python3.13t’.

   * pypa/cibuildwheel(2) supports the free-threaded build if you set
     CIBW_ENABLE to cpython-freethreading(3).

* Menu:

* Limited C API and Stable ABI::
* Windows: Windows<83>.

   ---------- Footnotes ----------

   (1) https://github.com/pypa/manylinux

   (2) https://github.com/pypa/cibuildwheel

   (3) https://cibuildwheel.pypa.io/en/stable/options/#enable


File: python.info,  Node: Limited C API and Stable ABI,  Next: Windows<83>,  Up: Building Extensions for the Free-Threaded Build

9.23.8.1 Limited C API and Stable ABI
.....................................

The free-threaded build does not currently support the *note Limited C
API: 399. or the stable ABI. If you use setuptools(1) to build your
extension and currently set ‘py_limited_api=True’ you can use
‘py_limited_api=not sysconfig.get_config_var("Py_GIL_DISABLED")’ to opt
out of the limited API when building with the free-threaded build.

     Note: You will need to build separate wheels specifically for the
     free-threaded build.  If you currently use the stable ABI, you can
     continue to build a single wheel for multiple non-free-threaded
     Python versions.

   ---------- Footnotes ----------

   (1) https://setuptools.pypa.io/en/latest/setuptools.html


File: python.info,  Node: Windows<83>,  Prev: Limited C API and Stable ABI,  Up: Building Extensions for the Free-Threaded Build

9.23.8.2 Windows
................

Due to a limitation of the official Windows installer, you will need to
manually define ‘Py_GIL_DISABLED=1’ when building extensions from
source.

See also
........

Porting Extension Modules to Support Free-Threading(1): A
community-maintained porting guide for extension authors.

General:

   * *note A Conceptual Overview of asyncio: 348d.

   * *note Annotations Best Practices: 7dd.

   * *note Argparse Tutorial: 305d.

   * *note Descriptor Guide: 153c.

   * *note Enum HOWTO: 536e.

   * *note Functional Programming HOWTO: 539f.

   * *note An introduction to the ipaddress module: 3e9a.

   * *note Logging HOWTO: 53be.

   * *note Logging Cookbook: 123c.

   * *note Regular expression HOWTO: 24a7.

   * *note Sorting Techniques: 2337.

   * *note Unicode HOWTO: 12ec.

   * *note HOWTO Fetch Internet Resources Using The urllib Package:
     3c5a.

Advanced development:

   * *note Curses Programming with Python: 3155.

   * *note Python experimental support for free threading: 54f1.

   * *note C API Extension Support for Free Threading: 54f4.

   * *note Isolating Extension Modules: 4b6e.

   * *note The Python 2.3 Method Resolution Order: 14f9.

   * *note Socket Programming HOWTO: 3671.

   * *note timer file descriptor HOWTO: 54e4.

   * *note Porting Extension Modules to Python 3: 1329.

Debugging and profiling:

   * *note Debugging C API extensions and CPython Internals with GDB:
     535f.

   * *note Instrumenting CPython with DTrace and SystemTap: c8d.

   * *note Python support for the Linux perf profiler: 18f.

   ---------- Footnotes ----------

   (1) https://py-free-threading.github.io/porting/


File: python.info,  Node: Python Frequently Asked Questions,  Next: Deprecations,  Prev: Python HOWTOs,  Up: Top

10 Python Frequently Asked Questions
************************************

* Menu:

* General Python FAQ::
* Programming FAQ::
* Design and History FAQ::
* Library and Extension FAQ::
* Extending/Embedding FAQ::
* Python on Windows FAQ::
* Graphic User Interface FAQ::
* “Why is Python Installed on my Computer?” FAQ::


File: python.info,  Node: General Python FAQ,  Next: Programming FAQ,  Up: Python Frequently Asked Questions

10.1 General Python FAQ
=======================

* Menu:

* General Information::
* Python in the real world::


File: python.info,  Node: General Information,  Next: Python in the real world,  Up: General Python FAQ

10.1.1 General Information
--------------------------

* Menu:

* What is Python?::
* What is the Python Software Foundation?::
* Are there copyright restrictions on the use of Python?::
* Why was Python created in the first place?::
* What is Python good for?::
* How does the Python version numbering scheme work?::
* How do I obtain a copy of the Python source?::
* How do I get documentation on Python?::
* I’ve never programmed before. Is there a Python tutorial?: I’ve never programmed before Is there a Python tutorial?.
* Is there a newsgroup or mailing list devoted to Python?::
* How do I get a beta test version of Python?::
* How do I submit bug reports and patches for Python?::
* Are there any published articles about Python that I can reference?::
* Are there any books on Python?::
* Where in the world is www.python.org located?: Where in the world is www python org located?.
* Why is it called Python?::
* Do I have to like “Monty Python’s Flying Circus”?::


File: python.info,  Node: What is Python?,  Next: What is the Python Software Foundation?,  Up: General Information

10.1.1.1 What is Python?
........................

Python is an interpreted, interactive, object-oriented programming
language.  It incorporates modules, exceptions, dynamic typing, very
high level dynamic data types, and classes.  It supports multiple
programming paradigms beyond object-oriented programming, such as
procedural and functional programming.  Python combines remarkable power
with very clear syntax.  It has interfaces to many system calls and
libraries, as well as to various window systems, and is extensible in C
or C++.  It is also usable as an extension language for applications
that need a programmable interface.  Finally, Python is portable: it
runs on many Unix variants including Linux and macOS, and on Windows.

To find out more, start with *note The Python Tutorial: 1d6d.  The
Beginner's Guide to Python(1) links to other introductory tutorials and
resources for learning Python.

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/BeginnersGuide


File: python.info,  Node: What is the Python Software Foundation?,  Next: Are there copyright restrictions on the use of Python?,  Prev: What is Python?,  Up: General Information

10.1.1.2 What is the Python Software Foundation?
................................................

The Python Software Foundation is an independent non-profit organization
that holds the copyright on Python versions 2.1 and newer.  The PSF’s
mission is to advance open source technology related to the Python
programming language and to publicize the use of Python.  The PSF’s home
page is at ‘https://www.python.org/psf/’.

Donations to the PSF are tax-exempt in the US. If you use Python and
find it helpful, please contribute via the PSF donation page(1).

   ---------- Footnotes ----------

   (1) https://www.python.org/psf/donations/


File: python.info,  Node: Are there copyright restrictions on the use of Python?,  Next: Why was Python created in the first place?,  Prev: What is the Python Software Foundation?,  Up: General Information

10.1.1.3 Are there copyright restrictions on the use of Python?
...............................................................

You can do anything you want with the source, as long as you leave the
copyrights in and display those copyrights in any documentation about
Python that you produce.  If you honor the copyright rules, it’s OK to
use Python for commercial use, to sell copies of Python in source or
binary form (modified or unmodified), or to sell products that
incorporate Python in some form.  We would still like to know about all
commercial use of Python, of course.

See the license page(1) to find further explanations and the full text
of the PSF License.

The Python logo is trademarked, and in certain cases permission is
required to use it.  Consult the Trademark Usage Policy(2) for more
information.

   ---------- Footnotes ----------

   (1) https://docs.python.org/3/license.html

   (2) https://www.python.org/psf/trademarks/


File: python.info,  Node: Why was Python created in the first place?,  Next: What is Python good for?,  Prev: Are there copyright restrictions on the use of Python?,  Up: General Information

10.1.1.4 Why was Python created in the first place?
...................................................

Here’s a 'very' brief summary of what started it all, written by Guido
van Rossum:

     I had extensive experience with implementing an interpreted
     language in the ABC group at CWI, and from working with this group
     I had learned a lot about language design.  This is the origin of
     many Python features, including the use of indentation for
     statement grouping and the inclusion of very-high-level data types
     (although the details are all different in Python).

     I had a number of gripes about the ABC language, but also liked
     many of its features.  It was impossible to extend the ABC language
     (or its implementation) to remedy my complaints – in fact its lack
     of extensibility was one of its biggest problems.  I had some
     experience with using Modula-2+ and talked with the designers of
     Modula-3 and read the Modula-3 report.  Modula-3 is the origin of
     the syntax and semantics used for exceptions, and some other Python
     features.

     I was working in the Amoeba distributed operating system group at
     CWI. We needed a better way to do system administration than by
     writing either C programs or Bourne shell scripts, since Amoeba had
     its own system call interface which wasn’t easily accessible from
     the Bourne shell.  My experience with error handling in Amoeba made
     me acutely aware of the importance of exceptions as a programming
     language feature.

     It occurred to me that a scripting language with a syntax like ABC
     but with access to the Amoeba system calls would fill the need.  I
     realized that it would be foolish to write an Amoeba-specific
     language, so I decided that I needed a language that was generally
     extensible.

     During the 1989 Christmas holidays, I had a lot of time on my hand,
     so I decided to give it a try.  During the next year, while still
     mostly working on it in my own time, Python was used in the Amoeba
     project with increasing success, and the feedback from colleagues
     made me add many early improvements.

     In February 1991, after just over a year of development, I decided
     to post to USENET. The rest is in the ‘Misc/HISTORY’ file.


File: python.info,  Node: What is Python good for?,  Next: How does the Python version numbering scheme work?,  Prev: Why was Python created in the first place?,  Up: General Information

10.1.1.5 What is Python good for?
.................................

Python is a high-level general-purpose programming language that can be
applied to many different classes of problems.

The language comes with a large standard library that covers areas such
as string processing (regular expressions, Unicode, calculating
differences between files), internet protocols (HTTP, FTP, SMTP,
XML-RPC, POP, IMAP), software engineering (unit testing, logging,
profiling, parsing Python code), and operating system interfaces (system
calls, filesystems, TCP/IP sockets).  Look at the table of contents for
*note The Python Standard Library: 144. to get an idea of what’s
available.  A wide variety of third-party extensions are also available.
Consult the Python Package Index(1) to find packages of interest to you.

   ---------- Footnotes ----------

   (1) https://pypi.org


File: python.info,  Node: How does the Python version numbering scheme work?,  Next: How do I obtain a copy of the Python source?,  Prev: What is Python good for?,  Up: General Information

10.1.1.6 How does the Python version numbering scheme work?
...........................................................

Python versions are numbered “A.B.C” or “A.B”:

   * 'A' is the major version number – it is only incremented for really
     major changes in the language.

   * 'B' is the minor version number – it is incremented for less
     earth-shattering changes.

   * 'C' is the micro version number – it is incremented for each bugfix
     release.

Not all releases are bugfix releases.  In the run-up to a new feature
release, a series of development releases are made, denoted as alpha,
beta, or release candidate.  Alphas are early releases in which
interfaces aren’t yet finalized; it’s not unexpected to see an interface
change between two alpha releases.  Betas are more stable, preserving
existing interfaces but possibly adding new modules, and release
candidates are frozen, making no changes except as needed to fix
critical bugs.

Alpha, beta and release candidate versions have an additional suffix:

   * The suffix for an alpha version is “aN” for some small number 'N'.

   * The suffix for a beta version is “bN” for some small number 'N'.

   * The suffix for a release candidate version is “rcN” for some small
     number 'N'.

In other words, all versions labeled '2.0aN' precede the versions
labeled '2.0bN', which precede versions labeled '2.0rcN', and 'those'
precede 2.0.

You may also find version numbers with a “+” suffix, e.g.  “2.2+”.
These are unreleased versions, built directly from the CPython
development repository.  In practice, after a final minor release is
made, the version is incremented to the next minor version, which
becomes the “a0” version, e.g.  “2.4a0”.

See the Developer's Guide(1) for more information about the development
cycle, and PEP 387(2) to learn more about Python’s backward
compatibility policy.  See also the documentation for *note sys.version:
178, *note sys.hexversion: 45e7, and *note sys.version_info: 6a3.

   ---------- Footnotes ----------

   (1) https://devguide.python.org/developer-workflow/development-cycle/

   (2) https://peps.python.org/pep-0387/


File: python.info,  Node: How do I obtain a copy of the Python source?,  Next: How do I get documentation on Python?,  Prev: How does the Python version numbering scheme work?,  Up: General Information

10.1.1.7 How do I obtain a copy of the Python source?
.....................................................

The latest Python source distribution is always available from
python.org, at ‘https://www.python.org/downloads/’.  The latest
development sources can be obtained at
‘https://github.com/python/cpython/’.

The source distribution is a gzipped tar file containing the complete C
source, Sphinx-formatted documentation, Python library modules, example
programs, and several useful pieces of freely distributable software.
The source will compile and run out of the box on most UNIX platforms.

Consult the Getting Started section of the Python Developer's Guide(1)
for more information on getting the source code and compiling it.

   ---------- Footnotes ----------

   (1) https://devguide.python.org/setup/


File: python.info,  Node: How do I get documentation on Python?,  Next: I’ve never programmed before Is there a Python tutorial?,  Prev: How do I obtain a copy of the Python source?,  Up: General Information

10.1.1.8 How do I get documentation on Python?
..............................................

The standard documentation for the current stable version of Python is
available at ‘https://docs.python.org/3/’.  EPUB, plain text, and
downloadable HTML versions are also available at
‘https://docs.python.org/3/download.html’.

The documentation is written in reStructuredText and processed by the
Sphinx documentation tool(1).  The reStructuredText source for the
documentation is part of the Python source distribution.

   ---------- Footnotes ----------

   (1) https://www.sphinx-doc.org/


File: python.info,  Node: I’ve never programmed before Is there a Python tutorial?,  Next: Is there a newsgroup or mailing list devoted to Python?,  Prev: How do I get documentation on Python?,  Up: General Information

10.1.1.9 I’ve never programmed before. Is there a Python tutorial?
..................................................................

There are numerous tutorials and books available.  The standard
documentation includes *note The Python Tutorial: 1d6d.

Consult the Beginner's Guide(1) to find information for beginning Python
programmers, including lists of tutorials.

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/BeginnersGuide


File: python.info,  Node: Is there a newsgroup or mailing list devoted to Python?,  Next: How do I get a beta test version of Python?,  Prev: I’ve never programmed before Is there a Python tutorial?,  Up: General Information

10.1.1.10 Is there a newsgroup or mailing list devoted to Python?
.................................................................

There is a newsgroup, ‘comp.lang.python’, and a mailing list,
python-list(1).  The newsgroup and mailing list are gatewayed into each
other – if you can read news it’s unnecessary to subscribe to the
mailing list.  ‘comp.lang.python’ is high-traffic, receiving hundreds of
postings every day, and Usenet readers are often more able to cope with
this volume.

Announcements of new software releases and events can be found in
comp.lang.python.announce, a low-traffic moderated list that receives
about five postings per day.  It’s available as the python-announce
mailing list(2).

More info about other mailing lists and newsgroups can be found at
‘https://www.python.org/community/lists/’.

   ---------- Footnotes ----------

   (1) https://mail.python.org/mailman/listinfo/python-list

   (2) 
https://mail.python.org/mailman3/lists/python-announce-list.python.org/


File: python.info,  Node: How do I get a beta test version of Python?,  Next: How do I submit bug reports and patches for Python?,  Prev: Is there a newsgroup or mailing list devoted to Python?,  Up: General Information

10.1.1.11 How do I get a beta test version of Python?
.....................................................

Alpha and beta releases are available from
‘https://www.python.org/downloads/’.  All releases are announced on the
comp.lang.python and comp.lang.python.announce newsgroups and on the
Python home page at ‘https://www.python.org/’; an RSS feed of news is
available.

You can also access the development version of Python through Git.  See
The Python Developer's Guide(1) for details.

   ---------- Footnotes ----------

   (1) https://devguide.python.org/


File: python.info,  Node: How do I submit bug reports and patches for Python?,  Next: Are there any published articles about Python that I can reference?,  Prev: How do I get a beta test version of Python?,  Up: General Information

10.1.1.12 How do I submit bug reports and patches for Python?
.............................................................

To report a bug or submit a patch, use the issue tracker at
‘https://github.com/python/cpython/issues’.

For more information on how Python is developed, consult the Python
Developer's Guide(1).

   ---------- Footnotes ----------

   (1) https://devguide.python.org/


File: python.info,  Node: Are there any published articles about Python that I can reference?,  Next: Are there any books on Python?,  Prev: How do I submit bug reports and patches for Python?,  Up: General Information

10.1.1.13 Are there any published articles about Python that I can reference?
.............................................................................

It’s probably best to cite your favorite book about Python.

The very first article(1) about Python was written in 1991 and is now
quite outdated.

     Guido van Rossum and Jelke de Boer, “Interactively Testing Remote
     Servers Using the Python Programming Language”, CWI Quarterly,
     Volume 4, Issue 4 (December 1991), Amsterdam, pp 283–303.

   ---------- Footnotes ----------

   (1) https://ir.cwi.nl/pub/18204


File: python.info,  Node: Are there any books on Python?,  Next: Where in the world is www python org located?,  Prev: Are there any published articles about Python that I can reference?,  Up: General Information

10.1.1.14 Are there any books on Python?
........................................

Yes, there are many, and more are being published.  See the python.org
wiki at ‘https://wiki.python.org/moin/PythonBooks’ for a list.

You can also search online bookstores for “Python” and filter out the
Monty Python references; or perhaps search for “Python” and “language”.


File: python.info,  Node: Where in the world is www python org located?,  Next: Why is it called Python?,  Prev: Are there any books on Python?,  Up: General Information

10.1.1.15 Where in the world is www.python.org located?
.......................................................

The Python project’s infrastructure is located all over the world and is
managed by the Python Infrastructure Team.  Details here(1).

   ---------- Footnotes ----------

   (1) https://infra.psf.io


File: python.info,  Node: Why is it called Python?,  Next: Do I have to like “Monty Python’s Flying Circus”?,  Prev: Where in the world is www python org located?,  Up: General Information

10.1.1.16 Why is it called Python?
..................................

When he began implementing Python, Guido van Rossum was also reading the
published scripts from "Monty Python's Flying Circus"(1), a BBC comedy
series from the 1970s.  Van Rossum thought he needed a name that was
short, unique, and slightly mysterious, so he decided to call the
language Python.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/Monty_Python


File: python.info,  Node: Do I have to like “Monty Python’s Flying Circus”?,  Prev: Why is it called Python?,  Up: General Information

10.1.1.17 Do I have to like “Monty Python’s Flying Circus”?
...........................................................

No, but it helps.  :)


File: python.info,  Node: Python in the real world,  Prev: General Information,  Up: General Python FAQ

10.1.2 Python in the real world
-------------------------------

* Menu:

* How stable is Python?::
* How many people are using Python?::
* Have any significant projects been done in Python?::
* What new developments are expected for Python in the future?::
* Is it reasonable to propose incompatible changes to Python?::
* Is Python a good language for beginning programmers?::


File: python.info,  Node: How stable is Python?,  Next: How many people are using Python?,  Up: Python in the real world

10.1.2.1 How stable is Python?
..............................

Very stable.  New, stable releases have been coming out roughly every 6
to 18 months since 1991, and this seems likely to continue.  As of
version 3.9, Python will have a new feature release every 12 months (
PEP 602(1)).

The developers issue bugfix releases of older versions, so the stability
of existing releases gradually improves.  Bugfix releases, indicated by
a third component of the version number (e.g.  3.5.3, 3.6.2), are
managed for stability; only fixes for known problems are included in a
bugfix release, and it’s guaranteed that interfaces will remain the same
throughout a series of bugfix releases.

The latest stable releases can always be found on the Python download
page(2).  Python 3.x is the recommended version and supported by most
widely used libraries.  Python 2.x is not maintained anymore(3).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0602/

   (2) https://www.python.org/downloads/

   (3) https://peps.python.org/pep-0373/


File: python.info,  Node: How many people are using Python?,  Next: Have any significant projects been done in Python?,  Prev: How stable is Python?,  Up: Python in the real world

10.1.2.2 How many people are using Python?
..........................................

There are probably millions of users, though it’s difficult to obtain an
exact count.

Python is available for free download, so there are no sales figures,
and it’s available from many different sites and packaged with many
Linux distributions, so download statistics don’t tell the whole story
either.

The comp.lang.python newsgroup is very active, but not all Python users
post to the group or even read it.


File: python.info,  Node: Have any significant projects been done in Python?,  Next: What new developments are expected for Python in the future?,  Prev: How many people are using Python?,  Up: Python in the real world

10.1.2.3 Have any significant projects been done in Python?
...........................................................

See ‘https://www.python.org/about/success’ for a list of projects that
use Python.  Consulting the proceedings for past Python conferences(1)
will reveal contributions from many different companies and
organizations.

High-profile Python projects include the Mailman mailing list manager(2)
and the Zope application server(3).  Several Linux distributions, most
notably Red Hat(4), have written part or all of their installer and
system administration software in Python.  Companies that use Python
internally include Google, Yahoo, and Lucasfilm Ltd.

   ---------- Footnotes ----------

   (1) https://www.python.org/community/workshops/

   (2) https://www.list.org

   (3) https://www.zope.dev

   (4) https://www.redhat.com


File: python.info,  Node: What new developments are expected for Python in the future?,  Next: Is it reasonable to propose incompatible changes to Python?,  Prev: Have any significant projects been done in Python?,  Up: Python in the real world

10.1.2.4 What new developments are expected for Python in the future?
.....................................................................

See ‘https://peps.python.org/’ for the Python Enhancement Proposals
(PEPs).  PEPs are design documents describing a suggested new feature
for Python, providing a concise technical specification and a rationale.
Look for a PEP titled “Python X.Y Release Schedule”, where X.Y is a
version that hasn’t been publicly released yet.

New development is discussed on the python-dev mailing list(1).

   ---------- Footnotes ----------

   (1) https://mail.python.org/mailman3/lists/python-dev.python.org/


File: python.info,  Node: Is it reasonable to propose incompatible changes to Python?,  Next: Is Python a good language for beginning programmers?,  Prev: What new developments are expected for Python in the future?,  Up: Python in the real world

10.1.2.5 Is it reasonable to propose incompatible changes to Python?
....................................................................

In general, no.  There are already millions of lines of Python code
around the world, so any change in the language that invalidates more
than a very small fraction of existing programs has to be frowned upon.
Even if you can provide a conversion program, there’s still the problem
of updating all documentation; many books have been written about
Python, and we don’t want to invalidate them all at a single stroke.

Providing a gradual upgrade path is necessary if a feature has to be
changed.  PEP 5(1) describes the procedure followed for introducing
backward-incompatible changes while minimizing disruption for users.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0005/


File: python.info,  Node: Is Python a good language for beginning programmers?,  Prev: Is it reasonable to propose incompatible changes to Python?,  Up: Python in the real world

10.1.2.6 Is Python a good language for beginning programmers?
.............................................................

Yes.

It is still common to start students with a procedural and statically
typed language such as Pascal, C, or a subset of C++ or Java.  Students
may be better served by learning Python as their first language.  Python
has a very simple and consistent syntax and a large standard library
and, most importantly, using Python in a beginning programming course
lets students concentrate on important programming skills such as
problem decomposition and data type design.  With Python, students can
be quickly introduced to basic concepts such as loops and procedures.
They can probably even work with user-defined objects in their very
first course.

For a student who has never programmed before, using a statically typed
language seems unnatural.  It presents additional complexity that the
student must master and slows the pace of the course.  The students are
trying to learn to think like a computer, decompose problems, design
consistent interfaces, and encapsulate data.  While learning to use a
statically typed language is important in the long term, it is not
necessarily the best topic to address in the students’ first programming
course.

Many other aspects of Python make it a good first language.  Like Java,
Python has a large standard library so that students can be assigned
programming projects very early in the course that 'do' something.
Assignments aren’t restricted to the standard four-function calculator
and check balancing programs.  By using the standard library, students
can gain the satisfaction of working on realistic applications as they
learn the fundamentals of programming.  Using the standard library also
teaches students about code reuse.  Third-party modules such as PyGame
are also helpful in extending the students’ reach.

Python’s interactive interpreter enables students to test language
features while they’re programming.  They can keep a window with the
interpreter running while they enter their program’s source in another
window.  If they can’t remember the methods for a list, they can do
something like this:

     >>> L = []
     >>> dir(L)
     ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
     '__dir__', '__doc__', '__eq__', '__format__', '__ge__',
     '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__',
     '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__',
     '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__',
     '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__',
     '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear',
     'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove',
     'reverse', 'sort']
     >>> [d for d in dir(L) if '__' not in d]
     ['append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

     >>> help(L.append)
     Help on built-in function append:

     append(...)
         L.append(object) -> None -- append object to end

     >>> L.append(1)
     >>> L
     [1]

With the interpreter, documentation is never far from the student as
they are programming.

There are also good IDEs for Python.  IDLE is a cross-platform IDE for
Python that is written in Python using Tkinter.  Emacs users will be
happy to know that there is a very good Python mode for Emacs.  All of
these programming environments provide syntax highlighting,
auto-indenting, and access to the interactive interpreter while coding.
Consult the Python wiki(1) for a full list of Python editing
environments.

If you want to discuss Python’s use in education, you may be interested
in joining the edu-sig mailing list(2).

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/PythonEditors

   (2) https://www.python.org/community/sigs/current/edu-sig


File: python.info,  Node: Programming FAQ,  Next: Design and History FAQ,  Prev: General Python FAQ,  Up: Python Frequently Asked Questions

10.2 Programming FAQ
====================

* Menu:

* General questions::
* Core language::
* Numbers and strings::
* Performance: Performance<4>.
* Sequences (tuples/lists): Sequences tuples/lists.
* Objects::
* Modules: Modules<5>.


File: python.info,  Node: General questions,  Next: Core language,  Up: Programming FAQ

10.2.1 General questions
------------------------

* Menu:

* Is there a source code-level debugger with breakpoints and single-stepping?::
* Are there tools to help find bugs or perform static analysis?::
* How can I create a stand-alone binary from a Python script?::
* Are there coding standards or a style guide for Python programs?::


File: python.info,  Node: Is there a source code-level debugger with breakpoints and single-stepping?,  Next: Are there tools to help find bugs or perform static analysis?,  Up: General questions

10.2.1.1 Is there a source code-level debugger with breakpoints and single-stepping?
....................................................................................

Yes.

Several debuggers for Python are described below, and the built-in
function *note breakpoint(): 234. allows you to drop into any of them.

The pdb module is a simple but adequate console-mode debugger for
Python.  It is part of the standard Python library, and is *note
documented in the Library Reference Manual: a5.  You can also write your
own debugger by using the code for pdb as an example.

The IDLE interactive development environment, which is part of the
standard Python distribution (normally available as *note idlelib: 73.),
includes a graphical debugger.

PythonWin is a Python IDE that includes a GUI debugger based on pdb.
The PythonWin debugger colors breakpoints and has quite a few cool
features such as debugging non-PythonWin programs.  PythonWin is
available as part of pywin32(1) project and as a part of the
ActivePython(2) distribution.

Eric(3) is an IDE built on PyQt and the Scintilla editing component.

trepan3k(4) is a gdb-like debugger.

Visual Studio Code(5) is an IDE with debugging tools that integrates
with version-control software.

There are a number of commercial Python IDEs that include graphical
debuggers.  They include:

   * Wing IDE(6)

   * PyCharm(7)

   ---------- Footnotes ----------

   (1) https://github.com/mhammond/pywin32

   (2) https://www.activestate.com/products/python/

   (3) https://eric-ide.python-projects.org/

   (4) https://github.com/rocky/python3-trepan/

   (5) https://code.visualstudio.com/

   (6) https://wingware.com/

   (7) https://www.jetbrains.com/pycharm/


File: python.info,  Node: Are there tools to help find bugs or perform static analysis?,  Next: How can I create a stand-alone binary from a Python script?,  Prev: Is there a source code-level debugger with breakpoints and single-stepping?,  Up: General questions

10.2.1.2 Are there tools to help find bugs or perform static analysis?
......................................................................

Yes.

Ruff(1), Pylint(2) and Pyflakes(3) do basic checking that will help you
catch bugs sooner.

Static type checkers such as mypy(4), ty(5), Pyrefly(6), and pytype(7)
can check type hints in Python source code.

   ---------- Footnotes ----------

   (1) https://docs.astral.sh/ruff/

   (2) https://pylint.readthedocs.io/

   (3) https://github.com/PyCQA/pyflakes

   (4) https://mypy-lang.org/

   (5) https://docs.astral.sh/ty/

   (6) https://pyrefly.org/

   (7) https://github.com/google/pytype


File: python.info,  Node: How can I create a stand-alone binary from a Python script?,  Next: Are there coding standards or a style guide for Python programs?,  Prev: Are there tools to help find bugs or perform static analysis?,  Up: General questions

10.2.1.3 How can I create a stand-alone binary from a Python script?
....................................................................

You don’t need the ability to compile Python to C code if all you want
is a stand-alone program that users can download and run without having
to install the Python distribution first.  There are a number of tools
that determine the set of modules required by a program and bind these
modules together with a Python binary to produce a single executable.

One is to use the freeze tool, which is included in the Python source
tree as Tools/freeze(1).  It converts Python byte code to C arrays; with
a C compiler you can embed all your modules into a new program, which is
then linked with the standard Python modules.

It works by scanning your source recursively for import statements (in
both forms) and looking for the modules in the standard Python path as
well as in the source directory (for built-in modules).  It then turns
the bytecode for modules written in Python into C code (array
initializers that can be turned into code objects using the marshal
module) and creates a custom-made config file that only contains those
built-in modules which are actually used in the program.  It then
compiles the generated C code and links it with the rest of the Python
interpreter to form a self-contained binary which acts exactly like your
script.

The following packages can help with the creation of console and GUI
executables:

   * Nuitka(2) (Cross-platform)

   * PyInstaller(3) (Cross-platform)

   * PyOxidizer(4) (Cross-platform)

   * cx_Freeze(5) (Cross-platform)

   * py2app(6) (macOS only)

   * py2exe(7) (Windows only)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Tools/freeze

   (2) https://nuitka.net/

   (3) https://pyinstaller.org/

   (4) https://pyoxidizer.readthedocs.io/en/stable/

   (5) https://marcelotduarte.github.io/cx_Freeze/

   (6) https://github.com/ronaldoussoren/py2app

   (7) https://www.py2exe.org/


File: python.info,  Node: Are there coding standards or a style guide for Python programs?,  Prev: How can I create a stand-alone binary from a Python script?,  Up: General questions

10.2.1.4 Are there coding standards or a style guide for Python programs?
.........................................................................

Yes.  The coding style required for standard library modules is
documented as PEP 8(1).

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: Core language,  Next: Numbers and strings,  Prev: General questions,  Up: Programming FAQ

10.2.2 Core language
--------------------

* Menu:

* Why am I getting an UnboundLocalError when the variable has a value?::
* What are the rules for local and global variables in Python?::
* Why do lambdas defined in a loop with different values all return the same result?::
* How do I share global variables across modules?::
* What are the “best practices” for using import in a module?::
* Why are default values shared between objects?::
* How can I pass optional or keyword parameters from one function to another?::
* What is the difference between arguments and parameters?::
* Why did changing list ‘y’ also change list ‘x’?::
* How do I write a function with output parameters (call by reference)?: How do I write a function with output parameters call by reference ?.
* How do you make a higher order function in Python?::
* How do I copy an object in Python?::
* How can I find the methods or attributes of an object?::
* How can my code discover the name of an object?::
* What’s up with the comma operator’s precedence?::
* Is there an equivalent of C’s “?;” ternary operator?: Is there an equivalent of C’s “? ” ternary operator?.
* Is it possible to write obfuscated one-liners in Python?::
* What does the slash(/) in the parameter list of a function mean?: What does the slash / in the parameter list of a function mean?.


File: python.info,  Node: Why am I getting an UnboundLocalError when the variable has a value?,  Next: What are the rules for local and global variables in Python?,  Up: Core language

10.2.2.1 Why am I getting an UnboundLocalError when the variable has a value?
.............................................................................

It can be a surprise to get the *note UnboundLocalError: 1586. in
previously working code when it is modified by adding an assignment
statement somewhere in the body of a function.

This code:

     >>> x = 10
     >>> def bar():
     ...     print(x)
     ...
     >>> bar()
     10

works, but this code:

     >>> x = 10
     >>> def foo():
     ...     print(x)
     ...     x += 1

results in an ‘UnboundLocalError’:

     >>> foo()
     Traceback (most recent call last):
       ...
     UnboundLocalError: cannot access local variable 'x' where it is not associated with a value

This is because when you make an assignment to a variable in a scope,
that variable becomes local to that scope and shadows any similarly
named variable in the outer scope.  Since the last statement in foo
assigns a new value to ‘x’, the compiler recognizes it as a local
variable.  Consequently when the earlier ‘print(x)’ attempts to print
the uninitialized local variable and an error results.

In the example above you can access the outer scope variable by
declaring it global:

     >>> x = 10
     >>> def foobar():
     ...     global x
     ...     print(x)
     ...     x += 1
     ...
     >>> foobar()
     10

This explicit declaration is required in order to remind you that
(unlike the superficially analogous situation with class and instance
variables) you are actually modifying the value of the variable in the
outer scope:

     >>> print(x)
     11

You can do a similar thing in a nested scope using the *note nonlocal:
12ef. keyword:

     >>> def foo():
     ...    x = 10
     ...    def bar():
     ...        nonlocal x
     ...        print(x)
     ...        x += 1
     ...    bar()
     ...    print(x)
     ...
     >>> foo()
     10
     11


File: python.info,  Node: What are the rules for local and global variables in Python?,  Next: Why do lambdas defined in a loop with different values all return the same result?,  Prev: Why am I getting an UnboundLocalError when the variable has a value?,  Up: Core language

10.2.2.2 What are the rules for local and global variables in Python?
.....................................................................

In Python, variables that are only referenced inside a function are
implicitly global.  If a variable is assigned a value anywhere within
the function’s body, it’s assumed to be a local unless explicitly
declared as global.

Though a bit surprising at first, a moment’s consideration explains
this.  On one hand, requiring *note global: 18a. for assigned variables
provides a bar against unintended side-effects.  On the other hand, if
‘global’ was required for all global references, you’d be using ‘global’
all the time.  You’d have to declare as global every reference to a
built-in function or to a component of an imported module.  This clutter
would defeat the usefulness of the ‘global’ declaration for identifying
side-effects.


File: python.info,  Node: Why do lambdas defined in a loop with different values all return the same result?,  Next: How do I share global variables across modules?,  Prev: What are the rules for local and global variables in Python?,  Up: Core language

10.2.2.3 Why do lambdas defined in a loop with different values all return the same result?
...........................................................................................

Assume you use a for loop to define a few different lambdas (or even
plain functions), for example:

     >>> squares = []
     >>> for x in range(5):
     ...     squares.append(lambda: x**2)

This gives you a list that contains 5 lambdas that calculate ‘x**2’.
You might expect that, when called, they would return, respectively,
‘0’, ‘1’, ‘4’, ‘9’, and ‘16’.  However, when you actually try you will
see that they all return ‘16’:

     >>> squares[2]()
     16
     >>> squares[4]()
     16

This happens because ‘x’ is not local to the lambdas, but is defined in
the outer scope, and it is accessed when the lambda is called — not when
it is defined.  At the end of the loop, the value of ‘x’ is ‘4’, so all
the functions now return ‘4**2’, that is ‘16’.  You can also verify this
by changing the value of ‘x’ and see how the results of the lambdas
change:

     >>> x = 8
     >>> squares[2]()
     64

In order to avoid this, you need to save the values in variables local
to the lambdas, so that they don’t rely on the value of the global ‘x’:

     >>> squares = []
     >>> for x in range(5):
     ...     squares.append(lambda n=x: n**2)

Here, ‘n=x’ creates a new variable ‘n’ local to the lambda and computed
when the lambda is defined so that it has the same value that ‘x’ had at
that point in the loop.  This means that the value of ‘n’ will be ‘0’ in
the first lambda, ‘1’ in the second, ‘2’ in the third, and so on.
Therefore each lambda will now return the correct result:

     >>> squares[2]()
     4
     >>> squares[4]()
     16

Note that this behaviour is not peculiar to lambdas, but applies to
regular functions too.


File: python.info,  Node: How do I share global variables across modules?,  Next: What are the “best practices” for using import in a module?,  Prev: Why do lambdas defined in a loop with different values all return the same result?,  Up: Core language

10.2.2.4 How do I share global variables across modules?
........................................................

The canonical way to share information across modules within a single
program is to create a special module (often called config or cfg).
Just import the config module in all modules of your application; the
module then becomes available as a global name.  Because there is only
one instance of each module, any changes made to the module object get
reflected everywhere.  For example:

config.py:

     x = 0   # Default value of the 'x' configuration setting

mod.py:

     import config
     config.x = 1

main.py:

     import config
     import mod
     print(config.x)

Note that using a module is also the basis for implementing the
singleton design pattern, for the same reason.


File: python.info,  Node: What are the “best practices” for using import in a module?,  Next: Why are default values shared between objects?,  Prev: How do I share global variables across modules?,  Up: Core language

10.2.2.5 What are the “best practices” for using import in a module?
....................................................................

In general, don’t use ‘from modulename import *’.  Doing so clutters the
importer’s namespace, and makes it much harder for linters to detect
undefined names.

Import modules at the top of a file.  Doing so makes it clear what other
modules your code requires and avoids questions of whether the module
name is in scope.  Using one import per line makes it easy to add and
delete module imports, but using multiple imports per line uses less
screen space.

It’s good practice if you import modules in the following order:

  1. standard library modules – such as *note sys: d9, *note os: a1,
     *note argparse: 6, *note re: b9.

  2. third-party library modules (anything installed in Python’s
     site-packages directory) – such as dateutil(1), requests(2),
     tzdata(3)

  3. locally developed modules

It is sometimes necessary to move imports to a function or class to
avoid problems with circular imports.  Gordon McMillan says:

     Circular imports are fine where both modules use the “import
     <module>” form of import.  They fail when the 2nd module wants to
     grab a name out of the first (“from module import name”) and the
     import is at the top level.  That’s because names in the 1st are
     not yet available, because the first module is busy importing the
     2nd.

In this case, if the second module is only used in one function, then
the import can easily be moved into that function.  By the time the
import is called, the first module will have finished initializing, and
the second module can do its import.

It may also be necessary to move imports out of the top level of code if
some of the modules are platform-specific.  In that case, it may not
even be possible to import all of the modules at the top of the file.
In this case, importing the correct modules in the corresponding
platform-specific code is a good option.

Only move imports into a local scope, such as inside a function
definition, if it’s necessary to solve a problem such as avoiding a
circular import or are trying to reduce the initialization time of a
module.  This technique is especially helpful if many of the imports are
unnecessary depending on how the program executes.  You may also want to
move imports into a function if the modules are only ever used in that
function.  Note that loading a module the first time may be expensive
because of the one time initialization of the module, but loading a
module multiple times is virtually free, costing only a couple of
dictionary lookups.  Even if the module name has gone out of scope, the
module is probably available in *note sys.modules: 1655.

   ---------- Footnotes ----------

   (1) https://pypi.org/project/dateutil/

   (2) https://pypi.org/project/requests/

   (3) https://pypi.org/project/tzdata/


File: python.info,  Node: Why are default values shared between objects?,  Next: How can I pass optional or keyword parameters from one function to another?,  Prev: What are the “best practices” for using import in a module?,  Up: Core language

10.2.2.6 Why are default values shared between objects?
.......................................................

This type of bug commonly bites neophyte programmers.  Consider this
function:

     def foo(mydict={}):  # Danger: shared reference to one dict for all calls
         ... compute something ...
         mydict[key] = value
         return mydict

The first time you call this function, ‘mydict’ contains a single item.
The second time, ‘mydict’ contains two items because when ‘foo()’ begins
executing, ‘mydict’ starts out with an item already in it.

It is often expected that a function call creates new objects for
default values.  This is not what happens.  Default values are created
exactly once, when the function is defined.  If that object is changed,
like the dictionary in this example, subsequent calls to the function
will refer to this changed object.

By definition, immutable objects such as numbers, strings, tuples, and
‘None’, are safe from change.  Changes to mutable objects such as
dictionaries, lists, and class instances can lead to confusion.

Because of this feature, it is good programming practice to not use
mutable objects as default values.  Instead, use ‘None’ as the default
value and inside the function, check if the parameter is ‘None’ and
create a new list/dictionary/whatever if it is.  For example, don’t
write:

     def foo(mydict={}):
         ...

but:

     def foo(mydict=None):
         if mydict is None:
             mydict = {}  # create a new dict for local namespace

This feature can be useful.  When you have a function that’s
time-consuming to compute, a common technique is to cache the parameters
and the resulting value of each call to the function, and return the
cached value if the same value is requested again.  This is called
“memoizing”, and can be implemented like this:

     # Callers can only provide two parameters and optionally pass _cache by keyword
     def expensive(arg1, arg2, *, _cache={}):
         if (arg1, arg2) in _cache:
             return _cache[(arg1, arg2)]

         # Calculate the value
         result = ... expensive computation ...
         _cache[(arg1, arg2)] = result           # Store result in the cache
         return result

You could use a global variable containing a dictionary instead of the
default value; it’s a matter of taste.


File: python.info,  Node: How can I pass optional or keyword parameters from one function to another?,  Next: What is the difference between arguments and parameters?,  Prev: Why are default values shared between objects?,  Up: Core language

10.2.2.7 How can I pass optional or keyword parameters from one function to another?
....................................................................................

Collect the arguments using the ‘*’ and ‘**’ specifiers in the
function’s parameter list; this gives you the positional arguments as a
tuple and the keyword arguments as a dictionary.  You can then pass
these arguments when calling another function by using ‘*’ and ‘**’:

     def f(x, *args, **kwargs):
         ...
         kwargs['width'] = '14.3c'
         ...
         g(x, *args, **kwargs)


File: python.info,  Node: What is the difference between arguments and parameters?,  Next: Why did changing list ‘y’ also change list ‘x’?,  Prev: How can I pass optional or keyword parameters from one function to another?,  Up: Core language

10.2.2.8 What is the difference between arguments and parameters?
.................................................................

*note Parameters: 20ae. are defined by the names that appear in a
function definition, whereas *note arguments: 44c. are the values
actually passed to a function when calling it.  Parameters define what
kind of arguments a function can accept.  For example, given the
function definition:

     def func(foo, bar=None, **kwargs):
         pass

'foo', 'bar' and 'kwargs' are parameters of ‘func’.  However, when
calling ‘func’, for example:

     func(42, bar=314, extra=somevar)

the values ‘42’, ‘314’, and ‘somevar’ are arguments.


File: python.info,  Node: Why did changing list ‘y’ also change list ‘x’?,  Next: How do I write a function with output parameters call by reference ?,  Prev: What is the difference between arguments and parameters?,  Up: Core language

10.2.2.9 Why did changing list ‘y’ also change list ‘x’?
........................................................

If you wrote code like:

     >>> x = []
     >>> y = x
     >>> y.append(10)
     >>> y
     [10]
     >>> x
     [10]

you might be wondering why appending an element to ‘y’ changed ‘x’ too.

There are two factors that produce this result:

  1. Variables are simply names that refer to objects.  Doing ‘y = x’
     doesn’t create a copy of the list – it creates a new variable ‘y’
     that refers to the same object ‘x’ refers to.  This means that
     there is only one object (the list), and both ‘x’ and ‘y’ refer to
     it.

  2. Lists are *note mutable: 1d96, which means that you can change
     their content.

After the call to *note append(): 213c, the content of the mutable
object has changed from ‘[]’ to ‘[10]’.  Since both the variables refer
to the same object, using either name accesses the modified value
‘[10]’.

If we instead assign an immutable object to ‘x’:

     >>> x = 5  # ints are immutable
     >>> y = x
     >>> x = x + 1  # 5 can't be mutated, we are creating a new object here
     >>> x
     6
     >>> y
     5

we can see that in this case ‘x’ and ‘y’ are not equal anymore.  This is
because integers are *note immutable: 1d91, and when we do ‘x = x + 1’
we are not mutating the int ‘5’ by incrementing its value; instead, we
are creating a new object (the int ‘6’) and assigning it to ‘x’ (that
is, changing which object ‘x’ refers to).  After this assignment we have
two objects (the ints ‘6’ and ‘5’) and two variables that refer to them
(‘x’ now refers to ‘6’ but ‘y’ still refers to ‘5’).

Some operations (for example ‘y.append(10)’ and ‘y.sort()’) mutate the
object, whereas superficially similar operations (for example ‘y = y +
[10]’ and *note sorted(y): bed.) create a new object.  In general in
Python (and in all cases in the standard library) a method that mutates
an object will return ‘None’ to help avoid getting the two types of
operations confused.  So if you mistakenly write ‘y.sort()’ thinking it
will give you a sorted copy of ‘y’, you’ll instead end up with ‘None’,
which will likely cause your program to generate an easily diagnosed
error.

However, there is one class of operations where the same operation
sometimes has different behaviors with different types: the augmented
assignment operators.  For example, ‘+=’ mutates lists but not tuples or
ints (‘a_list += [1, 2, 3]’ is equivalent to ‘a_list.extend([1, 2, 3])’
and mutates ‘a_list’, whereas ‘some_tuple += (1, 2, 3)’ and ‘some_int +=
1’ create new objects).

In other words:

   * If we have a mutable object (such as *note list: 614, *note dict:
     256, *note set: 5dc.), we can use some specific operations to
     mutate it and all the variables that refer to it will see the
     change.

   * If we have an immutable object (such as *note str: 44f, *note int:
     257, *note tuple: 373.), all the variables that refer to it will
     always see the same value, but operations that transform that value
     into a new value always return a new object.

If you want to know if two variables refer to the same object or not,
you can use the *note is: 2f5. operator, or the built-in function *note
id(): 1471.


File: python.info,  Node: How do I write a function with output parameters call by reference ?,  Next: How do you make a higher order function in Python?,  Prev: Why did changing list ‘y’ also change list ‘x’?,  Up: Core language

10.2.2.10 How do I write a function with output parameters (call by reference)?
...............................................................................

Remember that arguments are passed by assignment in Python.  Since
assignment just creates references to objects, there’s no alias between
an argument name in the caller and callee, and consequently no
call-by-reference.  You can achieve the desired effect in a number of
ways.

  1. By returning a tuple of the results:

          >>> def func1(a, b):
          ...     a = 'new-value'        # a and b are local names
          ...     b = b + 1              # assigned to new objects
          ...     return a, b            # return new values
          ...
          >>> x, y = 'old-value', 99
          >>> func1(x, y)
          ('new-value', 100)

     This is almost always the clearest solution.

  2. By using global variables.  This isn’t thread-safe, and is not
     recommended.

  3. By passing a mutable (changeable in-place) object:

          >>> def func2(a):
          ...     a[0] = 'new-value'     # 'a' references a mutable list
          ...     a[1] = a[1] + 1        # changes a shared object
          ...
          >>> args = ['old-value', 99]
          >>> func2(args)
          >>> args
          ['new-value', 100]

  4. By passing in a dictionary that gets mutated:

          >>> def func3(args):
          ...     args['a'] = 'new-value'     # args is a mutable dictionary
          ...     args['b'] = args['b'] + 1   # change it in-place
          ...
          >>> args = {'a': 'old-value', 'b': 99}
          >>> func3(args)
          >>> args
          {'a': 'new-value', 'b': 100}

  5. Or bundle up values in a class instance:

          >>> class Namespace:
          ...     def __init__(self, /, **args):
          ...         for key, value in args.items():
          ...             setattr(self, key, value)
          ...
          >>> def func4(args):
          ...     args.a = 'new-value'        # args is a mutable Namespace
          ...     args.b = args.b + 1         # change object in-place
          ...
          >>> args = Namespace(a='old-value', b=99)
          >>> func4(args)
          >>> vars(args)
          {'a': 'new-value', 'b': 100}

     There’s almost never a good reason to get this complicated.

Your best choice is to return a tuple containing the multiple results.


File: python.info,  Node: How do you make a higher order function in Python?,  Next: How do I copy an object in Python?,  Prev: How do I write a function with output parameters call by reference ?,  Up: Core language

10.2.2.11 How do you make a higher order function in Python?
............................................................

You have two choices: you can use nested scopes or you can use callable
objects.  For example, suppose you wanted to define ‘linear(a,b)’ which
returns a function ‘f(x)’ that computes the value ‘a*x+b’.  Using nested
scopes:

     def linear(a, b):
         def result(x):
             return a * x + b
         return result

Or using a callable object:

     class linear:

         def __init__(self, a, b):
             self.a, self.b = a, b

         def __call__(self, x):
             return self.a * x + self.b

In both cases,

     taxes = linear(0.3, 2)

gives a callable object where ‘taxes(10e6) == 0.3 * 10e6 + 2’.

The callable object approach has the disadvantage that it is a bit
slower and results in slightly longer code.  However, note that a
collection of callables can share their signature via inheritance:

     class exponential(linear):
         # __init__ inherited
         def __call__(self, x):
             return self.a * (x ** self.b)

Object can encapsulate state for several methods:

     class counter:

         value = 0

         def set(self, x):
             self.value = x

         def up(self):
             self.value = self.value + 1

         def down(self):
             self.value = self.value - 1

     count = counter()
     inc, dec, reset = count.up, count.down, count.set

Here ‘inc()’, ‘dec()’ and ‘reset()’ act like functions which share the
same counting variable.


File: python.info,  Node: How do I copy an object in Python?,  Next: How can I find the methods or attributes of an object?,  Prev: How do you make a higher order function in Python?,  Up: Core language

10.2.2.12 How do I copy an object in Python?
............................................

In general, try *note copy.copy(): 537. or *note copy.deepcopy(): b8a.
for the general case.  Not all objects can be copied, but most can.

Some objects can be copied more easily.  Dictionaries have a *note
copy(): bef. method:

     newdict = olddict.copy()

Sequences can be copied by slicing:

     new_l = l[:]


File: python.info,  Node: How can I find the methods or attributes of an object?,  Next: How can my code discover the name of an object?,  Prev: How do I copy an object in Python?,  Up: Core language

10.2.2.13 How can I find the methods or attributes of an object?
................................................................

For an instance ‘x’ of a user-defined class, *note dir(x): 635. returns
an alphabetized list of the names containing the instance attributes and
methods and attributes defined by its class.


File: python.info,  Node: How can my code discover the name of an object?,  Next: What’s up with the comma operator’s precedence?,  Prev: How can I find the methods or attributes of an object?,  Up: Core language

10.2.2.14 How can my code discover the name of an object?
.........................................................

Generally speaking, it can’t, because objects don’t really have names.
Essentially, assignment always binds a name to a value; the same is true
of ‘def’ and ‘class’ statements, but in that case the value is a
callable.  Consider the following code:

     >>> class A:
     ...     pass
     ...
     >>> B = A
     >>> a = B()
     >>> b = a
     >>> print(b)
     <__main__.A object at 0x16D07CC>
     >>> print(a)
     <__main__.A object at 0x16D07CC>

Arguably the class has a name: even though it is bound to two names and
invoked through the name ‘B’ the created instance is still reported as
an instance of class ‘A’.  However, it is impossible to say whether the
instance’s name is ‘a’ or ‘b’, since both names are bound to the same
value.

Generally speaking it should not be necessary for your code to “know the
names” of particular values.  Unless you are deliberately writing
introspective programs, this is usually an indication that a change of
approach might be beneficial.

In comp.lang.python, Fredrik Lundh once gave an excellent analogy in
answer to this question:

     The same way as you get the name of that cat you found on your
     porch: the cat (object) itself cannot tell you its name, and it
     doesn’t really care – so the only way to find out what it’s called
     is to ask all your neighbours (namespaces) if it’s their cat
     (object)…

     ….and don’t be surprised if you’ll find that it’s known by many
     names, or no name at all!


File: python.info,  Node: What’s up with the comma operator’s precedence?,  Next: Is there an equivalent of C’s “? ” ternary operator?,  Prev: How can my code discover the name of an object?,  Up: Core language

10.2.2.15 What’s up with the comma operator’s precedence?
.........................................................

Comma is not an operator in Python.  Consider this session:

     >>> "a" in "b", "a"
     (False, 'a')

Since the comma is not an operator, but a separator between expressions
the above is evaluated as if you had entered:

     ("a" in "b"), "a"

not:

     "a" in ("b", "a")

The same is true of the various assignment operators (‘=’, ‘+=’, and so
on).  They are not truly operators but syntactic delimiters in
assignment statements.


File: python.info,  Node: Is there an equivalent of C’s “? ” ternary operator?,  Next: Is it possible to write obfuscated one-liners in Python?,  Prev: What’s up with the comma operator’s precedence?,  Up: Core language

10.2.2.16 Is there an equivalent of C’s “?:” ternary operator?
..............................................................

Yes, there is.  The syntax is as follows:

     [on_true] if [expression] else [on_false]

     x, y = 50, 25
     small = x if x < y else y

Before this syntax was introduced in Python 2.5, a common idiom was to
use logical operators:

     [expression] and [on_true] or [on_false]

However, this idiom is unsafe, as it can give wrong results when
'on_true' has a false boolean value.  Therefore, it is always better to
use the ‘... if ... else ...’ form.


File: python.info,  Node: Is it possible to write obfuscated one-liners in Python?,  Next: What does the slash / in the parameter list of a function mean?,  Prev: Is there an equivalent of C’s “? ” ternary operator?,  Up: Core language

10.2.2.17 Is it possible to write obfuscated one-liners in Python?
..................................................................

Yes.  Usually this is done by nesting *note lambda: 12e4. within
‘lambda’.  See the following three examples, slightly adapted from Ulf
Bartelt:

     from functools import reduce

     # Primes < 1000
     print(list(filter(None,map(lambda y:y*reduce(lambda x,y:x*y!=0,
     map(lambda x,y=y:y%x,range(2,int(pow(y,0.5)+1))),1),range(2,1000)))))

     # First 10 Fibonacci numbers
     print(list(map(lambda x,f=lambda x,f:(f(x-1,f)+f(x-2,f)) if x>1 else 1:
     f(x,f), range(10))))

     # Mandelbrot set
     print((lambda Ru,Ro,Iu,Io,IM,Sx,Sy:reduce(lambda x,y:x+'\n'+y,map(lambda y,
     Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,Sy=Sy,L=lambda yc,Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,i=IM,
     Sx=Sx,Sy=Sy:reduce(lambda x,y:x+y,map(lambda x,xc=Ru,yc=yc,Ru=Ru,Ro=Ro,
     i=i,Sx=Sx,F=lambda xc,yc,x,y,k,f=lambda xc,yc,x,y,k,f:(k<=0)or (x*x+y*y
     >=4.0) or 1+f(xc,yc,x*x-y*y+xc,2.0*x*y+yc,k-1,f):f(xc,yc,x,y,k,f):chr(
     64+F(Ru+x*(Ro-Ru)/Sx,yc,0,0,i)),range(Sx))):L(Iu+y*(Io-Iu)/Sy),range(Sy
     ))))(-2.1, 0.7, -1.2, 1.2, 30, 80, 24))
     #    \___ ___/  \___ ___/  |   |   |__ lines on screen
     #        V          V      |   |______ columns on screen
     #        |          |      |__________ maximum of "iterations"
     #        |          |_________________ range on y axis
     #        |____________________________ range on x axis

Don’t try this at home, kids!


File: python.info,  Node: What does the slash / in the parameter list of a function mean?,  Prev: Is it possible to write obfuscated one-liners in Python?,  Up: Core language

10.2.2.18 What does the slash(/) in the parameter list of a function mean?
..........................................................................

A slash in the argument list of a function denotes that the parameters
prior to it are positional-only.  Positional-only parameters are the
ones without an externally usable name.  Upon calling a function that
accepts positional-only parameters, arguments are mapped to parameters
based solely on their position.  For example, *note divmod(): 9ac. is a
function that accepts positional-only parameters.  Its documentation
looks like this:

     >>> help(divmod)
     Help on built-in function divmod in module builtins:

     divmod(x, y, /)
         Return the tuple (x//y, x%y).  Invariant: div*y + mod == x.

The slash at the end of the parameter list means that both parameters
are positional-only.  Thus, calling *note divmod(): 9ac. with keyword
arguments would lead to an error:

     >>> divmod(x=3, y=4)
     Traceback (most recent call last):
       File "<stdin>", line 1, in <module>
     TypeError: divmod() takes no keyword arguments


File: python.info,  Node: Numbers and strings,  Next: Performance<4>,  Prev: Core language,  Up: Programming FAQ

10.2.3 Numbers and strings
--------------------------

* Menu:

* How do I specify hexadecimal and octal integers?::
* Why does -22 // 10 return -3?::
* How do I get int literal attribute instead of SyntaxError?::
* How do I convert a string to a number?::
* How do I convert a number to a string?::
* How do I modify a string in place?::
* How do I use strings to call functions/methods?::
* Is there an equivalent to Perl’s chomp() for removing trailing newlines from strings?: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?.
* Is there a scanf() or sscanf() equivalent?: Is there a scanf or sscanf equivalent?.
* What does UnicodeDecodeError or UnicodeEncodeError error mean?::
* Can I end a raw string with an odd number of backslashes?::


File: python.info,  Node: How do I specify hexadecimal and octal integers?,  Next: Why does -22 // 10 return -3?,  Up: Numbers and strings

10.2.3.1 How do I specify hexadecimal and octal integers?
.........................................................

To specify an octal digit, precede the octal value with a zero, and then
a lower or uppercase “o”.  For example, to set the variable “a” to the
octal value “10” (8 in decimal), type:

     >>> a = 0o10
     >>> a
     8

Hexadecimal is just as easy.  Simply precede the hexadecimal number with
a zero, and then a lower or uppercase “x”.  Hexadecimal digits can be
specified in lower or uppercase.  For example, in the Python
interpreter:

     >>> a = 0xa5
     >>> a
     165
     >>> b = 0XB2
     >>> b
     178


File: python.info,  Node: Why does -22 // 10 return -3?,  Next: How do I get int literal attribute instead of SyntaxError?,  Prev: How do I specify hexadecimal and octal integers?,  Up: Numbers and strings

10.2.3.2 Why does -22 // 10 return -3?
......................................

It’s primarily driven by the desire that ‘i % j’ have the same sign as
‘j’.  If you want that, and also want:

     i == (i // j) * j + (i % j)

then integer division has to return the floor.  C also requires that
identity to hold, and then compilers that truncate ‘i // j’ need to make
‘i % j’ have the same sign as ‘i’.

There are few real use cases for ‘i % j’ when ‘j’ is negative.  When ‘j’
is positive, there are many, and in virtually all of them it’s more
useful for ‘i % j’ to be ‘>= 0’.  If the clock says 10 now, what did it
say 200 hours ago?  ‘-190 % 12 == 2’ is useful; ‘-190 % 12 == -10’ is a
bug waiting to bite.


File: python.info,  Node: How do I get int literal attribute instead of SyntaxError?,  Next: How do I convert a string to a number?,  Prev: Why does -22 // 10 return -3?,  Up: Numbers and strings

10.2.3.3 How do I get int literal attribute instead of SyntaxError?
...................................................................

Trying to lookup an ‘int’ literal attribute in the normal manner gives a
*note SyntaxError: 18d. because the period is seen as a decimal point:

     >>> 1.__class__
       File "<stdin>", line 1
       1.__class__
        ^
     SyntaxError: invalid decimal literal

The solution is to separate the literal from the period with either a
space or parentheses.

     >>> 1 .__class__
     <class 'int'>
     >>> (1).__class__
     <class 'int'>


File: python.info,  Node: How do I convert a string to a number?,  Next: How do I convert a number to a string?,  Prev: How do I get int literal attribute instead of SyntaxError?,  Up: Numbers and strings

10.2.3.4 How do I convert a string to a number?
...............................................

For integers, use the built-in *note int(): 257. type constructor, for
example, ‘int('144') == 144’.  Similarly, *note float(): 2f7. converts
to a floating-point number, for example, ‘float('144') == 144.0’.

By default, these interpret the number as decimal, so that ‘int('0144')
== 144’ holds true, and ‘int('0x144')’ raises *note ValueError: 202.
‘int(string, base)’ takes the base to convert from as a second optional
argument, so ‘int( '0x144', 16) == 324’.  If the base is specified as 0,
the number is interpreted using Python’s rules: a leading ‘0o’ indicates
octal, and ‘0x’ indicates a hex number.

Do not use the built-in function *note eval(): 180. if all you need is
to convert strings to numbers.  ‘eval()’ will be significantly slower
and it presents a security risk: someone could pass you a Python
expression that might have unwanted side effects.  For example, someone
could pass ‘__import__('os').system("rm -rf $HOME")’ which would erase
your home directory.

*note eval(): 180. also has the effect of interpreting numbers as Python
expressions, so that, for example, ‘eval('09')’ gives a syntax error
because Python does not allow leading ‘0’ in a decimal number (except
‘0’).


File: python.info,  Node: How do I convert a number to a string?,  Next: How do I modify a string in place?,  Prev: How do I convert a string to a number?,  Up: Numbers and strings

10.2.3.5 How do I convert a number to a string?
...............................................

For example, to convert the number ‘144’ to the string ‘'144'’, use the
built-in type constructor *note str(): 44f.  If you want a hexadecimal
or octal representation, use the built-in functions *note hex(): 1317.
or *note oct(): 1316.  For fancy formatting, see the *note f-strings:
9b4. and *note Format string syntax: 13e8. sections.  For example,
‘"{:04d}".format(144)’ yields ‘'0144'’ and ‘"{:.3f}".format(1.0/3.0)’
yields ‘'0.333'’.


File: python.info,  Node: How do I modify a string in place?,  Next: How do I use strings to call functions/methods?,  Prev: How do I convert a number to a string?,  Up: Numbers and strings

10.2.3.6 How do I modify a string in place?
...........................................

You can’t, because strings are immutable.  In most situations, you
should simply construct a new string from the various parts you want to
assemble it from.  However, if you need an object with the ability to
modify in-place Unicode data, try using an *note io.StringIO: f5e.
object or the *note array: 7. module:

     >>> import io
     >>> s = "Hello, world"
     >>> sio = io.StringIO(s)
     >>> sio.getvalue()
     'Hello, world'
     >>> sio.seek(7)
     7
     >>> sio.write("there!")
     6
     >>> sio.getvalue()
     'Hello, there!'

     >>> import array
     >>> a = array.array('w', s)
     >>> print(a)
     array('w', 'Hello, world')
     >>> a[0] = 'y'
     >>> print(a)
     array('w', 'yello, world')
     >>> a.tounicode()
     'yello, world'


File: python.info,  Node: How do I use strings to call functions/methods?,  Next: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?,  Prev: How do I modify a string in place?,  Up: Numbers and strings

10.2.3.7 How do I use strings to call functions/methods?
........................................................

There are various techniques.

   * The best is to use a dictionary that maps strings to functions.
     The primary advantage of this technique is that the strings do not
     need to match the names of the functions.  This is also the primary
     technique used to emulate a case construct:

          def a():
              pass

          def b():
              pass

          dispatch = {'go': a, 'stop': b}  # Note lack of parens for funcs

          dispatch[get_input()]()  # Note trailing parens to call function

   * Use the built-in function *note getattr(): bf0.:

          import foo
          getattr(foo, 'bar')()

     Note that *note getattr(): bf0. works on any object, including
     classes, class instances, modules, and so on.

     This is used in several places in the standard library, like this:

          class Foo:
              def do_foo(self):
                  ...

              def do_bar(self):
                  ...

          f = getattr(foo_instance, 'do_' + opname)
          f()

   * Use *note locals(): 141. to resolve the function name:

          def myFunc():
              print("hello")

          fname = "myFunc"

          f = locals()[fname]
          f()


File: python.info,  Node: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?,  Next: Is there a scanf or sscanf equivalent?,  Prev: How do I use strings to call functions/methods?,  Up: Numbers and strings

10.2.3.8 Is there an equivalent to Perl’s ‘chomp()’ for removing trailing newlines from strings?
................................................................................................

You can use ‘S.rstrip("\r\n")’ to remove all occurrences of any line
terminator from the end of the string ‘S’ without removing other
trailing whitespace.  If the string ‘S’ represents more than one line,
with several empty lines at the end, the line terminators for all the
blank lines will be removed:

     >>> lines = ("line 1 \r\n"
     ...          "\r\n"
     ...          "\r\n")
     >>> lines.rstrip("\n\r")
     'line 1 '

Since this is typically only desired when reading text one line at a
time, using ‘S.rstrip()’ this way works well.


File: python.info,  Node: Is there a scanf or sscanf equivalent?,  Next: What does UnicodeDecodeError or UnicodeEncodeError error mean?,  Prev: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?,  Up: Numbers and strings

10.2.3.9 Is there a ‘scanf()’ or ‘sscanf()’ equivalent?
.......................................................

Not as such.

For simple input parsing, the easiest approach is usually to split the
line into whitespace-delimited words using the *note split(): ede.
method of string objects and then convert decimal strings to numeric
values using *note int(): 257. or *note float(): 2f7.  ‘split()’
supports an optional “sep” parameter which is useful if the line uses
something other than whitespace as a separator.

For more complicated input parsing, regular expressions are more
powerful than C’s ‘sscanf’ and better suited for the task.


File: python.info,  Node: What does UnicodeDecodeError or UnicodeEncodeError error mean?,  Next: Can I end a raw string with an odd number of backslashes?,  Prev: Is there a scanf or sscanf equivalent?,  Up: Numbers and strings

10.2.3.10 What does ‘UnicodeDecodeError’ or ‘UnicodeEncodeError’ error mean?
............................................................................

See the *note Unicode HOWTO: 12ec.


File: python.info,  Node: Can I end a raw string with an odd number of backslashes?,  Prev: What does UnicodeDecodeError or UnicodeEncodeError error mean?,  Up: Numbers and strings

10.2.3.11 Can I end a raw string with an odd number of backslashes?
...................................................................

A raw string ending with an odd number of backslashes will escape the
string’s quote:

     >>> r'C:\this\will\not\work\'
       File "<stdin>", line 1
         r'C:\this\will\not\work\'
         ^
     SyntaxError: unterminated string literal (detected at line 1)

There are several workarounds for this.  One is to use regular strings
and double the backslashes:

     >>> 'C:\\this\\will\\work\\'
     'C:\\this\\will\\work\\'

Another is to concatenate a regular string containing an escaped
backslash to the raw string:

     >>> r'C:\this\will\work' '\\'
     'C:\\this\\will\\work\\'

It is also possible to use *note os.path.join(): 173c. to append a
backslash on Windows:

     >>> os.path.join(r'C:\this\will\work', '')
     'C:\\this\\will\\work\\'

Note that while a backslash will “escape” a quote for the purposes of
determining where the raw string ends, no escaping occurs when
interpreting the value of the raw string.  That is, the backslash
remains present in the value of the raw string:

     >>> r'backslash\'preserved'
     "backslash\\'preserved"

Also see the specification in the *note language reference: 2050.


File: python.info,  Node: Performance<4>,  Next: Sequences tuples/lists,  Prev: Numbers and strings,  Up: Programming FAQ

10.2.4 Performance
------------------

* Menu:

* My program is too slow. How do I speed it up?: My program is too slow How do I speed it up?.
* What is the most efficient way to concatenate many strings together?::


File: python.info,  Node: My program is too slow How do I speed it up?,  Next: What is the most efficient way to concatenate many strings together?,  Up: Performance<4>

10.2.4.1 My program is too slow. How do I speed it up?
......................................................

That’s a tough one, in general.  First, here is a list of things to
remember before diving further:

   * Performance characteristics vary across Python implementations.
     This FAQ focuses on *note CPython: 6f9.

   * Behaviour can vary across operating systems, especially when
     talking about I/O or multi-threading.

   * You should always find the hot spots in your program 'before'
     attempting to optimize any code (see the *note profile: af.
     module).

   * Writing benchmark scripts will allow you to iterate quickly when
     searching for improvements (see the *note timeit: ef. module).

   * It is highly recommended to have good code coverage (through unit
     testing or any other technique) before potentially introducing
     regressions hidden in sophisticated optimizations.

That being said, there are many tricks to speed up Python code.  Here
are some general principles which go a long way towards reaching
acceptable performance levels:

   * Making your algorithms faster (or changing to faster ones) can
     yield much larger benefits than trying to sprinkle
     micro-optimization tricks all over your code.

   * Use the right data structures.  Study documentation for the *note
     Built-in Types: 2345. and the *note collections: 1d. module.

   * When the standard library provides a primitive for doing something,
     it is likely (although not guaranteed) to be faster than any
     alternative you may come up with.  This is doubly true for
     primitives written in C, such as builtins and some extension types.
     For example, be sure to use either the *note list.sort(): bee.
     built-in method or the related *note sorted(): bed. function to do
     sorting (and see the *note Sorting Techniques: 2337. for examples
     of moderately advanced usage).

   * Abstractions tend to create indirections and force the interpreter
     to work more.  If the levels of indirection outweigh the amount of
     useful work done, your program will be slower.  You should avoid
     excessive abstraction, especially under the form of tiny functions
     or methods (which are also often detrimental to readability).

If you have reached the limit of what pure Python can allow, there are
tools to take you further away.  For example, Cython(1) can compile a
slightly modified version of Python code into a C extension, and can be
used on many different platforms.  Cython can take advantage of
compilation (and optional type annotations) to make your code
significantly faster than when interpreted.  If you are confident in
your C programming skills, you can also *note write a C extension
module: 1d6e. yourself.

See also
........

The wiki page devoted to performance tips(2).

   ---------- Footnotes ----------

   (1) https://cython.org

   (2) https://wiki.python.org/moin/PythonSpeed/PerformanceTips


File: python.info,  Node: What is the most efficient way to concatenate many strings together?,  Prev: My program is too slow How do I speed it up?,  Up: Performance<4>

10.2.4.2 What is the most efficient way to concatenate many strings together?
.............................................................................

*note str: 44f. and *note bytes: 1c2. objects are immutable, therefore
concatenating many strings together is inefficient as each concatenation
creates a new object.  In the general case, the total runtime cost is
quadratic in the total string length.

To accumulate many *note str: 44f. objects, the recommended idiom is to
place them into a list and call *note str.join(): 2363. at the end:

     chunks = []
     for s in my_strings:
         chunks.append(s)
     result = ''.join(chunks)

(Another reasonably efficient idiom is to use *note io.StringIO: f5e.)

To accumulate many *note bytes: 1c2. objects, the recommended idiom is
to extend a *note bytearray: 2ea. object using in-place concatenation
(the ‘+=’ operator):

     result = bytearray()
     for b in my_bytes_objects:
         result += b


File: python.info,  Node: Sequences tuples/lists,  Next: Objects,  Prev: Performance<4>,  Up: Programming FAQ

10.2.5 Sequences (tuples/lists)
-------------------------------

* Menu:

* How do I convert between tuples and lists?::
* What’s a negative index?::
* How do I iterate over a sequence in reverse order?::
* How do you remove duplicates from a list?::
* How do you remove multiple items from a list?::
* How do you make an array in Python?::
* How do I create a multidimensional list?::
* How do I apply a method or function to a sequence of objects?::
* Why does a_tuple[i] += [‘item’] raise an exception when the addition works?::
* I want to do a complicated sort; can you do a Schwartzian Transform in Python?: I want to do a complicated sort can you do a Schwartzian Transform in Python?.
* How can I sort one list by values from another list?::


File: python.info,  Node: How do I convert between tuples and lists?,  Next: What’s a negative index?,  Up: Sequences tuples/lists

10.2.5.1 How do I convert between tuples and lists?
...................................................

The type constructor ‘tuple(seq)’ converts any sequence (actually, any
iterable) into a tuple with the same items in the same order.

For example, ‘tuple([1, 2, 3])’ yields ‘(1, 2, 3)’ and ‘tuple('abc')’
yields ‘('a', 'b', 'c')’.  If the argument is a tuple, it does not make
a copy but returns the same object, so it is cheap to call *note
tuple(): 373. when you aren’t sure that an object is already a tuple.

The type constructor ‘list(seq)’ converts any sequence or iterable into
a list with the same items in the same order.  For example, ‘list((1, 2,
3))’ yields ‘[1, 2, 3]’ and ‘list('abc')’ yields ‘['a', 'b', 'c']’.  If
the argument is a list, it makes a copy just like ‘seq[:]’ would.


File: python.info,  Node: What’s a negative index?,  Next: How do I iterate over a sequence in reverse order?,  Prev: How do I convert between tuples and lists?,  Up: Sequences tuples/lists

10.2.5.2 What’s a negative index?
.................................

Python sequences are indexed with positive numbers and negative numbers.
For positive numbers 0 is the first index 1 is the second index and so
forth.  For negative indices -1 is the last index and -2 is the
penultimate (next to last) index and so forth.  Think of ‘seq[-n]’ as
the same as ‘seq[len(seq)-n]’.

Using negative indices can be very convenient.  For example ‘S[:-1]’ is
all of the string except for its last character, which is useful for
removing the trailing newline from a string.


File: python.info,  Node: How do I iterate over a sequence in reverse order?,  Next: How do you remove duplicates from a list?,  Prev: What’s a negative index?,  Up: Sequences tuples/lists

10.2.5.3 How do I iterate over a sequence in reverse order?
...........................................................

Use the *note reversed(): 86c. built-in function:

     for x in reversed(sequence):
         ...  # do something with x ...

This won’t touch your original sequence, but build a new copy with
reversed order to iterate over.


File: python.info,  Node: How do you remove duplicates from a list?,  Next: How do you remove multiple items from a list?,  Prev: How do I iterate over a sequence in reverse order?,  Up: Sequences tuples/lists

10.2.5.4 How do you remove duplicates from a list?
..................................................

See the Python Cookbook for a long discussion of many ways to do this:

     ‘https://code.activestate.com/recipes/52560/’

If you don’t mind reordering the list, sort it and then scan from the
end of the list, deleting duplicates as you go:

     if mylist:
         mylist.sort()
         last = mylist[-1]
         for i in range(len(mylist)-2, -1, -1):
             if last == mylist[i]:
                 del mylist[i]
             else:
                 last = mylist[i]

If all elements of the list may be used as set keys (that is, they are
all *note hashable: 613.) this is often faster:

     mylist = list(set(mylist))

This converts the list into a set, thereby removing duplicates, and then
back into a list.


File: python.info,  Node: How do you remove multiple items from a list?,  Next: How do you make an array in Python?,  Prev: How do you remove duplicates from a list?,  Up: Sequences tuples/lists

10.2.5.5 How do you remove multiple items from a list?
......................................................

As with removing duplicates, explicitly iterating in reverse with a
delete condition is one possibility.  However, it is easier and faster
to use slice replacement with an implicit or explicit forward iteration.
Here are three variations:

     mylist[:] = filter(keep_function, mylist)
     mylist[:] = (x for x in mylist if keep_condition)
     mylist[:] = [x for x in mylist if keep_condition]

The list comprehension may be fastest.


File: python.info,  Node: How do you make an array in Python?,  Next: How do I create a multidimensional list?,  Prev: How do you remove multiple items from a list?,  Up: Sequences tuples/lists

10.2.5.6 How do you make an array in Python?
............................................

Use a list:

     ["this", 1, "is", "an", "array"]

Lists are equivalent to C or Pascal arrays in their time complexity; the
primary difference is that a Python list can contain objects of many
different types.

The ‘array’ module also provides methods for creating arrays of fixed
types with compact representations, but they are slower to index than
lists.  Also note that NumPy(1) and other third-party packages define
array-like structures with various characteristics as well.

To get Lisp-style linked lists, you can emulate 'cons cells' using
tuples:

     lisp_list = ("like",  ("this",  ("example", None) ) )

If mutability is desired, you could use lists instead of tuples.  Here
the analogue of a Lisp 'car' is ‘lisp_list[0]’ and the analogue of 'cdr'
is ‘lisp_list[1]’.  Only do this if you’re sure you really need to,
because it’s usually a lot slower than using Python lists.

   ---------- Footnotes ----------

   (1) https://numpy.org/


File: python.info,  Node: How do I create a multidimensional list?,  Next: How do I apply a method or function to a sequence of objects?,  Prev: How do you make an array in Python?,  Up: Sequences tuples/lists

10.2.5.7 How do I create a multidimensional list?
.................................................

You probably tried to make a multidimensional array like this:

     >>> A = [[None] * 2] * 3

This looks correct if you print it:

     >>> A
     [[None, None], [None, None], [None, None]]

But when you assign a value, it shows up in multiple places:

     >>> A[0][0] = 5
     >>> A
     [[5, None], [5, None], [5, None]]

The reason is that replicating a list with ‘*’ doesn’t create copies, it
only creates references to the existing objects.  The ‘*3’ creates a
list containing 3 references to the same list of length two.  Changes to
one row will show in all rows, which is almost certainly not what you
want.

The suggested approach is to create a list of the desired length first
and then fill in each element with a newly created list:

     A = [None] * 3
     for i in range(3):
         A[i] = [None] * 2

This generates a list containing 3 different lists of length two.  You
can also use a list comprehension:

     w, h = 2, 3
     A = [[None] * w for i in range(h)]

Or, you can use an extension that provides a matrix datatype; NumPy(1)
is the best known.

   ---------- Footnotes ----------

   (1) https://numpy.org/


File: python.info,  Node: How do I apply a method or function to a sequence of objects?,  Next: Why does a_tuple[i] += [‘item’] raise an exception when the addition works?,  Prev: How do I create a multidimensional list?,  Up: Sequences tuples/lists

10.2.5.8 How do I apply a method or function to a sequence of objects?
......................................................................

To call a method or function and accumulate the return values in a list,
a *note list comprehension: 6d1. is an elegant solution:

     result = [obj.method() for obj in mylist]

     result = [function(obj) for obj in mylist]

To just run the method or function without saving the return values, a
plain *note for: 2f2. loop will suffice:

     for obj in mylist:
         obj.method()

     for obj in mylist:
         function(obj)


File: python.info,  Node: Why does a_tuple[i] += [‘item’] raise an exception when the addition works?,  Next: I want to do a complicated sort can you do a Schwartzian Transform in Python?,  Prev: How do I apply a method or function to a sequence of objects?,  Up: Sequences tuples/lists

10.2.5.9 Why does a_tuple[i] += [‘item’] raise an exception when the addition works?
....................................................................................

This is because of a combination of the fact that augmented assignment
operators are 'assignment' operators, and the difference between mutable
and immutable objects in Python.

This discussion applies in general when augmented assignment operators
are applied to elements of a tuple that point to mutable objects, but
we’ll use a ‘list’ and ‘+=’ as our exemplar.

If you wrote:

     >>> a_tuple = (1, 2)
     >>> a_tuple[0] += 1
     Traceback (most recent call last):
        ...
     TypeError: 'tuple' object does not support item assignment

The reason for the exception should be immediately clear: ‘1’ is added
to the object ‘a_tuple[0]’ points to (‘1’), producing the result object,
‘2’, but when we attempt to assign the result of the computation, ‘2’,
to element ‘0’ of the tuple, we get an error because we can’t change
what an element of a tuple points to.

Under the covers, what this augmented assignment statement is doing is
approximately this:

     >>> result = a_tuple[0] + 1
     >>> a_tuple[0] = result
     Traceback (most recent call last):
       ...
     TypeError: 'tuple' object does not support item assignment

It is the assignment part of the operation that produces the error,
since a tuple is immutable.

When you write something like:

     >>> a_tuple = (['foo'], 'bar')
     >>> a_tuple[0] += ['item']
     Traceback (most recent call last):
       ...
     TypeError: 'tuple' object does not support item assignment

The exception is a bit more surprising, and even more surprising is the
fact that even though there was an error, the append worked:

     >>> a_tuple[0]
     ['foo', 'item']

To see why this happens, you need to know that (a) if an object
implements an *note __iadd__(): 2147. magic method, it gets called when
the ‘+=’ augmented assignment is executed, and its return value is what
gets used in the assignment statement; and (b) for lists, ‘__iadd__()’
is equivalent to calling *note extend(): 213f. on the list and returning
the list.  That’s why we say that for lists, ‘+=’ is a “shorthand” for
*note list.extend(): 360.:

     >>> a_list = []
     >>> a_list += [1]
     >>> a_list
     [1]

This is equivalent to:

     >>> result = a_list.__iadd__([1])
     >>> a_list = result

The object pointed to by a_list has been mutated, and the pointer to the
mutated object is assigned back to ‘a_list’.  The end result of the
assignment is a no-op, since it is a pointer to the same object that
‘a_list’ was previously pointing to, but the assignment still happens.

Thus, in our tuple example what is happening is equivalent to:

     >>> result = a_tuple[0].__iadd__(['item'])
     >>> a_tuple[0] = result
     Traceback (most recent call last):
       ...
     TypeError: 'tuple' object does not support item assignment

The ‘__iadd__()’ succeeds, and thus the list is extended, but even
though ‘result’ points to the same object that ‘a_tuple[0]’ already
points to, that final assignment still results in an error, because
tuples are immutable.


File: python.info,  Node: I want to do a complicated sort can you do a Schwartzian Transform in Python?,  Next: How can I sort one list by values from another list?,  Prev: Why does a_tuple[i] += [‘item’] raise an exception when the addition works?,  Up: Sequences tuples/lists

10.2.5.10 I want to do a complicated sort: can you do a Schwartzian Transform in Python?
........................................................................................

The technique, attributed to Randal Schwartz of the Perl community,
sorts the elements of a list by a metric which maps each element to its
“sort value”.  In Python, use the ‘key’ argument for the *note
list.sort(): bee. method:

     Isorted = L[:]
     Isorted.sort(key=lambda s: int(s[10:15]))


File: python.info,  Node: How can I sort one list by values from another list?,  Prev: I want to do a complicated sort can you do a Schwartzian Transform in Python?,  Up: Sequences tuples/lists

10.2.5.11 How can I sort one list by values from another list?
..............................................................

Merge them into an iterator of tuples, sort the resulting list, and then
pick out the element you want.

     >>> list1 = ["what", "I'm", "sorting", "by"]
     >>> list2 = ["something", "else", "to", "sort"]
     >>> pairs = zip(list1, list2)
     >>> pairs = sorted(pairs)
     >>> pairs
     [("I'm", 'else'), ('by', 'sort'), ('sorting', 'to'), ('what', 'something')]
     >>> result = [x[1] for x in pairs]
     >>> result
     ['else', 'sort', 'to', 'something']


File: python.info,  Node: Objects,  Next: Modules<5>,  Prev: Sequences tuples/lists,  Up: Programming FAQ

10.2.6 Objects
--------------

* Menu:

* What is a class?::
* What is a method?::
* What is self?::
* How do I check if an object is an instance of a given class or of a subclass of it?::
* What is delegation?::
* How do I call a method defined in a base class from a derived class that extends it?::
* How can I organize my code to make it easier to change the base class?::
* How do I create static class data and static class methods?::
* How can I overload constructors (or methods) in Python?: How can I overload constructors or methods in Python?.
* I try to use __spam and I get an error about _SomeClassName__spam.: I try to use __spam and I get an error about _SomeClassName__spam.
* My class defines __del__ but it is not called when I delete the object.: My class defines __del__ but it is not called when I delete the object.
* How do I get a list of all instances of a given class?::
* Why does the result of id() appear to be not unique?: Why does the result of id appear to be not unique?.
* When can I rely on identity tests with the is operator?::
* How can a subclass control what data is stored in an immutable instance?::
* How do I cache method calls?::


File: python.info,  Node: What is a class?,  Next: What is a method?,  Up: Objects

10.2.6.1 What is a class?
.........................

A class is the particular object type created by executing a class
statement.  Class objects are used as templates to create instance
objects, which embody both the data (attributes) and code (methods)
specific to a datatype.

A class can be based on one or more other classes, called its base
class(es).  It then inherits the attributes and methods of its base
classes.  This allows an object model to be successively refined by
inheritance.  You might have a generic ‘Mailbox’ class that provides
basic accessor methods for a mailbox, and subclasses such as
‘MboxMailbox’, ‘MaildirMailbox’, ‘OutlookMailbox’ that handle various
specific mailbox formats.


File: python.info,  Node: What is a method?,  Next: What is self?,  Prev: What is a class?,  Up: Objects

10.2.6.2 What is a method?
..........................

A method is a function on some object ‘x’ that you normally call as
‘x.name(arguments...)’.  Methods are defined as functions inside the
class definition:

     class C:
         def meth(self, arg):
             return arg * 2 + self.attribute


File: python.info,  Node: What is self?,  Next: How do I check if an object is an instance of a given class or of a subclass of it?,  Prev: What is a method?,  Up: Objects

10.2.6.3 What is self?
......................

Self is merely a conventional name for the first argument of a method.
A method defined as ‘meth(self, a, b, c)’ should be called as ‘x.meth(a,
b, c)’ for some instance ‘x’ of the class in which the definition
occurs; the called method will think it is called as ‘meth(x, a, b, c)’.

See also *note Why must ‘self’ be used explicitly in method definitions
and calls?: 556d.


File: python.info,  Node: How do I check if an object is an instance of a given class or of a subclass of it?,  Next: What is delegation?,  Prev: What is self?,  Up: Objects

10.2.6.4 How do I check if an object is an instance of a given class or of a subclass of it?
............................................................................................

Use the built-in function *note isinstance(obj, cls): 445.  You can
check if an object is an instance of any of a number of classes by
providing a tuple instead of a single class, for example,
‘isinstance(obj, (class1, class2, ...))’, and can also check whether an
object is one of Python’s built-in types, for example, ‘isinstance(obj,
str)’ or ‘isinstance(obj, (int, float, complex))’.

Note that *note isinstance(): 445. also checks for virtual inheritance
from an *note abstract base class: 11fa.  So, the test will return
‘True’ for a registered class even if hasn’t directly or indirectly
inherited from it.  To test for “true inheritance”, scan the *note
method resolution order: 2339. (MRO) of the class:

     from collections.abc import Mapping

     class P:
          pass

     class C(P):
         pass

     Mapping.register(P)

     >>> c = C()
     >>> isinstance(c, C)        # direct
     True
     >>> isinstance(c, P)        # indirect
     True
     >>> isinstance(c, Mapping)  # virtual
     True

     # Actual inheritance chain
     >>> type(c).__mro__
     (<class 'C'>, <class 'P'>, <class 'object'>)

     # Test for "true inheritance"
     >>> Mapping in type(c).__mro__
     False

Note that most programs do not use *note isinstance(): 445. on
user-defined classes very often.  If you are developing the classes
yourself, a more proper object-oriented style is to define methods on
the classes that encapsulate a particular behaviour, instead of checking
the object’s class and doing a different thing based on what class it
is.  For example, if you have a function that does something:

     def search(obj):
         if isinstance(obj, Mailbox):
             ...  # code to search a mailbox
         elif isinstance(obj, Document):
             ...  # code to search a document
         elif ...

A better approach is to define a ‘search()’ method on all the classes
and just call it:

     class Mailbox:
         def search(self):
             ...  # code to search a mailbox

     class Document:
         def search(self):
             ...  # code to search a document

     obj.search()


File: python.info,  Node: What is delegation?,  Next: How do I call a method defined in a base class from a derived class that extends it?,  Prev: How do I check if an object is an instance of a given class or of a subclass of it?,  Up: Objects

10.2.6.5 What is delegation?
............................

Delegation is an object-oriented technique (also called a design
pattern).  Let’s say you have an object ‘x’ and want to change the
behaviour of just one of its methods.  You can create a new class that
provides a new implementation of the method you’re interested in
changing and delegates all other methods to the corresponding method of
‘x’.

Python programmers can easily implement delegation.  For example, the
following class implements a class that behaves like a file but converts
all written data to uppercase:

     class UpperOut:

         def __init__(self, outfile):
             self._outfile = outfile

         def write(self, s):
             self._outfile.write(s.upper())

         def __getattr__(self, name):
             return getattr(self._outfile, name)

Here the ‘UpperOut’ class redefines the ‘write()’ method to convert the
argument string to uppercase before calling the underlying
‘self._outfile.write()’ method.  All other methods are delegated to the
underlying ‘self._outfile’ object.  The delegation is accomplished via
the *note __getattr__(): 4d6. method; consult *note the language
reference: 2115. for more information about controlling attribute
access.

Note that for more general cases delegation can get trickier.  When
attributes must be set as well as retrieved, the class must define a
*note __setattr__(): 20de. method too, and it must do so carefully.  The
basic implementation of ‘__setattr__()’ is roughly equivalent to the
following:

     class X:
         ...
         def __setattr__(self, name, value):
             self.__dict__[name] = value
         ...

Many *note __setattr__(): 20de. implementations call
‘object.__setattr__()’ to set an attribute on self without causing
infinite recursion:

     class X:
         def __setattr__(self, name, value):
             # Custom logic here...
             object.__setattr__(self, name, value)

Alternatively, it is possible to set attributes by inserting entries
into *note self.__dict__: 55e. directly.


File: python.info,  Node: How do I call a method defined in a base class from a derived class that extends it?,  Next: How can I organize my code to make it easier to change the base class?,  Prev: What is delegation?,  Up: Objects

10.2.6.6 How do I call a method defined in a base class from a derived class that extends it?
.............................................................................................

Use the built-in *note super(): 4de. function:

     class Derived(Base):
         def meth(self):
             super().meth()  # calls Base.meth

In the example, *note super(): 4de. will automatically determine the
instance from which it was called (the ‘self’ value), look up the *note
method resolution order: 2339. (MRO) with ‘type(self).__mro__’, and
return the next in line after ‘Derived’ in the MRO: ‘Base’.


File: python.info,  Node: How can I organize my code to make it easier to change the base class?,  Next: How do I create static class data and static class methods?,  Prev: How do I call a method defined in a base class from a derived class that extends it?,  Up: Objects

10.2.6.7 How can I organize my code to make it easier to change the base class?
...............................................................................

You could assign the base class to an alias and derive from the alias.
Then all you have to change is the value assigned to the alias.
Incidentally, this trick is also handy if you want to decide dynamically
(such as depending on availability of resources) which base class to
use.  Example:

     class Base:
         ...

     BaseAlias = Base

     class Derived(BaseAlias):
         ...


File: python.info,  Node: How do I create static class data and static class methods?,  Next: How can I overload constructors or methods in Python?,  Prev: How can I organize my code to make it easier to change the base class?,  Up: Objects

10.2.6.8 How do I create static class data and static class methods?
....................................................................

Both static data and static methods (in the sense of C++ or Java) are
supported in Python.

For static data, simply define a class attribute.  To assign a new value
to the attribute, you have to explicitly use the class name in the
assignment:

     class C:
         count = 0   # number of times C.__init__ called

         def __init__(self):
             C.count = C.count + 1

         def getcount(self):
             return C.count  # or return self.count

‘c.count’ also refers to ‘C.count’ for any ‘c’ such that ‘isinstance(c,
C)’ holds, unless overridden by ‘c’ itself or by some class on the
base-class search path from ‘c.__class__’ back to ‘C’.

Caution: within a method of C, an assignment like ‘self.count = 42’
creates a new and unrelated instance named “count” in ‘self’’s own dict.
Rebinding of a class-static data name must always specify the class
whether inside a method or not:

     C.count = 314

Static methods are possible:

     class C:
         @staticmethod
         def static(arg1, arg2, arg3):
             # No 'self' parameter!
             ...

However, a far more straightforward way to get the effect of a static
method is via a simple module-level function:

     def getcount():
         return C.count

If your code is structured so as to define one class (or tightly related
class hierarchy) per module, this supplies the desired encapsulation.


File: python.info,  Node: How can I overload constructors or methods in Python?,  Next: I try to use __spam and I get an error about _SomeClassName__spam,  Prev: How do I create static class data and static class methods?,  Up: Objects

10.2.6.9 How can I overload constructors (or methods) in Python?
................................................................

This answer actually applies to all methods, but the question usually
comes up first in the context of constructors.

In C++ you’d write:

     class C {
         C() { cout << "No arguments\n"; }
         C(int i) { cout << "Argument is " << i << "\n"; }
     }

In Python you have to write a single constructor that catches all cases
using default arguments.  For example:

     class C:
         def __init__(self, i=None):
             if i is None:
                 print("No arguments")
             else:
                 print("Argument is", i)

This is not entirely equivalent, but close enough in practice.

You could also try a variable-length argument list, for example:

     def __init__(self, *args):
         ...

The same approach works for all method definitions.


File: python.info,  Node: I try to use __spam and I get an error about _SomeClassName__spam,  Next: My class defines __del__ but it is not called when I delete the object,  Prev: How can I overload constructors or methods in Python?,  Up: Objects

10.2.6.10 I try to use __spam and I get an error about _SomeClassName__spam.
............................................................................

Variable names with double leading underscores are “mangled” to provide
a simple but effective way to define class private variables.  Any
identifier of the form ‘__spam’ (at least two leading underscores, at
most one trailing underscore) is textually replaced with
‘_classname__spam’, where ‘classname’ is the current class name with any
leading underscores stripped.

The identifier can be used unchanged within the class, but to access it
outside the class, the mangled name must be used:

     class A:
         def __one(self):
             return 1
         def two(self):
             return 2 * self.__one()

     class B(A):
         def three(self):
             return 3 * self._A__one()

     four = 4 * A()._A__one()

In particular, this does not guarantee privacy since an outside user can
still deliberately access the private attribute; many Python programmers
never bother to use private variable names at all.

See also
........

The *note private name mangling specifications: 1e5b. for details and
special cases.


File: python.info,  Node: My class defines __del__ but it is not called when I delete the object,  Next: How do I get a list of all instances of a given class?,  Prev: I try to use __spam and I get an error about _SomeClassName__spam,  Up: Objects

10.2.6.11 My class defines __del__ but it is not called when I delete the object.
.................................................................................

There are several possible reasons for this.

The *note del: 18c2. statement does not necessarily call *note
__del__(): 1038. – it simply decrements the object’s reference count,
and if this reaches zero ‘__del__()’ is called.

If your data structures contain circular links (for example, a tree
where each child has a parent reference and each parent has a list of
children) the reference counts will never go back to zero.  Once in a
while Python runs an algorithm to detect such cycles, but the garbage
collector might run some time after the last reference to your data
structure vanishes, so your ‘__del__()’ method may be called at an
inconvenient and random time.  This is inconvenient if you’re trying to
reproduce a problem.  Worse, the order in which object’s ‘__del__()’
methods are executed is arbitrary.  You can run *note gc.collect(): a47.
to force a collection, but there 'are' pathological cases where objects
will never be collected.

Despite the cycle collector, it’s still a good idea to define an
explicit ‘close()’ method on objects to be called whenever you’re done
with them.  The ‘close()’ method can then remove attributes that refer
to subobjects.  Don’t call ‘__del__()’ directly – ‘__del__()’ should
call ‘close()’ and ‘close()’ should make sure that it can be called more
than once for the same object.

Another way to avoid cyclical references is to use the *note weakref:
114. module, which allows you to point to objects without incrementing
their reference count.  Tree data structures, for instance, should use
weak references for their parent and sibling references (if they need
them!).

Finally, if your ‘__del__()’ method raises an exception, a warning
message is printed to *note sys.stderr: 943.


File: python.info,  Node: How do I get a list of all instances of a given class?,  Next: Why does the result of id appear to be not unique?,  Prev: My class defines __del__ but it is not called when I delete the object,  Up: Objects

10.2.6.12 How do I get a list of all instances of a given class?
................................................................

Python does not keep track of all instances of a class (or of a built-in
type).  You can program the class’s constructor to keep track of all
instances by keeping a list of weak references to each instance.


File: python.info,  Node: Why does the result of id appear to be not unique?,  Next: When can I rely on identity tests with the is operator?,  Prev: How do I get a list of all instances of a given class?,  Up: Objects

10.2.6.13 Why does the result of ‘id()’ appear to be not unique?
................................................................

The *note id(): 1471. builtin returns an integer that is guaranteed to
be unique during the lifetime of the object.  Since in CPython, this is
the object’s memory address, it happens frequently that after an object
is deleted from memory, the next freshly created object is allocated at
the same position in memory.  This is illustrated by this example:

     >>> id(1000)
     13901272
     >>> id(2000)
     13901272

The two ids belong to different integer objects that are created before,
and deleted immediately after execution of the ‘id()’ call.  To be sure
that objects whose id you want to examine are still alive, create
another reference to the object:

     >>> a = 1000; b = 2000
     >>> id(a)
     13901272
     >>> id(b)
     13891296


File: python.info,  Node: When can I rely on identity tests with the is operator?,  Next: How can a subclass control what data is stored in an immutable instance?,  Prev: Why does the result of id appear to be not unique?,  Up: Objects

10.2.6.14 When can I rely on identity tests with the 'is' operator?
...................................................................

The ‘is’ operator tests for object identity.  The test ‘a is b’ is
equivalent to ‘id(a) == id(b)’.

The most important property of an identity test is that an object is
always identical to itself, ‘a is a’ always returns ‘True’.  Identity
tests are usually faster than equality tests.  And unlike equality
tests, identity tests are guaranteed to return a boolean ‘True’ or
‘False’.

However, identity tests can 'only' be substituted for equality tests
when object identity is assured.  Generally, there are three
circumstances where identity is guaranteed:

  1. Assignments create new names but do not change object identity.
     After the assignment ‘new = old’, it is guaranteed that ‘new is
     old’.

  2. Putting an object in a container that stores object references does
     not change object identity.  After the list assignment ‘s[0] = x’,
     it is guaranteed that ‘s[0] is x’.

  3. If an object is a singleton, it means that only one instance of
     that object can exist.  After the assignments ‘a = None’ and ‘b =
     None’, it is guaranteed that ‘a is b’ because ‘None’ is a
     singleton.

In most other circumstances, identity tests are inadvisable and equality
tests are preferred.  In particular, identity tests should not be used
to check constants such as *note int: 257. and *note str: 44f. which
aren’t guaranteed to be singletons:

     >>> a = 10_000_000
     >>> b = 5_000_000
     >>> c = b + 5_000_000
     >>> a is c
     False

     >>> a = 'Python'
     >>> b = 'Py'
     >>> c = b + 'thon'
     >>> a is c
     False

Likewise, new instances of mutable containers are never identical:

     >>> a = []
     >>> b = []
     >>> a is b
     False

In the standard library code, you will see several common patterns for
correctly using identity tests:

  1. As recommended by PEP 8(1), an identity test is the preferred way
     to check for ‘None’.  This reads like plain English in code and
     avoids confusion with other objects that may have boolean values
     that evaluate to false.

  2. Detecting optional arguments can be tricky when ‘None’ is a valid
     input value.  In those situations, you can create a singleton
     sentinel object guaranteed to be distinct from other objects.  For
     example, here is how to implement a method that behaves like *note
     dict.pop(): 344.:

          _sentinel = object()

          def pop(self, key, default=_sentinel):
              if key in self:
                  value = self[key]
                  del self[key]
                  return value
              if default is _sentinel:
                  raise KeyError(key)
              return default

  3. Container implementations sometimes need to augment equality tests
     with identity tests.  This prevents the code from being confused by
     objects such as ‘float('NaN')’ that are not equal to themselves.

For example, here is the implementation of
‘collections.abc.Sequence.__contains__()’:

     def __contains__(self, value):
         for v in self:
             if v is value or v == value:
                 return True
         return False

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: How can a subclass control what data is stored in an immutable instance?,  Next: How do I cache method calls?,  Prev: When can I rely on identity tests with the is operator?,  Up: Objects

10.2.6.15 How can a subclass control what data is stored in an immutable instance?
..................................................................................

When subclassing an immutable type, override the *note __new__(): 583.
method instead of the *note __init__(): 6b3. method.  The latter only
runs 'after' an instance is created, which is too late to alter data in
an immutable instance.

All of these immutable classes have a different signature than their
parent class:

     import datetime as dt

     class FirstOfMonthDate(dt.date):
         "Always choose the first day of the month"
         def __new__(cls, year, month, day):
             return super().__new__(cls, year, month, 1)

     class NamedInt(int):
         "Allow text names for some numbers"
         xlat = {'zero': 0, 'one': 1, 'ten': 10}
         def __new__(cls, value):
             value = cls.xlat.get(value, value)
             return super().__new__(cls, value)

     class TitleStr(str):
         "Convert str to name suitable for a URL path"
         def __new__(cls, s):
             s = s.lower().replace(' ', '-')
             s = ''.join([c for c in s if c.isalnum() or c == '-'])
             return super().__new__(cls, s)

The classes can be used like this:

     >>> FirstOfMonthDate(2012, 2, 14)
     FirstOfMonthDate(2012, 2, 1)
     >>> NamedInt('ten')
     10
     >>> NamedInt(20)
     20
     >>> TitleStr('Blog: Why Python Rocks')
     'blog-why-python-rocks'


File: python.info,  Node: How do I cache method calls?,  Prev: How can a subclass control what data is stored in an immutable instance?,  Up: Objects

10.2.6.16 How do I cache method calls?
......................................

The two principal tools for caching methods are *note
functools.cached_property(): 544. and *note functools.lru_cache(): 9fa.
The former stores results at the instance level and the latter at the
class level.

The ‘cached_property’ approach only works with methods that do not take
any arguments.  It does not create a reference to the instance.  The
cached method result will be kept only as long as the instance is alive.

The advantage is that when an instance is no longer used, the cached
method result will be released right away.  The disadvantage is that if
instances accumulate, so too will the accumulated method results.  They
can grow without bound.

The ‘lru_cache’ approach works with methods that have *note hashable:
613. arguments.  It creates a reference to the instance unless special
efforts are made to pass in weak references.

The advantage of the least recently used algorithm is that the cache is
bounded by the specified 'maxsize'.  The disadvantage is that instances
are kept alive until they age out of the cache or until the cache is
cleared.

This example shows the various techniques:

     class Weather:
         "Lookup weather information on a government website"

         def __init__(self, station_id):
             self._station_id = station_id
             # The _station_id is private and immutable

         def current_temperature(self):
             "Latest hourly observation"
             # Do not cache this because old results
             # can be out of date.

         @cached_property
         def location(self):
             "Return the longitude/latitude coordinates of the station"
             # Result only depends on the station_id

         @lru_cache(maxsize=20)
         def historic_rainfall(self, date, units='mm'):
             "Rainfall on a given date"
             # Depends on the station_id, date, and units.

The above example assumes that the 'station_id' never changes.  If the
relevant instance attributes are mutable, the ‘cached_property’ approach
can’t be made to work because it cannot detect changes to the
attributes.

To make the ‘lru_cache’ approach work when the 'station_id' is mutable,
the class needs to define the *note __eq__(): b13. and *note __hash__():
b14. methods so that the cache can detect relevant attribute updates:

     class Weather:
         "Example with a mutable station identifier"

         def __init__(self, station_id):
             self.station_id = station_id

         def change_station(self, station_id):
             self.station_id = station_id

         def __eq__(self, other):
             return self.station_id == other.station_id

         def __hash__(self):
             return hash(self.station_id)

         @lru_cache(maxsize=20)
         def historic_rainfall(self, date, units='cm'):
             'Rainfall on a given date'
             # Depends on the station_id, date, and units.


File: python.info,  Node: Modules<5>,  Prev: Objects,  Up: Programming FAQ

10.2.7 Modules
--------------

* Menu:

* How do I create a .pyc file?: How do I create a pyc file?.
* How do I find the current module name?::
* How can I have modules that mutually import each other?::
* __import__(‘x.y.z’) returns <module ‘x’>; how do I get z?: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?.
* When I edit an imported module and reimport it, the changes don’t show up. Why does this happen?: When I edit an imported module and reimport it the changes don’t show up Why does this happen?.


File: python.info,  Node: How do I create a pyc file?,  Next: How do I find the current module name?,  Up: Modules<5>

10.2.7.1 How do I create a .pyc file?
.....................................

When a module is imported for the first time (or when the source file
has changed since the current compiled file was created) a ‘.pyc’ file
containing the compiled code should be created in a ‘__pycache__’
subdirectory of the directory containing the ‘.py’ file.  The ‘.pyc’
file will have a filename that starts with the same name as the ‘.py’
file, and ends with ‘.pyc’, with a middle component that depends on the
particular ‘python’ binary that created it.  (See PEP 3147(1) for
details.)

One reason that a ‘.pyc’ file may not be created is a permissions
problem with the directory containing the source file, meaning that the
‘__pycache__’ subdirectory cannot be created.  This can happen, for
example, if you develop as one user but run as another, such as if you
are testing with a web server.

Unless the *note PYTHONDONTWRITEBYTECODE: 141c. environment variable is
set, creation of a .pyc file is automatic if you’re importing a module
and Python has the ability (permissions, free space, and so on) to
create a ‘__pycache__’ subdirectory and write the compiled module to
that subdirectory.

Running Python on a top-level script is not considered an import and no
‘.pyc’ will be created.  For example, if you have a top-level module
‘foo.py’ that imports another module ‘xyz.py’, when you run ‘foo’ (by
typing ‘python foo.py’ as a shell command), a ‘.pyc’ will be created for
‘xyz’ because ‘xyz’ is imported, but no ‘.pyc’ file will be created for
‘foo’ since ‘foo.py’ isn’t being imported.

If you need to create a ‘.pyc’ file for ‘foo’ – that is, to create a
‘.pyc’ file for a module that is not imported – you can, using the *note
py_compile: b3. and *note compileall: 20. modules.

The *note py_compile: b3. module can manually compile any module.  One
way is to use the ‘compile()’ function in that module interactively:

     >>> import py_compile
     >>> py_compile.compile('foo.py')

This will write the ‘.pyc’ to a ‘__pycache__’ subdirectory in the same
location as ‘foo.py’ (or you can override that with the optional
parameter 'cfile').

You can also automatically compile all files in a directory or
directories using the *note compileall: 20. module.  You can do it from
the shell prompt by running ‘compileall.py’ and providing the path of a
directory containing Python files to compile:

     python -m compileall .

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-3147/


File: python.info,  Node: How do I find the current module name?,  Next: How can I have modules that mutually import each other?,  Prev: How do I create a pyc file?,  Up: Modules<5>

10.2.7.2 How do I find the current module name?
...............................................

A module can find out its own module name by looking at the predefined
global variable ‘__name__’.  If this has the value ‘'__main__'’, the
program is running as a script.  Many modules that are usually used by
importing them also provide a command-line interface or a self-test, and
only execute this code after checking ‘__name__’:

     def main():
         print('Running test...')
         ...

     if __name__ == '__main__':
         main()


File: python.info,  Node: How can I have modules that mutually import each other?,  Next: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?,  Prev: How do I find the current module name?,  Up: Modules<5>

10.2.7.3 How can I have modules that mutually import each other?
................................................................

Suppose you have the following modules:

‘foo.py’:

     from bar import bar_var
     foo_var = 1

‘bar.py’:

     from foo import foo_var
     bar_var = 2

The problem is that the interpreter will perform the following steps:

   * main imports ‘foo’

   * Empty globals for ‘foo’ are created

   * ‘foo’ is compiled and starts executing

   * ‘foo’ imports ‘bar’

   * Empty globals for ‘bar’ are created

   * ‘bar’ is compiled and starts executing

   * ‘bar’ imports ‘foo’ (which is a no-op since there already is a
     module named ‘foo’)

   * The import mechanism tries to read ‘foo_var’ from ‘foo’ globals, to
     set ‘bar.foo_var = foo.foo_var’

The last step fails, because Python isn’t done with interpreting ‘foo’
yet and the global symbol dictionary for ‘foo’ is still empty.

The same thing happens when you use ‘import foo’, and then try to access
‘foo.foo_var’ in global code.

There are (at least) three possible workarounds for this problem.

Guido van Rossum recommends avoiding all uses of ‘from <module> import
...’, and placing all code inside functions.  Initializations of global
variables and class variables should use constants or built-in functions
only.  This means everything from an imported module is referenced as
‘<module>.<name>’.

Jim Roskind suggests performing steps in the following order in each
module:

   * exports (globals, functions, and classes that don’t need imported
     base classes)

   * ‘import’ statements

   * active code (including globals that are initialized from imported
     values).

Van Rossum doesn’t like this approach much because the imports appear in
a strange place, but it does work.

Matthias Urlichs recommends restructuring your code so that the
recursive import is not necessary in the first place.

These solutions are not mutually exclusive.


File: python.info,  Node: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?,  Next: When I edit an imported module and reimport it the changes don’t show up Why does this happen?,  Prev: How can I have modules that mutually import each other?,  Up: Modules<5>

10.2.7.4 __import__(‘x.y.z’) returns <module ‘x’>; how do I get z?
..................................................................

Consider using the convenience function *note import_module(): 51b. from
*note importlib: 77. instead:

     z = importlib.import_module('x.y.z')


File: python.info,  Node: When I edit an imported module and reimport it the changes don’t show up Why does this happen?,  Prev: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?,  Up: Modules<5>

10.2.7.5 When I edit an imported module and reimport it, the changes don’t show up. Why does this happen?
.........................................................................................................

For reasons of efficiency as well as consistency, Python only reads the
module file on the first time a module is imported.  If it didn’t, in a
program consisting of many modules where each one imports the same basic
module, the basic module would be parsed and re-parsed many times.  To
force re-reading of a changed module, do this:

     import importlib
     import modname
     importlib.reload(modname)

Warning: this technique is not 100% fool-proof.  In particular, modules
containing statements like:

     from modname import some_objects

will continue to work with the old version of the imported objects.  If
the module contains class definitions, existing class instances will
'not' be updated to use the new class definition.  This can result in
the following paradoxical behaviour:

     >>> import importlib
     >>> import cls
     >>> c = cls.C()                # Create an instance of C
     >>> importlib.reload(cls)
     <module 'cls' from 'cls.py'>
     >>> isinstance(c, cls.C)       # isinstance is false?!?
     False

The nature of the problem is made clear if you print out the “identity”
of the class objects:

     >>> hex(id(c.__class__))
     '0x7352a0'
     >>> hex(id(cls.C))
     '0x4198d0'


File: python.info,  Node: Design and History FAQ,  Next: Library and Extension FAQ,  Prev: Programming FAQ,  Up: Python Frequently Asked Questions

10.3 Design and History FAQ
===========================

* Menu:

* Why does Python use indentation for grouping of statements?::
* Why am I getting strange results with simple arithmetic operations?::
* Why are floating-point calculations so inaccurate?::
* Why are Python strings immutable?::
* Why must ‘self’ be used explicitly in method definitions and calls?::
* Why can’t I use an assignment in an expression?::
* Why does Python use methods for some functionality (e.g. list.index()) but functions for other (e.g. len(list))?: Why does Python use methods for some functionality e g list index but functions for other e g len list ?.
* Why is join() a string method instead of a list or tuple method?: Why is join a string method instead of a list or tuple method?.
* How fast are exceptions?::
* Why isn’t there a switch or case statement in Python?::
* Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?::
* Why can’t lambda expressions contain statements?::
* Can Python be compiled to machine code, C or some other language?: Can Python be compiled to machine code C or some other language?.
* How does Python manage memory?::
* Why doesn’t CPython use a more traditional garbage collection scheme?::
* Why isn’t all memory freed when CPython exits?::
* Why are there separate tuple and list data types?::
* How are lists implemented in CPython?::
* How are dictionaries implemented in CPython?::
* Why must dictionary keys be immutable?::
* Why doesn’t list.sort() return the sorted list?: Why doesn’t list sort return the sorted list?.
* How do you specify and enforce an interface spec in Python?::
* Why is there no goto?::
* Why can’t raw strings (r-strings) end with a backslash?: Why can’t raw strings r-strings end with a backslash?.
* Why doesn’t Python have a “with” statement for attribute assignments?::
* Why don’t generators support the with statement?::
* Why are colons required for the if/while/def/class statements?::
* Why does Python allow commas at the end of lists and tuples?::


File: python.info,  Node: Why does Python use indentation for grouping of statements?,  Next: Why am I getting strange results with simple arithmetic operations?,  Up: Design and History FAQ

10.3.1 Why does Python use indentation for grouping of statements?
------------------------------------------------------------------

Guido van Rossum believes that using indentation for grouping is
extremely elegant and contributes a lot to the clarity of the average
Python program.  Most people learn to love this feature after a while.

Since there are no begin/end brackets there cannot be a disagreement
between grouping perceived by the parser and the human reader.
Occasionally C programmers will encounter a fragment of code like this:

     if (x <= y)
             x++;
             y--;
     z++;

Only the ‘x++’ statement is executed if the condition is true, but the
indentation leads many to believe otherwise.  Even experienced C
programmers will sometimes stare at it a long time wondering as to why
‘y’ is being decremented even for ‘x > y’.

Because there are no begin/end brackets, Python is much less prone to
coding-style conflicts.  In C there are many different ways to place the
braces.  After becoming used to reading and writing code using a
particular style, it is normal to feel somewhat uneasy when reading (or
being required to write) in a different one.

Many coding styles place begin/end brackets on a line by themselves.
This makes programs considerably longer and wastes valuable screen
space, making it harder to get a good overview of a program.  Ideally, a
function should fit on one screen (say, 20–30 lines).  20 lines of
Python can do a lot more work than 20 lines of C. This is not solely due
to the lack of begin/end brackets – the lack of declarations and the
high-level data types are also responsible – but the indentation-based
syntax certainly helps.


File: python.info,  Node: Why am I getting strange results with simple arithmetic operations?,  Next: Why are floating-point calculations so inaccurate?,  Prev: Why does Python use indentation for grouping of statements?,  Up: Design and History FAQ

10.3.2 Why am I getting strange results with simple arithmetic operations?
--------------------------------------------------------------------------

See the next question.


File: python.info,  Node: Why are floating-point calculations so inaccurate?,  Next: Why are Python strings immutable?,  Prev: Why am I getting strange results with simple arithmetic operations?,  Up: Design and History FAQ

10.3.3 Why are floating-point calculations so inaccurate?
---------------------------------------------------------

Users are often surprised by results like this:

     >>> 1.2 - 1.0
     0.19999999999999996

and think it is a bug in Python.  It’s not.  This has little to do with
Python, and much more to do with how the underlying platform handles
floating-point numbers.

The *note float: 2f7. type in CPython uses a C ‘double’ for storage.  A
‘float’ object’s value is stored in binary floating-point with a fixed
precision (typically 53 bits) and Python uses C operations, which in
turn rely on the hardware implementation in the processor, to perform
floating-point operations.  This means that as far as floating-point
operations are concerned, Python behaves like many popular languages
including C and Java.

Many numbers that can be written easily in decimal notation cannot be
expressed exactly in binary floating point.  For example, after:

     >>> x = 1.2

the value stored for ‘x’ is a (very good) approximation to the decimal
value ‘1.2’, but is not exactly equal to it.  On a typical machine, the
actual stored value is:

     1.0011001100110011001100110011001100110011001100110011 (binary)

which is exactly:

     1.1999999999999999555910790149937383830547332763671875 (decimal)

The typical precision of 53 bits provides Python floats with 15–16
decimal digits of accuracy.

For a fuller explanation, please see the *note floating-point
arithmetic: 1eb8. chapter in the Python tutorial.


File: python.info,  Node: Why are Python strings immutable?,  Next: Why must ‘self’ be used explicitly in method definitions and calls?,  Prev: Why are floating-point calculations so inaccurate?,  Up: Design and History FAQ

10.3.4 Why are Python strings immutable?
----------------------------------------

There are several advantages.

One is performance: knowing that a string is immutable means we can
allocate space for it at creation time, and the storage requirements are
fixed and unchanging.  This is also one of the reasons for the
distinction between tuples and lists.

Another advantage is that strings in Python are considered as
“elemental” as numbers.  No amount of activity will change the value 8
to anything else, and in Python, no amount of activity will change the
string “eight” to anything else.


File: python.info,  Node: Why must ‘self’ be used explicitly in method definitions and calls?,  Next: Why can’t I use an assignment in an expression?,  Prev: Why are Python strings immutable?,  Up: Design and History FAQ

10.3.5 Why must ‘self’ be used explicitly in method definitions and calls?
--------------------------------------------------------------------------

The idea was borrowed from Modula-3.  It turns out to be very useful,
for a variety of reasons.

First, it’s more obvious that you are using a method or instance
attribute instead of a local variable.  Reading ‘self.x’ or
‘self.meth()’ makes it absolutely clear that an instance variable or
method is used even if you don’t know the class definition by heart.  In
C++, you can sort of tell by the lack of a local variable declaration
(assuming globals are rare or easily recognizable) – but in Python,
there are no local variable declarations, so you’d have to look up the
class definition to be sure.  Some C++ and Java coding standards call
for instance attributes to have an ‘m_’ prefix, so this explicitness is
still useful in those languages, too.

Second, it means that no special syntax is necessary if you want to
explicitly reference or call the method from a particular class.  In
C++, if you want to use a method from a base class which is overridden
in a derived class, you have to use the ‘::’ operator – in Python you
can write ‘baseclass.methodname(self, <argument list>)’.  This is
particularly useful for *note __init__(): 6b3. methods, and in general
in cases where a derived class method wants to extend the base class
method of the same name and thus has to call the base class method
somehow.

Finally, for instance variables it solves a syntactic problem with
assignment: since local variables in Python are (by definition!)  those
variables to which a value is assigned in a function body (and that
aren’t explicitly declared global), there has to be some way to tell the
interpreter that an assignment was meant to assign to an instance
variable instead of to a local variable, and it should preferably be
syntactic (for efficiency reasons).  C++ does this through declarations,
but Python doesn’t have declarations and it would be a pity having to
introduce them just for this purpose.  Using the explicit ‘self.var’
solves this nicely.  Similarly, for using instance variables, having to
write ‘self.var’ means that references to unqualified names inside a
method don’t have to search the instance’s directories.  To put it
another way, local variables and instance variables live in two
different namespaces, and you need to tell Python which namespace to
use.


File: python.info,  Node: Why can’t I use an assignment in an expression?,  Next: Why does Python use methods for some functionality e g list index but functions for other e g len list ?,  Prev: Why must ‘self’ be used explicitly in method definitions and calls?,  Up: Design and History FAQ

10.3.6 Why can’t I use an assignment in an expression?
------------------------------------------------------

Starting in Python 3.8, you can!

Assignment expressions using the walrus operator ‘:=’ assign a variable
in an expression:

     while chunk := fp.read(200):
        print(chunk)

See PEP 572(1) for more information.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0572/


File: python.info,  Node: Why does Python use methods for some functionality e g list index but functions for other e g len list ?,  Next: Why is join a string method instead of a list or tuple method?,  Prev: Why can’t I use an assignment in an expression?,  Up: Design and History FAQ

10.3.7 Why does Python use methods for some functionality (e.g. list.index()) but functions for other (e.g. len(list))?
-----------------------------------------------------------------------------------------------------------------------

As Guido said:

     (a) For some operations, prefix notation just reads better than
     postfix – prefix (and infix!)  operations have a long tradition in
     mathematics which likes notations where the visuals help the
     mathematician thinking about a problem.  Compare the easy with
     which we rewrite a formula like x*(a+b) into x*a + x*b to the
     clumsiness of doing the same thing using a raw OO notation.

     (b) When I read code that says len(x) I 'know' that it is asking
     for the length of something.  This tells me two things: the result
     is an integer, and the argument is some kind of container.  To the
     contrary, when I read x.len(), I have to already know that x is
     some kind of container implementing an interface or inheriting from
     a class that has a standard len().  Witness the confusion we
     occasionally have when a class that is not implementing a mapping
     has a get() or keys() method, or something that isn’t a file has a
     write() method.

-- ‘https://mail.python.org/pipermail/python-3000/2006-November/004643.html’


File: python.info,  Node: Why is join a string method instead of a list or tuple method?,  Next: How fast are exceptions?,  Prev: Why does Python use methods for some functionality e g list index but functions for other e g len list ?,  Up: Design and History FAQ

10.3.8 Why is join() a string method instead of a list or tuple method?
-----------------------------------------------------------------------

Strings became much more like other standard types starting in Python
1.6, when methods were added which give the same functionality that has
always been available using the functions of the string module.  Most of
these new methods have been widely accepted, but the one which appears
to make some programmers feel uncomfortable is:

     ", ".join(['1', '2', '4', '8', '16'])

which gives the result:

     "1, 2, 4, 8, 16"

There are two common arguments against this usage.

The first runs along the lines of: “It looks really ugly using a method
of a string literal (string constant)”, to which the answer is that it
might, but a string literal is just a fixed value.  If the methods are
to be allowed on names bound to strings there is no logical reason to
make them unavailable on literals.

The second objection is typically cast as: “I am really telling a
sequence to join its members together with a string constant”.  Sadly,
you aren’t.  For some reason there seems to be much less difficulty with
having *note split(): ede. as a string method, since in that case it is
easy to see that

     "1, 2, 4, 8, 16".split(", ")

is an instruction to a string literal to return the substrings delimited
by the given separator (or, by default, arbitrary runs of white space).

*note join(): 2363. is a string method because in using it you are
telling the separator string to iterate over a sequence of strings and
insert itself between adjacent elements.  This method can be used with
any argument which obeys the rules for sequence objects, including any
new classes you might define yourself.  Similar methods exist for bytes
and bytearray objects.


File: python.info,  Node: How fast are exceptions?,  Next: Why isn’t there a switch or case statement in Python?,  Prev: Why is join a string method instead of a list or tuple method?,  Up: Design and History FAQ

10.3.9 How fast are exceptions?
-------------------------------

A *note try: 6ec./*note except: 18b. block is extremely efficient if no
exceptions are raised.  Actually catching an exception is expensive.  In
versions of Python prior to 2.0 it was common to use this idiom:

     try:
         value = mydict[key]
     except KeyError:
         mydict[key] = getvalue(key)
         value = mydict[key]

This only made sense when you expected the dict to have the key almost
all the time.  If that wasn’t the case, you coded it like this:

     if key in mydict:
         value = mydict[key]
     else:
         value = mydict[key] = getvalue(key)

For this specific case, you could also use ‘value = dict.setdefault(key,
getvalue(key))’, but only if the ‘getvalue()’ call is cheap enough
because it is evaluated in all cases.


File: python.info,  Node: Why isn’t there a switch or case statement in Python?,  Next: Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?,  Prev: How fast are exceptions?,  Up: Design and History FAQ

10.3.10 Why isn’t there a switch or case statement in Python?
-------------------------------------------------------------

In general, structured switch statements execute one block of code when
an expression has a particular value or set of values.  Since Python
3.10 one can easily match literal values, or constants within a
namespace, with a ‘match ... case’ statement.  An older alternative is a
sequence of ‘if... elif... elif... else’.

For cases where you need to choose from a very large number of
possibilities, you can create a dictionary mapping case values to
functions to call.  For example:

     functions = {'a': function_1,
                  'b': function_2,
                  'c': self.method_1}

     func = functions[value]
     func()

For calling methods on objects, you can simplify yet further by using
the *note getattr(): bf0. built-in to retrieve methods with a particular
name:

     class MyVisitor:
         def visit_a(self):
             ...

         def dispatch(self, value):
             method_name = 'visit_' + str(value)
             method = getattr(self, method_name)
             method()

It’s suggested that you use a prefix for the method names, such as
‘visit_’ in this example.  Without such a prefix, if values are coming
from an untrusted source, an attacker would be able to call any method
on your object.

Imitating switch with fallthrough, as with C’s switch-case-default, is
possible, much harder, and less needed.


File: python.info,  Node: Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?,  Next: Why can’t lambda expressions contain statements?,  Prev: Why isn’t there a switch or case statement in Python?,  Up: Design and History FAQ

10.3.11 Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?
----------------------------------------------------------------------------------------------------------------

Answer 1: Unfortunately, the interpreter pushes at least one C stack
frame for each Python stack frame.  Also, extensions can call back into
Python at almost random moments.  Therefore, a complete threads
implementation requires thread support for C.

Answer 2: Fortunately, there is Stackless Python(1), which has a
completely redesigned interpreter loop that avoids the C stack.

   ---------- Footnotes ----------

   (1) https://github.com/stackless-dev/stackless/wiki


File: python.info,  Node: Why can’t lambda expressions contain statements?,  Next: Can Python be compiled to machine code C or some other language?,  Prev: Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?,  Up: Design and History FAQ

10.3.12 Why can’t lambda expressions contain statements?
--------------------------------------------------------

Python lambda expressions cannot contain statements because Python’s
syntactic framework can’t handle statements nested inside expressions.
However, in Python, this is not a serious problem.  Unlike lambda forms
in other languages, where they add functionality, Python lambdas are
only a shorthand notation if you’re too lazy to define a function.

Functions are already first class objects in Python, and can be declared
in a local scope.  Therefore the only advantage of using a lambda
instead of a locally defined function is that you don’t need to invent a
name for the function – but that’s just a local variable to which the
function object (which is exactly the same type of object that a lambda
expression yields) is assigned!


File: python.info,  Node: Can Python be compiled to machine code C or some other language?,  Next: How does Python manage memory?,  Prev: Why can’t lambda expressions contain statements?,  Up: Design and History FAQ

10.3.13 Can Python be compiled to machine code, C or some other language?
-------------------------------------------------------------------------

Cython(1) compiles a modified version of Python with optional
annotations into C extensions.  Nuitka(2) is an up-and-coming compiler
of Python into C++ code, aiming to support the full Python language.

   ---------- Footnotes ----------

   (1) https://cython.org/

   (2) https://nuitka.net/


File: python.info,  Node: How does Python manage memory?,  Next: Why doesn’t CPython use a more traditional garbage collection scheme?,  Prev: Can Python be compiled to machine code C or some other language?,  Up: Design and History FAQ

10.3.14 How does Python manage memory?
--------------------------------------

The details of Python memory management depend on the implementation.
The standard implementation of Python, *note CPython: 6f9, uses
reference counting to detect inaccessible objects, and another mechanism
to collect reference cycles, periodically executing a cycle detection
algorithm which looks for inaccessible cycles and deletes the objects
involved.  The *note gc: 60. module provides functions to perform a
garbage collection, obtain debugging statistics, and tune the
collector’s parameters.

Other implementations (such as Jython(1) or PyPy(2)), however, can rely
on a different mechanism such as a full-blown garbage collector.  This
difference can cause some subtle porting problems if your Python code
depends on the behavior of the reference counting implementation.

In some Python implementations, the following code (which is fine in
CPython) will probably run out of file descriptors:

     for file in very_long_list_of_files:
         f = open(file)
         c = f.read(1)

Indeed, using CPython’s reference counting and destructor scheme, each
new assignment to ‘f’ closes the previous file.  With a traditional GC,
however, those file objects will only get collected (and closed) at
varying and possibly long intervals.

If you want to write code that will work with any Python implementation,
you should explicitly close the file or use the *note with: 5d5.
statement; this will work regardless of memory management scheme:

     for file in very_long_list_of_files:
         with open(file) as f:
             c = f.read(1)

   ---------- Footnotes ----------

   (1) https://www.jython.org

   (2) https://pypy.org


File: python.info,  Node: Why doesn’t CPython use a more traditional garbage collection scheme?,  Next: Why isn’t all memory freed when CPython exits?,  Prev: How does Python manage memory?,  Up: Design and History FAQ

10.3.15 Why doesn’t CPython use a more traditional garbage collection scheme?
-----------------------------------------------------------------------------

For one thing, this is not a C standard feature and hence it’s not
portable.  (Yes, we know about the Boehm GC library.  It has bits of
assembler code for 'most' common platforms, not for all of them, and
although it is mostly transparent, it isn’t completely transparent;
patches are required to get Python to work with it.)

Traditional GC also becomes a problem when Python is embedded into other
applications.  While in a standalone Python it’s fine to replace the
standard ‘malloc()’ and ‘free()’ with versions provided by the GC
library, an application embedding Python may want to have its 'own'
substitute for ‘malloc()’ and ‘free()’, and may not want Python’s.
Right now, CPython works with anything that implements ‘malloc()’ and
‘free()’ properly.


File: python.info,  Node: Why isn’t all memory freed when CPython exits?,  Next: Why are there separate tuple and list data types?,  Prev: Why doesn’t CPython use a more traditional garbage collection scheme?,  Up: Design and History FAQ

10.3.16 Why isn’t all memory freed when CPython exits?
------------------------------------------------------

Objects referenced from the global namespaces of Python modules are not
always deallocated when Python exits.  This may happen if there are
circular references.  There are also certain bits of memory that are
allocated by the C library that are impossible to free (e.g.  a tool
like Purify will complain about these).  Python is, however, aggressive
about cleaning up memory on exit and does try to destroy every single
object.

If you want to force Python to delete certain things on deallocation use
the *note atexit: c. module to run a function that will force those
deletions.


File: python.info,  Node: Why are there separate tuple and list data types?,  Next: How are lists implemented in CPython?,  Prev: Why isn’t all memory freed when CPython exits?,  Up: Design and History FAQ

10.3.17 Why are there separate tuple and list data types?
---------------------------------------------------------

Lists and tuples, while similar in many respects, are generally used in
fundamentally different ways.  Tuples can be thought of as being similar
to Pascal ‘records’ or C ‘structs’; they’re small collections of related
data which may be of different types which are operated on as a group.
For example, a Cartesian coordinate is appropriately represented as a
tuple of two or three numbers.

Lists, on the other hand, are more like arrays in other languages.  They
tend to hold a varying number of objects all of which have the same type
and which are operated on one-by-one.  For example, *note
os.listdir('.'): 113e. returns a list of strings representing the files
in the current directory.  Functions which operate on this output would
generally not break if you added another file or two to the directory.

Tuples are immutable, meaning that once a tuple has been created, you
can’t replace any of its elements with a new value.  Lists are mutable,
meaning that you can always change a list’s elements.  Only immutable
elements can be used as dictionary keys, and hence only tuples and not
lists can be used as keys.


File: python.info,  Node: How are lists implemented in CPython?,  Next: How are dictionaries implemented in CPython?,  Prev: Why are there separate tuple and list data types?,  Up: Design and History FAQ

10.3.18 How are lists implemented in CPython?
---------------------------------------------

CPython’s lists are really variable-length arrays, not Lisp-style linked
lists.  The implementation uses a contiguous array of references to
other objects, and keeps a pointer to this array and the array’s length
in a list head structure.

This makes indexing a list ‘a[i]’ an operation whose cost is independent
of the size of the list or the value of the index.

When items are appended or inserted, the array of references is resized.
Some cleverness is applied to improve the performance of appending items
repeatedly; when the array must be grown, some extra space is allocated
so the next few times don’t require an actual resize.


File: python.info,  Node: How are dictionaries implemented in CPython?,  Next: Why must dictionary keys be immutable?,  Prev: How are lists implemented in CPython?,  Up: Design and History FAQ

10.3.19 How are dictionaries implemented in CPython?
----------------------------------------------------

CPython’s dictionaries are implemented as resizable hash tables.
Compared to B-trees, this gives better performance for lookup (the most
common operation by far) under most circumstances, and the
implementation is simpler.

Dictionaries work by computing a hash code for each key stored in the
dictionary using the *note hash(): 5ee. built-in function.  The hash
code varies widely depending on the key and a per-process seed; for
example, ‘'Python'’ could hash to ‘-539294296’ while ‘'python'’, a
string that differs by a single bit, could hash to ‘1142331976’.  The
hash code is then used to calculate a location in an internal array
where the value will be stored.  Assuming that you’re storing keys that
all have different hash values, this means that dictionaries take
constant time – 'O'(1), in Big-O notation – to retrieve a key.


File: python.info,  Node: Why must dictionary keys be immutable?,  Next: Why doesn’t list sort return the sorted list?,  Prev: How are dictionaries implemented in CPython?,  Up: Design and History FAQ

10.3.20 Why must dictionary keys be immutable?
----------------------------------------------

The hash table implementation of dictionaries uses a hash value
calculated from the key value to find the key.  If the key were a
mutable object, its value could change, and thus its hash could also
change.  But since whoever changes the key object can’t tell that it was
being used as a dictionary key, it can’t move the entry around in the
dictionary.  Then, when you try to look up the same object in the
dictionary it won’t be found because its hash value is different.  If
you tried to look up the old value it wouldn’t be found either, because
the value of the object found in that hash bin would be different.

If you want a dictionary indexed with a list, simply convert the list to
a tuple first; the function ‘tuple(L)’ creates a tuple with the same
entries as the list ‘L’.  Tuples are immutable and can therefore be used
as dictionary keys.

Some unacceptable solutions that have been proposed:

   - Hash lists by their address (object ID). This doesn’t work because
     if you construct a new list with the same value it won’t be found;
     e.g.:

          mydict = {[1, 2]: '12'}
          print(mydict[[1, 2]])

     would raise a *note KeyError: 345. exception because the id of the
     ‘[1, 2]’ used in the second line differs from that in the first
     line.  In other words, dictionary keys should be compared using
     ‘==’, not using *note is: 2f5.

   - Make a copy when using a list as a key.  This doesn’t work because
     the list, being a mutable object, could contain a reference to
     itself, and then the copying code would run into an infinite loop.

   - Allow lists as keys but tell the user not to modify them.  This
     would allow a class of hard-to-track bugs in programs when you
     forgot or modified a list by accident.  It also invalidates an
     important invariant of dictionaries: every value in ‘d.keys()’ is
     usable as a key of the dictionary.

   - Mark lists as read-only once they are used as a dictionary key.
     The problem is that it’s not just the top-level object that could
     change its value; you could use a tuple containing a list as a key.
     Entering anything as a key into a dictionary would require marking
     all objects reachable from there as read-only – and again,
     self-referential objects could cause an infinite loop.

There is a trick to get around this if you need to, but use it at your
own risk: You can wrap a mutable structure inside a class instance which
has both a *note __eq__(): b13. and a *note __hash__(): b14. method.
You must then make sure that the hash value for all such wrapper objects
that reside in a dictionary (or other hash based structure), remain
fixed while the object is in the dictionary (or other structure).

     class ListWrapper:
         def __init__(self, the_list):
             self.the_list = the_list

         def __eq__(self, other):
             return self.the_list == other.the_list

         def __hash__(self):
             l = self.the_list
             result = 98767 - len(l)*555
             for i, el in enumerate(l):
                 try:
                     result = result + (hash(el) % 9999999) * 1001 + i
                 except Exception:
                     result = (result % 7777777) + i * 333
             return result

Note that the hash computation is complicated by the possibility that
some members of the list may be unhashable and also by the possibility
of arithmetic overflow.

Furthermore it must always be the case that if ‘o1 == o2’ (ie
‘o1.__eq__(o2) is True’) then ‘hash(o1) == hash(o2)’ (ie, ‘o1.__hash__()
== o2.__hash__()’), regardless of whether the object is in a dictionary
or not.  If you fail to meet these restrictions dictionaries and other
hash based structures will misbehave.

In the case of ‘ListWrapper’, whenever the wrapper object is in a
dictionary the wrapped list must not change to avoid anomalies.  Don’t
do this unless you are prepared to think hard about the requirements and
the consequences of not meeting them correctly.  Consider yourself
warned.


File: python.info,  Node: Why doesn’t list sort return the sorted list?,  Next: How do you specify and enforce an interface spec in Python?,  Prev: Why must dictionary keys be immutable?,  Up: Design and History FAQ

10.3.21 Why doesn’t list.sort() return the sorted list?
-------------------------------------------------------

In situations where performance matters, making a copy of the list just
to sort it would be wasteful.  Therefore, *note list.sort(): bee. sorts
the list in place.  In order to remind you of that fact, it does not
return the sorted list.  This way, you won’t be fooled into accidentally
overwriting a list when you need a sorted copy but also need to keep the
unsorted version around.

If you want to return a new list, use the built-in *note sorted(): bed.
function instead.  This function creates a new list from a provided
iterable, sorts it and returns it.  For example, here’s how to iterate
over the keys of a dictionary in sorted order:

     for key in sorted(mydict):
         ...  # do whatever with mydict[key]...


File: python.info,  Node: How do you specify and enforce an interface spec in Python?,  Next: Why is there no goto?,  Prev: Why doesn’t list sort return the sorted list?,  Up: Design and History FAQ

10.3.22 How do you specify and enforce an interface spec in Python?
-------------------------------------------------------------------

An interface specification for a module as provided by languages such as
C++ and Java describes the prototypes for the methods and functions of
the module.  Many feel that compile-time enforcement of interface
specifications helps in the construction of large programs.

Python 2.6 adds an *note abc: 4. module that lets you define Abstract
Base Classes (ABCs).  You can then use *note isinstance(): 445. and
*note issubclass(): 7c5. to check whether an instance or a class
implements a particular ABC. The *note collections.abc: 1e. module
defines a set of useful ABCs such as *note Iterable: 2405, *note
Container: 2407, and *note MutableMapping: 10f0.

For Python, many of the advantages of interface specifications can be
obtained by an appropriate test discipline for components.

A good test suite for a module can both provide a regression test and
serve as a module interface specification and a set of examples.  Many
Python modules can be run as a script to provide a simple “self test.”
Even modules which use complex external interfaces can often be tested
in isolation using trivial “stub” emulations of the external interface.
The *note doctest: 3a. and *note unittest: 106. modules or third-party
test frameworks can be used to construct exhaustive test suites that
exercise every line of code in a module.

An appropriate testing discipline can help build large complex
applications in Python as well as having interface specifications would.
In fact, it can be better because an interface specification cannot test
certain properties of a program.  For example, the *note list.append():
6d0. method is expected to add new elements to the end of some internal
list; an interface specification cannot test that your ‘list.append()’
implementation will actually do this correctly, but it’s trivial to
check this property in a test suite.

Writing test suites is very helpful, and you might want to design your
code to make it easily tested.  One increasingly popular technique,
test-driven development, calls for writing parts of the test suite
first, before you write any of the actual code.  Of course Python allows
you to be sloppy and not write test cases at all.


File: python.info,  Node: Why is there no goto?,  Next: Why can’t raw strings r-strings end with a backslash?,  Prev: How do you specify and enforce an interface spec in Python?,  Up: Design and History FAQ

10.3.23 Why is there no goto?
-----------------------------

In the 1970s people realized that unrestricted goto could lead to messy
“spaghetti” code that was hard to understand and revise.  In a
high-level language, it is also unneeded as long as there are ways to
branch (in Python, with *note if: 2f3. statements and *note or: 2f6,
*note and: 2f1, and ‘if’/*note else: 18c. expressions) and loop (with
*note while: 1d9a. and *note for: 2f2. statements, possibly containing
*note continue: 9d4. and *note break: abe.).

One can also use exceptions to provide a “structured goto” that works
even across function calls.  Many feel that exceptions can conveniently
emulate all reasonable uses of the ‘go’ or ‘goto’ constructs of C,
Fortran, and other languages.  For example:

     class label(Exception): pass  # declare a label

     try:
         ...
         if condition: raise label()  # goto label
         ...
     except label:  # where to goto
         pass
     ...

This doesn’t allow you to jump into the middle of a loop, but that’s
usually considered an abuse of ‘goto’ anyway.  Use sparingly.


File: python.info,  Node: Why can’t raw strings r-strings end with a backslash?,  Next: Why doesn’t Python have a “with” statement for attribute assignments?,  Prev: Why is there no goto?,  Up: Design and History FAQ

10.3.24 Why can’t raw strings (r-strings) end with a backslash?
---------------------------------------------------------------

More precisely, they can’t end with an odd number of backslashes: the
unpaired backslash at the end escapes the closing quote character,
leaving an unterminated string.

Raw strings were designed to ease creating input for processors (chiefly
regular expression engines) that want to do their own backslash escape
processing.  Such processors consider an unmatched trailing backslash to
be an error anyway, so raw strings disallow that.  In return, they allow
you to pass on the string quote character by escaping it with a
backslash.  These rules work well when r-strings are used for their
intended purpose.

If you’re trying to build Windows pathnames, note that all Windows
system calls accept forward slashes too:

     f = open("/mydir/file.txt")  # works fine!

If you’re trying to build a pathname for a DOS command, try e.g.  one of

     dir = r"\this\is\my\dos\dir" "\\"
     dir = r"\this\is\my\dos\dir\ "[:-1]
     dir = "\\this\\is\\my\\dos\\dir\\"


File: python.info,  Node: Why doesn’t Python have a “with” statement for attribute assignments?,  Next: Why don’t generators support the with statement?,  Prev: Why can’t raw strings r-strings end with a backslash?,  Up: Design and History FAQ

10.3.25 Why doesn’t Python have a “with” statement for attribute assignments?
-----------------------------------------------------------------------------

Python has a *note with: 5d5. statement that wraps the execution of a
block, calling code on the entrance and exit from the block.  Some
languages have a construct that looks like this:

     with obj:
         a = 1               # equivalent to obj.a = 1
         total = total + 1   # obj.total = obj.total + 1

In Python, such a construct would be ambiguous.

Other languages, such as Object Pascal, Delphi, and C++, use static
types, so it’s possible to know, in an unambiguous way, what member is
being assigned to.  This is the main point of static typing – the
compiler 'always' knows the scope of every variable at compile time.

Python uses dynamic types.  It is impossible to know in advance which
attribute will be referenced at runtime.  Member attributes may be added
or removed from objects on the fly.  This makes it impossible to know,
from a simple reading, what attribute is being referenced: a local one,
a global one, or a member attribute?

For instance, take the following incomplete snippet:

     def foo(a):
         with a:
             print(x)

The snippet assumes that ‘a’ must have a member attribute called ‘x’.
However, there is nothing in Python that tells the interpreter this.
What should happen if ‘a’ is, let us say, an integer?  If there is a
global variable named ‘x’, will it be used inside the *note with: 5d5.
block?  As you see, the dynamic nature of Python makes such choices much
harder.

The primary benefit of *note with: 5d5. and similar language features
(reduction of code volume) can, however, easily be achieved in Python by
assignment.  Instead of:

     function(args).mydict[index][index].a = 21
     function(args).mydict[index][index].b = 42
     function(args).mydict[index][index].c = 63

write this:

     ref = function(args).mydict[index][index]
     ref.a = 21
     ref.b = 42
     ref.c = 63

This also has the side-effect of increasing execution speed because name
bindings are resolved at run-time in Python, and the second version only
needs to perform the resolution once.

Similar proposals that would introduce syntax to further reduce code
volume, such as using a ‘leading dot’, have been rejected in favour of
explicitness (see
‘https://mail.python.org/pipermail/python-ideas/2016-May/040070.html’).


File: python.info,  Node: Why don’t generators support the with statement?,  Next: Why are colons required for the if/while/def/class statements?,  Prev: Why doesn’t Python have a “with” statement for attribute assignments?,  Up: Design and History FAQ

10.3.26 Why don’t generators support the with statement?
--------------------------------------------------------

For technical reasons, a generator used directly as a context manager
would not work correctly.  When, as is most common, a generator is used
as an iterator run to completion, no closing is needed.  When it is,
wrap it as *note contextlib.closing(generator): 13d6. in the *note with:
5d5. statement.


File: python.info,  Node: Why are colons required for the if/while/def/class statements?,  Next: Why does Python allow commas at the end of lists and tuples?,  Prev: Why don’t generators support the with statement?,  Up: Design and History FAQ

10.3.27 Why are colons required for the if/while/def/class statements?
----------------------------------------------------------------------

The colon is required primarily to enhance readability (one of the
results of the experimental ABC language).  Consider this:

     if a == b
         print(a)

versus

     if a == b:
         print(a)

Notice how the second one is slightly easier to read.  Notice further
how a colon sets off the example in this FAQ answer; it’s a standard
usage in English.

Another minor reason is that the colon makes it easier for editors with
syntax highlighting; they can look for colons to decide when indentation
needs to be increased instead of having to do a more elaborate parsing
of the program text.


File: python.info,  Node: Why does Python allow commas at the end of lists and tuples?,  Prev: Why are colons required for the if/while/def/class statements?,  Up: Design and History FAQ

10.3.28 Why does Python allow commas at the end of lists and tuples?
--------------------------------------------------------------------

Python lets you add a trailing comma at the end of lists, tuples, and
dictionaries:

     [1, 2, 3,]
     ('a', 'b', 'c',)
     d = {
         "A": [1, 5],
         "B": [6, 7],  # last trailing comma is optional but good style
     }

There are several reasons to allow this.

When you have a literal value for a list, tuple, or dictionary spread
across multiple lines, it’s easier to add more elements because you
don’t have to remember to add a comma to the previous line.  The lines
can also be reordered without creating a syntax error.

Accidentally omitting the comma can lead to errors that are hard to
diagnose.  For example:

     x = [
       "fee",
       "fie"
       "foo",
       "fum"
     ]

This list looks like it has four elements, but it actually contains
three: “fee”, “fiefoo” and “fum”.  Always adding the comma avoids this
source of error.

Allowing the trailing comma may also make programmatic code generation
easier.


File: python.info,  Node: Library and Extension FAQ,  Next: Extending/Embedding FAQ,  Prev: Design and History FAQ,  Up: Python Frequently Asked Questions

10.4 Library and Extension FAQ
==============================

* Menu:

* General Library Questions::
* Common tasks::
* Threads::
* Input and Output: Input and Output<2>.
* Network/Internet Programming::
* Databases::
* Mathematics and Numerics::


File: python.info,  Node: General Library Questions,  Next: Common tasks,  Up: Library and Extension FAQ

10.4.1 General Library Questions
--------------------------------

* Menu:

* How do I find a module or application to perform task X?::
* Where is the math.py (socket.py, regex.py, etc.) source file?: Where is the math py socket py regex py etc source file?.
* How do I make a Python script executable on Unix?::
* Is there a curses/termcap package for Python?::
* Is there an equivalent to C’s onexit() in Python?: Is there an equivalent to C’s onexit in Python?.
* Why don’t my signal handlers work?::


File: python.info,  Node: How do I find a module or application to perform task X?,  Next: Where is the math py socket py regex py etc source file?,  Up: General Library Questions

10.4.1.1 How do I find a module or application to perform task X?
.................................................................

Check *note the Library Reference: 144. to see if there’s a relevant
standard library module.  (Eventually you’ll learn what’s in the
standard library and will be able to skip this step.)

For third-party packages, search the Python Package Index(1) or try
Google(2) or another web search engine.  Searching for “Python” plus a
keyword or two for your topic of interest will usually find something
helpful.

   ---------- Footnotes ----------

   (1) https://pypi.org

   (2) https://www.google.com


File: python.info,  Node: Where is the math py socket py regex py etc source file?,  Next: How do I make a Python script executable on Unix?,  Prev: How do I find a module or application to perform task X?,  Up: General Library Questions

10.4.1.2 Where is the math.py (socket.py, regex.py, etc.) source file?
......................................................................

If you can’t find a source file for a module it may be a built-in or
dynamically loaded module implemented in C, C++ or other compiled
language.  In this case you may not have the source file or it may be
something like ‘mathmodule.c’, somewhere in a C source directory (not on
the Python Path).

There are (at least) three kinds of modules in Python:

  1. modules written in Python (.py);

  2. modules written in C and dynamically loaded (.dll, .pyd, .so, .sl,
     etc);

  3. modules written in C and linked with the interpreter; to get a list
     of these, type:

          import sys
          print(sys.builtin_module_names)


File: python.info,  Node: How do I make a Python script executable on Unix?,  Next: Is there a curses/termcap package for Python?,  Prev: Where is the math py socket py regex py etc source file?,  Up: General Library Questions

10.4.1.3 How do I make a Python script executable on Unix?
..........................................................

You need to do two things: the script file’s mode must be executable and
the first line must begin with ‘#!’ followed by the path of the Python
interpreter.

The first is done by executing ‘chmod +x scriptfile’ or perhaps ‘chmod
755 scriptfile’.

The second can be done in a number of ways.  The most straightforward
way is to write

     #!/usr/local/bin/python

as the very first line of your file, using the pathname for where the
Python interpreter is installed on your platform.

If you would like the script to be independent of where the Python
interpreter lives, you can use the ‘env’ program.  Almost all Unix
variants support the following, assuming the Python interpreter is in a
directory on the user’s ‘PATH’:

     #!/usr/bin/env python

'Don’t' do this for CGI scripts.  The ‘PATH’ variable for CGI scripts is
often very minimal, so you need to use the actual absolute pathname of
the interpreter.

Occasionally, a user’s environment is so full that the ‘/usr/bin/env’
program fails; or there’s no env program at all.  In that case, you can
try the following hack (due to Alex Rezinsky):

     #! /bin/sh
     """:"
     exec python $0 ${1+"$@"}
     """

The minor disadvantage is that this defines the script’s __doc__ string.
However, you can fix that by adding

     __doc__ = """...Whatever..."""


File: python.info,  Node: Is there a curses/termcap package for Python?,  Next: Is there an equivalent to C’s onexit in Python?,  Prev: How do I make a Python script executable on Unix?,  Up: General Library Questions

10.4.1.4 Is there a curses/termcap package for Python?
......................................................

For Unix variants: The standard Python source distribution comes with a
curses module in the Modules(1) subdirectory, though it’s not compiled
by default.  (Note that this is not available in the Windows
distribution – there is no curses module for Windows.)

The *note curses: 2b. module supports basic curses features as well as
many additional functions from ncurses and SYSV curses such as colour,
alternative character set support, pads, and mouse support.  This means
the module isn’t compatible with operating systems that only have BSD
curses, but there don’t seem to be any currently maintained OSes that
fall into this category.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Modules


File: python.info,  Node: Is there an equivalent to C’s onexit in Python?,  Next: Why don’t my signal handlers work?,  Prev: Is there a curses/termcap package for Python?,  Up: General Library Questions

10.4.1.5 Is there an equivalent to C’s onexit() in Python?
..........................................................

The *note atexit: c. module provides a register function that is similar
to C’s ‘onexit()’.


File: python.info,  Node: Why don’t my signal handlers work?,  Prev: Is there an equivalent to C’s onexit in Python?,  Up: General Library Questions

10.4.1.6 Why don’t my signal handlers work?
...........................................

The most common problem is that the signal handler is declared with the
wrong argument list.  It is called as

     handler(signum, frame)

so it should be declared with two parameters:

     def handler(signum, frame):
         ...


File: python.info,  Node: Common tasks,  Next: Threads,  Prev: General Library Questions,  Up: Library and Extension FAQ

10.4.2 Common tasks
-------------------

* Menu:

* How do I test a Python program or component?::
* How do I create documentation from doc strings?::
* How do I get a single keypress at a time?::


File: python.info,  Node: How do I test a Python program or component?,  Next: How do I create documentation from doc strings?,  Up: Common tasks

10.4.2.1 How do I test a Python program or component?
.....................................................

Python comes with two testing frameworks.  The *note doctest: 3a. module
finds examples in the docstrings for a module and runs them, comparing
the output with the expected output given in the docstring.

The *note unittest: 106. module is a fancier testing framework modelled
on Java and Smalltalk testing frameworks.

To make testing easier, you should use good modular design in your
program.  Your program should have almost all functionality encapsulated
in either functions or class methods – and this sometimes has the
surprising and delightful effect of making the program run faster
(because local variable accesses are faster than global accesses).
Furthermore the program should avoid depending on mutating global
variables, since this makes testing much more difficult to do.

The “global main logic” of your program may be as simple as

     if __name__ == "__main__":
         main_logic()

at the bottom of the main module of your program.

Once your program is organized as a tractable collection of function and
class behaviours, you should write test functions that exercise the
behaviours.  A test suite that automates a sequence of tests can be
associated with each module.  This sounds like a lot of work, but since
Python is so terse and flexible it’s surprisingly easy.  You can make
coding much more pleasant and fun by writing your test functions in
parallel with the “production code”, since this makes it easy to find
bugs and even design flaws earlier.

“Support modules” that are not intended to be the main module of a
program may include a self-test of the module.

     if __name__ == "__main__":
         self_test()

Even programs that interact with complex external interfaces may be
tested when the external interfaces are unavailable by using “fake”
interfaces implemented in Python.


File: python.info,  Node: How do I create documentation from doc strings?,  Next: How do I get a single keypress at a time?,  Prev: How do I test a Python program or component?,  Up: Common tasks

10.4.2.2 How do I create documentation from doc strings?
........................................................

The *note pydoc: b5. module can create HTML from the doc strings in your
Python source code.  An alternative for creating API documentation
purely from docstrings is epydoc(1).  Sphinx(2) can also include
docstring content.

   ---------- Footnotes ----------

   (1) https://epydoc.sourceforge.net/

   (2) https://www.sphinx-doc.org


File: python.info,  Node: How do I get a single keypress at a time?,  Prev: How do I create documentation from doc strings?,  Up: Common tasks

10.4.2.3 How do I get a single keypress at a time?
..................................................

For Unix variants there are several solutions.  It’s straightforward to
do this using curses, but curses is a fairly large module to learn.


File: python.info,  Node: Threads,  Next: Input and Output<2>,  Prev: Common tasks,  Up: Library and Extension FAQ

10.4.3 Threads
--------------

* Menu:

* How do I program using threads?::
* None of my threads seem to run; why?: None of my threads seem to run why?.
* How do I parcel out work among a bunch of worker threads?::
* What kinds of global value mutation are thread-safe?::
* Can’t we get rid of the Global Interpreter Lock?::


File: python.info,  Node: How do I program using threads?,  Next: None of my threads seem to run why?,  Up: Threads

10.4.3.1 How do I program using threads?
........................................

Be sure to use the *note threading: ed. module and not the *note
_thread: 2. module.  The ‘threading’ module builds convenient
abstractions on top of the low-level primitives provided by the
‘_thread’ module.


File: python.info,  Node: None of my threads seem to run why?,  Next: How do I parcel out work among a bunch of worker threads?,  Prev: How do I program using threads?,  Up: Threads

10.4.3.2 None of my threads seem to run: why?
.............................................

As soon as the main thread exits, all threads are killed.  Your main
thread is running too quickly, giving the threads no time to do any
work.

A simple fix is to add a sleep to the end of the program that’s long
enough for all the threads to finish:

     import threading, time

     def thread_task(name, n):
         for i in range(n):
             print(name, i)

     for i in range(10):
         T = threading.Thread(target=thread_task, args=(str(i), i))
         T.start()

     time.sleep(10)  # <---------------------------!

But now (on many platforms) the threads don’t run in parallel, but
appear to run sequentially, one at a time!  The reason is that the OS
thread scheduler doesn’t start a new thread until the previous thread is
blocked.

A simple fix is to add a tiny sleep to the start of the run function:

     def thread_task(name, n):
         time.sleep(0.001)  # <--------------------!
         for i in range(n):
             print(name, i)

     for i in range(10):
         T = threading.Thread(target=thread_task, args=(str(i), i))
         T.start()

     time.sleep(10)

Instead of trying to guess a good delay value for *note time.sleep():
6a0, it’s better to use some kind of semaphore mechanism.  One idea is
to use the *note queue: b6. module to create a queue object, let each
thread append a token to the queue when it finishes, and let the main
thread read as many tokens from the queue as there are threads.


File: python.info,  Node: How do I parcel out work among a bunch of worker threads?,  Next: What kinds of global value mutation are thread-safe?,  Prev: None of my threads seem to run why?,  Up: Threads

10.4.3.3 How do I parcel out work among a bunch of worker threads?
..................................................................

The easiest way is to use the *note concurrent.futures: 21. module,
especially the *note ThreadPoolExecutor: 745. class.

Or, if you want fine control over the dispatching algorithm, you can
write your own logic manually.  Use the *note queue: b6. module to
create a queue containing a list of jobs.  The *note Queue: 13e1. class
maintains a list of objects and has a ‘.put(obj)’ method that adds items
to the queue and a ‘.get()’ method to return them.  The class will take
care of the locking necessary to ensure that each job is handed out
exactly once.

Here’s a trivial example:

     import threading, queue, time

     # The worker thread gets jobs off the queue.  When the queue is empty, it
     # assumes there will be no more work and exits.
     # (Realistically workers will run until terminated.)
     def worker():
         print('Running worker')
         time.sleep(0.1)
         while True:
             try:
                 arg = q.get(block=False)
             except queue.Empty:
                 print('Worker', threading.current_thread(), end=' ')
                 print('queue empty')
                 break
             else:
                 print('Worker', threading.current_thread(), end=' ')
                 print('running with argument', arg)
                 time.sleep(0.5)

     # Create queue
     q = queue.Queue()

     # Start a pool of 5 workers
     for i in range(5):
         t = threading.Thread(target=worker, name='worker %i' % (i+1))
         t.start()

     # Begin adding work to the queue
     for i in range(50):
         q.put(i)

     # Give threads time to run
     print('Main thread sleeping')
     time.sleep(5)

When run, this will produce the following output:

     Running worker
     Running worker
     Running worker
     Running worker
     Running worker
     Main thread sleeping
     Worker <Thread(worker 1, started 130283832797456)> running with argument 0
     Worker <Thread(worker 2, started 130283824404752)> running with argument 1
     Worker <Thread(worker 3, started 130283816012048)> running with argument 2
     Worker <Thread(worker 4, started 130283807619344)> running with argument 3
     Worker <Thread(worker 5, started 130283799226640)> running with argument 4
     Worker <Thread(worker 1, started 130283832797456)> running with argument 5
     ...

Consult the module’s documentation for more details; the *note Queue:
13e1. class provides a featureful interface.


File: python.info,  Node: What kinds of global value mutation are thread-safe?,  Next: Can’t we get rid of the Global Interpreter Lock?,  Prev: How do I parcel out work among a bunch of worker threads?,  Up: Threads

10.4.3.4 What kinds of global value mutation are thread-safe?
.............................................................

A *note global interpreter lock: 148. (GIL) is used internally to ensure
that only one thread runs in the Python VM at a time.  In general,
Python offers to switch among threads only between bytecode
instructions; how frequently it switches can be set via *note
sys.setswitchinterval(): 954.  Each bytecode instruction and therefore
all the C implementation code reached from each instruction is therefore
atomic from the point of view of a Python program.

In theory, this means an exact accounting requires an exact
understanding of the PVM bytecode implementation.  In practice, it means
that operations on shared variables of built-in data types (ints, lists,
dicts, etc) that “look atomic” really are.

For example, the following operations are all atomic (L, L1, L2 are
lists, D, D1, D2 are dicts, x, y are objects, i, j are ints):

     L.append(x)
     L1.extend(L2)
     x = L[i]
     x = L.pop()
     L1[i:j] = L2
     L.sort()
     x = y
     x.field = y
     D[x] = y
     D1.update(D2)
     D.keys()

These aren’t:

     i = i+1
     L.append(L[-1])
     L[i] = L[j]
     D[x] = D[x] + 1

Operations that replace other objects may invoke those other objects’
*note __del__(): 1038. method when their reference count reaches zero,
and that can affect things.  This is especially true for the mass
updates to dictionaries and lists.  When in doubt, use a mutex!


File: python.info,  Node: Can’t we get rid of the Global Interpreter Lock?,  Prev: What kinds of global value mutation are thread-safe?,  Up: Threads

10.4.3.5 Can’t we get rid of the Global Interpreter Lock?
.........................................................

The *note global interpreter lock: 148. (GIL) is often seen as a
hindrance to Python’s deployment on high-end multiprocessor server
machines, because a multi-threaded Python program effectively only uses
one CPU, due to the insistence that (almost) all Python code can only
run while the GIL is held.

With the approval of PEP 703(1) work is now underway to remove the GIL
from the CPython implementation of Python.  Initially it will be
implemented as an optional compiler flag when building the interpreter,
and so separate builds will be available with and without the GIL.
Long-term, the hope is to settle on a single build, once the performance
implications of removing the GIL are fully understood.  Python 3.13 is
likely to be the first release containing this work, although it may not
be completely functional in this release.

The current work to remove the GIL is based on a fork of Python 3.9 with
the GIL removed(2) by Sam Gross.  Prior to that, in the days of Python
1.5, Greg Stein actually implemented a comprehensive patch set (the
“free threading” patches) that removed the GIL and replaced it with
fine-grained locking.  Adam Olsen did a similar experiment in his
python-safethread(3) project.  Unfortunately, both of these earlier
experiments exhibited a sharp drop in single-thread performance (at
least 30% slower), due to the amount of fine-grained locking necessary
to compensate for the removal of the GIL. The Python 3.9 fork is the
first attempt at removing the GIL with an acceptable performance impact.

The presence of the GIL in current Python releases doesn’t mean that you
can’t make good use of Python on multi-CPU machines!  You just have to
be creative with dividing the work up between multiple 'processes'
rather than multiple 'threads'.  The *note ProcessPoolExecutor: 8f7.
class in the new *note concurrent.futures: 21. module provides an easy
way of doing so; the *note multiprocessing: 94. module provides a
lower-level API in case you want more control over dispatching of tasks.

Judicious use of C extensions will also help; if you use a C extension
to perform a time-consuming task, the extension can release the GIL
while the thread of execution is in the C code and allow other threads
to get some work done.  Some standard library modules such as *note
zlib: 133. and *note hashlib: 68. already do this.

An alternative approach to reducing the impact of the GIL is to make the
GIL a per-interpreter-state lock rather than truly global.  This was
*note first implemented in Python 3.12: 43f. and is available in the C
API. A Python interface to it is expected in Python 3.13.  The main
limitation to it at the moment is likely to be 3rd party extension
modules, since these must be written with multiple interpreters in mind
in order to be usable, so many older extension modules will not be
usable.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0703/

   (2) https://github.com/colesbury/nogil

   (3) https://code.google.com/archive/p/python-safethread


File: python.info,  Node: Input and Output<2>,  Next: Network/Internet Programming,  Prev: Threads,  Up: Library and Extension FAQ

10.4.4 Input and Output
-----------------------

* Menu:

* How do I delete a file? (And other file questions…): How do I delete a file? And other file questions….
* How do I copy a file?::
* How do I read (or write) binary data?: How do I read or write binary data?.
* I can’t seem to use os.read() on a pipe created with os.popen(); why?: I can’t seem to use os read on a pipe created with os popen ; why?.
* How do I access the serial (RS232) port?: How do I access the serial RS232 port?.
* Why doesn’t closing sys.stdout (stdin, stderr) really close it?: Why doesn’t closing sys stdout stdin stderr really close it?.


File: python.info,  Node: How do I delete a file? And other file questions…,  Next: How do I copy a file?,  Up: Input and Output<2>

10.4.4.1 How do I delete a file? (And other file questions…)
............................................................

Use ‘os.remove(filename)’ or ‘os.unlink(filename)’; for documentation,
see the *note os: a1. module.  The two functions are identical; *note
unlink(): 1139. is simply the name of the Unix system call for this
function.

To remove a directory, use *note os.rmdir(): 1137.; use *note
os.mkdir(): 21d. to create one.  ‘os.makedirs(path)’ will create any
intermediate directories in ‘path’ that don’t exist.
‘os.removedirs(path)’ will remove intermediate directories as long as
they’re empty; if you want to delete an entire directory tree and its
contents, use *note shutil.rmtree(): 301.

To rename a file, use ‘os.rename(old_path, new_path)’.

To truncate a file, open it using ‘f = open(filename, "rb+")’, and use
‘f.truncate(offset)’; offset defaults to the current seek position.
There’s also ‘os.ftruncate(fd, offset)’ for files opened with *note
os.open(): dc0, where 'fd' is the file descriptor (a small integer).

The *note shutil: c5. module also contains a number of functions to work
on files including *note copyfile(): a67, *note copytree(): a36, and
*note rmtree(): 301.


File: python.info,  Node: How do I copy a file?,  Next: How do I read or write binary data?,  Prev: How do I delete a file? And other file questions…,  Up: Input and Output<2>

10.4.4.2 How do I copy a file?
..............................

The *note shutil: c5. module contains a *note copyfile(): a67. function.
Note that on Windows NTFS volumes, it does not copy alternate data
streams(1) nor resource forks(2) on macOS HFS+ volumes, though both are
now rarely used.  It also doesn’t copy file permissions and metadata,
though using *note shutil.copy2(): a69. instead will preserve most
(though not all) of it.

   ---------- Footnotes ----------

   (1) https://en.wikipedia.org/wiki/NTFS#Alternate_data_stream_(ADS)

   (2) https://en.wikipedia.org/wiki/Resource_fork


File: python.info,  Node: How do I read or write binary data?,  Next: I can’t seem to use os read on a pipe created with os popen ; why?,  Prev: How do I copy a file?,  Up: Input and Output<2>

10.4.4.3 How do I read (or write) binary data?
..............................................

To read or write complex binary data formats, it’s best to use the *note
struct: d5. module.  It allows you to take a string containing binary
data (usually numbers) and convert it to Python objects; and vice versa.

For example, the following code reads two 2-byte integers and one 4-byte
integer in big-endian format from a file:

     import struct

     with open(filename, "rb") as f:
         s = f.read(8)
         x, y, z = struct.unpack(">hhl", s)

The ‘>’ in the format string forces big-endian data; the letter ‘h’
reads one “short integer” (2 bytes), and ‘l’ reads one “long integer” (4
bytes) from the string.

For data that is more regular (e.g.  a homogeneous list of ints or
floats), you can also use the *note array: 7. module.

     Note: To read and write binary data, it is mandatory to open the
     file in binary mode (here, passing ‘"rb"’ to *note open(): 51f.).
     If you use ‘"r"’ instead (the default), the file will be open in
     text mode and ‘f.read()’ will return *note str: 44f. objects rather
     than *note bytes: 1c2. objects.


File: python.info,  Node: I can’t seem to use os read on a pipe created with os popen ; why?,  Next: How do I access the serial RS232 port?,  Prev: How do I read or write binary data?,  Up: Input and Output<2>

10.4.4.4 I can’t seem to use os.read() on a pipe created with os.popen(); why?
..............................................................................

*note os.read(): dc3. is a low-level function which takes a file
descriptor, a small integer representing the opened file.  *note
os.popen(): a96. creates a high-level file object, the same type
returned by the built-in *note open(): 51f. function.  Thus, to read 'n'
bytes from a pipe 'p' created with ‘os.popen()’, you need to use
‘p.read(n)’.


File: python.info,  Node: How do I access the serial RS232 port?,  Next: Why doesn’t closing sys stdout stdin stderr really close it?,  Prev: I can’t seem to use os read on a pipe created with os popen ; why?,  Up: Input and Output<2>

10.4.4.5 How do I access the serial (RS232) port?
.................................................

For Win32, OSX, Linux, BSD, Jython, IronPython:

     pyserial(1)

For Unix, see a Usenet post by Mitch Chapman:

     ‘https://groups.google.com/groups?selm=34A04430.CF9@ohioee.com’

   ---------- Footnotes ----------

   (1) https://pypi.org/project/pyserial/


File: python.info,  Node: Why doesn’t closing sys stdout stdin stderr really close it?,  Prev: How do I access the serial RS232 port?,  Up: Input and Output<2>

10.4.4.6 Why doesn’t closing sys.stdout (stdin, stderr) really close it?
........................................................................

Python *note file objects: 1208. are a high-level layer of abstraction
on low-level C file descriptors.

For most file objects you create in Python via the built-in *note
open(): 51f. function, ‘f.close()’ marks the Python file object as being
closed from Python’s point of view, and also arranges to close the
underlying C file descriptor.  This also happens automatically in ‘f’’s
destructor, when ‘f’ becomes garbage.

But stdin, stdout and stderr are treated specially by Python, because of
the special status also given to them by C. Running ‘sys.stdout.close()’
marks the Python-level file object as being closed, but does 'not' close
the associated C file descriptor.

To close the underlying C file descriptor for one of these three, you
should first be sure that’s what you really want to do (e.g., you may
confuse extension modules trying to do I/O). If it is, use *note
os.close(): b90.:

     os.close(stdin.fileno())
     os.close(stdout.fileno())
     os.close(stderr.fileno())

Or you can use the numeric constants 0, 1 and 2, respectively.


File: python.info,  Node: Network/Internet Programming,  Next: Databases,  Prev: Input and Output<2>,  Up: Library and Extension FAQ

10.4.5 Network/Internet Programming
-----------------------------------

* Menu:

* What WWW tools are there for Python?::
* What module should I use to help with generating HTML?::
* How do I send mail from a Python script?::
* How do I avoid blocking in the connect() method of a socket?: How do I avoid blocking in the connect method of a socket?.


File: python.info,  Node: What WWW tools are there for Python?,  Next: What module should I use to help with generating HTML?,  Up: Network/Internet Programming

10.4.5.1 What WWW tools are there for Python?
.............................................

See the chapters titled *note Internet Protocols and Support: 3b8b. and
*note Internet Data Handling: 3781. in the Library Reference Manual.
Python has many modules that will help you build server-side and
client-side web systems.

A summary of available frameworks is maintained by Paul Boddie at
‘https://wiki.python.org/moin/WebProgramming’.


File: python.info,  Node: What module should I use to help with generating HTML?,  Next: How do I send mail from a Python script?,  Prev: What WWW tools are there for Python?,  Up: Network/Internet Programming

10.4.5.2 What module should I use to help with generating HTML?
...............................................................

You can find a collection of useful links on the Web Programming wiki
page(1).

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/WebProgramming


File: python.info,  Node: How do I send mail from a Python script?,  Next: How do I avoid blocking in the connect method of a socket?,  Prev: What module should I use to help with generating HTML?,  Up: Network/Internet Programming

10.4.5.3 How do I send mail from a Python script?
.................................................

Use the standard library module *note smtplib: ca.

Here’s a very simple interactive mail sender that uses it.  This method
will work on any host that supports an SMTP listener.

     import sys, smtplib

     fromaddr = input("From: ")
     toaddrs  = input("To: ").split(',')
     print("Enter message, end with ^D:")
     msg = ''
     while True:
         line = sys.stdin.readline()
         if not line:
             break
         msg += line

     # The actual mail send
     server = smtplib.SMTP('localhost')
     server.sendmail(fromaddr, toaddrs, msg)
     server.quit()

A Unix-only alternative uses sendmail.  The location of the sendmail
program varies between systems; sometimes it is ‘/usr/lib/sendmail’,
sometimes ‘/usr/sbin/sendmail’.  The sendmail manual page will help you
out.  Here’s some sample code:

     import os

     SENDMAIL = "/usr/sbin/sendmail"  # sendmail location
     p = os.popen("%s -t -i" % SENDMAIL, "w")
     p.write("To: receiver@example.com\n")
     p.write("Subject: test\n")
     p.write("\n")  # blank line separating headers from body
     p.write("Some text\n")
     p.write("some more text\n")
     sts = p.close()
     if sts != 0:
         print("Sendmail exit status", sts)


File: python.info,  Node: How do I avoid blocking in the connect method of a socket?,  Prev: How do I send mail from a Python script?,  Up: Network/Internet Programming

10.4.5.4 How do I avoid blocking in the connect() method of a socket?
.....................................................................

The *note select: c1. module is commonly used to help with asynchronous
I/O on sockets.

To prevent the TCP connect from blocking, you can set the socket to
non-blocking mode.  Then when you do the *note connect(): dd1, you will
either connect immediately (unlikely) or get an exception that contains
the error number as ‘.errno’.  ‘errno.EINPROGRESS’ indicates that the
connection is in progress, but hasn’t finished yet.  Different OSes will
return different values, so you’re going to have to check what’s
returned on your system.

You can use the *note connect_ex(): 1589. method to avoid creating an
exception.  It will just return the errno value.  To poll, you can call
‘connect_ex()’ again later – ‘0’ or ‘errno.EISCONN’ indicate that you’re
connected – or you can pass this socket to *note select.select(): dce.
to check if it’s writable.

     Note: The *note asyncio: a. module provides a general purpose
     single-threaded and concurrent asynchronous library, which can be
     used for writing non-blocking network code.  The third-party
     Twisted(1) library is a popular and feature-rich alternative.

   ---------- Footnotes ----------

   (1) https://twisted.org/


File: python.info,  Node: Databases,  Next: Mathematics and Numerics,  Prev: Network/Internet Programming,  Up: Library and Extension FAQ

10.4.6 Databases
----------------

* Menu:

* Are there any interfaces to database packages in Python?::
* How do you implement persistent objects in Python?::


File: python.info,  Node: Are there any interfaces to database packages in Python?,  Next: How do you implement persistent objects in Python?,  Up: Databases

10.4.6.1 Are there any interfaces to database packages in Python?
.................................................................

Yes.

Interfaces to disk-based hashes such as *note DBM: 34. and *note GDBM:
33. are also included with standard Python.  There is also the *note
sqlite3: cf. module, which provides a lightweight disk-based relational
database.

Support for most relational databases is available.  See the
DatabaseProgramming wiki page(1) for details.

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/DatabaseProgramming


File: python.info,  Node: How do you implement persistent objects in Python?,  Prev: Are there any interfaces to database packages in Python?,  Up: Databases

10.4.6.2 How do you implement persistent objects in Python?
...........................................................

The *note pickle: a6. library module solves this in a very general way
(though you still can’t store things like open files, sockets or
windows), and the *note shelve: c3. library module uses pickle and
(g)dbm to create persistent mappings containing arbitrary Python
objects.


File: python.info,  Node: Mathematics and Numerics,  Prev: Databases,  Up: Library and Extension FAQ

10.4.7 Mathematics and Numerics
-------------------------------

* Menu:

* How do I generate random numbers in Python?::


File: python.info,  Node: How do I generate random numbers in Python?,  Up: Mathematics and Numerics

10.4.7.1 How do I generate random numbers in Python?
....................................................

The standard module *note random: b8. implements a random number
generator.  Usage is simple:

     import random
     random.random()

This returns a random floating-point number in the range [0, 1).

There are also many other specialized generators in this module, such
as:

   * ‘randrange(a, b)’ chooses an integer in the range [a, b).

   * ‘uniform(a, b)’ chooses a floating-point number in the range [a,
     b).

   * ‘normalvariate(mean, sdev)’ samples the normal (Gaussian)
     distribution.

Some higher-level functions operate on sequences directly, such as:

   * ‘choice(S)’ chooses a random element from a given sequence.

   * ‘shuffle(L)’ shuffles a list in-place, i.e.  permutes it randomly.

There’s also a ‘Random’ class you can instantiate to create independent
multiple random number generators.


File: python.info,  Node: Extending/Embedding FAQ,  Next: Python on Windows FAQ,  Prev: Library and Extension FAQ,  Up: Python Frequently Asked Questions

10.5 Extending/Embedding FAQ
============================

* Menu:

* Can I create my own functions in C?::
* Can I create my own functions in C++?::
* Writing C is hard; are there any alternatives?::
* How can I execute arbitrary Python statements from C?::
* How can I evaluate an arbitrary Python expression from C?::
* How do I extract C values from a Python object?::
* How do I use Py_BuildValue() to create a tuple of arbitrary length?: How do I use Py_BuildValue to create a tuple of arbitrary length?.
* How do I call an object’s method from C?::
* How do I catch the output from PyErr_Print() (or anything that prints to stdout/stderr)?: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?.
* How do I access a module written in Python from C?::
* How do I interface to C++ objects from Python?::
* I added a module using the Setup file and the make fails; why?::
* How do I debug an extension?::
* I want to compile a Python module on my Linux system, but some files are missing. Why?: I want to compile a Python module on my Linux system but some files are missing Why?.
* How do I tell “incomplete input” from “invalid input”?::
* How do I find undefined g++ symbols __builtin_new or __pure_virtual?::
* Can I create an object class with some methods implemented in C and others in Python (e.g. through inheritance)?: Can I create an object class with some methods implemented in C and others in Python e g through inheritance ?.


File: python.info,  Node: Can I create my own functions in C?,  Next: Can I create my own functions in C++?,  Up: Extending/Embedding FAQ

10.5.1 Can I create my own functions in C?
------------------------------------------

Yes, you can create built-in modules containing functions, variables,
exceptions and even new types in C. This is explained in the document
*note Extending and Embedding the Python Interpreter: 1d6e.

Most intermediate or advanced Python books will also cover this topic.


File: python.info,  Node: Can I create my own functions in C++?,  Next: Writing C is hard; are there any alternatives?,  Prev: Can I create my own functions in C?,  Up: Extending/Embedding FAQ

10.5.2 Can I create my own functions in C++?
--------------------------------------------

Yes, using the C compatibility features found in C++.  Place ‘extern "C"
{ ... }’ around the Python include files and put ‘extern "C"’ before
each function that is going to be called by the Python interpreter.
Global or static C++ objects with constructors are probably not a good
idea.


File: python.info,  Node: Writing C is hard; are there any alternatives?,  Next: How can I execute arbitrary Python statements from C?,  Prev: Can I create my own functions in C++?,  Up: Extending/Embedding FAQ

10.5.3 Writing C is hard; are there any alternatives?
-----------------------------------------------------

There are a number of alternatives to writing your own C extensions,
depending on what you’re trying to do.  *note Recommended third party
tools: 4b58. offer both simpler and more sophisticated approaches to
creating C and C++ extensions for Python.


File: python.info,  Node: How can I execute arbitrary Python statements from C?,  Next: How can I evaluate an arbitrary Python expression from C?,  Prev: Writing C is hard; are there any alternatives?,  Up: Extending/Embedding FAQ

10.5.4 How can I execute arbitrary Python statements from C?
------------------------------------------------------------

The highest-level function to do this is *note PyRun_SimpleString():
4bd6. which takes a single string argument to be executed in the context
of the module ‘__main__’ and returns ‘0’ for success and ‘-1’ when an
exception occurred (including *note SyntaxError: 18d.).  If you want
more control, use *note PyRun_String(): 1b6b.; see the source for
‘PyRun_SimpleString()’ in ‘Python/pythonrun.c’.


File: python.info,  Node: How can I evaluate an arbitrary Python expression from C?,  Next: How do I extract C values from a Python object?,  Prev: How can I execute arbitrary Python statements from C?,  Up: Extending/Embedding FAQ

10.5.5 How can I evaluate an arbitrary Python expression from C?
----------------------------------------------------------------

Call the function *note PyRun_String(): 1b6b. from the previous question
with the start symbol *note Py_eval_input: 4e7f.; it parses an
expression, evaluates it and returns its value.


File: python.info,  Node: How do I extract C values from a Python object?,  Next: How do I use Py_BuildValue to create a tuple of arbitrary length?,  Prev: How can I evaluate an arbitrary Python expression from C?,  Up: Extending/Embedding FAQ

10.5.6 How do I extract C values from a Python object?
------------------------------------------------------

That depends on the object’s type.  If it’s a tuple, *note
PyTuple_Size(): 4da0. returns its length and *note PyTuple_GetItem():
4b82. returns the item at a specified index.  Lists have similar
functions, *note PyList_Size(): 1468. and *note PyList_GetItem(): 35d.

For bytes, *note PyBytes_Size(): 4c49. returns its length and *note
PyBytes_AsStringAndSize(): 4c41. provides a pointer to its value and its
length.  Note that Python bytes objects may contain null bytes so C’s
‘strlen()’ should not be used.

To test the type of an object, first make sure it isn’t ‘NULL’, and then
use *note PyBytes_Check(): 13ec, *note PyTuple_Check(): 5035, *note
PyList_Check(): 5046, etc.

There is also a high-level API to Python objects which is provided by
the so-called ‘abstract’ interface – read ‘Include/abstract.h’ for
further details.  It allows interfacing with any kind of Python sequence
using calls like *note PySequence_Length(): 4d70, *note
PySequence_GetItem(): 1be5, etc.  as well as many other useful protocols
such as numbers (*note PyNumber_Index(): 89a. et al.)  and mappings in
the PyMapping APIs.


File: python.info,  Node: How do I use Py_BuildValue to create a tuple of arbitrary length?,  Next: How do I call an object’s method from C?,  Prev: How do I extract C values from a Python object?,  Up: Extending/Embedding FAQ

10.5.7 How do I use Py_BuildValue() to create a tuple of arbitrary length?
--------------------------------------------------------------------------

You can’t.  Use *note PyTuple_Pack(): 4d9f. instead.


File: python.info,  Node: How do I call an object’s method from C?,  Next: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?,  Prev: How do I use Py_BuildValue to create a tuple of arbitrary length?,  Up: Extending/Embedding FAQ

10.5.8 How do I call an object’s method from C?
-----------------------------------------------

The *note PyObject_CallMethod(): 3a2. function can be used to call an
arbitrary method of an object.  The parameters are the object, the name
of the method to call, a format string like that used with *note
Py_BuildValue(): 8af, and the argument values:

     PyObject *
     PyObject_CallMethod(PyObject *object, const char *method_name,
                         const char *arg_format, ...);

This works for any object that has methods – whether built-in or
user-defined.  You are responsible for eventually *note Py_DECREF():
572.‘ing the return value.

To call, e.g., a file object’s “seek” method with arguments 10, 0
(assuming the file object pointer is “f”):

     res = PyObject_CallMethod(f, "seek", "(ii)", 10, 0);
     if (res == NULL) {
             ... an exception occurred ...
     }
     else {
             Py_DECREF(res);
     }

Note that since *note PyObject_CallObject(): 4b77. 'always' wants a
tuple for the argument list, to call a function without arguments, pass
“()” for the format, and to call a function with one argument, surround
the argument in parentheses, e.g.  “(i)”.


File: python.info,  Node: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?,  Next: How do I access a module written in Python from C?,  Prev: How do I call an object’s method from C?,  Up: Extending/Embedding FAQ

10.5.9 How do I catch the output from PyErr_Print() (or anything that prints to stdout/stderr)?
-----------------------------------------------------------------------------------------------

In Python code, define an object that supports the ‘write()’ method.
Assign this object to *note sys.stdout: aec. and *note sys.stderr: 943.
Call print_error, or just allow the standard traceback mechanism to
work.  Then, the output will go wherever your ‘write()’ method sends it.

The easiest way to do this is to use the *note io.StringIO: f5e. class:

     >>> import io, sys
     >>> sys.stdout = io.StringIO()
     >>> print('foo')
     >>> print('hello world!')
     >>> sys.stderr.write(sys.stdout.getvalue())
     foo
     hello world!

A custom object to do the same would look like this:

     >>> import io, sys
     >>> class StdoutCatcher(io.TextIOBase):
     ...     def __init__(self):
     ...         self.data = []
     ...     def write(self, stuff):
     ...         self.data.append(stuff)
     ...
     >>> import sys
     >>> sys.stdout = StdoutCatcher()
     >>> print('foo')
     >>> print('hello world!')
     >>> sys.stderr.write(''.join(sys.stdout.data))
     foo
     hello world!


File: python.info,  Node: How do I access a module written in Python from C?,  Next: How do I interface to C++ objects from Python?,  Prev: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?,  Up: Extending/Embedding FAQ

10.5.10 How do I access a module written in Python from C?
----------------------------------------------------------

You can get a pointer to the module object as follows:

     module = PyImport_ImportModule("<modulename>");

If the module hasn’t been imported yet (i.e.  it is not yet present in
*note sys.modules: 1655.), this initializes the module; otherwise it
simply returns the value of ‘sys.modules["<modulename>"]’.  Note that it
doesn’t enter the module into any namespace – it only ensures it has
been initialized and is stored in ‘sys.modules’.

You can then access the module’s attributes (i.e.  any name defined in
the module) as follows:

     attr = PyObject_GetAttrString(module, "<attrname>");

Calling *note PyObject_SetAttrString(): 170a. to assign to variables in
the module also works.


File: python.info,  Node: How do I interface to C++ objects from Python?,  Next: I added a module using the Setup file and the make fails; why?,  Prev: How do I access a module written in Python from C?,  Up: Extending/Embedding FAQ

10.5.11 How do I interface to C++ objects from Python?
------------------------------------------------------

Depending on your requirements, there are many approaches.  To do this
manually, begin by reading *note the “Extending and Embedding” document:
1d6e.  Realize that for the Python run-time system, there isn’t a whole
lot of difference between C and C++ – so the strategy of building a new
Python type around a C structure (pointer) type will also work for C++
objects.

For C++ libraries, see *note Writing C is hard; are there any
alternatives?: 55ca.


File: python.info,  Node: I added a module using the Setup file and the make fails; why?,  Next: How do I debug an extension?,  Prev: How do I interface to C++ objects from Python?,  Up: Extending/Embedding FAQ

10.5.12 I added a module using the Setup file and the make fails; why?
----------------------------------------------------------------------

Setup must end in a newline, if there is no newline there, the build
process fails.  (Fixing this requires some ugly shell script hackery,
and this bug is so minor that it doesn’t seem worth the effort.)


File: python.info,  Node: How do I debug an extension?,  Next: I want to compile a Python module on my Linux system but some files are missing Why?,  Prev: I added a module using the Setup file and the make fails; why?,  Up: Extending/Embedding FAQ

10.5.13 How do I debug an extension?
------------------------------------

When using GDB with dynamically loaded extensions, you can’t set a
breakpoint in your extension until your extension is loaded.

In your ‘.gdbinit’ file (or interactively), add the command:

     br _PyImport_LoadDynamicModule

Then, when you run GDB:

     $ gdb /local/bin/python
     gdb) run myscript.py
     gdb) continue # repeat until your extension is loaded
     gdb) finish   # so that your extension is loaded
     gdb) br myfunction.c:50
     gdb) continue


File: python.info,  Node: I want to compile a Python module on my Linux system but some files are missing Why?,  Next: How do I tell “incomplete input” from “invalid input”?,  Prev: How do I debug an extension?,  Up: Extending/Embedding FAQ

10.5.14 I want to compile a Python module on my Linux system, but some files are missing. Why?
----------------------------------------------------------------------------------------------

Most packaged versions of Python omit some files required for compiling
Python extensions.

For Red Hat, install the python3-devel RPM to get the necessary files.

For Debian, run ‘apt-get install python3-dev’.


File: python.info,  Node: How do I tell “incomplete input” from “invalid input”?,  Next: How do I find undefined g++ symbols __builtin_new or __pure_virtual?,  Prev: I want to compile a Python module on my Linux system but some files are missing Why?,  Up: Extending/Embedding FAQ

10.5.15 How do I tell “incomplete input” from “invalid input”?
--------------------------------------------------------------

Sometimes you want to emulate the Python interactive interpreter’s
behavior, where it gives you a continuation prompt when the input is
incomplete (e.g.  you typed the start of an “if” statement or you didn’t
close your parentheses or triple string quotes), but it gives you a
syntax error message immediately when the input is invalid.

In Python you can use the *note codeop: 1c. module, which approximates
the parser’s behavior sufficiently.  IDLE uses this, for example.

The easiest way to do it in C is to call *note PyRun_InteractiveLoop():
4e87. (perhaps in a separate thread) and let the Python interpreter
handle the input for you.  You can also set the *note
PyOS_ReadlineFunctionPointer(): 589. to point at your custom input
function.  See ‘Modules/readline.c’ and ‘Parser/myreadline.c’ for more
hints.


File: python.info,  Node: How do I find undefined g++ symbols __builtin_new or __pure_virtual?,  Next: Can I create an object class with some methods implemented in C and others in Python e g through inheritance ?,  Prev: How do I tell “incomplete input” from “invalid input”?,  Up: Extending/Embedding FAQ

10.5.16 How do I find undefined g++ symbols __builtin_new or __pure_virtual?
----------------------------------------------------------------------------

To dynamically load g++ extension modules, you must recompile Python,
relink it using g++ (change LINKCC in the Python Modules Makefile), and
link your extension module using g++ (e.g., ‘g++ -shared -o mymodule.so
mymodule.o’).


File: python.info,  Node: Can I create an object class with some methods implemented in C and others in Python e g through inheritance ?,  Prev: How do I find undefined g++ symbols __builtin_new or __pure_virtual?,  Up: Extending/Embedding FAQ

10.5.17 Can I create an object class with some methods implemented in C and others in Python (e.g. through inheritance)?
------------------------------------------------------------------------------------------------------------------------

Yes, you can inherit from built-in classes such as *note int: 257, *note
list: 614, *note dict: 256, etc.

The Boost Python Library (BPL,
‘https://www.boost.org/libs/python/doc/index.html’) provides a way of
doing this from C++ (i.e.  you can inherit from an extension class
written in C++ using the BPL).


File: python.info,  Node: Python on Windows FAQ,  Next: Graphic User Interface FAQ,  Prev: Extending/Embedding FAQ,  Up: Python Frequently Asked Questions

10.6 Python on Windows FAQ
==========================

* Menu:

* How do I run a Python program under Windows?::
* How do I make Python scripts executable?::
* Why does Python sometimes take so long to start?::
* How do I make an executable from a Python script?::
* Is a *.pyd file the same as a DLL?: Is a * pyd file the same as a DLL?.
* How can I embed Python into a Windows application?::
* How do I keep editors from inserting tabs into my Python source?::
* How do I check for a keypress without blocking?::
* How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?.


File: python.info,  Node: How do I run a Python program under Windows?,  Next: How do I make Python scripts executable?,  Up: Python on Windows FAQ

10.6.1 How do I run a Python program under Windows?
---------------------------------------------------

This is not necessarily a straightforward question.  If you are already
familiar with running programs from the Windows command line then
everything will seem obvious; otherwise, you might need a little more
guidance.

Unless you use some sort of integrated development environment, you will
end up 'typing' Windows commands into what is referred to as a “Command
prompt window”.  Usually you can create such a window from your search
bar by searching for ‘cmd’.  You should be able to recognize when you
have started such a window because you will see a Windows “command
prompt”, which usually looks like this:

     C:\>

The letter may be different, and there might be other things after it,
so you might just as easily see something like:

     D:\YourName\Projects\Python>

depending on how your computer has been set up and what else you have
recently done with it.  Once you have started such a window, you are
well on the way to running Python programs.

You need to realize that your Python scripts have to be processed by
another program called the Python 'interpreter'.  The interpreter reads
your script, compiles it into bytecodes, and then executes the bytecodes
to run your program.  So, how do you arrange for the interpreter to
handle your Python?

First, you need to make sure that your command window recognises the
word “py” as an instruction to start the interpreter.  If you have
opened a command window, you should try entering the command ‘py’ and
hitting return:

     C:\Users\YourName> py

You should then see something like:

     Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
     Type "help", "copyright", "credits" or "license" for more information.
     >>>

You have started the interpreter in “interactive mode”.  That means you
can enter Python statements or expressions interactively and have them
executed or evaluated while you wait.  This is one of Python’s strongest
features.  Check it by entering a few expressions of your choice and
seeing the results:

     >>> print("Hello")
     Hello
     >>> "Hello" * 3
     'HelloHelloHello'

Many people use the interactive mode as a convenient yet highly
programmable calculator.  When you want to end your interactive Python
session, call the *note exit(): 2343. function or hold the ‘Ctrl’ key
down while you enter a ‘Z’, then hit the “‘Enter’” key to get back to
your Windows command prompt.

You may also find that you have a Start-menu entry such as Start ‣
Programs ‣ Python 3.x ‣ Python (command line) that results in you seeing
the ‘>>>’ prompt in a new window.  If so, the window will disappear
after you call the *note exit(): 2343. function or enter the ‘Ctrl’-‘Z’
character; Windows is running a single “python” command in the window,
and closes it when you terminate the interpreter.

Now that we know the ‘py’ command is recognized, you can give your
Python script to it.  You’ll have to give either an absolute or a
relative path to the Python script.  Let’s say your Python script is
located in your desktop and is named ‘hello.py’, and your command prompt
is nicely opened in your home directory so you’re seeing something
similar to:

     C:\Users\YourName>

So now you’ll ask the ‘py’ command to give your script to Python by
typing ‘py’ followed by your script path:

     C:\Users\YourName> py Desktop\hello.py
     hello


File: python.info,  Node: How do I make Python scripts executable?,  Next: Why does Python sometimes take so long to start?,  Prev: How do I run a Python program under Windows?,  Up: Python on Windows FAQ

10.6.2 How do I make Python scripts executable?
-----------------------------------------------

On Windows, the standard Python installer already associates the .py
extension with a file type (Python.File) and gives that file type an
open command that runs the interpreter (‘D:\Program
Files\Python\python.exe "%1" %*’).  This is enough to make scripts
executable from the command prompt as ‘foo.py’.  If you’d rather be able
to execute the script by simple typing ‘foo’ with no extension you need
to add .py to the PATHEXT environment variable.


File: python.info,  Node: Why does Python sometimes take so long to start?,  Next: How do I make an executable from a Python script?,  Prev: How do I make Python scripts executable?,  Up: Python on Windows FAQ

10.6.3 Why does Python sometimes take so long to start?
-------------------------------------------------------

Usually Python starts very quickly on Windows, but occasionally there
are bug reports that Python suddenly begins to take a long time to start
up.  This is made even more puzzling because Python will work fine on
other Windows systems which appear to be configured identically.

The problem may be caused by a misconfiguration of virus checking
software on the problem machine.  Some virus scanners have been known to
introduce startup overhead of two orders of magnitude when the scanner
is configured to monitor all reads from the filesystem.  Try checking
the configuration of virus scanning software on your systems to ensure
that they are indeed configured identically.  McAfee, when configured to
scan all file system read activity, is a particular offender.


File: python.info,  Node: How do I make an executable from a Python script?,  Next: Is a * pyd file the same as a DLL?,  Prev: Why does Python sometimes take so long to start?,  Up: Python on Windows FAQ

10.6.4 How do I make an executable from a Python script?
--------------------------------------------------------

See *note How can I create a stand-alone binary from a Python script?:
5536. for a list of tools that can be used to make executables.


File: python.info,  Node: Is a * pyd file the same as a DLL?,  Next: How can I embed Python into a Windows application?,  Prev: How do I make an executable from a Python script?,  Up: Python on Windows FAQ

10.6.5 Is a ‘*.pyd’ file the same as a DLL?
-------------------------------------------

Yes, .pyd files are dll’s, but there are a few differences.  If you have
a DLL named ‘foo.pyd’, then it must have a function ‘PyInit_foo()’.  You
can then write Python “import foo”, and Python will search for foo.pyd
(as well as foo.py, foo.pyc) and if it finds it, will attempt to call
‘PyInit_foo()’ to initialize it.  You do not link your .exe with
foo.lib, as that would cause Windows to require the DLL to be present.

Note that the search path for foo.pyd is PYTHONPATH, not the same as the
path that Windows uses to search for foo.dll.  Also, foo.pyd need not be
present to run your program, whereas if you linked your program with a
dll, the dll is required.  Of course, foo.pyd is required if you want to
say ‘import foo’.  In a DLL, linkage is declared in the source code with
‘__declspec(dllexport)’.  In a .pyd, linkage is defined in a list of
available functions.


File: python.info,  Node: How can I embed Python into a Windows application?,  Next: How do I keep editors from inserting tabs into my Python source?,  Prev: Is a * pyd file the same as a DLL?,  Up: Python on Windows FAQ

10.6.6 How can I embed Python into a Windows application?
---------------------------------------------------------

Embedding the Python interpreter in a Windows app can be summarized as
follows:

  1. Do 'not' build Python into your .exe file directly.  On Windows,
     Python must be a DLL to handle importing modules that are
     themselves DLL’s.  (This is the first key undocumented fact.)
     Instead, link to ‘python`NN'.dll’; it is typically installed in
     ‘C:\Windows\System’.  'NN' is the Python version, a number such as
     “33” for Python 3.3.

     You can link to Python in two different ways.  Load-time linking
     means linking against ‘python`NN'.lib’, while run-time linking
     means linking against ‘python`NN'.dll’.  (General note:
     ‘python`NN'.lib’ is the so-called “import lib” corresponding to
     ‘python`NN'.dll’.  It merely defines symbols for the linker.)

     Run-time linking greatly simplifies link options; everything
     happens at run time.  Your code must load ‘python`NN'.dll’ using
     the Windows ‘LoadLibraryEx()’ routine.  The code must also use
     access routines and data in ‘python`NN'.dll’ (that is, Python’s C
     API’s) using pointers obtained by the Windows ‘GetProcAddress()’
     routine.  Macros can make using these pointers transparent to any C
     code that calls routines in Python’s C API.

  2. If you use SWIG, it is easy to create a Python “extension module”
     that will make the app’s data and methods available to Python.
     SWIG will handle just about all the grungy details for you.  The
     result is C code that you link 'into' your .exe file (!)  You do
     'not' have to create a DLL file, and this also simplifies linking.

  3. SWIG will create an init function (a C function) whose name depends
     on the name of the extension module.  For example, if the name of
     the module is leo, the init function will be called initleo().  If
     you use SWIG shadow classes, as you should, the init function will
     be called initleoc().  This initializes a mostly hidden helper
     class used by the shadow class.

     The reason you can link the C code in step 2 into your .exe file is
     that calling the initialization function is equivalent to importing
     the module into Python!  (This is the second key undocumented
     fact.)

  4. In short, you can use the following code to initialize the Python
     interpreter with your extension module.

          #include <Python.h>
          ...
          Py_Initialize();  // Initialize Python.
          initmyAppc();  // Initialize (import) the helper class.
          PyRun_SimpleString("import myApp");  // Import the shadow class.

  5. There are two problems with Python’s C API which will become
     apparent if you use a compiler other than MSVC, the compiler used
     to build pythonNN.dll.

     Problem 1: The so-called “Very High Level” functions that take
     ‘FILE *’ arguments will not work in a multi-compiler environment
     because each compiler’s notion of a ‘struct FILE’ will be
     different.  From an implementation standpoint these are very low
     level functions.

     Problem 2: SWIG generates the following code when generating
     wrappers to void functions:

          Py_INCREF(Py_None);
          _resultobj = Py_None;
          return _resultobj;

     Alas, Py_None is a macro that expands to a reference to a complex
     data structure called _Py_NoneStruct inside pythonNN.dll.  Again,
     this code will fail in a mult-compiler environment.  Replace such
     code by:

          return Py_BuildValue("");

     It may be possible to use SWIG’s ‘%typemap’ command to make the
     change automatically, though I have not been able to get this to
     work (I’m a complete SWIG newbie).

  6. Using a Python shell script to put up a Python interpreter window
     from inside your Windows app is not a good idea; the resulting
     window will be independent of your app’s windowing system.  Rather,
     you (or the wxPythonWindow class) should create a “native”
     interpreter window.  It is easy to connect that window to the
     Python interpreter.  You can redirect Python’s i/o to _any_ object
     that supports read and write, so all you need is a Python object
     (defined in your extension module) that contains read() and write()
     methods.


File: python.info,  Node: How do I keep editors from inserting tabs into my Python source?,  Next: How do I check for a keypress without blocking?,  Prev: How can I embed Python into a Windows application?,  Up: Python on Windows FAQ

10.6.7 How do I keep editors from inserting tabs into my Python source?
-----------------------------------------------------------------------

The FAQ does not recommend using tabs, and the Python style guide, PEP
8(1), recommends 4 spaces for distributed Python code; this is also the
Emacs python-mode default.

Under any editor, mixing tabs and spaces is a bad idea.  MSVC is no
different in this respect, and is easily configured to use spaces: Take
Tools ‣ Options ‣ Tabs, and for file type “Default” set “Tab size” and
“Indent size” to 4, and select the “Insert spaces” radio button.

Python raises *note IndentationError: 7ac. or *note TabError: 546. if
mixed tabs and spaces are causing problems in leading whitespace.  You
may also run the *note tabnanny: dd. module to check a directory tree in
batch mode.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0008/


File: python.info,  Node: How do I check for a keypress without blocking?,  Next: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?,  Prev: How do I keep editors from inserting tabs into my Python source?,  Up: Python on Windows FAQ

10.6.8 How do I check for a keypress without blocking?
------------------------------------------------------

Use the *note msvcrt: 93. module.  This is a standard Windows-specific
extension module.  It defines a function ‘kbhit()’ which checks whether
a keyboard hit is present, and ‘getch()’ which gets one character
without echoing it.


File: python.info,  Node: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?,  Prev: How do I check for a keypress without blocking?,  Up: Python on Windows FAQ

10.6.9 How do I solve the missing api-ms-win-crt-runtime-l1-1-0.dll error?
--------------------------------------------------------------------------

This can occur on Python 3.5 and later when using Windows 8.1 or earlier
without all updates having been installed.  First ensure your operating
system is supported and is up to date, and if that does not resolve the
issue, visit the Microsoft support page(1) for guidance on manually
installing the C Runtime update.

   ---------- Footnotes ----------

   (1) https://support.microsoft.com/en-us/help/3118401/


File: python.info,  Node: Graphic User Interface FAQ,  Next: “Why is Python Installed on my Computer?” FAQ,  Prev: Python on Windows FAQ,  Up: Python Frequently Asked Questions

10.7 Graphic User Interface FAQ
===============================

* Menu:

* General GUI Questions::
* What GUI toolkits exist for Python?::
* Tkinter questions::


File: python.info,  Node: General GUI Questions,  Next: What GUI toolkits exist for Python?,  Up: Graphic User Interface FAQ

10.7.1 General GUI Questions
----------------------------


File: python.info,  Node: What GUI toolkits exist for Python?,  Next: Tkinter questions,  Prev: General GUI Questions,  Up: Graphic User Interface FAQ

10.7.2 What GUI toolkits exist for Python?
------------------------------------------

Standard builds of Python include an object-oriented interface to the
Tcl/Tk widget set, called *note tkinter: 3fbb.  This is probably the
easiest to install (since it comes included with most binary
distributions(1) of Python) and use.  For more info about Tk, including
pointers to the source, see the Tcl/Tk home page(2).  Tcl/Tk is fully
portable to the macOS, Windows, and Unix platforms.

Depending on what platform(s) you are aiming at, there are also several
alternatives.  A list of cross-platform(3) and platform-specific(4) GUI
frameworks can be found on the python wiki.

   ---------- Footnotes ----------

   (1) https://www.python.org/downloads/

   (2) https://www.tcl.tk

   (3) 
https://wiki.python.org/moin/GuiProgramming#Cross-Platform_Frameworks

   (4) 
https://wiki.python.org/moin/GuiProgramming#Platform-specific_Frameworks


File: python.info,  Node: Tkinter questions,  Prev: What GUI toolkits exist for Python?,  Up: Graphic User Interface FAQ

10.7.3 Tkinter questions
------------------------

* Menu:

* How do I freeze Tkinter applications?::
* Can I have Tk events handled while waiting for I/O?::
* I can’t get key bindings to work in Tkinter; why?: I can’t get key bindings to work in Tkinter why?.


File: python.info,  Node: How do I freeze Tkinter applications?,  Next: Can I have Tk events handled while waiting for I/O?,  Up: Tkinter questions

10.7.3.1 How do I freeze Tkinter applications?
..............................................

Freeze is a tool to create stand-alone applications.  When freezing
Tkinter applications, the applications will not be truly stand-alone, as
the application will still need the Tcl and Tk libraries.

One solution is to ship the application with the Tcl and Tk libraries,
and point to them at run-time using the ‘TCL_LIBRARY’ and ‘TK_LIBRARY’
environment variables.

Various third-party freeze libraries such as py2exe and cx_Freeze have
handling for Tkinter applications built-in.


File: python.info,  Node: Can I have Tk events handled while waiting for I/O?,  Next: I can’t get key bindings to work in Tkinter why?,  Prev: How do I freeze Tkinter applications?,  Up: Tkinter questions

10.7.3.2 Can I have Tk events handled while waiting for I/O?
............................................................

On platforms other than Windows, yes, and you don’t even need threads!
But you’ll have to restructure your I/O code a bit.  Tk has the
equivalent of Xt’s ‘XtAddInput()’ call, which allows you to register a
callback function which will be called from the Tk mainloop when I/O is
possible on a file descriptor.  See *note File Handlers: 3fd9.


File: python.info,  Node: I can’t get key bindings to work in Tkinter why?,  Prev: Can I have Tk events handled while waiting for I/O?,  Up: Tkinter questions

10.7.3.3 I can’t get key bindings to work in Tkinter: why?
..........................................................

An often-heard complaint is that event handlers *note bound: 3fd4. to
events with the ‘bind()’ method don’t get handled even when the
appropriate key is pressed.

The most common cause is that the widget to which the binding applies
doesn’t have “keyboard focus”.  Check out the Tk documentation for the
focus command.  Usually a widget is given the keyboard focus by clicking
in it (but not for labels; see the takefocus option).


File: python.info,  Node: “Why is Python Installed on my Computer?” FAQ,  Prev: Graphic User Interface FAQ,  Up: Python Frequently Asked Questions

10.8 “Why is Python Installed on my Computer?” FAQ
==================================================

* Menu:

* What is Python?: What is Python?<2>.
* Why is Python installed on my machine?::
* Can I delete Python?::


File: python.info,  Node: What is Python?<2>,  Next: Why is Python installed on my machine?,  Up: “Why is Python Installed on my Computer?” FAQ

10.8.1 What is Python?
----------------------

Python is a programming language.  It’s used for many different
applications.  It’s used in some high schools and colleges as an
introductory programming language because Python is easy to learn, but
it’s also used by professional software developers at places such as
Google, NASA, and Lucasfilm Ltd.

If you wish to learn more about Python, start with the Beginner's Guide
to Python(1).

   ---------- Footnotes ----------

   (1) https://wiki.python.org/moin/BeginnersGuide


File: python.info,  Node: Why is Python installed on my machine?,  Next: Can I delete Python?,  Prev: What is Python?<2>,  Up: “Why is Python Installed on my Computer?” FAQ

10.8.2 Why is Python installed on my machine?
---------------------------------------------

If you find Python installed on your system but don’t remember
installing it, there are several possible ways it could have gotten
there.

   * Perhaps another user on the computer wanted to learn programming
     and installed it; you’ll have to figure out who’s been using the
     machine and might have installed it.

   * A third-party application installed on the machine might have been
     written in Python and included a Python installation.  There are
     many such applications, from GUI programs to network servers and
     administrative scripts.

   * Some Windows machines also have Python installed.  At this writing
     we’re aware of computers from Hewlett-Packard and Compaq that
     include Python.  Apparently some of HP/Compaq’s administrative
     tools are written in Python.

   * Many Unix-compatible operating systems, such as macOS and some
     Linux distributions, have Python installed by default; it’s
     included in the base installation.


File: python.info,  Node: Can I delete Python?,  Prev: Why is Python installed on my machine?,  Up: “Why is Python Installed on my Computer?” FAQ

10.8.3 Can I delete Python?
---------------------------

That depends on where Python came from.

If someone installed it deliberately, you can remove it without hurting
anything.  On Windows, use the Add/Remove Programs icon in the Control
Panel.

If Python was installed by a third-party application, you can also
remove it, but that application will no longer work.  You should use
that application’s uninstaller rather than removing Python directly.

If Python came with your operating system, removing it is not
recommended.  If you remove it, whatever tools were written in Python
will no longer run, and some of them might be important to you.
Reinstalling the whole system would then be required to fix things
again.


File: python.info,  Node: Deprecations,  Next: Glossary,  Prev: Python Frequently Asked Questions,  Up: Top

11 Deprecations
***************

* Menu:

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<5>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<5>.
* Pending removal in Python 3.16: Pending removal in Python 3 16<5>.
* Pending removal in Python 3.17: Pending removal in Python 3 17<3>.
* Pending removal in Python 3.18: Pending removal in Python 3 18<2>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<5>.
* C API Deprecations::


File: python.info,  Node: Pending Removal in Python 3 14<5>,  Next: Pending Removal in Python 3 15<5>,  Up: Deprecations

11.1 Pending Removal in Python 3.14
===================================

   * *note argparse: 6.: The 'type', 'choices', and 'metavar' parameters
     of ‘argparse.BooleanOptionalAction’ are deprecated and will be
     removed in 3.14.  (Contributed by Nikita Sobolev in gh-92248(1).)

   * *note ast: 8.: The following features have been deprecated in
     documentation since Python 3.8, now cause a *note
     DeprecationWarning: 1a5. to be emitted at runtime when they are
     accessed or used, and will be removed in Python 3.14:

        * ‘ast.Num’

        * ‘ast.Str’

        * ‘ast.Bytes’

        * ‘ast.NameConstant’

        * ‘ast.Ellipsis’

     Use *note ast.Constant: 2b9. instead.  (Contributed by Serhiy
     Storchaka in gh-90953(2).)

   * *note asyncio: a.:

        * The child watcher classes *note MultiLoopChildWatcher: 2ba,
          *note FastChildWatcher: 2bb, *note AbstractChildWatcher: 2bc.
          and *note SafeChildWatcher: 2bd. are deprecated and will be
          removed in Python 3.14.  (Contributed by Kumar Aditya in
          gh-94597(3).)

        * *note asyncio.set_child_watcher(): 2be, *note
          asyncio.get_child_watcher(): 2bf, *note
          asyncio.AbstractEventLoopPolicy.set_child_watcher(): 2c0. and
          *note asyncio.AbstractEventLoopPolicy.get_child_watcher():
          2c1. are deprecated and will be removed in Python 3.14.
          (Contributed by Kumar Aditya in gh-94597(4).)

        * The *note get_event_loop(): 2c2. method of the default event
          loop policy now emits a *note DeprecationWarning: 1a5. if
          there is no current event loop set and it decides to create
          one.  (Contributed by Serhiy Storchaka and Guido van Rossum in
          gh-100160(5).)

   * *note builtins: 12.: ‘bool(NotImplemented)’ now emits a *note
     DeprecationWarning: 1a5. and will raise a *note TypeError: 2c3. in
     Python 3.14.  (Contributed by Jelle Zijlstra in gh-118767(6).)

   * *note email: 3b.: Deprecated the 'isdst' parameter in *note
     email.utils.localtime(): 2c4.  (Contributed by Alan Williams in
     gh-72346(7).)

   * *note importlib.abc: 78. deprecated classes:

        * ‘importlib.abc.ResourceReader’

        * ‘importlib.abc.Traversable’

        * ‘importlib.abc.TraversableResources’

     Use *note importlib.resources.abc: 7c. classes instead:

        * *note importlib.resources.abc.Traversable: 1f3.

        * *note importlib.resources.abc.TraversableResources: 2c5.

     (Contributed by Jason R. Coombs and Hugo van Kemenade in
     gh-93963(8).)

   * *note itertools: 81. had undocumented, inefficient, historically
     buggy, and inconsistent support for copy, deepcopy, and pickle
     operations.  This will be removed in 3.14 for a significant
     reduction in code volume and maintenance burden.  (Contributed by
     Raymond Hettinger in gh-101588(9).)

   * *note multiprocessing: 94.: The default start method will change to
     a safer one on Linux, BSDs, and other non-macOS POSIX platforms
     where ‘'fork'’ is currently the default (gh-84559(10)).  Adding a
     runtime warning about this was deemed too disruptive as the
     majority of code is not expected to care.  Use the *note
     get_context(): 2c6. or *note set_start_method(): 2c7. APIs to
     explicitly specify when your code 'requires' ‘'fork'’.  See *note
     Contexts and start methods: 2c8.

   * *note pathlib: a4.: *note is_relative_to(): 2c9. and *note
     relative_to(): 2ca.: passing additional arguments is deprecated.

   * *note pkgutil: a9.: *note find_loader(): 2cb. and *note
     get_loader(): 2cc. now raise *note DeprecationWarning: 1a5.; use
     *note importlib.util.find_spec(): 2cd. instead.  (Contributed by
     Nikita Sobolev in gh-97850(11).)

   * *note pty: b1.:

        * ‘master_open()’: use *note pty.openpty(): 2ce.

        * ‘slave_open()’: use *note pty.openpty(): 2ce.

   * *note sqlite3: cf.:

        * *note version: 2cf. and *note version_info: 2d0.

        * *note execute(): 2d1. and *note executemany(): 2d2. if *note
          named placeholders: 2d3. are used and 'parameters' is a
          sequence instead of a *note dict: 256.

   * *note urllib: 108.: ‘urllib.parse.Quoter’ is deprecated: it was not
     intended to be a public API. (Contributed by Gregory P. Smith in
     gh-88168(12).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/92248

   (2) https://github.com/python/cpython/issues/90953

   (3) https://github.com/python/cpython/issues/94597

   (4) https://github.com/python/cpython/issues/94597

   (5) https://github.com/python/cpython/issues/100160

   (6) https://github.com/python/cpython/issues/118767

   (7) https://github.com/python/cpython/issues/72346

   (8) https://github.com/python/cpython/issues/93963

   (9) https://github.com/python/cpython/issues/101588

   (10) https://github.com/python/cpython/issues/84559

   (11) https://github.com/python/cpython/issues/97850

   (12) https://github.com/python/cpython/issues/88168


File: python.info,  Node: Pending Removal in Python 3 15<5>,  Next: Pending removal in Python 3 16<5>,  Prev: Pending Removal in Python 3 14<5>,  Up: Deprecations

11.2 Pending Removal in Python 3.15
===================================

   * The import system:

        * Setting *note __cached__: 2d5. on a module while failing to
          set *note __spec__.cached: 2d6. is deprecated.  In Python
          3.15, ‘__cached__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(1))

        * Setting *note __package__: 2d7. on a module while failing to
          set *note __spec__.parent: 2d8. is deprecated.  In Python
          3.15, ‘__package__’ will cease to be set or take into
          consideration by the import system or standard library.
          (gh-97879(2))

   * *note ctypes: 2a.:

        * The undocumented ‘ctypes.SetPointerType()’ function has been
          deprecated since Python 3.13.

   * *note http.server: 72.:

        * The obsolete and rarely used *note CGIHTTPRequestHandler: 2a1.
          has been deprecated since Python 3.13.  No direct replacement
          exists.  'Anything' is better than CGI to interface a web
          server with a request handler.

        * The ‘--cgi’ flag to the ‘python -m http.server’ command-line
          interface has been deprecated since Python 3.13.

   * *note importlib: 77.:

        * ‘load_module()’ method: use ‘exec_module()’ instead.

   * *note locale: 86.:

        * The *note getdefaultlocale(): 2d9. function has been
          deprecated since Python 3.11.  Its removal was originally
          planned for Python 3.13 (gh-90817(3)), but has been postponed
          to Python 3.15.  Use *note getlocale(): 2da, *note
          setlocale(): 2db, and *note getencoding(): 2dc. instead.
          (Contributed by Hugo van Kemenade in gh-111187(4).)

   * *note pathlib: a4.:

        * *note PurePath.is_reserved(): 2a6. has been deprecated since
          Python 3.13.  Use *note os.path.isreserved(): 223. to detect
          reserved paths on Windows.

   * *note platform: aa.:

        * *note java_ver(): 2a7. has been deprecated since Python 3.13.
          This function is only useful for Jython support, has a
          confusing API, and is largely untested.

   * *note sysconfig: db.:

        * The 'check_home' argument of *note
          sysconfig.is_python_build(): 2dd. has been deprecated since
          Python 3.12.

   * *note threading: ed.:

        * *note RLock(): 2de. will take no arguments in Python 3.15.
          Passing any arguments has been deprecated since Python 3.14,
          as the Python version does not permit any arguments, but the C
          version allows any number of positional or keyword arguments,
          ignoring every argument.

   * *note types: 103.:

        * *note types.CodeType: 2df.: Accessing *note co_lnotab: 2e0.
          was deprecated in PEP 626(5) since 3.10 and was planned to be
          removed in 3.12, but it only got a proper *note
          DeprecationWarning: 1a5. in 3.12.  May be removed in 3.15.
          (Contributed by Nikita Sobolev in gh-101866(6).)

   * *note typing: 104.:

        * The undocumented keyword argument syntax for creating *note
          NamedTuple: 2b0. classes (e.g.  ‘Point = NamedTuple("Point",
          x=int, y=int)’) has been deprecated since Python 3.13.  Use
          the class-based syntax or the functional syntax instead.

        * When using the functional syntax of *note TypedDict: 162.s,
          failing to pass a value to the 'fields' parameter (‘TD =
          TypedDict("TD")’) or passing ‘None’ (‘TD = TypedDict("TD",
          None)’) has been deprecated since Python 3.13.  Use ‘class
          TD(TypedDict): pass’ or ‘TD = TypedDict("TD", {})’ to create a
          TypedDict with zero field.

        * The *note typing.no_type_check_decorator(): 2b1. decorator
          function has been deprecated since Python 3.13.  After eight
          years in the *note typing: 104. module, it has yet to be
          supported by any major type checker.

   * *note wave: 113.:

        * The *note getmark(): 2b4, ‘setmark()’, and *note getmarkers():
          2b5. methods of the *note Wave_read: 2b6. and *note
          Wave_write: 2b7. classes have been deprecated since Python
          3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/97879

   (2) https://github.com/python/cpython/issues/97879

   (3) https://github.com/python/cpython/issues/90817

   (4) https://github.com/python/cpython/issues/111187

   (5) https://peps.python.org/pep-0626/

   (6) https://github.com/python/cpython/issues/101866


File: python.info,  Node: Pending removal in Python 3 16<5>,  Next: Pending removal in Python 3 17<3>,  Prev: Pending Removal in Python 3 15<5>,  Up: Deprecations

11.3 Pending removal in Python 3.16
===================================

   * The import system:

        * Setting *note __loader__: 2e2. on a module while failing to
          set *note __spec__.loader: 2e3. is deprecated.  In Python
          3.16, ‘__loader__’ will cease to be set or taken into
          consideration by the import system or the standard library.

   * *note array: 7.:

        * The ‘'u'’ format code (‘wchar_t’) has been deprecated in
          documentation since Python 3.3 and at runtime since Python
          3.13.  Use the ‘'w'’ format code (*note Py_UCS4: 29b.) for
          Unicode characters instead.

   * *note asyncio: a.:

        * ‘asyncio.iscoroutinefunction()’ is deprecated and will be
          removed in Python 3.16, use *note
          inspect.iscoroutinefunction(): 2e4. instead.  (Contributed by
          Jiahao Li and Kumar Aditya in gh-122875(1).)

   * *note builtins: 12.:

        * Bitwise inversion on boolean types, ‘~True’ or ‘~False’ has
          been deprecated since Python 3.12, as it produces surprising
          and unintuitive results (‘-2’ and ‘-1’).  Use ‘not x’ instead
          for the logical negation of a Boolean.  In the rare case that
          you need the bitwise inversion of the underlying integer,
          convert to ‘int’ explicitly (‘~int(x)’).

   * *note shutil: c5.:

        * The ‘ExecError’ exception has been deprecated since Python
          3.14.  It has not been used by any function in ‘shutil’ since
          Python 3.4, and is now an alias of *note RuntimeError: 195.

   * *note symtable: d8.:

        * The *note Class.get_methods: 2e5. method has been deprecated
          since Python 3.14.

   * *note sys: d9.:

        * The *note _enablelegacywindowsfsencoding(): 2ae. function has
          been deprecated since Python 3.13.  Use the *note
          PYTHONLEGACYWINDOWSFSENCODING: 2af. environment variable
          instead.

   * *note tarfile: de.:

        * The undocumented and unused ‘TarFile.tarfile’ attribute has
          been deprecated since Python 3.13.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/122875


File: python.info,  Node: Pending removal in Python 3 17<3>,  Next: Pending removal in Python 3 18<2>,  Prev: Pending removal in Python 3 16<5>,  Up: Deprecations

11.4 Pending removal in Python 3.17
===================================

   * *note collections.abc: 1e.:

        - *note collections.abc.ByteString: 2e7. is scheduled for
          removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(1) for more details.  (Contributed by Shantanu
          Jain in gh-91896(2).)

   * *note typing: 104.:

        - Before Python 3.14, old-style unions were implemented using
          the private class ‘typing._UnionGenericAlias’.  This class is
          no longer needed for the implementation, but it has been
          retained for backward compatibility, with removal scheduled
          for Python 3.17.  Users should use documented introspection
          helpers like *note typing.get_origin(): 2ec. and *note
          typing.get_args(): 2ed. instead of relying on private
          implementation details.

        - *note typing.ByteString: 2ee, deprecated since Python 3.9, is
          scheduled for removal in Python 3.17.

          Use ‘isinstance(obj, collections.abc.Buffer)’ to test if ‘obj’
          implements the *note buffer protocol: 2e8. at runtime.  For
          use in type annotations, either use *note Buffer: 2e9. or a
          union that explicitly specifies the types your code supports
          (e.g., ‘bytes | bytearray | memoryview’).

          ‘ByteString’ was originally intended to be an abstract class
          that would serve as a supertype of both *note bytes: 1c2. and
          *note bytearray: 2ea.  However, since the ABC never had any
          methods, knowing that an object was an instance of
          ‘ByteString’ never actually told you anything useful about the
          object.  Other common buffer types such as *note memoryview:
          2eb. were also never understood as subtypes of ‘ByteString’
          (either at runtime or by static type checkers).

          See PEP 688(3) for more details.  (Contributed by Shantanu
          Jain in gh-91896(4).)

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0688/#current-options

   (2) https://github.com/python/cpython/issues/91896

   (3) https://peps.python.org/pep-0688/#current-options

   (4) https://github.com/python/cpython/issues/91896


File: python.info,  Node: Pending removal in Python 3 18<2>,  Next: Pending Removal in Future Versions<5>,  Prev: Pending removal in Python 3 17<3>,  Up: Deprecations

11.5 Pending removal in Python 3.18
===================================

   * *note decimal: 36.:

        * The non-standard and undocumented *note Decimal: 29d. format
          specifier ‘'N'’, which is only supported in the ‘decimal’
          module’s C implementation, has been deprecated since Python
          3.13.  (Contributed by Serhiy Storchaka in gh-89902(1).)

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/89902


File: python.info,  Node: Pending Removal in Future Versions<5>,  Next: C API Deprecations,  Prev: Pending removal in Python 3 18<2>,  Up: Deprecations

11.6 Pending Removal in Future Versions
=======================================

The following APIs will be removed in the future, although there is
currently no date scheduled for their removal.

   * *note argparse: 6.: Nesting argument groups and nesting mutually
     exclusive groups are deprecated.

   * *note builtins: 12.:

        * Generators: ‘throw(type, exc, tb)’ and ‘athrow(type, exc, tb)’
          signature is deprecated: use ‘throw(exc)’ and ‘athrow(exc)’
          instead, the single argument signature.

        * Currently Python accepts numeric literals immediately followed
          by keywords, for example ‘0in x’, ‘1or x’, ‘0if 1else 2’.  It
          allows confusing and ambiguous expressions like ‘[0x1for x in
          y]’ (which can be interpreted as ‘[0x1 for x in y]’ or ‘[0x1f
          or x in y]’).  A syntax warning is raised if the numeric
          literal is immediately followed by one of keywords *note and:
          2f1, *note else: 18c, *note for: 2f2, *note if: 2f3, *note in:
          2f4, *note is: 2f5. and *note or: 2f6.  In a future release it
          will be changed to a syntax error.  (gh-87999(1))

        * Support for ‘__index__()’ and ‘__int__()’ method returning
          non-int type: these methods will be required to return an
          instance of a strict subclass of *note int: 257.

        * Support for ‘__float__()’ method returning a strict subclass
          of *note float: 2f7.: these methods will be required to return
          an instance of ‘float’.

        * Support for ‘__complex__()’ method returning a strict subclass
          of *note complex: 2f8.: these methods will be required to
          return an instance of ‘complex’.

        * Delegation of ‘int()’ to ‘__trunc__()’ method.

        * Passing a complex number as the 'real' or 'imag' argument in
          the *note complex(): 2f8. constructor is now deprecated; it
          should only be passed as a single positional argument.
          (Contributed by Serhiy Storchaka in gh-109218(2).)

   * *note calendar: 14.: ‘calendar.January’ and ‘calendar.February’
     constants are deprecated and replaced by *note calendar.JANUARY:
     2f9. and *note calendar.FEBRUARY: 2fa.  (Contributed by Prince
     Roshan in gh-103636(3).)

   * *note codeobject.co_lnotab: 2e0.: use the *note
     codeobject.co_lines(): 2fb. method instead.

   * *note datetime: 30.:

        * *note utcnow(): 2fc.: use
          ‘datetime.datetime.now(tz=datetime.UTC)’.

        * *note utcfromtimestamp(): 2fd.: use
          ‘datetime.datetime.fromtimestamp(timestamp, tz=datetime.UTC)’.

   * *note gettext: 63.: Plural value must be an integer.

   * *note importlib: 77.:

        * *note cache_from_source(): 2fe. 'debug_override' parameter is
          deprecated: use the 'optimization' parameter instead.

   * *note importlib.metadata: 7a.:

        * ‘EntryPoints’ tuple interface.

        * Implicit ‘None’ on return values.

   * *note logging: 87.: the ‘warn()’ method has been deprecated since
     Python 3.3, use *note warning(): 2ff. instead.

   * *note mailbox: 8b.: Use of StringIO input and text mode is
     deprecated, use BytesIO and binary mode instead.

   * *note os: a1.: Calling *note os.register_at_fork(): 300. in
     multi-threaded process.

   * ‘pydoc.ErrorDuringImport’: A tuple value for 'exc_info' parameter
     is deprecated, use an exception instance.

   * *note re: b9.: More strict rules are now applied for numerical
     group references and group names in regular expressions.  Only
     sequence of ASCII digits is now accepted as a numerical reference.
     The group name in bytes patterns and replacement strings can now
     only contain ASCII letters and digits and underscore.  (Contributed
     by Serhiy Storchaka in gh-91760(4).)

   * ‘sre_compile’, ‘sre_constants’ and ‘sre_parse’ modules.

   * *note shutil: c5.: *note rmtree(): 301.’s 'onerror' parameter is
     deprecated in Python 3.12; use the 'onexc' parameter instead.

   * *note ssl: d0. options and protocols:

        * *note ssl.SSLContext: 294. without protocol argument is
          deprecated.

        * *note ssl.SSLContext: 294.: *note set_npn_protocols(): 302.
          and ‘selected_npn_protocol()’ are deprecated: use ALPN
          instead.

        * ‘ssl.OP_NO_SSL*’ options

        * ‘ssl.OP_NO_TLS*’ options

        * ‘ssl.PROTOCOL_SSLv3’

        * ‘ssl.PROTOCOL_TLS’

        * ‘ssl.PROTOCOL_TLSv1’

        * ‘ssl.PROTOCOL_TLSv1_1’

        * ‘ssl.PROTOCOL_TLSv1_2’

        * ‘ssl.TLSVersion.SSLv3’

        * ‘ssl.TLSVersion.TLSv1’

        * ‘ssl.TLSVersion.TLSv1_1’

   * *note threading: ed. methods:

        * ‘threading.Condition.notifyAll()’: use *note notify_all():
          303.

        * ‘threading.Event.isSet()’: use *note is_set(): 304.

        * ‘threading.Thread.isDaemon()’, *note
          threading.Thread.setDaemon(): 305.: use *note
          threading.Thread.daemon: 306. attribute.

        * ‘threading.Thread.getName()’, *note
          threading.Thread.setName(): 307.: use *note
          threading.Thread.name: 308. attribute.

        * ‘threading.currentThread()’: use *note
          threading.current_thread(): 309.

        * ‘threading.activeCount()’: use *note threading.active_count():
          30a.

   * *note typing.Text: 30b. (gh-92332(5)).

   * *note unittest.IsolatedAsyncioTestCase: 30c.: it is deprecated to
     return a value that is not ‘None’ from a test case.

   * *note urllib.parse: 10a. deprecated functions: *note urlparse():
     30d. instead

        * ‘splitattr()’

        * ‘splithost()’

        * ‘splitnport()’

        * ‘splitpasswd()’

        * ‘splitport()’

        * ‘splitquery()’

        * ‘splittag()’

        * ‘splittype()’

        * ‘splituser()’

        * ‘splitvalue()’

        * ‘to_bytes()’

   * *note urllib.request: 10b.: *note URLopener: 30e. and *note
     FancyURLopener: 30f. style of invoking requests is deprecated.  Use
     newer *note urlopen(): 293. functions and methods.

   * *note wsgiref: 118.: ‘SimpleHandler.stdout.write()’ should not do
     partial writes.

   * *note xml.etree.ElementTree: 125.: Testing the truth value of an
     *note Element: 310. is deprecated.  In a future release it will
     always return ‘True’.  Prefer explicit ‘len(elem)’ or ‘elem is not
     None’ tests instead.

   * *note zipimport.zipimporter.load_module(): 311. is deprecated: use
     *note exec_module(): 312. instead.

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/issues/87999

   (2) https://github.com/python/cpython/issues/109218

   (3) https://github.com/python/cpython/issues/103636

   (4) https://github.com/python/cpython/issues/91760

   (5) https://github.com/python/cpython/issues/92332


File: python.info,  Node: C API Deprecations,  Prev: Pending Removal in Future Versions<5>,  Up: Deprecations

11.7 C API Deprecations
=======================

* Menu:

* Pending Removal in Python 3.14: Pending Removal in Python 3 14<6>.
* Pending Removal in Python 3.15: Pending Removal in Python 3 15<6>.
* Pending Removal in Future Versions: Pending Removal in Future Versions<6>.


File: python.info,  Node: Pending Removal in Python 3 14<6>,  Next: Pending Removal in Python 3 15<6>,  Up: C API Deprecations

11.7.1 Pending Removal in Python 3.14
-------------------------------------

   * The ‘ma_version_tag’ field in *note PyDictObject: 3c4. for
     extension modules ( PEP 699(1); gh-101193(2)).

   * Creating *note immutable types: 3c5. with mutable bases
     (gh-95388(3)).

   * Functions to configure Python’s initialization, deprecated in
     Python 3.11:

        * ‘PySys_SetArgvEx()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘PySys_SetArgv()’: Set *note PyConfig.argv: 3c6. instead.

        * ‘Py_SetProgramName()’: Set *note PyConfig.program_name: 3c7.
          instead.

        * ‘Py_SetPythonHome()’: Set *note PyConfig.home: 3be. instead.

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   * Global configuration variables:

        * *note Py_DebugFlag: 3c9.: Use *note PyConfig.parser_debug:
          3ca. instead.

        * *note Py_VerboseFlag: 3cb.: Use *note PyConfig.verbose: 3cc.
          instead.

        * *note Py_QuietFlag: 3cd.: Use *note PyConfig.quiet: 3ce.
          instead.

        * *note Py_InteractiveFlag: 3cf.: Use *note
          PyConfig.interactive: 3d0. instead.

        * *note Py_InspectFlag: 3d1.: Use *note PyConfig.inspect: 3d2.
          instead.

        * *note Py_OptimizeFlag: 3d3.: Use *note
          PyConfig.optimization_level: 3d4. instead.

        * *note Py_NoSiteFlag: 3d5.: Use *note PyConfig.site_import:
          3d6. instead.

        * *note Py_BytesWarningFlag: 3d7.: Use *note
          PyConfig.bytes_warning: 3d8. instead.

        * *note Py_FrozenFlag: 3d9.: Use *note
          PyConfig.pathconfig_warnings: 3da. instead.

        * *note Py_IgnoreEnvironmentFlag: 3db.: Use *note
          PyConfig.use_environment: 3dc. instead.

        * *note Py_DontWriteBytecodeFlag: 3dd.: Use *note
          PyConfig.write_bytecode: 3de. instead.

        * *note Py_NoUserSiteDirectory: 3df.: Use *note
          PyConfig.user_site_directory: 3e0. instead.

        * *note Py_UnbufferedStdioFlag: 3e1.: Use *note
          PyConfig.buffered_stdio: 3e2. instead.

        * *note Py_HashRandomizationFlag: 3e3.: Use *note
          PyConfig.use_hash_seed: 3e4. and *note PyConfig.hash_seed:
          3e5. instead.

        * *note Py_IsolatedFlag: 3e6.: Use *note PyConfig.isolated: 3e7.
          instead.

        * *note Py_LegacyWindowsFSEncodingFlag: 3e8.: Use *note
          PyPreConfig.legacy_windows_fs_encoding: 3e9. instead.

        * *note Py_LegacyWindowsStdioFlag: 3ea.: Use *note
          PyConfig.legacy_windows_stdio: 3a7. instead.

        * ‘Py_FileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_HasFileSystemDefaultEncoding’: Use *note
          PyConfig.filesystem_encoding: 3eb. instead.

        * ‘Py_FileSystemDefaultEncodeErrors’: Use *note
          PyConfig.filesystem_errors: 3ec. instead.

        * ‘Py_UTF8Mode’: Use *note PyPreConfig.utf8_mode: 3ed. instead.
          (see *note Py_PreInitialize(): 3ee.)

     The *note Py_InitializeFromConfig(): 3c8. API should be used with
     *note PyConfig: 3a9. instead.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0699/

   (2) https://github.com/python/cpython/issues/101193

   (3) https://github.com/python/cpython/issues/95388


File: python.info,  Node: Pending Removal in Python 3 15<6>,  Next: Pending Removal in Future Versions<6>,  Prev: Pending Removal in Python 3 14<6>,  Up: C API Deprecations

11.7.2 Pending Removal in Python 3.15
-------------------------------------

   * The *note PyImport_ImportModuleNoBlock(): 3c0.: Use *note
     PyImport_ImportModule(): 3c1. instead.

   * *note PyWeakref_GetObject(): 37c. and *note PyWeakref_GET_OBJECT():
     3c2.: Use *note PyWeakref_GetRef(): 37b. instead.

   * *note Py_UNICODE: 3f0. type and the ‘Py_UNICODE_WIDE’ macro: Use
     ‘wchar_t’ instead.

   * Python initialization functions:

        * *note PySys_ResetWarnOptions(): 3b2.: Clear *note
          sys.warnoptions: 3b3. and ‘warnings.filters’ instead.

        * *note Py_GetExecPrefix(): 3b4.: Get *note
          sys.base_exec_prefix: 3f1. and *note sys.exec_prefix: 3b5.
          instead.

        * *note Py_GetPath(): 3b6.: Get *note sys.path: 3b7. instead.

        * *note Py_GetPrefix(): 3b8.: Get *note sys.base_prefix: 3f2.
          and *note sys.prefix: 3b9. instead.

        * *note Py_GetProgramFullPath(): 3ba.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetProgramName(): 3bc.: Get *note sys.executable:
          3bb. instead.

        * *note Py_GetPythonHome(): 3bd.: Get *note PyConfig.home: 3be.
          or the *note PYTHONHOME: 3bf. environment variable instead.


File: python.info,  Node: Pending Removal in Future Versions<6>,  Prev: Pending Removal in Python 3 15<6>,  Up: C API Deprecations

11.7.3 Pending Removal in Future Versions
-----------------------------------------

The following APIs are deprecated and will be removed, although there is
currently no date scheduled for their removal.

   * *note Py_TPFLAGS_HAVE_FINALIZE: 3f5.: Unneeded since Python 3.8.

   * *note PyErr_Fetch(): 3f6.: Use *note PyErr_GetRaisedException():
     3f7. instead.

   * *note PyErr_NormalizeException(): 3f8.: Use *note
     PyErr_GetRaisedException(): 3f7. instead.

   * *note PyErr_Restore(): 3f9.: Use *note PyErr_SetRaisedException():
     3fa. instead.

   * *note PyModule_GetFilename(): 3fb.: Use *note
     PyModule_GetFilenameObject(): 3fc. instead.

   * *note PyOS_AfterFork(): 3fd.: Use *note PyOS_AfterFork_Child():
     3fe. instead.

   * *note PySlice_GetIndicesEx(): 3ff.: Use *note PySlice_Unpack():
     400. and *note PySlice_AdjustIndices(): 401. instead.

   * ‘PyUnicode_AsDecodedObject()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsDecodedUnicode()’: Use *note PyCodec_Decode(): 402.
     instead.

   * ‘PyUnicode_AsEncodedObject()’: Use *note PyCodec_Encode(): 403.
     instead.

   * ‘PyUnicode_AsEncodedUnicode()’: Use *note PyCodec_Encode(): 403.
     instead.

   * *note PyUnicode_READY(): 404.: Unneeded since Python 3.12

   * ‘PyErr_Display()’: Use *note PyErr_DisplayException(): 405.
     instead.

   * ‘_PyErr_ChainExceptions()’: Use ‘_PyErr_ChainExceptions1()’
     instead.

   * ‘PyBytesObject.ob_shash’ member: call *note PyObject_Hash(): 406.
     instead.

   * ‘PyDictObject.ma_version_tag’ member.

   * Thread Local Storage (TLS) API:

        * *note PyThread_create_key(): 407.: Use *note
          PyThread_tss_alloc(): 408. instead.

        * *note PyThread_delete_key(): 409.: Use *note
          PyThread_tss_free(): 40a. instead.

        * *note PyThread_set_key_value(): 40b.: Use *note
          PyThread_tss_set(): 40c. instead.

        * *note PyThread_get_key_value(): 40d.: Use *note
          PyThread_tss_get(): 40e. instead.

        * *note PyThread_delete_key_value(): 40f.: Use *note
          PyThread_tss_delete(): 410. instead.

        * *note PyThread_ReInitTLS(): 411.: Unneeded since Python 3.7.


File: python.info,  Node: Glossary,  Next: About this documentation,  Prev: Deprecations,  Up: Top

12 Glossary
***********

‘>>>’

     The default Python prompt of the *note interactive: 169. shell.
     Often seen for code examples which can be executed interactively in
     the interpreter.

‘...’

     Can refer to:

        * The default Python prompt of the *note interactive: 169. shell
          when entering the code for an indented code block, when within
          a pair of matching left and right delimiters (parentheses,
          square brackets, curly braces or triple quotes), or after
          specifying a decorator.

        * The three dots form of the *note Ellipsis: 1db2. object.

abstract base class

     Abstract base classes complement *note duck-typing: 5607. by
     providing a way to define interfaces when other techniques like
     *note hasattr(): 4d5. would be clumsy or subtly wrong (for example
     with *note magic methods: 2117.).  ABCs introduce virtual
     subclasses, which are classes that don’t inherit from a class but
     are still recognized by *note isinstance(): 445. and *note
     issubclass(): 7c5.; see the *note abc: 4. module documentation.
     Python comes with many built-in ABCs for data structures (in the
     *note collections.abc: 1e. module), numbers (in the *note numbers:
     9e. module), streams (in the *note io: 7f. module), import finders
     and loaders (in the *note importlib.abc: 78. module).  You can
     create your own ABCs with the ‘abc’ module.

annotation

     A label associated with a variable, a class attribute or a function
     parameter or return value, used by convention as a *note type hint:
     2131.

     Annotations of local variables cannot be accessed at runtime, but
     annotations of global variables, class attributes, and functions
     are stored in the ‘__annotations__’ special attribute of modules,
     classes, and functions, respectively.

     See *note variable annotation: d7f, *note function annotation:
     1dcf, PEP 484(1) and PEP 526(2), which describe this functionality.
     Also see *note Annotations Best Practices: 7dd. for best practices
     on working with annotations.

argument

     A value passed to a *note function: 220d. (or *note method: 1657.)
     when calling the function.  There are two kinds of argument:

        * 'keyword argument': an argument preceded by an identifier
          (e.g.  ‘name=’) in a function call or passed as a value in a
          dictionary preceded by ‘**’.  For example, ‘3’ and ‘5’ are
          both keyword arguments in the following calls to *note
          complex(): 2f8.:

               complex(real=3, imag=5)
               complex(**{'real': 3, 'imag': 5})

        * 'positional argument': an argument that is not a keyword
          argument.  Positional arguments can appear at the beginning of
          an argument list and/or be passed as elements of an *note
          iterable: 126d. preceded by ‘*’.  For example, ‘3’ and ‘5’ are
          both positional arguments in the following calls:

               complex(3, 5)
               complex(*(3, 5))

     Arguments are assigned to the named local variables in a function
     body.  See the *note Calls: dab. section for the rules governing
     this assignment.  Syntactically, any expression can be used to
     represent an argument; the evaluated value is assigned to the local
     variable.

     See also the *note parameter: 20ae. glossary entry, the FAQ
     question on *note the difference between arguments and parameters:
     5541, and PEP 362(3).

asynchronous context manager

     An object which controls the environment seen in an *note async
     with: 5d8. statement by defining *note __aenter__(): 2181. and
     *note __aexit__(): 1734. methods.  Introduced by PEP 492(4).

asynchronous generator

     A function which returns an *note asynchronous generator iterator:
     361f.  It looks like a coroutine function defined with *note async
     def: 5d4. except that it contains *note yield: 9d8. expressions for
     producing a series of values usable in an *note async for: ac0.
     loop.

     Usually refers to an asynchronous generator function, but may refer
     to an 'asynchronous generator iterator' in some contexts.  In cases
     where the intended meaning isn’t clear, using the full terms avoids
     ambiguity.

     An asynchronous generator function may contain *note await: 1b9.
     expressions as well as *note async for: ac0, and *note async with:
     5d8. statements.

asynchronous generator iterator

     An object created by an *note asynchronous generator: 21f2.
     function.

     This is an *note asynchronous iterator: 1ab. which when called
     using the *note __anext__(): 1678. method returns an awaitable
     object which will execute the body of the asynchronous generator
     function until the next *note yield: 9d8. expression.

     Each *note yield: 9d8. temporarily suspends processing, remembering
     the execution state (including local variables and pending
     try-statements).  When the 'asynchronous generator iterator'
     effectively resumes with another awaitable returned by *note
     __anext__(): 1678, it picks up where it left off.  See PEP 492(5)
     and PEP 525(6).

asynchronous iterable

     An object, that can be used in an *note async for: ac0. statement.
     Must return an *note asynchronous iterator: 1ab. from its *note
     __aiter__(): c1c. method.  Introduced by PEP 492(7).

asynchronous iterator

     An object that implements the *note __aiter__(): c1c. and *note
     __anext__(): 1678. methods.  ‘__anext__()’ must return an *note
     awaitable: 1ad. object.  *note async for: ac0. resolves the
     awaitables returned by an asynchronous iterator’s ‘__anext__()’
     method until it raises a *note StopAsyncIteration: 1bbe. exception.
     Introduced by PEP 492(8).

atomic operation

     An operation that appears to execute as a single, indivisible step:
     no other thread can observe it half-done, and its effects become
     visible all at once.  Python does not guarantee that high-level
     statements are atomic (for example, ‘x += 1’ performs multiple
     bytecode operations and is not atomic).  Atomicity is only
     guaranteed where explicitly documented.  See also *note race
     condition: 5609. and *note data race: 560a.

attribute

     A value associated with an object which is usually referenced by
     name using dotted expressions.  For example, if an object 'o' has
     an attribute 'a' it would be referenced as 'o.a'.

     It is possible to give an object an attribute whose name is not an
     identifier as defined by *note Identifiers and keywords: 2040, for
     example using *note setattr(): 2316, if the object allows it.  Such
     an attribute will not be accessible using a dotted expression, and
     would instead need to be retrieved with *note getattr(): bf0.

awaitable

     An object that can be used in an *note await: 1b9. expression.  Can
     be a *note coroutine: 494. or an object with an *note __await__():
     da3. method.  See also PEP 492(9).

BDFL

     Benevolent Dictator For Life, a.k.a.  Guido van Rossum(10),
     Python’s creator.

binary file

     A *note file object: 1208. able to read and write *note bytes-like
     objects: d55.  Examples of binary files are files opened in binary
     mode (‘'rb'’, ‘'wb'’ or ‘'rb+'’), *note sys.stdin.buffer: 540,
     *note sys.stdout.buffer: aec, and instances of *note io.BytesIO:
     ed8. and *note gzip.GzipFile: 41d.

     See also *note text file: 1e25. for a file object able to read and
     write *note str: 44f. objects.

borrowed reference

     In Python’s C API, a borrowed reference is a reference to an
     object, where the code using the object does not own the reference.
     It becomes a dangling pointer if the object is destroyed.  For
     example, a garbage collection can remove the last *note strong
     reference: 33e. to the object and so destroy it.

     Calling *note Py_INCREF(): 571. on the *note borrowed reference:
     33f. is recommended to convert it to a *note strong reference: 33e.
     in-place, except when the object cannot be destroyed before the
     last usage of the borrowed reference.  The *note Py_NewRef(): 8a1.
     function can be used to create a new strong reference.

bytes-like object

     An object that supports the *note Buffer Protocol: 2e8. and can
     export a C-*note contiguous: 23dc. buffer.  This includes all *note
     bytes: 1c2, *note bytearray: 2ea, and *note array.array: 1a0.
     objects, as well as many common *note memoryview: 2eb. objects.
     Bytes-like objects can be used for various operations that work
     with binary data; these include compression, saving to a binary
     file, and sending over a socket.

     Some operations need the binary data to be mutable.  The
     documentation often refers to these as “read-write bytes-like
     objects”.  Example mutable buffer objects include *note bytearray:
     2ea. and a *note memoryview: 2eb. of a ‘bytearray’.  Other
     operations require the binary data to be stored in immutable
     objects (“read-only bytes-like objects”); examples of these include
     *note bytes: 1c2. and a ‘memoryview’ of a ‘bytes’ object.

bytecode

     Python source code is compiled into bytecode, the internal
     representation of a Python program in the CPython interpreter.  The
     bytecode is also cached in ‘.pyc’ files so that executing the same
     file is faster the second time (recompilation from source to
     bytecode can be avoided).  This “intermediate language” is said to
     run on a *note virtual machine: 372b. that executes the machine
     code corresponding to each bytecode.  Do note that bytecodes are
     not expected to work between different Python virtual machines, nor
     to be stable between Python releases.

     A list of bytecode instructions can be found in the documentation
     for *note the dis module: 5b5.

callable

     A callable is an object that can be called, possibly with a set of
     arguments (see *note argument: 44c.), with the following syntax:

          callable(argument1, argument2, argumentN)

     A *note function: 220d, and by extension a *note method: 1657, is a
     callable.  An instance of a class that implements the *note
     __call__(): 55b. method is also a callable.

callback

     A subroutine function which is passed as an argument to be executed
     at some point in the future.

class

     A template for creating user-defined objects.  Class definitions
     normally contain method definitions which operate on instances of
     the class.

class variable

     A variable defined in a class and intended to be modified only at
     class level (i.e., not in an instance of the class).

closure variable

     A *note free variable: 218c. referenced from a *note nested scope:
     20f3. that is defined in an outer scope rather than being resolved
     at runtime from the globals or builtin namespaces.  May be
     explicitly defined with the *note nonlocal: 12ef. keyword to allow
     write access, or implicitly defined if the variable is only being
     read.

     For example, in the ‘inner’ function in the following code, both
     ‘x’ and ‘print’ are *note free variables: 218c, but only ‘x’ is a
     'closure variable':

          def outer():
              x = 0
              def inner():
                  nonlocal x
                  x += 1
                  print(x)
              return inner

     Due to the *note codeobject.co_freevars: 20aa. attribute (which,
     despite its name, only includes the names of closure variables
     rather than listing all referenced free variables), the more
     general *note free variable: 218c. term is sometimes used even when
     the intended meaning is to refer specifically to closure variables.

complex number

     An extension of the familiar real number system in which all
     numbers are expressed as a sum of a real part and an imaginary
     part.  Imaginary numbers are real multiples of the imaginary unit
     (the square root of ‘-1’), often written ‘i’ in mathematics or ‘j’
     in engineering.  Python has built-in support for complex numbers,
     which are written with this latter notation; the imaginary part is
     written with a ‘j’ suffix, e.g., ‘3+1j’.  To get access to complex
     equivalents of the *note math: 8e. module, use *note cmath: 18.
     Use of complex numbers is a fairly advanced mathematical feature.
     If you’re not aware of a need for them, it’s almost certain you can
     safely ignore them.

concurrency

     The ability of a computer program to perform multiple tasks at the
     same time.  Python provides libraries for writing programs that
     make use of different forms of concurrency.  *note asyncio: a. is a
     library for dealing with asynchronous tasks and coroutines.  *note
     threading: ed. provides access to operating system threads and
     *note multiprocessing: 94. to operating system processes.
     Multi-core processors can execute threads and processes on
     different CPU cores at the same time (see *note parallelism:
     560f.).

concurrent modification

     When multiple threads modify shared data at the same time.
     Concurrent modification without proper synchronization can cause
     *note race conditions: 5609, and might also trigger a *note data
     race: 560a, data corruption, or both.

context

     This term has different meanings depending on where and how it is
     used.  Some common meanings:

        * The temporary state or environment established by a *note
          context manager: 5d7. via a *note with: 5d5. statement.

        * The collection of key­value bindings associated with a
          particular *note contextvars.Context: 15dd. object and
          accessed via *note ContextVar: 1662. objects.  Also see *note
          context variable: 5611.

        * A *note contextvars.Context: 15dd. object.  Also see *note
          current context: 16b5.

context management protocol

     The *note __enter__(): 5cb. and *note __exit__(): 1349. methods
     called by the *note with: 5d5. statement.  See PEP 343(11).

context manager

     An object which implements the *note context management protocol:
     16b6. and controls the environment seen in a *note with: 5d5.
     statement.  See PEP 343(12).

context variable

     A variable whose value depends on which context is the *note
     current context: 16b5.  Values are accessed via *note
     contextvars.ContextVar: 1662. objects.  Context variables are
     primarily used to isolate state between concurrent asynchronous
     tasks.

contiguous

     A buffer is considered contiguous exactly if it is either
     'C-contiguous' or 'Fortran contiguous'.  Zero-dimensional buffers
     are C and Fortran contiguous.  In one-dimensional arrays, the items
     must be laid out in memory next to each other, in order of
     increasing indexes starting from zero.  In multidimensional
     C-contiguous arrays, the last index varies the fastest when
     visiting items in order of memory address.  However, in Fortran
     contiguous arrays, the first index varies the fastest.

coroutine

     Coroutines are a more generalized form of subroutines.  Subroutines
     are entered at one point and exited at another point.  Coroutines
     can be entered, exited, and resumed at many different points.  They
     can be implemented with the *note async def: 5d4. statement.  See
     also PEP 492(13).

coroutine function

     A function which returns a *note coroutine: 494. object.  A
     coroutine function may be defined with the *note async def: 5d4.
     statement, and may contain *note await: 1b9, *note async for: ac0,
     and *note async with: 5d8. keywords.  These were introduced by PEP
     492(14).

CPython

     The canonical implementation of the Python programming language, as
     distributed on python.org(15).  The term “CPython” is used when
     necessary to distinguish this implementation from others such as
     Jython or IronPython.

current context

     The *note context: 16b4. (*note contextvars.Context: 15dd. object)
     that is currently used by *note ContextVar: 1662. objects to access
     (get or set) the values of *note context variables: 5611.  Each
     thread has its own current context.  Frameworks for executing
     asynchronous tasks (see *note asyncio: a.) associate each task with
     a context which becomes the current context whenever the task
     starts or resumes execution.

data race

     A situation where multiple threads access the same memory location
     concurrently, at least one of the accesses is a write, and the
     threads do not use any synchronization to control their access.
     Data races lead to *note non-deterministic: 5612. behavior and can
     cause data corruption.  Proper use of *note locks: 5613. and other
     *note synchronization primitives: 5614. prevents data races.  Note
     that data races can only happen in native code, but that *note
     native code: 5615. might be exposed in a Python API. See also *note
     race condition: 5609. and *note thread-safe: 5616.

deadlock

     A situation in which two or more tasks (threads, processes, or
     coroutines) wait indefinitely for each other to release resources
     or complete actions, preventing any from making progress.  For
     example, if thread A holds lock 1 and waits for lock 2, while
     thread B holds lock 2 and waits for lock 1, both threads will wait
     indefinitely.  In Python this often arises from acquiring multiple
     locks in conflicting orders or from circular join/await
     dependencies.  Deadlocks can be avoided by always acquiring
     multiple *note locks: 5613. in a consistent order.  See also lock
     and *note reentrant: 5618.

decorator

     A function returning another function, usually applied as a
     function transformation using the ‘@wrapper’ syntax.  Common
     examples for decorators are *note classmethod(): 166. and *note
     staticmethod(): 419.

     The decorator syntax is merely syntactic sugar, the following two
     function definitions are semantically equivalent:

          def f(arg):
              ...
          f = staticmethod(f)

          @staticmethod
          def f(arg):
              ...

     The same concept exists for classes, but is less commonly used
     there.  See the documentation for *note function definitions: 1dce.
     and *note class definitions: 131f. for more about decorators.

descriptor

     Any object which defines the methods *note __get__(): 1537, *note
     __set__(): 211b, or *note __delete__(): 1713.  When a class
     attribute is a descriptor, its special binding behavior is
     triggered upon attribute lookup.  Normally, using 'a.b' to get, set
     or delete an attribute looks up the object named 'b' in the class
     dictionary for 'a', but if 'b' is a descriptor, the respective
     descriptor method gets called.  Understanding descriptors is a key
     to a deep understanding of Python because they are the basis for
     many features including functions, methods, properties, class
     methods, static methods, and reference to super classes.

     For more information about descriptors’ methods, see *note
     Implementing Descriptors: c70. or the *note Descriptor How To
     Guide: 153c.

dictionary

     An associative array, where arbitrary keys are mapped to values.
     The keys can be any object with *note __hash__(): b14. and *note
     __eq__(): b13. methods.  Called a hash in Perl.

dictionary comprehension

     A compact way to process all or part of the elements in an iterable
     and return a dictionary with the results.  ‘results = {n: n ** 2
     for n in range(10)}’ generates a dictionary containing key ‘n’
     mapped to value ‘n ** 2’.  See *note Displays for lists, sets and
     dictionaries: 5d3.

dictionary view

     The objects returned from *note dict.keys(): 7d1, *note
     dict.values(): 7d2, and *note dict.items(): 7d3. are called
     dictionary views.  They provide a dynamic view on the dictionary’s
     entries, which means that when the dictionary changes, the view
     reflects these changes.  To force the dictionary view to become a
     full list use ‘list(dictview)’.  See *note Dictionary view objects:
     23fb.

docstring

     A string literal which appears as the first expression in a class,
     function or module.  While ignored when the suite is executed, it
     is recognized by the compiler and put into the *note __doc__: 931.
     attribute of the enclosing class, function or module.  Since it is
     available via introspection, it is the canonical place for
     documentation of the object.

duck-typing

     A programming style which does not look at an object’s type to
     determine if it has the right interface; instead, the method or
     attribute is simply called or used (“If it looks like a duck and
     quacks like a duck, it must be a duck.”) By emphasizing interfaces
     rather than specific types, well-designed code improves its
     flexibility by allowing polymorphic substitution.  Duck-typing
     avoids tests using *note type(): d71. or *note isinstance(): 445.
     (Note, however, that duck-typing can be complemented with *note
     abstract base classes: 11fa.)  Instead, it typically employs *note
     hasattr(): 4d5. tests or *note EAFP: 2d77. programming.

dunder

     An informal short-hand for “double underscore”, used when talking
     about a *note special method: 1a06.  For example, ‘__init__’ is
     often pronounced “dunder init”.

EAFP

     Easier to ask for forgiveness than permission.  This common Python
     coding style assumes the existence of valid keys or attributes and
     catches exceptions if the assumption proves false.  This clean and
     fast style is characterized by the presence of many *note try: 6ec.
     and *note except: 18b. statements.  The technique contrasts with
     the *note LBYL: 561b. style common to many other languages such as
     C.

expression

     A piece of syntax which can be evaluated to some value.  In other
     words, an expression is an accumulation of expression elements like
     literals, names, attribute access, operators or function calls
     which all return a value.  In contrast to many other languages, not
     all language constructs are expressions.  There are also *note
     statement: 2951.s which cannot be used as expressions, such as
     *note while: 1d9a.  Assignments are also statements, not
     expressions.

extension module

     A module written in C or C++, using Python’s C API to interact with
     the core and with user code.

f-string

     String literals prefixed with ‘'f'’ or ‘'F'’ are commonly called
     “f-strings” which is short for *note formatted string literals:
     9b4.  See also PEP 498(16).

file object

     An object exposing a file-oriented API (with methods such as
     ‘read()’ or ‘write()’) to an underlying resource.  Depending on the
     way it was created, a file object can mediate access to a real
     on-disk file or to another type of storage or communication device
     (for example standard input/output, in-memory buffers, sockets,
     pipes, etc.).  File objects are also called 'file-like objects' or
     'streams'.

     There are actually three categories of file objects: raw *note
     binary files: 1e26, buffered binary files and *note text files:
     1e25.  Their interfaces are defined in the *note io: 7f. module.
     The canonical way to create a file object is by using the *note
     open(): 51f. function.

file-like object

     A synonym for *note file object: 1208.

filesystem encoding and error handler

     Encoding and error handler used by Python to decode bytes from the
     operating system and encode Unicode to the operating system.

     The filesystem encoding must guarantee to successfully decode all
     bytes below 128.  If the file system encoding fails to provide this
     guarantee, API functions can raise *note UnicodeError: 12eb.

     The *note sys.getfilesystemencoding(): c7a. and *note
     sys.getfilesystemencodeerrors(): d0d. functions can be used to get
     the filesystem encoding and error handler.

     The *note filesystem encoding and error handler: 53e. are
     configured at Python startup by the *note PyConfig_Read(): 793.
     function: see *note filesystem_encoding: 3eb. and *note
     filesystem_errors: 3ec. members of *note PyConfig: 3a9.

     See also the *note locale encoding: 242.

finder

     An object that tries to find the *note loader: 17c1. for a module
     that is being imported.

     There are two types of finder: *note meta path finders: 10ae. for
     use with *note sys.meta_path: d53, and *note path entry finders:
     10af. for use with *note sys.path_hooks: 105f.

     See *note Finders and loaders: 21a6. and *note importlib: 77. for
     much more detail.

floor division

     Mathematical division that rounds down to nearest integer.  The
     floor division operator is ‘//’.  For example, the expression ‘11
     // 4’ evaluates to ‘2’ in contrast to the ‘2.75’ returned by float
     true division.  Note that ‘(-11) // 4’ is ‘-3’ because that is
     ‘-2.75’ rounded 'downward'.  See PEP 238(17).

free threading

     A threading model where multiple threads can run Python bytecode
     simultaneously within the same interpreter.  This is in contrast to
     the *note global interpreter lock: 148. which allows only one
     thread to execute Python bytecode at a time.  See PEP 703(18).

free variable

     Formally, as defined in the *note language execution model: 2189, a
     free variable is any variable used in a namespace which is not a
     local variable in that namespace.  See *note closure variable:
     20f4. for an example.  Pragmatically, due to the name of the *note
     codeobject.co_freevars: 20aa. attribute, the term is also sometimes
     used as a synonym for closure variable.

function

     A series of statements which returns some value to a caller.  It
     can also be passed zero or more *note arguments: 44c. which may be
     used in the execution of the body.  See also *note parameter: 20ae,
     *note method: 1657, and the *note Function definitions: 1dce.
     section.

function annotation

     An *note annotation: 45b. of a function parameter or return value.

     Function annotations are usually used for *note type hints: 2131.:
     for example, this function is expected to take two *note int: 257.
     arguments and is also expected to have an ‘int’ return value:

          def sum_two_numbers(a: int, b: int) -> int:
             return a + b

     Function annotation syntax is explained in section *note Function
     definitions: 1dce.

     See *note variable annotation: d7f. and PEP 484(19), which describe
     this functionality.  Also see *note Annotations Best Practices:
     7dd. for best practices on working with annotations.

__future__

     A *note future statement: 189, ‘from __future__ import <feature>’,
     directs the compiler to compile the current module using syntax or
     semantics that will become standard in a future release of Python.
     The *note __future__: 0. module documents the possible values of
     'feature'.  By importing this module and evaluating its variables,
     you can see when a new feature was first added to the language and
     when it will (or did) become the default:

          >>> import __future__
          >>> __future__.division
          _Feature((2, 2, 0, 'alpha', 2), (3, 0, 0, 'alpha', 0), 8192)

garbage collection

     The process of freeing memory when it is not used anymore.  Python
     performs garbage collection via reference counting and a cyclic
     garbage collector that is able to detect and break reference
     cycles.  The garbage collector can be controlled using the *note
     gc: 60. module.

generator

     A function which returns a *note generator iterator: bff.  It looks
     like a normal function except that it contains *note yield: 9d8.
     expressions for producing a series of values usable in a for-loop
     or that can be retrieved one at a time with the *note next(): 7dc.
     function.

     Usually refers to a generator function, but may refer to a
     'generator iterator' in some contexts.  In cases where the intended
     meaning isn’t clear, using the full terms avoids ambiguity.

generator iterator

     An object created by a *note generator: 109f. function.

     Each *note yield: 9d8. temporarily suspends processing, remembering
     the execution state (including local variables and pending
     try-statements).  When the 'generator iterator' resumes, it picks
     up where it left off (in contrast to functions which start fresh on
     every invocation).

generator expression

     An *note expression: 2135. that returns an *note iterator: 1ac.  It
     looks like a normal expression followed by a ‘for’ clause defining
     a loop variable, range, and an optional ‘if’ clause.  The combined
     expression generates values for an enclosing function:

          >>> sum(i*i for i in range(10))         # sum of squares 0, 1, 4, ... 81
          285

generic function

     A function composed of multiple functions implementing the same
     operation for different types.  Which implementation should be used
     during a call is determined by the dispatch algorithm.

     See also the *note single dispatch: 9fd. glossary entry, the *note
     functools.singledispatch(): 63c. decorator, and PEP 443(20).

generic type

     A *note type: 1aa5. that can be parameterized; typically a *note
     container class: 213a. such as *note list: 614. or *note dict: 256.
     Used for *note type hints: 2131. and *note annotations: 45b.

     For more details, see *note generic alias types: 6b5, PEP 483(21),
     PEP 484(22), PEP 585(23), and the *note typing: 104. module.

GIL

     See *note global interpreter lock: 148.

global interpreter lock

     The mechanism used by the *note CPython: 6f9. interpreter to assure
     that only one thread executes Python *note bytecode: 187. at a
     time.  This simplifies the CPython implementation by making the
     object model (including critical built-in types such as *note dict:
     256.) implicitly safe against concurrent access.  Locking the
     entire interpreter makes it easier for the interpreter to be
     multi-threaded, at the expense of much of the parallelism afforded
     by multi-processor machines.

     However, some extension modules, either standard or third-party,
     are designed so as to release the GIL when doing computationally
     intensive tasks such as compression or hashing.  Also, the GIL is
     always released when doing I/O.

     As of Python 3.13, the GIL can be disabled using the *note
     -disable-gil: 174. build configuration.  After building Python with
     this option, code must be run with *note -X gil=0: 176. or after
     setting the *note PYTHON_GIL=0: 175. environment variable.  This
     feature enables improved performance for multi-threaded
     applications and makes it easier to use multi-core CPUs
     efficiently.  For more details, see PEP 703(24).

global state

     Data that is accessible throughout a program, such as module-level
     variables, class variables, or C static variables in *note
     extension modules: 480c.  In multi-threaded programs, global state
     shared between threads typically requires synchronization to avoid
     *note race conditions: 5609. and *note data races: 560a.

hash-based pyc

     A bytecode cache file that uses the hash rather than the
     last-modified time of the corresponding source file to determine
     its validity.  See *note Cached bytecode invalidation: 5ef.

hashable

     An object is 'hashable' if it has a hash value which never changes
     during its lifetime (it needs a *note __hash__(): b14. method), and
     can be compared to other objects (it needs an *note __eq__(): b13.
     method).  Hashable objects which compare equal must have the same
     hash value.

     Hashability makes an object usable as a dictionary key and a set
     member, because these data structures use the hash value
     internally.

     Most of Python’s immutable built-in objects are hashable; mutable
     containers (such as lists or dictionaries) are not; immutable
     containers (such as tuples and frozensets) are only hashable if
     their elements are hashable.  Objects which are instances of
     user-defined classes are hashable by default.  They all compare
     unequal (except with themselves), and their hash value is derived
     from their *note id(): 1471.

IDLE

     An Integrated Development and Learning Environment for Python.
     *note IDLE — Python editor and shell: 1050. is a basic editor and
     interpreter environment which ships with the standard distribution
     of Python.

immortal

     'Immortal objects' are a CPython implementation detail introduced
     in PEP 683(25).

     If an object is immortal, its *note reference count: 4b94. is never
     modified, and therefore it is never deallocated while the
     interpreter is running.  For example, *note True: c2d. and *note
     None: 678. are immortal in CPython.

immutable

     An object with a fixed value.  Immutable objects include numbers,
     strings and tuples.  Such an object cannot be altered.  A new
     object has to be created if a different value has to be stored.
     They play an important role in places where a constant hash value
     is needed, for example as a key in a dictionary.  Immutable objects
     are inherently *note thread-safe: 5616. because their state cannot
     be modified after creation, eliminating concerns about improperly
     synchronized *note concurrent modification: 5610.

import path

     A list of locations (or *note path entries: 21b7.) that are
     searched by the *note path based finder: 21ac. for modules to
     import.  During import, this list of locations usually comes from
     *note sys.path: 3b7, but for subpackages it may also come from the
     parent package’s ‘__path__’ attribute.

importing

     The process by which Python code in one module is made available to
     Python code in another module.

importer

     An object that both finds and loads a module; both a *note finder:
     20cd. and *note loader: 17c1. object.

interactive

     Python has an interactive interpreter which means you can enter
     statements and expressions at the interpreter prompt, immediately
     execute them and see their results.  Just launch ‘python’ with no
     arguments (possibly by selecting it from your computer’s main
     menu).  It is a very powerful way to test out new ideas or inspect
     modules and packages (remember ‘help(x)’).  For more on interactive
     mode, see *note Interactive Mode: 16f.

interpreted

     Python is an interpreted language, as opposed to a compiled one,
     though the distinction can be blurry because of the presence of the
     bytecode compiler.  This means that source files can be run
     directly without explicitly creating an executable which is then
     run.  Interpreted languages typically have a shorter
     development/debug cycle than compiled ones, though their programs
     generally also run more slowly.  See also *note interactive: 169.

interpreter shutdown

     When asked to shut down, the Python interpreter enters a special
     phase where it gradually releases all allocated resources, such as
     modules and various critical internal structures.  It also makes
     several calls to the *note garbage collector: 1a83.  This can
     trigger the execution of code in user-defined destructors or
     weakref callbacks.  Code executed during the shutdown phase can
     encounter various exceptions as the resources it relies on may not
     function anymore (common examples are library modules or the
     warnings machinery).

     The main reason for interpreter shutdown is that the ‘__main__’
     module or the script being run has finished executing.

iterable

     An object capable of returning its members one at a time.  Examples
     of iterables include all sequence types (such as *note list: 614,
     *note str: 44f, and *note tuple: 373.) and some non-sequence types
     like *note dict: 256, *note file objects: 1208, and objects of any
     classes you define with an *note __iter__(): c90. method or with a
     *note __getitem__(): 283. method that implements *note sequence:
     4f4. semantics.

     Iterables can be used in a *note for: 2f2. loop and in many other
     places where a sequence is needed (*note zip(): 7d4, *note map():
     86a, …).  When an iterable object is passed as an argument to the
     built-in function *note iter(): 7db, it returns an iterator for the
     object.  This iterator is good for one pass over the set of values.
     When using iterables, it is usually not necessary to call ‘iter()’
     or deal with iterator objects yourself.  The ‘for’ statement does
     that automatically for you, creating a temporary unnamed variable
     to hold the iterator for the duration of the loop.  See also *note
     iterator: 1ac, *note sequence: 4f4, and *note generator: 109f.

iterator

     An object representing a stream of data.  Repeated calls to the
     iterator’s *note __next__(): 1315. method (or passing it to the
     built-in function *note next(): 7dc.) return successive items in
     the stream.  When no more data are available a *note StopIteration:
     c1b. exception is raised instead.  At this point, the iterator
     object is exhausted and any further calls to its ‘__next__()’
     method just raise ‘StopIteration’ again.  Iterators are required to
     have an *note __iter__(): 1e65. method that returns the iterator
     object itself so every iterator is also iterable and may be used in
     most places where other iterables are accepted.  One notable
     exception is code which attempts multiple iteration passes.  A
     container object (such as a *note list: 614.) produces a fresh new
     iterator each time you pass it to the *note iter(): 7db. function
     or use it in a *note for: 2f2. loop.  Attempting this with an
     iterator will just return the same exhausted iterator object used
     in the previous iteration pass, making it appear like an empty
     container.

     More information can be found in *note Iterator Types: 232f.

     'CPython implementation detail:' CPython does not consistently
     apply the requirement that an iterator define *note __iter__():
     1e65.  And also please note that *note free-threaded: 15b3. CPython
     does not guarantee *note thread-safe: 5616. behavior of iterator
     operations.

key function

     A key function or collation function is a callable that returns a
     value used for sorting or ordering.  For example, *note
     locale.strxfrm(): 1614. is used to produce a sort key that is aware
     of locale specific sort conventions.

     A number of tools in Python accept key functions to control how
     elements are ordered or grouped.  They include *note min(): f3f,
     *note max(): f40, *note sorted(): bed, *note list.sort(): bee,
     *note heapq.merge(): e36, *note heapq.nsmallest(): 26f4, *note
     heapq.nlargest(): 26f3, and *note itertools.groupby(): 15aa.

     There are several ways to create a key function.  For example.  the
     *note str.casefold(): e06. method can serve as a key function for
     case insensitive sorts.  Alternatively, a key function can be built
     from a *note lambda: 12e4. expression such as ‘lambda r: (r[0],
     r[2])’.  Also, *note operator.attrgetter(): e66, *note
     operator.itemgetter(): a70, and *note operator.methodcaller(): e67.
     are three key function constructors.  See the *note Sorting HOW TO:
     2337. for examples of how to create and use key functions.

keyword argument

     See *note argument: 44c.

lambda

     An anonymous inline function consisting of a single *note
     expression: 2135. which is evaluated when the function is called.
     The syntax to create a lambda function is ‘lambda [parameters]:
     expression’

LBYL

     Look before you leap.  This coding style explicitly tests for
     pre-conditions before making calls or lookups.  This style
     contrasts with the *note EAFP: 2d77. approach and is characterized
     by the presence of many *note if: 2f3. statements.

     In a multi-threaded environment, the LBYL approach can risk
     introducing a *note race condition: 5609. between “the looking” and
     “the leaping”.  For example, the code, ‘if key in mapping: return
     mapping[key]’ can fail if another thread removes 'key' from
     'mapping' after the test, but before the lookup.  This issue can be
     solved with *note locks: 5613. or by using the *note EAFP: 2d77.
     approach.  See also *note thread-safe: 5616.

lexical analyzer

     Formal name for the 'tokenizer'; see *note token: 2029.

list

     A built-in Python *note sequence: 4f4.  Despite its name it is more
     akin to an array in other languages than to a linked list since
     access to elements is 'O'(1).

list comprehension

     A compact way to process all or part of the elements in a sequence
     and return a list with the results.  ‘result = ['{:#04x}'.format(x)
     for x in range(256) if x % 2 == 0]’ generates a list of strings
     containing even hex numbers (0x..)  in the range from 0 to 255.
     The *note if: 2f3. clause is optional.  If omitted, all elements in
     ‘range(256)’ are processed.

lock

     A *note synchronization primitive: 5614. that allows only one
     thread at a time to access a shared resource.  A thread must
     acquire a lock before accessing the protected resource and release
     it afterward.  If a thread attempts to acquire a lock that is
     already held by another thread, it will block until the lock
     becomes available.  Python’s *note threading: ed. module provides
     *note Lock: 178a. (a basic lock) and *note RLock: 2de. (a *note
     reentrant: 5618. lock).  Locks are used to prevent *note race
     conditions: 5609. and ensure *note thread-safe: 5616. access to
     shared data.  Alternative design patterns to locks exist such as
     queues, producer/consumer patterns, and thread-local state.  See
     also *note deadlock: 5617, and reentrant.

lock-free

     An operation that does not acquire any *note lock: 5613. and uses
     atomic CPU instructions to ensure correctness.  Lock-free
     operations can execute concurrently without blocking each other and
     cannot be blocked by operations that hold locks.  In *note
     free-threaded: 15b3. Python, built-in types like *note dict: 256.
     and *note list: 614. provide lock-free read operations, which means
     other threads may observe intermediate states during multi-step
     modifications even when those modifications hold the *note
     per-object lock: 5624.

loader

     An object that loads a module.  It must define the ‘exec_module()’
     and ‘create_module()’ methods to implement the *note Loader: efb.
     interface.  A loader is typically returned by a *note finder: 20cd.
     See also:

        * *note Finders and loaders: 21a6.

        * *note importlib.abc.Loader: efb.

        * PEP 302(26)

locale encoding

     On Unix, it is the encoding of the LC_CTYPE locale.  It can be set
     with *note locale.setlocale(locale.LC_CTYPE, new_locale): 2db.

     On Windows, it is the ANSI code page (ex: ‘"cp1252"’).

     On Android and VxWorks, Python uses ‘"utf-8"’ as the locale
     encoding.

     *note locale.getencoding(): 2dc. can be used to get the locale
     encoding.

     See also the *note filesystem encoding and error handler: 53e.

magic method

     An informal synonym for *note special method: 1a06.

mapping

     A container object that supports arbitrary key lookups and
     implements the methods specified in the *note
     collections.abc.Mapping: 8d3. or *note
     collections.abc.MutableMapping: 10f0. *note abstract base classes:
     87f.  Examples include *note dict: 256, *note
     collections.defaultdict: 1201, *note collections.OrderedDict: 5de.
     and *note collections.Counter: 10d5.

meta path finder

     A *note finder: 20cd. returned by a search of *note sys.meta_path:
     d53.  Meta path finders are related to, but different from *note
     path entry finders: 10af.

     See *note importlib.abc.MetaPathFinder: 875. for the methods that
     meta path finders implement.

metaclass

     The class of a class.  Class definitions create a class name, a
     class dictionary, and a list of base classes.  The metaclass is
     responsible for taking those three arguments and creating the
     class.  Most object oriented programming languages provide a
     default implementation.  What makes Python special is that it is
     possible to create custom metaclasses.  Most users never need this
     tool, but when the need arises, metaclasses can provide powerful,
     elegant solutions.  They have been used for logging attribute
     access, adding thread-safety, tracking object creation,
     implementing singletons, and many other tasks.

     More information can be found in *note Metaclasses: 2124.

method

     A function which is defined inside a class body.  If called as an
     attribute of an instance of that class, the method will get the
     instance object as its first *note argument: 44c. (which is usually
     called ‘self’).  See *note function: 220d. and *note nested scope:
     20f3.

method resolution order

     Method Resolution Order is the order in which base classes are
     searched for a member during lookup.  See *note The Python 2.3
     Method Resolution Order: 14f9. for details of the algorithm used by
     the Python interpreter since the 2.3 release.

module

     An object that serves as an organizational unit of Python code.
     Modules have a namespace containing arbitrary Python objects.
     Modules are loaded into Python by the process of *note importing:
     219c.

     See also *note package: 20c9.

module spec

     A namespace containing the import-related information used to load
     a module.  An instance of *note importlib.machinery.ModuleSpec:
     200d.

     See also *note Module specs: 20c8.

MRO

     See *note method resolution order: 2339.

mutable

     An *note object: 5625. with state that is allowed to change during
     the course of the program.  In multi-threaded programs, mutable
     objects that are shared between threads require careful
     synchronization to avoid *note race conditions: 5609.  See also
     *note immutable: 1d91, *note thread-safe: 5616, and *note
     concurrent modification: 5610.

named tuple

     The term “named tuple” applies to any type or class that inherits
     from tuple and whose indexable elements are also accessible using
     named attributes.  The type or class may have other features as
     well.

     Several built-in types are named tuples, including the values
     returned by *note time.localtime(): 1548. and *note os.stat(): 4a3.
     Another example is *note sys.float_info: 1b7b.:

          >>> sys.float_info[1]                   # indexed access
          1024
          >>> sys.float_info.max_exp              # named field access
          1024
          >>> isinstance(sys.float_info, tuple)   # kind of tuple
          True

     Some named tuples are built-in types (such as the above examples).
     Alternatively, a named tuple can be created from a regular class
     definition that inherits from *note tuple: 373. and that defines
     named fields.  Such a class can be written by hand, or it can be
     created by inheriting *note typing.NamedTuple: 2b0, or with the
     factory function *note collections.namedtuple(): 1ca.  The latter
     techniques also add some extra methods that may not be found in
     hand-written or built-in named tuples.

namespace

     The place where a variable is stored.  Namespaces are implemented
     as dictionaries.  There are the local, global and built-in
     namespaces as well as nested namespaces in objects (in methods).
     Namespaces support modularity by preventing naming conflicts.  For
     instance, the functions *note builtins.open: 51f. and *note
     os.open(): dc0. are distinguished by their namespaces.  Namespaces
     also aid readability and maintainability by making it clear which
     module implements a function.  For instance, writing *note
     random.seed(): 12ba. or *note itertools.islice(): b67. makes it
     clear that those functions are implemented by the *note random: b8.
     and *note itertools: 81. modules, respectively.

namespace package

     A *note package: 20c9. which serves only as a container for
     subpackages.  Namespace packages may have no physical
     representation, and specifically are not like a *note regular
     package: 21a0. because they have no ‘__init__.py’ file.

     Namespace packages allow several individually installable packages
     to have a common parent package.  Otherwise, it is recommended to
     use a *note regular package: 21a0.

     For more information, see PEP 420(27) and *note Namespace packages:
     21a2.

     See also *note module: 1772.

native code

     Code that is compiled to machine instructions and runs directly on
     the processor, as opposed to code that is interpreted or runs in a
     virtual machine.  In the context of Python, native code typically
     refers to C, C++, Rust or Fortran code in *note extension modules:
     480c. that can be called from Python.  See also extension module.

nested scope

     The ability to refer to a variable in an enclosing definition.  For
     instance, a function defined inside another function can refer to
     variables in the outer function.  Note that nested scopes by
     default work only for reference and not for assignment.  Local
     variables both read and write in the innermost scope.  Likewise,
     global variables read and write to the global namespace.  The *note
     nonlocal: 12ef. allows writing to outer scopes.

new-style class

     Old name for the flavor of classes now used for all class objects.
     In earlier Python versions, only new-style classes could use
     Python’s newer, versatile features like *note __slots__: 153a,
     descriptors, properties, *note __getattribute__(): bf1, class
     methods, and static methods.

non-deterministic

     Behavior where the outcome of a program can vary between executions
     with the same inputs.  In multi-threaded programs,
     non-deterministic behavior often results from *note race
     conditions: 5609. where the relative timing or interleaving of
     threads affects the result.  Proper synchronization using *note
     locks: 5613. and other *note synchronization primitives: 5614.
     helps ensure deterministic behavior.

object

     Any data with state (attributes or value) and defined behavior
     (methods).  Also the ultimate base class of any *note new-style
     class: 2a5e.

optimized scope

     A scope where target local variable names are reliably known to the
     compiler when the code is compiled, allowing optimization of read
     and write access to these names.  The local namespaces for
     functions, generators, coroutines, comprehensions, and generator
     expressions are optimized in this fashion.  Note: most interpreter
     optimizations are applied to all scopes, only those relying on a
     known set of local and nonlocal variable names are restricted to
     optimized scopes.

package

     A Python *note module: 1772. which can contain submodules or
     recursively, subpackages.  Technically, a package is a Python
     module with a ‘__path__’ attribute.

     See also *note regular package: 21a0. and *note namespace package:
     1e06.

parallelism

     Executing multiple operations at the same time (e.g.  on multiple
     CPU cores).  In Python builds with the *note global interpreter
     lock (GIL): 148, only one thread runs Python bytecode at a time, so
     taking advantage of multiple CPU cores typically involves multiple
     processes (e.g.  *note multiprocessing: 94.) or native extensions
     that release the GIL. In *note free-threaded: 15b3. Python,
     multiple Python threads can run Python code simultaneously on
     different cores.

parameter

     A named entity in a *note function: 220d. (or method) definition
     that specifies an *note argument: 44c. (or in some cases,
     arguments) that the function can accept.  There are five kinds of
     parameter:

        * 'positional-or-keyword': specifies an argument that can be
          passed either *note positionally: 44c. or as a keyword
          argument.  This is the default kind of parameter, for example
          'foo' and 'bar' in the following:

               def func(foo, bar=None): ...

        * 'positional-only': specifies an argument that can be supplied
          only by position.  Positional-only parameters can be defined
          by including a ‘/’ character in the parameter list of the
          function definition after them, for example 'posonly1' and
          'posonly2' in the following:

               def func(posonly1, posonly2, /, positional_or_keyword): ...

        * 'keyword-only': specifies an argument that can be supplied
          only by keyword.  Keyword-only parameters can be defined by
          including a single var-positional parameter or bare ‘*’ in the
          parameter list of the function definition before them, for
          example 'kw_only1' and 'kw_only2' in the following:

               def func(arg, *, kw_only1, kw_only2): ...

        * 'var-positional': specifies that an arbitrary sequence of
          positional arguments can be provided (in addition to any
          positional arguments already accepted by other parameters).
          Such a parameter can be defined by prepending the parameter
          name with ‘*’, for example 'args' in the following:

               def func(*args, **kwargs): ...

        * 'var-keyword': specifies that arbitrarily many keyword
          arguments can be provided (in addition to any keyword
          arguments already accepted by other parameters).  Such a
          parameter can be defined by prepending the parameter name with
          ‘**’, for example 'kwargs' in the example above.

     Parameters can specify both optional and required arguments, as
     well as default values for some optional arguments.

     See also the *note argument: 44c. glossary entry, the FAQ question
     on *note the difference between arguments and parameters: 5541, the
     *note inspect.Parameter: 1d0. class, the *note Function
     definitions: 1dce. section, and PEP 362(28).

per-object lock

     A *note lock: 5613. associated with an individual object instance
     rather than a global lock shared across all objects.  In *note
     free-threaded: 15b3. Python, built-in types like *note dict: 256.
     and *note list: 614. use per-object locks to allow concurrent
     operations on different objects while serializing operations on the
     same object.  Operations that hold the per-object lock prevent
     other locking operations on the same object from proceeding, but do
     not block *note lock-free: 5623. operations.

path entry

     A single location on the *note import path: 21a9. which the *note
     path based finder: 21ac. consults to find modules for importing.

path entry finder

     A *note finder: 20cd. returned by a callable on *note
     sys.path_hooks: 105f. (i.e.  a *note path entry hook: 21b9.) which
     knows how to locate modules given a *note path entry: 21b7.

     See *note importlib.abc.PathEntryFinder: 876. for the methods that
     path entry finders implement.

path entry hook

     A callable on the *note sys.path_hooks: 105f. list which returns a
     *note path entry finder: 10af. if it knows how to find modules on a
     specific *note path entry: 21b7.

path based finder

     One of the default *note meta path finders: 10ae. which searches an
     *note import path: 21a9. for modules.

path-like object

     An object representing a file system path.  A path-like object is
     either a *note str: 44f. or *note bytes: 1c2. object representing a
     path, or an object implementing the *note os.PathLike: c72.
     protocol.  An object that supports the ‘os.PathLike’ protocol can
     be converted to a ‘str’ or ‘bytes’ file system path by calling the
     *note os.fspath(): c74. function; *note os.fsdecode(): c75. and
     *note os.fsencode(): c76. can be used to guarantee a ‘str’ or
     ‘bytes’ result instead, respectively.  Introduced by PEP 519(29).

PEP

     Python Enhancement Proposal.  A PEP is a design document providing
     information to the Python community, or describing a new feature
     for Python or its processes or environment.  PEPs should provide a
     concise technical specification and a rationale for proposed
     features.

     PEPs are intended to be the primary mechanisms for proposing major
     new features, for collecting community input on an issue, and for
     documenting the design decisions that have gone into Python.  The
     PEP author is responsible for building consensus within the
     community and documenting dissenting opinions.

     See PEP 1(30).

portion

     A set of files in a single directory (possibly stored in a zip
     file) that contribute to a namespace package, as defined in PEP
     420(31).

positional argument

     See *note argument: 44c.

provisional API

     A provisional API is one which has been deliberately excluded from
     the standard library’s backwards compatibility guarantees.  While
     major changes to such interfaces are not expected, as long as they
     are marked provisional, backwards incompatible changes (up to and
     including removal of the interface) may occur if deemed necessary
     by core developers.  Such changes will not be made gratuitously –
     they will occur only if serious fundamental flaws are uncovered
     that were missed prior to the inclusion of the API.

     Even for provisional APIs, backwards incompatible changes are seen
     as a “solution of last resort” - every attempt will still be made
     to find a backwards compatible resolution to any identified
     problems.

     This process allows the standard library to continue to evolve over
     time, without locking in problematic design errors for extended
     periods of time.  See PEP 411(32) for more details.

provisional package

     See *note provisional API: b1c.

Python 3000

     Nickname for the Python 3.x release line (coined long ago when the
     release of version 3 was something in the distant future.)  This is
     also abbreviated “Py3k”.

Pythonic

     An idea or piece of code which closely follows the most common
     idioms of the Python language, rather than implementing code using
     concepts common to other languages.  For example, a common idiom in
     Python is to loop over all elements of an iterable using a *note
     for: 2f2. statement.  Many other languages don’t have this type of
     construct, so people unfamiliar with Python sometimes use a
     numerical counter instead:

          for i in range(len(food)):
              print(food[i])

     As opposed to the cleaner, Pythonic method:

          for piece in food:
              print(piece)

qualified name

     A dotted name showing the “path” from a module’s global scope to a
     class, function or method defined in that module, as defined in PEP
     3155(33).  For top-level functions and classes, the qualified name
     is the same as the object’s name:

          >>> class C:
          ...     class D:
          ...         def meth(self):
          ...             pass
          ...
          >>> C.__qualname__
          'C'
          >>> C.D.__qualname__
          'C.D'
          >>> C.D.meth.__qualname__
          'C.D.meth'

     When used to refer to modules, the 'fully qualified name' means the
     entire dotted path to the module, including any parent packages,
     e.g.  ‘email.mime.text’:

          >>> import email.mime.text
          >>> email.mime.text.__name__
          'email.mime.text'

race condition

     A condition of a program where the behavior depends on the relative
     timing or ordering of events, particularly in multi-threaded
     programs.  Race conditions can lead to *note non-deterministic:
     5612. behavior and bugs that are difficult to reproduce.  A *note
     data race: 560a. is a specific type of race condition involving
     unsynchronized access to shared memory.  The *note LBYL: 561b.
     coding style is particularly susceptible to race conditions in
     multi-threaded code.  Using *note locks: 5613. and other *note
     synchronization primitives: 5614. helps prevent race conditions.

reference count

     The number of references to an object.  When the reference count of
     an object drops to zero, it is deallocated.  Some objects are *note
     immortal: 45dd. and have reference counts that are never modified,
     and therefore the objects are never deallocated.  Reference
     counting is generally not visible to Python code, but it is a key
     element of the *note CPython: 6f9. implementation.  Programmers can
     call the *note sys.getrefcount(): 45dc. function to return the
     reference count for a particular object.

     In *note CPython: 6f9, reference counts are not considered to be
     stable or well-defined values; the number of references to an
     object, and how that number is affected by Python code, may be
     different between versions.

regular package

     A traditional *note package: 20c9, such as a directory containing
     an ‘__init__.py’ file.

     See also *note namespace package: 1e06.

reentrant

     A property of a function or *note lock: 5613. that allows it to be
     called or acquired multiple times by the same thread without
     causing errors or a *note deadlock: 5617.

     For functions, reentrancy means the function can be safely called
     again before a previous invocation has completed, which is
     important when functions may be called recursively or from signal
     handlers.  Thread-unsafe functions may be *note non-deterministic:
     5612. if they’re called reentrantly in a multithreaded program.

     For locks, Python’s *note threading.RLock: 2de. (reentrant lock) is
     reentrant, meaning a thread that already holds the lock can acquire
     it again without blocking.  In contrast, *note threading.Lock:
     178a. is not reentrant - attempting to acquire it twice from the
     same thread will cause a deadlock.

     See also *note lock: 5613. and *note deadlock: 5617.

REPL

     An acronym for the “read–eval–print loop”, another name for the
     *note interactive: 169. interpreter shell.

__slots__

     A declaration inside a class that saves memory by pre-declaring
     space for instance attributes and eliminating instance
     dictionaries.  Though popular, the technique is somewhat tricky to
     get right and is best reserved for rare cases where there are large
     numbers of instances in a memory-critical application.

sequence

     An *note iterable: 126d. which supports efficient element access
     using integer indices via the *note __getitem__(): 283. special
     method and defines a *note __len__(): 15da. method that returns the
     length of the sequence.  Some built-in sequence types are *note
     list: 614, *note str: 44f, *note tuple: 373, and *note bytes: 1c2.
     Note that *note dict: 256. also supports ‘__getitem__()’ and
     ‘__len__()’, but is considered a mapping rather than a sequence
     because the lookups use arbitrary *note hashable: 613. keys rather
     than integers.

     The *note collections.abc.Sequence: 1209. abstract base class
     defines a much richer interface that goes beyond just *note
     __getitem__(): 283. and *note __len__(): 15da, adding *note
     count(): 213e, *note index(): 2140, *note __contains__(): 1406, and
     *note __reversed__(): cad.  Types that implement this expanded
     interface can be registered explicitly using *note register():
     10cc.  For more documentation on sequence methods generally, see
     *note Common Sequence Operations: 2361.

set comprehension

     A compact way to process all or part of the elements in an iterable
     and return a set with the results.  ‘results = {c for c in
     'abracadabra' if c not in 'abc'}’ generates the set of strings
     ‘{'r', 'd'}’.  See *note Displays for lists, sets and dictionaries:
     5d3.

single dispatch

     A form of *note generic function: 9fc. dispatch where the
     implementation is chosen based on the type of a single argument.

slice

     An object usually containing a portion of a *note sequence: 4f4.  A
     slice is created using the subscript notation, ‘[]’ with colons
     between numbers when several are given, such as in
     ‘variable_name[1:3:5]’.  The bracket (subscript) notation uses
     *note slice: 46c. objects internally.

soft deprecated

     A soft deprecated API should not be used in new code, but it is
     safe for already existing code to use it.  The API remains
     documented and tested, but will not be enhanced further.

     Soft deprecation, unlike normal deprecation, does not plan on
     removing the API and will not emit warnings.

     See PEP 387: Soft Deprecation(34).

special method

     A method that is called implicitly by Python to execute a certain
     operation on a type, such as addition.  Such methods have names
     starting and ending with double underscores.  Special methods are
     documented in *note Special method names: c8f.

standard library

     The collection of *note packages: 20c9, *note modules: 1772. and
     *note extension modules: 480c. distributed as a part of the
     official Python interpreter package.  The exact membership of the
     collection may vary based on platform, available system libraries,
     or other criteria.  Documentation can be found at *note The Python
     Standard Library: 144.

     See also *note sys.stdlib_module_names: 847. for a list of all
     possible standard library module names.

statement

     A statement is part of a suite (a “block” of code).  A statement is
     either an *note expression: 2135. or one of several constructs with
     a keyword, such as *note if: 2f3, *note while: 1d9a. or *note for:
     2f2.

static type checker

     An external tool that reads Python code and analyzes it, looking
     for issues such as incorrect types.  See also *note type hints:
     2131. and the *note typing: 104. module.

stdlib

     An abbreviation of *note standard library: 562a.

strong reference

     In Python’s C API, a strong reference is a reference to an object
     which is owned by the code holding the reference.  The strong
     reference is taken by calling *note Py_INCREF(): 571. when the
     reference is created and released with *note Py_DECREF(): 572. when
     the reference is deleted.

     The *note Py_NewRef(): 8a1. function can be used to create a strong
     reference to an object.  Usually, the *note Py_DECREF(): 572.
     function must be called on the strong reference before exiting the
     scope of the strong reference, to avoid leaking one reference.

     See also *note borrowed reference: 33f.

synchronization primitive

     A basic building block for coordinating (synchronizing) the
     execution of multiple threads to ensure *note thread-safe: 5616.
     access to shared resources.  Python’s *note threading: ed. module
     provides several synchronization primitives including *note Lock:
     178a, *note RLock: 2de, *note Semaphore: 119a, *note Condition:
     1199, *note Event: 119c, and *note Barrier: 1228.  Additionally,
     the *note queue: b6. module provides multi-producer, multi-consumer
     queues that are especially useful in multithreaded programs.  These
     primitives help prevent *note race conditions: 5609. and coordinate
     thread execution.  See also *note lock: 5613.

text encoding

     A string in Python is a sequence of Unicode code points (in range
     ‘U+0000’–‘U+10FFFF’).  To store or transfer a string, it needs to
     be serialized as a sequence of bytes.

     Serializing a string into a sequence of bytes is known as
     “encoding”, and recreating the string from the sequence of bytes is
     known as “decoding”.

     There are a variety of different text serialization *note codecs:
     de7, which are collectively referred to as “text encodings”.

text file

     A *note file object: 1208. able to read and write *note str: 44f.
     objects.  Often, a text file actually accesses a byte-oriented
     datastream and handles the *note text encoding: 2333.
     automatically.  Examples of text files are files opened in text
     mode (‘'r'’ or ‘'w'’), *note sys.stdin: 540, *note sys.stdout: aec,
     and instances of *note io.StringIO: f5e.

     See also *note binary file: 1e26. for a file object able to read
     and write *note bytes-like objects: d55.

thread-safe

     A module, function, or class that behaves correctly when used by
     multiple threads concurrently.  Thread-safe code uses appropriate
     *note synchronization primitives: 5614. like *note locks: 5613. to
     protect shared mutable state, or is designed to avoid shared
     mutable state entirely.  In the *note free-threaded: 15b3. build,
     built-in types like *note dict: 256, *note list: 614, and *note
     set: 5dc. use internal locking to make many operations thread-safe,
     although thread safety is not necessarily guaranteed.  Code that is
     not thread-safe may experience *note race conditions: 5609. and
     *note data races: 560a. when used in multi-threaded programs.

token

     A small unit of source code, generated by the *note lexical
     analyzer: 2026. (also called the 'tokenizer').  Names, numbers,
     strings, operators, newlines and similar are represented by tokens.

     The *note tokenize: fb. module exposes Python’s lexical analyzer.
     The *note token: fa. module contains information on the various
     types of tokens.

triple-quoted string

     A string which is bound by three instances of either a quotation
     mark (”) or an apostrophe (‘).  While they don’t provide any
     functionality not available with single-quoted strings, they are
     useful for a number of reasons.  They allow you to include
     unescaped single and double quotes within a string and they can
     span multiple lines without the use of the continuation character,
     making them especially useful when writing docstrings.

type

     The type of a Python object determines what kind of object it is;
     every object has a type.  An object’s type is accessible as its
     *note __class__: 14fc. attribute or can be retrieved with
     ‘type(obj)’.

type alias

     A synonym for a type, created by assigning the type to an
     identifier.

     Type aliases are useful for simplifying *note type hints: 2131.
     For example:

          def remove_gray_shades(
                  colors: list[tuple[int, int, int]]) -> list[tuple[int, int, int]]:
              pass

     could be made more readable like this:

          Color = tuple[int, int, int]

          def remove_gray_shades(colors: list[Color]) -> list[Color]:
              pass

     See *note typing: 104. and PEP 484(35), which describe this
     functionality.

type hint

     An *note annotation: 45b. that specifies the expected type for a
     variable, a class attribute, or a function parameter or return
     value.

     Type hints are optional and are not enforced by Python but they are
     useful to *note static type checkers: 26d.  They can also aid IDEs
     with code completion and refactoring.

     Type hints of global variables, class attributes, and functions,
     but not local variables, can be accessed using *note
     typing.get_type_hints(): 6b4.

     See *note typing: 104. and PEP 484(36), which describe this
     functionality.

universal newlines

     A manner of interpreting text streams in which all of the following
     are recognized as ending a line: the Unix end-of-line convention
     ‘'\n'’, the Windows convention ‘'\r\n'’, and the old Macintosh
     convention ‘'\r'’.  See PEP 278(37) and PEP 3116(38), as well as
     *note bytes.splitlines(): 23ca. for an additional use.

variable annotation

     An *note annotation: 45b. of a variable or a class attribute.

     When annotating a variable or a class attribute, assignment is
     optional:

          class C:
              field: 'annotation'

     Variable annotations are usually used for *note type hints: 2131.:
     for example this variable is expected to take *note int: 257.
     values:

          count: int = 0

     Variable annotation syntax is explained in section *note Annotated
     assignment statements: 2264.

     See *note function annotation: 1dcf, PEP 484(39) and PEP 526(40),
     which describe this functionality.  Also see *note Annotations Best
     Practices: 7dd. for best practices on working with annotations.

virtual environment

     A cooperatively isolated runtime environment that allows Python
     users and applications to install and upgrade Python distribution
     packages without interfering with the behaviour of other Python
     applications running on the same system.

     See also *note venv: 111.

virtual machine

     A computer defined entirely in software.  Python’s virtual machine
     executes the *note bytecode: 187. emitted by the bytecode compiler.

walrus operator

     A light-hearted way to refer to the *note assignment expression:
     2235. operator ‘:=’ because it looks a bit like a walrus if you
     turn your head.

Zen of Python

     Listing of Python design principles and philosophies that are
     helpful in understanding and using the language.  The listing can
     be found by typing “‘import this’” at the interactive prompt.

   ---------- Footnotes ----------

   (1) https://peps.python.org/pep-0484/

   (2) https://peps.python.org/pep-0526/

   (3) https://peps.python.org/pep-0362/

   (4) https://peps.python.org/pep-0492/

   (5) https://peps.python.org/pep-0492/

   (6) https://peps.python.org/pep-0525/

   (7) https://peps.python.org/pep-0492/

   (8) https://peps.python.org/pep-0492/

   (9) https://peps.python.org/pep-0492/

   (10) https://gvanrossum.github.io/

   (11) https://peps.python.org/pep-0343/

   (12) https://peps.python.org/pep-0343/

   (13) https://peps.python.org/pep-0492/

   (14) https://peps.python.org/pep-0492/

   (15) https://www.python.org

   (16) https://peps.python.org/pep-0498/

   (17) https://peps.python.org/pep-0238/

   (18) https://peps.python.org/pep-0703/

   (19) https://peps.python.org/pep-0484/

   (20) https://peps.python.org/pep-0443/

   (21) https://peps.python.org/pep-0483/

   (22) https://peps.python.org/pep-0484/

   (23) https://peps.python.org/pep-0585/

   (24) https://peps.python.org/pep-0703/

   (25) https://peps.python.org/pep-0683/

   (26) https://peps.python.org/pep-0302/

   (27) https://peps.python.org/pep-0420/

   (28) https://peps.python.org/pep-0362/

   (29) https://peps.python.org/pep-0519/

   (30) https://peps.python.org/pep-0001/

   (31) https://peps.python.org/pep-0420/

   (32) https://peps.python.org/pep-0411/

   (33) https://peps.python.org/pep-3155/

   (34) https://peps.python.org/pep-0387/#soft-deprecation

   (35) https://peps.python.org/pep-0484/

   (36) https://peps.python.org/pep-0484/

   (37) https://peps.python.org/pep-0278/

   (38) https://peps.python.org/pep-3116/

   (39) https://peps.python.org/pep-0484/

   (40) https://peps.python.org/pep-0526/


File: python.info,  Node: About this documentation,  Next: Dealing with Bugs,  Prev: Glossary,  Up: Top

13 About this documentation
***************************

Python’s documentation is generated from reStructuredText(1) sources
using Sphinx(2), a documentation generator originally created for Python
and now maintained as an independent project.

Development of the documentation and its toolchain is an entirely
volunteer effort, just like Python itself.  If you want to contribute,
please take a look at the *note Dealing with Bugs: 4be4. page for
information on how to do so.  New volunteers are always welcome!

Many thanks go to:

   * Fred L. Drake, Jr., the creator of the original Python
     documentation toolset and author of much of the content;

   * the Docutils(3) project for creating reStructuredText and the
     Docutils suite;

   * Fredrik Lundh for his Alternative Python Reference project from
     which Sphinx got many good ideas.

* Menu:

* Contributors to the Python documentation::

   ---------- Footnotes ----------

   (1) https://docutils.sourceforge.io/rst.html

   (2) https://www.sphinx-doc.org/

   (3) https://docutils.sourceforge.io/


File: python.info,  Node: Contributors to the Python documentation,  Up: About this documentation

13.1 Contributors to the Python documentation
=============================================

Many people have contributed to the Python language, the Python standard
library, and the Python documentation.  See Misc/ACKS(1) in the Python
source distribution for a partial list of contributors.

It is only with the input and contributions of the Python community that
Python has such wonderful documentation – Thank You!

   ---------- Footnotes ----------

   (1) https://github.com/python/cpython/tree/3.13/Misc/ACKS


File: python.info,  Node: Dealing with Bugs,  Next: Copyright,  Prev: About this documentation,  Up: Top

14 Dealing with Bugs
********************

Python is a mature programming language which has established a
reputation for stability.  In order to maintain this reputation, the
developers would like to know of any deficiencies you find in Python.

It can be sometimes faster to fix bugs yourself and contribute patches
to Python as it streamlines the process and involves fewer people.
Learn how to *note contribute: 5635.

* Menu:

* Documentation bugs::
* Using the Python issue tracker::
* Getting started contributing to Python yourself::


File: python.info,  Node: Documentation bugs,  Next: Using the Python issue tracker,  Up: Dealing with Bugs

14.1 Documentation bugs
=======================

If you find a bug in this documentation or would like to propose an
improvement, please submit a bug report on the *note issue tracker: 24e.
If you have a suggestion on how to fix it, include that as well.

You can also open a discussion item on our Documentation Discourse
forum(1).

If you find a bug in the theme (HTML / CSS / JavaScript) of the
documentation, please submit a bug report on the python-doc-theme issue
tracker(2).

See also
........

Documentation bugs(3)

     A list of documentation bugs that have been submitted to the Python
     issue tracker.

Issue Tracking(4)

     Overview of the process involved in reporting an improvement on the
     tracker.

Helping with Documentation(5)

     Comprehensive guide for individuals that are interested in
     contributing to Python documentation.

Documentation Translations(6)

     A list of GitHub pages for documentation translation and their
     primary contacts.

   ---------- Footnotes ----------

   (1) https://discuss.python.org/c/documentation/26

   (2) https://github.com/python/python-docs-theme

   (3) 
https://github.com/python/cpython/issues?q=is%3Aissue+is%3Aopen+label%3Adocs

   (4) https://devguide.python.org/tracker/

   (5) 
https://devguide.python.org/docquality/#helping-with-documentation

   (6) https://devguide.python.org/documentation/translating/


File: python.info,  Node: Using the Python issue tracker,  Next: Getting started contributing to Python yourself,  Prev: Documentation bugs,  Up: Dealing with Bugs

14.2 Using the Python issue tracker
===================================

Issue reports for Python itself should be submitted via the GitHub
issues tracker (‘https://github.com/python/cpython/issues’).  The GitHub
issues tracker offers a web form which allows pertinent information to
be entered and submitted to the developers.

The first step in filing a report is to determine whether the problem
has already been reported.  The advantage in doing so, aside from saving
the developers’ time, is that you learn what has been done to fix it; it
may be that the problem has already been fixed for the next release, or
additional information is needed (in which case you are welcome to
provide it if you can!).  To do this, search the tracker using the
search box at the top of the page.

If the problem you’re reporting is not already in the list, log in to
GitHub.  If you don’t already have a GitHub account, create a new
account using the “Sign up” link.  It is not possible to submit a bug
report anonymously.

Being now logged in, you can submit an issue.  Click on the “New issue”
button in the top bar to report a new issue.

The submission form has two fields, “Title” and “Comment”.

For the “Title” field, enter a 'very' short description of the problem;
fewer than ten words is good.

In the “Comment” field, describe the problem in detail, including what
you expected to happen and what did happen.  Be sure to include whether
any extension modules were involved, and what hardware and software
platform you were using (including version information as appropriate).

Each issue report will be reviewed by a developer who will determine
what needs to be done to correct the problem.  You will receive an
update each time an action is taken on the issue.

See also
........

How to Report Bugs Effectively(1)

     Article which goes into some detail about how to create a useful
     bug report.  This describes what kind of information is useful and
     why it is useful.

Bug Writing Guidelines(2)

     Information about writing a good bug report.  Some of this is
     specific to the Mozilla project, but describes general good
     practices.

   ---------- Footnotes ----------

   (1) https://www.chiark.greenend.org.uk/~sgtatham/bugs.html

   (2) https://bugzilla.mozilla.org/page.cgi?id=bug-writing.html


File: python.info,  Node: Getting started contributing to Python yourself,  Prev: Using the Python issue tracker,  Up: Dealing with Bugs

14.3 Getting started contributing to Python yourself
====================================================

Beyond just reporting bugs that you find, you are also welcome to submit
patches to fix them.  You can find more information on how to get
started patching Python in the Python Developer's Guide(1).  If you have
questions, the core-mentorship mailing list(2) is a friendly place to
get answers to any and all questions pertaining to the process of fixing
issues in Python.

   ---------- Footnotes ----------

   (1) https://devguide.python.org/

   (2) 
https://mail.python.org/mailman3/lists/core-mentorship.python.org/


File: python.info,  Node: Copyright,  Next: History and License,  Prev: Dealing with Bugs,  Up: Top

15 Copyright
************

Python and this documentation is:

Copyright © 2001-2024 Python Software Foundation.  All rights reserved.

Copyright © 2000 BeOpen.com.  All rights reserved.

Copyright © 1995-2000 Corporation for National Research Initiatives.
All rights reserved.

Copyright © 1991-1995 Stichting Mathematisch Centrum.  All rights
reserved.

__________________________________________________________________

See *note History and License: 563c. for complete license and
permissions information.


File: python.info,  Node: History and License,  Next: Python Module Index,  Prev: Copyright,  Up: Top

16 History and License
**********************

* Menu:

* History of the software::
* Terms and conditions for accessing or otherwise using Python::
* Licenses and Acknowledgements for Incorporated Software::


File: python.info,  Node: History of the software,  Next: Terms and conditions for accessing or otherwise using Python,  Up: History and License

16.1 History of the software
============================

Python was created in the early 1990s by Guido van Rossum at Stichting
Mathematisch Centrum (CWI, see ‘https://www.cwi.nl’) in the Netherlands
as a successor of a language called ABC. Guido remains Python’s
principal author, although it includes many contributions from others.

In 1995, Guido continued his work on Python at the Corporation for
National Research Initiatives (CNRI, see
‘https://www.cnri.reston.va.us’) in Reston, Virginia where he released
several versions of the software.

In May 2000, Guido and the Python core development team moved to
BeOpen.com to form the BeOpen PythonLabs team.  In October of the same
year, the PythonLabs team moved to Digital Creations, which became Zope
Corporation.  In 2001, the Python Software Foundation (PSF, see
‘https://www.python.org/psf/’) was formed, a non-profit organization
created specifically to own Python-related Intellectual Property.  Zope
Corporation was a sponsoring member of the PSF.

All Python releases are Open Source (see ‘https://opensource.org’ for
the Open Source Definition).  Historically, most, but not all, Python
releases have also been GPL-compatible; the table below summarizes the
various releases.

Release              Derived from       Year             Owner            GPL-compatible?  (1)
                                                                          
----------------------------------------------------------------------------------------------------
                                                                          
0.9.0 thru 1.2       n/a                1991-1995        CWI              yes
                                                                          
                                                                          
1.3 thru 1.5.2       1.2                1995-1999        CNRI             yes
                                                                          
                                                                          
1.6                  1.5.2              2000             CNRI             no
                                                                          
                                                                          
2.0                  1.6                2000             BeOpen.com       no
                                                                          
                                                                          
1.6.1                1.6                2001             CNRI             yes (2)
                                                                          
                                                                          
2.1                  2.0+1.6.1          2001             PSF              no
                                                                          
                                                                          
2.0.1                2.0+1.6.1          2001             PSF              yes
                                                                          
                                                                          
2.1.1                2.1+2.0.1          2001             PSF              yes
                                                                          
                                                                          
2.1.2                2.1.1              2002             PSF              yes
                                                                          
                                                                          
2.1.3                2.1.2              2002             PSF              yes
                                                                          
                                                                          
2.2 and above        2.1.1              2001-now         PSF              yes
                                                                          

     Note: 
       1. GPL-compatible doesn’t mean that we’re distributing Python
          under the GPL. All Python licenses, unlike the GPL, let you
          distribute a modified version without making your changes open
          source.  The GPL-compatible licenses make it possible to
          combine Python with other software that is released under the
          GPL; the others don’t.

       2. According to Richard Stallman, 1.6.1 is not GPL-compatible,
          because its license has a choice of law clause.  According to
          CNRI, however, Stallman’s lawyer has told CNRI’s lawyer that
          1.6.1 is “not incompatible” with the GPL.

Thanks to the many outside volunteers who have worked under Guido’s
direction to make these releases possible.


File: python.info,  Node: Terms and conditions for accessing or otherwise using Python,  Next: Licenses and Acknowledgements for Incorporated Software,  Prev: History of the software,  Up: History and License

16.2 Terms and conditions for accessing or otherwise using Python
=================================================================

Python software and documentation are licensed under the Python Software
Foundation License Version 2.

Starting with Python 3.8.6, examples, recipes, and other code in the
documentation are dual licensed under the PSF License Version 2 and the
*note Zero-Clause BSD license: 5642.

Some software incorporated into Python is under different licenses.  The
licenses are listed with code falling under that license.  See *note
Licenses and Acknowledgements for Incorporated Software: 5643. for an
incomplete list of these licenses.

* Menu:

* PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2::
* BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 0.
* CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 1.
* CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 2.
* ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION::


File: python.info,  Node: PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2,  Next: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 0,  Up: Terms and conditions for accessing or otherwise using Python

16.2.1 PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
---------------------------------------------------

     1. This LICENSE AGREEMENT is between the Python Software Foundation ("PSF"), and
        the Individual or Organization ("Licensee") accessing and otherwise using this
        software ("Python") in source or binary form and its associated documentation.

     2. Subject to the terms and conditions of this License Agreement, PSF hereby
        grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
        analyze, test, perform and/or display publicly, prepare derivative works,
        distribute, and otherwise use Python alone or in any derivative
        version, provided, however, that PSF's License Agreement and PSF's notice of
        copyright, i.e., "Copyright © 2001-2024 Python Software Foundation; All Rights
        Reserved" are retained in Python alone or in any derivative version
        prepared by Licensee.

     3. In the event Licensee prepares a derivative work that is based on or
        incorporates Python or any part thereof, and wants to make the
        derivative work available to others as provided herein, then Licensee hereby
        agrees to include in any such work a brief summary of the changes made to Python.

     4. PSF is making Python available to Licensee on an "AS IS" basis.
        PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF
        EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY REPRESENTATION OR
        WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE
        USE OF PYTHON WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

     5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
        FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
        MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON, OR ANY DERIVATIVE
        THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

     6. This License Agreement will automatically terminate upon a material breach of
        its terms and conditions.

     7. Nothing in this License Agreement shall be deemed to create any relationship
        of agency, partnership, or joint venture between PSF and Licensee.  This License
        Agreement does not grant permission to use PSF trademarks or trade name in a
        trademark sense to endorse or promote products or services of Licensee, or any
        third party.

     8. By copying, installing or otherwise using Python, Licensee agrees
        to be bound by the terms and conditions of this License Agreement.


File: python.info,  Node: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 0,  Next: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 1,  Prev: PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2,  Up: Terms and conditions for accessing or otherwise using Python

16.2.2 BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0
--------------------------------------------------

BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1

     1. This LICENSE AGREEMENT is between BeOpen.com ("BeOpen"), having an office at
        160 Saratoga Avenue, Santa Clara, CA 95051, and the Individual or Organization
        ("Licensee") accessing and otherwise using this software in source or binary
        form and its associated documentation ("the Software").

     2. Subject to the terms and conditions of this BeOpen Python License Agreement,
        BeOpen hereby grants Licensee a non-exclusive, royalty-free, world-wide license
        to reproduce, analyze, test, perform and/or display publicly, prepare derivative
        works, distribute, and otherwise use the Software alone or in any derivative
        version, provided, however, that the BeOpen Python License is retained in the
        Software, alone or in any derivative version prepared by Licensee.

     3. BeOpen is making the Software available to Licensee on an "AS IS" basis.
        BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF
        EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND DISCLAIMS ANY REPRESENTATION OR
        WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE
        USE OF THE SOFTWARE WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

     4. BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE SOFTWARE FOR
        ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF USING,
        MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY DERIVATIVE THEREOF, EVEN IF
        ADVISED OF THE POSSIBILITY THEREOF.

     5. This License Agreement will automatically terminate upon a material breach of
        its terms and conditions.

     6. This License Agreement shall be governed by and interpreted in all respects
        by the law of the State of California, excluding conflict of law provisions.
        Nothing in this License Agreement shall be deemed to create any relationship of
        agency, partnership, or joint venture between BeOpen and Licensee.  This License
        Agreement does not grant permission to use BeOpen trademarks or trade names in a
        trademark sense to endorse or promote products or services of Licensee, or any
        third party.  As an exception, the "BeOpen Python" logos available at
        ‘http://www.pythonlabs.com/logos.html’ may be used according to the permissions
        granted on that web page.

     7. By copying, installing or otherwise using the software, Licensee agrees to be
        bound by the terms and conditions of this License Agreement.


File: python.info,  Node: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 1,  Next: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 2,  Prev: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 0,  Up: Terms and conditions for accessing or otherwise using Python

16.2.3 CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1
----------------------------------------------

     1. This LICENSE AGREEMENT is between the Corporation for National Research
        Initiatives, having an office at 1895 Preston White Drive, Reston, VA 20191
        ("CNRI"), and the Individual or Organization ("Licensee") accessing and
        otherwise using Python 1.6.1 software in source or binary form and its
        associated documentation.

     2. Subject to the terms and conditions of this License Agreement, CNRI hereby
        grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
        analyze, test, perform and/or display publicly, prepare derivative works,
        distribute, and otherwise use Python 1.6.1 alone or in any derivative version,
        provided, however, that CNRI's License Agreement and CNRI's notice of copyright,
        i.e., "Copyright © 1995-2001 Corporation for National Research Initiatives; All
        Rights Reserved" are retained in Python 1.6.1 alone or in any derivative version
        prepared by Licensee.  Alternately, in lieu of CNRI's License Agreement,
        Licensee may substitute the following text (omitting the quotes): "Python 1.6.1
        is made available subject to the terms and conditions in CNRI's License
        Agreement.  This Agreement together with Python 1.6.1 may be located on the
        internet using the following unique, persistent identifier (known as a handle):
        1895.22/1013.  This Agreement may also be obtained from a proxy server on the
        internet using the following URL: ‘http://hdl.handle.net/1895.22/1013’".

     3. In the event Licensee prepares a derivative work that is based on or
        incorporates Python 1.6.1 or any part thereof, and wants to make the derivative
        work available to others as provided herein, then Licensee hereby agrees to
        include in any such work a brief summary of the changes made to Python 1.6.1.

     4. CNRI is making Python 1.6.1 available to Licensee on an "AS IS" basis.  CNRI
        MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.  BY WAY OF EXAMPLE,
        BUT NOT LIMITATION, CNRI MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY
        OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF
        PYTHON 1.6.1 WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.

     5. CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON 1.6.1 FOR
        ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
        MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1, OR ANY DERIVATIVE
        THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.

     6. This License Agreement will automatically terminate upon a material breach of
        its terms and conditions.

     7. This License Agreement shall be governed by the federal intellectual property
        law of the United States, including without limitation the federal copyright
        law, and, to the extent such U.S. federal law does not apply, by the law of the
        Commonwealth of Virginia, excluding Virginia's conflict of law provisions.
        Notwithstanding the foregoing, with regard to derivative works based on Python
        1.6.1 that incorporate non-separable material that was previously distributed
        under the GNU General Public License (GPL), the law of the Commonwealth of
        Virginia shall govern this License Agreement only as to issues arising under or
        with respect to Paragraphs 4, 5, and 7 of this License Agreement.  Nothing in
        this License Agreement shall be deemed to create any relationship of agency,
        partnership, or joint venture between CNRI and Licensee.  This License Agreement
        does not grant permission to use CNRI trademarks or trade name in a trademark
        sense to endorse or promote products or services of Licensee, or any third
        party.

     8. By clicking on the "ACCEPT" button where indicated, or by copying, installing
        or otherwise using Python 1.6.1, Licensee agrees to be bound by the terms and
        conditions of this License Agreement.


File: python.info,  Node: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 2,  Next: ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION,  Prev: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 1,  Up: Terms and conditions for accessing or otherwise using Python

16.2.4 CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2
---------------------------------------------------------

     Copyright © 1991 - 1995, Stichting Mathematisch Centrum Amsterdam, The
     Netherlands.  All rights reserved.

     Permission to use, copy, modify, and distribute this software and its
     documentation for any purpose and without fee is hereby granted, provided that
     the above copyright notice appear in all copies and that both that copyright
     notice and this permission notice appear in supporting documentation, and that
     the name of Stichting Mathematisch Centrum or CWI not be used in advertising or
     publicity pertaining to distribution of the software without specific, written
     prior permission.

     STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
     SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
     EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE FOR ANY SPECIAL, INDIRECT
     OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
     DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
     ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
     SOFTWARE.


File: python.info,  Node: ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION,  Prev: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 2,  Up: Terms and conditions for accessing or otherwise using Python

16.2.5 ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION
-------------------------------------------------------------------

     Permission to use, copy, modify, and/or distribute this software for any
     purpose with or without fee is hereby granted.

     THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
     REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
     INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
     LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
     OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
     PERFORMANCE OF THIS SOFTWARE.


File: python.info,  Node: Licenses and Acknowledgements for Incorporated Software,  Prev: Terms and conditions for accessing or otherwise using Python,  Up: History and License

16.3 Licenses and Acknowledgements for Incorporated Software
============================================================

This section is an incomplete, but growing list of licenses and
acknowledgements for third-party software incorporated in the Python
distribution.

* Menu:

* Mersenne Twister::
* Sockets: Sockets<2>.
* Asynchronous socket services::
* Cookie management::
* Execution tracing::
* UUencode and UUdecode functions::
* XML Remote Procedure Calls::
* test_epoll::
* Select kqueue::
* SipHash24::
* strtod and dtoa::
* OpenSSL: OpenSSL<2>.
* expat::
* libffi::
* zlib: zlib<3>.
* cfuhash::
* libmpdec::
* W3C C14N test suite::
* mimalloc::
* asyncio: asyncio<12>.
* Global Unbounded Sequences (GUS): Global Unbounded Sequences GUS.


File: python.info,  Node: Mersenne Twister,  Next: Sockets<2>,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.1 Mersenne Twister
-----------------------

The ‘_random’ C extension underlying the *note random: b8. module
includes code based on a download from
‘http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html’.
The following are the verbatim comments from the original code:

     A C-program for MT19937, with initialization improved 2002/1/26.
     Coded by Takuji Nishimura and Makoto Matsumoto.

     Before using, initialize the state by using init_genrand(seed)
     or init_by_array(init_key, key_length).

     Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:

      1. Redistributions of source code must retain the above copyright
         notice, this list of conditions and the following disclaimer.

      2. Redistributions in binary form must reproduce the above copyright
         notice, this list of conditions and the following disclaimer in the
         documentation and/or other materials provided with the distribution.

      3. The names of its contributors may not be used to endorse or promote
         products derived from this software without specific prior written
         permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


     Any feedback is very welcome.
     http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
     email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)


File: python.info,  Node: Sockets<2>,  Next: Asynchronous socket services,  Prev: Mersenne Twister,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.2 Sockets
--------------

The *note socket: cc. module uses the functions, ‘getaddrinfo()’, and
‘getnameinfo()’, which are coded in separate source files from the WIDE
Project, ‘https://www.wide.ad.jp/’.

     Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
     3. Neither the name of the project nor the names of its contributors
        may be used to endorse or promote products derived from this software
        without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS "AS IS" AND
     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.


File: python.info,  Node: Asynchronous socket services,  Next: Cookie management,  Prev: Sockets<2>,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.3 Asynchronous socket services
-----------------------------------

The ‘test.support.asynchat’ and ‘test.support.asyncore’ modules contain
the following notice:

     Copyright 1996 by Sam Rushing

                             All Rights Reserved

     Permission to use, copy, modify, and distribute this software and
     its documentation for any purpose and without fee is hereby
     granted, provided that the above copyright notice appear in all
     copies and that both that copyright notice and this permission
     notice appear in supporting documentation, and that the name of Sam
     Rushing not be used in advertising or publicity pertaining to
     distribution of the software without specific, written prior
     permission.

     SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
     INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
     NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
     CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
     OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
     NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
     CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.


File: python.info,  Node: Cookie management,  Next: Execution tracing,  Prev: Asynchronous socket services,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.4 Cookie management
------------------------

The *note http.cookies: 71. module contains the following notice:

     Copyright 2000 by Timothy O'Malley <timo@alum.mit.edu>

                    All Rights Reserved

     Permission to use, copy, modify, and distribute this software
     and its documentation for any purpose and without fee is hereby
     granted, provided that the above copyright notice appear in all
     copies and that both that copyright notice and this permission
     notice appear in supporting documentation, and that the name of
     Timothy O'Malley  not be used in advertising or publicity
     pertaining to distribution of the software without specific, written
     prior permission.

     Timothy O'Malley DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
     SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     AND FITNESS, IN NO EVENT SHALL Timothy O'Malley BE LIABLE FOR
     ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
     WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
     ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
     PERFORMANCE OF THIS SOFTWARE.


File: python.info,  Node: Execution tracing,  Next: UUencode and UUdecode functions,  Prev: Cookie management,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.5 Execution tracing
------------------------

The *note trace: fd. module contains the following notice:

     portions copyright 2001, Autonomous Zones Industries, Inc., all rights...
     err...  reserved and offered to the public under the terms of the
     Python 2.2 license.
     Author: Zooko O'Whielacronx
     http://zooko.com/
     mailto:zooko@zooko.com

     Copyright 2000, Mojam Media, Inc., all rights reserved.
     Author: Skip Montanaro

     Copyright 1999, Bioreason, Inc., all rights reserved.
     Author: Andrew Dalke

     Copyright 1995-1997, Automatrix, Inc., all rights reserved.
     Author: Skip Montanaro

     Copyright 1991-1995, Stichting Mathematisch Centrum, all rights reserved.


     Permission to use, copy, modify, and distribute this Python software and
     its associated documentation for any purpose without fee is hereby
     granted, provided that the above copyright notice appears in all copies,
     and that both that copyright notice and this permission notice appear in
     supporting documentation, and that the name of neither Automatrix,
     Bioreason or Mojam Media be used in advertising or publicity pertaining to
     distribution of the software without specific, written prior permission.


File: python.info,  Node: UUencode and UUdecode functions,  Next: XML Remote Procedure Calls,  Prev: Execution tracing,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.6 UUencode and UUdecode functions
--------------------------------------

The ‘uu’ codec contains the following notice:

     Copyright 1994 by Lance Ellinghouse
     Cathedral City, California Republic, United States of America.
                            All Rights Reserved
     Permission to use, copy, modify, and distribute this software and its
     documentation for any purpose and without fee is hereby granted,
     provided that the above copyright notice appear in all copies and that
     both that copyright notice and this permission notice appear in
     supporting documentation, and that the name of Lance Ellinghouse
     not be used in advertising or publicity pertaining to distribution
     of the software without specific, written prior permission.
     LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO
     THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
     FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE CENTRUM BE LIABLE
     FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
     OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

     Modified by Jack Jansen, CWI, July 1995:
     - Use binascii module to do the actual line-by-line conversion
       between ascii and binary. This results in a 1000-fold speedup. The C
       version is still 5 times faster, though.
     - Arguments more compliant with Python standard


File: python.info,  Node: XML Remote Procedure Calls,  Next: test_epoll,  Prev: UUencode and UUdecode functions,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.7 XML Remote Procedure Calls
---------------------------------

The *note xmlrpc.client: 12e. module contains the following notice:

         The XML-RPC client interface is

     Copyright (c) 1999-2002 by Secret Labs AB
     Copyright (c) 1999-2002 by Fredrik Lundh

     By obtaining, using, and/or copying this software and/or its
     associated documentation, you agree that you have read, understood,
     and will comply with the following terms and conditions:

     Permission to use, copy, modify, and distribute this software and
     its associated documentation for any purpose and without fee is
     hereby granted, provided that the above copyright notice appears in
     all copies, and that both that copyright notice and this permission
     notice appear in supporting documentation, and that the name of
     Secret Labs AB or the author not be used in advertising or publicity
     pertaining to distribution of the software without specific, written
     prior permission.

     SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
     TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
     ABILITY AND FITNESS.  IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
     BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
     DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
     WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
     ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
     OF THIS SOFTWARE.


File: python.info,  Node: test_epoll,  Next: Select kqueue,  Prev: XML Remote Procedure Calls,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.8 test_epoll
-----------------

The ‘test.test_epoll’ module contains the following notice:

     Copyright (c) 2001-2006 Twisted Matrix Laboratories.

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject to
     the following conditions:

     The above copyright notice and this permission notice shall be
     included in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


File: python.info,  Node: Select kqueue,  Next: SipHash24,  Prev: test_epoll,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.9 Select kqueue
--------------------

The *note select: c1. module contains the following notice for the
kqueue interface:

     Copyright (c) 2000 Doug White, 2006 James Knight, 2007 Christian Heimes
     All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.


File: python.info,  Node: SipHash24,  Next: strtod and dtoa,  Prev: Select kqueue,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.10 SipHash24
-----------------

The file ‘Python/pyhash.c’ contains Marek Majkowski’ implementation of
Dan Bernstein’s SipHash24 algorithm.  It contains the following note:

     <MIT License>
     Copyright (c) 2013  Marek Majkowski <marek@popcount.org>

     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal
     in the Software without restriction, including without limitation the rights
     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     copies of the Software, and to permit persons to whom the Software is
     furnished to do so, subject to the following conditions:

     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.
     </MIT License>

     Original location:
        https://github.com/majek/csiphash/

     Solution inspired by code from:
        Samuel Neves (supercop/crypto_auth/siphash24/little)
        djb (supercop/crypto_auth/siphash24/little2)
        Jean-Philippe Aumasson (https://131002.net/siphash/siphash24.c)


File: python.info,  Node: strtod and dtoa,  Next: OpenSSL<2>,  Prev: SipHash24,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.11 strtod and dtoa
-----------------------

The file ‘Python/dtoa.c’, which supplies C functions dtoa and strtod for
conversion of C doubles to and from strings, is derived from the file of
the same name by David M. Gay, currently available from
‘https://web.archive.org/web/20220517033456/http://www.netlib.org/fp/dtoa.c’.
The original file, as retrieved on March 16, 2009, contains the
following copyright and licensing notice:

     /****************************************************************
      *
      * The author of this software is David M. Gay.
      *
      * Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
      *
      * Permission to use, copy, modify, and distribute this software for any
      * purpose without fee is hereby granted, provided that this entire notice
      * is included in all copies of any software which is or includes a copy
      * or modification of this software and in all copies of the supporting
      * documentation for such software.
      *
      * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
      * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
      * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
      * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
      *
      ***************************************************************/


File: python.info,  Node: OpenSSL<2>,  Next: expat,  Prev: strtod and dtoa,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.12 OpenSSL
---------------

The modules *note hashlib: 68, *note posix: ad. and *note ssl: d0. use
the OpenSSL library for added performance if made available by the
operating system.  Additionally, the Windows and macOS installers for
Python may include a copy of the OpenSSL libraries, so we include a copy
of the OpenSSL license here.  For the OpenSSL 3.0 release, and later
releases derived from that, the Apache License v2 applies:

                                   Apache License
                             Version 2.0, January 2004
                          https://www.apache.org/licenses/

     TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

     1. Definitions.

        "License" shall mean the terms and conditions for use, reproduction,
        and distribution as defined by Sections 1 through 9 of this document.

        "Licensor" shall mean the copyright owner or entity authorized by
        the copyright owner that is granting the License.

        "Legal Entity" shall mean the union of the acting entity and all
        other entities that control, are controlled by, or are under common
        control with that entity. For the purposes of this definition,
        "control" means (i) the power, direct or indirect, to cause the
        direction or management of such entity, whether by contract or
        otherwise, or (ii) ownership of fifty percent (50%) or more of the
        outstanding shares, or (iii) beneficial ownership of such entity.

        "You" (or "Your") shall mean an individual or Legal Entity
        exercising permissions granted by this License.

        "Source" form shall mean the preferred form for making modifications,
        including but not limited to software source code, documentation
        source, and configuration files.

        "Object" form shall mean any form resulting from mechanical
        transformation or translation of a Source form, including but
        not limited to compiled object code, generated documentation,
        and conversions to other media types.

        "Work" shall mean the work of authorship, whether in Source or
        Object form, made available under the License, as indicated by a
        copyright notice that is included in or attached to the work
        (an example is provided in the Appendix below).

        "Derivative Works" shall mean any work, whether in Source or Object
        form, that is based on (or derived from) the Work and for which the
        editorial revisions, annotations, elaborations, or other modifications
        represent, as a whole, an original work of authorship. For the purposes
        of this License, Derivative Works shall not include works that remain
        separable from, or merely link (or bind by name) to the interfaces of,
        the Work and Derivative Works thereof.

        "Contribution" shall mean any work of authorship, including
        the original version of the Work and any modifications or additions
        to that Work or Derivative Works thereof, that is intentionally
        submitted to Licensor for inclusion in the Work by the copyright owner
        or by an individual or Legal Entity authorized to submit on behalf of
        the copyright owner. For the purposes of this definition, "submitted"
        means any form of electronic, verbal, or written communication sent
        to the Licensor or its representatives, including but not limited to
        communication on electronic mailing lists, source code control systems,
        and issue tracking systems that are managed by, or on behalf of, the
        Licensor for the purpose of discussing and improving the Work, but
        excluding communication that is conspicuously marked or otherwise
        designated in writing by the copyright owner as "Not a Contribution."

        "Contributor" shall mean Licensor and any individual or Legal Entity
        on behalf of whom a Contribution has been received by Licensor and
        subsequently incorporated within the Work.

     2. Grant of Copyright License. Subject to the terms and conditions of
        this License, each Contributor hereby grants to You a perpetual,
        worldwide, non-exclusive, no-charge, royalty-free, irrevocable
        copyright license to reproduce, prepare Derivative Works of,
        publicly display, publicly perform, sublicense, and distribute the
        Work and such Derivative Works in Source or Object form.

     3. Grant of Patent License. Subject to the terms and conditions of
        this License, each Contributor hereby grants to You a perpetual,
        worldwide, non-exclusive, no-charge, royalty-free, irrevocable
        (except as stated in this section) patent license to make, have made,
        use, offer to sell, sell, import, and otherwise transfer the Work,
        where such license applies only to those patent claims licensable
        by such Contributor that are necessarily infringed by their
        Contribution(s) alone or by combination of their Contribution(s)
        with the Work to which such Contribution(s) was submitted. If You
        institute patent litigation against any entity (including a
        cross-claim or counterclaim in a lawsuit) alleging that the Work
        or a Contribution incorporated within the Work constitutes direct
        or contributory patent infringement, then any patent licenses
        granted to You under this License for that Work shall terminate
        as of the date such litigation is filed.

     4. Redistribution. You may reproduce and distribute copies of the
        Work or Derivative Works thereof in any medium, with or without
        modifications, and in Source or Object form, provided that You
        meet the following conditions:

        (a) You must give any other recipients of the Work or
            Derivative Works a copy of this License; and

        (b) You must cause any modified files to carry prominent notices
            stating that You changed the files; and

        (c) You must retain, in the Source form of any Derivative Works
            that You distribute, all copyright, patent, trademark, and
            attribution notices from the Source form of the Work,
            excluding those notices that do not pertain to any part of
            the Derivative Works; and

        (d) If the Work includes a "NOTICE" text file as part of its
            distribution, then any Derivative Works that You distribute must
            include a readable copy of the attribution notices contained
            within such NOTICE file, excluding those notices that do not
            pertain to any part of the Derivative Works, in at least one
            of the following places: within a NOTICE text file distributed
            as part of the Derivative Works; within the Source form or
            documentation, if provided along with the Derivative Works; or,
            within a display generated by the Derivative Works, if and
            wherever such third-party notices normally appear. The contents
            of the NOTICE file are for informational purposes only and
            do not modify the License. You may add Your own attribution
            notices within Derivative Works that You distribute, alongside
            or as an addendum to the NOTICE text from the Work, provided
            that such additional attribution notices cannot be construed
            as modifying the License.

        You may add Your own copyright statement to Your modifications and
        may provide additional or different license terms and conditions
        for use, reproduction, or distribution of Your modifications, or
        for any such Derivative Works as a whole, provided Your use,
        reproduction, and distribution of the Work otherwise complies with
        the conditions stated in this License.

     5. Submission of Contributions. Unless You explicitly state otherwise,
        any Contribution intentionally submitted for inclusion in the Work
        by You to the Licensor shall be under the terms and conditions of
        this License, without any additional terms or conditions.
        Notwithstanding the above, nothing herein shall supersede or modify
        the terms of any separate license agreement you may have executed
        with Licensor regarding such Contributions.

     6. Trademarks. This License does not grant permission to use the trade
        names, trademarks, service marks, or product names of the Licensor,
        except as required for reasonable and customary use in describing the
        origin of the Work and reproducing the content of the NOTICE file.

     7. Disclaimer of Warranty. Unless required by applicable law or
        agreed to in writing, Licensor provides the Work (and each
        Contributor provides its Contributions) on an "AS IS" BASIS,
        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
        implied, including, without limitation, any warranties or conditions
        of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
        PARTICULAR PURPOSE. You are solely responsible for determining the
        appropriateness of using or redistributing the Work and assume any
        risks associated with Your exercise of permissions under this License.

     8. Limitation of Liability. In no event and under no legal theory,
        whether in tort (including negligence), contract, or otherwise,
        unless required by applicable law (such as deliberate and grossly
        negligent acts) or agreed to in writing, shall any Contributor be
        liable to You for damages, including any direct, indirect, special,
        incidental, or consequential damages of any character arising as a
        result of this License or out of the use or inability to use the
        Work (including but not limited to damages for loss of goodwill,
        work stoppage, computer failure or malfunction, or any and all
        other commercial damages or losses), even if such Contributor
        has been advised of the possibility of such damages.

     9. Accepting Warranty or Additional Liability. While redistributing
        the Work or Derivative Works thereof, You may choose to offer,
        and charge a fee for, acceptance of support, warranty, indemnity,
        or other liability obligations and/or rights consistent with this
        License. However, in accepting such obligations, You may act only
        on Your own behalf and on Your sole responsibility, not on behalf
        of any other Contributor, and only if You agree to indemnify,
        defend, and hold each Contributor harmless for any liability
        incurred by, or claims asserted against, such Contributor by reason
        of your accepting any such warranty or additional liability.

     END OF TERMS AND CONDITIONS


File: python.info,  Node: expat,  Next: libffi,  Prev: OpenSSL<2>,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.13 expat
-------------

The *note pyexpat: 126. extension is built using an included copy of the
expat sources unless the build is configured ‘--with-system-expat’:

     Copyright (c) 1998, 1999, 2000 Thai Open Source Software Center Ltd
                                    and Clark Cooper

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject to
     the following conditions:

     The above copyright notice and this permission notice shall be included
     in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


File: python.info,  Node: libffi,  Next: zlib<3>,  Prev: expat,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.14 libffi
--------------

The ‘_ctypes’ C extension underlying the *note ctypes: 2a. module is
built using an included copy of the libffi sources unless the build is
configured ‘--with-system-libffi’:

     Copyright (c) 1996-2008  Red Hat, Inc and others.

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject to
     the following conditions:

     The above copyright notice and this permission notice shall be included
     in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
     HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     DEALINGS IN THE SOFTWARE.


File: python.info,  Node: zlib<3>,  Next: cfuhash,  Prev: libffi,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.15 zlib
------------

The *note zlib: 133. extension is built using an included copy of the
zlib sources if the zlib version found on the system is too old to be
used for the build:

     Copyright (C) 1995-2011 Jean-loup Gailly and Mark Adler

     This software is provided 'as-is', without any express or implied
     warranty.  In no event will the authors be held liable for any damages
     arising from the use of this software.

     Permission is granted to anyone to use this software for any purpose,
     including commercial applications, and to alter it and redistribute it
     freely, subject to the following restrictions:

     1. The origin of this software must not be misrepresented; you must not
        claim that you wrote the original software. If you use this software
        in a product, an acknowledgment in the product documentation would be
        appreciated but is not required.

     2. Altered source versions must be plainly marked as such, and must not be
        misrepresented as being the original software.

     3. This notice may not be removed or altered from any source distribution.

     Jean-loup Gailly        Mark Adler
     jloup@gzip.org          madler@alumni.caltech.edu


File: python.info,  Node: cfuhash,  Next: libmpdec,  Prev: zlib<3>,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.16 cfuhash
---------------

The implementation of the hash table used by the *note tracemalloc: ff.
is based on the cfuhash project:

     Copyright (c) 2005 Don Owens
     All rights reserved.

     This code is released under the BSD license:

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:

       * Redistributions of source code must retain the above copyright
         notice, this list of conditions and the following disclaimer.

       * Redistributions in binary form must reproduce the above
         copyright notice, this list of conditions and the following
         disclaimer in the documentation and/or other materials provided
         with the distribution.

       * Neither the name of the author nor the names of its
         contributors may be used to endorse or promote products derived
         from this software without specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     OF THE POSSIBILITY OF SUCH DAMAGE.


File: python.info,  Node: libmpdec,  Next: W3C C14N test suite,  Prev: cfuhash,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.17 libmpdec
----------------

The ‘_decimal’ C extension underlying the *note decimal: 36. module is
built using an included copy of the libmpdec library unless the build is
configured ‘--with-system-libmpdec’:

     Copyright (c) 2008-2020 Stefan Krah. All rights reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:

     1. Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.


File: python.info,  Node: W3C C14N test suite,  Next: mimalloc,  Prev: libmpdec,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.18 W3C C14N test suite
---------------------------

The C14N 2.0 test suite in the *note test: e2. package
(‘Lib/test/xmltestdata/c14n-20/’) was retrieved from the W3C website at
‘https://www.w3.org/TR/xml-c14n2-testcases/’ and is distributed under
the 3-clause BSD license:

     Copyright (c) 2013 W3C(R) (MIT, ERCIM, Keio, Beihang),
     All Rights Reserved.

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:

     * Redistributions of works must retain the original copyright notice,
       this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the original copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
     * Neither the name of the W3C nor the names of its contributors may be
       used to endorse or promote products derived from this work without
       specific prior written permission.

     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


File: python.info,  Node: mimalloc,  Next: asyncio<12>,  Prev: W3C C14N test suite,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.19 mimalloc
----------------

MIT License:

     Copyright (c) 2018-2021 Microsoft Corporation, Daan Leijen

     Permission is hereby granted, free of charge, to any person obtaining a copy
     of this software and associated documentation files (the "Software"), to deal
     in the Software without restriction, including without limitation the rights
     to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     copies of the Software, and to permit persons to whom the Software is
     furnished to do so, subject to the following conditions:

     The above copyright notice and this permission notice shall be included in all
     copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.


File: python.info,  Node: asyncio<12>,  Next: Global Unbounded Sequences GUS,  Prev: mimalloc,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.20 asyncio
---------------

Parts of the *note asyncio: a. module are incorporated from uvloop
0.16(1), which is distributed under the MIT license:

     Copyright (c) 2015-2021 MagicStack Inc.  http://magic.io

     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     "Software"), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject to
     the following conditions:

     The above copyright notice and this permission notice shall be
     included in all copies or substantial portions of the Software.

     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

   ---------- Footnotes ----------

   (1) https://github.com/MagicStack/uvloop/tree/v0.16.0


File: python.info,  Node: Global Unbounded Sequences GUS,  Prev: asyncio<12>,  Up: Licenses and Acknowledgements for Incorporated Software

16.3.21 Global Unbounded Sequences (GUS)
----------------------------------------

The file ‘Python/qsbr.c’ is adapted from FreeBSD’s “Global Unbounded
Sequences” safe memory reclamation scheme in subr_smr.c(1).  The file is
distributed under the 2-Clause BSD License:

     Copyright (c) 2019,2020 Jeffrey Roberson <jeff@FreeBSD.org>

     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
     1. Redistributions of source code must retain the above copyright
        notice unmodified, this list of conditions, and the following
        disclaimer.
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

     THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   ---------- Footnotes ----------

   (1) 
https://github.com/freebsd/freebsd-src/blob/main/sys/kern/subr_smr.c


File: python.info,  Node: Python Module Index,  Next: Index,  Prev: History and License,  Up: Top

Python Module Index
*******************

* Menu:

* __future__: 0. Future statement definitions
* __main__: 1. The environment where top-level code is run. Covers
                        command-line interfaces, import-time
                        behavior, and ''__name__ ==
                        '__main__'''.
* _thread: 2. Low-level threading API.
* _tkinter: 3. A binary module that contains the low-level interface
                        to Tcl/Tk.
* abc: 4. Abstract base classes according to :pep:'3119'.
* aifc: 5. Removed in 3.13.
* argparse: 6. Command-line option and argument parsing library.
* array: 7. Space efficient arrays of uniformly typed numeric
                        values.
* ast: 8. Abstract Syntax Tree classes and manipulation.
* asynchat: 9. Removed in 3.12.
* asyncio: a. Asynchronous I/O.
* asyncore: b. Removed in 3.12.
* atexit: c. Register and execute cleanup functions.
* audioop: d. Removed in 3.13.
* base64: e. RFC 4648: Base16, Base32, Base64 Data
                        Encodings; Base85 and Ascii85
* bdb: f. Debugger framework.
* binascii: 10. Tools for converting between binary and various ASCII-
                        encoded binary representations.
* bisect: 11. Array bisection algorithms for binary searching.
* builtins: 12. The module that provides the built-in namespace.
* bz2: 13. Interfaces for bzip2 compression and decompression.
* calendar: 14. Functions for working with calendars, including
                        some emulation of the Unix cal program.
* cgi: 15. Removed in 3.13.
* cgitb: 16. Removed in 3.13.
* chunk: 17. Removed in 3.13.
* cmath: 18. Mathematical functions for complex numbers.
* cmd: 19. Build line-oriented command interpreters.
* code: 1a. Facilities to implement read-eval-print loops.
* codecs: 1b. Encode and decode data and streams.
* codeop: 1c. Compile (possibly incomplete) Python code.
* collections: 1d. Container datatypes
* collections.abc: 1e. Abstract base classes for containers
* colorsys: 1f. Conversion functions between RGB and other color
                        systems.
* compileall: 20. Tools for byte-compiling all Python source files in a
                        directory tree.
* concurrent.futures: 21. Execute computations concurrently using threads or
                        processes.
* configparser: 22. Configuration file parser.
* contextlib: 23. Utilities for with-statement contexts.
* contextvars: 24. Context Variables
* copy: 25. Shallow and deep copy operations.
* copyreg: 26. Register pickle support functions.
* cProfile: 27.
* crypt: 28. Removed in 3.13.
* csv: 29. Write and read tabular data to and from delimited
                        files.
* ctypes: 2a. A foreign function library for Python.
* curses: 2b. An interface to the curses library, providing
                        portable terminal handling.
* curses.ascii: 2c. Constants and set-membership functions for ASCII
                        characters.
* curses.panel: 2d. A panel stack extension that adds depth to curses
                        windows.
* curses.textpad: 2e. Emacs-like input editing in a curses window.
* dataclasses: 2f. Generate special methods on user-defined classes.
* datetime: 30. Basic date and time types.
* dbm: 31. Interfaces to various Unix "database" formats.
* dbm.dumb: 32. Portable implementation of the simple DBM interface.
* dbm.gnu: 33. GNU database manager
* dbm.ndbm: 34. The New Database Manager
* dbm.sqlite3: 35. SQLite backend for dbm
* decimal: 36. Implementation of the General Decimal Arithmetic
                        Specification.
* difflib: 37. Helpers for computing differences between objects.
* dis: 38. Disassembler for Python bytecode.
* distutils: 39. Removed in 3.12.
* doctest: 3a. Test pieces of code within docstrings.
* email: 3b. Package supporting the parsing,
                        manipulating, and generating email messages.
* email.charset: 3c. Character Sets
* email.contentmanager: 3d. Storing and Retrieving Content from MIME Parts
* email.encoders: 3e. Encoders for email message payloads.
* email.errors: 3f. The exception classes used by the email package.
* email.generator: 40. Generate flat text email messages from a message
                        structure.
* email.header: 41. Representing non-ASCII headers
* email.headerregistry: 42. Automatic Parsing of headers based on the field name
* email.iterators: 43. Iterate over a message object tree.
* email.message: 44. The base class representing email messages.
* email.mime: 45. Build MIME messages.
* email.mime.application: 46.
* email.mime.audio: 47.
* email.mime.base: 48.
* email.mime.image: 49.
* email.mime.message: 4a.
* email.mime.multipart: 4b.
* email.mime.nonmultipart: 4c.
* email.mime.text: 4d.
* email.parser: 4e. Parse flat text email messages to produce a message
                        object structure.
* email.policy: 4f. Controlling the parsing and generating of messages
* email.utils: 50. Miscellaneous email package utilities.
* encodings: 51. Encodings package
* encodings.idna: 52. Internationalized Domain Names implementation
* encodings.mbcs: 53. Windows ANSI codepage
* encodings.utf_8_sig: 54. UTF-8 codec with BOM signature
* ensurepip: 55. Bootstrapping the "pip" installer into an existing
                        Python installation or virtual environment.
* enum: 56. Implementation of an enumeration class.
* errno: 57. Standard errno system symbols.
* faulthandler: 58. Dump the Python traceback.
* fcntl: 59. The fcntl() and ioctl() system calls.
* filecmp: 5a. Compare files efficiently.
* fileinput: 5b. Loop over standard input or a list of files.
* fnmatch: 5c. Unix shell style filename pattern matching.
* fractions: 5d. Rational numbers.
* ftplib: 5e. FTP protocol client (requires sockets).
* functools: 5f. Higher-order functions and operations on callable
                        objects.
* gc: 60. Interface to the cycle-detecting garbage collector.
* getopt: 61. Portable parser for command line options; support both
                        short and long option names.
* getpass: 62. Portable reading of passwords and retrieval of the
                        userid.
* gettext: 63. Multilingual internationalization services.
* glob: 64. Unix shell style pathname pattern expansion.
* graphlib: 65. Functionality to operate with graph-like structures
* grp: 66. The group database (getgrnam() and friends).
* gzip: 67. Interfaces for gzip compression and decompression
                        using file objects.
* hashlib: 68. Secure hash and message digest algorithms.
* heapq: 69. Heap queue algorithm (a.k.a. priority queue).
* hmac: 6a. Keyed-Hashing for Message Authentication (HMAC)
                        implementation
* html: 6b. Helpers for manipulating HTML.
* html.entities: 6c. Definitions of HTML general entities.
* html.parser: 6d. A simple parser that can handle HTML and XHTML.
* http: 6e. HTTP status codes and messages
* http.client: 6f. HTTP and HTTPS protocol client (requires sockets).
* http.cookiejar: 70. Classes for automatic handling of HTTP cookies.
* http.cookies: 71. Support for HTTP state management (cookies).
* http.server: 72. HTTP server and request handlers.
* idlelib: 73. Implementation package for the IDLE shell/editor.
* imaplib: 74. IMAP4 protocol client (requires sockets).
* imghdr: 75. Removed in 3.13.
* imp: 76. Removed in 3.12.
* importlib: 77. The implementation of the import machinery.
* importlib.abc: 78. Abstract base classes related to import
* importlib.machinery: 79. Importers and path hooks
* importlib.metadata: 7a. Accessing package metadata
* importlib.resources: 7b. Package resource reading, opening, and
                        access
* importlib.resources.abc: 7c. Abstract base classes for resources
* importlib.util: 7d. Utility code for importers
* inspect: 7e. Extract information and source code from live objects.
* io: 7f. Core tools for working with streams.
* ipaddress: 80. IPv4/IPv6 manipulation library.
* itertools: 81. Functions creating iterators for efficient looping.
* json: 82. Encode and decode the JSON format.
* json.tool: 83. A command line to validate and pretty-print JSON.
* keyword: 84. Test whether a string is a keyword in Python.
* linecache: 85. Provides random access to individual lines from text
                        files.
* locale: 86. Internationalization services.
* logging: 87. Flexible event logging system for applications.
* logging.config: 88. Configuration of the logging module.
* logging.handlers: 89. Handlers for the logging module.
* lzma: 8a. A Python wrapper for the liblzma compression library.
* mailbox: 8b. Manipulate mailboxes in various formats
* mailcap: 8c. Removed in 3.13.
* marshal: 8d. Convert Python objects to streams of bytes and back
                        (with different constraints).
* math: 8e. Mathematical functions (sin() etc.).
* mimetypes: 8f. Mapping of filename extensions to MIME types.
* mmap: 90. Interface to memory-mapped files for Unix and Windows.
* modulefinder: 91. Find modules used by a script.
* msilib: 92. Removed in 3.13.
* msvcrt: 93. Miscellaneous useful routines from the MS VC++
                        runtime.
* multiprocessing: 94. Process-based parallelism.
* multiprocessing.connection: 95. API for dealing with sockets.
* multiprocessing.dummy: 96. Dumb wrapper around threading.
* multiprocessing.managers: 97. Share data between process with shared objects.
* multiprocessing.pool: 98. Create pools of processes.
* multiprocessing.shared_memory: 99. Provides shared memory for direct access
                                 across processes.
* multiprocessing.sharedctypes: 9a. Allocate ctypes objects from shared memory.
* netrc: 9b. Loading of .netrc files.
* nis: 9c. Removed in 3.13.
* nntplib: 9d. Removed in 3.13.
* numbers: 9e. Numeric abstract base classes (Complex,
                        Real, Integral, etc.).
* operator: 9f. Functions corresponding to the standard operators.
* optparse: a0. Command-line option parsing library.
* os: a1. Miscellaneous operating system interfaces.
* os.path: a2. Operations on pathnames.
* ossaudiodev: a3. Removed in 3.13.
* pathlib: a4. Object-oriented filesystem paths
* pdb: a5. The Python debugger for interactive interpreters.
* pickle: a6. Convert Python objects to streams of bytes and back.
* pickletools: a7. Contains extensive comments about the pickle protocols
                        and pickle-machine opcodes, as well as some
                        useful functions.
* pipes: a8. Removed in 3.13.
* pkgutil: a9. Utilities for the import system.
* platform: aa. Retrieves as much platform identifying data as
                        possible.
* plistlib: ab. Generate and parse Apple plist files.
* poplib: ac. POP3 protocol client (requires sockets).
* posix: ad. The most common POSIX system calls (normally used via
                        module os).
* pprint: ae. Data pretty printer.
* profile: af. Python source profiler.
* pstats: b0. Statistics object for use with the profiler.
* pty: b1. Pseudo-Terminal Handling for Unix.
* pwd: b2. The password database (getpwnam() and friends).
* py_compile: b3. Generate byte-code files from Python source files.
* pyclbr: b4. Supports information extraction for a Python module
                        browser.
* pydoc: b5. Documentation generator and online help system.
* queue: b6. A synchronized queue class.
* quopri: b7. Encode and decode files using the MIME quoted-
                        printable encoding.
* random: b8. Generate pseudo-random numbers with various common
                        distributions.
* re: b9. Regular expression operations.
* readline: ba. GNU readline support for Python.
* reprlib: bb. Alternate repr() implementation with size limits.
* resource: bc. An interface to provide resource usage information on
                        the current process.
* rlcompleter: bd. Python identifier completion, suitable for the
                        GNU readline library.
* runpy: be. Locate and run Python modules without importing them
                        first.
* sched: bf. General purpose event scheduler.
* secrets: c0. Generate secure random numbers for managing secrets.
* select: c1. Wait for I/O completion on multiple streams.
* selectors: c2. High-level I/O multiplexing.
* shelve: c3. Python object persistence.
* shlex: c4. Simple lexical analysis for Unix shell-like languages.
* shutil: c5. High-level file operations, including copying.
* signal: c6. Set handlers for asynchronous events.
* site: c7. Module responsible for site-specific configuration.
* sitecustomize: c8.
* smtpd: c9. Removed in 3.12.
* smtplib: ca. SMTP protocol client (requires sockets).
* sndhdr: cb. Removed in 3.13.
* socket: cc. Low-level networking interface.
* socketserver: cd. A framework for network servers.
* spwd: ce. Removed in 3.13.
* sqlite3: cf. A DB-API 2.0 implementation using SQLite 3.x.
* ssl: d0. TLS/SSL wrapper for socket objects
* stat: d1. Utilities for interpreting the results of
                        os.stat(), os.lstat() and os.fstat().
* statistics: d2. Mathematical statistics functions
* string: d3. Common string operations.
* stringprep: d4. String preparation, as per RFC 3453
* struct: d5. Interpret bytes as packed binary data.
* subprocess: d6. Subprocess management.
* sunau: d7. Removed in 3.13.
* symtable: d8. Interface to the compiler's internal symbol tables.
* sys: d9. Access system-specific parameters and functions.
* sys.monitoring: da. Access and control event monitoring
* sysconfig: db. Python's configuration information
* syslog: dc. An interface to the Unix syslog library routines.
* tabnanny: dd. Tool for detecting white space related problems in
                        Python source files in a directory tree.
* tarfile: de. Read and write tar-format archive files.
* telnetlib: df. Removed in 3.13.
* tempfile: e0. Generate temporary files and directories.
* termios: e1. POSIX style tty control.
* test: e2. Regression tests package containing the testing suite
                        for Python.
* test.regrtest: e3. Drives the regression test suite.
* test.support: e4. Support for Python's regression test suite.
* test.support.bytecode_helper: e5. Support tools for testing correct bytecode
                                generation.
* test.support.import_helper: e6. Support for import tests.
* test.support.os_helper: e7. Support for os tests.
* test.support.script_helper: e8. Support for Python's script execution tests.
* test.support.socket_helper: e9. Support for socket tests.
* test.support.threading_helper: ea. Support for threading tests.
* test.support.warnings_helper: eb. Support for warnings tests.
* textwrap: ec. Text wrapping and filling
* threading: ed. Thread-based parallelism.
* time: ee. Time access and conversions.
* timeit: ef. Measure the execution time of small code snippets.
* tkinter: f0. Interface to Tcl/Tk for graphical user interfaces
* tkinter.colorchooser: f1. Color choosing dialog
* tkinter.commondialog: f2. Tkinter base class for dialogs
* tkinter.dnd: f3. Tkinter drag-and-drop interface
* tkinter.filedialog: f4. Dialog classes for file selection
* tkinter.font: f5. Tkinter font-wrapping class
* tkinter.messagebox: f6. Various types of alert dialogs
* tkinter.scrolledtext: f7. Text widget with a vertical scroll bar.
* tkinter.simpledialog: f8. Simple dialog windows
* tkinter.ttk: f9. Tk themed widget set
* token: fa. Constants representing terminal nodes of the parse
                        tree.
* tokenize: fb. Lexical scanner for Python source code.
* tomllib: fc. Parse TOML files.
* trace: fd. Trace or track Python statement execution.
* traceback: fe. Print or retrieve a stack traceback.
* tracemalloc: ff. Trace memory allocations.
* tty: 100. Utility functions that perform common terminal control
                        operations.
* turtle: 101. An educational framework for simple graphics
                        applications
* turtledemo: 102. A viewer for example turtle scripts
* types: 103. Names for built-in types.
* typing: 104. Support for type hints (see :pep:'484').
* unicodedata: 105. Access the Unicode Database.
* unittest: 106. Unit testing framework for Python.
* unittest.mock: 107. Mock object library.
* urllib: 108.
* urllib.error: 109. Exception classes raised by urllib.request.
* urllib.parse: 10a. Parse URLs into or assemble them from components.
* urllib.request: 10b. Extensible library for opening URLs.
* urllib.response: 10c. Response classes used by urllib.
* urllib.robotparser: 10d. Load a robots.txt file and answer questions about
                        fetchability of other URLs.
* usercustomize: 10e.
* uu: 10f. Removed in 3.13.
* uuid: 110. UUID objects (universally unique identifiers)
                        according to RFC 4122
* venv: 111. Creation of virtual environments.
* warnings: 112. Issue warning messages and control their disposition.
* wave: 113. Provide an interface to the WAV sound format.
* weakref: 114. Support for weak references and weak dictionaries.
* webbrowser: 115. Easy-to-use controller for web browsers.
* winreg: 116. Routines and objects for manipulating the Windows
                        registry.
* winsound: 117. Access to the sound-playing machinery for Windows.
* wsgiref: 118. WSGI Utilities and Reference Implementation.
* wsgiref.handlers: 119. WSGI server/gateway base classes.
* wsgiref.headers: 11a. WSGI response header tools.
* wsgiref.simple_server: 11b. A simple WSGI HTTP server.
* wsgiref.types: 11c. WSGI types for static type checking
* wsgiref.util: 11d. WSGI environment utilities.
* wsgiref.validate: 11e. WSGI conformance checker.
* xdrlib: 11f. Removed in 3.13.
* xml: 120. Package containing XML processing modules
* xml.dom: 121. Document Object Model API for Python.
* xml.dom.minidom: 122. Minimal Document Object Model (DOM) implementation.
* xml.dom.pulldom: 123. Support for building partial DOM trees from SAX
                        events.
* xml.etree.ElementInclude: 124.
* xml.etree.ElementTree: 125. Implementation of the ElementTree API.
* xml.parsers.expat: 126. An interface to the Expat non-validating XML parser.
* xml.parsers.expat.errors: 127.
* xml.parsers.expat.model: 128.
* xml.sax: 129. Package containing SAX2 base classes and convenience
                        functions.
* xml.sax.handler: 12a. Base classes for SAX event handlers.
* xml.sax.saxutils: 12b. Convenience functions and classes for use with SAX.
* xml.sax.xmlreader: 12c. Interface which SAX-compliant XML parsers must
                        implement.
* xmlrpc: 12d. Server and client modules implementing XML-RPC.
* xmlrpc.client: 12e. XML-RPC client access.
* xmlrpc.server: 12f. Basic XML-RPC server implementations.
* zipapp: 130. Manage executable Python zip archives
* zipfile: 131. Read and write ZIP-format archive files.
* zipimport: 132. Support for importing Python modules from ZIP
                        archives.
* zlib: 133. Low-level interface to compression and decompression
                        routines compatible with gzip.
* zoneinfo: 134. IANA time zone support


File: python.info,  Node: Index,  Prev: Python Module Index,  Up: Top

Index
*****

[index]
* Menu:

* _ (underscore); gettext:               GNU gettext API.    (line   32)
* _ (underscore); in numeric literal:    Numeric literals.   (line   13)
* _ (underscore); in numeric literal <1>: Integer literals.  (line   39)
* _ (underscore); in string formatting:  Format specification mini-language.
                                                             (line  124)
* __, identifiers:                       Soft Keywords.      (line   21)
* __abs__() (in module operator):        operator — Standard operators as functions.
                                                             (line   73)
* __abs__() (object method):             Emulating numeric types.
                                                             (line  108)
* __add__() (in module operator):        operator — Standard operators as functions.
                                                             (line   78)
* __add__() (object method):             Emulating numeric types.
                                                             (line   11)
* __aenter__() (object method):          Asynchronous Context Managers.
                                                             (line   14)
* __aexit__() (object method):           Asynchronous Context Managers.
                                                             (line   19)
* __aiter__() (object method):           Asynchronous Iterators.
                                                             (line   14)
* __all__:                               Importing * From a Package.
                                                             (line    6)
* __all__ (module attribute):            The import statement.
                                                             (line   84)
* __all__ (optional module attribute):   The import statement.
                                                             (line   84)
* __all__ (package variable):            Importing Modules<2>.
                                                             (line    9)
* __and__() (enum.Flag method):          Data types.         (line  543)
* __and__() (in module operator):        operator — Standard operators as functions.
                                                             (line   83)
* __and__() (object method):             Emulating numeric types.
                                                             (line   11)
* __anext__() (agen method):             Asynchronous generator-iterator methods.
                                                             (line   10)
* __anext__() (object method):           Asynchronous Iterators.
                                                             (line   18)
* __annotations__ (class attribute):     Special attributes. (line    6)
* __annotations__ (function attribute):  Special writable attributes.
                                                             (line    6)
* __annotations__ (function attribute) <1>: Special writable attributes.
                                                             (line   45)
* __annotations__ (module attribute):    Modules<3>.         (line   21)
* __annotations__ (module attribute) <1>: Other writable attributes on module objects.
                                                             (line   14)
* __annotations__ (type attribute):      Special attributes. (line   43)
* __args__ (genericalias attribute):     Special Attributes of GenericAlias objects.
                                                             (line   15)
* __await__() (object method):           Awaitable Objects.  (line   14)
* __base__ (class attribute):            Special attributes. (line    6)
* __base__ (type attribute):             Special attributes. (line   33)
* __bases__ (class attribute):           Special attributes. (line    6)
* __bases__ (type attribute):            Special attributes. (line   27)
* __bool__() (object method):            Basic customization.
                                                             (line  315)
* __bool__() (object method) <1>:        Emulating container types.
                                                             (line   46)
* __bound__ (typing.TypeVar attribute):  Building generic types and type aliases.
                                                             (line  175)
* __breakpointhook__ (in module sys):    sys — System-specific parameters and functions.
                                                             (line  420)
* __buffer__() (object method):          Emulating buffer types.
                                                             (line   15)
* __builtins__ (function attribute):     Special read-only attributes.
                                                             (line    6)
* __builtins__ (function attribute) <1>: Special read-only attributes.
                                                             (line   10)
* __bytes__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  129)
* __bytes__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  138)
* __bytes__() (object method):           Basic customization.
                                                             (line  144)
* __cached__ (module attribute):         Modules<3>.         (line   21)
* __cached__ (module attribute) <1>:     Import-related attributes on module objects.
                                                             (line  138)
* __call__() (argparse.Action method):   Action classes.     (line   28)
* __call__() (email.headerregistry.HeaderRegistry method): email headerregistry Custom Header Objects.
                                                             (line  389)
* __call__() (enum.EnumType method):     Data types.         (line   20)
* __call__() (in module operator):       operator — Standard operators as functions.
                                                             (line  221)
* __call__() (object method):            Emulating callable objects.
                                                             (line    6)
* __call__() (object method) <1>:        Calls.              (line  157)
* __call__() (weakref.finalize method):  weakref — Weak references.
                                                             (line  293)
* __callback__ (weakref.ref attribute):  weakref — Weak references.
                                                             (line  124)
* __cause__ (BaseException attribute):   Exception context.  (line    9)
* __cause__ (exception attribute):       The raise statement.
                                                             (line   30)
* __cause__ (exception attribute) <1>:   Exception context.  (line    6)
* __cause__ (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   44)
* __ceil__() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  185)
* __ceil__() (object method):            Emulating numeric types.
                                                             (line  138)
* __class__ (instance attribute):        Special attributes<2>.
                                                             (line    6)
* __class__ (method cell):               Creating the class object.
                                                             (line    6)
* __class__ (module attribute):          Customizing module attribute access.
                                                             (line    6)
* __class__ (module attribute) <1>:      Customizing module attribute access.
                                                             (line   24)
* __class__ (object attribute):          Special attributes<2>.
                                                             (line    6)
* __class__ (unittest.mock.Mock attribute): The Mock Class.  (line  558)
* __class_getitem__() (object class method): Emulating generic types.
                                                             (line   32)
* __classcell__ (class namespace entry): Creating the class object.
                                                             (line    6)
* __closure__ (function attribute):      Special read-only attributes.
                                                             (line    6)
* __closure__ (function attribute) <1>:  Special read-only attributes.
                                                             (line   22)
* __code__ (function attribute):         Special writable attributes.
                                                             (line    6)
* __code__ (function attribute) <1>:     Special writable attributes.
                                                             (line   36)
* __code__ (function object attribute):  Code Objects.       (line    6)
* __complex__() (object method):         Emulating numeric types.
                                                             (line  116)
* __concat__() (in module operator):     operator — Standard operators as functions.
                                                             (line  176)
* __constraints__ (typing.TypeVar attribute): Building generic types and type aliases.
                                                             (line  184)
* __contains__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  179)
* __contains__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  301)
* __contains__() (enum.EnumType method): Data types.         (line   65)
* __contains__() (enum.Flag method):     Data types.         (line  481)
* __contains__() (in module operator):   operator — Standard operators as functions.
                                                             (line  181)
* __contains__() (mailbox.Mailbox method): Mailbox objects.  (line  202)
* __contains__() (object method):        Emulating container types.
                                                             (line  154)
* __context__ (BaseException attribute): Exception context.  (line    9)
* __context__ (exception attribute):     The raise statement.
                                                             (line   30)
* __context__ (exception attribute) <1>: Exception context.  (line    6)
* __context__ (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   48)
* __contravariant__ (typing.TypeVar attribute): Building generic types and type aliases.
                                                             (line  163)
* __copy__() (copy protocol):            copy — Shallow and deep copy operations.
                                                             (line   80)
* __covariant__ (typing.TypeVar attribute): Building generic types and type aliases.
                                                             (line  159)
* __debug__:                             The assert statement.
                                                             (line   21)
* __debug__ (built-in variable):         Built-in Constants. (line   67)
* __deepcopy__() (copy protocol):        copy — Shallow and deep copy operations.
                                                             (line   80)
* __default__ (typing.ParamSpec attribute): Building generic types and type aliases.
                                                             (line  427)
* __default__ (typing.TypeVar attribute): Building generic types and type aliases.
                                                             (line  194)
* __default__ (typing.TypeVarTuple attribute): Building generic types and type aliases.
                                                             (line  326)
* __defaults__ (function attribute):     Special writable attributes.
                                                             (line    6)
* __defaults__ (function attribute) <1>: Special writable attributes.
                                                             (line   30)
* __del__() (io.IOBase method):          I/O Base Classes.   (line  163)
* __del__() (object method):             Basic customization.
                                                             (line   52)
* __delattr__() (object method):         Customizing attribute access.
                                                             (line   68)
* __delete__() (object method):          Implementing Descriptors.
                                                             (line   42)
* __delitem__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  226)
* __delitem__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  335)
* __delitem__() (in module operator):    operator — Standard operators as functions.
                                                             (line  191)
* __delitem__() (mailbox.Mailbox method): Mailbox objects.   (line   76)
* __delitem__() (mailbox.MH method):     MH objects.         (line   79)
* __delitem__() (object method):         Emulating container types.
                                                             (line  113)
* __dict__ (class attribute):            Special attributes. (line    6)
* __dict__ (function attribute):         Special writable attributes.
                                                             (line    6)
* __dict__ (function attribute) <1>:     Special writable attributes.
                                                             (line   40)
* __dict__ (instance attribute):         Special attributes<2>.
                                                             (line    6)
* __dict__ (module attribute):           Module dictionaries.
                                                             (line    8)
* __dict__ (module attribute) <1>:       Module dictionaries.
                                                             (line    8)
* __dict__ (module attribute) <2>:       Module Objects.     (line   49)
* __dict__ (object attribute):           Special attributes<2>.
                                                             (line   10)
* __dict__ (type attribute):             Special attributes. (line   22)
* __dir__ (module attribute):            Customizing module attribute access.
                                                             (line    6)
* __dir__() (enum.Enum method):          Data types.         (line  200)
* __dir__() (enum.EnumType method):      Data types.         (line   78)
* __dir__() (module method):             Customizing module attribute access.
                                                             (line    6)
* __dir__() (object method):             Customizing attribute access.
                                                             (line   77)
* __dir__() (unittest.mock.Mock method): The Mock Class.     (line  298)
* __displayhook__ (in module sys):       sys — System-specific parameters and functions.
                                                             (line  420)
* __divmod__() (object method):          Emulating numeric types.
                                                             (line   11)
* __doc__ (class attribute):             Special attributes. (line    6)
* __doc__ (definition attribute):        Special Attributes. (line   26)
* __doc__ (function attribute):          Special writable attributes.
                                                             (line    6)
* __doc__ (function attribute) <1>:      Special writable attributes.
                                                             (line   12)
* __doc__ (method attribute):            Instance methods.   (line    9)
* __doc__ (method attribute) <1>:        Instance methods.   (line   18)
* __doc__ (module attribute):            Modules<3>.         (line   21)
* __doc__ (module attribute) <1>:        Other writable attributes on module objects.
                                                             (line    9)
* __doc__ (module attribute) <2>:        Module Objects.     (line   26)
* __doc__ (type attribute):              Special attributes. (line   39)
* __enter__() (contextmanager method):   Context Manager Types.
                                                             (line   12)
* __enter__() (object method):           With Statement Context Managers.
                                                             (line   22)
* __enter__() (winreg.PyHKEY method):    Registry Handle Objects.
                                                             (line   52)
* __eq__() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  150)
* __eq__() (email.header.Header method): email header Internationalized headers.
                                                             (line  168)
* __eq__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __eq__() (instance method):            Comparisons<2>.     (line   50)
* __eq__() (memoryview method):          Memory Views.       (line  111)
* __eq__() (object method):              Basic customization.
                                                             (line  178)
* __excepthook__ (in module sys):        sys — System-specific parameters and functions.
                                                             (line  420)
* __excepthook__ (in module threading):  Reference<2>.       (line   65)
* __exit__() (contextmanager method):    Context Manager Types.
                                                             (line   32)
* __exit__() (object method):            With Statement Context Managers.
                                                             (line   28)
* __exit__() (winreg.PyHKEY method):     Registry Handle Objects.
                                                             (line   52)
* __file__ (module attribute):           Modules<3>.         (line   21)
* __file__ (module attribute) <1>:       Import-related attributes on module objects.
                                                             (line  136)
* __file__ (module attribute) <2>:       Module Objects.     (line   26)
* __file__ (module attribute) <3>:       Module Objects.     (line  103)
* __firstlineno__ (class attribute):     Special attributes. (line    6)
* __firstlineno__ (type attribute):      Special attributes. (line   72)
* __float__() (object method):           Emulating numeric types.
                                                             (line  116)
* __floor__() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  175)
* __floor__() (object method):           Emulating numeric types.
                                                             (line  138)
* __floordiv__() (in module operator):   operator — Standard operators as functions.
                                                             (line   88)
* __floordiv__() (object method):        Emulating numeric types.
                                                             (line   11)
* __format__:                            Built-in Functions. (line  786)
* __format__() (datetime.date method):   date Objects.       (line  307)
* __format__() (datetime.datetime method): datetime Objects. (line  759)
* __format__() (datetime.time method):   time Objects.       (line  227)
* __format__() (enum.Enum method):       Data types.         (line  359)
* __format__() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  202)
* __format__() (ipaddress.IPv4Address method): Address objects.
                                                             (line  195)
* __format__() (ipaddress.IPv6Address method): Address objects.
                                                             (line  327)
* __format__() (object method):          Basic customization.
                                                             (line  151)
* __fspath__() (os.PathLike method):     Process Parameters. (line  125)
* __func__ (method attribute):           Instance methods.   (line    9)
* __func__ (method attribute) <1>:       Instance methods.   (line   15)
* __future__:                            Glossary.           (line  648)
* __future__; future statement:          Future statements.  (line    6)
* __ge__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __ge__() (instance method):            Comparisons<2>.     (line   50)
* __ge__() (object method):              Basic customization.
                                                             (line  178)
* __get__() (object method):             Implementing Descriptors.
                                                             (line   15)
* __getattr__ (module attribute):        Customizing module attribute access.
                                                             (line    6)
* __getattr__() (module method):         Customizing module attribute access.
                                                             (line    6)
* __getattr__() (object method):         Customizing attribute access.
                                                             (line   10)
* __getattribute__() (object method):    Customizing attribute access.
                                                             (line   32)
* __getitem__() (email.headerregistry.HeaderRegistry method): email headerregistry Custom Header Objects.
                                                             (line  384)
* __getitem__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  189)
* __getitem__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  310)
* __getitem__() (enum.EnumType method):  Data types.         (line   86)
* __getitem__() (in module operator):    operator — Standard operators as functions.
                                                             (line  196)
* __getitem__() (mailbox.Mailbox method): Mailbox objects.   (line  147)
* __getitem__() (mapping object method): Special method names.
                                                             (line    6)
* __getitem__() (object method):         Emulating container types.
                                                             (line   83)
* __getitem__() (re.Match method):       Match Objects.      (line   89)
* __getnewargs__() (object method):      Pickling Class Instances.
                                                             (line   47)
* __getnewargs_ex__() (object method):   Pickling Class Instances.
                                                             (line   29)
* __getstate__() (copy protocol):        Handling Stateful Objects.
                                                             (line    6)
* __getstate__() (object method):        Pickling Class Instances.
                                                             (line   61)
* __globals__ (function attribute):      Special read-only attributes.
                                                             (line    6)
* __globals__ (function attribute) <1>:  Special read-only attributes.
                                                             (line   16)
* __gt__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __gt__() (instance method):            Comparisons<2>.     (line   50)
* __gt__() (object method):              Basic customization.
                                                             (line  178)
* __hash__() (object method):            Basic customization.
                                                             (line  235)
* __iadd__() (in module operator):       In-place Operators. (line   36)
* __iadd__() (object method):            Emulating numeric types.
                                                             (line   77)
* __iand__() (in module operator):       In-place Operators. (line   41)
* __iand__() (object method):            Emulating numeric types.
                                                             (line   77)
* __iconcat__() (in module operator):    In-place Operators. (line   46)
* __ifloordiv__() (in module operator):  In-place Operators. (line   52)
* __ifloordiv__() (object method):       Emulating numeric types.
                                                             (line   77)
* __ilshift__() (in module operator):    In-place Operators. (line   57)
* __ilshift__() (object method):         Emulating numeric types.
                                                             (line   77)
* __imatmul__() (in module operator):    In-place Operators. (line   72)
* __imatmul__() (object method):         Emulating numeric types.
                                                             (line   77)
* __imod__() (in module operator):       In-place Operators. (line   62)
* __imod__() (object method):            Emulating numeric types.
                                                             (line   77)
* __import__() (in module importlib):    Functions<12>.      (line    6)
* __imul__() (in module operator):       In-place Operators. (line   67)
* __imul__() (object method):            Emulating numeric types.
                                                             (line   77)
* __index__() (in module operator):      operator — Standard operators as functions.
                                                             (line   93)
* __index__() (object method):           Emulating numeric types.
                                                             (line  124)
* __infer_variance__ (typing.TypeVar attribute): Building generic types and type aliases.
                                                             (line  168)
* __init__() (asyncio.Future method):    Future and Task private constructors.
                                                             (line   17)
* __init__() (asyncio.Task method):      Future and Task private constructors.
                                                             (line   23)
* __init__() (difflib.HtmlDiff method):  difflib — Helpers for computing deltas.
                                                             (line   92)
* __init__() (enum.Enum method):         Data types.         (line  264)
* __init__() (logging.Handler method):   Handler Objects.    (line   13)
* __init__() (logging.logging.Formatter method): Formatters. (line   13)
* __init__() (object method):            Basic customization.
                                                             (line   36)
* __init_subclass__() (enum.Enum method): Data types.        (line  277)
* __init_subclass__() (object class method): Customizing class creation.
                                                             (line   13)
* __instancecheck__() (type method):     Customizing instance and subclass checks.
                                                             (line   15)
* __int__() (object method):             Emulating numeric types.
                                                             (line  116)
* __interactivehook__ (in module sys):   sys — System-specific parameters and functions.
                                                             (line 1173)
* __inv__() (in module operator):        operator — Standard operators as functions.
                                                             (line  102)
* __invert__() (in module operator):     operator — Standard operators as functions.
                                                             (line  102)
* __invert__() (object method):          Emulating numeric types.
                                                             (line  108)
* __ior__() (in module operator):        In-place Operators. (line   79)
* __ior__() (object method):             Emulating numeric types.
                                                             (line   77)
* __ipow__() (in module operator):       In-place Operators. (line   84)
* __ipow__() (object method):            Emulating numeric types.
                                                             (line   77)
* __irshift__() (in module operator):    In-place Operators. (line   89)
* __irshift__() (object method):         Emulating numeric types.
                                                             (line   77)
* __isub__() (in module operator):       In-place Operators. (line   94)
* __isub__() (object method):            Emulating numeric types.
                                                             (line   77)
* __iter__() (container method):         Iterator Types.     (line   14)
* __iter__() (enum.EnumType method):     Data types.         (line   94)
* __iter__() (iterator method):          Iterator Types.     (line   29)
* __iter__() (mailbox.Mailbox method):   Mailbox objects.    (line  115)
* __iter__() (object method):            Emulating container types.
                                                             (line  127)
* __iter__() (unittest.TestSuite method): Grouping tests.    (line   58)
* __itruediv__() (in module operator):   In-place Operators. (line   99)
* __itruediv__() (object method):        Emulating numeric types.
                                                             (line   77)
* __ixor__() (in module operator):       In-place Operators. (line  104)
* __ixor__() (object method):            Emulating numeric types.
                                                             (line   77)
* __kwdefaults__ (function attribute):   Special writable attributes.
                                                             (line    6)
* __kwdefaults__ (function attribute) <1>: Special writable attributes.
                                                             (line   52)
* __le__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __le__() (instance method):            Comparisons<2>.     (line   50)
* __le__() (object method):              Basic customization.
                                                             (line  178)
* __len__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  175)
* __len__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  297)
* __len__() (enum.EnumType method):      Data types.         (line  101)
* __len__() (mailbox.Mailbox method):    Mailbox objects.    (line  207)
* __len__() (mapping object method):     Basic customization.
                                                             (line  317)
* __len__() (object method):             Emulating container types.
                                                             (line   44)
* __length_hint__() (object method):     Emulating container types.
                                                             (line   59)
* __loader__ (module attribute):         Modules<3>.         (line   21)
* __loader__ (module attribute) <1>:     Import-related attributes on module objects.
                                                             (line   98)
* __loader__ (module attribute) <2>:     Module Objects.     (line   26)
* __lshift__() (in module operator):     operator — Standard operators as functions.
                                                             (line  110)
* __lshift__() (object method):          Emulating numeric types.
                                                             (line   11)
* __lt__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __lt__() (instance method):            Comparisons<2>.     (line   50)
* __lt__() (object method):              Basic customization.
                                                             (line  178)
* __matmul__() (in module operator):     operator — Standard operators as functions.
                                                             (line  125)
* __matmul__() (object method):          Emulating numeric types.
                                                             (line   11)
* __members__ (enum.EnumType attribute): Data types.         (line  108)
* __missing__():                         Mapping Types — dict.
                                                             (line  115)
* __missing__() (collections.defaultdict method): defaultdict objects.
                                                             (line   28)
* __missing__() (object method):         Emulating container types.
                                                             (line  122)
* __mod__() (in module operator):        operator — Standard operators as functions.
                                                             (line  115)
* __mod__() (object method):             Emulating numeric types.
                                                             (line   11)
* __module__ (class attribute):          Special attributes. (line    6)
* __module__ (definition attribute):     Special Attributes. (line   22)
* __module__ (function attribute):       Special writable attributes.
                                                             (line    6)
* __module__ (function attribute) <1>:   Special writable attributes.
                                                             (line   26)
* __module__ (method attribute):         Instance methods.   (line    9)
* __module__ (method attribute) <1>:     Instance methods.   (line   28)
* __module__ (type attribute):           Special attributes. (line   18)
* __module__ (typing.NewType attribute): Other special directives.
                                                             (line  118)
* __module__ (typing.TypeAliasType attribute): Building generic types and type aliases.
                                                             (line  513)
* __mro__ (type attribute):              Special attributes. (line   80)
* __mro_entries__() (object method):     Resolving MRO entries.
                                                             (line    6)
* __mul__() (in module operator):        operator — Standard operators as functions.
                                                             (line  120)
* __mul__() (object method):             Emulating numeric types.
                                                             (line   11)
* __mutable_keys__ (typing.TypedDict attribute): Other special directives.
                                                             (line  458)
* __name__ (class attribute):            Special attributes. (line    6)
* __name__ (definition attribute):       Special Attributes. (line   10)
* __name__ (function attribute):         Special writable attributes.
                                                             (line    6)
* __name__ (function attribute) <1>:     Special writable attributes.
                                                             (line   16)
* __name__ (method attribute):           Instance methods.   (line    9)
* __name__ (method attribute) <1>:       Instance methods.   (line   24)
* __name__ (module attribute):           Modules<3>.         (line   21)
* __name__ (module attribute) <1>:       Import-related attributes on module objects.
                                                             (line   37)
* __name__ (module attribute) <2>:       Module Objects.     (line   26)
* __name__ (module attribute) <3>:       Module Objects.     (line   67)
* __name__ (property attribute):         Built-in Functions. (line 1671)
* __name__ (type attribute):             Special attributes. (line   10)
* __name__ (typing.NewType attribute):   Other special directives.
                                                             (line  122)
* __name__ (typing.ParamSpec attribute): Building generic types and type aliases.
                                                             (line  423)
* __name__ (typing.TypeAliasType attribute): Building generic types and type aliases.
                                                             (line  505)
* __name__ (typing.TypeVar attribute):   Building generic types and type aliases.
                                                             (line  155)
* __name__ (typing.TypeVarTuple attribute): Building generic types and type aliases.
                                                             (line  322)
* __ne__() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  155)
* __ne__() (email.header.Header method): email header Internationalized headers.
                                                             (line  173)
* __ne__() (in module operator):         operator — Standard operators as functions.
                                                             (line   24)
* __ne__() (instance method):            Comparisons<2>.     (line   50)
* __ne__() (object method):              Basic customization.
                                                             (line  178)
* __neg__() (in module operator):        operator — Standard operators as functions.
                                                             (line  132)
* __neg__() (object method):             Emulating numeric types.
                                                             (line  108)
* __new__() (enum.Enum method):          Data types.         (line  307)
* __new__() (object method):             Basic customization.
                                                             (line    6)
* __next__() (csv.csvreader method):     Reader Objects.     (line    9)
* __next__() (generator method):         Generator-iterator methods.
                                                             (line   12)
* __next__() (iterator method):          Iterator Types.     (line   37)
* __not__() (in module operator):        operator — Standard operators as functions.
                                                             (line   49)
* __notes__ (BaseException attribute):   Base classes.       (line   58)
* __notes__ (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   66)
* __objclass__ (object attribute):       Implementing Descriptors.
                                                             (line   50)
* __optional_keys__ (typing.TypedDict attribute): Other special directives.
                                                             (line  409)
* __or__() (enum.Flag method):           Data types.         (line  536)
* __or__() (in module operator):         operator — Standard operators as functions.
                                                             (line  137)
* __or__() (object method):              Emulating numeric types.
                                                             (line   11)
* __origin__ (genericalias attribute):   Special Attributes of GenericAlias objects.
                                                             (line    8)
* __package__ (module attribute):        Modules<3>.         (line   21)
* __package__ (module attribute) <1>:    Import-related attributes on module objects.
                                                             (line   55)
* __package__ (module attribute) <2>:    Module Objects.     (line   26)
* __parameters__ (genericalias attribute): Special Attributes of GenericAlias objects.
                                                             (line   24)
* __path__ (module attribute):           Modules<3>.         (line   21)
* __path__ (module attribute) <1>:       Import-related attributes on module objects.
                                                             (line  125)
* __pos__() (in module operator):        operator — Standard operators as functions.
                                                             (line  142)
* __pos__() (object method):             Emulating numeric types.
                                                             (line  108)
* __post_init__() (in module dataclasses): Post-init processing.
                                                             (line    6)
* __pow__() (in module operator):        operator — Standard operators as functions.
                                                             (line  147)
* __pow__() (object method):             Emulating numeric types.
                                                             (line   11)
* __prepare__ (metaclass method):        Preparing the class namespace.
                                                             (line    6)
* __PYVENV_LAUNCHER__:                   PyConfig.           (line  183)
* __PYVENV_LAUNCHER__ <1>:               PyConfig.           (line  699)
* __qualname__ (definition attribute):   Special Attributes. (line   15)
* __qualname__ (function attribute):     Special writable attributes.
                                                             (line   20)
* __qualname__ (type attribute):         Special attributes. (line   14)
* __radd__() (object method):            Emulating numeric types.
                                                             (line   41)
* __rand__() (object method):            Emulating numeric types.
                                                             (line   41)
* __rdivmod__() (object method):         Emulating numeric types.
                                                             (line   41)
* __readonly_keys__ (typing.TypedDict attribute): Other special directives.
                                                             (line  450)
* __reduce__() (object method):          Pickling Class Instances.
                                                             (line  124)
* __reduce_ex__() (object method):       Pickling Class Instances.
                                                             (line  180)
* __release_buffer__() (object method):  Emulating buffer types.
                                                             (line   24)
* __replace__() (replace protocol):      copy — Shallow and deep copy operations.
                                                             (line   98)
* __repr__() (enum.Enum method):         Data types.         (line  324)
* __repr__() (multiprocessing.managers.BaseProxy method): Proxy Objects.
                                                             (line  144)
* __repr__() (netrc.netrc method):       netrc Objects.      (line   16)
* __repr__() (object method):            Basic customization.
                                                             (line  112)
* __required_keys__ (typing.TypedDict attribute): Other special directives.
                                                             (line  405)
* __reversed__() (enum.EnumType method): Data types.         (line  113)
* __reversed__() (object method):        Emulating container types.
                                                             (line  134)
* __rfloordiv__() (object method):       Emulating numeric types.
                                                             (line   41)
* __rlshift__() (object method):         Emulating numeric types.
                                                             (line   41)
* __rmatmul__() (object method):         Emulating numeric types.
                                                             (line   41)
* __rmod__() (object method):            Emulating numeric types.
                                                             (line   41)
* __rmul__() (object method):            Emulating numeric types.
                                                             (line   41)
* __ror__() (object method):             Emulating numeric types.
                                                             (line   41)
* __round__() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  191)
* __round__() (object method):           Emulating numeric types.
                                                             (line  138)
* __rpow__() (object method):            Emulating numeric types.
                                                             (line   41)
* __rrshift__() (object method):         Emulating numeric types.
                                                             (line   41)
* __rshift__() (in module operator):     operator — Standard operators as functions.
                                                             (line  152)
* __rshift__() (object method):          Emulating numeric types.
                                                             (line   11)
* __rsub__() (object method):            Emulating numeric types.
                                                             (line   41)
* __rtruediv__() (object method):        Emulating numeric types.
                                                             (line   41)
* __rxor__() (object method):            Emulating numeric types.
                                                             (line   41)
* __self__ (method attribute):           Instance methods.   (line    9)
* __self__ (method attribute) <1>:       Instance methods.   (line   11)
* __set__() (object method):             Implementing Descriptors.
                                                             (line   33)
* __set_name__() (object method):        Customizing class creation.
                                                             (line   47)
* __setattr__() (object method):         Customizing attribute access.
                                                             (line   53)
* __setitem__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  204)
* __setitem__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  321)
* __setitem__() (in module operator):    operator — Standard operators as functions.
                                                             (line  205)
* __setitem__() (mailbox.Mailbox method): Mailbox objects.   (line   89)
* __setitem__() (mailbox.Maildir method): Maildir objects.   (line  193)
* __setitem__() (object method):         Emulating container types.
                                                             (line  104)
* __setstate__() (copy protocol):        Handling Stateful Objects.
                                                             (line    6)
* __setstate__() (object method):        Pickling Class Instances.
                                                             (line   88)
* __slots__:                             Glossary.           (line 1507)
* __spec__ (module attribute):           Modules<3>.         (line   21)
* __spec__ (module attribute) <1>:       Import-related attributes on module objects.
                                                             (line   46)
* __static_attributes__ (class attribute): Special attributes.
                                                             (line    6)
* __static_attributes__ (type attribute): Special attributes.
                                                             (line   65)
* __stderr__ (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1876)
* __stdin__ (in module sys):             sys — System-specific parameters and functions.
                                                             (line 1876)
* __stdout__ (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1876)
* __str__() (datetime.date method):      date Objects.       (line  280)
* __str__() (datetime.datetime method):  datetime Objects.   (line  729)
* __str__() (datetime.time method):      time Objects.       (line  217)
* __str__() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  145)
* __str__() (email.header.Header method): email header Internationalized headers.
                                                             (line  157)
* __str__() (email.headerregistry.Address method): email headerregistry Custom Header Objects.
                                                             (line  446)
* __str__() (email.headerregistry.Group method): email headerregistry Custom Header Objects.
                                                             (line  481)
* __str__() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line   95)
* __str__() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  101)
* __str__() (enum.Enum method):          Data types.         (line  342)
* __str__() (multiprocessing.managers.BaseProxy method): Proxy Objects.
                                                             (line  148)
* __str__() (object method):             Basic customization.
                                                             (line  129)
* __sub__() (in module operator):        operator — Standard operators as functions.
                                                             (line  157)
* __sub__() (object method):             Emulating numeric types.
                                                             (line   11)
* __subclasscheck__() (type method):     Customizing instance and subclass checks.
                                                             (line   21)
* __subclasses__() (type method):        Special methods.    (line   15)
* __subclasshook__() (abc.ABCMeta method): abc — Abstract Base Classes.
                                                             (line   92)
* __supertype__ (typing.NewType attribute): Other special directives.
                                                             (line  126)
* __suppress_context__ (BaseException attribute): Exception context.
                                                             (line    9)
* __suppress_context__ (exception attribute): Exception context.
                                                             (line    6)
* __suppress_context__ (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   61)
* __test__ (module attribute):           Which Docstrings Are Examined?.
                                                             (line    9)
* __total__ (typing.TypedDict attribute): Other special directives.
                                                             (line  380)
* __traceback__ (BaseException attribute): Base classes.     (line   44)
* __traceback__ (exception attribute):   The raise statement.
                                                             (line    6)
* __truediv__() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  540)
* __truediv__() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  139)
* __truediv__() (in module operator):    operator — Standard operators as functions.
                                                             (line  162)
* __truediv__() (object method):         Emulating numeric types.
                                                             (line   11)
* __trunc__() (object method):           Emulating numeric types.
                                                             (line  138)
* __type_params__ (class attribute):     Special attributes. (line    6)
* __type_params__ (definition attribute): Special Attributes.
                                                             (line   31)
* __type_params__ (function attribute):  Special writable attributes.
                                                             (line    6)
* __type_params__ (function attribute) <1>: Special writable attributes.
                                                             (line   56)
* __type_params__ (type attribute):      Special attributes. (line   58)
* __type_params__ (typing.TypeAliasType attribute): Building generic types and type aliases.
                                                             (line  521)
* __unpacked__ (genericalias attribute): Special Attributes of GenericAlias objects.
                                                             (line   40)
* __unraisablehook__ (in module sys):    sys — System-specific parameters and functions.
                                                             (line  420)
* __value__ (typing.TypeAliasType attribute): Building generic types and type aliases.
                                                             (line  533)
* __xor__() (enum.Flag method):          Data types.         (line  552)
* __xor__() (in module operator):        operator — Standard operators as functions.
                                                             (line  168)
* __xor__() (object method):             Emulating numeric types.
                                                             (line   11)
* _, identifiers:                        Soft Keywords.      (line   22)
* _add_alias_() (enum.Enum method):      Data types.         (line  381)
* _add_value_alias_() (enum.Enum method): Data types.        (line  394)
* _align_ (ctypes.Structure attribute):  Structured data types.
                                                             (line   87)
* _anonymous_ (ctypes.Structure attribute): Structured data types.
                                                             (line   96)
* _asdict() (collections.somenamedtuple method): namedtuple Factory Function for Tuples with Named Fields.
                                                             (line  110)
* _b_base_ (ctypes._CData attribute):    Data types<2>.      (line   71)
* _b_needsfree_ (ctypes._CData attribute): Data types<2>.    (line   78)
* _callmethod() (multiprocessing.managers.BaseProxy method): Proxy Objects.
                                                             (line   96)
* _CData (class in ctypes):              Data types<2>.      (line    6)
* _CFuncPtr (class in ctypes):           Foreign functions.  (line   22)
* _clear_internal_caches() (in module sys): sys — System-specific parameters and functions.
                                                             (line  194)
* _clear_type_cache() (in module sys):   sys — System-specific parameters and functions.
                                                             (line  182)
* _current_exceptions() (in module sys): sys — System-specific parameters and functions.
                                                             (line  222)
* _current_frames() (in module sys):     sys — System-specific parameters and functions.
                                                             (line  202)
* _debugmallocstats() (in module sys):   sys — System-specific parameters and functions.
                                                             (line  278)
* _emscripten_info (in module sys):      sys — System-specific parameters and functions.
                                                             (line  343)
* _enablelegacywindowsfsencoding() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1782)
* _enter_task() (in module asyncio):     Task lifetime support.
                                                             (line   22)
* _exit() (in module os):                Process Management. (line  120)
* _Feature (class in __future__):        Module Contents<4>. (line   51)
* _field_defaults (collections.somenamedtuple attribute): namedtuple Factory Function for Tuples with Named Fields.
                                                             (line  159)
* _field_types (ast.AST attribute):      Node classes.       (line   39)
* _fields (ast.AST attribute):           Node classes.       (line   22)
* _fields (collections.somenamedtuple attribute): namedtuple Factory Function for Tuples with Named Fields.
                                                             (line  146)
* _fields_ (ctypes.Structure attribute): Structured data types.
                                                             (line   43)
* _flush() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  116)
* _frozen (C struct):                    Importing Modules<2>.
                                                             (line  271)
* _generate_next_value_() (enum.Enum method): Data types.    (line  222)
* _get_child_mock() (unittest.mock.Mock method): The Mock Class.
                                                             (line  307)
* _get_preferred_schemes() (in module sysconfig): Installation path functions.
                                                             (line   41)
* _getframe() (in module sys):           sys — System-specific parameters and functions.
                                                             (line  879)
* _getframemodulename() (in module sys): sys — System-specific parameters and functions.
                                                             (line  894)
* _getvalue() (multiprocessing.managers.BaseProxy method): Proxy Objects.
                                                             (line  137)
* _handle (ctypes.PyDLL attribute):      Loading shared libraries.
                                                             (line  156)
* _ignore_ (enum.Enum attribute):        Data types.         (line  189)
* _incompatible_extension_module_restrictions() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  168)
* _inittab (C struct):                   Importing Modules<2>.
                                                             (line  307)
* _inittab.initfunc (C member):          Importing Modules<2>.
                                                             (line  319)
* _inittab.name (C member):              Importing Modules<2>.
                                                             (line  315)
* _is_gil_enabled() (in module sys):     sys — System-specific parameters and functions.
                                                             (line 1203)
* _is_interned() (in module sys):        sys — System-specific parameters and functions.
                                                             (line 1235)
* _leave_task() (in module asyncio):     Task lifetime support.
                                                             (line   30)
* _length_ (ctypes.Array attribute):     Arrays and pointers.
                                                             (line   18)
* _log (logging.LoggerAdapter attribute): LoggerAdapter Objects.
                                                             (line   34)
* _make() (collections.somenamedtuple class method): namedtuple Factory Function for Tuples with Named Fields.
                                                             (line  101)
* _makeResult() (unittest.TextTestRunner method): Loading and running tests.
                                                             (line  488)
* _missing_() (enum.Enum method):        Data types.         (line  282)
* _name (ctypes.PyDLL attribute):        Loading shared libraries.
                                                             (line  160)
* _name_ (enum.Enum attribute):          Data types.         (line  153)
* _numeric_repr_() (enum.Flag method):   Data types.         (line  572)
* _objects (ctypes._CData attribute):    Data types<2>.      (line   83)
* _order_ (enum.Enum attribute):         Data types.         (line  161)
* _pack_ (ctypes.Structure attribute):   Structured data types.
                                                             (line   79)
* _parse() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   21)
* _Pointer (class in ctypes):            Arrays and pointers.
                                                             (line   39)
* _Py_c_diff (C function):               Complex Numbers as C Structures.
                                                             (line   33)
* _Py_c_neg (C function):                Complex Numbers as C Structures.
                                                             (line   39)
* _Py_c_pow (C function):                Complex Numbers as C Structures.
                                                             (line   59)
* _Py_c_prod (C function):               Complex Numbers as C Structures.
                                                             (line   44)
* _Py_c_quot (C function):               Complex Numbers as C Structures.
                                                             (line   50)
* _Py_c_sum (C function):                Complex Numbers as C Structures.
                                                             (line   27)
* _Py_InitializeMain (C function):       Multi-Phase Initialization Private Provisional API.
                                                             (line   44)
* _Py_NoneStruct (C var):                Allocating Objects on the Heap.
                                                             (line   57)
* _Py_TPFLAGS_HAVE_VECTORCALL (C macro): PyTypeObject Slots. (line  761)
* _PyBytes_Resize (C function):          Bytes Objects<2>.   (line  182)
* _PyCode_GetExtra (C function):         Extra information.  (line   35)
* _PyCode_SetExtra (C function):         Extra information.  (line   51)
* _PyEval_RequestCodeExtraIndex (C function): Extra information.
                                                             (line   14)
* _PyFrameEvalFunction (C type):         Low-level API.      (line  169)
* _PyInterpreterFrame (C struct):        Internal Frames.    (line    8)
* _PyInterpreterState_GetEvalFrameFunc (C function): Low-level API.
                                                             (line  184)
* _PyInterpreterState_SetEvalFrameFunc (C function): Low-level API.
                                                             (line  194)
* _PyObject_GetDictPtr (C function):     Object Protocol.    (line  286)
* _PyObject_New (C function):            Allocating Objects on the Heap.
                                                             (line    6)
* _PyObject_NewVar (C function):         Allocating Objects on the Heap.
                                                             (line    9)
* _PyObject_Vectorcall (C function):     Object Calling API. (line  198)
* _PyTuple_Resize (C function):          Tuple Objects.      (line  100)
* _register_task() (in module asyncio):  Task lifetime support.
                                                             (line   10)
* _replace() (collections.somenamedtuple method): namedtuple Factory Function for Tuples with Named Fields.
                                                             (line  128)
* _setroot() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   15)
* _SimpleCData (class in ctypes):        Fundamental data types<2>.
                                                             (line    6)
* _structure() (in module email.iterators): email iterators Iterators.
                                                             (line   44)
* _type_ (ctypes._Pointer attribute):    Arrays and pointers.
                                                             (line   54)
* _type_ (ctypes.Array attribute):       Arrays and pointers.
                                                             (line   24)
* _unregister_task() (in module asyncio): Task lifetime support.
                                                             (line   16)
* _value_ (enum.Enum attribute):         Data types.         (line  157)
* _write() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  108)
* _xoptions (in module sys):             sys — System-specific parameters and functions.
                                                             (line 2059)
* - (minus); binary operator:            Binary arithmetic operations.
                                                             (line   83)
* - (minus); binary operator <1>:        Numeric Types — int float complex.
                                                             (line   27)
* - (minus); in doctests:                Option Flags.       (line  163)
* - (minus); in glob-style wildcards:    glob — Unix style pathname pattern expansion.
                                                             (line   10)
* - (minus); in glob-style wildcards <1>: fnmatch — Unix filename pattern matching.
                                                             (line   15)
* - (minus); in printf-style formatting: printf-style String Formatting.
                                                             (line   69)
* - (minus); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   63)
* - (minus); in regular expressions:     Regular Expression Syntax.
                                                             (line  178)
* - (minus); in string formatting:       Format specification mini-language.
                                                             (line   74)
* - (minus); unary operator:             Unary arithmetic and bitwise operations.
                                                             (line   10)
* - (minus); unary operator <1>:         Numeric Types — int float complex.
                                                             (line   27)
* -=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* ->; function annotations:              Function Annotations.
                                                             (line    6)
* ->; function annotations <1>:          Function definitions.
                                                             (line  109)
* , (comma):                             Parenthesized forms.
                                                             (line   20)
* , (comma); argument list:              Slicings.           (line   39)
* , (comma); expression list:            List displays.      (line    6)
* , (comma); expression list <1>:        Set displays.       (line    6)
* , (comma); expression list <2>:        Expression lists.   (line    6)
* , (comma); expression list <3>:        The assert statement.
                                                             (line    6)
* , (comma); expression list <4>:        Class definitions.  (line    6)
* , (comma); identifier list:            The global statement.
                                                             (line    6)
* , (comma); identifier list <1>:        The nonlocal statement.
                                                             (line    6)
* , (comma); import statement:           The import statement.
                                                             (line    6)
* , (comma); in dictionary displays:     Dictionary displays.
                                                             (line    6)
* , (comma); in string formatting:       Format specification mini-language.
                                                             (line  124)
* , (comma); in target list:             Assignment statements.
                                                             (line   35)
* , (comma); parameter list:             Function definitions.
                                                             (line    6)
* , (comma); slicing:                    Slicings.           (line    6)
* , (comma); with statement:             The with statement. (line    6)
* ; (colon); annotated variable:         Annotated assignment statements.
                                                             (line    6)
* ; (colon); compound statement:         The if statement.   (line    6)
* ; (colon); compound statement <1>:     The while statement.
                                                             (line    6)
* ; (colon); compound statement <2>:     The for statement.  (line    6)
* ; (colon); compound statement <3>:     The try statement.  (line    6)
* ; (colon); compound statement <4>:     The with statement. (line    6)
* ; (colon); compound statement <5>:     The match statement.
                                                             (line    6)
* ; (colon); compound statement <6>:     Function definitions.
                                                             (line    6)
* ; (colon); compound statement <7>:     Class definitions.  (line    6)
* ; (colon); function annotations:       Function Annotations.
                                                             (line    6)
* ; (colon); function annotations <1>:   Function definitions.
                                                             (line  109)
* ; (colon); in dictionary expressions:  Dictionary displays.
                                                             (line    6)
* ; (colon); in formatted string literal: String literal concatenation.
                                                             (line   24)
* ; (colon); in formatted string literal <1>: String Methods<2>.
                                                             (line  966)
* ; (colon); in SQL statements:          Cursor objects.     (line   23)
* ; (colon); in string formatting:       Format string syntax.
                                                             (line   13)
* ; (colon); lambda expression:          Lambdas.            (line    6)
* ; (colon); path separator (POSIX):     Miscellaneous System Information.
                                                             (line  137)
* ; (colon); slicing:                    Slicings.           (line    6)
* ; (semicolon):                         Compound statements.
                                                             (line   18)
* ; (semicolon) <1>:                     Miscellaneous System Information.
                                                             (line  137)
* ;= (colon equals):                     Boolean operations. (line   38)
* ! (exclamation mark); in formatted string literal: String Methods<2>.
                                                             (line  966)
* ! (exclamation); in a command interpreter: Cmd Objects.    (line   27)
* ! (exclamation); in curses module:     curses ascii — Utilities for ASCII characters.
                                                             (line  228)
* ! (exclamation); in formatted string literal: String literal concatenation.
                                                             (line   24)
* ! (exclamation); in glob-style wildcards: glob — Unix style pathname pattern expansion.
                                                             (line   10)
* ! (exclamation); in glob-style wildcards <1>: fnmatch — Unix filename pattern matching.
                                                             (line   15)
* ! (exclamation); in string formatting: Format string syntax.
                                                             (line   13)
* ! (exclamation); in struct format strings: Byte Order Size and Alignment.
                                                             (line   13)
* ! (pdb command):                       Debugger commands.  (line  400)
* ! f-string:                            String Methods<2>.  (line  966)
* ! formatted string literal:            String Methods<2>.  (line  966)
* ! patterns:                            Patterns.           (line    6)
* ? (question mark); in a command interpreter: Cmd Objects.  (line   27)
* ? (question mark); in argparse module: nargs.              (line   24)
* ? (question mark); in AST grammar:     Node classes.       (line   22)
* ? (question mark); in glob-style wildcards: glob — Unix style pathname pattern expansion.
                                                             (line   10)
* ? (question mark); in glob-style wildcards <1>: fnmatch — Unix filename pattern matching.
                                                             (line   15)
* ? (question mark); in regular expressions: Regular Expression Syntax.
                                                             (line   81)
* ? (question mark); in SQL statements:  Cursor objects.     (line   23)
* ? (question mark); in struct format strings: Format Characters.
                                                             (line   86)
* ? (question mark); in struct format strings <1>: Format Characters.
                                                             (line  169)
* ? (question mark); replacement character: Error Handlers.  (line   15)
* ??; in regular expressions:            Regular Expression Syntax.
                                                             (line   86)
* ?+; in regular expressions:            Regular Expression Syntax.
                                                             (line   96)
* . (dot); attribute reference:          Attribute references.
                                                             (line    6)
* . (dot); in glob-style wildcards:      glob — Unix style pathname pattern expansion.
                                                             (line   10)
* . (dot); in numeric literal:           Integer literals.   (line   40)
* . (dot); in pathnames:                 Miscellaneous System Information.
                                                             (line  103)
* . (dot); in pathnames <1>:             Miscellaneous System Information.
                                                             (line  131)
* . (dot); in printf-style formatting:   printf-style String Formatting.
                                                             (line   29)
* . (dot); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   23)
* . (dot); in regular expressions:       Regular Expression Syntax.
                                                             (line   46)
* . (dot); in string formatting:         Format string syntax.
                                                             (line   13)
* ..; in pathnames:                      Miscellaneous System Information.
                                                             (line  109)
* ...:                                   Glossary.           (line   10)
* ...; ellipsis literal:                 else Clauses on Loops.
                                                             (line   58)
* ...; ellipsis literal <1>:             Ellipsis.           (line    6)
* ...; ellipsis literal <2>:             Built-in Constants. (line   59)
* ...; ellipsis literal <3>:             The Null Object.    (line   12)
* ...; ellipsis literal <4>:             Annotating callable objects.
                                                             (line   28)
* ...; ellipsis literal <5>:             Annotating tuples.  (line   42)
* ...; ellipsis literal <6>:             Special forms.      (line   78)
* ...; ellipsis literal <7>:             Glossary.           (line   22)
* ...; in doctests:                      Option Flags.       (line   47)
* ...; interpreter prompt:               How are Docstring Examples Recognized?.
                                                             (line   26)
* ...; interpreter prompt <1>:           sys — System-specific parameters and functions.
                                                             (line 1485)
* ...; placeholder:                      textwrap — Text wrapping and filling.
                                                             (line  274)
* ...; placeholder <1>:                  PrettyPrinter Objects.
                                                             (line    6)
* ...; placeholder <2>:                  reprlib — Alternate repr implementation.
                                                             (line   61)
* .ini; file:                            configparser — Configuration file parser.
                                                             (line    8)
* .pdbrc; file:                          Debugger commands.  (line   59)
* ' (single quote); string literal:      Literals.           (line    8)
* '''; string literal:                   String and Bytes literals.
                                                             (line   36)
* " (double quote); string literal:      Literals.           (line    8)
* """; string literal:                   String and Bytes literals.
                                                             (line   36)
* (?; in regular expressions:            Regular Expression Syntax.
                                                             (line  248)
* (?;; in regular expressions:           Regular Expression Syntax.
                                                             (line  287)
* (?!; in regular expressions:           Regular Expression Syntax.
                                                             (line  405)
* (?(; in regular expressions:           Regular Expression Syntax.
                                                             (line  448)
* (?#; in regular expressions:           Regular Expression Syntax.
                                                             (line  394)
* (?<!; in regular expressions:          Regular Expression Syntax.
                                                             (line  439)
* (?<=; in regular expressions:          Regular Expression Syntax.
                                                             (line  411)
* (?=; in regular expressions:           Regular Expression Syntax.
                                                             (line  398)
* (?P<; in regular expressions:          Regular Expression Syntax.
                                                             (line  350)
* (?P=; in regular expressions:          Regular Expression Syntax.
                                                             (line  389)
* () (parentheses); call:                Slicings.           (line   39)
* () (parentheses); class definition:    Class definitions.  (line    6)
* () (parentheses); function definition: Function definitions.
                                                             (line    6)
* () (parentheses); generator expression: Generator expressions.
                                                             (line    6)
* () (parentheses); in assignment target list: Assignment statements.
                                                             (line   35)
* () (parentheses); in printf-style formatting: printf-style String Formatting.
                                                             (line   29)
* () (parentheses); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   23)
* () (parentheses); in regular expressions: Regular Expression Syntax.
                                                             (line  239)
* () (parentheses); tuple display:       Parenthesized forms.
                                                             (line    6)
* [] (square brackets); in assignment target list: Assignment statements.
                                                             (line   35)
* [] (square brackets); in glob-style wildcards: glob — Unix style pathname pattern expansion.
                                                             (line   10)
* [] (square brackets); in glob-style wildcards <1>: fnmatch — Unix filename pattern matching.
                                                             (line   15)
* [] (square brackets); in regular expressions: Regular Expression Syntax.
                                                             (line  171)
* [] (square brackets); in string formatting: Format string syntax.
                                                             (line   13)
* [] (square brackets); list expression: List displays.      (line    6)
* [] (square brackets); subscription:    Subscriptions.      (line    6)
* {} (curly brackets); dictionary expression: Dictionary displays.
                                                             (line    6)
* {} (curly brackets); in formatted string literal: String literal concatenation.
                                                             (line   24)
* {} (curly brackets); in formatted string literal <1>: String Methods<2>.
                                                             (line  966)
* {} (curly brackets); in regular expressions: Regular Expression Syntax.
                                                             (line  115)
* {} (curly brackets); in string formatting: Format string syntax.
                                                             (line   13)
* {} (curly brackets); set expression:   Set displays.       (line    6)
* @ (at); class definition:              Class definitions.  (line   44)
* @ (at); function definition:           Function definitions.
                                                             (line   35)
* @ (at); in struct format strings:      Byte Order Size and Alignment.
                                                             (line   13)
* * (asterisk); function definition:     Function definitions.
                                                             (line   93)
* * (asterisk); import statement:        The import statement.
                                                             (line   80)
* * (asterisk); in argparse module:      nargs.              (line   57)
* * (asterisk); in assignment target list: Assignment statements.
                                                             (line   35)
* * (asterisk); in AST grammar:          Node classes.       (line   22)
* * (asterisk); in expression lists:     Expression lists.   (line   18)
* * (asterisk); in function calls:       Arbitrary Argument Lists.
                                                             (line    6)
* * (asterisk); in function calls <1>:   Calls.              (line   73)
* * (asterisk); in glob-style wildcards: glob — Unix style pathname pattern expansion.
                                                             (line   10)
* * (asterisk); in glob-style wildcards <1>: fnmatch — Unix filename pattern matching.
                                                             (line   15)
* * (asterisk); in printf-style formatting: printf-style String Formatting.
                                                             (line   29)
* * (asterisk); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   23)
* * (asterisk); in regular expressions:  Regular Expression Syntax.
                                                             (line   69)
* *?; in regular expressions:            Regular Expression Syntax.
                                                             (line   86)
* **; function definition:               Function definitions.
                                                             (line   93)
* **; in dictionary displays:            Dictionary displays.
                                                             (line   23)
* **; in function calls:                 Unpacking Argument Lists.
                                                             (line   19)
* **; in function calls <1>:             Calls.              (line  100)
* **; in glob-style wildcards:           glob — Unix style pathname pattern expansion.
                                                             (line   51)
* **=; augmented assignment:             Augmented assignment statements.
                                                             (line    6)
* *+; in regular expressions:            Regular Expression Syntax.
                                                             (line   96)
* *=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* / (slash); function definition:        Function definitions.
                                                             (line   93)
* / (slash); in pathnames:               Miscellaneous System Information.
                                                             (line  115)
* / (slash); in pathnames <1>:           Miscellaneous System Information.
                                                             (line  124)
* //=; augmented assignment:             Augmented assignment statements.
                                                             (line    6)
* /=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* \ (backslash); escape sequence:        String and Bytes literals.
                                                             (line   74)
* \ (backslash); escape sequence <1>:    Error Handlers.     (line   15)
* \ (backslash); in pathnames (Windows): Miscellaneous System Information.
                                                             (line  115)
* \ (backslash); in regular expressions: Regular Expression Syntax.
                                                             (line  156)
* \ (backslash); in regular expressions <1>: Regular Expression Syntax.
                                                             (line  190)
* \ (backslash); in regular expressions <2>: Regular Expression Syntax.
                                                             (line  467)
* \\; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \\; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \a; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \A; in regular expressions:            Regular Expression Syntax.
                                                             (line  479)
* \a; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \b; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \b; in regular expressions:            Regular Expression Syntax.
                                                             (line  483)
* \B; in regular expressions:            Regular Expression Syntax.
                                                             (line  501)
* \b; in regular expressions <1>:        Regular Expression Syntax.
                                                             (line  594)
* \d; in regular expressions:            Regular Expression Syntax.
                                                             (line  517)
* \D; in regular expressions:            Regular Expression Syntax.
                                                             (line  532)
* \f; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \f; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \g; in regular expressions:            Functions<2>.       (line  213)
* \n; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \N; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \N; escape sequence <1>:               Error Handlers.     (line   54)
* \n; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \N; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \r; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \r; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \s; in regular expressions:            Regular Expression Syntax.
                                                             (line  539)
* \S; in regular expressions:            Regular Expression Syntax.
                                                             (line  555)
* \t; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \t; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \u; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \U; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \u; escape sequence <1>:               Error Handlers.     (line   15)
* \U; escape sequence <1>:               Error Handlers.     (line   15)
* \u; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \U; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \v; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \v; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \w; in regular expressions:            Regular Expression Syntax.
                                                             (line  562)
* \W; in regular expressions:            Regular Expression Syntax.
                                                             (line  579)
* \x; escape sequence:                   String and Bytes literals.
                                                             (line   74)
* \x; escape sequence <1>:               Error Handlers.     (line   15)
* \x; in regular expressions:            Regular Expression Syntax.
                                                             (line  594)
* \Z; in regular expressions:            Regular Expression Syntax.
                                                             (line  590)
* &=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* # (hash); comment:                     An Informal Introduction to Python.
                                                             (line   14)
* # (hash); comment <1>:                 Comments.           (line    6)
* # (hash); comment <2>:                 site — Site-specific configuration hook.
                                                             (line   52)
* # (hash); in doctests:                 Option Flags.       (line  164)
* # (hash); in printf-style formatting:  printf-style String Formatting.
                                                             (line   69)
* # (hash); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   63)
* # (hash); in regular expressions:      Flags.              (line  130)
* # (hash); in string formatting:        Format specification mini-language.
                                                             (line   96)
* # (hash); source encoding declaration: Encoding declarations.
                                                             (line    6)
* % (percent); datetime format:          timezone Objects.   (line   71)
* % (percent); datetime format <1>:      Functions<5>.       (line  319)
* % (percent); datetime format <2>:      Functions<5>.       (line  478)
* % (percent); environment variables expansion (Windows): os path — Common pathname manipulations.
                                                             (line  162)
* % (percent); environment variables expansion (Windows) <1>: Functions<13>.
                                                             (line  228)
* % (percent); interpolation in configuration files: Interpolation of values.
                                                             (line   10)
* % (percent); printf-style formatting:  printf-style String Formatting.
                                                             (line    6)
* % (percent); printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line    6)
* %=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* ^ (caret); in curses module:           curses ascii — Utilities for ASCII characters.
                                                             (line  228)
* ^ (caret); in regular expressions:     Regular Expression Syntax.
                                                             (line   53)
* ^ (caret); in regular expressions <1>: Regular Expression Syntax.
                                                             (line  200)
* ^ (caret); in string formatting:       Format specification mini-language.
                                                             (line   44)
* ^ (caret); marker:                     What About Exceptions?.
                                                             (line   93)
* ^ (caret); marker <1>:                 Module-Level Functions<2>.
                                                             (line   36)
* ^=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* + (plus); binary operator:             Binary arithmetic operations.
                                                             (line   74)
* + (plus); binary operator <1>:         Numeric Types — int float complex.
                                                             (line   27)
* + (plus); in argparse module:          nargs.              (line   69)
* + (plus); in doctests:                 Option Flags.       (line  164)
* + (plus); in printf-style formatting:  printf-style String Formatting.
                                                             (line   69)
* + (plus); in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   63)
* + (plus); in regular expressions:      Regular Expression Syntax.
                                                             (line   75)
* + (plus); in string formatting:        Format specification mini-language.
                                                             (line   74)
* + (plus); unary operator:              Unary arithmetic and bitwise operations.
                                                             (line   14)
* + (plus); unary operator <1>:          Numeric Types — int float complex.
                                                             (line   27)
* +?; in regular expressions:            Regular Expression Syntax.
                                                             (line   86)
* ++; in regular expressions:            Regular Expression Syntax.
                                                             (line   96)
* +=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* < (less); in string formatting:        Format specification mini-language.
                                                             (line   44)
* < (less); in struct format strings:    Byte Order Size and Alignment.
                                                             (line   13)
* <<=; augmented assignment:             Augmented assignment statements.
                                                             (line    6)
* <BLANKLINE>:                           Option Flags.       (line   28)
* = (equals); assignment statement:      Assignment statements.
                                                             (line    6)
* = (equals); class definition:          Metaclasses.        (line    6)
* = (equals); for help in debugging using string literals: String literal concatenation.
                                                             (line   24)
* = (equals); for help in debugging using string literals <1>: String Methods<2>.
                                                             (line  965)
* = (equals); function definition:       Function definitions.
                                                             (line   68)
* = (equals); in function calls:         Slicings.           (line   38)
* = (equals); in string formatting:      Format specification mini-language.
                                                             (line   44)
* = (equals); in struct format strings:  Byte Order Size and Alignment.
                                                             (line   13)
* > (greater); in string formatting:     Format specification mini-language.
                                                             (line   44)
* > (greater); in struct format strings: Byte Order Size and Alignment.
                                                             (line   13)
* >>=; augmented assignment:             Augmented assignment statements.
                                                             (line    6)
* >>>:                                   Glossary.           (line    6)
* >>>; interpreter prompt:               How are Docstring Examples Recognized?.
                                                             (line   26)
* >>>; interpreter prompt <1>:           sys — System-specific parameters and functions.
                                                             (line 1485)
* | (vertical bar); in regular expressions: Regular Expression Syntax.
                                                             (line  226)
* |=; augmented assignment:              Augmented assignment statements.
                                                             (line    6)
* ~ (tilde); home directory expansion:   os path — Common pathname manipulations.
                                                             (line  138)
* $ (dollar); environment variables expansion: os path — Common pathname manipulations.
                                                             (line  162)
* $ (dollar); in regular expressions:    Regular Expression Syntax.
                                                             (line   58)
* $ (dollar); in template strings:       Template strings.   (line   13)
* $ (dollar); interpolation in configuration files: Interpolation of values.
                                                             (line   41)
* 0b; integer literal:                   Numeric literals.   (line   14)
* 0o; integer literal:                   Numeric literals.   (line   14)
* 0x; integer literal:                   Numeric literals.   (line   14)
* 2-digit years:                         time — Time access and conversions.
                                                             (line   34)
* A (in module re):                      Flags.              (line   16)
* A_ALTCHARSET (in module curses):       Constants<6>.       (line   65)
* A_ATTRIBUTES (in module curses):       Constants<6>.       (line  126)
* A_BLINK (in module curses):            Constants<6>.       (line   68)
* A_BOLD (in module curses):             Constants<6>.       (line   71)
* A_CHARTEXT (in module curses):         Constants<6>.       (line  129)
* A_COLOR (in module curses):            Constants<6>.       (line  132)
* A_DIM (in module curses):              Constants<6>.       (line   74)
* A_HORIZONTAL (in module curses):       Constants<6>.       (line   99)
* A_INVIS (in module curses):            Constants<6>.       (line   77)
* A_ITALIC (in module curses):           Constants<6>.       (line   80)
* A_LEFT (in module curses):             Constants<6>.       (line  102)
* A_LOW (in module curses):              Constants<6>.       (line  105)
* A_NORMAL (in module curses):           Constants<6>.       (line   83)
* A_PROTECT (in module curses):          Constants<6>.       (line   86)
* A_REVERSE (in module curses):          Constants<6>.       (line   89)
* A_RIGHT (in module curses):            Constants<6>.       (line  108)
* A_STANDOUT (in module curses):         Constants<6>.       (line   93)
* A_TOP (in module curses):              Constants<6>.       (line  111)
* A_UNDERLINE (in module curses):        Constants<6>.       (line   96)
* A_VERTICAL (in module curses):         Constants<6>.       (line  114)
* a2b_base64() (in module binascii):     binascii — Convert between binary and ASCII.
                                                             (line   40)
* a2b_hex() (in module binascii):        binascii — Convert between binary and ASCII.
                                                             (line  144)
* a2b_qp() (in module binascii):         binascii — Convert between binary and ASCII.
                                                             (line   70)
* a2b_uu() (in module binascii):         binascii — Convert between binary and ASCII.
                                                             (line   25)
* a85decode() (in module base64):        Base85 Encodings.   (line   52)
* a85encode() (in module base64):        Base85 Encodings.   (line   28)
* ABC (class in abc):                    abc — Abstract Base Classes.
                                                             (line   27)
* ABCMeta (class in abc):                abc — Abstract Base Classes.
                                                             (line   52)
* ABDAY_1 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_2 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_3 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_4 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_5 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_6 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* ABDAY_7 (in module locale):            locale — Internationalization services.
                                                             (line  239)
* abiflags (in module sys):              sys — System-specific parameters and functions.
                                                             (line   13)
* ABMON_1 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_10 (in module locale):           locale — Internationalization services.
                                                             (line  264)
* ABMON_11 (in module locale):           locale — Internationalization services.
                                                             (line  264)
* ABMON_12 (in module locale):           locale — Internationalization services.
                                                             (line  264)
* ABMON_2 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_3 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_4 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_5 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_6 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_7 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_8 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* ABMON_9 (in module locale):            locale — Internationalization services.
                                                             (line  264)
* abort (C function):                    Process Control.    (line    7)
* ABORT (in module tkinter.messagebox):  tkinter messagebox — Tkinter message prompts.
                                                             (line  147)
* abort_clients() (asyncio.Server method): Server objects.   (line   56)
* abort() (asyncio.Barrier method):      Barrier.            (line   86)
* abort() (asyncio.DatagramTransport method): Datagram Transports.
                                                             (line   20)
* abort() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line    6)
* abort() (ftplib.FTP method):           FTP objects.        (line  151)
* abort() (in module os):                Process Management. (line   16)
* abort() (threading.Barrier method):    Barrier objects.    (line   81)
* ABORTRETRYIGNORE (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  162)
* ABOVE_NORMAL_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line   68)
* above() (curses.panel.Panel method):   Panel Objects.      (line   13)
* abs() (decimal.Context method):        Context objects.    (line  261)
* abs() (in module operator):            operator — Standard operators as functions.
                                                             (line   73)
* absolute_import (in module __future__): Module Contents<4>.
                                                             (line   26)
* absolute() (pathlib.Path method):      Expanding and resolving paths.
                                                             (line   38)
* AbsoluteLinkError:                     tarfile — Read and write tar archive files.
                                                             (line  252)
* AbsolutePathError:                     tarfile — Read and write tar archive files.
                                                             (line  238)
* abspath() (in module os.path):         os path — Common pathname manipulations.
                                                             (line   49)
* abstract base class:                   Glossary.           (line   23)
* AbstractAsyncContextManager (class in contextlib): Utilities.
                                                             (line   19)
* AbstractBasicAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  338)
* AbstractChildWatcher (class in asyncio): Process Watchers. (line   43)
* abstractclassmethod() (in module abc): abc — Abstract Base Classes.
                                                             (line  238)
* AbstractContextManager (class in contextlib): Utilities.   (line    8)
* AbstractDigestAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  377)
* AbstractEventLoop (class in asyncio):  Event loop implementations.
                                                             (line   54)
* AbstractEventLoopPolicy (class in asyncio): Policy Objects.
                                                             (line    8)
* abstractmethod() (in module abc):      abc — Abstract Base Classes.
                                                             (line  161)
* abstractproperty() (in module abc):    abc — Abstract Base Classes.
                                                             (line  282)
* AbstractSet (class in typing):         Aliases to container ABCs in collections abc.
                                                             (line    6)
* abstractstaticmethod() (in module abc): abc — Abstract Base Classes.
                                                             (line  260)
* accept() (multiprocessing.connection.Listener method): Listeners and Clients.
                                                             (line   84)
* accept() (socket.socket method):       Socket Objects.     (line   13)
* access() (in module os):               Files and Directories.
                                                             (line   51)
* accumulate() (in module itertools):    Itertool Functions. (line   10)
* ACK (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   36)
* aclose() (agen method):                Asynchronous generator-iterator methods.
                                                             (line   61)
* aclose() (contextlib.AsyncExitStack method): Utilities.    (line  649)
* aclosing() (in module contextlib):     Utilities.          (line  184)
* acos() (in module cmath):              Trigonometric functions<2>.
                                                             (line    6)
* acos() (in module math):               Trigonometric functions.
                                                             (line    6)
* acosh() (in module cmath):             Hyperbolic functions<2>.
                                                             (line    6)
* acosh() (in module math):              Hyperbolic functions.
                                                             (line    9)
* acquire() (_thread.lock method):       _thread — Low-level threading API.
                                                             (line  145)
* acquire() (asyncio.Condition method):  Condition.          (line   47)
* acquire() (asyncio.Lock method):       Lock.               (line   35)
* acquire() (asyncio.Semaphore method):  Semaphore.          (line   42)
* acquire() (logging.Handler method):    Handler Objects.    (line   26)
* acquire() (multiprocessing.Lock method): Synchronization primitives.
                                                             (line   78)
* acquire() (multiprocessing.RLock method): Synchronization primitives.
                                                             (line  135)
* acquire() (threading.Condition method): Condition objects. (line   85)
* acquire() (threading.Lock method):     Lock objects.       (line   42)
* acquire() (threading.RLock method):    RLock objects.      (line   44)
* acquire() (threading.Semaphore method): Semaphore objects. (line   34)
* ACS_BBSS (in module curses):           Constants<6>.       (line  470)
* ACS_BLOCK (in module curses):          Constants<6>.       (line  473)
* ACS_BOARD (in module curses):          Constants<6>.       (line  476)
* ACS_BSBS (in module curses):           Constants<6>.       (line  479)
* ACS_BSSB (in module curses):           Constants<6>.       (line  482)
* ACS_BSSS (in module curses):           Constants<6>.       (line  485)
* ACS_BTEE (in module curses):           Constants<6>.       (line  488)
* ACS_BULLET (in module curses):         Constants<6>.       (line  491)
* ACS_CKBOARD (in module curses):        Constants<6>.       (line  494)
* ACS_DARROW (in module curses):         Constants<6>.       (line  497)
* ACS_DEGREE (in module curses):         Constants<6>.       (line  500)
* ACS_DIAMOND (in module curses):        Constants<6>.       (line  503)
* ACS_GEQUAL (in module curses):         Constants<6>.       (line  506)
* ACS_HLINE (in module curses):          Constants<6>.       (line  509)
* ACS_LANTERN (in module curses):        Constants<6>.       (line  512)
* ACS_LARROW (in module curses):         Constants<6>.       (line  515)
* ACS_LEQUAL (in module curses):         Constants<6>.       (line  518)
* ACS_LLCORNER (in module curses):       Constants<6>.       (line  521)
* ACS_LRCORNER (in module curses):       Constants<6>.       (line  524)
* ACS_LTEE (in module curses):           Constants<6>.       (line  527)
* ACS_NEQUAL (in module curses):         Constants<6>.       (line  530)
* ACS_PI (in module curses):             Constants<6>.       (line  533)
* ACS_PLMINUS (in module curses):        Constants<6>.       (line  536)
* ACS_PLUS (in module curses):           Constants<6>.       (line  539)
* ACS_RARROW (in module curses):         Constants<6>.       (line  542)
* ACS_RTEE (in module curses):           Constants<6>.       (line  545)
* ACS_S1 (in module curses):             Constants<6>.       (line  548)
* ACS_S3 (in module curses):             Constants<6>.       (line  551)
* ACS_S7 (in module curses):             Constants<6>.       (line  554)
* ACS_S9 (in module curses):             Constants<6>.       (line  557)
* ACS_SBBS (in module curses):           Constants<6>.       (line  560)
* ACS_SBSB (in module curses):           Constants<6>.       (line  563)
* ACS_SBSS (in module curses):           Constants<6>.       (line  566)
* ACS_SSBB (in module curses):           Constants<6>.       (line  569)
* ACS_SSBS (in module curses):           Constants<6>.       (line  572)
* ACS_SSSB (in module curses):           Constants<6>.       (line  575)
* ACS_SSSS (in module curses):           Constants<6>.       (line  578)
* ACS_STERLING (in module curses):       Constants<6>.       (line  581)
* ACS_TTEE (in module curses):           Constants<6>.       (line  584)
* ACS_UARROW (in module curses):         Constants<6>.       (line  587)
* ACS_ULCORNER (in module curses):       Constants<6>.       (line  590)
* ACS_URCORNER (in module curses):       Constants<6>.       (line  593)
* ACS_VLINE (in module curses):          Constants<6>.       (line  596)
* Action (class in argparse):            Action classes.     (line   11)
* action (optparse.Option attribute):    Option attributes.  (line   19)
* ACTIONS (optparse.Option attribute):   Adding new actions. (line   30)
* activate_stack_trampoline() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1748)
* active_children() (in module multiprocessing): Miscellaneous<3>.
                                                             (line    6)
* active_count() (in module threading):  Reference<2>.       (line    8)
* actual() (tkinter.font.Font method):   tkinter font — Tkinter font wrapper.
                                                             (line   47)
* Add (class in ast):                    Expressions<2>.     (line   53)
* add_alias() (in module email.charset): email charset Representing character sets.
                                                             (line  193)
* add_alternative() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  640)
* add_argument_group() (argparse.ArgumentParser method): Argument groups.
                                                             (line    6)
* add_argument() (argparse.ArgumentParser method): The add_argument method.
                                                             (line    6)
* add_attachment() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  652)
* add_cgi_vars() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  134)
* add_charset() (in module email.charset): email charset Representing character sets.
                                                             (line  164)
* add_child_handler() (asyncio.AbstractChildWatcher method): Process Watchers.
                                                             (line   45)
* add_codec() (in module email.charset): email charset Representing character sets.
                                                             (line  202)
* add_cookie_header() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   11)
* add_dll_directory() (in module os):    Process Management. (line   24)
* add_done_callback() (asyncio.Future method): Future Object.
                                                             (line   81)
* add_done_callback() (asyncio.Task method): Task object.    (line  101)
* add_done_callback() (concurrent.futures.Future method): Future Objects.
                                                             (line   66)
* add_fallback() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   28)
* add_flag() (mailbox.Maildir method):   Maildir objects.    (line  129)
* add_flag() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   76)
* add_flag() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   79)
* add_flag() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   78)
* add_folder() (mailbox.Maildir method): Maildir objects.    (line   75)
* add_folder() (mailbox.MH method):      MH objects.         (line   45)
* add_get_handler() (email.contentmanager.ContentManager method): email contentmanager Managing MIME Content.
                                                             (line   75)
* add_handler() (urllib.request.OpenerDirector method): OpenerDirector Objects.
                                                             (line    8)
* add_header() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  260)
* add_header() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  368)
* add_header() (urllib.request.Request method): Request Objects.
                                                             (line   78)
* add_header() (wsgiref.headers.Headers method): wsgiref headers – WSGI response header tools.
                                                             (line   60)
* add_history() (in module readline):    History list.       (line   38)
* add_label() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   55)
* add_mutually_exclusive_group() (argparse.ArgumentParser method): Mutual exclusion.
                                                             (line    6)
* add_note() (BaseException method):     Base classes.       (line   50)
* add_option() (optparse.OptionParser method): Defining options.
                                                             (line   14)
* add_parent() (urllib.request.BaseHandler method): BaseHandler Objects.
                                                             (line   10)
* add_password() (urllib.request.HTTPPasswordMgr method): HTTPPasswordMgr Objects.
                                                             (line    9)
* add_password() (urllib.request.HTTPPasswordMgrWithPriorAuth method): HTTPPasswordMgrWithPriorAuth Objects.
                                                             (line   10)
* add_reader() (asyncio.loop method):    Watching file descriptors.
                                                             (line    6)
* add_related() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  627)
* add_section() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  121)
* add_section() (configparser.RawConfigParser method): RawConfigParser Objects.
                                                             (line   37)
* add_sequence() (mailbox.MHMessage method): MHMessage objects.
                                                             (line   41)
* add_set_handler() (email.contentmanager.ContentManager method): email contentmanager Managing MIME Content.
                                                             (line   80)
* add_signal_handler() (asyncio.loop method): Unix signals.  (line    6)
* add_subparsers() (argparse.ArgumentParser method): Subcommands.
                                                             (line    6)
* add_type() (in module mimetypes):      mimetypes — Map filenames to MIME types.
                                                             (line  120)
* add_type() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line  104)
* add_unredirected_header() (urllib.request.Request method): Request Objects.
                                                             (line   90)
* add_writer() (asyncio.loop method):    Watching file descriptors.
                                                             (line   20)
* add() (decimal.Context method):        Context objects.    (line  265)
* add() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line   81)
* add() (in module operator):            operator — Standard operators as functions.
                                                             (line   78)
* add() (mailbox.Mailbox method):        Mailbox objects.    (line   59)
* add() (mailbox.Maildir method):        Maildir objects.    (line  193)
* add() (pstats.Stats method):           The Stats Class.    (line   49)
* add() (set method):                    Set Types — set frozenset.
                                                             (line  197)
* add() (tarfile.TarFile method):        TarFile Objects.    (line  272)
* add() (tkinter.ttk.Notebook method):   ttk Notebook.       (line    8)
* addAsyncCleanup() (unittest.IsolatedAsyncioTestCase method): Test cases.
                                                             (line  884)
* addaudithook() (in module sys):        sys — System-specific parameters and functions.
                                                             (line   26)
* addch() (curses.window method):        Window Objects.     (line   11)
* addClassCleanup() (unittest.TestCase class method): Test cases.
                                                             (line  805)
* addCleanup() (unittest.TestCase method): Test cases.       (line  766)
* addcomponent() (turtle.Shape method):  Public classes.     (line   66)
* addDuration() (unittest.TestResult method): Loading and running tests.
                                                             (line  435)
* addError() (unittest.TestResult method): Loading and running tests.
                                                             (line  365)
* addExpectedFailure() (unittest.TestResult method): Loading and running tests.
                                                             (line  401)
* addFailure() (unittest.TestResult method): Loading and running tests.
                                                             (line  376)
* addfile() (tarfile.TarFile method):    TarFile Objects.    (line  290)
* addFilter() (logging.Handler method):  Handler Objects.    (line   53)
* addFilter() (logging.Logger method):   Logger Objects.     (line  325)
* addHandler() (logging.Logger method):  Logger Objects.     (line  342)
* addinfourl (class in urllib.response): urllib response — Response classes used by urllib.
                                                             (line   12)
* addition:                              Binary arithmetic operations.
                                                             (line   74)
* addLevelName() (in module logging):    Module-Level Functions.
                                                             (line  128)
* addModuleCleanup() (in module unittest): setUpModule and tearDownModule.
                                                             (line   22)
* addnstr() (curses.window method):      Window Objects.     (line   25)
* AddPackagePath() (in module modulefinder): modulefinder — Find modules used by a script.
                                                             (line   16)
* addr_spec (email.headerregistry.Address attribute): email headerregistry Custom Header Objects.
                                                             (line  440)
* Address (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  402)
* address (email.headerregistry.SingleAddressHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  221)
* address (multiprocessing.connection.Listener attribute): Listeners and Clients.
                                                             (line   99)
* address (multiprocessing.managers.BaseManager attribute): Managers.
                                                             (line  137)
* address_exclude() (ipaddress.IPv4Network method): Network objects.
                                                             (line  160)
* address_exclude() (ipaddress.IPv6Network method): Network objects.
                                                             (line  342)
* address_family (socketserver.BaseServer attribute): Server Objects.
                                                             (line   65)
* address_string() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  335)
* addresses (email.headerregistry.AddressHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  194)
* addresses (email.headerregistry.Group attribute): email headerregistry Custom Header Objects.
                                                             (line  476)
* AddressHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  179)
* addressof() (in module ctypes):        Utility functions.  (line    6)
* AddressValueError:                     Custom Exceptions.  (line    9)
* addshape() (in module turtle):         Settings and special methods.
                                                             (line   71)
* addsitedir() (in module site):         Module contents<6>. (line   52)
* addSkip() (unittest.TestResult method): Loading and running tests.
                                                             (line  393)
* addstr() (curses.window method):       Window Objects.     (line   33)
* addSubTest() (unittest.TestResult method): Loading and running tests.
                                                             (line  419)
* addSuccess() (unittest.TestResult method): Loading and running tests.
                                                             (line  387)
* addTest() (unittest.TestSuite method): Grouping tests.     (line   25)
* addTests() (unittest.TestSuite method): Grouping tests.    (line   29)
* addTypeEqualityFunc() (unittest.TestCase method): Test cases.
                                                             (line  583)
* addUnexpectedSuccess() (unittest.TestResult method): Loading and running tests.
                                                             (line  411)
* adjust_int_max_str_digits() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  742)
* adjusted() (decimal.Decimal method):   Decimal objects.    (line  113)
* adler32() (in module zlib):            zlib — Compression compatible with gzip.
                                                             (line   28)
* AF_ALG (in module socket):             Constants<8>.       (line  263)
* AF_CAN (in module socket):             Constants<8>.       (line  126)
* AF_DIVERT (in module socket):          Constants<8>.       (line  202)
* AF_HYPERV (in module socket):          Constants<8>.       (line  344)
* AF_INET (in module socket):            Constants<8>.       (line   11)
* AF_INET6 (in module socket):           Constants<8>.       (line   11)
* AF_LINK (in module socket):            Constants<8>.       (line  287)
* AF_PACKET (in module socket):          Constants<8>.       (line  212)
* AF_QIPCRTR (in module socket):         Constants<8>.       (line  314)
* AF_RDS (in module socket):             Constants<8>.       (line  234)
* AF_UNIX (in module socket):            Constants<8>.       (line   11)
* AF_UNSPEC (in module socket):          Constants<8>.       (line   21)
* AF_VSOCK (in module socket):           Constants<8>.       (line  274)
* alarm() (in module signal):            Module contents<3>. (line  299)
* ALERT_DESCRIPTION_HANDSHAKE_FAILURE (in module ssl): Constants<9>.
                                                             (line  510)
* ALERT_DESCRIPTION_INTERNAL_ERROR (in module ssl): Constants<9>.
                                                             (line  510)
* AlertDescription (class in ssl):       Constants<9>.       (line  524)
* algorithm (sys.hash_info attribute):   sys — System-specific parameters and functions.
                                                             (line 1053)
* algorithms_available (in module hashlib): Attributes.      (line   17)
* algorithms_guaranteed (in module hashlib): Attributes.     (line    8)
* alias (class in ast):                  Imports.            (line   38)
* alias (pdb command):                   Debugger commands.  (line  372)
* alignment() (in module ctypes):        Utility functions.  (line   14)
* alive (weakref.finalize attribute):    weakref — Weak references.
                                                             (line  310)
* ALL_COMPLETED (in module asyncio):     Waiting primitives. (line   45)
* ALL_COMPLETED (in module concurrent.futures): Module Functions.
                                                             (line   40)
* all_errors (in module ftplib):         Module variables.   (line   27)
* all_features (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  100)
* all_frames (tracemalloc.Filter attribute): Filter.         (line   58)
* all_properties (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  132)
* all_suffixes() (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   57)
* all_tasks() (in module asyncio):       Introspection.      (line   16)
* allocate_lock() (in module _thread):   _thread — Low-level threading API.
                                                             (line   83)
* allocfunc (C type):                    Slot Type typedefs. (line    6)
* ALLOW_MISSING (in module os.path):     os path — Common pathname manipulations.
                                                             (line  428)
* allow_reuse_address (socketserver.BaseServer attribute): Server Objects.
                                                             (line   95)
* allowed_domains() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   65)
* ALT_DIGITS (in module locale):         locale — Internationalization services.
                                                             (line  344)
* alt() (in module curses.ascii):        curses ascii — Utilities for ASCII characters.
                                                             (line  220)
* altsep (in module os):                 Miscellaneous System Information.
                                                             (line  124)
* altzone (in module time):              Timezone Constants. (line    6)
* ALWAYS_EQ (in module test.support):    test support — Utilities for the Python test suite.
                                                             (line  174)
* ALWAYS_TYPED_ACTIONS (optparse.Option attribute): Adding new actions.
                                                             (line   42)
* AmbiguousOptionError:                  Exceptions<10>.     (line   25)
* AMPER (in module token):               token — Constants used with Python parse trees.
                                                             (line  212)
* AMPEREQUAL (in module token):          token — Constants used with Python parse trees.
                                                             (line  278)
* Anchor (class in importlib.resources): importlib resources – Package resource reading opening and access.
                                                             (line   46)
* anchor (pathlib.PurePath attribute):   Methods and properties.
                                                             (line   65)
* And (class in ast):                    Expressions<2>.     (line   86)
* and_() (in module operator):           operator — Standard operators as functions.
                                                             (line   83)
* android_ver() (in module platform):    Android platform.   (line    6)
* AnnAssign (class in ast):              Statements.         (line   41)
* Annotated (in module typing):          Special forms.      (line  289)
* annotated; assignment:                 Annotated assignment statements.
                                                             (line    6)
* annotation:                            Glossary.           (line   37)
* annotation (inspect.Parameter attribute): Introspecting callables with the Signature object.
                                                             (line  221)
* ANNOTATION (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   26)
* annotation; type annotation; type hint: Type Annotation Types — Generic Alias Union.
                                                             (line    6)
* annotations (in module __future__):    Module Contents<4>. (line   47)
* anonymous; function:                   Lambdas.            (line    6)
* answer_challenge() (in module multiprocessing.connection): Listeners and Clients.
                                                             (line   25)
* anticipate_failure() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  455)
* Any (in module typing):                Special types.      (line    9)
* ANY (in module unittest.mock):         ANY.                (line    6)
* ANY_CONTIGUOUS (inspect.BufferFlags attribute): Buffer flags.
                                                             (line   29)
* AnyStr (in module typing):             Special types.      (line   21)
* api_version (in module sys):           sys — System-specific parameters and functions.
                                                             (line 2017)
* apilevel (in module sqlite3):          Module constants.   (line   65)
* apop() (poplib.POP3 method):           POP3 Objects.       (line   42)
* append_history_file() (in module readline): History file.  (line   20)
* append() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  122)
* append() (collections.deque method):   deque objects.      (line   35)
* append() (email.header.Header method): email header Internationalized headers.
                                                             (line   95)
* append() (imaplib.IMAP4 method):       IMAP4 Objects.      (line   33)
* append() (sequence method):            Mutable Sequence Types.
                                                             (line   69)
* append() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   87)
* appendChild() (xml.dom.Node method):   Node Objects.       (line  115)
* appendleft() (collections.deque method): deque objects.    (line   39)
* AppleFrameworkLoader (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  442)
* application_uri() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line   34)
* apply_async() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line   77)
* apply_defaults() (inspect.BoundArguments method): Introspecting callables with the Signature object.
                                                             (line  366)
* apply() (multiprocessing.pool.Pool method): Process Pools. (line   69)
* APRIL (in module calendar):            calendar — General calendar-related functions.
                                                             (line  488)
* architecture() (in module platform):   Cross platform.     (line    6)
* archive (zipimport.zipimporter attribute): zipimporter Objects.
                                                             (line   96)
* AREGTYPE (in module tarfile):          tarfile — Read and write tar archive files.
                                                             (line  277)
* aRepr (in module reprlib):             reprlib — Alternate repr implementation.
                                                             (line   44)
* arg (class in ast):                    Function and class definitions.
                                                             (line   68)
* args (BaseException attribute):        Base classes.       (line   17)
* args (functools.partial attribute):    partial Objects.    (line   15)
* args (inspect.BoundArguments attribute): Introspecting callables with the Signature object.
                                                             (line  351)
* args (pdb command):                    Debugger commands.  (line  262)
* args (subprocess.CompletedProcess attribute): Using the subprocess Module.
                                                             (line  105)
* args (subprocess.Popen attribute):     Popen Objects.      (line  108)
* args (typing.ParamSpec attribute):     Building generic types and type aliases.
                                                             (line  408)
* args_from_interpreter_flags() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  322)
* argtypes (ctypes._CFuncPtr attribute): Foreign functions.  (line   46)
* argument:                              Glossary.           (line   53)
* argument; call semantics:              Slicings.           (line   39)
* argument; difference from parameter:   How can I pass optional or keyword parameters from one function to another?.
                                                             (line   17)
* argument; function definition:         Function definitions.
                                                             (line   68)
* ArgumentDefaultsHelpFormatter (class in argparse): formatter_class.
                                                             (line   10)
* ArgumentError:                         Foreign functions.  (line   93)
* ArgumentError <1>:                     Exceptions<9>.      (line    6)
* ArgumentParser (class in argparse):    ArgumentParser objects.
                                                             (line    6)
* arguments (class in ast):              Function and class definitions.
                                                             (line   49)
* arguments (inspect.BoundArguments attribute): Introspecting callables with the Signature object.
                                                             (line  332)
* ArgumentTypeError:                     Exceptions<9>.      (line   14)
* argv (in module sys):                  sys — System-specific parameters and functions.
                                                             (line   70)
* argv (in module sys) <1>:              Process-wide parameters.
                                                             (line  218)
* argv (in module sys) <2>:              PyConfig.           (line  127)
* arithmetic:                            Numeric Types — int float complex.
                                                             (line   27)
* arithmetic; conversion:                Arithmetic conversions.
                                                             (line    6)
* ArithmeticError:                       Base classes.       (line   72)
* array (class in array):                array — Efficient arrays of numeric values.
                                                             (line   88)
* Array (class in ctypes):               Arrays and pointers.
                                                             (line    6)
* ARRAY() (in module ctypes):            Arrays and pointers.
                                                             (line   31)
* Array() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   51)
* Array() (in module multiprocessing):   Shared ctypes Objects.
                                                             (line   42)
* Array() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  213)
* arrays:                                array — Efficient arrays of numeric values.
                                                             (line    6)
* arraysize (sqlite3.Cursor attribute):  Cursor objects.     (line  172)
* AS pattern, OR pattern, capture pattern, wildcard pattern: Patterns.
                                                             (line    6)
* as_bytes() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  107)
* as_bytes() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  106)
* as_completed() (in module asyncio):    Waiting primitives. (line   60)
* as_completed() (in module concurrent.futures): Module Functions.
                                                             (line   44)
* as_file() (in module importlib.resources): importlib resources – Package resource reading opening and access.
                                                             (line   74)
* as_integer_ratio() (decimal.Decimal method): Decimal objects.
                                                             (line  121)
* as_integer_ratio() (float method):     Additional Methods on Float.
                                                             (line    9)
* as_integer_ratio() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  120)
* as_integer_ratio() (int method):       Additional Methods on Integer Types.
                                                             (line  162)
* as_posix() (pathlib.PurePath method):  Methods and properties.
                                                             (line  172)
* as_string() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line   61)
* as_string() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line   60)
* as_tuple() (decimal.Decimal method):   Decimal objects.    (line  135)
* as_uri() (pathlib.Path method):        Parsing and generating URIs.
                                                             (line   42)
* as; except clause:                     except clause.      (line   30)
* as; import statement:                  The import statement.
                                                             (line   39)
* as; match statement:                   The match statement.
                                                             (line    6)
* as; with statement:                    The with statement. (line    6)
* ASCII:                                 Notation.           (line   32)
* ASCII <1>:                             Literals.           (line    8)
* ASCII (in module re):                  Flags.              (line   16)
* ascii_letters (in module string):      String constants.   (line    8)
* ascii_lowercase (in module string):    String constants.   (line   14)
* ascii_uppercase (in module string):    String constants.   (line   19)
* ascii() (in module curses.ascii):      curses ascii — Utilities for ASCII characters.
                                                             (line  211)
* asctime() (in module time):            Functions<5>.       (line    6)
* asdict() (in module dataclasses):      Module contents<5>. (line  345)
* asend() (agen method):                 Asynchronous generator-iterator methods.
                                                             (line   28)
* asin() (in module cmath):              Trigonometric functions<2>.
                                                             (line   12)
* asin() (in module math):               Trigonometric functions.
                                                             (line   11)
* asinh() (in module cmath):             Hyperbolic functions<2>.
                                                             (line   11)
* asinh() (in module math):              Hyperbolic functions.
                                                             (line   13)
* askcolor() (in module tkinter.colorchooser): tkinter colorchooser — Color choosing dialog.
                                                             (line   17)
* askdirectory() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   54)
* askfloat() (in module tkinter.simpledialog): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   14)
* askinteger() (in module tkinter.simpledialog): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   14)
* askokcancel() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  119)
* askopenfile() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   31)
* askopenfilename() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   42)
* askopenfilenames() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   42)
* askopenfiles() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   31)
* askquestion() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  113)
* askretrycancel() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  126)
* asksaveasfile() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   37)
* asksaveasfilename() (in module tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   49)
* askstring() (in module tkinter.simpledialog): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   14)
* askyesno() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  133)
* askyesnocancel() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  139)
* Assert (class in ast):                 Statements.         (line  126)
* assert_any_await() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  840)
* assert_any_call() (unittest.mock.Mock method): The Mock Class.
                                                             (line  149)
* assert_awaited_once_with() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  823)
* assert_awaited_once() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  790)
* assert_awaited_with() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  806)
* assert_awaited() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  770)
* assert_called_once_with() (unittest.mock.Mock method): The Mock Class.
                                                             (line  134)
* assert_called_once() (unittest.mock.Mock method): The Mock Class.
                                                             (line  106)
* assert_called_with() (unittest.mock.Mock method): The Mock Class.
                                                             (line  124)
* assert_called() (unittest.mock.Mock method): The Mock Class.
                                                             (line   95)
* assert_has_awaits() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  857)
* assert_has_calls() (unittest.mock.Mock method): The Mock Class.
                                                             (line  164)
* assert_never() (in module typing):     Functions and decorators.
                                                             (line   44)
* assert_not_awaited() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  884)
* assert_not_called() (unittest.mock.Mock method): The Mock Class.
                                                             (line  185)
* assert_python_failure() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   57)
* assert_python_ok() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   40)
* assert_type() (in module typing):      Functions and decorators.
                                                             (line   15)
* assertAlmostEqual() (unittest.TestCase method): Test cases.
                                                             (line  507)
* assertCountEqual() (unittest.TestCase method): Test cases. (line  562)
* assertDictEqual() (unittest.TestCase method): Test cases.  (line  671)
* assertEqual() (unittest.TestCase method): Test cases.      (line  174)
* assertFalse() (unittest.TestCase method): Test cases.      (line  199)
* assertGreater() (unittest.TestCase method): Test cases.    (line  531)
* assertGreaterEqual() (unittest.TestCase method): Test cases.
                                                             (line  531)
* assertIn() (unittest.TestCase method): Test cases.         (line  226)
* assertInBytecode() (test.support.bytecode_helper.BytecodeTestCase method): test support bytecode_helper — Support tools for testing correct bytecode generation.
                                                             (line   22)
* AssertionError:                        Concrete exceptions.
                                                             (line    8)
* assertIs() (unittest.TestCase method): Test cases.         (line  211)
* assertIsInstance() (unittest.TestCase method): Test cases. (line  233)
* assertIsNone() (unittest.TestCase method): Test cases.     (line  219)
* assertIsNot() (unittest.TestCase method): Test cases.      (line  211)
* assertIsNotNone() (unittest.TestCase method): Test cases.  (line  219)
* assertLess() (unittest.TestCase method): Test cases.       (line  531)
* assertLessEqual() (unittest.TestCase method): Test cases.  (line  531)
* assertListEqual() (unittest.TestCase method): Test cases.  (line  648)
* assertLogs() (unittest.TestCase method): Test cases.       (line  407)
* assertMultiLineEqual() (unittest.TestCase method): Test cases.
                                                             (line  623)
* assertNoLogs() (unittest.TestCase method): Test cases.     (line  451)
* assertNotAlmostEqual() (unittest.TestCase method): Test cases.
                                                             (line  507)
* assertNotEqual() (unittest.TestCase method): Test cases.   (line  194)
* assertNotIn() (unittest.TestCase method): Test cases.      (line  226)
* assertNotInBytecode() (test.support.bytecode_helper.BytecodeTestCase method): test support bytecode_helper — Support tools for testing correct bytecode generation.
                                                             (line   28)
* assertNotIsInstance() (unittest.TestCase method): Test cases.
                                                             (line  233)
* assertNotRegex() (unittest.TestCase method): Test cases.   (line  544)
* assertRaises() (unittest.TestCase method): Test cases.     (line  273)
* assertRaisesRegex() (unittest.TestCase method): Test cases.
                                                             (line  314)
* assertRegex() (unittest.TestCase method): Test cases.      (line  544)
* assertSequenceEqual() (unittest.TestCase method): Test cases.
                                                             (line  633)
* assertSetEqual() (unittest.TestCase method): Test cases.   (line  659)
* assertTrue() (unittest.TestCase method): Test cases.       (line  199)
* assertTupleEqual() (unittest.TestCase method): Test cases. (line  648)
* assertWarns() (unittest.TestCase method): Test cases.      (line  341)
* assertWarnsRegex() (unittest.TestCase method): Test cases. (line  382)
* Assign (class in ast):                 Statements.         (line    6)
* assignment expression:                 Boolean operations. (line   38)
* assignment; expression:                Boolean operations. (line   37)
* assignment; statement:                 Mutable sequences.  (line    6)
* assignment; statement <1>:             Assignment statements.
                                                             (line    6)
* AST (class in ast):                    Node classes.       (line    6)
* ast command line option; -a:           Command-Line Usage<4>.
                                                             (line   29)
* ast command line option; -h:           Command-Line Usage<4>.
                                                             (line   15)
* ast command line option; -help:        Command-Line Usage<4>.
                                                             (line   15)
* ast command line option; -i:           Command-Line Usage<4>.
                                                             (line   33)
* ast command line option; -include-attributes: Command-Line Usage<4>.
                                                             (line   29)
* ast command line option; -indent:      Command-Line Usage<4>.
                                                             (line   33)
* ast command line option; -m:           Command-Line Usage<4>.
                                                             (line   19)
* ast command line option; -mode:        Command-Line Usage<4>.
                                                             (line   19)
* ast command line option; -no-type-comments: Command-Line Usage<4>.
                                                             (line   25)
* astimezone() (datetime.datetime method): datetime Objects. (line  477)
* astuple() (in module dataclasses):     Module contents<5>. (line  377)
* async for; in comprehensions:          Displays for lists sets and dictionaries.
                                                             (line   14)
* AsyncContextDecorator (class in contextlib): Utilities.    (line  461)
* AsyncContextManager (class in typing): Aliases to contextlib ABCs.
                                                             (line   24)
* asynccontextmanager() (in module contextlib): Utilities.   (line   92)
* AsyncExitStack (class in contextlib):  Utilities.          (line  620)
* AsyncFor (class in ast):               Async and await.    (line   34)
* AsyncFunctionDef (class in ast):       Async and await.    (line    6)
* AsyncGenerator (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  185)
* AsyncGenerator (class in typing):      Aliases to asynchronous ABCs in collections abc.
                                                             (line   21)
* AsyncGeneratorType (in module types):  Standard Interpreter Types.
                                                             (line   49)
* asynchronous context manager:          Glossary.           (line   86)
* asynchronous generator:                Glossary.           (line   92)
* asynchronous generator iterator:       Glossary.           (line  109)
* asynchronous generator; asynchronous iterator: Asynchronous generator functions.
                                                             (line    6)
* asynchronous generator; function:      Asynchronous generator functions.
                                                             (line    6)
* asynchronous iterable:                 Glossary.           (line  126)
* asynchronous iterator:                 Glossary.           (line  132)
* asyncio.subprocess.DEVNULL (built-in variable): Constants<7>.
                                                             (line   23)
* asyncio.subprocess.PIPE (built-in variable): Constants<7>. (line    6)
* asyncio.subprocess.Process (built-in class): Interacting with Subprocesses.
                                                             (line   11)
* asyncio.subprocess.STDOUT (built-in variable): Constants<7>.
                                                             (line   17)
* AsyncIterable (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  171)
* AsyncIterable (class in typing):       Aliases to asynchronous ABCs in collections abc.
                                                             (line   39)
* AsyncIterator (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  178)
* AsyncIterator (class in typing):       Aliases to asynchronous ABCs in collections abc.
                                                             (line   49)
* AsyncMock (class in unittest.mock):    The Mock Class.     (line  699)
* AsyncResult (class in multiprocessing.pool): Process Pools.
                                                             (line  197)
* asyncSetUp() (unittest.IsolatedAsyncioTestCase method): Test cases.
                                                             (line  860)
* asyncTearDown() (unittest.IsolatedAsyncioTestCase method): Test cases.
                                                             (line  869)
* AsyncWith (class in ast):              Async and await.    (line   34)
* AT (in module token):                  token — Constants used with Python parse trees.
                                                             (line  302)
* at_eof() (asyncio.StreamReader method): StreamReader.      (line   85)
* atan() (in module cmath):              Trigonometric functions<2>.
                                                             (line   17)
* atan() (in module math):               Trigonometric functions.
                                                             (line   16)
* atan2() (in module math):              Trigonometric functions.
                                                             (line   21)
* atanh() (in module cmath):             Hyperbolic functions<2>.
                                                             (line   17)
* atanh() (in module math):              Hyperbolic functions.
                                                             (line   17)
* ATEQUAL (in module token):             token — Constants used with Python parse trees.
                                                             (line  305)
* atexit (weakref.finalize attribute):   weakref — Weak references.
                                                             (line  315)
* athrow() (agen method):                Asynchronous generator-iterator methods.
                                                             (line   43)
* atof() (in module locale):             locale — Internationalization services.
                                                             (line  513)
* atoi() (in module locale):             locale — Internationalization services.
                                                             (line  519)
* atom:                                  Atoms.              (line    6)
* atomic operation:                      Glossary.           (line  141)
* attach_loop() (asyncio.AbstractChildWatcher method): Process Watchers.
                                                             (line   63)
* attach_mock() (unittest.mock.Mock method): The Mock Class. (line  256)
* attach() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  167)
* attempted (doctest.TestResults attribute): TestResults objects.
                                                             (line   12)
* AttlistDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  295)
* attrgetter() (in module operator):     operator — Standard operators as functions.
                                                             (line  234)
* attrib (xml.etree.ElementTree.Element attribute): Element Objects.
                                                             (line   45)
* attribute:                             The standard type hierarchy.
                                                             (line   13)
* attribute <1>:                         Glossary.           (line  151)
* Attribute (class in ast):              Expressions<2>.     (line  170)
* attribute; assignment:                 Assignment statements.
                                                             (line    6)
* attribute; assignment <1>:             Assignment statements.
                                                             (line   76)
* attribute; deletion:                   The del statement<2>.
                                                             (line   20)
* attribute; reference:                  Attribute references.
                                                             (line    6)
* AttributeError:                        Concrete exceptions.
                                                             (line   12)
* attributes (xml.dom.Node attribute):   Node Objects.       (line   26)
* AttributesImpl (class in xml.sax.xmlreader): xml sax xmlreader — Interface for XML parsers.
                                                             (line   68)
* AttributesNSImpl (class in xml.sax.xmlreader): xml sax xmlreader — Interface for XML parsers.
                                                             (line   79)
* attroff() (curses.window method):      Window Objects.     (line   55)
* attron() (curses.window method):       Window Objects.     (line   60)
* attrset() (curses.window method):      Window Objects.     (line   65)
* audit events:                          Debugging and Profiling.
                                                             (line   13)
* audit() (in module sys):               sys — System-specific parameters and functions.
                                                             (line   91)
* auditing:                              sys — System-specific parameters and functions.
                                                             (line   93)
* AugAssign (class in ast):              Statements.         (line   94)
* augmented; assignment:                 Augmented assignment statements.
                                                             (line    6)
* AUGUST (in module calendar):           calendar — General calendar-related functions.
                                                             (line  488)
* auth() (ftplib.FTP_TLS method):        FTP_TLS objects.    (line   88)
* auth() (smtplib.SMTP method):          SMTP Objects.       (line  140)
* authenticate() (imaplib.IMAP4 method): IMAP4 Objects.      (line   37)
* AuthenticationError:                   Process and exceptions.
                                                             (line  272)
* authenticators() (netrc.netrc method): netrc Objects.      (line    8)
* authkey (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  174)
* auto (class in enum):                  Utilities and decorators.
                                                             (line    6)
* autocommit (sqlite3.Connection attribute): Connection objects.
                                                             (line  731)
* autorange() (timeit.Timer method):     Python Interface.   (line   91)
* available_timezones() (in module zoneinfo): Functions<3>.  (line    6)
* avoids_symlink_attacks (shutil.rmtree attribute): Directory and files operations.
                                                             (line  329)
* Await (class in ast):                  Async and await.    (line   14)
* await_args (unittest.mock.AsyncMock attribute): The Mock Class.
                                                             (line  913)
* await_args_list (unittest.mock.AsyncMock attribute): The Mock Class.
                                                             (line  931)
* await_count (unittest.mock.AsyncMock attribute): The Mock Class.
                                                             (line  897)
* await; in comprehensions:              Displays for lists sets and dictionaries.
                                                             (line   45)
* awaitable:                             Glossary.           (line  163)
* Awaitable (class in collections.abc):  Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  131)
* Awaitable (class in typing):           Aliases to asynchronous ABCs in collections abc.
                                                             (line   59)
* b'; bytes literal:                     String and Bytes literals.
                                                             (line   46)
* b"; bytes literal:                     String and Bytes literals.
                                                             (line   46)
* b16decode() (in module base64):        RFC 4648 Encodings. (line  123)
* b16encode() (in module base64):        RFC 4648 Encodings. (line  118)
* b2a_base64() (in module binascii):     binascii — Convert between binary and ASCII.
                                                             (line   61)
* b2a_hex() (in module binascii):        binascii — Convert between binary and ASCII.
                                                             (line  114)
* b2a_qp() (in module binascii):         binascii — Convert between binary and ASCII.
                                                             (line   77)
* b2a_uu() (in module binascii):         binascii — Convert between binary and ASCII.
                                                             (line   31)
* b32decode() (in module base64):        RFC 4648 Encodings. (line   78)
* b32encode() (in module base64):        RFC 4648 Encodings. (line   73)
* b32hexdecode() (in module base64):     RFC 4648 Encodings. (line  106)
* b32hexencode() (in module base64):     RFC 4648 Encodings. (line   99)
* b64decode() (in module base64):        RFC 4648 Encodings. (line   25)
* b64encode() (in module base64):        RFC 4648 Encodings. (line   10)
* b85decode() (in module base64):        Base85 Encodings.   (line   84)
* b85encode() (in module base64):        Base85 Encodings.   (line   73)
* Babyl (class in mailbox):              Babyl objects.      (line    6)
* BabylMessage (class in mailbox):       BabylMessage objects.
                                                             (line    6)
* back() (in module turtle):             Turtle motion.      (line   24)
* backend (in module readline):          readline — GNU readline interface.
                                                             (line   51)
* backslash character:                   Explicit line joining.
                                                             (line    6)
* backslashreplace_errors() (in module codecs): Error Handlers.
                                                             (line  161)
* backslashreplace; error handler's name: Error Handlers.    (line   15)
* backup() (sqlite3.Connection method):  Connection objects. (line  529)
* backward() (in module turtle):         Turtle motion.      (line   24)
* BadGzipFile:                           gzip — Support for gzip files.
                                                             (line   62)
* BadOptionError:                        Exceptions<10>.     (line   21)
* BadStatusLine:                         http client — HTTP protocol client.
                                                             (line  177)
* BadZipFile:                            zipfile — Work with ZIP archives.
                                                             (line   23)
* BadZipfile:                            zipfile — Work with ZIP archives.
                                                             (line   29)
* Barrier (class in asyncio):            Barrier.            (line    6)
* Barrier (class in multiprocessing):    Synchronization primitives.
                                                             (line   13)
* Barrier (class in threading):          Barrier objects.    (line   35)
* Barrier() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  160)
* base_exec_prefix (in module sys):      sys — System-specific parameters and functions.
                                                             (line  122)
* base_prefix (in module sys):           sys — System-specific parameters and functions.
                                                             (line  136)
* base64; encoding:                      base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line    8)
* BaseCGIHandler (class in wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line   53)
* BaseCookie (class in http.cookies):    http cookies — HTTP state management.
                                                             (line   38)
* BaseException:                         Base classes.       (line    9)
* BaseExceptionGroup:                    Exception groups.   (line   14)
* BaseHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  278)
* BaseHandler (class in wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line   88)
* BaseHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line   37)
* BaseHTTPRequestHandler (class in http.server): http server — HTTP servers.
                                                             (line   51)
* BaseManager (class in multiprocessing.managers): Managers. (line   23)
* basename() (in module os.path):        os path — Common pathname manipulations.
                                                             (line   62)
* BaseProtocol (class in asyncio):       Base Protocols.     (line    6)
* BaseProxy (class in multiprocessing.managers): Proxy Objects.
                                                             (line   92)
* BaseRequestHandler (class in socketserver): Request Handler Objects.
                                                             (line    6)
* BaseRotatingHandler (class in logging.handlers): BaseRotatingHandler.
                                                             (line   12)
* BaseSelector (class in selectors):     Classes<4>.         (line   53)
* BaseServer (class in socketserver):    Server Objects.     (line    6)
* BaseTransport (class in asyncio):      Transports Hierarchy.
                                                             (line    6)
* basicConfig() (in module logging):     Module-Level Functions.
                                                             (line  204)
* BasicContext (in module decimal):      Context objects.    (line   65)
* BasicInterpolation (class in configparser): Interpolation of values.
                                                             (line   10)
* batched() (in module itertools):       Itertool Functions. (line   71)
* baudrate() (in module curses):         Functions<6>.       (line   18)
* bbox() (tkinter.ttk.Treeview method):  ttk Treeview.       (line    8)
* BDADDR_ANY (in module socket):         Constants<8>.       (line  298)
* BDADDR_LOCAL (in module socket):       Constants<8>.       (line  298)
* Bdb (class in bdb):                    bdb — Debugger framework.
                                                             (line  124)
* BdbQuit:                               bdb — Debugger framework.
                                                             (line   15)
* BDFL:                                  Glossary.           (line  169)
* beep() (in module curses):             Functions<6>.       (line   26)
* Beep() (in module winsound):           winsound — Sound-playing interface for Windows.
                                                             (line   14)
* BEFORE_ASYNC_WITH (opcode):            Python Bytecode Instructions.
                                                             (line  361)
* BEFORE_WITH (opcode):                  Python Bytecode Instructions.
                                                             (line  513)
* begin_fill() (in module turtle):       Filling.            (line   16)
* begin_poly() (in module turtle):       Special Turtle methods.
                                                             (line    6)
* BEL (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   39)
* BELOW_NORMAL_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line   75)
* below() (curses.panel.Panel method):   Panel Objects.      (line   17)
* benchmarking:                          Functions<5>.       (line  216)
* benchmarking <1>:                      Functions<5>.       (line  247)
* benchmarking <2>:                      Functions<5>.       (line  615)
* Benchmarking:                          timeit — Measure execution time of small code snippets.
                                                             (line    8)
* betavariate() (in module random):      Real-valued distributions.
                                                             (line   33)
* bgcolor() (in module turtle):          Window control.     (line    6)
* bgpic() (in module turtle):            Window control.     (line   48)
* bidirectional() (in module unicodedata): unicodedata — Unicode Database.
                                                             (line   90)
* bigaddrspacetest() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  570)
* BigEndianStructure (class in ctypes):  Structured data types.
                                                             (line   22)
* BigEndianUnion (class in ctypes):      Structured data types.
                                                             (line   10)
* bigmemtest() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  554)
* bin() (in module enum):                Utilities and decorators.
                                                             (line  109)
* Binary (class in xmlrpc.client):       Binary Objects.     (line    6)
* binary file:                           Glossary.           (line  174)
* binary literal:                        Numeric literals.   (line    6)
* binary mode:                           Built-in Functions. (line 1464)
* binary semaphores:                     _thread — Low-level threading API.
                                                             (line    6)
* BINARY_OP (opcode):                    Python Bytecode Instructions.
                                                             (line  242)
* BINARY_SLICE (opcode):                 Python Bytecode Instructions.
                                                             (line  278)
* BINARY_SUBSCR (opcode):                Python Bytecode Instructions.
                                                             (line  253)
* binary; arithmetic; operation:         Binary arithmetic operations.
                                                             (line    6)
* binary; bitwise; operation:            Binary bitwise operations.
                                                             (line    6)
* binary; literals:                      Numeric Types — int float complex.
                                                             (line   19)
* binaryfunc (C type):                   Slot Type typedefs. (line  112)
* BinaryIO (class in typing):            ABCs for working with IO.
                                                             (line    6)
* bind (widgets):                        Bindings and Events.
                                                             (line    6)
* bind_partial() (inspect.Signature method): Introspecting callables with the Signature object.
                                                             (line  128)
* bind_port() (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   37)
* bind_textdomain_codeset() (in module locale): Access to message catalogs.
                                                             (line   16)
* bind_unix_socket() (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   54)
* bind() (inspect.Signature method):     Introspecting callables with the Signature object.
                                                             (line  121)
* bind() (socket.socket method):         Socket Objects.     (line   30)
* binding; name:                         Binding of names.   (line    6)
* binding; name <1>:                     Assignment statements.
                                                             (line    6)
* bindtextdomain() (in module gettext):  GNU gettext API.    (line   14)
* bindtextdomain() (in module locale):   Access to message catalogs.
                                                             (line   14)
* binomialvariate() (in module random):  Discrete distributions.
                                                             (line    8)
* BinOp (class in ast):                  Expressions<2>.     (line   41)
* bisect_left() (in module bisect):      bisect — Array bisection algorithm.
                                                             (line   32)
* bisect_right() (in module bisect):     bisect — Array bisection algorithm.
                                                             (line   57)
* bisect() (in module bisect):           bisect — Array bisection algorithm.
                                                             (line   57)
* bit_count() (int method):              Additional Methods on Integer Types.
                                                             (line   35)
* bit_length() (int method):             Additional Methods on Integer Types.
                                                             (line    9)
* BitAnd (class in ast):                 Expressions<2>.     (line   53)
* BitOr (class in ast):                  Expressions<2>.     (line   53)
* bits_per_digit (sys.int_info attribute): sys — System-specific parameters and functions.
                                                             (line 1147)
* bitwise; and:                          Binary bitwise operations.
                                                             (line   12)
* bitwise; operations:                   Bitwise Operations on Integer Types.
                                                             (line    6)
* bitwise; or:                           Binary bitwise operations.
                                                             (line   20)
* bitwise; xor:                          Binary bitwise operations.
                                                             (line   16)
* BitXor (class in ast):                 Expressions<2>.     (line   53)
* bk() (in module turtle):               Turtle motion.      (line   24)
* bkgd() (curses.window method):         Window Objects.     (line   70)
* bkgdset() (curses.window method):      Window Objects.     (line   82)
* blake2b, blake2s:                      BLAKE2.             (line    6)
* blake2b.MAX_DIGEST_SIZE (in module hashlib): Constants<5>. (line   24)
* blake2b.MAX_KEY_SIZE (in module hashlib): Constants<5>.    (line   18)
* blake2b.PERSON_SIZE (in module hashlib): Constants<5>.     (line   12)
* blake2b.SALT_SIZE (in module hashlib): Constants<5>.       (line    6)
* blake2b() (in module hashlib):         Creating hash objects.
                                                             (line    8)
* blake2s.MAX_DIGEST_SIZE (in module hashlib): Constants<5>. (line   26)
* blake2s.MAX_KEY_SIZE (in module hashlib): Constants<5>.    (line   20)
* blake2s.PERSON_SIZE (in module hashlib): Constants<5>.     (line   14)
* blake2s.SALT_SIZE (in module hashlib): Constants<5>.       (line    8)
* blake2s() (in module hashlib):         Creating hash objects.
                                                             (line   13)
* blank line:                            Blank lines.        (line    6)
* BLKTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  294)
* Blob (class in sqlite3):               Blob objects.       (line    6)
* blobopen() (sqlite3.Connection method): Connection objects.
                                                             (line   34)
* block:                                 Structure of a program.
                                                             (line    6)
* block_on_close (socketserver.ThreadingMixIn attribute): Server Creation Notes.
                                                             (line   44)
* block_size (hmac.HMAC attribute):      hmac — Keyed-Hashing for Message Authentication.
                                                             (line   98)
* blocked_domains() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   52)
* BlockingIOError:                       OS exceptions.      (line    9)
* BlockingIOError <1>:                   High-level Module Interface.
                                                             (line   67)
* blocksize (http.client.HTTPConnection attribute): HTTPConnection Objects.
                                                             (line  161)
* BNF:                                   Notation.           (line    6)
* BNF <1>:                               Expressions.        (line    6)
* body_encode() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  135)
* body_encoding (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   67)
* body_line_iterator() (in module email.iterators): email iterators Iterators.
                                                             (line   14)
* body() (tkinter.simpledialog.Dialog method): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   25)
* BOLD (in module tkinter.font):         tkinter font — Tkinter font wrapper.
                                                             (line   15)
* BOM (in module codecs):                codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_BE (in module codecs):             codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_LE (in module codecs):             codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF16 (in module codecs):          codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF16_BE (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF16_LE (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF32 (in module codecs):          codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF32_BE (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF32_LE (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  271)
* BOM_UTF8 (in module codecs):           codecs — Codec registry and base classes.
                                                             (line  271)
* bool (built-in class):                 Built-in Functions. (line  134)
* BOOLEAN_STATES (configparser.ConfigParser attribute): Customizing Parser Behaviour.
                                                             (line  245)
* Boolean; operation:                    Boolean operations. (line    6)
* Boolean; operations:                   Truth Value Testing.
                                                             (line    6)
* Boolean; operations <1>:               Boolean Operations — and or not.
                                                             (line    6)
* Boolean; type:                         Built-in Functions. (line  145)
* Boolean; values:                       Boolean Type - bool.
                                                             (line    9)
* BooleanOptionalAction (class in argparse): Action classes. (line   64)
* BoolOp (class in ast):                 Expressions<2>.     (line   69)
* bootstrap() (in module ensurepip):     Module API.         (line   13)
* border() (curses.window method):       Window Objects.     (line   93)
* borrowed reference:                    Glossary.           (line  185)
* bottom_panel() (in module curses.panel): Functions<7>.     (line    8)
* bottom() (curses.panel.Panel method):  Panel Objects.      (line   21)
* BoundArguments (class in inspect):     Introspecting callables with the Signature object.
                                                             (line  326)
* BoundaryError:                         email errors Exception and Defect classes.
                                                             (line   38)
* BoundedSemaphore (class in asyncio):   BoundedSemaphore.   (line    6)
* BoundedSemaphore (class in multiprocessing): Synchronization primitives.
                                                             (line   22)
* BoundedSemaphore (class in threading): Semaphore objects.  (line   72)
* BoundedSemaphore() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  167)
* box() (curses.window method):          Window Objects.     (line  132)
* bpbynumber (bdb.Breakpoint attribute): bdb — Debugger framework.
                                                             (line  107)
* bpformat() (bdb.Breakpoint method):    bdb — Debugger framework.
                                                             (line   56)
* bplist (bdb.Breakpoint attribute):     bdb — Debugger framework.
                                                             (line  111)
* bpprint() (bdb.Breakpoint method):     bdb — Debugger framework.
                                                             (line   75)
* BRANCH (monitoring event):             Events.             (line    8)
* Break (class in ast):                  Control flow.       (line   99)
* break (pdb command):                   Debugger commands.  (line   97)
* break_anywhere() (bdb.Bdb method):     bdb — Debugger framework.
                                                             (line  257)
* break_here() (bdb.Bdb method):         bdb — Debugger framework.
                                                             (line  248)
* break_long_words (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  247)
* break_on_hyphens (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  256)
* Breakpoint (class in bdb):             bdb — Debugger framework.
                                                             (line   22)
* breakpointhook() (in module sys):      sys — System-specific parameters and functions.
                                                             (line  241)
* breakpoints:                           Help menu Shell and Editor.
                                                             (line   29)
* broadcast_address (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   91)
* broadcast_address (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  311)
* broken (asyncio.Barrier attribute):    Barrier.            (line  102)
* broken (threading.Barrier attribute):  Barrier objects.    (line  100)
* BrokenBarrierError:                    Barrier objects.    (line  105)
* BrokenBarrierError <1>:                Barrier.            (line  107)
* BrokenExecutor:                        Exception classes.  (line   18)
* BrokenPipeError:                       OS exceptions.      (line   38)
* BrokenProcessPool:                     Exception classes.  (line   41)
* BrokenThreadPool:                      Exception classes.  (line   33)
* BROWSER:                               webbrowser — Convenient web-browser controller.
                                                             (line   20)
* BROWSER <1>:                           webbrowser — Convenient web-browser controller.
                                                             (line   34)
* BROWSER <2>:                           Command-line interface<4>.
                                                             (line   86)
* BS (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   42)
* BsdDbShelf (class in shelve):          Restrictions.       (line   60)
* buf (multiprocessing.shared_memory.SharedMemory attribute): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  116)
* Buffer (class in collections.abc):     Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  195)
* buffer (io.TextIOBase attribute):      Text I/O<2>.        (line   30)
* buffer (unittest.TestResult attribute): Loading and running tests.
                                                             (line  290)
* buffer interface; (see buffer protocol): Iterator Protocol.
                                                             (line   78)
* buffer object; (see buffer protocol):  Iterator Protocol.  (line   77)
* buffer protocol:                       Iterator Protocol.  (line   78)
* buffer protocol; binary sequence types: printf-style String Formatting.
                                                             (line  196)
* buffer protocol; str (built-in class): Text Sequence Type — str.
                                                             (line   65)
* buffer size, I/O:                      Built-in Functions. (line 1464)
* buffer_info() (array.array method):    array — Efficient arrays of numeric values.
                                                             (line  127)
* buffer_size (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  169)
* buffer_text (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  176)
* buffer_updated() (asyncio.BufferedProtocol method): Buffered Streaming Protocols.
                                                             (line   33)
* buffer_used (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  187)
* BufferedIOBase (class in io):          I/O Base Classes.   (line  223)
* BufferedProtocol (class in asyncio):   Base Protocols.     (line   15)
* BufferedRandom (class in io):          Buffered Streams.   (line  132)
* BufferedReader (class in io):          Buffered Streams.   (line   55)
* BufferedRWPair (class in io):          Buffered Streams.   (line  146)
* BufferedWriter (class in io):          Buffered Streams.   (line   92)
* BufferError:                           Base classes.       (line   78)
* BufferFlags (class in inspect):        Buffer flags.       (line    6)
* BufferingFormatter (class in logging): Formatter Objects.  (line  131)
* BufferingHandler (class in logging.handlers): MemoryHandler.
                                                             (line   19)
* BufferTooShort:                        Process and exceptions.
                                                             (line  264)
* BUILD_CONST_KEY_MAP (opcode):          Python Bytecode Instructions.
                                                             (line  693)
* BUILD_LIST (opcode):                   Python Bytecode Instructions.
                                                             (line  675)
* BUILD_MAP (opcode):                    Python Bytecode Instructions.
                                                             (line  683)
* build_opener() (in module urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  121)
* BUILD_SET (opcode):                    Python Bytecode Instructions.
                                                             (line  679)
* BUILD_SLICE (opcode):                  Python Bytecode Instructions.
                                                             (line 1142)
* BUILD_STRING (opcode):                 Python Bytecode Instructions.
                                                             (line  702)
* BUILD_TUPLE (opcode):                  Python Bytecode Instructions.
                                                             (line  662)
* built-in function; __import__:         Importing Modules<2>.
                                                             (line   31)
* built-in function; __import__():       Built-in Functions. (line 2170)
* built-in function; abs:                Emulating numeric types.
                                                             (line  113)
* built-in function; abs <1>:            Number Protocol.    (line  100)
* built-in function; abs():              Built-in Functions. (line   43)
* built-in function; aiter():            Built-in Functions. (line   50)
* built-in function; all():              Built-in Functions. (line   60)
* built-in function; anext():            Built-in Functions. (line   71)
* built-in function; any():              Built-in Functions. (line   90)
* built-in function; ascii:              Object Protocol.    (line  346)
* built-in function; ascii():            Built-in Functions. (line  101)
* built-in function; bin():              Built-in Functions. (line  109)
* built-in function; breakpoint():       Built-in Functions. (line  147)
* built-in function; bytes:              Basic customization.
                                                             (line  146)
* built-in function; bytes <1>:          Object Protocol.    (line  373)
* built-in function; call:               Calls.              (line  142)
* built-in function; callable():         Built-in Functions. (line  225)
* built-in function; chr:                Immutable sequences.
                                                             (line   15)
* built-in function; chr():              Built-in Functions. (line  237)
* built-in function; classmethod:        Implementing functions and methods.
                                                             (line  194)
* built-in function; classmethod():      Built-in Functions. (line  248)
* built-in function; compile:            The global statement.
                                                             (line   23)
* built-in function; compile <1>:        Code Objects.       (line    6)
* built-in function; compile <2>:        Standard Interpreter Types.
                                                             (line   58)
* built-in function; compile <3>:        Importing Modules<2>.
                                                             (line  131)
* built-in function; compile():          Built-in Functions. (line  286)
* built-in function; complex:            Emulating numeric types.
                                                             (line  120)
* built-in function; complex <1>:        Numeric Types — int float complex.
                                                             (line   27)
* built-in function; delattr():          Built-in Functions. (line  439)
* built-in function; dir():              Built-in Functions. (line  462)
* built-in function; divmod:             Emulating numeric types.
                                                             (line   26)
* built-in function; divmod <1>:         Emulating numeric types.
                                                             (line   56)
* built-in function; divmod <2>:         Number Protocol.    (line   71)
* built-in function; divmod():           Built-in Functions. (line  523)
* built-in function; enumerate():        Built-in Functions. (line  535)
* built-in function; eval:               The global statement.
                                                             (line   23)
* built-in function; eval <1>:           Expression input.   (line    6)
* built-in function; eval <2>:           Code Objects.       (line   17)
* built-in function; eval <3>:           Functions<4>.       (line   86)
* built-in function; eval <4>:           PrettyPrinter Objects.
                                                             (line   68)
* built-in function; eval():             Built-in Functions. (line  558)
* built-in function; exec:               The global statement.
                                                             (line   23)
* built-in function; exec <1>:           Built-in Functions. (line  633)
* built-in function; exec <2>:           Code Objects.       (line   17)
* built-in function; exec():             Built-in Functions. (line  633)
* built-in function; filter():           Built-in Functions. (line  703)
* built-in function; float:              Emulating numeric types.
                                                             (line  120)
* built-in function; float <1>:          Numeric Types — int float complex.
                                                             (line   27)
* built-in function; float <2>:          Number Protocol.    (line  265)
* built-in function; format():           Built-in Functions. (line  786)
* built-in function; getattr():          Built-in Functions. (line  819)
* built-in function; globals():          Built-in Functions. (line  836)
* built-in function; hasattr():          Built-in Functions. (line  842)
* built-in function; hash:               Basic customization.
                                                             (line  237)
* built-in function; hash <1>:           Immutable Sequence Types.
                                                             (line    6)
* built-in function; hash <2>:           Object Protocol.    (line  427)
* built-in function; hash <3>:           PyTypeObject Slots. (line  373)
* built-in function; hash():             Built-in Functions. (line  849)
* built-in function; help:               Operating system interface.
                                                             (line   20)
* built-in function; help():             Built-in Functions. (line  861)
* built-in function; hex():              Built-in Functions. (line  885)
* built-in function; id:                 Objects values and types.
                                                             (line   10)
* built-in function; id():               Built-in Functions. (line  916)
* built-in function; input():            Built-in Functions. (line  929)
* built-in function; int:                Emulating numeric types.
                                                             (line  120)
* built-in function; int <1>:            Numeric Types — int float complex.
                                                             (line   27)
* built-in function; int <2>:            Number Protocol.    (line  257)
* built-in function; isinstance():       Built-in Functions. (line 1026)
* built-in function; issubclass():       Built-in Functions. (line 1042)
* built-in function; iter():             Built-in Functions. (line 1055)
* built-in function; len:                Sequences.          (line    6)
* built-in function; len <1>:            Set types.          (line    6)
* built-in function; len <2>:            Mappings.           (line    6)
* built-in function; len <3>:            Emulating container types.
                                                             (line   46)
* built-in function; len <4>:            Common Sequence Operations.
                                                             (line   21)
* built-in function; len <5>:            Mapping Types — dict.
                                                             (line    6)
* built-in function; len <6>:            Object Protocol.    (line  476)
* built-in function; len <7>:            Sequence Protocol.  (line   16)
* built-in function; len <8>:            Mapping Protocol.   (line   19)
* built-in function; len <9>:            List Objects.       (line   41)
* built-in function; len <10>:           Dictionary Objects. (line  237)
* built-in function; len <11>:           Set Objects.        (line   99)
* built-in function; len():              Built-in Functions. (line 1085)
* built-in function; locals():           Built-in Functions. (line 1101)
* built-in function; map():              Built-in Functions. (line 1153)
* built-in function; max:                Common Sequence Operations.
                                                             (line   21)
* built-in function; max():              Built-in Functions. (line 1163)
* built-in function; min:                Common Sequence Operations.
                                                             (line   21)
* built-in function; min():              Built-in Functions. (line 1197)
* built-in function; multiprocessing.Manager(): Managers.    (line   12)
* built-in function; next():             Built-in Functions. (line 1226)
* built-in function; oct():              Built-in Functions. (line 1246)
* built-in function; open:               Reading and Writing Files.
                                                             (line    6)
* built-in function; open <1>:           I/O objects also known as file objects.
                                                             (line    6)
* built-in function; open():             Built-in Functions. (line 1271)
* built-in function; ord:                Immutable sequences.
                                                             (line   15)
* built-in function; ord():              Built-in Functions. (line 1509)
* built-in function; pow:                Emulating numeric types.
                                                             (line   26)
* built-in function; pow <1>:            Emulating numeric types.
                                                             (line   26)
* built-in function; pow <2>:            Emulating numeric types.
                                                             (line   56)
* built-in function; pow <3>:            Emulating numeric types.
                                                             (line   67)
* built-in function; pow <4>:            Number Protocol.    (line   80)
* built-in function; pow <5>:            Number Protocol.    (line  206)
* built-in function; pow():              Built-in Functions. (line 1522)
* built-in function; print:              Basic customization.
                                                             (line  151)
* built-in function; print():            Built-in Functions. (line 1562)
* built-in function; property.deleter(): Built-in Functions. (line 1637)
* built-in function; property.getter():  Built-in Functions. (line 1633)
* built-in function; property.setter():  Built-in Functions. (line 1635)
* built-in function; range:              The for statement.  (line   37)
* built-in function; repr:               Expression statements.
                                                             (line   17)
* built-in function; repr <1>:           Finalization and De-allocation.
                                                             (line   90)
* built-in function; repr <2>:           Object Protocol.    (line  331)
* built-in function; repr <3>:           PyTypeObject Slots. (line  308)
* built-in function; repr():             Built-in Functions. (line 1686)
* built-in function; reversed():         Built-in Functions. (line 1709)
* built-in function; round:              Emulating numeric types.
                                                             (line  143)
* built-in function; round():            Built-in Functions. (line 1717)
* built-in function; setattr():          Built-in Functions. (line 1752)
* built-in function; slice:              Slice objects.      (line    6)
* built-in function; slice <1>:          Python Bytecode Instructions.
                                                             (line 1144)
* built-in function; sorted():           Built-in Functions. (line 1801)
* built-in function; staticmethod:       Implementing functions and methods.
                                                             (line  202)
* built-in function; staticmethod():     Built-in Functions. (line 1837)
* built-in function; sum():              Built-in Functions. (line 1896)
* built-in function; tuple:              Sequence Protocol.  (line  120)
* built-in function; tuple <1>:          List Objects.       (line  162)
* built-in function; type:               Objects values and types.
                                                             (line   10)
* built-in function; type <1>:           Metaclasses.        (line    6)
* built-in function; type <2>:           Type Objects.       (line    6)
* built-in function; type <3>:           Object Protocol.    (line  458)
* built-in function; vars():             Built-in Functions. (line 2051)
* built-in function; zip():              Built-in Functions. (line 2075)
* built-in method; call:                 Calls.              (line  142)
* built-in; method:                      Built-in methods.   (line    6)
* built-in; types:                       Built-in Types.     (line    9)
* builtin_module_names (in module sys):  sys — System-specific parameters and functions.
                                                             (line  156)
* BuiltinFunctionType (in module types): Standard Interpreter Types.
                                                             (line   81)
* BuiltinImporter (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   67)
* BuiltinMethodType (in module types):   Standard Interpreter Types.
                                                             (line   81)
* busy_retry() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  196)
* BUTTON_ALT (in module curses):         Constants<6>.       (line  627)
* BUTTON_CTRL (in module curses):        Constants<6>.       (line  624)
* BUTTON_SHIFT (in module curses):       Constants<6>.       (line  621)
* buttonbox() (tkinter.simpledialog.Dialog method): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   30)
* BUTTONn_CLICKED (in module curses):    Constants<6>.       (line  612)
* BUTTONn_DOUBLE_CLICKED (in module curses): Constants<6>.   (line  615)
* BUTTONn_PRESSED (in module curses):    Constants<6>.       (line  606)
* BUTTONn_RELEASED (in module curses):   Constants<6>.       (line  609)
* BUTTONn_TRIPLE_CLICKED (in module curses): Constants<6>.   (line  618)
* bye() (in module turtle):              Methods specific to Screen not inherited from TurtleScreen.
                                                             (line    6)
* byref() (in module ctypes):            Utility functions.  (line   19)
* byte:                                  Immutable sequences.
                                                             (line   39)
* bytearray:                             Mutable sequences.  (line   25)
* bytearray (built-in class):            Bytearray Objects.  (line    9)
* bytearray; formatting:                 printf-style Bytes Formatting.
                                                             (line    6)
* bytearray; interpolation:              printf-style Bytes Formatting.
                                                             (line    6)
* bytearray; methods:                    Bytes and Bytearray Operations.
                                                             (line    6)
* bytecode:                              Code objects.       (line    6)
* bytecode <1>:                          Glossary.           (line  217)
* Bytecode (class in dis):               Bytecode analysis.  (line   12)
* BYTECODE_SUFFIXES (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   40)
* Bytecode.codeobj (in module dis):      Bytecode analysis.  (line   49)
* Bytecode.first_line (in module dis):   Bytecode analysis.  (line   53)
* BytecodeTestCase (class in test.support.bytecode_helper): test support bytecode_helper — Support tools for testing correct bytecode generation.
                                                             (line   13)
* byteorder (in module sys):             sys — System-specific parameters and functions.
                                                             (line  149)
* bytes:                                 Immutable sequences.
                                                             (line   39)
* bytes (built-in class):                Bytes Objects.      (line   12)
* bytes (uuid.UUID attribute):           uuid — UUID objects according to RFC 4122.
                                                             (line   86)
* bytes literal:                         Literals.           (line    8)
* bytes_le (uuid.UUID attribute):        uuid — UUID objects according to RFC 4122.
                                                             (line   91)
* bytes_warning (sys.flags attribute):   sys — System-specific parameters and functions.
                                                             (line  557)
* bytes-like object:                     Glossary.           (line  199)
* bytes; formatting:                     printf-style Bytes Formatting.
                                                             (line    6)
* bytes; interpolation:                  printf-style Bytes Formatting.
                                                             (line    6)
* bytes; methods:                        Bytes and Bytearray Operations.
                                                             (line    6)
* bytes; str (built-in class):           Text Sequence Type — str.
                                                             (line   65)
* BytesFeedParser (class in email.parser): FeedParser API.   (line   27)
* BytesGenerator (class in email.generator): email generator Generating MIME documents.
                                                             (line   42)
* BytesHeaderParser (class in email.parser): Parser API.     (line   67)
* BytesIO (class in io):                 Buffered Streams.   (line    9)
* BytesParser (class in email.parser):   Parser API.         (line   17)
* ByteString (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   67)
* ByteString (class in typing):          Aliases to container ABCs in collections abc.
                                                             (line   14)
* byteswap() (array.array method):       array — Efficient arrays of numeric values.
                                                             (line  147)
* BytesWarning:                          Warnings.           (line   80)
* BZ2Compressor (class in bz2):          Incremental de compression.
                                                             (line    6)
* BZ2Decompressor (class in bz2):        Incremental de compression.
                                                             (line   33)
* BZ2File (class in bz2):                De compression of files.
                                                             (line   40)
* C:                                     String and Bytes literals.
                                                             (line   74)
* c_bool (class in ctypes):              Fundamental data types<2>.
                                                             (line  207)
* c_byte (class in ctypes):              Fundamental data types<2>.
                                                             (line   45)
* c_char (class in ctypes):              Fundamental data types<2>.
                                                             (line   51)
* c_char_p (class in ctypes):            Fundamental data types<2>.
                                                             (line   58)
* C_CONTIGUOUS (inspect.BufferFlags attribute): Buffer flags.
                                                             (line   25)
* c_contiguous (memoryview attribute):   Memory Views.       (line  476)
* c_double (class in ctypes):            Fundamental data types<2>.
                                                             (line   65)
* c_float (class in ctypes):             Fundamental data types<2>.
                                                             (line   76)
* c_int (class in ctypes):               Fundamental data types<2>.
                                                             (line   81)
* c_int16 (class in ctypes):             Fundamental data types<2>.
                                                             (line   93)
* c_int32 (class in ctypes):             Fundamental data types<2>.
                                                             (line   98)
* c_int64 (class in ctypes):             Fundamental data types<2>.
                                                             (line  103)
* c_int8 (class in ctypes):              Fundamental data types<2>.
                                                             (line   88)
* c_long (class in ctypes):              Fundamental data types<2>.
                                                             (line  108)
* c_longdouble (class in ctypes):        Fundamental data types<2>.
                                                             (line   70)
* c_longlong (class in ctypes):          Fundamental data types<2>.
                                                             (line  113)
* C_RAISE (monitoring event):            Events.             (line   16)
* C_RETURN (monitoring event):           Events.             (line   21)
* c_short (class in ctypes):             Fundamental data types<2>.
                                                             (line  119)
* c_size_t (class in ctypes):            Fundamental data types<2>.
                                                             (line  124)
* c_ssize_t (class in ctypes):           Fundamental data types<2>.
                                                             (line  128)
* c_time_t (class in ctypes):            Fundamental data types<2>.
                                                             (line  134)
* c_ubyte (class in ctypes):             Fundamental data types<2>.
                                                             (line  140)
* c_uint (class in ctypes):              Fundamental data types<2>.
                                                             (line  146)
* c_uint16 (class in ctypes):            Fundamental data types<2>.
                                                             (line  158)
* c_uint32 (class in ctypes):            Fundamental data types<2>.
                                                             (line  163)
* c_uint64 (class in ctypes):            Fundamental data types<2>.
                                                             (line  168)
* c_uint8 (class in ctypes):             Fundamental data types<2>.
                                                             (line  153)
* c_ulong (class in ctypes):             Fundamental data types<2>.
                                                             (line  173)
* c_ulonglong (class in ctypes):         Fundamental data types<2>.
                                                             (line  178)
* c_ushort (class in ctypes):            Fundamental data types<2>.
                                                             (line  184)
* c_void_p (class in ctypes):            Fundamental data types<2>.
                                                             (line  189)
* c_wchar (class in ctypes):             Fundamental data types<2>.
                                                             (line  194)
* c_wchar_p (class in ctypes):           Fundamental data types<2>.
                                                             (line  201)
* C-contiguous:                          shape strides suboffsets.
                                                             (line   34)
* C-contiguous <1>:                      Glossary.           (line  358)
* C; language:                           The standard type hierarchy.
                                                             (line    6)
* C; language <1>:                       numbers Real float. (line    6)
* C; language <2>:                       Built-in functions. (line    6)
* C; language <3>:                       Comparisons.        (line    6)
* C; language <4>:                       Numeric Types — int float complex.
                                                             (line    6)
* C; structures:                         struct — Interpret bytes as packed binary data.
                                                             (line    8)
* C14NWriterTarget (class in xml.etree.ElementTree): TreeBuilder Objects.
                                                             (line   94)
* CACHE (opcode):                        Python Bytecode Instructions.
                                                             (line  177)
* cache_clear() (functools.lru_cache method): functools — Higher-order functions and operations on callable objects.
                                                             (line  201)
* cache_from_source() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line   21)
* cache_info() (functools.lru_cache method): functools — Higher-order functions and operations on callable objects.
                                                             (line  196)
* cache() (in module functools):         functools — Higher-order functions and operations on callable objects.
                                                             (line   16)
* cached (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  421)
* cached_property() (in module functools): functools — Higher-order functions and operations on callable objects.
                                                             (line   49)
* CacheFTPHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  436)
* calcobjsize() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  438)
* calcsize() (in module struct):         Functions and Exceptions.
                                                             (line   55)
* calcvobjsize() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  444)
* Calendar (class in calendar):          calendar — General calendar-related functions.
                                                             (line   27)
* calendar command line option; -c:      Command-Line Usage. (line  117)
* calendar command line option; -css:    Command-Line Usage. (line  117)
* calendar command line option; -e:      Command-Line Usage. (line   66)
* calendar command line option; -encoding: Command-Line Usage.
                                                             (line   66)
* calendar command line option; -f:      Command-Line Usage. (line   75)
* calendar command line option; -first-weekday: Command-Line Usage.
                                                             (line   75)
* calendar command line option; -h:      Command-Line Usage. (line   57)
* calendar command line option; -help:   Command-Line Usage. (line   57)
* calendar command line option; -L:      Command-Line Usage. (line   61)
* calendar command line option; -l:      Command-Line Usage. (line  100)
* calendar command line option; -lines:  Command-Line Usage. (line  100)
* calendar command line option; -locale: Command-Line Usage. (line   61)
* calendar command line option; -m:      Command-Line Usage. (line  111)
* calendar command line option; -months: Command-Line Usage. (line  111)
* calendar command line option; -s:      Command-Line Usage. (line  106)
* calendar command line option; -spacing: Command-Line Usage.
                                                             (line  106)
* calendar command line option; -t:      Command-Line Usage. (line   71)
* calendar command line option; -type:   Command-Line Usage. (line   71)
* calendar command line option; -w:      Command-Line Usage. (line   94)
* calendar command line option; -width:  Command-Line Usage. (line   94)
* calendar command line option; month:   Command-Line Usage. (line   86)
* calendar command line option; year:    Command-Line Usage. (line   82)
* calendar() (in module calendar):       calendar — General calendar-related functions.
                                                             (line  411)
* call:                                  Slicings.           (line   39)
* Call (class in ast):                   Expressions<2>.     (line  121)
* CALL (monitoring event):               Events.             (line   12)
* CALL (opcode):                         Python Bytecode Instructions.
                                                             (line 1036)
* call_args (unittest.mock.Mock attribute): The Mock Class.  (line  436)
* call_args_list (unittest.mock.Mock attribute): The Mock Class.
                                                             (line  480)
* call_at() (asyncio.loop method):       Scheduling delayed callbacks.
                                                             (line   41)
* call_count (unittest.mock.Mock attribute): The Mock Class. (line  329)
* call_exception_handler() (asyncio.loop method): Error handling API.
                                                             (line   45)
* CALL_FUNCTION_EX (opcode):             Python Bytecode Instructions.
                                                             (line 1088)
* CALL_INTRINSIC_1 (opcode):             Python Bytecode Instructions.
                                                             (line 1292)
* CALL_INTRINSIC_2 (opcode):             Python Bytecode Instructions.
                                                             (line 1353)
* CALL_KW (opcode):                      Python Bytecode Instructions.
                                                             (line 1061)
* call_later() (asyncio.loop method):    Scheduling delayed callbacks.
                                                             (line   10)
* call_list() (unittest.mock.call method): call.             (line   19)
* call_soon_threadsafe() (asyncio.loop method): Scheduling callbacks.
                                                             (line   24)
* call_soon() (asyncio.loop method):     Scheduling callbacks.
                                                             (line    6)
* call_tracing() (in module sys):        sys — System-specific parameters and functions.
                                                             (line  165)
* call; instance:                        Emulating callable objects.
                                                             (line    8)
* call() (in module operator):           operator — Standard operators as functions.
                                                             (line  221)
* call() (in module subprocess):         Older high-level API.
                                                             (line   10)
* call() (in module unittest.mock):      call.               (line    6)
* callable:                              Glossary.           (line  232)
* Callable (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   19)
* Callable (in module typing):           Aliases to other ABCs in collections abc.
                                                             (line   22)
* CallableProxyType (in module weakref): weakref — Weak references.
                                                             (line  338)
* callback:                              Glossary.           (line  243)
* callback (optparse.Option attribute):  Option attributes.  (line   68)
* callback_args (optparse.Option attribute): Option attributes.
                                                             (line   74)
* callback_kwargs (optparse.Option attribute): Option attributes.
                                                             (line   74)
* callback() (contextlib.ExitStack method): Utilities.       (line  581)
* callbacks (in module gc):              gc — Garbage Collector interface.
                                                             (line  257)
* called (unittest.mock.Mock attribute): The Mock Class.     (line  317)
* CalledProcessError:                    Using the subprocess Module.
                                                             (line  205)
* calloc (C function):                   Overview<4>.        (line   33)
* CAN (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   96)
* CAN_BCM (in module socket):            Constants<8>.       (line  145)
* can_change_color() (in module curses): Functions<6>.       (line   30)
* can_fetch() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   33)
* CAN_ISOTP (in module socket):          Constants<8>.       (line  184)
* CAN_J1939 (in module socket):          Constants<8>.       (line  193)
* CAN_RAW_FD_FRAMES (in module socket):  Constants<8>.       (line  160)
* CAN_RAW_JOIN_FILTERS (in module socket): Constants<8>.     (line  173)
* can_symlink() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   74)
* can_write_eof() (asyncio.StreamWriter method): StreamWriter.
                                                             (line   50)
* can_write_eof() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   14)
* can_xattr() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   78)
* CANCEL (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  155)
* cancel_command() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line   82)
* cancel_dump_traceback_later() (in module faulthandler): Dumping the tracebacks after a timeout.
                                                             (line   29)
* cancel_join_thread() (multiprocessing.Queue method): Pipes and Queues.
                                                             (line  200)
* cancel() (asyncio.Future method):      Future Object.      (line  113)
* cancel() (asyncio.Handle method):      Callback handles.   (line   18)
* cancel() (asyncio.Task method):        Task object.        (line  199)
* cancel() (concurrent.futures.Future method): Future Objects.
                                                             (line   16)
* cancel() (sched.scheduler method):     Scheduler Objects.  (line   41)
* cancel() (threading.Timer method):     Timer objects.      (line   35)
* cancel() (tkinter.dnd.DndHandler method): tkinter dnd — Drag and drop support.
                                                             (line   48)
* cancelled() (asyncio.Future method):   Future Object.      (line   71)
* cancelled() (asyncio.Handle method):   Callback handles.   (line   23)
* cancelled() (asyncio.Task method):     Task object.        (line  262)
* cancelled() (concurrent.futures.Future method): Future Objects.
                                                             (line   23)
* CancelledError:                        Exception classes.  (line    6)
* CancelledError <1>:                    Exceptions<13>.     (line   18)
* cancelling() (asyncio.Task method):    Task object.        (line  319)
* CannotSendHeader:                      http client — HTTP protocol client.
                                                             (line  169)
* CannotSendRequest:                     http client — HTTP protocol client.
                                                             (line  165)
* canonic() (bdb.Bdb method):            bdb — Debugger framework.
                                                             (line  143)
* canonical() (decimal.Context method):  Context objects.    (line  269)
* canonical() (decimal.Decimal method):  Decimal objects.    (line  140)
* canonicalize() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line    6)
* capa() (poplib.POP3 method):           POP3 Objects.       (line   24)
* capitalize() (bytearray method):       Bytes and Bytearray Operations.
                                                             (line  469)
* capitalize() (bytes method):           Bytes and Bytearray Operations.
                                                             (line  469)
* capitalize() (str method):             String Methods<2>.  (line   22)
* capitals (decimal.Context attribute):  Context objects.    (line  146)
* CapsuleType (class in types):          Standard Interpreter Types.
                                                             (line  293)
* captured_stderr() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  332)
* captured_stdin() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  332)
* captured_stdout() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  332)
* captureWarnings() (in module logging): Integration with the warnings module.
                                                             (line    9)
* capwords() (in module string):         Helper functions.   (line    6)
* case block:                            Irrefutable Case Blocks.
                                                             (line    6)
* casefold() (str method):               String Methods<2>.  (line   32)
* cast() (in module ctypes):             Utility functions.  (line   33)
* cast() (in module typing):             Functions and decorators.
                                                             (line    6)
* cast() (memoryview method):            Memory Views.       (line  274)
* catch_threading_exception() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   47)
* catch_unraisable_exception() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  600)
* catch_warnings (class in warnings):    Available Context Managers.
                                                             (line    6)
* category() (in module unicodedata):    unicodedata — Unicode Database.
                                                             (line   80)
* cbreak() (in module curses):           Functions<6>.       (line   35)
* cbrt() (in module math):               Power exponential and logarithmic functions.
                                                             (line    6)
* CC:                                    New Improved and Deprecated Modules<4>.
                                                             (line   58)
* ccc() (ftplib.FTP_TLS method):         FTP_TLS objects.    (line   98)
* cdf() (statistics.NormalDist method):  NormalDist objects. (line   86)
* CDLL (class in ctypes):                Loading shared libraries.
                                                             (line    9)
* ceil() (in module math):               Numeric Types — int float complex.
                                                             (line  106)
* ceil() (in module math) <1>:           Floating point arithmetic.
                                                             (line    6)
* CellType (in module types):            Standard Interpreter Types.
                                                             (line   70)
* center() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line  291)
* center() (bytes method):               Bytes and Bytearray Operations.
                                                             (line  291)
* center() (str method):                 String Methods<2>.  (line   53)
* CERT_NONE (in module ssl):             Constants<9>.       (line   11)
* CERT_OPTIONAL (in module ssl):         Constants<9>.       (line   24)
* CERT_REQUIRED (in module ssl):         Constants<9>.       (line   40)
* cert_store_stats() (ssl.SSLContext method): SSL contexts.  (line   88)
* cert_time_to_seconds() (in module ssl): Certificate handling.
                                                             (line    6)
* CertificateError:                      Exceptions<16>.     (line   94)
* certificates:                          SSL contexts.       (line  760)
* CFLAGS:                                New Improved and Deprecated Modules<4>.
                                                             (line   59)
* CFLAGS <1>:                            Performance options.
                                                             (line   28)
* CFLAGS <2>:                            Compiler flags.     (line   26)
* CFLAGS <3>:                            Compiler flags.     (line   28)
* CFLAGS <4>:                            Compiler flags.     (line   32)
* CFLAGS <5>:                            Compiler flags.     (line   54)
* CFLAGS <6>:                            Linker flags.       (line   18)
* CFLAGS_NODIST:                         Compiler flags.     (line   24)
* CFLAGS_NODIST <1>:                     Compiler flags.     (line   61)
* CFLAGS_NODIST <2>:                     Linker flags.       (line   26)
* cfmakecbreak() (in module tty):        tty — Terminal control functions.
                                                             (line   28)
* cfmakeraw() (in module tty):           tty — Terminal control functions.
                                                             (line   20)
* CFUNCTYPE() (in module ctypes):        Function prototypes.
                                                             (line   15)
* cget() (tkinter.font.Font method):     tkinter font — Tkinter font wrapper.
                                                             (line   51)
* cgi_directories (http.server.CGIHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  466)
* CGIHandler (class in wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line   11)
* CGIHTTPRequestHandler (class in http.server): http server — HTTP servers.
                                                             (line  441)
* CGIXMLRPCRequestHandler (class in xmlrpc.server): xmlrpc server — Basic XML-RPC servers.
                                                             (line   50)
* chain() (in module itertools):         Itertool Functions. (line  105)
* chaining; comparisons:                 Comparisons.        (line   19)
* chaining; comparisons <1>:             Comparisons<2>.     (line    6)
* ChainMap (class in collections):       ChainMap objects.   (line   16)
* ChainMap (class in typing):            Aliases to types in collections.
                                                             (line   28)
* change_cwd() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   82)
* CHANNEL_BINDING_TYPES (in module ssl): Constants<9>.       (line  471)
* CHAR_MAX (in module locale):           locale — Internationalization services.
                                                             (line  581)
* character:                             Immutable sequences.
                                                             (line   15)
* character <1>:                         Subscriptions.      (line   58)
* character <2>:                         unicodedata — Unicode Database.
                                                             (line    6)
* CharacterDataHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  327)
* characters_written (BlockingIOError attribute): OS exceptions.
                                                             (line   19)
* characters() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  126)
* charmap_build() (in module codecs):    codecs — Codec registry and base classes.
                                                             (line   45)
* Charset (class in email.charset):      email charset Representing character sets.
                                                             (line   24)
* charset() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   68)
* chdir() (in module contextlib):        Utilities.          (line  362)
* chdir() (in module os):                Files and Directories.
                                                             (line  116)
* check (lzma.LZMADecompressor attribute): Compressing and decompressing data in memory.
                                                             (line  157)
* check__all__() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  680)
* check_call() (in module subprocess):   Older high-level API.
                                                             (line   43)
* check_disallow_instantiation() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  734)
* CHECK_EG_MATCH (opcode):               Python Bytecode Instructions.
                                                             (line  476)
* CHECK_EXC_MATCH (opcode):              Python Bytecode Instructions.
                                                             (line  468)
* check_free_after_iterating() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  668)
* check_hostname (ssl.SSLContext attribute): SSL contexts.   (line  491)
* check_impl_detail() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  296)
* check_no_resource_warning() (in module test.support.warnings_helper): test support warnings_helper — Utilities for warnings tests.
                                                             (line   25)
* check_output() (doctest.OutputChecker method): OutputChecker objects.
                                                             (line   17)
* check_output() (in module subprocess): Older high-level API.
                                                             (line   80)
* check_returncode() (subprocess.CompletedProcess method): Using the subprocess Module.
                                                             (line  134)
* check_syntax_error() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  574)
* check_syntax_warning() (in module test.support.warnings_helper): test support warnings_helper — Utilities for warnings tests.
                                                             (line   32)
* check_unused_args() (string.Formatter method): Custom string formatting.
                                                             (line   90)
* check_warnings() (in module test.support.warnings_helper): test support warnings_helper — Utilities for warnings tests.
                                                             (line   47)
* check() (imaplib.IMAP4 method):        IMAP4 Objects.      (line   58)
* check() (in module tabnanny):          tabnanny — Detection of ambiguous indentation.
                                                             (line   17)
* checkcache() (in module linecache):    linecache — Random access to text lines.
                                                             (line   43)
* CHECKED_HASH (py_compile.PycInvalidationMode attribute): py_compile — Compile Python source files.
                                                             (line  109)
* checkfuncname() (in module bdb):       bdb — Debugger framework.
                                                             (line  449)
* checksizeof() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  450)
* checksum; Cyclic Redundancy Check:     zlib — Compression compatible with gzip.
                                                             (line  122)
* chflags() (in module os):              Files and Directories.
                                                             (line  135)
* chgat() (curses.window method):        Window Objects.     (line  138)
* childNodes (xml.dom.Node attribute):   Node Objects.       (line   49)
* ChildProcessError:                     OS exceptions.      (line   25)
* children (pyclbr.Class attribute):     Class Objects<2>.   (line   35)
* children (pyclbr.Function attribute):  Function Objects.   (line   34)
* children (tkinter.Tk attribute):       Tkinter Modules.    (line   86)
* chksum (tarfile.TarInfo attribute):    TarInfo Objects.    (line  137)
* chmod() (in module os):                Files and Directories.
                                                             (line  176)
* chmod() (pathlib.Path method):         Permissions and ownership.
                                                             (line   36)
* choice() (in module random):           Functions for sequences.
                                                             (line    6)
* choice() (in module secrets):          Random numbers.     (line   15)
* choices (optparse.Option attribute):   Option attributes.  (line   63)
* choices() (in module random):          Functions for sequences.
                                                             (line   11)
* Chooser (class in tkinter.colorchooser): tkinter colorchooser — Color choosing dialog.
                                                             (line   15)
* chown() (in module os):                Files and Directories.
                                                             (line  246)
* chown() (in module shutil):            Directory and files operations.
                                                             (line  401)
* chroot() (in module os):               Files and Directories.
                                                             (line  273)
* CHRTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  290)
* cipher() (ssl.SSLSocket method):       SSL sockets.        (line  231)
* circle() (in module turtle):           Turtle motion.      (line  211)
* CIRCUMFLEX (in module token):          token — Constants used with Python parse trees.
                                                             (line  251)
* CIRCUMFLEXEQUAL (in module token):     token — Constants used with Python parse trees.
                                                             (line  284)
* clamp (decimal.Context attribute):     Context objects.    (line  152)
* Clamped (class in decimal):            Signals.            (line   20)
* class:                                 Glossary.           (line  248)
* Class (class in pyclbr):               Class Objects<2>.   (line    6)
* Class (class in symtable):             Examining Symbol Tables.
                                                             (line  150)
* CLASS (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   19)
* class instance; attribute:             Class instances.    (line    6)
* class instance; attribute; assignment: Class instances.    (line   21)
* class instance; call:                  Calls.              (line  151)
* class object; call:                    Custom classes.     (line   19)
* class object; call <1>:                Custom classes.     (line   31)
* class object; call <2>:                Calls.              (line  147)
* class variable:                        Glossary.           (line  254)
* class; attribute:                      Custom classes.     (line   19)
* class; attribute; assignment:          Custom classes.     (line   28)
* class; body:                           Executing the class body.
                                                             (line    6)
* class; constructor:                    Basic customization.
                                                             (line   38)
* class; definition:                     The return statement.
                                                             (line    6)
* class; definition <1>:                 Class definitions.  (line    6)
* class; instance:                       Class instances.    (line    6)
* class; name:                           Class definitions.  (line    6)
* ClassDef (class in ast):               Function and class definitions.
                                                             (line  169)
* ClassMethodDescriptorType (in module types): Standard Interpreter Types.
                                                             (line  116)
* ClassVar (in module typing):           Special forms.      (line  193)
* clause:                                Compound statements.
                                                             (line   18)
* CLD_CONTINUED (in module os):          Process Management. (line 1043)
* CLD_DUMPED (in module os):             Process Management. (line 1043)
* CLD_EXITED (in module os):             Process Management. (line 1043)
* CLD_KILLED (in module os):             Process Management. (line 1043)
* CLD_STOPPED (in module os):            Process Management. (line 1043)
* CLD_TRAPPED (in module os):            Process Management. (line 1043)
* clean() (mailbox.Maildir method):      Maildir objects.    (line   86)
* cleandoc() (in module inspect):        Retrieving source code.
                                                             (line   71)
* CleanImport (class in test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   87)
* cleanup functions:                     Process Control.    (line   33)
* CLEANUP_THROW (opcode):                Python Bytecode Instructions.
                                                             (line  351)
* cleanup() (tempfile.TemporaryDirectory method): tempfile — Generate temporary files and directories.
                                                             (line  202)
* clear (pdb command):                   Debugger commands.  (line  126)
* Clear Breakpoint:                      Help menu Shell and Editor.
                                                             (line   30)
* clear_all_breaks() (bdb.Bdb method):   bdb — Debugger framework.
                                                             (line  363)
* clear_all_file_breaks() (bdb.Bdb method): bdb — Debugger framework.
                                                             (line  358)
* clear_bpbynumber() (bdb.Bdb method):   bdb — Debugger framework.
                                                             (line  352)
* clear_break() (bdb.Bdb method):        bdb — Debugger framework.
                                                             (line  347)
* clear_cache() (in module filecmp):     filecmp — File and Directory Comparisons.
                                                             (line   56)
* clear_cache() (zoneinfo.ZoneInfo class method): The ZoneInfo class.
                                                             (line   61)
* clear_content() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  672)
* clear_flags() (decimal.Context method): Context objects.   (line  183)
* clear_frames() (in module traceback):  Module-Level Functions<2>.
                                                             (line  177)
* clear_history() (in module readline):  History list.       (line    8)
* clear_overloads() (in module typing):  Functions and decorators.
                                                             (line  303)
* clear_session_cookies() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   90)
* clear_traces() (in module tracemalloc): Functions<11>.     (line    6)
* clear_traps() (decimal.Context method): Context objects.   (line  187)
* clear() (array.array method):          array — Efficient arrays of numeric values.
                                                             (line  226)
* clear() (asyncio.Event method):        Event.              (line   58)
* clear() (collections.deque method):    deque objects.      (line   43)
* clear() (curses.window method):        Window Objects.     (line  154)
* clear() (dict method):                 Mapping Types — dict.
                                                             (line  161)
* clear() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  668)
* clear() (frame method):                Frame object methods.
                                                             (line    8)
* clear() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   78)
* clear() (in module turtle):            More drawing control.
                                                             (line   23)
* clear() (mailbox.Mailbox method):      Mailbox objects.    (line  211)
* clear() (sequence method):             Mutable Sequence Types.
                                                             (line   74)
* clear() (set method):                  Set Types — set frozenset.
                                                             (line  215)
* clear() (threading.Event method):      Event objects.      (line   36)
* clear() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   58)
* clearcache() (in module linecache):    linecache — Random access to text lines.
                                                             (line   38)
* clearok() (curses.window method):      Window Objects.     (line  159)
* clearscreen() (in module turtle):      Window control.     (line   73)
* clearstamp() (in module turtle):       Turtle motion.      (line  290)
* clearstamps() (in module turtle):      Turtle motion.      (line  309)
* client_address (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   70)
* client_address (socketserver.BaseRequestHandler attribute): Request Handler Objects.
                                                             (line   47)
* Client() (in module multiprocessing.connection): Listeners and Clients.
                                                             (line   34)
* CLOCK_BOOTTIME (in module time):       Clock ID Constants. (line    9)
* clock_getres() (in module time):       Functions<5>.       (line   40)
* clock_gettime_ns() (in module time):   Functions<5>.       (line   63)
* clock_gettime() (in module time):      Functions<5>.       (line   50)
* CLOCK_HIGHRES (in module time):        Clock ID Constants. (line   23)
* CLOCK_MONOTONIC (in module time):      Clock ID Constants. (line   34)
* CLOCK_MONOTONIC_RAW (in module time):  Clock ID Constants. (line   43)
* CLOCK_MONOTONIC_RAW_APPROX (in module time): Clock ID Constants.
                                                             (line   52)
* CLOCK_PROCESS_CPUTIME_ID (in module time): Clock ID Constants.
                                                             (line   61)
* CLOCK_PROF (in module time):           Clock ID Constants. (line   69)
* CLOCK_REALTIME (in module time):       Clock ID Constants. (line  129)
* clock_seq (uuid.UUID attribute):       uuid — UUID objects according to RFC 4122.
                                                             (line  125)
* clock_seq_hi_variant (uuid.UUID attribute): uuid — UUID objects according to RFC 4122.
                                                             (line  113)
* clock_seq_low (uuid.UUID attribute):   uuid — UUID objects according to RFC 4122.
                                                             (line  116)
* clock_settime_ns() (in module time):   Functions<5>.       (line   84)
* clock_settime() (in module time):      Functions<5>.       (line   72)
* CLOCK_TAI (in module time):            Clock ID Constants. (line   77)
* CLOCK_THREAD_CPUTIME_ID (in module time): Clock ID Constants.
                                                             (line   89)
* CLOCK_UPTIME (in module time):         Clock ID Constants. (line   97)
* CLOCK_UPTIME_RAW (in module time):     Clock ID Constants. (line  107)
* CLOCK_UPTIME_RAW_APPROX (in module time): Clock ID Constants.
                                                             (line  117)
* CLONE_FILES (in module os):            Process Parameters. (line  619)
* CLONE_FS (in module os):               Process Parameters. (line  619)
* CLONE_NEWCGROUP (in module os):        Process Parameters. (line  619)
* CLONE_NEWIPC (in module os):           Process Parameters. (line  619)
* CLONE_NEWNET (in module os):           Process Parameters. (line  619)
* CLONE_NEWNS (in module os):            Process Parameters. (line  619)
* CLONE_NEWPID (in module os):           Process Parameters. (line  619)
* CLONE_NEWTIME (in module os):          Process Parameters. (line  619)
* CLONE_NEWUSER (in module os):          Process Parameters. (line  619)
* CLONE_NEWUTS (in module os):           Process Parameters. (line  619)
* CLONE_SIGHAND (in module os):          Process Parameters. (line  619)
* CLONE_SYSVSEM (in module os):          Process Parameters. (line  619)
* CLONE_THREAD (in module os):           Process Parameters. (line  619)
* CLONE_VM (in module os):               Process Parameters. (line  619)
* clone() (email.generator.BytesGenerator method): email generator Generating MIME documents.
                                                             (line  111)
* clone() (email.generator.Generator method): email generator Generating MIME documents.
                                                             (line  205)
* clone() (email.policy.Policy method):  email policy Policy Objects.
                                                             (line  223)
* clone() (in module turtle):            Special Turtle methods.
                                                             (line   32)
* cloneNode() (xml.dom.Node method):     Node Objects.       (line  147)
* close (in module os):                  Sub-interpreter support.
                                                             (line  196)
* close_clients() (asyncio.Server method): Server objects.   (line   44)
* close_connection (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   79)
* close() (asyncio.AbstractChildWatcher method): Process Watchers.
                                                             (line   81)
* close() (asyncio.BaseTransport method): Base Transport.    (line    6)
* close() (asyncio.loop method):         Running and stopping the loop.
                                                             (line   43)
* close() (asyncio.Runner method):       Runner context manager.
                                                             (line   49)
* close() (asyncio.Server method):       Server objects.     (line   32)
* close() (asyncio.StreamWriter method): StreamWriter.       (line   40)
* close() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   59)
* close() (contextlib.ExitStack method): Utilities.          (line  613)
* close() (coroutine method):            Coroutine Objects.  (line   50)
* close() (dbm.dumb.dumbdbm method):     dbm dumb — Portable DBM implementation.
                                                             (line   79)
* close() (dbm.gnu.gdbm method):         dbm gnu — GNU database manager.
                                                             (line   96)
* close() (dbm.ndbm.ndbm method):        dbm ndbm — New Database Manager.
                                                             (line   82)
* close() (dbm.sqlite3.sqlite3 method):  dbm sqlite3 — SQLite backend for dbm.
                                                             (line   54)
* close() (email.parser.BytesFeedParser method): FeedParser API.
                                                             (line   64)
* close() (file method):                 I/O objects also known as file objects.
                                                             (line   31)
* close() (ftplib.FTP method):           FTP objects.        (line  368)
* close() (generator method):            Generator-iterator methods.
                                                             (line   64)
* close() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   15)
* close() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  157)
* close() (imaplib.IMAP4 method):        IMAP4 Objects.      (line   62)
* close() (in module fileinput):         fileinput — Iterate over lines from multiple input streams.
                                                             (line  132)
* close() (in module os):                File Descriptor Operations.
                                                             (line   21)
* close() (in module socket):            Other functions<2>. (line    8)
* close() (io.IOBase method):            I/O Base Classes.   (line   47)
* close() (logging.FileHandler method):  FileHandler.        (line   26)
* close() (logging.Handler method):      Handler Objects.    (line   74)
* close() (logging.handlers.MemoryHandler method): MemoryHandler.
                                                             (line   56)
* close() (logging.handlers.NTEventLogHandler method): NTEventLogHandler.
                                                             (line   29)
* close() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   20)
* close() (logging.handlers.SysLogHandler method): SysLogHandler.
                                                             (line   46)
* close() (mailbox.Mailbox method):      Mailbox objects.    (line  268)
* close() (mailbox.Maildir method):      Maildir objects.    (line  215)
* close() (mailbox.MH method):           MH objects.         (line  107)
* close() (mmap.mmap method):            mmap — Memory-mapped file support.
                                                             (line  182)
* close() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   35)
* close() (multiprocessing.connection.Listener method): Listeners and Clients.
                                                             (line   91)
* close() (multiprocessing.pool.Pool method): Process Pools. (line  174)
* close() (multiprocessing.Process method): Process and exceptions.
                                                             (line  228)
* close() (multiprocessing.Queue method): Pipes and Queues.  (line  176)
* close() (multiprocessing.shared_memory.SharedMemory method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line   93)
* close() (multiprocessing.SimpleQueue method): Pipes and Queues.
                                                             (line  230)
* close() (os.scandir method):           Files and Directories.
                                                             (line  875)
* close() (select.devpoll method):       /dev/poll Polling Objects.
                                                             (line   12)
* close() (select.epoll method):         Edge and Level Trigger Polling epoll Objects.
                                                             (line   65)
* close() (select.kqueue method):        Kqueue Objects.     (line    6)
* close() (selectors.BaseSelector method): Classes<4>.       (line  137)
* close() (shelve.Shelf method):         shelve — Python object persistence.
                                                             (line   76)
* close() (socket.socket method):        Socket Objects.     (line   41)
* close() (sqlite3.Blob method):         Blob objects.       (line   37)
* close() (sqlite3.Connection method):   Connection objects. (line   88)
* close() (sqlite3.Cursor method):       Cursor objects.     (line  155)
* close() (tarfile.TarFile method):      TarFile Objects.    (line  323)
* close() (urllib.request.BaseHandler method): BaseHandler Objects.
                                                             (line   14)
* close() (wave.Wave_read method):       Wave_read Objects.  (line   13)
* close() (wave.Wave_write method):      Wave_write Objects. (line   29)
* Close() (winreg.PyHKEY method):        Registry Handle Objects.
                                                             (line   30)
* close() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   28)
* close() (xml.etree.ElementTree.XMLParser method): XMLParser Objects.
                                                             (line   20)
* close() (xml.etree.ElementTree.XMLPullParser method): XMLPullParser Objects.
                                                             (line   40)
* close() (xml.sax.xmlreader.IncrementalParser method): IncrementalParser Objects.
                                                             (line   13)
* close() (zipfile.ZipFile method):      ZipFile objects.    (line  106)
* CloseBoundaryNotFoundDefect:           email errors Exception and Defect classes.
                                                             (line   85)
* closed (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   75)
* closed (io.IOBase attribute):          I/O Base Classes.   (line   57)
* closed (mmap.mmap attribute):          mmap — Memory-mapped file support.
                                                             (line  188)
* closed (select.devpoll attribute):     /dev/poll Polling Objects.
                                                             (line   18)
* closed (select.epoll attribute):       Edge and Level Trigger Polling epoll Objects.
                                                             (line   69)
* closed (select.kqueue attribute):      Kqueue Objects.     (line   10)
* CloseKey() (in module winreg):         Functions<13>.      (line    8)
* closelog() (in module syslog):         syslog — Unix syslog library routines.
                                                             (line   76)
* closerange() (in module os):           File Descriptor Operations.
                                                             (line   32)
* closing() (in module contextlib):      Utilities.          (line  149)
* closure variable:                      Glossary.           (line  259)
* clrtobot() (curses.window method):     Window Objects.     (line  164)
* clrtoeol() (curses.window method):     Window Objects.     (line  170)
* Cmd (class in cmd):                    cmd — Support for line-oriented command interpreters.
                                                             (line   15)
* cmd (subprocess.CalledProcessError attribute): Using the subprocess Module.
                                                             (line  216)
* cmd (subprocess.TimeoutExpired attribute): Using the subprocess Module.
                                                             (line  173)
* cmdloop() (cmd.Cmd method):            Cmd Objects.        (line    8)
* cmdqueue (cmd.Cmd attribute):          Cmd Objects.        (line  142)
* cmp_op (in module dis):                Opcode collections. (line   21)
* cmp_to_key() (in module functools):    functools — Higher-order functions and operations on callable objects.
                                                             (line  117)
* cmp() (in module filecmp):             filecmp — File and Directory Comparisons.
                                                             (line   16)
* cmpfiles() (in module filecmp):        filecmp — File and Directory Comparisons.
                                                             (line   36)
* CMSG_LEN() (in module socket):         Other functions<2>. (line  334)
* CMSG_SPACE() (in module socket):       Other functions<2>. (line  351)
* co_argcount (code object attribute):   Code objects.       (line   16)
* co_argcount (codeobject attribute):    Special read-only attributes<2>.
                                                             (line   14)
* CO_ASYNC_GENERATOR (C macro):          Code Object Flags.  (line   48)
* CO_ASYNC_GENERATOR (in module inspect): Code Objects Bit Flags.
                                                             (line   52)
* co_cellvars (code object attribute):   Code objects.       (line   16)
* co_cellvars (codeobject attribute):    Special read-only attributes<2>.
                                                             (line   39)
* co_code (code object attribute):       Code objects.       (line   16)
* co_code (codeobject attribute):        Special read-only attributes<2>.
                                                             (line   54)
* co_consts (code object attribute):     Code objects.       (line   16)
* co_consts (codeobject attribute):      Special read-only attributes<2>.
                                                             (line   58)
* CO_COROUTINE (C macro):                Code Object Flags.  (line   42)
* CO_COROUTINE (in module inspect):      Code Objects Bit Flags.
                                                             (line   35)
* co_filename (code object attribute):   Code objects.       (line   16)
* co_filename (codeobject attribute):    Special read-only attributes<2>.
                                                             (line   66)
* co_firstlineno (code object attribute): Code objects.      (line   16)
* co_firstlineno (codeobject attribute): Special read-only attributes<2>.
                                                             (line   70)
* co_flags (code object attribute):      Code objects.       (line   16)
* co_flags (codeobject attribute):       Special read-only attributes<2>.
                                                             (line   85)
* co_freevars (code object attribute):   Code objects.       (line   16)
* co_freevars (codeobject attribute):    Special read-only attributes<2>.
                                                             (line   45)
* CO_FUTURE_ABSOLUTE_IMPORT (C macro):   Code Object Flags.  (line   54)
* CO_FUTURE_ANNOTATIONS (C macro):       Code Object Flags.  (line   69)
* CO_FUTURE_DIVISION (C macro):          Code Object Flags.  (line   51)
* CO_FUTURE_GENERATOR_STOP (C macro):    Code Object Flags.  (line   66)
* CO_FUTURE_PRINT_FUNCTION (C macro):    Code Object Flags.  (line   60)
* CO_FUTURE_UNICODE_LITERALS (C macro):  Code Object Flags.  (line   63)
* CO_FUTURE_WITH_STATEMENT (C macro):    Code Object Flags.  (line   57)
* CO_GENERATOR (C macro):                Code Object Flags.  (line   39)
* CO_GENERATOR (in module inspect):      Code Objects Bit Flags.
                                                             (line   30)
* CO_ITERABLE_COROUTINE (C macro):       Code Object Flags.  (line   45)
* CO_ITERABLE_COROUTINE (in module inspect): Code Objects Bit Flags.
                                                             (line   43)
* co_kwonlyargcount (code object attribute): Code objects.   (line   16)
* co_kwonlyargcount (codeobject attribute): Special read-only attributes<2>.
                                                             (line   25)
* co_lines() (codeobject method):        Methods on code objects.
                                                             (line   43)
* co_lnotab (code object attribute):     Code objects.       (line   16)
* co_lnotab (codeobject attribute):      Special read-only attributes<2>.
                                                             (line   73)
* co_name (code object attribute):       Code objects.       (line   16)
* co_name (codeobject attribute):        Special read-only attributes<2>.
                                                             (line    6)
* co_names (code object attribute):      Code objects.       (line   16)
* co_names (codeobject attribute):       Special read-only attributes<2>.
                                                             (line   62)
* CO_NESTED (C macro):                   Code Object Flags.  (line   36)
* CO_NESTED (in module inspect):         Code Objects Bit Flags.
                                                             (line   26)
* CO_NEWLOCALS (C macro):                Code Object Flags.  (line   27)
* CO_NEWLOCALS (in module inspect):      Code Objects Bit Flags.
                                                             (line   13)
* co_nlocals (code object attribute):    Code objects.       (line   16)
* co_nlocals (codeobject attribute):     Special read-only attributes<2>.
                                                             (line   30)
* CO_OPTIMIZED (C macro):                Code Object Flags.  (line   24)
* CO_OPTIMIZED (in module inspect):      Code Objects Bit Flags.
                                                             (line    9)
* co_positions() (codeobject method):    Methods on code objects.
                                                             (line    6)
* co_posonlyargcount (code object attribute): Code objects.  (line   16)
* co_posonlyargcount (codeobject attribute): Special read-only attributes<2>.
                                                             (line   20)
* co_qualname (code object attribute):   Code objects.       (line   16)
* co_qualname (codeobject attribute):    Special read-only attributes<2>.
                                                             (line    9)
* co_stacksize (code object attribute):  Code objects.       (line   16)
* co_stacksize (codeobject attribute):   Special read-only attributes<2>.
                                                             (line   82)
* CO_VARARGS (C macro):                  Code Object Flags.  (line   30)
* CO_VARARGS (in module inspect):        Code Objects Bit Flags.
                                                             (line   18)
* CO_VARKEYWORDS (C macro):              Code Object Flags.  (line   33)
* CO_VARKEYWORDS (in module inspect):    Code Objects Bit Flags.
                                                             (line   22)
* co_varnames (code object attribute):   Code objects.       (line   16)
* co_varnames (codeobject attribute):    Special read-only attributes<2>.
                                                             (line   34)
* code (SystemExit attribute):           Concrete exceptions.
                                                             (line  405)
* code (urllib.error.HTTPError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   41)
* code (urllib.response.addinfourl attribute): urllib response — Response classes used by urllib.
                                                             (line   40)
* code (xml.etree.ElementTree.ParseError attribute): Exceptions<19>.
                                                             (line   14)
* code (xml.parsers.expat.ExpatError attribute): ExpatError Exceptions.
                                                             (line    9)
* code object:                           Code objects.       (line    6)
* code object <1>:                       Methods.            (line   43)
* code object <2>:                       marshal — Internal Python object serialization.
                                                             (line   33)
* code object <3>:                       Cell Objects.       (line   57)
* code_context (inspect.FrameInfo attribute): The interpreter stack.
                                                             (line   32)
* code_context (inspect.Traceback attribute): The interpreter stack.
                                                             (line   72)
* code_info() (in module dis):           Analysis functions. (line   11)
* code; block:                           Execution model.    (line    6)
* Codec (class in codecs):               Stateless Encoding and Decoding.
                                                             (line    9)
* CodecInfo (class in codecs):           codecs — Codec registry and base classes.
                                                             (line   67)
* CodecRegistryError:                    encodings — Encodings package.
                                                             (line   41)
* Codecs:                                codecs — Codec registry and base classes.
                                                             (line    8)
* Codecs; decode:                        codecs — Codec registry and base classes.
                                                             (line    8)
* Codecs; encode:                        codecs — Codec registry and base classes.
                                                             (line    8)
* codecs.escape_decode() (in module codecs): Standalone Codec Functions.
                                                             (line   22)
* codecs.escape_encode() (in module codecs): Standalone Codec Functions.
                                                             (line   12)
* coded_value (http.cookies.Morsel attribute): Morsel Objects.
                                                             (line   53)
* codepoint2name (in module html.entities): html entities — Definitions of HTML general entities.
                                                             (line   35)
* codes (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   16)
* CODESET (in module locale):            locale — Internationalization services.
                                                             (line  197)
* CodeType (class in types):             Standard Interpreter Types.
                                                             (line   56)
* coding; style:                         Intermezzo Coding Style.
                                                             (line    6)
* col_offset (ast.AST attribute):        Node classes.       (line   50)
* collapse_addresses() (in module ipaddress): Other Module Level Functions.
                                                             (line   43)
* collapse_rfc2231_value() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  199)
* collect() (in module gc):              gc — Garbage Collector interface.
                                                             (line   34)
* collectedDurations (unittest.TestResult attribute): Loading and running tests.
                                                             (line  274)
* Collection (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   36)
* Collection (class in typing):          Aliases to container ABCs in collections abc.
                                                             (line   37)
* colno (json.JSONDecodeError attribute): Exceptions<17>.    (line   27)
* colno (re.PatternError attribute):     Exceptions<3>.      (line   32)
* colno (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   57)
* COLON (in module token):               token — Constants used with Python parse trees.
                                                             (line  188)
* colon (mailbox.Maildir attribute):     Maildir objects.    (line   45)
* COLONEQUAL (in module token):          token — Constants used with Python parse trees.
                                                             (line  314)
* COLOR_BLACK (in module curses):        Constants<6>.       (line  639)
* COLOR_BLUE (in module curses):         Constants<6>.       (line  642)
* color_content() (in module curses):    Functions<6>.       (line   45)
* COLOR_CYAN (in module curses):         Constants<6>.       (line  645)
* COLOR_GREEN (in module curses):        Constants<6>.       (line  648)
* COLOR_MAGENTA (in module curses):      Constants<6>.       (line  651)
* color_pair() (in module curses):       Functions<6>.       (line   53)
* COLOR_PAIRS (in module curses):        Constants<6>.       (line   39)
* COLOR_RED (in module curses):          Constants<6>.       (line  654)
* COLOR_WHITE (in module curses):        Constants<6>.       (line  657)
* COLOR_YELLOW (in module curses):       Constants<6>.       (line  660)
* color() (in module turtle):            Color control.      (line  112)
* colormode() (in module turtle):        Settings and special methods.
                                                             (line   34)
* COLORS (in module curses):             Constants<6>.       (line   34)
* COLS (in module curses):               Constants<6>.       (line   44)
* column() (tkinter.ttk.Treeview method): ttk Treeview.      (line   35)
* columnize() (cmd.Cmd method):          Cmd Objects.        (line   87)
* COLUMNS:                               Functions<6>.       (line  593)
* COLUMNS <1>:                           Functions<6>.       (line  596)
* columns (os.terminal_size attribute):  Querying the size of a terminal.
                                                             (line   30)
* comb() (in module math):               Number-theoretic functions.
                                                             (line    6)
* combinations_with_replacement() (in module itertools): Itertool Functions.
                                                             (line  170)
* combinations() (in module itertools):  Itertool Functions. (line  128)
* combine() (datetime.datetime class method): datetime Objects.
                                                             (line  179)
* combining() (in module unicodedata):   unicodedata — Unicode Database.
                                                             (line  101)
* Combobox (class in tkinter.ttk):       ttk Combobox.       (line    6)
* comma:                                 Parenthesized forms.
                                                             (line   20)
* COMMA (in module token):               token — Constants used with Python parse trees.
                                                             (line  191)
* command (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   92)
* command line:                          Complete Python programs.
                                                             (line   25)
* command line option; -?:               Generic options.    (line    6)
* command line option; -b:               Miscellaneous options.
                                                             (line    6)
* command line option; -B:               Miscellaneous options.
                                                             (line   16)
* command line option; -build:           Cross Compiling Options.
                                                             (line   12)
* command line option; -c:               Interface options.  (line   37)
* command line option; -check-hash-based-pycs: Miscellaneous options.
                                                             (line   21)
* command line option; -d:               Miscellaneous options.
                                                             (line   35)
* command line option; -disable-gil:     General Options.    (line  224)
* command line option; -disable-ipv6:    General Options.    (line   16)
* command line option; -disable-test-modules: Install Options.
                                                             (line   24)
* command line option; -E:               Miscellaneous options.
                                                             (line   43)
* command line option; -enable-big-digits: General Options.  (line   21)
* command line option; -enable-bolt:     Performance options.
                                                             (line   62)
* command line option; -enable-experimental-jit: General Options.
                                                             (line  236)
* command line option; -enable-framework: macOS Options.     (line   15)
* command line option; -enable-framework <1>: macOS Options. (line   17)
* command line option; -enable-framework <2>: iOS Options.   (line    8)
* command line option; -enable-loadable-sqlite-extensions: General Options.
                                                             (line    6)
* command line option; -enable-optimizations: Performance options.
                                                             (line   10)
* command line option; -enable-profiling: Performance options.
                                                             (line  128)
* command line option; -enable-pystats:  General Options.    (line  131)
* command line option; -enable-shared:   Linker options<2>.  (line    6)
* command line option; -enable-universalsdk: macOS Options.  (line    8)
* command line option; -enable-universalsdk <1>: macOS Options.
                                                             (line   10)
* command line option; -enable-wasm-dynamic-linking: WebAssembly Options.
                                                             (line   16)
* command line option; -enable-wasm-pthreads: WebAssembly Options.
                                                             (line   26)
* command line option; -exec-prefix:     Install Options.    (line   16)
* command line option; -h:               Generic options.    (line    6)
* command line option; -help:            Generic options.    (line    6)
* command line option; -help-all:        Generic options.    (line   27)
* command line option; -help-env:        Generic options.    (line   13)
* command line option; -help-xoptions:   Generic options.    (line   20)
* command line option; -host:            Cross Compiling Options.
                                                             (line   16)
* command line option; -i:               Miscellaneous options.
                                                             (line   50)
* command line option; -I:               Miscellaneous options.
                                                             (line   71)
* command line option; -J:               Options you shouldn’t use.
                                                             (line    6)
* command line option; -m:               Interface options.  (line   51)
* command line option; -O:               Miscellaneous options.
                                                             (line   83)
* command line option; -OO:              Miscellaneous options.
                                                             (line   93)
* command line option; -P:               Miscellaneous options.
                                                             (line  102)
* command line option; -prefix:          Install Options.    (line    6)
* command line option; -q:               Miscellaneous options.
                                                             (line  121)
* command line option; -R:               Miscellaneous options.
                                                             (line  128)
* command line option; -s:               Miscellaneous options.
                                                             (line  154)
* command line option; -S:               Miscellaneous options.
                                                             (line  166)
* command line option; -u:               Miscellaneous options.
                                                             (line  174)
* command line option; -V:               Generic options.    (line   33)
* command line option; -v:               Miscellaneous options.
                                                             (line  184)
* command line option; -version:         Generic options.    (line   33)
* command line option; -W:               Miscellaneous options.
                                                             (line  197)
* command line option; -with-address-sanitizer: Debug options.
                                                             (line   59)
* command line option; -with-app-store-compliance: macOS Options.
                                                             (line   56)
* command line option; -with-app-store-compliance <1>: macOS Options.
                                                             (line   58)
* command line option; -with-assertions: Debug options.      (line   34)
* command line option; -with-build-python: Cross Compiling Options.
                                                             (line   20)
* command line option; -with-builtin-hashlib-hashes: Security Options.
                                                             (line   21)
* command line option; -with-computed-gotos: Performance options.
                                                             (line   99)
* command line option; -with-dbmliborder: General Options.   (line   68)
* command line option; -with-dtrace:     Debug options.      (line   51)
* command line option; -with-emscripten-target: WebAssembly Options.
                                                             (line    6)
* command line option; -with-ensurepip:  Install Options.    (line   32)
* command line option; -with-framework-name: macOS Options.  (line   51)
* command line option; -with-framework-name <1>: iOS Options.
                                                             (line   13)
* command line option; -with-hash-algorithm: Security Options.
                                                             (line    6)
* command line option; -with-libc:       Libraries options.  (line   58)
* command line option; -with-libm:       Libraries options.  (line   53)
* command line option; -with-libs:       Libraries options.  (line    6)
* command line option; -with-lto:        Performance options.
                                                             (line   46)
* command line option; -with-memory-sanitizer: Debug options.
                                                             (line   69)
* command line option; -with-openssl:    Libraries options.  (line   63)
* command line option; -with-openssl-rpath: Libraries options.
                                                             (line   69)
* command line option; -with-pkg-config: General Options.    (line  118)
* command line option; -with-platlibdir: General Options.    (line   96)
* command line option; -with-pydebug:    Debug options.      (line    6)
* command line option; -with-readline:   Libraries options.  (line   35)
* command line option; -with-ssl-default-suites: Security Options.
                                                             (line   40)
* command line option; -with-strict-overflow: Performance options.
                                                             (line  132)
* command line option; -with-suffix:     General Options.    (line   32)
* command line option; -with-system-expat: Libraries options.
                                                             (line   10)
* command line option; -with-system-libmpdec: Libraries options.
                                                             (line   15)
* command line option; -with-thread-sanitizer: Debug options.
                                                             (line   83)
* command line option; -with-trace-refs: Debug options.      (line   11)
* command line option; -with-tzpath:     General Options.    (line   44)
* command line option; -with-undefined-behavior-sanitizer: Debug options.
                                                             (line   76)
* command line option; -with-universal-archs: macOS Options. (line   23)
* command line option; -with-valgrind:   Debug options.      (line   47)
* command line option; -with-wheel-pkg-dir: General Options. (line  106)
* command line option; -without-c-locale-coercion: General Options.
                                                             (line   81)
* command line option; -without-decimal-contextvar: General Options.
                                                             (line   57)
* command line option; -without-doc-strings: Performance options.
                                                             (line  118)
* command line option; -without-freelists: General Options.  (line   90)
* command line option; -without-mimalloc: Performance options.
                                                             (line  104)
* command line option; -without-pymalloc: Performance options.
                                                             (line  111)
* command line option; -without-readline: Libraries options. (line   45)
* command line option; -without-static-libpython: Linker options<2>.
                                                             (line   11)
* command line option; -x:               Miscellaneous options.
                                                             (line  258)
* command line option; -X:               Miscellaneous options.
                                                             (line  263)
* command line option; BOLT_APPLY_FLAGS: Performance options.
                                                             (line   87)
* command line option; BOLT_INSTRUMENT_FLAGS: Performance options.
                                                             (line   93)
* command line option; BZIP2_CFLAGS:     Options for third-party dependencies.
                                                             (line    8)
* command line option; BZIP2_LIBS:       Options for third-party dependencies.
                                                             (line   10)
* command line option; CC:               C compiler options. (line    6)
* command line option; CFLAGS:           C compiler options. (line   10)
* command line option; CONFIG_SITE:      Cross Compiling Options.
                                                             (line   26)
* command line option; CPP:              C compiler options. (line   14)
* command line option; CPPFLAGS:         C compiler options. (line   18)
* command line option; CURSES_CFLAGS:    Options for third-party dependencies.
                                                             (line   15)
* command line option; CURSES_LIBS:      Options for third-party dependencies.
                                                             (line   17)
* command line option; GDBM_CFLAGS:      Options for third-party dependencies.
                                                             (line   22)
* command line option; GDBM_LIBS:        Options for third-party dependencies.
                                                             (line   24)
* command line option; HOSTRUNNER:       Cross Compiling Options.
                                                             (line   38)
* command line option; LDFLAGS:          Linker options.     (line    6)
* command line option; LIBB2_CFLAGS:     Options for third-party dependencies.
                                                             (line   28)
* command line option; LIBB2_LIBS:       Options for third-party dependencies.
                                                             (line   30)
* command line option; LIBEDIT_CFLAGS:   Options for third-party dependencies.
                                                             (line   35)
* command line option; LIBEDIT_LIBS:     Options for third-party dependencies.
                                                             (line   37)
* command line option; LIBFFI_CFLAGS:    Options for third-party dependencies.
                                                             (line   42)
* command line option; LIBFFI_LIBS:      Options for third-party dependencies.
                                                             (line   44)
* command line option; LIBLZMA_CFLAGS:   Options for third-party dependencies.
                                                             (line   59)
* command line option; LIBLZMA_LIBS:     Options for third-party dependencies.
                                                             (line   61)
* command line option; LIBMPDEC_CFLAGS:  Options for third-party dependencies.
                                                             (line   49)
* command line option; LIBMPDEC_LIBS:    Options for third-party dependencies.
                                                             (line   51)
* command line option; LIBREADLINE_CFLAGS: Options for third-party dependencies.
                                                             (line   66)
* command line option; LIBREADLINE_LIBS: Options for third-party dependencies.
                                                             (line   68)
* command line option; LIBS:             Linker options.     (line   10)
* command line option; LIBSQLITE3_CFLAGS: Options for third-party dependencies.
                                                             (line   73)
* command line option; LIBSQLITE3_LIBS:  Options for third-party dependencies.
                                                             (line   75)
* command line option; LIBUUID_CFLAGS:   Options for third-party dependencies.
                                                             (line   80)
* command line option; LIBUUID_LIBS:     Options for third-party dependencies.
                                                             (line   82)
* command line option; MACHDEP:          Linker options.     (line   14)
* command line option; PANEL_CFLAGS:     Options for third-party dependencies.
                                                             (line   87)
* command line option; PANEL_LIBS:       Options for third-party dependencies.
                                                             (line   89)
* command line option; PKG_CONFIG:       General Options.    (line  258)
* command line option; PKG_CONFIG_LIBDIR: General Options.   (line  262)
* command line option; PKG_CONFIG_PATH:  General Options.    (line  264)
* command line option; TCLTK_CFLAGS:     Options for third-party dependencies.
                                                             (line   96)
* command line option; TCLTK_LIBS:       Options for third-party dependencies.
                                                             (line   98)
* command line option; ZLIB_CFLAGS:      Options for third-party dependencies.
                                                             (line  102)
* command line option; ZLIB_LIBS:        Options for third-party dependencies.
                                                             (line  104)
* CommandCompiler (class in codeop):     codeop — Compile Python code.
                                                             (line   65)
* commands (pdb command):                Debugger commands.  (line  160)
* comment:                               Comments.           (line    6)
* comment (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   61)
* comment (http.cookies.Morsel attribute): Morsel Objects.   (line   13)
* COMMENT (in module token):             token — Constants used with Python parse trees.
                                                             (line   71)
* comment (zipfile.ZipFile attribute):   ZipFile objects.    (line  359)
* comment (zipfile.ZipInfo attribute):   ZipInfo objects.    (line  103)
* comment_url (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   66)
* Comment() (in module xml.etree.ElementTree): Functions<9>. (line   72)
* comment() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   49)
* comment() (xml.sax.handler.LexicalHandler method): LexicalHandler Objects.
                                                             (line   18)
* commenters (shlex.shlex attribute):    shlex Objects.      (line   85)
* CommentHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  385)
* commit() (sqlite3.Connection method):  Connection objects. (line   72)
* common (filecmp.dircmp attribute):     The dircmp class.   (line   63)
* Common Vulnerabilities and Exposures; CVE 2008-5983: Build and C API Changes<8>.
                                                             (line   77)
* Common Vulnerabilities and Exposures; CVE 2008-5983 <1>: Build and C API Changes<9>.
                                                             (line   47)
* Common Vulnerabilities and Exposures; CVE 2008-5983 <2>: Process-wide parameters.
                                                             (line  256)
* Common Vulnerabilities and Exposures; CVE 2012-0876: Security<46>.
                                                             (line   23)
* Common Vulnerabilities and Exposures; CVE 2012-0876 <1>: Security<49>.
                                                             (line   14)
* Common Vulnerabilities and Exposures; CVE 2012-0876 <2>: Security<55>.
                                                             (line   14)
* Common Vulnerabilities and Exposures; CVE 2013-0340: Security<26>.
                                                             (line   22)
* Common Vulnerabilities and Exposures; CVE 2013-1753: Library<183>.
                                                             (line  193)
* Common Vulnerabilities and Exposures; CVE 2014-0224: PEP 466 Network Security Enhancements for Python 2 7.
                                                             (line   30)
* Common Vulnerabilities and Exposures; CVE 2014-4616: Library<183>.
                                                             (line 1122)
* Common Vulnerabilities and Exposures; CVE 2015-1283: Security<52>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2015-1283 <1>: Security<57>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2016-0718: Security<46>.
                                                             (line   22)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <1>: Security<46>.
                                                             (line   23)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <2>: Security<46>.
                                                             (line   35)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <3>: Security<49>.
                                                             (line   13)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <4>: Security<49>.
                                                             (line   14)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <5>: Security<50>.
                                                             (line    7)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <6>: Security<55>.
                                                             (line   13)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <7>: Security<55>.
                                                             (line   14)
* Common Vulnerabilities and Exposures; CVE 2016-0718 <8>: Security<55>.
                                                             (line   26)
* Common Vulnerabilities and Exposures; CVE 2016-0772: Security<52>.
                                                             (line    8)
* Common Vulnerabilities and Exposures; CVE 2016-0772 <1>: Security<57>.
                                                             (line    8)
* Common Vulnerabilities and Exposures; CVE 2016-1000110: Library<162>.
                                                             (line   82)
* Common Vulnerabilities and Exposures; CVE 2016-1000110 <1>: Library<169>.
                                                             (line  267)
* Common Vulnerabilities and Exposures; CVE 2016-2183: Library<161>.
                                                             (line  178)
* Common Vulnerabilities and Exposures; CVE 2016-2183 <1>: Library<169>.
                                                             (line  205)
* Common Vulnerabilities and Exposures; CVE 2016-3189: Windows<29>.
                                                             (line   25)
* Common Vulnerabilities and Exposures; CVE 2016-4472: Security<46>.
                                                             (line   35)
* Common Vulnerabilities and Exposures; CVE 2016-4472 <1>: Security<50>.
                                                             (line    7)
* Common Vulnerabilities and Exposures; CVE 2016-4472 <2>: Security<55>.
                                                             (line   26)
* Common Vulnerabilities and Exposures; CVE 2016-5300: Security<46>.
                                                             (line   24)
* Common Vulnerabilities and Exposures; CVE 2016-5300 <1>: Security<49>.
                                                             (line   15)
* Common Vulnerabilities and Exposures; CVE 2016-5300 <2>: Security<55>.
                                                             (line   15)
* Common Vulnerabilities and Exposures; CVE 2016-9063: Security<46>.
                                                             (line   21)
* Common Vulnerabilities and Exposures; CVE 2016-9063 <1>: Security<49>.
                                                             (line   12)
* Common Vulnerabilities and Exposures; CVE 2016-9063 <2>: Security<55>.
                                                             (line   12)
* Common Vulnerabilities and Exposures; CVE 2017-1000158: Security<54>.
                                                             (line   21)
* Common Vulnerabilities and Exposures; CVE 2017-9233: Security<46>.
                                                             (line   20)
* Common Vulnerabilities and Exposures; CVE 2017-9233 <1>: Security<49>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2017-9233 <2>: Security<55>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2018-1060: Security<43>.
                                                             (line   48)
* Common Vulnerabilities and Exposures; CVE 2018-1060 <1>: Security<44>.
                                                             (line   15)
* Common Vulnerabilities and Exposures; CVE 2018-1060 <2>: Security<47>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2018-1061: Security<43>.
                                                             (line   49)
* Common Vulnerabilities and Exposures; CVE 2018-1061 <1>: Security<44>.
                                                             (line   16)
* Common Vulnerabilities and Exposures; CVE 2018-1061 <2>: Security<47>.
                                                             (line   12)
* Common Vulnerabilities and Exposures; CVE 2018-14647: Security<43>.
                                                             (line   26)
* Common Vulnerabilities and Exposures; CVE 2018-25032: Windows<29>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2018-8970: Security<43>.
                                                             (line   38)
* Common Vulnerabilities and Exposures; CVE 2018-8970 <1>: Security<44>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2019-12900: Windows<29>.
                                                             (line   26)
* Common Vulnerabilities and Exposures; CVE 2019-15903: Security<39>.
                                                             (line   20)
* Common Vulnerabilities and Exposures; CVE 2019-18348: Security<36>.
                                                             (line    7)
* Common Vulnerabilities and Exposures; CVE 2019-20907: Library<126>.
                                                             (line  186)
* Common Vulnerabilities and Exposures; CVE 2019-5010: Security<43>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2019-9740: Security<41>.
                                                             (line    9)
* Common Vulnerabilities and Exposures; CVE 2019-9948: Security<40>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2020-10735: Other CPython Implementation Changes.
                                                             (line   56)
* Common Vulnerabilities and Exposures; CVE 2020-10735 <1>: Notable security feature in 3 10 7.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2020-10735 <2>: Notable security feature in 3 9 14.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2020-10735 <3>: Notable security feature in 3 8 14.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2020-10735 <4>: Notable security feature in 3 7 14.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2020-10735 <5>: Integer string conversion length limitation.
                                                             (line   20)
* Common Vulnerabilities and Exposures; CVE 2020-15523: Security<33>.
                                                             (line   13)
* Common Vulnerabilities and Exposures; CVE 2020-15801: Security<33>.
                                                             (line    7)
* Common Vulnerabilities and Exposures; CVE 2020-8492: Security<35>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2021-3426: Security<28>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2022-26488: Windows<29>.
                                                             (line   28)
* Common Vulnerabilities and Exposures; CVE 2022-37434: Windows<26>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2022-42919: Security<24>.
                                                             (line   24)
* Common Vulnerabilities and Exposures; CVE 2022-4303: Security<20>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2022-4303 <1>: Security<20>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2023-0286: Security<20>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2023-24329: Security<19>.
                                                             (line   19)
* Common Vulnerabilities and Exposures; CVE 2023-27043: email.
                                                             (line   22)
* Common Vulnerabilities and Exposures; CVE 2023-27043 <1>: Library<37>.
                                                             (line  429)
* Common Vulnerabilities and Exposures; CVE 2023-40217: Security<18>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2023-52425: xml. (line    6)
* Common Vulnerabilities and Exposures; CVE 2023-52425 <1>: Security<15>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2023-52425 <2>: Documentation<15>.
                                                             (line    6)
* Common Vulnerabilities and Exposures; CVE 2023-52425 <3>: XML security.
                                                             (line   57)
* Common Vulnerabilities and Exposures; CVE 2024-12718: tarfile.
                                                             (line   12)
* Common Vulnerabilities and Exposures; CVE 2024-12718 <1>: tarfile.
                                                             (line   20)
* Common Vulnerabilities and Exposures; CVE 2024-12718 <2>: Security<7>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2024-4030: os.   (line   38)
* Common Vulnerabilities and Exposures; CVE 2024-4030 <1>: tempfile.
                                                             (line    8)
* Common Vulnerabilities and Exposures; CVE 2024-4030 <2>: Security<13>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2025-4138: tarfile.
                                                             (line    8)
* Common Vulnerabilities and Exposures; CVE 2025-4138 <1>: Security<7>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2025-4330: tarfile.
                                                             (line   19)
* Common Vulnerabilities and Exposures; CVE 2025-4330 <1>: Security<7>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2025-4435: tarfile.
                                                             (line   24)
* Common Vulnerabilities and Exposures; CVE 2025-4517: os path<2>.
                                                             (line   10)
* Common Vulnerabilities and Exposures; CVE 2025-4517 <1>: Security<7>.
                                                             (line   11)
* Common Vulnerabilities and Exposures; CVE 2026-2297: Security.
                                                             (line   15)
* Common Vulnerabilities and Exposures; CVE 2026-3644: Security.
                                                             (line   13)
* Common Vulnerabilities and Exposures; CVE 2026-4224: Security.
                                                             (line    8)
* Common Weakness Enumeration; CWE 257:  Recipes and best practices.
                                                             (line   16)
* Common Weakness Enumeration; CWE 295:  ssl<2>.             (line   21)
* Common Weakness Enumeration; CWE 295 <1>: Library<63>.     (line  516)
* common_dirs (filecmp.dircmp attribute): The dircmp class.  (line   75)
* common_files (filecmp.dircmp attribute): The dircmp class. (line   79)
* common_funny (filecmp.dircmp attribute): The dircmp class. (line   83)
* common_types (in module mimetypes):    mimetypes — Map filenames to MIME types.
                                                             (line  157)
* commonpath() (in module os.path):      os path — Common pathname manipulations.
                                                             (line   73)
* commonprefix() (in module os.path):    os path — Common pathname manipulations.
                                                             (line   89)
* communicate() (asyncio.subprocess.Process method): Interacting with Subprocesses.
                                                             (line   50)
* communicate() (subprocess.Popen method): Popen Objects.    (line   36)
* Compare (class in ast):                Expressions<2>.     (line   91)
* compare_digest() (in module hmac):     hmac — Keyed-Hashing for Message Authentication.
                                                             (line  116)
* compare_digest() (in module secrets):  Other functions.    (line    6)
* compare_networks() (ipaddress.IPv4Network method): Network objects.
                                                             (line  237)
* compare_networks() (ipaddress.IPv6Network method): Network objects.
                                                             (line  352)
* COMPARE_OP (opcode):                   Python Bytecode Instructions.
                                                             (line  797)
* compare_signal() (decimal.Context method): Context objects.
                                                             (line  277)
* compare_signal() (decimal.Decimal method): Decimal objects.
                                                             (line  157)
* compare_to() (tracemalloc.Snapshot method): Snapshot.      (line   13)
* compare_total_mag() (decimal.Context method): Context objects.
                                                             (line  285)
* compare_total_mag() (decimal.Decimal method): Decimal objects.
                                                             (line  189)
* compare_total() (decimal.Context method): Context objects. (line  281)
* compare_total() (decimal.Decimal method): Decimal objects. (line  164)
* compare() (decimal.Context method):    Context objects.    (line  273)
* compare() (decimal.Decimal method):    Decimal objects.    (line  146)
* compare() (difflib.Differ method):     Differ objects.     (line   37)
* comparison:                            Comparisons.        (line    6)
* COMPARISON_FLAGS (in module doctest):  Option Flags.       (line  102)
* comparisons:                           Basic customization.
                                                             (line  185)
* Compat32 (class in email.policy):      email policy Policy Objects.
                                                             (line  562)
* compat32 (in module email.policy):     email policy Policy Objects.
                                                             (line  617)
* Compile (class in codeop):             codeop — Compile Python code.
                                                             (line   56)
* compile_command() (in module code):    code — Interpreter base classes.
                                                             (line   60)
* compile_command() (in module codeop):  codeop — Compile Python code.
                                                             (line   29)
* compile_dir() (in module compileall):  Public functions.   (line    6)
* compile_file() (in module compileall): Public functions.   (line   96)
* compile_path() (in module compileall): Public functions.   (line  161)
* compile() (in module py_compile):      py_compile — Compile Python source files.
                                                             (line   24)
* compile() (in module re):              Functions<2>.       (line    6)
* compileall command line option; -b:    Command-line use.   (line   66)
* compileall command line option; -d:    Command-line use.   (line   32)
* compileall command line option; -e:    Command-line use.   (line  107)
* compileall command line option; -f:    Command-line use.   (line   22)
* compileall command line option; -hardlink-dupes: Command-line use.
                                                             (line  111)
* compileall command line option; -i:    Command-line use.   (line   60)
* compileall command line option; -invalidation-mode: Command-line use.
                                                             (line   87)
* compileall command line option; -j:    Command-line use.   (line   81)
* compileall command line option; -l:    Command-line use.   (line   17)
* compileall command line option; -o:    Command-line use.   (line  101)
* compileall command line option; -p:    Command-line use.   (line   47)
* compileall command line option; -q:    Command-line use.   (line   26)
* compileall command line option; -r:    Command-line use.   (line   74)
* compileall command line option; -s:    Command-line use.   (line   40)
* compileall command line option; -x:    Command-line use.   (line   54)
* compileall command line option; directory: Command-line use.
                                                             (line    9)
* compileall command line option; file:  Command-line use.   (line    9)
* compiler_flag (__future__._Feature attribute): Module Contents<4>.
                                                             (line   88)
* complete_statement() (in module sqlite3): Module functions.
                                                             (line  104)
* complete() (rlcompleter.Completer method): rlcompleter — Completion function for GNU readline.
                                                             (line   43)
* completedefault() (cmd.Cmd method):    Cmd Objects.        (line   81)
* CompletedProcess (class in subprocess): Using the subprocess Module.
                                                             (line  100)
* Completer (class in rlcompleter):      rlcompleter — Completion function for GNU readline.
                                                             (line   39)
* complex (built-in class):              Built-in Functions. (line  365)
* Complex (class in numbers):            The numeric tower.  (line    6)
* complex literal:                       Numeric literals.   (line    6)
* complex number:                        Glossary.           (line  287)
* complex number; literals:              Numeric Types — int float complex.
                                                             (line   19)
* complex; number:                       numbers Complex complex.
                                                             (line    6)
* compound; statement:                   Compound statements.
                                                             (line    6)
* comprehension (class in ast):          Comprehensions.     (line   58)
* comprehensions:                        Displays for lists sets and dictionaries.
                                                             (line    6)
* compress_size (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  154)
* compress_type (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line   99)
* compress() (bz2.BZ2Compressor method): Incremental de compression.
                                                             (line   15)
* compress() (in module bz2):            One-shot de compression.
                                                             (line    6)
* compress() (in module gzip):           gzip — Support for gzip files.
                                                             (line  188)
* compress() (in module itertools):      Itertool Functions. (line  212)
* compress() (in module lzma):           Compressing and decompressing data in memory.
                                                             (line  181)
* compress() (in module zlib):           zlib — Compression compatible with gzip.
                                                             (line   43)
* compress() (lzma.LZMACompressor method): Compressing and decompressing data in memory.
                                                             (line   80)
* compress() (zlib.Compress method):     zlib — Compression compatible with gzip.
                                                             (line  202)
* compressed (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   58)
* compressed (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  107)
* compressed (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  251)
* compressed (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  319)
* compression() (ssl.SSLSocket method):  SSL sockets.        (line  249)
* CompressionError:                      tarfile — Read and write tar archive files.
                                                             (line  208)
* compressobj() (in module zlib):        zlib — Compression compatible with gzip.
                                                             (line   80)
* COMSPEC:                               Process Management. (line  770)
* COMSPEC <1>:                           Popen Constructor.  (line  112)
* concat() (in module operator):         operator — Standard operators as functions.
                                                             (line  176)
* Concatenate (in module typing):        Special forms.      (line   74)
* concatenation; operation:              Common Sequence Operations.
                                                             (line   21)
* concurrency:                           Glossary.           (line  300)
* concurrent modification:               Glossary.           (line  312)
* cond (bdb.Breakpoint attribute):       bdb — Debugger framework.
                                                             (line   94)
* Condition (class in asyncio):          Condition.          (line    6)
* Condition (class in multiprocessing):  Synchronization primitives.
                                                             (line   38)
* Condition (class in threading):        Condition objects.  (line   72)
* condition (pdb command):               Debugger commands.  (line  153)
* Condition() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  172)
* Conditional; expression:               Boolean operations. (line    6)
* conditional; expression:               Conditional expressions.
                                                             (line    6)
* config() (tkinter.font.Font method):   tkinter font — Tkinter font wrapper.
                                                             (line   55)
* ConfigParser (class in configparser):  ConfigParser Objects.
                                                             (line    6)
* configuration information:             sysconfig — Provide access to Python’s configuration information.
                                                             (line   10)
* configuration; file:                   configparser — Configuration file parser.
                                                             (line    8)
* configure_mock() (unittest.mock.Mock method): The Mock Class.
                                                             (line  263)
* configure() (tkinter.ttk.Style method): Ttk Styling.       (line   24)
* CONFORM (enum.FlagBoundary attribute): Data types.         (line  733)
* confstr_names (in module os):          Miscellaneous System Information.
                                                             (line   28)
* confstr() (in module os):              Miscellaneous System Information.
                                                             (line    6)
* conjugate() (complex number method):   Numeric Types — int float complex.
                                                             (line   94)
* conjugate() (decimal.Decimal method):  Decimal objects.    (line  201)
* conjugate() (numbers.Complex method):  The numeric tower.  (line   23)
* connect_accepted_socket() (asyncio.loop method): Creating network servers.
                                                             (line  145)
* connect_ex() (socket.socket method):   Socket Objects.     (line   85)
* connect_read_pipe() (asyncio.loop method): Working with pipes.
                                                             (line    6)
* connect_write_pipe() (asyncio.loop method): Working with pipes.
                                                             (line   22)
* connect() (ftplib.FTP method):         FTP objects.        (line   88)
* connect() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  148)
* connect() (in module sqlite3):         Module functions.   (line    6)
* connect() (multiprocessing.managers.BaseManager method): Managers.
                                                             (line   77)
* connect() (smtplib.SMTP method):       SMTP Objects.       (line   33)
* connect() (socket.socket method):      Socket Objects.     (line   61)
* Connection (class in multiprocessing.connection): Connection Objects.
                                                             (line   13)
* Connection (class in sqlite3):         Connection objects. (line    6)
* connection (sqlite3.Cursor attribute): Cursor objects.     (line  181)
* connection_lost() (asyncio.BaseProtocol method): Base Protocol.
                                                             (line   23)
* connection_made() (asyncio.BaseProtocol method): Base Protocol.
                                                             (line   15)
* ConnectionAbortedError:                OS exceptions.      (line   45)
* ConnectionError:                       OS exceptions.      (line   30)
* ConnectionRefusedError:                OS exceptions.      (line   51)
* ConnectionResetError:                  OS exceptions.      (line   57)
* ConnectRegistry() (in module winreg):  Functions<13>.      (line   17)
* const (optparse.Option attribute):     Option attributes.  (line   58)
* constant:                              Literals.           (line    6)
* Constant (class in ast):               Literals<3>.        (line    6)
* constructor() (in module copyreg):     copyreg — Register pickle support functions.
                                                             (line   17)
* consumed (asyncio.LimitOverrunError attribute): Exceptions<13>.
                                                             (line   66)
* container:                             Objects values and types.
                                                             (line   66)
* container <1>:                         Custom classes.     (line   19)
* Container (class in collections.abc):  Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line    6)
* Container (class in typing):           Aliases to container ABCs in collections abc.
                                                             (line   47)
* container; iteration over:             Iterator Types.     (line    6)
* CONTAINS_OP (opcode):                  Python Bytecode Instructions.
                                                             (line  812)
* contains() (in module operator):       operator — Standard operators as functions.
                                                             (line  181)
* content (urllib.error.ContentTooShortError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   70)
* content_disposition (email.headerregistry.ContentDispositionHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  284)
* content_manager (email.policy.EmailPolicy attribute): email policy Policy Objects.
                                                             (line  418)
* content_type (email.headerregistry.ContentTypeHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  271)
* ContentDispositionHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  279)
* ContentHandler (class in xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   18)
* ContentManager (class in email.contentmanager): email contentmanager Managing MIME Content.
                                                             (line   12)
* contents (ctypes._Pointer attribute):  Arrays and pointers.
                                                             (line   58)
* contents() (importlib.abc.ResourceReader method): importlib abc – Abstract base classes related to import.
                                                             (line  488)
* contents() (importlib.resources.abc.ResourceReader method): importlib resources abc – Abstract base classes for resources.
                                                             (line   71)
* contents() (in module importlib.resources): Functional API.
                                                             (line  150)
* ContentTooShortError:                  urllib error — Exception classes raised by urllib request.
                                                             (line   64)
* ContentTransferEncodingHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  289)
* ContentTypeHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  266)
* context:                               Glossary.           (line  319)
* Context (class in contextvars):        Manual Context Management.
                                                             (line   20)
* Context (class in decimal):            Context objects.    (line  115)
* context (ssl.SSLSocket attribute):     SSL sockets.        (line  342)
* context management protocol:           Context Manager Types.
                                                             (line    6)
* context management protocol <1>:       Glossary.           (line  336)
* context manager:                       With Statement Context Managers.
                                                             (line   14)
* context manager <1>:                   Context Manager Types.
                                                             (line    6)
* context manager <2>:                   Glossary.           (line  340)
* context variable:                      Glossary.           (line  346)
* context_diff() (in module difflib):    difflib — Helpers for computing deltas.
                                                             (line  154)
* ContextDecorator (class in contextlib): Utilities.         (line  380)
* ContextManager (class in typing):      Aliases to contextlib ABCs.
                                                             (line    6)
* contextmanager() (in module contextlib): Utilities.        (line   30)
* ContextVar (class in contextvars):     Context Variables.  (line    6)
* CONTIG (inspect.BufferFlags attribute): Buffer flags.      (line   33)
* CONTIG_RO (inspect.BufferFlags attribute): Buffer flags.   (line   35)
* contiguous:                            shape strides suboffsets.
                                                             (line   34)
* contiguous <1>:                        Glossary.           (line  354)
* contiguous (memoryview attribute):     Memory Views.       (line  490)
* Continue (class in ast):               Control flow.       (line   99)
* continue (pdb command):                Debugger commands.  (line  225)
* CONTINUOUS (enum.EnumCheck attribute): Data types.         (line  672)
* control() (select.kqueue method):      Kqueue Objects.     (line   22)
* controlnames (in module curses.ascii): curses ascii — Utilities for ASCII characters.
                                                             (line  239)
* CONTTYPE (in module tarfile):          tarfile — Read and write tar archive files.
                                                             (line  306)
* convert_arg_line_to_args() (argparse.ArgumentParser method): Customizing file parsing.
                                                             (line    6)
* convert_field() (string.Formatter method): Custom string formatting.
                                                             (line  107)
* CONVERT_VALUE (opcode):                Python Bytecode Instructions.
                                                             (line 1168)
* Cookie (class in http.cookiejar):      http cookiejar — Cookie handling for HTTP clients.
                                                             (line  111)
* CookieError:                           http cookies — HTTP state management.
                                                             (line   33)
* CookieJar (class in http.cookiejar):   http cookiejar — Cookie handling for HTTP clients.
                                                             (line   45)
* cookiejar (urllib.request.HTTPCookieProcessor attribute): HTTPCookieProcessor Objects.
                                                             (line    8)
* CookiePolicy (class in http.cookiejar): http cookiejar — Cookie handling for HTTP clients.
                                                             (line   76)
* Coordinated Universal Time:            time — Time access and conversions.
                                                             (line   39)
* Copy:                                  Help menu Shell and Editor.
                                                             (line   30)
* COPY (opcode):                         Python Bytecode Instructions.
                                                             (line  159)
* copy_abs() (decimal.Context method):   Context objects.    (line  290)
* copy_abs() (decimal.Decimal method):   Decimal objects.    (line  206)
* copy_context() (in module contextvars): Manual Context Management.
                                                             (line    6)
* copy_decimal() (decimal.Context method): Context objects.  (line  197)
* copy_file_range() (in module os):      File Descriptor Operations.
                                                             (line   44)
* COPY_FREE_VARS (opcode):               Python Bytecode Instructions.
                                                             (line 1015)
* copy_location() (in module ast):       ast Helpers.        (line  161)
* copy_negate() (decimal.Context method): Context objects.   (line  294)
* copy_negate() (decimal.Decimal method): Decimal objects.   (line  212)
* copy_sign() (decimal.Context method):  Context objects.    (line  298)
* copy_sign() (decimal.Decimal method):  Decimal objects.    (line  218)
* copy; protocol:                        Pickling Class Instances.
                                                             (line  111)
* copy() (collections.deque method):     deque objects.      (line   47)
* copy() (contextvars.Context method):   Manual Context Management.
                                                             (line  103)
* copy() (decimal.Context method):       Context objects.    (line  193)
* copy() (dict method):                  Mapping Types — dict.
                                                             (line  165)
* copy() (frozenset method):             Set Types — set frozenset.
                                                             (line  128)
* copy() (hashlib.hash method):          Hash Objects.       (line   51)
* copy() (hmac.HMAC method):             hmac — Keyed-Hashing for Message Authentication.
                                                             (line   86)
* copy() (http.cookies.Morsel method):   Morsel Objects.     (line   99)
* copy() (imaplib.IMAP4 method):         IMAP4 Objects.      (line   68)
* copy() (in module copy):               copy — Shallow and deep copy operations.
                                                             (line   18)
* copy() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   91)
* copy() (in module shutil):             Directory and files operations.
                                                             (line  128)
* copy() (sequence method):              Mutable Sequence Types.
                                                             (line   81)
* copy() (set method):                   Set Types — set frozenset.
                                                             (line  128)
* copy() (tkinter.font.Font method):     tkinter font — Tkinter font wrapper.
                                                             (line   59)
* copy() (types.MappingProxyType method): Standard Interpreter Types.
                                                             (line  256)
* copy() (zlib.Compress method):         zlib — Compression compatible with gzip.
                                                             (line  224)
* copy() (zlib.Decompress method):       zlib — Compression compatible with gzip.
                                                             (line  292)
* copy2() (in module shutil):            Directory and files operations.
                                                             (line  160)
* copyfile() (in module shutil):         Directory and files operations.
                                                             (line   17)
* copyfileobj() (in module shutil):      Directory and files operations.
                                                             (line    6)
* copying files:                         shutil — High-level file operations.
                                                             (line    8)
* copymode() (in module shutil):         Directory and files operations.
                                                             (line   66)
* copyright (built-in variable):         Constants added by the site module.
                                                             (line   26)
* copyright (in module sys):             sys — System-specific parameters and functions.
                                                             (line  177)
* copyright (in module sys) <1>:         Process-wide parameters.
                                                             (line  190)
* copysign() (in module math):           Floating point manipulation functions.
                                                             (line    6)
* copystat() (in module shutil):         Directory and files operations.
                                                             (line   84)
* copytree() (in module shutil):         Directory and files operations.
                                                             (line  198)
* coroutine:                             Special method lookup.
                                                             (line   74)
* coroutine <1>:                         Yield expressions.  (line   54)
* coroutine <2>:                         Glossary.           (line  365)
* Coroutine (class in collections.abc):  Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  149)
* Coroutine (class in typing):           Aliases to asynchronous ABCs in collections abc.
                                                             (line    6)
* coroutine function:                    Glossary.           (line  373)
* coroutine; function:                   Coroutine functions.
                                                             (line    6)
* coroutine() (in module types):         Coroutine Utility Functions.
                                                             (line    6)
* CoroutineType (in module types):       Standard Interpreter Types.
                                                             (line   42)
* correlation() (in module statistics):  Function details.   (line  580)
* cos() (in module cmath):               Trigonometric functions<2>.
                                                             (line   23)
* cos() (in module math):                Trigonometric functions.
                                                             (line   30)
* cosh() (in module cmath):              Hyperbolic functions<2>.
                                                             (line   23)
* cosh() (in module math):               Hyperbolic functions.
                                                             (line   21)
* count (tracemalloc.Statistic attribute): Statistic.        (line   15)
* count (tracemalloc.StatisticDiff attribute): StatisticDiff.
                                                             (line   15)
* count_diff (tracemalloc.StatisticDiff attribute): StatisticDiff.
                                                             (line   20)
* count() (array.array method):          array — Efficient arrays of numeric values.
                                                             (line  155)
* count() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line   36)
* count() (bytes method):                Bytes and Bytearray Operations.
                                                             (line   36)
* count() (collections.deque method):    deque objects.      (line   53)
* count() (in module itertools):         Itertool Functions. (line  225)
* count() (multiprocessing.shared_memory.ShareableList method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  332)
* count() (sequence method):             Common Sequence Operations.
                                                             (line  172)
* count() (str method):                  String Methods<2>.  (line   67)
* Counter (class in collections):        Counter objects.    (line   24)
* Counter (class in typing):             Aliases to types in collections.
                                                             (line   39)
* countOf() (in module operator):        operator — Standard operators as functions.
                                                             (line  187)
* countTestCases() (unittest.TestCase method): Test cases.   (line  732)
* countTestCases() (unittest.TestSuite method): Grouping tests.
                                                             (line   53)
* covariance() (in module statistics):   Function details.   (line  558)
* CoverageResults (class in trace):      Programmatic Interface.
                                                             (line   47)
* CPPFLAGS:                              New Improved and Deprecated Modules<4>.
                                                             (line   59)
* CPPFLAGS <1>:                          Preprocessor flags. (line    8)
* CPPFLAGS <2>:                          Preprocessor flags. (line   18)
* CPPFLAGS <3>:                          Linker flags.       (line   50)
* cProfile command line option; -m:      Instant User’s Manual.
                                                             (line   99)
* cProfile command line option; -o:      Instant User’s Manual.
                                                             (line   89)
* cProfile command line option; -s:      Instant User’s Manual.
                                                             (line   93)
* CPU time:                              Functions<5>.       (line  247)
* CPU time <1>:                          Functions<5>.       (line  615)
* cpu_count() (in module multiprocessing): Miscellaneous<3>. (line   13)
* cpu_count() (in module os):            Miscellaneous System Information.
                                                             (line   37)
* CPython:                               Glossary.           (line  381)
* cpython_only() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  532)
* CR (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   63)
* crawl_delay() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   50)
* CRC (zipfile.ZipInfo attribute):       ZipInfo objects.    (line  150)
* crc_hqx() (in module binascii):        binascii — Convert between binary and ASCII.
                                                             (line   91)
* crc32() (in module binascii):          binascii — Convert between binary and ASCII.
                                                             (line   98)
* crc32() (in module zlib):              zlib — Compression compatible with gzip.
                                                             (line  120)
* create_aggregate() (sqlite3.Connection method): Connection objects.
                                                             (line  157)
* create_archive() (in module zipapp):   Python API.         (line    8)
* create_autospec() (in module unittest.mock): create_autospec.
                                                             (line    6)
* CREATE_BREAKAWAY_FROM_JOB (in module subprocess): Windows Constants.
                                                             (line  140)
* create_collation() (sqlite3.Connection method): Connection objects.
                                                             (line  301)
* create_configuration() (venv.EnvBuilder method): API<2>.   (line  148)
* create_connection() (asyncio.loop method): Opening network connections.
                                                             (line    6)
* create_connection() (in module socket): Creating sockets.  (line   82)
* create_datagram_endpoint() (asyncio.loop method): Opening network connections.
                                                             (line  157)
* create_decimal_from_float() (decimal.Context method): Context objects.
                                                             (line  225)
* create_decimal() (decimal.Context method): Context objects.
                                                             (line  201)
* create_default_context() (in module ssl): Context creation.
                                                             (line    9)
* CREATE_DEFAULT_ERROR_MODE (in module subprocess): Windows Constants.
                                                             (line  130)
* create_eager_task_factory() (in module asyncio): Eager task factory.
                                                             (line   32)
* create_empty_file() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   91)
* create_function() (sqlite3.Connection method): Connection objects.
                                                             (line  115)
* create_future() (asyncio.loop method): Creating futures and tasks.
                                                             (line    6)
* create_git_ignore_file() (venv.EnvBuilder method): API<2>. (line  215)
* create_module() (importlib.abc.Loader method): importlib abc – Abstract base classes related to import.
                                                             (line  102)
* create_module() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  314)
* create_module() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   23)
* CREATE_NEW_CONSOLE (in module subprocess): Windows Constants.
                                                             (line   54)
* CREATE_NEW_PROCESS_GROUP (in module subprocess): Windows Constants.
                                                             (line   59)
* CREATE_NO_WINDOW (in module subprocess): Windows Constants.
                                                             (line  115)
* create_server() (asyncio.loop method): Creating network servers.
                                                             (line    6)
* create_server() (in module socket):    Creating sockets.   (line  113)
* create_stats() (profile.Profile method): profile and cProfile Module Reference.
                                                             (line   86)
* create_string_buffer() (in module ctypes): Utility functions.
                                                             (line   40)
* create_subprocess_exec() (in module asyncio): Creating Subprocesses.
                                                             (line    6)
* create_subprocess_shell() (in module asyncio): Creating Subprocesses.
                                                             (line   26)
* create_system (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  114)
* create_task() (asyncio.loop method):   Creating futures and tasks.
                                                             (line   17)
* create_task() (asyncio.TaskGroup method): Task groups.     (line   17)
* create_task() (in module asyncio):     Creating tasks.     (line   10)
* create_unicode_buffer() (in module ctypes): Utility functions.
                                                             (line   81)
* create_unix_connection() (asyncio.loop method): Opening network connections.
                                                             (line  242)
* create_unix_server() (asyncio.loop method): Creating network servers.
                                                             (line  115)
* create_version (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  118)
* create_window_function() (sqlite3.Connection method): Connection objects.
                                                             (line  212)
* create() (imaplib.IMAP4 method):       IMAP4 Objects.      (line   72)
* create() (in module venv):             API<2>.             (line  235)
* create() (venv.EnvBuilder method):     API<2>.             (line   62)
* createAttribute() (xml.dom.Document method): Document Objects.
                                                             (line   46)
* createAttributeNS() (xml.dom.Document method): Document Objects.
                                                             (line   53)
* createComment() (xml.dom.Document method): Document Objects.
                                                             (line   34)
* createDocument() (xml.dom.DOMImplementation method): DOMImplementation Objects.
                                                             (line   16)
* createDocumentType() (xml.dom.DOMImplementation method): DOMImplementation Objects.
                                                             (line   26)
* createElement() (xml.dom.Document method): Document Objects.
                                                             (line   14)
* createElementNS() (xml.dom.Document method): Document Objects.
                                                             (line   21)
* createfilehandler() (_tkinter.Widget.tk method): File Handlers.
                                                             (line   27)
* CreateKey() (in module winreg):        Functions<13>.      (line   35)
* CreateKeyEx() (in module winreg):      Functions<13>.      (line   63)
* createLock() (logging.Handler method): Handler Objects.    (line   20)
* createLock() (logging.NullHandler method): NullHandler.    (line   24)
* createProcessingInstruction() (xml.dom.Document method): Document Objects.
                                                             (line   40)
* createSocket() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   72)
* createSocket() (logging.handlers.SysLogHandler method): SysLogHandler.
                                                             (line   50)
* createTextNode() (xml.dom.Document method): Document Objects.
                                                             (line   28)
* credits (built-in variable):           Constants added by the site module.
                                                             (line   26)
* CRITICAL (in module logging):          Logging Levels.     (line   45)
* critical() (in module logging):        Module-Level Functions.
                                                             (line   86)
* critical() (logging.Logger method):    Logger Objects.     (line  307)
* CRNCYSTR (in module locale):           locale — Internationalization services.
                                                             (line  305)
* CRT_ASSEMBLY_VERSION (in module msvcrt): Other Functions.  (line   89)
* CRT_ASSERT (in module msvcrt):         Other Functions.    (line   66)
* CRT_ERROR (in module msvcrt):          Other Functions.    (line   61)
* CRT_WARN (in module msvcrt):           Other Functions.    (line   56)
* CRTDBG_MODE_DEBUG (in module msvcrt):  Other Functions.    (line   70)
* CRTDBG_MODE_FILE (in module msvcrt):   Other Functions.    (line   74)
* CRTDBG_MODE_WNDW (in module msvcrt):   Other Functions.    (line   80)
* CRTDBG_REPORT_MODE (in module msvcrt): Other Functions.    (line   85)
* CrtSetReportFile() (in module msvcrt): Other Functions.    (line   48)
* CrtSetReportMode() (in module msvcrt): Other Functions.    (line   40)
* cryptography:                          Cryptographic Services.
                                                             (line    6)
* cssclass_month (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  292)
* cssclass_month_head (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  285)
* cssclass_noday (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  271)
* cssclass_year (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  299)
* cssclass_year_head (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  306)
* cssclasses (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  258)
* cssclasses_weekday_head (calendar.HTMLCalendar attribute): calendar — General calendar-related functions.
                                                             (line  278)
* csv:                                   csv — CSV File Reading and Writing.
                                                             (line    8)
* cte (email.headerregistry.ContentTransferEncodingHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  293)
* cte_type (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  160)
* ctermid() (in module os):              Process Parameters. (line    9)
* ctime() (datetime.date method):        date Objects.       (line  284)
* ctime() (datetime.datetime method):    datetime Objects.   (line  734)
* ctime() (in module time):              Functions<5>.       (line   93)
* CTRL_BREAK_EVENT (in module signal):   Module contents<3>. (line  230)
* CTRL_C_EVENT (in module signal):       Module contents<3>. (line  221)
* ctrl() (in module curses.ascii):       curses ascii — Utilities for ASCII characters.
                                                             (line  215)
* curdir (in module os):                 Miscellaneous System Information.
                                                             (line  103)
* currency() (in module locale):         locale — Internationalization services.
                                                             (line  478)
* current context:                       Glossary.           (line  388)
* current_process() (in module multiprocessing): Miscellaneous<3>.
                                                             (line   35)
* current_task() (in module asyncio):    Introspection.      (line    6)
* current_thread() (in module threading): Reference<2>.      (line   16)
* current() (tkinter.ttk.Combobox method): ttk Combobox.     (line    8)
* CurrentByteIndex (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  244)
* CurrentColumnNumber (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  248)
* currentframe() (in module inspect):    The interpreter stack.
                                                             (line  161)
* CurrentLineNumber (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  252)
* curs_set() (in module curses):         Functions<6>.       (line   61)
* Cursor (class in sqlite3):             Cursor objects.     (line   19)
* cursor() (sqlite3.Connection method):  Connection objects. (line   27)
* cursyncup() (curses.window method):    Window Objects.     (line  174)
* Cut:                                   Help menu Shell and Editor.
                                                             (line   30)
* cutoff (sys.hash_info attribute):      sys — System-specific parameters and functions.
                                                             (line 1066)
* cwd() (ftplib.FTP method):             FTP objects.        (line  335)
* cwd() (pathlib.Path class method):     Expanding and resolving paths.
                                                             (line   30)
* cycle() (in module itertools):         Itertool Functions. (line  247)
* CycleError:                            Exceptions<4>.      (line    8)
* Cyclic Redundancy Check:               zlib — Compression compatible with gzip.
                                                             (line  122)
* D_FMT (in module locale):              locale — Internationalization services.
                                                             (line  208)
* D_T_FMT (in module locale):            locale — Internationalization services.
                                                             (line  202)
* daemon (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  134)
* daemon (threading.Thread attribute):   Thread objects.     (line  200)
* daemon_threads (socketserver.ThreadingMixIn attribute): Server Creation Notes.
                                                             (line   54)
* dangling; else:                        Compound statements.
                                                             (line   55)
* data:                                  Objects values and types.
                                                             (line    6)
* data (collections.UserDict attribute): UserDict objects.   (line   27)
* data (collections.UserList attribute): UserList objects.   (line   28)
* data (collections.UserString attribute): UserString objects.
                                                             (line   24)
* data (plistlib.UID attribute):         plistlib — Generate and parse Apple plist files.
                                                             (line  147)
* data (select.kevent attribute):        Kevent Objects.     (line  175)
* data (selectors.SelectorKey attribute): Classes<4>.        (line   48)
* data (urllib.request.Request attribute): Request Objects.  (line   39)
* data (xml.dom.Comment attribute):      Comment Objects.    (line    9)
* data (xml.dom.ProcessingInstruction attribute): ProcessingInstruction Objects.
                                                             (line   14)
* data (xml.dom.Text attribute):         Text and CDATASection Objects.
                                                             (line   15)
* data (xmlrpc.client.Binary attribute): Binary Objects.     (line   12)
* data race:                             Glossary.           (line  398)
* data_filter() (in module tarfile):     Default named filters.
                                                             (line   36)
* data_open() (urllib.request.DataHandler method): DataHandler Objects.
                                                             (line    6)
* data_received() (asyncio.Protocol method): Streaming Protocols.
                                                             (line   13)
* data; tabular:                         csv — CSV File Reading and Writing.
                                                             (line    8)
* data; type:                            The standard type hierarchy.
                                                             (line    6)
* data() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   33)
* DatabaseError:                         Exceptions<7>.      (line   44)
* databases:                             dbm dumb — Portable DBM implementation.
                                                             (line    8)
* dataclass_transform() (in module typing): Functions and decorators.
                                                             (line  114)
* dataclass() (in module dataclasses):   Module contents<5>. (line    6)
* DataError:                             Exceptions<7>.      (line   51)
* datagram_received() (asyncio.DatagramProtocol method): Datagram Protocols.
                                                             (line    9)
* DatagramHandler (class in logging.handlers): DatagramHandler.
                                                             (line   10)
* DatagramProtocol (class in asyncio):   Base Protocols.     (line   20)
* DatagramRequestHandler (class in socketserver): Request Handler Objects.
                                                             (line   56)
* DatagramTransport (class in asyncio):  Transports Hierarchy.
                                                             (line   43)
* DataHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  426)
* date (class in datetime):              date Objects.       (line   13)
* date_time (zipfile.ZipInfo attribute): ZipInfo objects.    (line   55)
* date_time_string() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  322)
* date() (datetime.datetime method):     datetime Objects.   (line  440)
* DateHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  136)
* datetime (class in datetime):          datetime Objects.   (line   17)
* DateTime (class in xmlrpc.client):     DateTime Objects.   (line    6)
* datetime (email.headerregistry.DateHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  145)
* Day (class in calendar):               calendar — General calendar-related functions.
                                                             (line  458)
* day (datetime.date attribute):         date Objects.       (line  124)
* day (datetime.datetime attribute):     datetime Objects.   (line  312)
* DAY_1 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_2 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_3 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_4 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_5 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_6 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* DAY_7 (in module locale):              locale — Internationalization services.
                                                             (line  225)
* day_abbr (in module calendar):         calendar — General calendar-related functions.
                                                             (line  436)
* day_name (in module calendar):         calendar — General calendar-related functions.
                                                             (line  427)
* daylight (in module time):             Timezone Constants. (line   13)
* Daylight Saving Time:                  time — Time access and conversions.
                                                             (line   45)
* days (datetime.timedelta attribute):   timedelta Objects.  (line  115)
* DbfilenameShelf (class in shelve):     Restrictions.       (line   73)
* DC1 (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   75)
* DC2 (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   78)
* DC3 (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   81)
* DC4 (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   84)
* dcgettext() (in module locale):        Access to message catalogs.
                                                             (line   10)
* deactivate_stack_trampoline() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1764)
* deadlock:                              Glossary.           (line  410)
* deallocation, object:                  Finalization and De-allocation.
                                                             (line    6)
* debug (imaplib.IMAP4 attribute):       IMAP4 Objects.      (line  400)
* DEBUG (in module logging):             Logging Levels.     (line   24)
* DEBUG (in module re):                  Flags.              (line   32)
* debug (pdb command):                   Debugger commands.  (line  428)
* debug (shlex.shlex attribute):         shlex Objects.      (line  162)
* debug (sys.flags attribute):           sys — System-specific parameters and functions.
                                                             (line  527)
* debug (zipfile.ZipFile attribute):     ZipFile objects.    (line  353)
* DEBUG_BYTECODE_SUFFIXES (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   20)
* DEBUG_COLLECTABLE (in module gc):      gc — Garbage Collector interface.
                                                             (line  301)
* DEBUG_LEAK (in module gc):             gc — Garbage Collector interface.
                                                             (line  321)
* DEBUG_SAVEALL (in module gc):          gc — Garbage Collector interface.
                                                             (line  315)
* debug_src() (in module doctest):       Debugging.          (line  147)
* DEBUG_STATS (in module gc):            gc — Garbage Collector interface.
                                                             (line  296)
* DEBUG_UNCOLLECTABLE (in module gc):    gc — Garbage Collector interface.
                                                             (line  305)
* debug() (in module doctest):           Debugging.          (line  124)
* debug() (in module logging):           Module-Level Functions.
                                                             (line   46)
* debug() (logging.Logger method):       Logger Objects.     (line  186)
* debug() (unittest.TestCase method):    Test cases.         (line  118)
* debug() (unittest.TestSuite method):   Grouping tests.     (line   46)
* debugger:                              Reference<2>.       (line  132)
* debugger <1>:                          Debug menu Shell window only.
                                                             (line   15)
* debugger <2>:                          sys — System-specific parameters and functions.
                                                             (line  942)
* debugger <3>:                          sys — System-specific parameters and functions.
                                                             (line 1604)
* debugger; configuration; file:         Debugger commands.  (line   59)
* debugging:                             pdb — The Python Debugger.
                                                             (line    8)
* debugging; assertions:                 The assert statement.
                                                             (line    6)
* debuglevel (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   69)
* DebugRunner (class in doctest):        Debugging.          (line  168)
* DECEMBER (in module calendar):         calendar — General calendar-related functions.
                                                             (line  488)
* Decimal (class in decimal):            Decimal objects.    (line    6)
* decimal literal:                       Numeric literals.   (line    6)
* decimal() (in module unicodedata):     unicodedata — Unicode Database.
                                                             (line   51)
* DecimalException (class in decimal):   Signals.            (line   29)
* decode (codecs.CodecInfo attribute):   codecs — Codec registry and base classes.
                                                             (line   78)
* decode_header() (in module email.header): email header Internationalized headers.
                                                             (line  181)
* decode_params() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  215)
* decode_rfc2231() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  186)
* decode_source() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line   72)
* decode() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line   92)
* decode() (bytes method):               Bytes and Bytearray Operations.
                                                             (line   92)
* decode() (codecs.Codec method):        Stateless Encoding and Decoding.
                                                             (line   29)
* decode() (codecs.IncrementalDecoder method): IncrementalDecoder Objects.
                                                             (line   28)
* decode() (in module base64):           Legacy Interface.   (line    6)
* decode() (in module codecs):           codecs — Codec registry and base classes.
                                                             (line   34)
* decode() (in module quopri):           quopri — Encode and decode MIME quoted-printable data.
                                                             (line   19)
* decode() (json.JSONDecoder method):    Encoders and Decoders.
                                                             (line   87)
* decode() (xmlrpc.client.Binary method): Binary Objects.    (line   20)
* decode() (xmlrpc.client.DateTime method): DateTime Objects.
                                                             (line   13)
* decodebytes() (in module base64):      Legacy Interface.   (line   13)
* DecodedGenerator (class in email.generator): email generator Generating MIME documents.
                                                             (line  228)
* decodestring() (in module quopri):     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   41)
* decomposition() (in module unicodedata): unicodedata — Unicode Database.
                                                             (line  124)
* decompress() (bz2.BZ2Decompressor method): Incremental de compression.
                                                             (line   45)
* decompress() (in module bz2):          One-shot de compression.
                                                             (line   16)
* decompress() (in module gzip):         gzip — Support for gzip files.
                                                             (line  210)
* decompress() (in module lzma):         Compressing and decompressing data in memory.
                                                             (line  190)
* decompress() (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  134)
* decompress() (lzma.LZMADecompressor method): Compressing and decompressing data in memory.
                                                             (line  130)
* decompress() (zlib.Decompress method): zlib — Compression compatible with gzip.
                                                             (line  262)
* decompressobj() (in module zlib):      zlib — Compression compatible with gzip.
                                                             (line  179)
* decorator:                             Glossary.           (line  423)
* DEDENT (in module token):              token — Constants used with Python parse trees.
                                                             (line   91)
* DEDENT token:                          Indentation.        (line   33)
* DEDENT token <1>:                      Compound statements.
                                                             (line   55)
* dedent() (in module textwrap):         textwrap — Text wrapping and filling.
                                                             (line   76)
* deepcopy() (in module copy):           copy — Shallow and deep copy operations.
                                                             (line   22)
* DEF_BUF_SIZE (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  318)
* DEF_MEM_LEVEL (in module zlib):        zlib — Compression compatible with gzip.
                                                             (line  314)
* def_prog_mode() (in module curses):    Functions<6>.       (line   70)
* def_shell_mode() (in module curses):   Functions<6>.       (line   77)
* default (in module email.policy):      email policy Policy Objects.
                                                             (line  503)
* DEFAULT (in module unittest.mock):     DEFAULT.            (line    6)
* default (inspect.Parameter attribute): Introspecting callables with the Signature object.
                                                             (line  215)
* default (optparse.Option attribute):   Option attributes.  (line   44)
* DEFAULT_BUFFER_SIZE (in module io):    High-level Module Interface.
                                                             (line    6)
* default_bufsize (in module xml.dom.pulldom): xml dom pulldom — Support for building partial DOM trees.
                                                             (line  102)
* DEFAULT_ENTROPY (in module secrets):   How many bytes should tokens use?.
                                                             (line   21)
* default_exception_handler() (asyncio.loop method): Error handling API.
                                                             (line   34)
* default_factory (collections.defaultdict attribute): defaultdict objects.
                                                             (line   54)
* DEFAULT_FORMAT (in module tarfile):    tarfile — Read and write tar archive files.
                                                             (line  338)
* DEFAULT_IGNORES (in module filecmp):   The dircmp class.   (line  114)
* default_loader() (in module xml.etree.ElementInclude): Functions<10>.
                                                             (line    6)
* default_max_str_digits (sys.int_info attribute): sys — System-specific parameters and functions.
                                                             (line 1156)
* default_open() (urllib.request.BaseHandler method): BaseHandler Objects.
                                                             (line   30)
* DEFAULT_PROTOCOL (in module pickle):   Module Interface.   (line   21)
* DEFAULT_TIMEOUT (unittest.mock.ThreadingMock attribute): The Mock Class.
                                                             (line  995)
* default_timer() (in module timeit):    Python Interface.   (line   32)
* default; parameter; value:             Function definitions.
                                                             (line   68)
* default() (cmd.Cmd method):            Cmd Objects.        (line   75)
* default() (json.JSONEncoder method):   Encoders and Decoders.
                                                             (line  202)
* DefaultContext (in module decimal):    Context objects.    (line   90)
* DefaultCookiePolicy (class in http.cookiejar): http cookiejar — Cookie handling for HTTP clients.
                                                             (line   81)
* defaultdict (class in collections):    defaultdict objects.
                                                             (line    6)
* DefaultDict (class in typing):         Aliases to types in collections.
                                                             (line    6)
* DefaultEventLoopPolicy (class in asyncio): Policy Objects. (line   54)
* DefaultHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  400)
* DefaultHandlerExpand() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  407)
* defaults() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  112)
* DefaultSelector (class in selectors):  Classes<4>.         (line  161)
* defaultTestLoader (in module unittest): Loading and running tests.
                                                             (line  454)
* defaultTestResult() (unittest.TestCase method): Test cases.
                                                             (line  737)
* defects (email.headerregistry.BaseHeader attribute): email headerregistry Custom Header Objects.
                                                             (line   52)
* defects (email.message.EmailMessage attribute): email message Representing an email message.
                                                             (line  711)
* defects (email.message.Message attribute): email message Message Representing an email message using the compat32 API.
                                                             (line  725)
* DEFLATED (in module zlib):             zlib — Compression compatible with gzip.
                                                             (line  305)
* defpath (in module os):                Miscellaneous System Information.
                                                             (line  143)
* DefragResult (class in urllib.parse):  Structured Parse Results.
                                                             (line   40)
* DefragResultBytes (class in urllib.parse): Structured Parse Results.
                                                             (line   65)
* degrees() (in module math):            Angular conversion. (line    6)
* degrees() (in module turtle):          Settings for measurement.
                                                             (line    6)
* Del (class in ast):                    Variables.          (line   11)
* DEL (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line  123)
* del_param() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  383)
* del_param() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  543)
* delay_output() (in module curses):     Functions<6>.       (line   85)
* delay() (in module turtle):            Animation control.  (line    6)
* delayload (http.cookiejar.FileCookieJar attribute): CookieJar and FileCookieJar Objects.
                                                             (line  158)
* delch() (curses.window method):        Window Objects.     (line  179)
* dele() (poplib.POP3 method):           POP3 Objects.       (line   68)
* Delete (class in ast):                 Statements.         (line  138)
* DELETE_ATTR (opcode):                  Python Bytecode Instructions.
                                                             (line  615)
* DELETE_DEREF (opcode):                 Python Bytecode Instructions.
                                                             (line 1005)
* DELETE_FAST (opcode):                  Python Bytecode Instructions.
                                                             (line  966)
* DELETE_GLOBAL (opcode):                Python Bytecode Instructions.
                                                             (line  629)
* DELETE_NAME (opcode):                  Python Bytecode Instructions.
                                                             (line  569)
* DELETE_SUBSCR (opcode):                Python Bytecode Instructions.
                                                             (line  270)
* delete() (ftplib.FTP method):          FTP objects.        (line  328)
* delete() (imaplib.IMAP4 method):       IMAP4 Objects.      (line   76)
* delete() (tkinter.ttk.Treeview method): ttk Treeview.      (line   73)
* deleteacl() (imaplib.IMAP4 method):    IMAP4 Objects.      (line   80)
* deletefilehandler() (_tkinter.Widget.tk method): File Handlers.
                                                             (line   37)
* DeleteKey() (in module winreg):        Functions<13>.      (line  102)
* DeleteKeyEx() (in module winreg):      Functions<13>.      (line  124)
* deleteln() (curses.window method):     Window Objects.     (line  183)
* deleteMe() (bdb.Breakpoint method):    bdb — Debugger framework.
                                                             (line   42)
* DeleteValue() (in module winreg):      Functions<13>.      (line  160)
* deletion; target:                      The del statement<2>.
                                                             (line    6)
* deletion; target; list:                The del statement<2>.
                                                             (line    6)
* delimiter (csv.Dialect attribute):     Dialects and Formatting Parameters.
                                                             (line   18)
* delimiters:                            Delimiters.         (line    6)
* delitem() (in module operator):        operator — Standard operators as functions.
                                                             (line  191)
* deliver_challenge() (in module multiprocessing.connection): Listeners and Clients.
                                                             (line   15)
* delocalize() (in module locale):       locale — Internationalization services.
                                                             (line  499)
* demo_app() (in module wsgiref.simple_server): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   36)
* denominator (fractions.Fraction attribute): fractions — Rational numbers.
                                                             (line  115)
* denominator (numbers.Rational attribute): The numeric tower.
                                                             (line   55)
* deprecated() (in module warnings):     Available Functions.
                                                             (line  141)
* DeprecationWarning:                    Warnings.           (line   17)
* deque (class in collections):          deque objects.      (line    6)
* Deque (class in typing):               Aliases to types in collections.
                                                             (line   49)
* dequeue() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   49)
* DER_cert_to_PEM_cert() (in module ssl): Certificate handling.
                                                             (line   52)
* derive() (BaseExceptionGroup method):  Exception groups.   (line   79)
* derwin() (curses.window method):       Window Objects.     (line  188)
* descrgetfunc (C type):                 Slot Type typedefs. (line   69)
* description (inspect.Parameter.kind attribute): Introspecting callables with the Signature object.
                                                             (line  281)
* description (sqlite3.Cursor attribute): Cursor objects.    (line  194)
* descriptor:                            Glossary.           (line  445)
* descrsetfunc (C type):                 Slot Type typedefs. (line   74)
* deserialize() (sqlite3.Connection method): Connection objects.
                                                             (line  697)
* dest (optparse.Option attribute):      Option attributes.  (line   35)
* destructor:                            Basic customization.
                                                             (line   54)
* destructor <1>:                        Assignment statements.
                                                             (line   71)
* destructor (C type):                   Slot Type typedefs. (line   24)
* detach() (io.BufferedIOBase method):   I/O Base Classes.   (line  256)
* detach() (io.TextIOBase method):       Text I/O<2>.        (line   37)
* detach() (socket.socket method):       Socket Objects.     (line   99)
* detach() (tkinter.ttk.Treeview method): ttk Treeview.      (line   79)
* detach() (weakref.finalize method):    weakref — Weak references.
                                                             (line  299)
* Detach() (winreg.PyHKEY method):       Registry Handle Objects.
                                                             (line   36)
* DETACHED_PROCESS (in module subprocess): Windows Constants.
                                                             (line  122)
* detect_api_mismatch() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  642)
* detect_encoding() (in module tokenize): Tokenizing Input.  (line   73)
* deterministic profiling:               Introduction to the profilers.
                                                             (line    6)
* dev_mode (sys.flags attribute):        sys — System-specific parameters and functions.
                                                             (line  566)
* device_encoding() (in module os):      File Descriptor Operations.
                                                             (line   81)
* devmajor (tarfile.TarInfo attribute):  TarInfo Objects.    (line  141)
* devminor (tarfile.TarInfo attribute):  TarInfo Objects.    (line  145)
* devnull (in module os):                Miscellaneous System Information.
                                                             (line  158)
* DEVNULL (in module subprocess):        Using the subprocess Module.
                                                             (line  141)
* devpoll() (in module select):          select — Waiting for I/O completion.
                                                             (line   36)
* DevpollSelector (class in selectors):  Classes<4>.         (line  184)
* dgettext() (in module gettext):        GNU gettext API.    (line   39)
* dgettext() (in module locale):         Access to message catalogs.
                                                             (line    8)
* Dialect (class in csv):                Module Contents<2>. (line  188)
* dialect (csv.csvreader attribute):     Reader Objects.     (line   19)
* dialect (csv.csvwriter attribute):     Writer Objects.     (line   32)
* Dialog (class in tkinter.commondialog): tkinter commondialog — Dialog window templates.
                                                             (line   13)
* Dialog (class in tkinter.simpledialog): tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line   21)
* dict (built-in class):                 Mapping Types — dict.
                                                             (line   19)
* Dict (class in ast):                   Literals<3>.        (line  104)
* Dict (class in typing):                Aliases to built-in types.
                                                             (line    6)
* DICT_MERGE (opcode):                   Python Bytecode Instructions.
                                                             (line  742)
* DICT_UPDATE (opcode):                  Python Bytecode Instructions.
                                                             (line  731)
* dict() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  222)
* DictComp (class in ast):               Comprehensions.     (line    6)
* dictConfig() (in module logging.config): Configuration functions.
                                                             (line   13)
* dictionary:                            Glossary.           (line  462)
* dictionary comprehension:              Glossary.           (line  468)
* dictionary view:                       Glossary.           (line  476)
* dictionary; comprehensions:            Dictionary displays.
                                                             (line    6)
* dictionary; display:                   Dictionary displays.
                                                             (line    6)
* DictReader (class in csv):             Module Contents<2>. (line  105)
* DictWriter (class in csv):             Module Contents<2>. (line  152)
* diff_bytes() (in module difflib):      difflib — Helpers for computing deltas.
                                                             (line  336)
* diff_files (filecmp.dircmp attribute): The dircmp class.   (line   94)
* Differ (class in difflib):             difflib — Helpers for computing deltas.
                                                             (line   50)
* difference_update() (set method):      Set Types — set frozenset.
                                                             (line  184)
* difference() (frozenset method):       Set Types — set frozenset.
                                                             (line  112)
* difference() (set method):             Set Types — set frozenset.
                                                             (line  112)
* dig (sys.float_info attribute):        sys — System-specific parameters and functions.
                                                             (line  628)
* digest_size (hmac.HMAC attribute):     hmac — Keyed-Hashing for Message Authentication.
                                                             (line   94)
* digest() (hashlib.hash method):        Hash Objects.       (line   38)
* digest() (hashlib.shake method):       SHAKE variable length digests.
                                                             (line   15)
* digest() (hmac.HMAC method):           hmac — Keyed-Hashing for Message Authentication.
                                                             (line   60)
* digest() (in module hmac):             hmac — Keyed-Hashing for Message Authentication.
                                                             (line   33)
* digit() (in module unicodedata):       unicodedata — Unicode Database.
                                                             (line   62)
* digits (in module string):             String constants.   (line   24)
* dir() (ftplib.FTP method):             FTP objects.        (line  310)
* dircmp (class in filecmp):             The dircmp class.   (line    6)
* Directory (class in tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   71)
* directory; changing:                   Files and Directories.
                                                             (line  118)
* directory; creating:                   Files and Directories.
                                                             (line  544)
* directory; deleting:                   Directory and files operations.
                                                             (line  271)
* directory; deleting <1>:               Files and Directories.
                                                             (line  733)
* directory; traversal:                  Files and Directories.
                                                             (line 1640)
* directory; traversal <1>:              Files and Directories.
                                                             (line 1740)
* directory; walking:                    Files and Directories.
                                                             (line 1640)
* directory; walking <1>:                Files and Directories.
                                                             (line 1740)
* DirEntry (class in os):                Files and Directories.
                                                             (line  912)
* dirname() (in module os.path):         os path — Common pathname manipulations.
                                                             (line  109)
* dirs_double_event() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line   86)
* dirs_select_event() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line   90)
* DirsOnSysPath (class in test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   97)
* DIRTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  298)
* dis command line option; -C:           Command-line interface<10>.
                                                             (line   16)
* dis command line option; -h:           Command-line interface<10>.
                                                             (line   12)
* dis command line option; -help:        Command-line interface<10>.
                                                             (line   12)
* dis command line option; -O:           Command-line interface<10>.
                                                             (line   22)
* dis command line option; -show-caches: Command-line interface<10>.
                                                             (line   16)
* dis command line option; -show-offsets: Command-line interface<10>.
                                                             (line   22)
* dis() (dis.Bytecode method):           Bytecode analysis.  (line   57)
* dis() (in module dis):                 Analysis functions. (line   40)
* dis() (in module pickletools):         Programmatic Interface<2>.
                                                             (line    6)
* DISABLE (in module sys.monitoring):    Disabling events.   (line    6)
* disable (pdb command):                 Debugger commands.  (line  133)
* disable_faulthandler() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  356)
* disable_gc() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  368)
* disable_interspersed_args() (optparse.OptionParser method): Querying and manipulating your option parser.
                                                             (line   10)
* disable() (bdb.Breakpoint method):     bdb — Debugger framework.
                                                             (line   52)
* disable() (in module faulthandler):    Fault handler state.
                                                             (line   26)
* disable() (in module gc):              gc — Garbage Collector interface.
                                                             (line   26)
* disable() (in module logging):         Module-Level Functions.
                                                             (line  105)
* disable() (profile.Profile method):    profile and cProfile Module Reference.
                                                             (line   82)
* disabled (logging.Logger attribute):   Logger Objects.     (line   97)
* DisableReflectionKey() (in module winreg): Functions<13>.  (line  481)
* disassemble() (in module dis):         Analysis functions. (line   97)
* discard (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   57)
* discard() (mailbox.Mailbox method):    Mailbox objects.    (line   76)
* discard() (mailbox.MH method):         MH objects.         (line   79)
* discard() (set method):                Set Types — set frozenset.
                                                             (line  206)
* discover() (unittest.TestLoader method): Loading and running tests.
                                                             (line  116)
* disk_usage() (in module shutil):       Directory and files operations.
                                                             (line  382)
* dispatch_call() (bdb.Bdb method):      bdb — Debugger framework.
                                                             (line  205)
* dispatch_exception() (bdb.Bdb method): bdb — Debugger framework.
                                                             (line  225)
* dispatch_line() (bdb.Bdb method):      bdb — Debugger framework.
                                                             (line  195)
* dispatch_return() (bdb.Bdb method):    bdb — Debugger framework.
                                                             (line  215)
* dispatch_table (pickle.Pickler attribute): Module Interface.
                                                             (line  179)
* DISPLAY:                               Tkinter Modules.    (line   25)
* display (pdb command):                 Debugger commands.  (line  290)
* display_name (email.headerregistry.Address attribute): email headerregistry Custom Header Objects.
                                                             (line  425)
* display_name (email.headerregistry.Group attribute): email headerregistry Custom Header Objects.
                                                             (line  470)
* displayhook() (in module sys):         sys — System-specific parameters and functions.
                                                             (line  299)
* dist() (in module math):               Summation and product functions.
                                                             (line    6)
* distance() (in module turtle):         Tell Turtle’s state.
                                                             (line   68)
* distb() (in module dis):               Analysis functions. (line   80)
* Distribution (class in importlib.metadata): Distributions. (line   14)
* distribution() (in module importlib.metadata): Distributions.
                                                             (line    6)
* Div (class in ast):                    Expressions<2>.     (line   53)
* divide_int() (decimal.Context method): Context objects.    (line  306)
* divide() (decimal.Context method):     Context objects.    (line  302)
* division:                              Binary arithmetic operations.
                                                             (line   34)
* division (in module __future__):       Module Contents<4>. (line   22)
* DivisionByZero (class in decimal):     Signals.            (line   34)
* divmod() (decimal.Context method):     Context objects.    (line  310)
* DLE (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   72)
* DllCanUnloadNow() (in module ctypes):  Utility functions.  (line   95)
* DllGetClassObject() (in module ctypes): Utility functions. (line  103)
* dllhandle (in module sys):             sys — System-specific parameters and functions.
                                                             (line  293)
* dnd_start() (in module tkinter.dnd):   tkinter dnd — Drag and drop support.
                                                             (line   65)
* DndHandler (class in tkinter.dnd):     tkinter dnd — Drag and drop support.
                                                             (line   43)
* dngettext() (in module gettext):       GNU gettext API.    (line   58)
* dnpgettext() (in module gettext):      GNU gettext API.    (line   69)
* do_clear() (bdb.Bdb method):           bdb — Debugger framework.
                                                             (line  288)
* do_command() (curses.textpad.Textbox method): Textbox objects.
                                                             (line   30)
* do_GET() (http.server.SimpleHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  386)
* do_handshake() (ssl.SSLSocket method): SSL sockets.        (line  124)
* do_HEAD() (http.server.SimpleHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  379)
* do_help() (cmd.Cmd method):            Cmd Objects.        (line   48)
* do_POST() (http.server.CGIHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  473)
* doc (json.JSONDecodeError attribute):  Exceptions<17>.     (line   15)
* doc_header (cmd.Cmd attribute):        Cmd Objects.        (line  154)
* DocCGIXMLRPCRequestHandler (class in xmlrpc.server): Documenting XMLRPC server.
                                                             (line   22)
* DocFileSuite() (in module doctest):    Unittest API.       (line   24)
* doClassCleanups() (unittest.TestCase class method): Test cases.
                                                             (line  829)
* doCleanups() (unittest.TestCase method): Test cases.       (line  789)
* docmd() (smtplib.SMTP method):         SMTP Objects.       (line   17)
* docstring:                             Class definitions.  (line    6)
* docstring <1>:                         Glossary.           (line  486)
* docstring (doctest.DocTest attribute): DocTest Objects.    (line   48)
* docstrings:                            Defining Functions. (line   21)
* docstrings <1>:                        Documentation Strings.
                                                             (line    6)
* DocTest (class in doctest):            DocTest Objects.    (line    6)
* doctest command line option; -f:       Command-line Usage. (line   34)
* doctest command line option; -fail-fast: Command-line Usage.
                                                             (line   34)
* doctest command line option; -o:       Command-line Usage. (line   27)
* doctest command line option; -option:  Command-line Usage. (line   27)
* doctest command line option; -v:       Command-line Usage. (line   10)
* doctest command line option; -verbose: Command-line Usage. (line   10)
* DocTestFailure:                        Debugging.          (line  186)
* DocTestFinder (class in doctest):      DocTestFinder objects.
                                                             (line    6)
* DocTestParser (class in doctest):      DocTestParser objects.
                                                             (line    6)
* DocTestRunner (class in doctest):      DocTestRunner objects.
                                                             (line    6)
* DocTestSuite() (in module doctest):    Unittest API.       (line  100)
* doctype() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   67)
* documentation string:                  Special read-only attributes<2>.
                                                             (line  104)
* documentation strings:                 Defining Functions. (line   21)
* documentation strings <1>:             Documentation Strings.
                                                             (line    6)
* documentation; generation:             pydoc — Documentation generator and online help system.
                                                             (line    8)
* documentation; online:                 pydoc — Documentation generator and online help system.
                                                             (line    8)
* documentElement (xml.dom.Document attribute): Document Objects.
                                                             (line   10)
* DocXMLRPCRequestHandler (class in xmlrpc.server): Documenting XMLRPC server.
                                                             (line   27)
* DocXMLRPCServer (class in xmlrpc.server): Documenting XMLRPC server.
                                                             (line   11)
* does_esmtp (smtplib.SMTP attribute):   SMTP Objects.       (line  360)
* domain (email.headerregistry.Address attribute): email headerregistry Custom Header Objects.
                                                             (line  436)
* domain (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   40)
* domain (http.cookies.Morsel attribute): Morsel Objects.    (line   13)
* domain (tracemalloc.DomainFilter attribute): DomainFilter. (line   20)
* domain (tracemalloc.Filter attribute): Filter.             (line   31)
* domain (tracemalloc.Trace attribute):  Trace.              (line   15)
* domain_initial_dot (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   88)
* domain_return_ok() (http.cookiejar.CookiePolicy method): CookiePolicy Objects.
                                                             (line   27)
* domain_specified (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   84)
* DomainFilter (class in tracemalloc):   DomainFilter.       (line    6)
* DomainLiberal (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  156)
* DomainRFC2965Match (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  149)
* DomainStrict (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  161)
* DomainStrictNoDots (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  136)
* DomainStrictNonDomain (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  142)
* DOMEventStream (class in xml.dom.pulldom): DOMEventStream Objects.
                                                             (line    6)
* DOMException:                          Exceptions<20>.     (line   18)
* doModuleCleanups() (in module unittest): setUpModule and tearDownModule.
                                                             (line   45)
* DomstringSizeErr:                      Exceptions<20>.     (line   23)
* done() (asyncio.Future method):        Future Object.      (line   63)
* done() (asyncio.Task method):          Task object.        (line   66)
* done() (concurrent.futures.Future method): Future Objects. (line   32)
* done() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line  134)
* done() (in module turtle):             Using screen events.
                                                             (line  106)
* DONT_ACCEPT_BLANKLINE (in module doctest): Option Flags.   (line   28)
* DONT_ACCEPT_TRUE_FOR_1 (in module doctest): Option Flags.  (line   16)
* dont_write_bytecode (in module sys):   sys — System-specific parameters and functions.
                                                             (line  335)
* dont_write_bytecode (sys.flags attribute): sys — System-specific parameters and functions.
                                                             (line  542)
* doRollover() (logging.handlers.RotatingFileHandler method): RotatingFileHandler.
                                                             (line   43)
* doRollover() (logging.handlers.TimedRotatingFileHandler method): TimedRotatingFileHandler.
                                                             (line  106)
* DOT (in module token):                 token — Constants used with Python parse trees.
                                                             (line  224)
* dot() (in module turtle):              Turtle motion.      (line  252)
* DOTALL (in module re):                 Flags.              (line  108)
* doublequote (csv.Dialect attribute):   Dialects and Formatting Parameters.
                                                             (line   23)
* DOUBLESLASH (in module token):         token — Constants used with Python parse trees.
                                                             (line  296)
* DOUBLESLASHEQUAL (in module token):    token — Constants used with Python parse trees.
                                                             (line  299)
* DOUBLESTAR (in module token):          token — Constants used with Python parse trees.
                                                             (line  260)
* DOUBLESTAREQUAL (in module token):     token — Constants used with Python parse trees.
                                                             (line  293)
* doupdate() (in module curses):         Functions<6>.       (line   89)
* down (pdb command):                    Debugger commands.  (line   87)
* down() (in module turtle):             Drawing state.      (line    6)
* dpgettext() (in module gettext):       GNU gettext API.    (line   65)
* drain() (asyncio.StreamWriter method): StreamWriter.       (line   69)
* drive (pathlib.PurePath attribute):    Methods and properties.
                                                             (line   15)
* drop_whitespace (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  200)
* dropwhile() (in module itertools):     Itertool Functions. (line  268)
* dst() (datetime.datetime method):      datetime Objects.   (line  536)
* dst() (datetime.time method):          time Objects.       (line  245)
* dst() (datetime.timezone method):      timezone Objects.   (line   57)
* dst() (datetime.tzinfo method):        tzinfo Objects.     (line   63)
* DTDHandler (class in xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   24)
* duck-typing:                           Glossary.           (line  495)
* dump_stats() (profile.Profile method): profile and cProfile Module Reference.
                                                             (line  104)
* dump_stats() (pstats.Stats method):    The Stats Class.    (line   59)
* dump_traceback_later() (in module faulthandler): Dumping the tracebacks after a timeout.
                                                             (line    6)
* dump_traceback() (in module faulthandler): Dumping the traceback.
                                                             (line    6)
* dump() (in module ast):                ast Helpers.        (line  269)
* dump() (in module json):               Basic Usage.        (line    6)
* dump() (in module marshal):            marshal — Internal Python object serialization.
                                                             (line   51)
* dump() (in module pickle):             Module Interface.   (line   35)
* dump() (in module plistlib):           plistlib — Generate and parse Apple plist files.
                                                             (line   93)
* dump() (in module xml.etree.ElementTree): Functions<9>.    (line   86)
* dump() (pickle.Pickler method):        Module Interface.   (line  155)
* dump() (tracemalloc.Snapshot method):  Snapshot.           (line   29)
* dumps() (in module json):              Basic Usage.        (line   92)
* dumps() (in module marshal):           marshal — Internal Python object serialization.
                                                             (line   93)
* dumps() (in module pickle):            Module Interface.   (line   47)
* dumps() (in module plistlib):          plistlib — Generate and parse Apple plist files.
                                                             (line  130)
* dumps() (in module xmlrpc.client):     Convenience Functions.
                                                             (line    6)
* dunder:                                Glossary.           (line  508)
* dup() (in module os):                  File Descriptor Operations.
                                                             (line   93)
* dup() (socket.socket method):          Socket Objects.     (line  107)
* dup2() (in module os):                 File Descriptor Operations.
                                                             (line  107)
* DuplicateOptionError:                  Exceptions<8>.      (line   24)
* DuplicateSectionError:                 Exceptions<8>.      (line   14)
* dwFlags (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   19)
* DynamicClassAttribute() (in module types): Additional Utility Classes and Functions.
                                                             (line   54)
* e (in module cmath):                   Constants<3>.       (line   10)
* e (in module math):                    Constants<2>.       (line   10)
* e; in numeric literal:                 Integer literals.   (line   40)
* E2BIG (in module errno):               errno — Standard errno system symbols.
                                                             (line   54)
* EACCES (in module errno):              errno — Standard errno system symbols.
                                                             (line   80)
* EADDRINUSE (in module errno):          errno — Standard errno system symbols.
                                                             (line  432)
* EADDRNOTAVAIL (in module errno):       errno — Standard errno system symbols.
                                                             (line  436)
* EADV (in module errno):                errno — Standard errno system symbols.
                                                             (line  306)
* EAFNOSUPPORT (in module errno):        errno — Standard errno system symbols.
                                                             (line  428)
* EAFP:                                  Glossary.           (line  514)
* EAGAIN (in module errno):              errno — Standard errno system symbols.
                                                             (line   71)
* eager_task_factory() (in module asyncio): Eager task factory.
                                                             (line    6)
* EALREADY (in module errno):            errno — Standard errno system symbols.
                                                             (line  501)
* east_asian_width() (in module unicodedata): unicodedata — Unicode Database.
                                                             (line  108)
* EAUTH (in module errno):               errno — Standard errno system symbols.
                                                             (line  581)
* EBADARCH (in module errno):            errno — Standard errno system symbols.
                                                             (line  587)
* EBADE (in module errno):               errno — Standard errno system symbols.
                                                             (line  242)
* EBADEXEC (in module errno):            errno — Standard errno system symbols.
                                                             (line  593)
* EBADF (in module errno):               errno — Standard errno system symbols.
                                                             (line   62)
* EBADFD (in module errno):              errno — Standard errno system symbols.
                                                             (line  342)
* EBADMACHO (in module errno):           errno — Standard errno system symbols.
                                                             (line  599)
* EBADMSG (in module errno):             errno — Standard errno system symbols.
                                                             (line  330)
* EBADR (in module errno):               errno — Standard errno system symbols.
                                                             (line  246)
* EBADRPC (in module errno):             errno — Standard errno system symbols.
                                                             (line  665)
* EBADRQC (in module errno):             errno — Standard errno system symbols.
                                                             (line  258)
* EBADSLT (in module errno):             errno — Standard errno system symbols.
                                                             (line  262)
* EBFONT (in module errno):              errno — Standard errno system symbols.
                                                             (line  270)
* EBUSY (in module errno):               errno — Standard errno system symbols.
                                                             (line   93)
* ECANCELED (in module errno):           errno — Standard errno system symbols.
                                                             (line  692)
* ECHILD (in module errno):              errno — Standard errno system symbols.
                                                             (line   66)
* echo() (in module curses):             Functions<6>.       (line  105)
* echochar() (curses.window method):     Window Objects.     (line  197)
* ECHRNG (in module errno):              errno — Standard errno system symbols.
                                                             (line  210)
* ECOMM (in module errno):               errno — Standard errno system symbols.
                                                             (line  314)
* ECONNABORTED (in module errno):        errno — Standard errno system symbols.
                                                             (line  452)
* ECONNREFUSED (in module errno):        errno — Standard errno system symbols.
                                                             (line  488)
* ECONNRESET (in module errno):          errno — Standard errno system symbols.
                                                             (line  457)
* EDEADLK (in module errno):             errno — Standard errno system symbols.
                                                             (line  173)
* EDEADLOCK (in module errno):           errno — Standard errno system symbols.
                                                             (line  266)
* EDESTADDRREQ (in module errno):        errno — Standard errno system symbols.
                                                             (line  390)
* EDEVERR (in module errno):             errno — Standard errno system symbols.
                                                             (line  605)
* edit() (curses.textpad.Textbox method): Textbox objects.   (line   19)
* EDOM (in module errno):                errno — Standard errno system symbols.
                                                             (line  165)
* EDOTDOT (in module errno):             errno — Standard errno system symbols.
                                                             (line  326)
* EDQUOT (in module errno):              errno — Standard errno system symbols.
                                                             (line  535)
* EEXIST (in module errno):              errno — Standard errno system symbols.
                                                             (line   97)
* EFAULT (in module errno):              errno — Standard errno system symbols.
                                                             (line   85)
* EFBIG (in module errno):               errno — Standard errno system symbols.
                                                             (line  140)
* EFD_CLOEXEC (in module os):            Files and Directories.
                                                             (line 1914)
* EFD_NONBLOCK (in module os):           Files and Directories.
                                                             (line 1923)
* EFD_SEMAPHORE (in module os):          Files and Directories.
                                                             (line 1932)
* effective() (in module bdb):           bdb — Debugger framework.
                                                             (line  460)
* EFTYPE (in module errno):              errno — Standard errno system symbols.
                                                             (line  611)
* ehlo_or_helo_if_needed() (smtplib.SMTP method): SMTP Objects.
                                                             (line   75)
* ehlo_resp (smtplib.SMTP attribute):    SMTP Objects.       (line  356)
* ehlo() (smtplib.SMTP method):          SMTP Objects.       (line   58)
* EHOSTDOWN (in module errno):           errno — Standard errno system symbols.
                                                             (line  493)
* EHOSTUNREACH (in module errno):        errno — Standard errno system symbols.
                                                             (line  497)
* EIDRM (in module errno):               errno — Standard errno system symbols.
                                                             (line  206)
* EILSEQ (in module errno):              errno — Standard errno system symbols.
                                                             (line  370)
* EINPROGRESS (in module errno):         errno — Standard errno system symbols.
                                                             (line  506)
* EINTR (in module errno):               errno — Standard errno system symbols.
                                                             (line   41)
* EINVAL (in module errno):              errno — Standard errno system symbols.
                                                             (line  120)
* EIO (in module errno):                 errno — Standard errno system symbols.
                                                             (line   46)
* EISCONN (in module errno):             errno — Standard errno system symbols.
                                                             (line  466)
* EISDIR (in module errno):              errno — Standard errno system symbols.
                                                             (line  115)
* EISNAM (in module errno):              errno — Standard errno system symbols.
                                                             (line  527)
* EJECT (enum.FlagBoundary attribute):   Data types.         (line  747)
* EKEYEXPIRED (in module errno):         errno — Standard errno system symbols.
                                                             (line  557)
* EKEYREJECTED (in module errno):        errno — Standard errno system symbols.
                                                             (line  565)
* EKEYREVOKED (in module errno):         errno — Standard errno system symbols.
                                                             (line  561)
* EL2HLT (in module errno):              errno — Standard errno system symbols.
                                                             (line  238)
* EL2NSYNC (in module errno):            errno — Standard errno system symbols.
                                                             (line  214)
* EL3HLT (in module errno):              errno — Standard errno system symbols.
                                                             (line  218)
* EL3RST (in module errno):              errno — Standard errno system symbols.
                                                             (line  222)
* Element (class in xml.etree.ElementTree): Element Objects. (line    6)
* element_create() (tkinter.ttk.Style method): Ttk Styling.  (line  131)
* element_names() (tkinter.ttk.Style method): Ttk Styling.   (line  252)
* element_options() (tkinter.ttk.Style method): Ttk Styling. (line  256)
* ElementDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  289)
* elements() (collections.Counter method): Counter objects.  (line   71)
* ElementTree (class in xml.etree.ElementTree): ElementTree Objects.
                                                             (line    6)
* ELIBACC (in module errno):             errno — Standard errno system symbols.
                                                             (line  350)
* ELIBBAD (in module errno):             errno — Standard errno system symbols.
                                                             (line  354)
* ELIBEXEC (in module errno):            errno — Standard errno system symbols.
                                                             (line  366)
* ELIBMAX (in module errno):             errno — Standard errno system symbols.
                                                             (line  362)
* ELIBSCN (in module errno):             errno — Standard errno system symbols.
                                                             (line  358)
* Ellipsis (built-in variable):          Built-in Constants. (line   59)
* ELLIPSIS (in module doctest):          Option Flags.       (line   47)
* ELLIPSIS (in module token):            token — Constants used with Python parse trees.
                                                             (line  311)
* EllipsisType (in module types):        Standard Interpreter Types.
                                                             (line  144)
* ELNRNG (in module errno):              errno — Standard errno system symbols.
                                                             (line  226)
* ELOCKUNMAPPED (in module errno):       errno — Standard errno system symbols.
                                                             (line  573)
* ELOOP (in module errno):               errno — Standard errno system symbols.
                                                             (line  193)
* else; conditional expression:          Conditional expressions.
                                                             (line    6)
* EM (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   99)
* EmailMessage (class in email.message): email message Representing an email message.
                                                             (line   52)
* EmailPolicy (class in email.policy):   email policy Policy Objects.
                                                             (line  359)
* Emax (decimal.Context attribute):      Context objects.    (line  139)
* EMEDIUMTYPE (in module errno):         errno — Standard errno system symbols.
                                                             (line  549)
* EMFILE (in module errno):              errno — Standard errno system symbols.
                                                             (line  128)
* Emin (decimal.Context attribute):      Context objects.    (line  139)
* emit() (logging.FileHandler method):   FileHandler.        (line   30)
* emit() (logging.Handler method):       Handler Objects.    (line  109)
* emit() (logging.handlers.BufferingHandler method): MemoryHandler.
                                                             (line   24)
* emit() (logging.handlers.DatagramHandler method): DatagramHandler.
                                                             (line   29)
* emit() (logging.handlers.HTTPHandler method): HTTPHandler. (line   36)
* emit() (logging.handlers.NTEventLogHandler method): NTEventLogHandler.
                                                             (line   38)
* emit() (logging.handlers.QueueHandler method): QueueHandler.
                                                             (line   42)
* emit() (logging.handlers.RotatingFileHandler method): RotatingFileHandler.
                                                             (line   47)
* emit() (logging.handlers.SMTPHandler method): SMTPHandler. (line   34)
* emit() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   24)
* emit() (logging.handlers.SysLogHandler method): SysLogHandler.
                                                             (line   61)
* emit() (logging.handlers.TimedRotatingFileHandler method): TimedRotatingFileHandler.
                                                             (line  110)
* emit() (logging.handlers.WatchedFileHandler method): WatchedFileHandler.
                                                             (line   50)
* emit() (logging.NullHandler method):   NullHandler.        (line   16)
* emit() (logging.StreamHandler method): StreamHandler.      (line   17)
* EMLINK (in module errno):              errno — Standard errno system symbols.
                                                             (line  156)
* Empty:                                 queue — A synchronized queue class.
                                                             (line   80)
* empty (inspect.Parameter attribute):   Introspecting callables with the Signature object.
                                                             (line  198)
* empty (inspect.Signature attribute):   Introspecting callables with the Signature object.
                                                             (line   99)
* EMPTY_NAMESPACE (in module xml.dom):   Module Contents<3>. (line   35)
* empty; list:                           List displays.      (line    6)
* empty; tuple:                          Immutable sequences.
                                                             (line   29)
* empty; tuple <1>:                      Parenthesized forms.
                                                             (line   16)
* empty() (asyncio.Queue method):        Queue.              (line   27)
* empty() (multiprocessing.Queue method): Pipes and Queues.  (line  118)
* empty() (multiprocessing.SimpleQueue method): Pipes and Queues.
                                                             (line  240)
* empty() (queue.Queue method):          Queue Objects.      (line   15)
* empty() (queue.SimpleQueue method):    SimpleQueue Objects.
                                                             (line   14)
* empty() (sched.scheduler method):      Scheduler Objects.  (line   47)
* emptyline() (cmd.Cmd method):          Cmd Objects.        (line   69)
* emscripten_version (sys._emscripten_info attribute): sys — System-specific parameters and functions.
                                                             (line  349)
* EMSGSIZE (in module errno):            errno — Standard errno system symbols.
                                                             (line  394)
* EMULTIHOP (in module errno):           errno — Standard errno system symbols.
                                                             (line  322)
* enable (pdb command):                  Debugger commands.  (line  140)
* enable_callback_tracebacks() (in module sqlite3): Module functions.
                                                             (line  125)
* enable_interspersed_args() (optparse.OptionParser method): Querying and manipulating your option parser.
                                                             (line   31)
* enable_load_extension() (sqlite3.Connection method): Connection objects.
                                                             (line  425)
* enable_traversal() (tkinter.ttk.Notebook method): ttk Notebook.
                                                             (line   75)
* ENABLE_USER_SITE (in module site):     Module contents<6>. (line   10)
* enable() (bdb.Breakpoint method):      bdb — Debugger framework.
                                                             (line   48)
* enable() (imaplib.IMAP4 method):       IMAP4 Objects.      (line   84)
* enable() (in module faulthandler):     Fault handler state.
                                                             (line    6)
* enable() (in module gc):               gc — Garbage Collector interface.
                                                             (line   22)
* enable() (profile.Profile method):     profile and cProfile Module Reference.
                                                             (line   78)
* EnableControlFlowGuard:                Build<41>.          (line   47)
* enabled (bdb.Breakpoint attribute):    bdb — Debugger framework.
                                                             (line  103)
* EnableReflectionKey() (in module winreg): Functions<13>.   (line  499)
* ENAMETOOLONG (in module errno):        errno — Standard errno system symbols.
                                                             (line  177)
* ENAVAIL (in module errno):             errno — Standard errno system symbols.
                                                             (line  523)
* enclose() (curses.window method):      Window Objects.     (line  202)
* encode (codecs.CodecInfo attribute):   codecs — Codec registry and base classes.
                                                             (line   78)
* encode_7or8bit() (in module email.encoders): email encoders Encoders.
                                                             (line   57)
* encode_base64() (in module email.encoders): email encoders Encoders.
                                                             (line   49)
* encode_noop() (in module email.encoders): email encoders Encoders.
                                                             (line   63)
* encode_quopri() (in module email.encoders): email encoders Encoders.
                                                             (line   42)
* encode_rfc2231() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  190)
* encode() (codecs.Codec method):        Stateless Encoding and Decoding.
                                                             (line   11)
* encode() (codecs.IncrementalEncoder method): IncrementalEncoder Objects.
                                                             (line   28)
* encode() (email.header.Header method): email header Internationalized headers.
                                                             (line  124)
* encode() (in module base64):           Legacy Interface.   (line   21)
* encode() (in module codecs):           codecs — Codec registry and base classes.
                                                             (line   23)
* encode() (in module quopri):           quopri — Encode and decode MIME quoted-printable data.
                                                             (line   29)
* encode() (json.JSONEncoder method):    Encoders and Decoders.
                                                             (line  221)
* encode() (str method):                 String Methods<2>.  (line   88)
* encode() (xmlrpc.client.Binary method): Binary Objects.    (line   25)
* encode() (xmlrpc.client.DateTime method): DateTime Objects.
                                                             (line   17)
* encodebytes() (in module base64):      Legacy Interface.   (line   31)
* EncodedFile() (in module codecs):      codecs — Codec registry and base classes.
                                                             (line  211)
* encodePriority() (logging.handlers.SysLogHandler method): SysLogHandler.
                                                             (line   95)
* encodestring() (in module quopri):     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   46)
* encoding (curses.window attribute):    Window Objects.     (line  212)
* ENCODING (in module tarfile):          tarfile — Read and write tar archive files.
                                                             (line  272)
* ENCODING (in module token):            token — Constants used with Python parse trees.
                                                             (line  126)
* encoding (io.TextIOBase attribute):    Text I/O<2>.        (line   15)
* encoding (UnicodeError attribute):     Concrete exceptions.
                                                             (line  443)
* encoding declarations (source file):   Encoding declarations.
                                                             (line    6)
* encodings_map (in module mimetypes):   mimetypes — Map filenames to MIME types.
                                                             (line  149)
* encodings_map (mimetypes.MimeTypes attribute): MimeTypes Objects.
                                                             (line   33)
* EncodingWarning:                       Warnings.           (line   72)
* end (UnicodeError attribute):          Concrete exceptions.
                                                             (line  459)
* END_ASYNC_FOR (opcode):                Python Bytecode Instructions.
                                                             (line  338)
* end_col_offset (ast.AST attribute):    Node classes.       (line   50)
* end_colno (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   62)
* end_fill() (in module turtle):         Filling.            (line   20)
* END_FOR (opcode):                      Python Bytecode Instructions.
                                                             (line  145)
* end_headers() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  278)
* end_lineno (ast.AST attribute):        Node classes.       (line   50)
* end_lineno (SyntaxError attribute):    Concrete exceptions.
                                                             (line  335)
* end_lineno (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   49)
* end_lineno (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   99)
* end_ns() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   86)
* end_offset (SyntaxError attribute):    Concrete exceptions.
                                                             (line  341)
* end_offset (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line  115)
* end_poly() (in module turtle):         Special Turtle methods.
                                                             (line   11)
* END_SEND (opcode):                     Python Bytecode Instructions.
                                                             (line  152)
* end() (re.Match method):               Match Objects.      (line  146)
* end() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   38)
* endCDATA() (xml.sax.handler.LexicalHandler method): LexicalHandler Objects.
                                                             (line   39)
* EndCdataSectionHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  396)
* EndDoctypeDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  284)
* endDocument() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   40)
* endDTD() (xml.sax.handler.LexicalHandler method): LexicalHandler Objects.
                                                             (line   28)
* endElement() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   93)
* EndElementHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  319)
* endElementNS() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  118)
* endheaders() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  189)
* ENDMARKER (in module token):           token — Constants used with Python parse trees.
                                                             (line  122)
* EndNamespaceDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  375)
* endpos (re.Match attribute):           Match Objects.      (line  185)
* endPrefixMapping() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   72)
* endswith() (bytearray method):         Bytes and Bytearray Operations.
                                                             (line  122)
* endswith() (bytes method):             Bytes and Bytearray Operations.
                                                             (line  122)
* endswith() (str method):               String Methods<2>.  (line  119)
* endwin() (in module curses):           Functions<6>.       (line  110)
* ENEEDAUTH (in module errno):           errno — Standard errno system symbols.
                                                             (line  617)
* ENETDOWN (in module errno):            errno — Standard errno system symbols.
                                                             (line  440)
* ENETRESET (in module errno):           errno — Standard errno system symbols.
                                                             (line  448)
* ENETUNREACH (in module errno):         errno — Standard errno system symbols.
                                                             (line  444)
* ENFILE (in module errno):              errno — Standard errno system symbols.
                                                             (line  124)
* ENOANO (in module errno):              errno — Standard errno system symbols.
                                                             (line  254)
* ENOATTR (in module errno):             errno — Standard errno system symbols.
                                                             (line  623)
* ENOBUFS (in module errno):             errno — Standard errno system symbols.
                                                             (line  462)
* ENOCSI (in module errno):              errno — Standard errno system symbols.
                                                             (line  234)
* ENODATA (in module errno):             errno — Standard errno system symbols.
                                                             (line  278)
* ENODEV (in module errno):              errno — Standard errno system symbols.
                                                             (line  106)
* ENOENT (in module errno):              errno — Standard errno system symbols.
                                                             (line   31)
* ENOEXEC (in module errno):             errno — Standard errno system symbols.
                                                             (line   58)
* ENOKEY (in module errno):              errno — Standard errno system symbols.
                                                             (line  553)
* ENOLCK (in module errno):              errno — Standard errno system symbols.
                                                             (line  181)
* ENOLINK (in module errno):             errno — Standard errno system symbols.
                                                             (line  302)
* ENOMEDIUM (in module errno):           errno — Standard errno system symbols.
                                                             (line  545)
* ENOMEM (in module errno):              errno — Standard errno system symbols.
                                                             (line   76)
* ENOMSG (in module errno):              errno — Standard errno system symbols.
                                                             (line  202)
* ENONET (in module errno):              errno — Standard errno system symbols.
                                                             (line  290)
* ENOPKG (in module errno):              errno — Standard errno system symbols.
                                                             (line  294)
* ENOPOLICY (in module errno):           errno — Standard errno system symbols.
                                                             (line  629)
* ENOPROTOOPT (in module errno):         errno — Standard errno system symbols.
                                                             (line  402)
* ENOSPC (in module errno):              errno — Standard errno system symbols.
                                                             (line  144)
* ENOSR (in module errno):               errno — Standard errno system symbols.
                                                             (line  286)
* ENOSTR (in module errno):              errno — Standard errno system symbols.
                                                             (line  274)
* ENOSYS (in module errno):              errno — Standard errno system symbols.
                                                             (line  185)
* ENOTACTIVE (in module errno):          errno — Standard errno system symbols.
                                                             (line  577)
* ENOTBLK (in module errno):             errno — Standard errno system symbols.
                                                             (line   89)
* ENOTCAPABLE (in module errno):         errno — Standard errno system symbols.
                                                             (line  683)
* ENOTCONN (in module errno):            errno — Standard errno system symbols.
                                                             (line  470)
* ENOTDIR (in module errno):             errno — Standard errno system symbols.
                                                             (line  110)
* ENOTEMPTY (in module errno):           errno — Standard errno system symbols.
                                                             (line  189)
* ENOTNAM (in module errno):             errno — Standard errno system symbols.
                                                             (line  519)
* ENOTRECOVERABLE (in module errno):     errno — Standard errno system symbols.
                                                             (line  704)
* ENOTSOCK (in module errno):            errno — Standard errno system symbols.
                                                             (line  386)
* ENOTSUP (in module errno):             errno — Standard errno system symbols.
                                                             (line  418)
* ENOTTY (in module errno):              errno — Standard errno system symbols.
                                                             (line  132)
* ENOTUNIQ (in module errno):            errno — Standard errno system symbols.
                                                             (line  338)
* ENQ (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   33)
* enqueue_sentinel() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   93)
* enqueue() (logging.handlers.QueueHandler method): QueueHandler.
                                                             (line   85)
* ensure_directories() (venv.EnvBuilder method): API<2>.     (line   90)
* ensure_future() (in module asyncio):   Future Functions.   (line   19)
* ensurepip command line option; -altinstall: Command-line interface<7>.
                                                             (line   42)
* ensurepip command line option; -default-pip: Command-line interface<7>.
                                                             (line   47)
* ensurepip command line option; -root:  Command-line interface<7>.
                                                             (line   25)
* ensurepip command line option; -user:  Command-line interface<7>.
                                                             (line   31)
* enter_async_context() (contextlib.AsyncExitStack method): Utilities.
                                                             (line  630)
* enter_context() (contextlib.ExitStack method): Utilities.  (line  545)
* enter() (sched.scheduler method):      Scheduler Objects.  (line   30)
* enterabs() (sched.scheduler method):   Scheduler Objects.  (line    9)
* enterAsyncContext() (unittest.IsolatedAsyncioTestCase method): Test cases.
                                                             (line  889)
* enterClassContext() (unittest.TestCase class method): Test cases.
                                                             (line  820)
* enterContext() (unittest.TestCase method): Test cases.     (line  780)
* enterModuleContext() (in module unittest): setUpModule and tearDownModule.
                                                             (line   36)
* entities (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   38)
* EntityDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  348)
* entitydefs (in module html.entities):  html entities — Definitions of HTML general entities.
                                                             (line   25)
* EntityResolver (class in xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   31)
* entry_points() (in module importlib.metadata): Entry points.
                                                             (line    6)
* EntryPoint (class in importlib.metadata): Entry points.    (line   26)
* EntryPoints (class in importlib.metadata): Entry points.   (line   18)
* Enum (class in enum):                  Data types.         (line  120)
* enum_certificates() (in module ssl):   Certificate handling.
                                                             (line   87)
* enum_crls() (in module ssl):           Certificate handling.
                                                             (line  110)
* EnumCheck (class in enum):             Data types.         (line  651)
* EnumDict (class in enum):              Data types.         (line  778)
* enumerate() (in module threading):     Reference<2>.       (line   98)
* EnumKey() (in module winreg):          Functions<13>.      (line  172)
* EnumType (class in enum):              Data types.         (line    6)
* EnumValue() (in module winreg):        Functions<13>.      (line  191)
* EnvBuilder (class in venv):            API<2>.             (line   11)
* environ (in module os):                Process Parameters. (line   16)
* environ (in module posix):             Notable Module Contents.
                                                             (line    9)
* environb (in module os):               Process Parameters. (line   57)
* environment:                           Resolution of names.
                                                             (line   12)
* environment variable; __PYVENV_LAUNCHER__: PyConfig.       (line  183)
* environment variable; __PYVENV_LAUNCHER__ <1>: PyConfig.   (line  699)
* environment variable; BASECFLAGS:      Compiler flags.     (line   66)
* environment variable; BASECPPFLAGS:    Preprocessor flags. (line   22)
* environment variable; BLDSHARED:       Linker flags.       (line   67)
* environment variable; BROWSER:         webbrowser — Convenient web-browser controller.
                                                             (line   20)
* environment variable; BROWSER <1>:     webbrowser — Convenient web-browser controller.
                                                             (line   34)
* environment variable; BROWSER <2>:     Command-line interface<4>.
                                                             (line   86)
* environment variable; CC:              New Improved and Deprecated Modules<4>.
                                                             (line   58)
* environment variable; CC <1>:          Compiler flags.     (line    6)
* environment variable; CCSHARED:        Compiler flags.     (line   81)
* environment variable; CFLAGS:          New Improved and Deprecated Modules<4>.
                                                             (line   59)
* environment variable; CFLAGS <1>:      Performance options.
                                                             (line   28)
* environment variable; CFLAGS <2>:      Compiler flags.     (line   18)
* environment variable; CFLAGS <3>:      Compiler flags.     (line   26)
* environment variable; CFLAGS <4>:      Compiler flags.     (line   28)
* environment variable; CFLAGS <5>:      Compiler flags.     (line   32)
* environment variable; CFLAGS <6>:      Compiler flags.     (line   54)
* environment variable; CFLAGS <7>:      Linker flags.       (line   18)
* environment variable; CFLAGS_ALIASING: Compiler flags.     (line   74)
* environment variable; CFLAGS_NODIST:   Compiler flags.     (line   22)
* environment variable; CFLAGS_NODIST <1>: Compiler flags.   (line   24)
* environment variable; CFLAGS_NODIST <2>: Compiler flags.   (line   61)
* environment variable; CFLAGS_NODIST <3>: Linker flags.     (line   26)
* environment variable; CFLAGSFORSHARED: Compiler flags.     (line   87)
* environment variable; COLUMNS:         Functions<6>.       (line  593)
* environment variable; COLUMNS <1>:     Functions<6>.       (line  596)
* environment variable; COMPILEALL_OPTS: Compiler flags.     (line   41)
* environment variable; COMSPEC:         Process Management. (line  770)
* environment variable; COMSPEC <1>:     Popen Constructor.  (line  112)
* environment variable; CONFIGURE_CFLAGS: Compiler flags.    (line   52)
* environment variable; CONFIGURE_CFLAGS_NODIST: Compiler flags.
                                                             (line   59)
* environment variable; CONFIGURE_CPPFLAGS: Preprocessor flags.
                                                             (line    6)
* environment variable; CONFIGURE_LDFLAGS: Linker flags.     (line   13)
* environment variable; CONFIGURE_LDFLAGS_NODIST: Linker flags.
                                                             (line   38)
* environment variable; CPPFLAGS:        New Improved and Deprecated Modules<4>.
                                                             (line   59)
* environment variable; CPPFLAGS <1>:    Preprocessor flags. (line    8)
* environment variable; CPPFLAGS <2>:    Preprocessor flags. (line   13)
* environment variable; CPPFLAGS <3>:    Preprocessor flags. (line   18)
* environment variable; CPPFLAGS <4>:    Linker flags.       (line   50)
* environment variable; CXX:             Compiler flags.     (line   12)
* environment variable; DISPLAY:         Tkinter Modules.    (line   25)
* environment variable; EnableControlFlowGuard: Build<41>.   (line   47)
* environment variable; EXTRA_CFLAGS:    Compiler flags.     (line   48)
* environment variable; HOME:            os path<5>.         (line   15)
* environment variable; HOME <1>:        Changes in the Python API<5>.
                                                             (line  118)
* environment variable; HOME <2>:        Windows<46>.        (line   15)
* environment variable; HOME <3>:        Windows<46>.        (line   18)
* environment variable; HOME <4>:        os path — Common pathname manipulations.
                                                             (line  143)
* environment variable; HOME <5>:        os path — Common pathname manipulations.
                                                             (line  160)
* environment variable; HOME <6>:        Tkinter Modules.    (line   64)
* environment variable; HOMEDRIVE:       os path — Common pathname manipulations.
                                                             (line  150)
* environment variable; HOMEPATH:        os path — Common pathname manipulations.
                                                             (line  150)
* environment variable; IDLESTARTUP:     IDLE<41>.           (line  176)
* environment variable; IDLESTARTUP <1>: IDLE<45>.           (line    9)
* environment variable; IDLESTARTUP <2>: IDLE<51>.           (line    9)
* environment variable; IDLESTARTUP <3>: Startup and Code Execution.
                                                             (line    7)
* environment variable; IDLESTARTUP <4>: Command-line usage<3>.
                                                             (line   41)
* environment variable; LANG:            GNU gettext API.    (line   21)
* environment variable; LANG <1>:        Class-based API.    (line   26)
* environment variable; LANG <2>:        locale — Internationalization services.
                                                             (line   62)
* environment variable; LANG <3>:        locale — Internationalization services.
                                                             (line  358)
* environment variable; LANG <4>:        locale — Internationalization services.
                                                             (line  362)
* environment variable; LANGUAGE:        GNU gettext API.    (line   20)
* environment variable; LANGUAGE <1>:    Class-based API.    (line   25)
* environment variable; LC_ALL:          GNU gettext API.    (line   20)
* environment variable; LC_ALL <1>:      Class-based API.    (line   25)
* environment variable; LC_MESSAGES:     GNU gettext API.    (line   20)
* environment variable; LC_MESSAGES <1>: Class-based API.    (line   26)
* environment variable; LDFLAGS:         New Improved and Deprecated Modules<4>.
                                                             (line   59)
* environment variable; LDFLAGS <1>:     Preprocessor flags. (line   18)
* environment variable; LDFLAGS <2>:     Linker flags.       (line   15)
* environment variable; LDFLAGS <3>:     Linker flags.       (line   18)
* environment variable; LDFLAGS <4>:     Linker flags.       (line   28)
* environment variable; LDFLAGS <5>:     Linker flags.       (line   31)
* environment variable; LDFLAGS <6>:     Linker flags.       (line   35)
* environment variable; LDFLAGS <7>:     Linker flags.       (line   45)
* environment variable; LDFLAGS <8>:     Linker flags.       (line   50)
* environment variable; LDFLAGS_NODIST:  Linker flags.       (line   24)
* environment variable; LDFLAGS_NODIST <1>: Linker flags.    (line   26)
* environment variable; LDFLAGS_NODIST <2>: Linker flags.    (line   40)
* environment variable; LDSHARED:        Linker flags.       (line   61)
* environment variable; LIBS:            Linker flags.       (line   54)
* environment variable; LINES:           Functions<6>.       (line  125)
* environment variable; LINES <1>:       Functions<6>.       (line  593)
* environment variable; LINES <2>:       Functions<6>.       (line  595)
* environment variable; LINKCC:          Linker flags.       (line    6)
* environment variable; LOGNAME:         Process Parameters. (line  234)
* environment variable; LOGNAME <1>:     getpass — Portable password input.
                                                             (line   43)
* environment variable; MANPAGER:        pydoc — Documentation generator and online help system.
                                                             (line   46)
* environment variable; MANPAGER <1>:    pydoc — Documentation generator and online help system.
                                                             (line   48)
* environment variable; no_proxy:        urllib request — Extensible library for opening URLs.
                                                             (line  309)
* environment variable; OPT:             Debug options.      (line   39)
* environment variable; OPT <1>:         Compiler flags.     (line   70)
* environment variable; PAGER:           pydoc — Documentation generator and online help system.
                                                             (line   46)
* environment variable; PATH:            Changes in the Python API<5>.
                                                             (line  145)
* environment variable; PATH <1>:        Changes in ‘python’ Command Behavior<2>.
                                                             (line    6)
* environment variable; PATH <2>:        Changes in ‘python’ Command Behavior<2>.
                                                             (line   11)
* environment variable; PATH <3>:        Changes in ‘python’ Command Behavior<2>.
                                                             (line   12)
* environment variable; PATH <4>:        macOS<9>.           (line   14)
* environment variable; PATH <5>:        Windows<27>.        (line   55)
* environment variable; PATH <6>:        Windows<31>.        (line   14)
* environment variable; PATH <7>:        Security<41>.       (line   16)
* environment variable; PATH <8>:        Security<41>.       (line   20)
* environment variable; PATH <9>:        The Module Search Path.
                                                             (line   17)
* environment variable; PATH <10>:       Executable Python Scripts.
                                                             (line   11)
* environment variable; PATH <11>:       Environment variables.
                                                             (line   26)
* environment variable; PATH <12>:       Miscellaneous.      (line   16)
* environment variable; PATH <13>:       Installation steps. (line   34)
* environment variable; PATH <14>:       Installation steps. (line   58)
* environment variable; PATH <15>:       Installing Without UI.
                                                             (line   77)
* environment variable; PATH <16>:       Installing Without UI.
                                                             (line   81)
* environment variable; PATH <17>:       Excursus Setting environment variables.
                                                             (line   23)
* environment variable; PATH <18>:       Excursus Setting environment variables.
                                                             (line   35)
* environment variable; PATH <19>:       Finding the Python executable.
                                                             (line   14)
* environment variable; PATH <20>:       Finding the Python executable.
                                                             (line   21)
* environment variable; PATH <21>:       Finding the Python executable.
                                                             (line   22)
* environment variable; PATH <22>:       Python Launcher for Windows.
                                                             (line   13)
* environment variable; PATH <23>:       From the command-line.
                                                             (line    9)
* environment variable; PATH <24>:       Shebang Lines.      (line   54)
* environment variable; PATH <25>:       Shebang Lines.      (line   60)
* environment variable; PATH <26>:       Shebang Lines.      (line   62)
* environment variable; PATH <27>:       Shebang Lines.      (line   67)
* environment variable; PATH <28>:       Comparison to the os and os path modules.
                                                             (line   41)
* environment variable; PATH <29>:       Directory and files operations.
                                                             (line  431)
* environment variable; PATH <30>:       Directory and files operations.
                                                             (line  436)
* environment variable; PATH <31>:       Process Management. (line   45)
* environment variable; PATH <32>:       Process Management. (line   84)
* environment variable; PATH <33>:       Process Management. (line   88)
* environment variable; PATH <34>:       Process Management. (line   89)
* environment variable; PATH <35>:       Process Management. (line  540)
* environment variable; PATH <36>:       Process Management. (line  626)
* environment variable; PATH <37>:       Process Management. (line  630)
* environment variable; PATH <38>:       Process Management. (line  631)
* environment variable; PATH <39>:       Miscellaneous System Information.
                                                             (line  140)
* environment variable; PATH <40>:       Popen Constructor.  (line   34)
* environment variable; PATH <41>:       webbrowser — Convenient web-browser controller.
                                                             (line   52)
* environment variable; PATH <42>:       How venvs work.     (line   16)
* environment variable; PATH <43>:       How venvs work.     (line   61)
* environment variable; PATH <44>:       How venvs work.     (line   66)
* environment variable; PATH <45>:       site — Site-specific configuration hook.
                                                             (line   66)
* environment variable; PATH <46>:       Embedding Python<2>.
                                                             (line   31)
* environment variable; PATH <47>:       Embedding Python<2>.
                                                             (line   37)
* environment variable; PATH <48>:       How do I make a Python script executable on Unix?.
                                                             (line   24)
* environment variable; PATH <49>:       How do I make a Python script executable on Unix?.
                                                             (line   28)
* environment variable; PATHEXT:         Other Improvements<2>.
                                                             (line   30)
* environment variable; PATHEXT <1>:     Library<111>.       (line  138)
* environment variable; PATHEXT <2>:     Installing Without UI.
                                                             (line   77)
* environment variable; PATHEXT <3>:     Installing Without UI.
                                                             (line   81)
* environment variable; PATHEXT <4>:     Directory and files operations.
                                                             (line  446)
* environment variable; PIP_USER:        Windows<48>.        (line  102)
* environment variable; PROFILE_TASK:    Build<21>.          (line   13)
* environment variable; PROFILE_TASK <1>: Performance options.
                                                             (line   12)
* environment variable; PROFILE_TASK <2>: Performance options.
                                                             (line   34)
* environment variable; PURIFY:          Compiler flags.     (line  130)
* environment variable; PY_BUILTIN_MODULE_CFLAGS: Compiler flags.
                                                             (line  121)
* environment variable; PY_CFLAGS:       Compiler flags.     (line   94)
* environment variable; PY_CFLAGS_NODIST: Compiler flags.    (line   99)
* environment variable; PY_CORE_CFLAGS:  Compiler flags.     (line  115)
* environment variable; PY_CORE_LDFLAGS: Linker flags.       (line   83)
* environment variable; PY_CPPFLAGS:     Preprocessor flags. (line   26)
* environment variable; PY_LDFLAGS:      Linker flags.       (line   73)
* environment variable; PY_LDFLAGS_NODIST: Linker flags.     (line   77)
* environment variable; PY_STDMODULE_CFLAGS: Compiler flags. (line  106)
* environment variable; PYLAUNCHER_ALLOW_INSTALL: Windows<15>.
                                                             (line   24)
* environment variable; PYLAUNCHER_ALLOW_INSTALL <1>: Windows<29>.
                                                             (line   15)
* environment variable; PYTHON_BASIC_REPL: A better interactive interpreter.
                                                             (line   27)
* environment variable; PYTHON_BASIC_REPL <1>: Library<17>.  (line  322)
* environment variable; PYTHON_BASIC_REPL <2>: Library<17>.  (line  325)
* environment variable; PYTHON_BASIC_REPL <3>: Core and Builtins<23>.
                                                             (line   12)
* environment variable; PYTHON_BASIC_REPL <4>: Interactive Mode<2>.
                                                             (line   23)
* environment variable; PYTHON_BASIC_REPL <5>: Environment variables.
                                                             (line  518)
* environment variable; PYTHON_BASIC_REPL <6>: Example.      (line   79)
* environment variable; PYTHON_BASIC_REPL <7>: asyncio — Asynchronous I/O.
                                                             (line   81)
* environment variable; PYTHON_COLORS:   Summary – Release Highlights.
                                                             (line   57)
* environment variable; PYTHON_COLORS <1>: Improved error messages.
                                                             (line    8)
* environment variable; PYTHON_COLORS <2>: doctest.          (line    7)
* environment variable; PYTHON_COLORS <3>: Controlling color.
                                                             (line   22)
* environment variable; PYTHON_COLORS <4>: Environment variables.
                                                             (line  510)
* environment variable; PYTHON_CPU_COUNT: os.                (line   11)
* environment variable; PYTHON_CPU_COUNT <1>: Miscellaneous options.
                                                             (line  376)
* environment variable; PYTHON_CPU_COUNT <2>: Environment variables.
                                                             (line  486)
* environment variable; PYTHON_CPU_COUNT <3>: Miscellaneous System Information.
                                                             (line   48)
* environment variable; PYTHON_CPU_COUNT <4>: Miscellaneous System Information.
                                                             (line   69)
* environment variable; PYTHON_CPU_COUNT <5>: Miscellaneous<3>.
                                                             (line   31)
* environment variable; PYTHON_CPU_COUNT <6>: PyConfig.      (line  493)
* environment variable; PYTHON_DOM:      Module Contents<3>. (line   23)
* environment variable; PYTHON_FROZEN_MODULES: Other Language Changes.
                                                             (line   46)
* environment variable; PYTHON_FROZEN_MODULES <1>: Core and Builtins<34>.
                                                             (line  105)
* environment variable; PYTHON_FROZEN_MODULES <2>: Miscellaneous options.
                                                             (line  347)
* environment variable; PYTHON_FROZEN_MODULES <3>: Environment variables.
                                                             (line  496)
* environment variable; PYTHON_GIL:      Free-threaded CPython.
                                                             (line   22)
* environment variable; PYTHON_GIL <1>:  Free-threaded CPython.
                                                             (line   38)
* environment variable; PYTHON_GIL <2>:  Core and Builtins<19>.
                                                             (line   36)
* environment variable; PYTHON_GIL <3>:  Miscellaneous options.
                                                             (line  394)
* environment variable; PYTHON_GIL <4>:  Environment variables.
                                                             (line  535)
* environment variable; PYTHON_GIL <5>:  The global interpreter lock in free-threaded Python.
                                                             (line    7)
* environment variable; PYTHON_GIL <6>:  Glossary.           (line  745)
* environment variable; PYTHON_HISTORY:  Other Language Changes.
                                                             (line   57)
* environment variable; PYTHON_HISTORY <1>: Library<37>.     (line  544)
* environment variable; PYTHON_HISTORY <2>: Environment variables.
                                                             (line  527)
* environment variable; PYTHON_JIT:      An experimental just-in-time JIT compiler.
                                                             (line   21)
* environment variable; PYTHON_JIT <1>:  An experimental just-in-time JIT compiler.
                                                             (line   24)
* environment variable; PYTHON_JIT <2>:  An experimental just-in-time JIT compiler.
                                                             (line   28)
* environment variable; PYTHON_JIT <3>:  Environment variables.
                                                             (line  547)
* environment variable; PYTHON_PERF_JIT_SUPPORT: Other Language Changes.
                                                             (line   52)
* environment variable; PYTHON_PERF_JIT_SUPPORT <1>: Miscellaneous options.
                                                             (line  366)
* environment variable; PYTHON_PERF_JIT_SUPPORT <2>: Environment variables.
                                                             (line  473)
* environment variable; PYTHON_PERF_JIT_SUPPORT <3>: PyConfig.
                                                             (line  869)
* environment variable; PYTHON_PERF_JIT_SUPPORT <4>: PyConfig.
                                                             (line  872)
* environment variable; PYTHON_PERF_JIT_SUPPORT <5>: How to work without frame pointers.
                                                             (line   14)
* environment variable; PYTHON_PRESITE:  Miscellaneous options.
                                                             (line  388)
* environment variable; PYTHON_PRESITE <1>: Debug-mode variables.
                                                             (line   25)
* environment variable; PYTHON_PRESITE <2>: PyConfig.        (line  770)
* environment variable; PYTHON_PRESITE=package.module: Core and Builtins<34>.
                                                             (line  154)
* environment variable; PYTHONASYNCIODEBUG: Environment variables.
                                                             (line  276)
* environment variable; PYTHONASYNCIODEBUG <1>: Enabling debug mode.
                                                             (line   10)
* environment variable; PYTHONASYNCIODEBUG <2>: Debug Mode.  (line   11)
* environment variable; PYTHONASYNCIODEBUG <3>: Effects of the Python Development Mode.
                                                             (line   65)
* environment variable; PYTHONBREAKPOINT: PEP 553 Built-in breakpoint.
                                                             (line   13)
* environment variable; PYTHONBREAKPOINT <1>: Environment variables.
                                                             (line   80)
* environment variable; PYTHONBREAKPOINT <2>: Built-in Functions.
                                                             (line  161)
* environment variable; PYTHONBREAKPOINT <3>: sys — System-specific parameters and functions.
                                                             (line  256)
* environment variable; PYTHONBREAKPOINT <4>: sys — System-specific parameters and functions.
                                                             (line  270)
* environment variable; PYTHONBREAKPOINT <5>: sys — System-specific parameters and functions.
                                                             (line  274)
* environment variable; PYTHONCASEOK:    Changes in the Python API<4>.
                                                             (line   29)
* environment variable; PYTHONCASEOK <1>: PEP 235 Importing Modules on Case-Insensitive Platforms.
                                                             (line   17)
* environment variable; PYTHONCASEOK <2>: Library<129>.      (line  144)
* environment variable; PYTHONCASEOK <3>: Environment variables.
                                                             (line  130)
* environment variable; PYTHONCASEOK <4>: Built-in Functions.
                                                             (line 2238)
* environment variable; PYTHONCOERCECLOCALE: PEP 538 Legacy C Locale Coercion.
                                                             (line   13)
* environment variable; PYTHONCOERCECLOCALE <1>: Environment variables.
                                                             (line  364)
* environment variable; PYTHONCOERCECLOCALE <2>: General Options.
                                                             (line   88)
* environment variable; PYTHONCOERCECLOCALE <3>: Python UTF-8 Mode.
                                                             (line   56)
* environment variable; PYTHONCOERCECLOCALE <4>: Python Configuration.
                                                             (line   15)
* environment variable; PYTHONDEBUG:     Miscellaneous options.
                                                             (line   37)
* environment variable; PYTHONDEBUG <1>: Environment variables.
                                                             (line   93)
* environment variable; PYTHONDEBUG <2>: Python Debug Build. (line   20)
* environment variable; PYTHONDEBUG <3>: Global configuration variables.
                                                             (line   38)
* environment variable; PYTHONDEBUG <4>: PyConfig.           (line  661)
* environment variable; PYTHONDEVMODE:   Python Development Mode -X dev.
                                                             (line    6)
* environment variable; PYTHONDEVMODE <1>: Miscellaneous options.
                                                             (line  306)
* environment variable; PYTHONDEVMODE <2>: Environment variables.
                                                             (line  420)
* environment variable; PYTHONDEVMODE <3>: Python Development Mode.
                                                             (line   14)
* environment variable; PYTHONDEVMODE <4>: PyConfig.         (line  292)
* environment variable; PYTHONDONTWRITEBYTECODE: Interpreter Changes<2>.
                                                             (line   16)
* environment variable; PYTHONDONTWRITEBYTECODE <1>: New and Improved Modules<2>.
                                                             (line  626)
* environment variable; PYTHONDONTWRITEBYTECODE <2>: Miscellaneous options.
                                                             (line   19)
* environment variable; PYTHONDONTWRITEBYTECODE <3>: Environment variables.
                                                             (line  135)
* environment variable; PYTHONDONTWRITEBYTECODE <4>: sys — System-specific parameters and functions.
                                                             (line  340)
* environment variable; PYTHONDONTWRITEBYTECODE <5>: Global configuration variables.
                                                             (line   52)
* environment variable; PYTHONDONTWRITEBYTECODE <6>: PyConfig.
                                                             (line  946)
* environment variable; PYTHONDONTWRITEBYTECODE <7>: How do I create a pyc file?.
                                                             (line   21)
* environment variable; PYTHONDUMPREFS:  Debug build uses the same ABI as release build.
                                                             (line   15)
* environment variable; PYTHONDUMPREFS <1>: Build<58>.       (line   54)
* environment variable; PYTHONDUMPREFS <2>: Debug-mode variables.
                                                             (line    6)
* environment variable; PYTHONDUMPREFS <3>: Debug options.   (line   22)
* environment variable; PYTHONDUMPREFS <4>: Debug options.   (line   24)
* environment variable; PYTHONDUMPREFS <5>: PyConfig.        (line  303)
* environment variable; PYTHONDUMPREFSFILE: Core and Builtins<86>.
                                                             (line   16)
* environment variable; PYTHONDUMPREFSFILE <1>: Debug-mode variables.
                                                             (line   14)
* environment variable; PYTHONEXECUTABLE: Environment variables.
                                                             (line  216)
* environment variable; PYTHONEXECUTABLE <1>: PyConfig.      (line  696)
* environment variable; PYTHONFAULTHANDLER: faulthandler<4>. (line   12)
* environment variable; PYTHONFAULTHANDLER <1>: Miscellaneous options.
                                                             (line  268)
* environment variable; PYTHONFAULTHANDLER <2>: Environment variables.
                                                             (line  244)
* environment variable; PYTHONFAULTHANDLER <3>: Effects of the Python Development Mode.
                                                             (line   59)
* environment variable; PYTHONFAULTHANDLER <4>: faulthandler — Dump the Python traceback.
                                                             (line   15)
* environment variable; PYTHONFAULTHANDLER <5>: PyConfig.    (line  341)
* environment variable; PYTHONHASHSEED:  Builtin functions and types.
                                                             (line   17)
* environment variable; PYTHONHASHSEED <1>: Porting Python code.
                                                             (line    6)
* environment variable; PYTHONHASHSEED <2>: Core and Builtins<143>.
                                                             (line   30)
* environment variable; PYTHONHASHSEED <3>: Miscellaneous options.
                                                             (line  130)
* environment variable; PYTHONHASHSEED <4>: Miscellaneous options.
                                                             (line  147)
* environment variable; PYTHONHASHSEED <5>: Environment variables.
                                                             (line  150)
* environment variable; PYTHONHASHSEED <6>: Environment variables.
                                                             (line  155)
* environment variable; PYTHONHASHSEED <7>: Basic customization.
                                                             (line  311)
* environment variable; PYTHONHASHSEED <8>: Global configuration variables.
                                                             (line   77)
* environment variable; PYTHONHASHSEED <9>: Global configuration variables.
                                                             (line   80)
* environment variable; PYTHONHASHSEED <10>: PyConfig.       (line  411)
* environment variable; PYTHONHOME:      Deprecated C APIs.  (line   26)
* environment variable; PYTHONHOME <1>:  Pending Removal in Python 3 15<2>.
                                                             (line   36)
* environment variable; PYTHONHOME <2>:  Pending Removal in Python 3 15<4>.
                                                             (line   36)
* environment variable; PYTHONHOME <3>:  Summary – Release highlights<6>.
                                                             (line  107)
* environment variable; PYTHONHOME <4>:  Miscellaneous options.
                                                             (line   46)
* environment variable; PYTHONHOME <5>:  Environment variables.
                                                             (line   11)
* environment variable; PYTHONHOME <6>:  Environment variables.
                                                             (line   19)
* environment variable; PYTHONHOME <7>:  Environment variables.
                                                             (line   21)
* environment variable; PYTHONHOME <8>:  Environment variables.
                                                             (line   37)
* environment variable; PYTHONHOME <9>:  Finding modules.    (line   29)
* environment variable; PYTHONHOME <10>: Finding modules.    (line   47)
* environment variable; PYTHONHOME <11>: Finding modules.    (line   81)
* environment variable; PYTHONHOME <12>: Adding Python to an iOS project.
                                                             (line  149)
* environment variable; PYTHONHOME <13>: test support script_helper — Utilities for the Python execution tests.
                                                             (line   25)
* environment variable; PYTHONHOME <14>: The initialization of the sys path module search path.
                                                             (line   30)
* environment variable; PYTHONHOME <15>: Virtual environments<2>.
                                                             (line   14)
* environment variable; PYTHONHOME <16>: Embedding Python<2>.
                                                             (line   38)
* environment variable; PYTHONHOME <17>: Embedding Python<2>.
                                                             (line   44)
* environment variable; PYTHONHOME <18>: Global configuration variables.
                                                             (line   92)
* environment variable; PYTHONHOME <19>: Process-wide parameters.
                                                             (line  295)
* environment variable; PYTHONHOME <20>: Process-wide parameters.
                                                             (line  311)
* environment variable; PYTHONHOME <21>: Process-wide parameters.
                                                             (line  320)
* environment variable; PYTHONHOME <22>: PyConfig.           (line  419)
* environment variable; PYTHONHOME <23>: PyConfig.           (line  421)
* environment variable; PYTHONHOME <24>: Pending Removal in Python 3 15<6>.
                                                             (line   36)
* environment variable; PYTHONINSPECT:   Other Changes and Fixes<2>.
                                                             (line   13)
* environment variable; PYTHONINSPECT <1>: Core and Builtins<2>.
                                                             (line   47)
* environment variable; PYTHONINSPECT <2>: Miscellaneous options.
                                                             (line   68)
* environment variable; PYTHONINSPECT <3>: Environment variables.
                                                             (line  102)
* environment variable; PYTHONINSPECT <4>: Global configuration variables.
                                                             (line  109)
* environment variable; PYTHONINSPECT <5>: PyConfig.         (line  446)
* environment variable; PYTHONINTMAXSTRDIGITS: Core and Builtins<52>.
                                                             (line   74)
* environment variable; PYTHONINTMAXSTRDIGITS <1>: Miscellaneous options.
                                                             (line  290)
* environment variable; PYTHONINTMAXSTRDIGITS <2>: Environment variables.
                                                             (line  168)
* environment variable; PYTHONINTMAXSTRDIGITS <3>: Configuring the limit.
                                                             (line    9)
* environment variable; PYTHONINTMAXSTRDIGITS <4>: Configuring the limit.
                                                             (line   16)
* environment variable; PYTHONINTMAXSTRDIGITS <5>: sys — System-specific parameters and functions.
                                                             (line 1164)
* environment variable; PYTHONINTMAXSTRDIGITS <6>: PyConfig. (line  477)
* environment variable; PYTHONIOENCODING: Other Improvements<2>.
                                                             (line   75)
* environment variable; PYTHONIOENCODING <1>: Interpreter Changes<2>.
                                                             (line   23)
* environment variable; PYTHONIOENCODING <2>: Environment variables.
                                                             (line  176)
* environment variable; PYTHONIOENCODING <3>: Environment variables.
                                                             (line  401)
* environment variable; PYTHONIOENCODING <4>: Python UTF-8 Mode.
                                                             (line   28)
* environment variable; PYTHONIOENCODING <5>: sys — System-specific parameters and functions.
                                                             (line 1848)
* environment variable; PYTHONIOENCODING <6>: PyConfig.      (line  829)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING: New Deprecations.
                                                             (line  131)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <1>: Pending removal in Python 3 16.
                                                             (line   50)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <2>: Pending removal in Python 3 16<3>.
                                                             (line   50)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <3>: PEP 529 Change Windows filesystem encoding to UTF-8.
                                                             (line   18)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <4>: Windows<17>.
                                                             (line   37)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <5>: Environment variables.
                                                             (line  337)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <6>: sys — System-specific parameters and functions.
                                                             (line 1788)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <7>: sys — System-specific parameters and functions.
                                                             (line 1799)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <8>: sys — System-specific parameters and functions.
                                                             (line 1805)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <9>: Global configuration variables.
                                                             (line  151)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <10>: PyPreConfig.
                                                             (line  123)
* environment variable; PYTHONLEGACYWINDOWSFSENCODING <11>: Pending removal in Python 3 16<5>.
                                                             (line   50)
* environment variable; PYTHONLEGACYWINDOWSSTDIO: PEP 528 Change Windows console encoding to UTF-8.
                                                             (line   12)
* environment variable; PYTHONLEGACYWINDOWSSTDIO <1>: Environment variables.
                                                             (line  190)
* environment variable; PYTHONLEGACYWINDOWSSTDIO <2>: Environment variables.
                                                             (line  351)
* environment variable; PYTHONLEGACYWINDOWSSTDIO <3>: sys — System-specific parameters and functions.
                                                             (line 1852)
* environment variable; PYTHONLEGACYWINDOWSSTDIO <4>: Global configuration variables.
                                                             (line  169)
* environment variable; PYTHONLEGACYWINDOWSSTDIO <5>: PyConfig.
                                                             (line  530)
* environment variable; PYTHONMALLOC:    PYTHONMALLOC environment variable.
                                                             (line    6)
* environment variable; PYTHONMALLOC <1>: Changes in the C API<6>.
                                                             (line    9)
* environment variable; PYTHONMALLOC <2>: Core and Builtins<163>.
                                                             (line   90)
* environment variable; PYTHONMALLOC <3>: Environment variables.
                                                             (line  283)
* environment variable; PYTHONMALLOC <4>: Environment variables.
                                                             (line  328)
* environment variable; PYTHONMALLOC <5>: Performance options.
                                                             (line  109)
* environment variable; PYTHONMALLOC <6>: Performance options.
                                                             (line  116)
* environment variable; PYTHONMALLOC <7>: Effects of the Python Development Mode.
                                                             (line   46)
* environment variable; PYTHONMALLOC <8>: Effects of the Python Development Mode.
                                                             (line   50)
* environment variable; PYTHONMALLOC <9>: Overview<4>.       (line   75)
* environment variable; PYTHONMALLOC <10>: Default Memory Allocators.
                                                             (line   26)
* environment variable; PYTHONMALLOC <11>: Debug hooks on the Python memory allocators.
                                                             (line   11)
* environment variable; PYTHONMALLOC <12>: The pymalloc allocator.
                                                             (line   27)
* environment variable; PYTHONMALLOCSTATS: Core and Builtins<163>.
                                                             (line   96)
* environment variable; PYTHONMALLOCSTATS <1>: Environment variables.
                                                             (line  322)
* environment variable; PYTHONMALLOCSTATS <2>: PyConfig.     (line  546)
* environment variable; PYTHONMALLOCSTATS <3>: Overview<4>.  (line   78)
* environment variable; PYTHONNODEBUGRANGES: PEP 657 Fine-grained error locations in tracebacks.
                                                             (line   63)
* environment variable; PYTHONNODEBUGRANGES <1>: Miscellaneous options.
                                                             (line  335)
* environment variable; PYTHONNODEBUGRANGES <2>: Environment variables.
                                                             (line  450)
* environment variable; PYTHONNODEBUGRANGES <3>: Methods on code objects.
                                                             (line   40)
* environment variable; PYTHONNODEBUGRANGES <4>: PyConfig.   (line  245)
* environment variable; PYTHONNOUSERSITE: PEP 370 Per-user site-packages Directory.
                                                             (line   30)
* environment variable; PYTHONNOUSERSITE <1>: Miscellaneous options.
                                                             (line  159)
* environment variable; PYTHONNOUSERSITE <2>: Environment variables.
                                                             (line  194)
* environment variable; PYTHONNOUSERSITE <3>: Module contents<6>.
                                                             (line   15)
* environment variable; PYTHONNOUSERSITE <4>: Global configuration variables.
                                                             (line  203)
* environment variable; PYTHONNOUSERSITE <5>: PyConfig.      (line  899)
* environment variable; PYTHONOPTIMIZE:  Miscellaneous options.
                                                             (line   88)
* environment variable; PYTHONOPTIMIZE <1>: Environment variables.
                                                             (line   74)
* environment variable; PYTHONOPTIMIZE <2>: Global configuration variables.
                                                             (line  214)
* environment variable; PYTHONOPTIMIZE <3>: PyConfig.        (line  613)
* environment variable; PYTHONPATH:      Changes in ‘python’ Command Behavior<2>.
                                                             (line    8)
* environment variable; PYTHONPATH <1>:  Changes in ‘python’ Command Behavior<2>.
                                                             (line    9)
* environment variable; PYTHONPATH <2>:  The Module Search Path.
                                                             (line   16)
* environment variable; PYTHONPATH <3>:  Standard Modules.   (line   34)
* environment variable; PYTHONPATH <4>:  Standard Modules.   (line   35)
* environment variable; PYTHONPATH <5>:  Miscellaneous options.
                                                             (line   45)
* environment variable; PYTHONPATH <6>:  Environment variables.
                                                             (line   23)
* environment variable; PYTHONPATH <7>:  Environment variables.
                                                             (line   31)
* environment variable; PYTHONPATH <8>:  Environment variables.
                                                             (line   38)
* environment variable; PYTHONPATH <9>:  Environment variables.
                                                             (line   41)
* environment variable; PYTHONPATH <10>: Excursus Setting environment variables.
                                                             (line   38)
* environment variable; PYTHONPATH <11>: Finding modules.    (line   15)
* environment variable; PYTHONPATH <12>: Finding modules.    (line   38)
* environment variable; PYTHONPATH <13>: Finding modules.    (line   81)
* environment variable; PYTHONPATH <14>: Adding Python to an iOS project.
                                                             (line  152)
* environment variable; PYTHONPATH <15>: Adding Python to an iOS project.
                                                             (line  183)
* environment variable; PYTHONPATH <16>: Adding Python to an iOS project.
                                                             (line  189)
* environment variable; PYTHONPATH <17>: Path entry finders. (line   23)
* environment variable; PYTHONPATH <18>: test support script_helper — Utilities for the Python execution tests.
                                                             (line   26)
* environment variable; PYTHONPATH <19>: sys — System-specific parameters and functions.
                                                             (line 1330)
* environment variable; PYTHONPATH <20>: sys — System-specific parameters and functions.
                                                             (line 1335)
* environment variable; PYTHONPATH <21>: The initialization of the sys path module search path.
                                                             (line   14)
* environment variable; PYTHONPATH <22>: The initialization of the sys path module search path.
                                                             (line   18)
* environment variable; PYTHONPATH <23>: Building C and C++ Extensions.
                                                             (line    9)
* environment variable; PYTHONPATH <24>: Embedding Python<2>.
                                                             (line   39)
* environment variable; PYTHONPATH <25>: Embedding Python<2>.
                                                             (line   45)
* environment variable; PYTHONPATH <26>: Global configuration variables.
                                                             (line   91)
* environment variable; PYTHONPATH <27>: PyConfig.           (line  579)
* environment variable; PYTHONPERFSUPPORT: Other Language Changes<2>.
                                                             (line   84)
* environment variable; PYTHONPERFSUPPORT <1>: Miscellaneous options.
                                                             (line  355)
* environment variable; PYTHONPERFSUPPORT <2>: Environment variables.
                                                             (line  461)
* environment variable; PYTHONPERFSUPPORT <3>: How to enable perf profiling support.
                                                             (line    7)
* environment variable; PYTHONPLATLIBDIR: Core and Builtins<122>.
                                                             (line   47)
* environment variable; PYTHONPLATLIBDIR <1>: Environment variables.
                                                             (line   53)
* environment variable; PYTHONPLATLIBDIR <2>: The initialization of the sys path module search path.
                                                             (line   51)
* environment variable; PYTHONPLATLIBDIR <3>: PyConfig.      (line  558)
* environment variable; PYTHONPROFILEIMPORTTIME: Other Language Changes<7>.
                                                             (line   47)
* environment variable; PYTHONPROFILEIMPORTTIME <1>: Core and Builtins<145>.
                                                             (line   66)
* environment variable; PYTHONPROFILEIMPORTTIME <2>: Miscellaneous options.
                                                             (line  299)
* environment variable; PYTHONPROFILEIMPORTTIME <3>: Environment variables.
                                                             (line  268)
* environment variable; PYTHONPROFILEIMPORTTIME <4>: PyConfig.
                                                             (line  431)
* environment variable; PYTHONPYCACHEPREFIX: Parallel filesystem cache for compiled bytecode files.
                                                             (line    6)
* environment variable; PYTHONPYCACHEPREFIX <1>: Core and Builtins<136>.
                                                             (line  402)
* environment variable; PYTHONPYCACHEPREFIX <2>: Miscellaneous options.
                                                             (line  319)
* environment variable; PYTHONPYCACHEPREFIX <3>: Environment variables.
                                                             (line  141)
* environment variable; PYTHONPYCACHEPREFIX <4>: sys — System-specific parameters and functions.
                                                             (line  386)
* environment variable; PYTHONPYCACHEPREFIX <5>: PyConfig.   (line  718)
* environment variable; PYTHONREGRTEST_UNICODE_GUARD: Tests<30>.
                                                             (line   13)
* environment variable; PYTHONSAFEPATH:  Summary – Release highlights<2>.
                                                             (line   27)
* environment variable; PYTHONSAFEPATH <1>: Other Language Changes<3>.
                                                             (line   37)
* environment variable; PYTHONSAFEPATH <2>: Security<25>.    (line    6)
* environment variable; PYTHONSAFEPATH <3>: Miscellaneous options.
                                                             (line  116)
* environment variable; PYTHONSAFEPATH <4>: Environment variables.
                                                             (line   45)
* environment variable; PYTHONSAFEPATH <5>: sys — System-specific parameters and functions.
                                                             (line 1347)
* environment variable; PYTHONSAFEPATH <6>: Security Considerations<3>.
                                                             (line   47)
* environment variable; PYTHONSAFEPATH <7>: PyConfig.        (line  162)
* environment variable; PYTHONSTARTUP:   sys<12>.            (line   17)
* environment variable; PYTHONSTARTUP <1>: sys<12>.          (line   21)
* environment variable; PYTHONSTARTUP <2>: Library<2>.       (line  116)
* environment variable; PYTHONSTARTUP <3>: Core and Builtins<5>.
                                                             (line   24)
* environment variable; PYTHONSTARTUP <4>: IDLE<41>.         (line  176)
* environment variable; PYTHONSTARTUP <5>: IDLE<45>.         (line    9)
* environment variable; PYTHONSTARTUP <6>: IDLE<51>.         (line    9)
* environment variable; PYTHONSTARTUP <7>: The Interactive Startup File.
                                                             (line    8)
* environment variable; PYTHONSTARTUP <8>: Miscellaneous options.
                                                             (line   64)
* environment variable; PYTHONSTARTUP <9>: Environment variables.
                                                             (line   60)
* environment variable; PYTHONSTARTUP <10>: Environment variables.
                                                             (line  116)
* environment variable; PYTHONSTARTUP <11>: Example.         (line   10)
* environment variable; PYTHONSTARTUP <12>: asyncio — Asynchronous I/O.
                                                             (line   91)
* environment variable; PYTHONSTARTUP <13>: Startup and Code Execution.
                                                             (line    7)
* environment variable; PYTHONSTARTUP <14>: Command-line usage<3>.
                                                             (line   42)
* environment variable; PYTHONSTARTUP <15>: sys — System-specific parameters and functions.
                                                             (line 1177)
* environment variable; PYTHONSTARTUP <16>: Readline configuration.
                                                             (line   12)
* environment variable; PYTHONTRACEMALLOC: Miscellaneous options.
                                                             (line  285)
* environment variable; PYTHONTRACEMALLOC <1>: Environment variables.
                                                             (line  255)
* environment variable; PYTHONTRACEMALLOC <2>: tracemalloc — Trace memory allocations.
                                                             (line   25)
* environment variable; PYTHONTRACEMALLOC <3>: tracemalloc — Trace memory allocations.
                                                             (line   32)
* environment variable; PYTHONTRACEMALLOC <4>: Functions<11>.
                                                             (line   89)
* environment variable; PYTHONTRACEMALLOC <5>: PyConfig.     (line  857)
* environment variable; PYTHONTZPATH:    Environment configuration.
                                                             (line   11)
* environment variable; PYTHONTZPATH <1>: Exceptions and warnings.
                                                             (line   14)
* environment variable; PYTHONUNBUFFERED: Core and Builtins<129>.
                                                             (line  107)
* environment variable; PYTHONUNBUFFERED <1>: Miscellaneous options.
                                                             (line  179)
* environment variable; PYTHONUNBUFFERED <2>: Environment variables.
                                                             (line  119)
* environment variable; PYTHONUNBUFFERED <3>: sys — System-specific parameters and functions.
                                                             (line 1859)
* environment variable; PYTHONUNBUFFERED <4>: Global configuration variables.
                                                             (line  242)
* environment variable; PYTHONUNBUFFERED <5>: PyConfig.      (line  209)
* environment variable; PYTHONUOPS:      Core and Builtins<35>.
                                                             (line   27)
* environment variable; PYTHONUOPS <1>:  Core and Builtins<35>.
                                                             (line  179)
* environment variable; PYTHONUOPS <2>:  Core and Builtins<35>.
                                                             (line  258)
* environment variable; PYTHONUOPS <3>:  Core and Builtins<35>.
                                                             (line  317)
* environment variable; PYTHONUOPS <4>:  Core and Builtins<35>.
                                                             (line  381)
* environment variable; PYTHONUSERBASE:  PEP 370 Per-user site-packages Directory.
                                                             (line   23)
* environment variable; PYTHONUSERBASE <1>: Environment variables.
                                                             (line  204)
* environment variable; PYTHONUSERBASE <2>: Module contents<6>.
                                                             (line   40)
* environment variable; PYTHONUSERBASE <3>: Module contents<6>.
                                                             (line   68)
* environment variable; PYTHONUSERSITE:  test support script_helper — Utilities for the Python execution tests.
                                                             (line   26)
* environment variable; PYTHONUTF8:      PEP 540 Forced UTF-8 Runtime Mode.
                                                             (line    6)
* environment variable; PYTHONUTF8 <1>:  Miscellaneous options.
                                                             (line  313)
* environment variable; PYTHONUTF8 <2>:  Environment variables.
                                                             (line  411)
* environment variable; PYTHONUTF8 <3>:  Environment variables.
                                                             (line  429)
* environment variable; PYTHONUTF8 <4>:  UTF-8 mode.         (line   18)
* environment variable; PYTHONUTF8 <5>:  Python UTF-8 Mode.  (line   51)
* environment variable; PYTHONUTF8 <6>:  Python UTF-8 Mode.  (line   53)
* environment variable; PYTHONUTF8 <7>:  sys — System-specific parameters and functions.
                                                             (line 1850)
* environment variable; PYTHONUTF8 <8>:  PyPreConfig.        (line  152)
* environment variable; PYTHONUTF8 <9>:  Python Configuration.
                                                             (line   14)
* environment variable; PYTHONVERBOSE:   Miscellaneous options.
                                                             (line  195)
* environment variable; PYTHONVERBOSE <1>: Environment variables.
                                                             (line  124)
* environment variable; PYTHONVERBOSE <2>: Global configuration variables.
                                                             (line  259)
* environment variable; PYTHONVERBOSE <3>: PyConfig.         (line  916)
* environment variable; PYTHONWARNDEFAULTENCODING: Optional EncodingWarning and encoding="locale" option.
                                                             (line   19)
* environment variable; PYTHONWARNDEFAULTENCODING <1>: Library<97>.
                                                             (line   45)
* environment variable; PYTHONWARNDEFAULTENCODING <2>: Miscellaneous options.
                                                             (line  325)
* environment variable; PYTHONWARNDEFAULTENCODING <3>: Environment variables.
                                                             (line  440)
* environment variable; PYTHONWARNDEFAULTENCODING <4>: Opt-in EncodingWarning.
                                                             (line    9)
* environment variable; PYTHONWARNINGS:  warnings<3>.        (line   21)
* environment variable; PYTHONWARNINGS <1>: Other Language Changes<12>.
                                                             (line  159)
* environment variable; PYTHONWARNINGS <2>: Changes to the Handling of Deprecation Warnings.
                                                             (line   25)
* environment variable; PYTHONWARNINGS <3>: Interpreter Changes.
                                                             (line    6)
* environment variable; PYTHONWARNINGS <4>: Documentation<26>.
                                                             (line   67)
* environment variable; PYTHONWARNINGS <5>: Miscellaneous options.
                                                             (line  249)
* environment variable; PYTHONWARNINGS <6>: Environment variables.
                                                             (line  222)
* environment variable; PYTHONWARNINGS <7>: Effects of the Python Development Mode.
                                                             (line   30)
* environment variable; PYTHONWARNINGS <8>: The Warnings Filter.
                                                             (line   46)
* environment variable; PYTHONWARNINGS <9>: The Warnings Filter.
                                                             (line   56)
* environment variable; PYTHONWARNINGS <10>: Describing Warning Filters.
                                                             (line    7)
* environment variable; PYTHONWARNINGS <11>: Describing Warning Filters.
                                                             (line   21)
* environment variable; PYTHONWARNINGS <12>: Default Warning Filter.
                                                             (line    7)
* environment variable; PYTHONWARNINGS <13>: PyConfig.       (line  935)
* environment variable; SOURCE_DATE_EPOCH: py_compile<3>.    (line    7)
* environment variable; SOURCE_DATE_EPOCH <1>: Library<138>. (line  451)
* environment variable; SOURCE_DATE_EPOCH <2>: Build<66>.    (line   15)
* environment variable; SOURCE_DATE_EPOCH <3>: py_compile — Compile Python source files.
                                                             (line   66)
* environment variable; SOURCE_DATE_EPOCH <4>: py_compile — Compile Python source files.
                                                             (line   82)
* environment variable; SOURCE_DATE_EPOCH <5>: py_compile — Compile Python source files.
                                                             (line   86)
* environment variable; SOURCE_DATE_EPOCH <6>: Command-line use.
                                                             (line   97)
* environment variable; SSLKEYLOGFILE:   Context creation.   (line   34)
* environment variable; SSLKEYLOGFILE <1>: Context creation. (line   83)
* environment variable; TEMP:            Redirection of local data registry and temporary paths.
                                                             (line    7)
* environment variable; TEMP <1>:        tempfile — Generate temporary files and directories.
                                                             (line  329)
* environment variable; TERM:            Functions<6>.       (line  484)
* environment variable; TERM <1>:        Functions<6>.       (line  510)
* environment variable; TMP:             tempfile — Generate temporary files and directories.
                                                             (line  331)
* environment variable; TMPDIR:          Library<8>.         (line  116)
* environment variable; TMPDIR <1>:      Tests<29>.          (line   68)
* environment variable; TMPDIR <2>:      tempfile — Generate temporary files and directories.
                                                             (line  327)
* environment variable; TZ:              Functions<5>.       (line  641)
* environment variable; TZ <1>:          Functions<5>.       (line  642)
* environment variable; TZ <2>:          Functions<5>.       (line  650)
* environment variable; TZ <3>:          Functions<5>.       (line  655)
* environment variable; TZ <4>:          Functions<5>.       (line  657)
* environment variable; TZ <5>:          Functions<5>.       (line  718)
* environment variable; USER:            getpass — Portable password input.
                                                             (line   43)
* environment variable; USERNAME:        os path — Common pathname manipulations.
                                                             (line  152)
* environment variable; USERNAME <1>:    Process Parameters. (line  234)
* environment variable; USERNAME <2>:    getpass — Portable password input.
                                                             (line   44)
* environment variable; USERPROFILE:     os path<5>.         (line   14)
* environment variable; USERPROFILE <1>: Changes in the Python API<5>.
                                                             (line  117)
* environment variable; USERPROFILE <2>: Windows<46>.        (line   15)
* environment variable; USERPROFILE <3>: os path — Common pathname manipulations.
                                                             (line  149)
* environment variables; deleting:       Process Parameters. (line  579)
* environment variables; setting:        Process Parameters. (line  348)
* EnvironmentError:                      Concrete exceptions.
                                                             (line  495)
* Environments; virtual:                 venv — Creation of virtual environments.
                                                             (line   10)
* EnvironmentVarGuard (class in test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   48)
* ENXIO (in module errno):               errno — Standard errno system symbols.
                                                             (line   50)
* eof (bz2.BZ2Decompressor attribute):   Incremental de compression.
                                                             (line   72)
* eof (lzma.LZMADecompressor attribute): Compressing and decompressing data in memory.
                                                             (line  163)
* eof (shlex.shlex attribute):           shlex Objects.      (line  178)
* eof (ssl.MemoryBIO attribute):         Memory BIO support. (line  143)
* eof (zlib.Decompress attribute):       zlib — Compression compatible with gzip.
                                                             (line  252)
* eof_received() (asyncio.BufferedProtocol method): Buffered Streaming Protocols.
                                                             (line   40)
* eof_received() (asyncio.Protocol method): Streaming Protocols.
                                                             (line   30)
* EOFError:                              Concrete exceptions.
                                                             (line   33)
* EOFError (built-in exception):         File Objects.       (line   44)
* EOPNOTSUPP (in module errno):          errno — Standard errno system symbols.
                                                             (line  414)
* EOT (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   30)
* EOVERFLOW (in module errno):           errno — Standard errno system symbols.
                                                             (line  334)
* EOWNERDEAD (in module errno):          errno — Standard errno system symbols.
                                                             (line  698)
* EPERM (in module errno):               errno — Standard errno system symbols.
                                                             (line   26)
* EPFNOSUPPORT (in module errno):        errno — Standard errno system symbols.
                                                             (line  424)
* epilogue (email.message.EmailMessage attribute): email message Representing an email message.
                                                             (line  703)
* epilogue (email.message.Message attribute): email message Message Representing an email message using the compat32 API.
                                                             (line  715)
* EPIPE (in module errno):               errno — Standard errno system symbols.
                                                             (line  160)
* epoch:                                 time — Time access and conversions.
                                                             (line   20)
* epoll() (in module select):            select — Waiting for I/O completion.
                                                             (line   55)
* EpollSelector (class in selectors):    Classes<4>.         (line  175)
* EPROCLIM (in module errno):            errno — Standard errno system symbols.
                                                             (line  635)
* EPROCUNAVAIL (in module errno):        errno — Standard errno system symbols.
                                                             (line  641)
* EPROGMISMATCH (in module errno):       errno — Standard errno system symbols.
                                                             (line  647)
* EPROGUNAVAIL (in module errno):        errno — Standard errno system symbols.
                                                             (line  653)
* EPROTO (in module errno):              errno — Standard errno system symbols.
                                                             (line  318)
* EPROTONOSUPPORT (in module errno):     errno — Standard errno system symbols.
                                                             (line  406)
* EPROTOTYPE (in module errno):          errno — Standard errno system symbols.
                                                             (line  398)
* epsilon (sys.float_info attribute):    sys — System-specific parameters and functions.
                                                             (line  621)
* EPWROFF (in module errno):             errno — Standard errno system symbols.
                                                             (line  659)
* Eq (class in ast):                     Expressions<2>.     (line  108)
* eq() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* EQEQUAL (in module token):             token — Constants used with Python parse trees.
                                                             (line  236)
* EQFULL (in module errno):              errno — Standard errno system symbols.
                                                             (line  539)
* EQUAL (in module token):               token — Constants used with Python parse trees.
                                                             (line  221)
* ERA (in module locale):                locale — Internationalization services.
                                                             (line  312)
* ERA_D_FMT (in module locale):          locale — Internationalization services.
                                                             (line  334)
* ERA_D_T_FMT (in module locale):        locale — Internationalization services.
                                                             (line  329)
* ERA_T_FMT (in module locale):          locale — Internationalization services.
                                                             (line  339)
* ERANGE (in module errno):              errno — Standard errno system symbols.
                                                             (line  169)
* erase() (curses.window method):        Window Objects.     (line  222)
* erasechar() (in module curses):        Functions<6>.       (line  114)
* EREMCHG (in module errno):             errno — Standard errno system symbols.
                                                             (line  346)
* EREMOTE (in module errno):             errno — Standard errno system symbols.
                                                             (line  298)
* EREMOTEIO (in module errno):           errno — Standard errno system symbols.
                                                             (line  531)
* ERESTART (in module errno):            errno — Standard errno system symbols.
                                                             (line  374)
* erf() (in module math):                Special functions.  (line    6)
* erfc() (in module math):               Special functions.  (line   19)
* ERFKILL (in module errno):             errno — Standard errno system symbols.
                                                             (line  569)
* EROFS (in module errno):               errno — Standard errno system symbols.
                                                             (line  152)
* ERPCMISMATCH (in module errno):        errno — Standard errno system symbols.
                                                             (line  671)
* ERR (in module curses):                Constants<6>.       (line    8)
* errcheck (ctypes._CFuncPtr attribute): Foreign functions.  (line   69)
* errcode (xmlrpc.client.ProtocolError attribute): ProtocolError Objects.
                                                             (line   17)
* errmsg (xmlrpc.client.ProtocolError attribute): ProtocolError Objects.
                                                             (line   21)
* errno (OSError attribute):             Concrete exceptions.
                                                             (line  172)
* error:                                 Functions and Exceptions.
                                                             (line    8)
* Error:                                 copy — Shallow and deep copy operations.
                                                             (line   33)
* Error <1>:                             Directory and files operations.
                                                             (line  474)
* error <1>:                             dbm — Interfaces to Unix “databases”.
                                                             (line   22)
* error <2>:                             dbm gnu — GNU database manager.
                                                             (line   24)
* error <3>:                             dbm ndbm — New Database Manager.
                                                             (line   30)
* error <4>:                             dbm dumb — Portable DBM implementation.
                                                             (line   21)
* Error <2>:                             Exceptions<7>.      (line   15)
* error <5>:                             zlib — Compression compatible with gzip.
                                                             (line   24)
* Error <3>:                             Module Contents<2>. (line  335)
* Error <4>:                             Exceptions<8>.      (line    6)
* error <6>:                             os — Miscellaneous operating system interfaces.
                                                             (line   51)
* error <7>:                             Functions<6>.       (line    8)
* error <8>:                             _thread — Low-level threading API.
                                                             (line   21)
* error <9>:                             Exceptions<15>.     (line    6)
* error <10>:                            select — Waiting for I/O completion.
                                                             (line   29)
* Error <5>:                             Exceptions<18>.     (line    8)
* Error <6>:                             binascii — Convert between binary and ASCII.
                                                             (line  157)
* error <11>:                            xml parsers expat — Fast XML parsing using Expat.
                                                             (line   30)
* Error <7>:                             Command-line interface<4>.
                                                             (line   26)
* Error <8>:                             wave — Read and write WAV files.
                                                             (line   50)
* Error <9>:                             locale — Internationalization services.
                                                             (line   21)
* error <12>:                            resource — Resource usage information.
                                                             (line   19)
* error <13>:                            getopt — C-style parser for command line options.
                                                             (line   93)
* ERROR (in module logging):             Logging Levels.     (line   40)
* ERROR (in module tkinter.messagebox):  tkinter messagebox — Tkinter message prompts.
                                                             (line  192)
* error handling:                        Exceptions<2>.      (line    6)
* error_body (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  263)
* error_content_type (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  156)
* error_headers (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  256)
* error_leader() (shlex.shlex method):   shlex Objects.      (line   69)
* error_message_format (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  148)
* error_output() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  226)
* error_perm:                            Module variables.   (line   16)
* error_proto:                           Module variables.   (line   21)
* error_proto <1>:                       poplib — POP3 protocol client.
                                                             (line   88)
* error_received() (asyncio.DatagramProtocol method): Datagram Protocols.
                                                             (line   15)
* error_reply:                           Module variables.   (line    6)
* error_status (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  250)
* error_temp:                            Module variables.   (line   11)
* error() (argparse.ArgumentParser method): Exiting methods. (line   19)
* error() (in module logging):           Module-Level Functions.
                                                             (line   80)
* error() (logging.Logger method):       Logger Objects.     (line  302)
* error() (urllib.request.OpenerDirector method): OpenerDirector Objects.
                                                             (line   58)
* error() (xml.sax.handler.ErrorHandler method): ErrorHandler Objects.
                                                             (line   16)
* ErrorByteIndex (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  219)
* errorcode (in module errno):           errno — Standard errno system symbols.
                                                             (line   13)
* ErrorCode (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  223)
* ErrorColumnNumber (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  229)
* ErrorHandler (class in xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   38)
* errorlevel (tarfile.TarFile attribute): TarFile Objects.   (line  223)
* ErrorLineNumber (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  233)
* errors:                                Exceptions<2>.      (line    6)
* errors (io.TextIOBase attribute):      Text I/O<2>.        (line   20)
* errors (unittest.TestLoader attribute): Loading and running tests.
                                                             (line   17)
* errors (unittest.TestResult attribute): Loading and running tests.
                                                             (line  243)
* Errors; logging:                       logging — Logging facility for Python.
                                                             (line    8)
* ErrorStream (class in wsgiref.types):  wsgiref types – WSGI types for static type checking.
                                                             (line   28)
* ErrorString() (in module xml.parsers.expat): xml parsers expat — Fast XML parsing using Expat.
                                                             (line   41)
* ERRORTOKEN (in module token):          token — Constants used with Python parse trees.
                                                             (line  159)
* ESC (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line  105)
* escape (shlex.shlex attribute):        shlex Objects.      (line  110)
* escape sequence:                       String and Bytes literals.
                                                             (line   74)
* escape() (in module glob):             glob — Unix style pathname pattern expansion.
                                                             (line  102)
* escape() (in module html):             html — HyperText Markup Language support.
                                                             (line   12)
* escape() (in module re):               Functions<2>.       (line  256)
* escape() (in module xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   14)
* escapechar (csv.Dialect attribute):    Dialects and Formatting Parameters.
                                                             (line   34)
* escapedquotes (shlex.shlex attribute): shlex Objects.      (line  122)
* ESHLIBVERS (in module errno):          errno — Standard errno system symbols.
                                                             (line  677)
* ESHUTDOWN (in module errno):           errno — Standard errno system symbols.
                                                             (line  474)
* esmtp_features (smtplib.SMTP attribute): SMTP Objects.     (line  365)
* ESOCKTNOSUPPORT (in module errno):     errno — Standard errno system symbols.
                                                             (line  410)
* ESPIPE (in module errno):              errno — Standard errno system symbols.
                                                             (line  148)
* ESRCH (in module errno):               errno — Standard errno system symbols.
                                                             (line   36)
* ESRMNT (in module errno):              errno — Standard errno system symbols.
                                                             (line  310)
* ESTALE (in module errno):              errno — Standard errno system symbols.
                                                             (line  511)
* ESTRPIPE (in module errno):            errno — Standard errno system symbols.
                                                             (line  378)
* ETB (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   93)
* ETH_P_ALL (in module socket):          Constants<8>.       (line  222)
* ETHERTYPE_ARP (in module socket):      Constants<8>.       (line  364)
* ETHERTYPE_IP (in module socket):       Constants<8>.       (line  364)
* ETHERTYPE_IPV6 (in module socket):     Constants<8>.       (line  364)
* ETHERTYPE_VLAN (in module socket):     Constants<8>.       (line  364)
* ETIME (in module errno):               errno — Standard errno system symbols.
                                                             (line  282)
* ETIMEDOUT (in module errno):           errno — Standard errno system symbols.
                                                             (line  483)
* Etiny() (decimal.Context method):      Context objects.    (line  244)
* ETOOMANYREFS (in module errno):        errno — Standard errno system symbols.
                                                             (line  479)
* Etop() (decimal.Context method):       Context objects.    (line  250)
* ETX (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   27)
* ETXTBSY (in module errno):             errno — Standard errno system symbols.
                                                             (line  136)
* EUCLEAN (in module errno):             errno — Standard errno system symbols.
                                                             (line  515)
* EUNATCH (in module errno):             errno — Standard errno system symbols.
                                                             (line  230)
* EUSERS (in module errno):              errno — Standard errno system symbols.
                                                             (line  382)
* evaluation; order:                     Evaluation order.   (line    6)
* Event (class in asyncio):              Event.              (line    6)
* Event (class in multiprocessing):      Synchronization primitives.
                                                             (line   51)
* Event (class in threading):            Event objects.      (line   14)
* event scheduling:                      sched — Event scheduler.
                                                             (line    8)
* EVENT_READ (in module selectors):      Classes<4>.         (line   23)
* EVENT_WRITE (in module selectors):     Classes<4>.         (line   26)
* Event() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  183)
* eventfd_read() (in module os):         Files and Directories.
                                                             (line 1894)
* eventfd_write() (in module os):        Files and Directories.
                                                             (line 1904)
* eventfd() (in module os):              Files and Directories.
                                                             (line 1841)
* EventLoop (class in asyncio):          Event loop implementations.
                                                             (line   44)
* events (selectors.SelectorKey attribute): Classes<4>.      (line   44)
* events (widgets):                      Bindings and Events.
                                                             (line    6)
* EWOULDBLOCK (in module errno):         errno — Standard errno system symbols.
                                                             (line  197)
* EX_CANTCREAT (in module os):           Process Management. (line  204)
* EX_CONFIG (in module os):              Process Management. (line  240)
* EX_DATAERR (in module os):             Process Management. (line  153)
* EX_IOERR (in module os):               Process Management. (line  211)
* EX_NOHOST (in module os):              Process Management. (line  172)
* EX_NOINPUT (in module os):             Process Management. (line  159)
* EX_NOPERM (in module os):              Process Management. (line  233)
* EX_NOTFOUND (in module os):            Process Management. (line  247)
* EX_NOUSER (in module os):              Process Management. (line  166)
* EX_OK (in module os):                  Process Management. (line  138)
* EX_OSERR (in module os):               Process Management. (line  190)
* EX_OSFILE (in module os):              Process Management. (line  197)
* EX_PROTOCOL (in module os):            Process Management. (line  226)
* EX_SOFTWARE (in module os):            Process Management. (line  184)
* EX_TEMPFAIL (in module os):            Process Management. (line  218)
* EX_UNAVAILABLE (in module os):         Process Management. (line  178)
* EX_USAGE (in module os):               Process Management. (line  146)
* EXACT_TOKEN_TYPES (in module token):   token — Constants used with Python parse trees.
                                                             (line  326)
* Example (class in doctest):            Example Objects.    (line    6)
* example (doctest.DocTestFailure attribute): Debugging.     (line  200)
* example (doctest.UnexpectedException attribute): Debugging.
                                                             (line  221)
* examples (doctest.DocTest attribute):  DocTest Objects.    (line   16)
* exc_info (doctest.UnexpectedException attribute): Debugging.
                                                             (line  225)
* exc_info (in module sys):              Traceback objects.  (line    6)
* exc_info (in module sys) <1>:          Exceptions<21>.     (line   45)
* exc_info() (in module sys):            sys — System-specific parameters and functions.
                                                             (line  448)
* exc_msg (doctest.Example attribute):   Example Objects.    (line   30)
* exc_type (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   79)
* exc_type_str (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   85)
* excel (class in csv):                  Module Contents<2>. (line  207)
* excel_tab (class in csv):              Module Contents<2>. (line  213)
* ExceptHandler (class in ast):          Control flow.       (line  201)
* excepthook() (in module sys):          sys — System-specific parameters and functions.
                                                             (line  392)
* excepthook() (in module threading):    Reference<2>.       (line   26)
* exception:                             Exceptions<2>.      (line    6)
* exception <1>:                         The raise statement.
                                                             (line    6)
* Exception:                             Base classes.       (line   66)
* EXCEPTION (in module _tkinter):        File Handlers.      (line   41)
* exception handler:                     Exceptions<2>.      (line    6)
* EXCEPTION_HANDLED (monitoring event):  Events.             (line   26)
* exception; AssertionError:             The assert statement.
                                                             (line   21)
* exception; AttributeError:             Attribute references.
                                                             (line   10)
* exception; chaining:                   The raise statement.
                                                             (line   30)
* exception; chaining <1>:               Exception context.  (line    6)
* exception; GeneratorExit:              Generator-iterator methods.
                                                             (line   64)
* exception; GeneratorExit <1>:          Asynchronous generator-iterator methods.
                                                             (line   61)
* exception; handler:                    Traceback objects.  (line    6)
* exception; ImportError:                The import statement.
                                                             (line    6)
* exception; NameError:                  Identifiers Names.  (line   10)
* exception; StopAsyncIteration:         Asynchronous generator-iterator methods.
                                                             (line   10)
* exception; StopIteration:              Generator-iterator methods.
                                                             (line   12)
* exception; StopIteration <1>:          The yield statement.
                                                             (line    6)
* exception; TypeError:                  Unary arithmetic and bitwise operations.
                                                             (line   23)
* exception; ValueError:                 Shifting operations.
                                                             (line   20)
* exception; ZeroDivisionError:          Binary arithmetic operations.
                                                             (line   34)
* exception() (asyncio.Future method):   Future Object.      (line  123)
* exception() (asyncio.Task method):     Task object.        (line   87)
* exception() (concurrent.futures.Future method): Future Objects.
                                                             (line   52)
* exception() (in module logging):       Module-Level Functions.
                                                             (line   92)
* exception() (in module sys):           sys — System-specific parameters and functions.
                                                             (line  436)
* exception() (logging.Logger method):   Logger Objects.     (line  318)
* ExceptionGroup:                        Exception groups.   (line   12)
* exceptions (BaseExceptionGroup attribute): Exception groups.
                                                             (line   41)
* exceptions (pdb command):              Debugger commands.  (line  438)
* exceptions (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   53)
* EXCLAMATION (in module token):         token — Constants used with Python parse trees.
                                                             (line  317)
* exclusive; or:                         Binary bitwise operations.
                                                             (line   16)
* EXDEV (in module errno):               errno — Standard errno system symbols.
                                                             (line  102)
* exec_module() (importlib.abc.InspectLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  257)
* exec_module() (importlib.abc.Loader method): importlib abc – Abstract base classes related to import.
                                                             (line  113)
* exec_module() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  404)
* exec_module() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  321)
* exec_module() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   31)
* exec_prefix (in module sys):           sys — System-specific parameters and functions.
                                                             (line  467)
* execl() (in module os):                Process Management. (line   53)
* execle() (in module os):               Process Management. (line   53)
* execlp() (in module os):               Process Management. (line   53)
* execlpe() (in module os):              Process Management. (line   53)
* executable (in module sys):            sys — System-specific parameters and functions.
                                                             (line  484)
* executable (in module sys) <1>:        Process-wide parameters.
                                                             (line  117)
* Executable Zip Files:                  zipapp — Manage executable Python zip archives.
                                                             (line   10)
* execute() (sqlite3.Connection method): Connection objects. (line   97)
* execute() (sqlite3.Cursor method):     Cursor objects.     (line   23)
* executemany() (sqlite3.Connection method): Connection objects.
                                                             (line  103)
* executemany() (sqlite3.Cursor method): Cursor objects.     (line   58)
* executescript() (sqlite3.Connection method): Connection objects.
                                                             (line  109)
* executescript() (sqlite3.Cursor method): Cursor objects.   (line   99)
* execution model:                       Execution model.    (line    6)
* execution; frame:                      Structure of a program.
                                                             (line   18)
* execution; frame <1>:                  Class definitions.  (line    6)
* execution; stack:                      Traceback objects.  (line    6)
* ExecutionLoader (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  270)
* Executor (class in concurrent.futures): Executor Objects.  (line    6)
* execv() (in module os):                Process Management. (line   53)
* execve() (in module os):               Process Management. (line   53)
* execvp() (in module os):               Process Management. (line   53)
* execvpe() (in module os):              Process Management. (line   53)
* EXFULL (in module errno):              errno — Standard errno system symbols.
                                                             (line  250)
* exists() (in module os.path):          os path — Common pathname manipulations.
                                                             (line  117)
* exists() (pathlib.Path method):        Querying file type and status.
                                                             (line   36)
* exists() (tkinter.ttk.Treeview method): ttk Treeview.      (line   89)
* exists() (zipfile.Path method):        Path objects.       (line   74)
* exit (built-in variable):              Constants added by the site module.
                                                             (line   11)
* exit (C function):                     Process Control.    (line   23)
* exit() (argparse.ArgumentParser method): Exiting methods.  (line    6)
* exit() (in module _thread):            _thread — Low-level threading API.
                                                             (line   78)
* exit() (in module sys):                sys — System-specific parameters and functions.
                                                             (line  491)
* exitcode (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  159)
* exitonclick() (in module turtle):      Methods specific to Screen not inherited from TurtleScreen.
                                                             (line   10)
* ExitStack (class in contextlib):       Utilities.          (line  502)
* exp() (decimal.Context method):        Context objects.    (line  315)
* exp() (decimal.Decimal method):        Decimal objects.    (line  231)
* exp() (in module cmath):               Power and logarithmic functions.
                                                             (line    6)
* exp() (in module math):                Power exponential and logarithmic functions.
                                                             (line   12)
* exp2() (in module math):               Power exponential and logarithmic functions.
                                                             (line   18)
* expand_tabs (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  166)
* expand() (re.Match method):            Match Objects.      (line   23)
* ExpandEnvironmentStrings() (in module winreg): Functions<13>.
                                                             (line  228)
* expandNode() (xml.dom.pulldom.DOMEventStream method): DOMEventStream Objects.
                                                             (line   21)
* expandtabs() (bytearray method):       Bytes and Bytearray Operations.
                                                             (line  480)
* expandtabs() (bytes method):           Bytes and Bytearray Operations.
                                                             (line  480)
* expandtabs() (str method):             String Methods<2>.  (line  139)
* expanduser() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  138)
* expanduser() (pathlib.Path method):    Expanding and resolving paths.
                                                             (line   18)
* expandvars() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  162)
* Expat:                                 xml parsers expat — Fast XML parsing using Expat.
                                                             (line   11)
* ExpatError:                            xml parsers expat — Fast XML parsing using Expat.
                                                             (line   24)
* expected (asyncio.IncompleteReadError attribute): Exceptions<13>.
                                                             (line   51)
* expectedFailure() (in module unittest): Skipping tests and expected failures.
                                                             (line   98)
* expectedFailures (unittest.TestResult attribute): Loading and running tests.
                                                             (line  263)
* expired() (asyncio.Timeout method):    Timeouts.           (line   76)
* expires (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   52)
* expires (http.cookies.Morsel attribute): Morsel Objects.   (line   13)
* exploded (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   60)
* exploded (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  109)
* exploded (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  259)
* exploded (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  321)
* expm1() (in module math):              Power exponential and logarithmic functions.
                                                             (line   24)
* expovariate() (in module random):      Real-valued distributions.
                                                             (line   38)
* Expr (class in ast):                   Expressions<2>.     (line    6)
* expression:                            Expressions.        (line    6)
* expression <1>:                        Glossary.           (line  524)
* Expression (class in ast):             Root nodes.         (line   26)
* expression; list:                      Expression lists.   (line    6)
* expression; list <1>:                  Expression statements.
                                                             (line    6)
* expression; list <2>:                  Expression statements.
                                                             (line    6)
* expression; statement:                 Expression statements.
                                                             (line    6)
* expunge() (imaplib.IMAP4 method):      IMAP4 Objects.      (line   93)
* extend_path() (in module pkgutil):     pkgutil — Package extension utility.
                                                             (line   19)
* extend() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  159)
* extend() (collections.deque method):   deque objects.      (line   59)
* extend() (sequence method):            Mutable Sequence Types.
                                                             (line   92)
* extend() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   93)
* EXTENDED_ARG (opcode):                 Python Bytecode Instructions.
                                                             (line 1160)
* ExtendedContext (in module decimal):   Context objects.    (line   76)
* ExtendedInterpolation (class in configparser): Interpolation of values.
                                                             (line   41)
* extendleft() (collections.deque method): deque objects.    (line   64)
* extension module:                      Glossary.           (line  535)
* EXTENSION_SUFFIXES (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   50)
* extension; module:                     The standard type hierarchy.
                                                             (line    6)
* ExtensionFileLoader (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  288)
* extensions_map (http.server.SimpleHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  367)
* External Data Representation:          Data stream format. (line    6)
* external_attr (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  142)
* ExternalClashError:                    Exceptions<18>.     (line   24)
* ExternalEntityParserCreate() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   43)
* ExternalEntityRefHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  423)
* extra (zipfile.ZipInfo attribute):     ZipInfo objects.    (line  108)
* extract_cookies() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   31)
* extract_stack() (in module traceback): Module-Level Functions<2>.
                                                             (line   94)
* extract_tb() (in module traceback):    Module-Level Functions<2>.
                                                             (line   82)
* extract_version (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  122)
* extract() (tarfile.TarFile method):    TarFile Objects.    (line  174)
* extract() (traceback.StackSummary class method): StackSummary Objects.
                                                             (line   12)
* extract() (zipfile.ZipFile method):    ZipFile objects.    (line  186)
* extractall() (tarfile.TarFile method): TarFile Objects.    (line  137)
* extractall() (zipfile.ZipFile method): ZipFile objects.    (line  213)
* ExtractError:                          tarfile — Read and write tar archive files.
                                                             (line  218)
* extractfile() (tarfile.TarFile method): TarFile Objects.   (line  207)
* extraction_filter (tarfile.TarFile attribute): TarFile Objects.
                                                             (line  243)
* extsep (in module os):                 Miscellaneous System Information.
                                                             (line  131)
* f_back (frame attribute):              Frame objects.      (line   10)
* f_back (frame attribute) <1>:          Special read-only attributes<3>.
                                                             (line    6)
* f_builtins (frame attribute):          Frame objects.      (line   10)
* f_builtins (frame attribute) <1>:      Special read-only attributes<3>.
                                                             (line   29)
* f_code (frame attribute):              Frame objects.      (line   10)
* f_code (frame attribute) <1>:          Special read-only attributes<3>.
                                                             (line   10)
* F_CONTIGUOUS (inspect.BufferFlags attribute): Buffer flags.
                                                             (line   27)
* f_contiguous (memoryview attribute):   Memory Views.       (line  483)
* f_globals (frame attribute):           Frame objects.      (line   10)
* f_globals (frame attribute) <1>:       Special read-only attributes<3>.
                                                             (line   25)
* f_lasti (frame attribute):             Frame objects.      (line   10)
* f_lasti (frame attribute) <1>:         Special read-only attributes<3>.
                                                             (line   33)
* f_lineno (frame attribute):            Special read-only attributes<3>.
                                                             (line   37)
* f_lineno (frame attribute) <1>:        Special writable attributes<2>.
                                                             (line   23)
* f_locals (frame attribute):            Frame objects.      (line   10)
* f_locals (frame attribute) <1>:        Special read-only attributes<3>.
                                                             (line   16)
* F_LOCK (in module os):                 File Descriptor Operations.
                                                             (line  280)
* F_OK (in module os):                   Files and Directories.
                                                             (line  107)
* F_TEST (in module os):                 File Descriptor Operations.
                                                             (line  280)
* F_TLOCK (in module os):                File Descriptor Operations.
                                                             (line  280)
* f_trace (frame attribute):             Special read-only attributes<3>.
                                                             (line   38)
* f_trace (frame attribute) <1>:         Special writable attributes<2>.
                                                             (line    6)
* f_trace_lines (frame attribute):       Special read-only attributes<3>.
                                                             (line   38)
* f_trace_lines (frame attribute) <1>:   Special writable attributes<2>.
                                                             (line   12)
* f_trace_opcodes (frame attribute):     Special read-only attributes<3>.
                                                             (line   38)
* f_trace_opcodes (frame attribute) <1>: Special writable attributes<2>.
                                                             (line   16)
* F_ULOCK (in module os):                File Descriptor Operations.
                                                             (line  280)
* f-string:                              Fancier Output Formatting.
                                                             (line   93)
* f-string <1>:                          String literal concatenation.
                                                             (line   24)
* f-string <2>:                          Glossary.           (line  540)
* f-strings:                             String Methods<2>.  (line  966)
* f'; formatted string literal:          String and Bytes literals.
                                                             (line   64)
* f"; formatted string literal:          String and Bytes literals.
                                                             (line   64)
* fabs() (in module math):               Floating point arithmetic.
                                                             (line   13)
* factorial() (in module math):          Number-theoretic functions.
                                                             (line   23)
* factory() (importlib.util.LazyLoader class method): importlib util – Utility code for importers.
                                                             (line  222)
* FAIL_FAST (in module doctest):         Option Flags.       (line  138)
* fail() (unittest.TestCase method):     Test cases.         (line  683)
* failed (doctest.TestResults attribute): TestResults objects.
                                                             (line    8)
* failfast (unittest.TestResult attribute): Loading and running tests.
                                                             (line  301)
* failureException (unittest.TestCase attribute): Test cases.
                                                             (line  688)
* failures (doctest.DocTestRunner attribute): DocTestRunner objects.
                                                             (line  138)
* failures (unittest.TestResult attribute): Loading and running tests.
                                                             (line  249)
* FakePath (class in test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   59)
* False:                                 numbers Integral.   (line   27)
* false:                                 Truth Value Testing.
                                                             (line    6)
* False <1>:                             Truth Value Testing.
                                                             (line   23)
* False <2>:                             Boolean Type - bool.
                                                             (line    9)
* False (Built-in object):               Truth Value Testing.
                                                             (line   15)
* False (built-in variable):             Built-in Constants. (line    8)
* families() (in module tkinter.font):   tkinter font — Tkinter font wrapper.
                                                             (line   88)
* family (socket.socket attribute):      Socket Objects.     (line  611)
* FancyURLopener (class in urllib.request): Legacy interface.
                                                             (line  146)
* fast (pickle.Pickler attribute):       Module Interface.   (line  216)
* FastChildWatcher (class in asyncio):   Process Watchers.   (line  142)
* fatalError() (xml.sax.handler.ErrorHandler method): ErrorHandler Objects.
                                                             (line   24)
* Fault (class in xmlrpc.client):        Fault Objects.      (line    6)
* faultCode (xmlrpc.client.Fault attribute): Fault Objects.  (line   11)
* faultString (xmlrpc.client.Fault attribute): Fault Objects.
                                                             (line   15)
* fchdir() (in module os):               Files and Directories.
                                                             (line  281)
* fchmod() (in module os):               File Descriptor Operations.
                                                             (line  121)
* fchown() (in module os):               File Descriptor Operations.
                                                             (line  137)
* fcntl() (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line   67)
* fd (selectors.SelectorKey attribute):  Classes<4>.         (line   40)
* fd_count() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   96)
* fd() (in module turtle):               Turtle motion.      (line    6)
* fdatasync() (in module os):            File Descriptor Operations.
                                                             (line  152)
* fdopen() (in module os):               File Object Creation.
                                                             (line    9)
* feature_external_ges (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   81)
* feature_external_pes (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   93)
* feature_namespace_prefixes (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   60)
* feature_namespaces (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   53)
* feature_string_interning (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   67)
* feature_validation (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   74)
* FEBRUARY (in module calendar):         calendar — General calendar-related functions.
                                                             (line  488)
* feed_eof() (asyncio.StreamReader method): StreamReader.    (line   16)
* feed() (email.parser.BytesFeedParser method): FeedParser API.
                                                             (line   55)
* feed() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line    8)
* feed() (xml.etree.ElementTree.XMLParser method): XMLParser Objects.
                                                             (line   27)
* feed() (xml.etree.ElementTree.XMLPullParser method): XMLPullParser Objects.
                                                             (line   18)
* feed() (xml.sax.xmlreader.IncrementalParser method): IncrementalParser Objects.
                                                             (line    9)
* FeedParser (class in email.parser):    FeedParser API.     (line   70)
* fetch() (imaplib.IMAP4 method):        IMAP4 Objects.      (line   99)
* fetchall() (sqlite3.Cursor method):    Cursor objects.     (line  148)
* fetchmany() (sqlite3.Cursor method):   Cursor objects.     (line  128)
* fetchone() (sqlite3.Cursor method):    Cursor objects.     (line  121)
* FF (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   60)
* fflags (select.kevent attribute):      Kevent Objects.     (line   90)
* Field (class in dataclasses):          Module contents<5>. (line  309)
* field_size_limit() (in module csv):    Module Contents<2>. (line   96)
* field() (in module dataclasses):       Module contents<5>. (line  212)
* fieldnames (csv.DictReader attribute): Reader Objects.     (line   31)
* fields (uuid.UUID attribute):          uuid — UUID objects according to RFC 4122.
                                                             (line   96)
* fields() (in module dataclasses):      Module contents<5>. (line  337)
* FIFOTYPE (in module tarfile):          tarfile — Read and write tar archive files.
                                                             (line  302)
* file (bdb.Breakpoint attribute):       bdb — Debugger framework.
                                                             (line   82)
* file (pyclbr.Class attribute):         Class Objects<2>.   (line   12)
* file (pyclbr.Function attribute):      Function Objects.   (line   11)
* file object:                           Glossary.           (line  546)
* file object; io module:                Overview<2>.        (line    6)
* file object; open() built-in function: Built-in Functions. (line 1271)
* FILE_ATTRIBUTE_ARCHIVE (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_COMPRESSED (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_DEVICE (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_DIRECTORY (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_ENCRYPTED (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_HIDDEN (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_INTEGRITY_STREAM (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_NO_SCRUB_DATA (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_NORMAL (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_NOT_CONTENT_INDEXED (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_OFFLINE (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_READONLY (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_REPARSE_POINT (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_SPARSE_FILE (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_SYSTEM (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_TEMPORARY (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* FILE_ATTRIBUTE_VIRTUAL (in module stat): stat — Interpreting stat results.
                                                             (line  452)
* file_digest() (in module hashlib):     File hashing.       (line    9)
* file_open() (urllib.request.FileHandler method): FileHandler Objects.
                                                             (line    6)
* file_size (zipfile.ZipInfo attribute): ZipInfo objects.    (line  158)
* file-like object:                      Glossary.           (line  562)
* file; byte-code:                       py_compile — Compile Python source files.
                                                             (line    8)
* file; copying:                         shutil — High-level file operations.
                                                             (line    8)
* file; large files:                     Large File Support. (line    6)
* file; mime.types:                      mimetypes — Map filenames to MIME types.
                                                             (line  137)
* file; modes:                           Built-in Functions. (line 1297)
* fileConfig() (in module logging.config): Configuration functions.
                                                             (line   61)
* FileCookieJar (class in http.cookiejar): http cookiejar — Cookie handling for HTTP clients.
                                                             (line   56)
* FileDialog (class in tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line   78)
* FileExistsError:                       OS exceptions.      (line   63)
* FileFinder (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  153)
* FileHandler (class in logging):        FileHandler.        (line   10)
* FileHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  422)
* FileInput (class in fileinput):        fileinput — Iterate over lines from multiple input streams.
                                                             (line  139)
* FileIO (class in io):                  Raw File I/O.       (line    6)
* filelineno() (in module fileinput):    fileinput — Iterate over lines from multiple input streams.
                                                             (line  104)
* FileLoader (class in importlib.abc):   importlib abc – Abstract base classes related to import.
                                                             (line  289)
* filemode() (in module stat):           stat — Interpreting stat results.
                                                             (line  121)
* filename (doctest.DocTest attribute):  DocTest Objects.    (line   35)
* filename (http.cookiejar.FileCookieJar attribute): CookieJar and FileCookieJar Objects.
                                                             (line  153)
* filename (inspect.FrameInfo attribute): The interpreter stack.
                                                             (line   17)
* filename (inspect.Traceback attribute): The interpreter stack.
                                                             (line   57)
* filename (netrc.NetrcParseError attribute): netrc — netrc file processing.
                                                             (line   56)
* filename (OSError attribute):          Concrete exceptions.
                                                             (line  194)
* filename (SyntaxError attribute):      Concrete exceptions.
                                                             (line  316)
* filename (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   28)
* filename (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   91)
* filename (tracemalloc.Frame attribute): Frame.             (line   12)
* filename (zipfile.ZipFile attribute):  ZipFile objects.    (line  349)
* filename (zipfile.ZipInfo attribute):  ZipInfo objects.    (line   51)
* filename_only (in module tabnanny):    tabnanny — Detection of ambiguous indentation.
                                                             (line   31)
* filename_pattern (tracemalloc.Filter attribute): Filter.   (line   54)
* filename() (in module fileinput):      fileinput — Iterate over lines from multiple input streams.
                                                             (line   86)
* filename2 (OSError attribute):         Concrete exceptions.
                                                             (line  194)
* filenames; pathname expansion:         glob — Unix style pathname pattern expansion.
                                                             (line    8)
* filenames; wildcard expansion:         fnmatch — Unix filename pattern matching.
                                                             (line    8)
* fileno() (bz2.BZ2File method):         De compression of files.
                                                             (line   86)
* fileno() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   36)
* fileno() (in module fileinput):        fileinput — Iterate over lines from multiple input streams.
                                                             (line   91)
* fileno() (io.IOBase method):           I/O Base Classes.   (line   61)
* fileno() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   31)
* fileno() (select.devpoll method):      /dev/poll Polling Objects.
                                                             (line   24)
* fileno() (select.epoll method):        Edge and Level Trigger Polling epoll Objects.
                                                             (line   73)
* fileno() (select.kqueue method):       Kqueue Objects.     (line   14)
* fileno() (selectors.DevpollSelector method): Classes<4>.   (line  188)
* fileno() (selectors.EpollSelector method): Classes<4>.     (line  179)
* fileno() (selectors.KqueueSelector method): Classes<4>.    (line  199)
* fileno() (socket.socket method):       Socket Objects.     (line  117)
* fileno() (socketserver.BaseServer method): Server Objects. (line   14)
* FileNotFoundError:                     OS exceptions.      (line   68)
* fileobj (selectors.SelectorKey attribute): Classes<4>.     (line   36)
* files_double_event() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line   94)
* files_select_event() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line   98)
* files() (importlib.abc.TraversableResources method): importlib abc – Abstract base classes related to import.
                                                             (line  580)
* files() (importlib.resources.abc.TraversableResources method): importlib resources abc – Abstract base classes for resources.
                                                             (line  172)
* files() (in module importlib.metadata): Distribution files.
                                                             (line    6)
* files() (in module importlib.resources): importlib resources – Package resource reading opening and access.
                                                             (line   52)
* filesystem encoding and error handler: Glossary.           (line  566)
* FileType (class in argparse):          FileType objects.   (line    6)
* FileWrapper (class in wsgiref.types):  wsgiref types – WSGI types for static type checking.
                                                             (line   32)
* FileWrapper (class in wsgiref.util):   wsgiref util – WSGI environment utilities.
                                                             (line  117)
* fill() (in module textwrap):           textwrap — Text wrapping and filling.
                                                             (line   33)
* fill() (textwrap.TextWrapper method):  textwrap — Text wrapping and filling.
                                                             (line  293)
* fillcolor() (in module turtle):        Color control.      (line   62)
* filling() (in module turtle):          Filling.            (line    6)
* fillvalue (reprlib.Repr attribute):    Repr Objects.       (line   10)
* Filter (class in logging):             Filter Objects.     (line   13)
* Filter (class in tracemalloc):         Filter.             (line    6)
* filter (select.kevent attribute):      Kevent Objects.     (line   15)
* filter_command() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  102)
* FILTER_DIR (in module unittest.mock):  FILTER_DIR.         (line    6)
* filter_traces() (tracemalloc.Snapshot method): Snapshot.   (line   35)
* filter() (in module curses):           Functions<6>.       (line  121)
* filter() (in module fnmatch):          fnmatch — Unix filename pattern matching.
                                                             (line   75)
* filter() (logging.Filter method):      Filter Objects.     (line   20)
* filter() (logging.Handler method):     Handler Objects.    (line   61)
* filter() (logging.Logger method):      Logger Objects.     (line  333)
* FilterError:                           tarfile — Read and write tar archive files.
                                                             (line  229)
* filterfalse() (in module itertools):   Itertool Functions. (line  289)
* filterwarnings() (in module warnings): Available Functions.
                                                             (line  112)
* Final (in module typing):              Special forms.      (line  223)
* final() (in module typing):            Functions and decorators.
                                                             (line  311)
* finalization, of objects:              Finalization and De-allocation.
                                                             (line    6)
* finalize (class in weakref):           weakref — Weak references.
                                                             (line  266)
* finalizer:                             Basic customization.
                                                             (line   54)
* find_class() (pickle protocol):        Restricting Globals.
                                                             (line    6)
* find_class() (pickle.Unpickler method): Module Interface.  (line  290)
* find_library() (in module ctypes.util): Utility functions. (line  111)
* find_loader() (in module pkgutil):     pkgutil — Package extension utility.
                                                             (line   54)
* find_longest_match() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line   64)
* find_msvcrt() (in module ctypes.util): Utility functions.  (line  123)
* find_spec() (importlib.abc.MetaPathFinder method): importlib abc – Abstract base classes related to import.
                                                             (line   34)
* find_spec() (importlib.abc.PathEntryFinder method): importlib abc – Abstract base classes related to import.
                                                             (line   70)
* find_spec() (importlib.machinery.FileFinder method): importlib machinery – Importers and path hooks.
                                                             (line  183)
* find_spec() (importlib.machinery.PathFinder class method): importlib machinery – Importers and path hooks.
                                                             (line  116)
* find_spec() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  101)
* find_spec() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   38)
* find_unused_port() (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   15)
* find_user_password() (urllib.request.HTTPPasswordMgr method): HTTPPasswordMgr Objects.
                                                             (line   16)
* find_user_password() (urllib.request.HTTPPasswordMgrWithPriorAuth method): HTTPPasswordMgrWithPriorAuth Objects.
                                                             (line   19)
* find() (bytearray method):             Bytes and Bytearray Operations.
                                                             (line  133)
* find() (bytes method):                 Bytes and Bytearray Operations.
                                                             (line  133)
* find() (doctest.DocTestFinder method): DocTestFinder objects.
                                                             (line   32)
* find() (in module gettext):            Class-based API.    (line   14)
* find() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  194)
* find() (str method):                   String Methods<2>.  (line  163)
* find() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  100)
* find() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   21)
* findall() (in module re):              Functions<2>.       (line  131)
* findall() (re.Pattern method):         Regular Expression Objects.
                                                             (line   85)
* findall() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  109)
* findall() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   26)
* findCaller() (logging.Logger method):  Logger Objects.     (line  350)
* finder:                                Finders and loaders.
                                                             (line    6)
* finder <1>:                            Glossary.           (line  586)
* finder; find_spec:                     The meta path.      (line    6)
* findfile() (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line  275)
* finditer() (in module re):             Functions<2>.       (line  157)
* finditer() (re.Pattern method):        Regular Expression Objects.
                                                             (line   91)
* findlabels() (in module dis):          Analysis functions. (line  180)
* findlinestarts() (in module dis):      Analysis functions. (line  163)
* findtext() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  118)
* findtext() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   31)
* finish_request() (socketserver.BaseServer method): Server Objects.
                                                             (line  128)
* finish() (socketserver.BaseRequestHandler method): Request Handler Objects.
                                                             (line   35)
* finish() (tkinter.dnd.DndHandler method): tkinter dnd — Drag and drop support.
                                                             (line   52)
* FIRST_COMPLETED (in module asyncio):   Waiting primitives. (line   35)
* FIRST_COMPLETED (in module concurrent.futures): Module Functions.
                                                             (line   30)
* FIRST_EXCEPTION (in module asyncio):   Waiting primitives. (line   39)
* FIRST_EXCEPTION (in module concurrent.futures): Module Functions.
                                                             (line   34)
* firstChild (xml.dom.Node attribute):   Node Objects.       (line   54)
* FirstHeaderLineIsContinuationDefect:   email errors Exception and Defect classes.
                                                             (line   92)
* firstkey() (dbm.gnu.gdbm method):      dbm gnu — GNU database manager.
                                                             (line  100)
* firstweekday (calendar.Calendar attribute): calendar — General calendar-related functions.
                                                             (line   39)
* firstweekday() (in module calendar):   calendar — General calendar-related functions.
                                                             (line  359)
* fix_missing_locations() (in module ast): ast Helpers.      (line  145)
* fix_sentence_endings (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  221)
* Flag (class in enum):                  Data types.         (line  474)
* flag_bits (zipfile.ZipInfo attribute): ZipInfo objects.    (line  130)
* FlagBoundary (class in enum):          Data types.         (line  710)
* flags (decimal.Context attribute):     Context objects.    (line  133)
* flags (in module sys):                 sys — System-specific parameters and functions.
                                                             (line  522)
* flags (re.Pattern attribute):          Regular Expression Objects.
                                                             (line  107)
* flags (select.kevent attribute):       Kevent Objects.     (line   52)
* flash() (in module curses):            Functions<6>.       (line  132)
* flatten() (email.generator.BytesGenerator method): email generator Generating MIME documents.
                                                             (line   79)
* flatten() (email.generator.Generator method): email generator Generating MIME documents.
                                                             (line  172)
* flattening; objects:                   pickle — Python object serialization.
                                                             (line    8)
* float (built-in class):                Built-in Functions. (line  720)
* float_info (in module sys):            sys — System-specific parameters and functions.
                                                             (line  606)
* float_repr_style (in module sys):      sys — System-specific parameters and functions.
                                                             (line  714)
* floating-point literal:                Numeric literals.   (line    6)
* floating-point; literals:              Numeric Types — int float complex.
                                                             (line   19)
* floating-point; number:                numbers Real float. (line    6)
* FloatingPointError:                    Concrete exceptions.
                                                             (line   40)
* FloatOperation (class in decimal):     Signals.            (line  102)
* flock() (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  160)
* floor division:                        Glossary.           (line  598)
* floor() (in module math):              Numeric Types — int float complex.
                                                             (line  106)
* floor() (in module math) <1>:          Floating point arithmetic.
                                                             (line   17)
* FloorDiv (class in ast):               Expressions<2>.     (line   53)
* floordiv() (in module operator):       operator — Standard operators as functions.
                                                             (line   88)
* flush_headers() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  287)
* flush_std_streams() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  407)
* flush() (bz2.BZ2Compressor method):    Incremental de compression.
                                                             (line   25)
* flush() (io.BufferedWriter method):    Buffered Streams.   (line  118)
* flush() (io.IOBase method):            I/O Base Classes.   (line   67)
* flush() (logging.Handler method):      Handler Objects.    (line   69)
* flush() (logging.handlers.BufferingHandler method): MemoryHandler.
                                                             (line   30)
* flush() (logging.handlers.MemoryHandler method): MemoryHandler.
                                                             (line   61)
* flush() (logging.StreamHandler method): StreamHandler.     (line   25)
* flush() (lzma.LZMACompressor method):  Compressing and decompressing data in memory.
                                                             (line   89)
* flush() (mailbox.Mailbox method):      Mailbox objects.    (line  248)
* flush() (mailbox.Maildir method):      Maildir objects.    (line  204)
* flush() (mailbox.MH method):           MH objects.         (line  102)
* flush() (mmap.mmap method):            mmap — Memory-mapped file support.
                                                             (line  204)
* flush() (xml.etree.ElementTree.XMLParser method): XMLParser Objects.
                                                             (line   31)
* flush() (xml.etree.ElementTree.XMLPullParser method): XMLPullParser Objects.
                                                             (line   22)
* flush() (zlib.Compress method):        zlib — Compression compatible with gzip.
                                                             (line  210)
* flush() (zlib.Decompress method):      zlib — Compression compatible with gzip.
                                                             (line  282)
* flushinp() (in module curses):         Functions<6>.       (line  139)
* FlushKey() (in module winreg):         Functions<13>.      (line  239)
* fma() (decimal.Context method):        Context objects.    (line  319)
* fma() (decimal.Decimal method):        Decimal objects.    (line  268)
* fma() (in module math):                Floating point arithmetic.
                                                             (line   23)
* fmean() (in module statistics):        Function details.   (line   49)
* fmod() (in module math):               Floating point arithmetic.
                                                             (line   38)
* FMT_BINARY (in module plistlib):       plistlib — Generate and parse Apple plist files.
                                                             (line  162)
* FMT_XML (in module plistlib):          plistlib — Generate and parse Apple plist files.
                                                             (line  156)
* fnmatch() (in module fnmatch):         fnmatch — Unix filename pattern matching.
                                                             (line   50)
* fnmatchcase() (in module fnmatch):     fnmatch — Unix filename pattern matching.
                                                             (line   69)
* focus() (tkinter.ttk.Treeview method): ttk Treeview.       (line   93)
* fold (datetime.datetime attribute):    datetime Objects.   (line  338)
* fold (datetime.time attribute):        time Objects.       (line   71)
* fold_binary() (email.policy.Compat32 method): email policy Policy Objects.
                                                             (line  607)
* fold_binary() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  486)
* fold_binary() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  350)
* fold() (email.headerregistry.BaseHeader method): email headerregistry Custom Header Objects.
                                                             (line   72)
* fold() (email.policy.Compat32 method): email policy Policy Objects.
                                                             (line  599)
* fold() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  466)
* fold() (email.policy.Policy method):   email policy Policy Objects.
                                                             (line  335)
* Font (class in tkinter.font):          tkinter font — Tkinter font wrapper.
                                                             (line   20)
* For (class in ast):                    Control flow.       (line   44)
* FOR_ITER (opcode):                     Python Bytecode Instructions.
                                                             (line  898)
* for; in comprehensions:                Displays for lists sets and dictionaries.
                                                             (line   14)
* forget() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   11)
* forget() (tkinter.ttk.Notebook method): ttk Notebook.      (line   18)
* fork() (in module os):                 Process Management. (line  253)
* fork() (in module pty):                pty — Pseudo-terminal utilities.
                                                             (line   22)
* ForkingMixIn (class in socketserver):  Server Creation Notes.
                                                             (line   27)
* ForkingTCPServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ForkingUDPServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ForkingUnixDatagramServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ForkingUnixStreamServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* forkpty() (in module os):              Process Management. (line  297)
* FORMAT (inspect.BufferFlags attribute): Buffer flags.      (line   19)
* format (memoryview attribute):         Memory Views.       (line  424)
* format (multiprocessing.shared_memory.ShareableList attribute): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  341)
* format (struct.Struct attribute):      Classes<3>.         (line   54)
* format_datetime() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  172)
* format_exc() (in module traceback):    Module-Level Functions<2>.
                                                             (line  164)
* format_exception_only() (in module traceback): Module-Level Functions<2>.
                                                             (line  118)
* format_exception_only() (traceback.TracebackException method): TracebackException Objects.
                                                             (line  155)
* format_exception() (in module traceback): Module-Level Functions<2>.
                                                             (line  148)
* format_field() (string.Formatter method): Custom string formatting.
                                                             (line  101)
* format_frame_summary() (traceback.StackSummary method): StackSummary Objects.
                                                             (line   53)
* format_help() (argparse.ArgumentParser method): Printing help.
                                                             (line   30)
* format_list() (in module traceback):   Module-Level Functions<2>.
                                                             (line  108)
* format_map() (str method):             String Methods<2>.  (line  218)
* FORMAT_SIMPLE (opcode):                Python Bytecode Instructions.
                                                             (line 1186)
* format_stack_entry() (bdb.Bdb method): bdb — Debugger framework.
                                                             (line  408)
* format_stack() (in module traceback):  Module-Level Functions<2>.
                                                             (line  173)
* format_string() (in module locale):    locale — Internationalization services.
                                                             (line  461)
* format_tb() (in module traceback):     Module-Level Functions<2>.
                                                             (line  169)
* format_usage() (argparse.Action method): Action classes.   (line   57)
* format_usage() (argparse.ArgumentParser method): Printing help.
                                                             (line   25)
* FORMAT_WITH_SPEC (opcode):             Python Bytecode Instructions.
                                                             (line 1198)
* format() (built-in function); __str__() (object method): Basic customization.
                                                             (line  129)
* format() (inspect.Signature method):   Introspecting callables with the Signature object.
                                                             (line  156)
* format() (logging.BufferingFormatter method): Formatter Objects.
                                                             (line  154)
* format() (logging.Formatter method):   Formatter Objects.  (line   51)
* format() (logging.Handler method):     Handler Objects.    (line  104)
* format() (pprint.PrettyPrinter method): PrettyPrinter Objects.
                                                             (line   82)
* format() (str method):                 String Methods<2>.  (line  184)
* format() (string.Formatter method):    Custom string formatting.
                                                             (line   17)
* format() (traceback.StackSummary method): StackSummary Objects.
                                                             (line   38)
* format() (traceback.TracebackException method): TracebackException Objects.
                                                             (line  143)
* format() (tracemalloc.Traceback method): Traceback.        (line   37)
* formataddr() (in module email.utils):  email utils Miscellaneous utilities.
                                                             (line   71)
* formatargvalues() (in module inspect): Classes and functions<2>.
                                                             (line   73)
* formatdate() (in module email.utils):  email utils Miscellaneous utilities.
                                                             (line  151)
* formatday() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  155)
* FormatError:                           Exceptions<18>.     (line   31)
* FormatError() (in module ctypes):      Utility functions.  (line  135)
* formatException() (logging.Formatter method): Formatter Objects.
                                                             (line  116)
* formatFooter() (logging.BufferingFormatter method): Formatter Objects.
                                                             (line  147)
* formatHeader() (logging.BufferingFormatter method): Formatter Objects.
                                                             (line  140)
* formatmonth() (calendar.HTMLCalendar method): calendar — General calendar-related functions.
                                                             (line  228)
* formatmonth() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  184)
* formatmonthname() (calendar.HTMLCalendar method): calendar — General calendar-related functions.
                                                             (line  249)
* formatmonthname() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  193)
* formatStack() (logging.Formatter method): Formatter Objects.
                                                             (line  124)
* formatted string literal:              Fancier Output Formatting.
                                                             (line   93)
* formatted string literal <1>:          String literal concatenation.
                                                             (line   24)
* formatted string literals:             String Methods<2>.  (line  966)
* FormattedValue (class in ast):         Literals<3>.        (line   18)
* Formatter (class in logging):          Formatter Objects.  (line    6)
* Formatter (class in string):           Custom string formatting.
                                                             (line   13)
* formatTime() (logging.Formatter method): Formatter Objects.
                                                             (line   76)
* formatting, string (%):                printf-style String Formatting.
                                                             (line    6)
* formatting; bytearray (%):             printf-style Bytes Formatting.
                                                             (line    6)
* formatting; bytes (%):                 printf-style Bytes Formatting.
                                                             (line    6)
* formatwarning() (in module warnings):  Available Functions.
                                                             (line  103)
* formatweek() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  162)
* formatweekday() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  170)
* formatweekheader() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  177)
* formatyear() (calendar.HTMLCalendar method): calendar — General calendar-related functions.
                                                             (line  234)
* formatyear() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  207)
* formatyearpage() (calendar.HTMLCalendar method): calendar — General calendar-related functions.
                                                             (line  239)
* Fortran contiguous:                    shape strides suboffsets.
                                                             (line   33)
* Fortran contiguous <1>:                Glossary.           (line  358)
* forward() (in module turtle):          Turtle motion.      (line    6)
* ForwardRef (class in typing):          Introspection helpers.
                                                             (line  149)
* fp (urllib.error.HTTPError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   60)
* fpathconf() (in module os):            File Descriptor Operations.
                                                             (line  161)
* Fraction (class in fractions):         fractions — Rational numbers.
                                                             (line   15)
* Frame (class in tracemalloc):          Frame.              (line    6)
* frame (inspect.FrameInfo attribute):   The interpreter stack.
                                                             (line   13)
* frame (tkinter.scrolledtext.ScrolledText attribute): tkinter scrolledtext — Scrolled Text Widget.
                                                             (line   26)
* FrameInfo (class in inspect):          The interpreter stack.
                                                             (line   11)
* FrameSummary (class in traceback):     FrameSummary Objects.
                                                             (line   11)
* FrameType (in module types):           Standard Interpreter Types.
                                                             (line  195)
* free (C function):                     Overview<4>.        (line   33)
* free threading:                        Glossary.           (line  606)
* free variable:                         Glossary.           (line  613)
* free_tool_id() (in module sys.monitoring): Registering and using tools.
                                                             (line   13)
* free; variable:                        Binding of names.   (line   48)
* freedesktop_os_release() (in module platform): Linux platforms.
                                                             (line    6)
* freefunc (C type):                     Slot Type typedefs. (line   27)
* freeze utility:                        Importing Modules<2>.
                                                             (line  273)
* freeze_support() (in module multiprocessing): Miscellaneous<3>.
                                                             (line   50)
* freeze() (in module gc):               gc — Garbage Collector interface.
                                                             (line  204)
* frexp() (in module math):              Floating point manipulation functions.
                                                             (line   12)
* FRIDAY (in module calendar):           calendar — General calendar-related functions.
                                                             (line  445)
* from_address() (ctypes._CData method): Data types<2>.      (line   42)
* from_buffer_copy() (ctypes._CData method): Data types<2>.  (line   31)
* from_buffer() (ctypes._CData method):  Data types<2>.      (line   19)
* from_bytes() (int class method):       Additional Methods on Integer Types.
                                                             (line  111)
* from_callable() (inspect.Signature class method): Introspecting callables with the Signature object.
                                                             (line  167)
* from_decimal() (fractions.Fraction class method): fractions — Rational numbers.
                                                             (line  144)
* from_exception() (traceback.TracebackException class method): TracebackException Objects.
                                                             (line  126)
* from_file() (zipfile.ZipInfo class method): ZipInfo objects.
                                                             (line   14)
* from_file() (zoneinfo.ZoneInfo class method): The ZoneInfo class.
                                                             (line   28)
* from_float() (decimal.Decimal class method): Decimal objects.
                                                             (line  242)
* from_float() (fractions.Fraction class method): fractions — Rational numbers.
                                                             (line  134)
* from_iterable() (itertools.chain class method): Itertool Functions.
                                                             (line  117)
* from_list() (traceback.StackSummary class method): StackSummary Objects.
                                                             (line   31)
* from_param() (ctypes._CData method):   Data types<2>.      (line   51)
* from_samples() (statistics.NormalDist class method): NormalDist objects.
                                                             (line   45)
* from_traceback() (dis.Bytecode class method): Bytecode analysis.
                                                             (line   43)
* from_uri() (pathlib.Path class method): Parsing and generating URIs.
                                                             (line   12)
* from; import statement:                Binding of names.   (line    9)
* from; import statement <1>:            The import statement.
                                                             (line   52)
* from; yield from expression:           Yield expressions.  (line   66)
* frombuf() (tarfile.TarInfo class method): TarInfo Objects. (line   37)
* frombytes() (array.array method):      array — Efficient arrays of numeric values.
                                                             (line  167)
* fromfd() (in module socket):           Creating sockets.   (line  158)
* fromfd() (select.epoll method):        Edge and Level Trigger Polling epoll Objects.
                                                             (line   77)
* fromfd() (select.kqueue method):       Kqueue Objects.     (line   18)
* fromfile() (array.array method):       array — Efficient arrays of numeric values.
                                                             (line  177)
* fromhex() (bytearray class method):    Bytearray Objects.  (line   38)
* fromhex() (bytes class method):        Bytes Objects.      (line   64)
* fromhex() (float class method):        Additional Methods on Float.
                                                             (line   39)
* fromisocalendar() (datetime.date class method): date Objects.
                                                             (line   91)
* fromisocalendar() (datetime.datetime class method): datetime Objects.
                                                             (line  245)
* fromisoformat() (datetime.date class method): date Objects.
                                                             (line   63)
* fromisoformat() (datetime.datetime class method): datetime Objects.
                                                             (line  196)
* fromisoformat() (datetime.time class method): time Objects.
                                                             (line  107)
* fromkeys() (collections.Counter method): Counter objects.  (line  125)
* fromkeys() (dict class method):        Mapping Types — dict.
                                                             (line  169)
* fromlist() (array.array method):       array — Efficient arrays of numeric values.
                                                             (line  185)
* fromordinal() (datetime.date class method): date Objects.  (line   54)
* fromordinal() (datetime.datetime class method): datetime Objects.
                                                             (line  170)
* fromshare() (in module socket):        Creating sockets.   (line  175)
* fromstring() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line   99)
* fromstringlist() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  107)
* fromtarfile() (tarfile.TarInfo class method): TarInfo Objects.
                                                             (line   44)
* fromtimestamp() (datetime.date class method): date Objects.
                                                             (line   35)
* fromtimestamp() (datetime.datetime class method): datetime Objects.
                                                             (line  100)
* fromunicode() (array.array method):    array — Efficient arrays of numeric values.
                                                             (line  191)
* fromutc() (datetime.timezone method):  timezone Objects.   (line   61)
* fromutc() (datetime.tzinfo method):    tzinfo Objects.     (line  164)
* FrozenImporter (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   80)
* FrozenInstanceError:                   Module contents<5>. (line  513)
* frozenset (built-in class):            Set Types — set frozenset.
                                                             (line   33)
* FrozenSet (class in typing):           Aliases to built-in types.
                                                             (line   42)
* FS (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line  108)
* fs_is_case_insensitive() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  100)
* FS_NONASCII (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   10)
* fsdecode() (in module os):             Process Parameters. (line   94)
* fsencode() (in module os):             Process Parameters. (line   81)
* fspath() (in module os):               Process Parameters. (line  107)
* fstat() (in module os):                File Descriptor Operations.
                                                             (line  183)
* fstatvfs() (in module os):             File Descriptor Operations.
                                                             (line  195)
* fstring:                               Fancier Output Formatting.
                                                             (line   93)
* fstring <1>:                           String literal concatenation.
                                                             (line   24)
* fstring <2>:                           String Methods<2>.  (line  966)
* FSTRING_END (in module token):         token — Constants used with Python parse trees.
                                                             (line  115)
* FSTRING_MIDDLE (in module token):      token — Constants used with Python parse trees.
                                                             (line  105)
* FSTRING_START (in module token):       token — Constants used with Python parse trees.
                                                             (line   96)
* fsum() (in module math):               Summation and product functions.
                                                             (line   18)
* fsync() (in module os):                File Descriptor Operations.
                                                             (line  203)
* FTP:                                   urllib request Restrictions.
                                                             (line   37)
* FTP (class in ftplib):                 FTP objects.        (line    6)
* ftp_open() (urllib.request.FTPHandler method): FTPHandler Objects.
                                                             (line    6)
* FTP_TLS (class in ftplib):             FTP_TLS objects.    (line    6)
* FTP; ftplib (standard module):         ftplib — FTP protocol client.
                                                             (line    8)
* FTP; protocol:                         urllib request Restrictions.
                                                             (line    6)
* FTP; protocol <1>:                     ftplib — FTP protocol client.
                                                             (line    8)
* FTPHandler (class in urllib.request):  urllib request — Extensible library for opening URLs.
                                                             (line  432)
* ftruncate() (in module os):            File Descriptor Operations.
                                                             (line  216)
* Full:                                  queue — A synchronized queue class.
                                                             (line   86)
* FULL (inspect.BufferFlags attribute):  Buffer flags.       (line   45)
* full_match() (pathlib.PurePath method): Methods and properties.
                                                             (line  254)
* FULL_RO (inspect.BufferFlags attribute): Buffer flags.     (line   47)
* full_url (urllib.request.Request attribute): Request Objects.
                                                             (line   11)
* full() (asyncio.Queue method):         Queue.              (line   31)
* full() (multiprocessing.Queue method): Pipes and Queues.   (line  127)
* full() (queue.Queue method):           Queue Objects.      (line   22)
* fullmatch() (in module re):            Functions<2>.       (line   67)
* fullmatch() (re.Pattern method):       Regular Expression Objects.
                                                             (line   62)
* fully_trusted_filter() (in module tarfile): Default named filters.
                                                             (line    9)
* func (functools.partial attribute):    partial Objects.    (line    9)
* funcname (bdb.Breakpoint attribute):   bdb — Debugger framework.
                                                             (line   98)
* function:                              Glossary.           (line  622)
* Function (class in pyclbr):            Function Objects.   (line    6)
* Function (class in symtable):          Examining Symbol Tables.
                                                             (line  122)
* function (inspect.FrameInfo attribute): The interpreter stack.
                                                             (line   27)
* function (inspect.Traceback attribute): The interpreter stack.
                                                             (line   67)
* FUNCTION (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   15)
* function annotation:                   Glossary.           (line  630)
* function; annotations:                 Function Annotations.
                                                             (line    6)
* function; annotations <1>:             Function definitions.
                                                             (line  109)
* function; argument:                    Callable types.     (line    6)
* function; call:                        Callable types.     (line    6)
* function; call <1>:                    Calls.              (line  132)
* function; call <2>:                    Calls.              (line  142)
* function; definition:                  The return statement.
                                                             (line    6)
* function; definition <1>:              Function definitions.
                                                             (line    6)
* function; generator:                   The yield statement.
                                                             (line    6)
* function; name:                        Function definitions.
                                                             (line    6)
* function; name <1>:                    Function definitions.
                                                             (line    6)
* FunctionDef (class in ast):            Function and class definitions.
                                                             (line    6)
* FunctionTestCase (class in unittest):  Test cases.         (line  948)
* FunctionType (class in ast):           Root nodes.         (line   57)
* FunctionType (in module types):        Standard Interpreter Types.
                                                             (line   25)
* funny_files (filecmp.dircmp attribute): The dircmp class.  (line   99)
* Future (class in asyncio):             Future Object.      (line    6)
* Future (class in concurrent.futures):  Future Objects.     (line   10)
* future; statement:                     Future statements.  (line    6)
* FutureWarning:                         Warnings.           (line   55)
* fwalk() (in module os):                Files and Directories.
                                                             (line 1737)
* gaierror:                              Exceptions<15>.     (line   27)
* gamma() (in module math):              Special functions.  (line   28)
* gammavariate() (in module random):     Real-valued distributions.
                                                             (line   48)
* garbage (in module gc):                gc — Garbage Collector interface.
                                                             (line  238)
* garbage collection:                    Objects values and types.
                                                             (line   36)
* garbage collection <1>:                Glossary.           (line  663)
* gather() (curses.textpad.Textbox method): Textbox objects. (line  109)
* gather() (in module asyncio):          Running tasks concurrently.
                                                             (line    6)
* gauss() (in module random):            Real-valued distributions.
                                                             (line   61)
* gc_collect() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  360)
* gcd() (in module math):                Number-theoretic functions.
                                                             (line   30)
* gcvisitobjects_t (C type):             Querying Garbage Collector State.
                                                             (line   26)
* ge() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* generate_tokens() (in module tokenize): Tokenizing Input.  (line   36)
* generator:                             Glossary.           (line  672)
* generator <1>:                         Glossary.           (line  672)
* Generator (class in collections.abc):  Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   55)
* Generator (class in email.generator):  email generator Generating MIME documents.
                                                             (line  137)
* Generator (class in typing):           Aliases to other ABCs in collections abc.
                                                             (line   37)
* generator expression:                  Glossary.           (line  694)
* generator expression <1>:              Glossary.           (line  694)
* generator iterator:                    Glossary.           (line  682)
* generator_stop (in module __future__): Module Contents<4>. (line   43)
* generator; expression:                 Generator expressions.
                                                             (line    6)
* generator; function:                   Generator functions.
                                                             (line    6)
* generator; function <1>:               Yield expressions.  (line    6)
* generator; function <2>:               The yield statement.
                                                             (line    6)
* generator; iterator:                   Generator functions.
                                                             (line    6)
* generator; iterator <1>:               The yield statement.
                                                             (line    6)
* GeneratorExit:                         Concrete exceptions.
                                                             (line   44)
* GeneratorExp (class in ast):           Comprehensions.     (line    6)
* generators (in module __future__):     Module Contents<4>. (line   18)
* GeneratorType (in module types):       Standard Interpreter Types.
                                                             (line   37)
* Generic (class in typing):             Building generic types and type aliases.
                                                             (line   15)
* generic function:                      Glossary.           (line  703)
* generic type:                          Glossary.           (line  711)
* generic_visit() (ast.NodeVisitor method): ast Helpers.     (line  201)
* Generic; Alias:                        Generic Alias Type. (line    6)
* generic; special; attribute:           The standard type hierarchy.
                                                             (line   13)
* GenericAlias (class in types):         Standard Interpreter Types.
                                                             (line  150)
* genops() (in module pickletools):      Programmatic Interface<2>.
                                                             (line   22)
* geometric_mean() (in module statistics): Function details. (line   77)
* GET_AITER (opcode):                    Python Bytecode Instructions.
                                                             (line  322)
* get_all_breaks() (bdb.Bdb method):     bdb — Debugger framework.
                                                             (line  392)
* get_all_start_methods() (in module multiprocessing): Miscellaneous<3>.
                                                             (line   76)
* get_all() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  254)
* get_all() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  362)
* get_all() (wsgiref.headers.Headers method): wsgiref headers – WSGI response header tools.
                                                             (line   50)
* GET_ANEXT (opcode):                    Python Bytecode Instructions.
                                                             (line  331)
* get_annotations() (in module inspect): Classes and functions<2>.
                                                             (line  156)
* get_app() (wsgiref.simple_server.WSGIServer method): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   68)
* get_archive_formats() (in module shutil): Archiving operations.
                                                             (line   67)
* get_args() (in module typing):         Introspection helpers.
                                                             (line   82)
* get_asyncgen_hooks() (in module sys):  sys — System-specific parameters and functions.
                                                             (line 1003)
* get_attribute() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  595)
* GET_AWAITABLE (opcode):                Python Bytecode Instructions.
                                                             (line  303)
* get_begidx() (in module readline):     Completion.         (line   40)
* get_blocking() (in module os):         File Descriptor Operations.
                                                             (line  229)
* get_body_encoding() (email.charset.Charset method): email charset Representing character sets.
                                                             (line   96)
* get_body() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  518)
* get_boundary() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  403)
* get_boundary() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  580)
* get_bpbynumber() (bdb.Bdb method):     bdb — Debugger framework.
                                                             (line  368)
* get_break() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  377)
* get_breaks() (bdb.Bdb method):         bdb — Debugger framework.
                                                             (line  382)
* get_buffer() (asyncio.BufferedProtocol method): Buffered Streaming Protocols.
                                                             (line   21)
* get_bytes() (mailbox.Mailbox method):  Mailbox objects.    (line  166)
* get_bytes() (mailbox.mbox method):     mbox objects.       (line   32)
* get_bytes() (mailbox.MMDF method):     MMDF objects.       (line   29)
* get_ca_certs() (ssl.SSLContext method): SSL contexts.      (line  178)
* get_cache_token() (in module abc):     abc — Abstract Base Classes.
                                                             (line  326)
* get_channel_binding() (ssl.SSLSocket method): SSL sockets. (line  260)
* get_charset() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  266)
* get_charsets() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  431)
* get_charsets() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  614)
* get_child_watcher() (asyncio.AbstractEventLoopPolicy method): Policy Objects.
                                                             (line   33)
* get_child_watcher() (in module asyncio): Process Watchers. (line   25)
* get_children() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line  118)
* get_children() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line   19)
* get_ciphers() (ssl.SSLContext method): SSL contexts.       (line  192)
* get_clock_info() (in module time):     Functions<5>.       (line  105)
* get_close_matches() (in module difflib): difflib — Helpers for computing deltas.
                                                             (line  204)
* get_code() (importlib.abc.InspectLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  204)
* get_code() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  399)
* get_code() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  333)
* get_code() (importlib.machinery.SourcelessFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  269)
* get_code() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   45)
* get_completer_delims() (in module readline): Completion.   (line   50)
* get_completer() (in module readline):  Completion.         (line   29)
* get_completion_type() (in module readline): Completion.    (line   34)
* get_config_h_filename() (in module sysconfig): Other functions<3>.
                                                             (line   64)
* get_config_var() (in module sysconfig): Configuration variables.
                                                             (line   26)
* get_config_vars() (in module sysconfig): Configuration variables.
                                                             (line   16)
* get_content_charset() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  424)
* get_content_charset() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  603)
* get_content_disposition() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  455)
* get_content_disposition() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  628)
* get_content_maintype() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  324)
* get_content_maintype() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  432)
* get_content_subtype() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  330)
* get_content_subtype() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  438)
* get_content_type() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  308)
* get_content_type() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  416)
* get_content() (email.contentmanager.ContentManager method): email contentmanager Managing MIME Content.
                                                             (line   19)
* get_content() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  582)
* get_content() (in module email.contentmanager): Content Manager Instances.
                                                             (line   24)
* get_context() (asyncio.Handle method): Callback handles.   (line   11)
* get_context() (asyncio.Task method):   Task object.        (line  170)
* get_context() (in module multiprocessing): Miscellaneous<3>.
                                                             (line   85)
* get_coro() (asyncio.Task method):      Task object.        (line  157)
* get_coroutine_origin_tracking_depth() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1017)
* get_count() (in module gc):            gc — Garbage Collector interface.
                                                             (line  113)
* get_current_history_length() (in module readline): History list.
                                                             (line   14)
* get_data() (importlib.abc.FileLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  321)
* get_data() (importlib.abc.ResourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  184)
* get_data() (in module pkgutil):        pkgutil — Package extension utility.
                                                             (line  184)
* get_data() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   50)
* get_date() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   92)
* get_debug() (asyncio.loop method):     Enabling debug mode.
                                                             (line    6)
* get_debug() (in module gc):            gc — Garbage Collector interface.
                                                             (line   58)
* get_default_scheme() (in module sysconfig): Installation path functions.
                                                             (line   14)
* get_default_type() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  335)
* get_default_type() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  443)
* get_default_verify_paths() (in module ssl): Certificate handling.
                                                             (line   62)
* get_default() (argparse.ArgumentParser method): Parser defaults.
                                                             (line   35)
* get_dialect() (in module csv):         Module Contents<2>. (line   86)
* get_disassembly_as_string() (test.support.bytecode_helper.BytecodeTestCase method): test support bytecode_helper — Support tools for testing correct bytecode generation.
                                                             (line   18)
* get_docstring() (in module ast):       ast Helpers.        (line  122)
* get_doctest() (doctest.DocTestParser method): DocTestParser objects.
                                                             (line   13)
* get_endidx() (in module readline):     Completion.         (line   40)
* get_environ() (wsgiref.simple_server.WSGIRequestHandler method): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   90)
* get_errno() (in module ctypes):        Utility functions.  (line  151)
* get_escdelay() (in module curses):     Functions<6>.       (line  447)
* get_event_loop_policy() (in module asyncio): Getting and Setting the Policy.
                                                             (line    9)
* get_event_loop() (asyncio.AbstractEventLoopPolicy method): Policy Objects.
                                                             (line   12)
* get_event_loop() (in module asyncio):  Event loop.         (line   39)
* get_events() (in module sys.monitoring): Setting events globally.
                                                             (line    9)
* get_examples() (doctest.DocTestParser method): DocTestParser objects.
                                                             (line   22)
* get_exception_handler() (asyncio.loop method): Error handling API.
                                                             (line   27)
* get_exec_path() (in module os):        Process Parameters. (line  162)
* get_extra_info() (asyncio.BaseTransport method): Base Transport.
                                                             (line   21)
* get_extra_info() (asyncio.StreamWriter method): StreamWriter.
                                                             (line   64)
* get_field() (string.Formatter method): Custom string formatting.
                                                             (line   55)
* get_file_breaks() (bdb.Bdb method):    bdb — Debugger framework.
                                                             (line  387)
* get_file() (mailbox.Babyl method):     Babyl objects.      (line   49)
* get_file() (mailbox.Mailbox method):   Mailbox objects.    (line  182)
* get_file() (mailbox.Maildir method):   Maildir objects.    (line  221)
* get_file() (mailbox.mbox method):      mbox objects.       (line   39)
* get_file() (mailbox.MH method):        MH objects.         (line   96)
* get_file() (mailbox.MMDF method):      MMDF objects.       (line   36)
* get_filename() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  393)
* get_filename() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  570)
* get_filename() (importlib.abc.ExecutionLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  276)
* get_filename() (importlib.abc.FileLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  317)
* get_filename() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  341)
* get_filename() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   58)
* get_filter() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  106)
* get_flags() (mailbox.Maildir method):  Maildir objects.    (line   92)
* get_flags() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   63)
* get_flags() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   64)
* get_flags() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   63)
* get_folder() (mailbox.Maildir method): Maildir objects.    (line   69)
* get_folder() (mailbox.MH method):      MH objects.         (line   39)
* get_frees() (symtable.Function method): Examining Symbol Tables.
                                                             (line  145)
* get_freeze_count() (in module gc):     gc — Garbage Collector interface.
                                                             (line  229)
* get_from() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   47)
* get_from() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   46)
* get_full_url() (urllib.request.Request method): Request Objects.
                                                             (line  106)
* get_globals() (symtable.Function method): Examining Symbol Tables.
                                                             (line  136)
* get_grouped_opcodes() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  168)
* get_handle_inheritable() (in module os): Inheritance of File Descriptors.
                                                             (line   36)
* get_header() (urllib.request.Request method): Request Objects.
                                                             (line  120)
* get_history_item() (in module readline): History list.     (line   20)
* get_history_length() (in module readline): History file.   (line   30)
* get_id() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   69)
* get_ident() (in module _thread):       _thread — Low-level threading API.
                                                             (line   88)
* get_ident() (in module threading):     Reference<2>.       (line   73)
* get_identifiers() (string.Template method): Template strings.
                                                             (line   75)
* get_identifiers() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line  103)
* get_importer() (in module pkgutil):    pkgutil — Package extension utility.
                                                             (line   72)
* get_info() (mailbox.Maildir method):   Maildir objects.    (line  155)
* get_info() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line  102)
* get_inheritable() (in module os):      Inheritance of File Descriptors.
                                                             (line   27)
* get_inheritable() (socket.socket method): Socket Objects.  (line  126)
* get_instructions() (in module dis):    Analysis functions. (line  136)
* get_int_max_str_digits() (in module sys): sys — System-specific parameters and functions.
                                                             (line  819)
* get_interpreter() (in module zipapp):  Python API.         (line   83)
* GET_ITER (opcode):                     Python Bytecode Instructions.
                                                             (line  214)
* get_key() (selectors.BaseSelector method): Classes<4>.     (line  145)
* get_labels() (mailbox.Babyl method):   Babyl objects.      (line   35)
* get_labels() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   47)
* get_last_error() (in module ctypes):   Utility functions.  (line  159)
* GET_LEN (opcode):                      Python Bytecode Instructions.
                                                             (line  524)
* get_line_buffer() (in module readline): Line buffer.       (line    8)
* get_lineno() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   85)
* get_loader() (in module pkgutil):      pkgutil — Package extension utility.
                                                             (line   86)
* get_local_events() (in module sys.monitoring): Per code object events.
                                                             (line   11)
* get_locals() (symtable.Function method): Examining Symbol Tables.
                                                             (line  132)
* get_logger() (in module multiprocessing): Logging<2>.      (line   11)
* get_loop() (asyncio.Future method):    Future Object.      (line  136)
* get_loop() (asyncio.Runner method):    Runner context manager.
                                                             (line   57)
* get_loop() (asyncio.Server method):    Server objects.     (line   69)
* get_makefile_filename() (in module sysconfig): Other functions<3>.
                                                             (line   68)
* get_map() (selectors.BaseSelector method): Classes<4>.     (line  153)
* get_matching_blocks() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  107)
* get_message() (mailbox.Mailbox method): Mailbox objects.   (line  159)
* get_method() (urllib.request.Request method): Request Objects.
                                                             (line   68)
* get_methods() (symtable.Class method): Examining Symbol Tables.
                                                             (line  155)
* get_mixed_type_key() (in module ipaddress): Other Module Level Functions.
                                                             (line   56)
* get_name() (asyncio.Task method):      Task object.        (line  177)
* get_name() (symtable.Symbol method):   Examining Symbol Tables.
                                                             (line  196)
* get_name() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   73)
* get_namespace() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  267)
* get_namespaces() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  263)
* get_native_id() (in module _thread):   _thread — Low-level threading API.
                                                             (line   96)
* get_native_id() (in module threading): Reference<2>.       (line   83)
* get_nonlocals() (symtable.Function method): Examining Symbol Tables.
                                                             (line  140)
* get_nonstandard_attr() (http.cookiejar.Cookie method): Cookie Objects<2>.
                                                             (line  100)
* get_nowait() (asyncio.Queue method):   Queue.              (line   48)
* get_nowait() (multiprocessing.Queue method): Pipes and Queues.
                                                             (line  168)
* get_nowait() (queue.Queue method):     Queue Objects.      (line   66)
* get_nowait() (queue.SimpleQueue method): SimpleQueue Objects.
                                                             (line   51)
* get_object_traceback() (in module tracemalloc): Functions<11>.
                                                             (line   12)
* get_objects() (in module gc):          gc — Garbage Collector interface.
                                                             (line   62)
* get_opcodes() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  125)
* get_option_group() (optparse.OptionParser method): Grouping Options.
                                                             (line  103)
* get_option() (optparse.OptionParser method): Querying and manipulating your option parser.
                                                             (line   37)
* get_origin() (in module typing):       Introspection helpers.
                                                             (line   59)
* get_original_bases() (in module types): Dynamic Type Creation.
                                                             (line   71)
* get_original_stdout() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  317)
* get_osfhandle() (in module msvcrt):    File Operations.    (line   58)
* get_output_charset() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  111)
* get_overloads() (in module typing):    Functions and decorators.
                                                             (line  286)
* get_pagesize() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  284)
* get_param() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  478)
* get_parameters() (symtable.Function method): Examining Symbol Tables.
                                                             (line  127)
* get_params() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  457)
* get_path_names() (in module sysconfig): Installation path functions.
                                                             (line   57)
* get_path() (in module sysconfig):      Installation path functions.
                                                             (line   62)
* get_paths() (in module sysconfig):     Installation path functions.
                                                             (line   92)
* get_payload() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  179)
* get_pid() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line    6)
* get_pipe_transport() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   10)
* get_platform() (in module sysconfig):  Other functions<3>. (line   11)
* get_poly() (in module turtle):         Special Turtle methods.
                                                             (line   17)
* get_preferred_scheme() (in module sysconfig): Installation path functions.
                                                             (line   24)
* get_protocol_members() (in module typing): Introspection helpers.
                                                             (line  100)
* get_protocol() (asyncio.BaseTransport method): Base Transport.
                                                             (line   88)
* get_proxy_response_headers() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  139)
* get_python_version() (in module sysconfig): Other functions<3>.
                                                             (line    6)
* get_ready() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line  148)
* get_referents() (in module gc):        gc — Garbage Collector interface.
                                                             (line  144)
* get_referrers() (in module gc):        gc — Garbage Collector interface.
                                                             (line  123)
* get_request() (socketserver.BaseServer method): Server Objects.
                                                             (line  134)
* get_resource_value() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  250)
* get_returncode() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   29)
* get_running_loop() (in module asyncio): Event loop.        (line   29)
* get_scheme_names() (in module sysconfig): Installation path functions.
                                                             (line    9)
* get_scheme() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  189)
* get_selection() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  110)
* get_sequences() (mailbox.MH method):   MH objects.         (line   56)
* get_sequences() (mailbox.MHMessage method): MHMessage objects.
                                                             (line   32)
* get_server_certificate() (in module ssl): Certificate handling.
                                                             (line   29)
* get_server() (multiprocessing.managers.BaseManager method): Managers.
                                                             (line   64)
* get_shapepoly() (in module turtle):    Appearance.         (line  169)
* get_source_segment() (in module ast):  ast Helpers.        (line  133)
* get_source() (importlib.abc.InspectLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  218)
* get_source() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  417)
* get_source() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  337)
* get_source() (importlib.machinery.SourcelessFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  274)
* get_source() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   66)
* get_stack() (asyncio.Task method):     Task object.        (line  121)
* get_stack() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  399)
* get_start_method() (in module multiprocessing): Miscellaneous<3>.
                                                             (line  100)
* get_starttag_text() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   32)
* get_stats_profile() (pstats.Stats method): The Stats Class.
                                                             (line  224)
* get_stats() (in module gc):            gc — Garbage Collector interface.
                                                             (line   73)
* get_stderr() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  128)
* get_stderr() (wsgiref.simple_server.WSGIRequestHandler method): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line  100)
* get_stdin() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  122)
* get_string() (mailbox.Mailbox method): Mailbox objects.    (line  174)
* get_string() (mailbox.mbox method):    mbox objects.       (line   50)
* get_subdir() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   47)
* get_symbols() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line  113)
* get_tabsize() (in module curses):      Functions<6>.       (line  462)
* get_task_factory() (asyncio.loop method): Creating futures and tasks.
                                                             (line   70)
* get_terminal_size() (in module os):    Querying the size of a terminal.
                                                             (line    8)
* get_terminal_size() (in module shutil): Querying the size of the output terminal.
                                                             (line    6)
* get_threshold() (in module gc):        gc — Garbage Collector interface.
                                                             (line  118)
* get_token() (shlex.shlex method):      shlex Objects.      (line    8)
* get_tool() (in module sys.monitoring): Registering and using tools.
                                                             (line   22)
* get_traceback_limit() (in module tracemalloc): Functions<11>.
                                                             (line   22)
* get_traced_memory() (in module tracemalloc): Functions<11>.
                                                             (line   32)
* get_tracemalloc_memory() (in module tracemalloc): Functions<11>.
                                                             (line   55)
* get_type_hints() (in module typing):   Introspection helpers.
                                                             (line    6)
* get_type() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   53)
* get_unixfrom() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  152)
* get_unixfrom() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  162)
* get_unpack_formats() (in module shutil): Archiving operations.
                                                             (line  189)
* get_unverified_chain() (ssl.SSLSocket method): SSL sockets.
                                                             (line  224)
* get_usage() (optparse.OptionParser method): Other methods. (line   22)
* get_value() (string.Formatter method): Custom string formatting.
                                                             (line   65)
* get_verified_chain() (ssl.SSLSocket method): SSL sockets.  (line  215)
* get_version() (optparse.OptionParser method): Printing a version string.
                                                             (line   34)
* get_visible() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   63)
* get_wch() (curses.window method):      Window Objects.     (line  242)
* get_write_buffer_limits() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   23)
* get_write_buffer_size() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   19)
* GET_YIELD_FROM_ITER (opcode):          Python Bytecode Instructions.
                                                             (line  218)
* get() (asyncio.Queue method):          Queue.              (line   39)
* get() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  223)
* get() (contextvars.Context method):    Manual Context Management.
                                                             (line  118)
* get() (contextvars.ContextVar method): Context Variables.  (line   30)
* get() (dict method):                   Mapping Types — dict.
                                                             (line  180)
* get() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  245)
* get() (email.message.Message method):  email message Message Representing an email message using the compat32 API.
                                                             (line  354)
* get() (in module webbrowser):          Command-line interface<4>.
                                                             (line   68)
* get() (mailbox.Mailbox method):        Mailbox objects.    (line  147)
* get() (multiprocessing.pool.AsyncResult method): Process Pools.
                                                             (line  202)
* get() (multiprocessing.Queue method):  Pipes and Queues.   (line  153)
* get() (multiprocessing.SimpleQueue method): Pipes and Queues.
                                                             (line  247)
* get() (queue.Queue method):            Queue Objects.      (line   46)
* get() (queue.SimpleQueue method):      SimpleQueue Objects.
                                                             (line   40)
* get() (tkinter.ttk.Combobox method):   ttk Combobox.       (line   15)
* get() (tkinter.ttk.Spinbox method):    ttk Spinbox.        (line    8)
* get() (types.MappingProxyType method): Standard Interpreter Types.
                                                             (line  260)
* get() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   64)
* getacl() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  106)
* getaddresses() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line   85)
* getaddrinfo() (asyncio.loop method):   DNS.                (line    6)
* getaddrinfo() (in module socket):      Other functions<2>. (line   16)
* getallocatedblocks() (in module sys):  sys — System-specific parameters and functions.
                                                             (line  726)
* getandroidapilevel() (in module sys):  sys — System-specific parameters and functions.
                                                             (line  746)
* getannotation() (imaplib.IMAP4 method): IMAP4 Objects.     (line  111)
* getargvalues() (in module inspect):    Classes and functions<2>.
                                                             (line   62)
* getasyncgenlocals() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line  100)
* getasyncgenstate() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line   47)
* getatime() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  174)
* getattr_static() (in module inspect):  Fetching attributes statically.
                                                             (line   16)
* getattrfunc (C type):                  Slot Type typedefs. (line   43)
* getAttribute() (xml.dom.Element method): Element Objects<2>.
                                                             (line   31)
* getAttributeNode() (xml.dom.Element method): Element Objects<2>.
                                                             (line   37)
* getAttributeNodeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   47)
* getAttributeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   41)
* getattrofunc (C type):                 Slot Type typedefs. (line   54)
* GetBase() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   31)
* getbegyx() (curses.window method):     Window Objects.     (line  226)
* getbkgd() (curses.window method):      Window Objects.     (line  230)
* getblocking() (socket.socket method):  Socket Objects.     (line  164)
* getboolean() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  257)
* getbuffer() (io.BytesIO method):       Buffered Streams.   (line   21)
* getbufferproc (C type):                Slot Type typedefs. (line  100)
* getByteStream() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   48)
* getcallargs() (in module inspect):     Classes and functions<2>.
                                                             (line   92)
* getcanvas() (in module turtle):        Settings and special methods.
                                                             (line   55)
* getch() (curses.window method):        Window Objects.     (line  235)
* getch() (in module msvcrt):            Console I/O.        (line   11)
* getCharacterStream() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   64)
* getche() (in module msvcrt):           Console I/O.        (line   26)
* getChild() (logging.Logger method):    Logger Objects.     (line  162)
* getChildren() (logging.Logger method): Logger Objects.     (line  174)
* getclasstree() (in module inspect):    Classes and functions<2>.
                                                             (line    6)
* getclosurevars() (in module inspect):  Classes and functions<2>.
                                                             (line  123)
* getcode() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   89)
* getcode() (urllib.response.addinfourl method): urllib response — Response classes used by urllib.
                                                             (line   45)
* getColumnNumber() (xml.sax.xmlreader.Locator method): Locator Objects.
                                                             (line    8)
* getcomments() (in module inspect):     Retrieving source code.
                                                             (line   18)
* getcompname() (wave.Wave_read method): Wave_read Objects.  (line   41)
* getcompname() (wave.Wave_write method): Wave_write Objects.
                                                             (line   84)
* getcomptype() (wave.Wave_read method): Wave_read Objects.  (line   36)
* getcomptype() (wave.Wave_write method): Wave_write Objects.
                                                             (line   80)
* getconfig() (sqlite3.Connection method): Connection objects.
                                                             (line  647)
* getContentHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   21)
* getcontext() (in module decimal):      Context objects.    (line   14)
* getcoroutinelocals() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line   92)
* getcoroutinestate() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line   28)
* getctime() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  190)
* getcwd() (in module os):               Files and Directories.
                                                             (line  293)
* getcwdb() (in module os):              Files and Directories.
                                                             (line  297)
* getdecoder() (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  116)
* getdefaultencoding() (in module sys):  sys — System-specific parameters and functions.
                                                             (line  757)
* getdefaultlocale() (in module locale): locale — Internationalization services.
                                                             (line  350)
* getdefaulttimeout() (in module socket): Other functions<2>.
                                                             (line  372)
* getdlopenflags() (in module sys):      sys — System-specific parameters and functions.
                                                             (line  762)
* getdoc() (in module inspect):          Retrieving source code.
                                                             (line    6)
* getDOMImplementation() (in module xml.dom): Module Contents<3>.
                                                             (line   17)
* getDTDHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   30)
* getEffectiveLevel() (logging.Logger method): Logger Objects.
                                                             (line  152)
* getegid() (in module os):              Process Parameters. (line  172)
* getElementsByTagName() (xml.dom.Document method): Document Objects.
                                                             (line   61)
* getElementsByTagName() (xml.dom.Element method): Element Objects<2>.
                                                             (line   14)
* getElementsByTagNameNS() (xml.dom.Document method): Document Objects.
                                                             (line   66)
* getElementsByTagNameNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   18)
* getencoder() (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  108)
* getencoding() (in module locale):      locale — Internationalization services.
                                                             (line  413)
* getEncoding() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   32)
* getEntityResolver() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   39)
* getenv() (in module os):               Process Parameters. (line  132)
* getenvb() (in module os):              Process Parameters. (line  147)
* getErrorHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   50)
* geteuid() (in module os):              Process Parameters. (line  180)
* getEvent() (xml.dom.pulldom.DOMEventStream method): DOMEventStream Objects.
                                                             (line   11)
* getEventCategory() (logging.handlers.NTEventLogHandler method): NTEventLogHandler.
                                                             (line   43)
* getEventType() (logging.handlers.NTEventLogHandler method): NTEventLogHandler.
                                                             (line   49)
* getException() (xml.sax.SAXException method): SAXException Objects.
                                                             (line   13)
* getFeature() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   69)
* getfile() (in module inspect):         Retrieving source code.
                                                             (line   27)
* getFilesToDelete() (logging.handlers.TimedRotatingFileHandler method): TimedRotatingFileHandler.
                                                             (line  115)
* getfilesystemencodeerrors() (in module sys): sys — System-specific parameters and functions.
                                                             (line  802)
* getfilesystemencoding() (in module sys): sys — System-specific parameters and functions.
                                                             (line  771)
* getfirstweekday() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   47)
* getfloat() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  250)
* getfqdn() (in module socket):          Other functions<2>. (line   98)
* getframeinfo() (in module inspect):    The interpreter stack.
                                                             (line  123)
* getframerate() (wave.Wave_read method): Wave_read Objects. (line   28)
* getframerate() (wave.Wave_write method): Wave_write Objects.
                                                             (line   60)
* getfullargspec() (in module inspect):  Classes and functions<2>.
                                                             (line   17)
* getgeneratorlocals() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line   72)
* getgeneratorstate() (in module inspect): Current State of Generators Coroutines and Asynchronous Generators.
                                                             (line   12)
* getgid() (in module os):               Process Parameters. (line  186)
* getgrall() (in module grp):            grp — The group database.
                                                             (line   58)
* getgrgid() (in module grp):            grp — The group database.
                                                             (line   44)
* getgrnam() (in module grp):            grp — The group database.
                                                             (line   53)
* getgrouplist() (in module os):         Process Parameters. (line  195)
* getgroups() (in module os):            Process Parameters. (line  206)
* getHandlerByName() (in module logging): Module-Level Functions.
                                                             (line  183)
* getHandlerNames() (in module logging): Module-Level Functions.
                                                             (line  190)
* getheader() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   24)
* getheaders() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   32)
* gethostbyaddr() (in module socket):    Process Parameters. (line  544)
* gethostbyaddr() (in module socket) <1>: Other functions<2>.
                                                             (line  155)
* gethostbyname_ex() (in module socket): Other functions<2>. (line  125)
* gethostbyname() (in module socket):    Other functions<2>. (line  110)
* gethostname() (in module socket):      Process Parameters. (line  544)
* gethostname() (in module socket) <1>:  Other functions<2>. (line  142)
* getincrementaldecoder() (in module codecs): codecs — Codec registry and base classes.
                                                             (line  132)
* getincrementalencoder() (in module codecs): codecs — Codec registry and base classes.
                                                             (line  124)
* getinfo() (zipfile.ZipFile method):    ZipFile objects.    (line  111)
* getinnerframes() (in module inspect):  The interpreter stack.
                                                             (line  146)
* GetInputContext() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   36)
* getint() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  243)
* getitem() (in module operator):        operator — Standard operators as functions.
                                                             (line  196)
* getiterfunc (C type):                  Slot Type typedefs. (line   88)
* getitimer() (in module signal):        Module contents<3>. (line  466)
* getkey() (curses.window method):       Window Objects.     (line  250)
* GetLastError() (in module ctypes):     Utility functions.  (line  143)
* getLength() (xml.sax.xmlreader.Attributes method): The Attributes Interface.
                                                             (line   11)
* getLevelName() (in module logging):    Module-Level Functions.
                                                             (line  150)
* getLevelNamesMapping() (in module logging): Module-Level Functions.
                                                             (line  141)
* getlimit() (sqlite3.Connection method): Connection objects.
                                                             (line  591)
* getline() (in module linecache):       linecache — Random access to text lines.
                                                             (line   23)
* getLineNumber() (xml.sax.xmlreader.Locator method): Locator Objects.
                                                             (line   12)
* getloadavg() (in module os):           Miscellaneous System Information.
                                                             (line   52)
* getlocale() (in module locale):        locale — Internationalization services.
                                                             (line  377)
* getLogger() (in module logging):       Module-Level Functions.
                                                             (line    9)
* getLoggerClass() (in module logging):  Module-Level Functions.
                                                             (line   23)
* getlogin() (in module os):             Process Parameters. (line  229)
* getLogRecordFactory() (in module logging): Module-Level Functions.
                                                             (line   34)
* getMandatoryRelease() (__future__._Feature method): Module Contents<4>.
                                                             (line   74)
* getmark() (wave.Wave_read method):     Wave_read Objects.  (line   72)
* getmarkers() (wave.Wave_read method):  Wave_read Objects.  (line   64)
* getmaxyx() (curses.window method):     Window Objects.     (line  257)
* getmember() (tarfile.TarFile method):  TarFile Objects.    (line  102)
* getmembers_static() (in module inspect): Types and members.
                                                             (line  338)
* getmembers() (in module inspect):      Types and members.  (line  325)
* getmembers() (tarfile.TarFile method): TarFile Objects.    (line  110)
* getMessage() (logging.LogRecord method): LogRecord Objects.
                                                             (line   64)
* getMessage() (xml.sax.SAXException method): SAXException Objects.
                                                             (line    9)
* getMessageID() (logging.handlers.NTEventLogHandler method): NTEventLogHandler.
                                                             (line   60)
* getmodule() (in module inspect):       Retrieving source code.
                                                             (line   33)
* getmodulename() (in module inspect):   Types and members.  (line  353)
* getmouse() (in module curses):         Functions<6>.       (line  145)
* getmro() (in module inspect):          Classes and functions<2>.
                                                             (line   84)
* getmtime() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  181)
* getName() (threading.Thread method):   Thread objects.     (line  157)
* getNameByQName() (xml.sax.xmlreader.AttributesNS method): The AttributesNS Interface.
                                                             (line   16)
* getnameinfo() (asyncio.loop method):   DNS.                (line   11)
* getnameinfo() (in module socket):      Other functions<2>. (line  171)
* getnames() (tarfile.TarFile method):   TarFile Objects.    (line  116)
* getNames() (xml.sax.xmlreader.Attributes method): The Attributes Interface.
                                                             (line   15)
* getnchannels() (wave.Wave_read method): Wave_read Objects. (line   19)
* getnchannels() (wave.Wave_write method): Wave_write Objects.
                                                             (line   41)
* getnframes() (wave.Wave_read method):  Wave_read Objects.  (line   32)
* getnframes() (wave.Wave_write method): Wave_write Objects. (line   71)
* getnode() (in module uuid):            uuid — UUID objects according to RFC 4122.
                                                             (line  161)
* getobjects() (in module sys):          sys — System-specific parameters and functions.
                                                             (line  911)
* getopt() (in module getopt):           getopt — C-style parser for command line options.
                                                             (line   33)
* GetoptError:                           getopt — C-style parser for command line options.
                                                             (line   82)
* getOptionalRelease() (__future__._Feature method): Module Contents<4>.
                                                             (line   69)
* getouterframes() (in module inspect):  The interpreter stack.
                                                             (line  131)
* getoutput() (in module subprocess):    Legacy Shell Invocation Functions.
                                                             (line   45)
* getpagesize() (in module resource):    Resource Usage.     (line  101)
* getparams() (wave.Wave_read method):   Wave_read Objects.  (line   46)
* getparams() (wave.Wave_write method):  Wave_write Objects. (line   94)
* getparyx() (curses.window method):     Window Objects.     (line  261)
* getpass() (in module getpass):         getpass — Portable password input.
                                                             (line   17)
* GetPassWarning:                        getpass — Portable password input.
                                                             (line   34)
* getpeercert() (ssl.SSLSocket method):  SSL sockets.        (line  146)
* getpeername() (socket.socket method):  Socket Objects.     (line  134)
* getpen() (in module turtle):           Special Turtle methods.
                                                             (line   40)
* getpgid() (in module os):              Process Parameters. (line  240)
* getpgrp() (in module os):              Process Parameters. (line  248)
* getpid() (in module os):               Process Parameters. (line  254)
* getpos() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   28)
* getppid() (in module os):              Process Parameters. (line  261)
* getpreferredencoding() (in module locale): locale — Internationalization services.
                                                             (line  389)
* getpriority() (in module os):          Process Parameters. (line  272)
* getprofile() (in module sys):          sys — System-specific parameters and functions.
                                                             (line  936)
* getprofile() (in module threading):    Reference<2>.       (line  152)
* getProperty() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   83)
* getprotobyname() (in module socket):   Other functions<2>. (line  191)
* getproxies() (in module urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  167)
* getPublicId() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   10)
* getPublicId() (xml.sax.xmlreader.Locator method): Locator Objects.
                                                             (line   16)
* getpwall() (in module pwd):            pwd — The password database.
                                                             (line   63)
* getpwnam() (in module pwd):            pwd — The password database.
                                                             (line   59)
* getpwuid() (in module pwd):            pwd — The password database.
                                                             (line   55)
* getQNameByName() (xml.sax.xmlreader.AttributesNS method): The AttributesNS Interface.
                                                             (line   20)
* getQNames() (xml.sax.xmlreader.AttributesNS method): The AttributesNS Interface.
                                                             (line   24)
* getquota() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  116)
* getquotaroot() (imaplib.IMAP4 method): IMAP4 Objects.      (line  121)
* getrandbits() (in module random):      Functions for integers.
                                                             (line   37)
* getrandbits() (random.Random method):  Alternative Generator.
                                                             (line   41)
* getrandom() (in module os):            Random numbers<2>.  (line    6)
* getreader() (in module codecs):        codecs — Codec registry and base classes.
                                                             (line  140)
* getrecursionlimit() (in module sys):   sys — System-specific parameters and functions.
                                                             (line  843)
* getrefcount() (in module sys):         sys — System-specific parameters and functions.
                                                             (line  827)
* GetReparseDeferralEnabled() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  110)
* getresgid() (in module os):            Process Parameters. (line  318)
* getresponse() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line   80)
* getresuid() (in module os):            Process Parameters. (line  309)
* getrlimit() (in module resource):      Resource Limits.    (line   24)
* getroot() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   36)
* getrusage() (in module resource):      Resource Usage.     (line    8)
* getsampwidth() (wave.Wave_read method): Wave_read Objects. (line   24)
* getsampwidth() (wave.Wave_write method): Wave_write Objects.
                                                             (line   49)
* getscreen() (in module turtle):        Special Turtle methods.
                                                             (line   51)
* getservbyname() (in module socket):    Other functions<2>. (line  202)
* getservbyport() (in module socket):    Other functions<2>. (line  213)
* GetSetDescriptorType (in module types): Standard Interpreter Types.
                                                             (line  200)
* getshapes() (in module turtle):        Settings and special methods.
                                                             (line   64)
* getsid() (in module os):               Process Parameters. (line  502)
* getsignal() (in module signal):        Module contents<3>. (line  314)
* getsitepackages() (in module site):    Module contents<6>. (line   58)
* getsize() (in module os.path):         os path — Common pathname manipulations.
                                                             (line  201)
* getsizeof() (in module sys):           sys — System-specific parameters and functions.
                                                             (line  850)
* getsockname() (socket.socket method):  Socket Objects.     (line  142)
* getsockopt() (socket.socket method):   Socket Objects.     (line  149)
* getsource() (in module inspect):       Retrieving source code.
                                                             (line   59)
* getsourcefile() (in module inspect):   Retrieving source code.
                                                             (line   38)
* getsourcelines() (in module inspect):  Retrieving source code.
                                                             (line   45)
* getstate() (codecs.IncrementalDecoder method): IncrementalDecoder Objects.
                                                             (line   43)
* getstate() (codecs.IncrementalEncoder method): IncrementalEncoder Objects.
                                                             (line   42)
* getstate() (in module random):         Bookkeeping functions.
                                                             (line   32)
* getstate() (random.Random method):     Alternative Generator.
                                                             (line   23)
* getstatusoutput() (in module subprocess): Legacy Shell Invocation Functions.
                                                             (line   11)
* getstr() (curses.window method):       Window Objects.     (line  267)
* getSubject() (logging.handlers.SMTPHandler method): SMTPHandler.
                                                             (line   38)
* getswitchinterval() (in module sys):   sys — System-specific parameters and functions.
                                                             (line  872)
* getSystemId() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   18)
* getSystemId() (xml.sax.xmlreader.Locator method): Locator Objects.
                                                             (line   20)
* getsyx() (in module curses):           Functions<6>.       (line  163)
* gettarinfo() (tarfile.TarFile method): TarFile Objects.    (line  301)
* gettempdir() (in module tempfile):     tempfile — Generate temporary files and directories.
                                                             (line  318)
* gettempdirb() (in module tempfile):    tempfile — Generate temporary files and directories.
                                                             (line  350)
* gettempprefix() (in module tempfile):  tempfile — Generate temporary files and directories.
                                                             (line  356)
* gettempprefixb() (in module tempfile): tempfile — Generate temporary files and directories.
                                                             (line  361)
* getter (C type):                       Defining Getters and Setters.
                                                             (line   33)
* getTestCaseNames() (unittest.TestLoader method): Loading and running tests.
                                                             (line  110)
* gettext() (gettext.GNUTranslations method): The GNUTranslations class.
                                                             (line   38)
* gettext() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   35)
* gettext() (in module gettext):         GNU gettext API.    (line   32)
* gettext() (in module locale):          Access to message catalogs.
                                                             (line    6)
* gettimeout() (socket.socket method):   Socket Objects.     (line  173)
* gettrace() (in module sys):            sys — System-specific parameters and functions.
                                                             (line  940)
* gettrace() (in module threading):      Reference<2>.       (line  130)
* getturtle() (in module turtle):        Special Turtle methods.
                                                             (line   40)
* getType() (xml.sax.xmlreader.Attributes method): The Attributes Interface.
                                                             (line   19)
* getuid() (in module os):               Process Parameters. (line  327)
* getunicodeinternedsize() (in module sys): sys — System-specific parameters and functions.
                                                             (line  740)
* geturl() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   79)
* geturl() (urllib.parse.urllib.parse.SplitResult method): Structured Parse Results.
                                                             (line   12)
* geturl() (urllib.response.addinfourl method): urllib response — Response classes used by urllib.
                                                             (line   30)
* getuser() (in module getpass):         getpass — Portable password input.
                                                             (line   39)
* getuserbase() (in module site):        Module contents<6>. (line   64)
* getusersitepackages() (in module site): Module contents<6>.
                                                             (line   72)
* getvalue() (io.BytesIO method):        Buffered Streams.   (line   38)
* getvalue() (io.StringIO method):       Text I/O<2>.        (line  264)
* getValue() (xml.sax.xmlreader.Attributes method): The Attributes Interface.
                                                             (line   24)
* getValueByQName() (xml.sax.xmlreader.AttributesNS method): The AttributesNS Interface.
                                                             (line   12)
* getwch() (in module msvcrt):           Console I/O.        (line   21)
* getwche() (in module msvcrt):          Console I/O.        (line   31)
* getweakrefcount() (in module weakref): weakref — Weak references.
                                                             (line  154)
* getweakrefs() (in module weakref):     weakref — Weak references.
                                                             (line  159)
* getwelcome() (ftplib.FTP method):      FTP objects.        (line  120)
* getwelcome() (poplib.POP3 method):     POP3 Objects.       (line   20)
* getwin() (in module curses):           Functions<6>.       (line  169)
* getwindowsversion() (in module sys):   sys — System-specific parameters and functions.
                                                             (line  950)
* getwriter() (in module codecs):        codecs — Codec registry and base classes.
                                                             (line  148)
* getxattr() (in module os):             Linux extended attributes.
                                                             (line   10)
* getyx() (curses.window method):        Window Objects.     (line  278)
* gid (tarfile.TarInfo attribute):       TarInfo Objects.    (line  113)
* GIL:                                   Glossary.           (line  720)
* glob() (in module glob):               glob — Unix style pathname pattern expansion.
                                                             (line   29)
* glob() (pathlib.Path method):          Reading directories.
                                                             (line   30)
* Global (class in ast):                 Function and class definitions.
                                                             (line  145)
* global interpreter lock:               Thread State and the Global Interpreter Lock.
                                                             (line    6)
* global interpreter lock <1>:           Glossary.           (line  724)
* global state:                          Glossary.           (line  748)
* global_enum() (in module enum):        Utilities and decorators.
                                                             (line   92)
* global; name; binding:                 The global statement.
                                                             (line    6)
* global; namespace:                     Special read-only attributes.
                                                             (line    6)
* globs (doctest.DocTest attribute):     DocTest Objects.    (line   21)
* gmtime() (in module time):             Functions<5>.       (line  139)
* gname (tarfile.TarInfo attribute):     TarInfo Objects.    (line  129)
* GNOME:                                 The Catalog constructor.
                                                             (line    6)
* GNU_FORMAT (in module tarfile):        tarfile — Read and write tar archive files.
                                                             (line  330)
* gnu_getopt() (in module getopt):       getopt — C-style parser for command line options.
                                                             (line   70)
* GNUTranslations (class in gettext):    The GNUTranslations class.
                                                             (line   33)
* GNUTYPE_LONGLINK (in module tarfile):  tarfile — Read and write tar archive files.
                                                             (line  314)
* GNUTYPE_LONGNAME (in module tarfile):  tarfile — Read and write tar archive files.
                                                             (line  310)
* GNUTYPE_SPARSE (in module tarfile):    tarfile — Read and write tar archive files.
                                                             (line  318)
* go() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  114)
* got (doctest.DocTestFailure attribute): Debugging.         (line  204)
* goto() (in module turtle):             Turtle motion.      (line   74)
* grammar:                               Notation.           (line    6)
* grantpt() (in module os):              File Descriptor Operations.
                                                             (line  248)
* Graphical User Interface:              Graphical user interfaces with Tk.
                                                             (line    6)
* GREATER (in module token):             token — Constants used with Python parse trees.
                                                             (line  218)
* GREATEREQUAL (in module token):        token — Constants used with Python parse trees.
                                                             (line  245)
* Greenwich Mean Time:                   time — Time access and conversions.
                                                             (line   39)
* GRND_NONBLOCK (in module os):          Random numbers<2>.  (line   76)
* GRND_RANDOM (in module os):            Random numbers<2>.  (line   89)
* Group (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  456)
* group() (pathlib.Path method):         Permissions and ownership.
                                                             (line   21)
* group() (re.Match method):             Match Objects.      (line   36)
* groupby() (in module itertools):       Itertool Functions. (line  306)
* groupdict() (re.Match method):         Match Objects.      (line  135)
* groupindex (re.Pattern attribute):     Regular Expression Objects.
                                                             (line  118)
* grouping:                              Indentation.        (line    6)
* groups (email.headerregistry.AddressHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  187)
* groups (re.Pattern attribute):         Regular Expression Objects.
                                                             (line  114)
* groups() (re.Match method):            Match Objects.      (line  112)
* GS (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line  111)
* Gt (class in ast):                     Expressions<2>.     (line  108)
* gt() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* GtE (class in ast):                    Expressions<2>.     (line  108)
* guard:                                 Guards.             (line    6)
* guess_all_extensions() (in module mimetypes): mimetypes — Map filenames to MIME types.
                                                             (line   63)
* guess_all_extensions() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line   72)
* guess_extension() (in module mimetypes): mimetypes — Map filenames to MIME types.
                                                             (line   75)
* guess_extension() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line   55)
* guess_file_type() (in module mimetypes): mimetypes — Map filenames to MIME types.
                                                             (line   54)
* guess_file_type() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line   65)
* guess_scheme() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line   14)
* guess_type() (in module mimetypes):    mimetypes — Map filenames to MIME types.
                                                             (line   23)
* guess_type() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line   60)
* GUI:                                   Graphical user interfaces with Tk.
                                                             (line    6)
* gzip command line option; -best:       Command-line options.
                                                             (line   14)
* gzip command line option; -d:          Command-line options.
                                                             (line   18)
* gzip command line option; -decompress: Command-line options.
                                                             (line   18)
* gzip command line option; -fast:       Command-line options.
                                                             (line   10)
* gzip command line option; -h:          Command-line options.
                                                             (line   22)
* gzip command line option; -help:       Command-line options.
                                                             (line   22)
* gzip command line option; file:        Command-line options.
                                                             (line    6)
* GzipFile (class in gzip):              gzip — Support for gzip files.
                                                             (line   70)
* halfdelay() (in module curses):        Functions<6>.       (line  211)
* Handle (class in asyncio):             Callback handles.   (line    6)
* handle an exception:                   Exceptions<2>.      (line    6)
* handle_charref() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   91)
* handle_comment() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line  100)
* handle_data() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   79)
* handle_decl() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line  113)
* handle_defect() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  234)
* handle_endtag() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   64)
* handle_entityref() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   84)
* handle_error() (socketserver.BaseServer method): Server Objects.
                                                             (line  140)
* handle_expect_100() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  203)
* handle_one_request() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  197)
* handle_pi() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line  121)
* handle_request() (socketserver.BaseServer method): Server Objects.
                                                             (line   21)
* handle_request() (xmlrpc.server.CGIXMLRPCRequestHandler method): CGIXMLRPCRequestHandler.
                                                             (line   50)
* handle_startendtag() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   71)
* handle_starttag() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   45)
* handle_timeout() (socketserver.BaseServer method): Server Objects.
                                                             (line  150)
* handle() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  190)
* handle() (logging.Handler method):     Handler Objects.    (line   83)
* handle() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   66)
* handle() (logging.Logger method):      Logger Objects.     (line  365)
* handle() (logging.NullHandler method): NullHandler.        (line   20)
* handle() (socketserver.BaseRequestHandler method): Request Handler Objects.
                                                             (line   20)
* handle() (wsgiref.simple_server.WSGIRequestHandler method): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line  105)
* handleError() (logging.Handler method): Handler Objects.   (line   90)
* handleError() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   33)
* Handler (class in logging):            Handler Objects.    (line   11)
* Handlers (class in signal):            Module contents<3>. (line   24)
* handlers (logging.Logger attribute):   Logger Objects.     (line   87)
* hardlink_to() (pathlib.Path method):   Creating files and directories.
                                                             (line   73)
* harmonic_mean() (in module statistics): Function details.  (line   97)
* HAS_ALPN (in module ssl):              Constants<9>.       (line  382)
* has_children() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   98)
* has_colors() (in module curses):       Functions<6>.       (line  176)
* has_default() (typing.ParamSpec method): Building generic types and type aliases.
                                                             (line  434)
* has_default() (typing.TypeVar method): Building generic types and type aliases.
                                                             (line  201)
* has_default() (typing.TypeVarTuple method): Building generic types and type aliases.
                                                             (line  333)
* has_dualstack_ipv6() (in module socket): Creating sockets. (line  151)
* HAS_ECDH (in module ssl):              Constants<9>.       (line  398)
* has_extended_color_support() (in module curses): Functions<6>.
                                                             (line  181)
* has_extn() (smtplib.SMTP method):      SMTP Objects.       (line   85)
* has_header() (csv.Sniffer method):     Module Contents<2>. (line  241)
* has_header() (urllib.request.Request method): Request Objects.
                                                             (line   94)
* has_ic() (in module curses):           Functions<6>.       (line  192)
* has_il() (in module curses):           Functions<6>.       (line  199)
* has_ipv6 (in module socket):           Constants<8>.       (line  293)
* has_key() (in module curses):          Functions<6>.       (line  206)
* has_location (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  435)
* HAS_NEVER_CHECK_COMMON_NAME (in module ssl): Constants<9>. (line  390)
* has_nonstandard_attr() (http.cookiejar.Cookie method): Cookie Objects<2>.
                                                             (line   96)
* HAS_NPN (in module ssl):               Constants<9>.       (line  413)
* has_option() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  141)
* has_option() (optparse.OptionParser method): Querying and manipulating your option parser.
                                                             (line   42)
* HAS_PSK (in module ssl):               Constants<9>.       (line  465)
* has_section() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  132)
* HAS_SNI (in module ssl):               Constants<9>.       (line  406)
* HAS_SSLv2 (in module ssl):             Constants<9>.       (line  423)
* HAS_SSLv3 (in module ssl):             Constants<9>.       (line  430)
* has_ticket (ssl.SSLSession attribute): SSL session.        (line   20)
* HAS_TLSv1 (in module ssl):             Constants<9>.       (line  437)
* HAS_TLSv1_1 (in module ssl):           Constants<9>.       (line  444)
* HAS_TLSv1_2 (in module ssl):           Constants<9>.       (line  451)
* HAS_TLSv1_3 (in module ssl):           Constants<9>.       (line  458)
* hasarg (in module dis):                Opcode collections. (line   25)
* hasAttribute() (xml.dom.Element method): Element Objects<2>.
                                                             (line   22)
* hasAttributeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   26)
* hasAttributes() (xml.dom.Node method): Node Objects.       (line   94)
* hasChildNodes() (xml.dom.Node method): Node Objects.       (line   98)
* hascompare (in module dis):            Opcode collections. (line   58)
* hasconst (in module dis):              Opcode collections. (line   31)
* hasexc (in module dis):                Opcode collections. (line   62)
* hasFeature() (xml.dom.DOMImplementation method): DOMImplementation Objects.
                                                             (line   11)
* hasfree (in module dis):               Opcode collections. (line   35)
* hash character:                        Comments.           (line    6)
* hash_bits (sys.hash_info attribute):   sys — System-specific parameters and functions.
                                                             (line 1058)
* hash_info (in module sys):             sys — System-specific parameters and functions.
                                                             (line 1027)
* hash_randomization (sys.flags attribute): sys — System-specific parameters and functions.
                                                             (line  563)
* hash-based pyc:                        Glossary.           (line  756)
* hash.block_size (in module hashlib):   Hash Objects.       (line   13)
* hash.digest_size (in module hashlib):  Hash Objects.       (line    9)
* hashable:                              Dictionary displays.
                                                             (line   37)
* hashable <1>:                          Glossary.           (line  762)
* Hashable (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   11)
* Hashable (class in typing):            Aliases to other ABCs in collections abc.
                                                             (line   53)
* hasHandlers() (logging.Logger method): Logger Objects.     (line  380)
* hashfunc (C type):                     Slot Type typedefs. (line   79)
* hasjabs (in module dis):               Opcode collections. (line   75)
* hasjrel (in module dis):               Opcode collections. (line   68)
* hasjump (in module dis):               Opcode collections. (line   47)
* haslocal (in module dis):              Opcode collections. (line   54)
* hasname (in module dis):               Opcode collections. (line   43)
* HAVE_ARGUMENT (opcode):                Python Bytecode Instructions.
                                                             (line 1272)
* HAVE_CONTEXTVAR (in module decimal):   Constants<4>.       (line   32)
* HAVE_DOCSTRINGS (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  162)
* HAVE_THREADS (in module decimal):      Constants<4>.       (line   25)
* HCI_DATA_DIR (in module socket):       Constants<8>.       (line  306)
* HCI_FILTER (in module socket):         Constants<8>.       (line  306)
* HCI_TIME_STAMP (in module socket):     Constants<8>.       (line  306)
* Header (class in email.header):        email header Internationalized headers.
                                                             (line   59)
* header_encode_lines() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  125)
* header_encode() (email.charset.Charset method): email charset Representing character sets.
                                                             (line  118)
* header_encoding (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   59)
* header_factory (email.policy.EmailPolicy attribute): email policy Policy Objects.
                                                             (line  407)
* header_fetch_parse() (email.policy.Compat32 method): email policy Policy Objects.
                                                             (line  593)
* header_fetch_parse() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  457)
* header_fetch_parse() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  318)
* header_items() (urllib.request.Request method): Request Objects.
                                                             (line  125)
* header_max_count() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  434)
* header_max_count() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  259)
* header_offset (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  146)
* header_source_parse() (email.policy.Compat32 method): email policy Policy Objects.
                                                             (line  581)
* header_source_parse() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  440)
* header_source_parse() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  281)
* header_store_parse() (email.policy.Compat32 method): email policy Policy Objects.
                                                             (line  589)
* header_store_parse() (email.policy.EmailPolicy method): email policy Policy Objects.
                                                             (line  448)
* header_store_parse() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  302)
* HeaderDefect:                          email errors Exception and Defect classes.
                                                             (line   60)
* HeaderError:                           tarfile — Read and write tar archive files.
                                                             (line  224)
* HeaderParseError:                      email errors Exception and Defect classes.
                                                             (line   26)
* HeaderParser (class in email.parser):  Parser API.         (line  106)
* HeaderRegistry (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  298)
* Headers (class in wsgiref.headers):    wsgiref headers – WSGI response header tools.
                                                             (line    9)
* headers (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   56)
* headers (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  108)
* headers (urllib.error.HTTPError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   53)
* headers (urllib.response.addinfourl attribute): urllib response — Response classes used by urllib.
                                                             (line   19)
* headers (xmlrpc.client.ProtocolError attribute): ProtocolError Objects.
                                                             (line   25)
* HeaderWriteError:                      email errors Exception and Defect classes.
                                                             (line   50)
* heading() (in module turtle):          Tell Turtle’s state.
                                                             (line   58)
* heading() (tkinter.ttk.Treeview method): ttk Treeview.     (line   99)
* heapify() (in module heapq):           heapq — Heap queue algorithm.
                                                             (line   40)
* heapmin() (in module msvcrt):          Other Functions.    (line    6)
* heappop() (in module heapq):           heapq — Heap queue algorithm.
                                                             (line   49)
* heappush() (in module heapq):          heapq — Heap queue algorithm.
                                                             (line   44)
* heappushpop() (in module heapq):       heapq — Heap queue algorithm.
                                                             (line   56)
* heapreplace() (in module heapq):       heapq — Heap queue algorithm.
                                                             (line   63)
* helo_resp (smtplib.SMTP attribute):    SMTP Objects.       (line  352)
* helo() (smtplib.SMTP method):          SMTP Objects.       (line   47)
* help (optparse.Option attribute):      Option attributes.  (line   80)
* help (pdb command):                    Debugger commands.  (line   73)
* help; online:                          pydoc — Documentation generator and online help system.
                                                             (line    8)
* herror:                                Exceptions<15>.     (line   13)
* hex (uuid.UUID attribute):             uuid — UUID objects according to RFC 4122.
                                                             (line  128)
* hex() (bytearray method):              Bytearray Objects.  (line   54)
* hex() (bytes method):                  Bytes Objects.      (line   79)
* hex() (float method):                  Additional Methods on Float.
                                                             (line   33)
* hex() (memoryview method):             Memory Views.       (line  187)
* hexadecimal literal:                   Numeric literals.   (line    6)
* hexadecimal; literals:                 Numeric Types — int float complex.
                                                             (line   19)
* hexdigest() (hashlib.hash method):     Hash Objects.       (line   44)
* hexdigest() (hashlib.shake method):    SHAKE variable length digests.
                                                             (line   21)
* hexdigest() (hmac.HMAC method):        hmac — Keyed-Hashing for Message Authentication.
                                                             (line   73)
* hexdigits (in module string):          String constants.   (line   28)
* hexlify() (in module binascii):        binascii — Convert between binary and ASCII.
                                                             (line  114)
* hexversion (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1076)
* hidden() (curses.panel.Panel method):  Panel Objects.      (line   25)
* hide_cookie2 (http.cookiejar.CookiePolicy attribute): CookiePolicy Objects.
                                                             (line   75)
* hide() (curses.panel.Panel method):    Panel Objects.      (line   30)
* hide() (tkinter.ttk.Notebook method):  ttk Notebook.       (line   23)
* hideturtle() (in module turtle):       Visibility.         (line    6)
* HierarchyRequestErr:                   Exceptions<20>.     (line   29)
* HIGH_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line   82)
* HIGHEST_PROTOCOL (in module pickle):   Module Interface.   (line   14)
* hits (bdb.Breakpoint attribute):       bdb — Debugger framework.
                                                             (line  120)
* HKEY_CLASSES_ROOT (in module winreg):  HKEY_* Constants.   (line    6)
* HKEY_CURRENT_CONFIG (in module winreg): HKEY_* Constants.  (line   38)
* HKEY_CURRENT_USER (in module winreg):  HKEY_* Constants.   (line   12)
* HKEY_DYN_DATA (in module winreg):      HKEY_* Constants.   (line   43)
* HKEY_LOCAL_MACHINE (in module winreg): HKEY_* Constants.   (line   19)
* HKEY_PERFORMANCE_DATA (in module winreg): HKEY_* Constants.
                                                             (line   31)
* HKEY_USERS (in module winreg):         HKEY_* Constants.   (line   25)
* hline() (curses.window method):        Window Objects.     (line  283)
* hls_to_rgb() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   40)
* HMAC (class in hmac):                  hmac — Keyed-Hashing for Message Authentication.
                                                             (line   47)
* HOME:                                  os path<5>.         (line   15)
* HOME <1>:                              Changes in the Python API<5>.
                                                             (line  118)
* HOME <2>:                              Windows<46>.        (line   15)
* HOME <3>:                              Windows<46>.        (line   18)
* HOME <4>:                              os path — Common pathname manipulations.
                                                             (line  143)
* HOME <5>:                              os path — Common pathname manipulations.
                                                             (line  160)
* HOME <6>:                              Tkinter Modules.    (line   64)
* home() (in module turtle):             Turtle motion.      (line  195)
* home() (pathlib.Path class method):    Expanding and resolving paths.
                                                             (line    6)
* HOMEDRIVE:                             os path — Common pathname manipulations.
                                                             (line  150)
* HOMEPATH:                              os path — Common pathname manipulations.
                                                             (line  150)
* hook_compressed() (in module fileinput): fileinput — Iterate over lines from multiple input streams.
                                                             (line  195)
* hook_encoded() (in module fileinput):  fileinput — Iterate over lines from multiple input streams.
                                                             (line  215)
* hooks; import:                         Import hooks.       (line    6)
* hooks; meta:                           Import hooks.       (line    6)
* hooks; path:                           Import hooks.       (line    6)
* host (urllib.request.Request attribute): Request Objects.  (line   25)
* hostmask (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   97)
* hostmask (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  313)
* hostname_checks_common_name (ssl.SSLContext attribute): SSL contexts.
                                                             (line  612)
* hosts (netrc.netrc attribute):         netrc Objects.      (line   23)
* hosts() (ipaddress.IPv4Network method): Network objects.   (line  136)
* hosts() (ipaddress.IPv6Network method): Network objects.   (line  331)
* hour (datetime.datetime attribute):    datetime Objects.   (line  317)
* hour (datetime.time attribute):        time Objects.       (line   50)
* HRESULT (class in ctypes):             Fundamental data types<2>.
                                                             (line  213)
* hStdError (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   41)
* hStdInput (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   27)
* hStdOutput (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   34)
* hsv_to_rgb() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   48)
* HT (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   48)
* ht() (in module turtle):               Visibility.         (line    6)
* HTML:                                  html parser — Simple HTML and XHTML parser.
                                                             (line    8)
* HTML <1>:                              urllib request Restrictions.
                                                             (line   29)
* html5 (in module html.entities):       html entities — Definitions of HTML general entities.
                                                             (line   14)
* HTMLCalendar (class in calendar):      calendar — General calendar-related functions.
                                                             (line  222)
* HtmlDiff (class in difflib):           difflib — Helpers for computing deltas.
                                                             (line   82)
* HTMLParser (class in html.parser):     html parser — Simple HTML and XHTML parser.
                                                             (line   14)
* htonl() (in module socket):            Other functions<2>. (line  241)
* htons() (in module socket):            Other functions<2>. (line  248)
* HTTP (in module email.policy):         email policy Policy Objects.
                                                             (line  524)
* http_error_301() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   35)
* http_error_302() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   42)
* http_error_303() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   48)
* http_error_307() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   54)
* http_error_308() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   61)
* http_error_401() (urllib.request.HTTPBasicAuthHandler method): HTTPBasicAuthHandler Objects.
                                                             (line    6)
* http_error_401() (urllib.request.HTTPDigestAuthHandler method): HTTPDigestAuthHandler Objects.
                                                             (line    6)
* http_error_407() (urllib.request.ProxyBasicAuthHandler method): ProxyBasicAuthHandler Objects.
                                                             (line    6)
* http_error_407() (urllib.request.ProxyDigestAuthHandler method): ProxyDigestAuthHandler Objects.
                                                             (line    6)
* http_error_auth_reqed() (urllib.request.AbstractBasicAuthHandler method): AbstractBasicAuthHandler Objects.
                                                             (line    6)
* http_error_auth_reqed() (urllib.request.AbstractDigestAuthHandler method): AbstractDigestAuthHandler Objects.
                                                             (line    6)
* http_error_default() (urllib.request.BaseHandler method): BaseHandler Objects.
                                                             (line   65)
* http_open() (urllib.request.HTTPHandler method): HTTPHandler Objects.
                                                             (line    6)
* HTTP_PORT (in module http.client):     http client — HTTP protocol client.
                                                             (line  200)
* http_response() (urllib.request.HTTPErrorProcessor method): HTTPErrorProcessor Objects.
                                                             (line    6)
* http_version (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  304)
* HTTP; http (standard module):          http — HTTP modules.
                                                             (line    8)
* HTTP; http.client (standard module):   http client — HTTP protocol client.
                                                             (line    8)
* HTTP; protocol:                        urllib request Restrictions.
                                                             (line    6)
* HTTP; protocol <1>:                    urllib request Restrictions.
                                                             (line   29)
* HTTP; protocol <2>:                    http — HTTP modules.
                                                             (line    8)
* HTTP; protocol <3>:                    http client — HTTP protocol client.
                                                             (line    8)
* HTTP; protocol <4>:                    http server — HTTP servers.
                                                             (line    8)
* http.server command line option; -b:   Command-line interface<5>.
                                                             (line   21)
* http.server command line option; -bind: Command-line interface<5>.
                                                             (line   21)
* http.server command line option; -cgi: Command-line interface<5>.
                                                             (line   54)
* http.server command line option; -d:   Command-line interface<5>.
                                                             (line   34)
* http.server command line option; -directory: Command-line interface<5>.
                                                             (line   34)
* http.server command line option; -p:   Command-line interface<5>.
                                                             (line   44)
* http.server command line option; -protocol: Command-line interface<5>.
                                                             (line   44)
* http.server command line option; port: Command-line interface<5>.
                                                             (line   14)
* http.server; security:                 Security considerations<3>.
                                                             (line    6)
* HTTPBasicAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  361)
* HTTPConnection (class in http.client): http client — HTTP protocol client.
                                                             (line   31)
* HTTPCookieProcessor (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  292)
* httpd:                                 http server — HTTP servers.
                                                             (line    8)
* HTTPDefaultErrorHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  283)
* HTTPDigestAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  385)
* HTTPError:                             urllib error — Exception classes raised by urllib request.
                                                             (line   29)
* HTTPErrorProcessor (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  445)
* HTTPException:                         http client — HTTP protocol client.
                                                             (line  131)
* HTTPHandler (class in logging.handlers): HTTPHandler.      (line   10)
* HTTPHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  409)
* HTTPMessage (class in http.client):    HTTPMessage Objects.
                                                             (line    6)
* HTTPMethod (class in http):            HTTP status category.
                                                             (line   38)
* httponly (http.cookies.Morsel attribute): Morsel Objects.  (line   13)
* HTTPPasswordMgr (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  318)
* HTTPPasswordMgrWithDefaultRealm (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  322)
* HTTPPasswordMgrWithPriorAuth (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  328)
* HTTPRedirectHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  288)
* HTTPResponse (class in http.client):   http client — HTTP protocol client.
                                                             (line   99)
* https_open() (urllib.request.HTTPSHandler method): HTTPSHandler Objects.
                                                             (line    6)
* HTTPS_PORT (in module http.client):    http client — HTTP protocol client.
                                                             (line  204)
* https_response() (urllib.request.HTTPErrorProcessor method): HTTPErrorProcessor Objects.
                                                             (line   18)
* HTTPSConnection (class in http.client): http client — HTTP protocol client.
                                                             (line   62)
* HTTPServer (class in http.server):     http server — HTTP servers.
                                                             (line   30)
* HTTPSHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  413)
* HTTPStatus (class in http):            http — HTTP modules.
                                                             (line   27)
* HV_GUID_BROADCAST (in module socket):  Constants<8>.       (line  344)
* HV_GUID_CHILDREN (in module socket):   Constants<8>.       (line  344)
* HV_GUID_LOOPBACK (in module socket):   Constants<8>.       (line  344)
* HV_GUID_PARENT (in module socket):     Constants<8>.       (line  344)
* HV_GUID_WILDCARD (in module socket):   Constants<8>.       (line  344)
* HV_GUID_ZERO (in module socket):       Constants<8>.       (line  344)
* HV_PROTOCOL_RAW (in module socket):    Constants<8>.       (line  344)
* HVSOCKET_ADDRESS_FLAG_PASSTHRU (in module socket): Constants<8>.
                                                             (line  344)
* HVSOCKET_CONNECT_TIMEOUT (in module socket): Constants<8>. (line  344)
* HVSOCKET_CONNECT_TIMEOUT_MAX (in module socket): Constants<8>.
                                                             (line  344)
* HVSOCKET_CONNECTED_SUSPEND (in module socket): Constants<8>.
                                                             (line  344)
* hypot() (in module math):              Summation and product functions.
                                                             (line   33)
* I (in module re):                      Flags.              (line   38)
* I/O control; buffering:                Built-in Functions. (line 1464)
* I/O control; buffering <1>:            Socket Objects.     (line  212)
* iadd() (in module operator):           In-place Operators. (line   36)
* iand() (in module operator):           In-place Operators. (line   41)
* iconcat() (in module operator):        In-place Operators. (line   46)
* id (ssl.SSLSession attribute):         SSL session.        (line   12)
* id() (unittest.TestCase method):       Test cases.         (line  747)
* idcok() (curses.window method):        Window Objects.     (line  290)
* ident (select.kevent attribute):       Kevent Objects.     (line    8)
* ident (threading.Thread attribute):    Thread objects.     (line  165)
* identchars (cmd.Cmd attribute):        Cmd Objects.        (line  134)
* identifier:                            Identifiers and keywords.
                                                             (line    6)
* identifier <1>:                        Identifiers Names.  (line    6)
* identify_column() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  143)
* identify_element() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  172)
* identify_region() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  150)
* identify_row() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  139)
* identify() (tkinter.ttk.Notebook method): ttk Notebook.    (line   32)
* identify() (tkinter.ttk.Treeview method): ttk Treeview.    (line  133)
* identify() (tkinter.ttk.Widget method): ttk Widget.        (line   11)
* identity of an object:                 Objects values and types.
                                                             (line   10)
* identity; test:                        Membership test operations.
                                                             (line   39)
* IDLE:                                  IDLE — Python editor and shell<2>.
                                                             (line    8)
* IDLE <1>:                              Glossary.           (line  782)
* idle command line option; -:           Command-line usage<3>.
                                                             (line   49)
* idle command line option; -c:          Command-line usage<3>.
                                                             (line   13)
* idle command line option; -d:          Command-line usage<3>.
                                                             (line   19)
* idle command line option; -e:          Command-line usage<3>.
                                                             (line   23)
* idle command line option; -h:          Command-line usage<3>.
                                                             (line   27)
* idle command line option; -i:          Command-line usage<3>.
                                                             (line   31)
* idle command line option; -r:          Command-line usage<3>.
                                                             (line   35)
* idle command line option; -s:          Command-line usage<3>.
                                                             (line   39)
* idle command line option; -t:          Command-line usage<3>.
                                                             (line   45)
* IDLE_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line   89)
* IDLESTARTUP:                           IDLE<41>.           (line  176)
* IDLESTARTUP <1>:                       IDLE<45>.           (line    9)
* IDLESTARTUP <2>:                       IDLE<51>.           (line    9)
* IDLESTARTUP <3>:                       Startup and Code Execution.
                                                             (line    7)
* IDLESTARTUP <4>:                       Command-line usage<3>.
                                                             (line   41)
* idlok() (curses.window method):        Window Objects.     (line  298)
* If (class in ast):                     Control flow.       (line    9)
* if_indextoname() (in module socket):   Other functions<2>. (line  441)
* if_nameindex() (in module socket):     Other functions<2>. (line  398)
* if_nametoindex() (in module socket):   Other functions<2>. (line  423)
* if; conditional expression:            Conditional expressions.
                                                             (line    6)
* if; in comprehensions:                 Displays for lists sets and dictionaries.
                                                             (line   14)
* IfExp (class in ast):                  Expressions<2>.     (line  157)
* ifloordiv() (in module operator):      In-place Operators. (line   52)
* iglob() (in module glob):              glob — Unix style pathname pattern expansion.
                                                             (line   79)
* ignorableWhitespace() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  147)
* ignore (bdb.Breakpoint attribute):     bdb — Debugger framework.
                                                             (line  116)
* IGNORE (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  151)
* ignore (pdb command):                  Debugger commands.  (line  144)
* ignore_environment (sys.flags attribute): sys — System-specific parameters and functions.
                                                             (line  551)
* ignore_errors() (in module codecs):    Error Handlers.     (line  147)
* IGNORE_EXCEPTION_DETAIL (in module doctest): Option Flags. (line   56)
* ignore_patterns() (in module shutil):  Directory and files operations.
                                                             (line  191)
* ignore_warnings() (in module test.support.warnings_helper): test support warnings_helper — Utilities for warnings tests.
                                                             (line   11)
* ignore; error handler's name:          Error Handlers.     (line   15)
* IGNORECASE (in module re):             Flags.              (line   38)
* IISCGIHandler (class in wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line   24)
* IllegalMonthError:                     calendar — General calendar-related functions.
                                                             (line  516)
* IllegalWeekdayError:                   calendar — General calendar-related functions.
                                                             (line  525)
* ilshift() (in module operator):        In-place Operators. (line   57)
* imag (numbers.Complex attribute):      The numeric tower.  (line   19)
* imag (sys.hash_info attribute):        sys — System-specific parameters and functions.
                                                             (line 1049)
* imaginary literal:                     Numeric literals.   (line    6)
* imap_unordered() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line  147)
* imap() (multiprocessing.pool.Pool method): Process Pools.  (line  132)
* IMAP4 (class in imaplib):              imaplib — IMAP4 protocol client.
                                                             (line   25)
* IMAP4_SSL (class in imaplib):          imaplib — IMAP4 protocol client.
                                                             (line   74)
* IMAP4_SSL; protocol:                   imaplib — IMAP4 protocol client.
                                                             (line    8)
* IMAP4_stream (class in imaplib):       imaplib — IMAP4 protocol client.
                                                             (line  104)
* IMAP4_stream; protocol:                imaplib — IMAP4 protocol client.
                                                             (line    8)
* IMAP4; protocol:                       imaplib — IMAP4 protocol client.
                                                             (line    8)
* IMAP4.abort:                           imaplib — IMAP4 protocol client.
                                                             (line   58)
* IMAP4.error:                           imaplib — IMAP4 protocol client.
                                                             (line   53)
* IMAP4.readonly:                        imaplib — IMAP4 protocol client.
                                                             (line   65)
* imatmul() (in module operator):        In-place Operators. (line   72)
* immedok() (curses.window method):      Window Objects.     (line  304)
* immortal:                              Glossary.           (line  789)
* immutable:                             Glossary.           (line  799)
* immutable object:                      Objects values and types.
                                                             (line   10)
* immutable; data; type:                 Literals<2>.        (line   17)
* immutable; object:                     Literals<2>.        (line   17)
* immutable; object <1>:                 Dictionary displays.
                                                             (line   37)
* immutable; sequence; types:            Immutable Sequence Types.
                                                             (line    6)
* imod() (in module operator):           In-place Operators. (line   62)
* impl_detail() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  536)
* implementation (in module sys):        sys — System-specific parameters and functions.
                                                             (line 1099)
* Import (class in ast):                 Imports.            (line    6)
* import hooks:                          Import hooks.       (line    6)
* import machinery:                      The import system.  (line    6)
* import path:                           Glossary.           (line  810)
* import_curses (C macro):               Curses C API.       (line   15)
* import_fresh_module() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   16)
* IMPORT_FROM (opcode):                  Python Bytecode Instructions.
                                                             (line  827)
* import_module() (in module importlib): Functions<12>.      (line   14)
* import_module() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   52)
* IMPORT_NAME (opcode):                  Python Bytecode Instructions.
                                                             (line  818)
* importer:                              Glossary.           (line  823)
* ImportError:                           Concrete exceptions.
                                                             (line   52)
* ImportFrom (class in ast):             Imports.            (line   20)
* importing:                             Glossary.           (line  818)
* ImportWarning:                         Warnings.           (line   61)
* ImproperConnectionState:               http client — HTTP protocol client.
                                                             (line  161)
* imul() (in module operator):           In-place Operators. (line   67)
* In (class in ast):                     Expressions<2>.     (line  108)
* in_dll() (ctypes._CData method):       Data types<2>.      (line   63)
* in_table_a1() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line   39)
* in_table_b1() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line   44)
* in_table_c11_c12() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   68)
* in_table_c11() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   59)
* in_table_c12() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   63)
* in_table_c21_c22() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   83)
* in_table_c21() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   73)
* in_table_c22() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   78)
* in_table_c3() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line   88)
* in_table_c4() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line   92)
* in_table_c5() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line   97)
* in_table_c6() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  101)
* in_table_c7() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  106)
* in_table_c8() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  111)
* in_table_c9() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  116)
* in_table_d1() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  120)
* in_table_d2() (in module stringprep):  stringprep — Internet String Preparation.
                                                             (line  125)
* in_transaction (sqlite3.Connection attribute): Connection objects.
                                                             (line  765)
* inch() (curses.window method):         Window Objects.     (line  312)
* include() (in module xml.etree.ElementInclude): Functions<10>.
                                                             (line   17)
* inclusive (tracemalloc.DomainFilter attribute): DomainFilter.
                                                             (line   12)
* inclusive (tracemalloc.Filter attribute): Filter.          (line   39)
* inclusive; or:                         Binary bitwise operations.
                                                             (line   20)
* Incomplete:                            binascii — Convert between binary and ASCII.
                                                             (line  161)
* IncompleteRead:                        http client — HTTP protocol client.
                                                             (line  157)
* IncompleteReadError:                   Exceptions<13>.     (line   43)
* incr_item():                           Exceptions<21>.     (line   78)
* incr_item() <1>:                       Exceptions<21>.     (line  123)
* increment_lineno() (in module ast):    ast Helpers.        (line  155)
* IncrementalDecoder (class in codecs):  IncrementalDecoder Objects.
                                                             (line   11)
* incrementaldecoder (codecs.CodecInfo attribute): codecs — Codec registry and base classes.
                                                             (line   87)
* IncrementalEncoder (class in codecs):  IncrementalEncoder Objects.
                                                             (line   11)
* incrementalencoder (codecs.CodecInfo attribute): codecs — Codec registry and base classes.
                                                             (line   87)
* IncrementalNewlineDecoder (class in io): Text I/O<2>.      (line  286)
* IncrementalParser (class in xml.sax.xmlreader): xml sax xmlreader — Interface for XML parsers.
                                                             (line   20)
* indent (doctest.Example attribute):    Example Objects.    (line   46)
* INDENT (in module token):              token — Constants used with Python parse trees.
                                                             (line   86)
* indent (reprlib.Repr attribute):       Repr Objects.       (line   54)
* INDENT token:                          Indentation.        (line   33)
* indent() (in module textwrap):         textwrap — Text wrapping and filling.
                                                             (line  102)
* indent() (in module xml.etree.ElementTree): Functions<9>.  (line  118)
* indentation:                           Indentation.        (line    6)
* IndentationError:                      Concrete exceptions.
                                                             (line  356)
* index (inspect.FrameInfo attribute):   The interpreter stack.
                                                             (line   37)
* index (inspect.Traceback attribute):   The interpreter stack.
                                                             (line   77)
* index operation:                       Sequences.          (line    6)
* index() (array.array method):          array — Efficient arrays of numeric values.
                                                             (line  199)
* index() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  154)
* index() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  154)
* index() (collections.abc.ByteString method): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   82)
* index() (collections.deque method):    deque objects.      (line   70)
* index() (in module operator):          operator — Standard operators as functions.
                                                             (line   93)
* index() (multiprocessing.shared_memory.ShareableList method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  336)
* index() (sequence method):             Common Sequence Operations.
                                                             (line  176)
* index() (str method):                  String Methods<2>.  (line  233)
* index() (tkinter.ttk.Notebook method): ttk Notebook.       (line   37)
* index() (tkinter.ttk.Treeview method): ttk Treeview.       (line  178)
* IndexError:                            Concrete exceptions.
                                                             (line   80)
* indexOf() (in module operator):        operator — Standard operators as functions.
                                                             (line  201)
* IndexSizeErr:                          Exceptions<20>.     (line   34)
* indices() (slice method):              Slice objects.      (line   16)
* INDIRECT (inspect.BufferFlags attribute): Buffer flags.    (line   31)
* inet_aton() (in module socket):        Other functions<2>. (line  258)
* inet_ntoa() (in module socket):        Other functions<2>. (line  277)
* inet_ntop() (in module socket):        Other functions<2>. (line  312)
* inet_pton() (in module socket):        Other functions<2>. (line  294)
* Inexact (class in decimal):            Signals.            (line   43)
* inf (in module cmath):                 Constants<3>.       (line   20)
* inf (in module math):                  Constants<2>.       (line   24)
* inf (sys.hash_info attribute):         sys — System-specific parameters and functions.
                                                             (line 1041)
* infile (shlex.shlex attribute):        shlex Objects.      (line  140)
* Infinity:                              Built-in Functions. (line  724)
* infj (in module cmath):                Constants<3>.       (line   26)
* INFO (in module logging):              Logging Levels.     (line   29)
* INFO (in module tkinter.messagebox):   tkinter messagebox — Tkinter message prompts.
                                                             (line  194)
* info() (dis.Bytecode method):          Bytecode analysis.  (line   63)
* info() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   63)
* info() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   84)
* info() (in module logging):            Module-Level Functions.
                                                             (line   64)
* info() (logging.Logger method):        Logger Objects.     (line  288)
* info() (urllib.response.addinfourl method): urllib response — Response classes used by urllib.
                                                             (line   35)
* infolist() (zipfile.ZipFile method):   ZipFile objects.    (line  118)
* inheritance:                           Class definitions.  (line    6)
* ini file:                              configparser — Configuration file parser.
                                                             (line    8)
* init_color() (in module curses):       Functions<6>.       (line  220)
* init_pair() (in module curses):        Functions<6>.       (line  231)
* init() (in module mimetypes):          mimetypes — Map filenames to MIME types.
                                                             (line   91)
* inited (in module mimetypes):          mimetypes — Map filenames to MIME types.
                                                             (line  130)
* initgroups() (in module os):           Process Parameters. (line  336)
* initial_indent (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  209)
* initproc (C type):                     Slot Type typedefs. (line   35)
* initscr() (in module curses):          Functions<6>.       (line  244)
* InitVar (class in dataclasses):        Module contents<5>. (line  328)
* inode() (os.DirEntry method):          Files and Directories.
                                                             (line  962)
* input:                                 Expression input.   (line    6)
* input_charset (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   53)
* input_codec (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   82)
* input() (in module fileinput):         fileinput — Iterate over lines from multiple input streams.
                                                             (line   56)
* InputSource (class in xml.sax.xmlreader): xml sax xmlreader — Interface for XML parsers.
                                                             (line   51)
* InputStream (class in wsgiref.types):  wsgiref types – WSGI types for static type checking.
                                                             (line   24)
* inquiry (C type):                      Supporting Cyclic Garbage Collection.
                                                             (line  202)
* insch() (curses.window method):        Window Objects.     (line  318)
* insdelln() (curses.window method):     Window Objects.     (line  325)
* insert_text() (in module readline):    Line buffer.        (line   13)
* insert() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  210)
* insert() (collections.deque method):   deque objects.      (line   78)
* insert() (sequence method):            Mutable Sequence Types.
                                                             (line   98)
* insert() (tkinter.ttk.Notebook method): ttk Notebook.      (line   42)
* insert() (tkinter.ttk.Treeview method): ttk Treeview.      (line  183)
* insert() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  129)
* insertBefore() (xml.dom.Node method):  Node Objects.       (line  121)
* insertln() (curses.window method):     Window Objects.     (line  333)
* insnstr() (curses.window method):      Window Objects.     (line  338)
* insort_left() (in module bisect):      bisect — Array bisection algorithm.
                                                             (line   71)
* insort_right() (in module bisect):     bisect — Array bisection algorithm.
                                                             (line   89)
* insort() (in module bisect):           bisect — Array bisection algorithm.
                                                             (line   89)
* inspect (sys.flags attribute):         sys — System-specific parameters and functions.
                                                             (line  530)
* inspect command line option; -details: Command-line interface<8>.
                                                             (line   13)
* InspectLoader (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  199)
* insstr() (curses.window method):       Window Objects.     (line  349)
* install_opener() (in module urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  112)
* install_scripts() (venv.EnvBuilder method): API<2>.        (line  183)
* install() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   72)
* install() (in module gettext):         Class-based API.    (line   68)
* installHandler() (in module unittest): Signal Handling.    (line   29)
* instance; call:                        Calls.              (line  157)
* instate() (tkinter.ttk.Widget method): ttk Widget.         (line   18)
* instr() (curses.window method):        Window Objects.     (line  359)
* instream (shlex.shlex attribute):      shlex Objects.      (line  146)
* Instruction (class in dis):            Python Bytecode Instructions.
                                                             (line   10)
* INSTRUCTION (monitoring event):        Events.             (line   30)
* Instruction.arg (in module dis):       Python Bytecode Instructions.
                                                             (line   34)
* Instruction.argrepr (in module dis):   Python Bytecode Instructions.
                                                             (line   46)
* Instruction.argval (in module dis):    Python Bytecode Instructions.
                                                             (line   42)
* Instruction.baseopcode (in module dis): Python Bytecode Instructions.
                                                             (line   24)
* Instruction.baseopname (in module dis): Python Bytecode Instructions.
                                                             (line   29)
* Instruction.cache_info (in module dis): Python Bytecode Instructions.
                                                             (line   92)
* Instruction.cache_offset (in module dis): Python Bytecode Instructions.
                                                             (line   61)
* Instruction.end_offset (in module dis): Python Bytecode Instructions.
                                                             (line   65)
* Instruction.is_jump_target (in module dis): Python Bytecode Instructions.
                                                             (line   78)
* Instruction.jump_target (in module dis): Python Bytecode Instructions.
                                                             (line   82)
* Instruction.line_number (in module dis): Python Bytecode Instructions.
                                                             (line   73)
* Instruction.offset (in module dis):    Python Bytecode Instructions.
                                                             (line   51)
* Instruction.oparg (in module dis):     Python Bytecode Instructions.
                                                             (line   38)
* Instruction.opcode (in module dis):    Python Bytecode Instructions.
                                                             (line   14)
* Instruction.opname (in module dis):    Python Bytecode Instructions.
                                                             (line   20)
* Instruction.positions (in module dis): Python Bytecode Instructions.
                                                             (line   87)
* Instruction.start_offset (in module dis): Python Bytecode Instructions.
                                                             (line   55)
* Instruction.starts_line (in module dis): Python Bytecode Instructions.
                                                             (line   69)
* int (built-in class):                  Built-in Functions. (line  953)
* int (uuid.UUID attribute):             uuid — UUID objects according to RFC 4122.
                                                             (line  132)
* int_info (in module sys):              sys — System-specific parameters and functions.
                                                             (line 1142)
* int_max_str_digits (sys.flags attribute): sys — System-specific parameters and functions.
                                                             (line  576)
* Int2AP() (in module imaplib):          imaplib — IMAP4 protocol client.
                                                             (line  118)
* integer:                               Immutable sequences.
                                                             (line   15)
* integer literal:                       Numeric literals.   (line    6)
* integer; literals:                     Numeric Types — int float complex.
                                                             (line   19)
* integer; representation:               numbers Integral.   (line    9)
* Integral (class in numbers):           The numeric tower.  (line   59)
* Integrated Development Environment:    IDLE — Python editor and shell<2>.
                                                             (line    8)
* IntegrityError:                        Exceptions<7>.      (line   65)
* IntEnum (class in enum):               Data types.         (line  407)
* interact (pdb command):                Debugger commands.  (line  351)
* interact() (code.InteractiveConsole method): Interactive Console Objects.
                                                             (line   10)
* interact() (in module code):           code — Interpreter base classes.
                                                             (line   42)
* interactive:                           Glossary.           (line  828)
* Interactive (class in ast):            Root nodes.         (line   37)
* interactive (sys.flags attribute):     sys — System-specific parameters and functions.
                                                             (line  533)
* interactive mode:                      Complete Python programs.
                                                             (line   19)
* InteractiveConsole (class in code):    code — Interpreter base classes.
                                                             (line   30)
* InteractiveInterpreter (class in code): code — Interpreter base classes.
                                                             (line   15)
* InterfaceError:                        Exceptions<7>.      (line   37)
* intern() (in module sys):              sys — System-specific parameters and functions.
                                                             (line 1187)
* internal type:                         Internal types.     (line    6)
* internal_attr (zipfile.ZipInfo attribute): ZipInfo objects.
                                                             (line  138)
* Internaldate2tuple() (in module imaplib): imaplib — IMAP4 protocol client.
                                                             (line  112)
* InternalError:                         Exceptions<7>.      (line   71)
* internalSubset (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   27)
* Internet:                              Internet Protocols and Support.
                                                             (line    6)
* INTERNET_TIMEOUT (in module test.support): test support — Utilities for the Python test suite.
                                                             (line   65)
* interpolated string literal:           Fancier Output Formatting.
                                                             (line   93)
* interpolated string literal <1>:       String literal concatenation.
                                                             (line   24)
* interpolated string literal <2>:       String Methods<2>.  (line  966)
* interpolation, string (%):             printf-style String Formatting.
                                                             (line    6)
* interpolation; bytearray (%):          printf-style Bytes Formatting.
                                                             (line    6)
* interpolation; bytes (%):              printf-style Bytes Formatting.
                                                             (line    6)
* InterpolationDepthError:               Exceptions<8>.      (line   42)
* InterpolationError:                    Exceptions<8>.      (line   37)
* InterpolationMissingOptionError:       Exceptions<8>.      (line   49)
* InterpolationSyntaxError:              Exceptions<8>.      (line   54)
* interpreted:                           Glossary.           (line  838)
* interpreter:                           Top-level components.
                                                             (line    6)
* interpreter lock:                      Thread State and the Global Interpreter Lock.
                                                             (line    6)
* interpreter prompts:                   sys — System-specific parameters and functions.
                                                             (line 1485)
* interpreter shutdown:                  Glossary.           (line  848)
* interpreter_requires_environment() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line    9)
* interrupt_main() (in module _thread):  _thread — Low-level threading API.
                                                             (line   56)
* interrupt() (sqlite3.Connection method): Connection objects.
                                                             (line  339)
* InterruptedError:                      OS exceptions.      (line   73)
* intersection_update() (set method):    Set Types — set frozenset.
                                                             (line  178)
* intersection() (frozenset method):     Set Types — set frozenset.
                                                             (line  105)
* intersection() (set method):           Set Types — set frozenset.
                                                             (line  105)
* IntFlag (class in enum):               Data types.         (line  587)
* intro (cmd.Cmd attribute):             Cmd Objects.        (line  149)
* InuseAttributeErr:                     Exceptions<20>.     (line   39)
* inv_cdf() (statistics.NormalDist method): NormalDist objects.
                                                             (line   92)
* inv() (in module operator):            operator — Standard operators as functions.
                                                             (line  102)
* InvalidAccessErr:                      Exceptions<20>.     (line   44)
* invalidate_caches() (importlib.abc.MetaPathFinder method): importlib abc – Abstract base classes related to import.
                                                             (line   48)
* invalidate_caches() (importlib.abc.PathEntryFinder method): importlib abc – Abstract base classes related to import.
                                                             (line   83)
* invalidate_caches() (importlib.machinery.FileFinder method): importlib machinery – Importers and path hooks.
                                                             (line  190)
* invalidate_caches() (importlib.machinery.PathFinder class method): importlib machinery – Importers and path hooks.
                                                             (line  139)
* invalidate_caches() (in module importlib): Functions<12>.  (line   38)
* invalidate_caches() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   89)
* InvalidBase64CharactersDefect:         email errors Exception and Defect classes.
                                                             (line  129)
* InvalidBase64LengthDefect:             email errors Exception and Defect classes.
                                                             (line  135)
* InvalidBase64PaddingDefect:            email errors Exception and Defect classes.
                                                             (line  123)
* InvalidCharacterErr:                   Exceptions<20>.     (line   49)
* InvalidDateDefect:                     email errors Exception and Defect classes.
                                                             (line  141)
* InvalidFileException:                  plistlib — Generate and parse Apple plist files.
                                                             (line  170)
* InvalidModificationErr:                Exceptions<20>.     (line   57)
* InvalidOperation (class in decimal):   Signals.            (line   51)
* InvalidStateErr:                       Exceptions<20>.     (line   61)
* InvalidStateError:                     Exception classes.  (line   26)
* InvalidStateError <1>:                 Exceptions<13>.     (line   29)
* InvalidTZPathWarning:                  Exceptions and warnings.
                                                             (line   12)
* InvalidURL:                            http client — HTTP protocol client.
                                                             (line  140)
* inversion:                             Unary arithmetic and bitwise operations.
                                                             (line   18)
* Invert (class in ast):                 Expressions<2>.     (line   27)
* invert() (in module operator):         operator — Standard operators as functions.
                                                             (line  102)
* invocation:                            Callable types.     (line    6)
* IO (class in typing):                  ABCs for working with IO.
                                                             (line    6)
* IO_REPARSE_TAG_APPEXECLINK (in module stat): stat — Interpreting stat results.
                                                             (line  476)
* IO_REPARSE_TAG_MOUNT_POINT (in module stat): stat — Interpreting stat results.
                                                             (line  476)
* IO_REPARSE_TAG_SYMLINK (in module stat): stat — Interpreting stat results.
                                                             (line  476)
* IOBase (class in io):                  I/O Base Classes.   (line    6)
* IOCTL_VM_SOCKETS_GET_LOCAL_CID (in module socket): Constants<8>.
                                                             (line  274)
* ioctl() (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  103)
* ioctl() (socket.socket method):        Socket Objects.     (line  179)
* IOError:                               Concrete exceptions.
                                                             (line  497)
* ior() (in module operator):            In-place Operators. (line   79)
* ios_ver() (in module platform):        iOS platform.       (line    6)
* ip (ipaddress.IPv4Interface attribute): Interface objects. (line   19)
* ip (ipaddress.IPv6Interface attribute): Interface objects. (line   74)
* ip_address() (in module ipaddress):    Convenience factory functions.
                                                             (line    9)
* ip_interface() (in module ipaddress):  Convenience factory functions.
                                                             (line   37)
* ip_network() (in module ipaddress):    Convenience factory functions.
                                                             (line   23)
* ipow() (in module operator):           In-place Operators. (line   84)
* ipv4_mapped (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  299)
* IPv4Address (class in ipaddress):      Address objects.    (line   13)
* IPv4Interface (class in ipaddress):    Interface objects.  (line    9)
* IPv4Network (class in ipaddress):      Network objects.    (line   13)
* IPV6_ENABLED (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   11)
* ipv6_mapped (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  188)
* IPv6Address (class in ipaddress):      Address objects.    (line  220)
* IPv6Interface (class in ipaddress):    Interface objects.  (line   64)
* IPv6Network (class in ipaddress):      Network objects.    (line  253)
* irrefutable case block:                Irrefutable Case Blocks.
                                                             (line    6)
* irshift() (in module operator):        In-place Operators. (line   89)
* Is (class in ast):                     Expressions<2>.     (line  108)
* is_() (in module operator):            operator — Standard operators as functions.
                                                             (line   63)
* is_absolute() (pathlib.PurePath method): Methods and properties.
                                                             (line  183)
* is_active() (asyncio.AbstractChildWatcher method): Process Watchers.
                                                             (line   72)
* is_active() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line  110)
* is_alive() (multiprocessing.Process method): Process and exceptions.
                                                             (line  126)
* is_alive() (threading.Thread method):  Thread objects.     (line  191)
* is_android (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line   40)
* is_annotated() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  230)
* is_assigned() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  241)
* is_async (pyclbr.Function attribute):  Function Objects.   (line   41)
* is_attachment() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  445)
* is_authenticated() (urllib.request.HTTPPasswordMgrWithPriorAuth method): HTTPPasswordMgrWithPriorAuth Objects.
                                                             (line   30)
* is_block_device() (pathlib.Path method): Querying file type and status.
                                                             (line  127)
* is_blocked() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   60)
* is_canonical() (decimal.Context method): Context objects.  (line  323)
* is_canonical() (decimal.Decimal method): Decimal objects.  (line  276)
* is_char_device() (pathlib.Path method): Querying file type and status.
                                                             (line  136)
* IS_CHARACTER_JUNK() (in module difflib): difflib — Helpers for computing deltas.
                                                             (line  361)
* is_check_supported() (in module lzma): Miscellaneous<2>.   (line    6)
* is_closed() (asyncio.loop method):     Running and stopping the loop.
                                                             (line   39)
* is_closing() (asyncio.BaseTransport method): Base Transport.
                                                             (line   17)
* is_closing() (asyncio.StreamWriter method): StreamWriter.  (line  110)
* is_dataclass() (in module dataclasses): Module contents<5>.
                                                             (line  470)
* is_declared_global() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  221)
* is_dir() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  528)
* is_dir() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  106)
* is_dir() (os.DirEntry method):         Files and Directories.
                                                             (line  973)
* is_dir() (pathlib.Path method):        Querying file type and status.
                                                             (line   67)
* is_dir() (zipfile.Path method):        Path objects.       (line   57)
* is_dir() (zipfile.ZipInfo method):     ZipInfo objects.    (line   43)
* is_enabled() (in module faulthandler): Fault handler state.
                                                             (line   31)
* is_expired() (http.cookiejar.Cookie method): Cookie Objects<2>.
                                                             (line  111)
* is_fifo() (pathlib.Path method):       Querying file type and status.
                                                             (line  119)
* is_file() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  532)
* is_file() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  110)
* is_file() (os.DirEntry method):        Files and Directories.
                                                             (line 1002)
* is_file() (pathlib.Path method):       Querying file type and status.
                                                             (line   54)
* is_file() (zipfile.Path method):       Path objects.       (line   61)
* is_finalized() (in module gc):         gc — Garbage Collector interface.
                                                             (line  184)
* is_finalizing() (in module sys):       sys — System-specific parameters and functions.
                                                             (line 1213)
* is_finite() (decimal.Context method):  Context objects.    (line  327)
* is_finite() (decimal.Decimal method):  Decimal objects.    (line  282)
* is_free() (symtable.Symbol method):    Examining Symbol Tables.
                                                             (line  236)
* is_global (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  135)
* is_global (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  279)
* is_global() (symtable.Symbol method):  Examining Symbol Tables.
                                                             (line  213)
* is_hop_by_hop() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line  112)
* is_imported() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  204)
* is_infinite() (decimal.Context method): Context objects.   (line  331)
* is_infinite() (decimal.Decimal method): Decimal objects.   (line  287)
* is_integer() (float method):           Additional Methods on Float.
                                                             (line   16)
* is_integer() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  128)
* is_integer() (int method):             Additional Methods on Integer Types.
                                                             (line  171)
* is_junction() (os.DirEntry method):    Files and Directories.
                                                             (line 1037)
* is_junction() (pathlib.Path method):   Querying file type and status.
                                                             (line   88)
* is_jython (in module test.support):    test support — Utilities for the Python test suite.
                                                             (line   36)
* IS_LINE_JUNK() (in module difflib):    difflib — Helpers for computing deltas.
                                                             (line  354)
* is_linetouched() (curses.window method): Window Objects.   (line  369)
* is_link_local (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  183)
* is_link_local (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   80)
* is_link_local (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  289)
* is_link_local (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  307)
* is_local() (symtable.Symbol method):   Examining Symbol Tables.
                                                             (line  226)
* is_loopback (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  178)
* is_loopback (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   78)
* is_loopback (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  287)
* is_loopback (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  305)
* is_mount() (pathlib.Path method):      Querying file type and status.
                                                             (line   95)
* is_multicast (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   92)
* is_multicast (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   70)
* is_multicast (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  275)
* is_multicast (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  297)
* is_multipart() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  134)
* is_multipart() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  145)
* is_namespace() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  245)
* is_nan() (decimal.Context method):     Context objects.    (line  335)
* is_nan() (decimal.Decimal method):     Decimal objects.    (line  292)
* is_nested() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   94)
* is_nonlocal() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  217)
* is_normal() (decimal.Context method):  Context objects.    (line  340)
* is_normal() (decimal.Decimal method):  Decimal objects.    (line  297)
* is_normalized() (in module unicodedata): unicodedata — Unicode Database.
                                                             (line  169)
* is_not_allowed() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   74)
* is_not() (in module operator):         operator — Standard operators as functions.
                                                             (line   67)
* IS_OP (opcode):                        Python Bytecode Instructions.
                                                             (line  806)
* is_optimized() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line   90)
* is_package() (importlib.abc.InspectLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  231)
* is_package() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  422)
* is_package() (importlib.machinery.ExtensionFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  328)
* is_package() (importlib.machinery.SourceFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  220)
* is_package() (importlib.machinery.SourcelessFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  264)
* is_package() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   73)
* is_parameter() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  209)
* is_private (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   97)
* is_private (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   72)
* is_private (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  277)
* is_private (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  299)
* is_protocol() (in module typing):      Introspection helpers.
                                                             (line  115)
* is_python_build() (in module sysconfig): Other functions<3>.
                                                             (line   46)
* is_qnan() (decimal.Context method):    Context objects.    (line  345)
* is_qnan() (decimal.Decimal method):    Decimal objects.    (line  303)
* is_reading() (asyncio.ReadTransport method): Read-only Transports.
                                                             (line    6)
* is_referenced() (symtable.Symbol method): Examining Symbol Tables.
                                                             (line  200)
* is_relative_to() (pathlib.PurePath method): Methods and properties.
                                                             (line  202)
* is_reserved (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  163)
* is_reserved (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   76)
* is_reserved (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  285)
* is_reserved (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  303)
* is_reserved() (pathlib.PurePath method): Methods and properties.
                                                             (line  226)
* is_resource_enabled() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  244)
* is_resource() (importlib.abc.ResourceReader method): importlib abc – Abstract base classes related to import.
                                                             (line  482)
* is_resource() (importlib.resources.abc.ResourceReader method): importlib resources abc – Abstract base classes for resources.
                                                             (line   62)
* is_resource() (in module importlib.resources): Functional API.
                                                             (line  136)
* is_running() (asyncio.loop method):    Running and stopping the loop.
                                                             (line   35)
* is_safe (uuid.UUID attribute):         uuid — UUID objects according to RFC 4122.
                                                             (line  152)
* is_serving() (asyncio.Server method):  Server objects.     (line  117)
* is_set() (asyncio.Event method):       Event.              (line   65)
* is_set() (threading.Event method):     Event objects.      (line   24)
* is_signed() (decimal.Context method):  Context objects.    (line  350)
* is_signed() (decimal.Decimal method):  Decimal objects.    (line  308)
* is_site_local (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  291)
* is_site_local (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  357)
* is_skipped_module() (bdb.Bdb method):  bdb — Debugger framework.
                                                             (line  239)
* is_snan() (decimal.Context method):    Context objects.    (line  354)
* is_snan() (decimal.Decimal method):    Decimal objects.    (line  314)
* is_socket() (pathlib.Path method):     Querying file type and status.
                                                             (line  110)
* is_stack_trampoline_active() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1774)
* is_subnormal() (decimal.Context method): Context objects.  (line  359)
* is_subnormal() (decimal.Decimal method): Decimal objects.  (line  319)
* is_symlink() (os.DirEntry method):     Files and Directories.
                                                             (line 1018)
* is_symlink() (pathlib.Path method):    Querying file type and status.
                                                             (line   80)
* is_symlink() (zipfile.Path method):    Path objects.       (line   65)
* is_tarfile() (in module tarfile):      tarfile — Read and write tar archive files.
                                                             (line  189)
* is_term_resized() (in module curses):  Functions<6>.       (line  252)
* is_tracing() (in module tracemalloc):  Functions<11>.      (line   60)
* is_tracked() (in module gc):           gc — Garbage Collector interface.
                                                             (line  159)
* is_typeddict() (in module typing):     Introspection helpers.
                                                             (line  130)
* is_unspecified (ipaddress.IPv4Address attribute): Address objects.
                                                             (line  158)
* is_unspecified (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   74)
* is_unspecified (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  283)
* is_unspecified (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  301)
* is_valid() (string.Template method):   Template strings.   (line   67)
* is_wintouched() (curses.window method): Window Objects.    (line  376)
* is_zero() (decimal.Context method):    Context objects.    (line  363)
* is_zero() (decimal.Decimal method):    Decimal objects.    (line  324)
* is_zipfile() (in module zipfile):      zipfile — Work with ZIP archives.
                                                             (line   76)
* isabs() (in module os.path):           os path — Common pathname manipulations.
                                                             (line  208)
* isabstract() (in module inspect):      Types and members.  (line  528)
* IsADirectoryError:                     OS exceptions.      (line   83)
* isalnum() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  507)
* isalnum() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  507)
* isalnum() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  133)
* isalnum() (str method):                String Methods<2>.  (line  249)
* isalpha() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  525)
* isalpha() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  525)
* isalpha() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  138)
* isalpha() (str method):                String Methods<2>.  (line  266)
* isascii() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  540)
* isascii() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  540)
* isascii() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  143)
* isascii() (str method):                String Methods<2>.  (line  286)
* isasyncgen() (in module inspect):      Types and members.  (line  488)
* isasyncgenfunction() (in module inspect): Types and members.
                                                             (line  467)
* isatty() (in module os):               File Descriptor Operations.
                                                             (line  260)
* isatty() (io.IOBase method):           I/O Base Classes.   (line   72)
* isawaitable() (in module inspect):     Types and members.  (line  446)
* isblank() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  147)
* isblk() (tarfile.TarInfo method):      TarInfo Objects.    (line  210)
* isbuiltin() (in module inspect):       Types and members.  (line  508)
* ischr() (tarfile.TarInfo method):      TarInfo Objects.    (line  206)
* isclass() (in module inspect):         Types and members.  (line  373)
* isclose() (in module cmath):           Classification functions.
                                                             (line   23)
* isclose() (in module math):            Floating point manipulation functions.
                                                             (line   25)
* iscntrl() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  151)
* iscode() (in module inspect):          Types and members.  (line  504)
* iscoroutine() (in module asyncio):     Introspection.      (line   26)
* iscoroutine() (in module inspect):     Types and members.  (line  439)
* iscoroutinefunction() (in module inspect): Types and members.
                                                             (line  403)
* isctrl() (in module curses.ascii):     curses ascii — Utilities for ASCII characters.
                                                             (line  192)
* isDaemon() (threading.Thread method):  Thread objects.     (line  213)
* isdatadescriptor() (in module inspect): Types and members. (line  555)
* isdecimal() (str method):              String Methods<2>.  (line  299)
* isdev() (tarfile.TarInfo method):      TarInfo Objects.    (line  218)
* isdevdrive() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  276)
* isdigit() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  548)
* isdigit() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  548)
* isdigit() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  156)
* isdigit() (str method):                String Methods<2>.  (line  315)
* isdir() (in module os.path):           os path — Common pathname manipulations.
                                                             (line  232)
* isdir() (tarfile.TarInfo method):      TarInfo Objects.    (line  194)
* isdisjoint() (frozenset method):       Set Types — set frozenset.
                                                             (line   67)
* isdisjoint() (set method):             Set Types — set frozenset.
                                                             (line   67)
* isdown() (in module turtle):           Drawing state.      (line   86)
* iselement() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  130)
* isenabled() (in module gc):            gc — Garbage Collector interface.
                                                             (line   30)
* isEnabledFor() (logging.Logger method): Logger Objects.    (line  144)
* isendwin() (in module curses):         Functions<6>.       (line  257)
* ISEOF() (in module token):             token — Constants used with Python parse trees.
                                                             (line   39)
* isfifo() (tarfile.TarInfo method):     TarInfo Objects.    (line  214)
* isfile() (in module os.path):          os path — Common pathname manipulations.
                                                             (line  224)
* isfile() (tarfile.TarInfo method):     TarInfo Objects.    (line  185)
* isfinite() (in module cmath):          Classification functions.
                                                             (line    6)
* isfinite() (in module math):           Floating point manipulation functions.
                                                             (line   60)
* isfirstline() (in module fileinput):   fileinput — Iterate over lines from multiple input streams.
                                                             (line  111)
* isframe() (in module inspect):         Types and members.  (line  500)
* isfunction() (in module inspect):      Types and members.  (line  382)
* isfuture() (in module asyncio):        Future Functions.   (line    6)
* isgenerator() (in module inspect):     Types and members.  (line  399)
* isgeneratorfunction() (in module inspect): Types and members.
                                                             (line  387)
* isgetsetdescriptor() (in module inspect): Types and members.
                                                             (line  568)
* isgraph() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  161)
* isidentifier() (str method):           String Methods<2>.  (line  325)
* isinf() (in module cmath):             Classification functions.
                                                             (line   13)
* isinf() (in module math):              Floating point manipulation functions.
                                                             (line   67)
* isjunction() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  240)
* iskeyword() (in module keyword):       keyword — Testing for Python keywords.
                                                             (line   13)
* isleap() (in module calendar):         calendar — General calendar-related functions.
                                                             (line  363)
* islice() (in module itertools):        Itertool Functions. (line  368)
* islink() (in module os.path):          os path — Common pathname manipulations.
                                                             (line  248)
* islnk() (tarfile.TarInfo method):      TarInfo Objects.    (line  202)
* islower() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  562)
* islower() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  562)
* islower() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  165)
* islower() (str method):                String Methods<2>.  (line  343)
* ismemberdescriptor() (in module inspect): Types and members.
                                                             (line  577)
* ismeta() (in module curses.ascii):     curses ascii — Utilities for ASCII characters.
                                                             (line  196)
* ismethod() (in module inspect):        Types and members.  (line  378)
* ismethoddescriptor() (in module inspect): Types and members.
                                                             (line  532)
* ismethodwrapper() (in module inspect): Types and members.  (line  513)
* ismodule() (in module inspect):        Types and members.  (line  369)
* ismount() (in module os.path):         os path — Common pathname manipulations.
                                                             (line  256)
* isnan() (in module cmath):             Classification functions.
                                                             (line   18)
* isnan() (in module math):              Floating point manipulation functions.
                                                             (line   72)
* ISNONTERMINAL() (in module token):     token — Constants used with Python parse trees.
                                                             (line   35)
* IsNot (class in ast):                  Expressions<2>.     (line  108)
* isnumeric() (str method):              String Methods<2>.  (line  349)
* isocalendar() (datetime.date method):  date Objects.       (line  244)
* isocalendar() (datetime.datetime method): datetime Objects.
                                                             (line  647)
* isoformat() (datetime.date method):    date Objects.       (line  271)
* isoformat() (datetime.datetime method): datetime Objects.  (line  652)
* isoformat() (datetime.time method):    time Objects.       (line  163)
* isolated (sys.flags attribute):        sys — System-specific parameters and functions.
                                                             (line  536)
* IsolatedAsyncioTestCase (class in unittest): Test cases.   (line  845)
* isolation_level (sqlite3.Connection attribute): Connection objects.
                                                             (line  775)
* isoweekday() (datetime.date method):   date Objects.       (line  237)
* isoweekday() (datetime.datetime method): datetime Objects. (line  641)
* isprint() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  169)
* isprintable() (str method):            String Methods<2>.  (line  371)
* ispunct() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  173)
* isqrt() (in module math):              Number-theoretic functions.
                                                             (line   43)
* isreadable() (in module pprint):       Functions<4>.       (line   84)
* isreadable() (pprint.PrettyPrinter method): PrettyPrinter Objects.
                                                             (line   66)
* isrecursive() (in module pprint):      Functions<4>.       (line   93)
* isrecursive() (pprint.PrettyPrinter method): PrettyPrinter Objects.
                                                             (line   74)
* isreg() (tarfile.TarInfo method):      TarInfo Objects.    (line  190)
* isreserved() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  295)
* isReservedKey() (http.cookies.Morsel method): Morsel Objects.
                                                             (line   65)
* isroutine() (in module inspect):       Types and members.  (line  523)
* isSameNode() (xml.dom.Node method):    Node Objects.       (line  102)
* issoftkeyword() (in module keyword):   keyword — Testing for Python keywords.
                                                             (line   24)
* isspace() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  579)
* isspace() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  579)
* isspace() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  178)
* isspace() (str method):                String Methods<2>.  (line  397)
* isstdin() (in module fileinput):       fileinput — Iterate over lines from multiple input streams.
                                                             (line  116)
* issubset() (frozenset method):         Set Types — set frozenset.
                                                             (line   74)
* issubset() (set method):               Set Types — set frozenset.
                                                             (line   74)
* issuperset() (frozenset method):       Set Types — set frozenset.
                                                             (line   86)
* issuperset() (set method):             Set Types — set frozenset.
                                                             (line   86)
* issym() (tarfile.TarInfo method):      TarInfo Objects.    (line  198)
* ISTERMINAL() (in module token):        token — Constants used with Python parse trees.
                                                             (line   31)
* istitle() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  587)
* istitle() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  587)
* istitle() (str method):                String Methods<2>.  (line  420)
* istraceback() (in module inspect):     Types and members.  (line  496)
* isub() (in module operator):           In-place Operators. (line   94)
* isupper() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  601)
* isupper() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  601)
* isupper() (in module curses.ascii):    curses ascii — Utilities for ASCII characters.
                                                             (line  183)
* isupper() (str method):                String Methods<2>.  (line  438)
* isvisible() (in module turtle):        Visibility.         (line   22)
* isxdigit() (in module curses.ascii):   curses ascii — Utilities for ASCII characters.
                                                             (line  187)
* ITALIC (in module tkinter.font):       tkinter font — Tkinter font wrapper.
                                                             (line   15)
* item selection:                        Sequences.          (line    6)
* item() (tkinter.ttk.Treeview method):  ttk Treeview.       (line  202)
* item() (xml.dom.NamedNodeMap method):  NamedNodeMap Objects.
                                                             (line   12)
* item() (xml.dom.NodeList method):      NodeList Objects.   (line   15)
* itemgetter() (in module operator):     operator — Standard operators as functions.
                                                             (line  271)
* items() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  270)
* items() (contextvars.Context method):  Manual Context Management.
                                                             (line  141)
* items() (dict method):                 Mapping Types — dict.
                                                             (line  186)
* items() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  240)
* items() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  349)
* items() (mailbox.Mailbox method):      Mailbox objects.    (line  141)
* items() (types.MappingProxyType method): Standard Interpreter Types.
                                                             (line  267)
* items() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   71)
* itemsize (array.array attribute):      array — Efficient arrays of numeric values.
                                                             (line  117)
* itemsize (memoryview attribute):       Memory Views.       (line  436)
* ItemsView (class in collections.abc):  Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  124)
* ItemsView (class in typing):           Aliases to container ABCs in collections abc.
                                                             (line   55)
* iter_attachments() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  560)
* iter_child_nodes() (in module ast):    ast Helpers.        (line  172)
* iter_fields() (in module ast):         ast Helpers.        (line  167)
* iter_importers() (in module pkgutil):  pkgutil — Package extension utility.
                                                             (line  106)
* iter_modules() (in module pkgutil):    pkgutil — Package extension utility.
                                                             (line  124)
* iter_parts() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  576)
* iter_unpack() (in module struct):      Functions and Exceptions.
                                                             (line   42)
* iter_unpack() (struct.Struct method):  Classes<3>.         (line   46)
* iter() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  135)
* iter() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   40)
* iterable:                              Glossary.           (line  863)
* Iterable (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   26)
* Iterable (class in typing):            Aliases to other ABCs in collections abc.
                                                             (line    6)
* iterable; unpacking:                   Expression lists.   (line   18)
* iterator:                              Glossary.           (line  884)
* Iterator (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   42)
* Iterator (class in typing):            Aliases to other ABCs in collections abc.
                                                             (line   14)
* iterator protocol:                     Iterator Types.     (line    6)
* iterdecode() (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  243)
* iterdir() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  524)
* iterdir() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  102)
* iterdir() (pathlib.Path method):       Reading directories.
                                                             (line    6)
* iterdir() (zipfile.Path method):       Path objects.       (line   53)
* iterdump() (sqlite3.Connection method): Connection objects.
                                                             (line  500)
* iterencode() (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  230)
* iterencode() (json.JSONEncoder method): Encoders and Decoders.
                                                             (line  229)
* iterfind() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  146)
* iterfind() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   47)
* iteritems() (mailbox.Mailbox method):  Mailbox objects.    (line  132)
* iterkeys() (mailbox.Mailbox method):   Mailbox objects.    (line  106)
* itermonthdates() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   66)
* itermonthdays() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   74)
* itermonthdays2() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   82)
* itermonthdays3() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   90)
* itermonthdays4() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  100)
* iternextfunc (C type):                 Slot Type typedefs. (line   92)
* iterparse() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  136)
* itertext() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  155)
* itervalues() (mailbox.Mailbox method): Mailbox objects.    (line  115)
* iterweekdays() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   60)
* ITIMER_PROF (in module signal):        Module contents<3>. (line  254)
* ITIMER_REAL (in module signal):        Module contents<3>. (line  244)
* ITIMER_VIRTUAL (in module signal):     Module contents<3>. (line  249)
* ItimerError:                           Module contents<3>. (line  287)
* itruediv() (in module operator):       In-place Operators. (line   99)
* ixor() (in module operator):           In-place Operators. (line  104)
* j; in numeric literal:                 Floating-point literals.
                                                             (line   28)
* JANUARY (in module calendar):          calendar — General calendar-related functions.
                                                             (line  488)
* java_ver() (in module platform):       Java platform.      (line    6)
* Java; language:                        numbers Real float. (line    6)
* join_thread() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   11)
* join_thread() (multiprocessing.Queue method): Pipes and Queues.
                                                             (line  188)
* join() (asyncio.Queue method):         Queue.              (line   53)
* join() (bytearray method):             Bytes and Bytearray Operations.
                                                             (line  166)
* join() (bytes method):                 Bytes and Bytearray Operations.
                                                             (line  166)
* join() (in module os.path):            os path — Common pathname manipulations.
                                                             (line  317)
* join() (in module shlex):              shlex — Simple lexical analysis.
                                                             (line   29)
* join() (multiprocessing.JoinableQueue method): Pipes and Queues.
                                                             (line  279)
* join() (multiprocessing.pool.Pool method): Process Pools.  (line  186)
* join() (multiprocessing.Process method): Process and exceptions.
                                                             (line   99)
* join() (queue.Queue method):           Queue Objects.      (line   88)
* join() (str method):                   String Methods<2>.  (line  453)
* join() (threading.Thread method):      Thread objects.     (line  126)
* JoinableQueue (class in multiprocessing): Pipes and Queues.
                                                             (line  255)
* JoinedStr (class in ast):              Literals<3>.        (line   42)
* joinpath() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  536)
* joinpath() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  114)
* joinpath() (pathlib.PurePath method):  Methods and properties.
                                                             (line  240)
* joinpath() (zipfile.Path method):      Path objects.       (line  114)
* js_output() (http.cookies.BaseCookie method): Cookie Objects.
                                                             (line   31)
* js_output() (http.cookies.Morsel method): Morsel Objects.  (line   76)
* json.tool command line option; -compact: Command line options.
                                                             (line   48)
* json.tool command line option; -h:     Command line options.
                                                             (line   54)
* json.tool command line option; -help:  Command line options.
                                                             (line   54)
* json.tool command line option; -indent: Command line options.
                                                             (line   48)
* json.tool command line option; -json-lines: Command line options.
                                                             (line   42)
* json.tool command line option; -no-ensure-ascii: Command line options.
                                                             (line   35)
* json.tool command line option; -no-indent: Command line options.
                                                             (line   48)
* json.tool command line option; -sort-keys: Command line options.
                                                             (line   29)
* json.tool command line option; -tab:   Command line options.
                                                             (line   48)
* json.tool command line option; infile: Command line options.
                                                             (line    6)
* json.tool command line option; outfile: Command line options.
                                                             (line   24)
* JSONDecodeError:                       Exceptions<17>.     (line    6)
* JSONDecoder (class in json):           Encoders and Decoders.
                                                             (line    6)
* JSONEncoder (class in json):           Encoders and Decoders.
                                                             (line  104)
* JULY (in module calendar):             calendar — General calendar-related functions.
                                                             (line  488)
* JUMP (monitoring event):               Events.             (line   34)
* JUMP (opcode):                         Python Bytecode Instructions.
                                                             (line 1427)
* jump (pdb command):                    Debugger commands.  (line  229)
* JUMP_BACKWARD (opcode):                Python Bytecode Instructions.
                                                             (line  837)
* JUMP_BACKWARD_NO_INTERRUPT (opcode):   Python Bytecode Instructions.
                                                             (line  843)
* JUMP_FORWARD (opcode):                 Python Bytecode Instructions.
                                                             (line  833)
* JUMP_NO_INTERRUPT (opcode):            Python Bytecode Instructions.
                                                             (line 1429)
* JUNE (in module calendar):             calendar — General calendar-related functions.
                                                             (line  488)
* kbhit() (in module msvcrt):            Console I/O.        (line    6)
* kde_random() (in module statistics):   Function details.   (line  185)
* kde() (in module statistics):          Function details.   (line  137)
* KEEP (enum.FlagBoundary attribute):    Data types.         (line  761)
* kevent() (in module select):           select — Waiting for I/O completion.
                                                             (line  108)
* key:                                   Dictionary displays.
                                                             (line    6)
* key (http.cookies.Morsel attribute):   Morsel Objects.     (line   57)
* key (zoneinfo.ZoneInfo attribute):     The ZoneInfo class. (line   78)
* key function:                          Glossary.           (line  912)
* KEY_A1 (in module curses):             Constants<6>.       (line  234)
* KEY_A3 (in module curses):             Constants<6>.       (line  237)
* KEY_ALL_ACCESS (in module winreg):     Access Rights.      (line    8)
* KEY_B2 (in module curses):             Constants<6>.       (line  240)
* KEY_BACKSPACE (in module curses):      Constants<6>.       (line  164)
* KEY_BEG (in module curses):            Constants<6>.       (line  252)
* KEY_BREAK (in module curses):          Constants<6>.       (line  146)
* KEY_BTAB (in module curses):           Constants<6>.       (line  249)
* KEY_C1 (in module curses):             Constants<6>.       (line  243)
* KEY_C3 (in module curses):             Constants<6>.       (line  246)
* KEY_CANCEL (in module curses):         Constants<6>.       (line  255)
* KEY_CATAB (in module curses):          Constants<6>.       (line  216)
* KEY_CLEAR (in module curses):          Constants<6>.       (line  189)
* KEY_CLOSE (in module curses):          Constants<6>.       (line  258)
* KEY_COMMAND (in module curses):        Constants<6>.       (line  261)
* KEY_COPY (in module curses):           Constants<6>.       (line  264)
* KEY_CREATE (in module curses):         Constants<6>.       (line  267)
* KEY_CREATE_LINK (in module winreg):    Access Rights.      (line   51)
* KEY_CREATE_SUB_KEY (in module winreg): Access Rights.      (line   38)
* KEY_CTAB (in module curses):           Constants<6>.       (line  213)
* KEY_DC (in module curses):             Constants<6>.       (line  180)
* KEY_DL (in module curses):             Constants<6>.       (line  174)
* KEY_DOWN (in module curses):           Constants<6>.       (line  149)
* KEY_EIC (in module curses):            Constants<6>.       (line  186)
* KEY_END (in module curses):            Constants<6>.       (line  270)
* KEY_ENTER (in module curses):          Constants<6>.       (line  219)
* KEY_ENUMERATE_SUB_KEYS (in module winreg): Access Rights.  (line   42)
* KEY_EOL (in module curses):            Constants<6>.       (line  195)
* KEY_EOS (in module curses):            Constants<6>.       (line  192)
* KEY_EXECUTE (in module winreg):        Access Rights.      (line   26)
* KEY_EXIT (in module curses):           Constants<6>.       (line  273)
* KEY_F0 (in module curses):             Constants<6>.       (line  167)
* KEY_FIND (in module curses):           Constants<6>.       (line  276)
* KEY_Fn (in module curses):             Constants<6>.       (line  171)
* KEY_HELP (in module curses):           Constants<6>.       (line  279)
* KEY_HOME (in module curses):           Constants<6>.       (line  161)
* KEY_IC (in module curses):             Constants<6>.       (line  183)
* KEY_IL (in module curses):             Constants<6>.       (line  177)
* KEY_LEFT (in module curses):           Constants<6>.       (line  155)
* KEY_LL (in module curses):             Constants<6>.       (line  231)
* KEY_MARK (in module curses):           Constants<6>.       (line  282)
* KEY_MAX (in module curses):            Constants<6>.       (line  423)
* KEY_MESSAGE (in module curses):        Constants<6>.       (line  285)
* KEY_MIN (in module curses):            Constants<6>.       (line  143)
* KEY_MOUSE (in module curses):          Constants<6>.       (line  417)
* KEY_MOVE (in module curses):           Constants<6>.       (line  288)
* KEY_NEXT (in module curses):           Constants<6>.       (line  291)
* KEY_NOTIFY (in module winreg):         Access Rights.      (line   46)
* KEY_NPAGE (in module curses):          Constants<6>.       (line  204)
* KEY_OPEN (in module curses):           Constants<6>.       (line  294)
* KEY_OPTIONS (in module curses):        Constants<6>.       (line  297)
* KEY_PPAGE (in module curses):          Constants<6>.       (line  207)
* KEY_PREVIOUS (in module curses):       Constants<6>.       (line  300)
* KEY_PRINT (in module curses):          Constants<6>.       (line  228)
* KEY_QUERY_VALUE (in module winreg):    Access Rights.      (line   30)
* KEY_READ (in module winreg):           Access Rights.      (line   20)
* KEY_REDO (in module curses):           Constants<6>.       (line  303)
* KEY_REFERENCE (in module curses):      Constants<6>.       (line  306)
* KEY_REFRESH (in module curses):        Constants<6>.       (line  309)
* KEY_REPLACE (in module curses):        Constants<6>.       (line  312)
* KEY_RESET (in module curses):          Constants<6>.       (line  225)
* KEY_RESIZE (in module curses):         Constants<6>.       (line  420)
* KEY_RESTART (in module curses):        Constants<6>.       (line  315)
* KEY_RESUME (in module curses):         Constants<6>.       (line  318)
* KEY_RIGHT (in module curses):          Constants<6>.       (line  158)
* KEY_SAVE (in module curses):           Constants<6>.       (line  321)
* KEY_SBEG (in module curses):           Constants<6>.       (line  324)
* KEY_SCANCEL (in module curses):        Constants<6>.       (line  327)
* KEY_SCOMMAND (in module curses):       Constants<6>.       (line  330)
* KEY_SCOPY (in module curses):          Constants<6>.       (line  333)
* KEY_SCREATE (in module curses):        Constants<6>.       (line  336)
* KEY_SDC (in module curses):            Constants<6>.       (line  339)
* KEY_SDL (in module curses):            Constants<6>.       (line  342)
* KEY_SELECT (in module curses):         Constants<6>.       (line  345)
* KEY_SEND (in module curses):           Constants<6>.       (line  348)
* KEY_SEOL (in module curses):           Constants<6>.       (line  351)
* KEY_SET_VALUE (in module winreg):      Access Rights.      (line   34)
* KEY_SEXIT (in module curses):          Constants<6>.       (line  354)
* KEY_SF (in module curses):             Constants<6>.       (line  198)
* KEY_SFIND (in module curses):          Constants<6>.       (line  357)
* KEY_SHELP (in module curses):          Constants<6>.       (line  360)
* KEY_SHOME (in module curses):          Constants<6>.       (line  363)
* KEY_SIC (in module curses):            Constants<6>.       (line  366)
* KEY_SLEFT (in module curses):          Constants<6>.       (line  369)
* KEY_SMESSAGE (in module curses):       Constants<6>.       (line  372)
* KEY_SMOVE (in module curses):          Constants<6>.       (line  375)
* KEY_SNEXT (in module curses):          Constants<6>.       (line  378)
* KEY_SOPTIONS (in module curses):       Constants<6>.       (line  381)
* KEY_SPREVIOUS (in module curses):      Constants<6>.       (line  384)
* KEY_SPRINT (in module curses):         Constants<6>.       (line  387)
* KEY_SR (in module curses):             Constants<6>.       (line  201)
* KEY_SREDO (in module curses):          Constants<6>.       (line  390)
* KEY_SREPLACE (in module curses):       Constants<6>.       (line  393)
* KEY_SRESET (in module curses):         Constants<6>.       (line  222)
* KEY_SRIGHT (in module curses):         Constants<6>.       (line  396)
* KEY_SRSUME (in module curses):         Constants<6>.       (line  399)
* KEY_SSAVE (in module curses):          Constants<6>.       (line  402)
* KEY_SSUSPEND (in module curses):       Constants<6>.       (line  405)
* KEY_STAB (in module curses):           Constants<6>.       (line  210)
* KEY_SUNDO (in module curses):          Constants<6>.       (line  408)
* KEY_SUSPEND (in module curses):        Constants<6>.       (line  411)
* KEY_UNDO (in module curses):           Constants<6>.       (line  414)
* KEY_UP (in module curses):             Constants<6>.       (line  152)
* KEY_WOW64_32KEY (in module winreg):    64-bit Specific.    (line   14)
* KEY_WOW64_64KEY (in module winreg):    64-bit Specific.    (line    8)
* KEY_WRITE (in module winreg):          Access Rights.      (line   15)
* key/value pair:                        Dictionary displays.
                                                             (line    6)
* KeyboardInterrupt:                     Concrete exceptions.
                                                             (line   91)
* KeyboardInterrupt (built-in exception): Signal Handling<2>.
                                                             (line    7)
* KeyboardInterrupt (built-in exception) <1>: Signal Handling<2>.
                                                             (line   46)
* KeyboardInterrupt (built-in exception) <2>: Signal Handling<2>.
                                                             (line   55)
* KeyError:                              Concrete exceptions.
                                                             (line   86)
* keylog_filename (ssl.SSLContext attribute): SSL contexts.  (line  526)
* keyname() (in module curses):          Functions<6>.       (line  262)
* keypad() (curses.window method):       Window Objects.     (line  381)
* keyrefs() (weakref.WeakKeyDictionary method): weakref — Weak references.
                                                             (line  208)
* keys() (contextvars.Context method):   Manual Context Management.
                                                             (line  133)
* keys() (dict method):                  Mapping Types — dict.
                                                             (line  191)
* keys() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  232)
* keys() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  341)
* keys() (mailbox.Mailbox method):       Mailbox objects.    (line  110)
* keys() (sqlite3.Row method):           Row objects.        (line   19)
* keys() (types.MappingProxyType method): Standard Interpreter Types.
                                                             (line  272)
* keys() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   76)
* KeysView (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  124)
* KeysView (class in typing):            Aliases to container ABCs in collections abc.
                                                             (line   64)
* keyword:                               Keywords.           (line    6)
* keyword <1>:                           Soft Keywords.      (line    6)
* keyword (class in ast):                Expressions<2>.     (line  151)
* keyword argument:                      Glossary.           (line  934)
* keyword; as:                           The import statement.
                                                             (line    6)
* keyword; as <1>:                       The try statement.  (line    6)
* keyword; as <2>:                       The with statement. (line    6)
* keyword; as <3>:                       The match statement.
                                                             (line    6)
* keyword; async:                        Coroutine function definition.
                                                             (line    9)
* keyword; await:                        Calls.              (line  159)
* keyword; await <1>:                    Coroutine function definition.
                                                             (line    9)
* keyword; case:                         The match statement.
                                                             (line    6)
* keyword; elif:                         The if statement.   (line    6)
* keyword; else:                         The break statement.
                                                             (line   12)
* keyword; else <1>:                     The if statement.   (line    6)
* keyword; else <2>:                     The while statement.
                                                             (line    6)
* keyword; else <3>:                     The for statement.  (line    6)
* keyword; else <4>:                     The try statement.  (line    6)
* keyword; else <5>:                     except* clause.     (line   66)
* keyword; except:                       The try statement.  (line    6)
* keyword; except_star:                  except clause.      (line   82)
* keyword; finally:                      The return statement.
                                                             (line   17)
* keyword; finally <1>:                  The break statement.
                                                             (line   18)
* keyword; finally <2>:                  The continue statement.
                                                             (line    6)
* keyword; finally <3>:                  The try statement.  (line    6)
* keyword; finally <4>:                  else clause.        (line   11)
* keyword; from:                         Yield expressions.  (line    6)
* keyword; from <1>:                     The import statement.
                                                             (line    6)
* keyword; if:                           The match statement.
                                                             (line    6)
* keyword; in:                           The for statement.  (line    6)
* keyword; yield:                        Yield expressions.  (line    6)
* keywords (functools.partial attribute): partial Objects.   (line   20)
* kill_python() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   77)
* kill() (asyncio.subprocess.Process method): Interacting with Subprocesses.
                                                             (line  106)
* kill() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   35)
* kill() (in module os):                 Process Management. (line  323)
* kill() (multiprocessing.Process method): Process and exceptions.
                                                             (line  221)
* kill() (subprocess.Popen method):      Popen Objects.      (line   99)
* killchar() (in module curses):         Functions<6>.       (line  272)
* killpg() (in module os):               Process Management. (line  345)
* kind (inspect.Parameter attribute):    Introspecting callables with the Signature object.
                                                             (line  227)
* knownfiles (in module mimetypes):      mimetypes — Map filenames to MIME types.
                                                             (line  135)
* kqueue() (in module select):           select — Waiting for I/O completion.
                                                             (line   97)
* KqueueSelector (class in selectors):   Classes<4>.         (line  195)
* KW_ONLY (in module dataclasses):       Module contents<5>. (line  486)
* kwargs (inspect.BoundArguments attribute): Introspecting callables with the Signature object.
                                                             (line  356)
* kwargs (typing.ParamSpec attribute):   Building generic types and type aliases.
                                                             (line  410)
* kwlist (in module keyword):            keyword — Testing for Python keywords.
                                                             (line   17)
* L (in module re):                      Flags.              (line   58)
* lambda:                                Glossary.           (line  938)
* Lambda (class in ast):                 Function and class definitions.
                                                             (line   32)
* lambda; expression:                    Lambdas.            (line    6)
* lambda; expression <1>:                Function definitions.
                                                             (line  128)
* lambda; form:                          Lambdas.            (line    6)
* LambdaType (in module types):          Standard Interpreter Types.
                                                             (line   25)
* LANG:                                  GNU gettext API.    (line   21)
* LANG <1>:                              Class-based API.    (line   26)
* LANG <2>:                              locale — Internationalization services.
                                                             (line   62)
* LANG <3>:                              locale — Internationalization services.
                                                             (line  358)
* LANG <4>:                              locale — Internationalization services.
                                                             (line  362)
* LANGUAGE:                              GNU gettext API.    (line   20)
* LANGUAGE <1>:                          Class-based API.    (line   25)
* large files:                           Large File Support. (line    6)
* LARGEST (in module test.support):      test support — Utilities for the Python test suite.
                                                             (line  184)
* LargeZipFile:                          zipfile — Work with ZIP archives.
                                                             (line   36)
* last_accepted (multiprocessing.connection.Listener attribute): Listeners and Clients.
                                                             (line  103)
* last_exc (in module sys):              sys — System-specific parameters and functions.
                                                             (line 1222)
* last_traceback (in module sys):        Traceback objects.  (line    6)
* last_traceback (in module sys) <1>:    sys — System-specific parameters and functions.
                                                             (line 1245)
* last_type (in module sys):             sys — System-specific parameters and functions.
                                                             (line 1245)
* last_value (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1245)
* lastChild (xml.dom.Node attribute):    Node Objects.       (line   59)
* lastcmd (cmd.Cmd attribute):           Cmd Objects.        (line  138)
* lastgroup (re.Match attribute):        Match Objects.      (line  200)
* lastindex (re.Match attribute):        Match Objects.      (line  192)
* lastResort (in module logging):        Module-Level Attributes.
                                                             (line    6)
* lastrowid (sqlite3.Cursor attribute):  Cursor objects.     (line  204)
* layout() (tkinter.ttk.Style method):   Ttk Styling.        (line   96)
* lazycache() (in module linecache):     linecache — Random access to text lines.
                                                             (line   50)
* LazyLoader (class in importlib.util):  importlib util – Utility code for importers.
                                                             (line  192)
* LBRACE (in module token):              token — Constants used with Python parse trees.
                                                             (line  230)
* LBYL:                                  Glossary.           (line  945)
* LC_ALL:                                GNU gettext API.    (line   20)
* LC_ALL <1>:                            Class-based API.    (line   25)
* LC_ALL (in module locale):             locale — Internationalization services.
                                                             (line  572)
* LC_COLLATE (in module locale):         locale — Internationalization services.
                                                             (line  538)
* LC_CTYPE (in module locale):           locale — Internationalization services.
                                                             (line  524)
* LC_MESSAGES:                           GNU gettext API.    (line   20)
* LC_MESSAGES <1>:                       Class-based API.    (line   26)
* LC_MESSAGES (in module locale):        locale — Internationalization services.
                                                             (line  554)
* LC_MONETARY (in module locale):        locale — Internationalization services.
                                                             (line  549)
* LC_NUMERIC (in module locale):         locale — Internationalization services.
                                                             (line  564)
* LC_TIME (in module locale):            locale — Internationalization services.
                                                             (line  544)
* lchflags() (in module os):             Files and Directories.
                                                             (line  305)
* lchmod() (in module os):               Files and Directories.
                                                             (line  319)
* lchmod() (pathlib.Path method):        Permissions and ownership.
                                                             (line   54)
* lchown() (in module os):               Files and Directories.
                                                             (line  340)
* lcm() (in module math):                Number-theoretic functions.
                                                             (line   56)
* ldexp() (in module math):              Floating point manipulation functions.
                                                             (line   77)
* LDFLAGS:                               New Improved and Deprecated Modules<4>.
                                                             (line   59)
* LDFLAGS <1>:                           Preprocessor flags. (line   18)
* LDFLAGS <2>:                           Linker flags.       (line   15)
* LDFLAGS <3>:                           Linker flags.       (line   18)
* LDFLAGS <4>:                           Linker flags.       (line   28)
* LDFLAGS <5>:                           Linker flags.       (line   31)
* LDFLAGS <6>:                           Linker flags.       (line   35)
* LDFLAGS <7>:                           Linker flags.       (line   50)
* LDFLAGS_NODIST:                        Linker flags.       (line   26)
* LDFLAGS_NODIST <1>:                    Linker flags.       (line   40)
* le() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* leading whitespace:                    Indentation.        (line    6)
* leapdays() (in module calendar):       calendar — General calendar-related functions.
                                                             (line  368)
* leaveok() (curses.window method):      Window Objects.     (line  388)
* left (filecmp.dircmp attribute):       The dircmp class.   (line   45)
* left_list (filecmp.dircmp attribute):  The dircmp class.   (line   53)
* left_only (filecmp.dircmp attribute):  The dircmp class.   (line   67)
* left() (in module turtle):             Turtle motion.      (line   57)
* LEFTSHIFT (in module token):           token — Constants used with Python parse trees.
                                                             (line  254)
* LEFTSHIFTEQUAL (in module token):      token — Constants used with Python parse trees.
                                                             (line  287)
* LEGACY_TRANSACTION_CONTROL (in module sqlite3): Module constants.
                                                             (line    6)
* lenfunc (C type):                      Slot Type typedefs. (line   96)
* length (xml.dom.NamedNodeMap attribute): NamedNodeMap Objects.
                                                             (line    8)
* length (xml.dom.NodeList attribute):   NodeList Objects.   (line   21)
* length_hint() (in module operator):    operator — Standard operators as functions.
                                                             (line  210)
* LESS (in module token):                token — Constants used with Python parse trees.
                                                             (line  215)
* LESSEQUAL (in module token):           token — Constants used with Python parse trees.
                                                             (line  242)
* level (logging.Logger attribute):      Logger Objects.     (line   33)
* lexical analysis:                      Lexical analysis.   (line    6)
* lexical analyzer:                      Glossary.           (line  960)
* lexical definitions:                   Notation.           (line   32)
* LexicalHandler (class in xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line   45)
* lexists() (in module os.path):         os path — Common pathname manipulations.
                                                             (line  130)
* LF (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   51)
* lgamma() (in module math):             Special functions.  (line   34)
* libc_ver() (in module platform):       Unix platforms.     (line    6)
* LIBRARIES_ASSEMBLY_NAME_PREFIX (in module msvcrt): Other Functions.
                                                             (line   98)
* library (in module dbm.ndbm):          dbm ndbm — New Database Manager.
                                                             (line   36)
* library (ssl.SSLError attribute):      Exceptions<16>.     (line   19)
* LibraryLoader (class in ctypes):       Loading shared libraries.
                                                             (line  169)
* license (built-in variable):           Constants added by the site module.
                                                             (line   32)
* LifoQueue (class in asyncio):          LIFO Queue.         (line    6)
* LifoQueue (class in queue):            queue — A synchronized queue class.
                                                             (line   40)
* light-weight processes:                _thread — Low-level threading API.
                                                             (line    6)
* limit_denominator() (fractions.Fraction method): fractions — Rational numbers.
                                                             (line  153)
* LimitOverrunError:                     Exceptions<13>.     (line   60)
* line (bdb.Breakpoint attribute):       bdb — Debugger framework.
                                                             (line   86)
* LINE (monitoring event):               Events.             (line   38)
* line (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   43)
* line continuation:                     Explicit line joining.
                                                             (line    6)
* line joining:                          Logical lines.      (line    6)
* line joining <1>:                      Explicit line joining.
                                                             (line    6)
* line structure:                        Line structure.     (line    6)
* line_buffering (io.TextIOWrapper attribute): Text I/O<2>.  (line  170)
* line_num (csv.csvreader attribute):    Reader Objects.     (line   23)
* line-buffered I/O:                     Built-in Functions. (line 1464)
* linear_regression() (in module statistics): Function details.
                                                             (line  628)
* lineno (ast.AST attribute):            Node classes.       (line   50)
* lineno (doctest.DocTest attribute):    DocTest Objects.    (line   41)
* lineno (doctest.Example attribute):    Example Objects.    (line   40)
* lineno (inspect.FrameInfo attribute):  The interpreter stack.
                                                             (line   22)
* lineno (inspect.Traceback attribute):  The interpreter stack.
                                                             (line   62)
* lineno (json.JSONDecodeError attribute): Exceptions<17>.   (line   23)
* lineno (netrc.NetrcParseError attribute): netrc — netrc file processing.
                                                             (line   60)
* lineno (pyclbr.Class attribute):       Class Objects<2>.   (line   24)
* lineno (pyclbr.Function attribute):    Function Objects.   (line   23)
* lineno (re.PatternError attribute):    Exceptions<3>.      (line   28)
* lineno (shlex.shlex attribute):        shlex Objects.      (line  169)
* lineno (SyntaxError attribute):        Concrete exceptions.
                                                             (line  320)
* lineno (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   34)
* lineno (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   95)
* lineno (tracemalloc.Filter attribute): Filter.             (line   49)
* lineno (tracemalloc.Frame attribute):  Frame.              (line   16)
* lineno (xml.parsers.expat.ExpatError attribute): ExpatError Exceptions.
                                                             (line   27)
* lineno() (in module fileinput):        fileinput — Iterate over lines from multiple input streams.
                                                             (line   97)
* LINES:                                 Functions<6>.       (line  125)
* LINES <1>:                             Functions<6>.       (line  593)
* LINES <2>:                             Functions<6>.       (line  595)
* LINES (in module curses):              Constants<6>.       (line   51)
* lines (os.terminal_size attribute):    Querying the size of a terminal.
                                                             (line   34)
* linesep (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  153)
* linesep (in module os):                Miscellaneous System Information.
                                                             (line  149)
* lineterminator (csv.Dialect attribute): Dialects and Formatting Parameters.
                                                             (line   54)
* LineTooLong:                           http client — HTTP protocol client.
                                                             (line  182)
* link() (in module os):                 Files and Directories.
                                                             (line  354)
* LinkFallbackError:                     tarfile — Read and write tar archive files.
                                                             (line  261)
* linkname (tarfile.TarInfo attribute):  TarInfo Objects.    (line   95)
* LinkOutsideDestinationError:           tarfile — Read and write tar archive files.
                                                             (line  256)
* list:                                  Glossary.           (line  964)
* list (built-in class):                 Lists<2>.           (line   10)
* List (class in ast):                   Literals<3>.        (line   66)
* List (class in typing):                Aliases to built-in types.
                                                             (line   18)
* list (pdb command):                    Debugger commands.  (line  239)
* list comprehension:                    Glossary.           (line  970)
* LIST_APPEND (opcode):                  Python Bytecode Instructions.
                                                             (line  381)
* list_dialects() (in module csv):       Module Contents<2>. (line   92)
* LIST_EXTEND (opcode):                  Python Bytecode Instructions.
                                                             (line  709)
* list_folders() (mailbox.Maildir method): Maildir objects.  (line   65)
* list_folders() (mailbox.MH method):    MH objects.         (line   35)
* list; comprehensions:                  List displays.      (line    6)
* list; display:                         List displays.      (line    6)
* list() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  126)
* list() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  231)
* list() (poplib.POP3 method):           POP3 Objects.       (line   57)
* list() (tarfile.TarFile method):       TarFile Objects.    (line  121)
* ListComp (class in ast):               Comprehensions.     (line    6)
* listdir() (in module os):              Files and Directories.
                                                             (line  376)
* listdrives() (in module os):           Files and Directories.
                                                             (line  413)
* listen() (in module logging.config):   Configuration functions.
                                                             (line  118)
* listen() (in module turtle):           Using screen events.
                                                             (line    6)
* listen() (socket.socket method):       Socket Objects.     (line  197)
* Listener (class in multiprocessing.connection): Listeners and Clients.
                                                             (line   50)
* listener (logging.handlers.QueueHandler attribute): QueueHandler.
                                                             (line   91)
* listMethods() (xmlrpc.client.ServerProxy.system method): ServerProxy Objects.
                                                             (line   17)
* listmounts() (in module os):           Files and Directories.
                                                             (line  432)
* listvolumes() (in module os):          Files and Directories.
                                                             (line  456)
* listxattr() (in module os):            Linux extended attributes.
                                                             (line   26)
* literal:                               Literals.           (line    6)
* literal <1>:                           Literals<2>.        (line    6)
* Literal (in module typing):            Special forms.      (line  132)
* literal_eval() (in module ast):        ast Helpers.        (line   84)
* LiteralString (in module typing):      Special types.      (line   67)
* LittleEndianStructure (class in ctypes): Structured data types.
                                                             (line   26)
* LittleEndianUnion (class in ctypes):   Structured data types.
                                                             (line   16)
* ljust() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  303)
* ljust() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  303)
* ljust() (str method):                  String Methods<2>.  (line  468)
* LK_LOCK (in module msvcrt):            File Operations.    (line   19)
* LK_NBLCK (in module msvcrt):           File Operations.    (line   27)
* LK_NBRLCK (in module msvcrt):          File Operations.    (line   27)
* LK_RLCK (in module msvcrt):            File Operations.    (line   19)
* LK_UNLCK (in module msvcrt):           File Operations.    (line   33)
* ll (pdb command):                      Debugger commands.  (line  255)
* LMTP (class in smtplib):               smtplib — SMTP protocol client.
                                                             (line  105)
* ln() (decimal.Context method):         Context objects.    (line  367)
* ln() (decimal.Decimal method):         Decimal objects.    (line  329)
* LNKTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  282)
* Load (class in ast):                   Variables.          (line   11)
* LOAD_ASSERTION_ERROR (opcode):         Python Bytecode Instructions.
                                                             (line  501)
* LOAD_ATTR (opcode):                    Python Bytecode Instructions.
                                                             (line  749)
* LOAD_BUILD_CLASS (opcode):             Python Bytecode Instructions.
                                                             (line  508)
* load_cert_chain() (ssl.SSLContext method): SSL contexts.   (line  101)
* LOAD_CLOSURE (opcode):                 Python Bytecode Instructions.
                                                             (line 1434)
* LOAD_CONST (opcode):                   Python Bytecode Instructions.
                                                             (line  633)
* load_default_certs() (ssl.SSLContext method): SSL contexts.
                                                             (line  132)
* LOAD_DEREF (opcode):                   Python Bytecode Instructions.
                                                             (line  977)
* load_dh_params() (ssl.SSLContext method): SSL contexts.    (line  352)
* load_extension() (sqlite3.Connection method): Connection objects.
                                                             (line  473)
* LOAD_FAST (opcode):                    Python Bytecode Instructions.
                                                             (line  915)
* LOAD_FAST_AND_CLEAR (opcode):          Python Bytecode Instructions.
                                                             (line  939)
* LOAD_FAST_CHECK (opcode):              Python Bytecode Instructions.
                                                             (line  931)
* LOAD_FAST_LOAD_FAST (opcode):          Python Bytecode Instructions.
                                                             (line  924)
* LOAD_FROM_DICT_OR_DEREF (opcode):      Python Bytecode Instructions.
                                                             (line  985)
* LOAD_FROM_DICT_OR_GLOBALS (opcode):    Python Bytecode Instructions.
                                                             (line  652)
* LOAD_GLOBAL (opcode):                  Python Bytecode Instructions.
                                                             (line  908)
* LOAD_LOCALS (opcode):                  Python Bytecode Instructions.
                                                             (line  643)
* LOAD_METHOD (opcode):                  Python Bytecode Instructions.
                                                             (line 1444)
* load_module() (importlib.abc.FileLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  310)
* load_module() (importlib.abc.InspectLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  263)
* load_module() (importlib.abc.Loader method): importlib abc – Abstract base classes related to import.
                                                             (line  126)
* load_module() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  410)
* load_module() (importlib.machinery.SourceFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  235)
* load_module() (importlib.machinery.SourcelessFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  279)
* load_module() (zipimport.zipimporter method): zipimporter Objects.
                                                             (line   79)
* LOAD_NAME (opcode):                    Python Bytecode Instructions.
                                                             (line  637)
* load_package_tests() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  627)
* LOAD_SUPER_ATTR (opcode):              Python Bytecode Instructions.
                                                             (line  767)
* load_verify_locations() (ssl.SSLContext method): SSL contexts.
                                                             (line  149)
* load() (http.cookiejar.FileCookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line  126)
* load() (http.cookies.BaseCookie method): Cookie Objects.   (line   39)
* load() (in module json):               Basic Usage.        (line  108)
* load() (in module marshal):            marshal — Internal Python object serialization.
                                                             (line   71)
* load() (in module pickle):             Module Interface.   (line   58)
* load() (in module plistlib):           plistlib — Generate and parse Apple plist files.
                                                             (line   46)
* load() (in module tomllib):            tomllib — Parse TOML files.
                                                             (line   32)
* load() (pickle.Unpickler method):      Module Interface.   (line  268)
* load() (tracemalloc.Snapshot class method): Snapshot.      (line   50)
* loader:                                Finders and loaders.
                                                             (line    6)
* loader <1>:                            Glossary.           (line 1006)
* Loader (class in importlib.abc):       importlib abc – Abstract base classes related to import.
                                                             (line   90)
* loader (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  386)
* loader_state (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  415)
* LoadError:                             http cookiejar — Cookie handling for HTTP clients.
                                                             (line   34)
* LoadFileDialog (class in tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line  135)
* LoadKey() (in module winreg):          Functions<13>.      (line  257)
* LoadLibrary() (ctypes.LibraryLoader method): Loading shared libraries.
                                                             (line  180)
* loads() (in module json):              Basic Usage.        (line  189)
* loads() (in module marshal):           marshal — Internal Python object serialization.
                                                             (line  110)
* loads() (in module pickle):            Module Interface.   (line   76)
* loads() (in module plistlib):          plistlib — Generate and parse Apple plist files.
                                                             (line   82)
* loads() (in module tomllib):           tomllib — Parse TOML files.
                                                             (line   48)
* loads() (in module xmlrpc.client):     Convenience Functions.
                                                             (line   19)
* loadTestsFromModule() (unittest.TestLoader method): Loading and running tests.
                                                             (line   40)
* loadTestsFromName() (unittest.TestLoader method): Loading and running tests.
                                                             (line   69)
* loadTestsFromNames() (unittest.TestLoader method): Loading and running tests.
                                                             (line  103)
* loadTestsFromTestCase() (unittest.TestLoader method): Loading and running tests.
                                                             (line   29)
* local (class in threading):            Thread-local data.  (line  127)
* LOCAL_CREDS (in module socket):        Constants<8>.       (line  321)
* LOCAL_CREDS_PERSISTENT (in module socket): Constants<8>.   (line  321)
* localcontext() (in module decimal):    Context objects.    (line   25)
* LOCALE (in module re):                 Flags.              (line   58)
* locale encoding:                       Glossary.           (line 1020)
* localeconv() (in module locale):       locale — Internationalization services.
                                                             (line   66)
* LocaleHTMLCalendar (class in calendar): calendar — General calendar-related functions.
                                                             (line  335)
* LocaleTextCalendar (class in calendar): calendar — General calendar-related functions.
                                                             (line  329)
* localize() (in module locale):         locale — Internationalization services.
                                                             (line  506)
* localName (xml.dom.Attr attribute):    Attr Objects.       (line   13)
* localName (xml.dom.Node attribute):    Node Objects.       (line   64)
* localtime() (in module email.utils):   email utils Miscellaneous utilities.
                                                             (line   13)
* localtime() (in module time):          Functions<5>.       (line  149)
* Locator (class in xml.sax.xmlreader):  xml sax xmlreader — Interface for XML parsers.
                                                             (line   43)
* lock:                                  Glossary.           (line  979)
* Lock (class in asyncio):               Lock.               (line    6)
* Lock (class in multiprocessing):       Synchronization primitives.
                                                             (line   58)
* Lock (class in threading):             Lock objects.       (line   32)
* lock (sys.thread_info attribute):      sys — System-specific parameters and functions.
                                                             (line 1934)
* LOCK_EX (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  188)
* LOCK_NB (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  192)
* LOCK_SH (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  184)
* LOCK_UN (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  180)
* lock-free:                             Glossary.           (line  994)
* lock, interpreter:                     Thread State and the Global Interpreter Lock.
                                                             (line    6)
* lock() (mailbox.Babyl method):         Babyl objects.      (line   59)
* lock() (mailbox.Mailbox method):       Mailbox objects.    (line  255)
* lock() (mailbox.Maildir method):       Maildir objects.    (line  209)
* lock() (mailbox.mbox method):          mbox objects.       (line   57)
* lock() (mailbox.MH method):            MH objects.         (line   87)
* lock() (mailbox.MMDF method):          MMDF objects.       (line   47)
* Lock() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  188)
* locked() (_thread.lock method):        _thread — Low-level threading API.
                                                             (line  175)
* locked() (asyncio.Condition method):   Condition.          (line   63)
* locked() (asyncio.Lock method):        Lock.               (line   58)
* locked() (asyncio.Semaphore method):   Semaphore.          (line   50)
* locked() (threading.Lock method):      Lock objects.       (line   86)
* lockf() (in module fcntl):             fcntl — The fcntl and ioctl system calls.
                                                             (line  173)
* lockf() (in module os):                File Descriptor Operations.
                                                             (line  265)
* locking() (in module msvcrt):          File Operations.    (line    6)
* LockType (in module _thread):          _thread — Low-level threading API.
                                                             (line   28)
* LOG_ALERT (in module syslog):          syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_AUTH (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_AUTHPRIV (in module syslog):       syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_CONS (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_CRIT (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_CRON (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_DAEMON (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* log_date_time_string() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  331)
* LOG_DEBUG (in module syslog):          syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_EMERG (in module syslog):          syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_ERR (in module syslog):            syslog — Unix syslog library routines.
                                                             (line  110)
* log_error() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  301)
* log_exception() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  210)
* LOG_FTP (in module syslog):            syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_INFO (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_INSTALL (in module syslog):        syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_KERN (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LAUNCHD (in module syslog):        syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL0 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL1 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL2 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL3 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL4 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL5 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL6 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LOCAL7 (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_LPR (in module syslog):            syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_MAIL (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* log_message() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  307)
* LOG_NDELAY (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_NETINFO (in module syslog):        syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_NEWS (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_NOTICE (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  110)
* LOG_NOWAIT (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_ODELAY (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_PERROR (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_PID (in module syslog):            syslog — Unix syslog library routines.
                                                             (line  156)
* LOG_RAS (in module syslog):            syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_REMOTEAUTH (in module syslog):     syslog — Unix syslog library routines.
                                                             (line  121)
* log_request() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  294)
* LOG_SYSLOG (in module syslog):         syslog — Unix syslog library routines.
                                                             (line  121)
* log_to_stderr() (in module multiprocessing): Logging<2>.   (line   24)
* LOG_USER (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_UUCP (in module syslog):           syslog — Unix syslog library routines.
                                                             (line  121)
* LOG_WARNING (in module syslog):        syslog — Unix syslog library routines.
                                                             (line  110)
* log() (in module cmath):               Power and logarithmic functions.
                                                             (line   11)
* log() (in module logging):             Module-Level Functions.
                                                             (line   99)
* log() (in module math):                Power exponential and logarithmic functions.
                                                             (line   40)
* log() (logging.Logger method):         Logger Objects.     (line  313)
* log10() (decimal.Context method):      Context objects.    (line  371)
* log10() (decimal.Decimal method):      Decimal objects.    (line  335)
* log10() (in module cmath):             Power and logarithmic functions.
                                                             (line   17)
* log10() (in module math):              Power exponential and logarithmic functions.
                                                             (line   67)
* log1p() (in module math):              Power exponential and logarithmic functions.
                                                             (line   48)
* log2() (in module math):               Power exponential and logarithmic functions.
                                                             (line   53)
* logb() (decimal.Context method):       Context objects.    (line  375)
* logb() (decimal.Decimal method):       Decimal objects.    (line  341)
* Logger (class in logging):             Logger Objects.     (line   24)
* LoggerAdapter (class in logging):      LoggerAdapter Objects.
                                                             (line   11)
* logical line:                          Logical lines.      (line    6)
* logical_and() (decimal.Context method): Context objects.   (line  379)
* logical_and() (decimal.Decimal method): Decimal objects.   (line  349)
* logical_invert() (decimal.Context method): Context objects.
                                                             (line  384)
* logical_invert() (decimal.Decimal method): Decimal objects.
                                                             (line  355)
* logical_or() (decimal.Context method): Context objects.    (line  388)
* logical_or() (decimal.Decimal method): Decimal objects.    (line  360)
* logical_xor() (decimal.Context method): Context objects.   (line  393)
* logical_xor() (decimal.Decimal method): Decimal objects.   (line  366)
* login_cram_md5() (imaplib.IMAP4 method): IMAP4 Objects.    (line  137)
* login_tty() (in module os):            File Descriptor Operations.
                                                             (line  291)
* login() (ftplib.FTP method):           FTP objects.        (line  127)
* login() (imaplib.IMAP4 method):        IMAP4 Objects.      (line  132)
* login() (smtplib.SMTP method):         SMTP Objects.       (line  102)
* LOGNAME:                               Process Parameters. (line  234)
* LOGNAME <1>:                           getpass — Portable password input.
                                                             (line   43)
* lognormvariate() (in module random):   Real-valued distributions.
                                                             (line   78)
* logout() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  146)
* LogRecord (class in logging):          LogRecord Objects.  (line   11)
* LONG_MAX (C macro):                    Integer Objects.    (line  152)
* LONG_TIMEOUT (in module test.support): test support — Utilities for the Python test suite.
                                                             (line   93)
* longMessage (unittest.TestCase attribute): Test cases.     (line  697)
* longname() (in module curses):         Functions<6>.       (line  279)
* lookup_error() (in module codecs):     Error Handlers.     (line  130)
* lookup() (in module codecs):           codecs — Codec registry and base classes.
                                                             (line   56)
* lookup() (in module unicodedata):      unicodedata — Unicode Database.
                                                             (line   22)
* lookup() (symtable.SymbolTable method): Examining Symbol Tables.
                                                             (line  108)
* lookup() (tkinter.ttk.Style method):   Ttk Styling.        (line   81)
* LookupError:                           Base classes.       (line   83)
* loop control; target:                  The break statement.
                                                             (line   12)
* loop_factory (unittest.IsolatedAsyncioTestCase attribute): Test cases.
                                                             (line  852)
* loop; over mutable sequence:           Common Sequence Operations.
                                                             (line   66)
* loop; statement:                       The break statement.
                                                             (line    6)
* loop; statement <1>:                   The continue statement.
                                                             (line    6)
* loop; statement <2>:                   The while statement.
                                                             (line    6)
* loop; statement <3>:                   The for statement.  (line    6)
* LOOPBACK_TIMEOUT (in module test.support): test support — Utilities for the Python test suite.
                                                             (line   48)
* lower() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  619)
* lower() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  619)
* lower() (str method):                  String Methods<2>.  (line  486)
* LPAR (in module token):                token — Constants used with Python parse trees.
                                                             (line  176)
* lpAttributeList (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   59)
* lru_cache() (in module functools):     functools — Higher-order functions and operations on callable objects.
                                                             (line  142)
* lseek() (in module os):                File Descriptor Operations.
                                                             (line  302)
* LShift (class in ast):                 Expressions<2>.     (line   53)
* lshift() (in module operator):         operator — Standard operators as functions.
                                                             (line  110)
* LSQB (in module token):                token — Constants used with Python parse trees.
                                                             (line  182)
* lstat() (in module os):                Files and Directories.
                                                             (line  477)
* lstat() (pathlib.Path method):         Querying file type and status.
                                                             (line   30)
* lstrip() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line  315)
* lstrip() (bytes method):               Bytes and Bytearray Operations.
                                                             (line  315)
* lstrip() (str method):                 String Methods<2>.  (line  497)
* lsub() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  153)
* Lt (class in ast):                     Expressions<2>.     (line  108)
* lt() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* lt() (in module turtle):               Turtle motion.      (line   57)
* LtE (class in ast):                    Expressions<2>.     (line  108)
* LWPCookieJar (class in http.cookiejar): FileCookieJar subclasses and co-operation with web browsers.
                                                             (line   28)
* LZMACompressor (class in lzma):        Compressing and decompressing data in memory.
                                                             (line    6)
* LZMADecompressor (class in lzma):      Compressing and decompressing data in memory.
                                                             (line   98)
* LZMAError:                             lzma — Compression using the LZMA algorithm.
                                                             (line   24)
* LZMAFile (class in lzma):              Reading and writing compressed files.
                                                             (line   45)
* M (in module re):                      Flags.              (line   82)
* mac_ver() (in module platform):        macOS platform.     (line    6)
* machine() (in module platform):        Cross platform.     (line   35)
* macros (netrc.netrc attribute):        netrc Objects.      (line   29)
* MADV_AUTOSYNC (in module mmap):        MADV_* Constants.   (line    6)
* MADV_CORE (in module mmap):            MADV_* Constants.   (line    6)
* MADV_DODUMP (in module mmap):          MADV_* Constants.   (line    6)
* MADV_DOFORK (in module mmap):          MADV_* Constants.   (line    6)
* MADV_DONTDUMP (in module mmap):        MADV_* Constants.   (line    6)
* MADV_DONTFORK (in module mmap):        MADV_* Constants.   (line    6)
* MADV_DONTNEED (in module mmap):        MADV_* Constants.   (line    6)
* MADV_FREE (in module mmap):            MADV_* Constants.   (line    6)
* MADV_FREE_REUSABLE (in module mmap):   MADV_* Constants.   (line    6)
* MADV_FREE_REUSE (in module mmap):      MADV_* Constants.   (line    6)
* MADV_HUGEPAGE (in module mmap):        MADV_* Constants.   (line    6)
* MADV_HWPOISON (in module mmap):        MADV_* Constants.   (line    6)
* MADV_MERGEABLE (in module mmap):       MADV_* Constants.   (line    6)
* MADV_NOCORE (in module mmap):          MADV_* Constants.   (line    6)
* MADV_NOHUGEPAGE (in module mmap):      MADV_* Constants.   (line    6)
* MADV_NORMAL (in module mmap):          MADV_* Constants.   (line    6)
* MADV_NOSYNC (in module mmap):          MADV_* Constants.   (line    6)
* MADV_PROTECT (in module mmap):         MADV_* Constants.   (line    6)
* MADV_RANDOM (in module mmap):          MADV_* Constants.   (line    6)
* MADV_REMOVE (in module mmap):          MADV_* Constants.   (line    6)
* MADV_SEQUENTIAL (in module mmap):      MADV_* Constants.   (line    6)
* MADV_SOFT_OFFLINE (in module mmap):    MADV_* Constants.   (line    6)
* MADV_UNMERGEABLE (in module mmap):     MADV_* Constants.   (line    6)
* MADV_WILLNEED (in module mmap):        MADV_* Constants.   (line    6)
* madvise() (mmap.mmap method):          mmap — Memory-mapped file support.
                                                             (line  224)
* magic method:                          Glossary.           (line 1034)
* MAGIC_NUMBER (in module importlib.util): importlib util – Utility code for importers.
                                                             (line   13)
* magic; method:                         Glossary.           (line 1038)
* MagicMock (class in unittest.mock):    Magic Mock.         (line    9)
* Mailbox (class in mailbox):            Mailbox objects.    (line    6)
* Maildir (class in mailbox):            Maildir objects.    (line    6)
* MaildirMessage (class in mailbox):     MaildirMessage objects.
                                                             (line    6)
* main_thread() (in module threading):   Reference<2>.       (line  106)
* main():                                Process-wide parameters.
                                                             (line    7)
* main() <1>:                            Process-wide parameters.
                                                             (line  218)
* main() <2>:                            PyConfig.           (line  127)
* main() (in module site):               Module contents<6>. (line   42)
* main() (in module unittest):           Loading and running tests.
                                                             (line  511)
* mainloop() (in module turtle):         Using screen events.
                                                             (line  106)
* maintype (email.headerregistry.ContentTypeHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  275)
* major (email.headerregistry.MIMEVersionHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  246)
* major() (in module os):                Files and Directories.
                                                             (line  622)
* make_alternative() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  607)
* make_archive() (in module shutil):     Archiving operations.
                                                             (line   14)
* make_bad_fd() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  105)
* MAKE_CELL (opcode):                    Python Bytecode Instructions.
                                                             (line  970)
* make_cookies() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   61)
* make_dataclass() (in module dataclasses): Module contents<5>.
                                                             (line  397)
* make_file() (difflib.HtmlDiff method): difflib — Helpers for computing deltas.
                                                             (line  111)
* MAKE_FUNCTION (opcode):                Python Bytecode Instructions.
                                                             (line 1109)
* make_header() (in module email.header): email header Internationalized headers.
                                                             (line  218)
* make_legacy_pyc() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   80)
* make_mixed() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  617)
* make_msgid() (in module email.utils):  email utils Miscellaneous utilities.
                                                             (line   27)
* make_parser() (in module xml.sax):     xml sax — Support for SAX2 parsers.
                                                             (line   27)
* make_pkg() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   97)
* make_related() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  598)
* make_script() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   82)
* make_server() (in module wsgiref.simple_server): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   14)
* make_table() (difflib.HtmlDiff method): difflib — Helpers for computing deltas.
                                                             (line  143)
* make_zip_pkg() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line  103)
* make_zip_script() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   89)
* makedev() (in module os):              Files and Directories.
                                                             (line  632)
* makedirs() (in module os):             Files and Directories.
                                                             (line  542)
* makeelement() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  163)
* makefile() (socket method):            I/O objects also known as file objects.
                                                             (line    6)
* makefile() (socket.socket method):     Socket Objects.     (line  209)
* makeLogRecord() (in module logging):   Module-Level Functions.
                                                             (line  196)
* makePickle() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   45)
* makeRecord() (logging.Logger method):  Logger Objects.     (line  374)
* makeSocket() (logging.handlers.DatagramHandler method): DatagramHandler.
                                                             (line   37)
* makeSocket() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   39)
* maketrans() (bytearray static method): Bytes and Bytearray Operations.
                                                             (line  176)
* maketrans() (bytes static method):     Bytes and Bytearray Operations.
                                                             (line  176)
* maketrans() (str static method):       String Methods<2>.  (line  519)
* MalformedHeaderDefect:                 email errors Exception and Defect classes.
                                                             (line  108)
* malloc (C function):                   Overview<4>.        (line   33)
* manager (logging.LoggerAdapter attribute): LoggerAdapter Objects.
                                                             (line   30)
* mangle_from_ (email.policy.Compat32 attribute): email policy Policy Objects.
                                                             (line  574)
* mangle_from_ (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  187)
* MANPAGER:                              pydoc — Documentation generator and online help system.
                                                             (line   46)
* MANPAGER <1>:                          pydoc — Documentation generator and online help system.
                                                             (line   48)
* mant_dig (sys.float_info attribute):   sys — System-specific parameters and functions.
                                                             (line  633)
* MAP_32BIT (in module mmap):            MAP_* Constants.    (line    6)
* MAP_ADD (opcode):                      Python Bytecode Instructions.
                                                             (line  390)
* MAP_ALIGNED_SUPER (in module mmap):    MAP_* Constants.    (line    6)
* MAP_ANON (in module mmap):             MAP_* Constants.    (line    6)
* MAP_ANONYMOUS (in module mmap):        MAP_* Constants.    (line    6)
* map_async() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line  113)
* MAP_CONCEAL (in module mmap):          MAP_* Constants.    (line    6)
* MAP_DENYWRITE (in module mmap):        MAP_* Constants.    (line    6)
* MAP_EXECUTABLE (in module mmap):       MAP_* Constants.    (line    6)
* MAP_HASSEMAPHORE (in module mmap):     MAP_* Constants.    (line    6)
* MAP_JIT (in module mmap):              MAP_* Constants.    (line    6)
* MAP_NOCACHE (in module mmap):          MAP_* Constants.    (line    6)
* MAP_NOEXTEND (in module mmap):         MAP_* Constants.    (line    6)
* MAP_NORESERVE (in module mmap):        MAP_* Constants.    (line    6)
* MAP_POPULATE (in module mmap):         MAP_* Constants.    (line    6)
* MAP_PRIVATE (in module mmap):          MAP_* Constants.    (line    6)
* MAP_RESILIENT_CODESIGN (in module mmap): MAP_* Constants.  (line    6)
* MAP_RESILIENT_MEDIA (in module mmap):  MAP_* Constants.    (line    6)
* MAP_SHARED (in module mmap):           MAP_* Constants.    (line    6)
* MAP_STACK (in module mmap):            MAP_* Constants.    (line    6)
* map_table_b2() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   49)
* map_table_b3() (in module stringprep): stringprep — Internet String Preparation.
                                                             (line   54)
* map_to_type() (email.headerregistry.HeaderRegistry method): email headerregistry Custom Header Objects.
                                                             (line  376)
* MAP_TPRO (in module mmap):             MAP_* Constants.    (line    6)
* MAP_TRANSLATED_ALLOW_EXECUTE (in module mmap): MAP_* Constants.
                                                             (line    6)
* MAP_UNIX03 (in module mmap):           MAP_* Constants.    (line    6)
* map() (concurrent.futures.Executor method): Executor Objects.
                                                             (line   22)
* map() (multiprocessing.pool.Pool method): Process Pools.   (line   96)
* map() (tkinter.ttk.Style method):      Ttk Styling.        (line   48)
* mapLogRecord() (logging.handlers.HTTPHandler method): HTTPHandler.
                                                             (line   27)
* mapping:                               Glossary.           (line 1038)
* Mapping (class in collections.abc):    Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  119)
* Mapping (class in typing):             Aliases to container ABCs in collections abc.
                                                             (line   72)
* MappingProxyType (class in types):     Standard Interpreter Types.
                                                             (line  224)
* MappingView (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  124)
* MappingView (class in typing):         Aliases to container ABCs in collections abc.
                                                             (line   80)
* mapPriority() (logging.handlers.SysLogHandler method): SysLogHandler.
                                                             (line  200)
* maps (collections.ChainMap attribute): ChainMap objects.   (line   39)
* MARCH (in module calendar):            calendar — General calendar-related functions.
                                                             (line  488)
* markcoroutinefunction() (in module inspect): Types and members.
                                                             (line  423)
* marshalling; objects:                  pickle — Python object serialization.
                                                             (line    8)
* masking; operations:                   Bitwise Operations on Integer Types.
                                                             (line    6)
* master (tkinter.Tk attribute):         Tkinter Modules.    (line   75)
* Match (class in ast):                  Pattern matching.   (line    6)
* Match (class in re):                   Match Objects.      (line   15)
* Match (class in typing):               Aliases to other concrete types.
                                                             (line    6)
* match_case (class in ast):             Pattern matching.   (line   15)
* MATCH_CLASS (opcode):                  Python Bytecode Instructions.
                                                             (line 1211)
* MATCH_KEYS (opcode):                   Python Bytecode Instructions.
                                                             (line  550)
* MATCH_MAPPING (opcode):                Python Bytecode Instructions.
                                                             (line  531)
* MATCH_SEQUENCE (opcode):               Python Bytecode Instructions.
                                                             (line  540)
* match_value() (test.support.Matcher method): test support — Utilities for the Python test suite.
                                                             (line  790)
* match; case:                           The match statement.
                                                             (line    6)
* match() (in module re):                Functions<2>.       (line   48)
* match() (pathlib.PurePath method):     Methods and properties.
                                                             (line  285)
* match() (re.Pattern method):           Regular Expression Objects.
                                                             (line   43)
* MatchAs (class in ast):                Pattern matching.   (line  293)
* MatchClass (class in ast):             Pattern matching.   (line  230)
* Matcher (class in test.support):       test support — Utilities for the Python test suite.
                                                             (line  784)
* matches() (test.support.Matcher method): test support — Utilities for the Python test suite.
                                                             (line  786)
* MatchMapping (class in ast):           Pattern matching.   (line  184)
* MatchOr (class in ast):                Pattern matching.   (line  333)
* MatchSequence (class in ast):          Pattern matching.   (line  114)
* MatchSingleton (class in ast):         Pattern matching.   (line   90)
* MatchStar (class in ast):              Pattern matching.   (line  144)
* MatchValue (class in ast):             Pattern matching.   (line   63)
* matmul() (in module operator):         operator — Standard operators as functions.
                                                             (line  125)
* MatMult (class in ast):                Expressions<2>.     (line   53)
* matrix multiplication:                 Binary arithmetic operations.
                                                             (line   26)
* max (datetime.date attribute):         date Objects.       (line  105)
* max (datetime.datetime attribute):     datetime Objects.   (line  292)
* max (datetime.time attribute):         time Objects.       (line   37)
* max (datetime.timedelta attribute):    timedelta Objects.  (line   98)
* max (sys.float_info attribute):        sys — System-specific parameters and functions.
                                                             (line  638)
* max_10_exp (sys.float_info attribute): sys — System-specific parameters and functions.
                                                             (line  647)
* max_count (email.headerregistry.BaseHeader attribute): email headerregistry Custom Header Objects.
                                                             (line   60)
* MAX_EMAX (in module decimal):          Constants<4>.       (line   16)
* max_exp (sys.float_info attribute):    sys — System-specific parameters and functions.
                                                             (line  642)
* MAX_INTERPOLATION_DEPTH (in module configparser): ConfigParser Objects.
                                                             (line  344)
* max_line_length (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  146)
* max_lines (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  266)
* max_mag() (decimal.Context method):    Context objects.    (line  402)
* max_mag() (decimal.Decimal method):    Decimal objects.    (line  379)
* max_memuse (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line  144)
* MAX_PREC (in module decimal):          Constants<4>.       (line   13)
* max_prefixlen (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   49)
* max_prefixlen (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   65)
* max_prefixlen (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  273)
* max_prefixlen (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  295)
* MAX_Py_ssize_t (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  140)
* MAX_WBITS (in module zlib):            zlib — Compression compatible with gzip.
                                                             (line  309)
* max() (decimal.Context method):        Context objects.    (line  398)
* max() (decimal.Decimal method):        Decimal objects.    (line  372)
* maxarray (reprlib.Repr attribute):     Repr Objects.       (line   22)
* maxdeque (reprlib.Repr attribute):     Repr Objects.       (line   22)
* maxdict (reprlib.Repr attribute):      Repr Objects.       (line   22)
* maxDiff (unittest.TestCase attribute): Test cases.         (line  714)
* maxfrozenset (reprlib.Repr attribute): Repr Objects.       (line   22)
* MAXIMUM_SUPPORTED (ssl.TLSVersion attribute): Constants<9>.
                                                             (line  565)
* maximum_version (ssl.SSLContext attribute): SSL contexts.  (line  537)
* maxlen (collections.deque attribute):  deque objects.      (line  120)
* maxlevel (reprlib.Repr attribute):     Repr Objects.       (line   17)
* maxlist (reprlib.Repr attribute):      Repr Objects.       (line   22)
* maxlong (reprlib.Repr attribute):      Repr Objects.       (line   34)
* maxother (reprlib.Repr attribute):     Repr Objects.       (line   47)
* maxset (reprlib.Repr attribute):       Repr Objects.       (line   22)
* maxsize (asyncio.Queue attribute):     Queue.              (line   23)
* maxsize (in module sys):               sys — System-specific parameters and functions.
                                                             (line 1253)
* maxstring (reprlib.Repr attribute):    Repr Objects.       (line   39)
* maxtuple (reprlib.Repr attribute):     Repr Objects.       (line   22)
* maxunicode (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1259)
* MAXYEAR (in module datetime):          Constants.          (line   13)
* MAY (in module calendar):              calendar — General calendar-related functions.
                                                             (line  488)
* MB_ICONASTERISK (in module winsound):  winsound — Sound-playing interface for Windows.
                                                             (line  136)
* MB_ICONEXCLAMATION (in module winsound): winsound — Sound-playing interface for Windows.
                                                             (line  140)
* MB_ICONHAND (in module winsound):      winsound — Sound-playing interface for Windows.
                                                             (line  144)
* MB_ICONQUESTION (in module winsound):  winsound — Sound-playing interface for Windows.
                                                             (line  148)
* MB_OK (in module winsound):            winsound — Sound-playing interface for Windows.
                                                             (line  152)
* mbox (class in mailbox):               mbox objects.       (line    6)
* mboxMessage (class in mailbox):        mboxMessage objects.
                                                             (line    6)
* md5() (in module hashlib):             Constructors.       (line   20)
* mean (statistics.NormalDist attribute): NormalDist objects.
                                                             (line   21)
* mean() (in module statistics):         Function details.   (line   10)
* measure() (tkinter.font.Font method):  tkinter font — Tkinter font wrapper.
                                                             (line   63)
* median (statistics.NormalDist attribute): NormalDist objects.
                                                             (line   26)
* median_grouped() (in module statistics): Function details. (line  274)
* median_high() (in module statistics):  Function details.   (line  256)
* median_low() (in module statistics):   Function details.   (line  238)
* median() (in module statistics):       Function details.   (line  211)
* member_names (enum.EnumDict attribute): Data types.        (line  793)
* member() (in module enum):             Utilities and decorators.
                                                             (line   80)
* MemberDescriptorType (in module types): Standard Interpreter Types.
                                                             (line  208)
* membership; test:                      Membership test operations.
                                                             (line   36)
* memfd_create() (in module os):         Files and Directories.
                                                             (line 1797)
* memmove() (in module ctypes):          Utility functions.  (line  169)
* MemoryBIO (class in ssl):              Memory BIO support. (line  134)
* MemoryError:                           Concrete exceptions.
                                                             (line  107)
* MemoryHandler (class in logging.handlers): MemoryHandler.  (line   41)
* memoryview (built-in class):           Memory Views.       (line   10)
* memset() (in module ctypes):           Utility functions.  (line  175)
* merge() (in module heapq):             heapq — Heap queue algorithm.
                                                             (line   82)
* message (BaseExceptionGroup attribute): Exception groups.  (line   36)
* Message (class in email.message):      email message Message Representing an email message using the compat32 API.
                                                             (line   49)
* Message (class in mailbox):            Message objects.    (line    6)
* Message (class in tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line   21)
* message digest, MD5:                   hashlib — Secure hashes and message digests.
                                                             (line    8)
* message_factory (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  196)
* message_from_binary_file() (in module email): Parser API.  (line  129)
* message_from_bytes() (in module email): Parser API.        (line  116)
* message_from_file() (in module email): Parser API.         (line  152)
* message_from_string() (in module email): Parser API.       (line  142)
* MessageBeep() (in module winsound):    winsound — Sound-playing interface for Windows.
                                                             (line   33)
* MessageClass (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  172)
* MessageDefect:                         email errors Exception and Defect classes.
                                                             (line   55)
* MessageError:                          email errors Exception and Defect classes.
                                                             (line   13)
* MessageParseError:                     email errors Exception and Defect classes.
                                                             (line   19)
* messages (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   22)
* meta hooks:                            Import hooks.       (line    6)
* meta path finder:                      Glossary.           (line 1048)
* meta_path (in module sys):             sys — System-specific parameters and functions.
                                                             (line 1269)
* meta() (in module curses):             Functions<6>.       (line  286)
* metaclass:                             Metaclasses.        (line    6)
* metaclass <1>:                         Glossary.           (line 1057)
* metaclass hint:                        Determining the appropriate metaclass.
                                                             (line    6)
* metadata() (in module importlib.metadata): Distribution metadata.
                                                             (line    6)
* MetaPathFinder (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line   26)
* metavar (optparse.Option attribute):   Option attributes.  (line   88)
* MetavarTypeHelpFormatter (class in argparse): formatter_class.
                                                             (line   10)
* METH_CLASS (C macro):                  Implementing functions and methods.
                                                             (line  193)
* METH_COEXIST (C macro):                Implementing functions and methods.
                                                             (line  212)
* METH_FASTCALL (C macro):               Implementing functions and methods.
                                                             (line  123)
* METH_KEYWORDS (C macro):               Implementing functions and methods.
                                                             (line  107)
* METH_METHOD (C macro):                 Implementing functions and methods.
                                                             (line  150)
* METH_NOARGS (C macro):                 Implementing functions and methods.
                                                             (line  168)
* METH_O (C macro):                      Implementing functions and methods.
                                                             (line  180)
* METH_STATIC (C macro):                 Implementing functions and methods.
                                                             (line  201)
* METH_VARARGS (C macro):                Implementing functions and methods.
                                                             (line   97)
* method:                                Glossary.           (line 1072)
* method (urllib.request.Request attribute): Request Objects.
                                                             (line   52)
* method resolution order:               Glossary.           (line 1080)
* method_calls (unittest.mock.Mock attribute): The Mock Class.
                                                             (line  503)
* method; call:                          Calls.              (line  142)
* methodcaller() (in module operator):   operator — Standard operators as functions.
                                                             (line  321)
* MethodDescriptorType (in module types): Standard Interpreter Types.
                                                             (line  109)
* methodHelp() (xmlrpc.client.ServerProxy.system method): ServerProxy Objects.
                                                             (line   43)
* methods (pyclbr.Class attribute):      Class Objects<2>.   (line   50)
* methodSignature() (xmlrpc.client.ServerProxy.system method): ServerProxy Objects.
                                                             (line   22)
* MethodType (in module types):          Standard Interpreter Types.
                                                             (line   77)
* MethodType (in module types) <1>:      Function Objects<3>.
                                                             (line   14)
* MethodType (in module types) <2>:      Method Objects<2>.  (line   12)
* MethodWrapperType (in module types):   Standard Interpreter Types.
                                                             (line   96)
* metrics() (tkinter.font.Font method):  tkinter font — Tkinter font wrapper.
                                                             (line   69)
* MFD_ALLOW_SEALING (in module os):      Files and Directories.
                                                             (line 1815)
* MFD_CLOEXEC (in module os):            Files and Directories.
                                                             (line 1815)
* MFD_HUGE_16GB (in module os):          Files and Directories.
                                                             (line 1815)
* MFD_HUGE_16MB (in module os):          Files and Directories.
                                                             (line 1815)
* MFD_HUGE_1GB (in module os):           Files and Directories.
                                                             (line 1815)
* MFD_HUGE_1MB (in module os):           Files and Directories.
                                                             (line 1815)
* MFD_HUGE_256MB (in module os):         Files and Directories.
                                                             (line 1815)
* MFD_HUGE_2GB (in module os):           Files and Directories.
                                                             (line 1815)
* MFD_HUGE_2MB (in module os):           Files and Directories.
                                                             (line 1815)
* MFD_HUGE_32MB (in module os):          Files and Directories.
                                                             (line 1815)
* MFD_HUGE_512KB (in module os):         Files and Directories.
                                                             (line 1815)
* MFD_HUGE_512MB (in module os):         Files and Directories.
                                                             (line 1815)
* MFD_HUGE_64KB (in module os):          Files and Directories.
                                                             (line 1815)
* MFD_HUGE_8MB (in module os):           Files and Directories.
                                                             (line 1815)
* MFD_HUGE_MASK (in module os):          Files and Directories.
                                                             (line 1815)
* MFD_HUGE_SHIFT (in module os):         Files and Directories.
                                                             (line 1815)
* MFD_HUGETLB (in module os):            Files and Directories.
                                                             (line 1815)
* MH (class in mailbox):                 MH objects.         (line    6)
* MHMessage (class in mailbox):          MHMessage objects.  (line    6)
* microsecond (datetime.datetime attribute): datetime Objects.
                                                             (line  329)
* microsecond (datetime.time attribute): time Objects.       (line   62)
* microseconds (datetime.timedelta attribute): timedelta Objects.
                                                             (line  134)
* MIME; base64 encoding:                 base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line    8)
* MIME; content type:                    mimetypes — Map filenames to MIME types.
                                                             (line    8)
* MIME; headers:                         mimetypes — Map filenames to MIME types.
                                                             (line   25)
* MIME; headers <1>:                     mimetypes — Map filenames to MIME types.
                                                             (line   56)
* MIME; quoted-printable encoding:       quopri — Encode and decode MIME quoted-printable data.
                                                             (line    8)
* MIMEApplication (class in email.mime.application): email mime Creating email and MIME objects from scratch.
                                                             (line   95)
* MIMEAudio (class in email.mime.audio): email mime Creating email and MIME objects from scratch.
                                                             (line  125)
* MIMEBase (class in email.mime.base):   email mime Creating email and MIME objects from scratch.
                                                             (line   30)
* MIMEImage (class in email.mime.image): email mime Creating email and MIME objects from scratch.
                                                             (line  157)
* MIMEMessage (class in email.mime.message): email mime Creating email and MIME objects from scratch.
                                                             (line  190)
* MIMEMultipart (class in email.mime.multipart): email mime Creating email and MIME objects from scratch.
                                                             (line   66)
* MIMENonMultipart (class in email.mime.nonmultipart): email mime Creating email and MIME objects from scratch.
                                                             (line   55)
* MIMEPart (class in email.message):     email message Representing an email message.
                                                             (line  717)
* MIMEText (class in email.mime.text):   email mime Creating email and MIME objects from scratch.
                                                             (line  208)
* MimeTypes (class in mimetypes):        MimeTypes Objects.  (line   10)
* MIMEVersionHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  233)
* min (datetime.date attribute):         date Objects.       (line  101)
* min (datetime.datetime attribute):     datetime Objects.   (line  287)
* min (datetime.time attribute):         time Objects.       (line   33)
* min (datetime.timedelta attribute):    timedelta Objects.  (line   93)
* min (sys.float_info attribute):        sys — System-specific parameters and functions.
                                                             (line  652)
* min_10_exp (sys.float_info attribute): sys — System-specific parameters and functions.
                                                             (line  665)
* MIN_EMIN (in module decimal):          Constants<4>.       (line   19)
* MIN_ETINY (in module decimal):         Constants<4>.       (line   22)
* min_exp (sys.float_info attribute):    sys — System-specific parameters and functions.
                                                             (line  660)
* min_mag() (decimal.Context method):    Context objects.    (line  410)
* min_mag() (decimal.Decimal method):    Decimal objects.    (line  391)
* min() (decimal.Context method):        Context objects.    (line  406)
* min() (decimal.Decimal method):        Decimal objects.    (line  384)
* MINEQUAL (in module token):            token — Constants used with Python parse trees.
                                                             (line  266)
* MINIMUM_SUPPORTED (ssl.TLSVersion attribute): Constants<9>.
                                                             (line  563)
* minimum_version (ssl.SSLContext attribute): SSL contexts.  (line  555)
* minor (email.headerregistry.MIMEVersionHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  250)
* minor() (in module os):                Files and Directories.
                                                             (line  627)
* minus:                                 Unary arithmetic and bitwise operations.
                                                             (line   10)
* MINUS (in module token):               token — Constants used with Python parse trees.
                                                             (line  200)
* minus() (decimal.Context method):      Context objects.    (line  414)
* minute (datetime.datetime attribute):  datetime Objects.   (line  321)
* minute (datetime.time attribute):      time Objects.       (line   54)
* MINYEAR (in module datetime):          Constants.          (line    8)
* mirrored() (in module unicodedata):    unicodedata — Unicode Database.
                                                             (line  114)
* misc_header (cmd.Cmd attribute):       Cmd Objects.        (line  159)
* MisplacedEnvelopeHeaderDefect:         email errors Exception and Defect classes.
                                                             (line   96)
* MISSING (contextvars.Token attribute): Context Variables.  (line   97)
* MISSING (in module dataclasses):       Module contents<5>. (line  482)
* MISSING (in module sys.monitoring):    Callback function arguments.
                                                             (line    6)
* MISSING_C_DOCSTRINGS (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  154)
* missing_compiler_executable() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  673)
* MissingHeaderBodySeparatorDefect:      email errors Exception and Defect classes.
                                                             (line  100)
* MissingSectionHeaderError:             Exceptions<8>.      (line   60)
* mkd() (ftplib.FTP method):             FTP objects.        (line  339)
* mkdir() (in module os):                Files and Directories.
                                                             (line  509)
* mkdir() (pathlib.Path method):         Creating files and directories.
                                                             (line   21)
* mkdir() (zipfile.ZipFile method):      ZipFile objects.    (line  335)
* mkdtemp() (in module tempfile):        tempfile — Generate temporary files and directories.
                                                             (line  288)
* mkfifo() (in module os):               Files and Directories.
                                                             (line  581)
* mknod() (in module os):                Files and Directories.
                                                             (line  602)
* mkstemp() (in module tempfile):        tempfile — Generate temporary files and directories.
                                                             (line  229)
* mktemp() (in module tempfile):         Deprecated functions and variables.
                                                             (line   15)
* mktime_tz() (in module email.utils):   email utils Miscellaneous utilities.
                                                             (line  145)
* mktime() (in module time):             Functions<5>.       (line  162)
* mlsd() (ftplib.FTP method):            FTP objects.        (line  285)
* mmap (class in mmap):                  mmap — Memory-mapped file support.
                                                             (line   54)
* MMDF (class in mailbox):               MMDF objects.       (line    6)
* MMDFMessage (class in mailbox):        MMDFMessage objects.
                                                             (line    6)
* Mock (class in unittest.mock):         The Mock Class.     (line   24)
* mock_add_spec() (unittest.mock.Mock method): The Mock Class.
                                                             (line  247)
* mock_calls (unittest.mock.Mock attribute): The Mock Class. (line  521)
* mock_open() (in module unittest.mock): mock_open.          (line    6)
* Mod (class in ast):                    Expressions<2>.     (line   53)
* mod() (in module operator):            operator — Standard operators as functions.
                                                             (line  115)
* mode (bz2.BZ2File attribute):          De compression of files.
                                                             (line  128)
* mode (gzip.GzipFile attribute):        gzip — Support for gzip files.
                                                             (line  141)
* mode (io.FileIO attribute):            Raw File I/O.       (line   55)
* mode (lzma.LZMAFile attribute):        Reading and writing compressed files.
                                                             (line   98)
* mode (statistics.NormalDist attribute): NormalDist objects.
                                                             (line   31)
* mode (tarfile.TarInfo attribute):      TarInfo Objects.    (line   78)
* mode() (in module statistics):         Function details.   (line  323)
* mode() (in module turtle):             Settings and special methods.
                                                             (line    6)
* modf() (in module math):               Floating point arithmetic.
                                                             (line   55)
* modified() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   45)
* modify() (select.devpoll method):      /dev/poll Polling Objects.
                                                             (line   49)
* modify() (select.epoll method):        Edge and Level Trigger Polling epoll Objects.
                                                             (line   85)
* modify() (select.poll method):         Polling Objects.    (line   60)
* modify() (selectors.BaseSelector method): Classes<4>.      (line   94)
* module:                                Glossary.           (line 1087)
* Module (class in ast):                 Root nodes.         (line    6)
* module (pyclbr.Class attribute):       Class Objects<2>.   (line   16)
* module (pyclbr.Function attribute):    Function Objects.   (line   15)
* MODULE (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   11)
* Module browser:                        File menu Shell and Editor.
                                                             (line   22)
* module spec:                           Finders and loaders.
                                                             (line    6)
* module spec <1>:                       Glossary.           (line 1096)
* module_from_spec() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  121)
* module; __future__:                    __future__ — Future statement definitions.
                                                             (line    6)
* module; __main__:                      Resolution of names.
                                                             (line   53)
* module; __main__ <1>:                  Complete Python programs.
                                                             (line    6)
* module; __main__ <2>:                  Complete Python programs.
                                                             (line   19)
* module; __main__ <3>:                  __main__ — Top-level code environment.
                                                             (line    6)
* module; __main__ <4>:                  runpy — Locating and executing Python modules.
                                                             (line   29)
* module; __main__ <5>:                  runpy — Locating and executing Python modules.
                                                             (line  100)
* module; __main__ <6>:                  Embedding Python<2>.
                                                             (line   12)
* module; __main__ <7>:                  Initializing and finalizing the interpreter.
                                                             (line    7)
* module; __main__ <8>:                  Sub-interpreter support.
                                                             (line  112)
* module; __main__ <9>:                  Sub-interpreter support.
                                                             (line  197)
* module; _locale:                       locale — Internationalization services.
                                                             (line   16)
* module; _thread:                       _thread — Low-level threading API.
                                                             (line    6)
* module; _thread <1>:                   High-level API.     (line   53)
* module; _tkinter:                      Tkinter Modules.    (line  148)
* module; abc:                           abc — Abstract Base Classes.
                                                             (line    6)
* module; aifc:                          aifc — Read and write AIFF and AIFC files.
                                                             (line    6)
* module; argparse:                      argparse — Parser for command-line options arguments and subcommands.
                                                             (line    6)
* module; array:                         Mutable sequences.  (line   10)
* module; array <1>:                     Binary Sequence Types — bytes bytearray memoryview.
                                                             (line    6)
* module; array <2>:                     array — Efficient arrays of numeric values.
                                                             (line    6)
* module; ast:                           ast — Abstract Syntax Trees.
                                                             (line    6)
* module; asynchat:                      asynchat — Asynchronous socket command/response handler.
                                                             (line    6)
* module; asyncio:                       asyncio — Asynchronous I/O.
                                                             (line    6)
* module; asyncore:                      asyncore — Asynchronous socket handler.
                                                             (line    6)
* module; atexit:                        atexit — Exit handlers.
                                                             (line    6)
* module; audioop:                       audioop — Manipulate raw audio data.
                                                             (line    6)
* module; base64:                        base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line    6)
* module; base64 <1>:                    binascii — Convert between binary and ASCII.
                                                             (line    6)
* module; bdb:                           bdb — Debugger framework.
                                                             (line    6)
* module; bdb <1>:                       pdb — The Python Debugger.
                                                             (line   17)
* module; binascii:                      binascii — Convert between binary and ASCII.
                                                             (line    6)
* module; bisect:                        bisect — Array bisection algorithm.
                                                             (line    6)
* module; builtins:                      The dir Function.   (line   47)
* module; builtins <1>:                  Complete Python programs.
                                                             (line    6)
* module; builtins <2>:                  Built-in Functions. (line 2173)
* module; builtins <3>:                  builtins — Built-in objects.
                                                             (line    6)
* module; builtins <4>:                  Embedding Python<2>.
                                                             (line   12)
* module; builtins <5>:                  Initializing and finalizing the interpreter.
                                                             (line    7)
* module; builtins <6>:                  Sub-interpreter support.
                                                             (line  112)
* module; builtins <7>:                  Sub-interpreter support.
                                                             (line  197)
* module; bz2:                           bz2 — Support for bzip2 compression.
                                                             (line    6)
* module; calendar:                      calendar — General calendar-related functions.
                                                             (line    6)
* module; cgi:                           cgi — Common Gateway Interface support.
                                                             (line    6)
* module; cgitb:                         cgitb — Traceback manager for CGI scripts.
                                                             (line    6)
* module; chunk:                         chunk — Read IFF chunked data.
                                                             (line    6)
* module; cmath:                         cmath — Mathematical functions for complex numbers.
                                                             (line    6)
* module; cmd:                           cmd — Support for line-oriented command interpreters.
                                                             (line    6)
* module; cmd <1>:                       pdb — The Python Debugger.
                                                             (line   17)
* module; code:                          code — Interpreter base classes.
                                                             (line    6)
* module; codecs:                        codecs — Codec registry and base classes.
                                                             (line    6)
* module; codeop:                        codeop — Compile Python code.
                                                             (line    6)
* module; collections:                   Mutable sequences.  (line   11)
* module; collections <1>:               collections — Container datatypes.
                                                             (line    6)
* module; collections.abc:               collections abc — Abstract Base Classes for Containers.
                                                             (line    6)
* module; colorsys:                      colorsys — Conversions between color systems.
                                                             (line    6)
* module; compileall:                    compileall — Byte-compile Python libraries.
                                                             (line    6)
* module; concurrent.futures:            concurrent futures — Launching parallel tasks.
                                                             (line    6)
* module; configparser:                  configparser — Configuration file parser.
                                                             (line    6)
* module; contextlib:                    contextlib — Utilities for with-statement contexts.
                                                             (line    6)
* module; contextvars:                   contextvars — Context Variables.
                                                             (line    6)
* module; copy:                          copy — Shallow and deep copy operations.
                                                             (line    6)
* module; copy <1>:                      copyreg — Register pickle support functions.
                                                             (line    8)
* module; copyreg:                       copyreg — Register pickle support functions.
                                                             (line    6)
* module; cProfile:                      profile and cProfile Module Reference.
                                                             (line    6)
* module; crypt:                         crypt — Function to check Unix passwords.
                                                             (line    6)
* module; csv:                           csv — CSV File Reading and Writing.
                                                             (line    6)
* module; ctypes:                        ctypes — A foreign function library for Python.
                                                             (line    6)
* module; curses:                        curses — Terminal handling for character-cell displays.
                                                             (line    6)
* module; curses.ascii:                  curses ascii — Utilities for ASCII characters.
                                                             (line    6)
* module; curses.panel:                  curses panel — A panel stack extension for curses.
                                                             (line    6)
* module; curses.textpad:                curses textpad — Text input widget for curses programs.
                                                             (line    6)
* module; dataclasses:                   dataclasses — Data Classes.
                                                             (line    6)
* module; datetime:                      datetime — Basic date and time types.
                                                             (line    6)
* module; dbm:                           dbm — Interfaces to Unix “databases”.
                                                             (line    6)
* module; dbm.dumb:                      dbm dumb — Portable DBM implementation.
                                                             (line    6)
* module; dbm.gnu:                       Dictionaries<2>.    (line   25)
* module; dbm.gnu <1>:                   Restrictions.       (line    6)
* module; dbm.gnu <2>:                   dbm gnu — GNU database manager.
                                                             (line    6)
* module; dbm.ndbm:                      Dictionaries<2>.    (line   25)
* module; dbm.ndbm <1>:                  Restrictions.       (line    6)
* module; dbm.ndbm <2>:                  dbm ndbm — New Database Manager.
                                                             (line    6)
* module; dbm.sqlite3:                   dbm sqlite3 — SQLite backend for dbm.
                                                             (line    6)
* module; decimal:                       decimal — Decimal fixed-point and floating-point arithmetic.
                                                             (line    6)
* module; difflib:                       difflib — Helpers for computing deltas.
                                                             (line    6)
* module; dis:                           dis — Disassembler for Python bytecode.
                                                             (line    6)
* module; distutils:                     distutils — Building and installing Python modules.
                                                             (line    6)
* module; doctest:                       doctest — Test interactive Python examples.
                                                             (line    6)
* module; email:                         email — An email and MIME handling package.
                                                             (line    6)
* module; email.charset:                 email charset Representing character sets.
                                                             (line    6)
* module; email.contentmanager:          email contentmanager Managing MIME Content.
                                                             (line    6)
* module; email.encoders:                email encoders Encoders.
                                                             (line    6)
* module; email.errors:                  email errors Exception and Defect classes.
                                                             (line    6)
* module; email.generator:               email generator Generating MIME documents.
                                                             (line    6)
* module; email.header:                  email header Internationalized headers.
                                                             (line    6)
* module; email.headerregistry:          email headerregistry Custom Header Objects.
                                                             (line    6)
* module; email.iterators:               email iterators Iterators.
                                                             (line    6)
* module; email.message:                 email message Representing an email message.
                                                             (line    6)
* module; email.mime:                    email mime Creating email and MIME objects from scratch.
                                                             (line    6)
* module; email.mime.application:        email mime Creating email and MIME objects from scratch.
                                                             (line   95)
* module; email.mime.audio:              email mime Creating email and MIME objects from scratch.
                                                             (line  125)
* module; email.mime.base:               email mime Creating email and MIME objects from scratch.
                                                             (line   30)
* module; email.mime.image:              email mime Creating email and MIME objects from scratch.
                                                             (line  157)
* module; email.mime.message:            email mime Creating email and MIME objects from scratch.
                                                             (line  190)
* module; email.mime.multipart:          email mime Creating email and MIME objects from scratch.
                                                             (line   66)
* module; email.mime.nonmultipart:       email mime Creating email and MIME objects from scratch.
                                                             (line   55)
* module; email.mime.text:               email mime Creating email and MIME objects from scratch.
                                                             (line  208)
* module; email.parser:                  email parser Parsing email messages.
                                                             (line    6)
* module; email.policy:                  email policy Policy Objects.
                                                             (line    6)
* module; email.utils:                   email utils Miscellaneous utilities.
                                                             (line    6)
* module; encodings:                     encodings — Encodings package.
                                                             (line    6)
* module; encodings.idna:                encodings idna — Internationalized Domain Names in Applications.
                                                             (line    6)
* module; encodings.mbcs:                encodings mbcs — Windows ANSI codepage.
                                                             (line    6)
* module; encodings.utf_8_sig:           encodings utf_8_sig — UTF-8 codec with BOM signature.
                                                             (line    6)
* module; ensurepip:                     ensurepip — Bootstrapping the pip installer.
                                                             (line    6)
* module; enum:                          enum — Support for enumerations.
                                                             (line    6)
* module; errno:                         Concrete exceptions.
                                                             (line  155)
* module; errno <1>:                     errno — Standard errno system symbols.
                                                             (line    6)
* module; faulthandler:                  faulthandler — Dump the Python traceback.
                                                             (line    6)
* module; fcntl:                         fcntl — The fcntl and ioctl system calls.
                                                             (line    6)
* module; filecmp:                       filecmp — File and Directory Comparisons.
                                                             (line    6)
* module; fileinput:                     fileinput — Iterate over lines from multiple input streams.
                                                             (line    6)
* module; fnmatch:                       fnmatch — Unix filename pattern matching.
                                                             (line    6)
* module; fractions:                     fractions — Rational numbers.
                                                             (line    6)
* module; ftplib:                        ftplib — FTP protocol client.
                                                             (line    6)
* module; functools:                     functools — Higher-order functions and operations on callable objects.
                                                             (line    6)
* module; gc:                            gc — Garbage Collector interface.
                                                             (line    6)
* module; getopt:                        getopt — C-style parser for command line options.
                                                             (line    6)
* module; getpass:                       getpass — Portable password input.
                                                             (line    6)
* module; gettext:                       gettext — Multilingual internationalization services.
                                                             (line    6)
* module; glob:                          glob — Unix style pathname pattern expansion.
                                                             (line    6)
* module; glob <1>:                      fnmatch — Unix filename pattern matching.
                                                             (line   34)
* module; graphlib:                      graphlib — Functionality to operate with graph-like structures.
                                                             (line    6)
* module; grp:                           grp — The group database.
                                                             (line    6)
* module; gzip:                          gzip — Support for gzip files.
                                                             (line    6)
* module; hashlib:                       hashlib — Secure hashes and message digests.
                                                             (line    6)
* module; heapq:                         heapq — Heap queue algorithm.
                                                             (line    6)
* module; hmac:                          hmac — Keyed-Hashing for Message Authentication.
                                                             (line    6)
* module; html:                          html — HyperText Markup Language support.
                                                             (line    6)
* module; html.entities:                 html entities — Definitions of HTML general entities.
                                                             (line    6)
* module; html.parser:                   html parser — Simple HTML and XHTML parser.
                                                             (line    6)
* module; http:                          http — HTTP modules.
                                                             (line    6)
* module; http.client:                   http client — HTTP protocol client.
                                                             (line    6)
* module; http.cookiejar:                http cookiejar — Cookie handling for HTTP clients.
                                                             (line    6)
* module; http.cookies:                  http cookies — HTTP state management.
                                                             (line    6)
* module; http.server:                   http server — HTTP servers.
                                                             (line    6)
* module; idlelib:                       idlelib — implementation of IDLE application.
                                                             (line    6)
* module; imaplib:                       imaplib — IMAP4 protocol client.
                                                             (line    6)
* module; imghdr:                        imghdr — Determine the type of an image.
                                                             (line    6)
* module; imp:                           imp — Access the import internals.
                                                             (line    6)
* module; importing:                     The import statement.
                                                             (line    6)
* module; importlib:                     importlib — The implementation of import.
                                                             (line    6)
* module; importlib.abc:                 importlib abc – Abstract base classes related to import.
                                                             (line    6)
* module; importlib.machinery:           importlib machinery – Importers and path hooks.
                                                             (line    6)
* module; importlib.metadata:            importlib metadata – Accessing package metadata.
                                                             (line    6)
* module; importlib.resources:           importlib resources – Package resource reading opening and access.
                                                             (line    6)
* module; importlib.resources.abc:       importlib resources abc – Abstract base classes for resources.
                                                             (line    6)
* module; importlib.util:                importlib util – Utility code for importers.
                                                             (line    6)
* module; inspect:                       inspect — Inspect live objects.
                                                             (line    6)
* module; io:                            I/O objects also known as file objects.
                                                             (line    6)
* module; io <1>:                        io — Core tools for working with streams.
                                                             (line    6)
* module; ipaddress:                     ipaddress — IPv4/IPv6 manipulation library.
                                                             (line    6)
* module; itertools:                     itertools — Functions creating iterators for efficient looping.
                                                             (line    6)
* module; json:                          Saving structured data with json.
                                                             (line    6)
* module; json <1>:                      json — JSON encoder and decoder.
                                                             (line    6)
* module; json.tool:                     Command Line Interface.
                                                             (line    6)
* module; keyword:                       keyword — Testing for Python keywords.
                                                             (line    6)
* module; linecache:                     linecache — Random access to text lines.
                                                             (line    6)
* module; locale:                        locale — Internationalization services.
                                                             (line    6)
* module; logging:                       logging — Logging facility for Python.
                                                             (line    6)
* module; logging.config:                logging config — Logging configuration.
                                                             (line    6)
* module; logging.handlers:              logging handlers — Logging handlers.
                                                             (line    6)
* module; lzma:                          lzma — Compression using the LZMA algorithm.
                                                             (line    6)
* module; mailbox:                       mailbox — Manipulate mailboxes in various formats.
                                                             (line    6)
* module; mailcap:                       mailcap — Mailcap file handling.
                                                             (line    6)
* module; marshal:                       marshal — Internal Python object serialization.
                                                             (line    6)
* module; math:                          Numeric Types — int float complex.
                                                             (line  106)
* module; math <1>:                      math — Mathematical functions.
                                                             (line    6)
* module; math <2>:                      Constants<3>.       (line   47)
* module; mimetypes:                     mimetypes — Map filenames to MIME types.
                                                             (line    6)
* module; mmap:                          mmap — Memory-mapped file support.
                                                             (line    6)
* module; modulefinder:                  modulefinder — Find modules used by a script.
                                                             (line    6)
* module; msilib:                        msilib — Read and write Microsoft Installer files.
                                                             (line    6)
* module; msvcrt:                        msvcrt — Useful routines from the MS VC++ runtime.
                                                             (line    6)
* module; multiprocessing:               multiprocessing — Process-based parallelism.
                                                             (line    6)
* module; multiprocessing.connection:    Listeners and Clients.
                                                             (line    6)
* module; multiprocessing.dummy:         The multiprocessing dummy module.
                                                             (line    6)
* module; multiprocessing.managers:      Managers.           (line   19)
* module; multiprocessing.pool:          Process Pools.      (line    6)
* module; multiprocessing.shared_memory: multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line    6)
* module; multiprocessing.sharedctypes:  The multiprocessing sharedctypes module.
                                                             (line    6)
* module; namespace:                     Modules<3>.         (line   21)
* module; netrc:                         netrc — netrc file processing.
                                                             (line    6)
* module; nis:                           nis — Interface to Sun’s NIS Yellow Pages.
                                                             (line    6)
* module; nntplib:                       nntplib — NNTP protocol client.
                                                             (line    6)
* module; numbers:                       numbers — Numeric abstract base classes.
                                                             (line    6)
* module; operator:                      operator — Standard operators as functions.
                                                             (line    6)
* module; optparse:                      optparse — Parser for command line options.
                                                             (line    6)
* module; os:                            os — Miscellaneous operating system interfaces.
                                                             (line    6)
* module; os <1>:                        posix — The most common POSIX system calls.
                                                             (line   14)
* module; os.path:                       os path — Common pathname manipulations.
                                                             (line    6)
* module; ossaudiodev:                   ossaudiodev — Access to OSS-compatible audio devices.
                                                             (line    6)
* module; pathlib:                       pathlib — Object-oriented filesystem paths.
                                                             (line    6)
* module; pdb:                           pdb — The Python Debugger.
                                                             (line    6)
* module; pickle:                        copy — Shallow and deep copy operations.
                                                             (line   75)
* module; pickle <1>:                    pickle — Python object serialization.
                                                             (line    6)
* module; pickle <2>:                    copyreg — Register pickle support functions.
                                                             (line    8)
* module; pickle <3>:                    shelve — Python object persistence.
                                                             (line    8)
* module; pickle <4>:                    marshal — Internal Python object serialization.
                                                             (line   15)
* module; pickletools:                   pickletools — Tools for pickle developers.
                                                             (line    6)
* module; pipes:                         pipes — Interface to shell pipelines.
                                                             (line    6)
* module; pkgutil:                       pkgutil — Package extension utility.
                                                             (line    6)
* module; platform:                      platform — Access to underlying platform’s identifying data.
                                                             (line    6)
* module; plistlib:                      plistlib — Generate and parse Apple plist files.
                                                             (line    6)
* module; poplib:                        poplib — POP3 protocol client.
                                                             (line    6)
* module; posix:                         posix — The most common POSIX system calls.
                                                             (line    6)
* module; pprint:                        pprint — Data pretty printer.
                                                             (line    6)
* module; profile:                       profile and cProfile Module Reference.
                                                             (line    6)
* module; pstats:                        The Stats Class.    (line    9)
* module; pty:                           File Descriptor Operations.
                                                             (line  480)
* module; pty <1>:                       pty — Pseudo-terminal utilities.
                                                             (line    6)
* module; pwd:                           os path — Common pathname manipulations.
                                                             (line  143)
* module; pwd <1>:                       pwd — The password database.
                                                             (line    6)
* module; py_compile:                    py_compile — Compile Python source files.
                                                             (line    6)
* module; pyclbr:                        pyclbr — Python module browser support.
                                                             (line    6)
* module; pydoc:                         pydoc — Documentation generator and online help system.
                                                             (line    6)
* module; pyexpat:                       xml parsers expat — Fast XML parsing using Expat.
                                                             (line   19)
* module; queue:                         queue — A synchronized queue class.
                                                             (line    6)
* module; quopri:                        quopri — Encode and decode MIME quoted-printable data.
                                                             (line    6)
* module; random:                        random — Generate pseudo-random numbers.
                                                             (line    6)
* module; re:                            String Methods<2>.  (line    6)
* module; re <1>:                        re — Regular expression operations.
                                                             (line    6)
* module; re <2>:                        fnmatch — Unix filename pattern matching.
                                                             (line    8)
* module; readline:                      readline — GNU readline interface.
                                                             (line    6)
* module; reprlib:                       reprlib — Alternate repr implementation.
                                                             (line    6)
* module; resource:                      resource — Resource usage information.
                                                             (line    6)
* module; rlcompleter:                   rlcompleter — Completion function for GNU readline.
                                                             (line    6)
* module; runpy:                         runpy — Locating and executing Python modules.
                                                             (line    6)
* module; sched:                         sched — Event scheduler.
                                                             (line    6)
* module; search; path:                  The Module Search Path.
                                                             (line    6)
* module; search; path <1>:              linecache — Random access to text lines.
                                                             (line   30)
* module; search; path <2>:              sys — System-specific parameters and functions.
                                                             (line 1329)
* module; search; path <3>:              site — Site-specific configuration hook.
                                                             (line   14)
* module; search; path <4>:              Embedding Python<2>.
                                                             (line   12)
* module; search; path <5>:              Initializing and finalizing the interpreter.
                                                             (line    7)
* module; search; path <6>:              Process-wide parameters.
                                                             (line  136)
* module; secrets:                       secrets — Generate secure random numbers for managing secrets.
                                                             (line    6)
* module; select:                        select — Waiting for I/O completion.
                                                             (line    6)
* module; selectors:                     selectors — High-level I/O multiplexing.
                                                             (line    6)
* module; shelve:                        shelve — Python object persistence.
                                                             (line    6)
* module; shelve <1>:                    marshal — Internal Python object serialization.
                                                             (line   15)
* module; shlex:                         shlex — Simple lexical analysis.
                                                             (line    6)
* module; shutil:                        shutil — High-level file operations.
                                                             (line    6)
* module; signal:                        _thread — Low-level threading API.
                                                             (line  192)
* module; signal <1>:                    signal — Set handlers for asynchronous events.
                                                             (line    6)
* module; signal <2>:                    Signal Handling<2>. (line    7)
* module; signal <3>:                    Signal Handling<2>. (line   46)
* module; signal <4>:                    Signal Handling<2>. (line   55)
* module; site:                          site — Site-specific configuration hook.
                                                             (line    6)
* module; sitecustomize:                 sitecustomize.      (line    6)
* module; smtpd:                         smtpd — SMTP Server.
                                                             (line    6)
* module; smtplib:                       smtplib — SMTP protocol client.
                                                             (line    6)
* module; sndhdr:                        sndhdr — Determine type of sound file.
                                                             (line    6)
* module; socket:                        socket — Low-level networking interface.
                                                             (line    6)
* module; socket <1>:                    Internet Protocols and Support.
                                                             (line    6)
* module; socketserver:                  socketserver — A framework for network servers.
                                                             (line    6)
* module; spwd:                          spwd — The shadow password database.
                                                             (line    6)
* module; sqlite3:                       sqlite3 — DB-API 2 0 interface for SQLite databases.
                                                             (line    6)
* module; ssl:                           ssl — TLS/SSL wrapper for socket objects.
                                                             (line    6)
* module; stat:                          stat — Interpreting stat results.
                                                             (line    6)
* module; stat <1>:                      Files and Directories.
                                                             (line 1109)
* module; statistics:                    statistics — Mathematical statistics functions.
                                                             (line    6)
* module; string:                        string — Common string operations.
                                                             (line    6)
* module; stringprep:                    stringprep — Internet String Preparation.
                                                             (line    6)
* module; struct:                        struct — Interpret bytes as packed binary data.
                                                             (line    6)
* module; struct <1>:                    Socket Objects.     (line  563)
* module; subprocess:                    subprocess — Subprocess management.
                                                             (line    6)
* module; sunau:                         sunau — Read and write Sun AU files.
                                                             (line    6)
* module; symtable:                      symtable — Access to the compiler’s symbol tables.
                                                             (line    6)
* module; sys:                           Standard Modules.   (line    6)
* module; sys <1>:                       except clause.      (line   59)
* module; sys <2>:                       Complete Python programs.
                                                             (line    6)
* module; sys <3>:                       Built-in Functions. (line 1464)
* module; sys <4>:                       sys — System-specific parameters and functions.
                                                             (line    6)
* module; sys <5>:                       Embedding Python<2>.
                                                             (line   12)
* module; sys <6>:                       Initializing and finalizing the interpreter.
                                                             (line    7)
* module; sys <7>:                       Sub-interpreter support.
                                                             (line  112)
* module; sys <8>:                       Sub-interpreter support.
                                                             (line  197)
* module; sys.monitoring:                sys monitoring — Execution event monitoring.
                                                             (line    6)
* module; sysconfig:                     sysconfig — Provide access to Python’s configuration information.
                                                             (line    6)
* module; syslog:                        syslog — Unix syslog library routines.
                                                             (line    6)
* module; tabnanny:                      tabnanny — Detection of ambiguous indentation.
                                                             (line    6)
* module; tarfile:                       tarfile — Read and write tar archive files.
                                                             (line    6)
* module; telnetlib:                     telnetlib — Telnet client.
                                                             (line    6)
* module; tempfile:                      tempfile — Generate temporary files and directories.
                                                             (line    6)
* module; termios:                       termios — POSIX style tty control.
                                                             (line    6)
* module; test:                          test — Regression tests package for Python.
                                                             (line    6)
* module; test.regrtest:                 Running tests using the command-line interface.
                                                             (line    6)
* module; test.support:                  test support — Utilities for the Python test suite.
                                                             (line    6)
* module; test.support.bytecode_helper:  test support bytecode_helper — Support tools for testing correct bytecode generation.
                                                             (line    6)
* module; test.support.import_helper:    test support import_helper — Utilities for import tests.
                                                             (line    6)
* module; test.support.os_helper:        test support os_helper — Utilities for os tests.
                                                             (line    6)
* module; test.support.script_helper:    test support script_helper — Utilities for the Python execution tests.
                                                             (line    6)
* module; test.support.socket_helper:    test support socket_helper — Utilities for socket tests.
                                                             (line    6)
* module; test.support.threading_helper: test support threading_helper — Utilities for threading tests.
                                                             (line    6)
* module; test.support.warnings_helper:  test support warnings_helper — Utilities for warnings tests.
                                                             (line    6)
* module; textwrap:                      textwrap — Text wrapping and filling.
                                                             (line    6)
* module; threading:                     threading — Thread-based parallelism.
                                                             (line    6)
* module; time:                          time — Time access and conversions.
                                                             (line    6)
* module; timeit:                        timeit — Measure execution time of small code snippets.
                                                             (line    6)
* module; tkinter:                       tkinter — Python interface to Tcl/Tk.
                                                             (line    6)
* module; tkinter.colorchooser:          tkinter colorchooser — Color choosing dialog.
                                                             (line    6)
* module; tkinter.commondialog:          tkinter commondialog — Dialog window templates.
                                                             (line    6)
* module; tkinter.dnd:                   tkinter dnd — Drag and drop support.
                                                             (line    6)
* module; tkinter.filedialog:            tkinter filedialog — File selection dialogs.
                                                             (line    6)
* module; tkinter.font:                  tkinter font — Tkinter font wrapper.
                                                             (line    6)
* module; tkinter.messagebox:            tkinter messagebox — Tkinter message prompts.
                                                             (line    6)
* module; tkinter.scrolledtext:          tkinter scrolledtext — Scrolled Text Widget.
                                                             (line    6)
* module; tkinter.simpledialog:          tkinter simpledialog — Standard Tkinter input dialogs.
                                                             (line    6)
* module; tkinter.ttk:                   tkinter ttk — Tk themed widgets.
                                                             (line    6)
* module; token:                         token — Constants used with Python parse trees.
                                                             (line    6)
* module; tokenize:                      tokenize — Tokenizer for Python source.
                                                             (line    6)
* module; tomllib:                       tomllib — Parse TOML files.
                                                             (line    6)
* module; trace:                         trace — Trace or track Python statement execution.
                                                             (line    6)
* module; traceback:                     traceback — Print or retrieve a stack traceback.
                                                             (line    6)
* module; tracemalloc:                   tracemalloc — Trace memory allocations.
                                                             (line    6)
* module; tty:                           tty — Terminal control functions.
                                                             (line    6)
* module; turtle:                        turtle — Turtle graphics.
                                                             (line    6)
* module; turtledemo:                    turtledemo — Demo scripts.
                                                             (line    6)
* module; types:                         Type Objects.       (line    6)
* module; types <1>:                     types — Dynamic type creation and names for built-in types.
                                                             (line    6)
* module; typing:                        typing — Support for type hints.
                                                             (line    6)
* module; unicodedata:                   unicodedata — Unicode Database.
                                                             (line    6)
* module; unittest:                      unittest — Unit testing framework.
                                                             (line    6)
* module; unittest.mock:                 unittest mock — mock object library.
                                                             (line    6)
* module; urllib:                        urllib — URL handling modules.
                                                             (line    6)
* module; urllib.error:                  urllib error — Exception classes raised by urllib request.
                                                             (line    6)
* module; urllib.parse:                  urllib parse — Parse URLs into components.
                                                             (line    6)
* module; urllib.request:                urllib request — Extensible library for opening URLs.
                                                             (line    6)
* module; urllib.request <1>:            http client — HTTP protocol client.
                                                             (line    8)
* module; urllib.response:               urllib response — Response classes used by urllib.
                                                             (line    6)
* module; urllib.robotparser:            urllib robotparser — Parser for robots txt.
                                                             (line    6)
* module; usercustomize:                 usercustomize.      (line    6)
* module; uu:                            uu — Encode and decode uuencode files.
                                                             (line    6)
* module; uuid:                          uuid — UUID objects according to RFC 4122.
                                                             (line    8)
* module; venv:                          venv — Creation of virtual environments.
                                                             (line    6)
* module; warnings:                      warnings — Warning control.
                                                             (line    6)
* module; wave:                          wave — Read and write WAV files.
                                                             (line    6)
* module; weakref:                       weakref — Weak references.
                                                             (line    6)
* module; webbrowser:                    webbrowser — Convenient web-browser controller.
                                                             (line    6)
* module; winreg:                        winreg — Windows registry access.
                                                             (line    6)
* module; winsound:                      winsound — Sound-playing interface for Windows.
                                                             (line    6)
* module; wsgiref:                       wsgiref — WSGI Utilities and Reference Implementation.
                                                             (line    6)
* module; wsgiref.handlers:              wsgiref handlers – server/gateway base classes.
                                                             (line    6)
* module; wsgiref.headers:               wsgiref headers – WSGI response header tools.
                                                             (line    6)
* module; wsgiref.simple_server:         wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line    6)
* module; wsgiref.types:                 wsgiref types – WSGI types for static type checking.
                                                             (line    6)
* module; wsgiref.util:                  wsgiref util – WSGI environment utilities.
                                                             (line    6)
* module; wsgiref.validate:              wsgiref validate — WSGI conformance checker.
                                                             (line    6)
* module; xdrlib:                        xdrlib — Encode and decode XDR data.
                                                             (line    6)
* module; xml:                           XML Processing Modules.
                                                             (line    6)
* module; xml.dom:                       xml dom — The Document Object Model API.
                                                             (line    6)
* module; xml.dom.minidom:               xml dom minidom — Minimal DOM implementation.
                                                             (line    6)
* module; xml.dom.pulldom:               xml dom pulldom — Support for building partial DOM trees.
                                                             (line    6)
* module; xml.etree.ElementInclude:      Functions<10>.      (line    6)
* module; xml.etree.ElementTree:         xml etree ElementTree — The ElementTree XML API.
                                                             (line    6)
* module; xml.parsers.expat:             xml parsers expat — Fast XML parsing using Expat.
                                                             (line    6)
* module; xml.parsers.expat.errors:      Expat error constants.
                                                             (line    6)
* module; xml.parsers.expat.model:       Content Model Descriptions.
                                                             (line    6)
* module; xml.sax:                       xml sax — Support for SAX2 parsers.
                                                             (line    6)
* module; xml.sax.handler:               xml sax handler — Base classes for SAX handlers.
                                                             (line    6)
* module; xml.sax.saxutils:              xml sax saxutils — SAX Utilities.
                                                             (line    6)
* module; xml.sax.xmlreader:             xml sax xmlreader — Interface for XML parsers.
                                                             (line    6)
* module; xmlrpc:                        xmlrpc — XMLRPC server and client modules.
                                                             (line    6)
* module; xmlrpc.client:                 xmlrpc client — XML-RPC client access.
                                                             (line    6)
* module; xmlrpc.server:                 xmlrpc server — Basic XML-RPC servers.
                                                             (line    6)
* module; zipapp:                        zipapp — Manage executable Python zip archives.
                                                             (line    6)
* module; zipfile:                       zipfile — Work with ZIP archives.
                                                             (line    6)
* module; zipimport:                     zipimport — Import modules from Zip archives.
                                                             (line    6)
* module; zlib:                          zlib — Compression compatible with gzip.
                                                             (line    6)
* module; zoneinfo:                      zoneinfo — IANA time zone support.
                                                             (line    6)
* ModuleFinder (class in modulefinder):  modulefinder — Find modules used by a script.
                                                             (line   26)
* ModuleInfo (class in pkgutil):         pkgutil — Package extension utility.
                                                             (line   13)
* ModuleNotFoundError:                   Concrete exceptions.
                                                             (line   72)
* modules (in module sys):               sys — System-specific parameters and functions.
                                                             (line 1302)
* modules (in module sys) <1>:           Importing Modules<2>.
                                                             (line    9)
* modules (in module sys) <2>:           Initializing and finalizing the interpreter.
                                                             (line    7)
* modules (modulefinder.ModuleFinder attribute): modulefinder — Find modules used by a script.
                                                             (line   49)
* modules_cleanup() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   71)
* modules_setup() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   67)
* ModuleSpec (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  364)
* ModuleType (class in types):           Standard Interpreter Types.
                                                             (line  123)
* ModuleType (in module types):          Module Objects.     (line    7)
* modulo:                                Binary arithmetic operations.
                                                             (line   46)
* modulus (sys.hash_info attribute):     sys — System-specific parameters and functions.
                                                             (line 1037)
* MON_1 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_10 (in module locale):             locale — Internationalization services.
                                                             (line  249)
* MON_11 (in module locale):             locale — Internationalization services.
                                                             (line  249)
* MON_12 (in module locale):             locale — Internationalization services.
                                                             (line  249)
* MON_2 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_3 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_4 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_5 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_6 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_7 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_8 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MON_9 (in module locale):              locale — Internationalization services.
                                                             (line  249)
* MONDAY (in module calendar):           calendar — General calendar-related functions.
                                                             (line  445)
* monotonic_ns() (in module time):       Functions<5>.       (line  208)
* monotonic() (in module time):          Functions<5>.       (line  175)
* month (calendar.IllegalMonthError attribute): calendar — General calendar-related functions.
                                                             (line  521)
* Month (class in calendar):             calendar — General calendar-related functions.
                                                             (line  506)
* month (datetime.date attribute):       date Objects.       (line  120)
* month (datetime.datetime attribute):   datetime Objects.   (line  308)
* month_abbr (in module calendar):       calendar — General calendar-related functions.
                                                             (line  477)
* month_name (in module calendar):       calendar — General calendar-related functions.
                                                             (line  466)
* month() (in module calendar):          calendar — General calendar-related functions.
                                                             (line  401)
* monthcalendar() (in module calendar):  calendar — General calendar-related functions.
                                                             (line  390)
* monthdatescalendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  110)
* monthdays2calendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  116)
* monthdayscalendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  122)
* monthrange() (in module calendar):     calendar — General calendar-related functions.
                                                             (line  385)
* Morsel (class in http.cookies):        Morsel Objects.     (line    6)
* most_common() (collections.Counter method): Counter objects.
                                                             (line   82)
* mouseinterval() (in module curses):    Functions<6>.       (line  291)
* mousemask() (in module curses):        Functions<6>.       (line  298)
* move_to_end() (collections.OrderedDict method): OrderedDict objects.
                                                             (line   78)
* move() (curses.panel.Panel method):    Panel Objects.      (line   35)
* move() (curses.window method):         Window Objects.     (line  397)
* move() (in module shutil):             Directory and files operations.
                                                             (line  338)
* move() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  237)
* move() (tkinter.ttk.Treeview method):  ttk Treeview.       (line  211)
* MozillaCookieJar (class in http.cookiejar): FileCookieJar subclasses and co-operation with web browsers.
                                                             (line    9)
* MRO:                                   Glossary.           (line 1104)
* mro() (type method):                   Special methods.    (line    9)
* msg (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   40)
* msg (json.JSONDecodeError attribute):  Exceptions<17>.     (line   11)
* msg (netrc.NetrcParseError attribute): netrc — netrc file processing.
                                                             (line   52)
* msg (re.PatternError attribute):       Exceptions<3>.      (line   15)
* msg (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line  122)
* mtime (gzip.GzipFile attribute):       gzip — Support for gzip files.
                                                             (line  148)
* mtime (tarfile.TarInfo attribute):     TarInfo Objects.    (line   69)
* mtime() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   39)
* mul() (in module operator):            operator — Standard operators as functions.
                                                             (line  120)
* Mult (class in ast):                   Expressions<2>.     (line   53)
* MultiCall (class in xmlrpc.client):    MultiCall Objects.  (line    9)
* MULTILINE (in module re):              Flags.              (line   82)
* MultilineContinuationError:            Exceptions<8>.      (line   73)
* MultiLoopChildWatcher (class in asyncio): Process Watchers.
                                                             (line  106)
* multimode() (in module statistics):    Function details.   (line  357)
* MultipartConversionError:              email errors Exception and Defect classes.
                                                             (line   42)
* MultipartInvariantViolationDefect:     email errors Exception and Defect classes.
                                                             (line  116)
* multiplication:                        Binary arithmetic operations.
                                                             (line   16)
* multiply() (decimal.Context method):   Context objects.    (line  419)
* mutable:                               Glossary.           (line 1108)
* mutable object:                        Objects values and types.
                                                             (line   10)
* mutable sequence; loop over:           Common Sequence Operations.
                                                             (line   66)
* mutable; sequence; types:              Mutable Sequence Types.
                                                             (line    6)
* MutableMapping (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  119)
* MutableMapping (class in typing):      Aliases to container ABCs in collections abc.
                                                             (line   88)
* MutableSequence (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   67)
* MutableSequence (class in typing):     Aliases to container ABCs in collections abc.
                                                             (line   96)
* MutableSet (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  114)
* MutableSet (class in typing):          Aliases to container ABCs in collections abc.
                                                             (line  104)
* mvderwin() (curses.window method):     Window Objects.     (line  401)
* mvwin() (curses.window method):        Window Objects.     (line  408)
* myrights() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  160)
* N_TOKENS (in module token):            token — Constants used with Python parse trees.
                                                             (line  322)
* n_waiting (asyncio.Barrier attribute): Barrier.            (line   97)
* n_waiting (threading.Barrier attribute): Barrier objects.  (line   96)
* NAK (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   87)
* name:                                  Identifiers and keywords.
                                                             (line    6)
* name <1>:                              Binding of names.   (line    6)
* name <2>:                              Identifiers Names.  (line    6)
* name (AttributeError attribute):       Concrete exceptions.
                                                             (line   22)
* name (bz2.BZ2File attribute):          De compression of files.
                                                             (line  134)
* Name (class in ast):                   Variables.          (line    6)
* name (codecs.CodecInfo attribute):     codecs — Codec registry and base classes.
                                                             (line   74)
* name (contextvars.ContextVar attribute): Context Variables.
                                                             (line   24)
* name (doctest.DocTest attribute):      DocTest Objects.    (line   29)
* name (email.headerregistry.BaseHeader attribute): email headerregistry Custom Header Objects.
                                                             (line   45)
* name (enum.Enum attribute):            Data types.         (line  124)
* name (gzip.GzipFile attribute):        gzip — Support for gzip files.
                                                             (line  156)
* name (hashlib.hash attribute):         Hash Objects.       (line   19)
* name (hmac.HMAC attribute):            hmac — Keyed-Hashing for Message Authentication.
                                                             (line  104)
* name (http.cookiejar.Cookie attribute): Cookie Objects<2>. (line   27)
* name (ImportError attribute):          Concrete exceptions.
                                                             (line   61)
* name (importlib.abc.FileLoader attribute): importlib abc – Abstract base classes related to import.
                                                             (line  302)
* name (importlib.abc.Traversable attribute): importlib abc – Abstract base classes related to import.
                                                             (line  519)
* name (importlib.machinery.AppleFrameworkLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  500)
* name (importlib.machinery.ExtensionFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  306)
* name (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  380)
* name (importlib.machinery.SourceFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  212)
* name (importlib.machinery.SourcelessFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  256)
* name (importlib.resources.abc.Traversable attribute): importlib resources abc – Abstract base classes for resources.
                                                             (line   97)
* name (in module os):                   os — Miscellaneous operating system interfaces.
                                                             (line   55)
* NAME (in module token):                token — Constants used with Python parse trees.
                                                             (line   45)
* name (inspect.Parameter attribute):    Introspecting callables with the Signature object.
                                                             (line  203)
* name (io.FileIO attribute):            Raw File I/O.       (line   59)
* name (logging.Logger attribute):       Logger Objects.     (line   26)
* name (lzma.LZMAFile attribute):        Reading and writing compressed files.
                                                             (line  104)
* name (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  115)
* name (multiprocessing.shared_memory.SharedMemory attribute): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  120)
* name (NameError attribute):            Concrete exceptions.
                                                             (line  126)
* name (os.DirEntry attribute):          Files and Directories.
                                                             (line  937)
* name (pathlib.PurePath attribute):     Methods and properties.
                                                             (line  122)
* name (pyclbr.Class attribute):         Class Objects<2>.   (line   20)
* name (pyclbr.Function attribute):      Function Objects.   (line   19)
* name (sys.thread_info attribute):      sys — System-specific parameters and functions.
                                                             (line 1921)
* name (tarfile.TarInfo attribute):      TarInfo Objects.    (line   61)
* name (tempfile.TemporaryDirectory attribute): tempfile — Generate temporary files and directories.
                                                             (line  194)
* name (threading.Thread attribute):     Thread objects.     (line  151)
* name (traceback.FrameSummary attribute): FrameSummary Objects.
                                                             (line   38)
* name (webbrowser.controller attribute): Browser controller objects.
                                                             (line   10)
* name (xml.dom.Attr attribute):         Attr Objects.       (line    8)
* name (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   33)
* name (zipfile.Path attribute):         Path objects.       (line   31)
* name; binding:                         The import statement.
                                                             (line    6)
* name; binding <1>:                     The import statement.
                                                             (line   52)
* name; binding <2>:                     Function definitions.
                                                             (line    6)
* name; binding <3>:                     Function definitions.
                                                             (line    6)
* name; binding <4>:                     Class definitions.  (line    6)
* name; mangling:                        Private Variables.  (line   13)
* name; mangling <1>:                    Identifiers Names.  (line   14)
* name() (in module unicodedata):        unicodedata — Unicode Database.
                                                             (line   40)
* name2codepoint (in module html.entities): html entities — Definitions of HTML general entities.
                                                             (line   30)
* named expression:                      Boolean operations. (line   38)
* Named Shared Memory:                   multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line   10)
* named tuple:                           Glossary.           (line 1117)
* NAMED_FLAGS (enum.EnumCheck attribute): Data types.        (line  687)
* NamedExpr (class in ast):              Expressions<2>.     (line  184)
* NamedTemporaryFile() (in module tempfile): tempfile — Generate temporary files and directories.
                                                             (line   74)
* NamedTuple (class in typing):          Other special directives.
                                                             (line   10)
* namedtuple() (in module collections):  namedtuple Factory Function for Tuples with Named Fields.
                                                             (line   11)
* NameError:                             Concrete exceptions.
                                                             (line  118)
* NameError (built-in exception):        Resolution of names.
                                                             (line   16)
* namelist() (zipfile.ZipFile method):   ZipFile objects.    (line  125)
* nameprep() (in module encodings.idna): encodings idna — Internationalized Domain Names in Applications.
                                                             (line   49)
* namer (logging.handlers.BaseRotatingHandler attribute): BaseRotatingHandler.
                                                             (line   17)
* namereplace_errors() (in module codecs): Error Handlers.   (line  181)
* namereplace; error handler's name:     Error Handlers.     (line   54)
* names() (in module tkinter.font):      tkinter font — Tkinter font wrapper.
                                                             (line   92)
* namespace:                             Naming and binding. (line    6)
* namespace <1>:                         Glossary.           (line 1144)
* Namespace (class in argparse):         The Namespace object.
                                                             (line    6)
* Namespace (class in multiprocessing.managers): Managers.   (line  243)
* namespace package:                     Glossary.           (line 1158)
* NAMESPACE_DNS (in module uuid):        uuid — UUID objects according to RFC 4122.
                                                             (line  206)
* NAMESPACE_OID (in module uuid):        uuid — UUID objects according to RFC 4122.
                                                             (line  215)
* NAMESPACE_URL (in module uuid):        uuid — UUID objects according to RFC 4122.
                                                             (line  211)
* NAMESPACE_X500 (in module uuid):       uuid — UUID objects according to RFC 4122.
                                                             (line  219)
* namespace() (imaplib.IMAP4 method):    IMAP4 Objects.      (line  165)
* Namespace() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  193)
* NamespaceErr:                          Exceptions<20>.     (line   66)
* NamespaceLoader (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  347)
* namespaceURI (xml.dom.Node attribute): Node Objects.       (line   74)
* nametofont() (in module tkinter.font): tkinter font — Tkinter font wrapper.
                                                             (line   96)
* NaN:                                   Built-in Functions. (line  724)
* nan (in module cmath):                 Constants<3>.       (line   33)
* nan (in module math):                  Constants<2>.       (line   31)
* nan (sys.hash_info attribute):         sys — System-specific parameters and functions.
                                                             (line 1045)
* nanj (in module cmath):                Constants<3>.       (line   40)
* NannyNag:                              tabnanny — Detection of ambiguous indentation.
                                                             (line   37)
* napms() (in module curses):            Functions<6>.       (line  307)
* nargs (optparse.Option attribute):     Option attributes.  (line   50)
* native code:                           Glossary.           (line 1174)
* native_id (threading.Thread attribute): Thread objects.    (line  173)
* nbytes (memoryview attribute):         Memory Views.       (line  383)
* ncurses_version (in module curses):    Constants<6>.       (line   22)
* ND (inspect.BufferFlags attribute):    Buffer flags.       (line   21)
* ndiff() (in module difflib):           difflib — Helpers for computing deltas.
                                                             (line  232)
* ndim (memoryview attribute):           Memory Views.       (line  449)
* ne() (in module operator):             operator — Standard operators as functions.
                                                             (line   24)
* needs_input (bz2.BZ2Decompressor attribute): Incremental de compression.
                                                             (line   85)
* needs_input (lzma.LZMADecompressor attribute): Compressing and decompressing data in memory.
                                                             (line  173)
* neg() (in module operator):            operator — Standard operators as functions.
                                                             (line  132)
* negation:                              Unary arithmetic and bitwise operations.
                                                             (line   10)
* nested scope:                          Glossary.           (line 1182)
* nested_scopes (in module __future__):  Module Contents<4>. (line   14)
* netmask (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  101)
* netmask (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  315)
* NetmaskValueError:                     Custom Exceptions.  (line   13)
* netrc (class in netrc):                netrc — netrc file processing.
                                                             (line   13)
* NetrcParseError:                       netrc — netrc file processing.
                                                             (line   46)
* netscape (http.cookiejar.CookiePolicy attribute): CookiePolicy Objects.
                                                             (line   67)
* network (ipaddress.IPv4Interface attribute): Interface objects.
                                                             (line   28)
* network (ipaddress.IPv6Interface attribute): Interface objects.
                                                             (line   76)
* network_address (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   86)
* network_address (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  309)
* Never (in module typing):              Special types.      (line   99)
* NEVER_EQ (in module test.support):     test support — Utilities for the Python test suite.
                                                             (line  179)
* new_child() (collections.ChainMap method): ChainMap objects.
                                                             (line   46)
* new_class() (in module types):         Dynamic Type Creation.
                                                             (line    6)
* new_event_loop() (asyncio.AbstractEventLoopPolicy method): Policy Objects.
                                                             (line   27)
* new_event_loop() (in module asyncio):  Event loop.         (line   67)
* new_panel() (in module curses.panel):  Functions<7>.       (line   12)
* new-style class:                       Glossary.           (line 1192)
* new() (in module hashlib):             Constructors.       (line    6)
* new() (in module hmac):                hmac — Keyed-Hashing for Message Authentication.
                                                             (line   15)
* newfunc (C type):                      Slot Type typedefs. (line   31)
* NEWLINE (in module token):             token — Constants used with Python parse trees.
                                                             (line   76)
* NEWLINE token:                         Logical lines.      (line    6)
* NEWLINE token <1>:                     Compound statements.
                                                             (line   55)
* newlines (io.TextIOBase attribute):    Text I/O<2>.        (line   24)
* newpad() (in module curses):           Functions<6>.       (line  311)
* NewType (class in typing):             Other special directives.
                                                             (line  105)
* newwin() (in module curses):           Functions<6>.       (line  331)
* next (pdb command):                    Debugger commands.  (line  202)
* next_minus() (decimal.Context method): Context objects.    (line  423)
* next_minus() (decimal.Decimal method): Decimal objects.    (line  396)
* next_plus() (decimal.Context method):  Context objects.    (line  427)
* next_plus() (decimal.Decimal method):  Decimal objects.    (line  402)
* next_toward() (decimal.Context method): Context objects.   (line  431)
* next_toward() (decimal.Decimal method): Decimal objects.   (line  408)
* next() (tarfile.TarFile method):       TarFile Objects.    (line  131)
* next() (tkinter.ttk.Treeview method):  ttk Treeview.       (line  222)
* nextafter() (in module math):          Floating point manipulation functions.
                                                             (line   82)
* nextfile() (in module fileinput):      fileinput — Iterate over lines from multiple input streams.
                                                             (line  121)
* nextkey() (dbm.gnu.gdbm method):       dbm gnu — GNU database manager.
                                                             (line  108)
* nextSibling (xml.dom.Node attribute):  Node Objects.       (line   42)
* ngettext() (gettext.GNUTranslations method): The GNUTranslations class.
                                                             (line   47)
* ngettext() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   41)
* ngettext() (in module gettext):        GNU gettext API.    (line   44)
* nice() (in module os):                 Process Management. (line  354)
* NL (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   54)
* NL (in module token):                  token — Constants used with Python parse trees.
                                                             (line   80)
* nl_langinfo() (in module locale):      locale — Internationalization services.
                                                             (line  185)
* nl() (in module curses):               Functions<6>.       (line  341)
* nlargest() (in module heapq):          heapq — Heap queue algorithm.
                                                             (line  109)
* nlst() (ftplib.FTP method):            FTP objects.        (line  300)
* NO (in module tkinter.messagebox):     tkinter messagebox — Tkinter message prompts.
                                                             (line  159)
* no_cache() (zoneinfo.ZoneInfo class method): The ZoneInfo class.
                                                             (line   44)
* NO_EVENTS (monitoring event):          Events.             (line   94)
* no_proxy:                              urllib request — Extensible library for opening URLs.
                                                             (line  309)
* no_site (sys.flags attribute):         sys — System-specific parameters and functions.
                                                             (line  548)
* no_tracing() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  542)
* no_type_check_decorator() (in module typing): Functions and decorators.
                                                             (line  360)
* no_type_check() (in module typing):    Functions and decorators.
                                                             (line  348)
* no_user_site (sys.flags attribute):    sys — System-specific parameters and functions.
                                                             (line  545)
* NoBoundaryInMultipartDefect:           email errors Exception and Defect classes.
                                                             (line   75)
* nocbreak() (in module curses):         Functions<6>.       (line  347)
* NoDataAllowedErr:                      Exceptions<20>.     (line   83)
* node (uuid.UUID attribute):            uuid — UUID objects according to RFC 4122.
                                                             (line  119)
* node() (in module platform):           Cross platform.     (line   43)
* NoDefault (in module typing):          Introspection helpers.
                                                             (line  165)
* nodelay() (curses.window method):      Window Objects.     (line  412)
* nodeName (xml.dom.Node attribute):     Node Objects.       (line   79)
* NodeTransformer (class in ast):        ast Helpers.        (line  224)
* nodeType (xml.dom.Node attribute):     Node Objects.       (line    8)
* nodeValue (xml.dom.Node attribute):    Node Objects.       (line   88)
* NodeVisitor (class in ast):            ast Helpers.        (line  184)
* noecho() (in module curses):           Functions<6>.       (line  352)
* NOEXPR (in module locale):             locale — Internationalization services.
                                                             (line  294)
* NOFLAG (in module re):                 Flags.              (line   96)
* NoModificationAllowedErr:              Exceptions<20>.     (line   88)
* non-deterministic:                     Glossary.           (line 1200)
* NonCallableMagicMock (class in unittest.mock): Magic Mock. (line   22)
* NonCallableMock (class in unittest.mock): The Mock Class.  (line  579)
* None (Built-in object):                Truth Value Testing.
                                                             (line   15)
* None (built-in variable):              Built-in Constants. (line   18)
* NoneType (in module types):            Standard Interpreter Types.
                                                             (line   19)
* nonl() (in module curses):             Functions<6>.       (line  356)
* Nonlocal (class in ast):               Function and class definitions.
                                                             (line  145)
* nonmember() (in module enum):          Utilities and decorators.
                                                             (line   86)
* noop() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  169)
* noop() (poplib.POP3 method):           POP3 Objects.       (line   79)
* NoOptionError:                         Exceptions<8>.      (line   32)
* NOP (opcode):                          Python Bytecode Instructions.
                                                             (line  134)
* noqiflush() (in module curses):        Functions<6>.       (line  366)
* noraw() (in module curses):            Functions<6>.       (line  374)
* NoReturn (in module typing):           Special types.      (line   99)
* NORMAL (in module tkinter.font):       tkinter font — Tkinter font wrapper.
                                                             (line   15)
* NORMAL_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line   96)
* NormalDist (class in statistics):      NormalDist objects. (line   13)
* normalize_encoding() (in module encodings): encodings — Encodings package.
                                                             (line    8)
* NORMALIZE_WHITESPACE (in module doctest): Option Flags.    (line   37)
* normalize() (decimal.Context method):  Context objects.    (line  435)
* normalize() (decimal.Decimal method):  Decimal objects.    (line  416)
* normalize() (in module locale):        locale — Internationalization services.
                                                             (line  435)
* normalize() (in module unicodedata):   unicodedata — Unicode Database.
                                                             (line  133)
* normalize() (xml.dom.Node method):     Node Objects.       (line  141)
* normalvariate() (in module random):    Real-valued distributions.
                                                             (line   85)
* normcase() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  352)
* normpath() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  361)
* NoSectionError:                        Exceptions<8>.      (line   10)
* NoSuchMailboxError:                    Exceptions<18>.     (line   12)
* Not (class in ast):                    Expressions<2>.     (line   27)
* not_() (in module operator):           operator — Standard operators as functions.
                                                             (line   49)
* NotADirectoryError:                    OS exceptions.      (line   89)
* notation:                              Notation.           (line    6)
* notationDecl() (xml.sax.handler.DTDHandler method): DTDHandler Objects.
                                                             (line    8)
* NotationDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  362)
* notations (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   46)
* NotConnected:                          http client — HTTP protocol client.
                                                             (line  136)
* Notebook (class in tkinter.ttk):       ttk Notebook.       (line    6)
* NotEmptyError:                         Exceptions<18>.     (line   19)
* NotEq (class in ast):                  Expressions<2>.     (line  108)
* NOTEQUAL (in module token):            token — Constants used with Python parse trees.
                                                             (line  239)
* NotFoundErr:                           Exceptions<20>.     (line   72)
* notify_all() (asyncio.Condition method): Condition.        (line   67)
* notify_all() (threading.Condition method): Condition objects.
                                                             (line  171)
* notify() (asyncio.Condition method):   Condition.          (line   54)
* notify() (threading.Condition method): Condition objects.  (line  152)
* notimeout() (curses.window method):    Window Objects.     (line  416)
* NotImplemented (built-in variable):    Built-in Constants. (line   25)
* NotImplementedError:                   Concrete exceptions.
                                                             (line  132)
* NotImplementedType (in module types):  Standard Interpreter Types.
                                                             (line  103)
* NotIn (class in ast):                  Expressions<2>.     (line  108)
* NotRequired (in module typing):        Special forms.      (line  259)
* NOTSET (in module logging):            Logging Levels.     (line   16)
* NotStandaloneHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  413)
* NotSupportedErr:                       Exceptions<20>.     (line   78)
* NotSupportedError:                     Exceptions<7>.      (line   85)
* noutrefresh() (curses.window method):  Window Objects.     (line  424)
* NOVEMBER (in module calendar):         calendar — General calendar-related functions.
                                                             (line  488)
* now() (datetime.datetime class method): datetime Objects.  (line   61)
* npgettext() (gettext.GNUTranslations method): The GNUTranslations class.
                                                             (line   79)
* npgettext() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   55)
* npgettext() (in module gettext):       GNU gettext API.    (line   67)
* NSIG (in module signal):               Module contents<3>. (line  239)
* nsmallest() (in module heapq):         heapq — Heap queue algorithm.
                                                             (line  117)
* NTEventLogHandler (class in logging.handlers): NTEventLogHandler.
                                                             (line   11)
* ntohl() (in module socket):            Other functions<2>. (line  224)
* ntohs() (in module socket):            Other functions<2>. (line  231)
* ntransfercmd() (ftplib.FTP method):    FTP objects.        (line  277)
* NUL (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   18)
* null; operation:                       The pass statement. (line    6)
* null; operation <1>:                   The pass statement. (line    6)
* nullcontext() (in module contextlib):  Utilities.          (line  217)
* NullHandler (class in logging):        NullHandler.        (line   12)
* NullTranslations (class in gettext):   The NullTranslations class.
                                                             (line   13)
* num_addresses (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  128)
* num_addresses (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  327)
* num_tickets (ssl.SSLContext attribute): SSL contexts.      (line  562)
* number:                                Numeric literals.   (line    6)
* Number (class in numbers):             numbers — Numeric abstract base classes.
                                                             (line   15)
* NUMBER (in module token):              token — Constants used with Python parse trees.
                                                             (line   50)
* number_class() (decimal.Context method): Context objects.  (line  439)
* number_class() (decimal.Decimal method): Decimal objects.  (line  439)
* numerator (fractions.Fraction attribute): fractions — Rational numbers.
                                                             (line  111)
* numerator (numbers.Rational attribute): The numeric tower. (line   51)
* numeric literal:                       Numeric literals.   (line    6)
* numeric; conversions:                  Numeric Types — int float complex.
                                                             (line  106)
* numeric; literals:                     Numeric Types — int float complex.
                                                             (line   19)
* numeric() (in module unicodedata):     unicodedata — Unicode Database.
                                                             (line   71)
* numinput() (in module turtle):         Input methods.      (line   22)
* O_APPEND (in module os):               File Descriptor Operations.
                                                             (line  420)
* O_ASYNC (in module os):                File Descriptor Operations.
                                                             (line  462)
* O_BINARY (in module os):               File Descriptor Operations.
                                                             (line  442)
* O_CLOEXEC (in module os):              File Descriptor Operations.
                                                             (line  430)
* O_CREAT (in module os):                File Descriptor Operations.
                                                             (line  420)
* O_DIRECT (in module os):               File Descriptor Operations.
                                                             (line  462)
* O_DIRECTORY (in module os):            File Descriptor Operations.
                                                             (line  462)
* O_DSYNC (in module os):                File Descriptor Operations.
                                                             (line  430)
* O_EVTONLY (in module os):              File Descriptor Operations.
                                                             (line  452)
* O_EXCL (in module os):                 File Descriptor Operations.
                                                             (line  420)
* O_EXLOCK (in module os):               File Descriptor Operations.
                                                             (line  462)
* O_FSYNC (in module os):                File Descriptor Operations.
                                                             (line  452)
* O_NDELAY (in module os):               File Descriptor Operations.
                                                             (line  430)
* O_NOATIME (in module os):              File Descriptor Operations.
                                                             (line  462)
* O_NOCTTY (in module os):               File Descriptor Operations.
                                                             (line  430)
* O_NOFOLLOW (in module os):             File Descriptor Operations.
                                                             (line  462)
* O_NOFOLLOW_ANY (in module os):         File Descriptor Operations.
                                                             (line  452)
* O_NOINHERIT (in module os):            File Descriptor Operations.
                                                             (line  442)
* O_NONBLOCK (in module os):             File Descriptor Operations.
                                                             (line  430)
* O_PATH (in module os):                 File Descriptor Operations.
                                                             (line  462)
* O_RANDOM (in module os):               File Descriptor Operations.
                                                             (line  442)
* O_RDONLY (in module os):               File Descriptor Operations.
                                                             (line  420)
* O_RDWR (in module os):                 File Descriptor Operations.
                                                             (line  420)
* O_RSYNC (in module os):                File Descriptor Operations.
                                                             (line  430)
* O_SEQUENTIAL (in module os):           File Descriptor Operations.
                                                             (line  442)
* O_SHLOCK (in module os):               File Descriptor Operations.
                                                             (line  462)
* O_SHORT_LIVED (in module os):          File Descriptor Operations.
                                                             (line  442)
* O_SYMLINK (in module os):              File Descriptor Operations.
                                                             (line  452)
* O_SYNC (in module os):                 File Descriptor Operations.
                                                             (line  430)
* O_TEMPORARY (in module os):            File Descriptor Operations.
                                                             (line  442)
* O_TEXT (in module os):                 File Descriptor Operations.
                                                             (line  442)
* O_TMPFILE (in module os):              File Descriptor Operations.
                                                             (line  462)
* O_TRUNC (in module os):                File Descriptor Operations.
                                                             (line  420)
* O_WRONLY (in module os):               File Descriptor Operations.
                                                             (line  420)
* obj (AttributeError attribute):        Concrete exceptions.
                                                             (line   26)
* obj (memoryview attribute):            Memory Views.       (line  372)
* object:                                Objects values and types.
                                                             (line    6)
* object <1>:                            Glossary.           (line 1210)
* object (built-in class):               Built-in Functions. (line 1235)
* object (UnicodeError attribute):       Concrete exceptions.
                                                             (line  451)
* object; asynchronous-generator:        Asynchronous generator functions<2>.
                                                             (line   66)
* object; Boolean:                       numbers Integral.   (line   27)
* object; Boolean <1>:                   Numeric Types — int float complex.
                                                             (line    6)
* object; built-in function:             Built-in functions. (line    6)
* object; built-in function <1>:         Calls.              (line  142)
* object; built-in method:               Built-in methods.   (line    6)
* object; built-in method <1>:           Calls.              (line  142)
* object; bytearray:                     Mutable Sequence Types.
                                                             (line    6)
* object; bytearray <1>:                 Binary Sequence Types — bytes bytearray memoryview.
                                                             (line    6)
* object; bytearray <2>:                 Bytearray Objects.  (line    6)
* object; bytearray <3>:                 Byte Array Objects. (line    6)
* object; bytes:                         Binary Sequence Types — bytes bytearray memoryview.
                                                             (line    6)
* object; bytes <1>:                     Bytes Objects.      (line    6)
* object; bytes <2>:                     Bytes Objects<2>.   (line    9)
* object; callable:                      Callable types.     (line    6)
* object; callable <1>:                  Slicings.           (line   39)
* object; Capsule:                       Capsules<2>.        (line    6)
* object; class:                         Custom classes.     (line   19)
* object; class <1>:                     Calls.              (line  147)
* object; class <2>:                     Class definitions.  (line    6)
* object; class instance:                Custom classes.     (line   19)
* object; class instance <1>:            Class instances.    (line    6)
* object; class instance <2>:            Calls.              (line  151)
* object; code:                          Code objects.       (line    6)
* object; code <1>:                      Methods.            (line   44)
* object; code <2>:                      marshal — Internal Python object serialization.
                                                             (line   33)
* object; code <3>:                      Cell Objects.       (line   58)
* object; complex:                       numbers Complex complex.
                                                             (line    6)
* object; complex number:                Numeric Types — int float complex.
                                                             (line    6)
* object; complex number <1>:            Complex Number Objects.
                                                             (line    6)
* object; deallocation:                  Finalization and De-allocation.
                                                             (line    6)
* object; dictionary:                    Dictionaries<2>.    (line    6)
* object; dictionary <1>:                Custom classes.     (line   19)
* object; dictionary <2>:                Basic customization.
                                                             (line  237)
* object; dictionary <3>:                Dictionary displays.
                                                             (line    6)
* object; dictionary <4>:                Subscriptions.      (line    6)
* object; dictionary <5>:                Assignment statements.
                                                             (line  115)
* object; dictionary <6>:                Mapping Types — dict.
                                                             (line    6)
* object; dictionary <7>:                Dictionary Objects. (line    6)
* object; Ellipsis:                      Ellipsis.           (line    6)
* object; file:                          Reading and Writing Files.
                                                             (line    6)
* object; file <1>:                      File Objects.       (line    6)
* object; finalization:                  Finalization and De-allocation.
                                                             (line    6)
* object; floating-point:                numbers Real float. (line    6)
* object; floating-point <1>:            Numeric Types — int float complex.
                                                             (line    6)
* object; floating-point <2>:            Floating-Point Objects.
                                                             (line    6)
* object; frame:                         Frame objects.      (line    6)
* object; frozenset:                     Set types.          (line   29)
* object; frozenset <1>:                 Set Objects.        (line    6)
* object; function:                      User-defined functions.
                                                             (line    6)
* object; function <1>:                  Built-in functions. (line    6)
* object; function <2>:                  Calls.              (line  132)
* object; function <3>:                  Calls.              (line  142)
* object; function <4>:                  Function definitions.
                                                             (line    6)
* object; function <5>:                  Function Objects<3>.
                                                             (line    6)
* object; generator:                     Special read-only attributes<2>.
                                                             (line   89)
* object; generator <1>:                 Generator expressions.
                                                             (line    6)
* object; generator <2>:                 Yield expressions.  (line  110)
* object; GenericAlias:                  Generic Alias Type. (line    6)
* object; immutable:                     Immutable sequences.
                                                             (line    6)
* object; immutable sequence:            Immutable sequences.
                                                             (line    6)
* object; instance:                      Custom classes.     (line   19)
* object; instance <1>:                  Class instances.    (line    6)
* object; instance <2>:                  Calls.              (line  151)
* object; instancemethod:                Instance Method Objects.
                                                             (line    6)
* object; integer:                       numbers Integral.   (line    6)
* object; integer <1>:                   Numeric Types — int float complex.
                                                             (line    6)
* object; integer <2>:                   Integer Objects.    (line    6)
* object; io.StringIO:                   Text Sequence Type — str.
                                                             (line   36)
* object; list:                          Mutable sequences.  (line   18)
* object; list <1>:                      List displays.      (line    6)
* object; list <2>:                      Attribute references.
                                                             (line   10)
* object; list <3>:                      Subscriptions.      (line    6)
* object; list <4>:                      Slicings.           (line    6)
* object; list <5>:                      Assignment statements.
                                                             (line  106)
* object; list <6>:                      Mutable Sequence Types.
                                                             (line    6)
* object; list <7>:                      Lists<2>.           (line    6)
* object; list <8>:                      List Objects.       (line    6)
* object; long integer:                  Integer Objects.    (line    6)
* object; mapping:                       Mappings.           (line    6)
* object; mapping <1>:                   Class instances.    (line   26)
* object; mapping <2>:                   Subscriptions.      (line    6)
* object; mapping <3>:                   Assignment statements.
                                                             (line  115)
* object; mapping <4>:                   Mapping Types — dict.
                                                             (line    6)
* object; mapping <5>:                   Container Objects.  (line    6)
* object; memoryview:                    Binary Sequence Types — bytes bytearray memoryview.
                                                             (line    6)
* object; memoryview <1>:                Ellipsis Object.    (line   19)
* object; method:                        Instance Objects.   (line   26)
* object; method <1>:                    Instance methods.   (line    6)
* object; method <2>:                    Built-in methods.   (line    6)
* object; method <3>:                    Calls.              (line  142)
* object; method <4>:                    Methods.            (line    6)
* object; method <5>:                    Method Objects<2>.  (line    6)
* object; module:                        Modules<3>.         (line    6)
* object; module <1>:                    Attribute references.
                                                             (line   10)
* object; module <2>:                    Module Objects.     (line    6)
* object; mutable:                       Mutable sequences.  (line    6)
* object; mutable <1>:                   Assignment statements.
                                                             (line    6)
* object; mutable <2>:                   Assignment statements.
                                                             (line  101)
* object; mutable sequence:              Mutable sequences.  (line    6)
* object; None:                          None.               (line    6)
* object; None <1>:                      Expression statements.
                                                             (line   17)
* object; None <2>:                      The None Object.    (line    6)
* object; NotImplemented:                NotImplemented.     (line    6)
* object; numeric:                       numbers Number.     (line    6)
* object; numeric <1>:                   Class instances.    (line   26)
* object; numeric <2>:                   Comparisons<2>.     (line   43)
* object; numeric <3>:                   Numeric Types — int float complex.
                                                             (line    6)
* object; numeric <4>:                   Numeric Objects.    (line    6)
* object; PickleBuffer:                  MemoryView objects. (line   82)
* object; range:                         Ranges.             (line    6)
* object; sequence:                      Sequences.          (line    6)
* object; sequence <1>:                  Class instances.    (line   26)
* object; sequence <2>:                  Subscriptions.      (line    6)
* object; sequence <3>:                  Slicings.           (line    6)
* object; sequence <4>:                  Membership test operations.
                                                             (line   36)
* object; sequence <5>:                  Assignment statements.
                                                             (line  106)
* object; sequence <6>:                  The for statement.  (line    6)
* object; sequence <7>:                  Common Sequence Operations.
                                                             (line    6)
* object; sequence <8>:                  Sequence Objects.   (line    6)
* object; set:                           Set types.          (line   23)
* object; set <1>:                       Set displays.       (line    6)
* object; set <2>:                       Set Types — set frozenset.
                                                             (line    6)
* object; set <3>:                       Set Objects.        (line    6)
* object; set type:                      Set types.          (line    6)
* object; slice:                         Emulating container types.
                                                             (line   71)
* object; socket:                        socket — Low-level networking interface.
                                                             (line   22)
* object; string:                        Subscriptions.      (line    6)
* object; string <1>:                    Slicings.           (line    6)
* object; string <2>:                    Ranges.             (line  125)
* object; traceback:                     Traceback objects.  (line    6)
* object; traceback <1>:                 The raise statement.
                                                             (line   21)
* object; traceback <2>:                 except clause.      (line   59)
* object; traceback <3>:                 sys — System-specific parameters and functions.
                                                             (line  459)
* object; traceback <4>:                 traceback — Print or retrieve a stack traceback.
                                                             (line   19)
* object; tuple:                         Immutable sequences.
                                                             (line   29)
* object; tuple <1>:                     Subscriptions.      (line    6)
* object; tuple <2>:                     Slicings.           (line    6)
* object; tuple <3>:                     Expression lists.   (line   13)
* object; tuple <4>:                     Immutable Sequence Types.
                                                             (line    6)
* object; tuple <5>:                     Tuples.             (line    6)
* object; tuple <6>:                     Tuple Objects.      (line    6)
* object; type:                          Built-in Functions. (line 2009)
* object; type <1>:                      Objects Types and Reference Counts.
                                                             (line    6)
* object; type <2>:                      Type Objects<2>.    (line    6)
* object; Union:                         Union Type.         (line    6)
* object; user-defined function:         User-defined functions.
                                                             (line    6)
* object; user-defined function <1>:     Calls.              (line  132)
* object; user-defined function <2>:     Function definitions.
                                                             (line    6)
* object; user-defined method:           Instance methods.   (line    6)
* object.__match_args__ (built-in variable): Customizing positional arguments in class pattern matching.
                                                             (line   12)
* object.__slots__ (built-in variable):  __slots__<2>.       (line   14)
* objects; comparing:                    Comparisons<2>.     (line   43)
* objobjargproc (C type):                Slot Type typedefs. (line  138)
* objobjproc (C type):                   Slot Type typedefs. (line  134)
* octal literal:                         Numeric literals.   (line    6)
* octal; literals:                       Numeric Types — int float complex.
                                                             (line   19)
* octdigits (in module string):          String constants.   (line   32)
* OCTOBER (in module calendar):          calendar — General calendar-related functions.
                                                             (line  488)
* offset (SyntaxError attribute):        Concrete exceptions.
                                                             (line  325)
* offset (tarfile.TarInfo attribute):    TarInfo Objects.    (line  149)
* offset (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line  110)
* offset (xml.parsers.expat.ExpatError attribute): ExpatError Exceptions.
                                                             (line   32)
* offset_data (tarfile.TarInfo attribute): TarInfo Objects.  (line  153)
* OK (in module curses):                 Constants<6>.       (line   13)
* OK (in module tkinter.messagebox):     tkinter messagebox — Tkinter message prompts.
                                                             (line  153)
* ok_command() (tkinter.filedialog.LoadFileDialog method): Native Load/Save Dialogs.
                                                             (line  140)
* ok_command() (tkinter.filedialog.SaveFileDialog method): Native Load/Save Dialogs.
                                                             (line  150)
* ok_event() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  119)
* OKCANCEL (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  171)
* old_value (contextvars.Token attribute): Context Variables.
                                                             (line   90)
* OleDLL (class in ctypes):              Loading shared libraries.
                                                             (line   34)
* on_motion() (tkinter.dnd.DndHandler method): tkinter dnd — Drag and drop support.
                                                             (line   56)
* on_release() (tkinter.dnd.DndHandler method): tkinter dnd — Drag and drop support.
                                                             (line   61)
* onclick() (in module turtle):          Using screen events.
                                                             (line   56)
* ondrag() (in module turtle):           Using events.       (line   57)
* onecmd() (cmd.Cmd method):             Cmd Objects.        (line   58)
* onkey() (in module turtle):            Using screen events.
                                                             (line   12)
* onkeypress() (in module turtle):       Using screen events.
                                                             (line   35)
* onkeyrelease() (in module turtle):     Using screen events.
                                                             (line   12)
* onrelease() (in module turtle):        Using events.       (line   30)
* onscreenclick() (in module turtle):    Using screen events.
                                                             (line   56)
* ontimer() (in module turtle):          Using screen events.
                                                             (line   86)
* OP (in module token):                  token — Constants used with Python parse trees.
                                                             (line   62)
* OP_ALL (in module ssl):                Constants<9>.       (line  211)
* OP_CIPHER_SERVER_PREFERENCE (in module ssl): Constants<9>. (line  300)
* OP_ENABLE_KTLS (in module ssl):        Constants<9>.       (line  358)
* OP_ENABLE_MIDDLEBOX_COMPAT (in module ssl): Constants<9>.  (line  324)
* OP_IGNORE_UNEXPECTED_EOF (in module ssl): Constants<9>.    (line  350)
* OP_LEGACY_SERVER_CONNECT (in module ssl): Constants<9>.    (line  375)
* OP_NO_COMPRESSION (in module ssl):     Constants<9>.       (line  333)
* OP_NO_RENEGOTIATION (in module ssl):   Constants<9>.       (line  290)
* OP_NO_SSLv2 (in module ssl):           Constants<9>.       (line  219)
* OP_NO_SSLv3 (in module ssl):           Constants<9>.       (line  229)
* OP_NO_TICKET (in module ssl):          Constants<9>.       (line  344)
* OP_NO_TLSv1 (in module ssl):           Constants<9>.       (line  239)
* OP_NO_TLSv1_1 (in module ssl):         Constants<9>.       (line  251)
* OP_NO_TLSv1_2 (in module ssl):         Constants<9>.       (line  263)
* OP_NO_TLSv1_3 (in module ssl):         Constants<9>.       (line  275)
* OP_SINGLE_DH_USE (in module ssl):      Constants<9>.       (line  308)
* OP_SINGLE_ECDH_USE (in module ssl):    Constants<9>.       (line  316)
* Open (class in tkinter.filedialog):    Native Load/Save Dialogs.
                                                             (line   60)
* open_binary() (in module importlib.resources): Functional API.
                                                             (line   35)
* open_code() (in module io):            High-level Module Interface.
                                                             (line   22)
* open_connection() (in module asyncio): Streams.            (line   42)
* open_flags (in module dbm.gnu):        dbm gnu — GNU database manager.
                                                             (line   30)
* open_new_tab() (in module webbrowser): Command-line interface<4>.
                                                             (line   60)
* open_new_tab() (webbrowser.controller method): Browser controller objects.
                                                             (line   26)
* open_new() (in module webbrowser):     Command-line interface<4>.
                                                             (line   52)
* open_new() (webbrowser.controller method): Browser controller objects.
                                                             (line   20)
* open_osfhandle() (in module msvcrt):   File Operations.    (line   44)
* open_resource() (importlib.abc.ResourceReader method): importlib abc – Abstract base classes related to import.
                                                             (line  467)
* open_resource() (importlib.resources.abc.ResourceReader method): importlib resources abc – Abstract base classes for resources.
                                                             (line   47)
* open_text() (in module importlib.resources): Functional API.
                                                             (line   51)
* open_unix_connection() (in module asyncio): Streams.       (line  118)
* open_unknown() (urllib.request.URLopener method): Legacy interface.
                                                             (line  108)
* open_urlresource() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  584)
* open() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  173)
* open() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  544)
* open() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  144)
* open() (in module bz2):                De compression of files.
                                                             (line    6)
* open() (in module codecs):             codecs — Codec registry and base classes.
                                                             (line  182)
* open() (in module dbm.dumb):           dbm dumb — Portable DBM implementation.
                                                             (line   27)
* open() (in module dbm.gnu):            dbm gnu — GNU database manager.
                                                             (line   35)
* open() (in module dbm.ndbm):           dbm ndbm — New Database Manager.
                                                             (line   40)
* open() (in module dbm.sqlite3):        dbm sqlite3 — SQLite backend for dbm.
                                                             (line   22)
* open() (in module dbm):                dbm — Interfaces to Unix “databases”.
                                                             (line   49)
* open() (in module gzip):               gzip — Support for gzip files.
                                                             (line   27)
* open() (in module io):                 High-level Module Interface.
                                                             (line   12)
* open() (in module lzma):               Reading and writing compressed files.
                                                             (line    6)
* open() (in module os):                 File Descriptor Operations.
                                                             (line  375)
* open() (in module shelve):             shelve — Python object persistence.
                                                             (line   17)
* open() (in module tarfile):            tarfile — Read and write tar archive files.
                                                             (line   41)
* open() (in module tokenize):           Tokenizing Input.   (line   96)
* open() (in module wave):               wave — Read and write WAV files.
                                                             (line   20)
* open() (in module webbrowser):         Command-line interface<4>.
                                                             (line   32)
* open() (pathlib.Path method):          Reading and writing files.
                                                             (line    6)
* open() (tarfile.TarFile class method): TarFile Objects.    (line   97)
* open() (urllib.request.OpenerDirector method): OpenerDirector Objects.
                                                             (line   46)
* open() (urllib.request.URLopener method): Legacy interface.
                                                             (line   97)
* open() (webbrowser.controller method): Browser controller objects.
                                                             (line   14)
* open() (zipfile.Path method):          Path objects.       (line   35)
* open() (zipfile.ZipFile method):       ZipFile objects.    (line  129)
* OpenerDirector (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  272)
* OpenKey() (in module winreg):          Functions<13>.      (line  285)
* OpenKeyEx() (in module winreg):        Functions<13>.      (line  285)
* openlog() (in module syslog):          syslog — Unix syslog library routines.
                                                             (line   50)
* openpty() (in module os):              File Descriptor Operations.
                                                             (line  478)
* openpty() (in module pty):             pty — Pseudo-terminal utilities.
                                                             (line   35)
* OPENSSL_VERSION (in module ssl):       Constants<9>.       (line  479)
* OPENSSL_VERSION_INFO (in module ssl):  Constants<9>.       (line  489)
* OPENSSL_VERSION_NUMBER (in module ssl): Constants<9>.      (line  499)
* OpenSSL; (use in module hashlib):      Hash algorithms.    (line   18)
* OpenSSL; (use in module ssl):          ssl — TLS/SSL wrapper for socket objects.
                                                             (line    8)
* OperationalError:                      Exceptions<7>.      (line   57)
* operations on; dictionary; type:       Mapping Types — dict.
                                                             (line    6)
* operations on; integer; types:         Bitwise Operations on Integer Types.
                                                             (line    6)
* operations on; list; type:             Mutable Sequence Types.
                                                             (line   16)
* operations on; mapping; types:         Mapping Types — dict.
                                                             (line    6)
* operations on; numeric; types:         Numeric Types — int float complex.
                                                             (line   94)
* operations on; sequence; types:        Common Sequence Operations.
                                                             (line   21)
* operations on; sequence; types <1>:    Mutable Sequence Types.
                                                             (line   16)
* operator; - (minus):                   Unary arithmetic and bitwise operations.
                                                             (line   10)
* operator; - (minus) <1>:               Binary arithmetic operations.
                                                             (line   83)
* operator; - (minus) <2>:               Numeric Types — int float complex.
                                                             (line   27)
* operator; !=:                          Comparisons.        (line    6)
* operator; != <1>:                      Comparisons<2>.     (line    6)
* operator; @ (at):                      Binary arithmetic operations.
                                                             (line   26)
* operator; * (asterisk):                Binary arithmetic operations.
                                                             (line   16)
* operator; * (asterisk) <1>:            Numeric Types — int float complex.
                                                             (line   27)
* operator; **:                          The power operator. (line    6)
* operator; ** <1>:                      Numeric Types — int float complex.
                                                             (line   27)
* operator; / (slash):                   Binary arithmetic operations.
                                                             (line   34)
* operator; / (slash) <1>:               Numeric Types — int float complex.
                                                             (line   27)
* operator; //:                          Binary arithmetic operations.
                                                             (line   34)
* operator; // <1>:                      Numeric Types — int float complex.
                                                             (line   27)
* operator; & (ampersand):               Binary bitwise operations.
                                                             (line   12)
* operator; & (ampersand) <1>:           Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; % (percent):                 Binary arithmetic operations.
                                                             (line   46)
* operator; % (percent) <1>:             Numeric Types — int float complex.
                                                             (line   27)
* operator; ^ (caret):                   Binary bitwise operations.
                                                             (line   16)
* operator; ^ (caret) <1>:               Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; + (plus):                    Unary arithmetic and bitwise operations.
                                                             (line   14)
* operator; + (plus) <1>:                Binary arithmetic operations.
                                                             (line   74)
* operator; + (plus) <2>:                Numeric Types — int float complex.
                                                             (line   27)
* operator; < (less):                    Comparisons.        (line    6)
* operator; < (less) <1>:                Comparisons<2>.     (line    6)
* operator; <<:                          Shifting operations.
                                                             (line    6)
* operator; << <1>:                      Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; <=:                          Comparisons.        (line    6)
* operator; <= <1>:                      Comparisons<2>.     (line    6)
* operator; ==:                          Comparisons.        (line    6)
* operator; == <1>:                      Comparisons<2>.     (line    6)
* operator; > (greater):                 Comparisons.        (line    6)
* operator; > (greater) <1>:             Comparisons<2>.     (line    6)
* operator; >=:                          Comparisons.        (line    6)
* operator; >= <1>:                      Comparisons<2>.     (line    6)
* operator; >>:                          Shifting operations.
                                                             (line    6)
* operator; >> <1>:                      Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; | (vertical bar):            Binary bitwise operations.
                                                             (line   20)
* operator; | (vertical bar) <1>:        Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; ~ (tilde):                   Unary arithmetic and bitwise operations.
                                                             (line   18)
* operator; ~ (tilde) <1>:               Bitwise Operations on Integer Types.
                                                             (line    6)
* operator; and:                         Boolean operations. (line   21)
* operator; and <1>:                     Truth Value Testing.
                                                             (line   23)
* operator; and <2>:                     Boolean Operations — and or not.
                                                             (line   22)
* operator; comparison:                  Comparisons<2>.     (line    6)
* operator; in:                          Membership test operations.
                                                             (line   36)
* operator; in <1>:                      Comparisons<2>.     (line   64)
* operator; in <2>:                      Common Sequence Operations.
                                                             (line   21)
* operator; is:                          Membership test operations.
                                                             (line   39)
* operator; is <1>:                      Comparisons<2>.     (line    6)
* operator; is not:                      Membership test operations.
                                                             (line   39)
* operator; is not <1>:                  Comparisons<2>.     (line    6)
* operator; not:                         Boolean operations. (line   18)
* operator; not <1>:                     Boolean Operations — and or not.
                                                             (line   22)
* operator; not in:                      Membership test operations.
                                                             (line   36)
* operator; not in <1>:                  Comparisons<2>.     (line   64)
* operator; not in <2>:                  Common Sequence Operations.
                                                             (line   21)
* operator; or:                          Boolean operations. (line   25)
* operator; or <1>:                      Truth Value Testing.
                                                             (line   23)
* operator; or <2>:                      Boolean Operations — and or not.
                                                             (line   22)
* operator; overloading:                 Special method names.
                                                             (line    6)
* operator; precedence:                  Operator precedence.
                                                             (line    6)
* operators:                             Operators.          (line    6)
* opmap (in module dis):                 Opcode collections. (line   17)
* opname (in module dis):                Opcode collections. (line   13)
* OPT:                                   Debug options.      (line   39)
* optim_args_from_interpreter_flags() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  327)
* optimize (sys.flags attribute):        sys — System-specific parameters and functions.
                                                             (line  539)
* optimize() (in module pickletools):    Programmatic Interface<2>.
                                                             (line   31)
* optimized scope:                       Glossary.           (line 1216)
* OPTIMIZED_BYTECODE_SUFFIXES (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   30)
* Option (class in optparse):            Option attributes.  (line    6)
* Optional (in module typing):           Special forms.      (line   52)
* OptionConflictError:                   Exceptions<10>.     (line   11)
* OptionError:                           Exceptions<10>.     (line    6)
* OptionGroup (class in optparse):       Grouping Options.   (line   12)
* OptionParser (class in optparse):      Creating the parser.
                                                             (line    9)
* Options (class in ssl):                Constants<9>.       (line  340)
* options (doctest.Example attribute):   Example Objects.    (line   52)
* options (ssl.SSLContext attribute):    SSL contexts.       (line  570)
* options() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  137)
* OptionValueError:                      Exceptions<10>.     (line   16)
* optionxform() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  319)
* Or (class in ast):                     Expressions<2>.     (line   86)
* or_() (in module operator):            operator — Standard operators as functions.
                                                             (line  137)
* ordered_attributes (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  194)
* OrderedDict (class in collections):    OrderedDict objects.
                                                             (line   60)
* OrderedDict (class in typing):         Aliases to types in collections.
                                                             (line   17)
* orig_argv (in module sys):             sys — System-specific parameters and functions.
                                                             (line 1314)
* origin (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  392)
* origin_req_host (urllib.request.Request attribute): Request Objects.
                                                             (line   30)
* origin_server (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  292)
* os_environ (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  167)
* OSError:                               Concrete exceptions.
                                                             (line  150)
* OUT_TO_DEFAULT (in module msvcrt):     Other Functions.    (line   20)
* OUT_TO_MSGBOX (in module msvcrt):      Other Functions.    (line   30)
* OUT_TO_STDERR (in module msvcrt):      Other Functions.    (line   25)
* output:                                Expression statements.
                                                             (line   17)
* output (subprocess.CalledProcessError attribute): Using the subprocess Module.
                                                             (line  220)
* output (subprocess.TimeoutExpired attribute): Using the subprocess Module.
                                                             (line  181)
* output (unittest.TestCase attribute):  Test cases.         (line  436)
* output_charset (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   74)
* output_codec (email.charset.Charset attribute): email charset Representing character sets.
                                                             (line   88)
* output_difference() (doctest.OutputChecker method): OutputChecker objects.
                                                             (line   27)
* output() (http.cookies.BaseCookie method): Cookie Objects. (line   23)
* output() (http.cookies.Morsel method): Morsel Objects.     (line   69)
* OutputChecker (class in doctest):      OutputChecker objects.
                                                             (line    6)
* OutputString() (http.cookies.Morsel method): Morsel Objects.
                                                             (line   84)
* OutsideDestinationError:               tarfile — Read and write tar archive files.
                                                             (line  242)
* Overflow (class in decimal):           Signals.            (line   68)
* OverflowError:                         Concrete exceptions.
                                                             (line  215)
* OverflowError (built-in exception):    Integer Objects.    (line  152)
* OverflowError (built-in exception) <1>: Integer Objects.   (line  207)
* OverflowError (built-in exception) <2>: Integer Objects.   (line  249)
* OverflowError (built-in exception) <3>: Integer Objects.   (line  261)
* OverflowError (built-in exception) <4>: Integer Objects.   (line  273)
* OverflowError (built-in exception) <5>: Integer Objects.   (line  286)
* overlap() (statistics.NormalDist method): NormalDist objects.
                                                             (line  102)
* overlaps() (ipaddress.IPv4Network method): Network objects.
                                                             (line  155)
* overlaps() (ipaddress.IPv6Network method): Network objects.
                                                             (line  340)
* overlay() (curses.window method):      Window Objects.     (line  431)
* overload() (in module typing):         Functions and decorators.
                                                             (line  247)
* override() (in module typing):         Functions and decorators.
                                                             (line  372)
* overwrite() (curses.window method):    Window Objects.     (line  444)
* owner() (pathlib.Path method):         Permissions and ownership.
                                                             (line    6)
* p (pdb command):                       Debugger commands.  (line  267)
* P_ALL (in module os):                  Process Management. (line  956)
* P_DETACH (in module os):               Process Management. (line  687)
* P_NOWAIT (in module os):               Process Management. (line  667)
* P_NOWAITO (in module os):              Process Management. (line  667)
* P_OVERLAY (in module os):              Process Management. (line  687)
* P_PGID (in module os):                 Process Management. (line  956)
* P_PID (in module os):                  Process Management. (line  956)
* P_PIDFD (in module os):                Process Management. (line  956)
* P_WAIT (in module os):                 Process Management. (line  677)
* pack_into() (in module struct):        Functions and Exceptions.
                                                             (line   19)
* pack_into() (struct.Struct method):    Classes<3>.         (line   29)
* pack() (in module struct):             Functions and Exceptions.
                                                             (line   13)
* pack() (mailbox.MH method):            MH objects.         (line   67)
* pack() (struct.Struct method):         Classes<3>.         (line   24)
* package:                               Packages<2>.        (line    6)
* package <1>:                           site — Site-specific configuration hook.
                                                             (line   74)
* package <2>:                           Glossary.           (line 1227)
* package variable; __all__:             Importing Modules<2>.
                                                             (line    9)
* package; namespace:                    Namespace packages. (line    6)
* package; portion:                      Namespace packages. (line    6)
* package; regular:                      Regular packages.   (line    6)
* PackageMetadata (class in importlib.metadata): Distribution metadata.
                                                             (line   14)
* PackageNotFoundError:                  Overview<3>.        (line   35)
* PackagePath (class in importlib.metadata): Distribution files.
                                                             (line   18)
* packages_distributions() (in module importlib.metadata): Mapping import to distribution packages.
                                                             (line    6)
* packed (ipaddress.IPv4Address attribute): Address objects. (line   71)
* packed (ipaddress.IPv6Address attribute): Address objects. (line  267)
* packing (widgets):                     The Packer.         (line    6)
* packing; binary; data:                 struct — Interpret bytes as packed binary data.
                                                             (line    8)
* PAGER:                                 pydoc — Documentation generator and online help system.
                                                             (line   46)
* pair_content() (in module curses):     Functions<6>.       (line  379)
* pair_number() (in module curses):      Functions<6>.       (line  385)
* pairwise() (in module itertools):      Itertool Functions. (line  413)
* parallelism:                           Glossary.           (line 1236)
* parameter:                             Glossary.           (line 1247)
* Parameter (class in inspect):          Introspecting callables with the Signature object.
                                                             (line  188)
* parameter; call semantics:             Calls.              (line   25)
* parameter; difference from argument:   How can I pass optional or keyword parameters from one function to another?.
                                                             (line   16)
* parameter; function definition:        Class Patterns.     (line  140)
* ParameterizedMIMEHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  254)
* parameters (inspect.Signature attribute): Introspecting callables with the Signature object.
                                                             (line  104)
* params (email.headerregistry.ParameterizedMIMEHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  262)
* ParamSpec (class in ast):              Type parameters.    (line   36)
* ParamSpec (class in typing):           Building generic types and type aliases.
                                                             (line  351)
* ParamSpecArgs (in module typing):      Building generic types and type aliases.
                                                             (line  471)
* ParamSpecKwargs (in module typing):    Building generic types and type aliases.
                                                             (line  471)
* paramstyle (in module sqlite3):        Module constants.   (line   70)
* pardir (in module os):                 Miscellaneous System Information.
                                                             (line  109)
* parent (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  428)
* parent (logging.Logger attribute):     Logger Objects.     (line   42)
* parent (pathlib.PurePath attribute):   Methods and properties.
                                                             (line   94)
* parent (pyclbr.Class attribute):       Class Objects<2>.   (line   28)
* parent (pyclbr.Function attribute):    Function Objects.   (line   27)
* parent (urllib.request.BaseHandler attribute): BaseHandler Objects.
                                                             (line   25)
* parent_process() (in module multiprocessing): Miscellaneous<3>.
                                                             (line   42)
* parent() (tkinter.ttk.Treeview method): ttk Treeview.      (line  227)
* parenthesized form:                    Parenthesized forms.
                                                             (line    6)
* parentNode (xml.dom.Node attribute):   Node Objects.       (line   17)
* parents (collections.ChainMap attribute): ChainMap objects.
                                                             (line   62)
* parents (pathlib.PurePath attribute):  Methods and properties.
                                                             (line   78)
* paretovariate() (in module random):    Real-valued distributions.
                                                             (line  101)
* parse_and_bind() (in module readline): Init file.          (line    8)
* parse_args() (argparse.ArgumentParser method): The parse_args method.
                                                             (line    6)
* parse_args() (optparse.OptionParser method): Parsing arguments.
                                                             (line    9)
* PARSE_COLNAMES (in module sqlite3):    Module constants.   (line   35)
* parse_config_h() (in module sysconfig): Other functions<3>.
                                                             (line   53)
* PARSE_DECLTYPES (in module sqlite3):   Module constants.   (line   13)
* parse_headers() (in module http.client): http client — HTTP protocol client.
                                                             (line  110)
* parse_intermixed_args() (argparse.ArgumentParser method): Intermixed parsing.
                                                             (line    6)
* parse_known_args() (argparse.ArgumentParser method): Partial parsing.
                                                             (line    6)
* parse_known_intermixed_args() (argparse.ArgumentParser method): Intermixed parsing.
                                                             (line    9)
* parse_qs() (in module urllib.parse):   URL Parsing.        (line  160)
* parse_qsl() (in module urllib.parse):  URL Parsing.        (line  206)
* parse() (doctest.DocTestParser method): DocTestParser objects.
                                                             (line   29)
* parse() (email.parser.BytesParser method): Parser API.     (line   34)
* parse() (email.parser.Parser method):  Parser API.         (line   86)
* parse() (in module ast):               ast Helpers.        (line    9)
* parse() (in module xml.dom.minidom):   xml dom minidom — Minimal DOM implementation.
                                                             (line   35)
* parse() (in module xml.dom.pulldom):   xml dom pulldom — Support for building partial DOM trees.
                                                             (line   84)
* parse() (in module xml.etree.ElementTree): Functions<9>.   (line  176)
* parse() (in module xml.sax):           xml sax — Support for SAX2 parsers.
                                                             (line   38)
* parse() (string.Formatter method):     Custom string formatting.
                                                             (line   40)
* parse() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   29)
* parse() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   54)
* Parse() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line    8)
* parse() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line    8)
* parseaddr() (in module email.utils):   email utils Miscellaneous utilities.
                                                             (line   57)
* parsebytes() (email.parser.BytesParser method): Parser API.
                                                             (line   54)
* parsedate_to_datetime() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  129)
* parsedate_tz() (in module email.utils): email utils Miscellaneous utilities.
                                                             (line  118)
* parsedate() (in module email.utils):   email utils Miscellaneous utilities.
                                                             (line  107)
* ParseError (class in xml.etree.ElementTree): Exceptions<19>.
                                                             (line    6)
* ParseFile() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   16)
* ParseFlags() (in module imaplib):      imaplib — IMAP4 protocol client.
                                                             (line  123)
* parser:                                Lexical analysis.   (line    6)
* Parser (class in email.parser):        Parser API.         (line   75)
* parser (pathlib.PurePath attribute):   Methods and properties.
                                                             (line    8)
* ParserCreate() (in module xml.parsers.expat): xml parsers expat — Fast XML parsing using Expat.
                                                             (line   45)
* ParseResult (class in urllib.parse):   Structured Parse Results.
                                                             (line   48)
* ParseResultBytes (class in urllib.parse): Structured Parse Results.
                                                             (line   73)
* parsestr() (email.parser.Parser method): Parser API.       (line   96)
* parseString() (in module xml.dom.minidom): xml dom minidom — Minimal DOM implementation.
                                                             (line   48)
* parseString() (in module xml.dom.pulldom): xml dom pulldom — Support for building partial DOM trees.
                                                             (line   97)
* parseString() (in module xml.sax):     xml sax — Support for SAX2 parsers.
                                                             (line   49)
* ParsingError:                          Exceptions<8>.      (line   65)
* partial (asyncio.IncompleteReadError attribute): Exceptions<13>.
                                                             (line   55)
* partial() (imaplib.IMAP4 method):      IMAP4 Objects.      (line  192)
* partial() (in module functools):       functools — Higher-order functions and operations on callable objects.
                                                             (line  319)
* partialmethod (class in functools):    functools — Higher-order functions and operations on callable objects.
                                                             (line  350)
* parties (asyncio.Barrier attribute):   Barrier.            (line   93)
* parties (threading.Barrier attribute): Barrier objects.    (line   92)
* partition() (bytearray method):        Bytes and Bytearray Operations.
                                                             (line  187)
* partition() (bytes method):            Bytes and Bytearray Operations.
                                                             (line  187)
* partition() (str method):              String Methods<2>.  (line  537)
* parts (pathlib.PurePath attribute):    Accessing individual parts.
                                                             (line    9)
* Pass (class in ast):                   Statements.         (line  153)
* pass_() (poplib.POP3 method):          POP3 Objects.       (line   36)
* Paste:                                 Help menu Shell and Editor.
                                                             (line   30)
* patch.dict() (in module unittest.mock): patch dict.        (line    6)
* patch.multiple() (in module unittest.mock): patch multiple.
                                                             (line    6)
* patch.object() (in module unittest.mock): patch object.    (line    6)
* patch.stopall() (in module unittest.mock): patch methods start and stop.
                                                             (line   70)
* patch() (in module test.support):      test support — Utilities for the Python test suite.
                                                             (line  655)
* patch() (in module unittest.mock):     patch.              (line    9)
* PATH:                                  Changes in the Python API<5>.
                                                             (line  145)
* PATH <1>:                              Changes in ‘python’ Command Behavior<2>.
                                                             (line    6)
* PATH <2>:                              Changes in ‘python’ Command Behavior<2>.
                                                             (line   11)
* PATH <3>:                              Changes in ‘python’ Command Behavior<2>.
                                                             (line   12)
* PATH <4>:                              macOS<9>.           (line   14)
* PATH <5>:                              Windows<27>.        (line   55)
* PATH <6>:                              Windows<31>.        (line   14)
* PATH <7>:                              Security<41>.       (line   16)
* PATH <8>:                              Security<41>.       (line   20)
* PATH <9>:                              The Module Search Path.
                                                             (line   17)
* PATH <10>:                             Executable Python Scripts.
                                                             (line   11)
* PATH <11>:                             Environment variables.
                                                             (line   26)
* PATH <12>:                             Miscellaneous.      (line   16)
* PATH <13>:                             Installation steps. (line   34)
* PATH <14>:                             Installation steps. (line   58)
* PATH <15>:                             Installing Without UI.
                                                             (line   77)
* PATH <16>:                             Installing Without UI.
                                                             (line   81)
* PATH <17>:                             Excursus Setting environment variables.
                                                             (line   23)
* PATH <18>:                             Excursus Setting environment variables.
                                                             (line   35)
* PATH <19>:                             Finding the Python executable.
                                                             (line   14)
* PATH <20>:                             Finding the Python executable.
                                                             (line   21)
* PATH <21>:                             Finding the Python executable.
                                                             (line   22)
* PATH <22>:                             Python Launcher for Windows.
                                                             (line   13)
* PATH <23>:                             From the command-line.
                                                             (line    9)
* PATH <24>:                             Shebang Lines.      (line   54)
* PATH <25>:                             Shebang Lines.      (line   60)
* PATH <26>:                             Shebang Lines.      (line   62)
* PATH <27>:                             Shebang Lines.      (line   67)
* PATH <28>:                             Comparison to the os and os path modules.
                                                             (line   41)
* PATH <29>:                             Directory and files operations.
                                                             (line  431)
* PATH <30>:                             Directory and files operations.
                                                             (line  436)
* PATH <31>:                             Process Management. (line   45)
* PATH <32>:                             Process Management. (line   84)
* PATH <33>:                             Process Management. (line   88)
* PATH <34>:                             Process Management. (line   89)
* PATH <35>:                             Process Management. (line  540)
* PATH <36>:                             Process Management. (line  626)
* PATH <37>:                             Process Management. (line  630)
* PATH <38>:                             Process Management. (line  631)
* PATH <39>:                             Miscellaneous System Information.
                                                             (line  140)
* PATH <40>:                             Popen Constructor.  (line   34)
* PATH <41>:                             webbrowser — Convenient web-browser controller.
                                                             (line   52)
* PATH <42>:                             How venvs work.     (line   16)
* PATH <43>:                             How venvs work.     (line   61)
* PATH <44>:                             How venvs work.     (line   66)
* PATH <45>:                             site — Site-specific configuration hook.
                                                             (line   66)
* PATH <46>:                             Embedding Python<2>.
                                                             (line   31)
* PATH <47>:                             Embedding Python<2>.
                                                             (line   37)
* PATH <48>:                             How do I make a Python script executable on Unix?.
                                                             (line   24)
* PATH <49>:                             How do I make a Python script executable on Unix?.
                                                             (line   28)
* Path (class in pathlib):               Concrete paths.     (line   11)
* Path (class in zipfile):               Path objects.       (line    6)
* path (http.cookiejar.Cookie attribute): Cookie Objects<2>. (line   44)
* path (http.cookies.Morsel attribute):  Morsel Objects.     (line   13)
* path (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   96)
* path (ImportError attribute):          Concrete exceptions.
                                                             (line   65)
* path (importlib.abc.FileLoader attribute): importlib abc – Abstract base classes related to import.
                                                             (line  306)
* path (importlib.machinery.AppleFrameworkLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  504)
* path (importlib.machinery.ExtensionFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  310)
* path (importlib.machinery.FileFinder attribute): importlib machinery – Importers and path hooks.
                                                             (line  179)
* path (importlib.machinery.SourceFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  216)
* path (importlib.machinery.SourcelessFileLoader attribute): importlib machinery – Importers and path hooks.
                                                             (line  260)
* path (in module sys):                  sys — System-specific parameters and functions.
                                                             (line 1327)
* path (in module sys) <1>:              Embedding Python<2>.
                                                             (line   12)
* path (in module sys) <2>:              Initializing and finalizing the interpreter.
                                                             (line    7)
* path (in module sys) <3>:              Process-wide parameters.
                                                             (line  136)
* path (os.DirEntry attribute):          Files and Directories.
                                                             (line  947)
* path based finder:                     The Path Based Finder.
                                                             (line    6)
* path based finder <1>:                 Glossary.           (line 1330)
* Path browser:                          File menu Shell and Editor.
                                                             (line   22)
* path entry:                            Glossary.           (line 1310)
* path entry finder:                     Glossary.           (line 1315)
* path entry hook:                       Glossary.           (line 1324)
* path hooks:                            Import hooks.       (line    6)
* path_hook() (importlib.machinery.FileFinder class method): importlib machinery – Importers and path hooks.
                                                             (line  194)
* path_hooks (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1360)
* path_importer_cache (in module sys):   sys — System-specific parameters and functions.
                                                             (line 1369)
* path_mtime() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  372)
* path_return_ok() (http.cookiejar.CookiePolicy method): CookiePolicy Objects.
                                                             (line   55)
* path_stats() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  350)
* path_stats() (importlib.machinery.SourceFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  225)
* path-like object:                      Glossary.           (line 1335)
* path; configuration; file:             site — Site-specific configuration hook.
                                                             (line   74)
* path; operations:                      pathlib — Object-oriented filesystem paths.
                                                             (line   10)
* path; operations <1>:                  os path — Common pathname manipulations.
                                                             (line    9)
* Path.stem (in module zipfile):         Path objects.       (line   86)
* Path.suffix (in module zipfile):       Path objects.       (line   79)
* Path.suffixes (in module zipfile):     Path objects.       (line   92)
* path() (in module importlib.resources): Functional API.    (line  110)
* pathconf_names (in module os):         Files and Directories.
                                                             (line  661)
* pathconf() (in module os):             Files and Directories.
                                                             (line  637)
* PathEntryFinder (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line   58)
* PATHEXT:                               Other Improvements<2>.
                                                             (line   30)
* PATHEXT <1>:                           Library<111>.       (line  138)
* PATHEXT <2>:                           Installing Without UI.
                                                             (line   77)
* PATHEXT <3>:                           Installing Without UI.
                                                             (line   81)
* PATHEXT <4>:                           Directory and files operations.
                                                             (line  446)
* PathFinder (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  107)
* PathLike (class in os):                Process Parameters. (line  118)
* pathname2url() (in module urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  143)
* pathsep (in module os):                Miscellaneous System Information.
                                                             (line  137)
* Pattern (class in re):                 Regular Expression Objects.
                                                             (line    6)
* Pattern (class in typing):             Aliases to other concrete types.
                                                             (line    6)
* pattern (re.Pattern attribute):        Regular Expression Objects.
                                                             (line  124)
* pattern (re.PatternError attribute):   Exceptions<3>.      (line   19)
* pattern matching:                      The match statement.
                                                             (line    6)
* PatternError:                          Exceptions<3>.      (line    6)
* pause_reading() (asyncio.ReadTransport method): Read-only Transports.
                                                             (line   12)
* pause_writing() (asyncio.BaseProtocol method): Base Protocol.
                                                             (line   40)
* pause() (in module signal):            Module contents<3>. (line  342)
* PAX_FORMAT (in module tarfile):        tarfile — Read and write tar archive files.
                                                             (line  334)
* pax_headers (tarfile.TarFile attribute): TarFile Objects.  (line  328)
* pax_headers (tarfile.TarInfo attribute): TarInfo Objects.  (line  161)
* pbkdf2_hmac() (in module hashlib):     Key derivation.     (line   11)
* pd() (in module turtle):               Drawing state.      (line    6)
* Pdb (class in pdb):                    pdb — The Python Debugger.
                                                             (line   17)
* Pdb (class in pdb) <1>:                Command-line interface<6>.
                                                             (line  126)
* pdb command line option; -c:           Command-line interface<6>.
                                                             (line   18)
* pdb command line option; -command:     Command-line interface<6>.
                                                             (line   18)
* pdb command line option; -m:           Command-line interface<6>.
                                                             (line   25)
* pdf() (statistics.NormalDist method):  NormalDist objects. (line   74)
* peek() (bz2.BZ2File method):           De compression of files.
                                                             (line   73)
* peek() (gzip.GzipFile method):         gzip — Support for gzip files.
                                                             (line  128)
* peek() (io.BufferedReader method):     Buffered Streams.   (line   73)
* peek() (lzma.LZMAFile method):         Reading and writing compressed files.
                                                             (line   86)
* peek() (weakref.finalize method):      weakref — Weak references.
                                                             (line  305)
* PEM_cert_to_DER_cert() (in module ssl): Certificate handling.
                                                             (line   57)
* pen() (in module turtle):              Drawing state.      (line   33)
* pencolor() (in module turtle):         Color control.      (line    6)
* pending (ssl.MemoryBIO attribute):     Memory BIO support. (line  139)
* pending() (ssl.SSLSocket method):      SSL sockets.        (line  337)
* PendingDeprecationWarning:             Warnings.           (line   28)
* pendown() (in module turtle):          Drawing state.      (line    6)
* pensize() (in module turtle):          Drawing state.      (line   18)
* penup() (in module turtle):            Drawing state.      (line   12)
* PEP:                                   Glossary.           (line 1346)
* per-object lock:                       Glossary.           (line 1299)
* PERCENT (in module token):             token — Constants used with Python parse trees.
                                                             (line  227)
* PERCENTEQUAL (in module token):        token — Constants used with Python parse trees.
                                                             (line  275)
* perf_counter_ns() (in module time):    Functions<5>.       (line  238)
* perf_counter() (in module time):       Functions<5>.       (line  214)
* Performance:                           timeit — Measure execution time of small code snippets.
                                                             (line    8)
* perm() (in module math):               Number-theoretic functions.
                                                             (line   66)
* PermissionError:                       OS exceptions.      (line   97)
* permutations() (in module itertools):  Itertool Functions. (line  436)
* persistence:                           pickle — Python object serialization.
                                                             (line    8)
* persistent_id (pickle protocol):       Persistence of External Objects.
                                                             (line    6)
* persistent_id() (pickle.Pickler method): Module Interface. (line  160)
* persistent_load (pickle protocol):     Persistence of External Objects.
                                                             (line    6)
* persistent_load() (pickle.Unpickler method): Module Interface.
                                                             (line  275)
* persistent; objects:                   pickle — Python object serialization.
                                                             (line    8)
* PF_CAN (in module socket):             Constants<8>.       (line  126)
* PF_DIVERT (in module socket):          Constants<8>.       (line  202)
* PF_PACKET (in module socket):          Constants<8>.       (line  212)
* PF_RDS (in module socket):             Constants<8>.       (line  234)
* pformat() (in module pprint):          Functions<4>.       (line   75)
* pformat() (pprint.PrettyPrinter method): PrettyPrinter Objects.
                                                             (line   50)
* pgettext() (gettext.GNUTranslations method): The GNUTranslations class.
                                                             (line   68)
* pgettext() (gettext.NullTranslations method): The NullTranslations class.
                                                             (line   47)
* pgettext() (in module gettext):        GNU gettext API.    (line   63)
* PGO (in module test.support):          test support — Utilities for the Python test suite.
                                                             (line  107)
* phase() (in module cmath):             Conversions to and from polar coordinates.
                                                             (line   20)
* Philbrick, Geoff:                      Keyword Parameters for Extension Functions.
                                                             (line   25)
* physical line:                         Logical lines.      (line    6)
* physical line <1>:                     Explicit line joining.
                                                             (line    6)
* physical line <2>:                     String and Bytes literals.
                                                             (line   74)
* pi (in module cmath):                  Constants<3>.       (line    6)
* pi (in module math):                   Constants<2>.       (line    6)
* pi() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   56)
* pickle() (in module copyreg):          copyreg — Register pickle support functions.
                                                             (line   23)
* PickleBuffer (class in pickle):        Module Interface.   (line  305)
* PickleError:                           Module Interface.   (line   95)
* Pickler (class in pickle):             Module Interface.   (line  121)
* pickletools command line option; -a:   Command line options<2>.
                                                             (line    6)
* pickletools command line option; -annotate: Command line options<2>.
                                                             (line    6)
* pickletools command line option; -indentlevel: Command line options<2>.
                                                             (line   14)
* pickletools command line option; -l:   Command line options<2>.
                                                             (line   14)
* pickletools command line option; -m:   Command line options<2>.
                                                             (line   18)
* pickletools command line option; -memo: Command line options<2>.
                                                             (line   18)
* pickletools command line option; -o:   Command line options<2>.
                                                             (line   10)
* pickletools command line option; -output: Command line options<2>.
                                                             (line   10)
* pickletools command line option; -p:   Command line options<2>.
                                                             (line   23)
* pickletools command line option; -preamble: Command line options<2>.
                                                             (line   23)
* pickling; objects:                     pickle — Python object serialization.
                                                             (line    8)
* PicklingError:                         Module Interface.   (line  100)
* pid (asyncio.subprocess.Process attribute): Interacting with Subprocesses.
                                                             (line  138)
* pid (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  154)
* pid (subprocess.Popen attribute):      Popen Objects.      (line  149)
* PIDFD_NONBLOCK (in module os):         Process Management. (line  374)
* pidfd_open() (in module os):           Process Management. (line  361)
* pidfd_send_signal() (in module signal): Module contents<3>.
                                                             (line  360)
* PidfdChildWatcher (class in asyncio):  Process Watchers.   (line  156)
* PIP_USER:                              Windows<48>.        (line  102)
* PIPE (in module subprocess):           Using the subprocess Module.
                                                             (line  149)
* PIPE_BUF (in module select):           select — Waiting for I/O completion.
                                                             (line  162)
* pipe_connection_lost() (asyncio.SubprocessProtocol method): Subprocess Protocols.
                                                             (line   19)
* pipe_data_received() (asyncio.SubprocessProtocol method): Subprocess Protocols.
                                                             (line   10)
* PIPE_MAX_SIZE (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  111)
* Pipe() (in module multiprocessing):    Pipes and Queues.   (line   78)
* pipe() (in module os):                 File Descriptor Operations.
                                                             (line  490)
* pipe2() (in module os):                File Descriptor Operations.
                                                             (line  501)
* placeholder (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  274)
* platform (in module sys):              sys — System-specific parameters and functions.
                                                             (line 1379)
* platform (in module sys) <1>:          Process-wide parameters.
                                                             (line  173)
* platform command line option; -nonaliased: Command-line usage<2>.
                                                             (line   19)
* platform command line option; -terse:  Command-line usage<2>.
                                                             (line   13)
* platform() (in module platform):       Cross platform.     (line   48)
* platlibdir (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1444)
* PlaySound() (in module winsound):      winsound — Sound-playing interface for Windows.
                                                             (line   22)
* plist; file:                           plistlib — Generate and parse Apple plist files.
                                                             (line    8)
* plock() (in module os):                Process Management. (line  386)
* plus:                                  Unary arithmetic and bitwise operations.
                                                             (line   14)
* PLUS (in module token):                token — Constants used with Python parse trees.
                                                             (line  197)
* plus() (decimal.Context method):       Context objects.    (line  443)
* PLUSEQUAL (in module token):           token — Constants used with Python parse trees.
                                                             (line  263)
* pm() (in module pdb):                  Command-line interface<6>.
                                                             (line  116)
* POINTER() (in module ctypes):          Utility functions.  (line  181)
* pointer() (in module ctypes):          Utility functions.  (line  187)
* polar() (in module cmath):             Conversions to and from polar coordinates.
                                                             (line   38)
* Policy (class in email.policy):        email policy Policy Objects.
                                                             (line  129)
* poll() (in module select):             select — Waiting for I/O completion.
                                                             (line   89)
* poll() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   42)
* poll() (select.devpoll method):        /dev/poll Polling Objects.
                                                             (line   65)
* poll() (select.epoll method):          Edge and Level Trigger Polling epoll Objects.
                                                             (line   96)
* poll() (select.poll method):           Polling Objects.    (line   77)
* poll() (subprocess.Popen method):      Popen Objects.      (line    8)
* PollSelector (class in selectors):     Classes<4>.         (line  171)
* Pool (class in multiprocessing.pool):  Process Pools.      (line    9)
* pop_all() (contextlib.ExitStack method): Utilities.        (line  593)
* POP_BLOCK (opcode):                    Python Bytecode Instructions.
                                                             (line 1422)
* POP_EXCEPT (opcode):                   Python Bytecode Instructions.
                                                             (line  441)
* POP_JUMP_IF_FALSE (opcode):            Python Bytecode Instructions.
                                                             (line  865)
* POP_JUMP_IF_NONE (opcode):             Python Bytecode Instructions.
                                                             (line  889)
* POP_JUMP_IF_NOT_NONE (opcode):         Python Bytecode Instructions.
                                                             (line  880)
* POP_JUMP_IF_TRUE (opcode):             Python Bytecode Instructions.
                                                             (line  850)
* pop_source() (shlex.shlex method):     shlex Objects.      (line   63)
* POP_TOP (opcode):                      Python Bytecode Instructions.
                                                             (line  139)
* pop() (array.array method):            array — Efficient arrays of numeric values.
                                                             (line  216)
* pop() (collections.deque method):      deque objects.      (line   87)
* pop() (dict method):                   Mapping Types — dict.
                                                             (line  196)
* pop() (mailbox.Mailbox method):        Mailbox objects.    (line  215)
* pop() (sequence method):               Mutable Sequence Types.
                                                             (line  103)
* pop() (set method):                    Set Types — set frozenset.
                                                             (line  210)
* POP3 (class in poplib):                poplib — POP3 protocol client.
                                                             (line   34)
* POP3_SSL (class in poplib):            poplib — POP3 protocol client.
                                                             (line   54)
* POP3; protocol:                        poplib — POP3 protocol client.
                                                             (line    8)
* Popen (class in subprocess):           Popen Constructor.  (line   11)
* popen() (in module os):                I/O objects also known as file objects.
                                                             (line    6)
* popen() (in module os) <1>:            Process Management. (line  393)
* popen() (in module os) <2>:            select — Waiting for I/O completion.
                                                             (line  143)
* popitem() (collections.OrderedDict method): OrderedDict objects.
                                                             (line   71)
* popitem() (dict method):               Mapping Types — dict.
                                                             (line  204)
* popitem() (mailbox.Mailbox method):    Mailbox objects.    (line  224)
* popleft() (collections.deque method):  deque objects.      (line   92)
* port (http.cookiejar.Cookie attribute): Cookie Objects<2>. (line   35)
* port_specified (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   79)
* portion:                               Glossary.           (line 1362)
* pos (json.JSONDecodeError attribute):  Exceptions<17>.     (line   19)
* pos (re.Match attribute):              Match Objects.      (line  178)
* pos (re.PatternError attribute):       Exceptions<3>.      (line   23)
* pos() (in module operator):            operator — Standard operators as functions.
                                                             (line  142)
* pos() (in module turtle):              Tell Turtle’s state.
                                                             (line    6)
* position (xml.etree.ElementTree.ParseError attribute): Exceptions<19>.
                                                             (line   20)
* position() (in module turtle):         Tell Turtle’s state.
                                                             (line    6)
* positional argument:                   Glossary.           (line 1368)
* Positions (class in dis):              Python Bytecode Instructions.
                                                             (line  110)
* positions (inspect.FrameInfo attribute): The interpreter stack.
                                                             (line   42)
* positions (inspect.Traceback attribute): The interpreter stack.
                                                             (line   82)
* Positions.col_offset (in module dis):  Python Bytecode Instructions.
                                                             (line  119)
* Positions.end_col_offset (in module dis): Python Bytecode Instructions.
                                                             (line  121)
* Positions.end_lineno (in module dis):  Python Bytecode Instructions.
                                                             (line  117)
* Positions.lineno (in module dis):      Python Bytecode Instructions.
                                                             (line  115)
* POSIX Shared Memory:                   multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line   10)
* POSIX_FADV_DONTNEED (in module os):    File Descriptor Operations.
                                                             (line  535)
* POSIX_FADV_NOREUSE (in module os):     File Descriptor Operations.
                                                             (line  535)
* POSIX_FADV_NORMAL (in module os):      File Descriptor Operations.
                                                             (line  535)
* POSIX_FADV_RANDOM (in module os):      File Descriptor Operations.
                                                             (line  535)
* POSIX_FADV_SEQUENTIAL (in module os):  File Descriptor Operations.
                                                             (line  535)
* POSIX_FADV_WILLNEED (in module os):    File Descriptor Operations.
                                                             (line  535)
* posix_fadvise() (in module os):        File Descriptor Operations.
                                                             (line  521)
* posix_fallocate() (in module os):      File Descriptor Operations.
                                                             (line  512)
* posix_openpt() (in module os):         File Descriptor Operations.
                                                             (line  562)
* POSIX_SPAWN_CLOSE (in module os):      Process Management. (line  459)
* POSIX_SPAWN_CLOSEFROM (in module os):  Process Management. (line  471)
* POSIX_SPAWN_DUP2 (in module os):       Process Management. (line  465)
* POSIX_SPAWN_OPEN (in module os):       Process Management. (line  453)
* posix_spawn() (in module os):          Process Management. (line  430)
* posix_spawnp() (in module os):         Process Management. (line  532)
* POSIX; I/O control:                    termios — POSIX style tty control.
                                                             (line    6)
* PosixPath (class in pathlib):          Concrete paths.     (line   22)
* post_handshake_auth (ssl.SSLContext attribute): SSL contexts.
                                                             (line  588)
* post_mortem() (in module pdb):         Command-line interface<6>.
                                                             (line  107)
* post_setup() (venv.EnvBuilder method): API<2>.             (line  177)
* postcmd() (cmd.Cmd method):            Cmd Objects.        (line  103)
* postloop() (cmd.Cmd method):           Cmd Objects.        (line  121)
* Pow (class in ast):                    Expressions<2>.     (line   53)
* pow() (in module math):                Power exponential and logarithmic functions.
                                                             (line   72)
* pow() (in module operator):            operator — Standard operators as functions.
                                                             (line  147)
* power; operation:                      The power operator. (line    6)
* power() (decimal.Context method):      Context objects.    (line  449)
* pp (pdb command):                      Debugger commands.  (line  275)
* pp() (in module pprint):               Functions<4>.       (line    6)
* pprint() (in module pprint):           Functions<4>.       (line   67)
* pprint() (pprint.PrettyPrinter method): PrettyPrinter Objects.
                                                             (line   56)
* prcal() (in module calendar):          calendar — General calendar-related functions.
                                                             (line  406)
* pread() (in module os):                File Descriptor Operations.
                                                             (line  549)
* preadv() (in module os):               File Descriptor Operations.
                                                             (line  580)
* preamble (email.message.EmailMessage attribute): email message Representing an email message.
                                                             (line  679)
* preamble (email.message.Message attribute): email message Message Representing an email message using the compat32 API.
                                                             (line  691)
* prec (decimal.Context attribute):      Context objects.    (line  123)
* precmd() (cmd.Cmd method):             Cmd Objects.        (line   93)
* prefix (in module sys):                sys — System-specific parameters and functions.
                                                             (line 1469)
* prefix (xml.dom.Attr attribute):       Attr Objects.       (line   18)
* prefix (xml.dom.Node attribute):       Node Objects.       (line   69)
* prefix (zipimport.zipimporter attribute): zipimporter Objects.
                                                             (line  101)
* PREFIXES (in module site):             Module contents<6>. (line    6)
* prefixlen (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  132)
* prefixlen (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  329)
* preloop() (cmd.Cmd method):            Cmd Objects.        (line  115)
* prepare_class() (in module types):     Dynamic Type Creation.
                                                             (line   23)
* prepare_input_source() (in module xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   81)
* prepare() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line  100)
* prepare() (logging.handlers.QueueHandler method): QueueHandler.
                                                             (line   52)
* prepare() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   57)
* PrepareProtocol (class in sqlite3):    PrepareProtocol objects.
                                                             (line    6)
* PrettyPrinter (class in pprint):       PrettyPrinter Objects.
                                                             (line    6)
* prev() (tkinter.ttk.Treeview method):  ttk Treeview.       (line  232)
* previousSibling (xml.dom.Node attribute): Node Objects.    (line   32)
* primary:                               Primaries.          (line    6)
* print_callees() (pstats.Stats method): The Stats Class.    (line  216)
* print_callers() (pstats.Stats method): The Stats Class.    (line  195)
* print_exc() (in module traceback):     Module-Level Functions<2>.
                                                             (line   58)
* print_exc() (timeit.Timer method):     Python Interface.   (line  134)
* print_exception() (in module traceback): Module-Level Functions<2>.
                                                             (line   24)
* print_function (in module __future__): Module Contents<4>. (line   35)
* print_help() (argparse.ArgumentParser method): Printing help.
                                                             (line   16)
* print_last() (in module traceback):    Module-Level Functions<2>.
                                                             (line   63)
* print_list() (in module traceback):    Module-Level Functions<2>.
                                                             (line  101)
* print_stack() (asyncio.Task method):   Task object.        (line  143)
* print_stack() (in module traceback):   Module-Level Functions<2>.
                                                             (line   70)
* print_stats() (profile.Profile method): profile and cProfile Module Reference.
                                                             (line   91)
* print_stats() (pstats.Stats method):   The Stats Class.    (line  164)
* print_tb() (in module traceback):      Module-Level Functions<2>.
                                                             (line    6)
* print_usage() (argparse.ArgumentParser method): Printing help.
                                                             (line   10)
* print_usage() (optparse.OptionParser method): Other methods.
                                                             (line   15)
* print_version() (optparse.OptionParser method): Printing a version string.
                                                             (line   26)
* print_warning() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  415)
* print() (built-in function); __str__() (object method): Basic customization.
                                                             (line  129)
* print() (traceback.TracebackException method): TracebackException Objects.
                                                             (line  136)
* printable (in module string):          String constants.   (line   41)
* printdir() (zipfile.ZipFile method):   ZipFile objects.    (line  235)
* printf-style formatting:               printf-style String Formatting.
                                                             (line    6)
* printf-style formatting <1>:           printf-style Bytes Formatting.
                                                             (line    6)
* PRIO_DARWIN_BG (in module os):         Process Parameters. (line  297)
* PRIO_DARWIN_NONUI (in module os):      Process Parameters. (line  297)
* PRIO_DARWIN_PROCESS (in module os):    Process Parameters. (line  297)
* PRIO_DARWIN_THREAD (in module os):     Process Parameters. (line  297)
* PRIO_PGRP (in module os):              Process Parameters. (line  286)
* PRIO_PROCESS (in module os):           Process Parameters. (line  286)
* PRIO_USER (in module os):              Process Parameters. (line  286)
* PriorityQueue (class in asyncio):      Priority Queue.     (line    6)
* PriorityQueue (class in queue):        queue — A synchronized queue class.
                                                             (line   48)
* private; names:                        Identifiers Names.  (line   14)
* prlimit() (in module resource):        Resource Limits.    (line   55)
* prmonth() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  202)
* prmonth() (in module calendar):        calendar — General calendar-related functions.
                                                             (line  397)
* ProactorEventLoop (class in asyncio):  Event loop implementations.
                                                             (line   32)
* procedure; call:                       Expression statements.
                                                             (line   17)
* Process (class in multiprocessing):    Process and exceptions.
                                                             (line    6)
* process_cpu_count() (in module os):    Miscellaneous System Information.
                                                             (line   60)
* process_exited() (asyncio.SubprocessProtocol method): Subprocess Protocols.
                                                             (line   26)
* process_request() (socketserver.BaseServer method): Server Objects.
                                                             (line  159)
* process_time_ns() (in module time):    Functions<5>.       (line  258)
* process_time() (in module time):       Functions<5>.       (line  245)
* process_tokens() (in module tabnanny): tabnanny — Detection of ambiguous indentation.
                                                             (line   42)
* process; group:                        Process Parameters. (line  188)
* process; group <1>:                    Process Parameters. (line  250)
* process; id:                           Process Parameters. (line  256)
* process; id of parent:                 Process Parameters. (line  263)
* process; killing:                      Process Management. (line  325)
* process; killing <1>:                  Process Management. (line  347)
* process; scheduling priority:          Process Parameters. (line  274)
* process; scheduling priority <1>:      Process Parameters. (line  460)
* process; signalling:                   Process Management. (line  325)
* process; signalling <1>:               Process Management. (line  347)
* process() (logging.LoggerAdapter method): LoggerAdapter Objects.
                                                             (line   21)
* ProcessError:                          Process and exceptions.
                                                             (line  260)
* processes, light-weight:               _thread — Low-level threading API.
                                                             (line    6)
* ProcessingInstruction() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  183)
* processingInstruction() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  161)
* ProcessingInstructionHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  323)
* ProcessLookupError:                    OS exceptions.      (line  107)
* processor time:                        Functions<5>.       (line  247)
* processor time <1>:                    Functions<5>.       (line  615)
* processor() (in module platform):      Cross platform.     (line   69)
* ProcessPoolExecutor (class in concurrent.futures): ProcessPoolExecutor.
                                                             (line   26)
* prod() (in module math):               Summation and product functions.
                                                             (line   51)
* product() (in module itertools):       Itertool Functions. (line  488)
* Profile (class in profile):            profile and cProfile Module Reference.
                                                             (line   35)
* profile function:                      Reference<2>.       (line  138)
* profile function <1>:                  Reference<2>.       (line  154)
* profile function <2>:                  sys — System-specific parameters and functions.
                                                             (line  938)
* profile function <3>:                  sys — System-specific parameters and functions.
                                                             (line 1516)
* PROFILE_TASK:                          Build<21>.          (line   13)
* PROFILE_TASK <1>:                      Performance options.
                                                             (line   12)
* profiler:                              sys — System-specific parameters and functions.
                                                             (line  938)
* profiler <1>:                          sys — System-specific parameters and functions.
                                                             (line 1516)
* profiling, deterministic:              Introduction to the profilers.
                                                             (line    6)
* program:                               Complete Python programs.
                                                             (line    6)
* ProgrammingError:                      Exceptions<7>.      (line   78)
* Progressbar (class in tkinter.ttk):    ttk Progressbar.    (line    6)
* prompt (cmd.Cmd attribute):            Cmd Objects.        (line  130)
* prompt_user_passwd() (urllib.request.FancyURLopener method): Legacy interface.
                                                             (line  182)
* prompts, interpreter:                  sys — System-specific parameters and functions.
                                                             (line 1485)
* propagate (logging.Logger attribute):  Logger Objects.     (line   50)
* property (built-in class):             Built-in Functions. (line 1586)
* property list:                         plistlib — Generate and parse Apple plist files.
                                                             (line    8)
* property_declaration_handler (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  111)
* property_dom_node (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  118)
* property_lexical_handler (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  104)
* property_xml_string (in module xml.sax.handler): xml sax handler — Base classes for SAX handlers.
                                                             (line  125)
* property() (in module enum):           Utilities and decorators.
                                                             (line   39)
* PropertyMock (class in unittest.mock): The Mock Class.     (line  648)
* prot_c() (ftplib.FTP_TLS method):      FTP_TLS objects.    (line  110)
* prot_p() (ftplib.FTP_TLS method):      FTP_TLS objects.    (line  106)
* proto (socket.socket attribute):       Socket Objects.     (line  619)
* Protocol (class in asyncio):           Base Protocols.     (line   10)
* Protocol (class in typing):            Other special directives.
                                                             (line  135)
* protocol (ssl.SSLContext attribute):   SSL contexts.       (line  607)
* PROTOCOL_SSLv23 (in module ssl):       Constants<9>.       (line  161)
* PROTOCOL_SSLv3 (in module ssl):        Constants<9>.       (line  168)
* PROTOCOL_TLS (in module ssl):          Constants<9>.       (line  131)
* PROTOCOL_TLS_CLIENT (in module ssl):   Constants<9>.       (line  144)
* PROTOCOL_TLS_SERVER (in module ssl):   Constants<9>.       (line  153)
* PROTOCOL_TLSv1 (in module ssl):        Constants<9>.       (line  184)
* PROTOCOL_TLSv1_1 (in module ssl):      Constants<9>.       (line  191)
* PROTOCOL_TLSv1_2 (in module ssl):      Constants<9>.       (line  201)
* protocol_version (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  161)
* PROTOCOL_VERSION (imaplib.IMAP4 attribute): IMAP4 Objects. (line  395)
* protocol; context management:          Context Manager Types.
                                                             (line    6)
* protocol; iterator:                    Iterator Types.     (line    6)
* ProtocolError (class in xmlrpc.client): ProtocolError Objects.
                                                             (line    6)
* provisional API:                       Glossary.           (line 1372)
* provisional package:                   Glossary.           (line 1392)
* proxy() (in module weakref):           weakref — Weak references.
                                                             (line  134)
* proxyauth() (imaplib.IMAP4 method):    IMAP4 Objects.      (line  197)
* ProxyBasicAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  370)
* ProxyDigestAuthHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  402)
* ProxyHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  296)
* ProxyType (in module weakref):         weakref — Weak references.
                                                             (line  334)
* ProxyTypes (in module weakref):        weakref — Weak references.
                                                             (line  342)
* pryear() (calendar.TextCalendar method): calendar — General calendar-related functions.
                                                             (line  217)
* ps1 (in module sys):                   sys — System-specific parameters and functions.
                                                             (line 1482)
* ps2 (in module sys):                   sys — System-specific parameters and functions.
                                                             (line 1482)
* pstdev() (in module statistics):       Function details.   (line  371)
* pthread_getcpuclockid() (in module time): Functions<5>.    (line   21)
* pthread_kill() (in module signal):     Module contents<3>. (line  375)
* pthread_sigmask() (in module signal):  Module contents<3>. (line  405)
* pthreads:                              _thread — Low-level threading API.
                                                             (line   16)
* pthreads (sys._emscripten_info attribute): sys — System-specific parameters and functions.
                                                             (line  359)
* ptsname() (in module os):              File Descriptor Operations.
                                                             (line  639)
* pu() (in module turtle):               Drawing state.      (line   12)
* publicId (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   17)
* PullDOM (class in xml.dom.pulldom):    xml dom pulldom — Support for building partial DOM trees.
                                                             (line   76)
* punctuation (in module string):        String constants.   (line   36)
* punctuation_chars (shlex.shlex attribute): shlex Objects.  (line  183)
* PurePath (class in pathlib):           Pure paths.         (line   10)
* PurePosixPath (class in pathlib):      Pure paths.         (line   72)
* PureWindowsPath (class in pathlib):    Pure paths.         (line   82)
* purge() (in module re):                Functions<2>.       (line  289)
* Purpose.CLIENT_AUTH (in module ssl):   Constants<9>.       (line  540)
* Purpose.SERVER_AUTH (in module ssl):   Constants<9>.       (line  531)
* push_async_callback() (contextlib.AsyncExitStack method): Utilities.
                                                             (line  644)
* push_async_exit() (contextlib.AsyncExitStack method): Utilities.
                                                             (line  639)
* PUSH_EXC_INFO (opcode):                Python Bytecode Instructions.
                                                             (line  460)
* PUSH_NULL (opcode):                    Python Bytecode Instructions.
                                                             (line 1102)
* push_source() (shlex.shlex method):    shlex Objects.      (line   56)
* push_token() (shlex.shlex method):     shlex Objects.      (line   16)
* push() (code.InteractiveConsole method): Interactive Console Objects.
                                                             (line   28)
* push() (contextlib.ExitStack method):  Utilities.          (line  560)
* put_nowait() (asyncio.Queue method):   Queue.              (line   72)
* put_nowait() (multiprocessing.Queue method): Pipes and Queues.
                                                             (line  149)
* put_nowait() (queue.Queue method):     Queue Objects.      (line   42)
* put_nowait() (queue.SimpleQueue method): SimpleQueue Objects.
                                                             (line   35)
* put() (asyncio.Queue method):          Queue.              (line   64)
* put() (multiprocessing.Queue method):  Pipes and Queues.   (line  133)
* put() (multiprocessing.SimpleQueue method): Pipes and Queues.
                                                             (line  251)
* put() (queue.Queue method):            Queue Objects.      (line   29)
* put() (queue.SimpleQueue method):      SimpleQueue Objects.
                                                             (line   20)
* putch() (in module msvcrt):            Console I/O.        (line   36)
* putenv() (in module os):               Process Parameters. (line  346)
* putheader() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  182)
* putp() (in module curses):             Functions<6>.       (line  391)
* putrequest() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  171)
* putwch() (in module msvcrt):           Console I/O.        (line   40)
* putwin() (curses.window method):       Window Objects.     (line  457)
* pvariance() (in module statistics):    Function details.   (line  380)
* pwd() (ftplib.FTP method):             FTP objects.        (line  343)
* pwrite() (in module os):               File Descriptor Operations.
                                                             (line  653)
* pwritev() (in module os):              File Descriptor Operations.
                                                             (line  664)
* Py_ABS (C macro):                      Useful macros.      (line   34)
* Py_AddPendingCall (C function):        Asynchronous Notifications.
                                                             (line   10)
* Py_ALIGNED (C macro):                  Useful macros.      (line   43)
* Py_ALWAYS_INLINE (C macro):            Useful macros.      (line   71)
* Py_am_aiter (C macro):                 Async Object Structures.
                                                             (line   41)
* Py_am_anext (C macro):                 Async Object Structures.
                                                             (line   56)
* Py_am_await (C macro):                 Async Object Structures.
                                                             (line   26)
* Py_am_send (C macro):                  Async Object Structures.
                                                             (line   68)
* Py_ARITHMETIC_RIGHT_SHIFT (C macro):   Useful macros.      (line   50)
* Py_ARRAY_LENGTH (C macro):             Useful macros.      (line  339)
* Py_ASNATIVEBYTES_ALLOW_INDEX (C macro): Integer Objects.   (line  481)
* Py_ASNATIVEBYTES_BIG_ENDIAN (C macro): Integer Objects.    (line  466)
* Py_ASNATIVEBYTES_DEFAULTS (C macro):   Integer Objects.    (line  463)
* Py_ASNATIVEBYTES_LITTLE_ENDIAN (C macro): Integer Objects. (line  469)
* Py_ASNATIVEBYTES_NATIVE_ENDIAN (C macro): Integer Objects. (line  472)
* Py_ASNATIVEBYTES_REJECT_NEGATIVE (C macro): Integer Objects.
                                                             (line  478)
* Py_ASNATIVEBYTES_UNSIGNED_BUFFER (C macro): Integer Objects.
                                                             (line  475)
* Py_AtExit (C function):                Process Control.    (line   32)
* Py_AUDIT_READ (C macro):               Member flags.       (line   12)
* Py_AuditHookFunction (C type):         System Functions.   (line  150)
* Py_BEGIN_ALLOW_THREADS (C macro):      Releasing the GIL from extension code.
                                                             (line   21)
* Py_BEGIN_ALLOW_THREADS (C macro) <1>:  High-level API.     (line  187)
* Py_BEGIN_CRITICAL_SECTION (C macro):   Python Critical Section API.
                                                             (line   57)
* Py_BEGIN_CRITICAL_SECTION2 (C macro):  Python Critical Section API.
                                                             (line   85)
* Py_bf_getbuffer (C macro):             Buffer Object Structures.
                                                             (line   16)
* Py_bf_releasebuffer (C macro):         Buffer Object Structures.
                                                             (line   67)
* Py_BLOCK_THREADS (C macro):            High-level API.     (line  201)
* Py_buffer (C type):                    Buffer structure.   (line   25)
* Py_buffer.buf (C member):              Buffer structure.   (line   27)
* Py_buffer.format (C member):           Buffer structure.   (line   89)
* Py_buffer.internal (C member):         Buffer structure.   (line  152)
* Py_buffer.itemsize (C member):         Buffer structure.   (line   69)
* Py_buffer.len (C member):              Buffer structure.   (line   52)
* Py_buffer.ndim (C member):             Buffer structure.   (line   98)
* Py_buffer.obj (C member):              Buffer structure.   (line   39)
* Py_buffer.readonly (C member):         Buffer structure.   (line   64)
* Py_buffer.shape (C member):            Buffer structure.   (line  107)
* Py_buffer.strides (C member):          Buffer structure.   (line  120)
* Py_buffer.suboffsets (C member):       Buffer structure.   (line  133)
* Py_BUILD_ASSERT (C macro):             Useful macros.      (line  270)
* Py_BUILD_ASSERT_EXPR (C macro):        Useful macros.      (line  282)
* Py_BuildValue (C function):            Building values.    (line    6)
* Py_BytesMain (C function):             Initializing and finalizing the interpreter.
                                                             (line  119)
* Py_BytesWarningFlag (C var):           Global configuration variables.
                                                             (line   15)
* Py_CAN_START_THREADS (C macro):        Useful macros.      (line   96)
* Py_CHARMASK (C macro):                 Useful macros.      (line  107)
* Py_CLEANUP_SUPPORTED (C macro):        Other objects.      (line   40)
* Py_CLEAR (C function):                 Reference Counting. (line  144)
* Py_CompileString (C function):         The Very High Level Layer.
                                                             (line  229)
* Py_CompileString (C function) <1>:     Available start symbols.
                                                             (line    8)
* Py_CompileString (C function) <2>:     Available start symbols.
                                                             (line   13)
* Py_CompileString (C function) <3>:     Available start symbols.
                                                             (line   20)
* Py_CompileString (C function) <4>:     Available start symbols.
                                                             (line   26)
* Py_CompileStringExFlags (C function):  The Very High Level Layer.
                                                             (line  262)
* Py_CompileStringFlags (C function):    The Very High Level Layer.
                                                             (line  236)
* Py_CompileStringObject (C function):   The Very High Level Layer.
                                                             (line  242)
* Py_complex (C type):                   Complex Numbers as C Structures.
                                                             (line   10)
* Py_complex.imag (C member):            Complex Numbers as C Structures.
                                                             (line   17)
* Py_complex.real (C member):            Complex Numbers as C Structures.
                                                             (line   17)
* Py_CONSTANT_ELLIPSIS (C macro):        Object Protocol.    (line   28)
* Py_CONSTANT_EMPTY_BYTES (C macro):     Object Protocol.    (line   43)
* Py_CONSTANT_EMPTY_STR (C macro):       Object Protocol.    (line   40)
* Py_CONSTANT_EMPTY_TUPLE (C macro):     Object Protocol.    (line   46)
* Py_CONSTANT_FALSE (C macro):           Object Protocol.    (line   22)
* Py_CONSTANT_NONE (C macro):            Object Protocol.    (line   19)
* Py_CONSTANT_NOT_IMPLEMENTED (C macro): Object Protocol.    (line   31)
* Py_CONSTANT_ONE (C macro):             Object Protocol.    (line   37)
* Py_CONSTANT_TRUE (C macro):            Object Protocol.    (line   25)
* Py_CONSTANT_ZERO (C macro):            Object Protocol.    (line   34)
* PY_CXX_CONST (C macro):                API Functions.      (line  115)
* Py_DEBUG (C macro):                    Debugging Builds.   (line   17)
* Py_DEBUG (in module test.support):     test support — Utilities for the Python test suite.
                                                             (line  116)
* Py_DebugFlag (C var):                  Global configuration variables.
                                                             (line   29)
* Py_DecodeLocale (C function):          Operating System Utilities.
                                                             (line  131)
* Py_DECREF (C function):                Reference Counts<2>.
                                                             (line   18)
* Py_DECREF (C function) <1>:            Reference Counting. (line  104)
* Py_DecRef (C function):                Reference Counting. (line  167)
* Py_DEPRECATED (C macro):               Useful macros.      (line  112)
* Py_DontWriteBytecodeFlag (C var):      Global configuration variables.
                                                             (line   43)
* Py_DTSF_ADD_DOT_0 (C macro):           String conversion and formatting.
                                                             (line  135)
* Py_DTSF_ALT (C macro):                 String conversion and formatting.
                                                             (line  139)
* Py_DTSF_NO_NEG_0 (C macro):            String conversion and formatting.
                                                             (line  144)
* Py_DTSF_SIGN (C macro):                String conversion and formatting.
                                                             (line  130)
* Py_DTST_FINITE (C macro):              String conversion and formatting.
                                                             (line  157)
* Py_DTST_INFINITE (C macro):            String conversion and formatting.
                                                             (line  160)
* Py_DTST_NAN (C macro):                 String conversion and formatting.
                                                             (line  163)
* Py_Ellipsis (C var):                   Ellipsis Object.    (line   11)
* Py_EncodeLocale (C function):          Operating System Utilities.
                                                             (line  184)
* Py_END_ALLOW_THREADS (C macro):        Releasing the GIL from extension code.
                                                             (line   21)
* Py_END_ALLOW_THREADS (C macro) <1>:    High-level API.     (line  194)
* Py_END_CRITICAL_SECTION (C macro):     Python Critical Section API.
                                                             (line   72)
* Py_END_CRITICAL_SECTION2 (C macro):    Python Critical Section API.
                                                             (line  101)
* Py_EndInterpreter (C function):        Sub-interpreter support.
                                                             (line  206)
* Py_EnterRecursiveCall (C function):    Recursion Control.  (line   13)
* Py_EQ (C macro):                       PyTypeObject Slots. (line 1155)
* Py_eval_input (C var):                 Available start symbols.
                                                             (line    6)
* Py_Exit (C function):                  Process Control.    (line   22)
* Py_ExitStatusException (C function):   PyStatus.           (line   65)
* Py_EXPORTED_SYMBOL (C macro):          Useful macros.      (line  353)
* Py_False (C var):                      Boolean Objects.    (line   21)
* Py_FatalError (C function):            Process Control.    (line    6)
* Py_FatalError():                       Process-wide parameters.
                                                             (line  218)
* Py_FdIsInteractive (C function):       Operating System Utilities.
                                                             (line   18)
* Py_file_input (C var):                 Available start symbols.
                                                             (line   11)
* Py_Finalize (C function):              Initializing and finalizing the interpreter.
                                                             (line  114)
* Py_FinalizeEx (C function):            Process Control.    (line   23)
* Py_FinalizeEx (C function) <1>:        Process Control.    (line   33)
* Py_FinalizeEx (C function) <2>:        Initializing and finalizing the interpreter.
                                                             (line    7)
* Py_FinalizeEx (C function) <3>:        Initializing and finalizing the interpreter.
                                                             (line   64)
* Py_FinalizeEx (C function) <4>:        Sub-interpreter support.
                                                             (line  169)
* Py_FinalizeEx (C function) <5>:        Sub-interpreter support.
                                                             (line  207)
* Py_FORCE_EXPANSION (C macro):          Useful macros.      (line  123)
* Py_FrozenFlag (C var):                 Global configuration variables.
                                                             (line   57)
* Py_func_type_input (C var):            Available start symbols.
                                                             (line   24)
* Py_GCC_ATTRIBUTE (C macro):            Useful macros.      (line  129)
* Py_GE (C macro):                       PyTypeObject Slots. (line 1164)
* Py_GenericAlias (C function):          Objects for Type Hinting.
                                                             (line   10)
* Py_GenericAliasType (C var):           Objects for Type Hinting.
                                                             (line   42)
* Py_GetArgcArgv (C function):           Py_GetArgcArgv.     (line    6)
* Py_GetBuildInfo (C function):          Process-wide parameters.
                                                             (line  205)
* Py_GetCompiler (C function):           Process-wide parameters.
                                                             (line  194)
* Py_GetConstant (C function):           Object Protocol.    (line    6)
* Py_GetConstantBorrowed (C function):   Object Protocol.    (line   57)
* Py_GetCopyright (C function):          Process-wide parameters.
                                                             (line  184)
* Py_GETENV (C macro):                   Useful macros.      (line  137)
* Py_GetExecPrefix (C function):         Embedding Python<2>.
                                                             (line   42)
* Py_GetExecPrefix (C function) <1>:     Process-wide parameters.
                                                             (line   68)
* Py_GetPath (C function):               Embedding Python<2>.
                                                             (line   42)
* Py_GetPath (C function) <1>:           Process-wide parameters.
                                                             (line  135)
* Py_GetPath():                          Process-wide parameters.
                                                             (line    7)
* Py_GetPlatform (C function):           Process-wide parameters.
                                                             (line  172)
* Py_GetPrefix (C function):             Embedding Python<2>.
                                                             (line   42)
* Py_GetPrefix (C function) <1>:         Process-wide parameters.
                                                             (line   45)
* Py_GetProgramFullPath (C function):    Embedding Python<2>.
                                                             (line   42)
* Py_GetProgramFullPath (C function) <1>: Process-wide parameters.
                                                             (line  116)
* Py_GetProgramName (C function):        Process-wide parameters.
                                                             (line   30)
* Py_GetPythonHome (C function):         Process-wide parameters.
                                                             (line  308)
* Py_GetRecursionLimit (C function):     Recursion Control.  (line   69)
* Py_GetVersion (C function):            Process-wide parameters.
                                                             (line  158)
* Py_GT (C macro):                       PyTypeObject Slots. (line 1161)
* Py_HASH_ALGORITHM (C macro):           PyHash API.         (line   21)
* Py_HASH_CUTOFF (C macro):              PyHash API.         (line   44)
* Py_HASH_FNV (C macro):                 PyHash API.         (line   31)
* Py_HASH_SIPHASH13 (C macro):           PyHash API.         (line   31)
* Py_HASH_SIPHASH24 (C macro):           PyHash API.         (line   31)
* Py_hash_t (C type):                    PyHash API.         (line    9)
* Py_HashPointer (C function):           PyHash API.         (line  144)
* Py_HashRandomizationFlag (C var):      Global configuration variables.
                                                             (line   70)
* PY_HAVE_THREAD_NATIVE_ID (C macro):    Operating System Thread APIs.
                                                             (line   49)
* Py_hexdigits (C var):                  Codec utility variables.
                                                             (line    6)
* Py_HUGE_VAL (C macro):                 Floating-Point Objects.
                                                             (line   83)
* Py_IgnoreEnvironmentFlag (C var):      Global configuration variables.
                                                             (line   85)
* Py_IMPORTED_SYMBOL (C macro):          Useful macros.      (line  361)
* Py_INCREF (C function):                Reference Counts<2>.
                                                             (line   18)
* Py_INCREF (C function) <1>:            Reference Counting. (line   42)
* Py_IncRef (C function):                Reference Counting. (line  161)
* Py_INFINITY (C macro):                 Floating-Point Objects.
                                                             (line   67)
* Py_Initialize (C function):            Embedding Python<2>.
                                                             (line   12)
* Py_Initialize (C function) <1>:        Initializing and finalizing the interpreter.
                                                             (line    6)
* Py_Initialize (C function) <2>:        Sub-interpreter support.
                                                             (line  169)
* Py_Initialize():                       Process-wide parameters.
                                                             (line    7)
* Py_InitializeEx (C function):          Initializing and finalizing the interpreter.
                                                             (line   30)
* Py_InitializeFromConfig (C function):  Initializing and finalizing the interpreter.
                                                             (line   40)
* Py_InspectFlag (C var):                Global configuration variables.
                                                             (line   98)
* Py_InteractiveFlag (C var):            Global configuration variables.
                                                             (line  114)
* PY_INVALID_STACK_EFFECT (C macro):     Stack Effects.      (line   11)
* Py_Is (C function):                    Base object types and macros.
                                                             (line   59)
* Py_IS_FINITE (C macro):                Floating-Point Objects.
                                                             (line  132)
* Py_IS_INFINITY (C macro):              Floating-Point Objects.
                                                             (line  141)
* Py_IS_NAN (C macro):                   Floating-Point Objects.
                                                             (line  149)
* Py_IS_TYPE (C function):               Base object types and macros.
                                                             (line   98)
* Py_ISALNUM (C macro):                  Character classification and conversion.
                                                             (line   10)
* Py_ISALPHA (C macro):                  Character classification and conversion.
                                                             (line   14)
* Py_ISDIGIT (C macro):                  Character classification and conversion.
                                                             (line   19)
* Py_IsFalse (C function):               Base object types and macros.
                                                             (line   79)
* Py_IsFinalizing (C function):          Initializing and finalizing the interpreter.
                                                             (line   57)
* Py_IsInitialized (C function):         Embedding Python<2>.
                                                             (line   51)
* Py_IsInitialized (C function) <1>:     Initializing and finalizing the interpreter.
                                                             (line   51)
* Py_ISLOWER (C macro):                  Character classification and conversion.
                                                             (line   23)
* Py_IsNone (C function):                Base object types and macros.
                                                             (line   65)
* Py_IsolatedFlag (C var):               Global configuration variables.
                                                             (line  124)
* Py_ISSPACE (C macro):                  Character classification and conversion.
                                                             (line   33)
* Py_IsTrue (C function):                Base object types and macros.
                                                             (line   72)
* Py_ISUPPER (C macro):                  Character classification and conversion.
                                                             (line   28)
* Py_ISXDIGIT (C macro):                 Character classification and conversion.
                                                             (line   38)
* Py_LE (C macro):                       PyTypeObject Slots. (line 1152)
* Py_LeaveRecursiveCall (C function):    Recursion Control.  (line   33)
* Py_LegacyWindowsFSEncodingFlag (C var): Global configuration variables.
                                                             (line  140)
* Py_LegacyWindowsStdioFlag (C var):     Global configuration variables.
                                                             (line  160)
* Py_LIMITED_API (C macro):              Limited C API.      (line   11)
* Py_LL (C macro):                       Useful macros.      (line  142)
* Py_LOCAL (C macro):                    Useful macros.      (line  153)
* Py_LOCAL_INLINE (C macro):             Useful macros.      (line  159)
* Py_LOCAL_SYMBOL (C macro):             Useful macros.      (line  164)
* PY_LOCK_ACQUIRED (C enumerator):       Legacy Locking APIs.
                                                             (line   24)
* PY_LOCK_FAILURE (C enumerator):        Legacy Locking APIs.
                                                             (line   20)
* PY_LOCK_INTR (C enumerator):           Legacy Locking APIs.
                                                             (line   28)
* Py_LT (C macro):                       PyTypeObject Slots. (line 1149)
* Py_Main (C function):                  Initializing and finalizing the interpreter.
                                                             (line  127)
* PY_MAJOR_VERSION (C macro):            API and ABI Versioning.
                                                             (line   13)
* Py_MakePendingCalls (C function):      Asynchronous Notifications.
                                                             (line   58)
* Py_MATH_E (C macro):                   Floating-Point Objects.
                                                             (line   90)
* Py_MATH_El (C macro):                  Floating-Point Objects.
                                                             (line   95)
* Py_MATH_PI (C macro):                  Floating-Point Objects.
                                                             (line   99)
* Py_MATH_PIl (C macro):                 Floating-Point Objects.
                                                             (line  104)
* Py_MATH_TAU (C macro):                 Floating-Point Objects.
                                                             (line  109)
* Py_MAX (C macro):                      Useful macros.      (line  173)
* Py_MEMBER_SIZE (C macro):              Useful macros.      (line  179)
* PY_MICRO_VERSION (C macro):            API and ABI Versioning.
                                                             (line   21)
* Py_MIN (C macro):                      Useful macros.      (line  185)
* PY_MINOR_VERSION (C macro):            API and ABI Versioning.
                                                             (line   17)
* Py_mod_create (C macro):               Multi-phase initialization.
                                                             (line   78)
* Py_mod_exec (C macro):                 Multi-phase initialization.
                                                             (line  114)
* Py_mod_gil (C macro):                  Multi-phase initialization.
                                                             (line  159)
* Py_MOD_GIL_NOT_USED (C macro):         Multi-phase initialization.
                                                             (line  169)
* Py_MOD_GIL_USED (C macro):             Multi-phase initialization.
                                                             (line  163)
* Py_mod_multiple_interpreters (C macro): Multi-phase initialization.
                                                             (line  128)
* Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED (C macro): Multi-phase initialization.
                                                             (line  132)
* Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED (C macro): Multi-phase initialization.
                                                             (line  136)
* Py_MOD_PER_INTERPRETER_GIL_SUPPORTED (C macro): Multi-phase initialization.
                                                             (line  142)
* PY_MONITORING_EVENT_BRANCH (C macro):  Managing the Monitoring State.
                                                             (line   44)
* PY_MONITORING_EVENT_C_RAISE (C macro): Managing the Monitoring State.
                                                             (line   50)
* PY_MONITORING_EVENT_C_RETURN (C macro): Managing the Monitoring State.
                                                             (line   53)
* PY_MONITORING_EVENT_CALL (C macro):    Managing the Monitoring State.
                                                             (line   47)
* PY_MONITORING_EVENT_EXCEPTION_HANDLED (C macro): Managing the Monitoring State.
                                                             (line   56)
* PY_MONITORING_EVENT_INSTRUCTION (C macro): Managing the Monitoring State.
                                                             (line   59)
* PY_MONITORING_EVENT_JUMP (C macro):    Managing the Monitoring State.
                                                             (line   62)
* PY_MONITORING_EVENT_LINE (C macro):    Managing the Monitoring State.
                                                             (line   65)
* PY_MONITORING_EVENT_PY_RESUME (C macro): Managing the Monitoring State.
                                                             (line   68)
* PY_MONITORING_EVENT_PY_RETURN (C macro): Managing the Monitoring State.
                                                             (line   71)
* PY_MONITORING_EVENT_PY_START (C macro): Managing the Monitoring State.
                                                             (line   74)
* PY_MONITORING_EVENT_PY_THROW (C macro): Managing the Monitoring State.
                                                             (line   77)
* PY_MONITORING_EVENT_PY_UNWIND (C macro): Managing the Monitoring State.
                                                             (line   80)
* PY_MONITORING_EVENT_PY_YIELD (C macro): Managing the Monitoring State.
                                                             (line   83)
* PY_MONITORING_EVENT_RAISE (C macro):   Managing the Monitoring State.
                                                             (line   86)
* PY_MONITORING_EVENT_RERAISE (C macro): Managing the Monitoring State.
                                                             (line   89)
* PY_MONITORING_EVENT_STOP_ITERATION (C macro): Managing the Monitoring State.
                                                             (line   92)
* PY_MONITORING_IS_INSTRUMENTED_EVENT (C function): Managing the Monitoring State.
                                                             (line  100)
* Py_mp_ass_subscript (C macro):         Mapping Object Structures.
                                                             (line   37)
* Py_mp_length (C macro):                Mapping Object Structures.
                                                             (line   15)
* Py_mp_subscript (C macro):             Mapping Object Structures.
                                                             (line   25)
* Py_NAN (C macro):                      Floating-Point Objects.
                                                             (line   75)
* Py_nb_absolute (C macro):              Number Object Structures.
                                                             (line  121)
* Py_nb_add (C macro):                   Number Object Structures.
                                                             (line   73)
* Py_nb_and (C macro):                   Number Object Structures.
                                                             (line  149)
* Py_nb_bool (C macro):                  Number Object Structures.
                                                             (line  126)
* Py_nb_divmod (C macro):                Number Object Structures.
                                                             (line   97)
* Py_nb_float (C macro):                 Number Object Structures.
                                                             (line  172)
* Py_nb_floor_divide (C macro):          Number Object Structures.
                                                             (line  238)
* Py_nb_index (C macro):                 Number Object Structures.
                                                             (line  262)
* Py_nb_inplace_add (C macro):           Number Object Structures.
                                                             (line  178)
* Py_nb_inplace_and (C macro):           Number Object Structures.
                                                             (line  220)
* Py_nb_inplace_floor_divide (C macro):  Number Object Structures.
                                                             (line  251)
* Py_nb_inplace_lshift (C macro):        Number Object Structures.
                                                             (line  208)
* Py_nb_inplace_matrix_multiply (C macro): Number Object Structures.
                                                             (line  275)
* Py_nb_inplace_multiply (C macro):      Number Object Structures.
                                                             (line  190)
* Py_nb_inplace_or (C macro):            Number Object Structures.
                                                             (line  232)
* Py_nb_inplace_power (C macro):         Number Object Structures.
                                                             (line  202)
* Py_nb_inplace_remainder (C macro):     Number Object Structures.
                                                             (line  196)
* Py_nb_inplace_rshift (C macro):        Number Object Structures.
                                                             (line  214)
* Py_nb_inplace_subtract (C macro):      Number Object Structures.
                                                             (line  184)
* Py_nb_inplace_true_divide (C macro):   Number Object Structures.
                                                             (line  257)
* Py_nb_inplace_xor (C macro):           Number Object Structures.
                                                             (line  226)
* Py_nb_int (C macro):                   Number Object Structures.
                                                             (line  164)
* Py_nb_invert (C macro):                Number Object Structures.
                                                             (line  132)
* Py_nb_lshift (C macro):                Number Object Structures.
                                                             (line  138)
* Py_nb_matrix_multiply (C macro):       Number Object Structures.
                                                             (line  268)
* Py_nb_multiply (C macro):              Number Object Structures.
                                                             (line   85)
* Py_nb_negative (C macro):              Number Object Structures.
                                                             (line  109)
* Py_nb_or (C macro):                    Number Object Structures.
                                                             (line  159)
* Py_nb_positive (C macro):              Number Object Structures.
                                                             (line  115)
* Py_nb_power (C macro):                 Number Object Structures.
                                                             (line  103)
* Py_nb_remainder (C macro):             Number Object Structures.
                                                             (line   91)
* Py_nb_rshift (C macro):                Number Object Structures.
                                                             (line  144)
* Py_nb_subtract (C macro):              Number Object Structures.
                                                             (line   79)
* Py_nb_true_divide (C macro):           Number Object Structures.
                                                             (line  244)
* Py_nb_xor (C macro):                   Number Object Structures.
                                                             (line  154)
* Py_NE (C macro):                       PyTypeObject Slots. (line 1158)
* Py_NewInterpreter (C function):        Sub-interpreter support.
                                                             (line  196)
* Py_NewInterpreterFromConfig (C function): Sub-interpreter support.
                                                             (line  109)
* Py_NewRef (C function):                Reference Counting. (line   72)
* Py_NO_INLINE (C macro):                Useful macros.      (line  191)
* Py_None (C var):                       The None Object.    (line   11)
* Py_NoSiteFlag (C var):                 Global configuration variables.
                                                             (line  178)
* Py_NotImplemented (C var):             Object Protocol.    (line   71)
* Py_NoUserSiteDirectory (C var):        Global configuration variables.
                                                             (line  194)
* py_object (class in ctypes):           Fundamental data types<2>.
                                                             (line  220)
* Py_OpenCodeHookFunction (C type):      File Objects.       (line   65)
* Py_OptimizeFlag (C var):               Global configuration variables.
                                                             (line  208)
* Py_PreInitialize (C function):         Preinitialize Python with PyPreConfig.
                                                             (line   21)
* Py_PreInitializeFromArgs (C function): Preinitialize Python with PyPreConfig.
                                                             (line   38)
* Py_PreInitializeFromBytesArgs (C function): Preinitialize Python with PyPreConfig.
                                                             (line   28)
* Py_PRINT_RAW (C macro):                Object Protocol.    (line   82)
* Py_PRINT_RAW (C macro) <1>:            File Objects.       (line  117)
* Py_QuietFlag (C var):                  Global configuration variables.
                                                             (line  219)
* Py_READONLY (C macro):                 Member flags.       (line    8)
* Py_REFCNT (C function):                Reference Counting. (line    9)
* Py_RELATIVE_OFFSET (C macro):          Member flags.       (line   16)
* PY_RELEASE_LEVEL (C macro):            API and ABI Versioning.
                                                             (line   25)
* PY_RELEASE_SERIAL (C macro):           API and ABI Versioning.
                                                             (line   30)
* Py_ReprEnter (C function):             Recursion Control.  (line   47)
* Py_ReprLeave (C function):             Recursion Control.  (line   64)
* PY_RESUME (monitoring event):          Events.             (line   43)
* PY_RETURN (monitoring event):          Events.             (line   48)
* Py_RETURN_FALSE (C macro):             Boolean Objects.    (line   37)
* Py_RETURN_INF (C macro):               Floating-Point Objects.
                                                             (line  123)
* Py_RETURN_NAN (C macro):               Floating-Point Objects.
                                                             (line  116)
* Py_RETURN_NONE (C macro):              The None Object.    (line   19)
* Py_RETURN_NOTIMPLEMENTED (C macro):    Object Protocol.    (line   76)
* Py_RETURN_RICHCOMPARE (C macro):       PyTypeObject Slots. (line 1170)
* Py_RETURN_TRUE (C macro):              Boolean Objects.    (line   41)
* Py_RunMain (C function):               Initializing and finalizing the interpreter.
                                                             (line  175)
* Py_SAFE_DOWNCAST (C macro):            Useful macros.      (line  203)
* Py_SET_REFCNT (C function):            Reference Counting. (line   29)
* Py_SET_SIZE (C function):              Base object types and macros.
                                                             (line  121)
* Py_SET_TYPE (C function):              Base object types and macros.
                                                             (line  105)
* Py_SetProgramName (C function):        Process-wide parameters.
                                                             (line    6)
* Py_SetPythonHome (C function):         Process-wide parameters.
                                                             (line  289)
* Py_SetRecursionLimit (C function):     Recursion Control.  (line   83)
* Py_SETREF (C macro):                   Reference Counting. (line  173)
* Py_single_input (C var):               Available start symbols.
                                                             (line   18)
* Py_SIZE (C function):                  Base object types and macros.
                                                             (line  111)
* Py_sq_ass_item (C macro):              Sequence Object Structures.
                                                             (line   66)
* Py_sq_concat (C macro):                Sequence Object Structures.
                                                             (line   26)
* Py_sq_contains (C macro):              Sequence Object Structures.
                                                             (line   79)
* Py_sq_inplace_concat (C macro):        Sequence Object Structures.
                                                             (line   90)
* Py_sq_inplace_repeat (C macro):        Sequence Object Structures.
                                                             (line  104)
* Py_sq_item (C macro):                  Sequence Object Structures.
                                                             (line   47)
* Py_sq_length (C macro):                Sequence Object Structures.
                                                             (line   15)
* Py_sq_repeat (C macro):                Sequence Object Structures.
                                                             (line   36)
* Py_ssize_t (C type):                   Types.              (line   14)
* PY_SSIZE_T_MAX (C macro):              Integer Objects.    (line  249)
* PY_START (monitoring event):           Events.             (line   53)
* Py_STRINGIFY (C macro):                Useful macros.      (line  220)
* Py_T_BOOL (C macro):                   Member types.       (line   85)
* Py_T_BYTE (C macro):                   Member types.       (line   20)
* Py_T_CHAR (C macro):                   Member types.       (line  100)
* Py_T_DOUBLE (C macro):                 Member types.       (line   80)
* Py_T_FLOAT (C macro):                  Member types.       (line   75)
* Py_T_INT (C macro):                    Member types.       (line   30)
* Py_T_LONG (C macro):                   Member types.       (line   35)
* Py_T_LONGLONG (C macro):               Member types.       (line   40)
* Py_T_OBJECT_EX (C macro):              Member types.       (line  105)
* Py_T_PYSSIZET (C macro):               Member types.       (line   70)
* Py_T_SHORT (C macro):                  Member types.       (line   25)
* Py_T_STRING (C macro):                 Member types.       (line   90)
* Py_T_STRING_INPLACE (C macro):         Member types.       (line   95)
* Py_T_UBYTE (C macro):                  Member types.       (line   45)
* Py_T_UINT (C macro):                   Member types.       (line   50)
* Py_T_ULONG (C macro):                  Member types.       (line   60)
* Py_T_ULONGLONG (C macro):              Member types.       (line   65)
* Py_T_USHORT (C macro):                 Member types.       (line   55)
* PY_THROW (monitoring event):           Events.             (line   58)
* Py_TOLOWER (C macro):                  Character classification and conversion.
                                                             (line   43)
* Py_TOUPPER (C macro):                  Character classification and conversion.
                                                             (line   47)
* Py_tp_alloc (C macro):                 PyTypeObject Slots. (line 1530)
* Py_tp_base (C macro):                  PyTypeObject Slots. (line 1342)
* Py_tp_bases (C macro):                 PyTypeObject Slots. (line 1657)
* Py_tp_call (C macro):                  PyTypeObject Slots. (line  415)
* Py_tp_clear (C macro):                 PyTypeObject Slots. (line 1042)
* Py_tp_dealloc (C macro):               PyTypeObject Slots. (line  136)
* Py_tp_del (C macro):                   PyTypeObject Slots. (line 1733)
* Py_tp_descr_get (C macro):             PyTypeObject Slots. (line 1414)
* Py_tp_descr_set (C macro):             PyTypeObject Slots. (line 1430)
* Py_tp_doc (C macro):                   PyTypeObject Slots. (line  929)
* Py_tp_finalize (C macro):              PyTypeObject Slots. (line 1749)
* Py_tp_free (C macro):                  PyTypeObject Slots. (line 1598)
* Py_tp_getattr (C macro):               PyTypeObject Slots. (line  246)
* Py_tp_getattro (C macro):              PyTypeObject Slots. (line  460)
* Py_tp_getset (C macro):                PyTypeObject Slots. (line 1324)
* Py_tp_hash (C macro):                  PyTypeObject Slots. (line  371)
* Py_tp_init (C macro):                  PyTypeObject Slots. (line 1492)
* Py_tp_is_gc (C macro):                 PyTypeObject Slots. (line 1625)
* Py_tp_iter (C macro):                  PyTypeObject Slots. (line 1240)
* Py_tp_iternext (C macro):              PyTypeObject Slots. (line 1260)
* Py_tp_members (C macro):               PyTypeObject Slots. (line 1305)
* Py_tp_methods (C macro):               PyTypeObject Slots. (line 1286)
* Py_tp_new (C macro):                   PyTypeObject Slots. (line 1556)
* Py_tp_repr (C macro):                  PyTypeObject Slots. (line  306)
* Py_tp_richcompare (C macro):           PyTypeObject Slots. (line 1126)
* Py_tp_setattr (C macro):               PyTypeObject Slots. (line  268)
* Py_tp_setattro (C macro):              PyTypeObject Slots. (line  490)
* Py_tp_str (C macro):                   PyTypeObject Slots. (line  430)
* Py_tp_traverse (C macro):              PyTypeObject Slots. (line  943)
* Py_TPFLAGS_BASE_EXC_SUBCLASS (C macro): PyTypeObject Slots.
                                                             (line  737)
* Py_TPFLAGS_BASETYPE (C macro):         PyTypeObject Slots. (line  588)
* Py_TPFLAGS_BYTES_SUBCLASS (C macro):   PyTypeObject Slots. (line  731)
* Py_TPFLAGS_DEFAULT (C macro):          PyTypeObject Slots. (line  637)
* Py_TPFLAGS_DICT_SUBCLASS (C macro):    PyTypeObject Slots. (line  735)
* Py_TPFLAGS_DISALLOW_INSTANTIATION (C macro): PyTypeObject Slots.
                                                             (line  798)
* Py_TPFLAGS_HAVE_FINALIZE (C macro):    PyTypeObject Slots. (line  750)
* Py_TPFLAGS_HAVE_GC (C macro):          PyTypeObject Slots. (line  616)
* Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (C macro): PyTypeObject Slots.
                                                             (line  917)
* Py_TPFLAGS_HAVE_VECTORCALL (C macro):  PyTypeObject Slots. (line  761)
* Py_TPFLAGS_HAVE_VERSION_TAG (C macro): PyTypeObject Slots. (line  883)
* Py_TPFLAGS_HEAPTYPE (C macro):         PyTypeObject Slots. (line  570)
* Py_TPFLAGS_IMMUTABLETYPE (C macro):    PyTypeObject Slots. (line  784)
* Py_TPFLAGS_INLINE_VALUES (C macro):    PyTypeObject Slots. (line  889)
* Py_TPFLAGS_IS_ABSTRACT (C macro):      PyTypeObject Slots. (line  903)
* Py_TPFLAGS_ITEMS_AT_END (C macro):     PyTypeObject Slots. (line  705)
* Py_TPFLAGS_LIST_SUBCLASS (C macro):    PyTypeObject Slots. (line  727)
* Py_TPFLAGS_LONG_SUBCLASS (C macro):    PyTypeObject Slots. (line  725)
* Py_TPFLAGS_MANAGED_DICT (C macro):     PyTypeObject Slots. (line  673)
* Py_TPFLAGS_MANAGED_WEAKREF (C macro):  PyTypeObject Slots. (line  693)
* Py_TPFLAGS_MAPPING (C macro):          PyTypeObject Slots. (line  826)
* Py_TPFLAGS_METHOD_DESCRIPTOR (C macro): PyTypeObject Slots.
                                                             (line  648)
* Py_TPFLAGS_READY (C macro):            PyTypeObject Slots. (line  598)
* Py_TPFLAGS_READYING (C macro):         PyTypeObject Slots. (line  607)
* Py_TPFLAGS_SEQUENCE (C macro):         PyTypeObject Slots. (line  850)
* Py_TPFLAGS_TUPLE_SUBCLASS (C macro):   PyTypeObject Slots. (line  729)
* Py_TPFLAGS_TYPE_SUBCLASS (C macro):    PyTypeObject Slots. (line  739)
* Py_TPFLAGS_UNICODE_SUBCLASS (C macro): PyTypeObject Slots. (line  733)
* Py_TPFLAGS_VALID_VERSION_TAG (C macro): PyTypeObject Slots.
                                                             (line  874)
* Py_tracefunc (C type):                 Profiling and Tracing.
                                                             (line   18)
* Py_True (C var):                       Boolean Objects.    (line   29)
* Py_tss_NEEDS_INIT (C macro):           Thread Specific Storage TSS API.
                                                             (line   28)
* Py_tss_t (C type):                     Thread Specific Storage TSS API.
                                                             (line   17)
* Py_TYPE (C function):                  Base object types and macros.
                                                             (line   86)
* Py_UCS1 (C type):                      Unicode Type.       (line    9)
* Py_UCS2 (C type):                      Unicode Type.       (line    9)
* Py_UCS4 (C type):                      Unicode Type.       (line    9)
* Py_uhash_t (C type):                   PyHash API.         (line   15)
* Py_ULL (C macro):                      Useful macros.      (line  227)
* Py_UNBLOCK_THREADS (C macro):          High-level API.     (line  206)
* Py_UnbufferedStdioFlag (C var):        Global configuration variables.
                                                             (line  234)
* Py_UNICODE (C type):                   Unicode Type.       (line   19)
* Py_UNICODE_HIGH_SURROGATE (C function): Unicode Character Properties.
                                                             (line  107)
* Py_UNICODE_IS_HIGH_SURROGATE (C function): Unicode Character Properties.
                                                             (line   99)
* Py_UNICODE_IS_LOW_SURROGATE (C function): Unicode Character Properties.
                                                             (line  103)
* Py_UNICODE_IS_SURROGATE (C function):  Unicode Character Properties.
                                                             (line   95)
* Py_UNICODE_ISALNUM (C function):       Unicode Character Properties.
                                                             (line   52)
* Py_UNICODE_ISALPHA (C function):       Unicode Character Properties.
                                                             (line   47)
* Py_UNICODE_ISDECIMAL (C function):     Unicode Character Properties.
                                                             (line   35)
* Py_UNICODE_ISDIGIT (C function):       Unicode Character Properties.
                                                             (line   39)
* Py_UNICODE_ISLINEBREAK (C function):   Unicode Character Properties.
                                                             (line   30)
* Py_UNICODE_ISLOWER (C function):       Unicode Character Properties.
                                                             (line   15)
* Py_UNICODE_ISNUMERIC (C function):     Unicode Character Properties.
                                                             (line   43)
* Py_UNICODE_ISPRINTABLE (C function):   Unicode Character Properties.
                                                             (line   57)
* Py_UNICODE_ISSPACE (C function):       Unicode Character Properties.
                                                             (line   10)
* Py_UNICODE_ISTITLE (C function):       Unicode Character Properties.
                                                             (line   25)
* Py_UNICODE_ISUPPER (C function):       Unicode Character Properties.
                                                             (line   20)
* Py_UNICODE_JOIN_SURROGATES (C function): Unicode Character Properties.
                                                             (line  119)
* Py_UNICODE_LOW_SURROGATE (C function): Unicode Character Properties.
                                                             (line  113)
* Py_UNICODE_TODECIMAL (C function):     Unicode Character Properties.
                                                             (line   76)
* Py_UNICODE_TODIGIT (C function):       Unicode Character Properties.
                                                             (line   82)
* Py_UNICODE_TOLOWER (C function):       Unicode Character Properties.
                                                             (line   64)
* Py_UNICODE_TONUMERIC (C function):     Unicode Character Properties.
                                                             (line   88)
* Py_UNICODE_TOTITLE (C function):       Unicode Character Properties.
                                                             (line   72)
* Py_UNICODE_TOUPPER (C function):       Unicode Character Properties.
                                                             (line   68)
* Py_UNREACHABLE (C macro):              Useful macros.      (line  237)
* Py_UNUSED (C macro):                   Useful macros.      (line  262)
* PY_UNWIND (monitoring event):          Events.             (line   62)
* Py_VA_COPY (C macro):                  Useful macros.      (line  381)
* Py_VaBuildValue (C function):          Building values.    (line  202)
* PY_VECTORCALL_ARGUMENTS_OFFSET (C macro): The Vectorcall Protocol.
                                                             (line   69)
* Py_VerboseFlag (C var):                Global configuration variables.
                                                             (line  247)
* Py_Version (C var):                    API and ABI Versioning.
                                                             (line   69)
* PY_VERSION_HEX (C macro):              API and ABI Versioning.
                                                             (line   34)
* Py_VISIT (C macro):                    Supporting Cyclic Garbage Collection.
                                                             (line  184)
* Py_XDECREF (C function):               Exceptions<21>.     (line  123)
* Py_XDECREF (C function) <1>:           Reference Counting. (line  138)
* Py_XINCREF (C function):               Reference Counting. (line   65)
* Py_XNewRef (C function):               Reference Counting. (line   96)
* Py_XSETREF (C macro):                  Reference Counting. (line  199)
* PY_YIELD (monitoring event):           Events.             (line   66)
* PyAIter_Check (C function):            Iterator Protocol.  (line   14)
* PyAnySet_Check (C function):           Set Objects.        (line   54)
* PyAnySet_CheckExact (C function):      Set Objects.        (line   67)
* PyAPI_DATA (C macro):                  Useful macros.      (line  374)
* PyAPI_FUNC (C macro):                  Useful macros.      (line  367)
* PyArg_Parse (C function):              API Functions.      (line   55)
* PyArg_ParseTuple (C function):         Extracting Parameters in Extension Functions.
                                                             (line    6)
* PyArg_ParseTuple (C function) <1>:     API Functions.      (line    6)
* PyArg_ParseTupleAndKeywords (C function): Keyword Parameters for Extension Functions.
                                                             (line    6)
* PyArg_ParseTupleAndKeywords (C function) <1>: API Functions.
                                                             (line   19)
* PyArg_UnpackTuple (C function):        API Functions.      (line   75)
* PyArg_ValidateKeywordArguments (C function): API Functions.
                                                             (line   47)
* PyArg_VaParse (C function):            API Functions.      (line   13)
* PyArg_VaParseTupleAndKeywords (C function): API Functions. (line   40)
* PyASCIIObject (C type):                Unicode Type.       (line   30)
* PyAsyncGen_CheckExact (C function):    Asynchronous Generator Objects.
                                                             (line   32)
* PyAsyncGen_New (C function):           Asynchronous Generator Objects.
                                                             (line   19)
* PyAsyncGen_Type (C var):               Asynchronous Generator Objects.
                                                             (line   11)
* PyAsyncMethods (C type):               Async Object Structures.
                                                             (line    8)
* PyAsyncMethods.am_aiter (C member):    Async Object Structures.
                                                             (line   38)
* PyAsyncMethods.am_anext (C member):    Async Object Structures.
                                                             (line   53)
* PyAsyncMethods.am_await (C member):    Async Object Structures.
                                                             (line   23)
* PyAsyncMethods.am_send (C member):     Async Object Structures.
                                                             (line   65)
* PyBaseObject_Type (C var):             Base object types and macros.
                                                             (line   55)
* PyBool_Check (C function):             Boolean Objects.    (line   16)
* PyBool_FromLong (C function):          Boolean Objects.    (line   45)
* PyBool_Type (C var):                   Boolean Objects.    (line   11)
* PyBUF_ANY_CONTIGUOUS (C macro):        contiguity requests.
                                                             (line   24)
* PyBUF_C_CONTIGUOUS (C macro):          contiguity requests.
                                                             (line   14)
* PyBUF_CONTIG (C macro):                compound requests.  (line   48)
* PyBUF_CONTIG_RO (C macro):             compound requests.  (line   53)
* PyBUF_F_CONTIGUOUS (C macro):          contiguity requests.
                                                             (line   19)
* PyBUF_FORMAT (C macro):                readonly format.    (line   21)
* PyBUF_FULL (C macro):                  compound requests.  (line   18)
* PyBUF_FULL_RO (C macro):               compound requests.  (line   23)
* PyBUF_INDIRECT (C macro):              shape strides suboffsets.
                                                             (line   14)
* PyBUF_MAX_NDIM (C macro):              Buffer structure.   (line  162)
* PyBUF_ND (C macro):                    shape strides suboffsets.
                                                             (line   24)
* PyBUF_READ (C macro):                  MemoryView objects. (line   23)
* PyBUF_RECORDS (C macro):               compound requests.  (line   28)
* PyBUF_RECORDS_RO (C macro):            compound requests.  (line   33)
* PyBUF_SIMPLE (C macro):                shape strides suboffsets.
                                                             (line   29)
* PyBUF_STRIDED (C macro):               compound requests.  (line   38)
* PyBUF_STRIDED_RO (C macro):            compound requests.  (line   43)
* PyBUF_STRIDES (C macro):               shape strides suboffsets.
                                                             (line   19)
* PyBUF_WRITABLE (C macro):              readonly format.    (line    6)
* PyBUF_WRITE (C macro):                 MemoryView objects. (line   27)
* PyBUF_WRITEABLE (C macro):             readonly format.    (line   16)
* PyBuffer_FillContiguousStrides (C function): Buffer-related functions.
                                                             (line   87)
* PyBuffer_FillInfo (C function):        Buffer-related functions.
                                                             (line   96)
* PyBuffer_FromContiguous (C function):  Buffer-related functions.
                                                             (line   63)
* PyBuffer_GetPointer (C function):      Buffer-related functions.
                                                             (line   57)
* PyBuffer_IsContiguous (C function):    Buffer-related functions.
                                                             (line   49)
* PyBuffer_Release (C function):         Buffer-related functions.
                                                             (line   31)
* PyBuffer_SizeFromFormat (C function):  Buffer-related functions.
                                                             (line   41)
* PyBuffer_ToContiguous (C function):    Buffer-related functions.
                                                             (line   70)
* PyBufferProcs (C type):                Buffer Protocol.    (line   20)
* PyBufferProcs (C type) <1>:            Buffer Object Structures.
                                                             (line    6)
* PyBufferProcs.bf_getbuffer (C member): Buffer Object Structures.
                                                             (line   12)
* PyBufferProcs.bf_releasebuffer (C member): Buffer Object Structures.
                                                             (line   63)
* PyByteArray_AS_STRING (C function):    Macros.             (line    8)
* PyByteArray_AsString (C function):     Direct API functions.
                                                             (line   35)
* PyByteArray_Check (C function):        Type check macros.  (line    6)
* PyByteArray_CheckExact (C function):   Type check macros.  (line   11)
* PyByteArray_Concat (C function):       Direct API functions.
                                                             (line   22)
* PyByteArray_FromObject (C function):   Direct API functions.
                                                             (line    6)
* PyByteArray_FromStringAndSize (C function): Direct API functions.
                                                             (line   14)
* PyByteArray_GET_SIZE (C function):     Macros.             (line   13)
* PyByteArray_Resize (C function):       Direct API functions.
                                                             (line   40)
* PyByteArray_Size (C function):         Direct API functions.
                                                             (line   30)
* PyByteArray_Type (C var):              Byte Array Objects. (line   11)
* PyByteArrayIter_Type (C var):          Other Iterator Objects.
                                                             (line    6)
* PyByteArrayObject (C type):            Byte Array Objects. (line    6)
* PyBytes_AS_STRING (C function):        Bytes Objects<2>.   (line  138)
* PyBytes_AsString (C function):         Bytes Objects<2>.   (line  127)
* PyBytes_AsStringAndSize (C function):  Bytes Objects<2>.   (line  143)
* PyBytes_Check (C function):            Bytes Objects<2>.   (line   19)
* PyBytes_CheckExact (C function):       Bytes Objects<2>.   (line   24)
* PyBytes_Concat (C function):           Bytes Objects<2>.   (line  165)
* PyBytes_ConcatAndDel (C function):     Bytes Objects<2>.   (line  175)
* PyBytes_DecodeEscape (C function):     Bytes Objects<2>.   (line  214)
* PyBytes_FromFormat (C function):       Bytes Objects<2>.   (line   43)
* PyBytes_FromFormatV (C function):      Bytes Objects<2>.   (line  108)
* PyBytes_FromObject (C function):       Bytes Objects<2>.   (line  114)
* PyBytes_FromString (C function):       Bytes Objects<2>.   (line   30)
* PyBytes_FromStringAndSize (C function): Bytes Objects<2>.  (line   36)
* PyBytes_GET_SIZE (C function):         Bytes Objects<2>.   (line  123)
* PyBytes_Repr (C function):             Bytes Objects<2>.   (line  195)
* PyBytes_Size (C function):             Bytes Objects<2>.   (line  119)
* PyBytes_Type (C var):                  Bytes Objects<2>.   (line   14)
* PyBytesIter_Type (C var):              Other Iterator Objects.
                                                             (line    9)
* PyBytesObject (C type):                Bytes Objects<2>.   (line    9)
* pycache_prefix (in module sys):        sys — System-specific parameters and functions.
                                                             (line  371)
* PyCallable_Check (C function):         Call Support API.   (line    6)
* PyCallIter_Check (C function):         Iterator Objects.   (line   34)
* PyCallIter_New (C function):           Iterator Objects.   (line   39)
* PyCallIter_Type (C var):               Iterator Objects.   (line   29)
* PyCapsule (C type):                    Capsules<2>.        (line   11)
* PyCapsule_CheckExact (C function):     Capsules<2>.        (line   34)
* PyCapsule_Destructor (C type):         Capsules<2>.        (line   25)
* PyCapsule_GetContext (C function):     Capsules<2>.        (line   81)
* PyCapsule_GetDestructor (C function):  Capsules<2>.        (line   70)
* PyCapsule_GetName (C function):        Capsules<2>.        (line   91)
* PyCapsule_GetPointer (C function):     Capsules<2>.        (line   59)
* PyCapsule_Import (C function):         Capsules<2>.        (line  101)
* PyCapsule_IsValid (C function):        Capsules<2>.        (line  123)
* PyCapsule_New (C function):            Capsules<2>.        (line   39)
* PyCapsule_SetContext (C function):     Capsules<2>.        (line  139)
* PyCapsule_SetDestructor (C function):  Capsules<2>.        (line  147)
* PyCapsule_SetName (C function):        Capsules<2>.        (line  155)
* PyCapsule_SetPointer (C function):     Capsules<2>.        (line  165)
* PyCapsule_Type (C var):                Capsules<2>.        (line   20)
* PyCell_Check (C function):             Cell Objects.       (line   24)
* PyCell_Get (C function):               Cell Objects.       (line   33)
* PyCell_GET (C function):               Cell Objects.       (line   38)
* PyCell_New (C function):               Cell Objects.       (line   29)
* PyCell_Set (C function):               Cell Objects.       (line   43)
* PyCell_SET (C function):               Cell Objects.       (line   52)
* PyCell_Type (C var):                   Cell Objects.       (line   20)
* PyCellObject (C type):                 Cell Objects.       (line   16)
* PyCF_ALLOW_TOP_LEVEL_AWAIT (C macro):  The Very High Level Layer.
                                                             (line  345)
* PyCF_ALLOW_TOP_LEVEL_AWAIT (in module ast): Compiler Flags.
                                                             (line    9)
* PyCF_ONLY_AST (C macro):               The Very High Level Layer.
                                                             (line  345)
* PyCF_ONLY_AST (in module ast):         Compiler Flags.     (line   16)
* PyCF_OPTIMIZED_AST (C macro):          The Very High Level Layer.
                                                             (line  345)
* PyCF_OPTIMIZED_AST (in module ast):    Compiler Flags.     (line   21)
* PyCF_TYPE_COMMENTS (C macro):          The Very High Level Layer.
                                                             (line  345)
* PyCF_TYPE_COMMENTS (in module ast):    Compiler Flags.     (line   28)
* PyCFunction (C type):                  Implementing functions and methods.
                                                             (line    6)
* PyCFunction_Check (C function):        Implementing functions and methods.
                                                             (line  272)
* PyCFunction_CheckExact (C function):   Implementing functions and methods.
                                                             (line  277)
* PyCFunction_GET_FLAGS (C function):    Implementing functions and methods.
                                                             (line  303)
* PyCFunction_GET_FUNCTION (C function): Implementing functions and methods.
                                                             (line  319)
* PyCFunction_GET_SELF (C function):     Implementing functions and methods.
                                                             (line  339)
* PyCFunction_GetFlags (C function):     Implementing functions and methods.
                                                             (line  293)
* PyCFunction_GetFunction (C function):  Implementing functions and methods.
                                                             (line  308)
* PyCFunction_GetSelf (C function):      Implementing functions and methods.
                                                             (line  324)
* PyCFunction_New (C function):          Implementing functions and methods.
                                                             (line  287)
* PyCFunction_NewEx (C function):        Implementing functions and methods.
                                                             (line  282)
* PyCFunction_Type (C var):              Implementing functions and methods.
                                                             (line  267)
* PyCFunctionFast (C type):              Implementing functions and methods.
                                                             (line   29)
* PyCFunctionFastWithKeywords (C type):  Implementing functions and methods.
                                                             (line   38)
* PyCFunctionWithKeywords (C type):      Implementing functions and methods.
                                                             (line   20)
* PycInvalidationMode (class in py_compile): py_compile — Compile Python source files.
                                                             (line   92)
* PyClassMethod_New (C function):        Built-in descriptors.
                                                             (line   23)
* PyClassMethod_Type (C var):            Built-in descriptors.
                                                             (line   11)
* PyClassMethodDescr_Type (C var):       Built-in descriptors.
                                                             (line   16)
* PyCMethod (C type):                    Implementing functions and methods.
                                                             (line   49)
* PyCMethod_Check (C function):          Implementing functions and methods.
                                                             (line  230)
* PyCMethod_CheckExact (C function):     Implementing functions and methods.
                                                             (line  235)
* PyCMethod_New (C function):            Implementing functions and methods.
                                                             (line  240)
* PyCMethod_Type (C var):                Implementing functions and methods.
                                                             (line  224)
* PyCode_Addr2Line (C function):         Code Objects<2>.    (line   97)
* PyCode_Addr2Location (C function):     Code Objects<2>.    (line  106)
* PyCode_AddWatcher (C function):        Code Objects<2>.    (line  163)
* PyCode_Check (C function):             Code Objects<2>.    (line   20)
* PyCode_ClearWatcher (C function):      Code Objects<2>.    (line  172)
* PyCode_GetCellvars (C function):       Code Objects<2>.    (line  142)
* PyCode_GetCode (C function):           Code Objects<2>.    (line  118)
* PyCode_GetFreevars (C function):       Code Objects<2>.    (line  153)
* PyCode_GetNumFree (C function):        Code Objects<2>.    (line   25)
* PyCode_GetVarnames (C function):       Code Objects<2>.    (line  132)
* PyCode_New (C function):               Code Objects<2>.    (line   64)
* PyCode_NewEmpty (C function):          Code Objects<2>.    (line   91)
* PyCode_NewWithPosOnlyArgs (C function): Code Objects<2>.   (line   68)
* PyCode_Optimize (C function):          Code Objects<2>.    (line  224)
* PyCode_Type (C var):                   Code Objects<2>.    (line   15)
* PyCode_WatchCallback (C type):         Code Objects<2>.    (line  188)
* PyCodec_BackslashReplaceErrors (C function): Registry API for Unicode encoding error handlers.
                                                             (line   55)
* PyCodec_Decode (C function):           Codec registry and support functions.
                                                             (line   38)
* PyCodec_Decoder (C function):          Codec lookup API.   (line   16)
* PyCodec_Encode (C function):           Codec registry and support functions.
                                                             (line   27)
* PyCodec_Encoder (C function):          Codec lookup API.   (line   11)
* PyCodec_IgnoreErrors (C function):     Registry API for Unicode encoding error handlers.
                                                             (line   39)
* PyCodec_IncrementalDecoder (C function): Codec lookup API. (line   27)
* PyCodec_IncrementalEncoder (C function): Codec lookup API. (line   21)
* PyCodec_KnownEncoding (C function):    Codec registry and support functions.
                                                             (line   22)
* PyCodec_LookupError (C function):      Registry API for Unicode encoding error handlers.
                                                             (line   27)
* PyCodec_NameReplaceErrors (C function): Registry API for Unicode encoding error handlers.
                                                             (line   61)
* PyCodec_Register (C function):         Codec registry and support functions.
                                                             (line    6)
* PyCodec_RegisterError (C function):    Registry API for Unicode encoding error handlers.
                                                             (line    6)
* PyCodec_ReplaceErrors (C function):    Registry API for Unicode encoding error handlers.
                                                             (line   44)
* PyCodec_StreamReader (C function):     Codec lookup API.   (line   33)
* PyCodec_StreamWriter (C function):     Codec lookup API.   (line   39)
* PyCodec_StrictErrors (C function):     Registry API for Unicode encoding error handlers.
                                                             (line   34)
* PyCodec_Unregister (C function):       Codec registry and support functions.
                                                             (line   14)
* PyCodec_XMLCharRefReplaceErrors (C function): Registry API for Unicode encoding error handlers.
                                                             (line   49)
* PyCodeEvent (C type):                  Code Objects<2>.    (line  181)
* PyCodeObject (C type):                 Code Objects<2>.    (line   10)
* PyCompactUnicodeObject (C type):       Unicode Type.       (line   30)
* PyCompile_OpcodeStackEffect (C function): Stack Effects.   (line   19)
* PyCompile_OpcodeStackEffectWithJump (C function): Stack Effects.
                                                             (line   28)
* PyCompileError:                        py_compile — Compile Python source files.
                                                             (line   19)
* PyCompilerFlags (C struct):            The Very High Level Layer.
                                                             (line  317)
* PyCompilerFlags.cf_feature_version (C member): The Very High Level Layer.
                                                             (line  333)
* PyCompilerFlags.cf_flags (C member):   The Very High Level Layer.
                                                             (line  329)
* PyComplex_AsCComplex (C function):     Complex Numbers as Python Objects.
                                                             (line   70)
* PyComplex_Check (C function):          Complex Numbers as Python Objects.
                                                             (line   16)
* PyComplex_CheckExact (C function):     Complex Numbers as Python Objects.
                                                             (line   21)
* PyComplex_FromCComplex (C function):   Complex Numbers as Python Objects.
                                                             (line   26)
* PyComplex_FromDoubles (C function):    Complex Numbers as Python Objects.
                                                             (line   32)
* PyComplex_ImagAsDouble (C function):   Complex Numbers as Python Objects.
                                                             (line   54)
* PyComplex_RealAsDouble (C function):   Complex Numbers as Python Objects.
                                                             (line   38)
* PyComplex_Type (C var):                Complex Numbers as Python Objects.
                                                             (line   11)
* PyComplexObject (C type):              Complex Numbers as Python Objects.
                                                             (line    6)
* PyConfig (C type):                     PyConfig.           (line    6)
* PyConfig_Clear (C function):           PyConfig.           (line   95)
* PyConfig_InitIsolatedConfig (C function): PyConfig.        (line   20)
* PyConfig_InitPythonConfig (C function): PyConfig.          (line   15)
* PyConfig_Read (C function):            PyConfig.           (line   66)
* PyConfig_SetArgv (C function):         PyConfig.           (line   41)
* PyConfig_SetBytesArgv (C function):    PyConfig.           (line   49)
* PyConfig_SetBytesString (C function):  PyConfig.           (line   32)
* PyConfig_SetString (C function):       PyConfig.           (line   25)
* PyConfig_SetWideStringList (C function): PyConfig.         (line   58)
* PyConfig.argv (C member):              PyConfig.           (line  125)
* PyConfig.base_exec_prefix (C member):  PyConfig.           (line  169)
* PyConfig.base_executable (C member):   PyConfig.           (line  179)
* PyConfig.base_prefix (C member):       PyConfig.           (line  193)
* PyConfig.buffered_stdio (C member):    PyConfig.           (line  203)
* PyConfig.bytes_warning (C member):     PyConfig.           (line  216)
* PyConfig.check_hash_pycs_mode (C member): PyConfig.        (line  253)
* PyConfig.code_debug_ranges (C member): PyConfig.           (line  239)
* PyConfig.configure_c_stdio (C member): PyConfig.           (line  273)
* PyConfig.cpu_count (C member):         PyConfig.           (line  485)
* PyConfig.dev_mode (C member):          PyConfig.           (line  288)
* PyConfig.dump_refs (C member):         PyConfig.           (line  297)
* PyConfig.exec_prefix (C member):       PyConfig.           (line  311)
* PyConfig.executable (C member):        PyConfig.           (line  323)
* PyConfig.faulthandler (C member):      PyConfig.           (line  334)
* PyConfig.filesystem_encoding (C member): PyConfig.         (line  346)
* PyConfig.filesystem_errors (C member): PyConfig.           (line  379)
* PyConfig.hash_seed (C member):         PyConfig.           (line  401)
* PyConfig.home (C member):              PyConfig.           (line  416)
* PyConfig.import_time (C member):       PyConfig.           (line  427)
* PyConfig.inspect (C member):           PyConfig.           (line  436)
* PyConfig.install_signal_handlers (C member): PyConfig.     (line  451)
* PyConfig.int_max_str_digits (C member): PyConfig.          (line  465)
* PyConfig.interactive (C member):       PyConfig.           (line  457)
* PyConfig.isolated (C member):          PyConfig.           (line  499)
* PyConfig.legacy_windows_stdio (C member): PyConfig.        (line  524)
* PyConfig.malloc_stats (C member):      PyConfig.           (line  541)
* PyConfig.module_search_paths (C member): PyConfig.         (line  585)
* PyConfig.module_search_paths_set (C member): PyConfig.     (line  587)
* PyConfig.optimization_level (C member): PyConfig.          (line  601)
* PyConfig.orig_argv (C member):         PyConfig.           (line  617)
* PyConfig.parse_argv (C member):        PyConfig.           (line  634)
* PyConfig.parser_debug (C member):      PyConfig.           (line  654)
* PyConfig.pathconfig_warnings (C member): PyConfig.         (line  668)
* PyConfig.perf_profiling (C member):    PyConfig.           (line  861)
* PyConfig.platlibdir (C member):        PyConfig.           (line  554)
* PyConfig.prefix (C member):            PyConfig.           (line  680)
* PyConfig.program_name (C member):      PyConfig.           (line  691)
* PyConfig.pycache_prefix (C member):    PyConfig.           (line  712)
* PyConfig.pythonpath_env (C member):    PyConfig.           (line  574)
* PyConfig.quiet (C member):             PyConfig.           (line  725)
* PyConfig.run_command (C member):       PyConfig.           (line  734)
* PyConfig.run_filename (C member):      PyConfig.           (line  742)
* PyConfig.run_module (C member):        PyConfig.           (line  756)
* PyConfig.run_presite (C member):       PyConfig.           (line  764)
* PyConfig.safe_path (C member):         PyConfig.           (line  147)
* PyConfig.show_ref_count (C member):    PyConfig.           (line  778)
* PyConfig.site_import (C member):       PyConfig.           (line  790)
* PyConfig.skip_source_first_line (C member): PyConfig.      (line  809)
* PyConfig.stdio_encoding (C member):    PyConfig.           (line  821)
* PyConfig.stdio_errors (C member):      PyConfig.           (line  823)
* PyConfig.tracemalloc (C member):       PyConfig.           (line  850)
* PyConfig.use_environment (C member):   PyConfig.           (line  880)
* PyConfig.use_hash_seed (C member):     PyConfig.           (line  403)
* PyConfig.user_site_directory (C member): PyConfig.         (line  891)
* PyConfig.verbose (C member):           PyConfig.           (line  904)
* PyConfig.warn_default_encoding (C member): PyConfig.       (line  229)
* PyConfig.warnoptions (C member):       PyConfig.           (line  921)
* PyConfig.write_bytecode (C member):    PyConfig.           (line  941)
* PyConfig.xoptions (C member):          PyConfig.           (line  954)
* PyContext (C type):                    Context Variables Objects.
                                                             (line   26)
* PyContext_CheckExact (C function):     Context Variables Objects.
                                                             (line   55)
* PyContext_Copy (C function):           Context Variables Objects.
                                                             (line   76)
* PyContext_CopyCurrent (C function):    Context Variables Objects.
                                                             (line   80)
* PyContext_Enter (C function):          Context Variables Objects.
                                                             (line   84)
* PyContext_Exit (C function):           Context Variables Objects.
                                                             (line   89)
* PyContext_New (C function):            Context Variables Objects.
                                                             (line   72)
* PyContext_Type (C var):                Context Variables Objects.
                                                             (line   41)
* PyContextToken (C type):               Context Variables Objects.
                                                             (line   36)
* PyContextToken_CheckExact (C function): Context Variables Objects.
                                                             (line   65)
* PyContextToken_Type (C var):           Context Variables Objects.
                                                             (line   49)
* PyContextVar (C type):                 Context Variables Objects.
                                                             (line   31)
* PyContextVar_CheckExact (C function):  Context Variables Objects.
                                                             (line   60)
* PyContextVar_Get (C function):         Context Variables Objects.
                                                             (line  105)
* PyContextVar_New (C function):         Context Variables Objects.
                                                             (line   97)
* PyContextVar_Reset (C function):       Context Variables Objects.
                                                             (line  129)
* PyContextVar_Set (C function):         Context Variables Objects.
                                                             (line  123)
* PyContextVar_Type (C var):             Context Variables Objects.
                                                             (line   45)
* PyCoro_CheckExact (C function):        Coroutine Objects<2>.
                                                             (line   19)
* PyCoro_New (C function):               Coroutine Objects<2>.
                                                             (line   24)
* PyCoro_Type (C var):                   Coroutine Objects<2>.
                                                             (line   15)
* PyCoroObject (C type):                 Coroutine Objects<2>.
                                                             (line   11)
* PyCurses_API (C var):                  Curses C API.       (line   29)
* PyCurses_API_pointers (C macro):       Curses C API.       (line   52)
* PyCurses_CAPSULE_NAME (C macro):       Internal data.      (line    9)
* PyCursesInitialised (C macro):         Curses C API.       (line   85)
* PyCursesInitialisedColor (C macro):    Curses C API.       (line   99)
* PyCursesSetupTermCalled (C macro):     Curses C API.       (line   71)
* PyCursesWindow_Check (C function):     Curses C API.       (line   62)
* PyCursesWindow_Type (C var):           Curses C API.       (line   57)
* PyDate_Check (C function):             DateTime Objects<2>.
                                                             (line  104)
* PyDate_CheckExact (C function):        DateTime Objects<2>.
                                                             (line  110)
* PyDate_FromDate (C function):          DateTime Objects<2>.
                                                             (line  161)
* PyDate_FromTimestamp (C function):     DateTime Objects<2>.
                                                             (line  334)
* PyDateTime_CAPI (C type):              DateTime Objects<2>.
                                                             (line   28)
* PyDateTime_CAPSULE_NAME (C macro):     Internal data<2>.   (line    9)
* PyDateTime_Check (C function):         DateTime Objects<2>.
                                                             (line  115)
* PyDateTime_CheckExact (C function):    DateTime Objects<2>.
                                                             (line  121)
* PyDateTime_Date (C type):              DateTime Objects<2>.
                                                             (line   43)
* PyDateTime_DATE_GET_FOLD (C function): DateTime Objects<2>.
                                                             (line  257)
* PyDateTime_DATE_GET_HOUR (C function): DateTime Objects<2>.
                                                             (line  240)
* PyDateTime_DATE_GET_MICROSECOND (C function): DateTime Objects<2>.
                                                             (line  252)
* PyDateTime_DATE_GET_MINUTE (C function): DateTime Objects<2>.
                                                             (line  244)
* PyDateTime_DATE_GET_SECOND (C function): DateTime Objects<2>.
                                                             (line  248)
* PyDateTime_DATE_GET_TZINFO (C function): DateTime Objects<2>.
                                                             (line  263)
* PyDateTime_DateTime (C type):          DateTime Objects<2>.
                                                             (line   48)
* PyDateTime_DateTimeType (C var):       DateTime Objects<2>.
                                                             (line   69)
* PyDateTime_DateType (C var):           DateTime Objects<2>.
                                                             (line   63)
* PyDateTime_Delta (C type):             DateTime Objects<2>.
                                                             (line   58)
* PyDateTime_DELTA_GET_DAYS (C function): DateTime Objects<2>.
                                                             (line  307)
* PyDateTime_DELTA_GET_MICROSECONDS (C function): DateTime Objects<2>.
                                                             (line  319)
* PyDateTime_DELTA_GET_SECONDS (C function): DateTime Objects<2>.
                                                             (line  313)
* PyDateTime_DeltaType (C var):          DateTime Objects<2>.
                                                             (line   81)
* PyDateTime_FromDateAndTime (C function): DateTime Objects<2>.
                                                             (line  166)
* PyDateTime_FromDateAndTimeAndFold (C function): DateTime Objects<2>.
                                                             (line  173)
* PyDateTime_FromTimestamp (C function): DateTime Objects<2>.
                                                             (line  328)
* PyDateTime_GET_DAY (C function):       DateTime Objects<2>.
                                                             (line  232)
* PyDateTime_GET_MONTH (C function):     DateTime Objects<2>.
                                                             (line  228)
* PyDateTime_GET_YEAR (C function):      DateTime Objects<2>.
                                                             (line  224)
* PyDateTime_IMPORT (C macro):           DateTime Objects<2>.
                                                             (line   14)
* PyDateTime_Time (C type):              DateTime Objects<2>.
                                                             (line   53)
* PyDateTime_TIME_GET_FOLD (C function): DateTime Objects<2>.
                                                             (line  290)
* PyDateTime_TIME_GET_HOUR (C function): DateTime Objects<2>.
                                                             (line  274)
* PyDateTime_TIME_GET_MICROSECOND (C function): DateTime Objects<2>.
                                                             (line  286)
* PyDateTime_TIME_GET_MINUTE (C function): DateTime Objects<2>.
                                                             (line  278)
* PyDateTime_TIME_GET_SECOND (C function): DateTime Objects<2>.
                                                             (line  282)
* PyDateTime_TIME_GET_TZINFO (C function): DateTime Objects<2>.
                                                             (line  296)
* PyDateTime_TimeType (C var):           DateTime Objects<2>.
                                                             (line   75)
* PyDateTime_TimeZone_UTC (C var):       DateTime Objects<2>.
                                                             (line   95)
* PyDateTime_TZInfoType (C var):         DateTime Objects<2>.
                                                             (line   87)
* PyDateTimeAPI (C var):                 DateTime Objects<2>.
                                                             (line   36)
* PyDelta_Check (C function):            DateTime Objects<2>.
                                                             (line  137)
* PyDelta_CheckExact (C function):       DateTime Objects<2>.
                                                             (line  143)
* PyDelta_FromDSU (C function):          DateTime Objects<2>.
                                                             (line  195)
* PyDescr_IsData (C function):           Descriptor Objects. (line   66)
* PyDescr_NewClassMethod (C function):   Descriptor Objects. (line   61)
* PyDescr_NewGetSet (C function):        Descriptor Objects. (line   13)
* PyDescr_NewMember (C function):        Descriptor Objects. (line   18)
* PyDescr_NewMethod (C function):        Descriptor Objects. (line   37)
* PyDescr_NewWrapper (C function):       Descriptor Objects. (line   49)
* PyDict_AddWatcher (C function):        Dictionary Objects. (line  338)
* PyDict_Check (C function):             Dictionary Objects. (line   16)
* PyDict_CheckExact (C function):        Dictionary Objects. (line   21)
* PyDict_Clear (C function):             Dictionary Objects. (line   48)
* PyDict_ClearWatcher (C function):      Dictionary Objects. (line  347)
* PyDict_Contains (C function):          Dictionary Objects. (line   52)
* PyDict_ContainsString (C function):    Dictionary Objects. (line   58)
* PyDict_Copy (C function):              Dictionary Objects. (line   66)
* PyDict_DelItem (C function):           Dictionary Objects. (line   85)
* PyDict_DelItemString (C function):     Dictionary Objects. (line   92)
* PyDict_GET_SIZE (C function):          Dictionary Objects. (line  242)
* PyDict_GetItem (C function):           Dictionary Objects. (line  114)
* PyDict_GetItemRef (C function):        Dictionary Objects. (line   97)
* PyDict_GetItemString (C function):     Dictionary Objects. (line  138)
* PyDict_GetItemStringRef (C function):  Dictionary Objects. (line  151)
* PyDict_GetItemWithError (C function):  Dictionary Objects. (line  130)
* PyDict_Items (C function):             Dictionary Objects. (line  221)
* PyDict_Keys (C function):              Dictionary Objects. (line  226)
* PyDict_Merge (C function):             Dictionary Objects. (line  305)
* PyDict_MergeFromSeq2 (C function):     Dictionary Objects. (line  323)
* PyDict_New (C function):               Dictionary Objects. (line   26)
* PyDict_Next (C function):              Dictionary Objects. (line  246)
* PyDict_Pop (C function):               Dictionary Objects. (line  193)
* PyDict_PopString (C function):         Dictionary Objects. (line  212)
* PyDict_SetDefault (C function):        Dictionary Objects. (line  160)
* PyDict_SetDefaultRef (C function):     Dictionary Objects. (line  172)
* PyDict_SetItem (C function):           Dictionary Objects. (line   71)
* PyDict_SetItemString (C function):     Dictionary Objects. (line   79)
* PyDict_Size (C function):              Dictionary Objects. (line  236)
* PyDict_Type (C var):                   Dictionary Objects. (line   11)
* PyDict_Unwatch (C function):           Dictionary Objects. (line  364)
* PyDict_Update (C function):            Dictionary Objects. (line  315)
* PyDict_Values (C function):            Dictionary Objects. (line  231)
* PyDict_Watch (C function):             Dictionary Objects. (line  355)
* PyDict_WatchCallback (C type):         Dictionary Objects. (line  383)
* PyDict_WatchEvent (C type):            Dictionary Objects. (line  374)
* PyDictItems_Check (C function):        Dictionary View Objects.
                                                             (line   38)
* PyDictItems_Type (C var):              Dictionary View Objects.
                                                             (line   33)
* PyDictIterItem_Type (C var):           Other Iterator Objects.
                                                             (line   42)
* PyDictIterKey_Type (C var):            Other Iterator Objects.
                                                             (line   30)
* PyDictIterValue_Type (C var):          Other Iterator Objects.
                                                             (line   36)
* PyDictKeys_Check (C function):         Dictionary View Objects.
                                                             (line   18)
* PyDictKeys_Type (C var):               Dictionary View Objects.
                                                             (line   13)
* PyDictObject (C type):                 Dictionary Objects. (line    6)
* PyDictProxy_New (C function):          Dictionary Objects. (line   30)
* PyDictProxy_Type (C var):              Dictionary Objects. (line   38)
* PyDictRevIterItem_Type (C var):        Other Iterator Objects.
                                                             (line   45)
* PyDictRevIterKey_Type (C var):         Other Iterator Objects.
                                                             (line   33)
* PyDictRevIterValue_Type (C var):       Other Iterator Objects.
                                                             (line   39)
* PyDictValues_Check (C function):       Dictionary View Objects.
                                                             (line   28)
* PyDictValues_Type (C var):             Dictionary View Objects.
                                                             (line   23)
* PyDictViewSet_Check (C function):      Dictionary View Objects.
                                                             (line    6)
* PyDLL (class in ctypes):               Loading shared libraries.
                                                             (line   69)
* PyDoc_STR (C macro):                   Useful macros.      (line  313)
* PyDoc_STRVAR (C macro):                Useful macros.      (line  295)
* PyDoc_VAR (C macro):                   Useful macros.      (line  329)
* PyDTrace_AUDIT (C function):           C Entry Points.     (line   50)
* PyDTrace_AUDIT_ENABLED (C function):   C Probing Checks.   (line   28)
* PyDTrace_FUNCTION_ENTRY (C function):  C Entry Points.     (line   20)
* PyDTrace_FUNCTION_ENTRY_ENABLED (C function): C Probing Checks.
                                                             (line    8)
* PyDTrace_FUNCTION_RETURN (C function): C Entry Points.     (line   23)
* PyDTrace_FUNCTION_RETURN_ENABLED (C function): C Probing Checks.
                                                             (line   10)
* PyDTrace_GC_DONE (C function):         C Entry Points.     (line   29)
* PyDTrace_GC_DONE_ENABLED (C function): C Probing Checks.   (line   14)
* PyDTrace_GC_START (C function):        C Entry Points.     (line   26)
* PyDTrace_GC_START_ENABLED (C function): C Probing Checks.  (line   12)
* PyDTrace_IMPORT_FIND_LOAD_DONE (C function): C Entry Points.
                                                             (line   47)
* PyDTrace_IMPORT_FIND_LOAD_DONE_ENABLED (C function): C Probing Checks.
                                                             (line   26)
* PyDTrace_IMPORT_FIND_LOAD_START (C function): C Entry Points.
                                                             (line   44)
* PyDTrace_IMPORT_FIND_LOAD_START_ENABLED (C function): C Probing Checks.
                                                             (line   24)
* PyDTrace_INSTANCE_DELETE_DONE (C function): C Entry Points.
                                                             (line   41)
* PyDTrace_INSTANCE_DELETE_DONE_ENABLED (C function): C Probing Checks.
                                                             (line   22)
* PyDTrace_INSTANCE_DELETE_START (C function): C Entry Points.
                                                             (line   38)
* PyDTrace_INSTANCE_DELETE_START_ENABLED (C function): C Probing Checks.
                                                             (line   20)
* PyDTrace_INSTANCE_NEW_DONE (C function): C Entry Points.   (line   35)
* PyDTrace_INSTANCE_NEW_DONE_ENABLED (C function): C Probing Checks.
                                                             (line   18)
* PyDTrace_INSTANCE_NEW_START (C function): C Entry Points.  (line   32)
* PyDTrace_INSTANCE_NEW_START_ENABLED (C function): C Probing Checks.
                                                             (line   16)
* PyDTrace_LINE (C function):            C Entry Points.     (line   17)
* PyDTrace_LINE_ENABLED (C function):    C Probing Checks.   (line    6)
* PyEllipsis_Type (C var):               Ellipsis Object.    (line    6)
* PyEnum_Type (C var):                   Builtin Iterator Types.
                                                             (line   13)
* PyErr_BadArgument (C function):        Raising exceptions. (line   46)
* PyErr_BadInternalCall (C function):    Raising exceptions. (line  228)
* PyErr_CheckSignals (C function):       Signal Handling<2>. (line    6)
* PyErr_Clear (C function):              Exceptions<21>.     (line   25)
* PyErr_Clear (C function) <1>:          Exceptions<21>.     (line  123)
* PyErr_Clear (C function) <2>:          Printing and clearing.
                                                             (line    6)
* PyErr_DisplayException (C function):   Printing and clearing.
                                                             (line   67)
* PyErr_ExceptionMatches (C function):   Exceptions<21>.     (line  123)
* PyErr_ExceptionMatches (C function) <1>: Querying the error indicator.
                                                             (line   22)
* PyErr_Fetch (C function):              Finalization and De-allocation.
                                                             (line   33)
* PyErr_Fetch (C function) <1>:          Querying the error indicator.
                                                             (line   74)
* PyErr_Format (C function):             Raising exceptions. (line   25)
* PyErr_FormatUnraisable (C function):   Printing and clearing.
                                                             (line   56)
* PyErr_FormatV (C function):            Raising exceptions. (line   34)
* PyErr_GetExcInfo (C function):         Querying the error indicator.
                                                             (line  178)
* PyErr_GetHandledException (C function): Querying the error indicator.
                                                             (line  149)
* PyErr_GetRaisedException (C function): Querying the error indicator.
                                                             (line   36)
* PyErr_GivenExceptionMatches (C function): Querying the error indicator.
                                                             (line   28)
* PyErr_NewException (C function):       Exception Classes.  (line    6)
* PyErr_NewExceptionWithDoc (C function): Exception Classes. (line   24)
* PyErr_NoMemory (C function):           Raising exceptions. (line   52)
* PyErr_NormalizeException (C function): Querying the error indicator.
                                                             (line  125)
* PyErr_Occurred (C function):           Exceptions<21>.     (line   12)
* PyErr_Occurred (C function) <1>:       Querying the error indicator.
                                                             (line    6)
* PyErr_Print (C function):              Printing and clearing.
                                                             (line   30)
* PyErr_PrintEx (C function):            Printing and clearing.
                                                             (line   10)
* PyErr_ProgramText (C function):        Raising exceptions. (line  245)
* PyErr_ProgramTextObject (C function):  Raising exceptions. (line  235)
* PyErr_RangedSyntaxLocationObject (C function): Raising exceptions.
                                                             (line  203)
* PyErr_ResourceWarning (C function):    Issuing warnings.   (line   80)
* PyErr_Restore (C function):            Finalization and De-allocation.
                                                             (line   33)
* PyErr_Restore (C function) <1>:        Querying the error indicator.
                                                             (line  102)
* PyErr_SetExcFromWindowsErr (C function): Raising exceptions.
                                                             (line  117)
* PyErr_SetExcFromWindowsErrWithFilename (C function): Raising exceptions.
                                                             (line  163)
* PyErr_SetExcFromWindowsErrWithFilenameObject (C function): Raising exceptions.
                                                             (line  139)
* PyErr_SetExcFromWindowsErrWithFilenameObjects (C function): Raising exceptions.
                                                             (line  151)
* PyErr_SetExcInfo (C function):         Querying the error indicator.
                                                             (line  197)
* PyErr_SetFromErrno (C function):       Raising exceptions. (line   58)
* PyErr_SetFromErrnoWithFilename (C function): Raising exceptions.
                                                             (line   95)
* PyErr_SetFromErrnoWithFilenameObject (C function): Raising exceptions.
                                                             (line   74)
* PyErr_SetFromErrnoWithFilenameObjects (C function): Raising exceptions.
                                                             (line   84)
* PyErr_SetFromWindowsErr (C function):  Raising exceptions. (line  102)
* PyErr_SetFromWindowsErrWithFilename (C function): Raising exceptions.
                                                             (line  126)
* PyErr_SetHandledException (C function): Querying the error indicator.
                                                             (line  165)
* PyErr_SetImportError (C function):     Raising exceptions. (line  173)
* PyErr_SetImportErrorSubclass (C function): Raising exceptions.
                                                             (line  183)
* PyErr_SetInterrupt (C function):       Signal Handling<2>. (line   45)
* PyErr_SetInterruptEx (C function):     Signal Handling<2>. (line   54)
* PyErr_SetNone (C function):            Raising exceptions. (line   42)
* PyErr_SetObject (C function):          Raising exceptions. (line   20)
* PyErr_SetRaisedException (C function): Querying the error indicator.
                                                             (line   64)
* PyErr_SetString (C function):          Exceptions<21>.     (line   25)
* PyErr_SetString (C function) <1>:      Raising exceptions. (line   10)
* PyErr_SyntaxLocation (C function):     Raising exceptions. (line  222)
* PyErr_SyntaxLocationEx (C function):   Raising exceptions. (line  213)
* PyErr_SyntaxLocationObject (C function): Raising exceptions.
                                                             (line  193)
* PyErr_WarnEx (C function):             Issuing warnings.   (line   19)
* PyErr_WarnExplicit (C function):       Issuing warnings.   (line   54)
* PyErr_WarnExplicitFormat (C function): Issuing warnings.   (line   70)
* PyErr_WarnExplicitObject (C function): Issuing warnings.   (line   42)
* PyErr_WarnFormat (C function):         Issuing warnings.   (line   62)
* PyErr_WriteUnraisable (C function):    Printing and clearing.
                                                             (line   34)
* PyEval_AcquireThread (C function):     Low-level API.      (line  227)
* PyEval_AcquireThread():                High-level API.     (line   35)
* PyEval_EvalCode (C function):          The Very High Level Layer.
                                                             (line  271)
* PyEval_EvalCodeEx (C function):        The Very High Level Layer.
                                                             (line  278)
* PyEval_EvalFrame (C function):         The Very High Level Layer.
                                                             (line  291)
* PyEval_EvalFrameEx (C function):       The Very High Level Layer.
                                                             (line  297)
* PyEval_GetBuiltins (C function):       Reflection.         (line    6)
* PyEval_GetFrame (C function):          Reflection.         (line   60)
* PyEval_GetFrameBuiltins (C function):  Reflection.         (line   67)
* PyEval_GetFrameGlobals (C function):   Reflection.         (line   89)
* PyEval_GetFrameLocals (C function):    Reflection.         (line   75)
* PyEval_GetFuncDesc (C function):       Reflection.         (line  103)
* PyEval_GetFuncName (C function):       Reflection.         (line   98)
* PyEval_GetGlobals (C function):        Reflection.         (line   50)
* PyEval_GetLocals (C function):         Reflection.         (line   17)
* PyEval_InitThreads (C function):       High-level API.     (line   34)
* PyEval_InitThreads():                  Initializing and finalizing the interpreter.
                                                             (line    7)
* PyEval_MergeCompilerFlags (C function): The Very High Level Layer.
                                                             (line  312)
* PyEval_ReleaseThread (C function):     Low-level API.      (line  250)
* PyEval_ReleaseThread():                High-level API.     (line   35)
* PyEval_RestoreThread (C function):     Releasing the GIL from extension code.
                                                             (line   33)
* PyEval_RestoreThread (C function) <1>: High-level API.     (line   60)
* PyEval_RestoreThread():                High-level API.     (line   35)
* PyEval_SaveThread (C function):        Releasing the GIL from extension code.
                                                             (line   33)
* PyEval_SaveThread (C function) <1>:    High-level API.     (line   53)
* PyEval_SaveThread():                   High-level API.     (line   35)
* PyEval_SetProfile (C function):        Profiling and Tracing.
                                                             (line  117)
* PyEval_SetProfileAllThreads (C function): Profiling and Tracing.
                                                             (line  132)
* PyEval_SetTrace (C function):          Profiling and Tracing.
                                                             (line  147)
* PyEval_SetTraceAllThreads (C function): Profiling and Tracing.
                                                             (line  162)
* PyExc_ArithmeticError (C var):         Exception types.    (line   23)
* PyExc_AssertionError (C var):          Exception types.    (line   27)
* PyExc_AttributeError (C var):          Exception types.    (line   31)
* PyExc_BaseException (C var):           Exception types.    (line   10)
* PyExc_BaseExceptionGroup (C var):      Exception types.    (line   14)
* PyExc_BlockingIOError (C var):         Exception types.    (line   35)
* PyExc_BrokenPipeError (C var):         Exception types.    (line   40)
* PyExc_BufferError (C var):             Exception types.    (line   45)
* PyExc_BytesWarning (C var):            Warning types.      (line   13)
* PyExc_ChildProcessError (C var):       Exception types.    (line   49)
* PyExc_ConnectionAbortedError (C var):  Exception types.    (line   54)
* PyExc_ConnectionError (C var):         Exception types.    (line   59)
* PyExc_ConnectionRefusedError (C var):  Exception types.    (line   64)
* PyExc_ConnectionResetError (C var):    Exception types.    (line   69)
* PyExc_DeprecationWarning (C var):      Warning types.      (line   17)
* PyExc_EncodingWarning (C var):         Warning types.      (line   21)
* PyExc_EnvironmentError (C var):        OSError aliases.    (line   15)
* PyExc_EOFError (C var):                Exception types.    (line   74)
* PyExc_Exception (C var):               Exception types.    (line   19)
* PyExc_FileExistsError (C var):         Exception types.    (line   77)
* PyExc_FileNotFoundError (C var):       Exception types.    (line   82)
* PyExc_FloatingPointError (C var):      Exception types.    (line   87)
* PyExc_FutureWarning (C var):           Warning types.      (line   26)
* PyExc_GeneratorExit (C var):           Exception types.    (line   91)
* PyExc_ImportError (C var):             Exception types.    (line   95)
* PyExc_ImportWarning (C var):           Warning types.      (line   30)
* PyExc_IndentationError (C var):        Exception types.    (line   99)
* PyExc_IndexError (C var):              Exception types.    (line  103)
* PyExc_InterruptedError (C var):        Exception types.    (line  107)
* PyExc_IOError (C var):                 OSError aliases.    (line   21)
* PyExc_IsADirectoryError (C var):       Exception types.    (line  112)
* PyExc_KeyboardInterrupt (C var):       Exception types.    (line  120)
* PyExc_KeyError (C var):                Exception types.    (line  117)
* PyExc_LookupError (C var):             Exception types.    (line  124)
* PyExc_MemoryError (C var):             Exception types.    (line  128)
* PyExc_ModuleNotFoundError (C var):     Exception types.    (line  132)
* PyExc_NameError (C var):               Exception types.    (line  137)
* PyExc_NotADirectoryError (C var):      Exception types.    (line  141)
* PyExc_NotImplementedError (C var):     Exception types.    (line  146)
* PyExc_OSError (C var):                 Exception types.    (line  150)
* PyExc_OverflowError (C var):           Exception types.    (line  153)
* PyExc_PendingDeprecationWarning (C var): Warning types.    (line   34)
* PyExc_PermissionError (C var):         Exception types.    (line  157)
* PyExc_ProcessLookupError (C var):      Exception types.    (line  162)
* PyExc_PythonFinalizationError (C var): Exception types.    (line  167)
* PyExc_RecursionError (C var):          Exception types.    (line  170)
* PyExc_ReferenceError (C var):          Exception types.    (line  175)
* PyExc_ResourceWarning (C var):         Warning types.      (line   38)
* PyExc_RuntimeError (C var):            Exception types.    (line  179)
* PyExc_RuntimeWarning (C var):          Warning types.      (line   43)
* PyExc_StopAsyncIteration (C var):      Exception types.    (line  183)
* PyExc_StopIteration (C var):           Exception types.    (line  188)
* PyExc_SyntaxError (C var):             Exception types.    (line  192)
* PyExc_SyntaxWarning (C var):           Warning types.      (line   47)
* PyExc_SystemError (C var):             Exception types.    (line  196)
* PyExc_SystemExit (C var):              Exception types.    (line  200)
* PyExc_TabError (C var):                Exception types.    (line  204)
* PyExc_TimeoutError (C var):            Exception types.    (line  207)
* PyExc_TypeError (C var):               Exception types.    (line  212)
* PyExc_UnboundLocalError (C var):       Exception types.    (line  216)
* PyExc_UnicodeDecodeError (C var):      Exception types.    (line  220)
* PyExc_UnicodeEncodeError (C var):      Exception types.    (line  224)
* PyExc_UnicodeError (C var):            Exception types.    (line  228)
* PyExc_UnicodeTranslateError (C var):   Exception types.    (line  232)
* PyExc_UnicodeWarning (C var):          Warning types.      (line   51)
* PyExc_UserWarning (C var):             Warning types.      (line   55)
* PyExc_ValueError (C var):              Exception types.    (line  236)
* PyExc_Warning (C var):                 Warning types.      (line   10)
* PyExc_WindowsError (C var):            OSError aliases.    (line   27)
* PyExc_ZeroDivisionError (C var):       Exception types.    (line  240)
* PyException_GetArgs (C function):      Exception Objects.  (line   62)
* PyException_GetCause (C function):     Exception Objects.  (line   44)
* PyException_GetContext (C function):   Exception Objects.  (line   28)
* PyException_GetTraceback (C function): Exception Objects.  (line   15)
* PyException_SetArgs (C function):      Exception Objects.  (line   66)
* PyException_SetCause (C function):     Exception Objects.  (line   52)
* PyException_SetContext (C function):   Exception Objects.  (line   37)
* PyException_SetTraceback (C function): Exception Objects.  (line   23)
* PyExceptionClass_Check (C function):   Exception Classes.  (line   34)
* PyExceptionClass_Name (C function):    Exception Classes.  (line   39)
* PyExceptionInstance_Check (C function): Exception Objects. (line    6)
* PyExceptionInstance_Class (C macro):   Exception Objects.  (line   11)
* PyFile_FromFd (C function):            File Objects.       (line   15)
* PyFile_GetLine (C function):           File Objects.       (line   41)
* PyFile_OpenCode (C function):          File Objects.       (line  108)
* PyFile_OpenCodeObject (C function):    File Objects.       (line   92)
* PyFile_SetOpenCodeHook (C function):   File Objects.       (line   57)
* PyFile_WriteObject (C function):       File Objects.       (line  115)
* PyFile_WriteString (C function):       File Objects.       (line  128)
* PyFilter_Type (C var):                 Builtin Iterator Types.
                                                             (line   16)
* PyFloat_AS_DOUBLE (C function):        Floating-Point Objects.
                                                             (line   48)
* PyFloat_AsDouble (C function):         Floating-Point Objects.
                                                             (line   36)
* PyFloat_Check (C function):            Floating-Point Objects.
                                                             (line   16)
* PyFloat_CheckExact (C function):       Floating-Point Objects.
                                                             (line   21)
* PyFloat_FromDouble (C function):       Floating-Point Objects.
                                                             (line   31)
* PyFloat_FromString (C function):       Floating-Point Objects.
                                                             (line   26)
* PyFloat_GetInfo (C function):          Floating-Point Objects.
                                                             (line   53)
* PyFloat_GetMax (C function):           Floating-Point Objects.
                                                             (line   59)
* PyFloat_GetMin (C function):           Floating-Point Objects.
                                                             (line   63)
* PyFloat_Pack2 (C function):            Pack functions.     (line   22)
* PyFloat_Pack4 (C function):            Pack functions.     (line   26)
* PyFloat_Pack8 (C function):            Pack functions.     (line   30)
* PyFloat_Type (C var):                  Floating-Point Objects.
                                                             (line   11)
* PyFloat_Unpack2 (C function):          Unpack functions.   (line   20)
* PyFloat_Unpack4 (C function):          Unpack functions.   (line   24)
* PyFloat_Unpack8 (C function):          Unpack functions.   (line   28)
* PyFloatObject (C type):                Floating-Point Objects.
                                                             (line    6)
* PyFrame_Check (C function):            Frame Objects.      (line   37)
* PyFrame_FastToLocals (C function):     Legacy Local Variable APIs.
                                                             (line   21)
* PyFrame_FastToLocalsWithError (C function): Legacy Local Variable APIs.
                                                             (line   32)
* PyFrame_GetBack (C function):          Frame Objects.      (line   44)
* PyFrame_GetBuiltins (C function):      Frame Objects.      (line   53)
* PyFrame_GetCode (C function):          Frame Objects.      (line   62)
* PyFrame_GetGenerator (C function):     Frame Objects.      (line   73)
* PyFrame_GetGlobals (C function):       Frame Objects.      (line   84)
* PyFrame_GetLasti (C function):         Frame Objects.      (line   93)
* PyFrame_GetLineNumber (C function):    Frame Objects.      (line  141)
* PyFrame_GetLocals (C function):        Frame Objects.      (line  124)
* PyFrame_GetVar (C function):           Frame Objects.      (line  101)
* PyFrame_GetVarString (C function):     Frame Objects.      (line  117)
* PyFrame_LocalsToFast (C function):     Legacy Local Variable APIs.
                                                             (line    9)
* PyFrame_New (C function):              Frame Objects.      (line   29)
* PyFrame_Type (C var):                  Frame Objects.      (line   21)
* PyFrameLocalsProxy_Check (C function): Frame Locals Proxies.
                                                             (line   20)
* PyFrameLocalsProxy_Type (C var):       Frame Locals Proxies.
                                                             (line   16)
* PyFrameObject (C type):                Frame Objects.      (line    6)
* PyFrozenSet_Check (C function):        Set Objects.        (line   49)
* PyFrozenSet_CheckExact (C function):   Set Objects.        (line   73)
* PyFrozenSet_New (C function):          Set Objects.        (line   86)
* PyFrozenSet_Type (C var):              Set Objects.        (line   35)
* PyFunction_AddWatcher (C function):    Function Objects<3>.
                                                             (line  149)
* PyFunction_Check (C function):         Function Objects<3>.
                                                             (line   18)
* PyFunction_ClearWatcher (C function):  Function Objects<3>.
                                                             (line  159)
* PyFunction_GET_ANNOTATIONS (C function): Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_CLOSURE (C function):   Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_CODE (C function):      Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_DEFAULTS (C function):  Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_GLOBALS (C function):   Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_KW_DEFAULTS (C function): Function Objects<3>.
                                                             (line  131)
* PyFunction_GET_MODULE (C function):    Function Objects<3>.
                                                             (line  131)
* PyFunction_GetAnnotations (C function): Function Objects<3>.
                                                             (line  118)
* PyFunction_GetClosure (C function):    Function Objects<3>.
                                                             (line  104)
* PyFunction_GetCode (C function):       Function Objects<3>.
                                                             (line   46)
* PyFunction_GetDefaults (C function):   Function Objects<3>.
                                                             (line   64)
* PyFunction_GetGlobals (C function):    Function Objects<3>.
                                                             (line   50)
* PyFunction_GetKwDefaults (C function): Function Objects<3>.
                                                             (line   88)
* PyFunction_GetModule (C function):     Function Objects<3>.
                                                             (line   55)
* PyFunction_New (C function):           Function Objects<3>.
                                                             (line   24)
* PyFunction_NewWithQualName (C function): Function Objects<3>.
                                                             (line   36)
* PyFunction_SetAnnotations (C function): Function Objects<3>.
                                                             (line  123)
* PyFunction_SetClosure (C function):    Function Objects<3>.
                                                             (line  110)
* PyFunction_SetDefaults (C function):   Function Objects<3>.
                                                             (line   70)
* PyFunction_SetKwDefaults (C function): Function Objects<3>.
                                                             (line   94)
* PyFunction_SetVectorcall (C function): Function Objects<3>.
                                                             (line   78)
* PyFunction_Type (C var):               Function Objects<3>.
                                                             (line   12)
* PyFunction_WatchCallback (C type):     Function Objects<3>.
                                                             (line  184)
* PyFunction_WatchEvent (C type):        Function Objects<3>.
                                                             (line  168)
* PyFunctionObject (C type):             Function Objects<3>.
                                                             (line    8)
* PYFUNCTYPE() (in module ctypes):       Function prototypes.
                                                             (line   35)
* PyGC_Collect (C function):             Controlling the Garbage Collector State.
                                                             (line    9)
* PyGC_Disable (C function):             Controlling the Garbage Collector State.
                                                             (line   27)
* PyGC_Enable (C function):              Controlling the Garbage Collector State.
                                                             (line   20)
* PyGC_IsEnabled (C function):           Controlling the Garbage Collector State.
                                                             (line   34)
* PyGen_Check (C function):              Generator Objects.  (line   19)
* PyGen_CheckExact (C function):         Generator Objects.  (line   24)
* PyGen_GetCode (C function):            Generator Objects.  (line   42)
* PyGen_New (C function):                Generator Objects.  (line   29)
* PyGen_NewWithQualName (C function):    Generator Objects.  (line   34)
* PyGen_Type (C var):                    Generator Objects.  (line   15)
* PyGenObject (C type):                  Generator Objects.  (line   11)
* PyGetSetDef (C type):                  Defining Getters and Setters.
                                                             (line    6)
* PyGetSetDef.closure (C member):        Defining Getters and Setters.
                                                             (line   28)
* PyGetSetDef.doc (C member):            Defining Getters and Setters.
                                                             (line   24)
* PyGetSetDef.get (C member):            Defining Getters and Setters.
                                                             (line   15)
* PyGetSetDef.name (C member):           Defining Getters and Setters.
                                                             (line   11)
* PyGetSetDef.set (C member):            Defining Getters and Setters.
                                                             (line   19)
* PyGetSetDescr_Type (C var):            Descriptor Objects. (line   30)
* PyGILState_Check (C function):         High-level API.     (line  171)
* PyGILState_Ensure (C function):        High-level API.     (line  120)
* PyGILState_GetThisThreadState (C function): High-level API.
                                                             (line  162)
* PyGILState_Release (C function):       High-level API.     (line  152)
* PyGILState_STATE (C type):             High-level API.     (line  105)
* PyGILState_STATE.PyGILState_LOCKED (C enumerator): High-level API.
                                                             (line  110)
* PyGILState_STATE.PyGILState_UNLOCKED (C enumerator): High-level API.
                                                             (line  115)
* PyHASH_BITS (C macro):                 PyHash API.         (line   73)
* PyHash_FuncDef (C type):               PyHash API.         (line  101)
* PyHash_FuncDef.hash (C member):        PyHash API.         (line  105)
* PyHash_FuncDef.hash_bits (C member):   PyHash API.         (line  117)
* PyHash_FuncDef.name (C member):        PyHash API.         (line  110)
* PyHash_FuncDef.seed_bits (C member):   PyHash API.         (line  124)
* PyHash_GetFuncDef (C function):        PyHash API.         (line  133)
* PyHASH_IMAG (C macro):                 PyHash API.         (line   93)
* PyHASH_INF (C macro):                  PyHash API.         (line   85)
* PyHASH_MODULUS (C macro):              PyHash API.         (line   64)
* PyHASH_MULTIPLIER (C macro):           PyHash API.         (line   79)
* PyImport_AddModule (C function):       Importing Modules<2>.
                                                             (line  122)
* PyImport_AddModuleObject (C function): Importing Modules<2>.
                                                             (line  113)
* PyImport_AddModuleRef (C function):    Importing Modules<2>.
                                                             (line   90)
* PyImport_AppendInittab (C function):   Importing Modules<2>.
                                                             (line  297)
* PyImport_ExecCodeModule (C function):  Importing Modules<2>.
                                                             (line  128)
* PyImport_ExecCodeModuleEx (C function): Importing Modules<2>.
                                                             (line  168)
* PyImport_ExecCodeModuleObject (C function): Importing Modules<2>.
                                                             (line  177)
* PyImport_ExecCodeModuleWithPathnames (C function): Importing Modules<2>.
                                                             (line  191)
* PyImport_ExtendInittab (C function):   Importing Modules<2>.
                                                             (line  324)
* PyImport_FrozenModules (C var):        Importing Modules<2>.
                                                             (line  289)
* PyImport_GetImporter (C function):     Importing Modules<2>.
                                                             (line  239)
* PyImport_GetMagicNumber (C function):  Importing Modules<2>.
                                                             (line  207)
* PyImport_GetMagicTag (C function):     Importing Modules<2>.
                                                             (line  215)
* PyImport_GetModule (C function):       Importing Modules<2>.
                                                             (line  229)
* PyImport_GetModuleDict (C function):   Importing Modules<2>.
                                                             (line  223)
* PyImport_Import (C function):          Importing Modules<2>.
                                                             (line   72)
* PyImport_ImportFrozenModule (C function): Importing Modules<2>.
                                                             (line  266)
* PyImport_ImportFrozenModuleObject (C function): Importing Modules<2>.
                                                             (line  252)
* PyImport_ImportModule (C function):    Importing Modules<2>.
                                                             (line    6)
* PyImport_ImportModuleEx (C function):  Importing Modules<2>.
                                                             (line   28)
* PyImport_ImportModuleLevel (C function): Importing Modules<2>.
                                                             (line   62)
* PyImport_ImportModuleLevelObject (C function): Importing Modules<2>.
                                                             (line   45)
* PyImport_ImportModuleNoBlock (C function): Importing Modules<2>.
                                                             (line   14)
* PyImport_Inittab (C var):              Importing Modules<2>.
                                                             (line  339)
* PyImport_ReloadModule (C function):    Importing Modules<2>.
                                                             (line   83)
* PyIndex_Check (C function):            Number Protocol.    (line  305)
* PyInit_modulename (C function):        Building C and C++ Extensions.
                                                             (line   16)
* PyInstanceMethod_Check (C function):   Instance Method Objects.
                                                             (line   15)
* PyInstanceMethod_Function (C function): Instance Method Objects.
                                                             (line   27)
* PyInstanceMethod_GET_FUNCTION (C function): Instance Method Objects.
                                                             (line   32)
* PyInstanceMethod_New (C function):     Instance Method Objects.
                                                             (line   21)
* PyInstanceMethod_Type (C var):         Instance Method Objects.
                                                             (line   10)
* PyInterpreterConfig (C type):          Sub-interpreter support.
                                                             (line   24)
* PyInterpreterConfig_DEFAULT_GIL (C macro): Sub-interpreter support.
                                                             (line   93)
* PyInterpreterConfig_OWN_GIL (C macro): Sub-interpreter support.
                                                             (line  102)
* PyInterpreterConfig_SHARED_GIL (C macro): Sub-interpreter support.
                                                             (line   98)
* PyInterpreterConfig.allow_daemon_threads (C member): Sub-interpreter support.
                                                             (line   69)
* PyInterpreterConfig.allow_exec (C member): Sub-interpreter support.
                                                             (line   54)
* PyInterpreterConfig.allow_fork (C member): Sub-interpreter support.
                                                             (line   45)
* PyInterpreterConfig.allow_threads (C member): Sub-interpreter support.
                                                             (line   64)
* PyInterpreterConfig.check_multi_interp_extensions (C member): Sub-interpreter support.
                                                             (line   76)
* PyInterpreterConfig.gil (C member):    Sub-interpreter support.
                                                             (line   88)
* PyInterpreterConfig.use_main_obmalloc (C member): Sub-interpreter support.
                                                             (line   35)
* PyInterpreterState (C type):           High-level API.     (line    9)
* PyInterpreterState_Clear (C function): Low-level API.      (line   21)
* PyInterpreterState_Delete (C function): Low-level API.     (line   30)
* PyInterpreterState_Get (C function):   Low-level API.      (line  118)
* PyInterpreterState_GetDict (C function): Low-level API.    (line  140)
* PyInterpreterState_GetID (C function): Low-level API.      (line  130)
* PyInterpreterState_Head (C function):  Advanced Debugger Support.
                                                             (line    9)
* PyInterpreterState_Main (C function):  Advanced Debugger Support.
                                                             (line   15)
* PyInterpreterState_New (C function):   Low-level API.      (line   12)
* PyInterpreterState_Next (C function):  Advanced Debugger Support.
                                                             (line   20)
* PyInterpreterState_ThreadHead (C function): Advanced Debugger Support.
                                                             (line   26)
* PyIter_Check (C function):             Iterator Protocol.  (line    8)
* PyIter_Next (C function):              Iterator Protocol.  (line   21)
* PyIter_Send (C function):              Iterator Protocol.  (line   62)
* PYLAUNCHER_ALLOW_INSTALL:              Windows<15>.        (line   24)
* PYLAUNCHER_ALLOW_INSTALL <1>:          Windows<29>.        (line   15)
* PyList_Append (C function):            List Objects.       (line  105)
* PyList_AsTuple (C function):           List Objects.       (line  160)
* PyList_Check (C function):             List Objects.       (line   16)
* PyList_CheckExact (C function):        List Objects.       (line   21)
* PyList_Clear (C function):             List Objects.       (line  139)
* PyList_Extend (C function):            List Objects.       (line  128)
* PyList_GET_ITEM (C function):          List Objects.       (line   67)
* PyList_GET_SIZE (C function):          List Objects.       (line   46)
* PyList_GetItem (C function):           Reference Count Details.
                                                             (line  117)
* PyList_GetItem (C function) <1>:       List Objects.       (line   61)
* PyList_GetItemRef (C function):        List Objects.       (line   50)
* PyList_GetSlice (C function):          List Objects.       (line  111)
* PyList_Insert (C function):            List Objects.       (line   98)
* PyList_New (C function):               List Objects.       (line   26)
* PyList_Reverse (C function):           List Objects.       (line  155)
* PyList_SET_ITEM (C function):          List Objects.       (line   83)
* PyList_SetItem (C function):           Reference Count Details.
                                                             (line   26)
* PyList_SetItem (C function) <1>:       List Objects.       (line   72)
* PyList_SetSlice (C function):          List Objects.       (line  119)
* PyList_Size (C function):              List Objects.       (line   40)
* PyList_Sort (C function):              List Objects.       (line  150)
* PyList_Type (C var):                   List Objects.       (line   11)
* PyListIter_Type (C var):               Other Iterator Objects.
                                                             (line   12)
* PyListObject (C type):                 List Objects.       (line    6)
* PyListRevIter_Type (C var):            Other Iterator Objects.
                                                             (line   15)
* PyLockStatus (C type):                 Legacy Locking APIs.
                                                             (line   16)
* PyLong_AS_LONG (C function):           Integer Objects.    (line  170)
* PyLong_AsDouble (C function):          Integer Objects.    (line  335)
* PyLong_AsInt (C function):             Integer Objects.    (line  179)
* PyLong_AsLong (C function):            Integer Objects.    (line  151)
* PyLong_AsLongAndOverflow (C function): Integer Objects.    (line  186)
* PyLong_AsLongLong (C function):        Integer Objects.    (line  206)
* PyLong_AsLongLongAndOverflow (C function): Integer Objects.
                                                             (line  225)
* PyLong_AsNativeBytes (C function):     Integer Objects.    (line  366)
* PyLong_AsPid (C macro):                Integer Objects.    (line  356)
* PyLong_AsSize_t (C function):          Integer Objects.    (line  272)
* PyLong_AsSsize_t (C function):         Integer Objects.    (line  247)
* PyLong_AsUnsignedLong (C function):    Integer Objects.    (line  260)
* PyLong_AsUnsignedLongLong (C function): Integer Objects.   (line  284)
* PyLong_AsUnsignedLongLongMask (C function): Integer Objects.
                                                             (line  317)
* PyLong_AsUnsignedLongMask (C function): Integer Objects.   (line  300)
* PyLong_AsVoidPtr (C function):         Integer Objects.    (line  346)
* PyLong_Check (C function):             Integer Objects.    (line   22)
* PyLong_CheckExact (C function):        Integer Objects.    (line   27)
* PyLong_FromDouble (C function):        Integer Objects.    (line   69)
* PyLong_FromLong (C function):          Integer Objects.    (line   32)
* PyLong_FromLongLong (C function):      Integer Objects.    (line   58)
* PyLong_FromNativeBytes (C function):   Integer Objects.    (line  112)
* PyLong_FromPid (C macro):              Integer Objects.    (line  141)
* PyLong_FromSize_t (C function):        Integer Objects.    (line   53)
* PyLong_FromSsize_t (C function):       Integer Objects.    (line   48)
* PyLong_FromString (C function):        Integer Objects.    (line   74)
* PyLong_FromUnicodeObject (C function): Integer Objects.    (line   99)
* PyLong_FromUnsignedLong (C function):  Integer Objects.    (line   42)
* PyLong_FromUnsignedLongLong (C function): Integer Objects. (line   63)
* PyLong_FromUnsignedNativeBytes (C function): Integer Objects.
                                                             (line  128)
* PyLong_FromVoidPtr (C function):       Integer Objects.    (line  106)
* PyLong_GetInfo (C function):           Integer Objects.    (line  519)
* PyLong_Type (C var):                   Integer Objects.    (line   17)
* PyLongObject (C type):                 Integer Objects.    (line   13)
* PyLongRangeIter_Type (C var):          Other Iterator Objects.
                                                             (line   27)
* PyMap_Type (C var):                    Builtin Iterator Types.
                                                             (line   20)
* PyMapping_Check (C function):          Mapping Protocol.   (line    9)
* PyMapping_DelItem (C function):        Mapping Protocol.   (line   60)
* PyMapping_DelItemString (C function):  Mapping Protocol.   (line   64)
* PyMapping_GetItemString (C function):  Mapping Protocol.   (line   24)
* PyMapping_GetOptionalItem (C function): Mapping Protocol.  (line   31)
* PyMapping_GetOptionalItemString (C function): Mapping Protocol.
                                                             (line   45)
* PyMapping_HasKey (C function):         Mapping Protocol.   (line   89)
* PyMapping_HasKeyString (C function):   Mapping Protocol.   (line  100)
* PyMapping_HasKeyStringWithError (C function): Mapping Protocol.
                                                             (line   80)
* PyMapping_HasKeyWithError (C function): Mapping Protocol.  (line   71)
* PyMapping_Items (C function):          Mapping Protocol.   (line  129)
* PyMapping_Keys (C function):           Mapping Protocol.   (line  113)
* PyMapping_Length (C function):         Mapping Protocol.   (line   17)
* PyMapping_SetItemString (C function):  Mapping Protocol.   (line   54)
* PyMapping_Size (C function):           Mapping Protocol.   (line   17)
* PyMapping_Values (C function):         Mapping Protocol.   (line  121)
* PyMappingMethods (C type):             Mapping Object Structures.
                                                             (line    6)
* PyMappingMethods.mp_ass_subscript (C member): Mapping Object Structures.
                                                             (line   33)
* PyMappingMethods.mp_length (C member): Mapping Object Structures.
                                                             (line   11)
* PyMappingMethods.mp_subscript (C member): Mapping Object Structures.
                                                             (line   21)
* PyMarshal_ReadLastObjectFromFile (C function): Data marshalling support.
                                                             (line   74)
* PyMarshal_ReadLongFromFile (C function): Data marshalling support.
                                                             (line   47)
* PyMarshal_ReadObjectFromFile (C function): Data marshalling support.
                                                             (line   65)
* PyMarshal_ReadObjectFromString (C function): Data marshalling support.
                                                             (line   90)
* PyMarshal_ReadShortFromFile (C function): Data marshalling support.
                                                             (line   56)
* PyMarshal_WriteLongToFile (C function): Data marshalling support.
                                                             (line   20)
* PyMarshal_WriteObjectToFile (C function): Data marshalling support.
                                                             (line   30)
* PyMarshal_WriteObjectToString (C function): Data marshalling support.
                                                             (line   39)
* PyMem_Calloc (C function):             Memory Interface.   (line   28)
* PyMem_Del (C function):                Memory Interface.   (line   84)
* PyMem_DEL (C macro):                   Deprecated aliases<2>.
                                                             (line   28)
* PYMEM_DOMAIN_MEM (C macro):            Customize Memory Allocators.
                                                             (line   52)
* PYMEM_DOMAIN_OBJ (C macro):            Customize Memory Allocators.
                                                             (line   64)
* PYMEM_DOMAIN_RAW (C macro):            Customize Memory Allocators.
                                                             (line   40)
* PyMem_Free (C function):               Memory Interface.   (line   56)
* PyMem_FREE (C macro):                  Deprecated aliases<2>.
                                                             (line   25)
* PyMem_GetAllocator (C function):       Customize Memory Allocators.
                                                             (line   76)
* PyMem_Malloc (C function):             Memory Interface.   (line   19)
* PyMem_MALLOC (C macro):                Deprecated aliases<2>.
                                                             (line   13)
* PyMem_New (C macro):                   Memory Interface.   (line   68)
* PyMem_NEW (C macro):                   Deprecated aliases<2>.
                                                             (line   16)
* PyMem_RawCalloc (C function):          Raw Memory Interface.
                                                             (line   24)
* PyMem_RawFree (C function):            Raw Memory Interface.
                                                             (line   52)
* PyMem_RawMalloc (C function):          Raw Memory Interface.
                                                             (line   15)
* PyMem_RawRealloc (C function):         Raw Memory Interface.
                                                             (line   36)
* PyMem_Realloc (C function):            Memory Interface.   (line   40)
* PyMem_REALLOC (C macro):               Deprecated aliases<2>.
                                                             (line   19)
* PyMem_Resize (C macro):                Memory Interface.   (line   74)
* PyMem_RESIZE (C macro):                Deprecated aliases<2>.
                                                             (line   22)
* PyMem_SetAllocator (C function):       Customize Memory Allocators.
                                                             (line   81)
* PyMem_SetupDebugHooks (C function):    Customize Memory Allocators.
                                                             (line  124)
* PyMemAllocatorDomain (C type):         Customize Memory Allocators.
                                                             (line   36)
* PyMemAllocatorEx (C type):             Customize Memory Allocators.
                                                             (line    8)
* PyMember_GetOne (C function):          Accessing attributes of extension types.
                                                             (line   71)
* PyMember_SetOne (C function):          Accessing attributes of extension types.
                                                             (line   80)
* PyMemberDef (C type):                  Accessing attributes of extension types.
                                                             (line    6)
* PyMemberDef.doc (C member):            Accessing attributes of extension types.
                                                             (line   36)
* PyMemberDef.flags (C member):          Accessing attributes of extension types.
                                                             (line   31)
* PyMemberDef.name (C member):           Accessing attributes of extension types.
                                                             (line   14)
* PyMemberDef.offset (C member):         Accessing attributes of extension types.
                                                             (line   26)
* PyMemberDef.type (C member):           Accessing attributes of extension types.
                                                             (line   21)
* PyMemberDescr_Type (C var):            Descriptor Objects. (line   23)
* PyMemoryView_Check (C function):       MemoryView objects. (line   59)
* PyMemoryView_FromBuffer (C function):  MemoryView objects. (line   40)
* PyMemoryView_FromMemory (C function):  MemoryView objects. (line   31)
* PyMemoryView_FromObject (C function):  MemoryView objects. (line   15)
* PyMemoryView_GET_BASE (C function):    MemoryView objects. (line   73)
* PyMemoryView_GET_BUFFER (C function):  MemoryView objects. (line   65)
* PyMemoryView_GetContiguous (C function): MemoryView objects.
                                                             (line   47)
* PyMemoryView_Type (C var):             MemoryView objects. (line   10)
* PyMethod_Check (C function):           Method Objects<2>.  (line   16)
* PyMethod_Function (C function):        Method Objects<2>.  (line   29)
* PyMethod_GET_FUNCTION (C function):    Method Objects<2>.  (line   33)
* PyMethod_GET_SELF (C function):        Method Objects<2>.  (line   42)
* PyMethod_New (C function):             Method Objects<2>.  (line   22)
* PyMethod_Self (C function):            Method Objects<2>.  (line   38)
* PyMethod_Type (C var):                 Method Objects<2>.  (line   10)
* PyMethodDef (C type):                  Implementing functions and methods.
                                                             (line   63)
* PyMethodDef.ml_doc (C member):         Implementing functions and methods.
                                                             (line   80)
* PyMethodDef.ml_flags (C member):       Implementing functions and methods.
                                                             (line   76)
* PyMethodDef.ml_meth (C member):        Implementing functions and methods.
                                                             (line   72)
* PyMethodDef.ml_name (C member):        Implementing functions and methods.
                                                             (line   68)
* PyMethodDescr_Type (C var):            Descriptor Objects. (line   42)
* PyMODINIT_FUNC (C macro):              Useful macros.      (line   11)
* PyModule_Add (C function):             Support functions.  (line   63)
* PyModule_AddFunctions (C function):    Low-level module creation functions.
                                                             (line   55)
* PyModule_AddIntConstant (C function):  Support functions.  (line  113)
* PyModule_AddIntMacro (C macro):        Support functions.  (line  136)
* PyModule_AddObject (C function):       Support functions.  (line   79)
* PyModule_AddObjectRef (C function):    Support functions.  (line   11)
* PyModule_AddStringConstant (C function): Support functions.
                                                             (line  124)
* PyModule_AddStringMacro (C macro):     Support functions.  (line  144)
* PyModule_AddType (C function):         Support functions.  (line  148)
* PyModule_Check (C function):           Module Objects.     (line   13)
* PyModule_CheckExact (C function):      Module Objects.     (line   18)
* PyModule_Create (C function):          Single-phase initialization.
                                                             (line   10)
* PyModule_Create2 (C function):         Single-phase initialization.
                                                             (line   16)
* PyModule_ExecDef (C function):         Low-level module creation functions.
                                                             (line   37)
* PyModule_FromDefAndSpec (C function):  Low-level module creation functions.
                                                             (line   11)
* PyModule_FromDefAndSpec2 (C function): Low-level module creation functions.
                                                             (line   20)
* PyModule_GetDef (C function):          Module Objects.     (line   90)
* PyModule_GetDict (C function):         Module Objects.     (line   46)
* PyModule_GetFilename (C function):     Module Objects.     (line  113)
* PyModule_GetFilenameObject (C function): Module Objects.   (line  100)
* PyModule_GetName (C function):         Module Objects.     (line   75)
* PyModule_GetNameObject (C function):   Module Objects.     (line   64)
* PyModule_GetState (C function):        Module Objects.     (line   84)
* PyModule_New (C function):             Module Objects.     (line   41)
* PyModule_NewObject (C function):       Module Objects.     (line   23)
* PyModule_SetDocString (C function):    Low-level module creation functions.
                                                             (line   44)
* PyModule_Type (C var):                 Module Objects.     (line    6)
* PyModuleDef (C type):                  Initializing C modules.
                                                             (line   17)
* PyModuleDef_Init (C function):         Multi-phase initialization.
                                                             (line   47)
* PyModuleDef_Slot (C type):             Multi-phase initialization.
                                                             (line   61)
* PyModuleDef_Slot.slot (C member):      Multi-phase initialization.
                                                             (line   63)
* PyModuleDef_Slot.value (C member):     Multi-phase initialization.
                                                             (line   68)
* PyModuleDef_Type (C var):              Initializing C modules.
                                                             (line  129)
* PyModuleDef.m_base (C member):         Initializing C modules.
                                                             (line   23)
* PyModuleDef.m_clear (C member):        Initializing C modules.
                                                             (line   91)
* PyModuleDef.m_doc (C member):          Initializing C modules.
                                                             (line   31)
* PyModuleDef.m_free (C member):         Initializing C modules.
                                                             (line  113)
* PyModuleDef.m_methods (C member):      Initializing C modules.
                                                             (line   58)
* PyModuleDef.m_name (C member):         Initializing C modules.
                                                             (line   27)
* PyModuleDef.m_size (C member):         Initializing C modules.
                                                             (line   36)
* PyModuleDef.m_slots (C member):        Initializing C modules.
                                                             (line   64)
* PyModuleDef.m_slots.m_reload (C member): Initializing C modules.
                                                             (line   73)
* PyModuleDef.m_traverse (C member):     Initializing C modules.
                                                             (line   75)
* PyMonitoring_EnterScope (C function):  Managing the Monitoring State.
                                                             (line    9)
* PyMonitoring_ExitScope (C function):   Managing the Monitoring State.
                                                             (line   95)
* PyMonitoring_FireBranchEvent (C function): Generating Execution Events.
                                                             (line   70)
* PyMonitoring_FireCallEvent (C function): Generating Execution Events.
                                                             (line   53)
* PyMonitoring_FireCRaiseEvent (C function): Generating Execution Events.
                                                             (line   93)
* PyMonitoring_FireCReturnEvent (C function): Generating Execution Events.
                                                             (line   76)
* PyMonitoring_FireExceptionHandledEvent (C function): Generating Execution Events.
                                                             (line  105)
* PyMonitoring_FireJumpEvent (C function): Generating Execution Events.
                                                             (line   64)
* PyMonitoring_FireLineEvent (C function): Generating Execution Events.
                                                             (line   59)
* PyMonitoring_FirePyResumeEvent (C function): Generating Execution Events.
                                                             (line   38)
* PyMonitoring_FirePyReturnEvent (C function): Generating Execution Events.
                                                             (line   43)
* PyMonitoring_FirePyStartEvent (C function): Generating Execution Events.
                                                             (line   33)
* PyMonitoring_FirePyThrowEvent (C function): Generating Execution Events.
                                                             (line   81)
* PyMonitoring_FirePyUnwindEvent (C function): Generating Execution Events.
                                                             (line  111)
* PyMonitoring_FirePyYieldEvent (C function): Generating Execution Events.
                                                             (line   48)
* PyMonitoring_FireRaiseEvent (C function): Generating Execution Events.
                                                             (line   87)
* PyMonitoring_FireReraiseEvent (C function): Generating Execution Events.
                                                             (line   99)
* PyMonitoring_FireStopIterationEvent (C function): Generating Execution Events.
                                                             (line  117)
* PyMonitoringState (C type):            Generating Execution Events.
                                                             (line   22)
* PyMutex (C type):                      Synchronization Primitives<2>.
                                                             (line    8)
* PyMutex_Lock (C function):             Synchronization Primitives<2>.
                                                             (line   25)
* PyMutex_Unlock (C function):           Synchronization Primitives<2>.
                                                             (line   34)
* PyNumber_Absolute (C function):        Number Protocol.    (line   98)
* PyNumber_Add (C function):             Number Protocol.    (line   13)
* PyNumber_And (C function):             Number Protocol.    (line  124)
* PyNumber_AsSsize_t (C function):       Number Protocol.    (line  290)
* PyNumber_Check (C function):           Number Protocol.    (line    6)
* PyNumber_Divmod (C function):          Number Protocol.    (line   68)
* PyNumber_Float (C function):           Number Protocol.    (line  263)
* PyNumber_FloorDivide (C function):     Number Protocol.    (line   43)
* PyNumber_Index (C function):           Number Protocol.    (line  271)
* PyNumber_InPlaceAdd (C function):      Number Protocol.    (line  145)
* PyNumber_InPlaceAnd (C function):      Number Protocol.    (line  231)
* PyNumber_InPlaceFloorDivide (C function): Number Protocol. (line  176)
* PyNumber_InPlaceLshift (C function):   Number Protocol.    (line  215)
* PyNumber_InPlaceMatrixMultiply (C function): Number Protocol.
                                                             (line  166)
* PyNumber_InPlaceMultiply (C function): Number Protocol.    (line  159)
* PyNumber_InPlaceOr (C function):       Number Protocol.    (line  247)
* PyNumber_InPlacePower (C function):    Number Protocol.    (line  203)
* PyNumber_InPlaceRemainder (C function): Number Protocol.   (line  196)
* PyNumber_InPlaceRshift (C function):   Number Protocol.    (line  223)
* PyNumber_InPlaceSubtract (C function): Number Protocol.    (line  152)
* PyNumber_InPlaceTrueDivide (C function): Number Protocol.  (line  184)
* PyNumber_InPlaceXor (C function):      Number Protocol.    (line  239)
* PyNumber_Invert (C function):          Number Protocol.    (line  105)
* PyNumber_Long (C function):            Number Protocol.    (line  255)
* PyNumber_Lshift (C function):          Number Protocol.    (line  110)
* PyNumber_MatrixMultiply (C function):  Number Protocol.    (line   34)
* PyNumber_Multiply (C function):        Number Protocol.    (line   27)
* PyNumber_Negative (C function):        Number Protocol.    (line   88)
* PyNumber_Or (C function):              Number Protocol.    (line  138)
* PyNumber_Positive (C function):        Number Protocol.    (line   93)
* PyNumber_Power (C function):           Number Protocol.    (line   77)
* PyNumber_Remainder (C function):       Number Protocol.    (line   61)
* PyNumber_Rshift (C function):          Number Protocol.    (line  117)
* PyNumber_Subtract (C function):        Number Protocol.    (line   20)
* PyNumber_ToBase (C function):          Number Protocol.    (line  280)
* PyNumber_TrueDivide (C function):      Number Protocol.    (line   50)
* PyNumber_Xor (C function):             Number Protocol.    (line  131)
* PyNumberMethods (C type):              Number Object Structures.
                                                             (line    6)
* PyNumberMethods.nb_absolute (C member): Number Object Structures.
                                                             (line  117)
* PyNumberMethods.nb_add (C member):     Number Object Structures.
                                                             (line   70)
* PyNumberMethods.nb_and (C member):     Number Object Structures.
                                                             (line  146)
* PyNumberMethods.nb_bool (C member):    Number Object Structures.
                                                             (line  123)
* PyNumberMethods.nb_divmod (C member):  Number Object Structures.
                                                             (line   93)
* PyNumberMethods.nb_float (C member):   Number Object Structures.
                                                             (line  168)
* PyNumberMethods.nb_floor_divide (C member): Number Object Structures.
                                                             (line  234)
* PyNumberMethods.nb_index (C member):   Number Object Structures.
                                                             (line  258)
* PyNumberMethods.nb_inplace_add (C member): Number Object Structures.
                                                             (line  174)
* PyNumberMethods.nb_inplace_and (C member): Number Object Structures.
                                                             (line  216)
* PyNumberMethods.nb_inplace_floor_divide (C member): Number Object Structures.
                                                             (line  246)
* PyNumberMethods.nb_inplace_lshift (C member): Number Object Structures.
                                                             (line  204)
* PyNumberMethods.nb_inplace_matrix_multiply (C member): Number Object Structures.
                                                             (line  270)
* PyNumberMethods.nb_inplace_multiply (C member): Number Object Structures.
                                                             (line  186)
* PyNumberMethods.nb_inplace_or (C member): Number Object Structures.
                                                             (line  228)
* PyNumberMethods.nb_inplace_power (C member): Number Object Structures.
                                                             (line  198)
* PyNumberMethods.nb_inplace_remainder (C member): Number Object Structures.
                                                             (line  192)
* PyNumberMethods.nb_inplace_rshift (C member): Number Object Structures.
                                                             (line  210)
* PyNumberMethods.nb_inplace_subtract (C member): Number Object Structures.
                                                             (line  180)
* PyNumberMethods.nb_inplace_true_divide (C member): Number Object Structures.
                                                             (line  252)
* PyNumberMethods.nb_inplace_xor (C member): Number Object Structures.
                                                             (line  222)
* PyNumberMethods.nb_int (C member):     Number Object Structures.
                                                             (line  161)
* PyNumberMethods.nb_invert (C member):  Number Object Structures.
                                                             (line  128)
* PyNumberMethods.nb_lshift (C member):  Number Object Structures.
                                                             (line  134)
* PyNumberMethods.nb_matrix_multiply (C member): Number Object Structures.
                                                             (line  264)
* PyNumberMethods.nb_multiply (C member): Number Object Structures.
                                                             (line   81)
* PyNumberMethods.nb_negative (C member): Number Object Structures.
                                                             (line  105)
* PyNumberMethods.nb_or (C member):      Number Object Structures.
                                                             (line  156)
* PyNumberMethods.nb_positive (C member): Number Object Structures.
                                                             (line  111)
* PyNumberMethods.nb_power (C member):   Number Object Structures.
                                                             (line   99)
* PyNumberMethods.nb_remainder (C member): Number Object Structures.
                                                             (line   87)
* PyNumberMethods.nb_reserved (C member): Number Object Structures.
                                                             (line  166)
* PyNumberMethods.nb_rshift (C member):  Number Object Structures.
                                                             (line  140)
* PyNumberMethods.nb_subtract (C member): Number Object Structures.
                                                             (line   75)
* PyNumberMethods.nb_true_divide (C member): Number Object Structures.
                                                             (line  240)
* PyNumberMethods.nb_xor (C member):     Number Object Structures.
                                                             (line  151)
* PyObject (C type):                     Base object types and macros.
                                                             (line   14)
* PyObject_ASCII (C function):           Object Protocol.    (line  344)
* PyObject_AsFileDescriptor (C function): File Objects.      (line   33)
* PyObject_Bytes (C function):           Object Protocol.    (line  371)
* PyObject_Call (C function):            Object Calling API. (line   57)
* PyObject_CallFunction (C function):    Object Calling API. (line  108)
* PyObject_CallFunctionObjArgs (C function): Object Calling API.
                                                             (line  149)
* PyObject_CallMethod (C function):      Object Calling API. (line  127)
* PyObject_CallMethodNoArgs (C function): Object Calling API.
                                                             (line  174)
* PyObject_CallMethodObjArgs (C function): Object Calling API.
                                                             (line  162)
* PyObject_CallMethodOneArg (C function): Object Calling API.
                                                             (line  186)
* PyObject_CallNoArgs (C function):      Object Calling API. (line   73)
* PyObject_CallObject (C function):      Calling Python Functions from C.
                                                             (line   64)
* PyObject_CallObject (C function) <1>:  Object Calling API. (line   96)
* PyObject_Calloc (C function):          Object allocators.  (line   30)
* PyObject_CallOneArg (C function):      Object Calling API. (line   85)
* PyObject_CheckBuffer (C function):     Buffer-related functions.
                                                             (line    6)
* PyObject_ClearManagedDict (C function): Object Protocol.   (line  605)
* PyObject_ClearWeakRefs (C function):   Weak Reference Objects<2>.
                                                             (line  109)
* PyObject_CopyData (C function):        Buffer-related functions.
                                                             (line   80)
* PyObject_DEL (C macro):                Deprecated aliases<3>.
                                                             (line   34)
* PyObject_Del (C macro):                Deprecated aliases<3>.
                                                             (line   37)
* PyObject_DelAttr (C function):         Object Protocol.    (line  241)
* PyObject_DelAttrString (C function):   Object Protocol.    (line  247)
* PyObject_DelItem (C function):         Object Protocol.    (line  508)
* PyObject_DelItemString (C function):   Object Protocol.    (line  513)
* PyObject_Dir (C function):             Object Protocol.    (line  519)
* PyObject_Format (C function):          Object Protocol.    (line  319)
* PyObject_Free (C function):            Object allocators.  (line   58)
* PyObject_FREE (C macro):               Deprecated aliases<3>.
                                                             (line   31)
* PyObject_GC_Del (C function):          Supporting Cyclic Garbage Collection.
                                                             (line  133)
* PyObject_GC_IsFinalized (C function):  Supporting Cyclic Garbage Collection.
                                                             (line  123)
* PyObject_GC_IsTracked (C function):    Supporting Cyclic Garbage Collection.
                                                             (line  113)
* PyObject_GC_New (C macro):             Supporting Cyclic Garbage Collection.
                                                             (line   56)
* PyObject_GC_NewVar (C macro):          Supporting Cyclic Garbage Collection.
                                                             (line   61)
* PyObject_GC_Resize (C macro):          Supporting Cyclic Garbage Collection.
                                                             (line   87)
* PyObject_GC_Track (C function):        Supporting Cyclic Garbage Collection.
                                                             (line   97)
* PyObject_GC_UnTrack (C function):      Supporting Cyclic Garbage Collection.
                                                             (line  138)
* PyObject_GenericGetAttr (C function):  Object Protocol.    (line  187)
* PyObject_GenericGetDict (C function):  Object Protocol.    (line  262)
* PyObject_GenericHash (C function):     PyHash API.         (line  153)
* PyObject_GenericSetAttr (C function):  Object Protocol.    (line  229)
* PyObject_GenericSetDict (C function):  Object Protocol.    (line  278)
* PyObject_GetAIter (C function):        Object Protocol.    (line  543)
* PyObject_GetArenaAllocator (C function): Customize pymalloc Arena Allocator.
                                                             (line   26)
* PyObject_GetAttr (C function):         Object Protocol.    (line  143)
* PyObject_GetAttrString (C function):   Object Protocol.    (line  153)
* PyObject_GetBuffer (C function):       Buffer-related functions.
                                                             (line   12)
* PyObject_GetItem (C function):         Object Protocol.    (line  494)
* PyObject_GetItemData (C function):     Object Protocol.    (line  584)
* PyObject_GetIter (C function):         Object Protocol.    (line  529)
* PyObject_GetOptionalAttr (C function): Object Protocol.    (line  163)
* PyObject_GetOptionalAttrString (C function): Object Protocol.
                                                             (line  178)
* PyObject_GetTypeData (C function):     Object Protocol.    (line  554)
* PyObject_HasAttr (C function):         Object Protocol.    (line  115)
* PyObject_HasAttrString (C function):   Object Protocol.    (line  128)
* PyObject_HasAttrStringWithError (C function): Object Protocol.
                                                             (line  106)
* PyObject_HasAttrWithError (C function): Object Protocol.   (line   97)
* PyObject_Hash (C function):            Object Protocol.    (line  426)
* PyObject_HashNotImplemented (C function): Object Protocol. (line  436)
* PyObject_HEAD (C macro):               Base object types and macros.
                                                             (line   35)
* PyObject_HEAD_INIT (C macro):          Base object types and macros.
                                                             (line  127)
* PyObject_Init (C function):            Allocating Objects on the Heap.
                                                             (line   13)
* PyObject_INIT (C macro):               Deprecated aliases<3>.
                                                             (line   19)
* PyObject_INIT_VAR (C macro):           Deprecated aliases<3>.
                                                             (line   22)
* PyObject_InitVar (C function):         Allocating Objects on the Heap.
                                                             (line   20)
* PyObject_IS_GC (C function):           Supporting Cyclic Garbage Collection.
                                                             (line  105)
* PyObject_IsInstance (C function):      Object Protocol.    (line  405)
* PyObject_IsSubclass (C function):      Object Protocol.    (line  384)
* PyObject_IsTrue (C function):          Object Protocol.    (line  444)
* PyObject_Length (C function):          Object Protocol.    (line  474)
* PyObject_LengthHint (C function):      Object Protocol.    (line  483)
* PyObject_Malloc (C function):          Object allocators.  (line   21)
* PyObject_MALLOC (C macro):             Deprecated aliases<3>.
                                                             (line   25)
* PyObject_New (C macro):                Allocating Objects on the Heap.
                                                             (line   26)
* PyObject_NEW (C macro):                Deprecated aliases<3>.
                                                             (line   13)
* PyObject_NEW_VAR (C macro):            Deprecated aliases<3>.
                                                             (line   16)
* PyObject_NewVar (C macro):             Allocating Objects on the Heap.
                                                             (line   40)
* PyObject_Not (C function):             Object Protocol.    (line  450)
* PyObject_Print (C function):           Object Protocol.    (line   89)
* PyObject_Realloc (C function):         Object allocators.  (line   42)
* PyObject_REALLOC (C macro):            Deprecated aliases<3>.
                                                             (line   28)
* PyObject_Repr (C function):            Object Protocol.    (line  329)
* PyObject_RichCompare (C function):     Object Protocol.    (line  296)
* PyObject_RichCompareBool (C function): Object Protocol.    (line  308)
* PyObject_SelfIter (C function):        Object Protocol.    (line  537)
* PyObject_SetArenaAllocator (C function): Customize pymalloc Arena Allocator.
                                                             (line   31)
* PyObject_SetAttr (C function):         Object Protocol.    (line  199)
* PyObject_SetAttrString (C function):   Object Protocol.    (line  211)
* PyObject_SetItem (C function):         Object Protocol.    (line  501)
* PyObject_Size (C function):            Object Protocol.    (line  474)
* PyObject_Str (C function):             Object Protocol.    (line  357)
* PyObject_Type (C function):            Object Protocol.    (line  456)
* PyObject_TypeCheck (C function):       Object Protocol.    (line  469)
* PyObject_VAR_HEAD (C macro):           Base object types and macros.
                                                             (line   45)
* PyObject_Vectorcall (C function):      Object Calling API. (line  198)
* PyObject_VectorcallDict (C function):  Object Calling API. (line  216)
* PyObject_VectorcallMethod (C function): Object Calling API.
                                                             (line  232)
* PyObject_VisitManagedDict (C function): Object Protocol.   (line  595)
* PyObject.ob_refcnt (C member):         PyObject Slots.     (line   13)
* PyObject.ob_type (C member):           PyObject Slots.     (line   26)
* PyObjectArenaAllocator (C type):       Customize pymalloc Arena Allocator.
                                                             (line    8)
* PyODict_Check (C function):            Ordered Dictionaries.
                                                             (line   16)
* PyODict_CheckExact (C function):       Ordered Dictionaries.
                                                             (line   22)
* PyODict_Contains (C macro):            Ordered Dictionaries.
                                                             (line   79)
* PyODict_DelItem (C function):          Ordered Dictionaries.
                                                             (line   57)
* PyODict_GetItem (C macro):             Ordered Dictionaries.
                                                             (line   70)
* PyODict_GetItemString (C macro):       Ordered Dictionaries.
                                                             (line   76)
* PyODict_GetItemWithError (C macro):    Ordered Dictionaries.
                                                             (line   73)
* PyODict_New (C function):              Ordered Dictionaries.
                                                             (line   42)
* PyODict_SetItem (C function):          Ordered Dictionaries.
                                                             (line   48)
* PyODict_Size (C macro):                Ordered Dictionaries.
                                                             (line   82)
* PyODict_SIZE (C macro):                Ordered Dictionaries.
                                                             (line   85)
* PyODict_Type (C var):                  Ordered Dictionaries.
                                                             (line   11)
* PyODictItems_Type (C var):             Ordered Dictionaries.
                                                             (line   37)
* PyODictIter_Type (C var):              Other Iterator Objects.
                                                             (line   48)
* PyODictKeys_Type (C var):              Ordered Dictionaries.
                                                             (line   28)
* PyODictValues_Type (C var):            Ordered Dictionaries.
                                                             (line   32)
* PyOS_AfterFork (C function):           Operating System Utilities.
                                                             (line   79)
* PyOS_AfterFork_Child (C function):     Operating System Utilities.
                                                             (line   56)
* PyOS_AfterFork_Parent (C function):    Operating System Utilities.
                                                             (line   42)
* PyOS_BeforeFork (C function):          Operating System Utilities.
                                                             (line   29)
* PyOS_CheckStack (C function):          Operating System Utilities.
                                                             (line   89)
* PyOS_double_to_string (C function):    String conversion and formatting.
                                                             (line  118)
* PyOS_FSPath (C function):              Operating System Utilities.
                                                             (line    6)
* PyOS_getsig (C function):              Operating System Utilities.
                                                             (line  103)
* PyOS_InputHook (C var):                The Very High Level Layer.
                                                             (line  144)
* PyOS_InterruptOccurred (C function):   Operating System Utilities.
                                                             (line  115)
* PyOS_mystricmp (C function):           String conversion and formatting.
                                                             (line  172)
* PyOS_mystrnicmp (C function):          String conversion and formatting.
                                                             (line  172)
* PyOS_ReadlineFunctionPointer (C var):  The Very High Level Layer.
                                                             (line  156)
* PyOS_setsig (C function):              Operating System Utilities.
                                                             (line  108)
* PyOS_sighandler_t (C type):            Operating System Utilities.
                                                             (line  100)
* PyOS_snprintf (C function):            String conversion and formatting.
                                                             (line    8)
* PyOS_stricmp (C function):             String conversion and formatting.
                                                             (line  191)
* PyOS_string_to_double (C function):    String conversion and formatting.
                                                             (line   85)
* PyOS_strnicmp (C function):            String conversion and formatting.
                                                             (line  191)
* PyOS_strtol (C function):              String conversion and formatting.
                                                             (line   72)
* PyOS_strtoul (C function):             String conversion and formatting.
                                                             (line   50)
* PyOS_vsnprintf (C function):           String conversion and formatting.
                                                             (line   14)
* PyPickleBuffer_Check (C function):     Pickle buffer objects.
                                                             (line   18)
* PyPickleBuffer_FromObject (C function): Pickle buffer objects.
                                                             (line   23)
* PyPickleBuffer_GetBuffer (C function): Pickle buffer objects.
                                                             (line   37)
* PyPickleBuffer_Release (C function):   Pickle buffer objects.
                                                             (line   51)
* PyPickleBuffer_Type (C var):           Pickle buffer objects.
                                                             (line   12)
* PyPreConfig (C type):                  PyPreConfig.        (line    6)
* PyPreConfig_InitIsolatedConfig (C function): PyPreConfig.  (line   18)
* PyPreConfig_InitPythonConfig (C function): PyPreConfig.    (line   12)
* PyPreConfig.allocator (C member):      PyPreConfig.        (line   26)
* PyPreConfig.coerce_c_locale (C member): PyPreConfig.       (line   82)
* PyPreConfig.coerce_c_locale_warn (C member): PyPreConfig.  (line   93)
* PyPreConfig.configure_locale (C member): PyPreConfig.      (line   71)
* PyPreConfig.dev_mode (C member):       PyPreConfig.        (line   99)
* PyPreConfig.isolated (C member):       PyPreConfig.        (line  106)
* PyPreConfig.legacy_windows_fs_encoding (C member): PyPreConfig.
                                                             (line  112)
* PyPreConfig.parse_argv (C member):     PyPreConfig.        (line  131)
* PyPreConfig.use_environment (C member): PyPreConfig.       (line  140)
* PyPreConfig.utf8_mode (C member):      PyPreConfig.        (line  147)
* PyProperty_Type (C var):               Descriptor Objects. (line    9)
* PyRange_Check (C function):            Range Objects.      (line   10)
* PyRange_Type (C var):                  Range Objects.      (line    6)
* PyRangeIter_Type (C var):              Other Iterator Objects.
                                                             (line   24)
* PyRefTracer (C type):                  Reference tracing.  (line    8)
* PyRefTracer_CREATE (C var):            Reference tracing.  (line   21)
* PyRefTracer_DESTROY (C var):           Reference tracing.  (line   26)
* PyRefTracer_GetTracer (C function):    Reference tracing.  (line   49)
* PyRefTracer_SetTracer (C function):    Reference tracing.  (line   31)
* PyReversed_Type (C var):               Builtin Iterator Types.
                                                             (line   23)
* PyRun_AnyFile (C function):            The Very High Level Layer.
                                                             (line   25)
* PyRun_AnyFileEx (C function):          The Very High Level Layer.
                                                             (line   37)
* PyRun_AnyFileExFlags (C function):     The Very High Level Layer.
                                                             (line   43)
* PyRun_AnyFileFlags (C function):       The Very High Level Layer.
                                                             (line   31)
* PyRun_File (C function):               The Very High Level Layer.
                                                             (line  199)
* PyRun_FileEx (C function):             The Very High Level Layer.
                                                             (line  205)
* PyRun_FileExFlags (C function):        The Very High Level Layer.
                                                             (line  219)
* PyRun_FileFlags (C function):          The Very High Level Layer.
                                                             (line  212)
* PyRun_InteractiveLoop (C function):    The Very High Level Layer.
                                                             (line  128)
* PyRun_InteractiveLoopFlags (C function): The Very High Level Layer.
                                                             (line  135)
* PyRun_InteractiveOne (C function):     The Very High Level Layer.
                                                             (line  114)
* PyRun_InteractiveOneFlags (C function): The Very High Level Layer.
                                                             (line  121)
* PyRun_InteractiveOneObject (C function): The Very High Level Layer.
                                                             (line  100)
* PyRun_SimpleFile (C function):         The Very High Level Layer.
                                                             (line   75)
* PyRun_SimpleFileEx (C function):       The Very High Level Layer.
                                                             (line   81)
* PyRun_SimpleFileExFlags (C function):  The Very High Level Layer.
                                                             (line   87)
* PyRun_SimpleString (C function):       The Very High Level Layer.
                                                             (line   55)
* PyRun_SimpleStringFlags (C function):  The Very High Level Layer.
                                                             (line   61)
* PyRun_String (C function):             The Very High Level Layer.
                                                             (line  180)
* PyRun_StringFlags (C function):        The Very High Level Layer.
                                                             (line  186)
* PySendResult (C type):                 Iterator Protocol.  (line   55)
* PySeqIter_Check (C function):          Iterator Objects.   (line   18)
* PySeqIter_New (C function):            Iterator Objects.   (line   23)
* PySeqIter_Type (C var):                Iterator Objects.   (line   12)
* PySequence_Check (C function):         Sequence Protocol.  (line    6)
* PySequence_Concat (C function):        Sequence Protocol.  (line   21)
* PySequence_Contains (C function):      Sequence Protocol.  (line   99)
* PySequence_Count (C function):         Sequence Protocol.  (line   92)
* PySequence_DelItem (C function):       Sequence Protocol.  (line   75)
* PySequence_DelSlice (C function):      Sequence Protocol.  (line   86)
* PySequence_Fast (C function):          Sequence Protocol.  (line  128)
* PySequence_Fast_GET_ITEM (C function): Sequence Protocol.  (line  152)
* PySequence_Fast_GET_SIZE (C function): Sequence Protocol.  (line  143)
* PySequence_Fast_ITEMS (C function):    Sequence Protocol.  (line  158)
* PySequence_GetItem (C function):       Reference Count Details.
                                                             (line  117)
* PySequence_GetItem (C function) <1>:   Sequence Protocol.  (line   51)
* PySequence_GetSlice (C function):      Sequence Protocol.  (line   57)
* PySequence_Index (C function):         Sequence Protocol.  (line  105)
* PySequence_InPlaceConcat (C function): Sequence Protocol.  (line   35)
* PySequence_InPlaceRepeat (C function): Sequence Protocol.  (line   43)
* PySequence_ITEM (C function):          Sequence Protocol.  (line  169)
* PySequence_Length (C function):        Sequence Protocol.  (line   14)
* PySequence_List (C function):          Sequence Protocol.  (line  111)
* PySequence_Repeat (C function):        Sequence Protocol.  (line   28)
* PySequence_SetItem (C function):       Sequence Protocol.  (line   64)
* PySequence_SetSlice (C function):      Sequence Protocol.  (line   80)
* PySequence_Size (C function):          Sequence Protocol.  (line   14)
* PySequence_Tuple (C function):         Sequence Protocol.  (line  118)
* PySequenceMethods (C type):            Sequence Object Structures.
                                                             (line    6)
* PySequenceMethods.sq_ass_item (C member): Sequence Object Structures.
                                                             (line   62)
* PySequenceMethods.sq_concat (C member): Sequence Object Structures.
                                                             (line   22)
* PySequenceMethods.sq_contains (C member): Sequence Object Structures.
                                                             (line   75)
* PySequenceMethods.sq_inplace_concat (C member): Sequence Object Structures.
                                                             (line   86)
* PySequenceMethods.sq_inplace_repeat (C member): Sequence Object Structures.
                                                             (line  100)
* PySequenceMethods.sq_item (C member):  Sequence Object Structures.
                                                             (line   43)
* PySequenceMethods.sq_length (C member): Sequence Object Structures.
                                                             (line   11)
* PySequenceMethods.sq_repeat (C member): Sequence Object Structures.
                                                             (line   32)
* PySet_Add (C function):                Set Objects.        (line  119)
* PySet_Check (C function):              Set Objects.        (line   44)
* PySet_CheckExact (C function):         Set Objects.        (line   60)
* PySet_Clear (C function):              Set Objects.        (line  152)
* PySet_Contains (C function):           Set Objects.        (line  110)
* PySet_Discard (C function):            Set Objects.        (line  134)
* PySet_GET_SIZE (C function):           Set Objects.        (line  106)
* PySet_New (C function):                Set Objects.        (line   78)
* PySet_Pop (C function):                Set Objects.        (line  144)
* PySet_Size (C function):               Set Objects.        (line   98)
* PySet_Type (C var):                    Set Objects.        (line   31)
* PySetIter_Type (C var):                Other Iterator Objects.
                                                             (line   18)
* PySetObject (C type):                  Set Objects.        (line   19)
* PySignal_SetWakeupFd (C function):     Signal Handling<2>. (line   79)
* PySlice_AdjustIndices (C function):    Slice Objects.      (line   99)
* PySlice_Check (C function):            Slice Objects.      (line   11)
* PySlice_GetIndices (C function):       Slice Objects.      (line   28)
* PySlice_GetIndicesEx (C function):     Slice Objects.      (line   44)
* PySlice_New (C function):              Slice Objects.      (line   16)
* PySlice_Type (C var):                  Slice Objects.      (line    6)
* PySlice_Unpack (C function):           Slice Objects.      (line   86)
* PyState_AddModule (C function):        Module lookup.      (line   25)
* PyState_FindModule (C function):       Module lookup.      (line   15)
* PyState_RemoveModule (C function):     Module lookup.      (line   49)
* PyStaticMethod_New (C function):       Built-in descriptors.
                                                             (line   38)
* PyStaticMethod_Type (C var):           Built-in descriptors.
                                                             (line   33)
* PyStatus (C type):                     PyStatus.           (line    6)
* PyStatus_Error (C function):           PyStatus.           (line   34)
* PyStatus_Exception (C function):       PyStatus.           (line   51)
* PyStatus_Exit (C function):            PyStatus.           (line   45)
* PyStatus_IsError (C function):         PyStatus.           (line   57)
* PyStatus_IsExit (C function):          PyStatus.           (line   61)
* PyStatus_NoMemory (C function):        PyStatus.           (line   41)
* PyStatus_Ok (C function):              PyStatus.           (line   30)
* PyStatus.err_msg (C member):           PyStatus.           (line   20)
* PyStatus.exitcode (C member):          PyStatus.           (line   16)
* PyStatus.func (C member):              PyStatus.           (line   24)
* PyStructSequence_Desc (C type):        Struct Sequence Objects.
                                                             (line   33)
* PyStructSequence_Desc.doc (C member):  Struct Sequence Objects.
                                                             (line   42)
* PyStructSequence_Desc.fields (C member): Struct Sequence Objects.
                                                             (line   46)
* PyStructSequence_Desc.n_in_sequence (C member): Struct Sequence Objects.
                                                             (line   51)
* PyStructSequence_Desc.name (C member): Struct Sequence Objects.
                                                             (line   37)
* PyStructSequence_Field (C type):       Struct Sequence Objects.
                                                             (line   56)
* PyStructSequence_Field.doc (C member): Struct Sequence Objects.
                                                             (line   70)
* PyStructSequence_Field.name (C member): Struct Sequence Objects.
                                                             (line   64)
* PyStructSequence_GET_ITEM (C function): Struct Sequence Objects.
                                                             (line   97)
* PyStructSequence_GetItem (C function): Struct Sequence Objects.
                                                             (line   88)
* PyStructSequence_InitType (C function): Struct Sequence Objects.
                                                             (line   20)
* PyStructSequence_InitType2 (C function): Struct Sequence Objects.
                                                             (line   25)
* PyStructSequence_New (C function):     Struct Sequence Objects.
                                                             (line   80)
* PyStructSequence_NewType (C function): Struct Sequence Objects.
                                                             (line   11)
* PyStructSequence_SET_ITEM (C function): Struct Sequence Objects.
                                                             (line  117)
* PyStructSequence_SetItem (C function): Struct Sequence Objects.
                                                             (line  105)
* PyStructSequence_UnnamedField (C var): Struct Sequence Objects.
                                                             (line   74)
* PySuper_Type (C var):                  Built-in descriptors.
                                                             (line    6)
* PySys_AddAuditHook (C function):       System Functions.   (line  116)
* PySys_Audit (C function):              System Functions.   (line   75)
* PySys_AuditTuple (C function):         System Functions.   (line  108)
* PySys_FormatStderr (C function):       System Functions.   (line   60)
* PySys_FormatStdout (C function):       System Functions.   (line   52)
* PySys_GetObject (C function):          System Functions.   (line   11)
* PySys_GetXOptions (C function):        System Functions.   (line   67)
* PySys_ResetWarnOptions (C function):   System Functions.   (line   22)
* PySys_SetArgv (C function):            Process-wide parameters.
                                                             (line  268)
* PySys_SetArgvEx (C function):          Process-wide parameters.
                                                             (line  216)
* PySys_SetObject (C function):          System Functions.   (line   16)
* PySys_WriteStderr (C function):        System Functions.   (line   47)
* PySys_WriteStdout (C function):        System Functions.   (line   30)
* Python 3000:                           Glossary.           (line 1396)
* Python Editor:                         IDLE — Python editor and shell<2>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 0007#documentation-strings: Documentation<27>.
                                                             (line   35)
* Python Enhancement Proposals; PEP 0249#threadsafety: Module constants.
                                                             (line  108)
* Python Enhancement Proposals; PEP 0453#recommendations-for-downstream-distributors: Bootstrapping pip By Default.
                                                             (line   39)
* Python Enhancement Proposals; PEP 0477#disabling-ensurepip-by-downstream-distributors: Bootstrapping pip By Default<2>.
                                                             (line   29)
* Python Enhancement Proposals; PEP 0564#annex-clocks-resolution-in-python: PEP 564 New Time Functions With Nanosecond Resolution.
                                                             (line   26)
* Python Enhancement Proposals; PEP 0626#out-of-process-debuggers-and-profilers: Code Objects<2>.
                                                             (line  104)
* Python Enhancement Proposals; PEP 0632#migration-advice: Summary – Release highlights.
                                                             (line  111)
* Python Enhancement Proposals; PEP 0683: Reference Counting.
                                                             (line   61)
* Python Enhancement Proposals; PEP 1:   New Development Process.
                                                             (line   67)
* Python Enhancement Proposals; PEP 1 <1>: New Development Process.
                                                             (line   82)
* Python Enhancement Proposals; PEP 1 <2>: Glossary.         (line 1362)
* Python Enhancement Proposals; PEP 100: Unicode<2>.         (line   15)
* Python Enhancement Proposals; PEP 11:  Support for mobile platforms.
                                                             (line    6)
* Python Enhancement Proposals; PEP 11 <1>: Support for mobile platforms.
                                                             (line   15)
* Python Enhancement Proposals; PEP 11 <2>: Build Changes.   (line    6)
* Python Enhancement Proposals; PEP 11 <3>: Build Changes.   (line   10)
* Python Enhancement Proposals; PEP 11 <4>: Build Changes.   (line   14)
* Python Enhancement Proposals; PEP 11 <5>: Build Changes.   (line   17)
* Python Enhancement Proposals; PEP 11 <6>: Build Changes<3>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 11 <7>: PEP 538 Legacy C Locale Coercion.
                                                             (line   19)
* Python Enhancement Proposals; PEP 11 <8>: Unsupported Operating Systems.
                                                             (line    6)
* Python Enhancement Proposals; PEP 11 <9>: Library Changes. (line   15)
* Python Enhancement Proposals; PEP 11 <10>: Build<31>.      (line   56)
* Python Enhancement Proposals; PEP 11 <11>: Build<31>.      (line  107)
* Python Enhancement Proposals; PEP 11 <12>: Build<69>.      (line   14)
* Python Enhancement Proposals; PEP 11 <13>: Build Requirements.
                                                             (line   51)
* Python Enhancement Proposals; PEP 11 <14>: Using Python on Windows.
                                                             (line   18)
* Python Enhancement Proposals; PEP 11 <15>: Other Platforms.
                                                             (line    8)
* Python Enhancement Proposals; PEP 11 <16>: Useful macros.  (line  101)
* Python Enhancement Proposals; PEP 11#tier-2: Summary – Release Highlights.
                                                             (line  139)
* Python Enhancement Proposals; PEP 11#tier-3: Summary – Release Highlights.
                                                             (line  134)
* Python Enhancement Proposals; PEP 11#tier-3 <1>: Summary – Release Highlights.
                                                             (line  137)
* Python Enhancement Proposals; PEP 11#tier-3 <2>: Build Changes<3>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 201: New Development Process.
                                                             (line   86)
* Python Enhancement Proposals; PEP 205: PEP 205 Weak References.
                                                             (line   82)
* Python Enhancement Proposals; PEP 205 <1>: weakref — Weak references.
                                                             (line  351)
* Python Enhancement Proposals; PEP 207: PEP 207 Rich Comparisons.
                                                             (line   71)
* Python Enhancement Proposals; PEP 207 <1>: PEP 207 Rich Comparisons.
                                                             (line   77)
* Python Enhancement Proposals; PEP 208: PEP 208 New Coercion Model.
                                                             (line   29)
* Python Enhancement Proposals; PEP 217: PEP 217 Interactive Display Hook.
                                                             (line   27)
* Python Enhancement Proposals; PEP 218: PEP 218 Built-In Set Objects.
                                                             (line   50)
* Python Enhancement Proposals; PEP 218 <1>: Other Language Changes<17>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 218 <2>: PEP 218 A Standard Set Datatype.
                                                             (line   81)
* Python Enhancement Proposals; PEP 227: PEP 227 Nested Scopes.
                                                             (line   96)
* Python Enhancement Proposals; PEP 227 <1>: PEP 227 Nested Scopes<2>.
                                                             (line   96)
* Python Enhancement Proposals; PEP 227 <2>: Module Contents<4>.
                                                             (line   14)
* Python Enhancement Proposals; PEP 229: PEP 229 New Build System.
                                                             (line   39)
* Python Enhancement Proposals; PEP 230: PEP 230 Warning Framework.
                                                             (line   73)
* Python Enhancement Proposals; PEP 232: PEP 232 Function Attributes.
                                                             (line   36)
* Python Enhancement Proposals; PEP 234: PEP 234 Iterators.  (line  124)
* Python Enhancement Proposals; PEP 235: Introduction<12>.   (line   51)
* Python Enhancement Proposals; PEP 236: PEP 227 Nested Scopes<2>.
                                                             (line   87)
* Python Enhancement Proposals; PEP 236 <1>: PEP 227 Nested Scopes<2>.
                                                             (line   88)
* Python Enhancement Proposals; PEP 236 <2>: PEP 236 __future__ Directives.
                                                             (line   29)
* Python Enhancement Proposals; PEP 236 <3>: Future statements.
                                                             (line   84)
* Python Enhancement Proposals; PEP 236 <4>: Module Contents<4>.
                                                             (line  103)
* Python Enhancement Proposals; PEP 237: Integers.           (line    6)
* Python Enhancement Proposals; PEP 237 <1>: PEP 237 Unifying Long Integers and Integers.
                                                             (line   22)
* Python Enhancement Proposals; PEP 237 <2>: Other Language Changes<17>.
                                                             (line   18)
* Python Enhancement Proposals; PEP 237 <3>: PEP 237 Unifying Long Integers and Integers<2>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 237 <4>: printf-style String Formatting.
                                                             (line  189)
* Python Enhancement Proposals; PEP 237 <5>: printf-style Bytes Formatting.
                                                             (line  189)
* Python Enhancement Proposals; PEP 238: Integers.           (line   10)
* Python Enhancement Proposals; PEP 238 <1>: PEP 238 Changing the Division Operator.
                                                             (line   21)
* Python Enhancement Proposals; PEP 238 <2>: PEP 238 Changing the Division Operator.
                                                             (line   27)
* Python Enhancement Proposals; PEP 238 <3>: PEP 238 Changing the Division Operator.
                                                             (line   68)
* Python Enhancement Proposals; PEP 238 <4>: Module Contents<4>.
                                                             (line   22)
* Python Enhancement Proposals; PEP 238 <5>: Glossary.       (line  606)
* Python Enhancement Proposals; PEP 241: PEP 241 Metadata in Python Packages.
                                                             (line   16)
* Python Enhancement Proposals; PEP 241 <1>: PEP 241 Metadata in Python Packages.
                                                             (line   29)
* Python Enhancement Proposals; PEP 241 <2>: PEP 241 Metadata in Python Packages.
                                                             (line   36)
* Python Enhancement Proposals; PEP 243: PEP 241 Metadata in Python Packages.
                                                             (line   40)
* Python Enhancement Proposals; PEP 246: Documentation<26>.  (line   48)
* Python Enhancement Proposals; PEP 246 <1>: PrepareProtocol objects.
                                                             (line    8)
* Python Enhancement Proposals; PEP 247: hmac<3>.            (line   20)
* Python Enhancement Proposals; PEP 249: sqlite3<2>.         (line   11)
* Python Enhancement Proposals; PEP 249 <1>: The sqlite3 package.
                                                             (line   18)
* Python Enhancement Proposals; PEP 249 <2>: The sqlite3 package.
                                                             (line  110)
* Python Enhancement Proposals; PEP 249 <3>: Library<53>.    (line  123)
* Python Enhancement Proposals; PEP 249 <4>: Library<68>.    (line  296)
* Python Enhancement Proposals; PEP 249 <5>: sqlite3 — DB-API 2 0 interface for SQLite databases.
                                                             (line   16)
* Python Enhancement Proposals; PEP 249 <6>: sqlite3 — DB-API 2 0 interface for SQLite databases.
                                                             (line   43)
* Python Enhancement Proposals; PEP 249 <7>: Module functions.
                                                             (line   72)
* Python Enhancement Proposals; PEP 249 <8>: Connection objects.
                                                             (line  733)
* Python Enhancement Proposals; PEP 249 <9>: Connection objects.
                                                             (line  736)
* Python Enhancement Proposals; PEP 249 <10>: Connection objects.
                                                             (line  748)
* Python Enhancement Proposals; PEP 249 <11>: Exceptions<7>. (line    6)
* Python Enhancement Proposals; PEP 249 <12>: How to use placeholders to bind values in SQL queries.
                                                             (line   53)
* Python Enhancement Proposals; PEP 249 <13>: Transaction control via the autocommit attribute.
                                                             (line   10)
* Python Enhancement Proposals; PEP 249 <14>: Transaction control via the autocommit attribute.
                                                             (line   30)
* Python Enhancement Proposals; PEP 252: Related Links.      (line   17)
* Python Enhancement Proposals; PEP 252 <1>: Related Links.  (line   17)
* Python Enhancement Proposals; PEP 252 <2>: Implementing Descriptors.
                                                             (line   26)
* Python Enhancement Proposals; PEP 253: Old and New Classes.
                                                             (line   28)
* Python Enhancement Proposals; PEP 253 <1>: Multiple Inheritance The Diamond Rule.
                                                             (line    8)
* Python Enhancement Proposals; PEP 253 <2>: Related Links.  (line   17)
* Python Enhancement Proposals; PEP 253 <3>: Related Links.  (line   19)
* Python Enhancement Proposals; PEP 253 <4>: Related Links.  (line   21)
* Python Enhancement Proposals; PEP 255: PEP 255 Simple Generators.
                                                             (line   45)
* Python Enhancement Proposals; PEP 255 <1>: PEP 255 Simple Generators.
                                                             (line  131)
* Python Enhancement Proposals; PEP 255 <2>: PEP 255 Simple Generators<2>.
                                                             (line   43)
* Python Enhancement Proposals; PEP 255 <3>: PEP 255 Simple Generators<2>.
                                                             (line  129)
* Python Enhancement Proposals; PEP 255 <4>: Yield expressions.
                                                             (line   90)
* Python Enhancement Proposals; PEP 255 <5>: Module Contents<4>.
                                                             (line   18)
* Python Enhancement Proposals; PEP 261: Unicode Changes.    (line   18)
* Python Enhancement Proposals; PEP 261 <1>: Unicode Changes.
                                                             (line   61)
* Python Enhancement Proposals; PEP 263: Other Language Changes<16>.
                                                             (line   98)
* Python Enhancement Proposals; PEP 263 <1>: PEP 263 Source Code Encodings.
                                                             (line   29)
* Python Enhancement Proposals; PEP 263 <2>: Core and Builtins<79>.
                                                             (line   30)
* Python Enhancement Proposals; PEP 263 <3>: Introduction<12>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 263 <4>: Tokenizing Input.
                                                             (line   34)
* Python Enhancement Proposals; PEP 263 <5>: Tokenizing Input.
                                                             (line   85)
* Python Enhancement Proposals; PEP 263 <6>: Unicode Literals in Python Source Code.
                                                             (line   48)
* Python Enhancement Proposals; PEP 264: Other Changes and Fixes<3>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 273: PEP 273 Importing Modules from ZIP Archives.
                                                             (line   41)
* Python Enhancement Proposals; PEP 273 <1>: PEP 273 Importing Modules from ZIP Archives.
                                                             (line   44)
* Python Enhancement Proposals; PEP 273 <2>: zipimport — Import modules from Zip archives.
                                                             (line   44)
* Python Enhancement Proposals; PEP 273 <3>: zipimport — Import modules from Zip archives.
                                                             (line   47)
* Python Enhancement Proposals; PEP 274: New Syntax.         (line   38)
* Python Enhancement Proposals; PEP 277: PEP 277 Unicode file name support for Windows NT.
                                                             (line   32)
* Python Enhancement Proposals; PEP 278: PEP 278 Universal Newline Support.
                                                             (line   33)
* Python Enhancement Proposals; PEP 278 <1>: Glossary.       (line 1743)
* Python Enhancement Proposals; PEP 279: PEP 279 enumerate.  (line   27)
* Python Enhancement Proposals; PEP 282: PEP 282 The logging Package.
                                                             (line  104)
* Python Enhancement Proposals; PEP 282 <1>: PEP 282 The logging Package.
                                                             (line  110)
* Python Enhancement Proposals; PEP 282 <2>: Archiving operations.
                                                             (line   46)
* Python Enhancement Proposals; PEP 282 <3>: Integration with the warnings module.
                                                             (line   36)
* Python Enhancement Proposals; PEP 285: PEP 285 A Boolean Type.
                                                             (line   47)
* Python Enhancement Proposals; PEP 285 <1>: PEP 285 A Boolean Type.
                                                             (line   70)
* Python Enhancement Proposals; PEP 288: PEP 342 New Generator Features.
                                                             (line  146)
* Python Enhancement Proposals; PEP 289: PEP 289 Generator Expressions.
                                                             (line   55)
* Python Enhancement Proposals; PEP 289 <1>: Other Language Changes<17>.
                                                             (line   15)
* Python Enhancement Proposals; PEP 289 <2>: Python documentation.
                                                             (line   12)
* Python Enhancement Proposals; PEP 292: PEP 292 Simpler String Substitutions.
                                                             (line   45)
* Python Enhancement Proposals; PEP 292 <1>: Template strings.
                                                             (line    6)
* Python Enhancement Proposals; PEP 293: PEP 293 Codec Error Handling Callbacks.
                                                             (line   33)
* Python Enhancement Proposals; PEP 3000: Python 3 0.        (line   43)
* Python Enhancement Proposals; PEP 301: PEP 301 Package Index and Metadata for Distutils.
                                                             (line   45)
* Python Enhancement Proposals; PEP 302: Using importlib as the Implementation of Import.
                                                             (line   13)
* Python Enhancement Proposals; PEP 302 <1>: Visible Changes.
                                                             (line   18)
* Python Enhancement Proposals; PEP 302 <2>: Porting Python code.
                                                             (line   71)
* Python Enhancement Proposals; PEP 302 <3>: New Improved and Deprecated Modules<2>.
                                                             (line  106)
* Python Enhancement Proposals; PEP 302 <4>: New Improved and Removed Modules.
                                                             (line  288)
* Python Enhancement Proposals; PEP 302 <5>: PEP 273 Importing Modules from ZIP Archives.
                                                             (line   46)
* Python Enhancement Proposals; PEP 302 <6>: PEP 302 New Import Hooks.
                                                             (line   13)
* Python Enhancement Proposals; PEP 302 <7>: PEP 302 New Import Hooks.
                                                             (line   38)
* Python Enhancement Proposals; PEP 302 <8>: PEP 302 New Import Hooks.
                                                             (line   62)
* Python Enhancement Proposals; PEP 302 <9>: The import system.
                                                             (line   41)
* Python Enhancement Proposals; PEP 302 <10>: References.    (line   10)
* Python Enhancement Proposals; PEP 302 <11>: Built-in Functions.
                                                             (line 2181)
* Python Enhancement Proposals; PEP 302 <12>: linecache — Random access to text lines.
                                                             (line   31)
* Python Enhancement Proposals; PEP 302 <13>: sys — System-specific parameters and functions.
                                                             (line 1367)
* Python Enhancement Proposals; PEP 302 <14>: sys — System-specific parameters and functions.
                                                             (line 1377)
* Python Enhancement Proposals; PEP 302 <15>: zipimport — Import modules from Zip archives.
                                                             (line   49)
* Python Enhancement Proposals; PEP 302 <16>: pkgutil — Package extension utility.
                                                             (line   64)
* Python Enhancement Proposals; PEP 302 <17>: pkgutil — Package extension utility.
                                                             (line   83)
* Python Enhancement Proposals; PEP 302 <18>: pkgutil — Package extension utility.
                                                             (line   98)
* Python Enhancement Proposals; PEP 302 <19>: pkgutil — Package extension utility.
                                                             (line  121)
* Python Enhancement Proposals; PEP 302 <20>: pkgutil — Package extension utility.
                                                             (line  142)
* Python Enhancement Proposals; PEP 302 <21>: pkgutil — Package extension utility.
                                                             (line  181)
* Python Enhancement Proposals; PEP 302 <22>: runpy — Locating and executing Python modules.
                                                             (line   31)
* Python Enhancement Proposals; PEP 302 <23>: Introduction<12>.
                                                             (line   59)
* Python Enhancement Proposals; PEP 302 <24>: importlib abc – Abstract base classes related to import.
                                                             (line   92)
* Python Enhancement Proposals; PEP 302 <25>: importlib abc – Abstract base classes related to import.
                                                             (line  177)
* Python Enhancement Proposals; PEP 302 <26>: importlib abc – Abstract base classes related to import.
                                                             (line  202)
* Python Enhancement Proposals; PEP 302 <27>: importlib abc – Abstract base classes related to import.
                                                             (line  274)
* Python Enhancement Proposals; PEP 302 <28>: Glossary.      (line 1019)
* Python Enhancement Proposals; PEP 305: PEP 305 Comma-separated Files.
                                                             (line   42)
* Python Enhancement Proposals; PEP 305 <1>: csv — CSV File Reading and Writing.
                                                             (line   38)
* Python Enhancement Proposals; PEP 307: PEP 307 Pickle Enhancements.
                                                             (line    8)
* Python Enhancement Proposals; PEP 307 <1>: PEP 307 Pickle Enhancements.
                                                             (line   30)
* Python Enhancement Proposals; PEP 307 <2>: PEP 307 Pickle Enhancements.
                                                             (line   42)
* Python Enhancement Proposals; PEP 307 <3>: Data stream format.
                                                             (line   32)
* Python Enhancement Proposals; PEP 308: PEP 308 Conditional Expressions.
                                                             (line   72)
* Python Enhancement Proposals; PEP 308 <1>: PEP 308 Conditional Expressions.
                                                             (line   78)
* Python Enhancement Proposals; PEP 308 <2>: Conditional expressions.
                                                             (line   17)
* Python Enhancement Proposals; PEP 309: PEP 309 Partial Function Application.
                                                             (line   73)
* Python Enhancement Proposals; PEP 3100: Python 3 0.        (line   44)
* Python Enhancement Proposals; PEP 3101: PEP 3101 A New Approach To String Formatting.
                                                             (line    3)
* Python Enhancement Proposals; PEP 3101 <1>: PEP 3101 A New Approach To String Formatting.
                                                             (line    8)
* Python Enhancement Proposals; PEP 3101 <2>: PEP 3101 Advanced String Formatting.
                                                             (line  162)
* Python Enhancement Proposals; PEP 3101 <3>: Custom string formatting.
                                                             (line    8)
* Python Enhancement Proposals; PEP 3101 <4>: Custom string formatting.
                                                             (line   60)
* Python Enhancement Proposals; PEP 3102: New Syntax.        (line   13)
* Python Enhancement Proposals; PEP 3104: New Syntax.        (line   24)
* Python Enhancement Proposals; PEP 3104 <1>: The nonlocal statement.
                                                             (line   25)
* Python Enhancement Proposals; PEP 3105: Print Is A Function.
                                                             (line    8)
* Python Enhancement Proposals; PEP 3105 <1>: PEP 3105 print As a Function.
                                                             (line   35)
* Python Enhancement Proposals; PEP 3105 <2>: Module Contents<4>.
                                                             (line   35)
* Python Enhancement Proposals; PEP 3106: PEP 3106 Dictionary Views.
                                                             (line   58)
* Python Enhancement Proposals; PEP 3107: PEP 563 Postponed Evaluation of Annotations.
                                                             (line    7)
* Python Enhancement Proposals; PEP 3107 <1>: PEP 484 - Type Hints.
                                                             (line    7)
* Python Enhancement Proposals; PEP 3107 <2>: New Syntax.    (line    6)
* Python Enhancement Proposals; PEP 3107 <3>: Function Annotations.
                                                             (line    7)
* Python Enhancement Proposals; PEP 3107 <4>: Function definitions.
                                                             (line  147)
* Python Enhancement Proposals; PEP 3108: Library Changes.   (line    7)
* Python Enhancement Proposals; PEP 3108 <1>: Library Changes.
                                                             (line   17)
* Python Enhancement Proposals; PEP 3108 <2>: Library Changes.
                                                             (line   94)
* Python Enhancement Proposals; PEP 3109: Changed Syntax.    (line    6)
* Python Enhancement Proposals; PEP 3109 <1>: Changes To Exceptions.
                                                             (line   29)
* Python Enhancement Proposals; PEP 3110: Changed Syntax.    (line   16)
* Python Enhancement Proposals; PEP 3110 <1>: Changes To Exceptions.
                                                             (line   35)
* Python Enhancement Proposals; PEP 3110 <2>: PEP 3110 Exception-Handling Changes.
                                                             (line   48)
* Python Enhancement Proposals; PEP 3111: Builtins.          (line   12)
* Python Enhancement Proposals; PEP 3112: PEP 3112 Byte Literals.
                                                             (line   76)
* Python Enhancement Proposals; PEP 3112 <1>: Module Contents<4>.
                                                             (line   39)
* Python Enhancement Proposals; PEP 3113: Removed Syntax.    (line    6)
* Python Enhancement Proposals; PEP 3114: Operators And Special Methods.
                                                             (line   19)
* Python Enhancement Proposals; PEP 3115: types<7>.          (line   10)
* Python Enhancement Proposals; PEP 3115 <1>: Changed Syntax.
                                                             (line   18)
* Python Enhancement Proposals; PEP 3115 <2>: Preparing the class namespace.
                                                             (line   21)
* Python Enhancement Proposals; PEP 3115 <3>: Class definitions.
                                                             (line   83)
* Python Enhancement Proposals; PEP 3115 <4>: Dynamic Type Creation.
                                                             (line   54)
* Python Enhancement Proposals; PEP 3115 <5>: Function and class definitions.
                                                             (line  181)
* Python Enhancement Proposals; PEP 3116: Optimizations<12>. (line    8)
* Python Enhancement Proposals; PEP 3116 <1>: PEP 3116 New I/O Library.
                                                             (line   72)
* Python Enhancement Proposals; PEP 3116 <2>: Glossary.      (line 1743)
* Python Enhancement Proposals; PEP 3118: Pickle protocol 5 with out-of-band data buffers.
                                                             (line   13)
* Python Enhancement Proposals; PEP 3118 <1>: PEP 3118 New memoryview implementation and buffer protocol documentation.
                                                             (line    6)
* Python Enhancement Proposals; PEP 3118 <2>: API changes.   (line   29)
* Python Enhancement Proposals; PEP 3118 <3>: Build and C API Changes<4>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 3118 <4>: Build and C API Changes<7>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 3118 <5>: PEP 3118 Revised Buffer Protocol.
                                                             (line   46)
* Python Enhancement Proposals; PEP 3118 <6>: Library<149>.  (line   99)
* Python Enhancement Proposals; PEP 3118 <7>: Library<154>.  (line   61)
* Python Enhancement Proposals; PEP 3118 <8>: Library<183>.  (line  958)
* Python Enhancement Proposals; PEP 3118 <9>: Memory Views.  (line  113)
* Python Enhancement Proposals; PEP 3119: PEP 3119 Abstract Base Classes.
                                                             (line  138)
* Python Enhancement Proposals; PEP 3119 <1>: Customizing instance and subclass checks.
                                                             (line   35)
* Python Enhancement Proposals; PEP 3119 <2>: Examples and Recipes.
                                                             (line   73)
* Python Enhancement Proposals; PEP 3119 <3>: abc — Abstract Base Classes.
                                                             (line   11)
* Python Enhancement Proposals; PEP 3119 <4>: Object Protocol.
                                                             (line  395)
* Python Enhancement Proposals; PEP 3119 <5>: Object Protocol.
                                                             (line  415)
* Python Enhancement Proposals; PEP 3120: Text Vs Data Instead Of Unicode Vs 8-bit.
                                                             (line  105)
* Python Enhancement Proposals; PEP 3120 <1>: Lexical analysis.
                                                             (line   13)
* Python Enhancement Proposals; PEP 3120 <2>: Introduction<12>.
                                                             (line   91)
* Python Enhancement Proposals; PEP 3121: Build and C API Changes<7>.
                                                             (line   14)
* Python Enhancement Proposals; PEP 3121 <1>: Library<123>.  (line    6)
* Python Enhancement Proposals; PEP 3121 <2>: Initializing C modules.
                                                             (line   56)
* Python Enhancement Proposals; PEP 3123: Build and C API Changes<7>.
                                                             (line   16)
* Python Enhancement Proposals; PEP 3127: PEP 3127 Integer Literal Support and Syntax.
                                                             (line   47)
* Python Enhancement Proposals; PEP 3129: PEP 3129 Class Decorators.
                                                             (line   24)
* Python Enhancement Proposals; PEP 3129 <1>: Function definitions.
                                                             (line  169)
* Python Enhancement Proposals; PEP 3129 <2>: Class definitions.
                                                             (line   89)
* Python Enhancement Proposals; PEP 3131: Text Vs Data Instead Of Unicode Vs 8-bit.
                                                             (line  107)
* Python Enhancement Proposals; PEP 3131 <1>: Library<138>.  (line  599)
* Python Enhancement Proposals; PEP 3131 <2>: Identifiers and keywords.
                                                             (line   10)
* Python Enhancement Proposals; PEP 3131 <3>: Identifiers and keywords.
                                                             (line   17)
* Python Enhancement Proposals; PEP 3132: New Syntax.        (line   28)
* Python Enhancement Proposals; PEP 3132 <1>: Assignment statements.
                                                             (line  158)
* Python Enhancement Proposals; PEP 3134: Changed Syntax.    (line    6)
* Python Enhancement Proposals; PEP 3134 <1>: Changes To Exceptions.
                                                             (line   40)
* Python Enhancement Proposals; PEP 3134 <2>: Changes To Exceptions.
                                                             (line   61)
* Python Enhancement Proposals; PEP 3134 <3>: Library<68>.   (line   48)
* Python Enhancement Proposals; PEP 3134 <4>: Base classes.  (line   29)
* Python Enhancement Proposals; PEP 3135: Builtins.          (line    6)
* Python Enhancement Proposals; PEP 3135 <1>: Creating the class object.
                                                             (line   53)
* Python Enhancement Proposals; PEP 3137: PEP 3137 The memoryview Object.
                                                             (line   49)
* Python Enhancement Proposals; PEP 3138: Text Vs Data Instead Of Unicode Vs 8-bit.
                                                             (line  101)
* Python Enhancement Proposals; PEP 314: PEP 314 Metadata for Python Software Packages v1 1.
                                                             (line   42)
* Python Enhancement Proposals; PEP 3141: PEP 3141 A Type Hierarchy for Numbers.
                                                             (line   43)
* Python Enhancement Proposals; PEP 3141 <1>: numbers — Numeric abstract base classes.
                                                             (line   10)
* Python Enhancement Proposals; PEP 3141 <2>: abc — Abstract Base Classes.
                                                             (line   12)
* Python Enhancement Proposals; PEP 3144: ipaddress<6>.      (line   10)
* Python Enhancement Proposals; PEP 3147: PEP 421 Adding sys implementation.
                                                             (line   21)
* Python Enhancement Proposals; PEP 3147 <1>: PEP 3147 PYC Repository Directories.
                                                             (line   69)
* Python Enhancement Proposals; PEP 3147 <2>: “Compiled” Python files.
                                                             (line   47)
* Python Enhancement Proposals; PEP 3147 <3>: Import-related attributes on module objects.
                                                             (line  156)
* Python Enhancement Proposals; PEP 3147 <4>: test support import_helper — Utilities for import tests.
                                                             (line   82)
* Python Enhancement Proposals; PEP 3147 <5>: runpy — Locating and executing Python modules.
                                                             (line   85)
* Python Enhancement Proposals; PEP 3147 <6>: Introduction<12>.
                                                             (line   95)
* Python Enhancement Proposals; PEP 3147 <7>: importlib util – Utility code for importers.
                                                             (line   24)
* Python Enhancement Proposals; PEP 3147 <8>: importlib util – Utility code for importers.
                                                             (line   60)
* Python Enhancement Proposals; PEP 3147 <9>: importlib util – Utility code for importers.
                                                             (line   64)
* Python Enhancement Proposals; PEP 3147 <10>: py_compile — Compile Python source files.
                                                             (line   30)
* Python Enhancement Proposals; PEP 3147 <11>: py_compile — Compile Python source files.
                                                             (line   70)
* Python Enhancement Proposals; PEP 3147 <12>: Command-line use.
                                                             (line   70)
* Python Enhancement Proposals; PEP 3147 <13>: Public functions.
                                                             (line   40)
* Python Enhancement Proposals; PEP 3147 <14>: Public functions.
                                                             (line  122)
* Python Enhancement Proposals; PEP 3147 <15>: Importing Modules<2>.
                                                             (line  217)
* Python Enhancement Proposals; PEP 3147 <16>: How do I create a pyc file?.
                                                             (line   12)
* Python Enhancement Proposals; PEP 3148: PEP 3148 The concurrent futures module.
                                                             (line   51)
* Python Enhancement Proposals; PEP 3148 <1>: Module Functions.
                                                             (line   61)
* Python Enhancement Proposals; PEP 3149: PEP 3149 ABI Version Tagged so Files.
                                                             (line   33)
* Python Enhancement Proposals; PEP 3149 <1>: Core and Builtins<178>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 3149 <2>: sys — System-specific parameters and functions.
                                                             (line   16)
* Python Enhancement Proposals; PEP 3151: PEP 3151 Reworking the OS and IO exception hierarchy.
                                                             (line   84)
* Python Enhancement Proposals; PEP 3151 <1>: OS exceptions. (line  123)
* Python Enhancement Proposals; PEP 3151 <2>: Exceptions<15>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 3151 <3>: select — Waiting for I/O completion.
                                                             (line   33)
* Python Enhancement Proposals; PEP 3151 <4>: resource — Resource usage information.
                                                             (line   23)
* Python Enhancement Proposals; PEP 3151 <5>: Exception types.
                                                             (line  252)
* Python Enhancement Proposals; PEP 3154: Summary – Release Highlights<3>.
                                                             (line   57)
* Python Enhancement Proposals; PEP 3154 <1>: pickle<4>.     (line   16)
* Python Enhancement Proposals; PEP 3154 <2>: Library<138>.  (line 1279)
* Python Enhancement Proposals; PEP 3154 <3>: Data stream format.
                                                             (line   42)
* Python Enhancement Proposals; PEP 3155: PEP 3155 Qualified name for classes and functions.
                                                             (line   63)
* Python Enhancement Proposals; PEP 3155 <1>: Glossary.      (line 1425)
* Python Enhancement Proposals; PEP 3156: Summary – Release Highlights<3>.
                                                             (line   31)
* Python Enhancement Proposals; PEP 3156 <1>: Summary – Release Highlights<3>.
                                                             (line   44)
* Python Enhancement Proposals; PEP 3156 <2>: asyncio<11>.   (line    6)
* Python Enhancement Proposals; PEP 3156 <3>: asyncio<11>.   (line   17)
* Python Enhancement Proposals; PEP 3156 <4>: selectors<2>.  (line    6)
* Python Enhancement Proposals; PEP 318: PEP 318 Decorators for Functions and Methods.
                                                             (line  101)
* Python Enhancement Proposals; PEP 318 <1>: PEP 318 Decorators for Functions and Methods.
                                                             (line  125)
* Python Enhancement Proposals; PEP 318 <2>: Other Language Changes<17>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 318 <3>: Function definitions.
                                                             (line  166)
* Python Enhancement Proposals; PEP 318 <4>: Class definitions.
                                                             (line   92)
* Python Enhancement Proposals; PEP 322: PEP 322 Reverse Iteration.
                                                             (line   35)
* Python Enhancement Proposals; PEP 322 <1>: Other Language Changes<17>.
                                                             (line   13)
* Python Enhancement Proposals; PEP 324: PEP 324 New subprocess Module.
                                                             (line   86)
* Python Enhancement Proposals; PEP 324 <1>: subprocess — Subprocess management.
                                                             (line   23)
* Python Enhancement Proposals; PEP 325: PEP 342 New Generator Features.
                                                             (line  147)
* Python Enhancement Proposals; PEP 327: The Context type.   (line   56)
* Python Enhancement Proposals; PEP 328: Porting Python code.
                                                             (line   36)
* Python Enhancement Proposals; PEP 328 <1>: Removed Syntax. (line   28)
* Python Enhancement Proposals; PEP 328 <2>: PEP 328 Absolute and Relative Imports.
                                                             (line    6)
* Python Enhancement Proposals; PEP 328 <3>: PEP 328 Absolute and Relative Imports.
                                                             (line   82)
* Python Enhancement Proposals; PEP 328 <4>: PEP 328 Multi-line Imports.
                                                             (line   35)
* Python Enhancement Proposals; PEP 328 <5>: Other Language Changes<17>.
                                                             (line   21)
* Python Enhancement Proposals; PEP 328 <6>: References.     (line   20)
* Python Enhancement Proposals; PEP 328 <7>: Built-in Functions.
                                                             (line 2199)
* Python Enhancement Proposals; PEP 328 <8>: Module Contents<4>.
                                                             (line   26)
* Python Enhancement Proposals; PEP 328 <9>: Introduction<12>.
                                                             (line   63)
* Python Enhancement Proposals; PEP 331: PEP 331 Locale-Independent Float/String Conversions.
                                                             (line   38)
* Python Enhancement Proposals; PEP 333: The wsgiref package.
                                                             (line    8)
* Python Enhancement Proposals; PEP 333 <1>: The wsgiref package.
                                                             (line   31)
* Python Enhancement Proposals; PEP 3333: New Modules<3>.    (line    9)
* Python Enhancement Proposals; PEP 3333 <1>: PEP 3333 Python Web Server Gateway Interface v1 0 1.
                                                             (line   50)
* Python Enhancement Proposals; PEP 3333 <2>: wsgiref — WSGI Utilities and Reference Implementation.
                                                             (line   30)
* Python Enhancement Proposals; PEP 3333 <3>: wsgiref util – WSGI environment utilities.
                                                             (line    8)
* Python Enhancement Proposals; PEP 3333 <4>: wsgiref util – WSGI environment utilities.
                                                             (line   10)
* Python Enhancement Proposals; PEP 3333 <5>: wsgiref util – WSGI environment utilities.
                                                             (line   30)
* Python Enhancement Proposals; PEP 3333 <6>: wsgiref util – WSGI environment utilities.
                                                             (line   76)
* Python Enhancement Proposals; PEP 3333 <7>: wsgiref headers – WSGI response header tools.
                                                             (line   12)
* Python Enhancement Proposals; PEP 3333 <8>: wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   21)
* Python Enhancement Proposals; PEP 3333 <9>: wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   98)
* Python Enhancement Proposals; PEP 3333 <10>: wsgiref validate — WSGI conformance checker.
                                                             (line   13)
* Python Enhancement Proposals; PEP 3333 <11>: wsgiref validate — WSGI conformance checker.
                                                             (line   40)
* Python Enhancement Proposals; PEP 3333 <12>: wsgiref handlers – server/gateway base classes.
                                                             (line  235)
* Python Enhancement Proposals; PEP 3333 <13>: wsgiref handlers – server/gateway base classes.
                                                             (line  253)
* Python Enhancement Proposals; PEP 3333 <14>: wsgiref handlers – server/gateway base classes.
                                                             (line  260)
* Python Enhancement Proposals; PEP 3333 <15>: wsgiref handlers – server/gateway base classes.
                                                             (line  269)
* Python Enhancement Proposals; PEP 3333 <16>: wsgiref handlers – server/gateway base classes.
                                                             (line  312)
* Python Enhancement Proposals; PEP 3333 <17>: wsgiref types – WSGI types for static type checking.
                                                             (line    7)
* Python Enhancement Proposals; PEP 3333 <18>: wsgiref types – WSGI types for static type checking.
                                                             (line   14)
* Python Enhancement Proposals; PEP 3333#input-and-error-streams: wsgiref types – WSGI types for static type checking.
                                                             (line   26)
* Python Enhancement Proposals; PEP 3333#input-and-error-streams <1>: wsgiref types – WSGI types for static type checking.
                                                             (line   30)
* Python Enhancement Proposals; PEP 3333#optional-platform-specific-file-handling: wsgiref types – WSGI types for static type checking.
                                                             (line   34)
* Python Enhancement Proposals; PEP 3333#the-start-response-callable: wsgiref types – WSGI types for static type checking.
                                                             (line   13)
* Python Enhancement Proposals; PEP 338: PEP 338 Executing Modules as Scripts.
                                                             (line   21)
* Python Enhancement Proposals; PEP 338 <1>: Interface options.
                                                             (line  100)
* Python Enhancement Proposals; PEP 338 <2>: References.     (line   24)
* Python Enhancement Proposals; PEP 338 <3>: runpy — Locating and executing Python modules.
                                                             (line  176)
* Python Enhancement Proposals; PEP 339: Build and C API Changes<10>.
                                                             (line   46)
* Python Enhancement Proposals; PEP 341: PEP 341 Unified try/except/finally.
                                                             (line   44)
* Python Enhancement Proposals; PEP 342: PEP 342 New Generator Features.
                                                             (line   42)
* Python Enhancement Proposals; PEP 342 <1>: PEP 342 New Generator Features.
                                                             (line  140)
* Python Enhancement Proposals; PEP 342 <2>: Porting to Python 2 5.
                                                             (line   15)
* Python Enhancement Proposals; PEP 342 <3>: Yield expressions.
                                                             (line   95)
* Python Enhancement Proposals; PEP 342 <4>: Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   58)
* Python Enhancement Proposals; PEP 342 <5>: Passing values into a generator.
                                                             (line   25)
* Python Enhancement Proposals; PEP 342 <6>: Python documentation.
                                                             (line   14)
* Python Enhancement Proposals; PEP 343: The contextlib module.
                                                             (line   64)
* Python Enhancement Proposals; PEP 343 <1>: PEP 342 New Generator Features.
                                                             (line  129)
* Python Enhancement Proposals; PEP 343 <2>: The contextlib module<2>.
                                                             (line   64)
* Python Enhancement Proposals; PEP 343 <3>: With Statement Context Managers.
                                                             (line   46)
* Python Enhancement Proposals; PEP 343 <4>: The with statement.
                                                             (line  114)
* Python Enhancement Proposals; PEP 343 <5>: Using a context manager as a function decorator.
                                                             (line   51)
* Python Enhancement Proposals; PEP 343 <6>: Module Contents<4>.
                                                             (line   31)
* Python Enhancement Proposals; PEP 343 <7>: Glossary.       (line  340)
* Python Enhancement Proposals; PEP 343 <8>: Glossary.       (line  346)
* Python Enhancement Proposals; PEP 347: Build and C API Changes<10>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 352: Changes To Exceptions.
                                                             (line    9)
* Python Enhancement Proposals; PEP 352 <1>: Deprecations and Removals.
                                                             (line    9)
* Python Enhancement Proposals; PEP 352 <2>: PEP 352 Exceptions as New-Style Classes.
                                                             (line   57)
* Python Enhancement Proposals; PEP 353: Porting to Python 3 10<2>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 353 <1>: PEP 353 Using ssize_t as the index type.
                                                             (line   48)
* Python Enhancement Proposals; PEP 353 <2>: PEP 353 Using ssize_t as the index type.
                                                             (line   54)
* Python Enhancement Proposals; PEP 353 <3>: Build and C API Changes<10>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 353 <4>: C API<44>.      (line   80)
* Python Enhancement Proposals; PEP 353 <5>: Types.          (line   17)
* Python Enhancement Proposals; PEP 356: What’s New in Python 2 5.
                                                             (line   10)
* Python Enhancement Proposals; PEP 357: PEP 357 The ‘__index__’ method.
                                                             (line   39)
* Python Enhancement Proposals; PEP 361: What’s New in Python 2 6.
                                                             (line   10)
* Python Enhancement Proposals; PEP 362: PEP 362 Function Signature Object.
                                                             (line   19)
* Python Enhancement Proposals; PEP 362 <1>: Introspecting callables with the Signature object.
                                                             (line  397)
* Python Enhancement Proposals; PEP 362 <2>: Glossary.       (line   86)
* Python Enhancement Proposals; PEP 362 <3>: Glossary.       (line 1299)
* Python Enhancement Proposals; PEP 366: Visible Changes.    (line   24)
* Python Enhancement Proposals; PEP 366 <1>: Import-related attributes on module objects.
                                                             (line   63)
* Python Enhancement Proposals; PEP 366 <2>: References.     (line   17)
* Python Enhancement Proposals; PEP 366 <3>: References.     (line   21)
* Python Enhancement Proposals; PEP 366 <4>: runpy — Locating and executing Python modules.
                                                             (line  180)
* Python Enhancement Proposals; PEP 366 <5>: Introduction<12>.
                                                             (line   67)
* Python Enhancement Proposals; PEP 370: PEP 370 Per-user site-packages Directory.
                                                             (line   36)
* Python Enhancement Proposals; PEP 370 <1>: Library<63>.    (line  604)
* Python Enhancement Proposals; PEP 370 <2>: Miscellaneous options.
                                                             (line  164)
* Python Enhancement Proposals; PEP 370 <3>: Environment variables.
                                                             (line  202)
* Python Enhancement Proposals; PEP 370 <4>: Environment variables.
                                                             (line  214)
* Python Enhancement Proposals; PEP 370 <5>: Command-line interface<9>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 371: PEP 371 The multiprocessing Package.
                                                             (line  146)
* Python Enhancement Proposals; PEP 372: PEP 372 Ordered Dictionaries.
                                                             (line   31)
* Python Enhancement Proposals; PEP 372 <1>: PEP 372 Adding an Ordered Dictionary to collections.
                                                             (line   97)
* Python Enhancement Proposals; PEP 373: The Future for Python 2 x.
                                                             (line   23)
* Python Enhancement Proposals; PEP 373 <1>: How stable is Python?.
                                                             (line   20)
* Python Enhancement Proposals; PEP 378: PEP 378 Format Specifier for Thousands Separator.
                                                             (line   32)
* Python Enhancement Proposals; PEP 378 <1>: PEP 378 Format Specifier for Thousands Separator<2>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 378 <2>: Format specification mini-language.
                                                             (line  144)
* Python Enhancement Proposals; PEP 380: PEP 380 Syntax for Delegating to a Subgenerator.
                                                             (line   66)
* Python Enhancement Proposals; PEP 380 <1>: Yield expressions.
                                                             (line  100)
* Python Enhancement Proposals; PEP 380#use-of-stopiteration-to-return-values: The STOP_ITERATION event.
                                                             (line    6)
* Python Enhancement Proposals; PEP 383: Documentation<27>.  (line   29)
* Python Enhancement Proposals; PEP 383 <1>: Error Handlers. (line   50)
* Python Enhancement Proposals; PEP 383 <2>: Socket families.
                                                             (line   15)
* Python Enhancement Proposals; PEP 383 <3>: Locale Encoding.
                                                             (line   15)
* Python Enhancement Proposals; PEP 383 <4>: Locale Encoding.
                                                             (line   52)
* Python Enhancement Proposals; PEP 383 <5>: File System Encoding.
                                                             (line    7)
* Python Enhancement Proposals; PEP 384: Removed<6>.         (line   53)
* Python Enhancement Proposals; PEP 384 <1>: PEP 384 Defining a Stable ABI.
                                                             (line   24)
* Python Enhancement Proposals; PEP 384 <2>: C API<38>.      (line  100)
* Python Enhancement Proposals; PEP 385: Code Repository.    (line   13)
* Python Enhancement Proposals; PEP 387: Warnings.           (line   26)
* Python Enhancement Proposals; PEP 387 <1>: Warnings.       (line   41)
* Python Enhancement Proposals; PEP 387 <2>: C API Stability.
                                                             (line    7)
* Python Enhancement Proposals; PEP 387 <3>: Stable ABI.     (line   13)
* Python Enhancement Proposals; PEP 387 <4>: How does the Python version numbering scheme work?.
                                                             (line   46)
* Python Enhancement Proposals; PEP 389: PEP 389 Argparse Command Line Parsing Module.
                                                             (line   92)
* Python Enhancement Proposals; PEP 389 <1>: PEP 389 The argparse Module for Parsing Command Lines.
                                                             (line   99)
* Python Enhancement Proposals; PEP 391: PEP 391 Dictionary Based Configuration for Logging.
                                                             (line   52)
* Python Enhancement Proposals; PEP 391 <1>: PEP 391 Dictionary-Based Configuration For Logging.
                                                             (line   95)
* Python Enhancement Proposals; PEP 392: What’s New In Python 3 2.
                                                             (line   17)
* Python Enhancement Proposals; PEP 393: Removed<6>.         (line   26)
* Python Enhancement Proposals; PEP 393 <1>: Porting to Python 3 9<2>.
                                                             (line   45)
* Python Enhancement Proposals; PEP 393 <2>: Removed<8>.     (line  101)
* Python Enhancement Proposals; PEP 393 <3>: PEP 393 Flexible String Representation.
                                                             (line   16)
* Python Enhancement Proposals; PEP 393 <4>: Functionality.  (line    6)
* Python Enhancement Proposals; PEP 393 <5>: Performance and resource usage.
                                                             (line   29)
* Python Enhancement Proposals; PEP 393 <6>: Optimizations<10>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 393 <7>: Build and C API Changes<4>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 393 <8>: Deprecated Python modules functions and methods<4>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 393 <9>: Deprecated functions and types of the C API<3>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 393 <10>: Porting C code.
                                                             (line   17)
* Python Enhancement Proposals; PEP 393 <11>: C API<36>.     (line  143)
* Python Enhancement Proposals; PEP 393 <12>: Encodings and Unicode.
                                                             (line    7)
* Python Enhancement Proposals; PEP 393 <13>: sys — System-specific parameters and functions.
                                                             (line 1264)
* Python Enhancement Proposals; PEP 393 <14>: Unicode Objects.
                                                             (line    6)
* Python Enhancement Proposals; PEP 397: PEP 486 Make the Python Launcher aware of virtual environments.
                                                             (line    6)
* Python Enhancement Proposals; PEP 397 <1>: PEP 397 Python Launcher for Windows.
                                                             (line   31)
* Python Enhancement Proposals; PEP 397 <2>: Python Launcher for Windows.
                                                             (line   18)
* Python Enhancement Proposals; PEP 398: What’s New In Python 3 3.
                                                             (line   13)
* Python Enhancement Proposals; PEP 4:   Library Changes.    (line   13)
* Python Enhancement Proposals; PEP 405: PEP 405 Virtual Environments.
                                                             (line   22)
* Python Enhancement Proposals; PEP 405 <1>: venv — Creation of virtual environments.
                                                             (line   45)
* Python Enhancement Proposals; PEP 409: PEP 409 Suppressing exception context.
                                                             (line   63)
* Python Enhancement Proposals; PEP 411: sys — System-specific parameters and functions.
                                                             (line 1015)
* Python Enhancement Proposals; PEP 411 <1>: sys — System-specific parameters and functions.
                                                             (line 1025)
* Python Enhancement Proposals; PEP 411 <2>: sys — System-specific parameters and functions.
                                                             (line 1726)
* Python Enhancement Proposals; PEP 411 <3>: sys — System-specific parameters and functions.
                                                             (line 1746)
* Python Enhancement Proposals; PEP 411 <4>: Glossary.       (line 1392)
* Python Enhancement Proposals; PEP 412: PEP 412 Key-Sharing Dictionary.
                                                             (line   15)
* Python Enhancement Proposals; PEP 412 <1>: functools — Higher-order functions and operations on callable objects.
                                                             (line   90)
* Python Enhancement Proposals; PEP 414: PEP 414 Explicit Unicode literals.
                                                             (line   17)
* Python Enhancement Proposals; PEP 414 <1>: String and Bytes literals.
                                                             (line   61)
* Python Enhancement Proposals; PEP 418: time<8>.            (line    6)
* Python Enhancement Proposals; PEP 420: PEP 420 Implicit Namespace Packages.
                                                             (line    9)
* Python Enhancement Proposals; PEP 420 <1>: PEP 420 Implicit Namespace Packages.
                                                             (line   14)
* Python Enhancement Proposals; PEP 420 <2>: Core and Builtins<163>.
                                                             (line   56)
* Python Enhancement Proposals; PEP 420 <3>: Core and Builtins<168>.
                                                             (line  114)
* Python Enhancement Proposals; PEP 420 <4>: The import system.
                                                             (line   44)
* Python Enhancement Proposals; PEP 420 <5>: Namespace packages.
                                                             (line   27)
* Python Enhancement Proposals; PEP 420 <6>: __path__ attributes on modules.
                                                             (line   23)
* Python Enhancement Proposals; PEP 420 <7>: __path__ attributes on modules.
                                                             (line   23)
* Python Enhancement Proposals; PEP 420 <8>: References.     (line   11)
* Python Enhancement Proposals; PEP 420 <9>: References.     (line   13)
* Python Enhancement Proposals; PEP 420 <10>: References.    (line   13)
* Python Enhancement Proposals; PEP 420 <11>: Introduction<12>.
                                                             (line   71)
* Python Enhancement Proposals; PEP 420 <12>: Glossary.      (line 1171)
* Python Enhancement Proposals; PEP 420 <13>: Glossary.      (line 1367)
* Python Enhancement Proposals; PEP 421: SimpleNamespace.    (line   16)
* Python Enhancement Proposals; PEP 421 <1>: sys — System-specific parameters and functions.
                                                             (line 1135)
* Python Enhancement Proposals; PEP 421 <2>: sys — System-specific parameters and functions.
                                                             (line 1140)
* Python Enhancement Proposals; PEP 424: Other Language Changes<10>.
                                                             (line   57)
* Python Enhancement Proposals; PEP 424 <1>: operator<3>.    (line    8)
* Python Enhancement Proposals; PEP 428: Summary – Release Highlights<3>.
                                                             (line   39)
* Python Enhancement Proposals; PEP 428 <1>: pathlib<11>.    (line   17)
* Python Enhancement Proposals; PEP 428 <2>: pathlib — Object-oriented filesystem paths.
                                                             (line   41)
* Python Enhancement Proposals; PEP 429: What’s New In Python 3 4.
                                                             (line   16)
* Python Enhancement Proposals; PEP 432: Other CPython implementation changes.
                                                             (line    7)
* Python Enhancement Proposals; PEP 432 <1>: Core and Builtins<146>.
                                                             (line  312)
* Python Enhancement Proposals; PEP 432 <2>: Multi-Phase Initialization Private Provisional API.
                                                             (line    7)
* Python Enhancement Proposals; PEP 432 <3>: Multi-Phase Initialization Private Provisional API.
                                                             (line   57)
* Python Enhancement Proposals; PEP 434: PEP 434 IDLE Enhancement Exception for All Branches.
                                                             (line    6)
* Python Enhancement Proposals; PEP 434 <1>: idlelib — implementation of IDLE application.
                                                             (line   17)
* Python Enhancement Proposals; PEP 435: Summary – Release Highlights<3>.
                                                             (line   36)
* Python Enhancement Proposals; PEP 435 <1>: enum<9>.        (line    6)
* Python Enhancement Proposals; PEP 435 <2>: enum<9>.        (line   15)
* Python Enhancement Proposals; PEP 436: Summary – Release Highlights<3>.
                                                             (line  120)
* Python Enhancement Proposals; PEP 436 <1>: PEP 436 Argument Clinic.
                                                             (line    6)
* Python Enhancement Proposals; PEP 436 <2>: PEP 436 Argument Clinic.
                                                             (line   28)
* Python Enhancement Proposals; PEP 441: zipapp<2>.          (line    6)
* Python Enhancement Proposals; PEP 441 <1>: zipapp<2>.      (line   24)
* Python Enhancement Proposals; PEP 442: Removed<7>.         (line   68)
* Python Enhancement Proposals; PEP 442 <1>: Summary – Release Highlights<3>.
                                                             (line  113)
* Python Enhancement Proposals; PEP 442 <2>: Summary – Release Highlights<3>.
                                                             (line  115)
* Python Enhancement Proposals; PEP 442 <3>: PEP 442 Safe Object Finalization.
                                                             (line    6)
* Python Enhancement Proposals; PEP 442 <4>: PEP 442 Safe Object Finalization.
                                                             (line   21)
* Python Enhancement Proposals; PEP 442 <5>: C API<51>.      (line   55)
* Python Enhancement Proposals; PEP 442 <6>: gc — Garbage Collector interface.
                                                             (line  253)
* Python Enhancement Proposals; PEP 442 <7>: Thin Ice.       (line   38)
* Python Enhancement Proposals; PEP 442 <8>: Finalization and De-allocation.
                                                             (line   89)
* Python Enhancement Proposals; PEP 442 <9>: PyTypeObject Slots.
                                                             (line 1793)
* Python Enhancement Proposals; PEP 443: Summary – Release Highlights<3>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 443 <1>: functools<5>.   (line   22)
* Python Enhancement Proposals; PEP 443 <2>: Glossary.       (line  711)
* Python Enhancement Proposals; PEP 445: Summary – Release Highlights<3>.
                                                             (line  118)
* Python Enhancement Proposals; PEP 445 <1>: PEP 445 Customization of CPython Memory Allocators.
                                                             (line    6)
* Python Enhancement Proposals; PEP 445 <2>: PEP 445 Customization of CPython Memory Allocators.
                                                             (line   12)
* Python Enhancement Proposals; PEP 445 <3>: Other Improvements<2>.
                                                             (line   63)
* Python Enhancement Proposals; PEP 446: Summary – Release Highlights<3>.
                                                             (line   14)
* Python Enhancement Proposals; PEP 446 <1>: Summary – Release Highlights<3>.
                                                             (line   78)
* Python Enhancement Proposals; PEP 446 <2>: PEP 446 Newly Created File Descriptors Are Non-Inheritable.
                                                             (line    6)
* Python Enhancement Proposals; PEP 446 <3>: PEP 446 Newly Created File Descriptors Are Non-Inheritable.
                                                             (line   26)
* Python Enhancement Proposals; PEP 446 <4>: Core and Builtins<33>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 448: PEP 448 - Additional Unpacking Generalizations.
                                                             (line    6)
* Python Enhancement Proposals; PEP 448 <1>: PEP 448 - Additional Unpacking Generalizations.
                                                             (line   39)
* Python Enhancement Proposals; PEP 448 <2>: Documentation<74>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 448 <3>: Documentation<78>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 448 <4>: Core and Builtins<171>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 448 <5>: Core and Builtins<174>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 448 <6>: Dictionary displays.
                                                             (line   29)
* Python Enhancement Proposals; PEP 448 <7>: Calls.          (line  122)
* Python Enhancement Proposals; PEP 448 <8>: Expression lists.
                                                             (line   24)
* Python Enhancement Proposals; PEP 450: Summary – Release Highlights<3>.
                                                             (line   47)
* Python Enhancement Proposals; PEP 450 <1>: statistics<6>.  (line    6)
* Python Enhancement Proposals; PEP 450 <2>: statistics<6>.  (line   14)
* Python Enhancement Proposals; PEP 451: zipimport<2>.       (line    8)
* Python Enhancement Proposals; PEP 451 <1>: zipimport<3>.   (line    6)
* Python Enhancement Proposals; PEP 451 <2>: PEP 489 Multi-phase extension module initialization.
                                                             (line    7)
* Python Enhancement Proposals; PEP 451 <3>: Summary – Release Highlights<3>.
                                                             (line   22)
* Python Enhancement Proposals; PEP 451 <4>: PEP 451 A ModuleSpec Type for the Import System.
                                                             (line    6)
* Python Enhancement Proposals; PEP 451 <5>: Library<63>.    (line  457)
* Python Enhancement Proposals; PEP 451 <6>: Core and Builtins<163>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 451 <7>: References.     (line   26)
* Python Enhancement Proposals; PEP 451 <8>: sys — System-specific parameters and functions.
                                                             (line 1296)
* Python Enhancement Proposals; PEP 451 <9>: pkgutil — Package extension utility.
                                                             (line   67)
* Python Enhancement Proposals; PEP 451 <10>: pkgutil — Package extension utility.
                                                             (line  101)
* Python Enhancement Proposals; PEP 451 <11>: runpy — Locating and executing Python modules.
                                                             (line   89)
* Python Enhancement Proposals; PEP 451 <12>: runpy — Locating and executing Python modules.
                                                             (line  166)
* Python Enhancement Proposals; PEP 451 <13>: runpy — Locating and executing Python modules.
                                                             (line  184)
* Python Enhancement Proposals; PEP 451 <14>: Introduction<12>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 451 <15>: Multi-phase initialization.
                                                             (line   88)
* Python Enhancement Proposals; PEP 453: Summary – Release Highlights<3>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 453 <1>: Summary – Release Highlights<3>.
                                                             (line   34)
* Python Enhancement Proposals; PEP 453 <2>: Bootstrapping pip By Default.
                                                             (line    6)
* Python Enhancement Proposals; PEP 453 <3>: Documentation Changes.
                                                             (line   21)
* Python Enhancement Proposals; PEP 453 <4>: ensurepip<2>.   (line    7)
* Python Enhancement Proposals; PEP 453 <5>: venv<7>.        (line   13)
* Python Enhancement Proposals; PEP 453 <6>: Other Improvements<2>.
                                                             (line   73)
* Python Enhancement Proposals; PEP 453 <7>: PEP 477 Backport ensurepip PEP 453 to Python 2 7.
                                                             (line    6)
* Python Enhancement Proposals; PEP 453 <8>: Bootstrapping pip By Default<2>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 453 <9>: Documentation Changes<2>.
                                                             (line   21)
* Python Enhancement Proposals; PEP 453 <10>: ensurepip — Bootstrapping the pip installer.
                                                             (line   35)
* Python Enhancement Proposals; PEP 454: Summary – Release Highlights<3>.
                                                             (line   50)
* Python Enhancement Proposals; PEP 454 <1>: tracemalloc<4>. (line    6)
* Python Enhancement Proposals; PEP 454 <2>: tracemalloc<4>. (line   22)
* Python Enhancement Proposals; PEP 456: Summary – Release Highlights<3>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 456 <1>: PEP 456 Secure and Interchangeable Hash Algorithm.
                                                             (line    6)
* Python Enhancement Proposals; PEP 456 <2>: PyHash API.     (line  140)
* Python Enhancement Proposals; PEP 461: PEP 461 - percent formatting support for bytes and bytearray.
                                                             (line    6)
* Python Enhancement Proposals; PEP 461 <1>: PEP 461 - percent formatting support for bytes and bytearray.
                                                             (line   41)
* Python Enhancement Proposals; PEP 461 <2>: printf-style Bytes Formatting.
                                                             (line  198)
* Python Enhancement Proposals; PEP 465: PEP 465 - A dedicated infix operator for matrix multiplication.
                                                             (line    6)
* Python Enhancement Proposals; PEP 465 <1>: PEP 465 - A dedicated infix operator for matrix multiplication.
                                                             (line   45)
* Python Enhancement Proposals; PEP 465 <2>: Build and C API Changes<3>.
                                                             (line   43)
* Python Enhancement Proposals; PEP 465 <3>: Tools/Demos<54>.
                                                             (line   39)
* Python Enhancement Proposals; PEP 466: PEP 466 Network Security Enhancements for Python 2 7.
                                                             (line    6)
* Python Enhancement Proposals; PEP 466 <1>: PEP 466 Network Security Enhancements for Python 2 7.
                                                             (line   11)
* Python Enhancement Proposals; PEP 466 <2>: PEP 466 Network Security Enhancements for Python 2 7.
                                                             (line   21)
* Python Enhancement Proposals; PEP 466 <3>: PEP 466 Network Security Enhancements for Python 2 7.
                                                             (line   32)
* Python Enhancement Proposals; PEP 468: PEP 468 Preserving Keyword Argument Order.
                                                             (line   12)
* Python Enhancement Proposals; PEP 468 <1>: Library<156>.   (line   87)
* Python Enhancement Proposals; PEP 468 <2>: OrderedDict objects.
                                                             (line  109)
* Python Enhancement Proposals; PEP 471: PEP 471 - os scandir function – a better and faster directory iterator.
                                                             (line    6)
* Python Enhancement Proposals; PEP 471 <1>: PEP 471 - os scandir function – a better and faster directory iterator.
                                                             (line   29)
* Python Enhancement Proposals; PEP 471 <2>: Library<182>.   (line    6)
* Python Enhancement Proposals; PEP 475: PEP 475 Retry system calls failing with EINTR.
                                                             (line   32)
* Python Enhancement Proposals; PEP 475 <1>: PEP 475 Retry system calls failing with EINTR.
                                                             (line   77)
* Python Enhancement Proposals; PEP 475 <2>: Changes in the Python API<9>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 475 <3>: Library<147>.   (line  228)
* Python Enhancement Proposals; PEP 475 <4>: Library<180>.   (line  143)
* Python Enhancement Proposals; PEP 475 <5>: Built-in Functions.
                                                             (line 1495)
* Python Enhancement Proposals; PEP 475 <6>: OS exceptions.  (line   80)
* Python Enhancement Proposals; PEP 475 <7>: File Descriptor Operations.
                                                             (line  409)
* Python Enhancement Proposals; PEP 475 <8>: File Descriptor Operations.
                                                             (line  749)
* Python Enhancement Proposals; PEP 475 <9>: File Descriptor Operations.
                                                             (line  936)
* Python Enhancement Proposals; PEP 475 <10>: Process Management.
                                                             (line  925)
* Python Enhancement Proposals; PEP 475 <11>: I/O Base Classes.
                                                             (line  279)
* Python Enhancement Proposals; PEP 475 <12>: I/O Base Classes.
                                                             (line  297)
* Python Enhancement Proposals; PEP 475 <13>: Functions<5>.  (line  311)
* Python Enhancement Proposals; PEP 475 <14>: Socket Objects.
                                                             (line   28)
* Python Enhancement Proposals; PEP 475 <15>: Socket Objects.
                                                             (line   81)
* Python Enhancement Proposals; PEP 475 <16>: Socket Objects.
                                                             (line  244)
* Python Enhancement Proposals; PEP 475 <17>: Socket Objects.
                                                             (line  259)
* Python Enhancement Proposals; PEP 475 <18>: Socket Objects.
                                                             (line  335)
* Python Enhancement Proposals; PEP 475 <19>: Socket Objects.
                                                             (line  407)
* Python Enhancement Proposals; PEP 475 <20>: Socket Objects.
                                                             (line  426)
* Python Enhancement Proposals; PEP 475 <21>: Socket Objects.
                                                             (line  445)
* Python Enhancement Proposals; PEP 475 <22>: Socket Objects.
                                                             (line  489)
* Python Enhancement Proposals; PEP 475 <23>: select — Waiting for I/O completion.
                                                             (line  159)
* Python Enhancement Proposals; PEP 475 <24>: /dev/poll Polling Objects.
                                                             (line   82)
* Python Enhancement Proposals; PEP 475 <25>: Edge and Level Trigger Polling epoll Objects.
                                                             (line  102)
* Python Enhancement Proposals; PEP 475 <26>: Polling Objects.
                                                             (line   94)
* Python Enhancement Proposals; PEP 475 <27>: Kqueue Objects.
                                                             (line   36)
* Python Enhancement Proposals; PEP 475 <28>: Classes<4>.    (line  133)
* Python Enhancement Proposals; PEP 475 <29>: Module contents<3>.
                                                             (line  621)
* Python Enhancement Proposals; PEP 475 <30>: Module contents<3>.
                                                             (line  640)
* Python Enhancement Proposals; PEP 476: PEP 476 Enabling certificate verification by default for stdlib http clients<2>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 477: PEP 477 Backport ensurepip PEP 453 to Python 2 7.
                                                             (line    6)
* Python Enhancement Proposals; PEP 478: What’s New In Python 3 5.
                                                             (line   17)
* Python Enhancement Proposals; PEP 479: Changes in Python Behavior.
                                                             (line   11)
* Python Enhancement Proposals; PEP 479 <1>: PEP 479 Change StopIteration handling inside generators.
                                                             (line   12)
* Python Enhancement Proposals; PEP 479 <2>: PEP 479 Change StopIteration handling inside generators.
                                                             (line   47)
* Python Enhancement Proposals; PEP 479 <3>: Library<138>.   (line 1267)
* Python Enhancement Proposals; PEP 479 <4>: Library<142>.   (line   52)
* Python Enhancement Proposals; PEP 479 <5>: Core and Builtins<142>.
                                                             (line   34)
* Python Enhancement Proposals; PEP 479 <6>: Library<150>.   (line   95)
* Python Enhancement Proposals; PEP 479 <7>: Library<163>.   (line   80)
* Python Enhancement Proposals; PEP 479 <8>: Library<169>.   (line  326)
* Python Enhancement Proposals; PEP 479 <9>: Concrete exceptions.
                                                             (line  291)
* Python Enhancement Proposals; PEP 479 <10>: Concrete exceptions.
                                                             (line  293)
* Python Enhancement Proposals; PEP 479 <11>: Module Contents<4>.
                                                             (line   43)
* Python Enhancement Proposals; PEP 483: PEP 484 - Type Hints.
                                                             (line   47)
* Python Enhancement Proposals; PEP 483 <1>: Glossary.       (line  719)
* Python Enhancement Proposals; PEP 484: PEP 695 Type Parameter Syntax.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <1>: New Features Related to Type Hints.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <2>: PEP 692 Using TypedDict for more precise **kwargs typing.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <3>: New Features Related to Type Hints<2>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <4>: PEP 646 Variadic generics.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <5>: New Features Related to Type Hints<3>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <6>: PEP 612 Parameter Specification Variables.
                                                             (line    7)
* Python Enhancement Proposals; PEP 484 <7>: PEP 613 TypeAlias.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <8>: ast<3>.         (line   17)
* Python Enhancement Proposals; PEP 484 <9>: ast<3>.         (line   20)
* Python Enhancement Proposals; PEP 484 <10>: PEP 560 Core Support for typing module and Generic Types.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <11>: PEP 526 Syntax for variable annotations.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <12>: PEP 484 - Type Hints.
                                                             (line   16)
* Python Enhancement Proposals; PEP 484 <13>: PEP 484 - Type Hints.
                                                             (line   41)
* Python Enhancement Proposals; PEP 484 <14>: Function Annotations.
                                                             (line    8)
* Python Enhancement Proposals; PEP 484 <15>: Emulating generic types.
                                                             (line   15)
* Python Enhancement Proposals; PEP 484 <16>: Annotated assignment statements.
                                                             (line   48)
* Python Enhancement Proposals; PEP 484 <17>: Function definitions.
                                                             (line  151)
* Python Enhancement Proposals; PEP 484 <18>: Special Attributes of GenericAlias objects.
                                                             (line   50)
* Python Enhancement Proposals; PEP 484 <19>: NewType.       (line   63)
* Python Enhancement Proposals; PEP 484 <20>: Nominal vs structural subtyping.
                                                             (line    6)
* Python Enhancement Proposals; PEP 484 <21>: Nominal vs structural subtyping.
                                                             (line   14)
* Python Enhancement Proposals; PEP 484 <22>: Building generic types and type aliases.
                                                             (line  113)
* Python Enhancement Proposals; PEP 484 <23>: Functions and decorators.
                                                             (line  280)
* Python Enhancement Proposals; PEP 484 <24>: Root nodes.    (line   60)
* Python Enhancement Proposals; PEP 484 <25>: ast Helpers.   (line   18)
* Python Enhancement Proposals; PEP 484 <26>: ast Helpers.   (line   29)
* Python Enhancement Proposals; PEP 484 <27>: Compiler Flags.
                                                             (line   30)
* Python Enhancement Proposals; PEP 484 <28>: Available start symbols.
                                                             (line   28)
* Python Enhancement Proposals; PEP 484 <29>: Available start symbols.
                                                             (line   37)
* Python Enhancement Proposals; PEP 484 <30>: Glossary.      (line   51)
* Python Enhancement Proposals; PEP 484 <31>: Glossary.      (line  646)
* Python Enhancement Proposals; PEP 484 <32>: Glossary.      (line  719)
* Python Enhancement Proposals; PEP 484 <33>: Glossary.      (line 1718)
* Python Enhancement Proposals; PEP 484 <34>: Glossary.      (line 1735)
* Python Enhancement Proposals; PEP 484 <35>: Glossary.      (line 1765)
* Python Enhancement Proposals; PEP 484#annotating-instance-and-class-methods: PEP 673 Self type.
                                                             (line    8)
* Python Enhancement Proposals; PEP 485: PEP 485 A function for testing approximate equality.
                                                             (line    6)
* Python Enhancement Proposals; PEP 485 <1>: PEP 485 A function for testing approximate equality.
                                                             (line   36)
* Python Enhancement Proposals; PEP 485 <2>: Library<178>.   (line   10)
* Python Enhancement Proposals; PEP 485 <3>: Floating point manipulation functions.
                                                             (line   58)
* Python Enhancement Proposals; PEP 485 <4>: Classification functions.
                                                             (line   56)
* Python Enhancement Proposals; PEP 486: PEP 486 Make the Python Launcher aware of virtual environments.
                                                             (line    6)
* Python Enhancement Proposals; PEP 486 <1>: PEP 486 Make the Python Launcher aware of virtual environments.
                                                             (line   14)
* Python Enhancement Proposals; PEP 486 <2>: Windows<80>.    (line    6)
* Python Enhancement Proposals; PEP 487: PEP 487 Simpler customization of class creation.
                                                             (line   32)
* Python Enhancement Proposals; PEP 487 <1>: PEP 487 Descriptor Protocol Enhancements.
                                                             (line    6)
* Python Enhancement Proposals; PEP 487 <2>: PEP 487 Descriptor Protocol Enhancements.
                                                             (line   33)
* Python Enhancement Proposals; PEP 487 <3>: Changes in the Python API<8>.
                                                             (line  103)
* Python Enhancement Proposals; PEP 487 <4>: Documentation<64>.
                                                             (line   52)
* Python Enhancement Proposals; PEP 487 <5>: Documentation<71>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 487 <6>: Core and Builtins<160>.
                                                             (line   46)
* Python Enhancement Proposals; PEP 488: PEP 488 Elimination of PYO files.
                                                             (line    6)
* Python Enhancement Proposals; PEP 488 <1>: PEP 488 Elimination of PYO files.
                                                             (line   19)
* Python Enhancement Proposals; PEP 488 <2>: Changes in the Python API<9>.
                                                             (line   78)
* Python Enhancement Proposals; PEP 488 <3>: Core and Builtins<178>.
                                                             (line   15)
* Python Enhancement Proposals; PEP 488 <4>: Miscellaneous options.
                                                             (line   88)
* Python Enhancement Proposals; PEP 488 <5>: Miscellaneous options.
                                                             (line   90)
* Python Enhancement Proposals; PEP 488 <6>: Miscellaneous options.
                                                             (line   97)
* Python Enhancement Proposals; PEP 488 <7>: Miscellaneous options.
                                                             (line   99)
* Python Enhancement Proposals; PEP 488 <8>: test support import_helper — Utilities for import tests.
                                                             (line   82)
* Python Enhancement Proposals; PEP 488 <9>: Introduction<12>.
                                                             (line   79)
* Python Enhancement Proposals; PEP 488 <10>: importlib util – Utility code for importers.
                                                             (line   24)
* Python Enhancement Proposals; PEP 488 <11>: importlib util – Utility code for importers.
                                                             (line   64)
* Python Enhancement Proposals; PEP 488 <12>: py_compile — Compile Python source files.
                                                             (line   31)
* Python Enhancement Proposals; PEP 489: PEP 489 Multi-phase extension module initialization.
                                                             (line    6)
* Python Enhancement Proposals; PEP 489 <1>: PEP 489 Multi-phase extension module initialization.
                                                             (line   18)
* Python Enhancement Proposals; PEP 489 <2>: Build and C API Changes<3>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 489 <3>: Library<30>.    (line  254)
* Python Enhancement Proposals; PEP 489 <4>: Library<47>.    (line   24)
* Python Enhancement Proposals; PEP 489 <5>: Library<102>.   (line   64)
* Python Enhancement Proposals; PEP 489 <6>: Library<102>.   (line   79)
* Python Enhancement Proposals; PEP 489 <7>: Library<104>.   (line   28)
* Python Enhancement Proposals; PEP 489 <8>: Library<105>.   (line   68)
* Python Enhancement Proposals; PEP 489 <9>: Library<105>.   (line  177)
* Python Enhancement Proposals; PEP 489 <10>: Library<106>.  (line    7)
* Python Enhancement Proposals; PEP 489 <11>: Library<109>.  (line  103)
* Python Enhancement Proposals; PEP 489 <12>: C API<42>.     (line   11)
* Python Enhancement Proposals; PEP 489 <13>: C API<42>.     (line   14)
* Python Enhancement Proposals; PEP 489 <14>: C API<42>.     (line   17)
* Python Enhancement Proposals; PEP 489 <15>: C API<42>.     (line   20)
* Python Enhancement Proposals; PEP 489 <16>: C API<42>.     (line   23)
* Python Enhancement Proposals; PEP 489 <17>: C API<42>.     (line   26)
* Python Enhancement Proposals; PEP 489 <18>: C API<42>.     (line   29)
* Python Enhancement Proposals; PEP 489 <19>: C API<42>.     (line   38)
* Python Enhancement Proposals; PEP 489 <20>: C API<42>.     (line   41)
* Python Enhancement Proposals; PEP 489 <21>: C API<42>.     (line   44)
* Python Enhancement Proposals; PEP 489 <22>: C API<42>.     (line   47)
* Python Enhancement Proposals; PEP 489 <23>: Library<111>.  (line   31)
* Python Enhancement Proposals; PEP 489 <24>: Library<112>.  (line    7)
* Python Enhancement Proposals; PEP 489 <25>: Library<113>.  (line    7)
* Python Enhancement Proposals; PEP 489 <26>: Library<113>.  (line   10)
* Python Enhancement Proposals; PEP 489 <27>: Library<113>.  (line   13)
* Python Enhancement Proposals; PEP 489 <28>: Library<113>.  (line   16)
* Python Enhancement Proposals; PEP 489 <29>: Library<114>.  (line    7)
* Python Enhancement Proposals; PEP 489 <30>: Library<114>.  (line   10)
* Python Enhancement Proposals; PEP 489 <31>: Library<114>.  (line   13)
* Python Enhancement Proposals; PEP 489 <32>: Library<116>.  (line    7)
* Python Enhancement Proposals; PEP 489 <33>: Library<118>.  (line    7)
* Python Enhancement Proposals; PEP 489 <34>: Library<119>.  (line    7)
* Python Enhancement Proposals; PEP 489 <35>: Library<126>.  (line   75)
* Python Enhancement Proposals; PEP 489 <36>: Library<126>.  (line   78)
* Python Enhancement Proposals; PEP 489 <37>: Library<126>.  (line  423)
* Python Enhancement Proposals; PEP 489 <38>: Core and Builtins<125>.
                                                             (line   28)
* Python Enhancement Proposals; PEP 489 <39>: Core and Builtins<125>.
                                                             (line   35)
* Python Enhancement Proposals; PEP 489 <40>: Core and Builtins<125>.
                                                             (line   50)
* Python Enhancement Proposals; PEP 489 <41>: Core and Builtins<126>.
                                                             (line   46)
* Python Enhancement Proposals; PEP 489 <42>: Core and Builtins<126>.
                                                             (line   49)
* Python Enhancement Proposals; PEP 489 <43>: Core and Builtins<126>.
                                                             (line   51)
* Python Enhancement Proposals; PEP 489 <44>: Core and Builtins<126>.
                                                             (line   71)
* Python Enhancement Proposals; PEP 489 <45>: Core and Builtins<126>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 489 <46>: Core and Builtins<127>.
                                                             (line   17)
* Python Enhancement Proposals; PEP 489 <47>: Core and Builtins<127>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 489 <48>: Core and Builtins<127>.
                                                             (line   40)
* Python Enhancement Proposals; PEP 489 <49>: Core and Builtins<127>.
                                                             (line   54)
* Python Enhancement Proposals; PEP 489 <50>: Core and Builtins<127>.
                                                             (line  109)
* Python Enhancement Proposals; PEP 489 <51>: Core and Builtins<127>.
                                                             (line  118)
* Python Enhancement Proposals; PEP 489 <52>: Core and Builtins<128>.
                                                             (line   29)
* Python Enhancement Proposals; PEP 489 <53>: Core and Builtins<128>.
                                                             (line   32)
* Python Enhancement Proposals; PEP 489 <54>: Core and Builtins<128>.
                                                             (line   52)
* Python Enhancement Proposals; PEP 489 <55>: Core and Builtins<128>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 489 <56>: Core and Builtins<128>.
                                                             (line   58)
* Python Enhancement Proposals; PEP 489 <57>: Core and Builtins<129>.
                                                             (line   62)
* Python Enhancement Proposals; PEP 489 <58>: Introduction<12>.
                                                             (line   83)
* Python Enhancement Proposals; PEP 489 <59>: importlib machinery – Importers and path hooks.
                                                             (line   77)
* Python Enhancement Proposals; PEP 489 <60>: importlib machinery – Importers and path hooks.
                                                             (line  298)
* Python Enhancement Proposals; PEP 489 <61>: importlib machinery – Importers and path hooks.
                                                             (line  317)
* Python Enhancement Proposals; PEP 489 <62>: importlib machinery – Importers and path hooks.
                                                             (line  323)
* Python Enhancement Proposals; PEP 489 <63>: importlib util – Utility code for importers.
                                                             (line  183)
* Python Enhancement Proposals; PEP 489 <64>: Creating extensions without third party tools.
                                                             (line   14)
* Python Enhancement Proposals; PEP 489 <65>: Building C and C++ Extensions.
                                                             (line   39)
* Python Enhancement Proposals; PEP 489 <66>: Multi-phase initialization.
                                                             (line  186)
* Python Enhancement Proposals; PEP 489 <67>: Sub-interpreter support.
                                                             (line   81)
* Python Enhancement Proposals; PEP 492: PEP 525 Asynchronous Generators.
                                                             (line    6)
* Python Enhancement Proposals; PEP 492 <1>: New Keywords.   (line    7)
* Python Enhancement Proposals; PEP 492 <2>: PEP 492 - Coroutines with async and await syntax.
                                                             (line    6)
* Python Enhancement Proposals; PEP 492 <3>: PEP 492 - Coroutines with async and await syntax.
                                                             (line   97)
* Python Enhancement Proposals; PEP 492 <4>: New Keywords<2>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 492 <5>: Changes in the C API<7>.
                                                             (line   25)
* Python Enhancement Proposals; PEP 492 <6>: Core and Builtins<145>.
                                                             (line   98)
* Python Enhancement Proposals; PEP 492 <7>: Library<164>.   (line   51)
* Python Enhancement Proposals; PEP 492 <8>: Library<170>.   (line   16)
* Python Enhancement Proposals; PEP 492 <9>: Core and Builtins<175>.
                                                             (line   14)
* Python Enhancement Proposals; PEP 492 <10>: Awaitable Objects.
                                                             (line   33)
* Python Enhancement Proposals; PEP 492 <11>: Yield expressions.
                                                             (line  107)
* Python Enhancement Proposals; PEP 492 <12>: The async with statement.
                                                             (line   45)
* Python Enhancement Proposals; PEP 492 <13>: Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  188)
* Python Enhancement Proposals; PEP 492 <14>: Code Objects Bit Flags.
                                                             (line   38)
* Python Enhancement Proposals; PEP 492 <15>: Code Objects Bit Flags.
                                                             (line   47)
* Python Enhancement Proposals; PEP 492 <16>: Glossary.      (line   92)
* Python Enhancement Proposals; PEP 492 <17>: Glossary.      (line  125)
* Python Enhancement Proposals; PEP 492 <18>: Glossary.      (line  132)
* Python Enhancement Proposals; PEP 492 <19>: Glossary.      (line  141)
* Python Enhancement Proposals; PEP 492 <20>: Glossary.      (line  169)
* Python Enhancement Proposals; PEP 492 <21>: Glossary.      (line  373)
* Python Enhancement Proposals; PEP 492 <22>: Glossary.      (line  380)
* Python Enhancement Proposals; PEP 493: PEP 493 HTTPS verification migration tools for Python 2 7.
                                                             (line    6)
* Python Enhancement Proposals; PEP 494: What’s New In Python 3 6.
                                                             (line   17)
* Python Enhancement Proposals; PEP 495: PEP 495 Local Time Disambiguation.
                                                             (line   13)
* Python Enhancement Proposals; PEP 495 <1>: PEP 495 Local Time Disambiguation.
                                                             (line   36)
* Python Enhancement Proposals; PEP 495 <2>: Library<162>.   (line   96)
* Python Enhancement Proposals; PEP 495 <3>: Using ZoneInfo. (line   34)
* Python Enhancement Proposals; PEP 498: PEP 498 Formatted string literals.
                                                             (line    6)
* Python Enhancement Proposals; PEP 498 <1>: PEP 498 Formatted string literals.
                                                             (line   27)
* Python Enhancement Proposals; PEP 498 <2>: Core and Builtins<163>.
                                                             (line  283)
* Python Enhancement Proposals; PEP 498 <3>: f-strings.      (line  154)
* Python Enhancement Proposals; PEP 498 <4>: Glossary.       (line  546)
* Python Enhancement Proposals; PEP 5:   PEP 230 Warning Framework.
                                                             (line   66)
* Python Enhancement Proposals; PEP 5 <1>: Is it reasonable to propose incompatible changes to Python?.
                                                             (line   14)
* Python Enhancement Proposals; PEP 506: secrets.            (line   19)
* Python Enhancement Proposals; PEP 506 <1>: Library<165>.   (line   60)
* Python Enhancement Proposals; PEP 506 <2>: secrets — Generate secure random numbers for managing secrets.
                                                             (line   23)
* Python Enhancement Proposals; PEP 511: Changes in the Python API<8>.
                                                             (line   33)
* Python Enhancement Proposals; PEP 514: Windows py exe launcher improvements.
                                                             (line    8)
* Python Enhancement Proposals; PEP 514 <1>: Windows<29>.    (line   13)
* Python Enhancement Proposals; PEP 514 <2>: Windows<72>.    (line    8)
* Python Enhancement Proposals; PEP 514 <3>: From the command-line.
                                                             (line   45)
* Python Enhancement Proposals; PEP 515: fractions<3>.       (line    6)
* Python Enhancement Proposals; PEP 515 <1>: PEP 515 Underscores in Numeric Literals.
                                                             (line    6)
* Python Enhancement Proposals; PEP 515 <2>: PEP 515 Underscores in Numeric Literals.
                                                             (line   32)
* Python Enhancement Proposals; PEP 515 <3>: Core and Builtins<159>.
                                                             (line   15)
* Python Enhancement Proposals; PEP 515 <4>: Core and Builtins<159>.
                                                             (line   43)
* Python Enhancement Proposals; PEP 515 <5>: Format specification mini-language.
                                                             (line  146)
* Python Enhancement Proposals; PEP 515 <6>: fractions — Rational numbers.
                                                             (line   94)
* Python Enhancement Proposals; PEP 519: PEP 519 Adding a file system path protocol.
                                                             (line   62)
* Python Enhancement Proposals; PEP 519 <1>: Library<162>.   (line    6)
* Python Enhancement Proposals; PEP 519 <2>: Core and Builtins<162>.
                                                             (line   19)
* Python Enhancement Proposals; PEP 519 <3>: Library<164>.   (line   31)
* Python Enhancement Proposals; PEP 519 <4>: Library<164>.   (line   42)
* Python Enhancement Proposals; PEP 519 <5>: Library<164>.   (line   44)
* Python Enhancement Proposals; PEP 519 <6>: C API<72>.      (line    6)
* Python Enhancement Proposals; PEP 519 <7>: Glossary.       (line 1346)
* Python Enhancement Proposals; PEP 520: PEP 520 Preserving Class Attribute Definition Order.
                                                             (line   17)
* Python Enhancement Proposals; PEP 523: New Features<4>.    (line   19)
* Python Enhancement Proposals; PEP 523 <1>: Porting to Python 3 11<2>.
                                                             (line   33)
* Python Enhancement Proposals; PEP 523 <2>: Porting to Python 3 9<2>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 523 <3>: PEP 523 Adding a frame evaluation API to CPython.
                                                             (line   12)
* Python Enhancement Proposals; PEP 523 <4>: PEP 523 Adding a frame evaluation API to CPython.
                                                             (line   26)
* Python Enhancement Proposals; PEP 523 <5>: Core and Builtins<36>.
                                                             (line   23)
* Python Enhancement Proposals; PEP 523 <6>: Tools/Demos<36>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 523 <7>: Tools/Demos<40>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 523 <8>: Core and Builtins<159>.
                                                             (line   83)
* Python Enhancement Proposals; PEP 523 <9>: Internal Frames.
                                                             (line    6)
* Python Enhancement Proposals; PEP 523 <10>: Low-level API. (line  190)
* Python Enhancement Proposals; PEP 523 <11>: Low-level API. (line  199)
* Python Enhancement Proposals; PEP 524: Summary – Release highlights<6>.
                                                             (line   77)
* Python Enhancement Proposals; PEP 524 <1>: os<8>.          (line   20)
* Python Enhancement Proposals; PEP 524 <2>: os<8>.          (line   25)
* Python Enhancement Proposals; PEP 524 <3>: Library<161>.   (line  150)
* Python Enhancement Proposals; PEP 524 <4>: Library<161>.   (line  154)
* Python Enhancement Proposals; PEP 524 <5>: Random numbers<2>.
                                                             (line   42)
* Python Enhancement Proposals; PEP 525: PEP 525 Asynchronous Generators.
                                                             (line   23)
* Python Enhancement Proposals; PEP 525 <1>: Core and Builtins<159>.
                                                             (line   49)
* Python Enhancement Proposals; PEP 525 <2>: Yield expressions.
                                                             (line  105)
* Python Enhancement Proposals; PEP 525 <3>: Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  188)
* Python Enhancement Proposals; PEP 525 <4>: sys — System-specific parameters and functions.
                                                             (line 1012)
* Python Enhancement Proposals; PEP 525 <5>: sys — System-specific parameters and functions.
                                                             (line 1721)
* Python Enhancement Proposals; PEP 525 <6>: Code Objects Bit Flags.
                                                             (line   56)
* Python Enhancement Proposals; PEP 525 <7>: Asynchronous Generator Objects.
                                                             (line    9)
* Python Enhancement Proposals; PEP 525 <8>: Glossary.       (line  126)
* Python Enhancement Proposals; PEP 526: Other Language Changes<4>.
                                                             (line   56)
* Python Enhancement Proposals; PEP 526 <1>: ast<3>.         (line   18)
* Python Enhancement Proposals; PEP 526 <2>: PEP 563 Postponed Evaluation of Annotations.
                                                             (line    8)
* Python Enhancement Proposals; PEP 526 <3>: PEP 526 Syntax for variable annotations.
                                                             (line   30)
* Python Enhancement Proposals; PEP 526 <4>: typing<9>.      (line   23)
* Python Enhancement Proposals; PEP 526 <5>: Core and Builtins<159>.
                                                             (line   51)
* Python Enhancement Proposals; PEP 526 <6>: Annotated assignment statements.
                                                             (line   42)
* Python Enhancement Proposals; PEP 526 <7>: Function definitions.
                                                             (line  155)
* Python Enhancement Proposals; PEP 526 <8>: Special forms.  (line  197)
* Python Enhancement Proposals; PEP 526 <9>: Other special directives.
                                                             (line   71)
* Python Enhancement Proposals; PEP 526 <10>: dataclasses — Data Classes.
                                                             (line   16)
* Python Enhancement Proposals; PEP 526 <11>: Class variables.
                                                             (line    8)
* Python Enhancement Proposals; PEP 526 <12>: ast Helpers.   (line   18)
* Python Enhancement Proposals; PEP 526 <13>: Compiler Flags.
                                                             (line   30)
* Python Enhancement Proposals; PEP 526 <14>: Glossary.      (line   51)
* Python Enhancement Proposals; PEP 526 <15>: Glossary.      (line 1765)
* Python Enhancement Proposals; PEP 528: PEP 528 Change Windows console encoding to UTF-8.
                                                             (line   17)
* Python Enhancement Proposals; PEP 528 <1>: UTF-8 mode.     (line   34)
* Python Enhancement Proposals; PEP 528 <2>: Global configuration variables.
                                                             (line  172)
* Python Enhancement Proposals; PEP 528 <3>: PyConfig.       (line  538)
* Python Enhancement Proposals; PEP 529: Changes in the Python API<5>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 529 <1>: PEP 529 Change Windows filesystem encoding to UTF-8.
                                                             (line   22)
* Python Enhancement Proposals; PEP 529 <2>: Documentation<27>.
                                                             (line   29)
* Python Enhancement Proposals; PEP 529 <3>: Library<133>.   (line  619)
* Python Enhancement Proposals; PEP 529 <4>: Windows<67>.    (line   14)
* Python Enhancement Proposals; PEP 529 <5>: Environment variables.
                                                             (line  349)
* Python Enhancement Proposals; PEP 529 <6>: UTF-8 mode.     (line   37)
* Python Enhancement Proposals; PEP 529 <7>: Files and Directories.
                                                             (line  302)
* Python Enhancement Proposals; PEP 529 <8>: sys — System-specific parameters and functions.
                                                             (line  796)
* Python Enhancement Proposals; PEP 529 <9>: sys — System-specific parameters and functions.
                                                             (line 1802)
* Python Enhancement Proposals; PEP 529 <10>: File System Encoding.
                                                             (line    7)
* Python Enhancement Proposals; PEP 529 <11>: Global configuration variables.
                                                             (line  154)
* Python Enhancement Proposals; PEP 530: PEP 530 Asynchronous Comprehensions.
                                                             (line    6)
* Python Enhancement Proposals; PEP 530 <1>: PEP 530 Asynchronous Comprehensions.
                                                             (line   19)
* Python Enhancement Proposals; PEP 530 <2>: Core and Builtins<159>.
                                                             (line  145)
* Python Enhancement Proposals; PEP 530 <3>: Displays for lists sets and dictionaries.
                                                             (line   56)
* Python Enhancement Proposals; PEP 538: PEP 538 Legacy C Locale Coercion.
                                                             (line   11)
* Python Enhancement Proposals; PEP 538 <1>: PEP 538 Legacy C Locale Coercion.
                                                             (line   36)
* Python Enhancement Proposals; PEP 538 <2>: PEP 538 Legacy C Locale Coercion.
                                                             (line   48)
* Python Enhancement Proposals; PEP 538 <3>: PEP 540 Forced UTF-8 Runtime Mode.
                                                             (line   27)
* Python Enhancement Proposals; PEP 538 <4>: Documentation<54>.
                                                             (line   68)
* Python Enhancement Proposals; PEP 538 <5>: Documentation<55>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 538 <6>: Core and Builtins<146>.
                                                             (line  134)
* Python Enhancement Proposals; PEP 538 <7>: Environment variables.
                                                             (line  418)
* Python Enhancement Proposals; PEP 538 <8>: General Options.
                                                             (line   88)
* Python Enhancement Proposals; PEP 538 <9>: locale — Internationalization services.
                                                             (line  528)
* Python Enhancement Proposals; PEP 538 <10>: Python Configuration.
                                                             (line   13)
* Python Enhancement Proposals; PEP 539: PEP 539 New C API for Thread-Local Storage.
                                                             (line   12)
* Python Enhancement Proposals; PEP 539 <1>: PEP 539 New C API for Thread-Local Storage.
                                                             (line   30)
* Python Enhancement Proposals; PEP 539 <2>: C API<61>.      (line   13)
* Python Enhancement Proposals; PEP 539 <3>: Thread Specific Storage TSS API.
                                                             (line   15)
* Python Enhancement Proposals; PEP 540: PEP 540 Forced UTF-8 Runtime Mode.
                                                             (line   18)
* Python Enhancement Proposals; PEP 540 <1>: PEP 540 Forced UTF-8 Runtime Mode.
                                                             (line   35)
* Python Enhancement Proposals; PEP 540 <2>: Core and Builtins<143>.
                                                             (line   63)
* Python Enhancement Proposals; PEP 540 <3>: Python UTF-8 Mode.
                                                             (line    6)
* Python Enhancement Proposals; PEP 540 <4>: locale — Internationalization services.
                                                             (line  528)
* Python Enhancement Proposals; PEP 540 <5>: Python Configuration.
                                                             (line   14)
* Python Enhancement Proposals; PEP 544: typing<8>.          (line   32)
* Python Enhancement Proposals; PEP 544 <1>: Nominal vs structural subtyping.
                                                             (line   23)
* Python Enhancement Proposals; PEP 544 <2>: Other special directives.
                                                             (line  157)
* Python Enhancement Proposals; PEP 545: PEP 545 Python Documentation Translations.
                                                             (line    6)
* Python Enhancement Proposals; PEP 545 <1>: PEP 545 Python Documentation Translations.
                                                             (line   20)
* Python Enhancement Proposals; PEP 552: Other CPython Implementation Changes.
                                                             (line   16)
* Python Enhancement Proposals; PEP 552 <1>: PEP 552 Hash-based pyc Files.
                                                             (line   15)
* Python Enhancement Proposals; PEP 552 <2>: PEP 552 Hash-based pyc Files.
                                                             (line   35)
* Python Enhancement Proposals; PEP 552 <3>: Library<138>.   (line  794)
* Python Enhancement Proposals; PEP 552 <4>: Core and Builtins<143>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 552 <5>: Introduction<12>.
                                                             (line   87)
* Python Enhancement Proposals; PEP 552 <6>: py_compile — Compile Python source files.
                                                             (line   82)
* Python Enhancement Proposals; PEP 552 <7>: PyConfig.       (line  271)
* Python Enhancement Proposals; PEP 553: PEP 553 Built-in breakpoint.
                                                             (line   20)
* Python Enhancement Proposals; PEP 553 <1>: Core and Builtins<145>.
                                                             (line   72)
* Python Enhancement Proposals; PEP 554: PEP 684 A Per-Interpreter GIL.
                                                             (line   10)
* Python Enhancement Proposals; PEP 554 <1>: A Per-Interpreter GIL.
                                                             (line   13)
* Python Enhancement Proposals; PEP 557: dataclasses<3>.     (line   26)
* Python Enhancement Proposals; PEP 557 <1>: dataclasses — Data Classes.
                                                             (line   13)
* Python Enhancement Proposals; PEP 560: PEP 560 Core Support for typing module and Generic Types.
                                                             (line   19)
* Python Enhancement Proposals; PEP 560 <1>: types<4>.       (line   12)
* Python Enhancement Proposals; PEP 560 <2>: Core and Builtins<143>.
                                                             (line   66)
* Python Enhancement Proposals; PEP 560 <3>: Resolving MRO entries.
                                                             (line   30)
* Python Enhancement Proposals; PEP 560 <4>: __class_getitem__ versus __getitem__.
                                                             (line   85)
* Python Enhancement Proposals; PEP 560 <5>: Dynamic Type Creation.
                                                             (line   60)
* Python Enhancement Proposals; PEP 560 <6>: Dynamic Type Creation.
                                                             (line   75)
* Python Enhancement Proposals; PEP 560 <7>: Dynamic Type Creation.
                                                             (line  113)
* Python Enhancement Proposals; PEP 562: PEP 562 Customization of Access to Module Attributes.
                                                             (line   16)
* Python Enhancement Proposals; PEP 562 <1>: Library<145>.   (line   63)
* Python Enhancement Proposals; PEP 562 <2>: Core and Builtins<143>.
                                                             (line   69)
* Python Enhancement Proposals; PEP 562 <3>: Customizing module attribute access.
                                                             (line   57)
* Python Enhancement Proposals; PEP 563: PEP 563 may not be the future.
                                                             (line    6)
* Python Enhancement Proposals; PEP 563 <1>: PEP 563 Postponed Evaluation of Annotations.
                                                             (line   51)
* Python Enhancement Proposals; PEP 563 <2>: Library<95>.    (line  300)
* Python Enhancement Proposals; PEP 563 <3>: Core and Builtins<109>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 563 <4>: Future statements.
                                                             (line   34)
* Python Enhancement Proposals; PEP 563 <5>: Function definitions.
                                                             (line  160)
* Python Enhancement Proposals; PEP 563 <6>: Constant.       (line   29)
* Python Enhancement Proposals; PEP 563 <7>: Module Contents<4>.
                                                             (line  131)
* Python Enhancement Proposals; PEP 563 <8>: Module Contents<4>.
                                                             (line   47)
* Python Enhancement Proposals; PEP 564: PEP 564 New Time Functions With Nanosecond Resolution.
                                                             (line    8)
* Python Enhancement Proposals; PEP 564 <1>: PEP 564 New Time Functions With Nanosecond Resolution.
                                                             (line   33)
* Python Enhancement Proposals; PEP 564 <2>: time<5>.        (line    6)
* Python Enhancement Proposals; PEP 564 <3>: Library<147>.   (line  299)
* Python Enhancement Proposals; PEP 565: PEP 565 Show DeprecationWarning in __main__.
                                                             (line   41)
* Python Enhancement Proposals; PEP 565 <1>: Warnings.       (line   23)
* Python Enhancement Proposals; PEP 566: Distribution metadata.
                                                             (line   34)
* Python Enhancement Proposals; PEP 567: contextvars.        (line   20)
* Python Enhancement Proposals; PEP 567 <1>: asyncio<7>.     (line   19)
* Python Enhancement Proposals; PEP 567 <2>: Documentation<54>.
                                                             (line   86)
* Python Enhancement Proposals; PEP 567 <3>: Documentation<56>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 567 <4>: Core and Builtins<142>.
                                                             (line   63)
* Python Enhancement Proposals; PEP 567 <5>: contextvars — Context Variables.
                                                             (line   18)
* Python Enhancement Proposals; PEP 567 <6>: Scheduling callbacks.
                                                             (line   42)
* Python Enhancement Proposals; PEP 567 <7>: Scheduling delayed callbacks.
                                                             (line   35)
* Python Enhancement Proposals; PEP 567 <8>: Scheduling delayed callbacks.
                                                             (line   57)
* Python Enhancement Proposals; PEP 567 <9>: Future Object.  (line  104)
* Python Enhancement Proposals; PEP 570: Positional-only parameters.
                                                             (line   70)
* Python Enhancement Proposals; PEP 570 <1>: Changes in the Python API<5>.
                                                             (line  161)
* Python Enhancement Proposals; PEP 570 <2>: Core and Builtins<133>.
                                                             (line   36)
* Python Enhancement Proposals; PEP 570 <3>: Function definitions.
                                                             (line  107)
* Python Enhancement Proposals; PEP 572: Other Language Changes<2>.
                                                             (line   30)
* Python Enhancement Proposals; PEP 572 <1>: Assignment expressions.
                                                             (line   41)
* Python Enhancement Proposals; PEP 572 <2>: CPython bytecode changes<5>.
                                                             (line   27)
* Python Enhancement Proposals; PEP 572 <3>: Core and Builtins<44>.
                                                             (line   40)
* Python Enhancement Proposals; PEP 572 <4>: Documentation<45>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 572 <5>: Core and Builtins<131>.
                                                             (line  184)
* Python Enhancement Proposals; PEP 572 <6>: Core and Builtins<136>.
                                                             (line   92)
* Python Enhancement Proposals; PEP 572 <7>: Dictionary displays.
                                                             (line   47)
* Python Enhancement Proposals; PEP 572 <8>: Assignment expressions<2>.
                                                             (line   29)
* Python Enhancement Proposals; PEP 572 <9>: Capture Patterns.
                                                             (line   17)
* Python Enhancement Proposals; PEP 572 <10>: Why can’t I use an assignment in an expression?.
                                                             (line   14)
* Python Enhancement Proposals; PEP 573: Summary – Release highlights<4>.
                                                             (line   27)
* Python Enhancement Proposals; PEP 573 <1>: New Features<10>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 573 <2>: Core and Builtins<125>.
                                                             (line   19)
* Python Enhancement Proposals; PEP 573 <3>: C API<45>.      (line   57)
* Python Enhancement Proposals; PEP 574: Pickle protocol 5 with out-of-band data buffers.
                                                             (line   17)
* Python Enhancement Proposals; PEP 574 <1>: Data stream format.
                                                             (line   46)
* Python Enhancement Proposals; PEP 574 <2>: Example<4>.     (line   63)
* Python Enhancement Proposals; PEP 578: PEP 578 Python Runtime Audit Hooks.
                                                             (line   12)
* Python Enhancement Proposals; PEP 578 <1>: Audit events table.
                                                             (line    8)
* Python Enhancement Proposals; PEP 578 <2>: sys — System-specific parameters and functions.
                                                             (line   58)
* Python Enhancement Proposals; PEP 578 <3>: System Functions.
                                                             (line  138)
* Python Enhancement Proposals; PEP 584: Summary – Release highlights<4>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 584 <1>: Dictionary Merge & Update Operators.
                                                             (line   19)
* Python Enhancement Proposals; PEP 584 <2>: Library<128>.   (line  193)
* Python Enhancement Proposals; PEP 584 <3>: Library<128>.   (line  196)
* Python Enhancement Proposals; PEP 584 <4>: Library<128>.   (line  210)
* Python Enhancement Proposals; PEP 584 <5>: Library<129>.   (line   49)
* Python Enhancement Proposals; PEP 584 <6>: Library<129>.   (line   62)
* Python Enhancement Proposals; PEP 584 <7>: Library<129>.   (line  120)
* Python Enhancement Proposals; PEP 584 <8>: Library<129>.   (line  142)
* Python Enhancement Proposals; PEP 584 <9>: ChainMap objects.
                                                             (line   89)
* Python Enhancement Proposals; PEP 584 <10>: defaultdict objects.
                                                             (line   61)
* Python Enhancement Proposals; PEP 584 <11>: OrderedDict objects.
                                                             (line  114)
* Python Enhancement Proposals; PEP 584 <12>: weakref — Weak references.
                                                             (line  199)
* Python Enhancement Proposals; PEP 584 <13>: weakref — Weak references.
                                                             (line  219)
* Python Enhancement Proposals; PEP 584 <14>: Standard Interpreter Types.
                                                             (line  233)
* Python Enhancement Proposals; PEP 584 <15>: Process Parameters.
                                                             (line   54)
* Python Enhancement Proposals; PEP 584 <16>: Process Parameters.
                                                             (line   70)
* Python Enhancement Proposals; PEP 585: Summary – Release highlights<4>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 585 <1>: Type Hinting Generics in Standard Collections.
                                                             (line   18)
* Python Enhancement Proposals; PEP 585 <2>: Library<50>.    (line  158)
* Python Enhancement Proposals; PEP 585 <3>: Library<81>.    (line  124)
* Python Enhancement Proposals; PEP 585 <4>: Documentation<33>.
                                                             (line   31)
* Python Enhancement Proposals; PEP 585 <5>: Special Attributes of GenericAlias objects.
                                                             (line   54)
* Python Enhancement Proposals; PEP 585 <6>: collections abc — Abstract Base Classes for Containers.
                                                             (line   87)
* Python Enhancement Proposals; PEP 585 <7>: Standard Interpreter Types.
                                                             (line  176)
* Python Enhancement Proposals; PEP 585 <8>: Introspection helpers.
                                                             (line  158)
* Python Enhancement Proposals; PEP 585 <9>: Deprecated aliases.
                                                             (line   10)
* Python Enhancement Proposals; PEP 585 <10>: Aliases to built-in types.
                                                             (line   15)
* Python Enhancement Proposals; PEP 585 <11>: Aliases to built-in types.
                                                             (line   27)
* Python Enhancement Proposals; PEP 585 <12>: Aliases to built-in types.
                                                             (line   39)
* Python Enhancement Proposals; PEP 585 <13>: Aliases to built-in types.
                                                             (line   47)
* Python Enhancement Proposals; PEP 585 <14>: Aliases to built-in types.
                                                             (line   58)
* Python Enhancement Proposals; PEP 585 <15>: Aliases to built-in types.
                                                             (line   71)
* Python Enhancement Proposals; PEP 585 <16>: Aliases to types in collections.
                                                             (line   14)
* Python Enhancement Proposals; PEP 585 <17>: Aliases to types in collections.
                                                             (line   25)
* Python Enhancement Proposals; PEP 585 <18>: Aliases to types in collections.
                                                             (line   36)
* Python Enhancement Proposals; PEP 585 <19>: Aliases to types in collections.
                                                             (line   46)
* Python Enhancement Proposals; PEP 585 <20>: Aliases to types in collections.
                                                             (line   56)
* Python Enhancement Proposals; PEP 585 <21>: Aliases to other concrete types.
                                                             (line   18)
* Python Enhancement Proposals; PEP 585 <22>: Aliases to container ABCs in collections abc.
                                                             (line   11)
* Python Enhancement Proposals; PEP 585 <23>: Aliases to container ABCs in collections abc.
                                                             (line   44)
* Python Enhancement Proposals; PEP 585 <24>: Aliases to container ABCs in collections abc.
                                                             (line   52)
* Python Enhancement Proposals; PEP 585 <25>: Aliases to container ABCs in collections abc.
                                                             (line   61)
* Python Enhancement Proposals; PEP 585 <26>: Aliases to container ABCs in collections abc.
                                                             (line   69)
* Python Enhancement Proposals; PEP 585 <27>: Aliases to container ABCs in collections abc.
                                                             (line   77)
* Python Enhancement Proposals; PEP 585 <28>: Aliases to container ABCs in collections abc.
                                                             (line   85)
* Python Enhancement Proposals; PEP 585 <29>: Aliases to container ABCs in collections abc.
                                                             (line   93)
* Python Enhancement Proposals; PEP 585 <30>: Aliases to container ABCs in collections abc.
                                                             (line  102)
* Python Enhancement Proposals; PEP 585 <31>: Aliases to container ABCs in collections abc.
                                                             (line  109)
* Python Enhancement Proposals; PEP 585 <32>: Aliases to container ABCs in collections abc.
                                                             (line  117)
* Python Enhancement Proposals; PEP 585 <33>: Aliases to container ABCs in collections abc.
                                                             (line  125)
* Python Enhancement Proposals; PEP 585 <34>: Aliases to asynchronous ABCs in collections abc.
                                                             (line   18)
* Python Enhancement Proposals; PEP 585 <35>: Aliases to asynchronous ABCs in collections abc.
                                                             (line   33)
* Python Enhancement Proposals; PEP 585 <36>: Aliases to asynchronous ABCs in collections abc.
                                                             (line   46)
* Python Enhancement Proposals; PEP 585 <37>: Aliases to asynchronous ABCs in collections abc.
                                                             (line   56)
* Python Enhancement Proposals; PEP 585 <38>: Aliases to asynchronous ABCs in collections abc.
                                                             (line   66)
* Python Enhancement Proposals; PEP 585 <39>: Aliases to other ABCs in collections abc.
                                                             (line   11)
* Python Enhancement Proposals; PEP 585 <40>: Aliases to other ABCs in collections abc.
                                                             (line   19)
* Python Enhancement Proposals; PEP 585 <41>: Aliases to other ABCs in collections abc.
                                                             (line   31)
* Python Enhancement Proposals; PEP 585 <42>: Aliases to other ABCs in collections abc.
                                                             (line   47)
* Python Enhancement Proposals; PEP 585 <43>: Aliases to other ABCs in collections abc.
                                                             (line   65)
* Python Enhancement Proposals; PEP 585 <44>: Aliases to contextlib ABCs.
                                                             (line   19)
* Python Enhancement Proposals; PEP 585 <45>: Aliases to contextlib ABCs.
                                                             (line   38)
* Python Enhancement Proposals; PEP 585 <46>: Deprecation Timeline of Major Features.
                                                             (line   15)
* Python Enhancement Proposals; PEP 585 <47>: Glossary.      (line  720)
* Python Enhancement Proposals; PEP 586: typing<5>.          (line    8)
* Python Enhancement Proposals; PEP 586 <1>: typing<7>.      (line    6)
* Python Enhancement Proposals; PEP 586 <2>: typing<8>.      (line   18)
* Python Enhancement Proposals; PEP 586 <3>: Special forms.  (line  154)
* Python Enhancement Proposals; PEP 587: Removed C APIs.     (line  104)
* Python Enhancement Proposals; PEP 587 <1>: Deprecated<4>.  (line   34)
* Python Enhancement Proposals; PEP 587 <2>: PEP 587 Python Initialization Configuration.
                                                             (line    6)
* Python Enhancement Proposals; PEP 587 <3>: PEP 587 Python Initialization Configuration.
                                                             (line   83)
* Python Enhancement Proposals; PEP 587 <4>: C API<36>.      (line  125)
* Python Enhancement Proposals; PEP 587 <5>: Core and Builtins<131>.
                                                             (line   76)
* Python Enhancement Proposals; PEP 587 <6>: C API<52>.      (line    6)
* Python Enhancement Proposals; PEP 587 <7>: Python Initialization Configuration.
                                                             (line   32)
* Python Enhancement Proposals; PEP 589: typing<8>.          (line    8)
* Python Enhancement Proposals; PEP 589 <1>: Other special directives.
                                                             (line  466)
* Python Enhancement Proposals; PEP 590: Removed C APIs.     (line  135)
* Python Enhancement Proposals; PEP 590 <1>: Porting to Python 3 11<2>.
                                                             (line   98)
* Python Enhancement Proposals; PEP 590 <2>: Optimizations<4>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 590 <3>: Summary – Release highlights<4>.
                                                             (line   33)
* Python Enhancement Proposals; PEP 590 <4>: Optimizations<5>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 590 <5>: PEP 590 Vectorcall a fast calling protocol for CPython.
                                                             (line   14)
* Python Enhancement Proposals; PEP 590 <6>: Core and Builtins<26>.
                                                             (line  145)
* Python Enhancement Proposals; PEP 590 <7>: Library<39>.    (line 1078)
* Python Enhancement Proposals; PEP 590 <8>: C API<21>.      (line  146)
* Python Enhancement Proposals; PEP 590 <9>: Core and Builtins<49>.
                                                             (line  112)
* Python Enhancement Proposals; PEP 590 <10>: Library<68>.   (line   69)
* Python Enhancement Proposals; PEP 590 <11>: Core and Builtins<71>.
                                                             (line   57)
* Python Enhancement Proposals; PEP 590 <12>: Core and Builtins<80>.
                                                             (line  118)
* Python Enhancement Proposals; PEP 590 <13>: Core and Builtins<89>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 590 <14>: Core and Builtins<95>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 590 <15>: Core and Builtins<95>.
                                                             (line   59)
* Python Enhancement Proposals; PEP 590 <16>: Core and Builtins<110>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 590 <17>: Core and Builtins<110>.
                                                             (line   16)
* Python Enhancement Proposals; PEP 590 <18>: Core and Builtins<126>.
                                                             (line   39)
* Python Enhancement Proposals; PEP 590 <19>: Core and Builtins<126>.
                                                             (line   91)
* Python Enhancement Proposals; PEP 590 <20>: Core and Builtins<127>.
                                                             (line   42)
* Python Enhancement Proposals; PEP 590 <21>: Core and Builtins<127>.
                                                             (line   50)
* Python Enhancement Proposals; PEP 590 <22>: Core and Builtins<127>.
                                                             (line   67)
* Python Enhancement Proposals; PEP 590 <23>: C API<52>.     (line   17)
* Python Enhancement Proposals; PEP 590 <24>: The Vectorcall Protocol.
                                                             (line    8)
* Python Enhancement Proposals; PEP 591: typing<8>.          (line   25)
* Python Enhancement Proposals; PEP 591 <1>: Special forms.  (line  241)
* Python Enhancement Proposals; PEP 591 <2>: Functions and decorators.
                                                             (line  335)
* Python Enhancement Proposals; PEP 593: Summary – Release highlights<4>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 593 <1>: typing<6>.      (line    6)
* Python Enhancement Proposals; PEP 593 <2>: Library<130>.   (line   91)
* Python Enhancement Proposals; PEP 593 <3>: Special forms.  (line  430)
* Python Enhancement Proposals; PEP 593 <4>: Introspection helpers.
                                                             (line   52)
* Python Enhancement Proposals; PEP 594: Summary – Release Highlights.
                                                             (line   21)
* Python Enhancement Proposals; PEP 594 <1>: PEP 594 Remove “dead batteries” from the standard library.
                                                             (line    6)
* Python Enhancement Proposals; PEP 594 <2>: Pending Removal in Python 3 13.
                                                             (line    6)
* Python Enhancement Proposals; PEP 594 <3>: asynchat and asyncore.
                                                             (line    6)
* Python Enhancement Proposals; PEP 594 <4>: smtpd.          (line    6)
* Python Enhancement Proposals; PEP 594 <5>: Summary – Release highlights<2>.
                                                             (line   46)
* Python Enhancement Proposals; PEP 594 <6>: Modules.        (line    6)
* Python Enhancement Proposals; PEP 594 <7>: Library<39>.    (line  844)
* Python Enhancement Proposals; PEP 594 <8>: Library<39>.    (line  847)
* Python Enhancement Proposals; PEP 594 <9>: Library<39>.    (line  850)
* Python Enhancement Proposals; PEP 594 <10>: Library<39>.   (line  858)
* Python Enhancement Proposals; PEP 594 <11>: Library<39>.   (line  862)
* Python Enhancement Proposals; PEP 594 <12>: Library<39>.   (line  868)
* Python Enhancement Proposals; PEP 594 <13>: Library<39>.   (line  871)
* Python Enhancement Proposals; PEP 594 <14>: Library<39>.   (line  886)
* Python Enhancement Proposals; PEP 594 <15>: Library<39>.   (line  889)
* Python Enhancement Proposals; PEP 594 <16>: Library<39>.   (line  896)
* Python Enhancement Proposals; PEP 594 <17>: Library<39>.   (line  899)
* Python Enhancement Proposals; PEP 594 <18>: Library<39>.   (line  902)
* Python Enhancement Proposals; PEP 594 <19>: Library<39>.   (line  905)
* Python Enhancement Proposals; PEP 594 <20>: Library<39>.   (line  908)
* Python Enhancement Proposals; PEP 594 <21>: Library<39>.   (line  963)
* Python Enhancement Proposals; PEP 594 <22>: Library<39>.   (line  966)
* Python Enhancement Proposals; PEP 594 <23>: Library<39>.   (line  969)
* Python Enhancement Proposals; PEP 594 <24>: Library<39>.   (line  972)
* Python Enhancement Proposals; PEP 594 <25>: Library<53>.   (line  105)
* Python Enhancement Proposals; PEP 594 <26>: Library<63>.   (line  683)
* Python Enhancement Proposals; PEP 594 <27>: Library<65>.   (line   94)
* Python Enhancement Proposals; PEP 594 <28>: Library<68>.   (line  124)
* Python Enhancement Proposals; PEP 594 <29>: Library<68>.   (line  150)
* Python Enhancement Proposals; PEP 594 <30>: Tests<31>.     (line   25)
* Python Enhancement Proposals; PEP 594 <31>: Superseded Modules.
                                                             (line   21)
* Python Enhancement Proposals; PEP 594 <32>: aifc — Read and write AIFF and AIFC files.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <33>: asynchat — Asynchronous socket command/response handler.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <34>: asyncore — Asynchronous socket handler.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <35>: audioop — Manipulate raw audio data.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <36>: cgi — Common Gateway Interface support.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <37>: cgitb — Traceback manager for CGI scripts.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <38>: chunk — Read IFF chunked data.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <39>: crypt — Function to check Unix passwords.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <40>: imghdr — Determine the type of an image.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <41>: mailcap — Mailcap file handling.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <42>: msilib — Read and write Microsoft Installer files.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <43>: nis — Interface to Sun’s NIS Yellow Pages.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <44>: nntplib — NNTP protocol client.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <45>: ossaudiodev — Access to OSS-compatible audio devices.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <46>: pipes — Interface to shell pipelines.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <47>: smtpd — SMTP Server.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <48>: sndhdr — Determine type of sound file.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <49>: spwd — The shadow password database.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <50>: sunau — Read and write Sun AU files.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <51>: telnetlib — Telnet client.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <52>: uu — Encode and decode uuencode files.
                                                             (line   10)
* Python Enhancement Proposals; PEP 594 <53>: xdrlib — Encode and decode XDR data.
                                                             (line   10)
* Python Enhancement Proposals; PEP 596: What’s New In Python 3 9.
                                                             (line   16)
* Python Enhancement Proposals; PEP 597: Summary – Release highlights<3>.
                                                             (line   46)
* Python Enhancement Proposals; PEP 597 <1>: Library<97>.    (line   44)
* Python Enhancement Proposals; PEP 597 <2>: Opt-in EncodingWarning.
                                                             (line    6)
* Python Enhancement Proposals; PEP 602: Summary – Release Highlights.
                                                             (line  164)
* Python Enhancement Proposals; PEP 602 <1>: Summary – Release highlights<4>.
                                                             (line   58)
* Python Enhancement Proposals; PEP 602 <2>: How stable is Python?.
                                                             (line    8)
* Python Enhancement Proposals; PEP 604: Summary – Release highlights<3>.
                                                             (line   27)
* Python Enhancement Proposals; PEP 604 <1>: PEP 604 New Type Union Operator.
                                                             (line   28)
* Python Enhancement Proposals; PEP 604 <2>: Library<105>.   (line   25)
* Python Enhancement Proposals; PEP 604 <3>: Documentation<42>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 604 <4>: Union Type.     (line  104)
* Python Enhancement Proposals; PEP 604 <5>: Manually Un-Stringizing Stringized Annotations.
                                                             (line   42)
* Python Enhancement Proposals; PEP 610: Distributions.      (line   49)
* Python Enhancement Proposals; PEP 612: Summary – Release highlights<3>.
                                                             (line   29)
* Python Enhancement Proposals; PEP 612 <1>: PEP 612 Parameter Specification Variables.
                                                             (line   25)
* Python Enhancement Proposals; PEP 612 <2>: Library<92>.    (line  691)
* Python Enhancement Proposals; PEP 612 <3>: Library<95>.    (line   95)
* Python Enhancement Proposals; PEP 612 <4>: Library<104>.   (line   17)
* Python Enhancement Proposals; PEP 612 <5>: Library<105>.   (line   25)
* Python Enhancement Proposals; PEP 612 <6>: Library<105>.   (line  119)
* Python Enhancement Proposals; PEP 612 <7>: Annotating callable objects.
                                                             (line   77)
* Python Enhancement Proposals; PEP 612 <8>: User-defined generic types.
                                                             (line  179)
* Python Enhancement Proposals; PEP 612 <9>: Special forms.  (line  125)
* Python Enhancement Proposals; PEP 612 <10>: Building generic types and type aliases.
                                                             (line  464)
* Python Enhancement Proposals; PEP 612 <11>: Aliases to other ABCs in collections abc.
                                                             (line   35)
* Python Enhancement Proposals; PEP 613: Summary – Release highlights<3>.
                                                             (line   31)
* Python Enhancement Proposals; PEP 613 <1>: PEP 613 TypeAlias.
                                                             (line   21)
* Python Enhancement Proposals; PEP 613 <2>: Library<111>.   (line   98)
* Python Enhancement Proposals; PEP 613 <3>: Special types.  (line  228)
* Python Enhancement Proposals; PEP 614: Summary – Release highlights<4>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 614 <1>: Other Language Changes<5>.
                                                             (line   38)
* Python Enhancement Proposals; PEP 614 <2>: Core and Builtins<127>.
                                                             (line  112)
* Python Enhancement Proposals; PEP 614 <3>: Function definitions.
                                                             (line   57)
* Python Enhancement Proposals; PEP 614 <4>: Class definitions.
                                                             (line   60)
* Python Enhancement Proposals; PEP 615: Summary – Release highlights<4>.
                                                             (line   50)
* Python Enhancement Proposals; PEP 615 <1>: zoneinfo.       (line   37)
* Python Enhancement Proposals; PEP 615 <2>: Library<127>.   (line   54)
* Python Enhancement Proposals; PEP 615 <3>: zoneinfo — IANA time zone support.
                                                             (line   13)
* Python Enhancement Proposals; PEP 616: Summary – Release highlights<4>.
                                                             (line   16)
* Python Enhancement Proposals; PEP 616 <1>: New String Methods to Remove Prefixes and Suffixes.
                                                             (line    9)
* Python Enhancement Proposals; PEP 616 <2>: Core and Builtins<126>.
                                                             (line   82)
* Python Enhancement Proposals; PEP 617: PEP 701 Syntactic formalization of f-strings.
                                                             (line   69)
* Python Enhancement Proposals; PEP 617 <1>: Modules.        (line   30)
* Python Enhancement Proposals; PEP 617 <2>: Parenthesized context managers.
                                                             (line   45)
* Python Enhancement Proposals; PEP 617 <3>: Summary – Release highlights<4>.
                                                             (line   30)
* Python Enhancement Proposals; PEP 617 <4>: New Parser.     (line   21)
* Python Enhancement Proposals; PEP 617 <5>: Deprecated<7>.  (line   95)
* Python Enhancement Proposals; PEP 617 <6>: Library<92>.    (line  178)
* Python Enhancement Proposals; PEP 617 <7>: Library<128>.   (line   34)
* Python Enhancement Proposals; PEP 617 <8>: Full Grammar specification.
                                                             (line   16)
* Python Enhancement Proposals; PEP 618: Summary – Release highlights<3>.
                                                             (line   19)
* Python Enhancement Proposals; PEP 618 <1>: Other Language Changes<4>.
                                                             (line   17)
* Python Enhancement Proposals; PEP 618 <2>: Core and Builtins<121>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 623: Summary – Release highlights.
                                                             (line  107)
* Python Enhancement Proposals; PEP 623 <1>: Optimizations<2>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 623 <2>: Removed<2>.     (line   11)
* Python Enhancement Proposals; PEP 623 <3>: Summary – Release highlights<3>.
                                                             (line   41)
* Python Enhancement Proposals; PEP 623 <4>: C API<29>.      (line   21)
* Python Enhancement Proposals; PEP 623 <5>: Core and Builtins<96>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 623 <6>: Documentation<37>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 623 <7>: Unicode Objects.
                                                             (line   17)
* Python Enhancement Proposals; PEP 624: Summary – Release highlights<2>.
                                                             (line   49)
* Python Enhancement Proposals; PEP 624 <1>: Removed<4>.     (line   97)
* Python Enhancement Proposals; PEP 624 <2>: Summary – Release highlights<3>.
                                                             (line   44)
* Python Enhancement Proposals; PEP 624 <3>: C API<36>.      (line  143)
* Python Enhancement Proposals; PEP 624#alternative-apis: Removed<4>.
                                                             (line   97)
* Python Enhancement Proposals; PEP 626: Pending Removal in Python 3 15.
                                                             (line   77)
* Python Enhancement Proposals; PEP 626 <1>: Deprecated.     (line  229)
* Python Enhancement Proposals; PEP 626 <2>: Pending Removal in Python 3 15<3>.
                                                             (line   77)
* Python Enhancement Proposals; PEP 626 <3>: Summary – Release highlights<3>.
                                                             (line   23)
* Python Enhancement Proposals; PEP 626 <4>: Core and Builtins<57>.
                                                             (line   45)
* Python Enhancement Proposals; PEP 626 <5>: Methods on code objects.
                                                             (line   81)
* Python Enhancement Proposals; PEP 626 <6>: Analysis functions.
                                                             (line  173)
* Python Enhancement Proposals; PEP 626 <7>: Pending Removal in Python 3 15<5>.
                                                             (line   77)
* Python Enhancement Proposals; PEP 628: cmath.              (line    7)
* Python Enhancement Proposals; PEP 628 <1>: math<7>.        (line    7)
* Python Enhancement Proposals; PEP 628 <2>: Library<162>.   (line   32)
* Python Enhancement Proposals; PEP 632: Summary – Release highlights.
                                                             (line  111)
* Python Enhancement Proposals; PEP 632 <1>: distutils.      (line    7)
* Python Enhancement Proposals; PEP 632 <2>: Summary – Release highlights<3>.
                                                             (line   39)
* Python Enhancement Proposals; PEP 632 <3>: distutils<2>.   (line   14)
* Python Enhancement Proposals; PEP 632 <4>: Library<53>.    (line   41)
* Python Enhancement Proposals; PEP 632 <5>: distutils — Building and installing Python modules.
                                                             (line   10)
* Python Enhancement Proposals; PEP 634: Summary – Release highlights<3>.
                                                             (line    8)
* Python Enhancement Proposals; PEP 634 <1>: Other Key Features.
                                                             (line   53)
* Python Enhancement Proposals; PEP 634 <2>: Core and Builtins<61>.
                                                             (line   55)
* Python Enhancement Proposals; PEP 634 <3>: Core and Builtins<92>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 634 <4>: Core and Builtins<97>.
                                                             (line   16)
* Python Enhancement Proposals; PEP 634 <5>: Customizing positional arguments in class pattern matching.
                                                             (line   32)
* Python Enhancement Proposals; PEP 634 <6>: The match statement.
                                                             (line   33)
* Python Enhancement Proposals; PEP 634 <7>: Class Patterns. (line  136)
* Python Enhancement Proposals; PEP 634 <8>: PyTypeObject Slots.
                                                             (line  846)
* Python Enhancement Proposals; PEP 634 <9>: PyTypeObject Slots.
                                                             (line  870)
* Python Enhancement Proposals; PEP 635: Summary – Release highlights<3>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 635 <1>: Other Key Features.
                                                             (line   54)
* Python Enhancement Proposals; PEP 636: Summary – Release highlights<3>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 636 <1>: Other Key Features.
                                                             (line   54)
* Python Enhancement Proposals; PEP 636 <2>: match Statements.
                                                             (line  180)
* Python Enhancement Proposals; PEP 636 <3>: The match statement.
                                                             (line   35)
* Python Enhancement Proposals; PEP 636 <4>: Class Patterns. (line  138)
* Python Enhancement Proposals; PEP 644: hashlib.            (line    8)
* Python Enhancement Proposals; PEP 644 <1>: Summary – Release highlights<3>.
                                                             (line   37)
* Python Enhancement Proposals; PEP 644 <2>: hashlib<3>.     (line    7)
* Python Enhancement Proposals; PEP 644 <3>: ssl<3>.         (line    7)
* Python Enhancement Proposals; PEP 644 <4>: Build Changes<4>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 644 <5>: Core and Builtins<33>.
                                                             (line  167)
* Python Enhancement Proposals; PEP 644 <6>: Library<63>.    (line  525)
* Python Enhancement Proposals; PEP 644 <7>: Build<42>.      (line    9)
* Python Enhancement Proposals; PEP 644 <8>: ssl — TLS/SSL wrapper for socket objects.
                                                             (line   57)
* Python Enhancement Proposals; PEP 646: PEP 646 Variadic generics.
                                                             (line    7)
* Python Enhancement Proposals; PEP 646 <1>: PEP 646 Variadic generics.
                                                             (line   18)
* Python Enhancement Proposals; PEP 646 <2>: Library.        (line  189)
* Python Enhancement Proposals; PEP 646 <3>: Subscriptions.  (line   30)
* Python Enhancement Proposals; PEP 646 <4>: Expression lists.
                                                             (line   27)
* Python Enhancement Proposals; PEP 646 <5>: Function definitions.
                                                             (line  126)
* Python Enhancement Proposals; PEP 646 <6>: Building generic types and type aliases.
                                                             (line  320)
* Python Enhancement Proposals; PEP 647: Summary – Release highlights<3>.
                                                             (line   33)
* Python Enhancement Proposals; PEP 647 <1>: PEP 647 User-Defined Type Guards.
                                                             (line    9)
* Python Enhancement Proposals; PEP 647 <2>: Library<95>.    (line  182)
* Python Enhancement Proposals; PEP 647 <3>: Special forms.  (line  544)
* Python Enhancement Proposals; PEP 649: Annotation scopes.  (line   10)
* Python Enhancement Proposals; PEP 649 <1>: Module Contents<4>.
                                                             (line  132)
* Python Enhancement Proposals; PEP 652: PEP 652 Maintaining the Stable ABI.
                                                             (line   11)
* Python Enhancement Proposals; PEP 652 <1>: C API<37>.      (line   41)
* Python Enhancement Proposals; PEP 654: PEP 654 Exception Groups and except*.
                                                             (line    6)
* Python Enhancement Proposals; PEP 654 <1>: PEP 654 Exception Groups and except*.
                                                             (line   13)
* Python Enhancement Proposals; PEP 654 <2>: New opcodes.    (line   18)
* Python Enhancement Proposals; PEP 654 <3>: Core and Builtins<54>.
                                                             (line   23)
* Python Enhancement Proposals; PEP 654 <4>: Core and Builtins<77>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 654 <5>: Core and Builtins<80>.
                                                             (line   88)
* Python Enhancement Proposals; PEP 655: PEP 655 Marking individual TypedDict items as required or not-required.
                                                             (line   30)
* Python Enhancement Proposals; PEP 655 <1>: Library<65>.    (line  266)
* Python Enhancement Proposals; PEP 655 <2>: Special forms.  (line  255)
* Python Enhancement Proposals; PEP 655 <3>: Special forms.  (line  264)
* Python Enhancement Proposals; PEP 655 <4>: Other special directives.
                                                             (line  475)
* Python Enhancement Proposals; PEP 657: PEP 657 Fine-grained error locations in tracebacks.
                                                             (line   55)
* Python Enhancement Proposals; PEP 657 <1>: inspect<2>.     (line   17)
* Python Enhancement Proposals; PEP 657 <2>: Library<65>.    (line  223)
* Python Enhancement Proposals; PEP 657 <3>: Core and Builtins<88>.
                                                             (line   11)
* Python Enhancement Proposals; PEP 659: PEP 659 Specializing Adaptive Interpreter.
                                                             (line    6)
* Python Enhancement Proposals; PEP 659 <1>: PEP 659 Specializing Adaptive Interpreter.
                                                             (line   30)
* Python Enhancement Proposals; PEP 659 <2>: Single-threaded performance.
                                                             (line   10)
* Python Enhancement Proposals; PEP 667: Summary – Release Highlights.
                                                             (line   40)
* Python Enhancement Proposals; PEP 667 <1>: Defined mutation semantics for locals.
                                                             (line    8)
* Python Enhancement Proposals; PEP 667 <2>: Defined mutation semantics for locals.
                                                             (line   41)
* Python Enhancement Proposals; PEP 667 <3>: Deprecated C APIs.
                                                             (line   33)
* Python Enhancement Proposals; PEP 667 <4>: Changes in the Python API.
                                                             (line   17)
* Python Enhancement Proposals; PEP 667 <5>: Changes in the Python API.
                                                             (line   26)
* Python Enhancement Proposals; PEP 667 <6>: Changes in the Python API.
                                                             (line   32)
* Python Enhancement Proposals; PEP 667 <7>: Built-in Functions.
                                                             (line 1147)
* Python Enhancement Proposals; PEP 667 <8>: Command-line interface<6>.
                                                             (line   61)
* Python Enhancement Proposals; PEP 667 <9>: Reflection.     (line   44)
* Python Enhancement Proposals; PEP 667 <10>: Frame Objects. (line  138)
* Python Enhancement Proposals; PEP 667 <11>: Frame Locals Proxies.
                                                             (line   14)
* Python Enhancement Proposals; PEP 667 <12>: Legacy Local Variable APIs.
                                                             (line   45)
* Python Enhancement Proposals; PEP 669: Summary – Release Highlights.
                                                             (line  110)
* Python Enhancement Proposals; PEP 669 <1>: New Features<2>.
                                                             (line    6)
* Python Enhancement Proposals; PEP 669 <2>: PEP 669 Low impact monitoring for CPython.
                                                             (line    6)
* Python Enhancement Proposals; PEP 669 <3>: Core and Builtins<38>.
                                                             (line   17)
* Python Enhancement Proposals; PEP 670: Summary – Release highlights<2>.
                                                             (line   51)
* Python Enhancement Proposals; PEP 670 <1>: Porting to Python 3 11<2>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 673: PEP 673 Self type.  (line   32)
* Python Enhancement Proposals; PEP 673 <1>: Library<72>.    (line  134)
* Python Enhancement Proposals; PEP 673 <2>: Special types.  (line  194)
* Python Enhancement Proposals; PEP 675: PEP 675 Arbitrary literal string type.
                                                             (line   32)
* Python Enhancement Proposals; PEP 675 <1>: Library<68>.    (line   59)
* Python Enhancement Proposals; PEP 675 <2>: Special types.  (line   95)
* Python Enhancement Proposals; PEP 676: Documentation<28>.  (line    8)
* Python Enhancement Proposals; PEP 678: Other Language Changes<2>.
                                                             (line   35)
* Python Enhancement Proposals; PEP 678 <1>: PEP 678 Exceptions can be enriched with notes.
                                                             (line   11)
* Python Enhancement Proposals; PEP 678 <2>: Core and Builtins<37>.
                                                             (line   48)
* Python Enhancement Proposals; PEP 678 <3>: Core and Builtins<40>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 678 <4>: Core and Builtins<61>.
                                                             (line  118)
* Python Enhancement Proposals; PEP 680: Summary – Release highlights<2>.
                                                             (line   20)
* Python Enhancement Proposals; PEP 680 <1>: New Modules<3>. (line    6)
* Python Enhancement Proposals; PEP 680 <2>: Library<68>.    (line  205)
* Python Enhancement Proposals; PEP 681: PEP 681 Data class transforms.
                                                             (line   30)
* Python Enhancement Proposals; PEP 681 <1>: Library<65>.    (line  110)
* Python Enhancement Proposals; PEP 681 <2>: Functions and decorators.
                                                             (line  243)
* Python Enhancement Proposals; PEP 682: Other Language Changes<3>.
                                                             (line   49)
* Python Enhancement Proposals; PEP 682 <1>: Format specification mini-language.
                                                             (line   94)
* Python Enhancement Proposals; PEP 683: New Features<4>.    (line  147)
* Python Enhancement Proposals; PEP 683 <1>: Core and Builtins<36>.
                                                             (line   70)
* Python Enhancement Proposals; PEP 683 <2>: Reference Counting.
                                                             (line  122)
* Python Enhancement Proposals; PEP 683 <3>: Glossary.       (line  794)
* Python Enhancement Proposals; PEP 684: PEP 684 A Per-Interpreter GIL.
                                                             (line    6)
* Python Enhancement Proposals; PEP 684 <1>: New Features<4>.
                                                             (line  182)
* Python Enhancement Proposals; PEP 684 <2>: High-level API. (line   21)
* Python Enhancement Proposals; PEP 684 <3>: A Per-Interpreter GIL.
                                                             (line   14)
* Python Enhancement Proposals; PEP 686: Python UTF-8 Mode.  (line   70)
* Python Enhancement Proposals; PEP 686 <1>: Text Encoding.  (line   32)
* Python Enhancement Proposals; PEP 687: Library<35>.        (line  137)
* Python Enhancement Proposals; PEP 687 <1>: Core and Builtins<35>.
                                                             (line  326)
* Python Enhancement Proposals; PEP 687 <2>: Library<43>.    (line  293)
* Python Enhancement Proposals; PEP 687 <3>: Library<43>.    (line  300)
* Python Enhancement Proposals; PEP 687 <4>: Library<43>.    (line  333)
* Python Enhancement Proposals; PEP 687 <5>: Library<43>.    (line  336)
* Python Enhancement Proposals; PEP 687 <6>: Library<43>.    (line  346)
* Python Enhancement Proposals; PEP 687 <7>: Library<43>.    (line  403)
* Python Enhancement Proposals; PEP 687 <8>: Library<45>.    (line    6)
* Python Enhancement Proposals; PEP 687 <9>: Library<46>.    (line  111)
* Python Enhancement Proposals; PEP 687 <10>: Library<46>.   (line  118)
* Python Enhancement Proposals; PEP 688: PEP 688 Making the buffer protocol accessible in Python.
                                                             (line    6)
* Python Enhancement Proposals; PEP 688 <1>: Core and Builtins<38>.
                                                             (line   25)
* Python Enhancement Proposals; PEP 688 <2>: Emulating buffer types.
                                                             (line   38)
* Python Enhancement Proposals; PEP 688 <3>: Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  198)
* Python Enhancement Proposals; PEP 688#current-options: Pending removal in Python 3 17.
                                                             (line   26)
* Python Enhancement Proposals; PEP 688#current-options <1>: Pending removal in Python 3 17.
                                                             (line   58)
* Python Enhancement Proposals; PEP 688#current-options <2>: Deprecated.
                                                             (line   73)
* Python Enhancement Proposals; PEP 688#current-options <3>: Pending removal in Python 3 17<2>.
                                                             (line   26)
* Python Enhancement Proposals; PEP 688#current-options <4>: Pending removal in Python 3 17<2>.
                                                             (line   58)
* Python Enhancement Proposals; PEP 688#current-options <5>: Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  112)
* Python Enhancement Proposals; PEP 688#current-options <6>: Aliases to container ABCs in collections abc.
                                                             (line   33)
* Python Enhancement Proposals; PEP 688#current-options <7>: Pending removal in Python 3 17<3>.
                                                             (line   26)
* Python Enhancement Proposals; PEP 688#current-options <8>: Pending removal in Python 3 17<3>.
                                                             (line   58)
* Python Enhancement Proposals; PEP 689: C API<24>.          (line   26)
* Python Enhancement Proposals; PEP 692: PEP 692 Using TypedDict for more precise **kwargs typing.
                                                             (line   10)
* Python Enhancement Proposals; PEP 692 <1>: PEP 692 Using TypedDict for more precise **kwargs typing.
                                                             (line   21)
* Python Enhancement Proposals; PEP 692 <2>: Library<43>.    (line  120)
* Python Enhancement Proposals; PEP 692 <3>: Documentation<19>.
                                                             (line   11)
* Python Enhancement Proposals; PEP 692 <4>: Special forms.  (line  624)
* Python Enhancement Proposals; PEP 693: What’s New In Python 3 12.
                                                             (line   16)
* Python Enhancement Proposals; PEP 695: PEP 695 Type Parameter Syntax.
                                                             (line   10)
* Python Enhancement Proposals; PEP 695 <1>: PEP 695 Type Parameter Syntax.
                                                             (line   61)
* Python Enhancement Proposals; PEP 695 <2>: CPython bytecode changes.
                                                             (line   41)
* Python Enhancement Proposals; PEP 695 <3>: Library<27>.    (line   76)
* Python Enhancement Proposals; PEP 695 <4>: Library<30>.    (line  123)
* Python Enhancement Proposals; PEP 695 <5>: Library<39>.    (line   95)
* Python Enhancement Proposals; PEP 695 <6>: Library<39>.    (line  660)
* Python Enhancement Proposals; PEP 695 <7>: Library<39>.    (line  855)
* Python Enhancement Proposals; PEP 695 <8>: Library<39>.    (line  948)
* Python Enhancement Proposals; PEP 695 <9>: Core and Builtins<36>.
                                                             (line   10)
* Python Enhancement Proposals; PEP 695 <10>: Core and Builtins<36>.
                                                             (line  105)
* Python Enhancement Proposals; PEP 695 <11>: Library<43>.   (line   10)
* Python Enhancement Proposals; PEP 695 <12>: Annotation scopes.
                                                             (line   55)
* Python Enhancement Proposals; PEP 695 <13>: The type statement.
                                                             (line   40)
* Python Enhancement Proposals; PEP 695 <14>: Special types. (line   60)
* Python Enhancement Proposals; PEP 695 <15>: Building generic types and type aliases.
                                                             (line  113)
* Python Enhancement Proposals; PEP 695 <16>: Building generic types and type aliases.
                                                             (line  212)
* Python Enhancement Proposals; PEP 695 <17>: Building generic types and type aliases.
                                                             (line  346)
* Python Enhancement Proposals; PEP 695 <18>: Building generic types and type aliases.
                                                             (line  453)
* Python Enhancement Proposals; PEP 695 <19>: Deprecation Timeline of Major Features.
                                                             (line   30)
* Python Enhancement Proposals; PEP 696: Summary – Release Highlights.
                                                             (line  115)
* Python Enhancement Proposals; PEP 696 <1>: Core and Builtins<26>.
                                                             (line  165)
* Python Enhancement Proposals; PEP 696 <2>: Annotation scopes.
                                                             (line   58)
* Python Enhancement Proposals; PEP 696 <3>: Type parameter lists.
                                                             (line    8)
* Python Enhancement Proposals; PEP 697: New Features<4>.    (line    6)
* Python Enhancement Proposals; PEP 697 <1>: New Features<4>.
                                                             (line   33)
* Python Enhancement Proposals; PEP 697 <2>: C API<22>.      (line   38)
* Python Enhancement Proposals; PEP 698: PEP 698 Override Decorator for Static Typing.
                                                             (line   30)
* Python Enhancement Proposals; PEP 698 <1>: Library<46>.    (line  100)
* Python Enhancement Proposals; PEP 698 <2>: Functions and decorators.
                                                             (line  407)
* Python Enhancement Proposals; PEP 699: Pending Removal in Python 3 14<2>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 699 <1>: Deprecated<2>.  (line    6)
* Python Enhancement Proposals; PEP 699 <2>: Pending Removal in Python 3 14<4>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 699 <3>: Build<26>.      (line   15)
* Python Enhancement Proposals; PEP 699 <4>: Pending Removal in Python 3 14<6>.
                                                             (line    7)
* Python Enhancement Proposals; PEP 7:   Build and C API Changes<2>.
                                                             (line    9)
* Python Enhancement Proposals; PEP 7 <1>: Build Requirements.
                                                             (line   51)
* Python Enhancement Proposals; PEP 7 <2>: Coding standards. (line    7)
* Python Enhancement Proposals; PEP 7 <3>: Useful macros.    (line  301)
* Python Enhancement Proposals; PEP 7 <4>: Useful macros.    (line  319)
* Python Enhancement Proposals; PEP 701: PEP 701 Syntactic formalization of f-strings.
                                                             (line    6)
* Python Enhancement Proposals; PEP 701 <1>: PEP 701 Syntactic formalization of f-strings.
                                                             (line   66)
* Python Enhancement Proposals; PEP 701 <2>: tokenize.       (line    6)
* Python Enhancement Proposals; PEP 701 <3>: Optimizations<2>.
                                                             (line   26)
* Python Enhancement Proposals; PEP 701 <4>: Changes in the Python API<2>.
                                                             (line   75)
* Python Enhancement Proposals; PEP 701 <5>: Changes in the Python API<2>.
                                                             (line   77)
* Python Enhancement Proposals; PEP 701 <6>: Changes in the Python API<2>.
                                                             (line   99)
* Python Enhancement Proposals; PEP 702: Summary – Release Highlights.
                                                             (line  119)
* Python Enhancement Proposals; PEP 702 <1>: warnings.       (line    6)
* Python Enhancement Proposals; PEP 702 <2>: Library<37>.    (line  469)
* Python Enhancement Proposals; PEP 702 <3>: Available Functions.
                                                             (line  187)
* Python Enhancement Proposals; PEP 703: Summary – Release Highlights.
                                                             (line   10)
* Python Enhancement Proposals; PEP 703 <1>: Summary – Release Highlights.
                                                             (line   46)
* Python Enhancement Proposals; PEP 703 <2>: Free-threaded CPython.
                                                             (line   54)
* Python Enhancement Proposals; PEP 703 <3>: Core and Builtins<29>.
                                                             (line   11)
* Python Enhancement Proposals; PEP 703 <4>: C API<20>.      (line  137)
* Python Enhancement Proposals; PEP 703 <5>: Installing Free-threaded Binaries.
                                                             (line   11)
* Python Enhancement Proposals; PEP 703 <6>: Installing Free-threaded Binaries<2>.
                                                             (line   12)
* Python Enhancement Proposals; PEP 703 <7>: GIL and performance considerations.
                                                             (line   16)
* Python Enhancement Proposals; PEP 703 <8>: Python experimental support for free threading.
                                                             (line   25)
* Python Enhancement Proposals; PEP 703 <9>: Can’t we get rid of the Global Interpreter Lock?.
                                                             (line   12)
* Python Enhancement Proposals; PEP 703 <10>: Glossary.      (line  613)
* Python Enhancement Proposals; PEP 703 <11>: Glossary.      (line  748)
* Python Enhancement Proposals; PEP 705: Summary – Release Highlights.
                                                             (line  123)
* Python Enhancement Proposals; PEP 705 <1>: typing.         (line    6)
* Python Enhancement Proposals; PEP 705 <2>: Library<35>.    (line   17)
* Python Enhancement Proposals; PEP 705 <3>: Special forms.  (line  285)
* Python Enhancement Proposals; PEP 706: Other Language Changes<2>.
                                                             (line   77)
* Python Enhancement Proposals; PEP 706 <1>: tarfile<2>.     (line   13)
* Python Enhancement Proposals; PEP 706 <2>: tarfile<3>.     (line   13)
* Python Enhancement Proposals; PEP 706 <3>: tarfile<4>.     (line   13)
* Python Enhancement Proposals; PEP 706 <4>: tarfile<6>.     (line   13)
* Python Enhancement Proposals; PEP 706 <5>: Extraction filters.
                                                             (line   22)
* Python Enhancement Proposals; PEP 709: Changes in the Python API.
                                                             (line   26)
* Python Enhancement Proposals; PEP 709 <1>: PEP 709 Comprehension inlining.
                                                             (line    9)
* Python Enhancement Proposals; PEP 709 <2>: PEP 709 Comprehension inlining.
                                                             (line   35)
* Python Enhancement Proposals; PEP 709 <3>: CPython bytecode changes.
                                                             (line   33)
* Python Enhancement Proposals; PEP 709 <4>: Core and Builtins<38>.
                                                             (line   27)
* Python Enhancement Proposals; PEP 709 <5>: Built-in Functions.
                                                             (line 1145)
* Python Enhancement Proposals; PEP 719: What’s New In Python 3 13.
                                                             (line   16)
* Python Enhancement Proposals; PEP 730: Summary – Release Highlights.
                                                             (line  133)
* Python Enhancement Proposals; PEP 730 <1>: Support for mobile platforms.
                                                             (line    6)
* Python Enhancement Proposals; PEP 730 <2>: Support for mobile platforms.
                                                             (line   25)
* Python Enhancement Proposals; PEP 734: Library<30>.        (line  161)
* Python Enhancement Proposals; PEP 737: Changed C APIs.     (line   44)
* Python Enhancement Proposals; PEP 737 <1>: C API<16>.      (line    6)
* Python Enhancement Proposals; PEP 737 <2>: C API<16>.      (line   49)
* Python Enhancement Proposals; PEP 738: Summary – Release Highlights.
                                                             (line  136)
* Python Enhancement Proposals; PEP 738 <1>: Support for mobile platforms.
                                                             (line   15)
* Python Enhancement Proposals; PEP 738 <2>: Support for mobile platforms.
                                                             (line   25)
* Python Enhancement Proposals; PEP 738 <3>: Library<30>.    (line   54)
* Python Enhancement Proposals; PEP 742: Summary – Release Highlights.
                                                             (line  127)
* Python Enhancement Proposals; PEP 742 <1>: typing.         (line    9)
* Python Enhancement Proposals; PEP 742 <2>: Library<30>.    (line  239)
* Python Enhancement Proposals; PEP 742 <3>: Special forms.  (line  522)
* Python Enhancement Proposals; PEP 744: Summary – Release Highlights.
                                                             (line   11)
* Python Enhancement Proposals; PEP 744 <1>: Summary – Release Highlights.
                                                             (line   50)
* Python Enhancement Proposals; PEP 744 <2>: An experimental just-in-time JIT compiler.
                                                             (line   62)
* Python Enhancement Proposals; PEP 8:   Library Changes.    (line   26)
* Python Enhancement Proposals; PEP 8 <1>: Library<147>.     (line  124)
* Python Enhancement Proposals; PEP 8 <2>: IDLE<67>.         (line   81)
* Python Enhancement Proposals; PEP 8 <3>: Intermezzo Coding Style.
                                                             (line   13)
* Python Enhancement Proposals; PEP 8 <4>: Editors and IDEs. (line    7)
* Python Enhancement Proposals; PEP 8 <5>: Value comparisons.
                                                             (line   61)
* Python Enhancement Proposals; PEP 8 <6>: Built-in Functions.
                                                             (line 1826)
* Python Enhancement Proposals; PEP 8 <7>: Odds and Ends<2>. (line   35)
* Python Enhancement Proposals; PEP 8 <8>: Are there coding standards or a style guide for Python programs?.
                                                             (line    7)
* Python Enhancement Proposals; PEP 8 <9>: When can I rely on identity tests with the is operator?.
                                                             (line   59)
* Python Enhancement Proposals; PEP 8 <10>: How do I keep editors from inserting tabs into my Python source?.
                                                             (line    6)
* PYTHON_BASIC_REPL:                     A better interactive interpreter.
                                                             (line   27)
* PYTHON_BASIC_REPL <1>:                 Library<17>.        (line  322)
* PYTHON_BASIC_REPL <2>:                 Library<17>.        (line  325)
* PYTHON_BASIC_REPL <3>:                 Core and Builtins<23>.
                                                             (line   12)
* PYTHON_BASIC_REPL <4>:                 Interactive Mode<2>.
                                                             (line   23)
* PYTHON_BASIC_REPL <5>:                 Example.            (line   79)
* PYTHON_BASIC_REPL <6>:                 asyncio — Asynchronous I/O.
                                                             (line   81)
* python_branch() (in module platform):  Cross platform.     (line   88)
* python_build() (in module platform):   Cross platform.     (line   78)
* PYTHON_COLORS:                         Summary – Release Highlights.
                                                             (line   57)
* PYTHON_COLORS <1>:                     Improved error messages.
                                                             (line    8)
* PYTHON_COLORS <2>:                     doctest.            (line    7)
* PYTHON_COLORS <3>:                     Controlling color.  (line   22)
* python_compiler() (in module platform): Cross platform.    (line   83)
* PYTHON_CPU_COUNT:                      os.                 (line   11)
* PYTHON_CPU_COUNT <1>:                  Miscellaneous options.
                                                             (line  376)
* PYTHON_CPU_COUNT <2>:                  Miscellaneous System Information.
                                                             (line   48)
* PYTHON_CPU_COUNT <3>:                  Miscellaneous System Information.
                                                             (line   69)
* PYTHON_CPU_COUNT <4>:                  Miscellaneous<3>.   (line   31)
* PYTHON_CPU_COUNT <5>:                  PyConfig.           (line  493)
* PYTHON_DOM:                            Module Contents<3>. (line   23)
* PYTHON_FROZEN_MODULES:                 Other Language Changes.
                                                             (line   46)
* PYTHON_FROZEN_MODULES <1>:             Core and Builtins<34>.
                                                             (line  105)
* PYTHON_FROZEN_MODULES <2>:             Miscellaneous options.
                                                             (line  347)
* PYTHON_GIL:                            Free-threaded CPython.
                                                             (line   22)
* PYTHON_GIL <1>:                        Free-threaded CPython.
                                                             (line   38)
* PYTHON_GIL <2>:                        Core and Builtins<19>.
                                                             (line   36)
* PYTHON_GIL <3>:                        Miscellaneous options.
                                                             (line  394)
* PYTHON_GIL <4>:                        The global interpreter lock in free-threaded Python.
                                                             (line    7)
* PYTHON_GIL <5>:                        Glossary.           (line  745)
* PYTHON_HISTORY:                        Other Language Changes.
                                                             (line   57)
* PYTHON_HISTORY <1>:                    Library<37>.        (line  544)
* python_implementation() (in module platform): Cross platform.
                                                             (line   92)
* python_is_optimized() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  255)
* PYTHON_JIT:                            An experimental just-in-time JIT compiler.
                                                             (line   21)
* PYTHON_JIT <1>:                        An experimental just-in-time JIT compiler.
                                                             (line   24)
* PYTHON_JIT <2>:                        An experimental just-in-time JIT compiler.
                                                             (line   28)
* PYTHON_PERF_JIT_SUPPORT:               Other Language Changes.
                                                             (line   52)
* PYTHON_PERF_JIT_SUPPORT <1>:           Miscellaneous options.
                                                             (line  366)
* PYTHON_PERF_JIT_SUPPORT <2>:           PyConfig.           (line  869)
* PYTHON_PERF_JIT_SUPPORT <3>:           PyConfig.           (line  872)
* PYTHON_PERF_JIT_SUPPORT <4>:           How to work without frame pointers.
                                                             (line   14)
* PYTHON_PRESITE:                        Miscellaneous options.
                                                             (line  388)
* PYTHON_PRESITE <1>:                    PyConfig.           (line  770)
* PYTHON_PRESITE=package.module:         Core and Builtins<34>.
                                                             (line  154)
* python_revision() (in module platform): Cross platform.    (line   97)
* python_version_tuple() (in module platform): Cross platform.
                                                             (line  109)
* python_version() (in module platform): Cross platform.     (line  102)
* python-m-py_compile command line option; -: Command-Line Interface<5>.
                                                             (line   13)
* python-m-py_compile command line option; -q: Command-Line Interface<5>.
                                                             (line   19)
* python-m-py_compile command line option; -quiet: Command-Line Interface<5>.
                                                             (line   19)
* python-m-py_compile command line option; <file>: Command-Line Interface<5>.
                                                             (line   13)
* python-m-sqlite3-[-h]-[-v]-[filename]-[sql] command line option; -h: Command-line interface.
                                                             (line   14)
* python-m-sqlite3-[-h]-[-v]-[filename]-[sql] command line option; -help: Command-line interface.
                                                             (line   14)
* python-m-sqlite3-[-h]-[-v]-[filename]-[sql] command line option; -v: Command-line interface.
                                                             (line   18)
* python-m-sqlite3-[-h]-[-v]-[filename]-[sql] command line option; -version: Command-line interface.
                                                             (line   18)
* PYTHONASYNCIODEBUG:                    Enabling debug mode.
                                                             (line   10)
* PYTHONASYNCIODEBUG <1>:                Debug Mode.         (line   11)
* PYTHONASYNCIODEBUG <2>:                Effects of the Python Development Mode.
                                                             (line   65)
* PYTHONBREAKPOINT:                      PEP 553 Built-in breakpoint.
                                                             (line   13)
* PYTHONBREAKPOINT <1>:                  Built-in Functions. (line  161)
* PYTHONBREAKPOINT <2>:                  sys — System-specific parameters and functions.
                                                             (line  256)
* PYTHONBREAKPOINT <3>:                  sys — System-specific parameters and functions.
                                                             (line  270)
* PYTHONBREAKPOINT <4>:                  sys — System-specific parameters and functions.
                                                             (line  274)
* PYTHONCASEOK:                          Changes in the Python API<4>.
                                                             (line   29)
* PYTHONCASEOK <1>:                      PEP 235 Importing Modules on Case-Insensitive Platforms.
                                                             (line   17)
* PYTHONCASEOK <2>:                      Library<129>.       (line  144)
* PYTHONCASEOK <3>:                      Built-in Functions. (line 2238)
* PYTHONCOERCECLOCALE:                   PEP 538 Legacy C Locale Coercion.
                                                             (line   13)
* PYTHONCOERCECLOCALE <1>:               General Options.    (line   88)
* PYTHONCOERCECLOCALE <2>:               Python UTF-8 Mode.  (line   56)
* PYTHONCOERCECLOCALE <3>:               Python Configuration.
                                                             (line   15)
* PYTHONDEBUG:                           Miscellaneous options.
                                                             (line   37)
* PYTHONDEBUG <1>:                       Python Debug Build. (line   20)
* PYTHONDEBUG <2>:                       Global configuration variables.
                                                             (line   38)
* PYTHONDEBUG <3>:                       PyConfig.           (line  661)
* PYTHONDEVMODE:                         Python Development Mode -X dev.
                                                             (line    6)
* PYTHONDEVMODE <1>:                     Miscellaneous options.
                                                             (line  306)
* PYTHONDEVMODE <2>:                     Python Development Mode.
                                                             (line   14)
* PYTHONDEVMODE <3>:                     PyConfig.           (line  292)
* PYTHONDONTWRITEBYTECODE:               Interpreter Changes<2>.
                                                             (line   16)
* PYTHONDONTWRITEBYTECODE <1>:           New and Improved Modules<2>.
                                                             (line  626)
* PYTHONDONTWRITEBYTECODE <2>:           Miscellaneous options.
                                                             (line   19)
* PYTHONDONTWRITEBYTECODE <3>:           sys — System-specific parameters and functions.
                                                             (line  340)
* PYTHONDONTWRITEBYTECODE <4>:           Global configuration variables.
                                                             (line   52)
* PYTHONDONTWRITEBYTECODE <5>:           PyConfig.           (line  946)
* PYTHONDONTWRITEBYTECODE <6>:           How do I create a pyc file?.
                                                             (line   21)
* PYTHONDUMPREFS:                        Debug build uses the same ABI as release build.
                                                             (line   15)
* PYTHONDUMPREFS <1>:                    Build<58>.          (line   54)
* PYTHONDUMPREFS <2>:                    Debug options.      (line   22)
* PYTHONDUMPREFS <3>:                    Debug options.      (line   24)
* PYTHONDUMPREFS <4>:                    PyConfig.           (line  303)
* PYTHONDUMPREFSFILE:                    Core and Builtins<86>.
                                                             (line   16)
* PYTHONEXECUTABLE:                      PyConfig.           (line  696)
* PYTHONFAULTHANDLER:                    faulthandler<4>.    (line   12)
* PYTHONFAULTHANDLER <1>:                Miscellaneous options.
                                                             (line  268)
* PYTHONFAULTHANDLER <2>:                Effects of the Python Development Mode.
                                                             (line   59)
* PYTHONFAULTHANDLER <3>:                faulthandler — Dump the Python traceback.
                                                             (line   15)
* PYTHONFAULTHANDLER <4>:                PyConfig.           (line  341)
* PythonFinalizationError:               Concrete exceptions.
                                                             (line  225)
* PYTHONHASHSEED:                        Builtin functions and types.
                                                             (line   17)
* PYTHONHASHSEED <1>:                    Porting Python code.
                                                             (line    6)
* PYTHONHASHSEED <2>:                    Core and Builtins<143>.
                                                             (line   30)
* PYTHONHASHSEED <3>:                    Miscellaneous options.
                                                             (line  130)
* PYTHONHASHSEED <4>:                    Miscellaneous options.
                                                             (line  147)
* PYTHONHASHSEED <5>:                    Environment variables.
                                                             (line  155)
* PYTHONHASHSEED <6>:                    Basic customization.
                                                             (line  311)
* PYTHONHASHSEED <7>:                    Global configuration variables.
                                                             (line   77)
* PYTHONHASHSEED <8>:                    Global configuration variables.
                                                             (line   80)
* PYTHONHASHSEED <9>:                    PyConfig.           (line  411)
* PYTHONHOME:                            Deprecated C APIs.  (line   26)
* PYTHONHOME <1>:                        Pending Removal in Python 3 15<2>.
                                                             (line   36)
* PYTHONHOME <2>:                        Pending Removal in Python 3 15<4>.
                                                             (line   36)
* PYTHONHOME <3>:                        Summary – Release highlights<6>.
                                                             (line  107)
* PYTHONHOME <4>:                        Miscellaneous options.
                                                             (line   46)
* PYTHONHOME <5>:                        Environment variables.
                                                             (line   19)
* PYTHONHOME <6>:                        Environment variables.
                                                             (line   21)
* PYTHONHOME <7>:                        Environment variables.
                                                             (line   37)
* PYTHONHOME <8>:                        Finding modules.    (line   29)
* PYTHONHOME <9>:                        Finding modules.    (line   47)
* PYTHONHOME <10>:                       Finding modules.    (line   81)
* PYTHONHOME <11>:                       Adding Python to an iOS project.
                                                             (line  149)
* PYTHONHOME <12>:                       test support script_helper — Utilities for the Python execution tests.
                                                             (line   25)
* PYTHONHOME <13>:                       The initialization of the sys path module search path.
                                                             (line   30)
* PYTHONHOME <14>:                       Virtual environments<2>.
                                                             (line   14)
* PYTHONHOME <15>:                       Embedding Python<2>.
                                                             (line   38)
* PYTHONHOME <16>:                       Embedding Python<2>.
                                                             (line   44)
* PYTHONHOME <17>:                       Global configuration variables.
                                                             (line   92)
* PYTHONHOME <18>:                       Process-wide parameters.
                                                             (line  295)
* PYTHONHOME <19>:                       Process-wide parameters.
                                                             (line  311)
* PYTHONHOME <20>:                       Process-wide parameters.
                                                             (line  320)
* PYTHONHOME <21>:                       PyConfig.           (line  419)
* PYTHONHOME <22>:                       PyConfig.           (line  421)
* PYTHONHOME <23>:                       Pending Removal in Python 3 15<6>.
                                                             (line   36)
* Pythonic:                              Glossary.           (line 1402)
* PYTHONINSPECT:                         Other Changes and Fixes<2>.
                                                             (line   13)
* PYTHONINSPECT <1>:                     Core and Builtins<2>.
                                                             (line   47)
* PYTHONINSPECT <2>:                     Miscellaneous options.
                                                             (line   68)
* PYTHONINSPECT <3>:                     Global configuration variables.
                                                             (line  109)
* PYTHONINSPECT <4>:                     PyConfig.           (line  446)
* PYTHONINTMAXSTRDIGITS:                 Core and Builtins<52>.
                                                             (line   74)
* PYTHONINTMAXSTRDIGITS <1>:             Miscellaneous options.
                                                             (line  290)
* PYTHONINTMAXSTRDIGITS <2>:             Configuring the limit.
                                                             (line    9)
* PYTHONINTMAXSTRDIGITS <3>:             Configuring the limit.
                                                             (line   16)
* PYTHONINTMAXSTRDIGITS <4>:             sys — System-specific parameters and functions.
                                                             (line 1164)
* PYTHONINTMAXSTRDIGITS <5>:             PyConfig.           (line  477)
* PYTHONIOENCODING:                      Other Improvements<2>.
                                                             (line   75)
* PYTHONIOENCODING <1>:                  Interpreter Changes<2>.
                                                             (line   23)
* PYTHONIOENCODING <2>:                  Environment variables.
                                                             (line  401)
* PYTHONIOENCODING <3>:                  Python UTF-8 Mode.  (line   28)
* PYTHONIOENCODING <4>:                  sys — System-specific parameters and functions.
                                                             (line 1848)
* PYTHONIOENCODING <5>:                  PyConfig.           (line  829)
* PYTHONLEGACYWINDOWSFSENCODING:         New Deprecations.   (line  131)
* PYTHONLEGACYWINDOWSFSENCODING <1>:     Pending removal in Python 3 16.
                                                             (line   50)
* PYTHONLEGACYWINDOWSFSENCODING <2>:     Pending removal in Python 3 16<3>.
                                                             (line   50)
* PYTHONLEGACYWINDOWSFSENCODING <3>:     PEP 529 Change Windows filesystem encoding to UTF-8.
                                                             (line   18)
* PYTHONLEGACYWINDOWSFSENCODING <4>:     Windows<17>.        (line   37)
* PYTHONLEGACYWINDOWSFSENCODING <5>:     sys — System-specific parameters and functions.
                                                             (line 1788)
* PYTHONLEGACYWINDOWSFSENCODING <6>:     sys — System-specific parameters and functions.
                                                             (line 1799)
* PYTHONLEGACYWINDOWSFSENCODING <7>:     sys — System-specific parameters and functions.
                                                             (line 1805)
* PYTHONLEGACYWINDOWSFSENCODING <8>:     Global configuration variables.
                                                             (line  151)
* PYTHONLEGACYWINDOWSFSENCODING <9>:     PyPreConfig.        (line  123)
* PYTHONLEGACYWINDOWSFSENCODING <10>:    Pending removal in Python 3 16<5>.
                                                             (line   50)
* PYTHONLEGACYWINDOWSSTDIO:              PEP 528 Change Windows console encoding to UTF-8.
                                                             (line   12)
* PYTHONLEGACYWINDOWSSTDIO <1>:          Environment variables.
                                                             (line  190)
* PYTHONLEGACYWINDOWSSTDIO <2>:          sys — System-specific parameters and functions.
                                                             (line 1852)
* PYTHONLEGACYWINDOWSSTDIO <3>:          Global configuration variables.
                                                             (line  169)
* PYTHONLEGACYWINDOWSSTDIO <4>:          PyConfig.           (line  530)
* PYTHONMALLOC:                          PYTHONMALLOC environment variable.
                                                             (line    6)
* PYTHONMALLOC <1>:                      Changes in the C API<6>.
                                                             (line    9)
* PYTHONMALLOC <2>:                      Core and Builtins<163>.
                                                             (line   90)
* PYTHONMALLOC <3>:                      Environment variables.
                                                             (line  328)
* PYTHONMALLOC <4>:                      Performance options.
                                                             (line  109)
* PYTHONMALLOC <5>:                      Performance options.
                                                             (line  116)
* PYTHONMALLOC <6>:                      Effects of the Python Development Mode.
                                                             (line   46)
* PYTHONMALLOC <7>:                      Effects of the Python Development Mode.
                                                             (line   50)
* PYTHONMALLOC <8>:                      Overview<4>.        (line   75)
* PYTHONMALLOC <9>:                      Default Memory Allocators.
                                                             (line   26)
* PYTHONMALLOC <10>:                     Debug hooks on the Python memory allocators.
                                                             (line   11)
* PYTHONMALLOC <11>:                     The pymalloc allocator.
                                                             (line   27)
* PYTHONMALLOCSTATS:                     Core and Builtins<163>.
                                                             (line   96)
* PYTHONMALLOCSTATS <1>:                 PyConfig.           (line  546)
* PYTHONMALLOCSTATS <2>:                 Overview<4>.        (line   78)
* PYTHONNODEBUGRANGES:                   PEP 657 Fine-grained error locations in tracebacks.
                                                             (line   63)
* PYTHONNODEBUGRANGES <1>:               Miscellaneous options.
                                                             (line  335)
* PYTHONNODEBUGRANGES <2>:               Methods on code objects.
                                                             (line   40)
* PYTHONNODEBUGRANGES <3>:               PyConfig.           (line  245)
* PYTHONNOUSERSITE:                      PEP 370 Per-user site-packages Directory.
                                                             (line   30)
* PYTHONNOUSERSITE <1>:                  Miscellaneous options.
                                                             (line  159)
* PYTHONNOUSERSITE <2>:                  Module contents<6>. (line   15)
* PYTHONNOUSERSITE <3>:                  Global configuration variables.
                                                             (line  203)
* PYTHONNOUSERSITE <4>:                  PyConfig.           (line  899)
* PYTHONOPTIMIZE:                        Miscellaneous options.
                                                             (line   88)
* PYTHONOPTIMIZE <1>:                    Global configuration variables.
                                                             (line  214)
* PYTHONOPTIMIZE <2>:                    PyConfig.           (line  613)
* PYTHONPATH:                            Changes in ‘python’ Command Behavior<2>.
                                                             (line    8)
* PYTHONPATH <1>:                        Changes in ‘python’ Command Behavior<2>.
                                                             (line    9)
* PYTHONPATH <2>:                        The Module Search Path.
                                                             (line   16)
* PYTHONPATH <3>:                        Standard Modules.   (line   34)
* PYTHONPATH <4>:                        Standard Modules.   (line   35)
* PYTHONPATH <5>:                        Miscellaneous options.
                                                             (line   45)
* PYTHONPATH <6>:                        Environment variables.
                                                             (line   31)
* PYTHONPATH <7>:                        Environment variables.
                                                             (line   38)
* PYTHONPATH <8>:                        Environment variables.
                                                             (line   41)
* PYTHONPATH <9>:                        Excursus Setting environment variables.
                                                             (line   38)
* PYTHONPATH <10>:                       Finding modules.    (line   15)
* PYTHONPATH <11>:                       Finding modules.    (line   38)
* PYTHONPATH <12>:                       Finding modules.    (line   81)
* PYTHONPATH <13>:                       Adding Python to an iOS project.
                                                             (line  152)
* PYTHONPATH <14>:                       Adding Python to an iOS project.
                                                             (line  183)
* PYTHONPATH <15>:                       Adding Python to an iOS project.
                                                             (line  189)
* PYTHONPATH <16>:                       Path entry finders. (line    6)
* PYTHONPATH <17>:                       Path entry finders. (line   23)
* PYTHONPATH <18>:                       test support script_helper — Utilities for the Python execution tests.
                                                             (line   26)
* PYTHONPATH <19>:                       sys — System-specific parameters and functions.
                                                             (line 1330)
* PYTHONPATH <20>:                       sys — System-specific parameters and functions.
                                                             (line 1335)
* PYTHONPATH <21>:                       The initialization of the sys path module search path.
                                                             (line   14)
* PYTHONPATH <22>:                       The initialization of the sys path module search path.
                                                             (line   18)
* PYTHONPATH <23>:                       Building C and C++ Extensions.
                                                             (line    9)
* PYTHONPATH <24>:                       Embedding Python<2>.
                                                             (line   39)
* PYTHONPATH <25>:                       Embedding Python<2>.
                                                             (line   45)
* PYTHONPATH <26>:                       Global configuration variables.
                                                             (line   91)
* PYTHONPATH <27>:                       PyConfig.           (line  579)
* PYTHONPERFSUPPORT:                     Other Language Changes<2>.
                                                             (line   84)
* PYTHONPERFSUPPORT <1>:                 Miscellaneous options.
                                                             (line  355)
* PYTHONPERFSUPPORT <2>:                 How to enable perf profiling support.
                                                             (line    7)
* PYTHONPLATLIBDIR:                      Core and Builtins<122>.
                                                             (line   47)
* PYTHONPLATLIBDIR <1>:                  The initialization of the sys path module search path.
                                                             (line   51)
* PYTHONPLATLIBDIR <2>:                  PyConfig.           (line  558)
* PYTHONPROFILEIMPORTTIME:               Other Language Changes<7>.
                                                             (line   47)
* PYTHONPROFILEIMPORTTIME <1>:           Core and Builtins<145>.
                                                             (line   66)
* PYTHONPROFILEIMPORTTIME <2>:           Miscellaneous options.
                                                             (line  299)
* PYTHONPROFILEIMPORTTIME <3>:           PyConfig.           (line  431)
* PYTHONPYCACHEPREFIX:                   Parallel filesystem cache for compiled bytecode files.
                                                             (line    6)
* PYTHONPYCACHEPREFIX <1>:               Core and Builtins<136>.
                                                             (line  402)
* PYTHONPYCACHEPREFIX <2>:               Miscellaneous options.
                                                             (line  319)
* PYTHONPYCACHEPREFIX <3>:               sys — System-specific parameters and functions.
                                                             (line  386)
* PYTHONPYCACHEPREFIX <4>:               PyConfig.           (line  718)
* PYTHONREGRTEST_UNICODE_GUARD:          Tests<30>.          (line   13)
* PYTHONSAFEPATH:                        Summary – Release highlights<2>.
                                                             (line   27)
* PYTHONSAFEPATH <1>:                    Other Language Changes<3>.
                                                             (line   37)
* PYTHONSAFEPATH <2>:                    Security<25>.       (line    6)
* PYTHONSAFEPATH <3>:                    Miscellaneous options.
                                                             (line  116)
* PYTHONSAFEPATH <4>:                    sys — System-specific parameters and functions.
                                                             (line 1347)
* PYTHONSAFEPATH <5>:                    Security Considerations<3>.
                                                             (line   47)
* PYTHONSAFEPATH <6>:                    PyConfig.           (line  162)
* PYTHONSTARTUP:                         sys<12>.            (line   17)
* PYTHONSTARTUP <1>:                     sys<12>.            (line   21)
* PYTHONSTARTUP <2>:                     Library<2>.         (line  116)
* PYTHONSTARTUP <3>:                     Core and Builtins<5>.
                                                             (line   24)
* PYTHONSTARTUP <4>:                     IDLE<41>.           (line  176)
* PYTHONSTARTUP <5>:                     IDLE<45>.           (line    9)
* PYTHONSTARTUP <6>:                     IDLE<51>.           (line    9)
* PYTHONSTARTUP <7>:                     The Interactive Startup File.
                                                             (line    8)
* PYTHONSTARTUP <8>:                     Miscellaneous options.
                                                             (line   64)
* PYTHONSTARTUP <9>:                     Environment variables.
                                                             (line  116)
* PYTHONSTARTUP <10>:                    Example.            (line   10)
* PYTHONSTARTUP <11>:                    asyncio — Asynchronous I/O.
                                                             (line   91)
* PYTHONSTARTUP <12>:                    Startup and Code Execution.
                                                             (line    7)
* PYTHONSTARTUP <13>:                    Command-line usage<3>.
                                                             (line   42)
* PYTHONSTARTUP <14>:                    sys — System-specific parameters and functions.
                                                             (line 1177)
* PYTHONSTARTUP <15>:                    Readline configuration.
                                                             (line   12)
* PYTHONTRACEMALLOC:                     Miscellaneous options.
                                                             (line  285)
* PYTHONTRACEMALLOC <1>:                 tracemalloc — Trace memory allocations.
                                                             (line   25)
* PYTHONTRACEMALLOC <2>:                 tracemalloc — Trace memory allocations.
                                                             (line   32)
* PYTHONTRACEMALLOC <3>:                 Functions<11>.      (line   89)
* PYTHONTRACEMALLOC <4>:                 PyConfig.           (line  857)
* PYTHONTZPATH:                          Exceptions and warnings.
                                                             (line   14)
* PYTHONUNBUFFERED:                      Core and Builtins<129>.
                                                             (line  107)
* PYTHONUNBUFFERED <1>:                  Miscellaneous options.
                                                             (line  179)
* PYTHONUNBUFFERED <2>:                  sys — System-specific parameters and functions.
                                                             (line 1859)
* PYTHONUNBUFFERED <3>:                  Global configuration variables.
                                                             (line  242)
* PYTHONUNBUFFERED <4>:                  PyConfig.           (line  209)
* PYTHONUOPS:                            Core and Builtins<35>.
                                                             (line   27)
* PYTHONUOPS <1>:                        Core and Builtins<35>.
                                                             (line  179)
* PYTHONUOPS <2>:                        Core and Builtins<35>.
                                                             (line  258)
* PYTHONUOPS <3>:                        Core and Builtins<35>.
                                                             (line  317)
* PYTHONUOPS <4>:                        Core and Builtins<35>.
                                                             (line  381)
* PYTHONUSERBASE:                        PEP 370 Per-user site-packages Directory.
                                                             (line   23)
* PYTHONUSERBASE <1>:                    Module contents<6>. (line   40)
* PYTHONUSERBASE <2>:                    Module contents<6>. (line   68)
* PYTHONUSERSITE:                        test support script_helper — Utilities for the Python execution tests.
                                                             (line   26)
* PYTHONUTF8:                            PEP 540 Forced UTF-8 Runtime Mode.
                                                             (line    6)
* PYTHONUTF8 <1>:                        Miscellaneous options.
                                                             (line  313)
* PYTHONUTF8 <2>:                        Environment variables.
                                                             (line  411)
* PYTHONUTF8 <3>:                        UTF-8 mode.         (line   18)
* PYTHONUTF8 <4>:                        Python UTF-8 Mode.  (line   51)
* PYTHONUTF8 <5>:                        Python UTF-8 Mode.  (line   53)
* PYTHONUTF8 <6>:                        sys — System-specific parameters and functions.
                                                             (line 1850)
* PYTHONUTF8 <7>:                        PyPreConfig.        (line  152)
* PYTHONUTF8 <8>:                        Python Configuration.
                                                             (line   14)
* PYTHONVERBOSE:                         Miscellaneous options.
                                                             (line  195)
* PYTHONVERBOSE <1>:                     Global configuration variables.
                                                             (line  259)
* PYTHONVERBOSE <2>:                     PyConfig.           (line  916)
* PYTHONWARNDEFAULTENCODING:             Optional EncodingWarning and encoding="locale" option.
                                                             (line   19)
* PYTHONWARNDEFAULTENCODING <1>:         Library<97>.        (line   45)
* PYTHONWARNDEFAULTENCODING <2>:         Miscellaneous options.
                                                             (line  325)
* PYTHONWARNDEFAULTENCODING <3>:         Opt-in EncodingWarning.
                                                             (line    9)
* PYTHONWARNINGS:                        warnings<3>.        (line   21)
* PYTHONWARNINGS <1>:                    Other Language Changes<12>.
                                                             (line  159)
* PYTHONWARNINGS <2>:                    Changes to the Handling of Deprecation Warnings.
                                                             (line   25)
* PYTHONWARNINGS <3>:                    Interpreter Changes.
                                                             (line    6)
* PYTHONWARNINGS <4>:                    Documentation<26>.  (line   67)
* PYTHONWARNINGS <5>:                    Miscellaneous options.
                                                             (line  249)
* PYTHONWARNINGS <6>:                    Effects of the Python Development Mode.
                                                             (line   30)
* PYTHONWARNINGS <7>:                    The Warnings Filter.
                                                             (line   46)
* PYTHONWARNINGS <8>:                    The Warnings Filter.
                                                             (line   56)
* PYTHONWARNINGS <9>:                    Describing Warning Filters.
                                                             (line    7)
* PYTHONWARNINGS <10>:                   Describing Warning Filters.
                                                             (line   21)
* PYTHONWARNINGS <11>:                   Default Warning Filter.
                                                             (line    7)
* PYTHONWARNINGS <12>:                   PyConfig.           (line  935)
* PyThread_acquire_lock (C function):    Legacy Locking APIs.
                                                             (line   73)
* PyThread_acquire_lock_timed (C function): Legacy Locking APIs.
                                                             (line   51)
* PyThread_allocate_lock (C function):   Legacy Locking APIs.
                                                             (line   32)
* PyThread_create_key (C function):      Thread Local Storage TLS API.
                                                             (line   18)
* PyThread_delete_key (C function):      Thread Local Storage TLS API.
                                                             (line   21)
* PyThread_delete_key_value (C function): Thread Local Storage TLS API.
                                                             (line   30)
* PyThread_exit_thread (C function):     Operating System Thread APIs.
                                                             (line   70)
* PyThread_free_lock (C function):       Legacy Locking APIs.
                                                             (line   45)
* PyThread_get_key_value (C function):   Thread Local Storage TLS API.
                                                             (line   27)
* PyThread_get_stacksize (C function):   Operating System Thread APIs.
                                                             (line  106)
* PyThread_get_thread_ident (C function): Operating System Thread APIs.
                                                             (line   25)
* PyThread_get_thread_native_id (C function): Operating System Thread APIs.
                                                             (line   53)
* PyThread_GetInfo (C function):         Operating System Thread APIs.
                                                             (line   37)
* PyThread_init_thread (C function):     Operating System Thread APIs.
                                                             (line   91)
* PYTHREAD_INVALID_THREAD_ID (C macro):  Operating System Thread APIs.
                                                             (line    6)
* PyThread_ReInitTLS (C function):       Thread Local Storage TLS API.
                                                             (line   33)
* PyThread_release_lock (C function):    Legacy Locking APIs.
                                                             (line   91)
* PyThread_set_key_value (C function):   Thread Local Storage TLS API.
                                                             (line   24)
* PyThread_set_stacksize (C function):   Operating System Thread APIs.
                                                             (line   96)
* PyThread_start_new_thread (C function): Operating System Thread APIs.
                                                             (line   12)
* PyThread_tss_alloc (C function):       Dynamic Allocation. (line   11)
* PyThread_tss_create (C function):      Methods<2>.         (line   16)
* PyThread_tss_delete (C function):      Methods<2>.         (line   24)
* PyThread_tss_free (C function):        Dynamic Allocation. (line   17)
* PyThread_tss_get (C function):         Methods<2>.         (line   39)
* PyThread_tss_is_created (C function):  Methods<2>.         (line   11)
* PyThread_tss_set (C function):         Methods<2>.         (line   33)
* PyThread_type_lock (C type):           Legacy Locking APIs.
                                                             (line   12)
* PyThreadState (C type):                Thread State and the Global Interpreter Lock.
                                                             (line   23)
* PyThreadState (C type) <1>:            High-level API.     (line   25)
* PyThreadState_Clear (C function):      Low-level API.      (line   44)
* PyThreadState_Delete (C function):     Low-level API.      (line   55)
* PyThreadState_DeleteCurrent (C function): Low-level API.   (line   61)
* PyThreadState_EnterTracing (C function): Low-level API.    (line   99)
* PyThreadState_Get (C function):        High-level API.     (line   76)
* PyThreadState_GetDict (C function):    Low-level API.      (line  203)
* PyThreadState_GetFrame (C function):   Low-level API.      (line   68)
* PyThreadState_GetID (C function):      Low-level API.      (line   82)
* PyThreadState_GetInterpreter (C function): Low-level API.  (line   90)
* PyThreadState_GetUnchecked (C function): High-level API.   (line   84)
* PyThreadState_LeaveTracing (C function): Low-level API.    (line  108)
* PyThreadState_New (C function):        Low-level API.      (line   37)
* PyThreadState_Next (C function):       Advanced Debugger Support.
                                                             (line   32)
* PyThreadState_SetAsyncExc (C function): Low-level API.     (line  212)
* PyThreadState_Swap (C function):       High-level API.     (line   93)
* PyThreadState.interp (C member):       High-level API.     (line   30)
* PyTime_AsSecondsDouble (C function):   Conversion functions.
                                                             (line    6)
* PyTime_Check (C function):             DateTime Objects<2>.
                                                             (line  126)
* PyTime_CheckExact (C function):        DateTime Objects<2>.
                                                             (line  132)
* PyTime_FromTime (C function):          DateTime Objects<2>.
                                                             (line  182)
* PyTime_FromTimeAndFold (C function):   DateTime Objects<2>.
                                                             (line  187)
* PyTime_MAX (C var):                    Types<2>.           (line   24)
* PyTime_MIN (C var):                    Types<2>.           (line   20)
* PyTime_Monotonic (C function):         Clock Functions.    (line   21)
* PyTime_MonotonicRaw (C function):      Raw Clock Functions.
                                                             (line   16)
* PyTime_PerfCounter (C function):       Clock Functions.    (line   26)
* PyTime_PerfCounterRaw (C function):    Raw Clock Functions.
                                                             (line   21)
* PyTime_t (C type):                     Types<2>.           (line    6)
* PyTime_Time (C function):              Clock Functions.    (line   31)
* PyTime_TimeRaw (C function):           Raw Clock Functions.
                                                             (line   26)
* PyTimeZone_FromOffset (C function):    DateTime Objects<2>.
                                                             (line  203)
* PyTimeZone_FromOffsetAndName (C function): DateTime Objects<2>.
                                                             (line  211)
* PyTrace_C_CALL (C var):                Profiling and Tracing.
                                                             (line   94)
* PyTrace_C_EXCEPTION (C var):           Profiling and Tracing.
                                                             (line   99)
* PyTrace_C_RETURN (C var):              Profiling and Tracing.
                                                             (line  104)
* PyTrace_CALL (C var):                  Profiling and Tracing.
                                                             (line   62)
* PyTrace_EXCEPTION (C var):             Profiling and Tracing.
                                                             (line   70)
* PyTrace_LINE (C var):                  Profiling and Tracing.
                                                             (line   82)
* PyTrace_OPCODE (C var):                Profiling and Tracing.
                                                             (line  109)
* PyTrace_RETURN (C var):                Profiling and Tracing.
                                                             (line   89)
* PyTraceBack_Check (C function):        Tracebacks.         (line   11)
* PyTraceBack_Here (C function):         Tracebacks.         (line   16)
* PyTraceBack_Print (C function):        Tracebacks.         (line   27)
* PyTraceBack_Type (C var):              Tracebacks.         (line    6)
* PyTraceMalloc_Track (C function):      tracemalloc C API.  (line    8)
* PyTraceMalloc_Untrack (C function):    tracemalloc C API.  (line   20)
* PyTuple_Check (C function):            Tuple Objects.      (line   16)
* PyTuple_CheckExact (C function):       Tuple Objects.      (line   21)
* PyTuple_GET_ITEM (C function):         Tuple Objects.      (line   61)
* PyTuple_GET_SIZE (C function):         Tuple Objects.      (line   44)
* PyTuple_GetItem (C function):          Tuple Objects.      (line   48)
* PyTuple_GetSlice (C function):         Tuple Objects.      (line   66)
* PyTuple_New (C function):              Tuple Objects.      (line   26)
* PyTuple_Pack (C function):             Tuple Objects.      (line   31)
* PyTuple_SET_ITEM (C function):         Tuple Objects.      (line   86)
* PyTuple_SetItem (C function):          Reference Count Details.
                                                             (line   26)
* PyTuple_SetItem (C function) <1>:      Tuple Objects.      (line   75)
* PyTuple_Size (C function):             Tuple Objects.      (line   39)
* PyTuple_Type (C var):                  Tuple Objects.      (line   11)
* PyTupleIter_Type (C var):              Other Iterator Objects.
                                                             (line   21)
* PyTupleObject (C type):                Tuple Objects.      (line    6)
* PyType_AddWatcher (C function):        Type Objects<2>.    (line   67)
* PyType_Check (C function):             Type Objects<2>.    (line   15)
* PyType_CheckExact (C function):        Type Objects<2>.    (line   21)
* PyType_ClearCache (C function):        Type Objects<2>.    (line   27)
* PyType_ClearWatcher (C function):      Type Objects<2>.    (line   80)
* PyType_FastSubclass (C function):      Type Objects<2>.    (line  138)
* PyType_FromMetaclass (C function):     Creating Heap-Allocated Types.
                                                             (line    9)
* PyType_FromModuleAndSpec (C function): Creating Heap-Allocated Types.
                                                             (line   59)
* PyType_FromSpec (C function):          Creating Heap-Allocated Types.
                                                             (line   96)
* PyType_FromSpecWithBases (C function): Creating Heap-Allocated Types.
                                                             (line   79)
* PyType_GenericAlloc (C function):      Type Objects<2>.    (line  166)
* PyType_GenericNew (C function):        Type Objects<2>.    (line  173)
* PyType_GetDict (C function):           Type Objects<2>.    (line   43)
* PyType_GetFlags (C function):          Type Objects<2>.    (line   31)
* PyType_GetFullyQualifiedName (C function): Type Objects<2>.
                                                             (line  212)
* PyType_GetModule (C function):         Type Objects<2>.    (line  247)
* PyType_GetModuleByDef (C function):    Type Objects<2>.    (line  286)
* PyType_GetModuleName (C function):     Type Objects<2>.    (line  222)
* PyType_GetModuleState (C function):    Type Objects<2>.    (line  272)
* PyType_GetName (C function):           Type Objects<2>.    (line  196)
* PyType_GetQualName (C function):       Type Objects<2>.    (line  204)
* PyType_GetSlot (C function):           Type Objects<2>.    (line  230)
* PyType_GetTypeDataSize (C function):   Object Protocol.    (line  567)
* PyType_HasFeature (C function):        Type Objects<2>.    (line  133)
* PyType_IS_GC (C function):             Type Objects<2>.    (line  152)
* PyType_IsSubtype (C function):         Type Objects<2>.    (line  157)
* PyType_Modified (C function):          Type Objects<2>.    (line   61)
* PyType_Ready (C function):             Type Objects<2>.    (line  180)
* PyType_Slot (C type):                  Creating Heap-Allocated Types.
                                                             (line  179)
* PyType_Slot.pfunc (C member):          Creating Heap-Allocated Types.
                                                             (line  241)
* PyType_Slot.slot (C member):           Creating Heap-Allocated Types.
                                                             (line  184)
* PyType_Spec (C type):                  Creating Heap-Allocated Types.
                                                             (line  112)
* PyType_Spec.basicsize (C member):      Creating Heap-Allocated Types.
                                                             (line  121)
* PyType_Spec.flags (C member):          Creating Heap-Allocated Types.
                                                             (line  165)
* PyType_Spec.itemsize (C member):       Creating Heap-Allocated Types.
                                                             (line  139)
* PyType_Spec.name (C member):           Creating Heap-Allocated Types.
                                                             (line  116)
* PyType_Spec.slots (C member):          Creating Heap-Allocated Types.
                                                             (line  172)
* PyType_SUPPORTS_WEAKREFS (C function): Type Objects<2>.    (line  319)
* PyType_Type (C var):                   Type Objects<2>.    (line   10)
* PyType_Unwatch (C function):           Type Objects<2>.    (line  108)
* PyType_Watch (C function):             Type Objects<2>.    (line   92)
* PyType_WatchCallback (C type):         Type Objects<2>.    (line  122)
* PyTypeObject (C type):                 Type Objects<2>.    (line    6)
* PyTypeObject.tp_alloc (C member):      PyTypeObject Slots. (line 1527)
* PyTypeObject.tp_as_async (C member):   PyTypeObject Slots. (line  287)
* PyTypeObject.tp_as_buffer (C member):  PyTypeObject Slots. (line  518)
* PyTypeObject.tp_as_mapping (C member): PyTypeObject Slots. (line  356)
* PyTypeObject.tp_as_number (C member):  PyTypeObject Slots. (line  332)
* PyTypeObject.tp_as_sequence (C member): PyTypeObject Slots.
                                                             (line  344)
* PyTypeObject.tp_base (C member):       PyTypeObject Slots. (line 1339)
* PyTypeObject.tp_bases (C member):      PyTypeObject Slots. (line 1654)
* PyTypeObject.tp_basicsize (C member):  PyTypeObject Slots. (line   48)
* PyTypeObject.tp_cache (C member):      PyTypeObject Slots. (line 1691)
* PyTypeObject.tp_call (C member):       PyTypeObject Slots. (line  412)
* PyTypeObject.tp_clear (C member):      PyTypeObject Slots. (line 1039)
* PyTypeObject.tp_dealloc (C member):    PyTypeObject Slots. (line  133)
* PyTypeObject.tp_del (C member):        PyTypeObject Slots. (line 1730)
* PyTypeObject.tp_descr_get (C member):  PyTypeObject Slots. (line 1410)
* PyTypeObject.tp_descr_set (C member):  PyTypeObject Slots. (line 1426)
* PyTypeObject.tp_dict (C member):       PyTypeObject Slots. (line 1374)
* PyTypeObject.tp_dictoffset (C member): PyTypeObject Slots. (line 1445)
* PyTypeObject.tp_doc (C member):        PyTypeObject Slots. (line  926)
* PyTypeObject.tp_finalize (C member):   PyTypeObject Slots. (line 1745)
* PyTypeObject.tp_flags (C member):      PyTypeObject Slots. (line  530)
* PyTypeObject.tp_free (C member):       PyTypeObject Slots. (line 1595)
* PyTypeObject.tp_getattr (C member):    PyTypeObject Slots. (line  242)
* PyTypeObject.tp_getattro (C member):   PyTypeObject Slots. (line  456)
* PyTypeObject.tp_getset (C member):     PyTypeObject Slots. (line 1320)
* PyTypeObject.tp_hash (C member):       PyTypeObject Slots. (line  368)
* PyTypeObject.tp_init (C member):       PyTypeObject Slots. (line 1489)
* PyTypeObject.tp_is_gc (C member):      PyTypeObject Slots. (line 1622)
* PyTypeObject.tp_itemsize (C member):   PyTypeObject Slots. (line   48)
* PyTypeObject.tp_iter (C member):       PyTypeObject Slots. (line 1237)
* PyTypeObject.tp_iternext (C member):   PyTypeObject Slots. (line 1256)
* PyTypeObject.tp_members (C member):    PyTypeObject Slots. (line 1301)
* PyTypeObject.tp_methods (C member):    PyTypeObject Slots. (line 1282)
* PyTypeObject.tp_mro (C member):        PyTypeObject Slots. (line 1677)
* PyTypeObject.tp_name (C member):       PyTypeObject Slots. (line   12)
* PyTypeObject.tp_new (C member):        PyTypeObject Slots. (line 1553)
* PyTypeObject.tp_repr (C member):       PyTypeObject Slots. (line  303)
* PyTypeObject.tp_richcompare (C member): PyTypeObject Slots.
                                                             (line 1122)
* PyTypeObject.tp_setattr (C member):    PyTypeObject Slots. (line  264)
* PyTypeObject.tp_setattro (C member):   PyTypeObject Slots. (line  486)
* PyTypeObject.tp_str (C member):        PyTypeObject Slots. (line  427)
* PyTypeObject.tp_subclasses (C member): PyTypeObject Slots. (line 1699)
* PyTypeObject.tp_traverse (C member):   PyTypeObject Slots. (line  939)
* PyTypeObject.tp_vectorcall (C member): PyTypeObject Slots. (line 1795)
* PyTypeObject.tp_vectorcall_offset (C member): PyTypeObject Slots.
                                                             (line  202)
* PyTypeObject.tp_version_tag (C member): PyTypeObject Slots.
                                                             (line 1737)
* PyTypeObject.tp_watched (C member):    PyTypeObject Slots. (line 1811)
* PyTypeObject.tp_weaklist (C member):   PyTypeObject Slots. (line 1715)
* PyTypeObject.tp_weaklistoffset (C member): PyTypeObject Slots.
                                                             (line 1201)
* PyTZInfo_Check (C function):           DateTime Objects<2>.
                                                             (line  148)
* PyTZInfo_CheckExact (C function):      DateTime Objects<2>.
                                                             (line  154)
* PyUnicode_1BYTE_DATA (C function):     Unicode Type.       (line   82)
* PyUnicode_1BYTE_KIND (C macro):        Unicode Type.       (line   97)
* PyUnicode_2BYTE_DATA (C function):     Unicode Type.       (line   82)
* PyUnicode_2BYTE_KIND (C macro):        Unicode Type.       (line   97)
* PyUnicode_4BYTE_DATA (C function):     Unicode Type.       (line   82)
* PyUnicode_4BYTE_KIND (C macro):        Unicode Type.       (line   97)
* PyUnicode_AsASCIIString (C function):  ASCII Codecs.       (line   16)
* PyUnicode_AsCharmapString (C function): Character Map Codecs.
                                                             (line   31)
* PyUnicode_AsEncodedString (C function): Generic Codecs.    (line   18)
* PyUnicode_AsLatin1String (C function): Latin-1 Codecs.     (line   17)
* PyUnicode_AsMBCSString (C function):   MBCS codecs for Windows.
                                                             (line   37)
* PyUnicode_AsRawUnicodeEscapeString (C function): Raw-Unicode-Escape Codecs.
                                                             (line   15)
* PyUnicode_AsUCS4 (C function):         Creating and accessing Unicode strings.
                                                             (line  388)
* PyUnicode_AsUCS4Copy (C function):     Creating and accessing Unicode strings.
                                                             (line  398)
* PyUnicode_AsUnicodeEscapeString (C function): Unicode-Escape Codecs.
                                                             (line   15)
* PyUnicode_AsUTF16String (C function):  UTF-16 Codecs.      (line   48)
* PyUnicode_AsUTF32String (C function):  UTF-32 Codecs.      (line   47)
* PyUnicode_AsUTF8 (C function):         UTF-8 Codecs.       (line   65)
* PyUnicode_AsUTF8AndSize (C function):  UTF-8 Codecs.       (line   35)
* PyUnicode_AsUTF8String (C function):   UTF-8 Codecs.       (line   25)
* PyUnicode_AsWideChar (C function):     wchar_t Support.    (line   16)
* PyUnicode_AsWideCharString (C function): wchar_t Support.  (line   34)
* PyUnicode_BuildEncodingMap (C function): Creating and accessing Unicode strings.
                                                             (line  297)
* PyUnicode_Check (C function):          Unicode Type.       (line   54)
* PyUnicode_CheckExact (C function):     Unicode Type.       (line   59)
* PyUnicode_Compare (C function):        Methods and Slot Functions.
                                                             (line  132)
* PyUnicode_CompareWithASCIIString (C function): Methods and Slot Functions.
                                                             (line  162)
* PyUnicode_Concat (C function):         Methods and Slot Functions.
                                                             (line   12)
* PyUnicode_Contains (C function):       Methods and Slot Functions.
                                                             (line  196)
* PyUnicode_CopyCharacters (C function): Creating and accessing Unicode strings.
                                                             (line  324)
* PyUnicode_Count (C function):          Methods and Slot Functions.
                                                             (line  118)
* PyUnicode_DATA (C function):           Unicode Type.       (line  116)
* PyUnicode_Decode (C function):         Generic Codecs.     (line    8)
* PyUnicode_DecodeASCII (C function):    ASCII Codecs.       (line    9)
* PyUnicode_DecodeCharmap (C function):  Character Map Codecs.
                                                             (line   15)
* PyUnicode_DecodeCodePageStateful (C function): MBCS codecs for Windows.
                                                             (line   29)
* PyUnicode_DecodeFSDefault (C function): File System Encoding.
                                                             (line   76)
* PyUnicode_DecodeFSDefaultAndSize (C function): File System Encoding.
                                                             (line   59)
* PyUnicode_DecodeLatin1 (C function):   Latin-1 Codecs.     (line   10)
* PyUnicode_DecodeLocale (C function):   Locale Encoding.    (line   37)
* PyUnicode_DecodeLocaleAndSize (C function): Locale Encoding.
                                                             (line    9)
* PyUnicode_DecodeMBCS (C function):     MBCS codecs for Windows.
                                                             (line   12)
* PyUnicode_DecodeMBCSStateful (C function): MBCS codecs for Windows.
                                                             (line   19)
* PyUnicode_DecodeRawUnicodeEscape (C function): Raw-Unicode-Escape Codecs.
                                                             (line    8)
* PyUnicode_DecodeUnicodeEscape (C function): Unicode-Escape Codecs.
                                                             (line    8)
* PyUnicode_DecodeUTF16 (C function):    UTF-16 Codecs.      (line    8)
* PyUnicode_DecodeUTF16Stateful (C function): UTF-16 Codecs. (line   36)
* PyUnicode_DecodeUTF32 (C function):    UTF-32 Codecs.      (line    8)
* PyUnicode_DecodeUTF32Stateful (C function): UTF-32 Codecs. (line   35)
* PyUnicode_DecodeUTF7 (C function):     UTF-7 Codecs.       (line    8)
* PyUnicode_DecodeUTF7Stateful (C function): UTF-7 Codecs.   (line   15)
* PyUnicode_DecodeUTF8 (C function):     UTF-8 Codecs.       (line    8)
* PyUnicode_DecodeUTF8Stateful (C function): UTF-8 Codecs.   (line   15)
* PyUnicode_EncodeCodePage (C function): MBCS codecs for Windows.
                                                             (line   44)
* PyUnicode_EncodeFSDefault (C function): File System Encoding.
                                                             (line   88)
* PyUnicode_EncodeLocale (C function):   Locale Encoding.    (line   46)
* PyUnicode_EqualToUTF8 (C function):    Methods and Slot Functions.
                                                             (line  153)
* PyUnicode_EqualToUTF8AndSize (C function): Methods and Slot Functions.
                                                             (line  140)
* PyUnicode_Fill (C function):           Creating and accessing Unicode strings.
                                                             (line  335)
* PyUnicode_Find (C function):           Methods and Slot Functions.
                                                             (line   91)
* PyUnicode_FindChar (C function):       Methods and Slot Functions.
                                                             (line  102)
* PyUnicode_Format (C function):         Methods and Slot Functions.
                                                             (line  190)
* PyUnicode_FromEncodedObject (C function): Creating and accessing Unicode strings.
                                                             (line  280)
* PyUnicode_FromFormat (C function):     Creating and accessing Unicode strings.
                                                             (line   62)
* PyUnicode_FromFormatV (C function):    Creating and accessing Unicode strings.
                                                             (line  254)
* PyUnicode_FromKindAndData (C function): Creating and accessing Unicode strings.
                                                             (line   23)
* PyUnicode_FromObject (C function):     Creating and accessing Unicode strings.
                                                             (line  260)
* PyUnicode_FromOrdinal (C function):    Creating and accessing Unicode strings.
                                                             (line  271)
* PyUnicode_FromString (C function):     Creating and accessing Unicode strings.
                                                             (line   56)
* PyUnicode_FromStringAndSize (C function): Creating and accessing Unicode strings.
                                                             (line   39)
* PyUnicode_FromWideChar (C function):   wchar_t Support.    (line    8)
* PyUnicode_FSConverter (C function):    File System Encoding.
                                                             (line   13)
* PyUnicode_FSDecoder (C function):      File System Encoding.
                                                             (line   38)
* PyUnicode_GET_LENGTH (C function):     Unicode Type.       (line   73)
* PyUnicode_GetDefaultEncoding (C function): Creating and accessing Unicode strings.
                                                             (line  307)
* PyUnicode_GetLength (C function):      Creating and accessing Unicode strings.
                                                             (line  315)
* PyUnicode_InternFromString (C function): Methods and Slot Functions.
                                                             (line  230)
* PyUnicode_InternInPlace (C function):  Methods and Slot Functions.
                                                             (line  204)
* PyUnicode_IsIdentifier (C function):   Unicode Type.       (line  165)
* PyUnicode_Join (C function):           Methods and Slot Functions.
                                                             (line   77)
* PyUnicode_KIND (C function):           Unicode Type.       (line  107)
* PyUnicode_MAX_CHAR_VALUE (C function): Unicode Type.       (line  155)
* PyUnicode_New (C function):            Creating and accessing Unicode strings.
                                                             (line    9)
* PyUnicode_Partition (C function):      Methods and Slot Functions.
                                                             (line   48)
* PyUnicode_READ (C function):           Unicode Type.       (line  137)
* PyUnicode_READ_CHAR (C function):      Unicode Type.       (line  146)
* PyUnicode_ReadChar (C function):       Creating and accessing Unicode strings.
                                                             (line  366)
* PyUnicode_READY (C function):          Unicode Type.       (line   64)
* PyUnicode_Replace (C function):        Methods and Slot Functions.
                                                             (line  124)
* PyUnicode_RichCompare (C function):    Methods and Slot Functions.
                                                             (line  172)
* PyUnicode_RPartition (C function):     Methods and Slot Functions.
                                                             (line   63)
* PyUnicode_RSplit (C function):         Methods and Slot Functions.
                                                             (line   30)
* PyUnicode_Split (C function):          Methods and Slot Functions.
                                                             (line   17)
* PyUnicode_Splitlines (C function):     Methods and Slot Functions.
                                                             (line   40)
* PyUnicode_Substring (C function):      Creating and accessing Unicode strings.
                                                             (line  378)
* PyUnicode_Tailmatch (C function):      Methods and Slot Functions.
                                                             (line   83)
* PyUnicode_Translate (C function):      Character Map Codecs.
                                                             (line   46)
* PyUnicode_Type (C var):                Unicode Type.       (line   41)
* PyUnicode_WRITE (C function):          Unicode Type.       (line  124)
* PyUnicode_WriteChar (C function):      Creating and accessing Unicode strings.
                                                             (line  350)
* PyUnicodeDecodeError_Create (C function): Unicode Exception Objects.
                                                             (line    9)
* PyUnicodeDecodeError_GetEncoding (C function): Unicode Exception Objects.
                                                             (line   17)
* PyUnicodeDecodeError_GetEnd (C function): Unicode Exception Objects.
                                                             (line   54)
* PyUnicodeDecodeError_GetObject (C function): Unicode Exception Objects.
                                                             (line   25)
* PyUnicodeDecodeError_GetReason (C function): Unicode Exception Objects.
                                                             (line   74)
* PyUnicodeDecodeError_GetStart (C function): Unicode Exception Objects.
                                                             (line   34)
* PyUnicodeDecodeError_SetEnd (C function): Unicode Exception Objects.
                                                             (line   64)
* PyUnicodeDecodeError_SetReason (C function): Unicode Exception Objects.
                                                             (line   83)
* PyUnicodeDecodeError_SetStart (C function): Unicode Exception Objects.
                                                             (line   44)
* PyUnicodeEncodeError_GetEncoding (C function): Unicode Exception Objects.
                                                             (line   17)
* PyUnicodeEncodeError_GetEnd (C function): Unicode Exception Objects.
                                                             (line   54)
* PyUnicodeEncodeError_GetObject (C function): Unicode Exception Objects.
                                                             (line   25)
* PyUnicodeEncodeError_GetReason (C function): Unicode Exception Objects.
                                                             (line   74)
* PyUnicodeEncodeError_GetStart (C function): Unicode Exception Objects.
                                                             (line   34)
* PyUnicodeEncodeError_SetEnd (C function): Unicode Exception Objects.
                                                             (line   64)
* PyUnicodeEncodeError_SetReason (C function): Unicode Exception Objects.
                                                             (line   83)
* PyUnicodeEncodeError_SetStart (C function): Unicode Exception Objects.
                                                             (line   44)
* PyUnicodeIter_Type (C var):            Unicode Type.       (line   46)
* PyUnicodeObject (C type):              Unicode Type.       (line   30)
* PyUnicodeTranslateError_GetEnd (C function): Unicode Exception Objects.
                                                             (line   54)
* PyUnicodeTranslateError_GetObject (C function): Unicode Exception Objects.
                                                             (line   25)
* PyUnicodeTranslateError_GetReason (C function): Unicode Exception Objects.
                                                             (line   74)
* PyUnicodeTranslateError_GetStart (C function): Unicode Exception Objects.
                                                             (line   34)
* PyUnicodeTranslateError_SetEnd (C function): Unicode Exception Objects.
                                                             (line   64)
* PyUnicodeTranslateError_SetReason (C function): Unicode Exception Objects.
                                                             (line   83)
* PyUnicodeTranslateError_SetStart (C function): Unicode Exception Objects.
                                                             (line   44)
* PyUnstable:                            Unstable C API.     (line    6)
* PyUnstable_AtExit (C function):        Initializing and finalizing the interpreter.
                                                             (line  207)
* PyUnstable_Code_GetExtra (C function): Extra information.  (line   35)
* PyUnstable_Code_GetFirstFree (C function): Code Objects<2>.
                                                             (line   31)
* PyUnstable_Code_New (C function):      Code Objects<2>.    (line   41)
* PyUnstable_Code_NewWithPosOnlyArgs (C function): Code Objects<2>.
                                                             (line   68)
* PyUnstable_Code_SetExtra (C function): Extra information.  (line   51)
* PyUnstable_Eval_RequestCodeExtraIndex (C function): Extra information.
                                                             (line   14)
* PyUnstable_Exc_PrepReraiseStar (C function): Exception Objects.
                                                             (line   70)
* PyUnstable_GC_VisitObjects (C function): Querying Garbage Collector State.
                                                             (line    9)
* PyUnstable_InterpreterFrame_GetCode (C function): Internal Frames.
                                                             (line   14)
* PyUnstable_InterpreterFrame_GetLasti (C function): Internal Frames.
                                                             (line   24)
* PyUnstable_InterpreterFrame_GetLine (C function): Internal Frames.
                                                             (line   32)
* PyUnstable_InterpreterState_GetMainModule (C function): Low-level API.
                                                             (line  157)
* PyUnstable_Long_CompactValue (C function): Integer Objects.
                                                             (line  547)
* PyUnstable_Long_IsCompact (C function): Integer Objects.   (line  529)
* PyUnstable_Module_SetGIL (C function): Support functions.  (line  158)
* PyUnstable_Object_ClearWeakRefsNoCallbacks (C function): Weak Reference Objects<2>.
                                                             (line  117)
* PyUnstable_Object_GC_NewWithExtraData (C function): Supporting Cyclic Garbage Collection.
                                                             (line   66)
* PyUnstable_PerfMapState_Fini (C function): Support for Perf Maps.
                                                             (line   48)
* PyUnstable_PerfMapState_Init (C function): Support for Perf Maps.
                                                             (line   19)
* PyUnstable_Type_AssignVersionTag (C function): Type Objects<2>.
                                                             (line  308)
* PyUnstable_WritePerfMapEntry (C function): Support for Perf Maps.
                                                             (line   33)
* PyVarObject (C type):                  Base object types and macros.
                                                             (line   26)
* PyVarObject_HEAD_INIT (C macro):       Base object types and macros.
                                                             (line  135)
* PyVarObject.ob_size (C member):        PyVarObject Slots.  (line    6)
* PyVectorcall_Call (C function):        Vectorcall Support API.
                                                             (line   33)
* PyVectorcall_Function (C function):    Vectorcall Support API.
                                                             (line   19)
* PyVectorcall_NARGS (C function):       Vectorcall Support API.
                                                             (line    6)
* PyWeakref_Check (C function):          Weak Reference Objects<2>.
                                                             (line   11)
* PyWeakref_CheckProxy (C function):     Weak Reference Objects<2>.
                                                             (line   26)
* PyWeakref_CheckRef (C function):       Weak Reference Objects<2>.
                                                             (line   16)
* PyWeakref_CheckRefExact (C function):  Weak Reference Objects<2>.
                                                             (line   21)
* PyWeakref_GET_OBJECT (C function):     Weak Reference Objects<2>.
                                                             (line  101)
* PyWeakref_GetObject (C function):      Weak Reference Objects<2>.
                                                             (line   85)
* PyWeakref_GetRef (C function):         Weak Reference Objects<2>.
                                                             (line   71)
* PyWeakref_NewProxy (C function):       Weak Reference Objects<2>.
                                                             (line   51)
* PyWeakref_NewRef (C function):         Weak Reference Objects<2>.
                                                             (line   31)
* PyWideStringList (C type):             PyWideStringList.   (line    6)
* PyWideStringList_Append (C function):  PyWideStringList.   (line   15)
* PyWideStringList_Insert (C function):  PyWideStringList.   (line   22)
* PyWideStringList.items (C member):     PyWideStringList.   (line   41)
* PyWideStringList.length (C member):    PyWideStringList.   (line   37)
* PyWrapper_New (C function):            Descriptor Objects. (line   72)
* PyWrapperDescr_Type (C var):           Descriptor Objects. (line   53)
* PyZip_Type (C var):                    Builtin Iterator Types.
                                                             (line   27)
* PyZipFile (class in zipfile):          PyZipFile objects.  (line   10)
* qiflush() (in module curses):          Functions<6>.       (line  397)
* QName (class in xml.etree.ElementTree): QName Objects.     (line    6)
* qsize() (asyncio.Queue method):        Queue.              (line   79)
* qsize() (multiprocessing.Queue method): Pipes and Queues.  (line  108)
* qsize() (queue.Queue method):          Queue Objects.      (line    9)
* qsize() (queue.SimpleQueue method):    SimpleQueue Objects.
                                                             (line    9)
* qualified name:                        Glossary.           (line 1421)
* quantiles() (in module statistics):    Function details.   (line  501)
* quantiles() (statistics.NormalDist method): NormalDist objects.
                                                             (line  109)
* quantize() (decimal.Context method):   Context objects.    (line  490)
* quantize() (decimal.Decimal method):   Decimal objects.    (line  473)
* QueryInfoKey() (in module winreg):     Functions<13>.      (line  318)
* QueryReflectionKey() (in module winreg): Functions<13>.    (line  515)
* QueryValue() (in module winreg):       Functions<13>.      (line  347)
* QueryValueEx() (in module winreg):     Functions<13>.      (line  367)
* QUESTION (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  196)
* Queue (class in asyncio):              Queue.              (line    6)
* Queue (class in multiprocessing):      Pipes and Queues.   (line   91)
* Queue (class in queue):                queue — A synchronized queue class.
                                                             (line   32)
* queue (sched.scheduler attribute):     Scheduler Objects.  (line   73)
* Queue() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  198)
* QueueEmpty:                            Exceptions<12>.     (line    6)
* QueueFull:                             Exceptions<12>.     (line   11)
* QueueHandler (class in logging.handlers): QueueHandler.    (line   21)
* QueueListener (class in logging.handlers): QueueListener.  (line   24)
* QueueShutDown:                         Exceptions<12>.     (line   16)
* quick_ratio() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  204)
* quiet (sys.flags attribute):           sys — System-specific parameters and functions.
                                                             (line  560)
* quit (built-in variable):              Constants added by the site module.
                                                             (line   11)
* quit (pdb command):                    Debugger commands.  (line  424)
* quit() (ftplib.FTP method):            FTP objects.        (line  359)
* quit() (poplib.POP3 method):           POP3 Objects.       (line   83)
* quit() (smtplib.SMTP method):          SMTP Objects.       (line  340)
* quit() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  123)
* quitting (bdb.Bdb attribute):          bdb — Debugger framework.
                                                             (line  331)
* QUOTE_ALL (in module csv):             Module Contents<2>. (line  271)
* quote_from_bytes() (in module urllib.parse): URL Quoting.  (line   53)
* QUOTE_MINIMAL (in module csv):         Module Contents<2>. (line  275)
* QUOTE_NONE (in module csv):            Module Contents<2>. (line  295)
* QUOTE_NONNUMERIC (in module csv):      Module Contents<2>. (line  281)
* QUOTE_NOTNULL (in module csv):         Module Contents<2>. (line  308)
* quote_plus() (in module urllib.parse): URL Quoting.        (line   42)
* QUOTE_STRINGS (in module csv):         Module Contents<2>. (line  320)
* quote() (in module email.utils):       email utils Miscellaneous utilities.
                                                             (line   45)
* quote() (in module shlex):             shlex — Simple lexical analysis.
                                                             (line   43)
* quote() (in module urllib.parse):      URL Quoting.        (line   13)
* quoteattr() (in module xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   38)
* quotechar (csv.Dialect attribute):     Dialects and Formatting Parameters.
                                                             (line   63)
* quoted-printable; encoding:            quopri — Encode and decode MIME quoted-printable data.
                                                             (line    8)
* quotes (shlex.shlex attribute):        shlex Objects.      (line  115)
* quoting (csv.Dialect attribute):       Dialects and Formatting Parameters.
                                                             (line   74)
* R_OK (in module os):                   Files and Directories.
                                                             (line  107)
* r'; raw string literal:                String and Bytes literals.
                                                             (line   51)
* r"; raw string literal:                String and Bytes literals.
                                                             (line   51)
* race condition:                        Glossary.           (line 1448)
* radians() (in module math):            Angular conversion. (line   10)
* radians() (in module turtle):          Settings for measurement.
                                                             (line   28)
* radix (sys.float_info attribute):      sys — System-specific parameters and functions.
                                                             (line  669)
* radix() (decimal.Context method):      Context objects.    (line  495)
* radix() (decimal.Decimal method):      Decimal objects.    (line  502)
* RADIXCHAR (in module locale):          locale — Internationalization services.
                                                             (line  279)
* Raise (class in ast):                  Statements.         (line  112)
* RAISE (monitoring event):              Events.             (line   71)
* raise an exception:                    Exceptions<2>.      (line    6)
* raise_on_defect (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  181)
* raise_signal() (in module signal):     Module contents<3>. (line  354)
* RAISE_VARARGS (opcode):                Python Bytecode Instructions.
                                                             (line 1023)
* raiseExceptions (in module logging):   Module-Level Attributes.
                                                             (line   19)
* raising; exception:                    The raise statement.
                                                             (line    6)
* RAND_add() (in module ssl):            Random generation.  (line   30)
* RAND_bytes() (in module ssl):          Random generation.  (line    6)
* RAND_status() (in module ssl):         Random generation.  (line   23)
* randbelow() (in module secrets):       Random numbers.     (line   19)
* randbits() (in module secrets):        Random numbers.     (line   23)
* randbytes() (in module random):        Functions for bytes.
                                                             (line    6)
* randbytes() (random.Random method):    Alternative Generator.
                                                             (line   46)
* randint() (in module random):          Functions for integers.
                                                             (line   32)
* Random (class in random):              Alternative Generator.
                                                             (line    6)
* random command line option; -c:        Command-line usage. (line   18)
* random command line option; -choice:   Command-line usage. (line   18)
* random command line option; -f:        Command-line usage. (line   29)
* random command line option; -float:    Command-line usage. (line   29)
* random command line option; -h:        Command-line usage. (line   14)
* random command line option; -help:     Command-line usage. (line   14)
* random command line option; -i:        Command-line usage. (line   23)
* random command line option; -integer:  Command-line usage. (line   23)
* random() (in module random):           Real-valued distributions.
                                                             (line   11)
* random() (random.Random method):       Alternative Generator.
                                                             (line   33)
* randrange() (in module random):        Functions for integers.
                                                             (line    6)
* range (built-in class):                Ranges.             (line   10)
* RARROW (in module token):              token — Constants used with Python parse trees.
                                                             (line  308)
* ratio() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  180)
* Rational (class in numbers):           The numeric tower.  (line   41)
* raw (io.BufferedIOBase attribute):     I/O Base Classes.   (line  249)
* raw string:                            String and Bytes literals.
                                                             (line   36)
* raw_data_manager (in module email.contentmanager): Content Manager Instances.
                                                             (line   11)
* raw_decode() (json.JSONDecoder method): Encoders and Decoders.
                                                             (line   95)
* raw_input() (code.InteractiveConsole method): Interactive Console Objects.
                                                             (line   45)
* raw() (in module curses):              Functions<6>.       (line  404)
* raw() (pickle.PickleBuffer method):    Module Interface.   (line  321)
* RawArray() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   16)
* RawConfigParser (class in configparser): RawConfigParser Objects.
                                                             (line    6)
* RawDescriptionHelpFormatter (class in argparse): formatter_class.
                                                             (line   10)
* RawIOBase (class in io):               I/O Base Classes.   (line  169)
* RawPen (class in turtle):              Public classes.     (line    6)
* RawTextHelpFormatter (class in argparse): formatter_class. (line   10)
* RawTurtle (class in turtle):           Public classes.     (line    6)
* RawValue() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   33)
* RBRACE (in module token):              token — Constants used with Python parse trees.
                                                             (line  233)
* re (re.Match attribute):               Match Objects.      (line  205)
* READ (inspect.BufferFlags attribute):  Buffer flags.       (line   49)
* read_binary() (in module importlib.resources): Functional API.
                                                             (line   75)
* read_byte() (mmap.mmap method):        mmap — Memory-mapped file support.
                                                             (line  254)
* read_bytes() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  553)
* read_bytes() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  153)
* read_bytes() (pathlib.Path method):    Reading and writing files.
                                                             (line   35)
* read_bytes() (zipfile.Path method):    Path objects.       (line  110)
* read_dict() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  207)
* read_environ() (in module wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line  310)
* read_events() (xml.etree.ElementTree.XMLPullParser method): XMLPullParser Objects.
                                                             (line   47)
* read_file() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  185)
* read_history_file() (in module readline): History file.    (line    8)
* read_init_file() (in module readline): Init file.          (line   13)
* read_mime_types() (in module mimetypes): mimetypes — Map filenames to MIME types.
                                                             (line  112)
* READ_RESTRICTED (C macro):             Member flags.       (line   31)
* read_string() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  197)
* read_text() (importlib.abc.Traversable method): importlib abc – Abstract base classes related to import.
                                                             (line  557)
* read_text() (importlib.resources.abc.Traversable method): importlib resources abc – Abstract base classes for resources.
                                                             (line  157)
* read_text() (in module importlib.resources): Functional API.
                                                             (line   89)
* read_text() (pathlib.Path method):     Reading and writing files.
                                                             (line   18)
* read_text() (zipfile.Path method):     Path objects.       (line   98)
* read_token() (shlex.shlex method):     shlex Objects.      (line   20)
* read_windows_registry() (mimetypes.MimeTypes method): MimeTypes Objects.
                                                             (line   93)
* read() (asyncio.StreamReader method):  StreamReader.       (line   20)
* read() (codecs.StreamReader method):   StreamReader Objects.
                                                             (line   34)
* read() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  148)
* read() (file method):                  I/O objects also known as file objects.
                                                             (line   22)
* read() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   13)
* read() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  202)
* read() (in module os):                 File Descriptor Operations.
                                                             (line  730)
* read() (io.BufferedIOBase method):     I/O Base Classes.   (line  270)
* read() (io.BufferedReader method):     Buffered Streams.   (line   80)
* read() (io.RawIOBase method):          I/O Base Classes.   (line  183)
* read() (io.TextIOBase method):         Text I/O<2>.        (line   51)
* read() (mimetypes.MimeTypes method):   MimeTypes Objects.  (line   77)
* read() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  244)
* read() (sqlite3.Blob method):          Blob objects.       (line   45)
* read() (ssl.MemoryBIO method):         Memory BIO support. (line  148)
* read() (ssl.SSLSocket method):         SSL sockets.        (line   76)
* read() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   25)
* read() (zipfile.ZipFile method):       ZipFile objects.    (line  244)
* read1() (bz2.BZ2File method):          De compression of files.
                                                             (line  110)
* read1() (io.BufferedIOBase method):    I/O Base Classes.   (line  294)
* read1() (io.BufferedReader method):    Buffered Streams.   (line   85)
* read1() (io.BytesIO method):           Buffered Streams.   (line   43)
* READABLE (in module _tkinter):         File Handlers.      (line   41)
* readable() (bz2.BZ2File method):       De compression of files.
                                                             (line   92)
* readable() (io.IOBase method):         I/O Base Classes.   (line   77)
* readall() (io.RawIOBase method):       I/O Base Classes.   (line  198)
* readbuffer_encode() (in module codecs): codecs — Codec registry and base classes.
                                                             (line  257)
* reader() (in module csv):              Module Contents<2>. (line    8)
* ReadError:                             tarfile — Read and write tar archive files.
                                                             (line  203)
* readexactly() (asyncio.StreamReader method): StreamReader. (line   46)
* readfp() (mimetypes.MimeTypes method): MimeTypes Objects.  (line   85)
* readframes() (wave.Wave_read method):  Wave_read Objects.  (line   52)
* readinto() (bz2.BZ2File method):       De compression of files.
                                                             (line  120)
* readinto() (http.client.HTTPResponse method): HTTPResponse Objects.
                                                             (line   17)
* readinto() (io.BufferedIOBase method): I/O Base Classes.   (line  306)
* readinto() (io.RawIOBase method):      I/O Base Classes.   (line  203)
* readinto1() (io.BufferedIOBase method): I/O Base Classes.  (line  319)
* readinto1() (io.BytesIO method):       Buffered Streams.   (line   49)
* readline() (asyncio.StreamReader method): StreamReader.    (line   35)
* readline() (codecs.StreamReader method): StreamReader Objects.
                                                             (line   60)
* readline() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  207)
* readline() (io.IOBase method):         I/O Base Classes.   (line   82)
* readline() (io.TextIOBase method):     Text I/O<2>.        (line   57)
* readline() (mmap.mmap method):         mmap — Memory-mapped file support.
                                                             (line  259)
* readlines() (codecs.StreamReader method): StreamReader Objects.
                                                             (line   71)
* readlines() (io.IOBase method):        I/O Base Classes.   (line   91)
* readlink() (in module os):             Files and Directories.
                                                             (line  670)
* readlink() (pathlib.Path method):      Expanding and resolving paths.
                                                             (line   80)
* readmodule_ex() (in module pyclbr):    pyclbr — Python module browser support.
                                                             (line   31)
* readmodule() (in module pyclbr):       pyclbr — Python module browser support.
                                                             (line   19)
* READONLY (C macro):                    Member flags.       (line   36)
* ReadOnly (in module typing):           Special forms.      (line  268)
* readonly (memoryview attribute):       Memory Views.       (line  420)
* ReadTransport (class in asyncio):      Transports Hierarchy.
                                                             (line   20)
* readuntil() (asyncio.StreamReader method): StreamReader.   (line   55)
* readv() (in module os):                File Descriptor Operations.
                                                             (line  867)
* ready() (multiprocessing.pool.AsyncResult method): Process Pools.
                                                             (line  215)
* Real (class in numbers):               The numeric tower.  (line   28)
* real (numbers.Complex attribute):      The numeric tower.  (line   15)
* real_max_memuse (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  149)
* real_quick_ratio() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line  209)
* realloc (C function):                  Overview<4>.        (line   33)
* realpath() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  379)
* REALTIME_PRIORITY_CLASS (in module subprocess): Windows Constants.
                                                             (line  103)
* reap_children() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  588)
* reap_threads() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   17)
* reason (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   65)
* reason (ssl.SSLError attribute):       Exceptions<16>.     (line   27)
* reason (UnicodeError attribute):       Concrete exceptions.
                                                             (line  447)
* reason (urllib.error.HTTPError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   48)
* reason (urllib.error.URLError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   21)
* reattach() (tkinter.ttk.Treeview method): ttk Treeview.    (line  237)
* rebinding; name:                       Assignment statements.
                                                             (line    6)
* recent() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  212)
* recipients (smtplib.SMTPRecipientsRefused attribute): smtplib — SMTP protocol client.
                                                             (line  162)
* reconfigure() (io.TextIOWrapper method): Text I/O<2>.      (line  181)
* record_original_stdout() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  312)
* RECORDS (inspect.BufferFlags attribute): Buffer flags.     (line   41)
* records (unittest.TestCase attribute): Test cases.         (line  431)
* RECORDS_RO (inspect.BufferFlags attribute): Buffer flags.  (line   43)
* rect() (in module cmath):              Conversions to and from polar coordinates.
                                                             (line   44)
* rectangle() (in module curses.textpad): curses textpad — Text input widget for curses programs.
                                                             (line   15)
* RecursionError:                        Concrete exceptions.
                                                             (line  243)
* recursive_repr() (in module reprlib):  reprlib — Alternate repr implementation.
                                                             (line   61)
* recv_bytes_into() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   79)
* recv_bytes() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   65)
* recv_fds() (in module socket):         Other functions<2>. (line  473)
* recv_into() (socket.socket method):    Socket Objects.     (line  385)
* recv() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   24)
* recv() (socket.socket method):         Socket Objects.     (line  232)
* recvfrom_into() (socket.socket method): Socket Objects.    (line  375)
* recvfrom() (socket.socket method):     Socket Objects.     (line  246)
* recvmsg_into() (socket.socket method): Socket Objects.     (line  337)
* recvmsg() (socket.socket method):      Socket Objects.     (line  265)
* redirect_request() (urllib.request.HTTPRedirectHandler method): HTTPRedirectHandler Objects.
                                                             (line   15)
* redirect_stderr() (in module contextlib): Utilities.       (line  353)
* redirect_stdout() (in module contextlib): Utilities.       (line  312)
* redisplay() (in module readline):      Line buffer.        (line   19)
* redrawln() (curses.window method):     Window Objects.     (line  463)
* redrawwin() (curses.window method):    Window Objects.     (line  469)
* reduce() (in module functools):        functools — Higher-order functions and operations on callable objects.
                                                             (line  393)
* reducer_override() (pickle.Pickler method): Module Interface.
                                                             (line  202)
* reentrant:                             Glossary.           (line 1482)
* ref (class in weakref):                weakref — Weak references.
                                                             (line   88)
* refcount_test() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  547)
* reference count:                       Glossary.           (line 1459)
* reference counting:                    Objects values and types.
                                                             (line   36)
* ReferenceError:                        Concrete exceptions.
                                                             (line  252)
* ReferenceType (in module weakref):     weakref — Weak references.
                                                             (line  330)
* refold_source (email.policy.EmailPolicy attribute): email policy Policy Objects.
                                                             (line  387)
* refresh() (curses.window method):      Window Objects.     (line  474)
* REG_BINARY (in module winreg):         Value Types.        (line    8)
* REG_DWORD (in module winreg):          Value Types.        (line   12)
* REG_DWORD_BIG_ENDIAN (in module winreg): Value Types.      (line   21)
* REG_DWORD_LITTLE_ENDIAN (in module winreg): Value Types.   (line   16)
* REG_EXPAND_SZ (in module winreg):      Value Types.        (line   25)
* REG_FULL_RESOURCE_DESCRIPTOR (in module winreg): Value Types.
                                                             (line   60)
* REG_LINK (in module winreg):           Value Types.        (line   30)
* REG_MULTI_SZ (in module winreg):       Value Types.        (line   34)
* REG_NONE (in module winreg):           Value Types.        (line   39)
* REG_QWORD (in module winreg):          Value Types.        (line   43)
* REG_QWORD_LITTLE_ENDIAN (in module winreg): Value Types.   (line   49)
* REG_RESOURCE_LIST (in module winreg):  Value Types.        (line   56)
* REG_RESOURCE_REQUIREMENTS_LIST (in module winreg): Value Types.
                                                             (line   64)
* REG_SZ (in module winreg):             Value Types.        (line   68)
* RegexFlag (class in re):               Flags.              (line    9)
* register_adapter() (in module sqlite3): Module functions.  (line  138)
* register_archive_format() (in module shutil): Archiving operations.
                                                             (line   91)
* register_at_fork() (in module os):     Process Management. (line  552)
* register_callback() (in module sys.monitoring): Registering callback functions.
                                                             (line    8)
* register_converter() (in module sqlite3): Module functions.
                                                             (line  145)
* register_defect() (email.policy.Policy method): email policy Policy Objects.
                                                             (line  245)
* register_dialect() (in module csv):    Module Contents<2>. (line   70)
* register_error() (in module codecs):   Error Handlers.     (line  101)
* register_function() (xmlrpc.server.CGIXMLRPCRequestHandler method): CGIXMLRPCRequestHandler.
                                                             (line    9)
* register_function() (xmlrpc.server.SimpleXMLRPCServer method): SimpleXMLRPCServer objects.
                                                             (line   10)
* register_instance() (xmlrpc.server.CGIXMLRPCRequestHandler method): CGIXMLRPCRequestHandler.
                                                             (line   26)
* register_instance() (xmlrpc.server.SimpleXMLRPCServer method): SimpleXMLRPCServer objects.
                                                             (line   27)
* register_introspection_functions() (xmlrpc.server.CGIXMLRPCRequestHandler method): CGIXMLRPCRequestHandler.
                                                             (line   41)
* register_introspection_functions() (xmlrpc.server.SimpleXMLRPCServer method): SimpleXMLRPCServer objects.
                                                             (line   55)
* register_multicall_functions() (xmlrpc.server.CGIXMLRPCRequestHandler method): CGIXMLRPCRequestHandler.
                                                             (line   46)
* register_multicall_functions() (xmlrpc.server.SimpleXMLRPCServer method): SimpleXMLRPCServer objects.
                                                             (line   60)
* register_namespace() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  198)
* register_optionflag() (in module doctest): Option Flags.   (line  153)
* register_shape() (in module turtle):   Settings and special methods.
                                                             (line   71)
* register_unpack_format() (in module shutil): Archiving operations.
                                                             (line  161)
* register() (abc.ABCMeta method):       abc — Abstract Base Classes.
                                                             (line   69)
* register() (argparse.ArgumentParser method): Registering custom types or actions.
                                                             (line    6)
* register() (functools.singledispatch method): functools — Higher-order functions and operations on callable objects.
                                                             (line  440)
* register() (in module atexit):         atexit — Exit handlers.
                                                             (line   25)
* register() (in module codecs):         codecs — Codec registry and base classes.
                                                             (line  159)
* register() (in module faulthandler):   Dumping the traceback on a user signal.
                                                             (line    6)
* register() (in module webbrowser):     Command-line interface<4>.
                                                             (line   74)
* register() (multiprocessing.managers.BaseManager method): Managers.
                                                             (line   93)
* register() (select.devpoll method):    /dev/poll Polling Objects.
                                                             (line   30)
* register() (select.epoll method):      Edge and Level Trigger Polling epoll Objects.
                                                             (line   81)
* register() (select.poll method):       Polling Objects.    (line   15)
* register() (selectors.BaseSelector method): Classes<4>.    (line   65)
* registerDOMImplementation() (in module xml.dom): Module Contents<3>.
                                                             (line    8)
* registerResult() (in module unittest): Signal Handling.    (line   35)
* REGTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  277)
* regular package:                       Glossary.           (line 1475)
* relative_to() (pathlib.PurePath method): Methods and properties.
                                                             (line  309)
* relative; import:                      The import statement.
                                                             (line  100)
* relative; URL:                         urllib parse — Parse URLs into components.
                                                             (line    8)
* release() (_thread.lock method):       _thread — Low-level threading API.
                                                             (line  170)
* release() (asyncio.Condition method):  Condition.          (line   78)
* release() (asyncio.Lock method):       Lock.               (line   49)
* release() (asyncio.Semaphore method):  Semaphore.          (line   54)
* release() (in module platform):        Cross platform.     (line  117)
* release() (logging.Handler method):    Handler Objects.    (line   31)
* release() (memoryview method):         Memory Views.       (line  240)
* release() (multiprocessing.Lock method): Synchronization primitives.
                                                             (line  106)
* release() (multiprocessing.RLock method): Synchronization primitives.
                                                             (line  165)
* release() (pickle.PickleBuffer method): Module Interface.  (line  329)
* release() (threading.Condition method): Condition objects. (line   91)
* release() (threading.Lock method):     Lock objects.       (line   72)
* release() (threading.RLock method):    RLock objects.      (line   94)
* release() (threading.Semaphore method): Semaphore objects. (line   62)
* releasebufferproc (C type):            Slot Type typedefs. (line  104)
* reload() (in module importlib):        Functions<12>.      (line   53)
* relpath() (in module os.path):         os path — Common pathname manipulations.
                                                             (line  435)
* remainder_near() (decimal.Context method): Context objects.
                                                             (line  506)
* remainder_near() (decimal.Decimal method): Decimal objects.
                                                             (line  508)
* remainder() (decimal.Context method):  Context objects.    (line  499)
* remainder() (in module math):          Floating point arithmetic.
                                                             (line   65)
* RemoteDisconnected:                    http client — HTTP protocol client.
                                                             (line  187)
* remove_child_handler() (asyncio.AbstractChildWatcher method): Process Watchers.
                                                             (line   56)
* remove_done_callback() (asyncio.Future method): Future Object.
                                                             (line  106)
* remove_done_callback() (asyncio.Task method): Task object. (line  111)
* remove_flag() (mailbox.Maildir method): Maildir objects.   (line  142)
* remove_flag() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   84)
* remove_flag() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   85)
* remove_flag() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   84)
* remove_folder() (mailbox.Maildir method): Maildir objects. (line   80)
* remove_folder() (mailbox.MH method):   MH objects.         (line   50)
* remove_header() (urllib.request.Request method): Request Objects.
                                                             (line   99)
* remove_history_item() (in module readline): History list.  (line   26)
* remove_label() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   59)
* remove_option() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  306)
* remove_option() (optparse.OptionParser method): Querying and manipulating your option parser.
                                                             (line   47)
* remove_reader() (asyncio.loop method): Watching file descriptors.
                                                             (line   15)
* remove_section() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  313)
* remove_sequence() (mailbox.MHMessage method): MHMessage objects.
                                                             (line   46)
* remove_signal_handler() (asyncio.loop method): Unix signals.
                                                             (line   27)
* remove_writer() (asyncio.loop method): Watching file descriptors.
                                                             (line   32)
* remove() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  222)
* remove() (collections.deque method):   deque objects.      (line   97)
* remove() (in module os):               Files and Directories.
                                                             (line  707)
* remove() (mailbox.Mailbox method):     Mailbox objects.    (line   76)
* remove() (mailbox.MH method):          MH objects.         (line   79)
* remove() (sequence method):            Mutable Sequence Types.
                                                             (line  108)
* remove() (set method):                 Set Types — set frozenset.
                                                             (line  201)
* remove() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line  169)
* removeAttribute() (xml.dom.Element method): Element Objects<2>.
                                                             (line   52)
* removeAttributeNode() (xml.dom.Element method): Element Objects<2>.
                                                             (line   57)
* removeAttributeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   62)
* removeChild() (xml.dom.Node method):   Node Objects.       (line  128)
* removedirs() (in module os):           Files and Directories.
                                                             (line  731)
* removeFilter() (logging.Handler method): Handler Objects.  (line   57)
* removeFilter() (logging.Logger method): Logger Objects.    (line  329)
* removeHandler() (in module unittest):  Signal Handling.    (line   52)
* removeHandler() (logging.Logger method): Logger Objects.   (line  346)
* removeprefix() (bytearray method):     Bytes and Bytearray Operations.
                                                             (line   52)
* removeprefix() (bytes method):         Bytes and Bytearray Operations.
                                                             (line   52)
* removeprefix() (str method):           String Methods<2>.  (line  556)
* removeResult() (in module unittest):   Signal Handling.    (line   46)
* removesuffix() (bytearray method):     Bytes and Bytearray Operations.
                                                             (line   72)
* removesuffix() (bytes method):         Bytes and Bytearray Operations.
                                                             (line   72)
* removesuffix() (str method):           String Methods<2>.  (line  571)
* removexattr() (in module os):          Linux extended attributes.
                                                             (line   41)
* rename() (ftplib.FTP method):          FTP objects.        (line  324)
* rename() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  217)
* rename() (in module os):               Files and Directories.
                                                             (line  748)
* rename() (pathlib.Path method):        Renaming and deleting.
                                                             (line    6)
* renames() (in module os):              Files and Directories.
                                                             (line  785)
* reopenIfNeeded() (logging.handlers.WatchedFileHandler method): WatchedFileHandler.
                                                             (line   41)
* reorganize() (dbm.gnu.gdbm method):    dbm gnu — GNU database manager.
                                                             (line  119)
* repeat() (in module itertools):        Itertool Functions. (line  529)
* repeat() (in module timeit):           Python Interface.   (line   18)
* repeat() (timeit.Timer method):        Python Interface.   (line  109)
* repetition; operation:                 Common Sequence Operations.
                                                             (line   21)
* REPL:                                  Glossary.           (line 1502)
* replace_errors() (in module codecs):   Error Handlers.     (line  154)
* replace_header() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  301)
* replace_header() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  409)
* replace_history_item() (in module readline): History list. (line   32)
* replace_whitespace (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  181)
* replace; error handler's name:         Error Handlers.     (line   15)
* replace() (bytearray method):          Bytes and Bytearray Operations.
                                                             (line  200)
* replace() (bytes method):              Bytes and Bytearray Operations.
                                                             (line  200)
* replace() (codeobject method):         Methods on code objects.
                                                             (line   85)
* replace() (curses.panel.Panel method): Panel Objects.      (line   39)
* replace() (datetime.date method):      date Objects.       (line  194)
* replace() (datetime.datetime method):  datetime Objects.   (line  462)
* replace() (datetime.time method):      time Objects.       (line  149)
* replace() (in module copy):            copy — Shallow and deep copy operations.
                                                             (line   26)
* replace() (in module dataclasses):     Module contents<5>. (line  439)
* replace() (in module os):              Files and Directories.
                                                             (line  803)
* replace() (inspect.Parameter method):  Introspecting callables with the Signature object.
                                                             (line  300)
* replace() (inspect.Signature method):  Introspecting callables with the Signature object.
                                                             (line  136)
* replace() (pathlib.Path method):       Renaming and deleting.
                                                             (line   34)
* replace() (str method):                String Methods<2>.  (line  586)
* replace() (tarfile.TarInfo method):    TarInfo Objects.    (line  166)
* replaceChild() (xml.dom.Node method):  Node Objects.       (line  135)
* ReplacePackage() (in module modulefinder): modulefinder — Find modules used by a script.
                                                             (line   21)
* REPORT_CDIFF (in module doctest):      Option Flags.       (line  113)
* REPORT_ERRMODE (in module msvcrt):     Other Functions.    (line   35)
* report_failure() (doctest.DocTestRunner method): DocTestRunner objects.
                                                             (line   76)
* report_full_closure() (filecmp.dircmp method): The dircmp class.
                                                             (line   32)
* REPORT_NDIFF (in module doctest):      Option Flags.       (line  118)
* REPORT_ONLY_FIRST_FAILURE (in module doctest): Option Flags.
                                                             (line  127)
* report_partial_closure() (filecmp.dircmp method): The dircmp class.
                                                             (line   27)
* report_start() (doctest.DocTestRunner method): DocTestRunner objects.
                                                             (line   54)
* report_success() (doctest.DocTestRunner method): DocTestRunner objects.
                                                             (line   65)
* REPORT_UDIFF (in module doctest):      Option Flags.       (line  108)
* report_unexpected_exception() (doctest.DocTestRunner method): DocTestRunner objects.
                                                             (line   87)
* report() (filecmp.dircmp method):      The dircmp class.   (line   22)
* report() (modulefinder.ModuleFinder method): modulefinder — Find modules used by a script.
                                                             (line   38)
* REPORTING_FLAGS (in module doctest):   Option Flags.       (line  146)
* Repr (class in reprlib):               reprlib — Alternate repr implementation.
                                                             (line   17)
* repr() (built-in function); __repr__() (object method): Basic customization.
                                                             (line  112)
* repr() (in module reprlib):            reprlib — Alternate repr implementation.
                                                             (line   51)
* repr() (reprlib.Repr method):          Repr Objects.       (line  107)
* repr1() (reprlib.Repr method):         Repr Objects.       (line  112)
* ReprEnum (class in enum):              Data types.         (line  635)
* reprfunc (C type):                     Slot Type typedefs. (line   39)
* Request (class in urllib.request):     urllib request — Extensible library for opening URLs.
                                                             (line  188)
* request (socketserver.BaseRequestHandler attribute): Request Handler Objects.
                                                             (line   42)
* request_queue_size (socketserver.BaseServer attribute): Server Objects.
                                                             (line  101)
* request_rate() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   60)
* request_uri() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line   27)
* request_version (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  103)
* request() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line    8)
* RequestHandlerClass (socketserver.BaseServer attribute): Server Objects.
                                                             (line   74)
* requestline (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   85)
* Required (in module typing):           Special forms.      (line  249)
* requires_bz2() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  511)
* requires_docstrings() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  523)
* requires_freebsd_version() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  479)
* requires_gil_enabled() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  494)
* requires_gzip() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  507)
* requires_IEEE_754() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  499)
* requires_limited_api() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  527)
* requires_linux_version() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  484)
* requires_lzma() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  515)
* requires_mac_version() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  489)
* requires_resource() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  519)
* requires_zlib() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  503)
* requires() (in module importlib.metadata): Distribution requirements.
                                                             (line    6)
* requires() (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line  263)
* RERAISE (monitoring event):            Events.             (line   76)
* RERAISE (opcode):                      Python Bytecode Instructions.
                                                             (line  449)
* reschedule() (asyncio.Timeout method): Timeouts.           (line   72)
* reserved (zipfile.ZipInfo attribute):  ZipInfo objects.    (line  126)
* reserved word:                         Keywords.           (line    6)
* RESERVED_FUTURE (in module uuid):      uuid — UUID objects according to RFC 4122.
                                                             (line  239)
* RESERVED_MICROSOFT (in module uuid):   uuid — UUID objects according to RFC 4122.
                                                             (line  235)
* RESERVED_NCS (in module uuid):         uuid — UUID objects according to RFC 4122.
                                                             (line  227)
* reset_mock() (unittest.mock.AsyncMock method): The Mock Class.
                                                             (line  891)
* reset_mock() (unittest.mock.Mock method): The Mock Class.  (line  200)
* reset_peak() (in module tracemalloc):  Functions<11>.      (line   37)
* reset_prog_mode() (in module curses):  Functions<6>.       (line  410)
* reset_shell_mode() (in module curses): Functions<6>.       (line  415)
* reset_tzpath() (in module zoneinfo):   Functions<3>.       (line   27)
* reset() (asyncio.Barrier method):      Barrier.            (line   77)
* reset() (bdb.Bdb method):              bdb — Debugger framework.
                                                             (line  153)
* reset() (codecs.IncrementalDecoder method): IncrementalDecoder Objects.
                                                             (line   39)
* reset() (codecs.IncrementalEncoder method): IncrementalEncoder Objects.
                                                             (line   35)
* reset() (codecs.StreamReader method):  StreamReader Objects.
                                                             (line   83)
* reset() (codecs.StreamWriter method):  StreamWriter Objects.
                                                             (line   42)
* reset() (contextvars.ContextVar method): Context Variables.
                                                             (line   58)
* reset() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line   23)
* reset() (in module turtle):            More drawing control.
                                                             (line    6)
* reset() (threading.Barrier method):    Barrier objects.    (line   70)
* reset() (xml.dom.pulldom.DOMEventStream method): DOMEventStream Objects.
                                                             (line   37)
* reset() (xml.sax.xmlreader.IncrementalParser method): IncrementalParser Objects.
                                                             (line   19)
* resetbuffer() (code.InteractiveConsole method): Interactive Console Objects.
                                                             (line   41)
* resetscreen() (in module turtle):      Window control.     (line   86)
* resetty() (in module curses):          Functions<6>.       (line  420)
* resetwarnings() (in module warnings):  Available Functions.
                                                             (line  134)
* resize_term() (in module curses):      Functions<6>.       (line  425)
* resize() (curses.window method):       Window Objects.     (line  493)
* resize() (in module ctypes):           Utility functions.  (line  195)
* resize() (mmap.mmap method):           mmap — Memory-mapped file support.
                                                             (line  265)
* resizemode() (in module turtle):       Appearance.         (line   24)
* resizeterm() (in module curses):       Functions<6>.       (line  435)
* resolution (datetime.date attribute):  date Objects.       (line  109)
* resolution (datetime.datetime attribute): datetime Objects.
                                                             (line  297)
* resolution (datetime.time attribute):  time Objects.       (line   42)
* resolution (datetime.timedelta attribute): timedelta Objects.
                                                             (line  104)
* resolve_bases() (in module types):     Dynamic Type Creation.
                                                             (line   58)
* resolve_name() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line   80)
* resolve_name() (in module pkgutil):    pkgutil — Package extension utility.
                                                             (line  232)
* resolve() (pathlib.Path method):       Expanding and resolving paths.
                                                             (line   49)
* resolveEntity() (xml.sax.handler.EntityResolver method): EntityResolver Objects.
                                                             (line    6)
* resource_path() (importlib.abc.ResourceReader method): importlib abc – Abstract base classes related to import.
                                                             (line  475)
* resource_path() (importlib.resources.abc.ResourceReader method): importlib resources abc – Abstract base classes for resources.
                                                             (line   55)
* ResourceDenied:                        test support — Utilities for the Python test suite.
                                                             (line   22)
* ResourceLoader (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  172)
* ResourceReader (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  430)
* ResourceReader (class in importlib.resources.abc): importlib resources abc – Abstract base classes for resources.
                                                             (line   12)
* ResourceWarning:                       Warnings.           (line   85)
* response() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  221)
* ResponseNotReady:                      http client — HTTP protocol client.
                                                             (line  173)
* responses (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  178)
* responses (in module http.client):     http client — HTTP protocol client.
                                                             (line  208)
* restart (pdb command):                 Debugger commands.  (line  415)
* restart_events() (in module sys.monitoring): Disabling events.
                                                             (line   25)
* restore() (in module difflib):         difflib — Helpers for computing deltas.
                                                             (line  270)
* restore() (test.support.SaveSignals method): test support — Utilities for the Python test suite.
                                                             (line  779)
* RESTRICTED (C macro):                  Member flags.       (line   31)
* restricted; execution:                 Builtins and restricted execution.
                                                             (line    6)
* restype (ctypes._CFuncPtr attribute):  Foreign functions.  (line   32)
* result() (asyncio.Future method):      Future Object.      (line   32)
* result() (asyncio.Task method):        Task object.        (line   73)
* result() (concurrent.futures.Future method): Future Objects.
                                                             (line   37)
* results() (trace.Trace method):        Programmatic Interface.
                                                             (line   40)
* RESUME (opcode):                       Python Bytecode Instructions.
                                                             (line 1227)
* resume_reading() (asyncio.ReadTransport method): Read-only Transports.
                                                             (line   21)
* resume_writing() (asyncio.BaseProtocol method): Base Protocol.
                                                             (line   44)
* retr() (poplib.POP3 method):           POP3 Objects.       (line   63)
* retrbinary() (ftplib.FTP method):      FTP objects.        (line  174)
* retrieve() (urllib.request.URLopener method): Legacy interface.
                                                             (line  112)
* retrlines() (ftplib.FTP method):       FTP objects.        (line  199)
* RETRY (in module tkinter.messagebox):  tkinter messagebox — Tkinter message prompts.
                                                             (line  149)
* RETRYCANCEL (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  176)
* Return (class in ast):                 Function and class definitions.
                                                             (line  114)
* return (pdb command):                  Debugger commands.  (line  221)
* return_annotation (inspect.Signature attribute): Introspecting callables with the Signature object.
                                                             (line  115)
* RETURN_CONST (opcode):                 Python Bytecode Instructions.
                                                             (line  414)
* RETURN_GENERATOR (opcode):             Python Bytecode Instructions.
                                                             (line 1252)
* return_ok() (http.cookiejar.CookiePolicy method): CookiePolicy Objects.
                                                             (line   18)
* RETURN_VALUE (opcode):                 Python Bytecode Instructions.
                                                             (line  410)
* return_value (unittest.mock.Mock attribute): The Mock Class.
                                                             (line  342)
* returncode (asyncio.subprocess.Process attribute): Interacting with Subprocesses.
                                                             (line  146)
* returncode (subprocess.CalledProcessError attribute): Using the subprocess Module.
                                                             (line  211)
* returncode (subprocess.CompletedProcess attribute): Using the subprocess Module.
                                                             (line  110)
* returncode (subprocess.Popen attribute): Popen Objects.    (line  156)
* retval (pdb command):                  Debugger commands.  (line  434)
* reveal_type() (in module typing):      Functions and decorators.
                                                             (line   82)
* reverse_order() (pstats.Stats method): The Stats Class.    (line  157)
* reverse_pointer (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   77)
* reverse_pointer (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  269)
* reverse() (array.array method):        array — Efficient arrays of numeric values.
                                                             (line  232)
* reverse() (collections.deque method):  deque objects.      (line  102)
* reverse() (sequence method):           Mutable Sequence Types.
                                                             (line  115)
* Reversible (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   48)
* Reversible (class in typing):          Aliases to other ABCs in collections abc.
                                                             (line   60)
* revert() (http.cookiejar.FileCookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line  142)
* rewind() (wave.Wave_read method):      Wave_read Objects.  (line   57)
* RFC_4122 (in module uuid):             uuid — UUID objects according to RFC 4122.
                                                             (line  231)
* RFC; RFC 1123:                         Functions<5>.       (line  749)
* RFC; RFC 1123 <1>:                     Functions<5>.       (line  762)
* RFC; RFC 1123 <2>:                     Functions<5>.       (line  779)
* RFC; RFC 1321:                         hashlib — Secure hashes and message digests.
                                                             (line   15)
* RFC; RFC 1422:                         Certificates.       (line   38)
* RFC; RFC 1422 <1>:                     TLS 1 3.            (line   41)
* RFC; RFC 1521:                         Security Considerations<2>.
                                                             (line   18)
* RFC; RFC 1521 <1>:                     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   11)
* RFC; RFC 1521 <2>:                     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   37)
* RFC; RFC 1522:                         binascii — Convert between binary and ASCII.
                                                             (line   86)
* RFC; RFC 1522 <1>:                     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   25)
* RFC; RFC 1522 <2>:                     quopri — Encode and decode MIME quoted-printable data.
                                                             (line   39)
* RFC; RFC 1730:                         imaplib — IMAP4 protocol client.
                                                             (line   14)
* RFC; RFC 1738:                         URL Parsing.        (line  268)
* RFC; RFC 1738 <1>:                     URL Quoting.        (line  187)
* RFC; RFC 1750:                         Random generation.  (line   34)
* RFC; RFC 1808:                         urllib<2>.          (line   23)
* RFC; RFC 1808 <1>:                     urllib parse — Parse URLs into components.
                                                             (line   34)
* RFC; RFC 1808 <2>:                     URL Parsing.        (line   43)
* RFC; RFC 1808 <3>:                     URL Parsing.        (line  268)
* RFC; RFC 1808 <4>:                     URL Quoting.        (line  181)
* RFC; RFC 1869:                         smtplib — SMTP protocol client.
                                                             (line   13)
* RFC; RFC 1869 <1>:                     smtplib — SMTP protocol client.
                                                             (line  200)
* RFC; RFC 1870:                         smtpd<4>.           (line    6)
* RFC; RFC 1939:                         poplib — POP3 protocol client.
                                                             (line   11)
* RFC; RFC 1939 <1>:                     poplib — POP3 protocol client.
                                                             (line   13)
* RFC; RFC 2033:                         New and Improved Modules<2>.
                                                             (line  568)
* RFC; RFC 2045:                         email — An email and MIME handling package.
                                                             (line   15)
* RFC; RFC 2045 <1>:                     email message Representing an email message.
                                                             (line  316)
* RFC; RFC 2045 <2>:                     email message Representing an email message.
                                                             (line  317)
* RFC; RFC 2045 <3>:                     email message Representing an email message.
                                                             (line  321)
* RFC; RFC 2045 <4>:                     email headerregistry Custom Header Objects.
                                                             (line  238)
* RFC; RFC 2045 <5>:                     email headerregistry Custom Header Objects.
                                                             (line  296)
* RFC; RFC 2045 <6>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  422)
* RFC; RFC 2045 <7>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  426)
* RFC; RFC 2045 <8>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  429)
* RFC; RFC 2045 <9>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  526)
* RFC; RFC 2045 <10>:                    email header Internationalized headers.
                                                             (line   31)
* RFC; RFC 2045 <11>:                    base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line   24)
* RFC; RFC 2045 <12>:                    base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line   25)
* RFC; RFC 2045 <13>:                    Legacy Interface.   (line   29)
* RFC; RFC 2045 <14>:                    Legacy Interface.   (line   37)
* RFC; RFC 2045 Section 6.8:             Binary Objects.     (line   31)
* RFC; RFC 2046:                         email — An email and MIME handling package.
                                                             (line   15)
* RFC; RFC 2046 <1>:                     Content Manager Instances.
                                                             (line   93)
* RFC; RFC 2046 <2>:                     email header Internationalized headers.
                                                             (line   32)
* RFC; RFC 2047:                         PEP 3333 Python Web Server Gateway Interface v1 0 1.
                                                             (line   21)
* RFC; RFC 2047 <1>:                     email<6>.           (line   27)
* RFC; RFC 2047 <2>:                     Library.            (line  113)
* RFC; RFC 2047 <3>:                     email — An email and MIME handling package.
                                                             (line   15)
* RFC; RFC 2047 <4>:                     email policy Policy Objects.
                                                             (line  363)
* RFC; RFC 2047 <5>:                     email policy Policy Objects.
                                                             (line  369)
* RFC; RFC 2047 <6>:                     email headerregistry Custom Header Objects.
                                                             (line   78)
* RFC; RFC 2047 <7>:                     email headerregistry Custom Header Objects.
                                                             (line  123)
* RFC; RFC 2047 <8>:                     email headerregistry Custom Header Objects.
                                                             (line  128)
* RFC; RFC 2047 <9>:                     email header Internationalized headers.
                                                             (line   32)
* RFC; RFC 2047 <10>:                    email header Internationalized headers.
                                                             (line   54)
* RFC; RFC 2047 <11>:                    email header Internationalized headers.
                                                             (line  116)
* RFC; RFC 2047 <12>:                    email header Internationalized headers.
                                                             (line  140)
* RFC; RFC 2047 <13>:                    email utils Miscellaneous utilities.
                                                             (line   78)
* RFC; RFC 2060:                         imaplib — IMAP4 protocol client.
                                                             (line   13)
* RFC; RFC 2060 <1>:                     IMAP4 Objects.      (line  319)
* RFC; RFC 2068:                         http cookies — HTTP state management.
                                                             (line   16)
* RFC; RFC 2104:                         New and Improved Modules<3>.
                                                             (line   35)
* RFC; RFC 2104 <1>:                     hmac — Keyed-Hashing for Message Authentication.
                                                             (line   10)
* RFC; RFC 2109:                         http cookies — HTTP state management.
                                                             (line   15)
* RFC; RFC 2109 <1>:                     http cookies — HTTP state management.
                                                             (line   35)
* RFC; RFC 2109 <2>:                     http cookies — HTTP state management.
                                                             (line   65)
* RFC; RFC 2109 <3>:                     Morsel Objects.     (line    8)
* RFC; RFC 2109 <4>:                     Morsel Objects.     (line   11)
* RFC; RFC 2109 <5>:                     Morsel Objects.     (line   95)
* RFC; RFC 2109 <6>:                     Morsel Objects.     (line  107)
* RFC; RFC 2109 <7>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line   18)
* RFC; RFC 2109 <8>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  101)
* RFC; RFC 2109 <9>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  113)
* RFC; RFC 2109 <10>:                    http cookiejar — Cookie handling for HTTP clients.
                                                             (line  139)
* RFC; RFC 2109 <11>:                    DefaultCookiePolicy Objects.
                                                             (line   86)
* RFC; RFC 2109 <12>:                    Cookie Objects<2>.  (line   11)
* RFC; RFC 2109 <13>:                    Cookie Objects<2>.  (line   22)
* RFC; RFC 2109 <14>:                    Cookie Objects<2>.  (line   73)
* RFC; RFC 2183:                         email — An email and MIME handling package.
                                                             (line   16)
* RFC; RFC 2183 <1>:                     email message Representing an email message.
                                                             (line  460)
* RFC; RFC 2183 <2>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  633)
* RFC; RFC 2231:                         Library<9>.         (line   21)
* RFC; RFC 2231 <1>:                     Library<30>.        (line  135)
* RFC; RFC 2231 <2>:                     email — An email and MIME handling package.
                                                             (line   16)
* RFC; RFC 2231 <3>:                     email message Representing an email message.
                                                             (line  280)
* RFC; RFC 2231 <4>:                     email message Representing an email message.
                                                             (line  283)
* RFC; RFC 2231 <5>:                     email message Representing an email message.
                                                             (line  365)
* RFC; RFC 2231 <6>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  385)
* RFC; RFC 2231 <7>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  389)
* RFC; RFC 2231 <8>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  491)
* RFC; RFC 2231 <9>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  499)
* RFC; RFC 2231 <10>:                    email message Message Representing an email message using the compat32 API.
                                                             (line  533)
* RFC; RFC 2231 <11>:                    email header Internationalized headers.
                                                             (line   32)
* RFC; RFC 2231 <12>:                    email utils Miscellaneous utilities.
                                                             (line  188)
* RFC; RFC 2231 <13>:                    email utils Miscellaneous utilities.
                                                             (line  193)
* RFC; RFC 2231 <14>:                    email utils Miscellaneous utilities.
                                                             (line  202)
* RFC; RFC 2231 <15>:                    email utils Miscellaneous utilities.
                                                             (line  208)
* RFC; RFC 2231 <16>:                    email utils Miscellaneous utilities.
                                                             (line  217)
* RFC; RFC 2295:                         HTTP status codes.  (line  184)
* RFC; RFC 2324:                         HTTP status codes.  (line  133)
* RFC; RFC 2342:                         New and Improved Modules<3>.
                                                             (line   94)
* RFC; RFC 2342 <1>:                     IMAP4 Objects.      (line  167)
* RFC; RFC 2368:                         URL Quoting.        (line  177)
* RFC; RFC 2373:                         Address objects.    (line   95)
* RFC; RFC 2373 <1>:                     Address objects.    (line  161)
* RFC; RFC 2373 <2>:                     Address objects.    (line  181)
* RFC; RFC 2396:                         urllib parse<5>.    (line    6)
* RFC; RFC 2396 <1>:                     urllib<2>.          (line   24)
* RFC; RFC 2396 <2>:                     URL Quoting.        (line   25)
* RFC; RFC 2396 <3>:                     URL Quoting.        (line  172)
* RFC; RFC 2397:                         DataHandler Objects.
                                                             (line    9)
* RFC; RFC 2449:                         POP3 Objects.       (line   26)
* RFC; RFC 2487:                         New and Improved Modules<3>.
                                                             (line   86)
* RFC; RFC 2518:                         HTTP status codes.  (line   19)
* RFC; RFC 2595:                         poplib — POP3 protocol client.
                                                             (line   14)
* RFC; RFC 2595 <1>:                     POP3 Objects.       (line  116)
* RFC; RFC 2616:                         PEP 3333 Python Web Server Gateway Interface v1 0 1.
                                                             (line   20)
* RFC; RFC 2616 <1>:                     wsgiref util – WSGI environment utilities.
                                                             (line  115)
* RFC; RFC 2616 <2>:                     wsgiref validate — WSGI conformance checker.
                                                             (line   27)
* RFC; RFC 2616 <3>:                     HTTPRedirectHandler Objects.
                                                             (line    8)
* RFC; RFC 2616 <4>:                     HTTPRedirectHandler Objects.
                                                             (line   28)
* RFC; RFC 2616 <5>:                     Legacy interface.   (line  162)
* RFC; RFC 2616 <6>:                     urllib error — Exception classes raised by urllib request.
                                                             (line   43)
* RFC; RFC 2616 <7>:                     Introduction<16>.   (line   34)
* RFC; RFC 2616 <8>:                     HTTPError.          (line   15)
* RFC; RFC 2616 <9>:                     Error Codes.        (line   11)
* RFC; RFC 2616 Section 14.23:           HTTPConnection Objects.
                                                             (line   31)
* RFC; RFC 2616 Section 5.1.2:           HTTPConnection Objects.
                                                             (line   13)
* RFC; RFC 2616 Section 5.1.2 <1>:       HTTPConnection Objects.
                                                             (line   32)
* RFC; RFC 2640:                         Changes in the Python API<4>.
                                                             (line   36)
* RFC; RFC 2640 <1>:                     Tests<47>.          (line   22)
* RFC; RFC 2640 <2>:                     ftplib — FTP protocol client.
                                                             (line   17)
* RFC; RFC 2640 <3>:                     FTP objects.        (line   63)
* RFC; RFC 2640 <4>:                     FTP_TLS objects.    (line   64)
* RFC; RFC 2732:                         urllib parse<6>.    (line   10)
* RFC; RFC 2732 <1>:                     New and Improved Modules.
                                                             (line  642)
* RFC; RFC 2732 <2>:                     URL Quoting.        (line  168)
* RFC; RFC 2774:                         HTTP status codes.  (line  193)
* RFC; RFC 2818:                         ssl<12>.            (line   16)
* RFC; RFC 2821:                         email — An email and MIME handling package.
                                                             (line   12)
* RFC; RFC 2822:                         New and Improved Modules<3>.
                                                             (line   98)
* RFC; RFC 2822 <1>:                     Functions<5>.       (line  751)
* RFC; RFC 2822 <2>:                     Functions<5>.       (line  764)
* RFC; RFC 2822 <3>:                     Functions<5>.       (line  781)
* RFC; RFC 2822 <4>:                     email message Message Representing an email message using the compat32 API.
                                                             (line  275)
* RFC; RFC 2822 <5>:                     email header Internationalized headers.
                                                             (line   20)
* RFC; RFC 2822 <6>:                     email header Internationalized headers.
                                                             (line   23)
* RFC; RFC 2822 <7>:                     email header Internationalized headers.
                                                             (line   31)
* RFC; RFC 2822 <8>:                     email header Internationalized headers.
                                                             (line   87)
* RFC; RFC 2822 <9>:                     email header Internationalized headers.
                                                             (line  115)
* RFC; RFC 2822 <10>:                    email header Internationalized headers.
                                                             (line  133)
* RFC; RFC 2822 <11>:                    email utils Miscellaneous utilities.
                                                             (line   29)
* RFC; RFC 2822 <12>:                    email utils Miscellaneous utilities.
                                                             (line  109)
* RFC; RFC 2822 <13>:                    email utils Miscellaneous utilities.
                                                             (line  112)
* RFC; RFC 2822 <14>:                    email utils Miscellaneous utilities.
                                                             (line  235)
* RFC; RFC 2822 <15>:                    email utils Miscellaneous utilities.
                                                             (line  154)
* RFC; RFC 2964:                         http cookiejar — Cookie handling for HTTP clients.
                                                             (line  152)
* RFC; RFC 2965:                         urllib request — Extensible library for opening URLs.
                                                             (line  232)
* RFC; RFC 2965 <1>:                     urllib request — Extensible library for opening URLs.
                                                             (line  240)
* RFC; RFC 2965 <2>:                     Request Objects.    (line   50)
* RFC; RFC 2965 <3>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line   16)
* RFC; RFC 2965 <4>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  101)
* RFC; RFC 2965 <5>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  113)
* RFC; RFC 2965 <6>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  141)
* RFC; RFC 2965 <7>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  143)
* RFC; RFC 2965 <8>:                     http cookiejar — Cookie handling for HTTP clients.
                                                             (line  150)
* RFC; RFC 2965 <9>:                     FileCookieJar subclasses and co-operation with web browsers.
                                                             (line   16)
* RFC; RFC 2965 <10>:                    CookiePolicy Objects.
                                                             (line   73)
* RFC; RFC 2965 <11>:                    CookiePolicy Objects.
                                                             (line   78)
* RFC; RFC 2965 <12>:                    DefaultCookiePolicy Objects.
                                                             (line    8)
* RFC; RFC 2965 <13>:                    DefaultCookiePolicy Objects.
                                                             (line   90)
* RFC; RFC 2965 <14>:                    DefaultCookiePolicy Objects.
                                                             (line  101)
* RFC; RFC 2965 <15>:                    DefaultCookiePolicy Objects.
                                                             (line  105)
* RFC; RFC 2965 <16>:                    DefaultCookiePolicy Objects.
                                                             (line  114)
* RFC; RFC 2965 <17>:                    DefaultCookiePolicy Objects.
                                                             (line  151)
* RFC; RFC 2965 <18>:                    Cookie Objects<2>.  (line   22)
* RFC; RFC 2965 <19>:                    Examples<29>.       (line   24)
* RFC; RFC 3056:                         Address objects.    (line  316)
* RFC; RFC 3164:                         Logging to syslog with RFC5424 support.
                                                             (line    7)
* RFC; RFC 3171:                         Address objects.    (line   94)
* RFC; RFC 3207:                         New and Improved Modules<2>.
                                                             (line  573)
* RFC; RFC 3229:                         HTTP status codes.  (line   52)
* RFC; RFC 3280:                         SSL sockets.        (line  159)
* RFC; RFC 3330:                         Address objects.    (line  180)
* RFC; RFC 3339:                         Displaying the date/time in messages.
                                                             (line   18)
* RFC; RFC 3454:                         Security<23>.       (line   19)
* RFC; RFC 3454 <1>:                     stringprep — Internet String Preparation.
                                                             (line   17)
* RFC; RFC 3454 <2>:                     stringprep — Internet String Preparation.
                                                             (line   26)
* RFC; RFC 3490:                         Text Encodings.     (line   14)
* RFC; RFC 3490 <1>:                     encodings idna — Internationalized Domain Names in Applications.
                                                             (line    6)
* RFC; RFC 3490 <2>:                     encodings idna — Internationalized Domain Names in Applications.
                                                             (line   56)
* RFC; RFC 3490 <3>:                     encodings idna — Internationalized Domain Names in Applications.
                                                             (line   61)
* RFC; RFC 3490 Section 3.1:             encodings idna — Internationalized Domain Names in Applications.
                                                             (line   27)
* RFC; RFC 3491:                         Security<23>.       (line   21)
* RFC; RFC 3492:                         Text Encodings.     (line   36)
* RFC; RFC 3492 <1>:                     encodings idna — Internationalized Domain Names in Applications.
                                                             (line    7)
* RFC; RFC 3493:                         Example<7>.         (line  227)
* RFC; RFC 3501:                         IMAP4 Objects.      (line  330)
* RFC; RFC 3542:                         Library<138>.       (line  350)
* RFC; RFC 3542 <1>:                     Other functions<2>. (line  339)
* RFC; RFC 3548:                         New Improved and Deprecated Modules<3>.
                                                             (line   16)
* RFC; RFC 3548 <1>:                     binascii — Convert between binary and ASCII.
                                                             (line   50)
* RFC; RFC 3548 <2>:                     binascii — Convert between binary and ASCII.
                                                             (line   65)
* RFC; RFC 3596 Section 2.5:             Library<22>.        (line   14)
* RFC; RFC 3659:                         FTP objects.        (line  288)
* RFC; RFC 3879:                         Address objects.    (line  176)
* RFC; RFC 3879 <1>:                     Address objects.    (line  294)
* RFC; RFC 3927:                         Address objects.    (line  185)
* RFC; RFC 3986:                         urllib parse.       (line   17)
* RFC; RFC 3986 <1>:                     urllib parse<3>.    (line    7)
* RFC; RFC 3986 <2>:                     urllib parse<4>.    (line    7)
* RFC; RFC 3986 <3>:                     urllib parse<5>.    (line    6)
* RFC; RFC 3986 <4>:                     urllib<2>.          (line   22)
* RFC; RFC 3986 <5>:                     New and Improved Modules.
                                                             (line  621)
* RFC; RFC 3986 <6>:                     Porting to Python 2 7.
                                                             (line   80)
* RFC; RFC 3986 <7>:                     urllib parse — Parse URLs into components.
                                                             (line   35)
* RFC; RFC 3986 <8>:                     URL Parsing.        (line  118)
* RFC; RFC 3986 <9>:                     URL Parsing.        (line  144)
* RFC; RFC 3986 <10>:                    URL Parsing.        (line  271)
* RFC; RFC 3986 <11>:                    URL Parsing.        (line  319)
* RFC; RFC 3986 <12>:                    URL parsing security.
                                                             (line   25)
* RFC; RFC 3986 <13>:                    URL Quoting.        (line   25)
* RFC; RFC 3986 <14>:                    URL Quoting.        (line  160)
* RFC; RFC 3986 <15>:                    http server — HTTP servers.
                                                             (line  100)
* RFC; RFC 4007:                         Address objects.    (line  237)
* RFC; RFC 4007 <1>:                     Address objects.    (line  308)
* RFC; RFC 4086:                         TLS 1 3.            (line   45)
* RFC; RFC 4122:                         New Improved and Removed Modules.
                                                             (line  415)
* RFC; RFC 4122 <1>:                     New Improved and Removed Modules.
                                                             (line  420)
* RFC; RFC 4122 <2>:                     uuid — UUID objects according to RFC 4122.
                                                             (line    6)
* RFC; RFC 4122 <3>:                     uuid — UUID objects according to RFC 4122.
                                                             (line   15)
* RFC; RFC 4122 <4>:                     uuid — UUID objects according to RFC 4122.
                                                             (line   73)
* RFC; RFC 4122 <5>:                     uuid — UUID objects according to RFC 4122.
                                                             (line  138)
* RFC; RFC 4122 <6>:                     uuid — UUID objects according to RFC 4122.
                                                             (line  167)
* RFC; RFC 4122 <7>:                     uuid — UUID objects according to RFC 4122.
                                                             (line  233)
* RFC; RFC 4122 <8>:                     uuid — UUID objects according to RFC 4122.
                                                             (line  246)
* RFC; RFC 4180:                         csv — CSV File Reading and Writing.
                                                             (line   13)
* RFC; RFC 4193:                         Address objects.    (line  296)
* RFC; RFC 4217:                         FTP_TLS objects.    (line   11)
* RFC; RFC 4291:                         Library<39>.        (line 1074)
* RFC; RFC 4291 <1>:                     Library<92>.        (line  653)
* RFC; RFC 4291 <2>:                     Address objects.    (line  191)
* RFC; RFC 4291 <3>:                     Address objects.    (line  231)
* RFC; RFC 4380:                         Address objects.    (line  323)
* RFC; RFC 4627:                         json — JSON encoder and decoder.
                                                             (line   11)
* RFC; RFC 4627 <1>:                     Top-level Non-Object Non-Array Values.
                                                             (line    6)
* RFC; RFC 4648:                         Library.            (line   84)
* RFC; RFC 4648 <1>:                     Documentation<34>.  (line   32)
* RFC; RFC 4648 <2>:                     base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line   12)
* RFC; RFC 4648 <3>:                     base64 — Base16 Base32 Base64 Base85 Data Encodings.
                                                             (line   18)
* RFC; RFC 4648 <4>:                     RFC 4648 Encodings. (line    6)
* RFC; RFC 4648 <5>:                     RFC 4648 Encodings. (line   87)
* RFC; RFC 4648 <6>:                     RFC 4648 Encodings. (line  102)
* RFC; RFC 4648 <7>:                     RFC 4648 Encodings. (line  109)
* RFC; RFC 4648 <8>:                     Security Considerations<2>.
                                                             (line    6)
* RFC; RFC 4648 <9>:                     Security Considerations<3>.
                                                             (line    8)
* RFC; RFC 4918:                         HTTP status codes.  (line   46)
* RFC; RFC 4918 <1>:                     HTTP status codes.  (line  142)
* RFC; RFC 4918 <2>:                     HTTP status codes.  (line  145)
* RFC; RFC 4918 <3>:                     HTTP status codes.  (line  187)
* RFC; RFC 4954:                         SMTP Objects.       (line  134)
* RFC; RFC 4954 <1>:                     SMTP Objects.       (line  157)
* RFC; RFC 5161:                         imaplib<2>.         (line   11)
* RFC; RFC 5161 <1>:                     IMAP4 Objects.      (line   86)
* RFC; RFC 5246:                         Constants<9>.       (line  515)
* RFC; RFC 5246 <1>:                     TLS 1 3.            (line   53)
* RFC; RFC 5280:                         ssl.                (line   10)
* RFC; RFC 5280 <1>:                     Other Changes.      (line   20)
* RFC; RFC 5280 <2>:                     Changes in the Python API<9>.
                                                             (line   94)
* RFC; RFC 5280 <3>:                     Context creation.   (line   40)
* RFC; RFC 5280 <4>:                     Context creation.   (line   65)
* RFC; RFC 5280 <5>:                     Certificate handling.
                                                             (line   22)
* RFC; RFC 5280 <6>:                     TLS 1 3.            (line   49)
* RFC; RFC 5321:                         smtpd<4>.           (line    6)
* RFC; RFC 5321 <1>:                     email headerregistry Custom Header Objects.
                                                             (line  452)
* RFC; RFC 5322:                         Batteries included. (line   16)
* RFC; RFC 5322 <1>:                     Functions<5>.       (line  751)
* RFC; RFC 5322 <2>:                     Functions<5>.       (line  764)
* RFC; RFC 5322 <3>:                     Functions<5>.       (line  462)
* RFC; RFC 5322 <4>:                     Functions<5>.       (line  781)
* RFC; RFC 5322 <5>:                     email — An email and MIME handling package.
                                                             (line   14)
* RFC; RFC 5322 <6>:                     email message Representing an email message.
                                                             (line   20)
* RFC; RFC 5322 <7>:                     email message Representing an email message.
                                                             (line   31)
* RFC; RFC 5322 <8>:                     Parser API.         (line   41)
* RFC; RFC 5322 <9>:                     email generator Generating MIME documents.
                                                             (line  101)
* RFC; RFC 5322 <10>:                    email generator Generating MIME documents.
                                                             (line  192)
* RFC; RFC 5322 <11>:                    email policy Policy Objects.
                                                             (line  149)
* RFC; RFC 5322 <12>:                    email policy Policy Objects.
                                                             (line  342)
* RFC; RFC 5322 <13>:                    email policy Policy Objects.
                                                             (line  363)
* RFC; RFC 5322 <14>:                    email policy Policy Objects.
                                                             (line  369)
* RFC; RFC 5322 <15>:                    email policy Policy Objects.
                                                             (line  381)
* RFC; RFC 5322 <16>:                    email policy Policy Objects.
                                                             (line  414)
* RFC; RFC 5322 <17>:                    email errors Exception and Defect classes.
                                                             (line   28)
* RFC; RFC 5322 <18>:                    email headerregistry Custom Header Objects.
                                                             (line   16)
* RFC; RFC 5322 <19>:                    email headerregistry Custom Header Objects.
                                                             (line  117)
* RFC; RFC 5322 <20>:                    email headerregistry Custom Header Objects.
                                                             (line  122)
* RFC; RFC 5322 <21>:                    email headerregistry Custom Header Objects.
                                                             (line  123)
* RFC; RFC 5322 <22>:                    email headerregistry Custom Header Objects.
                                                             (line  138)
* RFC; RFC 5322 <23>:                    email headerregistry Custom Header Objects.
                                                             (line  158)
* RFC; RFC 5322 <24>:                    email headerregistry Custom Header Objects.
                                                             (line  415)
* RFC; RFC 5322 <25>:                    email headerregistry Custom Header Objects.
                                                             (line  449)
* RFC; RFC 5322 <26>:                    email headerregistry Custom Header Objects.
                                                             (line  483)
* RFC; RFC 5322 <27>:                    email message Message Representing an email message using the compat32 API.
                                                             (line   21)
* RFC; RFC 5322 <28>:                    Message objects.    (line   17)
* RFC; RFC 5322 <29>:                    http client — HTTP protocol client.
                                                             (line  114)
* RFC; RFC 5322 <30>:                    SMTP Objects.       (line  313)
* RFC; RFC 5322 <31>:                    http server — HTTP servers.
                                                             (line  115)
* RFC; RFC 5424:                         SysLogHandler.      (line   71)
* RFC; RFC 5424 <1>:                     Inserting a BOM into messages sent to a SysLogHandler.
                                                             (line    6)
* RFC; RFC 5424 <2>:                     Inserting a BOM into messages sent to a SysLogHandler.
                                                             (line   19)
* RFC; RFC 5424 <3>:                     Inserting a BOM into messages sent to a SysLogHandler.
                                                             (line   43)
* RFC; RFC 5424 <4>:                     Logging to syslog with RFC5424 support.
                                                             (line    6)
* RFC; RFC 5424 Section 6:               Inserting a BOM into messages sent to a SysLogHandler.
                                                             (line    9)
* RFC; RFC 5735:                         Address objects.    (line  160)
* RFC; RFC 5789:                         HTTP methods.       (line   37)
* RFC; RFC 5842:                         HTTP status codes.  (line   49)
* RFC; RFC 5842 <1>:                     HTTP status codes.  (line  190)
* RFC; RFC 5891:                         encodings idna — Internationalized Domain Names in Applications.
                                                             (line   11)
* RFC; RFC 5894:                         Security<23>.       (line   20)
* RFC; RFC 5895:                         encodings idna — Internationalized Domain Names in Applications.
                                                             (line   11)
* RFC; RFC 5929:                         SSL sockets.        (line  269)
* RFC; RFC 6066:                         Constants<9>.       (line  409)
* RFC; RFC 6066 <1>:                     SSL contexts.       (line  289)
* RFC; RFC 6066 <2>:                     TLS 1 3.            (line   57)
* RFC; RFC 6152:                         smtpd<2>.           (line   15)
* RFC; RFC 6531:                         email<3>.           (line   19)
* RFC; RFC 6531 <1>:                     smtpd<2>.           (line   21)
* RFC; RFC 6531 <2>:                     smtplib<2>.         (line   15)
* RFC; RFC 6531 <3>:                     email message Representing an email message.
                                                             (line  103)
* RFC; RFC 6531 <4>:                     email policy Policy Objects.
                                                             (line  385)
* RFC; RFC 6531 <5>:                     smtplib — SMTP protocol client.
                                                             (line   68)
* RFC; RFC 6532:                         email<3>.           (line   18)
* RFC; RFC 6532 <1>:                     email — An email and MIME handling package.
                                                             (line   14)
* RFC; RFC 6532 <2>:                     email message Representing an email message.
                                                             (line   20)
* RFC; RFC 6532 <3>:                     Parser API.         (line   42)
* RFC; RFC 6532 <4>:                     email policy Policy Objects.
                                                             (line  383)
* RFC; RFC 6585:                         HTTP status codes.  (line  154)
* RFC; RFC 6585 <1>:                     HTTP status codes.  (line  157)
* RFC; RFC 6585 <2>:                     HTTP status codes.  (line  160)
* RFC; RFC 6585 <3>:                     HTTP status codes.  (line  196)
* RFC; RFC 6855:                         imaplib<2>.         (line   12)
* RFC; RFC 6855 <1>:                     imaplib<2>.         (line   14)
* RFC; RFC 6855 <2>:                     IMAP4 Objects.      (line   88)
* RFC; RFC 6855 <3>:                     IMAP4 Objects.      (line   90)
* RFC; RFC 6856:                         poplib<2>.          (line    6)
* RFC; RFC 6856 <1>:                     POP3 Objects.       (line  109)
* RFC; RFC 7159:                         json — JSON encoder and decoder.
                                                             (line   10)
* RFC; RFC 7159 <1>:                     Standard Compliance and Interoperability.
                                                             (line    6)
* RFC; RFC 7159 <2>:                     Top-level Non-Object Non-Array Values.
                                                             (line    9)
* RFC; RFC 7230:                         urllib request — Extensible library for opening URLs.
                                                             (line  203)
* RFC; RFC 7230 <1>:                     HTTPConnection Objects.
                                                             (line  197)
* RFC; RFC 7301:                         Application-Layer Protocol Negotiation Support.
                                                             (line   10)
* RFC; RFC 7301 <1>:                     Constants<9>.       (line  386)
* RFC; RFC 7301 <2>:                     SSL contexts.       (line  257)
* RFC; RFC 7525:                         TLS 1 3.            (line   65)
* RFC; RFC 7538:                         Library<82>.        (line  171)
* RFC; RFC 7693:                         BLAKE2.             (line    6)
* RFC; RFC 7725:                         HTTP status codes.  (line  163)
* RFC; RFC 7914:                         Key derivation.     (line   53)
* RFC; RFC 8089:                         Parsing and generating URIs.
                                                             (line    7)
* RFC; RFC 821:                          smtplib — SMTP protocol client.
                                                             (line   12)
* RFC; RFC 821 <1>:                      smtplib — SMTP protocol client.
                                                             (line  195)
* RFC; RFC 822:                          New and Improved Modules<3>.
                                                             (line   98)
* RFC; RFC 822 <1>:                      Functions<5>.       (line  744)
* RFC; RFC 822 <2>:                      Functions<5>.       (line  747)
* RFC; RFC 822 <3>:                      Functions<5>.       (line  757)
* RFC; RFC 822 <4>:                      Functions<5>.       (line  760)
* RFC; RFC 822 <5>:                      Functions<5>.       (line  774)
* RFC; RFC 822 <6>:                      Functions<5>.       (line  777)
* RFC; RFC 822 <7>:                      email Examples.     (line   36)
* RFC; RFC 822 <8>:                      email header Internationalized headers.
                                                             (line   21)
* RFC; RFC 822 <9>:                      HTTPConnection Objects.
                                                             (line  184)
* RFC; RFC 822 <10>:                     SMTP Objects.       (line   94)
* RFC; RFC 822 <11>:                     SMTP Objects.       (line  228)
* RFC; RFC 822 <12>:                     SMTP Objects.       (line  229)
* RFC; RFC 822 <13>:                     SMTP Example.       (line   10)
* RFC; RFC 822 <14>:                     The GNUTranslations class.
                                                             (line   13)
* RFC; RFC 8297:                         HTTP status codes.  (line   22)
* RFC; RFC 8305:                         Opening network connections.
                                                             (line   77)
* RFC; RFC 8305 <1>:                     Opening network connections.
                                                             (line   86)
* RFC; RFC 8470:                         HTTP status codes.  (line  148)
* RFC; RFC 850:                          Library<15>.        (line  191)
* RFC; RFC 9110:                         Library<15>.        (line  191)
* RFC; RFC 9110 <1>:                     HTTP status codes.  (line   13)
* RFC; RFC 9110 <2>:                     HTTP status codes.  (line   16)
* RFC; RFC 9110 <3>:                     HTTP status codes.  (line   25)
* RFC; RFC 9110 <4>:                     HTTP status codes.  (line   28)
* RFC; RFC 9110 <5>:                     HTTP status codes.  (line   31)
* RFC; RFC 9110 <6>:                     HTTP status codes.  (line   34)
* RFC; RFC 9110 <7>:                     HTTP status codes.  (line   37)
* RFC; RFC 9110 <8>:                     HTTP status codes.  (line   40)
* RFC; RFC 9110 <9>:                     HTTP status codes.  (line   43)
* RFC; RFC 9110 <10>:                    HTTP status codes.  (line   55)
* RFC; RFC 9110 <11>:                    HTTP status codes.  (line   58)
* RFC; RFC 9110 <12>:                    HTTP status codes.  (line   61)
* RFC; RFC 9110 <13>:                    HTTP status codes.  (line   64)
* RFC; RFC 9110 <14>:                    HTTP status codes.  (line   67)
* RFC; RFC 9110 <15>:                    HTTP status codes.  (line   70)
* RFC; RFC 9110 <16>:                    HTTP status codes.  (line   73)
* RFC; RFC 9110 <17>:                    HTTP status codes.  (line   76)
* RFC; RFC 9110 <18>:                    HTTP status codes.  (line   79)
* RFC; RFC 9110 <19>:                    HTTP status codes.  (line   82)
* RFC; RFC 9110 <20>:                    HTTP status codes.  (line   85)
* RFC; RFC 9110 <21>:                    HTTP status codes.  (line   88)
* RFC; RFC 9110 <22>:                    HTTP status codes.  (line   91)
* RFC; RFC 9110 <23>:                    HTTP status codes.  (line   94)
* RFC; RFC 9110 <24>:                    HTTP status codes.  (line   97)
* RFC; RFC 9110 <25>:                    HTTP status codes.  (line  100)
* RFC; RFC 9110 <26>:                    HTTP status codes.  (line  103)
* RFC; RFC 9110 <27>:                    HTTP status codes.  (line  106)
* RFC; RFC 9110 <28>:                    HTTP status codes.  (line  109)
* RFC; RFC 9110 <29>:                    HTTP status codes.  (line  112)
* RFC; RFC 9110 <30>:                    HTTP status codes.  (line  115)
* RFC; RFC 9110 <31>:                    HTTP status codes.  (line  118)
* RFC; RFC 9110 <32>:                    HTTP status codes.  (line  121)
* RFC; RFC 9110 <33>:                    HTTP status codes.  (line  124)
* RFC; RFC 9110 <34>:                    HTTP status codes.  (line  127)
* RFC; RFC 9110 <35>:                    HTTP status codes.  (line  130)
* RFC; RFC 9110 <36>:                    HTTP status codes.  (line  136)
* RFC; RFC 9110 <37>:                    HTTP status codes.  (line  139)
* RFC; RFC 9110 <38>:                    HTTP status codes.  (line  151)
* RFC; RFC 9110 <39>:                    HTTP status codes.  (line  166)
* RFC; RFC 9110 <40>:                    HTTP status codes.  (line  169)
* RFC; RFC 9110 <41>:                    HTTP status codes.  (line  172)
* RFC; RFC 9110 <42>:                    HTTP status codes.  (line  175)
* RFC; RFC 9110 <43>:                    HTTP status codes.  (line  178)
* RFC; RFC 9110 <44>:                    HTTP status codes.  (line  181)
* RFC; RFC 9110 <45>:                    HTTP status category.
                                                             (line   15)
* RFC; RFC 9110 <46>:                    HTTP status category.
                                                             (line   18)
* RFC; RFC 9110 <47>:                    HTTP status category.
                                                             (line   21)
* RFC; RFC 9110 <48>:                    HTTP status category.
                                                             (line   24)
* RFC; RFC 9110 <49>:                    HTTP status category.
                                                             (line   27)
* RFC; RFC 9110 <50>:                    HTTP methods.       (line   13)
* RFC; RFC 9110 <51>:                    HTTP methods.       (line   16)
* RFC; RFC 9110 <52>:                    HTTP methods.       (line   19)
* RFC; RFC 9110 <53>:                    HTTP methods.       (line   22)
* RFC; RFC 9110 <54>:                    HTTP methods.       (line   25)
* RFC; RFC 9110 <55>:                    HTTP methods.       (line   28)
* RFC; RFC 9110 <56>:                    HTTP methods.       (line   31)
* RFC; RFC 9110 <57>:                    HTTP methods.       (line   34)
* RFC; RFC 9239:                         Library<63>.        (line   76)
* RFC; RFC 9562 Section 6.10-3:          Library<8>.         (line  105)
* RFC; RFC 959:                          ftplib — FTP protocol client.
                                                             (line   15)
* rfc2109 (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   71)
* rfc2109_as_netscape (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line   83)
* rfc2965 (http.cookiejar.CookiePolicy attribute): CookiePolicy Objects.
                                                             (line   71)
* rfile (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  117)
* rfile (socketserver.DatagramRequestHandler attribute): Request Handler Objects.
                                                             (line   63)
* rfind() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  214)
* rfind() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  214)
* rfind() (mmap.mmap method):            mmap — Memory-mapped file support.
                                                             (line  284)
* rfind() (str method):                  String Methods<2>.  (line  601)
* rgb_to_hls() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   36)
* rgb_to_hsv() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   44)
* rgb_to_yiq() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   28)
* rglob() (pathlib.Path method):         Reading directories.
                                                             (line   81)
* richcmpfunc (C type):                  Slot Type typedefs. (line   83)
* right (filecmp.dircmp attribute):      The dircmp class.   (line   49)
* right_list (filecmp.dircmp attribute): The dircmp class.   (line   58)
* right_only (filecmp.dircmp attribute): The dircmp class.   (line   71)
* right() (in module turtle):            Turtle motion.      (line   40)
* RIGHTSHIFT (in module token):          token — Constants used with Python parse trees.
                                                             (line  257)
* RIGHTSHIFTEQUAL (in module token):     token — Constants used with Python parse trees.
                                                             (line  290)
* rindex() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line  228)
* rindex() (bytes method):               Bytes and Bytearray Operations.
                                                             (line  228)
* rindex() (str method):                 String Methods<2>.  (line  615)
* rjust() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  344)
* rjust() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  344)
* rjust() (str method):                  String Methods<2>.  (line  631)
* RLIM_INFINITY (in module resource):    Resource Limits.    (line   20)
* RLIMIT_AS (in module resource):        Resource Limits.    (line  148)
* RLIMIT_CORE (in module resource):      Resource Limits.    (line   90)
* RLIMIT_CPU (in module resource):       Resource Limits.    (line   97)
* RLIMIT_DATA (in module resource):      Resource Limits.    (line  109)
* RLIMIT_FSIZE (in module resource):     Resource Limits.    (line  105)
* RLIMIT_KQUEUES (in module resource):   Resource Limits.    (line  224)
* RLIMIT_MEMLOCK (in module resource):   Resource Limits.    (line  137)
* RLIMIT_MSGQUEUE (in module resource):  Resource Limits.    (line  153)
* RLIMIT_NICE (in module resource):      Resource Limits.    (line  161)
* RLIMIT_NOFILE (in module resource):    Resource Limits.    (line  128)
* RLIMIT_NPROC (in module resource):     Resource Limits.    (line  124)
* RLIMIT_NPTS (in module resource):      Resource Limits.    (line  216)
* RLIMIT_OFILE (in module resource):     Resource Limits.    (line  133)
* RLIMIT_RSS (in module resource):       Resource Limits.    (line  119)
* RLIMIT_RTPRIO (in module resource):    Resource Limits.    (line  170)
* RLIMIT_RTTIME (in module resource):    Resource Limits.    (line  178)
* RLIMIT_SBSIZE (in module resource):    Resource Limits.    (line  195)
* RLIMIT_SIGPENDING (in module resource): Resource Limits.   (line  187)
* RLIMIT_STACK (in module resource):     Resource Limits.    (line  113)
* RLIMIT_SWAP (in module resource):      Resource Limits.    (line  205)
* RLIMIT_VMEM (in module resource):      Resource Limits.    (line  141)
* RLock (class in multiprocessing):      Synchronization primitives.
                                                             (line  116)
* RLock (class in threading):            RLock objects.      (line   32)
* RLock() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  203)
* rmd() (ftplib.FTP method):             FTP objects.        (line  347)
* rmdir() (in module os):                Files and Directories.
                                                             (line  824)
* rmdir() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  110)
* rmdir() (pathlib.Path method):         Renaming and deleting.
                                                             (line   61)
* rmtree() (in module shutil):           Directory and files operations.
                                                             (line  268)
* rmtree() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  117)
* RobotFileParser (class in urllib.robotparser): urllib robotparser — Parser for robots txt.
                                                             (line   16)
* robots.txt:                            urllib robotparser — Parser for robots txt.
                                                             (line    8)
* rollback() (sqlite3.Connection method): Connection objects.
                                                             (line   80)
* rollover() (tempfile.SpooledTemporaryFile method): tempfile — Generate temporary files and directories.
                                                             (line  162)
* ROMAN (in module tkinter.font):        tkinter font — Tkinter font wrapper.
                                                             (line   15)
* root (pathlib.PurePath attribute):     Methods and properties.
                                                             (line   31)
* rotate() (collections.deque method):   deque objects.      (line  109)
* rotate() (decimal.Context method):     Context objects.    (line  512)
* rotate() (decimal.Decimal method):     Decimal objects.    (line  527)
* rotate() (logging.handlers.BaseRotatingHandler method): BaseRotatingHandler.
                                                             (line   74)
* RotatingFileHandler (class in logging.handlers): RotatingFileHandler.
                                                             (line    9)
* rotation_filename() (logging.handlers.BaseRotatingHandler method): BaseRotatingHandler.
                                                             (line   57)
* rotator (logging.handlers.BaseRotatingHandler attribute): BaseRotatingHandler.
                                                             (line   49)
* ROUND_05UP (in module decimal):        Rounding modes.     (line   34)
* ROUND_CEILING (in module decimal):     Rounding modes.     (line    6)
* ROUND_DOWN (in module decimal):        Rounding modes.     (line   10)
* ROUND_FLOOR (in module decimal):       Rounding modes.     (line   14)
* ROUND_HALF_DOWN (in module decimal):   Rounding modes.     (line   18)
* ROUND_HALF_EVEN (in module decimal):   Rounding modes.     (line   22)
* ROUND_HALF_UP (in module decimal):     Rounding modes.     (line   26)
* ROUND_UP (in module decimal):          Rounding modes.     (line   30)
* Rounded (class in decimal):            Signals.            (line   79)
* rounding (decimal.Context attribute):  Context objects.    (line  128)
* rounds (sys.float_info attribute):     sys — System-specific parameters and functions.
                                                             (line  673)
* Row (class in sqlite3):                Row objects.        (line    6)
* row_factory (sqlite3.Connection attribute): Connection objects.
                                                             (line  794)
* row_factory (sqlite3.Cursor attribute): Cursor objects.    (line  231)
* rowcount (sqlite3.Cursor attribute):   Cursor objects.     (line  220)
* RPAR (in module token):                token — Constants used with Python parse trees.
                                                             (line  179)
* rpartition() (bytearray method):       Bytes and Bytearray Operations.
                                                             (line  240)
* rpartition() (bytes method):           Bytes and Bytearray Operations.
                                                             (line  240)
* rpartition() (str method):             String Methods<2>.  (line  649)
* rpc_paths (xmlrpc.server.SimpleXMLRPCRequestHandler attribute): SimpleXMLRPCServer objects.
                                                             (line   64)
* rpop() (poplib.POP3 method):           POP3 Objects.       (line   47)
* RS (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line  114)
* rset() (poplib.POP3 method):           POP3 Objects.       (line   75)
* RShift (class in ast):                 Expressions<2>.     (line   53)
* rshift() (in module operator):         operator — Standard operators as functions.
                                                             (line  152)
* rsplit() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line  356)
* rsplit() (bytes method):               Bytes and Bytearray Operations.
                                                             (line  356)
* rsplit() (str method):                 String Methods<2>.  (line  668)
* RSQB (in module token):                token — Constants used with Python parse trees.
                                                             (line  185)
* rstrip() (bytearray method):           Bytes and Bytearray Operations.
                                                             (line  367)
* rstrip() (bytes method):               Bytes and Bytearray Operations.
                                                             (line  367)
* rstrip() (str method):                 String Methods<2>.  (line  677)
* rt() (in module turtle):               Turtle motion.      (line   40)
* RTLD_DEEPBIND (in module os):          Miscellaneous System Information.
                                                             (line  163)
* RTLD_GLOBAL (in module os):            Miscellaneous System Information.
                                                             (line  163)
* RTLD_LAZY (in module os):              Miscellaneous System Information.
                                                             (line  163)
* RTLD_LOCAL (in module os):             Miscellaneous System Information.
                                                             (line  163)
* RTLD_NODELETE (in module os):          Miscellaneous System Information.
                                                             (line  163)
* RTLD_NOLOAD (in module os):            Miscellaneous System Information.
                                                             (line  163)
* RTLD_NOW (in module os):               Miscellaneous System Information.
                                                             (line  163)
* ruler (cmd.Cmd attribute):             Cmd Objects.        (line  171)
* run (pdb command):                     Debugger commands.  (line  415)
* Run script:                            Format menu Editor window only.
                                                             (line   53)
* run_coroutine_threadsafe() (in module asyncio): Scheduling from other threads.
                                                             (line    6)
* run_docstring_examples() (in module doctest): Basic API.   (line  127)
* run_forever() (asyncio.loop method):   Running and stopping the loop.
                                                             (line   16)
* run_in_executor() (asyncio.loop method): Executing code in thread or process pools.
                                                             (line    6)
* run_in_subinterp() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  663)
* run_module() (in module runpy):        runpy — Locating and executing Python modules.
                                                             (line   26)
* run_path() (in module runpy):          runpy — Locating and executing Python modules.
                                                             (line   97)
* run_python_until_end() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   30)
* run_script() (modulefinder.ModuleFinder method): modulefinder — Find modules used by a script.
                                                             (line   44)
* run_until_complete() (asyncio.loop method): Running and stopping the loop.
                                                             (line    6)
* run_with_locale() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  466)
* run_with_tz() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  474)
* run() (asyncio.Runner method):         Runner context manager.
                                                             (line   36)
* run() (bdb.Bdb method):                bdb — Debugger framework.
                                                             (line  426)
* run() (contextvars.Context method):    Manual Context Management.
                                                             (line   64)
* run() (doctest.DocTestRunner method):  DocTestRunner objects.
                                                             (line  100)
* run() (in module asyncio):             Running an asyncio Program.
                                                             (line    6)
* run() (in module pdb):                 Command-line interface<6>.
                                                             (line   68)
* run() (in module profile):             profile and cProfile Module Reference.
                                                             (line    9)
* run() (in module subprocess):          Using the subprocess Module.
                                                             (line   11)
* run() (multiprocessing.Process method): Process and exceptions.
                                                             (line   68)
* run() (pdb.Pdb method):                Command-line interface<6>.
                                                             (line  160)
* run() (profile.Profile method):        profile and cProfile Module Reference.
                                                             (line  108)
* run() (sched.scheduler method):        Scheduler Objects.  (line   51)
* run() (threading.Thread method):       Thread objects.     (line  103)
* run() (trace.Trace method):            Programmatic Interface.
                                                             (line   22)
* run() (unittest.IsolatedAsyncioTestCase method): Test cases.
                                                             (line  898)
* run() (unittest.TestCase method):      Test cases.         (line   81)
* run() (unittest.TestSuite method):     Grouping tests.     (line   39)
* run() (unittest.TextTestRunner method): Loading and running tests.
                                                             (line  503)
* run() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line   98)
* runcall() (bdb.Bdb method):            bdb — Debugger framework.
                                                             (line  443)
* runcall() (in module pdb):             Command-line interface<6>.
                                                             (line   87)
* runcall() (pdb.Pdb method):            Command-line interface<6>.
                                                             (line  160)
* runcall() (profile.Profile method):    profile and cProfile Module Reference.
                                                             (line  117)
* runcode() (code.InteractiveInterpreter method): Interactive Interpreter Objects.
                                                             (line   33)
* runctx() (bdb.Bdb method):             bdb — Debugger framework.
                                                             (line  438)
* runctx() (in module profile):          profile and cProfile Module Reference.
                                                             (line   23)
* runctx() (profile.Profile method):     profile and cProfile Module Reference.
                                                             (line  112)
* runctx() (trace.Trace method):         Programmatic Interface.
                                                             (line   28)
* runeval() (bdb.Bdb method):            bdb — Debugger framework.
                                                             (line  432)
* runeval() (in module pdb):             Command-line interface<6>.
                                                             (line   80)
* runeval() (pdb.Pdb method):            Command-line interface<6>.
                                                             (line  160)
* runfunc() (trace.Trace method):        Programmatic Interface.
                                                             (line   35)
* Runner (class in asyncio):             Runner context manager.
                                                             (line    6)
* running() (concurrent.futures.Future method): Future Objects.
                                                             (line   27)
* runsource() (code.InteractiveInterpreter method): Interactive Interpreter Objects.
                                                             (line    6)
* runtime (sys._emscripten_info attribute): sys — System-specific parameters and functions.
                                                             (line  354)
* runtime_checkable() (in module typing): Other special directives.
                                                             (line  181)
* RuntimeError:                          Concrete exceptions.
                                                             (line  260)
* RuntimeWarning:                        Warnings.           (line   51)
* RUSAGE_BOTH (in module resource):      Resource Usage.     (line  122)
* RUSAGE_CHILDREN (in module resource):  Resource Usage.     (line  116)
* RUSAGE_SELF (in module resource):      Resource Usage.     (line  110)
* RUSAGE_THREAD (in module resource):    Resource Usage.     (line  128)
* RWF_APPEND (in module os):             File Descriptor Operations.
                                                             (line  716)
* RWF_DSYNC (in module os):              File Descriptor Operations.
                                                             (line  696)
* RWF_HIPRI (in module os):              File Descriptor Operations.
                                                             (line  626)
* RWF_NOWAIT (in module os):             File Descriptor Operations.
                                                             (line  611)
* RWF_SYNC (in module os):               File Descriptor Operations.
                                                             (line  706)
* S (in module re):                      Flags.              (line  108)
* S_ENFMT (in module stat):              stat — Interpreting stat results.
                                                             (line  317)
* S_IEXEC (in module stat):              stat — Interpreting stat results.
                                                             (line  331)
* S_IFBLK (in module stat):              stat — Interpreting stat results.
                                                             (line  206)
* S_IFCHR (in module stat):              stat — Interpreting stat results.
                                                             (line  214)
* S_IFDIR (in module stat):              stat — Interpreting stat results.
                                                             (line  210)
* S_IFDOOR (in module stat):             stat — Interpreting stat results.
                                                             (line  222)
* S_IFIFO (in module stat):              stat — Interpreting stat results.
                                                             (line  218)
* S_IFLNK (in module stat):              stat — Interpreting stat results.
                                                             (line  198)
* S_IFMT() (in module stat):             stat — Interpreting stat results.
                                                             (line   78)
* S_IFPORT (in module stat):             stat — Interpreting stat results.
                                                             (line  228)
* S_IFREG (in module stat):              stat — Interpreting stat results.
                                                             (line  202)
* S_IFSOCK (in module stat):             stat — Interpreting stat results.
                                                             (line  194)
* S_IFWHT (in module stat):              stat — Interpreting stat results.
                                                             (line  234)
* S_IMODE() (in module stat):            stat — Interpreting stat results.
                                                             (line   71)
* S_IREAD (in module stat):              stat — Interpreting stat results.
                                                             (line  323)
* S_IRGRP (in module stat):              stat — Interpreting stat results.
                                                             (line  289)
* S_IROTH (in module stat):              stat — Interpreting stat results.
                                                             (line  305)
* S_IRUSR (in module stat):              stat — Interpreting stat results.
                                                             (line  273)
* S_IRWXG (in module stat):              stat — Interpreting stat results.
                                                             (line  285)
* S_IRWXO (in module stat):              stat — Interpreting stat results.
                                                             (line  301)
* S_IRWXU (in module stat):              stat — Interpreting stat results.
                                                             (line  269)
* S_ISBLK() (in module stat):            stat — Interpreting stat results.
                                                             (line   30)
* S_ISCHR() (in module stat):            stat — Interpreting stat results.
                                                             (line   25)
* S_ISDIR() (in module stat):            stat — Interpreting stat results.
                                                             (line   21)
* S_ISDOOR() (in module stat):           stat — Interpreting stat results.
                                                             (line   50)
* S_ISFIFO() (in module stat):           stat — Interpreting stat results.
                                                             (line   38)
* S_ISGID (in module stat):              stat — Interpreting stat results.
                                                             (line  251)
* S_ISLNK() (in module stat):            stat — Interpreting stat results.
                                                             (line   42)
* S_ISPORT() (in module stat):           stat — Interpreting stat results.
                                                             (line   56)
* S_ISREG() (in module stat):            stat — Interpreting stat results.
                                                             (line   34)
* S_ISSOCK() (in module stat):           stat — Interpreting stat results.
                                                             (line   46)
* S_ISUID (in module stat):              stat — Interpreting stat results.
                                                             (line  247)
* S_ISVTX (in module stat):              stat — Interpreting stat results.
                                                             (line  262)
* S_ISWHT() (in module stat):            stat — Interpreting stat results.
                                                             (line   62)
* S_IWGRP (in module stat):              stat — Interpreting stat results.
                                                             (line  293)
* S_IWOTH (in module stat):              stat — Interpreting stat results.
                                                             (line  309)
* S_IWRITE (in module stat):             stat — Interpreting stat results.
                                                             (line  327)
* S_IWUSR (in module stat):              stat — Interpreting stat results.
                                                             (line  277)
* S_IXGRP (in module stat):              stat — Interpreting stat results.
                                                             (line  297)
* S_IXOTH (in module stat):              stat — Interpreting stat results.
                                                             (line  313)
* S_IXUSR (in module stat):              stat — Interpreting stat results.
                                                             (line  281)
* safe (uuid.SafeUUID attribute):        uuid — UUID objects according to RFC 4122.
                                                             (line   33)
* safe_path (sys.flags attribute):       sys — System-specific parameters and functions.
                                                             (line  573)
* safe_substitute() (string.Template method): Template strings.
                                                             (line   50)
* SafeChildWatcher (class in asyncio):   Process Watchers.   (line  126)
* saferepr() (in module pprint):         Functions<4>.       (line  100)
* SafeUUID (class in uuid):              uuid — UUID objects according to RFC 4122.
                                                             (line   29)
* same_files (filecmp.dircmp attribute): The dircmp class.   (line   89)
* same_quantum() (decimal.Context method): Context objects.  (line  516)
* same_quantum() (decimal.Decimal method): Decimal objects.  (line  539)
* samefile() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  448)
* samefile() (pathlib.Path method):      Querying file type and status.
                                                             (line  145)
* SameFileError:                         Directory and files operations.
                                                             (line   59)
* sameopenfile() (in module os.path):    os path — Common pathname manipulations.
                                                             (line  462)
* samesite (http.cookies.Morsel attribute): Morsel Objects.  (line   13)
* samestat() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  471)
* sample() (in module random):           Functions for sequences.
                                                             (line   69)
* samples() (statistics.NormalDist method): NormalDist objects.
                                                             (line   58)
* SATURDAY (in module calendar):         calendar — General calendar-related functions.
                                                             (line  445)
* save() (http.cookiejar.FileCookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line  106)
* save() (test.support.SaveSignals method): test support — Utilities for the Python test suite.
                                                             (line  774)
* SaveAs (class in tkinter.filedialog):  Native Load/Save Dialogs.
                                                             (line   60)
* SAVEDCWD (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   14)
* SaveFileDialog (class in tkinter.filedialog): Native Load/Save Dialogs.
                                                             (line  145)
* SaveKey() (in module winreg):          Functions<13>.      (line  394)
* SaveSignals (class in test.support):   test support — Utilities for the Python test suite.
                                                             (line  769)
* savetty() (in module curses):          Functions<6>.       (line  442)
* SAX2DOM (class in xml.dom.pulldom):    xml dom pulldom — Support for building partial DOM trees.
                                                             (line   80)
* SAXException:                          xml sax — Support for SAX2 parsers.
                                                             (line   85)
* SAXNotRecognizedException:             xml sax — Support for SAX2 parsers.
                                                             (line  110)
* SAXNotSupportedException:              xml sax — Support for SAX2 parsers.
                                                             (line  117)
* SAXParseException:                     xml sax — Support for SAX2 parsers.
                                                             (line  102)
* scaleb() (decimal.Context method):     Context objects.    (line  520)
* scaleb() (decimal.Decimal method):     Decimal objects.    (line  549)
* scandir() (in module os):              Files and Directories.
                                                             (line  841)
* scanf (C function):                    Simulating scanf.   (line    6)
* SCHED_BATCH (in module os):            Interface to the scheduler.
                                                             (line   19)
* SCHED_FIFO (in module os):             Interface to the scheduler.
                                                             (line   32)
* sched_get_priority_max() (in module os): Interface to the scheduler.
                                                             (line   63)
* sched_get_priority_min() (in module os): Interface to the scheduler.
                                                             (line   58)
* sched_getaffinity() (in module os):    Interface to the scheduler.
                                                             (line  110)
* sched_getparam() (in module os):       Interface to the scheduler.
                                                             (line   87)
* sched_getscheduler() (in module os):   Interface to the scheduler.
                                                             (line   75)
* SCHED_IDLE (in module os):             Interface to the scheduler.
                                                             (line   24)
* SCHED_OTHER (in module os):            Interface to the scheduler.
                                                             (line   15)
* sched_param (class in os):             Interface to the scheduler.
                                                             (line   46)
* sched_priority (os.sched_param attribute): Interface to the scheduler.
                                                             (line   54)
* SCHED_RESET_ON_FORK (in module os):    Interface to the scheduler.
                                                             (line   40)
* SCHED_RR (in module os):               Interface to the scheduler.
                                                             (line   36)
* sched_rr_get_interval() (in module os): Interface to the scheduler.
                                                             (line   93)
* sched_setaffinity() (in module os):    Interface to the scheduler.
                                                             (line  103)
* sched_setparam() (in module os):       Interface to the scheduler.
                                                             (line   81)
* sched_setscheduler() (in module os):   Interface to the scheduler.
                                                             (line   68)
* SCHED_SPORADIC (in module os):         Interface to the scheduler.
                                                             (line   28)
* sched_yield() (in module os):          Interface to the scheduler.
                                                             (line   98)
* scheduler (class in sched):            sched — Event scheduler.
                                                             (line   13)
* SCM_CREDS2 (in module socket):         Constants<8>.       (line  321)
* scope:                                 Naming and binding. (line    6)
* scope <1>:                             Resolution of names.
                                                             (line    6)
* scope_id (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  306)
* Screen (class in turtle):              Public classes.     (line   30)
* screensize() (in module turtle):       Window control.     (line   90)
* script_from_examples() (in module doctest): Debugging.     (line   72)
* scroll() (curses.window method):       Window Objects.     (line  501)
* ScrolledCanvas (class in turtle):      Public classes.     (line   34)
* ScrolledText (class in tkinter.scrolledtext): tkinter scrolledtext — Scrolled Text Widget.
                                                             (line   24)
* scrollok() (curses.window method):     Window Objects.     (line  505)
* scrypt() (in module hashlib):          Key derivation.     (line   49)
* seal() (in module unittest.mock):      Sealing mocks.      (line    6)
* search_function() (in module encodings): encodings — Encodings package.
                                                             (line   23)
* search() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  226)
* search() (in module re):               Functions<2>.       (line   36)
* search() (re.Pattern method):          Regular Expression Objects.
                                                             (line   15)
* second (datetime.datetime attribute):  datetime Objects.   (line  325)
* second (datetime.time attribute):      time Objects.       (line   58)
* seconds (datetime.timedelta attribute): timedelta Objects. (line  119)
* seconds since the epoch:               time — Time access and conversions.
                                                             (line   24)
* SECTCRE (configparser.ConfigParser attribute): Customizing Parser Behaviour.
                                                             (line  300)
* sections() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  116)
* secure (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   48)
* secure (http.cookies.Morsel attribute): Morsel Objects.    (line   13)
* secure hash algorithm, SHA1, SHA2, SHA224, SHA256, SHA384, SHA512, SHA3, Shake, Blake2: hashlib — Secure hashes and message digests.
                                                             (line    8)
* Secure Sockets Layer:                  ssl — TLS/SSL wrapper for socket objects.
                                                             (line    8)
* security considerations:               xdrlib — Encode and decode XDR data.
                                                             (line   15)
* security_level (ssl.SSLContext attribute): SSL contexts.   (line  624)
* see() (tkinter.ttk.Treeview method):   ttk Treeview.       (line  241)
* seed_bits (sys.hash_info attribute):   sys — System-specific parameters and functions.
                                                             (line 1062)
* seed() (in module random):             Bookkeeping functions.
                                                             (line    6)
* seed() (random.Random method):         Alternative Generator.
                                                             (line   18)
* SEEK_CUR (in module os):               File Descriptor Operations.
                                                             (line  326)
* SEEK_DATA (in module os):              File Descriptor Operations.
                                                             (line  350)
* SEEK_END (in module os):               File Descriptor Operations.
                                                             (line  326)
* SEEK_HOLE (in module os):              File Descriptor Operations.
                                                             (line  350)
* SEEK_SET (in module os):               File Descriptor Operations.
                                                             (line  326)
* seek() (io.IOBase method):             I/O Base Classes.   (line  105)
* seek() (io.TextIOBase method):         Text I/O<2>.        (line   65)
* seek() (io.TextIOWrapper method):      Text I/O<2>.        (line  204)
* seek() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  294)
* seek() (sqlite3.Blob method):          Blob objects.       (line   63)
* seekable() (bz2.BZ2File method):       De compression of files.
                                                             (line   98)
* seekable() (io.IOBase method):         I/O Base Classes.   (line  128)
* seekable() (mmap.mmap method):         mmap — Memory-mapped file support.
                                                             (line  305)
* select() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  243)
* select() (in module select):           select — Waiting for I/O completion.
                                                             (line  115)
* select() (selectors.BaseSelector method): Classes<4>.      (line  108)
* select() (tkinter.ttk.Notebook method): ttk Notebook.      (line   53)
* selected_alpn_protocol() (ssl.SSLSocket method): SSL sockets.
                                                             (line  275)
* selected_npn_protocol() (ssl.SSLSocket method): SSL sockets.
                                                             (line  285)
* selection_add() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  264)
* selection_remove() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  271)
* selection_set() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  257)
* selection_toggle() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  278)
* selection() (tkinter.ttk.Treeview method): ttk Treeview.   (line  249)
* selector (urllib.request.Request attribute): Request Objects.
                                                             (line   34)
* SelectorEventLoop (class in asyncio):  Event loop implementations.
                                                             (line   11)
* SelectorKey (class in selectors):      Classes<4>.         (line   29)
* SelectSelector (class in selectors):   Classes<4>.         (line  167)
* Self (in module typing):               Special types.      (line  138)
* Semaphore (class in asyncio):          Semaphore.          (line    6)
* Semaphore (class in multiprocessing):  Synchronization primitives.
                                                             (line  184)
* Semaphore (class in threading):        Semaphore objects.  (line   19)
* Semaphore() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  208)
* semaphores, binary:                    _thread — Low-level threading API.
                                                             (line    6)
* SEMI (in module token):                token — Constants used with Python parse trees.
                                                             (line  194)
* SEND (opcode):                         Python Bytecode Instructions.
                                                             (line 1261)
* send_bytes() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   54)
* send_error() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  214)
* send_fds() (in module socket):         Other functions<2>. (line  459)
* send_header() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  250)
* send_message() (smtplib.SMTP method):  SMTP Objects.       (line  303)
* send_response_only() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  265)
* send_response() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  234)
* send_signal() (asyncio.subprocess.Process method): Interacting with Subprocesses.
                                                             (line   86)
* send_signal() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   44)
* send_signal() (subprocess.Popen method): Popen Objects.    (line   82)
* send() (coroutine method):             Coroutine Objects.  (line   23)
* send() (generator method):             Generator-iterator methods.
                                                             (line   26)
* send() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  216)
* send() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  250)
* send() (logging.handlers.DatagramHandler method): DatagramHandler.
                                                             (line   43)
* send() (logging.handlers.SocketHandler method): SocketHandler.
                                                             (line   63)
* send() (multiprocessing.connection.Connection method): Connection Objects.
                                                             (line   15)
* send() (socket.socket method):         Socket Objects.     (line  394)
* sendall() (socket.socket method):      Socket Objects.     (line  409)
* sendcmd() (ftplib.FTP method):         FTP objects.        (line  156)
* sendfile() (asyncio.loop method):      Transferring files. (line    6)
* sendfile() (in module os):             File Descriptor Operations.
                                                             (line  752)
* sendfile() (socket.socket method):     Socket Objects.     (line  502)
* sendfile() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  279)
* SendfileNotAvailableError:             Exceptions<13>.     (line   36)
* sendfunc (C type):                     Slot Type typedefs. (line  116)
* sendmail() (smtplib.SMTP method):      SMTP Objects.       (line  225)
* sendmsg_afalg() (socket.socket method): Socket Objects.    (line  491)
* sendmsg() (socket.socket method):      Socket Objects.     (line  447)
* sendto() (asyncio.DatagramTransport method): Datagram Transports.
                                                             (line    6)
* sendto() (socket.socket method):       Socket Objects.     (line  428)
* sentinel (in module unittest.mock):    sentinel.           (line    6)
* sentinel (multiprocessing.Process attribute): Process and exceptions.
                                                             (line  188)
* sep (in module os):                    Miscellaneous System Information.
                                                             (line  115)
* SEPTEMBER (in module calendar):        calendar — General calendar-related functions.
                                                             (line  488)
* sequence:                              Glossary.           (line 1515)
* Sequence (class in collections.abc):   Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   67)
* Sequence (class in typing):            Aliases to container ABCs in collections abc.
                                                             (line  112)
* sequence; item:                        Subscriptions.      (line    6)
* sequence; iteration:                   Iterator Types.     (line    6)
* SequenceMatcher (class in difflib):    SequenceMatcher objects.
                                                             (line    8)
* serialize() (sqlite3.Connection method): Connection objects.
                                                             (line  676)
* serializing; objects:                  pickle — Python object serialization.
                                                             (line    8)
* serve_forever() (asyncio.Server method): Server objects.   (line   91)
* serve_forever() (socketserver.BaseServer method): Server Objects.
                                                             (line   32)
* Server (class in asyncio):             Server objects.     (line   12)
* server (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line   75)
* server (socketserver.BaseRequestHandler attribute): Request Handler Objects.
                                                             (line   52)
* server_activate() (socketserver.BaseServer method): Server Objects.
                                                             (line  167)
* server_address (socketserver.BaseServer attribute): Server Objects.
                                                             (line   79)
* server_bind() (socketserver.BaseServer method): Server Objects.
                                                             (line  173)
* server_close() (socketserver.BaseServer method): Server Objects.
                                                             (line   61)
* server_hostname (ssl.SSLSocket attribute): SSL sockets.    (line  355)
* server_side (ssl.SSLSocket attribute): SSL sockets.        (line  348)
* server_software (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  177)
* server_version (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  134)
* server_version (http.server.SimpleHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  362)
* ServerProxy (class in xmlrpc.client):  xmlrpc client — XML-RPC client access.
                                                             (line   29)
* service_actions() (socketserver.BaseServer method): Server Objects.
                                                             (line   45)
* session (ssl.SSLSocket attribute):     SSL sockets.        (line  368)
* session_reused (ssl.SSLSocket attribute): SSL sockets.     (line  378)
* session_stats() (ssl.SSLContext method): SSL contexts.     (line  479)
* set (built-in class):                  Set Types — set frozenset.
                                                             (line   33)
* Set (class in ast):                    Literals<3>.        (line   91)
* Set (class in collections.abc):        Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  114)
* Set (class in typing):                 Aliases to built-in types.
                                                             (line   30)
* Set Breakpoint:                        Help menu Shell and Editor.
                                                             (line   30)
* set comprehension:                     Glossary.           (line 1536)
* SET_ADD (opcode):                      Python Bytecode Instructions.
                                                             (line  372)
* set_all():                             Reference Count Details.
                                                             (line   98)
* set_allowed_domains() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   70)
* set_alpn_protocols() (ssl.SSLContext method): SSL contexts.
                                                             (line  251)
* set_app() (wsgiref.simple_server.WSGIServer method): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   63)
* set_asyncgen_hooks() (in module sys):  sys — System-specific parameters and functions.
                                                             (line 1703)
* set_authorizer() (sqlite3.Connection method): Connection objects.
                                                             (line  345)
* set_auto_history() (in module readline): History list.     (line   43)
* set_blocked_domains() (http.cookiejar.DefaultCookiePolicy method): DefaultCookiePolicy Objects.
                                                             (line   56)
* set_blocking() (in module os):         File Descriptor Operations.
                                                             (line  813)
* set_boundary() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  411)
* set_boundary() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  588)
* set_break() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  339)
* set_charset() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  235)
* set_child_watcher() (asyncio.AbstractEventLoopPolicy method): Policy Objects.
                                                             (line   44)
* set_child_watcher() (in module asyncio): Process Watchers. (line   31)
* set_children() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line   25)
* set_ciphers() (ssl.SSLContext method): SSL contexts.       (line  238)
* set_completer_delims() (in module readline): Completion.   (line   50)
* set_completer() (in module readline):  Completion.         (line   14)
* set_completion_display_matches_hook() (in module readline): Completion.
                                                             (line   59)
* set_content() (email.contentmanager.ContentManager method): email contentmanager Managing MIME Content.
                                                             (line   40)
* set_content() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  590)
* set_content() (in module email.contentmanager): Content Manager Instances.
                                                             (line   35)
* set_continue() (bdb.Bdb method):       bdb — Debugger framework.
                                                             (line  324)
* set_cookie_if_ok() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   69)
* set_cookie() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   73)
* set_coroutine_origin_tracking_depth() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1728)
* set_data() (importlib.abc.SourceLoader method): importlib abc – Abstract base classes related to import.
                                                             (line  386)
* set_data() (importlib.machinery.SourceFileLoader method): importlib machinery – Importers and path hooks.
                                                             (line  230)
* set_date() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   97)
* set_debug() (asyncio.loop method):     Enabling debug mode.
                                                             (line   14)
* set_debug() (in module gc):            gc — Garbage Collector interface.
                                                             (line   51)
* set_debuglevel() (ftplib.FTP method):  FTP objects.        (line   73)
* set_debuglevel() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line   93)
* set_debuglevel() (poplib.POP3 method): POP3 Objects.       (line   11)
* set_debuglevel() (smtplib.SMTP method): SMTP Objects.      (line    8)
* set_default_executor() (asyncio.loop method): Executing code in thread or process pools.
                                                             (line   76)
* set_default_type() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  342)
* set_default_type() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  450)
* set_default_verify_paths() (ssl.SSLContext method): SSL contexts.
                                                             (line  229)
* set_defaults() (argparse.ArgumentParser method): Parser defaults.
                                                             (line    6)
* set_defaults() (optparse.OptionParser method): Other methods.
                                                             (line   27)
* set_ecdh_curve() (ssl.SSLContext method): SSL contexts.    (line  365)
* set_errno() (in module ctypes):        Utility functions.  (line  203)
* set_error_mode() (in module msvcrt):   Other Functions.    (line   12)
* set_escdelay() (in module curses):     Functions<6>.       (line  453)
* set_event_loop_policy() (in module asyncio): Getting and Setting the Policy.
                                                             (line   13)
* set_event_loop() (asyncio.AbstractEventLoopPolicy method): Policy Objects.
                                                             (line   23)
* set_event_loop() (in module asyncio):  Event loop.         (line   63)
* set_events() (in module sys.monitoring): Setting events globally.
                                                             (line   13)
* set_exception_handler() (asyncio.loop method): Error handling API.
                                                             (line    8)
* set_exception() (asyncio.Future method): Future Object.    (line   56)
* set_exception() (concurrent.futures.Future method): Future Objects.
                                                             (line  117)
* set_executable() (in module multiprocessing): Miscellaneous<3>.
                                                             (line  117)
* set_filter() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  127)
* set_flags() (mailbox.Maildir method):  Maildir objects.    (line  110)
* set_flags() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   72)
* set_flags() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   72)
* set_flags() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   71)
* set_forkserver_preload() (in module multiprocessing): Miscellaneous<3>.
                                                             (line  132)
* set_from() (mailbox.mboxMessage method): mboxMessage objects.
                                                             (line   53)
* set_from() (mailbox.MMDFMessage method): MMDFMessage objects.
                                                             (line   52)
* SET_FUNCTION_ATTRIBUTE (opcode):       Python Bytecode Instructions.
                                                             (line 1123)
* set_handle_inheritable() (in module os): Inheritance of File Descriptors.
                                                             (line   42)
* set_history_length() (in module readline): History file.   (line   30)
* set_info() (mailbox.Maildir method):   Maildir objects.    (line  172)
* set_info() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line  108)
* set_inheritable() (in module os):      Inheritance of File Descriptors.
                                                             (line   32)
* set_inheritable() (socket.socket method): Socket Objects.  (line  519)
* set_int_max_str_digits() (in module sys): sys — System-specific parameters and functions.
                                                             (line 1506)
* set_labels() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   51)
* set_last_error() (in module ctypes):   Utility functions.  (line  212)
* set_local_events() (in module sys.monitoring): Per code object events.
                                                             (line   16)
* set_memlimit() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  307)
* set_name() (asyncio.Task method):      Task object.        (line  187)
* set_next() (bdb.Bdb method):           bdb — Debugger framework.
                                                             (line  302)
* set_nonstandard_attr() (http.cookiejar.Cookie method): Cookie Objects<2>.
                                                             (line  105)
* set_npn_protocols() (ssl.SSLContext method): SSL contexts. (line  266)
* set_ok() (http.cookiejar.CookiePolicy method): CookiePolicy Objects.
                                                             (line    9)
* set_param() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  351)
* set_param() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  518)
* set_pasv() (ftplib.FTP method):        FTP objects.        (line  212)
* set_payload() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  224)
* set_policy() (http.cookiejar.CookieJar method): CookieJar and FileCookieJar Objects.
                                                             (line   57)
* set_pre_input_hook() (in module readline): Startup hooks.  (line   14)
* set_progress_handler() (sqlite3.Connection method): Connection objects.
                                                             (line  378)
* set_protocol() (asyncio.BaseTransport method): Base Transport.
                                                             (line   81)
* set_proxy() (urllib.request.Request method): Request Objects.
                                                             (line  114)
* set_psk_client_callback() (ssl.SSLContext method): SSL contexts.
                                                             (line  659)
* set_psk_server_callback() (ssl.SSLContext method): SSL contexts.
                                                             (line  711)
* set_quit() (bdb.Bdb method):           bdb — Debugger framework.
                                                             (line  329)
* set_result() (asyncio.Future method):  Future Object.      (line   49)
* set_result() (concurrent.futures.Future method): Future Objects.
                                                             (line  105)
* set_return() (bdb.Bdb method):         bdb — Debugger framework.
                                                             (line  306)
* set_running_or_notify_cancel() (concurrent.futures.Future method): Future Objects.
                                                             (line   85)
* set_selection() (tkinter.filedialog.FileDialog method): Native Load/Save Dialogs.
                                                             (line  131)
* set_seq1() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line   54)
* set_seq2() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line   59)
* set_seqs() (difflib.SequenceMatcher method): SequenceMatcher objects.
                                                             (line   44)
* set_sequences() (mailbox.MH method):   MH objects.         (line   61)
* set_sequences() (mailbox.MHMessage method): MHMessage objects.
                                                             (line   37)
* set_server_documentation() (xmlrpc.server.DocCGIXMLRPCRequestHandler method): DocCGIXMLRPCRequestHandler.
                                                             (line   24)
* set_server_documentation() (xmlrpc.server.DocXMLRPCServer method): DocXMLRPCServer objects.
                                                             (line   24)
* set_server_name() (xmlrpc.server.DocCGIXMLRPCRequestHandler method): DocCGIXMLRPCRequestHandler.
                                                             (line   18)
* set_server_name() (xmlrpc.server.DocXMLRPCServer method): DocXMLRPCServer objects.
                                                             (line   18)
* set_server_title() (xmlrpc.server.DocCGIXMLRPCRequestHandler method): DocCGIXMLRPCRequestHandler.
                                                             (line   13)
* set_server_title() (xmlrpc.server.DocXMLRPCServer method): DocXMLRPCServer objects.
                                                             (line   13)
* set_servername_callback() (ssl.SSLContext method): SSL contexts.
                                                             (line  337)
* set_start_method() (in module multiprocessing): Miscellaneous<3>.
                                                             (line  149)
* set_startup_hook() (in module readline): Startup hooks.    (line    6)
* set_step() (bdb.Bdb method):           bdb — Debugger framework.
                                                             (line  298)
* set_subdir() (mailbox.MaildirMessage method): MaildirMessage objects.
                                                             (line   58)
* set_tabsize() (in module curses):      Functions<6>.       (line  468)
* set_task_factory() (asyncio.loop method): Creating futures and tasks.
                                                             (line   51)
* set_threshold() (in module gc):        gc — Garbage Collector interface.
                                                             (line   92)
* set_trace_callback() (sqlite3.Connection method): Connection objects.
                                                             (line  396)
* set_trace() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  315)
* set_trace() (in module bdb):           bdb — Debugger framework.
                                                             (line  476)
* set_trace() (in module pdb):           Command-line interface<6>.
                                                             (line   94)
* set_trace() (pdb.Pdb method):          Command-line interface<6>.
                                                             (line  160)
* set_tunnel() (http.client.HTTPConnection method): HTTPConnection Objects.
                                                             (line  103)
* set_type() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  551)
* set_unittest_reportflags() (in module doctest): Unittest API.
                                                             (line  168)
* set_unixfrom() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  146)
* set_unixfrom() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  157)
* set_until() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  310)
* SET_UPDATE (opcode):                   Python Bytecode Instructions.
                                                             (line  720)
* set_url() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   21)
* set_usage() (optparse.OptionParser method): Other methods. (line    8)
* set_userptr() (curses.panel.Panel method): Panel Objects.  (line   43)
* set_visible() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   68)
* set_wakeup_fd() (in module signal):    Module contents<3>. (line  473)
* set_write_buffer_limits() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   33)
* set; comprehensions:                   Set displays.       (line    6)
* set; display:                          Set displays.       (line    6)
* set() (asyncio.Event method):          Event.              (line   51)
* set() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  285)
* set() (configparser.RawConfigParser method): RawConfigParser Objects.
                                                             (line   48)
* set() (contextvars.ContextVar method): Context Variables.  (line   46)
* set() (http.cookies.Morsel method):    Morsel Objects.     (line   61)
* set() (test.support.os_helper.EnvironmentVarGuard method): test support os_helper — Utilities for os tests.
                                                             (line   65)
* set() (threading.Event method):        Event objects.      (line   30)
* set() (tkinter.ttk.Combobox method):   ttk Combobox.       (line   19)
* set() (tkinter.ttk.Spinbox method):    ttk Spinbox.        (line   12)
* set() (tkinter.ttk.Treeview method):   ttk Treeview.       (line  285)
* set() (xml.etree.ElementTree.Element method): Element Objects.
                                                             (line   81)
* setacl() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  257)
* SetAllocTrackerActivationThreshold() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  120)
* SetAllocTrackerMaximumAmplification() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  135)
* setannotation() (imaplib.IMAP4 method): IMAP4 Objects.     (line  262)
* setattrfunc (C type):                  Slot Type typedefs. (line   48)
* setAttribute() (xml.dom.Element method): Element Objects<2>.
                                                             (line   67)
* setAttributeNode() (xml.dom.Element method): Element Objects<2>.
                                                             (line   71)
* setAttributeNodeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   79)
* setAttributeNS() (xml.dom.Element method): Element Objects<2>.
                                                             (line   87)
* setattrofunc (C type):                 Slot Type typedefs. (line   61)
* SetBase() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   22)
* setblocking() (socket.socket method):  Socket Objects.     (line  526)
* setByteStream() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   36)
* setcbreak() (in module tty):           tty — Terminal control functions.
                                                             (line   54)
* setCharacterStream() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   55)
* SetComp (class in ast):                Comprehensions.     (line    6)
* setcomptype() (wave.Wave_write method): Wave_write Objects.
                                                             (line   75)
* setconfig() (sqlite3.Connection method): Connection objects.
                                                             (line  660)
* setContentHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   25)
* setcontext() (in module decimal):      Context objects.    (line   18)
* setDaemon() (threading.Thread method): Thread objects.     (line  213)
* setdefault() (dict method):            Mapping Types — dict.
                                                             (line  225)
* setdefault() (http.cookies.Morsel method): Morsel Objects. (line  105)
* setdefaulttimeout() (in module socket): Other functions<2>.
                                                             (line  379)
* setdlopenflags() (in module sys):      sys — System-specific parameters and functions.
                                                             (line 1493)
* setDocumentLocator() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   10)
* setDTDHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   34)
* setegid() (in module os):              Process Parameters. (line  370)
* setEncoding() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   22)
* setEntityResolver() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   43)
* setErrorHandler() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   54)
* seteuid() (in module os):              Process Parameters. (line  376)
* setFeature() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   76)
* setfirstweekday() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line   53)
* setfirstweekday() (in module calendar): calendar — General calendar-related functions.
                                                             (line  348)
* setFormatter() (logging.Handler method): Handler Objects.  (line   48)
* setframerate() (wave.Wave_write method): Wave_write Objects.
                                                             (line   53)
* setgid() (in module os):               Process Parameters. (line  382)
* setgroups() (in module os):            Process Parameters. (line  388)
* seth() (in module turtle):             Turtle motion.      (line  166)
* setheading() (in module turtle):       Turtle motion.      (line  166)
* sethostname() (in module socket):      Other functions<2>. (line  386)
* setinputsizes() (sqlite3.Cursor method): Cursor objects.   (line  164)
* setitem() (in module operator):        operator — Standard operators as functions.
                                                             (line  205)
* setitimer() (in module signal):        Module contents<3>. (line  444)
* setLevel() (logging.Handler method):   Handler Objects.    (line   35)
* setLevel() (logging.Logger method):    Logger Objects.     (line  105)
* setlimit() (sqlite3.Connection method): Connection objects.
                                                             (line  614)
* setlocale() (in module locale):        locale — Internationalization services.
                                                             (line   26)
* setLocale() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   60)
* setLoggerClass() (in module logging):  Module-Level Functions.
                                                             (line  323)
* setlogmask() (in module syslog):       syslog — Unix syslog library routines.
                                                             (line   96)
* setLogRecordFactory() (in module logging): Module-Level Functions.
                                                             (line  334)
* setMaxConns() (urllib.request.CacheFTPHandler method): CacheFTPHandler Objects.
                                                             (line   13)
* setmode() (in module msvcrt):          File Operations.    (line   38)
* setName() (threading.Thread method):   Thread objects.     (line  157)
* setnchannels() (wave.Wave_write method): Wave_write Objects.
                                                             (line   37)
* setnframes() (wave.Wave_write method): Wave_write Objects. (line   64)
* setns() (in module os):                Process Parameters. (line  403)
* setoutputsize() (sqlite3.Cursor method): Cursor objects.   (line  168)
* SetParamEntityParsing() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   53)
* setparams() (wave.Wave_write method):  Wave_write Objects. (line   88)
* setpassword() (zipfile.ZipFile method): ZipFile objects.   (line  239)
* setpgid() (in module os):              Process Parameters. (line  450)
* setpgrp() (in module os):              Process Parameters. (line  442)
* setpos() (in module turtle):           Turtle motion.      (line   74)
* setpos() (wave.Wave_read method):      Wave_read Objects.  (line   83)
* setposition() (in module turtle):      Turtle motion.      (line   74)
* setpriority() (in module os):          Process Parameters. (line  458)
* setprofile_all_threads() (in module threading): Reference<2>.
                                                             (line  142)
* setprofile() (in module sys):          sys — System-specific parameters and functions.
                                                             (line 1514)
* setprofile() (in module threading):    Reference<2>.       (line  136)
* setProperty() (xml.sax.xmlreader.XMLReader method): XMLReader Objects.
                                                             (line   90)
* setPublicId() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line    6)
* setquota() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  267)
* setraw() (in module tty):              tty — Terminal control functions.
                                                             (line   43)
* setrecursionlimit() (in module sys):   sys — System-specific parameters and functions.
                                                             (line 1571)
* setregid() (in module os):             Process Parameters. (line  474)
* SetReparseDeferralEnabled() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   81)
* setresgid() (in module os):            Process Parameters. (line  480)
* setresuid() (in module os):            Process Parameters. (line  488)
* setreuid() (in module os):             Process Parameters. (line  496)
* setrlimit() (in module resource):      Resource Limits.    (line   31)
* setsampwidth() (wave.Wave_write method): Wave_write Objects.
                                                             (line   45)
* setscrreg() (curses.window method):    Window Objects.     (line  515)
* setsid() (in module os):               Process Parameters. (line  509)
* setsockopt() (socket.socket method):   Socket Objects.     (line  559)
* setstate() (codecs.IncrementalDecoder method): IncrementalDecoder Objects.
                                                             (line   59)
* setstate() (codecs.IncrementalEncoder method): IncrementalEncoder Objects.
                                                             (line   51)
* setstate() (in module random):         Bookkeeping functions.
                                                             (line   38)
* setstate() (random.Random method):     Alternative Generator.
                                                             (line   28)
* setStream() (logging.StreamHandler method): StreamHandler. (line   32)
* setswitchinterval (in module sys):     Thread State and the Global Interpreter Lock.
                                                             (line   15)
* setswitchinterval() (in module sys):   sys — System-specific parameters and functions.
                                                             (line 1589)
* setswitchinterval() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  290)
* setSystemId() (xml.sax.xmlreader.InputSource method): InputSource Objects.
                                                             (line   14)
* setsyx() (in module curses):           Functions<6>.       (line  476)
* setTarget() (logging.handlers.MemoryHandler method): MemoryHandler.
                                                             (line   68)
* setter (C type):                       Defining Getters and Setters.
                                                             (line   42)
* settimeout() (socket.socket method):   Socket Objects.     (line  543)
* setTimeout() (urllib.request.CacheFTPHandler method): CacheFTPHandler Objects.
                                                             (line    9)
* settrace_all_threads() (in module threading): Reference<2>.
                                                             (line  120)
* settrace() (in module sys):            sys — System-specific parameters and functions.
                                                             (line 1602)
* settrace() (in module threading):      Reference<2>.       (line  114)
* setuid() (in module os):               Process Parameters. (line  516)
* setundobuffer() (in module turtle):    Special Turtle methods.
                                                             (line   61)
* SETUP_ANNOTATIONS (opcode):            Python Bytecode Instructions.
                                                             (line  432)
* SETUP_CLEANUP (opcode):                Python Bytecode Instructions.
                                                             (line 1404)
* setup_environ() (wsgiref.handlers.BaseHandler method): wsgiref handlers – server/gateway base classes.
                                                             (line  197)
* SETUP_FINALLY (opcode):                Python Bytecode Instructions.
                                                             (line 1397)
* setup_python() (venv.EnvBuilder method): API<2>.           (line  153)
* setup_scripts() (venv.EnvBuilder method): API<2>.          (line  161)
* setup_testing_defaults() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line   70)
* SETUP_WITH (opcode):                   Python Bytecode Instructions.
                                                             (line 1412)
* setup() (in module turtle):            Methods specific to Screen not inherited from TurtleScreen.
                                                             (line   20)
* setup() (socketserver.BaseRequestHandler method): Request Handler Objects.
                                                             (line   14)
* setUp() (unittest.TestCase method):    Test cases.         (line   31)
* setUpClass() (unittest.TestCase method): Test cases.       (line   53)
* setUpModule() (in module unittest):    setUpModule and tearDownModule.
                                                             (line    6)
* setupterm() (in module curses):        Functions<6>.       (line  481)
* SetValue() (in module winreg):         Functions<13>.      (line  418)
* SetValueEx() (in module winreg):       Functions<13>.      (line  449)
* setworldcoordinates() (in module turtle): Window control.  (line  117)
* setx() (in module turtle):             Turtle motion.      (line  138)
* setxattr() (in module os):             Linux extended attributes.
                                                             (line   57)
* sety() (in module turtle):             Turtle motion.      (line  152)
* SF_APPEND (in module stat):            stat — Interpreting stat results.
                                                             (line  414)
* SF_ARCHIVED (in module stat):          stat — Interpreting stat results.
                                                             (line  406)
* SF_DATALESS (in module stat):          stat — Interpreting stat results.
                                                             (line  438)
* SF_FIRMLINK (in module stat):          stat — Interpreting stat results.
                                                             (line  432)
* SF_IMMUTABLE (in module stat):         stat — Interpreting stat results.
                                                             (line  410)
* SF_MNOWAIT (in module os):             File Descriptor Operations.
                                                             (line  792)
* SF_NOCACHE (in module os):             File Descriptor Operations.
                                                             (line  803)
* SF_NODISKIO (in module os):            File Descriptor Operations.
                                                             (line  792)
* SF_NOUNLINK (in module stat):          stat — Interpreting stat results.
                                                             (line  424)
* SF_RESTRICTED (in module stat):        stat — Interpreting stat results.
                                                             (line  418)
* SF_SETTABLE (in module stat):          stat — Interpreting stat results.
                                                             (line  384)
* SF_SNAPSHOT (in module stat):          stat — Interpreting stat results.
                                                             (line  428)
* SF_SUPPORTED (in module stat):         stat — Interpreting stat results.
                                                             (line  390)
* SF_SYNC (in module os):                File Descriptor Operations.
                                                             (line  792)
* SF_SYNTHETIC (in module stat):         stat — Interpreting stat results.
                                                             (line  398)
* sha1() (in module hashlib):            Constructors.       (line   22)
* sha224() (in module hashlib):          Constructors.       (line   24)
* sha256() (in module hashlib):          Constructors.       (line   26)
* sha3_224() (in module hashlib):        Constructors.       (line   32)
* sha3_256() (in module hashlib):        Constructors.       (line   34)
* sha3_384() (in module hashlib):        Constructors.       (line   36)
* sha3_512() (in module hashlib):        Constructors.       (line   38)
* sha384() (in module hashlib):          Constructors.       (line   28)
* sha512() (in module hashlib):          Constructors.       (line   30)
* shake_128() (in module hashlib):       SHAKE variable length digests.
                                                             (line    6)
* shake_256() (in module hashlib):       SHAKE variable length digests.
                                                             (line    8)
* Shape (class in turtle):               Public classes.     (line   43)
* shape (memoryview attribute):          Memory Views.       (line  454)
* shape() (in module turtle):            Appearance.         (line    6)
* shapesize() (in module turtle):        Appearance.         (line   52)
* shapetransform() (in module turtle):   Appearance.         (line  137)
* share() (socket.socket method):        Socket Objects.     (line  591)
* ShareableList (class in multiprocessing.shared_memory): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  272)
* ShareableList() (multiprocessing.managers.SharedMemoryManager method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  232)
* Shared Memory:                         multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line   10)
* shared_ciphers() (ssl.SSLSocket method): SSL sockets.      (line  238)
* shared_memory (sys._emscripten_info attribute): sys — System-specific parameters and functions.
                                                             (line  363)
* SharedMemory (class in multiprocessing.shared_memory): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line   33)
* SharedMemory() (multiprocessing.managers.SharedMemoryManager method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  227)
* SharedMemoryManager (class in multiprocessing.managers): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  200)
* shearfactor() (in module turtle):      Appearance.         (line   83)
* Shelf (class in shelve):               Restrictions.       (line   27)
* shield() (in module asyncio):          Shielding from cancellation.
                                                             (line    6)
* shift_path_info() (in module wsgiref.util): wsgiref util – WSGI environment utilities.
                                                             (line   40)
* shift() (decimal.Context method):      Context objects.    (line  525)
* shift() (decimal.Decimal method):      Decimal objects.    (line  555)
* shifting; operation:                   Shifting operations.
                                                             (line    6)
* shifting; operations:                  Bitwise Operations on Integer Types.
                                                             (line    6)
* shlex (class in shlex):                shlex — Simple lexical analysis.
                                                             (line   92)
* shm (multiprocessing.shared_memory.ShareableList attribute): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  346)
* SHORT_TIMEOUT (in module test.support): test support — Utilities for the Python test suite.
                                                             (line   80)
* shortDescription() (unittest.TestCase method): Test cases. (line  753)
* shorten() (in module textwrap):        textwrap — Text wrapping and filling.
                                                             (line   48)
* shouldFlush() (logging.handlers.BufferingHandler method): MemoryHandler.
                                                             (line   36)
* shouldFlush() (logging.handlers.MemoryHandler method): MemoryHandler.
                                                             (line   72)
* shouldRollover() (logging.handlers.RotatingFileHandler method): RotatingFileHandler.
                                                             (line   52)
* shouldRollover() (logging.handlers.TimedRotatingFileHandler method): TimedRotatingFileHandler.
                                                             (line  121)
* shouldStop (unittest.TestResult attribute): Loading and running tests.
                                                             (line  281)
* show_code() (in module dis):           Analysis functions. (line   26)
* show_flag_values() (in module enum):   Utilities and decorators.
                                                             (line  102)
* show() (curses.panel.Panel method):    Panel Objects.      (line   49)
* show() (tkinter.commondialog.Dialog method): tkinter commondialog — Dialog window templates.
                                                             (line   15)
* show() (tkinter.messagebox.Message method): tkinter messagebox — Tkinter message prompts.
                                                             (line   82)
* showerror() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  105)
* showinfo() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line   91)
* showsyntaxerror() (code.InteractiveInterpreter method): Interactive Interpreter Objects.
                                                             (line   44)
* showtraceback() (code.InteractiveInterpreter method): Interactive Interpreter Objects.
                                                             (line   53)
* showturtle() (in module turtle):       Visibility.         (line   15)
* showwarning() (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line   99)
* showwarning() (in module warnings):    Available Functions.
                                                             (line   91)
* shuffle() (in module random):          Functions for sequences.
                                                             (line   53)
* SHUT_RD (in module socket):            Constants<8>.       (line  375)
* SHUT_RDWR (in module socket):          Constants<8>.       (line  375)
* SHUT_WR (in module socket):            Constants<8>.       (line  375)
* ShutDown:                              queue — A synchronized queue class.
                                                             (line   92)
* shutdown_asyncgens() (asyncio.loop method): Running and stopping the loop.
                                                             (line   56)
* shutdown_default_executor() (asyncio.loop method): Running and stopping the loop.
                                                             (line   77)
* shutdown() (asyncio.Queue method):     Queue.              (line   83)
* shutdown() (concurrent.futures.Executor method): Executor Objects.
                                                             (line   53)
* shutdown() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  272)
* shutdown() (in module logging):        Module-Level Functions.
                                                             (line  312)
* shutdown() (multiprocessing.managers.BaseManager method): Managers.
                                                             (line   85)
* shutdown() (queue.Queue method):       Terminating queues. (line    9)
* shutdown() (socket.socket method):     Socket Objects.     (line  582)
* shutdown() (socketserver.BaseServer method): Server Objects.
                                                             (line   54)
* SI (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   69)
* side_effect (unittest.mock.Mock attribute): The Mock Class.
                                                             (line  368)
* SIG_BLOCK (in module signal):          Module contents<3>. (line  262)
* SIG_DFL (in module signal):            Module contents<3>. (line   46)
* SIG_IGN (in module signal):            Module contents<3>. (line   54)
* SIG_SETMASK (in module signal):        Module contents<3>. (line  277)
* SIG_UNBLOCK (in module signal):        Module contents<3>. (line  269)
* SIGABRT (in module signal):            Module contents<3>. (line   59)
* SIGALRM (in module signal):            Module contents<3>. (line   63)
* SIGBREAK (in module signal):           Module contents<3>. (line   69)
* SIGBUS (in module signal):             Module contents<3>. (line   75)
* SIGCHLD (in module signal):            Module contents<3>. (line   81)
* SIGCLD (in module signal):             Module contents<3>. (line   87)
* SIGCONT (in module signal):            Module contents<3>. (line   93)
* SIGFPE (in module signal):             Module contents<3>. (line   99)
* SIGHUP (in module signal):             Module contents<3>. (line  109)
* SIGILL (in module signal):             Module contents<3>. (line  116)
* SIGINT (C macro):                      Signal Handling<2>. (line    7)
* SIGINT (C macro) <1>:                  Signal Handling<2>. (line   46)
* SIGINT (in module signal):             Module contents<3>. (line  120)
* siginterrupt() (in module signal):     Module contents<3>. (line  519)
* SIGKILL (in module signal):            Module contents<3>. (line  126)
* Sigmasks (class in signal):            Module contents<3>. (line   31)
* signal() (in module signal):           Module contents<3>. (line  534)
* Signals (class in signal):             Module contents<3>. (line   17)
* Signature (class in inspect):          Introspecting callables with the Signature object.
                                                             (line   73)
* signature (inspect.BoundArguments attribute): Introspecting callables with the Signature object.
                                                             (line  362)
* signature() (in module inspect):       Introspecting callables with the Signature object.
                                                             (line   12)
* sigpending() (in module signal):       Module contents<3>. (line  562)
* SIGPIPE (in module signal):            Module contents<3>. (line  134)
* SIGPROF (in module signal):            Module contents<3>. (line  142)
* SIGQUIT (in module signal):            Module contents<3>. (line  148)
* SIGSEGV (in module signal):            Module contents<3>. (line  154)
* SIGSTKFLT (in module signal):          Module contents<3>. (line  164)
* SIGSTOP (in module signal):            Module contents<3>. (line  158)
* SIGTERM (in module signal):            Module contents<3>. (line  176)
* sigtimedwait() (in module signal):     Module contents<3>. (line  623)
* SIGUSR1 (in module signal):            Module contents<3>. (line  180)
* SIGUSR2 (in module signal):            Module contents<3>. (line  186)
* SIGVTALRM (in module signal):          Module contents<3>. (line  192)
* sigwait() (in module signal):          Module contents<3>. (line  577)
* sigwaitinfo() (in module signal):      Module contents<3>. (line  594)
* SIGWINCH (in module signal):           Module contents<3>. (line  198)
* SIGXCPU (in module signal):            Module contents<3>. (line  204)
* SIMPLE (inspect.BufferFlags attribute): Buffer flags.      (line   15)
* Simple Mail Transfer Protocol:         smtplib — SMTP protocol client.
                                                             (line    8)
* simple; statement:                     Simple statements.  (line    6)
* SimpleCookie (class in http.cookies):  http cookies — HTTP state management.
                                                             (line   48)
* simplefilter() (in module warnings):   Available Functions.
                                                             (line  125)
* SimpleHandler (class in wsgiref.handlers): wsgiref handlers – server/gateway base classes.
                                                             (line   69)
* SimpleHTTPRequestHandler (class in http.server): http server — HTTP servers.
                                                             (line  343)
* SimpleNamespace (class in types):      Additional Utility Classes and Functions.
                                                             (line    6)
* SimpleQueue (class in multiprocessing): Pipes and Queues.  (line  222)
* SimpleQueue (class in queue):          queue — A synchronized queue class.
                                                             (line   73)
* SimpleXMLRPCRequestHandler (class in xmlrpc.server): xmlrpc server — Basic XML-RPC servers.
                                                             (line   63)
* SimpleXMLRPCServer (class in xmlrpc.server): xmlrpc server — Basic XML-RPC servers.
                                                             (line   24)
* sin() (in module cmath):               Trigonometric functions<2>.
                                                             (line   27)
* sin() (in module math):                Trigonometric functions.
                                                             (line   34)
* single dispatch:                       Glossary.           (line 1544)
* SingleAddressHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  216)
* singledispatch() (in module functools): functools — Higher-order functions and operations on callable objects.
                                                             (line  423)
* singledispatchmethod (class in functools): functools — Higher-order functions and operations on callable objects.
                                                             (line  597)
* singleton; tuple:                      Immutable sequences.
                                                             (line   29)
* sinh() (in module cmath):              Hyperbolic functions<2>.
                                                             (line   27)
* sinh() (in module math):               Hyperbolic functions.
                                                             (line   25)
* SIO_KEEPALIVE_VALS (in module socket): Constants<8>.       (line  247)
* SIO_LOOPBACK_FAST_PATH (in module socket): Constants<8>.   (line  247)
* SIO_RCVALL (in module socket):         Constants<8>.       (line  247)
* site command line option; -user-base:  Command-line interface<9>.
                                                             (line   18)
* site command line option; -user-site:  Command-line interface<9>.
                                                             (line   22)
* site_maps() (urllib.robotparser.RobotFileParser method): urllib robotparser — Parser for robots txt.
                                                             (line   71)
* site-packages; directory:              site — Site-specific configuration hook.
                                                             (line   25)
* sitecustomize:                         The Customization Modules.
                                                             (line    6)
* sitecustomize <1>:                     The Customization Modules.
                                                             (line   19)
* sixtofour (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  313)
* size (multiprocessing.shared_memory.SharedMemory attribute): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  125)
* size (struct.Struct attribute):        Classes<3>.         (line   61)
* size (tarfile.TarInfo attribute):      TarInfo Objects.    (line   65)
* size (tracemalloc.Statistic attribute): Statistic.         (line   19)
* size (tracemalloc.StatisticDiff attribute): StatisticDiff. (line   26)
* size (tracemalloc.Trace attribute):    Trace.              (line   23)
* size_diff (tracemalloc.StatisticDiff attribute): StatisticDiff.
                                                             (line   32)
* SIZE_MAX (C macro):                    Integer Objects.    (line  273)
* size() (ftplib.FTP method):            FTP objects.        (line  351)
* size() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  312)
* Sized (class in collections.abc):      Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line   15)
* Sized (class in typing):               Aliases to other ABCs in collections abc.
                                                             (line   68)
* sizeof_digit (sys.int_info attribute): sys — System-specific parameters and functions.
                                                             (line 1152)
* sizeof() (in module ctypes):           Utility functions.  (line  223)
* SKIP (in module doctest):              Option Flags.       (line   90)
* skip_if_broken_multiprocessing_synchronize() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  726)
* skip_unless_bind_unix_socket() (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   59)
* skip_unless_symlink() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  125)
* skip_unless_xattr() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  130)
* skip() (in module unittest):           Skipping tests and expected failures.
                                                             (line   85)
* skipIf() (in module unittest):         Skipping tests and expected failures.
                                                             (line   90)
* skipinitialspace (csv.Dialect attribute): Dialects and Formatting Parameters.
                                                             (line   81)
* skipped (doctest.TestResults attribute): TestResults objects.
                                                             (line   16)
* skipped (unittest.TestResult attribute): Loading and running tests.
                                                             (line  256)
* skippedEntity() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  173)
* skips (doctest.DocTestRunner attribute): DocTestRunner objects.
                                                             (line  142)
* SkipTest:                              Skipping tests and expected failures.
                                                             (line  105)
* skipTest() (unittest.TestCase method): Test cases.         (line   95)
* skipUnless() (in module unittest):     Skipping tests and expected failures.
                                                             (line   94)
* SLASH (in module token):               token — Constants used with Python parse trees.
                                                             (line  206)
* SLASHEQUAL (in module token):          token — Constants used with Python parse trees.
                                                             (line  272)
* sleep() (in module asyncio):           Sleeping.           (line    6)
* sleep() (in module time):              Functions<5>.       (line  265)
* sleeping_retry() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  218)
* slice:                                 Slicings.           (line    6)
* slice <1>:                             Glossary.           (line 1549)
* slice (built-in class):                Built-in Functions. (line 1773)
* Slice (class in ast):                  Subscripting.       (line   27)
* slice; assignment:                     Mutable Sequence Types.
                                                             (line   16)
* slice; operation:                      Common Sequence Operations.
                                                             (line   21)
* slicing:                               Sequences.          (line   14)
* slicing <1>:                           Mutable sequences.  (line    6)
* slicing <2>:                           Slicings.           (line    6)
* slicing; assignment:                   Assignment statements.
                                                             (line  125)
* slow_callback_duration (asyncio.loop attribute): Enabling debug mode.
                                                             (line   21)
* SMALLEST (in module test.support):     test support — Utilities for the Python test suite.
                                                             (line  189)
* SMTP (class in smtplib):               smtplib — SMTP protocol client.
                                                             (line   21)
* SMTP (in module email.policy):         email policy Policy Objects.
                                                             (line  509)
* smtp_code (smtplib.SMTPResponseException attribute): smtplib — SMTP protocol client.
                                                             (line  144)
* smtp_error (smtplib.SMTPResponseException attribute): smtplib — SMTP protocol client.
                                                             (line  148)
* SMTP_SSL (class in smtplib):           smtplib — SMTP protocol client.
                                                             (line   75)
* SMTP; protocol:                        smtplib — SMTP protocol client.
                                                             (line    8)
* SMTPAuthenticationError:               smtplib — SMTP protocol client.
                                                             (line  187)
* SMTPConnectError:                      smtplib — SMTP protocol client.
                                                             (line  172)
* SMTPDataError:                         smtplib — SMTP protocol client.
                                                             (line  168)
* SMTPException:                         smtplib — SMTP protocol client.
                                                             (line  124)
* SMTPHandler (class in logging.handlers): SMTPHandler.      (line    9)
* SMTPHeloError:                         smtplib — SMTP protocol client.
                                                             (line  177)
* SMTPNotSupportedError:                 smtplib — SMTP protocol client.
                                                             (line  181)
* SMTPRecipientsRefused:                 smtplib — SMTP protocol client.
                                                             (line  158)
* SMTPResponseException:                 smtplib — SMTP protocol client.
                                                             (line  138)
* SMTPSenderRefused:                     smtplib — SMTP protocol client.
                                                             (line  152)
* SMTPServerDisconnected:                smtplib — SMTP protocol client.
                                                             (line  132)
* SMTPUTF8 (in module email.policy):     email policy Policy Objects.
                                                             (line  515)
* Snapshot (class in tracemalloc):       Snapshot.           (line    6)
* SND_ALIAS (in module winsound):        winsound — Sound-playing interface for Windows.
                                                             (line   49)
* SND_APPLICATION (in module winsound):  winsound — Sound-playing interface for Windows.
                                                             (line  130)
* SND_ASYNC (in module winsound):        winsound — Sound-playing interface for Windows.
                                                             (line  111)
* SND_FILENAME (in module winsound):     winsound — Sound-playing interface for Windows.
                                                             (line   44)
* SND_LOOP (in module winsound):         winsound — Sound-playing interface for Windows.
                                                             (line   90)
* SND_MEMORY (in module winsound):       winsound — Sound-playing interface for Windows.
                                                             (line   96)
* SND_NODEFAULT (in module winsound):    winsound — Sound-playing interface for Windows.
                                                             (line  115)
* SND_NOSTOP (in module winsound):       winsound — Sound-playing interface for Windows.
                                                             (line  120)
* SND_NOWAIT (in module winsound):       winsound — Sound-playing interface for Windows.
                                                             (line  124)
* SND_PURGE (in module winsound):        winsound — Sound-playing interface for Windows.
                                                             (line  105)
* sni_callback (ssl.SSLContext attribute): SSL contexts.     (line  284)
* sniff() (csv.Sniffer method):          Module Contents<2>. (line  234)
* Sniffer (class in csv):                Module Contents<2>. (line  228)
* SO (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   66)
* SO_INCOMING_CPU (in module socket):    Constants<8>.       (line  335)
* sock_accept() (asyncio.loop method):   Working with socket objects directly.
                                                             (line  107)
* SOCK_CLOEXEC (in module socket):       Constants<8>.       (line   38)
* sock_connect() (asyncio.loop method):  Working with socket objects directly.
                                                             (line   88)
* SOCK_DGRAM (in module socket):         Constants<8>.       (line   27)
* SOCK_MAX_SIZE (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  123)
* SOCK_NONBLOCK (in module socket):      Constants<8>.       (line   38)
* SOCK_RAW (in module socket):           Constants<8>.       (line   27)
* SOCK_RDM (in module socket):           Constants<8>.       (line   27)
* sock_recv_into() (asyncio.loop method): Working with socket objects directly.
                                                             (line   26)
* sock_recv() (asyncio.loop method):     Working with socket objects directly.
                                                             (line   12)
* sock_recvfrom_into() (asyncio.loop method): Working with socket objects directly.
                                                             (line   48)
* sock_recvfrom() (asyncio.loop method): Working with socket objects directly.
                                                             (line   37)
* sock_sendall() (asyncio.loop method):  Working with socket objects directly.
                                                             (line   59)
* sock_sendfile() (asyncio.loop method): Working with socket objects directly.
                                                             (line  130)
* sock_sendto() (asyncio.loop method):   Working with socket objects directly.
                                                             (line   77)
* SOCK_SEQPACKET (in module socket):     Constants<8>.       (line   27)
* SOCK_STREAM (in module socket):        Constants<8>.       (line   27)
* socket (class in socket):              Creating sockets.   (line    8)
* socket (socketserver.BaseServer attribute): Server Objects.
                                                             (line   88)
* socket_type (socketserver.BaseServer attribute): Server Objects.
                                                             (line  111)
* socket() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  277)
* socket() (in module socket):           select — Waiting for I/O completion.
                                                             (line  143)
* SocketHandler (class in logging.handlers): SocketHandler.  (line   10)
* socketpair() (in module socket):       Creating sockets.   (line   64)
* sockets (asyncio.Server attribute):    Server objects.     (line  128)
* SocketType (in module socket):         Creating sockets.   (line  185)
* soft deprecated:                       Glossary.           (line 1557)
* soft keyword:                          Soft Keywords.      (line    6)
* SOFT_KEYWORD (in module token):        token — Constants used with Python parse trees.
                                                             (line  151)
* softkwlist (in module keyword):        keyword — Testing for Python keywords.
                                                             (line   30)
* SOH (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   21)
* SOL_ALG (in module socket):            Constants<8>.       (line  263)
* SOL_RDS (in module socket):            Constants<8>.       (line  234)
* SOMAXCONN (in module socket):          Constants<8>.       (line   54)
* sort_stats() (pstats.Stats method):    The Stats Class.    (line   67)
* sort() (imaplib.IMAP4 method):         IMAP4 Objects.      (line  281)
* sort() (list method):                  Lists<2>.           (line   39)
* sortdict() (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line  271)
* sortTestMethodsUsing (unittest.TestLoader attribute): Loading and running tests.
                                                             (line  194)
* source (doctest.Example attribute):    Example Objects.    (line   16)
* source (pdb command):                  Debugger commands.  (line  284)
* source (shlex.shlex attribute):        shlex Objects.      (line  151)
* source character set:                  Encoding declarations.
                                                             (line    6)
* SOURCE_DATE_EPOCH:                     py_compile<3>.      (line    7)
* SOURCE_DATE_EPOCH <1>:                 Library<138>.       (line  451)
* SOURCE_DATE_EPOCH <2>:                 Build<66>.          (line   15)
* SOURCE_DATE_EPOCH <3>:                 py_compile — Compile Python source files.
                                                             (line   66)
* SOURCE_DATE_EPOCH <4>:                 py_compile — Compile Python source files.
                                                             (line   82)
* SOURCE_DATE_EPOCH <5>:                 py_compile — Compile Python source files.
                                                             (line   86)
* SOURCE_DATE_EPOCH <6>:                 Command-line use.   (line   97)
* source_from_cache() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line   58)
* source_hash() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  160)
* SOURCE_SUFFIXES (in module importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   13)
* source_to_code() (importlib.abc.InspectLoader static method): importlib abc – Abstract base classes related to import.
                                                             (line  240)
* SourceFileLoader (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  204)
* sourcehook() (shlex.shlex method):     shlex Objects.      (line   26)
* SourcelessFileLoader (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line  244)
* SourceLoader (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  325)
* SP (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line  120)
* space:                                 Indentation.        (line    6)
* space; in printf-style formatting:     printf-style String Formatting.
                                                             (line   69)
* space; in printf-style formatting <1>: printf-style Bytes Formatting.
                                                             (line   63)
* space; in string formatting:           Format specification mini-language.
                                                             (line   74)
* span() (re.Match method):              Match Objects.      (line  171)
* sparse (tarfile.TarInfo attribute):    TarInfo Objects.    (line  157)
* spawn_python() (in module test.support.script_helper): test support script_helper — Utilities for the Python execution tests.
                                                             (line   69)
* spawn() (in module pty):               pty — Pseudo-terminal utilities.
                                                             (line   42)
* spawnl() (in module os):               Process Management. (line  588)
* spawnle() (in module os):              Process Management. (line  588)
* spawnlp() (in module os):              Process Management. (line  588)
* spawnlpe() (in module os):             Process Management. (line  588)
* spawnv() (in module os):               Process Management. (line  588)
* spawnve() (in module os):              Process Management. (line  588)
* spawnvp() (in module os):              Process Management. (line  588)
* spawnvpe() (in module os):             Process Management. (line  588)
* spec_from_file_location() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  148)
* spec_from_loader() (in module importlib.util): importlib util – Utility code for importers.
                                                             (line  137)
* special method:                        Glossary.           (line 1568)
* special; attribute:                    The standard type hierarchy.
                                                             (line   13)
* special; method:                       Glossary.           (line 1572)
* SpecialFileError:                      Directory and files operations.
                                                             (line   52)
* SpecialFileError <1>:                  tarfile — Read and write tar archive files.
                                                             (line  247)
* specified_attributes (xml.parsers.expat.xmlparser attribute): XMLParser Objects<2>.
                                                             (line  204)
* speed() (in module turtle):            Turtle motion.      (line  336)
* Spinbox (class in tkinter.ttk):        ttk Spinbox.        (line    6)
* SPLICE_F_MORE (in module os):          File Descriptor Operations.
                                                             (line  861)
* SPLICE_F_MOVE (in module os):          File Descriptor Operations.
                                                             (line  861)
* SPLICE_F_NONBLOCK (in module os):      File Descriptor Operations.
                                                             (line  861)
* splice() (in module os):               File Descriptor Operations.
                                                             (line  833)
* split() (BaseExceptionGroup method):   Exception groups.   (line   73)
* split() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  396)
* split() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  396)
* split() (in module os.path):           os path — Common pathname manipulations.
                                                             (line  481)
* split() (in module re):                Functions<2>.       (line   80)
* split() (in module shlex):             shlex — Simple lexical analysis.
                                                             (line   17)
* split() (re.Pattern method):           Regular Expression Objects.
                                                             (line   80)
* split() (str method):                  String Methods<2>.  (line  701)
* splitdrive() (in module os.path):      os path — Common pathname manipulations.
                                                             (line  496)
* splitext() (in module os.path):        os path — Common pathname manipulations.
                                                             (line  551)
* splitlines() (bytearray method):       Bytes and Bytearray Operations.
                                                             (line  638)
* splitlines() (bytes method):           Bytes and Bytearray Operations.
                                                             (line  638)
* splitlines() (str method):             String Methods<2>.  (line  757)
* SplitResult (class in urllib.parse):   Structured Parse Results.
                                                             (line   55)
* SplitResultBytes (class in urllib.parse): Structured Parse Results.
                                                             (line   82)
* splitroot() (in module os.path):       os path — Common pathname manipulations.
                                                             (line  520)
* SpooledTemporaryFile (class in tempfile): tempfile — Generate temporary files and directories.
                                                             (line  152)
* sprintf-style formatting:              printf-style String Formatting.
                                                             (line    6)
* sprintf-style formatting <1>:          printf-style Bytes Formatting.
                                                             (line    6)
* SQLITE_DBCONFIG_DEFENSIVE (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_DQS_DDL (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_DQS_DML (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_FKEY (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_QPSG (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_TRIGGER (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_ENABLE_VIEW (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_LEGACY_ALTER_TABLE (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_LEGACY_FILE_FORMAT (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_RESET_DATABASE (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_TRIGGER_EQP (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_TRUSTED_SCHEMA (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DBCONFIG_WRITABLE_SCHEMA (in module sqlite3): Module constants.
                                                             (line  147)
* SQLITE_DENY (in module sqlite3):       Module constants.   (line   49)
* sqlite_errorcode (sqlite3.Error attribute): Exceptions<7>. (line   24)
* sqlite_errorname (sqlite3.Error attribute): Exceptions<7>. (line   30)
* SQLITE_IGNORE (in module sqlite3):     Module constants.   (line   49)
* SQLITE_OK (in module sqlite3):         Module constants.   (line   49)
* sqlite_version (in module sqlite3):    Module constants.   (line   78)
* sqlite_version_info (in module sqlite3): Module constants. (line   83)
* sqrt() (decimal.Context method):       Context objects.    (line  529)
* sqrt() (decimal.Decimal method):       Decimal objects.    (line  566)
* sqrt() (in module cmath):              Power and logarithmic functions.
                                                             (line   22)
* sqrt() (in module math):               Power exponential and logarithmic functions.
                                                             (line   89)
* ssizeargfunc (C type):                 Slot Type typedefs. (line  126)
* ssizeobjargproc (C type):              Slot Type typedefs. (line  130)
* SSL:                                   ssl — TLS/SSL wrapper for socket objects.
                                                             (line    8)
* ssl_version (ftplib.FTP_TLS attribute): FTP_TLS objects.   (line   83)
* SSLCertVerificationError:              Exceptions<16>.     (line   79)
* SSLContext (class in ssl):             SSL contexts.       (line   14)
* SSLEOFError:                           Exceptions<16>.     (line   71)
* SSLError:                              Exceptions<16>.     (line    6)
* SSLErrorNumber (class in ssl):         Constants<9>.       (line  549)
* SSLKEYLOGFILE:                         Context creation.   (line   34)
* SSLKEYLOGFILE <1>:                     Context creation.   (line   83)
* SSLObject (class in ssl):              Memory BIO support. (line   30)
* sslobject_class (ssl.SSLContext attribute): SSL contexts.  (line  471)
* SSLSession (class in ssl):             SSL session.        (line    8)
* SSLSocket (class in ssl):              SSL sockets.        (line    6)
* sslsocket_class (ssl.SSLContext attribute): SSL contexts.  (line  445)
* SSLSyscallError:                       Exceptions<16>.     (line   62)
* SSLv3 (ssl.TLSVersion attribute):      Constants<9>.       (line  571)
* SSLWantReadError:                      Exceptions<16>.     (line   44)
* SSLWantWriteError:                     Exceptions<16>.     (line   53)
* SSLZeroReturnError:                    Exceptions<16>.     (line   35)
* ST_ATIME (in module stat):             stat — Interpreting stat results.
                                                             (line  163)
* st_atime (os.stat_result attribute):   Files and Directories.
                                                             (line 1183)
* st_atime_ns (os.stat_result attribute): Files and Directories.
                                                             (line 1200)
* st_birthtime (os.stat_result attribute): Files and Directories.
                                                             (line 1226)
* st_birthtime_ns (os.stat_result attribute): Files and Directories.
                                                             (line 1234)
* st_blksize (os.stat_result attribute): Files and Directories.
                                                             (line 1270)
* st_blocks (os.stat_result attribute):  Files and Directories.
                                                             (line 1265)
* st_creator (os.stat_result attribute): Files and Directories.
                                                             (line 1306)
* ST_CTIME (in module stat):             stat — Interpreting stat results.
                                                             (line  171)
* st_ctime (os.stat_result attribute):   Files and Directories.
                                                             (line 1191)
* st_ctime_ns (os.stat_result attribute): Files and Directories.
                                                             (line 1214)
* ST_DEV (in module stat):               stat — Interpreting stat results.
                                                             (line  142)
* st_dev (os.stat_result attribute):     Files and Directories.
                                                             (line 1159)
* st_file_attributes (os.stat_result attribute): Files and Directories.
                                                             (line 1316)
* st_flags (os.stat_result attribute):   Files and Directories.
                                                             (line 1280)
* st_fstype (os.stat_result attribute):  Files and Directories.
                                                             (line 1295)
* st_gen (os.stat_result attribute):     Files and Directories.
                                                             (line 1288)
* ST_GID (in module stat):               stat — Interpreting stat results.
                                                             (line  154)
* st_gid (os.stat_result attribute):     Files and Directories.
                                                             (line 1171)
* ST_INO (in module stat):               stat — Interpreting stat results.
                                                             (line  138)
* st_ino (os.stat_result attribute):     Files and Directories.
                                                             (line 1150)
* ST_MODE (in module stat):              stat — Interpreting stat results.
                                                             (line  134)
* st_mode (os.stat_result attribute):    Files and Directories.
                                                             (line 1146)
* ST_MTIME (in module stat):             stat — Interpreting stat results.
                                                             (line  167)
* st_mtime (os.stat_result attribute):   Files and Directories.
                                                             (line 1187)
* st_mtime_ns (os.stat_result attribute): Files and Directories.
                                                             (line 1207)
* ST_NLINK (in module stat):             stat — Interpreting stat results.
                                                             (line  146)
* st_nlink (os.stat_result attribute):   Files and Directories.
                                                             (line 1163)
* st_rdev (os.stat_result attribute):    Files and Directories.
                                                             (line 1276)
* st_reparse_tag (os.stat_result attribute): Files and Directories.
                                                             (line 1326)
* st_rsize (os.stat_result attribute):   Files and Directories.
                                                             (line 1302)
* ST_SIZE (in module stat):              stat — Interpreting stat results.
                                                             (line  158)
* st_size (os.stat_result attribute):    Files and Directories.
                                                             (line 1175)
* st_type (os.stat_result attribute):    Files and Directories.
                                                             (line 1310)
* ST_UID (in module stat):               stat — Interpreting stat results.
                                                             (line  150)
* st_uid (os.stat_result attribute):     Files and Directories.
                                                             (line 1167)
* st() (in module turtle):               Visibility.         (line   15)
* stack (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line   75)
* stack viewer:                          Debug menu Shell window only.
                                                             (line   15)
* stack_effect() (in module dis):        Analysis functions. (line  185)
* stack_size() (in module _thread):      _thread — Low-level threading API.
                                                             (line  111)
* stack_size() (in module threading):    Reference<2>.       (line  158)
* stack; trace:                          Traceback objects.  (line    6)
* stack() (in module inspect):           The interpreter stack.
                                                             (line  171)
* stackable; streams:                    codecs — Codec registry and base classes.
                                                             (line    8)
* StackSummary (class in traceback):     StackSummary Objects.
                                                             (line   10)
* stamp() (in module turtle):            Turtle motion.      (line  280)
* Standard C:                            String and Bytes literals.
                                                             (line   74)
* standard input:                        Complete Python programs.
                                                             (line   25)
* standard library:                      Glossary.           (line 1575)
* standard_b64decode() (in module base64): RFC 4648 Encodings.
                                                             (line   54)
* standard_b64encode() (in module base64): RFC 4648 Encodings.
                                                             (line   49)
* standard; output:                      Expression statements.
                                                             (line   17)
* standend() (curses.window method):     Window Objects.     (line  520)
* standout() (curses.window method):     Window Objects.     (line  525)
* STAR (in module token):                token — Constants used with Python parse trees.
                                                             (line  203)
* STAREQUAL (in module token):           token — Constants used with Python parse trees.
                                                             (line  269)
* starmap_async() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line  165)
* starmap() (in module itertools):       Itertool Functions. (line  551)
* starmap() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line  154)
* Starred (class in ast):                Variables.          (line   40)
* start (range attribute):               Ranges.             (line   61)
* start (slice attribute):               Built-in Functions. (line 1786)
* start (slice object attribute):        Slice objects.      (line   10)
* start (slice object attribute) <1>:    Slicings.           (line   26)
* start (UnicodeError attribute):        Concrete exceptions.
                                                             (line  455)
* start_color() (in module curses):      Functions<6>.       (line  489)
* start_new_thread() (in module _thread): _thread — Low-level threading API.
                                                             (line   32)
* start_ns() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   76)
* start_server() (in module asyncio):    Streams.            (line   76)
* start_serving() (asyncio.Server method): Server objects.   (line   75)
* start_threads() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   22)
* start_tls() (asyncio.loop method):     TLS upgrade.        (line    6)
* start_tls() (asyncio.StreamWriter method): StreamWriter.   (line   84)
* start_unix_server() (in module asyncio): Streams.          (line  146)
* start() (in module tracemalloc):       Functions<11>.      (line   67)
* start() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   74)
* start() (multiprocessing.managers.BaseManager method): Managers.
                                                             (line   58)
* start() (multiprocessing.Process method): Process and exceptions.
                                                             (line   91)
* start() (re.Match method):             Match Objects.      (line  146)
* start() (threading.Thread method):     Thread objects.     (line   92)
* start() (tkinter.ttk.Progressbar method): ttk Progressbar. (line    8)
* start() (xml.etree.ElementTree.TreeBuilder method): TreeBuilder Objects.
                                                             (line   43)
* StartBoundaryNotFoundDefect:           email errors Exception and Defect classes.
                                                             (line   80)
* startCDATA() (xml.sax.handler.LexicalHandler method): LexicalHandler Objects.
                                                             (line   32)
* StartCdataSectionHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  390)
* StartDoctypeDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  273)
* startDocument() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   32)
* startDTD() (xml.sax.handler.LexicalHandler method): LexicalHandler Objects.
                                                             (line   23)
* startElement() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   81)
* StartElementHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  311)
* startElementNS() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line  100)
* STARTF_FORCEOFFFEEDBACK (in module subprocess): Windows Constants.
                                                             (line   47)
* STARTF_FORCEONFEEDBACK (in module subprocess): Windows Constants.
                                                             (line   38)
* STARTF_USESHOWWINDOW (in module subprocess): Windows Constants.
                                                             (line   33)
* STARTF_USESTDHANDLES (in module subprocess): Windows Constants.
                                                             (line   27)
* startfile() (in module os):            Process Management. (line  699)
* StartNamespaceDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  369)
* startPrefixMapping() (xml.sax.handler.ContentHandler method): ContentHandler Objects.
                                                             (line   49)
* StartResponse (class in wsgiref.types): wsgiref types – WSGI types for static type checking.
                                                             (line   11)
* startswith() (bytearray method):       Bytes and Bytearray Operations.
                                                             (line  253)
* startswith() (bytes method):           Bytes and Bytearray Operations.
                                                             (line  253)
* startswith() (str method):             String Methods<2>.  (line  830)
* startTest() (unittest.TestResult method): Loading and running tests.
                                                             (line  344)
* startTestRun() (unittest.TestResult method): Loading and running tests.
                                                             (line  353)
* starttls() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  299)
* starttls() (smtplib.SMTP method):      SMTP Objects.       (line  184)
* STARTUPINFO (class in subprocess):     Windows Popen Helpers.
                                                             (line    9)
* stat_result (class in os):             Files and Directories.
                                                             (line 1138)
* stat() (in module os):                 Files and Directories.
                                                             (line 1083)
* stat() (os.DirEntry method):           Files and Directories.
                                                             (line 1048)
* stat() (pathlib.Path method):          Querying file type and status.
                                                             (line   13)
* stat() (poplib.POP3 method):           POP3 Objects.       (line   52)
* state() (tkinter.ttk.Widget method):   ttk Widget.         (line   25)
* statement:                             Glossary.           (line 1587)
* statement grouping:                    Indentation.        (line    6)
* statement; assert:                     The assert statement.
                                                             (line    6)
* statement; assert <1>:                 Concrete exceptions.
                                                             (line   10)
* statement; assignment, annotated:      Annotated assignment statements.
                                                             (line    6)
* statement; assignment, augmented:      Augmented assignment statements.
                                                             (line    6)
* statement; async def:                  Coroutines<2>.      (line    8)
* statement; async for:                  Coroutine function definition.
                                                             (line   28)
* statement; async with:                 The async for statement.
                                                             (line   42)
* statement; break:                      The break statement.
                                                             (line    6)
* statement; break <1>:                  The while statement.
                                                             (line   17)
* statement; break <2>:                  The for statement.  (line   21)
* statement; break <3>:                  except* clause.     (line   66)
* statement; break <4>:                  finally clause.     (line   29)
* statement; class:                      Class definitions.  (line    6)
* statement; continue:                   The continue statement.
                                                             (line    6)
* statement; continue <1>:               The while statement.
                                                             (line   17)
* statement; continue <2>:               The for statement.  (line   21)
* statement; continue <3>:               except* clause.     (line   65)
* statement; continue <4>:               finally clause.     (line   29)
* statement; def:                        Function definitions.
                                                             (line    6)
* statement; del:                        Basic customization.
                                                             (line   54)
* statement; del <1>:                    The del statement<2>.
                                                             (line    6)
* statement; del <2>:                    Mutable Sequence Types.
                                                             (line   16)
* statement; del <3>:                    Mapping Types — dict.
                                                             (line    6)
* statement; except:                     Built-in Exceptions.
                                                             (line    6)
* statement; for:                        for Statements.     (line    6)
* statement; for <1>:                    The break statement.
                                                             (line    6)
* statement; for <2>:                    The continue statement.
                                                             (line    6)
* statement; for <3>:                    The for statement.  (line    6)
* statement; global:                     The del statement<2>.
                                                             (line   15)
* statement; global <1>:                 The global statement.
                                                             (line    6)
* statement; if:                         The if statement.   (line    6)
* statement; if <1>:                     Truth Value Testing.
                                                             (line    6)
* statement; import:                     Modules<3>.         (line    6)
* statement; import <1>:                 The import statement.
                                                             (line    6)
* statement; import <2>:                 Built-in Functions. (line 2173)
* statement; import <3>:                 site — Site-specific configuration hook.
                                                             (line   52)
* statement; match:                      The match statement.
                                                             (line    6)
* statement; nonlocal:                   The nonlocal statement.
                                                             (line    6)
* statement; pass:                       The pass statement. (line    6)
* statement; raise:                      The raise statement.
                                                             (line    6)
* statement; raise <1>:                  Built-in Exceptions.
                                                             (line   14)
* statement; return:                     The return statement.
                                                             (line    6)
* statement; return <1>:                 except* clause.     (line   66)
* statement; return <2>:                 finally clause.     (line   29)
* statement; try:                        Traceback objects.  (line   31)
* statement; try <1>:                    The try statement.  (line    6)
* statement; try <2>:                    Built-in Exceptions.
                                                             (line    6)
* statement; type:                       The type statement. (line    6)
* statement; while:                      The break statement.
                                                             (line    6)
* statement; while <1>:                  The continue statement.
                                                             (line    6)
* statement; while <2>:                  The while statement.
                                                             (line    6)
* statement; while <3>:                  Truth Value Testing.
                                                             (line    6)
* statement; with:                       With Statement Context Managers.
                                                             (line   14)
* statement; with <1>:                   The with statement. (line    6)
* statement; yield:                      The yield statement.
                                                             (line    6)
* static type checker:                   Glossary.           (line 1594)
* static_order() (graphlib.TopologicalSorter method): graphlib — Functionality to operate with graph-like structures.
                                                             (line  160)
* Statistic (class in tracemalloc):      Statistic.          (line    6)
* StatisticDiff (class in tracemalloc):  StatisticDiff.      (line    6)
* statistics() (tracemalloc.Snapshot method): Snapshot.      (line   56)
* StatisticsError:                       Exceptions<5>.      (line    8)
* Stats (class in pstats):               The Stats Class.    (line    9)
* status (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   61)
* status (urllib.response.addinfourl attribute): urllib response — Response classes used by urllib.
                                                             (line   24)
* status() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  312)
* statvfs() (in module os):              Files and Directories.
                                                             (line 1377)
* STD_ERROR_HANDLE (in module subprocess): Windows Constants.
                                                             (line   18)
* STD_INPUT_HANDLE (in module subprocess): Windows Constants.
                                                             (line    8)
* STD_OUTPUT_HANDLE (in module subprocess): Windows Constants.
                                                             (line   13)
* stderr (asyncio.subprocess.Process attribute): Interacting with Subprocesses.
                                                             (line  126)
* stderr (in module sys):                I/O objects also known as file objects.
                                                             (line    6)
* stderr (in module sys) <1>:            sys — System-specific parameters and functions.
                                                             (line 1807)
* stderr (in module sys) <2>:            Sub-interpreter support.
                                                             (line  112)
* stderr (in module sys) <3>:            Sub-interpreter support.
                                                             (line  197)
* stderr (subprocess.CalledProcessError attribute): Using the subprocess Module.
                                                             (line  229)
* stderr (subprocess.CompletedProcess attribute): Using the subprocess Module.
                                                             (line  128)
* stderr (subprocess.Popen attribute):   Popen Objects.      (line  134)
* stderr (subprocess.TimeoutExpired attribute): Using the subprocess Module.
                                                             (line  193)
* stdev (statistics.NormalDist attribute): NormalDist objects.
                                                             (line   35)
* stdev() (in module statistics):        Function details.   (line  435)
* stdin (asyncio.subprocess.Process attribute): Interacting with Subprocesses.
                                                             (line  116)
* stdin (in module sys):                 I/O objects also known as file objects.
                                                             (line    6)
* stdin (in module sys) <1>:             sys — System-specific parameters and functions.
                                                             (line 1807)
* stdin (in module sys) <2>:             Sub-interpreter support.
                                                             (line  112)
* stdin (in module sys) <3>:             Sub-interpreter support.
                                                             (line  197)
* stdin (subprocess.Popen attribute):    Popen Objects.      (line  115)
* stdio:                                 I/O objects also known as file objects.
                                                             (line    6)
* stdlib:                                Glossary.           (line 1600)
* stdlib_module_names (in module sys):   sys — System-specific parameters and functions.
                                                             (line 1897)
* stdout (asyncio.subprocess.Process attribute): Interacting with Subprocesses.
                                                             (line  121)
* STDOUT (in module subprocess):         Using the subprocess Module.
                                                             (line  156)
* stdout (in module sys):                I/O objects also known as file objects.
                                                             (line    6)
* stdout (in module sys) <1>:            sys — System-specific parameters and functions.
                                                             (line 1807)
* stdout (in module sys) <2>:            Sub-interpreter support.
                                                             (line  112)
* stdout (in module sys) <3>:            Sub-interpreter support.
                                                             (line  197)
* stdout (subprocess.CalledProcessError attribute): Using the subprocess Module.
                                                             (line  225)
* stdout (subprocess.CompletedProcess attribute): Using the subprocess Module.
                                                             (line  118)
* stdout (subprocess.Popen attribute):   Popen Objects.      (line  124)
* stdout (subprocess.TimeoutExpired attribute): Using the subprocess Module.
                                                             (line  189)
* stem (pathlib.PurePath attribute):     Methods and properties.
                                                             (line  161)
* step (pdb command):                    Debugger commands.  (line  196)
* step (range attribute):                Ranges.             (line   70)
* step (slice attribute):                Built-in Functions. (line 1790)
* step (slice object attribute):         Slice objects.      (line   10)
* step (slice object attribute) <1>:     Slicings.           (line   26)
* step() (tkinter.ttk.Progressbar method): ttk Progressbar.  (line   15)
* stls() (poplib.POP3 method):           POP3 Objects.       (line  114)
* stop (range attribute):                Ranges.             (line   66)
* stop (slice attribute):                Built-in Functions. (line 1788)
* stop (slice object attribute):         Slice objects.      (line   10)
* stop (slice object attribute) <1>:     Slicings.           (line   26)
* stop_here() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  243)
* STOP_ITERATION (monitoring event):     Events.             (line   81)
* stop() (asyncio.loop method):          Running and stopping the loop.
                                                             (line   31)
* stop() (in module tracemalloc):        Functions<11>.      (line   97)
* stop() (logging.handlers.QueueListener method): QueueListener.
                                                             (line   84)
* stop() (tkinter.ttk.Progressbar method): ttk Progressbar.  (line   21)
* stop() (unittest.TestResult method):   Loading and running tests.
                                                             (line  324)
* StopAsyncIteration:                    Concrete exceptions.
                                                             (line  297)
* StopIteration:                         Concrete exceptions.
                                                             (line  266)
* stopListening() (in module logging.config): Configuration functions.
                                                             (line  173)
* stopTest() (unittest.TestResult method): Loading and running tests.
                                                             (line  348)
* stopTestRun() (unittest.TestResult method): Loading and running tests.
                                                             (line  359)
* storbinary() (ftplib.FTP method):      FTP objects.        (line  217)
* Store (class in ast):                  Variables.          (line   11)
* STORE_ACTIONS (optparse.Option attribute): Adding new actions.
                                                             (line   34)
* STORE_ATTR (opcode):                   Python Bytecode Instructions.
                                                             (line  604)
* STORE_DEREF (opcode):                  Python Bytecode Instructions.
                                                             (line  997)
* STORE_FAST (opcode):                   Python Bytecode Instructions.
                                                             (line  947)
* STORE_FAST_LOAD_FAST (opcode):         Python Bytecode Instructions.
                                                             (line  958)
* STORE_FAST_STORE_FAST (opcode):        Python Bytecode Instructions.
                                                             (line  951)
* STORE_GLOBAL (opcode):                 Python Bytecode Instructions.
                                                             (line  625)
* STORE_NAME (opcode):                   Python Bytecode Instructions.
                                                             (line  562)
* STORE_SLICE (opcode):                  Python Bytecode Instructions.
                                                             (line  289)
* STORE_SUBSCR (opcode):                 Python Bytecode Instructions.
                                                             (line  261)
* store() (imaplib.IMAP4 method):        IMAP4 Objects.      (line  316)
* storlines() (ftplib.FTP method):       FTP objects.        (line  246)
* str (built-in class):                  Text Sequence Type — str.
                                                             (line   45)
* str (built-in class); (see also string): Ranges.           (line  126)
* str_digits_check_threshold (sys.int_info attribute): sys — System-specific parameters and functions.
                                                             (line 1161)
* str() (in module locale):              locale — Internationalization services.
                                                             (line  493)
* strcoll() (in module locale):          locale — Internationalization services.
                                                             (line  446)
* StreamError:                           tarfile — Read and write tar archive files.
                                                             (line  213)
* StreamHandler (class in logging):      StreamHandler.      (line   11)
* StreamReader (class in asyncio):       StreamReader.       (line    6)
* StreamReader (class in codecs):        StreamReader Objects.
                                                             (line   10)
* streamreader (codecs.CodecInfo attribute): codecs — Codec registry and base classes.
                                                             (line   96)
* StreamReaderWriter (class in codecs):  StreamReaderWriter Objects.
                                                             (line   12)
* StreamRecoder (class in codecs):       StreamRecoder Objects.
                                                             (line   13)
* StreamRequestHandler (class in socketserver): Request Handler Objects.
                                                             (line   56)
* streams:                               codecs — Codec registry and base classes.
                                                             (line    8)
* StreamWriter (class in asyncio):       StreamWriter.       (line    6)
* StreamWriter (class in codecs):        StreamWriter Objects.
                                                             (line   10)
* streamwriter (codecs.CodecInfo attribute): codecs — Codec registry and base classes.
                                                             (line   96)
* StrEnum (class in enum):               Data types.         (line  437)
* strerror (C function):                 Raising exceptions. (line   60)
* strerror (OSError attribute):          Concrete exceptions.
                                                             (line  188)
* strerror() (in module os):             Process Parameters. (line  522)
* strftime() (datetime.date method):     date Objects.       (line  300)
* strftime() (datetime.datetime method): datetime Objects.   (line  753)
* strftime() (datetime.time method):     time Objects.       (line  221)
* strftime() (in module time):           Functions<5>.       (line  319)
* strict (csv.Dialect attribute):        Dialects and Formatting Parameters.
                                                             (line   88)
* STRICT (enum.FlagBoundary attribute):  Data types.         (line  715)
* strict (in module email.policy):       email policy Policy Objects.
                                                             (line  530)
* strict_domain (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line   95)
* strict_errors() (in module codecs):    Error Handlers.     (line  141)
* strict_ns_domain (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  117)
* strict_ns_set_initial_dollar (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  122)
* strict_ns_set_path (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  127)
* strict_ns_unverifiable (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  112)
* strict_rfc2965_unverifiable (http.cookiejar.DefaultCookiePolicy attribute): DefaultCookiePolicy Objects.
                                                             (line  103)
* strict; error handler's name:          Error Handlers.     (line   15)
* STRIDED (inspect.BufferFlags attribute): Buffer flags.     (line   37)
* STRIDED_RO (inspect.BufferFlags attribute): Buffer flags.  (line   39)
* STRIDES (inspect.BufferFlags attribute): Buffer flags.     (line   23)
* strides (memoryview attribute):        Memory Views.       (line  462)
* STRING (in module token):              token — Constants used with Python parse trees.
                                                             (line   54)
* string (re.Match attribute):           Match Objects.      (line  210)
* string literal:                        Literals.           (line    8)
* string_at() (in module ctypes):        Utility functions.  (line  228)
* string; __format__() (object method):  Basic customization.
                                                             (line  151)
* string; __str__() (object method):     Basic customization.
                                                             (line  129)
* string; conversion:                    Basic customization.
                                                             (line  151)
* string; conversion <1>:                Expression statements.
                                                             (line   17)
* string; format() (built-in function):  Built-in Functions. (line  786)
* string; formatted literal:             Fancier Output Formatting.
                                                             (line   93)
* string; formatted literal <1>:         String literal concatenation.
                                                             (line   24)
* string; formatted literal <2>:         String Methods<2>.  (line  966)
* string; formatting, printf:            printf-style String Formatting.
                                                             (line    6)
* string; immutable sequences:           Immutable sequences.
                                                             (line   13)
* string; interpolated literal:          Fancier Output Formatting.
                                                             (line   93)
* string; interpolated literal <1>:      String literal concatenation.
                                                             (line   24)
* string; interpolated literal <2>:      String Methods<2>.  (line  966)
* string; interpolation, printf:         printf-style String Formatting.
                                                             (line    6)
* string; item:                          Subscriptions.      (line   58)
* string; methods:                       Text Sequence Type — str.
                                                             (line   89)
* string; object representation:         Finalization and De-allocation.
                                                             (line   91)
* string; PyObject_Str (C function):     Object Protocol.    (line  357)
* string; str (built-in class):          Text Sequence Type — str.
                                                             (line   45)
* string; str() (built-in function):     Built-in Functions. (line 1881)
* string; text sequence type:            Ranges.             (line  126)
* StringIO (class in io):                Text I/O<2>.        (line  239)
* strings, documentation:                Defining Functions. (line   21)
* strings, documentation <1>:            Documentation Strings.
                                                             (line    6)
* strip_dirs() (pstats.Stats method):    The Stats Class.    (line   34)
* strip() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  442)
* strip() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  442)
* strip() (str method):                  String Methods<2>.  (line  848)
* stripspaces (curses.textpad.Textbox attribute): Textbox objects.
                                                             (line  115)
* strong reference:                      Glossary.           (line 1604)
* strptime() (datetime.datetime class method): datetime Objects.
                                                             (line  254)
* strptime() (in module time):           Functions<5>.       (line  478)
* strsignal() (in module signal):        Module contents<3>. (line  325)
* Struct (class in struct):              Classes<3>.         (line    8)
* struct_time (class in time):           Functions<5>.       (line  512)
* structmember.h:                        Member types.       (line  121)
* Structure (class in ctypes):           Structured data types.
                                                             (line   33)
* strxfrm() (in module locale):          locale — Internationalization services.
                                                             (line  453)
* STX (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   24)
* Style (class in tkinter.ttk):          Ttk Styling.        (line   20)
* Sub (class in ast):                    Expressions<2>.     (line   53)
* SUB (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line  102)
* sub() (in module operator):            operator — Standard operators as functions.
                                                             (line  157)
* sub() (in module re):                  Functions<2>.       (line  171)
* sub() (re.Pattern method):             Regular Expression Objects.
                                                             (line   97)
* subclassing; immutable types:          Basic customization.
                                                             (line    8)
* subdirs (filecmp.dircmp attribute):    The dircmp class.   (line  104)
* SubElement() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  208)
* subgroup() (BaseExceptionGroup method): Exception groups.  (line   46)
* submit() (concurrent.futures.Executor method): Executor Objects.
                                                             (line   12)
* submodule_search_locations (importlib.machinery.ModuleSpec attribute): importlib machinery – Importers and path hooks.
                                                             (line  402)
* subn() (in module re):                 Functions<2>.       (line  247)
* subn() (re.Pattern method):            Regular Expression Objects.
                                                             (line  102)
* subnet_of() (ipaddress.IPv4Network method): Network objects.
                                                             (line  215)
* subnet_of() (ipaddress.IPv6Network method): Network objects.
                                                             (line  348)
* subnets() (ipaddress.IPv4Network method): Network objects. (line  173)
* subnets() (ipaddress.IPv6Network method): Network objects. (line  344)
* Subnormal (class in decimal):          Signals.            (line   88)
* suboffsets (memoryview attribute):     Memory Views.       (line  471)
* subpad() (curses.window method):       Window Objects.     (line  529)
* subprocess_exec() (asyncio.loop method): Running subprocesses.
                                                             (line   16)
* subprocess_shell() (asyncio.loop method): Running subprocesses.
                                                             (line  118)
* SubprocessError:                       Using the subprocess Module.
                                                             (line  162)
* SubprocessProtocol (class in asyncio): Base Protocols.     (line   24)
* SubprocessTransport (class in asyncio): Transports Hierarchy.
                                                             (line   50)
* subscribe() (imaplib.IMAP4 method):    IMAP4 Objects.      (line  340)
* Subscript (class in ast):              Subscripting.       (line    6)
* subscript; assignment:                 Mutable Sequence Types.
                                                             (line   16)
* subscript; operation:                  Common Sequence Operations.
                                                             (line   21)
* subscription:                          Sequences.          (line    6)
* subscription <1>:                      Mutable sequences.  (line    6)
* subscription <2>:                      Mappings.           (line    6)
* subscription <3>:                      Subscriptions.      (line    6)
* subscription; assignment:              Assignment statements.
                                                             (line  101)
* subsequent_indent (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  215)
* substitute() (string.Template method): Template strings.   (line   40)
* subTest() (unittest.TestCase method):  Test cases.         (line  103)
* subtract() (collections.Counter method): Counter objects.  (line   93)
* subtract() (decimal.Context method):   Context objects.    (line  533)
* subtraction:                           Binary arithmetic operations.
                                                             (line   83)
* subtype (email.headerregistry.ContentTypeHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  277)
* subwin() (curses.window method):       Window Objects.     (line  536)
* successful() (multiprocessing.pool.AsyncResult method): Process Pools.
                                                             (line  219)
* suffix (pathlib.PurePath attribute):   Methods and properties.
                                                             (line  137)
* suffix_map (in module mimetypes):      mimetypes — Map filenames to MIME types.
                                                             (line  141)
* suffix_map (mimetypes.MimeTypes attribute): MimeTypes Objects.
                                                             (line   23)
* suffixes (pathlib.PurePath attribute): Methods and properties.
                                                             (line  150)
* suite:                                 Compound statements.
                                                             (line   18)
* suiteClass (unittest.TestLoader attribute): Loading and running tests.
                                                             (line  200)
* sum_list():                            Reference Count Details.
                                                             (line  143)
* sum_sequence():                        Reference Count Details.
                                                             (line  170)
* sum_sequence() <1>:                    Exceptions<21>.     (line   65)
* summarize_address_range() (in module ipaddress): Other Module Level Functions.
                                                             (line   27)
* summarize() (doctest.DocTestRunner method): DocTestRunner objects.
                                                             (line  122)
* sumprod() (in module math):            Summation and product functions.
                                                             (line   62)
* SUNDAY (in module calendar):           calendar — General calendar-related functions.
                                                             (line  445)
* super (built-in class):                Built-in Functions. (line 1915)
* super (pyclbr.Class attribute):        Class Objects<2>.   (line   42)
* supernet_of() (ipaddress.IPv4Network method): Network objects.
                                                             (line  226)
* supernet_of() (ipaddress.IPv6Network method): Network objects.
                                                             (line  350)
* supernet() (ipaddress.IPv4Network method): Network objects.
                                                             (line  199)
* supernet() (ipaddress.IPv6Network method): Network objects.
                                                             (line  346)
* supports_bytes_environ (in module os): Process Parameters. (line  528)
* supports_dir_fd (in module os):        Files and Directories.
                                                             (line 1420)
* supports_effective_ids (in module os): Files and Directories.
                                                             (line 1445)
* supports_fd (in module os):            Files and Directories.
                                                             (line 1464)
* supports_follow_symlinks (in module os): Files and Directories.
                                                             (line 1483)
* supports_unicode_filenames (in module os.path): os path — Common pathname manipulations.
                                                             (line  581)
* SupportsAbs (class in typing):         Protocols<3>.       (line    9)
* SupportsBytes (class in typing):       Protocols<3>.       (line   14)
* SupportsComplex (class in typing):     Protocols<3>.       (line   18)
* SupportsFloat (class in typing):       Protocols<3>.       (line   22)
* SupportsIndex (class in typing):       Protocols<3>.       (line   26)
* SupportsInt (class in typing):         Protocols<3>.       (line   32)
* SupportsRound (class in typing):       Protocols<3>.       (line   36)
* suppress() (in module contextlib):     Utilities.          (line  265)
* SuppressCrashReport (class in test.support): test support — Utilities for the Python test suite.
                                                             (line  754)
* surrogateescape; error handler's name: Error Handlers.     (line   15)
* surrogatepass; error handler's name:   Error Handlers.     (line   73)
* SW_HIDE (in module subprocess):        Windows Constants.  (line   23)
* SWAP (opcode):                         Python Bytecode Instructions.
                                                             (line  169)
* swap_attr() (in module test.support):  test support — Utilities for the Python test suite.
                                                             (line  373)
* swap_item() (in module test.support):  test support — Utilities for the Python test suite.
                                                             (line  390)
* swapcase() (bytearray method):         Bytes and Bytearray Operations.
                                                             (line  662)
* swapcase() (bytes method):             Bytes and Bytearray Operations.
                                                             (line  662)
* swapcase() (str method):               String Methods<2>.  (line  878)
* Symbol (class in symtable):            Examining Symbol Tables.
                                                             (line  191)
* SymbolTable (class in symtable):       Examining Symbol Tables.
                                                             (line   49)
* SymbolTableType (class in symtable):   Examining Symbol Tables.
                                                             (line    6)
* symlink_to() (pathlib.Path method):    Creating files and directories.
                                                             (line   45)
* symlink() (in module os):              Files and Directories.
                                                             (line 1506)
* symmetric_difference_update() (set method): Set Types — set frozenset.
                                                             (line  190)
* symmetric_difference() (frozenset method): Set Types — set frozenset.
                                                             (line  120)
* symmetric_difference() (set method):   Set Types — set frozenset.
                                                             (line  120)
* symtable() (in module symtable):       Generating Symbol Tables.
                                                             (line    6)
* SYMTYPE (in module tarfile):           tarfile — Read and write tar archive files.
                                                             (line  286)
* SYN (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   90)
* sync() (dbm.dumb.dumbdbm method):      dbm dumb — Portable DBM implementation.
                                                             (line   83)
* sync() (dbm.gnu.gdbm method):          dbm gnu — GNU database manager.
                                                             (line  128)
* sync() (in module os):                 Files and Directories.
                                                             (line 1555)
* sync() (shelve.Shelf method):          shelve — Python object persistence.
                                                             (line   68)
* syncdown() (curses.window method):     Window Objects.     (line  546)
* synchronization primitive:             Glossary.           (line 1619)
* synchronized() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   96)
* SyncManager (class in multiprocessing.managers): Managers. (line  150)
* syncok() (curses.window method):       Window Objects.     (line  552)
* syncup() (curses.window method):       Window Objects.     (line  557)
* syntax:                                Notation.           (line    6)
* SyntaxErr:                             Exceptions<20>.     (line   93)
* SyntaxError:                           Concrete exceptions.
                                                             (line  304)
* SyntaxWarning:                         Warnings.           (line   43)
* sys_version (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  141)
* sys.exc_info:                          Traceback objects.  (line    6)
* sys.exception:                         Traceback objects.  (line    6)
* sys.last_traceback:                    Traceback objects.  (line    6)
* sys.meta_path:                         The meta path.      (line    6)
* sys.modules:                           The module cache.   (line    6)
* sys.path:                              Path entry finders. (line    6)
* sys.path_hooks:                        Path entry finders. (line    6)
* sys.path_importer_cache:               Path entry finders. (line    6)
* sys.stderr:                            I/O objects also known as file objects.
                                                             (line    6)
* sys.stdin:                             I/O objects also known as file objects.
                                                             (line    6)
* sys.stdout:                            I/O objects also known as file objects.
                                                             (line    6)
* sysconf_names (in module os):          Miscellaneous System Information.
                                                             (line   86)
* sysconf() (in module os):              Miscellaneous System Information.
                                                             (line   76)
* syslog() (in module syslog):           syslog — Unix syslog library routines.
                                                             (line   20)
* SysLogHandler (class in logging.handlers): SysLogHandler.  (line   10)
* system_alias() (in module platform):   Cross platform.     (line  132)
* system_must_validate_cert() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  461)
* system() (in module os):               Process Management. (line  754)
* system() (in module platform):         Cross platform.     (line  122)
* SystemError:                           Concrete exceptions.
                                                             (line  366)
* SystemError (built-in exception):      Module Objects.     (line   67)
* SystemError (built-in exception) <1>:  Module Objects.     (line  103)
* SystemExit:                            Concrete exceptions.
                                                             (line  383)
* SystemExit (built-in exception):       Exceptions<2>.      (line   26)
* systemId (xml.dom.DocumentType attribute): DocumentType Objects.
                                                             (line   22)
* SystemRandom (class in random):        Alternative Generator.
                                                             (line   51)
* SystemRandom (class in secrets):       Random numbers.     (line    9)
* T_BOOL (C macro):                      Member types.       (line  121)
* T_BYTE (C macro):                      Member types.       (line  121)
* T_CHAR (C macro):                      Member types.       (line  121)
* T_DOUBLE (C macro):                    Member types.       (line  121)
* T_FLOAT (C macro):                     Member types.       (line  121)
* T_FMT (in module locale):              locale — Internationalization services.
                                                             (line  214)
* T_FMT_AMPM (in module locale):         locale — Internationalization services.
                                                             (line  220)
* T_INT (C macro):                       Member types.       (line  121)
* T_LONG (C macro):                      Member types.       (line  121)
* T_LONGLONG (C macro):                  Member types.       (line  121)
* T_NONE (C macro):                      Member types.       (line  132)
* T_OBJECT (C macro):                    Member types.       (line  126)
* T_OBJECT_EX (C macro):                 Member types.       (line  121)
* T_PYSSIZET (C macro):                  Member types.       (line  121)
* T_SHORT (C macro):                     Member types.       (line  121)
* T_STRING (C macro):                    Member types.       (line  121)
* T_STRING_INPLACE (C macro):            Member types.       (line  121)
* T_UBYTE (C macro):                     Member types.       (line  121)
* T_UINT (C macro):                      Member types.       (line  121)
* T_ULONG (C macro):                     Member types.       (line  121)
* T_ULONGULONG (C macro):                Member types.       (line  121)
* T_USHORT (C macro):                    Member types.       (line  121)
* tab:                                   Indentation.        (line    6)
* TAB (in module curses.ascii):          curses ascii — Utilities for ASCII characters.
                                                             (line   45)
* tab() (tkinter.ttk.Notebook method):   ttk Notebook.       (line   62)
* TabError:                              Concrete exceptions.
                                                             (line  361)
* tabs() (tkinter.ttk.Notebook method):  ttk Notebook.       (line   71)
* tabsize (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  172)
* tag (xml.etree.ElementTree.Element attribute): Element Objects.
                                                             (line   16)
* tag_bind() (tkinter.ttk.Treeview method): ttk Treeview.    (line  293)
* tag_configure() (tkinter.ttk.Treeview method): ttk Treeview.
                                                             (line  299)
* tag_has() (tkinter.ttk.Treeview method): ttk Treeview.     (line  309)
* tagName (xml.dom.Element attribute):   Element Objects<2>. (line    9)
* tail (xml.etree.ElementTree.Element attribute): Element Objects.
                                                             (line   21)
* take_snapshot() (in module tracemalloc): Functions<11>.    (line  109)
* takewhile() (in module itertools):     Itertool Functions. (line  567)
* tan() (in module cmath):               Trigonometric functions<2>.
                                                             (line   31)
* tan() (in module math):                Trigonometric functions.
                                                             (line   38)
* tanh() (in module cmath):              Hyperbolic functions<2>.
                                                             (line   31)
* tanh() (in module math):               Hyperbolic functions.
                                                             (line   29)
* tar_filter() (in module tarfile):      Default named filters.
                                                             (line   15)
* TarError:                              tarfile — Read and write tar archive files.
                                                             (line  199)
* TarFile (class in tarfile):            TarFile Objects.    (line   22)
* tarfile command line option; -c:       Command-line options<3>.
                                                             (line   11)
* tarfile command line option; -create:  Command-line options<3>.
                                                             (line   11)
* tarfile command line option; -e:       Command-line options<3>.
                                                             (line   16)
* tarfile command line option; -extract: Command-line options<3>.
                                                             (line   16)
* tarfile command line option; -filter:  Command-line options<3>.
                                                             (line   31)
* tarfile command line option; -l:       Command-line options<3>.
                                                             (line    6)
* tarfile command line option; -list:    Command-line options<3>.
                                                             (line    6)
* tarfile command line option; -t:       Command-line options<3>.
                                                             (line   22)
* tarfile command line option; -test:    Command-line options<3>.
                                                             (line   22)
* tarfile command line option; -v:       Command-line options<3>.
                                                             (line   27)
* tarfile command line option; -verbose: Command-line options<3>.
                                                             (line   27)
* target:                                Assignment statements.
                                                             (line   27)
* target (xml.dom.ProcessingInstruction attribute): ProcessingInstruction Objects.
                                                             (line    9)
* target; list:                          Assignment statements.
                                                             (line   27)
* target; list <1>:                      The for statement.  (line    6)
* target; list; assignment:              Assignment statements.
                                                             (line   35)
* TarInfo (class in tarfile):            TarInfo Objects.    (line   33)
* tarinfo (tarfile.FilterError attribute): tarfile — Read and write tar archive files.
                                                             (line  233)
* Task (class in asyncio):               Task object.        (line    6)
* task_done() (asyncio.Queue method):    Queue.              (line  117)
* task_done() (multiprocessing.JoinableQueue method): Pipes and Queues.
                                                             (line  264)
* task_done() (queue.Queue method):      Queue Objects.      (line   73)
* TaskGroup (class in asyncio):          Task groups.        (line    9)
* tau (in module cmath):                 Constants<3>.       (line   14)
* tau (in module math):                  Constants<2>.       (line   14)
* tb_frame (traceback attribute):        Traceback objects.  (line   31)
* tb_frame (traceback attribute) <1>:    Traceback objects.  (line   33)
* tb_lasti (traceback attribute):        Traceback objects.  (line   31)
* tb_lasti (traceback attribute) <1>:    Traceback objects.  (line   44)
* tb_lineno (traceback attribute):       Traceback objects.  (line   31)
* tb_lineno (traceback attribute) <1>:   Traceback objects.  (line   41)
* tb_locals (unittest.TestResult attribute): Loading and running tests.
                                                             (line  308)
* tb_next (traceback attribute):         Traceback objects.  (line   52)
* tb_next (traceback attribute) <1>:     Traceback objects.  (line   52)
* tbreak (pdb command):                  Debugger commands.  (line  121)
* tcdrain() (in module termios):         termios — POSIX style tty control.
                                                             (line   65)
* tcflow() (in module termios):          termios — POSIX style tty control.
                                                             (line   76)
* tcflush() (in module termios):         termios — POSIX style tty control.
                                                             (line   70)
* tcgetattr() (in module termios):       termios — POSIX style tty control.
                                                             (line   28)
* tcgetpgrp() (in module os):            File Descriptor Operations.
                                                             (line  884)
* tcgetwinsize() (in module termios):    termios — POSIX style tty control.
                                                             (line   83)
* Tcl() (in module tkinter):             Tkinter Modules.    (line   92)
* TCPServer (class in socketserver):     socketserver — A framework for network servers.
                                                             (line   20)
* TCSADRAIN (in module termios):         termios — POSIX style tty control.
                                                             (line   50)
* TCSAFLUSH (in module termios):         termios — POSIX style tty control.
                                                             (line   54)
* TCSANOW (in module termios):           termios — POSIX style tty control.
                                                             (line   46)
* tcsendbreak() (in module termios):     termios — POSIX style tty control.
                                                             (line   59)
* tcsetattr() (in module termios):       termios — POSIX style tty control.
                                                             (line   39)
* tcsetpgrp() (in module os):            File Descriptor Operations.
                                                             (line  891)
* tcsetwinsize() (in module termios):    termios — POSIX style tty control.
                                                             (line   91)
* tearDown() (unittest.TestCase method): Test cases.         (line   39)
* tearDownClass() (unittest.TestCase method): Test cases.    (line   67)
* tearDownModule() (in module unittest): setUpModule and tearDownModule.
                                                             (line    6)
* tee() (in module itertools):           Itertool Functions. (line  586)
* teleport() (in module turtle):         Turtle motion.      (line  104)
* tell() (io.IOBase method):             I/O Base Classes.   (line  134)
* tell() (io.TextIOBase method):         Text I/O<2>.        (line   87)
* tell() (io.TextIOWrapper method):      Text I/O<2>.        (line  233)
* tell() (mmap.mmap method):             mmap — Memory-mapped file support.
                                                             (line  317)
* tell() (sqlite3.Blob method):          Blob objects.       (line   59)
* tell() (wave.Wave_read method):        Wave_read Objects.  (line   87)
* tell() (wave.Wave_write method):       Wave_write Objects. (line  100)
* TEMP:                                  Redirection of local data registry and temporary paths.
                                                             (line    7)
* TEMP <1>:                              tempfile — Generate temporary files and directories.
                                                             (line  329)
* temp_cwd() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  134)
* temp_dir() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  149)
* temp_umask() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  159)
* tempdir (in module tempfile):          tempfile — Generate temporary files and directories.
                                                             (line  376)
* Template (class in string):            Template strings.   (line   35)
* template (string.Template attribute):  Template strings.   (line   84)
* temporary (bdb.Breakpoint attribute):  bdb — Debugger framework.
                                                             (line   90)
* temporary; file:                       tempfile — Generate temporary files and directories.
                                                             (line    8)
* temporary; file name:                  tempfile — Generate temporary files and directories.
                                                             (line    8)
* TemporaryDirectory (class in tempfile): tempfile — Generate temporary files and directories.
                                                             (line  184)
* TemporaryFile() (in module tempfile):  tempfile — Generate temporary files and directories.
                                                             (line   28)
* teredo (ipaddress.IPv6Address attribute): Address objects. (line  320)
* TERM:                                  Functions<6>.       (line  484)
* TERM <1>:                              Functions<6>.       (line  510)
* termattrs() (in module curses):        Functions<6>.       (line  502)
* terminal_size (class in os):           Querying the size of a terminal.
                                                             (line   25)
* terminate() (asyncio.subprocess.Process method): Interacting with Subprocesses.
                                                             (line   96)
* terminate() (asyncio.SubprocessTransport method): Subprocess Transports.
                                                             (line   49)
* terminate() (multiprocessing.pool.Pool method): Process Pools.
                                                             (line  180)
* terminate() (multiprocessing.Process method): Process and exceptions.
                                                             (line  204)
* terminate() (subprocess.Popen method): Popen Objects.      (line   93)
* termination model:                     Exceptions<2>.      (line   20)
* terminator (logging.StreamHandler attribute): StreamHandler.
                                                             (line   47)
* termname() (in module curses):         Functions<6>.       (line  508)
* ternary; operator:                     Conditional expressions.
                                                             (line    6)
* ternaryfunc (C type):                  Slot Type typedefs. (line  122)
* test (doctest.DocTestFailure attribute): Debugging.        (line  195)
* test (doctest.UnexpectedException attribute): Debugging.   (line  216)
* TEST_DATA_DIR (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  136)
* TEST_HOME_DIR (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  132)
* TEST_HTTP_URL (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  170)
* TEST_SUPPORT_DIR (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  128)
* TestCase (class in unittest):          Test cases.         (line    6)
* TestFailed:                            test support — Utilities for the Python test suite.
                                                             (line   16)
* testfile() (in module doctest):        Basic API.          (line   12)
* TESTFN (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   18)
* TESTFN_NONASCII (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   24)
* TESTFN_UNDECODABLE (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   38)
* TESTFN_UNENCODABLE (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   32)
* TESTFN_UNICODE (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line   44)
* TestLoader (class in unittest):        Loading and running tests.
                                                             (line    6)
* testMethodPrefix (unittest.TestLoader attribute): Loading and running tests.
                                                             (line  186)
* testmod() (in module doctest):         Basic API.          (line   90)
* testNamePatterns (unittest.TestLoader attribute): Loading and running tests.
                                                             (line  208)
* TestResult (class in unittest):        Loading and running tests.
                                                             (line  225)
* TestResults (class in doctest):        TestResults objects.
                                                             (line    6)
* testsource() (in module doctest):      Debugging.          (line  106)
* testsRun (unittest.TestResult attribute): Loading and running tests.
                                                             (line  286)
* TestSuite (class in unittest):         Grouping tests.     (line    6)
* testzip() (zipfile.ZipFile method):    ZipFile objects.    (line  261)
* Text (class in typing):                Aliases to other concrete types.
                                                             (line   21)
* text (SyntaxError attribute):          Concrete exceptions.
                                                             (line  331)
* text (traceback.TracebackException attribute): TracebackException Objects.
                                                             (line  106)
* text (xml.etree.ElementTree.Element attribute): Element Objects.
                                                             (line   21)
* text encoding:                         Glossary.           (line 1632)
* text file:                             Glossary.           (line 1645)
* text mode:                             Built-in Functions. (line 1464)
* text_encoding() (in module io):        High-level Module Interface.
                                                             (line   38)
* text_factory (sqlite3.Connection attribute): Connection objects.
                                                             (line  806)
* Textbox (class in curses.textpad):     Textbox objects.    (line    8)
* TextCalendar (class in calendar):      calendar — General calendar-related functions.
                                                             (line  149)
* textdomain() (in module gettext):      GNU gettext API.    (line   26)
* textdomain() (in module locale):       Access to message catalogs.
                                                             (line   12)
* textinput() (in module turtle):        Input methods.      (line    6)
* TextIO (class in typing):              ABCs for working with IO.
                                                             (line    6)
* TextIOBase (class in io):              Text I/O<2>.        (line    6)
* TextIOWrapper (class in io):           Text I/O<2>.        (line   98)
* TextTestResult (class in unittest):    Loading and running tests.
                                                             (line  443)
* TextTestRunner (class in unittest):    Loading and running tests.
                                                             (line  460)
* TextWrapper (class in textwrap):       textwrap — Text wrapping and filling.
                                                             (line  139)
* TFD_CLOEXEC (in module os):            Timer File Descriptors.
                                                             (line  202)
* TFD_NONBLOCK (in module os):           Timer File Descriptors.
                                                             (line  191)
* TFD_TIMER_ABSTIME (in module os):      Timer File Descriptors.
                                                             (line  212)
* TFD_TIMER_CANCEL_ON_SET (in module os): Timer File Descriptors.
                                                             (line  223)
* theme_create() (tkinter.ttk.Style method): Ttk Styling.    (line  260)
* theme_names() (tkinter.ttk.Style method): Ttk Styling.     (line  308)
* theme_settings() (tkinter.ttk.Style method): Ttk Styling.  (line  270)
* theme_use() (tkinter.ttk.Style method): Ttk Styling.       (line  312)
* THOUSEP (in module locale):            locale — Internationalization services.
                                                             (line  283)
* Thread (class in threading):           Thread objects.     (line   56)
* thread_info (in module sys):           sys — System-specific parameters and functions.
                                                             (line 1916)
* thread_time_ns() (in module time):     Functions<5>.       (line  631)
* thread_time() (in module time):        Functions<5>.       (line  613)
* thread-safe:                           Glossary.           (line 1657)
* thread() (imaplib.IMAP4 method):       IMAP4 Objects.      (line  344)
* ThreadedChildWatcher (class in asyncio): Process Watchers. (line   90)
* threading_cleanup() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   31)
* threading_setup() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   37)
* ThreadingHTTPServer (class in http.server): http server — HTTP servers.
                                                             (line   37)
* ThreadingMixIn (class in socketserver): Server Creation Notes.
                                                             (line   27)
* ThreadingMock (class in unittest.mock): The Mock Class.    (line  951)
* ThreadingTCPServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ThreadingUDPServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ThreadingUnixDatagramServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ThreadingUnixStreamServer (class in socketserver): Server Creation Notes.
                                                             (line   66)
* ThreadPool (class in multiprocessing.pool): The multiprocessing dummy module.
                                                             (line   14)
* ThreadPoolExecutor (class in concurrent.futures): ThreadPoolExecutor.
                                                             (line   41)
* threads; POSIX:                        _thread — Low-level threading API.
                                                             (line   16)
* threadsafety (in module sqlite3):      Module constants.   (line   88)
* throw() (coroutine method):            Coroutine Objects.  (line   33)
* throw() (generator method):            Generator-iterator methods.
                                                             (line   37)
* THURSDAY (in module calendar):         calendar — General calendar-related functions.
                                                             (line  445)
* ticket_lifetime_hint (ssl.SSLSession attribute): SSL session.
                                                             (line   18)
* tigetflag() (in module curses):        Functions<6>.       (line  513)
* tigetnum() (in module curses):         Functions<6>.       (line  520)
* tigetstr() (in module curses):         Functions<6>.       (line  527)
* TILDE (in module token):               token — Constants used with Python parse trees.
                                                             (line  248)
* tilt() (in module turtle):             Appearance.         (line  101)
* tiltangle() (in module turtle):        Appearance.         (line  117)
* time (class in datetime):              time Objects.       (line   10)
* time (ssl.SSLSession attribute):       SSL session.        (line   14)
* time (uuid.UUID attribute):            uuid — UUID objects according to RFC 4122.
                                                             (line  122)
* time_hi_version (uuid.UUID attribute): uuid — UUID objects according to RFC 4122.
                                                             (line  110)
* time_low (uuid.UUID attribute):        uuid — UUID objects according to RFC 4122.
                                                             (line  104)
* time_mid (uuid.UUID attribute):        uuid — UUID objects according to RFC 4122.
                                                             (line  107)
* time_ns() (in module time):            Functions<5>.       (line  606)
* time() (asyncio.loop method):          Scheduling delayed callbacks.
                                                             (line   64)
* time() (datetime.datetime method):     datetime Objects.   (line  444)
* time() (in module time):               Functions<5>.       (line  570)
* Time2Internaldate() (in module imaplib): imaplib — IMAP4 protocol client.
                                                             (line  127)
* timedelta (class in datetime):         timedelta Objects.  (line    9)
* TimedRotatingFileHandler (class in logging.handlers): TimedRotatingFileHandler.
                                                             (line   10)
* timegm() (in module calendar):         calendar — General calendar-related functions.
                                                             (line  417)
* timeit command line option; -h:        Command-Line Interface<3>.
                                                             (line   44)
* timeit command line option; -help:     Command-Line Interface<3>.
                                                             (line   44)
* timeit command line option; -n:        Command-Line Interface<3>.
                                                             (line   13)
* timeit command line option; -number:   Command-Line Interface<3>.
                                                             (line   13)
* timeit command line option; -p:        Command-Line Interface<3>.
                                                             (line   25)
* timeit command line option; -process:  Command-Line Interface<3>.
                                                             (line   25)
* timeit command line option; -r:        Command-Line Interface<3>.
                                                             (line   17)
* timeit command line option; -repeat:   Command-Line Interface<3>.
                                                             (line   17)
* timeit command line option; -s:        Command-Line Interface<3>.
                                                             (line   21)
* timeit command line option; -setup:    Command-Line Interface<3>.
                                                             (line   21)
* timeit command line option; -u:        Command-Line Interface<3>.
                                                             (line   33)
* timeit command line option; -unit:     Command-Line Interface<3>.
                                                             (line   33)
* timeit command line option; -v:        Command-Line Interface<3>.
                                                             (line   40)
* timeit command line option; -verbose:  Command-Line Interface<3>.
                                                             (line   40)
* timeit() (in module timeit):           Python Interface.   (line    8)
* timeit() (timeit.Timer method):        Python Interface.   (line   71)
* timeout:                               Exceptions<15>.     (line   40)
* Timeout (class in asyncio):            Timeouts.           (line   50)
* timeout (socketserver.BaseServer attribute): Server Objects.
                                                             (line  117)
* timeout (ssl.SSLSession attribute):    SSL session.        (line   16)
* timeout (subprocess.TimeoutExpired attribute): Using the subprocess Module.
                                                             (line  177)
* timeout_at() (in module asyncio):      Timeouts.           (line  102)
* TIMEOUT_MAX (in module _thread):       _thread — Low-level threading API.
                                                             (line  135)
* TIMEOUT_MAX (in module threading):     Reference<2>.       (line  184)
* timeout() (curses.window method):      Window Objects.     (line  562)
* timeout() (in module asyncio):         Timeouts.           (line    6)
* TimeoutError:                          OS exceptions.      (line  112)
* TimeoutError <1>:                      Process and exceptions.
                                                             (line  276)
* TimeoutError <2>:                      Exception classes.  (line   10)
* TimeoutError <3>:                      Exceptions<13>.     (line   10)
* TimeoutExpired:                        Using the subprocess Module.
                                                             (line  168)
* Timer (class in threading):            Timer objects.      (line   25)
* Timer (class in timeit):               Python Interface.   (line   41)
* timerfd_create() (in module os):       Timer File Descriptors.
                                                             (line   11)
* timerfd_gettime_ns() (in module os):   Timer File Descriptors.
                                                             (line  182)
* timerfd_gettime() (in module os):      Timer File Descriptors.
                                                             (line  162)
* timerfd_settime_ns() (in module os):   Timer File Descriptors.
                                                             (line  151)
* timerfd_settime() (in module os):      Timer File Descriptors.
                                                             (line   83)
* TimerHandle (class in asyncio):        Callback handles.   (line   29)
* times() (in module os):                Process Management. (line  790)
* TIMESTAMP (py_compile.PycInvalidationMode attribute): py_compile — Compile Python source files.
                                                             (line  102)
* timestamp() (datetime.datetime method): datetime Objects.  (line  598)
* timetuple() (datetime.date method):    date Objects.       (line  210)
* timetuple() (datetime.datetime method): datetime Objects.  (line  552)
* timetz() (datetime.datetime method):   datetime Objects.   (line  453)
* timezone (class in datetime):          timezone Objects.   (line   14)
* timezone (in module time):             Timezone Constants. (line   17)
* title() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  687)
* title() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  687)
* title() (in module turtle):            Methods specific to Screen not inherited from TurtleScreen.
                                                             (line   49)
* title() (str method):                  String Methods<2>.  (line  884)
* Tk:                                    Graphical user interfaces with Tk.
                                                             (line    6)
* Tk (class in tkinter):                 Tkinter Modules.    (line   13)
* tk (tkinter.Tk attribute):             Tkinter Modules.    (line   68)
* Tk Option Data Types:                  Tk Option Data Types.
                                                             (line    6)
* Tkinter:                               Graphical user interfaces with Tk.
                                                             (line    6)
* TLS:                                   ssl — TLS/SSL wrapper for socket objects.
                                                             (line    8)
* TLSv1 (ssl.TLSVersion attribute):      Constants<9>.       (line  573)
* TLSv1_1 (ssl.TLSVersion attribute):    Constants<9>.       (line  575)
* TLSv1_2 (ssl.TLSVersion attribute):    Constants<9>.       (line  577)
* TLSv1_3 (ssl.TLSVersion attribute):    Constants<9>.       (line  579)
* TLSVersion (class in ssl):             Constants<9>.       (line  555)
* tm_gmtoff (time.struct_time attribute): Functions<5>.      (line  555)
* tm_hour (time.struct_time attribute):  Functions<5>.       (line  532)
* tm_isdst (time.struct_time attribute): Functions<5>.       (line  549)
* tm_mday (time.struct_time attribute):  Functions<5>.       (line  529)
* tm_min (time.struct_time attribute):   Functions<5>.       (line  535)
* tm_mon (time.struct_time attribute):   Functions<5>.       (line  526)
* tm_sec (time.struct_time attribute):   Functions<5>.       (line  538)
* tm_wday (time.struct_time attribute):  Functions<5>.       (line  543)
* tm_yday (time.struct_time attribute):  Functions<5>.       (line  546)
* tm_year (time.struct_time attribute):  Functions<5>.       (line  523)
* tm_zone (time.struct_time attribute):  Functions<5>.       (line  552)
* TMP:                                   tempfile — Generate temporary files and directories.
                                                             (line  331)
* TMPDIR:                                Library<8>.         (line  116)
* TMPDIR <1>:                            Tests<29>.          (line   68)
* TMPDIR <2>:                            tempfile — Generate temporary files and directories.
                                                             (line  327)
* TO_BOOL (opcode):                      Python Bytecode Instructions.
                                                             (line  226)
* to_bytes() (int method):               Additional Methods on Integer Types.
                                                             (line   56)
* to_eng_string() (decimal.Context method): Context objects. (line  537)
* to_eng_string() (decimal.Decimal method): Decimal objects. (line  570)
* to_integral_exact() (decimal.Context method): Context objects.
                                                             (line  547)
* to_integral_exact() (decimal.Decimal method): Decimal objects.
                                                             (line  589)
* to_integral_value() (decimal.Decimal method): Decimal objects.
                                                             (line  597)
* to_integral() (decimal.Decimal method): Decimal objects.   (line  583)
* to_sci_string() (decimal.Context method): Context objects. (line  551)
* to_thread() (in module asyncio):       Running in threads. (line    6)
* ToASCII() (in module encodings.idna):  encodings idna — Internationalized Domain Names in Applications.
                                                             (line   54)
* tobuf() (tarfile.TarInfo method):      TarInfo Objects.    (line   49)
* tobytes() (array.array method):        array — Efficient arrays of numeric values.
                                                             (line  236)
* tobytes() (memoryview method):         Memory Views.       (line  162)
* today() (datetime.date class method):  date Objects.       (line   29)
* today() (datetime.datetime class method): datetime Objects.
                                                             (line   47)
* tofile() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  245)
* tok_name (in module token):            token — Constants used with Python parse trees.
                                                             (line   25)
* token:                                 Lexical analysis.   (line    6)
* token <1>:                             Glossary.           (line 1670)
* Token (class in contextvars):          Context Variables.  (line   77)
* token (shlex.shlex attribute):         shlex Objects.      (line  173)
* token_bytes() (in module secrets):     Generating tokens.  (line   10)
* token_hex() (in module secrets):       Generating tokens.  (line   20)
* token_urlsafe() (in module secrets):   Generating tokens.  (line   31)
* TokenError:                            Tokenizing Input.   (line  103)
* tokenize command line option; -e:      Command-Line Usage<6>.
                                                             (line   19)
* tokenize command line option; -exact:  Command-Line Usage<6>.
                                                             (line   19)
* tokenize command line option; -h:      Command-Line Usage<6>.
                                                             (line   15)
* tokenize command line option; -help:   Command-Line Usage<6>.
                                                             (line   15)
* tokenize() (in module tokenize):       Tokenizing Input.   (line    8)
* tolist() (array.array method):         array — Efficient arrays of numeric values.
                                                             (line  250)
* tolist() (memoryview method):          Memory Views.       (line  205)
* TOMLDecodeError:                       tomllib — Parse TOML files.
                                                             (line   60)
* toordinal() (datetime.date method):    date Objects.       (line  225)
* toordinal() (datetime.datetime method): datetime Objects.  (line  593)
* top_panel() (in module curses.panel):  Functions<7>.       (line   19)
* top() (curses.panel.Panel method):     Panel Objects.      (line   53)
* top() (poplib.POP3 method):            POP3 Objects.       (line   87)
* TopologicalSorter (class in graphlib): graphlib — Functionality to operate with graph-like structures.
                                                             (line   10)
* toprettyxml() (xml.dom.minidom.Node method): DOM Objects.  (line   72)
* toreadonly() (memoryview method):      Memory Views.       (line  221)
* tostring() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  221)
* tostringlist() (in module xml.etree.ElementTree): Functions<9>.
                                                             (line  243)
* total_changes (sqlite3.Connection attribute): Connection objects.
                                                             (line  816)
* total_nframe (tracemalloc.Traceback attribute): Traceback. (line   28)
* total_ordering() (in module functools): functools — Higher-order functions and operations on callable objects.
                                                             (line  270)
* total_seconds() (datetime.timedelta method): timedelta Objects.
                                                             (line  251)
* total() (collections.Counter method):  Counter objects.    (line  112)
* touch() (pathlib.Path method):         Creating files and directories.
                                                             (line    6)
* touchline() (curses.window method):    Window Objects.     (line  572)
* touchwin() (curses.window method):     Window Objects.     (line  579)
* tounicode() (array.array method):      array — Efficient arrays of numeric values.
                                                             (line  254)
* ToUnicode() (in module encodings.idna): encodings idna — Internationalized Domain Names in Applications.
                                                             (line   59)
* towards() (in module turtle):          Tell Turtle’s state.
                                                             (line   15)
* toxml() (xml.dom.minidom.Node method): DOM Objects.        (line   52)
* tparm() (in module curses):            Functions<6>.       (line  534)
* Trace (class in trace):                Programmatic Interface.
                                                             (line    6)
* Trace (class in tracemalloc):          Trace.              (line    6)
* trace command line option; -c:         Main options.       (line   12)
* trace command line option; -C:         Modifiers.          (line   11)
* trace command line option; -count:     Main options.       (line   12)
* trace command line option; -coverdir:  Modifiers.          (line   11)
* trace command line option; -f:         Modifiers.          (line    6)
* trace command line option; -file:      Modifiers.          (line    6)
* trace command line option; -g:         Modifiers.          (line   33)
* trace command line option; -help:      Command-Line Usage<3>.
                                                             (line   15)
* trace command line option; -ignore-dir: Filters.           (line   14)
* trace command line option; -ignore-module: Filters.        (line    8)
* trace command line option; -l:         Main options.       (line   23)
* trace command line option; -listfuncs: Main options.       (line   23)
* trace command line option; -m:         Modifiers.          (line   17)
* trace command line option; -missing:   Modifiers.          (line   17)
* trace command line option; -no-report: Modifiers.          (line   27)
* trace command line option; -r:         Main options.       (line   27)
* trace command line option; -R:         Modifiers.          (line   27)
* trace command line option; -report:    Main options.       (line   27)
* trace command line option; -s:         Modifiers.          (line   22)
* trace command line option; -summary:   Modifiers.          (line   22)
* trace command line option; -t:         Main options.       (line   19)
* trace command line option; -T:         Main options.       (line   33)
* trace command line option; -timing:    Modifiers.          (line   33)
* trace command line option; -trace:     Main options.       (line   19)
* trace command line option; -trackcalls: Main options.      (line   33)
* trace command line option; -version:   Command-Line Usage<3>.
                                                             (line   19)
* trace function:                        Reference<2>.       (line  116)
* trace function <1>:                    Reference<2>.       (line  132)
* trace function <2>:                    sys — System-specific parameters and functions.
                                                             (line  942)
* trace function <3>:                    sys — System-specific parameters and functions.
                                                             (line 1604)
* trace_dispatch() (bdb.Bdb method):     bdb — Debugger framework.
                                                             (line  159)
* trace() (in module inspect):           The interpreter stack.
                                                             (line  184)
* Traceback (class in inspect):          The interpreter stack.
                                                             (line   55)
* Traceback (class in tracemalloc):      Traceback.          (line    6)
* traceback (tracemalloc.Statistic attribute): Statistic.    (line   23)
* traceback (tracemalloc.StatisticDiff attribute): StatisticDiff.
                                                             (line   38)
* traceback (tracemalloc.Trace attribute): Trace.            (line   27)
* traceback_limit (tracemalloc.Snapshot attribute): Snapshot.
                                                             (line   83)
* traceback_limit (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  220)
* TracebackException (class in traceback): TracebackException Objects.
                                                             (line   15)
* tracebacklimit (in module sys):        sys — System-specific parameters and functions.
                                                             (line 1952)
* TracebackType (class in types):        Standard Interpreter Types.
                                                             (line  186)
* tracer() (in module turtle):           Animation control.  (line   23)
* traces (tracemalloc.Snapshot attribute): Snapshot.         (line   89)
* trailing; comma:                       Expression lists.   (line   29)
* transfercmd() (ftplib.FTP method):     FTP objects.        (line  256)
* transient_internet() (in module test.support.socket_helper): test support socket_helper — Utilities for socket tests.
                                                             (line   64)
* translate() (bytearray method):        Bytes and Bytearray Operations.
                                                             (line  265)
* translate() (bytes method):            Bytes and Bytearray Operations.
                                                             (line  265)
* translate() (in module fnmatch):       fnmatch — Unix filename pattern matching.
                                                             (line   82)
* translate() (in module glob):          glob — Unix style pathname pattern expansion.
                                                             (line  112)
* translate() (str method):              String Methods<2>.  (line  920)
* translation() (in module gettext):     Class-based API.    (line   43)
* transport (asyncio.StreamWriter attribute): StreamWriter.  (line   60)
* Transport (class in asyncio):          Transports Hierarchy.
                                                             (line   29)
* Transport Layer Security:              ssl — TLS/SSL wrapper for socket objects.
                                                             (line    8)
* traps (decimal.Context attribute):     Context objects.    (line  133)
* Traversable (class in importlib.abc):  importlib abc – Abstract base classes related to import.
                                                             (line  506)
* Traversable (class in importlib.resources.abc): importlib resources abc – Abstract base classes for resources.
                                                             (line   89)
* TraversableResources (class in importlib.abc): importlib abc – Abstract base classes related to import.
                                                             (line  561)
* TraversableResources (class in importlib.resources.abc): importlib resources abc – Abstract base classes for resources.
                                                             (line  161)
* traverseproc (C type):                 Supporting Cyclic Garbage Collection.
                                                             (line  165)
* TreeBuilder (class in xml.etree.ElementTree): TreeBuilder Objects.
                                                             (line    6)
* Treeview (class in tkinter.ttk):       ttk Treeview.       (line    6)
* triangular() (in module random):       Real-valued distributions.
                                                             (line   25)
* tries (doctest.DocTestRunner attribute): DocTestRunner objects.
                                                             (line  134)
* triple-quoted string:                  String and Bytes literals.
                                                             (line   36)
* triple-quoted string <1>:              Glossary.           (line 1680)
* True:                                  numbers Integral.   (line   27)
* true:                                  Truth Value Testing.
                                                             (line   10)
* True <1>:                              Truth Value Testing.
                                                             (line   23)
* True <2>:                              Boolean Type - bool.
                                                             (line    9)
* True (built-in variable):              Built-in Constants. (line   13)
* truediv() (in module operator):        operator — Standard operators as functions.
                                                             (line  162)
* trunc() (in module math):              Numeric Types — int float complex.
                                                             (line  106)
* trunc() (in module math) <1>:          Floating point arithmetic.
                                                             (line   87)
* truncate() (in module os):             Files and Directories.
                                                             (line 1563)
* truncate() (io.IOBase method):         I/O Base Classes.   (line  138)
* truth; value:                          Truth Value Testing.
                                                             (line    6)
* truth() (in module operator):          operator — Standard operators as functions.
                                                             (line   57)
* Try (class in ast):                    Control flow.       (line  130)
* TryStar (class in ast):                Control flow.       (line  173)
* ttk:                                   tkinter ttk — Tk themed widgets.
                                                             (line    8)
* tty; I/O control:                      termios — POSIX style tty control.
                                                             (line    6)
* ttyname() (in module os):              File Descriptor Operations.
                                                             (line  899)
* TUESDAY (in module calendar):          calendar — General calendar-related functions.
                                                             (line  445)
* tuple (built-in class):                Tuples.             (line   12)
* Tuple (class in ast):                  Literals<3>.        (line   66)
* Tuple (in module typing):              Aliases to built-in types.
                                                             (line   50)
* Turtle (class in turtle):              Public classes.     (line   16)
* turtles() (in module turtle):          Settings and special methods.
                                                             (line   97)
* TurtleScreen (class in turtle):        Public classes.     (line   22)
* turtlesize() (in module turtle):       Appearance.         (line   52)
* type:                                  The standard type hierarchy.
                                                             (line    6)
* type <1>:                              Glossary.           (line 1690)
* type (built-in class):                 Built-in Functions. (line 2005)
* Type (class in typing):                Aliases to built-in types.
                                                             (line   61)
* type (optparse.Option attribute):      Option attributes.  (line   27)
* type (socket.socket attribute):        Socket Objects.     (line  615)
* type (tarfile.TarInfo attribute):      TarInfo Objects.    (line   86)
* type (urllib.request.Request attribute): Request Objects.  (line   21)
* type alias:                            Glossary.           (line 1697)
* type hint:                             Glossary.           (line 1719)
* type of an object:                     Objects values and types.
                                                             (line   10)
* type parameters:                       Type parameter lists.
                                                             (line   11)
* TYPE_ALIAS (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   31)
* type_check_only() (in module typing):  Functions and decorators.
                                                             (line  411)
* TYPE_CHECKER (optparse.Option attribute): Adding new types.
                                                             (line   16)
* TYPE_CHECKING (in module typing):      Constant.           (line    6)
* type_comment (ast.arg attribute):      Function and class definitions.
                                                             (line   74)
* type_comment (ast.Assign attribute):   Statements.         (line   15)
* type_comment (ast.For attribute):      Control flow.       (line   54)
* type_comment (ast.FunctionDef attribute): Function and class definitions.
                                                             (line   25)
* type_comment (ast.With attribute):     Control flow.       (line  236)
* TYPE_COMMENT (in module token):        token — Constants used with Python parse trees.
                                                             (line  145)
* TYPE_IGNORE (in module token):         token — Constants used with Python parse trees.
                                                             (line  138)
* TYPE_PARAMETERS (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   35)
* TYPE_VARIABLE (symtable.SymbolTableType attribute): Examining Symbol Tables.
                                                             (line   40)
* type; hierarchy:                       The standard type hierarchy.
                                                             (line    6)
* typeahead() (in module curses):        Functions<6>.       (line  542)
* TypeAlias (class in ast):              Statements.         (line  162)
* TypeAlias (in module typing):          Special types.      (line  198)
* TypeAliasType (class in typing):       Building generic types and type aliases.
                                                             (line  492)
* typecode (array.array attribute):      array — Efficient arrays of numeric values.
                                                             (line  113)
* typecodes (in module array):           array — Efficient arrays of numeric values.
                                                             (line   82)
* TYPED_ACTIONS (optparse.Option attribute): Adding new actions.
                                                             (line   38)
* typed_subpart_iterator() (in module email.iterators): email iterators Iterators.
                                                             (line   26)
* TypedDict (class in typing):           Other special directives.
                                                             (line  241)
* TypeError:                             Concrete exceptions.
                                                             (line  410)
* TypeGuard (in module typing):          Special forms.      (line  526)
* TypeIgnore (class in ast):             Type annotations.   (line    6)
* TypeIs (in module typing):             Special forms.      (line  436)
* TYPES (optparse.Option attribute):     Adding new types.   (line   11)
* types_map (in module mimetypes):       mimetypes — Map filenames to MIME types.
                                                             (line  153)
* types_map (mimetypes.MimeTypes attribute): MimeTypes Objects.
                                                             (line   39)
* types_map_inv (mimetypes.MimeTypes attribute): MimeTypes Objects.
                                                             (line   47)
* types, internal:                       Internal types.     (line    6)
* TypeVar (class in ast):                Type parameters.    (line    9)
* TypeVar (class in typing):             Building generic types and type aliases.
                                                             (line   54)
* TypeVarTuple (class in ast):           Type parameters.    (line   68)
* TypeVarTuple (class in typing):        Building generic types and type aliases.
                                                             (line  217)
* TZ:                                    Functions<5>.       (line  641)
* TZ <1>:                                Functions<5>.       (line  642)
* TZ <2>:                                Functions<5>.       (line  650)
* TZ <3>:                                Functions<5>.       (line  655)
* TZ <4>:                                Functions<5>.       (line  657)
* TZ <5>:                                Functions<5>.       (line  718)
* tzinfo (class in datetime):            tzinfo Objects.     (line    6)
* tzinfo (datetime.datetime attribute):  datetime Objects.   (line  333)
* tzinfo (datetime.time attribute):      time Objects.       (line   66)
* tzname (in module time):               Timezone Constants. (line   23)
* tzname() (datetime.datetime method):   datetime Objects.   (line  546)
* tzname() (datetime.time method):       time Objects.       (line  255)
* tzname() (datetime.timezone method):   timezone Objects.   (line   42)
* tzname() (datetime.tzinfo method):     tzinfo Objects.     (line  124)
* TZPATH (in module zoneinfo):           Globals.            (line    6)
* tzset() (in module time):              Functions<5>.       (line  638)
* U (in module re):                      Flags.              (line  117)
* u'; string literal:                    Literals.           (line    8)
* u"; string literal:                    Literals.           (line    8)
* UAdd (class in ast):                   Expressions<2>.     (line   27)
* ucd_3_2_0 (in module unicodedata):     unicodedata — Unicode Database.
                                                             (line  183)
* udata (select.kevent attribute):       Kevent Objects.     (line  179)
* UDPServer (class in socketserver):     socketserver — A framework for network servers.
                                                             (line   30)
* UF_APPEND (in module stat):            stat — Interpreting stat results.
                                                             (line  352)
* UF_COMPRESSED (in module stat):        stat — Interpreting stat results.
                                                             (line  364)
* UF_DATAVAULT (in module stat):         stat — Interpreting stat results.
                                                             (line  374)
* UF_HIDDEN (in module stat):            stat — Interpreting stat results.
                                                             (line  380)
* UF_IMMUTABLE (in module stat):         stat — Interpreting stat results.
                                                             (line  348)
* UF_NODUMP (in module stat):            stat — Interpreting stat results.
                                                             (line  344)
* UF_NOUNLINK (in module stat):          stat — Interpreting stat results.
                                                             (line  360)
* UF_OPAQUE (in module stat):            stat — Interpreting stat results.
                                                             (line  356)
* UF_SETTABLE (in module stat):          stat — Interpreting stat results.
                                                             (line  338)
* UF_TRACKED (in module stat):           stat — Interpreting stat results.
                                                             (line  368)
* UID (class in plistlib):               plistlib — Generate and parse Apple plist files.
                                                             (line  141)
* uid (tarfile.TarInfo attribute):       TarInfo Objects.    (line  105)
* uid() (imaplib.IMAP4 method):          IMAP4 Objects.      (line  367)
* uidl() (poplib.POP3 method):           POP3 Objects.       (line   99)
* ULONG_MAX (C macro):                   Integer Objects.    (line  261)
* ulp() (in module math):                Floating point manipulation functions.
                                                             (line  108)
* umask() (in module os):                Process Parameters. (line  535)
* unalias (pdb command):                 Debugger commands.  (line  396)
* uname (tarfile.TarInfo attribute):     TarInfo Objects.    (line  121)
* uname() (in module os):                Process Parameters. (line  542)
* uname() (in module platform):          Cross platform.     (line  146)
* UNARY_INVERT (opcode):                 Python Bytecode Instructions.
                                                             (line  210)
* UNARY_NEGATIVE (opcode):               Python Bytecode Instructions.
                                                             (line  199)
* UNARY_NOT (opcode):                    Python Bytecode Instructions.
                                                             (line  203)
* unary; arithmetic; operation:          Unary arithmetic and bitwise operations.
                                                             (line    6)
* unary; bitwise; operation:             Unary arithmetic and bitwise operations.
                                                             (line    6)
* unaryfunc (C type):                    Slot Type typedefs. (line  108)
* UnaryOp (class in ast):                Expressions<2>.     (line   22)
* unbinding; name:                       The del statement<2>.
                                                             (line   15)
* UnboundLocalError:                     Resolution of names.
                                                             (line   16)
* UnboundLocalError <1>:                 Concrete exceptions.
                                                             (line  428)
* unbuffered I/O:                        Built-in Functions. (line 1464)
* UNC paths; and os.makedirs():          Files and Directories.
                                                             (line  544)
* uncancel() (asyncio.Task method):      Task object.        (line  270)
* UNCHECKED_HASH (py_compile.PycInvalidationMode attribute): py_compile — Compile Python source files.
                                                             (line  115)
* unconsumed_tail (zlib.Decompress attribute): zlib — Compression compatible with gzip.
                                                             (line  243)
* unctrl() (in module curses.ascii):     curses ascii — Utilities for ASCII characters.
                                                             (line  228)
* unctrl() (in module curses):           Functions<6>.       (line  554)
* Underflow (class in decimal):          Signals.            (line   95)
* undisplay (pdb command):               Debugger commands.  (line  344)
* undo() (in module turtle):             Turtle motion.      (line  325)
* undobufferentries() (in module turtle): Special Turtle methods.
                                                             (line   74)
* undoc_header (cmd.Cmd attribute):      Cmd Objects.        (line  165)
* unescape() (in module html):           html — HyperText Markup Language support.
                                                             (line   24)
* unescape() (in module xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   28)
* UnexpectedException:                   Debugging.          (line  208)
* unexpectedSuccesses (unittest.TestResult attribute): Loading and running tests.
                                                             (line  269)
* unfreeze() (in module gc):             gc — Garbage Collector interface.
                                                             (line  222)
* unget_wch() (in module curses):        Functions<6>.       (line  574)
* ungetch() (in module curses):          Functions<6>.       (line  561)
* ungetch() (in module msvcrt):          Console I/O.        (line   45)
* ungetmouse() (in module curses):       Functions<6>.       (line  583)
* ungetwch() (in module msvcrt):         Console I/O.        (line   51)
* unhexlify() (in module binascii):      binascii — Convert between binary and ASCII.
                                                             (line  144)
* Unicode:                               Immutable sequences.
                                                             (line   15)
* Unicode <1>:                           unicodedata — Unicode Database.
                                                             (line    6)
* Unicode <2>:                           codecs — Codec registry and base classes.
                                                             (line    8)
* UNICODE (in module re):                Flags.              (line  117)
* Unicode Consortium:                    String and Bytes literals.
                                                             (line   36)
* unicode_literals (in module __future__): Module Contents<4>.
                                                             (line   39)
* Unicode; database:                     unicodedata — Unicode Database.
                                                             (line    6)
* UnicodeDecodeError:                    Concrete exceptions.
                                                             (line  468)
* UnicodeEncodeError:                    Concrete exceptions.
                                                             (line  463)
* UnicodeError:                          Concrete exceptions.
                                                             (line  434)
* UnicodeTranslateError:                 Concrete exceptions.
                                                             (line  473)
* UnicodeWarning:                        Warnings.           (line   68)
* unidata_version (in module unicodedata): unicodedata — Unicode Database.
                                                             (line  179)
* unified_diff() (in module difflib):    difflib — Helpers for computing deltas.
                                                             (line  292)
* uniform() (in module random):          Real-valued distributions.
                                                             (line   16)
* UnimplementedFileMode:                 http client — HTTP protocol client.
                                                             (line  153)
* Union (class in ctypes):               Structured data types.
                                                             (line    6)
* Union (in module typing):              Special forms.      (line    9)
* union; type:                           Union Type.         (line    6)
* union() (frozenset method):            Set Types — set frozenset.
                                                             (line   98)
* union() (set method):                  Set Types — set frozenset.
                                                             (line   98)
* UnionType (class in types):            Standard Interpreter Types.
                                                             (line  180)
* UNIQUE (enum.EnumCheck attribute):     Data types.         (line  657)
* unique() (in module enum):             Utilities and decorators.
                                                             (line   53)
* unittest command line option; -b:      Command-line options<4>.
                                                             (line    8)
* unittest command line option; -buffer: Command-line options<4>.
                                                             (line    8)
* unittest command line option; -c:      Command-line options<4>.
                                                             (line   15)
* unittest command line option; -catch:  Command-line options<4>.
                                                             (line   15)
* unittest command line option; -durations: Command-line options<4>.
                                                             (line   49)
* unittest command line option; -f:      Command-line options<4>.
                                                             (line   24)
* unittest command line option; -failfast: Command-line options<4>.
                                                             (line   24)
* unittest command line option; -k:      Command-line options<4>.
                                                             (line   28)
* unittest command line option; -locals: Command-line options<4>.
                                                             (line   45)
* unittest-discover command line option; -p: Test Discovery. (line   35)
* unittest-discover command line option; -pattern: Test Discovery.
                                                             (line   35)
* unittest-discover command line option; -s: Test Discovery. (line   31)
* unittest-discover command line option; -start-directory: Test Discovery.
                                                             (line   31)
* unittest-discover command line option; -t: Test Discovery. (line   39)
* unittest-discover command line option; -top-level-directory: Test Discovery.
                                                             (line   39)
* unittest-discover command line option; -v: Test Discovery. (line   27)
* unittest-discover command line option; -verbose: Test Discovery.
                                                             (line   27)
* universal newlines:                    Glossary.           (line 1736)
* universal newlines; bytearray.splitlines method: Bytes and Bytearray Operations.
                                                             (line  638)
* universal newlines; bytes.splitlines method: Bytes and Bytearray Operations.
                                                             (line  638)
* universal newlines; csv.reader function: Module Contents<2>.
                                                             (line    8)
* universal newlines; importlib.abc.InspectLoader.get_source method: importlib abc – Abstract base classes related to import.
                                                             (line  215)
* universal newlines; io.IncrementalNewlineDecoder class: Text I/O<2>.
                                                             (line  286)
* universal newlines; io.TextIOWrapper class: Text I/O<2>.   (line  126)
* universal newlines; open() built-in function: Built-in Functions.
                                                             (line 1402)
* universal newlines; str.splitlines method: String Methods<2>.
                                                             (line  757)
* universal newlines; subprocess module: Frequently Used Arguments.
                                                             (line   33)
* universal newlines; What's new:        PEP 3116 New I/O Library.
                                                             (line   45)
* universal newlines; What's new <1>:    New Improved and Removed Modules.
                                                             (line  137)
* universal newlines; What's new <2>:    PEP 324 New subprocess Module.
                                                             (line   36)
* universal newlines; What's new <3>:    PEP 277 Unicode file name support for Windows NT.
                                                             (line   36)
* UNIX:                                  Complete Python programs.
                                                             (line   25)
* unix_dialect (class in csv):           Module Contents<2>. (line  219)
* unix_shell (in module test.support):   test support — Utilities for the Python test suite.
                                                             (line   44)
* UNIX; file control:                    fcntl — The fcntl and ioctl system calls.
                                                             (line    6)
* UNIX; I/O control:                     fcntl — The fcntl and ioctl system calls.
                                                             (line    6)
* UnixDatagramServer (class in socketserver): socketserver — A framework for network servers.
                                                             (line   37)
* UnixStreamServer (class in socketserver): socketserver — A framework for network servers.
                                                             (line   37)
* unknown (uuid.SafeUUID attribute):     uuid — UUID objects according to RFC 4122.
                                                             (line   42)
* unknown_decl() (html.parser.HTMLParser method): HTMLParser Methods.
                                                             (line  135)
* unknown_open() (urllib.request.BaseHandler method): BaseHandler Objects.
                                                             (line   55)
* unknown_open() (urllib.request.UnknownHandler method): UnknownHandler Objects.
                                                             (line    6)
* UnknownHandler (class in urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  441)
* UnknownProtocol:                       http client — HTTP protocol client.
                                                             (line  145)
* UnknownTransferEncoding:               http client — HTTP protocol client.
                                                             (line  149)
* unlink() (in module os):               Files and Directories.
                                                             (line 1581)
* unlink() (in module test.support.os_helper): test support os_helper — Utilities for os tests.
                                                             (line  163)
* unlink() (multiprocessing.shared_memory.SharedMemory method): multiprocessing shared_memory — Shared memory for direct access across processes.
                                                             (line  103)
* unlink() (pathlib.Path method):        Renaming and deleting.
                                                             (line   48)
* unlink() (xml.dom.minidom.Node method): DOM Objects.       (line   10)
* unload() (in module test.support.import_helper): test support import_helper — Utilities for import tests.
                                                             (line   76)
* unlock() (mailbox.Babyl method):       Babyl objects.      (line   59)
* unlock() (mailbox.Mailbox method):     Mailbox objects.    (line  264)
* unlock() (mailbox.Maildir method):     Maildir objects.    (line  209)
* unlock() (mailbox.mbox method):        mbox objects.       (line   57)
* unlock() (mailbox.MH method):          MH objects.         (line   87)
* unlock() (mailbox.MMDF method):        MMDF objects.       (line   47)
* unlockpt() (in module os):             File Descriptor Operations.
                                                             (line  907)
* UNNAMED_SECTION (in module configparser): ConfigParser Objects.
                                                             (line  339)
* Unpack (in module typing):             Special forms.      (line  583)
* unpack_archive() (in module shutil):   Archiving operations.
                                                             (line  124)
* UNPACK_EX (opcode):                    Python Bytecode Instructions.
                                                             (line  583)
* unpack_from() (in module struct):      Functions and Exceptions.
                                                             (line   34)
* unpack_from() (struct.Struct method):  Classes<3>.         (line   40)
* UNPACK_SEQUENCE (opcode):              Python Bytecode Instructions.
                                                             (line  574)
* unpack() (in module struct):           Functions and Exceptions.
                                                             (line   26)
* unpack() (struct.Struct method):       Classes<3>.         (line   34)
* unpacking; dictionary:                 Dictionary displays.
                                                             (line   23)
* unpacking; in function calls:          Calls.              (line   73)
* unparse() (in module ast):             ast Helpers.        (line   68)
* unparsedEntityDecl() (xml.sax.handler.DTDHandler method): DTDHandler Objects.
                                                             (line   12)
* UnparsedEntityDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  339)
* Unpickler (class in pickle):           Module Interface.   (line  227)
* UnpicklingError:                       Module Interface.   (line  108)
* unquote_plus() (in module urllib.parse): URL Quoting.      (line   81)
* unquote_to_bytes() (in module urllib.parse): URL Quoting.  (line   91)
* unquote() (in module email.utils):     email utils Miscellaneous utilities.
                                                             (line   50)
* unquote() (in module urllib.parse):    URL Quoting.        (line   61)
* unraisablehook() (in module sys):      sys — System-specific parameters and functions.
                                                             (line 1960)
* unreachable object:                    Objects values and types.
                                                             (line   36)
* unrecognized escape sequence:          Escape sequences.   (line  107)
* unregister_archive_format() (in module shutil): Archiving operations.
                                                             (line  119)
* unregister_dialect() (in module csv):  Module Contents<2>. (line   80)
* unregister_unpack_format() (in module shutil): Archiving operations.
                                                             (line  185)
* unregister() (in module atexit):       atexit — Exit handlers.
                                                             (line   57)
* unregister() (in module codecs):       codecs — Codec registry and base classes.
                                                             (line  170)
* unregister() (in module faulthandler): Dumping the traceback on a user signal.
                                                             (line   23)
* unregister() (select.devpoll method):  /dev/poll Polling Objects.
                                                             (line   55)
* unregister() (select.epoll method):    Edge and Level Trigger Polling epoll Objects.
                                                             (line   89)
* unregister() (select.poll method):     Polling Objects.    (line   67)
* unregister() (selectors.BaseSelector method): Classes<4>.  (line   80)
* unsafe (uuid.SafeUUID attribute):      uuid — UUID objects according to RFC 4122.
                                                             (line   38)
* unselect() (imaplib.IMAP4 method):     IMAP4 Objects.      (line  378)
* unset() (test.support.os_helper.EnvironmentVarGuard method): test support os_helper — Utilities for os tests.
                                                             (line   70)
* unsetenv() (in module os):             Process Parameters. (line  577)
* unshare() (in module os):              Process Parameters. (line  595)
* UnstructuredHeader (class in email.headerregistry): email headerregistry Custom Header Objects.
                                                             (line  115)
* unsubscribe() (imaplib.IMAP4 method):  IMAP4 Objects.      (line  374)
* UnsupportedOperation:                  Exceptions<6>.      (line    6)
* UnsupportedOperation <1>:              High-level Module Interface.
                                                             (line   72)
* until (pdb command):                   Debugger commands.  (line  210)
* untokenize() (in module tokenize):     Tokenizing Input.   (line   54)
* untouchwin() (curses.window method):   Window Objects.     (line  584)
* unused_data (bz2.BZ2Decompressor attribute): Incremental de compression.
                                                             (line   78)
* unused_data (lzma.LZMADecompressor attribute): Compressing and decompressing data in memory.
                                                             (line  167)
* unused_data (zlib.Decompress attribute): zlib — Compression compatible with gzip.
                                                             (line  235)
* unverifiable (urllib.request.Request attribute): Request Objects.
                                                             (line   47)
* unwrap() (in module inspect):          Classes and functions<2>.
                                                             (line  139)
* unwrap() (in module urllib.parse):     URL Parsing.        (line  347)
* unwrap() (ssl.SSLSocket method):       SSL sockets.        (line  296)
* up (pdb command):                      Debugger commands.  (line   92)
* up() (in module turtle):               Drawing state.      (line   12)
* update_abstractmethods() (in module abc): abc — Abstract Base Classes.
                                                             (line  337)
* update_authenticated() (urllib.request.HTTPPasswordMgrWithPriorAuth method): HTTPPasswordMgrWithPriorAuth Objects.
                                                             (line   24)
* update_lines_cols() (in module curses): Functions<6>.      (line  567)
* update_panels() (in module curses.panel): Functions<7>.    (line   23)
* update_visible() (mailbox.BabylMessage method): BabylMessage objects.
                                                             (line   76)
* update_wrapper() (in module functools): functools — Higher-order functions and operations on callable objects.
                                                             (line  647)
* update() (collections.Counter method): Counter objects.    (line  129)
* update() (dict method):                Mapping Types — dict.
                                                             (line  231)
* update() (hashlib.hash method):        Hash Objects.       (line   31)
* update() (hmac.HMAC method):           hmac — Keyed-Hashing for Message Authentication.
                                                             (line   51)
* update() (http.cookies.Morsel method): Morsel Objects.     (line   91)
* update() (in module turtle):           Animation control.  (line   46)
* update() (mailbox.Mailbox method):     Mailbox objects.    (line  234)
* update() (mailbox.Maildir method):     Maildir objects.    (line  193)
* update() (set method):                 Set Types — set frozenset.
                                                             (line  172)
* update() (trace.CoverageResults method): Programmatic Interface.
                                                             (line   52)
* upgrade_dependencies() (venv.EnvBuilder method): API<2>.   (line  166)
* upper() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  730)
* upper() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  730)
* upper() (str method):                  String Methods<2>.  (line  938)
* urandom() (in module os):              Random numbers<2>.  (line   29)
* URL:                                   urllib parse — Parse URLs into components.
                                                             (line    8)
* URL <1>:                               urllib robotparser — Parser for robots txt.
                                                             (line    8)
* URL <2>:                               http server — HTTP servers.
                                                             (line    8)
* url (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   51)
* url (urllib.error.HTTPError attribute): urllib error — Exception classes raised by urllib request.
                                                             (line   37)
* url (urllib.response.addinfourl attribute): urllib response — Response classes used by urllib.
                                                             (line   14)
* url (xmlrpc.client.ProtocolError attribute): ProtocolError Objects.
                                                             (line   13)
* URL; parsing:                          urllib parse — Parse URLs into components.
                                                             (line    8)
* url2pathname() (in module urllib.request): urllib request — Extensible library for opening URLs.
                                                             (line  155)
* urlcleanup() (in module urllib.request): Legacy interface. (line   62)
* urldefrag() (in module urllib.parse):  URL Parsing.        (line  321)
* urlencode() (in module urllib.parse):  URL Quoting.        (line  104)
* URLError:                              urllib error — Exception classes raised by urllib request.
                                                             (line   16)
* urljoin() (in module urllib.parse):    URL Parsing.        (line  284)
* urlopen() (in module urllib.request):  urllib request — Extensible library for opening URLs.
                                                             (line   33)
* URLopener (class in urllib.request):   Legacy interface.   (line   67)
* urlparse() (in module urllib.parse):   URL Parsing.        (line  258)
* urlretrieve() (in module urllib.request): Legacy interface.
                                                             (line   10)
* urlsafe_b64decode() (in module base64): RFC 4648 Encodings.
                                                             (line   66)
* urlsafe_b64encode() (in module base64): RFC 4648 Encodings.
                                                             (line   59)
* urlsplit() (in module urllib.parse):   URL Parsing.        (line    9)
* urlunparse() (in module urllib.parse): URL Parsing.        (line  275)
* urlunsplit() (in module urllib.parse): URL Parsing.        (line  250)
* urn (uuid.UUID attribute):             uuid — UUID objects according to RFC 4122.
                                                             (line  136)
* US (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line  117)
* use_default_colors() (in module curses): Functions<6>.     (line  598)
* use_env() (in module curses):          Functions<6>.       (line  588)
* use_rawinput (cmd.Cmd attribute):      Cmd Objects.        (line  176)
* USE_STACKCHECK (C macro):              Operating System Utilities.
                                                             (line   91)
* use_tool_id() (in module sys.monitoring): Registering and using tools.
                                                             (line    6)
* UseForeignDTD() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line   62)
* USER:                                  getpass — Portable password input.
                                                             (line   43)
* USER_BASE (in module site):            Module contents<6>. (line   31)
* user_call() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  264)
* user_exception() (bdb.Bdb method):     bdb — Debugger framework.
                                                             (line  283)
* user_line() (bdb.Bdb method):          bdb — Debugger framework.
                                                             (line  272)
* user_return() (bdb.Bdb method):        bdb — Debugger framework.
                                                             (line  278)
* USER_SITE (in module site):            Module contents<6>. (line   19)
* user-defined; function:                User-defined functions.
                                                             (line    6)
* user-defined; function; call:          Calls.              (line  132)
* user-defined; method:                  Instance methods.   (line    6)
* user; effective id:                    Process Parameters. (line  182)
* user; id:                              Process Parameters. (line  329)
* user; id, setting:                     Process Parameters. (line  518)
* user() (poplib.POP3 method):           POP3 Objects.       (line   31)
* usercustomize:                         The Customization Modules.
                                                             (line    6)
* usercustomize <1>:                     The Customization Modules.
                                                             (line   21)
* UserDict (class in collections):       UserDict objects.   (line   12)
* UserList (class in collections):       UserList objects.   (line   16)
* USERNAME:                              os path — Common pathname manipulations.
                                                             (line  152)
* USERNAME <1>:                          Process Parameters. (line  234)
* USERNAME <2>:                          getpass — Portable password input.
                                                             (line   44)
* username (email.headerregistry.Address attribute): email headerregistry Custom Header Objects.
                                                             (line  431)
* USERPROFILE:                           os path<5>.         (line   14)
* USERPROFILE <1>:                       Changes in the Python API<5>.
                                                             (line  117)
* USERPROFILE <2>:                       Windows<46>.        (line   15)
* USERPROFILE <3>:                       os path — Common pathname manipulations.
                                                             (line  149)
* userptr() (curses.panel.Panel method): Panel Objects.      (line   57)
* UserString (class in collections):     UserString objects. (line   12)
* UserWarning:                           Warnings.           (line   13)
* USTAR_FORMAT (in module tarfile):      tarfile — Read and write tar archive files.
                                                             (line  326)
* USub (class in ast):                   Expressions<2>.     (line   27)
* UTC:                                   time — Time access and conversions.
                                                             (line   39)
* utc (datetime.timezone attribute):     timezone Objects.   (line   68)
* UTC (in module datetime):              Constants.          (line   18)
* utcfromtimestamp() (datetime.datetime class method): datetime Objects.
                                                             (line  131)
* utcnow() (datetime.datetime class method): datetime Objects.
                                                             (line   81)
* utcoffset() (datetime.datetime method): datetime Objects.  (line  526)
* utcoffset() (datetime.time method):    time Objects.       (line  235)
* utcoffset() (datetime.timezone method): timezone Objects.  (line   30)
* utcoffset() (datetime.tzinfo method):  tzinfo Objects.     (line   36)
* utctimetuple() (datetime.datetime method): datetime Objects.
                                                             (line  571)
* utf8 (email.policy.EmailPolicy attribute): email policy Policy Objects.
                                                             (line  379)
* utf8_enabled (imaplib.IMAP4 attribute): IMAP4 Objects.     (line  406)
* utf8_mode (sys.flags attribute):       sys — System-specific parameters and functions.
                                                             (line  570)
* utf8() (poplib.POP3 method):           POP3 Objects.       (line  106)
* utime() (in module os):                Files and Directories.
                                                             (line 1595)
* UUID (class in uuid):                  uuid — UUID objects according to RFC 4122.
                                                             (line   47)
* uuid command line option; -h:          Command-Line Usage<2>.
                                                             (line   14)
* uuid command line option; -help:       Command-Line Usage<2>.
                                                             (line   14)
* uuid command line option; -n:          Command-Line Usage<2>.
                                                             (line   24)
* uuid command line option; -N:          Command-Line Usage<2>.
                                                             (line   32)
* uuid command line option; -name:       Command-Line Usage<2>.
                                                             (line   32)
* uuid command line option; -namespace:  Command-Line Usage<2>.
                                                             (line   24)
* uuid command line option; -u:          Command-Line Usage<2>.
                                                             (line   18)
* uuid command line option; -uuid:       Command-Line Usage<2>.
                                                             (line   18)
* uuid1() (in module uuid):              uuid — UUID objects according to RFC 4122.
                                                             (line  179)
* uuid3() (in module uuid):              uuid — UUID objects according to RFC 4122.
                                                             (line  187)
* uuid4() (in module uuid):              uuid — UUID objects according to RFC 4122.
                                                             (line  193)
* uuid5() (in module uuid):              uuid — UUID objects according to RFC 4122.
                                                             (line  197)
* v4_int_to_packed() (in module ipaddress): Other Module Level Functions.
                                                             (line    8)
* v6_int_to_packed() (in module ipaddress): Other Module Level Functions.
                                                             (line   20)
* valid_signals() (in module signal):    Module contents<3>. (line  334)
* validator() (in module wsgiref.validate): wsgiref validate — WSGI conformance checker.
                                                             (line   22)
* value:                                 Dictionary displays.
                                                             (line    6)
* value (ctypes._SimpleCData attribute): Fundamental data types<2>.
                                                             (line   17)
* value (enum.Enum attribute):           Data types.         (line  131)
* value (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   31)
* value (http.cookies.Morsel attribute): Morsel Objects.     (line   49)
* value (StopIteration attribute):       Concrete exceptions.
                                                             (line  272)
* value (xml.dom.Attr attribute):        Attr Objects.       (line   23)
* value of an object:                    Objects values and types.
                                                             (line   10)
* value_decode() (http.cookies.BaseCookie method): Cookie Objects.
                                                             (line    6)
* value_encode() (http.cookies.BaseCookie method): Cookie Objects.
                                                             (line   13)
* Value() (in module multiprocessing.sharedctypes): The multiprocessing sharedctypes module.
                                                             (line   71)
* Value() (in module multiprocessing):   Shared ctypes Objects.
                                                             (line    9)
* Value() (multiprocessing.managers.SyncManager method): Managers.
                                                             (line  217)
* ValueError:                            Concrete exceptions.
                                                             (line  478)
* valuerefs() (weakref.WeakValueDictionary method): weakref — Weak references.
                                                             (line  225)
* Values (class in optparse):            Defining options.   (line   84)
* values() (contextvars.Context method): Manual Context Management.
                                                             (line  137)
* values() (dict method):                Mapping Types — dict.
                                                             (line  248)
* values() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  236)
* values() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  345)
* values() (mailbox.Mailbox method):     Mailbox objects.    (line  127)
* values() (types.MappingProxyType method): Standard Interpreter Types.
                                                             (line  276)
* ValuesView (class in collections.abc): Collections Abstract Base Classes – Detailed Descriptions.
                                                             (line  124)
* ValuesView (class in typing):          Aliases to container ABCs in collections abc.
                                                             (line  120)
* var (contextvars.Token attribute):     Context Variables.  (line   85)
* variable annotation:                   Glossary.           (line 1744)
* variance (statistics.NormalDist attribute): NormalDist objects.
                                                             (line   40)
* variance() (in module statistics):     Function details.   (line  444)
* variant (uuid.UUID attribute):         uuid — UUID objects according to RFC 4122.
                                                             (line  140)
* VBAR (in module token):                token — Constants used with Python parse trees.
                                                             (line  209)
* vbar (tkinter.scrolledtext.ScrolledText attribute): tkinter scrolledtext — Scrolled Text Widget.
                                                             (line   30)
* VBAREQUAL (in module token):           token — Constants used with Python parse trees.
                                                             (line  281)
* VC_ASSEMBLY_PUBLICKEYTOKEN (in module msvcrt): Other Functions.
                                                             (line   93)
* Vec2D (class in turtle):               Public classes.     (line   86)
* vectorcallfunc (C type):               The Vectorcall Protocol.
                                                             (line   41)
* venv command line option; -clear:      Creating virtual environments.
                                                             (line   64)
* venv command line option; -copies:     Creating virtual environments.
                                                             (line   59)
* venv command line option; -prompt:     Creating virtual environments.
                                                             (line   79)
* venv command line option; -symlinks:   Creating virtual environments.
                                                             (line   54)
* venv command line option; -system-site-packages: Creating virtual environments.
                                                             (line   49)
* venv command line option; -upgrade:    Creating virtual environments.
                                                             (line   69)
* venv command line option; -upgrade-deps: Creating virtual environments.
                                                             (line   83)
* venv command line option; -without-pip: Creating virtual environments.
                                                             (line   74)
* venv command line option; -without-scm-ignore-files: Creating virtual environments.
                                                             (line   87)
* venv command line option; ENV_DIR:     Creating virtual environments.
                                                             (line   44)
* VERBOSE (in module re):                Flags.              (line  127)
* verbose (in module tabnanny):          tabnanny — Detection of ambiguous indentation.
                                                             (line   26)
* verbose (in module test.support):      test support — Utilities for the Python test suite.
                                                             (line   30)
* verbose (sys.flags attribute):         sys — System-specific parameters and functions.
                                                             (line  554)
* VERIFY_ALLOW_PROXY_CERTS (in module ssl): Constants<9>.    (line   98)
* verify_client_post_handshake() (ssl.SSLSocket method): SSL sockets.
                                                             (line  305)
* verify_code (ssl.SSLCertVerificationError attribute): Exceptions<16>.
                                                             (line   86)
* VERIFY_CRL_CHECK_CHAIN (in module ssl): Constants<9>.      (line   84)
* VERIFY_CRL_CHECK_LEAF (in module ssl): Constants<9>.       (line   73)
* VERIFY_DEFAULT (in module ssl):        Constants<9>.       (line   65)
* verify_flags (ssl.SSLContext attribute): SSL contexts.     (line  631)
* verify_generated_headers (email.policy.Policy attribute): email policy Policy Objects.
                                                             (line  204)
* verify_message (ssl.SSLCertVerificationError attribute): Exceptions<16>.
                                                             (line   90)
* verify_mode (ssl.SSLContext attribute): SSL contexts.      (line  646)
* verify_request() (socketserver.BaseServer method): Server Objects.
                                                             (line  178)
* VERIFY_X509_PARTIAL_CHAIN (in module ssl): Constants<9>.   (line  114)
* VERIFY_X509_STRICT (in module ssl):    Constants<9>.       (line   91)
* VERIFY_X509_TRUSTED_FIRST (in module ssl): Constants<9>.   (line  105)
* verify() (in module enum):             Utilities and decorators.
                                                             (line   72)
* verify() (smtplib.SMTP method):        SMTP Objects.       (line   91)
* VerifyFlags (class in ssl):            Constants<9>.       (line  125)
* VerifyMode (class in ssl):             Constants<9>.       (line   59)
* version (email.headerregistry.MIMEVersionHeader attribute): email headerregistry Custom Header Objects.
                                                             (line  241)
* version (http.client.HTTPResponse attribute): HTTPResponse Objects.
                                                             (line   46)
* version (http.cookiejar.Cookie attribute): Cookie Objects<2>.
                                                             (line   19)
* version (http.cookies.Morsel attribute): Morsel Objects.   (line   13)
* version (in module curses):            Constants<6>.       (line   18)
* version (in module marshal):           marshal — Internal Python object serialization.
                                                             (line  129)
* version (in module sqlite3):           Module constants.   (line  127)
* version (in module sys):               sys — System-specific parameters and functions.
                                                             (line 2008)
* version (in module sys) <1>:           Process-wide parameters.
                                                             (line  164)
* version (in module sys) <2>:           Process-wide parameters.
                                                             (line  201)
* version (in module sys) <3>:           Process-wide parameters.
                                                             (line  212)
* version (ipaddress.IPv4Address attribute): Address objects.
                                                             (line   45)
* version (ipaddress.IPv4Network attribute): Network objects.
                                                             (line   63)
* version (ipaddress.IPv6Address attribute): Address objects.
                                                             (line  271)
* version (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  293)
* version (sys.thread_info attribute):   sys — System-specific parameters and functions.
                                                             (line 1945)
* version (urllib.request.URLopener attribute): Legacy interface.
                                                             (line  138)
* version (uuid.UUID attribute):         uuid — UUID objects according to RFC 4122.
                                                             (line  147)
* version_info (in module sqlite3):      Module constants.   (line  137)
* version_info (in module sys):          sys — System-specific parameters and functions.
                                                             (line 2023)
* version_string() (http.server.BaseHTTPRequestHandler method): http server — HTTP servers.
                                                             (line  316)
* version() (in module ensurepip):       Module API.         (line    8)
* version() (in module importlib.metadata): Distribution versions.
                                                             (line    6)
* version() (in module platform):        Cross platform.     (line  138)
* version() (ssl.SSLSocket method):      SSL sockets.        (line  327)
* vformat() (string.Formatter method):   Custom string formatting.
                                                             (line   26)
* virtual environment:                   Glossary.           (line 1767)
* virtual machine:                       Glossary.           (line 1776)
* visit_Constant() (ast.NodeVisitor method): ast Helpers.    (line  210)
* visit() (ast.NodeVisitor method):      ast Helpers.        (line  194)
* visitproc (C type):                    Supporting Cyclic Garbage Collection.
                                                             (line  153)
* vline() (curses.window method):        Window Objects.     (line  589)
* voidcmd() (ftplib.FTP method):         FTP objects.        (line  164)
* volume (zipfile.ZipInfo attribute):    ZipInfo objects.    (line  134)
* vonmisesvariate() (in module random):  Real-valued distributions.
                                                             (line   93)
* VT (in module curses.ascii):           curses ascii — Utilities for ASCII characters.
                                                             (line   57)
* W_OK (in module os):                   Files and Directories.
                                                             (line  107)
* wait_closed() (asyncio.Server method): Server objects.     (line  123)
* wait_closed() (asyncio.StreamWriter method): StreamWriter. (line  117)
* wait_for() (asyncio.Condition method): Condition.          (line  102)
* wait_for() (in module asyncio):        Timeouts.           (line  122)
* wait_for() (threading.Condition method): Condition objects.
                                                             (line  128)
* wait_process() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  423)
* wait_threads_exit() (in module test.support.threading_helper): test support threading_helper — Utilities for threading tests.
                                                             (line   41)
* wait_until_any_call_with() (unittest.mock.ThreadingMock method): The Mock Class.
                                                             (line  981)
* wait_until_called() (unittest.mock.ThreadingMock method): The Mock Class.
                                                             (line  966)
* wait() (asyncio.Barrier method):       Barrier.            (line   51)
* wait() (asyncio.Condition method):     Condition.          (line   85)
* wait() (asyncio.Event method):         Event.              (line   44)
* wait() (asyncio.subprocess.Process method): Interacting with Subprocesses.
                                                             (line   38)
* wait() (in module asyncio):            Waiting primitives. (line    6)
* wait() (in module concurrent.futures): Module Functions.   (line    6)
* wait() (in module multiprocessing.connection): Listeners and Clients.
                                                             (line  113)
* wait() (in module os):                 Process Management. (line  818)
* wait() (multiprocessing.pool.AsyncResult method): Process Pools.
                                                             (line  210)
* wait() (subprocess.Popen method):      Popen Objects.      (line   13)
* wait() (threading.Barrier method):     Barrier objects.    (line   42)
* wait() (threading.Condition method):   Condition objects.  (line   97)
* wait() (threading.Event method):       Event objects.      (line   42)
* wait3() (in module os):                Process Management. (line  928)
* wait4() (in module os):                Process Management. (line  942)
* waitid() (in module os):               Process Management. (line  842)
* waitpid() (in module os):              Process Management. (line  881)
* waitstatus_to_exitcode() (in module os): Process Management.
                                                             (line 1060)
* walk_packages() (in module pkgutil):   pkgutil — Package extension utility.
                                                             (line  145)
* walk_stack() (in module traceback):    Module-Level Functions<2>.
                                                             (line  185)
* walk_tb() (in module traceback):       Module-Level Functions<2>.
                                                             (line  194)
* walk() (email.message.EmailMessage method): email message Representing an email message.
                                                             (line  467)
* walk() (email.message.Message method): email message Message Representing an email message using the compat32 API.
                                                             (line  637)
* walk() (in module ast):                ast Helpers.        (line  177)
* walk() (in module os):                 Files and Directories.
                                                             (line 1637)
* walk() (pathlib.Path method):          Reading directories.
                                                             (line  108)
* walrus operator:                       Boolean operations. (line   38)
* walrus operator <1>:                   Glossary.           (line 1782)
* want (doctest.Example attribute):      Example Objects.    (line   22)
* warn_default_encoding (sys.flags attribute): sys — System-specific parameters and functions.
                                                             (line  580)
* warn_explicit() (in module warnings):  Available Functions.
                                                             (line   62)
* warn() (in module warnings):           Available Functions.
                                                             (line    6)
* Warning:                               Warnings.           (line    9)
* Warning <1>:                           Exceptions<7>.      (line    8)
* WARNING (in module logging):           Logging Levels.     (line   33)
* WARNING (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  198)
* warning() (in module logging):         Module-Level Functions.
                                                             (line   70)
* warning() (logging.Logger method):     Logger Objects.     (line  293)
* warning() (xml.sax.handler.ErrorHandler method): ErrorHandler Objects.
                                                             (line   29)
* warnings:                              warnings — Warning control.
                                                             (line    8)
* WarningsRecorder (class in test.support.warnings_helper): test support warnings_helper — Utilities for warnings tests.
                                                             (line  116)
* warnoptions (in module sys):           sys — System-specific parameters and functions.
                                                             (line 2036)
* wasSuccessful() (unittest.TestResult method): Loading and running tests.
                                                             (line  315)
* WatchedFileHandler (class in logging.handlers): WatchedFileHandler.
                                                             (line   24)
* Wave_read (class in wave):             Wave_read Objects.  (line    6)
* Wave_write (class in wave):            Wave_write Objects. (line    6)
* WCONTINUED (in module os):             Process Management. (line  982)
* WCOREDUMP() (in module os):            Process Management. (line 1100)
* WeakKeyDictionary (class in weakref):  weakref — Weak references.
                                                             (line  164)
* WeakMethod (class in weakref):         weakref — Weak references.
                                                             (line  234)
* WeakSet (class in weakref):            weakref — Weak references.
                                                             (line  229)
* WeakValueDictionary (class in weakref): weakref — Weak references.
                                                             (line  212)
* webbrowser command line option; -n:    Command-line interface<4>.
                                                             (line   10)
* webbrowser command line option; -new-tab: Command-line interface<4>.
                                                             (line   14)
* webbrowser command line option; -new-window: Command-line interface<4>.
                                                             (line   10)
* webbrowser command line option; -t:    Command-line interface<4>.
                                                             (line   14)
* WEDNESDAY (in module calendar):        calendar — General calendar-related functions.
                                                             (line  445)
* weekday (calendar.IllegalWeekdayError attribute): calendar — General calendar-related functions.
                                                             (line  530)
* weekday() (datetime.date method):      date Objects.       (line  231)
* weekday() (datetime.datetime method):  datetime Objects.   (line  635)
* weekday() (in module calendar):        calendar — General calendar-related functions.
                                                             (line  375)
* weekheader() (in module calendar):     calendar — General calendar-related functions.
                                                             (line  380)
* weibullvariate() (in module random):   Real-valued distributions.
                                                             (line  105)
* WEXITED (in module os):                Process Management. (line  991)
* WEXITSTATUS() (in module os):          Process Management. (line 1146)
* wfile (http.server.BaseHTTPRequestHandler attribute): http server — HTTP servers.
                                                             (line  122)
* wfile (socketserver.DatagramRequestHandler attribute): Request Handler Objects.
                                                             (line   68)
* whatis (pdb command):                  Debugger commands.  (line  280)
* when() (asyncio.Timeout method):       Timeouts.           (line   67)
* when() (asyncio.TimerHandle method):   Callback handles.   (line   36)
* where (pdb command):                   Debugger commands.  (line   81)
* which() (in module shutil):            Directory and files operations.
                                                             (line  421)
* whichdb() (in module dbm):             dbm — Interfaces to Unix “databases”.
                                                             (line   29)
* While (class in ast):                  Control flow.       (line   77)
* whitespace (in module string):         String constants.   (line   52)
* whitespace (shlex.shlex attribute):    shlex Objects.      (line  104)
* whitespace_split (shlex.shlex attribute): shlex Objects.   (line  128)
* Widget (class in tkinter.ttk):         ttk Widget.         (line    9)
* width (sys.hash_info attribute):       sys — System-specific parameters and functions.
                                                             (line 1033)
* width (textwrap.TextWrapper attribute): textwrap — Text wrapping and filling.
                                                             (line  159)
* width() (in module turtle):            Drawing state.      (line   18)
* WIFCONTINUED() (in module os):         Process Management. (line 1110)
* WIFEXITED() (in module os):            Process Management. (line 1138)
* WIFSIGNALED() (in module os):          Process Management. (line 1131)
* WIFSTOPPED() (in module os):           Process Management. (line 1120)
* win32_edition() (in module platform):  Windows platform.   (line   22)
* win32_is_iot() (in module platform):   Windows platform.   (line   31)
* win32_ver() (in module platform):      Windows platform.   (line    6)
* WinDLL (class in ctypes):              Loading shared libraries.
                                                             (line   53)
* window (class in curses):              Window Objects.     (line    6)
* window manager (widgets):              The Window Manager. (line    6)
* window_height() (in module turtle):    Settings and special methods.
                                                             (line  104)
* window_width() (in module turtle):     Settings and special methods.
                                                             (line  111)
* window() (curses.panel.Panel method):  Panel Objects.      (line   62)
* Windows:                               Complete Python programs.
                                                             (line   25)
* Windows ini file:                      configparser — Configuration file parser.
                                                             (line    8)
* WindowsError:                          Concrete exceptions.
                                                             (line  499)
* WindowsPath (class in pathlib):        Concrete paths.     (line   36)
* WindowsProactorEventLoopPolicy (class in asyncio): Policy Objects.
                                                             (line   78)
* WindowsRegistryFinder (class in importlib.machinery): importlib machinery – Importers and path hooks.
                                                             (line   92)
* WindowsSelectorEventLoopPolicy (class in asyncio): Policy Objects.
                                                             (line   71)
* winerror (OSError attribute):          Concrete exceptions.
                                                             (line  176)
* WinError() (in module ctypes):         Utility functions.  (line  237)
* WINFUNCTYPE() (in module ctypes):      Function prototypes.
                                                             (line   25)
* WinSock:                               select — Waiting for I/O completion.
                                                             (line  151)
* winver (in module sys):                sys — System-specific parameters and functions.
                                                             (line 2042)
* With (class in ast):                   Control flow.       (line  230)
* WITH_EXCEPT_START (opcode):            Python Bytecode Instructions.
                                                             (line  488)
* with_hostmask (ipaddress.IPv4Interface attribute): Interface objects.
                                                             (line   55)
* with_hostmask (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  123)
* with_hostmask (ipaddress.IPv6Interface attribute): Interface objects.
                                                             (line   82)
* with_hostmask (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  325)
* with_name() (pathlib.PurePath method): Methods and properties.
                                                             (line  354)
* with_netmask (ipaddress.IPv4Interface attribute): Interface objects.
                                                             (line   46)
* with_netmask (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  118)
* with_netmask (ipaddress.IPv6Interface attribute): Interface objects.
                                                             (line   80)
* with_netmask (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  323)
* with_prefixlen (ipaddress.IPv4Interface attribute): Interface objects.
                                                             (line   37)
* with_prefixlen (ipaddress.IPv4Network attribute): Network objects.
                                                             (line  105)
* with_prefixlen (ipaddress.IPv6Interface attribute): Interface objects.
                                                             (line   78)
* with_prefixlen (ipaddress.IPv6Network attribute): Network objects.
                                                             (line  317)
* with_pymalloc() (in module test.support): test support — Utilities for the Python test suite.
                                                             (line  259)
* with_segments() (pathlib.PurePath method): Methods and properties.
                                                             (line  410)
* with_statement (in module __future__): Module Contents<4>. (line   31)
* with_stem() (pathlib.PurePath method): Methods and properties.
                                                             (line  370)
* with_suffix() (pathlib.PurePath method): Methods and properties.
                                                             (line  393)
* with_traceback() (BaseException method): Base classes.     (line   25)
* withitem (class in ast):               Control flow.       (line  241)
* WNOHANG (in module os):                Process Management. (line 1025)
* WNOWAIT (in module os):                Process Management. (line 1033)
* wordchars (shlex.shlex attribute):     shlex Objects.      (line   91)
* World Wide Web:                        Internet Protocols and Support.
                                                             (line    6)
* World Wide Web <1>:                    urllib parse — Parse URLs into components.
                                                             (line    8)
* World Wide Web <2>:                    urllib robotparser — Parser for robots txt.
                                                             (line    8)
* wrap_bio() (ssl.SSLContext method):    SSL contexts.       (line  454)
* wrap_future() (in module asyncio):     Future Functions.   (line   51)
* wrap_socket() (ssl.SSLContext method): SSL contexts.       (line  387)
* wrap() (in module textwrap):           textwrap — Text wrapping and filling.
                                                             (line   16)
* wrap() (textwrap.TextWrapper method):  textwrap — Text wrapping and filling.
                                                             (line  284)
* wrapper() (in module curses):          Functions<6>.       (line  607)
* WrapperDescriptorType (in module types): Standard Interpreter Types.
                                                             (line   88)
* wraps() (in module functools):         functools — Higher-order functions and operations on callable objects.
                                                             (line  695)
* WRITABLE (in module _tkinter):         File Handlers.      (line   41)
* WRITABLE (inspect.BufferFlags attribute): Buffer flags.    (line   17)
* writable() (bz2.BZ2File method):       De compression of files.
                                                             (line  104)
* writable() (io.IOBase method):         I/O Base Classes.   (line  151)
* WRITE (inspect.BufferFlags attribute): Buffer flags.       (line   51)
* write_byte() (mmap.mmap method):       mmap — Memory-mapped file support.
                                                             (line  337)
* write_bytes() (pathlib.Path method):   Reading and writing files.
                                                             (line   67)
* write_docstringdict() (in module turtle): Translation of docstrings into different languages.
                                                             (line   10)
* write_eof() (asyncio.StreamWriter method): StreamWriter.   (line   55)
* write_eof() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   74)
* write_eof() (ssl.MemoryBIO method):    Memory BIO support. (line  161)
* write_history_file() (in module readline): History file.   (line   14)
* WRITE_RESTRICTED (C macro):            Member flags.       (line   31)
* write_results() (trace.CoverageResults method): Programmatic Interface.
                                                             (line   56)
* write_text() (pathlib.Path method):    Reading and writing files.
                                                             (line   48)
* write_through (io.TextIOWrapper attribute): Text I/O<2>.   (line  174)
* write() (asyncio.StreamWriter method): StreamWriter.       (line   15)
* write() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   60)
* write() (code.InteractiveInterpreter method): Interactive Interpreter Objects.
                                                             (line   63)
* write() (codecs.StreamWriter method):  StreamWriter Objects.
                                                             (line   31)
* write() (configparser.ConfigParser method): ConfigParser Objects.
                                                             (line  292)
* write() (email.generator.BytesGenerator method): email generator Generating MIME documents.
                                                             (line  117)
* write() (email.generator.Generator method): email generator Generating MIME documents.
                                                             (line  210)
* write() (file method):                 I/O objects also known as file objects.
                                                             (line   27)
* write() (in module os):                File Descriptor Operations.
                                                             (line  919)
* write() (in module turtle):            More drawing control.
                                                             (line   29)
* write() (io.BufferedIOBase method):    I/O Base Classes.   (line  332)
* write() (io.BufferedWriter method):    Buffered Streams.   (line  124)
* write() (io.RawIOBase method):         I/O Base Classes.   (line  211)
* write() (io.TextIOBase method):        Text I/O<2>.        (line   93)
* write() (mmap.mmap method):            mmap — Memory-mapped file support.
                                                             (line  321)
* write() (sqlite3.Blob method):         Blob objects.       (line   53)
* write() (ssl.MemoryBIO method):        Memory BIO support. (line  153)
* write() (ssl.SSLSocket method):        SSL sockets.        (line   95)
* write() (xml.etree.ElementTree.ElementTree method): ElementTree Objects.
                                                             (line   62)
* write() (zipfile.ZipFile method):      ZipFile objects.    (line  271)
* writeframes() (wave.Wave_write method): Wave_write Objects.
                                                             (line  113)
* writeframesraw() (wave.Wave_write method): Wave_write Objects.
                                                             (line  106)
* writeheader() (csv.DictWriter method): Writer Objects.     (line   38)
* writelines() (asyncio.StreamWriter method): StreamWriter.  (line   29)
* writelines() (asyncio.WriteTransport method): Write-only Transports.
                                                             (line   67)
* writelines() (codecs.StreamWriter method): StreamWriter Objects.
                                                             (line   35)
* writelines() (io.IOBase method):       I/O Base Classes.   (line  157)
* writepy() (zipfile.PyZipFile method):  PyZipFile objects.  (line   20)
* writer() (in module csv):              Module Contents<2>. (line   39)
* writerow() (csv.csvwriter method):     Writer Objects.     (line   15)
* writerows() (csv.csvwriter method):    Writer Objects.     (line   24)
* writestr() (zipfile.ZipFile method):   ZipFile objects.    (line  306)
* WriteTransport (class in asyncio):     Transports Hierarchy.
                                                             (line   11)
* writev() (in module os):               File Descriptor Operations.
                                                             (line  939)
* writexml() (xml.dom.minidom.Node method): DOM Objects.     (line   27)
* writing; values:                       Expression statements.
                                                             (line   17)
* WrongDocumentErr:                      Exceptions<20>.     (line   97)
* wsgi_file_wrapper (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  272)
* wsgi_multiprocess (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  154)
* wsgi_multithread (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  147)
* wsgi_run_once (wsgiref.handlers.BaseHandler attribute): wsgiref handlers – server/gateway base classes.
                                                             (line  161)
* WSGIApplication (in module wsgiref.types): wsgiref types – WSGI types for static type checking.
                                                             (line   20)
* WSGIEnvironment (in module wsgiref.types): wsgiref types – WSGI types for static type checking.
                                                             (line   16)
* WSGIRequestHandler (class in wsgiref.simple_server): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   77)
* WSGIServer (class in wsgiref.simple_server): wsgiref simple_server – a simple WSGI HTTP server.
                                                             (line   47)
* wShowWindow (subprocess.STARTUPINFO attribute): Windows Popen Helpers.
                                                             (line   48)
* WSTOPPED (in module os):               Process Management. (line 1003)
* WSTOPSIG() (in module os):             Process Management. (line 1155)
* wstring_at() (in module ctypes):       Utility functions.  (line  250)
* WTERMSIG() (in module os):             Process Management. (line 1164)
* WUNTRACED (in module os):              Process Management. (line 1014)
* WWW:                                   Internet Protocols and Support.
                                                             (line    6)
* WWW <1>:                               urllib parse — Parse URLs into components.
                                                             (line    8)
* WWW <2>:                               urllib robotparser — Parser for robots txt.
                                                             (line    8)
* WWW; server:                           http server — HTTP servers.
                                                             (line    8)
* X (in module re):                      Flags.              (line  127)
* X_OK (in module os):                   Files and Directories.
                                                             (line  107)
* X509 certificate:                      SSL contexts.       (line  759)
* xatom() (imaplib.IMAP4 method):        IMAP4 Objects.      (line  388)
* XATTR_CREATE (in module os):           Linux extended attributes.
                                                             (line   88)
* XATTR_REPLACE (in module os):          Linux extended attributes.
                                                             (line   94)
* XATTR_SIZE_MAX (in module os):         Linux extended attributes.
                                                             (line   83)
* xcor() (in module turtle):             Tell Turtle’s state.
                                                             (line   34)
* XHTML:                                 html parser — Simple HTML and XHTML parser.
                                                             (line    8)
* XHTML_NAMESPACE (in module xml.dom):   Module Contents<3>. (line   53)
* XML_ERROR_ABORTED (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  180)
* XML_ERROR_AMPLIFICATION_LIMIT_BREACH (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  215)
* XML_ERROR_ASYNC_ENTITY (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   29)
* XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   31)
* XML_ERROR_BAD_CHAR_REF (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   37)
* XML_ERROR_BINARY_ENTITY_REF (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   42)
* XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  135)
* XML_ERROR_DUPLICATE_ATTRIBUTE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   47)
* XML_ERROR_ENTITY_DECLARED_IN_PE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  126)
* XML_ERROR_EXTERNAL_ENTITY_HANDLING (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  116)
* XML_ERROR_FEATURE_REQUIRES_XML_DTD (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  128)
* XML_ERROR_FINISHED (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  184)
* XML_ERROR_INCOMPLETE_PE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  152)
* XML_ERROR_INCORRECT_ENCODING (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   51)
* XML_ERROR_INVALID_ARGUMENT (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  207)
* XML_ERROR_INVALID_TOKEN (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   53)
* XML_ERROR_JUNK_AFTER_DOC_ELEMENT (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   59)
* XML_ERROR_MISPLACED_XML_PI (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   64)
* XML_ERROR_NO_BUFFER (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  211)
* XML_ERROR_NO_ELEMENTS (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   69)
* XML_ERROR_NO_MEMORY (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   74)
* XML_ERROR_NOT_STANDALONE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  118)
* XML_ERROR_NOT_SUSPENDED (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  175)
* XML_ERROR_PARAM_ENTITY_REF (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   78)
* XML_ERROR_PARTIAL_CHAR (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   82)
* XML_ERROR_PUBLICID (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  165)
* XML_ERROR_RECURSIVE_ENTITY_REF (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   86)
* XML_ERROR_RESERVED_NAMESPACE_URI (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  202)
* XML_ERROR_RESERVED_PREFIX_XML (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  192)
* XML_ERROR_RESERVED_PREFIX_XMLNS (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  197)
* XML_ERROR_SUSPEND_PE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  190)
* XML_ERROR_SUSPENDED (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  169)
* XML_ERROR_SYNTAX (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   91)
* XML_ERROR_TAG_MISMATCH (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   95)
* XML_ERROR_TEXT_DECL (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  160)
* XML_ERROR_UNBOUND_PREFIX (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  142)
* XML_ERROR_UNCLOSED_CDATA_SECTION (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  112)
* XML_ERROR_UNCLOSED_TOKEN (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line   99)
* XML_ERROR_UNDECLARING_PREFIX (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  147)
* XML_ERROR_UNDEFINED_ENTITY (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  104)
* XML_ERROR_UNEXPECTED_STATE (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  124)
* XML_ERROR_UNKNOWN_ENCODING (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  108)
* XML_ERROR_XML_DECL (in module xml.parsers.expat.errors): Expat error constants.
                                                             (line  156)
* XML_NAMESPACE (in module xml.dom):     Module Contents<3>. (line   42)
* XML() (in module xml.etree.ElementTree): Functions<9>.     (line  269)
* xmlcharrefreplace_errors() (in module codecs): Error Handlers.
                                                             (line  172)
* xmlcharrefreplace; error handler's name: Error Handlers.   (line   54)
* XmlDeclHandler() (xml.parsers.expat.xmlparser method): XMLParser Objects<2>.
                                                             (line  262)
* XMLFilterBase (class in xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   72)
* XMLGenerator (class in xml.sax.saxutils): xml sax saxutils — SAX Utilities.
                                                             (line   56)
* XMLID() (in module xml.etree.ElementTree): Functions<9>.   (line  277)
* XMLNS_NAMESPACE (in module xml.dom):   Module Contents<3>. (line   47)
* XMLParser (class in xml.etree.ElementTree): XMLParser Objects.
                                                             (line    6)
* XMLParserType (in module xml.parsers.expat): xml parsers expat — Fast XML parsing using Expat.
                                                             (line   34)
* XMLPullParser (class in xml.etree.ElementTree): XMLPullParser Objects.
                                                             (line    6)
* XMLReader (class in xml.sax.xmlreader): xml sax xmlreader — Interface for XML parsers.
                                                             (line   16)
* xor() (in module operator):            operator — Standard operators as functions.
                                                             (line  168)
* xview() (tkinter.ttk.Treeview method): ttk Treeview.       (line  317)
* ycor() (in module turtle):             Tell Turtle’s state.
                                                             (line   46)
* year (datetime.date attribute):        date Objects.       (line  116)
* year (datetime.datetime attribute):    datetime Objects.   (line  304)
* Year 2038:                             time — Time access and conversions.
                                                             (line   29)
* yeardatescalendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  127)
* yeardays2calendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  135)
* yeardayscalendar() (calendar.Calendar method): calendar — General calendar-related functions.
                                                             (line  142)
* YES (in module tkinter.messagebox):    tkinter messagebox — Tkinter message prompts.
                                                             (line  157)
* YESEXPR (in module locale):            locale — Internationalization services.
                                                             (line  288)
* YESNO (in module tkinter.messagebox):  tkinter messagebox — Tkinter message prompts.
                                                             (line  181)
* YESNOCANCEL (in module tkinter.messagebox): tkinter messagebox — Tkinter message prompts.
                                                             (line  186)
* Yield (class in ast):                  Function and class definitions.
                                                             (line  124)
* YIELD_VALUE (opcode):                  Python Bytecode Instructions.
                                                             (line  420)
* yield; examples:                       Generator-iterator methods.
                                                             (line   81)
* yield; expression:                     Yield expressions.  (line    6)
* yield; yield from (in What's New):     PEP 3151 Reworking the OS and IO exception hierarchy.
                                                             (line   87)
* YieldFrom (class in ast):              Function and class definitions.
                                                             (line  124)
* yiq_to_rgb() (in module colorsys):     colorsys — Conversions between color systems.
                                                             (line   32)
* yview() (tkinter.ttk.Treeview method): ttk Treeview.       (line  321)
* Z_BEST_COMPRESSION (in module zlib):   zlib — Compression compatible with gzip.
                                                             (line  332)
* Z_BEST_SPEED (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  328)
* Z_BLOCK (in module zlib):              zlib — Compression compatible with gzip.
                                                             (line  398)
* Z_DEFAULT_COMPRESSION (in module zlib): zlib — Compression compatible with gzip.
                                                             (line  336)
* Z_DEFAULT_STRATEGY (in module zlib):   zlib — Compression compatible with gzip.
                                                             (line  341)
* Z_FILTERED (in module zlib):           zlib — Compression compatible with gzip.
                                                             (line  345)
* Z_FINISH (in module zlib):             zlib — Compression compatible with gzip.
                                                             (line  393)
* Z_FIXED (in module zlib):              zlib — Compression compatible with gzip.
                                                             (line  363)
* Z_FULL_FLUSH (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  388)
* Z_HUFFMAN_ONLY (in module zlib):       zlib — Compression compatible with gzip.
                                                             (line  349)
* Z_NO_COMPRESSION (in module zlib):     zlib — Compression compatible with gzip.
                                                             (line  322)
* Z_NO_FLUSH (in module zlib):           zlib — Compression compatible with gzip.
                                                             (line  373)
* Z_PARTIAL_FLUSH (in module zlib):      zlib — Compression compatible with gzip.
                                                             (line  379)
* Z_RLE (in module zlib):                zlib — Compression compatible with gzip.
                                                             (line  353)
* Z_SYNC_FLUSH (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  383)
* Z_TREES (in module zlib):              zlib — Compression compatible with gzip.
                                                             (line  407)
* z; in string formatting:               Format specification mini-language.
                                                             (line   90)
* z85decode() (in module base64):        Base85 Encodings.   (line  100)
* z85encode() (in module base64):        Base85 Encodings.   (line   92)
* Zen of Python:                         Glossary.           (line 1787)
* ZeroDivisionError:                     Concrete exceptions.
                                                             (line  485)
* zfill() (bytearray method):            Bytes and Bytearray Operations.
                                                             (line  749)
* zfill() (bytes method):                Bytes and Bytearray Operations.
                                                             (line  749)
* zfill() (str method):                  String Methods<2>.  (line  949)
* ZIP_BZIP2 (in module zipfile):         zipfile — Work with ZIP archives.
                                                             (line   93)
* ZIP_DEFLATED (in module zipfile):      zipfile — Work with ZIP archives.
                                                             (line   88)
* zip_longest() (in module itertools):   Itertool Functions. (line  656)
* ZIP_LZMA (in module zipfile):          zipfile — Work with ZIP archives.
                                                             (line  100)
* ZIP_STORED (in module zipfile):        zipfile — Work with ZIP archives.
                                                             (line   84)
* zipapp command line option; -c:        Command-Line Interface<4>.
                                                             (line   45)
* zipapp command line option; -compress: Command-Line Interface<4>.
                                                             (line   45)
* zipapp command line option; -h:        Command-Line Interface<4>.
                                                             (line   61)
* zipapp command line option; -help:     Command-Line Interface<4>.
                                                             (line   61)
* zipapp command line option; -info:     Command-Line Interface<4>.
                                                             (line   55)
* zipapp command line option; -m:        Command-Line Interface<4>.
                                                             (line   35)
* zipapp command line option; -main:     Command-Line Interface<4>.
                                                             (line   35)
* zipapp command line option; -o:        Command-Line Interface<4>.
                                                             (line   18)
* zipapp command line option; -output:   Command-Line Interface<4>.
                                                             (line   18)
* zipapp command line option; -p:        Command-Line Interface<4>.
                                                             (line   29)
* zipapp command line option; -python:   Command-Line Interface<4>.
                                                             (line   29)
* ZipFile (class in zipfile):            ZipFile objects.    (line    6)
* zipfile command line option; -c:       Command-line options<2>.
                                                             (line   11)
* zipfile command line option; -create:  Command-line options<2>.
                                                             (line   11)
* zipfile command line option; -e:       Command-line options<2>.
                                                             (line   16)
* zipfile command line option; -extract: Command-line options<2>.
                                                             (line   16)
* zipfile command line option; -l:       Command-line options<2>.
                                                             (line    6)
* zipfile command line option; -list:    Command-line options<2>.
                                                             (line    6)
* zipfile command line option; -metadata-encoding: Command-line options<2>.
                                                             (line   26)
* zipfile command line option; -t:       Command-line options<2>.
                                                             (line   21)
* zipfile command line option; -test:    Command-line options<2>.
                                                             (line   21)
* zipimporter (class in zipimport):      zipimporter Objects.
                                                             (line    8)
* ZipImportError:                        zipimport — Import modules from Zip archives.
                                                             (line   58)
* ZipInfo (class in zipfile):            zipfile — Work with ZIP archives.
                                                             (line   58)
* ZLIB_RUNTIME_VERSION (in module zlib): zlib — Compression compatible with gzip.
                                                             (line  427)
* ZLIB_VERSION (in module zlib):         zlib — Compression compatible with gzip.
                                                             (line  420)
* ZoneInfo (class in zoneinfo):          The ZoneInfo class. (line    6)
* ZoneInfoNotFoundError:                 Exceptions and warnings.
                                                             (line    6)
* zscore() (statistics.NormalDist method): NormalDist objects.
                                                             (line  120)

                                                           



Tag Table:
Node: Top354
Ref: contents doc565
Ref: 135565
Node: What’s New in Python234812
Ref: whatsnew/index doc234914
Ref: 136234914
Ref: whatsnew/index python-documentation-contents234914
Ref: 137234914
Ref: whatsnew/index what-s-new-in-python234914
Ref: 138234914
Ref: whatsnew/index whatsnew-index234914
Ref: 139234914
Node: What’s New In Python 3 13236487
Ref: whatsnew/3 13 doc236609
Ref: 13a236609
Ref: whatsnew/3 13 what-s-new-in-python-3-13236609
Ref: 13b236609
Ref: What’s New In Python 3 13-Footnote-1237431
Node: Summary – Release Highlights237473
Ref: whatsnew/3 13 summary-release-highlights237588
Ref: 13d237588
Ref: whatsnew/3 13 whatsnew313-better-interactive-interpreter237892
Ref: 13e237892
Ref: whatsnew/3 13 whatsnew313-free-threaded-cpython237962
Ref: 13f237962
Ref: whatsnew/3 13 whatsnew313-jit-compiler238016
Ref: 140238016
Ref: whatsnew/3 13 whatsnew313-pep594238490
Ref: 143238490
Ref: Summary – Release Highlights-Footnote-1244419
Ref: Summary – Release Highlights-Footnote-2244461
Ref: Summary – Release Highlights-Footnote-3244503
Ref: Summary – Release Highlights-Footnote-4244545
Ref: Summary – Release Highlights-Footnote-5244587
Ref: Summary – Release Highlights-Footnote-6244629
Ref: Summary – Release Highlights-Footnote-7244671
Ref: Summary – Release Highlights-Footnote-8244701
Ref: Summary – Release Highlights-Footnote-9244741
Ref: Summary – Release Highlights-Footnote-10244783
Ref: Summary – Release Highlights-Footnote-11244826
Ref: Summary – Release Highlights-Footnote-12244869
Ref: Summary – Release Highlights-Footnote-13244912
Ref: Summary – Release Highlights-Footnote-14244955
Ref: Summary – Release Highlights-Footnote-15244998
Ref: Summary – Release Highlights-Footnote-16245048
Ref: Summary – Release Highlights-Footnote-17245091
Ref: Summary – Release Highlights-Footnote-18245141
Ref: Summary – Release Highlights-Footnote-19245191
Node: New Features245234
Ref: whatsnew/3 13 new-features245380
Ref: 167245380
Node: A better interactive interpreter245725
Ref: whatsnew/3 13 a-better-interactive-interpreter245838
Ref: 168245838
Ref: A better interactive interpreter-Footnote-1247156
Ref: A better interactive interpreter-Footnote-2247182
Node: Improved error messages247238
Ref: whatsnew/3 13 improved-error-messages247381
Ref: 170247381
Ref: whatsnew/3 13 whatsnew313-improved-error-messages247381
Ref: 147247381
Ref: Improved error messages-Footnote-1249825
Ref: Improved error messages-Footnote-2249855
Ref: Improved error messages-Footnote-3249888
Ref: Improved error messages-Footnote-4249944
Ref: Improved error messages-Footnote-5249999
Node: Free-threaded CPython250055
Ref: whatsnew/3 13 free-threaded-cpython250207
Ref: 171250207
Ref: Free-threaded CPython-Footnote-1253211
Ref: Free-threaded CPython-Footnote-2253253
Node: An experimental just-in-time JIT compiler253306
Ref: whatsnew/3 13 an-experimental-just-in-time-jit-compiler253472
Ref: 17a253472
Ref: An experimental just-in-time JIT compiler-Footnote-1256108
Ref: An experimental just-in-time JIT compiler-Footnote-2256180
Node: Defined mutation semantics for locals256222
Ref: whatsnew/3 13 defined-mutation-semantics-for-locals256395
Ref: 17d256395
Ref: whatsnew/3 13 whatsnew313-locals-semantics256395
Ref: 142256395
Ref: Defined mutation semantics for locals-Footnote-1259008
Ref: Defined mutation semantics for locals-Footnote-2259050
Ref: Defined mutation semantics for locals-Footnote-3259092
Node: Support for mobile platforms259147
Ref: whatsnew/3 13 support-for-mobile-platforms259270
Ref: 185259270
Ref: whatsnew/3 13 whatsnew313-platform-support259270
Ref: 165259270
Ref: Support for mobile platforms-Footnote-1260317
Ref: Support for mobile platforms-Footnote-2260359
Ref: Support for mobile platforms-Footnote-3260401
Ref: Support for mobile platforms-Footnote-4260457
Ref: Support for mobile platforms-Footnote-5260499
Ref: Support for mobile platforms-Footnote-6260541
Ref: Support for mobile platforms-Footnote-7260597
Ref: Support for mobile platforms-Footnote-8260639
Node: Other Language Changes260681
Ref: whatsnew/3 13 other-language-changes260808
Ref: 186260808
Ref: Other Language Changes-Footnote-1265635
Ref: Other Language Changes-Footnote-2265690
Ref: Other Language Changes-Footnote-3265746
Ref: Other Language Changes-Footnote-4265802
Ref: Other Language Changes-Footnote-5265858
Ref: Other Language Changes-Footnote-6265914
Ref: Other Language Changes-Footnote-7265970
Ref: Other Language Changes-Footnote-8266019
Ref: Other Language Changes-Footnote-9266075
Ref: Other Language Changes-Footnote-10266130
Ref: Other Language Changes-Footnote-11266187
Ref: Other Language Changes-Footnote-12266244
Ref: Other Language Changes-Footnote-13266301
Ref: Other Language Changes-Footnote-14266358
Ref: Other Language Changes-Footnote-15266415
Ref: Other Language Changes-Footnote-16266472
Ref: Other Language Changes-Footnote-17266529
Ref: Other Language Changes-Footnote-18266585
Node: New Modules266642
Ref: whatsnew/3 13 new-modules266773
Ref: 19b266773
Ref: New Modules-Footnote-1266997
Node: Improved Modules267053
Ref: whatsnew/3 13 improved-modules267175
Ref: 19c267175
Node: argparse267845
Ref: whatsnew/3 13 argparse267920
Ref: 19d267920
Ref: argparse-Footnote-1268243
Node: array268298
Ref: whatsnew/3 13 array268385
Ref: 19f268385
Ref: array-Footnote-1268821
Ref: array-Footnote-2268876
Node: ast268932
Ref: whatsnew/3 13 ast269018
Ref: 1a3269018
Ref: ast-Footnote-1270578
Ref: ast-Footnote-2270634
Ref: ast-Footnote-3270690
Ref: ast-Footnote-4270746
Node: asyncio270802
Ref: whatsnew/3 13 asyncio270889
Ref: 1a9270889
Ref: asyncio-Footnote-1274651
Ref: asyncio-Footnote-2274706
Ref: asyncio-Footnote-3274762
Ref: asyncio-Footnote-4274818
Ref: asyncio-Footnote-5274874
Ref: asyncio-Footnote-6274930
Ref: asyncio-Footnote-7274985
Ref: asyncio-Footnote-8275041
Ref: asyncio-Footnote-9275097
Node: base64275153
Ref: whatsnew/3 13 base64275247
Ref: 1c1275247
Ref: base64-Footnote-1275542
Ref: base64-Footnote-2275582
Node: compileall275637
Ref: whatsnew/3 13 compileall275742
Ref: 1c3275742
Ref: compileall-Footnote-1276034
Node: concurrent futures276090
Ref: whatsnew/3 13 concurrent-futures276201
Ref: 1c6276201
Ref: concurrent futures-Footnote-1276509
Node: configparser276565
Ref: whatsnew/3 13 configparser276670
Ref: 1c7276670
Ref: configparser-Footnote-1277000
Node: copy277055
Ref: whatsnew/3 13 copy277148
Ref: 1c9277148
Ref: copy-Footnote-1278059
Node: ctypes278115
Ref: whatsnew/3 13 ctypes278199
Ref: 1d3278199
Ref: ctypes-Footnote-1279134
Ref: ctypes-Footnote-2279190
Node: dbm279246
Ref: whatsnew/3 13 dbm279329
Ref: 1d6279329
Ref: dbm-Footnote-1279783
Ref: dbm-Footnote-2279839
Node: dis279895
Ref: whatsnew/3 13 dis279979
Ref: 1d7279979
Ref: dis-Footnote-1280727
Ref: dis-Footnote-2280783
Node: doctest280839
Ref: whatsnew/3 13 doctest280925
Ref: 1db280925
Ref: whatsnew/3 13 whatsnew313-doctest280925
Ref: 149280925
Ref: doctest-Footnote-1281572
Ref: doctest-Footnote-2281602
Ref: doctest-Footnote-3281635
Ref: doctest-Footnote-4281691
Node: email281747
Ref: whatsnew/3 13 email281834
Ref: 1df281834
Ref: email-Footnote-1282966
Ref: email-Footnote-2283022
Ref: email-Footnote-3283078
Node: enum283134
Ref: whatsnew/3 13 enum283223
Ref: 1e3283223
Node: fractions283356
Ref: whatsnew/3 13 fractions283444
Ref: 1e6283444
Ref: fractions-Footnote-1283762
Node: glob283818
Ref: whatsnew/3 13 glob283911
Ref: 1e9283911
Ref: glob-Footnote-1284160
Node: importlib284215
Ref: whatsnew/3 13 importlib284301
Ref: 1eb284301
Ref: importlib-Footnote-1285202
Ref: importlib-Footnote-2285258
Node: io285314
Ref: whatsnew/3 13 io285405
Ref: 1f4285405
Ref: io-Footnote-1285831
Node: ipaddress285886
Ref: whatsnew/3 13 ipaddress285977
Ref: 1fa285977
Ref: ipaddress-Footnote-1286436
Ref: ipaddress-Footnote-2286492
Node: itertools286548
Ref: whatsnew/3 13 itertools286644
Ref: 200286644
Ref: itertools-Footnote-1286944
Node: marshal287000
Ref: whatsnew/3 13 marshal287091
Ref: 203287091
Ref: marshal-Footnote-1287426
Node: math287482
Ref: whatsnew/3 13 math287573
Ref: 204287573
Ref: math-Footnote-1288068
Node: mimetypes288123
Ref: whatsnew/3 13 mimetypes288211
Ref: 206288211
Ref: mimetypes-Footnote-1288528
Node: mmap288583
Ref: whatsnew/3 13 mmap288682
Ref: 20a288682
Ref: mmap-Footnote-1289495
Ref: mmap-Footnote-2289551
Ref: mmap-Footnote-3289607
Node: multiprocessing289662
Ref: whatsnew/3 13 multiprocessing289754
Ref: 20e289754
Ref: multiprocessing-Footnote-1290058
Node: os290114
Ref: whatsnew/3 13 os290209
Ref: 20f290209
Ref: os-Footnote-1292677
Ref: os-Footnote-2292733
Ref: os-Footnote-3292789
Ref: os-Footnote-4292843
Ref: os-Footnote-5292899
Ref: os-Footnote-6292954
Ref: os-Footnote-7293010
Ref: os-Footnote-8293065
Ref: os-Footnote-9293121
Ref: os-Footnote-10293177
Node: os path293234
Ref: whatsnew/3 13 os-path293321
Ref: 222293321
Ref: os path-Footnote-1293944
Ref: os path-Footnote-2293999
Ref: os path-Footnote-3294054
Node: pathlib294109
Ref: whatsnew/3 13 pathlib294197
Ref: 226294197
Ref: pathlib-Footnote-1295725
Ref: pathlib-Footnote-2295780
Ref: pathlib-Footnote-3295836
Ref: pathlib-Footnote-4295891
Ref: pathlib-Footnote-5295946
Ref: pathlib-Footnote-6296001
Ref: pathlib-Footnote-7296057
Node: pdb296113
Ref: whatsnew/3 13 pdb296199
Ref: 233296199
Ref: pdb-Footnote-1297334
Ref: pdb-Footnote-2297390
Ref: pdb-Footnote-3297446
Ref: pdb-Footnote-4297502
Ref: pdb-Footnote-5297558
Node: queue297614
Ref: whatsnew/3 13 queue297699
Ref: 239297699
Ref: queue-Footnote-1297934
Node: random297990
Ref: whatsnew/3 13 random298074
Ref: 23c298074
Ref: random-Footnote-1298248
Node: re298304
Ref: whatsnew/3 13 re298389
Ref: 23d298389
Node: shutil298548
Ref: whatsnew/3 13 shutil298631
Ref: 23f298631
Ref: shutil-Footnote-1298859
Node: site298914
Ref: whatsnew/3 13 site299002
Ref: 241299002
Ref: site-Footnote-1299253
Node: sqlite3299309
Ref: whatsnew/3 13 sqlite3299394
Ref: 243299394
Ref: sqlite3-Footnote-1299835
Ref: sqlite3-Footnote-2299891
Node: ssl299946
Ref: whatsnew/3 13 ssl300037
Ref: 248300037
Ref: ssl-Footnote-1300726
Ref: ssl-Footnote-2300785
Node: statistics300841
Ref: whatsnew/3 13 statistics300935
Ref: 249300935
Ref: statistics-Footnote-1301444
Ref: statistics-Footnote-2301500
Node: subprocess301556
Ref: whatsnew/3 13 subprocess301650
Ref: 24c301650
Ref: whatsnew/3 13 whatsnew313-subprocess301650
Ref: 24d301650
Ref: subprocess-Footnote-1302590
Node: sys302646
Ref: whatsnew/3 13 sys302738
Ref: 24f302738
Ref: sys-Footnote-1303027
Node: tempfile303082
Ref: whatsnew/3 13 tempfile303168
Ref: 251303168
Ref: tempfile-Footnote-1303513
Ref: tempfile-Footnote-2303568
Node: time303624
Ref: whatsnew/3 13 time303714
Ref: 252303714
Ref: time-Footnote-1304362
Ref: time-Footnote-2304417
Node: tkinter304472
Ref: whatsnew/3 13 tkinter304563
Ref: 255304563
Ref: tkinter-Footnote-1306831
Ref: tkinter-Footnote-2306886
Ref: tkinter-Footnote-3306941
Ref: tkinter-Footnote-4306996
Ref: tkinter-Footnote-5307051
Ref: tkinter-Footnote-6307106
Ref: tkinter-Footnote-7307161
Ref: tkinter-Footnote-8307217
Ref: tkinter-Footnote-9307273
Node: traceback307329
Ref: whatsnew/3 13 traceback307421
Ref: 25a307421
Ref: traceback-Footnote-1308151
Ref: traceback-Footnote-2308207
Node: types308263
Ref: whatsnew/3 13 types308354
Ref: 260308354
Ref: types-Footnote-1308681
Node: typing308737
Ref: whatsnew/3 13 typing308830
Ref: 261308830
Ref: typing-Footnote-1309816
Ref: typing-Footnote-2309858
Ref: typing-Footnote-3309900
Ref: typing-Footnote-4309956
Ref: typing-Footnote-5310012
Ref: typing-Footnote-6310068
Node: unicodedata310123
Ref: whatsnew/3 13 unicodedata310215
Ref: 268310215
Ref: unicodedata-Footnote-1310403
Ref: unicodedata-Footnote-2310459
Node: venv310515
Ref: whatsnew/3 13 venv310609
Ref: 269310609
Ref: venv-Footnote-1311103
Node: warnings311159
Ref: whatsnew/3 13 warnings311245
Ref: 26c311245
Ref: warnings-Footnote-1311709
Ref: warnings-Footnote-2311751
Node: xml311807
Ref: whatsnew/3 13 xml311898
Ref: 26e311898
Ref: xml-Footnote-1312664
Ref: xml-Footnote-2312720
Ref: xml-Footnote-3312776
Node: zipimport312831
Ref: whatsnew/3 13 zipimport312905
Ref: 274312905
Ref: zipimport-Footnote-1313109
Ref: zipimport-Footnote-2313171
Node: Optimizations313226
Ref: whatsnew/3 13 optimizations313361
Ref: 275313361
Ref: Optimizations-Footnote-1314568
Ref: Optimizations-Footnote-2314624
Ref: Optimizations-Footnote-3314680
Node: Removed Modules And APIs314736
Ref: whatsnew/3 13 removed-modules-and-apis314871
Ref: 277314871
Node: PEP 594 Remove “dead batteries” from the standard library315340
Ref: whatsnew/3 13 pep-594-remove-dead-batteries-from-the-standard-library315475
Ref: 278315475
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-1320741
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-2320783
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-3320831
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-4320877
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-5320926
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-6320970
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-7321014
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-8321061
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-9321110
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-10321151
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-11321198
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-12321245
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-13321288
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-14321336
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-15321386
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-16321450
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-17321494
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-18321539
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-19321587
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-20321638
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-21321690
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-22321732
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-23321784
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-24321826
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-25321876
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-26321920
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-27321965
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-28322013
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-29322064
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-30322110
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-31322160
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-32322206
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-33322250
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-34322304
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-35322351
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-36322402
Ref: PEP 594 Remove “dead batteries” from the standard library-Footnote-37322459
Node: 2to3322516
Ref: whatsnew/3 13 to3322668
Ref: 27e322668
Ref: 2to3-Footnote-1322895
Node: builtins322951
Ref: whatsnew/3 13 builtins323057
Ref: 27f323057
Ref: builtins-Footnote-1323798
Ref: builtins-Footnote-2323853
Ref: builtins-Footnote-3323908
Node: configparser<2>323963
Ref: whatsnew/3 13 id3324083
Ref: 281324083
Ref: configparser<2>-Footnote-1324367
Node: importlib metadata324423
Ref: whatsnew/3 13 importlib-metadata324541
Ref: 282324541
Ref: importlib metadata-Footnote-1324798
Node: locale324854
Ref: whatsnew/3 13 locale324963
Ref: 285324963
Ref: locale-Footnote-1325226
Node: opcode325282
Ref: whatsnew/3 13 opcode325381
Ref: 286325381
Ref: opcode-Footnote-1326006
Ref: opcode-Footnote-2326062
Node: optparse326118
Ref: whatsnew/3 13 optparse326221
Ref: 287326221
Ref: optparse-Footnote-1327011
Node: pathlib<2>327067
Ref: whatsnew/3 13 id4327169
Ref: 288327169
Ref: pathlib<2>-Footnote-1327447
Node: re<2>327502
Ref: whatsnew/3 13 id5327607
Ref: 289327607
Ref: re<2>-Footnote-1327873
Node: tkinter tix327929
Ref: whatsnew/3 13 tkinter-tix328030
Ref: 28a328030
Ref: tkinter tix-Footnote-1328305
Node: turtle328360
Ref: whatsnew/3 13 turtle328465
Ref: 28b328465
Ref: turtle-Footnote-1328735
Node: typing<2>328791
Ref: whatsnew/3 13 id6328893
Ref: 28c328893
Ref: typing<2>-Footnote-1329379
Ref: typing<2>-Footnote-2329434
Node: unittest329490
Ref: whatsnew/3 13 unittest329592
Ref: 28d329592
Ref: unittest-Footnote-1330294
Ref: unittest-Footnote-2330350
Node: urllib330406
Ref: whatsnew/3 13 urllib330509
Ref: 292330509
Ref: urllib-Footnote-1331116
Node: webbrowser331172
Ref: whatsnew/3 13 webbrowser331258
Ref: 296331258
Ref: webbrowser-Footnote-1331749
Ref: webbrowser-Footnote-2331805
Node: New Deprecations331861
Ref: whatsnew/3 13 new-deprecations332007
Ref: 298332007
Ref: New Deprecations-Footnote-1340491
Ref: New Deprecations-Footnote-2340546
Ref: New Deprecations-Footnote-3340601
Ref: New Deprecations-Footnote-4340657
Ref: New Deprecations-Footnote-5340713
Ref: New Deprecations-Footnote-6340768
Ref: New Deprecations-Footnote-7340824
Ref: New Deprecations-Footnote-8340879
Ref: New Deprecations-Footnote-9340935
Ref: New Deprecations-Footnote-10340991
Ref: New Deprecations-Footnote-11341048
Ref: New Deprecations-Footnote-12341104
Ref: New Deprecations-Footnote-13341160
Ref: New Deprecations-Footnote-14341216
Ref: New Deprecations-Footnote-15341273
Ref: New Deprecations-Footnote-16341329
Ref: New Deprecations-Footnote-17341386
Ref: New Deprecations-Footnote-18341443
Ref: New Deprecations-Footnote-19341500
Ref: New Deprecations-Footnote-20341556
Ref: New Deprecations-Footnote-21341613
Ref: New Deprecations-Footnote-22341670
Ref: New Deprecations-Footnote-23341727
Ref: New Deprecations-Footnote-24341784
Ref: New Deprecations-Footnote-25341841
Ref: New Deprecations-Footnote-26341898
Ref: New Deprecations-Footnote-27341955
Node: Pending Removal in Python 3 14342012
Ref: whatsnew/3 13 pending-removal-in-python-3-14342134
Ref: 2b8342134
Ref: Pending Removal in Python 3 14-Footnote-1346596
Ref: Pending Removal in Python 3 14-Footnote-2346651
Ref: Pending Removal in Python 3 14-Footnote-3346706
Ref: Pending Removal in Python 3 14-Footnote-4346761
Ref: Pending Removal in Python 3 14-Footnote-5346816
Ref: Pending Removal in Python 3 14-Footnote-6346872
Ref: Pending Removal in Python 3 14-Footnote-7346928
Ref: Pending Removal in Python 3 14-Footnote-8346983
Ref: Pending Removal in Python 3 14-Footnote-9347038
Ref: Pending Removal in Python 3 14-Footnote-10347094
Ref: Pending Removal in Python 3 14-Footnote-11347150
Ref: Pending Removal in Python 3 14-Footnote-12347206
Node: Pending Removal in Python 3 15347262
Ref: whatsnew/3 13 pending-removal-in-python-3-15347423
Ref: 2d4347423
Ref: Pending Removal in Python 3 15-Footnote-1351751
Ref: Pending Removal in Python 3 15-Footnote-2351806
Ref: Pending Removal in Python 3 15-Footnote-3351861
Ref: Pending Removal in Python 3 15-Footnote-4351916
Ref: Pending Removal in Python 3 15-Footnote-5351972
Ref: Pending Removal in Python 3 15-Footnote-6352014
Node: Pending removal in Python 3 16352070
Ref: whatsnew/3 13 pending-removal-in-python-3-16352231
Ref: 2e1352231
Ref: Pending removal in Python 3 16-Footnote-1354416
Node: Pending removal in Python 3 17354472
Ref: whatsnew/3 13 pending-removal-in-python-3-17354633
Ref: 2e6354633
Ref: Pending removal in Python 3 17-Footnote-1357567
Ref: Pending removal in Python 3 17-Footnote-2357625
Ref: Pending removal in Python 3 17-Footnote-3357680
Ref: Pending removal in Python 3 17-Footnote-4357738
Node: Pending removal in Python 3 18357793
Ref: whatsnew/3 13 pending-removal-in-python-3-18357958
Ref: 2ef357958
Ref: Pending removal in Python 3 18-Footnote-1358386
Node: Pending Removal in Future Versions358441
Ref: whatsnew/3 13 pending-removal-in-future-versions358567
Ref: 2f0358567
Ref: Pending Removal in Future Versions-Footnote-1365361
Ref: Pending Removal in Future Versions-Footnote-2365416
Ref: Pending Removal in Future Versions-Footnote-3365472
Ref: Pending Removal in Future Versions-Footnote-4365528
Ref: Pending Removal in Future Versions-Footnote-5365583
Node: CPython Bytecode Changes365638
Ref: whatsnew/3 13 cpython-bytecode-changes365773
Ref: 313365773
Ref: CPython Bytecode Changes-Footnote-1366214
Node: C API Changes366270
Ref: whatsnew/3 13 c-api-changes366402
Ref: 316366402
Node: New Features<2>366574
Ref: whatsnew/3 13 id7366662
Ref: 317366662
Ref: New Features<2>-Footnote-1377590
Ref: New Features<2>-Footnote-2377632
Ref: New Features<2>-Footnote-3377688
Ref: New Features<2>-Footnote-4377744
Ref: New Features<2>-Footnote-5377800
Ref: New Features<2>-Footnote-6377856
Ref: New Features<2>-Footnote-7377912
Ref: New Features<2>-Footnote-8377968
Ref: New Features<2>-Footnote-9378024
Ref: New Features<2>-Footnote-10378080
Ref: New Features<2>-Footnote-11378137
Ref: New Features<2>-Footnote-12378194
Ref: New Features<2>-Footnote-13378250
Ref: New Features<2>-Footnote-14378307
Ref: New Features<2>-Footnote-15378364
Ref: New Features<2>-Footnote-16378421
Ref: New Features<2>-Footnote-17378478
Ref: New Features<2>-Footnote-18378535
Ref: New Features<2>-Footnote-19378592
Ref: New Features<2>-Footnote-20378649
Ref: New Features<2>-Footnote-21378705
Ref: New Features<2>-Footnote-22378762
Ref: New Features<2>-Footnote-23378819
Ref: New Features<2>-Footnote-24378873
Ref: New Features<2>-Footnote-25378930
Ref: New Features<2>-Footnote-26378986
Ref: New Features<2>-Footnote-27379042
Ref: New Features<2>-Footnote-28379099
Ref: New Features<2>-Footnote-29379156
Ref: New Features<2>-Footnote-30379213
Ref: New Features<2>-Footnote-31379270
Ref: New Features<2>-Footnote-32379327
Node: Changed C APIs379384
Ref: whatsnew/3 13 changed-c-apis379502
Ref: 385379502
Ref: Changed C APIs-Footnote-1382097
Ref: Changed C APIs-Footnote-2382152
Ref: Changed C APIs-Footnote-3382208
Ref: Changed C APIs-Footnote-4382264
Ref: Changed C APIs-Footnote-5382320
Ref: Changed C APIs-Footnote-6382362
Ref: Changed C APIs-Footnote-7382418
Ref: Changed C APIs-Footnote-8382474
Node: Limited C API Changes382530
Ref: whatsnew/3 13 limited-c-api-changes382647
Ref: 392382647
Ref: Limited C API Changes-Footnote-1383350
Ref: Limited C API Changes-Footnote-2383405
Ref: Limited C API Changes-Footnote-3383461
Node: Removed C APIs383517
Ref: whatsnew/3 13 removed-c-apis383637
Ref: 39a383637
Ref: Removed C APIs-Footnote-1389953
Ref: Removed C APIs-Footnote-2390009
Ref: Removed C APIs-Footnote-3390064
Ref: Removed C APIs-Footnote-4390120
Ref: Removed C APIs-Footnote-5390162
Ref: Removed C APIs-Footnote-6390218
Ref: Removed C APIs-Footnote-7390274
Ref: Removed C APIs-Footnote-8390330
Ref: Removed C APIs-Footnote-9390383
Ref: Removed C APIs-Footnote-10390439
Ref: Removed C APIs-Footnote-11390482
Ref: Removed C APIs-Footnote-12390539
Ref: Removed C APIs-Footnote-13390596
Ref: Removed C APIs-Footnote-14390653
Node: Deprecated C APIs390710
Ref: whatsnew/3 13 deprecated-c-apis390800
Ref: 3b1390800
Ref: Deprecated C APIs-Footnote-1393481
Ref: Deprecated C APIs-Footnote-2393537
Ref: Deprecated C APIs-Footnote-3393579
Ref: Deprecated C APIs-Footnote-4393635
Ref: Deprecated C APIs-Footnote-5393690
Ref: Deprecated C APIs-Footnote-6393746
Ref: Deprecated C APIs-Footnote-7393799
Node: Pending Removal in Python 3 14<2>393855
Ref: whatsnew/3 13 id8393984
Ref: 3c3393984
Ref: Pending Removal in Python 3 14<2>-Footnote-1397211
Ref: Pending Removal in Python 3 14<2>-Footnote-2397253
Ref: Pending Removal in Python 3 14<2>-Footnote-3397309
Node: Pending Removal in Python 3 15<2>397364
Ref: whatsnew/3 13 id9397535
Ref: 3ef397535
Node: Pending removal in Python 3 16<2>398788
Ref: whatsnew/3 13 id10398963
Ref: 3f3398963
Node: Pending Removal in Future Versions<2>399086
Ref: whatsnew/3 13 id11399219
Ref: 3f4399219
Node: Build Changes401460
Ref: whatsnew/3 13 build-changes401590
Ref: 412401590
Ref: whatsnew/3 13 pythoncapi-compat-project401590
Ref: 413401590
Ref: Build Changes-Footnote-1404168
Ref: Build Changes-Footnote-2404210
Ref: Build Changes-Footnote-3404266
Ref: Build Changes-Footnote-4404308
Ref: Build Changes-Footnote-5404364
Ref: Build Changes-Footnote-6404406
Ref: Build Changes-Footnote-7404462
Ref: Build Changes-Footnote-8404504
Ref: Build Changes-Footnote-9404560
Ref: Build Changes-Footnote-10404615
Ref: Build Changes-Footnote-11404672
Ref: Build Changes-Footnote-12404729
Ref: Build Changes-Footnote-13404777
Ref: Build Changes-Footnote-14404834
Ref: Build Changes-Footnote-15404891
Ref: Build Changes-Footnote-16404948
Node: Porting to Python 3 13405004
Ref: whatsnew/3 13 porting-to-python-3-13405144
Ref: 146405144
Node: Changes in the Python API405377
Ref: whatsnew/3 13 changes-in-the-python-api405490
Ref: 416405490
Ref: whatsnew/3 13 pep667-porting-notes-py405561
Ref: 183405561
Ref: Changes in the Python API-Footnote-1409108
Ref: Changes in the Python API-Footnote-2409150
Ref: Changes in the Python API-Footnote-3409192
Ref: Changes in the Python API-Footnote-4409234
Ref: Changes in the Python API-Footnote-5409276
Ref: Changes in the Python API-Footnote-6409332
Ref: Changes in the Python API-Footnote-7409388
Ref: Changes in the Python API-Footnote-8409443
Node: Changes in the C API409499
Ref: whatsnew/3 13 changes-in-the-c-api409612
Ref: 420409612
Ref: whatsnew/3 13 pep667-porting-notes-c412267
Ref: 184412267
Ref: Changes in the C API-Footnote-1416021
Ref: Changes in the C API-Footnote-2416077
Ref: Changes in the C API-Footnote-3416133
Ref: Changes in the C API-Footnote-4416189
Ref: Changes in the C API-Footnote-5416244
Ref: Changes in the C API-Footnote-6416300
Node: Regression Test Changes416353
Ref: whatsnew/3 13 regression-test-changes416505
Ref: 426416505
Ref: Regression Test Changes-Footnote-1416946
Node: Notable changes in 3 13 1417002
Ref: whatsnew/3 13 notable-changes-in-3-13-1417157
Ref: 428417157
Node: sys<2>417249
Ref: whatsnew/3 13 id12417317
Ref: 429417317
Node: Notable changes in 3 13 4417568
Ref: whatsnew/3 13 notable-changes-in-3-13-4417691
Ref: 42b417691
Node: os path<2>417803
Ref: whatsnew/3 13 id13417891
Ref: 42c417891
Ref: os path<2>-Footnote-1418298
Node: tarfile418353
Ref: whatsnew/3 13 tarfile418441
Ref: 42f418441
Ref: tarfile-Footnote-1419543
Ref: tarfile-Footnote-2419599
Ref: tarfile-Footnote-3419654
Ref: tarfile-Footnote-4419710
Ref: tarfile-Footnote-5419766
Ref: tarfile-Footnote-6419821
Ref: tarfile-Footnote-7419877
Ref: tarfile-Footnote-8419933
Node: What’s New In Python 3 12419988
Ref: whatsnew/3 12 doc420146
Ref: 435420146
Ref: whatsnew/3 12 translation-repo420146
Ref: 436420146
Ref: whatsnew/3 12 what-s-new-in-python-3-12420146
Ref: 437420146
Ref: What’s New In Python 3 12-Footnote-1420972
Node: Summary – Release highlights421014
Ref: whatsnew/3 12 summary-release-highlights421132
Ref: 438421132
Ref: whatsnew/3 12 improved-error-messages422952
Ref: 441422952
Ref: whatsnew/3 12 unittest-testcase-removed-aliases425773
Ref: 452425773
Ref: Summary – Release highlights-Footnote-1425812
Ref: Summary – Release highlights-Footnote-2425860
Ref: Summary – Release highlights-Footnote-3425902
Ref: Summary – Release highlights-Footnote-4425944
Ref: Summary – Release highlights-Footnote-5426003
Ref: Summary – Release highlights-Footnote-6426082
Node: New Features<3>426137
Ref: whatsnew/3 12 new-features426298
Ref: 453426298
Node: PEP 695 Type Parameter Syntax426873
Ref: whatsnew/3 12 pep-695-type-parameter-syntax427007
Ref: 454427007
Ref: whatsnew/3 12 whatsnew312-pep695427007
Ref: 43a427007
Ref: PEP 695 Type Parameter Syntax-Footnote-1429540
Ref: PEP 695 Type Parameter Syntax-Footnote-2429582
Ref: PEP 695 Type Parameter Syntax-Footnote-3429624
Ref: PEP 695 Type Parameter Syntax-Footnote-4429666
Node: PEP 701 Syntactic formalization of f-strings429722
Ref: whatsnew/3 12 pep-701-syntactic-formalization-of-f-strings429894
Ref: 45c429894
Ref: whatsnew/3 12 whatsnew312-pep701429894
Ref: 43e429894
Ref: PEP 701 Syntactic formalization of f-strings-Footnote-1434196
Ref: PEP 701 Syntactic formalization of f-strings-Footnote-2434238
Ref: PEP 701 Syntactic formalization of f-strings-Footnote-3434280
Ref: PEP 701 Syntactic formalization of f-strings-Footnote-4434322
Node: PEP 684 A Per-Interpreter GIL434378
Ref: whatsnew/3 12 pep-684-a-per-interpreter-gil434562
Ref: 45e434562
Ref: whatsnew/3 12 whatsnew312-pep684434562
Ref: 43f434562
Ref: PEP 684 A Per-Interpreter GIL-Footnote-1435657
Ref: PEP 684 A Per-Interpreter GIL-Footnote-2435699
Ref: PEP 684 A Per-Interpreter GIL-Footnote-3435741
Node: PEP 669 Low impact monitoring for CPython435797
Ref: whatsnew/3 12 pep-669-low-impact-monitoring-for-cpython435992
Ref: 460435992
Ref: whatsnew/3 12 whatsnew312-pep669435992
Ref: 440435992
Ref: PEP 669 Low impact monitoring for CPython-Footnote-1436546
Ref: PEP 669 Low impact monitoring for CPython-Footnote-2436588
Node: PEP 688 Making the buffer protocol accessible in Python436644
Ref: whatsnew/3 12 pep-688-making-the-buffer-protocol-accessible-in-python436840
Ref: 461436840
Ref: whatsnew/3 12 whatsnew312-pep688436840
Ref: 443436840
Ref: PEP 688 Making the buffer protocol accessible in Python-Footnote-1437483
Ref: PEP 688 Making the buffer protocol accessible in Python-Footnote-2437525
Node: PEP 709 Comprehension inlining437581
Ref: whatsnew/3 12 pep-709-comprehension-inlining437759
Ref: 464437759
Ref: whatsnew/3 12 whatsnew312-pep709437759
Ref: 44a437759
Ref: PEP 709 Comprehension inlining-Footnote-1439450
Ref: PEP 709 Comprehension inlining-Footnote-2439492
Node: Improved Error Messages439534
Ref: Improved Error Messages-Footnote-1442001
Ref: Improved Error Messages-Footnote-2442056
Ref: Improved Error Messages-Footnote-3442111
Ref: Improved Error Messages-Footnote-4442166
Node: New Features Related to Type Hints442221
Ref: whatsnew/3 12 new-features-related-to-type-hints442377
Ref: 465442377
Ref: New Features Related to Type Hints-Footnote-1442814
Node: PEP 692 Using TypedDict for more precise **kwargs typing442856
Ref: whatsnew/3 12 pep-692-using-typeddict-for-more-precise-kwargs-typing443036
Ref: 466443036
Ref: whatsnew/3 12 whatsnew312-pep692443036
Ref: 44b443036
Ref: PEP 692 Using TypedDict for more precise **kwargs typing-Footnote-1443730
Ref: PEP 692 Using TypedDict for more precise **kwargs typing-Footnote-2443772
Ref: PEP 692 Using TypedDict for more precise **kwargs typing-Footnote-3443814
Ref: PEP 692 Using TypedDict for more precise **kwargs typing-Footnote-4443856
Node: PEP 698 Override Decorator for Static Typing443912
Ref: whatsnew/3 12 pep-698-override-decorator-for-static-typing444092
Ref: 467444092
Ref: whatsnew/3 12 whatsnew312-pep698444092
Ref: 44d444092
Ref: PEP 698 Override Decorator for Static Typing-Footnote-1445070
Ref: PEP 698 Override Decorator for Static Typing-Footnote-2445112
Node: Other Language Changes<2>445168
Ref: whatsnew/3 12 other-language-changes445323
Ref: 468445323
Ref: Other Language Changes<2>-Footnote-1449994
Ref: Other Language Changes<2>-Footnote-2450049
Ref: Other Language Changes<2>-Footnote-3450104
Ref: Other Language Changes<2>-Footnote-4450159
Ref: Other Language Changes<2>-Footnote-5450201
Ref: Other Language Changes<2>-Footnote-6450257
Ref: Other Language Changes<2>-Footnote-7450299
Ref: Other Language Changes<2>-Footnote-8450354
Ref: Other Language Changes<2>-Footnote-9450410
Ref: Other Language Changes<2>-Footnote-10450465
Ref: Other Language Changes<2>-Footnote-11450521
Ref: Other Language Changes<2>-Footnote-12450577
Ref: Other Language Changes<2>-Footnote-13450634
Ref: Other Language Changes<2>-Footnote-14450691
Ref: Other Language Changes<2>-Footnote-15450747
Ref: Other Language Changes<2>-Footnote-16450790
Ref: Other Language Changes<2>-Footnote-17450846
Node: New Modules<2>450902
Ref: whatsnew/3 12 new-modules451042
Ref: 475451042
Node: Improved Modules<2>451091
Ref: whatsnew/3 12 improved-modules451222
Ref: 476451222
Node: array<2>451860
Ref: whatsnew/3 12 array451943
Ref: 477451943
Ref: array<2>-Footnote-1452171
Node: asyncio<2>452226
Ref: whatsnew/3 12 asyncio452326
Ref: 478452326
Ref: asyncio<2>-Footnote-1454311
Ref: asyncio<2>-Footnote-2454366
Ref: asyncio<2>-Footnote-3454422
Ref: asyncio<2>-Footnote-4454478
Ref: asyncio<2>-Footnote-5454534
Ref: asyncio<2>-Footnote-6454589
Ref: asyncio<2>-Footnote-7454644
Ref: asyncio<2>-Footnote-8454699
Ref: asyncio<2>-Footnote-9454755
Ref: asyncio<2>-Footnote-10454811
Node: calendar454867
Ref: whatsnew/3 12 calendar454962
Ref: 483454962
Ref: calendar-Footnote-1455214
Node: csv455270
Ref: whatsnew/3 12 csv455361
Ref: 486455361
Node: dis<2>455595
Ref: whatsnew/3 12 dis455690
Ref: 48b455690
Ref: dis<2>-Footnote-1456300
Ref: dis<2>-Footnote-2456355
Node: fractions<2>456410
Ref: whatsnew/3 12 fractions456521
Ref: 48e456521
Ref: fractions<2>-Footnote-1456743
Node: importlib resources456799
Ref: whatsnew/3 12 importlib-resources456911
Ref: 48f456911
Ref: importlib resources-Footnote-1457283
Ref: importlib resources-Footnote-2457338
Node: inspect457394
Ref: whatsnew/3 12 inspect457506
Ref: 492457506
Ref: inspect-Footnote-1458276
Ref: inspect-Footnote-2458331
Ref: inspect-Footnote-3458386
Node: itertools<2>458442
Ref: whatsnew/3 12 itertools458542
Ref: 498458542
Ref: itertools<2>-Footnote-1458807
Node: math<2>458862
Ref: whatsnew/3 12 math458960
Ref: 499458960
Ref: math<2>-Footnote-1459378
Ref: math<2>-Footnote-2459434
Node: os<2>459489
Ref: whatsnew/3 12 os459585
Ref: 49c459585
Ref: os<2>-Footnote-1460930
Ref: os<2>-Footnote-2460985
Ref: os<2>-Footnote-3461040
Ref: os<2>-Footnote-4461096
Node: os path<3>461151
Ref: whatsnew/3 12 os-path461250
Ref: 4a5461250
Ref: os path<3>-Footnote-1461615
Ref: os path<3>-Footnote-2461670
Node: pathlib<3>461726
Ref: whatsnew/3 12 pathlib461828
Ref: 4a8461828
Ref: pathlib<3>-Footnote-1463125
Ref: pathlib<3>-Footnote-2463180
Ref: pathlib<3>-Footnote-3463235
Node: platform463290
Ref: whatsnew/3 12 platform463388
Ref: 4b0463388
Ref: platform-Footnote-1463733
Node: pdb<2>463788
Ref: whatsnew/3 12 pdb463885
Ref: 4b1463885
Ref: pdb<2>-Footnote-1464158
Node: random<2>464214
Ref: whatsnew/3 12 random464312
Ref: 4b2464312
Ref: random<2>-Footnote-1464617
Ref: random<2>-Footnote-2464672
Node: shutil<2>464728
Ref: whatsnew/3 12 shutil464830
Ref: 4b5464830
Ref: shutil<2>-Footnote-1466260
Ref: shutil<2>-Footnote-2466315
Ref: shutil<2>-Footnote-3466371
Ref: shutil<2>-Footnote-4466427
Ref: shutil<2>-Footnote-5466483
Node: sqlite3<2>466539
Ref: whatsnew/3 12 sqlite3466645
Ref: 4b8466645
Ref: sqlite3<2>-Footnote-1467592
Ref: sqlite3<2>-Footnote-2467647
Ref: sqlite3<2>-Footnote-3467689
Ref: sqlite3<2>-Footnote-4467744
Ref: sqlite3<2>-Footnote-5467800
Node: statistics<2>467856
Ref: whatsnew/3 12 statistics467959
Ref: 4be467959
Ref: statistics<2>-Footnote-1468239
Node: sys<3>468294
Ref: whatsnew/3 12 sys468398
Ref: 4c0468398
Ref: sys<3>-Footnote-1469948
Ref: sys<3>-Footnote-2470004
Ref: sys<3>-Footnote-3470059
Ref: sys<3>-Footnote-4470115
Node: tempfile<2>470171
Ref: whatsnew/3 12 tempfile470271
Ref: 4c8470271
Ref: tempfile<2>-Footnote-1470663
Node: threading470718
Ref: whatsnew/3 12 threading470822
Ref: 4ca470822
Ref: threading-Footnote-1471171
Node: tkinter<2>471226
Ref: whatsnew/3 12 tkinter471327
Ref: 4cd471327
Ref: tkinter<2>-Footnote-1471823
Node: tokenize471878
Ref: whatsnew/3 12 tokenize471978
Ref: 4ce471978
Ref: tokenize-Footnote-1472330
Ref: tokenize-Footnote-2472372
Node: types<2>472428
Ref: whatsnew/3 12 types472527
Ref: 4d0472527
Ref: types<2>-Footnote-1472823
Node: typing<3>472879
Ref: whatsnew/3 12 typing472984
Ref: 4d3472984
Ref: whatsnew/3 12 whatsnew-typing-py312472984
Ref: 4d4472984
Ref: typing<3>-Footnote-1475559
Ref: typing<3>-Footnote-2475615
Ref: typing<3>-Footnote-3475670
Ref: typing<3>-Footnote-4475726
Ref: typing<3>-Footnote-5475782
Node: unicodedata<2>475837
Ref: whatsnew/3 12 unicodedata475945
Ref: 4d8475945
Ref: unicodedata<2>-Footnote-1476143
Node: unittest<2>476198
Ref: whatsnew/3 12 unittest476301
Ref: 4d9476301
Ref: unittest<2>-Footnote-1477085
Node: uuid477140
Ref: whatsnew/3 12 uuid477220
Ref: 4da477220
Ref: uuid-Footnote-1477383
Node: Optimizations<2>477438
Ref: whatsnew/3 12 optimizations477579
Ref: 4db477579
Ref: Optimizations<2>-Footnote-1479032
Ref: Optimizations<2>-Footnote-2479074
Ref: Optimizations<2>-Footnote-3479129
Ref: Optimizations<2>-Footnote-4479184
Ref: Optimizations<2>-Footnote-5479240
Ref: Optimizations<2>-Footnote-6479295
Ref: Optimizations<2>-Footnote-7479351
Ref: Optimizations<2>-Footnote-8479393
Ref: Optimizations<2>-Footnote-9479449
Node: CPython bytecode changes479505
Ref: whatsnew/3 12 cpython-bytecode-changes479642
Ref: 4e0479642
Ref: CPython bytecode changes-Footnote-1481666
Ref: CPython bytecode changes-Footnote-2481721
Ref: CPython bytecode changes-Footnote-3481777
Ref: CPython bytecode changes-Footnote-4481832
Ref: CPython bytecode changes-Footnote-5481887
Ref: CPython bytecode changes-Footnote-6481942
Ref: CPython bytecode changes-Footnote-7481998
Ref: CPython bytecode changes-Footnote-8482053
Ref: CPython bytecode changes-Footnote-9482109
Ref: CPython bytecode changes-Footnote-10482151
Ref: CPython bytecode changes-Footnote-11482208
Ref: CPython bytecode changes-Footnote-12482264
Ref: CPython bytecode changes-Footnote-13482307
Ref: CPython bytecode changes-Footnote-14482364
Ref: CPython bytecode changes-Footnote-15482421
Node: Demos and Tools482478
Ref: whatsnew/3 12 demos-and-tools482609
Ref: 4ed482609
Ref: Demos and Tools-Footnote-1483062
Ref: Demos and Tools-Footnote-2483110
Ref: Demos and Tools-Footnote-3483165
Ref: Demos and Tools-Footnote-4483213
Node: Deprecated483268
Ref: whatsnew/3 12 deprecated483382
Ref: 4ee483382
Ref: Deprecated-Footnote-1494612
Ref: Deprecated-Footnote-2494667
Ref: Deprecated-Footnote-3494722
Ref: Deprecated-Footnote-4494777
Ref: Deprecated-Footnote-5494832
Ref: Deprecated-Footnote-6494888
Ref: Deprecated-Footnote-7494944
Ref: Deprecated-Footnote-8495002
Ref: Deprecated-Footnote-9495057
Ref: Deprecated-Footnote-10495113
Ref: Deprecated-Footnote-11495169
Ref: Deprecated-Footnote-12495225
Ref: Deprecated-Footnote-13495282
Ref: Deprecated-Footnote-14495338
Ref: Deprecated-Footnote-15495394
Ref: Deprecated-Footnote-16495450
Ref: Deprecated-Footnote-17495506
Ref: Deprecated-Footnote-18495609
Ref: Deprecated-Footnote-19495666
Ref: Deprecated-Footnote-20495722
Ref: Deprecated-Footnote-21495779
Ref: Deprecated-Footnote-22495836
Ref: Deprecated-Footnote-23495892
Ref: Deprecated-Footnote-24495948
Ref: Deprecated-Footnote-25496004
Ref: Deprecated-Footnote-26496060
Ref: Deprecated-Footnote-27496116
Ref: Deprecated-Footnote-28496172
Ref: Deprecated-Footnote-29496229
Ref: Deprecated-Footnote-30496272
Node: Pending Removal in Python 3 13496329
Ref: whatsnew/3 12 pending-removal-in-python-3-13496448
Ref: 4fe496448
Ref: Pending Removal in Python 3 13-Footnote-1497515
Ref: Pending Removal in Python 3 13-Footnote-2497557
Ref: Pending Removal in Python 3 13-Footnote-3497612
Ref: Pending Removal in Python 3 13-Footnote-4497667
Ref: Pending Removal in Python 3 13-Footnote-5497722
Ref: Pending Removal in Python 3 13-Footnote-6497777
Ref: Pending Removal in Python 3 13-Footnote-7497832
Ref: Pending Removal in Python 3 13-Footnote-8497887
Ref: Pending Removal in Python 3 13-Footnote-9497942
Ref: Pending Removal in Python 3 13-Footnote-10497997
Ref: Pending Removal in Python 3 13-Footnote-11498053
Node: Pending Removal in Python 3 14<3>498109
Ref: whatsnew/3 12 pending-removal-in-python-3-14498270
Ref: 4ff498270
Ref: Pending Removal in Python 3 14<3>-Footnote-1502734
Ref: Pending Removal in Python 3 14<3>-Footnote-2502789
Ref: Pending Removal in Python 3 14<3>-Footnote-3502844
Ref: Pending Removal in Python 3 14<3>-Footnote-4502899
Ref: Pending Removal in Python 3 14<3>-Footnote-5502954
Ref: Pending Removal in Python 3 14<3>-Footnote-6503010
Ref: Pending Removal in Python 3 14<3>-Footnote-7503066
Ref: Pending Removal in Python 3 14<3>-Footnote-8503121
Ref: Pending Removal in Python 3 14<3>-Footnote-9503176
Ref: Pending Removal in Python 3 14<3>-Footnote-10503232
Ref: Pending Removal in Python 3 14<3>-Footnote-11503288
Ref: Pending Removal in Python 3 14<3>-Footnote-12503344
Node: Pending Removal in Python 3 15<3>503400
Ref: whatsnew/3 12 pending-removal-in-python-3-15503564
Ref: 500503564
Ref: Pending Removal in Python 3 15<3>-Footnote-1507894
Ref: Pending Removal in Python 3 15<3>-Footnote-2507949
Ref: Pending Removal in Python 3 15<3>-Footnote-3508004
Ref: Pending Removal in Python 3 15<3>-Footnote-4508059
Ref: Pending Removal in Python 3 15<3>-Footnote-5508115
Ref: Pending Removal in Python 3 15<3>-Footnote-6508157
Node: Pending removal in Python 3 16<3>508213
Ref: whatsnew/3 12 pending-removal-in-python-3-16508377
Ref: 501508377
Ref: Pending removal in Python 3 16<3>-Footnote-1510564
Node: Pending removal in Python 3 17<2>510620
Ref: whatsnew/3 12 pending-removal-in-python-3-17510788
Ref: 502510788
Ref: Pending removal in Python 3 17<2>-Footnote-1513724
Ref: Pending removal in Python 3 17<2>-Footnote-2513782
Ref: Pending removal in Python 3 17<2>-Footnote-3513837
Ref: Pending removal in Python 3 17<2>-Footnote-4513895
Node: Pending Removal in Future Versions<3>513950
Ref: whatsnew/3 12 pending-removal-in-future-versions514076
Ref: 503514076
Ref: Pending Removal in Future Versions<3>-Footnote-1520872
Ref: Pending Removal in Future Versions<3>-Footnote-2520927
Ref: Pending Removal in Future Versions<3>-Footnote-3520983
Ref: Pending Removal in Future Versions<3>-Footnote-4521039
Ref: Pending Removal in Future Versions<3>-Footnote-5521094
Node: Removed521149
Ref: whatsnew/3 12 removed521270
Ref: 504521270
Ref: whatsnew/3 12 whatsnew312-removed521270
Ref: 505521270
Node: asynchat and asyncore521704
Ref: whatsnew/3 12 asynchat-and-asyncore521793
Ref: 506521793
Ref: asynchat and asyncore-Footnote-1522109
Ref: asynchat and asyncore-Footnote-2522151
Node: configparser<3>522206
Ref: whatsnew/3 12 configparser522313
Ref: 507522313
Ref: configparser<3>-Footnote-1522970
Node: distutils523025
Ref: whatsnew/3 12 distutils523120
Ref: 50a523120
Ref: whatsnew/3 12 whatsnew312-removed-distutils523120
Ref: 50b523120
Ref: distutils-Footnote-1523553
Ref: distutils-Footnote-2523595
Node: ensurepip523650
Ref: whatsnew/3 12 ensurepip523737
Ref: 50c523737
Ref: ensurepip-Footnote-1524758
Node: enum<2>524813
Ref: whatsnew/3 12 enum524897
Ref: 50d524897
Ref: enum<2>-Footnote-1525133
Node: ftplib525188
Ref: whatsnew/3 12 ftplib525267
Ref: 50e525267
Ref: ftplib-Footnote-1525510
Node: gzip525565
Ref: whatsnew/3 12 gzip525644
Ref: 50f525644
Ref: gzip-Footnote-1526042
Node: hashlib526097
Ref: whatsnew/3 12 hashlib526182
Ref: 511526182
Ref: hashlib-Footnote-1526603
Ref: hashlib-Footnote-2526645
Node: importlib<2>526700
Ref: whatsnew/3 12 importlib526784
Ref: 513526784
Ref: importlib<2>-Footnote-1527674
Ref: importlib<2>-Footnote-2527729
Ref: importlib<2>-Footnote-3527784
Ref: importlib<2>-Footnote-4527839
Ref: importlib<2>-Footnote-5527894
Node: imp527949
Ref: whatsnew/3 12 imp528031
Ref: 514528031
Ref: whatsnew/3 12 whatsnew312-removed-imp528031
Ref: 515528031
Ref: imp-Footnote-1532147
Node: io<2>532202
Ref: whatsnew/3 12 io532281
Ref: 51e532281
Ref: io<2>-Footnote-1532696
Node: locale<2>532751
Ref: whatsnew/3 12 locale532832
Ref: 521532832
Ref: locale<2>-Footnote-1533102
Node: smtpd533157
Ref: whatsnew/3 12 smtpd533243
Ref: 523533243
Ref: smtpd-Footnote-1533597
Ref: smtpd-Footnote-2533639
Ref: smtpd-Footnote-3533682
Node: sqlite3<3>533737
Ref: whatsnew/3 12 id2533820
Ref: 524533820
Ref: sqlite3<3>-Footnote-1534554
Node: ssl<2>534609
Ref: whatsnew/3 12 ssl534698
Ref: 525534698
Ref: ssl<2>-Footnote-1535757
Ref: ssl<2>-Footnote-2535812
Ref: ssl<2>-Footnote-3535867
Ref: ssl<2>-Footnote-4535923
Node: unittest<3>535978
Ref: whatsnew/3 12 id3536070
Ref: 529536070
Ref: unittest<3>-Footnote-1540835
Node: webbrowser<2>540890
Ref: whatsnew/3 12 webbrowser540997
Ref: 535540997
Ref: webbrowser<2>-Footnote-1541304
Node: xml etree ElementTree541360
Ref: whatsnew/3 12 xml-etree-elementtree541468
Ref: 536541468
Ref: xml etree ElementTree-Footnote-1541931
Node: zipimport<2>541986
Ref: whatsnew/3 12 zipimport542087
Ref: 538542087
Ref: zipimport<2>-Footnote-1542424
Ref: zipimport<2>-Footnote-2542466
Node: Others542521
Ref: whatsnew/3 12 others542592
Ref: 539542592
Ref: Others-Footnote-1543595
Ref: Others-Footnote-2543649
Ref: Others-Footnote-3543704
Ref: Others-Footnote-4543759
Ref: Others-Footnote-5543814
Node: Porting to Python 3 12543869
Ref: whatsnew/3 12 porting-to-python-3-12543996
Ref: 53a543996
Ref: whatsnew/3 12 whatsnew312-porting-to-python312543996
Ref: 4cf543996
Node: Changes in the Python API<2>544233
Ref: whatsnew/3 12 changes-in-the-python-api544320
Ref: 53b544320
Ref: Changes in the Python API<2>-Footnote-1550610
Ref: Changes in the Python API<2>-Footnote-2550665
Ref: Changes in the Python API<2>-Footnote-3550720
Ref: Changes in the Python API<2>-Footnote-4550763
Ref: Changes in the Python API<2>-Footnote-5550818
Ref: Changes in the Python API<2>-Footnote-6550873
Ref: Changes in the Python API<2>-Footnote-7550928
Ref: Changes in the Python API<2>-Footnote-8550984
Ref: Changes in the Python API<2>-Footnote-9551026
Ref: Changes in the Python API<2>-Footnote-10551068
Ref: Changes in the Python API<2>-Footnote-11551111
Node: Build Changes<2>551168
Ref: whatsnew/3 12 build-changes551304
Ref: 547551304
Ref: Build Changes<2>-Footnote-1552989
Ref: Build Changes<2>-Footnote-2553044
Ref: Build Changes<2>-Footnote-3553099
Ref: Build Changes<2>-Footnote-4553154
Ref: Build Changes<2>-Footnote-5553209
Ref: Build Changes<2>-Footnote-6553264
Node: C API Changes<2>553319
Ref: whatsnew/3 12 c-api-changes553424
Ref: 548553424
Node: New Features<4>553615
Ref: whatsnew/3 12 id4553717
Ref: 549553717
Ref: whatsnew/3 12 whatsnew312-pep697553762
Ref: 448553762
Ref: whatsnew/3 12 whatsnew312-pep683559908
Ref: 449559908
Ref: New Features<4>-Footnote-1561636
Ref: New Features<4>-Footnote-2561678
Ref: New Features<4>-Footnote-3561720
Ref: New Features<4>-Footnote-4561776
Ref: New Features<4>-Footnote-5561818
Ref: New Features<4>-Footnote-6561874
Ref: New Features<4>-Footnote-7561929
Ref: New Features<4>-Footnote-8561984
Ref: New Features<4>-Footnote-9562039
Ref: New Features<4>-Footnote-10562094
Ref: New Features<4>-Footnote-11562150
Ref: New Features<4>-Footnote-12562206
Ref: New Features<4>-Footnote-13562262
Ref: New Features<4>-Footnote-14562318
Ref: New Features<4>-Footnote-15562374
Ref: New Features<4>-Footnote-16562431
Ref: New Features<4>-Footnote-17562488
Ref: New Features<4>-Footnote-18562545
Ref: New Features<4>-Footnote-19562602
Ref: New Features<4>-Footnote-20562645
Ref: New Features<4>-Footnote-21562701
Ref: New Features<4>-Footnote-22562744
Ref: New Features<4>-Footnote-23562801
Node: Porting to Python 3 12<2>562858
Ref: whatsnew/3 12 id5562982
Ref: 573562982
Ref: Porting to Python 3 12<2>-Footnote-1570453
Ref: Porting to Python 3 12<2>-Footnote-2570508
Ref: Porting to Python 3 12<2>-Footnote-3570563
Ref: Porting to Python 3 12<2>-Footnote-4570618
Ref: Porting to Python 3 12<2>-Footnote-5570673
Ref: Porting to Python 3 12<2>-Footnote-6570728
Ref: Porting to Python 3 12<2>-Footnote-7570783
Ref: Porting to Python 3 12<2>-Footnote-8570839
Node: Deprecated<2>570895
Ref: whatsnew/3 12 id6571014
Ref: 58f571014
Ref: Deprecated<2>-Footnote-1576422
Ref: Deprecated<2>-Footnote-2576464
Ref: Deprecated<2>-Footnote-3576520
Ref: Deprecated<2>-Footnote-4576575
Ref: Deprecated<2>-Footnote-5576630
Ref: Deprecated<2>-Footnote-6576685
Ref: Deprecated<2>-Footnote-7576741
Ref: Deprecated<2>-Footnote-8576797
Node: Pending Removal in Python 3 14<4>576853
Ref: whatsnew/3 12 id7576978
Ref: 599576978
Ref: Pending Removal in Python 3 14<4>-Footnote-1580205
Ref: Pending Removal in Python 3 14<4>-Footnote-2580247
Ref: Pending Removal in Python 3 14<4>-Footnote-3580303
Node: Pending Removal in Python 3 15<4>580358
Ref: whatsnew/3 12 id8580525
Ref: 59a580525
Node: Pending removal in Python 3 16<4>581778
Ref: whatsnew/3 12 id9581949
Ref: 59b581949
Node: Pending Removal in Future Versions<4>582072
Ref: whatsnew/3 12 id10582201
Ref: 59c582201
Node: Removed<2>584442
Ref: whatsnew/3 12 id11584527
Ref: 59d584527
Ref: Removed<2>-Footnote-1585382
Ref: Removed<2>-Footnote-2585437
Ref: Removed<2>-Footnote-3585479
Node: What’s New In Python 3 11585534
Ref: whatsnew/3 11 doc585692
Ref: 59e585692
Ref: whatsnew/3 11 translation-repo585692
Ref: 59f585692
Ref: whatsnew/3 11 what-s-new-in-python-3-11585692
Ref: 5a0585692
Node: Summary – Release highlights<2>586772
Ref: whatsnew/3 11 summary-release-highlights586893
Ref: 5a1586893
Ref: whatsnew/3 11 whatsnew311-summary586893
Ref: 5a2586893
Ref: Summary – Release highlights<2>-Footnote-1588420
Ref: Summary – Release highlights<2>-Footnote-2588462
Ref: Summary – Release highlights<2>-Footnote-3588487
Ref: Summary – Release highlights<2>-Footnote-4588529
Ref: Summary – Release highlights<2>-Footnote-5588571
Node: New Features<5>588613
Ref: whatsnew/3 11 new-features588780
Ref: 5b2588780
Ref: whatsnew/3 11 whatsnew311-features588780
Ref: 5b3588780
Node: PEP 657 Fine-grained error locations in tracebacks589190
Ref: whatsnew/3 11 pep-657-fine-grained-error-locations-in-tracebacks589337
Ref: 5b4589337
Ref: whatsnew/3 11 whatsnew311-pep657589337
Ref: 5a6589337
Ref: PEP 657 Fine-grained error locations in tracebacks-Footnote-1592108
Ref: PEP 657 Fine-grained error locations in tracebacks-Footnote-2592150
Node: PEP 654 Exception Groups and except*592215
Ref: whatsnew/3 11 pep-654-exception-groups-and-except592416
Ref: 5ba592416
Ref: whatsnew/3 11 whatsnew311-pep654592416
Ref: 5a4592416
Ref: PEP 654 Exception Groups and except*-Footnote-1593084
Ref: PEP 654 Exception Groups and except*-Footnote-2593126
Ref: PEP 654 Exception Groups and except*-Footnote-3593168
Node: PEP 678 Exceptions can be enriched with notes593233
Ref: whatsnew/3 11 pep-678-exceptions-can-be-enriched-with-notes593420
Ref: 5bc593420
Ref: whatsnew/3 11 whatsnew311-pep678593420
Ref: 5a5593420
Ref: PEP 678 Exceptions can be enriched with notes-Footnote-1593933
Ref: PEP 678 Exceptions can be enriched with notes-Footnote-2593975
Node: Windows py exe launcher improvements594040
Ref: whatsnew/3 11 whatsnew311-windows-launcher594182
Ref: 5bf594182
Ref: whatsnew/3 11 windows-py-exe-launcher-improvements594182
Ref: 5c0594182
Ref: whatsnew/3 11 new-feat-related-type-hints-311595506
Ref: 5c2595506
Ref: Windows py exe launcher improvements-Footnote-1595544
Ref: Windows py exe launcher improvements-Footnote-2595586
Node: New Features Related to Type Hints<2>595617
Ref: whatsnew/3 11 new-features-related-to-type-hints595776
Ref: 5c3595776
Ref: whatsnew/3 11 whatsnew311-typing-features595776
Ref: 5c4595776
Ref: New Features Related to Type Hints<2>-Footnote-1596432
Node: PEP 646 Variadic generics596474
Ref: whatsnew/3 11 pep-646-variadic-generics596652
Ref: 5c5596652
Ref: whatsnew/3 11 whatsnew311-pep646596652
Ref: 5aa596652
Ref: PEP 646 Variadic generics-Footnote-1597624
Ref: PEP 646 Variadic generics-Footnote-2597666
Ref: PEP 646 Variadic generics-Footnote-3597708
Ref: PEP 646 Variadic generics-Footnote-4597750
Node: PEP 655 Marking individual TypedDict items as required or not-required597815
Ref: whatsnew/3 11 pep-655-marking-individual-typeddict-items-as-required-or-not-required598019
Ref: 5c6598019
Ref: whatsnew/3 11 whatsnew311-pep655598019
Ref: 5ab598019
Ref: PEP 655 Marking individual TypedDict items as required or not-required-Footnote-1599239
Ref: PEP 655 Marking individual TypedDict items as required or not-required-Footnote-2599281
Node: PEP 673 Self type599346
Ref: whatsnew/3 11 pep-673-self-type599562
Ref: 5c9599562
Ref: whatsnew/3 11 whatsnew311-pep673599562
Ref: 5ac599562
Ref: PEP 673 Self type-Footnote-1600606
Ref: PEP 673 Self type-Footnote-2600687
Ref: PEP 673 Self type-Footnote-3600729
Node: PEP 675 Arbitrary literal string type600794
Ref: whatsnew/3 11 pep-675-arbitrary-literal-string-type600969
Ref: 5cc600969
Ref: whatsnew/3 11 whatsnew311-pep675600969
Ref: 5ad600969
Ref: PEP 675 Arbitrary literal string type-Footnote-1602363
Ref: PEP 675 Arbitrary literal string type-Footnote-2602405
Node: PEP 681 Data class transforms602470
Ref: whatsnew/3 11 pep-681-data-class-transforms602657
Ref: 5ce602657
Ref: whatsnew/3 11 whatsnew311-pep681602657
Ref: 5ae602657
Ref: PEP 681 Data class transforms-Footnote-1603690
Ref: PEP 681 Data class transforms-Footnote-2603732
Node: PEP 563 may not be the future603787
Ref: whatsnew/3 11 pep-563-may-not-be-the-future603928
Ref: 5cf603928
Ref: whatsnew/3 11 whatsnew311-pep563-deferred603928
Ref: 5d0603928
Ref: PEP 563 may not be the future-Footnote-1604323
Ref: PEP 563 may not be the future-Footnote-2604365
Node: Other Language Changes<3>604476
Ref: whatsnew/3 11 other-language-changes604656
Ref: 5d1604656
Ref: whatsnew/3 11 whatsnew311-other-lang-changes604656
Ref: 5d2604656
Ref: whatsnew/3 11 whatsnew311-pythonsafepath606459
Ref: 5a9606459
Ref: Other Language Changes<3>-Footnote-1607807
Ref: Other Language Changes<3>-Footnote-2607872
Ref: Other Language Changes<3>-Footnote-3607937
Ref: Other Language Changes<3>-Footnote-4608002
Ref: Other Language Changes<3>-Footnote-5608067
Ref: Other Language Changes<3>-Footnote-6608122
Ref: Other Language Changes<3>-Footnote-7608187
Ref: Other Language Changes<3>-Footnote-8608242
Ref: Other Language Changes<3>-Footnote-9608284
Ref: Other Language Changes<3>-Footnote-10608339
Node: Other CPython Implementation Changes608395
Ref: whatsnew/3 11 other-cpython-implementation-changes608552
Ref: 5e8608552
Ref: whatsnew/3 11 whatsnew311-other-implementation-changes608552
Ref: 5e9608552
Ref: Other CPython Implementation Changes-Footnote-1611806
Ref: Other CPython Implementation Changes-Footnote-2611871
Ref: Other CPython Implementation Changes-Footnote-3611913
Ref: Other CPython Implementation Changes-Footnote-4611978
Ref: Other CPython Implementation Changes-Footnote-5612043
Ref: Other CPython Implementation Changes-Footnote-6612108
Ref: Other CPython Implementation Changes-Footnote-7612173
Ref: Other CPython Implementation Changes-Footnote-8612238
Node: New Modules<3>612294
Ref: whatsnew/3 11 new-modules612445
Ref: 5f9612445
Ref: whatsnew/3 11 whatsnew311-new-modules612445
Ref: 5fa612445
Ref: New Modules<3>-Footnote-1612793
Ref: New Modules<3>-Footnote-2612818
Ref: New Modules<3>-Footnote-3612860
Ref: New Modules<3>-Footnote-4612925
Ref: New Modules<3>-Footnote-5612967
Node: Improved Modules<3>613032
Ref: whatsnew/3 11 improved-modules613163
Ref: 5fb613163
Ref: whatsnew/3 11 whatsnew311-improved-modules613163
Ref: 5fc613163
Node: asyncio<3>613896
Ref: whatsnew/3 11 asyncio613981
Ref: 5fd613981
Ref: whatsnew/3 11 whatsnew311-asyncio613981
Ref: 5fe613981
Ref: asyncio<3>-Footnote-1615899
Ref: asyncio<3>-Footnote-2615954
Ref: asyncio<3>-Footnote-3616009
Ref: asyncio<3>-Footnote-4616064
Ref: asyncio<3>-Footnote-5616119
Ref: asyncio<3>-Footnote-6616184
Node: contextlib616249
Ref: whatsnew/3 11 contextlib616354
Ref: 60d616354
Ref: whatsnew/3 11 whatsnew311-contextlib616354
Ref: 60e616354
Ref: contextlib-Footnote-1616669
Node: dataclasses616734
Ref: whatsnew/3 11 dataclasses616837
Ref: 611616837
Ref: whatsnew/3 11 whatsnew311-dataclasses616837
Ref: 612616837
Ref: dataclasses-Footnote-1617179
Node: datetime617244
Ref: whatsnew/3 11 datetime617344
Ref: 615617344
Ref: whatsnew/3 11 whatsnew311-datetime617344
Ref: 616617344
Ref: datetime-Footnote-1617883
Ref: datetime-Footnote-2617938
Node: enum<3>617993
Ref: whatsnew/3 11 enum618087
Ref: 61b618087
Ref: whatsnew/3 11 whatsnew311-enum618087
Ref: 61c618087
Node: fcntl620733
Ref: whatsnew/3 11 fcntl620831
Ref: 636620831
Ref: whatsnew/3 11 whatsnew311-fcntl620831
Ref: 637620831
Node: fractions<3>621066
Ref: whatsnew/3 11 fractions621166
Ref: 638621166
Ref: whatsnew/3 11 whatsnew311-fractions621166
Ref: 639621166
Ref: fractions<3>-Footnote-1621584
Ref: fractions<3>-Footnote-2621626
Ref: fractions<3>-Footnote-3621691
Node: functools621756
Ref: whatsnew/3 11 functools621858
Ref: 63a621858
Ref: whatsnew/3 11 whatsnew311-functools621858
Ref: 63b621858
Ref: functools-Footnote-1622930
Node: gzip<2>622995
Ref: whatsnew/3 11 gzip623095
Ref: 63f623095
Ref: whatsnew/3 11 whatsnew311-gzip623095
Ref: 640623095
Ref: gzip<2>-Footnote-1623800
Node: hashlib<2>623856
Ref: whatsnew/3 11 hashlib623963
Ref: 643623963
Ref: whatsnew/3 11 whatsnew311-hashlib623963
Ref: 644623963
Ref: hashlib<2>-Footnote-1624786
Ref: hashlib<2>-Footnote-2624818
Ref: hashlib<2>-Footnote-3624883
Ref: hashlib<2>-Footnote-4624948
Node: IDLE and idlelib625003
Ref: whatsnew/3 11 idle-and-idlelib625113
Ref: 648625113
Ref: whatsnew/3 11 whatsnew311-idle625113
Ref: 649625113
Ref: IDLE and idlelib-Footnote-1625447
Ref: IDLE and idlelib-Footnote-2625512
Node: inspect<2>625567
Ref: whatsnew/3 11 inspect625676
Ref: 64a625676
Ref: whatsnew/3 11 whatsnew311-inspect625676
Ref: 64b625676
Ref: inspect<2>-Footnote-1626763
Ref: inspect<2>-Footnote-2626828
Ref: inspect<2>-Footnote-3626893
Ref: inspect<2>-Footnote-4626935
Node: locale<3>626990
Ref: whatsnew/3 11 locale627090
Ref: 657627090
Ref: whatsnew/3 11 whatsnew311-locale627090
Ref: 658627090
Node: logging627317
Ref: whatsnew/3 11 logging627414
Ref: 65a627414
Ref: whatsnew/3 11 whatsnew311-logging627414
Ref: 65b627414
Ref: logging-Footnote-1628073
Ref: logging-Footnote-2628128
Node: math<3>628183
Ref: whatsnew/3 11 math628279
Ref: 661628279
Ref: whatsnew/3 11 whatsnew311-math628279
Ref: 662628279
Ref: math<3>-Footnote-1629052
Ref: math<3>-Footnote-2629117
Ref: math<3>-Footnote-3629182
Ref: math<3>-Footnote-4629247
Node: operator629312
Ref: whatsnew/3 11 operator629406
Ref: 667629406
Ref: whatsnew/3 11 whatsnew311-operator629406
Ref: 668629406
Ref: operator-Footnote-1629668
Node: os<3>629733
Ref: whatsnew/3 11 os629830
Ref: 669629830
Ref: whatsnew/3 11 whatsnew311-os629830
Ref: 66a629830
Ref: os<3>-Footnote-1630079
Node: pathlib<4>630144
Ref: whatsnew/3 11 pathlib630238
Ref: 66b630238
Ref: whatsnew/3 11 whatsnew311-pathlib630238
Ref: 66c630238
Ref: pathlib<4>-Footnote-1630559
Ref: pathlib<4>-Footnote-2630624
Node: re<3>630689
Ref: whatsnew/3 11 re630787
Ref: 66f630787
Ref: whatsnew/3 11 whatsnew311-re630787
Ref: 670630787
Ref: re<3>-Footnote-1631089
Node: shutil<3>631155
Ref: whatsnew/3 11 shutil631249
Ref: 671631249
Ref: whatsnew/3 11 whatsnew311-shutil631249
Ref: 672631249
Ref: shutil<3>-Footnote-1631443
Node: socket631508
Ref: whatsnew/3 11 socket631607
Ref: 673631607
Ref: whatsnew/3 11 whatsnew311-socket631607
Ref: 674631607
Ref: socket-Footnote-1632020
Ref: socket-Footnote-2632085
Node: sqlite3<4>632150
Ref: whatsnew/3 11 sqlite3632246
Ref: 676632246
Ref: whatsnew/3 11 whatsnew311-sqlite3632246
Ref: 677632246
Ref: sqlite3<4>-Footnote-1634590
Ref: sqlite3<4>-Footnote-2634655
Ref: sqlite3<4>-Footnote-3634720
Ref: sqlite3<4>-Footnote-4634785
Ref: sqlite3<4>-Footnote-5634850
Ref: sqlite3<4>-Footnote-6634915
Ref: sqlite3<4>-Footnote-7634980
Ref: sqlite3<4>-Footnote-8635045
Ref: sqlite3<4>-Footnote-9635110
Ref: sqlite3<4>-Footnote-10635175
Ref: sqlite3<4>-Footnote-11635241
Node: string635307
Ref: whatsnew/3 11 string635403
Ref: 686635403
Ref: whatsnew/3 11 whatsnew311-string635403
Ref: 687635403
Ref: string-Footnote-1635728
Node: sys<4>635783
Ref: whatsnew/3 11 sys635878
Ref: 68b635878
Ref: whatsnew/3 11 whatsnew311-sys635878
Ref: 68c635878
Ref: sys<4>-Footnote-1636571
Ref: sys<4>-Footnote-2636636
Ref: sys<4>-Footnote-3636701
Node: sysconfig636756
Ref: whatsnew/3 11 sysconfig636856
Ref: 690636856
Ref: whatsnew/3 11 whatsnew311-sysconfig636856
Ref: 691636856
Ref: sysconfig-Footnote-1637669
Node: tempfile<3>637734
Ref: whatsnew/3 11 tempfile637840
Ref: 694637840
Ref: whatsnew/3 11 whatsnew311-tempfile637840
Ref: 695637840
Ref: tempfile<3>-Footnote-1638249
Node: threading<2>638304
Ref: whatsnew/3 11 threading638408
Ref: 699638408
Ref: whatsnew/3 11 whatsnew311-threading638408
Ref: 69a638408
Ref: threading<2>-Footnote-1638913
Node: time<2>638978
Ref: whatsnew/3 11 time639081
Ref: 69e639081
Ref: whatsnew/3 11 whatsnew311-time639081
Ref: 69f639081
Ref: time<2>-Footnote-1639882
Ref: time<2>-Footnote-2639947
Ref: time<2>-Footnote-3640044
Ref: time<2>-Footnote-4640109
Node: tkinter<3>640174
Ref: whatsnew/3 11 tkinter640277
Ref: 6a1640277
Ref: whatsnew/3 11 whatsnew311-tkinter640277
Ref: 6a2640277
Ref: tkinter<3>-Footnote-1640560
Node: traceback<2>640615
Ref: whatsnew/3 11 traceback640720
Ref: 6a4640720
Ref: whatsnew/3 11 whatsnew311-traceback640720
Ref: 6a5640720
Ref: traceback<2>-Footnote-1641212
Ref: traceback<2>-Footnote-2641277
Node: typing<4>641342
Ref: whatsnew/3 11 typing641451
Ref: 6a8641451
Ref: whatsnew/3 11 whatsnew311-typing641451
Ref: 6a9641451
Ref: typing<4>-Footnote-1644737
Ref: typing<4>-Footnote-2644792
Ref: typing<4>-Footnote-3644847
Ref: typing<4>-Footnote-4644902
Ref: typing<4>-Footnote-5644957
Ref: typing<4>-Footnote-6645022
Ref: typing<4>-Footnote-7645077
Ref: typing<4>-Footnote-8645132
Ref: typing<4>-Footnote-9645187
Ref: typing<4>-Footnote-10645242
Ref: typing<4>-Footnote-11645298
Ref: typing<4>-Footnote-12645354
Ref: typing<4>-Footnote-13645410
Ref: typing<4>-Footnote-14645466
Ref: typing<4>-Footnote-15645522
Node: unicodedata<3>645578
Ref: whatsnew/3 11 unicodedata645686
Ref: 6b8645686
Ref: whatsnew/3 11 whatsnew311-unicodedata645686
Ref: 6b9645686
Ref: unicodedata<3>-Footnote-1645885
Node: unittest<4>645950
Ref: whatsnew/3 11 unittest646056
Ref: 6ba646056
Ref: whatsnew/3 11 whatsnew311-unittest646056
Ref: 6bb646056
Ref: unittest<4>-Footnote-1646458
Node: venv<2>646523
Ref: whatsnew/3 11 venv646626
Ref: 6c0646626
Ref: whatsnew/3 11 whatsnew311-venv646626
Ref: 6c1646626
Ref: venv<2>-Footnote-1647249
Node: warnings<2>647314
Ref: whatsnew/3 11 warnings647413
Ref: 6c2647413
Ref: whatsnew/3 11 whatsnew311-warnings647413
Ref: 6c3647413
Ref: warnings<2>-Footnote-1647744
Node: zipfile647809
Ref: whatsnew/3 11 whatsnew311-zipfile647892
Ref: 6c5647892
Ref: whatsnew/3 11 zipfile647892
Ref: 6c6647892
Ref: zipfile-Footnote-1648483
Ref: zipfile-Footnote-2648548
Ref: zipfile-Footnote-3648603
Node: Optimizations<3>648658
Ref: whatsnew/3 11 optimizations648789
Ref: 6cd648789
Ref: whatsnew/3 11 whatsnew311-optimizations648789
Ref: 6ce648789
Ref: Optimizations<3>-Footnote-1651201
Ref: Optimizations<3>-Footnote-2651266
Ref: Optimizations<3>-Footnote-3651321
Ref: Optimizations<3>-Footnote-4651376
Ref: Optimizations<3>-Footnote-5651431
Ref: Optimizations<3>-Footnote-6651496
Ref: Optimizations<3>-Footnote-7651551
Ref: Optimizations<3>-Footnote-8651616
Ref: Optimizations<3>-Footnote-9651671
Node: Faster CPython651736
Ref: whatsnew/3 11 faster-cpython651875
Ref: 6d9651875
Ref: whatsnew/3 11 whatsnew311-faster-cpython651875
Ref: 5a3651875
Ref: Faster CPython-Footnote-1652460
Ref: Faster CPython-Footnote-2652526
Node: Faster Startup652574
Ref: whatsnew/3 11 faster-startup652662
Ref: 6dc652662
Ref: whatsnew/3 11 whatsnew311-faster-startup652662
Ref: 6da652662
Node: Frozen imports / Static code objects652760
Ref: whatsnew/3 11 frozen-imports-static-code-objects652847
Ref: 6dd652847
Ref: whatsnew/3 11 whatsnew311-faster-imports652847
Ref: 6de652847
Node: Faster Runtime653681
Ref: whatsnew/3 11 faster-runtime653782
Ref: 6e0653782
Ref: whatsnew/3 11 whatsnew311-faster-runtime653782
Ref: 6db653782
Node: Cheaper lazy Python frames654021
Ref: whatsnew/3 11 cheaper-lazy-python-frames654136
Ref: 6e1654136
Ref: whatsnew/3 11 whatsnew311-lazy-python-frames654136
Ref: 6e2654136
Ref: whatsnew/3 11 inline-calls655079
Ref: 6e6655079
Ref: Cheaper lazy Python frames-Footnote-1655117
Node: Inlined Python function calls655182
Ref: whatsnew/3 11 inlined-python-function-calls655347
Ref: 6e7655347
Ref: whatsnew/3 11 whatsnew311-inline-calls655347
Ref: 6e8655347
Ref: Inlined Python function calls-Footnote-1656303
Node: PEP 659 Specializing Adaptive Interpreter656368
Ref: whatsnew/3 11 pep-659-specializing-adaptive-interpreter656498
Ref: 6e9656498
Ref: whatsnew/3 11 whatsnew311-pep659656498
Ref: 17c656498
Ref: PEP 659 Specializing Adaptive Interpreter-Footnote-1663910
Ref: PEP 659 Specializing Adaptive Interpreter-Footnote-2663952
Ref: PEP 659 Specializing Adaptive Interpreter-Footnote-3663994
Ref: PEP 659 Specializing Adaptive Interpreter-Footnote-4664119
Node: Misc664344
Ref: whatsnew/3 11 misc664434
Ref: 6ea664434
Ref: whatsnew/3 11 whatsnew311-faster-cpython-misc664434
Ref: 6eb664434
Ref: Misc-Footnote-1665451
Ref: Misc-Footnote-2665516
Ref: Misc-Footnote-3665581
Ref: Misc-Footnote-4665646
Ref: Misc-Footnote-5665711
Ref: Misc-Footnote-6665782
Node: FAQ665837
Ref: whatsnew/3 11 faq665918
Ref: 6ed665918
Ref: whatsnew/3 11 whatsnew311-faster-cpython-faq665918
Ref: 6ee665918
Node: How should I write my code to utilize these speedups?666213
Ref: whatsnew/3 11 faster-cpython-faq-my-code666349
Ref: 6ef666349
Ref: whatsnew/3 11 how-should-i-write-my-code-to-utilize-these-speedups666349
Ref: 6f0666349
Node: Will CPython 3 11 use more memory?666644
Ref: whatsnew/3 11 faster-cpython-faq-memory666835
Ref: 6f1666835
Ref: whatsnew/3 11 will-cpython-3-11-use-more-memory666835
Ref: 6f2666835
Node: I don’t see any speedups in my workload Why?667098
Ref: whatsnew/3 11 faster-cpython-ymmv667260
Ref: 6f3667260
Ref: whatsnew/3 11 i-don-t-see-any-speedups-in-my-workload-why667260
Ref: 6f4667260
Node: Is there a JIT compiler?667850
Ref: whatsnew/3 11 faster-cpython-jit667969
Ref: 6f5667969
Ref: whatsnew/3 11 is-there-a-jit-compiler667969
Ref: 6f6667969
Node: About668089
Ref: whatsnew/3 11 about668157
Ref: 6f7668157
Ref: whatsnew/3 11 whatsnew311-faster-cpython-about668157
Ref: 6f8668157
Node: CPython bytecode changes<2>668466
Ref: whatsnew/3 11 cpython-bytecode-changes668602
Ref: 6fa668602
Ref: whatsnew/3 11 whatsnew311-bytecode-changes668602
Ref: 6fb668602
Node: New opcodes669149
Ref: whatsnew/3 11 new-opcodes669249
Ref: 6fd669249
Ref: whatsnew/3 11 whatsnew311-added-opcodes669249
Ref: 6fe669249
Ref: New opcodes-Footnote-1670031
Node: Replaced opcodes670073
Ref: whatsnew/3 11 replaced-opcodes670205
Ref: 707670205
Ref: whatsnew/3 11 whatsnew311-replaced-opcodes670205
Ref: 708670205
Ref: whatsnew/3 11 whatsnew311-changed-opcodes672920
Ref: 711672920
Ref: whatsnew/3 11 whatsnew311-removed-opcodes672920
Ref: 712672920
Ref: Replaced opcodes-Footnote-1672956
Node: Changed/removed opcodes673174
Ref: whatsnew/3 11 changed-removed-opcodes673286
Ref: 713673286
Ref: whatsnew/3 11 whatsnew311-changed-removed-opcodes673286
Ref: 714673286
Ref: whatsnew/3 11 whatsnew311-deprecated673874
Ref: 717673874
Ref: Changed/removed opcodes-Footnote-1673911
Node: Deprecated<3>673966
Ref: whatsnew/3 11 deprecated674118
Ref: 718674118
Ref: whatsnew/3 11 whatsnew311-python-api-deprecated674118
Ref: 719674118
Ref: whatsnew/3 11 whatsnew311-deprecated-language674280
Ref: 71b674280
Node: Language/Builtins674346
Ref: whatsnew/3 11 language-builtins674429
Ref: 71c674429
Ref: whatsnew/3 11 whatsnew311-deprecated-builtins674429
Ref: 71d674429
Ref: Language/Builtins-Footnote-1675650
Ref: Language/Builtins-Footnote-2675715
Ref: Language/Builtins-Footnote-3675770
Ref: Language/Builtins-Footnote-4675825
Node: Modules675890
Ref: whatsnew/3 11 modules675998
Ref: 721675998
Ref: whatsnew/3 11 whatsnew311-deprecated-modules675998
Ref: 722675998
Ref: whatsnew/3 11 whatsnew311-pep594676033
Ref: 5af676033
Ref: Modules-Footnote-1678243
Ref: Modules-Footnote-2678285
Ref: Modules-Footnote-3678350
Ref: Modules-Footnote-4678405
Ref: Modules-Footnote-5678470
Ref: Modules-Footnote-6678512
Ref: Modules-Footnote-7678577
Node: Standard Library678642
Ref: whatsnew/3 11 standard-library678724
Ref: 723678724
Ref: whatsnew/3 11 whatsnew311-deprecated-stdlib678724
Ref: 724678724
Ref: whatsnew/3 11 whatsnew311-pending-removal683581
Ref: 729683581
Ref: Standard Library-Footnote-1683618
Ref: Standard Library-Footnote-2683683
Ref: Standard Library-Footnote-3683748
Ref: Standard Library-Footnote-4683803
Ref: Standard Library-Footnote-5683858
Ref: Standard Library-Footnote-6683913
Ref: Standard Library-Footnote-7683968
Ref: Standard Library-Footnote-8684033
Ref: Standard Library-Footnote-9684088
Ref: Standard Library-Footnote-10684143
Ref: Standard Library-Footnote-11684209
Ref: Standard Library-Footnote-12684274
Node: Pending Removal in Python 3 12684330
Ref: whatsnew/3 11 pending-removal-in-python-3-12684465
Ref: 72a684465
Ref: whatsnew/3 11 whatsnew311-python-api-pending-removal684465
Ref: 72b684465
Ref: whatsnew/3 11 whatsnew311-removed690103
Ref: 730690103
Node: Removed<3>690103
Ref: whatsnew/3 11 removed690247
Ref: 731690247
Ref: whatsnew/3 11 whatsnew311-python-api-removed690247
Ref: 732690247
Ref: whatsnew/3 11 whatsnew311-porting694914
Ref: 73f694914
Ref: Removed<3>-Footnote-1694951
Ref: Removed<3>-Footnote-2695016
Ref: Removed<3>-Footnote-3695081
Ref: Removed<3>-Footnote-4695146
Ref: Removed<3>-Footnote-5695211
Ref: Removed<3>-Footnote-6695276
Ref: Removed<3>-Footnote-7695341
Ref: Removed<3>-Footnote-8695406
Ref: Removed<3>-Footnote-9695471
Ref: Removed<3>-Footnote-10695536
Ref: Removed<3>-Footnote-11695602
Ref: Removed<3>-Footnote-12695668
Ref: Removed<3>-Footnote-13695734
Ref: Removed<3>-Footnote-14695800
Ref: Removed<3>-Footnote-15695842
Node: Porting to Python 3 11695896
Ref: whatsnew/3 11 porting-to-python-3-11696026
Ref: 740696026
Ref: whatsnew/3 11 whatsnew311-python-api-porting696026
Ref: 741696026
Ref: Porting to Python 3 11-Footnote-1699075
Ref: Porting to Python 3 11-Footnote-2699140
Ref: Porting to Python 3 11-Footnote-3699195
Ref: Porting to Python 3 11-Footnote-4699260
Ref: Porting to Python 3 11-Footnote-5699325
Ref: Porting to Python 3 11-Footnote-6699390
Ref: Porting to Python 3 11-Footnote-7699455
Ref: Porting to Python 3 11-Footnote-8699520
Node: Build Changes<3>699585
Ref: whatsnew/3 11 build-changes699721
Ref: 74c699721
Ref: whatsnew/3 11 whatsnew311-build-changes699721
Ref: 74d699721
Ref: Build Changes<3>-Footnote-1703960
Ref: Build Changes<3>-Footnote-2704002
Ref: Build Changes<3>-Footnote-3704051
Ref: Build Changes<3>-Footnote-4704084
Ref: Build Changes<3>-Footnote-5704116
Ref: Build Changes<3>-Footnote-6704142
Ref: Build Changes<3>-Footnote-7704171
Ref: Build Changes<3>-Footnote-8704226
Ref: Build Changes<3>-Footnote-9704281
Ref: Build Changes<3>-Footnote-10704336
Ref: Build Changes<3>-Footnote-11704380
Ref: Build Changes<3>-Footnote-12704464
Ref: Build Changes<3>-Footnote-13704530
Ref: Build Changes<3>-Footnote-14704596
Ref: Build Changes<3>-Footnote-15704662
Ref: Build Changes<3>-Footnote-16704710
Ref: Build Changes<3>-Footnote-17704776
Ref: Build Changes<3>-Footnote-18704842
Ref: Build Changes<3>-Footnote-19704870
Ref: Build Changes<3>-Footnote-20704936
Ref: Build Changes<3>-Footnote-21704999
Ref: Build Changes<3>-Footnote-22705027
Ref: Build Changes<3>-Footnote-23705093
Ref: Build Changes<3>-Footnote-24705159
Ref: Build Changes<3>-Footnote-25705225
Ref: Build Changes<3>-Footnote-26705291
Ref: Build Changes<3>-Footnote-27705341
Ref: Build Changes<3>-Footnote-28705407
Ref: Build Changes<3>-Footnote-29705473
Ref: Build Changes<3>-Footnote-30705539
Ref: Build Changes<3>-Footnote-31705605
Ref: Build Changes<3>-Footnote-32705671
Ref: Build Changes<3>-Footnote-33705737
Node: C API Changes<3>705803
Ref: whatsnew/3 11 c-api-changes705942
Ref: 751705942
Ref: whatsnew/3 11 whatsnew311-c-api705942
Ref: 752705942
Node: New Features<6>706202
Ref: whatsnew/3 11 id5706304
Ref: 753706304
Ref: whatsnew/3 11 whatsnew311-c-api-new-features706304
Ref: 754706304
Ref: New Features<6>-Footnote-1709158
Ref: New Features<6>-Footnote-2709223
Ref: New Features<6>-Footnote-3709288
Ref: New Features<6>-Footnote-4709353
Ref: New Features<6>-Footnote-5709418
Ref: New Features<6>-Footnote-6709483
Ref: New Features<6>-Footnote-7709548
Ref: New Features<6>-Footnote-8709613
Ref: New Features<6>-Footnote-9709678
Node: Porting to Python 3 11<2>709733
Ref: whatsnew/3 11 id6709857
Ref: 777709857
Ref: whatsnew/3 11 whatsnew311-c-api-porting709857
Ref: 742709857
Ref: whatsnew/3 11 whatsnew311-pep670709922
Ref: 5b1709922
Ref: whatsnew/3 11 pyframeobject-3-11-hiding717339
Ref: 78b717339
Ref: Porting to Python 3 11<2>-Footnote-1723296
Ref: Porting to Python 3 11<2>-Footnote-2723359
Ref: Porting to Python 3 11<2>-Footnote-3723401
Ref: Porting to Python 3 11<2>-Footnote-4723456
Ref: Porting to Python 3 11<2>-Footnote-5723521
Ref: Porting to Python 3 11<2>-Footnote-6723586
Ref: Porting to Python 3 11<2>-Footnote-7723651
Ref: Porting to Python 3 11<2>-Footnote-8723693
Ref: Porting to Python 3 11<2>-Footnote-9723758
Ref: Porting to Python 3 11<2>-Footnote-10723813
Ref: Porting to Python 3 11<2>-Footnote-11723869
Ref: Porting to Python 3 11<2>-Footnote-12723935
Ref: Porting to Python 3 11<2>-Footnote-13723978
Ref: Porting to Python 3 11<2>-Footnote-14724044
Ref: Porting to Python 3 11<2>-Footnote-15724110
Ref: Porting to Python 3 11<2>-Footnote-16724176
Ref: Porting to Python 3 11<2>-Footnote-17724242
Ref: Porting to Python 3 11<2>-Footnote-18724308
Ref: Porting to Python 3 11<2>-Footnote-19724374
Ref: Porting to Python 3 11<2>-Footnote-20724430
Ref: Porting to Python 3 11<2>-Footnote-21724483
Ref: Porting to Python 3 11<2>-Footnote-22724549
Ref: Porting to Python 3 11<2>-Footnote-23724615
Ref: Porting to Python 3 11<2>-Footnote-24724668
Node: Deprecated<4>724701
Ref: whatsnew/3 11 id7724843
Ref: 794724843
Ref: whatsnew/3 11 whatsnew311-c-api-deprecated724843
Ref: 71a724843
Ref: Deprecated<4>-Footnote-1725812
Ref: Deprecated<4>-Footnote-2725854
Ref: Deprecated<4>-Footnote-3725909
Node: Pending Removal in Python 3 12<2>725974
Ref: whatsnew/3 11 id8726101
Ref: 796726101
Ref: whatsnew/3 11 whatsnew311-c-api-pending-removal726101
Ref: 72c726101
Node: Removed<4>726851
Ref: whatsnew/3 11 id9726956
Ref: 798726956
Ref: whatsnew/3 11 whatsnew311-c-api-removed726956
Ref: 733726956
Ref: whatsnew/3 11 whatsnew311-pep624729216
Ref: 5b0729216
Ref: Removed<4>-Footnote-1730156
Ref: Removed<4>-Footnote-2730221
Ref: Removed<4>-Footnote-3730286
Ref: Removed<4>-Footnote-4730351
Ref: Removed<4>-Footnote-5730416
Ref: Removed<4>-Footnote-6730481
Ref: Removed<4>-Footnote-7730546
Ref: Removed<4>-Footnote-8730611
Ref: Removed<4>-Footnote-9730676
Ref: Removed<4>-Footnote-10730741
Ref: Removed<4>-Footnote-11730784
Ref: Removed<4>-Footnote-12730844
Node: Notable changes in 3 11 4730910
Ref: whatsnew/3 11 notable-changes-in-3-11-4731058
Ref: 79e731058
Node: tarfile<2>731158
Ref: whatsnew/3 11 tarfile731230
Ref: 79f731230
Ref: tarfile<2>-Footnote-1731834
Node: Notable changes in 3 11 5731876
Ref: whatsnew/3 11 notable-changes-in-3-11-5731999
Ref: 7a0731999
Node: OpenSSL732088
Ref: whatsnew/3 11 openssl732157
Ref: 7a1732157
Node: What’s New In Python 3 10732276
Ref: whatsnew/3 10 doc732433
Ref: 7a2732433
Ref: whatsnew/3 10 translation-repo732433
Ref: 7a3732433
Ref: whatsnew/3 10 what-s-new-in-python-3-10732433
Ref: 7a4732433
Node: Summary – Release highlights<3>733479
Ref: whatsnew/3 10 summary-release-highlights733600
Ref: 7a5733600
Ref: Summary – Release highlights<3>-Footnote-1734753
Ref: Summary – Release highlights<3>-Footnote-2734795
Ref: Summary – Release highlights<3>-Footnote-3734837
Ref: Summary – Release highlights<3>-Footnote-4734879
Ref: Summary – Release highlights<3>-Footnote-5734944
Ref: Summary – Release highlights<3>-Footnote-6734986
Ref: Summary – Release highlights<3>-Footnote-7735028
Ref: Summary – Release highlights<3>-Footnote-8735070
Ref: Summary – Release highlights<3>-Footnote-9735112
Ref: Summary – Release highlights<3>-Footnote-10735154
Ref: Summary – Release highlights<3>-Footnote-11735197
Ref: Summary – Release highlights<3>-Footnote-12735240
Ref: Summary – Release highlights<3>-Footnote-13735283
Ref: Summary – Release highlights<3>-Footnote-14735326
Ref: Summary – Release highlights<3>-Footnote-15735369
Node: New Features<7>735412
Ref: whatsnew/3 10 new-features735579
Ref: 7a6735579
Node: Parenthesized context managers735947
Ref: whatsnew/3 10 parenthesized-context-managers736059
Ref: 7a7736059
Ref: whatsnew/3 10 whatsnew310-pep563736059
Ref: 7a8736059
Ref: Parenthesized context managers-Footnote-1737303
Ref: Parenthesized context managers-Footnote-2737345
Ref: Parenthesized context managers-Footnote-3737410
Node: Better error messages737475
Ref: whatsnew/3 10 better-error-messages737654
Ref: 7a9737654
Node: SyntaxErrors737799
Ref: whatsnew/3 10 syntaxerrors737895
Ref: 7aa737895
Ref: SyntaxErrors-Footnote-1743232
Ref: SyntaxErrors-Footnote-2743297
Ref: SyntaxErrors-Footnote-3743362
Ref: SyntaxErrors-Footnote-4743427
Ref: SyntaxErrors-Footnote-5743492
Ref: SyntaxErrors-Footnote-6743557
Ref: SyntaxErrors-Footnote-7743622
Ref: SyntaxErrors-Footnote-8743687
Ref: SyntaxErrors-Footnote-9743752
Ref: SyntaxErrors-Footnote-10743817
Ref: SyntaxErrors-Footnote-11743883
Node: IndentationErrors743949
Ref: whatsnew/3 10 indentationerrors744069
Ref: 7ab744069
Node: AttributeErrors744486
Ref: whatsnew/3 10 attributeerrors744604
Ref: 7ad744604
Ref: AttributeErrors-Footnote-1745357
Node: NameErrors745422
Ref: whatsnew/3 10 nameerrors745514
Ref: 7ae745514
Ref: NameErrors-Footnote-1746327
Node: PEP 626 Precise line numbers for debugging and other tools746392
Ref: whatsnew/3 10 pep-626-precise-line-numbers-for-debugging-and-other-tools746576
Ref: 7af746576
Node: PEP 634 Structural Pattern Matching747271
Ref: whatsnew/3 10 pep-634-structural-pattern-matching747487
Ref: 7b1747487
Node: Syntax and operations748274
Ref: whatsnew/3 10 syntax-and-operations748396
Ref: 7b2748396
Node: Declarative approach749462
Ref: whatsnew/3 10 declarative-approach749626
Ref: 7b3749626
Node: Simple pattern match to a literal750805
Ref: whatsnew/3 10 simple-pattern-match-to-a-literal750984
Ref: 7b4750984
Node: Behavior without the wildcard752359
Ref: whatsnew/3 10 behavior-without-the-wildcard752458
Ref: 7b5752458
Node: Patterns with a literal and variable753040
Ref: whatsnew/3 10 patterns-with-a-literal-and-variable753219
Ref: 7b6753219
Node: Patterns and classes754187
Ref: whatsnew/3 10 patterns-and-classes754348
Ref: 7b7754348
Node: Patterns with positional parameters755287
Ref: whatsnew/3 10 patterns-with-positional-parameters755379
Ref: 7b8755379
Node: Nested patterns755968
Ref: whatsnew/3 10 nested-patterns756126
Ref: 7b9756126
Node: Complex patterns and the wildcard756765
Ref: whatsnew/3 10 complex-patterns-and-the-wildcard756908
Ref: 7ba756908
Node: Guard757482
Ref: whatsnew/3 10 guard757628
Ref: 7bb757628
Node: Other Key Features758072
Ref: whatsnew/3 10 other-key-features758176
Ref: 7bc758176
Ref: Other Key Features-Footnote-1760348
Ref: Other Key Features-Footnote-2760390
Ref: Other Key Features-Footnote-3760432
Node: Optional EncodingWarning and encoding="locale" option760474
Ref: whatsnew/3 10 optional-encodingwarning-and-encoding-locale-option760623
Ref: 7bd760623
Ref: whatsnew/3 10 whatsnew310-pep597760623
Ref: 7be760623
Node: New Features Related to Type Hints<3>761523
Ref: whatsnew/3 10 new-feat-related-type-hints761682
Ref: 7c2761682
Ref: whatsnew/3 10 new-features-related-to-type-hints761682
Ref: 7c3761682
Ref: New Features Related to Type Hints<3>-Footnote-1762183
Node: PEP 604 New Type Union Operator762225
Ref: whatsnew/3 10 pep-604-new-type-union-operator762380
Ref: 7c4762380
Ref: PEP 604 New Type Union Operator-Footnote-1763454
Ref: PEP 604 New Type Union Operator-Footnote-2763496
Ref: PEP 604 New Type Union Operator-Footnote-3763561
Node: PEP 612 Parameter Specification Variables763626
Ref: whatsnew/3 10 pep-612-parameter-specification-variables763807
Ref: 7c7763807
Ref: PEP 612 Parameter Specification Variables-Footnote-1765094
Ref: PEP 612 Parameter Specification Variables-Footnote-2765136
Ref: PEP 612 Parameter Specification Variables-Footnote-3765178
Ref: PEP 612 Parameter Specification Variables-Footnote-4765243
Node: PEP 613 TypeAlias765308
Ref: whatsnew/3 10 pep-613-typealias765490
Ref: 7cc765490
Ref: PEP 613 TypeAlias-Footnote-1766318
Ref: PEP 613 TypeAlias-Footnote-2766360
Ref: PEP 613 TypeAlias-Footnote-3766402
Node: PEP 647 User-Defined Type Guards766467
Ref: whatsnew/3 10 pep-647-user-defined-type-guards766599
Ref: 7ce766599
Ref: PEP 647 User-Defined Type Guards-Footnote-1767081
Ref: PEP 647 User-Defined Type Guards-Footnote-2767123
Node: Other Language Changes<4>767188
Ref: whatsnew/3 10 other-language-changes767346
Ref: 7cf767346
Ref: Other Language Changes<4>-Footnote-1772030
Ref: Other Language Changes<4>-Footnote-2772095
Ref: Other Language Changes<4>-Footnote-3772160
Ref: Other Language Changes<4>-Footnote-4772202
Ref: Other Language Changes<4>-Footnote-5772267
Ref: Other Language Changes<4>-Footnote-6772332
Ref: Other Language Changes<4>-Footnote-7772397
Ref: Other Language Changes<4>-Footnote-8772462
Ref: Other Language Changes<4>-Footnote-9772527
Ref: Other Language Changes<4>-Footnote-10772569
Ref: Other Language Changes<4>-Footnote-11772635
Ref: Other Language Changes<4>-Footnote-12772701
Ref: Other Language Changes<4>-Footnote-13772767
Ref: Other Language Changes<4>-Footnote-14772833
Ref: Other Language Changes<4>-Footnote-15772899
Ref: Other Language Changes<4>-Footnote-16772965
Node: New Modules<4>773031
Ref: whatsnew/3 10 new-modules773171
Ref: 7df773171
Node: Improved Modules<4>773220
Ref: whatsnew/3 10 improved-modules773351
Ref: 7e0773351
Node: asyncio<4>774460
Ref: whatsnew/3 10 asyncio774546
Ref: 7e1774546
Ref: asyncio<4>-Footnote-1774724
Node: argparse<2>774789
Ref: whatsnew/3 10 argparse774892
Ref: 7e3774892
Ref: argparse<2>-Footnote-1775182
Node: array<3>775246
Ref: whatsnew/3 10 array775362
Ref: 7e4775362
Ref: array<3>-Footnote-1775604
Node: asynchat asyncore smtpd775669
Ref: whatsnew/3 10 asynchat-asyncore-smtpd775783
Ref: 7e6775783
Node: base64<2>776043
Ref: whatsnew/3 10 base64776152
Ref: 7e7776152
Node: bdb776319
Ref: whatsnew/3 10 bdb776411
Ref: 7ea776411
Ref: bdb-Footnote-1776580
Node: bisect776645
Ref: whatsnew/3 10 bisect776734
Ref: 7eb776734
Ref: bisect-Footnote-1776951
Node: codecs777015
Ref: whatsnew/3 10 codecs777116
Ref: 7ec777116
Ref: codecs-Footnote-1777313
Node: collections abc777378
Ref: whatsnew/3 10 collections-abc777486
Ref: 7ee777486
Ref: collections abc-Footnote-1778383
Node: contextlib<2>778448
Ref: whatsnew/3 10 contextlib778556
Ref: 7f1778556
Ref: contextlib<2>-Footnote-1779078
Ref: contextlib<2>-Footnote-2779143
Node: curses779208
Ref: whatsnew/3 10 curses779315
Ref: 7f5779315
Ref: curses-Footnote-1780012
Ref: curses-Footnote-2780077
Node: dataclasses<2>780142
Ref: whatsnew/3 10 dataclasses780248
Ref: 7fb780248
Node: __slots__780339
Ref: whatsnew/3 10 slots780427
Ref: 7fc780427
Ref: __slots__-Footnote-1780629
Node: Keyword-only fields780694
Ref: whatsnew/3 10 keyword-only-fields780782
Ref: 7fd780782
Ref: Keyword-only fields-Footnote-1782255
Node: distutils<2>782320
Ref: whatsnew/3 10 distutils782430
Ref: 7fe782430
Ref: whatsnew/3 10 distutils-deprecated782430
Ref: 72d782430
Ref: distutils<2>-Footnote-1783338
Ref: distutils<2>-Footnote-2783380
Node: doctest<2>783445
Ref: whatsnew/3 10 doctest783550
Ref: 7ff783550
Ref: doctest<2>-Footnote-1783754
Node: encodings783819
Ref: whatsnew/3 10 encodings783919
Ref: 800783919
Ref: encodings-Footnote-1784115
Node: enum<4>784180
Ref: whatsnew/3 10 enum784279
Ref: 802784279
Ref: enum<4>-Footnote-1784752
Ref: enum<4>-Footnote-2784817
Node: fileinput784882
Ref: whatsnew/3 10 fileinput784984
Ref: 804784984
Ref: fileinput-Footnote-1785419
Ref: fileinput-Footnote-2785484
Node: faulthandler785548
Ref: whatsnew/3 10 faulthandler785645
Ref: 807785645
Ref: faulthandler-Footnote-1785887
Node: gc785952
Ref: whatsnew/3 10 gc786047
Ref: 808786047
Ref: gc-Footnote-1786272
Node: glob<2>786337
Ref: whatsnew/3 10 glob786430
Ref: 80c786430
Ref: glob<2>-Footnote-1786694
Node: hashlib<3>786759
Ref: whatsnew/3 10 hashlib786854
Ref: 80e786854
Ref: hashlib<3>-Footnote-1787397
Ref: hashlib<3>-Footnote-2787439
Ref: hashlib<3>-Footnote-3787504
Ref: hashlib<3>-Footnote-4787569
Node: hmac787634
Ref: whatsnew/3 10 hmac787741
Ref: 80f787741
Ref: hmac-Footnote-1787927
Node: IDLE and idlelib<2>787992
Ref: whatsnew/3 10 idle-and-idlelib788110
Ref: 810788110
Ref: IDLE and idlelib<2>-Footnote-1790195
Ref: IDLE and idlelib<2>-Footnote-2790260
Ref: IDLE and idlelib<2>-Footnote-3790325
Ref: IDLE and idlelib<2>-Footnote-4790390
Ref: IDLE and idlelib<2>-Footnote-5790455
Ref: IDLE and idlelib<2>-Footnote-6790520
Ref: IDLE and idlelib<2>-Footnote-7790585
Ref: IDLE and idlelib<2>-Footnote-8790650
Node: importlib metadata<2>790705
Ref: whatsnew/3 10 importlib-metadata790829
Ref: 815790829
Ref: importlib metadata<2>-Footnote-1791423
Node: inspect<3>791496
Ref: whatsnew/3 10 inspect791613
Ref: 818791613
Ref: inspect<3>-Footnote-1792785
Ref: inspect<3>-Footnote-2792850
Node: itertools<3>792915
Ref: whatsnew/3 10 itertools793020
Ref: 81a793020
Ref: itertools<3>-Footnote-1793186
Node: linecache793251
Ref: whatsnew/3 10 linecache793351
Ref: 81c793351
Ref: linecache-Footnote-1793559
Node: os<4>793624
Ref: whatsnew/3 10 os793722
Ref: 81d793722
Ref: os<4>-Footnote-1794461
Ref: os<4>-Footnote-2794526
Ref: os<4>-Footnote-3794591
Ref: os<4>-Footnote-4794656
Node: os path<4>794721
Ref: whatsnew/3 10 os-path794820
Ref: 824794820
Ref: os path<4>-Footnote-1795131
Node: pathlib<5>795196
Ref: whatsnew/3 10 pathlib795301
Ref: 825795301
Ref: pathlib<5>-Footnote-1796010
Ref: pathlib<5>-Footnote-2796075
Ref: pathlib<5>-Footnote-3796140
Ref: pathlib<5>-Footnote-4796205
Node: platform<2>796270
Ref: whatsnew/3 10 platform796371
Ref: 82b796371
Ref: platform<2>-Footnote-1796640
Ref: platform<2>-Footnote-2796713
Node: pprint796778
Ref: whatsnew/3 10 pprint796879
Ref: 82d796879
Ref: pprint-Footnote-1797213
Ref: pprint-Footnote-2797278
Node: py_compile797343
Ref: whatsnew/3 10 py-compile797439
Ref: 82f797439
Ref: py_compile-Footnote-1797647
Node: pyclbr797712
Ref: whatsnew/3 10 pyclbr797808
Ref: 830797808
Ref: pyclbr-Footnote-1798152
Node: shelve798217
Ref: whatsnew/3 10 shelve798316
Ref: 833798316
Ref: shelve-Footnote-1798589
Node: statistics<3>798654
Ref: whatsnew/3 10 statistics798754
Ref: 835798754
Ref: statistics<3>-Footnote-1799009
Node: site<2>799074
Ref: whatsnew/3 10 site799177
Ref: 838799177
Ref: site<2>-Footnote-1799375
Node: socket<2>799440
Ref: whatsnew/3 10 socket799536
Ref: 839799536
Ref: socket<2>-Footnote-1799982
Ref: socket<2>-Footnote-2800047
Ref: socket<2>-Footnote-3800112
Node: ssl<3>800177
Ref: whatsnew/3 10 ssl800276
Ref: 83c800276
Ref: ssl<3>-Footnote-1802117
Ref: ssl<3>-Footnote-2802159
Ref: ssl<3>-Footnote-3802224
Ref: ssl<3>-Footnote-4802289
Ref: ssl<3>-Footnote-5802354
Ref: ssl<3>-Footnote-6802419
Ref: ssl<3>-Footnote-7802484
Ref: ssl<3>-Footnote-8802549
Ref: ssl<3>-Footnote-9802614
Ref: ssl<3>-Footnote-10802679
Ref: ssl<3>-Footnote-11802745
Ref: ssl<3>-Footnote-12802811
Ref: ssl<3>-Footnote-13802877
Ref: ssl<3>-Footnote-14802943
Ref: ssl<3>-Footnote-15803009
Node: sqlite3<5>803075
Ref: whatsnew/3 10 sqlite3803171
Ref: 843803171
Ref: sqlite3<5>-Footnote-1803407
Node: sys<5>803472
Ref: whatsnew/3 10 sys803569
Ref: 845803569
Ref: sys<5>-Footnote-1803954
Ref: sys<5>-Footnote-2804019
Node: _thread804084
Ref: whatsnew/3 10 thread804183
Ref: 848804183
Ref: _thread-Footnote-1804439
Node: threading<3>804504
Ref: whatsnew/3 10 threading804609
Ref: 84b804609
Ref: threading<3>-Footnote-1805151
Ref: threading<3>-Footnote-2805216
Node: traceback<3>805281
Ref: whatsnew/3 10 traceback805387
Ref: 852805387
Ref: traceback<3>-Footnote-1805715
Node: types<3>805780
Ref: whatsnew/3 10 types805883
Ref: 856805883
Ref: types<3>-Footnote-1806192
Node: typing<5>806257
Ref: whatsnew/3 10 typing806359
Ref: 85a806359
Ref: typing<5>-Footnote-1808579
Ref: typing<5>-Footnote-2808621
Ref: typing<5>-Footnote-3808686
Ref: typing<5>-Footnote-4808751
Ref: typing<5>-Footnote-5808816
Node: unittest<5>808881
Ref: whatsnew/3 10 unittest808987
Ref: 85d808987
Ref: unittest<5>-Footnote-1809203
Node: urllib parse809268
Ref: whatsnew/3 10 urllib-parse809371
Ref: 860809371
Ref: urllib parse-Footnote-1810520
Ref: urllib parse-Footnote-2810585
Ref: urllib parse-Footnote-3810644
Node: xml<2>810699
Ref: whatsnew/3 10 xml810803
Ref: 861810803
Ref: xml<2>-Footnote-1811019
Node: zipimport<3>811084
Ref: whatsnew/3 10 zipimport811167
Ref: 863811167
Ref: zipimport<3>-Footnote-1811547
Ref: zipimport<3>-Footnote-2811589
Ref: zipimport<3>-Footnote-3811654
Node: Optimizations<4>811719
Ref: whatsnew/3 10 optimizations811849
Ref: 867811849
Ref: Optimizations<4>-Footnote-1815341
Ref: Optimizations<4>-Footnote-2815406
Ref: Optimizations<4>-Footnote-3815471
Ref: Optimizations<4>-Footnote-4815536
Ref: Optimizations<4>-Footnote-5815601
Ref: Optimizations<4>-Footnote-6815666
Ref: Optimizations<4>-Footnote-7815787
Ref: Optimizations<4>-Footnote-8815852
Ref: Optimizations<4>-Footnote-9815917
Ref: Optimizations<4>-Footnote-10815982
Ref: Optimizations<4>-Footnote-11816048
Ref: Optimizations<4>-Footnote-12816114
Ref: Optimizations<4>-Footnote-13816157
Ref: Optimizations<4>-Footnote-14816223
Ref: Optimizations<4>-Footnote-15816289
Ref: Optimizations<4>-Footnote-16816355
Ref: Optimizations<4>-Footnote-17816421
Ref: Optimizations<4>-Footnote-18816487
Node: Deprecated<5>816553
Ref: whatsnew/3 10 deprecated816674
Ref: 86e816674
Ref: whatsnew/3 10 whatsnew310-deprecated816674
Ref: 841816674
Ref: Deprecated<5>-Footnote-1826089
Ref: Deprecated<5>-Footnote-2826154
Ref: Deprecated<5>-Footnote-3826219
Ref: Deprecated<5>-Footnote-4826284
Ref: Deprecated<5>-Footnote-5826349
Ref: Deprecated<5>-Footnote-6826414
Ref: Deprecated<5>-Footnote-7826479
Ref: Deprecated<5>-Footnote-8826544
Ref: Deprecated<5>-Footnote-9826609
Ref: Deprecated<5>-Footnote-10826674
Ref: Deprecated<5>-Footnote-11826740
Ref: Deprecated<5>-Footnote-12826806
Ref: Deprecated<5>-Footnote-13826872
Ref: Deprecated<5>-Footnote-14826938
Ref: Deprecated<5>-Footnote-15826997
Ref: Deprecated<5>-Footnote-16827063
Ref: Deprecated<5>-Footnote-17827119
Ref: Deprecated<5>-Footnote-18827185
Ref: Deprecated<5>-Footnote-19827251
Ref: Deprecated<5>-Footnote-20827317
Node: Removed<5>827383
Ref: whatsnew/3 10 removed827510
Ref: 87c827510
Ref: whatsnew/3 10 whatsnew310-removed827510
Ref: 87d827510
Ref: Removed<5>-Footnote-1830750
Ref: Removed<5>-Footnote-2830815
Ref: Removed<5>-Footnote-3830880
Ref: Removed<5>-Footnote-4830945
Ref: Removed<5>-Footnote-5831010
Ref: Removed<5>-Footnote-6831075
Ref: Removed<5>-Footnote-7831140
Node: Porting to Python 3 10831205
Ref: whatsnew/3 10 porting-to-python-3-10831346
Ref: 882831346
Node: Changes in the Python syntax831665
Ref: whatsnew/3 10 changes-in-the-python-syntax831789
Ref: 883831789
Ref: Changes in the Python syntax-Footnote-1832384
Node: Changes in the Python API<3>832449
Ref: whatsnew/3 10 changes-in-the-python-api832605
Ref: 884832605
Ref: whatsnew/3 10 changes-python-api832605
Ref: 881832605
Ref: Changes in the Python API<3>-Footnote-1835527
Ref: Changes in the Python API<3>-Footnote-2835592
Ref: Changes in the Python API<3>-Footnote-3835657
Ref: Changes in the Python API<3>-Footnote-4835722
Ref: Changes in the Python API<3>-Footnote-5835787
Ref: Changes in the Python API<3>-Footnote-6835852
Node: Changes in the C API<2>835917
Ref: whatsnew/3 10 changes-in-the-c-api836036
Ref: 88b836036
Node: CPython bytecode changes<3>838508
Ref: whatsnew/3 10 cpython-bytecode-changes838655
Ref: 891838655
Ref: CPython bytecode changes<3>-Footnote-1838954
Node: Build Changes<4>839019
Ref: whatsnew/3 10 build-changes839160
Ref: 892839160
Ref: Build Changes<4>-Footnote-1841624
Ref: Build Changes<4>-Footnote-2841666
Ref: Build Changes<4>-Footnote-3841731
Ref: Build Changes<4>-Footnote-4841796
Ref: Build Changes<4>-Footnote-5841861
Ref: Build Changes<4>-Footnote-6841926
Ref: Build Changes<4>-Footnote-7841991
Ref: Build Changes<4>-Footnote-8842056
Ref: Build Changes<4>-Footnote-9842121
Ref: Build Changes<4>-Footnote-10842186
Ref: Build Changes<4>-Footnote-11842252
Node: C API Changes<4>842318
Ref: whatsnew/3 10 c-api-changes842466
Ref: 897842466
Node: PEP 652 Maintaining the Stable ABI842732
Ref: whatsnew/3 10 pep-652-maintaining-the-stable-abi842843
Ref: 898842843
Ref: PEP 652 Maintaining the Stable ABI-Footnote-1843276
Ref: PEP 652 Maintaining the Stable ABI-Footnote-2843318
Node: New Features<8>843383
Ref: whatsnew/3 10 id1843528
Ref: 899843528
Ref: New Features<8>-Footnote-1848155
Ref: New Features<8>-Footnote-2848220
Ref: New Features<8>-Footnote-3848285
Ref: New Features<8>-Footnote-4848350
Ref: New Features<8>-Footnote-5848415
Ref: New Features<8>-Footnote-6848480
Ref: New Features<8>-Footnote-7848545
Ref: New Features<8>-Footnote-8848612
Ref: New Features<8>-Footnote-9848677
Ref: New Features<8>-Footnote-10848742
Ref: New Features<8>-Footnote-11848808
Ref: New Features<8>-Footnote-12848874
Ref: New Features<8>-Footnote-13848940
Ref: New Features<8>-Footnote-14849006
Ref: New Features<8>-Footnote-15849072
Ref: New Features<8>-Footnote-16849138
Ref: New Features<8>-Footnote-17849204
Ref: New Features<8>-Footnote-18849270
Node: Porting to Python 3 10<2>849336
Ref: whatsnew/3 10 id2849460
Ref: 8ae849460
Ref: Porting to Python 3 10<2>-Footnote-1853140
Ref: Porting to Python 3 10<2>-Footnote-2853182
Ref: Porting to Python 3 10<2>-Footnote-3853247
Ref: Porting to Python 3 10<2>-Footnote-4853312
Ref: Porting to Python 3 10<2>-Footnote-5853377
Ref: Porting to Python 3 10<2>-Footnote-6853442
Ref: Porting to Python 3 10<2>-Footnote-7853507
Ref: Porting to Python 3 10<2>-Footnote-8853572
Ref: Porting to Python 3 10<2>-Footnote-9853637
Ref: Porting to Python 3 10<2>-Footnote-10853702
Ref: Porting to Python 3 10<2>-Footnote-11853768
Node: Deprecated<6>853834
Ref: whatsnew/3 10 id3853953
Ref: 8b8853953
Ref: Deprecated<6>-Footnote-1854252
Node: Removed<6>854317
Ref: whatsnew/3 10 id4854402
Ref: 8ba854402
Ref: Removed<6>-Footnote-1859406
Ref: Removed<6>-Footnote-2859471
Ref: Removed<6>-Footnote-3859513
Ref: Removed<6>-Footnote-4859578
Ref: Removed<6>-Footnote-5859643
Ref: Removed<6>-Footnote-6859708
Ref: Removed<6>-Footnote-7859773
Ref: Removed<6>-Footnote-8859838
Ref: Removed<6>-Footnote-9859903
Ref: Removed<6>-Footnote-10859945
Ref: Removed<6>-Footnote-11860011
Ref: Removed<6>-Footnote-12860077
Ref: Removed<6>-Footnote-13860143
Ref: Removed<6>-Footnote-14860209
Ref: Removed<6>-Footnote-15860275
Ref: Removed<6>-Footnote-16860341
Node: Notable security feature in 3 10 7860407
Ref: whatsnew/3 10 notable-security-feature-in-3-10-7860573
Ref: 8c7860573
Ref: Notable security feature in 3 10 7-Footnote-1861303
Node: Notable security feature in 3 10 8861359
Ref: whatsnew/3 10 notable-security-feature-in-3-10-8861535
Ref: 8c8861535
Ref: Notable security feature in 3 10 8-Footnote-1861957
Node: Notable changes in 3 10 12862012
Ref: whatsnew/3 10 notable-changes-in-3-10-12862145
Ref: 8c9862145
Node: tarfile<3>862247
Ref: whatsnew/3 10 tarfile862320
Ref: 8ca862320
Ref: tarfile<3>-Footnote-1862924
Node: What’s New In Python 3 9862966
Ref: whatsnew/3 9 doc863122
Ref: 8cb863122
Ref: whatsnew/3 9 translation-repo863122
Ref: 8cc863122
Ref: whatsnew/3 9 what-s-new-in-python-3-9863122
Ref: 8cd863122
Ref: What’s New In Python 3 9-Footnote-1864370
Node: Summary – Release highlights<4>864412
Ref: whatsnew/3 9 summary-release-highlights864569
Ref: 8ce864569
Ref: Summary – Release highlights<4>-Footnote-1866523
Ref: Summary – Release highlights<4>-Footnote-2866565
Ref: Summary – Release highlights<4>-Footnote-3866607
Ref: Summary – Release highlights<4>-Footnote-4866649
Ref: Summary – Release highlights<4>-Footnote-5866691
Ref: Summary – Release highlights<4>-Footnote-6866733
Ref: Summary – Release highlights<4>-Footnote-7866775
Ref: Summary – Release highlights<4>-Footnote-8866817
Ref: Summary – Release highlights<4>-Footnote-9866859
Ref: Summary – Release highlights<4>-Footnote-10866901
Node: You should check for DeprecationWarning in your code866944
Ref: whatsnew/3 9 you-should-check-for-deprecationwarning-in-your-code867125
Ref: 8cf867125
Node: New Features<9>868803
Ref: whatsnew/3 9 new-features868976
Ref: 8d5868976
Node: Dictionary Merge & Update Operators869185
Ref: whatsnew/3 9 dictionary-merge-update-operators869331
Ref: 8d6869331
Ref: Dictionary Merge & Update Operators-Footnote-1870086
Ref: Dictionary Merge & Update Operators-Footnote-2870128
Node: New String Methods to Remove Prefixes and Suffixes870193
Ref: whatsnew/3 9 new-string-methods-to-remove-prefixes-and-suffixes870393
Ref: 8d7870393
Ref: New String Methods to Remove Prefixes and Suffixes-Footnote-1870904
Ref: New String Methods to Remove Prefixes and Suffixes-Footnote-2870946
Node: Type Hinting Generics in Standard Collections871011
Ref: whatsnew/3 9 type-hinting-generics-in-standard-collections871186
Ref: 8da871186
Ref: Type Hinting Generics in Standard Collections-Footnote-1871888
Ref: Type Hinting Generics in Standard Collections-Footnote-2871930
Node: New Parser871995
Ref: whatsnew/3 9 new-parser872111
Ref: 8db872111
Ref: New Parser-Footnote-1873046
Ref: New Parser-Footnote-2873111
Ref: New Parser-Footnote-3873159
Ref: New Parser-Footnote-4873201
Node: Other Language Changes<5>873266
Ref: whatsnew/3 9 other-language-changes873401
Ref: 8dc873401
Ref: Other Language Changes<5>-Footnote-1876503
Ref: Other Language Changes<5>-Footnote-2876568
Ref: Other Language Changes<5>-Footnote-3876633
Ref: Other Language Changes<5>-Footnote-4876698
Ref: Other Language Changes<5>-Footnote-5876763
Ref: Other Language Changes<5>-Footnote-6876805
Ref: Other Language Changes<5>-Footnote-7876870
Ref: Other Language Changes<5>-Footnote-8876935
Ref: Other Language Changes<5>-Footnote-9877000
Ref: Other Language Changes<5>-Footnote-10877065
Ref: Other Language Changes<5>-Footnote-11877131
Node: New Modules<5>877197
Ref: whatsnew/3 9 new-modules877336
Ref: 8e6877336
Node: zoneinfo877409
Ref: whatsnew/3 9 zoneinfo877485
Ref: 8e7877485
Ref: zoneinfo-Footnote-1878592
Ref: zoneinfo-Footnote-2878633
Node: graphlib878675
Ref: whatsnew/3 9 graphlib878751
Ref: 8e9878751
Ref: graphlib-Footnote-1879075
Node: Improved Modules<5>879140
Ref: whatsnew/3 9 improved-modules879270
Ref: 8eb879270
Node: ast<2>880085
Ref: whatsnew/3 9 ast880166
Ref: 8ec880166
Ref: ast<2>-Footnote-1880828
Ref: ast<2>-Footnote-2880893
Ref: ast<2>-Footnote-3880958
Node: asyncio<5>881023
Ref: whatsnew/3 9 asyncio881126
Ref: 8ef881126
Ref: asyncio<5>-Footnote-1882841
Ref: asyncio<5>-Footnote-2882906
Ref: asyncio<5>-Footnote-3882971
Ref: asyncio<5>-Footnote-4883036
Ref: asyncio<5>-Footnote-5883101
Ref: asyncio<5>-Footnote-6883166
Node: compileall<2>883231
Ref: whatsnew/3 9 compileall883349
Ref: 8f4883349
Ref: compileall<2>-Footnote-1883939
Ref: compileall<2>-Footnote-2884004
Node: concurrent futures<2>884069
Ref: whatsnew/3 9 concurrent-futures884186
Ref: 8f5884186
Ref: concurrent futures<2>-Footnote-1885065
Ref: concurrent futures<2>-Footnote-2885130
Ref: concurrent futures<2>-Footnote-3885195
Node: curses<2>885260
Ref: whatsnew/3 9 curses885375
Ref: 8f8885375
Ref: curses<2>-Footnote-1885649
Node: datetime<2>885714
Ref: whatsnew/3 9 datetime885820
Ref: 8fd885820
Ref: datetime<2>-Footnote-1886138
Node: distutils<3>886203
Ref: whatsnew/3 9 distutils886308
Ref: 900886308
Ref: distutils<3>-Footnote-1886559
Node: fcntl<2>886624
Ref: whatsnew/3 9 fcntl886727
Ref: 901886727
Ref: fcntl<2>-Footnote-1886934
Node: ftplib<2>886999
Ref: whatsnew/3 9 ftplib887095
Ref: 902887095
Ref: ftplib<2>-Footnote-1887385
Node: gc<2>887450
Ref: whatsnew/3 9 gc887548
Ref: 905887548
Ref: gc<2>-Footnote-1888086
Ref: gc<2>-Footnote-2888151
Node: hashlib<4>888216
Ref: whatsnew/3 9 hashlib888309
Ref: 907888309
Ref: hashlib<4>-Footnote-1888818
Ref: hashlib<4>-Footnote-2888883
Node: http888948
Ref: whatsnew/3 9 http889055
Ref: 908889055
Ref: http-Footnote-1889327
Ref: http-Footnote-2889392
Node: IDLE and idlelib<3>889457
Ref: whatsnew/3 9 idle-and-idlelib889561
Ref: 90a889561
Ref: IDLE and idlelib<3>-Footnote-1890773
Ref: IDLE and idlelib<3>-Footnote-2890837
Ref: IDLE and idlelib<3>-Footnote-3890902
Ref: IDLE and idlelib<3>-Footnote-4890967
Ref: IDLE and idlelib<3>-Footnote-5891032
Ref: IDLE and idlelib<3>-Footnote-6891097
Ref: IDLE and idlelib<3>-Footnote-7891162
Node: imaplib891227
Ref: whatsnew/3 9 imaplib891339
Ref: 90b891339
Ref: imaplib-Footnote-1892162
Ref: imaplib-Footnote-2892227
Node: importlib<3>892292
Ref: whatsnew/3 9 importlib892395
Ref: 912892395
Ref: importlib<3>-Footnote-1893187
Ref: importlib<3>-Footnote-2893252
Ref: importlib<3>-Footnote-3893317
Node: inspect<4>893382
Ref: whatsnew/3 9 inspect893490
Ref: 914893490
Ref: inspect<4>-Footnote-1893722
Ref: inspect<4>-Footnote-2893787
Node: ipaddress<2>893852
Ref: whatsnew/3 9 ipaddress893955
Ref: 916893955
Ref: ipaddress<2>-Footnote-1894520
Ref: ipaddress<2>-Footnote-2894585
Node: math<4>894650
Ref: whatsnew/3 9 math894761
Ref: 918894761
Ref: math<4>-Footnote-1895477
Ref: math<4>-Footnote-2895542
Ref: math<4>-Footnote-3895607
Ref: math<4>-Footnote-4895672
Ref: math<4>-Footnote-5895737
Node: multiprocessing<2>895802
Ref: whatsnew/3 9 multiprocessing895908
Ref: 91c895908
Ref: multiprocessing<2>-Footnote-1896164
Node: nntplib896229
Ref: whatsnew/3 9 nntplib896333
Ref: 91f896333
Ref: nntplib-Footnote-1896617
Node: os<5>896682
Ref: whatsnew/3 9 os896778
Ref: 920896778
Ref: os<5>-Footnote-1897534
Ref: os<5>-Footnote-2897599
Ref: os<5>-Footnote-3897664
Ref: os<5>-Footnote-4897729
Ref: os<5>-Footnote-5897794
Ref: os<5>-Footnote-6897859
Node: pathlib<6>897924
Ref: whatsnew/3 9 pathlib898019
Ref: 927898019
Ref: pathlib<6>-Footnote-1898233
Node: pdb<3>898298
Ref: whatsnew/3 9 pdb898394
Ref: 92a898394
Ref: pdb<3>-Footnote-1898582
Node: poplib898647
Ref: whatsnew/3 9 poplib898742
Ref: 92c898742
Ref: poplib-Footnote-1899036
Node: pprint<2>899101
Ref: whatsnew/3 9 pprint899195
Ref: 92f899195
Ref: pprint<2>-Footnote-1899391
Node: pydoc899456
Ref: whatsnew/3 9 pydoc899553
Ref: 930899553
Ref: pydoc-Footnote-1899820
Node: random<3>899885
Ref: whatsnew/3 9 random899979
Ref: 932899979
Ref: random<3>-Footnote-1900180
Node: signal900245
Ref: whatsnew/3 9 signal900341
Ref: 934900341
Ref: signal-Footnote-1900571
Node: smtplib900636
Ref: whatsnew/3 9 smtplib900732
Ref: 936900732
Ref: smtplib-Footnote-1901144
Ref: smtplib-Footnote-2901209
Node: socket<3>901274
Ref: whatsnew/3 9 socket901371
Ref: 93a901371
Ref: socket<3>-Footnote-1901957
Ref: socket<3>-Footnote-2902022
Ref: socket<3>-Footnote-3902087
Node: time<3>902152
Ref: whatsnew/3 9 time902248
Ref: 93f902248
Ref: time<3>-Footnote-1902578
Node: sys<6>902643
Ref: whatsnew/3 9 sys902741
Ref: 941902741
Ref: sys<6>-Footnote-1903406
Ref: sys<6>-Footnote-2903473
Node: tracemalloc903538
Ref: whatsnew/3 9 tracemalloc903638
Ref: 944903638
Ref: tracemalloc-Footnote-1903922
Node: typing<6>903987
Ref: whatsnew/3 9 typing904095
Ref: 946904095
Ref: typing<6>-Footnote-1904451
Node: unicodedata<4>904493
Ref: whatsnew/3 9 unicodedata904597
Ref: 948904597
Ref: unicodedata<4>-Footnote-1904750
Node: venv<3>904815
Ref: whatsnew/3 9 venv904916
Ref: 949904916
Ref: venv<3>-Footnote-1905378
Node: xml<3>905443
Ref: whatsnew/3 9 xml905521
Ref: 94a905521
Ref: xml<3>-Footnote-1905883
Node: Optimizations<5>905948
Ref: whatsnew/3 9 optimizations906077
Ref: 94b906077
Ref: Optimizations<5>-Footnote-1911842
Ref: Optimizations<5>-Footnote-2911907
Ref: Optimizations<5>-Footnote-3911972
Ref: Optimizations<5>-Footnote-4912037
Ref: Optimizations<5>-Footnote-5912102
Ref: Optimizations<5>-Footnote-6912144
Ref: Optimizations<5>-Footnote-7912209
Ref: Optimizations<5>-Footnote-8912273
Ref: Optimizations<5>-Footnote-9912338
Ref: Optimizations<5>-Footnote-10912403
Ref: Optimizations<5>-Footnote-11912469
Ref: Optimizations<5>-Footnote-12912598
Node: Deprecated<7>912647
Ref: whatsnew/3 9 deprecated912767
Ref: 950912767
Ref: Deprecated<7>-Footnote-1917799
Ref: Deprecated<7>-Footnote-2917864
Ref: Deprecated<7>-Footnote-3917929
Ref: Deprecated<7>-Footnote-4917994
Ref: Deprecated<7>-Footnote-5918059
Ref: Deprecated<7>-Footnote-6918124
Ref: Deprecated<7>-Footnote-7918189
Ref: Deprecated<7>-Footnote-8918254
Ref: Deprecated<7>-Footnote-9918319
Ref: Deprecated<7>-Footnote-10918384
Ref: Deprecated<7>-Footnote-11918450
Ref: Deprecated<7>-Footnote-12918516
Ref: Deprecated<7>-Footnote-13918582
Ref: Deprecated<7>-Footnote-14918648
Ref: Deprecated<7>-Footnote-15918714
Ref: Deprecated<7>-Footnote-16918757
Ref: Deprecated<7>-Footnote-17918797
Ref: Deprecated<7>-Footnote-18918836
Ref: Deprecated<7>-Footnote-19918902
Node: Removed<7>918968
Ref: whatsnew/3 9 removed919093
Ref: 952919093
Ref: whatsnew/3 9 removed-in-python-39919093
Ref: 8d4919093
Ref: Removed<7>-Footnote-1925243
Ref: Removed<7>-Footnote-2925308
Ref: Removed<7>-Footnote-3925373
Ref: Removed<7>-Footnote-4925438
Ref: Removed<7>-Footnote-5925503
Ref: Removed<7>-Footnote-6925568
Ref: Removed<7>-Footnote-7925633
Ref: Removed<7>-Footnote-8925698
Ref: Removed<7>-Footnote-9925763
Ref: Removed<7>-Footnote-10925828
Ref: Removed<7>-Footnote-11925894
Ref: Removed<7>-Footnote-12925937
Ref: Removed<7>-Footnote-13926003
Ref: Removed<7>-Footnote-14926069
Ref: Removed<7>-Footnote-15926135
Ref: Removed<7>-Footnote-16926201
Ref: Removed<7>-Footnote-17926267
Ref: Removed<7>-Footnote-18926333
Ref: Removed<7>-Footnote-19926399
Ref: Removed<7>-Footnote-20926465
Ref: Removed<7>-Footnote-21926531
Ref: Removed<7>-Footnote-22926597
Node: Porting to Python 3 9926663
Ref: whatsnew/3 9 porting-to-python-3-9926791
Ref: 962926791
Node: Changes in the Python API<4>927132
Ref: whatsnew/3 9 changes-in-the-python-api927250
Ref: 963927250
Ref: Changes in the Python API<4>-Footnote-1931436
Ref: Changes in the Python API<4>-Footnote-2931501
Ref: Changes in the Python API<4>-Footnote-3931566
Ref: Changes in the Python API<4>-Footnote-4931631
Ref: Changes in the Python API<4>-Footnote-5931690
Ref: Changes in the Python API<4>-Footnote-6931755
Ref: Changes in the Python API<4>-Footnote-7931820
Ref: Changes in the Python API<4>-Footnote-8931885
Ref: Changes in the Python API<4>-Footnote-9931950
Ref: Changes in the Python API<4>-Footnote-10932015
Ref: Changes in the Python API<4>-Footnote-11932081
Node: Changes in the C API<3>932147
Ref: whatsnew/3 9 changes-in-the-c-api932301
Ref: 96e932301
Ref: Changes in the C API<3>-Footnote-1934425
Ref: Changes in the C API<3>-Footnote-2934490
Ref: Changes in the C API<3>-Footnote-3934555
Node: CPython bytecode changes<4>934620
Ref: whatsnew/3 9 cpython-bytecode-changes934737
Ref: 970934737
Ref: CPython bytecode changes<4>-Footnote-1935560
Ref: CPython bytecode changes<4>-Footnote-2935625
Node: Build Changes<5>935690
Ref: whatsnew/3 9 build-changes935824
Ref: 974935824
Ref: Build Changes<5>-Footnote-1938234
Ref: Build Changes<5>-Footnote-2938301
Ref: Build Changes<5>-Footnote-3938366
Ref: Build Changes<5>-Footnote-4938431
Ref: Build Changes<5>-Footnote-5938496
Ref: Build Changes<5>-Footnote-6938561
Ref: Build Changes<5>-Footnote-7938626
Ref: Build Changes<5>-Footnote-8938691
Node: C API Changes<5>938756
Ref: whatsnew/3 9 c-api-changes938900
Ref: 976938900
Node: New Features<10>939061
Ref: whatsnew/3 9 id1939163
Ref: 977939163
Ref: New Features<10>-Footnote-1942186
Ref: New Features<10>-Footnote-2942228
Ref: New Features<10>-Footnote-3942293
Ref: New Features<10>-Footnote-4942358
Ref: New Features<10>-Footnote-5942423
Ref: New Features<10>-Footnote-6942488
Ref: New Features<10>-Footnote-7942553
Ref: New Features<10>-Footnote-8942618
Ref: New Features<10>-Footnote-9942683
Ref: New Features<10>-Footnote-10942748
Ref: New Features<10>-Footnote-11942814
Ref: New Features<10>-Footnote-12942880
Node: Porting to Python 3 9<2>942946
Ref: whatsnew/3 9 id2943067
Ref: 983943067
Ref: Porting to Python 3 9<2>-Footnote-1946890
Ref: Porting to Python 3 9<2>-Footnote-2946932
Ref: Porting to Python 3 9<2>-Footnote-3946997
Ref: Porting to Python 3 9<2>-Footnote-4947062
Ref: Porting to Python 3 9<2>-Footnote-5947126
Ref: Porting to Python 3 9<2>-Footnote-6947191
Ref: Porting to Python 3 9<2>-Footnote-7947256
Ref: Porting to Python 3 9<2>-Footnote-8947298
Ref: Porting to Python 3 9<2>-Footnote-9947363
Ref: Porting to Python 3 9<2>-Footnote-10947428
Ref: Porting to Python 3 9<2>-Footnote-11947494
Node: Removed<8>947560
Ref: whatsnew/3 9 id3947656
Ref: 996947656
Ref: Removed<8>-Footnote-1951597
Ref: Removed<8>-Footnote-2951662
Ref: Removed<8>-Footnote-3951727
Ref: Removed<8>-Footnote-4951792
Ref: Removed<8>-Footnote-5951857
Ref: Removed<8>-Footnote-6951922
Ref: Removed<8>-Footnote-7951987
Ref: Removed<8>-Footnote-8952052
Ref: Removed<8>-Footnote-9952117
Ref: Removed<8>-Footnote-10952182
Ref: Removed<8>-Footnote-11952248
Ref: Removed<8>-Footnote-12952291
Ref: Removed<8>-Footnote-13952357
Node: Notable changes in Python 3 9 1952423
Ref: whatsnew/3 9 notable-changes-in-python-3-9-1952582
Ref: 999952582
Node: typing<7>952796
Ref: whatsnew/3 9 id4952930
Ref: 99a952930
Ref: typing<7>-Footnote-1954122
Ref: typing<7>-Footnote-2954164
Node: macOS 11 0 Big Sur and Apple Silicon Mac support954229
Ref: whatsnew/3 9 macos-11-0-big-sur-and-apple-silicon-mac-support954363
Ref: 99b954363
Ref: macOS 11 0 Big Sur and Apple Silicon Mac support-Footnote-1955173
Node: Notable changes in Python 3 9 2955238
Ref: whatsnew/3 9 notable-changes-in-python-3-9-2955412
Ref: 99c955412
Node: collections abc<2>955573
Ref: whatsnew/3 9 collections-abc955683
Ref: 99d955683
Ref: collections abc<2>-Footnote-1956644
Node: urllib parse<2>956709
Ref: whatsnew/3 9 urllib-parse956819
Ref: 99e956819
Ref: urllib parse<2>-Footnote-1957503
Node: Notable changes in Python 3 9 3957568
Ref: whatsnew/3 9 notable-changes-in-python-3-9-3957742
Ref: 99f957742
Ref: Notable changes in Python 3 9 3-Footnote-1958213
Node: Notable changes in Python 3 9 5958268
Ref: whatsnew/3 9 notable-changes-in-python-3-9-5958445
Ref: 9a0958445
Node: urllib parse<3>958567
Ref: whatsnew/3 9 id5958650
Ref: 9a1958650
Ref: urllib parse<3>-Footnote-1959179
Ref: urllib parse<3>-Footnote-2959238
Node: Notable security feature in 3 9 14959293
Ref: whatsnew/3 9 notable-security-feature-in-3-9-14959464
Ref: 9a2959464
Ref: Notable security feature in 3 9 14-Footnote-1960194
Node: Notable changes in 3 9 17960250
Ref: whatsnew/3 9 notable-changes-in-3-9-17960381
Ref: 9a3960381
Node: tarfile<4>960481
Ref: whatsnew/3 9 tarfile960553
Ref: 9a4960553
Ref: tarfile<4>-Footnote-1961157
Node: What’s New In Python 3 8961199
Ref: whatsnew/3 8 doc961354
Ref: 9a5961354
Ref: whatsnew/3 8 translation-repo961354
Ref: 9a6961354
Ref: whatsnew/3 8 what-s-new-in-python-3-8961354
Ref: 9a7961354
Node: Summary – Release highlights<5>962699
Ref: whatsnew/3 8 summary-release-highlights962820
Ref: 9a8962820
Node: New Features<11>962893
Ref: whatsnew/3 8 new-features963048
Ref: 9a9963048
Node: Assignment expressions963671
Ref: whatsnew/3 8 assignment-expressions963781
Ref: 9aa963781
Ref: Assignment expressions-Footnote-1965287
Ref: Assignment expressions-Footnote-2965384
Ref: Assignment expressions-Footnote-3965426
Node: Positional-only parameters965491
Ref: whatsnew/3 8 positional-only-parameters965663
Ref: 9ab965663
Ref: Positional-only parameters-Footnote-1968345
Ref: Positional-only parameters-Footnote-2968407
Ref: Positional-only parameters-Footnote-3968449
Node: Parallel filesystem cache for compiled bytecode files968514
Ref: whatsnew/3 8 parallel-filesystem-cache-for-compiled-bytecode-files968710
Ref: 9ad968710
Ref: Parallel filesystem cache for compiled bytecode files-Footnote-1969352
Node: Debug build uses the same ABI as release build969417
Ref: whatsnew/3 8 debug-build-uses-the-same-abi-as-release-build969653
Ref: 9b0969653
Ref: Debug build uses the same ABI as release build-Footnote-1972055
Ref: Debug build uses the same ABI as release build-Footnote-2972120
Ref: Debug build uses the same ABI as release build-Footnote-3972185
Ref: Debug build uses the same ABI as release build-Footnote-4972250
Node: f-strings support = for self-documenting expressions and debugging972315
Ref: whatsnew/3 8 bpo-36817-whatsnew972532
Ref: 9b2972532
Ref: whatsnew/3 8 f-strings-support-for-self-documenting-expressions-and-debugging972532
Ref: 9b3972532
Ref: f-strings support = for self-documenting expressions and debugging-Footnote-1973658
Node: PEP 578 Python Runtime Audit Hooks973723
Ref: whatsnew/3 8 pep-578-python-runtime-audit-hooks973937
Ref: 9b5973937
Ref: PEP 578 Python Runtime Audit Hooks-Footnote-1974420
Node: PEP 587 Python Initialization Configuration974462
Ref: whatsnew/3 8 pep-587-python-initialization-configuration974664
Ref: 9b6974664
Ref: PEP 587 Python Initialization Configuration-Footnote-1976651
Ref: PEP 587 Python Initialization Configuration-Footnote-2976693
Ref: PEP 587 Python Initialization Configuration-Footnote-3976735
Node: PEP 590 Vectorcall a fast calling protocol for CPython976800
Ref: whatsnew/3 8 pep-590-vectorcall-a-fast-calling-protocol-for-cpython977015
Ref: 9d1977015
Ref: PEP 590 Vectorcall a fast calling protocol for CPython-Footnote-1977623
Ref: PEP 590 Vectorcall a fast calling protocol for CPython-Footnote-2977665
Node: Pickle protocol 5 with out-of-band data buffers977730
Ref: whatsnew/3 8 pickle-protocol-5-with-out-of-band-data-buffers977893
Ref: 9d2977893
Ref: Pickle protocol 5 with out-of-band data buffers-Footnote-1978645
Ref: Pickle protocol 5 with out-of-band data buffers-Footnote-2978687
Ref: Pickle protocol 5 with out-of-band data buffers-Footnote-3978729
Node: Other Language Changes<6>978794
Ref: whatsnew/3 8 other-language-changes978930
Ref: 9d3978930
Ref: Other Language Changes<6>-Footnote-1986302
Ref: Other Language Changes<6>-Footnote-2986367
Ref: Other Language Changes<6>-Footnote-3986432
Ref: Other Language Changes<6>-Footnote-4986497
Ref: Other Language Changes<6>-Footnote-5986562
Ref: Other Language Changes<6>-Footnote-6986627
Ref: Other Language Changes<6>-Footnote-7986692
Ref: Other Language Changes<6>-Footnote-8986757
Ref: Other Language Changes<6>-Footnote-9986822
Ref: Other Language Changes<6>-Footnote-10986887
Ref: Other Language Changes<6>-Footnote-11986953
Ref: Other Language Changes<6>-Footnote-12987021
Ref: Other Language Changes<6>-Footnote-13987087
Ref: Other Language Changes<6>-Footnote-14987157
Ref: Other Language Changes<6>-Footnote-15987217
Ref: Other Language Changes<6>-Footnote-16987283
Ref: Other Language Changes<6>-Footnote-17987349
Node: New Modules<6>987415
Ref: whatsnew/3 8 new-modules987554
Ref: 9e0987554
Ref: New Modules<6>-Footnote-1988632
Node: Improved Modules<6>988697
Ref: whatsnew/3 8 improved-modules988827
Ref: 9e1988827
Node: ast<3>989842
Ref: whatsnew/3 8 ast989923
Ref: 9e2989923
Ref: ast<3>-Footnote-1990955
Ref: ast<3>-Footnote-2991020
Ref: ast<3>-Footnote-3991062
Ref: ast<3>-Footnote-4991104
Ref: ast<3>-Footnote-5991146
Node: asyncio<6>991211
Ref: whatsnew/3 8 asyncio991312
Ref: 9e4991312
Ref: asyncio<6>-Footnote-1994468
Ref: asyncio<6>-Footnote-2994533
Ref: asyncio<6>-Footnote-3994598
Ref: asyncio<6>-Footnote-4994663
Ref: asyncio<6>-Footnote-5994728
Ref: asyncio<6>-Footnote-6994793
Ref: asyncio<6>-Footnote-7994858
Ref: asyncio<6>-Footnote-8994923
Ref: asyncio<6>-Footnote-9994988
Ref: asyncio<6>-Footnote-10995041
Node: builtins<2>995107
Ref: whatsnew/3 8 builtins995213
Ref: 9ea995213
Ref: builtins<2>-Footnote-1995706
Node: collections995771
Ref: whatsnew/3 8 collections995875
Ref: 9eb995875
Ref: collections-Footnote-1996397
Node: cProfile996462
Ref: whatsnew/3 8 cprofile996561
Ref: 9ed996561
Ref: cProfile-Footnote-1996911
Node: csv<2>996976
Ref: whatsnew/3 8 csv997073
Ref: 9ef997073
Ref: csv<2>-Footnote-1997390
Node: curses<3>997455
Ref: whatsnew/3 8 curses997553
Ref: 9f1997553
Ref: curses<3>-Footnote-1997797
Node: ctypes<2>997862
Ref: whatsnew/3 8 ctypes997965
Ref: 9f3997965
Ref: ctypes<2>-Footnote-1998454
Node: datetime<3>998519
Ref: whatsnew/3 8 datetime998625
Ref: 9f6998625
Ref: datetime<3>-Footnote-1999060
Node: functools<2>999125
Ref: whatsnew/3 8 functools999227
Ref: 9f9999227
Ref: functools<2>-Footnote-11000769
Ref: functools<2>-Footnote-21000834
Ref: functools<2>-Footnote-31000899
Node: gc<3>1000964
Ref: whatsnew/3 8 gc1001062
Ref: 9fe1001062
Ref: gc<3>-Footnote-11001295
Node: gettext1001360
Ref: whatsnew/3 8 gettext1001453
Ref: 9ff1001453
Ref: gettext-Footnote-11001654
Node: gzip<3>1001718
Ref: whatsnew/3 8 gzip1001825
Ref: a011001825
Ref: gzip<3>-Footnote-11002242
Ref: gzip<3>-Footnote-21002307
Node: IDLE and idlelib<4>1002371
Ref: whatsnew/3 8 idle-and-idlelib1002481
Ref: a031002481
Ref: IDLE and idlelib<4>-Footnote-11004450
Ref: IDLE and idlelib<4>-Footnote-21004517
Ref: IDLE and idlelib<4>-Footnote-31004581
Ref: IDLE and idlelib<4>-Footnote-41004646
Ref: IDLE and idlelib<4>-Footnote-51004711
Ref: IDLE and idlelib<4>-Footnote-61004776
Ref: IDLE and idlelib<4>-Footnote-71004840
Ref: IDLE and idlelib<4>-Footnote-81004905
Node: inspect<5>1004970
Ref: whatsnew/3 8 inspect1005078
Ref: a041005078
Ref: inspect<5>-Footnote-11005844
Node: io<3>1005909
Ref: whatsnew/3 8 io1006010
Ref: a061006010
Ref: io<3>-Footnote-11006358
Node: itertools<4>1006423
Ref: whatsnew/3 8 itertools1006523
Ref: a071006523
Ref: itertools<4>-Footnote-11006901
Node: json tool1006966
Ref: whatsnew/3 8 json-tool1007071
Ref: a091007071
Ref: json tool-Footnote-11007278
Node: logging<2>1007343
Ref: whatsnew/3 8 logging1007443
Ref: a0a1007443
Ref: logging<2>-Footnote-11008158
Node: math<5>1008223
Ref: whatsnew/3 8 math1008321
Ref: a0c1008321
Ref: math<5>-Footnote-11010070
Ref: math<5>-Footnote-21010135
Ref: math<5>-Footnote-31010200
Ref: math<5>-Footnote-41010265
Ref: math<5>-Footnote-51010330
Ref: math<5>-Footnote-61010395
Ref: math<5>-Footnote-71010460
Ref: math<5>-Footnote-81010525
Node: mmap<2>1010590
Ref: whatsnew/3 8 mmap1010696
Ref: a121010696
Ref: mmap<2>-Footnote-11010926
Node: multiprocessing<3>1010991
Ref: whatsnew/3 8 multiprocessing1011095
Ref: a141011095
Ref: multiprocessing<3>-Footnote-11011399
Ref: multiprocessing<3>-Footnote-21011464
Node: os<6>1011529
Ref: whatsnew/3 8 os1011636
Ref: a151011636
Ref: os<6>-Footnote-11013151
Ref: os<6>-Footnote-21013216
Ref: os<6>-Footnote-31013281
Node: os path<5>1013346
Ref: whatsnew/3 8 os-path1013445
Ref: a1a1013445
Ref: os path<5>-Footnote-11014468
Ref: os path<5>-Footnote-21014533
Ref: os path<5>-Footnote-31014598
Node: pathlib<7>1014663
Ref: whatsnew/3 8 pathlib1014763
Ref: a221014763
Ref: pathlib<7>-Footnote-11015672
Ref: pathlib<7>-Footnote-21015737
Node: pickle1015802
Ref: whatsnew/3 8 pickle1015900
Ref: a2a1015900
Ref: pickle-Footnote-11016238
Node: plistlib1016303
Ref: whatsnew/3 8 plistlib1016400
Ref: a2d1016400
Ref: plistlib-Footnote-11016638
Node: pprint<3>1016703
Ref: whatsnew/3 8 pprint1016807
Ref: a2f1016807
Ref: pprint<3>-Footnote-11017872
Node: py_compile<2>1017937
Ref: whatsnew/3 8 py-compile1018038
Ref: a311018038
Ref: py_compile<2>-Footnote-11018227
Node: shlex1018292
Ref: whatsnew/3 8 shlex1018393
Ref: a331018393
Ref: shlex-Footnote-11018597
Node: shutil<4>1018662
Ref: whatsnew/3 8 shutil1018759
Ref: a351018759
Ref: shutil<4>-Footnote-11019412
Ref: shutil<4>-Footnote-21019477
Ref: shutil<4>-Footnote-31019542
Node: socket<4>1019607
Ref: whatsnew/3 8 socket1019705
Ref: a371019705
Ref: socket<4>-Footnote-11020280
Ref: socket<4>-Footnote-21020345
Node: ssl<4>1020410
Ref: whatsnew/3 8 ssl1020512
Ref: a3d1020512
Ref: ssl<4>-Footnote-11020774
Node: statistics<4>1020839
Ref: whatsnew/3 8 statistics1020938
Ref: a401020938
Ref: statistics<4>-Footnote-11022669
Ref: statistics<4>-Footnote-21022734
Ref: statistics<4>-Footnote-31022799
Ref: statistics<4>-Footnote-41022864
Ref: statistics<4>-Footnote-51022929
Node: sys<7>1022994
Ref: whatsnew/3 8 sys1023097
Ref: a461023097
Ref: sys<7>-Footnote-11023540
Node: tarfile<5>1023605
Ref: whatsnew/3 8 tarfile1023707
Ref: a481023707
Ref: tarfile<5>-Footnote-11024125
Node: threading<4>1024190
Ref: whatsnew/3 8 threading1024297
Ref: a491024297
Ref: threading<4>-Footnote-11025022
Ref: threading<4>-Footnote-21025089
Node: tokenize<2>1025154
Ref: whatsnew/3 8 tokenize1025261
Ref: a4d1025261
Ref: tokenize<2>-Footnote-11025586
Node: tkinter<4>1025651
Ref: whatsnew/3 8 tkinter1025753
Ref: a4e1025753
Ref: tkinter<4>-Footnote-11026296
Ref: tkinter<4>-Footnote-21026361
Ref: tkinter<4>-Footnote-31026426
Node: time<4>1026491
Ref: whatsnew/3 8 time1026591
Ref: a4f1026591
Ref: time<4>-Footnote-11026770
Node: typing<8>1026835
Ref: whatsnew/3 8 typing1026939
Ref: a511026939
Ref: typing<8>-Footnote-11028413
Ref: typing<8>-Footnote-21028455
Ref: typing<8>-Footnote-31028497
Ref: typing<8>-Footnote-41028539
Node: unicodedata<5>1028581
Ref: whatsnew/3 8 unicodedata1028689
Ref: a541028689
Ref: unicodedata<5>-Footnote-11029118
Ref: unicodedata<5>-Footnote-21029180
Ref: unicodedata<5>-Footnote-31029245
Node: unittest<6>1029310
Ref: whatsnew/3 8 unittest1029416
Ref: a561029416
Ref: unittest<6>-Footnote-11030712
Ref: unittest<6>-Footnote-21030777
Ref: unittest<6>-Footnote-31030842
Ref: unittest<6>-Footnote-41030907
Node: venv<4>1030972
Ref: whatsnew/3 8 venv1031071
Ref: a5d1031071
Ref: venv<4>-Footnote-11031323
Node: weakref1031388
Ref: whatsnew/3 8 weakref1031482
Ref: a5e1031482
Ref: weakref-Footnote-11031775
Node: xml<4>1031840
Ref: whatsnew/3 8 xml1031933
Ref: a601031933
Ref: xml<4>-Footnote-11033089
Ref: xml<4>-Footnote-21033154
Ref: xml<4>-Footnote-31033219
Ref: xml<4>-Footnote-41033284
Ref: xml<4>-Footnote-51033349
Node: xmlrpc1033414
Ref: whatsnew/3 8 xmlrpc1033491
Ref: a641033491
Ref: xmlrpc-Footnote-11033883
Node: Optimizations<6>1033948
Ref: whatsnew/3 8 optimizations1034087
Ref: a661034087
Ref: Optimizations<6>-Footnote-11038442
Ref: Optimizations<6>-Footnote-21038507
Ref: Optimizations<6>-Footnote-31038572
Ref: Optimizations<6>-Footnote-41038637
Ref: Optimizations<6>-Footnote-51038702
Ref: Optimizations<6>-Footnote-61038767
Ref: Optimizations<6>-Footnote-71038832
Ref: Optimizations<6>-Footnote-81038897
Ref: Optimizations<6>-Footnote-91038962
Ref: Optimizations<6>-Footnote-101039027
Ref: Optimizations<6>-Footnote-111039093
Ref: Optimizations<6>-Footnote-121039159
Ref: Optimizations<6>-Footnote-131039225
Node: Build and C API Changes1039291
Ref: whatsnew/3 8 build-and-c-api-changes1039424
Ref: a711039424
Ref: Build and C API Changes-Footnote-11045001
Ref: Build and C API Changes-Footnote-21045066
Ref: Build and C API Changes-Footnote-31045131
Ref: Build and C API Changes-Footnote-41045196
Ref: Build and C API Changes-Footnote-51045261
Ref: Build and C API Changes-Footnote-61045326
Ref: Build and C API Changes-Footnote-71045391
Ref: Build and C API Changes-Footnote-81045456
Ref: Build and C API Changes-Footnote-91045521
Ref: Build and C API Changes-Footnote-101045586
Ref: Build and C API Changes-Footnote-111045652
Ref: Build and C API Changes-Footnote-121045718
Node: Deprecated<8>1045784
Ref: whatsnew/3 8 deprecated1045925
Ref: a7b1045925
Ref: Deprecated<8>-Footnote-11051791
Ref: Deprecated<8>-Footnote-21051856
Ref: Deprecated<8>-Footnote-31051921
Ref: Deprecated<8>-Footnote-41051986
Ref: Deprecated<8>-Footnote-51052050
Ref: Deprecated<8>-Footnote-61052115
Ref: Deprecated<8>-Footnote-71052180
Ref: Deprecated<8>-Footnote-81052245
Ref: Deprecated<8>-Footnote-91052310
Ref: Deprecated<8>-Footnote-101052375
Ref: Deprecated<8>-Footnote-111052441
Ref: Deprecated<8>-Footnote-121052507
Ref: Deprecated<8>-Footnote-131052573
Node: API and Feature Removals1052639
Ref: whatsnew/3 8 api-and-feature-removals1052778
Ref: a951052778
Ref: API and Feature Removals-Footnote-11055600
Ref: API and Feature Removals-Footnote-21055655
Ref: API and Feature Removals-Footnote-31055720
Ref: API and Feature Removals-Footnote-41055785
Ref: API and Feature Removals-Footnote-51055850
Ref: API and Feature Removals-Footnote-61055915
Ref: API and Feature Removals-Footnote-71055980
Ref: API and Feature Removals-Footnote-81056045
Ref: API and Feature Removals-Footnote-91056110
Ref: API and Feature Removals-Footnote-101056175
Ref: API and Feature Removals-Footnote-111056241
Node: Porting to Python 3 81056307
Ref: whatsnew/3 8 porting-to-python-3-81056464
Ref: a991056464
Node: Changes in Python behavior1056875
Ref: whatsnew/3 8 changes-in-python-behavior1056996
Ref: a9a1056996
Ref: Changes in Python behavior-Footnote-11059363
Ref: Changes in Python behavior-Footnote-21059428
Ref: Changes in Python behavior-Footnote-31059493
Ref: Changes in Python behavior-Footnote-41059558
Ref: Changes in Python behavior-Footnote-51059623
Ref: Changes in Python behavior-Footnote-61059688
Node: Changes in the Python API<5>1059753
Ref: whatsnew/3 8 changes-in-the-python-api1059906
Ref: a9f1059906
Ref: whatsnew/3 8 bpo-36085-whatsnew1066943
Ref: ab31066943
Ref: Changes in the Python API<5>-Footnote-11068591
Ref: Changes in the Python API<5>-Footnote-21068633
Ref: Changes in the Python API<5>-Footnote-31068698
Ref: Changes in the Python API<5>-Footnote-41068763
Ref: Changes in the Python API<5>-Footnote-51068828
Ref: Changes in the Python API<5>-Footnote-61068893
Ref: Changes in the Python API<5>-Footnote-71068958
Ref: Changes in the Python API<5>-Footnote-81069023
Ref: Changes in the Python API<5>-Footnote-91069088
Ref: Changes in the Python API<5>-Footnote-101069153
Ref: Changes in the Python API<5>-Footnote-111069219
Ref: Changes in the Python API<5>-Footnote-121069285
Ref: Changes in the Python API<5>-Footnote-131069351
Ref: Changes in the Python API<5>-Footnote-141069417
Ref: Changes in the Python API<5>-Footnote-151069483
Ref: Changes in the Python API<5>-Footnote-161069549
Ref: Changes in the Python API<5>-Footnote-171069615
Ref: Changes in the Python API<5>-Footnote-181069680
Ref: Changes in the Python API<5>-Footnote-191069746
Ref: Changes in the Python API<5>-Footnote-201069812
Ref: Changes in the Python API<5>-Footnote-211069878
Ref: Changes in the Python API<5>-Footnote-221069944
Ref: Changes in the Python API<5>-Footnote-231070010
Ref: Changes in the Python API<5>-Footnote-241070076
Ref: Changes in the Python API<5>-Footnote-251070142
Ref: Changes in the Python API<5>-Footnote-261070208
Ref: Changes in the Python API<5>-Footnote-271070274
Node: Changes in the C API<4>1070317
Ref: whatsnew/3 8 changes-in-the-c-api1070471
Ref: ab51070471
Ref: Changes in the C API<4>-Footnote-11076297
Ref: Changes in the C API<4>-Footnote-21076362
Ref: Changes in the C API<4>-Footnote-31076427
Ref: Changes in the C API<4>-Footnote-41076492
Ref: Changes in the C API<4>-Footnote-51076557
Ref: Changes in the C API<4>-Footnote-61076622
Ref: Changes in the C API<4>-Footnote-71076687
Ref: Changes in the C API<4>-Footnote-81076752
Node: CPython bytecode changes<5>1076817
Ref: whatsnew/3 8 cpython-bytecode-changes1076961
Ref: abd1076961
Ref: CPython bytecode changes<5>-Footnote-11078286
Ref: CPython bytecode changes<5>-Footnote-21078351
Ref: CPython bytecode changes<5>-Footnote-31078416
Ref: CPython bytecode changes<5>-Footnote-41078458
Node: Demos and Tools<2>1078523
Ref: whatsnew/3 8 demos-and-tools1078635
Ref: ac21078635
Ref: Demos and Tools<2>-Footnote-11081932
Ref: Demos and Tools<2>-Footnote-21081997
Ref: Demos and Tools<2>-Footnote-31082125
Node: Notable changes in Python 3 8 11082173
Ref: whatsnew/3 8 notable-changes-in-python-3-8-11082337
Ref: ac31082337
Ref: Notable changes in Python 3 8 1-Footnote-11082848
Node: Notable changes in Python 3 8 21082913
Ref: whatsnew/3 8 notable-changes-in-python-3-8-21083087
Ref: ac41083087
Ref: Notable changes in Python 3 8 2-Footnote-11083409
Node: Notable changes in Python 3 8 31083464
Ref: whatsnew/3 8 notable-changes-in-python-3-8-31083638
Ref: ac51083638
Ref: Notable changes in Python 3 8 3-Footnote-11084025
Node: Notable changes in Python 3 8 81084080
Ref: whatsnew/3 8 notable-changes-in-python-3-8-81084254
Ref: ac61084254
Ref: Notable changes in Python 3 8 8-Footnote-11084972
Node: Notable changes in Python 3 8 91085037
Ref: whatsnew/3 8 notable-changes-in-python-3-8-91085212
Ref: ac71085212
Ref: Notable changes in Python 3 8 9-Footnote-11085683
Node: Notable changes in Python 3 8 101085738
Ref: whatsnew/3 8 notable-changes-in-python-3-8-101085917
Ref: ac81085917
Node: macOS 11 0 Big Sur and Apple Silicon Mac support<2>1086115
Ref: whatsnew/3 8 macos-11-0-big-sur-and-apple-silicon-mac-support1086235
Ref: ac91086235
Ref: macOS 11 0 Big Sur and Apple Silicon Mac support<2>-Footnote-11087212
Node: Notable changes in Python 3 8 10<2>1087267
Ref: whatsnew/3 8 id11087447
Ref: aca1087447
Node: urllib parse<4>1087571
Ref: whatsnew/3 8 urllib-parse1087658
Ref: acb1087658
Ref: urllib parse<4>-Footnote-11088188
Ref: urllib parse<4>-Footnote-21088247
Node: Notable changes in Python 3 8 121088312
Ref: whatsnew/3 8 notable-changes-in-python-3-8-121088494
Ref: acc1088494
Node: Changes in the Python API<6>1088644
Ref: whatsnew/3 8 id21088741
Ref: acd1088741
Ref: Changes in the Python API<6>-Footnote-11089352
Node: Notable security feature in 3 8 141089417
Ref: whatsnew/3 8 notable-security-feature-in-3-8-141089589
Ref: ace1089589
Ref: Notable security feature in 3 8 14-Footnote-11090319
Node: Notable changes in 3 8 171090375
Ref: whatsnew/3 8 notable-changes-in-3-8-171090506
Ref: acf1090506
Node: tarfile<6>1090606
Ref: whatsnew/3 8 id31090678
Ref: ad01090678
Ref: tarfile<6>-Footnote-11091282
Node: What’s New In Python 3 71091324
Ref: whatsnew/3 7 doc1091479
Ref: ad11091479
Ref: whatsnew/3 7 translation-repo1091479
Ref: ad21091479
Ref: whatsnew/3 7 what-s-new-in-python-3-71091479
Ref: ad31091479
Node: Summary – Release Highlights<2>1092954
Ref: whatsnew/3 7 summary-release-highlights1093075
Ref: ad41093075
Ref: Summary – Release Highlights<2>-Footnote-11095222
Ref: Summary – Release Highlights<2>-Footnote-21095302
Ref: Summary – Release Highlights<2>-Footnote-31095338
Ref: Summary – Release Highlights<2>-Footnote-41095374
Node: New Features<12>1095410
Ref: whatsnew/3 7 new-features1095565
Ref: ae81095565
Node: PEP 563 Postponed Evaluation of Annotations1096662
Ref: whatsnew/3 7 pep-563-postponed-evaluation-of-annotations1096799
Ref: ae91096799
Ref: whatsnew/3 7 whatsnew37-pep5631096799
Ref: ad51096799
Ref: PEP 563 Postponed Evaluation of Annotations-Footnote-11098563
Ref: PEP 563 Postponed Evaluation of Annotations-Footnote-21098605
Ref: PEP 563 Postponed Evaluation of Annotations-Footnote-31098647
Node: PEP 538 Legacy C Locale Coercion1098689
Ref: whatsnew/3 7 pep-538-legacy-c-locale-coercion1098868
Ref: aea1098868
Ref: whatsnew/3 7 whatsnew37-pep5381098868
Ref: adf1098868
Ref: PEP 538 Legacy C Locale Coercion-Footnote-11101255
Ref: PEP 538 Legacy C Locale Coercion-Footnote-21101297
Ref: PEP 538 Legacy C Locale Coercion-Footnote-31101339
Ref: PEP 538 Legacy C Locale Coercion-Footnote-41101381
Node: PEP 540 Forced UTF-8 Runtime Mode1101423
Ref: whatsnew/3 7 pep-540-forced-utf-8-runtime-mode1101586
Ref: aed1101586
Ref: whatsnew/3 7 whatsnew37-pep5401101586
Ref: ae01101586
Ref: PEP 540 Forced UTF-8 Runtime Mode-Footnote-11103150
Ref: PEP 540 Forced UTF-8 Runtime Mode-Footnote-21103192
Ref: PEP 540 Forced UTF-8 Runtime Mode-Footnote-31103234
Node: PEP 553 Built-in breakpoint1103276
Ref: whatsnew/3 7 pep-553-built-in-breakpoint1103449
Ref: aef1103449
Ref: whatsnew/3 7 whatsnew37-pep5531103449
Ref: ad91103449
Ref: PEP 553 Built-in breakpoint-Footnote-11104288
Node: PEP 539 New C API for Thread-Local Storage1104330
Ref: whatsnew/3 7 pep-539-new-c-api-for-thread-local-storage1104522
Ref: af21104522
Ref: whatsnew/3 7 whatsnew37-pep5391104522
Ref: ae41104522
Ref: PEP 539 New C API for Thread-Local Storage-Footnote-11106017
Ref: PEP 539 New C API for Thread-Local Storage-Footnote-21106059
Node: PEP 562 Customization of Access to Module Attributes1106101
Ref: whatsnew/3 7 pep-562-customization-of-access-to-module-attributes1106319
Ref: af61106319
Ref: whatsnew/3 7 whatsnew37-pep5621106319
Ref: ada1106319
Ref: PEP 562 Customization of Access to Module Attributes-Footnote-11106906
Node: PEP 564 New Time Functions With Nanosecond Resolution1106948
Ref: whatsnew/3 7 pep-564-new-time-functions-with-nanosecond-resolution1107167
Ref: af91107167
Ref: whatsnew/3 7 whatsnew37-pep5641107167
Ref: ade1107167
Ref: PEP 564 New Time Functions With Nanosecond Resolution-Footnote-11108252
Ref: PEP 564 New Time Functions With Nanosecond Resolution-Footnote-21108294
Ref: PEP 564 New Time Functions With Nanosecond Resolution-Footnote-31108371
Node: PEP 565 Show DeprecationWarning in __main__1108413
Ref: whatsnew/3 7 pep-565-show-deprecationwarning-in-main1108636
Ref: b001108636
Ref: whatsnew/3 7 whatsnew37-pep5651108636
Ref: ae31108636
Ref: PEP 565 Show DeprecationWarning in __main__-Footnote-11110568
Node: PEP 560 Core Support for typing module and Generic Types1110610
Ref: whatsnew/3 7 pep-560-core-support-for-typing-module-and-generic-types1110808
Ref: b011110808
Ref: whatsnew/3 7 whatsnew37-pep5601110808
Ref: adb1110808
Ref: PEP 560 Core Support for typing module and Generic Types-Footnote-11111759
Ref: PEP 560 Core Support for typing module and Generic Types-Footnote-21111801
Node: PEP 552 Hash-based pyc Files1111843
Ref: whatsnew/3 7 pep-552-hash-based-pyc-files1112039
Ref: b031112039
Ref: whatsnew/3 7 whatsnew37-pep5521112039
Ref: ae11112039
Ref: PEP 552 Hash-based pyc Files-Footnote-11113713
Ref: PEP 552 Hash-based pyc Files-Footnote-21113754
Ref: PEP 552 Hash-based pyc Files-Footnote-31113796
Node: PEP 545 Python Documentation Translations1113838
Ref: whatsnew/3 7 pep-545-python-documentation-translations1114008
Ref: b041114008
Ref: whatsnew/3 7 whatsnew37-pep5451114008
Ref: ae51114008
Ref: PEP 545 Python Documentation Translations-Footnote-11114592
Ref: PEP 545 Python Documentation Translations-Footnote-21114634
Node: Python Development Mode -X dev1114676
Ref: whatsnew/3 7 python-development-mode-x-dev1114809
Ref: b051114809
Ref: whatsnew/3 7 whatsnew37-devmode1114809
Ref: ae21114809
Node: Other Language Changes<7>1115263
Ref: whatsnew/3 7 other-language-changes1115399
Ref: b071115399
Ref: Other Language Changes<7>-Footnote-11117791
Ref: Other Language Changes<7>-Footnote-21117856
Ref: Other Language Changes<7>-Footnote-31117921
Ref: Other Language Changes<7>-Footnote-41117986
Ref: Other Language Changes<7>-Footnote-51118051
Ref: Other Language Changes<7>-Footnote-61118116
Ref: Other Language Changes<7>-Footnote-71118181
Ref: Other Language Changes<7>-Footnote-81118246
Ref: Other Language Changes<7>-Footnote-91118311
Ref: Other Language Changes<7>-Footnote-101118376
Node: New Modules<7>1118442
Ref: whatsnew/3 7 new-modules1118581
Ref: b0f1118581
Node: contextvars1118722
Ref: whatsnew/3 7 contextvars1118807
Ref: b101118807
Ref: whatsnew/3 7 whatsnew37-pep5671118807
Ref: ad61118807
Ref: contextvars-Footnote-11119536
Node: dataclasses<3>1119578
Ref: whatsnew/3 7 dataclasses1119694
Ref: b121119694
Ref: whatsnew/3 7 whatsnew37-pep5571119694
Ref: ad71119694
Ref: dataclasses<3>-Footnote-11120365
Node: importlib resources<2>1120407
Ref: whatsnew/3 7 importlib-resources1120503
Ref: b151120503
Ref: whatsnew/3 7 whatsnew37-importlib-resources1120503
Ref: ad81120503
Ref: importlib resources<2>-Footnote-11121251
Ref: importlib resources<2>-Footnote-21121316
Node: Improved Modules<7>1121378
Ref: whatsnew/3 7 improved-modules1121508
Ref: b171121508
Node: argparse<3>1122955
Ref: whatsnew/3 7 argparse1123041
Ref: b181123041
Ref: argparse<3>-Footnote-11123275
Node: asyncio<7>1123340
Ref: whatsnew/3 7 asyncio1123443
Ref: b1a1123443
Ref: whatsnew/3 7 whatsnew37-asyncio1123443
Ref: add1123443
Ref: asyncio<7>-Footnote-11129728
Ref: asyncio<7>-Footnote-21129793
Ref: asyncio<7>-Footnote-31129835
Ref: asyncio<7>-Footnote-41129900
Ref: asyncio<7>-Footnote-51129965
Ref: asyncio<7>-Footnote-61130030
Ref: asyncio<7>-Footnote-71130095
Ref: asyncio<7>-Footnote-81130160
Ref: asyncio<7>-Footnote-91130225
Ref: asyncio<7>-Footnote-101130290
Ref: asyncio<7>-Footnote-111130356
Ref: asyncio<7>-Footnote-121130422
Ref: asyncio<7>-Footnote-131130488
Ref: asyncio<7>-Footnote-141130554
Ref: asyncio<7>-Footnote-151130620
Ref: asyncio<7>-Footnote-161130686
Ref: asyncio<7>-Footnote-171130752
Ref: asyncio<7>-Footnote-181130818
Ref: asyncio<7>-Footnote-191130884
Ref: asyncio<7>-Footnote-201130950
Ref: asyncio<7>-Footnote-211131016
Ref: asyncio<7>-Footnote-221131082
Ref: asyncio<7>-Footnote-231131148
Ref: asyncio<7>-Footnote-241131214
Node: binascii1131280
Ref: whatsnew/3 7 binascii1131383
Ref: b381131383
Ref: binascii-Footnote-11131662
Node: calendar<2>1131727
Ref: whatsnew/3 7 calendar1131834
Ref: b3a1131834
Ref: calendar<2>-Footnote-11132084
Node: collections<2>1132149
Ref: whatsnew/3 7 collections1132261
Ref: b3c1132261
Ref: collections<2>-Footnote-11132452
Node: compileall<3>1132517
Ref: whatsnew/3 7 compileall1132639
Ref: b3d1132639
Ref: compileall<3>-Footnote-11133036
Node: concurrent futures<3>1133101
Ref: whatsnew/3 7 concurrent-futures1133222
Ref: b3f1133222
Ref: concurrent futures<3>-Footnote-11133664
Ref: concurrent futures<3>-Footnote-21133729
Node: contextlib<3>1133794
Ref: whatsnew/3 7 contextlib1133913
Ref: b401133913
Ref: contextlib<3>-Footnote-11134443
Ref: contextlib<3>-Footnote-21134508
Ref: contextlib<3>-Footnote-31134573
Ref: contextlib<3>-Footnote-41134638
Node: cProfile<2>1134703
Ref: whatsnew/3 7 cprofile1134806
Ref: b451134806
Ref: cProfile<2>-Footnote-11135032
Node: crypt1135097
Ref: whatsnew/3 7 crypt1135198
Ref: b461135198
Ref: crypt-Footnote-11135519
Ref: crypt-Footnote-21135584
Node: datetime<4>1135649
Ref: whatsnew/3 7 datetime1135745
Ref: b471135745
Ref: datetime<4>-Footnote-11136156
Ref: datetime<4>-Footnote-21136221
Node: dbm<2>1136285
Ref: whatsnew/3 7 dbm1136383
Ref: b491136383
Node: decimal1136528
Ref: whatsnew/3 7 decimal1136621
Ref: b4a1136621
Ref: decimal-Footnote-11136842
Node: dis<3>1136907
Ref: whatsnew/3 7 dis1137006
Ref: b4b1137006
Ref: dis<3>-Footnote-11137409
Node: distutils<4>1137474
Ref: whatsnew/3 7 distutils1137573
Ref: b4d1137573
Ref: distutils<4>-Footnote-11137821
Node: enum<5>1137886
Ref: whatsnew/3 7 enum1137991
Ref: b4e1137991
Ref: enum<5>-Footnote-11138665
Ref: enum<5>-Footnote-21138730
Node: functools<3>1138795
Ref: whatsnew/3 7 functools1138893
Ref: b501138893
Ref: functools<3>-Footnote-11139122
Node: gc<4>1139187
Ref: whatsnew/3 7 gc1139285
Ref: b511139285
Ref: gc<4>-Footnote-11139824
Node: hmac<2>1139889
Ref: whatsnew/3 7 hmac1139986
Ref: b551139986
Ref: hmac<2>-Footnote-11140249
Node: http client1140314
Ref: whatsnew/3 7 http-client1140417
Ref: b581140417
Ref: http client-Footnote-11140674
Node: http server1140739
Ref: whatsnew/3 7 http-server1140851
Ref: b5b1140851
Ref: http server-Footnote-11141734
Ref: http server-Footnote-21141799
Ref: http server-Footnote-31141864
Node: idlelib and IDLE1141929
Ref: whatsnew/3 7 idlelib-and-idle1142042
Ref: b5f1142042
Ref: idlelib and IDLE-Footnote-11145051
Ref: idlelib and IDLE-Footnote-21145116
Ref: idlelib and IDLE-Footnote-31145183
Ref: idlelib and IDLE-Footnote-41145248
Ref: idlelib and IDLE-Footnote-51145313
Ref: idlelib and IDLE-Footnote-61145378
Ref: idlelib and IDLE-Footnote-71145443
Ref: idlelib and IDLE-Footnote-81145508
Ref: idlelib and IDLE-Footnote-91145573
Ref: idlelib and IDLE-Footnote-101145638
Ref: idlelib and IDLE-Footnote-111145706
Ref: idlelib and IDLE-Footnote-121145771
Ref: idlelib and IDLE-Footnote-131145837
Node: importlib<4>1145903
Ref: whatsnew/3 7 importlib1146010
Ref: b601146010
Ref: importlib<4>-Footnote-11146903
Ref: importlib<4>-Footnote-21146968
Ref: importlib<4>-Footnote-31147033
Node: io<4>1147098
Ref: whatsnew/3 7 io1147201
Ref: b631147201
Ref: io<4>-Footnote-11147466
Ref: io<4>-Footnote-21147531
Node: ipaddress<3>1147596
Ref: whatsnew/3 7 ipaddress1147699
Ref: b651147699
Ref: ipaddress<3>-Footnote-11148019
Node: itertools<5>1148084
Ref: whatsnew/3 7 itertools1148191
Ref: b661148191
Ref: itertools<5>-Footnote-11148428
Node: locale<4>1148493
Ref: whatsnew/3 7 locale1148598
Ref: b681148598
Ref: locale<4>-Footnote-11149012
Node: logging<3>1149077
Ref: whatsnew/3 7 logging1149177
Ref: b691149177
Ref: logging<3>-Footnote-11149701
Ref: logging<3>-Footnote-21149766
Ref: logging<3>-Footnote-31149831
Node: math<6>1149896
Ref: whatsnew/3 7 math1149999
Ref: b6d1149999
Ref: math<6>-Footnote-11150212
Node: mimetypes<2>1150277
Ref: whatsnew/3 7 mimetypes1150376
Ref: b6f1150376
Ref: mimetypes<2>-Footnote-11150591
Node: msilib1150656
Ref: whatsnew/3 7 msilib1150766
Ref: b701150766
Ref: msilib-Footnote-11150961
Node: multiprocessing<4>1151026
Ref: whatsnew/3 7 multiprocessing1151129
Ref: b711151129
Ref: multiprocessing<4>-Footnote-11151782
Ref: multiprocessing<4>-Footnote-21151847
Ref: multiprocessing<4>-Footnote-31151912
Node: os<7>1151977
Ref: whatsnew/3 7 os1152084
Ref: b761152084
Ref: os<7>-Footnote-11153382
Ref: os<7>-Footnote-21153447
Ref: os<7>-Footnote-31153512
Ref: os<7>-Footnote-41153577
Ref: os<7>-Footnote-51153642
Ref: os<7>-Footnote-61153707
Ref: os<7>-Footnote-71153772
Node: pathlib<8>1153837
Ref: whatsnew/3 7 pathlib1153932
Ref: b811153932
Ref: pathlib<8>-Footnote-11154192
Node: pdb<4>1154257
Ref: whatsnew/3 7 pdb1154360
Ref: b821154360
Ref: pdb<4>-Footnote-11154770
Ref: pdb<4>-Footnote-21154835
Node: py_compile<3>1154900
Ref: whatsnew/3 7 py-compile1155001
Ref: b831155001
Ref: py_compile<3>-Footnote-11155455
Ref: py_compile<3>-Footnote-21155496
Node: pydoc<2>1155561
Ref: whatsnew/3 7 pydoc1155664
Ref: b841155664
Ref: pydoc<2>-Footnote-11155888
Node: queue<2>1155953
Ref: whatsnew/3 7 queue1156048
Ref: b851156048
Ref: queue<2>-Footnote-11156231
Node: re<4>1156296
Ref: whatsnew/3 7 re1156392
Ref: b871156392
Ref: re<4>-Footnote-11157474
Ref: re<4>-Footnote-21157539
Ref: re<4>-Footnote-31157604
Ref: re<4>-Footnote-41157669
Ref: re<4>-Footnote-51157734
Node: signal<2>1157799
Ref: whatsnew/3 7 signal1157896
Ref: b8b1157896
Ref: signal<2>-Footnote-11158215
Node: socket<5>1158280
Ref: whatsnew/3 7 socket1158384
Ref: b8d1158384
Ref: socket<5>-Footnote-11159490
Ref: socket<5>-Footnote-21159555
Ref: socket<5>-Footnote-31159620
Ref: socket<5>-Footnote-41159685
Ref: socket<5>-Footnote-51159750
Ref: socket<5>-Footnote-61159815
Node: socketserver1159880
Ref: whatsnew/3 7 socketserver1159985
Ref: b931159985
Node: sqlite3<6>1160469
Ref: whatsnew/3 7 sqlite31160571
Ref: b971160571
Ref: sqlite3<6>-Footnote-11161013
Ref: sqlite3<6>-Footnote-21161078
Node: ssl<5>1161143
Ref: whatsnew/3 7 ssl1161242
Ref: b991161242
Ref: ssl<5>-Footnote-11164508
Ref: ssl<5>-Footnote-21164573
Ref: ssl<5>-Footnote-31164638
Ref: ssl<5>-Footnote-41164703
Ref: ssl<5>-Footnote-51164768
Ref: ssl<5>-Footnote-61164833
Ref: ssl<5>-Footnote-71164898
Ref: ssl<5>-Footnote-81164963
Ref: ssl<5>-Footnote-91165028
Ref: ssl<5>-Footnote-101165093
Ref: ssl<5>-Footnote-111165159
Ref: ssl<5>-Footnote-121165225
Ref: ssl<5>-Footnote-131165291
Ref: ssl<5>-Footnote-141165357
Node: string<2>1165413
Ref: whatsnew/3 7 string1165515
Ref: ba21165515
Ref: string<2>-Footnote-11165792
Node: subprocess<2>1165859
Ref: whatsnew/3 7 subprocess1165961
Ref: ba31165961
Ref: subprocess<2>-Footnote-11167283
Ref: subprocess<2>-Footnote-21167348
Ref: subprocess<2>-Footnote-31167413
Ref: subprocess<2>-Footnote-41167478
Node: sys<8>1167543
Ref: whatsnew/3 7 sys1167643
Ref: ba71167643
Ref: sys<8>-Footnote-11168383
Ref: sys<8>-Footnote-21168448
Ref: sys<8>-Footnote-31168513
Node: time<5>1168578
Ref: whatsnew/3 7 time1168675
Ref: bab1168675
Ref: time<5>-Footnote-11169884
Ref: time<5>-Footnote-21169926
Node: tkinter<5>1169991
Ref: whatsnew/3 7 tkinter1170096
Ref: bb11170096
Ref: tkinter<5>-Footnote-11170277
Node: tracemalloc<2>1170342
Ref: whatsnew/3 7 tracemalloc1170448
Ref: bb31170448
Ref: tracemalloc<2>-Footnote-11170914
Node: types<4>1170979
Ref: whatsnew/3 7 types1171089
Ref: bb61171089
Ref: types<4>-Footnote-11171604
Ref: types<4>-Footnote-21171669
Ref: types<4>-Footnote-31171734
Ref: types<4>-Footnote-41171776
Node: unicodedata<6>1171841
Ref: whatsnew/3 7 unicodedata1171948
Ref: bbb1171948
Ref: unicodedata<6>-Footnote-11172151
Node: unittest<7>1172207
Ref: whatsnew/3 7 unittest1172319
Ref: bbc1172319
Ref: unittest<7>-Footnote-11172724
Node: unittest mock1172789
Ref: whatsnew/3 7 unittest-mock1172902
Ref: bbd1172902
Ref: unittest mock-Footnote-11173420
Ref: unittest mock-Footnote-21173485
Node: urllib parse<5>1173550
Ref: whatsnew/3 7 urllib-parse1173654
Ref: bc01173654
Ref: urllib parse<5>-Footnote-11173967
Ref: urllib parse<5>-Footnote-21174026
Ref: urllib parse<5>-Footnote-31174085
Node: uu1174150
Ref: whatsnew/3 7 uu1174248
Ref: bc21174248
Ref: uu-Footnote-11174514
Node: uuid<2>1174579
Ref: whatsnew/3 7 uuid1174673
Ref: bc31174673
Ref: uuid<2>-Footnote-11175313
Ref: uuid<2>-Footnote-21175378
Node: warnings<3>1175443
Ref: whatsnew/3 7 warnings1175541
Ref: bc71175541
Ref: warnings<3>-Footnote-11176966
Ref: warnings<3>-Footnote-21177031
Ref: warnings<3>-Footnote-31177096
Ref: warnings<3>-Footnote-41177161
Node: xml<5>1177226
Ref: whatsnew/3 7 xml1177326
Ref: bc91177326
Ref: xml<5>-Footnote-11177610
Node: xml etree1177665
Ref: whatsnew/3 7 xml-etree1177767
Ref: bca1177767
Ref: xml etree-Footnote-11178108
Node: xmlrpc server1178173
Ref: whatsnew/3 7 xmlrpc-server1178275
Ref: bcc1178275
Ref: xmlrpc server-Footnote-11178486
Node: zipapp1178550
Ref: whatsnew/3 7 zipapp1178653
Ref: bcd1178653
Ref: zipapp-Footnote-11179177
Ref: zipapp-Footnote-21179242
Node: zipfile<2>1179307
Ref: whatsnew/3 7 zipfile1179388
Ref: bcf1179388
Ref: zipfile<2>-Footnote-11179753
Ref: zipfile<2>-Footnote-21179818
Node: C API Changes<6>1179883
Ref: whatsnew/3 7 c-api-changes1180015
Ref: bd01180015
Ref: C API Changes<6>-Footnote-11184515
Ref: C API Changes<6>-Footnote-21184580
Ref: C API Changes<6>-Footnote-31184645
Ref: C API Changes<6>-Footnote-41184710
Ref: C API Changes<6>-Footnote-51184775
Ref: C API Changes<6>-Footnote-61184840
Ref: C API Changes<6>-Footnote-71184905
Ref: C API Changes<6>-Footnote-81184970
Ref: C API Changes<6>-Footnote-91185035
Ref: C API Changes<6>-Footnote-101185100
Ref: C API Changes<6>-Footnote-111185166
Ref: C API Changes<6>-Footnote-121185232
Ref: C API Changes<6>-Footnote-131185298
Ref: C API Changes<6>-Footnote-141185364
Ref: C API Changes<6>-Footnote-151185430
Ref: C API Changes<6>-Footnote-161185495
Ref: C API Changes<6>-Footnote-171185561
Ref: C API Changes<6>-Footnote-181185627
Ref: C API Changes<6>-Footnote-191185693
Ref: C API Changes<6>-Footnote-201185759
Node: Build Changes<6>1185825
Ref: whatsnew/3 7 build-changes1185954
Ref: bea1185954
Ref: Build Changes<6>-Footnote-11187087
Ref: Build Changes<6>-Footnote-21187152
Ref: Build Changes<6>-Footnote-31187217
Node: Optimizations<7>1187282
Ref: whatsnew/3 7 optimizations1187434
Ref: beb1187434
Ref: whatsnew/3 7 whatsnew37-perf1187434
Ref: ae61187434
Ref: whatsnew/3 7 whatsnew37-asyncio-perf1188128
Ref: b1b1188128
Ref: Optimizations<7>-Footnote-11192712
Ref: Optimizations<7>-Footnote-21192777
Ref: Optimizations<7>-Footnote-31192842
Ref: Optimizations<7>-Footnote-41192907
Ref: Optimizations<7>-Footnote-51192972
Ref: Optimizations<7>-Footnote-61193037
Ref: Optimizations<7>-Footnote-71193102
Ref: Optimizations<7>-Footnote-81193167
Ref: Optimizations<7>-Footnote-91193232
Ref: Optimizations<7>-Footnote-101193297
Ref: Optimizations<7>-Footnote-111193363
Ref: Optimizations<7>-Footnote-121193429
Ref: Optimizations<7>-Footnote-131193495
Ref: Optimizations<7>-Footnote-141193561
Ref: Optimizations<7>-Footnote-151193627
Ref: Optimizations<7>-Footnote-161193693
Ref: Optimizations<7>-Footnote-171193759
Ref: Optimizations<7>-Footnote-181193825
Ref: Optimizations<7>-Footnote-191193891
Ref: Optimizations<7>-Footnote-201193957
Ref: Optimizations<7>-Footnote-211194023
Ref: Optimizations<7>-Footnote-221194089
Ref: Optimizations<7>-Footnote-231194155
Ref: Optimizations<7>-Footnote-241194221
Ref: Optimizations<7>-Footnote-251194287
Ref: Optimizations<7>-Footnote-261194353
Ref: Optimizations<7>-Footnote-271194419
Ref: Optimizations<7>-Footnote-281194485
Ref: Optimizations<7>-Footnote-291194551
Ref: Optimizations<7>-Footnote-301194617
Node: Other CPython Implementation Changes<2>1194683
Ref: whatsnew/3 7 other-cpython-implementation-changes1194845
Ref: bfb1194845
Ref: Other CPython Implementation Changes<2>-Footnote-11196252
Ref: Other CPython Implementation Changes<2>-Footnote-21196317
Ref: Other CPython Implementation Changes<2>-Footnote-31196382
Ref: Other CPython Implementation Changes<2>-Footnote-41196447
Ref: Other CPython Implementation Changes<2>-Footnote-51196512
Node: Deprecated Python Behavior1196577
Ref: whatsnew/3 7 deprecated-python-behavior1196770
Ref: bfe1196770
Ref: Deprecated Python Behavior-Footnote-11197879
Ref: Deprecated Python Behavior-Footnote-21197944
Node: Deprecated Python modules functions and methods1198009
Ref: whatsnew/3 7 deprecated-python-modules-functions-and-methods1198206
Ref: c001198206
Node: aifc1198604
Ref: whatsnew/3 7 aifc1198711
Ref: c011198711
Ref: aifc-Footnote-11198931
Node: asyncio<8>1198996
Ref: whatsnew/3 7 id21199126
Ref: c021199126
Ref: whatsnew/3 7 whatsnew37-asyncio-deprecated1199126
Ref: b371199126
Ref: asyncio<8>-Footnote-11199651
Ref: asyncio<8>-Footnote-21199716
Node: collections<3>1199781
Ref: whatsnew/3 7 id31199913
Ref: c031199913
Ref: collections<3>-Footnote-11200292
Node: dbm<3>1200357
Ref: whatsnew/3 7 id41200486
Ref: c041200486
Ref: dbm<3>-Footnote-11200887
Node: enum<6>1200952
Ref: whatsnew/3 7 id51201077
Ref: c051201077
Ref: enum<6>-Footnote-11201533
Node: gettext<2>1201598
Ref: whatsnew/3 7 gettext1201729
Ref: c061201729
Ref: gettext<2>-Footnote-11201974
Node: importlib<5>1202039
Ref: whatsnew/3 7 id61202172
Ref: c071202172
Ref: importlib<5>-Footnote-11202687
Node: locale<5>1202752
Ref: whatsnew/3 7 id71202882
Ref: c091202882
Ref: locale<5>-Footnote-11203085
Node: macpath1203150
Ref: whatsnew/3 7 macpath1203280
Ref: c0a1203280
Ref: macpath-Footnote-11203470
Node: threading<5>1203534
Ref: whatsnew/3 7 threading1203664
Ref: c0b1203664
Ref: threading<5>-Footnote-11203962
Node: socket<6>1204027
Ref: whatsnew/3 7 id81204156
Ref: c0c1204156
Ref: socket<6>-Footnote-11204501
Node: ssl<6>1204566
Ref: whatsnew/3 7 id91204688
Ref: c0d1204688
Ref: ssl<6>-Footnote-11204900
Node: sunau1204965
Ref: whatsnew/3 7 sunau1205084
Ref: c0e1205084
Ref: sunau-Footnote-11205310
Node: sys<9>1205375
Ref: whatsnew/3 7 id101205492
Ref: c0f1205492
Ref: sys<9>-Footnote-11205809
Node: wave1205874
Ref: whatsnew/3 7 wave1205977
Ref: c101205977
Ref: wave-Footnote-11206205
Node: Deprecated functions and types of the C API1206270
Ref: whatsnew/3 7 deprecated-functions-and-types-of-the-c-api1206466
Ref: c111206466
Ref: Deprecated functions and types of the C API-Footnote-11207124
Ref: Deprecated functions and types of the C API-Footnote-21207189
Node: Platform Support Removals1207254
Ref: whatsnew/3 7 id111207430
Ref: c121207430
Ref: whatsnew/3 7 platform-support-removals1207430
Ref: b9c1207430
Ref: Platform Support Removals-Footnote-11208842
Ref: Platform Support Removals-Footnote-21208909
Node: API and Feature Removals<2>1208989
Ref: whatsnew/3 7 api-and-feature-removals1209137
Ref: c131209137
Ref: API and Feature Removals<2>-Footnote-11212044
Ref: API and Feature Removals<2>-Footnote-21212109
Ref: API and Feature Removals<2>-Footnote-31212174
Node: Module Removals1212239
Ref: whatsnew/3 7 module-removals1212382
Ref: c171212382
Ref: Module Removals-Footnote-11212717
Node: Windows-only Changes1212782
Ref: whatsnew/3 7 windows-only-changes1212919
Ref: c181212919
Ref: Windows-only Changes-Footnote-11213796
Ref: Windows-only Changes-Footnote-21213861
Node: Porting to Python 3 71213926
Ref: whatsnew/3 7 porting-to-python-3-71214079
Ref: c191214079
Ref: whatsnew/3 7 porting-to-python-371214079
Ref: ae71214079
Node: Changes in Python Behavior1214541
Ref: whatsnew/3 7 changes-in-python-behavior1214662
Ref: c1a1214662
Ref: Changes in Python Behavior-Footnote-11216528
Ref: Changes in Python Behavior-Footnote-21216593
Ref: Changes in Python Behavior-Footnote-31216635
Ref: Changes in Python Behavior-Footnote-41216700
Ref: Changes in Python Behavior-Footnote-51216765
Ref: Changes in Python Behavior-Footnote-61216830
Node: Changes in the Python API<7>1216895
Ref: whatsnew/3 7 changes-in-the-python-api1217048
Ref: c1d1217048
Ref: Changes in the Python API<7>-Footnote-11226610
Ref: Changes in the Python API<7>-Footnote-21226675
Ref: Changes in the Python API<7>-Footnote-31226740
Ref: Changes in the Python API<7>-Footnote-41226805
Ref: Changes in the Python API<7>-Footnote-51226870
Ref: Changes in the Python API<7>-Footnote-61226935
Ref: Changes in the Python API<7>-Footnote-71227000
Ref: Changes in the Python API<7>-Footnote-81227065
Ref: Changes in the Python API<7>-Footnote-91227130
Ref: Changes in the Python API<7>-Footnote-101227195
Ref: Changes in the Python API<7>-Footnote-111227261
Ref: Changes in the Python API<7>-Footnote-121227327
Ref: Changes in the Python API<7>-Footnote-131227393
Ref: Changes in the Python API<7>-Footnote-141227459
Ref: Changes in the Python API<7>-Footnote-151227502
Ref: Changes in the Python API<7>-Footnote-161227568
Ref: Changes in the Python API<7>-Footnote-171227634
Ref: Changes in the Python API<7>-Footnote-181227700
Ref: Changes in the Python API<7>-Footnote-191227766
Ref: Changes in the Python API<7>-Footnote-201227832
Ref: Changes in the Python API<7>-Footnote-211227898
Ref: Changes in the Python API<7>-Footnote-221227964
Ref: Changes in the Python API<7>-Footnote-231228030
Ref: Changes in the Python API<7>-Footnote-241228096
Ref: Changes in the Python API<7>-Footnote-251228162
Ref: Changes in the Python API<7>-Footnote-261228228
Ref: Changes in the Python API<7>-Footnote-271228294
Ref: Changes in the Python API<7>-Footnote-281228360
Ref: Changes in the Python API<7>-Footnote-291228426
Ref: Changes in the Python API<7>-Footnote-301228492
Node: Changes in the C API<5>1228558
Ref: whatsnew/3 7 changes-in-the-c-api1228712
Ref: c3d1228712
Ref: Changes in the C API<5>-Footnote-11229348
Node: CPython bytecode changes<6>1229413
Ref: whatsnew/3 7 cpython-bytecode-changes1229562
Ref: c3e1229562
Ref: CPython bytecode changes<6>-Footnote-11229908
Ref: CPython bytecode changes<6>-Footnote-21229973
Node: Windows-only Changes<2>1230038
Ref: whatsnew/3 7 id121230200
Ref: c401230200
Ref: Windows-only Changes<2>-Footnote-11230521
Node: Other CPython implementation changes1230586
Ref: whatsnew/3 7 id131230712
Ref: c421230712
Ref: Other CPython implementation changes-Footnote-11233042
Ref: Other CPython implementation changes-Footnote-21233084
Ref: Other CPython implementation changes-Footnote-31233149
Node: Notable changes in Python 3 7 11233214
Ref: whatsnew/3 7 notable-changes-in-python-3-7-11233378
Ref: c441233378
Ref: Notable changes in Python 3 7 1-Footnote-11234310
Ref: Notable changes in Python 3 7 1-Footnote-21234375
Ref: Notable changes in Python 3 7 1-Footnote-31234440
Node: Notable changes in Python 3 7 21234505
Ref: whatsnew/3 7 notable-changes-in-python-3-7-21234679
Ref: c471234679
Node: Notable changes in Python 3 7 61235174
Ref: whatsnew/3 7 notable-changes-in-python-3-7-61235349
Ref: c481235349
Ref: Notable changes in Python 3 7 6-Footnote-11235860
Node: Notable changes in Python 3 7 101235925
Ref: whatsnew/3 7 notable-changes-in-python-3-7-101236101
Ref: c491236101
Ref: Notable changes in Python 3 7 10-Footnote-11236821
Node: Notable changes in Python 3 7 111236886
Ref: whatsnew/3 7 notable-changes-in-python-3-7-111237065
Ref: c4a1237065
Ref: Notable changes in Python 3 7 11-Footnote-11237982
Ref: Notable changes in Python 3 7 11-Footnote-21238037
Node: Notable security feature in 3 7 141238092
Ref: whatsnew/3 7 notable-security-feature-in-3-7-141238230
Ref: c4b1238230
Ref: Notable security feature in 3 7 14-Footnote-11238960
Node: What’s New In Python 3 61239016
Ref: whatsnew/3 6 doc1239171
Ref: c4c1239171
Ref: whatsnew/3 6 translation-repo1239171
Ref: c4d1239171
Ref: whatsnew/3 6 what-s-new-in-python-3-61239171
Ref: c4e1239171
Ref: What’s New In Python 3 6-Footnote-11240516
Ref: What’s New In Python 3 6-Footnote-21240576
Node: Summary – Release highlights<6>1240618
Ref: whatsnew/3 6 summary-release-highlights1240739
Ref: c4f1240739
Ref: Summary – Release highlights<6>-Footnote-11244979
Ref: Summary – Release highlights<6>-Footnote-21245059
Ref: Summary – Release highlights<6>-Footnote-31245149
Node: New Features<13>1245191
Ref: whatsnew/3 6 new-features1245346
Ref: c631245346
Ref: whatsnew/3 6 pypy-dict-implementation1245346
Ref: c641245346
Node: PEP 498 Formatted string literals1246756
Ref: whatsnew/3 6 pep-498-formatted-string-literals1246890
Ref: c651246890
Ref: whatsnew/3 6 whatsnew36-pep4981246890
Ref: c501246890
Ref: PEP 498 Formatted string literals-Footnote-11247874
Ref: PEP 498 Formatted string literals-Footnote-21247916
Node: PEP 526 Syntax for variable annotations1247958
Ref: whatsnew/3 6 pep-526-syntax-for-variable-annotations1248140
Ref: c661248140
Ref: whatsnew/3 6 whatsnew36-pep5261248140
Ref: c521248140
Ref: PEP 526 Syntax for variable annotations-Footnote-11249384
Ref: PEP 526 Syntax for variable annotations-Footnote-21249426
Ref: PEP 526 Syntax for variable annotations-Footnote-31249468
Ref: PEP 526 Syntax for variable annotations-Footnote-41249503
Node: PEP 515 Underscores in Numeric Literals1249544
Ref: whatsnew/3 6 pep-515-underscores-in-numeric-literals1249724
Ref: c671249724
Ref: whatsnew/3 6 whatsnew36-pep5151249724
Ref: c511249724
Ref: PEP 515 Underscores in Numeric Literals-Footnote-11250793
Ref: PEP 515 Underscores in Numeric Literals-Footnote-21250835
Node: PEP 525 Asynchronous Generators1250877
Ref: whatsnew/3 6 pep-525-asynchronous-generators1251053
Ref: c681251053
Ref: whatsnew/3 6 whatsnew36-pep5251251053
Ref: c531251053
Ref: PEP 525 Asynchronous Generators-Footnote-11251888
Ref: PEP 525 Asynchronous Generators-Footnote-21251930
Node: PEP 530 Asynchronous Comprehensions1251972
Ref: whatsnew/3 6 pep-530-asynchronous-comprehensions1252156
Ref: c691252156
Ref: whatsnew/3 6 whatsnew36-pep5301252156
Ref: c541252156
Ref: PEP 530 Asynchronous Comprehensions-Footnote-11252714
Ref: PEP 530 Asynchronous Comprehensions-Footnote-21252756
Node: PEP 487 Simpler customization of class creation1252798
Ref: whatsnew/3 6 pep-487-simpler-customization-of-class-creation1252991
Ref: c6a1252991
Ref: whatsnew/3 6 whatsnew36-pep4871252991
Ref: c571252991
Ref: PEP 487 Simpler customization of class creation-Footnote-11254083
Node: PEP 487 Descriptor Protocol Enhancements1254125
Ref: whatsnew/3 6 pep-487-descriptor-protocol-enhancements1254325
Ref: c6d1254325
Ref: whatsnew/3 6 whatsnew36-pep487-descriptors1254325
Ref: c6e1254325
Ref: PEP 487 Descriptor Protocol Enhancements-Footnote-11255576
Ref: PEP 487 Descriptor Protocol Enhancements-Footnote-21255618
Node: PEP 519 Adding a file system path protocol1255660
Ref: whatsnew/3 6 pep-519-adding-a-file-system-path-protocol1255846
Ref: c711255846
Ref: whatsnew/3 6 whatsnew36-pep5191255846
Ref: c5c1255846
Ref: PEP 519 Adding a file system path protocol-Footnote-11258638
Node: PEP 495 Local Time Disambiguation1258680
Ref: whatsnew/3 6 pep-495-local-time-disambiguation1258877
Ref: c771258877
Ref: whatsnew/3 6 whatsnew36-pep4951258877
Ref: c5d1258877
Ref: PEP 495 Local Time Disambiguation-Footnote-11260290
Ref: PEP 495 Local Time Disambiguation-Footnote-21260332
Node: PEP 529 Change Windows filesystem encoding to UTF-81260374
Ref: whatsnew/3 6 pep-529-change-windows-filesystem-encoding-to-utf-81260577
Ref: c791260577
Ref: whatsnew/3 6 whatsnew36-pep5291260577
Ref: c611260577
Ref: PEP 529 Change Windows filesystem encoding to UTF-8-Footnote-11261607
Node: PEP 528 Change Windows console encoding to UTF-81261649
Ref: whatsnew/3 6 pep-528-change-windows-console-encoding-to-utf-81261870
Ref: c7b1261870
Ref: whatsnew/3 6 whatsnew36-pep5281261870
Ref: c601261870
Ref: PEP 528 Change Windows console encoding to UTF-8-Footnote-11262573
Node: PEP 520 Preserving Class Attribute Definition Order1262615
Ref: whatsnew/3 6 pep-520-preserving-class-attribute-definition-order1262826
Ref: c7d1262826
Ref: whatsnew/3 6 whatsnew36-pep5201262826
Ref: c581262826
Ref: PEP 520 Preserving Class Attribute Definition Order-Footnote-11263466
Node: PEP 468 Preserving Keyword Argument Order1263508
Ref: whatsnew/3 6 pep-468-preserving-keyword-argument-order1263694
Ref: c801263694
Ref: whatsnew/3 6 whatsnew36-pep4681263694
Ref: c591263694
Ref: PEP 468 Preserving Keyword Argument Order-Footnote-11264055
Node: New dict implementation1264097
Ref: whatsnew/3 6 new-dict-implementation1264280
Ref: c811264280
Ref: whatsnew/3 6 whatsnew36-compactdict1264280
Ref: c561264280
Ref: New dict implementation-Footnote-11265258
Ref: New dict implementation-Footnote-21265338
Ref: New dict implementation-Footnote-31265428
Ref: New dict implementation-Footnote-41265493
Node: PEP 523 Adding a frame evaluation API to CPython1265573
Ref: whatsnew/3 6 pep-523-adding-a-frame-evaluation-api-to-cpython1265748
Ref: c821265748
Ref: whatsnew/3 6 whatsnew36-pep5231265748
Ref: c831265748
Ref: PEP 523 Adding a frame evaluation API to CPython-Footnote-11266919
Ref: PEP 523 Adding a frame evaluation API to CPython-Footnote-21266961
Node: PYTHONMALLOC environment variable1267003
Ref: whatsnew/3 6 pythonmalloc-environment-variable1267191
Ref: c841267191
Ref: whatsnew/3 6 whatsnew36-pythonmalloc1267191
Ref: c5b1267191
Ref: PYTHONMALLOC environment variable-Footnote-11270373
Ref: PYTHONMALLOC environment variable-Footnote-21270438
Node: DTrace and SystemTap probing support1270503
Ref: whatsnew/3 6 dtrace-and-systemtap-probing-support1270634
Ref: c8c1270634
Ref: whatsnew/3 6 whatsnew36-tracing1270634
Ref: c5a1270634
Ref: DTrace and SystemTap probing support-Footnote-11271477
Node: Other Language Changes<8>1271542
Ref: whatsnew/3 6 other-language-changes1271678
Ref: c8e1271678
Ref: Other Language Changes<8>-Footnote-11273063
Ref: Other Language Changes<8>-Footnote-21273128
Ref: Other Language Changes<8>-Footnote-31273193
Ref: Other Language Changes<8>-Footnote-41273258
Node: New Modules<8>1273323
Ref: whatsnew/3 6 new-modules1273462
Ref: c921273462
Node: secrets1273521
Ref: whatsnew/3 6 secrets1273579
Ref: c931273579
Ref: whatsnew/3 6 whatsnew36-pep5061273579
Ref: c551273579
Ref: secrets-Footnote-11274262
Node: Improved Modules<8>1274304
Ref: whatsnew/3 6 improved-modules1274434
Ref: c941274434
Node: array<4>1275918
Ref: whatsnew/3 6 array1275997
Ref: c951275997
Ref: array<4>-Footnote-11276290
Node: ast<4>1276355
Ref: whatsnew/3 6 ast1276453
Ref: c961276453
Ref: ast<4>-Footnote-11276702
Node: asyncio<9>1276767
Ref: whatsnew/3 6 asyncio1276868
Ref: c971276868
Ref: asyncio<9>-Footnote-11280215
Ref: asyncio<9>-Footnote-21280280
Ref: asyncio<9>-Footnote-31280325
Ref: asyncio<9>-Footnote-41280390
Ref: asyncio<9>-Footnote-51280455
Ref: asyncio<9>-Footnote-61280520
Ref: asyncio<9>-Footnote-71280585
Ref: asyncio<9>-Footnote-81280650
Ref: asyncio<9>-Footnote-91280715
Ref: asyncio<9>-Footnote-101280780
Ref: asyncio<9>-Footnote-111280846
Ref: asyncio<9>-Footnote-121280912
Node: binascii<2>1280978
Ref: whatsnew/3 6 binascii1281078
Ref: ca11281078
Ref: binascii<2>-Footnote-11281363
Node: cmath1281428
Ref: whatsnew/3 6 cmath1281532
Ref: ca31281532
Ref: cmath-Footnote-11282003
Ref: cmath-Footnote-21282068
Ref: cmath-Footnote-31282110
Node: collections<4>1282175
Ref: whatsnew/3 6 collections1282289
Ref: caa1282289
Ref: collections<4>-Footnote-11283395
Ref: collections<4>-Footnote-21283460
Ref: collections<4>-Footnote-31283525
Ref: collections<4>-Footnote-41283590
Ref: collections<4>-Footnote-51283655
Ref: collections<4>-Footnote-61283720
Node: concurrent futures<4>1283785
Ref: whatsnew/3 6 concurrent-futures1283907
Ref: caf1283907
Ref: concurrent futures<4>-Footnote-11284238
Node: contextlib<4>1284303
Ref: whatsnew/3 6 contextlib1284422
Ref: cb01284422
Ref: contextlib<4>-Footnote-11284918
Node: datetime<5>1284983
Ref: whatsnew/3 6 datetime1285091
Ref: cb31285091
Ref: datetime<5>-Footnote-11286113
Ref: datetime<5>-Footnote-21286178
Ref: datetime<5>-Footnote-31286243
Ref: datetime<5>-Footnote-41286308
Node: decimal<2>1286373
Ref: whatsnew/3 6 decimal1286480
Ref: cb81286480
Ref: decimal<2>-Footnote-11286893
Node: distutils<5>1286958
Ref: whatsnew/3 6 distutils1287062
Ref: cba1287062
Ref: distutils<5>-Footnote-11287436
Node: email<2>1287501
Ref: whatsnew/3 6 email1287607
Ref: cbb1287607
Ref: email<2>-Footnote-11288523
Ref: email<2>-Footnote-21288588
Ref: email<2>-Footnote-31288653
Node: encodings<2>1288718
Ref: whatsnew/3 6 encodings1288819
Ref: cbf1288819
Ref: encodings<2>-Footnote-11289114
Node: enum<7>1289179
Ref: whatsnew/3 6 enum1289287
Ref: cc01289287
Ref: enum<7>-Footnote-11290044
Node: faulthandler<2>1290109
Ref: whatsnew/3 6 faulthandler1290217
Ref: cc31290217
Ref: faulthandler<2>-Footnote-11290480
Node: fileinput<2>1290545
Ref: whatsnew/3 6 fileinput1290656
Ref: cc51290656
Ref: fileinput<2>-Footnote-11290844
Node: hashlib<5>1290909
Ref: whatsnew/3 6 hashlib1291019
Ref: cc71291019
Ref: hashlib<5>-Footnote-11292068
Ref: hashlib<5>-Footnote-21292133
Ref: hashlib<5>-Footnote-31292198
Ref: hashlib<5>-Footnote-41292263
Node: http client<2>1292328
Ref: whatsnew/3 6 http-client1292445
Ref: cce1292445
Ref: http client<2>-Footnote-11292705
Node: idlelib and IDLE<2>1292770
Ref: whatsnew/3 6 idlelib-and-idle1292889
Ref: cd11292889
Ref: idlelib and IDLE<2>-Footnote-11296363
Ref: idlelib and IDLE<2>-Footnote-21296428
Ref: idlelib and IDLE<2>-Footnote-31296493
Ref: idlelib and IDLE<2>-Footnote-41296560
Ref: idlelib and IDLE<2>-Footnote-51296625
Ref: idlelib and IDLE<2>-Footnote-61296690
Ref: idlelib and IDLE<2>-Footnote-71296755
Ref: idlelib and IDLE<2>-Footnote-81296820
Ref: idlelib and IDLE<2>-Footnote-91296885
Ref: idlelib and IDLE<2>-Footnote-101296950
Ref: idlelib and IDLE<2>-Footnote-111297016
Node: importlib<6>1297084
Ref: whatsnew/3 6 importlib1297199
Ref: cd21297199
Ref: importlib<6>-Footnote-11298021
Node: inspect<6>1298086
Ref: whatsnew/3 6 inspect1298186
Ref: cd81298186
Ref: inspect<6>-Footnote-11298961
Ref: inspect<6>-Footnote-21299026
Node: json1299091
Ref: whatsnew/3 6 json1299189
Ref: cd91299189
Ref: json-Footnote-11299461
Node: logging<4>1299526
Ref: whatsnew/3 6 logging1299621
Ref: cdb1299621
Ref: logging<4>-Footnote-11299885
Node: math<7>1299950
Ref: whatsnew/3 6 math1300059
Ref: cdd1300059
Ref: math<7>-Footnote-11300291
Ref: math<7>-Footnote-21300356
Node: multiprocessing<5>1300398
Ref: whatsnew/3 6 multiprocessing1300502
Ref: cde1300502
Ref: multiprocessing<5>-Footnote-11300731
Node: os<8>1300795
Ref: whatsnew/3 6 os1300902
Ref: ce11300902
Ref: os<8>-Footnote-11301896
Ref: os<8>-Footnote-21301961
Ref: os<8>-Footnote-31302003
Node: pathlib<9>1302045
Ref: whatsnew/3 6 pathlib1302140
Ref: ce41302140
Ref: pathlib<9>-Footnote-11302374
Node: pdb<5>1302439
Ref: whatsnew/3 6 pdb1302538
Ref: ce51302538
Node: pickle<2>1302695
Ref: whatsnew/3 6 pickle1302795
Ref: ce61302795
Ref: pickle<2>-Footnote-11303112
Node: pickletools1303177
Ref: whatsnew/3 6 pickletools1303279
Ref: ce81303279
Ref: pickletools-Footnote-11303507
Node: pydoc<3>1303572
Ref: whatsnew/3 6 pydoc1303674
Ref: cea1303674
Ref: pydoc<3>-Footnote-11304068
Ref: pydoc<3>-Footnote-21304132
Node: random<4>1304197
Ref: whatsnew/3 6 random1304293
Ref: ceb1304293
Ref: random<4>-Footnote-11304548
Node: re<5>1304613
Ref: whatsnew/3 6 re1304709
Ref: ced1304709
Ref: re<5>-Footnote-11305420
Ref: re<5>-Footnote-21305486
Ref: re<5>-Footnote-31305551
Node: readline1305616
Ref: whatsnew/3 6 readline1305714
Ref: cef1305714
Ref: readline-Footnote-11305945
Node: rlcompleter1306010
Ref: whatsnew/3 6 rlcompleter1306111
Ref: cf11306111
Ref: rlcompleter-Footnote-11306415
Ref: rlcompleter-Footnote-21306480
Node: shlex<2>1306545
Ref: whatsnew/3 6 shlex1306645
Ref: cf21306645
Ref: shlex<2>-Footnote-11306935
Node: site<3>1307002
Ref: whatsnew/3 6 site1307101
Ref: cf51307101
Ref: site<3>-Footnote-11307365
Node: sqlite3<7>1307430
Ref: whatsnew/3 6 sqlite31307530
Ref: cf61307530
Ref: sqlite3<7>-Footnote-11307733
Node: socket<7>1307798
Ref: whatsnew/3 6 socket1307906
Ref: cf81307906
Ref: socket<7>-Footnote-11308863
Ref: socket<7>-Footnote-21308928
Ref: socket<7>-Footnote-31308993
Ref: socket<7>-Footnote-41309058
Ref: socket<7>-Footnote-51309123
Node: socketserver<2>1309188
Ref: whatsnew/3 6 socketserver1309292
Ref: cff1309292
Ref: socketserver<2>-Footnote-11309927
Ref: socketserver<2>-Footnote-21309992
Node: ssl<7>1310057
Ref: whatsnew/3 6 ssl1310165
Ref: d031310165
Ref: ssl<7>-Footnote-11311592
Ref: ssl<7>-Footnote-21311657
Ref: ssl<7>-Footnote-31311722
Ref: ssl<7>-Footnote-41311787
Ref: ssl<7>-Footnote-51311852
Ref: ssl<7>-Footnote-61311917
Ref: ssl<7>-Footnote-71311982
Ref: ssl<7>-Footnote-81312047
Node: statistics<5>1312102
Ref: whatsnew/3 6 statistics1312201
Ref: d071312201
Ref: statistics<5>-Footnote-11312391
Node: struct1312456
Ref: whatsnew/3 6 struct1312562
Ref: d091312562
Ref: struct-Footnote-11312793
Node: subprocess<3>1312858
Ref: whatsnew/3 6 subprocess1312958
Ref: d0a1312958
Ref: subprocess<3>-Footnote-11313651
Ref: subprocess<3>-Footnote-21313716
Node: sys<10>1313780
Ref: whatsnew/3 6 sys1313883
Ref: d0c1313883
Ref: sys<10>-Footnote-11314484
Ref: sys<10>-Footnote-21314549
Node: telnetlib1314614
Ref: whatsnew/3 6 telnetlib1314711
Ref: d0f1314711
Ref: telnetlib-Footnote-11314886
Node: time<6>1314951
Ref: whatsnew/3 6 time1315047
Ref: d101315047
Node: timeit1315186
Ref: whatsnew/3 6 timeit1315283
Ref: d121315283
Ref: timeit-Footnote-11315742
Ref: timeit-Footnote-21315806
Node: tkinter<6>1315871
Ref: whatsnew/3 6 tkinter1315973
Ref: d151315973
Ref: tkinter<6>-Footnote-11316417
Node: traceback<4>1316482
Ref: whatsnew/3 6 traceback1316592
Ref: d161316592
Ref: whatsnew/3 6 whatsnew36-traceback1316592
Ref: c911316592
Ref: traceback<4>-Footnote-11317227
Node: tracemalloc<3>1317292
Ref: whatsnew/3 6 tracemalloc1317401
Ref: d171317401
Ref: tracemalloc<3>-Footnote-11317761
Node: typing<9>1317826
Ref: whatsnew/3 6 typing1317937
Ref: d191317937
Ref: whatsnew/3 6 whatsnew36-typing1317937
Ref: c5e1317937
Ref: typing<9>-Footnote-11319589
Ref: typing<9>-Footnote-21319639
Ref: typing<9>-Footnote-31319704
Ref: typing<9>-Footnote-41319769
Ref: typing<9>-Footnote-51319811
Ref: typing<9>-Footnote-61319861
Ref: typing<9>-Footnote-71319913
Node: unicodedata<7>1319965
Ref: whatsnew/3 6 unicodedata1320078
Ref: d1d1320078
Ref: unicodedata<7>-Footnote-11320266
Node: unittest mock<2>1320317
Ref: whatsnew/3 6 unittest-mock1320435
Ref: d1e1320435
Ref: unittest mock<2>-Footnote-11320952
Ref: unittest mock<2>-Footnote-21321017
Node: urllib request1321082
Ref: whatsnew/3 6 urllib-request1321204
Ref: d221321204
Ref: urllib request-Footnote-11321576
Node: urllib robotparser1321641
Ref: whatsnew/3 6 urllib-robotparser1321754
Ref: d241321754
Ref: urllib robotparser-Footnote-11321999
Node: venv<5>1322064
Ref: whatsnew/3 6 venv1322174
Ref: d261322174
Ref: venv<5>-Footnote-11322461
Node: warnings<4>1322526
Ref: whatsnew/3 6 warnings1322624
Ref: d271322624
Ref: warnings<4>-Footnote-11323897
Ref: warnings<4>-Footnote-21323962
Node: winreg1324027
Ref: whatsnew/3 6 winreg1324126
Ref: d291324126
Ref: winreg-Footnote-11324299
Node: winsound1324364
Ref: whatsnew/3 6 winsound1324465
Ref: d2b1324465
Ref: winsound-Footnote-11324664
Node: xmlrpc client1324729
Ref: whatsnew/3 6 xmlrpc-client1324834
Ref: d2f1324834
Ref: xmlrpc client-Footnote-11325127
Node: zipfile<3>1325192
Ref: whatsnew/3 6 zipfile1325293
Ref: d301325293
Ref: zipfile<3>-Footnote-11325821
Ref: zipfile<3>-Footnote-21325886
Node: zlib1325951
Ref: whatsnew/3 6 zlib1326030
Ref: d341326030
Ref: zlib-Footnote-11326286
Ref: zlib-Footnote-21326351
Node: Optimizations<8>1326416
Ref: whatsnew/3 6 optimizations1326558
Ref: d361326558
Ref: Optimizations<8>-Footnote-11330427
Ref: Optimizations<8>-Footnote-21330492
Ref: Optimizations<8>-Footnote-31330557
Ref: Optimizations<8>-Footnote-41330622
Ref: Optimizations<8>-Footnote-51330687
Ref: Optimizations<8>-Footnote-61330752
Ref: Optimizations<8>-Footnote-71330817
Ref: Optimizations<8>-Footnote-81330882
Ref: Optimizations<8>-Footnote-91330947
Ref: Optimizations<8>-Footnote-101331012
Ref: Optimizations<8>-Footnote-111331078
Ref: Optimizations<8>-Footnote-121331144
Ref: Optimizations<8>-Footnote-131331210
Ref: Optimizations<8>-Footnote-141331276
Ref: Optimizations<8>-Footnote-151331342
Ref: Optimizations<8>-Footnote-161331408
Ref: Optimizations<8>-Footnote-171331474
Ref: Optimizations<8>-Footnote-181331540
Ref: Optimizations<8>-Footnote-191331606
Ref: Optimizations<8>-Footnote-201331672
Ref: Optimizations<8>-Footnote-211331738
Node: Build and C API Changes<2>1331804
Ref: whatsnew/3 6 build-and-c-api-changes1331945
Ref: d3c1331945
Ref: Build and C API Changes<2>-Footnote-11334398
Ref: Build and C API Changes<2>-Footnote-21334440
Ref: Build and C API Changes<2>-Footnote-31334505
Ref: Build and C API Changes<2>-Footnote-41334570
Ref: Build and C API Changes<2>-Footnote-51334635
Ref: Build and C API Changes<2>-Footnote-61334699
Ref: Build and C API Changes<2>-Footnote-71334764
Ref: Build and C API Changes<2>-Footnote-81334829
Ref: Build and C API Changes<2>-Footnote-91334894
Ref: Build and C API Changes<2>-Footnote-101334959
Node: Other Improvements1335025
Ref: whatsnew/3 6 other-improvements1335163
Ref: d421335163
Node: Deprecated<9>1335532
Ref: whatsnew/3 6 deprecated1335654
Ref: d441335654
Node: New Keywords1335990
Ref: whatsnew/3 6 new-keywords1336087
Ref: d451336087
Ref: New Keywords-Footnote-11336480
Node: Deprecated Python behavior1336522
Ref: whatsnew/3 6 deprecated-python-behavior1336678
Ref: d461336678
Ref: Deprecated Python behavior-Footnote-11337885
Ref: Deprecated Python behavior-Footnote-21337950
Ref: Deprecated Python behavior-Footnote-31338015
Node: Deprecated Python modules functions and methods<2>1338080
Ref: whatsnew/3 6 deprecated-python-modules-functions-and-methods1338230
Ref: d481338230
Node: asynchat1338539
Ref: whatsnew/3 6 asynchat1338651
Ref: d491338651
Ref: asynchat-Footnote-11338835
Node: asyncore1338900
Ref: whatsnew/3 6 asyncore1339027
Ref: d4a1339027
Ref: asyncore-Footnote-11339211
Node: dbm<4>1339276
Ref: whatsnew/3 6 dbm1339407
Ref: d4b1339407
Ref: dbm<4>-Footnote-11339767
Node: distutils<6>1339832
Ref: whatsnew/3 6 id21339958
Ref: d4c1339958
Ref: distutils<6>-Footnote-11340288
Node: grp1340353
Ref: whatsnew/3 6 grp1340485
Ref: d4d1340485
Ref: grp-Footnote-11340683
Node: importlib<7>1340748
Ref: whatsnew/3 6 id31340873
Ref: d4f1340873
Node: os<9>1341527
Ref: whatsnew/3 6 id41341654
Ref: d541341654
Ref: os<9>-Footnote-11341948
Ref: os<9>-Footnote-21342013
Node: re<6>1342078
Ref: whatsnew/3 6 id51342199
Ref: d561342199
Ref: re<6>-Footnote-11342525
Node: ssl<8>1342590
Ref: whatsnew/3 6 id61342716
Ref: d571342716
Ref: ssl<8>-Footnote-11343511
Ref: ssl<8>-Footnote-21343576
Ref: ssl<8>-Footnote-31343641
Node: tkinter<7>1343706
Ref: whatsnew/3 6 id71343834
Ref: d581343834
Node: venv<6>1343987
Ref: whatsnew/3 6 id81344100
Ref: d591344100
Ref: whatsnew/3 6 whatsnew36-venv1344100
Ref: d5a1344100
Ref: venv<6>-Footnote-11344451
Node: xml<6>1344516
Ref: whatsnew/3 6 xml1344686
Ref: d5b1344686
Ref: xml<6>-Footnote-11344990
Node: Deprecated functions and types of the C API<2>1345045
Ref: whatsnew/3 6 deprecated-functions-and-types-of-the-c-api1345189
Ref: d5c1345189
Node: Deprecated Build Options1345538
Ref: whatsnew/3 6 deprecated-build-options1345667
Ref: d5e1345667
Node: Removed<9>1346108
Ref: whatsnew/3 6 removed1346233
Ref: d5f1346233
Node: API and Feature Removals<3>1346331
Ref: whatsnew/3 6 api-and-feature-removals1346405
Ref: d601346405
Ref: API and Feature Removals<3>-Footnote-11348495
Ref: API and Feature Removals<3>-Footnote-21348560
Node: Porting to Python 3 61348638
Ref: whatsnew/3 6 porting-to-python-3-61348781
Ref: d631348781
Node: Changes in ‘python’ Command Behavior1349167
Ref: whatsnew/3 6 changes-in-python-command-behavior1349302
Ref: d641349302
Ref: Changes in ‘python’ Command Behavior-Footnote-11349782
Node: Changes in the Python API<8>1349847
Ref: whatsnew/3 6 changes-in-the-python-api1350014
Ref: d651350014
Ref: Changes in the Python API<8>-Footnote-11360095
Ref: Changes in the Python API<8>-Footnote-21360159
Ref: Changes in the Python API<8>-Footnote-31360201
Ref: Changes in the Python API<8>-Footnote-41360266
Ref: Changes in the Python API<8>-Footnote-51360331
Ref: Changes in the Python API<8>-Footnote-61360396
Ref: Changes in the Python API<8>-Footnote-71360461
Ref: Changes in the Python API<8>-Footnote-81360526
Ref: Changes in the Python API<8>-Footnote-91360591
Ref: Changes in the Python API<8>-Footnote-101360656
Ref: Changes in the Python API<8>-Footnote-111360722
Ref: Changes in the Python API<8>-Footnote-121360765
Ref: Changes in the Python API<8>-Footnote-131360831
Ref: Changes in the Python API<8>-Footnote-141360897
Ref: Changes in the Python API<8>-Footnote-151360963
Ref: Changes in the Python API<8>-Footnote-161361029
Ref: Changes in the Python API<8>-Footnote-171361094
Ref: Changes in the Python API<8>-Footnote-181361160
Ref: Changes in the Python API<8>-Footnote-191361226
Ref: Changes in the Python API<8>-Footnote-201361292
Node: Changes in the C API<6>1361358
Ref: whatsnew/3 6 changes-in-the-c-api1361512
Ref: d771361512
Ref: Changes in the C API<6>-Footnote-11362160
Ref: Changes in the C API<6>-Footnote-21362225
Node: CPython bytecode changes<7>1362289
Ref: whatsnew/3 6 cpython-bytecode-changes1362406
Ref: d791362406
Ref: CPython bytecode changes<7>-Footnote-11364032
Ref: CPython bytecode changes<7>-Footnote-21364097
Ref: CPython bytecode changes<7>-Footnote-31364162
Ref: CPython bytecode changes<7>-Footnote-41364227
Ref: CPython bytecode changes<7>-Footnote-51364292
Ref: CPython bytecode changes<7>-Footnote-61364357
Ref: CPython bytecode changes<7>-Footnote-71364422
Ref: CPython bytecode changes<7>-Footnote-81364487
Ref: CPython bytecode changes<7>-Footnote-91364552
Node: Notable changes in Python 3 6 21364617
Ref: whatsnew/3 6 notable-changes-in-python-3-6-21364781
Ref: d801364781
Node: New make regen-all build target1364945
Ref: whatsnew/3 6 new-make-regen-all-build-target1365087
Ref: d811365087
Ref: New make regen-all build target-Footnote-11365876
Ref: New make regen-all build target-Footnote-21365944
Node: Removal of make touch build target1366009
Ref: whatsnew/3 6 removal-of-make-touch-build-target1366151
Ref: d821366151
Ref: Removal of make touch build target-Footnote-11366581
Node: Notable changes in Python 3 6 41366646
Ref: whatsnew/3 6 notable-changes-in-python-3-6-41366820
Ref: d831366820
Ref: Notable changes in Python 3 6 4-Footnote-11367193
Ref: Notable changes in Python 3 6 4-Footnote-21367258
Node: Notable changes in Python 3 6 51367323
Ref: whatsnew/3 6 notable-changes-in-python-3-6-51367497
Ref: d841367497
Ref: Notable changes in Python 3 6 5-Footnote-11367800
Node: Notable changes in Python 3 6 71367865
Ref: whatsnew/3 6 notable-changes-in-python-3-6-71368040
Ref: d851368040
Ref: Notable changes in Python 3 6 7-Footnote-11368546
Ref: Notable changes in Python 3 6 7-Footnote-21368601
Node: Notable changes in Python 3 6 101368666
Ref: whatsnew/3 6 notable-changes-in-python-3-6-101368842
Ref: d861368842
Ref: Notable changes in Python 3 6 10-Footnote-11369355
Node: Notable changes in Python 3 6 131369420
Ref: whatsnew/3 6 notable-changes-in-python-3-6-131369597
Ref: d871369597
Ref: Notable changes in Python 3 6 13-Footnote-11370317
Node: Notable changes in Python 3 6 141370382
Ref: whatsnew/3 6 notable-changes-in-python-3-6-141370518
Ref: d881370518
Ref: Notable changes in Python 3 6 14-Footnote-11371435
Ref: Notable changes in Python 3 6 14-Footnote-21371490
Node: What’s New In Python 3 51371545
Ref: whatsnew/3 5 doc1371700
Ref: d891371700
Ref: whatsnew/3 5 translation-repo1371700
Ref: d8a1371700
Ref: whatsnew/3 5 what-s-new-in-python-3-51371700
Ref: d8b1371700
Ref: What’s New In Python 3 5-Footnote-11372642
Ref: What’s New In Python 3 5-Footnote-21372702
Node: Summary – Release highlights<7>1372744
Ref: whatsnew/3 5 summary-release-highlights1372865
Ref: d8c1372865
Ref: Summary – Release highlights<7>-Footnote-11376593
Ref: Summary – Release highlights<7>-Footnote-21376657
Ref: Summary – Release highlights<7>-Footnote-31376722
Ref: Summary – Release highlights<7>-Footnote-41376787
Ref: Summary – Release highlights<7>-Footnote-51376852
Ref: Summary – Release highlights<7>-Footnote-61376917
Ref: Summary – Release highlights<7>-Footnote-71376982
Node: New Features<14>1377047
Ref: whatsnew/3 5 new-features1377202
Ref: d9f1377202
Node: PEP 492 - Coroutines with async and await syntax1378298
Ref: whatsnew/3 5 pep-492-coroutines-with-async-and-await-syntax1378470
Ref: da01378470
Ref: whatsnew/3 5 whatsnew-pep-4921378470
Ref: d8d1378470
Ref: PEP 492 - Coroutines with async and await syntax-Footnote-11381549
Ref: PEP 492 - Coroutines with async and await syntax-Footnote-21381591
Node: PEP 465 - A dedicated infix operator for matrix multiplication1381633
Ref: whatsnew/3 5 pep-465-a-dedicated-infix-operator-for-matrix-multiplication1381860
Ref: da61381860
Ref: whatsnew/3 5 whatsnew-pep-4651381860
Ref: d8e1381860
Ref: PEP 465 - A dedicated infix operator for matrix multiplication-Footnote-11383263
Ref: PEP 465 - A dedicated infix operator for matrix multiplication-Footnote-21383305
Node: PEP 448 - Additional Unpacking Generalizations1383347
Ref: whatsnew/3 5 pep-448-additional-unpacking-generalizations1383586
Ref: daa1383586
Ref: whatsnew/3 5 whatsnew-pep-4481383586
Ref: d8f1383586
Ref: PEP 448 - Additional Unpacking Generalizations-Footnote-11384679
Ref: PEP 448 - Additional Unpacking Generalizations-Footnote-21384721
Node: PEP 461 - percent formatting support for bytes and bytearray1384763
Ref: whatsnew/3 5 pep-461-percent-formatting-support-for-bytes-and-bytearray1384960
Ref: dae1384960
Ref: whatsnew/3 5 whatsnew-pep-4611384960
Ref: d921384960
Ref: PEP 461 - percent formatting support for bytes and bytearray-Footnote-11386496
Ref: PEP 461 - percent formatting support for bytes and bytearray-Footnote-21386538
Node: PEP 484 - Type Hints1386580
Ref: whatsnew/3 5 pep-484-type-hints1386803
Ref: db01386803
Ref: whatsnew/3 5 whatsnew-pep-4841386803
Ref: d901386803
Ref: PEP 484 - Type Hints-Footnote-11388450
Ref: PEP 484 - Type Hints-Footnote-21388492
Ref: PEP 484 - Type Hints-Footnote-31388534
Ref: PEP 484 - Type Hints-Footnote-41388564
Ref: PEP 484 - Type Hints-Footnote-51388606
Node: PEP 471 - os scandir function – a better and faster directory iterator1388648
Ref: whatsnew/3 5 pep-471-os-scandir-function-a-better-and-faster-directory-iterator1388856
Ref: db11388856
Ref: whatsnew/3 5 whatsnew-pep-4711388856
Ref: d9b1388856
Ref: PEP 471 - os scandir function – a better and faster directory iterator-Footnote-11390212
Ref: PEP 471 - os scandir function – a better and faster directory iterator-Footnote-21390254
Node: PEP 475 Retry system calls failing with EINTR1390296
Ref: whatsnew/3 5 pep-475-retry-system-calls-failing-with-eintr1390539
Ref: db31390539
Ref: whatsnew/3 5 whatsnew-pep-4751390539
Ref: db41390539
Ref: PEP 475 Retry system calls failing with EINTR-Footnote-11393603
Ref: PEP 475 Retry system calls failing with EINTR-Footnote-21393645
Node: PEP 479 Change StopIteration handling inside generators1393687
Ref: whatsnew/3 5 pep-479-change-stopiteration-handling-inside-generators1393909
Ref: dda1393909
Ref: whatsnew/3 5 whatsnew-pep-4791393909
Ref: d471393909
Ref: PEP 479 Change StopIteration handling inside generators-Footnote-11395839
Ref: PEP 479 Change StopIteration handling inside generators-Footnote-21395881
Node: PEP 485 A function for testing approximate equality1395923
Ref: whatsnew/3 5 pep-485-a-function-for-testing-approximate-equality1396162
Ref: ddc1396162
Ref: whatsnew/3 5 whatsnew-pep-4851396162
Ref: ddd1396162
Ref: PEP 485 A function for testing approximate equality-Footnote-11397345
Ref: PEP 485 A function for testing approximate equality-Footnote-21397387
Node: PEP 486 Make the Python Launcher aware of virtual environments1397429
Ref: whatsnew/3 5 pep-486-make-the-python-launcher-aware-of-virtual-environments1397645
Ref: de01397645
Ref: whatsnew/3 5 whatsnew-pep-4861397645
Ref: de11397645
Ref: PEP 486 Make the Python Launcher aware of virtual environments-Footnote-11398219
Ref: PEP 486 Make the Python Launcher aware of virtual environments-Footnote-21398261
Ref: PEP 486 Make the Python Launcher aware of virtual environments-Footnote-31398303
Node: PEP 488 Elimination of PYO files1398345
Ref: whatsnew/3 5 pep-488-elimination-of-pyo-files1398561
Ref: de21398561
Ref: whatsnew/3 5 whatsnew-pep-4881398561
Ref: d971398561
Ref: PEP 488 Elimination of PYO files-Footnote-11399416
Ref: PEP 488 Elimination of PYO files-Footnote-21399458
Node: PEP 489 Multi-phase extension module initialization1399500
Ref: whatsnew/3 5 pep-489-multi-phase-extension-module-initialization1399645
Ref: de51399645
Ref: whatsnew/3 5 whatsnew-pep-4891399645
Ref: d981399645
Ref: PEP 489 Multi-phase extension module initialization-Footnote-11400408
Ref: PEP 489 Multi-phase extension module initialization-Footnote-21400450
Ref: PEP 489 Multi-phase extension module initialization-Footnote-31400492
Node: Other Language Changes<9>1400534
Ref: whatsnew/3 5 other-language-changes1400670
Ref: de61400670
Ref: Other Language Changes<9>-Footnote-11401668
Ref: Other Language Changes<9>-Footnote-21401733
Ref: Other Language Changes<9>-Footnote-31401798
Ref: Other Language Changes<9>-Footnote-41401863
Ref: Other Language Changes<9>-Footnote-51401928
Ref: Other Language Changes<9>-Footnote-61401993
Ref: Other Language Changes<9>-Footnote-71402058
Node: New Modules<9>1402123
Ref: whatsnew/3 5 new-modules1402262
Ref: de81402262
Node: typing<10>1402352
Ref: whatsnew/3 5 typing1402431
Ref: de91402431
Node: zipapp<2>1402642
Ref: whatsnew/3 5 whatsnew-zipapp1402721
Ref: d911402721
Ref: whatsnew/3 5 zipapp1402721
Ref: dea1402721
Ref: zipapp<2>-Footnote-11403431
Ref: zipapp<2>-Footnote-21403473
Ref: zipapp<2>-Footnote-31403540
Ref: zipapp<2>-Footnote-41403605
Node: Improved Modules<9>1403647
Ref: whatsnew/3 5 improved-modules1403787
Ref: deb1403787
Node: argparse<4>1405490
Ref: whatsnew/3 5 argparse1405577
Ref: dec1405577
Ref: argparse<4>-Footnote-11405900
Node: asyncio<10>1405965
Ref: whatsnew/3 5 asyncio1406064
Ref: def1406064
Ref: asyncio<10>-Footnote-11409542
Ref: asyncio<10>-Footnote-21409607
Ref: asyncio<10>-Footnote-31409672
Node: bz21409717
Ref: whatsnew/3 5 bz21409808
Ref: df91409808
Ref: bz2-Footnote-11410063
Node: cgi1410128
Ref: whatsnew/3 5 cgi1410216
Ref: dfb1410216
Ref: cgi-Footnote-11410411
Node: cmath<2>1410476
Ref: whatsnew/3 5 cmath1410565
Ref: dfc1410565
Ref: cmath<2>-Footnote-11410779
Node: code1410844
Ref: whatsnew/3 5 code1410944
Ref: dfd1410944
Ref: code-Footnote-11411195
Node: collections<5>1411260
Ref: whatsnew/3 5 collections1411370
Ref: dff1411370
Ref: whatsnew/3 5 whatsnew-ordereddict1411411
Ref: d991411411
Ref: collections<5>-Footnote-11412695
Ref: collections<5>-Footnote-21412760
Ref: collections<5>-Footnote-31412825
Ref: collections<5>-Footnote-41412890
Ref: collections<5>-Footnote-51412955
Node: collections abc<3>1413020
Ref: whatsnew/3 5 collections-abc1413139
Ref: e0a1413139
Ref: collections abc<3>-Footnote-11413809
Ref: collections abc<3>-Footnote-21413874
Ref: collections abc<3>-Footnote-31413939
Ref: collections abc<3>-Footnote-41414004
Node: compileall<4>1414052
Ref: whatsnew/3 5 compileall1414178
Ref: e101414178
Ref: compileall<4>-Footnote-11415053
Ref: compileall<4>-Footnote-21415118
Ref: compileall<4>-Footnote-31415183
Node: concurrent futures<5>1415248
Ref: whatsnew/3 5 concurrent-futures1415371
Ref: e131415371
Ref: concurrent futures<5>-Footnote-11415873
Ref: concurrent futures<5>-Footnote-21415938
Node: configparser<4>1416003
Ref: whatsnew/3 5 configparser1416126
Ref: e151416126
Ref: configparser<4>-Footnote-11417077
Node: contextlib<5>1417142
Ref: whatsnew/3 5 contextlib1417250
Ref: e161417250
Ref: contextlib<5>-Footnote-11417860
Node: csv<3>1417925
Ref: whatsnew/3 5 csv1418027
Ref: e191418027
Ref: csv<3>-Footnote-11418231
Node: curses<4>1418296
Ref: whatsnew/3 5 curses1418391
Ref: e1b1418391
Ref: curses<4>-Footnote-11418679
Node: dbm<5>1418743
Ref: whatsnew/3 5 dbm1418839
Ref: e1f1418839
Ref: dbm<5>-Footnote-11419042
Node: difflib1419107
Ref: whatsnew/3 5 difflib1419206
Ref: e201419206
Ref: difflib-Footnote-11419742
Ref: difflib-Footnote-21419806
Node: distutils<7>1419871
Ref: whatsnew/3 5 distutils1419974
Ref: e231419974
Ref: distutils<7>-Footnote-11420425
Ref: distutils<7>-Footnote-21420489
Node: doctest<3>1420554
Ref: whatsnew/3 5 doctest1420658
Ref: e241420658
Ref: doctest<3>-Footnote-11420943
Node: email<3>1421008
Ref: whatsnew/3 5 email1421107
Ref: e271421107
Ref: email<3>-Footnote-11422218
Ref: email<3>-Footnote-21422283
Ref: email<3>-Footnote-31422348
Ref: email<3>-Footnote-41422407
Ref: email<3>-Footnote-51422466
Ref: email<3>-Footnote-61422531
Node: enum<8>1422596
Ref: whatsnew/3 5 enum1422700
Ref: e2d1422700
Ref: enum<8>-Footnote-11423091
Node: faulthandler<3>1423156
Ref: whatsnew/3 5 faulthandler1423264
Ref: e2e1423264
Ref: faulthandler<3>-Footnote-11423576
Node: functools<4>1423641
Ref: whatsnew/3 5 functools1423749
Ref: e321423749
Ref: whatsnew/3 5 whatsnew-lrucache1423788
Ref: d9c1423788
Ref: functools<4>-Footnote-11424014
Node: glob<3>1424079
Ref: whatsnew/3 5 glob1424179
Ref: e331424179
Ref: glob<3>-Footnote-11424431
Node: gzip<4>1424496
Ref: whatsnew/3 5 gzip1424589
Ref: e341424589
Ref: gzip<4>-Footnote-11424814
Node: heapq1424879
Ref: whatsnew/3 5 heapq1424972
Ref: e351424972
Ref: heapq-Footnote-11425612
Node: http<2>1425677
Ref: whatsnew/3 5 http1425777
Ref: e381425777
Ref: http<2>-Footnote-11426023
Node: http client<3>1426088
Ref: whatsnew/3 5 http-client1426202
Ref: e391426202
Ref: http client<3>-Footnote-11426946
Node: idlelib and IDLE<3>1427010
Ref: whatsnew/3 5 idlelib-and-idle1427127
Ref: e3d1427127
Node: imaplib<2>1427521
Ref: whatsnew/3 5 imaplib1427630
Ref: e3e1427630
Ref: imaplib<2>-Footnote-11428509
Ref: imaplib<2>-Footnote-21428573
Ref: imaplib<2>-Footnote-31428632
Ref: imaplib<2>-Footnote-41428691
Ref: imaplib<2>-Footnote-51428750
Ref: imaplib<2>-Footnote-61428815
Node: imghdr1428880
Ref: whatsnew/3 5 imghdr1428982
Ref: e411428982
Ref: imghdr-Footnote-11429270
Ref: imghdr-Footnote-21429302
Ref: imghdr-Footnote-31429367
Ref: imghdr-Footnote-41429410
Node: importlib<8>1429475
Ref: whatsnew/3 5 importlib1429577
Ref: e421429577
Ref: importlib<8>-Footnote-11430412
Ref: importlib<8>-Footnote-21430477
Ref: importlib<8>-Footnote-31430542
Node: inspect<7>1430607
Ref: whatsnew/3 5 inspect1430708
Ref: e461430708
Ref: inspect<7>-Footnote-11432265
Ref: inspect<7>-Footnote-21432330
Ref: inspect<7>-Footnote-31432395
Ref: inspect<7>-Footnote-41432460
Ref: inspect<7>-Footnote-51432525
Ref: inspect<7>-Footnote-61432590
Ref: inspect<7>-Footnote-71432655
Ref: inspect<7>-Footnote-81432720
Node: io<5>1432785
Ref: whatsnew/3 5 io1432886
Ref: e4c1432886
Ref: io<5>-Footnote-11433184
Node: ipaddress<4>1433249
Ref: whatsnew/3 5 ipaddress1433347
Ref: e501433347
Ref: ipaddress<4>-Footnote-11434381
Ref: ipaddress<4>-Footnote-21434446
Node: json<2>1434511
Ref: whatsnew/3 5 json1434616
Ref: e521434616
Ref: json<2>-Footnote-11435116
Ref: json<2>-Footnote-21435181
Node: linecache<2>1435246
Ref: whatsnew/3 5 linecache1435348
Ref: e541435348
Ref: linecache<2>-Footnote-11435758
Node: locale<6>1435823
Ref: whatsnew/3 5 locale1435928
Ref: e571435928
Ref: locale<6>-Footnote-11436493
Node: logging<5>1436558
Ref: whatsnew/3 5 logging1436655
Ref: e591436655
Ref: logging<5>-Footnote-11437625
Ref: logging<5>-Footnote-21437690
Node: lzma1437755
Ref: whatsnew/3 5 lzma1437850
Ref: e601437850
Ref: lzma-Footnote-11438112
Node: math<8>1438177
Ref: whatsnew/3 5 math1438280
Ref: e621438280
Ref: math<8>-Footnote-11438822
Ref: math<8>-Footnote-21438887
Ref: math<8>-Footnote-31438952
Node: multiprocessing<6>1439017
Ref: whatsnew/3 5 multiprocessing1439127
Ref: e631439127
Ref: multiprocessing<6>-Footnote-11439377
Node: operator<2>1439442
Ref: whatsnew/3 5 operator1439551
Ref: e651439551
Ref: operator<2>-Footnote-11439956
Ref: operator<2>-Footnote-21440021
Node: os<10>1440086
Ref: whatsnew/3 5 os1440188
Ref: e6a1440188
Ref: os<10>-Footnote-11442030
Ref: os<10>-Footnote-21442095
Ref: os<10>-Footnote-31442160
Ref: os<10>-Footnote-41442225
Ref: os<10>-Footnote-51442290
Ref: os<10>-Footnote-61442355
Node: pathlib<10>1442420
Ref: whatsnew/3 5 pathlib1442520
Ref: e721442520
Ref: pathlib<10>-Footnote-11443991
Ref: pathlib<10>-Footnote-21444056
Ref: pathlib<10>-Footnote-31444121
Ref: pathlib<10>-Footnote-41444186
Ref: pathlib<10>-Footnote-51444251
Node: pickle<3>1444316
Ref: whatsnew/3 5 pickle1444419
Ref: e7b1444419
Ref: pickle<3>-Footnote-11444735
Node: poplib<2>1444800
Ref: whatsnew/3 5 poplib1444897
Ref: e7c1444897
Ref: poplib<2>-Footnote-11445139
Ref: poplib<2>-Footnote-21445198
Node: re<7>1445263
Ref: whatsnew/3 5 re1445362
Ref: e7e1445362
Ref: re<7>-Footnote-11446598
Ref: re<7>-Footnote-21446662
Ref: re<7>-Footnote-31446727
Ref: re<7>-Footnote-41446794
Node: readline<2>1446859
Ref: whatsnew/3 5 readline1446958
Ref: e841446958
Ref: readline<2>-Footnote-11447221
Node: selectors1447286
Ref: whatsnew/3 5 selectors1447389
Ref: e861447389
Ref: selectors-Footnote-11447611
Node: shutil<5>1447676
Ref: whatsnew/3 5 shutil1447777
Ref: e871447777
Ref: shutil<5>-Footnote-11448256
Ref: shutil<5>-Footnote-21448321
Node: signal<3>1448385
Ref: whatsnew/3 5 signal1448485
Ref: e881448485
Ref: signal<3>-Footnote-11448952
Ref: signal<3>-Footnote-21449017
Node: smtpd<2>1449082
Ref: whatsnew/3 5 smtpd1449183
Ref: e891449183
Ref: smtpd<2>-Footnote-11450819
Ref: smtpd<2>-Footnote-21450884
Ref: smtpd<2>-Footnote-31450943
Ref: smtpd<2>-Footnote-41451008
Ref: smtpd<2>-Footnote-51451067
Ref: smtpd<2>-Footnote-61451132
Node: smtplib<2>1451197
Ref: whatsnew/3 5 smtplib1451295
Ref: e8a1451295
Ref: smtplib<2>-Footnote-11451916
Ref: smtplib<2>-Footnote-21451981
Ref: smtplib<2>-Footnote-31452046
Ref: smtplib<2>-Footnote-41452105
Node: sndhdr1452170
Ref: whatsnew/3 5 sndhdr1452269
Ref: e8f1452269
Ref: sndhdr-Footnote-11452472
Node: socket<8>1452537
Ref: whatsnew/3 5 socket1452632
Ref: e901452632
Ref: socket<8>-Footnote-11453603
Ref: socket<8>-Footnote-21453668
Ref: socket<8>-Footnote-31453733
Ref: socket<8>-Footnote-41453798
Node: ssl<9>1453863
Ref: whatsnew/3 5 ssl1453962
Ref: e941453962
Node: Memory BIO Support1454091
Ref: whatsnew/3 5 memory-bio-support1454207
Ref: e951454207
Ref: whatsnew/3 5 whatsnew-sslmemorybio1454207
Ref: d9a1454207
Ref: Memory BIO Support-Footnote-11455090
Node: Application-Layer Protocol Negotiation Support1455155
Ref: whatsnew/3 5 application-layer-protocol-negotiation-support1455293
Ref: e971455293
Ref: Application-Layer Protocol Negotiation Support-Footnote-11455998
Ref: Application-Layer Protocol Negotiation Support-Footnote-21456063
Node: Other Changes1456122
Ref: whatsnew/3 5 other-changes1456233
Ref: e9b1456233
Ref: Other Changes-Footnote-11457819
Ref: Other Changes-Footnote-21457884
Ref: Other Changes-Footnote-31457949
Ref: Other Changes-Footnote-41458014
Ref: Other Changes-Footnote-51458073
Ref: Other Changes-Footnote-61458138
Ref: Other Changes-Footnote-71458203
Ref: Other Changes-Footnote-81458268
Node: sqlite3<8>1458333
Ref: whatsnew/3 5 sqlite31458436
Ref: ea41458436
Ref: sqlite3<8>-Footnote-11458765
Ref: sqlite3<8>-Footnote-21458830
Node: subprocess<4>1458895
Ref: whatsnew/3 5 subprocess1458999
Ref: ea61458999
Ref: whatsnew/3 5 whatsnew-subprocess1458999
Ref: d9d1458999
Ref: subprocess<4>-Footnote-11460013
Node: sys<11>1460078
Ref: whatsnew/3 5 sys1460184
Ref: ea81460184
Ref: sys<11>-Footnote-11460834
Ref: sys<11>-Footnote-21460899
Node: sysconfig<2>1460964
Ref: whatsnew/3 5 sysconfig1461067
Ref: ea91461067
Ref: sysconfig<2>-Footnote-11461300
Node: tarfile<7>1461365
Ref: whatsnew/3 5 tarfile1461473
Ref: eaa1461473
Ref: tarfile<7>-Footnote-11462384
Ref: tarfile<7>-Footnote-21462449
Ref: tarfile<7>-Footnote-31462514
Node: threading<6>1462579
Ref: whatsnew/3 5 threading1462682
Ref: eae1462682
Ref: threading<6>-Footnote-11462934
Node: time<7>1462999
Ref: whatsnew/3 5 time1463101
Ref: eb01463101
Ref: time<7>-Footnote-11463278
Node: timeit<2>1463343
Ref: whatsnew/3 5 timeit1463443
Ref: eb11463443
Ref: timeit<2>-Footnote-11463908
Ref: timeit<2>-Footnote-21463973
Node: tkinter<8>1464037
Ref: whatsnew/3 5 tkinter1464142
Ref: eb31464142
Ref: tkinter<8>-Footnote-11464474
Node: traceback<5>1464539
Ref: whatsnew/3 5 traceback1464643
Ref: eb41464643
Ref: whatsnew/3 5 whatsnew-traceback1464643
Ref: d9e1464643
Ref: traceback<5>-Footnote-11465236
Ref: traceback<5>-Footnote-21465301
Ref: traceback<5>-Footnote-31465366
Node: types<5>1465431
Ref: whatsnew/3 5 types1465539
Ref: ebb1465539
Ref: types<5>-Footnote-11465983
Ref: types<5>-Footnote-21466048
Node: unicodedata<8>1466113
Ref: whatsnew/3 5 unicodedata1466220
Ref: ebe1466220
Ref: unicodedata<8>-Footnote-11466372
Node: unittest<8>1466423
Ref: whatsnew/3 5 unittest1466538
Ref: ebf1466538
Ref: unittest<8>-Footnote-11467332
Ref: unittest<8>-Footnote-21467397
Ref: unittest<8>-Footnote-31467462
Node: unittest mock<3>1467527
Ref: whatsnew/3 5 unittest-mock1467637
Ref: ec11467637
Ref: unittest mock<3>-Footnote-11468578
Ref: unittest mock<3>-Footnote-21468643
Ref: unittest mock<3>-Footnote-31468708
Ref: unittest mock<3>-Footnote-41468773
Ref: unittest mock<3>-Footnote-51468838
Ref: unittest mock<3>-Footnote-61468903
Node: urllib<2>1468968
Ref: whatsnew/3 5 urllib1469074
Ref: ec71469074
Ref: urllib<2>-Footnote-11470234
Ref: urllib<2>-Footnote-21470299
Ref: urllib<2>-Footnote-31470363
Ref: urllib<2>-Footnote-41470428
Ref: urllib<2>-Footnote-51470493
Ref: urllib<2>-Footnote-61470552
Ref: urllib<2>-Footnote-71470611
Ref: urllib<2>-Footnote-81470670
Node: wsgiref1470735
Ref: whatsnew/3 5 wsgiref1470834
Ref: ecb1470834
Ref: wsgiref-Footnote-11471072
Node: xmlrpc<2>1471136
Ref: whatsnew/3 5 xmlrpc1471233
Ref: ecd1471233
Ref: xmlrpc<2>-Footnote-11471603
Ref: xmlrpc<2>-Footnote-21471668
Node: xml sax1471733
Ref: whatsnew/3 5 xml-sax1471833
Ref: ece1471833
Ref: xml sax-Footnote-11472166
Ref: xml sax-Footnote-21472230
Node: zipfile<4>1472295
Ref: whatsnew/3 5 zipfile1472377
Ref: ed11472377
Ref: zipfile<4>-Footnote-11472717
Ref: zipfile<4>-Footnote-21472782
Node: Other module-level changes1472847
Ref: whatsnew/3 5 other-module-level-changes1472989
Ref: ed21472989
Ref: Other module-level changes-Footnote-11473316
Node: Optimizations<9>1473381
Ref: whatsnew/3 5 optimizations1473530
Ref: ed31473530
Ref: Optimizations<9>-Footnote-11476587
Ref: Optimizations<9>-Footnote-21476652
Ref: Optimizations<9>-Footnote-31476717
Ref: Optimizations<9>-Footnote-41476782
Ref: Optimizations<9>-Footnote-51476847
Ref: Optimizations<9>-Footnote-61476912
Ref: Optimizations<9>-Footnote-71476977
Ref: Optimizations<9>-Footnote-81477042
Ref: Optimizations<9>-Footnote-91477107
Ref: Optimizations<9>-Footnote-101477172
Ref: Optimizations<9>-Footnote-111477238
Ref: Optimizations<9>-Footnote-121477304
Ref: Optimizations<9>-Footnote-131477370
Ref: Optimizations<9>-Footnote-141477436
Ref: Optimizations<9>-Footnote-151477502
Ref: Optimizations<9>-Footnote-161477568
Ref: Optimizations<9>-Footnote-171477634
Ref: Optimizations<9>-Footnote-181477700
Ref: Optimizations<9>-Footnote-191477766
Ref: Optimizations<9>-Footnote-201477832
Node: Build and C API Changes<3>1477898
Ref: whatsnew/3 5 build-and-c-api-changes1478035
Ref: ee01478035
Ref: Build and C API Changes<3>-Footnote-11481591
Ref: Build and C API Changes<3>-Footnote-21481656
Ref: Build and C API Changes<3>-Footnote-31481721
Ref: Build and C API Changes<3>-Footnote-41481786
Ref: Build and C API Changes<3>-Footnote-51481851
Ref: Build and C API Changes<3>-Footnote-61481916
Ref: Build and C API Changes<3>-Footnote-71481958
Ref: Build and C API Changes<3>-Footnote-81482023
Ref: Build and C API Changes<3>-Footnote-91482088
Ref: Build and C API Changes<3>-Footnote-101482130
Node: Deprecated<10>1482236
Ref: whatsnew/3 5 deprecated1482368
Ref: eec1482368
Node: New Keywords<2>1482645
Ref: whatsnew/3 5 new-keywords1482749
Ref: eed1482749
Ref: New Keywords<2>-Footnote-11483023
Node: Deprecated Python Behavior<2>1483065
Ref: whatsnew/3 5 deprecated-python-behavior1483207
Ref: eee1483207
Node: Unsupported Operating Systems1483622
Ref: whatsnew/3 5 unsupported-operating-systems1483799
Ref: eef1483799
Ref: Unsupported Operating Systems-Footnote-11484040
Node: Deprecated Python modules functions and methods<3>1484082
Ref: whatsnew/3 5 deprecated-python-modules-functions-and-methods1484221
Ref: ef01484221
Ref: Deprecated Python modules functions and methods<3>-Footnote-11487127
Ref: Deprecated Python modules functions and methods<3>-Footnote-21487192
Ref: Deprecated Python modules functions and methods<3>-Footnote-31487256
Ref: Deprecated Python modules functions and methods<3>-Footnote-41487321
Ref: Deprecated Python modules functions and methods<3>-Footnote-51487386
Ref: Deprecated Python modules functions and methods<3>-Footnote-61487451
Ref: Deprecated Python modules functions and methods<3>-Footnote-71487516
Ref: Deprecated Python modules functions and methods<3>-Footnote-81487581
Node: Removed<10>1487646
Ref: whatsnew/3 5 removed1487773
Ref: ef51487773
Node: API and Feature Removals<4>1487871
Ref: whatsnew/3 5 api-and-feature-removals1487946
Ref: ef61487946
Ref: API and Feature Removals<4>-Footnote-11488803
Ref: API and Feature Removals<4>-Footnote-21488867
Node: Porting to Python 3 51488932
Ref: whatsnew/3 5 porting-to-python-3-51489076
Ref: ef71489076
Node: Changes in Python behavior<2>1489421
Ref: whatsnew/3 5 changes-in-python-behavior1489545
Ref: ef81489545
Node: Changes in the Python API<9>1489955
Ref: whatsnew/3 5 changes-in-the-python-api1490111
Ref: ef91490111
Ref: Changes in the Python API<9>-Footnote-11496981
Ref: Changes in the Python API<9>-Footnote-21497023
Ref: Changes in the Python API<9>-Footnote-31497088
Ref: Changes in the Python API<9>-Footnote-41497153
Ref: Changes in the Python API<9>-Footnote-51497218
Ref: Changes in the Python API<9>-Footnote-61497283
Ref: Changes in the Python API<9>-Footnote-71497348
Ref: Changes in the Python API<9>-Footnote-81497413
Ref: Changes in the Python API<9>-Footnote-91497478
Ref: Changes in the Python API<9>-Footnote-101497543
Ref: Changes in the Python API<9>-Footnote-111497609
Ref: Changes in the Python API<9>-Footnote-121497675
Ref: Changes in the Python API<9>-Footnote-131497740
Ref: Changes in the Python API<9>-Footnote-141497783
Ref: Changes in the Python API<9>-Footnote-151497843
Ref: Changes in the Python API<9>-Footnote-161497909
Ref: Changes in the Python API<9>-Footnote-171497975
Ref: Changes in the Python API<9>-Footnote-181498041
Node: Changes in the C API<7>1498106
Ref: whatsnew/3 5 changes-in-the-c-api1498224
Ref: f011498224
Ref: Changes in the C API<7>-Footnote-11499522
Ref: Changes in the C API<7>-Footnote-21499587
Ref: Changes in the C API<7>-Footnote-31499652
Node: Notable changes in Python 3 5 41499694
Ref: whatsnew/3 5 notable-changes-in-python-3-5-41499818
Ref: f051499818
Node: New make regen-all build target<2>1500055
Ref: whatsnew/3 5 new-make-regen-all-build-target1500203
Ref: f061500203
Ref: New make regen-all build target<2>-Footnote-11500992
Ref: New make regen-all build target<2>-Footnote-21501060
Node: Removal of make touch build target<2>1501125
Ref: whatsnew/3 5 removal-of-make-touch-build-target1501273
Ref: f071501273
Ref: Removal of make touch build target<2>-Footnote-11501703
Node: What’s New In Python 3 41501768
Ref: whatsnew/3 4 doc1501923
Ref: f081501923
Ref: whatsnew/3 4 translation-repo1501923
Ref: f091501923
Ref: whatsnew/3 4 what-s-new-in-python-3-41501923
Ref: f0a1501923
Ref: What’s New In Python 3 4-Footnote-11502664
Ref: What’s New In Python 3 4-Footnote-21502724
Node: Summary – Release Highlights<3>1502766
Ref: whatsnew/3 4 summary-release-highlights1502887
Ref: f0b1502887
Ref: Summary – Release Highlights<3>-Footnote-11507184
Ref: Summary – Release Highlights<3>-Footnote-21507226
Ref: Summary – Release Highlights<3>-Footnote-31507268
Ref: Summary – Release Highlights<3>-Footnote-41507333
Ref: Summary – Release Highlights<3>-Footnote-51507375
Ref: Summary – Release Highlights<3>-Footnote-61507440
Ref: Summary – Release Highlights<3>-Footnote-71507482
Ref: Summary – Release Highlights<3>-Footnote-81507524
Ref: Summary – Release Highlights<3>-Footnote-91507566
Ref: Summary – Release Highlights<3>-Footnote-101507608
Ref: Summary – Release Highlights<3>-Footnote-111507651
Ref: Summary – Release Highlights<3>-Footnote-121507694
Ref: Summary – Release Highlights<3>-Footnote-131507737
Ref: Summary – Release Highlights<3>-Footnote-141507780
Ref: Summary – Release Highlights<3>-Footnote-151507823
Ref: Summary – Release Highlights<3>-Footnote-161507888
Ref: Summary – Release Highlights<3>-Footnote-171507954
Ref: Summary – Release Highlights<3>-Footnote-181507997
Ref: Summary – Release Highlights<3>-Footnote-191508040
Ref: Summary – Release Highlights<3>-Footnote-201508106
Ref: Summary – Release Highlights<3>-Footnote-211508152
Ref: Summary – Release Highlights<3>-Footnote-221508195
Ref: Summary – Release Highlights<3>-Footnote-231508238
Ref: Summary – Release Highlights<3>-Footnote-241508304
Ref: Summary – Release Highlights<3>-Footnote-251508347
Node: New Features<15>1508390
Ref: whatsnew/3 4 new-features1508535
Ref: f261508535
Node: PEP 453 Explicit Bootstrapping of PIP in Python Installations1509028
Ref: whatsnew/3 4 pep-453-explicit-bootstrapping-of-pip-in-python-installations1509209
Ref: f271509209
Ref: whatsnew/3 4 whatsnew-pep-4531509209
Ref: f0c1509209
Node: Bootstrapping pip By Default1509423
Ref: whatsnew/3 4 bootstrapping-pip-by-default1509579
Ref: f281509579
Ref: Bootstrapping pip By Default-Footnote-11512474
Ref: Bootstrapping pip By Default-Footnote-21512516
Node: Documentation Changes1512603
Ref: whatsnew/3 4 documentation-changes1512759
Ref: f2b1512759
Ref: Documentation Changes-Footnote-11513695
Ref: Documentation Changes-Footnote-21513732
Node: PEP 446 Newly Created File Descriptors Are Non-Inheritable1513774
Ref: whatsnew/3 4 pep-446-newly-created-file-descriptors-are-non-inheritable1513994
Ref: f2f1513994
Ref: whatsnew/3 4 whatsnew-pep-4461513994
Ref: f0d1513994
Ref: PEP 446 Newly Created File Descriptors Are Non-Inheritable-Footnote-11515014
Ref: PEP 446 Newly Created File Descriptors Are Non-Inheritable-Footnote-21515056
Node: Improvements to Codec Handling1515098
Ref: whatsnew/3 4 codec-handling-improvements1515304
Ref: f0f1515304
Ref: whatsnew/3 4 improvements-to-codec-handling1515304
Ref: f371515304
Ref: Improvements to Codec Handling-Footnote-11519512
Ref: Improvements to Codec Handling-Footnote-21519576
Ref: Improvements to Codec Handling-Footnote-31519641
Ref: Improvements to Codec Handling-Footnote-41519706
Node: PEP 451 A ModuleSpec Type for the Import System1519771
Ref: whatsnew/3 4 pep-451-a-modulespec-type-for-the-import-system1519945
Ref: f3c1519945
Ref: whatsnew/3 4 whatsnew-pep-4511519945
Ref: f101519945
Ref: PEP 451 A ModuleSpec Type for the Import System-Footnote-11520898
Ref: PEP 451 A ModuleSpec Type for the Import System-Footnote-21520940
Node: Other Language Changes<10>1521020
Ref: whatsnew/3 4 other-language-changes1521155
Ref: f3e1521155
Ref: Other Language Changes<10>-Footnote-11523799
Ref: Other Language Changes<10>-Footnote-21523864
Ref: Other Language Changes<10>-Footnote-31523929
Ref: Other Language Changes<10>-Footnote-41523994
Ref: Other Language Changes<10>-Footnote-51524061
Ref: Other Language Changes<10>-Footnote-61524126
Ref: Other Language Changes<10>-Footnote-71524191
Ref: Other Language Changes<10>-Footnote-81524256
Ref: Other Language Changes<10>-Footnote-91524321
Ref: Other Language Changes<10>-Footnote-101524386
Ref: Other Language Changes<10>-Footnote-111524452
Ref: Other Language Changes<10>-Footnote-121524495
Node: New Modules<10>1524561
Ref: whatsnew/3 4 new-modules1524693
Ref: f431524693
Node: asyncio<11>1524921
Ref: whatsnew/3 4 asyncio1525005
Ref: f441525005
Ref: whatsnew/3 4 whatsnew-asyncio1525005
Ref: f121525005
Ref: asyncio<11>-Footnote-11525605
Ref: asyncio<11>-Footnote-21525647
Node: ensurepip<2>1525689
Ref: whatsnew/3 4 ensurepip1525789
Ref: f451525789
Ref: whatsnew/3 4 whatsnew-ensurepip1525789
Ref: f131525789
Ref: ensurepip<2>-Footnote-11527063
Node: enum<9>1527105
Ref: whatsnew/3 4 enum1527205
Ref: f461527205
Ref: whatsnew/3 4 whatsnew-enum1527205
Ref: f141527205
Ref: enum<9>-Footnote-11527777
Ref: enum<9>-Footnote-21527819
Node: pathlib<11>1527861
Ref: whatsnew/3 4 pathlib1527961
Ref: f471527961
Ref: whatsnew/3 4 whatsnew-pathlib1527961
Ref: f151527961
Ref: pathlib<11>-Footnote-11528581
Node: selectors<2>1528623
Ref: whatsnew/3 4 selectors1528729
Ref: f481528729
Ref: whatsnew/3 4 whatsnew-selectors1528729
Ref: f161528729
Ref: selectors<2>-Footnote-11528989
Node: statistics<6>1529031
Ref: whatsnew/3 4 statistics1529140
Ref: f491529140
Ref: whatsnew/3 4 whatsnew-statistics1529140
Ref: f171529140
Ref: statistics<6>-Footnote-11529607
Ref: statistics<6>-Footnote-21529649
Node: tracemalloc<4>1529691
Ref: whatsnew/3 4 tracemalloc1529779
Ref: f4a1529779
Ref: whatsnew/3 4 whatsnew-tracemalloc1529779
Ref: f181529779
Ref: tracemalloc<4>-Footnote-11530445
Ref: tracemalloc<4>-Footnote-21530487
Node: Improved Modules<10>1530529
Ref: whatsnew/3 4 improved-modules1530675
Ref: f4b1530675
Node: abc1532023
Ref: whatsnew/3 4 abc1532099
Ref: f4c1532099
Ref: abc-Footnote-11532622
Ref: abc-Footnote-21532687
Node: aifc<2>1532752
Ref: whatsnew/3 4 aifc1532848
Ref: f501532848
Ref: aifc<2>-Footnote-11533458
Ref: aifc<2>-Footnote-21533523
Ref: aifc<2>-Footnote-31533588
Node: argparse<5>1533652
Ref: whatsnew/3 4 argparse1533752
Ref: f511533752
Ref: argparse<5>-Footnote-11534000
Node: audioop1534065
Ref: whatsnew/3 4 audioop1534167
Ref: f531534167
Ref: audioop-Footnote-11534693
Ref: audioop-Footnote-21534758
Ref: audioop-Footnote-31534823
Node: base64<3>1534888
Ref: whatsnew/3 4 base641534993
Ref: f541534993
Ref: base64<3>-Footnote-11535826
Ref: base64<3>-Footnote-21535891
Node: collections<6>1535956
Ref: whatsnew/3 4 collections1536062
Ref: f591536062
Ref: collections<6>-Footnote-11536394
Node: colorsys1536459
Ref: whatsnew/3 4 colorsys1536569
Ref: f5b1536569
Ref: colorsys-Footnote-11536939
Node: contextlib<6>1537004
Ref: whatsnew/3 4 contextlib1537106
Ref: f5c1537106
Ref: contextlib<6>-Footnote-11538282
Ref: contextlib<6>-Footnote-21538347
Ref: contextlib<6>-Footnote-31538412
Node: dbm<6>1538477
Ref: whatsnew/3 4 dbm1538577
Ref: f601538577
Ref: dbm<6>-Footnote-11538926
Node: dis<4>1538991
Ref: whatsnew/3 4 dis1539088
Ref: f621539088
Ref: dis<4>-Footnote-11541690
Ref: dis<4>-Footnote-21541755
Ref: dis<4>-Footnote-31541820
Node: doctest<4>1541885
Ref: whatsnew/3 4 doctest1541984
Ref: f6a1541984
Ref: doctest<4>-Footnote-11542754
Ref: doctest<4>-Footnote-21542819
Ref: doctest<4>-Footnote-31542884
Node: email<4>1542948
Ref: whatsnew/3 4 email1543048
Ref: f6d1543048
Ref: whatsnew/3 4 whatsnew-email-contentmanager1544298
Ref: f1c1544298
Ref: email<4>-Footnote-11545222
Ref: email<4>-Footnote-21545287
Ref: email<4>-Footnote-31545352
Ref: email<4>-Footnote-41545417
Node: filecmp1545482
Ref: whatsnew/3 4 filecmp1545584
Ref: f751545584
Ref: filecmp-Footnote-11546332
Ref: filecmp-Footnote-21546397
Node: functools<5>1546462
Ref: whatsnew/3 4 functools1546561
Ref: f791546561
Ref: whatsnew/3 4 whatsnew-singledispatch1547004
Ref: f191547004
Ref: functools<5>-Footnote-11547963
Ref: functools<5>-Footnote-21548027
Ref: functools<5>-Footnote-31548069
Ref: functools<5>-Footnote-41548134
Node: gc<5>1548199
Ref: whatsnew/3 4 gc1548298
Ref: f7b1548298
Ref: gc<5>-Footnote-11548566
Node: glob<4>1548631
Ref: whatsnew/3 4 glob1548728
Ref: f7d1548728
Ref: glob<4>-Footnote-11549034
Node: hashlib<6>1549098
Ref: whatsnew/3 4 hashlib1549197
Ref: f7f1549197
Ref: hashlib<6>-Footnote-11549827
Ref: hashlib<6>-Footnote-21549872
Ref: hashlib<6>-Footnote-31549937
Node: hmac<3>1550002
Ref: whatsnew/3 4 hmac1550098
Ref: f811550098
Ref: hmac<3>-Footnote-11551120
Ref: hmac<3>-Footnote-21551185
Ref: hmac<3>-Footnote-31551250
Ref: hmac<3>-Footnote-41551292
Node: html1551357
Ref: whatsnew/3 4 html1551450
Ref: f861551450
Ref: html-Footnote-11552209
Ref: html-Footnote-21552273
Ref: html-Footnote-31552338
Node: http<3>1552403
Ref: whatsnew/3 4 http1552508
Ref: f871552508
Ref: http<3>-Footnote-11553157
Ref: http<3>-Footnote-21553222
Node: idlelib and IDLE<4>1553287
Ref: whatsnew/3 4 idlelib-and-idle1553400
Ref: f8b1553400
Node: importlib<9>1553796
Ref: whatsnew/3 4 importlib1553912
Ref: f8c1553912
Ref: importlib<9>-Footnote-11555896
Ref: importlib<9>-Footnote-21555961
Ref: importlib<9>-Footnote-31556026
Ref: importlib<9>-Footnote-41556091
Ref: importlib<9>-Footnote-51556156
Ref: importlib<9>-Footnote-61556221
Ref: importlib<9>-Footnote-71556286
Node: inspect<8>1556351
Ref: whatsnew/3 4 inspect1556460
Ref: f931556460
Ref: inspect<8>-Footnote-11558158
Ref: inspect<8>-Footnote-21558223
Ref: inspect<8>-Footnote-31558288
Ref: inspect<8>-Footnote-41558353
Ref: inspect<8>-Footnote-51558418
Ref: inspect<8>-Footnote-61558483
Node: ipaddress<5>1558548
Ref: whatsnew/3 4 ipaddress1558655
Ref: f971558655
Ref: ipaddress<5>-Footnote-11559178
Node: logging<6>1559243
Ref: whatsnew/3 4 logging1559350
Ref: f991559350
Ref: logging<6>-Footnote-11560477
Ref: logging<6>-Footnote-21560541
Ref: logging<6>-Footnote-31560606
Node: marshal<2>1560671
Ref: whatsnew/3 4 marshal1560773
Ref: f9f1560773
Ref: whatsnew/3 4 whatsnew-marshal-31560773
Ref: f111560773
Ref: marshal<2>-Footnote-11561454
Ref: marshal<2>-Footnote-21561519
Node: mmap<3>1561584
Ref: whatsnew/3 4 mmap1561694
Ref: fa01561694
Ref: mmap<3>-Footnote-11561866
Node: multiprocessing<7>1561930
Ref: whatsnew/3 4 multiprocessing1562041
Ref: fa11562041
Ref: whatsnew/3 4 whatsnew-multiprocessing-no-fork1562094
Ref: f1b1562094
Ref: multiprocessing<7>-Footnote-11563901
Ref: multiprocessing<7>-Footnote-21563965
Ref: multiprocessing<7>-Footnote-31564030
Ref: multiprocessing<7>-Footnote-41564094
Node: operator<3>1564159
Ref: whatsnew/3 4 operator1564269
Ref: fa51564269
Ref: operator<3>-Footnote-11564822
Ref: operator<3>-Footnote-21564864
Ref: operator<3>-Footnote-31564929
Node: os<11>1564994
Ref: whatsnew/3 4 os1565092
Ref: fa71565092
Ref: os<11>-Footnote-11566539
Ref: os<11>-Footnote-21566604
Ref: os<11>-Footnote-31566669
Ref: os<11>-Footnote-41566733
Node: pdb<6>1566798
Ref: whatsnew/3 4 pdb1566894
Ref: fad1566894
Ref: pdb<6>-Footnote-11567890
Ref: pdb<6>-Footnote-21567955
Node: pickle<4>1568020
Ref: whatsnew/3 4 pickle1568121
Ref: fb01568121
Ref: whatsnew/3 4 whatsnew-protocol-41568121
Ref: f1a1568121
Ref: pickle<4>-Footnote-11568718
Node: plistlib<2>1568760
Ref: whatsnew/3 4 plistlib1568864
Ref: fb11568864
Ref: plistlib<2>-Footnote-11569400
Node: poplib<3>1569465
Ref: whatsnew/3 4 poplib1569569
Ref: fb41569569
Ref: poplib<3>-Footnote-11569959
Node: pprint<4>1570023
Ref: whatsnew/3 4 pprint1570119
Ref: fb71570119
Ref: pprint<4>-Footnote-11570739
Ref: pprint<4>-Footnote-21570804
Node: pty1570869
Ref: whatsnew/3 4 pty1570964
Ref: fba1570964
Node: pydoc<4>1571157
Ref: whatsnew/3 4 pydoc1571248
Ref: fbc1571248
Ref: pydoc<4>-Footnote-11572300
Ref: pydoc<4>-Footnote-21572365
Node: re<8>1572430
Ref: whatsnew/3 4 re1572526
Ref: fbd1572526
Ref: re<8>-Footnote-11573277
Ref: re<8>-Footnote-21573342
Ref: re<8>-Footnote-31573407
Node: resource1573472
Ref: whatsnew/3 4 resource1573566
Ref: fc21573566
Ref: resource-Footnote-11574419
Ref: resource-Footnote-21574484
Ref: resource-Footnote-31574549
Node: select1574614
Ref: whatsnew/3 4 select1574712
Ref: fcc1574712
Ref: select-Footnote-11575221
Ref: select-Footnote-21575286
Node: shelve<2>1575351
Ref: whatsnew/3 4 shelve1575450
Ref: fd31575450
Ref: shelve<2>-Footnote-11575722
Node: shutil<6>1575787
Ref: whatsnew/3 4 shutil1575888
Ref: fd51575888
Ref: shutil<6>-Footnote-11576261
Node: smtpd<3>1576328
Ref: whatsnew/3 4 smtpd1576430
Ref: fd81576430
Ref: smtpd<3>-Footnote-11576790
Node: smtplib<3>1576855
Ref: whatsnew/3 4 smtplib1576957
Ref: fd91576957
Ref: smtplib<3>-Footnote-11577319
Node: socket<9>1577383
Ref: whatsnew/3 4 socket1577487
Ref: fdb1577487
Ref: socket<9>-Footnote-11578270
Ref: socket<9>-Footnote-21578335
Node: sqlite3<9>1578399
Ref: whatsnew/3 4 sqlite31578500
Ref: fdf1578500
Ref: sqlite3<9>-Footnote-11578791
Ref: sqlite3<9>-Footnote-21578831
Node: ssl<10>1578896
Ref: whatsnew/3 4 ssl1578992
Ref: fe01578992
Ref: whatsnew/3 4 whatsnew-tls-11-121579021
Ref: f1e1579021
Ref: whatsnew/3 4 whatsnew34-sslcontext1579291
Ref: f211579291
Ref: whatsnew/3 4 whatsnew34-win-cert-store1581947
Ref: f1f1581947
Ref: whatsnew/3 4 whatsnew34-sni1582201
Ref: f201582201
Ref: ssl<10>-Footnote-11582650
Ref: ssl<10>-Footnote-21582715
Ref: ssl<10>-Footnote-31582780
Ref: ssl<10>-Footnote-41582845
Ref: ssl<10>-Footnote-51582910
Ref: ssl<10>-Footnote-61582975
Ref: ssl<10>-Footnote-71583039
Ref: ssl<10>-Footnote-81583104
Ref: ssl<10>-Footnote-91583169
Ref: ssl<10>-Footnote-101583233
Node: stat1583299
Ref: whatsnew/3 4 stat1583394
Ref: ff21583394
Ref: stat-Footnote-11583867
Ref: stat-Footnote-21583932
Node: struct<2>1583997
Ref: whatsnew/3 4 struct1584098
Ref: ff71584098
Ref: struct<2>-Footnote-11584430
Node: subprocess<5>1584495
Ref: whatsnew/3 4 subprocess1584600
Ref: ffa1584600
Ref: subprocess<5>-Footnote-11585052
Ref: subprocess<5>-Footnote-21585117
Node: sunau<2>1585182
Ref: whatsnew/3 4 sunau1585285
Ref: ffe1585285
Ref: sunau<2>-Footnote-11586069
Ref: sunau<2>-Footnote-21586134
Ref: sunau<2>-Footnote-31586199
Ref: sunau<2>-Footnote-41586264
Node: sys<12>1586328
Ref: whatsnew/3 4 sys1586428
Ref: fff1586428
Ref: sys<12>-Footnote-11587712
Ref: sys<12>-Footnote-21587777
Node: tarfile<8>1587841
Ref: whatsnew/3 4 tarfile1587941
Ref: 10051587941
Ref: tarfile<8>-Footnote-11588260
Node: textwrap1588325
Ref: whatsnew/3 4 textwrap1588430
Ref: 10071588430
Ref: textwrap-Footnote-11589135
Ref: textwrap-Footnote-21589200
Node: threading<7>1589265
Ref: whatsnew/3 4 threading1589372
Ref: 100c1589372
Ref: threading<7>-Footnote-11589718
Node: traceback<6>1589783
Ref: whatsnew/3 4 traceback1589890
Ref: 100e1589890
Ref: traceback<6>-Footnote-11590206
Node: types<6>1590273
Ref: whatsnew/3 4 types1590377
Ref: 10101590377
Ref: types<6>-Footnote-11590888
Node: urllib<3>1590953
Ref: whatsnew/3 4 urllib1591056
Ref: 10111591056
Ref: urllib<3>-Footnote-11592365
Ref: urllib<3>-Footnote-21592430
Ref: urllib<3>-Footnote-31592495
Ref: urllib<3>-Footnote-41592560
Ref: urllib<3>-Footnote-51592625
Ref: urllib<3>-Footnote-61592690
Node: unittest<9>1592755
Ref: whatsnew/3 4 unittest1592857
Ref: 101b1592857
Ref: unittest<9>-Footnote-11596021
Ref: unittest<9>-Footnote-21596086
Ref: unittest<9>-Footnote-31596151
Ref: unittest<9>-Footnote-41596216
Ref: unittest<9>-Footnote-51596281
Ref: unittest<9>-Footnote-61596346
Ref: unittest<9>-Footnote-71596411
Ref: unittest<9>-Footnote-81596476
Ref: unittest<9>-Footnote-91596541
Node: venv<7>1596606
Ref: whatsnew/3 4 venv1596706
Ref: 10231596706
Ref: venv<7>-Footnote-11597258
Ref: venv<7>-Footnote-21597323
Ref: venv<7>-Footnote-31597388
Node: wave<2>1597430
Ref: whatsnew/3 4 wave1597529
Ref: 10241597529
Ref: wave<2>-Footnote-11598176
Ref: wave<2>-Footnote-21598241
Ref: wave<2>-Footnote-31598306
Ref: wave<2>-Footnote-41598370
Node: weakref<2>1598434
Ref: whatsnew/3 4 weakref1598538
Ref: 10291598538
Ref: weakref<2>-Footnote-11599162
Ref: weakref<2>-Footnote-21599227
Ref: weakref<2>-Footnote-31599292
Node: xml etree<2>1599357
Ref: whatsnew/3 4 xml-etree1599464
Ref: 102d1599464
Ref: xml etree<2>-Footnote-11600207
Ref: xml etree<2>-Footnote-21600272
Node: zipfile<5>1600337
Ref: whatsnew/3 4 zipfile1600425
Ref: 10321600425
Ref: zipfile<5>-Footnote-11600965
Ref: zipfile<5>-Footnote-21601030
Node: CPython Implementation Changes1601095
Ref: whatsnew/3 4 cpython-implementation-changes1601240
Ref: 10351601240
Node: PEP 445 Customization of CPython Memory Allocators1601772
Ref: whatsnew/3 4 pep-445-customization-of-cpython-memory-allocators1601930
Ref: 10361601930
Ref: whatsnew/3 4 whatsnew-pep-4451601930
Ref: f241601930
Ref: PEP 445 Customization of CPython Memory Allocators-Footnote-11602327
Ref: PEP 445 Customization of CPython Memory Allocators-Footnote-21602369
Node: PEP 442 Safe Object Finalization1602411
Ref: whatsnew/3 4 pep-442-safe-object-finalization1602627
Ref: 10371602627
Ref: whatsnew/3 4 whatsnew-pep-4421602627
Ref: f231602627
Ref: PEP 442 Safe Object Finalization-Footnote-11603497
Ref: PEP 442 Safe Object Finalization-Footnote-21603539
Node: PEP 456 Secure and Interchangeable Hash Algorithm1603581
Ref: whatsnew/3 4 pep-456-secure-and-interchangeable-hash-algorithm1603770
Ref: 10391603770
Ref: whatsnew/3 4 whatsnew-pep-4561603770
Ref: f1d1603770
Ref: PEP 456 Secure and Interchangeable Hash Algorithm-Footnote-11604719
Ref: PEP 456 Secure and Interchangeable Hash Algorithm-Footnote-21604761
Node: PEP 436 Argument Clinic1604826
Ref: whatsnew/3 4 pep-436-argument-clinic1605012
Ref: 103b1605012
Ref: whatsnew/3 4 whatsnew-pep-4361605012
Ref: f251605012
Ref: PEP 436 Argument Clinic-Footnote-11606120
Ref: PEP 436 Argument Clinic-Footnote-21606162
Node: Other Build and C API Changes1606204
Ref: whatsnew/3 4 other-build-and-c-api-changes1606362
Ref: 103c1606362
Ref: Other Build and C API Changes-Footnote-11608449
Ref: Other Build and C API Changes-Footnote-21608514
Ref: Other Build and C API Changes-Footnote-31608579
Ref: Other Build and C API Changes-Footnote-41608646
Ref: Other Build and C API Changes-Footnote-51608710
Ref: Other Build and C API Changes-Footnote-61608775
Ref: Other Build and C API Changes-Footnote-71608848
Ref: Other Build and C API Changes-Footnote-81608912
Ref: Other Build and C API Changes-Footnote-91608977
Node: Other Improvements<2>1609042
Ref: whatsnew/3 4 other-improvements1609202
Ref: 10401609202
Ref: whatsnew/3 4 other-improvements-3-41609202
Ref: 10411609202
Ref: whatsnew/3 4 whatsnew-isolated-mode1609259
Ref: f0e1609259
Ref: Other Improvements<2>-Footnote-11613384
Ref: Other Improvements<2>-Footnote-21613449
Ref: Other Improvements<2>-Footnote-31613513
Ref: Other Improvements<2>-Footnote-41613578
Ref: Other Improvements<2>-Footnote-51613643
Ref: Other Improvements<2>-Footnote-61613708
Ref: Other Improvements<2>-Footnote-71613773
Ref: Other Improvements<2>-Footnote-81613868
Ref: Other Improvements<2>-Footnote-91613919
Ref: Other Improvements<2>-Footnote-101613984
Ref: Other Improvements<2>-Footnote-111614050
Ref: Other Improvements<2>-Footnote-121614116
Ref: Other Improvements<2>-Footnote-131614159
Ref: Other Improvements<2>-Footnote-141614225
Ref: Other Improvements<2>-Footnote-151614291
Ref: Other Improvements<2>-Footnote-161614357
Ref: Other Improvements<2>-Footnote-171614423
Ref: Other Improvements<2>-Footnote-181614466
Ref: Other Improvements<2>-Footnote-191614532
Ref: Other Improvements<2>-Footnote-201614598
Ref: Other Improvements<2>-Footnote-211614664
Node: Significant Optimizations1614730
Ref: whatsnew/3 4 significant-optimizations1614852
Ref: 10461614852
Ref: Significant Optimizations-Footnote-11617660
Ref: Significant Optimizations-Footnote-21617725
Ref: Significant Optimizations-Footnote-31617790
Ref: Significant Optimizations-Footnote-41617855
Ref: Significant Optimizations-Footnote-51617920
Ref: Significant Optimizations-Footnote-61617985
Ref: Significant Optimizations-Footnote-71618050
Ref: Significant Optimizations-Footnote-81618114
Ref: Significant Optimizations-Footnote-91618179
Ref: Significant Optimizations-Footnote-101618244
Ref: Significant Optimizations-Footnote-111618310
Ref: Significant Optimizations-Footnote-121618376
Ref: Significant Optimizations-Footnote-131618442
Node: Deprecated<11>1618508
Ref: whatsnew/3 4 deprecated1618644
Ref: 104a1618644
Ref: whatsnew/3 4 deprecated-3-41618644
Ref: f3d1618644
Node: Deprecations in the Python API1619086
Ref: whatsnew/3 4 deprecations-in-the-python-api1619195
Ref: 104b1619195
Node: Deprecated Features1622843
Ref: whatsnew/3 4 deprecated-features1622952
Ref: 104f1622952
Ref: Deprecated Features-Footnote-11623366
Ref: Deprecated Features-Footnote-21623431
Node: Removed<11>1623496
Ref: whatsnew/3 4 removed1623623
Ref: 10511623623
Node: Operating Systems No Longer Supported1623781
Ref: whatsnew/3 4 operating-systems-no-longer-supported1623902
Ref: 10521623902
Ref: Operating Systems No Longer Supported-Footnote-11624317
Ref: Operating Systems No Longer Supported-Footnote-21624382
Ref: Operating Systems No Longer Supported-Footnote-31624447
Node: API and Feature Removals<5>1624512
Ref: whatsnew/3 4 api-and-feature-removals1624655
Ref: 10531624655
Ref: API and Feature Removals<5>-Footnote-11627107
Ref: API and Feature Removals<5>-Footnote-21627143
Ref: API and Feature Removals<5>-Footnote-31627208
Ref: API and Feature Removals<5>-Footnote-41627273
Ref: API and Feature Removals<5>-Footnote-51627338
Ref: API and Feature Removals<5>-Footnote-61627403
Ref: API and Feature Removals<5>-Footnote-71627467
Node: Code Cleanups1627532
Ref: whatsnew/3 4 code-cleanups1627629
Ref: 10551627629
Ref: Code Cleanups-Footnote-11628293
Node: Porting to Python 3 41628358
Ref: whatsnew/3 4 porting-to-python-3-41628487
Ref: 10561628487
Node: Changes in ‘python’ Command Behavior<2>1628861
Ref: whatsnew/3 4 changes-in-python-command-behavior1629000
Ref: 10571629000
Ref: Changes in ‘python’ Command Behavior<2>-Footnote-11630109
Node: Changes in the Python API<10>1630174
Ref: whatsnew/3 4 changes-in-the-python-api1630345
Ref: 10591630345
Ref: Changes in the Python API<10>-Footnote-11643678
Ref: Changes in the Python API<10>-Footnote-21643743
Ref: Changes in the Python API<10>-Footnote-31643808
Ref: Changes in the Python API<10>-Footnote-41643873
Ref: Changes in the Python API<10>-Footnote-51643938
Ref: Changes in the Python API<10>-Footnote-61644003
Ref: Changes in the Python API<10>-Footnote-71644068
Ref: Changes in the Python API<10>-Footnote-81644133
Ref: Changes in the Python API<10>-Footnote-91644197
Ref: Changes in the Python API<10>-Footnote-101644262
Ref: Changes in the Python API<10>-Footnote-111644328
Ref: Changes in the Python API<10>-Footnote-121644394
Ref: Changes in the Python API<10>-Footnote-131644460
Ref: Changes in the Python API<10>-Footnote-141644526
Ref: Changes in the Python API<10>-Footnote-151644592
Ref: Changes in the Python API<10>-Footnote-161644658
Ref: Changes in the Python API<10>-Footnote-171644724
Ref: Changes in the Python API<10>-Footnote-181644790
Ref: Changes in the Python API<10>-Footnote-191644856
Ref: Changes in the Python API<10>-Footnote-201644922
Ref: Changes in the Python API<10>-Footnote-211644988
Ref: Changes in the Python API<10>-Footnote-221645054
Ref: Changes in the Python API<10>-Footnote-231645120
Ref: Changes in the Python API<10>-Footnote-241645185
Node: Changes in the C API<8>1645251
Ref: whatsnew/3 4 changes-in-the-c-api1645370
Ref: 106a1645370
Ref: Changes in the C API<8>-Footnote-11647137
Ref: Changes in the C API<8>-Footnote-21647202
Node: Changed in 3 4 31647267
Ref: whatsnew/3 4 changed-in-3-4-31647376
Ref: 10701647376
Node: PEP 476 Enabling certificate verification by default for stdlib http clients1647594
Ref: whatsnew/3 4 pep-4761647723
Ref: 10711647723
Ref: whatsnew/3 4 pep-476-enabling-certificate-verification-by-default-for-stdlib-http-clients1647723
Ref: 10721647723
Node: What’s New In Python 3 31648724
Ref: whatsnew/3 3 doc1648879
Ref: 10731648879
Ref: whatsnew/3 3 translation-repo1648879
Ref: 10741648879
Ref: whatsnew/3 3 what-s-new-in-python-3-31648879
Ref: 10751648879
Ref: What’s New In Python 3 3-Footnote-11650826
Ref: What’s New In Python 3 3-Footnote-21650886
Node: Summary – Release highlights<8>1650928
Ref: whatsnew/3 3 summary-release-highlights1651061
Ref: 10761651061
Node: PEP 405 Virtual Environments1652401
Ref: whatsnew/3 3 pep-4051652578
Ref: 10781652578
Ref: whatsnew/3 3 pep-405-virtual-environments1652578
Ref: 10801652578
Ref: PEP 405 Virtual Environments-Footnote-11653568
Node: PEP 420 Implicit Namespace Packages1653610
Ref: whatsnew/3 3 pep-420-implicit-namespace-packages1653826
Ref: 10811653826
Ref: PEP 420 Implicit Namespace Packages-Footnote-11654339
Ref: PEP 420 Implicit Namespace Packages-Footnote-21654381
Node: PEP 3118 New memoryview implementation and buffer protocol documentation1654423
Ref: whatsnew/3 3 pep-3118-new-memoryview-implementation-and-buffer-protocol-documentation1654649
Ref: 10821654649
Ref: whatsnew/3 3 pep-3118-update1654649
Ref: 10831654649
Ref: PEP 3118 New memoryview implementation and buffer protocol documentation-Footnote-11655781
Node: Features1655823
Ref: whatsnew/3 3 features1655960
Ref: 10841655960
Ref: Features-Footnote-11656764
Node: API changes1656829
Ref: whatsnew/3 3 api-changes1656966
Ref: 10851656966
Ref: API changes-Footnote-11657985
Ref: API changes-Footnote-21658050
Node: PEP 393 Flexible String Representation1658092
Ref: whatsnew/3 3 pep-3931658318
Ref: 107b1658318
Ref: whatsnew/3 3 pep-393-flexible-string-representation1658318
Ref: 10881658318
Ref: PEP 393 Flexible String Representation-Footnote-11659379
Node: Functionality1659421
Ref: whatsnew/3 3 functionality1659548
Ref: 10891659548
Ref: Functionality-Footnote-11660998
Ref: Functionality-Footnote-21661040
Node: Performance and resource usage1661105
Ref: whatsnew/3 3 performance-and-resource-usage1661232
Ref: 108b1661232
Ref: Performance and resource usage-Footnote-11662465
Node: PEP 397 Python Launcher for Windows1662507
Ref: whatsnew/3 3 pep-3971662713
Ref: 108c1662713
Ref: whatsnew/3 3 pep-397-python-launcher-for-windows1662713
Ref: 108d1662713
Ref: PEP 397 Python Launcher for Windows-Footnote-11664258
Ref: PEP 397 Python Launcher for Windows-Footnote-21664322
Node: PEP 3151 Reworking the OS and IO exception hierarchy1664364
Ref: whatsnew/3 3 pep-31511664579
Ref: 10791664579
Ref: whatsnew/3 3 pep-3151-reworking-the-os-and-io-exception-hierarchy1664579
Ref: 108f1664579
Ref: PEP 3151 Reworking the OS and IO exception hierarchy-Footnote-11667160
Node: PEP 380 Syntax for Delegating to a Subgenerator1667202
Ref: whatsnew/3 3 pep-3801667419
Ref: 10771667419
Ref: whatsnew/3 3 pep-380-syntax-for-delegating-to-a-subgenerator1667419
Ref: 109e1667419
Ref: PEP 380 Syntax for Delegating to a Subgenerator-Footnote-11669865
Node: PEP 409 Suppressing exception context1669907
Ref: whatsnew/3 3 pep-409-suppressing-exception-context1670105
Ref: 10a01670105
Ref: PEP 409 Suppressing exception context-Footnote-11672195
Node: PEP 414 Explicit Unicode literals1672237
Ref: whatsnew/3 3 pep-414-explicit-unicode-literals1672437
Ref: 10a11672437
Ref: PEP 414 Explicit Unicode literals-Footnote-11673152
Node: PEP 3155 Qualified name for classes and functions1673194
Ref: whatsnew/3 3 pep-3155-qualified-name-for-classes-and-functions1673387
Ref: 10a21673387
Ref: PEP 3155 Qualified name for classes and functions-Footnote-11675004
Node: PEP 412 Key-Sharing Dictionary1675046
Ref: whatsnew/3 3 pep-4121675239
Ref: 107c1675239
Ref: whatsnew/3 3 pep-412-key-sharing-dictionary1675239
Ref: 10a51675239
Ref: PEP 412 Key-Sharing Dictionary-Footnote-11675760
Node: PEP 362 Function Signature Object1675802
Ref: whatsnew/3 3 pep-362-function-signature-object1675979
Ref: 10a61675979
Ref: PEP 362 Function Signature Object-Footnote-11676876
Node: PEP 421 Adding sys implementation1676918
Ref: whatsnew/3 3 pep-421-adding-sys-implementation1677112
Ref: 10a81677112
Ref: PEP 421 Adding sys implementation-Footnote-11678328
Node: SimpleNamespace1678370
Ref: whatsnew/3 3 simplenamespace1678455
Ref: 10a91678455
Ref: SimpleNamespace-Footnote-11679075
Node: Using importlib as the Implementation of Import1679117
Ref: whatsnew/3 3 importlib1679304
Ref: 107a1679304
Ref: whatsnew/3 3 using-importlib-as-the-implementation-of-import1679304
Ref: 10aa1679304
Ref: Using importlib as the Implementation of Import-Footnote-11680584
Ref: Using importlib as the Implementation of Import-Footnote-21680648
Ref: Using importlib as the Implementation of Import-Footnote-31680713
Ref: Using importlib as the Implementation of Import-Footnote-41680778
Ref: Using importlib as the Implementation of Import-Footnote-51680843
Node: New APIs1680885
Ref: whatsnew/3 3 new-apis1681001
Ref: 10ad1681001
Node: Visible Changes1682846
Ref: whatsnew/3 3 visible-changes1682962
Ref: 10b41682962
Ref: Visible Changes-Footnote-11684810
Ref: Visible Changes-Footnote-21684852
Node: Other Language Changes<11>1684894
Ref: whatsnew/3 3 other-language-changes1685075
Ref: 10b51685075
Ref: Other Language Changes<11>-Footnote-11687017
Ref: Other Language Changes<11>-Footnote-21687082
Ref: Other Language Changes<11>-Footnote-31687147
Ref: Other Language Changes<11>-Footnote-41687212
Ref: Other Language Changes<11>-Footnote-51687277
Ref: Other Language Changes<11>-Footnote-61687342
Ref: Other Language Changes<11>-Footnote-71687407
Ref: Other Language Changes<11>-Footnote-81687472
Node: A Finer-Grained Import Lock1687537
Ref: whatsnew/3 3 a-finer-grained-import-lock1687698
Ref: 10b81687698
Ref: A Finer-Grained Import Lock-Footnote-11688443
Node: Builtin functions and types1688507
Ref: whatsnew/3 3 builtin-functions-and-types1688657
Ref: 10b91688657
Ref: Builtin functions and types-Footnote-11689894
Node: New Modules<11>1689958
Ref: whatsnew/3 3 new-modules1690101
Ref: 10bc1690101
Node: faulthandler<4>1690229
Ref: whatsnew/3 3 faulthandler1690317
Ref: 10bd1690317
Node: ipaddress<6>1691276
Ref: whatsnew/3 3 ipaddress1691380
Ref: 10c41691380
Ref: ipaddress<6>-Footnote-11691726
Node: lzma<2>1691768
Ref: whatsnew/3 3 lzma1691848
Ref: 10c51691848
Ref: lzma<2>-Footnote-11692162
Node: Improved Modules<11>1692226
Ref: whatsnew/3 3 improved-modules1692359
Ref: 10c61692359
Node: abc<2>1693694
Ref: whatsnew/3 3 abc1693774
Ref: 10c71693774
Ref: abc<2>-Footnote-11694760
Ref: abc<2>-Footnote-21694825
Node: array<5>1694890
Ref: whatsnew/3 3 array1694988
Ref: 10cd1694988
Ref: array<5>-Footnote-11695222
Node: base64<4>1695289
Ref: whatsnew/3 3 base641695392
Ref: 10ce1695392
Ref: base64<4>-Footnote-11695692
Node: binascii<3>1695757
Ref: whatsnew/3 3 binascii1695858
Ref: 10cf1695858
Ref: binascii<3>-Footnote-11696114
Node: bz2<2>1696179
Ref: whatsnew/3 3 bz21696280
Ref: 10d01696280
Ref: bz2<2>-Footnote-11697249
Ref: bz2<2>-Footnote-21697313
Node: codecs<2>1697377
Ref: whatsnew/3 3 codecs1697481
Ref: 10d31697481
Ref: codecs<2>-Footnote-11698798
Ref: codecs<2>-Footnote-21698863
Ref: codecs<2>-Footnote-31698928
Node: collections<7>1698993
Ref: whatsnew/3 3 collections1699104
Ref: 10d41699104
Ref: collections<7>-Footnote-11699872
Ref: collections<7>-Footnote-21699937
Ref: collections<7>-Footnote-31700002
Ref: collections<7>-Footnote-41700067
Node: contextlib<7>1700132
Ref: whatsnew/3 3 contextlib1700242
Ref: 10d61700242
Ref: contextlib<7>-Footnote-11700837
Node: crypt<2>1700902
Ref: whatsnew/3 3 crypt1701007
Ref: 10d71701007
Ref: crypt<2>-Footnote-11701211
Node: curses<5>1701276
Ref: whatsnew/3 3 curses1701379
Ref: 10d81701379
Ref: curses<5>-Footnote-11702191
Node: datetime<6>1702255
Ref: whatsnew/3 3 datetime1702360
Ref: 10dd1702360
Ref: datetime<6>-Footnote-11703021
Node: decimal<3>1703086
Ref: whatsnew/3 3 decimal1703190
Ref: 10df1703190
Ref: whatsnew/3 3 new-decimal1703190
Ref: 107d1703190
Ref: decimal<3>-Footnote-11704896
Node: Features<2>1704960
Ref: whatsnew/3 3 id11705041
Ref: 10e01705041
Node: API changes<2>1705417
Ref: whatsnew/3 3 id21705498
Ref: 10e31705498
Node: email<5>1708347
Ref: whatsnew/3 3 email1708449
Ref: 10f51708449
Ref: whatsnew/3 3 new-email1708449
Ref: 107e1708449
Node: Policy Framework1708580
Ref: whatsnew/3 3 policy-framework1708688
Ref: 10f61708688
Node: Provisional Policy with New Header API1711606
Ref: whatsnew/3 3 provisional-policy-with-new-header-api1711740
Ref: 10fa1711740
Node: Other API Changes1716322
Ref: whatsnew/3 3 other-api-changes1716431
Ref: 10fe1716431
Node: ftplib<3>1717252
Ref: whatsnew/3 3 ftplib1717356
Ref: 11041717356
Ref: ftplib<3>-Footnote-11718269
Ref: ftplib<3>-Footnote-21718333
Ref: ftplib<3>-Footnote-31718398
Node: functools<6>1718463
Ref: whatsnew/3 3 functools1718564
Ref: 11091718564
Ref: functools<6>-Footnote-11718912
Node: gc<6>1718977
Ref: whatsnew/3 3 gc1719076
Ref: 110a1719076
Node: hmac<4>1719251
Ref: whatsnew/3 3 hmac1719345
Ref: 110c1719345
Ref: hmac<4>-Footnote-11719612
Node: http<4>1719677
Ref: whatsnew/3 3 http1719773
Ref: 110e1719773
Ref: http<4>-Footnote-11720459
Ref: http<4>-Footnote-21720523
Ref: http<4>-Footnote-31720588
Node: html<2>1720653
Ref: whatsnew/3 3 html1720752
Ref: 11151720752
Ref: html<2>-Footnote-11721753
Ref: html<2>-Footnote-21721818
Ref: html<2>-Footnote-31721883
Ref: html<2>-Footnote-41721948
Ref: html<2>-Footnote-51722013
Ref: html<2>-Footnote-61722078
Ref: html<2>-Footnote-71722145
Ref: html<2>-Footnote-81722211
Ref: html<2>-Footnote-91722276
Ref: html<2>-Footnote-101722341
Ref: html<2>-Footnote-111722409
Ref: html<2>-Footnote-121722476
Ref: html<2>-Footnote-131722542
Ref: html<2>-Footnote-141722608
Ref: html<2>-Footnote-151722673
Ref: html<2>-Footnote-161722739
Node: imaplib<3>1722805
Ref: whatsnew/3 3 imaplib1722907
Ref: 11171722907
Ref: imaplib<3>-Footnote-11723149
Node: inspect<9>1723213
Ref: whatsnew/3 3 inspect1723313
Ref: 11181723313
Ref: inspect<9>-Footnote-11724027
Ref: inspect<9>-Footnote-21724092
Node: io<6>1724157
Ref: whatsnew/3 3 io1724259
Ref: 111b1724259
Ref: io<6>-Footnote-11724903
Node: itertools<6>1724968
Ref: whatsnew/3 3 itertools1725070
Ref: 111c1725070
Node: logging<7>1725228
Ref: whatsnew/3 3 logging1725332
Ref: 111d1725332
Node: math<9>1725785
Ref: whatsnew/3 3 math1725884
Ref: 111e1725884
Ref: math<9>-Footnote-11726110
Node: mmap<4>1726175
Ref: whatsnew/3 3 mmap1726282
Ref: 11201726282
Ref: mmap<4>-Footnote-11726620
Node: multiprocessing<8>1726685
Ref: whatsnew/3 3 multiprocessing1726795
Ref: 11221726795
Ref: multiprocessing<8>-Footnote-11727972
Ref: multiprocessing<8>-Footnote-21728037
Ref: multiprocessing<8>-Footnote-31728101
Ref: multiprocessing<8>-Footnote-41728165
Node: nntplib<2>1728230
Ref: whatsnew/3 3 nntplib1728339
Ref: 112b1728339
Ref: nntplib<2>-Footnote-11728899
Node: os<12>1728963
Ref: whatsnew/3 3 os1729060
Ref: 112c1729060
Ref: os<12>-Footnote-11736510
Ref: os<12>-Footnote-21736575
Ref: os<12>-Footnote-31736639
Ref: os<12>-Footnote-41736704
Ref: os<12>-Footnote-51736769
Ref: os<12>-Footnote-61736834
Ref: os<12>-Footnote-71736898
Ref: os<12>-Footnote-81736963
Ref: os<12>-Footnote-91737028
Ref: os<12>-Footnote-101737093
Ref: os<12>-Footnote-111737158
Node: pdb<7>1737224
Ref: whatsnew/3 3 pdb1737320
Ref: 11641737320
Ref: pdb<7>-Footnote-11737603
Node: pickle<5>1737668
Ref: whatsnew/3 3 pickle1737766
Ref: 11651737766
Ref: pickle<5>-Footnote-11738037
Node: pydoc<5>1738102
Ref: whatsnew/3 3 pydoc1738199
Ref: 11671738199
Node: re<9>1738398
Ref: whatsnew/3 3 re1738491
Ref: 11681738491
Ref: re<9>-Footnote-11738687
Node: sched1738751
Ref: whatsnew/3 3 sched1738845
Ref: 11691738845
Ref: sched-Footnote-11739992
Ref: sched-Footnote-21740057
Ref: sched-Footnote-31740121
Ref: sched-Footnote-41740186
Ref: sched-Footnote-51740251
Node: select<2>1740316
Ref: whatsnew/3 3 select1740413
Ref: 116e1740413
Ref: select<2>-Footnote-11740678
Node: shlex<3>1740742
Ref: whatsnew/3 3 shlex1740843
Ref: 116f1740843
Node: shutil<7>1741150
Ref: whatsnew/3 3 shutil1741251
Ref: 11701741251
Ref: shutil<7>-Footnote-11743120
Ref: shutil<7>-Footnote-21743185
Ref: shutil<7>-Footnote-31743250
Ref: shutil<7>-Footnote-41743315
Ref: shutil<7>-Footnote-51743380
Ref: shutil<7>-Footnote-61743445
Ref: shutil<7>-Footnote-71743510
Ref: shutil<7>-Footnote-81743574
Node: signal<4>1743638
Ref: whatsnew/3 3 signal1743739
Ref: 11731743739
Ref: signal<4>-Footnote-11744812
Node: smtpd<4>1744876
Ref: whatsnew/3 3 smtpd1744978
Ref: 117a1744978
Ref: smtpd<4>-Footnote-11745461
Ref: smtpd<4>-Footnote-21745520
Ref: smtpd<4>-Footnote-31745579
Node: smtplib<4>1745643
Ref: whatsnew/3 3 smtplib1745746
Ref: 117b1745746
Ref: smtplib<4>-Footnote-11746500
Ref: smtplib<4>-Footnote-21746565
Ref: smtplib<4>-Footnote-31746630
Node: socket<10>1746694
Ref: whatsnew/3 3 socket1746804
Ref: 117d1746804
Ref: socket<10>-Footnote-11748046
Ref: socket<10>-Footnote-21748110
Ref: socket<10>-Footnote-31748175
Ref: socket<10>-Footnote-41748264
Ref: socket<10>-Footnote-51748329
Node: socketserver<3>1748394
Ref: whatsnew/3 3 socketserver1748505
Ref: 11801748505
Ref: socketserver<3>-Footnote-11748883
Node: sqlite3<10>1748948
Ref: whatsnew/3 3 sqlite31749056
Ref: 11841749056
Ref: sqlite3<10>-Footnote-11749333
Node: ssl<11>1749398
Ref: whatsnew/3 3 ssl1749498
Ref: 11851749498
Ref: ssl<11>-Footnote-11751719
Ref: ssl<11>-Footnote-21751784
Ref: ssl<11>-Footnote-31751849
Ref: ssl<11>-Footnote-41751914
Ref: ssl<11>-Footnote-51751979
Ref: ssl<11>-Footnote-61752044
Ref: ssl<11>-Footnote-71752109
Ref: ssl<11>-Footnote-81752174
Ref: ssl<11>-Footnote-91752239
Ref: ssl<11>-Footnote-101752304
Ref: ssl<11>-Footnote-111752370
Node: stat<2>1752436
Ref: whatsnew/3 3 stat1752534
Ref: 118e1752534
Ref: stat<2>-Footnote-11752832
Node: struct<3>1752897
Ref: whatsnew/3 3 struct1753001
Ref: 11901753001
Ref: struct<3>-Footnote-11753250
Node: subprocess<6>1753314
Ref: whatsnew/3 3 subprocess1753418
Ref: 11911753418
Ref: subprocess<6>-Footnote-11753756
Ref: subprocess<6>-Footnote-21753820
Node: sys<13>1753884
Ref: whatsnew/3 3 sys1753989
Ref: 11931753989
Ref: sys<13>-Footnote-11754210
Node: tarfile<9>1754275
Ref: whatsnew/3 3 tarfile1754378
Ref: 11951754378
Ref: tarfile<9>-Footnote-11754587
Node: tempfile<4>1754651
Ref: whatsnew/3 3 tempfile1754758
Ref: 11961754758
Ref: tempfile<4>-Footnote-11754985
Node: textwrap<2>1755049
Ref: whatsnew/3 3 textwrap1755158
Ref: 11971755158
Ref: textwrap<2>-Footnote-11755404
Node: threading<8>1755469
Ref: whatsnew/3 3 threading1755574
Ref: 11981755574
Ref: threading<8>-Footnote-11756513
Ref: threading<8>-Footnote-21756578
Node: time<8>1756642
Ref: whatsnew/3 3 time1756744
Ref: 119f1756744
Ref: time<8>-Footnote-11757716
Ref: time<8>-Footnote-21757758
Node: types<7>1757823
Ref: whatsnew/3 3 types1757925
Ref: 11a41757925
Ref: types<7>-Footnote-11758265
Ref: types<7>-Footnote-21758330
Ref: types<7>-Footnote-31758372
Node: unittest<10>1758437
Ref: whatsnew/3 3 unittest1758541
Ref: 11a71758541
Ref: unittest<10>-Footnote-11758960
Node: urllib<4>1759025
Ref: whatsnew/3 3 urllib1759134
Ref: 11ac1759134
Ref: urllib<4>-Footnote-11759490
Node: webbrowser<3>1759557
Ref: whatsnew/3 3 webbrowser1759678
Ref: 11ae1759678
Ref: webbrowser<3>-Footnote-11760222
Ref: webbrowser<3>-Footnote-21760287
Node: xml etree ElementTree<2>1760352
Ref: whatsnew/3 3 xml-etree-elementtree1760471
Ref: 11af1760471
Node: zlib<2>1760992
Ref: whatsnew/3 3 zlib1761089
Ref: 11b01761089
Ref: zlib<2>-Footnote-11761565
Ref: zlib<2>-Footnote-21761630
Node: Optimizations<10>1761695
Ref: whatsnew/3 3 optimizations1761839
Ref: 11b31761839
Ref: Optimizations<10>-Footnote-11762652
Ref: Optimizations<10>-Footnote-21762694
Ref: Optimizations<10>-Footnote-31762759
Ref: Optimizations<10>-Footnote-41762824
Node: Build and C API Changes<4>1762889
Ref: whatsnew/3 3 build-and-c-api-changes1763027
Ref: 10861763027
Ref: Build and C API Changes<4>-Footnote-11764918
Ref: Build and C API Changes<4>-Footnote-21764960
Ref: Build and C API Changes<4>-Footnote-31765002
Node: Deprecated<12>1765067
Ref: whatsnew/3 3 deprecated1765209
Ref: 11c91765209
Node: Unsupported Operating Systems<2>1765548
Ref: whatsnew/3 3 unsupported-operating-systems1765690
Ref: 11ca1765690
Node: Deprecated Python modules functions and methods<4>1766046
Ref: whatsnew/3 3 deprecated-python-modules-functions-and-methods1766243
Ref: 11cb1766243
Ref: Deprecated Python modules functions and methods<4>-Footnote-11768595
Ref: Deprecated Python modules functions and methods<4>-Footnote-21768659
Ref: Deprecated Python modules functions and methods<4>-Footnote-31768701
Ref: Deprecated Python modules functions and methods<4>-Footnote-41768766
Ref: Deprecated Python modules functions and methods<4>-Footnote-51768831
Node: Deprecated functions and types of the C API<3>1768896
Ref: whatsnew/3 3 deprecated-functions-and-types-of-the-c-api1769080
Ref: 11cf1769080
Ref: Deprecated functions and types of the C API<3>-Footnote-11772106
Node: Deprecated features1772148
Ref: whatsnew/3 3 deprecated-features1772273
Ref: 11d91772273
Node: Porting to Python 3 31772498
Ref: whatsnew/3 3 porting-to-python-3-31772605
Ref: 11da1772605
Node: Porting Python code1772884
Ref: whatsnew/3 3 porting-python-code1772984
Ref: 10ac1772984
Ref: whatsnew/3 3 portingpythoncode1772984
Ref: 11db1772984
Ref: Porting Python code-Footnote-11780017
Ref: Porting Python code-Footnote-21780082
Ref: Porting Python code-Footnote-31780147
Ref: Porting Python code-Footnote-41780212
Ref: Porting Python code-Footnote-51780254
Ref: Porting Python code-Footnote-61780296
Ref: Porting Python code-Footnote-71780360
Ref: Porting Python code-Footnote-81780427
Ref: Porting Python code-Footnote-91780492
Ref: Porting Python code-Footnote-101780556
Node: Porting C code1780622
Ref: whatsnew/3 3 porting-c-code1780752
Ref: 10871780752
Ref: Porting C code-Footnote-11782253
Node: Building C extensions1782295
Ref: whatsnew/3 3 building-c-extensions1782433
Ref: 11ea1782433
Ref: Building C extensions-Footnote-11783033
Node: Command Line Switch Changes1783098
Ref: whatsnew/3 3 command-line-switch-changes1783213
Ref: 11eb1783213
Ref: Command Line Switch Changes-Footnote-11783781
Ref: Command Line Switch Changes-Footnote-21783846
Node: What’s New In Python 3 21783911
Ref: whatsnew/3 2 doc1784066
Ref: 11ed1784066
Ref: whatsnew/3 2 translation-repo1784066
Ref: 11ee1784066
Ref: whatsnew/3 2 what-s-new-in-python-3-21784066
Ref: 11ef1784066
Ref: What’s New In Python 3 2-Footnote-11785465
Ref: What’s New In Python 3 2-Footnote-21785564
Node: PEP 384 Defining a Stable ABI1785606
Ref: whatsnew/3 2 pep-384-defining-a-stable-abi1785751
Ref: 11f01785751
Ref: PEP 384 Defining a Stable ABI-Footnote-11786844
Node: PEP 389 Argparse Command Line Parsing Module1786886
Ref: whatsnew/3 2 pep-389-argparse-command-line-parsing-module1787090
Ref: 11f11787090
Ref: PEP 389 Argparse Command Line Parsing Module-Footnote-11791231
Node: PEP 391 Dictionary Based Configuration for Logging1791273
Ref: whatsnew/3 2 pep-391-dictionary-based-configuration-for-logging1791486
Ref: 11f31791486
Ref: PEP 391 Dictionary Based Configuration for Logging-Footnote-11793785
Node: PEP 3148 The concurrent futures module1793827
Ref: whatsnew/3 2 pep-3148-the-concurrent-futures-module1794031
Ref: 11f51794031
Ref: PEP 3148 The concurrent futures module-Footnote-11796735
Node: PEP 3147 PYC Repository Directories1796777
Ref: whatsnew/3 2 pep-3147-pyc-repository-directories1796967
Ref: 11f91796967
Ref: PEP 3147 PYC Repository Directories-Footnote-11800038
Node: PEP 3149 ABI Version Tagged so Files1800080
Ref: whatsnew/3 2 pep-3149-abi-version-tagged-so-files1800283
Ref: 11fb1800283
Ref: PEP 3149 ABI Version Tagged so Files-Footnote-11801543
Node: PEP 3333 Python Web Server Gateway Interface v1 0 11801585
Ref: whatsnew/3 2 pep-3333-python-web-server-gateway-interface-v1-0-11801779
Ref: 11fc1801779
Ref: PEP 3333 Python Web Server Gateway Interface v1 0 1-Footnote-11804145
Ref: PEP 3333 Python Web Server Gateway Interface v1 0 1-Footnote-21804204
Ref: PEP 3333 Python Web Server Gateway Interface v1 0 1-Footnote-31804263
Node: Other Language Changes<12>1804305
Ref: whatsnew/3 2 other-language-changes1804498
Ref: 11ff1804498
Ref: Other Language Changes<12>-Footnote-11814014
Ref: Other Language Changes<12>-Footnote-21814078
Ref: Other Language Changes<12>-Footnote-31814142
Ref: Other Language Changes<12>-Footnote-41814209
Ref: Other Language Changes<12>-Footnote-51814273
Ref: Other Language Changes<12>-Footnote-61814337
Ref: Other Language Changes<12>-Footnote-71814401
Ref: Other Language Changes<12>-Footnote-81814465
Ref: Other Language Changes<12>-Footnote-91814529
Ref: Other Language Changes<12>-Footnote-101814593
Ref: Other Language Changes<12>-Footnote-111814659
Ref: Other Language Changes<12>-Footnote-121814726
Ref: Other Language Changes<12>-Footnote-131814791
Ref: Other Language Changes<12>-Footnote-141814856
Ref: Other Language Changes<12>-Footnote-151814922
Ref: Other Language Changes<12>-Footnote-161814988
Node: New Improved and Deprecated Modules1815053
Ref: whatsnew/3 2 new-improved-and-deprecated-modules1815210
Ref: 120c1815210
Node: email<6>1817241
Ref: whatsnew/3 2 email1817341
Ref: 120d1817341
Ref: email<6>-Footnote-11819324
Ref: email<6>-Footnote-21819383
Ref: email<6>-Footnote-31819447
Node: elementtree1819512
Ref: whatsnew/3 2 elementtree1819633
Ref: 12151819633
Ref: elementtree-Footnote-11821120
Ref: elementtree-Footnote-21821220
Node: functools<7>1821284
Ref: whatsnew/3 2 functools1821409
Ref: 121c1821409
Ref: functools<7>-Footnote-11824881
Ref: functools<7>-Footnote-21824964
Ref: functools<7>-Footnote-31825043
Ref: functools<7>-Footnote-41825108
Ref: functools<7>-Footnote-51825173
Ref: functools<7>-Footnote-61825237
Ref: functools<7>-Footnote-71825301
Ref: functools<7>-Footnote-81825365
Node: itertools<7>1825417
Ref: whatsnew/3 2 itertools1825545
Ref: 12201825545
Node: collections<8>1826238
Ref: whatsnew/3 2 collections1826366
Ref: 12221826366
Ref: collections<8>-Footnote-11828615
Ref: collections<8>-Footnote-21828675
Node: threading<9>1828722
Ref: whatsnew/3 2 threading1828855
Ref: 12271828855
Ref: threading<9>-Footnote-11831621
Ref: threading<9>-Footnote-21831682
Ref: threading<9>-Footnote-31831781
Ref: threading<9>-Footnote-41831853
Node: datetime and time1831917
Ref: whatsnew/3 2 datetime-and-time1832044
Ref: 122b1832044
Ref: datetime and time-Footnote-11834811
Ref: datetime and time-Footnote-21834878
Ref: datetime and time-Footnote-31834942
Ref: datetime and time-Footnote-41835006
Ref: datetime and time-Footnote-51835070
Ref: datetime and time-Footnote-61835137
Ref: datetime and time-Footnote-71835201
Node: math<10>1835266
Ref: whatsnew/3 2 math1835387
Ref: 122f1835387
Ref: math<10>-Footnote-11837270
Node: abc<3>1837323
Ref: whatsnew/3 2 abc1837432
Ref: 12341837432
Ref: abc<3>-Footnote-11838059
Node: io<7>1838123
Ref: whatsnew/3 2 io1838231
Ref: 12351838231
Ref: io<7>-Footnote-11839399
Node: reprlib1839463
Ref: whatsnew/3 2 reprlib1839575
Ref: 12371839575
Ref: reprlib-Footnote-11840560
Ref: reprlib-Footnote-21840624
Node: logging<8>1840688
Ref: whatsnew/3 2 logging1840801
Ref: 12391840801
Node: csv<4>1842666
Ref: whatsnew/3 2 csv1842785
Ref: 12411842785
Ref: csv<4>-Footnote-11843651
Ref: csv<4>-Footnote-21843715
Node: contextlib<8>1843782
Ref: whatsnew/3 2 contextlib1843912
Ref: 12451843912
Ref: contextlib<8>-Footnote-11846130
Node: decimal and fractions1846194
Ref: whatsnew/3 2 decimal-and-fractions1846321
Ref: 12481846321
Ref: decimal and fractions-Footnote-11848755
Ref: decimal and fractions-Footnote-21848819
Ref: decimal and fractions-Footnote-31848883
Ref: decimal and fractions-Footnote-41848947
Ref: decimal and fractions-Footnote-51849011
Ref: decimal and fractions-Footnote-61849075
Node: ftp1849139
Ref: whatsnew/3 2 ftp1849258
Ref: 124c1849258
Ref: ftp-Footnote-11850603
Ref: ftp-Footnote-21850667
Ref: ftp-Footnote-31850731
Ref: ftp-Footnote-41850795
Node: popen1850859
Ref: whatsnew/3 2 popen1850966
Ref: 124d1850966
Ref: popen-Footnote-11851273
Ref: popen-Footnote-21851337
Node: select<3>1851402
Ref: whatsnew/3 2 select1851522
Ref: 124e1851522
Ref: select<3>-Footnote-11851956
Node: gzip and zipfile1852020
Ref: whatsnew/3 2 gzip-and-zipfile1852146
Ref: 12501852146
Ref: gzip and zipfile-Footnote-11853713
Ref: gzip and zipfile-Footnote-21853777
Ref: gzip and zipfile-Footnote-31853841
Ref: gzip and zipfile-Footnote-41853908
Ref: gzip and zipfile-Footnote-51853972
Ref: gzip and zipfile-Footnote-61854036
Node: tarfile<10>1854100
Ref: whatsnew/3 2 tarfile1854227
Ref: 12541854227
Ref: tarfile<10>-Footnote-11855796
Node: hashlib<7>1855860
Ref: whatsnew/3 2 hashlib1855977
Ref: 12571855977
Ref: hashlib<7>-Footnote-11856734
Node: ast<5>1856798
Ref: whatsnew/3 2 ast1856910
Ref: 12581856910
Node: os<13>1857849
Ref: whatsnew/3 2 os1857960
Ref: 12591857960
Node: shutil<8>1858735
Ref: whatsnew/3 2 shutil1858851
Ref: 125d1858851
Node: sqlite3<11>1861021
Ref: whatsnew/3 2 sqlite31861138
Ref: 125f1861138
Ref: sqlite3<11>-Footnote-11861789
Node: html<3>1861853
Ref: whatsnew/3 2 html1861971
Ref: 12601861971
Node: socket<11>1862260
Ref: whatsnew/3 2 socket1862374
Ref: 12611862374
Ref: socket<11>-Footnote-11863020
Ref: socket<11>-Footnote-21863084
Node: ssl<12>1863148
Ref: whatsnew/3 2 ssl1863259
Ref: 12631863259
Ref: ssl<12>-Footnote-11865361
Ref: ssl<12>-Footnote-21865420
Ref: ssl<12>-Footnote-31865492
Ref: ssl<12>-Footnote-41865556
Ref: ssl<12>-Footnote-51865620
Ref: ssl<12>-Footnote-61865684
Ref: ssl<12>-Footnote-71865748
Ref: ssl<12>-Footnote-81865812
Ref: ssl<12>-Footnote-91865876
Node: nntp1865940
Ref: whatsnew/3 2 nntp1866053
Ref: 12671866053
Ref: nntp-Footnote-11866608
Ref: nntp-Footnote-21866672
Node: certificates1866736
Ref: whatsnew/3 2 certificates1866852
Ref: 12681866852
Ref: certificates-Footnote-11867250
Node: imaplib<4>1867314
Ref: whatsnew/3 2 imaplib1867440
Ref: 126a1867440
Ref: imaplib<4>-Footnote-11867714
Node: http client<4>1867778
Ref: whatsnew/3 2 http-client1867904
Ref: 126c1867904
Ref: http client<4>-Footnote-11869331
Node: unittest<11>1869396
Ref: whatsnew/3 2 unittest1869521
Ref: 126f1869521
Ref: unittest<11>-Footnote-11874205
Ref: unittest<11>-Footnote-21874270
Ref: unittest<11>-Footnote-31874334
Node: random<5>1874398
Ref: whatsnew/3 2 random1874518
Ref: 12741874518
Ref: random<5>-Footnote-11875184
Node: poplib<4>1875248
Ref: whatsnew/3 2 poplib1875367
Ref: 12771875367
Ref: poplib<4>-Footnote-11875721
Node: asyncore<2>1875785
Ref: whatsnew/3 2 asyncore1875906
Ref: 12781875906
Ref: asyncore<2>-Footnote-11876361
Node: tempfile<5>1876425
Ref: whatsnew/3 2 tempfile1876548
Ref: 12791876548
Ref: tempfile<5>-Footnote-11876957
Node: inspect<10>1877021
Ref: whatsnew/3 2 inspect1877141
Ref: 127b1877141
Ref: inspect<10>-Footnote-11878516
Node: pydoc<6>1878581
Ref: whatsnew/3 2 pydoc1878696
Ref: 127d1878696
Ref: pydoc<6>-Footnote-11879015
Node: dis<5>1879079
Ref: whatsnew/3 2 dis1879189
Ref: 127e1879189
Ref: dis<5>-Footnote-11881340
Node: dbm<7>1881404
Ref: whatsnew/3 2 dbm1881515
Ref: 12801881515
Ref: dbm<7>-Footnote-11881704
Node: ctypes<3>1881768
Ref: whatsnew/3 2 ctypes1881880
Ref: 12811881880
Node: site<4>1881999
Ref: whatsnew/3 2 site1882117
Ref: 12831882117
Ref: site<4>-Footnote-11883351
Node: sysconfig<3>1883415
Ref: whatsnew/3 2 sysconfig1883530
Ref: 12871883530
Node: pdb<8>1885761
Ref: whatsnew/3 2 pdb1885884
Ref: 128b1885884
Node: configparser<5>1886795
Ref: whatsnew/3 2 configparser1886921
Ref: 128c1886921
Node: urllib parse<6>1889787
Ref: whatsnew/3 2 urllib-parse1889914
Ref: 128d1889914
Ref: urllib parse<6>-Footnote-11891927
Ref: urllib parse<6>-Footnote-21891970
Ref: urllib parse<6>-Footnote-31892029
Ref: urllib parse<6>-Footnote-41892093
Ref: urllib parse<6>-Footnote-51892157
Node: mailbox1892221
Ref: whatsnew/3 2 mailbox1892343
Ref: 12911892343
Ref: mailbox-Footnote-11893923
Node: turtledemo1893987
Ref: whatsnew/3 2 turtledemo1894085
Ref: 12981894085
Ref: turtledemo-Footnote-11894522
Node: Multi-threading1894587
Ref: whatsnew/3 2 multi-threading1894735
Ref: 12991894735
Ref: Multi-threading-Footnote-11896381
Ref: Multi-threading-Footnote-21896460
Ref: Multi-threading-Footnote-31896524
Ref: Multi-threading-Footnote-41896590
Node: Optimizations<11>1896654
Ref: whatsnew/3 2 optimizations1896774
Ref: 129b1896774
Ref: Optimizations<11>-Footnote-11900274
Ref: Optimizations<11>-Footnote-21900338
Ref: Optimizations<11>-Footnote-31900402
Ref: Optimizations<11>-Footnote-41900466
Ref: Optimizations<11>-Footnote-51900512
Ref: Optimizations<11>-Footnote-61900576
Ref: Optimizations<11>-Footnote-71900640
Ref: Optimizations<11>-Footnote-81900705
Ref: Optimizations<11>-Footnote-91900769
Ref: Optimizations<11>-Footnote-101900833
Ref: Optimizations<11>-Footnote-111900898
Ref: Optimizations<11>-Footnote-121900963
Ref: Optimizations<11>-Footnote-131901028
Ref: Optimizations<11>-Footnote-141901096
Ref: Optimizations<11>-Footnote-151901161
Ref: Optimizations<11>-Footnote-161901227
Node: Unicode1901292
Ref: whatsnew/3 2 unicode1901403
Ref: 12a01901403
Ref: Unicode-Footnote-11901955
Ref: Unicode-Footnote-21902006
Ref: Unicode-Footnote-31902050
Node: Codecs1902122
Ref: whatsnew/3 2 codecs1902229
Ref: 12a11902229
Ref: Codecs-Footnote-11903159
Node: Documentation1903226
Ref: whatsnew/3 2 documentation1903330
Ref: 12a21903330
Ref: Documentation-Footnote-11904979
Ref: Documentation-Footnote-21905048
Ref: Documentation-Footnote-31905124
Ref: Documentation-Footnote-41905188
Node: IDLE1905252
Ref: whatsnew/3 2 idle1905365
Ref: 12a61905365
Ref: IDLE-Footnote-11905751
Ref: IDLE-Footnote-21905815
Node: Code Repository1905879
Ref: whatsnew/3 2 code-repository1906005
Ref: 12a71906005
Ref: Code Repository-Footnote-11906614
Ref: Code Repository-Footnote-21906653
Ref: Code Repository-Footnote-31906695
Ref: Code Repository-Footnote-41906749
Node: Build and C API Changes<5>1906793
Ref: whatsnew/3 2 build-and-c-api-changes1906936
Ref: 12a81906936
Ref: Build and C API Changes<5>-Footnote-11911084
Ref: Build and C API Changes<5>-Footnote-21911149
Ref: Build and C API Changes<5>-Footnote-31911213
Ref: Build and C API Changes<5>-Footnote-41911277
Ref: Build and C API Changes<5>-Footnote-51911341
Ref: Build and C API Changes<5>-Footnote-61911405
Ref: Build and C API Changes<5>-Footnote-71911469
Ref: Build and C API Changes<5>-Footnote-81911533
Ref: Build and C API Changes<5>-Footnote-91911597
Ref: Build and C API Changes<5>-Footnote-101911661
Ref: Build and C API Changes<5>-Footnote-111911726
Ref: Build and C API Changes<5>-Footnote-121911791
Ref: Build and C API Changes<5>-Footnote-131911856
Ref: Build and C API Changes<5>-Footnote-141911921
Ref: Build and C API Changes<5>-Footnote-151912004
Node: Porting to Python 3 21912105
Ref: whatsnew/3 2 porting-to-python-3-21912224
Ref: 12b11912224
Ref: Porting to Python 3 2-Footnote-11919079
Ref: Porting to Python 3 2-Footnote-21919143
Ref: Porting to Python 3 2-Footnote-31919207
Ref: Porting to Python 3 2-Footnote-41919252
Ref: Porting to Python 3 2-Footnote-51919317
Ref: Porting to Python 3 2-Footnote-61919382
Ref: Porting to Python 3 2-Footnote-71919447
Node: What’s New In Python 3 11919511
Ref: whatsnew/3 1 doc1919666
Ref: 12c11919666
Ref: whatsnew/3 1 translation-repo1919666
Ref: 12c21919666
Ref: whatsnew/3 1 what-s-new-in-python-3-11919666
Ref: 12c31919666
Node: PEP 372 Ordered Dictionaries1920339
Ref: whatsnew/3 1 pep-372-ordered-dictionaries1920487
Ref: 12c41920487
Ref: PEP 372 Ordered Dictionaries-Footnote-11922995
Ref: PEP 372 Ordered Dictionaries-Footnote-21923023
Node: PEP 378 Format Specifier for Thousands Separator1923065
Ref: whatsnew/3 1 pep-378-format-specifier-for-thousands-separator1923248
Ref: 12c51923248
Ref: PEP 378 Format Specifier for Thousands Separator-Footnote-11924489
Node: Other Language Changes<13>1924531
Ref: whatsnew/3 1 other-language-changes1924724
Ref: 12c61924724
Ref: Other Language Changes<13>-Footnote-11929525
Ref: Other Language Changes<13>-Footnote-21929592
Ref: Other Language Changes<13>-Footnote-31929656
Ref: Other Language Changes<13>-Footnote-41929720
Ref: Other Language Changes<13>-Footnote-51929784
Ref: Other Language Changes<13>-Footnote-61929829
Ref: Other Language Changes<13>-Footnote-71929893
Node: New Improved and Deprecated Modules<2>1929957
Ref: whatsnew/3 1 new-improved-and-deprecated-modules1930119
Ref: 12c71930119
Ref: New Improved and Deprecated Modules<2>-Footnote-11938726
Ref: New Improved and Deprecated Modules<2>-Footnote-21938793
Ref: New Improved and Deprecated Modules<2>-Footnote-31938857
Ref: New Improved and Deprecated Modules<2>-Footnote-41938921
Ref: New Improved and Deprecated Modules<2>-Footnote-51938985
Ref: New Improved and Deprecated Modules<2>-Footnote-61939049
Ref: New Improved and Deprecated Modules<2>-Footnote-71939091
Ref: New Improved and Deprecated Modules<2>-Footnote-81939155
Ref: New Improved and Deprecated Modules<2>-Footnote-91939219
Ref: New Improved and Deprecated Modules<2>-Footnote-101939283
Ref: New Improved and Deprecated Modules<2>-Footnote-111939348
Ref: New Improved and Deprecated Modules<2>-Footnote-121939413
Ref: New Improved and Deprecated Modules<2>-Footnote-131939478
Node: Optimizations<12>1939543
Ref: whatsnew/3 1 optimizations1939686
Ref: 12d71939686
Ref: Optimizations<12>-Footnote-11941865
Ref: Optimizations<12>-Footnote-21941907
Ref: Optimizations<12>-Footnote-31941971
Ref: Optimizations<12>-Footnote-41942035
Ref: Optimizations<12>-Footnote-51942099
Ref: Optimizations<12>-Footnote-61942125
Ref: Optimizations<12>-Footnote-71942189
Node: IDLE<2>1942253
Ref: whatsnew/3 1 idle1942384
Ref: 12d81942384
Ref: IDLE<2>-Footnote-11942601
Node: Build and C API Changes<6>1942665
Ref: whatsnew/3 1 build-and-c-api-changes1942800
Ref: 12d91942800
Ref: Build and C API Changes<6>-Footnote-11945067
Ref: Build and C API Changes<6>-Footnote-21945131
Ref: Build and C API Changes<6>-Footnote-31945195
Ref: Build and C API Changes<6>-Footnote-41945259
Ref: Build and C API Changes<6>-Footnote-51945323
Node: Porting to Python 3 11945387
Ref: whatsnew/3 1 porting-to-python-3-11945506
Ref: 12dd1945506
Node: What’s New In Python 3 01946638
Ref: whatsnew/3 0 doc1946793
Ref: 12de1946793
Ref: whatsnew/3 0 translation-repo1946793
Ref: 12df1946793
Ref: whatsnew/3 0 what-s-new-in-python-3-01946793
Ref: 12e01946793
Node: Common Stumbling Blocks1948651
Ref: whatsnew/3 0 common-stumbling-blocks1948772
Ref: 12e11948772
Node: Print Is A Function1949142
Ref: whatsnew/3 0 print-is-a-function1949266
Ref: 12e21949266
Ref: Print Is A Function-Footnote-11950952
Node: Views And Iterators Instead Of Lists1950994
Ref: whatsnew/3 0 views-and-iterators-instead-of-lists1951147
Ref: 12e31951147
Node: Ordering Comparisons1952967
Ref: whatsnew/3 0 ordering-comparisons1953109
Ref: 12e61953109
Node: Integers1954561
Ref: whatsnew/3 0 integers1954707
Ref: 12e81954707
Ref: Integers-Footnote-11955926
Ref: Integers-Footnote-21955968
Node: Text Vs Data Instead Of Unicode Vs 8-bit1956010
Ref: whatsnew/3 0 text-vs-data-instead-of-unicode-vs-8-bit1956127
Ref: 12e91956127
Ref: Text Vs Data Instead Of Unicode Vs 8-bit-Footnote-11962638
Ref: Text Vs Data Instead Of Unicode Vs 8-bit-Footnote-21962680
Ref: Text Vs Data Instead Of Unicode Vs 8-bit-Footnote-31962722
Node: Overview Of Syntax Changes1962764
Ref: whatsnew/3 0 overview-of-syntax-changes1962931
Ref: 12ed1962931
Node: New Syntax1963143
Ref: whatsnew/3 0 new-syntax1963239
Ref: 12ee1963239
Ref: New Syntax-Footnote-11965789
Ref: New Syntax-Footnote-21965831
Ref: New Syntax-Footnote-31965873
Ref: New Syntax-Footnote-41965915
Ref: New Syntax-Footnote-51965957
Node: Changed Syntax1965999
Ref: whatsnew/3 0 changed-syntax1966118
Ref: 12f11966118
Ref: Changed Syntax-Footnote-11967797
Ref: Changed Syntax-Footnote-21967839
Ref: Changed Syntax-Footnote-31967881
Ref: Changed Syntax-Footnote-41967923
Node: Removed Syntax1967965
Ref: whatsnew/3 0 removed-syntax1968065
Ref: 12f21968065
Ref: Removed Syntax-Footnote-11969238
Ref: Removed Syntax-Footnote-21969280
Node: Changes Already Present In Python 2 61969322
Ref: whatsnew/3 0 changes-already-present-in-python-2-61969481
Ref: 12f41969481
Node: Library Changes1973352
Ref: whatsnew/3 0 library-changes1973529
Ref: 13071973529
Ref: Library Changes-Footnote-11979749
Ref: Library Changes-Footnote-21979791
Ref: Library Changes-Footnote-31979833
Ref: Library Changes-Footnote-41979875
Ref: Library Changes-Footnote-51979917
Ref: Library Changes-Footnote-61979959
Node: PEP 3101 A New Approach To String Formatting1980001
Ref: whatsnew/3 0 pep-3101-a-new-approach-to-string-formatting1980162
Ref: 130c1980162
Ref: PEP 3101 A New Approach To String Formatting-Footnote-11980554
Node: Changes To Exceptions1980596
Ref: whatsnew/3 0 changes-to-exceptions1980769
Ref: 130d1980769
Ref: Changes To Exceptions-Footnote-11984296
Ref: Changes To Exceptions-Footnote-21984338
Ref: Changes To Exceptions-Footnote-31984380
Ref: Changes To Exceptions-Footnote-41984422
Ref: Changes To Exceptions-Footnote-51984464
Node: Miscellaneous Other Changes1984506
Ref: whatsnew/3 0 miscellaneous-other-changes1984661
Ref: 13111984661
Node: Operators And Special Methods1984789
Ref: whatsnew/3 0 operators-and-special-methods1984899
Ref: 13121984899
Ref: Operators And Special Methods-Footnote-11986583
Node: Builtins1986625
Ref: whatsnew/3 0 builtins1986735
Ref: 131e1986735
Ref: Builtins-Footnote-11989187
Ref: Builtins-Footnote-21989229
Node: Build and C API Changes<7>1989271
Ref: whatsnew/3 0 build-and-c-api-changes1989416
Ref: 13251989416
Ref: Build and C API Changes<7>-Footnote-11990452
Ref: Build and C API Changes<7>-Footnote-21990494
Ref: Build and C API Changes<7>-Footnote-31990536
Node: Performance1990578
Ref: whatsnew/3 0 performance1990717
Ref: 13271990717
Node: Porting To Python 3 01991038
Ref: whatsnew/3 0 porting-to-python-3-01991142
Ref: 13281991142
Node: What’s New in Python 2 71992650
Ref: whatsnew/2 7 doc1992805
Ref: 132a1992805
Ref: whatsnew/2 7 translation-repo1992805
Ref: 132b1992805
Ref: whatsnew/2 7 what-s-new-in-python-2-71992805
Ref: 132c1992805
Node: The Future for Python 2 x1995270
Ref: whatsnew/2 7 the-future-for-python-2-x1995414
Ref: 132d1995414
Ref: whatsnew/2 7 whatsnew27-python311995414
Ref: 132e1995414
Ref: The Future for Python 2 x-Footnote-11998732
Ref: The Future for Python 2 x-Footnote-21998774
Node: Changes to the Handling of Deprecation Warnings1998811
Ref: whatsnew/2 7 changes-to-the-handling-of-deprecation-warnings1998983
Ref: 13301998983
Ref: Changes to the Handling of Deprecation Warnings-Footnote-12000552
Node: Python 3 1 Features2000616
Ref: whatsnew/2 7 python-3-1-features2000814
Ref: 13312000814
Node: PEP 372 Adding an Ordered Dictionary to collections2002739
Ref: whatsnew/2 7 pep-03722002941
Ref: 13322002941
Ref: whatsnew/2 7 pep-372-adding-an-ordered-dictionary-to-collections2002941
Ref: 13352002941
Ref: PEP 372 Adding an Ordered Dictionary to collections-Footnote-12006553
Ref: PEP 372 Adding an Ordered Dictionary to collections-Footnote-22006581
Node: PEP 378 Format Specifier for Thousands Separator<2>2006623
Ref: whatsnew/2 7 pep-03782006859
Ref: 13332006859
Ref: whatsnew/2 7 pep-378-format-specifier-for-thousands-separator2006859
Ref: 13372006859
Ref: PEP 378 Format Specifier for Thousands Separator<2>-Footnote-12008371
Node: PEP 389 The argparse Module for Parsing Command Lines2008413
Ref: whatsnew/2 7 pep-389-the-argparse-module-for-parsing-command-lines2008648
Ref: 13382008648
Ref: PEP 389 The argparse Module for Parsing Command Lines-Footnote-12012666
Node: PEP 391 Dictionary-Based Configuration For Logging2012708
Ref: whatsnew/2 7 pep-391-dictionary-based-configuration-for-logging2012917
Ref: 13392012917
Ref: PEP 391 Dictionary-Based Configuration For Logging-Footnote-12016814
Node: PEP 3106 Dictionary Views2016856
Ref: whatsnew/2 7 pep-3106-dictionary-views2017042
Ref: 13402017042
Ref: PEP 3106 Dictionary Views-Footnote-12019159
Ref: PEP 3106 Dictionary Views-Footnote-22019201
Node: PEP 3137 The memoryview Object2019265
Ref: whatsnew/2 7 pep-3137-the-memoryview-object2019427
Ref: 13412019427
Ref: PEP 3137 The memoryview Object-Footnote-12021092
Ref: PEP 3137 The memoryview Object-Footnote-22021134
Node: Other Language Changes<14>2021198
Ref: whatsnew/2 7 other-language-changes2021359
Ref: 13422021359
Ref: Other Language Changes<14>-Footnote-12031332
Ref: Other Language Changes<14>-Footnote-22031396
Ref: Other Language Changes<14>-Footnote-32031460
Ref: Other Language Changes<14>-Footnote-42031524
Ref: Other Language Changes<14>-Footnote-52031588
Ref: Other Language Changes<14>-Footnote-62031652
Ref: Other Language Changes<14>-Footnote-72031716
Ref: Other Language Changes<14>-Footnote-82031780
Ref: Other Language Changes<14>-Footnote-92031844
Ref: Other Language Changes<14>-Footnote-102031908
Ref: Other Language Changes<14>-Footnote-112031973
Ref: Other Language Changes<14>-Footnote-122032038
Ref: Other Language Changes<14>-Footnote-132032103
Ref: Other Language Changes<14>-Footnote-142032168
Ref: Other Language Changes<14>-Footnote-152032236
Ref: Other Language Changes<14>-Footnote-162032301
Ref: Other Language Changes<14>-Footnote-172032366
Ref: Other Language Changes<14>-Footnote-182032431
Ref: Other Language Changes<14>-Footnote-192032499
Ref: Other Language Changes<14>-Footnote-202032564
Ref: Other Language Changes<14>-Footnote-212032629
Ref: Other Language Changes<14>-Footnote-222032694
Ref: Other Language Changes<14>-Footnote-232032759
Ref: Other Language Changes<14>-Footnote-242032824
Node: Interpreter Changes2032889
Ref: whatsnew/2 7 interpreter-changes2032997
Ref: 13462032997
Ref: whatsnew/2 7 new-27-interpreter2032997
Ref: 13472032997
Ref: Interpreter Changes-Footnote-12033656
Node: Optimizations<13>2033720
Ref: whatsnew/2 7 optimizations2033828
Ref: 13482033828
Ref: Optimizations<13>-Footnote-12038715
Ref: Optimizations<13>-Footnote-22038779
Ref: Optimizations<13>-Footnote-32038843
Ref: Optimizations<13>-Footnote-42038907
Ref: Optimizations<13>-Footnote-52038971
Ref: Optimizations<13>-Footnote-62039035
Ref: Optimizations<13>-Footnote-72039102
Ref: Optimizations<13>-Footnote-82039166
Ref: Optimizations<13>-Footnote-92039230
Ref: Optimizations<13>-Footnote-102039294
Ref: Optimizations<13>-Footnote-112039359
Ref: Optimizations<13>-Footnote-122039424
Ref: Optimizations<13>-Footnote-132039489
Node: New and Improved Modules2039554
Ref: whatsnew/2 7 new-and-improved-modules2039711
Ref: 134a2039711
Ref: New and Improved Modules-Footnote-12075086
Ref: New and Improved Modules-Footnote-22075150
Ref: New and Improved Modules-Footnote-32075214
Ref: New and Improved Modules-Footnote-42075267
Ref: New and Improved Modules-Footnote-52075331
Ref: New and Improved Modules-Footnote-62075395
Ref: New and Improved Modules-Footnote-72075462
Ref: New and Improved Modules-Footnote-82075526
Ref: New and Improved Modules-Footnote-92075590
Ref: New and Improved Modules-Footnote-102075654
Ref: New and Improved Modules-Footnote-112075719
Ref: New and Improved Modules-Footnote-122075784
Ref: New and Improved Modules-Footnote-132075849
Ref: New and Improved Modules-Footnote-142075889
Ref: New and Improved Modules-Footnote-152075954
Ref: New and Improved Modules-Footnote-162076019
Ref: New and Improved Modules-Footnote-172076084
Ref: New and Improved Modules-Footnote-182076149
Ref: New and Improved Modules-Footnote-192076214
Ref: New and Improved Modules-Footnote-202076279
Ref: New and Improved Modules-Footnote-212076344
Ref: New and Improved Modules-Footnote-222076409
Ref: New and Improved Modules-Footnote-232076474
Ref: New and Improved Modules-Footnote-242076539
Ref: New and Improved Modules-Footnote-252076604
Ref: New and Improved Modules-Footnote-262076669
Ref: New and Improved Modules-Footnote-272076737
Ref: New and Improved Modules-Footnote-282076802
Ref: New and Improved Modules-Footnote-292076867
Ref: New and Improved Modules-Footnote-302076932
Ref: New and Improved Modules-Footnote-312076997
Ref: New and Improved Modules-Footnote-322077062
Ref: New and Improved Modules-Footnote-332077127
Ref: New and Improved Modules-Footnote-342077192
Ref: New and Improved Modules-Footnote-352077257
Ref: New and Improved Modules-Footnote-362077322
Ref: New and Improved Modules-Footnote-372077387
Ref: New and Improved Modules-Footnote-382077452
Ref: New and Improved Modules-Footnote-392077517
Ref: New and Improved Modules-Footnote-402077582
Ref: New and Improved Modules-Footnote-412077647
Ref: New and Improved Modules-Footnote-422077712
Ref: New and Improved Modules-Footnote-432077777
Ref: New and Improved Modules-Footnote-442077842
Ref: New and Improved Modules-Footnote-452077907
Ref: New and Improved Modules-Footnote-462077972
Ref: New and Improved Modules-Footnote-472078037
Ref: New and Improved Modules-Footnote-482078102
Ref: New and Improved Modules-Footnote-492078170
Ref: New and Improved Modules-Footnote-502078235
Ref: New and Improved Modules-Footnote-512078300
Ref: New and Improved Modules-Footnote-522078365
Ref: New and Improved Modules-Footnote-532078430
Ref: New and Improved Modules-Footnote-542078495
Ref: New and Improved Modules-Footnote-552078560
Ref: New and Improved Modules-Footnote-562078625
Ref: New and Improved Modules-Footnote-572078690
Ref: New and Improved Modules-Footnote-582078755
Ref: New and Improved Modules-Footnote-592078820
Ref: New and Improved Modules-Footnote-602078885
Ref: New and Improved Modules-Footnote-612078950
Ref: New and Improved Modules-Footnote-622079015
Ref: New and Improved Modules-Footnote-632079080
Ref: New and Improved Modules-Footnote-642079145
Ref: New and Improved Modules-Footnote-652079210
Ref: New and Improved Modules-Footnote-662079275
Ref: New and Improved Modules-Footnote-672079340
Ref: New and Improved Modules-Footnote-682079405
Ref: New and Improved Modules-Footnote-692079470
Ref: New and Improved Modules-Footnote-702079516
Ref: New and Improved Modules-Footnote-712079581
Ref: New and Improved Modules-Footnote-722079646
Ref: New and Improved Modules-Footnote-732079700
Ref: New and Improved Modules-Footnote-742079765
Ref: New and Improved Modules-Footnote-752079830
Ref: New and Improved Modules-Footnote-762079895
Ref: New and Improved Modules-Footnote-772079960
Ref: New and Improved Modules-Footnote-782080025
Ref: New and Improved Modules-Footnote-792080093
Ref: New and Improved Modules-Footnote-802080158
Ref: New and Improved Modules-Footnote-812080223
Ref: New and Improved Modules-Footnote-822080288
Ref: New and Improved Modules-Footnote-832080353
Ref: New and Improved Modules-Footnote-842080418
Ref: New and Improved Modules-Footnote-852080483
Ref: New and Improved Modules-Footnote-862080551
Ref: New and Improved Modules-Footnote-872080619
Ref: New and Improved Modules-Footnote-882080684
Ref: New and Improved Modules-Footnote-892080744
Ref: New and Improved Modules-Footnote-902080804
Ref: New and Improved Modules-Footnote-912080869
Ref: New and Improved Modules-Footnote-922080934
Ref: New and Improved Modules-Footnote-932080999
Ref: New and Improved Modules-Footnote-942081064
Ref: New and Improved Modules-Footnote-952081129
Ref: New and Improved Modules-Footnote-962081194
Ref: New and Improved Modules-Footnote-972081259
Node: New module importlib2081324
Ref: whatsnew/2 7 importlib-section2081434
Ref: 13342081434
Ref: whatsnew/2 7 new-module-importlib2081434
Ref: 13762081434
Node: New module sysconfig2082964
Ref: whatsnew/2 7 new-module-sysconfig2083108
Ref: 13772083108
Node: ttk Themed Widgets for Tk2084432
Ref: whatsnew/2 7 ttk-themed-widgets-for-tk2084579
Ref: 13792084579
Ref: ttk Themed Widgets for Tk-Footnote-12085671
Ref: ttk Themed Widgets for Tk-Footnote-22085735
Node: Updated module unittest2085799
Ref: whatsnew/2 7 unittest-section2085956
Ref: 137a2085956
Ref: whatsnew/2 7 updated-module-unittest2085956
Ref: 137b2085956
Ref: Updated module unittest-Footnote-12094890
Ref: Updated module unittest-Footnote-22094934
Ref: Updated module unittest-Footnote-32094961
Ref: Updated module unittest-Footnote-42094998
Ref: Updated module unittest-Footnote-52095062
Ref: Updated module unittest-Footnote-62095126
Ref: Updated module unittest-Footnote-72095193
Ref: Updated module unittest-Footnote-82095257
Ref: Updated module unittest-Footnote-92095321
Ref: Updated module unittest-Footnote-102095385
Ref: Updated module unittest-Footnote-112095450
Ref: Updated module unittest-Footnote-122095515
Ref: Updated module unittest-Footnote-132095580
Ref: Updated module unittest-Footnote-142095645
Ref: Updated module unittest-Footnote-152095710
Node: Updated module ElementTree 1 32095775
Ref: whatsnew/2 7 elementtree-section2095898
Ref: 13972095898
Ref: whatsnew/2 7 updated-module-elementtree-1-32095898
Ref: 13982095898
Ref: Updated module ElementTree 1 3-Footnote-12099925
Node: Build and C API Changes<8>2099989
Ref: whatsnew/2 7 build-and-c-api-changes2100143
Ref: 139b2100143
Ref: Build and C API Changes<8>-Footnote-12108831
Ref: Build and C API Changes<8>-Footnote-22108944
Ref: Build and C API Changes<8>-Footnote-32109008
Ref: Build and C API Changes<8>-Footnote-42109072
Ref: Build and C API Changes<8>-Footnote-52109136
Ref: Build and C API Changes<8>-Footnote-62109200
Ref: Build and C API Changes<8>-Footnote-72109264
Ref: Build and C API Changes<8>-Footnote-82109328
Ref: Build and C API Changes<8>-Footnote-92109383
Ref: Build and C API Changes<8>-Footnote-102109447
Ref: Build and C API Changes<8>-Footnote-112109512
Ref: Build and C API Changes<8>-Footnote-122109577
Ref: Build and C API Changes<8>-Footnote-132109642
Ref: Build and C API Changes<8>-Footnote-142109710
Ref: Build and C API Changes<8>-Footnote-152109778
Ref: Build and C API Changes<8>-Footnote-162109843
Ref: Build and C API Changes<8>-Footnote-172109908
Ref: Build and C API Changes<8>-Footnote-182109973
Ref: Build and C API Changes<8>-Footnote-192110038
Ref: Build and C API Changes<8>-Footnote-202110103
Ref: Build and C API Changes<8>-Footnote-212110171
Ref: Build and C API Changes<8>-Footnote-222110236
Node: Capsules2110301
Ref: whatsnew/2 7 capsules2110410
Ref: 13a72110410
Ref: whatsnew/2 7 whatsnew27-capsules2110410
Ref: 13a82110410
Ref: Capsules-Footnote-12112414
Node: Port-Specific Changes Windows2112478
Ref: whatsnew/2 7 port-specific-changes-windows2112626
Ref: 13ab2112626
Ref: Port-Specific Changes Windows-Footnote-12114422
Ref: Port-Specific Changes Windows-Footnote-22114486
Ref: Port-Specific Changes Windows-Footnote-32114550
Ref: Port-Specific Changes Windows-Footnote-42114614
Ref: Port-Specific Changes Windows-Footnote-52114681
Ref: Port-Specific Changes Windows-Footnote-62114745
Node: Port-Specific Changes Mac OS X2114809
Ref: whatsnew/2 7 port-specific-changes-mac-os-x2114978
Ref: 13b72114978
Ref: Port-Specific Changes Mac OS X-Footnote-12115968
Ref: Port-Specific Changes Mac OS X-Footnote-22116032
Node: Port-Specific Changes FreeBSD2116097
Ref: whatsnew/2 7 port-specific-changes-freebsd2116228
Ref: 13b82116228
Ref: Port-Specific Changes FreeBSD-Footnote-12116633
Node: Other Changes and Fixes2116697
Ref: whatsnew/2 7 other-changes-and-fixes2116848
Ref: 13b92116848
Ref: Other Changes and Fixes-Footnote-12119043
Ref: Other Changes and Fixes-Footnote-22119107
Ref: Other Changes and Fixes-Footnote-32119174
Ref: Other Changes and Fixes-Footnote-42119238
Ref: Other Changes and Fixes-Footnote-52119302
Node: Porting to Python 2 72119366
Ref: whatsnew/2 7 porting-to-python-2-72119544
Ref: 13bb2119544
Ref: Porting to Python 2 7-Footnote-12125102
Ref: Porting to Python 2 7-Footnote-22125166
Ref: Porting to Python 2 7-Footnote-32125230
Ref: Porting to Python 2 7-Footnote-42125294
Ref: Porting to Python 2 7-Footnote-52125358
Ref: Porting to Python 2 7-Footnote-62125422
Ref: Porting to Python 2 7-Footnote-72125486
Ref: Porting to Python 2 7-Footnote-82125550
Ref: Porting to Python 2 7-Footnote-92125614
Ref: Porting to Python 2 7-Footnote-102125678
Ref: Porting to Python 2 7-Footnote-112125743
Ref: Porting to Python 2 7-Footnote-122125808
Ref: Porting to Python 2 7-Footnote-132125873
Ref: Porting to Python 2 7-Footnote-142125933
Node: New Features Added to Python 2 7 Maintenance Releases2125998
Ref: whatsnew/2 7 new-features-added-to-python-2-7-maintenance-releases2126169
Ref: 13bc2126169
Ref: whatsnew/2 7 py27-maintenance-enhancements2126169
Ref: 132f2126169
Node: Two new environment variables for debug mode2127634
Ref: whatsnew/2 7 two-new-environment-variables-for-debug-mode2127828
Ref: 13bd2127828
Ref: Two new environment variables for debug mode-Footnote-12128509
Ref: Two new environment variables for debug mode-Footnote-22128574
Node: PEP 434 IDLE Enhancement Exception for All Branches2128639
Ref: whatsnew/2 7 pep-434-idle-enhancement-exception-for-all-branches2128894
Ref: 13be2128894
Ref: PEP 434 IDLE Enhancement Exception for All Branches-Footnote-12129414
Node: PEP 466 Network Security Enhancements for Python 2 72129456
Ref: whatsnew/2 7 pep-466-network-security-enhancements-for-python-2-72129715
Ref: 13bf2129715
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-12131947
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-22131989
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-32132031
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-42132096
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-52132161
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-62132203
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-72132268
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-82132333
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-92132388
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-102132430
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-112132496
Ref: PEP 466 Network Security Enhancements for Python 2 7-Footnote-122132562
Node: PEP 477 Backport ensurepip PEP 453 to Python 2 72132628
Ref: whatsnew/2 7 pep-477-backport-ensurepip-pep-453-to-python-2-72132915
Ref: 13c22132915
Ref: PEP 477 Backport ensurepip PEP 453 to Python 2 7-Footnote-12133411
Ref: PEP 477 Backport ensurepip PEP 453 to Python 2 7-Footnote-22133453
Node: Bootstrapping pip By Default<2>2133495
Ref: whatsnew/2 7 bootstrapping-pip-by-default2133644
Ref: 13c32133644
Ref: Bootstrapping pip By Default<2>-Footnote-12135312
Ref: Bootstrapping pip By Default<2>-Footnote-22135354
Node: Documentation Changes<2>2135444
Ref: whatsnew/2 7 documentation-changes2135593
Ref: 13c42135593
Ref: Documentation Changes<2>-Footnote-12136531
Ref: Documentation Changes<2>-Footnote-22136568
Node: PEP 476 Enabling certificate verification by default for stdlib http clients<2>2136610
Ref: whatsnew/2 7 pep-476-enabling-certificate-verification-by-default-for-stdlib-http-clients2136902
Ref: 13c52136902
Ref: PEP 476 Enabling certificate verification by default for stdlib http clients<2>-Footnote-12137999
Node: PEP 493 HTTPS verification migration tools for Python 2 72138041
Ref: whatsnew/2 7 pep-493-https-verification-migration-tools-for-python-2-72138319
Ref: 13c62138319
Ref: PEP 493 HTTPS verification migration tools for Python 2 7-Footnote-12139483
Node: New make regen-all build target<3>2139525
Ref: whatsnew/2 7 new-make-regen-all-build-target2139761
Ref: 13c72139761
Ref: New make regen-all build target<3>-Footnote-12140553
Ref: New make regen-all build target<3>-Footnote-22140621
Node: Removal of make touch build target<3>2140686
Ref: whatsnew/2 7 removal-of-make-touch-build-target2140856
Ref: 13c82140856
Ref: Removal of make touch build target<3>-Footnote-12141291
Node: Acknowledgements2141356
Ref: whatsnew/2 7 acknowledgements2141497
Ref: 13c92141497
Ref: whatsnew/2 7 acks272141497
Ref: 13ca2141497
Node: What’s New in Python 2 62141770
Ref: whatsnew/2 6 doc2141925
Ref: 13cb2141925
Ref: whatsnew/2 6 translation-repo2141925
Ref: 13cc2141925
Ref: whatsnew/2 6 what-s-new-in-python-2-62141925
Ref: 13cd2141925
Ref: whatsnew/2 6 whats-new-in-2-62141925
Ref: 12f52141925
Ref: What’s New in Python 2 6-Footnote-12144989
Node: Python 3 02145031
Ref: whatsnew/2 6 python-3-02145147
Ref: 13ce2145147
Ref: Python 3 0-Footnote-12147259
Ref: Python 3 0-Footnote-22147301
Node: Changes to the Development Process2147343
Ref: whatsnew/2 6 changes-to-the-development-process2147500
Ref: 13cf2147500
Node: New Issue Tracker Roundup2148018
Ref: whatsnew/2 6 new-issue-tracker-roundup2148177
Ref: 13d02148177
Ref: New Issue Tracker Roundup-Footnote-12150227
Ref: New Issue Tracker Roundup-Footnote-22150276
Ref: New Issue Tracker Roundup-Footnote-32150307
Ref: New Issue Tracker Roundup-Footnote-42150347
Ref: New Issue Tracker Roundup-Footnote-52150382
Node: New Documentation Format reStructuredText Using Sphinx2150420
Ref: whatsnew/2 6 new-documentation-format-restructuredtext-using-sphinx2150579
Ref: 13d12150579
Ref: New Documentation Format reStructuredText Using Sphinx-Footnote-12152695
Ref: New Documentation Format reStructuredText Using Sphinx-Footnote-22152754
Ref: New Documentation Format reStructuredText Using Sphinx-Footnote-32152803
Ref: New Documentation Format reStructuredText Using Sphinx-Footnote-42152839
Node: PEP 343 The ‘with’ statement2152879
Ref: whatsnew/2 6 pep-03432153078
Ref: 12f62153078
Ref: whatsnew/2 6 pep-343-the-with-statement2153078
Ref: 13d22153078
Node: Writing Context Managers2156363
Ref: whatsnew/2 6 new-26-context-managers2156486
Ref: 12f72156486
Ref: whatsnew/2 6 writing-context-managers2156486
Ref: 13d42156486
Node: The contextlib module2161003
Ref: whatsnew/2 6 new-module-contextlib2161126
Ref: 12f82161126
Ref: whatsnew/2 6 the-contextlib-module2161126
Ref: 13d52161126
Ref: The contextlib module-Footnote-12163642
Node: PEP 366 Explicit Relative Imports From a Main Module2163684
Ref: whatsnew/2 6 pep-03662163889
Ref: 12f92163889
Ref: whatsnew/2 6 pep-366-explicit-relative-imports-from-a-main-module2163889
Ref: 13d72163889
Node: PEP 370 Per-user site-packages Directory2164648
Ref: whatsnew/2 6 pep-03702164856
Ref: 12fa2164856
Ref: whatsnew/2 6 pep-370-per-user-site-packages-directory2164856
Ref: 13d92164856
Ref: PEP 370 Per-user site-packages Directory-Footnote-12166318
Node: PEP 371 The multiprocessing Package2166360
Ref: whatsnew/2 6 pep-03712166551
Ref: 12fb2166551
Ref: whatsnew/2 6 pep-371-the-multiprocessing-package2166551
Ref: 13dd2166551
Ref: PEP 371 The multiprocessing Package-Footnote-12171763
Node: PEP 3101 Advanced String Formatting2171805
Ref: whatsnew/2 6 pep-31012171984
Ref: 12fc2171984
Ref: whatsnew/2 6 pep-3101-advanced-string-formatting2171984
Ref: 13e72171984
Ref: PEP 3101 Advanced String Formatting-Footnote-12177699
Node: PEP 3105 print As a Function2177741
Ref: whatsnew/2 6 pep-31052177920
Ref: 12fd2177920
Ref: whatsnew/2 6 pep-3105-print-as-a-function2177920
Ref: 13e92177920
Ref: PEP 3105 print As a Function-Footnote-12179043
Node: PEP 3110 Exception-Handling Changes2179085
Ref: whatsnew/2 6 pep-31102179251
Ref: 12fe2179251
Ref: whatsnew/2 6 pep-3110-exception-handling-changes2179251
Ref: 13ea2179251
Ref: PEP 3110 Exception-Handling Changes-Footnote-12180840
Node: PEP 3112 Byte Literals2180882
Ref: whatsnew/2 6 pep-31122181044
Ref: 12ff2181044
Ref: whatsnew/2 6 pep-3112-byte-literals2181044
Ref: 13eb2181044
Ref: PEP 3112 Byte Literals-Footnote-12184094
Node: PEP 3116 New I/O Library2184136
Ref: whatsnew/2 6 pep-31162184295
Ref: 13002184295
Ref: whatsnew/2 6 pep-3116-new-i-o-library2184295
Ref: 13f72184295
Ref: PEP 3116 New I/O Library-Footnote-12188088
Node: PEP 3118 Revised Buffer Protocol2188130
Ref: whatsnew/2 6 pep-31182188297
Ref: 13012188297
Ref: whatsnew/2 6 pep-3118-revised-buffer-protocol2188297
Ref: 14012188297
Ref: PEP 3118 Revised Buffer Protocol-Footnote-12190422
Node: PEP 3119 Abstract Base Classes2190464
Ref: whatsnew/2 6 pep-31192190650
Ref: 13022190650
Ref: whatsnew/2 6 pep-3119-abstract-base-classes2190650
Ref: 14052190650
Ref: PEP 3119 Abstract Base Classes-Footnote-12196037
Node: PEP 3127 Integer Literal Support and Syntax2196079
Ref: whatsnew/2 6 pep-31272196258
Ref: 13032196258
Ref: whatsnew/2 6 pep-3127-integer-literal-support-and-syntax2196258
Ref: 14072196258
Ref: PEP 3127 Integer Literal Support and Syntax-Footnote-12197625
Node: PEP 3129 Class Decorators2197667
Ref: whatsnew/2 6 pep-31292197853
Ref: 13042197853
Ref: whatsnew/2 6 pep-3129-class-decorators2197853
Ref: 14082197853
Ref: PEP 3129 Class Decorators-Footnote-12198253
Node: PEP 3141 A Type Hierarchy for Numbers2198295
Ref: whatsnew/2 6 pep-31412198464
Ref: 13052198464
Ref: whatsnew/2 6 pep-3141-a-type-hierarchy-for-numbers2198464
Ref: 14092198464
Ref: PEP 3141 A Type Hierarchy for Numbers-Footnote-12200660
Ref: PEP 3141 A Type Hierarchy for Numbers-Footnote-22200702
Ref: PEP 3141 A Type Hierarchy for Numbers-Footnote-32200800
Node: The fractions Module2200906
Ref: whatsnew/2 6 the-fractions-module2201000
Ref: 140d2201000
Node: Other Language Changes<15>2202607
Ref: whatsnew/2 6 other-language-changes2202778
Ref: 140e2202778
Ref: Other Language Changes<15>-Footnote-12211596
Ref: Other Language Changes<15>-Footnote-22211663
Ref: Other Language Changes<15>-Footnote-32211727
Ref: Other Language Changes<15>-Footnote-42211794
Ref: Other Language Changes<15>-Footnote-52211858
Ref: Other Language Changes<15>-Footnote-62211922
Ref: Other Language Changes<15>-Footnote-72211986
Ref: Other Language Changes<15>-Footnote-82212050
Ref: Other Language Changes<15>-Footnote-92212114
Ref: Other Language Changes<15>-Footnote-102212178
Ref: Other Language Changes<15>-Footnote-112212243
Ref: Other Language Changes<15>-Footnote-122212308
Ref: Other Language Changes<15>-Footnote-132212376
Ref: Other Language Changes<15>-Footnote-142212444
Ref: Other Language Changes<15>-Footnote-152212512
Ref: Other Language Changes<15>-Footnote-162212580
Node: Optimizations<14>2212648
Ref: whatsnew/2 6 optimizations2212759
Ref: 14162212759
Ref: Optimizations<14>-Footnote-12215627
Ref: Optimizations<14>-Footnote-22215694
Ref: Optimizations<14>-Footnote-32215761
Ref: Optimizations<14>-Footnote-42215825
Node: Interpreter Changes<2>2215889
Ref: whatsnew/2 6 interpreter-changes2216000
Ref: 14182216000
Ref: whatsnew/2 6 new-26-interpreter2216000
Ref: 14192216000
Node: New and Improved Modules<2>2217590
Ref: whatsnew/2 6 new-and-improved-modules2217749
Ref: 141d2217749
Ref: New and Improved Modules<2>-Footnote-12260266
Ref: New and Improved Modules<2>-Footnote-22260333
Ref: New and Improved Modules<2>-Footnote-32260386
Ref: New and Improved Modules<2>-Footnote-42260450
Ref: New and Improved Modules<2>-Footnote-52260516
Ref: New and Improved Modules<2>-Footnote-62260580
Ref: New and Improved Modules<2>-Footnote-72260647
Ref: New and Improved Modules<2>-Footnote-82260711
Ref: New and Improved Modules<2>-Footnote-92260765
Ref: New and Improved Modules<2>-Footnote-102260832
Ref: New and Improved Modules<2>-Footnote-112260900
Ref: New and Improved Modules<2>-Footnote-122260968
Ref: New and Improved Modules<2>-Footnote-132261033
Ref: New and Improved Modules<2>-Footnote-142261098
Ref: New and Improved Modules<2>-Footnote-152261165
Ref: New and Improved Modules<2>-Footnote-162261230
Ref: New and Improved Modules<2>-Footnote-172261298
Ref: New and Improved Modules<2>-Footnote-182261363
Ref: New and Improved Modules<2>-Footnote-192261431
Ref: New and Improved Modules<2>-Footnote-202261499
Ref: New and Improved Modules<2>-Footnote-212261567
Ref: New and Improved Modules<2>-Footnote-222261634
Ref: New and Improved Modules<2>-Footnote-232261702
Ref: New and Improved Modules<2>-Footnote-242261770
Ref: New and Improved Modules<2>-Footnote-252261835
Ref: New and Improved Modules<2>-Footnote-262261900
Ref: New and Improved Modules<2>-Footnote-272261968
Ref: New and Improved Modules<2>-Footnote-282262036
Ref: New and Improved Modules<2>-Footnote-292262103
Ref: New and Improved Modules<2>-Footnote-302262168
Ref: New and Improved Modules<2>-Footnote-312262233
Ref: New and Improved Modules<2>-Footnote-322262298
Ref: New and Improved Modules<2>-Footnote-332262363
Ref: New and Improved Modules<2>-Footnote-342262428
Ref: New and Improved Modules<2>-Footnote-352262493
Ref: New and Improved Modules<2>-Footnote-362262558
Ref: New and Improved Modules<2>-Footnote-372262618
Ref: New and Improved Modules<2>-Footnote-382262685
Ref: New and Improved Modules<2>-Footnote-392262745
Ref: New and Improved Modules<2>-Footnote-402262812
Ref: New and Improved Modules<2>-Footnote-412262877
Ref: New and Improved Modules<2>-Footnote-422262944
Ref: New and Improved Modules<2>-Footnote-432263012
Ref: New and Improved Modules<2>-Footnote-442263077
Ref: New and Improved Modules<2>-Footnote-452263142
Ref: New and Improved Modules<2>-Footnote-462263207
Ref: New and Improved Modules<2>-Footnote-472263275
Ref: New and Improved Modules<2>-Footnote-482263340
Ref: New and Improved Modules<2>-Footnote-492263405
Ref: New and Improved Modules<2>-Footnote-502263473
Ref: New and Improved Modules<2>-Footnote-512263538
Ref: New and Improved Modules<2>-Footnote-522263606
Ref: New and Improved Modules<2>-Footnote-532263671
Ref: New and Improved Modules<2>-Footnote-542263739
Ref: New and Improved Modules<2>-Footnote-552263804
Ref: New and Improved Modules<2>-Footnote-562263872
Ref: New and Improved Modules<2>-Footnote-572263937
Ref: New and Improved Modules<2>-Footnote-582264005
Ref: New and Improved Modules<2>-Footnote-592264073
Ref: New and Improved Modules<2>-Footnote-602264138
Ref: New and Improved Modules<2>-Footnote-612264203
Ref: New and Improved Modules<2>-Footnote-622264270
Ref: New and Improved Modules<2>-Footnote-632264338
Node: The ast module2264406
Ref: whatsnew/2 6 the-ast-module2264519
Ref: 14322264519
Node: The future_builtins module2267180
Ref: whatsnew/2 6 the-future-builtins-module2267344
Ref: 14332267344
Node: The json module JavaScript Object Notation2268444
Ref: whatsnew/2 6 the-json-module-javascript-object-notation2268636
Ref: 14352268636
Node: The plistlib module A Property-List Parser2269648
Ref: whatsnew/2 6 the-plistlib-module-a-property-list-parser2269833
Ref: 14362269833
Node: ctypes Enhancements2271204
Ref: whatsnew/2 6 ctypes-enhancements2271367
Ref: 14372271367
Ref: ctypes Enhancements-Footnote-12273134
Ref: ctypes Enhancements-Footnote-22273201
Node: Improved SSL Support2273265
Ref: whatsnew/2 6 improved-ssl-support2273377
Ref: 14382273377
Ref: Improved SSL Support-Footnote-12274324
Node: Deprecations and Removals2274357
Ref: whatsnew/2 6 deprecations-and-removals2274516
Ref: 14392274516
Ref: Deprecations and Removals-Footnote-12276378
Node: Build and C API Changes<9>2276420
Ref: whatsnew/2 6 build-and-c-api-changes2276573
Ref: 143b2276573
Ref: Build and C API Changes<9>-Footnote-12284109
Ref: Build and C API Changes<9>-Footnote-22284164
Ref: Build and C API Changes<9>-Footnote-32284219
Ref: Build and C API Changes<9>-Footnote-42284283
Ref: Build and C API Changes<9>-Footnote-52284350
Ref: Build and C API Changes<9>-Footnote-62284414
Ref: Build and C API Changes<9>-Footnote-72284478
Node: Port-Specific Changes Windows<2>2284545
Ref: whatsnew/2 6 port-specific-changes-windows2284682
Ref: 14422284682
Ref: Port-Specific Changes Windows<2>-Footnote-12287152
Ref: Port-Specific Changes Windows<2>-Footnote-22287218
Ref: Port-Specific Changes Windows<2>-Footnote-32287285
Node: Port-Specific Changes Mac OS X<2>2287349
Ref: whatsnew/2 6 port-specific-changes-mac-os-x2287521
Ref: 14472287521
Ref: Port-Specific Changes Mac OS X<2>-Footnote-12288792
Node: Port-Specific Changes IRIX2288859
Ref: whatsnew/2 6 port-specific-changes-irix2288990
Ref: 14482288990
Node: Porting to Python 2 62289509
Ref: whatsnew/2 6 porting-to-python-2-62289656
Ref: 14492289656
Ref: Porting to Python 2 6-Footnote-12293461
Ref: Porting to Python 2 6-Footnote-22293528
Ref: Porting to Python 2 6-Footnote-32293595
Node: Acknowledgements<2>2293662
Ref: whatsnew/2 6 acknowledgements2293774
Ref: 144b2293774
Ref: whatsnew/2 6 acks2293774
Ref: 144c2293774
Node: What’s New in Python 2 52294116
Ref: whatsnew/2 5 doc2294271
Ref: 144d2294271
Ref: whatsnew/2 5 translation-repo2294271
Ref: 144e2294271
Ref: whatsnew/2 5 what-s-new-in-python-2-52294271
Ref: 144f2294271
Ref: What’s New in Python 2 5-Footnote-12297927
Node: PEP 308 Conditional Expressions2297969
Ref: whatsnew/2 5 pep-3082298108
Ref: 14502298108
Ref: whatsnew/2 5 pep-308-conditional-expressions2298108
Ref: 14552298108
Ref: PEP 308 Conditional Expressions-Footnote-12301592
Ref: PEP 308 Conditional Expressions-Footnote-22301634
Node: PEP 309 Partial Function Application2301676
Ref: whatsnew/2 5 pep-3092301874
Ref: 14562301874
Ref: whatsnew/2 5 pep-309-partial-function-application2301874
Ref: 14572301874
Ref: PEP 309 Partial Function Application-Footnote-12304721
Node: PEP 314 Metadata for Python Software Packages v1 12304763
Ref: whatsnew/2 5 pep-3142304967
Ref: 14582304967
Ref: whatsnew/2 5 pep-314-metadata-for-python-software-packages-v1-12304967
Ref: 14592304967
Ref: PEP 314 Metadata for Python Software Packages v1 1-Footnote-12306801
Node: PEP 328 Absolute and Relative Imports2306843
Ref: whatsnew/2 5 pep-3282307047
Ref: 14532307047
Ref: whatsnew/2 5 pep-328-absolute-and-relative-imports2307047
Ref: 145a2307047
Ref: PEP 328 Absolute and Relative Imports-Footnote-12310859
Ref: PEP 328 Absolute and Relative Imports-Footnote-22310901
Node: PEP 338 Executing Modules as Scripts2310943
Ref: whatsnew/2 5 pep-3382311131
Ref: 145b2311131
Ref: whatsnew/2 5 pep-338-executing-modules-as-scripts2311131
Ref: 145c2311131
Ref: PEP 338 Executing Modules as Scripts-Footnote-12312026
Node: PEP 341 Unified try/except/finally2312068
Ref: whatsnew/2 5 pep-3412312249
Ref: 14542312249
Ref: whatsnew/2 5 pep-341-unified-try-except-finally2312249
Ref: 145d2312249
Ref: PEP 341 Unified try/except/finally-Footnote-12314016
Node: PEP 342 New Generator Features2314058
Ref: whatsnew/2 5 pep-3422314238
Ref: 14522314238
Ref: whatsnew/2 5 pep-342-new-generator-features2314238
Ref: 145e2314238
Ref: PEP 342 New Generator Features-Footnote-12320883
Ref: PEP 342 New Generator Features-Footnote-22320925
Ref: PEP 342 New Generator Features-Footnote-32320967
Ref: PEP 342 New Generator Features-Footnote-42321009
Ref: PEP 342 New Generator Features-Footnote-52321051
Node: PEP 343 The ‘with’ statement<2>2321093
Ref: whatsnew/2 5 pep-3432321278
Ref: 14512321278
Ref: whatsnew/2 5 pep-343-the-with-statement2321278
Ref: 145f2321278
Node: Writing Context Managers<2>2324300
Ref: whatsnew/2 5 new-25-context-managers2324432
Ref: 14602324432
Ref: whatsnew/2 5 writing-context-managers2324432
Ref: 14612324432
Node: The contextlib module<2>2328831
Ref: whatsnew/2 5 contextlibmod2328963
Ref: 14622328963
Ref: whatsnew/2 5 the-contextlib-module2328963
Ref: 14632328963
Ref: The contextlib module<2>-Footnote-12331451
Node: PEP 352 Exceptions as New-Style Classes2331493
Ref: whatsnew/2 5 pep-3522331687
Ref: 14642331687
Ref: whatsnew/2 5 pep-352-exceptions-as-new-style-classes2331687
Ref: 14652331687
Ref: PEP 352 Exceptions as New-Style Classes-Footnote-12334159
Node: PEP 353 Using ssize_t as the index type2334201
Ref: whatsnew/2 5 pep-3532334394
Ref: 14662334394
Ref: whatsnew/2 5 pep-353-using-ssize-t-as-the-index-type2334394
Ref: 14672334394
Ref: PEP 353 Using ssize_t as the index type-Footnote-12337271
Ref: PEP 353 Using ssize_t as the index type-Footnote-22337313
Node: PEP 357 The ‘__index__’ method2337355
Ref: whatsnew/2 5 pep-3572337535
Ref: 14692337535
Ref: whatsnew/2 5 pep-357-the-index-method2337535
Ref: 146a2337535
Ref: PEP 357 The ‘__index__’ method-Footnote-12339244
Node: Other Language Changes<16>2339286
Ref: whatsnew/2 5 other-lang2339459
Ref: 146d2339459
Ref: whatsnew/2 5 other-language-changes2339459
Ref: 146e2339459
Ref: Other Language Changes<16>-Footnote-12346371
Node: Interactive Interpreter Changes2346413
Ref: whatsnew/2 5 interactive2346533
Ref: 14742346533
Ref: whatsnew/2 5 interactive-interpreter-changes2346533
Ref: 14752346533
Node: Optimizations<15>2347310
Ref: whatsnew/2 5 optimizations2347430
Ref: 14772347430
Ref: whatsnew/2 5 opts2347430
Ref: 14782347430
Node: New Improved and Removed Modules2351248
Ref: whatsnew/2 5 modules2351414
Ref: 14792351414
Ref: whatsnew/2 5 new-improved-and-removed-modules2351414
Ref: 147a2351414
Ref: New Improved and Removed Modules-Footnote-12375887
Ref: New Improved and Removed Modules-Footnote-22375929
Ref: New Improved and Removed Modules-Footnote-32375988
Node: The ctypes package2376047
Ref: whatsnew/2 5 module-ctypes2376166
Ref: 14842376166
Ref: whatsnew/2 5 the-ctypes-package2376166
Ref: 14852376166
Node: The ElementTree package2379421
Ref: whatsnew/2 5 module-etree2379568
Ref: 14872379568
Ref: whatsnew/2 5 the-elementtree-package2379568
Ref: 14882379568
Node: The hashlib package2384866
Ref: whatsnew/2 5 module-hashlib2385014
Ref: 14892385014
Ref: whatsnew/2 5 the-hashlib-package2385014
Ref: 148a2385014
Node: The sqlite3 package2386593
Ref: whatsnew/2 5 module-sqlite2386737
Ref: 148b2386737
Ref: whatsnew/2 5 the-sqlite3-package2386737
Ref: 148c2386737
Ref: The sqlite3 package-Footnote-12390748
Ref: The sqlite3 package-Footnote-22390790
Node: The wsgiref package2390832
Ref: whatsnew/2 5 module-wsgiref2390948
Ref: 148d2390948
Ref: whatsnew/2 5 the-wsgiref-package2390948
Ref: 148e2390948
Ref: The wsgiref package-Footnote-12391931
Ref: The wsgiref package-Footnote-22391973
Node: Build and C API Changes<10>2392015
Ref: whatsnew/2 5 build-and-c-api-changes2392176
Ref: 148f2392176
Ref: whatsnew/2 5 build-api2392176
Ref: 14902392176
Ref: Build and C API Changes<10>-Footnote-12399210
Ref: Build and C API Changes<10>-Footnote-22399252
Ref: Build and C API Changes<10>-Footnote-32399294
Node: Port-Specific Changes2399336
Ref: whatsnew/2 5 port-specific-changes2399421
Ref: 149c2399421
Ref: whatsnew/2 5 ports2399421
Ref: 149d2399421
Ref: Port-Specific Changes-Footnote-12400098
Node: Porting to Python 2 52400162
Ref: whatsnew/2 5 porting2400310
Ref: 149e2400310
Ref: whatsnew/2 5 porting-to-python-2-52400310
Ref: 149f2400310
Ref: Porting to Python 2 5-Footnote-12403133
Node: Acknowledgements<3>2403175
Ref: whatsnew/2 5 acknowledgements2403287
Ref: 14a02403287
Node: What’s New in Python 2 42403781
Ref: whatsnew/2 4 doc2403936
Ref: 14a12403936
Ref: whatsnew/2 4 translation-repo2403936
Ref: 14a22403936
Ref: whatsnew/2 4 what-s-new-in-python-2-42403936
Ref: 14a32403936
Node: PEP 218 Built-In Set Objects2406041
Ref: whatsnew/2 4 pep-218-built-in-set-objects2406184
Ref: 14a42406184
Ref: PEP 218 Built-In Set Objects-Footnote-12408420
Node: PEP 237 Unifying Long Integers and Integers2408462
Ref: whatsnew/2 4 pep-237-unifying-long-integers-and-integers2408643
Ref: 14a52408643
Ref: PEP 237 Unifying Long Integers and Integers-Footnote-12409684
Node: PEP 289 Generator Expressions2409726
Ref: whatsnew/2 4 pep-289-generator-expressions2409915
Ref: 14a62409915
Ref: PEP 289 Generator Expressions-Footnote-12412187
Node: PEP 292 Simpler String Substitutions2412229
Ref: whatsnew/2 4 pep-292-simpler-string-substitutions2412419
Ref: 14a72412419
Ref: PEP 292 Simpler String Substitutions-Footnote-12414218
Node: PEP 318 Decorators for Functions and Methods2414260
Ref: whatsnew/2 4 pep-318-decorators-for-functions-and-methods2414446
Ref: 14a82414446
Ref: PEP 318 Decorators for Functions and Methods-Footnote-12418975
Ref: PEP 318 Decorators for Functions and Methods-Footnote-22419017
Node: PEP 322 Reverse Iteration2419059
Ref: whatsnew/2 4 pep-322-reverse-iteration2419238
Ref: 14aa2419238
Ref: PEP 322 Reverse Iteration-Footnote-12420200
Node: PEP 324 New subprocess Module2420242
Ref: whatsnew/2 4 pep-324-new-subprocess-module2420402
Ref: 14ab2420402
Ref: PEP 324 New subprocess Module-Footnote-12424185
Node: PEP 327 Decimal Data Type2424227
Ref: whatsnew/2 4 pep-327-decimal-data-type2424388
Ref: 14ad2424388
Node: Why is Decimal needed?2424960
Ref: whatsnew/2 4 why-is-decimal-needed2425069
Ref: 14ae2425069
Node: The Decimal type2427653
Ref: whatsnew/2 4 the-decimal-type2427787
Ref: 14af2427787
Node: The Context type2430959
Ref: whatsnew/2 4 the-context-type2431062
Ref: 14b02431062
Ref: The Context type-Footnote-12433669
Ref: The Context type-Footnote-22433711
Node: PEP 328 Multi-line Imports2433794
Ref: whatsnew/2 4 pep-328-multi-line-imports2433977
Ref: 14b12433977
Ref: PEP 328 Multi-line Imports-Footnote-12435471
Node: PEP 331 Locale-Independent Float/String Conversions2435513
Ref: whatsnew/2 4 pep-331-locale-independent-float-string-conversions2435697
Ref: 14b22435697
Ref: PEP 331 Locale-Independent Float/String Conversions-Footnote-12437424
Ref: PEP 331 Locale-Independent Float/String Conversions-Footnote-22437514
Node: Other Language Changes<17>2437556
Ref: whatsnew/2 4 other-language-changes2437752
Ref: 14b32437752
Ref: Other Language Changes<17>-Footnote-12444736
Ref: Other Language Changes<17>-Footnote-22444778
Ref: Other Language Changes<17>-Footnote-32444820
Ref: Other Language Changes<17>-Footnote-42444862
Ref: Other Language Changes<17>-Footnote-52444904
Ref: Other Language Changes<17>-Footnote-62444946
Node: Optimizations<16>2444988
Ref: whatsnew/2 4 optimizations2445068
Ref: 14b52445068
Node: New Improved and Deprecated Modules<3>2447823
Ref: whatsnew/2 4 new-improved-and-deprecated-modules2447995
Ref: 14b62447995
Ref: New Improved and Deprecated Modules<3>-Footnote-12465298
Node: cookielib2465357
Ref: whatsnew/2 4 cookielib2465460
Ref: 14ba2465460
Node: doctest<5>2466400
Ref: whatsnew/2 4 doctest2466503
Ref: 14bb2466503
Node: Build and C API Changes<11>2469243
Ref: whatsnew/2 4 build-and-c-api-changes2469410
Ref: 14c12469410
Node: Port-Specific Changes<2>2472045
Ref: whatsnew/2 4 port-specific-changes2472133
Ref: 14c82472133
Node: Porting to Python 2 42472312
Ref: whatsnew/2 4 porting-to-python-2-42472460
Ref: 14c92472460
Node: Acknowledgements<4>2474428
Ref: whatsnew/2 4 acknowledgements2474540
Ref: 14cb2474540
Ref: whatsnew/2 4 acks2474540
Ref: 14cc2474540
Node: What’s New in Python 2 32474873
Ref: whatsnew/2 3 doc2475028
Ref: 14cd2475028
Ref: whatsnew/2 3 translation-repo2475028
Ref: 14ce2475028
Ref: whatsnew/2 3 what-s-new-in-python-2-32475028
Ref: 14cf2475028
Node: PEP 218 A Standard Set Datatype2478047
Ref: whatsnew/2 3 pep-218-a-standard-set-datatype2478175
Ref: 14d12478175
Ref: PEP 218 A Standard Set Datatype-Footnote-12480692
Node: PEP 255 Simple Generators2480734
Ref: whatsnew/2 3 pep-255-simple-generators2480900
Ref: 14d62480900
Ref: whatsnew/2 3 section-generators2480900
Ref: 14d72480900
Ref: PEP 255 Simple Generators-Footnote-12487084
Ref: PEP 255 Simple Generators-Footnote-22487126
Node: PEP 263 Source Code Encodings2487168
Ref: whatsnew/2 3 pep-263-source-code-encodings2487346
Ref: 14d82487346
Ref: whatsnew/2 3 section-encodings2487346
Ref: 14d92487346
Ref: PEP 263 Source Code Encodings-Footnote-12488558
Node: PEP 273 Importing Modules from ZIP Archives2488600
Ref: whatsnew/2 3 pep-273-importing-modules-from-zip-archives2488801
Ref: 14da2488801
Ref: PEP 273 Importing Modules from ZIP Archives-Footnote-12490835
Ref: PEP 273 Importing Modules from ZIP Archives-Footnote-22490877
Ref: PEP 273 Importing Modules from ZIP Archives-Footnote-32490919
Node: PEP 277 Unicode file name support for Windows NT2490961
Ref: whatsnew/2 3 pep-277-unicode-file-name-support-for-windows-nt2491166
Ref: 14dc2491166
Ref: PEP 277 Unicode file name support for Windows NT-Footnote-12492648
Node: PEP 278 Universal Newline Support2492690
Ref: whatsnew/2 3 pep-278-universal-newline-support2492869
Ref: 14de2492869
Ref: PEP 278 Universal Newline Support-Footnote-12494380
Node: PEP 279 enumerate2494422
Ref: whatsnew/2 3 pep-279-enumerate2494580
Ref: 14df2494580
Ref: whatsnew/2 3 section-enumerate2494580
Ref: 14e02494580
Ref: PEP 279 enumerate-Footnote-12495438
Node: PEP 282 The logging Package2495480
Ref: whatsnew/2 3 pep-282-the-logging-package2495627
Ref: 14e12495627
Ref: PEP 282 The logging Package-Footnote-12500387
Ref: PEP 282 The logging Package-Footnote-22500429
Node: PEP 285 A Boolean Type2500471
Ref: whatsnew/2 3 pep-285-a-boolean-type2500639
Ref: 14e72500639
Ref: whatsnew/2 3 section-bool2500639
Ref: 14e82500639
Ref: PEP 285 A Boolean Type-Footnote-12503075
Ref: PEP 285 A Boolean Type-Footnote-22503117
Node: PEP 293 Codec Error Handling Callbacks2503159
Ref: whatsnew/2 3 pep-293-codec-error-handling-callbacks2503348
Ref: 14e92503348
Ref: PEP 293 Codec Error Handling Callbacks-Footnote-12504901
Node: PEP 301 Package Index and Metadata for Distutils2504943
Ref: whatsnew/2 3 pep-301-package-index-and-metadata-for-distutils2505134
Ref: 14ec2505134
Ref: whatsnew/2 3 section-pep3012505134
Ref: 14ed2505134
Ref: PEP 301 Package Index and Metadata for Distutils-Footnote-12506778
Ref: PEP 301 Package Index and Metadata for Distutils-Footnote-22506814
Node: PEP 302 New Import Hooks2506856
Ref: whatsnew/2 3 pep-302-new-import-hooks2507038
Ref: 14ee2507038
Ref: whatsnew/2 3 section-pep3022507038
Ref: 14db2507038
Ref: PEP 302 New Import Hooks-Footnote-12509645
Ref: PEP 302 New Import Hooks-Footnote-22509687
Ref: PEP 302 New Import Hooks-Footnote-32509729
Node: PEP 305 Comma-separated Files2509771
Ref: whatsnew/2 3 pep-305-comma-separated-files2509932
Ref: 14ef2509932
Ref: whatsnew/2 3 section-pep3052509932
Ref: 14f02509932
Ref: PEP 305 Comma-separated Files-Footnote-12511413
Node: PEP 307 Pickle Enhancements2511455
Ref: whatsnew/2 3 pep-307-pickle-enhancements2511607
Ref: 14f12511607
Ref: whatsnew/2 3 section-pep3072511607
Ref: 14f22511607
Ref: PEP 307 Pickle Enhancements-Footnote-12513580
Ref: PEP 307 Pickle Enhancements-Footnote-22513622
Ref: PEP 307 Pickle Enhancements-Footnote-32513664
Node: Extended Slices2513706
Ref: whatsnew/2 3 extended-slices2513855
Ref: 14f52513855
Ref: whatsnew/2 3 section-slices2513855
Ref: 14f62513855
Node: Other Language Changes<18>2517247
Ref: whatsnew/2 3 other-language-changes2517407
Ref: 14f72517407
Ref: Other Language Changes<18>-Footnote-12525199
Node: String Changes2525272
Ref: whatsnew/2 3 string-changes2525375
Ref: 14fd2525375
Node: Optimizations<17>2527881
Ref: whatsnew/2 3 optimizations2527984
Ref: 15022527984
Node: New Improved and Deprecated Modules<4>2529447
Ref: whatsnew/2 3 new-improved-and-deprecated-modules2529631
Ref: 15042529631
Ref: New Improved and Deprecated Modules<4>-Footnote-12554388
Node: Date/Time Type2554428
Ref: whatsnew/2 3 date-time-type2554545
Ref: 15182554545
Node: The optparse Module2556847
Ref: whatsnew/2 3 the-optparse-module2556964
Ref: 151b2556964
Node: Pymalloc A Specialized Object Allocator2559038
Ref: whatsnew/2 3 pymalloc-a-specialized-object-allocator2559223
Ref: 151e2559223
Ref: whatsnew/2 3 section-pymalloc2559223
Ref: 151f2559223
Node: Build and C API Changes<12>2563125
Ref: whatsnew/2 3 build-and-c-api-changes2563298
Ref: 15212563298
Node: Port-Specific Changes<3>2566718
Ref: whatsnew/2 3 port-specific-changes2566806
Ref: 15272566806
Node: Other Changes and Fixes<2>2568041
Ref: whatsnew/2 3 other-changes-and-fixes2568196
Ref: 15282568196
Ref: whatsnew/2 3 section-other2568196
Ref: 15032568196
Node: Porting to Python 2 32570701
Ref: whatsnew/2 3 porting-to-python-2-32570848
Ref: 152b2570848
Node: Acknowledgements<5>2573657
Ref: whatsnew/2 3 acknowledgements2573769
Ref: 152c2573769
Ref: whatsnew/2 3 acks2573769
Ref: 152d2573769
Node: What’s New in Python 2 22574390
Ref: whatsnew/2 2 doc2574545
Ref: 152e2574545
Ref: whatsnew/2 2 translation-repo2574545
Ref: 152f2574545
Ref: whatsnew/2 2 what-s-new-in-python-2-22574545
Ref: 15302574545
Node: Introduction2575280
Ref: whatsnew/2 2 introduction2575403
Ref: 15312575403
Ref: Introduction-Footnote-12576375
Ref: Introduction-Footnote-22576424
Node: PEPs 252 and 253 Type and Class Changes2576473
Ref: whatsnew/2 2 peps-252-and-253-type-and-class-changes2576622
Ref: 15322576622
Node: Old and New Classes2580062
Ref: whatsnew/2 2 old-and-new-classes2580177
Ref: 15352580177
Ref: Old and New Classes-Footnote-12582577
Node: Descriptors2582619
Ref: whatsnew/2 2 descriptors2582780
Ref: 15362582780
Node: Multiple Inheritance The Diamond Rule2586647
Ref: whatsnew/2 2 multiple-inheritance-the-diamond-rule2586805
Ref: 15382586805
Ref: Multiple Inheritance The Diamond Rule-Footnote-12589690
Node: Attribute Access2589732
Ref: whatsnew/2 2 attribute-access2589892
Ref: 15392589892
Node: Related Links2593686
Ref: whatsnew/2 2 related-links2593800
Ref: 153b2593800
Ref: whatsnew/2 2 sect-rellinks2593800
Ref: 15342593800
Ref: Related Links-Footnote-12595279
Ref: Related Links-Footnote-22595321
Ref: Related Links-Footnote-32595363
Ref: Related Links-Footnote-42595405
Ref: Related Links-Footnote-52595447
Node: PEP 234 Iterators2595489
Ref: whatsnew/2 2 pep-234-iterators2595654
Ref: 153d2595654
Ref: PEP 234 Iterators-Footnote-12600515
Node: PEP 255 Simple Generators<2>2600557
Ref: whatsnew/2 2 pep-255-simple-generators2600729
Ref: 15402600729
Ref: PEP 255 Simple Generators<2>-Footnote-12606788
Ref: PEP 255 Simple Generators<2>-Footnote-22606830
Node: PEP 237 Unifying Long Integers and Integers<2>2606872
Ref: whatsnew/2 2 pep-237-unifying-long-integers-and-integers2607065
Ref: 15412607065
Ref: PEP 237 Unifying Long Integers and Integers<2>-Footnote-12608790
Node: PEP 238 Changing the Division Operator2608832
Ref: whatsnew/2 2 pep-238-changing-the-division-operator2609012
Ref: 15422609012
Ref: PEP 238 Changing the Division Operator-Footnote-12612666
Ref: PEP 238 Changing the Division Operator-Footnote-22612708
Ref: PEP 238 Changing the Division Operator-Footnote-32612750
Node: Unicode Changes2612792
Ref: whatsnew/2 2 unicode-changes2612947
Ref: 15442612947
Ref: Unicode Changes-Footnote-12615579
Ref: Unicode Changes-Footnote-22615621
Node: PEP 227 Nested Scopes2615663
Ref: whatsnew/2 2 pep-227-nested-scopes2615807
Ref: 15452615807
Ref: PEP 227 Nested Scopes-Footnote-12620153
Node: New and Improved Modules<3>2620195
Ref: whatsnew/2 2 new-and-improved-modules2620353
Ref: 15462620353
Ref: New and Improved Modules<3>-Footnote-12627047
Ref: New and Improved Modules<3>-Footnote-22627106
Ref: New and Improved Modules<3>-Footnote-32627165
Ref: New and Improved Modules<3>-Footnote-42627224
Ref: New and Improved Modules<3>-Footnote-52627283
Node: Interpreter Changes and Fixes2627341
Ref: whatsnew/2 2 interpreter-changes-and-fixes2627504
Ref: 154b2627504
Node: Other Changes and Fixes<3>2632276
Ref: whatsnew/2 2 other-changes-and-fixes2632431
Ref: 155c2632431
Ref: Other Changes and Fixes<3>-Footnote-12639105
Node: Acknowledgements<6>2639147
Ref: whatsnew/2 2 acknowledgements2639264
Ref: 155f2639264
Node: What’s New in Python 2 12639865
Ref: whatsnew/2 1 doc2640020
Ref: 15602640020
Ref: whatsnew/2 1 translation-repo2640020
Ref: 15612640020
Ref: whatsnew/2 1 what-s-new-in-python-2-12640020
Ref: 15622640020
Node: Introduction<2>2641025
Ref: whatsnew/2 1 introduction2641136
Ref: 15632641136
Node: PEP 227 Nested Scopes<2>2642232
Ref: whatsnew/2 1 pep-227-nested-scopes2642381
Ref: 15642642381
Ref: PEP 227 Nested Scopes<2>-Footnote-12646740
Ref: PEP 227 Nested Scopes<2>-Footnote-22646782
Ref: PEP 227 Nested Scopes<2>-Footnote-32646824
Node: PEP 236 __future__ Directives2646866
Ref: whatsnew/2 1 pep-236-future-directives2647024
Ref: 15652647024
Ref: PEP 236 __future__ Directives-Footnote-12648261
Node: PEP 207 Rich Comparisons2648303
Ref: whatsnew/2 1 pep-207-rich-comparisons2648462
Ref: 15662648462
Ref: PEP 207 Rich Comparisons-Footnote-12651870
Ref: PEP 207 Rich Comparisons-Footnote-22651912
Node: PEP 230 Warning Framework2651954
Ref: whatsnew/2 1 pep-230-warning-framework2652108
Ref: 15682652108
Ref: PEP 230 Warning Framework-Footnote-12655389
Ref: PEP 230 Warning Framework-Footnote-22655431
Node: PEP 229 New Build System2655473
Ref: whatsnew/2 1 pep-229-new-build-system2655626
Ref: 156a2655626
Ref: PEP 229 New Build System-Footnote-12657546
Node: PEP 205 Weak References2657588
Ref: whatsnew/2 1 pep-205-weak-references2657743
Ref: 156b2657743
Ref: PEP 205 Weak References-Footnote-12660856
Node: PEP 232 Function Attributes2660898
Ref: whatsnew/2 1 pep-232-function-attributes2661084
Ref: 156c2661084
Ref: PEP 232 Function Attributes-Footnote-12662598
Node: PEP 235 Importing Modules on Case-Insensitive Platforms2662640
Ref: whatsnew/2 1 pep-235-importing-modules-on-case-insensitive-platforms2662835
Ref: 156d2662835
Node: PEP 217 Interactive Display Hook2663738
Ref: whatsnew/2 1 pep-217-interactive-display-hook2663932
Ref: 156e2663932
Ref: PEP 217 Interactive Display Hook-Footnote-12664856
Node: PEP 208 New Coercion Model2664898
Ref: whatsnew/2 1 pep-208-new-coercion-model2665072
Ref: 15702665072
Ref: PEP 208 New Coercion Model-Footnote-12666689
Node: PEP 241 Metadata in Python Packages2666731
Ref: whatsnew/2 1 pep-241-metadata-in-python-packages2666900
Ref: 15712666900
Ref: PEP 241 Metadata in Python Packages-Footnote-12669017
Ref: PEP 241 Metadata in Python Packages-Footnote-22669099
Ref: PEP 241 Metadata in Python Packages-Footnote-32669141
Ref: PEP 241 Metadata in Python Packages-Footnote-42669183
Ref: PEP 241 Metadata in Python Packages-Footnote-52669225
Node: New and Improved Modules<4>2669267
Ref: whatsnew/2 1 new-and-improved-modules2669436
Ref: 15722669436
Node: Other Changes and Fixes<4>2675284
Ref: whatsnew/2 1 other-changes-and-fixes2675437
Ref: 15732675437
Node: Acknowledgements<7>2681392
Ref: whatsnew/2 1 acknowledgements2681509
Ref: 15772681509
Node: What’s New in Python 2 02681800
Ref: whatsnew/2 0 doc2681938
Ref: 15782681938
Ref: whatsnew/2 0 translation-repo2681938
Ref: 15792681938
Ref: whatsnew/2 0 what-s-new-in-python-2-02681938
Ref: 157a2681938
Node: Introduction<3>2682611
Ref: whatsnew/2 0 introduction2682720
Ref: 157b2682720
Node: What About Python 1 6?2683604
Ref: whatsnew/2 0 what-about-python-1-62683745
Ref: 157c2683745
Node: New Development Process2684986
Ref: whatsnew/2 0 new-development-process2685122
Ref: 157d2685122
Ref: New Development Process-Footnote-12690262
Ref: New Development Process-Footnote-22690304
Ref: New Development Process-Footnote-32690346
Node: Unicode<2>2690388
Ref: whatsnew/2 0 unicode2690521
Ref: 157e2690521
Ref: Unicode<2>-Footnote-12696691
Node: List Comprehensions2696733
Ref: whatsnew/2 0 list-comprehensions2696863
Ref: 157f2696863
Node: Augmented Assignment2700595
Ref: whatsnew/2 0 augmented-assignment2700729
Ref: 15802700729
Node: String Methods2702259
Ref: whatsnew/2 0 string-methods2702402
Ref: 15812702402
Node: Garbage Collection of Cycles2704255
Ref: whatsnew/2 0 garbage-collection-of-cycles2704396
Ref: 15822704396
Node: Other Core Changes2707743
Ref: whatsnew/2 0 other-core-changes2707884
Ref: 15832707884
Node: Minor Language Changes2708169
Ref: whatsnew/2 0 minor-language-changes2708284
Ref: 15842708284
Node: Changes to Built-in Functions2713345
Ref: whatsnew/2 0 changes-to-built-in-functions2713460
Ref: 15872713460
Node: Porting to 2 02715738
Ref: whatsnew/2 0 porting-to-2-02715878
Ref: 15882715878
Node: Extending/Embedding Changes2721194
Ref: whatsnew/2 0 extending-embedding-changes2721356
Ref: 158b2721356
Node: Distutils Making Modules Easy to Install2725208
Ref: whatsnew/2 0 distutils-making-modules-easy-to-install2725367
Ref: 15902725367
Node: XML Modules2728727
Ref: whatsnew/2 0 xml-modules2728873
Ref: 15912728873
Node: SAX2 Support2729772
Ref: whatsnew/2 0 sax2-support2729852
Ref: 15922729852
Node: DOM Support2731512
Ref: whatsnew/2 0 dom-support2731622
Ref: 15962731622
Node: Relationship to PyXML2734450
Ref: whatsnew/2 0 relationship-to-pyxml2734539
Ref: 15972734539
Node: Module changes2735823
Ref: whatsnew/2 0 module-changes2735940
Ref: 15982735940
Node: New modules2738417
Ref: whatsnew/2 0 new-modules2738540
Ref: 15992738540
Node: IDLE Improvements2742535
Ref: whatsnew/2 0 idle-improvements2742674
Ref: 159a2742674
Node: Deleted and Deprecated Modules2743809
Ref: whatsnew/2 0 deleted-and-deprecated-modules2743956
Ref: 159b2743956
Node: Acknowledgements<8>2744708
Ref: whatsnew/2 0 acknowledgements2744829
Ref: 159c2744829
Ref: Acknowledgements<8>-Footnote-12745428
Ref: Acknowledgements<8>-Footnote-22745468
Node: Changelog2745532
Ref: whatsnew/changelog doc2745635
Ref: 159d2745635
Ref: whatsnew/changelog changelog2745635
Ref: 13c2745635
Ref: whatsnew/changelog id12745635
Ref: 159e2745635
Ref: whatsnew/changelog translation-repo2745635
Ref: 159f2745635
Node: Python 3 13 13 final2751724
Ref: whatsnew/changelog python-3-13-13-final2751819
Ref: 15a02751819
Node: macOS2752038
Ref: whatsnew/changelog macos2752116
Ref: 15a12752116
Ref: macOS-Footnote-12752364
Ref: macOS-Footnote-22752420
Node: Windows2752476
Ref: whatsnew/changelog windows2752568
Ref: 15a22752568
Ref: Windows-Footnote-12752825
Ref: Windows-Footnote-22752881
Node: Tests2752937
Ref: whatsnew/changelog tests2753032
Ref: 15a32753032
Ref: Tests-Footnote-12753638
Ref: Tests-Footnote-22753694
Ref: Tests-Footnote-32753750
Node: Security2753806
Ref: whatsnew/changelog security2753901
Ref: 15a42753901
Ref: Security-Footnote-12754812
Ref: Security-Footnote-22754868
Ref: Security-Footnote-32754923
Ref: Security-Footnote-42754979
Ref: Security-Footnote-52755034
Ref: Security-Footnote-62755090
Ref: Security-Footnote-72755145
Ref: Security-Footnote-82755201
Node: Library2755257
Ref: whatsnew/changelog library2755363
Ref: 15a92755363
Ref: Library-Footnote-12764158
Ref: Library-Footnote-22764214
Ref: Library-Footnote-32764270
Ref: Library-Footnote-42764326
Ref: Library-Footnote-52764382
Ref: Library-Footnote-62764427
Ref: Library-Footnote-72764483
Ref: Library-Footnote-82764539
Ref: Library-Footnote-92764595
Ref: Library-Footnote-102764651
Ref: Library-Footnote-112764688
Ref: Library-Footnote-122764745
Ref: Library-Footnote-132764802
Ref: Library-Footnote-142764856
Ref: Library-Footnote-152764913
Ref: Library-Footnote-162764967
Ref: Library-Footnote-172765021
Ref: Library-Footnote-182765078
Ref: Library-Footnote-192765132
Ref: Library-Footnote-202765189
Ref: Library-Footnote-212765246
Ref: Library-Footnote-222765303
Ref: Library-Footnote-232765360
Ref: Library-Footnote-242765417
Ref: Library-Footnote-252765474
Ref: Library-Footnote-262765531
Ref: Library-Footnote-272765588
Ref: Library-Footnote-282765645
Ref: Library-Footnote-292765705
Ref: Library-Footnote-302765762
Ref: Library-Footnote-312765819
Ref: Library-Footnote-322765875
Ref: Library-Footnote-332765932
Ref: Library-Footnote-342765989
Ref: Library-Footnote-352766046
Ref: Library-Footnote-362766103
Ref: Library-Footnote-372766163
Ref: Library-Footnote-382766219
Ref: Library-Footnote-392766275
Ref: Library-Footnote-402766332
Ref: Library-Footnote-412766389
Ref: Library-Footnote-422766446
Ref: Library-Footnote-432766503
Ref: Library-Footnote-442766540
Ref: Library-Footnote-452766597
Ref: Library-Footnote-462766654
Ref: Library-Footnote-472766711
Ref: Library-Footnote-482766768
Ref: Library-Footnote-492766825
Ref: Library-Footnote-502766882
Ref: Library-Footnote-512766939
Ref: Library-Footnote-522766996
Ref: Library-Footnote-532767053
Ref: Library-Footnote-542767110
Ref: Library-Footnote-552767167
Ref: Library-Footnote-562767224
Ref: Library-Footnote-572767281
Ref: Library-Footnote-582767338
Ref: Library-Footnote-592767381
Ref: Library-Footnote-602767438
Ref: Library-Footnote-612767494
Node: Documentation<2>2767560
Ref: whatsnew/changelog documentation2767675
Ref: 15b82767675
Ref: Documentation<2>-Footnote-12768026
Ref: Documentation<2>-Footnote-22768082
Node: Core and Builtins2768138
Ref: whatsnew/changelog core-and-builtins2768251
Ref: 15b92768251
Ref: Core and Builtins-Footnote-12772505
Ref: Core and Builtins-Footnote-22772561
Ref: Core and Builtins-Footnote-32772614
Ref: Core and Builtins-Footnote-42772670
Ref: Core and Builtins-Footnote-52772726
Ref: Core and Builtins-Footnote-62772782
Ref: Core and Builtins-Footnote-72772838
Ref: Core and Builtins-Footnote-82772894
Ref: Core and Builtins-Footnote-92772950
Ref: Core and Builtins-Footnote-102773006
Ref: Core and Builtins-Footnote-112773063
Ref: Core and Builtins-Footnote-122773120
Ref: Core and Builtins-Footnote-132773177
Ref: Core and Builtins-Footnote-142773231
Ref: Core and Builtins-Footnote-152773288
Ref: Core and Builtins-Footnote-162773342
Ref: Core and Builtins-Footnote-172773399
Ref: Core and Builtins-Footnote-182773456
Ref: Core and Builtins-Footnote-192773513
Ref: Core and Builtins-Footnote-202773570
Ref: Core and Builtins-Footnote-212773627
Ref: Core and Builtins-Footnote-222773684
Ref: Core and Builtins-Footnote-232773741
Ref: Core and Builtins-Footnote-242773798
Ref: Core and Builtins-Footnote-252773855
Ref: Core and Builtins-Footnote-262773912
Ref: Core and Builtins-Footnote-272773969
Ref: Core and Builtins-Footnote-282774025
Ref: Core and Builtins-Footnote-292774082
Node: Build2774138
Ref: whatsnew/changelog build2774226
Ref: 15bc2774226
Ref: Build-Footnote-12775019
Ref: Build-Footnote-22775075
Ref: Build-Footnote-32775131
Ref: Build-Footnote-42775187
Node: Python 3 13 12 final2775243
Ref: whatsnew/changelog python-3-13-12-final2775367
Ref: 15bd2775367
Node: Windows<2>2775692
Ref: whatsnew/changelog id32775779
Ref: 15be2775779
Ref: Windows<2>-Footnote-12775982
Node: Tools/Demos2776038
Ref: whatsnew/changelog tools-demos2776142
Ref: 15bf2776142
Ref: Tools/Demos-Footnote-12776365
Node: Tests<2>2776421
Ref: whatsnew/changelog id42776526
Ref: 15c02776526
Ref: Tests<2>-Footnote-12777532
Ref: Tests<2>-Footnote-22777588
Ref: Tests<2>-Footnote-32777643
Ref: Tests<2>-Footnote-42777699
Ref: Tests<2>-Footnote-52777755
Ref: Tests<2>-Footnote-62777811
Node: Security<2>2777876
Ref: whatsnew/changelog id52777980
Ref: 15c22777980
Ref: Security<2>-Footnote-12779070
Ref: Security<2>-Footnote-22779126
Ref: Security<2>-Footnote-32779182
Ref: Security<2>-Footnote-42779238
Ref: Security<2>-Footnote-52779294
Ref: Security<2>-Footnote-62779350
Node: Library<2>2779406
Ref: whatsnew/changelog id62779509
Ref: 15c32779509
Ref: Library<2>-Footnote-12790029
Ref: Library<2>-Footnote-22790085
Ref: Library<2>-Footnote-32790141
Ref: Library<2>-Footnote-42790197
Ref: Library<2>-Footnote-52790253
Ref: Library<2>-Footnote-62790309
Ref: Library<2>-Footnote-72790365
Ref: Library<2>-Footnote-82790421
Ref: Library<2>-Footnote-92790477
Ref: Library<2>-Footnote-102790532
Ref: Library<2>-Footnote-112790589
Ref: Library<2>-Footnote-122790646
Ref: Library<2>-Footnote-132790703
Ref: Library<2>-Footnote-142790760
Ref: Library<2>-Footnote-152790817
Ref: Library<2>-Footnote-162790874
Ref: Library<2>-Footnote-172790931
Ref: Library<2>-Footnote-182790988
Ref: Library<2>-Footnote-192791045
Ref: Library<2>-Footnote-202791102
Ref: Library<2>-Footnote-212791159
Ref: Library<2>-Footnote-222791216
Ref: Library<2>-Footnote-232791273
Ref: Library<2>-Footnote-242791330
Ref: Library<2>-Footnote-252791387
Ref: Library<2>-Footnote-262791444
Ref: Library<2>-Footnote-272791501
Ref: Library<2>-Footnote-282791558
Ref: Library<2>-Footnote-292791615
Ref: Library<2>-Footnote-302791672
Ref: Library<2>-Footnote-312791729
Ref: Library<2>-Footnote-322791786
Ref: Library<2>-Footnote-332791843
Ref: Library<2>-Footnote-342791900
Ref: Library<2>-Footnote-352791957
Ref: Library<2>-Footnote-362792014
Ref: Library<2>-Footnote-372792071
Ref: Library<2>-Footnote-382792128
Ref: Library<2>-Footnote-392792185
Ref: Library<2>-Footnote-402792242
Ref: Library<2>-Footnote-412792299
Ref: Library<2>-Footnote-422792356
Ref: Library<2>-Footnote-432792413
Ref: Library<2>-Footnote-442792470
Ref: Library<2>-Footnote-452792527
Ref: Library<2>-Footnote-462792583
Ref: Library<2>-Footnote-472792639
Ref: Library<2>-Footnote-482792696
Ref: Library<2>-Footnote-492792753
Ref: Library<2>-Footnote-502792810
Ref: Library<2>-Footnote-512792867
Ref: Library<2>-Footnote-522792924
Ref: Library<2>-Footnote-532792980
Ref: Library<2>-Footnote-542793037
Ref: Library<2>-Footnote-552793093
Ref: Library<2>-Footnote-562793150
Ref: Library<2>-Footnote-572793207
Node: IDLE<3>2793264
Ref: whatsnew/changelog idle2793372
Ref: 15d62793372
Ref: IDLE<3>-Footnote-12793521
Node: Documentation<3>2793577
Ref: whatsnew/changelog id72793695
Ref: 15d72793695
Ref: Documentation<3>-Footnote-12793844
Node: Core and Builtins<2>2793900
Ref: whatsnew/changelog id82794016
Ref: 15d92794016
Ref: Core and Builtins<2>-Footnote-12798446
Ref: Core and Builtins<2>-Footnote-22798502
Ref: Core and Builtins<2>-Footnote-32798558
Ref: Core and Builtins<2>-Footnote-42798614
Ref: Core and Builtins<2>-Footnote-52798670
Ref: Core and Builtins<2>-Footnote-62798726
Ref: Core and Builtins<2>-Footnote-72798782
Ref: Core and Builtins<2>-Footnote-82798838
Ref: Core and Builtins<2>-Footnote-92798894
Ref: Core and Builtins<2>-Footnote-102798950
Ref: Core and Builtins<2>-Footnote-112799007
Ref: Core and Builtins<2>-Footnote-122799064
Ref: Core and Builtins<2>-Footnote-132799121
Ref: Core and Builtins<2>-Footnote-142799178
Ref: Core and Builtins<2>-Footnote-152799235
Ref: Core and Builtins<2>-Footnote-162799292
Ref: Core and Builtins<2>-Footnote-172799349
Ref: Core and Builtins<2>-Footnote-182799406
Ref: Core and Builtins<2>-Footnote-192799463
Ref: Core and Builtins<2>-Footnote-202799520
Ref: Core and Builtins<2>-Footnote-212799577
Ref: Core and Builtins<2>-Footnote-222799634
Ref: Core and Builtins<2>-Footnote-232799691
Ref: Core and Builtins<2>-Footnote-242799748
Ref: Core and Builtins<2>-Footnote-252799805
Node: C API2799862
Ref: whatsnew/changelog c-api2799970
Ref: 15e72799970
Ref: C API-Footnote-12800157
Node: Build<2>2800213
Ref: whatsnew/changelog id92800292
Ref: 15e82800292
Ref: Build<2>-Footnote-12801021
Ref: Build<2>-Footnote-22801077
Ref: Build<2>-Footnote-32801133
Node: Python 3 13 11 final2801189
Ref: whatsnew/changelog python-3-13-11-final2801313
Ref: 15e92801313
Node: Security<3>2801499
Ref: whatsnew/changelog id102801586
Ref: 15ea2801586
Ref: Security<3>-Footnote-12802545
Ref: Security<3>-Footnote-22802601
Ref: Security<3>-Footnote-32802657
Node: Library<3>2802713
Ref: whatsnew/changelog id112802829
Ref: 15eb2802829
Ref: Library<3>-Footnote-12803615
Ref: Library<3>-Footnote-22803671
Node: Core and Builtins<3>2803727
Ref: whatsnew/changelog id122803823
Ref: 15ec2803823
Ref: Core and Builtins<3>-Footnote-12804060
Node: Python 3 13 10 final2804116
Ref: whatsnew/changelog python-3-13-10-final2804239
Ref: 15ed2804239
Node: Tools/Demos<2>2804546
Ref: whatsnew/changelog id132804634
Ref: 15ee2804634
Ref: Tools/Demos<2>-Footnote-12804812
Node: Tests<3>2804868
Ref: whatsnew/changelog id142804976
Ref: 15ef2804976
Ref: Tests<3>-Footnote-12805494
Ref: Tests<3>-Footnote-22805550
Ref: Tests<3>-Footnote-32805606
Node: Security<4>2805662
Ref: whatsnew/changelog id152805766
Ref: 15f02805766
Ref: Security<4>-Footnote-12806890
Ref: Security<4>-Footnote-22806946
Ref: Security<4>-Footnote-32807002
Ref: Security<4>-Footnote-42807058
Ref: Security<4>-Footnote-52807114
Node: Library<4>2807170
Ref: whatsnew/changelog id162807273
Ref: 15f12807273
Ref: Library<4>-Footnote-12816709
Ref: Library<4>-Footnote-22816764
Ref: Library<4>-Footnote-32816819
Ref: Library<4>-Footnote-42816875
Ref: Library<4>-Footnote-52816930
Ref: Library<4>-Footnote-62816986
Ref: Library<4>-Footnote-72817042
Ref: Library<4>-Footnote-82817098
Ref: Library<4>-Footnote-92817154
Ref: Library<4>-Footnote-102817210
Ref: Library<4>-Footnote-112817267
Ref: Library<4>-Footnote-122817324
Ref: Library<4>-Footnote-132817381
Ref: Library<4>-Footnote-142817438
Ref: Library<4>-Footnote-152817495
Ref: Library<4>-Footnote-162817552
Ref: Library<4>-Footnote-172817609
Ref: Library<4>-Footnote-182817666
Ref: Library<4>-Footnote-192817723
Ref: Library<4>-Footnote-202817780
Ref: Library<4>-Footnote-212817837
Ref: Library<4>-Footnote-222817894
Ref: Library<4>-Footnote-232817951
Ref: Library<4>-Footnote-242818008
Ref: Library<4>-Footnote-252818065
Ref: Library<4>-Footnote-262818122
Ref: Library<4>-Footnote-272818179
Ref: Library<4>-Footnote-282818236
Ref: Library<4>-Footnote-292818293
Ref: Library<4>-Footnote-302818350
Ref: Library<4>-Footnote-312818407
Ref: Library<4>-Footnote-322818464
Ref: Library<4>-Footnote-332818521
Ref: Library<4>-Footnote-342818578
Ref: Library<4>-Footnote-352818635
Ref: Library<4>-Footnote-362818691
Ref: Library<4>-Footnote-372818748
Ref: Library<4>-Footnote-382818788
Ref: Library<4>-Footnote-392818830
Ref: Library<4>-Footnote-402818887
Ref: Library<4>-Footnote-412818944
Ref: Library<4>-Footnote-422819000
Ref: Library<4>-Footnote-432819057
Ref: Library<4>-Footnote-442819114
Ref: Library<4>-Footnote-452819171
Ref: Library<4>-Footnote-462819228
Ref: Library<4>-Footnote-472819284
Ref: Library<4>-Footnote-482819340
Ref: Library<4>-Footnote-492819396
Ref: Library<4>-Footnote-502819452
Ref: Library<4>-Footnote-512819509
Ref: Library<4>-Footnote-522819566
Ref: Library<4>-Footnote-532819623
Ref: Library<4>-Footnote-542819680
Node: IDLE<4>2819737
Ref: whatsnew/changelog id172819845
Ref: 16022819845
Ref: IDLE<4>-Footnote-12820009
Node: Documentation<4>2820064
Ref: whatsnew/changelog id182820182
Ref: 16032820182
Ref: Documentation<4>-Footnote-12820665
Ref: Documentation<4>-Footnote-22820721
Ref: Documentation<4>-Footnote-32820786
Node: Core and Builtins<4>2820842
Ref: whatsnew/changelog id192820961
Ref: 16052820961
Ref: Core and Builtins<4>-Footnote-12824197
Ref: Core and Builtins<4>-Footnote-22824253
Ref: Core and Builtins<4>-Footnote-32824309
Ref: Core and Builtins<4>-Footnote-42824365
Ref: Core and Builtins<4>-Footnote-52824421
Ref: Core and Builtins<4>-Footnote-62824477
Ref: Core and Builtins<4>-Footnote-72824533
Ref: Core and Builtins<4>-Footnote-82824589
Ref: Core and Builtins<4>-Footnote-92824645
Ref: Core and Builtins<4>-Footnote-102824701
Ref: Core and Builtins<4>-Footnote-112824758
Ref: Core and Builtins<4>-Footnote-122824815
Ref: Core and Builtins<4>-Footnote-132824872
Ref: Core and Builtins<4>-Footnote-142824929
Ref: Core and Builtins<4>-Footnote-152824986
Ref: Core and Builtins<4>-Footnote-162825043
Ref: Core and Builtins<4>-Footnote-172825100
Ref: Core and Builtins<4>-Footnote-182825157
Ref: Core and Builtins<4>-Footnote-192825214
Node: C API<2>2825271
Ref: whatsnew/changelog id202825365
Ref: 16072825365
Ref: C API<2>-Footnote-12825767
Ref: C API<2>-Footnote-22825823
Node: Python 3 13 9 final2825879
Ref: whatsnew/changelog python-3-13-9-final2826001
Ref: 16092826001
Node: Library<5>2826117
Ref: whatsnew/changelog id212826183
Ref: 160a2826183
Ref: Library<5>-Footnote-12826394
Node: Python 3 13 8 final2826450
Ref: whatsnew/changelog python-3-13-8-final2826571
Ref: 160b2826571
Node: macOS<2>2826885
Ref: whatsnew/changelog id222826968
Ref: 160c2826968
Ref: macOS<2>-Footnote-12827166
Ref: macOS<2>-Footnote-22827222
Node: Windows<3>2827278
Ref: whatsnew/changelog id232827384
Ref: 160d2827384
Ref: Windows<3>-Footnote-12827609
Ref: Windows<3>-Footnote-22827665
Node: Tools/Demos<3>2827721
Ref: whatsnew/changelog id242827827
Ref: 160e2827827
Ref: Tools/Demos<3>-Footnote-12828319
Ref: Tools/Demos<3>-Footnote-22828375
Node: Tests<4>2828431
Ref: whatsnew/changelog id252828538
Ref: 160f2828538
Ref: Tests<4>-Footnote-12828747
Node: Security<5>2828803
Ref: whatsnew/changelog id262828906
Ref: 16102828906
Ref: Security<5>-Footnote-12829872
Ref: Security<5>-Footnote-22829928
Ref: Security<5>-Footnote-32829984
Node: Library<6>2830040
Ref: whatsnew/changelog id272830155
Ref: 16132830155
Ref: Library<6>-Footnote-12835871
Ref: Library<6>-Footnote-22835927
Ref: Library<6>-Footnote-32835983
Ref: Library<6>-Footnote-42836039
Ref: Library<6>-Footnote-52836095
Ref: Library<6>-Footnote-62836151
Ref: Library<6>-Footnote-72836207
Ref: Library<6>-Footnote-82836263
Ref: Library<6>-Footnote-92836319
Ref: Library<6>-Footnote-102836375
Ref: Library<6>-Footnote-112836432
Ref: Library<6>-Footnote-122836488
Ref: Library<6>-Footnote-132836545
Ref: Library<6>-Footnote-142836602
Ref: Library<6>-Footnote-152836659
Ref: Library<6>-Footnote-162836716
Ref: Library<6>-Footnote-172836772
Ref: Library<6>-Footnote-182836829
Ref: Library<6>-Footnote-192836886
Ref: Library<6>-Footnote-202836943
Ref: Library<6>-Footnote-212837000
Ref: Library<6>-Footnote-222837057
Ref: Library<6>-Footnote-232837114
Ref: Library<6>-Footnote-242837171
Ref: Library<6>-Footnote-252837228
Ref: Library<6>-Footnote-262837285
Ref: Library<6>-Footnote-272837342
Ref: Library<6>-Footnote-282837399
Ref: Library<6>-Footnote-292837456
Ref: Library<6>-Footnote-302837513
Ref: Library<6>-Footnote-312837570
Ref: Library<6>-Footnote-322837627
Ref: Library<6>-Footnote-332837683
Ref: Library<6>-Footnote-342837749
Node: Core and Builtins<5>2837815
Ref: whatsnew/changelog id282837927
Ref: 161c2837927
Ref: Core and Builtins<5>-Footnote-12839023
Ref: Core and Builtins<5>-Footnote-22839079
Ref: Core and Builtins<5>-Footnote-32839134
Ref: Core and Builtins<5>-Footnote-42839190
Ref: Core and Builtins<5>-Footnote-52839246
Ref: Core and Builtins<5>-Footnote-62839302
Ref: Core and Builtins<5>-Footnote-72839358
Node: C API<3>2839414
Ref: whatsnew/changelog id292839524
Ref: 161f2839524
Ref: C API<3>-Footnote-12840772
Node: Build<3>2840827
Ref: whatsnew/changelog id302840908
Ref: 16202840908
Ref: Build<3>-Footnote-12841283
Node: Python 3 13 7 final2841339
Ref: whatsnew/changelog python-3-13-7-final2841460
Ref: 16212841460
Node: Library<7>2841654
Ref: whatsnew/changelog id312841745
Ref: 16222841745
Ref: Library<7>-Footnote-12842653
Ref: Library<7>-Footnote-22842709
Ref: Library<7>-Footnote-32842765
Ref: Library<7>-Footnote-42842821
Node: Documentation<5>2842877
Ref: whatsnew/changelog id322842997
Ref: 16282842997
Ref: Documentation<5>-Footnote-12843164
Node: Core and Builtins<6>2843220
Ref: whatsnew/changelog id332843321
Ref: 16292843321
Ref: Core and Builtins<6>-Footnote-12843779
Node: Python 3 13 6 final2843835
Ref: whatsnew/changelog python-3-13-6-final2843956
Ref: 162a2843956
Node: macOS<3>2844286
Ref: whatsnew/changelog id342844369
Ref: 162b2844369
Ref: macOS<3>-Footnote-12844759
Ref: macOS<3>-Footnote-22844815
Node: Windows<4>2844871
Ref: whatsnew/changelog id352844977
Ref: 162c2844977
Ref: Windows<4>-Footnote-12845121
Node: Tools/Demos<4>2845177
Ref: whatsnew/changelog id362845283
Ref: 162d2845283
Ref: Tools/Demos<4>-Footnote-12845453
Node: Tests<5>2845509
Ref: whatsnew/changelog id372845616
Ref: 162e2845616
Ref: Tests<5>-Footnote-12846021
Ref: Tests<5>-Footnote-22846077
Ref: Tests<5>-Footnote-32846133
Node: Security<6>2846189
Ref: whatsnew/changelog id382846292
Ref: 162f2846292
Ref: Security<6>-Footnote-12848140
Ref: Security<6>-Footnote-22848196
Ref: Security<6>-Footnote-32848252
Ref: Security<6>-Footnote-42848308
Node: Library<8>2848364
Ref: whatsnew/changelog id392848475
Ref: 16302848475
Ref: Library<8>-Footnote-12855185
Ref: Library<8>-Footnote-22855241
Ref: Library<8>-Footnote-32855297
Ref: Library<8>-Footnote-42855353
Ref: Library<8>-Footnote-52855408
Ref: Library<8>-Footnote-62855463
Ref: Library<8>-Footnote-72855519
Ref: Library<8>-Footnote-82855575
Ref: Library<8>-Footnote-92855631
Ref: Library<8>-Footnote-102855687
Ref: Library<8>-Footnote-112855744
Ref: Library<8>-Footnote-122855800
Ref: Library<8>-Footnote-132855856
Ref: Library<8>-Footnote-142855913
Ref: Library<8>-Footnote-152855970
Ref: Library<8>-Footnote-162856027
Ref: Library<8>-Footnote-172856083
Ref: Library<8>-Footnote-182856139
Ref: Library<8>-Footnote-192856196
Ref: Library<8>-Footnote-202856253
Ref: Library<8>-Footnote-212856310
Ref: Library<8>-Footnote-222856367
Ref: Library<8>-Footnote-232856424
Ref: Library<8>-Footnote-242856481
Ref: Library<8>-Footnote-252856538
Ref: Library<8>-Footnote-262856595
Ref: Library<8>-Footnote-272856652
Ref: Library<8>-Footnote-282856709
Ref: Library<8>-Footnote-292856766
Ref: Library<8>-Footnote-302856842
Ref: Library<8>-Footnote-312856899
Ref: Library<8>-Footnote-322856956
Ref: Library<8>-Footnote-332857013
Ref: Library<8>-Footnote-342857070
Ref: Library<8>-Footnote-352857127
Ref: Library<8>-Footnote-362857184
Ref: Library<8>-Footnote-372857240
Node: Documentation<6>2857297
Ref: whatsnew/changelog id402857417
Ref: 16352857417
Ref: Documentation<6>-Footnote-12857655
Node: Core and Builtins<7>2857711
Ref: whatsnew/changelog id412857829
Ref: 16362857829
Ref: Core and Builtins<7>-Footnote-12860657
Ref: Core and Builtins<7>-Footnote-22860712
Ref: Core and Builtins<7>-Footnote-32860768
Ref: Core and Builtins<7>-Footnote-42860824
Ref: Core and Builtins<7>-Footnote-52860880
Ref: Core and Builtins<7>-Footnote-62860935
Ref: Core and Builtins<7>-Footnote-72860991
Ref: Core and Builtins<7>-Footnote-82861047
Ref: Core and Builtins<7>-Footnote-92861103
Ref: Core and Builtins<7>-Footnote-102861159
Ref: Core and Builtins<7>-Footnote-112861216
Ref: Core and Builtins<7>-Footnote-122861273
Ref: Core and Builtins<7>-Footnote-132861330
Ref: Core and Builtins<7>-Footnote-142861386
Ref: Core and Builtins<7>-Footnote-152861443
Node: Build<4>2861500
Ref: whatsnew/changelog id422861593
Ref: 16372861593
Ref: Build<4>-Footnote-12861757
Node: Python 3 13 5 final2861813
Ref: whatsnew/changelog python-3-13-5-final2861934
Ref: 16382861934
Node: Windows<5>2862154
Ref: whatsnew/changelog id432862237
Ref: 16392862237
Ref: Windows<5>-Footnote-12862522
Node: Tests<6>2862578
Ref: whatsnew/changelog id442862680
Ref: 163a2862680
Ref: Tests<6>-Footnote-12862802
Node: Library<9>2862858
Ref: whatsnew/changelog id452862970
Ref: 163b2862970
Ref: Library<9>-Footnote-12864182
Ref: Library<9>-Footnote-22864238
Ref: Library<9>-Footnote-32864294
Ref: Library<9>-Footnote-42864350
Ref: Library<9>-Footnote-52864406
Ref: Library<9>-Footnote-62864462
Ref: Library<9>-Footnote-72864521
Ref: Library<9>-Footnote-82864577
Ref: Library<9>-Footnote-92864633
Node: Core and Builtins<8>2864689
Ref: whatsnew/changelog id462864801
Ref: 163d2864801
Ref: Core and Builtins<8>-Footnote-12865112
Ref: Core and Builtins<8>-Footnote-22865168
Node: C API<4>2865224
Ref: whatsnew/changelog id472865317
Ref: 163e2865317
Ref: C API<4>-Footnote-12865824
Ref: C API<4>-Footnote-22865880
Node: Python 3 13 4 final2865936
Ref: whatsnew/changelog python-3-13-4-final2866057
Ref: 16412866057
Node: Windows<6>2866468
Ref: whatsnew/changelog id482866551
Ref: 16422866551
Ref: Windows<6>-Footnote-12867150
Ref: Windows<6>-Footnote-22867206
Ref: Windows<6>-Footnote-32867261
Ref: Windows<6>-Footnote-42867317
Node: Tests<7>2867373
Ref: whatsnew/changelog id492867476
Ref: 16432867476
Ref: Tests<7>-Footnote-12868274
Ref: Tests<7>-Footnote-22868330
Ref: Tests<7>-Footnote-32868386
Ref: Tests<7>-Footnote-42868442
Node: Security<7>2868498
Ref: whatsnew/changelog id502868602
Ref: 16442868602
Ref: Security<7>-Footnote-12869274
Ref: Security<7>-Footnote-22869330
Ref: Security<7>-Footnote-32869386
Ref: Security<7>-Footnote-42869441
Ref: Security<7>-Footnote-52869496
Ref: Security<7>-Footnote-62869551
Ref: Security<7>-Footnote-72869607
Node: Library<10>2869663
Ref: whatsnew/changelog id512869766
Ref: 16452869766
Ref: Library<10>-Footnote-12879171
Ref: Library<10>-Footnote-22879227
Ref: Library<10>-Footnote-32879283
Ref: Library<10>-Footnote-42879339
Ref: Library<10>-Footnote-52879395
Ref: Library<10>-Footnote-62879450
Ref: Library<10>-Footnote-72879506
Ref: Library<10>-Footnote-82879562
Ref: Library<10>-Footnote-92879617
Ref: Library<10>-Footnote-102879673
Ref: Library<10>-Footnote-112879730
Ref: Library<10>-Footnote-122879787
Ref: Library<10>-Footnote-132879844
Ref: Library<10>-Footnote-142879901
Ref: Library<10>-Footnote-152879958
Ref: Library<10>-Footnote-162880015
Ref: Library<10>-Footnote-172880071
Ref: Library<10>-Footnote-182880127
Ref: Library<10>-Footnote-192880184
Ref: Library<10>-Footnote-202880241
Ref: Library<10>-Footnote-212880298
Ref: Library<10>-Footnote-222880355
Ref: Library<10>-Footnote-232880412
Ref: Library<10>-Footnote-242880469
Ref: Library<10>-Footnote-252880526
Ref: Library<10>-Footnote-262880583
Ref: Library<10>-Footnote-272880640
Ref: Library<10>-Footnote-282880697
Ref: Library<10>-Footnote-292880754
Ref: Library<10>-Footnote-302880811
Ref: Library<10>-Footnote-312880868
Ref: Library<10>-Footnote-322880925
Ref: Library<10>-Footnote-332880982
Ref: Library<10>-Footnote-342881039
Ref: Library<10>-Footnote-352881096
Ref: Library<10>-Footnote-362881153
Ref: Library<10>-Footnote-372881209
Ref: Library<10>-Footnote-382881266
Ref: Library<10>-Footnote-392881323
Ref: Library<10>-Footnote-402881380
Ref: Library<10>-Footnote-412881437
Ref: Library<10>-Footnote-422881494
Ref: Library<10>-Footnote-432881551
Ref: Library<10>-Footnote-442881608
Ref: Library<10>-Footnote-452881665
Ref: Library<10>-Footnote-462881722
Ref: Library<10>-Footnote-472881779
Ref: Library<10>-Footnote-482881835
Ref: Library<10>-Footnote-492881891
Node: IDLE<5>2881957
Ref: whatsnew/changelog id522882065
Ref: 164e2882065
Ref: IDLE<5>-Footnote-12882205
Node: Documentation<7>2882261
Ref: whatsnew/changelog id532882369
Ref: 164f2882369
Ref: Documentation<7>-Footnote-12882589
Node: Library<11>2882645
Ref: whatsnew/changelog id542882766
Ref: 16512882766
Ref: Library<11>-Footnote-12882956
Node: Core and Builtins<9>2883012
Ref: whatsnew/changelog id552883128
Ref: 16522883128
Ref: Core and Builtins<9>-Footnote-12883398
Node: Library<12>2883454
Ref: whatsnew/changelog id562883580
Ref: 16532883580
Ref: Library<12>-Footnote-12883797
Node: Core and Builtins<10>2883853
Ref: whatsnew/changelog id572883967
Ref: 16542883967
Ref: Core and Builtins<10>-Footnote-12887193
Ref: Core and Builtins<10>-Footnote-22887249
Ref: Core and Builtins<10>-Footnote-32887305
Ref: Core and Builtins<10>-Footnote-42887361
Ref: Core and Builtins<10>-Footnote-52887417
Ref: Core and Builtins<10>-Footnote-62887473
Ref: Core and Builtins<10>-Footnote-72887529
Ref: Core and Builtins<10>-Footnote-82887585
Ref: Core and Builtins<10>-Footnote-92887641
Ref: Core and Builtins<10>-Footnote-102887697
Ref: Core and Builtins<10>-Footnote-112887754
Ref: Core and Builtins<10>-Footnote-122887811
Ref: Core and Builtins<10>-Footnote-132887868
Ref: Core and Builtins<10>-Footnote-142887913
Ref: Core and Builtins<10>-Footnote-152887970
Ref: Core and Builtins<10>-Footnote-162888027
Ref: Core and Builtins<10>-Footnote-172888084
Ref: Core and Builtins<10>-Footnote-182888141
Ref: Core and Builtins<10>-Footnote-192888198
Ref: Core and Builtins<10>-Footnote-202888255
Ref: Core and Builtins<10>-Footnote-212888312
Node: C API<5>2888369
Ref: whatsnew/changelog id582888480
Ref: 16582888480
Ref: C API<5>-Footnote-12888690
Node: Build<5>2888746
Ref: whatsnew/changelog id592888827
Ref: 165a2888827
Ref: Build<5>-Footnote-12889673
Ref: Build<5>-Footnote-22889729
Ref: Build<5>-Footnote-32889785
Ref: Build<5>-Footnote-42889841
Ref: Build<5>-Footnote-52889897
Ref: Build<5>-Footnote-62889953
Node: Python 3 13 3 final2890009
Ref: whatsnew/changelog python-3-13-3-final2890130
Ref: 165b2890130
Node: macOS<4>2890568
Ref: whatsnew/changelog id602890651
Ref: 165c2890651
Ref: macOS<4>-Footnote-12891016
Ref: macOS<4>-Footnote-22891072
Ref: macOS<4>-Footnote-32891128
Ref: macOS<4>-Footnote-42891184
Node: Windows<7>2891239
Ref: whatsnew/changelog id612891345
Ref: 165d2891345
Ref: Windows<7>-Footnote-12891794
Ref: Windows<7>-Footnote-22891850
Ref: Windows<7>-Footnote-32891906
Ref: Windows<7>-Footnote-42891962
Node: Tools/Demos<5>2892029
Ref: whatsnew/changelog id622892135
Ref: 165e2892135
Ref: Tools/Demos<5>-Footnote-12892569
Ref: Tools/Demos<5>-Footnote-22892625
Ref: Tools/Demos<5>-Footnote-32892680
Node: Tests<8>2892736
Ref: whatsnew/changelog id632892843
Ref: 165f2892843
Ref: Tests<8>-Footnote-12893581
Ref: Tests<8>-Footnote-22893637
Ref: Tests<8>-Footnote-32893693
Ref: Tests<8>-Footnote-42893749
Ref: Tests<8>-Footnote-52893805
Node: Security<8>2893861
Ref: whatsnew/changelog id642893965
Ref: 16602893965
Ref: Security<8>-Footnote-12894930
Ref: Security<8>-Footnote-22894986
Ref: Security<8>-Footnote-32895042
Ref: Security<8>-Footnote-42895098
Node: Library<13>2895154
Ref: whatsnew/changelog id652895257
Ref: 16612895257
Ref: Library<13>-Footnote-12902671
Ref: Library<13>-Footnote-22902727
Ref: Library<13>-Footnote-32902783
Ref: Library<13>-Footnote-42902839
Ref: Library<13>-Footnote-52902895
Ref: Library<13>-Footnote-62902951
Ref: Library<13>-Footnote-72903007
Ref: Library<13>-Footnote-82903063
Ref: Library<13>-Footnote-92903119
Ref: Library<13>-Footnote-102903175
Ref: Library<13>-Footnote-112903232
Ref: Library<13>-Footnote-122903289
Ref: Library<13>-Footnote-132903346
Ref: Library<13>-Footnote-142903403
Ref: Library<13>-Footnote-152903460
Ref: Library<13>-Footnote-162903517
Ref: Library<13>-Footnote-172903574
Ref: Library<13>-Footnote-182903631
Ref: Library<13>-Footnote-192903688
Ref: Library<13>-Footnote-202903745
Ref: Library<13>-Footnote-212903802
Ref: Library<13>-Footnote-222903859
Ref: Library<13>-Footnote-232903916
Ref: Library<13>-Footnote-242903973
Ref: Library<13>-Footnote-252904030
Ref: Library<13>-Footnote-262904087
Ref: Library<13>-Footnote-272904144
Ref: Library<13>-Footnote-282904200
Ref: Library<13>-Footnote-292904257
Ref: Library<13>-Footnote-302904313
Ref: Library<13>-Footnote-312904370
Ref: Library<13>-Footnote-322904427
Ref: Library<13>-Footnote-332904484
Ref: Library<13>-Footnote-342904541
Ref: Library<13>-Footnote-352904598
Ref: Library<13>-Footnote-362904654
Ref: Library<13>-Footnote-372904711
Ref: Library<13>-Footnote-382904768
Ref: Library<13>-Footnote-392904825
Ref: Library<13>-Footnote-402904882
Ref: Library<13>-Footnote-412904939
Ref: Library<13>-Footnote-422904996
Ref: Library<13>-Footnote-432905053
Ref: Library<13>-Footnote-442905110
Node: IDLE<6>2905167
Ref: whatsnew/changelog id662905275
Ref: 16712905275
Ref: IDLE<6>-Footnote-12905497
Node: Documentation<8>2905553
Ref: whatsnew/changelog id672905671
Ref: 16722905671
Ref: Documentation<8>-Footnote-12906240
Ref: Documentation<8>-Footnote-22906296
Ref: Documentation<8>-Footnote-32906352
Ref: Documentation<8>-Footnote-42906408
Node: Core and Builtins<11>2906463
Ref: whatsnew/changelog id682906585
Ref: 16762906585
Ref: Core and Builtins<11>-Footnote-12909056
Ref: Core and Builtins<11>-Footnote-22909112
Ref: Core and Builtins<11>-Footnote-32909168
Ref: Core and Builtins<11>-Footnote-42909224
Ref: Core and Builtins<11>-Footnote-52909280
Ref: Core and Builtins<11>-Footnote-62909336
Ref: Core and Builtins<11>-Footnote-72909392
Ref: Core and Builtins<11>-Footnote-82909448
Ref: Core and Builtins<11>-Footnote-92909504
Ref: Core and Builtins<11>-Footnote-102909560
Ref: Core and Builtins<11>-Footnote-112909617
Ref: Core and Builtins<11>-Footnote-122909674
Ref: Core and Builtins<11>-Footnote-132909731
Ref: Core and Builtins<11>-Footnote-142909788
Ref: Core and Builtins<11>-Footnote-152909844
Ref: Core and Builtins<11>-Footnote-162909901
Ref: Core and Builtins<11>-Footnote-172909958
Node: Library<14>2910015
Ref: whatsnew/changelog id692910142
Ref: 167a2910142
Ref: Library<14>-Footnote-12910287
Node: Core and Builtins<12>2910343
Ref: whatsnew/changelog id702910457
Ref: 167b2910457
Ref: Core and Builtins<12>-Footnote-12912188
Ref: Core and Builtins<12>-Footnote-22912244
Ref: Core and Builtins<12>-Footnote-32912300
Ref: Core and Builtins<12>-Footnote-42912356
Ref: Core and Builtins<12>-Footnote-52912412
Ref: Core and Builtins<12>-Footnote-62912468
Ref: Core and Builtins<12>-Footnote-72912524
Ref: Core and Builtins<12>-Footnote-82912580
Ref: Core and Builtins<12>-Footnote-92912636
Ref: Core and Builtins<12>-Footnote-102912692
Node: C API<6>2912749
Ref: whatsnew/changelog id712912860
Ref: 167e2912860
Ref: C API<6>-Footnote-12913225
Ref: C API<6>-Footnote-22913281
Node: Build<6>2913337
Ref: whatsnew/changelog id722913418
Ref: 167f2913418
Ref: Build<6>-Footnote-12914306
Ref: Build<6>-Footnote-22914362
Ref: Build<6>-Footnote-32914418
Ref: Build<6>-Footnote-42914474
Ref: Build<6>-Footnote-52914530
Ref: Build<6>-Footnote-62914586
Node: Python 3 13 2 final2914642
Ref: whatsnew/changelog python-3-13-2-final2914763
Ref: 16802914763
Node: macOS<5>2915140
Ref: whatsnew/changelog id732915223
Ref: 16812915223
Ref: macOS<5>-Footnote-12915427
Node: Windows<8>2915483
Ref: whatsnew/changelog id742915589
Ref: 16822915589
Ref: Windows<8>-Footnote-12915781
Node: Tools/Demos<6>2915837
Ref: whatsnew/changelog id752915943
Ref: 16832915943
Ref: Tools/Demos<6>-Footnote-12916309
Ref: Tools/Demos<6>-Footnote-22916365
Node: Tests<9>2916421
Ref: whatsnew/changelog id762916528
Ref: 16842916528
Ref: Tests<9>-Footnote-12916929
Ref: Tests<9>-Footnote-22916985
Ref: Tests<9>-Footnote-32917041
Node: Security<9>2917097
Ref: whatsnew/changelog id772917201
Ref: 16852917201
Ref: Security<9>-Footnote-12919013
Ref: Security<9>-Footnote-22919069
Ref: Security<9>-Footnote-32919130
Ref: Security<9>-Footnote-42919186
Ref: Security<9>-Footnote-52919242
Ref: Security<9>-Footnote-62919297
Node: Library<15>2919353
Ref: whatsnew/changelog id782919465
Ref: 16862919465
Ref: Library<15>-Footnote-12928247
Ref: Library<15>-Footnote-22928303
Ref: Library<15>-Footnote-32928359
Ref: Library<15>-Footnote-42928415
Ref: Library<15>-Footnote-52928471
Ref: Library<15>-Footnote-62928527
Ref: Library<15>-Footnote-72928583
Ref: Library<15>-Footnote-82928639
Ref: Library<15>-Footnote-92928695
Ref: Library<15>-Footnote-102928751
Ref: Library<15>-Footnote-112928808
Ref: Library<15>-Footnote-122928865
Ref: Library<15>-Footnote-132928922
Ref: Library<15>-Footnote-142928979
Ref: Library<15>-Footnote-152929036
Ref: Library<15>-Footnote-162929093
Ref: Library<15>-Footnote-172929150
Ref: Library<15>-Footnote-182929207
Ref: Library<15>-Footnote-192929264
Ref: Library<15>-Footnote-202929321
Ref: Library<15>-Footnote-212929377
Ref: Library<15>-Footnote-222929434
Ref: Library<15>-Footnote-232929491
Ref: Library<15>-Footnote-242929548
Ref: Library<15>-Footnote-252929604
Ref: Library<15>-Footnote-262929661
Ref: Library<15>-Footnote-272929718
Ref: Library<15>-Footnote-282929775
Ref: Library<15>-Footnote-292929832
Ref: Library<15>-Footnote-302929889
Ref: Library<15>-Footnote-312929946
Ref: Library<15>-Footnote-322930002
Ref: Library<15>-Footnote-332930059
Ref: Library<15>-Footnote-342930116
Ref: Library<15>-Footnote-352930164
Ref: Library<15>-Footnote-362930209
Ref: Library<15>-Footnote-372930266
Ref: Library<15>-Footnote-382930323
Ref: Library<15>-Footnote-392930380
Ref: Library<15>-Footnote-402930437
Ref: Library<15>-Footnote-412930494
Ref: Library<15>-Footnote-422930550
Ref: Library<15>-Footnote-432930606
Ref: Library<15>-Footnote-442930663
Ref: Library<15>-Footnote-452930719
Ref: Library<15>-Footnote-462930776
Ref: Library<15>-Footnote-472930833
Ref: Library<15>-Footnote-482930890
Ref: Library<15>-Footnote-492930947
Ref: Library<15>-Footnote-502931004
Ref: Library<15>-Footnote-512931061
Ref: Library<15>-Footnote-522931118
Ref: Library<15>-Footnote-532931175
Ref: Library<15>-Footnote-542931232
Ref: Library<15>-Footnote-552931291
Ref: Library<15>-Footnote-562931351
Ref: Library<15>-Footnote-572931408
Node: Documentation<9>2931465
Ref: whatsnew/changelog id792931577
Ref: 168b2931577
Ref: Documentation<9>-Footnote-12932001
Ref: Documentation<9>-Footnote-22932057
Node: Library<16>2932112
Ref: whatsnew/changelog id802932234
Ref: 168d2932234
Ref: Library<16>-Footnote-12932433
Node: Core and Builtins<13>2932489
Ref: whatsnew/changelog id812932603
Ref: 168e2932603
Ref: Core and Builtins<13>-Footnote-12935292
Ref: Core and Builtins<13>-Footnote-22935348
Ref: Core and Builtins<13>-Footnote-32935404
Ref: Core and Builtins<13>-Footnote-42935460
Ref: Core and Builtins<13>-Footnote-52935516
Ref: Core and Builtins<13>-Footnote-62935572
Ref: Core and Builtins<13>-Footnote-72935628
Ref: Core and Builtins<13>-Footnote-82935684
Ref: Core and Builtins<13>-Footnote-92935740
Ref: Core and Builtins<13>-Footnote-102935796
Ref: Core and Builtins<13>-Footnote-112935853
Ref: Core and Builtins<13>-Footnote-122935910
Ref: Core and Builtins<13>-Footnote-132935967
Ref: Core and Builtins<13>-Footnote-142936024
Ref: Core and Builtins<13>-Footnote-152936081
Ref: Core and Builtins<13>-Footnote-162936138
Ref: Core and Builtins<13>-Footnote-172936195
Node: C API<7>2936252
Ref: whatsnew/changelog id822936363
Ref: 16902936363
Ref: C API<7>-Footnote-12936542
Node: Build<7>2936598
Ref: whatsnew/changelog id832936679
Ref: 16922936679
Ref: Build<7>-Footnote-12937452
Ref: Build<7>-Footnote-22937508
Ref: Build<7>-Footnote-32937564
Ref: Build<7>-Footnote-42937620
Ref: Build<7>-Footnote-52937676
Node: Python 3 13 1 final2937732
Ref: whatsnew/changelog python-3-13-1-final2937853
Ref: 16932937853
Node: macOS<6>2938362
Ref: whatsnew/changelog id842938445
Ref: 16942938445
Ref: macOS<6>-Footnote-12938586
Node: Windows<9>2938642
Ref: whatsnew/changelog id852938748
Ref: 16952938748
Ref: Windows<9>-Footnote-12939818
Ref: Windows<9>-Footnote-22939874
Ref: Windows<9>-Footnote-32939930
Ref: Windows<9>-Footnote-42939986
Ref: Windows<9>-Footnote-52940042
Ref: Windows<9>-Footnote-62940098
Ref: Windows<9>-Footnote-72940154
Ref: Windows<9>-Footnote-82940210
Ref: Windows<9>-Footnote-92940266
Node: Tools/Demos<7>2940322
Ref: whatsnew/changelog id862940429
Ref: 16962940429
Ref: Tools/Demos<7>-Footnote-12940765
Ref: Tools/Demos<7>-Footnote-22940821
Node: Tests<10>2940877
Ref: whatsnew/changelog id872940986
Ref: 16972940986
Ref: Tests<10>-Footnote-12941508
Ref: Tests<10>-Footnote-22941564
Ref: Tests<10>-Footnote-32941620
Node: Security<10>2941676
Ref: whatsnew/changelog id882941782
Ref: 16982941782
Ref: Security<10>-Footnote-12942310
Ref: Security<10>-Footnote-22942366
Ref: Security<10>-Footnote-32942422
Node: Library<17>2942478
Ref: whatsnew/changelog id892942582
Ref: 16992942582
Ref: Library<17>-Footnote-12964146
Ref: Library<17>-Footnote-22964202
Ref: Library<17>-Footnote-32964258
Ref: Library<17>-Footnote-42964314
Ref: Library<17>-Footnote-52964370
Ref: Library<17>-Footnote-62964426
Ref: Library<17>-Footnote-72964482
Ref: Library<17>-Footnote-82964538
Ref: Library<17>-Footnote-92964594
Ref: Library<17>-Footnote-102964650
Ref: Library<17>-Footnote-112964707
Ref: Library<17>-Footnote-122964764
Ref: Library<17>-Footnote-132964821
Ref: Library<17>-Footnote-142964878
Ref: Library<17>-Footnote-152964934
Ref: Library<17>-Footnote-162964990
Ref: Library<17>-Footnote-172965047
Ref: Library<17>-Footnote-182965104
Ref: Library<17>-Footnote-192965161
Ref: Library<17>-Footnote-202965218
Ref: Library<17>-Footnote-212965275
Ref: Library<17>-Footnote-222965332
Ref: Library<17>-Footnote-232965389
Ref: Library<17>-Footnote-242965446
Ref: Library<17>-Footnote-252965503
Ref: Library<17>-Footnote-262965560
Ref: Library<17>-Footnote-272965617
Ref: Library<17>-Footnote-282965674
Ref: Library<17>-Footnote-292965731
Ref: Library<17>-Footnote-302965788
Ref: Library<17>-Footnote-312965845
Ref: Library<17>-Footnote-322965902
Ref: Library<17>-Footnote-332965959
Ref: Library<17>-Footnote-342966016
Ref: Library<17>-Footnote-352966073
Ref: Library<17>-Footnote-362966130
Ref: Library<17>-Footnote-372966187
Ref: Library<17>-Footnote-382966244
Ref: Library<17>-Footnote-392966301
Ref: Library<17>-Footnote-402966358
Ref: Library<17>-Footnote-412966415
Ref: Library<17>-Footnote-422966472
Ref: Library<17>-Footnote-432966529
Ref: Library<17>-Footnote-442966586
Ref: Library<17>-Footnote-452966643
Ref: Library<17>-Footnote-462966700
Ref: Library<17>-Footnote-472966757
Ref: Library<17>-Footnote-482966814
Ref: Library<17>-Footnote-492966871
Ref: Library<17>-Footnote-502966928
Ref: Library<17>-Footnote-512966985
Ref: Library<17>-Footnote-522967042
Ref: Library<17>-Footnote-532967099
Ref: Library<17>-Footnote-542967156
Ref: Library<17>-Footnote-552967213
Ref: Library<17>-Footnote-562967270
Ref: Library<17>-Footnote-572967327
Ref: Library<17>-Footnote-582967384
Ref: Library<17>-Footnote-592967441
Ref: Library<17>-Footnote-602967498
Ref: Library<17>-Footnote-612967555
Ref: Library<17>-Footnote-622967612
Ref: Library<17>-Footnote-632967669
Ref: Library<17>-Footnote-642967725
Ref: Library<17>-Footnote-652967782
Ref: Library<17>-Footnote-662967839
Ref: Library<17>-Footnote-672967896
Ref: Library<17>-Footnote-682967953
Ref: Library<17>-Footnote-692968010
Ref: Library<17>-Footnote-702968067
Ref: Library<17>-Footnote-712968123
Ref: Library<17>-Footnote-722968179
Ref: Library<17>-Footnote-732968236
Ref: Library<17>-Footnote-742968293
Ref: Library<17>-Footnote-752968350
Ref: Library<17>-Footnote-762968407
Ref: Library<17>-Footnote-772968464
Ref: Library<17>-Footnote-782968521
Ref: Library<17>-Footnote-792968578
Ref: Library<17>-Footnote-802968634
Ref: Library<17>-Footnote-812968691
Ref: Library<17>-Footnote-822968748
Ref: Library<17>-Footnote-832968805
Ref: Library<17>-Footnote-842968862
Ref: Library<17>-Footnote-852968919
Ref: Library<17>-Footnote-862968976
Ref: Library<17>-Footnote-872969032
Ref: Library<17>-Footnote-882969089
Ref: Library<17>-Footnote-892969145
Ref: Library<17>-Footnote-902969201
Ref: Library<17>-Footnote-912969258
Ref: Library<17>-Footnote-922969315
Ref: Library<17>-Footnote-932969371
Ref: Library<17>-Footnote-942969428
Ref: Library<17>-Footnote-952969485
Ref: Library<17>-Footnote-962969541
Ref: Library<17>-Footnote-972969597
Ref: Library<17>-Footnote-982969653
Ref: Library<17>-Footnote-992969709
Ref: Library<17>-Footnote-1002969766
Ref: Library<17>-Footnote-1012969823
Ref: Library<17>-Footnote-1022969881
Ref: Library<17>-Footnote-1032969939
Ref: Library<17>-Footnote-1042969997
Ref: Library<17>-Footnote-1052970055
Ref: Library<17>-Footnote-1062970113
Ref: Library<17>-Footnote-1072970171
Ref: Library<17>-Footnote-1082970229
Ref: Library<17>-Footnote-1092970286
Ref: Library<17>-Footnote-1102970344
Ref: Library<17>-Footnote-1112970402
Ref: Library<17>-Footnote-1122970460
Ref: Library<17>-Footnote-1132970518
Ref: Library<17>-Footnote-1142970575
Ref: Library<17>-Footnote-1152970632
Ref: Library<17>-Footnote-1162970699
Node: IDLE<7>2970766
Ref: whatsnew/changelog id902970875
Ref: 16b22970875
Ref: IDLE<7>-Footnote-12971096
Node: Documentation<10>2971152
Ref: whatsnew/changelog id912971271
Ref: 16b32971271
Ref: Documentation<10>-Footnote-12973306
Ref: Documentation<10>-Footnote-22973362
Ref: Documentation<10>-Footnote-32973418
Ref: Documentation<10>-Footnote-42973474
Ref: Documentation<10>-Footnote-52973530
Ref: Documentation<10>-Footnote-62973585
Ref: Documentation<10>-Footnote-72973641
Ref: Documentation<10>-Footnote-82973696
Node: Core and Builtins<14>2973761
Ref: whatsnew/changelog id922973884
Ref: 16b82973884
Ref: Core and Builtins<14>-Footnote-12974908
Ref: Core and Builtins<14>-Footnote-22974964
Ref: Core and Builtins<14>-Footnote-32975020
Ref: Core and Builtins<14>-Footnote-42975076
Ref: Core and Builtins<14>-Footnote-52975132
Ref: Core and Builtins<14>-Footnote-62975188
Node: Library<18>2975244
Ref: whatsnew/changelog id932975371
Ref: 16bc2975371
Ref: Library<18>-Footnote-12975639
Node: Core and Builtins<15>2975695
Ref: whatsnew/changelog id942975812
Ref: 16bd2975812
Ref: Core and Builtins<15>-Footnote-12978998
Ref: Core and Builtins<15>-Footnote-22979054
Ref: Core and Builtins<15>-Footnote-32979110
Ref: Core and Builtins<15>-Footnote-42979166
Ref: Core and Builtins<15>-Footnote-52979222
Ref: Core and Builtins<15>-Footnote-62979278
Ref: Core and Builtins<15>-Footnote-72979334
Ref: Core and Builtins<15>-Footnote-82979390
Ref: Core and Builtins<15>-Footnote-92979446
Ref: Core and Builtins<15>-Footnote-102979502
Ref: Core and Builtins<15>-Footnote-112979559
Ref: Core and Builtins<15>-Footnote-122979616
Ref: Core and Builtins<15>-Footnote-132979673
Ref: Core and Builtins<15>-Footnote-142979730
Ref: Core and Builtins<15>-Footnote-152979787
Ref: Core and Builtins<15>-Footnote-162979844
Ref: Core and Builtins<15>-Footnote-172979901
Node: Library<19>2979958
Ref: whatsnew/changelog id952980085
Ref: 16c22980085
Ref: Library<19>-Footnote-12980435
Ref: Library<19>-Footnote-22980491
Node: Core and Builtins<16>2980547
Ref: whatsnew/changelog id962980661
Ref: 16c32980661
Ref: Core and Builtins<16>-Footnote-12980943
Node: C API<8>2980999
Ref: whatsnew/changelog id972981110
Ref: 16c42981110
Ref: C API<8>-Footnote-12981727
Ref: C API<8>-Footnote-22981783
Ref: C API<8>-Footnote-32981839
Node: Build<8>2981904
Ref: whatsnew/changelog id982981985
Ref: 16c52981985
Ref: Build<8>-Footnote-12982844
Ref: Build<8>-Footnote-22982900
Ref: Build<8>-Footnote-32982955
Ref: Build<8>-Footnote-42983011
Ref: Build<8>-Footnote-52983076
Ref: Build<8>-Footnote-62983131
Ref: Build<8>-Footnote-72983187
Ref: Build<8>-Footnote-82983243
Ref: Build<8>-Footnote-92983299
Node: Python 3 13 0 final2983355
Ref: whatsnew/changelog python-3-13-0-final2983490
Ref: 16c62983490
Node: Library<20>2983653
Ref: whatsnew/changelog id992983750
Ref: 16c72983750
Ref: Library<20>-Footnote-12983974
Node: Core and Builtins<17>2984030
Ref: whatsnew/changelog id1002984127
Ref: 16c82984127
Ref: Core and Builtins<17>-Footnote-12984344
Node: Python 3 13 0 release candidate 32984400
Ref: whatsnew/changelog python-3-13-0-release-candidate-32984549
Ref: 16c92984549
Node: macOS<7>2984894
Ref: whatsnew/changelog id1012984992
Ref: 16ca2984992
Ref: macOS<7>-Footnote-12985155
Node: Windows<10>2985211
Ref: whatsnew/changelog id1022985327
Ref: 16cb2985327
Ref: Windows<10>-Footnote-12985729
Ref: Windows<10>-Footnote-22985785
Ref: Windows<10>-Footnote-32985841
Node: Tests<11>2985897
Ref: whatsnew/changelog id1032986016
Ref: 16cc2986016
Ref: Tests<11>-Footnote-12986156
Node: Library<21>2986212
Ref: whatsnew/changelog id1042986327
Ref: 16cd2986327
Ref: Library<21>-Footnote-12988895
Ref: Library<21>-Footnote-22988951
Ref: Library<21>-Footnote-32989007
Ref: Library<21>-Footnote-42989063
Ref: Library<21>-Footnote-52989119
Ref: Library<21>-Footnote-62989175
Ref: Library<21>-Footnote-72989230
Ref: Library<21>-Footnote-82989286
Ref: Library<21>-Footnote-92989342
Ref: Library<21>-Footnote-102989398
Ref: Library<21>-Footnote-112989455
Ref: Library<21>-Footnote-122989512
Ref: Library<21>-Footnote-132989569
Ref: Library<21>-Footnote-142989626
Ref: Library<21>-Footnote-152989683
Ref: Library<21>-Footnote-162989740
Node: IDLE<8>2989806
Ref: whatsnew/changelog id1052989929
Ref: 16d02989929
Ref: IDLE<8>-Footnote-12990168
Ref: IDLE<8>-Footnote-22990224
Node: Documentation<11>2990280
Ref: whatsnew/changelog id1062990413
Ref: 16d12990413
Ref: Documentation<11>-Footnote-12990777
Ref: Documentation<11>-Footnote-22990833
Node: Core and Builtins<18>2990889
Ref: whatsnew/changelog id1072991023
Ref: 16d22991023
Ref: Core and Builtins<18>-Footnote-12992920
Ref: Core and Builtins<18>-Footnote-22992976
Ref: Core and Builtins<18>-Footnote-32993032
Ref: Core and Builtins<18>-Footnote-42993088
Ref: Core and Builtins<18>-Footnote-52993144
Ref: Core and Builtins<18>-Footnote-62993200
Ref: Core and Builtins<18>-Footnote-72993256
Ref: Core and Builtins<18>-Footnote-82993312
Ref: Core and Builtins<18>-Footnote-92993367
Ref: Core and Builtins<18>-Footnote-102993423
Ref: Core and Builtins<18>-Footnote-112993479
Node: C API<9>2993536
Ref: whatsnew/changelog id1082993661
Ref: 16d32993661
Ref: C API<9>-Footnote-12993986
Ref: C API<9>-Footnote-22994042
Node: Build<9>2994098
Ref: whatsnew/changelog id1092994193
Ref: 16d42994193
Ref: Build<9>-Footnote-12994512
Ref: Build<9>-Footnote-22994568
Node: Python 3 13 0 release candidate 22994624
Ref: whatsnew/changelog python-3-13-0-release-candidate-22994787
Ref: 16d52994787
Node: macOS<8>2995179
Ref: whatsnew/changelog id1102995277
Ref: 16d62995277
Ref: macOS<8>-Footnote-12995419
Node: Windows<11>2995475
Ref: whatsnew/changelog id1112995596
Ref: 16d72995596
Ref: Windows<11>-Footnote-12996053
Ref: Windows<11>-Footnote-22996109
Ref: Windows<11>-Footnote-32996165
Ref: Windows<11>-Footnote-42996221
Node: Tools/Demos<8>2996276
Ref: whatsnew/changelog id1122996398
Ref: 16d82996398
Ref: Tools/Demos<8>-Footnote-12996604
Node: Tests<12>2996660
Ref: whatsnew/changelog id1132996783
Ref: 16d92996783
Ref: Tests<12>-Footnote-12997086
Ref: Tests<12>-Footnote-22997142
Node: Security<11>2997198
Ref: whatsnew/changelog id1142997318
Ref: 16da2997318
Ref: Security<11>-Footnote-12997563
Ref: Security<11>-Footnote-22997619
Node: Library<22>2997675
Ref: whatsnew/changelog id1152997793
Ref: 16db2997793
Ref: Library<22>-Footnote-13002856
Ref: Library<22>-Footnote-23002912
Ref: Library<22>-Footnote-33002968
Ref: Library<22>-Footnote-43003024
Ref: Library<22>-Footnote-53003095
Ref: Library<22>-Footnote-63003151
Ref: Library<22>-Footnote-73003207
Ref: Library<22>-Footnote-83003263
Ref: Library<22>-Footnote-93003319
Ref: Library<22>-Footnote-103003375
Ref: Library<22>-Footnote-113003432
Ref: Library<22>-Footnote-123003489
Ref: Library<22>-Footnote-133003545
Ref: Library<22>-Footnote-143003602
Ref: Library<22>-Footnote-153003659
Ref: Library<22>-Footnote-163003716
Ref: Library<22>-Footnote-173003773
Ref: Library<22>-Footnote-183003830
Ref: Library<22>-Footnote-193003887
Ref: Library<22>-Footnote-203003944
Ref: Library<22>-Footnote-213004001
Ref: Library<22>-Footnote-223004058
Ref: Library<22>-Footnote-233004115
Ref: Library<22>-Footnote-243004172
Ref: Library<22>-Footnote-253004228
Ref: Library<22>-Footnote-263004285
Ref: Library<22>-Footnote-273004341
Ref: Library<22>-Footnote-283004398
Ref: Library<22>-Footnote-293004455
Ref: Library<22>-Footnote-303004512
Ref: Library<22>-Footnote-313004569
Ref: Library<22>-Footnote-323004626
Ref: Library<22>-Footnote-333004683
Ref: Library<22>-Footnote-343004740
Node: IDLE<9>3004797
Ref: whatsnew/changelog id1163004914
Ref: 16e63004914
Ref: IDLE<9>-Footnote-13005164
Node: Library<23>3005220
Ref: whatsnew/changelog id1173005347
Ref: 16e73005347
Ref: Library<23>-Footnote-13005578
Node: Core and Builtins<19>3005634
Ref: whatsnew/changelog id1183005763
Ref: 16e83005763
Ref: Core and Builtins<19>-Footnote-13009275
Ref: Core and Builtins<19>-Footnote-23009331
Ref: Core and Builtins<19>-Footnote-33009387
Ref: Core and Builtins<19>-Footnote-43009443
Ref: Core and Builtins<19>-Footnote-53009499
Ref: Core and Builtins<19>-Footnote-63009555
Ref: Core and Builtins<19>-Footnote-73009611
Ref: Core and Builtins<19>-Footnote-83009667
Ref: Core and Builtins<19>-Footnote-93009723
Ref: Core and Builtins<19>-Footnote-103009779
Ref: Core and Builtins<19>-Footnote-113009836
Ref: Core and Builtins<19>-Footnote-123009893
Ref: Core and Builtins<19>-Footnote-133009950
Ref: Core and Builtins<19>-Footnote-143010007
Ref: Core and Builtins<19>-Footnote-153010064
Ref: Core and Builtins<19>-Footnote-163010121
Ref: Core and Builtins<19>-Footnote-173010178
Ref: Core and Builtins<19>-Footnote-183010235
Ref: Core and Builtins<19>-Footnote-193010292
Ref: Core and Builtins<19>-Footnote-203010349
Ref: Core and Builtins<19>-Footnote-213010406
Ref: Core and Builtins<19>-Footnote-223010463
Ref: Core and Builtins<19>-Footnote-233010520
Ref: Core and Builtins<19>-Footnote-243010577
Ref: Core and Builtins<19>-Footnote-253010633
Ref: Core and Builtins<19>-Footnote-263010689
Node: C API<10>3010746
Ref: whatsnew/changelog id1193010873
Ref: 16ea3010873
Ref: C API<10>-Footnote-13011111
Node: Build<10>3011167
Ref: whatsnew/changelog id1203011264
Ref: 16eb3011264
Ref: Build<10>-Footnote-13012161
Ref: Build<10>-Footnote-23012217
Ref: Build<10>-Footnote-33012273
Ref: Build<10>-Footnote-43012329
Ref: Build<10>-Footnote-53012385
Node: Python 3 13 0 release candidate 13012441
Ref: whatsnew/changelog python-3-13-0-release-candidate-13012591
Ref: 16ec3012591
Node: Tests<13>3012886
Ref: whatsnew/changelog id1213012986
Ref: 16ed3012986
Ref: Tests<13>-Footnote-13013398
Ref: Tests<13>-Footnote-23013453
Node: Security<12>3013508
Ref: whatsnew/changelog id1223013628
Ref: 16f03013628
Ref: Security<12>-Footnote-13014272
Ref: Security<12>-Footnote-23014328
Node: Library<24>3014384
Ref: whatsnew/changelog id1233014503
Ref: 16f13014503
Ref: Library<24>-Footnote-13016510
Ref: Library<24>-Footnote-23016566
Ref: Library<24>-Footnote-33016622
Ref: Library<24>-Footnote-43016678
Ref: Library<24>-Footnote-53016734
Ref: Library<24>-Footnote-63016790
Ref: Library<24>-Footnote-73016846
Ref: Library<24>-Footnote-83016901
Ref: Library<24>-Footnote-93016957
Ref: Library<24>-Footnote-103017013
Ref: Library<24>-Footnote-113017070
Ref: Library<24>-Footnote-123017126
Ref: Library<24>-Footnote-133017183
Node: IDLE<10>3017240
Ref: whatsnew/changelog id1243017368
Ref: 16f63017368
Ref: IDLE<10>-Footnote-13017580
Node: Core and Builtins<20>3017636
Ref: whatsnew/changelog id1253017762
Ref: 16f73017762
Ref: Core and Builtins<20>-Footnote-13018791
Ref: Core and Builtins<20>-Footnote-23018847
Ref: Core and Builtins<20>-Footnote-33018903
Ref: Core and Builtins<20>-Footnote-43018959
Ref: Core and Builtins<20>-Footnote-53019015
Ref: Core and Builtins<20>-Footnote-63019071
Ref: Core and Builtins<20>-Footnote-73019127
Node: C API<11>3019183
Ref: whatsnew/changelog id1263019310
Ref: 16f93019310
Ref: C API<11>-Footnote-13019637
Ref: C API<11>-Footnote-23019693
Node: Build<11>3019749
Ref: whatsnew/changelog id1273019846
Ref: 16fb3019846
Ref: Build<11>-Footnote-13020069
Node: Python 3 13 0 beta 43020125
Ref: whatsnew/changelog python-3-13-0-beta-43020262
Ref: 16fd3020262
Node: Tests<14>3020541
Ref: whatsnew/changelog id1283020627
Ref: 16fe3020627
Ref: Tests<14>-Footnote-13021520
Ref: Tests<14>-Footnote-23021576
Ref: Tests<14>-Footnote-33021632
Ref: Tests<14>-Footnote-43021688
Node: Library<25>3021744
Ref: whatsnew/changelog id1293021847
Ref: 17003021847
Ref: Library<25>-Footnote-13024326
Ref: Library<25>-Footnote-23024381
Ref: Library<25>-Footnote-33024437
Ref: Library<25>-Footnote-43024493
Ref: Library<25>-Footnote-53024549
Ref: Library<25>-Footnote-63024605
Ref: Library<25>-Footnote-73024660
Ref: Library<25>-Footnote-83024716
Ref: Library<25>-Footnote-93024772
Ref: Library<25>-Footnote-103024828
Ref: Library<25>-Footnote-113024885
Ref: Library<25>-Footnote-123024942
Ref: Library<25>-Footnote-133024999
Ref: Library<25>-Footnote-143025056
Node: IDLE<11>3025113
Ref: whatsnew/changelog id1303025224
Ref: 17023025224
Ref: IDLE<11>-Footnote-13025424
Node: Documentation<12>3025479
Ref: whatsnew/changelog id1313025600
Ref: 17033025600
Ref: Documentation<12>-Footnote-13025970
Ref: Documentation<12>-Footnote-23026026
Node: Core and Builtins<21>3026082
Ref: whatsnew/changelog id1323026204
Ref: 17063026204
Ref: Core and Builtins<21>-Footnote-13028196
Ref: Core and Builtins<21>-Footnote-23028252
Ref: Core and Builtins<21>-Footnote-33028308
Ref: Core and Builtins<21>-Footnote-43028364
Ref: Core and Builtins<21>-Footnote-53028420
Ref: Core and Builtins<21>-Footnote-63028476
Ref: Core and Builtins<21>-Footnote-73028532
Ref: Core and Builtins<21>-Footnote-83028588
Ref: Core and Builtins<21>-Footnote-93028644
Ref: Core and Builtins<21>-Footnote-103028700
Ref: Core and Builtins<21>-Footnote-113028757
Ref: Core and Builtins<21>-Footnote-123028814
Ref: Core and Builtins<21>-Footnote-133028871
Ref: Core and Builtins<21>-Footnote-143028928
Node: C API<12>3028985
Ref: whatsnew/changelog id1333029099
Ref: 17073029099
Ref: C API<12>-Footnote-13030291
Ref: C API<12>-Footnote-23030346
Ref: C API<12>-Footnote-33030402
Ref: C API<12>-Footnote-43030458
Node: Build<12>3030514
Ref: whatsnew/changelog id1343030598
Ref: 170b3030598
Ref: Build<12>-Footnote-13031450
Ref: Build<12>-Footnote-23031506
Ref: Build<12>-Footnote-33031562
Ref: Build<12>-Footnote-43031618
Ref: Build<12>-Footnote-53031674
Ref: Build<12>-Footnote-63031730
Ref: Build<12>-Footnote-73031786
Node: Python 3 13 0 beta 33031842
Ref: whatsnew/changelog python-3-13-0-beta-33031966
Ref: 170c3031966
Node: Core and Builtins<22>3032239
Ref: whatsnew/changelog id1353032337
Ref: 170d3032337
Ref: Core and Builtins<22>-Footnote-13034252
Ref: Core and Builtins<22>-Footnote-23034308
Ref: Core and Builtins<22>-Footnote-33034364
Ref: Core and Builtins<22>-Footnote-43034420
Ref: Core and Builtins<22>-Footnote-53034476
Ref: Core and Builtins<22>-Footnote-63034532
Ref: Core and Builtins<22>-Footnote-73034588
Ref: Core and Builtins<22>-Footnote-83034644
Ref: Core and Builtins<22>-Footnote-93034700
Ref: Core and Builtins<22>-Footnote-103034756
Node: Library<26>3034813
Ref: whatsnew/changelog id1363034941
Ref: 170e3034941
Ref: Library<26>-Footnote-13035214
Node: Core and Builtins<23>3035270
Ref: whatsnew/changelog id1373035388
Ref: 170f3035388
Ref: Core and Builtins<23>-Footnote-13036733
Ref: Core and Builtins<23>-Footnote-23036789
Ref: Core and Builtins<23>-Footnote-33036845
Ref: Core and Builtins<23>-Footnote-43036901
Ref: Core and Builtins<23>-Footnote-53036956
Ref: Core and Builtins<23>-Footnote-63037012
Ref: Core and Builtins<23>-Footnote-73037068
Ref: Core and Builtins<23>-Footnote-83037124
Ref: Core and Builtins<23>-Footnote-93037180
Ref: Core and Builtins<23>-Footnote-103037236
Node: Library<27>3037302
Ref: whatsnew/changelog id1383037418
Ref: 17103037418
Ref: Library<27>-Footnote-13042932
Ref: Library<27>-Footnote-23042988
Ref: Library<27>-Footnote-33043044
Ref: Library<27>-Footnote-43043100
Ref: Library<27>-Footnote-53043156
Ref: Library<27>-Footnote-63043212
Ref: Library<27>-Footnote-73043268
Ref: Library<27>-Footnote-83043324
Ref: Library<27>-Footnote-93043380
Ref: Library<27>-Footnote-103043436
Ref: Library<27>-Footnote-113043493
Ref: Library<27>-Footnote-123043550
Ref: Library<27>-Footnote-133043607
Ref: Library<27>-Footnote-143043664
Ref: Library<27>-Footnote-153043721
Ref: Library<27>-Footnote-163043778
Ref: Library<27>-Footnote-173043834
Ref: Library<27>-Footnote-183043891
Ref: Library<27>-Footnote-193043948
Ref: Library<27>-Footnote-203044005
Ref: Library<27>-Footnote-213044062
Ref: Library<27>-Footnote-223044105
Ref: Library<27>-Footnote-233044162
Ref: Library<27>-Footnote-243044219
Ref: Library<27>-Footnote-253044276
Ref: Library<27>-Footnote-263044332
Ref: Library<27>-Footnote-273044389
Ref: Library<27>-Footnote-283044446
Ref: Library<27>-Footnote-293044503
Ref: Library<27>-Footnote-303044560
Ref: Library<27>-Footnote-313044617
Ref: Library<27>-Footnote-323044674
Ref: Library<27>-Footnote-333044730
Ref: Library<27>-Footnote-343044786
Ref: Library<27>-Footnote-353044843
Ref: Library<27>-Footnote-363044900
Node: Build<13>3044957
Ref: whatsnew/changelog id1393045061
Ref: 17193045061
Ref: Build<13>-Footnote-13045605
Ref: Build<13>-Footnote-23045661
Ref: Build<13>-Footnote-33045717
Ref: Build<13>-Footnote-43045773
Node: C API<13>3045829
Ref: whatsnew/changelog id1403045913
Ref: 171a3045913
Ref: C API<13>-Footnote-13047090
Ref: C API<13>-Footnote-23047146
Ref: C API<13>-Footnote-33047202
Ref: C API<13>-Footnote-43047258
Ref: C API<13>-Footnote-53047314
Ref: C API<13>-Footnote-63047370
Node: Python 3 13 0 beta 23047426
Ref: whatsnew/changelog python-3-13-0-beta-23047550
Ref: 171d3047550
Node: Security<13>3047825
Ref: whatsnew/changelog id1413047924
Ref: 171e3047924
Ref: Security<13>-Footnote-13048441
Ref: Security<13>-Footnote-23048497
Ref: Security<13>-Footnote-33048553
Node: Core and Builtins<24>3048608
Ref: whatsnew/changelog id1423048727
Ref: 171f3048727
Ref: Core and Builtins<24>-Footnote-13051529
Ref: Core and Builtins<24>-Footnote-23051585
Ref: Core and Builtins<24>-Footnote-33051641
Ref: Core and Builtins<24>-Footnote-43051697
Ref: Core and Builtins<24>-Footnote-53051753
Ref: Core and Builtins<24>-Footnote-63051809
Ref: Core and Builtins<24>-Footnote-73051865
Ref: Core and Builtins<24>-Footnote-83051921
Ref: Core and Builtins<24>-Footnote-93051977
Ref: Core and Builtins<24>-Footnote-103052033
Ref: Core and Builtins<24>-Footnote-113052090
Ref: Core and Builtins<24>-Footnote-123052147
Ref: Core and Builtins<24>-Footnote-133052204
Ref: Core and Builtins<24>-Footnote-143052261
Ref: Core and Builtins<24>-Footnote-153052318
Ref: Core and Builtins<24>-Footnote-163052375
Ref: Core and Builtins<24>-Footnote-173052432
Ref: Core and Builtins<24>-Footnote-183052489
Ref: Core and Builtins<24>-Footnote-193052546
Node: Library<28>3052603
Ref: whatsnew/changelog id1433052719
Ref: 17203052719
Ref: Library<28>-Footnote-13059326
Ref: Library<28>-Footnote-23059382
Ref: Library<28>-Footnote-33059438
Ref: Library<28>-Footnote-43059494
Ref: Library<28>-Footnote-53059550
Ref: Library<28>-Footnote-63059605
Ref: Library<28>-Footnote-73059660
Ref: Library<28>-Footnote-83059716
Ref: Library<28>-Footnote-93059771
Ref: Library<28>-Footnote-103059827
Ref: Library<28>-Footnote-113059884
Ref: Library<28>-Footnote-123059941
Ref: Library<28>-Footnote-133059998
Ref: Library<28>-Footnote-143060055
Ref: Library<28>-Footnote-153060112
Ref: Library<28>-Footnote-163060169
Ref: Library<28>-Footnote-173060226
Ref: Library<28>-Footnote-183060283
Ref: Library<28>-Footnote-193060340
Ref: Library<28>-Footnote-203060397
Ref: Library<28>-Footnote-213060454
Ref: Library<28>-Footnote-223060510
Ref: Library<28>-Footnote-233060567
Ref: Library<28>-Footnote-243060624
Ref: Library<28>-Footnote-253060681
Ref: Library<28>-Footnote-263060738
Ref: Library<28>-Footnote-273060795
Ref: Library<28>-Footnote-283060852
Ref: Library<28>-Footnote-293060909
Ref: Library<28>-Footnote-303060966
Ref: Library<28>-Footnote-313061023
Ref: Library<28>-Footnote-323061080
Ref: Library<28>-Footnote-333061137
Ref: Library<28>-Footnote-343061220
Ref: Library<28>-Footnote-353061277
Ref: Library<28>-Footnote-363061334
Ref: Library<28>-Footnote-373061390
Ref: Library<28>-Footnote-383061447
Ref: Library<28>-Footnote-393061503
Ref: Library<28>-Footnote-403061569
Node: Tests<15>3061625
Ref: whatsnew/changelog id1443061729
Ref: 17253061729
Ref: Tests<15>-Footnote-13061923
Node: Build<14>3061979
Ref: whatsnew/changelog id1453062083
Ref: 17263062083
Ref: Build<14>-Footnote-13063129
Ref: Build<14>-Footnote-23063185
Ref: Build<14>-Footnote-33063241
Ref: Build<14>-Footnote-43063297
Ref: Build<14>-Footnote-53063353
Node: Windows<12>3063409
Ref: whatsnew/changelog id1463063513
Ref: 17273063513
Ref: Windows<12>-Footnote-13064448
Ref: Windows<12>-Footnote-23064504
Ref: Windows<12>-Footnote-33064560
Ref: Windows<12>-Footnote-43064616
Ref: Windows<12>-Footnote-53064672
Ref: Windows<12>-Footnote-63064728
Ref: Windows<12>-Footnote-73064784
Node: C API<14>3064840
Ref: whatsnew/changelog id1473064926
Ref: 17283064926
Ref: C API<14>-Footnote-13066313
Ref: C API<14>-Footnote-23066369
Ref: C API<14>-Footnote-33066425
Ref: C API<14>-Footnote-43066481
Ref: C API<14>-Footnote-53066537
Ref: C API<14>-Footnote-63066593
Node: Python 3 13 0 beta 13066649
Ref: whatsnew/changelog python-3-13-0-beta-13066774
Ref: 172b3066774
Node: Security<14>3067170
Ref: whatsnew/changelog id1483067269
Ref: 172c3067269
Ref: Security<14>-Footnote-13067664
Ref: Security<14>-Footnote-23067720
Node: Core and Builtins<25>3067776
Ref: whatsnew/changelog id1493067895
Ref: 172d3067895
Ref: Core and Builtins<25>-Footnote-13069043
Ref: Core and Builtins<25>-Footnote-23069099
Ref: Core and Builtins<25>-Footnote-33069155
Node: Library<29>3069211
Ref: whatsnew/changelog id1503069339
Ref: 172e3069339
Ref: Library<29>-Footnote-13069664
Node: Core and Builtins<26>3069719
Ref: whatsnew/changelog id1513069837
Ref: 172f3069837
Ref: Core and Builtins<26>-Footnote-13077915
Ref: Core and Builtins<26>-Footnote-23077971
Ref: Core and Builtins<26>-Footnote-33078027
Ref: Core and Builtins<26>-Footnote-43078083
Ref: Core and Builtins<26>-Footnote-53078139
Ref: Core and Builtins<26>-Footnote-63078195
Ref: Core and Builtins<26>-Footnote-73078251
Ref: Core and Builtins<26>-Footnote-83078307
Ref: Core and Builtins<26>-Footnote-93078363
Ref: Core and Builtins<26>-Footnote-103078419
Ref: Core and Builtins<26>-Footnote-113078476
Ref: Core and Builtins<26>-Footnote-123078532
Ref: Core and Builtins<26>-Footnote-133078589
Ref: Core and Builtins<26>-Footnote-143078646
Ref: Core and Builtins<26>-Footnote-153078703
Ref: Core and Builtins<26>-Footnote-163078760
Ref: Core and Builtins<26>-Footnote-173078817
Ref: Core and Builtins<26>-Footnote-183078874
Ref: Core and Builtins<26>-Footnote-193078931
Ref: Core and Builtins<26>-Footnote-203078988
Ref: Core and Builtins<26>-Footnote-213079045
Ref: Core and Builtins<26>-Footnote-223079102
Ref: Core and Builtins<26>-Footnote-233079159
Ref: Core and Builtins<26>-Footnote-243079216
Ref: Core and Builtins<26>-Footnote-253079273
Ref: Core and Builtins<26>-Footnote-263079330
Ref: Core and Builtins<26>-Footnote-273079387
Ref: Core and Builtins<26>-Footnote-283079444
Ref: Core and Builtins<26>-Footnote-293079501
Ref: Core and Builtins<26>-Footnote-303079558
Ref: Core and Builtins<26>-Footnote-313079615
Ref: Core and Builtins<26>-Footnote-323079672
Ref: Core and Builtins<26>-Footnote-333079729
Ref: Core and Builtins<26>-Footnote-343079772
Ref: Core and Builtins<26>-Footnote-353079829
Ref: Core and Builtins<26>-Footnote-363079886
Ref: Core and Builtins<26>-Footnote-373079943
Ref: Core and Builtins<26>-Footnote-383080000
Ref: Core and Builtins<26>-Footnote-393080057
Ref: Core and Builtins<26>-Footnote-403080100
Ref: Core and Builtins<26>-Footnote-413080156
Ref: Core and Builtins<26>-Footnote-423080213
Ref: Core and Builtins<26>-Footnote-433080269
Ref: Core and Builtins<26>-Footnote-443080325
Node: Library<30>3080382
Ref: whatsnew/changelog id1523080506
Ref: 17323080506
Ref: Library<30>-Footnote-13096779
Ref: Library<30>-Footnote-23096835
Ref: Library<30>-Footnote-33096891
Ref: Library<30>-Footnote-43096947
Ref: Library<30>-Footnote-53097003
Ref: Library<30>-Footnote-63097059
Ref: Library<30>-Footnote-73097115
Ref: Library<30>-Footnote-83097171
Ref: Library<30>-Footnote-93097227
Ref: Library<30>-Footnote-103097283
Ref: Library<30>-Footnote-113097340
Ref: Library<30>-Footnote-123097397
Ref: Library<30>-Footnote-133097454
Ref: Library<30>-Footnote-143097511
Ref: Library<30>-Footnote-153097554
Ref: Library<30>-Footnote-163097611
Ref: Library<30>-Footnote-173097668
Ref: Library<30>-Footnote-183097725
Ref: Library<30>-Footnote-193097782
Ref: Library<30>-Footnote-203097839
Ref: Library<30>-Footnote-213097896
Ref: Library<30>-Footnote-223097953
Ref: Library<30>-Footnote-233098010
Ref: Library<30>-Footnote-243098067
Ref: Library<30>-Footnote-253098123
Ref: Library<30>-Footnote-263098180
Ref: Library<30>-Footnote-273098237
Ref: Library<30>-Footnote-283098294
Ref: Library<30>-Footnote-293098351
Ref: Library<30>-Footnote-303098408
Ref: Library<30>-Footnote-313098465
Ref: Library<30>-Footnote-323098508
Ref: Library<30>-Footnote-333098565
Ref: Library<30>-Footnote-343098622
Ref: Library<30>-Footnote-353098679
Ref: Library<30>-Footnote-363098735
Ref: Library<30>-Footnote-373098795
Ref: Library<30>-Footnote-383098851
Ref: Library<30>-Footnote-393098908
Ref: Library<30>-Footnote-403098965
Ref: Library<30>-Footnote-413099022
Ref: Library<30>-Footnote-423099078
Ref: Library<30>-Footnote-433099134
Ref: Library<30>-Footnote-443099177
Ref: Library<30>-Footnote-453099234
Ref: Library<30>-Footnote-463099291
Ref: Library<30>-Footnote-473099348
Ref: Library<30>-Footnote-483099405
Ref: Library<30>-Footnote-493099462
Ref: Library<30>-Footnote-503099519
Ref: Library<30>-Footnote-513099576
Ref: Library<30>-Footnote-523099633
Ref: Library<30>-Footnote-533099690
Ref: Library<30>-Footnote-543099747
Ref: Library<30>-Footnote-553099804
Ref: Library<30>-Footnote-563099861
Ref: Library<30>-Footnote-573099918
Ref: Library<30>-Footnote-583099975
Ref: Library<30>-Footnote-593100032
Ref: Library<30>-Footnote-603100089
Ref: Library<30>-Footnote-613100146
Ref: Library<30>-Footnote-623100203
Ref: Library<30>-Footnote-633100246
Ref: Library<30>-Footnote-643100303
Ref: Library<30>-Footnote-653100360
Ref: Library<30>-Footnote-663100417
Ref: Library<30>-Footnote-673100474
Ref: Library<30>-Footnote-683100517
Ref: Library<30>-Footnote-693100573
Ref: Library<30>-Footnote-703100629
Ref: Library<30>-Footnote-713100686
Ref: Library<30>-Footnote-723100743
Ref: Library<30>-Footnote-733100800
Ref: Library<30>-Footnote-743100856
Ref: Library<30>-Footnote-753100912
Ref: Library<30>-Footnote-763100969
Ref: Library<30>-Footnote-773101026
Ref: Library<30>-Footnote-783101083
Ref: Library<30>-Footnote-793101140
Ref: Library<30>-Footnote-803101196
Ref: Library<30>-Footnote-813101253
Ref: Library<30>-Footnote-823101310
Ref: Library<30>-Footnote-833101366
Ref: Library<30>-Footnote-843101423
Ref: Library<30>-Footnote-853101480
Ref: Library<30>-Footnote-863101536
Ref: Library<30>-Footnote-873101592
Ref: Library<30>-Footnote-883101658
Ref: Library<30>-Footnote-893101724
Ref: Library<30>-Footnote-903101790
Ref: Library<30>-Footnote-913101856
Node: Documentation<13>3101922
Ref: whatsnew/changelog id1533102034
Ref: 17403102034
Ref: Documentation<13>-Footnote-13102216
Node: Build<15>3102272
Ref: whatsnew/changelog id1543102384
Ref: 17413102384
Ref: Build<15>-Footnote-13103333
Ref: Build<15>-Footnote-23103389
Ref: Build<15>-Footnote-33103445
Ref: Build<15>-Footnote-43103501
Ref: Build<15>-Footnote-53103557
Ref: Build<15>-Footnote-63103613
Node: Windows<13>3103669
Ref: whatsnew/changelog id1553103772
Ref: 17423103772
Ref: Windows<13>-Footnote-13104811
Ref: Windows<13>-Footnote-23104867
Ref: Windows<13>-Footnote-33104923
Ref: Windows<13>-Footnote-43104979
Ref: Windows<13>-Footnote-53105035
Ref: Windows<13>-Footnote-63105091
Ref: Windows<13>-Footnote-73105146
Node: macOS<9>3105202
Ref: whatsnew/changelog id1563105304
Ref: 17433105304
Ref: macOS<9>-Footnote-13105748
Ref: macOS<9>-Footnote-23105804
Ref: macOS<9>-Footnote-33105860
Ref: macOS<9>-Footnote-43105916
Node: IDLE<12>3105971
Ref: whatsnew/changelog id1573106071
Ref: 17443106071
Ref: IDLE<12>-Footnote-13106212
Node: C API<15>3106277
Ref: whatsnew/changelog id1583106360
Ref: 17453106360
Ref: C API<15>-Footnote-13107653
Ref: C API<15>-Footnote-23107709
Ref: C API<15>-Footnote-33107765
Ref: C API<15>-Footnote-43107821
Ref: C API<15>-Footnote-53107877
Ref: C API<15>-Footnote-63107933
Ref: C API<15>-Footnote-73107988
Node: Python 3 13 0 alpha 63108044
Ref: whatsnew/changelog python-3-13-0-alpha-63108170
Ref: 174d3108170
Node: Core and Builtins<27>3108525
Ref: whatsnew/changelog id1593108624
Ref: 174e3108624
Ref: Core and Builtins<27>-Footnote-13113291
Ref: Core and Builtins<27>-Footnote-23113347
Ref: Core and Builtins<27>-Footnote-33113403
Ref: Core and Builtins<27>-Footnote-43113459
Ref: Core and Builtins<27>-Footnote-53113515
Ref: Core and Builtins<27>-Footnote-63113571
Ref: Core and Builtins<27>-Footnote-73113627
Ref: Core and Builtins<27>-Footnote-83113683
Ref: Core and Builtins<27>-Footnote-93113738
Ref: Core and Builtins<27>-Footnote-103113785
Ref: Core and Builtins<27>-Footnote-113113842
Ref: Core and Builtins<27>-Footnote-123113899
Ref: Core and Builtins<27>-Footnote-133113956
Ref: Core and Builtins<27>-Footnote-143114013
Ref: Core and Builtins<27>-Footnote-153114070
Ref: Core and Builtins<27>-Footnote-163114127
Ref: Core and Builtins<27>-Footnote-173114184
Ref: Core and Builtins<27>-Footnote-183114241
Ref: Core and Builtins<27>-Footnote-193114298
Node: Library<31>3114355
Ref: whatsnew/changelog id1603114484
Ref: 17523114484
Ref: Library<31>-Footnote-13114830
Ref: Library<31>-Footnote-23114886
Node: Core and Builtins<28>3114941
Ref: whatsnew/changelog id1613115060
Ref: 17533115060
Ref: Core and Builtins<28>-Footnote-13115293
Node: Library<32>3115358
Ref: whatsnew/changelog id1623115483
Ref: 17543115483
Ref: Library<32>-Footnote-13126275
Ref: Library<32>-Footnote-23126331
Ref: Library<32>-Footnote-33126387
Ref: Library<32>-Footnote-43126443
Ref: Library<32>-Footnote-53126499
Ref: Library<32>-Footnote-63126555
Ref: Library<32>-Footnote-73126611
Ref: Library<32>-Footnote-83126667
Ref: Library<32>-Footnote-93126723
Ref: Library<32>-Footnote-103126779
Ref: Library<32>-Footnote-113126836
Ref: Library<32>-Footnote-123126892
Ref: Library<32>-Footnote-133126948
Ref: Library<32>-Footnote-143127005
Ref: Library<32>-Footnote-153127062
Ref: Library<32>-Footnote-163127118
Ref: Library<32>-Footnote-173127175
Ref: Library<32>-Footnote-183127232
Ref: Library<32>-Footnote-193127289
Ref: Library<32>-Footnote-203127346
Ref: Library<32>-Footnote-213127403
Ref: Library<32>-Footnote-223127460
Ref: Library<32>-Footnote-233127517
Ref: Library<32>-Footnote-243127574
Ref: Library<32>-Footnote-253127631
Ref: Library<32>-Footnote-263127688
Ref: Library<32>-Footnote-273127744
Ref: Library<32>-Footnote-283127801
Ref: Library<32>-Footnote-293127858
Ref: Library<32>-Footnote-303127914
Ref: Library<32>-Footnote-313127971
Ref: Library<32>-Footnote-323128028
Ref: Library<32>-Footnote-333128084
Ref: Library<32>-Footnote-343128141
Ref: Library<32>-Footnote-353128209
Ref: Library<32>-Footnote-363128265
Ref: Library<32>-Footnote-373128322
Ref: Library<32>-Footnote-383128379
Ref: Library<32>-Footnote-393128436
Ref: Library<32>-Footnote-403128493
Ref: Library<32>-Footnote-413128549
Ref: Library<32>-Footnote-423128605
Ref: Library<32>-Footnote-433128661
Ref: Library<32>-Footnote-443128718
Ref: Library<32>-Footnote-453128775
Ref: Library<32>-Footnote-463128832
Ref: Library<32>-Footnote-473128889
Ref: Library<32>-Footnote-483128945
Ref: Library<32>-Footnote-493129001
Ref: Library<32>-Footnote-503129058
Ref: Library<32>-Footnote-513129115
Ref: Library<32>-Footnote-523129172
Ref: Library<32>-Footnote-533129229
Ref: Library<32>-Footnote-543129286
Ref: Library<32>-Footnote-553129342
Ref: Library<32>-Footnote-563129399
Ref: Library<32>-Footnote-573129456
Ref: Library<32>-Footnote-583129513
Ref: Library<32>-Footnote-593129569
Ref: Library<32>-Footnote-603129625
Ref: Library<32>-Footnote-613129691
Ref: Library<32>-Footnote-623129757
Ref: Library<32>-Footnote-633129823
Ref: Library<32>-Footnote-643129879
Node: Documentation<14>3129945
Ref: whatsnew/changelog id1633130058
Ref: 175c3130058
Ref: Documentation<14>-Footnote-13130471
Ref: Documentation<14>-Footnote-23130527
Ref: Documentation<14>-Footnote-33130583
Node: Tests<16>3130638
Ref: whatsnew/changelog id1643130749
Ref: 175d3130749
Ref: Tests<16>-Footnote-13131857
Ref: Tests<16>-Footnote-23131912
Ref: Tests<16>-Footnote-33131968
Ref: Tests<16>-Footnote-43132024
Ref: Tests<16>-Footnote-53132080
Ref: Tests<16>-Footnote-63132136
Ref: Tests<16>-Footnote-73132192
Node: Build<16>3132248
Ref: whatsnew/changelog id1653132353
Ref: 175e3132353
Ref: Build<16>-Footnote-13132631
Ref: Build<16>-Footnote-23132687
Ref: Build<16>-Footnote-33132743
Node: Windows<14>3132798
Ref: whatsnew/changelog id1663132903
Ref: 175f3132903
Ref: Windows<14>-Footnote-13134363
Ref: Windows<14>-Footnote-23134419
Ref: Windows<14>-Footnote-33134475
Ref: Windows<14>-Footnote-43134530
Ref: Windows<14>-Footnote-53134586
Ref: Windows<14>-Footnote-63134641
Node: C API<16>3134697
Ref: whatsnew/changelog id1673134784
Ref: 17613134784
Ref: C API<16>-Footnote-13138052
Ref: C API<16>-Footnote-23138108
Ref: C API<16>-Footnote-33138150
Ref: C API<16>-Footnote-43138205
Ref: C API<16>-Footnote-53138261
Ref: C API<16>-Footnote-63138317
Ref: C API<16>-Footnote-73138373
Ref: C API<16>-Footnote-83138429
Ref: C API<16>-Footnote-93138485
Ref: C API<16>-Footnote-103138541
Ref: C API<16>-Footnote-113138598
Ref: C API<16>-Footnote-123138655
Ref: C API<16>-Footnote-133138712
Ref: C API<16>-Footnote-143138769
Ref: C API<16>-Footnote-153138812
Ref: C API<16>-Footnote-163138869
Ref: C API<16>-Footnote-173138926
Ref: C API<16>-Footnote-183138982
Ref: C API<16>-Footnote-193139039
Node: Python 3 13 0 alpha 53139096
Ref: whatsnew/changelog python-3-13-0-alpha-53139223
Ref: 17643139223
Node: Security<15>3139741
Ref: whatsnew/changelog id1683139841
Ref: 17653139841
Ref: Security<15>-Footnote-13140654
Ref: Security<15>-Footnote-23140710
Ref: Security<15>-Footnote-33140766
Node: Core and Builtins<29>3140822
Ref: whatsnew/changelog id1693140942
Ref: 17663140942
Ref: Core and Builtins<29>-Footnote-13142322
Ref: Core and Builtins<29>-Footnote-23142378
Ref: Core and Builtins<29>-Footnote-33142434
Ref: Core and Builtins<29>-Footnote-43142476
Ref: Core and Builtins<29>-Footnote-53142532
Ref: Core and Builtins<29>-Footnote-63142588
Ref: Core and Builtins<29>-Footnote-73142644
Ref: Core and Builtins<29>-Footnote-83142700
Ref: Core and Builtins<29>-Footnote-93142756
Ref: Core and Builtins<29>-Footnote-103142812
Ref: Core and Builtins<29>-Footnote-113142869
Ref: Core and Builtins<29>-Footnote-123142926
Node: Library<33>3142983
Ref: whatsnew/changelog id1703143112
Ref: 17673143112
Ref: Library<33>-Footnote-13143360
Node: Core and Builtins<30>3143416
Ref: whatsnew/changelog id1713143535
Ref: 17683143535
Ref: Core and Builtins<30>-Footnote-13143777
Node: Library<34>3143833
Ref: whatsnew/changelog id1723143962
Ref: 17693143962
Ref: Library<34>-Footnote-13144217
Node: Core and Builtins<31>3144273
Ref: whatsnew/changelog id1733144392
Ref: 176a3144392
Ref: Core and Builtins<31>-Footnote-13145221
Ref: Core and Builtins<31>-Footnote-23145277
Ref: Core and Builtins<31>-Footnote-33145333
Node: Library<35>3145388
Ref: whatsnew/changelog id1743145513
Ref: 176b3145513
Ref: Library<35>-Footnote-13157307
Ref: Library<35>-Footnote-23157363
Ref: Library<35>-Footnote-33157419
Ref: Library<35>-Footnote-43157475
Ref: Library<35>-Footnote-53157531
Ref: Library<35>-Footnote-63157573
Ref: Library<35>-Footnote-73157629
Ref: Library<35>-Footnote-83157685
Ref: Library<35>-Footnote-93157741
Ref: Library<35>-Footnote-103157796
Ref: Library<35>-Footnote-113157852
Ref: Library<35>-Footnote-123157908
Ref: Library<35>-Footnote-133157964
Ref: Library<35>-Footnote-143158020
Ref: Library<35>-Footnote-153158077
Ref: Library<35>-Footnote-163158134
Ref: Library<35>-Footnote-173158190
Ref: Library<35>-Footnote-183158246
Ref: Library<35>-Footnote-193158303
Ref: Library<35>-Footnote-203158359
Ref: Library<35>-Footnote-213158416
Ref: Library<35>-Footnote-223158473
Ref: Library<35>-Footnote-233158530
Ref: Library<35>-Footnote-243158587
Ref: Library<35>-Footnote-253158643
Ref: Library<35>-Footnote-263158699
Ref: Library<35>-Footnote-273158756
Ref: Library<35>-Footnote-283158813
Ref: Library<35>-Footnote-293158870
Ref: Library<35>-Footnote-303158927
Ref: Library<35>-Footnote-313158984
Ref: Library<35>-Footnote-323159041
Ref: Library<35>-Footnote-333159098
Ref: Library<35>-Footnote-343159155
Ref: Library<35>-Footnote-353159212
Ref: Library<35>-Footnote-363159269
Ref: Library<35>-Footnote-373159312
Ref: Library<35>-Footnote-383159369
Ref: Library<35>-Footnote-393159426
Ref: Library<35>-Footnote-403159483
Ref: Library<35>-Footnote-413159540
Ref: Library<35>-Footnote-423159597
Ref: Library<35>-Footnote-433159654
Ref: Library<35>-Footnote-443159711
Ref: Library<35>-Footnote-453159768
Ref: Library<35>-Footnote-463159825
Ref: Library<35>-Footnote-473159882
Ref: Library<35>-Footnote-483159938
Ref: Library<35>-Footnote-493159995
Ref: Library<35>-Footnote-503160052
Ref: Library<35>-Footnote-513160108
Ref: Library<35>-Footnote-523160164
Ref: Library<35>-Footnote-533160221
Ref: Library<35>-Footnote-543160277
Ref: Library<35>-Footnote-553160334
Ref: Library<35>-Footnote-563160390
Ref: Library<35>-Footnote-573160447
Ref: Library<35>-Footnote-583160504
Ref: Library<35>-Footnote-593160560
Ref: Library<35>-Footnote-603160616
Ref: Library<35>-Footnote-613160672
Ref: Library<35>-Footnote-623160738
Ref: Library<35>-Footnote-633160804
Ref: Library<35>-Footnote-643160870
Ref: Library<35>-Footnote-653160936
Ref: Library<35>-Footnote-663161002
Ref: Library<35>-Footnote-673161068
Node: Documentation<15>3161134
Ref: whatsnew/changelog id1753161247
Ref: 17743161247
Ref: Documentation<15>-Footnote-13161503
Ref: Documentation<15>-Footnote-23161559
Ref: Documentation<15>-Footnote-33161615
Node: Tests<17>3161671
Ref: whatsnew/changelog id1763161782
Ref: 17753161782
Ref: Tests<17>-Footnote-13162977
Ref: Tests<17>-Footnote-23163032
Ref: Tests<17>-Footnote-33163087
Ref: Tests<17>-Footnote-43163143
Ref: Tests<17>-Footnote-53163199
Ref: Tests<17>-Footnote-63163255
Ref: Tests<17>-Footnote-73163311
Ref: Tests<17>-Footnote-83163367
Ref: Tests<17>-Footnote-93163423
Node: Build<17>3163479
Ref: whatsnew/changelog id1773163584
Ref: 17763163584
Ref: Build<17>-Footnote-13164496
Ref: Build<17>-Footnote-23164552
Ref: Build<17>-Footnote-33164607
Ref: Build<17>-Footnote-43164663
Ref: Build<17>-Footnote-53164718
Ref: Build<17>-Footnote-63164774
Ref: Build<17>-Footnote-73164830
Ref: Build<17>-Footnote-83164886
Ref: Build<17>-Footnote-93164942
Node: Windows<15>3164998
Ref: whatsnew/changelog id1783165103
Ref: 17773165103
Ref: Windows<15>-Footnote-13166197
Ref: Windows<15>-Footnote-23166253
Ref: Windows<15>-Footnote-33166309
Ref: Windows<15>-Footnote-43166365
Node: macOS<10>3166421
Ref: whatsnew/changelog id1793166525
Ref: 17783166525
Ref: macOS<10>-Footnote-13166657
Node: IDLE<13>3166713
Ref: whatsnew/changelog id1803166820
Ref: 17793166820
Ref: IDLE<13>-Footnote-13167004
Node: Tools/Demos<9>3167059
Ref: whatsnew/changelog id1813167166
Ref: 177a3167166
Ref: Tools/Demos<9>-Footnote-13167409
Ref: Tools/Demos<9>-Footnote-23167465
Node: C API<17>3167530
Ref: whatsnew/changelog id1823167620
Ref: 177b3167620
Ref: C API<17>-Footnote-13168191
Ref: C API<17>-Footnote-23168247
Node: Python 3 13 0 alpha 43168303
Ref: whatsnew/changelog python-3-13-0-alpha-43168430
Ref: 17803168430
Node: Security<16>3168813
Ref: whatsnew/changelog id1833168913
Ref: 17813168913
Ref: Security<16>-Footnote-13169174
Ref: Security<16>-Footnote-23169230
Node: Core and Builtins<32>3169286
Ref: whatsnew/changelog id1843169406
Ref: 17823169406
Ref: Core and Builtins<32>-Footnote-13174710
Ref: Core and Builtins<32>-Footnote-23174766
Ref: Core and Builtins<32>-Footnote-33174822
Ref: Core and Builtins<32>-Footnote-43174878
Ref: Core and Builtins<32>-Footnote-53174934
Ref: Core and Builtins<32>-Footnote-63174990
Ref: Core and Builtins<32>-Footnote-73175046
Ref: Core and Builtins<32>-Footnote-83175102
Ref: Core and Builtins<32>-Footnote-93175158
Ref: Core and Builtins<32>-Footnote-103175214
Ref: Core and Builtins<32>-Footnote-113175270
Ref: Core and Builtins<32>-Footnote-123175327
Ref: Core and Builtins<32>-Footnote-133175384
Ref: Core and Builtins<32>-Footnote-143175441
Ref: Core and Builtins<32>-Footnote-153175498
Ref: Core and Builtins<32>-Footnote-163175555
Ref: Core and Builtins<32>-Footnote-173175612
Ref: Core and Builtins<32>-Footnote-183175669
Ref: Core and Builtins<32>-Footnote-193175726
Ref: Core and Builtins<32>-Footnote-203175783
Ref: Core and Builtins<32>-Footnote-213175840
Ref: Core and Builtins<32>-Footnote-223175897
Ref: Core and Builtins<32>-Footnote-233175954
Ref: Core and Builtins<32>-Footnote-243176011
Ref: Core and Builtins<32>-Footnote-253176068
Ref: Core and Builtins<32>-Footnote-263176125
Ref: Core and Builtins<32>-Footnote-273176182
Ref: Core and Builtins<32>-Footnote-283176245
Ref: Core and Builtins<32>-Footnote-293176302
Ref: Core and Builtins<32>-Footnote-303176358
Node: Library<36>3176415
Ref: whatsnew/changelog id1853176540
Ref: 17873176540
Ref: Library<36>-Footnote-13190517
Ref: Library<36>-Footnote-23190573
Ref: Library<36>-Footnote-33190629
Ref: Library<36>-Footnote-43190685
Ref: Library<36>-Footnote-53190741
Ref: Library<36>-Footnote-63190797
Ref: Library<36>-Footnote-73190853
Ref: Library<36>-Footnote-83190909
Ref: Library<36>-Footnote-93190964
Ref: Library<36>-Footnote-103191019
Ref: Library<36>-Footnote-113191076
Ref: Library<36>-Footnote-123191132
Ref: Library<36>-Footnote-133191189
Ref: Library<36>-Footnote-143191245
Ref: Library<36>-Footnote-153191302
Ref: Library<36>-Footnote-163191359
Ref: Library<36>-Footnote-173191416
Ref: Library<36>-Footnote-183191473
Ref: Library<36>-Footnote-193191530
Ref: Library<36>-Footnote-203191586
Ref: Library<36>-Footnote-213191643
Ref: Library<36>-Footnote-223191700
Ref: Library<36>-Footnote-233191756
Ref: Library<36>-Footnote-243191813
Ref: Library<36>-Footnote-253191870
Ref: Library<36>-Footnote-263191926
Ref: Library<36>-Footnote-273191982
Ref: Library<36>-Footnote-283192038
Ref: Library<36>-Footnote-293192095
Ref: Library<36>-Footnote-303192151
Ref: Library<36>-Footnote-313192208
Ref: Library<36>-Footnote-323192265
Ref: Library<36>-Footnote-333192322
Ref: Library<36>-Footnote-343192379
Ref: Library<36>-Footnote-353192436
Ref: Library<36>-Footnote-363192493
Ref: Library<36>-Footnote-373192549
Ref: Library<36>-Footnote-383192606
Ref: Library<36>-Footnote-393192663
Ref: Library<36>-Footnote-403192720
Ref: Library<36>-Footnote-413192777
Ref: Library<36>-Footnote-423192834
Ref: Library<36>-Footnote-433192878
Ref: Library<36>-Footnote-443192935
Ref: Library<36>-Footnote-453192992
Ref: Library<36>-Footnote-463193049
Ref: Library<36>-Footnote-473193106
Ref: Library<36>-Footnote-483193162
Ref: Library<36>-Footnote-493193219
Ref: Library<36>-Footnote-503193276
Ref: Library<36>-Footnote-513193332
Ref: Library<36>-Footnote-523193389
Ref: Library<36>-Footnote-533193446
Ref: Library<36>-Footnote-543193502
Ref: Library<36>-Footnote-553193559
Ref: Library<36>-Footnote-563193616
Ref: Library<36>-Footnote-573193673
Ref: Library<36>-Footnote-583193729
Ref: Library<36>-Footnote-593193786
Ref: Library<36>-Footnote-603193842
Ref: Library<36>-Footnote-613193899
Ref: Library<36>-Footnote-623193956
Ref: Library<36>-Footnote-633194013
Ref: Library<36>-Footnote-643194069
Ref: Library<36>-Footnote-653194125
Ref: Library<36>-Footnote-663194182
Ref: Library<36>-Footnote-673194239
Ref: Library<36>-Footnote-683194295
Ref: Library<36>-Footnote-693194351
Ref: Library<36>-Footnote-703194408
Ref: Library<36>-Footnote-713194465
Ref: Library<36>-Footnote-723194522
Ref: Library<36>-Footnote-733194578
Ref: Library<36>-Footnote-743194635
Ref: Library<36>-Footnote-753194691
Ref: Library<36>-Footnote-763194748
Ref: Library<36>-Footnote-773194804
Node: Documentation<16>3194870
Ref: whatsnew/changelog id1863194983
Ref: 17993194983
Ref: Documentation<16>-Footnote-13195554
Ref: Documentation<16>-Footnote-23195610
Node: Tests<18>3195666
Ref: whatsnew/changelog id1873195777
Ref: 179a3195777
Ref: Tests<18>-Footnote-13196169
Ref: Tests<18>-Footnote-23196225
Node: Build<18>3196281
Ref: whatsnew/changelog id1883196386
Ref: 179b3196386
Ref: Build<18>-Footnote-13196924
Ref: Build<18>-Footnote-23196980
Ref: Build<18>-Footnote-33197036
Ref: Build<18>-Footnote-43197092
Node: Windows<16>3197148
Ref: whatsnew/changelog id1893197253
Ref: 179c3197253
Ref: Windows<16>-Footnote-13198006
Ref: Windows<16>-Footnote-23198062
Ref: Windows<16>-Footnote-33198118
Ref: Windows<16>-Footnote-43198174
Ref: Windows<16>-Footnote-53198230
Ref: Windows<16>-Footnote-63198286
Ref: Windows<16>-Footnote-73198342
Node: macOS<11>3198397
Ref: whatsnew/changelog id1903198501
Ref: 179d3198501
Ref: macOS<11>-Footnote-13199040
Ref: macOS<11>-Footnote-23199096
Ref: macOS<11>-Footnote-33199152
Ref: macOS<11>-Footnote-43199208
Node: IDLE<14>3199263
Ref: whatsnew/changelog id1913199371
Ref: 179f3199371
Ref: IDLE<14>-Footnote-13199706
Ref: IDLE<14>-Footnote-23199761
Node: Tools/Demos<10>3199817
Ref: whatsnew/changelog id1923199925
Ref: 17a03199925
Ref: Tools/Demos<10>-Footnote-13200538
Ref: Tools/Demos<10>-Footnote-23200594
Ref: Tools/Demos<10>-Footnote-33200650
Node: C API<18>3200706
Ref: whatsnew/changelog id1933200797
Ref: 17a23200797
Ref: C API<18>-Footnote-13202741
Ref: C API<18>-Footnote-23202797
Ref: C API<18>-Footnote-33202853
Ref: C API<18>-Footnote-43202909
Ref: C API<18>-Footnote-53202965
Ref: C API<18>-Footnote-63203021
Ref: C API<18>-Footnote-73203077
Node: Python 3 13 0 alpha 33203133
Ref: whatsnew/changelog python-3-13-0-alpha-33203260
Ref: 17a53203260
Node: Security<17>3203611
Ref: whatsnew/changelog id1943203711
Ref: 17a63203711
Ref: Security<17>-Footnote-13204000
Ref: Security<17>-Footnote-23204056
Node: Core and Builtins<33>3204112
Ref: whatsnew/changelog id1953204232
Ref: 17a73204232
Ref: Core and Builtins<33>-Footnote-13211627
Ref: Core and Builtins<33>-Footnote-23211683
Ref: Core and Builtins<33>-Footnote-33211739
Ref: Core and Builtins<33>-Footnote-43211795
Ref: Core and Builtins<33>-Footnote-53211851
Ref: Core and Builtins<33>-Footnote-63211906
Ref: Core and Builtins<33>-Footnote-73211948
Ref: Core and Builtins<33>-Footnote-83212004
Ref: Core and Builtins<33>-Footnote-93212060
Ref: Core and Builtins<33>-Footnote-103212116
Ref: Core and Builtins<33>-Footnote-113212173
Ref: Core and Builtins<33>-Footnote-123212229
Ref: Core and Builtins<33>-Footnote-133212286
Ref: Core and Builtins<33>-Footnote-143212343
Ref: Core and Builtins<33>-Footnote-153212400
Ref: Core and Builtins<33>-Footnote-163212457
Ref: Core and Builtins<33>-Footnote-173212514
Ref: Core and Builtins<33>-Footnote-183212571
Ref: Core and Builtins<33>-Footnote-193212628
Ref: Core and Builtins<33>-Footnote-203212685
Ref: Core and Builtins<33>-Footnote-213212742
Ref: Core and Builtins<33>-Footnote-223212799
Ref: Core and Builtins<33>-Footnote-233212856
Ref: Core and Builtins<33>-Footnote-243212913
Ref: Core and Builtins<33>-Footnote-253212969
Ref: Core and Builtins<33>-Footnote-263213026
Ref: Core and Builtins<33>-Footnote-273213083
Ref: Core and Builtins<33>-Footnote-283213139
Ref: Core and Builtins<33>-Footnote-293213196
Ref: Core and Builtins<33>-Footnote-303213253
Ref: Core and Builtins<33>-Footnote-313213310
Ref: Core and Builtins<33>-Footnote-323213367
Ref: Core and Builtins<33>-Footnote-333213424
Ref: Core and Builtins<33>-Footnote-343213480
Ref: Core and Builtins<33>-Footnote-353213537
Ref: Core and Builtins<33>-Footnote-363213594
Ref: Core and Builtins<33>-Footnote-373213651
Ref: Core and Builtins<33>-Footnote-383213708
Ref: Core and Builtins<33>-Footnote-393213764
Ref: Core and Builtins<33>-Footnote-403213821
Ref: Core and Builtins<33>-Footnote-413213878
Ref: Core and Builtins<33>-Footnote-423213935
Ref: Core and Builtins<33>-Footnote-433213991
Ref: Core and Builtins<33>-Footnote-443214057
Ref: Core and Builtins<33>-Footnote-453214123
Ref: Core and Builtins<33>-Footnote-463214166
Node: Library<37>3214232
Ref: whatsnew/changelog id1963214357
Ref: 17ac3214357
Ref: Library<37>-Footnote-13239570
Ref: Library<37>-Footnote-23239626
Ref: Library<37>-Footnote-33239682
Ref: Library<37>-Footnote-43239738
Ref: Library<37>-Footnote-53239794
Ref: Library<37>-Footnote-63239850
Ref: Library<37>-Footnote-73239906
Ref: Library<37>-Footnote-83239962
Ref: Library<37>-Footnote-93240018
Ref: Library<37>-Footnote-103240074
Ref: Library<37>-Footnote-113240130
Ref: Library<37>-Footnote-123240187
Ref: Library<37>-Footnote-133240244
Ref: Library<37>-Footnote-143240301
Ref: Library<37>-Footnote-153240358
Ref: Library<37>-Footnote-163240415
Ref: Library<37>-Footnote-173240472
Ref: Library<37>-Footnote-183240529
Ref: Library<37>-Footnote-193240586
Ref: Library<37>-Footnote-203240643
Ref: Library<37>-Footnote-213240699
Ref: Library<37>-Footnote-223240756
Ref: Library<37>-Footnote-233240812
Ref: Library<37>-Footnote-243240869
Ref: Library<37>-Footnote-253240926
Ref: Library<37>-Footnote-263240983
Ref: Library<37>-Footnote-273241040
Ref: Library<37>-Footnote-283241097
Ref: Library<37>-Footnote-293241154
Ref: Library<37>-Footnote-303241211
Ref: Library<37>-Footnote-313241268
Ref: Library<37>-Footnote-323241325
Ref: Library<37>-Footnote-333241381
Ref: Library<37>-Footnote-343241438
Ref: Library<37>-Footnote-353241495
Ref: Library<37>-Footnote-363241552
Ref: Library<37>-Footnote-373241608
Ref: Library<37>-Footnote-383241665
Ref: Library<37>-Footnote-393241722
Ref: Library<37>-Footnote-403241779
Ref: Library<37>-Footnote-413241836
Ref: Library<37>-Footnote-423241893
Ref: Library<37>-Footnote-433241950
Ref: Library<37>-Footnote-443242007
Ref: Library<37>-Footnote-453242064
Ref: Library<37>-Footnote-463242121
Ref: Library<37>-Footnote-473242177
Ref: Library<37>-Footnote-483242234
Ref: Library<37>-Footnote-493242290
Ref: Library<37>-Footnote-503242347
Ref: Library<37>-Footnote-513242404
Ref: Library<37>-Footnote-523242461
Ref: Library<37>-Footnote-533242518
Ref: Library<37>-Footnote-543242575
Ref: Library<37>-Footnote-553242632
Ref: Library<37>-Footnote-563242688
Ref: Library<37>-Footnote-573242745
Ref: Library<37>-Footnote-583242801
Ref: Library<37>-Footnote-593242857
Ref: Library<37>-Footnote-603242913
Ref: Library<37>-Footnote-613242970
Ref: Library<37>-Footnote-623243027
Ref: Library<37>-Footnote-633243083
Ref: Library<37>-Footnote-643243139
Ref: Library<37>-Footnote-653243196
Ref: Library<37>-Footnote-663243253
Ref: Library<37>-Footnote-673243310
Ref: Library<37>-Footnote-683243367
Ref: Library<37>-Footnote-693243424
Ref: Library<37>-Footnote-703243481
Ref: Library<37>-Footnote-713243537
Ref: Library<37>-Footnote-723243594
Ref: Library<37>-Footnote-733243651
Ref: Library<37>-Footnote-743243708
Ref: Library<37>-Footnote-753243765
Ref: Library<37>-Footnote-763243822
Ref: Library<37>-Footnote-773243879
Ref: Library<37>-Footnote-783243935
Ref: Library<37>-Footnote-793243992
Ref: Library<37>-Footnote-803244049
Ref: Library<37>-Footnote-813244106
Ref: Library<37>-Footnote-823244162
Ref: Library<37>-Footnote-833244219
Ref: Library<37>-Footnote-843244276
Ref: Library<37>-Footnote-853244333
Ref: Library<37>-Footnote-863244390
Ref: Library<37>-Footnote-873244446
Ref: Library<37>-Footnote-883244503
Ref: Library<37>-Footnote-893244559
Ref: Library<37>-Footnote-903244616
Ref: Library<37>-Footnote-913244673
Ref: Library<37>-Footnote-923244730
Ref: Library<37>-Footnote-933244787
Ref: Library<37>-Footnote-943244844
Ref: Library<37>-Footnote-953244900
Ref: Library<37>-Footnote-963244957
Ref: Library<37>-Footnote-973245013
Ref: Library<37>-Footnote-983245070
Ref: Library<37>-Footnote-993245126
Ref: Library<37>-Footnote-1003245182
Ref: Library<37>-Footnote-1013245239
Ref: Library<37>-Footnote-1023245297
Ref: Library<37>-Footnote-1033245355
Ref: Library<37>-Footnote-1043245413
Ref: Library<37>-Footnote-1053245471
Ref: Library<37>-Footnote-1063245528
Ref: Library<37>-Footnote-1073245585
Ref: Library<37>-Footnote-1083245643
Ref: Library<37>-Footnote-1093245701
Ref: Library<37>-Footnote-1103245759
Ref: Library<37>-Footnote-1113245816
Ref: Library<37>-Footnote-1123245874
Ref: Library<37>-Footnote-1133245932
Ref: Library<37>-Footnote-1143245989
Ref: Library<37>-Footnote-1153246047
Ref: Library<37>-Footnote-1163246091
Ref: Library<37>-Footnote-1173246149
Ref: Library<37>-Footnote-1183246206
Ref: Library<37>-Footnote-1193246263
Ref: Library<37>-Footnote-1203246320
Ref: Library<37>-Footnote-1213246387
Ref: Library<37>-Footnote-1223246454
Ref: Library<37>-Footnote-1233246521
Ref: Library<37>-Footnote-1243246588
Ref: Library<37>-Footnote-1253246655
Ref: Library<37>-Footnote-1263246722
Ref: Library<37>-Footnote-1273246789
Ref: Library<37>-Footnote-1283246856
Ref: Library<37>-Footnote-1293246923
Ref: Library<37>-Footnote-1303246990
Ref: Library<37>-Footnote-1313247057
Ref: Library<37>-Footnote-1323247124
Ref: Library<37>-Footnote-1333247191
Ref: Library<37>-Footnote-1343247258
Node: Documentation<17>3247325
Ref: whatsnew/changelog id1973247438
Ref: 17c73247438
Ref: Documentation<17>-Footnote-13248006
Ref: Documentation<17>-Footnote-23248062
Ref: Documentation<17>-Footnote-33248118
Ref: Documentation<17>-Footnote-43248173
Node: Tests<19>3248231
Ref: whatsnew/changelog id1983248342
Ref: 17c83248342
Ref: Tests<19>-Footnote-13250287
Ref: Tests<19>-Footnote-23250343
Ref: Tests<19>-Footnote-33250399
Ref: Tests<19>-Footnote-43250455
Ref: Tests<19>-Footnote-53250510
Ref: Tests<19>-Footnote-63250566
Ref: Tests<19>-Footnote-73250622
Ref: Tests<19>-Footnote-83250678
Ref: Tests<19>-Footnote-93250734
Ref: Tests<19>-Footnote-103250790
Node: Build<19>3250856
Ref: whatsnew/changelog id1993250961
Ref: 17c93250961
Ref: Build<19>-Footnote-13252205
Ref: Build<19>-Footnote-23252261
Ref: Build<19>-Footnote-33252317
Ref: Build<19>-Footnote-43252373
Ref: Build<19>-Footnote-53252429
Ref: Build<19>-Footnote-63252485
Ref: Build<19>-Footnote-73252541
Ref: Build<19>-Footnote-83252606
Node: Windows<17>3252671
Ref: whatsnew/changelog id2003252776
Ref: 17ca3252776
Ref: Windows<17>-Footnote-13254617
Ref: Windows<17>-Footnote-23254673
Ref: Windows<17>-Footnote-33254729
Ref: Windows<17>-Footnote-43254785
Ref: Windows<17>-Footnote-53254841
Ref: Windows<17>-Footnote-63254896
Ref: Windows<17>-Footnote-73254951
Ref: Windows<17>-Footnote-83255007
Ref: Windows<17>-Footnote-93255063
Ref: Windows<17>-Footnote-103255118
Ref: Windows<17>-Footnote-113255174
Node: macOS<12>3255240
Ref: whatsnew/changelog id2013255344
Ref: 17cb3255344
Ref: macOS<12>-Footnote-13257754
Ref: macOS<12>-Footnote-23257810
Ref: macOS<12>-Footnote-33257866
Ref: macOS<12>-Footnote-43257922
Ref: macOS<12>-Footnote-53257977
Ref: macOS<12>-Footnote-63258032
Ref: macOS<12>-Footnote-73258087
Ref: macOS<12>-Footnote-83258143
Ref: macOS<12>-Footnote-93258199
Ref: macOS<12>-Footnote-103258255
Ref: macOS<12>-Footnote-113258312
Ref: macOS<12>-Footnote-123258369
Node: IDLE<15>3258426
Ref: whatsnew/changelog id2023258528
Ref: 17cc3258528
Ref: IDLE<15>-Footnote-13259112
Ref: IDLE<15>-Footnote-23259167
Ref: IDLE<15>-Footnote-33259223
Ref: IDLE<15>-Footnote-43259279
Ref: IDLE<15>-Footnote-53259335
Ref: IDLE<15>-Footnote-63259391
Node: C API<19>3259456
Ref: whatsnew/changelog id2033259540
Ref: 17cd3259540
Ref: C API<19>-Footnote-13260271
Ref: C API<19>-Footnote-23260327
Ref: C API<19>-Footnote-33260383
Ref: C API<19>-Footnote-43260439
Node: Python 3 13 0 alpha 23260494
Ref: whatsnew/changelog python-3-13-0-alpha-23260621
Ref: 17ce3260621
Node: Core and Builtins<34>3260942
Ref: whatsnew/changelog id2043261041
Ref: 17cf3261041
Ref: Core and Builtins<34>-Footnote-13268873
Ref: Core and Builtins<34>-Footnote-23268929
Ref: Core and Builtins<34>-Footnote-33268985
Ref: Core and Builtins<34>-Footnote-43269041
Ref: Core and Builtins<34>-Footnote-53269097
Ref: Core and Builtins<34>-Footnote-63269153
Ref: Core and Builtins<34>-Footnote-73269209
Ref: Core and Builtins<34>-Footnote-83269265
Ref: Core and Builtins<34>-Footnote-93269320
Ref: Core and Builtins<34>-Footnote-103269375
Ref: Core and Builtins<34>-Footnote-113269431
Ref: Core and Builtins<34>-Footnote-123269488
Ref: Core and Builtins<34>-Footnote-133269545
Ref: Core and Builtins<34>-Footnote-143269602
Ref: Core and Builtins<34>-Footnote-153269659
Ref: Core and Builtins<34>-Footnote-163269716
Ref: Core and Builtins<34>-Footnote-173269773
Ref: Core and Builtins<34>-Footnote-183269830
Ref: Core and Builtins<34>-Footnote-193269887
Ref: Core and Builtins<34>-Footnote-203269944
Ref: Core and Builtins<34>-Footnote-213270001
Ref: Core and Builtins<34>-Footnote-223270058
Ref: Core and Builtins<34>-Footnote-233270115
Ref: Core and Builtins<34>-Footnote-243270172
Ref: Core and Builtins<34>-Footnote-253270229
Ref: Core and Builtins<34>-Footnote-263270286
Ref: Core and Builtins<34>-Footnote-273270343
Ref: Core and Builtins<34>-Footnote-283270400
Ref: Core and Builtins<34>-Footnote-293270457
Ref: Core and Builtins<34>-Footnote-303270513
Ref: Core and Builtins<34>-Footnote-313270569
Ref: Core and Builtins<34>-Footnote-323270626
Ref: Core and Builtins<34>-Footnote-333270683
Ref: Core and Builtins<34>-Footnote-343270740
Ref: Core and Builtins<34>-Footnote-353270797
Ref: Core and Builtins<34>-Footnote-363270854
Ref: Core and Builtins<34>-Footnote-373270911
Ref: Core and Builtins<34>-Footnote-383270968
Ref: Core and Builtins<34>-Footnote-393271025
Ref: Core and Builtins<34>-Footnote-403271082
Ref: Core and Builtins<34>-Footnote-413271139
Ref: Core and Builtins<34>-Footnote-423271196
Ref: Core and Builtins<34>-Footnote-433271253
Ref: Core and Builtins<34>-Footnote-443271309
Ref: Core and Builtins<34>-Footnote-453271375
Ref: Core and Builtins<34>-Footnote-463271432
Ref: Core and Builtins<34>-Footnote-473271498
Ref: Core and Builtins<34>-Footnote-483271555
Ref: Core and Builtins<34>-Footnote-493271612
Ref: Core and Builtins<34>-Footnote-503271669
Node: Library<38>3271735
Ref: whatsnew/changelog id2053271852
Ref: 17d23271852
Ref: Library<38>-Footnote-13282425
Ref: Library<38>-Footnote-23282481
Ref: Library<38>-Footnote-33282537
Ref: Library<38>-Footnote-43282593
Ref: Library<38>-Footnote-53282649
Ref: Library<38>-Footnote-63282705
Ref: Library<38>-Footnote-73282761
Ref: Library<38>-Footnote-83282817
Ref: Library<38>-Footnote-93282873
Ref: Library<38>-Footnote-103282929
Ref: Library<38>-Footnote-113282986
Ref: Library<38>-Footnote-123283042
Ref: Library<38>-Footnote-133283099
Ref: Library<38>-Footnote-143283156
Ref: Library<38>-Footnote-153283213
Ref: Library<38>-Footnote-163283270
Ref: Library<38>-Footnote-173283327
Ref: Library<38>-Footnote-183283384
Ref: Library<38>-Footnote-193283441
Ref: Library<38>-Footnote-203283497
Ref: Library<38>-Footnote-213283554
Ref: Library<38>-Footnote-223283611
Ref: Library<38>-Footnote-233283667
Ref: Library<38>-Footnote-243283724
Ref: Library<38>-Footnote-253283780
Ref: Library<38>-Footnote-263283837
Ref: Library<38>-Footnote-273283894
Ref: Library<38>-Footnote-283283951
Ref: Library<38>-Footnote-293284008
Ref: Library<38>-Footnote-303284065
Ref: Library<38>-Footnote-313284122
Ref: Library<38>-Footnote-323284179
Ref: Library<38>-Footnote-333284236
Ref: Library<38>-Footnote-343284293
Ref: Library<38>-Footnote-353284350
Ref: Library<38>-Footnote-363284407
Ref: Library<38>-Footnote-373284464
Ref: Library<38>-Footnote-383284521
Ref: Library<38>-Footnote-393284577
Ref: Library<38>-Footnote-403284633
Ref: Library<38>-Footnote-413284690
Ref: Library<38>-Footnote-423284747
Ref: Library<38>-Footnote-433284804
Ref: Library<38>-Footnote-443284860
Ref: Library<38>-Footnote-453284916
Ref: Library<38>-Footnote-463284973
Ref: Library<38>-Footnote-473285030
Ref: Library<38>-Footnote-483285087
Ref: Library<38>-Footnote-493285144
Ref: Library<38>-Footnote-503285200
Ref: Library<38>-Footnote-513285257
Ref: Library<38>-Footnote-523285314
Ref: Library<38>-Footnote-533285371
Ref: Library<38>-Footnote-543285427
Ref: Library<38>-Footnote-553285483
Ref: Library<38>-Footnote-563285539
Ref: Library<38>-Footnote-573285596
Ref: Library<38>-Footnote-583285653
Ref: Library<38>-Footnote-593285709
Ref: Library<38>-Footnote-603285765
Ref: Library<38>-Footnote-613285850
Ref: Library<38>-Footnote-623285906
Node: Tests<20>3285962
Ref: whatsnew/changelog id2063286067
Ref: 17e63286067
Ref: Tests<20>-Footnote-13287653
Ref: Tests<20>-Footnote-23287709
Ref: Tests<20>-Footnote-33287765
Ref: Tests<20>-Footnote-43287821
Ref: Tests<20>-Footnote-53287877
Ref: Tests<20>-Footnote-63287933
Ref: Tests<20>-Footnote-73287989
Ref: Tests<20>-Footnote-83288045
Node: Build<20>3288101
Ref: whatsnew/changelog id2073288206
Ref: 17e73288206
Ref: Build<20>-Footnote-13289192
Ref: Build<20>-Footnote-23289247
Ref: Build<20>-Footnote-33289303
Ref: Build<20>-Footnote-43289353
Ref: Build<20>-Footnote-53289409
Ref: Build<20>-Footnote-63289465
Node: Windows<18>3289520
Ref: whatsnew/changelog id2083289625
Ref: 17e83289625
Ref: Windows<18>-Footnote-13290079
Ref: Windows<18>-Footnote-23290135
Ref: Windows<18>-Footnote-33290191
Node: macOS<13>3290247
Ref: whatsnew/changelog id2093290351
Ref: 17ea3290351
Ref: macOS<13>-Footnote-13291282
Ref: macOS<13>-Footnote-23291337
Ref: macOS<13>-Footnote-33291393
Ref: macOS<13>-Footnote-43291449
Ref: macOS<13>-Footnote-53291504
Node: IDLE<16>3291559
Ref: whatsnew/changelog id2103291667
Ref: 17eb3291667
Ref: IDLE<16>-Footnote-13292005
Node: Tools/Demos<11>3292070
Ref: whatsnew/changelog id2113292178
Ref: 17ec3292178
Ref: Tools/Demos<11>-Footnote-13292535
Node: C API<20>3292591
Ref: whatsnew/changelog id2123292682
Ref: 17ed3292682
Ref: C API<20>-Footnote-13298058
Ref: C API<20>-Footnote-23298114
Ref: C API<20>-Footnote-33298170
Ref: C API<20>-Footnote-43298226
Ref: C API<20>-Footnote-53298282
Ref: C API<20>-Footnote-63298338
Ref: C API<20>-Footnote-73298394
Ref: C API<20>-Footnote-83298450
Ref: C API<20>-Footnote-93298506
Ref: C API<20>-Footnote-103298562
Ref: C API<20>-Footnote-113298619
Ref: C API<20>-Footnote-123298662
Ref: C API<20>-Footnote-133298719
Ref: C API<20>-Footnote-143298776
Ref: C API<20>-Footnote-153298833
Ref: C API<20>-Footnote-163298890
Ref: C API<20>-Footnote-173298947
Ref: C API<20>-Footnote-183299003
Ref: C API<20>-Footnote-193299059
Ref: C API<20>-Footnote-203299116
Node: Python 3 13 0 alpha 13299172
Ref: whatsnew/changelog python-3-13-0-alpha-13299298
Ref: 17ee3299298
Node: Security<18>3299681
Ref: whatsnew/changelog id2133299781
Ref: 17ef3299781
Ref: Security<18>-Footnote-13301049
Ref: Security<18>-Footnote-23301105
Ref: Security<18>-Footnote-33301161
Ref: Security<18>-Footnote-43301217
Ref: Security<18>-Footnote-53301273
Ref: Security<18>-Footnote-63301329
Ref: Security<18>-Footnote-73301384
Node: Core and Builtins<35>3301440
Ref: whatsnew/changelog id2143301560
Ref: 17f03301560
Ref: Core and Builtins<35>-Footnote-13332333
Ref: Core and Builtins<35>-Footnote-23332389
Ref: Core and Builtins<35>-Footnote-33332445
Ref: Core and Builtins<35>-Footnote-43332501
Ref: Core and Builtins<35>-Footnote-53332557
Ref: Core and Builtins<35>-Footnote-63332613
Ref: Core and Builtins<35>-Footnote-73332669
Ref: Core and Builtins<35>-Footnote-83332725
Ref: Core and Builtins<35>-Footnote-93332781
Ref: Core and Builtins<35>-Footnote-103332837
Ref: Core and Builtins<35>-Footnote-113332894
Ref: Core and Builtins<35>-Footnote-123332951
Ref: Core and Builtins<35>-Footnote-133333008
Ref: Core and Builtins<35>-Footnote-143333065
Ref: Core and Builtins<35>-Footnote-153333122
Ref: Core and Builtins<35>-Footnote-163333179
Ref: Core and Builtins<35>-Footnote-173333236
Ref: Core and Builtins<35>-Footnote-183333293
Ref: Core and Builtins<35>-Footnote-193333350
Ref: Core and Builtins<35>-Footnote-203333407
Ref: Core and Builtins<35>-Footnote-213333464
Ref: Core and Builtins<35>-Footnote-223333521
Ref: Core and Builtins<35>-Footnote-233333578
Ref: Core and Builtins<35>-Footnote-243333635
Ref: Core and Builtins<35>-Footnote-253333692
Ref: Core and Builtins<35>-Footnote-263333749
Ref: Core and Builtins<35>-Footnote-273333806
Ref: Core and Builtins<35>-Footnote-283333863
Ref: Core and Builtins<35>-Footnote-293333920
Ref: Core and Builtins<35>-Footnote-303333977
Ref: Core and Builtins<35>-Footnote-313334034
Ref: Core and Builtins<35>-Footnote-323334091
Ref: Core and Builtins<35>-Footnote-333334148
Ref: Core and Builtins<35>-Footnote-343334205
Ref: Core and Builtins<35>-Footnote-353334262
Ref: Core and Builtins<35>-Footnote-363334319
Ref: Core and Builtins<35>-Footnote-373334376
Ref: Core and Builtins<35>-Footnote-383334433
Ref: Core and Builtins<35>-Footnote-393334490
Ref: Core and Builtins<35>-Footnote-403334547
Ref: Core and Builtins<35>-Footnote-413334604
Ref: Core and Builtins<35>-Footnote-423334661
Ref: Core and Builtins<35>-Footnote-433334718
Ref: Core and Builtins<35>-Footnote-443334775
Ref: Core and Builtins<35>-Footnote-453334831
Ref: Core and Builtins<35>-Footnote-463334888
Ref: Core and Builtins<35>-Footnote-473334945
Ref: Core and Builtins<35>-Footnote-483335002
Ref: Core and Builtins<35>-Footnote-493335059
Ref: Core and Builtins<35>-Footnote-503335116
Ref: Core and Builtins<35>-Footnote-513335173
Ref: Core and Builtins<35>-Footnote-523335230
Ref: Core and Builtins<35>-Footnote-533335287
Ref: Core and Builtins<35>-Footnote-543335344
Ref: Core and Builtins<35>-Footnote-553335401
Ref: Core and Builtins<35>-Footnote-563335458
Ref: Core and Builtins<35>-Footnote-573335515
Ref: Core and Builtins<35>-Footnote-583335572
Ref: Core and Builtins<35>-Footnote-593335629
Ref: Core and Builtins<35>-Footnote-603335686
Ref: Core and Builtins<35>-Footnote-613335743
Ref: Core and Builtins<35>-Footnote-623335800
Ref: Core and Builtins<35>-Footnote-633335857
Ref: Core and Builtins<35>-Footnote-643335914
Ref: Core and Builtins<35>-Footnote-653335970
Ref: Core and Builtins<35>-Footnote-663336027
Ref: Core and Builtins<35>-Footnote-673336084
Ref: Core and Builtins<35>-Footnote-683336140
Ref: Core and Builtins<35>-Footnote-693336197
Ref: Core and Builtins<35>-Footnote-703336254
Ref: Core and Builtins<35>-Footnote-713336311
Ref: Core and Builtins<35>-Footnote-723336368
Ref: Core and Builtins<35>-Footnote-733336425
Ref: Core and Builtins<35>-Footnote-743336481
Ref: Core and Builtins<35>-Footnote-753336538
Ref: Core and Builtins<35>-Footnote-763336595
Ref: Core and Builtins<35>-Footnote-773336652
Ref: Core and Builtins<35>-Footnote-783336709
Ref: Core and Builtins<35>-Footnote-793336766
Ref: Core and Builtins<35>-Footnote-803336823
Ref: Core and Builtins<35>-Footnote-813336880
Ref: Core and Builtins<35>-Footnote-823336937
Ref: Core and Builtins<35>-Footnote-833336994
Ref: Core and Builtins<35>-Footnote-843337051
Ref: Core and Builtins<35>-Footnote-853337094
Ref: Core and Builtins<35>-Footnote-863337151
Ref: Core and Builtins<35>-Footnote-873337208
Ref: Core and Builtins<35>-Footnote-883337265
Ref: Core and Builtins<35>-Footnote-893337321
Ref: Core and Builtins<35>-Footnote-903337378
Ref: Core and Builtins<35>-Footnote-913337435
Ref: Core and Builtins<35>-Footnote-923337492
Ref: Core and Builtins<35>-Footnote-933337549
Ref: Core and Builtins<35>-Footnote-943337606
Ref: Core and Builtins<35>-Footnote-953337663
Ref: Core and Builtins<35>-Footnote-963337720
Ref: Core and Builtins<35>-Footnote-973337777
Ref: Core and Builtins<35>-Footnote-983337834
Ref: Core and Builtins<35>-Footnote-993337891
Ref: Core and Builtins<35>-Footnote-1003337948
Ref: Core and Builtins<35>-Footnote-1013338006
Ref: Core and Builtins<35>-Footnote-1023338064
Ref: Core and Builtins<35>-Footnote-1033338122
Ref: Core and Builtins<35>-Footnote-1043338180
Ref: Core and Builtins<35>-Footnote-1053338238
Ref: Core and Builtins<35>-Footnote-1063338296
Ref: Core and Builtins<35>-Footnote-1073338353
Ref: Core and Builtins<35>-Footnote-1083338410
Ref: Core and Builtins<35>-Footnote-1093338468
Ref: Core and Builtins<35>-Footnote-1103338526
Ref: Core and Builtins<35>-Footnote-1113338584
Ref: Core and Builtins<35>-Footnote-1123338642
Ref: Core and Builtins<35>-Footnote-1133338700
Ref: Core and Builtins<35>-Footnote-1143338758
Ref: Core and Builtins<35>-Footnote-1153338816
Ref: Core and Builtins<35>-Footnote-1163338874
Ref: Core and Builtins<35>-Footnote-1173338932
Ref: Core and Builtins<35>-Footnote-1183338990
Ref: Core and Builtins<35>-Footnote-1193339048
Ref: Core and Builtins<35>-Footnote-1203339106
Ref: Core and Builtins<35>-Footnote-1213339163
Ref: Core and Builtins<35>-Footnote-1223339221
Ref: Core and Builtins<35>-Footnote-1233339279
Ref: Core and Builtins<35>-Footnote-1243339336
Ref: Core and Builtins<35>-Footnote-1253339394
Ref: Core and Builtins<35>-Footnote-1263339452
Ref: Core and Builtins<35>-Footnote-1273339510
Ref: Core and Builtins<35>-Footnote-1283339568
Ref: Core and Builtins<35>-Footnote-1293339626
Ref: Core and Builtins<35>-Footnote-1303339684
Ref: Core and Builtins<35>-Footnote-1313339742
Ref: Core and Builtins<35>-Footnote-1323339800
Ref: Core and Builtins<35>-Footnote-1333339858
Ref: Core and Builtins<35>-Footnote-1343339916
Ref: Core and Builtins<35>-Footnote-1353339974
Ref: Core and Builtins<35>-Footnote-1363340032
Ref: Core and Builtins<35>-Footnote-1373340090
Ref: Core and Builtins<35>-Footnote-1383340148
Ref: Core and Builtins<35>-Footnote-1393340206
Ref: Core and Builtins<35>-Footnote-1403340264
Ref: Core and Builtins<35>-Footnote-1413340322
Ref: Core and Builtins<35>-Footnote-1423340380
Ref: Core and Builtins<35>-Footnote-1433340438
Ref: Core and Builtins<35>-Footnote-1443340496
Ref: Core and Builtins<35>-Footnote-1453340553
Ref: Core and Builtins<35>-Footnote-1463340611
Ref: Core and Builtins<35>-Footnote-1473340669
Ref: Core and Builtins<35>-Footnote-1483340726
Ref: Core and Builtins<35>-Footnote-1493340784
Ref: Core and Builtins<35>-Footnote-1503340842
Ref: Core and Builtins<35>-Footnote-1513340900
Ref: Core and Builtins<35>-Footnote-1523340958
Ref: Core and Builtins<35>-Footnote-1533341016
Ref: Core and Builtins<35>-Footnote-1543341074
Ref: Core and Builtins<35>-Footnote-1553341132
Ref: Core and Builtins<35>-Footnote-1563341190
Ref: Core and Builtins<35>-Footnote-1573341248
Ref: Core and Builtins<35>-Footnote-1583341306
Ref: Core and Builtins<35>-Footnote-1593341364
Ref: Core and Builtins<35>-Footnote-1603341422
Ref: Core and Builtins<35>-Footnote-1613341480
Ref: Core and Builtins<35>-Footnote-1623341538
Ref: Core and Builtins<35>-Footnote-1633341596
Ref: Core and Builtins<35>-Footnote-1643341654
Ref: Core and Builtins<35>-Footnote-1653341712
Ref: Core and Builtins<35>-Footnote-1663341770
Ref: Core and Builtins<35>-Footnote-1673341828
Ref: Core and Builtins<35>-Footnote-1683341885
Ref: Core and Builtins<35>-Footnote-1693341942
Ref: Core and Builtins<35>-Footnote-1703341999
Ref: Core and Builtins<35>-Footnote-1713342057
Node: Library<39>3342114
Ref: whatsnew/changelog id2153342239
Ref: 18053342239
Ref: Library<39>-Footnote-13390604
Ref: Library<39>-Footnote-23390660
Ref: Library<39>-Footnote-33390716
Ref: Library<39>-Footnote-43390772
Ref: Library<39>-Footnote-53390827
Ref: Library<39>-Footnote-63390883
Ref: Library<39>-Footnote-73390939
Ref: Library<39>-Footnote-83390995
Ref: Library<39>-Footnote-93391050
Ref: Library<39>-Footnote-103391106
Ref: Library<39>-Footnote-113391162
Ref: Library<39>-Footnote-123391219
Ref: Library<39>-Footnote-133391276
Ref: Library<39>-Footnote-143391333
Ref: Library<39>-Footnote-153391390
Ref: Library<39>-Footnote-163391447
Ref: Library<39>-Footnote-173391504
Ref: Library<39>-Footnote-183391561
Ref: Library<39>-Footnote-193391618
Ref: Library<39>-Footnote-203391675
Ref: Library<39>-Footnote-213391732
Ref: Library<39>-Footnote-223391789
Ref: Library<39>-Footnote-233391846
Ref: Library<39>-Footnote-243391903
Ref: Library<39>-Footnote-253391946
Ref: Library<39>-Footnote-263392002
Ref: Library<39>-Footnote-273392059
Ref: Library<39>-Footnote-283392116
Ref: Library<39>-Footnote-293392173
Ref: Library<39>-Footnote-303392230
Ref: Library<39>-Footnote-313392287
Ref: Library<39>-Footnote-323392344
Ref: Library<39>-Footnote-333392401
Ref: Library<39>-Footnote-343392458
Ref: Library<39>-Footnote-353392515
Ref: Library<39>-Footnote-363392572
Ref: Library<39>-Footnote-373392629
Ref: Library<39>-Footnote-383392685
Ref: Library<39>-Footnote-393392742
Ref: Library<39>-Footnote-403392799
Ref: Library<39>-Footnote-413392856
Ref: Library<39>-Footnote-423392913
Ref: Library<39>-Footnote-433392970
Ref: Library<39>-Footnote-443393027
Ref: Library<39>-Footnote-453393084
Ref: Library<39>-Footnote-463393141
Ref: Library<39>-Footnote-473393198
Ref: Library<39>-Footnote-483393255
Ref: Library<39>-Footnote-493393312
Ref: Library<39>-Footnote-503393369
Ref: Library<39>-Footnote-513393425
Ref: Library<39>-Footnote-523393482
Ref: Library<39>-Footnote-533393538
Ref: Library<39>-Footnote-543393595
Ref: Library<39>-Footnote-553393652
Ref: Library<39>-Footnote-563393709
Ref: Library<39>-Footnote-573393766
Ref: Library<39>-Footnote-583393823
Ref: Library<39>-Footnote-593393880
Ref: Library<39>-Footnote-603393937
Ref: Library<39>-Footnote-613393994
Ref: Library<39>-Footnote-623394051
Ref: Library<39>-Footnote-633394108
Ref: Library<39>-Footnote-643394165
Ref: Library<39>-Footnote-653394222
Ref: Library<39>-Footnote-663394279
Ref: Library<39>-Footnote-673394336
Ref: Library<39>-Footnote-683394393
Ref: Library<39>-Footnote-693394450
Ref: Library<39>-Footnote-703394506
Ref: Library<39>-Footnote-713394563
Ref: Library<39>-Footnote-723394620
Ref: Library<39>-Footnote-733394677
Ref: Library<39>-Footnote-743394734
Ref: Library<39>-Footnote-753394791
Ref: Library<39>-Footnote-763394847
Ref: Library<39>-Footnote-773394904
Ref: Library<39>-Footnote-783394961
Ref: Library<39>-Footnote-793395018
Ref: Library<39>-Footnote-803395075
Ref: Library<39>-Footnote-813395132
Ref: Library<39>-Footnote-823395189
Ref: Library<39>-Footnote-833395246
Ref: Library<39>-Footnote-843395302
Ref: Library<39>-Footnote-853395358
Ref: Library<39>-Footnote-863395414
Ref: Library<39>-Footnote-873395470
Ref: Library<39>-Footnote-883395527
Ref: Library<39>-Footnote-893395584
Ref: Library<39>-Footnote-903395641
Ref: Library<39>-Footnote-913395698
Ref: Library<39>-Footnote-923395755
Ref: Library<39>-Footnote-933395811
Ref: Library<39>-Footnote-943395868
Ref: Library<39>-Footnote-953395925
Ref: Library<39>-Footnote-963395982
Ref: Library<39>-Footnote-973396038
Ref: Library<39>-Footnote-983396095
Ref: Library<39>-Footnote-993396152
Ref: Library<39>-Footnote-1003396209
Ref: Library<39>-Footnote-1013396267
Ref: Library<39>-Footnote-1023396325
Ref: Library<39>-Footnote-1033396383
Ref: Library<39>-Footnote-1043396441
Ref: Library<39>-Footnote-1053396499
Ref: Library<39>-Footnote-1063396557
Ref: Library<39>-Footnote-1073396615
Ref: Library<39>-Footnote-1083396672
Ref: Library<39>-Footnote-1093396730
Ref: Library<39>-Footnote-1103396787
Ref: Library<39>-Footnote-1113396845
Ref: Library<39>-Footnote-1123396902
Ref: Library<39>-Footnote-1133396959
Ref: Library<39>-Footnote-1143397016
Ref: Library<39>-Footnote-1153397074
Ref: Library<39>-Footnote-1163397132
Ref: Library<39>-Footnote-1173397190
Ref: Library<39>-Footnote-1183397248
Ref: Library<39>-Footnote-1193397306
Ref: Library<39>-Footnote-1203397364
Ref: Library<39>-Footnote-1213397422
Ref: Library<39>-Footnote-1223397480
Ref: Library<39>-Footnote-1233397538
Ref: Library<39>-Footnote-1243397596
Ref: Library<39>-Footnote-1253397654
Ref: Library<39>-Footnote-1263397712
Ref: Library<39>-Footnote-1273397770
Ref: Library<39>-Footnote-1283397828
Ref: Library<39>-Footnote-1293397886
Ref: Library<39>-Footnote-1303397944
Ref: Library<39>-Footnote-1313398002
Ref: Library<39>-Footnote-1323398060
Ref: Library<39>-Footnote-1333398118
Ref: Library<39>-Footnote-1343398176
Ref: Library<39>-Footnote-1353398234
Ref: Library<39>-Footnote-1363398291
Ref: Library<39>-Footnote-1373398349
Ref: Library<39>-Footnote-1383398407
Ref: Library<39>-Footnote-1393398465
Ref: Library<39>-Footnote-1403398523
Ref: Library<39>-Footnote-1413398581
Ref: Library<39>-Footnote-1423398639
Ref: Library<39>-Footnote-1433398697
Ref: Library<39>-Footnote-1443398755
Ref: Library<39>-Footnote-1453398813
Ref: Library<39>-Footnote-1463398871
Ref: Library<39>-Footnote-1473398929
Ref: Library<39>-Footnote-1483398987
Ref: Library<39>-Footnote-1493399045
Ref: Library<39>-Footnote-1503399102
Ref: Library<39>-Footnote-1513399160
Ref: Library<39>-Footnote-1523399217
Ref: Library<39>-Footnote-1533399275
Ref: Library<39>-Footnote-1543399333
Ref: Library<39>-Footnote-1553399391
Ref: Library<39>-Footnote-1563399449
Ref: Library<39>-Footnote-1573399507
Ref: Library<39>-Footnote-1583399565
Ref: Library<39>-Footnote-1593399623
Ref: Library<39>-Footnote-1603399681
Ref: Library<39>-Footnote-1613399739
Ref: Library<39>-Footnote-1623399797
Ref: Library<39>-Footnote-1633399855
Ref: Library<39>-Footnote-1643399913
Ref: Library<39>-Footnote-1653399971
Ref: Library<39>-Footnote-1663400029
Ref: Library<39>-Footnote-1673400086
Ref: Library<39>-Footnote-1683400143
Ref: Library<39>-Footnote-1693400201
Ref: Library<39>-Footnote-1703400259
Ref: Library<39>-Footnote-1713400317
Ref: Library<39>-Footnote-1723400375
Ref: Library<39>-Footnote-1733400419
Ref: Library<39>-Footnote-1743400477
Ref: Library<39>-Footnote-1753400535
Ref: Library<39>-Footnote-1763400593
Ref: Library<39>-Footnote-1773400651
Ref: Library<39>-Footnote-1783400709
Ref: Library<39>-Footnote-1793400767
Ref: Library<39>-Footnote-1803400825
Ref: Library<39>-Footnote-1813400883
Ref: Library<39>-Footnote-1823400941
Ref: Library<39>-Footnote-1833400999
Ref: Library<39>-Footnote-1843401057
Ref: Library<39>-Footnote-1853401115
Ref: Library<39>-Footnote-1863401173
Ref: Library<39>-Footnote-1873401231
Ref: Library<39>-Footnote-1883401289
Ref: Library<39>-Footnote-1893401347
Ref: Library<39>-Footnote-1903401405
Ref: Library<39>-Footnote-1913401463
Ref: Library<39>-Footnote-1923401521
Ref: Library<39>-Footnote-1933401579
Ref: Library<39>-Footnote-1943401637
Ref: Library<39>-Footnote-1953401695
Ref: Library<39>-Footnote-1963401753
Ref: Library<39>-Footnote-1973401811
Ref: Library<39>-Footnote-1983401868
Ref: Library<39>-Footnote-1993401926
Ref: Library<39>-Footnote-2003401984
Ref: Library<39>-Footnote-2013402042
Ref: Library<39>-Footnote-2023402100
Ref: Library<39>-Footnote-2033402158
Ref: Library<39>-Footnote-2043402216
Ref: Library<39>-Footnote-2053402274
Ref: Library<39>-Footnote-2063402331
Ref: Library<39>-Footnote-2073402389
Ref: Library<39>-Footnote-2083402447
Ref: Library<39>-Footnote-2093402505
Ref: Library<39>-Footnote-2103402563
Ref: Library<39>-Footnote-2113402620
Ref: Library<39>-Footnote-2123402678
Ref: Library<39>-Footnote-2133402736
Ref: Library<39>-Footnote-2143402794
Ref: Library<39>-Footnote-2153402852
Ref: Library<39>-Footnote-2163402910
Ref: Library<39>-Footnote-2173402968
Ref: Library<39>-Footnote-2183403026
Ref: Library<39>-Footnote-2193403070
Ref: Library<39>-Footnote-2203403128
Ref: Library<39>-Footnote-2213403172
Ref: Library<39>-Footnote-2223403230
Ref: Library<39>-Footnote-2233403274
Ref: Library<39>-Footnote-2243403332
Ref: Library<39>-Footnote-2253403376
Ref: Library<39>-Footnote-2263403434
Ref: Library<39>-Footnote-2273403478
Ref: Library<39>-Footnote-2283403536
Ref: Library<39>-Footnote-2293403580
Ref: Library<39>-Footnote-2303403638
Ref: Library<39>-Footnote-2313403696
Ref: Library<39>-Footnote-2323403740
Ref: Library<39>-Footnote-2333403798
Ref: Library<39>-Footnote-2343403842
Ref: Library<39>-Footnote-2353403900
Ref: Library<39>-Footnote-2363403958
Ref: Library<39>-Footnote-2373404016
Ref: Library<39>-Footnote-2383404074
Ref: Library<39>-Footnote-2393404118
Ref: Library<39>-Footnote-2403404176
Ref: Library<39>-Footnote-2413404220
Ref: Library<39>-Footnote-2423404267
Ref: Library<39>-Footnote-2433404324
Ref: Library<39>-Footnote-2443404382
Ref: Library<39>-Footnote-2453404426
Ref: Library<39>-Footnote-2463404484
Ref: Library<39>-Footnote-2473404528
Ref: Library<39>-Footnote-2483404586
Ref: Library<39>-Footnote-2493404630
Ref: Library<39>-Footnote-2503404688
Ref: Library<39>-Footnote-2513404732
Ref: Library<39>-Footnote-2523404790
Ref: Library<39>-Footnote-2533404834
Ref: Library<39>-Footnote-2543404892
Ref: Library<39>-Footnote-2553404950
Ref: Library<39>-Footnote-2563405008
Ref: Library<39>-Footnote-2573405066
Ref: Library<39>-Footnote-2583405123
Ref: Library<39>-Footnote-2593405181
Ref: Library<39>-Footnote-2603405225
Ref: Library<39>-Footnote-2613405283
Ref: Library<39>-Footnote-2623405341
Ref: Library<39>-Footnote-2633405399
Ref: Library<39>-Footnote-2643405457
Ref: Library<39>-Footnote-2653405501
Ref: Library<39>-Footnote-2663405559
Ref: Library<39>-Footnote-2673405603
Ref: Library<39>-Footnote-2683405661
Ref: Library<39>-Footnote-2693405705
Ref: Library<39>-Footnote-2703405763
Ref: Library<39>-Footnote-2713405807
Ref: Library<39>-Footnote-2723405865
Ref: Library<39>-Footnote-2733405922
Ref: Library<39>-Footnote-2743405980
Ref: Library<39>-Footnote-2753406038
Ref: Library<39>-Footnote-2763406096
Ref: Library<39>-Footnote-2773406154
Ref: Library<39>-Footnote-2783406212
Ref: Library<39>-Footnote-2793406270
Ref: Library<39>-Footnote-2803406328
Ref: Library<39>-Footnote-2813406386
Ref: Library<39>-Footnote-2823406444
Ref: Library<39>-Footnote-2833406502
Ref: Library<39>-Footnote-2843406559
Ref: Library<39>-Footnote-2853406617
Ref: Library<39>-Footnote-2863406675
Ref: Library<39>-Footnote-2873406733
Ref: Library<39>-Footnote-2883406790
Ref: Library<39>-Footnote-2893406848
Ref: Library<39>-Footnote-2903406905
Ref: Library<39>-Footnote-2913406962
Ref: Library<39>-Footnote-2923407019
Ref: Library<39>-Footnote-2933407076
Ref: Library<39>-Footnote-2943407133
Ref: Library<39>-Footnote-2953407190
Ref: Library<39>-Footnote-2963407247
Ref: Library<39>-Footnote-2973407314
Ref: Library<39>-Footnote-2983407375
Ref: Library<39>-Footnote-2993407442
Ref: Library<39>-Footnote-3003407486
Ref: Library<39>-Footnote-3013407553
Ref: Library<39>-Footnote-3023407620
Ref: Library<39>-Footnote-3033407687
Ref: Library<39>-Footnote-3043407754
Node: Documentation<18>3407821
Ref: whatsnew/changelog id2163407934
Ref: 18193407934
Ref: Documentation<18>-Footnote-13409886
Ref: Documentation<18>-Footnote-23409942
Ref: Documentation<18>-Footnote-33409998
Ref: Documentation<18>-Footnote-43410054
Ref: Documentation<18>-Footnote-53410110
Ref: Documentation<18>-Footnote-63410166
Ref: Documentation<18>-Footnote-73410222
Ref: Documentation<18>-Footnote-83410278
Ref: Documentation<18>-Footnote-93410334
Ref: Documentation<18>-Footnote-103410389
Ref: Documentation<18>-Footnote-113410445
Ref: Documentation<18>-Footnote-123410502
Ref: Documentation<18>-Footnote-133410558
Ref: Documentation<18>-Footnote-143410615
Node: Tests<21>3410672
Ref: whatsnew/changelog id2173410783
Ref: 181a3410783
Ref: Tests<21>-Footnote-13423958
Ref: Tests<21>-Footnote-23424014
Ref: Tests<21>-Footnote-33424070
Ref: Tests<21>-Footnote-43424126
Ref: Tests<21>-Footnote-53424182
Ref: Tests<21>-Footnote-63424237
Ref: Tests<21>-Footnote-73424293
Ref: Tests<21>-Footnote-83424349
Ref: Tests<21>-Footnote-93424405
Ref: Tests<21>-Footnote-103424461
Ref: Tests<21>-Footnote-113424518
Ref: Tests<21>-Footnote-123424575
Ref: Tests<21>-Footnote-133424632
Ref: Tests<21>-Footnote-143424689
Ref: Tests<21>-Footnote-153424746
Ref: Tests<21>-Footnote-163424803
Ref: Tests<21>-Footnote-173424860
Ref: Tests<21>-Footnote-183424917
Ref: Tests<21>-Footnote-193424974
Ref: Tests<21>-Footnote-203425031
Ref: Tests<21>-Footnote-213425088
Ref: Tests<21>-Footnote-223425145
Ref: Tests<21>-Footnote-233425202
Ref: Tests<21>-Footnote-243425259
Ref: Tests<21>-Footnote-253425316
Ref: Tests<21>-Footnote-263425373
Ref: Tests<21>-Footnote-273425430
Ref: Tests<21>-Footnote-283425487
Ref: Tests<21>-Footnote-293425544
Ref: Tests<21>-Footnote-303425601
Ref: Tests<21>-Footnote-313425658
Ref: Tests<21>-Footnote-323425715
Ref: Tests<21>-Footnote-333425772
Ref: Tests<21>-Footnote-343425816
Ref: Tests<21>-Footnote-353425872
Ref: Tests<21>-Footnote-363425929
Ref: Tests<21>-Footnote-373425985
Ref: Tests<21>-Footnote-383426041
Ref: Tests<21>-Footnote-393426098
Ref: Tests<21>-Footnote-403426155
Ref: Tests<21>-Footnote-413426212
Ref: Tests<21>-Footnote-423426269
Ref: Tests<21>-Footnote-433426326
Ref: Tests<21>-Footnote-443426383
Ref: Tests<21>-Footnote-453426440
Ref: Tests<21>-Footnote-463426497
Ref: Tests<21>-Footnote-473426554
Ref: Tests<21>-Footnote-483426611
Ref: Tests<21>-Footnote-493426668
Ref: Tests<21>-Footnote-503426725
Ref: Tests<21>-Footnote-513426782
Ref: Tests<21>-Footnote-523426839
Ref: Tests<21>-Footnote-533426896
Ref: Tests<21>-Footnote-543426953
Ref: Tests<21>-Footnote-553427010
Ref: Tests<21>-Footnote-563427067
Ref: Tests<21>-Footnote-573427124
Ref: Tests<21>-Footnote-583427180
Ref: Tests<21>-Footnote-593427237
Node: Build<21>3427293
Ref: whatsnew/changelog id2183427398
Ref: 181c3427398
Ref: Build<21>-Footnote-13431405
Ref: Build<21>-Footnote-23431461
Ref: Build<21>-Footnote-33431517
Ref: Build<21>-Footnote-43431573
Ref: Build<21>-Footnote-53431629
Ref: Build<21>-Footnote-63431685
Ref: Build<21>-Footnote-73431741
Ref: Build<21>-Footnote-83431796
Ref: Build<21>-Footnote-93431852
Ref: Build<21>-Footnote-103431908
Ref: Build<21>-Footnote-113431964
Ref: Build<21>-Footnote-123432021
Ref: Build<21>-Footnote-133432078
Ref: Build<21>-Footnote-143432135
Ref: Build<21>-Footnote-153432192
Ref: Build<21>-Footnote-163432248
Ref: Build<21>-Footnote-173432305
Ref: Build<21>-Footnote-183432362
Ref: Build<21>-Footnote-193432419
Ref: Build<21>-Footnote-203432476
Ref: Build<21>-Footnote-213432532
Ref: Build<21>-Footnote-223432589
Ref: Build<21>-Footnote-233432645
Ref: Build<21>-Footnote-243432702
Node: Windows<19>3432759
Ref: whatsnew/changelog id2193432864
Ref: 181e3432864
Ref: Windows<19>-Footnote-13435376
Ref: Windows<19>-Footnote-23435432
Ref: Windows<19>-Footnote-33435488
Ref: Windows<19>-Footnote-43435543
Ref: Windows<19>-Footnote-53435599
Ref: Windows<19>-Footnote-63435655
Ref: Windows<19>-Footnote-73435710
Ref: Windows<19>-Footnote-83435766
Ref: Windows<19>-Footnote-93435822
Ref: Windows<19>-Footnote-103435878
Ref: Windows<19>-Footnote-113435935
Ref: Windows<19>-Footnote-123435991
Ref: Windows<19>-Footnote-133436048
Node: macOS<14>3436105
Ref: whatsnew/changelog id2203436209
Ref: 181f3436209
Ref: macOS<14>-Footnote-13436473
Ref: macOS<14>-Footnote-23436529
Ref: macOS<14>-Footnote-33436585
Node: IDLE<17>3436640
Ref: whatsnew/changelog id2213436748
Ref: 18203436748
Ref: IDLE<17>-Footnote-13436939
Node: Tools/Demos<12>3436995
Ref: whatsnew/changelog id2223437103
Ref: 18213437103
Ref: Tools/Demos<12>-Footnote-13439630
Ref: Tools/Demos<12>-Footnote-23439686
Ref: Tools/Demos<12>-Footnote-33439742
Ref: Tools/Demos<12>-Footnote-43439804
Ref: Tools/Demos<12>-Footnote-53439893
Ref: Tools/Demos<12>-Footnote-63439949
Ref: Tools/Demos<12>-Footnote-73440043
Ref: Tools/Demos<12>-Footnote-83440099
Ref: Tools/Demos<12>-Footnote-93440155
Ref: Tools/Demos<12>-Footnote-103440210
Ref: Tools/Demos<12>-Footnote-113440306
Ref: Tools/Demos<12>-Footnote-123440363
Ref: Tools/Demos<12>-Footnote-133440420
Ref: Tools/Demos<12>-Footnote-143440477
Ref: Tools/Demos<12>-Footnote-153440534
Ref: Tools/Demos<12>-Footnote-163440591
Ref: Tools/Demos<12>-Footnote-173440648
Ref: Tools/Demos<12>-Footnote-183440704
Node: C API<21>3440802
Ref: whatsnew/changelog id2233440893
Ref: 18223440893
Ref: C API<21>-Footnote-13455826
Ref: C API<21>-Footnote-23455881
Ref: C API<21>-Footnote-33455937
Ref: C API<21>-Footnote-43455993
Ref: C API<21>-Footnote-53456049
Ref: C API<21>-Footnote-63456105
Ref: C API<21>-Footnote-73456161
Ref: C API<21>-Footnote-83456216
Ref: C API<21>-Footnote-93456272
Ref: C API<21>-Footnote-103456328
Ref: C API<21>-Footnote-113456385
Ref: C API<21>-Footnote-123456442
Ref: C API<21>-Footnote-133456499
Ref: C API<21>-Footnote-143456556
Ref: C API<21>-Footnote-153456613
Ref: C API<21>-Footnote-163456670
Ref: C API<21>-Footnote-173456727
Ref: C API<21>-Footnote-183456784
Ref: C API<21>-Footnote-193456841
Ref: C API<21>-Footnote-203456898
Ref: C API<21>-Footnote-213456955
Ref: C API<21>-Footnote-223457012
Ref: C API<21>-Footnote-233457069
Ref: C API<21>-Footnote-243457126
Ref: C API<21>-Footnote-253457183
Ref: C API<21>-Footnote-263457240
Ref: C API<21>-Footnote-273457297
Ref: C API<21>-Footnote-283457354
Ref: C API<21>-Footnote-293457411
Ref: C API<21>-Footnote-303457468
Ref: C API<21>-Footnote-313457525
Ref: C API<21>-Footnote-323457582
Ref: C API<21>-Footnote-333457625
Ref: C API<21>-Footnote-343457682
Ref: C API<21>-Footnote-353457739
Ref: C API<21>-Footnote-363457796
Ref: C API<21>-Footnote-373457853
Ref: C API<21>-Footnote-383457910
Ref: C API<21>-Footnote-393457967
Ref: C API<21>-Footnote-403458024
Ref: C API<21>-Footnote-413458081
Ref: C API<21>-Footnote-423458138
Ref: C API<21>-Footnote-433458195
Ref: C API<21>-Footnote-443458252
Ref: C API<21>-Footnote-453458309
Ref: C API<21>-Footnote-463458366
Ref: C API<21>-Footnote-473458423
Ref: C API<21>-Footnote-483458480
Ref: C API<21>-Footnote-493458537
Ref: C API<21>-Footnote-503458593
Ref: C API<21>-Footnote-513458650
Ref: C API<21>-Footnote-523458707
Ref: C API<21>-Footnote-533458764
Ref: C API<21>-Footnote-543458821
Ref: C API<21>-Footnote-553458878
Ref: C API<21>-Footnote-563458935
Ref: C API<21>-Footnote-573458992
Ref: C API<21>-Footnote-583459049
Ref: C API<21>-Footnote-593459115
Node: Python 3 12 0 beta 13459181
Ref: whatsnew/changelog python-3-12-0-beta-13459307
Ref: 182d3459307
Node: Security<19>3459848
Ref: whatsnew/changelog id2243459937
Ref: 182e3459937
Ref: Security<19>-Footnote-13460756
Ref: Security<19>-Footnote-23460811
Ref: Security<19>-Footnote-33460867
Ref: Security<19>-Footnote-43460922
Ref: Security<19>-Footnote-53460978
Node: Library<40>3461034
Ref: whatsnew/changelog id2253461153
Ref: 182f3461153
Ref: Library<40>-Footnote-13461369
Node: Core and Builtins<36>3461425
Ref: whatsnew/changelog id2263461543
Ref: 18303461543
Ref: Core and Builtins<36>-Footnote-13467973
Ref: Core and Builtins<36>-Footnote-23468029
Ref: Core and Builtins<36>-Footnote-33468085
Ref: Core and Builtins<36>-Footnote-43468127
Ref: Core and Builtins<36>-Footnote-53468183
Ref: Core and Builtins<36>-Footnote-63468239
Ref: Core and Builtins<36>-Footnote-73468295
Ref: Core and Builtins<36>-Footnote-83468337
Ref: Core and Builtins<36>-Footnote-93468393
Ref: Core and Builtins<36>-Footnote-103468449
Ref: Core and Builtins<36>-Footnote-113468505
Ref: Core and Builtins<36>-Footnote-123468561
Ref: Core and Builtins<36>-Footnote-133468618
Ref: Core and Builtins<36>-Footnote-143468675
Ref: Core and Builtins<36>-Footnote-153468718
Ref: Core and Builtins<36>-Footnote-163468775
Ref: Core and Builtins<36>-Footnote-173468832
Ref: Core and Builtins<36>-Footnote-183468889
Ref: Core and Builtins<36>-Footnote-193468946
Ref: Core and Builtins<36>-Footnote-203469003
Ref: Core and Builtins<36>-Footnote-213469060
Ref: Core and Builtins<36>-Footnote-223469117
Ref: Core and Builtins<36>-Footnote-233469174
Ref: Core and Builtins<36>-Footnote-243469231
Ref: Core and Builtins<36>-Footnote-253469288
Node: Library<41>3469331
Ref: whatsnew/changelog id2273469459
Ref: 18313469459
Ref: Library<41>-Footnote-13469882
Ref: Library<41>-Footnote-23469938
Node: Core and Builtins<37>3469994
Ref: whatsnew/changelog id2283470112
Ref: 18323470112
Ref: Core and Builtins<37>-Footnote-13472460
Ref: Core and Builtins<37>-Footnote-23472516
Ref: Core and Builtins<37>-Footnote-33472572
Ref: Core and Builtins<37>-Footnote-43472628
Ref: Core and Builtins<37>-Footnote-53472684
Ref: Core and Builtins<37>-Footnote-63472740
Ref: Core and Builtins<37>-Footnote-73472796
Ref: Core and Builtins<37>-Footnote-83472852
Ref: Core and Builtins<37>-Footnote-93472907
Ref: Core and Builtins<37>-Footnote-103472963
Ref: Core and Builtins<37>-Footnote-113473019
Ref: Core and Builtins<37>-Footnote-123473075
Ref: Core and Builtins<37>-Footnote-133473118
Node: Library<42>3473175
Ref: whatsnew/changelog id2293473303
Ref: 18333473303
Ref: Library<42>-Footnote-13473504
Node: Core and Builtins<38>3473560
Ref: whatsnew/changelog id2303473678
Ref: 18343473678
Ref: Core and Builtins<38>-Footnote-13475328
Ref: Core and Builtins<38>-Footnote-23475384
Ref: Core and Builtins<38>-Footnote-33475439
Ref: Core and Builtins<38>-Footnote-43475495
Ref: Core and Builtins<38>-Footnote-53475551
Ref: Core and Builtins<38>-Footnote-63475593
Ref: Core and Builtins<38>-Footnote-73475648
Ref: Core and Builtins<38>-Footnote-83475704
Ref: Core and Builtins<38>-Footnote-93475746
Ref: Core and Builtins<38>-Footnote-103475801
Ref: Core and Builtins<38>-Footnote-113475844
Ref: Core and Builtins<38>-Footnote-123475900
Ref: Core and Builtins<38>-Footnote-133475956
Node: Library<43>3476022
Ref: whatsnew/changelog id2313476146
Ref: 18353476146
Ref: Library<43>-Footnote-13499797
Ref: Library<43>-Footnote-23499862
Ref: Library<43>-Footnote-33499918
Ref: Library<43>-Footnote-43499960
Ref: Library<43>-Footnote-53500016
Ref: Library<43>-Footnote-63500072
Ref: Library<43>-Footnote-73500128
Ref: Library<43>-Footnote-83500184
Ref: Library<43>-Footnote-93500239
Ref: Library<43>-Footnote-103500295
Ref: Library<43>-Footnote-113500352
Ref: Library<43>-Footnote-123500409
Ref: Library<43>-Footnote-133500466
Ref: Library<43>-Footnote-143500523
Ref: Library<43>-Footnote-153500580
Ref: Library<43>-Footnote-163500637
Ref: Library<43>-Footnote-173500694
Ref: Library<43>-Footnote-183500770
Ref: Library<43>-Footnote-193500827
Ref: Library<43>-Footnote-203500884
Ref: Library<43>-Footnote-213500940
Ref: Library<43>-Footnote-223500997
Ref: Library<43>-Footnote-233501063
Ref: Library<43>-Footnote-243501120
Ref: Library<43>-Footnote-253501176
Ref: Library<43>-Footnote-263501232
Ref: Library<43>-Footnote-273501289
Ref: Library<43>-Footnote-283501346
Ref: Library<43>-Footnote-293501403
Ref: Library<43>-Footnote-303501460
Ref: Library<43>-Footnote-313501517
Ref: Library<43>-Footnote-323501574
Ref: Library<43>-Footnote-333501631
Ref: Library<43>-Footnote-343501674
Ref: Library<43>-Footnote-353501731
Ref: Library<43>-Footnote-363501788
Ref: Library<43>-Footnote-373501845
Ref: Library<43>-Footnote-383501902
Ref: Library<43>-Footnote-393501958
Ref: Library<43>-Footnote-403502015
Ref: Library<43>-Footnote-413502071
Ref: Library<43>-Footnote-423502128
Ref: Library<43>-Footnote-433502185
Ref: Library<43>-Footnote-443502242
Ref: Library<43>-Footnote-453502299
Ref: Library<43>-Footnote-463502356
Ref: Library<43>-Footnote-473502413
Ref: Library<43>-Footnote-483502469
Ref: Library<43>-Footnote-493502525
Ref: Library<43>-Footnote-503502582
Ref: Library<43>-Footnote-513502639
Ref: Library<43>-Footnote-523502696
Ref: Library<43>-Footnote-533502753
Ref: Library<43>-Footnote-543502809
Ref: Library<43>-Footnote-553502866
Ref: Library<43>-Footnote-563502922
Ref: Library<43>-Footnote-573502979
Ref: Library<43>-Footnote-583503036
Ref: Library<43>-Footnote-593503092
Ref: Library<43>-Footnote-603503148
Ref: Library<43>-Footnote-613503205
Ref: Library<43>-Footnote-623503262
Ref: Library<43>-Footnote-633503318
Ref: Library<43>-Footnote-643503375
Ref: Library<43>-Footnote-653503432
Ref: Library<43>-Footnote-663503489
Ref: Library<43>-Footnote-673503546
Ref: Library<43>-Footnote-683503603
Ref: Library<43>-Footnote-693503660
Ref: Library<43>-Footnote-703503717
Ref: Library<43>-Footnote-713503774
Ref: Library<43>-Footnote-723503831
Ref: Library<43>-Footnote-733503888
Ref: Library<43>-Footnote-743503945
Ref: Library<43>-Footnote-753504002
Ref: Library<43>-Footnote-763504059
Ref: Library<43>-Footnote-773504116
Ref: Library<43>-Footnote-783504173
Ref: Library<43>-Footnote-793504216
Ref: Library<43>-Footnote-803504273
Ref: Library<43>-Footnote-813504330
Ref: Library<43>-Footnote-823504373
Ref: Library<43>-Footnote-833504429
Ref: Library<43>-Footnote-843504485
Ref: Library<43>-Footnote-853504542
Ref: Library<43>-Footnote-863504599
Ref: Library<43>-Footnote-873504656
Ref: Library<43>-Footnote-883504713
Ref: Library<43>-Footnote-893504770
Ref: Library<43>-Footnote-903504813
Ref: Library<43>-Footnote-913504870
Ref: Library<43>-Footnote-923504913
Ref: Library<43>-Footnote-933504969
Ref: Library<43>-Footnote-943505026
Ref: Library<43>-Footnote-953505083
Ref: Library<43>-Footnote-963505126
Ref: Library<43>-Footnote-973505183
Ref: Library<43>-Footnote-983505240
Ref: Library<43>-Footnote-993505297
Ref: Library<43>-Footnote-1003505353
Ref: Library<43>-Footnote-1013505411
Ref: Library<43>-Footnote-1023505469
Ref: Library<43>-Footnote-1033505527
Ref: Library<43>-Footnote-1043505585
Ref: Library<43>-Footnote-1053505643
Ref: Library<43>-Footnote-1063505701
Ref: Library<43>-Footnote-1073505758
Ref: Library<43>-Footnote-1083505815
Ref: Library<43>-Footnote-1093505873
Ref: Library<43>-Footnote-1103505917
Ref: Library<43>-Footnote-1113505974
Ref: Library<43>-Footnote-1123506032
Ref: Library<43>-Footnote-1133506090
Ref: Library<43>-Footnote-1143506147
Ref: Library<43>-Footnote-1153506204
Ref: Library<43>-Footnote-1163506261
Ref: Library<43>-Footnote-1173506319
Ref: Library<43>-Footnote-1183506377
Ref: Library<43>-Footnote-1193506434
Ref: Library<43>-Footnote-1203506491
Ref: Library<43>-Footnote-1213506548
Ref: Library<43>-Footnote-1223506605
Ref: Library<43>-Footnote-1233506662
Ref: Library<43>-Footnote-1243506719
Ref: Library<43>-Footnote-1253506776
Ref: Library<43>-Footnote-1263506833
Ref: Library<43>-Footnote-1273506890
Ref: Library<43>-Footnote-1283506947
Ref: Library<43>-Footnote-1293507004
Ref: Library<43>-Footnote-1303507061
Ref: Library<43>-Footnote-1313507118
Ref: Library<43>-Footnote-1323507175
Ref: Library<43>-Footnote-1333507232
Ref: Library<43>-Footnote-1343507299
Ref: Library<43>-Footnote-1353507366
Ref: Library<43>-Footnote-1363507433
Ref: Library<43>-Footnote-1373507500
Ref: Library<43>-Footnote-1383507567
Ref: Library<43>-Footnote-1393507634
Ref: Library<43>-Footnote-1403507701
Node: Documentation<19>3507768
Ref: whatsnew/changelog id2323507880
Ref: 18403507880
Ref: Documentation<19>-Footnote-13508653
Ref: Documentation<19>-Footnote-23508708
Ref: Documentation<19>-Footnote-33508764
Ref: Documentation<19>-Footnote-43508806
Ref: Documentation<19>-Footnote-53508861
Ref: Documentation<19>-Footnote-63508916
Node: Tests<22>3508971
Ref: whatsnew/changelog id2333509081
Ref: 18413509081
Ref: Tests<22>-Footnote-13509998
Ref: Tests<22>-Footnote-23510054
Ref: Tests<22>-Footnote-33510110
Ref: Tests<22>-Footnote-43510165
Ref: Tests<22>-Footnote-53510221
Ref: Tests<22>-Footnote-63510277
Node: Build<22>3510332
Ref: whatsnew/changelog id2343510436
Ref: 18433510436
Ref: Build<22>-Footnote-13512022
Ref: Build<22>-Footnote-23512078
Ref: Build<22>-Footnote-33512133
Ref: Build<22>-Footnote-43512189
Ref: Build<22>-Footnote-53512245
Ref: Build<22>-Footnote-63512301
Ref: Build<22>-Footnote-73512356
Ref: Build<22>-Footnote-83512411
Ref: Build<22>-Footnote-93512467
Node: Windows<20>3512522
Ref: whatsnew/changelog id2353512626
Ref: 18443512626
Ref: Windows<20>-Footnote-13513481
Ref: Windows<20>-Footnote-23513537
Ref: Windows<20>-Footnote-33513592
Ref: Windows<20>-Footnote-43513648
Ref: Windows<20>-Footnote-53513704
Ref: Windows<20>-Footnote-63513760
Node: macOS<15>3513815
Ref: whatsnew/changelog id2363513918
Ref: 18453513918
Ref: macOS<15>-Footnote-13514722
Ref: macOS<15>-Footnote-23514777
Ref: macOS<15>-Footnote-33514833
Ref: macOS<15>-Footnote-43514889
Ref: macOS<15>-Footnote-53514945
Ref: macOS<15>-Footnote-63515000
Node: IDLE<18>3515056
Ref: whatsnew/changelog id2373515163
Ref: 18463515163
Ref: IDLE<18>-Footnote-13515447
Ref: IDLE<18>-Footnote-23515503
Ref: IDLE<18>-Footnote-33515559
Node: Tools/Demos<13>3515614
Ref: whatsnew/changelog id2383515721
Ref: 18473515721
Ref: Tools/Demos<13>-Footnote-13515981
Node: C API<22>3516037
Ref: whatsnew/changelog id2393516127
Ref: 18483516127
Ref: C API<22>-Footnote-13519111
Ref: C API<22>-Footnote-23519167
Ref: C API<22>-Footnote-33519223
Ref: C API<22>-Footnote-43519279
Ref: C API<22>-Footnote-53519335
Ref: C API<22>-Footnote-63519391
Ref: C API<22>-Footnote-73519447
Ref: C API<22>-Footnote-83519489
Ref: C API<22>-Footnote-93519545
Ref: C API<22>-Footnote-103519601
Ref: C API<22>-Footnote-113519657
Node: Python 3 12 0 alpha 73519713
Ref: whatsnew/changelog python-3-12-0-alpha-73519839
Ref: 184f3519839
Node: Core and Builtins<39>3520290
Ref: whatsnew/changelog id2403520389
Ref: 18503520389
Ref: Core and Builtins<39>-Footnote-13521723
Ref: Core and Builtins<39>-Footnote-23521779
Ref: Core and Builtins<39>-Footnote-33521834
Ref: Core and Builtins<39>-Footnote-43521890
Ref: Core and Builtins<39>-Footnote-53521946
Ref: Core and Builtins<39>-Footnote-63522002
Ref: Core and Builtins<39>-Footnote-73522058
Ref: Core and Builtins<39>-Footnote-83522114
Ref: Core and Builtins<39>-Footnote-93522170
Ref: Core and Builtins<39>-Footnote-103522226
Node: Library<44>3522282
Ref: whatsnew/changelog id2413522411
Ref: 18523522411
Ref: Library<44>-Footnote-13522718
Node: Core and Builtins<40>3522774
Ref: whatsnew/changelog id2423522891
Ref: 18533522891
Ref: Core and Builtins<40>-Footnote-13524213
Ref: Core and Builtins<40>-Footnote-23524269
Ref: Core and Builtins<40>-Footnote-33524325
Ref: Core and Builtins<40>-Footnote-43524381
Ref: Core and Builtins<40>-Footnote-53524423
Ref: Core and Builtins<40>-Footnote-63524479
Ref: Core and Builtins<40>-Footnote-73524535
Ref: Core and Builtins<40>-Footnote-83524591
Node: Build<23>3524647
Ref: whatsnew/changelog id2433524774
Ref: 18543524774
Ref: Build<23>-Footnote-13524954
Node: Core and Builtins<41>3525010
Ref: whatsnew/changelog id2443525127
Ref: 18553525127
Ref: Core and Builtins<41>-Footnote-13525327
Node: Library<45>3525383
Ref: whatsnew/changelog id2453525508
Ref: 18563525508
Ref: Library<45>-Footnote-13533447
Ref: Library<45>-Footnote-23533514
Ref: Library<45>-Footnote-33533556
Ref: Library<45>-Footnote-43533612
Ref: Library<45>-Footnote-53533668
Ref: Library<45>-Footnote-63533724
Ref: Library<45>-Footnote-73533780
Ref: Library<45>-Footnote-83533836
Ref: Library<45>-Footnote-93533892
Ref: Library<45>-Footnote-103533948
Ref: Library<45>-Footnote-113534005
Ref: Library<45>-Footnote-123534062
Ref: Library<45>-Footnote-133534119
Ref: Library<45>-Footnote-143534176
Ref: Library<45>-Footnote-153534233
Ref: Library<45>-Footnote-163534289
Ref: Library<45>-Footnote-173534345
Ref: Library<45>-Footnote-183534401
Ref: Library<45>-Footnote-193534458
Ref: Library<45>-Footnote-203534515
Ref: Library<45>-Footnote-213534572
Ref: Library<45>-Footnote-223534629
Ref: Library<45>-Footnote-233534686
Ref: Library<45>-Footnote-243534743
Ref: Library<45>-Footnote-253534799
Ref: Library<45>-Footnote-263534856
Ref: Library<45>-Footnote-273534912
Ref: Library<45>-Footnote-283534969
Ref: Library<45>-Footnote-293535026
Ref: Library<45>-Footnote-303535083
Ref: Library<45>-Footnote-313535139
Ref: Library<45>-Footnote-323535196
Ref: Library<45>-Footnote-333535253
Ref: Library<45>-Footnote-343535310
Ref: Library<45>-Footnote-353535366
Ref: Library<45>-Footnote-363535423
Ref: Library<45>-Footnote-373535479
Ref: Library<45>-Footnote-383535535
Ref: Library<45>-Footnote-393535591
Ref: Library<45>-Footnote-403535647
Ref: Library<45>-Footnote-413535703
Ref: Library<45>-Footnote-423535759
Ref: Library<45>-Footnote-433535815
Node: Documentation<20>3535881
Ref: whatsnew/changelog id2463535994
Ref: 185d3535994
Ref: Documentation<20>-Footnote-13536193
Node: Tests<23>3536249
Ref: whatsnew/changelog id2473536360
Ref: 185e3536360
Ref: Tests<23>-Footnote-13536717
Ref: Tests<23>-Footnote-23536773
Ref: Tests<23>-Footnote-33536829
Node: Build<24>3536885
Ref: whatsnew/changelog id2483536990
Ref: 185f3536990
Ref: Build<24>-Footnote-13537236
Ref: Build<24>-Footnote-23537292
Node: Windows<21>3537348
Ref: whatsnew/changelog id2493537459
Ref: 18603537459
Ref: Windows<21>-Footnote-13537759
Ref: Windows<21>-Footnote-23537815
Node: Tools/Demos<14>3537870
Ref: whatsnew/changelog id2503537981
Ref: 18613537981
Ref: Tools/Demos<14>-Footnote-13538116
Node: C API<23>3538172
Ref: whatsnew/changelog id2513538263
Ref: 18623538263
Ref: C API<23>-Footnote-13538481
Node: Python 3 12 0 alpha 63538537
Ref: whatsnew/changelog python-3-12-0-alpha-63538664
Ref: 18633538664
Node: Security<20>3538997
Ref: whatsnew/changelog id2523539097
Ref: 18643539097
Ref: Security<20>-Footnote-13540035
Ref: Security<20>-Footnote-23540090
Ref: Security<20>-Footnote-33540146
Ref: Security<20>-Footnote-43540201
Ref: Security<20>-Footnote-53540256
Ref: Security<20>-Footnote-63540311
Ref: Security<20>-Footnote-73540372
Ref: Security<20>-Footnote-83540427
Ref: Security<20>-Footnote-93540475
Node: Core and Builtins<42>3540531
Ref: whatsnew/changelog id2533540651
Ref: 18653540651
Ref: Core and Builtins<42>-Footnote-13544289
Ref: Core and Builtins<42>-Footnote-23544345
Ref: Core and Builtins<42>-Footnote-33544401
Ref: Core and Builtins<42>-Footnote-43544457
Ref: Core and Builtins<42>-Footnote-53544513
Ref: Core and Builtins<42>-Footnote-63544569
Ref: Core and Builtins<42>-Footnote-73544625
Ref: Core and Builtins<42>-Footnote-83544681
Ref: Core and Builtins<42>-Footnote-93544737
Ref: Core and Builtins<42>-Footnote-103544793
Ref: Core and Builtins<42>-Footnote-113544850
Ref: Core and Builtins<42>-Footnote-123544907
Ref: Core and Builtins<42>-Footnote-133544963
Ref: Core and Builtins<42>-Footnote-143545020
Ref: Core and Builtins<42>-Footnote-153545077
Ref: Core and Builtins<42>-Footnote-163545133
Ref: Core and Builtins<42>-Footnote-173545189
Ref: Core and Builtins<42>-Footnote-183545246
Ref: Core and Builtins<42>-Footnote-193545303
Ref: Core and Builtins<42>-Footnote-203545360
Ref: Core and Builtins<42>-Footnote-213545417
Ref: Core and Builtins<42>-Footnote-223545474
Node: Library<46>3545530
Ref: whatsnew/changelog id2543545655
Ref: 18683545655
Ref: Library<46>-Footnote-13551479
Ref: Library<46>-Footnote-23551535
Ref: Library<46>-Footnote-33551591
Ref: Library<46>-Footnote-43551646
Ref: Library<46>-Footnote-53551701
Ref: Library<46>-Footnote-63551757
Ref: Library<46>-Footnote-73551813
Ref: Library<46>-Footnote-83551869
Ref: Library<46>-Footnote-93551925
Ref: Library<46>-Footnote-103551992
Ref: Library<46>-Footnote-113552048
Ref: Library<46>-Footnote-123552132
Ref: Library<46>-Footnote-133552189
Ref: Library<46>-Footnote-143552245
Ref: Library<46>-Footnote-153552302
Ref: Library<46>-Footnote-163552358
Ref: Library<46>-Footnote-173552414
Ref: Library<46>-Footnote-183552471
Ref: Library<46>-Footnote-193552528
Ref: Library<46>-Footnote-203552585
Ref: Library<46>-Footnote-213552642
Ref: Library<46>-Footnote-223552699
Ref: Library<46>-Footnote-233552756
Ref: Library<46>-Footnote-243552813
Ref: Library<46>-Footnote-253552869
Ref: Library<46>-Footnote-263552926
Ref: Library<46>-Footnote-273552969
Ref: Library<46>-Footnote-283553025
Ref: Library<46>-Footnote-293553082
Ref: Library<46>-Footnote-303553139
Ref: Library<46>-Footnote-313553182
Ref: Library<46>-Footnote-323553239
Ref: Library<46>-Footnote-333553295
Ref: Library<46>-Footnote-343553338
Ref: Library<46>-Footnote-353553394
Ref: Library<46>-Footnote-363553450
Node: Documentation<21>3553516
Ref: whatsnew/changelog id2553553629
Ref: 18723553629
Ref: Documentation<21>-Footnote-13553938
Ref: Documentation<21>-Footnote-23553993
Node: Tests<24>3554048
Ref: whatsnew/changelog id2563554159
Ref: 18743554159
Ref: Tests<24>-Footnote-13554735
Ref: Tests<24>-Footnote-23554791
Ref: Tests<24>-Footnote-33554846
Node: Build<25>3554901
Ref: whatsnew/changelog id2573555006
Ref: 18753555006
Ref: Build<25>-Footnote-13555685
Ref: Build<25>-Footnote-23555740
Ref: Build<25>-Footnote-33555795
Ref: Build<25>-Footnote-43555851
Node: Windows<22>3555906
Ref: whatsnew/changelog id2583556011
Ref: 18773556011
Ref: Windows<22>-Footnote-13557030
Ref: Windows<22>-Footnote-23557086
Ref: Windows<22>-Footnote-33557142
Ref: Windows<22>-Footnote-43557198
Ref: Windows<22>-Footnote-53557254
Ref: Windows<22>-Footnote-63557310
Ref: Windows<22>-Footnote-73557366
Ref: Windows<22>-Footnote-83557422
Node: macOS<16>3557478
Ref: whatsnew/changelog id2593557583
Ref: 18783557583
Ref: macOS<16>-Footnote-13557713
Node: C API<24>3557769
Ref: whatsnew/changelog id2603557854
Ref: 18793557854
Ref: C API<24>-Footnote-13558951
Ref: C API<24>-Footnote-23559007
Ref: C API<24>-Footnote-33559062
Ref: C API<24>-Footnote-43559118
Ref: C API<24>-Footnote-53559173
Node: Python 3 12 0 alpha 53559215
Ref: whatsnew/changelog python-3-12-0-alpha-53559342
Ref: 187a3559342
Node: Security<21>3559635
Ref: whatsnew/changelog id2613559735
Ref: 187b3559735
Ref: Security<21>-Footnote-13560113
Ref: Security<21>-Footnote-23560168
Node: Core and Builtins<43>3560216
Ref: whatsnew/changelog id2633560336
Ref: 187c3560336
Ref: Core and Builtins<43>-Footnote-13563235
Ref: Core and Builtins<43>-Footnote-23563290
Ref: Core and Builtins<43>-Footnote-33563345
Ref: Core and Builtins<43>-Footnote-43563401
Ref: Core and Builtins<43>-Footnote-53563457
Ref: Core and Builtins<43>-Footnote-63563513
Ref: Core and Builtins<43>-Footnote-73563569
Ref: Core and Builtins<43>-Footnote-83563625
Ref: Core and Builtins<43>-Footnote-93563681
Ref: Core and Builtins<43>-Footnote-103563737
Ref: Core and Builtins<43>-Footnote-113563794
Ref: Core and Builtins<43>-Footnote-123563851
Ref: Core and Builtins<43>-Footnote-133563908
Ref: Core and Builtins<43>-Footnote-143563965
Ref: Core and Builtins<43>-Footnote-153564021
Ref: Core and Builtins<43>-Footnote-163564078
Node: Library<47>3564135
Ref: whatsnew/changelog id2643564260
Ref: 187f3564260
Ref: Library<47>-Footnote-13569520
Ref: Library<47>-Footnote-23569585
Ref: Library<47>-Footnote-33569641
Ref: Library<47>-Footnote-43569697
Ref: Library<47>-Footnote-53569753
Ref: Library<47>-Footnote-63569809
Ref: Library<47>-Footnote-73569865
Ref: Library<47>-Footnote-83569920
Ref: Library<47>-Footnote-93569962
Ref: Library<47>-Footnote-103570018
Ref: Library<47>-Footnote-113570075
Ref: Library<47>-Footnote-123570132
Ref: Library<47>-Footnote-133570188
Ref: Library<47>-Footnote-143570245
Ref: Library<47>-Footnote-153570302
Ref: Library<47>-Footnote-163570359
Ref: Library<47>-Footnote-173570415
Ref: Library<47>-Footnote-183570472
Ref: Library<47>-Footnote-193570529
Ref: Library<47>-Footnote-203570585
Ref: Library<47>-Footnote-213570641
Ref: Library<47>-Footnote-223570697
Ref: Library<47>-Footnote-233570753
Ref: Library<47>-Footnote-243570809
Ref: Library<47>-Footnote-253570865
Ref: Library<47>-Footnote-263570921
Ref: Library<47>-Footnote-273570977
Ref: Library<47>-Footnote-283571043
Ref: Library<47>-Footnote-293571109
Ref: Library<47>-Footnote-303571175
Node: Documentation<22>3571231
Ref: whatsnew/changelog id2653571344
Ref: 18883571344
Ref: Documentation<22>-Footnote-13571629
Node: Tests<25>3571684
Ref: whatsnew/changelog id2663571795
Ref: 18893571795
Ref: Tests<25>-Footnote-13571957
Node: Build<26>3572013
Ref: whatsnew/changelog id2673572118
Ref: 188a3572118
Ref: Build<26>-Footnote-13573557
Ref: Build<26>-Footnote-23573613
Ref: Build<26>-Footnote-33573669
Ref: Build<26>-Footnote-43573724
Ref: Build<26>-Footnote-53573780
Ref: Build<26>-Footnote-63573822
Ref: Build<26>-Footnote-73573878
Ref: Build<26>-Footnote-83573934
Ref: Build<26>-Footnote-93573989
Ref: Build<26>-Footnote-103574044
Node: Windows<23>3574100
Ref: whatsnew/changelog id2683574187
Ref: 188b3574187
Ref: Windows<23>-Footnote-13575439
Ref: Windows<23>-Footnote-23575495
Ref: Windows<23>-Footnote-33575551
Ref: Windows<23>-Footnote-43575606
Ref: Windows<23>-Footnote-53575662
Ref: Windows<23>-Footnote-63575717
Ref: Windows<23>-Footnote-73575773
Node: Python 3 12 0 alpha 43575829
Ref: whatsnew/changelog python-3-12-0-alpha-43575956
Ref: 188c3575956
Node: Core and Builtins<44>3576431
Ref: whatsnew/changelog id2693576530
Ref: 188d3576530
Ref: Core and Builtins<44>-Footnote-13578432
Ref: Core and Builtins<44>-Footnote-23578488
Ref: Core and Builtins<44>-Footnote-33578543
Ref: Core and Builtins<44>-Footnote-43578598
Ref: Core and Builtins<44>-Footnote-53578654
Ref: Core and Builtins<44>-Footnote-63578710
Ref: Core and Builtins<44>-Footnote-73578766
Ref: Core and Builtins<44>-Footnote-83578822
Ref: Core and Builtins<44>-Footnote-93578878
Ref: Core and Builtins<44>-Footnote-103578934
Ref: Core and Builtins<44>-Footnote-113578990
Ref: Core and Builtins<44>-Footnote-123579033
Ref: Core and Builtins<44>-Footnote-133579090
Node: Library<48>3579147
Ref: whatsnew/changelog id2703579276
Ref: 188f3579276
Ref: Library<48>-Footnote-13579465
Node: Core and Builtins<45>3579521
Ref: whatsnew/changelog id2713579640
Ref: 18913579640
Ref: Core and Builtins<45>-Footnote-13582373
Ref: Core and Builtins<45>-Footnote-23582429
Ref: Core and Builtins<45>-Footnote-33582485
Ref: Core and Builtins<45>-Footnote-43582540
Ref: Core and Builtins<45>-Footnote-53582596
Ref: Core and Builtins<45>-Footnote-63582651
Ref: Core and Builtins<45>-Footnote-73582707
Ref: Core and Builtins<45>-Footnote-83582762
Ref: Core and Builtins<45>-Footnote-93582817
Ref: Core and Builtins<45>-Footnote-103582872
Ref: Core and Builtins<45>-Footnote-113582929
Ref: Core and Builtins<45>-Footnote-123582986
Ref: Core and Builtins<45>-Footnote-133583043
Ref: Core and Builtins<45>-Footnote-143583100
Ref: Core and Builtins<45>-Footnote-153583156
Ref: Core and Builtins<45>-Footnote-163583212
Ref: Core and Builtins<45>-Footnote-173583268
Ref: Core and Builtins<45>-Footnote-183583324
Node: Library<49>3583380
Ref: whatsnew/changelog id2723583509
Ref: 18933583509
Ref: Library<49>-Footnote-13583647
Node: Core and Builtins<46>3583702
Ref: whatsnew/changelog id2733583821
Ref: 18953583821
Ref: Core and Builtins<46>-Footnote-13584096
Node: Library<50>3584161
Ref: whatsnew/changelog id2743584286
Ref: 18963584286
Ref: Library<50>-Footnote-13594542
Ref: Library<50>-Footnote-23594598
Ref: Library<50>-Footnote-33594654
Ref: Library<50>-Footnote-43594710
Ref: Library<50>-Footnote-53594766
Ref: Library<50>-Footnote-63594821
Ref: Library<50>-Footnote-73594876
Ref: Library<50>-Footnote-83594932
Ref: Library<50>-Footnote-93594988
Ref: Library<50>-Footnote-103595043
Ref: Library<50>-Footnote-113595100
Ref: Library<50>-Footnote-123595156
Ref: Library<50>-Footnote-133595213
Ref: Library<50>-Footnote-143595269
Ref: Library<50>-Footnote-153595325
Ref: Library<50>-Footnote-163595382
Ref: Library<50>-Footnote-173595439
Ref: Library<50>-Footnote-183595496
Ref: Library<50>-Footnote-193595553
Ref: Library<50>-Footnote-203595610
Ref: Library<50>-Footnote-213595667
Ref: Library<50>-Footnote-223595724
Ref: Library<50>-Footnote-233595780
Ref: Library<50>-Footnote-243595837
Ref: Library<50>-Footnote-253595894
Ref: Library<50>-Footnote-263595951
Ref: Library<50>-Footnote-273596007
Ref: Library<50>-Footnote-283596064
Ref: Library<50>-Footnote-293596121
Ref: Library<50>-Footnote-303596178
Ref: Library<50>-Footnote-313596235
Ref: Library<50>-Footnote-323596301
Ref: Library<50>-Footnote-333596358
Ref: Library<50>-Footnote-343596414
Ref: Library<50>-Footnote-353596470
Ref: Library<50>-Footnote-363596526
Ref: Library<50>-Footnote-373596582
Ref: Library<50>-Footnote-383596638
Ref: Library<50>-Footnote-393596694
Ref: Library<50>-Footnote-403596750
Ref: Library<50>-Footnote-413596806
Ref: Library<50>-Footnote-423596862
Ref: Library<50>-Footnote-433596905
Ref: Library<50>-Footnote-443596961
Ref: Library<50>-Footnote-453597017
Ref: Library<50>-Footnote-463597073
Ref: Library<50>-Footnote-473597129
Ref: Library<50>-Footnote-483597185
Ref: Library<50>-Footnote-493597241
Ref: Library<50>-Footnote-503597297
Ref: Library<50>-Footnote-513597353
Ref: Library<50>-Footnote-523597409
Ref: Library<50>-Footnote-533597465
Ref: Library<50>-Footnote-543597521
Ref: Library<50>-Footnote-553597587
Ref: Library<50>-Footnote-563597653
Node: Documentation<23>3597719
Ref: whatsnew/changelog id2753597832
Ref: 18a03597832
Ref: Documentation<23>-Footnote-13598415
Ref: Documentation<23>-Footnote-23598471
Ref: Documentation<23>-Footnote-33598527
Node: Tests<26>3598592
Ref: whatsnew/changelog id2763598703
Ref: 18a23598703
Ref: Tests<26>-Footnote-13599158
Ref: Tests<26>-Footnote-23599214
Ref: Tests<26>-Footnote-33599270
Node: Build<27>3599325
Ref: whatsnew/changelog id2773599430
Ref: 18a33599430
Ref: Build<27>-Footnote-13600317
Ref: Build<27>-Footnote-23600373
Ref: Build<27>-Footnote-33600428
Node: Windows<24>3600493
Ref: whatsnew/changelog id2783600598
Ref: 18a43600598
Ref: Windows<24>-Footnote-13601525
Ref: Windows<24>-Footnote-23601581
Ref: Windows<24>-Footnote-33601636
Ref: Windows<24>-Footnote-43601691
Ref: Windows<24>-Footnote-53601746
Ref: Windows<24>-Footnote-63601811
Node: macOS<17>3601876
Ref: whatsnew/changelog id2793601987
Ref: 18a73601987
Ref: macOS<17>-Footnote-13602271
Ref: macOS<17>-Footnote-23602327
Node: Tools/Demos<15>3602383
Ref: whatsnew/changelog id2803602492
Ref: 18a83602492
Ref: Tools/Demos<15>-Footnote-13602868
Ref: Tools/Demos<15>-Footnote-23602933
Node: C API<25>3602989
Ref: whatsnew/changelog id2813603080
Ref: 18a93603080
Ref: C API<25>-Footnote-13603649
Ref: C API<25>-Footnote-23603704
Ref: C API<25>-Footnote-33603759
Node: Python 3 12 0 alpha 33603814
Ref: whatsnew/changelog python-3-12-0-alpha-33603941
Ref: 18aa3603941
Node: Security<22>3604374
Ref: whatsnew/changelog id2823604474
Ref: 18ab3604474
Ref: Security<22>-Footnote-13605034
Ref: Security<22>-Footnote-23605090
Node: Core and Builtins<47>3605145
Ref: whatsnew/changelog id2833605265
Ref: 18ac3605265
Ref: Core and Builtins<47>-Footnote-13606585
Ref: Core and Builtins<47>-Footnote-23606640
Ref: Core and Builtins<47>-Footnote-33606695
Ref: Core and Builtins<47>-Footnote-43606750
Ref: Core and Builtins<47>-Footnote-53606805
Ref: Core and Builtins<47>-Footnote-63606860
Ref: Core and Builtins<47>-Footnote-73606915
Node: Library<51>3606970
Ref: whatsnew/changelog id2843607099
Ref: 18ad3607099
Ref: Library<51>-Footnote-13607434
Ref: Library<51>-Footnote-23607489
Node: Core and Builtins<48>3607544
Ref: whatsnew/changelog id2853607663
Ref: 18ae3607663
Ref: Core and Builtins<48>-Footnote-13609476
Ref: Core and Builtins<48>-Footnote-23609531
Ref: Core and Builtins<48>-Footnote-33609586
Ref: Core and Builtins<48>-Footnote-43609641
Ref: Core and Builtins<48>-Footnote-53609696
Ref: Core and Builtins<48>-Footnote-63609751
Ref: Core and Builtins<48>-Footnote-73609806
Ref: Core and Builtins<48>-Footnote-83609871
Ref: Core and Builtins<48>-Footnote-93609936
Node: Library<52>3610001
Ref: whatsnew/changelog id2863610126
Ref: 18af3610126
Ref: Library<52>-Footnote-13616368
Ref: Library<52>-Footnote-23616424
Ref: Library<52>-Footnote-33616479
Ref: Library<52>-Footnote-43616534
Ref: Library<52>-Footnote-53616589
Ref: Library<52>-Footnote-63616644
Ref: Library<52>-Footnote-73616699
Ref: Library<52>-Footnote-83616754
Ref: Library<52>-Footnote-93616809
Ref: Library<52>-Footnote-103616864
Ref: Library<52>-Footnote-113616920
Ref: Library<52>-Footnote-123616976
Ref: Library<52>-Footnote-133617032
Ref: Library<52>-Footnote-143617088
Ref: Library<52>-Footnote-153617144
Ref: Library<52>-Footnote-163617200
Ref: Library<52>-Footnote-173617256
Ref: Library<52>-Footnote-183617312
Ref: Library<52>-Footnote-193617368
Ref: Library<52>-Footnote-203617424
Ref: Library<52>-Footnote-213617480
Ref: Library<52>-Footnote-223617536
Ref: Library<52>-Footnote-233617592
Ref: Library<52>-Footnote-243617648
Ref: Library<52>-Footnote-253617704
Ref: Library<52>-Footnote-263617760
Ref: Library<52>-Footnote-273617816
Ref: Library<52>-Footnote-283617872
Ref: Library<52>-Footnote-293617928
Ref: Library<52>-Footnote-303617984
Ref: Library<52>-Footnote-313618040
Ref: Library<52>-Footnote-323618106
Ref: Library<52>-Footnote-333618172
Ref: Library<52>-Footnote-343618238
Node: Documentation<24>3618304
Ref: whatsnew/changelog id2873618417
Ref: 18b33618417
Ref: Documentation<24>-Footnote-13619186
Ref: Documentation<24>-Footnote-23619241
Ref: Documentation<24>-Footnote-33619293
Ref: Documentation<24>-Footnote-43619317
Ref: Documentation<24>-Footnote-53619372
Ref: Documentation<24>-Footnote-63619427
Ref: Documentation<24>-Footnote-73619482
Node: Tests<27>3619547
Ref: whatsnew/changelog id2883619658
Ref: 18b43619658
Ref: Tests<27>-Footnote-13620435
Ref: Tests<27>-Footnote-23620490
Ref: Tests<27>-Footnote-33620545
Ref: Tests<27>-Footnote-43620600
Ref: Tests<27>-Footnote-53620655
Ref: Tests<27>-Footnote-63620710
Node: Build<28>3620765
Ref: whatsnew/changelog id2893620870
Ref: 18b53620870
Ref: Build<28>-Footnote-13621834
Ref: Build<28>-Footnote-23621889
Ref: Build<28>-Footnote-33621944
Ref: Build<28>-Footnote-43621999
Ref: Build<28>-Footnote-53622054
Node: Windows<25>3622109
Ref: whatsnew/changelog id2903622214
Ref: 18b63622214
Ref: Windows<25>-Footnote-13622748
Ref: Windows<25>-Footnote-23622803
Ref: Windows<25>-Footnote-33622858
Ref: Windows<25>-Footnote-43622913
Node: macOS<18>3622978
Ref: whatsnew/changelog id2913623089
Ref: 18b73623089
Ref: macOS<18>-Footnote-13623359
Ref: macOS<18>-Footnote-23623414
Node: Tools/Demos<16>3623469
Ref: whatsnew/changelog id2923623578
Ref: 18b83623578
Ref: Tools/Demos<16>-Footnote-13624070
Node: C API<26>3624125
Ref: whatsnew/changelog id2933624216
Ref: 18b93624216
Ref: C API<26>-Footnote-13625037
Ref: C API<26>-Footnote-23625092
Ref: C API<26>-Footnote-33625147
Node: Python 3 12 0 alpha 23625202
Ref: whatsnew/changelog python-3-12-0-alpha-23625329
Ref: 18bb3625329
Node: Security<23>3625726
Ref: whatsnew/changelog id2943625826
Ref: 18bc3625826
Ref: Security<23>-Footnote-13626959
Ref: Security<23>-Footnote-23627014
Ref: Security<23>-Footnote-33627073
Ref: Security<23>-Footnote-43627132
Ref: Security<23>-Footnote-53627191
Node: Core and Builtins<49>3627246
Ref: whatsnew/changelog id2953627364
Ref: 18bd3627364
Ref: Core and Builtins<49>-Footnote-13634077
Ref: Core and Builtins<49>-Footnote-23634132
Ref: Core and Builtins<49>-Footnote-33634187
Ref: Core and Builtins<49>-Footnote-43634242
Ref: Core and Builtins<49>-Footnote-53634297
Ref: Core and Builtins<49>-Footnote-63634352
Ref: Core and Builtins<49>-Footnote-73634407
Ref: Core and Builtins<49>-Footnote-83634462
Ref: Core and Builtins<49>-Footnote-93634517
Ref: Core and Builtins<49>-Footnote-103634572
Ref: Core and Builtins<49>-Footnote-113634628
Ref: Core and Builtins<49>-Footnote-123634684
Ref: Core and Builtins<49>-Footnote-133634740
Ref: Core and Builtins<49>-Footnote-143634796
Ref: Core and Builtins<49>-Footnote-153634852
Ref: Core and Builtins<49>-Footnote-163634908
Ref: Core and Builtins<49>-Footnote-173634964
Ref: Core and Builtins<49>-Footnote-183635020
Ref: Core and Builtins<49>-Footnote-193635076
Ref: Core and Builtins<49>-Footnote-203635132
Ref: Core and Builtins<49>-Footnote-213635188
Ref: Core and Builtins<49>-Footnote-223635244
Ref: Core and Builtins<49>-Footnote-233635300
Ref: Core and Builtins<49>-Footnote-243635356
Ref: Core and Builtins<49>-Footnote-253635399
Ref: Core and Builtins<49>-Footnote-263635455
Ref: Core and Builtins<49>-Footnote-273635511
Node: Build<29>3635567
Ref: whatsnew/changelog id2963635694
Ref: 18c43635694
Ref: Build<29>-Footnote-13635879
Node: Core and Builtins<50>3635934
Ref: whatsnew/changelog id2973636051
Ref: 18c53636051
Ref: Core and Builtins<50>-Footnote-13637188
Ref: Core and Builtins<50>-Footnote-23637243
Ref: Core and Builtins<50>-Footnote-33637298
Ref: Core and Builtins<50>-Footnote-43637353
Ref: Core and Builtins<50>-Footnote-53637408
Ref: Core and Builtins<50>-Footnote-63637463
Node: Library<53>3637518
Ref: whatsnew/changelog id2983637643
Ref: 18c83637643
Ref: Library<53>-Footnote-13643550
Ref: Library<53>-Footnote-23643605
Ref: Library<53>-Footnote-33643660
Ref: Library<53>-Footnote-43643715
Ref: Library<53>-Footnote-53643770
Ref: Library<53>-Footnote-63643825
Ref: Library<53>-Footnote-73643880
Ref: Library<53>-Footnote-83643935
Ref: Library<53>-Footnote-93643990
Ref: Library<53>-Footnote-103644045
Ref: Library<53>-Footnote-113644101
Ref: Library<53>-Footnote-123644157
Ref: Library<53>-Footnote-133644213
Ref: Library<53>-Footnote-143644256
Ref: Library<53>-Footnote-153644312
Ref: Library<53>-Footnote-163644368
Ref: Library<53>-Footnote-173644424
Ref: Library<53>-Footnote-183644480
Ref: Library<53>-Footnote-193644536
Ref: Library<53>-Footnote-203644592
Ref: Library<53>-Footnote-213644648
Ref: Library<53>-Footnote-223644704
Ref: Library<53>-Footnote-233644760
Ref: Library<53>-Footnote-243644816
Ref: Library<53>-Footnote-253644872
Ref: Library<53>-Footnote-263644928
Ref: Library<53>-Footnote-273644984
Ref: Library<53>-Footnote-283645040
Ref: Library<53>-Footnote-293645096
Ref: Library<53>-Footnote-303645152
Ref: Library<53>-Footnote-313645208
Ref: Library<53>-Footnote-323645264
Ref: Library<53>-Footnote-333645307
Ref: Library<53>-Footnote-343645363
Ref: Library<53>-Footnote-353645419
Ref: Library<53>-Footnote-363645475
Ref: Library<53>-Footnote-373645531
Ref: Library<53>-Footnote-383645574
Ref: Library<53>-Footnote-393645630
Ref: Library<53>-Footnote-403645686
Ref: Library<53>-Footnote-413645752
Ref: Library<53>-Footnote-423645818
Node: Documentation<25>3645884
Ref: whatsnew/changelog id2993645997
Ref: 18cd3645997
Ref: Documentation<25>-Footnote-13646316
Ref: Documentation<25>-Footnote-23646371
Node: Tests<28>3646426
Ref: whatsnew/changelog id3003646537
Ref: 18ce3646537
Ref: Tests<28>-Footnote-13647425
Ref: Tests<28>-Footnote-23647480
Ref: Tests<28>-Footnote-33647535
Ref: Tests<28>-Footnote-43647590
Ref: Tests<28>-Footnote-53647645
Node: Build<30>3647710
Ref: whatsnew/changelog id3013647815
Ref: 18cf3647815
Ref: Build<30>-Footnote-13649508
Ref: Build<30>-Footnote-23649563
Ref: Build<30>-Footnote-33649618
Ref: Build<30>-Footnote-43649673
Ref: Build<30>-Footnote-53649728
Ref: Build<30>-Footnote-63649783
Ref: Build<30>-Footnote-73649838
Ref: Build<30>-Footnote-83649928
Ref: Build<30>-Footnote-93649983
Ref: Build<30>-Footnote-103650038
Node: Windows<26>3650094
Ref: whatsnew/changelog id3023650199
Ref: 18d13650199
Ref: Windows<26>-Footnote-13650904
Ref: Windows<26>-Footnote-23650959
Ref: Windows<26>-Footnote-33651015
Ref: Windows<26>-Footnote-43651070
Ref: Windows<26>-Footnote-53651125
Ref: Windows<26>-Footnote-63651180
Node: macOS<19>3651235
Ref: whatsnew/changelog id3033651340
Ref: 18d23651340
Ref: macOS<19>-Footnote-13651471
Node: C API<27>3651526
Ref: whatsnew/changelog id3043651611
Ref: 18d33651611
Ref: C API<27>-Footnote-13653688
Ref: C API<27>-Footnote-23653743
Ref: C API<27>-Footnote-33653798
Ref: C API<27>-Footnote-43653853
Ref: C API<27>-Footnote-53653908
Ref: C API<27>-Footnote-63653963
Ref: C API<27>-Footnote-73654018
Node: Python 3 12 0 alpha 13654073
Ref: whatsnew/changelog python-3-12-0-alpha-13654199
Ref: 18d53654199
Node: Security<24>3655194
Ref: whatsnew/changelog id3053655294
Ref: 18d63655294
Ref: Security<24>-Footnote-13657131
Ref: Security<24>-Footnote-23657186
Ref: Security<24>-Footnote-33657241
Ref: Security<24>-Footnote-43657313
Ref: Security<24>-Footnote-53657369
Ref: Security<24>-Footnote-63657424
Ref: Security<24>-Footnote-73657479
Ref: Security<24>-Footnote-83657534
Node: Core and Builtins<51>3657589
Ref: whatsnew/changelog id3063657709
Ref: 18d73657709
Ref: Core and Builtins<51>-Footnote-13658989
Ref: Core and Builtins<51>-Footnote-23659044
Ref: Core and Builtins<51>-Footnote-33659099
Ref: Core and Builtins<51>-Footnote-43659154
Ref: Core and Builtins<51>-Footnote-53659209
Ref: Core and Builtins<51>-Footnote-63659264
Ref: Core and Builtins<51>-Footnote-73659319
Ref: Core and Builtins<51>-Footnote-83659374
Node: Library<54>3659429
Ref: whatsnew/changelog id3073659558
Ref: 18d83659558
Ref: Library<54>-Footnote-13659825
Ref: Library<54>-Footnote-23659880
Node: Core and Builtins<52>3659935
Ref: whatsnew/changelog id3083660054
Ref: 18d93660054
Ref: Core and Builtins<52>-Footnote-13663503
Ref: Core and Builtins<52>-Footnote-23663558
Ref: Core and Builtins<52>-Footnote-33663613
Ref: Core and Builtins<52>-Footnote-43663668
Ref: Core and Builtins<52>-Footnote-53663723
Ref: Core and Builtins<52>-Footnote-63663778
Ref: Core and Builtins<52>-Footnote-73663833
Ref: Core and Builtins<52>-Footnote-83663888
Ref: Core and Builtins<52>-Footnote-93663943
Ref: Core and Builtins<52>-Footnote-103663998
Ref: Core and Builtins<52>-Footnote-113664054
Ref: Core and Builtins<52>-Footnote-123664110
Ref: Core and Builtins<52>-Footnote-133664166
Ref: Core and Builtins<52>-Footnote-143664222
Ref: Core and Builtins<52>-Footnote-153664278
Ref: Core and Builtins<52>-Footnote-163664334
Ref: Core and Builtins<52>-Footnote-173664390
Node: Library<55>3664446
Ref: whatsnew/changelog id3093664575
Ref: 18de3664575
Ref: Library<55>-Footnote-13664711
Node: Core and Builtins<53>3664766
Ref: whatsnew/changelog id3103664885
Ref: 18df3664885
Ref: Core and Builtins<53>-Footnote-13666612
Ref: Core and Builtins<53>-Footnote-23666667
Ref: Core and Builtins<53>-Footnote-33666722
Ref: Core and Builtins<53>-Footnote-43666777
Ref: Core and Builtins<53>-Footnote-53666832
Ref: Core and Builtins<53>-Footnote-63666887
Ref: Core and Builtins<53>-Footnote-73666942
Ref: Core and Builtins<53>-Footnote-83666997
Ref: Core and Builtins<53>-Footnote-93667052
Ref: Core and Builtins<53>-Footnote-103667107
Ref: Core and Builtins<53>-Footnote-113667163
Node: Library<56>3667219
Ref: whatsnew/changelog id3113667348
Ref: 18e13667348
Ref: Library<56>-Footnote-13667556
Ref: Library<56>-Footnote-23667611
Node: Core and Builtins<54>3667666
Ref: whatsnew/changelog id3123667785
Ref: 18e23667785
Ref: Core and Builtins<54>-Footnote-13677045
Ref: Core and Builtins<54>-Footnote-23677100
Ref: Core and Builtins<54>-Footnote-33677155
Ref: Core and Builtins<54>-Footnote-43677210
Ref: Core and Builtins<54>-Footnote-53677265
Ref: Core and Builtins<54>-Footnote-63677320
Ref: Core and Builtins<54>-Footnote-73677375
Ref: Core and Builtins<54>-Footnote-83677417
Ref: Core and Builtins<54>-Footnote-93677472
Ref: Core and Builtins<54>-Footnote-103677527
Ref: Core and Builtins<54>-Footnote-113677583
Ref: Core and Builtins<54>-Footnote-123677639
Ref: Core and Builtins<54>-Footnote-133677695
Ref: Core and Builtins<54>-Footnote-143677751
Ref: Core and Builtins<54>-Footnote-153677807
Ref: Core and Builtins<54>-Footnote-163677863
Ref: Core and Builtins<54>-Footnote-173677919
Ref: Core and Builtins<54>-Footnote-183677975
Ref: Core and Builtins<54>-Footnote-193678031
Ref: Core and Builtins<54>-Footnote-203678087
Ref: Core and Builtins<54>-Footnote-213678143
Ref: Core and Builtins<54>-Footnote-223678199
Ref: Core and Builtins<54>-Footnote-233678255
Ref: Core and Builtins<54>-Footnote-243678311
Ref: Core and Builtins<54>-Footnote-253678367
Ref: Core and Builtins<54>-Footnote-263678423
Ref: Core and Builtins<54>-Footnote-273678479
Ref: Core and Builtins<54>-Footnote-283678535
Ref: Core and Builtins<54>-Footnote-293678591
Ref: Core and Builtins<54>-Footnote-303678647
Ref: Core and Builtins<54>-Footnote-313678703
Ref: Core and Builtins<54>-Footnote-323678759
Ref: Core and Builtins<54>-Footnote-333678815
Ref: Core and Builtins<54>-Footnote-343678871
Ref: Core and Builtins<54>-Footnote-353678927
Ref: Core and Builtins<54>-Footnote-363678983
Ref: Core and Builtins<54>-Footnote-373679039
Ref: Core and Builtins<54>-Footnote-383679095
Ref: Core and Builtins<54>-Footnote-393679151
Ref: Core and Builtins<54>-Footnote-403679207
Ref: Core and Builtins<54>-Footnote-413679263
Ref: Core and Builtins<54>-Footnote-423679319
Ref: Core and Builtins<54>-Footnote-433679375
Ref: Core and Builtins<54>-Footnote-443679431
Ref: Core and Builtins<54>-Footnote-453679487
Ref: Core and Builtins<54>-Footnote-463679543
Node: Library<57>3679599
Ref: whatsnew/changelog id3133679728
Ref: 18e43679728
Ref: Library<57>-Footnote-13679922
Node: Core and Builtins<55>3679977
Ref: whatsnew/changelog id3143680096
Ref: 18e73680096
Ref: Core and Builtins<55>-Footnote-13680564
Ref: Core and Builtins<55>-Footnote-23680619
Node: Library<58>3680674
Ref: whatsnew/changelog id3153680803
Ref: 18e83680803
Ref: Library<58>-Footnote-13681084
Node: Core and Builtins<56>3681139
Ref: whatsnew/changelog id3163681258
Ref: 18e93681258
Ref: Core and Builtins<56>-Footnote-13681454
Node: Library<59>3681509
Ref: whatsnew/changelog id3173681638
Ref: 18ea3681638
Ref: Library<59>-Footnote-13682081
Ref: Library<59>-Footnote-23682136
Node: Core and Builtins<57>3682191
Ref: whatsnew/changelog id3183682310
Ref: 18eb3682310
Ref: Core and Builtins<57>-Footnote-13687802
Ref: Core and Builtins<57>-Footnote-23687857
Ref: Core and Builtins<57>-Footnote-33687912
Ref: Core and Builtins<57>-Footnote-43687967
Ref: Core and Builtins<57>-Footnote-53688022
Ref: Core and Builtins<57>-Footnote-63688077
Ref: Core and Builtins<57>-Footnote-73688132
Ref: Core and Builtins<57>-Footnote-83688187
Ref: Core and Builtins<57>-Footnote-93688242
Ref: Core and Builtins<57>-Footnote-103688297
Ref: Core and Builtins<57>-Footnote-113688353
Ref: Core and Builtins<57>-Footnote-123688409
Ref: Core and Builtins<57>-Footnote-133688452
Ref: Core and Builtins<57>-Footnote-143688508
Ref: Core and Builtins<57>-Footnote-153688564
Ref: Core and Builtins<57>-Footnote-163688620
Ref: Core and Builtins<57>-Footnote-173688676
Ref: Core and Builtins<57>-Footnote-183688732
Ref: Core and Builtins<57>-Footnote-193688788
Ref: Core and Builtins<57>-Footnote-203688844
Ref: Core and Builtins<57>-Footnote-213688900
Ref: Core and Builtins<57>-Footnote-223688956
Ref: Core and Builtins<57>-Footnote-233689012
Ref: Core and Builtins<57>-Footnote-243689068
Ref: Core and Builtins<57>-Footnote-253689124
Ref: Core and Builtins<57>-Footnote-263689180
Ref: Core and Builtins<57>-Footnote-273689236
Ref: Core and Builtins<57>-Footnote-283689292
Ref: Core and Builtins<57>-Footnote-293689348
Ref: Core and Builtins<57>-Footnote-303689404
Ref: Core and Builtins<57>-Footnote-313689460
Ref: Core and Builtins<57>-Footnote-323689516
Ref: Core and Builtins<57>-Footnote-333689572
Ref: Core and Builtins<57>-Footnote-343689628
Node: Library<60>3689684
Ref: whatsnew/changelog id3193689813
Ref: 18ec3689813
Ref: Library<60>-Footnote-13690248
Node: Core and Builtins<58>3690303
Ref: whatsnew/changelog id3203690422
Ref: 18ed3690422
Ref: Core and Builtins<58>-Footnote-13695694
Ref: Core and Builtins<58>-Footnote-23695749
Ref: Core and Builtins<58>-Footnote-33695804
Ref: Core and Builtins<58>-Footnote-43695859
Ref: Core and Builtins<58>-Footnote-53695914
Ref: Core and Builtins<58>-Footnote-63695969
Ref: Core and Builtins<58>-Footnote-73696024
Ref: Core and Builtins<58>-Footnote-83696079
Ref: Core and Builtins<58>-Footnote-93696134
Ref: Core and Builtins<58>-Footnote-103696189
Ref: Core and Builtins<58>-Footnote-113696245
Ref: Core and Builtins<58>-Footnote-123696301
Ref: Core and Builtins<58>-Footnote-133696357
Ref: Core and Builtins<58>-Footnote-143696413
Ref: Core and Builtins<58>-Footnote-153696469
Ref: Core and Builtins<58>-Footnote-163696525
Ref: Core and Builtins<58>-Footnote-173696581
Ref: Core and Builtins<58>-Footnote-183696637
Ref: Core and Builtins<58>-Footnote-193696693
Ref: Core and Builtins<58>-Footnote-203696753
Ref: Core and Builtins<58>-Footnote-213696809
Ref: Core and Builtins<58>-Footnote-223696865
Ref: Core and Builtins<58>-Footnote-233696921
Ref: Core and Builtins<58>-Footnote-243696977
Ref: Core and Builtins<58>-Footnote-253697033
Ref: Core and Builtins<58>-Footnote-263697089
Ref: Core and Builtins<58>-Footnote-273697145
Ref: Core and Builtins<58>-Footnote-283697201
Ref: Core and Builtins<58>-Footnote-293697257
Ref: Core and Builtins<58>-Footnote-303697313
Ref: Core and Builtins<58>-Footnote-313697369
Ref: Core and Builtins<58>-Footnote-323697425
Node: Library<61>3697481
Ref: whatsnew/changelog id3213697610
Ref: 18ee3697610
Ref: Library<61>-Footnote-13697771
Node: Core and Builtins<59>3697826
Ref: whatsnew/changelog id3223697945
Ref: 18ef3697945
Ref: Core and Builtins<59>-Footnote-13698399
Ref: Core and Builtins<59>-Footnote-23698454
Node: Library<62>3698509
Ref: whatsnew/changelog id3233698638
Ref: 18f03698638
Ref: Library<62>-Footnote-13698791
Node: Core and Builtins<60>3698846
Ref: whatsnew/changelog id3243698965
Ref: 18f13698965
Ref: Core and Builtins<60>-Footnote-13699837
Ref: Core and Builtins<60>-Footnote-23699892
Ref: Core and Builtins<60>-Footnote-33699947
Ref: Core and Builtins<60>-Footnote-43700002
Ref: Core and Builtins<60>-Footnote-53700067
Ref: Core and Builtins<60>-Footnote-63700132
Node: Library<63>3700197
Ref: whatsnew/changelog id3253700322
Ref: 18f23700322
Ref: Library<63>-Footnote-13743645
Ref: Library<63>-Footnote-23743700
Ref: Library<63>-Footnote-33743755
Ref: Library<63>-Footnote-43743810
Ref: Library<63>-Footnote-53743865
Ref: Library<63>-Footnote-63743920
Ref: Library<63>-Footnote-73743975
Ref: Library<63>-Footnote-83744030
Ref: Library<63>-Footnote-93744085
Ref: Library<63>-Footnote-103744140
Ref: Library<63>-Footnote-113744196
Ref: Library<63>-Footnote-123744252
Ref: Library<63>-Footnote-133744308
Ref: Library<63>-Footnote-143744364
Ref: Library<63>-Footnote-153744420
Ref: Library<63>-Footnote-163744476
Ref: Library<63>-Footnote-173744532
Ref: Library<63>-Footnote-183744588
Ref: Library<63>-Footnote-193744644
Ref: Library<63>-Footnote-203744704
Ref: Library<63>-Footnote-213744760
Ref: Library<63>-Footnote-223744816
Ref: Library<63>-Footnote-233744872
Ref: Library<63>-Footnote-243744928
Ref: Library<63>-Footnote-253744984
Ref: Library<63>-Footnote-263745040
Ref: Library<63>-Footnote-273745096
Ref: Library<63>-Footnote-283745152
Ref: Library<63>-Footnote-293745208
Ref: Library<63>-Footnote-303745264
Ref: Library<63>-Footnote-313745320
Ref: Library<63>-Footnote-323745376
Ref: Library<63>-Footnote-333745432
Ref: Library<63>-Footnote-343745488
Ref: Library<63>-Footnote-353745544
Ref: Library<63>-Footnote-363745600
Ref: Library<63>-Footnote-373745656
Ref: Library<63>-Footnote-383745712
Ref: Library<63>-Footnote-393745768
Ref: Library<63>-Footnote-403745824
Ref: Library<63>-Footnote-413745880
Ref: Library<63>-Footnote-423745936
Ref: Library<63>-Footnote-433745992
Ref: Library<63>-Footnote-443746048
Ref: Library<63>-Footnote-453746104
Ref: Library<63>-Footnote-463746160
Ref: Library<63>-Footnote-473746216
Ref: Library<63>-Footnote-483746272
Ref: Library<63>-Footnote-493746328
Ref: Library<63>-Footnote-503746384
Ref: Library<63>-Footnote-513746440
Ref: Library<63>-Footnote-523746496
Ref: Library<63>-Footnote-533746552
Ref: Library<63>-Footnote-543746608
Ref: Library<63>-Footnote-553746664
Ref: Library<63>-Footnote-563746720
Ref: Library<63>-Footnote-573746776
Ref: Library<63>-Footnote-583746832
Ref: Library<63>-Footnote-593746888
Ref: Library<63>-Footnote-603746944
Ref: Library<63>-Footnote-613747000
Ref: Library<63>-Footnote-623747056
Ref: Library<63>-Footnote-633747112
Ref: Library<63>-Footnote-643747168
Ref: Library<63>-Footnote-653747224
Ref: Library<63>-Footnote-663747280
Ref: Library<63>-Footnote-673747336
Ref: Library<63>-Footnote-683747402
Ref: Library<63>-Footnote-693747458
Ref: Library<63>-Footnote-703747514
Ref: Library<63>-Footnote-713747570
Ref: Library<63>-Footnote-723747626
Ref: Library<63>-Footnote-733747682
Ref: Library<63>-Footnote-743747738
Ref: Library<63>-Footnote-753747794
Ref: Library<63>-Footnote-763747850
Ref: Library<63>-Footnote-773747906
Ref: Library<63>-Footnote-783747962
Ref: Library<63>-Footnote-793748018
Ref: Library<63>-Footnote-803748074
Ref: Library<63>-Footnote-813748130
Ref: Library<63>-Footnote-823748186
Ref: Library<63>-Footnote-833748242
Ref: Library<63>-Footnote-843748298
Ref: Library<63>-Footnote-853748354
Ref: Library<63>-Footnote-863748410
Ref: Library<63>-Footnote-873748466
Ref: Library<63>-Footnote-883748522
Ref: Library<63>-Footnote-893748578
Ref: Library<63>-Footnote-903748634
Ref: Library<63>-Footnote-913748690
Ref: Library<63>-Footnote-923748746
Ref: Library<63>-Footnote-933748802
Ref: Library<63>-Footnote-943748858
Ref: Library<63>-Footnote-953748914
Ref: Library<63>-Footnote-963748970
Ref: Library<63>-Footnote-973749026
Ref: Library<63>-Footnote-983749082
Ref: Library<63>-Footnote-993749138
Ref: Library<63>-Footnote-1003749194
Ref: Library<63>-Footnote-1013749251
Ref: Library<63>-Footnote-1023749308
Ref: Library<63>-Footnote-1033749365
Ref: Library<63>-Footnote-1043749422
Ref: Library<63>-Footnote-1053749479
Ref: Library<63>-Footnote-1063749536
Ref: Library<63>-Footnote-1073749593
Ref: Library<63>-Footnote-1083749650
Ref: Library<63>-Footnote-1093749707
Ref: Library<63>-Footnote-1103749764
Ref: Library<63>-Footnote-1113749821
Ref: Library<63>-Footnote-1123749878
Ref: Library<63>-Footnote-1133749935
Ref: Library<63>-Footnote-1143749992
Ref: Library<63>-Footnote-1153750049
Ref: Library<63>-Footnote-1163750106
Ref: Library<63>-Footnote-1173750163
Ref: Library<63>-Footnote-1183750220
Ref: Library<63>-Footnote-1193750277
Ref: Library<63>-Footnote-1203750334
Ref: Library<63>-Footnote-1213750391
Ref: Library<63>-Footnote-1223750448
Ref: Library<63>-Footnote-1233750505
Ref: Library<63>-Footnote-1243750549
Ref: Library<63>-Footnote-1253750606
Ref: Library<63>-Footnote-1263750663
Ref: Library<63>-Footnote-1273750720
Ref: Library<63>-Footnote-1283750777
Ref: Library<63>-Footnote-1293750834
Ref: Library<63>-Footnote-1303750891
Ref: Library<63>-Footnote-1313750948
Ref: Library<63>-Footnote-1323751005
Ref: Library<63>-Footnote-1333751062
Ref: Library<63>-Footnote-1343751119
Ref: Library<63>-Footnote-1353751176
Ref: Library<63>-Footnote-1363751233
Ref: Library<63>-Footnote-1373751290
Ref: Library<63>-Footnote-1383751347
Ref: Library<63>-Footnote-1393751404
Ref: Library<63>-Footnote-1403751462
Ref: Library<63>-Footnote-1413751519
Ref: Library<63>-Footnote-1423751576
Ref: Library<63>-Footnote-1433751620
Ref: Library<63>-Footnote-1443751677
Ref: Library<63>-Footnote-1453751734
Ref: Library<63>-Footnote-1463751791
Ref: Library<63>-Footnote-1473751848
Ref: Library<63>-Footnote-1483751905
Ref: Library<63>-Footnote-1493751962
Ref: Library<63>-Footnote-1503752019
Ref: Library<63>-Footnote-1513752076
Ref: Library<63>-Footnote-1523752133
Ref: Library<63>-Footnote-1533752190
Ref: Library<63>-Footnote-1543752247
Ref: Library<63>-Footnote-1553752304
Ref: Library<63>-Footnote-1563752361
Ref: Library<63>-Footnote-1573752418
Ref: Library<63>-Footnote-1583752475
Ref: Library<63>-Footnote-1593752532
Ref: Library<63>-Footnote-1603752589
Ref: Library<63>-Footnote-1613752646
Ref: Library<63>-Footnote-1623752703
Ref: Library<63>-Footnote-1633752747
Ref: Library<63>-Footnote-1643752804
Ref: Library<63>-Footnote-1653752861
Ref: Library<63>-Footnote-1663752918
Ref: Library<63>-Footnote-1673752975
Ref: Library<63>-Footnote-1683753032
Ref: Library<63>-Footnote-1693753089
Ref: Library<63>-Footnote-1703753146
Ref: Library<63>-Footnote-1713753203
Ref: Library<63>-Footnote-1723753260
Ref: Library<63>-Footnote-1733753317
Ref: Library<63>-Footnote-1743753374
Ref: Library<63>-Footnote-1753753431
Ref: Library<63>-Footnote-1763753488
Ref: Library<63>-Footnote-1773753545
Ref: Library<63>-Footnote-1783753602
Ref: Library<63>-Footnote-1793753659
Ref: Library<63>-Footnote-1803753716
Ref: Library<63>-Footnote-1813753773
Ref: Library<63>-Footnote-1823753817
Ref: Library<63>-Footnote-1833753874
Ref: Library<63>-Footnote-1843753931
Ref: Library<63>-Footnote-1853753988
Ref: Library<63>-Footnote-1863754045
Ref: Library<63>-Footnote-1873754102
Ref: Library<63>-Footnote-1883754159
Ref: Library<63>-Footnote-1893754216
Ref: Library<63>-Footnote-1903754273
Ref: Library<63>-Footnote-1913754330
Ref: Library<63>-Footnote-1923754387
Ref: Library<63>-Footnote-1933754444
Ref: Library<63>-Footnote-1943754501
Ref: Library<63>-Footnote-1953754558
Ref: Library<63>-Footnote-1963754615
Ref: Library<63>-Footnote-1973754672
Ref: Library<63>-Footnote-1983754729
Ref: Library<63>-Footnote-1993754786
Ref: Library<63>-Footnote-2003754843
Ref: Library<63>-Footnote-2013754900
Ref: Library<63>-Footnote-2023754957
Ref: Library<63>-Footnote-2033755014
Ref: Library<63>-Footnote-2043755071
Ref: Library<63>-Footnote-2053755128
Ref: Library<63>-Footnote-2063755185
Ref: Library<63>-Footnote-2073755242
Ref: Library<63>-Footnote-2083755299
Ref: Library<63>-Footnote-2093755356
Ref: Library<63>-Footnote-2103755413
Ref: Library<63>-Footnote-2113755470
Ref: Library<63>-Footnote-2123755527
Ref: Library<63>-Footnote-2133755584
Ref: Library<63>-Footnote-2143755641
Ref: Library<63>-Footnote-2153755698
Ref: Library<63>-Footnote-2163755755
Ref: Library<63>-Footnote-2173755812
Ref: Library<63>-Footnote-2183755869
Ref: Library<63>-Footnote-2193755926
Ref: Library<63>-Footnote-2203755983
Ref: Library<63>-Footnote-2213756040
Ref: Library<63>-Footnote-2223756097
Ref: Library<63>-Footnote-2233756154
Ref: Library<63>-Footnote-2243756211
Ref: Library<63>-Footnote-2253756268
Ref: Library<63>-Footnote-2263756325
Ref: Library<63>-Footnote-2273756392
Ref: Library<63>-Footnote-2283756459
Ref: Library<63>-Footnote-2293756526
Ref: Library<63>-Footnote-2303756583
Ref: Library<63>-Footnote-2313756650
Ref: Library<63>-Footnote-2323756717
Ref: Library<63>-Footnote-2333756784
Ref: Library<63>-Footnote-2343756851
Ref: Library<63>-Footnote-2353756918
Ref: Library<63>-Footnote-2363756985
Ref: Library<63>-Footnote-2373757052
Ref: Library<63>-Footnote-2383757119
Ref: Library<63>-Footnote-2393757186
Ref: Library<63>-Footnote-2403757253
Ref: Library<63>-Footnote-2413757320
Ref: Library<63>-Footnote-2423757387
Ref: Library<63>-Footnote-2433757454
Ref: Library<63>-Footnote-2443757521
Ref: Library<63>-Footnote-2453757588
Ref: Library<63>-Footnote-2463757655
Ref: Library<63>-Footnote-2473757722
Ref: Library<63>-Footnote-2483757789
Ref: Library<63>-Footnote-2493757856
Ref: Library<63>-Footnote-2503757923
Ref: Library<63>-Footnote-2513757990
Ref: Library<63>-Footnote-2523758057
Ref: Library<63>-Footnote-2533758124
Ref: Library<63>-Footnote-2543758191
Node: Documentation<26>3758258
Ref: whatsnew/changelog id3263758371
Ref: 190f3758371
Ref: Documentation<26>-Footnote-13762115
Ref: Documentation<26>-Footnote-23762170
Ref: Documentation<26>-Footnote-33762225
Ref: Documentation<26>-Footnote-43762271
Ref: Documentation<26>-Footnote-53762326
Ref: Documentation<26>-Footnote-63762381
Ref: Documentation<26>-Footnote-73762436
Ref: Documentation<26>-Footnote-83762491
Ref: Documentation<26>-Footnote-93762546
Ref: Documentation<26>-Footnote-103762601
Ref: Documentation<26>-Footnote-113762657
Ref: Documentation<26>-Footnote-123762713
Ref: Documentation<26>-Footnote-133762769
Ref: Documentation<26>-Footnote-143762825
Ref: Documentation<26>-Footnote-153762868
Ref: Documentation<26>-Footnote-163762924
Ref: Documentation<26>-Footnote-173762980
Ref: Documentation<26>-Footnote-183763036
Ref: Documentation<26>-Footnote-193763092
Ref: Documentation<26>-Footnote-203763148
Ref: Documentation<26>-Footnote-213763204
Ref: Documentation<26>-Footnote-223763260
Ref: Documentation<26>-Footnote-233763316
Ref: Documentation<26>-Footnote-243763382
Ref: Documentation<26>-Footnote-253763448
Ref: Documentation<26>-Footnote-263763514
Ref: Documentation<26>-Footnote-273763580
Node: Tests<29>3763646
Ref: whatsnew/changelog id3273763757
Ref: 19163763757
Ref: Tests<29>-Footnote-13769137
Ref: Tests<29>-Footnote-23769192
Ref: Tests<29>-Footnote-33769247
Ref: Tests<29>-Footnote-43769302
Ref: Tests<29>-Footnote-53769357
Ref: Tests<29>-Footnote-63769444
Ref: Tests<29>-Footnote-73769499
Ref: Tests<29>-Footnote-83769554
Ref: Tests<29>-Footnote-93769609
Ref: Tests<29>-Footnote-103769664
Ref: Tests<29>-Footnote-113769720
Ref: Tests<29>-Footnote-123769776
Ref: Tests<29>-Footnote-133769832
Ref: Tests<29>-Footnote-143769888
Ref: Tests<29>-Footnote-153769944
Ref: Tests<29>-Footnote-163770000
Ref: Tests<29>-Footnote-173770056
Ref: Tests<29>-Footnote-183770112
Ref: Tests<29>-Footnote-193770168
Ref: Tests<29>-Footnote-203770224
Ref: Tests<29>-Footnote-213770280
Ref: Tests<29>-Footnote-223770336
Ref: Tests<29>-Footnote-233770392
Ref: Tests<29>-Footnote-243770448
Ref: Tests<29>-Footnote-253770504
Ref: Tests<29>-Footnote-263770560
Ref: Tests<29>-Footnote-273770616
Ref: Tests<29>-Footnote-283770672
Ref: Tests<29>-Footnote-293770728
Ref: Tests<29>-Footnote-303770784
Ref: Tests<29>-Footnote-313770840
Ref: Tests<29>-Footnote-323770896
Ref: Tests<29>-Footnote-333770952
Ref: Tests<29>-Footnote-343771008
Ref: Tests<29>-Footnote-353771064
Ref: Tests<29>-Footnote-363771120
Node: Build<31>3771186
Ref: whatsnew/changelog id3283771291
Ref: 191a3771291
Ref: Build<31>-Footnote-13776776
Ref: Build<31>-Footnote-23776831
Ref: Build<31>-Footnote-33776886
Ref: Build<31>-Footnote-43776941
Ref: Build<31>-Footnote-53776996
Ref: Build<31>-Footnote-63777051
Ref: Build<31>-Footnote-73777106
Ref: Build<31>-Footnote-83777161
Ref: Build<31>-Footnote-93777216
Ref: Build<31>-Footnote-103777271
Ref: Build<31>-Footnote-113777327
Ref: Build<31>-Footnote-123777383
Ref: Build<31>-Footnote-133777439
Ref: Build<31>-Footnote-143777495
Ref: Build<31>-Footnote-153777551
Ref: Build<31>-Footnote-163777607
Ref: Build<31>-Footnote-173777650
Ref: Build<31>-Footnote-183777706
Ref: Build<31>-Footnote-193777762
Ref: Build<31>-Footnote-203777818
Ref: Build<31>-Footnote-213777874
Ref: Build<31>-Footnote-223777930
Ref: Build<31>-Footnote-233777986
Ref: Build<31>-Footnote-243778042
Ref: Build<31>-Footnote-253778098
Ref: Build<31>-Footnote-263778154
Ref: Build<31>-Footnote-273778210
Ref: Build<31>-Footnote-283778266
Ref: Build<31>-Footnote-293778322
Ref: Build<31>-Footnote-303778378
Ref: Build<31>-Footnote-313778434
Ref: Build<31>-Footnote-323778477
Ref: Build<31>-Footnote-333778533
Ref: Build<31>-Footnote-343778589
Ref: Build<31>-Footnote-353778645
Ref: Build<31>-Footnote-363778701
Node: Windows<27>3778767
Ref: whatsnew/changelog id3293778872
Ref: 191b3778872
Ref: Windows<27>-Footnote-13783295
Ref: Windows<27>-Footnote-23783350
Ref: Windows<27>-Footnote-33783405
Ref: Windows<27>-Footnote-43783460
Ref: Windows<27>-Footnote-53783515
Ref: Windows<27>-Footnote-63783570
Ref: Windows<27>-Footnote-73783625
Ref: Windows<27>-Footnote-83783680
Ref: Windows<27>-Footnote-93783735
Ref: Windows<27>-Footnote-103783790
Ref: Windows<27>-Footnote-113783846
Ref: Windows<27>-Footnote-123783902
Ref: Windows<27>-Footnote-133783958
Ref: Windows<27>-Footnote-143784014
Ref: Windows<27>-Footnote-153784070
Ref: Windows<27>-Footnote-163784126
Ref: Windows<27>-Footnote-173784182
Ref: Windows<27>-Footnote-183784238
Ref: Windows<27>-Footnote-193784294
Ref: Windows<27>-Footnote-203784350
Ref: Windows<27>-Footnote-213784406
Ref: Windows<27>-Footnote-223784462
Ref: Windows<27>-Footnote-233784518
Ref: Windows<27>-Footnote-243784574
Ref: Windows<27>-Footnote-253784630
Ref: Windows<27>-Footnote-263784686
Ref: Windows<27>-Footnote-273784752
Ref: Windows<27>-Footnote-283784808
Ref: Windows<27>-Footnote-293784874
Node: macOS<20>3784940
Ref: whatsnew/changelog id3303785044
Ref: 191d3785044
Ref: macOS<20>-Footnote-13785596
Node: IDLE<19>3785651
Ref: whatsnew/changelog id3313785759
Ref: 191e3785759
Ref: IDLE<19>-Footnote-13786674
Ref: IDLE<19>-Footnote-23786729
Ref: IDLE<19>-Footnote-33786784
Ref: IDLE<19>-Footnote-43786839
Ref: IDLE<19>-Footnote-53786894
Ref: IDLE<19>-Footnote-63786949
Ref: IDLE<19>-Footnote-73787004
Node: Tools/Demos<17>3787059
Ref: whatsnew/changelog id3323787167
Ref: 191f3787167
Ref: Tools/Demos<17>-Footnote-13788678
Ref: Tools/Demos<17>-Footnote-23788733
Ref: Tools/Demos<17>-Footnote-33788788
Ref: Tools/Demos<17>-Footnote-43788836
Ref: Tools/Demos<17>-Footnote-53788891
Ref: Tools/Demos<17>-Footnote-63788939
Ref: Tools/Demos<17>-Footnote-73788994
Ref: Tools/Demos<17>-Footnote-83789049
Ref: Tools/Demos<17>-Footnote-93789104
Ref: Tools/Demos<17>-Footnote-103789159
Ref: Tools/Demos<17>-Footnote-113789215
Ref: Tools/Demos<17>-Footnote-123789271
Node: C API<28>3789327
Ref: whatsnew/changelog id3343789418
Ref: 19203789418
Ref: C API<28>-Footnote-13796958
Ref: C API<28>-Footnote-23797013
Ref: C API<28>-Footnote-33797068
Ref: C API<28>-Footnote-43797123
Ref: C API<28>-Footnote-53797178
Ref: C API<28>-Footnote-63797233
Ref: C API<28>-Footnote-73797288
Ref: C API<28>-Footnote-83797343
Ref: C API<28>-Footnote-93797398
Ref: C API<28>-Footnote-103797453
Ref: C API<28>-Footnote-113797509
Ref: C API<28>-Footnote-123797565
Ref: C API<28>-Footnote-133797621
Ref: C API<28>-Footnote-143797677
Ref: C API<28>-Footnote-153797733
Ref: C API<28>-Footnote-163797789
Ref: C API<28>-Footnote-173797845
Ref: C API<28>-Footnote-183797901
Ref: C API<28>-Footnote-193797957
Ref: C API<28>-Footnote-203798013
Ref: C API<28>-Footnote-213798069
Ref: C API<28>-Footnote-223798125
Ref: C API<28>-Footnote-233798181
Ref: C API<28>-Footnote-243798237
Ref: C API<28>-Footnote-253798293
Ref: C API<28>-Footnote-263798349
Ref: C API<28>-Footnote-273798405
Ref: C API<28>-Footnote-283798461
Ref: C API<28>-Footnote-293798517
Ref: C API<28>-Footnote-303798573
Ref: C API<28>-Footnote-313798629
Ref: C API<28>-Footnote-323798685
Ref: C API<28>-Footnote-333798741
Ref: C API<28>-Footnote-343798797
Node: Python 3 11 0 beta 13798863
Ref: whatsnew/changelog python-3-11-0-beta-13798989
Ref: 19223798989
Node: Security<25>3799484
Ref: whatsnew/changelog id3353799583
Ref: 19233799583
Ref: Security<25>-Footnote-13799882
Node: Core and Builtins<61>3799937
Ref: whatsnew/changelog id3363800056
Ref: 19243800056
Ref: Core and Builtins<61>-Footnote-13806703
Ref: Core and Builtins<61>-Footnote-23806758
Ref: Core and Builtins<61>-Footnote-33806823
Ref: Core and Builtins<61>-Footnote-43806878
Ref: Core and Builtins<61>-Footnote-53806943
Ref: Core and Builtins<61>-Footnote-63806998
Ref: Core and Builtins<61>-Footnote-73807053
Ref: Core and Builtins<61>-Footnote-83807108
Ref: Core and Builtins<61>-Footnote-93807163
Ref: Core and Builtins<61>-Footnote-103807218
Ref: Core and Builtins<61>-Footnote-113807274
Ref: Core and Builtins<61>-Footnote-123807330
Ref: Core and Builtins<61>-Footnote-133807386
Ref: Core and Builtins<61>-Footnote-143807442
Ref: Core and Builtins<61>-Footnote-153807485
Ref: Core and Builtins<61>-Footnote-163807541
Ref: Core and Builtins<61>-Footnote-173807597
Ref: Core and Builtins<61>-Footnote-183807653
Ref: Core and Builtins<61>-Footnote-193807709
Ref: Core and Builtins<61>-Footnote-203807765
Ref: Core and Builtins<61>-Footnote-213807821
Ref: Core and Builtins<61>-Footnote-223807887
Ref: Core and Builtins<61>-Footnote-233807943
Ref: Core and Builtins<61>-Footnote-243807999
Ref: Core and Builtins<61>-Footnote-253808055
Ref: Core and Builtins<61>-Footnote-263808111
Ref: Core and Builtins<61>-Footnote-273808167
Ref: Core and Builtins<61>-Footnote-283808223
Ref: Core and Builtins<61>-Footnote-293808279
Ref: Core and Builtins<61>-Footnote-303808335
Ref: Core and Builtins<61>-Footnote-313808391
Ref: Core and Builtins<61>-Footnote-323808447
Ref: Core and Builtins<61>-Footnote-333808490
Ref: Core and Builtins<61>-Footnote-343808546
Ref: Core and Builtins<61>-Footnote-353808602
Ref: Core and Builtins<61>-Footnote-363808658
Ref: Core and Builtins<61>-Footnote-373808724
Ref: Core and Builtins<61>-Footnote-383808780
Ref: Core and Builtins<61>-Footnote-393808836
Ref: Core and Builtins<61>-Footnote-403808902
Node: Library<64>3808968
Ref: whatsnew/changelog id3373809096
Ref: 19273809096
Ref: Library<64>-Footnote-13809563
Node: Core and Builtins<62>3809628
Ref: whatsnew/changelog id3383809744
Ref: 19283809744
Ref: Core and Builtins<62>-Footnote-13811520
Ref: Core and Builtins<62>-Footnote-23811585
Ref: Core and Builtins<62>-Footnote-33811650
Ref: Core and Builtins<62>-Footnote-43811715
Ref: Core and Builtins<62>-Footnote-53811780
Ref: Core and Builtins<62>-Footnote-63811845
Ref: Core and Builtins<62>-Footnote-73811910
Ref: Core and Builtins<62>-Footnote-83811975
Ref: Core and Builtins<62>-Footnote-93812040
Node: Build<32>3812105
Ref: whatsnew/changelog id3393812231
Ref: 192c3812231
Ref: Build<32>-Footnote-13812358
Node: Core and Builtins<63>3812423
Ref: whatsnew/changelog id3403812539
Ref: 192d3812539
Ref: Core and Builtins<63>-Footnote-13813363
Ref: Core and Builtins<63>-Footnote-23813428
Ref: Core and Builtins<63>-Footnote-33813493
Node: Library<65>3813558
Ref: whatsnew/changelog id3413813682
Ref: 192e3813682
Ref: Library<65>-Footnote-13831232
Ref: Library<65>-Footnote-23831287
Ref: Library<65>-Footnote-33831342
Ref: Library<65>-Footnote-43831397
Ref: Library<65>-Footnote-53831452
Ref: Library<65>-Footnote-63831507
Ref: Library<65>-Footnote-73831562
Ref: Library<65>-Footnote-83831617
Ref: Library<65>-Footnote-93831672
Ref: Library<65>-Footnote-103831727
Ref: Library<65>-Footnote-113831783
Ref: Library<65>-Footnote-123831839
Ref: Library<65>-Footnote-133831895
Ref: Library<65>-Footnote-143831951
Ref: Library<65>-Footnote-153832007
Ref: Library<65>-Footnote-163832063
Ref: Library<65>-Footnote-173832119
Ref: Library<65>-Footnote-183832175
Ref: Library<65>-Footnote-193832231
Ref: Library<65>-Footnote-203832287
Ref: Library<65>-Footnote-213832343
Ref: Library<65>-Footnote-223832399
Ref: Library<65>-Footnote-233832455
Ref: Library<65>-Footnote-243832511
Ref: Library<65>-Footnote-253832577
Ref: Library<65>-Footnote-263832633
Ref: Library<65>-Footnote-273832689
Ref: Library<65>-Footnote-283832732
Ref: Library<65>-Footnote-293832788
Ref: Library<65>-Footnote-303832844
Ref: Library<65>-Footnote-313832900
Ref: Library<65>-Footnote-323832956
Ref: Library<65>-Footnote-333832999
Ref: Library<65>-Footnote-343833055
Ref: Library<65>-Footnote-353833111
Ref: Library<65>-Footnote-363833167
Ref: Library<65>-Footnote-373833223
Ref: Library<65>-Footnote-383833279
Ref: Library<65>-Footnote-393833335
Ref: Library<65>-Footnote-403833391
Ref: Library<65>-Footnote-413833447
Ref: Library<65>-Footnote-423833503
Ref: Library<65>-Footnote-433833559
Ref: Library<65>-Footnote-443833615
Ref: Library<65>-Footnote-453833671
Ref: Library<65>-Footnote-463833727
Ref: Library<65>-Footnote-473833783
Ref: Library<65>-Footnote-483833839
Ref: Library<65>-Footnote-493833895
Ref: Library<65>-Footnote-503833951
Ref: Library<65>-Footnote-513834007
Ref: Library<65>-Footnote-523834063
Ref: Library<65>-Footnote-533834119
Ref: Library<65>-Footnote-543834175
Ref: Library<65>-Footnote-553834231
Ref: Library<65>-Footnote-563834287
Ref: Library<65>-Footnote-573834353
Ref: Library<65>-Footnote-583834409
Ref: Library<65>-Footnote-593834465
Ref: Library<65>-Footnote-603834521
Ref: Library<65>-Footnote-613834577
Ref: Library<65>-Footnote-623834633
Ref: Library<65>-Footnote-633834689
Ref: Library<65>-Footnote-643834745
Ref: Library<65>-Footnote-653834801
Ref: Library<65>-Footnote-663834857
Ref: Library<65>-Footnote-673834900
Ref: Library<65>-Footnote-683834956
Ref: Library<65>-Footnote-693835012
Ref: Library<65>-Footnote-703835068
Ref: Library<65>-Footnote-713835124
Ref: Library<65>-Footnote-723835180
Ref: Library<65>-Footnote-733835236
Ref: Library<65>-Footnote-743835292
Ref: Library<65>-Footnote-753835348
Ref: Library<65>-Footnote-763835414
Ref: Library<65>-Footnote-773835470
Ref: Library<65>-Footnote-783835526
Ref: Library<65>-Footnote-793835582
Ref: Library<65>-Footnote-803835648
Ref: Library<65>-Footnote-813835714
Ref: Library<65>-Footnote-823835757
Ref: Library<65>-Footnote-833835823
Ref: Library<65>-Footnote-843835889
Ref: Library<65>-Footnote-853835955
Ref: Library<65>-Footnote-863836021
Ref: Library<65>-Footnote-873836087
Ref: Library<65>-Footnote-883836153
Ref: Library<65>-Footnote-893836219
Ref: Library<65>-Footnote-903836285
Ref: Library<65>-Footnote-913836351
Ref: Library<65>-Footnote-923836417
Ref: Library<65>-Footnote-933836483
Ref: Library<65>-Footnote-943836549
Ref: Library<65>-Footnote-953836615
Ref: Library<65>-Footnote-963836681
Ref: Library<65>-Footnote-973836747
Ref: Library<65>-Footnote-983836813
Ref: Library<65>-Footnote-993836879
Ref: Library<65>-Footnote-1003836945
Ref: Library<65>-Footnote-1013837012
Ref: Library<65>-Footnote-1023837079
Ref: Library<65>-Footnote-1033837146
Ref: Library<65>-Footnote-1043837213
Ref: Library<65>-Footnote-1053837280
Ref: Library<65>-Footnote-1063837347
Ref: Library<65>-Footnote-1073837414
Ref: Library<65>-Footnote-1083837481
Ref: Library<65>-Footnote-1093837548
Ref: Library<65>-Footnote-1103837615
Ref: Library<65>-Footnote-1113837682
Ref: Library<65>-Footnote-1123837749
Ref: Library<65>-Footnote-1133837816
Ref: Library<65>-Footnote-1143837883
Ref: Library<65>-Footnote-1153837950
Ref: Library<65>-Footnote-1163838017
Ref: Library<65>-Footnote-1173838084
Ref: Library<65>-Footnote-1183838151
Ref: Library<65>-Footnote-1193838218
Ref: Library<65>-Footnote-1203838285
Node: Documentation<27>3838352
Ref: whatsnew/changelog id3423838464
Ref: 193b3838464
Ref: Documentation<27>-Footnote-13840022
Ref: Documentation<27>-Footnote-23840077
Ref: Documentation<27>-Footnote-33840132
Ref: Documentation<27>-Footnote-43840187
Ref: Documentation<27>-Footnote-53840242
Ref: Documentation<27>-Footnote-63840307
Ref: Documentation<27>-Footnote-73840372
Ref: Documentation<27>-Footnote-83840437
Ref: Documentation<27>-Footnote-93840502
Ref: Documentation<27>-Footnote-103840544
Ref: Documentation<27>-Footnote-113840587
Ref: Documentation<27>-Footnote-123840653
Ref: Documentation<27>-Footnote-133840719
Ref: Documentation<27>-Footnote-143840784
Node: Tests<30>3840850
Ref: whatsnew/changelog id3433840960
Ref: 193e3840960
Ref: Tests<30>-Footnote-13842302
Ref: Tests<30>-Footnote-23842357
Ref: Tests<30>-Footnote-33842412
Ref: Tests<30>-Footnote-43842467
Ref: Tests<30>-Footnote-53842522
Ref: Tests<30>-Footnote-63842577
Ref: Tests<30>-Footnote-73842642
Ref: Tests<30>-Footnote-83842707
Node: Build<33>3842772
Ref: whatsnew/changelog id3443842876
Ref: 19413842876
Ref: Build<33>-Footnote-13843505
Ref: Build<33>-Footnote-23843560
Ref: Build<33>-Footnote-33843615
Ref: Build<33>-Footnote-43843680
Node: Windows<28>3843745
Ref: whatsnew/changelog id3453843849
Ref: 19423843849
Ref: Windows<28>-Footnote-13844485
Ref: Windows<28>-Footnote-23844550
Ref: Windows<28>-Footnote-33844615
Ref: Windows<28>-Footnote-43844680
Ref: Windows<28>-Footnote-53844745
Node: macOS<21>3844810
Ref: whatsnew/changelog id3463844920
Ref: 19433844920
Ref: macOS<21>-Footnote-13845052
Node: Tools/Demos<18>3845117
Ref: whatsnew/changelog id3473845225
Ref: 19443845225
Ref: Tools/Demos<18>-Footnote-13845784
Ref: Tools/Demos<18>-Footnote-23845839
Ref: Tools/Demos<18>-Footnote-33845894
Node: C API<29>3845949
Ref: whatsnew/changelog id3483846039
Ref: 19453846039
Ref: C API<29>-Footnote-13848202
Ref: C API<29>-Footnote-23848257
Ref: C API<29>-Footnote-33848312
Ref: C API<29>-Footnote-43848367
Ref: C API<29>-Footnote-53848422
Ref: C API<29>-Footnote-63848477
Ref: C API<29>-Footnote-73848519
Ref: C API<29>-Footnote-83848574
Ref: C API<29>-Footnote-93848629
Ref: C API<29>-Footnote-103848694
Ref: C API<29>-Footnote-113848760
Ref: C API<29>-Footnote-123848826
Ref: C API<29>-Footnote-133848892
Node: Python 3 11 0 alpha 73848958
Ref: whatsnew/changelog python-3-11-0-alpha-73849084
Ref: 19493849084
Node: Core and Builtins<64>3849559
Ref: whatsnew/changelog id3493849658
Ref: 194a3849658
Ref: Core and Builtins<64>-Footnote-13852931
Ref: Core and Builtins<64>-Footnote-23852996
Ref: Core and Builtins<64>-Footnote-33853061
Ref: Core and Builtins<64>-Footnote-43853126
Ref: Core and Builtins<64>-Footnote-53853191
Ref: Core and Builtins<64>-Footnote-63853256
Ref: Core and Builtins<64>-Footnote-73853321
Ref: Core and Builtins<64>-Footnote-83853386
Ref: Core and Builtins<64>-Footnote-93853451
Ref: Core and Builtins<64>-Footnote-103853516
Ref: Core and Builtins<64>-Footnote-113853582
Ref: Core and Builtins<64>-Footnote-123853648
Ref: Core and Builtins<64>-Footnote-133853714
Ref: Core and Builtins<64>-Footnote-143853780
Ref: Core and Builtins<64>-Footnote-153853846
Ref: Core and Builtins<64>-Footnote-163853912
Ref: Core and Builtins<64>-Footnote-173853978
Node: Library<66>3854044
Ref: whatsnew/changelog id3503854173
Ref: 194c3854173
Ref: Library<66>-Footnote-13854458
Node: Core and Builtins<65>3854523
Ref: whatsnew/changelog id3513854642
Ref: 194d3854642
Ref: Core and Builtins<65>-Footnote-13855493
Ref: Core and Builtins<65>-Footnote-23855558
Ref: Core and Builtins<65>-Footnote-33855623
Ref: Core and Builtins<65>-Footnote-43855688
Ref: Core and Builtins<65>-Footnote-53855753
Node: Library<67>3855818
Ref: whatsnew/changelog id3523855947
Ref: 194e3855947
Ref: Library<67>-Footnote-13856158
Node: Core and Builtins<66>3856223
Ref: whatsnew/changelog id3533856342
Ref: 19503856342
Ref: Core and Builtins<66>-Footnote-13857607
Ref: Core and Builtins<66>-Footnote-23857672
Ref: Core and Builtins<66>-Footnote-33857737
Ref: Core and Builtins<66>-Footnote-43857802
Ref: Core and Builtins<66>-Footnote-53857867
Ref: Core and Builtins<66>-Footnote-63857932
Ref: Core and Builtins<66>-Footnote-73857997
Ref: Core and Builtins<66>-Footnote-83858062
Ref: Core and Builtins<66>-Footnote-93858127
Node: Library<68>3858192
Ref: whatsnew/changelog id3543858317
Ref: 19523858317
Ref: Library<68>-Footnote-13872514
Ref: Library<68>-Footnote-23872579
Ref: Library<68>-Footnote-33872644
Ref: Library<68>-Footnote-43872709
Ref: Library<68>-Footnote-53872774
Ref: Library<68>-Footnote-63872839
Ref: Library<68>-Footnote-73872903
Ref: Library<68>-Footnote-83872968
Ref: Library<68>-Footnote-93873033
Ref: Library<68>-Footnote-103873098
Ref: Library<68>-Footnote-113873164
Ref: Library<68>-Footnote-123873230
Ref: Library<68>-Footnote-133873296
Ref: Library<68>-Footnote-143873362
Ref: Library<68>-Footnote-153873405
Ref: Library<68>-Footnote-163873471
Ref: Library<68>-Footnote-173873537
Ref: Library<68>-Footnote-183873603
Ref: Library<68>-Footnote-193873646
Ref: Library<68>-Footnote-203873712
Ref: Library<68>-Footnote-213873778
Ref: Library<68>-Footnote-223873844
Ref: Library<68>-Footnote-233873887
Ref: Library<68>-Footnote-243873953
Ref: Library<68>-Footnote-253874019
Ref: Library<68>-Footnote-263874085
Ref: Library<68>-Footnote-273874151
Ref: Library<68>-Footnote-283874217
Ref: Library<68>-Footnote-293874283
Ref: Library<68>-Footnote-303874350
Ref: Library<68>-Footnote-313874416
Ref: Library<68>-Footnote-323874482
Ref: Library<68>-Footnote-333874548
Ref: Library<68>-Footnote-343874614
Ref: Library<68>-Footnote-353874657
Ref: Library<68>-Footnote-363874723
Ref: Library<68>-Footnote-373874789
Ref: Library<68>-Footnote-383874854
Ref: Library<68>-Footnote-393874920
Ref: Library<68>-Footnote-403874986
Ref: Library<68>-Footnote-413875052
Ref: Library<68>-Footnote-423875118
Ref: Library<68>-Footnote-433875161
Ref: Library<68>-Footnote-443875227
Ref: Library<68>-Footnote-453875293
Ref: Library<68>-Footnote-463875359
Ref: Library<68>-Footnote-473875425
Ref: Library<68>-Footnote-483875491
Ref: Library<68>-Footnote-493875557
Ref: Library<68>-Footnote-503875623
Ref: Library<68>-Footnote-513875689
Ref: Library<68>-Footnote-523875755
Ref: Library<68>-Footnote-533875821
Ref: Library<68>-Footnote-543875887
Ref: Library<68>-Footnote-553875953
Ref: Library<68>-Footnote-563876019
Ref: Library<68>-Footnote-573876085
Ref: Library<68>-Footnote-583876151
Ref: Library<68>-Footnote-593876217
Ref: Library<68>-Footnote-603876260
Ref: Library<68>-Footnote-613876327
Ref: Library<68>-Footnote-623876393
Ref: Library<68>-Footnote-633876459
Ref: Library<68>-Footnote-643876525
Ref: Library<68>-Footnote-653876591
Ref: Library<68>-Footnote-663876657
Ref: Library<68>-Footnote-673876723
Ref: Library<68>-Footnote-683876789
Ref: Library<68>-Footnote-693876855
Ref: Library<68>-Footnote-703876921
Ref: Library<68>-Footnote-713876987
Ref: Library<68>-Footnote-723877053
Ref: Library<68>-Footnote-733877119
Ref: Library<68>-Footnote-743877185
Ref: Library<68>-Footnote-753877251
Ref: Library<68>-Footnote-763877317
Ref: Library<68>-Footnote-773877383
Ref: Library<68>-Footnote-783877449
Ref: Library<68>-Footnote-793877515
Ref: Library<68>-Footnote-803877581
Ref: Library<68>-Footnote-813877647
Ref: Library<68>-Footnote-823877713
Ref: Library<68>-Footnote-833877779
Ref: Library<68>-Footnote-843877822
Ref: Library<68>-Footnote-853877888
Ref: Library<68>-Footnote-863877954
Ref: Library<68>-Footnote-873878020
Ref: Library<68>-Footnote-883878086
Node: Documentation<28>3878152
Ref: whatsnew/changelog id3553878265
Ref: 195e3878265
Ref: Documentation<28>-Footnote-13879403
Ref: Documentation<28>-Footnote-23879468
Ref: Documentation<28>-Footnote-33879533
Ref: Documentation<28>-Footnote-43879575
Ref: Documentation<28>-Footnote-53879640
Ref: Documentation<28>-Footnote-63879705
Ref: Documentation<28>-Footnote-73879770
Ref: Documentation<28>-Footnote-83879835
Node: Tests<31>3879900
Ref: whatsnew/changelog id3563880011
Ref: 19613880011
Ref: Tests<31>-Footnote-13880980
Ref: Tests<31>-Footnote-23881045
Ref: Tests<31>-Footnote-33881110
Ref: Tests<31>-Footnote-43881175
Ref: Tests<31>-Footnote-53881240
Ref: Tests<31>-Footnote-63881305
Ref: Tests<31>-Footnote-73881370
Ref: Tests<31>-Footnote-83881435
Node: Build<34>3881477
Ref: whatsnew/changelog id3573881582
Ref: 19623881582
Ref: Build<34>-Footnote-13882870
Ref: Build<34>-Footnote-23882935
Ref: Build<34>-Footnote-33883000
Ref: Build<34>-Footnote-43883065
Ref: Build<34>-Footnote-53883130
Ref: Build<34>-Footnote-63883195
Ref: Build<34>-Footnote-73883260
Ref: Build<34>-Footnote-83883325
Ref: Build<34>-Footnote-93883390
Node: Windows<29>3883455
Ref: whatsnew/changelog id3583883560
Ref: 19643883560
Ref: Windows<29>-Footnote-13884753
Ref: Windows<29>-Footnote-23884818
Ref: Windows<29>-Footnote-33884874
Ref: Windows<29>-Footnote-43884939
Ref: Windows<29>-Footnote-53885004
Ref: Windows<29>-Footnote-63885046
Ref: Windows<29>-Footnote-73885111
Ref: Windows<29>-Footnote-83885176
Ref: Windows<29>-Footnote-93885241
Ref: Windows<29>-Footnote-103885296
Ref: Windows<29>-Footnote-113885353
Ref: Windows<29>-Footnote-123885419
Node: macOS<22>3885476
Ref: whatsnew/changelog id3593885587
Ref: 19653885587
Ref: macOS<22>-Footnote-13885925
Ref: macOS<22>-Footnote-23885990
Node: Tools/Demos<19>3886055
Ref: whatsnew/changelog id3603886164
Ref: 19663886164
Ref: Tools/Demos<19>-Footnote-13886371
Node: C API<30>3886436
Ref: whatsnew/changelog id3613886527
Ref: 19673886527
Ref: C API<30>-Footnote-13888786
Ref: C API<30>-Footnote-23888851
Ref: C API<30>-Footnote-33888916
Ref: C API<30>-Footnote-43888981
Ref: C API<30>-Footnote-53889046
Ref: C API<30>-Footnote-63889111
Ref: C API<30>-Footnote-73889176
Ref: C API<30>-Footnote-83889241
Node: Python 3 11 0 alpha 63889306
Ref: whatsnew/changelog python-3-11-0-alpha-63889433
Ref: 196a3889433
Node: Core and Builtins<67>3889942
Ref: whatsnew/changelog id3623890041
Ref: 196b3890041
Ref: Core and Builtins<67>-Footnote-13893427
Ref: Core and Builtins<67>-Footnote-23893492
Ref: Core and Builtins<67>-Footnote-33893557
Ref: Core and Builtins<67>-Footnote-43893622
Ref: Core and Builtins<67>-Footnote-53893687
Ref: Core and Builtins<67>-Footnote-63893752
Ref: Core and Builtins<67>-Footnote-73893817
Ref: Core and Builtins<67>-Footnote-83893882
Ref: Core and Builtins<67>-Footnote-93893947
Ref: Core and Builtins<67>-Footnote-103894012
Ref: Core and Builtins<67>-Footnote-113894078
Ref: Core and Builtins<67>-Footnote-123894144
Ref: Core and Builtins<67>-Footnote-133894210
Ref: Core and Builtins<67>-Footnote-143894276
Ref: Core and Builtins<67>-Footnote-153894342
Ref: Core and Builtins<67>-Footnote-163894408
Ref: Core and Builtins<67>-Footnote-173894474
Ref: Core and Builtins<67>-Footnote-183894540
Ref: Core and Builtins<67>-Footnote-193894606
Ref: Core and Builtins<67>-Footnote-203894672
Ref: Core and Builtins<67>-Footnote-213894738
Ref: Core and Builtins<67>-Footnote-223894804
Ref: Core and Builtins<67>-Footnote-233894870
Ref: Core and Builtins<67>-Footnote-243894936
Ref: Core and Builtins<67>-Footnote-253895002
Ref: Core and Builtins<67>-Footnote-263895068
Node: Library<69>3895134
Ref: whatsnew/changelog id3633895263
Ref: 196f3895263
Ref: Library<69>-Footnote-13895396
Node: Core and Builtins<68>3895461
Ref: whatsnew/changelog id3643895580
Ref: 19703895580
Ref: Core and Builtins<68>-Footnote-13897685
Ref: Core and Builtins<68>-Footnote-23897750
Ref: Core and Builtins<68>-Footnote-33897815
Ref: Core and Builtins<68>-Footnote-43897880
Ref: Core and Builtins<68>-Footnote-53897945
Ref: Core and Builtins<68>-Footnote-63898010
Ref: Core and Builtins<68>-Footnote-73898075
Ref: Core and Builtins<68>-Footnote-83898140
Ref: Core and Builtins<68>-Footnote-93898205
Ref: Core and Builtins<68>-Footnote-103898270
Ref: Core and Builtins<68>-Footnote-113898336
Node: Library<70>3898402
Ref: whatsnew/changelog id3653898531
Ref: 19713898531
Ref: Library<70>-Footnote-13898791
Node: Core and Builtins<69>3898856
Ref: whatsnew/changelog id3663898975
Ref: 19723898975
Ref: Core and Builtins<69>-Footnote-13899577
Ref: Core and Builtins<69>-Footnote-23899642
Ref: Core and Builtins<69>-Footnote-33899707
Ref: Core and Builtins<69>-Footnote-43899772
Node: Library<71>3899837
Ref: whatsnew/changelog id3673899966
Ref: 19733899966
Ref: Library<71>-Footnote-13900259
Ref: Library<71>-Footnote-23900324
Node: Core and Builtins<70>3900389
Ref: whatsnew/changelog id3683900508
Ref: 19743900508
Ref: Core and Builtins<70>-Footnote-13901207
Ref: Core and Builtins<70>-Footnote-23901272
Ref: Core and Builtins<70>-Footnote-33901337
Node: Library<72>3901402
Ref: whatsnew/changelog id3693901527
Ref: 19773901527
Ref: Library<72>-Footnote-13909739
Ref: Library<72>-Footnote-23909804
Ref: Library<72>-Footnote-33909869
Ref: Library<72>-Footnote-43909934
Ref: Library<72>-Footnote-53909999
Ref: Library<72>-Footnote-63910064
Ref: Library<72>-Footnote-73910129
Ref: Library<72>-Footnote-83910194
Ref: Library<72>-Footnote-93910259
Ref: Library<72>-Footnote-103910324
Ref: Library<72>-Footnote-113910390
Ref: Library<72>-Footnote-123910456
Ref: Library<72>-Footnote-133910522
Ref: Library<72>-Footnote-143910588
Ref: Library<72>-Footnote-153910654
Ref: Library<72>-Footnote-163910720
Ref: Library<72>-Footnote-173910786
Ref: Library<72>-Footnote-183910852
Ref: Library<72>-Footnote-193910918
Ref: Library<72>-Footnote-203910984
Ref: Library<72>-Footnote-213911050
Ref: Library<72>-Footnote-223911116
Ref: Library<72>-Footnote-233911182
Ref: Library<72>-Footnote-243911248
Ref: Library<72>-Footnote-253911314
Ref: Library<72>-Footnote-263911380
Ref: Library<72>-Footnote-273911446
Ref: Library<72>-Footnote-283911512
Ref: Library<72>-Footnote-293911578
Ref: Library<72>-Footnote-303911644
Ref: Library<72>-Footnote-313911710
Ref: Library<72>-Footnote-323911776
Ref: Library<72>-Footnote-333911842
Ref: Library<72>-Footnote-343911908
Ref: Library<72>-Footnote-353911951
Ref: Library<72>-Footnote-363912017
Ref: Library<72>-Footnote-373912083
Ref: Library<72>-Footnote-383912149
Ref: Library<72>-Footnote-393912215
Ref: Library<72>-Footnote-403912281
Ref: Library<72>-Footnote-413912347
Ref: Library<72>-Footnote-423912413
Ref: Library<72>-Footnote-433912479
Ref: Library<72>-Footnote-443912545
Ref: Library<72>-Footnote-453912611
Ref: Library<72>-Footnote-463912677
Ref: Library<72>-Footnote-473912743
Ref: Library<72>-Footnote-483912809
Node: Documentation<29>3912875
Ref: whatsnew/changelog id3703912988
Ref: 19823912988
Ref: Documentation<29>-Footnote-13913207
Node: Tests<32>3913272
Ref: whatsnew/changelog id3713913383
Ref: 19833913383
Ref: Tests<32>-Footnote-13914354
Ref: Tests<32>-Footnote-23914419
Ref: Tests<32>-Footnote-33914484
Ref: Tests<32>-Footnote-43914549
Ref: Tests<32>-Footnote-53914614
Node: Build<35>3914679
Ref: whatsnew/changelog id3723914784
Ref: 19843914784
Ref: Build<35>-Footnote-13916214
Ref: Build<35>-Footnote-23916279
Ref: Build<35>-Footnote-33916344
Ref: Build<35>-Footnote-43916409
Ref: Build<35>-Footnote-53916474
Ref: Build<35>-Footnote-63916539
Ref: Build<35>-Footnote-73916604
Node: Windows<30>3916669
Ref: whatsnew/changelog id3733916773
Ref: 19853916773
Ref: Windows<30>-Footnote-13917433
Ref: Windows<30>-Footnote-23917498
Ref: Windows<30>-Footnote-33917563
Node: IDLE<20>3917628
Ref: whatsnew/changelog id3743917732
Ref: 19863917732
Ref: IDLE<20>-Footnote-13918014
Ref: IDLE<20>-Footnote-23918079
Node: C API<31>3918144
Ref: whatsnew/changelog id3753918228
Ref: 19873918228
Ref: C API<31>-Footnote-13919177
Ref: C API<31>-Footnote-23919242
Ref: C API<31>-Footnote-33919307
Ref: C API<31>-Footnote-43919372
Ref: C API<31>-Footnote-53919437
Node: Python 3 11 0 alpha 53919502
Ref: whatsnew/changelog python-3-11-0-alpha-53919629
Ref: 19883919629
Node: Core and Builtins<71>3920110
Ref: whatsnew/changelog id3763920209
Ref: 19893920209
Ref: Core and Builtins<71>-Footnote-13924140
Ref: Core and Builtins<71>-Footnote-23924205
Ref: Core and Builtins<71>-Footnote-33924270
Ref: Core and Builtins<71>-Footnote-43924335
Ref: Core and Builtins<71>-Footnote-53924400
Ref: Core and Builtins<71>-Footnote-63924465
Ref: Core and Builtins<71>-Footnote-73924530
Ref: Core and Builtins<71>-Footnote-83924595
Ref: Core and Builtins<71>-Footnote-93924660
Ref: Core and Builtins<71>-Footnote-103924725
Ref: Core and Builtins<71>-Footnote-113924791
Ref: Core and Builtins<71>-Footnote-123924857
Ref: Core and Builtins<71>-Footnote-133924923
Ref: Core and Builtins<71>-Footnote-143924966
Ref: Core and Builtins<71>-Footnote-153925032
Ref: Core and Builtins<71>-Footnote-163925098
Ref: Core and Builtins<71>-Footnote-173925164
Ref: Core and Builtins<71>-Footnote-183925230
Ref: Core and Builtins<71>-Footnote-193925296
Node: Library<73>3925362
Ref: whatsnew/changelog id3773925491
Ref: 198b3925491
Ref: Library<73>-Footnote-13925711
Node: Core and Builtins<72>3925776
Ref: whatsnew/changelog id3783925895
Ref: 198c3925895
Ref: Core and Builtins<72>-Footnote-13926634
Ref: Core and Builtins<72>-Footnote-23926699
Ref: Core and Builtins<72>-Footnote-33926764
Ref: Core and Builtins<72>-Footnote-43926829
Node: Library<74>3926894
Ref: whatsnew/changelog id3793927011
Ref: 198e3927011
Ref: Library<74>-Footnote-13927139
Node: Build<36>3927204
Ref: whatsnew/changelog id3803927321
Ref: 198f3927321
Ref: Build<36>-Footnote-13927448
Node: Core and Builtins<73>3927513
Ref: whatsnew/changelog id3813927630
Ref: 19903927630
Ref: Core and Builtins<73>-Footnote-13927930
Node: Library<75>3927995
Ref: whatsnew/changelog id3823928120
Ref: 19913928120
Ref: Library<75>-Footnote-13934070
Ref: Library<75>-Footnote-23934135
Ref: Library<75>-Footnote-33934200
Ref: Library<75>-Footnote-43934265
Ref: Library<75>-Footnote-53934330
Ref: Library<75>-Footnote-63934395
Ref: Library<75>-Footnote-73934460
Ref: Library<75>-Footnote-83934525
Ref: Library<75>-Footnote-93934590
Ref: Library<75>-Footnote-103934655
Ref: Library<75>-Footnote-113934721
Ref: Library<75>-Footnote-123934787
Ref: Library<75>-Footnote-133934853
Ref: Library<75>-Footnote-143934919
Ref: Library<75>-Footnote-153934985
Ref: Library<75>-Footnote-163935051
Ref: Library<75>-Footnote-173935117
Ref: Library<75>-Footnote-183935183
Ref: Library<75>-Footnote-193935249
Ref: Library<75>-Footnote-203935315
Ref: Library<75>-Footnote-213935381
Ref: Library<75>-Footnote-223935447
Ref: Library<75>-Footnote-233935513
Ref: Library<75>-Footnote-243935579
Ref: Library<75>-Footnote-253935645
Ref: Library<75>-Footnote-263935711
Ref: Library<75>-Footnote-273935777
Ref: Library<75>-Footnote-283935843
Ref: Library<75>-Footnote-293935909
Ref: Library<75>-Footnote-303935975
Ref: Library<75>-Footnote-313936041
Ref: Library<75>-Footnote-323936107
Ref: Library<75>-Footnote-333936173
Ref: Library<75>-Footnote-343936239
Ref: Library<75>-Footnote-353936305
Ref: Library<75>-Footnote-363936371
Ref: Library<75>-Footnote-373936437
Node: Documentation<30>3936503
Ref: whatsnew/changelog id3833936616
Ref: 19973936616
Ref: Documentation<30>-Footnote-13936805
Node: Tests<33>3936870
Ref: whatsnew/changelog id3843936981
Ref: 19983936981
Ref: Tests<33>-Footnote-13939130
Ref: Tests<33>-Footnote-23939195
Ref: Tests<33>-Footnote-33939260
Ref: Tests<33>-Footnote-43939325
Ref: Tests<33>-Footnote-53939390
Ref: Tests<33>-Footnote-63939455
Ref: Tests<33>-Footnote-73939520
Ref: Tests<33>-Footnote-83939585
Ref: Tests<33>-Footnote-93939650
Ref: Tests<33>-Footnote-103939715
Ref: Tests<33>-Footnote-113939781
Node: Build<37>3939847
Ref: whatsnew/changelog id3853939952
Ref: 19993939952
Ref: Build<37>-Footnote-13941688
Ref: Build<37>-Footnote-23941753
Ref: Build<37>-Footnote-33941818
Ref: Build<37>-Footnote-43941883
Ref: Build<37>-Footnote-53941948
Ref: Build<37>-Footnote-63942013
Ref: Build<37>-Footnote-73942078
Ref: Build<37>-Footnote-83942143
Ref: Build<37>-Footnote-93942208
Ref: Build<37>-Footnote-103942273
Node: Windows<31>3942339
Ref: whatsnew/changelog id3863942444
Ref: 199a3942444
Ref: Windows<31>-Footnote-13942982
Ref: Windows<31>-Footnote-23943047
Ref: Windows<31>-Footnote-33943112
Node: macOS<23>3943177
Ref: whatsnew/changelog id3873943281
Ref: 199b3943281
Ref: macOS<23>-Footnote-13943413
Node: IDLE<21>3943478
Ref: whatsnew/changelog id3883943580
Ref: 199c3943580
Ref: IDLE<21>-Footnote-13944001
Node: C API<32>3944066
Ref: whatsnew/changelog id3893944150
Ref: 199d3944150
Ref: C API<32>-Footnote-13945043
Ref: C API<32>-Footnote-23945108
Ref: C API<32>-Footnote-33945173
Ref: C API<32>-Footnote-43945238
Ref: C API<32>-Footnote-53945303
Node: Python 3 11 0 alpha 43945368
Ref: whatsnew/changelog python-3-11-0-alpha-43945495
Ref: 199e3945495
Node: Core and Builtins<74>3946006
Ref: whatsnew/changelog id3903946105
Ref: 199f3946105
Ref: Core and Builtins<74>-Footnote-13948305
Ref: Core and Builtins<74>-Footnote-23948370
Ref: Core and Builtins<74>-Footnote-33948435
Ref: Core and Builtins<74>-Footnote-43948500
Ref: Core and Builtins<74>-Footnote-53948565
Ref: Core and Builtins<74>-Footnote-63948630
Ref: Core and Builtins<74>-Footnote-73948695
Ref: Core and Builtins<74>-Footnote-83948760
Ref: Core and Builtins<74>-Footnote-93948825
Ref: Core and Builtins<74>-Footnote-103948890
Ref: Core and Builtins<74>-Footnote-113948956
Node: Library<76>3949022
Ref: whatsnew/changelog id3913949151
Ref: 19a13949151
Ref: Library<76>-Footnote-13949352
Node: Core and Builtins<75>3949417
Ref: whatsnew/changelog id3923949536
Ref: 19a23949536
Ref: Core and Builtins<75>-Footnote-13950263
Ref: Core and Builtins<75>-Footnote-23950328
Ref: Core and Builtins<75>-Footnote-33950393
Ref: Core and Builtins<75>-Footnote-43950458
Ref: Core and Builtins<75>-Footnote-53950523
Node: Library<77>3950588
Ref: whatsnew/changelog id3933950717
Ref: 19a33950717
Ref: Library<77>-Footnote-13950861
Node: Core and Builtins<76>3950926
Ref: whatsnew/changelog id3943951045
Ref: 19a43951045
Ref: Core and Builtins<76>-Footnote-13953592
Ref: Core and Builtins<76>-Footnote-23953657
Ref: Core and Builtins<76>-Footnote-33953722
Ref: Core and Builtins<76>-Footnote-43953787
Ref: Core and Builtins<76>-Footnote-53953852
Ref: Core and Builtins<76>-Footnote-63953917
Ref: Core and Builtins<76>-Footnote-73953982
Ref: Core and Builtins<76>-Footnote-83954047
Ref: Core and Builtins<76>-Footnote-93954112
Ref: Core and Builtins<76>-Footnote-103954177
Ref: Core and Builtins<76>-Footnote-113954243
Ref: Core and Builtins<76>-Footnote-123954309
Ref: Core and Builtins<76>-Footnote-133954375
Ref: Core and Builtins<76>-Footnote-143954441
Ref: Core and Builtins<76>-Footnote-153954507
Node: Library<78>3954573
Ref: whatsnew/changelog id3953954702
Ref: 19a53954702
Ref: Library<78>-Footnote-13954874
Node: Core and Builtins<77>3954939
Ref: whatsnew/changelog id3963955058
Ref: 19a63955058
Ref: Core and Builtins<77>-Footnote-13956339
Ref: Core and Builtins<77>-Footnote-23956404
Ref: Core and Builtins<77>-Footnote-33956469
Ref: Core and Builtins<77>-Footnote-43956534
Ref: Core and Builtins<77>-Footnote-53956599
Ref: Core and Builtins<77>-Footnote-63956641
Ref: Core and Builtins<77>-Footnote-73956706
Node: Library<79>3956771
Ref: whatsnew/changelog id3973956896
Ref: 19a73956896
Ref: Library<79>-Footnote-13964177
Ref: Library<79>-Footnote-23964242
Ref: Library<79>-Footnote-33964307
Ref: Library<79>-Footnote-43964372
Ref: Library<79>-Footnote-53964437
Ref: Library<79>-Footnote-63964502
Ref: Library<79>-Footnote-73964567
Ref: Library<79>-Footnote-83964632
Ref: Library<79>-Footnote-93964697
Ref: Library<79>-Footnote-103964762
Ref: Library<79>-Footnote-113964828
Ref: Library<79>-Footnote-123964894
Ref: Library<79>-Footnote-133964960
Ref: Library<79>-Footnote-143965026
Ref: Library<79>-Footnote-153965092
Ref: Library<79>-Footnote-163965158
Ref: Library<79>-Footnote-173965224
Ref: Library<79>-Footnote-183965290
Ref: Library<79>-Footnote-193965356
Ref: Library<79>-Footnote-203965422
Ref: Library<79>-Footnote-213965488
Ref: Library<79>-Footnote-223965554
Ref: Library<79>-Footnote-233965620
Ref: Library<79>-Footnote-243965686
Ref: Library<79>-Footnote-253965752
Ref: Library<79>-Footnote-263965818
Ref: Library<79>-Footnote-273965884
Ref: Library<79>-Footnote-283965950
Ref: Library<79>-Footnote-293966016
Ref: Library<79>-Footnote-303966082
Ref: Library<79>-Footnote-313966148
Ref: Library<79>-Footnote-323966214
Ref: Library<79>-Footnote-333966280
Ref: Library<79>-Footnote-343966346
Ref: Library<79>-Footnote-353966412
Ref: Library<79>-Footnote-363966478
Ref: Library<79>-Footnote-373966544
Ref: Library<79>-Footnote-383966610
Ref: Library<79>-Footnote-393966676
Ref: Library<79>-Footnote-403966742
Ref: Library<79>-Footnote-413966808
Ref: Library<79>-Footnote-423966874
Ref: Library<79>-Footnote-433966940
Ref: Library<79>-Footnote-443967006
Node: Documentation<31>3967072
Ref: whatsnew/changelog id3983967185
Ref: 19ac3967185
Ref: Documentation<31>-Footnote-13967682
Ref: Documentation<31>-Footnote-23967747
Ref: Documentation<31>-Footnote-33967812
Ref: Documentation<31>-Footnote-43967877
Node: Tests<34>3967942
Ref: whatsnew/changelog id3993968053
Ref: 19af3968053
Ref: Tests<34>-Footnote-13968983
Ref: Tests<34>-Footnote-23969048
Ref: Tests<34>-Footnote-33969113
Ref: Tests<34>-Footnote-43969178
Ref: Tests<34>-Footnote-53969243
Ref: Tests<34>-Footnote-63969308
Ref: Tests<34>-Footnote-73969373
Ref: Tests<34>-Footnote-83969438
Node: Build<38>3969503
Ref: whatsnew/changelog id4003969608
Ref: 19b03969608
Ref: Build<38>-Footnote-13971672
Ref: Build<38>-Footnote-23971737
Ref: Build<38>-Footnote-33971802
Ref: Build<38>-Footnote-43971867
Ref: Build<38>-Footnote-53971932
Ref: Build<38>-Footnote-63971997
Ref: Build<38>-Footnote-73972062
Ref: Build<38>-Footnote-83972127
Ref: Build<38>-Footnote-93972192
Ref: Build<38>-Footnote-103972257
Ref: Build<38>-Footnote-113972323
Ref: Build<38>-Footnote-123972389
Node: Windows<32>3972455
Ref: whatsnew/changelog id4013972560
Ref: 19b13972560
Ref: Windows<32>-Footnote-13972781
Node: macOS<24>3972846
Ref: whatsnew/changelog id4023972951
Ref: 19b23972951
Ref: macOS<24>-Footnote-13973191
Node: C API<33>3973256
Ref: whatsnew/changelog id4033973341
Ref: 19b33973341
Ref: C API<33>-Footnote-13974602
Ref: C API<33>-Footnote-23974667
Ref: C API<33>-Footnote-33974732
Ref: C API<33>-Footnote-43974797
Ref: C API<33>-Footnote-53974862
Node: Python 3 11 0 alpha 33974927
Ref: whatsnew/changelog python-3-11-0-alpha-33975054
Ref: 19b53975054
Node: Core and Builtins<78>3975429
Ref: whatsnew/changelog id4043975528
Ref: 19b63975528
Ref: Core and Builtins<78>-Footnote-13978113
Ref: Core and Builtins<78>-Footnote-23978178
Ref: Core and Builtins<78>-Footnote-33978243
Ref: Core and Builtins<78>-Footnote-43978308
Ref: Core and Builtins<78>-Footnote-53978373
Ref: Core and Builtins<78>-Footnote-63978438
Ref: Core and Builtins<78>-Footnote-73978503
Ref: Core and Builtins<78>-Footnote-83978568
Ref: Core and Builtins<78>-Footnote-93978633
Ref: Core and Builtins<78>-Footnote-103978698
Ref: Core and Builtins<78>-Footnote-113978764
Ref: Core and Builtins<78>-Footnote-123978830
Node: Library<80>3978896
Ref: whatsnew/changelog id4053979025
Ref: 19b83979025
Ref: Library<80>-Footnote-13979197
Node: Core and Builtins<79>3979262
Ref: whatsnew/changelog id4063979381
Ref: 19b93979381
Ref: Core and Builtins<79>-Footnote-13982410
Ref: Core and Builtins<79>-Footnote-23982475
Ref: Core and Builtins<79>-Footnote-33982540
Ref: Core and Builtins<79>-Footnote-43982605
Ref: Core and Builtins<79>-Footnote-53982670
Ref: Core and Builtins<79>-Footnote-63982735
Ref: Core and Builtins<79>-Footnote-73982800
Ref: Core and Builtins<79>-Footnote-83982865
Ref: Core and Builtins<79>-Footnote-93982930
Ref: Core and Builtins<79>-Footnote-103982972
Ref: Core and Builtins<79>-Footnote-113983038
Ref: Core and Builtins<79>-Footnote-123983104
Ref: Core and Builtins<79>-Footnote-133983170
Ref: Core and Builtins<79>-Footnote-143983236
Ref: Core and Builtins<79>-Footnote-153983302
Ref: Core and Builtins<79>-Footnote-163983368
Ref: Core and Builtins<79>-Footnote-173983434
Ref: Core and Builtins<79>-Footnote-183983500
Ref: Core and Builtins<79>-Footnote-193983566
Ref: Core and Builtins<79>-Footnote-203983632
Ref: Core and Builtins<79>-Footnote-213983698
Node: Library<81>3983764
Ref: whatsnew/changelog id4073983889
Ref: 19ba3983889
Ref: Library<81>-Footnote-13989858
Ref: Library<81>-Footnote-23989923
Ref: Library<81>-Footnote-33989988
Ref: Library<81>-Footnote-43990053
Ref: Library<81>-Footnote-53990118
Ref: Library<81>-Footnote-63990183
Ref: Library<81>-Footnote-73990248
Ref: Library<81>-Footnote-83990313
Ref: Library<81>-Footnote-93990378
Ref: Library<81>-Footnote-103990443
Ref: Library<81>-Footnote-113990509
Ref: Library<81>-Footnote-123990575
Ref: Library<81>-Footnote-133990641
Ref: Library<81>-Footnote-143990707
Ref: Library<81>-Footnote-153990773
Ref: Library<81>-Footnote-163990839
Ref: Library<81>-Footnote-173990905
Ref: Library<81>-Footnote-183990971
Ref: Library<81>-Footnote-193991037
Ref: Library<81>-Footnote-203991103
Ref: Library<81>-Footnote-213991169
Ref: Library<81>-Footnote-223991235
Ref: Library<81>-Footnote-233991301
Ref: Library<81>-Footnote-243991367
Ref: Library<81>-Footnote-253991433
Ref: Library<81>-Footnote-263991499
Ref: Library<81>-Footnote-273991565
Ref: Library<81>-Footnote-283991631
Ref: Library<81>-Footnote-293991697
Ref: Library<81>-Footnote-303991763
Ref: Library<81>-Footnote-313991829
Ref: Library<81>-Footnote-323991872
Ref: Library<81>-Footnote-333991938
Ref: Library<81>-Footnote-343992004
Ref: Library<81>-Footnote-353992070
Ref: Library<81>-Footnote-363992136
Node: Documentation<32>3992202
Ref: whatsnew/changelog id4083992315
Ref: 19bc3992315
Ref: Documentation<32>-Footnote-13993623
Ref: Documentation<32>-Footnote-23993688
Ref: Documentation<32>-Footnote-33993753
Ref: Documentation<32>-Footnote-43993818
Ref: Documentation<32>-Footnote-53993883
Ref: Documentation<32>-Footnote-63993948
Ref: Documentation<32>-Footnote-73994013
Ref: Documentation<32>-Footnote-83994078
Ref: Documentation<32>-Footnote-93994143
Node: Tests<35>3994208
Ref: whatsnew/changelog id4093994319
Ref: 19bd3994319
Ref: Tests<35>-Footnote-13995130
Ref: Tests<35>-Footnote-23995195
Ref: Tests<35>-Footnote-33995260
Ref: Tests<35>-Footnote-43995325
Ref: Tests<35>-Footnote-53995390
Ref: Tests<35>-Footnote-63995455
Node: Build<39>3995520
Ref: whatsnew/changelog id4103995625
Ref: 19be3995625
Ref: Build<39>-Footnote-14001424
Ref: Build<39>-Footnote-24001489
Ref: Build<39>-Footnote-34001554
Ref: Build<39>-Footnote-44001619
Ref: Build<39>-Footnote-54001684
Ref: Build<39>-Footnote-64001749
Ref: Build<39>-Footnote-74001814
Ref: Build<39>-Footnote-84001879
Ref: Build<39>-Footnote-94001944
Ref: Build<39>-Footnote-104002009
Ref: Build<39>-Footnote-114002075
Ref: Build<39>-Footnote-124002141
Ref: Build<39>-Footnote-134002207
Ref: Build<39>-Footnote-144002273
Ref: Build<39>-Footnote-154002339
Ref: Build<39>-Footnote-164002405
Ref: Build<39>-Footnote-174002471
Ref: Build<39>-Footnote-184002537
Ref: Build<39>-Footnote-194002603
Ref: Build<39>-Footnote-204002669
Ref: Build<39>-Footnote-214002735
Ref: Build<39>-Footnote-224002801
Ref: Build<39>-Footnote-234002867
Ref: Build<39>-Footnote-244002933
Ref: Build<39>-Footnote-254002999
Ref: Build<39>-Footnote-264003065
Ref: Build<39>-Footnote-274003131
Ref: Build<39>-Footnote-284003197
Ref: Build<39>-Footnote-294003263
Ref: Build<39>-Footnote-304003329
Ref: Build<39>-Footnote-314003395
Ref: Build<39>-Footnote-324003461
Ref: Build<39>-Footnote-334003527
Node: Windows<33>4003593
Ref: whatsnew/changelog id4114003698
Ref: 19bf4003698
Ref: Windows<33>-Footnote-14004889
Ref: Windows<33>-Footnote-24004954
Ref: Windows<33>-Footnote-34005019
Ref: Windows<33>-Footnote-44005084
Ref: Windows<33>-Footnote-54005149
Ref: Windows<33>-Footnote-64005214
Node: macOS<25>4005279
Ref: whatsnew/changelog id4124005384
Ref: 19c04005384
Ref: macOS<25>-Footnote-14005534
Node: C API<34>4005599
Ref: whatsnew/changelog id4134005684
Ref: 19c14005684
Ref: C API<34>-Footnote-14005891
Node: Python 3 11 0 alpha 24005956
Ref: whatsnew/changelog python-3-11-0-alpha-24006083
Ref: 19c24006083
Node: Core and Builtins<80>4006408
Ref: whatsnew/changelog id4144006507
Ref: 19c34006507
Ref: Core and Builtins<80>-Footnote-14011882
Ref: Core and Builtins<80>-Footnote-24011947
Ref: Core and Builtins<80>-Footnote-34012012
Ref: Core and Builtins<80>-Footnote-44012077
Ref: Core and Builtins<80>-Footnote-54012142
Ref: Core and Builtins<80>-Footnote-64012207
Ref: Core and Builtins<80>-Footnote-74012272
Ref: Core and Builtins<80>-Footnote-84012337
Ref: Core and Builtins<80>-Footnote-94012402
Ref: Core and Builtins<80>-Footnote-104012467
Ref: Core and Builtins<80>-Footnote-114012533
Ref: Core and Builtins<80>-Footnote-124012599
Ref: Core and Builtins<80>-Footnote-134012665
Ref: Core and Builtins<80>-Footnote-144012731
Ref: Core and Builtins<80>-Footnote-154012797
Ref: Core and Builtins<80>-Footnote-164012863
Ref: Core and Builtins<80>-Footnote-174012929
Ref: Core and Builtins<80>-Footnote-184012995
Ref: Core and Builtins<80>-Footnote-194013061
Ref: Core and Builtins<80>-Footnote-204013127
Ref: Core and Builtins<80>-Footnote-214013170
Ref: Core and Builtins<80>-Footnote-224013236
Ref: Core and Builtins<80>-Footnote-234013302
Ref: Core and Builtins<80>-Footnote-244013368
Ref: Core and Builtins<80>-Footnote-254013434
Ref: Core and Builtins<80>-Footnote-264013500
Node: Library<82>4013543
Ref: whatsnew/changelog id4154013668
Ref: 19c54013668
Ref: Library<82>-Footnote-14021236
Ref: Library<82>-Footnote-24021301
Ref: Library<82>-Footnote-34021366
Ref: Library<82>-Footnote-44021431
Ref: Library<82>-Footnote-54021496
Ref: Library<82>-Footnote-64021561
Ref: Library<82>-Footnote-74021626
Ref: Library<82>-Footnote-84021691
Ref: Library<82>-Footnote-94021756
Ref: Library<82>-Footnote-104021821
Ref: Library<82>-Footnote-114021887
Ref: Library<82>-Footnote-124021953
Ref: Library<82>-Footnote-134022019
Ref: Library<82>-Footnote-144022085
Ref: Library<82>-Footnote-154022151
Ref: Library<82>-Footnote-164022217
Ref: Library<82>-Footnote-174022283
Ref: Library<82>-Footnote-184022349
Ref: Library<82>-Footnote-194022415
Ref: Library<82>-Footnote-204022481
Ref: Library<82>-Footnote-214022547
Ref: Library<82>-Footnote-224022613
Ref: Library<82>-Footnote-234022679
Ref: Library<82>-Footnote-244022745
Ref: Library<82>-Footnote-254022811
Ref: Library<82>-Footnote-264022877
Ref: Library<82>-Footnote-274022943
Ref: Library<82>-Footnote-284023009
Ref: Library<82>-Footnote-294023075
Ref: Library<82>-Footnote-304023141
Ref: Library<82>-Footnote-314023207
Ref: Library<82>-Footnote-324023273
Ref: Library<82>-Footnote-334023339
Ref: Library<82>-Footnote-344023405
Ref: Library<82>-Footnote-354023471
Ref: Library<82>-Footnote-364023537
Ref: Library<82>-Footnote-374023603
Ref: Library<82>-Footnote-384023669
Ref: Library<82>-Footnote-394023735
Ref: Library<82>-Footnote-404023801
Ref: Library<82>-Footnote-414023867
Ref: Library<82>-Footnote-424023933
Ref: Library<82>-Footnote-434023999
Ref: Library<82>-Footnote-444024059
Ref: Library<82>-Footnote-454024125
Node: Documentation<33>4024191
Ref: whatsnew/changelog id4164024304
Ref: 19ca4024304
Ref: Documentation<33>-Footnote-14025800
Ref: Documentation<33>-Footnote-24025865
Ref: Documentation<33>-Footnote-34025930
Ref: Documentation<33>-Footnote-44025995
Ref: Documentation<33>-Footnote-54026060
Ref: Documentation<33>-Footnote-64026125
Ref: Documentation<33>-Footnote-74026190
Ref: Documentation<33>-Footnote-84026255
Ref: Documentation<33>-Footnote-94026320
Ref: Documentation<33>-Footnote-104026362
Ref: Documentation<33>-Footnote-114026428
Node: Tests<36>4026494
Ref: whatsnew/changelog id4174026605
Ref: 19ce4026605
Ref: Tests<36>-Footnote-14028879
Ref: Tests<36>-Footnote-24028944
Ref: Tests<36>-Footnote-34029009
Ref: Tests<36>-Footnote-44029074
Ref: Tests<36>-Footnote-54029139
Ref: Tests<36>-Footnote-64029204
Ref: Tests<36>-Footnote-74029269
Ref: Tests<36>-Footnote-84029334
Ref: Tests<36>-Footnote-94029399
Ref: Tests<36>-Footnote-104029464
Ref: Tests<36>-Footnote-114029530
Ref: Tests<36>-Footnote-124029596
Ref: Tests<36>-Footnote-134029662
Node: Build<40>4029728
Ref: whatsnew/changelog id4184029833
Ref: 19cf4029833
Ref: Build<40>-Footnote-14032510
Ref: Build<40>-Footnote-24032575
Ref: Build<40>-Footnote-34032640
Ref: Build<40>-Footnote-44032705
Ref: Build<40>-Footnote-54032770
Ref: Build<40>-Footnote-64032835
Ref: Build<40>-Footnote-74032900
Ref: Build<40>-Footnote-84032965
Ref: Build<40>-Footnote-94033030
Ref: Build<40>-Footnote-104033095
Ref: Build<40>-Footnote-114033161
Ref: Build<40>-Footnote-124033227
Ref: Build<40>-Footnote-134033293
Ref: Build<40>-Footnote-144033359
Ref: Build<40>-Footnote-154033425
Node: Windows<34>4033491
Ref: whatsnew/changelog id4194033596
Ref: 19d04033596
Ref: Windows<34>-Footnote-14034151
Ref: Windows<34>-Footnote-24034216
Ref: Windows<34>-Footnote-34034281
Node: macOS<26>4034346
Ref: whatsnew/changelog id4204034450
Ref: 19d14034450
Ref: macOS<26>-Footnote-14034711
Node: IDLE<22>4034776
Ref: whatsnew/changelog id4214034878
Ref: 19d24034878
Ref: IDLE<22>-Footnote-14035039
Node: C API<35>4035104
Ref: whatsnew/changelog id4224035188
Ref: 19d34035188
Ref: C API<35>-Footnote-14038918
Ref: C API<35>-Footnote-24038983
Ref: C API<35>-Footnote-34039048
Ref: C API<35>-Footnote-44039113
Ref: C API<35>-Footnote-54039178
Ref: C API<35>-Footnote-64039243
Ref: C API<35>-Footnote-74039308
Ref: C API<35>-Footnote-84039373
Ref: C API<35>-Footnote-94039438
Ref: C API<35>-Footnote-104039503
Ref: C API<35>-Footnote-114039569
Ref: C API<35>-Footnote-124039635
Ref: C API<35>-Footnote-134039701
Ref: C API<35>-Footnote-144039767
Node: Python 3 11 0 alpha 14039833
Ref: whatsnew/changelog python-3-11-0-alpha-14039959
Ref: 19d44039959
Node: Security<26>4040954
Ref: whatsnew/changelog id4234041054
Ref: 19d54041054
Ref: Security<26>-Footnote-14042413
Ref: Security<26>-Footnote-24042478
Ref: Security<26>-Footnote-34042543
Ref: Security<26>-Footnote-44042608
Ref: Security<26>-Footnote-54042673
Ref: Security<26>-Footnote-64042728
Ref: Security<26>-Footnote-74042793
Node: Core and Builtins<81>4042858
Ref: whatsnew/changelog id4244042978
Ref: 19d74042978
Ref: Core and Builtins<81>-Footnote-14044082
Ref: Core and Builtins<81>-Footnote-24044147
Ref: Core and Builtins<81>-Footnote-34044212
Ref: Core and Builtins<81>-Footnote-44044277
Ref: Core and Builtins<81>-Footnote-54044342
Ref: Core and Builtins<81>-Footnote-64044407
Node: Library<83>4044472
Ref: whatsnew/changelog id4254044601
Ref: 19d94044601
Ref: Library<83>-Footnote-14045093
Ref: Library<83>-Footnote-24045158
Node: Core and Builtins<82>4045223
Ref: whatsnew/changelog id4264045342
Ref: 19dc4045342
Ref: Core and Builtins<82>-Footnote-14045527
Node: Library<84>4045592
Ref: whatsnew/changelog id4274045721
Ref: 19dd4045721
Ref: Library<84>-Footnote-14045976
Node: Core and Builtins<83>4046041
Ref: whatsnew/changelog id4284046160
Ref: 19de4046160
Ref: Core and Builtins<83>-Footnote-14049006
Ref: Core and Builtins<83>-Footnote-24049071
Ref: Core and Builtins<83>-Footnote-34049136
Ref: Core and Builtins<83>-Footnote-44049203
Ref: Core and Builtins<83>-Footnote-54049268
Ref: Core and Builtins<83>-Footnote-64049333
Ref: Core and Builtins<83>-Footnote-74049398
Ref: Core and Builtins<83>-Footnote-84049463
Ref: Core and Builtins<83>-Footnote-94049528
Node: Library<85>4049593
Ref: whatsnew/changelog id4294049722
Ref: 19df4049722
Ref: Library<85>-Footnote-14049995
Node: Core and Builtins<84>4050060
Ref: whatsnew/changelog id4304050179
Ref: 19e04050179
Ref: Core and Builtins<84>-Footnote-14050638
Ref: Core and Builtins<84>-Footnote-24050703
Ref: Core and Builtins<84>-Footnote-34050768
Node: Library<86>4050833
Ref: whatsnew/changelog id4314050962
Ref: 19e14050962
Ref: Library<86>-Footnote-14051301
Node: Core and Builtins<85>4051366
Ref: whatsnew/changelog id4324051485
Ref: 19e24051485
Ref: Core and Builtins<85>-Footnote-14052499
Ref: Core and Builtins<85>-Footnote-24052564
Ref: Core and Builtins<85>-Footnote-34052629
Ref: Core and Builtins<85>-Footnote-44052694
Ref: Core and Builtins<85>-Footnote-54052759
Node: Library<87>4052824
Ref: whatsnew/changelog id4334052953
Ref: 19e34052953
Ref: Library<87>-Footnote-14053151
Node: Core and Builtins<86>4053216
Ref: whatsnew/changelog id4344053335
Ref: 19e44053335
Ref: Core and Builtins<86>-Footnote-14058375
Ref: Core and Builtins<86>-Footnote-24058440
Ref: Core and Builtins<86>-Footnote-34058505
Ref: Core and Builtins<86>-Footnote-44058570
Ref: Core and Builtins<86>-Footnote-54058635
Ref: Core and Builtins<86>-Footnote-64058700
Ref: Core and Builtins<86>-Footnote-74058765
Ref: Core and Builtins<86>-Footnote-84058830
Ref: Core and Builtins<86>-Footnote-94058895
Ref: Core and Builtins<86>-Footnote-104058960
Ref: Core and Builtins<86>-Footnote-114059026
Ref: Core and Builtins<86>-Footnote-124059092
Ref: Core and Builtins<86>-Footnote-134059158
Ref: Core and Builtins<86>-Footnote-144059224
Ref: Core and Builtins<86>-Footnote-154059290
Ref: Core and Builtins<86>-Footnote-164059356
Ref: Core and Builtins<86>-Footnote-174059422
Ref: Core and Builtins<86>-Footnote-184059488
Ref: Core and Builtins<86>-Footnote-194059554
Ref: Core and Builtins<86>-Footnote-204059620
Ref: Core and Builtins<86>-Footnote-214059686
Ref: Core and Builtins<86>-Footnote-224059752
Ref: Core and Builtins<86>-Footnote-234059818
Ref: Core and Builtins<86>-Footnote-244059884
Ref: Core and Builtins<86>-Footnote-254059950
Ref: Core and Builtins<86>-Footnote-264060016
Ref: Core and Builtins<86>-Footnote-274060082
Ref: Core and Builtins<86>-Footnote-284060148
Ref: Core and Builtins<86>-Footnote-294060214
Ref: Core and Builtins<86>-Footnote-304060280
Ref: Core and Builtins<86>-Footnote-314060346
Ref: Core and Builtins<86>-Footnote-324060412
Node: Library<88>4060478
Ref: whatsnew/changelog id4354060607
Ref: 19e64060607
Ref: Library<88>-Footnote-14060874
Node: Core and Builtins<87>4060939
Ref: whatsnew/changelog id4364061058
Ref: 19e74061058
Ref: Core and Builtins<87>-Footnote-14062902
Ref: Core and Builtins<87>-Footnote-24062967
Ref: Core and Builtins<87>-Footnote-34063032
Ref: Core and Builtins<87>-Footnote-44063097
Ref: Core and Builtins<87>-Footnote-54063162
Ref: Core and Builtins<87>-Footnote-64063227
Ref: Core and Builtins<87>-Footnote-74063292
Ref: Core and Builtins<87>-Footnote-84063357
Ref: Core and Builtins<87>-Footnote-94063422
Node: Library<89>4063487
Ref: whatsnew/changelog id4374063616
Ref: 19e84063616
Ref: Library<89>-Footnote-14063942
Node: Core and Builtins<88>4064007
Ref: whatsnew/changelog id4384064126
Ref: 19e94064126
Ref: Core and Builtins<88>-Footnote-14064659
Ref: Core and Builtins<88>-Footnote-24064724
Ref: Core and Builtins<88>-Footnote-34064766
Node: Library<90>4064831
Ref: whatsnew/changelog id4394064960
Ref: 19ea4064960
Ref: Library<90>-Footnote-14065270
Node: Core and Builtins<89>4065335
Ref: whatsnew/changelog id4404065454
Ref: 19eb4065454
Ref: Core and Builtins<89>-Footnote-14069220
Ref: Core and Builtins<89>-Footnote-24069285
Ref: Core and Builtins<89>-Footnote-34069327
Ref: Core and Builtins<89>-Footnote-44069392
Ref: Core and Builtins<89>-Footnote-54069457
Ref: Core and Builtins<89>-Footnote-64069522
Ref: Core and Builtins<89>-Footnote-74069587
Ref: Core and Builtins<89>-Footnote-84069652
Ref: Core and Builtins<89>-Footnote-94069717
Ref: Core and Builtins<89>-Footnote-104069782
Ref: Core and Builtins<89>-Footnote-114069848
Ref: Core and Builtins<89>-Footnote-124069914
Ref: Core and Builtins<89>-Footnote-134069980
Ref: Core and Builtins<89>-Footnote-144070046
Ref: Core and Builtins<89>-Footnote-154070112
Ref: Core and Builtins<89>-Footnote-164070178
Ref: Core and Builtins<89>-Footnote-174070244
Ref: Core and Builtins<89>-Footnote-184070310
Ref: Core and Builtins<89>-Footnote-194070376
Ref: Core and Builtins<89>-Footnote-204070442
Ref: Core and Builtins<89>-Footnote-214070508
Ref: Core and Builtins<89>-Footnote-224070574
Node: Library<91>4070640
Ref: whatsnew/changelog id4414070769
Ref: 19ec4070769
Ref: Library<91>-Footnote-14071023
Node: Core and Builtins<90>4071088
Ref: whatsnew/changelog id4424071207
Ref: 19ed4071207
Ref: Core and Builtins<90>-Footnote-14076878
Ref: Core and Builtins<90>-Footnote-24076943
Ref: Core and Builtins<90>-Footnote-34077008
Ref: Core and Builtins<90>-Footnote-44077073
Ref: Core and Builtins<90>-Footnote-54077138
Ref: Core and Builtins<90>-Footnote-64077203
Ref: Core and Builtins<90>-Footnote-74077268
Ref: Core and Builtins<90>-Footnote-84077333
Ref: Core and Builtins<90>-Footnote-94077398
Ref: Core and Builtins<90>-Footnote-104077463
Ref: Core and Builtins<90>-Footnote-114077529
Ref: Core and Builtins<90>-Footnote-124077595
Ref: Core and Builtins<90>-Footnote-134077661
Ref: Core and Builtins<90>-Footnote-144077727
Ref: Core and Builtins<90>-Footnote-154077793
Ref: Core and Builtins<90>-Footnote-164077859
Ref: Core and Builtins<90>-Footnote-174077925
Ref: Core and Builtins<90>-Footnote-184077991
Ref: Core and Builtins<90>-Footnote-194078057
Ref: Core and Builtins<90>-Footnote-204078123
Ref: Core and Builtins<90>-Footnote-214078189
Ref: Core and Builtins<90>-Footnote-224078255
Ref: Core and Builtins<90>-Footnote-234078321
Ref: Core and Builtins<90>-Footnote-244078387
Ref: Core and Builtins<90>-Footnote-254078453
Ref: Core and Builtins<90>-Footnote-264078519
Ref: Core and Builtins<90>-Footnote-274078585
Ref: Core and Builtins<90>-Footnote-284078651
Ref: Core and Builtins<90>-Footnote-294078717
Ref: Core and Builtins<90>-Footnote-304078783
Node: Library<92>4078849
Ref: whatsnew/changelog id4434078974
Ref: 19ee4078974
Ref: Library<92>-Footnote-14118785
Ref: Library<92>-Footnote-24118850
Ref: Library<92>-Footnote-34118915
Ref: Library<92>-Footnote-44118980
Ref: Library<92>-Footnote-54119047
Ref: Library<92>-Footnote-64119112
Ref: Library<92>-Footnote-74119177
Ref: Library<92>-Footnote-84119242
Ref: Library<92>-Footnote-94119307
Ref: Library<92>-Footnote-104119372
Ref: Library<92>-Footnote-114119438
Ref: Library<92>-Footnote-124119504
Ref: Library<92>-Footnote-134119570
Ref: Library<92>-Footnote-144119636
Ref: Library<92>-Footnote-154119702
Ref: Library<92>-Footnote-164119768
Ref: Library<92>-Footnote-174119834
Ref: Library<92>-Footnote-184119900
Ref: Library<92>-Footnote-194119966
Ref: Library<92>-Footnote-204120032
Ref: Library<92>-Footnote-214120098
Ref: Library<92>-Footnote-224120164
Ref: Library<92>-Footnote-234120230
Ref: Library<92>-Footnote-244120296
Ref: Library<92>-Footnote-254120362
Ref: Library<92>-Footnote-264120428
Ref: Library<92>-Footnote-274120494
Ref: Library<92>-Footnote-284120560
Ref: Library<92>-Footnote-294120626
Ref: Library<92>-Footnote-304120692
Ref: Library<92>-Footnote-314120758
Ref: Library<92>-Footnote-324120824
Ref: Library<92>-Footnote-334120890
Ref: Library<92>-Footnote-344120956
Ref: Library<92>-Footnote-354121022
Ref: Library<92>-Footnote-364121065
Ref: Library<92>-Footnote-374121131
Ref: Library<92>-Footnote-384121197
Ref: Library<92>-Footnote-394121263
Ref: Library<92>-Footnote-404121329
Ref: Library<92>-Footnote-414121395
Ref: Library<92>-Footnote-424121461
Ref: Library<92>-Footnote-434121527
Ref: Library<92>-Footnote-444121593
Ref: Library<92>-Footnote-454121659
Ref: Library<92>-Footnote-464121725
Ref: Library<92>-Footnote-474121791
Ref: Library<92>-Footnote-484121857
Ref: Library<92>-Footnote-494121923
Ref: Library<92>-Footnote-504121989
Ref: Library<92>-Footnote-514122055
Ref: Library<92>-Footnote-524122121
Ref: Library<92>-Footnote-534122187
Ref: Library<92>-Footnote-544122253
Ref: Library<92>-Footnote-554122319
Ref: Library<92>-Footnote-564122385
Ref: Library<92>-Footnote-574122451
Ref: Library<92>-Footnote-584122517
Ref: Library<92>-Footnote-594122583
Ref: Library<92>-Footnote-604122649
Ref: Library<92>-Footnote-614122715
Ref: Library<92>-Footnote-624122781
Ref: Library<92>-Footnote-634122847
Ref: Library<92>-Footnote-644122913
Ref: Library<92>-Footnote-654122979
Ref: Library<92>-Footnote-664123045
Ref: Library<92>-Footnote-674123111
Ref: Library<92>-Footnote-684123177
Ref: Library<92>-Footnote-694123243
Ref: Library<92>-Footnote-704123309
Ref: Library<92>-Footnote-714123375
Ref: Library<92>-Footnote-724123441
Ref: Library<92>-Footnote-734123507
Ref: Library<92>-Footnote-744123573
Ref: Library<92>-Footnote-754123639
Ref: Library<92>-Footnote-764123705
Ref: Library<92>-Footnote-774123771
Ref: Library<92>-Footnote-784123837
Ref: Library<92>-Footnote-794123903
Ref: Library<92>-Footnote-804123969
Ref: Library<92>-Footnote-814124035
Ref: Library<92>-Footnote-824124101
Ref: Library<92>-Footnote-834124167
Ref: Library<92>-Footnote-844124233
Ref: Library<92>-Footnote-854124299
Ref: Library<92>-Footnote-864124365
Ref: Library<92>-Footnote-874124431
Ref: Library<92>-Footnote-884124497
Ref: Library<92>-Footnote-894124563
Ref: Library<92>-Footnote-904124629
Ref: Library<92>-Footnote-914124695
Ref: Library<92>-Footnote-924124761
Ref: Library<92>-Footnote-934124827
Ref: Library<92>-Footnote-944124893
Ref: Library<92>-Footnote-954124959
Ref: Library<92>-Footnote-964125025
Ref: Library<92>-Footnote-974125091
Ref: Library<92>-Footnote-984125157
Ref: Library<92>-Footnote-994125223
Ref: Library<92>-Footnote-1004125289
Ref: Library<92>-Footnote-1014125356
Ref: Library<92>-Footnote-1024125423
Ref: Library<92>-Footnote-1034125490
Ref: Library<92>-Footnote-1044125557
Ref: Library<92>-Footnote-1054125624
Ref: Library<92>-Footnote-1064125691
Ref: Library<92>-Footnote-1074125758
Ref: Library<92>-Footnote-1084125825
Ref: Library<92>-Footnote-1094125892
Ref: Library<92>-Footnote-1104125959
Ref: Library<92>-Footnote-1114126026
Ref: Library<92>-Footnote-1124126093
Ref: Library<92>-Footnote-1134126160
Ref: Library<92>-Footnote-1144126227
Ref: Library<92>-Footnote-1154126294
Ref: Library<92>-Footnote-1164126361
Ref: Library<92>-Footnote-1174126428
Ref: Library<92>-Footnote-1184126495
Ref: Library<92>-Footnote-1194126562
Ref: Library<92>-Footnote-1204126629
Ref: Library<92>-Footnote-1214126696
Ref: Library<92>-Footnote-1224126763
Ref: Library<92>-Footnote-1234126830
Ref: Library<92>-Footnote-1244126897
Ref: Library<92>-Footnote-1254126964
Ref: Library<92>-Footnote-1264127031
Ref: Library<92>-Footnote-1274127098
Ref: Library<92>-Footnote-1284127165
Ref: Library<92>-Footnote-1294127232
Ref: Library<92>-Footnote-1304127299
Ref: Library<92>-Footnote-1314127366
Ref: Library<92>-Footnote-1324127433
Ref: Library<92>-Footnote-1334127500
Ref: Library<92>-Footnote-1344127567
Ref: Library<92>-Footnote-1354127634
Ref: Library<92>-Footnote-1364127701
Ref: Library<92>-Footnote-1374127768
Ref: Library<92>-Footnote-1384127835
Ref: Library<92>-Footnote-1394127902
Ref: Library<92>-Footnote-1404127969
Ref: Library<92>-Footnote-1414128036
Ref: Library<92>-Footnote-1424128103
Ref: Library<92>-Footnote-1434128170
Ref: Library<92>-Footnote-1444128237
Ref: Library<92>-Footnote-1454128304
Ref: Library<92>-Footnote-1464128371
Ref: Library<92>-Footnote-1474128438
Ref: Library<92>-Footnote-1484128504
Ref: Library<92>-Footnote-1494128571
Ref: Library<92>-Footnote-1504128638
Ref: Library<92>-Footnote-1514128699
Ref: Library<92>-Footnote-1524128766
Ref: Library<92>-Footnote-1534128833
Ref: Library<92>-Footnote-1544128900
Ref: Library<92>-Footnote-1554128967
Ref: Library<92>-Footnote-1564129034
Ref: Library<92>-Footnote-1574129101
Ref: Library<92>-Footnote-1584129168
Ref: Library<92>-Footnote-1594129235
Ref: Library<92>-Footnote-1604129279
Ref: Library<92>-Footnote-1614129346
Ref: Library<92>-Footnote-1624129413
Ref: Library<92>-Footnote-1634129480
Ref: Library<92>-Footnote-1644129547
Ref: Library<92>-Footnote-1654129614
Ref: Library<92>-Footnote-1664129681
Ref: Library<92>-Footnote-1674129748
Ref: Library<92>-Footnote-1684129815
Ref: Library<92>-Footnote-1694129882
Ref: Library<92>-Footnote-1704129949
Ref: Library<92>-Footnote-1714130016
Ref: Library<92>-Footnote-1724130083
Ref: Library<92>-Footnote-1734130150
Ref: Library<92>-Footnote-1744130217
Ref: Library<92>-Footnote-1754130284
Ref: Library<92>-Footnote-1764130351
Ref: Library<92>-Footnote-1774130418
Ref: Library<92>-Footnote-1784130485
Ref: Library<92>-Footnote-1794130552
Ref: Library<92>-Footnote-1804130619
Ref: Library<92>-Footnote-1814130686
Ref: Library<92>-Footnote-1824130753
Ref: Library<92>-Footnote-1834130820
Ref: Library<92>-Footnote-1844130887
Ref: Library<92>-Footnote-1854130954
Ref: Library<92>-Footnote-1864131021
Ref: Library<92>-Footnote-1874131088
Ref: Library<92>-Footnote-1884131155
Ref: Library<92>-Footnote-1894131222
Ref: Library<92>-Footnote-1904131289
Ref: Library<92>-Footnote-1914131356
Ref: Library<92>-Footnote-1924131423
Ref: Library<92>-Footnote-1934131490
Ref: Library<92>-Footnote-1944131557
Ref: Library<92>-Footnote-1954131624
Ref: Library<92>-Footnote-1964131690
Ref: Library<92>-Footnote-1974131757
Ref: Library<92>-Footnote-1984131824
Ref: Library<92>-Footnote-1994131891
Ref: Library<92>-Footnote-2004131958
Ref: Library<92>-Footnote-2014132025
Ref: Library<92>-Footnote-2024132092
Ref: Library<92>-Footnote-2034132159
Ref: Library<92>-Footnote-2044132226
Ref: Library<92>-Footnote-2054132293
Ref: Library<92>-Footnote-2064132360
Ref: Library<92>-Footnote-2074132427
Ref: Library<92>-Footnote-2084132494
Ref: Library<92>-Footnote-2094132561
Node: Documentation<34>4132628
Ref: whatsnew/changelog id4444132741
Ref: 1a054132741
Ref: Documentation<34>-Footnote-14139085
Ref: Documentation<34>-Footnote-24139150
Ref: Documentation<34>-Footnote-34139215
Ref: Documentation<34>-Footnote-44139280
Ref: Documentation<34>-Footnote-54139345
Ref: Documentation<34>-Footnote-64139410
Ref: Documentation<34>-Footnote-74139462
Ref: Documentation<34>-Footnote-84139527
Ref: Documentation<34>-Footnote-94139592
Ref: Documentation<34>-Footnote-104139651
Ref: Documentation<34>-Footnote-114139717
Ref: Documentation<34>-Footnote-124139783
Ref: Documentation<34>-Footnote-134139849
Ref: Documentation<34>-Footnote-144139915
Ref: Documentation<34>-Footnote-154139981
Ref: Documentation<34>-Footnote-164140047
Ref: Documentation<34>-Footnote-174140113
Ref: Documentation<34>-Footnote-184140179
Ref: Documentation<34>-Footnote-194140245
Ref: Documentation<34>-Footnote-204140311
Ref: Documentation<34>-Footnote-214140377
Ref: Documentation<34>-Footnote-224140443
Ref: Documentation<34>-Footnote-234140509
Ref: Documentation<34>-Footnote-244140575
Ref: Documentation<34>-Footnote-254140641
Ref: Documentation<34>-Footnote-264140707
Ref: Documentation<34>-Footnote-274140773
Ref: Documentation<34>-Footnote-284140839
Ref: Documentation<34>-Footnote-294140905
Ref: Documentation<34>-Footnote-304140971
Ref: Documentation<34>-Footnote-314141037
Ref: Documentation<34>-Footnote-324141103
Ref: Documentation<34>-Footnote-334141169
Ref: Documentation<34>-Footnote-344141235
Ref: Documentation<34>-Footnote-354141301
Ref: Documentation<34>-Footnote-364141367
Ref: Documentation<34>-Footnote-374141433
Ref: Documentation<34>-Footnote-384141499
Ref: Documentation<34>-Footnote-394141565
Ref: Documentation<34>-Footnote-404141631
Ref: Documentation<34>-Footnote-414141697
Ref: Documentation<34>-Footnote-424141763
Node: Tests<37>4141829
Ref: whatsnew/changelog id4454141940
Ref: 1a074141940
Ref: Tests<37>-Footnote-14147802
Ref: Tests<37>-Footnote-24147867
Ref: Tests<37>-Footnote-34147932
Ref: Tests<37>-Footnote-44147997
Ref: Tests<37>-Footnote-54148062
Ref: Tests<37>-Footnote-64148127
Ref: Tests<37>-Footnote-74148192
Ref: Tests<37>-Footnote-84148257
Ref: Tests<37>-Footnote-94148322
Ref: Tests<37>-Footnote-104148387
Ref: Tests<37>-Footnote-114148453
Ref: Tests<37>-Footnote-124148519
Ref: Tests<37>-Footnote-134148585
Ref: Tests<37>-Footnote-144148651
Ref: Tests<37>-Footnote-154148717
Ref: Tests<37>-Footnote-164148783
Ref: Tests<37>-Footnote-174148849
Ref: Tests<37>-Footnote-184148915
Ref: Tests<37>-Footnote-194148981
Ref: Tests<37>-Footnote-204149047
Ref: Tests<37>-Footnote-214149113
Ref: Tests<37>-Footnote-224149179
Ref: Tests<37>-Footnote-234149245
Ref: Tests<37>-Footnote-244149311
Ref: Tests<37>-Footnote-254149377
Ref: Tests<37>-Footnote-264149443
Ref: Tests<37>-Footnote-274149509
Ref: Tests<37>-Footnote-284149575
Ref: Tests<37>-Footnote-294149641
Ref: Tests<37>-Footnote-304149707
Ref: Tests<37>-Footnote-314149773
Ref: Tests<37>-Footnote-324149839
Ref: Tests<37>-Footnote-334149905
Ref: Tests<37>-Footnote-344149971
Ref: Tests<37>-Footnote-354150037
Node: Build<41>4150103
Ref: whatsnew/changelog id4464150208
Ref: 1a0a4150208
Ref: Build<41>-Footnote-14152287
Ref: Build<41>-Footnote-24152352
Ref: Build<41>-Footnote-34152417
Ref: Build<41>-Footnote-44152482
Ref: Build<41>-Footnote-54152547
Ref: Build<41>-Footnote-64152612
Ref: Build<41>-Footnote-74152677
Ref: Build<41>-Footnote-84152742
Ref: Build<41>-Footnote-94152807
Ref: Build<41>-Footnote-104152872
Ref: Build<41>-Footnote-114152938
Node: Windows<35>4153004
Ref: whatsnew/changelog id4474153109
Ref: 1a0b4153109
Ref: Windows<35>-Footnote-14154219
Ref: Windows<35>-Footnote-24154284
Ref: Windows<35>-Footnote-34154349
Ref: Windows<35>-Footnote-44154414
Ref: Windows<35>-Footnote-54154479
Ref: Windows<35>-Footnote-64154544
Ref: Windows<35>-Footnote-74154609
Ref: Windows<35>-Footnote-84154674
Ref: Windows<35>-Footnote-94154739
Node: macOS<27>4154804
Ref: whatsnew/changelog id4484154908
Ref: 1a0d4154908
Ref: macOS<27>-Footnote-14156065
Ref: macOS<27>-Footnote-24156130
Ref: macOS<27>-Footnote-34156195
Ref: macOS<27>-Footnote-44156260
Ref: macOS<27>-Footnote-54156325
Ref: macOS<27>-Footnote-64156390
Ref: macOS<27>-Footnote-74156455
Node: IDLE<23>4156520
Ref: whatsnew/changelog id4494156628
Ref: 1a0e4156628
Ref: IDLE<23>-Footnote-14158148
Ref: IDLE<23>-Footnote-24158213
Ref: IDLE<23>-Footnote-34158278
Ref: IDLE<23>-Footnote-44158343
Ref: IDLE<23>-Footnote-54158408
Ref: IDLE<23>-Footnote-64158473
Ref: IDLE<23>-Footnote-74158538
Ref: IDLE<23>-Footnote-84158603
Ref: IDLE<23>-Footnote-94158668
Node: Tools/Demos<20>4158733
Ref: whatsnew/changelog id4504158841
Ref: 1a0f4158841
Ref: Tools/Demos<20>-Footnote-14159645
Ref: Tools/Demos<20>-Footnote-24159710
Ref: Tools/Demos<20>-Footnote-34159775
Ref: Tools/Demos<20>-Footnote-44159840
Ref: Tools/Demos<20>-Footnote-54159905
Ref: Tools/Demos<20>-Footnote-64159970
Node: C API<36>4160035
Ref: whatsnew/changelog id4514160126
Ref: 1a104160126
Ref: C API<36>-Footnote-14165978
Ref: C API<36>-Footnote-24166043
Ref: C API<36>-Footnote-34166108
Ref: C API<36>-Footnote-44166173
Ref: C API<36>-Footnote-54166238
Ref: C API<36>-Footnote-64166303
Ref: C API<36>-Footnote-74166368
Ref: C API<36>-Footnote-84166433
Ref: C API<36>-Footnote-94166498
Ref: C API<36>-Footnote-104166563
Ref: C API<36>-Footnote-114166629
Ref: C API<36>-Footnote-124166695
Ref: C API<36>-Footnote-134166761
Ref: C API<36>-Footnote-144166827
Ref: C API<36>-Footnote-154166893
Ref: C API<36>-Footnote-164166959
Ref: C API<36>-Footnote-174167025
Ref: C API<36>-Footnote-184167091
Ref: C API<36>-Footnote-194167157
Ref: C API<36>-Footnote-204167223
Ref: C API<36>-Footnote-214167266
Ref: C API<36>-Footnote-224167332
Ref: C API<36>-Footnote-234167398
Ref: C API<36>-Footnote-244167464
Ref: C API<36>-Footnote-254167507
Ref: C API<36>-Footnote-264167550
Node: Python 3 10 0 beta 14167616
Ref: whatsnew/changelog python-3-10-0-beta-14167742
Ref: 1a134167742
Node: Security<27>4168227
Ref: whatsnew/changelog id4524168326
Ref: 1a144168326
Ref: Security<27>-Footnote-14171252
Ref: Security<27>-Footnote-24171317
Ref: Security<27>-Footnote-34171382
Ref: Security<27>-Footnote-44171447
Ref: Security<27>-Footnote-54171512
Ref: Security<27>-Footnote-64171577
Ref: Security<27>-Footnote-74171642
Ref: Security<27>-Footnote-84171707
Ref: Security<27>-Footnote-94171772
Ref: Security<27>-Footnote-104171837
Ref: Security<27>-Footnote-114171903
Node: Core and Builtins<91>4171969
Ref: whatsnew/changelog id4534172088
Ref: 1a174172088
Ref: Core and Builtins<91>-Footnote-14173446
Ref: Core and Builtins<91>-Footnote-24173511
Ref: Core and Builtins<91>-Footnote-34173576
Ref: Core and Builtins<91>-Footnote-44173641
Ref: Core and Builtins<91>-Footnote-54173706
Ref: Core and Builtins<91>-Footnote-64173771
Ref: Core and Builtins<91>-Footnote-74173836
Node: Library<93>4173901
Ref: whatsnew/changelog id4544174029
Ref: 1a194174029
Ref: Library<93>-Footnote-14174294
Ref: Library<93>-Footnote-24174359
Node: Core and Builtins<92>4174424
Ref: whatsnew/changelog id4554174542
Ref: 1a1a4174542
Ref: Core and Builtins<92>-Footnote-14178560
Ref: Core and Builtins<92>-Footnote-24178625
Ref: Core and Builtins<92>-Footnote-34178690
Ref: Core and Builtins<92>-Footnote-44178755
Ref: Core and Builtins<92>-Footnote-54178820
Ref: Core and Builtins<92>-Footnote-64178862
Ref: Core and Builtins<92>-Footnote-74178927
Ref: Core and Builtins<92>-Footnote-84178992
Ref: Core and Builtins<92>-Footnote-94179057
Ref: Core and Builtins<92>-Footnote-104179122
Ref: Core and Builtins<92>-Footnote-114179188
Ref: Core and Builtins<92>-Footnote-124179254
Ref: Core and Builtins<92>-Footnote-134179320
Ref: Core and Builtins<92>-Footnote-144179386
Ref: Core and Builtins<92>-Footnote-154179452
Ref: Core and Builtins<92>-Footnote-164179518
Ref: Core and Builtins<92>-Footnote-174179584
Ref: Core and Builtins<92>-Footnote-184179650
Ref: Core and Builtins<92>-Footnote-194179716
Ref: Core and Builtins<92>-Footnote-204179782
Ref: Core and Builtins<92>-Footnote-214179848
Ref: Core and Builtins<92>-Footnote-224179914
Node: Library<94>4179980
Ref: whatsnew/changelog id4564180108
Ref: 1a1d4180108
Ref: Library<94>-Footnote-14180299
Node: Core and Builtins<93>4180364
Ref: whatsnew/changelog id4574180482
Ref: 1a1e4180482
Ref: Core and Builtins<93>-Footnote-14181134
Ref: Core and Builtins<93>-Footnote-24181199
Ref: Core and Builtins<93>-Footnote-34181264
Node: Library<95>4181329
Ref: whatsnew/changelog id4584181453
Ref: 1a1f4181453
Ref: Library<95>-Footnote-14198234
Ref: Library<95>-Footnote-24198299
Ref: Library<95>-Footnote-34198364
Ref: Library<95>-Footnote-44198429
Ref: Library<95>-Footnote-54198494
Ref: Library<95>-Footnote-64198559
Ref: Library<95>-Footnote-74198624
Ref: Library<95>-Footnote-84198689
Ref: Library<95>-Footnote-94198754
Ref: Library<95>-Footnote-104198819
Ref: Library<95>-Footnote-114198885
Ref: Library<95>-Footnote-124198951
Ref: Library<95>-Footnote-134199017
Ref: Library<95>-Footnote-144199083
Ref: Library<95>-Footnote-154199149
Ref: Library<95>-Footnote-164199215
Ref: Library<95>-Footnote-174199281
Ref: Library<95>-Footnote-184199347
Ref: Library<95>-Footnote-194199413
Ref: Library<95>-Footnote-204199479
Ref: Library<95>-Footnote-214199545
Ref: Library<95>-Footnote-224199611
Ref: Library<95>-Footnote-234199654
Ref: Library<95>-Footnote-244199720
Ref: Library<95>-Footnote-254199786
Ref: Library<95>-Footnote-264199852
Ref: Library<95>-Footnote-274199918
Ref: Library<95>-Footnote-284199984
Ref: Library<95>-Footnote-294200050
Ref: Library<95>-Footnote-304200116
Ref: Library<95>-Footnote-314200182
Ref: Library<95>-Footnote-324200248
Ref: Library<95>-Footnote-334200314
Ref: Library<95>-Footnote-344200380
Ref: Library<95>-Footnote-354200446
Ref: Library<95>-Footnote-364200512
Ref: Library<95>-Footnote-374200578
Ref: Library<95>-Footnote-384200644
Ref: Library<95>-Footnote-394200710
Ref: Library<95>-Footnote-404200776
Ref: Library<95>-Footnote-414200842
Ref: Library<95>-Footnote-424200908
Ref: Library<95>-Footnote-434200951
Ref: Library<95>-Footnote-444201017
Ref: Library<95>-Footnote-454201083
Ref: Library<95>-Footnote-464201139
Ref: Library<95>-Footnote-474201205
Ref: Library<95>-Footnote-484201271
Ref: Library<95>-Footnote-494201337
Ref: Library<95>-Footnote-504201403
Ref: Library<95>-Footnote-514201469
Ref: Library<95>-Footnote-524201535
Ref: Library<95>-Footnote-534201601
Ref: Library<95>-Footnote-544201666
Ref: Library<95>-Footnote-554201732
Ref: Library<95>-Footnote-564201798
Ref: Library<95>-Footnote-574201864
Ref: Library<95>-Footnote-584201929
Ref: Library<95>-Footnote-594201995
Ref: Library<95>-Footnote-604202061
Ref: Library<95>-Footnote-614202127
Ref: Library<95>-Footnote-624202193
Ref: Library<95>-Footnote-634202259
Ref: Library<95>-Footnote-644202325
Ref: Library<95>-Footnote-654202391
Ref: Library<95>-Footnote-664202457
Ref: Library<95>-Footnote-674202523
Ref: Library<95>-Footnote-684202589
Ref: Library<95>-Footnote-694202632
Ref: Library<95>-Footnote-704202698
Ref: Library<95>-Footnote-714202764
Ref: Library<95>-Footnote-724202830
Ref: Library<95>-Footnote-734202896
Ref: Library<95>-Footnote-744202962
Ref: Library<95>-Footnote-754203028
Ref: Library<95>-Footnote-764203094
Ref: Library<95>-Footnote-774203160
Ref: Library<95>-Footnote-784203226
Ref: Library<95>-Footnote-794203292
Ref: Library<95>-Footnote-804203358
Ref: Library<95>-Footnote-814203424
Ref: Library<95>-Footnote-824203490
Ref: Library<95>-Footnote-834203556
Node: Documentation<35>4203622
Ref: whatsnew/changelog id4594203734
Ref: 1a254203734
Ref: Documentation<35>-Footnote-14204748
Ref: Documentation<35>-Footnote-24204813
Ref: Documentation<35>-Footnote-34204878
Ref: Documentation<35>-Footnote-44204943
Ref: Documentation<35>-Footnote-54205008
Ref: Documentation<35>-Footnote-64205073
Ref: Documentation<35>-Footnote-74205138
Node: Tests<38>4205203
Ref: whatsnew/changelog id4604205313
Ref: 1a264205313
Ref: Tests<38>-Footnote-14206392
Ref: Tests<38>-Footnote-24206457
Ref: Tests<38>-Footnote-34206522
Ref: Tests<38>-Footnote-44206587
Ref: Tests<38>-Footnote-54206652
Node: Build<42>4206717
Ref: whatsnew/changelog id4614206821
Ref: 1a274206821
Ref: Build<42>-Footnote-14207083
Ref: Build<42>-Footnote-24207148
Ref: Build<42>-Footnote-34207213
Node: Windows<36>4207255
Ref: whatsnew/changelog id4624207359
Ref: 1a284207359
Ref: Windows<36>-Footnote-14208704
Ref: Windows<36>-Footnote-24208769
Ref: Windows<36>-Footnote-34208834
Ref: Windows<36>-Footnote-44208899
Ref: Windows<36>-Footnote-54208964
Ref: Windows<36>-Footnote-64209029
Ref: Windows<36>-Footnote-74209094
Ref: Windows<36>-Footnote-84209159
Ref: Windows<36>-Footnote-94209224
Node: macOS<28>4209289
Ref: whatsnew/changelog id4634209392
Ref: 1a2c4209392
Ref: macOS<28>-Footnote-14210702
Ref: macOS<28>-Footnote-24210767
Ref: macOS<28>-Footnote-34210832
Ref: macOS<28>-Footnote-44210897
Ref: macOS<28>-Footnote-54210962
Ref: macOS<28>-Footnote-64211027
Node: IDLE<24>4211092
Ref: whatsnew/changelog id4644211193
Ref: 1a2d4211193
Ref: IDLE<24>-Footnote-14211995
Ref: IDLE<24>-Footnote-24212060
Ref: IDLE<24>-Footnote-34212125
Ref: IDLE<24>-Footnote-44212190
Ref: IDLE<24>-Footnote-54212255
Node: C API<37>4212320
Ref: whatsnew/changelog id4654212403
Ref: 1a2e4212403
Ref: C API<37>-Footnote-14214651
Ref: C API<37>-Footnote-24214716
Ref: C API<37>-Footnote-34214781
Ref: C API<37>-Footnote-44214846
Ref: C API<37>-Footnote-54214911
Ref: C API<37>-Footnote-64214976
Ref: C API<37>-Footnote-74215041
Ref: C API<37>-Footnote-84215106
Ref: C API<37>-Footnote-94215171
Ref: C API<37>-Footnote-104215213
Node: Python 3 10 0 alpha 74215279
Ref: whatsnew/changelog python-3-10-0-alpha-74215405
Ref: 1a2f4215405
Node: Security<28>4215804
Ref: whatsnew/changelog id4664215904
Ref: 1a304215904
Ref: Security<28>-Footnote-14216988
Ref: Security<28>-Footnote-24217053
Ref: Security<28>-Footnote-34217108
Ref: Security<28>-Footnote-44217173
Node: Core and Builtins<94>4217238
Ref: whatsnew/changelog id4674217358
Ref: 1a314217358
Ref: Core and Builtins<94>-Footnote-14217978
Ref: Core and Builtins<94>-Footnote-24218043
Ref: Core and Builtins<94>-Footnote-34218108
Ref: Core and Builtins<94>-Footnote-44218173
Node: Library<96>4218238
Ref: whatsnew/changelog id4684218367
Ref: 1a324218367
Ref: Library<96>-Footnote-14218545
Node: Core and Builtins<95>4218610
Ref: whatsnew/changelog id4694218729
Ref: 1a334218729
Ref: Core and Builtins<95>-Footnote-14222618
Ref: Core and Builtins<95>-Footnote-24222683
Ref: Core and Builtins<95>-Footnote-34222748
Ref: Core and Builtins<95>-Footnote-44222813
Ref: Core and Builtins<95>-Footnote-54222855
Ref: Core and Builtins<95>-Footnote-64222920
Ref: Core and Builtins<95>-Footnote-74222985
Ref: Core and Builtins<95>-Footnote-84223050
Ref: Core and Builtins<95>-Footnote-94223115
Ref: Core and Builtins<95>-Footnote-104223180
Ref: Core and Builtins<95>-Footnote-114223246
Ref: Core and Builtins<95>-Footnote-124223312
Ref: Core and Builtins<95>-Footnote-134223378
Ref: Core and Builtins<95>-Footnote-144223444
Ref: Core and Builtins<95>-Footnote-154223510
Ref: Core and Builtins<95>-Footnote-164223576
Ref: Core and Builtins<95>-Footnote-174223642
Ref: Core and Builtins<95>-Footnote-184223685
Ref: Core and Builtins<95>-Footnote-194223751
Node: Library<97>4223817
Ref: whatsnew/changelog id4704223942
Ref: 1a344223942
Ref: Library<97>-Footnote-14231625
Ref: Library<97>-Footnote-24231690
Ref: Library<97>-Footnote-34231755
Ref: Library<97>-Footnote-44231820
Ref: Library<97>-Footnote-54231885
Ref: Library<97>-Footnote-64231950
Ref: Library<97>-Footnote-74232015
Ref: Library<97>-Footnote-84232080
Ref: Library<97>-Footnote-94232145
Ref: Library<97>-Footnote-104232210
Ref: Library<97>-Footnote-114232276
Ref: Library<97>-Footnote-124232342
Ref: Library<97>-Footnote-134232408
Ref: Library<97>-Footnote-144232474
Ref: Library<97>-Footnote-154232540
Ref: Library<97>-Footnote-164232583
Ref: Library<97>-Footnote-174232649
Ref: Library<97>-Footnote-184232715
Ref: Library<97>-Footnote-194232781
Ref: Library<97>-Footnote-204232847
Ref: Library<97>-Footnote-214232913
Ref: Library<97>-Footnote-224232979
Ref: Library<97>-Footnote-234233045
Ref: Library<97>-Footnote-244233111
Ref: Library<97>-Footnote-254233177
Ref: Library<97>-Footnote-264233259
Ref: Library<97>-Footnote-274233325
Ref: Library<97>-Footnote-284233391
Ref: Library<97>-Footnote-294233457
Ref: Library<97>-Footnote-304233523
Ref: Library<97>-Footnote-314233589
Ref: Library<97>-Footnote-324233655
Ref: Library<97>-Footnote-334233721
Ref: Library<97>-Footnote-344233787
Ref: Library<97>-Footnote-354233853
Ref: Library<97>-Footnote-364233919
Ref: Library<97>-Footnote-374233985
Ref: Library<97>-Footnote-384234051
Ref: Library<97>-Footnote-394234117
Ref: Library<97>-Footnote-404234183
Ref: Library<97>-Footnote-414234249
Ref: Library<97>-Footnote-424234315
Ref: Library<97>-Footnote-434234381
Ref: Library<97>-Footnote-444234447
Ref: Library<97>-Footnote-454234513
Node: Documentation<36>4234579
Ref: whatsnew/changelog id4714234692
Ref: 1a3c4234692
Ref: Documentation<36>-Footnote-14235389
Ref: Documentation<36>-Footnote-24235454
Ref: Documentation<36>-Footnote-34235519
Ref: Documentation<36>-Footnote-44235584
Node: Tests<39>4235649
Ref: whatsnew/changelog id4724235760
Ref: 1a3d4235760
Ref: Tests<39>-Footnote-14236065
Ref: Tests<39>-Footnote-24236130
Node: Build<43>4236195
Ref: whatsnew/changelog id4734236300
Ref: 1a3e4236300
Ref: Build<43>-Footnote-14237271
Ref: Build<43>-Footnote-24237336
Ref: Build<43>-Footnote-34237401
Ref: Build<43>-Footnote-44237466
Ref: Build<43>-Footnote-54237531
Ref: Build<43>-Footnote-64237596
Node: Windows<37>4237661
Ref: whatsnew/changelog id4744237765
Ref: 1a3f4237765
Ref: Windows<37>-Footnote-14237955
Node: IDLE<25>4238020
Ref: whatsnew/changelog id4754238124
Ref: 1a404238124
Ref: IDLE<25>-Footnote-14238367
Node: C API<38>4238432
Ref: whatsnew/changelog id4764238516
Ref: 1a414238516
Ref: C API<38>-Footnote-14241982
Ref: C API<38>-Footnote-24242047
Ref: C API<38>-Footnote-34242112
Ref: C API<38>-Footnote-44242177
Ref: C API<38>-Footnote-54242242
Ref: C API<38>-Footnote-64242307
Ref: C API<38>-Footnote-74242372
Ref: C API<38>-Footnote-84242437
Ref: C API<38>-Footnote-94242502
Node: Python 3 10 0 alpha 64242544
Ref: whatsnew/changelog python-3-10-0-alpha-64242671
Ref: 1a424242671
Node: Security<29>4243159
Ref: whatsnew/changelog id4774243259
Ref: 1a434243259
Ref: Security<29>-Footnote-14243505
Node: Core and Builtins<96>4243570
Ref: whatsnew/changelog id4784243690
Ref: 1a444243690
Ref: Core and Builtins<96>-Footnote-14245335
Ref: Core and Builtins<96>-Footnote-24245400
Ref: Core and Builtins<96>-Footnote-34245465
Ref: Core and Builtins<96>-Footnote-44245507
Ref: Core and Builtins<96>-Footnote-54245572
Ref: Core and Builtins<96>-Footnote-64245637
Ref: Core and Builtins<96>-Footnote-74245702
Ref: Core and Builtins<96>-Footnote-84245767
Node: Library<98>4245832
Ref: whatsnew/changelog id4794245961
Ref: 1a454245961
Ref: Library<98>-Footnote-14246661
Node: Core and Builtins<97>4246726
Ref: whatsnew/changelog id4804246845
Ref: 1a464246845
Ref: Core and Builtins<97>-Footnote-14247539
Ref: Core and Builtins<97>-Footnote-24247604
Ref: Core and Builtins<97>-Footnote-34247669
Ref: Core and Builtins<97>-Footnote-44247734
Ref: Core and Builtins<97>-Footnote-54247799
Node: Library<99>4247841
Ref: whatsnew/changelog id4814247970
Ref: 1a474247970
Ref: Library<99>-Footnote-14248380
Node: Core and Builtins<98>4248445
Ref: whatsnew/changelog id4824248565
Ref: 1a484248565
Ref: Core and Builtins<98>-Footnote-14248878
Node: Library<100>4248943
Ref: whatsnew/changelog id4834249069
Ref: 1a494249069
Ref: Library<100>-Footnote-14251904
Ref: Library<100>-Footnote-24251969
Ref: Library<100>-Footnote-34252034
Ref: Library<100>-Footnote-44252099
Ref: Library<100>-Footnote-54252164
Ref: Library<100>-Footnote-64252229
Ref: Library<100>-Footnote-74252294
Ref: Library<100>-Footnote-84252359
Ref: Library<100>-Footnote-94252424
Ref: Library<100>-Footnote-104252489
Ref: Library<100>-Footnote-114252555
Ref: Library<100>-Footnote-124252621
Ref: Library<100>-Footnote-134252687
Ref: Library<100>-Footnote-144252753
Ref: Library<100>-Footnote-154252819
Ref: Library<100>-Footnote-164252885
Node: Documentation<37>4252951
Ref: whatsnew/changelog id4844253065
Ref: 1a4d4253065
Ref: Documentation<37>-Footnote-14253419
Ref: Documentation<37>-Footnote-24253484
Ref: Documentation<37>-Footnote-34253549
Node: Tests<40>4253591
Ref: whatsnew/changelog id4854253702
Ref: 1a4e4253702
Ref: Tests<40>-Footnote-14253893
Node: Build<44>4253958
Ref: whatsnew/changelog id4864254063
Ref: 1a4f4254063
Ref: Build<44>-Footnote-14255134
Ref: Build<44>-Footnote-24255199
Ref: Build<44>-Footnote-34255264
Ref: Build<44>-Footnote-44255329
Ref: Build<44>-Footnote-54255394
Node: Windows<38>4255459
Ref: whatsnew/changelog id4874255564
Ref: 1a504255564
Ref: Windows<38>-Footnote-14255730
Node: macOS<29>4255795
Ref: whatsnew/changelog id4884255899
Ref: 1a524255899
Ref: macOS<29>-Footnote-14256042
Node: IDLE<26>4256107
Ref: whatsnew/changelog id4894256209
Ref: 1a534256209
Ref: IDLE<26>-Footnote-14256481
Node: C API<39>4256546
Ref: whatsnew/changelog id4904256630
Ref: 1a544256630
Ref: C API<39>-Footnote-14258384
Ref: C API<39>-Footnote-24258449
Ref: C API<39>-Footnote-34258514
Ref: C API<39>-Footnote-44258579
Ref: C API<39>-Footnote-54258644
Ref: C API<39>-Footnote-64258709
Ref: C API<39>-Footnote-74258774
Ref: C API<39>-Footnote-84258839
Ref: C API<39>-Footnote-94258904
Node: Python 3 10 0 alpha 54258969
Ref: whatsnew/changelog python-3-10-0-alpha-54259096
Ref: 1a5c4259096
Node: Security<30>4259518
Ref: whatsnew/changelog id4914259618
Ref: 1a5d4259618
Ref: Security<30>-Footnote-14259840
Node: Core and Builtins<99>4259905
Ref: whatsnew/changelog id4924260026
Ref: 1a604260026
Ref: Core and Builtins<99>-Footnote-14262157
Ref: Core and Builtins<99>-Footnote-24262222
Ref: Core and Builtins<99>-Footnote-34262287
Ref: Core and Builtins<99>-Footnote-44262352
Ref: Core and Builtins<99>-Footnote-54262417
Ref: Core and Builtins<99>-Footnote-64262482
Ref: Core and Builtins<99>-Footnote-74262547
Ref: Core and Builtins<99>-Footnote-84262612
Ref: Core and Builtins<99>-Footnote-94262677
Ref: Core and Builtins<99>-Footnote-104262742
Ref: Core and Builtins<99>-Footnote-114262808
Ref: Core and Builtins<99>-Footnote-124262874
Node: Library<101>4262940
Ref: whatsnew/changelog id4934263071
Ref: 1a614263071
Ref: Library<101>-Footnote-14263284
Node: Core and Builtins<100>4263349
Ref: whatsnew/changelog id4944263471
Ref: 1a624263471
Ref: Core and Builtins<100>-Footnote-14263810
Ref: Core and Builtins<100>-Footnote-24263875
Node: Library<102>4263940
Ref: whatsnew/changelog id4954264067
Ref: 1a634264067
Ref: Library<102>-Footnote-14269011
Ref: Library<102>-Footnote-24269076
Ref: Library<102>-Footnote-34269141
Ref: Library<102>-Footnote-44269206
Ref: Library<102>-Footnote-54269271
Ref: Library<102>-Footnote-64269336
Ref: Library<102>-Footnote-74269401
Ref: Library<102>-Footnote-84269466
Ref: Library<102>-Footnote-94269531
Ref: Library<102>-Footnote-104269596
Ref: Library<102>-Footnote-114269662
Ref: Library<102>-Footnote-124269728
Ref: Library<102>-Footnote-134269794
Ref: Library<102>-Footnote-144269860
Ref: Library<102>-Footnote-154269926
Ref: Library<102>-Footnote-164269992
Ref: Library<102>-Footnote-174270058
Ref: Library<102>-Footnote-184270124
Ref: Library<102>-Footnote-194270167
Ref: Library<102>-Footnote-204270233
Ref: Library<102>-Footnote-214270299
Ref: Library<102>-Footnote-224270365
Ref: Library<102>-Footnote-234270431
Ref: Library<102>-Footnote-244270499
Ref: Library<102>-Footnote-254270542
Ref: Library<102>-Footnote-264270608
Ref: Library<102>-Footnote-274270674
Ref: Library<102>-Footnote-284270740
Ref: Library<102>-Footnote-294270806
Ref: Library<102>-Footnote-304270872
Ref: Library<102>-Footnote-314270938
Ref: Library<102>-Footnote-324271004
Ref: Library<102>-Footnote-334271070
Ref: Library<102>-Footnote-344271136
Node: Documentation<38>4271202
Ref: whatsnew/changelog id4964271316
Ref: 1a644271316
Ref: Documentation<38>-Footnote-14271644
Ref: Documentation<38>-Footnote-24271709
Node: Tests<41>4271774
Ref: whatsnew/changelog id4974271885
Ref: 1a654271885
Ref: Tests<41>-Footnote-14272241
Ref: Tests<41>-Footnote-24272306
Node: Build<45>4272371
Ref: whatsnew/changelog id4984272476
Ref: 1a664272476
Ref: Build<45>-Footnote-14273671
Ref: Build<45>-Footnote-24273736
Ref: Build<45>-Footnote-34273801
Ref: Build<45>-Footnote-44273866
Ref: Build<45>-Footnote-54273931
Node: Windows<39>4273996
Ref: whatsnew/changelog id4994274101
Ref: 1a674274101
Ref: Windows<39>-Footnote-14274314
Ref: Windows<39>-Footnote-24274379
Node: macOS<30>4274444
Ref: whatsnew/changelog id5004274548
Ref: 1a684274548
Ref: macOS<30>-Footnote-14274801
Node: IDLE<27>4274866
Ref: whatsnew/changelog id5014274968
Ref: 1a694274968
Ref: IDLE<27>-Footnote-14275532
Ref: IDLE<27>-Footnote-24275597
Ref: IDLE<27>-Footnote-34275662
Ref: IDLE<27>-Footnote-44275727
Node: C API<40>4275792
Ref: whatsnew/changelog id5024275876
Ref: 1a6a4275876
Ref: C API<40>-Footnote-14276482
Ref: C API<40>-Footnote-24276547
Node: Python 3 10 0 alpha 44276612
Ref: whatsnew/changelog python-3-10-0-alpha-44276739
Ref: 1a6c4276739
Node: Core and Builtins<101>4277196
Ref: whatsnew/changelog id5034277297
Ref: 1a6d4277297
Ref: Core and Builtins<101>-Footnote-14278769
Ref: Core and Builtins<101>-Footnote-24278834
Ref: Core and Builtins<101>-Footnote-34278899
Ref: Core and Builtins<101>-Footnote-44278964
Ref: Core and Builtins<101>-Footnote-54279029
Ref: Core and Builtins<101>-Footnote-64279094
Ref: Core and Builtins<101>-Footnote-74279159
Ref: Core and Builtins<101>-Footnote-84279224
Ref: Core and Builtins<101>-Footnote-94279289
Ref: Core and Builtins<101>-Footnote-104279354
Node: Library<103>4279420
Ref: whatsnew/changelog id5044279552
Ref: 1a6e4279552
Ref: Library<103>-Footnote-14279817
Node: Core and Builtins<102>4279882
Ref: whatsnew/changelog id5054280004
Ref: 1a6f4280004
Ref: Core and Builtins<102>-Footnote-14280281
Node: Library<104>4280346
Ref: whatsnew/changelog id5064280478
Ref: 1a714280478
Ref: Library<104>-Footnote-14281732
Ref: Library<104>-Footnote-24281797
Ref: Library<104>-Footnote-34281839
Ref: Library<104>-Footnote-44281904
Ref: Library<104>-Footnote-54281969
Ref: Library<104>-Footnote-64282034
Ref: Library<104>-Footnote-74282101
Node: Core and Builtins<103>4282143
Ref: whatsnew/changelog id5074282265
Ref: 1a724282265
Ref: Core and Builtins<103>-Footnote-14282720
Ref: Core and Builtins<103>-Footnote-24282785
Node: Library<105>4282850
Ref: whatsnew/changelog id5084282977
Ref: 1a734282977
Ref: Library<105>-Footnote-14291798
Ref: Library<105>-Footnote-24291863
Ref: Library<105>-Footnote-34291928
Ref: Library<105>-Footnote-44291993
Ref: Library<105>-Footnote-54292058
Ref: Library<105>-Footnote-64292123
Ref: Library<105>-Footnote-74292188
Ref: Library<105>-Footnote-84292230
Ref: Library<105>-Footnote-94292272
Ref: Library<105>-Footnote-104292337
Ref: Library<105>-Footnote-114292403
Ref: Library<105>-Footnote-124292469
Ref: Library<105>-Footnote-134292535
Ref: Library<105>-Footnote-144292601
Ref: Library<105>-Footnote-154292667
Ref: Library<105>-Footnote-164292733
Ref: Library<105>-Footnote-174292799
Ref: Library<105>-Footnote-184292865
Ref: Library<105>-Footnote-194292930
Ref: Library<105>-Footnote-204292998
Ref: Library<105>-Footnote-214293041
Ref: Library<105>-Footnote-224293107
Ref: Library<105>-Footnote-234293173
Ref: Library<105>-Footnote-244293239
Ref: Library<105>-Footnote-254293305
Ref: Library<105>-Footnote-264293371
Ref: Library<105>-Footnote-274293437
Ref: Library<105>-Footnote-284293503
Ref: Library<105>-Footnote-294293569
Ref: Library<105>-Footnote-304293635
Ref: Library<105>-Footnote-314293701
Ref: Library<105>-Footnote-324293767
Ref: Library<105>-Footnote-334293810
Ref: Library<105>-Footnote-344293876
Ref: Library<105>-Footnote-354293942
Ref: Library<105>-Footnote-364294008
Ref: Library<105>-Footnote-374294074
Ref: Library<105>-Footnote-384294140
Ref: Library<105>-Footnote-394294206
Ref: Library<105>-Footnote-404294272
Ref: Library<105>-Footnote-414294338
Ref: Library<105>-Footnote-424294404
Ref: Library<105>-Footnote-434294470
Ref: Library<105>-Footnote-444294536
Ref: Library<105>-Footnote-454294602
Ref: Library<105>-Footnote-464294668
Ref: Library<105>-Footnote-474294734
Ref: Library<105>-Footnote-484294802
Ref: Library<105>-Footnote-494294845
Ref: Library<105>-Footnote-504294911
Ref: Library<105>-Footnote-514294977
Ref: Library<105>-Footnote-524295043
Ref: Library<105>-Footnote-534295109
Ref: Library<105>-Footnote-544295175
Ref: Library<105>-Footnote-554295241
Ref: Library<105>-Footnote-564295307
Ref: Library<105>-Footnote-574295373
Ref: Library<105>-Footnote-584295439
Node: Documentation<39>4295505
Ref: whatsnew/changelog id5094295619
Ref: 1a794295619
Ref: Documentation<39>-Footnote-14295935
Ref: Documentation<39>-Footnote-24296000
Node: Tests<42>4296065
Ref: whatsnew/changelog id5104296176
Ref: 1a7b4296176
Ref: Tests<42>-Footnote-14296953
Ref: Tests<42>-Footnote-24297018
Ref: Tests<42>-Footnote-34297083
Ref: Tests<42>-Footnote-44297148
Ref: Tests<42>-Footnote-54297213
Ref: Tests<42>-Footnote-64297278
Ref: Tests<42>-Footnote-74297343
Ref: Tests<42>-Footnote-84297408
Node: Build<46>4297473
Ref: whatsnew/changelog id5114297576
Ref: 1a7c4297576
Ref: Build<46>-Footnote-14298567
Ref: Build<46>-Footnote-24298632
Ref: Build<46>-Footnote-34298697
Ref: Build<46>-Footnote-44298762
Ref: Build<46>-Footnote-54298827
Ref: Build<46>-Footnote-64298892
Node: macOS<31>4298957
Ref: whatsnew/changelog id5124299066
Ref: 1a7d4299066
Ref: macOS<31>-Footnote-14299386
Ref: macOS<31>-Footnote-24299451
Ref: macOS<31>-Footnote-34299516
Node: Tools/Demos<21>4299581
Ref: whatsnew/changelog id5134299690
Ref: 1a7e4299690
Ref: Tools/Demos<21>-Footnote-14300016
Ref: Tools/Demos<21>-Footnote-24300081
Node: C API<41>4300146
Ref: whatsnew/changelog id5144300237
Ref: 1a7f4300237
Ref: C API<41>-Footnote-14301080
Ref: C API<41>-Footnote-24301145
Ref: C API<41>-Footnote-34301210
Ref: C API<41>-Footnote-44301277
Ref: C API<41>-Footnote-54301342
Node: Python 3 10 0 alpha 34301407
Ref: whatsnew/changelog python-3-10-0-alpha-34301534
Ref: 1a804301534
Node: Security<31>4302129
Ref: whatsnew/changelog id5154302230
Ref: 1a814302230
Ref: Security<31>-Footnote-14302470
Node: Core and Builtins<104>4302535
Ref: whatsnew/changelog id5164302657
Ref: 1a824302657
Ref: Core and Builtins<104>-Footnote-14304276
Ref: Core and Builtins<104>-Footnote-24304341
Ref: Core and Builtins<104>-Footnote-34304406
Ref: Core and Builtins<104>-Footnote-44304471
Ref: Core and Builtins<104>-Footnote-54304536
Node: Library<106>4304601
Ref: whatsnew/changelog id5174304733
Ref: 1a854304733
Ref: Library<106>-Footnote-14304959
Ref: Library<106>-Footnote-24305026
Node: Core and Builtins<105>4305068
Ref: whatsnew/changelog id5184305190
Ref: 1a864305190
Ref: Core and Builtins<105>-Footnote-14307033
Ref: Core and Builtins<105>-Footnote-24307098
Ref: Core and Builtins<105>-Footnote-34307163
Ref: Core and Builtins<105>-Footnote-44307228
Ref: Core and Builtins<105>-Footnote-54307293
Ref: Core and Builtins<105>-Footnote-64307358
Ref: Core and Builtins<105>-Footnote-74307423
Ref: Core and Builtins<105>-Footnote-84307488
Ref: Core and Builtins<105>-Footnote-94307553
Ref: Core and Builtins<105>-Footnote-104307618
Node: Library<107>4307684
Ref: whatsnew/changelog id5194307816
Ref: 1a874307816
Ref: Library<107>-Footnote-14307953
Node: Core and Builtins<106>4308018
Ref: whatsnew/changelog id5204308140
Ref: 1a884308140
Ref: Core and Builtins<106>-Footnote-14308366
Node: Library<108>4308431
Ref: whatsnew/changelog id5214308563
Ref: 1a894308563
Ref: Library<108>-Footnote-14308699
Node: Core and Builtins<107>4308764
Ref: whatsnew/changelog id5224308886
Ref: 1a8a4308886
Ref: Core and Builtins<107>-Footnote-14309471
Ref: Core and Builtins<107>-Footnote-24309536
Ref: Core and Builtins<107>-Footnote-34309601
Node: Library<109>4309666
Ref: whatsnew/changelog id5234309793
Ref: 1a8b4309793
Ref: Library<109>-Footnote-14320865
Ref: Library<109>-Footnote-24320929
Ref: Library<109>-Footnote-34320994
Ref: Library<109>-Footnote-44321059
Ref: Library<109>-Footnote-54321124
Ref: Library<109>-Footnote-64321189
Ref: Library<109>-Footnote-74321254
Ref: Library<109>-Footnote-84321319
Ref: Library<109>-Footnote-94321384
Ref: Library<109>-Footnote-104321449
Ref: Library<109>-Footnote-114321515
Ref: Library<109>-Footnote-124321581
Ref: Library<109>-Footnote-134321647
Ref: Library<109>-Footnote-144321713
Ref: Library<109>-Footnote-154321779
Ref: Library<109>-Footnote-164321845
Ref: Library<109>-Footnote-174321911
Ref: Library<109>-Footnote-184321977
Ref: Library<109>-Footnote-194322043
Ref: Library<109>-Footnote-204322109
Ref: Library<109>-Footnote-214322175
Ref: Library<109>-Footnote-224322241
Ref: Library<109>-Footnote-234322307
Ref: Library<109>-Footnote-244322375
Ref: Library<109>-Footnote-254322441
Ref: Library<109>-Footnote-264322507
Ref: Library<109>-Footnote-274322550
Ref: Library<109>-Footnote-284322616
Ref: Library<109>-Footnote-294322682
Ref: Library<109>-Footnote-304322748
Ref: Library<109>-Footnote-314322814
Ref: Library<109>-Footnote-324322880
Ref: Library<109>-Footnote-334322946
Ref: Library<109>-Footnote-344323012
Ref: Library<109>-Footnote-354323078
Ref: Library<109>-Footnote-364323144
Ref: Library<109>-Footnote-374323210
Ref: Library<109>-Footnote-384323276
Ref: Library<109>-Footnote-394323342
Ref: Library<109>-Footnote-404323408
Ref: Library<109>-Footnote-414323474
Ref: Library<109>-Footnote-424323540
Ref: Library<109>-Footnote-434323606
Ref: Library<109>-Footnote-444323672
Ref: Library<109>-Footnote-454323738
Ref: Library<109>-Footnote-464323804
Ref: Library<109>-Footnote-474323870
Ref: Library<109>-Footnote-484323936
Ref: Library<109>-Footnote-494324002
Ref: Library<109>-Footnote-504324068
Ref: Library<109>-Footnote-514324134
Ref: Library<109>-Footnote-524324200
Ref: Library<109>-Footnote-534324266
Ref: Library<109>-Footnote-544324332
Ref: Library<109>-Footnote-554324398
Ref: Library<109>-Footnote-564324464
Ref: Library<109>-Footnote-574324530
Ref: Library<109>-Footnote-584324596
Ref: Library<109>-Footnote-594324662
Ref: Library<109>-Footnote-604324728
Ref: Library<109>-Footnote-614324794
Ref: Library<109>-Footnote-624324860
Ref: Library<109>-Footnote-634324926
Ref: Library<109>-Footnote-644324992
Ref: Library<109>-Footnote-654325058
Node: Documentation<40>4325124
Ref: whatsnew/changelog id5244325238
Ref: 1a904325238
Ref: Documentation<40>-Footnote-14325706
Ref: Documentation<40>-Footnote-24325771
Ref: Documentation<40>-Footnote-34325836
Node: Tests<43>4325901
Ref: whatsnew/changelog id5254326012
Ref: 1a914326012
Ref: Tests<43>-Footnote-14327222
Ref: Tests<43>-Footnote-24327287
Ref: Tests<43>-Footnote-34327352
Ref: Tests<43>-Footnote-44327417
Ref: Tests<43>-Footnote-54327482
Ref: Tests<43>-Footnote-64327547
Ref: Tests<43>-Footnote-74327612
Ref: Tests<43>-Footnote-84327677
Ref: Tests<43>-Footnote-94327742
Ref: Tests<43>-Footnote-104327807
Ref: Tests<43>-Footnote-114327873
Ref: Tests<43>-Footnote-124327939
Node: Build<47>4328005
Ref: whatsnew/changelog id5264328110
Ref: 1a924328110
Ref: Build<47>-Footnote-14329253
Ref: Build<47>-Footnote-24329318
Ref: Build<47>-Footnote-34329383
Ref: Build<47>-Footnote-44329448
Ref: Build<47>-Footnote-54329513
Ref: Build<47>-Footnote-64329578
Ref: Build<47>-Footnote-74329643
Node: Windows<40>4329708
Ref: whatsnew/changelog id5274329813
Ref: 1a934329813
Ref: Windows<40>-Footnote-14330107
Ref: Windows<40>-Footnote-24330172
Node: macOS<32>4330237
Ref: whatsnew/changelog id5284330341
Ref: 1a944330341
Ref: macOS<32>-Footnote-14331291
Ref: macOS<32>-Footnote-24331356
Ref: macOS<32>-Footnote-34331421
Ref: macOS<32>-Footnote-44331486
Ref: macOS<32>-Footnote-54331551
Node: IDLE<28>4331616
Ref: whatsnew/changelog id5294331724
Ref: 1a954331724
Ref: IDLE<28>-Footnote-14332146
Ref: IDLE<28>-Footnote-24332211
Ref: IDLE<28>-Footnote-34332276
Node: Tools/Demos<22>4332341
Ref: whatsnew/changelog id5304332449
Ref: 1a964332449
Ref: Tools/Demos<22>-Footnote-14332851
Ref: Tools/Demos<22>-Footnote-24332916
Node: C API<42>4332981
Ref: whatsnew/changelog id5314333072
Ref: 1a974333072
Ref: C API<42>-Footnote-14337839
Ref: C API<42>-Footnote-24337904
Ref: C API<42>-Footnote-34337971
Ref: C API<42>-Footnote-44338013
Ref: C API<42>-Footnote-54338080
Ref: C API<42>-Footnote-64338122
Ref: C API<42>-Footnote-74338189
Ref: C API<42>-Footnote-84338231
Ref: C API<42>-Footnote-94338298
Ref: C API<42>-Footnote-104338340
Ref: C API<42>-Footnote-114338408
Ref: C API<42>-Footnote-124338451
Ref: C API<42>-Footnote-134338519
Ref: C API<42>-Footnote-144338562
Ref: C API<42>-Footnote-154338630
Ref: C API<42>-Footnote-164338673
Ref: C API<42>-Footnote-174338739
Ref: C API<42>-Footnote-184338807
Ref: C API<42>-Footnote-194338850
Ref: C API<42>-Footnote-204338918
Ref: C API<42>-Footnote-214338961
Ref: C API<42>-Footnote-224339029
Ref: C API<42>-Footnote-234339072
Ref: C API<42>-Footnote-244339140
Ref: C API<42>-Footnote-254339183
Ref: C API<42>-Footnote-264339249
Ref: C API<42>-Footnote-274339315
Ref: C API<42>-Footnote-284339381
Ref: C API<42>-Footnote-294339447
Ref: C API<42>-Footnote-304339513
Ref: C API<42>-Footnote-314339579
Ref: C API<42>-Footnote-324339645
Ref: C API<42>-Footnote-334339713
Ref: C API<42>-Footnote-344339779
Ref: C API<42>-Footnote-354339845
Ref: C API<42>-Footnote-364339911
Node: Python 3 10 0 alpha 24339977
Ref: whatsnew/changelog python-3-10-0-alpha-24340104
Ref: 1a994340104
Node: Security<32>4340527
Ref: whatsnew/changelog id5324340628
Ref: 1a9a4340628
Ref: Security<32>-Footnote-14341104
Ref: Security<32>-Footnote-24341169
Node: Core and Builtins<108>4341234
Ref: whatsnew/changelog id5334341356
Ref: 1a9b4341356
Ref: Core and Builtins<108>-Footnote-14344711
Ref: Core and Builtins<108>-Footnote-24344776
Ref: Core and Builtins<108>-Footnote-34344841
Ref: Core and Builtins<108>-Footnote-44344906
Ref: Core and Builtins<108>-Footnote-54344971
Ref: Core and Builtins<108>-Footnote-64345036
Ref: Core and Builtins<108>-Footnote-74345101
Ref: Core and Builtins<108>-Footnote-84345166
Ref: Core and Builtins<108>-Footnote-94345231
Ref: Core and Builtins<108>-Footnote-104345296
Ref: Core and Builtins<108>-Footnote-114345362
Ref: Core and Builtins<108>-Footnote-124345428
Ref: Core and Builtins<108>-Footnote-134345494
Ref: Core and Builtins<108>-Footnote-144345560
Ref: Core and Builtins<108>-Footnote-154345626
Ref: Core and Builtins<108>-Footnote-164345692
Ref: Core and Builtins<108>-Footnote-174345758
Ref: Core and Builtins<108>-Footnote-184345824
Node: Library<110>4345890
Ref: whatsnew/changelog id5344346022
Ref: 1a9e4346022
Ref: Library<110>-Footnote-14346328
Node: Core and Builtins<109>4346393
Ref: whatsnew/changelog id5354346515
Ref: 1a9f4346515
Ref: Core and Builtins<109>-Footnote-14346843
Ref: Core and Builtins<109>-Footnote-24346908
Node: Library<111>4346950
Ref: whatsnew/changelog id5364347077
Ref: 1aa04347077
Ref: Library<111>-Footnote-14354116
Ref: Library<111>-Footnote-24354181
Ref: Library<111>-Footnote-34354246
Ref: Library<111>-Footnote-44354311
Ref: Library<111>-Footnote-54354376
Ref: Library<111>-Footnote-64354441
Ref: Library<111>-Footnote-74354506
Ref: Library<111>-Footnote-84354548
Ref: Library<111>-Footnote-94354613
Ref: Library<111>-Footnote-104354678
Ref: Library<111>-Footnote-114354744
Ref: Library<111>-Footnote-124354810
Ref: Library<111>-Footnote-134354876
Ref: Library<111>-Footnote-144354942
Ref: Library<111>-Footnote-154355008
Ref: Library<111>-Footnote-164355074
Ref: Library<111>-Footnote-174355140
Ref: Library<111>-Footnote-184355206
Ref: Library<111>-Footnote-194355272
Ref: Library<111>-Footnote-204355338
Ref: Library<111>-Footnote-214355404
Ref: Library<111>-Footnote-224355470
Ref: Library<111>-Footnote-234355536
Ref: Library<111>-Footnote-244355602
Ref: Library<111>-Footnote-254355668
Ref: Library<111>-Footnote-264355711
Ref: Library<111>-Footnote-274355777
Ref: Library<111>-Footnote-284355843
Ref: Library<111>-Footnote-294355909
Ref: Library<111>-Footnote-304355975
Ref: Library<111>-Footnote-314356041
Ref: Library<111>-Footnote-324356107
Ref: Library<111>-Footnote-334356173
Ref: Library<111>-Footnote-344356239
Ref: Library<111>-Footnote-354356305
Ref: Library<111>-Footnote-364356371
Ref: Library<111>-Footnote-374356436
Ref: Library<111>-Footnote-384356502
Ref: Library<111>-Footnote-394356568
Ref: Library<111>-Footnote-404356634
Ref: Library<111>-Footnote-414356700
Node: Documentation<41>4356766
Ref: whatsnew/changelog id5374356880
Ref: 1aa34356880
Ref: Documentation<41>-Footnote-14357730
Ref: Documentation<41>-Footnote-24357795
Ref: Documentation<41>-Footnote-34357860
Ref: Documentation<41>-Footnote-44357925
Ref: Documentation<41>-Footnote-54357990
Ref: Documentation<41>-Footnote-64358055
Node: Tests<44>4358120
Ref: whatsnew/changelog id5384358231
Ref: 1aa64358231
Ref: Tests<44>-Footnote-14358868
Ref: Tests<44>-Footnote-24358933
Ref: Tests<44>-Footnote-34358998
Ref: Tests<44>-Footnote-44359063
Node: Build<48>4359128
Ref: whatsnew/changelog id5394359233
Ref: 1aa74359233
Ref: Build<48>-Footnote-14359497
Node: Windows<41>4359562
Ref: whatsnew/changelog id5404359667
Ref: 1aa84359667
Ref: Windows<41>-Footnote-14360143
Ref: Windows<41>-Footnote-24360208
Ref: Windows<41>-Footnote-34360273
Ref: Windows<41>-Footnote-44360338
Ref: Windows<41>-Footnote-54360403
Node: macOS<33>4360468
Ref: whatsnew/changelog id5414360572
Ref: 1aa94360572
Ref: macOS<33>-Footnote-14360724
Node: IDLE<29>4360789
Ref: whatsnew/changelog id5424360891
Ref: 1aaa4360891
Ref: IDLE<29>-Footnote-14361506
Ref: IDLE<29>-Footnote-24361571
Ref: IDLE<29>-Footnote-34361636
Node: C API<43>4361701
Ref: whatsnew/changelog id5434361785
Ref: 1aab4361785
Ref: C API<43>-Footnote-14363120
Ref: C API<43>-Footnote-24363185
Ref: C API<43>-Footnote-34363250
Ref: C API<43>-Footnote-44363315
Ref: C API<43>-Footnote-54363380
Ref: C API<43>-Footnote-64363445
Ref: C API<43>-Footnote-74363510
Ref: C API<43>-Footnote-84363575
Node: Python 3 10 0 alpha 14363640
Ref: whatsnew/changelog python-3-10-0-alpha-14363765
Ref: 1aad4363765
Node: Security<33>4365098
Ref: whatsnew/changelog id5444365199
Ref: 1aae4365199
Ref: Security<33>-Footnote-14366102
Ref: Security<33>-Footnote-24366167
Ref: Security<33>-Footnote-34366232
Ref: Security<33>-Footnote-44366288
Ref: Security<33>-Footnote-54366353
Ref: Security<33>-Footnote-64366418
Ref: Security<33>-Footnote-74366474
Ref: Security<33>-Footnote-84366539
Node: Core and Builtins<110>4366604
Ref: whatsnew/changelog id5454366726
Ref: 1aaf4366726
Ref: Core and Builtins<110>-Footnote-14367418
Ref: Core and Builtins<110>-Footnote-24367483
Ref: Core and Builtins<110>-Footnote-34367548
Ref: Core and Builtins<110>-Footnote-44367590
Ref: Core and Builtins<110>-Footnote-54367655
Ref: Core and Builtins<110>-Footnote-64367720
Node: Library<112>4367762
Ref: whatsnew/changelog id5464367894
Ref: 1ab04367894
Ref: Library<112>-Footnote-14368077
Ref: Library<112>-Footnote-24368144
Node: Core and Builtins<111>4368186
Ref: whatsnew/changelog id5474368308
Ref: 1ab14368308
Ref: Core and Builtins<111>-Footnote-14368700
Ref: Core and Builtins<111>-Footnote-24368765
Node: Library<113>4368830
Ref: whatsnew/changelog id5484368962
Ref: 1ab24368962
Ref: Library<113>-Footnote-14369583
Ref: Library<113>-Footnote-24369650
Ref: Library<113>-Footnote-34369692
Ref: Library<113>-Footnote-44369759
Ref: Library<113>-Footnote-54369801
Ref: Library<113>-Footnote-64369868
Ref: Library<113>-Footnote-74369910
Ref: Library<113>-Footnote-84369977
Ref: Library<113>-Footnote-94370019
Node: Core and Builtins<112>4370086
Ref: whatsnew/changelog id5494370208
Ref: 1ab34370208
Ref: Core and Builtins<112>-Footnote-14370467
Node: Library<114>4370532
Ref: whatsnew/changelog id5504370664
Ref: 1ab44370664
Ref: Library<114>-Footnote-14371083
Ref: Library<114>-Footnote-24371150
Ref: Library<114>-Footnote-34371192
Ref: Library<114>-Footnote-44371259
Ref: Library<114>-Footnote-54371301
Ref: Library<114>-Footnote-64371368
Node: Core and Builtins<113>4371410
Ref: whatsnew/changelog id5514371532
Ref: 1ab54371532
Ref: Core and Builtins<113>-Footnote-14371786
Node: Library<115>4371851
Ref: whatsnew/changelog id5524371983
Ref: 1ab64371983
Ref: Library<115>-Footnote-14372283
Node: Core and Builtins<114>4372348
Ref: whatsnew/changelog id5534372470
Ref: 1ab74372470
Ref: Core and Builtins<114>-Footnote-14372913
Ref: Core and Builtins<114>-Footnote-24372978
Node: Library<116>4373043
Ref: whatsnew/changelog id5544373175
Ref: 1ab84373175
Ref: Library<116>-Footnote-14373365
Ref: Library<116>-Footnote-24373432
Node: Core and Builtins<115>4373474
Ref: whatsnew/changelog id5554373596
Ref: 1ab94373596
Ref: Core and Builtins<115>-Footnote-14374068
Node: Library<117>4374133
Ref: whatsnew/changelog id5564374265
Ref: 1aba4374265
Ref: Library<117>-Footnote-14374426
Node: Core and Builtins<116>4374491
Ref: whatsnew/changelog id5574374613
Ref: 1abb4374613
Ref: Core and Builtins<116>-Footnote-14374810
Node: Library<118>4374877
Ref: whatsnew/changelog id5584375009
Ref: 1abc4375009
Ref: Library<118>-Footnote-14375204
Ref: Library<118>-Footnote-24375271
Node: Core and Builtins<117>4375313
Ref: whatsnew/changelog id5594375435
Ref: 1abd4375435
Ref: Core and Builtins<117>-Footnote-14375911
Ref: Core and Builtins<117>-Footnote-24375976
Ref: Core and Builtins<117>-Footnote-34376041
Node: Library<119>4376106
Ref: whatsnew/changelog id5604376238
Ref: 1abe4376238
Ref: Library<119>-Footnote-14376459
Ref: Library<119>-Footnote-24376526
Node: Core and Builtins<118>4376568
Ref: whatsnew/changelog id5614376690
Ref: 1abf4376690
Ref: Core and Builtins<118>-Footnote-14378148
Ref: Core and Builtins<118>-Footnote-24378213
Ref: Core and Builtins<118>-Footnote-34378278
Ref: Core and Builtins<118>-Footnote-44378343
Ref: Core and Builtins<118>-Footnote-54378408
Ref: Core and Builtins<118>-Footnote-64378473
Ref: Core and Builtins<118>-Footnote-74378538
Ref: Core and Builtins<118>-Footnote-84378603
Ref: Core and Builtins<118>-Footnote-94378668
Ref: Core and Builtins<118>-Footnote-104378733
Ref: Core and Builtins<118>-Footnote-114378799
Node: Library<120>4378867
Ref: whatsnew/changelog id5624378999
Ref: 1ac04378999
Ref: Library<120>-Footnote-14379143
Node: Core and Builtins<119>4379210
Ref: whatsnew/changelog id5634379332
Ref: 1ac14379332
Ref: Core and Builtins<119>-Footnote-14379901
Ref: Core and Builtins<119>-Footnote-24379966
Node: Library<121>4380031
Ref: whatsnew/changelog id5644380163
Ref: 1ac24380163
Ref: Library<121>-Footnote-14380393
Ref: Library<121>-Footnote-24380460
Node: Core and Builtins<120>4380527
Ref: whatsnew/changelog id5654380649
Ref: 1ac34380649
Ref: Core and Builtins<120>-Footnote-14382625
Ref: Core and Builtins<120>-Footnote-24382690
Ref: Core and Builtins<120>-Footnote-34382755
Ref: Core and Builtins<120>-Footnote-44382820
Ref: Core and Builtins<120>-Footnote-54382885
Ref: Core and Builtins<120>-Footnote-64382950
Ref: Core and Builtins<120>-Footnote-74383015
Ref: Core and Builtins<120>-Footnote-84383080
Ref: Core and Builtins<120>-Footnote-94383145
Ref: Core and Builtins<120>-Footnote-104383210
Ref: Core and Builtins<120>-Footnote-114383276
Ref: Core and Builtins<120>-Footnote-124383342
Ref: Core and Builtins<120>-Footnote-134383408
Node: Library<122>4383474
Ref: whatsnew/changelog id5664383606
Ref: 1ac44383606
Ref: Library<122>-Footnote-14383757
Node: Core and Builtins<121>4383822
Ref: whatsnew/changelog id5674383944
Ref: 1ac54383944
Ref: Core and Builtins<121>-Footnote-14385062
Ref: Core and Builtins<121>-Footnote-24385127
Ref: Core and Builtins<121>-Footnote-34385192
Ref: Core and Builtins<121>-Footnote-44385234
Ref: Core and Builtins<121>-Footnote-54385301
Ref: Core and Builtins<121>-Footnote-64385366
Ref: Core and Builtins<121>-Footnote-74385431
Ref: Core and Builtins<121>-Footnote-84385498
Node: Library<123>4385563
Ref: whatsnew/changelog id5684385695
Ref: 1ac64385695
Ref: Library<123>-Footnote-14385909
Ref: Library<123>-Footnote-24385974
Node: Core and Builtins<122>4386016
Ref: whatsnew/changelog id5694386138
Ref: 1ac74386138
Ref: Core and Builtins<122>-Footnote-14391064
Ref: Core and Builtins<122>-Footnote-24391129
Ref: Core and Builtins<122>-Footnote-34391194
Ref: Core and Builtins<122>-Footnote-44391259
Ref: Core and Builtins<122>-Footnote-54391324
Ref: Core and Builtins<122>-Footnote-64391389
Ref: Core and Builtins<122>-Footnote-74391454
Ref: Core and Builtins<122>-Footnote-84391519
Ref: Core and Builtins<122>-Footnote-94391584
Ref: Core and Builtins<122>-Footnote-104391649
Ref: Core and Builtins<122>-Footnote-114391715
Ref: Core and Builtins<122>-Footnote-124391781
Ref: Core and Builtins<122>-Footnote-134391847
Ref: Core and Builtins<122>-Footnote-144391915
Ref: Core and Builtins<122>-Footnote-154391981
Ref: Core and Builtins<122>-Footnote-164392047
Ref: Core and Builtins<122>-Footnote-174392113
Ref: Core and Builtins<122>-Footnote-184392179
Ref: Core and Builtins<122>-Footnote-194392245
Ref: Core and Builtins<122>-Footnote-204392311
Ref: Core and Builtins<122>-Footnote-214392377
Ref: Core and Builtins<122>-Footnote-224392443
Ref: Core and Builtins<122>-Footnote-234392509
Ref: Core and Builtins<122>-Footnote-244392575
Ref: Core and Builtins<122>-Footnote-254392641
Ref: Core and Builtins<122>-Footnote-264392707
Node: Library<124>4392772
Ref: whatsnew/changelog id5704392904
Ref: 1acc4392904
Ref: Library<124>-Footnote-14393121
Ref: Library<124>-Footnote-24393188
Node: Core and Builtins<123>4393255
Ref: whatsnew/changelog id5714393377
Ref: 1acd4393377
Ref: Core and Builtins<123>-Footnote-14393964
Ref: Core and Builtins<123>-Footnote-24394029
Node: Library<125>4394094
Ref: whatsnew/changelog id5724394226
Ref: 1ace4394226
Ref: Library<125>-Footnote-14394594
Node: Core and Builtins<124>4394659
Ref: whatsnew/changelog id5734394781
Ref: 1acf4394781
Ref: Core and Builtins<124>-Footnote-14395125
Ref: Core and Builtins<124>-Footnote-24395190
Node: Library<126>4395255
Ref: whatsnew/changelog id5744395382
Ref: 1ad04395382
Ref: Library<126>-Footnote-14417549
Ref: Library<126>-Footnote-24417614
Ref: Library<126>-Footnote-34417679
Ref: Library<126>-Footnote-44417744
Ref: Library<126>-Footnote-54417809
Ref: Library<126>-Footnote-64417874
Ref: Library<126>-Footnote-74417939
Ref: Library<126>-Footnote-84418004
Ref: Library<126>-Footnote-94418069
Ref: Library<126>-Footnote-104418134
Ref: Library<126>-Footnote-114418200
Ref: Library<126>-Footnote-124418266
Ref: Library<126>-Footnote-134418332
Ref: Library<126>-Footnote-144418398
Ref: Library<126>-Footnote-154418464
Ref: Library<126>-Footnote-164418530
Ref: Library<126>-Footnote-174418583
Ref: Library<126>-Footnote-184418649
Ref: Library<126>-Footnote-194418715
Ref: Library<126>-Footnote-204418781
Ref: Library<126>-Footnote-214418849
Ref: Library<126>-Footnote-224418892
Ref: Library<126>-Footnote-234418960
Ref: Library<126>-Footnote-244419003
Ref: Library<126>-Footnote-254419069
Ref: Library<126>-Footnote-264419135
Ref: Library<126>-Footnote-274419201
Ref: Library<126>-Footnote-284419267
Ref: Library<126>-Footnote-294419333
Ref: Library<126>-Footnote-304419399
Ref: Library<126>-Footnote-314419465
Ref: Library<126>-Footnote-324419531
Ref: Library<126>-Footnote-334419597
Ref: Library<126>-Footnote-344419663
Ref: Library<126>-Footnote-354419729
Ref: Library<126>-Footnote-364419795
Ref: Library<126>-Footnote-374419861
Ref: Library<126>-Footnote-384419927
Ref: Library<126>-Footnote-394419993
Ref: Library<126>-Footnote-404420059
Ref: Library<126>-Footnote-414420125
Ref: Library<126>-Footnote-424420191
Ref: Library<126>-Footnote-434420257
Ref: Library<126>-Footnote-444420323
Ref: Library<126>-Footnote-454420389
Ref: Library<126>-Footnote-464420455
Ref: Library<126>-Footnote-474420521
Ref: Library<126>-Footnote-484420587
Ref: Library<126>-Footnote-494420653
Ref: Library<126>-Footnote-504420719
Ref: Library<126>-Footnote-514420785
Ref: Library<126>-Footnote-524420851
Ref: Library<126>-Footnote-534420917
Ref: Library<126>-Footnote-544420983
Ref: Library<126>-Footnote-554421049
Ref: Library<126>-Footnote-564421115
Ref: Library<126>-Footnote-574421181
Ref: Library<126>-Footnote-584421238
Ref: Library<126>-Footnote-594421304
Ref: Library<126>-Footnote-604421370
Ref: Library<126>-Footnote-614421436
Ref: Library<126>-Footnote-624421502
Ref: Library<126>-Footnote-634421568
Ref: Library<126>-Footnote-644421634
Ref: Library<126>-Footnote-654421700
Ref: Library<126>-Footnote-664421766
Ref: Library<126>-Footnote-674421832
Ref: Library<126>-Footnote-684421898
Ref: Library<126>-Footnote-694421964
Ref: Library<126>-Footnote-704422030
Ref: Library<126>-Footnote-714422096
Ref: Library<126>-Footnote-724422162
Ref: Library<126>-Footnote-734422228
Ref: Library<126>-Footnote-744422294
Ref: Library<126>-Footnote-754422360
Ref: Library<126>-Footnote-764422426
Ref: Library<126>-Footnote-774422492
Ref: Library<126>-Footnote-784422558
Ref: Library<126>-Footnote-794422624
Ref: Library<126>-Footnote-804422690
Ref: Library<126>-Footnote-814422756
Ref: Library<126>-Footnote-824422822
Ref: Library<126>-Footnote-834422888
Ref: Library<126>-Footnote-844422954
Ref: Library<126>-Footnote-854423020
Ref: Library<126>-Footnote-864423086
Ref: Library<126>-Footnote-874423152
Ref: Library<126>-Footnote-884423218
Ref: Library<126>-Footnote-894423284
Ref: Library<126>-Footnote-904423350
Ref: Library<126>-Footnote-914423416
Ref: Library<126>-Footnote-924423482
Ref: Library<126>-Footnote-934423548
Ref: Library<126>-Footnote-944423614
Ref: Library<126>-Footnote-954423680
Ref: Library<126>-Footnote-964423746
Ref: Library<126>-Footnote-974423812
Ref: Library<126>-Footnote-984423878
Ref: Library<126>-Footnote-994423944
Ref: Library<126>-Footnote-1004424010
Ref: Library<126>-Footnote-1014424077
Ref: Library<126>-Footnote-1024424144
Ref: Library<126>-Footnote-1034424211
Ref: Library<126>-Footnote-1044424278
Ref: Library<126>-Footnote-1054424345
Ref: Library<126>-Footnote-1064424412
Ref: Library<126>-Footnote-1074424479
Ref: Library<126>-Footnote-1084424546
Ref: Library<126>-Footnote-1094424613
Ref: Library<126>-Footnote-1104424680
Ref: Library<126>-Footnote-1114424747
Ref: Library<126>-Footnote-1124424814
Ref: Library<126>-Footnote-1134424881
Ref: Library<126>-Footnote-1144424948
Ref: Library<126>-Footnote-1154425015
Ref: Library<126>-Footnote-1164425082
Ref: Library<126>-Footnote-1174425149
Ref: Library<126>-Footnote-1184425216
Ref: Library<126>-Footnote-1194425283
Ref: Library<126>-Footnote-1204425350
Ref: Library<126>-Footnote-1214425416
Ref: Library<126>-Footnote-1224425483
Ref: Library<126>-Footnote-1234425550
Ref: Library<126>-Footnote-1244425617
Ref: Library<126>-Footnote-1254425684
Ref: Library<126>-Footnote-1264425728
Ref: Library<126>-Footnote-1274425795
Ref: Library<126>-Footnote-1284425862
Ref: Library<126>-Footnote-1294425929
Ref: Library<126>-Footnote-1304425996
Ref: Library<126>-Footnote-1314426063
Ref: Library<126>-Footnote-1324426130
Ref: Library<126>-Footnote-1334426197
Ref: Library<126>-Footnote-1344426264
Ref: Library<126>-Footnote-1354426331
Ref: Library<126>-Footnote-1364426398
Ref: Library<126>-Footnote-1374426465
Ref: Library<126>-Footnote-1384426532
Ref: Library<126>-Footnote-1394426599
Ref: Library<126>-Footnote-1404426666
Ref: Library<126>-Footnote-1414426733
Ref: Library<126>-Footnote-1424426800
Ref: Library<126>-Footnote-1434426867
Ref: Library<126>-Footnote-1444426934
Ref: Library<126>-Footnote-1454427001
Ref: Library<126>-Footnote-1464427068
Ref: Library<126>-Footnote-1474427135
Ref: Library<126>-Footnote-1484427202
Ref: Library<126>-Footnote-1494427269
Ref: Library<126>-Footnote-1504427336
Ref: Library<126>-Footnote-1514427403
Ref: Library<126>-Footnote-1524427470
Ref: Library<126>-Footnote-1534427537
Ref: Library<126>-Footnote-1544427604
Node: Documentation<42>4427671
Ref: whatsnew/changelog id5754427785
Ref: 1ad74427785
Ref: Documentation<42>-Footnote-14429552
Ref: Documentation<42>-Footnote-24429617
Ref: Documentation<42>-Footnote-34429659
Ref: Documentation<42>-Footnote-44429724
Ref: Documentation<42>-Footnote-54429789
Ref: Documentation<42>-Footnote-64429854
Ref: Documentation<42>-Footnote-74429919
Ref: Documentation<42>-Footnote-84429984
Ref: Documentation<42>-Footnote-94430049
Ref: Documentation<42>-Footnote-104430114
Ref: Documentation<42>-Footnote-114430180
Ref: Documentation<42>-Footnote-124430246
Ref: Documentation<42>-Footnote-134430312
Ref: Documentation<42>-Footnote-144430378
Node: Tests<45>4430444
Ref: whatsnew/changelog id5764430555
Ref: 1ad94430555
Ref: Tests<45>-Footnote-14432710
Ref: Tests<45>-Footnote-24432775
Ref: Tests<45>-Footnote-34432840
Ref: Tests<45>-Footnote-44432905
Ref: Tests<45>-Footnote-54432970
Ref: Tests<45>-Footnote-64433035
Ref: Tests<45>-Footnote-74433100
Ref: Tests<45>-Footnote-84433165
Ref: Tests<45>-Footnote-94433230
Ref: Tests<45>-Footnote-104433295
Ref: Tests<45>-Footnote-114433361
Ref: Tests<45>-Footnote-124433427
Ref: Tests<45>-Footnote-134433493
Ref: Tests<45>-Footnote-144433559
Ref: Tests<45>-Footnote-154433625
Ref: Tests<45>-Footnote-164433691
Node: Build<49>4433757
Ref: whatsnew/changelog id5774433862
Ref: 1adc4433862
Ref: Build<49>-Footnote-14434783
Ref: Build<49>-Footnote-24434848
Ref: Build<49>-Footnote-34434913
Ref: Build<49>-Footnote-44434978
Ref: Build<49>-Footnote-54435043
Ref: Build<49>-Footnote-64435108
Node: Windows<42>4435173
Ref: whatsnew/changelog id5784435278
Ref: 1add4435278
Ref: Windows<42>-Footnote-14437051
Ref: Windows<42>-Footnote-24437116
Ref: Windows<42>-Footnote-34437181
Ref: Windows<42>-Footnote-44437246
Ref: Windows<42>-Footnote-54437311
Ref: Windows<42>-Footnote-64437376
Ref: Windows<42>-Footnote-74437441
Ref: Windows<42>-Footnote-84437506
Ref: Windows<42>-Footnote-94437571
Ref: Windows<42>-Footnote-104437636
Ref: Windows<42>-Footnote-114437702
Ref: Windows<42>-Footnote-124437768
Ref: Windows<42>-Footnote-134437834
Ref: Windows<42>-Footnote-144437900
Node: macOS<34>4437966
Ref: whatsnew/changelog id5794438070
Ref: 1ade4438070
Ref: macOS<34>-Footnote-14438961
Ref: macOS<34>-Footnote-24439026
Ref: macOS<34>-Footnote-34439091
Ref: macOS<34>-Footnote-44439156
Ref: macOS<34>-Footnote-54439221
Ref: macOS<34>-Footnote-64439286
Node: IDLE<30>4439351
Ref: whatsnew/changelog id5804439453
Ref: 1adf4439453
Ref: IDLE<30>-Footnote-14440618
Ref: IDLE<30>-Footnote-24440683
Ref: IDLE<30>-Footnote-34440748
Ref: IDLE<30>-Footnote-44440813
Ref: IDLE<30>-Footnote-54440878
Ref: IDLE<30>-Footnote-64440943
Ref: IDLE<30>-Footnote-74441008
Ref: IDLE<30>-Footnote-84441073
Ref: IDLE<30>-Footnote-94441138
Ref: IDLE<30>-Footnote-104441203
Ref: IDLE<30>-Footnote-114441269
Node: C API<44>4441335
Ref: whatsnew/changelog id5814441419
Ref: 1ae04441419
Ref: C API<44>-Footnote-14446607
Ref: C API<44>-Footnote-24446672
Ref: C API<44>-Footnote-34446737
Ref: C API<44>-Footnote-44446802
Ref: C API<44>-Footnote-54446867
Ref: C API<44>-Footnote-64446932
Ref: C API<44>-Footnote-74446997
Ref: C API<44>-Footnote-84447062
Ref: C API<44>-Footnote-94447127
Ref: C API<44>-Footnote-104447192
Ref: C API<44>-Footnote-114447258
Ref: C API<44>-Footnote-124447324
Ref: C API<44>-Footnote-134447390
Ref: C API<44>-Footnote-144447456
Ref: C API<44>-Footnote-154447522
Ref: C API<44>-Footnote-164447588
Ref: C API<44>-Footnote-174447654
Ref: C API<44>-Footnote-184447720
Ref: C API<44>-Footnote-194447786
Ref: C API<44>-Footnote-204447852
Ref: C API<44>-Footnote-214447895
Ref: C API<44>-Footnote-224447961
Ref: C API<44>-Footnote-234448027
Ref: C API<44>-Footnote-244448093
Ref: C API<44>-Footnote-254448159
Ref: C API<44>-Footnote-264448225
Ref: C API<44>-Footnote-274448291
Ref: C API<44>-Footnote-284448357
Ref: C API<44>-Footnote-294448423
Node: Python 3 9 0 beta 14448489
Ref: whatsnew/changelog python-3-9-0-beta-14448613
Ref: 1aea4448613
Node: Security<34>4448976
Ref: whatsnew/changelog id5824449075
Ref: 1aeb4449075
Ref: Security<34>-Footnote-14449279
Node: Core and Builtins<125>4449344
Ref: whatsnew/changelog id5834449464
Ref: 1aec4449464
Ref: Core and Builtins<125>-Footnote-14452007
Ref: Core and Builtins<125>-Footnote-24452072
Ref: Core and Builtins<125>-Footnote-34452137
Ref: Core and Builtins<125>-Footnote-44452202
Ref: Core and Builtins<125>-Footnote-54452267
Ref: Core and Builtins<125>-Footnote-64452332
Ref: Core and Builtins<125>-Footnote-74452374
Ref: Core and Builtins<125>-Footnote-84452439
Ref: Core and Builtins<125>-Footnote-94452504
Ref: Core and Builtins<125>-Footnote-104452571
Ref: Core and Builtins<125>-Footnote-114452614
Ref: Core and Builtins<125>-Footnote-124452680
Ref: Core and Builtins<125>-Footnote-134452748
Ref: Core and Builtins<125>-Footnote-144452791
Ref: Core and Builtins<125>-Footnote-154452857
Ref: Core and Builtins<125>-Footnote-164452923
Ref: Core and Builtins<125>-Footnote-174452989
Ref: Core and Builtins<125>-Footnote-184453055
Ref: Core and Builtins<125>-Footnote-194453123
Ref: Core and Builtins<125>-Footnote-204453166
Ref: Core and Builtins<125>-Footnote-214453232
Ref: Core and Builtins<125>-Footnote-224453298
Ref: Core and Builtins<125>-Footnote-234453364
Ref: Core and Builtins<125>-Footnote-244453430
Node: Library<127>4453496
Ref: whatsnew/changelog id5844453621
Ref: 1aee4453621
Ref: Library<127>-Footnote-14461014
Ref: Library<127>-Footnote-24461079
Ref: Library<127>-Footnote-34461144
Ref: Library<127>-Footnote-44461209
Ref: Library<127>-Footnote-54461274
Ref: Library<127>-Footnote-64461339
Ref: Library<127>-Footnote-74461404
Ref: Library<127>-Footnote-84461469
Ref: Library<127>-Footnote-94461534
Ref: Library<127>-Footnote-104461599
Ref: Library<127>-Footnote-114461665
Ref: Library<127>-Footnote-124461731
Ref: Library<127>-Footnote-134461797
Ref: Library<127>-Footnote-144461863
Ref: Library<127>-Footnote-154461929
Ref: Library<127>-Footnote-164461972
Ref: Library<127>-Footnote-174462038
Ref: Library<127>-Footnote-184462104
Ref: Library<127>-Footnote-194462170
Ref: Library<127>-Footnote-204462236
Ref: Library<127>-Footnote-214462302
Ref: Library<127>-Footnote-224462368
Ref: Library<127>-Footnote-234462434
Ref: Library<127>-Footnote-244462500
Ref: Library<127>-Footnote-254462566
Ref: Library<127>-Footnote-264462632
Ref: Library<127>-Footnote-274462698
Ref: Library<127>-Footnote-284462764
Ref: Library<127>-Footnote-294462830
Ref: Library<127>-Footnote-304462896
Ref: Library<127>-Footnote-314462962
Ref: Library<127>-Footnote-324463028
Ref: Library<127>-Footnote-334463094
Ref: Library<127>-Footnote-344463160
Ref: Library<127>-Footnote-354463226
Ref: Library<127>-Footnote-364463292
Ref: Library<127>-Footnote-374463358
Ref: Library<127>-Footnote-384463424
Ref: Library<127>-Footnote-394463490
Ref: Library<127>-Footnote-404463556
Ref: Library<127>-Footnote-414463622
Ref: Library<127>-Footnote-424463688
Ref: Library<127>-Footnote-434463754
Ref: Library<127>-Footnote-444463820
Ref: Library<127>-Footnote-454463886
Ref: Library<127>-Footnote-464463952
Ref: Library<127>-Footnote-474464018
Ref: Library<127>-Footnote-484464084
Ref: Library<127>-Footnote-494464150
Ref: Library<127>-Footnote-504464216
Node: Documentation<43>4464282
Ref: whatsnew/changelog id5854464394
Ref: 1af34464394
Ref: Documentation<43>-Footnote-14465063
Ref: Documentation<43>-Footnote-24465128
Ref: Documentation<43>-Footnote-34465193
Ref: Documentation<43>-Footnote-44465258
Ref: Documentation<43>-Footnote-54465323
Node: Tests<46>4465388
Ref: whatsnew/changelog id5864465497
Ref: 1af44465497
Ref: Tests<46>-Footnote-14465852
Ref: Tests<46>-Footnote-24465917
Node: Build<50>4465982
Ref: whatsnew/changelog id5874466085
Ref: 1af54466085
Ref: Build<50>-Footnote-14466425
Ref: Build<50>-Footnote-24466490
Node: Windows<43>4466555
Ref: whatsnew/changelog id5884466658
Ref: 1af64466658
Ref: Windows<43>-Footnote-14467113
Ref: Windows<43>-Footnote-24467178
Ref: Windows<43>-Footnote-34467243
Node: macOS<35>4467308
Ref: whatsnew/changelog id5894467417
Ref: 1af74467417
Ref: macOS<35>-Footnote-14468040
Ref: macOS<35>-Footnote-24468105
Node: Tools/Demos<23>4468170
Ref: whatsnew/changelog id5904468277
Ref: 1af84468277
Ref: Tools/Demos<23>-Footnote-14468762
Ref: Tools/Demos<23>-Footnote-24468827
Ref: Tools/Demos<23>-Footnote-34468892
Node: C API<45>4468957
Ref: whatsnew/changelog id5914469046
Ref: 1af94469046
Ref: C API<45>-Footnote-14471072
Ref: C API<45>-Footnote-24471137
Ref: C API<45>-Footnote-34471202
Ref: C API<45>-Footnote-44471267
Ref: C API<45>-Footnote-54471332
Ref: C API<45>-Footnote-64471397
Ref: C API<45>-Footnote-74471462
Ref: C API<45>-Footnote-84471527
Ref: C API<45>-Footnote-94471592
Ref: C API<45>-Footnote-104471657
Ref: C API<45>-Footnote-114471723
Node: Python 3 9 0 alpha 64471766
Ref: whatsnew/changelog python-3-9-0-alpha-64471889
Ref: 1afa4471889
Node: Security<35>4472272
Ref: whatsnew/changelog id5924472372
Ref: 1afb4472372
Ref: Security<35>-Footnote-14473020
Ref: Security<35>-Footnote-24473085
Ref: Security<35>-Footnote-34473150
Ref: Security<35>-Footnote-44473215
Node: Core and Builtins<126>4473270
Ref: whatsnew/changelog id5934473391
Ref: 1afc4473391
Ref: Core and Builtins<126>-Footnote-14477164
Ref: Core and Builtins<126>-Footnote-24477229
Ref: Core and Builtins<126>-Footnote-34477294
Ref: Core and Builtins<126>-Footnote-44477359
Ref: Core and Builtins<126>-Footnote-54477424
Ref: Core and Builtins<126>-Footnote-64477489
Ref: Core and Builtins<126>-Footnote-74477554
Ref: Core and Builtins<126>-Footnote-84477619
Ref: Core and Builtins<126>-Footnote-94477684
Ref: Core and Builtins<126>-Footnote-104477749
Ref: Core and Builtins<126>-Footnote-114477792
Ref: Core and Builtins<126>-Footnote-124477858
Ref: Core and Builtins<126>-Footnote-134477926
Ref: Core and Builtins<126>-Footnote-144477969
Ref: Core and Builtins<126>-Footnote-154478037
Ref: Core and Builtins<126>-Footnote-164478080
Ref: Core and Builtins<126>-Footnote-174478148
Ref: Core and Builtins<126>-Footnote-184478191
Ref: Core and Builtins<126>-Footnote-194478257
Ref: Core and Builtins<126>-Footnote-204478323
Ref: Core and Builtins<126>-Footnote-214478391
Ref: Core and Builtins<126>-Footnote-224478459
Ref: Core and Builtins<126>-Footnote-234478525
Ref: Core and Builtins<126>-Footnote-244478593
Ref: Core and Builtins<126>-Footnote-254478636
Ref: Core and Builtins<126>-Footnote-264478704
Ref: Core and Builtins<126>-Footnote-274478747
Ref: Core and Builtins<126>-Footnote-284478813
Ref: Core and Builtins<126>-Footnote-294478879
Ref: Core and Builtins<126>-Footnote-304478922
Ref: Core and Builtins<126>-Footnote-314478988
Ref: Core and Builtins<126>-Footnote-324479054
Ref: Core and Builtins<126>-Footnote-334479120
Node: Library<128>4479163
Ref: whatsnew/changelog id5944479289
Ref: 1afd4479289
Ref: Library<128>-Footnote-14489557
Ref: Library<128>-Footnote-24489622
Ref: Library<128>-Footnote-34489687
Ref: Library<128>-Footnote-44489752
Ref: Library<128>-Footnote-54489817
Ref: Library<128>-Footnote-64489882
Ref: Library<128>-Footnote-74489924
Ref: Library<128>-Footnote-84489989
Ref: Library<128>-Footnote-94490054
Ref: Library<128>-Footnote-104490119
Ref: Library<128>-Footnote-114490185
Ref: Library<128>-Footnote-124490251
Ref: Library<128>-Footnote-134490317
Ref: Library<128>-Footnote-144490383
Ref: Library<128>-Footnote-154490449
Ref: Library<128>-Footnote-164490515
Ref: Library<128>-Footnote-174490581
Ref: Library<128>-Footnote-184490647
Ref: Library<128>-Footnote-194490713
Ref: Library<128>-Footnote-204490779
Ref: Library<128>-Footnote-214490845
Ref: Library<128>-Footnote-224490911
Ref: Library<128>-Footnote-234490977
Ref: Library<128>-Footnote-244491043
Ref: Library<128>-Footnote-254491109
Ref: Library<128>-Footnote-264491175
Ref: Library<128>-Footnote-274491241
Ref: Library<128>-Footnote-284491307
Ref: Library<128>-Footnote-294491373
Ref: Library<128>-Footnote-304491439
Ref: Library<128>-Footnote-314491505
Ref: Library<128>-Footnote-324491571
Ref: Library<128>-Footnote-334491637
Ref: Library<128>-Footnote-344491703
Ref: Library<128>-Footnote-354491769
Ref: Library<128>-Footnote-364491835
Ref: Library<128>-Footnote-374491901
Ref: Library<128>-Footnote-384491967
Ref: Library<128>-Footnote-394492033
Ref: Library<128>-Footnote-404492099
Ref: Library<128>-Footnote-414492165
Ref: Library<128>-Footnote-424492231
Ref: Library<128>-Footnote-434492297
Ref: Library<128>-Footnote-444492363
Ref: Library<128>-Footnote-454492429
Ref: Library<128>-Footnote-464492495
Ref: Library<128>-Footnote-474492561
Ref: Library<128>-Footnote-484492627
Ref: Library<128>-Footnote-494492670
Ref: Library<128>-Footnote-504492736
Ref: Library<128>-Footnote-514492779
Ref: Library<128>-Footnote-524492845
Ref: Library<128>-Footnote-534492911
Ref: Library<128>-Footnote-544492977
Ref: Library<128>-Footnote-554493020
Ref: Library<128>-Footnote-564493086
Ref: Library<128>-Footnote-574493152
Ref: Library<128>-Footnote-584493218
Ref: Library<128>-Footnote-594493284
Ref: Library<128>-Footnote-604493350
Ref: Library<128>-Footnote-614493416
Node: Documentation<44>4493482
Ref: whatsnew/changelog id5954493595
Ref: 1b024493595
Ref: Documentation<44>-Footnote-14494170
Ref: Documentation<44>-Footnote-24494235
Ref: Documentation<44>-Footnote-34494300
Ref: Documentation<44>-Footnote-44494365
Node: Tests<47>4494430
Ref: whatsnew/changelog id5964494540
Ref: 1b054494540
Ref: Tests<47>-Footnote-14495621
Ref: Tests<47>-Footnote-24495686
Ref: Tests<47>-Footnote-34495751
Ref: Tests<47>-Footnote-44495816
Ref: Tests<47>-Footnote-54495881
Ref: Tests<47>-Footnote-64495946
Ref: Tests<47>-Footnote-74496011
Ref: Tests<47>-Footnote-84496070
Ref: Tests<47>-Footnote-94496135
Node: Build<51>4496199
Ref: whatsnew/changelog id5974496303
Ref: 1b074496303
Ref: Build<51>-Footnote-14496724
Ref: Build<51>-Footnote-24496789
Ref: Build<51>-Footnote-34496854
Node: Windows<44>4496919
Ref: whatsnew/changelog id5984497023
Ref: 1b084497023
Ref: Windows<44>-Footnote-14497236
Ref: Windows<44>-Footnote-24497301
Node: macOS<36>4497365
Ref: whatsnew/changelog id5994497468
Ref: 1b094497468
Ref: macOS<36>-Footnote-14497924
Ref: macOS<36>-Footnote-24497989
Node: IDLE<31>4498054
Ref: whatsnew/changelog id6004498161
Ref: 1b0a4498161
Ref: IDLE<31>-Footnote-14498505
Ref: IDLE<31>-Footnote-24498570
Node: Tools/Demos<24>4498635
Ref: whatsnew/changelog id6014498742
Ref: 1b0b4498742
Ref: Tools/Demos<24>-Footnote-14499209
Ref: Tools/Demos<24>-Footnote-24499274
Ref: Tools/Demos<24>-Footnote-34499339
Node: C API<46>4499404
Ref: whatsnew/changelog id6024499494
Ref: 1b0c4499494
Ref: C API<46>-Footnote-14501469
Ref: C API<46>-Footnote-24501534
Ref: C API<46>-Footnote-34501599
Ref: C API<46>-Footnote-44501664
Ref: C API<46>-Footnote-54501729
Ref: C API<46>-Footnote-64501794
Ref: C API<46>-Footnote-74501859
Ref: C API<46>-Footnote-84501924
Ref: C API<46>-Footnote-94501989
Node: Python 3 9 0 alpha 54502054
Ref: whatsnew/changelog python-3-9-0-alpha-54502178
Ref: 1b0d4502178
Node: Security<36>4502561
Ref: whatsnew/changelog id6034502661
Ref: 1b0e4502661
Ref: Security<36>-Footnote-14502945
Ref: Security<36>-Footnote-24503010
Node: Core and Builtins<127>4503066
Ref: whatsnew/changelog id6044503187
Ref: 1b0f4503187
Ref: Core and Builtins<127>-Footnote-14509045
Ref: Core and Builtins<127>-Footnote-24509110
Ref: Core and Builtins<127>-Footnote-34509177
Ref: Core and Builtins<127>-Footnote-44509219
Ref: Core and Builtins<127>-Footnote-54509286
Ref: Core and Builtins<127>-Footnote-64509328
Ref: Core and Builtins<127>-Footnote-74509393
Ref: Core and Builtins<127>-Footnote-84509458
Ref: Core and Builtins<127>-Footnote-94509525
Ref: Core and Builtins<127>-Footnote-104509592
Ref: Core and Builtins<127>-Footnote-114509635
Ref: Core and Builtins<127>-Footnote-124509701
Ref: Core and Builtins<127>-Footnote-134509744
Ref: Core and Builtins<127>-Footnote-144509810
Ref: Core and Builtins<127>-Footnote-154509876
Ref: Core and Builtins<127>-Footnote-164509919
Ref: Core and Builtins<127>-Footnote-174509987
Ref: Core and Builtins<127>-Footnote-184510030
Ref: Core and Builtins<127>-Footnote-194510096
Ref: Core and Builtins<127>-Footnote-204510162
Ref: Core and Builtins<127>-Footnote-214510228
Ref: Core and Builtins<127>-Footnote-224510294
Ref: Core and Builtins<127>-Footnote-234510337
Ref: Core and Builtins<127>-Footnote-244510403
Ref: Core and Builtins<127>-Footnote-254510469
Ref: Core and Builtins<127>-Footnote-264510535
Ref: Core and Builtins<127>-Footnote-274510601
Ref: Core and Builtins<127>-Footnote-284510667
Ref: Core and Builtins<127>-Footnote-294510733
Ref: Core and Builtins<127>-Footnote-304510799
Ref: Core and Builtins<127>-Footnote-314510865
Ref: Core and Builtins<127>-Footnote-324510933
Ref: Core and Builtins<127>-Footnote-334510976
Ref: Core and Builtins<127>-Footnote-344511042
Ref: Core and Builtins<127>-Footnote-354511085
Ref: Core and Builtins<127>-Footnote-364511151
Ref: Core and Builtins<127>-Footnote-374511219
Ref: Core and Builtins<127>-Footnote-384511262
Ref: Core and Builtins<127>-Footnote-394511328
Ref: Core and Builtins<127>-Footnote-404511394
Ref: Core and Builtins<127>-Footnote-414511460
Ref: Core and Builtins<127>-Footnote-424511526
Node: Library<129>4511592
Ref: whatsnew/changelog id6054511718
Ref: 1b104511718
Ref: Library<129>-Footnote-14520891
Ref: Library<129>-Footnote-24520956
Ref: Library<129>-Footnote-34521021
Ref: Library<129>-Footnote-44521086
Ref: Library<129>-Footnote-54521151
Ref: Library<129>-Footnote-64521216
Ref: Library<129>-Footnote-74521281
Ref: Library<129>-Footnote-84521346
Ref: Library<129>-Footnote-94521411
Ref: Library<129>-Footnote-104521476
Ref: Library<129>-Footnote-114521542
Ref: Library<129>-Footnote-124521608
Ref: Library<129>-Footnote-134521651
Ref: Library<129>-Footnote-144521717
Ref: Library<129>-Footnote-154521783
Ref: Library<129>-Footnote-164521849
Ref: Library<129>-Footnote-174521892
Ref: Library<129>-Footnote-184521958
Ref: Library<129>-Footnote-194522024
Ref: Library<129>-Footnote-204522090
Ref: Library<129>-Footnote-214522156
Ref: Library<129>-Footnote-224522222
Ref: Library<129>-Footnote-234522288
Ref: Library<129>-Footnote-244522354
Ref: Library<129>-Footnote-254522420
Ref: Library<129>-Footnote-264522486
Ref: Library<129>-Footnote-274522552
Ref: Library<129>-Footnote-284522618
Ref: Library<129>-Footnote-294522684
Ref: Library<129>-Footnote-304522750
Ref: Library<129>-Footnote-314522816
Ref: Library<129>-Footnote-324522882
Ref: Library<129>-Footnote-334522925
Ref: Library<129>-Footnote-344522991
Ref: Library<129>-Footnote-354523057
Ref: Library<129>-Footnote-364523123
Ref: Library<129>-Footnote-374523189
Ref: Library<129>-Footnote-384523255
Ref: Library<129>-Footnote-394523321
Ref: Library<129>-Footnote-404523364
Ref: Library<129>-Footnote-414523430
Ref: Library<129>-Footnote-424523496
Ref: Library<129>-Footnote-434523562
Ref: Library<129>-Footnote-444523628
Ref: Library<129>-Footnote-454523694
Ref: Library<129>-Footnote-464523760
Ref: Library<129>-Footnote-474523826
Ref: Library<129>-Footnote-484523892
Ref: Library<129>-Footnote-494523958
Ref: Library<129>-Footnote-504524024
Ref: Library<129>-Footnote-514524090
Ref: Library<129>-Footnote-524524156
Ref: Library<129>-Footnote-534524222
Ref: Library<129>-Footnote-544524288
Node: Documentation<45>4524354
Ref: whatsnew/changelog id6064524467
Ref: 1b164524467
Ref: Documentation<45>-Footnote-14525109
Ref: Documentation<45>-Footnote-24525174
Ref: Documentation<45>-Footnote-34525216
Ref: Documentation<45>-Footnote-44525281
Ref: Documentation<45>-Footnote-54525346
Ref: Documentation<45>-Footnote-64525411
Ref: Documentation<45>-Footnote-74525476
Node: Tests<48>4525541
Ref: whatsnew/changelog id6074525651
Ref: 1b174525651
Ref: Tests<48>-Footnote-14526337
Ref: Tests<48>-Footnote-24526402
Ref: Tests<48>-Footnote-34526467
Ref: Tests<48>-Footnote-44526532
Node: Build<52>4526597
Ref: whatsnew/changelog id6084526701
Ref: 1b184526701
Ref: Build<52>-Footnote-14527571
Ref: Build<52>-Footnote-24527636
Ref: Build<52>-Footnote-34527701
Node: Windows<45>4527768
Ref: whatsnew/changelog id6094527872
Ref: 1b194527872
Ref: Windows<45>-Footnote-14528754
Ref: Windows<45>-Footnote-24528819
Ref: Windows<45>-Footnote-34528884
Ref: Windows<45>-Footnote-44528949
Ref: Windows<45>-Footnote-54529014
Ref: Windows<45>-Footnote-64529079
Node: macOS<37>4529144
Ref: whatsnew/changelog id6104529247
Ref: 1b1a4529247
Ref: macOS<37>-Footnote-14529377
Node: IDLE<32>4529442
Ref: whatsnew/changelog id6114529549
Ref: 1b1b4529549
Ref: IDLE<32>-Footnote-14530111
Ref: IDLE<32>-Footnote-24530176
Ref: IDLE<32>-Footnote-34530241
Ref: IDLE<32>-Footnote-44530306
Node: Tools/Demos<25>4530371
Ref: whatsnew/changelog id6124530478
Ref: 1b1c4530478
Ref: Tools/Demos<25>-Footnote-14531015
Ref: Tools/Demos<25>-Footnote-24531080
Node: C API<47>4531145
Ref: whatsnew/changelog id6134531235
Ref: 1b1d4531235
Ref: C API<47>-Footnote-14534787
Ref: C API<47>-Footnote-24534852
Ref: C API<47>-Footnote-34534917
Ref: C API<47>-Footnote-44534982
Ref: C API<47>-Footnote-54535047
Ref: C API<47>-Footnote-64535112
Ref: C API<47>-Footnote-74535177
Ref: C API<47>-Footnote-84535242
Ref: C API<47>-Footnote-94535307
Ref: C API<47>-Footnote-104535372
Ref: C API<47>-Footnote-114535438
Ref: C API<47>-Footnote-124535504
Ref: C API<47>-Footnote-134535570
Ref: C API<47>-Footnote-144535636
Ref: C API<47>-Footnote-154535702
Ref: C API<47>-Footnote-164535768
Ref: C API<47>-Footnote-174535834
Node: Python 3 9 0 alpha 44535900
Ref: whatsnew/changelog python-3-9-0-alpha-44536024
Ref: 1b224536024
Node: Security<37>4536355
Ref: whatsnew/changelog id6144536455
Ref: 1b234536455
Ref: Security<37>-Footnote-14536866
Ref: Security<37>-Footnote-24536931
Ref: Security<37>-Footnote-34536996
Node: Core and Builtins<128>4537061
Ref: whatsnew/changelog id6154537182
Ref: 1b244537182
Ref: Core and Builtins<128>-Footnote-14540595
Ref: Core and Builtins<128>-Footnote-24540660
Ref: Core and Builtins<128>-Footnote-34540725
Ref: Core and Builtins<128>-Footnote-44540790
Ref: Core and Builtins<128>-Footnote-54540855
Ref: Core and Builtins<128>-Footnote-64540920
Ref: Core and Builtins<128>-Footnote-74540985
Ref: Core and Builtins<128>-Footnote-84541050
Ref: Core and Builtins<128>-Footnote-94541117
Ref: Core and Builtins<128>-Footnote-104541159
Ref: Core and Builtins<128>-Footnote-114541227
Ref: Core and Builtins<128>-Footnote-124541270
Ref: Core and Builtins<128>-Footnote-134541336
Ref: Core and Builtins<128>-Footnote-144541402
Ref: Core and Builtins<128>-Footnote-154541468
Ref: Core and Builtins<128>-Footnote-164541534
Ref: Core and Builtins<128>-Footnote-174541600
Ref: Core and Builtins<128>-Footnote-184541668
Ref: Core and Builtins<128>-Footnote-194541711
Ref: Core and Builtins<128>-Footnote-204541779
Ref: Core and Builtins<128>-Footnote-214541822
Ref: Core and Builtins<128>-Footnote-224541890
Ref: Core and Builtins<128>-Footnote-234541933
Ref: Core and Builtins<128>-Footnote-244541999
Ref: Core and Builtins<128>-Footnote-254542065
Ref: Core and Builtins<128>-Footnote-264542131
Ref: Core and Builtins<128>-Footnote-274542197
Ref: Core and Builtins<128>-Footnote-284542263
Ref: Core and Builtins<128>-Footnote-294542329
Node: Library<130>4542395
Ref: whatsnew/changelog id6164542521
Ref: 1b274542521
Ref: Library<130>-Footnote-14548704
Ref: Library<130>-Footnote-24548769
Ref: Library<130>-Footnote-34548834
Ref: Library<130>-Footnote-44548899
Ref: Library<130>-Footnote-54548964
Ref: Library<130>-Footnote-64549029
Ref: Library<130>-Footnote-74549094
Ref: Library<130>-Footnote-84549159
Ref: Library<130>-Footnote-94549224
Ref: Library<130>-Footnote-104549289
Ref: Library<130>-Footnote-114549355
Ref: Library<130>-Footnote-124549421
Ref: Library<130>-Footnote-134549487
Ref: Library<130>-Footnote-144549553
Ref: Library<130>-Footnote-154549619
Ref: Library<130>-Footnote-164549685
Ref: Library<130>-Footnote-174549767
Ref: Library<130>-Footnote-184549833
Ref: Library<130>-Footnote-194549899
Ref: Library<130>-Footnote-204549965
Ref: Library<130>-Footnote-214550031
Ref: Library<130>-Footnote-224550097
Ref: Library<130>-Footnote-234550163
Ref: Library<130>-Footnote-244550229
Ref: Library<130>-Footnote-254550295
Ref: Library<130>-Footnote-264550361
Ref: Library<130>-Footnote-274550427
Ref: Library<130>-Footnote-284550470
Ref: Library<130>-Footnote-294550536
Ref: Library<130>-Footnote-304550602
Ref: Library<130>-Footnote-314550668
Ref: Library<130>-Footnote-324550734
Ref: Library<130>-Footnote-334550800
Ref: Library<130>-Footnote-344550866
Ref: Library<130>-Footnote-354550932
Ref: Library<130>-Footnote-364550998
Ref: Library<130>-Footnote-374551064
Ref: Library<130>-Footnote-384551130
Ref: Library<130>-Footnote-394551196
Node: Documentation<46>4551262
Ref: whatsnew/changelog id6174551375
Ref: 1b294551375
Ref: Documentation<46>-Footnote-14552416
Ref: Documentation<46>-Footnote-24552481
Ref: Documentation<46>-Footnote-34552546
Ref: Documentation<46>-Footnote-44552611
Ref: Documentation<46>-Footnote-54552676
Ref: Documentation<46>-Footnote-64552741
Ref: Documentation<46>-Footnote-74552806
Node: Tests<49>4552870
Ref: whatsnew/changelog id6184552980
Ref: 1b2a4552980
Ref: Tests<49>-Footnote-14553314
Ref: Tests<49>-Footnote-24553379
Node: Build<53>4553444
Ref: whatsnew/changelog id6194553548
Ref: 1b2b4553548
Ref: Build<53>-Footnote-14553678
Node: Windows<46>4553743
Ref: whatsnew/changelog id6204553846
Ref: 1b2c4553846
Ref: Windows<46>-Footnote-14554652
Ref: Windows<46>-Footnote-24554717
Ref: Windows<46>-Footnote-34554782
Ref: Windows<46>-Footnote-44554847
Ref: Windows<46>-Footnote-54554912
Ref: Windows<46>-Footnote-64554977
Node: IDLE<33>4555042
Ref: whatsnew/changelog id6214555145
Ref: 1b2d4555145
Ref: IDLE<33>-Footnote-14555692
Ref: IDLE<33>-Footnote-24555757
Ref: IDLE<33>-Footnote-34555822
Ref: IDLE<33>-Footnote-44555887
Ref: IDLE<33>-Footnote-54555952
Node: C API<48>4556017
Ref: whatsnew/changelog id6224556100
Ref: 1b2e4556100
Ref: C API<48>-Footnote-14558759
Ref: C API<48>-Footnote-24558824
Ref: C API<48>-Footnote-34558889
Ref: C API<48>-Footnote-44558954
Ref: C API<48>-Footnote-54559019
Ref: C API<48>-Footnote-64559084
Ref: C API<48>-Footnote-74559149
Ref: C API<48>-Footnote-84559214
Ref: C API<48>-Footnote-94559279
Ref: C API<48>-Footnote-104559344
Ref: C API<48>-Footnote-114559410
Ref: C API<48>-Footnote-124559476
Node: Python 3 9 0 alpha 34559542
Ref: whatsnew/changelog python-3-9-0-alpha-34559666
Ref: 1b334559666
Node: Core and Builtins<129>4559927
Ref: whatsnew/changelog id6234560027
Ref: 1b344560027
Ref: Core and Builtins<129>-Footnote-14564131
Ref: Core and Builtins<129>-Footnote-24564196
Ref: Core and Builtins<129>-Footnote-34564261
Ref: Core and Builtins<129>-Footnote-44564326
Ref: Core and Builtins<129>-Footnote-54564391
Ref: Core and Builtins<129>-Footnote-64564456
Ref: Core and Builtins<129>-Footnote-74564521
Ref: Core and Builtins<129>-Footnote-84564586
Ref: Core and Builtins<129>-Footnote-94564651
Ref: Core and Builtins<129>-Footnote-104564716
Ref: Core and Builtins<129>-Footnote-114564782
Ref: Core and Builtins<129>-Footnote-124564850
Ref: Core and Builtins<129>-Footnote-134564893
Ref: Core and Builtins<129>-Footnote-144564959
Ref: Core and Builtins<129>-Footnote-154565025
Ref: Core and Builtins<129>-Footnote-164565091
Ref: Core and Builtins<129>-Footnote-174565157
Ref: Core and Builtins<129>-Footnote-184565223
Ref: Core and Builtins<129>-Footnote-194565289
Ref: Core and Builtins<129>-Footnote-204565355
Ref: Core and Builtins<129>-Footnote-214565421
Ref: Core and Builtins<129>-Footnote-224565487
Ref: Core and Builtins<129>-Footnote-234565553
Ref: Core and Builtins<129>-Footnote-244565619
Node: Library<131>4565685
Ref: whatsnew/changelog id6244565811
Ref: 1b384565811
Ref: Library<131>-Footnote-14575419
Ref: Library<131>-Footnote-24575484
Ref: Library<131>-Footnote-34575549
Ref: Library<131>-Footnote-44575614
Ref: Library<131>-Footnote-54575679
Ref: Library<131>-Footnote-64575744
Ref: Library<131>-Footnote-74575809
Ref: Library<131>-Footnote-84575874
Ref: Library<131>-Footnote-94575939
Ref: Library<131>-Footnote-104576004
Ref: Library<131>-Footnote-114576070
Ref: Library<131>-Footnote-124576136
Ref: Library<131>-Footnote-134576202
Ref: Library<131>-Footnote-144576268
Ref: Library<131>-Footnote-154576334
Ref: Library<131>-Footnote-164576400
Ref: Library<131>-Footnote-174576466
Ref: Library<131>-Footnote-184576532
Ref: Library<131>-Footnote-194576598
Ref: Library<131>-Footnote-204576664
Ref: Library<131>-Footnote-214576730
Ref: Library<131>-Footnote-224576796
Ref: Library<131>-Footnote-234576862
Ref: Library<131>-Footnote-244576928
Ref: Library<131>-Footnote-254576994
Ref: Library<131>-Footnote-264577060
Ref: Library<131>-Footnote-274577126
Ref: Library<131>-Footnote-284577192
Ref: Library<131>-Footnote-294577258
Ref: Library<131>-Footnote-304577324
Ref: Library<131>-Footnote-314577390
Ref: Library<131>-Footnote-324577456
Ref: Library<131>-Footnote-334577522
Ref: Library<131>-Footnote-344577588
Ref: Library<131>-Footnote-354577654
Ref: Library<131>-Footnote-364577720
Ref: Library<131>-Footnote-374577786
Ref: Library<131>-Footnote-384577852
Ref: Library<131>-Footnote-394577918
Ref: Library<131>-Footnote-404577984
Ref: Library<131>-Footnote-414578050
Ref: Library<131>-Footnote-424578116
Ref: Library<131>-Footnote-434578182
Ref: Library<131>-Footnote-444578248
Ref: Library<131>-Footnote-454578314
Ref: Library<131>-Footnote-464578380
Ref: Library<131>-Footnote-474578446
Ref: Library<131>-Footnote-484578512
Ref: Library<131>-Footnote-494578578
Ref: Library<131>-Footnote-504578644
Ref: Library<131>-Footnote-514578710
Ref: Library<131>-Footnote-524578776
Ref: Library<131>-Footnote-534578842
Node: Documentation<47>4578908
Ref: whatsnew/changelog id6254579021
Ref: 1b394579021
Ref: Documentation<47>-Footnote-14579638
Ref: Documentation<47>-Footnote-24579703
Ref: Documentation<47>-Footnote-34579768
Node: Build<54>4579832
Ref: whatsnew/changelog id6264579941
Ref: 1b3b4579941
Ref: Build<54>-Footnote-14580467
Ref: Build<54>-Footnote-24580532
Ref: Build<54>-Footnote-34580597
Node: IDLE<34>4580662
Ref: whatsnew/changelog id6274580763
Ref: 1b3c4580763
Ref: IDLE<34>-Footnote-14581184
Ref: IDLE<34>-Footnote-24581249
Ref: IDLE<34>-Footnote-34581314
Node: C API<49>4581379
Ref: whatsnew/changelog id6284581462
Ref: 1b3d4581462
Ref: C API<49>-Footnote-14582227
Ref: C API<49>-Footnote-24582292
Node: Python 3 9 0 alpha 24582357
Ref: whatsnew/changelog python-3-9-0-alpha-24582481
Ref: 1b3e4582481
Node: Security<38>4582832
Ref: whatsnew/changelog id6294582932
Ref: 1b3f4582932
Ref: Security<38>-Footnote-14583805
Ref: Security<38>-Footnote-24583870
Ref: Security<38>-Footnote-34583935
Ref: Security<38>-Footnote-44584000
Node: Core and Builtins<130>4584065
Ref: whatsnew/changelog id6304584186
Ref: 1b404584186
Ref: Core and Builtins<130>-Footnote-14587895
Ref: Core and Builtins<130>-Footnote-24587960
Ref: Core and Builtins<130>-Footnote-34588025
Ref: Core and Builtins<130>-Footnote-44588090
Ref: Core and Builtins<130>-Footnote-54588155
Ref: Core and Builtins<130>-Footnote-64588220
Ref: Core and Builtins<130>-Footnote-74588285
Ref: Core and Builtins<130>-Footnote-84588350
Ref: Core and Builtins<130>-Footnote-94588415
Ref: Core and Builtins<130>-Footnote-104588480
Ref: Core and Builtins<130>-Footnote-114588546
Ref: Core and Builtins<130>-Footnote-124588612
Ref: Core and Builtins<130>-Footnote-134588678
Ref: Core and Builtins<130>-Footnote-144588744
Ref: Core and Builtins<130>-Footnote-154588810
Ref: Core and Builtins<130>-Footnote-164588876
Ref: Core and Builtins<130>-Footnote-174588942
Ref: Core and Builtins<130>-Footnote-184589008
Ref: Core and Builtins<130>-Footnote-194589074
Ref: Core and Builtins<130>-Footnote-204589140
Node: Library<132>4589206
Ref: whatsnew/changelog id6314589332
Ref: 1b414589332
Ref: Library<132>-Footnote-14597110
Ref: Library<132>-Footnote-24597175
Ref: Library<132>-Footnote-34597240
Ref: Library<132>-Footnote-44597305
Ref: Library<132>-Footnote-54597370
Ref: Library<132>-Footnote-64597435
Ref: Library<132>-Footnote-74597500
Ref: Library<132>-Footnote-84597565
Ref: Library<132>-Footnote-94597630
Ref: Library<132>-Footnote-104597695
Ref: Library<132>-Footnote-114597761
Ref: Library<132>-Footnote-124597827
Ref: Library<132>-Footnote-134597893
Ref: Library<132>-Footnote-144597959
Ref: Library<132>-Footnote-154598025
Ref: Library<132>-Footnote-164598091
Ref: Library<132>-Footnote-174598157
Ref: Library<132>-Footnote-184598223
Ref: Library<132>-Footnote-194598289
Ref: Library<132>-Footnote-204598355
Ref: Library<132>-Footnote-214598421
Ref: Library<132>-Footnote-224598487
Ref: Library<132>-Footnote-234598553
Ref: Library<132>-Footnote-244598619
Ref: Library<132>-Footnote-254598685
Ref: Library<132>-Footnote-264598751
Ref: Library<132>-Footnote-274598817
Ref: Library<132>-Footnote-284598883
Ref: Library<132>-Footnote-294598949
Ref: Library<132>-Footnote-304599015
Ref: Library<132>-Footnote-314599081
Ref: Library<132>-Footnote-324599147
Ref: Library<132>-Footnote-334599213
Ref: Library<132>-Footnote-344599279
Ref: Library<132>-Footnote-354599345
Ref: Library<132>-Footnote-364599411
Ref: Library<132>-Footnote-374599477
Ref: Library<132>-Footnote-384599543
Ref: Library<132>-Footnote-394599609
Ref: Library<132>-Footnote-404599675
Node: Documentation<48>4599741
Ref: whatsnew/changelog id6324599854
Ref: 1b424599854
Ref: Documentation<48>-Footnote-14600441
Ref: Documentation<48>-Footnote-24600506
Ref: Documentation<48>-Footnote-34600571
Node: Tests<50>4600636
Ref: whatsnew/changelog id6334600746
Ref: 1b434600746
Ref: Tests<50>-Footnote-14603326
Ref: Tests<50>-Footnote-24603391
Ref: Tests<50>-Footnote-34603456
Ref: Tests<50>-Footnote-44603521
Ref: Tests<50>-Footnote-54603586
Ref: Tests<50>-Footnote-64603651
Ref: Tests<50>-Footnote-74603716
Ref: Tests<50>-Footnote-84603781
Ref: Tests<50>-Footnote-94603846
Ref: Tests<50>-Footnote-104603911
Ref: Tests<50>-Footnote-114603977
Ref: Tests<50>-Footnote-124604043
Ref: Tests<50>-Footnote-134604109
Node: Build<55>4604175
Ref: whatsnew/changelog id6344604279
Ref: 1b474604279
Ref: Build<55>-Footnote-14604681
Ref: Build<55>-Footnote-24604746
Node: Windows<47>4604811
Ref: whatsnew/changelog id6354604915
Ref: 1b484604915
Ref: Windows<47>-Footnote-14605156
Ref: Windows<47>-Footnote-24605221
Node: macOS<38>4605286
Ref: whatsnew/changelog id6364605389
Ref: 1b494605389
Ref: macOS<38>-Footnote-14605697
Node: IDLE<35>4605762
Ref: whatsnew/changelog id6374605863
Ref: 1b4a4605863
Ref: IDLE<35>-Footnote-14606458
Ref: IDLE<35>-Footnote-24606523
Ref: IDLE<35>-Footnote-34606588
Ref: IDLE<35>-Footnote-44606653
Node: C API<50>4606718
Ref: whatsnew/changelog id6384606801
Ref: 1b4b4606801
Ref: C API<50>-Footnote-14607335
Ref: C API<50>-Footnote-24607400
Ref: C API<50>-Footnote-34607465
Node: Python 3 9 0 alpha 14607530
Ref: whatsnew/changelog python-3-9-0-alpha-14607653
Ref: 1b4c4607653
Node: Security<39>4608036
Ref: whatsnew/changelog id6394608136
Ref: 1b4d4608136
Ref: Security<39>-Footnote-14610459
Ref: Security<39>-Footnote-24610524
Ref: Security<39>-Footnote-34610589
Ref: Security<39>-Footnote-44610654
Ref: Security<39>-Footnote-54610719
Ref: Security<39>-Footnote-64610784
Ref: Security<39>-Footnote-74610849
Ref: Security<39>-Footnote-84610905
Ref: Security<39>-Footnote-94610970
Ref: Security<39>-Footnote-104611035
Ref: Security<39>-Footnote-114611101
Ref: Security<39>-Footnote-124611167
Ref: Security<39>-Footnote-134611233
Ref: Security<39>-Footnote-144611299
Ref: Security<39>-Footnote-154611365
Node: Core and Builtins<131>4611431
Ref: whatsnew/changelog id6404611552
Ref: 1b504611552
Ref: Core and Builtins<131>-Footnote-14627094
Ref: Core and Builtins<131>-Footnote-24627159
Ref: Core and Builtins<131>-Footnote-34627224
Ref: Core and Builtins<131>-Footnote-44627289
Ref: Core and Builtins<131>-Footnote-54627354
Ref: Core and Builtins<131>-Footnote-64627419
Ref: Core and Builtins<131>-Footnote-74627484
Ref: Core and Builtins<131>-Footnote-84627549
Ref: Core and Builtins<131>-Footnote-94627614
Ref: Core and Builtins<131>-Footnote-104627679
Ref: Core and Builtins<131>-Footnote-114627745
Ref: Core and Builtins<131>-Footnote-124627811
Ref: Core and Builtins<131>-Footnote-134627877
Ref: Core and Builtins<131>-Footnote-144627943
Ref: Core and Builtins<131>-Footnote-154628009
Ref: Core and Builtins<131>-Footnote-164628075
Ref: Core and Builtins<131>-Footnote-174628141
Ref: Core and Builtins<131>-Footnote-184628207
Ref: Core and Builtins<131>-Footnote-194628273
Ref: Core and Builtins<131>-Footnote-204628339
Ref: Core and Builtins<131>-Footnote-214628382
Ref: Core and Builtins<131>-Footnote-224628448
Ref: Core and Builtins<131>-Footnote-234628514
Ref: Core and Builtins<131>-Footnote-244628580
Ref: Core and Builtins<131>-Footnote-254628646
Ref: Core and Builtins<131>-Footnote-264628712
Ref: Core and Builtins<131>-Footnote-274628778
Ref: Core and Builtins<131>-Footnote-284628844
Ref: Core and Builtins<131>-Footnote-294628910
Ref: Core and Builtins<131>-Footnote-304628976
Ref: Core and Builtins<131>-Footnote-314629042
Ref: Core and Builtins<131>-Footnote-324629108
Ref: Core and Builtins<131>-Footnote-334629174
Ref: Core and Builtins<131>-Footnote-344629240
Ref: Core and Builtins<131>-Footnote-354629306
Ref: Core and Builtins<131>-Footnote-364629372
Ref: Core and Builtins<131>-Footnote-374629438
Ref: Core and Builtins<131>-Footnote-384629504
Ref: Core and Builtins<131>-Footnote-394629570
Ref: Core and Builtins<131>-Footnote-404629636
Ref: Core and Builtins<131>-Footnote-414629701
Ref: Core and Builtins<131>-Footnote-424629767
Ref: Core and Builtins<131>-Footnote-434629833
Ref: Core and Builtins<131>-Footnote-444629899
Ref: Core and Builtins<131>-Footnote-454629965
Ref: Core and Builtins<131>-Footnote-464630031
Ref: Core and Builtins<131>-Footnote-474630097
Ref: Core and Builtins<131>-Footnote-484630163
Ref: Core and Builtins<131>-Footnote-494630229
Ref: Core and Builtins<131>-Footnote-504630295
Ref: Core and Builtins<131>-Footnote-514630361
Ref: Core and Builtins<131>-Footnote-524630427
Ref: Core and Builtins<131>-Footnote-534630493
Ref: Core and Builtins<131>-Footnote-544630536
Ref: Core and Builtins<131>-Footnote-554630602
Ref: Core and Builtins<131>-Footnote-564630668
Ref: Core and Builtins<131>-Footnote-574630734
Ref: Core and Builtins<131>-Footnote-584630800
Ref: Core and Builtins<131>-Footnote-594630866
Ref: Core and Builtins<131>-Footnote-604630932
Ref: Core and Builtins<131>-Footnote-614630998
Ref: Core and Builtins<131>-Footnote-624631064
Ref: Core and Builtins<131>-Footnote-634631130
Ref: Core and Builtins<131>-Footnote-644631196
Ref: Core and Builtins<131>-Footnote-654631262
Ref: Core and Builtins<131>-Footnote-664631328
Ref: Core and Builtins<131>-Footnote-674631394
Ref: Core and Builtins<131>-Footnote-684631460
Ref: Core and Builtins<131>-Footnote-694631526
Ref: Core and Builtins<131>-Footnote-704631592
Ref: Core and Builtins<131>-Footnote-714631658
Ref: Core and Builtins<131>-Footnote-724631724
Ref: Core and Builtins<131>-Footnote-734631790
Ref: Core and Builtins<131>-Footnote-744631856
Ref: Core and Builtins<131>-Footnote-754631922
Ref: Core and Builtins<131>-Footnote-764631988
Ref: Core and Builtins<131>-Footnote-774632054
Ref: Core and Builtins<131>-Footnote-784632120
Ref: Core and Builtins<131>-Footnote-794632186
Ref: Core and Builtins<131>-Footnote-804632252
Ref: Core and Builtins<131>-Footnote-814632318
Ref: Core and Builtins<131>-Footnote-824632384
Ref: Core and Builtins<131>-Footnote-834632450
Ref: Core and Builtins<131>-Footnote-844632516
Ref: Core and Builtins<131>-Footnote-854632582
Ref: Core and Builtins<131>-Footnote-864632648
Ref: Core and Builtins<131>-Footnote-874632714
Ref: Core and Builtins<131>-Footnote-884632780
Ref: Core and Builtins<131>-Footnote-894632846
Ref: Core and Builtins<131>-Footnote-904632912
Ref: Core and Builtins<131>-Footnote-914632978
Ref: Core and Builtins<131>-Footnote-924633044
Ref: Core and Builtins<131>-Footnote-934633110
Ref: Core and Builtins<131>-Footnote-944633176
Node: Library<133>4633242
Ref: whatsnew/changelog id6414633368
Ref: 1b554633368
Ref: Library<133>-Footnote-14672856
Ref: Library<133>-Footnote-24672921
Ref: Library<133>-Footnote-34672986
Ref: Library<133>-Footnote-44673051
Ref: Library<133>-Footnote-54673116
Ref: Library<133>-Footnote-64673181
Ref: Library<133>-Footnote-74673246
Ref: Library<133>-Footnote-84673311
Ref: Library<133>-Footnote-94673376
Ref: Library<133>-Footnote-104673441
Ref: Library<133>-Footnote-114673507
Ref: Library<133>-Footnote-124673573
Ref: Library<133>-Footnote-134673639
Ref: Library<133>-Footnote-144673705
Ref: Library<133>-Footnote-154673771
Ref: Library<133>-Footnote-164673837
Ref: Library<133>-Footnote-174673903
Ref: Library<133>-Footnote-184673969
Ref: Library<133>-Footnote-194674035
Ref: Library<133>-Footnote-204674101
Ref: Library<133>-Footnote-214674167
Ref: Library<133>-Footnote-224674233
Ref: Library<133>-Footnote-234674299
Ref: Library<133>-Footnote-244674365
Ref: Library<133>-Footnote-254674431
Ref: Library<133>-Footnote-264674497
Ref: Library<133>-Footnote-274674563
Ref: Library<133>-Footnote-284674629
Ref: Library<133>-Footnote-294674695
Ref: Library<133>-Footnote-304674761
Ref: Library<133>-Footnote-314674827
Ref: Library<133>-Footnote-324674893
Ref: Library<133>-Footnote-334674959
Ref: Library<133>-Footnote-344675025
Ref: Library<133>-Footnote-354675091
Ref: Library<133>-Footnote-364675157
Ref: Library<133>-Footnote-374675223
Ref: Library<133>-Footnote-384675289
Ref: Library<133>-Footnote-394675355
Ref: Library<133>-Footnote-404675421
Ref: Library<133>-Footnote-414675487
Ref: Library<133>-Footnote-424675553
Ref: Library<133>-Footnote-434675619
Ref: Library<133>-Footnote-444675685
Ref: Library<133>-Footnote-454675751
Ref: Library<133>-Footnote-464675817
Ref: Library<133>-Footnote-474675883
Ref: Library<133>-Footnote-484675949
Ref: Library<133>-Footnote-494676015
Ref: Library<133>-Footnote-504676081
Ref: Library<133>-Footnote-514676147
Ref: Library<133>-Footnote-524676213
Ref: Library<133>-Footnote-534676279
Ref: Library<133>-Footnote-544676345
Ref: Library<133>-Footnote-554676411
Ref: Library<133>-Footnote-564676477
Ref: Library<133>-Footnote-574676543
Ref: Library<133>-Footnote-584676609
Ref: Library<133>-Footnote-594676675
Ref: Library<133>-Footnote-604676741
Ref: Library<133>-Footnote-614676807
Ref: Library<133>-Footnote-624676873
Ref: Library<133>-Footnote-634676939
Ref: Library<133>-Footnote-644677004
Ref: Library<133>-Footnote-654677070
Ref: Library<133>-Footnote-664677136
Ref: Library<133>-Footnote-674677202
Ref: Library<133>-Footnote-684677268
Ref: Library<133>-Footnote-694677334
Ref: Library<133>-Footnote-704677400
Ref: Library<133>-Footnote-714677466
Ref: Library<133>-Footnote-724677532
Ref: Library<133>-Footnote-734677598
Ref: Library<133>-Footnote-744677664
Ref: Library<133>-Footnote-754677730
Ref: Library<133>-Footnote-764677796
Ref: Library<133>-Footnote-774677904
Ref: Library<133>-Footnote-784677970
Ref: Library<133>-Footnote-794678036
Ref: Library<133>-Footnote-804678102
Ref: Library<133>-Footnote-814678168
Ref: Library<133>-Footnote-824678234
Ref: Library<133>-Footnote-834678300
Ref: Library<133>-Footnote-844678366
Ref: Library<133>-Footnote-854678432
Ref: Library<133>-Footnote-864678498
Ref: Library<133>-Footnote-874678564
Ref: Library<133>-Footnote-884678630
Ref: Library<133>-Footnote-894678696
Ref: Library<133>-Footnote-904678762
Ref: Library<133>-Footnote-914678828
Ref: Library<133>-Footnote-924678894
Ref: Library<133>-Footnote-934678960
Ref: Library<133>-Footnote-944679026
Ref: Library<133>-Footnote-954679092
Ref: Library<133>-Footnote-964679158
Ref: Library<133>-Footnote-974679224
Ref: Library<133>-Footnote-984679290
Ref: Library<133>-Footnote-994679356
Ref: Library<133>-Footnote-1004679422
Ref: Library<133>-Footnote-1014679489
Ref: Library<133>-Footnote-1024679556
Ref: Library<133>-Footnote-1034679623
Ref: Library<133>-Footnote-1044679690
Ref: Library<133>-Footnote-1054679757
Ref: Library<133>-Footnote-1064679824
Ref: Library<133>-Footnote-1074679891
Ref: Library<133>-Footnote-1084679957
Ref: Library<133>-Footnote-1094680024
Ref: Library<133>-Footnote-1104680091
Ref: Library<133>-Footnote-1114680158
Ref: Library<133>-Footnote-1124680225
Ref: Library<133>-Footnote-1134680292
Ref: Library<133>-Footnote-1144680359
Ref: Library<133>-Footnote-1154680426
Ref: Library<133>-Footnote-1164680493
Ref: Library<133>-Footnote-1174680560
Ref: Library<133>-Footnote-1184680627
Ref: Library<133>-Footnote-1194680694
Ref: Library<133>-Footnote-1204680761
Ref: Library<133>-Footnote-1214680828
Ref: Library<133>-Footnote-1224680895
Ref: Library<133>-Footnote-1234680962
Ref: Library<133>-Footnote-1244681029
Ref: Library<133>-Footnote-1254681096
Ref: Library<133>-Footnote-1264681163
Ref: Library<133>-Footnote-1274681230
Ref: Library<133>-Footnote-1284681297
Ref: Library<133>-Footnote-1294681364
Ref: Library<133>-Footnote-1304681431
Ref: Library<133>-Footnote-1314681498
Ref: Library<133>-Footnote-1324681565
Ref: Library<133>-Footnote-1334681632
Ref: Library<133>-Footnote-1344681699
Ref: Library<133>-Footnote-1354681766
Ref: Library<133>-Footnote-1364681833
Ref: Library<133>-Footnote-1374681910
Ref: Library<133>-Footnote-1384681977
Ref: Library<133>-Footnote-1394682044
Ref: Library<133>-Footnote-1404682111
Ref: Library<133>-Footnote-1414682178
Ref: Library<133>-Footnote-1424682245
Ref: Library<133>-Footnote-1434682312
Ref: Library<133>-Footnote-1444682379
Ref: Library<133>-Footnote-1454682446
Ref: Library<133>-Footnote-1464682513
Ref: Library<133>-Footnote-1474682580
Ref: Library<133>-Footnote-1484682647
Ref: Library<133>-Footnote-1494682714
Ref: Library<133>-Footnote-1504682781
Ref: Library<133>-Footnote-1514682848
Ref: Library<133>-Footnote-1524682915
Ref: Library<133>-Footnote-1534682982
Ref: Library<133>-Footnote-1544683049
Ref: Library<133>-Footnote-1554683116
Ref: Library<133>-Footnote-1564683183
Ref: Library<133>-Footnote-1574683250
Ref: Library<133>-Footnote-1584683317
Ref: Library<133>-Footnote-1594683384
Ref: Library<133>-Footnote-1604683451
Ref: Library<133>-Footnote-1614683518
Ref: Library<133>-Footnote-1624683585
Ref: Library<133>-Footnote-1634683652
Ref: Library<133>-Footnote-1644683719
Ref: Library<133>-Footnote-1654683786
Ref: Library<133>-Footnote-1664683853
Ref: Library<133>-Footnote-1674683920
Ref: Library<133>-Footnote-1684683987
Ref: Library<133>-Footnote-1694684054
Ref: Library<133>-Footnote-1704684121
Ref: Library<133>-Footnote-1714684188
Ref: Library<133>-Footnote-1724684255
Ref: Library<133>-Footnote-1734684299
Ref: Library<133>-Footnote-1744684366
Ref: Library<133>-Footnote-1754684433
Ref: Library<133>-Footnote-1764684500
Ref: Library<133>-Footnote-1774684567
Ref: Library<133>-Footnote-1784684634
Ref: Library<133>-Footnote-1794684701
Ref: Library<133>-Footnote-1804684768
Ref: Library<133>-Footnote-1814684835
Ref: Library<133>-Footnote-1824684902
Ref: Library<133>-Footnote-1834684969
Ref: Library<133>-Footnote-1844685036
Ref: Library<133>-Footnote-1854685103
Ref: Library<133>-Footnote-1864685170
Ref: Library<133>-Footnote-1874685237
Ref: Library<133>-Footnote-1884685304
Ref: Library<133>-Footnote-1894685371
Ref: Library<133>-Footnote-1904685438
Ref: Library<133>-Footnote-1914685505
Ref: Library<133>-Footnote-1924685572
Ref: Library<133>-Footnote-1934685639
Ref: Library<133>-Footnote-1944685706
Ref: Library<133>-Footnote-1954685773
Ref: Library<133>-Footnote-1964685840
Ref: Library<133>-Footnote-1974685907
Ref: Library<133>-Footnote-1984685974
Ref: Library<133>-Footnote-1994686041
Ref: Library<133>-Footnote-2004686108
Ref: Library<133>-Footnote-2014686175
Ref: Library<133>-Footnote-2024686242
Ref: Library<133>-Footnote-2034686309
Ref: Library<133>-Footnote-2044686376
Ref: Library<133>-Footnote-2054686443
Ref: Library<133>-Footnote-2064686510
Ref: Library<133>-Footnote-2074686577
Ref: Library<133>-Footnote-2084686644
Ref: Library<133>-Footnote-2094686711
Ref: Library<133>-Footnote-2104686778
Ref: Library<133>-Footnote-2114686845
Ref: Library<133>-Footnote-2124686912
Ref: Library<133>-Footnote-2134686979
Ref: Library<133>-Footnote-2144687046
Ref: Library<133>-Footnote-2154687113
Ref: Library<133>-Footnote-2164687180
Ref: Library<133>-Footnote-2174687247
Ref: Library<133>-Footnote-2184687314
Ref: Library<133>-Footnote-2194687381
Ref: Library<133>-Footnote-2204687448
Ref: Library<133>-Footnote-2214687515
Ref: Library<133>-Footnote-2224687582
Ref: Library<133>-Footnote-2234687649
Ref: Library<133>-Footnote-2244687716
Ref: Library<133>-Footnote-2254687783
Ref: Library<133>-Footnote-2264687850
Ref: Library<133>-Footnote-2274687917
Ref: Library<133>-Footnote-2284687984
Ref: Library<133>-Footnote-2294688051
Ref: Library<133>-Footnote-2304688118
Ref: Library<133>-Footnote-2314688185
Ref: Library<133>-Footnote-2324688252
Ref: Library<133>-Footnote-2334688319
Ref: Library<133>-Footnote-2344688386
Ref: Library<133>-Footnote-2354688453
Ref: Library<133>-Footnote-2364688520
Ref: Library<133>-Footnote-2374688587
Ref: Library<133>-Footnote-2384688654
Ref: Library<133>-Footnote-2394688721
Ref: Library<133>-Footnote-2404688787
Ref: Library<133>-Footnote-2414688854
Ref: Library<133>-Footnote-2424688921
Ref: Library<133>-Footnote-2434688988
Ref: Library<133>-Footnote-2444689055
Ref: Library<133>-Footnote-2454689122
Ref: Library<133>-Footnote-2464689189
Ref: Library<133>-Footnote-2474689256
Ref: Library<133>-Footnote-2484689323
Ref: Library<133>-Footnote-2494689390
Ref: Library<133>-Footnote-2504689457
Ref: Library<133>-Footnote-2514689524
Ref: Library<133>-Footnote-2524689591
Ref: Library<133>-Footnote-2534689658
Node: Documentation<49>4689724
Ref: whatsnew/changelog id6424689837
Ref: 1b624689837
Ref: Documentation<49>-Footnote-14694308
Ref: Documentation<49>-Footnote-24694373
Ref: Documentation<49>-Footnote-34694438
Ref: Documentation<49>-Footnote-44694503
Ref: Documentation<49>-Footnote-54694568
Ref: Documentation<49>-Footnote-64694633
Ref: Documentation<49>-Footnote-74694698
Ref: Documentation<49>-Footnote-84694763
Ref: Documentation<49>-Footnote-94694828
Ref: Documentation<49>-Footnote-104694893
Ref: Documentation<49>-Footnote-114694959
Ref: Documentation<49>-Footnote-124695025
Ref: Documentation<49>-Footnote-134695091
Ref: Documentation<49>-Footnote-144695157
Ref: Documentation<49>-Footnote-154695223
Ref: Documentation<49>-Footnote-164695289
Ref: Documentation<49>-Footnote-174695355
Ref: Documentation<49>-Footnote-184695421
Ref: Documentation<49>-Footnote-194695487
Ref: Documentation<49>-Footnote-204695553
Ref: Documentation<49>-Footnote-214695619
Ref: Documentation<49>-Footnote-224695685
Ref: Documentation<49>-Footnote-234695751
Ref: Documentation<49>-Footnote-244695817
Ref: Documentation<49>-Footnote-254695883
Ref: Documentation<49>-Footnote-264695949
Ref: Documentation<49>-Footnote-274696015
Ref: Documentation<49>-Footnote-284696081
Ref: Documentation<49>-Footnote-294696147
Ref: Documentation<49>-Footnote-304696213
Ref: Documentation<49>-Footnote-314696279
Ref: Documentation<49>-Footnote-324696345
Ref: Documentation<49>-Footnote-334696411
Ref: Documentation<49>-Footnote-344696477
Ref: Documentation<49>-Footnote-354696543
Node: Tests<51>4696609
Ref: whatsnew/changelog id6434696719
Ref: 1b644696719
Ref: Tests<51>-Footnote-14704856
Ref: Tests<51>-Footnote-24704921
Ref: Tests<51>-Footnote-34704986
Ref: Tests<51>-Footnote-44705051
Ref: Tests<51>-Footnote-54705116
Ref: Tests<51>-Footnote-64705181
Ref: Tests<51>-Footnote-74705246
Ref: Tests<51>-Footnote-84705311
Ref: Tests<51>-Footnote-94705376
Ref: Tests<51>-Footnote-104705441
Ref: Tests<51>-Footnote-114705507
Ref: Tests<51>-Footnote-124705573
Ref: Tests<51>-Footnote-134705639
Ref: Tests<51>-Footnote-144705705
Ref: Tests<51>-Footnote-154705771
Ref: Tests<51>-Footnote-164705837
Ref: Tests<51>-Footnote-174705903
Ref: Tests<51>-Footnote-184705969
Ref: Tests<51>-Footnote-194706035
Ref: Tests<51>-Footnote-204706101
Ref: Tests<51>-Footnote-214706167
Ref: Tests<51>-Footnote-224706233
Ref: Tests<51>-Footnote-234706299
Ref: Tests<51>-Footnote-244706365
Ref: Tests<51>-Footnote-254706431
Ref: Tests<51>-Footnote-264706497
Ref: Tests<51>-Footnote-274706563
Ref: Tests<51>-Footnote-284706629
Ref: Tests<51>-Footnote-294706695
Ref: Tests<51>-Footnote-304706761
Ref: Tests<51>-Footnote-314706827
Ref: Tests<51>-Footnote-324706893
Ref: Tests<51>-Footnote-334706959
Ref: Tests<51>-Footnote-344707025
Ref: Tests<51>-Footnote-354707091
Ref: Tests<51>-Footnote-364707157
Ref: Tests<51>-Footnote-374707223
Ref: Tests<51>-Footnote-384707289
Ref: Tests<51>-Footnote-394707355
Ref: Tests<51>-Footnote-404707421
Ref: Tests<51>-Footnote-414707487
Ref: Tests<51>-Footnote-424707553
Ref: Tests<51>-Footnote-434707619
Ref: Tests<51>-Footnote-444707685
Ref: Tests<51>-Footnote-454707751
Ref: Tests<51>-Footnote-464707817
Ref: Tests<51>-Footnote-474707883
Ref: Tests<51>-Footnote-484707949
Node: Build<56>4708015
Ref: whatsnew/changelog id6444708119
Ref: 1b6a4708119
Ref: Build<56>-Footnote-14711958
Ref: Build<56>-Footnote-24712023
Ref: Build<56>-Footnote-34712088
Ref: Build<56>-Footnote-44712153
Ref: Build<56>-Footnote-54712218
Ref: Build<56>-Footnote-64712283
Ref: Build<56>-Footnote-74712348
Ref: Build<56>-Footnote-84712413
Ref: Build<56>-Footnote-94712478
Ref: Build<56>-Footnote-104712543
Ref: Build<56>-Footnote-114712609
Ref: Build<56>-Footnote-124712675
Ref: Build<56>-Footnote-134712741
Ref: Build<56>-Footnote-144712807
Ref: Build<56>-Footnote-154712873
Ref: Build<56>-Footnote-164712939
Node: Windows<48>4713005
Ref: whatsnew/changelog id6454713109
Ref: 1b6c4713109
Ref: Windows<48>-Footnote-14718017
Ref: Windows<48>-Footnote-24718082
Ref: Windows<48>-Footnote-34718147
Ref: Windows<48>-Footnote-44718212
Ref: Windows<48>-Footnote-54718277
Ref: Windows<48>-Footnote-64718342
Ref: Windows<48>-Footnote-74718407
Ref: Windows<48>-Footnote-84718472
Ref: Windows<48>-Footnote-94718537
Ref: Windows<48>-Footnote-104718602
Ref: Windows<48>-Footnote-114718668
Ref: Windows<48>-Footnote-124718734
Ref: Windows<48>-Footnote-134718800
Ref: Windows<48>-Footnote-144718866
Ref: Windows<48>-Footnote-154718932
Ref: Windows<48>-Footnote-164718998
Ref: Windows<48>-Footnote-174719064
Ref: Windows<48>-Footnote-184719130
Ref: Windows<48>-Footnote-194719196
Ref: Windows<48>-Footnote-204719262
Ref: Windows<48>-Footnote-214719328
Ref: Windows<48>-Footnote-224719394
Ref: Windows<48>-Footnote-234719460
Ref: Windows<48>-Footnote-244719525
Ref: Windows<48>-Footnote-254719590
Ref: Windows<48>-Footnote-264719656
Ref: Windows<48>-Footnote-274719722
Ref: Windows<48>-Footnote-284719788
Ref: Windows<48>-Footnote-294719854
Ref: Windows<48>-Footnote-304719920
Ref: Windows<48>-Footnote-314719986
Ref: Windows<48>-Footnote-324720052
Ref: Windows<48>-Footnote-334720118
Ref: Windows<48>-Footnote-344720184
Ref: Windows<48>-Footnote-354720250
Ref: Windows<48>-Footnote-364720316
Ref: Windows<48>-Footnote-374720382
Ref: Windows<48>-Footnote-384720448
Ref: Windows<48>-Footnote-394720514
Ref: Windows<48>-Footnote-404720580
Ref: Windows<48>-Footnote-414720646
Ref: Windows<48>-Footnote-424720712
Node: macOS<39>4720778
Ref: whatsnew/changelog id6464720881
Ref: 1b6f4720881
Ref: macOS<39>-Footnote-14721714
Ref: macOS<39>-Footnote-24721779
Ref: macOS<39>-Footnote-34721844
Ref: macOS<39>-Footnote-44721909
Ref: macOS<39>-Footnote-54721974
Ref: macOS<39>-Footnote-64722039
Node: IDLE<36>4722104
Ref: whatsnew/changelog id6474722211
Ref: 1b704722211
Ref: IDLE<36>-Footnote-14726950
Ref: IDLE<36>-Footnote-24727015
Ref: IDLE<36>-Footnote-34727079
Ref: IDLE<36>-Footnote-44727144
Ref: IDLE<36>-Footnote-54727209
Ref: IDLE<36>-Footnote-64727274
Ref: IDLE<36>-Footnote-74727339
Ref: IDLE<36>-Footnote-84727404
Ref: IDLE<36>-Footnote-94727469
Ref: IDLE<36>-Footnote-104727534
Ref: IDLE<36>-Footnote-114727600
Ref: IDLE<36>-Footnote-124727666
Ref: IDLE<36>-Footnote-134727732
Ref: IDLE<36>-Footnote-144727798
Ref: IDLE<36>-Footnote-154727864
Ref: IDLE<36>-Footnote-164727930
Ref: IDLE<36>-Footnote-174727996
Ref: IDLE<36>-Footnote-184728062
Ref: IDLE<36>-Footnote-194728128
Ref: IDLE<36>-Footnote-204728194
Ref: IDLE<36>-Footnote-214728260
Ref: IDLE<36>-Footnote-224728326
Ref: IDLE<36>-Footnote-234728392
Ref: IDLE<36>-Footnote-244728458
Ref: IDLE<36>-Footnote-254728524
Ref: IDLE<36>-Footnote-264728590
Ref: IDLE<36>-Footnote-274728656
Ref: IDLE<36>-Footnote-284728722
Ref: IDLE<36>-Footnote-294728788
Ref: IDLE<36>-Footnote-304728853
Node: Tools/Demos<26>4728919
Ref: whatsnew/changelog id6484729026
Ref: 1b714729026
Ref: Tools/Demos<26>-Footnote-14730027
Ref: Tools/Demos<26>-Footnote-24730092
Ref: Tools/Demos<26>-Footnote-34730157
Ref: Tools/Demos<26>-Footnote-44730222
Ref: Tools/Demos<26>-Footnote-54730287
Ref: Tools/Demos<26>-Footnote-64730352
Ref: Tools/Demos<26>-Footnote-74730417
Ref: Tools/Demos<26>-Footnote-84730482
Node: C API<51>4730547
Ref: whatsnew/changelog id6494730637
Ref: 1b734730637
Ref: C API<51>-Footnote-14736032
Ref: C API<51>-Footnote-24736097
Ref: C API<51>-Footnote-34736162
Ref: C API<51>-Footnote-44736227
Ref: C API<51>-Footnote-54736292
Ref: C API<51>-Footnote-64736357
Ref: C API<51>-Footnote-74736422
Ref: C API<51>-Footnote-84736487
Ref: C API<51>-Footnote-94736552
Ref: C API<51>-Footnote-104736617
Ref: C API<51>-Footnote-114736683
Ref: C API<51>-Footnote-124736749
Ref: C API<51>-Footnote-134736815
Ref: C API<51>-Footnote-144736881
Ref: C API<51>-Footnote-154736924
Ref: C API<51>-Footnote-164736990
Ref: C API<51>-Footnote-174737056
Ref: C API<51>-Footnote-184737122
Ref: C API<51>-Footnote-194737188
Ref: C API<51>-Footnote-204737254
Ref: C API<51>-Footnote-214737320
Ref: C API<51>-Footnote-224737386
Ref: C API<51>-Footnote-234737452
Ref: C API<51>-Footnote-244737518
Ref: C API<51>-Footnote-254737584
Ref: C API<51>-Footnote-264737650
Ref: C API<51>-Footnote-274737716
Ref: C API<51>-Footnote-284737782
Ref: C API<51>-Footnote-294737848
Ref: C API<51>-Footnote-304737914
Ref: C API<51>-Footnote-314737980
Ref: C API<51>-Footnote-324738046
Ref: C API<51>-Footnote-334738112
Ref: C API<51>-Footnote-344738178
Node: Python 3 8 0 beta 14738244
Ref: whatsnew/changelog python-3-8-0-beta-14738367
Ref: 1b774738367
Node: Security<40>4738748
Ref: whatsnew/changelog id6504738847
Ref: 1b784738847
Ref: Security<40>-Footnote-14739441
Ref: Security<40>-Footnote-24739506
Ref: Security<40>-Footnote-34739561
Ref: Security<40>-Footnote-44739626
Node: Core and Builtins<132>4739691
Ref: whatsnew/changelog id6514739811
Ref: 1b794739811
Ref: Core and Builtins<132>-Footnote-14747871
Ref: Core and Builtins<132>-Footnote-24747936
Ref: Core and Builtins<132>-Footnote-34748001
Ref: Core and Builtins<132>-Footnote-44748066
Ref: Core and Builtins<132>-Footnote-54748131
Ref: Core and Builtins<132>-Footnote-64748196
Ref: Core and Builtins<132>-Footnote-74748261
Ref: Core and Builtins<132>-Footnote-84748326
Ref: Core and Builtins<132>-Footnote-94748391
Ref: Core and Builtins<132>-Footnote-104748456
Ref: Core and Builtins<132>-Footnote-114748522
Ref: Core and Builtins<132>-Footnote-124748588
Ref: Core and Builtins<132>-Footnote-134748654
Ref: Core and Builtins<132>-Footnote-144748720
Ref: Core and Builtins<132>-Footnote-154748786
Ref: Core and Builtins<132>-Footnote-164748852
Ref: Core and Builtins<132>-Footnote-174748918
Ref: Core and Builtins<132>-Footnote-184748984
Ref: Core and Builtins<132>-Footnote-194749049
Ref: Core and Builtins<132>-Footnote-204749115
Ref: Core and Builtins<132>-Footnote-214749181
Ref: Core and Builtins<132>-Footnote-224749247
Ref: Core and Builtins<132>-Footnote-234749312
Ref: Core and Builtins<132>-Footnote-244749378
Ref: Core and Builtins<132>-Footnote-254749444
Ref: Core and Builtins<132>-Footnote-264749510
Ref: Core and Builtins<132>-Footnote-274749576
Ref: Core and Builtins<132>-Footnote-284749642
Ref: Core and Builtins<132>-Footnote-294749708
Ref: Core and Builtins<132>-Footnote-304749774
Ref: Core and Builtins<132>-Footnote-314749840
Ref: Core and Builtins<132>-Footnote-324749906
Ref: Core and Builtins<132>-Footnote-334749972
Ref: Core and Builtins<132>-Footnote-344750038
Ref: Core and Builtins<132>-Footnote-354750104
Ref: Core and Builtins<132>-Footnote-364750170
Ref: Core and Builtins<132>-Footnote-374750236
Ref: Core and Builtins<132>-Footnote-384750302
Ref: Core and Builtins<132>-Footnote-394750368
Ref: Core and Builtins<132>-Footnote-404750434
Ref: Core and Builtins<132>-Footnote-414750500
Ref: Core and Builtins<132>-Footnote-424750566
Ref: Core and Builtins<132>-Footnote-434750632
Ref: Core and Builtins<132>-Footnote-444750698
Node: Library<134>4750764
Ref: whatsnew/changelog id6524750889
Ref: 1b7c4750889
Ref: Library<134>-Footnote-14769120
Ref: Library<134>-Footnote-24769185
Ref: Library<134>-Footnote-34769250
Ref: Library<134>-Footnote-44769315
Ref: Library<134>-Footnote-54769380
Ref: Library<134>-Footnote-64769445
Ref: Library<134>-Footnote-74769510
Ref: Library<134>-Footnote-84769575
Ref: Library<134>-Footnote-94769640
Ref: Library<134>-Footnote-104769705
Ref: Library<134>-Footnote-114769771
Ref: Library<134>-Footnote-124769837
Ref: Library<134>-Footnote-134769903
Ref: Library<134>-Footnote-144769969
Ref: Library<134>-Footnote-154770035
Ref: Library<134>-Footnote-164770101
Ref: Library<134>-Footnote-174770167
Ref: Library<134>-Footnote-184770233
Ref: Library<134>-Footnote-194770299
Ref: Library<134>-Footnote-204770365
Ref: Library<134>-Footnote-214770431
Ref: Library<134>-Footnote-224770497
Ref: Library<134>-Footnote-234770563
Ref: Library<134>-Footnote-244770629
Ref: Library<134>-Footnote-254770697
Ref: Library<134>-Footnote-264770763
Ref: Library<134>-Footnote-274770829
Ref: Library<134>-Footnote-284770895
Ref: Library<134>-Footnote-294770961
Ref: Library<134>-Footnote-304771027
Ref: Library<134>-Footnote-314771093
Ref: Library<134>-Footnote-324771159
Ref: Library<134>-Footnote-334771225
Ref: Library<134>-Footnote-344771291
Ref: Library<134>-Footnote-354771357
Ref: Library<134>-Footnote-364771423
Ref: Library<134>-Footnote-374771489
Ref: Library<134>-Footnote-384771555
Ref: Library<134>-Footnote-394771621
Ref: Library<134>-Footnote-404771687
Ref: Library<134>-Footnote-414771753
Ref: Library<134>-Footnote-424771819
Ref: Library<134>-Footnote-434771885
Ref: Library<134>-Footnote-444771951
Ref: Library<134>-Footnote-454772017
Ref: Library<134>-Footnote-464772083
Ref: Library<134>-Footnote-474772149
Ref: Library<134>-Footnote-484772215
Ref: Library<134>-Footnote-494772281
Ref: Library<134>-Footnote-504772347
Ref: Library<134>-Footnote-514772413
Ref: Library<134>-Footnote-524772479
Ref: Library<134>-Footnote-534772545
Ref: Library<134>-Footnote-544772611
Ref: Library<134>-Footnote-554772677
Ref: Library<134>-Footnote-564772743
Ref: Library<134>-Footnote-574772809
Ref: Library<134>-Footnote-584772875
Ref: Library<134>-Footnote-594772941
Ref: Library<134>-Footnote-604773007
Ref: Library<134>-Footnote-614773073
Ref: Library<134>-Footnote-624773139
Ref: Library<134>-Footnote-634773205
Ref: Library<134>-Footnote-644773271
Ref: Library<134>-Footnote-654773337
Ref: Library<134>-Footnote-664773403
Ref: Library<134>-Footnote-674773469
Ref: Library<134>-Footnote-684773535
Ref: Library<134>-Footnote-694773600
Ref: Library<134>-Footnote-704773666
Ref: Library<134>-Footnote-714773731
Ref: Library<134>-Footnote-724773797
Ref: Library<134>-Footnote-734773863
Ref: Library<134>-Footnote-744773929
Ref: Library<134>-Footnote-754773995
Ref: Library<134>-Footnote-764774061
Ref: Library<134>-Footnote-774774127
Ref: Library<134>-Footnote-784774193
Ref: Library<134>-Footnote-794774259
Ref: Library<134>-Footnote-804774325
Ref: Library<134>-Footnote-814774391
Ref: Library<134>-Footnote-824774457
Ref: Library<134>-Footnote-834774523
Ref: Library<134>-Footnote-844774589
Ref: Library<134>-Footnote-854774655
Ref: Library<134>-Footnote-864774721
Ref: Library<134>-Footnote-874774787
Ref: Library<134>-Footnote-884774853
Ref: Library<134>-Footnote-894774919
Ref: Library<134>-Footnote-904774985
Ref: Library<134>-Footnote-914775051
Ref: Library<134>-Footnote-924775117
Ref: Library<134>-Footnote-934775183
Ref: Library<134>-Footnote-944775249
Ref: Library<134>-Footnote-954775315
Ref: Library<134>-Footnote-964775381
Ref: Library<134>-Footnote-974775447
Ref: Library<134>-Footnote-984775513
Ref: Library<134>-Footnote-994775579
Ref: Library<134>-Footnote-1004775645
Ref: Library<134>-Footnote-1014775712
Ref: Library<134>-Footnote-1024775779
Ref: Library<134>-Footnote-1034775846
Ref: Library<134>-Footnote-1044775913
Ref: Library<134>-Footnote-1054775980
Ref: Library<134>-Footnote-1064776047
Ref: Library<134>-Footnote-1074776114
Node: Documentation<50>4776181
Ref: whatsnew/changelog id6534776293
Ref: 1b844776293
Ref: Documentation<50>-Footnote-14778371
Ref: Documentation<50>-Footnote-24778436
Ref: Documentation<50>-Footnote-34778501
Ref: Documentation<50>-Footnote-44778566
Ref: Documentation<50>-Footnote-54778631
Ref: Documentation<50>-Footnote-64778696
Ref: Documentation<50>-Footnote-74778761
Ref: Documentation<50>-Footnote-84778826
Ref: Documentation<50>-Footnote-94778891
Ref: Documentation<50>-Footnote-104778956
Ref: Documentation<50>-Footnote-114779022
Ref: Documentation<50>-Footnote-124779088
Ref: Documentation<50>-Footnote-134779154
Ref: Documentation<50>-Footnote-144779220
Node: Tests<52>4779286
Ref: whatsnew/changelog id6544779395
Ref: 1b854779395
Ref: Tests<52>-Footnote-14781033
Ref: Tests<52>-Footnote-24781098
Ref: Tests<52>-Footnote-34781163
Ref: Tests<52>-Footnote-44781228
Ref: Tests<52>-Footnote-54781293
Ref: Tests<52>-Footnote-64781358
Ref: Tests<52>-Footnote-74781423
Ref: Tests<52>-Footnote-84781488
Ref: Tests<52>-Footnote-94781553
Ref: Tests<52>-Footnote-104781618
Node: Build<57>4781684
Ref: whatsnew/changelog id6554781787
Ref: 1b874781787
Ref: Build<57>-Footnote-14783003
Ref: Build<57>-Footnote-24783068
Node: Windows<49>4783133
Ref: whatsnew/changelog id6564783236
Ref: 1b884783236
Ref: Windows<49>-Footnote-14783668
Ref: Windows<49>-Footnote-24783733
Ref: Windows<49>-Footnote-34783798
Ref: Windows<49>-Footnote-44783863
Node: macOS<40>4783928
Ref: whatsnew/changelog id6574784030
Ref: 1b894784030
Ref: macOS<40>-Footnote-14784332
Node: IDLE<37>4784397
Ref: whatsnew/changelog id6584784503
Ref: 1b8a4784503
Ref: IDLE<37>-Footnote-14785105
Ref: IDLE<37>-Footnote-24785170
Ref: IDLE<37>-Footnote-34785235
Ref: IDLE<37>-Footnote-44785300
Ref: IDLE<37>-Footnote-54785365
Ref: IDLE<37>-Footnote-64785430
Node: Tools/Demos<27>4785495
Ref: whatsnew/changelog id6594785601
Ref: 1b8b4785601
Ref: Tools/Demos<27>-Footnote-14785804
Node: C API<52>4785869
Ref: whatsnew/changelog id6604785958
Ref: 1b8c4785958
Ref: C API<52>-Footnote-14787298
Ref: C API<52>-Footnote-24787363
Ref: C API<52>-Footnote-34787405
Ref: C API<52>-Footnote-44787470
Ref: C API<52>-Footnote-54787535
Ref: C API<52>-Footnote-64787600
Ref: C API<52>-Footnote-74787642
Ref: C API<52>-Footnote-84787707
Ref: C API<52>-Footnote-94787772
Node: Python 3 8 0 alpha 44787837
Ref: whatsnew/changelog python-3-8-0-alpha-44787960
Ref: 1b8e4787960
Node: Security<41>4788343
Ref: whatsnew/changelog id6614788443
Ref: 1b8f4788443
Ref: Security<41>-Footnote-14789322
Ref: Security<41>-Footnote-24789387
Ref: Security<41>-Footnote-34789452
Ref: Security<41>-Footnote-44789507
Node: Core and Builtins<133>4789572
Ref: whatsnew/changelog id6624789693
Ref: 1b904789693
Ref: Core and Builtins<133>-Footnote-14792968
Ref: Core and Builtins<133>-Footnote-24793033
Ref: Core and Builtins<133>-Footnote-34793098
Ref: Core and Builtins<133>-Footnote-44793163
Ref: Core and Builtins<133>-Footnote-54793228
Ref: Core and Builtins<133>-Footnote-64793293
Ref: Core and Builtins<133>-Footnote-74793358
Ref: Core and Builtins<133>-Footnote-84793423
Ref: Core and Builtins<133>-Footnote-94793488
Ref: Core and Builtins<133>-Footnote-104793530
Ref: Core and Builtins<133>-Footnote-114793596
Ref: Core and Builtins<133>-Footnote-124793662
Ref: Core and Builtins<133>-Footnote-134793728
Ref: Core and Builtins<133>-Footnote-144793794
Ref: Core and Builtins<133>-Footnote-154793860
Ref: Core and Builtins<133>-Footnote-164793926
Ref: Core and Builtins<133>-Footnote-174793992
Ref: Core and Builtins<133>-Footnote-184794058
Ref: Core and Builtins<133>-Footnote-194794124
Ref: Core and Builtins<133>-Footnote-204794190
Node: Library<135>4794256
Ref: whatsnew/changelog id6634794382
Ref: 1b914794382
Ref: Library<135>-Footnote-14803699
Ref: Library<135>-Footnote-24803764
Ref: Library<135>-Footnote-34803829
Ref: Library<135>-Footnote-44803894
Ref: Library<135>-Footnote-54803961
Ref: Library<135>-Footnote-64804026
Ref: Library<135>-Footnote-74804091
Ref: Library<135>-Footnote-84804156
Ref: Library<135>-Footnote-94804221
Ref: Library<135>-Footnote-104804286
Ref: Library<135>-Footnote-114804352
Ref: Library<135>-Footnote-124804418
Ref: Library<135>-Footnote-134804484
Ref: Library<135>-Footnote-144804550
Ref: Library<135>-Footnote-154804616
Ref: Library<135>-Footnote-164804682
Ref: Library<135>-Footnote-174804748
Ref: Library<135>-Footnote-184804814
Ref: Library<135>-Footnote-194804880
Ref: Library<135>-Footnote-204804946
Ref: Library<135>-Footnote-214805012
Ref: Library<135>-Footnote-224805078
Ref: Library<135>-Footnote-234805144
Ref: Library<135>-Footnote-244805210
Ref: Library<135>-Footnote-254805276
Ref: Library<135>-Footnote-264805342
Ref: Library<135>-Footnote-274805408
Ref: Library<135>-Footnote-284805474
Ref: Library<135>-Footnote-294805540
Ref: Library<135>-Footnote-304805606
Ref: Library<135>-Footnote-314805672
Ref: Library<135>-Footnote-324805738
Ref: Library<135>-Footnote-334805804
Ref: Library<135>-Footnote-344805870
Ref: Library<135>-Footnote-354805936
Ref: Library<135>-Footnote-364806002
Ref: Library<135>-Footnote-374806068
Ref: Library<135>-Footnote-384806134
Ref: Library<135>-Footnote-394806200
Ref: Library<135>-Footnote-404806266
Ref: Library<135>-Footnote-414806332
Ref: Library<135>-Footnote-424806398
Ref: Library<135>-Footnote-434806464
Ref: Library<135>-Footnote-444806530
Ref: Library<135>-Footnote-454806596
Ref: Library<135>-Footnote-464806662
Ref: Library<135>-Footnote-474806728
Ref: Library<135>-Footnote-484806794
Ref: Library<135>-Footnote-494806860
Ref: Library<135>-Footnote-504806926
Ref: Library<135>-Footnote-514806992
Ref: Library<135>-Footnote-524807058
Ref: Library<135>-Footnote-534807124
Ref: Library<135>-Footnote-544807190
Node: Documentation<51>4807256
Ref: whatsnew/changelog id6644807369
Ref: 1b954807369
Ref: Documentation<51>-Footnote-14808820
Ref: Documentation<51>-Footnote-24808885
Ref: Documentation<51>-Footnote-34808950
Ref: Documentation<51>-Footnote-44809015
Ref: Documentation<51>-Footnote-54809080
Ref: Documentation<51>-Footnote-64809119
Ref: Documentation<51>-Footnote-74809184
Ref: Documentation<51>-Footnote-84809249
Ref: Documentation<51>-Footnote-94809314
Ref: Documentation<51>-Footnote-104809379
Ref: Documentation<51>-Footnote-114809445
Ref: Documentation<51>-Footnote-124809511
Node: Tests<53>4809577
Ref: whatsnew/changelog id6654809687
Ref: 1b964809687
Ref: Tests<53>-Footnote-14811937
Ref: Tests<53>-Footnote-24812002
Ref: Tests<53>-Footnote-34812067
Ref: Tests<53>-Footnote-44812132
Ref: Tests<53>-Footnote-54812197
Ref: Tests<53>-Footnote-64812262
Ref: Tests<53>-Footnote-74812327
Ref: Tests<53>-Footnote-84812392
Ref: Tests<53>-Footnote-94812457
Ref: Tests<53>-Footnote-104812522
Ref: Tests<53>-Footnote-114812588
Ref: Tests<53>-Footnote-124812654
Ref: Tests<53>-Footnote-134812720
Ref: Tests<53>-Footnote-144812786
Ref: Tests<53>-Footnote-154812852
Node: Build<58>4812918
Ref: whatsnew/changelog id6664813022
Ref: 1b984813022
Ref: Build<58>-Footnote-14816193
Ref: Build<58>-Footnote-24816258
Ref: Build<58>-Footnote-34816323
Ref: Build<58>-Footnote-44816388
Ref: Build<58>-Footnote-54816453
Ref: Build<58>-Footnote-64816518
Ref: Build<58>-Footnote-74816583
Ref: Build<58>-Footnote-84816648
Ref: Build<58>-Footnote-94816713
Ref: Build<58>-Footnote-104816778
Ref: Build<58>-Footnote-114816844
Ref: Build<58>-Footnote-124816910
Ref: Build<58>-Footnote-134816976
Node: Windows<50>4817042
Ref: whatsnew/changelog id6674817146
Ref: 1b994817146
Ref: Windows<50>-Footnote-14819798
Ref: Windows<50>-Footnote-24819863
Ref: Windows<50>-Footnote-34819928
Ref: Windows<50>-Footnote-44819993
Ref: Windows<50>-Footnote-54820058
Ref: Windows<50>-Footnote-64820123
Ref: Windows<50>-Footnote-74820188
Ref: Windows<50>-Footnote-84820253
Ref: Windows<50>-Footnote-94820318
Ref: Windows<50>-Footnote-104820383
Ref: Windows<50>-Footnote-114820449
Ref: Windows<50>-Footnote-124820515
Node: macOS<41>4820581
Ref: whatsnew/changelog id6684820684
Ref: 1b9a4820684
Ref: macOS<41>-Footnote-14820998
Ref: macOS<41>-Footnote-24821063
Node: IDLE<38>4821128
Ref: whatsnew/changelog id6694821235
Ref: 1b9b4821235
Ref: IDLE<38>-Footnote-14821482
Node: Tools/Demos<28>4821547
Ref: whatsnew/changelog id6704821654
Ref: 1b9c4821654
Ref: Tools/Demos<28>-Footnote-14821808
Node: C API<53>4821873
Ref: whatsnew/changelog id6714821963
Ref: 1b9d4821963
Ref: C API<53>-Footnote-14823968
Ref: C API<53>-Footnote-24824033
Ref: C API<53>-Footnote-34824098
Ref: C API<53>-Footnote-44824163
Ref: C API<53>-Footnote-54824228
Ref: C API<53>-Footnote-64824293
Node: Python 3 8 0 alpha 34824358
Ref: whatsnew/changelog python-3-8-0-alpha-34824482
Ref: 1ba04824482
Node: Security<42>4824845
Ref: whatsnew/changelog id6724824945
Ref: 1ba14824945
Ref: Security<42>-Footnote-14825509
Ref: Security<42>-Footnote-24825574
Node: Core and Builtins<134>4825639
Ref: whatsnew/changelog id6734825760
Ref: 1ba34825760
Ref: Core and Builtins<134>-Footnote-14829342
Ref: Core and Builtins<134>-Footnote-24829407
Ref: Core and Builtins<134>-Footnote-34829472
Ref: Core and Builtins<134>-Footnote-44829537
Ref: Core and Builtins<134>-Footnote-54829602
Ref: Core and Builtins<134>-Footnote-64829667
Ref: Core and Builtins<134>-Footnote-74829732
Ref: Core and Builtins<134>-Footnote-84829797
Ref: Core and Builtins<134>-Footnote-94829862
Ref: Core and Builtins<134>-Footnote-104829927
Ref: Core and Builtins<134>-Footnote-114829993
Ref: Core and Builtins<134>-Footnote-124830059
Ref: Core and Builtins<134>-Footnote-134830125
Ref: Core and Builtins<134>-Footnote-144830191
Ref: Core and Builtins<134>-Footnote-154830257
Ref: Core and Builtins<134>-Footnote-164830323
Ref: Core and Builtins<134>-Footnote-174830389
Ref: Core and Builtins<134>-Footnote-184830455
Ref: Core and Builtins<134>-Footnote-194830521
Ref: Core and Builtins<134>-Footnote-204830587
Ref: Core and Builtins<134>-Footnote-214830653
Ref: Core and Builtins<134>-Footnote-224830719
Node: Library<136>4830785
Ref: whatsnew/changelog id6744830911
Ref: 1ba54830911
Ref: Library<136>-Footnote-14836529
Ref: Library<136>-Footnote-24836594
Ref: Library<136>-Footnote-34836659
Ref: Library<136>-Footnote-44836724
Ref: Library<136>-Footnote-54836789
Ref: Library<136>-Footnote-64836854
Ref: Library<136>-Footnote-74836919
Ref: Library<136>-Footnote-84836984
Ref: Library<136>-Footnote-94837049
Ref: Library<136>-Footnote-104837114
Ref: Library<136>-Footnote-114837180
Ref: Library<136>-Footnote-124837246
Ref: Library<136>-Footnote-134837312
Ref: Library<136>-Footnote-144837378
Ref: Library<136>-Footnote-154837444
Ref: Library<136>-Footnote-164837510
Ref: Library<136>-Footnote-174837576
Ref: Library<136>-Footnote-184837642
Ref: Library<136>-Footnote-194837708
Ref: Library<136>-Footnote-204837774
Ref: Library<136>-Footnote-214837840
Ref: Library<136>-Footnote-224837906
Ref: Library<136>-Footnote-234837972
Ref: Library<136>-Footnote-244838038
Ref: Library<136>-Footnote-254838104
Ref: Library<136>-Footnote-264838170
Ref: Library<136>-Footnote-274838236
Ref: Library<136>-Footnote-284838302
Ref: Library<136>-Footnote-294838368
Ref: Library<136>-Footnote-304838434
Ref: Library<136>-Footnote-314838500
Ref: Library<136>-Footnote-324838566
Ref: Library<136>-Footnote-334838632
Ref: Library<136>-Footnote-344838698
Ref: Library<136>-Footnote-354838764
Ref: Library<136>-Footnote-364838830
Ref: Library<136>-Footnote-374838896
Node: Documentation<52>4838962
Ref: whatsnew/changelog id6754839075
Ref: 1ba74839075
Ref: Documentation<52>-Footnote-14839646
Ref: Documentation<52>-Footnote-24839711
Ref: Documentation<52>-Footnote-34839776
Node: Tests<54>4839841
Ref: whatsnew/changelog id6764839951
Ref: 1ba84839951
Ref: Tests<54>-Footnote-14840463
Ref: Tests<54>-Footnote-24840528
Ref: Tests<54>-Footnote-34840593
Node: Build<59>4840658
Ref: whatsnew/changelog id6774840762
Ref: 1ba94840762
Ref: Build<59>-Footnote-14841282
Ref: Build<59>-Footnote-24841347
Ref: Build<59>-Footnote-34841412
Ref: Build<59>-Footnote-44841477
Node: Windows<51>4841542
Ref: whatsnew/changelog id6784841645
Ref: 1baa4841645
Ref: Windows<51>-Footnote-14842096
Ref: Windows<51>-Footnote-24842161
Ref: Windows<51>-Footnote-34842226
Node: IDLE<39>4842291
Ref: whatsnew/changelog id6794842400
Ref: 1bab4842400
Ref: IDLE<39>-Footnote-14843509
Ref: IDLE<39>-Footnote-24843574
Ref: IDLE<39>-Footnote-34843639
Ref: IDLE<39>-Footnote-44843704
Ref: IDLE<39>-Footnote-54843769
Ref: IDLE<39>-Footnote-64843834
Ref: IDLE<39>-Footnote-74843899
Ref: IDLE<39>-Footnote-84843964
Ref: IDLE<39>-Footnote-94844029
Node: Tools/Demos<29>4844094
Ref: whatsnew/changelog id6804844201
Ref: 1bac4844201
Ref: Tools/Demos<29>-Footnote-14844414
Ref: Tools/Demos<29>-Footnote-24844479
Node: C API<54>4844544
Ref: whatsnew/changelog id6814844634
Ref: 1bad4844634
Ref: C API<54>-Footnote-14845026
Ref: C API<54>-Footnote-24845091
Node: Python 3 8 0 alpha 24845156
Ref: whatsnew/changelog python-3-8-0-alpha-24845280
Ref: 1bae4845280
Node: Core and Builtins<135>4845545
Ref: whatsnew/changelog id6824845645
Ref: 1baf4845645
Ref: Core and Builtins<135>-Footnote-14848784
Ref: Core and Builtins<135>-Footnote-24848849
Ref: Core and Builtins<135>-Footnote-34848914
Ref: Core and Builtins<135>-Footnote-44848979
Ref: Core and Builtins<135>-Footnote-54849044
Ref: Core and Builtins<135>-Footnote-64849111
Ref: Core and Builtins<135>-Footnote-74849176
Ref: Core and Builtins<135>-Footnote-84849241
Ref: Core and Builtins<135>-Footnote-94849306
Ref: Core and Builtins<135>-Footnote-104849371
Ref: Core and Builtins<135>-Footnote-114849437
Ref: Core and Builtins<135>-Footnote-124849503
Ref: Core and Builtins<135>-Footnote-134849569
Ref: Core and Builtins<135>-Footnote-144849635
Ref: Core and Builtins<135>-Footnote-154849701
Ref: Core and Builtins<135>-Footnote-164849767
Ref: Core and Builtins<135>-Footnote-174849833
Node: Library<137>4849899
Ref: whatsnew/changelog id6834850025
Ref: 1bb04850025
Ref: Library<137>-Footnote-14853734
Ref: Library<137>-Footnote-24853799
Ref: Library<137>-Footnote-34853864
Ref: Library<137>-Footnote-44853929
Ref: Library<137>-Footnote-54853994
Ref: Library<137>-Footnote-64854059
Ref: Library<137>-Footnote-74854124
Ref: Library<137>-Footnote-84854189
Ref: Library<137>-Footnote-94854254
Ref: Library<137>-Footnote-104854319
Ref: Library<137>-Footnote-114854385
Ref: Library<137>-Footnote-124854451
Ref: Library<137>-Footnote-134854517
Ref: Library<137>-Footnote-144854583
Ref: Library<137>-Footnote-154854649
Ref: Library<137>-Footnote-164854715
Ref: Library<137>-Footnote-174854781
Node: Documentation<53>4854847
Ref: whatsnew/changelog id6844854960
Ref: 1bb34854960
Ref: Documentation<53>-Footnote-14855338
Ref: Documentation<53>-Footnote-24855403
Ref: Documentation<53>-Footnote-34855468
Node: Tests<55>4855533
Ref: whatsnew/changelog id6854855645
Ref: 1bb44855645
Ref: Tests<55>-Footnote-14857010
Ref: Tests<55>-Footnote-24857075
Ref: Tests<55>-Footnote-34857140
Ref: Tests<55>-Footnote-44857205
Ref: Tests<55>-Footnote-54857270
Ref: Tests<55>-Footnote-64857335
Ref: Tests<55>-Footnote-74857400
Ref: Tests<55>-Footnote-84857465
Node: Windows<52>4857530
Ref: whatsnew/changelog id6864857633
Ref: 1bb54857633
Ref: Windows<52>-Footnote-14858230
Ref: Windows<52>-Footnote-24858295
Ref: Windows<52>-Footnote-34858360
Ref: Windows<52>-Footnote-44858425
Ref: Windows<52>-Footnote-54858490
Node: IDLE<40>4858555
Ref: whatsnew/changelog id6874858640
Ref: 1bb64858640
Ref: IDLE<40>-Footnote-14858946
Ref: IDLE<40>-Footnote-24859011
Ref: IDLE<40>-Footnote-34859076
Node: Python 3 8 0 alpha 14859141
Ref: whatsnew/changelog python-3-8-0-alpha-14859263
Ref: 1bb74859263
Node: Security<43>4859646
Ref: whatsnew/changelog id6884859746
Ref: 1bb84859746
Ref: Security<43>-Footnote-14862080
Ref: Security<43>-Footnote-24862145
Ref: Security<43>-Footnote-34862200
Ref: Security<43>-Footnote-44862265
Ref: Security<43>-Footnote-54862330
Ref: Security<43>-Footnote-64862395
Ref: Security<43>-Footnote-74862460
Ref: Security<43>-Footnote-84862516
Ref: Security<43>-Footnote-94862581
Ref: Security<43>-Footnote-104862646
Ref: Security<43>-Footnote-114862712
Ref: Security<43>-Footnote-124862778
Ref: Security<43>-Footnote-134862834
Ref: Security<43>-Footnote-144862900
Ref: Security<43>-Footnote-154862966
Ref: Security<43>-Footnote-164863022
Ref: Security<43>-Footnote-174863078
Node: Core and Builtins<136>4863144
Ref: whatsnew/changelog id6894863265
Ref: 1bb94863265
Ref: Core and Builtins<136>-Footnote-14889455
Ref: Core and Builtins<136>-Footnote-24889520
Ref: Core and Builtins<136>-Footnote-34889585
Ref: Core and Builtins<136>-Footnote-44889650
Ref: Core and Builtins<136>-Footnote-54889715
Ref: Core and Builtins<136>-Footnote-64889780
Ref: Core and Builtins<136>-Footnote-74889845
Ref: Core and Builtins<136>-Footnote-84889910
Ref: Core and Builtins<136>-Footnote-94889975
Ref: Core and Builtins<136>-Footnote-104890040
Ref: Core and Builtins<136>-Footnote-114890106
Ref: Core and Builtins<136>-Footnote-124890172
Ref: Core and Builtins<136>-Footnote-134890238
Ref: Core and Builtins<136>-Footnote-144890304
Ref: Core and Builtins<136>-Footnote-154890370
Ref: Core and Builtins<136>-Footnote-164890436
Ref: Core and Builtins<136>-Footnote-174890502
Ref: Core and Builtins<136>-Footnote-184890568
Ref: Core and Builtins<136>-Footnote-194890634
Ref: Core and Builtins<136>-Footnote-204890700
Ref: Core and Builtins<136>-Footnote-214890766
Ref: Core and Builtins<136>-Footnote-224890832
Ref: Core and Builtins<136>-Footnote-234890898
Ref: Core and Builtins<136>-Footnote-244890964
Ref: Core and Builtins<136>-Footnote-254891030
Ref: Core and Builtins<136>-Footnote-264891073
Ref: Core and Builtins<136>-Footnote-274891139
Ref: Core and Builtins<136>-Footnote-284891205
Ref: Core and Builtins<136>-Footnote-294891271
Ref: Core and Builtins<136>-Footnote-304891337
Ref: Core and Builtins<136>-Footnote-314891403
Ref: Core and Builtins<136>-Footnote-324891469
Ref: Core and Builtins<136>-Footnote-334891535
Ref: Core and Builtins<136>-Footnote-344891601
Ref: Core and Builtins<136>-Footnote-354891667
Ref: Core and Builtins<136>-Footnote-364891733
Ref: Core and Builtins<136>-Footnote-374891799
Ref: Core and Builtins<136>-Footnote-384891865
Ref: Core and Builtins<136>-Footnote-394891931
Ref: Core and Builtins<136>-Footnote-404891997
Ref: Core and Builtins<136>-Footnote-414892063
Ref: Core and Builtins<136>-Footnote-424892129
Ref: Core and Builtins<136>-Footnote-434892195
Ref: Core and Builtins<136>-Footnote-444892261
Ref: Core and Builtins<136>-Footnote-454892327
Ref: Core and Builtins<136>-Footnote-464892393
Ref: Core and Builtins<136>-Footnote-474892459
Ref: Core and Builtins<136>-Footnote-484892525
Ref: Core and Builtins<136>-Footnote-494892591
Ref: Core and Builtins<136>-Footnote-504892657
Ref: Core and Builtins<136>-Footnote-514892723
Ref: Core and Builtins<136>-Footnote-524892789
Ref: Core and Builtins<136>-Footnote-534892855
Ref: Core and Builtins<136>-Footnote-544892921
Ref: Core and Builtins<136>-Footnote-554892987
Ref: Core and Builtins<136>-Footnote-564893053
Ref: Core and Builtins<136>-Footnote-574893119
Ref: Core and Builtins<136>-Footnote-584893185
Ref: Core and Builtins<136>-Footnote-594893251
Ref: Core and Builtins<136>-Footnote-604893316
Ref: Core and Builtins<136>-Footnote-614893382
Ref: Core and Builtins<136>-Footnote-624893448
Ref: Core and Builtins<136>-Footnote-634893514
Ref: Core and Builtins<136>-Footnote-644893580
Ref: Core and Builtins<136>-Footnote-654893646
Ref: Core and Builtins<136>-Footnote-664893712
Ref: Core and Builtins<136>-Footnote-674893778
Ref: Core and Builtins<136>-Footnote-684893844
Ref: Core and Builtins<136>-Footnote-694893910
Ref: Core and Builtins<136>-Footnote-704893976
Ref: Core and Builtins<136>-Footnote-714894042
Ref: Core and Builtins<136>-Footnote-724894108
Ref: Core and Builtins<136>-Footnote-734894174
Ref: Core and Builtins<136>-Footnote-744894240
Ref: Core and Builtins<136>-Footnote-754894306
Ref: Core and Builtins<136>-Footnote-764894372
Ref: Core and Builtins<136>-Footnote-774894438
Ref: Core and Builtins<136>-Footnote-784894504
Ref: Core and Builtins<136>-Footnote-794894570
Ref: Core and Builtins<136>-Footnote-804894636
Ref: Core and Builtins<136>-Footnote-814894702
Ref: Core and Builtins<136>-Footnote-824894768
Ref: Core and Builtins<136>-Footnote-834894834
Ref: Core and Builtins<136>-Footnote-844894900
Ref: Core and Builtins<136>-Footnote-854894966
Ref: Core and Builtins<136>-Footnote-864895032
Ref: Core and Builtins<136>-Footnote-874895098
Ref: Core and Builtins<136>-Footnote-884895164
Ref: Core and Builtins<136>-Footnote-894895230
Ref: Core and Builtins<136>-Footnote-904895296
Ref: Core and Builtins<136>-Footnote-914895362
Ref: Core and Builtins<136>-Footnote-924895428
Ref: Core and Builtins<136>-Footnote-934895494
Ref: Core and Builtins<136>-Footnote-944895560
Ref: Core and Builtins<136>-Footnote-954895626
Ref: Core and Builtins<136>-Footnote-964895692
Ref: Core and Builtins<136>-Footnote-974895760
Ref: Core and Builtins<136>-Footnote-984895826
Ref: Core and Builtins<136>-Footnote-994895892
Ref: Core and Builtins<136>-Footnote-1004895958
Ref: Core and Builtins<136>-Footnote-1014896025
Ref: Core and Builtins<136>-Footnote-1024896092
Ref: Core and Builtins<136>-Footnote-1034896159
Ref: Core and Builtins<136>-Footnote-1044896226
Ref: Core and Builtins<136>-Footnote-1054896293
Ref: Core and Builtins<136>-Footnote-1064896360
Ref: Core and Builtins<136>-Footnote-1074896427
Ref: Core and Builtins<136>-Footnote-1084896494
Ref: Core and Builtins<136>-Footnote-1094896561
Ref: Core and Builtins<136>-Footnote-1104896628
Ref: Core and Builtins<136>-Footnote-1114896695
Ref: Core and Builtins<136>-Footnote-1124896762
Ref: Core and Builtins<136>-Footnote-1134896829
Ref: Core and Builtins<136>-Footnote-1144896896
Ref: Core and Builtins<136>-Footnote-1154896963
Ref: Core and Builtins<136>-Footnote-1164897030
Ref: Core and Builtins<136>-Footnote-1174897097
Ref: Core and Builtins<136>-Footnote-1184897164
Ref: Core and Builtins<136>-Footnote-1194897231
Ref: Core and Builtins<136>-Footnote-1204897298
Ref: Core and Builtins<136>-Footnote-1214897365
Ref: Core and Builtins<136>-Footnote-1224897432
Ref: Core and Builtins<136>-Footnote-1234897499
Ref: Core and Builtins<136>-Footnote-1244897566
Ref: Core and Builtins<136>-Footnote-1254897633
Ref: Core and Builtins<136>-Footnote-1264897700
Ref: Core and Builtins<136>-Footnote-1274897767
Ref: Core and Builtins<136>-Footnote-1284897834
Ref: Core and Builtins<136>-Footnote-1294897901
Ref: Core and Builtins<136>-Footnote-1304897968
Ref: Core and Builtins<136>-Footnote-1314898035
Ref: Core and Builtins<136>-Footnote-1324898102
Ref: Core and Builtins<136>-Footnote-1334898169
Ref: Core and Builtins<136>-Footnote-1344898236
Ref: Core and Builtins<136>-Footnote-1354898303
Ref: Core and Builtins<136>-Footnote-1364898370
Ref: Core and Builtins<136>-Footnote-1374898437
Ref: Core and Builtins<136>-Footnote-1384898504
Ref: Core and Builtins<136>-Footnote-1394898571
Ref: Core and Builtins<136>-Footnote-1404898638
Ref: Core and Builtins<136>-Footnote-1414898705
Ref: Core and Builtins<136>-Footnote-1424898772
Ref: Core and Builtins<136>-Footnote-1434898839
Ref: Core and Builtins<136>-Footnote-1444898906
Ref: Core and Builtins<136>-Footnote-1454898973
Ref: Core and Builtins<136>-Footnote-1464899040
Ref: Core and Builtins<136>-Footnote-1474899107
Ref: Core and Builtins<136>-Footnote-1484899174
Ref: Core and Builtins<136>-Footnote-1494899241
Ref: Core and Builtins<136>-Footnote-1504899308
Ref: Core and Builtins<136>-Footnote-1514899375
Ref: Core and Builtins<136>-Footnote-1524899442
Ref: Core and Builtins<136>-Footnote-1534899509
Ref: Core and Builtins<136>-Footnote-1544899576
Ref: Core and Builtins<136>-Footnote-1554899643
Ref: Core and Builtins<136>-Footnote-1564899710
Ref: Core and Builtins<136>-Footnote-1574899777
Ref: Core and Builtins<136>-Footnote-1584899844
Ref: Core and Builtins<136>-Footnote-1594899911
Ref: Core and Builtins<136>-Footnote-1604899978
Ref: Core and Builtins<136>-Footnote-1614900045
Ref: Core and Builtins<136>-Footnote-1624900112
Node: Library<138>4900179
Ref: whatsnew/changelog id6904900305
Ref: 1bbf4900305
Ref: Library<138>-Footnote-14971452
Ref: Library<138>-Footnote-24971517
Ref: Library<138>-Footnote-34971582
Ref: Library<138>-Footnote-44971647
Ref: Library<138>-Footnote-54971712
Ref: Library<138>-Footnote-64971777
Ref: Library<138>-Footnote-74971842
Ref: Library<138>-Footnote-84971907
Ref: Library<138>-Footnote-94971972
Ref: Library<138>-Footnote-104972037
Ref: Library<138>-Footnote-114972103
Ref: Library<138>-Footnote-124972169
Ref: Library<138>-Footnote-134972235
Ref: Library<138>-Footnote-144972301
Ref: Library<138>-Footnote-154972367
Ref: Library<138>-Footnote-164972433
Ref: Library<138>-Footnote-174972499
Ref: Library<138>-Footnote-184972565
Ref: Library<138>-Footnote-194972631
Ref: Library<138>-Footnote-204972697
Ref: Library<138>-Footnote-214972763
Ref: Library<138>-Footnote-224972829
Ref: Library<138>-Footnote-234972895
Ref: Library<138>-Footnote-244972961
Ref: Library<138>-Footnote-254973027
Ref: Library<138>-Footnote-264973093
Ref: Library<138>-Footnote-274973159
Ref: Library<138>-Footnote-284973225
Ref: Library<138>-Footnote-294973291
Ref: Library<138>-Footnote-304973357
Ref: Library<138>-Footnote-314973423
Ref: Library<138>-Footnote-324973489
Ref: Library<138>-Footnote-334973555
Ref: Library<138>-Footnote-344973621
Ref: Library<138>-Footnote-354973687
Ref: Library<138>-Footnote-364973753
Ref: Library<138>-Footnote-374973819
Ref: Library<138>-Footnote-384973885
Ref: Library<138>-Footnote-394973951
Ref: Library<138>-Footnote-404974017
Ref: Library<138>-Footnote-414974083
Ref: Library<138>-Footnote-424974149
Ref: Library<138>-Footnote-434974215
Ref: Library<138>-Footnote-444974281
Ref: Library<138>-Footnote-454974347
Ref: Library<138>-Footnote-464974413
Ref: Library<138>-Footnote-474974479
Ref: Library<138>-Footnote-484974545
Ref: Library<138>-Footnote-494974611
Ref: Library<138>-Footnote-504974677
Ref: Library<138>-Footnote-514974743
Ref: Library<138>-Footnote-524974809
Ref: Library<138>-Footnote-534974875
Ref: Library<138>-Footnote-544974941
Ref: Library<138>-Footnote-554975007
Ref: Library<138>-Footnote-564975073
Ref: Library<138>-Footnote-574975139
Ref: Library<138>-Footnote-584975205
Ref: Library<138>-Footnote-594975271
Ref: Library<138>-Footnote-604975337
Ref: Library<138>-Footnote-614975403
Ref: Library<138>-Footnote-624975469
Ref: Library<138>-Footnote-634975535
Ref: Library<138>-Footnote-644975601
Ref: Library<138>-Footnote-654975667
Ref: Library<138>-Footnote-664975733
Ref: Library<138>-Footnote-674975799
Ref: Library<138>-Footnote-684975865
Ref: Library<138>-Footnote-694975931
Ref: Library<138>-Footnote-704975997
Ref: Library<138>-Footnote-714976063
Ref: Library<138>-Footnote-724976129
Ref: Library<138>-Footnote-734976195
Ref: Library<138>-Footnote-744976261
Ref: Library<138>-Footnote-754976327
Ref: Library<138>-Footnote-764976393
Ref: Library<138>-Footnote-774976459
Ref: Library<138>-Footnote-784976525
Ref: Library<138>-Footnote-794976591
Ref: Library<138>-Footnote-804976657
Ref: Library<138>-Footnote-814976723
Ref: Library<138>-Footnote-824976789
Ref: Library<138>-Footnote-834976855
Ref: Library<138>-Footnote-844976921
Ref: Library<138>-Footnote-854976987
Ref: Library<138>-Footnote-864977053
Ref: Library<138>-Footnote-874977119
Ref: Library<138>-Footnote-884977185
Ref: Library<138>-Footnote-894977251
Ref: Library<138>-Footnote-904977317
Ref: Library<138>-Footnote-914977383
Ref: Library<138>-Footnote-924977449
Ref: Library<138>-Footnote-934977515
Ref: Library<138>-Footnote-944977575
Ref: Library<138>-Footnote-954977641
Ref: Library<138>-Footnote-964977707
Ref: Library<138>-Footnote-974977773
Ref: Library<138>-Footnote-984977839
Ref: Library<138>-Footnote-994977905
Ref: Library<138>-Footnote-1004977971
Ref: Library<138>-Footnote-1014978038
Ref: Library<138>-Footnote-1024978105
Ref: Library<138>-Footnote-1034978172
Ref: Library<138>-Footnote-1044978239
Ref: Library<138>-Footnote-1054978306
Ref: Library<138>-Footnote-1064978373
Ref: Library<138>-Footnote-1074978440
Ref: Library<138>-Footnote-1084978507
Ref: Library<138>-Footnote-1094978574
Ref: Library<138>-Footnote-1104978641
Ref: Library<138>-Footnote-1114978708
Ref: Library<138>-Footnote-1124978775
Ref: Library<138>-Footnote-1134978842
Ref: Library<138>-Footnote-1144978909
Ref: Library<138>-Footnote-1154978976
Ref: Library<138>-Footnote-1164979043
Ref: Library<138>-Footnote-1174979110
Ref: Library<138>-Footnote-1184979177
Ref: Library<138>-Footnote-1194979244
Ref: Library<138>-Footnote-1204979311
Ref: Library<138>-Footnote-1214979378
Ref: Library<138>-Footnote-1224979445
Ref: Library<138>-Footnote-1234979512
Ref: Library<138>-Footnote-1244979579
Ref: Library<138>-Footnote-1254979646
Ref: Library<138>-Footnote-1264979712
Ref: Library<138>-Footnote-1274979779
Ref: Library<138>-Footnote-1284979846
Ref: Library<138>-Footnote-1294979913
Ref: Library<138>-Footnote-1304979980
Ref: Library<138>-Footnote-1314980047
Ref: Library<138>-Footnote-1324980114
Ref: Library<138>-Footnote-1334980181
Ref: Library<138>-Footnote-1344980248
Ref: Library<138>-Footnote-1354980315
Ref: Library<138>-Footnote-1364980382
Ref: Library<138>-Footnote-1374980448
Ref: Library<138>-Footnote-1384980515
Ref: Library<138>-Footnote-1394980582
Ref: Library<138>-Footnote-1404980649
Ref: Library<138>-Footnote-1414980716
Ref: Library<138>-Footnote-1424980783
Ref: Library<138>-Footnote-1434980850
Ref: Library<138>-Footnote-1444980917
Ref: Library<138>-Footnote-1454980984
Ref: Library<138>-Footnote-1464981051
Ref: Library<138>-Footnote-1474981118
Ref: Library<138>-Footnote-1484981185
Ref: Library<138>-Footnote-1494981252
Ref: Library<138>-Footnote-1504981319
Ref: Library<138>-Footnote-1514981386
Ref: Library<138>-Footnote-1524981453
Ref: Library<138>-Footnote-1534981520
Ref: Library<138>-Footnote-1544981587
Ref: Library<138>-Footnote-1554981653
Ref: Library<138>-Footnote-1564981720
Ref: Library<138>-Footnote-1574981787
Ref: Library<138>-Footnote-1584981854
Ref: Library<138>-Footnote-1594981921
Ref: Library<138>-Footnote-1604981988
Ref: Library<138>-Footnote-1614982055
Ref: Library<138>-Footnote-1624982099
Ref: Library<138>-Footnote-1634982166
Ref: Library<138>-Footnote-1644982233
Ref: Library<138>-Footnote-1654982300
Ref: Library<138>-Footnote-1664982366
Ref: Library<138>-Footnote-1674982433
Ref: Library<138>-Footnote-1684982500
Ref: Library<138>-Footnote-1694982567
Ref: Library<138>-Footnote-1704982634
Ref: Library<138>-Footnote-1714982701
Ref: Library<138>-Footnote-1724982768
Ref: Library<138>-Footnote-1734982835
Ref: Library<138>-Footnote-1744982902
Ref: Library<138>-Footnote-1754982968
Ref: Library<138>-Footnote-1764983035
Ref: Library<138>-Footnote-1774983102
Ref: Library<138>-Footnote-1784983169
Ref: Library<138>-Footnote-1794983236
Ref: Library<138>-Footnote-1804983303
Ref: Library<138>-Footnote-1814983369
Ref: Library<138>-Footnote-1824983436
Ref: Library<138>-Footnote-1834983503
Ref: Library<138>-Footnote-1844983570
Ref: Library<138>-Footnote-1854983637
Ref: Library<138>-Footnote-1864983704
Ref: Library<138>-Footnote-1874983771
Ref: Library<138>-Footnote-1884983838
Ref: Library<138>-Footnote-1894983905
Ref: Library<138>-Footnote-1904983972
Ref: Library<138>-Footnote-1914984039
Ref: Library<138>-Footnote-1924984106
Ref: Library<138>-Footnote-1934984173
Ref: Library<138>-Footnote-1944984240
Ref: Library<138>-Footnote-1954984307
Ref: Library<138>-Footnote-1964984374
Ref: Library<138>-Footnote-1974984441
Ref: Library<138>-Footnote-1984984508
Ref: Library<138>-Footnote-1994984575
Ref: Library<138>-Footnote-2004984642
Ref: Library<138>-Footnote-2014984709
Ref: Library<138>-Footnote-2024984776
Ref: Library<138>-Footnote-2034984844
Ref: Library<138>-Footnote-2044984911
Ref: Library<138>-Footnote-2054984978
Ref: Library<138>-Footnote-2064985045
Ref: Library<138>-Footnote-2074985112
Ref: Library<138>-Footnote-2084985179
Ref: Library<138>-Footnote-2094985246
Ref: Library<138>-Footnote-2104985313
Ref: Library<138>-Footnote-2114985380
Ref: Library<138>-Footnote-2124985447
Ref: Library<138>-Footnote-2134985514
Ref: Library<138>-Footnote-2144985558
Ref: Library<138>-Footnote-2154985625
Ref: Library<138>-Footnote-2164985692
Ref: Library<138>-Footnote-2174985759
Ref: Library<138>-Footnote-2184985826
Ref: Library<138>-Footnote-2194985893
Ref: Library<138>-Footnote-2204985960
Ref: Library<138>-Footnote-2214986027
Ref: Library<138>-Footnote-2224986094
Ref: Library<138>-Footnote-2234986161
Ref: Library<138>-Footnote-2244986228
Ref: Library<138>-Footnote-2254986295
Ref: Library<138>-Footnote-2264986362
Ref: Library<138>-Footnote-2274986429
Ref: Library<138>-Footnote-2284986496
Ref: Library<138>-Footnote-2294986563
Ref: Library<138>-Footnote-2304986630
Ref: Library<138>-Footnote-2314986697
Ref: Library<138>-Footnote-2324986764
Ref: Library<138>-Footnote-2334986831
Ref: Library<138>-Footnote-2344986898
Ref: Library<138>-Footnote-2354986965
Ref: Library<138>-Footnote-2364987032
Ref: Library<138>-Footnote-2374987099
Ref: Library<138>-Footnote-2384987166
Ref: Library<138>-Footnote-2394987233
Ref: Library<138>-Footnote-2404987300
Ref: Library<138>-Footnote-2414987367
Ref: Library<138>-Footnote-2424987434
Ref: Library<138>-Footnote-2434987501
Ref: Library<138>-Footnote-2444987568
Ref: Library<138>-Footnote-2454987635
Ref: Library<138>-Footnote-2464987702
Ref: Library<138>-Footnote-2474987769
Ref: Library<138>-Footnote-2484987836
Ref: Library<138>-Footnote-2494987903
Ref: Library<138>-Footnote-2504987970
Ref: Library<138>-Footnote-2514988037
Ref: Library<138>-Footnote-2524988104
Ref: Library<138>-Footnote-2534988171
Ref: Library<138>-Footnote-2544988238
Ref: Library<138>-Footnote-2554988305
Ref: Library<138>-Footnote-2564988372
Ref: Library<138>-Footnote-2574988439
Ref: Library<138>-Footnote-2584988506
Ref: Library<138>-Footnote-2594988573
Ref: Library<138>-Footnote-2604988640
Ref: Library<138>-Footnote-2614988706
Ref: Library<138>-Footnote-2624988773
Ref: Library<138>-Footnote-2634988840
Ref: Library<138>-Footnote-2644988907
Ref: Library<138>-Footnote-2654988974
Ref: Library<138>-Footnote-2664989041
Ref: Library<138>-Footnote-2674989108
Ref: Library<138>-Footnote-2684989175
Ref: Library<138>-Footnote-2694989242
Ref: Library<138>-Footnote-2704989309
Ref: Library<138>-Footnote-2714989376
Ref: Library<138>-Footnote-2724989443
Ref: Library<138>-Footnote-2734989510
Ref: Library<138>-Footnote-2744989577
Ref: Library<138>-Footnote-2754989644
Ref: Library<138>-Footnote-2764989711
Ref: Library<138>-Footnote-2774989778
Ref: Library<138>-Footnote-2784989845
Ref: Library<138>-Footnote-2794989912
Ref: Library<138>-Footnote-2804989979
Ref: Library<138>-Footnote-2814990046
Ref: Library<138>-Footnote-2824990113
Ref: Library<138>-Footnote-2834990180
Ref: Library<138>-Footnote-2844990247
Ref: Library<138>-Footnote-2854990314
Ref: Library<138>-Footnote-2864990381
Ref: Library<138>-Footnote-2874990448
Ref: Library<138>-Footnote-2884990515
Ref: Library<138>-Footnote-2894990582
Ref: Library<138>-Footnote-2904990649
Ref: Library<138>-Footnote-2914990716
Ref: Library<138>-Footnote-2924990783
Ref: Library<138>-Footnote-2934990850
Ref: Library<138>-Footnote-2944990917
Ref: Library<138>-Footnote-2954990984
Ref: Library<138>-Footnote-2964991051
Ref: Library<138>-Footnote-2974991118
Ref: Library<138>-Footnote-2984991185
Ref: Library<138>-Footnote-2994991252
Ref: Library<138>-Footnote-3004991319
Ref: Library<138>-Footnote-3014991386
Ref: Library<138>-Footnote-3024991453
Ref: Library<138>-Footnote-3034991520
Ref: Library<138>-Footnote-3044991587
Ref: Library<138>-Footnote-3054991654
Ref: Library<138>-Footnote-3064991721
Ref: Library<138>-Footnote-3074991788
Ref: Library<138>-Footnote-3084991855
Ref: Library<138>-Footnote-3094991922
Ref: Library<138>-Footnote-3104991989
Ref: Library<138>-Footnote-3114992056
Ref: Library<138>-Footnote-3124992123
Ref: Library<138>-Footnote-3134992190
Ref: Library<138>-Footnote-3144992257
Ref: Library<138>-Footnote-3154992324
Ref: Library<138>-Footnote-3164992391
Ref: Library<138>-Footnote-3174992458
Ref: Library<138>-Footnote-3184992525
Ref: Library<138>-Footnote-3194992592
Ref: Library<138>-Footnote-3204992659
Ref: Library<138>-Footnote-3214992726
Ref: Library<138>-Footnote-3224992793
Ref: Library<138>-Footnote-3234992860
Ref: Library<138>-Footnote-3244992927
Ref: Library<138>-Footnote-3254992994
Ref: Library<138>-Footnote-3264993061
Ref: Library<138>-Footnote-3274993128
Ref: Library<138>-Footnote-3284993195
Ref: Library<138>-Footnote-3294993263
Ref: Library<138>-Footnote-3304993330
Ref: Library<138>-Footnote-3314993397
Ref: Library<138>-Footnote-3324993464
Ref: Library<138>-Footnote-3334993531
Ref: Library<138>-Footnote-3344993598
Ref: Library<138>-Footnote-3354993665
Ref: Library<138>-Footnote-3364993732
Ref: Library<138>-Footnote-3374993799
Ref: Library<138>-Footnote-3384993866
Ref: Library<138>-Footnote-3394993933
Ref: Library<138>-Footnote-3404994000
Ref: Library<138>-Footnote-3414994067
Ref: Library<138>-Footnote-3424994134
Ref: Library<138>-Footnote-3434994201
Ref: Library<138>-Footnote-3444994268
Ref: Library<138>-Footnote-3454994335
Ref: Library<138>-Footnote-3464994379
Ref: Library<138>-Footnote-3474994446
Ref: Library<138>-Footnote-3484994513
Ref: Library<138>-Footnote-3494994580
Ref: Library<138>-Footnote-3504994624
Ref: Library<138>-Footnote-3514994691
Ref: Library<138>-Footnote-3524994758
Ref: Library<138>-Footnote-3534994825
Ref: Library<138>-Footnote-3544994892
Ref: Library<138>-Footnote-3554994959
Ref: Library<138>-Footnote-3564995026
Ref: Library<138>-Footnote-3574995093
Ref: Library<138>-Footnote-3584995160
Ref: Library<138>-Footnote-3594995227
Ref: Library<138>-Footnote-3604995294
Ref: Library<138>-Footnote-3614995361
Ref: Library<138>-Footnote-3624995428
Ref: Library<138>-Footnote-3634995495
Ref: Library<138>-Footnote-3644995562
Ref: Library<138>-Footnote-3654995629
Ref: Library<138>-Footnote-3664995696
Ref: Library<138>-Footnote-3674995763
Ref: Library<138>-Footnote-3684995830
Ref: Library<138>-Footnote-3694995897
Ref: Library<138>-Footnote-3704995964
Ref: Library<138>-Footnote-3714996031
Ref: Library<138>-Footnote-3724996098
Ref: Library<138>-Footnote-3734996165
Ref: Library<138>-Footnote-3744996232
Ref: Library<138>-Footnote-3754996299
Ref: Library<138>-Footnote-3764996366
Ref: Library<138>-Footnote-3774996433
Ref: Library<138>-Footnote-3784996500
Ref: Library<138>-Footnote-3794996567
Ref: Library<138>-Footnote-3804996634
Ref: Library<138>-Footnote-3814996701
Ref: Library<138>-Footnote-3824996768
Ref: Library<138>-Footnote-3834996835
Ref: Library<138>-Footnote-3844996902
Ref: Library<138>-Footnote-3854996969
Ref: Library<138>-Footnote-3864997036
Ref: Library<138>-Footnote-3874997103
Ref: Library<138>-Footnote-3884997170
Ref: Library<138>-Footnote-3894997237
Ref: Library<138>-Footnote-3904997304
Ref: Library<138>-Footnote-3914997371
Ref: Library<138>-Footnote-3924997438
Ref: Library<138>-Footnote-3934997505
Ref: Library<138>-Footnote-3944997572
Ref: Library<138>-Footnote-3954997639
Ref: Library<138>-Footnote-3964997706
Ref: Library<138>-Footnote-3974997773
Ref: Library<138>-Footnote-3984997840
Ref: Library<138>-Footnote-3994997907
Ref: Library<138>-Footnote-4004997974
Ref: Library<138>-Footnote-4014998041
Ref: Library<138>-Footnote-4024998108
Ref: Library<138>-Footnote-4034998175
Ref: Library<138>-Footnote-4044998242
Ref: Library<138>-Footnote-4054998309
Ref: Library<138>-Footnote-4064998376
Ref: Library<138>-Footnote-4074998443
Ref: Library<138>-Footnote-4084998510
Ref: Library<138>-Footnote-4094998577
Ref: Library<138>-Footnote-4104998644
Ref: Library<138>-Footnote-4114998711
Ref: Library<138>-Footnote-4124998778
Ref: Library<138>-Footnote-4134998845
Ref: Library<138>-Footnote-4144998912
Ref: Library<138>-Footnote-4154998979
Ref: Library<138>-Footnote-4164999046
Ref: Library<138>-Footnote-4174999113
Ref: Library<138>-Footnote-4184999180
Ref: Library<138>-Footnote-4194999247
Ref: Library<138>-Footnote-4204999314
Ref: Library<138>-Footnote-4214999381
Ref: Library<138>-Footnote-4224999448
Ref: Library<138>-Footnote-4234999514
Ref: Library<138>-Footnote-4244999581
Ref: Library<138>-Footnote-4254999648
Ref: Library<138>-Footnote-4264999715
Ref: Library<138>-Footnote-4274999782
Ref: Library<138>-Footnote-4284999849
Ref: Library<138>-Footnote-4294999916
Ref: Library<138>-Footnote-4304999983
Ref: Library<138>-Footnote-4315000050
Ref: Library<138>-Footnote-4325000117
Ref: Library<138>-Footnote-4335000184
Ref: Library<138>-Footnote-4345000251
Ref: Library<138>-Footnote-4355000318
Ref: Library<138>-Footnote-4365000385
Ref: Library<138>-Footnote-4375000452
Node: Documentation<54>5000519
Ref: whatsnew/changelog id6915000632
Ref: 1bd85000632
Ref: Documentation<54>-Footnote-15007323
Ref: Documentation<54>-Footnote-25007388
Ref: Documentation<54>-Footnote-35007453
Ref: Documentation<54>-Footnote-45007518
Ref: Documentation<54>-Footnote-55007583
Ref: Documentation<54>-Footnote-65007648
Ref: Documentation<54>-Footnote-75007713
Ref: Documentation<54>-Footnote-85007778
Ref: Documentation<54>-Footnote-95007843
Ref: Documentation<54>-Footnote-105007908
Ref: Documentation<54>-Footnote-115007974
Ref: Documentation<54>-Footnote-125008040
Ref: Documentation<54>-Footnote-135008106
Ref: Documentation<54>-Footnote-145008172
Ref: Documentation<54>-Footnote-155008238
Ref: Documentation<54>-Footnote-165008304
Ref: Documentation<54>-Footnote-175008370
Ref: Documentation<54>-Footnote-185008436
Ref: Documentation<54>-Footnote-195008502
Ref: Documentation<54>-Footnote-205008568
Ref: Documentation<54>-Footnote-215008634
Ref: Documentation<54>-Footnote-225008700
Ref: Documentation<54>-Footnote-235008766
Ref: Documentation<54>-Footnote-245008809
Ref: Documentation<54>-Footnote-255008875
Ref: Documentation<54>-Footnote-265008941
Ref: Documentation<54>-Footnote-275009007
Ref: Documentation<54>-Footnote-285009073
Ref: Documentation<54>-Footnote-295009139
Ref: Documentation<54>-Footnote-305009182
Ref: Documentation<54>-Footnote-315009248
Ref: Documentation<54>-Footnote-325009314
Ref: Documentation<54>-Footnote-335009380
Ref: Documentation<54>-Footnote-345009446
Ref: Documentation<54>-Footnote-355009512
Ref: Documentation<54>-Footnote-365009578
Ref: Documentation<54>-Footnote-375009644
Ref: Documentation<54>-Footnote-385009710
Ref: Documentation<54>-Footnote-395009776
Ref: Documentation<54>-Footnote-405009842
Ref: Documentation<54>-Footnote-415009908
Ref: Documentation<54>-Footnote-425009974
Ref: Documentation<54>-Footnote-435010040
Ref: Documentation<54>-Footnote-445010106
Ref: Documentation<54>-Footnote-455010172
Ref: Documentation<54>-Footnote-465010238
Ref: Documentation<54>-Footnote-475010304
Ref: Documentation<54>-Footnote-485010370
Ref: Documentation<54>-Footnote-495010436
Ref: Documentation<54>-Footnote-505010502
Ref: Documentation<54>-Footnote-515010567
Ref: Documentation<54>-Footnote-525010633
Ref: Documentation<54>-Footnote-535010699
Ref: Documentation<54>-Footnote-545010765
Ref: Documentation<54>-Footnote-555010831
Ref: Documentation<54>-Footnote-565010897
Ref: Documentation<54>-Footnote-575010962
Ref: Documentation<54>-Footnote-585011028
Ref: Documentation<54>-Footnote-595011094
Node: Tests<56>5011160
Ref: whatsnew/changelog id6925011270
Ref: 1bda5011270
Ref: Tests<56>-Footnote-15018896
Ref: Tests<56>-Footnote-25018961
Ref: Tests<56>-Footnote-35019026
Ref: Tests<56>-Footnote-45019091
Ref: Tests<56>-Footnote-55019156
Ref: Tests<56>-Footnote-65019221
Ref: Tests<56>-Footnote-75019286
Ref: Tests<56>-Footnote-85019351
Ref: Tests<56>-Footnote-95019416
Ref: Tests<56>-Footnote-105019481
Ref: Tests<56>-Footnote-115019547
Ref: Tests<56>-Footnote-125019613
Ref: Tests<56>-Footnote-135019679
Ref: Tests<56>-Footnote-145019745
Ref: Tests<56>-Footnote-155019811
Ref: Tests<56>-Footnote-165019877
Ref: Tests<56>-Footnote-175019943
Ref: Tests<56>-Footnote-185020009
Ref: Tests<56>-Footnote-195020075
Ref: Tests<56>-Footnote-205020141
Ref: Tests<56>-Footnote-215020207
Ref: Tests<56>-Footnote-225020273
Ref: Tests<56>-Footnote-235020339
Ref: Tests<56>-Footnote-245020405
Ref: Tests<56>-Footnote-255020471
Ref: Tests<56>-Footnote-265020537
Ref: Tests<56>-Footnote-275020603
Ref: Tests<56>-Footnote-285020669
Ref: Tests<56>-Footnote-295020735
Ref: Tests<56>-Footnote-305020801
Ref: Tests<56>-Footnote-315020867
Ref: Tests<56>-Footnote-325020933
Ref: Tests<56>-Footnote-335020999
Ref: Tests<56>-Footnote-345021065
Ref: Tests<56>-Footnote-355021131
Ref: Tests<56>-Footnote-365021197
Ref: Tests<56>-Footnote-375021263
Ref: Tests<56>-Footnote-385021329
Ref: Tests<56>-Footnote-395021395
Ref: Tests<56>-Footnote-405021461
Ref: Tests<56>-Footnote-415021527
Ref: Tests<56>-Footnote-425021593
Ref: Tests<56>-Footnote-435021659
Ref: Tests<56>-Footnote-445021725
Ref: Tests<56>-Footnote-455021791
Ref: Tests<56>-Footnote-465021857
Ref: Tests<56>-Footnote-475021923
Ref: Tests<56>-Footnote-485021989
Node: Build<60>5022055
Ref: whatsnew/changelog id6935022159
Ref: 1bdb5022159
Ref: Build<60>-Footnote-15027287
Ref: Build<60>-Footnote-25027352
Ref: Build<60>-Footnote-35027417
Ref: Build<60>-Footnote-45027482
Ref: Build<60>-Footnote-55027547
Ref: Build<60>-Footnote-65027612
Ref: Build<60>-Footnote-75027677
Ref: Build<60>-Footnote-85027742
Ref: Build<60>-Footnote-95027807
Ref: Build<60>-Footnote-105027872
Ref: Build<60>-Footnote-115027938
Ref: Build<60>-Footnote-125028004
Ref: Build<60>-Footnote-135028070
Ref: Build<60>-Footnote-145028136
Ref: Build<60>-Footnote-155028202
Ref: Build<60>-Footnote-165028268
Ref: Build<60>-Footnote-175028334
Ref: Build<60>-Footnote-185028400
Ref: Build<60>-Footnote-195028466
Ref: Build<60>-Footnote-205028532
Ref: Build<60>-Footnote-215028598
Ref: Build<60>-Footnote-225028664
Ref: Build<60>-Footnote-235028730
Ref: Build<60>-Footnote-245028795
Ref: Build<60>-Footnote-255028861
Ref: Build<60>-Footnote-265028927
Ref: Build<60>-Footnote-275028993
Ref: Build<60>-Footnote-285029059
Ref: Build<60>-Footnote-295029125
Ref: Build<60>-Footnote-305029191
Ref: Build<60>-Footnote-315029257
Ref: Build<60>-Footnote-325029323
Ref: Build<60>-Footnote-335029389
Ref: Build<60>-Footnote-345029455
Ref: Build<60>-Footnote-355029521
Ref: Build<60>-Footnote-365029587
Ref: Build<60>-Footnote-375029653
Node: Windows<53>5029719
Ref: whatsnew/changelog id6945029823
Ref: 1bdd5029823
Ref: Windows<53>-Footnote-15034246
Ref: Windows<53>-Footnote-25034311
Ref: Windows<53>-Footnote-35034376
Ref: Windows<53>-Footnote-45034441
Ref: Windows<53>-Footnote-55034506
Ref: Windows<53>-Footnote-65034571
Ref: Windows<53>-Footnote-75034636
Ref: Windows<53>-Footnote-85034701
Ref: Windows<53>-Footnote-95034766
Ref: Windows<53>-Footnote-105034831
Ref: Windows<53>-Footnote-115034897
Ref: Windows<53>-Footnote-125034963
Ref: Windows<53>-Footnote-135035029
Ref: Windows<53>-Footnote-145035095
Ref: Windows<53>-Footnote-155035161
Ref: Windows<53>-Footnote-165035227
Ref: Windows<53>-Footnote-175035293
Ref: Windows<53>-Footnote-185035359
Ref: Windows<53>-Footnote-195035425
Ref: Windows<53>-Footnote-205035491
Ref: Windows<53>-Footnote-215035557
Ref: Windows<53>-Footnote-225035623
Ref: Windows<53>-Footnote-235035689
Ref: Windows<53>-Footnote-245035755
Ref: Windows<53>-Footnote-255035821
Ref: Windows<53>-Footnote-265035887
Ref: Windows<53>-Footnote-275035953
Ref: Windows<53>-Footnote-285036019
Ref: Windows<53>-Footnote-295036085
Ref: Windows<53>-Footnote-305036151
Ref: Windows<53>-Footnote-315036217
Ref: Windows<53>-Footnote-325036283
Ref: Windows<53>-Footnote-335036349
Ref: Windows<53>-Footnote-345036415
Ref: Windows<53>-Footnote-355036481
Ref: Windows<53>-Footnote-365036547
Ref: Windows<53>-Footnote-375036613
Ref: Windows<53>-Footnote-385036679
Ref: Windows<53>-Footnote-395036745
Ref: Windows<53>-Footnote-405036811
Node: macOS<42>5036876
Ref: whatsnew/changelog id6955036979
Ref: 1bde5036979
Ref: macOS<42>-Footnote-15038586
Ref: macOS<42>-Footnote-25038651
Ref: macOS<42>-Footnote-35038716
Ref: macOS<42>-Footnote-45038781
Ref: macOS<42>-Footnote-55038846
Ref: macOS<42>-Footnote-65038911
Ref: macOS<42>-Footnote-75038976
Ref: macOS<42>-Footnote-85039041
Ref: macOS<42>-Footnote-95039106
Ref: macOS<42>-Footnote-105039171
Node: IDLE<41>5039237
Ref: whatsnew/changelog id6965039344
Ref: 1bdf5039344
Ref: IDLE<41>-Footnote-15047807
Ref: IDLE<41>-Footnote-25047872
Ref: IDLE<41>-Footnote-35047937
Ref: IDLE<41>-Footnote-45048002
Ref: IDLE<41>-Footnote-55048067
Ref: IDLE<41>-Footnote-65048132
Ref: IDLE<41>-Footnote-75048197
Ref: IDLE<41>-Footnote-85048262
Ref: IDLE<41>-Footnote-95048327
Ref: IDLE<41>-Footnote-105048392
Ref: IDLE<41>-Footnote-115048458
Ref: IDLE<41>-Footnote-125048524
Ref: IDLE<41>-Footnote-135048590
Ref: IDLE<41>-Footnote-145048656
Ref: IDLE<41>-Footnote-155048722
Ref: IDLE<41>-Footnote-165048788
Ref: IDLE<41>-Footnote-175048854
Ref: IDLE<41>-Footnote-185048920
Ref: IDLE<41>-Footnote-195048986
Ref: IDLE<41>-Footnote-205049052
Ref: IDLE<41>-Footnote-215049118
Ref: IDLE<41>-Footnote-225049184
Ref: IDLE<41>-Footnote-235049250
Ref: IDLE<41>-Footnote-245049316
Ref: IDLE<41>-Footnote-255049382
Ref: IDLE<41>-Footnote-265049448
Ref: IDLE<41>-Footnote-275049514
Ref: IDLE<41>-Footnote-285049582
Ref: IDLE<41>-Footnote-295049648
Ref: IDLE<41>-Footnote-305049714
Ref: IDLE<41>-Footnote-315049780
Ref: IDLE<41>-Footnote-325049846
Ref: IDLE<41>-Footnote-335049912
Ref: IDLE<41>-Footnote-345049978
Ref: IDLE<41>-Footnote-355050044
Ref: IDLE<41>-Footnote-365050110
Ref: IDLE<41>-Footnote-375050176
Ref: IDLE<41>-Footnote-385050242
Ref: IDLE<41>-Footnote-395050308
Ref: IDLE<41>-Footnote-405050374
Ref: IDLE<41>-Footnote-415050440
Ref: IDLE<41>-Footnote-425050506
Ref: IDLE<41>-Footnote-435050572
Ref: IDLE<41>-Footnote-445050638
Ref: IDLE<41>-Footnote-455050704
Ref: IDLE<41>-Footnote-465050770
Ref: IDLE<41>-Footnote-475050836
Ref: IDLE<41>-Footnote-485050902
Ref: IDLE<41>-Footnote-495050968
Ref: IDLE<41>-Footnote-505051034
Ref: IDLE<41>-Footnote-515051100
Ref: IDLE<41>-Footnote-525051166
Ref: IDLE<41>-Footnote-535051232
Ref: IDLE<41>-Footnote-545051298
Ref: IDLE<41>-Footnote-555051364
Ref: IDLE<41>-Footnote-565051430
Ref: IDLE<41>-Footnote-575051496
Ref: IDLE<41>-Footnote-585051562
Ref: IDLE<41>-Footnote-595051628
Node: Tools/Demos<30>5051694
Ref: whatsnew/changelog id6975051801
Ref: 1be05051801
Ref: Tools/Demos<30>-Footnote-15053450
Ref: Tools/Demos<30>-Footnote-25053515
Ref: Tools/Demos<30>-Footnote-35053580
Ref: Tools/Demos<30>-Footnote-45053645
Ref: Tools/Demos<30>-Footnote-55053710
Ref: Tools/Demos<30>-Footnote-65053775
Ref: Tools/Demos<30>-Footnote-75053840
Ref: Tools/Demos<30>-Footnote-85053905
Ref: Tools/Demos<30>-Footnote-95053970
Ref: Tools/Demos<30>-Footnote-105054035
Ref: Tools/Demos<30>-Footnote-115054101
Ref: Tools/Demos<30>-Footnote-125054167
Node: C API<55>5054233
Ref: whatsnew/changelog id6985054323
Ref: 1be15054323
Ref: C API<55>-Footnote-15057756
Ref: C API<55>-Footnote-25057821
Ref: C API<55>-Footnote-35057886
Ref: C API<55>-Footnote-45057951
Ref: C API<55>-Footnote-55058016
Ref: C API<55>-Footnote-65058081
Ref: C API<55>-Footnote-75058146
Ref: C API<55>-Footnote-85058211
Ref: C API<55>-Footnote-95058276
Ref: C API<55>-Footnote-105058341
Ref: C API<55>-Footnote-115058407
Ref: C API<55>-Footnote-125058473
Ref: C API<55>-Footnote-135058539
Ref: C API<55>-Footnote-145058605
Ref: C API<55>-Footnote-155058671
Ref: C API<55>-Footnote-165058737
Ref: C API<55>-Footnote-175058803
Ref: C API<55>-Footnote-185058869
Ref: C API<55>-Footnote-195058935
Ref: C API<55>-Footnote-205059001
Ref: C API<55>-Footnote-215059067
Ref: C API<55>-Footnote-225059133
Node: Python 3 7 0 final5059199
Ref: whatsnew/changelog python-3-7-0-final5059333
Ref: 1bea5059333
Node: Library<139>5059471
Ref: whatsnew/changelog id6995059556
Ref: 1beb5059556
Ref: Library<139>-Footnote-15059726
Node: C API<56>5059791
Ref: whatsnew/changelog id7005059876
Ref: 1bed5059876
Ref: C API<56>-Footnote-15060087
Node: Python 3 7 0 release candidate 15060152
Ref: whatsnew/changelog python-3-7-0-release-candidate-15060285
Ref: 1bee5060285
Node: Core and Builtins<137>5060574
Ref: whatsnew/changelog id7015060686
Ref: 1bef5060686
Ref: Core and Builtins<137>-Footnote-15061330
Ref: Core and Builtins<137>-Footnote-25061395
Ref: Core and Builtins<137>-Footnote-35061460
Ref: Core and Builtins<137>-Footnote-45061525
Node: Library<140>5061590
Ref: whatsnew/changelog id7025061728
Ref: 1bf05061728
Ref: Library<140>-Footnote-15063426
Ref: Library<140>-Footnote-25063491
Ref: Library<140>-Footnote-35063556
Ref: Library<140>-Footnote-45063621
Ref: Library<140>-Footnote-55063686
Ref: Library<140>-Footnote-65063751
Ref: Library<140>-Footnote-75063816
Ref: Library<140>-Footnote-85063881
Ref: Library<140>-Footnote-95063946
Ref: Library<140>-Footnote-105064011
Ref: Library<140>-Footnote-115064077
Ref: Library<140>-Footnote-125064143
Ref: Library<140>-Footnote-135064209
Node: Documentation<55>5064275
Ref: whatsnew/changelog id7035064400
Ref: 1bf15064400
Ref: Documentation<55>-Footnote-15064907
Ref: Documentation<55>-Footnote-25064972
Ref: Documentation<55>-Footnote-35065014
Ref: Documentation<55>-Footnote-45065079
Node: Build<61>5065144
Ref: whatsnew/changelog id7045065268
Ref: 1bf25065268
Ref: Build<61>-Footnote-15065530
Node: Windows<54>5065594
Ref: whatsnew/changelog id7055065709
Ref: 1bf35065709
Ref: Windows<54>-Footnote-15065866
Node: IDLE<42>5065931
Ref: whatsnew/changelog id7065066028
Ref: 1bf45066028
Ref: IDLE<42>-Footnote-15067248
Ref: IDLE<42>-Footnote-25067313
Ref: IDLE<42>-Footnote-35067378
Ref: IDLE<42>-Footnote-45067443
Ref: IDLE<42>-Footnote-55067508
Ref: IDLE<42>-Footnote-65067573
Node: Python 3 7 0 beta 55067638
Ref: whatsnew/changelog python-3-7-0-beta-55067772
Ref: 1bf55067772
Node: Core and Builtins<138>5068051
Ref: whatsnew/changelog id7075068150
Ref: 1bf65068150
Ref: Core and Builtins<138>-Footnote-15069664
Ref: Core and Builtins<138>-Footnote-25069729
Ref: Core and Builtins<138>-Footnote-35069794
Ref: Core and Builtins<138>-Footnote-45069859
Ref: Core and Builtins<138>-Footnote-55069924
Ref: Core and Builtins<138>-Footnote-65069989
Ref: Core and Builtins<138>-Footnote-75070054
Ref: Core and Builtins<138>-Footnote-85070119
Ref: Core and Builtins<138>-Footnote-95070184
Node: Library<141>5070249
Ref: whatsnew/changelog id7085070374
Ref: 1bf75070374
Ref: Library<141>-Footnote-15076004
Ref: Library<141>-Footnote-25076069
Ref: Library<141>-Footnote-35076134
Ref: Library<141>-Footnote-45076199
Ref: Library<141>-Footnote-55076264
Ref: Library<141>-Footnote-65076329
Ref: Library<141>-Footnote-75076394
Ref: Library<141>-Footnote-85076459
Ref: Library<141>-Footnote-95076524
Ref: Library<141>-Footnote-105076589
Ref: Library<141>-Footnote-115076655
Ref: Library<141>-Footnote-125076721
Ref: Library<141>-Footnote-135076787
Ref: Library<141>-Footnote-145076853
Ref: Library<141>-Footnote-155076919
Ref: Library<141>-Footnote-165076985
Ref: Library<141>-Footnote-175077051
Ref: Library<141>-Footnote-185077117
Ref: Library<141>-Footnote-195077183
Ref: Library<141>-Footnote-205077249
Ref: Library<141>-Footnote-215077315
Ref: Library<141>-Footnote-225077381
Ref: Library<141>-Footnote-235077447
Ref: Library<141>-Footnote-245077513
Ref: Library<141>-Footnote-255077579
Ref: Library<141>-Footnote-265077645
Ref: Library<141>-Footnote-275077711
Ref: Library<141>-Footnote-285077777
Ref: Library<141>-Footnote-295077843
Ref: Library<141>-Footnote-305077909
Ref: Library<141>-Footnote-315077975
Ref: Library<141>-Footnote-325078041
Ref: Library<141>-Footnote-335078107
Ref: Library<141>-Footnote-345078173
Ref: Library<141>-Footnote-355078239
Ref: Library<141>-Footnote-365078305
Ref: Library<141>-Footnote-375078371
Ref: Library<141>-Footnote-385078437
Node: Documentation<56>5078503
Ref: whatsnew/changelog id7095078615
Ref: 1bf85078615
Ref: Documentation<56>-Footnote-15079085
Ref: Documentation<56>-Footnote-25079150
Ref: Documentation<56>-Footnote-35079215
Ref: Documentation<56>-Footnote-45079257
Ref: Documentation<56>-Footnote-55079322
Ref: Documentation<56>-Footnote-65079387
Node: Tests<57>5079452
Ref: whatsnew/changelog id7105079561
Ref: 1bf95079561
Ref: Tests<57>-Footnote-15079910
Ref: Tests<57>-Footnote-25079975
Node: Build<62>5080040
Ref: whatsnew/changelog id7115080141
Ref: 1bfa5080141
Ref: Build<62>-Footnote-15080620
Ref: Build<62>-Footnote-25080685
Ref: Build<62>-Footnote-35080750
Node: macOS<43>5080815
Ref: whatsnew/changelog id7125080915
Ref: 1bfb5080915
Ref: macOS<43>-Footnote-15081157
Node: IDLE<43>5081222
Ref: whatsnew/changelog id7135081304
Ref: 1bfc5081304
Ref: IDLE<43>-Footnote-15081583
Ref: IDLE<43>-Footnote-25081648
Ref: IDLE<43>-Footnote-35081713
Node: Python 3 7 0 beta 45081778
Ref: whatsnew/changelog python-3-7-0-beta-45081899
Ref: 1bfd5081899
Node: Core and Builtins<139>5082234
Ref: whatsnew/changelog id7145082333
Ref: 1bfe5082333
Ref: Core and Builtins<139>-Footnote-15083467
Ref: Core and Builtins<139>-Footnote-25083532
Ref: Core and Builtins<139>-Footnote-35083597
Ref: Core and Builtins<139>-Footnote-45083662
Ref: Core and Builtins<139>-Footnote-55083727
Ref: Core and Builtins<139>-Footnote-65083792
Ref: Core and Builtins<139>-Footnote-75083857
Node: Library<142>5083922
Ref: whatsnew/changelog id7155084047
Ref: 1bff5084047
Ref: Library<142>-Footnote-15086884
Ref: Library<142>-Footnote-25086949
Ref: Library<142>-Footnote-35087014
Ref: Library<142>-Footnote-45087079
Ref: Library<142>-Footnote-55087145
Ref: Library<142>-Footnote-65087210
Ref: Library<142>-Footnote-75087275
Ref: Library<142>-Footnote-85087340
Ref: Library<142>-Footnote-95087405
Ref: Library<142>-Footnote-105087470
Ref: Library<142>-Footnote-115087536
Ref: Library<142>-Footnote-125087602
Ref: Library<142>-Footnote-135087668
Ref: Library<142>-Footnote-145087734
Ref: Library<142>-Footnote-155087800
Ref: Library<142>-Footnote-165087866
Ref: Library<142>-Footnote-175087932
Ref: Library<142>-Footnote-185087975
Ref: Library<142>-Footnote-195088041
Ref: Library<142>-Footnote-205088107
Ref: Library<142>-Footnote-215088173
Ref: Library<142>-Footnote-225088239
Node: Documentation<57>5088305
Ref: whatsnew/changelog id7165088417
Ref: 1c005088417
Ref: Documentation<57>-Footnote-15089168
Ref: Documentation<57>-Footnote-25089233
Ref: Documentation<57>-Footnote-35089298
Ref: Documentation<57>-Footnote-45089363
Ref: Documentation<57>-Footnote-55089428
Ref: Documentation<57>-Footnote-65089492
Node: Tests<58>5089557
Ref: whatsnew/changelog id7175089666
Ref: 1c015089666
Ref: Tests<58>-Footnote-15089882
Node: Build<63>5089947
Ref: whatsnew/changelog id7185090050
Ref: 1c025090050
Ref: Build<63>-Footnote-15090740
Ref: Build<63>-Footnote-25090805
Ref: Build<63>-Footnote-35090870
Ref: Build<63>-Footnote-45090935
Ref: Build<63>-Footnote-55091000
Node: Windows<55>5091065
Ref: whatsnew/changelog id7195091168
Ref: 1c035091168
Ref: Windows<55>-Footnote-15091309
Node: macOS<44>5091374
Ref: whatsnew/changelog id7205091476
Ref: 1c045091476
Ref: macOS<44>-Footnote-15091617
Node: IDLE<44>5091682
Ref: whatsnew/changelog id7215091788
Ref: 1c055091788
Ref: IDLE<44>-Footnote-15092378
Ref: IDLE<44>-Footnote-25092443
Node: Tools/Demos<31>5092508
Ref: whatsnew/changelog id7225092596
Ref: 1c065092596
Ref: Tools/Demos<31>-Footnote-15093204
Ref: Tools/Demos<31>-Footnote-25093269
Ref: Tools/Demos<31>-Footnote-35093334
Ref: Tools/Demos<31>-Footnote-45093399
Node: Python 3 7 0 beta 35093464
Ref: whatsnew/changelog python-3-7-0-beta-35093585
Ref: 1c075093585
Node: Security<44>5093966
Ref: whatsnew/changelog id7235094065
Ref: 1c085094065
Ref: Security<44>-Footnote-15094697
Ref: Security<44>-Footnote-25094762
Ref: Security<44>-Footnote-35094817
Ref: Security<44>-Footnote-45094882
Ref: Security<44>-Footnote-55094947
Ref: Security<44>-Footnote-65095002
Node: Core and Builtins<140>5095057
Ref: whatsnew/changelog id7245095177
Ref: 1c095095177
Ref: Core and Builtins<140>-Footnote-15096387
Ref: Core and Builtins<140>-Footnote-25096452
Ref: Core and Builtins<140>-Footnote-35096517
Ref: Core and Builtins<140>-Footnote-45096582
Ref: Core and Builtins<140>-Footnote-55096647
Ref: Core and Builtins<140>-Footnote-65096712
Ref: Core and Builtins<140>-Footnote-75096777
Node: Library<143>5096842
Ref: whatsnew/changelog id7255096967
Ref: 1c0a5096967
Ref: Library<143>-Footnote-15101022
Ref: Library<143>-Footnote-25101087
Ref: Library<143>-Footnote-35101152
Ref: Library<143>-Footnote-45101217
Ref: Library<143>-Footnote-55101282
Ref: Library<143>-Footnote-65101347
Ref: Library<143>-Footnote-75101412
Ref: Library<143>-Footnote-85101477
Ref: Library<143>-Footnote-95101542
Ref: Library<143>-Footnote-105101607
Ref: Library<143>-Footnote-115101673
Ref: Library<143>-Footnote-125101739
Ref: Library<143>-Footnote-135101805
Ref: Library<143>-Footnote-145101871
Ref: Library<143>-Footnote-155101937
Ref: Library<143>-Footnote-165102003
Ref: Library<143>-Footnote-175102069
Ref: Library<143>-Footnote-185102135
Ref: Library<143>-Footnote-195102201
Ref: Library<143>-Footnote-205102267
Ref: Library<143>-Footnote-215102333
Ref: Library<143>-Footnote-225102399
Ref: Library<143>-Footnote-235102465
Ref: Library<143>-Footnote-245102531
Ref: Library<143>-Footnote-255102597
Ref: Library<143>-Footnote-265102663
Ref: Library<143>-Footnote-275102729
Node: Documentation<58>5102795
Ref: whatsnew/changelog id7265102907
Ref: 1c0b5102907
Ref: Documentation<58>-Footnote-15103544
Ref: Documentation<58>-Footnote-25103609
Ref: Documentation<58>-Footnote-35103674
Ref: Documentation<58>-Footnote-45103739
Ref: Documentation<58>-Footnote-55103804
Node: Tests<59>5103869
Ref: whatsnew/changelog id7275103978
Ref: 1c0c5103978
Ref: Tests<59>-Footnote-15104311
Ref: Tests<59>-Footnote-25104376
Ref: Tests<59>-Footnote-35104441
Node: Build<64>5104506
Ref: whatsnew/changelog id7285104609
Ref: 1c0d5104609
Ref: Build<64>-Footnote-15104746
Node: Windows<56>5104811
Ref: whatsnew/changelog id7295104914
Ref: 1c0e5104914
Ref: Windows<56>-Footnote-15105193
Ref: Windows<56>-Footnote-25105258
Node: macOS<45>5105323
Ref: whatsnew/changelog id7305105425
Ref: 1c0f5105425
Ref: macOS<45>-Footnote-15105857
Node: IDLE<45>5105922
Ref: whatsnew/changelog id7315106028
Ref: 1c105106028
Ref: IDLE<45>-Footnote-15106743
Ref: IDLE<45>-Footnote-25106808
Node: Tools/Demos<32>5106873
Ref: whatsnew/changelog id7325106979
Ref: 1c115106979
Ref: Tools/Demos<32>-Footnote-15107209
Node: C API<57>5107274
Ref: whatsnew/changelog id7335107363
Ref: 1c125107363
Ref: C API<57>-Footnote-15107747
Ref: C API<57>-Footnote-25107812
Node: Python 3 7 0 beta 25107877
Ref: whatsnew/changelog python-3-7-0-beta-25107998
Ref: 1c135107998
Node: Security<45>5108359
Ref: whatsnew/changelog id7345108458
Ref: 1c145108458
Ref: Security<45>-Footnote-15108643
Node: Core and Builtins<141>5108708
Ref: whatsnew/changelog id7355108828
Ref: 1c155108828
Ref: Core and Builtins<141>-Footnote-15109659
Ref: Core and Builtins<141>-Footnote-25109724
Ref: Core and Builtins<141>-Footnote-35109789
Ref: Core and Builtins<141>-Footnote-45109854
Ref: Core and Builtins<141>-Footnote-55109919
Ref: Core and Builtins<141>-Footnote-65109984
Ref: Core and Builtins<141>-Footnote-75110049
Node: Library<144>5110114
Ref: whatsnew/changelog id7365110239
Ref: 1c165110239
Ref: Library<144>-Footnote-15116674
Ref: Library<144>-Footnote-25116739
Ref: Library<144>-Footnote-35116804
Ref: Library<144>-Footnote-45116869
Ref: Library<144>-Footnote-55116934
Ref: Library<144>-Footnote-65116999
Ref: Library<144>-Footnote-75117064
Ref: Library<144>-Footnote-85117129
Ref: Library<144>-Footnote-95117194
Ref: Library<144>-Footnote-105117259
Ref: Library<144>-Footnote-115117325
Ref: Library<144>-Footnote-125117391
Ref: Library<144>-Footnote-135117457
Ref: Library<144>-Footnote-145117523
Ref: Library<144>-Footnote-155117589
Ref: Library<144>-Footnote-165117655
Ref: Library<144>-Footnote-175117721
Ref: Library<144>-Footnote-185117787
Ref: Library<144>-Footnote-195117853
Ref: Library<144>-Footnote-205117919
Ref: Library<144>-Footnote-215117985
Ref: Library<144>-Footnote-225118051
Ref: Library<144>-Footnote-235118117
Ref: Library<144>-Footnote-245118183
Ref: Library<144>-Footnote-255118249
Ref: Library<144>-Footnote-265118315
Ref: Library<144>-Footnote-275118381
Ref: Library<144>-Footnote-285118447
Ref: Library<144>-Footnote-295118513
Ref: Library<144>-Footnote-305118579
Ref: Library<144>-Footnote-315118645
Ref: Library<144>-Footnote-325118711
Ref: Library<144>-Footnote-335118777
Ref: Library<144>-Footnote-345118843
Node: Documentation<59>5118909
Ref: whatsnew/changelog id7375119021
Ref: 1c175119021
Ref: Documentation<59>-Footnote-15119972
Ref: Documentation<59>-Footnote-25120037
Ref: Documentation<59>-Footnote-35120102
Ref: Documentation<59>-Footnote-45120167
Ref: Documentation<59>-Footnote-55120232
Ref: Documentation<59>-Footnote-65120297
Ref: Documentation<59>-Footnote-75120361
Ref: Documentation<59>-Footnote-85120426
Node: Tests<60>5120491
Ref: whatsnew/changelog id7385120600
Ref: 1c185120600
Ref: Tests<60>-Footnote-15120743
Node: Build<65>5120808
Ref: whatsnew/changelog id7395120911
Ref: 1c195120911
Ref: Build<65>-Footnote-15121052
Node: Windows<57>5121117
Ref: whatsnew/changelog id7405121220
Ref: 1c1a5121220
Ref: Windows<57>-Footnote-15121956
Ref: Windows<57>-Footnote-25122021
Ref: Windows<57>-Footnote-35122086
Ref: Windows<57>-Footnote-45122151
Ref: Windows<57>-Footnote-55122216
Ref: Windows<57>-Footnote-65122281
Node: macOS<46>5122346
Ref: whatsnew/changelog id7415122448
Ref: 1c1b5122448
Ref: macOS<46>-Footnote-15122583
Node: IDLE<46>5122648
Ref: whatsnew/changelog id7425122754
Ref: 1c1c5122754
Ref: IDLE<46>-Footnote-15123601
Ref: IDLE<46>-Footnote-25123666
Ref: IDLE<46>-Footnote-35123731
Ref: IDLE<46>-Footnote-45123796
Ref: IDLE<46>-Footnote-55123861
Ref: IDLE<46>-Footnote-65123926
Node: Tools/Demos<33>5123991
Ref: whatsnew/changelog id7435124079
Ref: 1c1d5124079
Ref: Tools/Demos<33>-Footnote-15124298
Node: Python 3 7 0 beta 15124363
Ref: whatsnew/changelog python-3-7-0-beta-15124485
Ref: 1c1e5124485
Node: Core and Builtins<142>5124790
Ref: whatsnew/changelog id7445124889
Ref: 1c1f5124889
Ref: Core and Builtins<142>-Footnote-15128323
Ref: Core and Builtins<142>-Footnote-25128388
Ref: Core and Builtins<142>-Footnote-35128453
Ref: Core and Builtins<142>-Footnote-45128518
Ref: Core and Builtins<142>-Footnote-55128583
Ref: Core and Builtins<142>-Footnote-65128648
Ref: Core and Builtins<142>-Footnote-75128713
Ref: Core and Builtins<142>-Footnote-85128778
Ref: Core and Builtins<142>-Footnote-95128843
Ref: Core and Builtins<142>-Footnote-105128885
Ref: Core and Builtins<142>-Footnote-115128951
Ref: Core and Builtins<142>-Footnote-125129017
Ref: Core and Builtins<142>-Footnote-135129083
Ref: Core and Builtins<142>-Footnote-145129149
Ref: Core and Builtins<142>-Footnote-155129215
Ref: Core and Builtins<142>-Footnote-165129281
Ref: Core and Builtins<142>-Footnote-175129347
Ref: Core and Builtins<142>-Footnote-185129413
Ref: Core and Builtins<142>-Footnote-195129456
Ref: Core and Builtins<142>-Footnote-205129522
Ref: Core and Builtins<142>-Footnote-215129588
Ref: Core and Builtins<142>-Footnote-225129654
Ref: Core and Builtins<142>-Footnote-235129720
Node: Library<145>5129786
Ref: whatsnew/changelog id7455129911
Ref: 1c205129911
Ref: Library<145>-Footnote-15137275
Ref: Library<145>-Footnote-25137340
Ref: Library<145>-Footnote-35137405
Ref: Library<145>-Footnote-45137470
Ref: Library<145>-Footnote-55137535
Ref: Library<145>-Footnote-65137600
Ref: Library<145>-Footnote-75137665
Ref: Library<145>-Footnote-85137730
Ref: Library<145>-Footnote-95137795
Ref: Library<145>-Footnote-105137860
Ref: Library<145>-Footnote-115137926
Ref: Library<145>-Footnote-125137992
Ref: Library<145>-Footnote-135138058
Ref: Library<145>-Footnote-145138124
Ref: Library<145>-Footnote-155138190
Ref: Library<145>-Footnote-165138256
Ref: Library<145>-Footnote-175138322
Ref: Library<145>-Footnote-185138388
Ref: Library<145>-Footnote-195138431
Ref: Library<145>-Footnote-205138497
Ref: Library<145>-Footnote-215138563
Ref: Library<145>-Footnote-225138629
Ref: Library<145>-Footnote-235138695
Ref: Library<145>-Footnote-245138761
Ref: Library<145>-Footnote-255138827
Ref: Library<145>-Footnote-265138893
Ref: Library<145>-Footnote-275138959
Ref: Library<145>-Footnote-285139025
Ref: Library<145>-Footnote-295139091
Ref: Library<145>-Footnote-305139157
Ref: Library<145>-Footnote-315139223
Ref: Library<145>-Footnote-325139289
Ref: Library<145>-Footnote-335139355
Ref: Library<145>-Footnote-345139421
Ref: Library<145>-Footnote-355139487
Ref: Library<145>-Footnote-365139553
Ref: Library<145>-Footnote-375139619
Ref: Library<145>-Footnote-385139685
Ref: Library<145>-Footnote-395139751
Ref: Library<145>-Footnote-405139817
Ref: Library<145>-Footnote-415139883
Ref: Library<145>-Footnote-425139949
Ref: Library<145>-Footnote-435140015
Ref: Library<145>-Footnote-445140081
Ref: Library<145>-Footnote-455140147
Ref: Library<145>-Footnote-465140213
Ref: Library<145>-Footnote-475140279
Node: Documentation<60>5140345
Ref: whatsnew/changelog id7465140457
Ref: 1c215140457
Ref: Documentation<60>-Footnote-15140998
Ref: Documentation<60>-Footnote-25141063
Ref: Documentation<60>-Footnote-35141128
Node: Tests<61>5141193
Ref: whatsnew/changelog id7475141302
Ref: 1c225141302
Ref: Tests<61>-Footnote-15142214
Ref: Tests<61>-Footnote-25142279
Ref: Tests<61>-Footnote-35142344
Ref: Tests<61>-Footnote-45142409
Ref: Tests<61>-Footnote-55142474
Ref: Tests<61>-Footnote-65142539
Node: Build<66>5142604
Ref: whatsnew/changelog id7485142707
Ref: 1c235142707
Ref: Build<66>-Footnote-15143310
Ref: Build<66>-Footnote-25143375
Ref: Build<66>-Footnote-35143440
Ref: Build<66>-Footnote-45143505
Node: Windows<58>5143570
Ref: whatsnew/changelog id7495143673
Ref: 1c245143673
Ref: Windows<58>-Footnote-15144054
Ref: Windows<58>-Footnote-25144119
Ref: Windows<58>-Footnote-35144184
Node: macOS<47>5144249
Ref: whatsnew/changelog id7505144352
Ref: 1c255144352
Ref: macOS<47>-Footnote-15144874
Ref: macOS<47>-Footnote-25144939
Node: C API<58>5145004
Ref: whatsnew/changelog id7515145087
Ref: 1c265145087
Ref: C API<58>-Footnote-15145408
Ref: C API<58>-Footnote-25145473
Node: Python 3 7 0 alpha 45145538
Ref: whatsnew/changelog python-3-7-0-alpha-45145661
Ref: 1c275145661
Node: Core and Builtins<143>5145960
Ref: whatsnew/changelog id7525146060
Ref: 1c285146060
Ref: Core and Builtins<143>-Footnote-15149567
Ref: Core and Builtins<143>-Footnote-25149632
Ref: Core and Builtins<143>-Footnote-35149697
Ref: Core and Builtins<143>-Footnote-45149762
Ref: Core and Builtins<143>-Footnote-55149827
Ref: Core and Builtins<143>-Footnote-65149892
Ref: Core and Builtins<143>-Footnote-75149957
Ref: Core and Builtins<143>-Footnote-85150022
Ref: Core and Builtins<143>-Footnote-95150087
Ref: Core and Builtins<143>-Footnote-105150152
Ref: Core and Builtins<143>-Footnote-115150218
Ref: Core and Builtins<143>-Footnote-125150284
Ref: Core and Builtins<143>-Footnote-135150350
Ref: Core and Builtins<143>-Footnote-145150416
Ref: Core and Builtins<143>-Footnote-155150482
Ref: Core and Builtins<143>-Footnote-165150548
Ref: Core and Builtins<143>-Footnote-175150614
Ref: Core and Builtins<143>-Footnote-185150680
Ref: Core and Builtins<143>-Footnote-195150746
Ref: Core and Builtins<143>-Footnote-205150789
Ref: Core and Builtins<143>-Footnote-215150855
Ref: Core and Builtins<143>-Footnote-225150898
Ref: Core and Builtins<143>-Footnote-235150964
Ref: Core and Builtins<143>-Footnote-245151007
Ref: Core and Builtins<143>-Footnote-255151073
Ref: Core and Builtins<143>-Footnote-265151139
Ref: Core and Builtins<143>-Footnote-275151182
Node: Library<146>5151248
Ref: whatsnew/changelog id7535151374
Ref: 1c2a5151374
Ref: Library<146>-Footnote-15159392
Ref: Library<146>-Footnote-25159457
Ref: Library<146>-Footnote-35159522
Ref: Library<146>-Footnote-45159587
Ref: Library<146>-Footnote-55159652
Ref: Library<146>-Footnote-65159717
Ref: Library<146>-Footnote-75159782
Ref: Library<146>-Footnote-85159847
Ref: Library<146>-Footnote-95159912
Ref: Library<146>-Footnote-105159977
Ref: Library<146>-Footnote-115160043
Ref: Library<146>-Footnote-125160109
Ref: Library<146>-Footnote-135160175
Ref: Library<146>-Footnote-145160241
Ref: Library<146>-Footnote-155160307
Ref: Library<146>-Footnote-165160373
Ref: Library<146>-Footnote-175160439
Ref: Library<146>-Footnote-185160505
Ref: Library<146>-Footnote-195160571
Ref: Library<146>-Footnote-205160637
Ref: Library<146>-Footnote-215160703
Ref: Library<146>-Footnote-225160769
Ref: Library<146>-Footnote-235160835
Ref: Library<146>-Footnote-245160901
Ref: Library<146>-Footnote-255160967
Ref: Library<146>-Footnote-265161033
Ref: Library<146>-Footnote-275161099
Ref: Library<146>-Footnote-285161165
Ref: Library<146>-Footnote-295161231
Ref: Library<146>-Footnote-305161297
Ref: Library<146>-Footnote-315161363
Ref: Library<146>-Footnote-325161429
Ref: Library<146>-Footnote-335161495
Ref: Library<146>-Footnote-345161561
Ref: Library<146>-Footnote-355161627
Ref: Library<146>-Footnote-365161693
Ref: Library<146>-Footnote-375161759
Ref: Library<146>-Footnote-385161825
Ref: Library<146>-Footnote-395161891
Ref: Library<146>-Footnote-405161957
Ref: Library<146>-Footnote-415162023
Ref: Library<146>-Footnote-425162089
Ref: Library<146>-Footnote-435162155
Ref: Library<146>-Footnote-445162221
Ref: Library<146>-Footnote-455162287
Ref: Library<146>-Footnote-465162353
Ref: Library<146>-Footnote-475162419
Ref: Library<146>-Footnote-485162485
Ref: Library<146>-Footnote-495162551
Ref: Library<146>-Footnote-505162617
Ref: Library<146>-Footnote-515162683
Ref: Library<146>-Footnote-525162749
Ref: Library<146>-Footnote-535162815
Ref: Library<146>-Footnote-545162881
Node: Documentation<61>5162947
Ref: whatsnew/changelog id7545163060
Ref: 1c2b5163060
Ref: Documentation<61>-Footnote-15163230
Node: Tests<62>5163295
Ref: whatsnew/changelog id7555163407
Ref: 1c2c5163407
Ref: Tests<62>-Footnote-15163802
Ref: Tests<62>-Footnote-25163867
Node: Windows<59>5163932
Ref: whatsnew/changelog id7565164042
Ref: 1c2d5164042
Ref: Windows<59>-Footnote-15164241
Node: Tools/Demos<34>5164306
Ref: whatsnew/changelog id7575164416
Ref: 1c2e5164416
Ref: Tools/Demos<34>-Footnote-15164698
Node: C API<59>5164763
Ref: whatsnew/changelog id7585164853
Ref: 1c2f5164853
Ref: C API<59>-Footnote-15165497
Ref: C API<59>-Footnote-25165562
Ref: C API<59>-Footnote-35165627
Ref: C API<59>-Footnote-45165692
Node: Python 3 7 0 alpha 35165757
Ref: whatsnew/changelog python-3-7-0-alpha-35165881
Ref: 1c305165881
Node: Core and Builtins<144>5166238
Ref: whatsnew/changelog id7595166338
Ref: 1c315166338
Ref: Core and Builtins<144>-Footnote-15171473
Ref: Core and Builtins<144>-Footnote-25171538
Ref: Core and Builtins<144>-Footnote-35171603
Ref: Core and Builtins<144>-Footnote-45171668
Ref: Core and Builtins<144>-Footnote-55171733
Ref: Core and Builtins<144>-Footnote-65171798
Ref: Core and Builtins<144>-Footnote-75171863
Ref: Core and Builtins<144>-Footnote-85171928
Ref: Core and Builtins<144>-Footnote-95171993
Ref: Core and Builtins<144>-Footnote-105172058
Ref: Core and Builtins<144>-Footnote-115172124
Ref: Core and Builtins<144>-Footnote-125172190
Ref: Core and Builtins<144>-Footnote-135172256
Ref: Core and Builtins<144>-Footnote-145172322
Ref: Core and Builtins<144>-Footnote-155172388
Ref: Core and Builtins<144>-Footnote-165172454
Ref: Core and Builtins<144>-Footnote-175172520
Ref: Core and Builtins<144>-Footnote-185172586
Ref: Core and Builtins<144>-Footnote-195172652
Ref: Core and Builtins<144>-Footnote-205172718
Ref: Core and Builtins<144>-Footnote-215172784
Ref: Core and Builtins<144>-Footnote-225172850
Node: Library<147>5172916
Ref: whatsnew/changelog id7605173042
Ref: 1c325173042
Ref: Library<147>-Footnote-15189098
Ref: Library<147>-Footnote-25189163
Ref: Library<147>-Footnote-35189228
Ref: Library<147>-Footnote-45189293
Ref: Library<147>-Footnote-55189358
Ref: Library<147>-Footnote-65189423
Ref: Library<147>-Footnote-75189488
Ref: Library<147>-Footnote-85189553
Ref: Library<147>-Footnote-95189618
Ref: Library<147>-Footnote-105189683
Ref: Library<147>-Footnote-115189749
Ref: Library<147>-Footnote-125189815
Ref: Library<147>-Footnote-135189881
Ref: Library<147>-Footnote-145189947
Ref: Library<147>-Footnote-155190013
Ref: Library<147>-Footnote-165190079
Ref: Library<147>-Footnote-175190145
Ref: Library<147>-Footnote-185190211
Ref: Library<147>-Footnote-195190277
Ref: Library<147>-Footnote-205190343
Ref: Library<147>-Footnote-215190409
Ref: Library<147>-Footnote-225190475
Ref: Library<147>-Footnote-235190541
Ref: Library<147>-Footnote-245190607
Ref: Library<147>-Footnote-255190673
Ref: Library<147>-Footnote-265190741
Ref: Library<147>-Footnote-275190807
Ref: Library<147>-Footnote-285190873
Ref: Library<147>-Footnote-295190939
Ref: Library<147>-Footnote-305191005
Ref: Library<147>-Footnote-315191071
Ref: Library<147>-Footnote-325191137
Ref: Library<147>-Footnote-335191180
Ref: Library<147>-Footnote-345191246
Ref: Library<147>-Footnote-355191312
Ref: Library<147>-Footnote-365191378
Ref: Library<147>-Footnote-375191444
Ref: Library<147>-Footnote-385191510
Ref: Library<147>-Footnote-395191576
Ref: Library<147>-Footnote-405191642
Ref: Library<147>-Footnote-415191708
Ref: Library<147>-Footnote-425191774
Ref: Library<147>-Footnote-435191840
Ref: Library<147>-Footnote-445191906
Ref: Library<147>-Footnote-455191972
Ref: Library<147>-Footnote-465192038
Ref: Library<147>-Footnote-475192103
Ref: Library<147>-Footnote-485192169
Ref: Library<147>-Footnote-495192235
Ref: Library<147>-Footnote-505192301
Ref: Library<147>-Footnote-515192367
Ref: Library<147>-Footnote-525192433
Ref: Library<147>-Footnote-535192499
Ref: Library<147>-Footnote-545192565
Ref: Library<147>-Footnote-555192631
Ref: Library<147>-Footnote-565192697
Ref: Library<147>-Footnote-575192763
Ref: Library<147>-Footnote-585192829
Ref: Library<147>-Footnote-595192895
Ref: Library<147>-Footnote-605192961
Ref: Library<147>-Footnote-615193027
Ref: Library<147>-Footnote-625193093
Ref: Library<147>-Footnote-635193136
Ref: Library<147>-Footnote-645193202
Ref: Library<147>-Footnote-655193268
Ref: Library<147>-Footnote-665193334
Ref: Library<147>-Footnote-675193400
Ref: Library<147>-Footnote-685193466
Ref: Library<147>-Footnote-695193532
Ref: Library<147>-Footnote-705193598
Ref: Library<147>-Footnote-715193664
Ref: Library<147>-Footnote-725193730
Ref: Library<147>-Footnote-735193796
Ref: Library<147>-Footnote-745193862
Ref: Library<147>-Footnote-755193928
Ref: Library<147>-Footnote-765193994
Ref: Library<147>-Footnote-775194060
Ref: Library<147>-Footnote-785194126
Ref: Library<147>-Footnote-795194192
Ref: Library<147>-Footnote-805194258
Ref: Library<147>-Footnote-815194324
Ref: Library<147>-Footnote-825194390
Ref: Library<147>-Footnote-835194433
Ref: Library<147>-Footnote-845194499
Ref: Library<147>-Footnote-855194565
Ref: Library<147>-Footnote-865194631
Ref: Library<147>-Footnote-875194697
Ref: Library<147>-Footnote-885194763
Ref: Library<147>-Footnote-895194829
Ref: Library<147>-Footnote-905194895
Ref: Library<147>-Footnote-915194961
Ref: Library<147>-Footnote-925195027
Ref: Library<147>-Footnote-935195093
Ref: Library<147>-Footnote-945195159
Ref: Library<147>-Footnote-955195225
Ref: Library<147>-Footnote-965195291
Ref: Library<147>-Footnote-975195357
Ref: Library<147>-Footnote-985195423
Node: Documentation<62>5195489
Ref: whatsnew/changelog id7615195602
Ref: 1c375195602
Ref: Documentation<62>-Footnote-15195785
Node: Tests<63>5195850
Ref: whatsnew/changelog id7625195960
Ref: 1c385195960
Ref: Tests<63>-Footnote-15197170
Ref: Tests<63>-Footnote-25197235
Ref: Tests<63>-Footnote-35197300
Ref: Tests<63>-Footnote-45197365
Ref: Tests<63>-Footnote-55197430
Ref: Tests<63>-Footnote-65197495
Ref: Tests<63>-Footnote-75197560
Node: Build<67>5197625
Ref: whatsnew/changelog id7635197729
Ref: 1c395197729
Ref: Build<67>-Footnote-15198943
Ref: Build<67>-Footnote-25199008
Ref: Build<67>-Footnote-35199073
Ref: Build<67>-Footnote-45199138
Ref: Build<67>-Footnote-55199203
Ref: Build<67>-Footnote-65199268
Ref: Build<67>-Footnote-75199333
Ref: Build<67>-Footnote-85199398
Ref: Build<67>-Footnote-95199463
Ref: Build<67>-Footnote-105199528
Ref: Build<67>-Footnote-115199594
Ref: Build<67>-Footnote-125199660
Node: Windows<60>5199726
Ref: whatsnew/changelog id7645199830
Ref: 1c3a5199830
Ref: Windows<60>-Footnote-15200363
Ref: Windows<60>-Footnote-25200427
Ref: Windows<60>-Footnote-35200492
Ref: Windows<60>-Footnote-45200557
Node: macOS<48>5200622
Ref: whatsnew/changelog id7655200725
Ref: 1c3b5200725
Ref: macOS<48>-Footnote-15200859
Node: IDLE<47>5200924
Ref: whatsnew/changelog id7665201031
Ref: 1c3c5201031
Ref: IDLE<47>-Footnote-15203124
Ref: IDLE<47>-Footnote-25203189
Ref: IDLE<47>-Footnote-35203254
Ref: IDLE<47>-Footnote-45203319
Ref: IDLE<47>-Footnote-55203384
Ref: IDLE<47>-Footnote-65203449
Ref: IDLE<47>-Footnote-75203514
Ref: IDLE<47>-Footnote-85203579
Node: Tools/Demos<35>5203644
Ref: whatsnew/changelog id7675203751
Ref: 1c3d5203751
Ref: Tools/Demos<35>-Footnote-15204283
Ref: Tools/Demos<35>-Footnote-25204348
Node: C API<60>5204413
Ref: whatsnew/changelog id7685204503
Ref: 1c3e5204503
Ref: C API<60>-Footnote-15205631
Ref: C API<60>-Footnote-25205696
Ref: C API<60>-Footnote-35205761
Ref: C API<60>-Footnote-45205826
Ref: C API<60>-Footnote-55205891
Ref: C API<60>-Footnote-65205956
Node: Python 3 7 0 alpha 25206021
Ref: whatsnew/changelog python-3-7-0-alpha-25206145
Ref: 1c3f5206145
Node: Core and Builtins<145>5206406
Ref: whatsnew/changelog id7695206506
Ref: 1c405206506
Ref: Core and Builtins<145>-Footnote-15210699
Ref: Core and Builtins<145>-Footnote-25210764
Ref: Core and Builtins<145>-Footnote-35210829
Ref: Core and Builtins<145>-Footnote-45210894
Ref: Core and Builtins<145>-Footnote-55210959
Ref: Core and Builtins<145>-Footnote-65211024
Ref: Core and Builtins<145>-Footnote-75211089
Ref: Core and Builtins<145>-Footnote-85211154
Ref: Core and Builtins<145>-Footnote-95211219
Ref: Core and Builtins<145>-Footnote-105211284
Ref: Core and Builtins<145>-Footnote-115211350
Ref: Core and Builtins<145>-Footnote-125211416
Ref: Core and Builtins<145>-Footnote-135211482
Ref: Core and Builtins<145>-Footnote-145211548
Ref: Core and Builtins<145>-Footnote-155211614
Ref: Core and Builtins<145>-Footnote-165211680
Ref: Core and Builtins<145>-Footnote-175211746
Ref: Core and Builtins<145>-Footnote-185211812
Ref: Core and Builtins<145>-Footnote-195211878
Ref: Core and Builtins<145>-Footnote-205211944
Ref: Core and Builtins<145>-Footnote-215211987
Ref: Core and Builtins<145>-Footnote-225212053
Ref: Core and Builtins<145>-Footnote-235212119
Ref: Core and Builtins<145>-Footnote-245212185
Ref: Core and Builtins<145>-Footnote-255212251
Ref: Core and Builtins<145>-Footnote-265212317
Ref: Core and Builtins<145>-Footnote-275212383
Node: Library<148>5212426
Ref: whatsnew/changelog id7705212552
Ref: 1c415212552
Ref: Library<148>-Footnote-15216608
Ref: Library<148>-Footnote-25216673
Ref: Library<148>-Footnote-35216738
Ref: Library<148>-Footnote-45216803
Ref: Library<148>-Footnote-55216868
Ref: Library<148>-Footnote-65216933
Ref: Library<148>-Footnote-75216998
Ref: Library<148>-Footnote-85217063
Ref: Library<148>-Footnote-95217128
Ref: Library<148>-Footnote-105217193
Ref: Library<148>-Footnote-115217259
Ref: Library<148>-Footnote-125217325
Ref: Library<148>-Footnote-135217391
Ref: Library<148>-Footnote-145217457
Ref: Library<148>-Footnote-155217523
Ref: Library<148>-Footnote-165217589
Ref: Library<148>-Footnote-175217655
Ref: Library<148>-Footnote-185217721
Ref: Library<148>-Footnote-195217787
Ref: Library<148>-Footnote-205217853
Ref: Library<148>-Footnote-215217919
Ref: Library<148>-Footnote-225217985
Ref: Library<148>-Footnote-235218051
Ref: Library<148>-Footnote-245218117
Ref: Library<148>-Footnote-255218183
Ref: Library<148>-Footnote-265218249
Node: Documentation<63>5218315
Ref: whatsnew/changelog id7715218428
Ref: 1c425218428
Ref: Documentation<63>-Footnote-15218819
Ref: Documentation<63>-Footnote-25218884
Node: Build<68>5218949
Ref: whatsnew/changelog id7725219058
Ref: 1c435219058
Ref: Build<68>-Footnote-15219685
Ref: Build<68>-Footnote-25219750
Ref: Build<68>-Footnote-35219815
Ref: Build<68>-Footnote-45219880
Ref: Build<68>-Footnote-55219945
Ref: Build<68>-Footnote-65220010
Node: IDLE<48>5220075
Ref: whatsnew/changelog id7735220176
Ref: 1c445220176
Ref: IDLE<48>-Footnote-15221482
Ref: IDLE<48>-Footnote-25221547
Ref: IDLE<48>-Footnote-35221612
Ref: IDLE<48>-Footnote-45221677
Ref: IDLE<48>-Footnote-55221742
Ref: IDLE<48>-Footnote-65221807
Node: C API<61>5221874
Ref: whatsnew/changelog id7745221957
Ref: 1c455221957
Ref: C API<61>-Footnote-15222681
Ref: C API<61>-Footnote-25222746
Ref: C API<61>-Footnote-35222811
Ref: C API<61>-Footnote-45222876
Node: Python 3 7 0 alpha 15222918
Ref: whatsnew/changelog python-3-7-0-alpha-15223040
Ref: 1c465223040
Node: Security<46>5223403
Ref: whatsnew/changelog id7755223503
Ref: 1c475223503
Ref: Security<46>-Footnote-15225157
Ref: Security<46>-Footnote-25225222
Ref: Security<46>-Footnote-35225287
Ref: Security<46>-Footnote-45225352
Ref: Security<46>-Footnote-55225417
Ref: Security<46>-Footnote-65225482
Ref: Security<46>-Footnote-75225537
Ref: Security<46>-Footnote-85225592
Ref: Security<46>-Footnote-95225647
Ref: Security<46>-Footnote-105225702
Ref: Security<46>-Footnote-115225758
Ref: Security<46>-Footnote-125225814
Ref: Security<46>-Footnote-135225880
Ref: Security<46>-Footnote-145225946
Ref: Security<46>-Footnote-155226002
Node: Core and Builtins<146>5226058
Ref: whatsnew/changelog id7765226179
Ref: 1c485226179
Ref: Core and Builtins<146>-Footnote-15247083
Ref: Core and Builtins<146>-Footnote-25247148
Ref: Core and Builtins<146>-Footnote-35247213
Ref: Core and Builtins<146>-Footnote-45247278
Ref: Core and Builtins<146>-Footnote-55247343
Ref: Core and Builtins<146>-Footnote-65247408
Ref: Core and Builtins<146>-Footnote-75247473
Ref: Core and Builtins<146>-Footnote-85247538
Ref: Core and Builtins<146>-Footnote-95247603
Ref: Core and Builtins<146>-Footnote-105247668
Ref: Core and Builtins<146>-Footnote-115247734
Ref: Core and Builtins<146>-Footnote-125247800
Ref: Core and Builtins<146>-Footnote-135247866
Ref: Core and Builtins<146>-Footnote-145247932
Ref: Core and Builtins<146>-Footnote-155247998
Ref: Core and Builtins<146>-Footnote-165248064
Ref: Core and Builtins<146>-Footnote-175248130
Ref: Core and Builtins<146>-Footnote-185248196
Ref: Core and Builtins<146>-Footnote-195248262
Ref: Core and Builtins<146>-Footnote-205248328
Ref: Core and Builtins<146>-Footnote-215248394
Ref: Core and Builtins<146>-Footnote-225248460
Ref: Core and Builtins<146>-Footnote-235248526
Ref: Core and Builtins<146>-Footnote-245248592
Ref: Core and Builtins<146>-Footnote-255248658
Ref: Core and Builtins<146>-Footnote-265248724
Ref: Core and Builtins<146>-Footnote-275248790
Ref: Core and Builtins<146>-Footnote-285248856
Ref: Core and Builtins<146>-Footnote-295248922
Ref: Core and Builtins<146>-Footnote-305248988
Ref: Core and Builtins<146>-Footnote-315249054
Ref: Core and Builtins<146>-Footnote-325249120
Ref: Core and Builtins<146>-Footnote-335249186
Ref: Core and Builtins<146>-Footnote-345249252
Ref: Core and Builtins<146>-Footnote-355249318
Ref: Core and Builtins<146>-Footnote-365249361
Ref: Core and Builtins<146>-Footnote-375249427
Ref: Core and Builtins<146>-Footnote-385249493
Ref: Core and Builtins<146>-Footnote-395249559
Ref: Core and Builtins<146>-Footnote-405249625
Ref: Core and Builtins<146>-Footnote-415249691
Ref: Core and Builtins<146>-Footnote-425249757
Ref: Core and Builtins<146>-Footnote-435249823
Ref: Core and Builtins<146>-Footnote-445249889
Ref: Core and Builtins<146>-Footnote-455249955
Ref: Core and Builtins<146>-Footnote-465250021
Ref: Core and Builtins<146>-Footnote-475250087
Ref: Core and Builtins<146>-Footnote-485250153
Ref: Core and Builtins<146>-Footnote-495250219
Ref: Core and Builtins<146>-Footnote-505250285
Ref: Core and Builtins<146>-Footnote-515250351
Ref: Core and Builtins<146>-Footnote-525250417
Ref: Core and Builtins<146>-Footnote-535250483
Ref: Core and Builtins<146>-Footnote-545250549
Ref: Core and Builtins<146>-Footnote-555250615
Ref: Core and Builtins<146>-Footnote-565250681
Ref: Core and Builtins<146>-Footnote-575250747
Ref: Core and Builtins<146>-Footnote-585250813
Ref: Core and Builtins<146>-Footnote-595250879
Ref: Core and Builtins<146>-Footnote-605250945
Ref: Core and Builtins<146>-Footnote-615251011
Ref: Core and Builtins<146>-Footnote-625251077
Ref: Core and Builtins<146>-Footnote-635251143
Ref: Core and Builtins<146>-Footnote-645251209
Ref: Core and Builtins<146>-Footnote-655251275
Ref: Core and Builtins<146>-Footnote-665251341
Ref: Core and Builtins<146>-Footnote-675251407
Ref: Core and Builtins<146>-Footnote-685251473
Ref: Core and Builtins<146>-Footnote-695251539
Ref: Core and Builtins<146>-Footnote-705251605
Ref: Core and Builtins<146>-Footnote-715251671
Ref: Core and Builtins<146>-Footnote-725251737
Ref: Core and Builtins<146>-Footnote-735251803
Ref: Core and Builtins<146>-Footnote-745251869
Ref: Core and Builtins<146>-Footnote-755251935
Ref: Core and Builtins<146>-Footnote-765252001
Ref: Core and Builtins<146>-Footnote-775252067
Ref: Core and Builtins<146>-Footnote-785252133
Ref: Core and Builtins<146>-Footnote-795252199
Ref: Core and Builtins<146>-Footnote-805252265
Ref: Core and Builtins<146>-Footnote-815252331
Ref: Core and Builtins<146>-Footnote-825252397
Ref: Core and Builtins<146>-Footnote-835252463
Ref: Core and Builtins<146>-Footnote-845252529
Ref: Core and Builtins<146>-Footnote-855252595
Ref: Core and Builtins<146>-Footnote-865252661
Ref: Core and Builtins<146>-Footnote-875252727
Ref: Core and Builtins<146>-Footnote-885252793
Ref: Core and Builtins<146>-Footnote-895252859
Ref: Core and Builtins<146>-Footnote-905252925
Ref: Core and Builtins<146>-Footnote-915252968
Ref: Core and Builtins<146>-Footnote-925253034
Ref: Core and Builtins<146>-Footnote-935253100
Ref: Core and Builtins<146>-Footnote-945253166
Ref: Core and Builtins<146>-Footnote-955253232
Ref: Core and Builtins<146>-Footnote-965253298
Ref: Core and Builtins<146>-Footnote-975253364
Ref: Core and Builtins<146>-Footnote-985253430
Ref: Core and Builtins<146>-Footnote-995253496
Ref: Core and Builtins<146>-Footnote-1005253562
Ref: Core and Builtins<146>-Footnote-1015253629
Ref: Core and Builtins<146>-Footnote-1025253696
Ref: Core and Builtins<146>-Footnote-1035253763
Ref: Core and Builtins<146>-Footnote-1045253830
Ref: Core and Builtins<146>-Footnote-1055253897
Ref: Core and Builtins<146>-Footnote-1065253964
Ref: Core and Builtins<146>-Footnote-1075254031
Ref: Core and Builtins<146>-Footnote-1085254098
Ref: Core and Builtins<146>-Footnote-1095254165
Ref: Core and Builtins<146>-Footnote-1105254232
Ref: Core and Builtins<146>-Footnote-1115254299
Ref: Core and Builtins<146>-Footnote-1125254366
Ref: Core and Builtins<146>-Footnote-1135254433
Ref: Core and Builtins<146>-Footnote-1145254500
Ref: Core and Builtins<146>-Footnote-1155254567
Ref: Core and Builtins<146>-Footnote-1165254634
Ref: Core and Builtins<146>-Footnote-1175254701
Ref: Core and Builtins<146>-Footnote-1185254768
Ref: Core and Builtins<146>-Footnote-1195254835
Ref: Core and Builtins<146>-Footnote-1205254902
Ref: Core and Builtins<146>-Footnote-1215254969
Ref: Core and Builtins<146>-Footnote-1225255036
Ref: Core and Builtins<146>-Footnote-1235255103
Ref: Core and Builtins<146>-Footnote-1245255170
Ref: Core and Builtins<146>-Footnote-1255255237
Ref: Core and Builtins<146>-Footnote-1265255304
Ref: Core and Builtins<146>-Footnote-1275255371
Ref: Core and Builtins<146>-Footnote-1285255438
Ref: Core and Builtins<146>-Footnote-1295255505
Ref: Core and Builtins<146>-Footnote-1305255572
Ref: Core and Builtins<146>-Footnote-1315255639
Ref: Core and Builtins<146>-Footnote-1325255706
Ref: Core and Builtins<146>-Footnote-1335255773
Ref: Core and Builtins<146>-Footnote-1345255840
Ref: Core and Builtins<146>-Footnote-1355255907
Ref: Core and Builtins<146>-Footnote-1365255974
Ref: Core and Builtins<146>-Footnote-1375256041
Ref: Core and Builtins<146>-Footnote-1385256108
Ref: Core and Builtins<146>-Footnote-1395256175
Ref: Core and Builtins<146>-Footnote-1405256242
Ref: Core and Builtins<146>-Footnote-1415256309
Ref: Core and Builtins<146>-Footnote-1425256376
Ref: Core and Builtins<146>-Footnote-1435256443
Ref: Core and Builtins<146>-Footnote-1445256510
Ref: Core and Builtins<146>-Footnote-1455256577
Ref: Core and Builtins<146>-Footnote-1465256644
Ref: Core and Builtins<146>-Footnote-1475256711
Ref: Core and Builtins<146>-Footnote-1485256778
Node: Library<149>5256845
Ref: whatsnew/changelog id7775256971
Ref: 1c495256971
Ref: Library<149>-Footnote-15303627
Ref: Library<149>-Footnote-25303692
Ref: Library<149>-Footnote-35303757
Ref: Library<149>-Footnote-45303822
Ref: Library<149>-Footnote-55303887
Ref: Library<149>-Footnote-65303952
Ref: Library<149>-Footnote-75304017
Ref: Library<149>-Footnote-85304082
Ref: Library<149>-Footnote-95304147
Ref: Library<149>-Footnote-105304212
Ref: Library<149>-Footnote-115304278
Ref: Library<149>-Footnote-125304344
Ref: Library<149>-Footnote-135304410
Ref: Library<149>-Footnote-145304476
Ref: Library<149>-Footnote-155304542
Ref: Library<149>-Footnote-165304608
Ref: Library<149>-Footnote-175304674
Ref: Library<149>-Footnote-185304740
Ref: Library<149>-Footnote-195304806
Ref: Library<149>-Footnote-205304872
Ref: Library<149>-Footnote-215304938
Ref: Library<149>-Footnote-225305006
Ref: Library<149>-Footnote-235305072
Ref: Library<149>-Footnote-245305138
Ref: Library<149>-Footnote-255305204
Ref: Library<149>-Footnote-265305270
Ref: Library<149>-Footnote-275305313
Ref: Library<149>-Footnote-285305379
Ref: Library<149>-Footnote-295305445
Ref: Library<149>-Footnote-305305511
Ref: Library<149>-Footnote-315305577
Ref: Library<149>-Footnote-325305643
Ref: Library<149>-Footnote-335305709
Ref: Library<149>-Footnote-345305775
Ref: Library<149>-Footnote-355305840
Ref: Library<149>-Footnote-365305906
Ref: Library<149>-Footnote-375305972
Ref: Library<149>-Footnote-385306038
Ref: Library<149>-Footnote-395306104
Ref: Library<149>-Footnote-405306169
Ref: Library<149>-Footnote-415306235
Ref: Library<149>-Footnote-425306301
Ref: Library<149>-Footnote-435306367
Ref: Library<149>-Footnote-445306433
Ref: Library<149>-Footnote-455306499
Ref: Library<149>-Footnote-465306565
Ref: Library<149>-Footnote-475306631
Ref: Library<149>-Footnote-485306697
Ref: Library<149>-Footnote-495306763
Ref: Library<149>-Footnote-505306829
Ref: Library<149>-Footnote-515306895
Ref: Library<149>-Footnote-525306961
Ref: Library<149>-Footnote-535307026
Ref: Library<149>-Footnote-545307092
Ref: Library<149>-Footnote-555307158
Ref: Library<149>-Footnote-565307224
Ref: Library<149>-Footnote-575307290
Ref: Library<149>-Footnote-585307356
Ref: Library<149>-Footnote-595307422
Ref: Library<149>-Footnote-605307488
Ref: Library<149>-Footnote-615307554
Ref: Library<149>-Footnote-625307620
Ref: Library<149>-Footnote-635307686
Ref: Library<149>-Footnote-645307752
Ref: Library<149>-Footnote-655307818
Ref: Library<149>-Footnote-665307884
Ref: Library<149>-Footnote-675307950
Ref: Library<149>-Footnote-685308016
Ref: Library<149>-Footnote-695308082
Ref: Library<149>-Footnote-705308148
Ref: Library<149>-Footnote-715308214
Ref: Library<149>-Footnote-725308280
Ref: Library<149>-Footnote-735308345
Ref: Library<149>-Footnote-745308411
Ref: Library<149>-Footnote-755308477
Ref: Library<149>-Footnote-765308543
Ref: Library<149>-Footnote-775308609
Ref: Library<149>-Footnote-785308675
Ref: Library<149>-Footnote-795308741
Ref: Library<149>-Footnote-805308807
Ref: Library<149>-Footnote-815308873
Ref: Library<149>-Footnote-825308939
Ref: Library<149>-Footnote-835309005
Ref: Library<149>-Footnote-845309071
Ref: Library<149>-Footnote-855309137
Ref: Library<149>-Footnote-865309203
Ref: Library<149>-Footnote-875309269
Ref: Library<149>-Footnote-885309335
Ref: Library<149>-Footnote-895309401
Ref: Library<149>-Footnote-905309467
Ref: Library<149>-Footnote-915309533
Ref: Library<149>-Footnote-925309599
Ref: Library<149>-Footnote-935309665
Ref: Library<149>-Footnote-945309731
Ref: Library<149>-Footnote-955309797
Ref: Library<149>-Footnote-965309863
Ref: Library<149>-Footnote-975309929
Ref: Library<149>-Footnote-985309995
Ref: Library<149>-Footnote-995310061
Ref: Library<149>-Footnote-1005310127
Ref: Library<149>-Footnote-1015310194
Ref: Library<149>-Footnote-1025310261
Ref: Library<149>-Footnote-1035310328
Ref: Library<149>-Footnote-1045310395
Ref: Library<149>-Footnote-1055310462
Ref: Library<149>-Footnote-1065310529
Ref: Library<149>-Footnote-1075310596
Ref: Library<149>-Footnote-1085310663
Ref: Library<149>-Footnote-1095310730
Ref: Library<149>-Footnote-1105310797
Ref: Library<149>-Footnote-1115310864
Ref: Library<149>-Footnote-1125310931
Ref: Library<149>-Footnote-1135310998
Ref: Library<149>-Footnote-1145311065
Ref: Library<149>-Footnote-1155311132
Ref: Library<149>-Footnote-1165311199
Ref: Library<149>-Footnote-1175311265
Ref: Library<149>-Footnote-1185311332
Ref: Library<149>-Footnote-1195311399
Ref: Library<149>-Footnote-1205311466
Ref: Library<149>-Footnote-1215311533
Ref: Library<149>-Footnote-1225311600
Ref: Library<149>-Footnote-1235311667
Ref: Library<149>-Footnote-1245311734
Ref: Library<149>-Footnote-1255311801
Ref: Library<149>-Footnote-1265311868
Ref: Library<149>-Footnote-1275311935
Ref: Library<149>-Footnote-1285312002
Ref: Library<149>-Footnote-1295312069
Ref: Library<149>-Footnote-1305312136
Ref: Library<149>-Footnote-1315312203
Ref: Library<149>-Footnote-1325312270
Ref: Library<149>-Footnote-1335312337
Ref: Library<149>-Footnote-1345312404
Ref: Library<149>-Footnote-1355312471
Ref: Library<149>-Footnote-1365312538
Ref: Library<149>-Footnote-1375312605
Ref: Library<149>-Footnote-1385312672
Ref: Library<149>-Footnote-1395312739
Ref: Library<149>-Footnote-1405312806
Ref: Library<149>-Footnote-1415312873
Ref: Library<149>-Footnote-1425312940
Ref: Library<149>-Footnote-1435313007
Ref: Library<149>-Footnote-1445313074
Ref: Library<149>-Footnote-1455313141
Ref: Library<149>-Footnote-1465313208
Ref: Library<149>-Footnote-1475313274
Ref: Library<149>-Footnote-1485313341
Ref: Library<149>-Footnote-1495313408
Ref: Library<149>-Footnote-1505313475
Ref: Library<149>-Footnote-1515313542
Ref: Library<149>-Footnote-1525313609
Ref: Library<149>-Footnote-1535313676
Ref: Library<149>-Footnote-1545313743
Ref: Library<149>-Footnote-1555313810
Ref: Library<149>-Footnote-1565313877
Ref: Library<149>-Footnote-1575313944
Ref: Library<149>-Footnote-1585314011
Ref: Library<149>-Footnote-1595314078
Ref: Library<149>-Footnote-1605314145
Ref: Library<149>-Footnote-1615314212
Ref: Library<149>-Footnote-1625314279
Ref: Library<149>-Footnote-1635314346
Ref: Library<149>-Footnote-1645314413
Ref: Library<149>-Footnote-1655314480
Ref: Library<149>-Footnote-1665314547
Ref: Library<149>-Footnote-1675314614
Ref: Library<149>-Footnote-1685314681
Ref: Library<149>-Footnote-1695314748
Ref: Library<149>-Footnote-1705314814
Ref: Library<149>-Footnote-1715314881
Ref: Library<149>-Footnote-1725314948
Ref: Library<149>-Footnote-1735315015
Ref: Library<149>-Footnote-1745315082
Ref: Library<149>-Footnote-1755315149
Ref: Library<149>-Footnote-1765315216
Ref: Library<149>-Footnote-1775315283
Ref: Library<149>-Footnote-1785315350
Ref: Library<149>-Footnote-1795315417
Ref: Library<149>-Footnote-1805315484
Ref: Library<149>-Footnote-1815315550
Ref: Library<149>-Footnote-1825315617
Ref: Library<149>-Footnote-1835315684
Ref: Library<149>-Footnote-1845315751
Ref: Library<149>-Footnote-1855315818
Ref: Library<149>-Footnote-1865315885
Ref: Library<149>-Footnote-1875315951
Ref: Library<149>-Footnote-1885316018
Ref: Library<149>-Footnote-1895316085
Ref: Library<149>-Footnote-1905316152
Ref: Library<149>-Footnote-1915316219
Ref: Library<149>-Footnote-1925316286
Ref: Library<149>-Footnote-1935316353
Ref: Library<149>-Footnote-1945316420
Ref: Library<149>-Footnote-1955316487
Ref: Library<149>-Footnote-1965316554
Ref: Library<149>-Footnote-1975316621
Ref: Library<149>-Footnote-1985316688
Ref: Library<149>-Footnote-1995316755
Ref: Library<149>-Footnote-2005316822
Ref: Library<149>-Footnote-2015316889
Ref: Library<149>-Footnote-2025316956
Ref: Library<149>-Footnote-2035317023
Ref: Library<149>-Footnote-2045317090
Ref: Library<149>-Footnote-2055317157
Ref: Library<149>-Footnote-2065317224
Ref: Library<149>-Footnote-2075317291
Ref: Library<149>-Footnote-2085317358
Ref: Library<149>-Footnote-2095317425
Ref: Library<149>-Footnote-2105317492
Ref: Library<149>-Footnote-2115317559
Ref: Library<149>-Footnote-2125317626
Ref: Library<149>-Footnote-2135317693
Ref: Library<149>-Footnote-2145317760
Ref: Library<149>-Footnote-2155317827
Ref: Library<149>-Footnote-2165317894
Ref: Library<149>-Footnote-2175317961
Ref: Library<149>-Footnote-2185318028
Ref: Library<149>-Footnote-2195318095
Ref: Library<149>-Footnote-2205318162
Ref: Library<149>-Footnote-2215318229
Ref: Library<149>-Footnote-2225318296
Ref: Library<149>-Footnote-2235318363
Ref: Library<149>-Footnote-2245318430
Ref: Library<149>-Footnote-2255318496
Ref: Library<149>-Footnote-2265318563
Ref: Library<149>-Footnote-2275318630
Ref: Library<149>-Footnote-2285318697
Ref: Library<149>-Footnote-2295318764
Ref: Library<149>-Footnote-2305318831
Ref: Library<149>-Footnote-2315318898
Ref: Library<149>-Footnote-2325318965
Ref: Library<149>-Footnote-2335319032
Ref: Library<149>-Footnote-2345319099
Ref: Library<149>-Footnote-2355319166
Ref: Library<149>-Footnote-2365319233
Ref: Library<149>-Footnote-2375319300
Ref: Library<149>-Footnote-2385319367
Ref: Library<149>-Footnote-2395319434
Ref: Library<149>-Footnote-2405319501
Ref: Library<149>-Footnote-2415319568
Ref: Library<149>-Footnote-2425319635
Ref: Library<149>-Footnote-2435319702
Ref: Library<149>-Footnote-2445319769
Ref: Library<149>-Footnote-2455319836
Ref: Library<149>-Footnote-2465319903
Ref: Library<149>-Footnote-2475319970
Ref: Library<149>-Footnote-2485320037
Ref: Library<149>-Footnote-2495320104
Ref: Library<149>-Footnote-2505320171
Ref: Library<149>-Footnote-2515320238
Ref: Library<149>-Footnote-2525320305
Ref: Library<149>-Footnote-2535320372
Ref: Library<149>-Footnote-2545320439
Ref: Library<149>-Footnote-2555320506
Ref: Library<149>-Footnote-2565320573
Ref: Library<149>-Footnote-2575320640
Ref: Library<149>-Footnote-2585320707
Ref: Library<149>-Footnote-2595320774
Ref: Library<149>-Footnote-2605320841
Ref: Library<149>-Footnote-2615320908
Ref: Library<149>-Footnote-2625320975
Ref: Library<149>-Footnote-2635321042
Ref: Library<149>-Footnote-2645321109
Ref: Library<149>-Footnote-2655321176
Ref: Library<149>-Footnote-2665321243
Ref: Library<149>-Footnote-2675321310
Ref: Library<149>-Footnote-2685321377
Ref: Library<149>-Footnote-2695321444
Ref: Library<149>-Footnote-2705321511
Ref: Library<149>-Footnote-2715321578
Ref: Library<149>-Footnote-2725321645
Ref: Library<149>-Footnote-2735321701
Ref: Library<149>-Footnote-2745321768
Ref: Library<149>-Footnote-2755321835
Ref: Library<149>-Footnote-2765321902
Ref: Library<149>-Footnote-2775321969
Ref: Library<149>-Footnote-2785322036
Ref: Library<149>-Footnote-2795322103
Ref: Library<149>-Footnote-2805322170
Ref: Library<149>-Footnote-2815322237
Ref: Library<149>-Footnote-2825322304
Ref: Library<149>-Footnote-2835322371
Ref: Library<149>-Footnote-2845322438
Ref: Library<149>-Footnote-2855322505
Ref: Library<149>-Footnote-2865322572
Ref: Library<149>-Footnote-2875322639
Ref: Library<149>-Footnote-2885322706
Ref: Library<149>-Footnote-2895322773
Ref: Library<149>-Footnote-2905322840
Ref: Library<149>-Footnote-2915322907
Ref: Library<149>-Footnote-2925322974
Ref: Library<149>-Footnote-2935323041
Ref: Library<149>-Footnote-2945323108
Ref: Library<149>-Footnote-2955323175
Ref: Library<149>-Footnote-2965323242
Ref: Library<149>-Footnote-2975323309
Ref: Library<149>-Footnote-2985323376
Ref: Library<149>-Footnote-2995323443
Ref: Library<149>-Footnote-3005323510
Ref: Library<149>-Footnote-3015323577
Ref: Library<149>-Footnote-3025323644
Ref: Library<149>-Footnote-3035323711
Ref: Library<149>-Footnote-3045323778
Ref: Library<149>-Footnote-3055323845
Ref: Library<149>-Footnote-3065323912
Ref: Library<149>-Footnote-3075323979
Ref: Library<149>-Footnote-3085324046
Ref: Library<149>-Footnote-3095324113
Ref: Library<149>-Footnote-3105324180
Ref: Library<149>-Footnote-3115324247
Ref: Library<149>-Footnote-3125324314
Ref: Library<149>-Footnote-3135324381
Ref: Library<149>-Footnote-3145324448
Ref: Library<149>-Footnote-3155324515
Ref: Library<149>-Footnote-3165324582
Ref: Library<149>-Footnote-3175324649
Ref: Library<149>-Footnote-3185324716
Ref: Library<149>-Footnote-3195324783
Ref: Library<149>-Footnote-3205324850
Ref: Library<149>-Footnote-3215324917
Ref: Library<149>-Footnote-3225324984
Ref: Library<149>-Footnote-3235325051
Ref: Library<149>-Footnote-3245325118
Ref: Library<149>-Footnote-3255325185
Ref: Library<149>-Footnote-3265325252
Node: Documentation<64>5325319
Ref: whatsnew/changelog id7785325432
Ref: 1c4a5325432
Ref: Documentation<64>-Footnote-15327598
Ref: Documentation<64>-Footnote-25327663
Ref: Documentation<64>-Footnote-35327728
Ref: Documentation<64>-Footnote-45327793
Ref: Documentation<64>-Footnote-55327858
Ref: Documentation<64>-Footnote-65327923
Ref: Documentation<64>-Footnote-75327988
Ref: Documentation<64>-Footnote-85328053
Ref: Documentation<64>-Footnote-95328118
Ref: Documentation<64>-Footnote-105328183
Ref: Documentation<64>-Footnote-115328249
Ref: Documentation<64>-Footnote-125328315
Ref: Documentation<64>-Footnote-135328381
Ref: Documentation<64>-Footnote-145328447
Ref: Documentation<64>-Footnote-155328513
Ref: Documentation<64>-Footnote-165328579
Ref: Documentation<64>-Footnote-175328622
Node: Tests<64>5328688
Ref: whatsnew/changelog id7795328798
Ref: 1c4d5328798
Ref: Tests<64>-Footnote-15331562
Ref: Tests<64>-Footnote-25331627
Ref: Tests<64>-Footnote-35331692
Ref: Tests<64>-Footnote-45331757
Ref: Tests<64>-Footnote-55331822
Ref: Tests<64>-Footnote-65331887
Ref: Tests<64>-Footnote-75331952
Ref: Tests<64>-Footnote-85332017
Ref: Tests<64>-Footnote-95332082
Ref: Tests<64>-Footnote-105332147
Ref: Tests<64>-Footnote-115332213
Ref: Tests<64>-Footnote-125332279
Ref: Tests<64>-Footnote-135332345
Ref: Tests<64>-Footnote-145332411
Ref: Tests<64>-Footnote-155332477
Ref: Tests<64>-Footnote-165332543
Ref: Tests<64>-Footnote-175332609
Ref: Tests<64>-Footnote-185332675
Ref: Tests<64>-Footnote-195332741
Node: Build<69>5332807
Ref: whatsnew/changelog id7805332911
Ref: 1c4e5332911
Ref: Build<69>-Footnote-15337680
Ref: Build<69>-Footnote-25337745
Ref: Build<69>-Footnote-35337810
Ref: Build<69>-Footnote-45337875
Ref: Build<69>-Footnote-55337917
Ref: Build<69>-Footnote-65337982
Ref: Build<69>-Footnote-75338047
Ref: Build<69>-Footnote-85338112
Ref: Build<69>-Footnote-95338177
Ref: Build<69>-Footnote-105338242
Ref: Build<69>-Footnote-115338308
Ref: Build<69>-Footnote-125338374
Ref: Build<69>-Footnote-135338440
Ref: Build<69>-Footnote-145338506
Ref: Build<69>-Footnote-155338572
Ref: Build<69>-Footnote-165338638
Ref: Build<69>-Footnote-175338704
Ref: Build<69>-Footnote-185338770
Ref: Build<69>-Footnote-195338836
Ref: Build<69>-Footnote-205338902
Ref: Build<69>-Footnote-215338968
Ref: Build<69>-Footnote-225339034
Ref: Build<69>-Footnote-235339100
Ref: Build<69>-Footnote-245339166
Ref: Build<69>-Footnote-255339232
Ref: Build<69>-Footnote-265339298
Ref: Build<69>-Footnote-275339364
Ref: Build<69>-Footnote-285339430
Ref: Build<69>-Footnote-295339496
Ref: Build<69>-Footnote-305339562
Ref: Build<69>-Footnote-315339628
Ref: Build<69>-Footnote-325339694
Ref: Build<69>-Footnote-335339760
Ref: Build<69>-Footnote-345339826
Ref: Build<69>-Footnote-355339892
Ref: Build<69>-Footnote-365339958
Ref: Build<69>-Footnote-375340024
Node: Windows<61>5340090
Ref: whatsnew/changelog id7815340193
Ref: 1c4f5340193
Ref: Windows<61>-Footnote-15342679
Ref: Windows<61>-Footnote-25342744
Ref: Windows<61>-Footnote-35342809
Ref: Windows<61>-Footnote-45342874
Ref: Windows<61>-Footnote-55342939
Ref: Windows<61>-Footnote-65343004
Ref: Windows<61>-Footnote-75343069
Ref: Windows<61>-Footnote-85343134
Ref: Windows<61>-Footnote-95343199
Ref: Windows<61>-Footnote-105343264
Ref: Windows<61>-Footnote-115343330
Ref: Windows<61>-Footnote-125343396
Ref: Windows<61>-Footnote-135343462
Ref: Windows<61>-Footnote-145343528
Ref: Windows<61>-Footnote-155343594
Ref: Windows<61>-Footnote-165343660
Ref: Windows<61>-Footnote-175343726
Ref: Windows<61>-Footnote-185343792
Ref: Windows<61>-Footnote-195343858
Ref: Windows<61>-Footnote-205343924
Ref: Windows<61>-Footnote-215343990
Ref: Windows<61>-Footnote-225344056
Ref: Windows<61>-Footnote-235344122
Ref: Windows<61>-Footnote-245344188
Ref: Windows<61>-Footnote-255344254
Node: IDLE<49>5344320
Ref: whatsnew/changelog id7825344429
Ref: 1c505344429
Ref: IDLE<49>-Footnote-15354430
Ref: IDLE<49>-Footnote-25354495
Ref: IDLE<49>-Footnote-35354560
Ref: IDLE<49>-Footnote-45354625
Ref: IDLE<49>-Footnote-55354690
Ref: IDLE<49>-Footnote-65354755
Ref: IDLE<49>-Footnote-75354820
Ref: IDLE<49>-Footnote-85354885
Ref: IDLE<49>-Footnote-95354950
Ref: IDLE<49>-Footnote-105355015
Ref: IDLE<49>-Footnote-115355081
Ref: IDLE<49>-Footnote-125355147
Ref: IDLE<49>-Footnote-135355213
Ref: IDLE<49>-Footnote-145355279
Ref: IDLE<49>-Footnote-155355345
Ref: IDLE<49>-Footnote-165355411
Ref: IDLE<49>-Footnote-175355477
Ref: IDLE<49>-Footnote-185355543
Ref: IDLE<49>-Footnote-195355609
Ref: IDLE<49>-Footnote-205355675
Ref: IDLE<49>-Footnote-215355741
Ref: IDLE<49>-Footnote-225355807
Ref: IDLE<49>-Footnote-235355873
Ref: IDLE<49>-Footnote-245355939
Ref: IDLE<49>-Footnote-255356005
Ref: IDLE<49>-Footnote-265356071
Ref: IDLE<49>-Footnote-275356137
Ref: IDLE<49>-Footnote-285356203
Ref: IDLE<49>-Footnote-295356269
Ref: IDLE<49>-Footnote-305356335
Ref: IDLE<49>-Footnote-315356401
Ref: IDLE<49>-Footnote-325356467
Ref: IDLE<49>-Footnote-335356533
Ref: IDLE<49>-Footnote-345356599
Ref: IDLE<49>-Footnote-355356664
Ref: IDLE<49>-Footnote-365356730
Ref: IDLE<49>-Footnote-375356796
Ref: IDLE<49>-Footnote-385356862
Ref: IDLE<49>-Footnote-395356928
Ref: IDLE<49>-Footnote-405356994
Ref: IDLE<49>-Footnote-415357060
Ref: IDLE<49>-Footnote-425357126
Ref: IDLE<49>-Footnote-435357192
Ref: IDLE<49>-Footnote-445357257
Ref: IDLE<49>-Footnote-455357323
Ref: IDLE<49>-Footnote-465357389
Ref: IDLE<49>-Footnote-475357455
Ref: IDLE<49>-Footnote-485357521
Ref: IDLE<49>-Footnote-495357587
Ref: IDLE<49>-Footnote-505357653
Ref: IDLE<49>-Footnote-515357719
Node: Tools/Demos<36>5357785
Ref: whatsnew/changelog id7835357892
Ref: 1c515357892
Ref: Tools/Demos<36>-Footnote-15359380
Ref: Tools/Demos<36>-Footnote-25359445
Ref: Tools/Demos<36>-Footnote-35359487
Ref: Tools/Demos<36>-Footnote-45359552
Ref: Tools/Demos<36>-Footnote-55359617
Ref: Tools/Demos<36>-Footnote-65359682
Ref: Tools/Demos<36>-Footnote-75359747
Ref: Tools/Demos<36>-Footnote-85359812
Node: C API<62>5359877
Ref: whatsnew/changelog id7845359967
Ref: 1c525359967
Ref: C API<62>-Footnote-15363031
Ref: C API<62>-Footnote-25363096
Ref: C API<62>-Footnote-35363161
Ref: C API<62>-Footnote-45363226
Ref: C API<62>-Footnote-55363291
Ref: C API<62>-Footnote-65363355
Ref: C API<62>-Footnote-75363420
Ref: C API<62>-Footnote-85363485
Ref: C API<62>-Footnote-95363550
Ref: C API<62>-Footnote-105363615
Ref: C API<62>-Footnote-115363681
Ref: C API<62>-Footnote-125363747
Ref: C API<62>-Footnote-135363813
Ref: C API<62>-Footnote-145363879
Ref: C API<62>-Footnote-155363945
Node: Python 3 6 6 final5364011
Ref: whatsnew/changelog python-3-6-6-final5364145
Ref: 1c535364145
Node: Python 3 6 6 release candidate 15364273
Ref: whatsnew/changelog python-3-6-6-release-candidate-15364405
Ref: 1c545364405
Node: Core and Builtins<147>5364786
Ref: whatsnew/changelog id7855364898
Ref: 1c555364898
Ref: Core and Builtins<147>-Footnote-15366480
Ref: Core and Builtins<147>-Footnote-25366545
Ref: Core and Builtins<147>-Footnote-35366610
Ref: Core and Builtins<147>-Footnote-45366675
Ref: Core and Builtins<147>-Footnote-55366740
Ref: Core and Builtins<147>-Footnote-65366805
Ref: Core and Builtins<147>-Footnote-75366870
Ref: Core and Builtins<147>-Footnote-85366935
Ref: Core and Builtins<147>-Footnote-95367000
Ref: Core and Builtins<147>-Footnote-105367065
Ref: Core and Builtins<147>-Footnote-115367131
Ref: Core and Builtins<147>-Footnote-125367197
Node: Library<150>5367263
Ref: whatsnew/changelog id7865367401
Ref: 1c565367401
Ref: Library<150>-Footnote-15372882
Ref: Library<150>-Footnote-25372947
Ref: Library<150>-Footnote-35373012
Ref: Library<150>-Footnote-45373077
Ref: Library<150>-Footnote-55373142
Ref: Library<150>-Footnote-65373207
Ref: Library<150>-Footnote-75373272
Ref: Library<150>-Footnote-85373337
Ref: Library<150>-Footnote-95373402
Ref: Library<150>-Footnote-105373467
Ref: Library<150>-Footnote-115373533
Ref: Library<150>-Footnote-125373599
Ref: Library<150>-Footnote-135373665
Ref: Library<150>-Footnote-145373731
Ref: Library<150>-Footnote-155373797
Ref: Library<150>-Footnote-165373863
Ref: Library<150>-Footnote-175373929
Ref: Library<150>-Footnote-185373995
Ref: Library<150>-Footnote-195374061
Ref: Library<150>-Footnote-205374127
Ref: Library<150>-Footnote-215374193
Ref: Library<150>-Footnote-225374260
Ref: Library<150>-Footnote-235374326
Ref: Library<150>-Footnote-245374392
Ref: Library<150>-Footnote-255374458
Ref: Library<150>-Footnote-265374524
Ref: Library<150>-Footnote-275374590
Ref: Library<150>-Footnote-285374656
Ref: Library<150>-Footnote-295374699
Ref: Library<150>-Footnote-305374765
Ref: Library<150>-Footnote-315374831
Ref: Library<150>-Footnote-325374897
Ref: Library<150>-Footnote-335374963
Ref: Library<150>-Footnote-345375029
Ref: Library<150>-Footnote-355375095
Ref: Library<150>-Footnote-365375161
Ref: Library<150>-Footnote-375375227
Ref: Library<150>-Footnote-385375293
Ref: Library<150>-Footnote-395375359
Node: Documentation<65>5375425
Ref: whatsnew/changelog id7875375550
Ref: 1c575375550
Ref: Documentation<65>-Footnote-15377041
Ref: Documentation<65>-Footnote-25377106
Ref: Documentation<65>-Footnote-35377171
Ref: Documentation<65>-Footnote-45377236
Ref: Documentation<65>-Footnote-55377301
Ref: Documentation<65>-Footnote-65377366
Ref: Documentation<65>-Footnote-75377431
Ref: Documentation<65>-Footnote-85377496
Ref: Documentation<65>-Footnote-95377561
Ref: Documentation<65>-Footnote-105377626
Ref: Documentation<65>-Footnote-115377692
Ref: Documentation<65>-Footnote-125377758
Ref: Documentation<65>-Footnote-135377823
Node: Tests<65>5377889
Ref: whatsnew/changelog id7885378011
Ref: 1c585378011
Ref: Tests<65>-Footnote-15378233
Ref: Tests<65>-Footnote-25378298
Node: Build<70>5378363
Ref: whatsnew/changelog id7895378479
Ref: 1c595378479
Ref: Build<70>-Footnote-15379276
Ref: Build<70>-Footnote-25379340
Ref: Build<70>-Footnote-35379405
Ref: Build<70>-Footnote-45379470
Ref: Build<70>-Footnote-55379535
Node: Windows<62>5379600
Ref: whatsnew/changelog id7905379716
Ref: 1c5a5379716
Ref: Windows<62>-Footnote-15379853
Node: macOS<49>5379918
Ref: whatsnew/changelog id7915380033
Ref: 1c5b5380033
Ref: macOS<49>-Footnote-15380174
Node: IDLE<50>5380239
Ref: whatsnew/changelog id7925380358
Ref: 1c5c5380358
Ref: IDLE<50>-Footnote-15382427
Ref: IDLE<50>-Footnote-25382492
Ref: IDLE<50>-Footnote-35382557
Ref: IDLE<50>-Footnote-45382622
Ref: IDLE<50>-Footnote-55382687
Ref: IDLE<50>-Footnote-65382752
Ref: IDLE<50>-Footnote-75382817
Ref: IDLE<50>-Footnote-85382882
Ref: IDLE<50>-Footnote-95382947
Ref: IDLE<50>-Footnote-105383012
Ref: IDLE<50>-Footnote-115383078
Ref: IDLE<50>-Footnote-125383144
Node: Tools/Demos<37>5383210
Ref: whatsnew/changelog id7935383329
Ref: 1c5d5383329
Ref: Tools/Demos<37>-Footnote-15384084
Ref: Tools/Demos<37>-Footnote-25384149
Ref: Tools/Demos<37>-Footnote-35384214
Ref: Tools/Demos<37>-Footnote-45384279
Ref: Tools/Demos<37>-Footnote-55384344
Node: C API<63>5384409
Ref: whatsnew/changelog id7945384511
Ref: 1c5e5384511
Ref: C API<63>-Footnote-15384724
Node: Python 3 6 5 final5384789
Ref: whatsnew/changelog python-3-6-5-final5384935
Ref: 1c5f5384935
Node: Tests<66>5385068
Ref: whatsnew/changelog id7955385150
Ref: 1c605385150
Ref: Tests<66>-Footnote-15385304
Node: Build<71>5385369
Ref: whatsnew/changelog id7965385451
Ref: 1c615385451
Ref: Build<71>-Footnote-15385588
Node: Python 3 6 5 release candidate 15385653
Ref: whatsnew/changelog python-3-6-5-release-candidate-15385785
Ref: 1c625385785
Node: Security<47>5386192
Ref: whatsnew/changelog id7975386304
Ref: 1c635386304
Ref: Security<47>-Footnote-15386735
Ref: Security<47>-Footnote-25386800
Ref: Security<47>-Footnote-35386865
Ref: Security<47>-Footnote-45386920
Node: Core and Builtins<148>5386975
Ref: whatsnew/changelog id7985387108
Ref: 1c645387108
Ref: Core and Builtins<148>-Footnote-15389282
Ref: Core and Builtins<148>-Footnote-25389347
Ref: Core and Builtins<148>-Footnote-35389412
Ref: Core and Builtins<148>-Footnote-45389477
Ref: Core and Builtins<148>-Footnote-55389542
Ref: Core and Builtins<148>-Footnote-65389607
Ref: Core and Builtins<148>-Footnote-75389672
Ref: Core and Builtins<148>-Footnote-85389737
Ref: Core and Builtins<148>-Footnote-95389802
Ref: Core and Builtins<148>-Footnote-105389867
Ref: Core and Builtins<148>-Footnote-115389933
Ref: Core and Builtins<148>-Footnote-125389999
Ref: Core and Builtins<148>-Footnote-135390065
Ref: Core and Builtins<148>-Footnote-145390131
Node: Library<151>5390197
Ref: whatsnew/changelog id7995390335
Ref: 1c655390335
Ref: Library<151>-Footnote-15396260
Ref: Library<151>-Footnote-25396325
Ref: Library<151>-Footnote-35396390
Ref: Library<151>-Footnote-45396455
Ref: Library<151>-Footnote-55396520
Ref: Library<151>-Footnote-65396585
Ref: Library<151>-Footnote-75396650
Ref: Library<151>-Footnote-85396715
Ref: Library<151>-Footnote-95396780
Ref: Library<151>-Footnote-105396845
Ref: Library<151>-Footnote-115396911
Ref: Library<151>-Footnote-125396977
Ref: Library<151>-Footnote-135397043
Ref: Library<151>-Footnote-145397109
Ref: Library<151>-Footnote-155397175
Ref: Library<151>-Footnote-165397241
Ref: Library<151>-Footnote-175397307
Ref: Library<151>-Footnote-185397373
Ref: Library<151>-Footnote-195397439
Ref: Library<151>-Footnote-205397505
Ref: Library<151>-Footnote-215397571
Ref: Library<151>-Footnote-225397637
Ref: Library<151>-Footnote-235397703
Ref: Library<151>-Footnote-245397769
Ref: Library<151>-Footnote-255397835
Ref: Library<151>-Footnote-265397901
Ref: Library<151>-Footnote-275397967
Ref: Library<151>-Footnote-285398033
Ref: Library<151>-Footnote-295398099
Ref: Library<151>-Footnote-305398165
Ref: Library<151>-Footnote-315398231
Ref: Library<151>-Footnote-325398297
Ref: Library<151>-Footnote-335398363
Ref: Library<151>-Footnote-345398429
Ref: Library<151>-Footnote-355398495
Ref: Library<151>-Footnote-365398561
Ref: Library<151>-Footnote-375398627
Ref: Library<151>-Footnote-385398693
Ref: Library<151>-Footnote-395398759
Ref: Library<151>-Footnote-405398825
Node: Documentation<66>5398891
Ref: whatsnew/changelog id8005399016
Ref: 1c665399016
Ref: Documentation<66>-Footnote-15399852
Ref: Documentation<66>-Footnote-25399917
Ref: Documentation<66>-Footnote-35399982
Ref: Documentation<66>-Footnote-45400046
Ref: Documentation<66>-Footnote-55400111
Ref: Documentation<66>-Footnote-65400176
Node: Tests<67>5400241
Ref: whatsnew/changelog id8015400363
Ref: 1c675400363
Ref: Tests<67>-Footnote-15401024
Ref: Tests<67>-Footnote-25401089
Ref: Tests<67>-Footnote-35401154
Ref: Tests<67>-Footnote-45401219
Node: Build<72>5401284
Ref: whatsnew/changelog id8025401400
Ref: 1c685401400
Ref: Build<72>-Footnote-15401589
Node: Windows<63>5401654
Ref: whatsnew/changelog id8035401770
Ref: 1c695401770
Ref: Windows<63>-Footnote-15402720
Ref: Windows<63>-Footnote-25402785
Ref: Windows<63>-Footnote-35402850
Ref: Windows<63>-Footnote-45402915
Ref: Windows<63>-Footnote-55402980
Ref: Windows<63>-Footnote-65403045
Ref: Windows<63>-Footnote-75403110
Ref: Windows<63>-Footnote-85403175
Node: macOS<50>5403240
Ref: whatsnew/changelog id8045403355
Ref: 1c6a5403355
Ref: macOS<50>-Footnote-15403748
Node: IDLE<51>5403813
Ref: whatsnew/changelog id8055403932
Ref: 1c6b5403932
Ref: IDLE<51>-Footnote-15405427
Ref: IDLE<51>-Footnote-25405492
Ref: IDLE<51>-Footnote-35405557
Ref: IDLE<51>-Footnote-45405622
Ref: IDLE<51>-Footnote-55405687
Ref: IDLE<51>-Footnote-65405752
Ref: IDLE<51>-Footnote-75405817
Ref: IDLE<51>-Footnote-85405882
Node: Tools/Demos<38>5405947
Ref: whatsnew/changelog id8065406066
Ref: 1c6c5406066
Ref: Tools/Demos<38>-Footnote-15406486
Ref: Tools/Demos<38>-Footnote-25406551
Node: C API<64>5406616
Ref: whatsnew/changelog id8075406718
Ref: 1c6d5406718
Ref: C API<64>-Footnote-15406968
Node: Python 3 6 4 final5407033
Ref: whatsnew/changelog python-3-6-4-final5407179
Ref: 1c6e5407179
Node: Python 3 6 4 release candidate 15407328
Ref: whatsnew/changelog python-3-6-4-release-candidate-15407460
Ref: 1c6f5407460
Node: Core and Builtins<149>5407841
Ref: whatsnew/changelog id8085407953
Ref: 1c705407953
Ref: Core and Builtins<149>-Footnote-15412685
Ref: Core and Builtins<149>-Footnote-25412750
Ref: Core and Builtins<149>-Footnote-35412815
Ref: Core and Builtins<149>-Footnote-45412880
Ref: Core and Builtins<149>-Footnote-55412945
Ref: Core and Builtins<149>-Footnote-65413010
Ref: Core and Builtins<149>-Footnote-75413075
Ref: Core and Builtins<149>-Footnote-85413140
Ref: Core and Builtins<149>-Footnote-95413205
Ref: Core and Builtins<149>-Footnote-105413270
Ref: Core and Builtins<149>-Footnote-115413336
Ref: Core and Builtins<149>-Footnote-125413402
Ref: Core and Builtins<149>-Footnote-135413468
Ref: Core and Builtins<149>-Footnote-145413534
Ref: Core and Builtins<149>-Footnote-155413600
Ref: Core and Builtins<149>-Footnote-165413666
Ref: Core and Builtins<149>-Footnote-175413732
Ref: Core and Builtins<149>-Footnote-185413798
Ref: Core and Builtins<149>-Footnote-195413864
Ref: Core and Builtins<149>-Footnote-205413930
Ref: Core and Builtins<149>-Footnote-215413996
Ref: Core and Builtins<149>-Footnote-225414062
Ref: Core and Builtins<149>-Footnote-235414128
Ref: Core and Builtins<149>-Footnote-245414194
Node: Library<152>5414260
Ref: whatsnew/changelog id8095414398
Ref: 1c715414398
Ref: Library<152>-Footnote-15421723
Ref: Library<152>-Footnote-25421788
Ref: Library<152>-Footnote-35421853
Ref: Library<152>-Footnote-45421918
Ref: Library<152>-Footnote-55421983
Ref: Library<152>-Footnote-65422048
Ref: Library<152>-Footnote-75422113
Ref: Library<152>-Footnote-85422178
Ref: Library<152>-Footnote-95422243
Ref: Library<152>-Footnote-105422308
Ref: Library<152>-Footnote-115422374
Ref: Library<152>-Footnote-125422440
Ref: Library<152>-Footnote-135422506
Ref: Library<152>-Footnote-145422572
Ref: Library<152>-Footnote-155422638
Ref: Library<152>-Footnote-165422704
Ref: Library<152>-Footnote-175422769
Ref: Library<152>-Footnote-185422835
Ref: Library<152>-Footnote-195422901
Ref: Library<152>-Footnote-205422967
Ref: Library<152>-Footnote-215423033
Ref: Library<152>-Footnote-225423099
Ref: Library<152>-Footnote-235423165
Ref: Library<152>-Footnote-245423231
Ref: Library<152>-Footnote-255423297
Ref: Library<152>-Footnote-265423363
Ref: Library<152>-Footnote-275423429
Ref: Library<152>-Footnote-285423495
Ref: Library<152>-Footnote-295423561
Ref: Library<152>-Footnote-305423627
Ref: Library<152>-Footnote-315423693
Ref: Library<152>-Footnote-325423759
Ref: Library<152>-Footnote-335423825
Ref: Library<152>-Footnote-345423891
Ref: Library<152>-Footnote-355423957
Ref: Library<152>-Footnote-365424023
Ref: Library<152>-Footnote-375424089
Ref: Library<152>-Footnote-385424155
Ref: Library<152>-Footnote-395424221
Ref: Library<152>-Footnote-405424287
Ref: Library<152>-Footnote-415424353
Ref: Library<152>-Footnote-425424419
Ref: Library<152>-Footnote-435424485
Ref: Library<152>-Footnote-445424551
Ref: Library<152>-Footnote-455424617
Ref: Library<152>-Footnote-465424683
Ref: Library<152>-Footnote-475424749
Ref: Library<152>-Footnote-485424815
Ref: Library<152>-Footnote-495424881
Ref: Library<152>-Footnote-505424947
Ref: Library<152>-Footnote-515425013
Ref: Library<152>-Footnote-525425079
Node: Documentation<67>5425145
Ref: whatsnew/changelog id8105425270
Ref: 1c725425270
Ref: Documentation<67>-Footnote-15425759
Ref: Documentation<67>-Footnote-25425824
Ref: Documentation<67>-Footnote-35425889
Node: Tests<68>5425954
Ref: whatsnew/changelog id8115426076
Ref: 1c735426076
Ref: Tests<68>-Footnote-15426754
Ref: Tests<68>-Footnote-25426819
Ref: Tests<68>-Footnote-35426884
Ref: Tests<68>-Footnote-45426949
Node: Build<73>5427014
Ref: whatsnew/changelog id8125427130
Ref: 1c745427130
Ref: Build<73>-Footnote-15428034
Ref: Build<73>-Footnote-25428099
Ref: Build<73>-Footnote-35428164
Ref: Build<73>-Footnote-45428229
Ref: Build<73>-Footnote-55428294
Ref: Build<73>-Footnote-65428359
Ref: Build<73>-Footnote-75428424
Ref: Build<73>-Footnote-85428489
Ref: Build<73>-Footnote-95428554
Node: Windows<64>5428619
Ref: whatsnew/changelog id8135428735
Ref: 1c755428735
Ref: Windows<64>-Footnote-15429053
Ref: Windows<64>-Footnote-25429117
Node: macOS<51>5429182
Ref: whatsnew/changelog id8145429297
Ref: 1c765429297
Ref: macOS<51>-Footnote-15429431
Node: IDLE<52>5429496
Ref: whatsnew/changelog id8155429615
Ref: 1c775429615
Ref: IDLE<52>-Footnote-15432952
Ref: IDLE<52>-Footnote-25433017
Ref: IDLE<52>-Footnote-35433082
Ref: IDLE<52>-Footnote-45433147
Ref: IDLE<52>-Footnote-55433212
Ref: IDLE<52>-Footnote-65433277
Ref: IDLE<52>-Footnote-75433342
Ref: IDLE<52>-Footnote-85433407
Ref: IDLE<52>-Footnote-95433472
Ref: IDLE<52>-Footnote-105433537
Ref: IDLE<52>-Footnote-115433603
Ref: IDLE<52>-Footnote-125433669
Ref: IDLE<52>-Footnote-135433735
Ref: IDLE<52>-Footnote-145433801
Node: Tools/Demos<39>5433869
Ref: whatsnew/changelog id8165433988
Ref: 1c785433988
Ref: Tools/Demos<39>-Footnote-15434278
Node: C API<65>5434343
Ref: whatsnew/changelog id8175434445
Ref: 1c795434445
Ref: C API<65>-Footnote-15435173
Ref: C API<65>-Footnote-25435238
Ref: C API<65>-Footnote-35435303
Ref: C API<65>-Footnote-45435368
Node: Python 3 6 3 final5435433
Ref: whatsnew/changelog python-3-6-3-final5435579
Ref: 1c7a5435579
Node: Library<153>5435717
Ref: whatsnew/changelog id8185435802
Ref: 1c7b5435802
Ref: Library<153>-Footnote-15436004
Node: Build<74>5436069
Ref: whatsnew/changelog id8195436154
Ref: 1c7c5436154
Ref: Build<74>-Footnote-15436445
Ref: Build<74>-Footnote-25436510
Node: Python 3 6 3 release candidate 15436575
Ref: whatsnew/changelog python-3-6-3-release-candidate-15436707
Ref: 1c7d5436707
Node: Security<48>5437074
Ref: whatsnew/changelog id8205437186
Ref: 1c7e5437186
Ref: Security<48>-Footnote-15437492
Ref: Security<48>-Footnote-25437557
Node: Core and Builtins<150>5437622
Ref: whatsnew/changelog id8215437755
Ref: 1c7f5437755
Ref: Core and Builtins<150>-Footnote-15441286
Ref: Core and Builtins<150>-Footnote-25441351
Ref: Core and Builtins<150>-Footnote-35441416
Ref: Core and Builtins<150>-Footnote-45441481
Ref: Core and Builtins<150>-Footnote-55441546
Ref: Core and Builtins<150>-Footnote-65441611
Ref: Core and Builtins<150>-Footnote-75441676
Ref: Core and Builtins<150>-Footnote-85441741
Ref: Core and Builtins<150>-Footnote-95441806
Ref: Core and Builtins<150>-Footnote-105441871
Ref: Core and Builtins<150>-Footnote-115441937
Ref: Core and Builtins<150>-Footnote-125442003
Ref: Core and Builtins<150>-Footnote-135442069
Ref: Core and Builtins<150>-Footnote-145442135
Ref: Core and Builtins<150>-Footnote-155442201
Ref: Core and Builtins<150>-Footnote-165442267
Ref: Core and Builtins<150>-Footnote-175442333
Ref: Core and Builtins<150>-Footnote-185442399
Ref: Core and Builtins<150>-Footnote-195442465
Ref: Core and Builtins<150>-Footnote-205442531
Ref: Core and Builtins<150>-Footnote-215442597
Ref: Core and Builtins<150>-Footnote-225442663
Node: Library<154>5442729
Ref: whatsnew/changelog id8225442867
Ref: 1c805442867
Ref: Library<154>-Footnote-15448868
Ref: Library<154>-Footnote-25448933
Ref: Library<154>-Footnote-35448998
Ref: Library<154>-Footnote-45449063
Ref: Library<154>-Footnote-55449128
Ref: Library<154>-Footnote-65449193
Ref: Library<154>-Footnote-75449258
Ref: Library<154>-Footnote-85449323
Ref: Library<154>-Footnote-95449388
Ref: Library<154>-Footnote-105449453
Ref: Library<154>-Footnote-115449519
Ref: Library<154>-Footnote-125449585
Ref: Library<154>-Footnote-135449651
Ref: Library<154>-Footnote-145449717
Ref: Library<154>-Footnote-155449783
Ref: Library<154>-Footnote-165449848
Ref: Library<154>-Footnote-175449914
Ref: Library<154>-Footnote-185449980
Ref: Library<154>-Footnote-195450023
Ref: Library<154>-Footnote-205450089
Ref: Library<154>-Footnote-215450155
Ref: Library<154>-Footnote-225450221
Ref: Library<154>-Footnote-235450287
Ref: Library<154>-Footnote-245450353
Ref: Library<154>-Footnote-255450419
Ref: Library<154>-Footnote-265450485
Ref: Library<154>-Footnote-275450551
Ref: Library<154>-Footnote-285450617
Ref: Library<154>-Footnote-295450683
Ref: Library<154>-Footnote-305450749
Ref: Library<154>-Footnote-315450815
Ref: Library<154>-Footnote-325450881
Ref: Library<154>-Footnote-335450947
Ref: Library<154>-Footnote-345451013
Ref: Library<154>-Footnote-355451079
Ref: Library<154>-Footnote-365451145
Ref: Library<154>-Footnote-375451211
Ref: Library<154>-Footnote-385451277
Ref: Library<154>-Footnote-395451343
Ref: Library<154>-Footnote-405451409
Ref: Library<154>-Footnote-415451475
Ref: Library<154>-Footnote-425451541
Node: Documentation<68>5451607
Ref: whatsnew/changelog id8235451732
Ref: 1c815451732
Ref: Documentation<68>-Footnote-15452155
Ref: Documentation<68>-Footnote-25452220
Ref: Documentation<68>-Footnote-35452285
Node: Tests<69>5452350
Ref: whatsnew/changelog id8245452472
Ref: 1c825452472
Ref: Tests<69>-Footnote-15453177
Ref: Tests<69>-Footnote-25453242
Ref: Tests<69>-Footnote-35453307
Ref: Tests<69>-Footnote-45453372
Node: Build<75>5453437
Ref: whatsnew/changelog id8255453553
Ref: 1c835453553
Ref: Build<75>-Footnote-15453728
Node: Windows<65>5453793
Ref: whatsnew/changelog id8265453908
Ref: 1c845453908
Ref: Windows<65>-Footnote-15454416
Ref: Windows<65>-Footnote-25454481
Ref: Windows<65>-Footnote-35454546
Ref: Windows<65>-Footnote-45454611
Node: IDLE<53>5454676
Ref: whatsnew/changelog id8275454797
Ref: 1c855454797
Ref: IDLE<53>-Footnote-15463630
Ref: IDLE<53>-Footnote-25463695
Ref: IDLE<53>-Footnote-35463760
Ref: IDLE<53>-Footnote-45463825
Ref: IDLE<53>-Footnote-55463890
Ref: IDLE<53>-Footnote-65463955
Ref: IDLE<53>-Footnote-75464020
Ref: IDLE<53>-Footnote-85464085
Ref: IDLE<53>-Footnote-95464150
Ref: IDLE<53>-Footnote-105464215
Ref: IDLE<53>-Footnote-115464281
Ref: IDLE<53>-Footnote-125464347
Ref: IDLE<53>-Footnote-135464413
Ref: IDLE<53>-Footnote-145464479
Ref: IDLE<53>-Footnote-155464545
Ref: IDLE<53>-Footnote-165464611
Ref: IDLE<53>-Footnote-175464677
Ref: IDLE<53>-Footnote-185464743
Ref: IDLE<53>-Footnote-195464809
Ref: IDLE<53>-Footnote-205464875
Ref: IDLE<53>-Footnote-215464941
Ref: IDLE<53>-Footnote-225465007
Ref: IDLE<53>-Footnote-235465073
Ref: IDLE<53>-Footnote-245465139
Ref: IDLE<53>-Footnote-255465205
Ref: IDLE<53>-Footnote-265465271
Ref: IDLE<53>-Footnote-275465337
Ref: IDLE<53>-Footnote-285465403
Ref: IDLE<53>-Footnote-295465469
Ref: IDLE<53>-Footnote-305465535
Ref: IDLE<53>-Footnote-315465601
Ref: IDLE<53>-Footnote-325465667
Ref: IDLE<53>-Footnote-335465733
Ref: IDLE<53>-Footnote-345465799
Ref: IDLE<53>-Footnote-355465864
Ref: IDLE<53>-Footnote-365465930
Ref: IDLE<53>-Footnote-375465996
Ref: IDLE<53>-Footnote-385466062
Ref: IDLE<53>-Footnote-395466128
Ref: IDLE<53>-Footnote-405466194
Ref: IDLE<53>-Footnote-415466260
Ref: IDLE<53>-Footnote-425466326
Ref: IDLE<53>-Footnote-435466392
Node: Tools/Demos<40>5466457
Ref: whatsnew/changelog id8285466558
Ref: 1c865466558
Ref: Tools/Demos<40>-Footnote-15467120
Ref: Tools/Demos<40>-Footnote-25467185
Node: Python 3 6 2 final5467227
Ref: whatsnew/changelog python-3-6-2-final5467373
Ref: 1c875467373
Node: Python 3 6 2 release candidate 25467494
Ref: whatsnew/changelog python-3-6-2-release-candidate-25467640
Ref: 1c885467640
Node: Security<49>5467787
Ref: whatsnew/changelog id8295467868
Ref: 1c895467868
Ref: Security<49>-Footnote-15468993
Ref: Security<49>-Footnote-25469058
Ref: Security<49>-Footnote-35469123
Ref: Security<49>-Footnote-45469178
Ref: Security<49>-Footnote-55469233
Ref: Security<49>-Footnote-65469288
Ref: Security<49>-Footnote-75469343
Ref: Security<49>-Footnote-85469398
Ref: Security<49>-Footnote-95469453
Node: Python 3 6 2 release candidate 15469518
Ref: whatsnew/changelog python-3-6-2-release-candidate-15469664
Ref: 1c8a5469664
Node: Security<50>5470051
Ref: whatsnew/changelog id8305470163
Ref: 1c8b5470163
Ref: Security<50>-Footnote-15470436
Ref: Security<50>-Footnote-25470501
Ref: Security<50>-Footnote-35470556
Node: Core and Builtins<151>5470611
Ref: whatsnew/changelog id8315470744
Ref: 1c8c5470744
Ref: Core and Builtins<151>-Footnote-15472744
Ref: Core and Builtins<151>-Footnote-25472809
Ref: Core and Builtins<151>-Footnote-35472874
Ref: Core and Builtins<151>-Footnote-45472939
Ref: Core and Builtins<151>-Footnote-55473004
Ref: Core and Builtins<151>-Footnote-65473069
Ref: Core and Builtins<151>-Footnote-75473134
Ref: Core and Builtins<151>-Footnote-85473199
Ref: Core and Builtins<151>-Footnote-95473264
Ref: Core and Builtins<151>-Footnote-105473329
Ref: Core and Builtins<151>-Footnote-115473395
Ref: Core and Builtins<151>-Footnote-125473461
Ref: Core and Builtins<151>-Footnote-135473527
Ref: Core and Builtins<151>-Footnote-145473593
Ref: Core and Builtins<151>-Footnote-155473659
Node: Library<155>5473725
Ref: whatsnew/changelog id8325473854
Ref: 1c8d5473854
Ref: Library<155>-Footnote-15482282
Ref: Library<155>-Footnote-25482347
Ref: Library<155>-Footnote-35482412
Ref: Library<155>-Footnote-45482477
Ref: Library<155>-Footnote-55482542
Ref: Library<155>-Footnote-65482607
Ref: Library<155>-Footnote-75482672
Ref: Library<155>-Footnote-85482737
Ref: Library<155>-Footnote-95482802
Ref: Library<155>-Footnote-105482867
Ref: Library<155>-Footnote-115482933
Ref: Library<155>-Footnote-125482999
Ref: Library<155>-Footnote-135483065
Ref: Library<155>-Footnote-145483131
Ref: Library<155>-Footnote-155483197
Ref: Library<155>-Footnote-165483263
Ref: Library<155>-Footnote-175483329
Ref: Library<155>-Footnote-185483395
Ref: Library<155>-Footnote-195483461
Ref: Library<155>-Footnote-205483527
Ref: Library<155>-Footnote-215483593
Ref: Library<155>-Footnote-225483659
Ref: Library<155>-Footnote-235483725
Ref: Library<155>-Footnote-245483791
Ref: Library<155>-Footnote-255483857
Ref: Library<155>-Footnote-265483923
Ref: Library<155>-Footnote-275483989
Ref: Library<155>-Footnote-285484055
Ref: Library<155>-Footnote-295484121
Ref: Library<155>-Footnote-305484187
Ref: Library<155>-Footnote-315484253
Ref: Library<155>-Footnote-325484319
Ref: Library<155>-Footnote-335484385
Ref: Library<155>-Footnote-345484451
Ref: Library<155>-Footnote-355484517
Ref: Library<155>-Footnote-365484583
Ref: Library<155>-Footnote-375484649
Ref: Library<155>-Footnote-385484715
Ref: Library<155>-Footnote-395484781
Ref: Library<155>-Footnote-405484847
Ref: Library<155>-Footnote-415484913
Ref: Library<155>-Footnote-425484979
Ref: Library<155>-Footnote-435485045
Ref: Library<155>-Footnote-445485111
Ref: Library<155>-Footnote-455485177
Ref: Library<155>-Footnote-465485243
Ref: Library<155>-Footnote-475485309
Ref: Library<155>-Footnote-485485375
Ref: Library<155>-Footnote-495485441
Ref: Library<155>-Footnote-505485507
Ref: Library<155>-Footnote-515485573
Ref: Library<155>-Footnote-525485639
Ref: Library<155>-Footnote-535485705
Ref: Library<155>-Footnote-545485771
Ref: Library<155>-Footnote-555485837
Ref: Library<155>-Footnote-565485902
Ref: Library<155>-Footnote-575485968
Ref: Library<155>-Footnote-585486034
Ref: Library<155>-Footnote-595486100
Ref: Library<155>-Footnote-605486166
Node: IDLE<54>5486232
Ref: whatsnew/changelog id8335486348
Ref: 1c8e5486348
Ref: IDLE<54>-Footnote-15487353
Ref: IDLE<54>-Footnote-25487418
Ref: IDLE<54>-Footnote-35487483
Ref: IDLE<54>-Footnote-45487548
Ref: IDLE<54>-Footnote-55487613
Ref: IDLE<54>-Footnote-65487678
Node: C API<66>5487743
Ref: whatsnew/changelog id8345487856
Ref: 1c8f5487856
Ref: C API<66>-Footnote-15488044
Node: Build<76>5488109
Ref: whatsnew/changelog id8355488231
Ref: 1c905488231
Ref: Build<76>-Footnote-15489040
Ref: Build<76>-Footnote-25489105
Ref: Build<76>-Footnote-35489170
Ref: Build<76>-Footnote-45489235
Ref: Build<76>-Footnote-55489300
Node: Documentation<69>5489365
Ref: whatsnew/changelog id8365489493
Ref: 1c915489493
Ref: Documentation<69>-Footnote-15490222
Ref: Documentation<69>-Footnote-25490287
Ref: Documentation<69>-Footnote-35490352
Node: Tools/Demos<41>5490417
Ref: whatsnew/changelog id8375490545
Ref: 1c925490545
Ref: Tools/Demos<41>-Footnote-15490735
Node: Tests<70>5490800
Ref: whatsnew/changelog id8385490922
Ref: 1c935490922
Ref: Tests<70>-Footnote-15491583
Ref: Tests<70>-Footnote-25491648
Node: Windows<66>5491713
Ref: whatsnew/changelog id8395491811
Ref: 1c945491811
Ref: Windows<66>-Footnote-15492255
Ref: Windows<66>-Footnote-25492320
Node: Python 3 6 1 final5492385
Ref: whatsnew/changelog python-3-6-1-final5492531
Ref: 1c955492531
Node: Core and Builtins<152>5492689
Ref: whatsnew/changelog id8405492784
Ref: 1c965492784
Ref: Core and Builtins<152>-Footnote-15493403
Ref: Core and Builtins<152>-Footnote-25493468
Node: Build<77>5493533
Ref: whatsnew/changelog id8415493628
Ref: 1c975493628
Ref: Build<77>-Footnote-15493810
Node: Python 3 6 1 release candidate 15493875
Ref: whatsnew/changelog python-3-6-1-release-candidate-15494007
Ref: 1c985494007
Node: Core and Builtins<153>5494336
Ref: whatsnew/changelog id8425494448
Ref: 1c995494448
Ref: Core and Builtins<153>-Footnote-15497280
Ref: Core and Builtins<153>-Footnote-25497345
Ref: Core and Builtins<153>-Footnote-35497410
Ref: Core and Builtins<153>-Footnote-45497475
Ref: Core and Builtins<153>-Footnote-55497540
Ref: Core and Builtins<153>-Footnote-65497605
Ref: Core and Builtins<153>-Footnote-75497670
Ref: Core and Builtins<153>-Footnote-85497735
Ref: Core and Builtins<153>-Footnote-95497800
Ref: Core and Builtins<153>-Footnote-105497865
Ref: Core and Builtins<153>-Footnote-115497931
Ref: Core and Builtins<153>-Footnote-125497997
Ref: Core and Builtins<153>-Footnote-135498063
Ref: Core and Builtins<153>-Footnote-145498129
Ref: Core and Builtins<153>-Footnote-155498195
Ref: Core and Builtins<153>-Footnote-165498261
Ref: Core and Builtins<153>-Footnote-175498327
Ref: Core and Builtins<153>-Footnote-185498393
Ref: Core and Builtins<153>-Footnote-195498459
Ref: Core and Builtins<153>-Footnote-205498525
Ref: Core and Builtins<153>-Footnote-215498591
Ref: Core and Builtins<153>-Footnote-225498657
Node: Library<156>5498723
Ref: whatsnew/changelog id8435498852
Ref: 1c9a5498852
Ref: Library<156>-Footnote-15504499
Ref: Library<156>-Footnote-25504564
Ref: Library<156>-Footnote-35504629
Ref: Library<156>-Footnote-45504694
Ref: Library<156>-Footnote-55504759
Ref: Library<156>-Footnote-65504824
Ref: Library<156>-Footnote-75504889
Ref: Library<156>-Footnote-85504954
Ref: Library<156>-Footnote-95505019
Ref: Library<156>-Footnote-105505084
Ref: Library<156>-Footnote-115505150
Ref: Library<156>-Footnote-125505216
Ref: Library<156>-Footnote-135505282
Ref: Library<156>-Footnote-145505348
Ref: Library<156>-Footnote-155505414
Ref: Library<156>-Footnote-165505480
Ref: Library<156>-Footnote-175505546
Ref: Library<156>-Footnote-185505612
Ref: Library<156>-Footnote-195505678
Ref: Library<156>-Footnote-205505744
Ref: Library<156>-Footnote-215505810
Ref: Library<156>-Footnote-225505876
Ref: Library<156>-Footnote-235505942
Ref: Library<156>-Footnote-245506008
Ref: Library<156>-Footnote-255506074
Ref: Library<156>-Footnote-265506140
Ref: Library<156>-Footnote-275506206
Ref: Library<156>-Footnote-285506249
Ref: Library<156>-Footnote-295506315
Ref: Library<156>-Footnote-305506381
Ref: Library<156>-Footnote-315506447
Ref: Library<156>-Footnote-325506513
Ref: Library<156>-Footnote-335506579
Ref: Library<156>-Footnote-345506645
Ref: Library<156>-Footnote-355506711
Ref: Library<156>-Footnote-365506776
Ref: Library<156>-Footnote-375506842
Ref: Library<156>-Footnote-385506908
Ref: Library<156>-Footnote-395506974
Ref: Library<156>-Footnote-405507040
Ref: Library<156>-Footnote-415507106
Ref: Library<156>-Footnote-425507172
Ref: Library<156>-Footnote-435507238
Ref: Library<156>-Footnote-445507304
Node: IDLE<55>5507370
Ref: whatsnew/changelog id8445507488
Ref: 1c9b5507488
Ref: IDLE<55>-Footnote-15507777
Ref: IDLE<55>-Footnote-25507842
Node: Windows<67>5507907
Ref: whatsnew/changelog id8455508022
Ref: 1c9c5508022
Ref: Windows<67>-Footnote-15508669
Ref: Windows<67>-Footnote-25508734
Ref: Windows<67>-Footnote-35508799
Ref: Windows<67>-Footnote-45508864
Ref: Windows<67>-Footnote-55508929
Ref: Windows<67>-Footnote-65508971
Ref: Windows<67>-Footnote-75509036
Ref: Windows<67>-Footnote-85509101
Node: C API<67>5509166
Ref: whatsnew/changelog id8465509290
Ref: 1c9d5509290
Ref: C API<67>-Footnote-15510116
Ref: C API<67>-Footnote-25510181
Ref: C API<67>-Footnote-35510246
Node: Documentation<70>5510311
Ref: whatsnew/changelog id8475510433
Ref: 1c9e5510433
Ref: Documentation<70>-Footnote-15510970
Ref: Documentation<70>-Footnote-25511035
Ref: Documentation<70>-Footnote-35511100
Ref: Documentation<70>-Footnote-45511165
Node: Tests<71>5511230
Ref: whatsnew/changelog id8485511352
Ref: 1c9f5511352
Ref: Tests<71>-Footnote-15512337
Ref: Tests<71>-Footnote-25512402
Ref: Tests<71>-Footnote-35512467
Ref: Tests<71>-Footnote-45512532
Ref: Tests<71>-Footnote-55512597
Node: Build<78>5512662
Ref: whatsnew/changelog id8495512758
Ref: 1ca05512758
Ref: Build<78>-Footnote-15514019
Ref: Build<78>-Footnote-25514084
Ref: Build<78>-Footnote-35514149
Ref: Build<78>-Footnote-45514214
Ref: Build<78>-Footnote-55514279
Ref: Build<78>-Footnote-65514344
Ref: Build<78>-Footnote-75514409
Ref: Build<78>-Footnote-85514474
Ref: Build<78>-Footnote-95514539
Ref: Build<78>-Footnote-105514604
Node: Python 3 6 0 final5514670
Ref: whatsnew/changelog python-3-6-0-final5514816
Ref: 1ca15514816
Node: Python 3 6 0 release candidate 25514937
Ref: whatsnew/changelog python-3-6-0-release-candidate-25515083
Ref: 1ca25515083
Node: Core and Builtins<154>5515325
Ref: whatsnew/changelog id8505515440
Ref: 1ca35515440
Ref: Core and Builtins<154>-Footnote-15515825
Ref: Core and Builtins<154>-Footnote-25515890
Node: Tools/Demos<42>5515955
Ref: whatsnew/changelog id8515516090
Ref: 1ca45516090
Ref: Tools/Demos<42>-Footnote-15516224
Node: Windows<68>5516289
Ref: whatsnew/changelog id8525516411
Ref: 1ca55516411
Ref: Windows<68>-Footnote-15516537
Node: Build<79>5516602
Ref: whatsnew/changelog id8535516700
Ref: 1ca65516700
Ref: Build<79>-Footnote-15516855
Node: Python 3 6 0 release candidate 15516920
Ref: whatsnew/changelog python-3-6-0-release-candidate-15517067
Ref: 1ca75517067
Node: Core and Builtins<155>5517346
Ref: whatsnew/changelog id8545517458
Ref: 1ca85517458
Ref: Core and Builtins<155>-Footnote-15518267
Ref: Core and Builtins<155>-Footnote-25518332
Ref: Core and Builtins<155>-Footnote-35518397
Ref: Core and Builtins<155>-Footnote-45518462
Node: Library<157>5518527
Ref: whatsnew/changelog id8555518657
Ref: 1ca95518657
Ref: Library<157>-Footnote-15519696
Ref: Library<157>-Footnote-25519761
Ref: Library<157>-Footnote-35519826
Ref: Library<157>-Footnote-45519891
Ref: Library<157>-Footnote-55519956
Ref: Library<157>-Footnote-65520021
Node: C API<68>5520086
Ref: whatsnew/changelog id8565520211
Ref: 1caa5520211
Ref: C API<68>-Footnote-15520369
Node: Documentation<71>5520434
Ref: whatsnew/changelog id8575520562
Ref: 1cab5520562
Ref: Documentation<71>-Footnote-15520902
Ref: Documentation<71>-Footnote-25520967
Node: Tools/Demos<43>5521009
Ref: whatsnew/changelog id8585521119
Ref: 1cac5521119
Ref: Tools/Demos<43>-Footnote-15521285
Node: Python 3 6 0 beta 45521350
Ref: whatsnew/changelog python-3-6-0-beta-45521484
Ref: 1cad5521484
Node: Core and Builtins<156>5521725
Ref: whatsnew/changelog id8595521824
Ref: 1cae5521824
Ref: Core and Builtins<156>-Footnote-15523376
Ref: Core and Builtins<156>-Footnote-25523441
Ref: Core and Builtins<156>-Footnote-35523506
Ref: Core and Builtins<156>-Footnote-45523571
Ref: Core and Builtins<156>-Footnote-55523636
Ref: Core and Builtins<156>-Footnote-65523701
Ref: Core and Builtins<156>-Footnote-75523766
Ref: Core and Builtins<156>-Footnote-85523831
Ref: Core and Builtins<156>-Footnote-95523896
Ref: Core and Builtins<156>-Footnote-105523961
Ref: Core and Builtins<156>-Footnote-115524027
Node: Library<158>5524093
Ref: whatsnew/changelog id8605524218
Ref: 1caf5524218
Ref: Library<158>-Footnote-15526220
Ref: Library<158>-Footnote-25526285
Ref: Library<158>-Footnote-35526350
Ref: Library<158>-Footnote-45526415
Ref: Library<158>-Footnote-55526480
Ref: Library<158>-Footnote-65526545
Ref: Library<158>-Footnote-75526610
Ref: Library<158>-Footnote-85526675
Ref: Library<158>-Footnote-95526740
Ref: Library<158>-Footnote-105526805
Ref: Library<158>-Footnote-115526871
Ref: Library<158>-Footnote-125526937
Ref: Library<158>-Footnote-135527003
Ref: Library<158>-Footnote-145527069
Ref: Library<158>-Footnote-155527135
Ref: Library<158>-Footnote-165527201
Ref: Library<158>-Footnote-175527267
Ref: Library<158>-Footnote-185527333
Node: Documentation<72>5527399
Ref: whatsnew/changelog id8615527511
Ref: 1cb05527511
Ref: Documentation<72>-Footnote-15527662
Node: Tests<72>5527727
Ref: whatsnew/changelog id8625527836
Ref: 1cb15527836
Ref: Tests<72>-Footnote-15528098
Ref: Tests<72>-Footnote-25528163
Node: Build<80>5528228
Ref: whatsnew/changelog id8635528311
Ref: 1cb25528311
Ref: Build<80>-Footnote-15528674
Ref: Build<80>-Footnote-25528739
Ref: Build<80>-Footnote-35528804
Node: Python 3 6 0 beta 35528869
Ref: whatsnew/changelog python-3-6-0-beta-35528990
Ref: 1cb35528990
Node: Core and Builtins<157>5529219
Ref: whatsnew/changelog id8645529318
Ref: 1cb45529318
Ref: Core and Builtins<157>-Footnote-15530225
Ref: Core and Builtins<157>-Footnote-25530290
Ref: Core and Builtins<157>-Footnote-35530355
Ref: Core and Builtins<157>-Footnote-45530420
Ref: Core and Builtins<157>-Footnote-55530485
Ref: Core and Builtins<157>-Footnote-65530550
Ref: Core and Builtins<157>-Footnote-75530615
Node: Library<159>5530680
Ref: whatsnew/changelog id8655530799
Ref: 1cb55530799
Ref: Library<159>-Footnote-15533846
Ref: Library<159>-Footnote-25533911
Ref: Library<159>-Footnote-35533976
Ref: Library<159>-Footnote-45534041
Ref: Library<159>-Footnote-55534106
Ref: Library<159>-Footnote-65534171
Ref: Library<159>-Footnote-75534236
Ref: Library<159>-Footnote-85534301
Ref: Library<159>-Footnote-95534366
Ref: Library<159>-Footnote-105534431
Ref: Library<159>-Footnote-115534497
Ref: Library<159>-Footnote-125534563
Ref: Library<159>-Footnote-135534629
Ref: Library<159>-Footnote-145534695
Ref: Library<159>-Footnote-155534761
Ref: Library<159>-Footnote-165534827
Ref: Library<159>-Footnote-175534893
Ref: Library<159>-Footnote-185534959
Ref: Library<159>-Footnote-195535025
Ref: Library<159>-Footnote-205535091
Ref: Library<159>-Footnote-215535157
Ref: Library<159>-Footnote-225535223
Ref: Library<159>-Footnote-235535289
Ref: Library<159>-Footnote-245535355
Node: Windows<69>5535421
Ref: whatsnew/changelog id8665535527
Ref: 1cb65535527
Ref: Windows<69>-Footnote-15535671
Node: Build<81>5535736
Ref: whatsnew/changelog id8675535839
Ref: 1cb75535839
Ref: Build<81>-Footnote-15536158
Ref: Build<81>-Footnote-25536223
Ref: Build<81>-Footnote-35536288
Node: Tests<73>5536353
Ref: whatsnew/changelog id8685536436
Ref: 1cb85536436
Ref: Tests<73>-Footnote-15536695
Ref: Tests<73>-Footnote-25536760
Node: Python 3 6 0 beta 25536825
Ref: whatsnew/changelog python-3-6-0-beta-25536946
Ref: 1cb95536946
Node: Core and Builtins<158>5537195
Ref: whatsnew/changelog id8695537294
Ref: 1cba5537294
Ref: Core and Builtins<158>-Footnote-15540038
Ref: Core and Builtins<158>-Footnote-25540103
Ref: Core and Builtins<158>-Footnote-35540168
Ref: Core and Builtins<158>-Footnote-45540233
Ref: Core and Builtins<158>-Footnote-55540298
Ref: Core and Builtins<158>-Footnote-65540363
Ref: Core and Builtins<158>-Footnote-75540428
Ref: Core and Builtins<158>-Footnote-85540493
Ref: Core and Builtins<158>-Footnote-95540558
Ref: Core and Builtins<158>-Footnote-105540623
Ref: Core and Builtins<158>-Footnote-115540689
Ref: Core and Builtins<158>-Footnote-125540755
Ref: Core and Builtins<158>-Footnote-135540821
Ref: Core and Builtins<158>-Footnote-145540887
Ref: Core and Builtins<158>-Footnote-155540953
Ref: Core and Builtins<158>-Footnote-165541019
Ref: Core and Builtins<158>-Footnote-175541085
Ref: Core and Builtins<158>-Footnote-185541151
Ref: Core and Builtins<158>-Footnote-195541217
Ref: Core and Builtins<158>-Footnote-205541283
Ref: Core and Builtins<158>-Footnote-215541349
Ref: Core and Builtins<158>-Footnote-225541415
Ref: Core and Builtins<158>-Footnote-235541481
Node: Library<160>5541547
Ref: whatsnew/changelog id8705541666
Ref: 1cbb5541666
Ref: Library<160>-Footnote-15547456
Ref: Library<160>-Footnote-25547521
Ref: Library<160>-Footnote-35547586
Ref: Library<160>-Footnote-45547651
Ref: Library<160>-Footnote-55547716
Ref: Library<160>-Footnote-65547781
Ref: Library<160>-Footnote-75547846
Ref: Library<160>-Footnote-85547911
Ref: Library<160>-Footnote-95547976
Ref: Library<160>-Footnote-105548041
Ref: Library<160>-Footnote-115548107
Ref: Library<160>-Footnote-125548173
Ref: Library<160>-Footnote-135548239
Ref: Library<160>-Footnote-145548305
Ref: Library<160>-Footnote-155548371
Ref: Library<160>-Footnote-165548437
Ref: Library<160>-Footnote-175548503
Ref: Library<160>-Footnote-185548569
Ref: Library<160>-Footnote-195548635
Ref: Library<160>-Footnote-205548701
Ref: Library<160>-Footnote-215548767
Ref: Library<160>-Footnote-225548833
Ref: Library<160>-Footnote-235548899
Ref: Library<160>-Footnote-245548965
Ref: Library<160>-Footnote-255549031
Ref: Library<160>-Footnote-265549097
Ref: Library<160>-Footnote-275549163
Ref: Library<160>-Footnote-285549229
Ref: Library<160>-Footnote-295549295
Ref: Library<160>-Footnote-305549361
Ref: Library<160>-Footnote-315549427
Ref: Library<160>-Footnote-325549493
Ref: Library<160>-Footnote-335549559
Ref: Library<160>-Footnote-345549625
Ref: Library<160>-Footnote-355549691
Ref: Library<160>-Footnote-365549757
Ref: Library<160>-Footnote-375549823
Ref: Library<160>-Footnote-385549889
Ref: Library<160>-Footnote-395549955
Ref: Library<160>-Footnote-405550021
Ref: Library<160>-Footnote-415550087
Ref: Library<160>-Footnote-425550153
Ref: Library<160>-Footnote-435550219
Ref: Library<160>-Footnote-445550285
Ref: Library<160>-Footnote-455550351
Ref: Library<160>-Footnote-465550417
Ref: Library<160>-Footnote-475550483
Ref: Library<160>-Footnote-485550549
Node: Windows<70>5550615
Ref: whatsnew/changelog id8715550721
Ref: 1cbc5550721
Ref: Windows<70>-Footnote-15551532
Ref: Windows<70>-Footnote-25551597
Ref: Windows<70>-Footnote-35551662
Ref: Windows<70>-Footnote-45551727
Ref: Windows<70>-Footnote-55551792
Ref: Windows<70>-Footnote-65551857
Ref: Windows<70>-Footnote-75551922
Ref: Windows<70>-Footnote-85551987
Ref: Windows<70>-Footnote-95552052
Ref: Windows<70>-Footnote-105552117
Node: C API<69>5552183
Ref: whatsnew/changelog id8725552286
Ref: 1cbd5552286
Ref: C API<69>-Footnote-15552540
Node: Build<82>5552605
Ref: whatsnew/changelog id8735552706
Ref: 1cbe5552706
Ref: Build<82>-Footnote-15553132
Ref: Build<82>-Footnote-25553197
Ref: Build<82>-Footnote-35553262
Node: Tests<74>5553327
Ref: whatsnew/changelog id8745553410
Ref: 1cbf5553410
Ref: Tests<74>-Footnote-15553547
Node: Python 3 6 0 beta 15553612
Ref: whatsnew/changelog python-3-6-0-beta-15553734
Ref: 1cc05553734
Node: Core and Builtins<159>5554033
Ref: whatsnew/changelog id8755554132
Ref: 1cc15554132
Ref: Core and Builtins<159>-Footnote-15560331
Ref: Core and Builtins<159>-Footnote-25560396
Ref: Core and Builtins<159>-Footnote-35560461
Ref: Core and Builtins<159>-Footnote-45560526
Ref: Core and Builtins<159>-Footnote-55560568
Ref: Core and Builtins<159>-Footnote-65560633
Ref: Core and Builtins<159>-Footnote-75560698
Ref: Core and Builtins<159>-Footnote-85560763
Ref: Core and Builtins<159>-Footnote-95560828
Ref: Core and Builtins<159>-Footnote-105560893
Ref: Core and Builtins<159>-Footnote-115560959
Ref: Core and Builtins<159>-Footnote-125561025
Ref: Core and Builtins<159>-Footnote-135561091
Ref: Core and Builtins<159>-Footnote-145561134
Ref: Core and Builtins<159>-Footnote-155561200
Ref: Core and Builtins<159>-Footnote-165561266
Ref: Core and Builtins<159>-Footnote-175561309
Ref: Core and Builtins<159>-Footnote-185561375
Ref: Core and Builtins<159>-Footnote-195561418
Ref: Core and Builtins<159>-Footnote-205561484
Ref: Core and Builtins<159>-Footnote-215561550
Ref: Core and Builtins<159>-Footnote-225561616
Ref: Core and Builtins<159>-Footnote-235561682
Ref: Core and Builtins<159>-Footnote-245561748
Ref: Core and Builtins<159>-Footnote-255561814
Ref: Core and Builtins<159>-Footnote-265561880
Ref: Core and Builtins<159>-Footnote-275561946
Ref: Core and Builtins<159>-Footnote-285561989
Ref: Core and Builtins<159>-Footnote-295562055
Ref: Core and Builtins<159>-Footnote-305562121
Ref: Core and Builtins<159>-Footnote-315562187
Ref: Core and Builtins<159>-Footnote-325562253
Ref: Core and Builtins<159>-Footnote-335562319
Ref: Core and Builtins<159>-Footnote-345562385
Ref: Core and Builtins<159>-Footnote-355562451
Ref: Core and Builtins<159>-Footnote-365562517
Ref: Core and Builtins<159>-Footnote-375562583
Ref: Core and Builtins<159>-Footnote-385562649
Ref: Core and Builtins<159>-Footnote-395562715
Ref: Core and Builtins<159>-Footnote-405562781
Ref: Core and Builtins<159>-Footnote-415562847
Ref: Core and Builtins<159>-Footnote-425562913
Ref: Core and Builtins<159>-Footnote-435562979
Ref: Core and Builtins<159>-Footnote-445563045
Ref: Core and Builtins<159>-Footnote-455563111
Ref: Core and Builtins<159>-Footnote-465563177
Ref: Core and Builtins<159>-Footnote-475563220
Node: Library<161>5563286
Ref: whatsnew/changelog id8765563402
Ref: 1cc25563402
Ref: Library<161>-Footnote-15574394
Ref: Library<161>-Footnote-25574459
Ref: Library<161>-Footnote-35574524
Ref: Library<161>-Footnote-45574589
Ref: Library<161>-Footnote-55574654
Ref: Library<161>-Footnote-65574719
Ref: Library<161>-Footnote-75574784
Ref: Library<161>-Footnote-85574849
Ref: Library<161>-Footnote-95574914
Ref: Library<161>-Footnote-105574979
Ref: Library<161>-Footnote-115575045
Ref: Library<161>-Footnote-125575111
Ref: Library<161>-Footnote-135575177
Ref: Library<161>-Footnote-145575243
Ref: Library<161>-Footnote-155575309
Ref: Library<161>-Footnote-165575375
Ref: Library<161>-Footnote-175575441
Ref: Library<161>-Footnote-185575509
Ref: Library<161>-Footnote-195575575
Ref: Library<161>-Footnote-205575641
Ref: Library<161>-Footnote-215575707
Ref: Library<161>-Footnote-225575773
Ref: Library<161>-Footnote-235575839
Ref: Library<161>-Footnote-245575905
Ref: Library<161>-Footnote-255575971
Ref: Library<161>-Footnote-265576038
Ref: Library<161>-Footnote-275576104
Ref: Library<161>-Footnote-285576170
Ref: Library<161>-Footnote-295576236
Ref: Library<161>-Footnote-305576302
Ref: Library<161>-Footnote-315576368
Ref: Library<161>-Footnote-325576434
Ref: Library<161>-Footnote-335576500
Ref: Library<161>-Footnote-345576566
Ref: Library<161>-Footnote-355576632
Ref: Library<161>-Footnote-365576698
Ref: Library<161>-Footnote-375576764
Ref: Library<161>-Footnote-385576830
Ref: Library<161>-Footnote-395576896
Ref: Library<161>-Footnote-405576962
Ref: Library<161>-Footnote-415577028
Ref: Library<161>-Footnote-425577094
Ref: Library<161>-Footnote-435577137
Ref: Library<161>-Footnote-445577203
Ref: Library<161>-Footnote-455577246
Ref: Library<161>-Footnote-465577312
Ref: Library<161>-Footnote-475577378
Ref: Library<161>-Footnote-485577444
Ref: Library<161>-Footnote-495577510
Ref: Library<161>-Footnote-505577576
Ref: Library<161>-Footnote-515577642
Ref: Library<161>-Footnote-525577708
Ref: Library<161>-Footnote-535577774
Ref: Library<161>-Footnote-545577830
Ref: Library<161>-Footnote-555577896
Ref: Library<161>-Footnote-565577962
Ref: Library<161>-Footnote-575578028
Ref: Library<161>-Footnote-585578094
Ref: Library<161>-Footnote-595578160
Ref: Library<161>-Footnote-605578226
Ref: Library<161>-Footnote-615578292
Ref: Library<161>-Footnote-625578358
Ref: Library<161>-Footnote-635578424
Ref: Library<161>-Footnote-645578490
Ref: Library<161>-Footnote-655578556
Ref: Library<161>-Footnote-665578622
Ref: Library<161>-Footnote-675578688
Ref: Library<161>-Footnote-685578754
Ref: Library<161>-Footnote-695578820
Ref: Library<161>-Footnote-705578886
Ref: Library<161>-Footnote-715578952
Ref: Library<161>-Footnote-725579018
Ref: Library<161>-Footnote-735579084
Ref: Library<161>-Footnote-745579150
Ref: Library<161>-Footnote-755579216
Ref: Library<161>-Footnote-765579282
Ref: Library<161>-Footnote-775579347
Ref: Library<161>-Footnote-785579412
Ref: Library<161>-Footnote-795579478
Ref: Library<161>-Footnote-805579544
Ref: Library<161>-Footnote-815579609
Ref: Library<161>-Footnote-825579675
Node: IDLE<56>5579741
Ref: whatsnew/changelog id8775579844
Ref: 1cc35579844
Ref: IDLE<56>-Footnote-15580610
Ref: IDLE<56>-Footnote-25580675
Ref: IDLE<56>-Footnote-35580740
Ref: IDLE<56>-Footnote-45580805
Ref: IDLE<56>-Footnote-55580870
Ref: IDLE<56>-Footnote-65580935
Node: C API<70>5581000
Ref: whatsnew/changelog id8785581100
Ref: 1cc45581100
Ref: C API<70>-Footnote-15581372
Ref: C API<70>-Footnote-25581437
Node: Tests<75>5581502
Ref: whatsnew/changelog id8795581603
Ref: 1cc55581603
Ref: Tests<75>-Footnote-15582123
Ref: Tests<75>-Footnote-25582188
Ref: Tests<75>-Footnote-35582253
Ref: Tests<75>-Footnote-45582318
Node: Build<83>5582383
Ref: whatsnew/changelog id8805582490
Ref: 1cc65582490
Ref: Build<83>-Footnote-15583875
Ref: Build<83>-Footnote-25583940
Ref: Build<83>-Footnote-35584005
Ref: Build<83>-Footnote-45584070
Ref: Build<83>-Footnote-55584135
Ref: Build<83>-Footnote-65584200
Ref: Build<83>-Footnote-75584265
Ref: Build<83>-Footnote-85584330
Ref: Build<83>-Footnote-95584395
Ref: Build<83>-Footnote-105584460
Ref: Build<83>-Footnote-115584526
Node: Tools/Demos<44>5584592
Ref: whatsnew/changelog id8815584701
Ref: 1cc75584701
Ref: Tools/Demos<44>-Footnote-15584980
Node: Windows<71>5585045
Ref: whatsnew/changelog id8825585136
Ref: 1cc85585136
Ref: Windows<71>-Footnote-15586105
Ref: Windows<71>-Footnote-25586170
Ref: Windows<71>-Footnote-35586235
Ref: Windows<71>-Footnote-45586299
Ref: Windows<71>-Footnote-55586364
Ref: Windows<71>-Footnote-65586429
Ref: Windows<71>-Footnote-75586493
Ref: Windows<71>-Footnote-85586558
Ref: Windows<71>-Footnote-95586623
Ref: Windows<71>-Footnote-105586688
Ref: Windows<71>-Footnote-115586754
Node: Python 3 6 0 alpha 45586820
Ref: whatsnew/changelog python-3-6-0-alpha-45586943
Ref: 1cc95586943
Node: Core and Builtins<160>5587192
Ref: whatsnew/changelog id8835587292
Ref: 1cca5587292
Ref: Core and Builtins<160>-Footnote-15589250
Ref: Core and Builtins<160>-Footnote-25589315
Ref: Core and Builtins<160>-Footnote-35589380
Ref: Core and Builtins<160>-Footnote-45589445
Ref: Core and Builtins<160>-Footnote-55589510
Ref: Core and Builtins<160>-Footnote-65589575
Ref: Core and Builtins<160>-Footnote-75589640
Ref: Core and Builtins<160>-Footnote-85589705
Ref: Core and Builtins<160>-Footnote-95589770
Ref: Core and Builtins<160>-Footnote-105589834
Ref: Core and Builtins<160>-Footnote-115589900
Ref: Core and Builtins<160>-Footnote-125589966
Ref: Core and Builtins<160>-Footnote-135590032
Ref: Core and Builtins<160>-Footnote-145590098
Node: Library<162>5590141
Ref: whatsnew/changelog id8845590258
Ref: 1ccb5590258
Ref: Library<162>-Footnote-15594771
Ref: Library<162>-Footnote-25594836
Ref: Library<162>-Footnote-35594878
Ref: Library<162>-Footnote-45594943
Ref: Library<162>-Footnote-55595008
Ref: Library<162>-Footnote-65595073
Ref: Library<162>-Footnote-75595138
Ref: Library<162>-Footnote-85595203
Ref: Library<162>-Footnote-95595268
Ref: Library<162>-Footnote-105595333
Ref: Library<162>-Footnote-115595399
Ref: Library<162>-Footnote-125595442
Ref: Library<162>-Footnote-135595508
Ref: Library<162>-Footnote-145595574
Ref: Library<162>-Footnote-155595640
Ref: Library<162>-Footnote-165595706
Ref: Library<162>-Footnote-175595771
Ref: Library<162>-Footnote-185595837
Ref: Library<162>-Footnote-195595903
Ref: Library<162>-Footnote-205595969
Ref: Library<162>-Footnote-215596035
Ref: Library<162>-Footnote-225596101
Ref: Library<162>-Footnote-235596167
Ref: Library<162>-Footnote-245596233
Ref: Library<162>-Footnote-255596299
Ref: Library<162>-Footnote-265596365
Ref: Library<162>-Footnote-275596431
Ref: Library<162>-Footnote-285596497
Ref: Library<162>-Footnote-295596556
Ref: Library<162>-Footnote-305596621
Ref: Library<162>-Footnote-315596687
Ref: Library<162>-Footnote-325596753
Ref: Library<162>-Footnote-335596819
Ref: Library<162>-Footnote-345596862
Ref: Library<162>-Footnote-355596928
Ref: Library<162>-Footnote-365596993
Ref: Library<162>-Footnote-375597059
Ref: Library<162>-Footnote-385597125
Ref: Library<162>-Footnote-395597191
Node: IDLE<57>5597257
Ref: whatsnew/changelog id8855597361
Ref: 1ccc5597361
Ref: IDLE<57>-Footnote-15598685
Ref: IDLE<57>-Footnote-25598750
Ref: IDLE<57>-Footnote-35598815
Ref: IDLE<57>-Footnote-45598880
Ref: IDLE<57>-Footnote-55598945
Ref: IDLE<57>-Footnote-65599010
Ref: IDLE<57>-Footnote-75599075
Ref: IDLE<57>-Footnote-85599140
Node: Tests<76>5599205
Ref: whatsnew/changelog id8865599308
Ref: 1ccd5599308
Ref: Tests<76>-Footnote-15599897
Ref: Tests<76>-Footnote-25599962
Ref: Tests<76>-Footnote-35600027
Ref: Tests<76>-Footnote-45600092
Node: Windows<72>5600157
Ref: whatsnew/changelog id8875600261
Ref: 1cce5600261
Ref: Windows<72>-Footnote-15600637
Ref: Windows<72>-Footnote-25600702
Ref: Windows<72>-Footnote-35600767
Ref: Windows<72>-Footnote-45600809
Ref: Windows<72>-Footnote-55600874
Node: Build<84>5600939
Ref: whatsnew/changelog id8885601025
Ref: 1ccf5601025
Ref: Build<84>-Footnote-15601926
Ref: Build<84>-Footnote-25601991
Ref: Build<84>-Footnote-35602056
Ref: Build<84>-Footnote-45602121
Ref: Build<84>-Footnote-55602186
Ref: Build<84>-Footnote-65602251
Node: Python 3 6 0 alpha 35602316
Ref: whatsnew/changelog python-3-6-0-alpha-35602440
Ref: 1cd05602440
Node: Security<51>5602779
Ref: whatsnew/changelog id8895602879
Ref: 1cd15602879
Ref: Security<51>-Footnote-15603257
Ref: Security<51>-Footnote-25603322
Node: Core and Builtins<161>5603387
Ref: whatsnew/changelog id8905603508
Ref: 1cd25603508
Ref: Core and Builtins<161>-Footnote-15604259
Ref: Core and Builtins<161>-Footnote-25604324
Ref: Core and Builtins<161>-Footnote-35604389
Ref: Core and Builtins<161>-Footnote-45604454
Node: Library<163>5604519
Ref: whatsnew/changelog id8915604636
Ref: 1cd35604636
Ref: Library<163>-Footnote-15608749
Ref: Library<163>-Footnote-25608814
Ref: Library<163>-Footnote-35608879
Ref: Library<163>-Footnote-45608944
Ref: Library<163>-Footnote-55609009
Ref: Library<163>-Footnote-65609074
Ref: Library<163>-Footnote-75609139
Ref: Library<163>-Footnote-85609204
Ref: Library<163>-Footnote-95609269
Ref: Library<163>-Footnote-105609334
Ref: Library<163>-Footnote-115609400
Ref: Library<163>-Footnote-125609466
Ref: Library<163>-Footnote-135609532
Ref: Library<163>-Footnote-145609598
Ref: Library<163>-Footnote-155609664
Ref: Library<163>-Footnote-165609730
Ref: Library<163>-Footnote-175609796
Ref: Library<163>-Footnote-185609862
Ref: Library<163>-Footnote-195609928
Ref: Library<163>-Footnote-205609994
Ref: Library<163>-Footnote-215610060
Ref: Library<163>-Footnote-225610103
Ref: Library<163>-Footnote-235610169
Ref: Library<163>-Footnote-245610235
Ref: Library<163>-Footnote-255610300
Ref: Library<163>-Footnote-265610366
Node: IDLE<58>5610432
Ref: whatsnew/changelog id8925610536
Ref: 1cd45610536
Ref: IDLE<58>-Footnote-15612202
Ref: IDLE<58>-Footnote-25612267
Ref: IDLE<58>-Footnote-35612332
Ref: IDLE<58>-Footnote-45612397
Ref: IDLE<58>-Footnote-55612462
Ref: IDLE<58>-Footnote-65612527
Ref: IDLE<58>-Footnote-75612592
Ref: IDLE<58>-Footnote-85612657
Ref: IDLE<58>-Footnote-95612722
Ref: IDLE<58>-Footnote-105612787
Node: C API<71>5612853
Ref: whatsnew/changelog id8935612954
Ref: 1cd55612954
Ref: C API<71>-Footnote-15613194
Node: Build<85>5613259
Ref: whatsnew/changelog id8945613367
Ref: 1cd65613367
Ref: Build<85>-Footnote-15614344
Ref: Build<85>-Footnote-25614409
Ref: Build<85>-Footnote-35614474
Ref: Build<85>-Footnote-45614539
Ref: Build<85>-Footnote-55614604
Node: Tools/Demos<45>5614669
Ref: whatsnew/changelog id8955614785
Ref: 1cd75614785
Ref: Tools/Demos<45>-Footnote-15615069
Ref: Tools/Demos<45>-Footnote-25615134
Node: Documentation<73>5615199
Ref: whatsnew/changelog id8965615315
Ref: 1cd85615315
Ref: Documentation<73>-Footnote-15615696
Ref: Documentation<73>-Footnote-25615761
Node: Tests<77>5615826
Ref: whatsnew/changelog id8975615918
Ref: 1cd95615918
Ref: Tests<77>-Footnote-15616086
Node: Python 3 6 0 alpha 25616151
Ref: whatsnew/changelog python-3-6-0-alpha-25616275
Ref: 1cda5616275
Node: Security<52>5616638
Ref: whatsnew/changelog id8985616738
Ref: 1cdb5616738
Ref: Security<52>-Footnote-15617229
Ref: Security<52>-Footnote-25617294
Ref: Security<52>-Footnote-35617349
Ref: Security<52>-Footnote-45617404
Node: Core and Builtins<162>5617469
Ref: whatsnew/changelog id8995617590
Ref: 1cdc5617590
Ref: Core and Builtins<162>-Footnote-15619222
Ref: Core and Builtins<162>-Footnote-25619287
Ref: Core and Builtins<162>-Footnote-35619352
Ref: Core and Builtins<162>-Footnote-45619417
Ref: Core and Builtins<162>-Footnote-55619482
Ref: Core and Builtins<162>-Footnote-65619547
Ref: Core and Builtins<162>-Footnote-75619589
Ref: Core and Builtins<162>-Footnote-85619654
Ref: Core and Builtins<162>-Footnote-95619719
Ref: Core and Builtins<162>-Footnote-105619784
Ref: Core and Builtins<162>-Footnote-115619850
Ref: Core and Builtins<162>-Footnote-125619916
Node: Library<164>5619982
Ref: whatsnew/changelog id9005620099
Ref: 1cdd5620099
Ref: Library<164>-Footnote-15625310
Ref: Library<164>-Footnote-25625375
Ref: Library<164>-Footnote-35625440
Ref: Library<164>-Footnote-45625505
Ref: Library<164>-Footnote-55625570
Ref: Library<164>-Footnote-65625635
Ref: Library<164>-Footnote-75625700
Ref: Library<164>-Footnote-85625765
Ref: Library<164>-Footnote-95625830
Ref: Library<164>-Footnote-105625872
Ref: Library<164>-Footnote-115625938
Ref: Library<164>-Footnote-125626004
Ref: Library<164>-Footnote-135626070
Ref: Library<164>-Footnote-145626113
Ref: Library<164>-Footnote-155626179
Ref: Library<164>-Footnote-165626222
Ref: Library<164>-Footnote-175626265
Ref: Library<164>-Footnote-185626331
Ref: Library<164>-Footnote-195626397
Ref: Library<164>-Footnote-205626463
Ref: Library<164>-Footnote-215626529
Ref: Library<164>-Footnote-225626595
Ref: Library<164>-Footnote-235626661
Ref: Library<164>-Footnote-245626727
Ref: Library<164>-Footnote-255626793
Ref: Library<164>-Footnote-265626859
Ref: Library<164>-Footnote-275626925
Ref: Library<164>-Footnote-285626991
Ref: Library<164>-Footnote-295627057
Ref: Library<164>-Footnote-305627123
Ref: Library<164>-Footnote-315627189
Ref: Library<164>-Footnote-325627255
Ref: Library<164>-Footnote-335627321
Ref: Library<164>-Footnote-345627387
Ref: Library<164>-Footnote-355627453
Node: IDLE<59>5627519
Ref: whatsnew/changelog id9015627631
Ref: 1cde5627631
Ref: IDLE<59>-Footnote-15630284
Ref: IDLE<59>-Footnote-25630348
Ref: IDLE<59>-Footnote-35630413
Ref: IDLE<59>-Footnote-45630478
Ref: IDLE<59>-Footnote-55630543
Ref: IDLE<59>-Footnote-65630608
Ref: IDLE<59>-Footnote-75630673
Ref: IDLE<59>-Footnote-85630738
Ref: IDLE<59>-Footnote-95630803
Ref: IDLE<59>-Footnote-105630868
Ref: IDLE<59>-Footnote-115630934
Ref: IDLE<59>-Footnote-125631000
Ref: IDLE<59>-Footnote-135631066
Ref: IDLE<59>-Footnote-145631132
Ref: IDLE<59>-Footnote-155631198
Ref: IDLE<59>-Footnote-165631264
Ref: IDLE<59>-Footnote-175631330
Ref: IDLE<59>-Footnote-185631396
Ref: IDLE<59>-Footnote-195631462
Node: Documentation<74>5631528
Ref: whatsnew/changelog id9025631637
Ref: 1cdf5631637
Ref: Documentation<74>-Footnote-15632084
Ref: Documentation<74>-Footnote-25632149
Ref: Documentation<74>-Footnote-35632214
Ref: Documentation<74>-Footnote-45632256
Node: Tests<78>5632321
Ref: whatsnew/changelog id9035632433
Ref: 1ce05632433
Ref: Tests<78>-Footnote-15632813
Ref: Tests<78>-Footnote-25632878
Node: Windows<73>5632943
Ref: whatsnew/changelog id9045633047
Ref: 1ce15633047
Ref: Windows<73>-Footnote-15633457
Ref: Windows<73>-Footnote-25633522
Node: Build<86>5633587
Ref: whatsnew/changelog id9055633691
Ref: 1ce25633691
Ref: Build<86>-Footnote-15633968
Ref: Build<86>-Footnote-25634033
Node: C API<72>5634098
Ref: whatsnew/changelog id9065634206
Ref: 1ce35634206
Ref: C API<72>-Footnote-15634444
Ref: C API<72>-Footnote-25634509
Ref: C API<72>-Footnote-35634551
Node: Tools/Demos<46>5634616
Ref: whatsnew/changelog id9075634706
Ref: 1ce45634706
Ref: Tools/Demos<46>-Footnote-15634904
Node: Python 3 6 0 alpha 15634969
Ref: whatsnew/changelog python-3-6-0-alpha-15635091
Ref: 1ce55635091
Node: Security<53>5635454
Ref: whatsnew/changelog id9085635554
Ref: 1ce65635554
Ref: Security<53>-Footnote-15636045
Ref: Security<53>-Footnote-25636110
Ref: Security<53>-Footnote-35636175
Node: Core and Builtins<163>5636240
Ref: whatsnew/changelog id9095636361
Ref: 1ce75636361
Ref: Core and Builtins<163>-Footnote-15649547
Ref: Core and Builtins<163>-Footnote-25649612
Ref: Core and Builtins<163>-Footnote-35649677
Ref: Core and Builtins<163>-Footnote-45649742
Ref: Core and Builtins<163>-Footnote-55649807
Ref: Core and Builtins<163>-Footnote-65649872
Ref: Core and Builtins<163>-Footnote-75649937
Ref: Core and Builtins<163>-Footnote-85650002
Ref: Core and Builtins<163>-Footnote-95650067
Ref: Core and Builtins<163>-Footnote-105650132
Ref: Core and Builtins<163>-Footnote-115650198
Ref: Core and Builtins<163>-Footnote-125650264
Ref: Core and Builtins<163>-Footnote-135650330
Ref: Core and Builtins<163>-Footnote-145650396
Ref: Core and Builtins<163>-Footnote-155650462
Ref: Core and Builtins<163>-Footnote-165650528
Ref: Core and Builtins<163>-Footnote-175650571
Ref: Core and Builtins<163>-Footnote-185650637
Ref: Core and Builtins<163>-Footnote-195650703
Ref: Core and Builtins<163>-Footnote-205650769
Ref: Core and Builtins<163>-Footnote-215650835
Ref: Core and Builtins<163>-Footnote-225650901
Ref: Core and Builtins<163>-Footnote-235650967
Ref: Core and Builtins<163>-Footnote-245651010
Ref: Core and Builtins<163>-Footnote-255651076
Ref: Core and Builtins<163>-Footnote-265651142
Ref: Core and Builtins<163>-Footnote-275651208
Ref: Core and Builtins<163>-Footnote-285651274
Ref: Core and Builtins<163>-Footnote-295651340
Ref: Core and Builtins<163>-Footnote-305651406
Ref: Core and Builtins<163>-Footnote-315651472
Ref: Core and Builtins<163>-Footnote-325651538
Ref: Core and Builtins<163>-Footnote-335651604
Ref: Core and Builtins<163>-Footnote-345651670
Ref: Core and Builtins<163>-Footnote-355651736
Ref: Core and Builtins<163>-Footnote-365651802
Ref: Core and Builtins<163>-Footnote-375651867
Ref: Core and Builtins<163>-Footnote-385651933
Ref: Core and Builtins<163>-Footnote-395651999
Ref: Core and Builtins<163>-Footnote-405652065
Ref: Core and Builtins<163>-Footnote-415652131
Ref: Core and Builtins<163>-Footnote-425652197
Ref: Core and Builtins<163>-Footnote-435652263
Ref: Core and Builtins<163>-Footnote-445652329
Ref: Core and Builtins<163>-Footnote-455652395
Ref: Core and Builtins<163>-Footnote-465652461
Ref: Core and Builtins<163>-Footnote-475652527
Ref: Core and Builtins<163>-Footnote-485652593
Ref: Core and Builtins<163>-Footnote-495652659
Ref: Core and Builtins<163>-Footnote-505652725
Ref: Core and Builtins<163>-Footnote-515652791
Ref: Core and Builtins<163>-Footnote-525652857
Ref: Core and Builtins<163>-Footnote-535652922
Ref: Core and Builtins<163>-Footnote-545652988
Ref: Core and Builtins<163>-Footnote-555653054
Ref: Core and Builtins<163>-Footnote-565653120
Ref: Core and Builtins<163>-Footnote-575653186
Ref: Core and Builtins<163>-Footnote-585653252
Ref: Core and Builtins<163>-Footnote-595653318
Ref: Core and Builtins<163>-Footnote-605653384
Ref: Core and Builtins<163>-Footnote-615653450
Ref: Core and Builtins<163>-Footnote-625653516
Ref: Core and Builtins<163>-Footnote-635653582
Ref: Core and Builtins<163>-Footnote-645653648
Ref: Core and Builtins<163>-Footnote-655653714
Ref: Core and Builtins<163>-Footnote-665653780
Ref: Core and Builtins<163>-Footnote-675653846
Ref: Core and Builtins<163>-Footnote-685653912
Ref: Core and Builtins<163>-Footnote-695653978
Ref: Core and Builtins<163>-Footnote-705654044
Ref: Core and Builtins<163>-Footnote-715654110
Ref: Core and Builtins<163>-Footnote-725654176
Ref: Core and Builtins<163>-Footnote-735654242
Ref: Core and Builtins<163>-Footnote-745654308
Ref: Core and Builtins<163>-Footnote-755654374
Ref: Core and Builtins<163>-Footnote-765654440
Ref: Core and Builtins<163>-Footnote-775654506
Ref: Core and Builtins<163>-Footnote-785654572
Ref: Core and Builtins<163>-Footnote-795654637
Ref: Core and Builtins<163>-Footnote-805654703
Ref: Core and Builtins<163>-Footnote-815654746
Ref: Core and Builtins<163>-Footnote-825654812
Ref: Core and Builtins<163>-Footnote-835654878
Ref: Core and Builtins<163>-Footnote-845654944
Ref: Core and Builtins<163>-Footnote-855655010
Ref: Core and Builtins<163>-Footnote-865655076
Ref: Core and Builtins<163>-Footnote-875655142
Node: Library<165>5655208
Ref: whatsnew/changelog id9105655325
Ref: 1ce95655325
Ref: Library<165>-Footnote-15686395
Ref: Library<165>-Footnote-25686460
Ref: Library<165>-Footnote-35686525
Ref: Library<165>-Footnote-45686590
Ref: Library<165>-Footnote-55686655
Ref: Library<165>-Footnote-65686720
Ref: Library<165>-Footnote-75686785
Ref: Library<165>-Footnote-85686850
Ref: Library<165>-Footnote-95686915
Ref: Library<165>-Footnote-105686980
Ref: Library<165>-Footnote-115687046
Ref: Library<165>-Footnote-125687112
Ref: Library<165>-Footnote-135687178
Ref: Library<165>-Footnote-145687244
Ref: Library<165>-Footnote-155687310
Ref: Library<165>-Footnote-165687376
Ref: Library<165>-Footnote-175687442
Ref: Library<165>-Footnote-185687508
Ref: Library<165>-Footnote-195687551
Ref: Library<165>-Footnote-205687617
Ref: Library<165>-Footnote-215687683
Ref: Library<165>-Footnote-225687749
Ref: Library<165>-Footnote-235687815
Ref: Library<165>-Footnote-245687881
Ref: Library<165>-Footnote-255687947
Ref: Library<165>-Footnote-265688013
Ref: Library<165>-Footnote-275688079
Ref: Library<165>-Footnote-285688145
Ref: Library<165>-Footnote-295688211
Ref: Library<165>-Footnote-305688277
Ref: Library<165>-Footnote-315688343
Ref: Library<165>-Footnote-325688409
Ref: Library<165>-Footnote-335688475
Ref: Library<165>-Footnote-345688541
Ref: Library<165>-Footnote-355688607
Ref: Library<165>-Footnote-365688673
Ref: Library<165>-Footnote-375688739
Ref: Library<165>-Footnote-385688805
Ref: Library<165>-Footnote-395688871
Ref: Library<165>-Footnote-405688937
Ref: Library<165>-Footnote-415689003
Ref: Library<165>-Footnote-425689069
Ref: Library<165>-Footnote-435689135
Ref: Library<165>-Footnote-445689201
Ref: Library<165>-Footnote-455689267
Ref: Library<165>-Footnote-465689333
Ref: Library<165>-Footnote-475689399
Ref: Library<165>-Footnote-485689465
Ref: Library<165>-Footnote-495689531
Ref: Library<165>-Footnote-505689597
Ref: Library<165>-Footnote-515689663
Ref: Library<165>-Footnote-525689729
Ref: Library<165>-Footnote-535689795
Ref: Library<165>-Footnote-545689861
Ref: Library<165>-Footnote-555689927
Ref: Library<165>-Footnote-565689993
Ref: Library<165>-Footnote-575690059
Ref: Library<165>-Footnote-585690125
Ref: Library<165>-Footnote-595690191
Ref: Library<165>-Footnote-605690257
Ref: Library<165>-Footnote-615690323
Ref: Library<165>-Footnote-625690389
Ref: Library<165>-Footnote-635690455
Ref: Library<165>-Footnote-645690521
Ref: Library<165>-Footnote-655690587
Ref: Library<165>-Footnote-665690653
Ref: Library<165>-Footnote-675690719
Ref: Library<165>-Footnote-685690785
Ref: Library<165>-Footnote-695690851
Ref: Library<165>-Footnote-705690917
Ref: Library<165>-Footnote-715690983
Ref: Library<165>-Footnote-725691049
Ref: Library<165>-Footnote-735691115
Ref: Library<165>-Footnote-745691181
Ref: Library<165>-Footnote-755691247
Ref: Library<165>-Footnote-765691313
Ref: Library<165>-Footnote-775691379
Ref: Library<165>-Footnote-785691445
Ref: Library<165>-Footnote-795691511
Ref: Library<165>-Footnote-805691577
Ref: Library<165>-Footnote-815691642
Ref: Library<165>-Footnote-825691708
Ref: Library<165>-Footnote-835691774
Ref: Library<165>-Footnote-845691840
Ref: Library<165>-Footnote-855691906
Ref: Library<165>-Footnote-865691972
Ref: Library<165>-Footnote-875692038
Ref: Library<165>-Footnote-885692104
Ref: Library<165>-Footnote-895692170
Ref: Library<165>-Footnote-905692236
Ref: Library<165>-Footnote-915692302
Ref: Library<165>-Footnote-925692368
Ref: Library<165>-Footnote-935692434
Ref: Library<165>-Footnote-945692500
Ref: Library<165>-Footnote-955692566
Ref: Library<165>-Footnote-965692632
Ref: Library<165>-Footnote-975692698
Ref: Library<165>-Footnote-985692764
Ref: Library<165>-Footnote-995692830
Ref: Library<165>-Footnote-1005692896
Ref: Library<165>-Footnote-1015692963
Ref: Library<165>-Footnote-1025693030
Ref: Library<165>-Footnote-1035693097
Ref: Library<165>-Footnote-1045693164
Ref: Library<165>-Footnote-1055693231
Ref: Library<165>-Footnote-1065693298
Ref: Library<165>-Footnote-1075693365
Ref: Library<165>-Footnote-1085693432
Ref: Library<165>-Footnote-1095693499
Ref: Library<165>-Footnote-1105693566
Ref: Library<165>-Footnote-1115693633
Ref: Library<165>-Footnote-1125693700
Ref: Library<165>-Footnote-1135693767
Ref: Library<165>-Footnote-1145693834
Ref: Library<165>-Footnote-1155693901
Ref: Library<165>-Footnote-1165693968
Ref: Library<165>-Footnote-1175694035
Ref: Library<165>-Footnote-1185694102
Ref: Library<165>-Footnote-1195694169
Ref: Library<165>-Footnote-1205694236
Ref: Library<165>-Footnote-1215694303
Ref: Library<165>-Footnote-1225694370
Ref: Library<165>-Footnote-1235694437
Ref: Library<165>-Footnote-1245694504
Ref: Library<165>-Footnote-1255694571
Ref: Library<165>-Footnote-1265694638
Ref: Library<165>-Footnote-1275694705
Ref: Library<165>-Footnote-1285694772
Ref: Library<165>-Footnote-1295694839
Ref: Library<165>-Footnote-1305694906
Ref: Library<165>-Footnote-1315694973
Ref: Library<165>-Footnote-1325695040
Ref: Library<165>-Footnote-1335695107
Ref: Library<165>-Footnote-1345695174
Ref: Library<165>-Footnote-1355695241
Ref: Library<165>-Footnote-1365695308
Ref: Library<165>-Footnote-1375695375
Ref: Library<165>-Footnote-1385695442
Ref: Library<165>-Footnote-1395695509
Ref: Library<165>-Footnote-1405695576
Ref: Library<165>-Footnote-1415695643
Ref: Library<165>-Footnote-1425695710
Ref: Library<165>-Footnote-1435695777
Ref: Library<165>-Footnote-1445695844
Ref: Library<165>-Footnote-1455695910
Ref: Library<165>-Footnote-1465695977
Ref: Library<165>-Footnote-1475696044
Ref: Library<165>-Footnote-1485696111
Ref: Library<165>-Footnote-1495696178
Ref: Library<165>-Footnote-1505696245
Ref: Library<165>-Footnote-1515696311
Ref: Library<165>-Footnote-1525696378
Ref: Library<165>-Footnote-1535696445
Ref: Library<165>-Footnote-1545696512
Ref: Library<165>-Footnote-1555696579
Ref: Library<165>-Footnote-1565696646
Ref: Library<165>-Footnote-1575696713
Ref: Library<165>-Footnote-1585696780
Ref: Library<165>-Footnote-1595696847
Ref: Library<165>-Footnote-1605696914
Ref: Library<165>-Footnote-1615696980
Ref: Library<165>-Footnote-1625697047
Ref: Library<165>-Footnote-1635697114
Ref: Library<165>-Footnote-1645697181
Ref: Library<165>-Footnote-1655697248
Ref: Library<165>-Footnote-1665697315
Ref: Library<165>-Footnote-1675697382
Ref: Library<165>-Footnote-1685697449
Ref: Library<165>-Footnote-1695697516
Ref: Library<165>-Footnote-1705697583
Ref: Library<165>-Footnote-1715697650
Ref: Library<165>-Footnote-1725697717
Ref: Library<165>-Footnote-1735697784
Ref: Library<165>-Footnote-1745697851
Ref: Library<165>-Footnote-1755697918
Ref: Library<165>-Footnote-1765697985
Ref: Library<165>-Footnote-1775698052
Ref: Library<165>-Footnote-1785698119
Ref: Library<165>-Footnote-1795698186
Ref: Library<165>-Footnote-1805698253
Ref: Library<165>-Footnote-1815698320
Ref: Library<165>-Footnote-1825698387
Ref: Library<165>-Footnote-1835698454
Ref: Library<165>-Footnote-1845698521
Ref: Library<165>-Footnote-1855698588
Ref: Library<165>-Footnote-1865698655
Ref: Library<165>-Footnote-1875698722
Ref: Library<165>-Footnote-1885698789
Ref: Library<165>-Footnote-1895698856
Ref: Library<165>-Footnote-1905698923
Ref: Library<165>-Footnote-1915698990
Ref: Library<165>-Footnote-1925699057
Ref: Library<165>-Footnote-1935699124
Ref: Library<165>-Footnote-1945699191
Ref: Library<165>-Footnote-1955699258
Ref: Library<165>-Footnote-1965699325
Ref: Library<165>-Footnote-1975699392
Ref: Library<165>-Footnote-1985699459
Ref: Library<165>-Footnote-1995699526
Ref: Library<165>-Footnote-2005699593
Ref: Library<165>-Footnote-2015699660
Ref: Library<165>-Footnote-2025699727
Ref: Library<165>-Footnote-2035699794
Ref: Library<165>-Footnote-2045699861
Ref: Library<165>-Footnote-2055699928
Ref: Library<165>-Footnote-2065699995
Ref: Library<165>-Footnote-2075700062
Ref: Library<165>-Footnote-2085700129
Ref: Library<165>-Footnote-2095700195
Ref: Library<165>-Footnote-2105700261
Ref: Library<165>-Footnote-2115700328
Ref: Library<165>-Footnote-2125700395
Ref: Library<165>-Footnote-2135700462
Ref: Library<165>-Footnote-2145700529
Ref: Library<165>-Footnote-2155700596
Ref: Library<165>-Footnote-2165700663
Ref: Library<165>-Footnote-2175700730
Ref: Library<165>-Footnote-2185700797
Ref: Library<165>-Footnote-2195700864
Ref: Library<165>-Footnote-2205700931
Ref: Library<165>-Footnote-2215700998
Ref: Library<165>-Footnote-2225701065
Ref: Library<165>-Footnote-2235701132
Ref: Library<165>-Footnote-2245701199
Node: IDLE<60>5701266
Ref: whatsnew/changelog id9115701378
Ref: 1ceb5701378
Ref: IDLE<60>-Footnote-15706957
Ref: IDLE<60>-Footnote-25707022
Ref: IDLE<60>-Footnote-35707087
Ref: IDLE<60>-Footnote-45707152
Ref: IDLE<60>-Footnote-55707217
Ref: IDLE<60>-Footnote-65707282
Ref: IDLE<60>-Footnote-75707347
Ref: IDLE<60>-Footnote-85707412
Ref: IDLE<60>-Footnote-95707477
Ref: IDLE<60>-Footnote-105707542
Ref: IDLE<60>-Footnote-115707608
Ref: IDLE<60>-Footnote-125707674
Ref: IDLE<60>-Footnote-135707740
Ref: IDLE<60>-Footnote-145707806
Ref: IDLE<60>-Footnote-155707872
Ref: IDLE<60>-Footnote-165707938
Ref: IDLE<60>-Footnote-175708004
Ref: IDLE<60>-Footnote-185708070
Ref: IDLE<60>-Footnote-195708136
Ref: IDLE<60>-Footnote-205708202
Ref: IDLE<60>-Footnote-215708268
Ref: IDLE<60>-Footnote-225708334
Ref: IDLE<60>-Footnote-235708400
Ref: IDLE<60>-Footnote-245708466
Ref: IDLE<60>-Footnote-255708532
Ref: IDLE<60>-Footnote-265708598
Ref: IDLE<60>-Footnote-275708664
Ref: IDLE<60>-Footnote-285708730
Node: Documentation<75>5708796
Ref: whatsnew/changelog id9125708905
Ref: 1cec5708905
Ref: Documentation<75>-Footnote-15709701
Ref: Documentation<75>-Footnote-25709766
Ref: Documentation<75>-Footnote-35709830
Ref: Documentation<75>-Footnote-45709895
Ref: Documentation<75>-Footnote-55709960
Node: Tests<79>5710025
Ref: whatsnew/changelog id9135710135
Ref: 1ced5710135
Ref: Tests<79>-Footnote-15711891
Ref: Tests<79>-Footnote-25711956
Ref: Tests<79>-Footnote-35712021
Ref: Tests<79>-Footnote-45712086
Ref: Tests<79>-Footnote-55712151
Ref: Tests<79>-Footnote-65712216
Ref: Tests<79>-Footnote-75712281
Ref: Tests<79>-Footnote-85712346
Ref: Tests<79>-Footnote-95712411
Ref: Tests<79>-Footnote-105712476
Ref: Tests<79>-Footnote-115712542
Ref: Tests<79>-Footnote-125712608
Ref: Tests<79>-Footnote-135712674
Node: Build<87>5712740
Ref: whatsnew/changelog id9145712844
Ref: 1cee5712844
Ref: Build<87>-Footnote-15715574
Ref: Build<87>-Footnote-25715639
Ref: Build<87>-Footnote-35715704
Ref: Build<87>-Footnote-45715769
Ref: Build<87>-Footnote-55715834
Ref: Build<87>-Footnote-65715899
Ref: Build<87>-Footnote-75715964
Ref: Build<87>-Footnote-85716029
Ref: Build<87>-Footnote-95716094
Ref: Build<87>-Footnote-105716159
Ref: Build<87>-Footnote-115716225
Ref: Build<87>-Footnote-125716291
Ref: Build<87>-Footnote-135716357
Ref: Build<87>-Footnote-145716423
Ref: Build<87>-Footnote-155716489
Ref: Build<87>-Footnote-165716555
Ref: Build<87>-Footnote-175716621
Ref: Build<87>-Footnote-185716687
Ref: Build<87>-Footnote-195716753
Node: Windows<74>5716819
Ref: whatsnew/changelog id9155716929
Ref: 1cef5716929
Ref: Windows<74>-Footnote-15717577
Ref: Windows<74>-Footnote-25717642
Ref: Windows<74>-Footnote-35717707
Ref: Windows<74>-Footnote-45717772
Ref: Windows<74>-Footnote-55717837
Ref: Windows<74>-Footnote-65717902
Node: Tools/Demos<47>5717967
Ref: whatsnew/changelog id9165718077
Ref: 1cf05718077
Ref: Tools/Demos<47>-Footnote-15718867
Ref: Tools/Demos<47>-Footnote-25718932
Ref: Tools/Demos<47>-Footnote-35718997
Ref: Tools/Demos<47>-Footnote-45719062
Ref: Tools/Demos<47>-Footnote-55719127
Ref: Tools/Demos<47>-Footnote-65719192
Node: C API<73>5719257
Ref: whatsnew/changelog id9175719347
Ref: 1cf15719347
Ref: C API<73>-Footnote-15719844
Ref: C API<73>-Footnote-25719909
Node: Python 3 5 5 final5719974
Ref: whatsnew/changelog python-3-5-5-final5720108
Ref: 1cf25720108
Node: Python 3 5 5 release candidate 15720236
Ref: whatsnew/changelog python-3-5-5-release-candidate-15720368
Ref: 1cf35720368
Node: Security<54>5720587
Ref: whatsnew/changelog id9185720699
Ref: 1cf45720699
Ref: Security<54>-Footnote-15721972
Ref: Security<54>-Footnote-25722037
Ref: Security<54>-Footnote-35722102
Ref: Security<54>-Footnote-45722167
Ref: Security<54>-Footnote-55722232
Ref: Security<54>-Footnote-65722290
Node: Core and Builtins<164>5722355
Ref: whatsnew/changelog id9195722488
Ref: 1cf55722488
Ref: Core and Builtins<164>-Footnote-15722715
Node: Library<166>5722780
Ref: whatsnew/changelog id9205722892
Ref: 1cf65722892
Ref: Library<166>-Footnote-15723421
Ref: Library<166>-Footnote-25723486
Node: Python 3 5 4 final5723551
Ref: whatsnew/changelog python-3-5-4-final5723697
Ref: 1cf75723697
Node: Library<167>5723817
Ref: whatsnew/changelog id9215723884
Ref: 1cf85723884
Ref: Library<167>-Footnote-15724084
Node: Python 3 5 4 release candidate 15724149
Ref: whatsnew/changelog python-3-5-4-release-candidate-15724281
Ref: 1cf95724281
Node: Security<55>5724620
Ref: whatsnew/changelog id9225724732
Ref: 1cfa5724732
Ref: Security<55>-Footnote-15726060
Ref: Security<55>-Footnote-25726125
Ref: Security<55>-Footnote-35726190
Ref: Security<55>-Footnote-45726245
Ref: Security<55>-Footnote-55726300
Ref: Security<55>-Footnote-65726355
Ref: Security<55>-Footnote-75726410
Ref: Security<55>-Footnote-85726465
Ref: Security<55>-Footnote-95726520
Ref: Security<55>-Footnote-105726585
Ref: Security<55>-Footnote-115726651
Ref: Security<55>-Footnote-125726707
Node: Core and Builtins<165>5726763
Ref: whatsnew/changelog id9235726896
Ref: 1cfb5726896
Ref: Core and Builtins<165>-Footnote-15729153
Ref: Core and Builtins<165>-Footnote-25729218
Ref: Core and Builtins<165>-Footnote-35729283
Ref: Core and Builtins<165>-Footnote-45729348
Ref: Core and Builtins<165>-Footnote-55729413
Ref: Core and Builtins<165>-Footnote-65729478
Ref: Core and Builtins<165>-Footnote-75729543
Ref: Core and Builtins<165>-Footnote-85729608
Ref: Core and Builtins<165>-Footnote-95729673
Ref: Core and Builtins<165>-Footnote-105729738
Ref: Core and Builtins<165>-Footnote-115729804
Ref: Core and Builtins<165>-Footnote-125729870
Ref: Core and Builtins<165>-Footnote-135729936
Ref: Core and Builtins<165>-Footnote-145730002
Ref: Core and Builtins<165>-Footnote-155730068
Node: Library<168>5730134
Ref: whatsnew/changelog id9245730272
Ref: 1cfc5730272
Ref: Library<168>-Footnote-15740475
Ref: Library<168>-Footnote-25740540
Ref: Library<168>-Footnote-35740605
Ref: Library<168>-Footnote-45740670
Ref: Library<168>-Footnote-55740735
Ref: Library<168>-Footnote-65740800
Ref: Library<168>-Footnote-75740865
Ref: Library<168>-Footnote-85740930
Ref: Library<168>-Footnote-95740995
Ref: Library<168>-Footnote-105741060
Ref: Library<168>-Footnote-115741126
Ref: Library<168>-Footnote-125741192
Ref: Library<168>-Footnote-135741258
Ref: Library<168>-Footnote-145741324
Ref: Library<168>-Footnote-155741390
Ref: Library<168>-Footnote-165741456
Ref: Library<168>-Footnote-175741522
Ref: Library<168>-Footnote-185741588
Ref: Library<168>-Footnote-195741654
Ref: Library<168>-Footnote-205741720
Ref: Library<168>-Footnote-215741786
Ref: Library<168>-Footnote-225741852
Ref: Library<168>-Footnote-235741918
Ref: Library<168>-Footnote-245741984
Ref: Library<168>-Footnote-255742050
Ref: Library<168>-Footnote-265742116
Ref: Library<168>-Footnote-275742182
Ref: Library<168>-Footnote-285742248
Ref: Library<168>-Footnote-295742314
Ref: Library<168>-Footnote-305742380
Ref: Library<168>-Footnote-315742446
Ref: Library<168>-Footnote-325742512
Ref: Library<168>-Footnote-335742578
Ref: Library<168>-Footnote-345742644
Ref: Library<168>-Footnote-355742710
Ref: Library<168>-Footnote-365742776
Ref: Library<168>-Footnote-375742842
Ref: Library<168>-Footnote-385742908
Ref: Library<168>-Footnote-395742974
Ref: Library<168>-Footnote-405743040
Ref: Library<168>-Footnote-415743106
Ref: Library<168>-Footnote-425743172
Ref: Library<168>-Footnote-435743238
Ref: Library<168>-Footnote-445743304
Ref: Library<168>-Footnote-455743370
Ref: Library<168>-Footnote-465743436
Ref: Library<168>-Footnote-475743502
Ref: Library<168>-Footnote-485743568
Ref: Library<168>-Footnote-495743634
Ref: Library<168>-Footnote-505743700
Ref: Library<168>-Footnote-515743766
Ref: Library<168>-Footnote-525743832
Ref: Library<168>-Footnote-535743898
Ref: Library<168>-Footnote-545743964
Ref: Library<168>-Footnote-555744029
Ref: Library<168>-Footnote-565744095
Ref: Library<168>-Footnote-575744161
Ref: Library<168>-Footnote-585744227
Ref: Library<168>-Footnote-595744293
Ref: Library<168>-Footnote-605744359
Ref: Library<168>-Footnote-615744425
Ref: Library<168>-Footnote-625744491
Ref: Library<168>-Footnote-635744557
Ref: Library<168>-Footnote-645744623
Ref: Library<168>-Footnote-655744689
Ref: Library<168>-Footnote-665744755
Ref: Library<168>-Footnote-675744821
Ref: Library<168>-Footnote-685744887
Ref: Library<168>-Footnote-695744953
Ref: Library<168>-Footnote-705745019
Ref: Library<168>-Footnote-715745085
Ref: Library<168>-Footnote-725745151
Ref: Library<168>-Footnote-735745217
Ref: Library<168>-Footnote-745745283
Node: Documentation<76>5745349
Ref: whatsnew/changelog id9255745474
Ref: 1cfd5745474
Ref: Documentation<76>-Footnote-15746186
Ref: Documentation<76>-Footnote-25746251
Ref: Documentation<76>-Footnote-35746316
Ref: Documentation<76>-Footnote-45746381
Ref: Documentation<76>-Footnote-55746446
Ref: Documentation<76>-Footnote-65746511
Node: Tests<80>5746576
Ref: whatsnew/changelog id9265746698
Ref: 1cfe5746698
Ref: Tests<80>-Footnote-15748807
Ref: Tests<80>-Footnote-25748872
Ref: Tests<80>-Footnote-35748937
Ref: Tests<80>-Footnote-45749002
Ref: Tests<80>-Footnote-55749067
Ref: Tests<80>-Footnote-65749132
Ref: Tests<80>-Footnote-75749197
Ref: Tests<80>-Footnote-85749262
Ref: Tests<80>-Footnote-95749327
Node: Build<88>5749392
Ref: whatsnew/changelog id9275749508
Ref: 1cff5749508
Ref: Build<88>-Footnote-15750026
Ref: Build<88>-Footnote-25750091
Ref: Build<88>-Footnote-35750156
Node: Windows<75>5750221
Ref: whatsnew/changelog id9285750337
Ref: 1d005750337
Ref: Windows<75>-Footnote-15750597
Ref: Windows<75>-Footnote-25750662
Node: C API<74>5750727
Ref: whatsnew/changelog id9295750825
Ref: 1d015750825
Ref: C API<74>-Footnote-15751434
Ref: C API<74>-Footnote-25751499
Node: Python 3 5 3 final5751564
Ref: whatsnew/changelog python-3-5-3-final5751710
Ref: 1d025751710
Node: Python 3 5 3 release candidate 15751857
Ref: whatsnew/changelog python-3-5-3-release-candidate-15751989
Ref: 1d035751989
Node: Security<56>5752378
Ref: whatsnew/changelog id9305752490
Ref: 1d045752490
Ref: Security<56>-Footnote-15752870
Ref: Security<56>-Footnote-25752935
Node: Core and Builtins<166>5753000
Ref: whatsnew/changelog id9315753133
Ref: 1d055753133
Ref: Core and Builtins<166>-Footnote-15758593
Ref: Core and Builtins<166>-Footnote-25758658
Ref: Core and Builtins<166>-Footnote-35758723
Ref: Core and Builtins<166>-Footnote-45758788
Ref: Core and Builtins<166>-Footnote-55758853
Ref: Core and Builtins<166>-Footnote-65758918
Ref: Core and Builtins<166>-Footnote-75758983
Ref: Core and Builtins<166>-Footnote-85759048
Ref: Core and Builtins<166>-Footnote-95759113
Ref: Core and Builtins<166>-Footnote-105759178
Ref: Core and Builtins<166>-Footnote-115759244
Ref: Core and Builtins<166>-Footnote-125759310
Ref: Core and Builtins<166>-Footnote-135759376
Ref: Core and Builtins<166>-Footnote-145759442
Ref: Core and Builtins<166>-Footnote-155759508
Ref: Core and Builtins<166>-Footnote-165759574
Ref: Core and Builtins<166>-Footnote-175759640
Ref: Core and Builtins<166>-Footnote-185759706
Ref: Core and Builtins<166>-Footnote-195759772
Ref: Core and Builtins<166>-Footnote-205759838
Ref: Core and Builtins<166>-Footnote-215759904
Ref: Core and Builtins<166>-Footnote-225759970
Ref: Core and Builtins<166>-Footnote-235760036
Ref: Core and Builtins<166>-Footnote-245760102
Ref: Core and Builtins<166>-Footnote-255760168
Ref: Core and Builtins<166>-Footnote-265760234
Ref: Core and Builtins<166>-Footnote-275760300
Ref: Core and Builtins<166>-Footnote-285760366
Ref: Core and Builtins<166>-Footnote-295760432
Ref: Core and Builtins<166>-Footnote-305760498
Ref: Core and Builtins<166>-Footnote-315760564
Ref: Core and Builtins<166>-Footnote-325760630
Ref: Core and Builtins<166>-Footnote-335760696
Ref: Core and Builtins<166>-Footnote-345760762
Ref: Core and Builtins<166>-Footnote-355760828
Ref: Core and Builtins<166>-Footnote-365760894
Ref: Core and Builtins<166>-Footnote-375760960
Ref: Core and Builtins<166>-Footnote-385761026
Ref: Core and Builtins<166>-Footnote-395761092
Ref: Core and Builtins<166>-Footnote-405761158
Ref: Core and Builtins<166>-Footnote-415761224
Ref: Core and Builtins<166>-Footnote-425761290
Ref: Core and Builtins<166>-Footnote-435761356
Node: Library<169>5761422
Ref: whatsnew/changelog id9325761551
Ref: 1d065761551
Ref: Library<169>-Footnote-15777566
Ref: Library<169>-Footnote-25777631
Ref: Library<169>-Footnote-35777696
Ref: Library<169>-Footnote-45777761
Ref: Library<169>-Footnote-55777826
Ref: Library<169>-Footnote-65777890
Ref: Library<169>-Footnote-75777955
Ref: Library<169>-Footnote-85778020
Ref: Library<169>-Footnote-95778085
Ref: Library<169>-Footnote-105778150
Ref: Library<169>-Footnote-115778216
Ref: Library<169>-Footnote-125778282
Ref: Library<169>-Footnote-135778348
Ref: Library<169>-Footnote-145778414
Ref: Library<169>-Footnote-155778480
Ref: Library<169>-Footnote-165778546
Ref: Library<169>-Footnote-175778612
Ref: Library<169>-Footnote-185778678
Ref: Library<169>-Footnote-195778744
Ref: Library<169>-Footnote-205778810
Ref: Library<169>-Footnote-215778876
Ref: Library<169>-Footnote-225778942
Ref: Library<169>-Footnote-235779008
Ref: Library<169>-Footnote-245779074
Ref: Library<169>-Footnote-255779140
Ref: Library<169>-Footnote-265779206
Ref: Library<169>-Footnote-275779272
Ref: Library<169>-Footnote-285779338
Ref: Library<169>-Footnote-295779404
Ref: Library<169>-Footnote-305779470
Ref: Library<169>-Footnote-315779536
Ref: Library<169>-Footnote-325779602
Ref: Library<169>-Footnote-335779670
Ref: Library<169>-Footnote-345779736
Ref: Library<169>-Footnote-355779802
Ref: Library<169>-Footnote-365779868
Ref: Library<169>-Footnote-375779934
Ref: Library<169>-Footnote-385780000
Ref: Library<169>-Footnote-395780066
Ref: Library<169>-Footnote-405780132
Ref: Library<169>-Footnote-415780198
Ref: Library<169>-Footnote-425780264
Ref: Library<169>-Footnote-435780330
Ref: Library<169>-Footnote-445780396
Ref: Library<169>-Footnote-455780462
Ref: Library<169>-Footnote-465780528
Ref: Library<169>-Footnote-475780594
Ref: Library<169>-Footnote-485780660
Ref: Library<169>-Footnote-495780726
Ref: Library<169>-Footnote-505780792
Ref: Library<169>-Footnote-515780858
Ref: Library<169>-Footnote-525780924
Ref: Library<169>-Footnote-535780990
Ref: Library<169>-Footnote-545781056
Ref: Library<169>-Footnote-555781122
Ref: Library<169>-Footnote-565781188
Ref: Library<169>-Footnote-575781254
Ref: Library<169>-Footnote-585781320
Ref: Library<169>-Footnote-595781386
Ref: Library<169>-Footnote-605781452
Ref: Library<169>-Footnote-615781508
Ref: Library<169>-Footnote-625781574
Ref: Library<169>-Footnote-635781640
Ref: Library<169>-Footnote-645781706
Ref: Library<169>-Footnote-655781772
Ref: Library<169>-Footnote-665781838
Ref: Library<169>-Footnote-675781904
Ref: Library<169>-Footnote-685781970
Ref: Library<169>-Footnote-695782036
Ref: Library<169>-Footnote-705782102
Ref: Library<169>-Footnote-715782168
Ref: Library<169>-Footnote-725782234
Ref: Library<169>-Footnote-735782299
Ref: Library<169>-Footnote-745782365
Ref: Library<169>-Footnote-755782431
Ref: Library<169>-Footnote-765782497
Ref: Library<169>-Footnote-775782563
Ref: Library<169>-Footnote-785782629
Ref: Library<169>-Footnote-795782695
Ref: Library<169>-Footnote-805782761
Ref: Library<169>-Footnote-815782820
Ref: Library<169>-Footnote-825782886
Ref: Library<169>-Footnote-835782952
Ref: Library<169>-Footnote-845783018
Ref: Library<169>-Footnote-855783084
Ref: Library<169>-Footnote-865783150
Ref: Library<169>-Footnote-875783216
Ref: Library<169>-Footnote-885783282
Ref: Library<169>-Footnote-895783348
Ref: Library<169>-Footnote-905783414
Ref: Library<169>-Footnote-915783480
Ref: Library<169>-Footnote-925783546
Ref: Library<169>-Footnote-935783612
Ref: Library<169>-Footnote-945783678
Ref: Library<169>-Footnote-955783744
Ref: Library<169>-Footnote-965783810
Ref: Library<169>-Footnote-975783876
Ref: Library<169>-Footnote-985783919
Ref: Library<169>-Footnote-995783985
Ref: Library<169>-Footnote-1005784051
Ref: Library<169>-Footnote-1015784118
Ref: Library<169>-Footnote-1025784185
Ref: Library<169>-Footnote-1035784252
Ref: Library<169>-Footnote-1045784319
Ref: Library<169>-Footnote-1055784386
Ref: Library<169>-Footnote-1065784453
Ref: Library<169>-Footnote-1075784520
Ref: Library<169>-Footnote-1085784587
Ref: Library<169>-Footnote-1095784654
Ref: Library<169>-Footnote-1105784721
Ref: Library<169>-Footnote-1115784788
Ref: Library<169>-Footnote-1125784855
Ref: Library<169>-Footnote-1135784922
Ref: Library<169>-Footnote-1145784989
Ref: Library<169>-Footnote-1155785056
Ref: Library<169>-Footnote-1165785123
Ref: Library<169>-Footnote-1175785190
Ref: Library<169>-Footnote-1185785257
Ref: Library<169>-Footnote-1195785324
Ref: Library<169>-Footnote-1205785391
Ref: Library<169>-Footnote-1215785458
Ref: Library<169>-Footnote-1225785525
Ref: Library<169>-Footnote-1235785592
Ref: Library<169>-Footnote-1245785659
Ref: Library<169>-Footnote-1255785726
Ref: Library<169>-Footnote-1265785793
Node: IDLE<61>5785860
Ref: whatsnew/changelog id9335785976
Ref: 1d075785976
Ref: IDLE<61>-Footnote-15787227
Ref: IDLE<61>-Footnote-25787292
Ref: IDLE<61>-Footnote-35787357
Ref: IDLE<61>-Footnote-45787422
Ref: IDLE<61>-Footnote-55787487
Ref: IDLE<61>-Footnote-65787552
Ref: IDLE<61>-Footnote-75787617
Ref: IDLE<61>-Footnote-85787682
Node: C API<75>5787747
Ref: whatsnew/changelog id9345787868
Ref: 1d085787868
Ref: C API<75>-Footnote-15788200
Ref: C API<75>-Footnote-25788265
Node: Documentation<77>5788330
Ref: whatsnew/changelog id9355788452
Ref: 1d095788452
Ref: Documentation<77>-Footnote-15788605
Node: Tests<81>5788670
Ref: whatsnew/changelog id9365788798
Ref: 1d0a5788798
Ref: Tests<81>-Footnote-15789491
Ref: Tests<81>-Footnote-25789556
Ref: Tests<81>-Footnote-35789621
Ref: Tests<81>-Footnote-45789686
Ref: Tests<81>-Footnote-55789751
Ref: Tests<81>-Footnote-65789816
Node: Tools/Demos<48>5789881
Ref: whatsnew/changelog id9375790003
Ref: 1d0b5790003
Ref: Tools/Demos<48>-Footnote-15790487
Ref: Tools/Demos<48>-Footnote-25790552
Ref: Tools/Demos<48>-Footnote-35790617
Node: Windows<76>5790682
Ref: whatsnew/changelog id9385790804
Ref: 1d0c5790804
Ref: Windows<76>-Footnote-15791306
Ref: Windows<76>-Footnote-25791371
Ref: Windows<76>-Footnote-35791436
Ref: Windows<76>-Footnote-45791501
Ref: Windows<76>-Footnote-55791566
Node: Build<89>5791631
Ref: whatsnew/changelog id9395791729
Ref: 1d0d5791729
Ref: Build<89>-Footnote-15794438
Ref: Build<89>-Footnote-25794503
Ref: Build<89>-Footnote-35794568
Ref: Build<89>-Footnote-45794633
Ref: Build<89>-Footnote-55794698
Ref: Build<89>-Footnote-65794763
Ref: Build<89>-Footnote-75794828
Ref: Build<89>-Footnote-85794893
Ref: Build<89>-Footnote-95794958
Ref: Build<89>-Footnote-105795023
Ref: Build<89>-Footnote-115795089
Ref: Build<89>-Footnote-125795155
Ref: Build<89>-Footnote-135795221
Ref: Build<89>-Footnote-145795287
Ref: Build<89>-Footnote-155795353
Ref: Build<89>-Footnote-165795419
Ref: Build<89>-Footnote-175795485
Ref: Build<89>-Footnote-185795551
Ref: Build<89>-Footnote-195795617
Ref: Build<89>-Footnote-205795683
Ref: Build<89>-Footnote-215795749
Ref: Build<89>-Footnote-225795815
Node: Python 3 5 2 final5795881
Ref: whatsnew/changelog python-3-5-2-final5796027
Ref: 1d0e5796027
Node: Core and Builtins<167>5796205
Ref: whatsnew/changelog id9405796300
Ref: 1d0f5796300
Ref: Core and Builtins<167>-Footnote-15796460
Node: Tests<82>5796525
Ref: whatsnew/changelog id9415796637
Ref: 1d105796637
Ref: Tests<82>-Footnote-15796799
Node: IDLE<62>5796864
Ref: whatsnew/changelog id9425796945
Ref: 1d115796945
Ref: IDLE<62>-Footnote-15797101
Node: Python 3 5 2 release candidate 15797166
Ref: whatsnew/changelog python-3-5-2-release-candidate-15797298
Ref: 1d125797298
Node: Security<57>5797667
Ref: whatsnew/changelog id9435797779
Ref: 1d135797779
Ref: Security<57>-Footnote-15798688
Ref: Security<57>-Footnote-25798753
Ref: Security<57>-Footnote-35798808
Ref: Security<57>-Footnote-45798863
Ref: Security<57>-Footnote-55798928
Ref: Security<57>-Footnote-65798993
Ref: Security<57>-Footnote-75799058
Node: Core and Builtins<168>5799123
Ref: whatsnew/changelog id9445799256
Ref: 1d145799256
Ref: Core and Builtins<168>-Footnote-15805109
Ref: Core and Builtins<168>-Footnote-25805174
Ref: Core and Builtins<168>-Footnote-35805239
Ref: Core and Builtins<168>-Footnote-45805304
Ref: Core and Builtins<168>-Footnote-55805369
Ref: Core and Builtins<168>-Footnote-65805434
Ref: Core and Builtins<168>-Footnote-75805499
Ref: Core and Builtins<168>-Footnote-85805564
Ref: Core and Builtins<168>-Footnote-95805629
Ref: Core and Builtins<168>-Footnote-105805694
Ref: Core and Builtins<168>-Footnote-115805760
Ref: Core and Builtins<168>-Footnote-125805826
Ref: Core and Builtins<168>-Footnote-135805892
Ref: Core and Builtins<168>-Footnote-145805958
Ref: Core and Builtins<168>-Footnote-155806024
Ref: Core and Builtins<168>-Footnote-165806090
Ref: Core and Builtins<168>-Footnote-175806156
Ref: Core and Builtins<168>-Footnote-185806221
Ref: Core and Builtins<168>-Footnote-195806287
Ref: Core and Builtins<168>-Footnote-205806353
Ref: Core and Builtins<168>-Footnote-215806419
Ref: Core and Builtins<168>-Footnote-225806485
Ref: Core and Builtins<168>-Footnote-235806551
Ref: Core and Builtins<168>-Footnote-245806617
Ref: Core and Builtins<168>-Footnote-255806683
Ref: Core and Builtins<168>-Footnote-265806749
Ref: Core and Builtins<168>-Footnote-275806815
Ref: Core and Builtins<168>-Footnote-285806881
Ref: Core and Builtins<168>-Footnote-295806947
Ref: Core and Builtins<168>-Footnote-305807013
Ref: Core and Builtins<168>-Footnote-315807079
Ref: Core and Builtins<168>-Footnote-325807122
Ref: Core and Builtins<168>-Footnote-335807188
Ref: Core and Builtins<168>-Footnote-345807254
Ref: Core and Builtins<168>-Footnote-355807320
Ref: Core and Builtins<168>-Footnote-365807386
Ref: Core and Builtins<168>-Footnote-375807452
Ref: Core and Builtins<168>-Footnote-385807518
Node: Library<170>5807584
Ref: whatsnew/changelog id9455807713
Ref: 1d155807713
Ref: Library<170>-Footnote-15824534
Ref: Library<170>-Footnote-25824599
Ref: Library<170>-Footnote-35824664
Ref: Library<170>-Footnote-45824706
Ref: Library<170>-Footnote-55824771
Ref: Library<170>-Footnote-65824836
Ref: Library<170>-Footnote-75824901
Ref: Library<170>-Footnote-85824966
Ref: Library<170>-Footnote-95825031
Ref: Library<170>-Footnote-105825096
Ref: Library<170>-Footnote-115825162
Ref: Library<170>-Footnote-125825228
Ref: Library<170>-Footnote-135825294
Ref: Library<170>-Footnote-145825360
Ref: Library<170>-Footnote-155825426
Ref: Library<170>-Footnote-165825492
Ref: Library<170>-Footnote-175825558
Ref: Library<170>-Footnote-185825624
Ref: Library<170>-Footnote-195825690
Ref: Library<170>-Footnote-205825756
Ref: Library<170>-Footnote-215825822
Ref: Library<170>-Footnote-225825888
Ref: Library<170>-Footnote-235825954
Ref: Library<170>-Footnote-245826020
Ref: Library<170>-Footnote-255826086
Ref: Library<170>-Footnote-265826152
Ref: Library<170>-Footnote-275826218
Ref: Library<170>-Footnote-285826284
Ref: Library<170>-Footnote-295826350
Ref: Library<170>-Footnote-305826416
Ref: Library<170>-Footnote-315826482
Ref: Library<170>-Footnote-325826548
Ref: Library<170>-Footnote-335826614
Ref: Library<170>-Footnote-345826680
Ref: Library<170>-Footnote-355826746
Ref: Library<170>-Footnote-365826812
Ref: Library<170>-Footnote-375826878
Ref: Library<170>-Footnote-385826944
Ref: Library<170>-Footnote-395827010
Ref: Library<170>-Footnote-405827076
Ref: Library<170>-Footnote-415827142
Ref: Library<170>-Footnote-425827208
Ref: Library<170>-Footnote-435827274
Ref: Library<170>-Footnote-445827340
Ref: Library<170>-Footnote-455827406
Ref: Library<170>-Footnote-465827472
Ref: Library<170>-Footnote-475827538
Ref: Library<170>-Footnote-485827604
Ref: Library<170>-Footnote-495827670
Ref: Library<170>-Footnote-505827736
Ref: Library<170>-Footnote-515827802
Ref: Library<170>-Footnote-525827868
Ref: Library<170>-Footnote-535827934
Ref: Library<170>-Footnote-545828000
Ref: Library<170>-Footnote-555828066
Ref: Library<170>-Footnote-565828132
Ref: Library<170>-Footnote-575828198
Ref: Library<170>-Footnote-585828264
Ref: Library<170>-Footnote-595828330
Ref: Library<170>-Footnote-605828396
Ref: Library<170>-Footnote-615828462
Ref: Library<170>-Footnote-625828527
Ref: Library<170>-Footnote-635828593
Ref: Library<170>-Footnote-645828659
Ref: Library<170>-Footnote-655828725
Ref: Library<170>-Footnote-665828791
Ref: Library<170>-Footnote-675828857
Ref: Library<170>-Footnote-685828923
Ref: Library<170>-Footnote-695828989
Ref: Library<170>-Footnote-705829055
Ref: Library<170>-Footnote-715829121
Ref: Library<170>-Footnote-725829187
Ref: Library<170>-Footnote-735829253
Ref: Library<170>-Footnote-745829319
Ref: Library<170>-Footnote-755829385
Ref: Library<170>-Footnote-765829451
Ref: Library<170>-Footnote-775829517
Ref: Library<170>-Footnote-785829583
Ref: Library<170>-Footnote-795829649
Ref: Library<170>-Footnote-805829715
Ref: Library<170>-Footnote-815829781
Ref: Library<170>-Footnote-825829847
Ref: Library<170>-Footnote-835829913
Ref: Library<170>-Footnote-845829979
Ref: Library<170>-Footnote-855830045
Ref: Library<170>-Footnote-865830111
Ref: Library<170>-Footnote-875830177
Ref: Library<170>-Footnote-885830243
Ref: Library<170>-Footnote-895830309
Ref: Library<170>-Footnote-905830375
Ref: Library<170>-Footnote-915830441
Ref: Library<170>-Footnote-925830507
Ref: Library<170>-Footnote-935830573
Ref: Library<170>-Footnote-945830639
Ref: Library<170>-Footnote-955830705
Ref: Library<170>-Footnote-965830771
Ref: Library<170>-Footnote-975830837
Ref: Library<170>-Footnote-985830903
Ref: Library<170>-Footnote-995830969
Ref: Library<170>-Footnote-1005831035
Ref: Library<170>-Footnote-1015831102
Ref: Library<170>-Footnote-1025831168
Ref: Library<170>-Footnote-1035831235
Ref: Library<170>-Footnote-1045831302
Ref: Library<170>-Footnote-1055831369
Ref: Library<170>-Footnote-1065831436
Ref: Library<170>-Footnote-1075831503
Ref: Library<170>-Footnote-1085831570
Ref: Library<170>-Footnote-1095831637
Ref: Library<170>-Footnote-1105831704
Ref: Library<170>-Footnote-1115831771
Ref: Library<170>-Footnote-1125831838
Ref: Library<170>-Footnote-1135831905
Ref: Library<170>-Footnote-1145831972
Ref: Library<170>-Footnote-1155832039
Ref: Library<170>-Footnote-1165832106
Ref: Library<170>-Footnote-1175832173
Ref: Library<170>-Footnote-1185832240
Ref: Library<170>-Footnote-1195832307
Ref: Library<170>-Footnote-1205832374
Node: IDLE<63>5832441
Ref: whatsnew/changelog id9465832565
Ref: 1d165832565
Ref: IDLE<63>-Footnote-15834928
Ref: IDLE<63>-Footnote-25834992
Ref: IDLE<63>-Footnote-35835057
Ref: IDLE<63>-Footnote-45835122
Ref: IDLE<63>-Footnote-55835187
Ref: IDLE<63>-Footnote-65835252
Ref: IDLE<63>-Footnote-75835317
Ref: IDLE<63>-Footnote-85835382
Ref: IDLE<63>-Footnote-95835447
Ref: IDLE<63>-Footnote-105835512
Ref: IDLE<63>-Footnote-115835578
Ref: IDLE<63>-Footnote-125835644
Ref: IDLE<63>-Footnote-135835710
Ref: IDLE<63>-Footnote-145835776
Ref: IDLE<63>-Footnote-155835842
Node: Documentation<78>5835908
Ref: whatsnew/changelog id9475836029
Ref: 1d175836029
Ref: Documentation<78>-Footnote-15836989
Ref: Documentation<78>-Footnote-25837054
Ref: Documentation<78>-Footnote-35837119
Ref: Documentation<78>-Footnote-45837161
Ref: Documentation<78>-Footnote-55837226
Ref: Documentation<78>-Footnote-65837290
Ref: Documentation<78>-Footnote-75837355
Ref: Documentation<78>-Footnote-85837420
Node: Tests<83>5837485
Ref: whatsnew/changelog id9485837607
Ref: 1d185837607
Ref: Tests<83>-Footnote-15838482
Ref: Tests<83>-Footnote-25838547
Ref: Tests<83>-Footnote-35838612
Ref: Tests<83>-Footnote-45838677
Ref: Tests<83>-Footnote-55838742
Ref: Tests<83>-Footnote-65838807
Ref: Tests<83>-Footnote-75838872
Node: Build<90>5838937
Ref: whatsnew/changelog id9495839053
Ref: 1d195839053
Ref: Build<90>-Footnote-15841581
Ref: Build<90>-Footnote-25841646
Ref: Build<90>-Footnote-35841711
Ref: Build<90>-Footnote-45841776
Ref: Build<90>-Footnote-55841841
Ref: Build<90>-Footnote-65841906
Ref: Build<90>-Footnote-75841971
Ref: Build<90>-Footnote-85842036
Ref: Build<90>-Footnote-95842101
Ref: Build<90>-Footnote-105842166
Ref: Build<90>-Footnote-115842232
Ref: Build<90>-Footnote-125842298
Ref: Build<90>-Footnote-135842364
Ref: Build<90>-Footnote-145842430
Ref: Build<90>-Footnote-155842496
Ref: Build<90>-Footnote-165842562
Ref: Build<90>-Footnote-175842628
Node: Windows<77>5842694
Ref: whatsnew/changelog id9505842816
Ref: 1d1a5842816
Ref: Windows<77>-Footnote-15843526
Ref: Windows<77>-Footnote-25843591
Ref: Windows<77>-Footnote-35843656
Ref: Windows<77>-Footnote-45843721
Ref: Windows<77>-Footnote-55843786
Ref: Windows<77>-Footnote-65843851
Node: Tools/Demos<49>5843916
Ref: whatsnew/changelog id9515844020
Ref: 1d1b5844020
Ref: Tools/Demos<49>-Footnote-15844644
Ref: Tools/Demos<49>-Footnote-25844709
Ref: Tools/Demos<49>-Footnote-35844774
Ref: Tools/Demos<49>-Footnote-45844839
Node: Python 3 5 1 final5844904
Ref: whatsnew/changelog python-3-5-1-final5845050
Ref: 1d1c5845050
Node: Core and Builtins<169>5845214
Ref: whatsnew/changelog id9525845311
Ref: 1d1d5845311
Ref: Core and Builtins<169>-Footnote-15845497
Node: Windows<78>5845562
Ref: whatsnew/changelog id9535845659
Ref: 1d1e5845659
Ref: Windows<78>-Footnote-15845851
Node: Python 3 5 1 release candidate 15845916
Ref: whatsnew/changelog python-3-5-1-release-candidate-15846048
Ref: 1d1f5846048
Node: Core and Builtins<170>5846391
Ref: whatsnew/changelog id9545846503
Ref: 1d205846503
Ref: Core and Builtins<170>-Footnote-15849651
Ref: Core and Builtins<170>-Footnote-25849716
Ref: Core and Builtins<170>-Footnote-35849781
Ref: Core and Builtins<170>-Footnote-45849846
Ref: Core and Builtins<170>-Footnote-55849911
Ref: Core and Builtins<170>-Footnote-65849976
Ref: Core and Builtins<170>-Footnote-75850041
Ref: Core and Builtins<170>-Footnote-85850106
Ref: Core and Builtins<170>-Footnote-95850171
Ref: Core and Builtins<170>-Footnote-105850236
Ref: Core and Builtins<170>-Footnote-115850302
Ref: Core and Builtins<170>-Footnote-125850368
Ref: Core and Builtins<170>-Footnote-135850434
Ref: Core and Builtins<170>-Footnote-145850500
Ref: Core and Builtins<170>-Footnote-155850566
Ref: Core and Builtins<170>-Footnote-165850632
Ref: Core and Builtins<170>-Footnote-175850698
Ref: Core and Builtins<170>-Footnote-185850764
Ref: Core and Builtins<170>-Footnote-195850830
Node: Library<171>5850896
Ref: whatsnew/changelog id9555851025
Ref: 1d215851025
Ref: Library<171>-Footnote-15861405
Ref: Library<171>-Footnote-25861470
Ref: Library<171>-Footnote-35861535
Ref: Library<171>-Footnote-45861600
Ref: Library<171>-Footnote-55861664
Ref: Library<171>-Footnote-65861729
Ref: Library<171>-Footnote-75861794
Ref: Library<171>-Footnote-85861859
Ref: Library<171>-Footnote-95861924
Ref: Library<171>-Footnote-105861989
Ref: Library<171>-Footnote-115862055
Ref: Library<171>-Footnote-125862121
Ref: Library<171>-Footnote-135862187
Ref: Library<171>-Footnote-145862253
Ref: Library<171>-Footnote-155862319
Ref: Library<171>-Footnote-165862385
Ref: Library<171>-Footnote-175862451
Ref: Library<171>-Footnote-185862517
Ref: Library<171>-Footnote-195862583
Ref: Library<171>-Footnote-205862649
Ref: Library<171>-Footnote-215862715
Ref: Library<171>-Footnote-225862781
Ref: Library<171>-Footnote-235862847
Ref: Library<171>-Footnote-245862913
Ref: Library<171>-Footnote-255862979
Ref: Library<171>-Footnote-265863045
Ref: Library<171>-Footnote-275863111
Ref: Library<171>-Footnote-285863177
Ref: Library<171>-Footnote-295863243
Ref: Library<171>-Footnote-305863309
Ref: Library<171>-Footnote-315863375
Ref: Library<171>-Footnote-325863441
Ref: Library<171>-Footnote-335863507
Ref: Library<171>-Footnote-345863573
Ref: Library<171>-Footnote-355863639
Ref: Library<171>-Footnote-365863705
Ref: Library<171>-Footnote-375863771
Ref: Library<171>-Footnote-385863837
Ref: Library<171>-Footnote-395863903
Ref: Library<171>-Footnote-405863969
Ref: Library<171>-Footnote-415864035
Ref: Library<171>-Footnote-425864101
Ref: Library<171>-Footnote-435864167
Ref: Library<171>-Footnote-445864233
Ref: Library<171>-Footnote-455864299
Ref: Library<171>-Footnote-465864365
Ref: Library<171>-Footnote-475864431
Ref: Library<171>-Footnote-485864497
Ref: Library<171>-Footnote-495864563
Ref: Library<171>-Footnote-505864629
Ref: Library<171>-Footnote-515864695
Ref: Library<171>-Footnote-525864761
Ref: Library<171>-Footnote-535864827
Ref: Library<171>-Footnote-545864893
Ref: Library<171>-Footnote-555864959
Ref: Library<171>-Footnote-565865025
Ref: Library<171>-Footnote-575865091
Ref: Library<171>-Footnote-585865157
Ref: Library<171>-Footnote-595865223
Ref: Library<171>-Footnote-605865289
Ref: Library<171>-Footnote-615865355
Ref: Library<171>-Footnote-625865421
Ref: Library<171>-Footnote-635865487
Ref: Library<171>-Footnote-645865553
Ref: Library<171>-Footnote-655865619
Ref: Library<171>-Footnote-665865685
Ref: Library<171>-Footnote-675865751
Ref: Library<171>-Footnote-685865817
Ref: Library<171>-Footnote-695865883
Ref: Library<171>-Footnote-705865949
Node: IDLE<64>5866015
Ref: whatsnew/changelog id9565866139
Ref: 1d225866139
Ref: IDLE<64>-Footnote-15871092
Ref: IDLE<64>-Footnote-25871157
Ref: IDLE<64>-Footnote-35871222
Ref: IDLE<64>-Footnote-45871287
Ref: IDLE<64>-Footnote-55871352
Ref: IDLE<64>-Footnote-65871417
Ref: IDLE<64>-Footnote-75871482
Ref: IDLE<64>-Footnote-85871547
Ref: IDLE<64>-Footnote-95871612
Ref: IDLE<64>-Footnote-105871677
Ref: IDLE<64>-Footnote-115871743
Ref: IDLE<64>-Footnote-125871809
Ref: IDLE<64>-Footnote-135871875
Ref: IDLE<64>-Footnote-145871941
Ref: IDLE<64>-Footnote-155872007
Ref: IDLE<64>-Footnote-165872073
Ref: IDLE<64>-Footnote-175872139
Ref: IDLE<64>-Footnote-185872205
Ref: IDLE<64>-Footnote-195872271
Ref: IDLE<64>-Footnote-205872337
Ref: IDLE<64>-Footnote-215872403
Ref: IDLE<64>-Footnote-225872469
Ref: IDLE<64>-Footnote-235872535
Ref: IDLE<64>-Footnote-245872601
Ref: IDLE<64>-Footnote-255872667
Node: Documentation<79>5872733
Ref: whatsnew/changelog id9575872854
Ref: 1d235872854
Ref: Documentation<79>-Footnote-15873937
Ref: Documentation<79>-Footnote-25874002
Ref: Documentation<79>-Footnote-35874067
Ref: Documentation<79>-Footnote-45874132
Ref: Documentation<79>-Footnote-55874197
Ref: Documentation<79>-Footnote-65874262
Node: Tests<84>5874327
Ref: whatsnew/changelog id9585874449
Ref: 1d245874449
Ref: Tests<84>-Footnote-15874958
Ref: Tests<84>-Footnote-25875023
Ref: Tests<84>-Footnote-35875088
Node: Build<91>5875153
Ref: whatsnew/changelog id9595875269
Ref: 1d255875269
Ref: Build<91>-Footnote-15875696
Ref: Build<91>-Footnote-25875761
Ref: Build<91>-Footnote-35875826
Node: Windows<79>5875891
Ref: whatsnew/changelog id9605876013
Ref: 1d265876013
Ref: Windows<79>-Footnote-15877288
Ref: Windows<79>-Footnote-25877353
Ref: Windows<79>-Footnote-35877418
Ref: Windows<79>-Footnote-45877483
Ref: Windows<79>-Footnote-55877548
Ref: Windows<79>-Footnote-65877613
Ref: Windows<79>-Footnote-75877678
Ref: Windows<79>-Footnote-85877743
Ref: Windows<79>-Footnote-95877808
Ref: Windows<79>-Footnote-105877873
Ref: Windows<79>-Footnote-115877939
Ref: Windows<79>-Footnote-125878005
Ref: Windows<79>-Footnote-135878071
Ref: Windows<79>-Footnote-145878137
Node: Tools/Demos<50>5878203
Ref: whatsnew/changelog id9615878307
Ref: 1d275878307
Ref: Tools/Demos<50>-Footnote-15878459
Node: Python 3 5 0 final5878524
Ref: whatsnew/changelog python-3-5-0-final5878670
Ref: 1d285878670
Node: Build<92>5878785
Ref: whatsnew/changelog id9625878849
Ref: 1d295878849
Ref: Build<92>-Footnote-15879027
Node: Python 3 5 0 release candidate 45879092
Ref: whatsnew/changelog python-3-5-0-release-candidate-45879238
Ref: 1d2a5879238
Node: Library<172>5879406
Ref: whatsnew/changelog id9635879505
Ref: 1d2b5879505
Ref: Library<172>-Footnote-15879636
Node: Build<93>5879701
Ref: whatsnew/changelog id9645879800
Ref: 1d2c5879800
Ref: Build<93>-Footnote-15879984
Node: Python 3 5 0 release candidate 35880049
Ref: whatsnew/changelog python-3-5-0-release-candidate-35880209
Ref: 1d2d5880209
Node: Core and Builtins<171>5880402
Ref: whatsnew/changelog id9655880514
Ref: 1d2e5880514
Ref: Core and Builtins<171>-Footnote-15880884
Ref: Core and Builtins<171>-Footnote-25880949
Ref: Core and Builtins<171>-Footnote-35881014
Ref: Core and Builtins<171>-Footnote-45881079
Node: Library<173>5881121
Ref: whatsnew/changelog id9665881233
Ref: 1d2f5881233
Ref: Library<173>-Footnote-15882009
Ref: Library<173>-Footnote-25882074
Ref: Library<173>-Footnote-35882139
Ref: Library<173>-Footnote-45882204
Ref: Library<173>-Footnote-55882269
Node: Python 3 5 0 release candidate 25882334
Ref: whatsnew/changelog python-3-5-0-release-candidate-25882494
Ref: 1d305882494
Node: Core and Builtins<172>5882687
Ref: whatsnew/changelog id9675882799
Ref: 1d315882799
Ref: Core and Builtins<172>-Footnote-15883345
Ref: Core and Builtins<172>-Footnote-25883410
Ref: Core and Builtins<172>-Footnote-35883475
Node: Library<174>5883540
Ref: whatsnew/changelog id9685883652
Ref: 1d325883652
Ref: Library<174>-Footnote-15883935
Ref: Library<174>-Footnote-25884000
Ref: Library<174>-Footnote-35884065
Node: Python 3 5 0 release candidate 15884130
Ref: whatsnew/changelog python-3-5-0-release-candidate-15884277
Ref: 1d335884277
Node: Core and Builtins<173>5884544
Ref: whatsnew/changelog id9695884656
Ref: 1d345884656
Ref: Core and Builtins<173>-Footnote-15884836
Node: Library<175>5884901
Ref: whatsnew/changelog id9705885030
Ref: 1d355885030
Ref: Library<175>-Footnote-15886614
Ref: Library<175>-Footnote-25886679
Ref: Library<175>-Footnote-35886744
Ref: Library<175>-Footnote-45886809
Ref: Library<175>-Footnote-55886873
Ref: Library<175>-Footnote-65886938
Ref: Library<175>-Footnote-75887003
Ref: Library<175>-Footnote-85887068
Ref: Library<175>-Footnote-95887133
Ref: Library<175>-Footnote-105887198
Ref: Library<175>-Footnote-115887264
Ref: Library<175>-Footnote-125887330
Ref: Library<175>-Footnote-135887396
Ref: Library<175>-Footnote-145887462
Ref: Library<175>-Footnote-155887528
Node: IDLE<65>5887594
Ref: whatsnew/changelog id9715887718
Ref: 1d365887718
Ref: IDLE<65>-Footnote-15888471
Ref: IDLE<65>-Footnote-25888536
Ref: IDLE<65>-Footnote-35888601
Ref: IDLE<65>-Footnote-45888666
Node: Documentation<80>5888731
Ref: whatsnew/changelog id9725888852
Ref: 1d375888852
Ref: Documentation<80>-Footnote-15889514
Ref: Documentation<80>-Footnote-25889579
Ref: Documentation<80>-Footnote-35889644
Ref: Documentation<80>-Footnote-45889709
Node: Tests<85>5889774
Ref: whatsnew/changelog id9735889878
Ref: 1d385889878
Ref: Tests<85>-Footnote-15890118
Node: Python 3 5 0 beta 45890183
Ref: whatsnew/changelog python-3-5-0-beta-45890317
Ref: 1d395890317
Node: Core and Builtins<174>5890504
Ref: whatsnew/changelog id9745890603
Ref: 1d3a5890603
Ref: Core and Builtins<174>-Footnote-15891409
Ref: Core and Builtins<174>-Footnote-25891474
Ref: Core and Builtins<174>-Footnote-35891539
Ref: Core and Builtins<174>-Footnote-45891581
Ref: Core and Builtins<174>-Footnote-55891646
Ref: Core and Builtins<174>-Footnote-65891711
Ref: Core and Builtins<174>-Footnote-75891776
Ref: Core and Builtins<174>-Footnote-85891841
Node: Library<176>5891906
Ref: whatsnew/changelog id9755892023
Ref: 1d3b5892023
Ref: Library<176>-Footnote-15894306
Ref: Library<176>-Footnote-25894371
Ref: Library<176>-Footnote-35894436
Ref: Library<176>-Footnote-45894501
Ref: Library<176>-Footnote-55894566
Ref: Library<176>-Footnote-65894631
Ref: Library<176>-Footnote-75894696
Ref: Library<176>-Footnote-85894761
Ref: Library<176>-Footnote-95894826
Ref: Library<176>-Footnote-105894891
Ref: Library<176>-Footnote-115894957
Ref: Library<176>-Footnote-125895023
Ref: Library<176>-Footnote-135895089
Ref: Library<176>-Footnote-145895155
Ref: Library<176>-Footnote-155895221
Ref: Library<176>-Footnote-165895287
Ref: Library<176>-Footnote-175895353
Ref: Library<176>-Footnote-185895419
Ref: Library<176>-Footnote-195895485
Node: Build<94>5895551
Ref: whatsnew/changelog id9765895637
Ref: 1d3c5895637
Ref: Build<94>-Footnote-15895802
Node: Python 3 5 0 beta 35895867
Ref: whatsnew/changelog python-3-5-0-beta-35895988
Ref: 1d3d5895988
Node: Core and Builtins<175>5896231
Ref: whatsnew/changelog id9775896330
Ref: 1d3e5896330
Ref: Core and Builtins<175>-Footnote-15897657
Ref: Core and Builtins<175>-Footnote-25897722
Ref: Core and Builtins<175>-Footnote-35897787
Ref: Core and Builtins<175>-Footnote-45897852
Ref: Core and Builtins<175>-Footnote-55897894
Ref: Core and Builtins<175>-Footnote-65897959
Node: Library<177>5898024
Ref: whatsnew/changelog id9785898141
Ref: 1d3f5898141
Ref: Library<177>-Footnote-15900103
Ref: Library<177>-Footnote-25900168
Ref: Library<177>-Footnote-35900233
Ref: Library<177>-Footnote-45900298
Ref: Library<177>-Footnote-55900363
Ref: Library<177>-Footnote-65900428
Ref: Library<177>-Footnote-75900493
Ref: Library<177>-Footnote-85900558
Ref: Library<177>-Footnote-95900623
Ref: Library<177>-Footnote-105900688
Ref: Library<177>-Footnote-115900754
Ref: Library<177>-Footnote-125900820
Ref: Library<177>-Footnote-135900886
Ref: Library<177>-Footnote-145900952
Ref: Library<177>-Footnote-155901018
Ref: Library<177>-Footnote-165901084
Ref: Library<177>-Footnote-175901150
Ref: Library<177>-Footnote-185901216
Node: Tests<86>5901282
Ref: whatsnew/changelog id9795901394
Ref: 1d405901394
Ref: Tests<86>-Footnote-15901676
Ref: Tests<86>-Footnote-25901741
Node: Documentation<81>5901806
Ref: whatsnew/changelog id9805901915
Ref: 1d415901915
Ref: Documentation<81>-Footnote-15902259
Ref: Documentation<81>-Footnote-25902324
Node: Build<95>5902389
Ref: whatsnew/changelog id9815902480
Ref: 1d425902480
Ref: Build<95>-Footnote-15902645
Node: Python 3 5 0 beta 25902710
Ref: whatsnew/changelog python-3-5-0-beta-25902831
Ref: 1d435902831
Node: Core and Builtins<176>5902998
Ref: whatsnew/changelog id9825903097
Ref: 1d445903097
Ref: Core and Builtins<176>-Footnote-15903850
Ref: Core and Builtins<176>-Footnote-25903915
Ref: Core and Builtins<176>-Footnote-35903980
Ref: Core and Builtins<176>-Footnote-45904045
Ref: Core and Builtins<176>-Footnote-55904110
Node: Library<178>5904175
Ref: whatsnew/changelog id9835904274
Ref: 1d455904274
Ref: Library<178>-Footnote-15904981
Ref: Library<178>-Footnote-25905046
Ref: Library<178>-Footnote-35905111
Ref: Library<178>-Footnote-45905153
Ref: Library<178>-Footnote-55905217
Ref: Library<178>-Footnote-65905282
Ref: Library<178>-Footnote-75905347
Node: Python 3 5 0 beta 15905412
Ref: whatsnew/changelog python-3-5-0-beta-15905534
Ref: 1d465905534
Node: Core and Builtins<177>5905807
Ref: whatsnew/changelog id9845905906
Ref: 1d475905906
Ref: Core and Builtins<177>-Footnote-15907779
Ref: Core and Builtins<177>-Footnote-25907844
Ref: Core and Builtins<177>-Footnote-35907909
Ref: Core and Builtins<177>-Footnote-45907974
Ref: Core and Builtins<177>-Footnote-55908039
Ref: Core and Builtins<177>-Footnote-65908104
Ref: Core and Builtins<177>-Footnote-75908169
Ref: Core and Builtins<177>-Footnote-85908234
Ref: Core and Builtins<177>-Footnote-95908299
Ref: Core and Builtins<177>-Footnote-105908364
Ref: Core and Builtins<177>-Footnote-115908429
Ref: Core and Builtins<177>-Footnote-125908495
Ref: Core and Builtins<177>-Footnote-135908561
Ref: Core and Builtins<177>-Footnote-145908627
Ref: Core and Builtins<177>-Footnote-155908693
Ref: Core and Builtins<177>-Footnote-165908759
Ref: Core and Builtins<177>-Footnote-175908825
Ref: Core and Builtins<177>-Footnote-185908890
Ref: Core and Builtins<177>-Footnote-195908956
Node: Library<179>5909022
Ref: whatsnew/changelog id9855909138
Ref: 1d485909138
Ref: Library<179>-Footnote-15916800
Ref: Library<179>-Footnote-25916865
Ref: Library<179>-Footnote-35916930
Ref: Library<179>-Footnote-45916995
Ref: Library<179>-Footnote-55917060
Ref: Library<179>-Footnote-65917125
Ref: Library<179>-Footnote-75917190
Ref: Library<179>-Footnote-85917255
Ref: Library<179>-Footnote-95917320
Ref: Library<179>-Footnote-105917385
Ref: Library<179>-Footnote-115917450
Ref: Library<179>-Footnote-125917516
Ref: Library<179>-Footnote-135917582
Ref: Library<179>-Footnote-145917648
Ref: Library<179>-Footnote-155917713
Ref: Library<179>-Footnote-165917779
Ref: Library<179>-Footnote-175917845
Ref: Library<179>-Footnote-185917911
Ref: Library<179>-Footnote-195917977
Ref: Library<179>-Footnote-205918043
Ref: Library<179>-Footnote-215918109
Ref: Library<179>-Footnote-225918175
Ref: Library<179>-Footnote-235918241
Ref: Library<179>-Footnote-245918307
Ref: Library<179>-Footnote-255918373
Ref: Library<179>-Footnote-265918438
Ref: Library<179>-Footnote-275918504
Ref: Library<179>-Footnote-285918570
Ref: Library<179>-Footnote-295918636
Ref: Library<179>-Footnote-305918702
Ref: Library<179>-Footnote-315918768
Ref: Library<179>-Footnote-325918834
Ref: Library<179>-Footnote-335918900
Ref: Library<179>-Footnote-345918966
Ref: Library<179>-Footnote-355919032
Ref: Library<179>-Footnote-365919098
Ref: Library<179>-Footnote-375919164
Ref: Library<179>-Footnote-385919230
Ref: Library<179>-Footnote-395919296
Ref: Library<179>-Footnote-405919362
Ref: Library<179>-Footnote-415919428
Ref: Library<179>-Footnote-425919493
Ref: Library<179>-Footnote-435919559
Ref: Library<179>-Footnote-445919625
Ref: Library<179>-Footnote-455919691
Ref: Library<179>-Footnote-465919757
Ref: Library<179>-Footnote-475919823
Ref: Library<179>-Footnote-485919889
Ref: Library<179>-Footnote-495919955
Ref: Library<179>-Footnote-505920021
Ref: Library<179>-Footnote-515920087
Ref: Library<179>-Footnote-525920153
Ref: Library<179>-Footnote-535920219
Ref: Library<179>-Footnote-545920285
Ref: Library<179>-Footnote-555920351
Ref: Library<179>-Footnote-565920417
Node: IDLE<66>5920483
Ref: whatsnew/changelog id9865920586
Ref: 1d495920586
Ref: IDLE<66>-Footnote-15920755
Node: Tests<87>5920820
Ref: whatsnew/changelog id9875920928
Ref: 1d4a5920928
Ref: Tests<87>-Footnote-15921226
Ref: Tests<87>-Footnote-25921291
Node: Documentation<82>5921355
Ref: whatsnew/changelog id9885921470
Ref: 1d4b5921470
Ref: Documentation<82>-Footnote-15921877
Ref: Documentation<82>-Footnote-25921942
Ref: Documentation<82>-Footnote-35922007
Node: Tools/Demos<51>5922072
Ref: whatsnew/changelog id9895922169
Ref: 1d4c5922169
Ref: Tools/Demos<51>-Footnote-15922688
Ref: Tools/Demos<51>-Footnote-25922753
Ref: Tools/Demos<51>-Footnote-35922818
Ref: Tools/Demos<51>-Footnote-45922883
Node: Python 3 5 0 alpha 45922948
Ref: whatsnew/changelog python-3-5-0-alpha-45923071
Ref: 1d4d5923071
Node: Core and Builtins<178>5923332
Ref: whatsnew/changelog id9905923432
Ref: 1d4e5923432
Ref: Core and Builtins<178>-Footnote-15924801
Ref: Core and Builtins<178>-Footnote-25924866
Ref: Core and Builtins<178>-Footnote-35924908
Ref: Core and Builtins<178>-Footnote-45924973
Ref: Core and Builtins<178>-Footnote-55925038
Ref: Core and Builtins<178>-Footnote-65925080
Ref: Core and Builtins<178>-Footnote-75925145
Ref: Core and Builtins<178>-Footnote-85925210
Ref: Core and Builtins<178>-Footnote-95925275
Ref: Core and Builtins<178>-Footnote-105925340
Ref: Core and Builtins<178>-Footnote-115925406
Node: Library<180>5925472
Ref: whatsnew/changelog id9915925590
Ref: 1d4f5925590
Ref: Library<180>-Footnote-15932295
Ref: Library<180>-Footnote-25932360
Ref: Library<180>-Footnote-35932425
Ref: Library<180>-Footnote-45932489
Ref: Library<180>-Footnote-55932554
Ref: Library<180>-Footnote-65932619
Ref: Library<180>-Footnote-75932683
Ref: Library<180>-Footnote-85932748
Ref: Library<180>-Footnote-95932813
Ref: Library<180>-Footnote-105932878
Ref: Library<180>-Footnote-115932944
Ref: Library<180>-Footnote-125933010
Ref: Library<180>-Footnote-135933076
Ref: Library<180>-Footnote-145933142
Ref: Library<180>-Footnote-155933208
Ref: Library<180>-Footnote-165933274
Ref: Library<180>-Footnote-175933340
Ref: Library<180>-Footnote-185933406
Ref: Library<180>-Footnote-195933472
Ref: Library<180>-Footnote-205933538
Ref: Library<180>-Footnote-215933604
Ref: Library<180>-Footnote-225933670
Ref: Library<180>-Footnote-235933736
Ref: Library<180>-Footnote-245933802
Ref: Library<180>-Footnote-255933868
Ref: Library<180>-Footnote-265933934
Ref: Library<180>-Footnote-275934000
Ref: Library<180>-Footnote-285934066
Ref: Library<180>-Footnote-295934132
Ref: Library<180>-Footnote-305934198
Ref: Library<180>-Footnote-315934263
Ref: Library<180>-Footnote-325934329
Ref: Library<180>-Footnote-335934395
Ref: Library<180>-Footnote-345934461
Ref: Library<180>-Footnote-355934527
Ref: Library<180>-Footnote-365934593
Ref: Library<180>-Footnote-375934659
Ref: Library<180>-Footnote-385934725
Ref: Library<180>-Footnote-395934791
Ref: Library<180>-Footnote-405934857
Ref: Library<180>-Footnote-415934923
Ref: Library<180>-Footnote-425934989
Ref: Library<180>-Footnote-435935032
Ref: Library<180>-Footnote-445935098
Ref: Library<180>-Footnote-455935164
Ref: Library<180>-Footnote-465935230
Ref: Library<180>-Footnote-475935296
Ref: Library<180>-Footnote-485935362
Node: Build<96>5935428
Ref: whatsnew/changelog id9925935533
Ref: 1d505935533
Ref: Build<96>-Footnote-15935818
Ref: Build<96>-Footnote-25935883
Node: Tests<88>5935948
Ref: whatsnew/changelog id9935936056
Ref: 1d515936056
Ref: Tests<88>-Footnote-15936357
Ref: Tests<88>-Footnote-25936422
Node: Tools/Demos<52>5936487
Ref: whatsnew/changelog id9945936595
Ref: 1d525936595
Ref: Tools/Demos<52>-Footnote-15937629
Ref: Tools/Demos<52>-Footnote-25937694
Ref: Tools/Demos<52>-Footnote-35937759
Ref: Tools/Demos<52>-Footnote-45937824
Ref: Tools/Demos<52>-Footnote-55937889
Ref: Tools/Demos<52>-Footnote-65937954
Node: C API<76>5938019
Ref: whatsnew/changelog id9955938109
Ref: 1d535938109
Ref: C API<76>-Footnote-15938264
Node: Python 3 5 0 alpha 35938329
Ref: whatsnew/changelog python-3-5-0-alpha-35938453
Ref: 1d545938453
Node: Core and Builtins<179>5938694
Ref: whatsnew/changelog id9965938794
Ref: 1d555938794
Ref: Core and Builtins<179>-Footnote-15939590
Ref: Core and Builtins<179>-Footnote-25939655
Ref: Core and Builtins<179>-Footnote-35939720
Ref: Core and Builtins<179>-Footnote-45939785
Ref: Core and Builtins<179>-Footnote-55939850
Ref: Core and Builtins<179>-Footnote-65939915
Node: Library<181>5939980
Ref: whatsnew/changelog id9975940098
Ref: 1d565940098
Ref: Library<181>-Footnote-15946534
Ref: Library<181>-Footnote-25946599
Ref: Library<181>-Footnote-35946664
Ref: Library<181>-Footnote-45946729
Ref: Library<181>-Footnote-55946794
Ref: Library<181>-Footnote-65946859
Ref: Library<181>-Footnote-75946924
Ref: Library<181>-Footnote-85946989
Ref: Library<181>-Footnote-95947054
Ref: Library<181>-Footnote-105947119
Ref: Library<181>-Footnote-115947185
Ref: Library<181>-Footnote-125947251
Ref: Library<181>-Footnote-135947317
Ref: Library<181>-Footnote-145947383
Ref: Library<181>-Footnote-155947448
Ref: Library<181>-Footnote-165947514
Ref: Library<181>-Footnote-175947580
Ref: Library<181>-Footnote-185947646
Ref: Library<181>-Footnote-195947712
Ref: Library<181>-Footnote-205947778
Ref: Library<181>-Footnote-215947844
Ref: Library<181>-Footnote-225947910
Ref: Library<181>-Footnote-235947976
Ref: Library<181>-Footnote-245948042
Ref: Library<181>-Footnote-255948108
Ref: Library<181>-Footnote-265948174
Ref: Library<181>-Footnote-275948240
Ref: Library<181>-Footnote-285948306
Ref: Library<181>-Footnote-295948372
Ref: Library<181>-Footnote-305948438
Ref: Library<181>-Footnote-315948503
Ref: Library<181>-Footnote-325948569
Ref: Library<181>-Footnote-335948635
Ref: Library<181>-Footnote-345948701
Ref: Library<181>-Footnote-355948766
Ref: Library<181>-Footnote-365948832
Ref: Library<181>-Footnote-375948898
Ref: Library<181>-Footnote-385948964
Ref: Library<181>-Footnote-395949030
Ref: Library<181>-Footnote-405949096
Ref: Library<181>-Footnote-415949162
Ref: Library<181>-Footnote-425949228
Node: Build<97>5949294
Ref: whatsnew/changelog id9985949399
Ref: 1d575949399
Ref: Build<97>-Footnote-15949544
Node: Tests<89>5949609
Ref: whatsnew/changelog id9995949717
Ref: 1d585949717
Ref: Tests<89>-Footnote-15949942
Ref: Tests<89>-Footnote-25950007
Node: Tools/Demos<53>5950072
Ref: whatsnew/changelog id10005950162
Ref: 1d595950162
Ref: Tools/Demos<53>-Footnote-15950431
Node: Python 3 5 0 alpha 25950496
Ref: whatsnew/changelog python-3-5-0-alpha-25950620
Ref: 1d5a5950620
Node: Core and Builtins<180>5950853
Ref: whatsnew/changelog id10015950953
Ref: 1d5b5950953
Ref: Core and Builtins<180>-Footnote-15951251
Node: Library<182>5951316
Ref: whatsnew/changelog id10025951434
Ref: 1d5c5951434
Ref: Library<182>-Footnote-15955751
Ref: Library<182>-Footnote-25955816
Ref: Library<182>-Footnote-35955858
Ref: Library<182>-Footnote-45955923
Ref: Library<182>-Footnote-55955988
Ref: Library<182>-Footnote-65956053
Ref: Library<182>-Footnote-75956118
Ref: Library<182>-Footnote-85956183
Ref: Library<182>-Footnote-95956248
Ref: Library<182>-Footnote-105956312
Ref: Library<182>-Footnote-115956378
Ref: Library<182>-Footnote-125956444
Ref: Library<182>-Footnote-135956510
Ref: Library<182>-Footnote-145956576
Ref: Library<182>-Footnote-155956642
Ref: Library<182>-Footnote-165956708
Ref: Library<182>-Footnote-175956773
Ref: Library<182>-Footnote-185956840
Ref: Library<182>-Footnote-195956905
Ref: Library<182>-Footnote-205956971
Ref: Library<182>-Footnote-215957036
Ref: Library<182>-Footnote-225957102
Ref: Library<182>-Footnote-235957168
Ref: Library<182>-Footnote-245957234
Ref: Library<182>-Footnote-255957300
Ref: Library<182>-Footnote-265957366
Ref: Library<182>-Footnote-275957432
Ref: Library<182>-Footnote-285957498
Ref: Library<182>-Footnote-295957564
Ref: Library<182>-Footnote-305957630
Ref: Library<182>-Footnote-315957696
Ref: Library<182>-Footnote-325957762
Ref: Library<182>-Footnote-335957828
Ref: Library<182>-Footnote-345957894
Ref: Library<182>-Footnote-355957960
Ref: Library<182>-Footnote-365958026
Ref: Library<182>-Footnote-375958092
Node: Build<98>5958158
Ref: whatsnew/changelog id10035958263
Ref: 1d5d5958263
Ref: Build<98>-Footnote-15958534
Ref: Build<98>-Footnote-25958599
Node: C API<77>5958664
Ref: whatsnew/changelog id10045958768
Ref: 1d5e5958768
Ref: C API<77>-Footnote-15958950
Node: Windows<80>5959015
Ref: whatsnew/changelog id10055959101
Ref: 1d5f5959101
Ref: Windows<80>-Footnote-15959398
Ref: Windows<80>-Footnote-25959463
Ref: Windows<80>-Footnote-35959505
Node: Python 3 5 0 alpha 15959570
Ref: whatsnew/changelog python-3-5-0-alpha-15959665
Ref: 1d605959665
Node: Core and Builtins<181>5960004
Ref: whatsnew/changelog id10065960104
Ref: 1d615960104
Ref: Core and Builtins<181>-Footnote-15970029
Ref: Core and Builtins<181>-Footnote-25970094
Ref: Core and Builtins<181>-Footnote-35970159
Ref: Core and Builtins<181>-Footnote-45970224
Ref: Core and Builtins<181>-Footnote-55970289
Ref: Core and Builtins<181>-Footnote-65970354
Ref: Core and Builtins<181>-Footnote-75970419
Ref: Core and Builtins<181>-Footnote-85970484
Ref: Core and Builtins<181>-Footnote-95970549
Ref: Core and Builtins<181>-Footnote-105970614
Ref: Core and Builtins<181>-Footnote-115970680
Ref: Core and Builtins<181>-Footnote-125970746
Ref: Core and Builtins<181>-Footnote-135970812
Ref: Core and Builtins<181>-Footnote-145970878
Ref: Core and Builtins<181>-Footnote-155970944
Ref: Core and Builtins<181>-Footnote-165971010
Ref: Core and Builtins<181>-Footnote-175971076
Ref: Core and Builtins<181>-Footnote-185971142
Ref: Core and Builtins<181>-Footnote-195971208
Ref: Core and Builtins<181>-Footnote-205971274
Ref: Core and Builtins<181>-Footnote-215971340
Ref: Core and Builtins<181>-Footnote-225971406
Ref: Core and Builtins<181>-Footnote-235971472
Ref: Core and Builtins<181>-Footnote-245971538
Ref: Core and Builtins<181>-Footnote-255971604
Ref: Core and Builtins<181>-Footnote-265971670
Ref: Core and Builtins<181>-Footnote-275971736
Ref: Core and Builtins<181>-Footnote-285971802
Ref: Core and Builtins<181>-Footnote-295971868
Ref: Core and Builtins<181>-Footnote-305971934
Ref: Core and Builtins<181>-Footnote-315972000
Ref: Core and Builtins<181>-Footnote-325972066
Ref: Core and Builtins<181>-Footnote-335972132
Ref: Core and Builtins<181>-Footnote-345972200
Ref: Core and Builtins<181>-Footnote-355972266
Ref: Core and Builtins<181>-Footnote-365972332
Ref: Core and Builtins<181>-Footnote-375972398
Ref: Core and Builtins<181>-Footnote-385972464
Ref: Core and Builtins<181>-Footnote-395972530
Ref: Core and Builtins<181>-Footnote-405972596
Ref: Core and Builtins<181>-Footnote-415972662
Ref: Core and Builtins<181>-Footnote-425972728
Ref: Core and Builtins<181>-Footnote-435972794
Ref: Core and Builtins<181>-Footnote-445972860
Ref: Core and Builtins<181>-Footnote-455972926
Ref: Core and Builtins<181>-Footnote-465972992
Ref: Core and Builtins<181>-Footnote-475973058
Ref: Core and Builtins<181>-Footnote-485973124
Ref: Core and Builtins<181>-Footnote-495973190
Ref: Core and Builtins<181>-Footnote-505973256
Ref: Core and Builtins<181>-Footnote-515973322
Ref: Core and Builtins<181>-Footnote-525973388
Ref: Core and Builtins<181>-Footnote-535973454
Ref: Core and Builtins<181>-Footnote-545973520
Ref: Core and Builtins<181>-Footnote-555973586
Ref: Core and Builtins<181>-Footnote-565973652
Ref: Core and Builtins<181>-Footnote-575973718
Ref: Core and Builtins<181>-Footnote-585973784
Ref: Core and Builtins<181>-Footnote-595973850
Ref: Core and Builtins<181>-Footnote-605973916
Ref: Core and Builtins<181>-Footnote-615973982
Ref: Core and Builtins<181>-Footnote-625974048
Ref: Core and Builtins<181>-Footnote-635974114
Ref: Core and Builtins<181>-Footnote-645974180
Ref: Core and Builtins<181>-Footnote-655974246
Ref: Core and Builtins<181>-Footnote-665974312
Ref: Core and Builtins<181>-Footnote-675974377
Ref: Core and Builtins<181>-Footnote-685974443
Ref: Core and Builtins<181>-Footnote-695974509
Ref: Core and Builtins<181>-Footnote-705974575
Ref: Core and Builtins<181>-Footnote-715974641
Ref: Core and Builtins<181>-Footnote-725974707
Ref: Core and Builtins<181>-Footnote-735974772
Node: Library<183>5974838
Ref: whatsnew/changelog id10075974955
Ref: 1d625974955
Ref: Library<183>-Footnote-16027486
Ref: Library<183>-Footnote-26027551
Ref: Library<183>-Footnote-36027616
Ref: Library<183>-Footnote-46027681
Ref: Library<183>-Footnote-56027746
Ref: Library<183>-Footnote-66027811
Ref: Library<183>-Footnote-76027876
Ref: Library<183>-Footnote-86027941
Ref: Library<183>-Footnote-96028006
Ref: Library<183>-Footnote-106028071
Ref: Library<183>-Footnote-116028137
Ref: Library<183>-Footnote-126028203
Ref: Library<183>-Footnote-136028269
Ref: Library<183>-Footnote-146028335
Ref: Library<183>-Footnote-156028401
Ref: Library<183>-Footnote-166028467
Ref: Library<183>-Footnote-176028533
Ref: Library<183>-Footnote-186028599
Ref: Library<183>-Footnote-196028665
Ref: Library<183>-Footnote-206028731
Ref: Library<183>-Footnote-216028797
Ref: Library<183>-Footnote-226028863
Ref: Library<183>-Footnote-236028929
Ref: Library<183>-Footnote-246028995
Ref: Library<183>-Footnote-256029061
Ref: Library<183>-Footnote-266029127
Ref: Library<183>-Footnote-276029193
Ref: Library<183>-Footnote-286029259
Ref: Library<183>-Footnote-296029325
Ref: Library<183>-Footnote-306029391
Ref: Library<183>-Footnote-316029457
Ref: Library<183>-Footnote-326029523
Ref: Library<183>-Footnote-336029589
Ref: Library<183>-Footnote-346029655
Ref: Library<183>-Footnote-356029721
Ref: Library<183>-Footnote-366029787
Ref: Library<183>-Footnote-376029853
Ref: Library<183>-Footnote-386029919
Ref: Library<183>-Footnote-396029985
Ref: Library<183>-Footnote-406030051
Ref: Library<183>-Footnote-416030117
Ref: Library<183>-Footnote-426030183
Ref: Library<183>-Footnote-436030249
Ref: Library<183>-Footnote-446030315
Ref: Library<183>-Footnote-456030381
Ref: Library<183>-Footnote-466030447
Ref: Library<183>-Footnote-476030513
Ref: Library<183>-Footnote-486030579
Ref: Library<183>-Footnote-496030645
Ref: Library<183>-Footnote-506030711
Ref: Library<183>-Footnote-516030777
Ref: Library<183>-Footnote-526030843
Ref: Library<183>-Footnote-536030909
Ref: Library<183>-Footnote-546030975
Ref: Library<183>-Footnote-556031041
Ref: Library<183>-Footnote-566031109
Ref: Library<183>-Footnote-576031175
Ref: Library<183>-Footnote-586031241
Ref: Library<183>-Footnote-596031307
Ref: Library<183>-Footnote-606031373
Ref: Library<183>-Footnote-616031439
Ref: Library<183>-Footnote-626031495
Ref: Library<183>-Footnote-636031561
Ref: Library<183>-Footnote-646031627
Ref: Library<183>-Footnote-656031693
Ref: Library<183>-Footnote-666031759
Ref: Library<183>-Footnote-676031825
Ref: Library<183>-Footnote-686031891
Ref: Library<183>-Footnote-696031957
Ref: Library<183>-Footnote-706032023
Ref: Library<183>-Footnote-716032089
Ref: Library<183>-Footnote-726032155
Ref: Library<183>-Footnote-736032221
Ref: Library<183>-Footnote-746032287
Ref: Library<183>-Footnote-756032353
Ref: Library<183>-Footnote-766032419
Ref: Library<183>-Footnote-776032485
Ref: Library<183>-Footnote-786032551
Ref: Library<183>-Footnote-796032617
Ref: Library<183>-Footnote-806032683
Ref: Library<183>-Footnote-816032749
Ref: Library<183>-Footnote-826032815
Ref: Library<183>-Footnote-836032881
Ref: Library<183>-Footnote-846032947
Ref: Library<183>-Footnote-856033013
Ref: Library<183>-Footnote-866033079
Ref: Library<183>-Footnote-876033145
Ref: Library<183>-Footnote-886033211
Ref: Library<183>-Footnote-896033277
Ref: Library<183>-Footnote-906033343
Ref: Library<183>-Footnote-916033409
Ref: Library<183>-Footnote-926033475
Ref: Library<183>-Footnote-936033541
Ref: Library<183>-Footnote-946033607
Ref: Library<183>-Footnote-956033673
Ref: Library<183>-Footnote-966033739
Ref: Library<183>-Footnote-976033804
Ref: Library<183>-Footnote-986033870
Ref: Library<183>-Footnote-996033936
Ref: Library<183>-Footnote-1006034002
Ref: Library<183>-Footnote-1016034068
Ref: Library<183>-Footnote-1026034135
Ref: Library<183>-Footnote-1036034202
Ref: Library<183>-Footnote-1046034269
Ref: Library<183>-Footnote-1056034336
Ref: Library<183>-Footnote-1066034403
Ref: Library<183>-Footnote-1076034470
Ref: Library<183>-Footnote-1086034536
Ref: Library<183>-Footnote-1096034602
Ref: Library<183>-Footnote-1106034669
Ref: Library<183>-Footnote-1116034736
Ref: Library<183>-Footnote-1126034803
Ref: Library<183>-Footnote-1136034870
Ref: Library<183>-Footnote-1146034937
Ref: Library<183>-Footnote-1156035004
Ref: Library<183>-Footnote-1166035071
Ref: Library<183>-Footnote-1176035138
Ref: Library<183>-Footnote-1186035205
Ref: Library<183>-Footnote-1196035272
Ref: Library<183>-Footnote-1206035339
Ref: Library<183>-Footnote-1216035406
Ref: Library<183>-Footnote-1226035475
Ref: Library<183>-Footnote-1236035542
Ref: Library<183>-Footnote-1246035609
Ref: Library<183>-Footnote-1256035676
Ref: Library<183>-Footnote-1266035743
Ref: Library<183>-Footnote-1276035810
Ref: Library<183>-Footnote-1286035877
Ref: Library<183>-Footnote-1296035944
Ref: Library<183>-Footnote-1306036011
Ref: Library<183>-Footnote-1316036078
Ref: Library<183>-Footnote-1326036145
Ref: Library<183>-Footnote-1336036212
Ref: Library<183>-Footnote-1346036279
Ref: Library<183>-Footnote-1356036346
Ref: Library<183>-Footnote-1366036413
Ref: Library<183>-Footnote-1376036480
Ref: Library<183>-Footnote-1386036547
Ref: Library<183>-Footnote-1396036614
Ref: Library<183>-Footnote-1406036681
Ref: Library<183>-Footnote-1416036748
Ref: Library<183>-Footnote-1426036815
Ref: Library<183>-Footnote-1436036881
Ref: Library<183>-Footnote-1446036947
Ref: Library<183>-Footnote-1456037014
Ref: Library<183>-Footnote-1466037081
Ref: Library<183>-Footnote-1476037148
Ref: Library<183>-Footnote-1486037215
Ref: Library<183>-Footnote-1496037282
Ref: Library<183>-Footnote-1506037349
Ref: Library<183>-Footnote-1516037416
Ref: Library<183>-Footnote-1526037483
Ref: Library<183>-Footnote-1536037550
Ref: Library<183>-Footnote-1546037617
Ref: Library<183>-Footnote-1556037684
Ref: Library<183>-Footnote-1566037751
Ref: Library<183>-Footnote-1576037818
Ref: Library<183>-Footnote-1586037884
Ref: Library<183>-Footnote-1596037951
Ref: Library<183>-Footnote-1606038018
Ref: Library<183>-Footnote-1616038085
Ref: Library<183>-Footnote-1626038152
Ref: Library<183>-Footnote-1636038219
Ref: Library<183>-Footnote-1646038286
Ref: Library<183>-Footnote-1656038353
Ref: Library<183>-Footnote-1666038420
Ref: Library<183>-Footnote-1676038487
Ref: Library<183>-Footnote-1686038554
Ref: Library<183>-Footnote-1696038621
Ref: Library<183>-Footnote-1706038688
Ref: Library<183>-Footnote-1716038755
Ref: Library<183>-Footnote-1726038822
Ref: Library<183>-Footnote-1736038889
Ref: Library<183>-Footnote-1746038956
Ref: Library<183>-Footnote-1756039023
Ref: Library<183>-Footnote-1766039090
Ref: Library<183>-Footnote-1776039157
Ref: Library<183>-Footnote-1786039224
Ref: Library<183>-Footnote-1796039291
Ref: Library<183>-Footnote-1806039358
Ref: Library<183>-Footnote-1816039425
Ref: Library<183>-Footnote-1826039492
Ref: Library<183>-Footnote-1836039559
Ref: Library<183>-Footnote-1846039626
Ref: Library<183>-Footnote-1856039693
Ref: Library<183>-Footnote-1866039760
Ref: Library<183>-Footnote-1876039827
Ref: Library<183>-Footnote-1886039894
Ref: Library<183>-Footnote-1896039960
Ref: Library<183>-Footnote-1906040027
Ref: Library<183>-Footnote-1916040094
Ref: Library<183>-Footnote-1926040161
Ref: Library<183>-Footnote-1936040228
Ref: Library<183>-Footnote-1946040295
Ref: Library<183>-Footnote-1956040362
Ref: Library<183>-Footnote-1966040429
Ref: Library<183>-Footnote-1976040495
Ref: Library<183>-Footnote-1986040562
Ref: Library<183>-Footnote-1996040629
Ref: Library<183>-Footnote-2006040696
Ref: Library<183>-Footnote-2016040763
Ref: Library<183>-Footnote-2026040830
Ref: Library<183>-Footnote-2036040897
Ref: Library<183>-Footnote-2046040963
Ref: Library<183>-Footnote-2056041030
Ref: Library<183>-Footnote-2066041097
Ref: Library<183>-Footnote-2076041164
Ref: Library<183>-Footnote-2086041231
Ref: Library<183>-Footnote-2096041298
Ref: Library<183>-Footnote-2106041365
Ref: Library<183>-Footnote-2116041432
Ref: Library<183>-Footnote-2126041499
Ref: Library<183>-Footnote-2136041566
Ref: Library<183>-Footnote-2146041633
Ref: Library<183>-Footnote-2156041700
Ref: Library<183>-Footnote-2166041767
Ref: Library<183>-Footnote-2176041834
Ref: Library<183>-Footnote-2186041901
Ref: Library<183>-Footnote-2196041968
Ref: Library<183>-Footnote-2206042035
Ref: Library<183>-Footnote-2216042102
Ref: Library<183>-Footnote-2226042169
Ref: Library<183>-Footnote-2236042236
Ref: Library<183>-Footnote-2246042303
Ref: Library<183>-Footnote-2256042369
Ref: Library<183>-Footnote-2266042435
Ref: Library<183>-Footnote-2276042502
Ref: Library<183>-Footnote-2286042569
Ref: Library<183>-Footnote-2296042636
Ref: Library<183>-Footnote-2306042703
Ref: Library<183>-Footnote-2316042770
Ref: Library<183>-Footnote-2326042837
Ref: Library<183>-Footnote-2336042904
Ref: Library<183>-Footnote-2346042971
Ref: Library<183>-Footnote-2356043038
Ref: Library<183>-Footnote-2366043105
Ref: Library<183>-Footnote-2376043172
Ref: Library<183>-Footnote-2386043239
Ref: Library<183>-Footnote-2396043306
Ref: Library<183>-Footnote-2406043373
Ref: Library<183>-Footnote-2416043440
Ref: Library<183>-Footnote-2426043507
Ref: Library<183>-Footnote-2436043574
Ref: Library<183>-Footnote-2446043641
Ref: Library<183>-Footnote-2456043708
Ref: Library<183>-Footnote-2466043774
Ref: Library<183>-Footnote-2476043841
Ref: Library<183>-Footnote-2486043908
Ref: Library<183>-Footnote-2496043975
Ref: Library<183>-Footnote-2506044042
Ref: Library<183>-Footnote-2516044109
Ref: Library<183>-Footnote-2526044176
Ref: Library<183>-Footnote-2536044243
Ref: Library<183>-Footnote-2546044310
Ref: Library<183>-Footnote-2556044377
Ref: Library<183>-Footnote-2566044444
Ref: Library<183>-Footnote-2576044511
Ref: Library<183>-Footnote-2586044578
Ref: Library<183>-Footnote-2596044645
Ref: Library<183>-Footnote-2606044712
Ref: Library<183>-Footnote-2616044779
Ref: Library<183>-Footnote-2626044846
Ref: Library<183>-Footnote-2636044913
Ref: Library<183>-Footnote-2646044980
Ref: Library<183>-Footnote-2656045047
Ref: Library<183>-Footnote-2666045114
Ref: Library<183>-Footnote-2676045181
Ref: Library<183>-Footnote-2686045248
Ref: Library<183>-Footnote-2696045315
Ref: Library<183>-Footnote-2706045382
Ref: Library<183>-Footnote-2716045449
Ref: Library<183>-Footnote-2726045516
Ref: Library<183>-Footnote-2736045583
Ref: Library<183>-Footnote-2746045650
Ref: Library<183>-Footnote-2756045717
Ref: Library<183>-Footnote-2766045784
Ref: Library<183>-Footnote-2776045851
Ref: Library<183>-Footnote-2786045917
Ref: Library<183>-Footnote-2796045984
Ref: Library<183>-Footnote-2806046051
Ref: Library<183>-Footnote-2816046118
Ref: Library<183>-Footnote-2826046185
Ref: Library<183>-Footnote-2836046252
Ref: Library<183>-Footnote-2846046319
Ref: Library<183>-Footnote-2856046386
Ref: Library<183>-Footnote-2866046453
Ref: Library<183>-Footnote-2876046520
Ref: Library<183>-Footnote-2886046587
Ref: Library<183>-Footnote-2896046654
Ref: Library<183>-Footnote-2906046698
Ref: Library<183>-Footnote-2916046765
Ref: Library<183>-Footnote-2926046832
Ref: Library<183>-Footnote-2936046899
Ref: Library<183>-Footnote-2946046966
Ref: Library<183>-Footnote-2956047033
Ref: Library<183>-Footnote-2966047100
Ref: Library<183>-Footnote-2976047167
Ref: Library<183>-Footnote-2986047234
Ref: Library<183>-Footnote-2996047301
Ref: Library<183>-Footnote-3006047368
Ref: Library<183>-Footnote-3016047435
Ref: Library<183>-Footnote-3026047502
Ref: Library<183>-Footnote-3036047569
Ref: Library<183>-Footnote-3046047636
Ref: Library<183>-Footnote-3056047703
Ref: Library<183>-Footnote-3066047770
Ref: Library<183>-Footnote-3076047837
Ref: Library<183>-Footnote-3086047904
Ref: Library<183>-Footnote-3096047971
Ref: Library<183>-Footnote-3106048038
Ref: Library<183>-Footnote-3116048105
Ref: Library<183>-Footnote-3126048172
Ref: Library<183>-Footnote-3136048239
Ref: Library<183>-Footnote-3146048306
Ref: Library<183>-Footnote-3156048373
Ref: Library<183>-Footnote-3166048439
Ref: Library<183>-Footnote-3176048506
Ref: Library<183>-Footnote-3186048573
Ref: Library<183>-Footnote-3196048640
Ref: Library<183>-Footnote-3206048707
Ref: Library<183>-Footnote-3216048774
Ref: Library<183>-Footnote-3226048841
Ref: Library<183>-Footnote-3236048908
Ref: Library<183>-Footnote-3246048975
Ref: Library<183>-Footnote-3256049042
Ref: Library<183>-Footnote-3266049109
Ref: Library<183>-Footnote-3276049176
Ref: Library<183>-Footnote-3286049243
Ref: Library<183>-Footnote-3296049310
Ref: Library<183>-Footnote-3306049377
Ref: Library<183>-Footnote-3316049444
Ref: Library<183>-Footnote-3326049511
Ref: Library<183>-Footnote-3336049578
Ref: Library<183>-Footnote-3346049645
Ref: Library<183>-Footnote-3356049712
Ref: Library<183>-Footnote-3366049778
Ref: Library<183>-Footnote-3376049845
Ref: Library<183>-Footnote-3386049912
Ref: Library<183>-Footnote-3396049969
Ref: Library<183>-Footnote-3406050036
Ref: Library<183>-Footnote-3416050103
Ref: Library<183>-Footnote-3426050170
Ref: Library<183>-Footnote-3436050237
Ref: Library<183>-Footnote-3446050304
Ref: Library<183>-Footnote-3456050371
Ref: Library<183>-Footnote-3466050438
Ref: Library<183>-Footnote-3476050505
Ref: Library<183>-Footnote-3486050572
Ref: Library<183>-Footnote-3496050639
Ref: Library<183>-Footnote-3506050706
Ref: Library<183>-Footnote-3516050773
Ref: Library<183>-Footnote-3526050840
Ref: Library<183>-Footnote-3536050907
Ref: Library<183>-Footnote-3546050974
Ref: Library<183>-Footnote-3556051041
Ref: Library<183>-Footnote-3566051108
Ref: Library<183>-Footnote-3576051175
Ref: Library<183>-Footnote-3586051242
Ref: Library<183>-Footnote-3596051309
Ref: Library<183>-Footnote-3606051376
Ref: Library<183>-Footnote-3616051443
Ref: Library<183>-Footnote-3626051510
Ref: Library<183>-Footnote-3636051577
Ref: Library<183>-Footnote-3646051644
Ref: Library<183>-Footnote-3656051711
Ref: Library<183>-Footnote-3666051778
Ref: Library<183>-Footnote-3676051845
Ref: Library<183>-Footnote-3686051912
Ref: Library<183>-Footnote-3696051979
Ref: Library<183>-Footnote-3706052046
Ref: Library<183>-Footnote-3716052113
Ref: Library<183>-Footnote-3726052180
Ref: Library<183>-Footnote-3736052246
Ref: Library<183>-Footnote-3746052313
Ref: Library<183>-Footnote-3756052380
Ref: Library<183>-Footnote-3766052447
Ref: Library<183>-Footnote-3776052514
Ref: Library<183>-Footnote-3786052581
Ref: Library<183>-Footnote-3796052648
Ref: Library<183>-Footnote-3806052715
Ref: Library<183>-Footnote-3816052782
Ref: Library<183>-Footnote-3826052849
Ref: Library<183>-Footnote-3836052916
Ref: Library<183>-Footnote-3846052983
Ref: Library<183>-Footnote-3856053050
Ref: Library<183>-Footnote-3866053116
Ref: Library<183>-Footnote-3876053183
Ref: Library<183>-Footnote-3886053250
Ref: Library<183>-Footnote-3896053317
Ref: Library<183>-Footnote-3906053384
Ref: Library<183>-Footnote-3916053449
Ref: Library<183>-Footnote-3926053516
Ref: Library<183>-Footnote-3936053583
Ref: Library<183>-Footnote-3946053650
Ref: Library<183>-Footnote-3956053717
Ref: Library<183>-Footnote-3966053784
Ref: Library<183>-Footnote-3976053851
Ref: Library<183>-Footnote-3986053918
Node: IDLE<67>6053985
Ref: whatsnew/changelog id10086054089
Ref: 1d636054089
Ref: IDLE<67>-Footnote-16057587
Ref: IDLE<67>-Footnote-26057652
Ref: IDLE<67>-Footnote-36057717
Ref: IDLE<67>-Footnote-46057781
Ref: IDLE<67>-Footnote-56057846
Ref: IDLE<67>-Footnote-66057910
Ref: IDLE<67>-Footnote-76057975
Ref: IDLE<67>-Footnote-86058040
Ref: IDLE<67>-Footnote-96058105
Ref: IDLE<67>-Footnote-106058170
Ref: IDLE<67>-Footnote-116058236
Ref: IDLE<67>-Footnote-126058302
Ref: IDLE<67>-Footnote-136058368
Ref: IDLE<67>-Footnote-146058434
Ref: IDLE<67>-Footnote-156058500
Ref: IDLE<67>-Footnote-166058566
Ref: IDLE<67>-Footnote-176058632
Ref: IDLE<67>-Footnote-186058698
Ref: IDLE<67>-Footnote-196058764
Ref: IDLE<67>-Footnote-206058830
Ref: IDLE<67>-Footnote-216058896
Ref: IDLE<67>-Footnote-226058962
Ref: IDLE<67>-Footnote-236059028
Ref: IDLE<67>-Footnote-246059071
Ref: IDLE<67>-Footnote-256059137
Ref: IDLE<67>-Footnote-266059203
Node: Build<99>6059269
Ref: whatsnew/changelog id10096059370
Ref: 1d646059370
Ref: Build<99>-Footnote-16062804
Ref: Build<99>-Footnote-26062869
Ref: Build<99>-Footnote-36062934
Ref: Build<99>-Footnote-46062999
Ref: Build<99>-Footnote-56063064
Ref: Build<99>-Footnote-66063129
Ref: Build<99>-Footnote-76063194
Ref: Build<99>-Footnote-86063259
Ref: Build<99>-Footnote-96063324
Ref: Build<99>-Footnote-106063389
Ref: Build<99>-Footnote-116063455
Ref: Build<99>-Footnote-126063521
Ref: Build<99>-Footnote-136063587
Ref: Build<99>-Footnote-146063653
Ref: Build<99>-Footnote-156063719
Ref: Build<99>-Footnote-166063785
Ref: Build<99>-Footnote-176063851
Ref: Build<99>-Footnote-186063917
Ref: Build<99>-Footnote-196063983
Ref: Build<99>-Footnote-206064049
Ref: Build<99>-Footnote-216064115
Ref: Build<99>-Footnote-226064181
Ref: Build<99>-Footnote-236064247
Ref: Build<99>-Footnote-246064313
Ref: Build<99>-Footnote-256064379
Ref: Build<99>-Footnote-266064445
Node: C API<78>6064511
Ref: whatsnew/changelog id10106064621
Ref: 1d656064621
Ref: C API<78>-Footnote-16065988
Ref: C API<78>-Footnote-26066053
Ref: C API<78>-Footnote-36066118
Ref: C API<78>-Footnote-46066183
Ref: C API<78>-Footnote-56066248
Ref: C API<78>-Footnote-66066313
Ref: C API<78>-Footnote-76066378
Node: Documentation<83>6066443
Ref: whatsnew/changelog id10116066553
Ref: 1d666066553
Ref: Documentation<83>-Footnote-16068362
Ref: Documentation<83>-Footnote-26068427
Ref: Documentation<83>-Footnote-36068492
Ref: Documentation<83>-Footnote-46068557
Ref: Documentation<83>-Footnote-56068622
Ref: Documentation<83>-Footnote-66068686
Ref: Documentation<83>-Footnote-76068751
Ref: Documentation<83>-Footnote-86068816
Ref: Documentation<83>-Footnote-96068881
Ref: Documentation<83>-Footnote-106068946
Ref: Documentation<83>-Footnote-116069012
Node: Tests<90>6069078
Ref: whatsnew/changelog id10126069194
Ref: 1d676069194
Ref: Tests<90>-Footnote-16073387
Ref: Tests<90>-Footnote-26073452
Ref: Tests<90>-Footnote-36073517
Ref: Tests<90>-Footnote-46073582
Ref: Tests<90>-Footnote-56073647
Ref: Tests<90>-Footnote-66073712
Ref: Tests<90>-Footnote-76073777
Ref: Tests<90>-Footnote-86073842
Ref: Tests<90>-Footnote-96073907
Ref: Tests<90>-Footnote-106073972
Ref: Tests<90>-Footnote-116074038
Ref: Tests<90>-Footnote-126074104
Ref: Tests<90>-Footnote-136074170
Ref: Tests<90>-Footnote-146074236
Ref: Tests<90>-Footnote-156074301
Ref: Tests<90>-Footnote-166074367
Ref: Tests<90>-Footnote-176074433
Ref: Tests<90>-Footnote-186074499
Ref: Tests<90>-Footnote-196074565
Ref: Tests<90>-Footnote-206074631
Ref: Tests<90>-Footnote-216074697
Ref: Tests<90>-Footnote-226074763
Ref: Tests<90>-Footnote-236074829
Ref: Tests<90>-Footnote-246074895
Ref: Tests<90>-Footnote-256074961
Ref: Tests<90>-Footnote-266075027
Ref: Tests<90>-Footnote-276075093
Ref: Tests<90>-Footnote-286075159
Ref: Tests<90>-Footnote-296075225
Ref: Tests<90>-Footnote-306075291
Ref: Tests<90>-Footnote-316075357
Ref: Tests<90>-Footnote-326075423
Ref: Tests<90>-Footnote-336075489
Ref: Tests<90>-Footnote-346075555
Ref: Tests<90>-Footnote-356075621
Ref: Tests<90>-Footnote-366075687
Ref: Tests<90>-Footnote-376075753
Node: Tools/Demos<54>6075819
Ref: whatsnew/changelog id10136075929
Ref: 1d686075929
Ref: Tools/Demos<54>-Footnote-16077603
Ref: Tools/Demos<54>-Footnote-26077668
Ref: Tools/Demos<54>-Footnote-36077733
Ref: Tools/Demos<54>-Footnote-46077798
Ref: Tools/Demos<54>-Footnote-56077863
Ref: Tools/Demos<54>-Footnote-66077928
Ref: Tools/Demos<54>-Footnote-76077993
Ref: Tools/Demos<54>-Footnote-86078058
Ref: Tools/Demos<54>-Footnote-96078123
Ref: Tools/Demos<54>-Footnote-106078188
Ref: Tools/Demos<54>-Footnote-116078231
Ref: Tools/Demos<54>-Footnote-126078297
Ref: Tools/Demos<54>-Footnote-136078363
Node: Windows<81>6078429
Ref: whatsnew/changelog id10146078521
Ref: 1d696078521
Ref: Windows<81>-Footnote-16079734
Ref: Windows<81>-Footnote-26079799
Ref: Windows<81>-Footnote-36079864
Ref: Windows<81>-Footnote-46079929
Ref: Windows<81>-Footnote-56079994
Ref: Windows<81>-Footnote-66080059
Ref: Windows<81>-Footnote-76080124
Node: The Python Tutorial6080189
Ref: tutorial/index doc6080310
Ref: 1d6a6080310
Ref: tutorial/index the-python-tutorial6080310
Ref: 1d6b6080310
Ref: tutorial/index translation-repo6080310
Ref: 1d6c6080310
Ref: tutorial/index tutorial-index6080310
Ref: 1d6d6080310
Node: Whetting Your Appetite6083274
Ref: tutorial/appetite doc6083389
Ref: 1d716083389
Ref: tutorial/appetite tut-intro6083389
Ref: 1d726083389
Ref: tutorial/appetite whetting-your-appetite6083389
Ref: 1d736083389
Node: Using the Python Interpreter6087904
Ref: tutorial/interpreter doc6088062
Ref: 1d746088062
Ref: tutorial/interpreter translation-repo6088062
Ref: 1d756088062
Ref: tutorial/interpreter tut-using6088062
Ref: 1d766088062
Ref: tutorial/interpreter using-the-python-interpreter6088062
Ref: 1d776088062
Node: Invoking the Interpreter6088208
Ref: tutorial/interpreter invoking-the-interpreter6088341
Ref: 1d786088341
Ref: tutorial/interpreter tut-invoking6088341
Ref: 1d796088341
Ref: Invoking the Interpreter-Footnote-16091380
Node: Argument Passing6091576
Ref: tutorial/interpreter argument-passing6091678
Ref: 1d7d6091678
Ref: tutorial/interpreter tut-argpassing6091678
Ref: 1d7e6091678
Node: Interactive Mode6092574
Ref: tutorial/interpreter interactive-mode6092676
Ref: 1d7f6092676
Ref: tutorial/interpreter tut-interactive6092676
Ref: 10016092676
Node: The Interpreter and Its Environment6093694
Ref: tutorial/interpreter the-interpreter-and-its-environment6093827
Ref: 1d806093827
Ref: tutorial/interpreter tut-interp6093827
Ref: 1d816093827
Node: Source Code Encoding6093947
Ref: tutorial/interpreter source-code-encoding6094039
Ref: 1d826094039
Ref: tutorial/interpreter tut-source-encoding6094039
Ref: 1d836094039
Node: An Informal Introduction to Python6095275
Ref: tutorial/introduction doc6095434
Ref: 1d856095434
Ref: tutorial/introduction an-informal-introduction-to-python6095434
Ref: 1d866095434
Ref: tutorial/introduction translation-repo6095434
Ref: 1d876095434
Ref: tutorial/introduction tut-informal6095434
Ref: 1d886095434
Node: Using Python as a Calculator6096737
Ref: tutorial/introduction tut-calculator6096876
Ref: 1d896096876
Ref: tutorial/introduction using-python-as-a-calculator6096876
Ref: 1d8a6096876
Node: Numbers6097126
Ref: tutorial/introduction numbers6097211
Ref: 1d8b6097211
Ref: tutorial/introduction tut-numbers6097211
Ref: 1d8c6097211
Ref: Numbers-Footnote-16100165
Node: Text6100361
Ref: tutorial/introduction text6100460
Ref: 1d8e6100460
Ref: tutorial/introduction tut-strings6100460
Ref: 1d8f6100460
Ref: Text-Footnote-16108672
Node: Lists6108976
Ref: tutorial/introduction lists6109059
Ref: 1d946109059
Ref: tutorial/introduction tut-lists6109059
Ref: 1d956109059
Node: First Steps Towards Programming6112268
Ref: tutorial/introduction first-steps-towards-programming6112407
Ref: 1d986112407
Ref: tutorial/introduction tut-firststeps6112407
Ref: 1d996112407
Ref: First Steps Towards Programming-Footnote-16115505
Node: More Control Flow Tools6115562
Ref: tutorial/controlflow doc6115708
Ref: 1d9b6115708
Ref: tutorial/controlflow more-control-flow-tools6115708
Ref: 1d9c6115708
Ref: tutorial/controlflow translation-repo6115708
Ref: 1d9d6115708
Ref: tutorial/controlflow tut-morecontrol6115708
Ref: 1d9e6115708
Node: if Statements6116189
Ref: tutorial/controlflow if-statements6116285
Ref: 1d9f6116285
Ref: tutorial/controlflow tut-if6116285
Ref: 1da06116285
Node: for Statements6117311
Ref: tutorial/controlflow for-statements6117434
Ref: 1da36117434
Ref: tutorial/controlflow tut-for6117434
Ref: 1da46117434
Node: The range Function6118799
Ref: tutorial/controlflow the-range-function6118938
Ref: 1da56118938
Ref: tutorial/controlflow tut-range6118938
Ref: 1da66118938
Node: break and continue Statements6121076
Ref: tutorial/controlflow break-and-continue-statements6121222
Ref: 1da96121222
Ref: tutorial/controlflow tut-break6121222
Ref: 1daa6121222
Ref: tutorial/controlflow tut-for-else6122202
Ref: 1dab6122202
Node: else Clauses on Loops6122203
Ref: tutorial/controlflow break-and-continue-statements-and-else-clauses-on-loops6122346
Ref: 1dac6122346
Ref: tutorial/controlflow else-clauses-on-loops6122346
Ref: 1dad6122346
Node: pass Statements6124596
Ref: tutorial/controlflow pass-statements6124726
Ref: 1daf6124726
Ref: tutorial/controlflow tut-pass6124726
Ref: 1db06124726
Node: match Statements6125785
Ref: tutorial/controlflow match-statements6125912
Ref: 1db36125912
Ref: tutorial/controlflow tut-match6125912
Ref: 1da26125912
Ref: match Statements-Footnote-16132586
Node: Defining Functions6132628
Ref: tutorial/controlflow defining-functions6132766
Ref: 1db46132766
Ref: tutorial/controlflow tut-functions6132766
Ref: 1db56132766
Ref: Defining Functions-Footnote-16137790
Node: More on Defining Functions6137988
Ref: tutorial/controlflow more-on-defining-functions6138133
Ref: 1db86138133
Ref: tutorial/controlflow tut-defining6138133
Ref: 1db96138133
Node: Default Argument Values6138540
Ref: tutorial/controlflow default-argument-values6138652
Ref: 1dba6138652
Ref: tutorial/controlflow tut-defaultargs6138652
Ref: 1dbb6138652
Node: Keyword Arguments6140672
Ref: tutorial/controlflow keyword-arguments6140811
Ref: 1dbc6140811
Ref: tutorial/controlflow tut-keywordargs6140811
Ref: 1dbd6140811
Node: Special parameters6144550
Ref: tutorial/controlflow special-parameters6144690
Ref: 1dbf6144690
Node: Positional-or-Keyword Arguments6145827
Ref: tutorial/controlflow positional-or-keyword-arguments6145948
Ref: 1dc06145948
Node: Positional-Only Parameters6146162
Ref: tutorial/controlflow positional-only-parameters6146314
Ref: 1dc16146314
Node: Keyword-Only Arguments6146948
Ref: tutorial/controlflow keyword-only-arguments6147086
Ref: 1dc26147086
Node: Function Examples6147337
Ref: tutorial/controlflow function-examples6147454
Ref: 1dc36147454
Node: Recap6150524
Ref: tutorial/controlflow recap6150610
Ref: 1dc46150610
Node: Arbitrary Argument Lists6151471
Ref: tutorial/controlflow arbitrary-argument-lists6151618
Ref: 1dc56151618
Ref: tutorial/controlflow tut-arbitraryargs6151618
Ref: 1dc66151618
Node: Unpacking Argument Lists6152654
Ref: tutorial/controlflow tut-unpacking-arguments6152801
Ref: 1dc76152801
Ref: tutorial/controlflow unpacking-argument-lists6152801
Ref: 1dc86152801
Node: Lambda Expressions6154034
Ref: tutorial/controlflow lambda-expressions6154178
Ref: 1dc96154178
Ref: tutorial/controlflow tut-lambda6154178
Ref: 1dca6154178
Node: Documentation Strings6155276
Ref: tutorial/controlflow documentation-strings6155416
Ref: 1dcb6155416
Ref: tutorial/controlflow tut-docstrings6155416
Ref: 1db66155416
Node: Function Annotations6156759
Ref: tutorial/controlflow function-annotations6156872
Ref: 1dcc6156872
Ref: tutorial/controlflow tut-annotations6156872
Ref: 1dcd6156872
Ref: Function Annotations-Footnote-16158088
Ref: Function Annotations-Footnote-26158130
Node: Intermezzo Coding Style6158172
Ref: tutorial/controlflow intermezzo-coding-style6158290
Ref: 1dd06158290
Ref: tutorial/controlflow tut-codingstyle6158290
Ref: 1dd16158290
Ref: Intermezzo Coding Style-Footnote-16160452
Node: Data Structures6160494
Ref: tutorial/datastructures doc6160616
Ref: 1dd36160616
Ref: tutorial/datastructures data-structures6160616
Ref: 1dd46160616
Ref: tutorial/datastructures translation-repo6160616
Ref: 1dd56160616
Ref: tutorial/datastructures tut-structures6160616
Ref: 1da86160616
Node: More on Lists6160961
Ref: tutorial/datastructures more-on-lists6161052
Ref: 1dd66161052
Ref: tutorial/datastructures tut-morelists6161052
Ref: 1dd76161052
Ref: More on Lists-Footnote-16164825
Node: Using Lists as Stacks6164962
Ref: tutorial/datastructures tut-lists-as-stacks6165063
Ref: 1dd96165063
Ref: tutorial/datastructures using-lists-as-stacks6165063
Ref: 1dda6165063
Node: Using Lists as Queues6165710
Ref: tutorial/datastructures tut-lists-as-queues6165842
Ref: 1ddc6165842
Ref: tutorial/datastructures using-lists-as-queues6165842
Ref: 1ddd6165842
Node: List Comprehensions<2>6166906
Ref: tutorial/datastructures list-comprehensions6167043
Ref: 1dde6167043
Ref: tutorial/datastructures tut-listcomps6167043
Ref: 1ddf6167043
Node: Nested List Comprehensions6170284
Ref: tutorial/datastructures nested-list-comprehensions6170391
Ref: 1de06170391
Node: The del statement6172049
Ref: tutorial/datastructures the-del-statement6172169
Ref: 1de16172169
Ref: tutorial/datastructures tut-del6172169
Ref: 1de26172169
Node: Tuples and Sequences6173028
Ref: tutorial/datastructures tuples-and-sequences6173139
Ref: 1de36173139
Ref: tutorial/datastructures tut-tuples6173139
Ref: 1dbe6173139
Node: Sets6176172
Ref: tutorial/datastructures sets6176278
Ref: 1de56176278
Ref: tutorial/datastructures tut-sets6176278
Ref: 1de66176278
Node: Dictionaries6178158
Ref: tutorial/datastructures dictionaries6178262
Ref: 1de86178262
Ref: tutorial/datastructures tut-dictionaries6178262
Ref: 1de96178262
Node: Looping Techniques6181518
Ref: tutorial/datastructures looping-techniques6181636
Ref: 1deb6181636
Ref: tutorial/datastructures tut-loopidioms6181636
Ref: 1da76181636
Node: More on Conditions6184264
Ref: tutorial/datastructures more-on-conditions6184405
Ref: 1dec6184405
Ref: tutorial/datastructures tut-conditions6184405
Ref: 1ded6184405
Node: Comparing Sequences and Other Types6186480
Ref: tutorial/datastructures comparing-sequences-and-other-types6186594
Ref: 1def6186594
Ref: tutorial/datastructures tut-comparing6186594
Ref: 1df06186594
Node: Modules<2>6188181
Ref: tutorial/modules doc6188296
Ref: 1df16188296
Ref: tutorial/modules modules6188296
Ref: 1df26188296
Ref: tutorial/modules translation-repo6188296
Ref: 1df36188296
Ref: tutorial/modules tut-modules6188296
Ref: 1df46188296
Node: More on Modules6190943
Ref: tutorial/modules more-on-modules6191030
Ref: 1df76191030
Ref: tutorial/modules tut-moremodules6191030
Ref: 1df86191030
Ref: More on Modules-Footnote-16194199
Node: Executing modules as scripts6194398
Ref: tutorial/modules executing-modules-as-scripts6194509
Ref: 1df96194509
Ref: tutorial/modules tut-modulesasscripts6194509
Ref: 1dfa6194509
Node: The Module Search Path6195397
Ref: tutorial/modules the-module-search-path6195544
Ref: 1dfb6195544
Ref: tutorial/modules tut-searchpath6195544
Ref: 1dfc6195544
Node: “Compiled” Python files6197123
Ref: tutorial/modules compiled-python-files6197233
Ref: 1e006197233
Ref: tutorial/modules tut-pycache6197233
Ref: 6df6197233
Ref: “Compiled” Python files-Footnote-16199542
Node: Standard Modules6199584
Ref: tutorial/modules standard-modules6199696
Ref: 1e016199696
Ref: tutorial/modules tut-standardmodules6199696
Ref: 1dff6199696
Node: The dir Function6201155
Ref: tutorial/modules the-dir-function6201260
Ref: 1e026201260
Ref: tutorial/modules tut-dir6201260
Ref: 1e036201260
Node: Packages6205783
Ref: tutorial/modules packages6205863
Ref: 1e046205863
Ref: tutorial/modules tut-packages6205863
Ref: 1e056205863
Node: Importing * From a Package6210249
Ref: tutorial/modules importing-from-a-package6210353
Ref: 1e076210353
Ref: tutorial/modules tut-pkg-import-star6210353
Ref: 1e086210353
Node: Intra-package References6213755
Ref: tutorial/modules id26213900
Ref: 1e096213900
Ref: tutorial/modules intra-package-references6213900
Ref: 1e0a6213900
Node: Packages in Multiple Directories6214911
Ref: tutorial/modules packages-in-multiple-directories6215021
Ref: 1e0b6215021
Node: Input and Output6215578
Ref: tutorial/inputoutput doc6215699
Ref: 1e0d6215699
Ref: tutorial/inputoutput input-and-output6215699
Ref: 1e0e6215699
Ref: tutorial/inputoutput translation-repo6215699
Ref: 1e0f6215699
Ref: tutorial/inputoutput tut-io6215699
Ref: 1e106215699
Node: Fancier Output Formatting6216008
Ref: tutorial/inputoutput fancier-output-formatting6216120
Ref: 1e116216120
Ref: tutorial/inputoutput tut-formatting6216120
Ref: 1e126216120
Node: Formatted String Literals6220228
Ref: tutorial/inputoutput formatted-string-literals6220348
Ref: 1e156220348
Ref: tutorial/inputoutput tut-f-strings6220348
Ref: 1e146220348
Node: The String format Method6222351
Ref: tutorial/inputoutput the-string-format-method6222504
Ref: 1e166222504
Ref: tutorial/inputoutput tut-string-format6222504
Ref: 1e176222504
Node: Manual String Formatting6225435
Ref: tutorial/inputoutput manual-string-formatting6225584
Ref: 1e186225584
Node: Old string formatting6227113
Ref: tutorial/inputoutput old-string-formatting6227229
Ref: 1e1c6227229
Node: Reading and Writing Files6227810
Ref: tutorial/inputoutput reading-and-writing-files6227922
Ref: 1e1d6227922
Ref: tutorial/inputoutput tut-files6227922
Ref: 1e1e6227922
Node: Methods of File Objects6231174
Ref: tutorial/inputoutput methods-of-file-objects6231300
Ref: 1e1f6231300
Ref: tutorial/inputoutput tut-filemethods6231300
Ref: 1e206231300
Node: Saving structured data with json6235008
Ref: tutorial/inputoutput saving-structured-data-with-json6235134
Ref: 1e226235134
Ref: tutorial/inputoutput tut-json6235134
Ref: 1e236235134
Ref: Saving structured data with json-Footnote-16237988
Node: Errors and Exceptions6238013
Ref: tutorial/errors doc6238131
Ref: 1e276238131
Ref: tutorial/errors errors-and-exceptions6238131
Ref: 1e286238131
Ref: tutorial/errors translation-repo6238131
Ref: 1e296238131
Ref: tutorial/errors tut-errors6238131
Ref: 1e2a6238131
Node: Syntax Errors6238701
Ref: tutorial/errors syntax-errors6238791
Ref: 1e2b6238791
Ref: tutorial/errors tut-syntaxerrors6238791
Ref: 1e2c6238791
Node: Exceptions6239587
Ref: tutorial/errors exceptions6239705
Ref: 1e2d6239705
Ref: tutorial/errors tut-exceptions6239705
Ref: 1e2e6239705
Node: Handling Exceptions6241649
Ref: tutorial/errors handling-exceptions6241772
Ref: 1e2f6241772
Ref: tutorial/errors tut-handling6241772
Ref: 1dae6241772
Node: Raising Exceptions6248234
Ref: tutorial/errors raising-exceptions6248365
Ref: 1e306248365
Ref: tutorial/errors tut-raising6248365
Ref: 1e316248365
Node: Exception Chaining6249638
Ref: tutorial/errors exception-chaining6249773
Ref: 1e326249773
Ref: tutorial/errors tut-exception-chaining6249773
Ref: 1e336249773
Node: User-defined Exceptions6252001
Ref: tutorial/errors tut-userexceptions6252143
Ref: 1e346252143
Ref: tutorial/errors user-defined-exceptions6252143
Ref: 1e356252143
Node: Defining Clean-up Actions6252903
Ref: tutorial/errors defining-clean-up-actions6253054
Ref: 1e366253054
Ref: tutorial/errors tut-cleanup6253054
Ref: 1e376253054
Node: Predefined Clean-up Actions6256471
Ref: tutorial/errors predefined-clean-up-actions6256649
Ref: 1e386256649
Ref: tutorial/errors tut-cleanup-with6256649
Ref: 1e396256649
Node: Raising and Handling Multiple Unrelated Exceptions6257768
Ref: tutorial/errors raising-and-handling-multiple-unrelated-exceptions6257952
Ref: 1e3a6257952
Ref: tutorial/errors tut-exception-groups6257952
Ref: 1e3b6257952
Node: Enriching Exceptions with Notes6261580
Ref: tutorial/errors enriching-exceptions-with-notes6261728
Ref: 1e3c6261728
Ref: tutorial/errors tut-exception-notes6261728
Ref: 1e3d6261728
Node: Classes6264607
Ref: tutorial/classes doc6264743
Ref: 1e3e6264743
Ref: tutorial/classes classes6264743
Ref: 1e3f6264743
Ref: tutorial/classes translation-repo6264743
Ref: 1e406264743
Ref: tutorial/classes tut-classes6264743
Ref: 1db76264743
Node: A Word About Names and Objects6267057
Ref: tutorial/classes a-word-about-names-and-objects6267168
Ref: 1e426267168
Ref: tutorial/classes tut-object6267168
Ref: 1e436267168
Node: Python Scopes and Namespaces6268090
Ref: tutorial/classes python-scopes-and-namespaces6268233
Ref: 1e446268233
Ref: tutorial/classes tut-scopes6268233
Ref: 1df66268233
Ref: Python Scopes and Namespaces-Footnote-16274325
Node: Scopes and Namespaces Example6274709
Ref: tutorial/classes scopes-and-namespaces-example6274803
Ref: 1e466274803
Ref: tutorial/classes tut-scopeexample6274803
Ref: 1e476274803
Node: A First Look at Classes6276161
Ref: tutorial/classes a-first-look-at-classes6276288
Ref: 1e486276288
Ref: tutorial/classes tut-firstclasses6276288
Ref: 1dd26276288
Node: Class Definition Syntax6276573
Ref: tutorial/classes class-definition-syntax6276678
Ref: 1e496276678
Ref: tutorial/classes tut-classdefinition6276678
Ref: 1e4a6276678
Node: Class Objects6278215
Ref: tutorial/classes class-objects6278345
Ref: 1e4b6278345
Ref: tutorial/classes tut-classobjects6278345
Ref: 1e4c6278345
Node: Instance Objects6280542
Ref: tutorial/classes instance-objects6280663
Ref: 1e4e6280663
Ref: tutorial/classes tut-instanceobjects6280663
Ref: 1e4f6280663
Node: Method Objects6281972
Ref: tutorial/classes method-objects6282108
Ref: 1e506282108
Ref: tutorial/classes tut-methodobjects6282108
Ref: 1e516282108
Node: Class and Instance Variables6283913
Ref: tutorial/classes class-and-instance-variables6284024
Ref: 1e526284024
Ref: tutorial/classes tut-class-and-instance-variables6284024
Ref: 1e536284024
Node: Random Remarks6286063
Ref: tutorial/classes random-remarks6286173
Ref: 1e546286173
Ref: tutorial/classes tut-remarks6286173
Ref: 1e556286173
Node: Inheritance6290006
Ref: tutorial/classes inheritance6290110
Ref: 1e566290110
Ref: tutorial/classes tut-inheritance6290110
Ref: 1e576290110
Node: Multiple Inheritance6292894
Ref: tutorial/classes multiple-inheritance6292962
Ref: 1e586292962
Ref: tutorial/classes tut-multiple6292962
Ref: 1e596292962
Node: Private Variables6294952
Ref: tutorial/classes private-variables6295055
Ref: 1e5a6295055
Ref: tutorial/classes tut-private6295055
Ref: 1e416295055
Node: Odds and Ends6297848
Ref: tutorial/classes odds-and-ends6297949
Ref: 1e5c6297949
Ref: tutorial/classes tut-odds6297949
Ref: 1e5d6297949
Node: Iterators6299085
Ref: tutorial/classes iterators6299179
Ref: 1e606299179
Ref: tutorial/classes tut-iterators6299179
Ref: 1e616299179
Node: Generators6301452
Ref: tutorial/classes generators6301554
Ref: 1e636301554
Ref: tutorial/classes tut-generators6301554
Ref: 1e646301554
Node: Generator Expressions6302994
Ref: tutorial/classes generator-expressions6303078
Ref: 1e676303078
Ref: tutorial/classes tut-genexps6303078
Ref: 1e686303078
Node: Brief tour of the standard library6304065
Ref: tutorial/stdlib doc6304226
Ref: 1e696304226
Ref: tutorial/stdlib brief-tour-of-the-standard-library6304226
Ref: 1e6a6304226
Ref: tutorial/stdlib translation-repo6304226
Ref: 1e6b6304226
Ref: tutorial/stdlib tut-brieftour6304226
Ref: 1e6c6304226
Node: Operating system interface6304623
Ref: tutorial/stdlib operating-system-interface6304743
Ref: 1e6d6304743
Ref: tutorial/stdlib tut-os-interface6304743
Ref: 1e6e6304743
Node: File wildcards6306009
Ref: tutorial/stdlib file-wildcards6306160
Ref: 1e6f6306160
Ref: tutorial/stdlib tut-file-wildcards6306160
Ref: 1e706306160
Node: Command-line arguments6306402
Ref: tutorial/stdlib command-line-arguments6306575
Ref: 1e716306575
Ref: tutorial/stdlib tut-command-line-arguments6306575
Ref: 1e726306575
Node: Error output redirection and program termination6307741
Ref: tutorial/stdlib error-output-redirection-and-program-termination6307923
Ref: 1e736307923
Ref: tutorial/stdlib tut-stderr6307923
Ref: 1e746307923
Node: String pattern matching6308446
Ref: tutorial/stdlib string-pattern-matching6308617
Ref: 1e756308617
Ref: tutorial/stdlib tut-string-pattern-matching6308617
Ref: 1e766308617
Node: Mathematics6309256
Ref: tutorial/stdlib mathematics6309394
Ref: 1e776309394
Ref: tutorial/stdlib tut-mathematics6309394
Ref: 1e786309394
Node: Internet access6310571
Ref: tutorial/stdlib internet-access6310701
Ref: 1e796310701
Ref: tutorial/stdlib tut-internet-access6310701
Ref: 1e7a6310701
Node: Dates and times6311732
Ref: tutorial/stdlib dates-and-times6311867
Ref: 1e7b6311867
Ref: tutorial/stdlib tut-dates-and-times6311867
Ref: 1e7c6311867
Node: Data compression6312690
Ref: tutorial/stdlib data-compression6312833
Ref: 1e7d6312833
Ref: tutorial/stdlib tut-data-compression6312833
Ref: 1e7e6312833
Node: Performance measurement6313355
Ref: tutorial/stdlib performance-measurement6313498
Ref: 1e7f6313498
Ref: tutorial/stdlib tut-performance-measurement6313498
Ref: 1e806313498
Node: Quality control6314371
Ref: tutorial/stdlib quality-control6314516
Ref: 1e816314516
Ref: tutorial/stdlib tut-quality-control6314516
Ref: 1e826314516
Node: Batteries included6316084
Ref: tutorial/stdlib batteries-included6316197
Ref: 1e836316197
Ref: tutorial/stdlib tut-batteries-included6316197
Ref: 1e846316197
Ref: Batteries included-Footnote-16318012
Node: Brief Tour of the Standard Library — Part II6318071
Ref: tutorial/stdlib2 doc6318258
Ref: 1e856318258
Ref: tutorial/stdlib2 brief-tour-of-the-standard-library-part-ii6318258
Ref: 1e866318258
Ref: tutorial/stdlib2 translation-repo6318258
Ref: 1e876318258
Ref: tutorial/stdlib2 tut-brieftourtwo6318258
Ref: 1e886318258
Node: Output Formatting6318732
Ref: tutorial/stdlib2 output-formatting6318851
Ref: 1e896318851
Ref: tutorial/stdlib2 tut-output-formatting6318851
Ref: 1e8a6318851
Node: Templating6320970
Ref: tutorial/stdlib2 templating6321137
Ref: 1e8b6321137
Ref: tutorial/stdlib2 tut-templating6321137
Ref: 1e8c6321137
Node: Working with Binary Data Record Layouts6323701
Ref: tutorial/stdlib2 tut-binary-formats6323869
Ref: 1e8f6323869
Ref: tutorial/stdlib2 working-with-binary-data-record-layouts6323869
Ref: 1e906323869
Node: Multi-threading<2>6325045
Ref: tutorial/stdlib2 multi-threading6325210
Ref: 1e916325210
Ref: tutorial/stdlib2 tut-multi-threading6325210
Ref: 1e926325210
Node: Logging6327153
Ref: tutorial/stdlib2 logging6327294
Ref: 1e936327294
Ref: tutorial/stdlib2 tut-logging6327294
Ref: 1e946327294
Node: Weak References6328492
Ref: tutorial/stdlib2 tut-weak-references6328643
Ref: 1e9a6328643
Ref: tutorial/stdlib2 weak-references6328643
Ref: 1e9b6328643
Node: Tools for Working with Lists6330401
Ref: tutorial/stdlib2 tools-for-working-with-lists6330578
Ref: 1e9c6330578
Ref: tutorial/stdlib2 tut-list-tools6330578
Ref: 1e9d6330578
Node: Decimal Floating-Point Arithmetic6333028
Ref: tutorial/stdlib2 decimal-floating-point-arithmetic6333181
Ref: 1e9e6333181
Ref: tutorial/stdlib2 tut-decimal-fp6333181
Ref: 1e9f6333181
Node: Virtual Environments and Packages6335122
Ref: tutorial/venv doc6335284
Ref: 1ea06335284
Ref: tutorial/venv translation-repo6335284
Ref: 1ea16335284
Ref: tutorial/venv tut-venv6335284
Ref: 1ea26335284
Ref: tutorial/venv virtual-environments-and-packages6335284
Ref: 1ea36335284
Node: Introduction<4>6335471
Ref: tutorial/venv introduction6335594
Ref: 1ea46335594
Node: Creating Virtual Environments6336916
Ref: tutorial/venv creating-virtual-environments6337074
Ref: 1ea66337074
Node: Managing Packages with pip6339149
Ref: tutorial/venv managing-packages-with-pip6339283
Ref: 1ea76339283
Ref: Managing Packages with pip-Footnote-16343255
Ref: Managing Packages with pip-Footnote-26343280
Node: What Now?6343358
Ref: tutorial/whatnow doc6343524
Ref: 1ea86343524
Ref: tutorial/whatnow translation-repo6343524
Ref: 1ea96343524
Ref: tutorial/whatnow tut-whatnow6343524
Ref: 1eaa6343524
Ref: tutorial/whatnow what-now6343524
Ref: 1eab6343524
Ref: What Now?-Footnote-16346769
Node: Interactive Input Editing and History Substitution6346918
Ref: tutorial/interactive doc6347099
Ref: 1ead6347099
Ref: tutorial/interactive interactive-input-editing-and-history-substitution6347099
Ref: 1eae6347099
Ref: tutorial/interactive translation-repo6347099
Ref: 1eaf6347099
Ref: tutorial/interactive tut-interacting6347099
Ref: 1d7c6347099
Ref: Interactive Input Editing and History Substitution-Footnote-16347695
Node: Tab Completion and History Editing6347756
Ref: tutorial/interactive tab-completion-and-history-editing6347929
Ref: 1eb06347929
Ref: tutorial/interactive tut-keybindings6347929
Ref: 1eb16347929
Node: Alternatives to the Interactive Interpreter6348786
Ref: tutorial/interactive alternatives-to-the-interactive-interpreter6348959
Ref: 1eb26348959
Ref: tutorial/interactive tut-commentary6348959
Ref: 1eb36348959
Ref: Alternatives to the Interactive Interpreter-Footnote-16349866
Ref: Alternatives to the Interactive Interpreter-Footnote-26349895
Node: Floating-Point Arithmetic Issues and Limitations6349936
Ref: tutorial/floatingpoint doc6350116
Ref: 1eb56350116
Ref: tutorial/floatingpoint floating-point-arithmetic-issues-and-limitations6350116
Ref: 1eb66350116
Ref: tutorial/floatingpoint translation-repo6350116
Ref: 1eb76350116
Ref: tutorial/floatingpoint tut-fp-issues6350116
Ref: 1eb86350116
Ref: Floating-Point Arithmetic Issues and Limitations-Footnote-16359610
Ref: Floating-Point Arithmetic Issues and Limitations-Footnote-26359688
Node: Representation Error6359739
Ref: tutorial/floatingpoint representation-error6359844
Ref: 1ebb6359844
Ref: tutorial/floatingpoint tut-fp-error6359844
Ref: 1ebc6359844
Node: Appendix6363095
Ref: tutorial/appendix doc6363216
Ref: 1ebd6363216
Ref: tutorial/appendix appendix6363216
Ref: 1ebe6363216
Ref: tutorial/appendix translation-repo6363216
Ref: 1ebf6363216
Ref: tutorial/appendix tut-appendix6363216
Ref: 1ec06363216
Node: Interactive Mode<2>6363296
Ref: tutorial/appendix interactive-mode6363360
Ref: 1ec16363360
Ref: tutorial/appendix tut-interac6363360
Ref: 16f6363360
Node: Error Handling6364618
Ref: tutorial/appendix error-handling6364722
Ref: 1ec26364722
Ref: tutorial/appendix tut-error6364722
Ref: 1ec36364722
Ref: Error Handling-Footnote-16365789
Node: Executable Python Scripts6365855
Ref: tutorial/appendix executable-python-scripts6365996
Ref: 1ec46365996
Ref: tutorial/appendix tut-scripts6365996
Ref: 1d846365996
Node: The Interactive Startup File6367076
Ref: tutorial/appendix the-interactive-startup-file6367228
Ref: 1ec56367228
Ref: tutorial/appendix tut-startup6367228
Ref: 1ec66367228
Node: The Customization Modules6368665
Ref: tutorial/appendix the-customization-modules6368783
Ref: 1ec76368783
Ref: tutorial/appendix tut-customize6368783
Ref: 1ec86368783
Node: Python Setup and Usage6369663
Ref: using/index doc6369791
Ref: 1ec96369791
Ref: using/index python-setup-and-usage6369791
Ref: 1eca6369791
Ref: using/index translation-repo6369791
Ref: 1ecb6369791
Ref: using/index using-index6369791
Ref: 1ecc6369791
Node: Command line and environment6370280
Ref: using/cmdline doc6370406
Ref: 1ecd6370406
Ref: using/cmdline command-line-and-environment6370406
Ref: 1ece6370406
Ref: using/cmdline using-on-general6370406
Ref: 1b4f6370406
Node: Command line6370775
Ref: using/cmdline command-line6370882
Ref: 1ed06370882
Ref: using/cmdline using-on-cmdline6370882
Ref: 10426370882
Node: Interface options6371300
Ref: using/cmdline interface-options6371390
Ref: 1ed16371390
Ref: using/cmdline using-on-interface-options6371390
Ref: 1ed26371390
Ref: using/cmdline cmdoption-c6372860
Ref: 5e36372860
Ref: using/cmdline cmdoption-m6373429
Ref: 5e46373429
Ref: using/cmdline cmdarg-dash6375819
Ref: 1ed36375819
Ref: using/cmdline cmdarg-script6376239
Ref: 1ed46376239
Ref: Interface options-Footnote-16378093
Node: Generic options6378135
Ref: using/cmdline generic-options6378255
Ref: 1ed56378255
Ref: using/cmdline using-on-generic-options6378255
Ref: 1ed66378255
Ref: using/cmdline cmdoption-06378304
Ref: 14766378304
Ref: using/cmdline cmdoption-h6378319
Ref: 1ed76378319
Ref: using/cmdline cmdoption-help6378334
Ref: 5f36378334
Ref: using/cmdline cmdoption-help-env6378469
Ref: 5f56378469
Ref: using/cmdline cmdoption-help-xoptions6378610
Ref: 5f66378610
Ref: using/cmdline cmdoption-help-all6378759
Ref: 5f76378759
Ref: using/cmdline cmdoption-V6378861
Ref: 1776378861
Ref: using/cmdline cmdoption-version6378876
Ref: d436378876
Node: Miscellaneous options6379218
Ref: using/cmdline miscellaneous-options6379338
Ref: 1ed86379338
Ref: using/cmdline using-on-misc-options6379338
Ref: 10436379338
Ref: using/cmdline cmdoption-b6379399
Ref: 5e66379399
Ref: using/cmdline cmdoption-B6379815
Ref: 141b6379815
Ref: using/cmdline cmdoption-check-hash-based-pycs6379977
Ref: 1ed96379977
Ref: using/cmdline cmdoption-d6380671
Ref: 1eda6380671
Ref: using/cmdline cmdoption-E6380904
Ref: 9676380904
Ref: using/cmdline cmdoption-i6381128
Ref: 152a6381128
Ref: using/cmdline cmdoption-I6381766
Ref: 9686381766
Ref: using/cmdline cmdoption-O6382218
Ref: de36382218
Ref: using/cmdline cmdoption-OO6382606
Ref: de46382606
Ref: using/cmdline cmdoption-P6382911
Ref: 5a76382911
Ref: using/cmdline cmdoption-q6383584
Ref: 15c96383584
Ref: using/cmdline cmdoption-R6383716
Ref: 1c296383716
Ref: using/cmdline cmdoption-s6384803
Ref: 13db6384803
Ref: using/cmdline cmdoption-S6385040
Ref: 11ec6385040
Ref: using/cmdline cmdoption-u6385352
Ref: 1b366385352
Ref: using/cmdline cmdoption-v6385628
Ref: 14736385628
Ref: using/cmdline using-on-warnings6386133
Ref: 1ee06386133
Ref: using/cmdline cmdoption-W6386133
Ref: 8d06386133
Ref: using/cmdline cmdoption-x6388639
Ref: 1ee26388639
Ref: using/cmdline cmdoption-X6388796
Ref: 1766388796
Ref: Miscellaneous options-Footnote-16395384
Ref: Miscellaneous options-Footnote-26395426
Ref: Miscellaneous options-Footnote-36395468
Ref: Miscellaneous options-Footnote-46395510
Ref: Miscellaneous options-Footnote-56395552
Node: Controlling color6395594
Ref: using/cmdline controlling-color6395726
Ref: 1ee86395726
Ref: using/cmdline using-on-controlling-color6395726
Ref: 16b6395726
Ref: Controlling color-Footnote-16396784
Ref: Controlling color-Footnote-26396817
Node: Options you shouldn’t use6396847
Ref: using/cmdline no-color6396949
Ref: 1ee96396949
Ref: using/cmdline options-you-shouldn-t-use6396949
Ref: 1eea6396949
Ref: using/cmdline cmdoption-J6397020
Ref: 141a6397020
Ref: Options you shouldn’t use-Footnote-16397109
Node: Environment variables6397141
Ref: using/cmdline environment-variables6397248
Ref: 1eeb6397248
Ref: using/cmdline using-on-envvars6397248
Ref: 5f46397248
Ref: using/cmdline envvar-PYTHONHOME6397541
Ref: 3bf6397541
Ref: using/cmdline envvar-PYTHONPATH6398136
Ref: 10586398136
Ref: using/cmdline envvar-PYTHONSAFEPATH6399202
Ref: 5a86399202
Ref: using/cmdline envvar-PYTHONPLATLIBDIR6399437
Ref: 1aca6399437
Ref: using/cmdline envvar-PYTHONSTARTUP6399609
Ref: 10036399609
Ref: using/cmdline envvar-PYTHONOPTIMIZE6400299
Ref: 1edc6400299
Ref: using/cmdline envvar-PYTHONBREAKPOINT6400531
Ref: af16400531
Ref: using/cmdline envvar-PYTHONDEBUG6401150
Ref: 1edb6401150
Ref: using/cmdline envvar-PYTHONINSPECT6401488
Ref: 15296401488
Ref: using/cmdline envvar-PYTHONUNBUFFERED6402108
Ref: 1b376402108
Ref: using/cmdline envvar-PYTHONVERBOSE6402259
Ref: 1edf6402259
Ref: using/cmdline envvar-PYTHONCASEOK6402491
Ref: 9666402491
Ref: using/cmdline envvar-PYTHONDONTWRITEBYTECODE6402651
Ref: 141c6402651
Ref: using/cmdline envvar-PYTHONPYCACHEPREFIX6402896
Ref: 9ae6402896
Ref: using/cmdline envvar-PYTHONHASHSEED6403239
Ref: 10bb6403239
Ref: using/cmdline envvar-PYTHONINTMAXSTRDIGITS6403925
Ref: 18dd6403925
Ref: using/cmdline envvar-PYTHONIOENCODING6404165
Ref: 10456404165
Ref: using/cmdline envvar-PYTHONNOUSERSITE6404988
Ref: 13dc6404988
Ref: using/cmdline envvar-PYTHONUSERBASE6405231
Ref: 13da6405231
Ref: using/cmdline envvar-PYTHONEXECUTABLE6405581
Ref: 1ef06405581
Ref: using/cmdline envvar-PYTHONWARNINGS6405791
Ref: bc86405791
Ref: using/cmdline envvar-PYTHONFAULTHANDLER6406773
Ref: 10c36406773
Ref: using/cmdline envvar-PYTHONTRACEMALLOC6407224
Ref: 1ee46407224
Ref: using/cmdline envvar-PYTHONPROFILEIMPORTTIME6407794
Ref: b0e6407794
Ref: using/cmdline envvar-PYTHONASYNCIODEBUG6408068
Ref: 1ef16408068
Ref: using/cmdline envvar-PYTHONMALLOC6408280
Ref: c856408280
Ref: using/cmdline envvar-PYTHONMALLOCSTATS6409740
Ref: 1ce86409740
Ref: using/cmdline envvar-PYTHONLEGACYWINDOWSFSENCODING6410355
Ref: 2af6410355
Ref: using/cmdline envvar-PYTHONLEGACYWINDOWSSTDIO6410892
Ref: c7c6410892
Ref: using/cmdline envvar-PYTHONCOERCECLOCALE6411365
Ref: aeb6411365
Ref: using/cmdline envvar-PYTHONDEVMODE6414095
Ref: b066414095
Ref: using/cmdline envvar-PYTHONUTF86414442
Ref: aee6414442
Ref: using/cmdline envvar-PYTHONWARNDEFAULTENCODING6414738
Ref: 7c06414738
Ref: using/cmdline envvar-PYTHONNODEBUGRANGES6415042
Ref: 5b96415042
Ref: using/cmdline envvar-PYTHONPERFSUPPORT6415511
Ref: 4716415511
Ref: using/cmdline envvar-PYTHON_PERF_JIT_SUPPORT6415923
Ref: 1906415923
Ref: using/cmdline envvar-PYTHON_CPU_COUNT6416374
Ref: 2106416374
Ref: using/cmdline envvar-PYTHON_FROZEN_MODULES6416675
Ref: 18e6416675
Ref: using/cmdline envvar-PYTHON_COLORS6417320
Ref: 14a6417320
Ref: using/cmdline envvar-PYTHON_BASIC_REPL6417587
Ref: 16e6417587
Ref: using/cmdline envvar-PYTHON_HISTORY6417907
Ref: 1916417907
Ref: using/cmdline envvar-PYTHON_GIL6418158
Ref: 1756418158
Ref: using/cmdline envvar-PYTHON_JIT6418596
Ref: 17b6418596
Ref: Environment variables-Footnote-16418920
Ref: Environment variables-Footnote-26418962
Ref: Environment variables-Footnote-36419004
Ref: Environment variables-Footnote-46419046
Node: Debug-mode variables6419088
Ref: using/cmdline debug-mode-variables6419166
Ref: 1ef96419166
Ref: using/cmdline envvar-PYTHONDUMPREFS6419225
Ref: 9b16419225
Ref: using/cmdline envvar-PYTHONDUMPREFSFILE6419468
Ref: 19e56419468
Ref: using/cmdline envvar-PYTHON_PRESITE6419824
Ref: 1ee66419824
Node: Using Python on Unix platforms6420566
Ref: using/unix doc6420717
Ref: 1efa6420717
Ref: using/unix translation-repo6420717
Ref: 1efb6420717
Ref: using/unix using-on-unix6420717
Ref: 1efc6420717
Ref: using/unix using-python-on-unix-platforms6420717
Ref: 1efd6420717
Node: Getting and installing the latest version of Python6420946
Ref: using/unix getting-and-installing-the-latest-version-of-python6421088
Ref: 1efe6421088
Node: On Linux6421255
Ref: using/unix on-linux6421382
Ref: 1eff6421382
Node: Installing IDLE6422313
Ref: using/unix installing-idle6422373
Ref: 1f006422373
Ref: using/unix installing-idle-on-linux6422373
Ref: 1f016422373
Node: On FreeBSD and OpenBSD6422817
Ref: using/unix on-freebsd-and-openbsd6422944
Ref: 1f026422944
Node: Building Python6423434
Ref: using/unix building-python6423615
Ref: 1f036423615
Ref: using/unix building-python-on-unix6423615
Ref: f2a6423615
Ref: Building Python-Footnote-16424443
Ref: Building Python-Footnote-26424492
Ref: Building Python-Footnote-36424555
Node: Python-related paths and files6424618
Ref: using/unix python-related-paths-and-files6424761
Ref: 1f056424761
Node: Miscellaneous6426304
Ref: using/unix miscellaneous6426446
Ref: 1f086426446
Node: Custom OpenSSL6427004
Ref: using/unix custom-openssl6427107
Ref: 1f096427107
Ref: using/unix unix-custom-openssl6427107
Ref: 1f0a6427107
Node: Configure Python6428727
Ref: using/configure doc6428873
Ref: 1f0b6428873
Ref: using/configure configure-python6428873
Ref: 1f0c6428873
Ref: using/configure translation-repo6428873
Ref: 1f0d6428873
Node: Build Requirements6429045
Ref: using/configure build-requirements6429140
Ref: 1f0e6429140
Ref: Build Requirements-Footnote-16430858
Ref: Build Requirements-Footnote-26430901
Ref: Build Requirements-Footnote-36430984
Ref: Build Requirements-Footnote-46431031
Ref: Build Requirements-Footnote-56431088
Ref: Build Requirements-Footnote-66431145
Ref: Build Requirements-Footnote-76431187
Node: Generated files6431229
Ref: using/configure generated-files6431350
Ref: 1f0f6431350
Node: configure script6431815
Ref: using/configure configure-script6431883
Ref: 1f106431883
Node: Configure Options6432421
Ref: using/configure configure-options6432543
Ref: 1f046432543
Ref: using/configure id16432543
Ref: 1f116432543
Node: General Options6433107
Ref: using/configure general-options6433203
Ref: 1f126433203
Ref: using/configure cmdoption-enable-loadable-sqlite-extensions6433252
Ref: 1f136433252
Ref: using/configure cmdoption-disable-ipv66433571
Ref: 1f146433571
Ref: using/configure cmdoption-enable-big-digits6433700
Ref: 7506433700
Ref: using/configure cmdoption-with-suffix6433985
Ref: 1f156433985
Ref: using/configure cmdoption-with-tzpath6434450
Ref: 1f166434450
Ref: using/configure cmdoption-without-decimal-contextvar6434879
Ref: 1f196434879
Ref: using/configure cmdoption-with-dbmliborder6435211
Ref: 1f1b6435211
Ref: using/configure cmdoption-without-c-locale-coercion6435494
Ref: 1f1c6435494
Ref: using/configure cmdoption-without-freelists6435737
Ref: 74f6435737
Ref: using/configure cmdoption-with-platlibdir6435861
Ref: 1f1d6435861
Ref: using/configure cmdoption-with-wheel-pkg-dir6436084
Ref: 8946436084
Ref: using/configure cmdoption-with-pkg-config6436507
Ref: 1f1e6436507
Ref: using/configure cmdoption-enable-pystats6436863
Ref: 18db6436863
Ref: using/configure free-threading-build6439176
Ref: 1f1f6439176
Ref: using/configure cmdoption-disable-gil6439176
Ref: 1746439176
Ref: using/configure cmdoption-enable-experimental-jit6439529
Ref: 1f206439529
Ref: using/configure cmdoption-arg-PKG_CONFIG6440268
Ref: 1f216440268
Ref: using/configure cmdoption-arg-PKG_CONFIG_LIBDIR6440332
Ref: 1f226440332
Ref: using/configure cmdoption-arg-PKG_CONFIG_PATH6440363
Ref: 1f236440363
Ref: General Options-Footnote-16440460
Node: C compiler options6440502
Ref: using/configure c-compiler-options6440621
Ref: 1f246440621
Ref: using/configure cmdoption-arg-CC6440676
Ref: 1f256440676
Ref: using/configure cmdoption-arg-CFLAGS6440718
Ref: 1f266440718
Ref: using/configure cmdoption-arg-CPP6440762
Ref: 1f276440762
Ref: using/configure cmdoption-arg-CPPFLAGS6440809
Ref: 1f286440809
Node: Linker options6440886
Ref: using/configure linker-options6441026
Ref: 1f296441026
Ref: using/configure cmdoption-arg-LDFLAGS6441073
Ref: 1f2a6441073
Ref: using/configure cmdoption-arg-LIBS6441147
Ref: 1f2b6441147
Ref: using/configure cmdoption-arg-MACHDEP6441227
Ref: 1f2c6441227
Node: Options for third-party dependencies6441296
Ref: using/configure options-for-third-party-dependencies6441437
Ref: 1f2d6441437
Ref: using/configure cmdoption-arg-BZIP2_CFLAGS6441552
Ref: 1f2e6441552
Ref: using/configure cmdoption-arg-BZIP2_LIBS6441578
Ref: 1f2f6441578
Ref: using/configure cmdoption-arg-CURSES_CFLAGS6441733
Ref: 1f306441733
Ref: using/configure cmdoption-arg-CURSES_LIBS6441760
Ref: 1f316441760
Ref: using/configure cmdoption-arg-GDBM_CFLAGS6441930
Ref: 1f326441930
Ref: using/configure cmdoption-arg-GDBM_LIBS6441955
Ref: 1f336441955
Ref: using/configure cmdoption-arg-LIBB2_CFLAGS6442028
Ref: 1f346442028
Ref: using/configure cmdoption-arg-LIBB2_LIBS6442054
Ref: 1f356442054
Ref: using/configure cmdoption-arg-LIBEDIT_CFLAGS6442220
Ref: 1f376442220
Ref: using/configure cmdoption-arg-LIBEDIT_LIBS6442248
Ref: 1f386442248
Ref: using/configure cmdoption-arg-LIBFFI_CFLAGS6442397
Ref: 1f396442397
Ref: using/configure cmdoption-arg-LIBFFI_LIBS6442424
Ref: 1f3a6442424
Ref: using/configure cmdoption-arg-LIBMPDEC_CFLAGS6442569
Ref: 1f3b6442569
Ref: using/configure cmdoption-arg-LIBMPDEC_LIBS6442598
Ref: 1f3c6442598
Ref: using/configure cmdoption-arg-LIBLZMA_CFLAGS6442873
Ref: 1f3d6442873
Ref: using/configure cmdoption-arg-LIBLZMA_LIBS6442901
Ref: 1f3e6442901
Ref: using/configure cmdoption-arg-LIBREADLINE_CFLAGS6443046
Ref: 1f3f6443046
Ref: using/configure cmdoption-arg-LIBREADLINE_LIBS6443078
Ref: 1f406443078
Ref: using/configure cmdoption-arg-LIBSQLITE3_CFLAGS6443235
Ref: 1f416443235
Ref: using/configure cmdoption-arg-LIBSQLITE3_LIBS6443266
Ref: 1f426443266
Ref: using/configure cmdoption-arg-LIBUUID_CFLAGS6443420
Ref: 1f436443420
Ref: using/configure cmdoption-arg-LIBUUID_LIBS6443448
Ref: 1f446443448
Ref: using/configure cmdoption-arg-PANEL_CFLAGS6443594
Ref: 1f456443594
Ref: using/configure cmdoption-arg-PANEL_LIBS6443620
Ref: 1f466443620
Ref: using/configure cmdoption-arg-TCLTK_CFLAGS6443865
Ref: 1f476443865
Ref: using/configure cmdoption-arg-TCLTK_LIBS6443891
Ref: 1f486443891
Ref: using/configure cmdoption-arg-ZLIB_CFLAGS6443989
Ref: 1f496443989
Ref: using/configure cmdoption-arg-ZLIB_LIBS6444014
Ref: 1f4a6444014
Node: WebAssembly Options6444156
Ref: using/configure webassembly-options6444298
Ref: 1f4b6444298
Ref: using/configure cmdoption-with-emscripten-target6444355
Ref: 1f4c6444355
Ref: using/configure cmdoption-enable-wasm-dynamic-linking6444618
Ref: 19636444618
Ref: using/configure cmdoption-enable-wasm-pthreads6444893
Ref: 19336444893
Node: Install Options6444999
Ref: using/configure install-options6445124
Ref: 1f4d6445124
Ref: using/configure cmdoption-prefix6445173
Ref: 1f066445173
Ref: using/configure cmdoption-exec-prefix6445491
Ref: 1f076445491
Ref: using/configure cmdoption-disable-test-modules6445703
Ref: 8936445703
Ref: using/configure cmdoption-with-ensurepip6445931
Ref: 1f4e6445931
Node: Performance options6446314
Ref: using/configure performance-options6446438
Ref: 1f4f6446438
Ref: using/configure cmdoption-enable-optimizations6446694
Ref: 8686446694
Ref: using/configure envvar-PROFILE_TASK6447692
Ref: 181d6447692
Ref: using/configure cmdoption-with-lto6448014
Ref: 74e6448014
Ref: using/configure cmdoption-enable-bolt6448533
Ref: 1f506448533
Ref: using/configure cmdoption-arg-BOLT_APPLY_FLAGS6449600
Ref: 1f516449600
Ref: using/configure cmdoption-arg-BOLT_INSTRUMENT_FLAGS6449736
Ref: 1f526449736
Ref: using/configure cmdoption-with-computed-gotos6449864
Ref: 1f536449864
Ref: using/configure cmdoption-without-mimalloc6449996
Ref: 1f546449996
Ref: using/configure cmdoption-without-pymalloc6450172
Ref: 1f556450172
Ref: using/configure cmdoption-without-doc-strings6450368
Ref: 1f566450368
Ref: using/configure cmdoption-enable-profiling6450665
Ref: 1f576450665
Ref: using/configure cmdoption-with-strict-overflow6450773
Ref: 18766450773
Ref: Performance options-Footnote-16450964
Ref: Performance options-Footnote-26451024
Node: Python Debug Build6451072
Ref: using/configure debug-build6451194
Ref: 1f96451194
Ref: using/configure python-debug-build6451194
Ref: 1f586451194
Node: Debug options6453536
Ref: using/configure debug-options6453656
Ref: 1f596453656
Ref: using/configure cmdoption-with-pydebug6453701
Ref: 4276453701
Ref: using/configure cmdoption-with-trace-refs6453835
Ref: 3986453835
Ref: using/configure cmdoption-with-assertions6454477
Ref: 38f6454477
Ref: using/configure cmdoption-with-valgrind6454863
Ref: 1f5b6454863
Ref: using/configure cmdoption-with-dtrace6454939
Ref: 1f5c6454939
Ref: using/configure cmdoption-with-address-sanitizer6455109
Ref: 1f5d6455109
Ref: using/configure cmdoption-with-memory-sanitizer6455479
Ref: 1f5e6455479
Ref: using/configure cmdoption-with-undefined-behavior-sanitizer6455633
Ref: 1f5f6455633
Ref: using/configure cmdoption-with-thread-sanitizer6455814
Ref: 1f606455814
Node: Linker options<2>6455957
Ref: using/configure id26456076
Ref: 1f616456076
Ref: using/configure cmdoption-enable-shared6456125
Ref: 8696456125
Ref: using/configure cmdoption-without-static-libpython6456239
Ref: 8956456239
Node: Libraries options6456427
Ref: using/configure libraries-options6456549
Ref: 1f626456549
Ref: using/configure cmdoption-with-libs6456604
Ref: 1f636456604
Ref: using/configure cmdoption-with-system-expat6456697
Ref: 18d06456697
Ref: using/configure cmdoption-with-system-libmpdec6456828
Ref: 4156456828
Ref: using/configure cmdoption-with-readline6457407
Ref: 1f646457407
Ref: using/configure cmdoption-without-readline6457653
Ref: 1f656457653
Ref: using/configure cmdoption-with-libm6457840
Ref: 1f666457840
Ref: using/configure cmdoption-with-libc6457959
Ref: 1f676457959
Ref: using/configure cmdoption-with-openssl6458075
Ref: 1f686458075
Ref: using/configure cmdoption-with-openssl-rpath6458172
Ref: 8966458172
Node: Security Options6458512
Ref: using/configure security-options6458630
Ref: 1f696458630
Ref: using/configure cmdoption-with-hash-algorithm6458683
Ref: 1f6a6458683
Ref: using/configure cmdoption-with-builtin-hashlib-hashes6459008
Ref: 1f6b6459008
Ref: using/configure cmdoption-with-ssl-default-suites6459309
Ref: 1f6c6459309
Node: macOS Options6459791
Ref: using/configure macos-options6459903
Ref: 1f6d6459903
Ref: using/configure cmdoption-enable-universalsdk6459974
Ref: 9756459974
Ref: using/configure cmdoption-06460009
Ref: 1f6e6460009
Ref: using/configure cmdoption-enable-framework6460184
Ref: 1f6f6460184
Ref: using/configure cmdoption-16460216
Ref: 1f706460216
Ref: using/configure cmdoption-with-universal-archs6460412
Ref: 1f716460412
Ref: using/configure cmdoption-with-framework-name6461213
Ref: 1f726461213
Ref: using/configure cmdoption-with-app-store-compliance6461399
Ref: 16fc6461399
Ref: using/configure cmdoption-26461440
Ref: 1f736461440
Ref: macOS Options-Footnote-16461942
Ref: macOS Options-Footnote-26462009
Node: iOS Options6462107
Ref: using/configure ios-options6462226
Ref: 1f746462226
Ref: using/configure cmdoption-36462293
Ref: 1f756462293
Ref: using/configure cmdoption-46462462
Ref: 1f766462462
Ref: iOS Options-Footnote-16462609
Node: Cross Compiling Options6462676
Ref: using/configure cross-compiling-options6462773
Ref: 1f776462773
Ref: using/configure cmdoption-build6463120
Ref: 1f786463120
Ref: using/configure cmdoption-host6463225
Ref: 1f796463225
Ref: using/configure cmdoption-with-build-python6463321
Ref: 1f7a6463321
Ref: using/configure cmdoption-arg-CONFIG_SITE6463458
Ref: 1f7b6463458
Ref: using/configure cmdoption-arg-HOSTRUNNER6463743
Ref: 1f7c6463743
Node: Python Build System6464078
Ref: using/configure python-build-system6464210
Ref: 1f7d6464210
Node: Main files of the build system6464372
Ref: using/configure main-files-of-the-build-system6464483
Ref: 1f7e6464483
Node: Main build steps6464846
Ref: using/configure main-build-steps6464987
Ref: 1f7f6464987
Node: Main Makefile targets6465367
Ref: using/configure main-makefile-targets6465490
Ref: 1f806465490
Node: make6465715
Ref: using/configure make6465799
Ref: 1f816465799
Node: make platform6467208
Ref: using/configure make-platform6467317
Ref: 1f826467317
Node: make profile-opt6467635
Ref: using/configure make-profile-opt6467750
Ref: 1f836467750
Node: make clean6468018
Ref: using/configure make-clean6468134
Ref: 1f846468134
Node: make distclean6468194
Ref: using/configure make-distclean6468306
Ref: 1f856468306
Ref: make distclean-Footnote-16468551
Node: make install6468974
Ref: using/configure make-install6469085
Ref: 1f866469085
Node: make test6469176
Ref: using/configure make-test6469290
Ref: 1f876469290
Node: make buildbottest6469631
Ref: using/configure make-buildbottest6469747
Ref: 1f886469747
Node: make regen-all6469945
Ref: using/configure make-regen-all6470043
Ref: 1f896470043
Node: C extensions6470344
Ref: using/configure c-extensions6470442
Ref: 1f8a6470442
Node: Compiler and linker flags6472110
Ref: using/configure compiler-and-linker-flags6472216
Ref: 1f8b6472216
Node: Preprocessor flags6472449
Ref: using/configure preprocessor-flags6472552
Ref: 1f8c6472552
Ref: using/configure envvar-CONFIGURE_CPPFLAGS6472607
Ref: 1f8d6472607
Ref: using/configure envvar-CPPFLAGS6472772
Ref: 15086472772
Ref: using/configure envvar-BASECPPFLAGS6473149
Ref: 1f8e6473149
Ref: using/configure envvar-PY_CPPFLAGS6473217
Ref: 1f8f6473217
Node: Compiler flags6473470
Ref: using/configure compiler-flags6473594
Ref: 1f906473594
Ref: using/configure envvar-CC6473641
Ref: 15056473641
Ref: using/configure envvar-CXX6473732
Ref: 1f916473732
Ref: using/configure envvar-CFLAGS6473826
Ref: 15066473826
Ref: using/configure envvar-CFLAGS_NODIST6473884
Ref: 1f926473884
Ref: using/configure envvar-COMPILEALL_OPTS6474690
Ref: 1f936474690
Ref: using/configure envvar-EXTRA_CFLAGS6474898
Ref: 1f946474898
Ref: using/configure envvar-CONFIGURE_CFLAGS6474968
Ref: 1f956474968
Ref: using/configure envvar-CONFIGURE_CFLAGS_NODIST6475129
Ref: 1f966475129
Ref: using/configure envvar-BASECFLAGS6475304
Ref: 1f976475304
Ref: using/configure envvar-OPT6475369
Ref: 1f5a6475369
Ref: using/configure envvar-CFLAGS_ALIASING6475426
Ref: 1f986475426
Ref: using/configure envvar-CCSHARED6475581
Ref: 1f996475581
Ref: using/configure envvar-CFLAGSFORSHARED6475730
Ref: 1f9a6475730
Ref: using/configure envvar-PY_CFLAGS6475951
Ref: 1f9b6475951
Ref: using/configure envvar-PY_CFLAGS_NODIST6476082
Ref: 1f9c6476082
Ref: using/configure envvar-PY_STDMODULE_CFLAGS6476254
Ref: 1f9d6476254
Ref: using/configure envvar-PY_CORE_CFLAGS6476485
Ref: 1f9e6476485
Ref: using/configure envvar-PY_BUILTIN_MODULE_CFLAGS6476616
Ref: 1f9f6476616
Ref: using/configure envvar-PURIFY6476892
Ref: 1fa06476892
Ref: Compiler flags-Footnote-16477062
Node: Linker flags6477117
Ref: using/configure linker-flags6477214
Ref: 1fa16477214
Ref: using/configure envvar-LINKCC6477257
Ref: 1fa26477257
Ref: using/configure envvar-CONFIGURE_LDFLAGS6477418
Ref: 1fa36477418
Ref: using/configure envvar-LDFLAGS_NODIST6477765
Ref: 1fa46477765
Ref: using/configure envvar-CONFIGURE_LDFLAGS_NODIST6478362
Ref: 1fa56478362
Ref: using/configure envvar-LDFLAGS6478539
Ref: 15076478539
Ref: using/configure envvar-LIBS6478885
Ref: 1fa66478885
Ref: using/configure envvar-LDSHARED6479036
Ref: 1fa76479036
Ref: using/configure envvar-BLDSHARED6479160
Ref: 1fa86479160
Ref: using/configure envvar-PY_LDFLAGS6479305
Ref: 1fa96479305
Ref: using/configure envvar-PY_LDFLAGS_NODIST6479397
Ref: 1faa6479397
Ref: using/configure envvar-PY_CORE_LDFLAGS6479538
Ref: 1fab6479538
Ref: Linker flags-Footnote-16479712
Node: Using Python on Windows6479767
Ref: using/windows doc6479904
Ref: 1fac6479904
Ref: using/windows translation-repo6479904
Ref: 1fad6479904
Ref: using/windows using-on-windows6479904
Ref: using/windows using-python-on-windows6479904
Ref: 1fae6479904
Ref: Using Python on Windows-Footnote-16482182
Ref: Using Python on Windows-Footnote-26482224
Node: The full installer6482266
Ref: using/windows the-full-installer6482380
Ref: 1fb26482380
Ref: using/windows windows-full6482380
Ref: 1faf6482380
Node: Installation steps6482625
Ref: using/windows installation-steps6482739
Ref: 1fb36482739
Node: Removing the MAX_PATH Limitation6484872
Ref: using/windows max-path6485016
Ref: c626485016
Ref: using/windows removing-the-max-path-limitation6485016
Ref: 1fb56485016
Node: Installing Without UI6485876
Ref: using/windows install-quiet-option6486032
Ref: 5f16486032
Ref: using/windows installing-without-ui6486032
Ref: 1fb66486032
Node: Installing Without Downloading6496526
Ref: using/windows install-layout-option6496670
Ref: 1fb46496670
Ref: using/windows installing-without-downloading6496670
Ref: 1fb76496670
Node: Modifying an install6497665
Ref: using/windows modifying-an-install6497821
Ref: 1fb86497821
Node: Installing Free-threaded Binaries6498710
Ref: using/windows install-freethreaded-windows6498827
Ref: 1726498827
Ref: using/windows installing-free-threaded-binaries6498827
Ref: 1fb96498827
Ref: Installing Free-threaded Binaries-Footnote-16500739
Node: The Microsoft Store package6500781
Ref: using/windows the-microsoft-store-package6500926
Ref: 1fba6500926
Ref: using/windows windows-store6500926
Ref: 1d7a6500926
Node: Known issues6503086
Ref: using/windows known-issues6503162
Ref: 1fbb6503162
Node: Redirection of local data registry and temporary paths6503331
Ref: using/windows redirection-of-local-data-registry-and-temporary-paths6503434
Ref: 1fbc6503434
Ref: Redirection of local data registry and temporary paths-Footnote-16505659
Node: The nuget org packages6505750
Ref: using/windows the-nuget-org-packages6505899
Ref: 1fbd6505899
Ref: using/windows windows-nuget6505899
Ref: 1fb06505899
Ref: The nuget org packages-Footnote-16508283
Ref: The nuget org packages-Footnote-26508314
Ref: The nuget org packages-Footnote-36508360
Ref: The nuget org packages-Footnote-46508409
Node: Free-threaded packages6508460
Ref: using/windows free-threaded-packages6508541
Ref: 1fbe6508541
Ref: Free-threaded packages-Footnote-16509143
Ref: Free-threaded packages-Footnote-26509202
Ref: Free-threaded packages-Footnote-36509264
Node: The embeddable package6509328
Ref: using/windows the-embeddable-package6509469
Ref: 1fbf6509469
Ref: using/windows windows-embeddable6509469
Ref: 1fb16509469
Ref: The embeddable package-Footnote-16511254
Node: Python Application6511368
Ref: using/windows python-application6511470
Ref: 1fc06511470
Node: Embedding Python6512967
Ref: using/windows embedding-python6513069
Ref: 1fc16513069
Node: Alternative bundles6513857
Ref: using/windows alternative-bundles6513994
Ref: 1fc26513994
Ref: Alternative bundles-Footnote-16514941
Ref: Alternative bundles-Footnote-26514994
Ref: Alternative bundles-Footnote-36515037
Ref: Alternative bundles-Footnote-46515089
Ref: Alternative bundles-Footnote-56515256
Node: Configuring Python6515293
Ref: using/windows configuring-python6515418
Ref: 1fc36515418
Node: Excursus Setting environment variables6515986
Ref: using/windows excursus-setting-environment-variables6516117
Ref: 1fc46516117
Ref: using/windows setting-envvars6516117
Ref: 1d7b6516117
Node: Finding the Python executable6518291
Ref: using/windows finding-the-python-executable6518422
Ref: 1fc56518422
Ref: using/windows windows-path-mod6518422
Ref: 108e6518422
Node: UTF-8 mode6519716
Ref: using/windows utf-8-mode6519849
Ref: 1fc66519849
Ref: using/windows win-utf8-mode6519849
Ref: 1fc76519849
Ref: UTF-8 mode-Footnote-16521372
Ref: UTF-8 mode-Footnote-26521414
Node: Python Launcher for Windows6521456
Ref: using/windows launcher6521586
Ref: 5c16521586
Ref: using/windows python-launcher-for-windows6521586
Ref: 1fc86521586
Ref: Python Launcher for Windows-Footnote-16522440
Node: Getting started6522482
Ref: using/windows getting-started6522583
Ref: 1fc96522583
Node: From the command-line6522738
Ref: using/windows from-the-command-line6522840
Ref: 1fca6522840
Ref: From the command-line-Footnote-16525346
Node: Virtual environments6525388
Ref: using/windows virtual-environments6525512
Ref: 1fcb6525512
Node: From a script6526010
Ref: using/windows from-a-script6526135
Ref: 1fcc6526135
Node: From file associations6527181
Ref: using/windows from-file-associations6527277
Ref: 1fcd6527277
Node: Shebang Lines6527854
Ref: using/windows shebang-lines6527990
Ref: 1fce6527990
Node: Arguments in shebang lines6532042
Ref: using/windows arguments-in-shebang-lines6532176
Ref: 1fd06532176
Node: Customization6532466
Ref: using/windows customization6532598
Ref: 1fd16532598
Node: Customization via INI files6532725
Ref: using/windows customization-via-ini-files6532846
Ref: 1fd26532846
Ref: using/windows launcher-ini6532846
Ref: 1fcf6532846
Node: Customizing default Python versions6533532
Ref: using/windows customizing-default-python-versions6533653
Ref: 1fd36533653
Node: Diagnostics6537491
Ref: using/windows diagnostics6537604
Ref: 1fd46537604
Node: Dry Run6538092
Ref: using/windows dry-run6538209
Ref: 1fd56538209
Node: Install on demand6538641
Ref: using/windows install-on-demand6538759
Ref: 1fd66538759
Node: Return codes6539340
Ref: using/windows return-codes6539442
Ref: 1fd76539442
Node: Finding modules6541197
Ref: using/windows finding-modules6541335
Ref: 1fd86541335
Ref: using/windows windows-finding-modules6541335
Ref: c416541335
Node: Additional modules6546413
Ref: using/windows additional-modules6546551
Ref: 1fd96546551
Node: PyWin326546954
Ref: using/windows pywin326547034
Ref: 1fdb6547034
Ref: PyWin32-Footnote-16547618
Ref: PyWin32-Footnote-26547660
Ref: PyWin32-Footnote-36547749
Ref: PyWin32-Footnote-46547818
Ref: PyWin32-Footnote-56547912
Ref: PyWin32-Footnote-66547971
Node: cx_Freeze6548021
Ref: using/windows cx-freeze6548101
Ref: 1fdc6548101
Ref: cx_Freeze-Footnote-16548377
Node: Compiling Python on Windows6548429
Ref: using/windows compiling-python-on-windows6548567
Ref: 1fdd6548567
Ref: Compiling Python on Windows-Footnote-16549222
Ref: Compiling Python on Windows-Footnote-26549271
Node: Other Platforms6549334
Ref: using/windows other-platforms6549445
Ref: 1fdf6549445
Ref: Other Platforms-Footnote-16550008
Ref: Other Platforms-Footnote-26550050
Ref: Other Platforms-Footnote-36550092
Ref: Other Platforms-Footnote-46550147
Ref: Other Platforms-Footnote-56550175
Ref: Other Platforms-Footnote-66550232
Node: Using Python on macOS6550282
Ref: using/mac doc6550426
Ref: 1fe06550426
Ref: using/mac translation-repo6550426
Ref: 1fe16550426
Ref: using/mac using-on-mac6550426
Ref: 1fe26550426
Ref: using/mac using-python-on-macos6550426
Ref: 1fe36550426
Ref: using/mac getting-osx6551135
Ref: 1fe56551135
Ref: Using Python on macOS-Footnote-16551396
Node: Using Python for macOS from python org6551438
Ref: using/mac getting-and-installing-macpython6551568
Ref: 1fe66551568
Ref: using/mac using-python-for-macos-from-python-org6551568
Ref: 1fe76551568
Node: Installation steps<2>6551753
Ref: using/mac installation-steps6551884
Ref: 1fe86551884
Ref: Installation steps<2>-Footnote-16556974
Ref: Installation steps<2>-Footnote-26557016
Ref: Installation steps<2>-Footnote-36557064
Ref: Installation steps<2>-Footnote-46557119
Ref: Installation steps<2>-Footnote-56557166
Node: How to run a Python script6557215
Ref: using/mac how-to-run-a-python-script6557346
Ref: 1fe96557346
Node: Alternative Distributions6559321
Ref: using/mac alternative-bundles6559497
Ref: 1fe46559497
Ref: using/mac alternative-distributions6559497
Ref: 1feb6559497
Ref: Alternative Distributions-Footnote-16560571
Ref: Alternative Distributions-Footnote-26560624
Ref: Alternative Distributions-Footnote-36560667
Ref: Alternative Distributions-Footnote-46560691
Node: Installing Additional Python Packages6560724
Ref: using/mac installing-additional-python-packages6560877
Ref: 1fec6560877
Ref: using/mac mac-package-manager6560877
Ref: 1fed6560877
Ref: using/mac osx-gui-scripts6561031
Ref: 1fee6561031
Ref: Installing Additional Python Packages-Footnote-16561069
Node: GUI Programming6561148
Ref: using/mac gui-programming6561291
Ref: 1fef6561291
Ref: using/mac gui-programming-on-the-mac6561291
Ref: 1ff06561291
Ref: GUI Programming-Footnote-16562230
Ref: GUI Programming-Footnote-26562271
Ref: GUI Programming-Footnote-36562311
Ref: GUI Programming-Footnote-46562352
Ref: GUI Programming-Footnote-56562406
Ref: GUI Programming-Footnote-66562431
Ref: GUI Programming-Footnote-76562467
Ref: GUI Programming-Footnote-86562495
Node: Advanced Topics6562524
Ref: using/mac advanced-topics6562645
Ref: 1ff16562645
Node: Installing Free-threaded Binaries<2>6562875
Ref: using/mac install-freethreaded-macos6563005
Ref: 1736563005
Ref: using/mac installing-free-threaded-binaries6563005
Ref: 1ff26563005
Ref: Installing Free-threaded Binaries<2>-Footnote-16567994
Node: Installing using the command line6568036
Ref: using/mac installing-using-the-command-line6568207
Ref: 1ff36568207
Node: Distributing Python Applications6571035
Ref: using/mac distributing-python-applications6571190
Ref: 1ff46571190
Ref: using/mac distributing-python-applications-on-the-mac6571190
Ref: 1ff56571190
Ref: Distributing Python Applications-Footnote-16571818
Ref: Distributing Python Applications-Footnote-26571859
Ref: Distributing Python Applications-Footnote-36571900
Ref: Distributing Python Applications-Footnote-46571928
Node: App Store Compliance6571961
Ref: using/mac app-store-compliance6572074
Ref: 1ff66572074
Ref: App Store Compliance-Footnote-16573184
Node: Other Resources6573278
Ref: using/mac other-resources6573375
Ref: 1ff76573375
Ref: Other Resources-Footnote-16573641
Ref: Other Resources-Footnote-26573684
Node: Using Python on Android6573753
Ref: using/android doc6573893
Ref: 1ff86573893
Ref: using/android translation-repo6573893
Ref: 1ff96573893
Ref: using/android using-android6573893
Ref: 1ffa6573893
Ref: using/android using-python-on-android6573893
Ref: 1ffb6573893
Node: Adding Python to an Android app6575128
Ref: using/android adding-python-to-an-android-app6575265
Ref: 1ffe6575265
Ref: Adding Python to an Android app-Footnote-16576588
Ref: Adding Python to an Android app-Footnote-26576629
Ref: Adding Python to an Android app-Footnote-36576670
Ref: Adding Python to an Android app-Footnote-46576706
Ref: Adding Python to an Android app-Footnote-56576773
Ref: Adding Python to an Android app-Footnote-66576804
Ref: Adding Python to an Android app-Footnote-76576872
Ref: Adding Python to an Android app-Footnote-86576942
Ref: Adding Python to an Android app-Footnote-96577032
Ref: Adding Python to an Android app-Footnote-106577154
Node: Building a Python package for Android6577255
Ref: using/android building-a-python-package-for-android6577392
Ref: 1fff6577392
Ref: Building a Python package for Android-Footnote-16577777
Node: Using Python on iOS6577843
Ref: using/ios doc6577978
Ref: 20006577978
Ref: using/ios translation-repo6577978
Ref: 20016577978
Ref: using/ios using-ios6577978
Ref: 20026577978
Ref: using/ios using-python-on-ios6577978
Ref: 20036577978
Ref: Using Python on iOS-Footnote-16579511
Ref: Using Python on iOS-Footnote-26579539
Node: Python at runtime on iOS6579564
Ref: using/ios python-at-runtime-on-ios6579677
Ref: 20046579677
Node: iOS version compatibility6579898
Ref: using/ios ios-version-compatibility6580016
Ref: 20056580016
Node: Platform identification6580548
Ref: using/ios platform-identification6580704
Ref: 20066580704
Node: Standard library availability6581346
Ref: using/ios standard-library-availability6581501
Ref: 20096581501
Node: Binary extension modules6581724
Ref: using/ios binary-extension-modules6581878
Ref: 200a6581878
Node: Compiler stub binaries6584736
Ref: using/ios compiler-stub-binaries6584852
Ref: 200e6584852
Node: Installing Python on iOS6586244
Ref: using/ios installing-python-on-ios6586389
Ref: 200f6586389
Node: Tools for building iOS apps6586559
Ref: using/ios tools-for-building-ios-apps6586687
Ref: 20106586687
Node: Adding Python to an iOS project6587470
Ref: using/ios adding-ios6587631
Ref: 200b6587631
Ref: using/ios adding-python-to-an-ios-project6587631
Ref: 20116587631
Ref: Adding Python to an iOS project-Footnote-16596812
Ref: Adding Python to an iOS project-Footnote-26596857
Node: Testing a Python package6596924
Ref: using/ios testing-a-python-package6597049
Ref: 20136597049
Ref: Testing a Python package-Footnote-16599489
Ref: Testing a Python package-Footnote-26599553
Node: App Store Compliance<2>6599620
Ref: using/ios app-store-compliance6599732
Ref: 20146599732
Ref: App Store Compliance<2>-Footnote-16600623
Node: Editors and IDEs6600717
Ref: using/editors doc6600820
Ref: 20156600820
Ref: using/editors editors6600820
Ref: 1fea6600820
Ref: using/editors editors-and-ides6600820
Ref: 20166600820
Ref: using/editors translation-repo6600820
Ref: 20176600820
Ref: Editors and IDEs-Footnote-16601132
Node: IDLE — Python editor and shell6601174
Ref: using/editors idle-python-editor-and-shell6601290
Ref: 20186601290
Node: Other Editors and IDEs6601629
Ref: using/editors other-editors-and-ides6601745
Ref: 20196601745
Ref: Other Editors and IDEs-Footnote-16602032
Ref: Other Editors and IDEs-Footnote-26602083
Node: The Python Language Reference6602154
Ref: reference/index doc6602290
Ref: 201a6602290
Ref: reference/index reference-index6602290
Ref: 1456602290
Ref: reference/index the-python-language-reference6602290
Ref: 201b6602290
Ref: reference/index translation-repo6602290
Ref: 201c6602290
Node: Introduction<5>6603281
Ref: reference/introduction doc6603387
Ref: 201d6603387
Ref: reference/introduction id16603387
Ref: 201e6603387
Ref: reference/introduction introduction6603387
Ref: 201f6603387
Node: Alternate Implementations6605182
Ref: reference/introduction alternate-implementations6605276
Ref: 20206605276
Ref: reference/introduction implementations6605276
Ref: 1ecf6605276
Ref: Alternate Implementations-Footnote-16607456
Ref: Alternate Implementations-Footnote-26607488
Ref: Alternate Implementations-Footnote-36607525
Ref: Alternate Implementations-Footnote-46607557
Node: Notation6607583
Ref: reference/introduction id26607677
Ref: 20216607677
Ref: reference/introduction notation6607677
Ref: 20226607677
Ref: reference/introduction grammar-token-notation-name6607864
Ref: 20236607864
Ref: reference/introduction grammar-token-notation-lc_letter6607938
Ref: 20246607938
Ref: Notation-Footnote-16610008
Node: Lexical analysis6610071
Ref: reference/lexical_analysis doc6610196
Ref: 20256610196
Ref: reference/lexical_analysis lexical6610196
Ref: 20266610196
Ref: reference/lexical_analysis lexical-analysis6610196
Ref: 20276610196
Ref: reference/lexical_analysis translation-repo6610196
Ref: 20286610196
Ref: Lexical analysis-Footnote-16610883
Node: Line structure6610925
Ref: reference/lexical_analysis id16611013
Ref: 202a6611013
Ref: reference/lexical_analysis line-structure6611013
Ref: 202b6611013
Node: Logical lines6611319
Ref: reference/lexical_analysis id26611406
Ref: 202c6611406
Ref: reference/lexical_analysis logical-lines6611406
Ref: 202d6611406
Node: Physical lines6611784
Ref: reference/lexical_analysis id36611888
Ref: 202e6611888
Ref: reference/lexical_analysis physical-lines6611888
Ref: 202f6611888
Node: Comments6612659
Ref: reference/lexical_analysis comments6612771
Ref: 20306612771
Ref: reference/lexical_analysis id46612771
Ref: 20316612771
Node: Encoding declarations6613074
Ref: reference/lexical_analysis encoding-declarations6613193
Ref: 20326613193
Ref: reference/lexical_analysis encodings6613193
Ref: 20336613193
Node: Explicit line joining6614317
Ref: reference/lexical_analysis explicit-joining6614449
Ref: 20346614449
Ref: reference/lexical_analysis explicit-line-joining6614449
Ref: 20356614449
Node: Implicit line joining6615383
Ref: reference/lexical_analysis implicit-joining6615505
Ref: 20366615505
Ref: reference/lexical_analysis implicit-line-joining6615505
Ref: 20376615505
Node: Blank lines6616341
Ref: reference/lexical_analysis blank-lines6616453
Ref: 20386616453
Ref: reference/lexical_analysis id56616453
Ref: 20396616453
Node: Indentation6616928
Ref: reference/lexical_analysis id66617044
Ref: 203a6617044
Ref: reference/lexical_analysis indentation6617044
Ref: 203b6617044
Node: Whitespace between tokens6620430
Ref: reference/lexical_analysis whitespace6620526
Ref: 203c6620526
Ref: reference/lexical_analysis whitespace-between-tokens6620526
Ref: 203d6620526
Node: Other tokens6620928
Ref: reference/lexical_analysis id76621049
Ref: 203e6621049
Ref: reference/lexical_analysis other-tokens6621049
Ref: 203f6621049
Node: Identifiers and keywords6621481
Ref: reference/lexical_analysis identifiers6621596
Ref: 20406621596
Ref: reference/lexical_analysis identifiers-and-keywords6621596
Ref: 20416621596
Ref: reference/lexical_analysis grammar-token-python-grammar-identifier6622468
Ref: 20426622468
Ref: reference/lexical_analysis grammar-token-python-grammar-id_start6622540
Ref: 20456622540
Ref: reference/lexical_analysis grammar-token-python-grammar-id_continue6622689
Ref: 20466622689
Ref: reference/lexical_analysis grammar-token-python-grammar-xid_start6622849
Ref: 20436622849
Ref: reference/lexical_analysis grammar-token-python-grammar-xid_continue6622969
Ref: 20446622969
Ref: Identifiers and keywords-Footnote-16624002
Ref: Identifiers and keywords-Footnote-26624044
Ref: Identifiers and keywords-Footnote-36624086
Node: Keywords6624149
Ref: reference/lexical_analysis id86624240
Ref: 20476624240
Ref: reference/lexical_analysis keywords6624240
Ref: 20486624240
Node: Soft Keywords6624835
Ref: reference/lexical_analysis id96624966
Ref: 20496624966
Ref: reference/lexical_analysis soft-keywords6624966
Ref: 8126624966
Node: Reserved classes of identifiers6625676
Ref: reference/lexical_analysis id-classes6625790
Ref: 204a6625790
Ref: reference/lexical_analysis reserved-classes-of-identifiers6625790
Ref: 204b6625790
Node: Literals6627713
Ref: reference/lexical_analysis id106627825
Ref: 204d6627825
Ref: reference/lexical_analysis literals6627825
Ref: 204e6627825
Node: String and Bytes literals6628104
Ref: reference/lexical_analysis string-and-bytes-literals6628211
Ref: 204f6628211
Ref: reference/lexical_analysis strings6628211
Ref: 20506628211
Ref: reference/lexical_analysis grammar-token-python-grammar-stringliteral6628349
Ref: 20516628349
Ref: reference/lexical_analysis grammar-token-python-grammar-stringprefix6628454
Ref: 20526628454
Ref: reference/lexical_analysis grammar-token-python-grammar-shortstring6628594
Ref: 20536628594
Ref: reference/lexical_analysis grammar-token-python-grammar-longstring6628697
Ref: 20546628697
Ref: reference/lexical_analysis grammar-token-python-grammar-shortstringitem6628806
Ref: 20556628806
Ref: reference/lexical_analysis grammar-token-python-grammar-longstringitem6628891
Ref: 20566628891
Ref: reference/lexical_analysis grammar-token-python-grammar-shortstringchar6628975
Ref: 20576628975
Ref: reference/lexical_analysis grammar-token-python-grammar-longstringchar6629058
Ref: 20596629058
Ref: reference/lexical_analysis grammar-token-python-grammar-stringescapeseq6629117
Ref: 20586629117
Ref: reference/lexical_analysis grammar-token-python-grammar-bytesliteral6629170
Ref: 205a6629170
Ref: reference/lexical_analysis grammar-token-python-grammar-bytesprefix6629269
Ref: 205b6629269
Ref: reference/lexical_analysis grammar-token-python-grammar-shortbytes6629359
Ref: 205c6629359
Ref: reference/lexical_analysis grammar-token-python-grammar-longbytes6629459
Ref: 205d6629459
Ref: reference/lexical_analysis grammar-token-python-grammar-shortbytesitem6629565
Ref: 205e6629565
Ref: reference/lexical_analysis grammar-token-python-grammar-longbytesitem6629647
Ref: 205f6629647
Ref: reference/lexical_analysis grammar-token-python-grammar-shortbyteschar6629728
Ref: 20606629728
Ref: reference/lexical_analysis grammar-token-python-grammar-longbyteschar6629809
Ref: 20626629809
Ref: reference/lexical_analysis grammar-token-python-grammar-bytesescapeseq6629866
Ref: 20616629866
Ref: String and Bytes literals-Footnote-16632406
Node: Escape sequences6632448
Ref: reference/lexical_analysis escape-sequences6632526
Ref: 45d6632526
Ref: reference/lexical_analysis id116632526
Ref: 20636632526
Ref: Escape sequences-Footnote-16638849
Node: String literal concatenation6638921
Ref: reference/lexical_analysis string-concatenation6639046
Ref: 20646639046
Ref: reference/lexical_analysis string-literal-concatenation6639046
Ref: 20656639046
Ref: reference/lexical_analysis f-strings6640089
Ref: 9b46640089
Node: f-strings6640089
Ref: reference/lexical_analysis formatted-string-literals6640205
Ref: 20666640205
Ref: reference/lexical_analysis id136640205
Ref: 20676640205
Ref: reference/lexical_analysis grammar-token-python-grammar-f_string6640786
Ref: 20686640786
Ref: reference/lexical_analysis grammar-token-python-grammar-replacement_field6640889
Ref: 206a6640889
Ref: reference/lexical_analysis grammar-token-python-grammar-f_expression6641017
Ref: 206b6641017
Ref: reference/lexical_analysis grammar-token-python-grammar-conversion6641275
Ref: 206c6641275
Ref: reference/lexical_analysis grammar-token-python-grammar-format_spec6641318
Ref: 206d6641318
Ref: reference/lexical_analysis grammar-token-python-grammar-literal_char6641407
Ref: 20696641407
Ref: f-strings-Footnote-16646937
Node: Numeric literals6646979
Ref: reference/lexical_analysis numbers6647083
Ref: 20716647083
Ref: reference/lexical_analysis numeric-literals6647083
Ref: 20726647083
Node: Integer literals6647517
Ref: reference/lexical_analysis integer-literals6647635
Ref: 20736647635
Ref: reference/lexical_analysis integers6647635
Ref: 20746647635
Ref: reference/lexical_analysis grammar-token-python-grammar-integer6647756
Ref: 20756647756
Ref: reference/lexical_analysis grammar-token-python-grammar-decinteger6647880
Ref: 20766647880
Ref: reference/lexical_analysis grammar-token-python-grammar-bininteger6647976
Ref: 20776647976
Ref: reference/lexical_analysis grammar-token-python-grammar-octinteger6648045
Ref: 20786648045
Ref: reference/lexical_analysis grammar-token-python-grammar-hexinteger6648114
Ref: 20796648114
Ref: reference/lexical_analysis grammar-token-python-grammar-nonzerodigit6648183
Ref: 207a6648183
Ref: reference/lexical_analysis grammar-token-python-grammar-digit6648215
Ref: 207b6648215
Ref: reference/lexical_analysis grammar-token-python-grammar-bindigit6648247
Ref: 207c6648247
Ref: reference/lexical_analysis grammar-token-python-grammar-octdigit6648279
Ref: 207d6648279
Ref: reference/lexical_analysis grammar-token-python-grammar-hexdigit6648311
Ref: 207e6648311
Node: Floating-point literals6649178
Ref: reference/lexical_analysis floating6649298
Ref: 207f6649298
Ref: reference/lexical_analysis floating-point-literals6649298
Ref: 20806649298
Ref: reference/lexical_analysis grammar-token-python-grammar-floatnumber6649440
Ref: 20816649440
Ref: reference/lexical_analysis grammar-token-python-grammar-pointfloat6649516
Ref: 20826649516
Ref: reference/lexical_analysis grammar-token-python-grammar-exponentfloat6649615
Ref: 20836649615
Ref: reference/lexical_analysis grammar-token-python-grammar-digitpart6649711
Ref: 20846649711
Ref: reference/lexical_analysis grammar-token-python-grammar-fraction6649781
Ref: 20856649781
Ref: reference/lexical_analysis grammar-token-python-grammar-exponent6649831
Ref: 20866649831
Node: Imaginary literals6650410
Ref: reference/lexical_analysis imaginary6650505
Ref: 20876650505
Ref: reference/lexical_analysis imaginary-literals6650505
Ref: 20886650505
Ref: reference/lexical_analysis grammar-token-python-grammar-imagnumber6650632
Ref: 20896650632
Node: Operators6651121
Ref: reference/lexical_analysis id146651219
Ref: 208a6651219
Ref: reference/lexical_analysis operators6651219
Ref: 208b6651219
Node: Delimiters6651456
Ref: reference/lexical_analysis delimiters6651537
Ref: 208c6651537
Ref: reference/lexical_analysis id156651537
Ref: 208d6651537
Node: Data model6652460
Ref: reference/datamodel doc6652585
Ref: 208e6652585
Ref: reference/datamodel data-model6652585
Ref: 208f6652585
Ref: reference/datamodel datamodel6652585
Ref: 1b036652585
Ref: reference/datamodel translation-repo6652585
Ref: 20906652585
Node: Objects values and types6652753
Ref: reference/datamodel objects6652860
Ref: 20916652860
Ref: reference/datamodel objects-values-and-types6652860
Ref: 20926652860
Ref: Objects values and types-Footnote-16657796
Node: The standard type hierarchy6658023
Ref: reference/datamodel the-standard-type-hierarchy6658159
Ref: 20936658159
Ref: reference/datamodel types6658159
Ref: 20946658159
Node: None6659169
Ref: reference/datamodel none6659260
Ref: 20956659260
Node: NotImplemented6659593
Ref: reference/datamodel notimplemented6659701
Ref: 20966659701
Node: Ellipsis6660522
Ref: reference/datamodel ellipsis6660640
Ref: 20986660640
Node: numbers Number6660866
Ref: reference/datamodel numbers-number6660979
Ref: 20996660979
Node: numbers Integral6662210
Ref: reference/datamodel numbers-integral6662304
Ref: 209a6662304
Node: numbers Real float6663527
Ref: reference/datamodel numbers-real-float6663653
Ref: 209b6663653
Node: numbers Complex complex6664238
Ref: reference/datamodel numbers-complex-complex6664339
Ref: 209c6664339
Node: Sequences6664719
Ref: reference/datamodel sequences6664833
Ref: 209d6664833
Node: Immutable sequences6665992
Ref: reference/datamodel immutable-sequences6666083
Ref: 209e6666083
Node: Mutable sequences6668054
Ref: reference/datamodel mutable-sequences6668145
Ref: 20a06668145
Node: Set types6669121
Ref: reference/datamodel set-types6669229
Ref: 20a16669229
Node: Mappings6670462
Ref: reference/datamodel mappings6670575
Ref: 20a36670575
Node: Dictionaries<2>6671057
Ref: reference/datamodel dictionaries6671117
Ref: 20a46671117
Node: Callable types6672556
Ref: reference/datamodel callable-types6672670
Ref: 20a56672670
Node: User-defined functions6673055
Ref: reference/datamodel user-defined-funcs6673153
Ref: 2996673153
Ref: reference/datamodel user-defined-functions6673153
Ref: 20a66673153
Node: Special read-only attributes6673532
Ref: reference/datamodel special-read-only-attributes6673655
Ref: 20a76673655
Ref: reference/datamodel function __builtins__6674054
Ref: 20a86674054
Ref: reference/datamodel function __globals__6674499
Ref: 131b6674499
Ref: reference/datamodel function __closure__6675005
Ref: 13186675005
Node: Special writable attributes6675769
Ref: reference/datamodel special-writable-attributes6675892
Ref: 20ab6675892
Ref: reference/datamodel function __doc__6676348
Ref: 121e6676348
Ref: reference/datamodel function __name__6676640
Ref: 131c6676640
Ref: reference/datamodel function __qualname__6676933
Ref: 20ac6676933
Ref: reference/datamodel function __module__6677379
Ref: 20ad6677379
Ref: reference/datamodel function __defaults__6677685
Ref: 13196677685
Ref: reference/datamodel function __code__6678176
Ref: 29a6678176
Ref: reference/datamodel function __dict__6678467
Ref: 131a6678467
Ref: reference/datamodel function __annotations__6678850
Ref: 121d6678850
Ref: reference/datamodel function __kwdefaults__6679473
Ref: 10636679473
Ref: reference/datamodel function __type_params__6679782
Ref: 20af6679782
Node: Instance methods6680782
Ref: reference/datamodel id26680908
Ref: 20b16680908
Ref: reference/datamodel instance-methods6680908
Ref: 1e5f6680908
Ref: reference/datamodel method __self__6681144
Ref: 14156681144
Ref: reference/datamodel method __func__6681444
Ref: 13456681444
Ref: reference/datamodel method __doc__6681661
Ref: 20b36681661
Ref: reference/datamodel method __name__6682152
Ref: 20b46682152
Ref: reference/datamodel method __module__6682447
Ref: 20b56682447
Ref: reference/datamodel method-binding6683013
Ref: 20b26683013
Node: Generator functions6684487
Ref: reference/datamodel generator-functions6684610
Ref: 20b66684610
Node: Coroutine functions6685314
Ref: reference/datamodel coroutine-functions6685453
Ref: 20b76685453
Node: Asynchronous generator functions6685857
Ref: reference/datamodel asynchronous-generator-functions6685995
Ref: 20b96685995
Node: Built-in functions6686865
Ref: reference/datamodel built-in-functions6687000
Ref: 20ba6687000
Ref: reference/datamodel builtin-functions6687000
Ref: 20b06687000
Node: Built-in methods6687790
Ref: reference/datamodel built-in-methods6687903
Ref: 20bb6687903
Ref: reference/datamodel builtin-methods6687903
Ref: 20bc6687903
Node: Classes<2>6688392
Ref: reference/datamodel classes6688502
Ref: 20bd6688502
Ref: reference/datamodel id36688502
Ref: 20be6688502
Node: Class Instances6688855
Ref: reference/datamodel class-instances6688940
Ref: 20bf6688940
Node: Modules<3>6689104
Ref: reference/datamodel module-objects6689224
Ref: 20c06689224
Ref: reference/datamodel modules6689224
Ref: 20c16689224
Node: Import-related attributes on module objects6690247
Ref: reference/datamodel import-mod-attrs6690389
Ref: 20c36690389
Ref: reference/datamodel import-related-attributes-on-module-objects6690389
Ref: 20c46690389
Ref: reference/datamodel module __name__6692036
Ref: 13d86692036
Ref: reference/datamodel module __spec__6692375
Ref: 20c66692375
Ref: reference/datamodel module __package__6692634
Ref: 2d76692634
Ref: reference/datamodel module __loader__6694710
Ref: 2e26694710
Ref: reference/datamodel module __path__6695928
Ref: 1e0c6695928
Ref: reference/datamodel module __file__6696385
Ref: 20cc6696385
Ref: reference/datamodel module __cached__6696417
Ref: 2d56696417
Ref: Import-related attributes on module objects-Footnote-16698400
Ref: Import-related attributes on module objects-Footnote-26698442
Node: Other writable attributes on module objects6698484
Ref: reference/datamodel other-writable-attributes-on-module-objects6698654
Ref: 20ce6698654
Ref: reference/datamodel module __doc__6698877
Ref: 19936698877
Ref: reference/datamodel module __annotations__6699028
Ref: 20cf6699028
Node: Module dictionaries6699300
Ref: reference/datamodel module-dictionaries6699418
Ref: 20d06699418
Ref: reference/datamodel module __dict__6699546
Ref: 20d16699546
Node: Custom classes6700164
Ref: reference/datamodel class-attrs-and-methods6700285
Ref: 20d26700285
Ref: reference/datamodel custom-classes6700285
Ref: 20d36700285
Node: Special attributes6701902
Ref: reference/datamodel special-attributes6701995
Ref: 20d46701995
Ref: reference/datamodel type __name__6702366
Ref: 14fa6702366
Ref: reference/datamodel type __qualname__6702656
Ref: 20d56702656
Ref: reference/datamodel type __module__6702966
Ref: 3776702966
Ref: reference/datamodel type __dict__6703241
Ref: c7e6703241
Ref: reference/datamodel type __bases__6703645
Ref: 14fb6703645
Ref: reference/datamodel type __base__6704150
Ref: 20d66704150
Ref: reference/datamodel type __doc__6704685
Ref: 1e4d6704685
Ref: reference/datamodel type __annotations__6705009
Ref: 20d86705009
Ref: reference/datamodel type __type_params__6706360
Ref: 20d96706360
Ref: reference/datamodel type __static_attributes__6706871
Ref: 14b6706871
Ref: reference/datamodel type __firstlineno__6707412
Ref: 14c6707412
Ref: reference/datamodel type __mro__6708066
Ref: 20da6708066
Node: Special methods6708370
Ref: reference/datamodel special-methods6708463
Ref: 20db6708463
Ref: reference/datamodel type mro6708636
Ref: 20dc6708636
Ref: reference/datamodel type __subclasses__6708869
Ref: 5766708869
Node: Class instances6709219
Ref: reference/datamodel id46709368
Ref: 20dd6709368
Node: Special attributes<2>6710848
Ref: reference/datamodel id56710921
Ref: 20e06710921
Ref: reference/datamodel object __class__6710978
Ref: 14fc6710978
Ref: reference/datamodel object __dict__6711062
Ref: 55e6711062
Node: I/O objects also known as file objects6711315
Ref: reference/datamodel i-o-objects-also-known-as-file-objects6711464
Ref: 20e26711464
Ref: reference/datamodel file read6712367
Ref: 20e56712367
Ref: reference/datamodel file write6712534
Ref: 20e66712534
Ref: reference/datamodel file close6712600
Ref: 20e76712600
Node: Internal types6712682
Ref: reference/datamodel internal-types6712807
Ref: 20e86712807
Node: Code objects6713181
Ref: reference/datamodel code-objects6713266
Ref: 1d26713266
Ref: reference/datamodel id66713266
Ref: 20e96713266
Node: Special read-only attributes<2>6713999
Ref: reference/datamodel id76714111
Ref: 20ea6714111
Ref: reference/datamodel codeobject co_name6714221
Ref: 20eb6714221
Ref: reference/datamodel codeobject co_qualname6714410
Ref: 20ec6714410
Ref: reference/datamodel codeobject co_argcount6714745
Ref: 20ed6714745
Ref: reference/datamodel codeobject co_posonlyargcount6715235
Ref: 20ee6715235
Ref: reference/datamodel codeobject co_kwonlyargcount6715629
Ref: 20ef6715629
Ref: reference/datamodel codeobject co_nlocals6716014
Ref: 20f06716014
Ref: reference/datamodel codeobject co_varnames6716324
Ref: 20f16716324
Ref: reference/datamodel codeobject co_cellvars6716717
Ref: 20f26716717
Ref: reference/datamodel codeobject co_freevars6717206
Ref: 20aa6717206
Ref: reference/datamodel codeobject co_code6717954
Ref: 20f56717954
Ref: reference/datamodel codeobject co_consts6718266
Ref: 16796718266
Ref: reference/datamodel codeobject co_names6718580
Ref: 20f66718580
Ref: reference/datamodel codeobject co_filename6718895
Ref: 13ba6718895
Ref: reference/datamodel codeobject co_firstlineno6719174
Ref: 20f76719174
Ref: reference/datamodel codeobject co_lnotab6719386
Ref: 2e06719386
Ref: reference/datamodel codeobject co_stacksize6720134
Ref: 20f86720134
Ref: reference/datamodel codeobject co_flags6720340
Ref: 20f96720340
Node: Methods on code objects6721463
Ref: reference/datamodel methods-on-code-objects6721575
Ref: 20fc6721575
Ref: reference/datamodel codeobject co_positions6721642
Ref: 5b66721642
Ref: reference/datamodel codeobject co_lines6723191
Ref: 2fb6723191
Ref: reference/datamodel codeobject replace6724822
Ref: 20fd6724822
Ref: Methods on code objects-Footnote-16725109
Node: Frame objects6725151
Ref: reference/datamodel frame-objects6725262
Ref: 6e36725262
Ref: reference/datamodel id86725262
Ref: 20fe6725262
Node: Special read-only attributes<3>6725615
Ref: reference/datamodel id96725735
Ref: 20ff6725735
Ref: reference/datamodel frame f_back6725839
Ref: 78f6725839
Ref: reference/datamodel frame f_code6726166
Ref: 21006726166
Ref: reference/datamodel frame f_locals6726692
Ref: 1826726692
Ref: reference/datamodel frame f_globals6727424
Ref: 21016727424
Ref: reference/datamodel frame f_builtins6727721
Ref: 21026727721
Ref: reference/datamodel frame f_lasti6728024
Ref: 88f6728024
Node: Special writable attributes<2>6728355
Ref: reference/datamodel id106728504
Ref: 21036728504
Ref: reference/datamodel frame f_trace6728607
Ref: 21046728607
Ref: reference/datamodel frame f_trace_lines6729150
Ref: bfc6729150
Ref: reference/datamodel frame f_trace_opcodes6729474
Ref: bfd6729474
Ref: reference/datamodel frame f_lineno6730077
Ref: 7b06730077
Node: Frame object methods6730620
Ref: reference/datamodel frame-object-methods6730729
Ref: 21056730729
Ref: reference/datamodel frame clear6730825
Ref: 2806730825
Node: Traceback objects6731507
Ref: reference/datamodel id116731619
Ref: 21066731619
Ref: reference/datamodel traceback-objects6731619
Ref: b0d6731619
Ref: reference/datamodel traceback tb_frame6732946
Ref: 21076732946
Ref: reference/datamodel traceback tb_lineno6733589
Ref: 21086733589
Ref: reference/datamodel traceback tb_lasti6733806
Ref: 21096733806
Ref: reference/datamodel traceback tb_next6734171
Ref: b0c6734171
Node: Slice objects6734455
Ref: reference/datamodel slice-objects6734575
Ref: 210a6734575
Ref: reference/datamodel slice indices6735022
Ref: 10626735022
Node: Static method objects6735504
Ref: reference/datamodel static-method-objects6735627
Ref: 210e6735627
Node: Class method objects6736227
Ref: reference/datamodel class-method-objects6736328
Ref: 210f6736328
Node: Special method names6736775
Ref: reference/datamodel special-method-names6736897
Ref: 21106736897
Ref: reference/datamodel specialnames6736897
Ref: c8f6736897
Ref: Special method names-Footnote-16738826
Node: Basic customization6739163
Ref: reference/datamodel basic-customization6739276
Ref: 21126739276
Ref: reference/datamodel customization6739276
Ref: 21136739276
Ref: reference/datamodel object __new__6739333
Ref: 5836739333
Ref: reference/datamodel object __init__6740849
Ref: 6b36740849
Ref: reference/datamodel object __del__6741672
Ref: 10386741672
Ref: reference/datamodel object __repr__6744875
Ref: 61f6744875
Ref: reference/datamodel object __str__6745792
Ref: 6206745792
Ref: reference/datamodel object __bytes__6746462
Ref: 5eb6746462
Ref: reference/datamodel object __format__6746718
Ref: 6216746718
Ref: reference/datamodel richcmpfuncs6747980
Ref: 21146747980
Ref: reference/datamodel object __lt__6747980
Ref: 12e76747980
Ref: reference/datamodel object __le__6748020
Ref: 13546748020
Ref: reference/datamodel object __eq__6748060
Ref: b136748060
Ref: reference/datamodel object __ne__6748100
Ref: 15676748100
Ref: reference/datamodel object __gt__6748140
Ref: 13556748140
Ref: reference/datamodel object __ge__6748180
Ref: 13566748180
Ref: reference/datamodel object __hash__6751194
Ref: b146751194
Ref: reference/datamodel object __bool__6755390
Ref: 131d6755390
Node: Customizing attribute access6755890
Ref: reference/datamodel attribute-access6756038
Ref: 21156756038
Ref: reference/datamodel customizing-attribute-access6756038
Ref: 21166756038
Ref: reference/datamodel object __getattr__6756270
Ref: 4d66756270
Ref: reference/datamodel object __getattribute__6757548
Ref: bf16757548
Ref: reference/datamodel object __setattr__6758642
Ref: 20de6758642
Ref: reference/datamodel object __delattr__6759310
Ref: 20df6759310
Ref: reference/datamodel object __dir__6759696
Ref: 15b76759696
Node: Customizing module attribute access6760032
Ref: reference/datamodel customizing-module-attribute-access6760165
Ref: 21186760165
Ref: reference/datamodel module __getattr__6760254
Ref: af76760254
Ref: reference/datamodel module __dir__6760288
Ref: af86760288
Ref: reference/datamodel module __class__6761136
Ref: 21196761136
Ref: Customizing module attribute access-Footnote-16762386
Node: Implementing Descriptors6762428
Ref: reference/datamodel descriptors6762590
Ref: c706762590
Ref: reference/datamodel implementing-descriptors6762590
Ref: 211a6762590
Ref: reference/datamodel object __get__6763150
Ref: 15376763150
Ref: reference/datamodel object __set__6764074
Ref: 211b6764074
Ref: reference/datamodel object __delete__6764425
Ref: 17136764425
Ref: reference/datamodel object __objclass__6764643
Ref: 211d6764643
Ref: Implementing Descriptors-Footnote-16765210
Node: Invoking Descriptors6765252
Ref: reference/datamodel descriptor-invocation6765391
Ref: 211c6765391
Ref: reference/datamodel invoking-descriptors6765391
Ref: 211e6765391
Node: __slots__<2>6768545
Ref: reference/datamodel id136768651
Ref: 211f6768651
Ref: reference/datamodel slots6768651
Ref: 20e16768651
Ref: reference/datamodel object __slots__6769028
Ref: 153a6769028
Ref: reference/datamodel datamodel-note-slots6769351
Ref: 21206769351
Node: Customizing class creation6772438
Ref: reference/datamodel class-customization6772607
Ref: c6c6772607
Ref: reference/datamodel customizing-class-creation6772607
Ref: 21226772607
Ref: reference/datamodel object __init_subclass__6773092
Ref: 6346773092
Ref: reference/datamodel object __set_name__6774562
Ref: c6f6774562
Node: Metaclasses6775515
Ref: reference/datamodel id146775619
Ref: 21236775619
Ref: reference/datamodel metaclasses6775619
Ref: 21246775619
Node: Resolving MRO entries6776674
Ref: reference/datamodel resolving-mro-entries6776824
Ref: 21256776824
Ref: reference/datamodel object __mro_entries__6776885
Ref: b026776885
Ref: Resolving MRO entries-Footnote-16777900
Node: Determining the appropriate metaclass6777942
Ref: reference/datamodel determining-the-appropriate-metaclass6778110
Ref: 21266778110
Node: Preparing the class namespace6779041
Ref: reference/datamodel prepare6779212
Ref: c7f6779212
Ref: reference/datamodel preparing-the-class-namespace6779212
Ref: 21276779212
Ref: Preparing the class namespace-Footnote-16780115
Node: Executing the class body6780157
Ref: reference/datamodel executing-the-class-body6780316
Ref: 21286780316
Node: Creating the class object6781051
Ref: reference/datamodel class-object-creation6781201
Ref: c6b6781201
Ref: reference/datamodel creating-the-class-object6781201
Ref: 21296781201
Ref: Creating the class object-Footnote-16783639
Node: Uses for metaclasses6783681
Ref: reference/datamodel uses-for-metaclasses6783798
Ref: 212a6783798
Node: Customizing instance and subclass checks6784109
Ref: reference/datamodel customizing-instance-and-subclass-checks6784273
Ref: 212b6784273
Ref: reference/datamodel type __instancecheck__6784763
Ref: 212c6784763
Ref: reference/datamodel type __subclasscheck__6784991
Ref: 212d6784991
Ref: Customizing instance and subclass checks-Footnote-16785943
Node: Emulating generic types6785985
Ref: reference/datamodel emulating-generic-types6786149
Ref: 212e6786149
Ref: reference/datamodel object __class_getitem__6787064
Ref: 73e6787064
Ref: Emulating generic types-Footnote-16787562
Node: The purpose of __class_getitem__6787604
Ref: reference/datamodel the-purpose-of-class-getitem6787741
Ref: 21306787741
Node: __class_getitem__ versus __getitem__6788632
Ref: reference/datamodel class-getitem-versus-getitem6788769
Ref: 21326788769
Ref: reference/datamodel classgetitem-versus-getitem6788769
Ref: 21336788769
Ref: __class_getitem__ versus __getitem__-Footnote-16792094
Node: Emulating callable objects6792136
Ref: reference/datamodel emulating-callable-objects6792285
Ref: 21376792285
Ref: reference/datamodel id156792285
Ref: 21386792285
Ref: reference/datamodel object __call__6792358
Ref: 55b6792358
Node: Emulating container types6792661
Ref: reference/datamodel emulating-container-types6792810
Ref: 21396792810
Ref: reference/datamodel sequence-types6792810
Ref: 213a6792810
Ref: reference/datamodel object __len__6795251
Ref: 15da6795251
Ref: reference/datamodel object __length_hint__6795986
Ref: f426795986
Ref: reference/datamodel object __getitem__6796775
Ref: 2836796775
Ref: reference/datamodel object __setitem__6797899
Ref: 13136797899
Ref: reference/datamodel object __delitem__6798355
Ref: 13146798355
Ref: reference/datamodel object __missing__6798775
Ref: 12026798775
Ref: reference/datamodel object __iter__6798966
Ref: c906798966
Ref: reference/datamodel object __reversed__6799273
Ref: cad6799273
Ref: reference/datamodel object __contains__6800235
Ref: 14066800235
Node: Emulating numeric types6800794
Ref: reference/datamodel emulating-numeric-types6800948
Ref: 214c6800948
Ref: reference/datamodel numeric-types6800948
Ref: 214d6800948
Ref: reference/datamodel object __add__6801263
Ref: 21456801263
Ref: reference/datamodel object __sub__6801304
Ref: 214e6801304
Ref: reference/datamodel object __mul__6801345
Ref: 21486801345
Ref: reference/datamodel object __matmul__6801386
Ref: da76801386
Ref: reference/datamodel object __truediv__6801430
Ref: ec46801430
Ref: reference/datamodel object __floordiv__6801475
Ref: 15436801475
Ref: reference/datamodel object __mod__6801521
Ref: 214f6801521
Ref: reference/datamodel object __divmod__6801562
Ref: ec56801562
Ref: reference/datamodel object __pow__6801606
Ref: 7d76801606
Ref: reference/datamodel object __lshift__6801657
Ref: 21506801657
Ref: reference/datamodel object __rshift__6801701
Ref: 21516801701
Ref: reference/datamodel object __and__6801745
Ref: 21526801745
Ref: reference/datamodel object __xor__6801786
Ref: 21536801786
Ref: reference/datamodel object __or__6801827
Ref: 21546801827
Ref: reference/datamodel object __radd__6802780
Ref: 21466802780
Ref: reference/datamodel object __rsub__6802822
Ref: 21556802822
Ref: reference/datamodel object __rmul__6802864
Ref: 21496802864
Ref: reference/datamodel object __rmatmul__6802906
Ref: da86802906
Ref: reference/datamodel object __rtruediv__6802951
Ref: 21566802951
Ref: reference/datamodel object __rfloordiv__6802997
Ref: 21576802997
Ref: reference/datamodel object __rmod__6803044
Ref: e056803044
Ref: reference/datamodel object __rdivmod__6803086
Ref: 21586803086
Ref: reference/datamodel object __rpow__6803131
Ref: 7d86803131
Ref: reference/datamodel object __rlshift__6803183
Ref: 21596803183
Ref: reference/datamodel object __rrshift__6803228
Ref: 215a6803228
Ref: reference/datamodel object __rand__6803273
Ref: 215b6803273
Ref: reference/datamodel object __rxor__6803315
Ref: 215c6803315
Ref: reference/datamodel object __ror__6803357
Ref: 215d6803357
Ref: reference/datamodel object __iadd__6804624
Ref: 21476804624
Ref: reference/datamodel object __isub__6804666
Ref: 215e6804666
Ref: reference/datamodel object __imul__6804708
Ref: 214a6804708
Ref: reference/datamodel object __imatmul__6804750
Ref: da96804750
Ref: reference/datamodel object __itruediv__6804795
Ref: 215f6804795
Ref: reference/datamodel object __ifloordiv__6804841
Ref: 21606804841
Ref: reference/datamodel object __imod__6804888
Ref: 21616804888
Ref: reference/datamodel object __ipow__6804930
Ref: 7d56804930
Ref: reference/datamodel object __ilshift__6804982
Ref: 21626804982
Ref: reference/datamodel object __irshift__6805027
Ref: 21636805027
Ref: reference/datamodel object __iand__6805072
Ref: 21646805072
Ref: reference/datamodel object __ixor__6805114
Ref: 21656805114
Ref: reference/datamodel object __ior__6805156
Ref: 21666805156
Ref: reference/datamodel object __neg__6806348
Ref: 21686806348
Ref: reference/datamodel object __pos__6806382
Ref: 21696806382
Ref: reference/datamodel object __abs__6806416
Ref: 216a6806416
Ref: reference/datamodel object __invert__6806450
Ref: 216b6806450
Ref: reference/datamodel object __complex__6806603
Ref: 5ea6806603
Ref: reference/datamodel object __int__6806641
Ref: 71f6806641
Ref: reference/datamodel object __float__6806675
Ref: 9d76806675
Ref: reference/datamodel object __index__6806883
Ref: 7206806883
Ref: reference/datamodel object __round__6807555
Ref: 216c6807555
Ref: reference/datamodel object __trunc__6807602
Ref: 71e6807602
Ref: reference/datamodel object __floor__6807638
Ref: 216d6807638
Ref: reference/datamodel object __ceil__6807674
Ref: 216e6807674
Ref: Emulating numeric types-Footnote-16808380
Ref: Emulating numeric types-Footnote-26808700
Node: With Statement Context Managers6808925
Ref: reference/datamodel context-managers6809112
Ref: 20e46809112
Ref: reference/datamodel with-statement-context-managers6809112
Ref: 21706809112
Ref: reference/datamodel object __enter__6809958
Ref: 5cb6809958
Ref: reference/datamodel object __exit__6810208
Ref: 13496810208
Ref: With Statement Context Managers-Footnote-16811090
Node: Customizing positional arguments in class pattern matching6811132
Ref: reference/datamodel class-pattern-matching6811318
Ref: 21726811318
Ref: reference/datamodel customizing-positional-arguments-in-class-pattern-matching6811318
Ref: 21736811318
Ref: reference/datamodel object __match_args__6811749
Ref: 1a1c6811749
Ref: Customizing positional arguments in class pattern matching-Footnote-16812707
Node: Emulating buffer types6812749
Ref: reference/datamodel emulating-buffer-types6812925
Ref: 21746812925
Ref: reference/datamodel python-buffer-protocol6812925
Ref: 21756812925
Ref: reference/datamodel object __buffer__6813382
Ref: 4626813382
Ref: reference/datamodel object __release_buffer__6813850
Ref: 18046813850
Ref: Emulating buffer types-Footnote-16814589
Node: Special method lookup6814631
Ref: reference/datamodel special-lookup6814740
Ref: 21176814740
Ref: reference/datamodel special-method-lookup6814740
Ref: 21766814740
Node: Coroutines6817461
Ref: reference/datamodel coroutines6817547
Ref: 21776817547
Node: Awaitable Objects6817697
Ref: reference/datamodel awaitable-objects6817787
Ref: 21786817787
Ref: reference/datamodel object __await__6818226
Ref: da36818226
Ref: Awaitable Objects-Footnote-16819091
Node: Coroutine Objects6819133
Ref: reference/datamodel coroutine-objects6819254
Ref: 20b86819254
Ref: reference/datamodel id186819254
Ref: 21796819254
Ref: reference/datamodel coroutine send6820125
Ref: 217c6820125
Ref: reference/datamodel coroutine throw6820653
Ref: 4fa6820653
Ref: reference/datamodel coroutine close6821440
Ref: 217e6821440
Node: Asynchronous Iterators6822063
Ref: reference/datamodel async-iterators6822196
Ref: da56822196
Ref: reference/datamodel asynchronous-iterators6822196
Ref: 217f6822196
Ref: reference/datamodel object __aiter__6822489
Ref: c1c6822489
Ref: reference/datamodel object __anext__6822579
Ref: 16786822579
Node: Asynchronous Context Managers6823479
Ref: reference/datamodel async-context-managers6823586
Ref: 5ff6823586
Ref: reference/datamodel asynchronous-context-managers6823586
Ref: 21806823586
Ref: reference/datamodel object __aenter__6823960
Ref: 21816823960
Ref: reference/datamodel object __aexit__6824119
Ref: 17346824119
Node: Execution model6824597
Ref: reference/executionmodel doc6824723
Ref: 21826824723
Ref: reference/executionmodel execmodel6824723
Ref: 21836824723
Ref: reference/executionmodel execution-model6824723
Ref: 21846824723
Ref: reference/executionmodel translation-repo6824723
Ref: 21856824723
Node: Structure of a program6824853
Ref: reference/executionmodel prog-structure6824954
Ref: 21866824954
Ref: reference/executionmodel structure-of-a-program6824954
Ref: 21876824954
Node: Naming and binding6825996
Ref: reference/executionmodel naming6826119
Ref: 20a96826119
Ref: reference/executionmodel naming-and-binding6826119
Ref: 21886826119
Node: Binding of names6826343
Ref: reference/executionmodel bind-names6826442
Ref: 21896826442
Ref: reference/executionmodel binding-of-names6826442
Ref: 218a6826442
Node: Resolution of names6828214
Ref: reference/executionmodel resolution-of-names6828339
Ref: 218d6828339
Ref: reference/executionmodel resolve-names6828339
Ref: 218e6828339
Node: Annotation scopes6832208
Ref: reference/executionmodel annotation-scopes6832332
Ref: 1886832332
Ref: reference/executionmodel id16832332
Ref: 21906832332
Ref: Annotation scopes-Footnote-16834988
Ref: Annotation scopes-Footnote-26835030
Ref: Annotation scopes-Footnote-36835072
Node: Lazy evaluation6835114
Ref: reference/executionmodel id26835252
Ref: 21926835252
Ref: reference/executionmodel lazy-evaluation6835252
Ref: 45a6835252
Node: Builtins and restricted execution6836885
Ref: reference/executionmodel builtins-and-restricted-execution6837039
Ref: 21936837039
Ref: reference/executionmodel restrict-exec6837039
Ref: 21946837039
Node: Interaction with dynamic features6837879
Ref: reference/executionmodel dynamic-features6838009
Ref: 21956838009
Ref: reference/executionmodel interaction-with-dynamic-features6838009
Ref: 21966838009
Ref: Interaction with dynamic features-Footnote-16838790
Node: Exceptions<2>6838928
Ref: reference/executionmodel exceptions6839020
Ref: 21976839020
Ref: reference/executionmodel id46839020
Ref: 21986839020
Node: The import system6841203
Ref: reference/import doc6841330
Ref: 21996841330
Ref: reference/import importsystem6841330
Ref: 20c26841330
Ref: reference/import the-import-system6841330
Ref: 219a6841330
Ref: reference/import translation-repo6841330
Ref: 219b6841330
Ref: The import system-Footnote-16843954
Ref: The import system-Footnote-26843995
Ref: The import system-Footnote-36844037
Node: importlib<10>6844079
Ref: reference/import importlib6844166
Ref: 219d6844166
Node: Packages<2>6844536
Ref: reference/import packages6844641
Ref: 219e6844641
Node: Regular packages6846048
Ref: reference/import regular-packages6846139
Ref: 219f6846139
Node: Namespace packages6847351
Ref: reference/import namespace-packages6847442
Ref: 21a16847442
Ref: reference/import reference-namespace-package6847442
Ref: 21a26847442
Ref: Namespace packages-Footnote-16848819
Node: Searching6848861
Ref: reference/import searching6848960
Ref: 21a46848960
Node: The module cache6849785
Ref: reference/import the-module-cache6849875
Ref: 21a56849875
Node: Finders and loaders6851432
Ref: reference/import finders-and-loaders6851543
Ref: 21a66851543
Ref: reference/import id26851543
Ref: 21a76851543
Node: Import hooks6853287
Ref: reference/import import-hooks6853395
Ref: 21aa6853395
Node: The meta path6854268
Ref: reference/import the-meta-path6854348
Ref: 21ab6854348
Node: Loading6857556
Ref: reference/import loading6857665
Ref: 21ad6857665
Ref: Loading-Footnote-16860740
Node: Loaders6861114
Ref: reference/import loaders6861184
Ref: 21ae6861184
Node: Submodules6864414
Ref: reference/import submodules6864505
Ref: 21af6864505
Node: Module specs6865737
Ref: reference/import id46865851
Ref: 21b06865851
Ref: reference/import module-specs6865851
Ref: 20c86865851
Node: __path__ attributes on modules6866892
Ref: reference/import package-path-rules6867008
Ref: 20ca6867008
Ref: reference/import path-attributes-on-modules6867008
Ref: 21b36867008
Ref: __path__ attributes on modules-Footnote-16868342
Ref: __path__ attributes on modules-Footnote-26868384
Node: Module reprs6868426
Ref: reference/import module-reprs6868558
Ref: 21b46868558
Node: Cached bytecode invalidation6869972
Ref: reference/import cached-bytecode-invalidation6870065
Ref: 21b56870065
Ref: reference/import pyc-invalidation6870065
Ref: 5ef6870065
Node: The Path Based Finder6871414
Ref: reference/import the-path-based-finder6871550
Ref: 21b66871550
Node: Path entry finders6874058
Ref: reference/import path-entry-finders6874169
Ref: 21b86874169
Node: Path entry finder protocol6879042
Ref: reference/import path-entry-finder-protocol6879153
Ref: 21ba6879153
Node: Replacing the standard import system6881530
Ref: reference/import replacing-the-standard-import-system6881683
Ref: 21bb6881683
Node: Package Relative Imports6882560
Ref: reference/import package-relative-imports6882727
Ref: 21bc6882727
Ref: reference/import relativeimports6882727
Ref: 21bd6882727
Node: Special considerations for __main__6883930
Ref: reference/import import-dunder-main6884071
Ref: 21be6884071
Ref: reference/import special-considerations-for-main6884071
Ref: 21bf6884071
Node: __main__ __spec__6884674
Ref: reference/import id56884763
Ref: 21c06884763
Ref: reference/import main-spec6884763
Ref: 21b26884763
Node: References6886160
Ref: reference/import references6886268
Ref: 21c16886268
Ref: References-Footnote-16887499
Ref: References-Footnote-26887551
Ref: References-Footnote-36887593
Ref: References-Footnote-46887635
Ref: References-Footnote-56887677
Ref: References-Footnote-66887719
Ref: References-Footnote-76887761
Ref: References-Footnote-86887803
Ref: References-Footnote-96887845
Ref: References-Footnote-106887887
Node: Expressions6887930
Ref: reference/expressions doc6888059
Ref: 21c26888059
Ref: reference/expressions expressions6888059
Ref: 21c36888059
Ref: reference/expressions id16888059
Ref: 21c46888059
Ref: reference/expressions translation-repo6888059
Ref: 21c56888059
Ref: reference/expressions grammar-token-python-grammar-name6888353
Ref: 21c66888353
Node: Arithmetic conversions6888919
Ref: reference/expressions arithmetic-conversions6889003
Ref: 21c76889003
Ref: reference/expressions conversions6889003
Ref: 21c86889003
Node: Atoms6889706
Ref: reference/expressions atoms6889808
Ref: 21c96889808
Ref: reference/expressions id26889808
Ref: 21ca6889808
Ref: reference/expressions grammar-token-python-grammar-atom6890055
Ref: 21cb6890055
Ref: reference/expressions grammar-token-python-grammar-enclosure6890146
Ref: 21cd6890146
Node: Identifiers Names6890651
Ref: reference/expressions atom-identifiers6890730
Ref: 204c6890730
Ref: reference/expressions identifiers-names6890730
Ref: 21d46890730
Ref: reference/expressions private-name-mangling6891169
Ref: 1e5b6891169
Node: Private name mangling6891205
Ref: reference/expressions id36891280
Ref: 21d56891280
Node: Literals<2>6893065
Ref: reference/expressions atom-literals6893172
Ref: 21d66893172
Ref: reference/expressions literals6893172
Ref: 21d76893172
Ref: reference/expressions grammar-token-python-grammar-literal6893280
Ref: 21cc6893280
Node: Parenthesized forms6894052
Ref: reference/expressions parenthesized6894182
Ref: 21d86894182
Ref: reference/expressions parenthesized-forms6894182
Ref: 21d96894182
Ref: reference/expressions grammar-token-python-grammar-parenth_form6894317
Ref: 21ce6894317
Node: Displays for lists sets and dictionaries6895085
Ref: reference/expressions comprehensions6895217
Ref: 5d36895217
Ref: reference/expressions displays-for-lists-sets-and-dictionaries6895217
Ref: 21db6895217
Ref: reference/expressions grammar-token-python-grammar-comprehension6895663
Ref: 21dc6895663
Ref: reference/expressions grammar-token-python-grammar-comp_for6895743
Ref: 21dd6895743
Ref: reference/expressions grammar-token-python-grammar-comp_iter6895858
Ref: 21e06895858
Ref: reference/expressions grammar-token-python-grammar-comp_if6895926
Ref: 21e16895926
Ref: Displays for lists sets and dictionaries-Footnote-16898428
Node: List displays6898470
Ref: reference/expressions list-displays6898595
Ref: 21e26898595
Ref: reference/expressions lists6898595
Ref: 21e36898595
Ref: reference/expressions grammar-token-python-grammar-list_display6898727
Ref: 21cf6898727
Node: Set displays6899211
Ref: reference/expressions set6899315
Ref: 21e56899315
Ref: reference/expressions set-displays6899315
Ref: 21e66899315
Ref: reference/expressions grammar-token-python-grammar-set_display6899495
Ref: 21d16899495
Node: Dictionary displays6900065
Ref: reference/expressions dict6900177
Ref: dad6900177
Ref: reference/expressions dictionary-displays6900177
Ref: 21e76900177
Ref: reference/expressions grammar-token-python-grammar-dict_display6900341
Ref: 21d06900341
Ref: reference/expressions grammar-token-python-grammar-dict_item_list6900441
Ref: 21e86900441
Ref: reference/expressions grammar-token-python-grammar-dict_item6900528
Ref: 21ea6900528
Ref: reference/expressions grammar-token-python-grammar-dict_comprehension6900636
Ref: 21e96900636
Ref: Dictionary displays-Footnote-16902481
Ref: Dictionary displays-Footnote-26902523
Node: Generator expressions6902565
Ref: reference/expressions generator-expressions6902682
Ref: 21ec6902682
Ref: reference/expressions genexpr6902682
Ref: 21ed6902682
Ref: reference/expressions grammar-token-python-grammar-generator_expression6902815
Ref: 21d26902815
Node: Yield expressions6904879
Ref: reference/expressions yield-expressions6904968
Ref: 21ee6904968
Ref: reference/expressions yieldexpr6904968
Ref: 21ef6904968
Ref: reference/expressions grammar-token-python-grammar-yield_atom6905023
Ref: 21d36905023
Ref: reference/expressions grammar-token-python-grammar-yield_from6905087
Ref: 21f06905087
Ref: reference/expressions grammar-token-python-grammar-yield_expression6905152
Ref: 20706905152
Ref: Yield expressions-Footnote-16910128
Ref: Yield expressions-Footnote-26910170
Ref: Yield expressions-Footnote-36910212
Ref: Yield expressions-Footnote-46910254
Ref: Yield expressions-Footnote-56910296
Node: Generator-iterator methods6910338
Ref: reference/expressions generator-iterator-methods6910435
Ref: 21f46910435
Ref: reference/expressions generator-methods6910435
Ref: 217b6910435
Ref: reference/expressions generator __next__6910777
Ref: 1e666910777
Ref: reference/expressions generator send6911516
Ref: 217d6911516
Ref: reference/expressions generator throw6912084
Ref: 4fb6912084
Ref: reference/expressions generator close6913376
Ref: 15df6913376
Node: Examples6914369
Ref: reference/expressions examples6914510
Ref: 21f56914510
Node: Asynchronous generator functions<2>6915570
Ref: reference/expressions asynchronous-generator-functions6915724
Ref: 21f36915724
Ref: reference/expressions id46915724
Ref: 21f66915724
Ref: Asynchronous generator functions<2>-Footnote-16919395
Node: Asynchronous generator-iterator methods6919475
Ref: reference/expressions asynchronous-generator-iterator-methods6919612
Ref: 21f86919612
Ref: reference/expressions asynchronous-generator-methods6919612
Ref: 21f96919612
Ref: reference/expressions agen __anext__6919854
Ref: 21f76919854
Ref: reference/expressions agen asend6920769
Ref: 8e26920769
Ref: reference/expressions agen athrow6921616
Ref: 4fc6921616
Ref: reference/expressions agen aclose6922494
Ref: 8e16922494
Node: Primaries6923487
Ref: reference/expressions id56923583
Ref: 21fa6923583
Ref: reference/expressions primaries6923583
Ref: 21fb6923583
Ref: reference/expressions grammar-token-python-grammar-primary6923705
Ref: 21fc6923705
Node: Attribute references6923916
Ref: reference/expressions attribute-references6924004
Ref: 22016924004
Ref: reference/expressions id66924004
Ref: 22026924004
Ref: reference/expressions grammar-token-python-grammar-attributeref6924133
Ref: 21fd6924133
Node: Subscriptions6924950
Ref: reference/expressions id76925055
Ref: 22036925055
Ref: reference/expressions subscriptions6925055
Ref: 21346925055
Ref: reference/expressions grammar-token-python-grammar-subscription6925326
Ref: 21fe6925326
Ref: Subscriptions-Footnote-16927985
Node: Slicings6928027
Ref: reference/expressions id86928117
Ref: 22046928117
Ref: reference/expressions slicings6928117
Ref: 22056928117
Ref: reference/expressions grammar-token-python-grammar-slicing6928366
Ref: 21ff6928366
Ref: reference/expressions grammar-token-python-grammar-slice_list6928441
Ref: 22066928441
Ref: reference/expressions grammar-token-python-grammar-slice_item6928524
Ref: 22076928524
Ref: reference/expressions grammar-token-python-grammar-proper_slice6928598
Ref: 22086928598
Ref: reference/expressions grammar-token-python-grammar-lower_bound6928708
Ref: 22096928708
Ref: reference/expressions grammar-token-python-grammar-upper_bound6928754
Ref: 220a6928754
Ref: reference/expressions grammar-token-python-grammar-stride6928800
Ref: 220b6928800
Node: Calls6930051
Ref: reference/expressions calls6930119
Ref: dab6930119
Ref: reference/expressions id96930119
Ref: 220c6930119
Ref: reference/expressions grammar-token-python-grammar-call6930267
Ref: 22006930267
Ref: reference/expressions grammar-token-python-grammar-argument_list6930390
Ref: 220e6930390
Ref: reference/expressions grammar-token-python-grammar-positional_arguments6930730
Ref: 220f6930730
Ref: reference/expressions grammar-token-python-grammar-positional_item6930825
Ref: 22126930825
Ref: reference/expressions grammar-token-python-grammar-starred_and_keywords6930920
Ref: 22106930920
Ref: reference/expressions grammar-token-python-grammar-keywords_arguments6931105
Ref: 22116931105
Ref: reference/expressions grammar-token-python-grammar-keyword_item6931292
Ref: 22136931292
Ref: Calls-Footnote-16938052
Node: Await expression6938094
Ref: reference/expressions await6938203
Ref: 1b96938203
Ref: reference/expressions await-expression6938203
Ref: 22146938203
Ref: reference/expressions grammar-token-python-grammar-await_expr6938392
Ref: 22156938392
Node: The power operator6938465
Ref: reference/expressions power6938604
Ref: 22166938604
Ref: reference/expressions the-power-operator6938604
Ref: 22176938604
Ref: reference/expressions grammar-token-python-grammar-power6938801
Ref: 22186938801
Node: Unary arithmetic and bitwise operations6939999
Ref: reference/expressions unary6940150
Ref: 221a6940150
Ref: reference/expressions unary-arithmetic-and-bitwise-operations6940150
Ref: 221b6940150
Ref: reference/expressions grammar-token-python-grammar-u_expr6940312
Ref: 22196940312
Node: Binary arithmetic operations6941124
Ref: reference/expressions binary6941276
Ref: 221c6941276
Ref: reference/expressions binary-arithmetic-operations6941276
Ref: 221d6941276
Ref: reference/expressions grammar-token-python-grammar-m_expr6941620
Ref: 221e6941620
Ref: reference/expressions grammar-token-python-grammar-a_expr6941919
Ref: 221f6941919
Ref: Binary arithmetic operations-Footnote-16945674
Ref: Binary arithmetic operations-Footnote-26946287
Node: Shifting operations6946570
Ref: reference/expressions shifting6946708
Ref: 22216946708
Ref: reference/expressions shifting-operations6946708
Ref: 22226946708
Ref: reference/expressions grammar-token-python-grammar-shift_expr6946838
Ref: 22236946838
Node: Binary bitwise operations6947498
Ref: reference/expressions binary-bitwise-operations6947619
Ref: 22246947619
Ref: reference/expressions bitwise6947619
Ref: 22256947619
Ref: reference/expressions grammar-token-python-grammar-and_expr6947754
Ref: 22266947754
Ref: reference/expressions grammar-token-python-grammar-xor_expr6947848
Ref: 22276947848
Ref: reference/expressions grammar-token-python-grammar-or_expr6947938
Ref: 206f6947938
Node: Comparisons6948661
Ref: reference/expressions comparisons6948781
Ref: 22286948781
Ref: reference/expressions id126948781
Ref: 22296948781
Ref: reference/expressions grammar-token-python-grammar-comparison6949076
Ref: 222a6949076
Ref: reference/expressions grammar-token-python-grammar-comp_operator6949171
Ref: 222b6949171
Node: Value comparisons6950261
Ref: reference/expressions expressions-value-comparisons6950361
Ref: 19c46950361
Ref: reference/expressions value-comparisons6950361
Ref: 222c6950361
Ref: reference/expressions in6958212
Ref: 2f46958212
Ref: reference/expressions not-in6958212
Ref: 6326958212
Ref: Value comparisons-Footnote-16958250
Ref: Value comparisons-Footnote-26958292
Node: Membership test operations6959401
Ref: reference/expressions membership-test-details6959530
Ref: 214b6959530
Ref: reference/expressions membership-test-operations6959530
Ref: 222d6959530
Ref: reference/expressions is6961423
Ref: 2f56961423
Node: Identity comparisons6961423
Ref: reference/expressions identity-comparisons6961526
Ref: 222e6961526
Ref: reference/expressions is-not6961526
Ref: 222f6961526
Ref: reference/expressions booleans6961872
Ref: 22306961872
Ref: reference/expressions and6961872
Ref: 2f16961872
Ref: reference/expressions or6961872
Ref: 2f66961872
Ref: Identity comparisons-Footnote-16961910
Node: Boolean operations6962212
Ref: reference/expressions boolean-operations6962332
Ref: 22316962332
Ref: reference/expressions not6962332
Ref: 22326962332
Ref: reference/expressions grammar-token-python-grammar-or_test6962385
Ref: 21df6962385
Ref: reference/expressions grammar-token-python-grammar-and_test6962475
Ref: 22336962475
Ref: reference/expressions grammar-token-python-grammar-not_test6962567
Ref: 22346962567
Node: Assignment expressions<2>6964035
Ref: reference/expressions assignment-expressions6964167
Ref: 22356964167
Ref: reference/expressions id156964167
Ref: 22366964167
Ref: reference/expressions grammar-token-python-grammar-assignment_expression6964228
Ref: 21916964228
Ref: Assignment expressions<2>-Footnote-16965299
Node: Conditional expressions6965341
Ref: reference/expressions conditional-expressions6965462
Ref: 22376965462
Ref: reference/expressions if-expr6965462
Ref: 22386965462
Ref: reference/expressions grammar-token-python-grammar-conditional_expression6965525
Ref: 206e6965525
Ref: reference/expressions grammar-token-python-grammar-expression6965637
Ref: 21eb6965637
Ref: reference/expressions lambdas6966193
Ref: 223a6966193
Ref: Conditional expressions-Footnote-16966231
Node: Lambdas6966273
Ref: reference/expressions id166966385
Ref: 223b6966385
Ref: reference/expressions lambda6966385
Ref: 12e46966385
Ref: reference/expressions grammar-token-python-grammar-lambda_expr6966416
Ref: 22396966416
Node: Expression lists6966976
Ref: reference/expressions expression-lists6967081
Ref: 223d6967081
Ref: reference/expressions exprlists6967081
Ref: dac6967081
Ref: reference/expressions grammar-token-python-grammar-starred_expression6967130
Ref: 21da6967130
Ref: reference/expressions grammar-token-python-grammar-flexible_expression6967191
Ref: 223e6967191
Ref: reference/expressions grammar-token-python-grammar-flexible_expression_list6967294
Ref: 21e46967294
Ref: reference/expressions grammar-token-python-grammar-starred_expression_list6967407
Ref: 223f6967407
Ref: reference/expressions grammar-token-python-grammar-expression_list6967518
Ref: 22406967518
Ref: reference/expressions grammar-token-python-grammar-yield_list6967613
Ref: 21f16967613
Ref: Expression lists-Footnote-16968741
Ref: Expression lists-Footnote-26968783
Node: Evaluation order6968825
Ref: reference/expressions evalorder6968942
Ref: 22416968942
Ref: reference/expressions evaluation-order6968942
Ref: 22426968942
Node: Operator precedence6969457
Ref: reference/expressions operator-precedence6969549
Ref: 22436969549
Ref: reference/expressions operator-summary6969549
Ref: 22446969549
Ref: Operator precedence-Footnote-16974067
Ref: Operator precedence-Footnote-26974216
Node: Simple statements6974310
Ref: reference/simple_stmts doc6974441
Ref: 22456974441
Ref: reference/simple_stmts simple6974441
Ref: 22466974441
Ref: reference/simple_stmts simple-statements6974441
Ref: 22476974441
Ref: reference/simple_stmts translation-repo6974441
Ref: 22486974441
Ref: reference/simple_stmts grammar-token-python-grammar-simple_stmt6974665
Ref: 22496974665
Node: Expression statements6975887
Ref: reference/simple_stmts expression-statements6975992
Ref: 225b6975992
Ref: reference/simple_stmts exprstmts6975992
Ref: 225c6975992
Ref: reference/simple_stmts grammar-token-python-grammar-expression_stmt6976382
Ref: 224a6976382
Node: Assignment statements6976822
Ref: reference/simple_stmts assignment6976956
Ref: 218b6976956
Ref: reference/simple_stmts assignment-statements6976956
Ref: 225d6976956
Ref: reference/simple_stmts grammar-token-python-grammar-assignment_stmt6977127
Ref: 224c6977127
Ref: reference/simple_stmts grammar-token-python-grammar-target_list6977250
Ref: 21de6977250
Ref: reference/simple_stmts grammar-token-python-grammar-target6977328
Ref: 225e6977328
Ref: reference/simple_stmts attr-target-note6980871
Ref: 225f6980871
Ref: Assignment statements-Footnote-16984935
Node: Augmented assignment statements6984977
Ref: reference/simple_stmts augassign6985106
Ref: 22606985106
Ref: reference/simple_stmts augmented-assignment-statements6985106
Ref: 22616985106
Ref: reference/simple_stmts grammar-token-python-grammar-augmented_assignment_stmt6985303
Ref: 224d6985303
Ref: reference/simple_stmts grammar-token-python-grammar-augtarget6985443
Ref: 22626985443
Ref: reference/simple_stmts grammar-token-python-grammar-augop6985581
Ref: 22636985581
Node: Annotated assignment statements6987322
Ref: reference/simple_stmts annassign6987451
Ref: 22646987451
Ref: reference/simple_stmts annotated-assignment-statements6987451
Ref: 22656987451
Ref: reference/simple_stmts grammar-token-python-grammar-annotated_assignment_stmt6987686
Ref: 224e6987686
Ref: Annotated assignment statements-Footnote-16989852
Ref: Annotated assignment statements-Footnote-26989894
Node: The assert statement6989936
Ref: reference/simple_stmts assert6990067
Ref: 9726990067
Ref: reference/simple_stmts the-assert-statement6990067
Ref: 22666990067
Ref: reference/simple_stmts grammar-token-python-grammar-assert_stmt6990217
Ref: 224b6990217
Node: The pass statement6991332
Ref: reference/simple_stmts pass6991462
Ref: 1db16991462
Ref: reference/simple_stmts the-pass-statement6991462
Ref: 22676991462
Ref: reference/simple_stmts grammar-token-python-grammar-pass_stmt6991521
Ref: 224f6991521
Node: The del statement<2>6991872
Ref: reference/simple_stmts del6992002
Ref: 18c26992002
Ref: reference/simple_stmts the-del-statement6992002
Ref: 22686992002
Ref: reference/simple_stmts grammar-token-python-grammar-del_stmt6992059
Ref: 22506992059
Node: The return statement6992993
Ref: reference/simple_stmts return6993124
Ref: 9d96993124
Ref: reference/simple_stmts the-return-statement6993124
Ref: 22696993124
Ref: reference/simple_stmts grammar-token-python-grammar-return_stmt6993187
Ref: 22516993187
Node: The yield statement6994326
Ref: reference/simple_stmts the-yield-statement6994456
Ref: 226a6994456
Ref: reference/simple_stmts yield6994456
Ref: 9d86994456
Ref: reference/simple_stmts grammar-token-python-grammar-yield_stmt6994517
Ref: 22526994517
Node: The raise statement6995384
Ref: reference/simple_stmts raise6995513
Ref: 5f06995513
Ref: reference/simple_stmts the-raise-statement6995513
Ref: 226b6995513
Ref: reference/simple_stmts grammar-token-python-grammar-raise_stmt6995574
Ref: 22536995574
Node: The break statement6999807
Ref: reference/simple_stmts break6999939
Ref: abe6999939
Ref: reference/simple_stmts the-break-statement6999939
Ref: 226e6999939
Ref: reference/simple_stmts grammar-token-python-grammar-break_stmt7000000
Ref: 22547000000
Node: The continue statement7000594
Ref: reference/simple_stmts continue7000727
Ref: 9d47000727
Ref: reference/simple_stmts the-continue-statement7000727
Ref: 226f7000727
Ref: reference/simple_stmts grammar-token-python-grammar-continue_stmt7000796
Ref: 22557000796
Ref: reference/simple_stmts import7001262
Ref: 5e57001262
Node: The import statement7001264
Ref: reference/simple_stmts from7001398
Ref: 12f37001398
Ref: reference/simple_stmts the-import-statement7001398
Ref: 22707001398
Ref: reference/simple_stmts grammar-token-python-grammar-import_stmt7001463
Ref: 22567001463
Ref: reference/simple_stmts grammar-token-python-grammar-module7002124
Ref: 22717002124
Ref: reference/simple_stmts grammar-token-python-grammar-relative_module7002204
Ref: 22727002204
Ref: reference/simple_stmts module __all__7005373
Ref: d687005373
Ref: The import statement-Footnote-17007661
Node: Future statements7007718
Ref: reference/simple_stmts future7007792
Ref: 1897007792
Ref: reference/simple_stmts future-statements7007792
Ref: 22737007792
Ref: reference/simple_stmts grammar-token-python-grammar-future_stmt7008318
Ref: 22577008318
Ref: reference/simple_stmts grammar-token-python-grammar-feature7008698
Ref: 22747008698
Ref: Future statements-Footnote-17011423
Ref: Future statements-Footnote-27011465
Node: The global statement7011507
Ref: reference/simple_stmts global7011641
Ref: 18a7011641
Ref: reference/simple_stmts the-global-statement7011641
Ref: 22757011641
Ref: reference/simple_stmts grammar-token-python-grammar-global_stmt7011706
Ref: 22587011706
Node: The nonlocal statement7013079
Ref: reference/simple_stmts nonlocal7013211
Ref: 12ef7013211
Ref: reference/simple_stmts the-nonlocal-statement7013211
Ref: 22767013211
Ref: reference/simple_stmts grammar-token-python-grammar-nonlocal_stmt7013280
Ref: 22597013280
Ref: The nonlocal statement-Footnote-17014492
Node: The type statement7014534
Ref: reference/simple_stmts the-type-statement7014637
Ref: 22777014637
Ref: reference/simple_stmts type7014637
Ref: 43b7014637
Ref: reference/simple_stmts grammar-token-python-grammar-type_stmt7014698
Ref: 225a7014698
Ref: The type statement-Footnote-17016028
Node: Compound statements7016070
Ref: reference/compound_stmts doc7016210
Ref: 22797016210
Ref: reference/compound_stmts compound7016210
Ref: 227a7016210
Ref: reference/compound_stmts compound-statements7016210
Ref: 227b7016210
Ref: reference/compound_stmts translation-repo7016210
Ref: 227c7016210
Ref: reference/compound_stmts grammar-token-python-grammar-compound_stmt7017979
Ref: 227d7017979
Ref: reference/compound_stmts grammar-token-python-grammar-suite7018515
Ref: 22897018515
Ref: reference/compound_stmts grammar-token-python-grammar-statement7018617
Ref: 228b7018617
Ref: reference/compound_stmts grammar-token-python-grammar-stmt_list7018700
Ref: 228a7018700
Ref: reference/compound_stmts if7019251
Ref: 2f37019251
Ref: reference/compound_stmts elif7019251
Ref: 1da17019251
Node: The if statement7019499
Ref: reference/compound_stmts else7019599
Ref: 18c7019599
Ref: reference/compound_stmts the-if-statement7019599
Ref: 228c7019599
Ref: reference/compound_stmts grammar-token-python-grammar-if_stmt7019719
Ref: 227e7019719
Node: The while statement7020331
Ref: reference/compound_stmts the-while-statement7020457
Ref: 228d7020457
Ref: reference/compound_stmts while7020457
Ref: 1d9a7020457
Ref: reference/compound_stmts grammar-token-python-grammar-while_stmt7020617
Ref: 227f7020617
Node: The for statement7021256
Ref: reference/compound_stmts for7021383
Ref: 2f27021383
Ref: reference/compound_stmts the-for-statement7021383
Ref: 228e7021383
Ref: reference/compound_stmts grammar-token-python-grammar-for_stmt7021582
Ref: 22807021582
Node: The try statement7023378
Ref: reference/compound_stmts the-try-statement7023504
Ref: 228f7023504
Ref: reference/compound_stmts try7023504
Ref: 6ec7023504
Ref: reference/compound_stmts grammar-token-python-grammar-try_stmt7023662
Ref: 22817023662
Ref: reference/compound_stmts grammar-token-python-grammar-try1_stmt7023754
Ref: 22907023754
Ref: reference/compound_stmts grammar-token-python-grammar-try2_stmt7024018
Ref: 22917024018
Ref: reference/compound_stmts grammar-token-python-grammar-try3_stmt7024284
Ref: 22927024284
Node: except clause7024689
Ref: reference/compound_stmts except7024779
Ref: 18b7024779
Ref: reference/compound_stmts except-clause7024779
Ref: 22937024779
Ref: except clause-Footnote-17028024
Node: except* clause7028222
Ref: reference/compound_stmts except-star7028332
Ref: 5bb7028332
Ref: reference/compound_stmts id27028332
Ref: 22947028332
Node: else clause7031342
Ref: reference/compound_stmts else-clause7031453
Ref: 22957031453
Ref: reference/compound_stmts except-else7031453
Ref: 22967031453
Node: finally clause7031814
Ref: reference/compound_stmts finally7031902
Ref: 9d57031902
Ref: reference/compound_stmts finally-clause7031902
Ref: 22977031902
Ref: reference/compound_stmts with7033662
Ref: 5d57033662
Node: The with statement7033662
Ref: reference/compound_stmts as7033790
Ref: 22987033790
Ref: reference/compound_stmts the-with-statement7033790
Ref: 22997033790
Ref: reference/compound_stmts grammar-token-python-grammar-with_stmt7034159
Ref: 22827034159
Ref: reference/compound_stmts grammar-token-python-grammar-with_stmt_contents7034300
Ref: 229a7034300
Ref: reference/compound_stmts grammar-token-python-grammar-with_item7034381
Ref: 229b7034381
Ref: reference/compound_stmts match7037660
Ref: 8137037660
Ref: The with statement-Footnote-17037696
Node: The match statement7037738
Ref: reference/compound_stmts case7037869
Ref: 229c7037869
Ref: reference/compound_stmts the-match-statement7037869
Ref: 229d7037869
Ref: reference/compound_stmts grammar-token-python-grammar-match_stmt7038014
Ref: 22837038014
Ref: reference/compound_stmts grammar-token-python-grammar-subject_expr7038121
Ref: 229e7038121
Ref: reference/compound_stmts grammar-token-python-grammar-case_block7038243
Ref: 229f7038243
Ref: The match statement-Footnote-17039147
Ref: The match statement-Footnote-27039189
Node: Overview7039231
Ref: reference/compound_stmts overview7039310
Ref: 22a27039310
Node: Guards7041782
Ref: reference/compound_stmts guards7041893
Ref: 22a47041893
Ref: reference/compound_stmts grammar-token-python-grammar-guard7041924
Ref: 22a17041924
Node: Irrefutable Case Blocks7043058
Ref: reference/compound_stmts irrefutable-case7043169
Ref: 22a57043169
Ref: reference/compound_stmts irrefutable-case-blocks7043169
Ref: 22a67043169
Node: Patterns7043874
Ref: reference/compound_stmts patterns7043970
Ref: 22aa7043970
Ref: reference/compound_stmts grammar-token-python-grammar-patterns7044294
Ref: 22a07044294
Ref: reference/compound_stmts grammar-token-python-grammar-pattern7044376
Ref: 22ac7044376
Ref: reference/compound_stmts grammar-token-python-grammar-closed_pattern7044450
Ref: 22af7044450
Node: OR Patterns7045470
Ref: reference/compound_stmts id37045546
Ref: 22b87045546
Ref: reference/compound_stmts or-patterns7045546
Ref: 22a87045546
Ref: reference/compound_stmts grammar-token-python-grammar-or_pattern7045670
Ref: 22ae7045670
Node: AS Patterns7046237
Ref: reference/compound_stmts as-patterns7046338
Ref: 22a77046338
Ref: reference/compound_stmts id47046338
Ref: 22b97046338
Ref: reference/compound_stmts grammar-token-python-grammar-as_pattern7046487
Ref: 22ad7046487
Node: Literal Patterns7046869
Ref: reference/compound_stmts id57046975
Ref: 22ba7046975
Ref: reference/compound_stmts literal-patterns7046975
Ref: 22bb7046975
Ref: reference/compound_stmts grammar-token-python-grammar-literal_pattern7047106
Ref: 22b07047106
Ref: reference/compound_stmts grammar-token-python-grammar-signed_number7047429
Ref: 22bc7047429
Node: Capture Patterns7048100
Ref: reference/compound_stmts capture-patterns7048212
Ref: 22a97048212
Ref: reference/compound_stmts id67048212
Ref: 22be7048212
Ref: reference/compound_stmts grammar-token-python-grammar-capture_pattern7048326
Ref: 22b17048326
Ref: Capture Patterns-Footnote-17049069
Node: Wildcard Patterns7049111
Ref: reference/compound_stmts id77049221
Ref: 22bf7049221
Ref: reference/compound_stmts wildcard-patterns7049221
Ref: 8147049221
Ref: reference/compound_stmts grammar-token-python-grammar-wildcard_pattern7049356
Ref: 22b27049356
Node: Value Patterns7049633
Ref: reference/compound_stmts id87049741
Ref: 22c07049741
Ref: reference/compound_stmts value-patterns7049741
Ref: 22c17049741
Ref: reference/compound_stmts grammar-token-python-grammar-value_pattern7049852
Ref: 22b37049852
Ref: reference/compound_stmts grammar-token-python-grammar-attr7049893
Ref: 22c27049893
Ref: reference/compound_stmts grammar-token-python-grammar-name_or_attr7049951
Ref: 22c37049951
Node: Group Patterns7050577
Ref: reference/compound_stmts group-patterns7050685
Ref: 22c47050685
Ref: reference/compound_stmts id97050685
Ref: 22c57050685
Ref: reference/compound_stmts grammar-token-python-grammar-group_pattern7050885
Ref: 22b47050885
Node: Sequence Patterns7050997
Ref: reference/compound_stmts id107051107
Ref: 22c67051107
Ref: reference/compound_stmts sequence-patterns7051107
Ref: 22c77051107
Ref: reference/compound_stmts grammar-token-python-grammar-sequence_pattern7051312
Ref: 22b57051312
Ref: reference/compound_stmts grammar-token-python-grammar-open_sequence_pattern7051469
Ref: 22ab7051469
Ref: reference/compound_stmts grammar-token-python-grammar-maybe_sequence_pattern7051575
Ref: 22c87051575
Ref: reference/compound_stmts grammar-token-python-grammar-maybe_star_pattern7051649
Ref: 22c97051649
Ref: reference/compound_stmts grammar-token-python-grammar-star_pattern7051730
Ref: 22ca7051730
Ref: Sequence Patterns-Footnote-17054753
Node: Mapping Patterns7055470
Ref: reference/compound_stmts id127055580
Ref: 22cb7055580
Ref: reference/compound_stmts mapping-patterns7055580
Ref: 22cc7055580
Ref: reference/compound_stmts grammar-token-python-grammar-mapping_pattern7055762
Ref: 22b67055762
Ref: reference/compound_stmts grammar-token-python-grammar-items_pattern7055828
Ref: 22cd7055828
Ref: reference/compound_stmts grammar-token-python-grammar-key_value_pattern7055898
Ref: 22ce7055898
Ref: reference/compound_stmts grammar-token-python-grammar-double_star_pattern7056076
Ref: 22cf7056076
Ref: Mapping Patterns-Footnote-17057690
Node: Class Patterns7058164
Ref: reference/compound_stmts class-patterns7058248
Ref: 22d07058248
Ref: reference/compound_stmts id147058248
Ref: 22d17058248
Ref: reference/compound_stmts grammar-token-python-grammar-class_pattern7058393
Ref: 22b77058393
Ref: reference/compound_stmts grammar-token-python-grammar-pattern_arguments7058494
Ref: 22d27058494
Ref: reference/compound_stmts grammar-token-python-grammar-positional_patterns7058653
Ref: 22d37058653
Ref: reference/compound_stmts grammar-token-python-grammar-keyword_patterns7058708
Ref: 22d47058708
Ref: reference/compound_stmts grammar-token-python-grammar-keyword_pattern7058771
Ref: 22d57058771
Ref: reference/compound_stmts function7062836
Ref: 1dce7062836
Ref: Class Patterns-Footnote-17062872
Ref: Class Patterns-Footnote-27062914
Node: Function definitions7062956
Ref: reference/compound_stmts def7063086
Ref: 14a97063086
Ref: reference/compound_stmts function-definitions7063086
Ref: 22d67063086
Ref: reference/compound_stmts grammar-token-python-grammar-funcdef7063259
Ref: 22847063259
Ref: reference/compound_stmts grammar-token-python-grammar-decorators7063502
Ref: 22d77063502
Ref: reference/compound_stmts grammar-token-python-grammar-decorator7063561
Ref: 22d97063561
Ref: reference/compound_stmts grammar-token-python-grammar-parameter_list7063643
Ref: 223c7063643
Ref: reference/compound_stmts grammar-token-python-grammar-parameter_list_no_posonly7063868
Ref: 22db7063868
Ref: reference/compound_stmts grammar-token-python-grammar-parameter_list_starargs7064081
Ref: 22dc7064081
Ref: reference/compound_stmts grammar-token-python-grammar-parameter_star_kwargs7064415
Ref: 22de7064415
Ref: reference/compound_stmts grammar-token-python-grammar-parameter7064484
Ref: 22df7064484
Ref: reference/compound_stmts grammar-token-python-grammar-star_parameter7064573
Ref: 22dd7064573
Ref: reference/compound_stmts grammar-token-python-grammar-defparameter7064668
Ref: 22da7064668
Ref: reference/compound_stmts grammar-token-python-grammar-funcname7064756
Ref: 22d87064756
Ref: Function definitions-Footnote-17071781
Ref: Function definitions-Footnote-27071982
Ref: Function definitions-Footnote-37072024
Ref: Function definitions-Footnote-47072066
Ref: Function definitions-Footnote-57072108
Ref: Function definitions-Footnote-67072150
Ref: Function definitions-Footnote-77072192
Ref: Function definitions-Footnote-87072234
Ref: Function definitions-Footnote-97072276
Ref: Function definitions-Footnote-107072318
Node: Class definitions7072361
Ref: reference/compound_stmts class7072485
Ref: 131f7072485
Ref: reference/compound_stmts class-definitions7072485
Ref: 22e17072485
Ref: reference/compound_stmts grammar-token-python-grammar-classdef7072633
Ref: 22857072633
Ref: reference/compound_stmts grammar-token-python-grammar-inheritance7072788
Ref: 22e37072788
Ref: reference/compound_stmts grammar-token-python-grammar-classname7072846
Ref: 22e27072846
Ref: Class definitions-Footnote-17076160
Ref: Class definitions-Footnote-27076351
Ref: Class definitions-Footnote-37076393
Ref: Class definitions-Footnote-47076435
Ref: Class definitions-Footnote-57076477
Node: Coroutines<2>7076519
Ref: reference/compound_stmts async7076643
Ref: 7357076643
Ref: reference/compound_stmts coroutines7076643
Ref: 22e47076643
Node: Coroutine function definition7076802
Ref: reference/compound_stmts async-def7076913
Ref: 5d47076913
Ref: reference/compound_stmts coroutine-function-definition7076913
Ref: 22e57076913
Ref: reference/compound_stmts grammar-token-python-grammar-async_funcdef7076990
Ref: 22887076990
Node: The async for statement7077967
Ref: reference/compound_stmts async-for7078111
Ref: ac07078111
Ref: reference/compound_stmts the-async-for-statement7078111
Ref: 22e67078111
Ref: reference/compound_stmts grammar-token-python-grammar-async_for_stmt7078184
Ref: 22877078184
Node: The async with statement7079141
Ref: reference/compound_stmts async-with7079247
Ref: 5d87079247
Ref: reference/compound_stmts the-async-with-statement7079247
Ref: 22e77079247
Ref: reference/compound_stmts grammar-token-python-grammar-async_with_stmt7079322
Ref: 22867079322
Ref: The async with statement-Footnote-17080475
Node: Type parameter lists7080517
Ref: reference/compound_stmts type-parameter-lists7080615
Ref: 22e87080615
Ref: reference/compound_stmts type-params7080615
Ref: 2b37080615
Ref: reference/compound_stmts grammar-token-python-grammar-type_params7080777
Ref: 22787080777
Ref: reference/compound_stmts grammar-token-python-grammar-type_param7080862
Ref: 22e97080862
Ref: reference/compound_stmts grammar-token-python-grammar-typevar7080958
Ref: 22ea7080958
Ref: reference/compound_stmts grammar-token-python-grammar-typevartuple7081066
Ref: 22eb7081066
Ref: reference/compound_stmts grammar-token-python-grammar-paramspec7081147
Ref: 22ec7081147
Ref: Type parameter lists-Footnote-17085531
Node: Generic functions7085573
Ref: reference/compound_stmts generic-functions7085671
Ref: 4567085671
Ref: reference/compound_stmts id177085671
Ref: 22ee7085671
Node: Generic classes7087477
Ref: reference/compound_stmts generic-classes7087604
Ref: 4557087604
Ref: reference/compound_stmts id187087604
Ref: 22ef7087604
Node: Generic type aliases7088740
Ref: reference/compound_stmts generic-type-aliases7088841
Ref: 4597088841
Ref: reference/compound_stmts id197088841
Ref: 22f07088841
Node: Top-level components7089645
Ref: reference/toplevel_components doc7089794
Ref: 22f17089794
Ref: reference/toplevel_components top-level7089794
Ref: 22f27089794
Ref: reference/toplevel_components top-level-components7089794
Ref: 22f37089794
Ref: reference/toplevel_components translation-repo7089794
Ref: 22f47089794
Node: Complete Python programs7090187
Ref: reference/toplevel_components complete-python-programs7090287
Ref: 22f57090287
Ref: reference/toplevel_components programs7090287
Ref: 21b17090287
Node: File input7091669
Ref: reference/toplevel_components file-input7091795
Ref: 22f67091795
Ref: reference/toplevel_components id17091795
Ref: 22f77091795
Ref: reference/toplevel_components grammar-token-python-grammar-file_input7091892
Ref: 22f87091892
Node: Interactive input7092181
Ref: reference/toplevel_components interactive7092299
Ref: 22f97092299
Ref: reference/toplevel_components interactive-input7092299
Ref: 22fa7092299
Ref: reference/toplevel_components grammar-token-python-grammar-interactive_input7092414
Ref: 22fb7092414
Node: Expression input7092673
Ref: reference/toplevel_components expression-input7092772
Ref: 22fc7092772
Ref: reference/toplevel_components id27092772
Ref: 22fd7092772
Ref: reference/toplevel_components grammar-token-python-grammar-eval_input7092968
Ref: 22fe7092968
Node: Full Grammar specification7093027
Ref: reference/grammar doc7093148
Ref: 22bd7093148
Ref: reference/grammar full-grammar-specification7093148
Ref: 22ff7093148
Ref: reference/grammar id17093148
Ref: 23007093148
Ref: reference/grammar translation-repo7093148
Ref: 23017093148
Ref: Full Grammar specification-Footnote-17165281
Ref: Full Grammar specification-Footnote-27165353
Ref: Full Grammar specification-Footnote-37165425
Ref: Full Grammar specification-Footnote-47165490
Node: The Python Standard Library7165532
Ref: library/index doc7165692
Ref: 23027165692
Ref: library/index library-index7165692
Ref: 1447165692
Ref: library/index the-python-standard-library7165692
Ref: 23037165692
Ref: library/index translation-repo7165692
Ref: 23047165692
Ref: The Python Standard Library-Footnote-17168504
Node: Introduction<6>7168529
Ref: library/intro doc7168635
Ref: 23057168635
Ref: library/intro introduction7168635
Ref: 23067168635
Ref: library/intro library-intro7168635
Ref: 23077168635
Node: Notes on availability7171319
Ref: library/intro availability7171392
Ref: 1ef77171392
Ref: library/intro notes-on-availability7171392
Ref: 23087171392
Node: WebAssembly platforms7172148
Ref: library/intro wasm-availability7172252
Ref: 19107172252
Ref: library/intro webassembly-platforms7172252
Ref: 23097172252
Ref: library/intro mobile-availability7174736
Ref: 1ffd7174736
Ref: WebAssembly platforms-Footnote-17174773
Ref: WebAssembly platforms-Footnote-27174806
Ref: WebAssembly platforms-Footnote-37174838
Ref: WebAssembly platforms-Footnote-47174864
Ref: WebAssembly platforms-Footnote-57174896
Ref: WebAssembly platforms-Footnote-67174922
Ref: WebAssembly platforms-Footnote-77174952
Ref: WebAssembly platforms-Footnote-87174981
Ref: WebAssembly platforms-Footnote-97175011
Node: Mobile platforms7175071
Ref: library/intro ios-availability7175175
Ref: 230a7175175
Ref: library/intro mobile-platforms7175175
Ref: 230b7175175
Ref: Mobile platforms-Footnote-17177989
Node: Built-in Functions7178055
Ref: library/functions doc7178188
Ref: 230c7178188
Ref: library/functions built-in-funcs7178188
Ref: 12a37178188
Ref: library/functions built-in-functions7178188
Ref: 230d7178188
Ref: library/functions translation-repo7178188
Ref: 230e7178188
Ref: library/functions abs7181626
Ref: 1e457181626
Ref: library/functions aiter7181889
Ref: 7d97181889
Ref: library/functions all7182183
Ref: 14707182183
Ref: library/functions anext7182499
Ref: 7da7182499
Ref: library/functions any7183193
Ref: 146f7183193
Ref: library/functions ascii7183520
Ref: 14347183520
Ref: library/functions bin7183869
Ref: 12f07183869
Ref: library/functions bool7184649
Ref: 46b7184649
Ref: library/functions breakpoint7185276
Ref: 2347185276
Ref: library/functions func-bytearray7186496
Ref: 1c4c7186496
Ref: library/functions func-bytes7187910
Ref: 1c4b7187910
Ref: library/functions callable7188635
Ref: 120b7188635
Ref: library/functions chr7189192
Ref: 17857189192
Ref: library/functions classmethod7189652
Ref: 1667189652
Ref: library/functions compile7191216
Ref: 1927191216
Ref: library/functions complex7195223
Ref: 2f87195223
Ref: library/functions grammar-token-float-complexvalue7196813
Ref: 23217196813
Ref: library/functions delattr7198411
Ref: 230f7198411
Ref: library/functions func-dict7198852
Ref: 23107198852
Ref: library/functions dir7199305
Ref: 6357199305
Ref: library/functions divmod7202064
Ref: 9ac7202064
Ref: library/functions enumerate7202708
Ref: 14d07202708
Ref: library/functions func-eval7203594
Ref: 23257203594
Ref: library/functions eval7203594
Ref: 1807203594
Ref: library/functions exec7206754
Ref: 17f7206754
Ref: library/functions filter7210377
Ref: 86b7210377
Ref: library/functions float7211171
Ref: 2f77211171
Ref: library/functions grammar-token-float-sign7212132
Ref: 23237212132
Ref: library/functions grammar-token-float-infinity7212170
Ref: 23277212170
Ref: library/functions grammar-token-float-nan7212217
Ref: 23287212217
Ref: library/functions grammar-token-float-digit7212251
Ref: 23297212251
Ref: library/functions grammar-token-float-digitpart7212353
Ref: 232a7212353
Ref: library/functions grammar-token-float-number7212428
Ref: 232b7212428
Ref: library/functions grammar-token-float-exponent7212539
Ref: 232c7212539
Ref: library/functions grammar-token-float-floatnumber7212622
Ref: 232d7212622
Ref: library/functions grammar-token-float-absfloatvalue7212694
Ref: 23247212694
Ref: library/functions grammar-token-float-floatvalue7212790
Ref: 23227212790
Ref: library/functions format7213949
Ref: 6227213949
Ref: library/functions func-frozenset7215045
Ref: 23117215045
Ref: library/functions getattr7215512
Ref: bf07215512
Ref: library/functions globals7216351
Ref: 19ae7216351
Ref: library/functions hasattr7216591
Ref: 4d57216591
Ref: library/functions hash7216933
Ref: 5ee7216933
Ref: library/functions help7217465
Ref: 8e07217465
Ref: library/functions hex7218533
Ref: 13177218533
Ref: library/functions id7219616
Ref: 14717219616
Ref: library/functions input7220070
Ref: 13207220070
Ref: library/functions int7220953
Ref: 2577220953
Ref: library/functions isinstance7224153
Ref: 4457224153
Ref: library/functions issubclass7224967
Ref: 7c57224967
Ref: library/functions iter7225539
Ref: 7db7225539
Ref: library/functions len7226983
Ref: 6317226983
Ref: library/functions func-list7227401
Ref: 23127227401
Ref: library/functions locals7227620
Ref: 1417227620
Ref: library/functions map7230223
Ref: 86a7230223
Ref: library/functions max7230758
Ref: f407230758
Ref: library/functions func-memoryview7232022
Ref: 23137232022
Ref: library/functions min7232185
Ref: f3f7232185
Ref: library/functions next7233440
Ref: 7dc7233440
Ref: library/functions object7233754
Ref: a9b7233754
Ref: library/functions oct7234215
Ref: 13167234215
Ref: library/functions open7235014
Ref: 51f7235014
Ref: library/functions filemodes7236502
Ref: 23317236502
Ref: library/functions open-newline-parameter7241643
Ref: 7447241643
Ref: library/functions ord7246531
Ref: 209f7246531
Ref: library/functions pow7247069
Ref: 9dd7247069
Ref: library/functions print7249095
Ref: fae7249095
Ref: library/functions property7250235
Ref: 1947250235
Ref: library/functions property getter7251874
Ref: 176d7251874
Ref: library/functions property setter7251902
Ref: 176e7251902
Ref: library/functions property deleter7251930
Ref: 176f7251930
Ref: library/functions property __name__7253140
Ref: 1937253140
Ref: library/functions func-range7253322
Ref: 23147253322
Ref: library/functions repr7253583
Ref: 8037253583
Ref: library/functions reversed7254599
Ref: 86c7254599
Ref: library/functions round7254932
Ref: 13227254932
Ref: library/functions func-set7256236
Ref: 23157256236
Ref: library/functions setattr7256680
Ref: 23167256680
Ref: library/functions slice7257752
Ref: 46c7257752
Ref: library/functions slice start7258284
Ref: 210b7258284
Ref: library/functions slice stop7258311
Ref: 210c7258311
Ref: library/functions slice step7258337
Ref: 210d7258337
Ref: library/functions sorted7258787
Ref: bed7258787
Ref: library/functions staticmethod7260430
Ref: 4197260430
Ref: library/functions func-str7262186
Ref: 23177262186
Ref: library/functions sum7262593
Ref: 46d7262593
Ref: library/functions super7263447
Ref: 4de7263447
Ref: library/functions func-tuple7267704
Ref: 23187267704
Ref: library/functions type7267929
Ref: d717267929
Ref: library/functions vars7269719
Ref: 1bd27269719
Ref: library/functions zip7270670
Ref: 7d47270670
Ref: library/functions import__7274483
Ref: 8dd7274483
Ref: Built-in Functions-Footnote-17277819
Ref: Built-in Functions-Footnote-27278025
Ref: Built-in Functions-Footnote-37278067
Ref: Built-in Functions-Footnote-47278109
Ref: Built-in Functions-Footnote-57278151
Ref: Built-in Functions-Footnote-67278193
Ref: Built-in Functions-Footnote-77278270
Ref: Built-in Functions-Footnote-87278318
Ref: Built-in Functions-Footnote-97278360
Node: Built-in Constants7278402
Ref: library/constants doc7278534
Ref: 233b7278534
Ref: library/constants built-in-constants7278534
Ref: 233c7278534
Ref: library/constants built-in-consts7278534
Ref: 233d7278534
Ref: library/constants translation-repo7278534
Ref: 233e7278534
Ref: library/constants False7278653
Ref: b4f7278653
Ref: library/constants True7278803
Ref: c2d7278803
Ref: library/constants None7278950
Ref: 6787278950
Ref: library/constants NotImplemented7279248
Ref: 7d67279248
Ref: library/constants Ellipsis7281001
Ref: 233f7281001
Ref: library/constants debug__7281346
Ref: 7de7281346
Node: Constants added by the site module7281815
Ref: library/constants constants-added-by-the-site-module7281904
Ref: 23407281904
Ref: library/constants site-consts7281904
Ref: 23417281904
Ref: library/constants quit7282273
Ref: 23427282273
Ref: library/constants exit7282300
Ref: 23437282300
Ref: library/constants copyright7282866
Ref: 15d47282866
Ref: library/constants credits7282886
Ref: 15d57282886
Ref: library/constants license7283007
Ref: 15d37283007
Node: Built-in Types7283234
Ref: library/stdtypes doc7283367
Ref: 23447283367
Ref: library/stdtypes bltin-types7283367
Ref: 23457283367
Ref: library/stdtypes built-in-types7283367
Ref: 23467283367
Ref: library/stdtypes translation-repo7283367
Ref: 23477283367
Node: Truth Value Testing7284958
Ref: library/stdtypes truth7285070
Ref: 164c7285070
Ref: library/stdtypes truth-value-testing7285070
Ref: 23487285070
Ref: Truth Value Testing-Footnote-17286145
Node: Boolean Operations — and or not7286281
Ref: library/stdtypes boolean7286416
Ref: 23497286416
Ref: library/stdtypes boolean-operations-and-or-not7286416
Ref: 234a7286416
Node: Comparisons<2>7287745
Ref: library/stdtypes comparisons7287896
Ref: 234b7287896
Ref: library/stdtypes stdcomparisons7287896
Ref: 234c7287896
Node: Numeric Types — int float complex7290328
Ref: library/stdtypes numeric-types-int-float-complex7290465
Ref: 234d7290465
Ref: library/stdtypes typesnumeric7290465
Ref: 1d8d7290465
Ref: Numeric Types — int float complex-Footnote-17298634
Ref: Numeric Types — int float complex-Footnote-27298749
Node: Bitwise Operations on Integer Types7298826
Ref: library/stdtypes bitstring-ops7298977
Ref: 234f7298977
Ref: library/stdtypes bitwise-operations-on-integer-types7298977
Ref: 23507298977
Node: Additional Methods on Integer Types7301331
Ref: library/stdtypes additional-methods-on-integer-types7301518
Ref: 23517301518
Ref: library/stdtypes int bit_length7301745
Ref: 23527301745
Ref: library/stdtypes int bit_count7302662
Ref: 7d07302662
Ref: library/stdtypes int to_bytes7303126
Ref: 19d87303126
Ref: library/stdtypes int from_bytes7305298
Ref: 198d7305298
Ref: library/stdtypes int as_integer_ratio7307229
Ref: 9d67307229
Ref: library/stdtypes int is_integer7307536
Ref: 188e7307536
Node: Additional Methods on Float7307700
Ref: library/stdtypes additional-methods-on-float7307876
Ref: 23557307876
Ref: library/stdtypes float as_integer_ratio7308089
Ref: 1eb97308089
Ref: library/stdtypes float is_integer7308375
Ref: 23547308375
Ref: library/stdtypes float hex7309002
Ref: 1eba7309002
Ref: library/stdtypes float fromhex7309252
Ref: 23567309252
Node: Hashing of numeric types7310892
Ref: library/stdtypes hashing-of-numeric-types7311024
Ref: 23577311024
Ref: library/stdtypes numeric-hash7311024
Ref: 23587311024
Ref: library/stdtypes bltin-boolean-values7315183
Ref: 235a7315183
Node: Boolean Type - bool7315184
Ref: library/stdtypes boolean-type-bool7315321
Ref: 235b7315321
Ref: library/stdtypes typebool7315321
Ref: 23197315321
Node: Iterator Types7316513
Ref: library/stdtypes iterator-types7316650
Ref: 235c7316650
Ref: library/stdtypes typeiter7316650
Ref: 232f7316650
Ref: library/stdtypes container __iter__7317044
Ref: 1e627317044
Ref: library/stdtypes iterator __iter__7317791
Ref: 1e657317791
Ref: library/stdtypes iterator __next__7318142
Ref: 13157318142
Node: Generator Types7318924
Ref: library/stdtypes generator-types7318990
Ref: 235d7318990
Ref: library/stdtypes id37318990
Ref: 235e7318990
Node: Sequence Types — list tuple range7319488
Ref: library/stdtypes sequence-types-list-tuple-range7319632
Ref: 235f7319632
Ref: library/stdtypes typesseq7319632
Ref: 1de47319632
Node: Common Sequence Operations7320099
Ref: library/stdtypes common-sequence-operations7320230
Ref: 23607320230
Ref: library/stdtypes typesseq-common7320230
Ref: 23617320230
Ref: library/stdtypes list count7328208
Ref: 14127328208
Ref: library/stdtypes sequence count7328208
Ref: 213e7328208
Ref: library/stdtypes list index7328318
Ref: 14117328318
Ref: library/stdtypes sequence index7328318
Ref: 21407328318
Ref: Common Sequence Operations-Footnote-17328932
Node: Immutable Sequence Types7329011
Ref: library/stdtypes immutable-sequence-types7329173
Ref: 23657329173
Ref: library/stdtypes typesseq-immutable7329173
Ref: 23667329173
Node: Mutable Sequence Types7329706
Ref: library/stdtypes mutable-sequence-types7329850
Ref: 23677329850
Ref: library/stdtypes typesseq-mutable7329850
Ref: 231a7329850
Ref: library/stdtypes bytearray append7333235
Ref: 13f27333235
Ref: library/stdtypes sequence append7333235
Ref: 213c7333235
Ref: library/stdtypes bytearray clear7333400
Ref: 23687333400
Ref: library/stdtypes sequence clear7333400
Ref: 213d7333400
Ref: library/stdtypes bytearray copy7333558
Ref: 23697333558
Ref: library/stdtypes sequence copy7333558
Ref: 236a7333558
Ref: library/stdtypes bytearray extend7333891
Ref: 15dc7333891
Ref: library/stdtypes sequence extend7333891
Ref: 213f7333891
Ref: library/stdtypes bytearray insert7334090
Ref: 236b7334090
Ref: library/stdtypes sequence insert7334090
Ref: 21417334090
Ref: library/stdtypes bytearray pop7334271
Ref: 13f37334271
Ref: library/stdtypes sequence pop7334271
Ref: 21427334271
Ref: library/stdtypes bytearray remove7334453
Ref: 236c7334453
Ref: library/stdtypes sequence remove7334453
Ref: 21437334453
Ref: library/stdtypes bytearray reverse7334651
Ref: 13f47334651
Ref: library/stdtypes sequence reverse7334651
Ref: 21447334651
Node: Lists<2>7334888
Ref: library/stdtypes lists7335014
Ref: 236d7335014
Ref: library/stdtypes typesseq-list7335014
Ref: 1dd87335014
Ref: library/stdtypes list7335197
Ref: 6147335197
Ref: library/stdtypes list sort7336388
Ref: bee7336388
Node: Tuples7338698
Ref: library/stdtypes tuples7338808
Ref: 236e7338808
Ref: library/stdtypes typesseq-tuple7338808
Ref: 22a37338808
Ref: library/stdtypes tuple7339172
Ref: 3737339172
Node: Ranges7340731
Ref: library/stdtypes ranges7340824
Ref: 236f7340824
Ref: library/stdtypes typesseq-range7340824
Ref: 23357340824
Ref: library/stdtypes range7341013
Ref: 94d7341013
Ref: library/stdtypes range start7343003
Ref: 23707343003
Ref: library/stdtypes range stop7343133
Ref: 23717343133
Ref: library/stdtypes range step7343204
Ref: 23727343204
Ref: Ranges-Footnote-17345191
Node: Text Sequence Type — str7345277
Ref: library/stdtypes text-sequence-type-str7345459
Ref: 23737345459
Ref: library/stdtypes textseq7345459
Ref: 1d927345459
Ref: library/stdtypes str7347136
Ref: 44f7347136
Node: String Methods<2>7349395
Ref: library/stdtypes id57349519
Ref: 23757349519
Ref: library/stdtypes string-methods7349519
Ref: 1d937349519
Ref: library/stdtypes str capitalize7350361
Ref: 23787350361
Ref: library/stdtypes str casefold7350727
Ref: e067350727
Ref: library/stdtypes str center7351491
Ref: 1e1b7351491
Ref: library/stdtypes str count7351954
Ref: 174f7351954
Ref: library/stdtypes str encode7352641
Ref: 8de7352641
Ref: library/stdtypes str endswith7353893
Ref: f007353893
Ref: library/stdtypes str expandtabs7354676
Ref: 23797354676
Ref: library/stdtypes str find7355905
Ref: edc7355905
Ref: library/stdtypes str format7356638
Ref: 6247356638
Ref: library/stdtypes str format_map7358406
Ref: e077358406
Ref: library/stdtypes str index7358922
Ref: 17507358922
Ref: library/stdtypes str isalnum7359464
Ref: 237a7359464
Ref: library/stdtypes str isalpha7360010
Ref: 237b7360010
Ref: library/stdtypes str isascii7360842
Ref: b0a7360842
Ref: library/stdtypes str isdecimal7361201
Ref: 237d7361201
Ref: library/stdtypes str isdigit7361820
Ref: 237e7361820
Ref: library/stdtypes str isidentifier7362328
Ref: 1aed7362328
Ref: library/stdtypes str islower7362894
Ref: 23807362894
Ref: library/stdtypes str isnumeric7363078
Ref: 23817363078
Ref: library/stdtypes str isprintable7364024
Ref: e087364024
Ref: library/stdtypes str isspace7365082
Ref: 23827365082
Ref: library/stdtypes str istitle7365786
Ref: 23837365786
Ref: library/stdtypes str isupper7366299
Ref: 23857366299
Ref: library/stdtypes meth-str-join7366674
Ref: 23867366674
Ref: library/stdtypes str join7366674
Ref: 23637366674
Ref: library/stdtypes str ljust7367191
Ref: 1e1a7367191
Ref: library/stdtypes str lower7367725
Ref: 191c7367725
Ref: library/stdtypes str lstrip7368063
Ref: 14ff7368063
Ref: library/stdtypes str maketrans7368883
Ref: e097368883
Ref: library/stdtypes str partition7369675
Ref: edf7369675
Ref: library/stdtypes str removeprefix7370347
Ref: 8d87370347
Ref: library/stdtypes str removesuffix7370775
Ref: 8d97370775
Ref: library/stdtypes str replace7371232
Ref: 19a7371232
Ref: library/stdtypes str rfind7371811
Ref: edd7371811
Ref: library/stdtypes str rindex7372305
Ref: 129e7372305
Ref: library/stdtypes str rjust7372876
Ref: 1e197372876
Ref: library/stdtypes str rpartition7373436
Ref: 129f7373436
Ref: library/stdtypes str rsplit7374109
Ref: 129c7374109
Ref: library/stdtypes str rstrip7374552
Ref: 15007374552
Ref: library/stdtypes str split7375399
Ref: ede7375399
Ref: library/stdtypes str splitlines7377491
Ref: 129d7377491
Ref: library/stdtypes str startswith7380141
Ref: eff7380141
Ref: library/stdtypes str strip7380766
Ref: 14fe7380766
Ref: library/stdtypes str swapcase7381841
Ref: 23887381841
Ref: library/stdtypes str title7382058
Ref: 23847382058
Ref: library/stdtypes str translate7383282
Ref: 23877383282
Ref: library/stdtypes str upper7384191
Ref: 238b7384191
Ref: library/stdtypes str zfill7384682
Ref: 15017384682
Ref: String Methods<2>-Footnote-17385242
Ref: String Methods<2>-Footnote-27385306
Ref: String Methods<2>-Footnote-37385370
Ref: String Methods<2>-Footnote-47385542
Ref: String Methods<2>-Footnote-57385714
Ref: String Methods<2>-Footnote-67385886
Ref: String Methods<2>-Footnote-77385950
Ref: String Methods<2>-Footnote-87386122
Node: Formatted String Literals f-strings7386186
Ref: library/stdtypes formatted-string-literals-f-strings7386349
Ref: 238c7386349
Node: printf-style String Formatting7390063
Ref: library/stdtypes old-string-formatting7390200
Ref: 6cf7390200
Ref: library/stdtypes printf-style-string-formatting7390200
Ref: 238d7390200
Ref: printf-style String Formatting-Footnote-17399725
Ref: printf-style String Formatting-Footnote-27399852
Node: Binary Sequence Types — bytes bytearray memoryview7399894
Ref: library/stdtypes binary-sequence-types-bytes-bytearray-memoryview7400068
Ref: 238f7400068
Ref: library/stdtypes binaryseq7400068
Ref: 231c7400068
Node: Bytes Objects7400759
Ref: library/stdtypes bytes-objects7400887
Ref: 23907400887
Ref: library/stdtypes typebytes7400887
Ref: 231e7400887
Ref: library/stdtypes bytes7401227
Ref: 1c27401227
Ref: library/stdtypes bytes fromhex7403515
Ref: b087403515
Ref: library/stdtypes bytes hex7404103
Ref: d937404103
Node: Bytearray Objects7405781
Ref: library/stdtypes bytearray-objects7405948
Ref: 23917405948
Ref: library/stdtypes typebytearray7405948
Ref: 231d7405948
Ref: library/stdtypes bytearray7406088
Ref: 2ea7406088
Ref: library/stdtypes bytearray fromhex7407164
Ref: b097407164
Ref: library/stdtypes bytearray hex7407791
Ref: d947407791
Node: Bytes and Bytearray Operations7408879
Ref: library/stdtypes bytes-and-bytearray-operations7409062
Ref: 23927409062
Ref: library/stdtypes bytes-methods7409062
Ref: 231b7409062
Ref: library/stdtypes bytes count7410280
Ref: 23937410280
Ref: library/stdtypes bytearray count7410326
Ref: 15e07410326
Ref: library/stdtypes bytes removeprefix7410923
Ref: 23947410923
Ref: library/stdtypes bytearray removeprefix7410966
Ref: 23957410966
Ref: library/stdtypes bytes removesuffix7411571
Ref: 23967411571
Ref: library/stdtypes bytearray removesuffix7411614
Ref: 23977411614
Ref: library/stdtypes bytes decode7412250
Ref: 8df7412250
Ref: library/stdtypes bytearray decode7412311
Ref: 23987412311
Ref: library/stdtypes bytes endswith7413551
Ref: 23997413551
Ref: library/stdtypes bytearray endswith7413603
Ref: 13ef7413603
Ref: library/stdtypes bytes find7414030
Ref: 19797414030
Ref: library/stdtypes bytearray find7414075
Ref: 13f07414075
Ref: library/stdtypes bytes index7414874
Ref: 239a7414874
Ref: library/stdtypes bytearray index7414920
Ref: 15e17414920
Ref: library/stdtypes bytes join7415294
Ref: 23647415294
Ref: library/stdtypes bytearray join7415331
Ref: 239b7415331
Ref: library/stdtypes bytes maketrans7415770
Ref: 12bb7415770
Ref: library/stdtypes bytearray maketrans7415819
Ref: 12bc7415819
Ref: library/stdtypes bytes partition7416190
Ref: 239d7416190
Ref: library/stdtypes bytearray partition7416227
Ref: 239e7416227
Ref: library/stdtypes bytes replace7416717
Ref: 239f7416717
Ref: library/stdtypes bytearray replace7416767
Ref: 23a07416767
Ref: library/stdtypes bytes rfind7417291
Ref: 197a7417291
Ref: library/stdtypes bytearray rfind7417337
Ref: 13f17417337
Ref: library/stdtypes bytes rindex7417867
Ref: 23a17417867
Ref: library/stdtypes bytearray rindex7417914
Ref: 15e27417914
Ref: library/stdtypes bytes rpartition7418297
Ref: 23a27418297
Ref: library/stdtypes bytearray rpartition7418335
Ref: 23a37418335
Ref: library/stdtypes bytes startswith7418825
Ref: 23a47418825
Ref: library/stdtypes bytearray startswith7418879
Ref: 13ee7418879
Ref: library/stdtypes bytes translate7419315
Ref: 239c7419315
Ref: library/stdtypes bytearray translate7419366
Ref: 13447419366
Ref: library/stdtypes bytes center7420388
Ref: 23a57420388
Ref: library/stdtypes bytearray center7420439
Ref: 23a67420439
Ref: library/stdtypes bytes ljust7420946
Ref: 23a77420946
Ref: library/stdtypes bytearray ljust7420996
Ref: 23a87420996
Ref: library/stdtypes bytes lstrip7421508
Ref: 23a97421508
Ref: library/stdtypes bytearray lstrip7421549
Ref: 23aa7421549
Ref: library/stdtypes bytes rjust7422669
Ref: 23ab7422669
Ref: library/stdtypes bytearray rjust7422719
Ref: 23ac7422719
Ref: library/stdtypes bytes rsplit7423232
Ref: 23ad7423232
Ref: library/stdtypes bytearray rsplit7423281
Ref: 15e57423281
Ref: library/stdtypes bytes rstrip7423788
Ref: 23ae7423788
Ref: library/stdtypes bytearray rstrip7423829
Ref: 23af7423829
Ref: library/stdtypes bytes split7424931
Ref: 23b07424931
Ref: library/stdtypes bytearray split7424979
Ref: 15e47424979
Ref: library/stdtypes bytes strip7426912
Ref: 23b17426912
Ref: library/stdtypes bytearray strip7426952
Ref: 23b27426952
Ref: library/stdtypes bytes capitalize7428059
Ref: 23b37428059
Ref: library/stdtypes bytearray capitalize7428091
Ref: 23b47428091
Ref: library/stdtypes bytes expandtabs7428500
Ref: 23b57428500
Ref: library/stdtypes bytearray expandtabs7428541
Ref: 23b67428541
Ref: library/stdtypes bytes isalnum7429883
Ref: 23b77429883
Ref: library/stdtypes bytearray isalnum7429912
Ref: 23b87429912
Ref: library/stdtypes bytes isalpha7430474
Ref: 23b97430474
Ref: library/stdtypes bytearray isalpha7430503
Ref: 23ba7430503
Ref: library/stdtypes bytes isascii7430940
Ref: 23bb7430940
Ref: library/stdtypes bytearray isascii7430969
Ref: 23bc7430969
Ref: library/stdtypes bytes isdigit7431186
Ref: 23bd7431186
Ref: library/stdtypes bytearray isdigit7431215
Ref: 23be7431215
Ref: library/stdtypes bytes islower7431587
Ref: 23bf7431587
Ref: library/stdtypes bytearray islower7431616
Ref: 23c07431616
Ref: library/stdtypes bytes isspace7432154
Ref: 23c17432154
Ref: library/stdtypes bytearray isspace7432183
Ref: 23c27432183
Ref: library/stdtypes bytes istitle7432515
Ref: 23c37432515
Ref: library/stdtypes bytearray istitle7432544
Ref: 23c47432544
Ref: library/stdtypes bytes isupper7432917
Ref: 23c67432917
Ref: library/stdtypes bytearray isupper7432946
Ref: 23c77432946
Ref: library/stdtypes bytes lower7433500
Ref: 23c87433500
Ref: library/stdtypes bytearray lower7433527
Ref: 23c97433527
Ref: library/stdtypes bytes splitlines7434166
Ref: 23ca7434166
Ref: library/stdtypes bytearray splitlines7434212
Ref: 23cb7434212
Ref: library/stdtypes bytes swapcase7435161
Ref: 23cc7435161
Ref: library/stdtypes bytearray swapcase7435191
Ref: 23cd7435191
Ref: library/stdtypes bytes title7436121
Ref: 23c57436121
Ref: library/stdtypes bytearray title7436148
Ref: 23ce7436148
Ref: library/stdtypes bytes upper7437773
Ref: 23cf7437773
Ref: library/stdtypes bytearray upper7437800
Ref: 23d07437800
Ref: library/stdtypes bytes zfill7438439
Ref: 23d17438439
Ref: library/stdtypes bytearray zfill7438474
Ref: 23d27438474
Node: printf-style Bytes Formatting7439187
Ref: library/stdtypes bytes-formatting7439365
Ref: daf7439365
Ref: library/stdtypes printf-style-bytes-formatting7439365
Ref: 23d37439365
Ref: printf-style Bytes Formatting-Footnote-17448860
Ref: printf-style Bytes Formatting-Footnote-27448987
Ref: printf-style Bytes Formatting-Footnote-37449029
Node: Memory Views7449071
Ref: library/stdtypes memory-views7449210
Ref: 23d47449210
Ref: library/stdtypes typememoryview7449210
Ref: 23307449210
Ref: library/stdtypes memoryview7449407
Ref: 2eb7449407
Ref: library/stdtypes memoryview __eq__7453204
Ref: 23d87453204
Ref: library/stdtypes memoryview tobytes7455206
Ref: 23d97455206
Ref: library/stdtypes memoryview hex7456303
Ref: d957456303
Ref: library/stdtypes memoryview tolist7456861
Ref: 23d57456861
Ref: library/stdtypes memoryview toreadonly7457416
Ref: 23da7457416
Ref: library/stdtypes memoryview release7458030
Ref: 12037458030
Ref: library/stdtypes memoryview cast7459392
Ref: 23db7459392
Ref: library/stdtypes memoryview obj7462489
Ref: 23dd7462489
Ref: library/stdtypes memoryview nbytes7462729
Ref: 23de7462729
Ref: library/stdtypes memoryview readonly7463857
Ref: 23df7463857
Ref: library/stdtypes memoryview format7463949
Ref: 23d77463949
Ref: library/stdtypes memoryview itemsize7464487
Ref: 23d67464487
Ref: library/stdtypes memoryview ndim7464863
Ref: 23e07464863
Ref: library/stdtypes memoryview shape7465004
Ref: 23e17465004
Ref: library/stdtypes memoryview strides7465259
Ref: 23e27465259
Ref: library/stdtypes memoryview suboffsets7465549
Ref: 23e37465549
Ref: library/stdtypes memoryview c_contiguous7465674
Ref: 23e47465674
Ref: library/stdtypes memoryview f_contiguous7465828
Ref: 23e57465828
Ref: library/stdtypes memoryview contiguous7465988
Ref: 23e67465988
Ref: Memory Views-Footnote-17466174
Node: Set Types — set frozenset7466216
Ref: library/stdtypes set-types-set-frozenset7466386
Ref: 23e77466386
Ref: library/stdtypes types-set7466386
Ref: 1de77466386
Ref: library/stdtypes set7467937
Ref: 5dc7467937
Ref: library/stdtypes frozenset7467969
Ref: 5dd7467969
Ref: library/stdtypes frozenset isdisjoint7468922
Ref: 23e97468922
Ref: library/stdtypes set isdisjoint7468966
Ref: 23ea7468966
Ref: library/stdtypes frozenset issubset7469160
Ref: 23eb7469160
Ref: library/stdtypes set issubset7469202
Ref: 23ec7469202
Ref: library/stdtypes frozenset issuperset7469462
Ref: 23ed7469462
Ref: library/stdtypes set issuperset7469506
Ref: 192b7469506
Ref: library/stdtypes frozenset union7469770
Ref: 14d27469770
Ref: library/stdtypes set union7469808
Ref: 23ee7469808
Ref: library/stdtypes frozenset intersection7469940
Ref: 14d37469940
Ref: library/stdtypes set intersection7469985
Ref: 192a7469985
Ref: library/stdtypes frozenset difference7470129
Ref: 23ef7470129
Ref: library/stdtypes set difference7470172
Ref: 23f07470172
Ref: library/stdtypes frozenset symmetric_difference7470324
Ref: 23f17470324
Ref: library/stdtypes set symmetric_difference7470378
Ref: 23f27470378
Ref: library/stdtypes frozenset copy7470539
Ref: 23f37470539
Ref: library/stdtypes set copy7470569
Ref: 23f47470569
Ref: library/stdtypes set update7472625
Ref: 23f57472625
Ref: library/stdtypes set intersection_update7472748
Ref: 14d47472748
Ref: library/stdtypes set difference_update7472901
Ref: 23f67472901
Ref: library/stdtypes set symmetric_difference_update7473037
Ref: 14d57473037
Ref: library/stdtypes set add7473208
Ref: 20a27473208
Ref: library/stdtypes set remove7473276
Ref: 23e87473276
Ref: library/stdtypes set discard7473425
Ref: 23f77473425
Ref: library/stdtypes set pop7473519
Ref: 23f87473519
Ref: library/stdtypes set clear7473657
Ref: 23f97473657
Node: Mapping Types — dict7474173
Ref: library/stdtypes mapping-types-dict7474312
Ref: 23fa7474312
Ref: library/stdtypes typesmapping7474312
Ref: adc7474312
Ref: library/stdtypes dict7475097
Ref: 2567475097
Ref: library/stdtypes dict clear7480579
Ref: 15bb7480579
Ref: library/stdtypes dict copy7480655
Ref: bef7480655
Ref: library/stdtypes dict fromkeys7480733
Ref: 16567480733
Ref: library/stdtypes dict get7481263
Ref: 1dea7481263
Ref: library/stdtypes dict items7481524
Ref: 7d37481524
Ref: library/stdtypes dict keys7481698
Ref: 7d17481698
Ref: library/stdtypes dict pop7481843
Ref: 3447481843
Ref: library/stdtypes dict popitem7482128
Ref: 15767482128
Ref: library/stdtypes dict setdefault7482882
Ref: 10b77482882
Ref: library/stdtypes dict update7483118
Ref: 14b47483118
Ref: library/stdtypes dict values7483850
Ref: 7d27483850
Node: Dictionary view objects7485543
Ref: library/stdtypes dict-views7485625
Ref: 23fb7485625
Ref: library/stdtypes dictionary-view-objects7485625
Ref: 23fc7485625
Node: Context Manager Types7489220
Ref: library/stdtypes context-manager-types7489377
Ref: 23fe7489377
Ref: library/stdtypes typecontextmanager7489377
Ref: 21717489377
Ref: library/stdtypes contextmanager __enter__7489742
Ref: 23ff7489742
Ref: library/stdtypes contextmanager __exit__7490742
Ref: 24007490742
Node: Type Annotation Types — Generic Alias Union7493214
Ref: library/stdtypes type-annotation-types-generic-alias-union7493369
Ref: 24017493369
Node: Generic Alias Type7493634
Ref: library/stdtypes generic-alias-type7493753
Ref: 24027493753
Ref: library/stdtypes types-genericalias7493753
Ref: 6b57493753
Node: Standard Generic Classes7498553
Ref: library/stdtypes standard-generic-classes7498683
Ref: 24047498683
Node: Special Attributes of GenericAlias objects7501074
Ref: library/stdtypes special-attributes-of-genericalias-objects7501204
Ref: 24127501204
Ref: library/stdtypes genericalias __origin__7501385
Ref: 24137501385
Ref: library/stdtypes genericalias __args__7501554
Ref: 24037501554
Ref: library/stdtypes genericalias __parameters__7501845
Ref: 24147501845
Ref: library/stdtypes genericalias __unpacked__7502396
Ref: 24157502396
Ref: Special Attributes of GenericAlias objects-Footnote-17503214
Ref: Special Attributes of GenericAlias objects-Footnote-27503256
Node: Union Type7503298
Ref: library/stdtypes types-union7503417
Ref: 7c67503417
Ref: library/stdtypes union-type7503417
Ref: 24167503417
Ref: Union Type-Footnote-17506839
Node: Other Built-in Types7506881
Ref: library/stdtypes other-built-in-types7507033
Ref: 24177507033
Ref: library/stdtypes typesother7507033
Ref: 24187507033
Node: Modules<4>7507419
Ref: library/stdtypes modules7507522
Ref: 24197507522
Ref: library/stdtypes typesmodules7507522
Ref: 241a7507522
Node: Classes and Class Instances7508663
Ref: library/stdtypes classes-and-class-instances7508784
Ref: 241b7508784
Ref: library/stdtypes typesobjects7508784
Ref: 241c7508784
Node: Functions7508949
Ref: library/stdtypes functions7509067
Ref: 241d7509067
Ref: library/stdtypes typesfunctions7509067
Ref: 241e7509067
Node: Methods7509531
Ref: library/stdtypes methods7509634
Ref: 241f7509634
Ref: library/stdtypes typesmethods7509634
Ref: 24207509634
Node: Code Objects7511468
Ref: library/stdtypes bltin-code-objects7511574
Ref: 24217511574
Ref: library/stdtypes code-objects7511574
Ref: 24227511574
Node: Type Objects7512428
Ref: library/stdtypes bltin-type-objects7512542
Ref: 233a7512542
Ref: library/stdtypes type-objects7512542
Ref: 24237512542
Node: The Null Object7512893
Ref: library/stdtypes bltin-null-object7513014
Ref: 24247513014
Ref: library/stdtypes the-null-object7513014
Ref: 24257513014
Node: The Ellipsis Object7513329
Ref: library/stdtypes bltin-ellipsis-object7513463
Ref: 1db27513463
Ref: library/stdtypes the-ellipsis-object7513463
Ref: 24267513463
Ref: The Ellipsis Object-Footnote-17514658
Node: The NotImplemented Object7514743
Ref: library/stdtypes bltin-notimplemented-object7514878
Ref: 24297514878
Ref: library/stdtypes the-notimplemented-object7514878
Ref: 242a7514878
Node: Internal Objects7515287
Ref: library/stdtypes internal-objects7515394
Ref: 242b7515394
Ref: library/stdtypes typesinternal7515394
Ref: 242c7515394
Node: Special Attributes7515612
Ref: library/stdtypes special-attributes7515762
Ref: 242d7515762
Ref: library/stdtypes specialattrs7515762
Ref: 242e7515762
Ref: library/stdtypes definition __name__7516001
Ref: 10a47516001
Ref: library/stdtypes definition __qualname__7516124
Ref: 10a37516124
Ref: library/stdtypes definition __module__7516302
Ref: 242f7516302
Ref: library/stdtypes definition __doc__7516411
Ref: 9317516411
Ref: library/stdtypes definition __type_params__7516534
Ref: 22ed7516534
Node: Integer string conversion length limitation7516792
Ref: library/stdtypes int-max-str-digits7516913
Ref: 5f87516913
Ref: library/stdtypes integer-string-conversion-length-limitation7516913
Ref: 24307516913
Ref: Integer string conversion length limitation-Footnote-17519644
Node: Affected APIs7519700
Ref: library/stdtypes affected-apis7519823
Ref: 24317519823
Node: Configuring the limit7520753
Ref: library/stdtypes configuring-the-limit7520910
Ref: 24327520910
Node: Recommended configuration7523379
Ref: library/stdtypes recommended-configuration7523514
Ref: 24357523514
Node: Built-in Exceptions7524384
Ref: library/exceptions doc7524523
Ref: 24367524523
Ref: library/exceptions bltin-exceptions7524523
Ref: 19cc7524523
Ref: library/exceptions built-in-exceptions7524523
Ref: 24377524523
Ref: library/exceptions translation-repo7524523
Ref: 24387524523
Node: Exception context7526255
Ref: library/exceptions exception-context7526372
Ref: 24397526372
Ref: library/exceptions BaseException __context__7526533
Ref: 130f7526533
Ref: library/exceptions BaseException __cause__7526574
Ref: 13107526574
Ref: library/exceptions BaseException __suppress_context__7526613
Ref: 226d7526613
Node: Inheriting from built-in exceptions7528306
Ref: library/exceptions inheriting-from-built-in-exceptions7528444
Ref: 243a7528444
Ref: Inheriting from built-in exceptions-Footnote-17529326
Node: Base classes7529399
Ref: library/exceptions base-classes7529539
Ref: 243b7529539
Ref: library/exceptions BaseException7529658
Ref: 5be7529658
Ref: library/exceptions BaseException args7530043
Ref: 56f7530043
Ref: library/exceptions BaseException with_traceback7530411
Ref: 226c7530411
Ref: library/exceptions BaseException __traceback__7531311
Ref: 130e7531311
Ref: library/exceptions BaseException add_note7531513
Ref: 5bd7531513
Ref: library/exceptions BaseException __notes__7531798
Ref: 243c7531798
Ref: library/exceptions Exception7532038
Ref: 9e57532038
Ref: library/exceptions ArithmeticError7532222
Ref: 243d7532222
Ref: library/exceptions BufferError7532450
Ref: 15e37532450
Ref: library/exceptions LookupError7532561
Ref: 238a7532561
Ref: Base classes-Footnote-17532863
Node: Concrete exceptions7532905
Ref: library/exceptions concrete-exceptions7533018
Ref: 243f7533018
Ref: library/exceptions AssertionError7533141
Ref: 6ac7533141
Ref: library/exceptions AttributeError7533229
Ref: 34e7533229
Ref: library/exceptions AttributeError name7533597
Ref: 24407533597
Ref: library/exceptions AttributeError obj7533695
Ref: 24417533695
Ref: library/exceptions EOFError7533882
Ref: 13217533882
Ref: library/exceptions FloatingPointError7534171
Ref: 243e7534171
Ref: library/exceptions GeneratorExit7534232
Ref: 14147534232
Ref: library/exceptions ImportError7534555
Ref: 41c7534555
Ref: library/exceptions ImportError name7534877
Ref: 24427534877
Ref: library/exceptions ImportError path7534972
Ref: 24437534972
Ref: library/exceptions ModuleNotFoundError7535158
Ref: b617535158
Ref: library/exceptions IndexError7535422
Ref: 15857535422
Ref: library/exceptions KeyError7535649
Ref: 3457535649
Ref: library/exceptions KeyboardInterrupt7535766
Ref: 9dc7535766
Ref: library/exceptions MemoryError7536626
Ref: 15ab7536626
Ref: library/exceptions NameError7537207
Ref: 4427537207
Ref: library/exceptions NameError name7537497
Ref: 24457537497
Ref: library/exceptions NotImplementedError7537664
Ref: 2287537664
Ref: library/exceptions OSError7538540
Ref: 41a7538540
Ref: library/exceptions OSError errno7539566
Ref: 15fa7539566
Ref: library/exceptions OSError winerror7539658
Ref: 24477539658
Ref: library/exceptions OSError strerror7540237
Ref: 24487540237
Ref: library/exceptions OSError filename7540473
Ref: 24497540473
Ref: library/exceptions OSError filename27540502
Ref: 244a7540502
Ref: library/exceptions OverflowError7541516
Ref: 8887541516
Ref: library/exceptions PythonFinalizationError7542009
Ref: 14d7542009
Ref: library/exceptions RecursionError7542588
Ref: d967542588
Ref: library/exceptions ReferenceError7542912
Ref: 155d7542912
Ref: library/exceptions RuntimeError7543238
Ref: 1957543238
Ref: library/exceptions StopIteration7543440
Ref: c1b7543440
Ref: library/exceptions StopIteration value7543662
Ref: 217a7543662
Ref: library/exceptions StopAsyncIteration7544791
Ref: 1bbe7544791
Ref: library/exceptions SyntaxError7544985
Ref: 18d7544985
Ref: library/exceptions SyntaxError filename7545507
Ref: 244b7545507
Ref: library/exceptions SyntaxError lineno7545599
Ref: 244c7545599
Ref: library/exceptions SyntaxError offset7545773
Ref: 244d7545773
Ref: library/exceptions SyntaxError text7545959
Ref: 244e7545959
Ref: library/exceptions SyntaxError end_lineno7546040
Ref: 244f7546040
Ref: library/exceptions SyntaxError end_offset7546232
Ref: 24507546232
Ref: library/exceptions IndentationError7546866
Ref: 7ac7546866
Ref: library/exceptions TabError7547019
Ref: 5467547019
Ref: library/exceptions SystemError7547180
Ref: 5787547180
Ref: library/exceptions SystemExit7548090
Ref: d697548090
Ref: library/exceptions SystemExit code7549378
Ref: 24527549378
Ref: library/exceptions TypeError7549520
Ref: 2c37549520
Ref: library/exceptions UnboundLocalError7550344
Ref: 15867550344
Ref: library/exceptions UnicodeError7550562
Ref: 12eb7550562
Ref: library/exceptions UnicodeError encoding7550917
Ref: 24537550917
Ref: library/exceptions UnicodeError reason7551006
Ref: 24547551006
Ref: library/exceptions UnicodeError object7551091
Ref: 24557551091
Ref: library/exceptions UnicodeError start7551187
Ref: 16c07551187
Ref: library/exceptions UnicodeError end7551279
Ref: 16c17551279
Ref: library/exceptions UnicodeEncodeError7551375
Ref: 67a7551375
Ref: library/exceptions UnicodeDecodeError7551528
Ref: a207551528
Ref: library/exceptions UnicodeTranslateError7551681
Ref: 24567551681
Ref: library/exceptions ValueError7551840
Ref: 2027551840
Ref: library/exceptions ZeroDivisionError7552093
Ref: 94f7552093
Ref: library/exceptions EnvironmentError7552450
Ref: 10917552450
Ref: library/exceptions IOError7552483
Ref: 10907552483
Ref: library/exceptions WindowsError7552507
Ref: 10927552507
Ref: Concrete exceptions-Footnote-17552633
Ref: Concrete exceptions-Footnote-27552675
Node: OS exceptions7552717
Ref: library/exceptions os-exceptions7552786
Ref: 24467552786
Ref: library/exceptions BlockingIOError7552947
Ref: 10957552947
Ref: library/exceptions BlockingIOError characters_written7553327
Ref: 245b7553327
Ref: library/exceptions ChildProcessError7553579
Ref: 10967553579
Ref: library/exceptions ConnectionError7553724
Ref: e3c7553724
Ref: library/exceptions BrokenPipeError7553976
Ref: 109a7553976
Ref: library/exceptions ConnectionAbortedError7554288
Ref: 109b7554288
Ref: library/exceptions ConnectionRefusedError7554496
Ref: 109c7554496
Ref: library/exceptions ConnectionResetError7554704
Ref: 109d7554704
Ref: library/exceptions FileExistsError7554898
Ref: 105b7554898
Ref: library/exceptions FileNotFoundError7555060
Ref: 42e7555060
Ref: library/exceptions InterruptedError7555218
Ref: db67555218
Ref: library/exceptions IsADirectoryError7555619
Ref: 10977555619
Ref: library/exceptions NotADirectoryError7555810
Ref: 10987555810
Ref: library/exceptions PermissionError7556182
Ref: d6b7556182
Ref: library/exceptions ProcessLookupError7556555
Ref: 10997556555
Ref: library/exceptions TimeoutError7556693
Ref: 83b7556693
Ref: OS exceptions-Footnote-17557038
Ref: OS exceptions-Footnote-27557080
Node: Warnings7557122
Ref: library/exceptions warning-categories-as-exceptions7557239
Ref: 24697557239
Ref: library/exceptions warnings7557239
Ref: 246a7557239
Ref: library/exceptions Warning7557400
Ref: 246c7557400
Ref: library/exceptions UserWarning7557465
Ref: 246d7557465
Ref: library/exceptions DeprecationWarning7557547
Ref: 1a57557547
Ref: library/exceptions PendingDeprecationWarning7557939
Ref: 8d17557939
Ref: library/exceptions SyntaxWarning7558511
Ref: 4697558511
Ref: library/exceptions RuntimeWarning7558746
Ref: 1bd7558746
Ref: library/exceptions FutureWarning7558839
Ref: 4187558839
Ref: library/exceptions ImportWarning7559026
Ref: 4fd7559026
Ref: library/exceptions UnicodeWarning7559250
Ref: 14727559250
Ref: library/exceptions EncodingWarning7559331
Ref: 1ee57559331
Ref: library/exceptions BytesWarning7559503
Ref: c437559503
Ref: library/exceptions ResourceWarning7559622
Ref: 2447559622
Ref: Warnings-Footnote-17559896
Ref: Warnings-Footnote-27559938
Ref: Warnings-Footnote-37559980
Node: Exception groups7560022
Ref: library/exceptions exception-groups7560139
Ref: 246e7560139
Ref: library/exceptions lib-exception-groups7560139
Ref: 246f7560139
Ref: library/exceptions ExceptionGroup7560522
Ref: 1b67560522
Ref: library/exceptions BaseExceptionGroup7560565
Ref: 25f7560565
Ref: library/exceptions BaseExceptionGroup message7561777
Ref: 24707561777
Ref: library/exceptions BaseExceptionGroup exceptions7561902
Ref: 24717561902
Ref: library/exceptions BaseExceptionGroup subgroup7562066
Ref: 17d17562066
Ref: library/exceptions BaseExceptionGroup split7563412
Ref: 168f7563412
Ref: library/exceptions BaseExceptionGroup derive7563647
Ref: 17d07563647
Node: Exception hierarchy7566634
Ref: library/exceptions exception-hierarchy7566734
Ref: 24727566734
Ref: library/text stringservices7569610
Ref: 23747569610
Node: Text Processing Services7569611
Ref: library/text doc7569756
Ref: 24737569756
Ref: library/text text-processing-services7569756
Ref: 24747569756
Ref: library/text textservices7569756
Ref: 23777569756
Ref: library/text translation-repo7569756
Ref: 24757569756
Node: string — Common string operations7570544
Ref: library/string doc7570685
Ref: 24777570685
Ref: library/string module-string7570685
Ref: d37570685
Ref: library/string string-common-string-operations7570685
Ref: 24787570685
Ref: string — Common string operations-Footnote-17571129
Node: String constants7571195
Ref: library/string string-constants7571316
Ref: 24797571316
Ref: library/string string ascii_letters7571410
Ref: 130b7571410
Ref: library/string string ascii_lowercase7571609
Ref: 247a7571609
Ref: library/string string ascii_uppercase7571769
Ref: 247b7571769
Ref: library/string string digits7571929
Ref: 247c7571929
Ref: library/string string hexdigits7571991
Ref: 247d7571991
Ref: library/string string octdigits7572068
Ref: 247e7572068
Ref: library/string string punctuation7572131
Ref: 247f7572131
Ref: library/string string printable7572306
Ref: 168c7572306
Ref: library/string string whitespace7572767
Ref: 24807572767
Ref: String constants-Footnote-17573009
Node: Custom string formatting7573055
Ref: library/string custom-string-formatting7573205
Ref: 24817573205
Ref: library/string string-formatting7573205
Ref: 23767573205
Ref: library/string string Formatter7573641
Ref: ef17573641
Ref: library/string string Formatter format7573736
Ref: c207573736
Ref: library/string string Formatter vformat7574097
Ref: 24827574097
Ref: library/string string Formatter parse7574795
Ref: 24837574795
Ref: library/string string Formatter get_field7575551
Ref: 24847575551
Ref: library/string string Formatter get_value7576100
Ref: 24857576100
Ref: library/string string Formatter check_unused_args7577313
Ref: 24867577313
Ref: library/string string Formatter format_field7577910
Ref: 24877577910
Ref: library/string string Formatter convert_field7578129
Ref: 24887578129
Ref: Custom string formatting-Footnote-17578504
Ref: Custom string formatting-Footnote-27578546
Node: Format string syntax7578588
Ref: library/string format-string-syntax7578738
Ref: 24897578738
Ref: library/string formatstrings7578738
Ref: 13e87578738
Ref: library/string grammar-token-format-string-replacement_field7579535
Ref: 248a7579535
Ref: library/string grammar-token-format-string-field_name7579657
Ref: 248b7579657
Ref: library/string grammar-token-format-string-arg_name7579778
Ref: 248e7579778
Ref: library/string grammar-token-format-string-attribute_name7579853
Ref: 248f7579853
Ref: library/string grammar-token-format-string-element_index7579904
Ref: 24907579904
Ref: library/string grammar-token-format-string-index_string7579979
Ref: 24917579979
Ref: library/string grammar-token-format-string-conversion7580042
Ref: 248c7580042
Ref: library/string grammar-token-format-string-format_spec7580085
Ref: 248d7580085
Node: Format specification mini-language7584191
Ref: library/string format-specification-mini-language7584306
Ref: 24947584306
Ref: library/string formatspec7584306
Ref: 1e87584306
Ref: library/string grammar-token-format-spec-format_spec7585188
Ref: 24927585188
Ref: library/string grammar-token-format-spec-options7585322
Ref: 24957585322
Ref: library/string grammar-token-format-spec-fill7585417
Ref: 249a7585417
Ref: library/string grammar-token-format-spec-align7585454
Ref: 249b7585454
Ref: library/string grammar-token-format-spec-sign7585497
Ref: 249c7585497
Ref: library/string grammar-token-format-spec-width7585534
Ref: 24967585534
Ref: library/string grammar-token-format-spec-grouping7585575
Ref: 24977585575
Ref: library/string grammar-token-format-spec-precision7585606
Ref: 24987585606
Ref: library/string grammar-token-format-spec-type7585647
Ref: 24997585647
Ref: Format specification mini-language-Footnote-17600493
Ref: Format specification mini-language-Footnote-27600535
Ref: Format specification mini-language-Footnote-37600577
Node: Format examples7600619
Ref: library/string format-examples7600734
Ref: 249e7600734
Ref: library/string formatexamples7600734
Ref: 24937600734
Node: Template strings7605473
Ref: library/string id17605615
Ref: 249f7605615
Ref: library/string template-strings7605615
Ref: 238e7605615
Ref: library/string string Template7607065
Ref: 68a7607065
Ref: library/string string Template substitute7607185
Ref: 1e8d7607185
Ref: library/string string Template safe_substitute7607670
Ref: 1e8e7607670
Ref: library/string string Template is_valid7608612
Ref: 6897608612
Ref: library/string string Template get_identifiers7608842
Ref: 6887608842
Ref: library/string string Template template7609128
Ref: 24a07609128
Ref: Template strings-Footnote-17613049
Ref: Template strings-Footnote-27613091
Node: Helper functions7613143
Ref: library/string helper-functions7613256
Ref: 24a17613256
Ref: library/string string capwords7613307
Ref: 23897613307
Node: re — Regular expression operations7613793
Ref: library/re doc7613983
Ref: 24a27613983
Ref: library/re module-re7613983
Ref: b97613983
Ref: library/re re-regular-expression-operations7613983
Ref: 24a37613983
Ref: library/re translation-repo7613983
Ref: 24a47613983
Ref: re — Regular expression operations-Footnote-17616546
Ref: re — Regular expression operations-Footnote-27616606
Node: Regular Expression Syntax7616646
Ref: library/re re-syntax7616768
Ref: 7277616768
Ref: library/re regular-expression-syntax7616768
Ref: 24a57616768
Ref: library/re re-conditional-expression7637626
Ref: 18cb7637626
Ref: library/re re-special-sequences7638315
Ref: 24b27638315
Ref: Regular Expression Syntax-Footnote-17644709
Ref: Regular Expression Syntax-Footnote-27644751
Node: Module Contents7644823
Ref: library/re contents-of-module-re7644980
Ref: 24b17644980
Ref: library/re module-contents7644980
Ref: 24b37644980
Node: Flags7645344
Ref: library/re flags7645422
Ref: 24b47645422
Ref: library/re re RegexFlag7645582
Ref: 6307645582
Ref: library/re re A7645749
Ref: 24aa7645749
Ref: library/re re ASCII7645764
Ref: 62f7645764
Ref: library/re re DEBUG7646437
Ref: 24b57646437
Ref: library/re re I7646552
Ref: 24ab7646552
Ref: library/re re IGNORECASE7646567
Ref: 18377646567
Ref: library/re re L7647555
Ref: 24ac7647555
Ref: library/re re LOCALE7647570
Ref: b887647570
Ref: library/re re M7648555
Ref: 24ad7648555
Ref: library/re re MULTILINE7648570
Ref: 24a97648570
Ref: library/re re NOFLAG7649160
Ref: 24b67649160
Ref: library/re re S7649551
Ref: 24ae7649551
Ref: library/re re DOTALL7649566
Ref: 24a87649566
Ref: library/re re U7649807
Ref: 24af7649807
Ref: library/re re UNICODE7649822
Ref: b897649822
Ref: library/re re X7650118
Ref: 24b07650118
Ref: library/re re VERBOSE7650133
Ref: 24b77650133
Node: Functions<2>7651205
Ref: library/re functions7651305
Ref: 24b87651305
Ref: library/re re compile7651342
Ref: bf47651342
Ref: library/re re search7652479
Ref: 12727652479
Ref: library/re re match7653069
Ref: 12737653069
Ref: library/re re fullmatch7653913
Ref: fbe7653913
Ref: library/re re split7654435
Ref: 2a27654435
Ref: library/re re findall7656714
Ref: 10657656714
Ref: library/re re finditer7657943
Ref: 15497657943
Ref: library/re re sub7658578
Ref: 2a37658578
Ref: library/re re subn7662351
Ref: 2a47662351
Ref: library/re re escape7662733
Ref: c297662733
Ref: library/re re purge7664221
Ref: 24bc7664221
Node: Exceptions<3>7664290
Ref: library/re exceptions7664376
Ref: 24bd7664376
Ref: library/re re PatternError7664415
Ref: 23e7664415
Ref: library/re re PatternError msg7664868
Ref: e7f7664868
Ref: library/re re PatternError pattern7664935
Ref: e807664935
Ref: library/re re PatternError pos7665007
Ref: e817665007
Ref: library/re re PatternError lineno7665122
Ref: e827665122
Ref: library/re re PatternError colno7665214
Ref: e837665214
Node: Regular Expression Objects7665514
Ref: library/re re-objects7665659
Ref: fc07665659
Ref: library/re regular-expression-objects7665659
Ref: 24be7665659
Ref: library/re re Pattern7665730
Ref: 190d7665730
Ref: library/re re Pattern search7666000
Ref: 24ba7666000
Ref: library/re re Pattern match7667457
Ref: 24b97667457
Ref: library/re re Pattern fullmatch7668308
Ref: fbf7668308
Ref: library/re re Pattern split7669100
Ref: 24bf7669100
Ref: library/re re Pattern findall7669234
Ref: 24c07669234
Ref: library/re re Pattern finditer7669497
Ref: 24c17669497
Ref: library/re re Pattern sub7669762
Ref: 24c27669762
Ref: library/re re Pattern subn7669895
Ref: 24c37669895
Ref: library/re re Pattern flags7670030
Ref: 24c47670030
Ref: library/re re Pattern groups7670303
Ref: 24c57670303
Ref: library/re re Pattern groupindex7670387
Ref: 24c67670387
Ref: library/re re Pattern pattern7670601
Ref: 24c77670601
Node: Match Objects7670860
Ref: library/re id37671017
Ref: 24c87671017
Ref: library/re match-objects7671017
Ref: fc17671017
Ref: library/re re Match7671369
Ref: cee7671369
Ref: library/re re Match expand7671625
Ref: 24c97671625
Ref: library/re re Match group7672221
Ref: 10667672221
Ref: library/re re Match __getitem__7674474
Ref: 24ca7674474
Ref: library/re re Match groups7675176
Ref: 10677675176
Ref: library/re re Match groupdict7676022
Ref: 24cb7676022
Ref: library/re re Match start7676489
Ref: 24cc7676489
Ref: library/re re Match end7676523
Ref: 24cd7676523
Ref: library/re re Match span7677571
Ref: 24ce7677571
Ref: library/re re Match pos7677824
Ref: 24cf7677824
Ref: library/re re Match endpos7678084
Ref: 24d07678084
Ref: library/re re Match lastindex7678338
Ref: 24d17678338
Ref: library/re re Match lastgroup7678737
Ref: 24d27678737
Ref: library/re re Match re7678910
Ref: 24d37678910
Ref: library/re re Match string7679077
Ref: 24d47679077
Node: Regular Expression Examples7679315
Ref: library/re re-examples7679437
Ref: 12a47679437
Ref: library/re regular-expression-examples7679437
Ref: 24d57679437
Node: Checking for a Pair7679781
Ref: library/re checking-for-a-pair7679889
Ref: 24d67679889
Node: Simulating scanf7681986
Ref: library/re simulating-scanf7682118
Ref: 24d77682118
Node: search vs match7684188
Ref: library/re id47684319
Ref: 24d87684319
Ref: library/re search-vs-match7684319
Ref: 24bb7684319
Node: Making a Phonebook7685773
Ref: library/re making-a-phonebook7685900
Ref: 24d97685900
Node: Text Munging7688099
Ref: library/re text-munging7688230
Ref: 24da7688230
Node: Finding all Adverbs7689057
Ref: library/re finding-all-adverbs7689209
Ref: 24db7689209
Node: Finding all Adverbs and their Positions7689662
Ref: library/re finding-all-adverbs-and-their-positions7689821
Ref: 24dc7689821
Node: Raw String Notation7690518
Ref: library/re raw-string-notation7690677
Ref: 24dd7690677
Node: Writing a Tokenizer7691604
Ref: library/re writing-a-tokenizer7691715
Ref: 24de7691715
Ref: library/re frie097695086
Ref: 24a67695086
Ref: Writing a Tokenizer-Footnote-17695366
Node: difflib — Helpers for computing deltas7695421
Ref: library/difflib doc7695614
Ref: 24df7695614
Ref: library/difflib difflib-helpers-for-computing-deltas7695614
Ref: 24e07695614
Ref: library/difflib module-difflib7695614
Ref: 377695614
Ref: library/difflib translation-repo7695614
Ref: 24e17695614
Ref: library/difflib difflib Differ7698117
Ref: 24e27698117
Ref: library/difflib difflib HtmlDiff7699294
Ref: 16637699294
Ref: library/difflib difflib HtmlDiff __init__7699664
Ref: 24e37699664
Ref: library/difflib difflib HtmlDiff make_file7700447
Ref: e217700447
Ref: library/difflib difflib HtmlDiff make_table7702130
Ref: 24e57702130
Ref: library/difflib difflib context_diff7702591
Ref: 24e67702591
Ref: library/difflib difflib get_close_matches7704637
Ref: 24e97704637
Ref: library/difflib difflib ndiff7705801
Ref: 24e47705801
Ref: library/difflib difflib restore7707366
Ref: 24ec7707366
Ref: library/difflib difflib unified_diff7708109
Ref: 24ee7708109
Ref: library/difflib difflib diff_bytes7710034
Ref: e227710034
Ref: library/difflib difflib IS_LINE_JUNK7710928
Ref: 24ea7710928
Ref: library/difflib difflib IS_CHARACTER_JUNK7711230
Ref: 24eb7711230
Ref: difflib — Helpers for computing deltas-Footnote-17711900
Ref: difflib — Helpers for computing deltas-Footnote-27711967
Node: SequenceMatcher objects7712047
Ref: library/difflib sequence-matcher7712180
Ref: 24ef7712180
Ref: library/difflib sequencematcher-objects7712180
Ref: 24f07712180
Ref: library/difflib difflib SequenceMatcher7712307
Ref: 10547712307
Ref: library/difflib difflib SequenceMatcher set_seqs7713836
Ref: 24f17713836
Ref: library/difflib difflib SequenceMatcher set_seq17714248
Ref: 24f37714248
Ref: library/difflib difflib SequenceMatcher set_seq27714391
Ref: 24f27714391
Ref: library/difflib difflib SequenceMatcher find_longest_match7714534
Ref: 1af27714534
Ref: library/difflib difflib SequenceMatcher get_matching_blocks7716684
Ref: 24f47716684
Ref: library/difflib difflib SequenceMatcher get_opcodes7717601
Ref: 24f57717601
Ref: library/difflib difflib SequenceMatcher get_grouped_opcodes7719588
Ref: 24f67719588
Ref: library/difflib difflib SequenceMatcher ratio7720021
Ref: 24f77720021
Ref: library/difflib difflib SequenceMatcher quick_ratio7721037
Ref: 24f87721037
Ref: library/difflib difflib SequenceMatcher real_quick_ratio7721157
Ref: 24f97721157
Node: SequenceMatcher examples7721689
Ref: library/difflib id17721845
Ref: 24fa7721845
Ref: library/difflib sequencematcher-examples7721845
Ref: 24fb7721845
Ref: SequenceMatcher examples-Footnote-17723580
Node: Differ objects7723657
Ref: library/difflib differ-objects7723804
Ref: 24fc7723804
Ref: library/difflib id27723804
Ref: 24fd7723804
Ref: library/difflib difflib Differ compare7725198
Ref: 24ed7725198
Node: Differ example7725722
Ref: library/difflib differ-example7725880
Ref: 24fe7725880
Ref: library/difflib differ-examples7725880
Ref: 24ff7725880
Node: A command-line interface to difflib7728145
Ref: library/difflib a-command-line-interface-to-difflib7728302
Ref: 25007728302
Ref: library/difflib difflib-interface7728302
Ref: 24e87728302
Node: ndiff example7730932
Ref: library/difflib ndiff-example7731066
Ref: 25017731066
Node: textwrap — Text wrapping and filling7734716
Ref: library/textwrap doc7734905
Ref: 25027734905
Ref: library/textwrap module-textwrap7734905
Ref: ec7734905
Ref: library/textwrap textwrap-text-wrapping-and-filling7734905
Ref: 25037734905
Ref: library/textwrap translation-repo7734905
Ref: 25047734905
Ref: library/textwrap textwrap wrap7735426
Ref: 15167735426
Ref: library/textwrap textwrap fill7736157
Ref: 15157736157
Ref: library/textwrap textwrap shorten7736770
Ref: 100b7736770
Ref: library/textwrap textwrap dedent7738008
Ref: 250a7738008
Ref: library/textwrap textwrap indent7738944
Ref: 2767738944
Ref: library/textwrap textwrap TextWrapper7740265
Ref: 10087740265
Ref: library/textwrap textwrap TextWrapper width7740922
Ref: 250c7740922
Ref: library/textwrap textwrap TextWrapper expand_tabs7741231
Ref: 25077741231
Ref: library/textwrap textwrap TextWrapper tabsize7741441
Ref: 25067741441
Ref: library/textwrap textwrap TextWrapper replace_whitespace7741731
Ref: 25097741731
Ref: library/textwrap textwrap TextWrapper drop_whitespace7742694
Ref: 25087742694
Ref: library/textwrap textwrap TextWrapper initial_indent7743108
Ref: 250d7743108
Ref: library/textwrap textwrap TextWrapper subsequent_indent7743343
Ref: 250e7743343
Ref: library/textwrap textwrap TextWrapper fix_sentence_endings7743570
Ref: 250f7743570
Ref: library/textwrap textwrap TextWrapper break_long_words7744772
Ref: 250b7744772
Ref: library/textwrap textwrap TextWrapper break_on_hyphens7745233
Ref: 25107745233
Ref: library/textwrap textwrap TextWrapper max_lines7745765
Ref: 10097745765
Ref: library/textwrap textwrap TextWrapper placeholder7746012
Ref: 100a7746012
Ref: library/textwrap textwrap TextWrapper wrap7746322
Ref: 25057746322
Ref: library/textwrap textwrap TextWrapper fill7746738
Ref: 25117746738
Ref: textwrap — Text wrapping and filling-Footnote-17746925
Node: unicodedata — Unicode Database7746993
Ref: library/unicodedata doc7747184
Ref: 25127747184
Ref: library/unicodedata module-unicodedata7747184
Ref: 1057747184
Ref: library/unicodedata translation-repo7747184
Ref: 25137747184
Ref: library/unicodedata unicodedata-unicode-database7747184
Ref: 25147747184
Ref: library/unicodedata unicodedata lookup7747820
Ref: 10b67747820
Ref: library/unicodedata unicodedata name7748449
Ref: 25157748449
Ref: library/unicodedata unicodedata decimal7748844
Ref: 25167748844
Ref: library/unicodedata unicodedata digit7749260
Ref: 25177749260
Ref: library/unicodedata unicodedata numeric7749573
Ref: 12a97749573
Ref: library/unicodedata unicodedata category7749874
Ref: 25187749874
Ref: library/unicodedata unicodedata bidirectional7750274
Ref: 25197750274
Ref: library/unicodedata unicodedata combining7750733
Ref: 251a7750733
Ref: library/unicodedata unicodedata east_asian_width7751038
Ref: 251b7751038
Ref: library/unicodedata unicodedata mirrored7751262
Ref: 251c7751262
Ref: library/unicodedata unicodedata decomposition7751592
Ref: 15b17751592
Ref: library/unicodedata unicodedata normalize7751890
Ref: 6d87751890
Ref: library/unicodedata unicodedata is_normalized7753762
Ref: a557753762
Ref: library/unicodedata unicodedata unidata_version7754071
Ref: 251d7754071
Ref: library/unicodedata unicodedata ucd_3_2_07754173
Ref: 14827754173
Ref: unicodedata — Unicode Database-Footnote-17754472
Ref: unicodedata — Unicode Database-Footnote-27754522
Ref: unicodedata — Unicode Database-Footnote-37754568
Ref: unicodedata — Unicode Database-Footnote-47754640
Ref: unicodedata — Unicode Database-Footnote-57754715
Ref: unicodedata — Unicode Database-Footnote-67754798
Ref: unicodedata — Unicode Database-Footnote-77754875
Ref: unicodedata — Unicode Database-Footnote-87754967
Node: stringprep — Internet String Preparation7755025
Ref: library/stringprep doc7755213
Ref: 251e7755213
Ref: library/stringprep module-stringprep7755213
Ref: d47755213
Ref: library/stringprep stringprep-internet-string-preparation7755213
Ref: 251f7755213
Ref: library/stringprep translation-repo7755213
Ref: 25207755213
Ref: library/stringprep stringprep in_table_a17757120
Ref: 25217757120
Ref: library/stringprep stringprep in_table_b17757257
Ref: 25227757257
Ref: library/stringprep stringprep map_table_b27757383
Ref: 25237757383
Ref: library/stringprep stringprep map_table_b37757540
Ref: 25247757540
Ref: library/stringprep stringprep in_table_c117757709
Ref: 25257757709
Ref: library/stringprep stringprep in_table_c127757829
Ref: 25267757829
Ref: library/stringprep stringprep in_table_c11_c127757958
Ref: 25277757958
Ref: library/stringprep stringprep in_table_c217758105
Ref: 25287758105
Ref: library/stringprep stringprep in_table_c227758232
Ref: 25297758232
Ref: library/stringprep stringprep in_table_c21_c227758363
Ref: 252a7758363
Ref: library/stringprep stringprep in_table_c37758512
Ref: 252b7758512
Ref: library/stringprep stringprep in_table_c47758618
Ref: 252c7758618
Ref: library/stringprep stringprep in_table_c57758743
Ref: 252d7758743
Ref: library/stringprep stringprep in_table_c67758853
Ref: 252e7758853
Ref: library/stringprep stringprep in_table_c77758981
Ref: 252f7758981
Ref: library/stringprep stringprep in_table_c87759123
Ref: 25307759123
Ref: library/stringprep stringprep in_table_c97759266
Ref: 25317759266
Ref: library/stringprep stringprep in_table_d17759379
Ref: 25327759379
Ref: library/stringprep stringprep in_table_d27759537
Ref: 25337759537
Ref: stringprep — Internet String Preparation-Footnote-17759719
Ref: stringprep — Internet String Preparation-Footnote-27759789
Ref: stringprep — Internet String Preparation-Footnote-37759848
Node: readline — GNU readline interface7759907
Ref: library/readline doc7760115
Ref: 25347760115
Ref: library/readline module-readline7760115
Ref: ba7760115
Ref: library/readline readline-gnu-readline-interface7760115
Ref: 25357760115
Ref: library/readline translation-repo7760115
Ref: 25367760115
Ref: library/readline readline backend7762221
Ref: 17c07762221
Ref: readline — GNU readline interface-Footnote-17762545
Node: Init file7762630
Ref: library/readline init-file7762731
Ref: 25377762731
Ref: library/readline readline parse_and_bind7762841
Ref: 25387762841
Ref: library/readline readline read_init_file7763022
Ref: 25397763022
Node: Line buffer7763244
Ref: library/readline line-buffer7763366
Ref: 253a7763366
Ref: library/readline readline get_line_buffer7763460
Ref: 253b7763460
Ref: library/readline readline insert_text7763611
Ref: 253c7763611
Ref: library/readline readline redisplay7763821
Ref: 15147763821
Node: History file7764026
Ref: library/readline history-file7764151
Ref: 253d7764151
Ref: library/readline readline read_history_file7764246
Ref: 253e7764246
Ref: library/readline readline write_history_file7764484
Ref: 253f7764484
Ref: library/readline readline append_history_file7764741
Ref: e857764741
Ref: library/readline readline get_history_length7765150
Ref: 25407765150
Ref: library/readline readline set_history_length7765195
Ref: 16ff7765195
Node: History list7765558
Ref: library/readline history-list7765685
Ref: 25417765685
Ref: library/readline readline clear_history7765787
Ref: 25427765787
Ref: library/readline readline get_current_history_length7766035
Ref: 15137766035
Ref: library/readline readline get_history_item7766300
Ref: 15127766300
Ref: library/readline readline remove_history_item7766510
Ref: 25437766510
Ref: library/readline readline replace_history_item7766730
Ref: 25447766730
Ref: library/readline readline add_history7766961
Ref: 25457766961
Ref: library/readline readline set_auto_history7767145
Ref: cf07767145
Node: Startup hooks7767613
Ref: library/readline startup-hooks7767738
Ref: 25467767738
Ref: library/readline readline set_startup_hook7767783
Ref: 25477767783
Ref: library/readline readline set_pre_input_hook7768187
Ref: 25487768187
Node: Completion7768759
Ref: library/readline completion7768879
Ref: 25497768879
Ref: library/readline readline-completion7768879
Ref: 254a7768879
Ref: library/readline readline set_completer7769360
Ref: 254b7769360
Ref: library/readline readline get_completer7770151
Ref: 254c7770151
Ref: library/readline readline get_completion_type7770284
Ref: 254d7770284
Ref: library/readline readline get_begidx7770484
Ref: 1a4a7770484
Ref: library/readline readline get_endidx7770521
Ref: 1a4b7770521
Ref: library/readline readline set_completer_delims7770966
Ref: 17c37770966
Ref: library/readline readline get_completer_delims7771019
Ref: 254e7771019
Ref: library/readline readline set_completion_display_matches_hook7771340
Ref: 254f7771340
Node: Example7771929
Ref: library/readline example7772027
Ref: 25507772027
Ref: library/readline readline-example7772027
Ref: 25517772027
Node: rlcompleter — Completion function for GNU readline7774870
Ref: library/rlcompleter doc7775027
Ref: 25537775027
Ref: library/rlcompleter module-rlcompleter7775027
Ref: bd7775027
Ref: library/rlcompleter rlcompleter-completion-function-for-gnu-readline7775027
Ref: 25547775027
Ref: library/rlcompleter translation-repo7775027
Ref: 25557775027
Ref: library/rlcompleter completer-objects7776517
Ref: 25577776517
Ref: library/rlcompleter rlcompleter Completer7776517
Ref: 1ad27776517
Ref: library/rlcompleter rlcompleter Completer complete7776602
Ref: 25567776602
Ref: rlcompleter — Completion function for GNU readline-Footnote-17777641
Node: Binary Data Services7777712
Ref: library/binary doc7777848
Ref: 25587777848
Ref: library/binary binary-data-services7777848
Ref: 25597777848
Ref: library/binary binaryservices7777848
Ref: 24767777848
Ref: library/binary translation-repo7777848
Ref: 255a7777848
Node: struct — Interpret bytes as packed binary data7778614
Ref: library/struct doc7778770
Ref: 255b7778770
Ref: library/struct struct-interpret-bytes-as-packed-binary-data7778770
Ref: 255c7778770
Ref: library/struct module-struct7778887
Ref: d57778887
Ref: struct — Interpret bytes as packed binary data-Footnote-17780651
Node: Functions and Exceptions7780717
Ref: library/struct functions-and-exceptions7780849
Ref: 255f7780849
Ref: library/struct struct error7780975
Ref: 136d7780975
Ref: library/struct struct pack7781101
Ref: 12bd7781101
Ref: library/struct struct pack_into7781343
Ref: 25607781343
Ref: library/struct struct unpack7781642
Ref: 18f67781642
Ref: library/struct struct unpack_from7782009
Ref: 25617782009
Ref: library/struct struct iter_unpack7782405
Ref: ff87782405
Ref: library/struct struct calcsize7782927
Ref: 1b547782927
Node: Format Strings7783126
Ref: library/struct format-strings7783279
Ref: 25627783279
Ref: library/struct struct-format-strings7783279
Ref: 255d7783279
Node: Byte Order Size and Alignment7783917
Ref: library/struct byte-order-size-and-alignment7784023
Ref: 25647784023
Ref: library/struct struct-alignment7784023
Ref: 255e7784023
Ref: Byte Order Size and Alignment-Footnote-17787739
Node: Format Characters7787793
Ref: library/struct format-characters7787919
Ref: 25637787919
Ref: library/struct id17787919
Ref: 25667787919
Ref: Format Characters-Footnote-17799539
Ref: Format Characters-Footnote-27799600
Node: Examples<2>7799676
Ref: library/struct examples7799764
Ref: 25677799764
Ref: library/struct struct-examples7799764
Ref: 25657799764
Node: Applications7802272
Ref: library/struct applications7802411
Ref: 25687802411
Ref: library/struct id27802411
Ref: 25697802411
Node: Native Formats7802912
Ref: library/struct native-formats7803000
Ref: 256c7803000
Ref: library/struct struct-native-formats7803000
Ref: 256a7803000
Node: Standard Formats7804148
Ref: library/struct standard-formats7804236
Ref: 256d7804236
Ref: library/struct struct-standard-formats7804236
Ref: 256b7804236
Node: Classes<3>7805679
Ref: library/struct classes7805795
Ref: 256e7805795
Ref: library/struct struct-objects7805795
Ref: 256f7805795
Ref: library/struct struct Struct7805891
Ref: 15ad7805891
Ref: library/struct struct Struct pack7806580
Ref: 25707806580
Ref: library/struct struct Struct pack_into7806762
Ref: 25727806762
Ref: library/struct struct Struct unpack7806920
Ref: 25737806920
Ref: library/struct struct Struct unpack_from7807120
Ref: 25747807120
Ref: library/struct struct Struct iter_unpack7807378
Ref: ff97807378
Ref: library/struct struct Struct format7807631
Ref: c267807631
Ref: library/struct struct Struct size7807846
Ref: 25717807846
Node: codecs — Codec registry and base classes7808182
Ref: library/codecs doc7808338
Ref: 25757808338
Ref: library/codecs codecs-codec-registry-and-base-classes7808338
Ref: 25767808338
Ref: library/codecs module-codecs7808338
Ref: 1b7808338
Ref: library/codecs translation-repo7808338
Ref: 25777808338
Ref: library/codecs codecs encode7809217
Ref: f387809217
Ref: library/codecs codecs decode7809712
Ref: f397809712
Ref: library/codecs codecs charmap_build7810207
Ref: 25797810207
Ref: library/codecs codecs lookup7810700
Ref: 96d7810700
Ref: library/codecs codecs CodecInfo7811191
Ref: 180b7811191
Ref: library/codecs codecs CodecInfo name7811487
Ref: 257a7811487
Ref: library/codecs codecs CodecInfo encode7811550
Ref: 257b7811550
Ref: library/codecs codecs CodecInfo decode7811577
Ref: 257c7811577
Ref: library/codecs codecs CodecInfo incrementalencoder7811955
Ref: 25807811955
Ref: library/codecs codecs CodecInfo incrementaldecoder7811994
Ref: 25817811994
Ref: library/codecs codecs CodecInfo streamwriter7812333
Ref: 25847812333
Ref: library/codecs codecs CodecInfo streamreader7812366
Ref: 25857812366
Ref: library/codecs codecs getencoder7812819
Ref: 25887812819
Ref: library/codecs codecs getdecoder7813031
Ref: 25897813031
Ref: library/codecs codecs getincrementalencoder7813243
Ref: 258a7813243
Ref: library/codecs codecs getincrementaldecoder7813549
Ref: 258b7813549
Ref: library/codecs codecs getreader7813855
Ref: 258c7813855
Ref: library/codecs codecs getwriter7814101
Ref: 258d7814101
Ref: library/codecs codecs register7814430
Ref: 258e7814430
Ref: library/codecs codecs unregister7814905
Ref: 7ed7814905
Ref: library/codecs codecs open7815403
Ref: 7437815403
Ref: library/codecs codecs EncodedFile7816754
Ref: 25907816754
Ref: library/codecs codecs iterencode7817611
Ref: 25917817611
Ref: library/codecs codecs iterdecode7818196
Ref: 25927818196
Ref: library/codecs codecs readbuffer_encode7818855
Ref: 25937818855
Ref: library/codecs codecs BOM7819356
Ref: 25947819356
Ref: library/codecs codecs BOM_BE7819377
Ref: 25957819377
Ref: library/codecs codecs BOM_LE7819401
Ref: 25967819401
Ref: library/codecs codecs BOM_UTF87819425
Ref: 25977819425
Ref: library/codecs codecs BOM_UTF167819451
Ref: 25987819451
Ref: library/codecs codecs BOM_UTF16_BE7819478
Ref: 25997819478
Ref: library/codecs codecs BOM_UTF16_LE7819508
Ref: 259a7819508
Ref: library/codecs codecs BOM_UTF327819538
Ref: 259b7819538
Ref: library/codecs codecs BOM_UTF32_BE7819565
Ref: 259c7819565
Ref: library/codecs codecs BOM_UTF32_LE7819595
Ref: 259d7819595
Ref: codecs — Codec registry and base classes-Footnote-17820759
Node: Codec Base Classes7820825
Ref: library/codecs codec-base-classes7820952
Ref: 25787820952
Ref: library/codecs id17820952
Ref: 259e7820952
Ref: library/codecs surrogateescape7821540
Ref: 259f7821540
Node: Error Handlers7821677
Ref: library/codecs error-handlers7821786
Ref: 19157821786
Ref: library/codecs id27821786
Ref: 25a07821786
Ref: library/codecs codecs register_error7826706
Ref: 14ea7826706
Ref: library/codecs codecs lookup_error7828248
Ref: 14eb7828248
Ref: library/codecs codecs strict_errors7828543
Ref: 25a17828543
Ref: library/codecs codecs ignore_errors7828716
Ref: 25a27828716
Ref: library/codecs codecs replace_errors7828912
Ref: 25a37828912
Ref: library/codecs codecs backslashreplace_errors7829162
Ref: 25a47829162
Ref: library/codecs codecs xmlcharrefreplace_errors7829624
Ref: 25a57829624
Ref: library/codecs codecs namereplace_errors7829988
Ref: 25a67829988
Ref: Error Handlers-Footnote-17830551
Node: Stateless Encoding and Decoding7830593
Ref: library/codecs codec-objects7830744
Ref: 257f7830744
Ref: library/codecs stateless-encoding-and-decoding7830744
Ref: 25a77830744
Ref: library/codecs codecs Codec7830962
Ref: 25a87830962
Ref: library/codecs codecs Codec encode7830987
Ref: 257d7830987
Ref: library/codecs codecs Codec decode7831800
Ref: 257e7831800
Node: Incremental Encoding and Decoding7832823
Ref: library/codecs incremental-encoding-and-decoding7832988
Ref: 25a97832988
Node: IncrementalEncoder Objects7833828
Ref: library/codecs incremental-encoder-objects7833959
Ref: 25ac7833959
Ref: library/codecs incrementalencoder-objects7833959
Ref: 25ad7833959
Ref: library/codecs codecs IncrementalEncoder7834258
Ref: 25827834258
Ref: library/codecs codecs IncrementalEncoder encode7835022
Ref: 25aa7835022
Ref: library/codecs codecs IncrementalEncoder reset7835313
Ref: 25ae7835313
Ref: library/codecs codecs IncrementalEncoder getstate7835582
Ref: 25af7835582
Ref: library/codecs codecs IncrementalEncoder setstate7835995
Ref: 25b07835995
Node: IncrementalDecoder Objects7836162
Ref: library/codecs incremental-decoder-objects7836293
Ref: 25b17836293
Ref: library/codecs incrementaldecoder-objects7836293
Ref: 25b27836293
Ref: library/codecs codecs IncrementalDecoder7836592
Ref: 25837836592
Ref: library/codecs codecs IncrementalDecoder decode7837356
Ref: 25ab7837356
Ref: library/codecs codecs IncrementalDecoder reset7837973
Ref: 25b37837973
Ref: library/codecs codecs IncrementalDecoder getstate7838051
Ref: 25b47838051
Ref: library/codecs codecs IncrementalDecoder setstate7838998
Ref: 25b57838998
Node: Stream Encoding and Decoding7839164
Ref: library/codecs stream-encoding-and-decoding7839289
Ref: 25b67839289
Node: StreamWriter Objects7839716
Ref: library/codecs stream-writer-objects7839830
Ref: 25b77839830
Ref: library/codecs streamwriter-objects7839830
Ref: 25b87839830
Ref: library/codecs codecs StreamWriter7840092
Ref: 25867840092
Ref: library/codecs codecs StreamWriter write7841028
Ref: 25b97841028
Ref: library/codecs codecs StreamWriter writelines7841126
Ref: 25ba7841126
Ref: library/codecs codecs StreamWriter reset7841432
Ref: 25bb7841432
Node: StreamReader Objects7841901
Ref: library/codecs stream-reader-objects7842050
Ref: 25bc7842050
Ref: library/codecs streamreader-objects7842050
Ref: 25bd7842050
Ref: library/codecs codecs StreamReader7842312
Ref: 25877842312
Ref: library/codecs codecs StreamReader read7843362
Ref: 25be7843362
Ref: library/codecs codecs StreamReader readline7844620
Ref: 25bf7844620
Ref: library/codecs codecs StreamReader readlines7844971
Ref: 25c07844971
Ref: library/codecs codecs StreamReader reset7845422
Ref: 25c17845422
Node: StreamReaderWriter Objects7845825
Ref: library/codecs stream-reader-writer7845975
Ref: 25c27845975
Ref: library/codecs streamreaderwriter-objects7845975
Ref: 25c37845975
Ref: library/codecs codecs StreamReaderWriter7846310
Ref: 258f7846310
Node: StreamRecoder Objects7846958
Ref: library/codecs stream-recoder-objects7847079
Ref: 25c47847079
Ref: library/codecs streamrecoder-objects7847079
Ref: 25c57847079
Ref: library/codecs codecs StreamRecoder7847429
Ref: 1b817847429
Node: Encodings and Unicode7848576
Ref: library/codecs encodings-and-unicode7848730
Ref: 25c67848730
Ref: library/codecs encodings-overview7848730
Ref: 25c77848730
Ref: Encodings and Unicode-Footnote-17855656
Node: Standard Encodings7855698
Ref: library/codecs id37855859
Ref: 25c87855859
Ref: library/codecs standard-encodings7855859
Ref: de77855859
Ref: Standard Encodings-Footnote-17878165
Node: Python Specific Encodings7878243
Ref: library/codecs python-specific-encodings7878414
Ref: 25c97878414
Node: Text Encodings7879033
Ref: library/codecs text-encodings7879135
Ref: 25ca7879135
Ref: Text Encodings-Footnote-17882674
Ref: Text Encodings-Footnote-27882733
Node: Binary Transforms7882792
Ref: library/codecs binary-transforms7882929
Ref: f3a7882929
Ref: library/codecs id47882929
Ref: 25cb7882929
Ref: Binary Transforms-Footnote-17886615
Node: Standalone Codec Functions7886756
Ref: library/codecs id67886894
Ref: 25d17886894
Ref: library/codecs standalone-codec-functions7886894
Ref: 25d27886894
Ref: library/codecs codecs codecs escape_encode7887306
Ref: 25d37887306
Ref: library/codecs codecs codecs escape_decode7887678
Ref: 25d47887678
Node: Text Transforms7888001
Ref: library/codecs id77888113
Ref: 25d57888113
Ref: library/codecs text-transforms7888113
Ref: f3b7888113
Node: encodings — Encodings package7888853
Ref: library/codecs encodings-encodings-package7889071
Ref: 25d67889071
Ref: library/codecs module-encodings7889071
Ref: 517889071
Ref: library/codecs encodings normalize_encoding7889209
Ref: 8017889209
Ref: library/codecs encodings search_function7889785
Ref: 15ac7889785
Ref: library/codecs encodings CodecRegistryError7890529
Ref: 25d77890529
Node: encodings idna — Internationalized Domain Names in Applications7890628
Ref: library/codecs encodings-idna-internationalized-domain-names-in-applications7890861
Ref: 25d87890861
Ref: library/codecs module-encodings idna7890861
Ref: 527890861
Ref: library/codecs encodings idna nameprep7893466
Ref: 25d97893466
Ref: library/codecs encodings idna ToASCII7893654
Ref: 25da7893654
Ref: library/codecs encodings idna ToUnicode7893814
Ref: 25db7893814
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-17893961
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-27894020
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-37894079
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-47894138
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-57894197
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-67894236
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-77894307
Ref: encodings idna — Internationalized Domain Names in Applications-Footnote-87894366
Node: encodings mbcs — Windows ANSI codepage7894425
Ref: library/codecs encodings-mbcs-windows-ansi-codepage7894681
Ref: 25dc7894681
Ref: library/codecs module-encodings mbcs7894681
Ref: 537894681
Node: encodings utf_8_sig — UTF-8 codec with BOM signature7895074
Ref: library/codecs encodings-utf-8-sig-utf-8-codec-with-bom-signature7895256
Ref: 25dd7895256
Ref: library/codecs module-encodings utf_8_sig7895256
Ref: 547895256
Node: Data Types7895701
Ref: library/datatypes doc7895845
Ref: 25de7895845
Ref: library/datatypes data-types7895845
Ref: 25df7895845
Ref: library/datatypes datatypes7895845
Ref: 25e07895845
Ref: library/datatypes translation-repo7895845
Ref: 25e17895845
Node: datetime — Basic date and time types7897224
Ref: library/datetime doc7897353
Ref: 25e27897353
Ref: library/datetime datetime-basic-date-and-time-types7897353
Ref: 25e37897353
Ref: library/datetime module-datetime7897353
Ref: 307897353
Ref: datetime — Basic date and time types-Footnote-17898661
Ref: datetime — Basic date and time types-Footnote-27898729
Ref: datetime — Basic date and time types-Footnote-37898780
Node: Aware and Naive Objects7898823
Ref: library/datetime aware-and-naive-objects7898939
Ref: 25e57898939
Ref: library/datetime datetime-naive-aware7898939
Ref: 25e67898939
Ref: Aware and Naive Objects-Footnote-17900855
Node: Constants7900913
Ref: library/datetime constants7901053
Ref: 25e77901053
Ref: library/datetime datetime MINYEAR7901150
Ref: 25e87901150
Ref: library/datetime datetime MAXYEAR7901304
Ref: 25e97901304
Ref: library/datetime datetime UTC7901460
Ref: 4f17901460
Node: Available Types7901596
Ref: library/datetime available-types7901730
Ref: 25ea7901730
Node: Common Properties7903492
Ref: library/datetime common-properties7903612
Ref: 25fb7903612
Node: Determining if an Object is Aware or Naive7904034
Ref: library/datetime determining-if-an-object-is-aware-or-naive7904154
Ref: 25fc7904154
Node: timedelta Objects7904905
Ref: library/datetime datetime-timedelta7905042
Ref: 25fd7905042
Ref: library/datetime timedelta-objects7905042
Ref: 25fe7905042
Ref: library/datetime datetime timedelta7905237
Ref: 9da7905237
Ref: library/datetime datetime timedelta min7908205
Ref: 25ff7908205
Ref: library/datetime datetime timedelta max7908323
Ref: 26007908323
Ref: library/datetime datetime timedelta resolution7908505
Ref: 26017908505
Ref: library/datetime datetime timedelta days7908876
Ref: 26027908876
Ref: library/datetime datetime timedelta seconds7908961
Ref: 26037908961
Ref: library/datetime datetime timedelta microseconds7909481
Ref: 26047909481
Ref: library/datetime datetime timedelta total_seconds7915393
Ref: 134f7915393
Ref: timedelta Objects-Footnote-17915953
Node: Examples of usage timedelta7916033
Ref: library/datetime examples-of-usage-timedelta7916114
Ref: 26057916114
Node: date Objects7917049
Ref: library/datetime date-objects7917187
Ref: 26067917187
Ref: library/datetime datetime-date7917187
Ref: 26077917187
Ref: library/datetime datetime date7917509
Ref: 1cd7917509
Ref: library/datetime datetime date today7917928
Ref: 15197917928
Ref: library/datetime datetime date fromtimestamp7918071
Ref: bf37918071
Ref: library/datetime datetime date fromordinal7918997
Ref: bf27918997
Ref: library/datetime datetime date fromisoformat7919334
Ref: 6187919334
Ref: library/datetime datetime date fromisocalendar7920248
Ref: 9f77920248
Ref: library/datetime datetime date min7920541
Ref: 26087920541
Ref: library/datetime datetime date max7920632
Ref: 26097920632
Ref: library/datetime datetime date resolution7920723
Ref: 260a7920723
Ref: library/datetime datetime date year7920890
Ref: 25eb7920890
Ref: library/datetime datetime date month7920987
Ref: 25ec7920987
Ref: library/datetime datetime date day7921048
Ref: 25ed7921048
Ref: library/datetime datetime date replace7923887
Ref: 17907923887
Ref: library/datetime datetime date timetuple7924342
Ref: 260b7924342
Ref: library/datetime datetime date toordinal7924831
Ref: 260c7924831
Ref: library/datetime datetime date weekday7925057
Ref: 260d7925057
Ref: library/datetime datetime date isoweekday7925282
Ref: 260e7925282
Ref: library/datetime datetime date isocalendar7925541
Ref: 8fe7925541
Ref: library/datetime datetime date isoformat7926618
Ref: 260f7926618
Ref: library/datetime datetime date __str__7926843
Ref: 26107926843
Ref: library/datetime datetime date ctime7926949
Ref: 26117926949
Ref: library/datetime datetime date strftime7927415
Ref: cb67927415
Ref: library/datetime datetime date __format__7927716
Ref: 26137927716
Ref: date Objects-Footnote-17928167
Ref: date Objects-Footnote-27928476
Node: Examples of Usage date7928692
Ref: library/datetime examples-of-usage-date7928763
Ref: 26147928763
Node: datetime Objects7930668
Ref: library/datetime datetime-datetime7930801
Ref: 26157930801
Ref: library/datetime datetime-objects7930801
Ref: 26167930801
Ref: library/datetime datetime datetime7931244
Ref: 1cc7931244
Ref: library/datetime datetime datetime today7932108
Ref: 26177932108
Ref: library/datetime datetime datetime now7932473
Ref: 4ef7932473
Ref: library/datetime datetime datetime utcnow7933301
Ref: 2fc7933301
Ref: library/datetime datetime datetime fromtimestamp7934139
Ref: 4f07934139
Ref: library/datetime datetime datetime utcfromtimestamp7935831
Ref: 2fd7935831
Ref: library/datetime datetime datetime fromordinal7937604
Ref: 26187937604
Ref: library/datetime datetime datetime combine7938009
Ref: cb77938009
Ref: library/datetime datetime datetime fromisoformat7938804
Ref: 61a7938804
Ref: library/datetime datetime datetime fromisocalendar7940923
Ref: 9f87940923
Ref: library/datetime datetime datetime strptime7941303
Ref: 17147941303
Ref: library/datetime datetime datetime min7942756
Ref: 190b7942756
Ref: library/datetime datetime datetime max7942888
Ref: 26197942888
Ref: library/datetime datetime datetime resolution7943040
Ref: 261a7943040
Ref: library/datetime datetime datetime year7943235
Ref: 25f37943235
Ref: library/datetime datetime datetime month7943336
Ref: 25f47943336
Ref: library/datetime datetime datetime day7943401
Ref: 25f57943401
Ref: library/datetime datetime datetime hour7943512
Ref: 25f67943512
Ref: library/datetime datetime datetime minute7943568
Ref: 25f77943568
Ref: library/datetime datetime datetime second7943626
Ref: 25f87943626
Ref: library/datetime datetime datetime microsecond7943684
Ref: 25f97943684
Ref: library/datetime datetime datetime tzinfo7943752
Ref: 25fa7943752
Ref: library/datetime datetime datetime fold7943913
Ref: c787943913
Ref: library/datetime datetime datetime date7948925
Ref: 261b7948925
Ref: library/datetime datetime datetime time7949023
Ref: 261c7949023
Ref: library/datetime datetime datetime timetz7949330
Ref: 261d7949330
Ref: library/datetime datetime datetime replace7949619
Ref: 151a7949619
Ref: library/datetime datetime datetime astimezone7950273
Ref: 9db7950273
Ref: library/datetime datetime datetime utcoffset7952609
Ref: 261e7952609
Ref: library/datetime datetime datetime dst7953003
Ref: 261f7953003
Ref: library/datetime datetime datetime tzname7953385
Ref: 26217953385
Ref: library/datetime datetime datetime timetuple7953618
Ref: 26227953618
Ref: library/datetime datetime datetime utctimetuple7954447
Ref: 26247954447
Ref: library/datetime datetime datetime toordinal7955609
Ref: 26257955609
Ref: library/datetime datetime datetime timestamp7955751
Ref: 10de7955751
Ref: library/datetime datetime datetime weekday7957283
Ref: 26267957283
Ref: library/datetime datetime datetime isoweekday7957487
Ref: 26277957487
Ref: library/datetime datetime datetime isocalendar7957720
Ref: 8ff7957720
Ref: library/datetime datetime datetime isoformat7957912
Ref: b487957912
Ref: library/datetime datetime datetime __str__7960895
Ref: 26287960895
Ref: library/datetime datetime datetime ctime7961038
Ref: 26297961038
Ref: library/datetime datetime datetime strftime7961659
Ref: cb57961659
Ref: library/datetime datetime datetime __format__7961899
Ref: 262a7961899
Node: Examples of Usage datetime7962337
Ref: library/datetime examples-of-usage-datetime7962416
Ref: 262b7962416
Node: time Objects7966825
Ref: library/datetime datetime-time7966960
Ref: 262c7966960
Ref: library/datetime time-objects7966960
Ref: 262d7966960
Ref: library/datetime datetime time7967168
Ref: 1ce7967168
Ref: library/datetime datetime time min7967822
Ref: 262e7967822
Ref: library/datetime datetime time max7967921
Ref: 262f7967921
Ref: library/datetime datetime time resolution7968031
Ref: 26307968031
Ref: library/datetime datetime time hour7968293
Ref: 25ee7968293
Ref: library/datetime datetime time minute7968345
Ref: 25ef7968345
Ref: library/datetime datetime time second7968399
Ref: 25f07968399
Ref: library/datetime datetime time microsecond7968453
Ref: 25f17968453
Ref: library/datetime datetime time tzinfo7968517
Ref: 25f27968517
Ref: library/datetime datetime time fold7968668
Ref: cb47968668
Ref: library/datetime datetime time fromisoformat7970264
Ref: 6197970264
Ref: library/datetime datetime time replace7971873
Ref: 17917971873
Ref: library/datetime datetime time isoformat7972447
Ref: 26317972447
Ref: library/datetime datetime time __str__7974480
Ref: 26337974480
Ref: library/datetime datetime time strftime7974586
Ref: 189b7974586
Ref: library/datetime datetime time __format__7974810
Ref: 26347974810
Ref: library/datetime datetime time utcoffset7975165
Ref: 26327975165
Ref: library/datetime datetime time dst7975555
Ref: 26357975555
Ref: library/datetime datetime time tzname7975934
Ref: 26367975934
Ref: time Objects-Footnote-17976263
Node: Examples of Usage time7976328
Ref: library/datetime examples-of-usage-time7976399
Ref: 26377976399
Node: tzinfo Objects7977277
Ref: library/datetime datetime-tzinfo7977412
Ref: 26387977412
Ref: library/datetime tzinfo-objects7977412
Ref: 26397977412
Ref: library/datetime datetime tzinfo7977469
Ref: 5e17977469
Ref: library/datetime datetime tzinfo utcoffset7979051
Ref: 263a7979051
Ref: library/datetime datetime tzinfo dst7980253
Ref: 263b7980253
Ref: library/datetime datetime tzinfo tzname7982870
Ref: 263c7982870
Ref: library/datetime datetime tzinfo fromutc7984971
Ref: 26207984971
Ref: tzinfo Objects-Footnote-17997693
Node: timezone Objects7997733
Ref: library/datetime datetime-timezone7997886
Ref: 263d7997886
Ref: library/datetime timezone-objects7997886
Ref: 263e7997886
Ref: library/datetime datetime timezone7998309
Ref: 11037998309
Ref: library/datetime datetime timezone utcoffset7998939
Ref: 263f7998939
Ref: library/datetime datetime timezone tzname7999330
Ref: 26407999330
Ref: library/datetime datetime timezone dst8000009
Ref: 26418000009
Ref: library/datetime datetime timezone fromutc8000073
Ref: 26428000073
Ref: library/datetime datetime timezone utc8000268
Ref: 6178000268
Node: strftime and strptime Behavior8000352
Ref: library/datetime strftime-and-strptime-behavior8000482
Ref: 26438000482
Ref: library/datetime strftime-strptime-behavior8000482
Ref: 18f98000482
Ref: library/datetime format-codes8002572
Ref: 25e48002572
Node: strftime and strptime Format Codes8002681
Ref: library/datetime strftime-and-strptime-format-codes8002807
Ref: 26448002807
Ref: strftime and strptime Format Codes-Footnote-18013755
Node: Technical Detail8013803
Ref: library/datetime technical-detail8013929
Ref: 26458013929
Ref: Technical Detail-Footnote-18021722
Node: zoneinfo — IANA time zone support8021777
Ref: library/zoneinfo doc8021962
Ref: 26468021962
Ref: library/zoneinfo module-zoneinfo8021962
Ref: 1348021962
Ref: library/zoneinfo translation-repo8021962
Ref: 26478021962
Ref: library/zoneinfo zoneinfo-iana-time-zone-support8021962
Ref: 26488021962
Ref: zoneinfo — IANA time zone support-Footnote-18023182
Ref: zoneinfo — IANA time zone support-Footnote-28023247
Ref: zoneinfo — IANA time zone support-Footnote-38023289
Ref: zoneinfo — IANA time zone support-Footnote-48023330
Node: Using ZoneInfo8023371
Ref: library/zoneinfo using-zoneinfo8023478
Ref: 26498023478
Ref: Using ZoneInfo-Footnote-18025412
Node: Data sources8025454
Ref: library/zoneinfo data-sources8025588
Ref: 264a8025588
Ref: Data sources-Footnote-18026272
Node: Configuring the data sources8026313
Ref: library/zoneinfo configuring-the-data-sources8026390
Ref: 264b8026390
Ref: library/zoneinfo zoneinfo-data-configuration8026390
Ref: 264c8026390
Node: Compile-time configuration8027143
Ref: library/zoneinfo compile-time-configuration8027268
Ref: 264f8027268
Ref: library/zoneinfo zoneinfo-data-compile-time-config8027268
Ref: 1f188027268
Node: Environment configuration8028003
Ref: library/zoneinfo environment-configuration8028158
Ref: 26508028158
Ref: library/zoneinfo zoneinfo-data-environment-var8028158
Ref: 264d8028158
Ref: library/zoneinfo envvar-PYTHONTZPATH8028477
Ref: 26518028477
Node: Runtime configuration8029138
Ref: library/zoneinfo runtime-configuration8029258
Ref: 26538029258
Ref: library/zoneinfo zoneinfo-data-runtime-config8029258
Ref: 264e8029258
Node: The ZoneInfo class8029626
Ref: library/zoneinfo the-zoneinfo-class8029758
Ref: 26548029758
Ref: library/zoneinfo zoneinfo ZoneInfo8029821
Ref: 8e88029821
Ref: library/zoneinfo zoneinfo ZoneInfo from_file8030701
Ref: 15c78030701
Ref: library/zoneinfo zoneinfo ZoneInfo no_cache8031337
Ref: 26568031337
Ref: library/zoneinfo zoneinfo ZoneInfo clear_cache8032059
Ref: 15b58032059
Ref: library/zoneinfo zoneinfo ZoneInfo key8032856
Ref: 26578032856
Node: String representations8033712
Ref: library/zoneinfo string-representations8033818
Ref: 26598033818
Node: Pickle serialization8034636
Ref: library/zoneinfo pickle-serialization8034742
Ref: 265a8034742
Ref: library/zoneinfo pickling8034742
Ref: 26558034742
Node: Functions<3>8037137
Ref: library/zoneinfo functions8037264
Ref: 265b8037264
Ref: library/zoneinfo zoneinfo available_timezones8037303
Ref: 1aef8037303
Ref: library/zoneinfo zoneinfo reset_tzpath8038279
Ref: 16168038279
Node: Globals8038968
Ref: library/zoneinfo globals8039100
Ref: 265c8039100
Ref: library/zoneinfo zoneinfo TZPATH8039135
Ref: 1f178039135
Node: Exceptions and warnings8039910
Ref: library/zoneinfo exceptions-and-warnings8040021
Ref: 265d8040021
Ref: library/zoneinfo zoneinfo ZoneInfoNotFoundError8040088
Ref: 16318040088
Ref: library/zoneinfo zoneinfo InvalidTZPathWarning8040319
Ref: 26528040319
Node: calendar — General calendar-related functions8040496
Ref: library/calendar doc8040678
Ref: 265e8040678
Ref: library/calendar calendar-general-calendar-related-functions8040678
Ref: 265f8040678
Ref: library/calendar module-calendar8040678
Ref: 148040678
Ref: library/calendar translation-repo8040678
Ref: 26608040678
Ref: library/calendar calendar Calendar8041880
Ref: 26628041880
Ref: library/calendar calendar Calendar firstweekday8042407
Ref: 26658042407
Ref: library/calendar calendar Calendar getfirstweekday8042649
Ref: 26678042649
Ref: library/calendar calendar Calendar setfirstweekday8042834
Ref: 26668042834
Ref: library/calendar calendar Calendar iterweekdays8043054
Ref: 26688043054
Ref: library/calendar calendar Calendar itermonthdates8043303
Ref: c398043303
Ref: library/calendar calendar Calendar itermonthdays8043675
Ref: 26698043675
Ref: library/calendar calendar Calendar itermonthdays28044060
Ref: 266a8044060
Ref: library/calendar calendar Calendar itermonthdays38044410
Ref: c3a8044410
Ref: library/calendar calendar Calendar itermonthdays48044792
Ref: c3b8044792
Ref: library/calendar calendar Calendar monthdatescalendar8045194
Ref: 266b8045194
Ref: library/calendar calendar Calendar monthdays2calendar8045414
Ref: 266c8045414
Ref: library/calendar calendar Calendar monthdayscalendar8045642
Ref: 266d8045642
Ref: library/calendar calendar Calendar yeardatescalendar8045829
Ref: 266e8045829
Ref: library/calendar calendar Calendar yeardays2calendar8046223
Ref: 266f8046223
Ref: library/calendar calendar Calendar yeardayscalendar8046539
Ref: 26708046539
Ref: library/calendar calendar TextCalendar8046824
Ref: 26718046824
Ref: library/calendar calendar TextCalendar formatday8047001
Ref: 26728047001
Ref: library/calendar calendar TextCalendar formatweek8047309
Ref: 26738047309
Ref: library/calendar calendar TextCalendar formatweekday8047654
Ref: 26748047654
Ref: library/calendar calendar TextCalendar formatweekheader8047958
Ref: 26758047958
Ref: library/calendar calendar TextCalendar formatmonth8048232
Ref: 26768048232
Ref: library/calendar calendar TextCalendar formatmonthname8048681
Ref: 26778048681
Ref: library/calendar calendar TextCalendar prmonth8049085
Ref: 26788049085
Ref: library/calendar calendar TextCalendar formatyear8049231
Ref: 26798049231
Ref: library/calendar calendar TextCalendar pryear8049768
Ref: 267a8049768
Ref: library/calendar calendar HTMLCalendar8049923
Ref: b3b8049923
Ref: library/calendar calendar HTMLCalendar formatmonth8050094
Ref: 267b8050094
Ref: library/calendar calendar HTMLCalendar formatyear8050344
Ref: 267c8050344
Ref: library/calendar calendar HTMLCalendar formatyearpage8050525
Ref: 267d8050525
Ref: library/calendar calendar HTMLCalendar formatmonthname8051038
Ref: 267e8051038
Ref: library/calendar calendar HTMLCalendar cssclasses8051412
Ref: 267f8051412
Ref: library/calendar calendar HTMLCalendar cssclass_noday8051826
Ref: 26808051826
Ref: library/calendar calendar HTMLCalendar cssclasses_weekday_head8051987
Ref: 26818051987
Ref: library/calendar calendar HTMLCalendar cssclass_month_head8052202
Ref: 26828052202
Ref: library/calendar calendar HTMLCalendar cssclass_month8052405
Ref: 26838052405
Ref: library/calendar calendar HTMLCalendar cssclass_year8052614
Ref: 26848052614
Ref: library/calendar calendar HTMLCalendar cssclass_year_head8052829
Ref: 26858052829
Ref: library/calendar calendar LocaleTextCalendar8053738
Ref: 7478053738
Ref: library/calendar calendar LocaleHTMLCalendar8053979
Ref: 7488053979
Ref: library/calendar calendar setfirstweekday8054563
Ref: 26618054563
Ref: library/calendar calendar firstweekday8055037
Ref: 268b8055037
Ref: library/calendar calendar isleap8055147
Ref: 268c8055147
Ref: library/calendar calendar leapdays8055275
Ref: 268d8055275
Ref: library/calendar calendar weekday8055500
Ref: 268e8055500
Ref: library/calendar calendar weekheader8055699
Ref: 268f8055699
Ref: library/calendar calendar monthrange8055859
Ref: 26908055859
Ref: library/calendar calendar monthcalendar8056028
Ref: 26918056028
Ref: library/calendar calendar prmonth8056309
Ref: 26928056309
Ref: library/calendar calendar month8056441
Ref: 16a48056441
Ref: library/calendar calendar prcal8056641
Ref: 26938056641
Ref: library/calendar calendar calendar8056785
Ref: 26948056785
Ref: library/calendar calendar timegm8057007
Ref: 26958057007
Ref: library/calendar calendar day_name8057460
Ref: 26968057460
Ref: library/calendar calendar day_abbr8057759
Ref: 26978057759
Ref: library/calendar calendar MONDAY8058038
Ref: 26638058038
Ref: library/calendar calendar TUESDAY8058064
Ref: 26868058064
Ref: library/calendar calendar WEDNESDAY8058091
Ref: 26878058091
Ref: library/calendar calendar THURSDAY8058120
Ref: 26888058120
Ref: library/calendar calendar FRIDAY8058148
Ref: 26898058148
Ref: library/calendar calendar SATURDAY8058174
Ref: 268a8058174
Ref: library/calendar calendar SUNDAY8058202
Ref: 26648058202
Ref: library/calendar calendar Day8058362
Ref: 4858058362
Ref: library/calendar calendar month_name8058609
Ref: 26988058609
Ref: library/calendar calendar month_abbr8059077
Ref: 26998059077
Ref: library/calendar calendar JANUARY8059519
Ref: 2f98059519
Ref: library/calendar calendar FEBRUARY8059546
Ref: 2fa8059546
Ref: library/calendar calendar MARCH8059574
Ref: 269a8059574
Ref: library/calendar calendar APRIL8059599
Ref: 269b8059599
Ref: library/calendar calendar MAY8059624
Ref: 269c8059624
Ref: library/calendar calendar JUNE8059647
Ref: 269d8059647
Ref: library/calendar calendar JULY8059671
Ref: 269e8059671
Ref: library/calendar calendar AUGUST8059695
Ref: 269f8059695
Ref: library/calendar calendar SEPTEMBER8059721
Ref: 26a08059721
Ref: library/calendar calendar OCTOBER8059750
Ref: 26a18059750
Ref: library/calendar calendar NOVEMBER8059777
Ref: 26a28059777
Ref: library/calendar calendar DECEMBER8059805
Ref: 26a38059805
Ref: library/calendar calendar Month8059973
Ref: 4848059973
Ref: library/calendar calendar IllegalMonthError8060287
Ref: 16a38060287
Ref: library/calendar calendar IllegalMonthError month8060463
Ref: 26a48060463
Ref: library/calendar calendar IllegalWeekdayError8060527
Ref: 26a58060527
Ref: library/calendar calendar IllegalWeekdayError weekday8060708
Ref: 26a68060708
Ref: calendar — General calendar-related functions-Footnote-18061070
Node: Command-Line Usage8061138
Ref: library/calendar calendar-cli8061240
Ref: 26a78061240
Ref: library/calendar command-line-usage8061240
Ref: 26a88061240
Ref: library/calendar cmdoption-calendar-help8063979
Ref: 26a98063979
Ref: library/calendar cmdoption-calendar-h8063979
Ref: 26aa8063979
Ref: library/calendar cmdoption-calendar-locale8064041
Ref: 26ab8064041
Ref: library/calendar cmdoption-calendar-L8064041
Ref: 26ac8064041
Ref: library/calendar cmdoption-calendar-encoding8064161
Ref: 26ad8064161
Ref: library/calendar cmdoption-calendar-e8064161
Ref: 26ae8064161
Ref: library/calendar cmdoption-calendar-type8064318
Ref: 26af8064318
Ref: library/calendar cmdoption-calendar-t8064318
Ref: 26b08064318
Ref: library/calendar cmdoption-calendar-first-weekday8064440
Ref: 26b18064440
Ref: library/calendar cmdoption-calendar-f8064440
Ref: 26b28064440
Ref: library/calendar cmdoption-calendar-arg-year8064642
Ref: 26b38064642
Ref: library/calendar cmdoption-calendar-arg-month8064733
Ref: 26b48064733
Ref: library/calendar cmdoption-calendar-width8064985
Ref: 26b58064985
Ref: library/calendar cmdoption-calendar-w8064985
Ref: 26b68064985
Ref: library/calendar cmdoption-calendar-lines8065183
Ref: 26b78065183
Ref: library/calendar cmdoption-calendar-l8065183
Ref: 26b88065183
Ref: library/calendar cmdoption-calendar-spacing8065374
Ref: 26b98065374
Ref: library/calendar cmdoption-calendar-s8065374
Ref: 26ba8065374
Ref: library/calendar cmdoption-calendar-months8065517
Ref: 26bb8065517
Ref: library/calendar cmdoption-calendar-m8065517
Ref: 26bc8065517
Ref: library/calendar cmdoption-calendar-css8065639
Ref: 26bd8065639
Ref: library/calendar cmdoption-calendar-c8065639
Ref: 26be8065639
Node: collections — Container datatypes8065836
Ref: library/collections doc8066039
Ref: 26bf8066039
Ref: library/collections collections-container-datatypes8066039
Ref: 26c08066039
Ref: library/collections module-collections8066039
Ref: 1d8066039
Ref: library/collections translation-repo8066039
Ref: 26c18066039
Ref: collections — Container datatypes-Footnote-18068030
Node: ChainMap objects8068111
Ref: library/collections chainmap-objects8068223
Ref: 26c28068223
Ref: library/collections collections ChainMap8068613
Ref: c3c8068613
Ref: library/collections collections ChainMap maps8069628
Ref: 26c38069628
Ref: library/collections collections ChainMap new_child8069931
Ref: f5a8069931
Ref: library/collections collections ChainMap parents8070739
Ref: 26c48070739
Ref: ChainMap objects-Footnote-18072682
Ref: ChainMap objects-Footnote-28072724
Ref: ChainMap objects-Footnote-38072819
Ref: ChainMap objects-Footnote-48072866
Ref: ChainMap objects-Footnote-58072945
Ref: ChainMap objects-Footnote-68073042
Node: ChainMap Examples and Recipes8073095
Ref: library/collections chainmap-examples-and-recipes8073177
Ref: 26c58073177
Node: Counter objects8076291
Ref: library/collections counter-objects8076425
Ref: 26c68076425
Ref: library/collections collections Counter8077139
Ref: 10d58077139
Ref: library/collections collections Counter elements8079210
Ref: 134d8079210
Ref: library/collections collections Counter most_common8079627
Ref: 134c8079627
Ref: library/collections collections Counter subtract8080083
Ref: 12238080083
Ref: library/collections collections Counter total8080727
Ref: 26c78080727
Ref: library/collections collections Counter fromkeys8081057
Ref: 26c88081057
Ref: library/collections collections Counter update8081170
Ref: 15c88081170
Ref: Counter objects-Footnote-18086367
Ref: Counter objects-Footnote-28086446
Ref: Counter objects-Footnote-38086493
Node: deque objects8086586
Ref: library/collections deque-objects8086723
Ref: 26c98086723
Ref: library/collections collections deque8086776
Ref: 5df8086776
Ref: library/collections collections deque append8088225
Ref: 26ca8088225
Ref: library/collections collections deque appendleft8088314
Ref: 26cb8088314
Ref: library/collections collections deque clear8088406
Ref: 26cc8088406
Ref: library/collections collections deque copy8088505
Ref: e028088505
Ref: library/collections collections deque count8088611
Ref: 12258088611
Ref: library/collections collections deque extend8088743
Ref: 26cd8088743
Ref: library/collections collections deque extendleft8088888
Ref: 26ce8088888
Ref: library/collections collections deque index8089138
Ref: e008089138
Ref: library/collections collections deque insert8089420
Ref: e018089420
Ref: library/collections collections deque pop8089687
Ref: 26cf8089687
Ref: library/collections collections deque popleft8089858
Ref: 26d08089858
Ref: library/collections collections deque remove8090032
Ref: 1a758090032
Ref: library/collections collections deque reverse8090176
Ref: 12268090176
Ref: library/collections collections deque rotate8090330
Ref: 1a368090330
Ref: library/collections collections deque maxlen8090742
Ref: 134e8090742
Node: deque Recipes8093401
Ref: library/collections deque-recipes8093464
Ref: 26d18093464
Ref: deque Recipes-Footnote-18095928
Node: defaultdict objects8095989
Ref: library/collections defaultdict-objects8096167
Ref: 26d28096167
Ref: library/collections collections defaultdict8096232
Ref: 12018096232
Ref: library/collections collections defaultdict __missing__8097176
Ref: 26d48097176
Ref: library/collections collections defaultdict default_factory8098352
Ref: 26d38098352
Ref: defaultdict objects-Footnote-18098774
Node: defaultdict Examples8098816
Ref: library/collections defaultdict-examples8098892
Ref: 26d58098892
Node: namedtuple Factory Function for Tuples with Named Fields8101574
Ref: library/collections namedtuple-factory-function-for-tuples-with-named-fields8101758
Ref: 26d68101758
Ref: library/collections collections namedtuple8102139
Ref: 1ca8102139
Ref: library/collections collections somenamedtuple _make8106178
Ref: 26d88106178
Ref: library/collections collections somenamedtuple _asdict8106412
Ref: 9ec8106412
Ref: library/collections collections somenamedtuple _replace8107092
Ref: 26d98107092
Ref: library/collections collections somenamedtuple _fields8107711
Ref: 26da8107711
Ref: library/collections collections somenamedtuple _field_defaults8108207
Ref: 26d78108207
Node: OrderedDict objects8110976
Ref: library/collections ordereddict-objects8111157
Ref: 26db8111157
Ref: library/collections collections OrderedDict8113579
Ref: 5de8113579
Ref: library/collections collections OrderedDict popitem8113897
Ref: 13368113897
Ref: library/collections collections OrderedDict move_to_end8114171
Ref: 12248114171
Ref: library/collections collections-ordereddict-eq8114890
Ref: 16cf8114890
Ref: OrderedDict objects-Footnote-18115814
Ref: OrderedDict objects-Footnote-28115856
Node: OrderedDict Examples and Recipes8115898
Ref: library/collections ordereddict-examples-and-recipes8115986
Ref: 26dd8115986
Node: UserDict objects8119027
Ref: library/collections userdict-objects8119168
Ref: 26de8119168
Ref: library/collections collections UserDict8119534
Ref: 1b268119534
Ref: library/collections collections UserDict data8120128
Ref: 26df8120128
Node: UserList objects8120249
Ref: library/collections userlist-objects8120389
Ref: 26e08120389
Ref: library/collections collections UserList8120904
Ref: 15338120904
Ref: library/collections collections UserList data8121483
Ref: 26e18121483
Node: UserString objects8122270
Ref: library/collections userstring-objects8122385
Ref: 26e28122385
Ref: library/collections collections UserString8122747
Ref: e038122747
Ref: library/collections collections UserString data8123329
Ref: 26e38123329
Node: collections abc — Abstract Base Classes for Containers8123623
Ref: library/collections abc doc8123809
Ref: 26e48123809
Ref: library/collections abc collections-abc-abstract-base-classes-for-containers8123809
Ref: 26e58123809
Ref: library/collections abc module-collections abc8123809
Ref: 1e8123809
Ref: library/collections abc translation-repo8123809
Ref: 26e68123809
Ref: collections abc — Abstract Base Classes for Containers-Footnote-18127825
Ref: collections abc — Abstract Base Classes for Containers-Footnote-28127902
Node: Collections Abstract Base Classes8127944
Ref: library/collections abc collections-abstract-base-classes8128138
Ref: 87f8128138
Ref: library/collections abc id18128138
Ref: 26e78128138
Ref: Collections Abstract Base Classes-Footnote-18137845
Ref: Collections Abstract Base Classes-Footnote-28138134
Ref: Collections Abstract Base Classes-Footnote-38138423
Ref: Collections Abstract Base Classes-Footnote-48138712
Ref: Collections Abstract Base Classes-Footnote-58139064
Ref: Collections Abstract Base Classes-Footnote-68139353
Ref: Collections Abstract Base Classes-Footnote-78139642
Ref: Collections Abstract Base Classes-Footnote-88139931
Ref: Collections Abstract Base Classes-Footnote-98140220
Ref: Collections Abstract Base Classes-Footnote-108140509
Ref: Collections Abstract Base Classes-Footnote-118140799
Ref: Collections Abstract Base Classes-Footnote-128141089
Ref: Collections Abstract Base Classes-Footnote-138141379
Ref: Collections Abstract Base Classes-Footnote-148141669
Ref: Collections Abstract Base Classes-Footnote-158141959
Ref: Collections Abstract Base Classes-Footnote-168142249
Node: Collections Abstract Base Classes – Detailed Descriptions8142539
Ref: library/collections abc collections-abstract-base-classes-detailed-descriptions8142762
Ref: 26e98142762
Ref: library/collections abc collections abc Container8142897
Ref: 24078142897
Ref: library/collections abc collections abc Hashable8143015
Ref: 4f88143015
Ref: library/collections abc collections abc Sized8143122
Ref: 4f98143122
Ref: library/collections abc collections abc Callable8143226
Ref: 7ef8143226
Ref: library/collections abc collections abc Iterable8143451
Ref: 24058143451
Ref: library/collections abc collections abc Collection8143922
Ref: cab8143922
Ref: library/collections abc collections abc Iterator8144037
Ref: 24068144037
Ref: library/collections abc collections abc Reversible8144233
Ref: cac8144233
Ref: library/collections abc collections abc Generator8144393
Ref: e0b8144393
Ref: library/collections abc collections abc Sequence8144810
Ref: 12098144810
Ref: library/collections abc collections abc MutableSequence8144846
Ref: 1a18144846
Ref: library/collections abc collections abc ByteString8144889
Ref: 2e78144889
Ref: library/collections abc collections abc ByteString index8145524
Ref: 26eb8145524
Ref: library/collections abc collections abc Set8146916
Ref: 23fd8146916
Ref: library/collections abc collections abc MutableSet8146947
Ref: 24088146947
Ref: library/collections abc collections abc Mapping8147041
Ref: 8d38147041
Ref: library/collections abc collections abc MutableMapping8147076
Ref: 10f08147076
Ref: library/collections abc collections abc MappingView8147178
Ref: 24098147178
Ref: library/collections abc collections abc ItemsView8147217
Ref: 240b8147217
Ref: library/collections abc collections abc KeysView8147254
Ref: 240a8147254
Ref: library/collections abc collections abc ValuesView8147290
Ref: 240c8147290
Ref: library/collections abc collections abc Awaitable8147396
Ref: e0c8147396
Ref: library/collections abc collections abc Coroutine8148152
Ref: e0d8148152
Ref: library/collections abc collections abc AsyncIterable8149195
Ref: e0f8149195
Ref: library/collections abc collections abc AsyncIterator8149394
Ref: e0e8149394
Ref: library/collections abc collections abc AsyncGenerator8149610
Ref: cae8149610
Ref: library/collections abc collections abc Buffer8149938
Ref: 2e98149938
Ref: Collections Abstract Base Classes – Detailed Descriptions-Footnote-18150177
Ref: Collections Abstract Base Classes – Detailed Descriptions-Footnote-28150219
Ref: Collections Abstract Base Classes – Detailed Descriptions-Footnote-38150277
Ref: Collections Abstract Base Classes – Detailed Descriptions-Footnote-48150319
Ref: Collections Abstract Base Classes – Detailed Descriptions-Footnote-58150361
Node: Examples and Recipes8150403
Ref: library/collections abc examples-and-recipes8150584
Ref: 26ec8150584
Ref: Examples and Recipes-Footnote-18153555
Ref: Examples and Recipes-Footnote-28153608
Node: heapq — Heap queue algorithm8153650
Ref: library/heapq doc8153837
Ref: 26ed8153837
Ref: library/heapq heapq-heap-queue-algorithm8153837
Ref: 26ee8153837
Ref: library/heapq module-heapq8153837
Ref: 698153837
Ref: library/heapq translation-repo8153837
Ref: 26ef8153837
Ref: library/heapq heapq heapify8155443
Ref: 26f08155443
Ref: library/heapq heapq heappush8155540
Ref: 150b8155540
Ref: library/heapq heapq heappop8155665
Ref: 150c8155665
Ref: library/heapq heapq heappushpop8155930
Ref: 26f18155930
Ref: library/heapq heapq heapreplace8156203
Ref: 26f28156203
Ref: library/heapq heapq merge8157051
Ref: e368157051
Ref: library/heapq heapq nlargest8158214
Ref: 26f38158214
Ref: library/heapq heapq nsmallest8158612
Ref: 26f48158612
Ref: heapq — Heap queue algorithm-Footnote-18159481
Node: Basic Examples8159546
Ref: library/heapq basic-examples8159671
Ref: 26f58159671
Ref: Basic Examples-Footnote-18160638
Node: Priority Queue Implementation Notes8160685
Ref: library/heapq priority-queue-implementation-notes8160825
Ref: 26f68160825
Ref: Priority Queue Implementation Notes-Footnote-18163761
Node: Theory8163814
Ref: library/heapq theory8163931
Ref: 26f78163931
Ref: Theory-Footnote-18168097
Node: bisect — Array bisection algorithm8168753
Ref: library/bisect doc8168928
Ref: 26f88168928
Ref: library/bisect bisect-array-bisection-algorithm8168928
Ref: 26f98168928
Ref: library/bisect module-bisect8168928
Ref: 118168928
Ref: library/bisect translation-repo8168928
Ref: 26fa8168928
Ref: library/bisect bisect-functions8170340
Ref: 26fc8170340
Ref: library/bisect bisect bisect_left8170379
Ref: 26fd8170379
Ref: library/bisect bisect bisect_right8171574
Ref: 26fe8171574
Ref: library/bisect bisect bisect8171645
Ref: 26ff8171645
Ref: library/bisect bisect insort_left8172179
Ref: 26fb8172179
Ref: library/bisect bisect insort_right8172831
Ref: 27008172831
Ref: library/bisect bisect insort8172902
Ref: 27018172902
Ref: bisect — Array bisection algorithm-Footnote-18173738
Node: Performance Notes8173804
Ref: library/bisect performance-notes8173925
Ref: 27028173925
Ref: Performance Notes-Footnote-18175302
Ref: Performance Notes-Footnote-28175357
Node: Searching Sorted Lists8175427
Ref: library/bisect searching-sorted-lists8175568
Ref: 27038175568
Node: Examples<3>8176790
Ref: library/bisect examples8176905
Ref: 27048176905
Ref: library/bisect bisect-example8176940
Ref: 27058176940
Node: array — Efficient arrays of numeric values8179419
Ref: library/array doc8179591
Ref: 27068179591
Ref: library/array array-efficient-arrays-of-numeric-values8179591
Ref: 27078179591
Ref: library/array module-array8179591
Ref: 78179591
Ref: library/array translation-repo8179591
Ref: 27088179591
Ref: library/array array typecodes8184549
Ref: 270a8184549
Ref: library/array array array8184662
Ref: 1a08184662
Ref: library/array array array typecode8185941
Ref: 270d8185941
Ref: library/array array array itemsize8186031
Ref: 27098186031
Ref: library/array array array append8186152
Ref: 270e8186152
Ref: library/array array array buffer_info8186277
Ref: 270f8186277
Ref: library/array array array byteswap8187394
Ref: 27108187394
Ref: library/array array array count8187745
Ref: 27118187745
Ref: library/array array array extend8187849
Ref: 270c8187849
Ref: library/array array array frombytes8188236
Ref: 12b88188236
Ref: library/array array array fromfile8188611
Ref: 13088188611
Ref: library/array array array fromlist8188954
Ref: 27128188954
Ref: library/array array array fromunicode8189168
Ref: 270b8189168
Ref: library/array array array index8189528
Ref: 7e58189528
Ref: library/array array array insert8189991
Ref: 27138189991
Ref: library/array array array pop8190201
Ref: 27148190201
Ref: library/array array array remove8190438
Ref: 27158190438
Ref: library/array array array clear8190540
Ref: 1a28190540
Ref: library/array array array reverse8190648
Ref: 27168190648
Ref: library/array array array tobytes8190733
Ref: 12b78190733
Ref: library/array array array tofile8191078
Ref: 13098191078
Ref: library/array array array tolist8191204
Ref: 27178191204
Ref: library/array array array tounicode8191302
Ref: 27188191302
Ref: array — Efficient arrays of numeric values-Footnote-18192550
Node: weakref — Weak references8192577
Ref: library/weakref doc8192773
Ref: 27198192773
Ref: library/weakref mod-weakref8192773
Ref: f418192773
Ref: library/weakref module-weakref8192773
Ref: 1148192773
Ref: library/weakref translation-repo8192773
Ref: 271a8192773
Ref: library/weakref weakref-weak-references8192773
Ref: 271b8192773
Ref: library/weakref weakref ref8196806
Ref: 102b8196806
Ref: library/weakref weakref ref __callback__8198611
Ref: 102c8198611
Ref: library/weakref weakref proxy8198977
Ref: a5f8198977
Ref: library/weakref weakref getweakrefcount8199973
Ref: 271d8199973
Ref: library/weakref weakref getweakrefs8200106
Ref: 271e8200106
Ref: library/weakref weakref WeakKeyDictionary8200240
Ref: 1b008200240
Ref: library/weakref weakref WeakKeyDictionary keyrefs8202089
Ref: 271f8202089
Ref: library/weakref weakref WeakValueDictionary8202192
Ref: 1aff8202192
Ref: library/weakref weakref WeakValueDictionary valuerefs8202664
Ref: 27208202664
Ref: library/weakref weakref WeakSet8202773
Ref: 5e08202773
Ref: library/weakref weakref WeakMethod8202957
Ref: 102a8202957
Ref: library/weakref weakref finalize8204005
Ref: a8b8204005
Ref: library/weakref weakref finalize __call__8205308
Ref: 27218205308
Ref: library/weakref weakref finalize detach8205519
Ref: 27228205519
Ref: library/weakref weakref finalize peek8205720
Ref: 27238205720
Ref: library/weakref weakref finalize alive8205889
Ref: 27248205889
Ref: library/weakref weakref finalize atexit8206004
Ref: 27258206004
Ref: library/weakref weakref ReferenceType8206605
Ref: 19038206605
Ref: library/weakref weakref ProxyType8206689
Ref: 19048206689
Ref: library/weakref weakref CallableProxyType8206787
Ref: 19058206787
Ref: library/weakref weakref ProxyTypes8206879
Ref: 27268206879
Ref: weakref — Weak references-Footnote-18207509
Ref: weakref — Weak references-Footnote-28207576
Ref: weakref — Weak references-Footnote-38207618
Ref: weakref — Weak references-Footnote-48207660
Node: Weak Reference Objects8207702
Ref: library/weakref weak-reference-objects8207807
Ref: 27278207807
Ref: library/weakref weakref-objects8207807
Ref: 27288207807
Node: Example<2>8210334
Ref: library/weakref example8210465
Ref: 27298210465
Ref: library/weakref weakref-example8210465
Ref: 272a8210465
Node: Finalizer Objects8211006
Ref: library/weakref finalize-examples8211156
Ref: 272b8211156
Ref: library/weakref finalizer-objects8211156
Ref: 272c8211156
Node: Comparing finalizers with __del__ methods8213007
Ref: library/weakref comparing-finalizers-with-del-methods8213138
Ref: 272d8213138
Node: types — Dynamic type creation and names for built-in types8215965
Ref: library/types doc8216158
Ref: 272e8216158
Ref: library/types module-types8216158
Ref: 1038216158
Ref: library/types translation-repo8216158
Ref: 272f8216158
Ref: library/types types-dynamic-type-creation-and-names-for-built-in-types8216158
Ref: 27308216158
Ref: types — Dynamic type creation and names for built-in types-Footnote-18216961
Node: Dynamic Type Creation8217026
Ref: library/types dynamic-type-creation8217179
Ref: 27318217179
Ref: library/types types new_class8217242
Ref: 11a58217242
Ref: library/types types prepare_class8217958
Ref: 11a68217958
Ref: library/types types resolve_bases8219129
Ref: bba8219129
Ref: library/types types get_original_bases8219689
Ref: 4d18219689
Ref: Dynamic Type Creation-Footnote-18221250
Ref: Dynamic Type Creation-Footnote-28221292
Ref: Dynamic Type Creation-Footnote-38221334
Ref: Dynamic Type Creation-Footnote-48221376
Node: Standard Interpreter Types8221418
Ref: library/types standard-interpreter-types8221620
Ref: 27328221620
Ref: library/types types NoneType8222176
Ref: 8588222176
Ref: library/types types FunctionType8222266
Ref: 88a8222266
Ref: library/types types LambdaType8222295
Ref: 27338222295
Ref: library/types types GeneratorType8222652
Ref: 173e8222652
Ref: library/types types CoroutineType8222779
Ref: ebd8222779
Ref: library/types types AsyncGeneratorType8222936
Ref: 27348222936
Ref: library/types types CodeType8223122
Ref: 2df8223122
Ref: library/types types CellType8223716
Ref: 27358223716
Ref: library/types types MethodType8223894
Ref: 19298223894
Ref: library/types types BuiltinFunctionType8223981
Ref: 27368223981
Ref: library/types types BuiltinMethodType8224017
Ref: 27378224017
Ref: library/types types WrapperDescriptorType8224241
Ref: bb78224241
Ref: library/types types MethodWrapperType8224459
Ref: 64e8224459
Ref: library/types types NotImplementedType8224662
Ref: 8598224662
Ref: library/types types MethodDescriptorType8224772
Ref: bb88224772
Ref: library/types types ClassMethodDescriptorType8224929
Ref: bb98224929
Ref: library/types types ModuleType8225116
Ref: e458225116
Ref: library/types types EllipsisType8225896
Ref: 8578225896
Ref: library/types types GenericAlias8225995
Ref: 7f08225995
Ref: library/types types UnionType8226909
Ref: 63d8226909
Ref: library/types types TracebackType8227019
Ref: b0b8227019
Ref: library/types types FrameType8227347
Ref: 19928227347
Ref: library/types types GetSetDescriptorType8227500
Ref: 27388227500
Ref: library/types types MemberDescriptorType8227867
Ref: 27398227867
Ref: library/types types MappingProxyType8228659
Ref: 4708228659
Ref: library/types types MappingProxyType copy8229653
Ref: 273a8229653
Ref: library/types types MappingProxyType get8229739
Ref: 273b8229739
Ref: library/types types MappingProxyType items8230012
Ref: 273c8230012
Ref: library/types types MappingProxyType keys8230142
Ref: 273d8230142
Ref: library/types types MappingProxyType values8230233
Ref: 273e8230233
Ref: library/types types CapsuleType8230603
Ref: 273f8230603
Ref: Standard Interpreter Types-Footnote-18230745
Ref: Standard Interpreter Types-Footnote-28230787
Node: Additional Utility Classes and Functions8230829
Ref: library/types additional-utility-classes-and-functions8231037
Ref: 27418231037
Ref: library/types types SimpleNamespace8231138
Ref: 1d18231138
Ref: library/types types DynamicClassAttribute8233152
Ref: 62d8233152
Node: Coroutine Utility Functions8233828
Ref: library/types coroutine-utility-functions8234001
Ref: 27428234001
Ref: library/types types coroutine8234076
Ref: ebc8234076
Node: copy — Shallow and deep copy operations8234903
Ref: library/copy doc8235099
Ref: 27438235099
Ref: library/copy copy-shallow-and-deep-copy-operations8235099
Ref: 27448235099
Ref: library/copy module-copy8235099
Ref: 258235099
Ref: library/copy translation-repo8235099
Ref: 27458235099
Ref: library/copy copy copy8235654
Ref: 5378235654
Ref: library/copy copy deepcopy8235723
Ref: b8a8235723
Ref: library/copy copy replace8235801
Ref: 1518235801
Ref: library/copy copy Error8235982
Ref: 27468235982
Ref: library/copy shallow-vs-deep-copy8236049
Ref: 1d978236049
Ref: library/copy object __copy__8238084
Ref: 161d8238084
Ref: library/copy object __deepcopy__8238215
Ref: 161e8238215
Ref: library/copy object __replace__8238919
Ref: 1528238919
Ref: copy — Shallow and deep copy operations-Footnote-18239296
Node: pprint — Data pretty printer8239360
Ref: library/pprint doc8239537
Ref: 27478239537
Ref: library/pprint module-pprint8239537
Ref: ae8239537
Ref: library/pprint pprint-data-pretty-printer8239537
Ref: 27488239537
Ref: library/pprint translation-repo8239537
Ref: 27498239537
Ref: pprint — Data pretty printer-Footnote-18240692
Node: Functions<4>8240758
Ref: library/pprint functions8240867
Ref: 274a8240867
Ref: library/pprint pprint-functions8240867
Ref: 274b8240867
Ref: library/pprint pprint pp8240906
Ref: a308240906
Ref: library/pprint pprint pprint8243500
Ref: 82e8243500
Ref: library/pprint pprint pformat8243889
Ref: fb98243889
Ref: library/pprint pprint isreadable8244340
Ref: 274c8244340
Ref: library/pprint pprint isrecursive8244648
Ref: 274d8244648
Ref: library/pprint pprint saferepr8244949
Ref: 274e8244949
Node: PrettyPrinter Objects8245597
Ref: library/pprint id18245725
Ref: 274f8245725
Ref: library/pprint prettyprinter-objects8245725
Ref: 27508245725
Ref: library/pprint pprint PrettyPrinter8245788
Ref: fb88245788
Ref: library/pprint pprint PrettyPrinter pformat8247451
Ref: 27518247451
Ref: library/pprint pprint PrettyPrinter pprint8247650
Ref: 27528247650
Ref: library/pprint pprint PrettyPrinter isreadable8248037
Ref: 27538248037
Ref: library/pprint pprint PrettyPrinter isrecursive8248439
Ref: 27548248439
Ref: library/pprint pprint PrettyPrinter format8248755
Ref: 1a8e8248755
Node: Example<3>8249908
Ref: library/pprint example8250015
Ref: 27558250015
Ref: library/pprint pprint-example8250015
Ref: 27568250015
Ref: Example<3>-Footnote-18257313
Node: reprlib — Alternate repr implementation8257338
Ref: library/reprlib doc8257507
Ref: 27578257507
Ref: library/reprlib module-reprlib8257507
Ref: bb8257507
Ref: library/reprlib reprlib-alternate-repr-implementation8257507
Ref: 27588257507
Ref: library/reprlib translation-repo8257507
Ref: 27598257507
Ref: library/reprlib reprlib Repr8257998
Ref: 275a8257998
Ref: library/reprlib reprlib aRepr8258978
Ref: 275c8258978
Ref: library/reprlib reprlib repr8259254
Ref: 275d8259254
Ref: library/reprlib reprlib recursive_repr8259656
Ref: 12388259656
Ref: reprlib — Alternate repr implementation-Footnote-18260454
Node: Repr Objects8260521
Ref: library/reprlib id18260644
Ref: 275b8260644
Ref: library/reprlib repr-objects8260644
Ref: 275f8260644
Ref: library/reprlib reprlib Repr fillvalue8260885
Ref: 27608260885
Ref: library/reprlib reprlib Repr maxlevel8261034
Ref: 27618261034
Ref: library/reprlib reprlib Repr maxdict8261158
Ref: 27628261158
Ref: library/reprlib reprlib Repr maxlist8261186
Ref: 27638261186
Ref: library/reprlib reprlib Repr maxtuple8261214
Ref: 27648261214
Ref: library/reprlib reprlib Repr maxset8261243
Ref: 27658261243
Ref: library/reprlib reprlib Repr maxfrozenset8261270
Ref: 27668261270
Ref: library/reprlib reprlib Repr maxdeque8261303
Ref: 27678261303
Ref: library/reprlib reprlib Repr maxarray8261332
Ref: 27688261332
Ref: library/reprlib reprlib Repr maxlong8261560
Ref: 27698261560
Ref: library/reprlib reprlib Repr maxstring8261729
Ref: 276a8261729
Ref: library/reprlib reprlib Repr maxother8262086
Ref: 276b8262086
Ref: library/reprlib reprlib Repr indent8262365
Ref: 276c8262365
Ref: library/reprlib reprlib Repr repr8263846
Ref: 275e8263846
Ref: library/reprlib reprlib Repr repr18263986
Ref: 276d8263986
Node: Subclassing Repr Objects8264797
Ref: library/reprlib subclassing-repr-objects8264920
Ref: 276e8264920
Ref: library/reprlib subclassing-reprs8264920
Ref: 276f8264920
Node: enum — Support for enumerations8265617
Ref: library/enum doc8265820
Ref: 27708265820
Ref: library/enum enum-support-for-enumerations8265820
Ref: 27718265820
Ref: library/enum module-enum8265820
Ref: 568265820
Ref: library/enum translation-repo8265820
Ref: 27728265820
Ref: enum — Support for enumerations-Footnote-18267681
Node: Module contents8267745
Ref: library/enum module-contents8267849
Ref: 27778267849
Node: Data types8271575
Ref: library/enum data-types8271712
Ref: 277b8271712
Ref: library/enum enum EnumType8271753
Ref: 1e58271753
Ref: library/enum enum EnumType __call__8272376
Ref: 277d8272376
Ref: library/enum enum EnumType __contains__8273593
Ref: 277e8273593
Ref: library/enum enum EnumType __dir__8274013
Ref: 277f8274013
Ref: library/enum enum EnumType __getitem__8274400
Ref: 27808274400
Ref: library/enum enum EnumType __iter__8274612
Ref: 27818274612
Ref: library/enum enum EnumType __len__8274805
Ref: 27828274805
Ref: library/enum enum EnumType __members__8274935
Ref: 27838274935
Ref: library/enum enum EnumType __reversed__8275059
Ref: 27848275059
Ref: library/enum enum Enum8275274
Ref: 6338275274
Ref: library/enum enum Enum name8275356
Ref: 27858275356
Ref: library/enum enum Enum value8275498
Ref: 27868275498
Ref: library/enum enum Enum _name_8276358
Ref: 27888276358
Ref: library/enum enum Enum _value_8276417
Ref: 27898276417
Ref: library/enum enum Enum _order_8276515
Ref: 278a8276515
Ref: library/enum enum Enum _ignore_8277525
Ref: 278b8277525
Ref: library/enum enum Enum __dir__8277925
Ref: 19a88277925
Ref: library/enum enum Enum _generate_next_value_8278794
Ref: 278d8278794
Ref: library/enum enum Enum __init__8280176
Ref: 278e8280176
Ref: library/enum enum Enum __init_subclass__8280628
Ref: 278f8280628
Ref: library/enum enum Enum _missing_8280799
Ref: 27908280799
Ref: library/enum enum Enum __new__8281699
Ref: 27878281699
Ref: library/enum enum Enum __repr__8282365
Ref: 189d8282365
Ref: library/enum enum Enum __str__8283141
Ref: 6258283141
Ref: library/enum enum Enum __format__8283816
Ref: 6238283816
Ref: library/enum enum Enum _add_alias_8284732
Ref: 27918284732
Ref: library/enum enum Enum _add_value_alias_8285080
Ref: 27928285080
Ref: library/enum enum IntEnum8285494
Ref: d068285494
Ref: library/enum enum StrEnum8286530
Ref: 61d8286530
Ref: library/enum enum Flag8287922
Ref: 6268287922
Ref: library/enum enum Flag __contains__8288205
Ref: 27948288205
Ref: library/enum enum Flag __or__8289644
Ref: 27958289644
Ref: library/enum enum Flag __and__8289822
Ref: 27968289822
Ref: library/enum enum Flag __xor__8290058
Ref: 27978290058
Ref: library/enum enum Flag _numeric_repr_8290594
Ref: 27988290594
Ref: library/enum enum IntFlag8291089
Ref: cc18291089
Ref: library/enum enum ReprEnum8292706
Ref: 61e8292706
Ref: library/enum enum EnumCheck8293220
Ref: 6298293220
Ref: library/enum enum EnumCheck UNIQUE8293424
Ref: 27998293424
Ref: library/enum enum EnumCheck CONTINUOUS8293911
Ref: 279a8293911
Ref: library/enum enum EnumCheck NAMED_FLAGS8294441
Ref: 279b8294441
Ref: library/enum enum FlagBoundary8295312
Ref: 6278295312
Ref: library/enum enum FlagBoundary STRICT8295457
Ref: 279c8295457
Ref: library/enum enum FlagBoundary CONFORM8296106
Ref: 279d8296106
Ref: library/enum enum FlagBoundary EJECT8296575
Ref: 279e8296575
Ref: library/enum enum FlagBoundary KEEP8297015
Ref: 279f8297015
Ref: library/enum enum EnumDict8297541
Ref: 1e48297541
Ref: library/enum enum EnumDict member_names8298263
Ref: 27a08298263
Node: Supported __dunder__ names8298499
Ref: library/enum enum-dunder-sunder8298605
Ref: 27a18298605
Ref: library/enum supported-dunder-names8298605
Ref: 27a28298605
Node: Supported _sunder_ names8299041
Ref: library/enum supported-sunder-names8299147
Ref: 27a38299147
Ref: Supported _sunder_ names-Footnote-18300683
Node: Utilities and decorators8300770
Ref: library/enum ipython-s-rich-display8300897
Ref: 27a48300897
Ref: library/enum utilities-and-decorators8300897
Ref: 27a58300897
Ref: library/enum enum auto8300966
Ref: cc28300966
Ref: library/enum enum property8302494
Ref: 62c8302494
Ref: library/enum enum unique8303015
Ref: 27798303015
Ref: library/enum enum verify8303645
Ref: 6288303645
Ref: library/enum enum member8303901
Ref: 62a8303901
Ref: library/enum enum nonmember8304027
Ref: 62b8304027
Ref: library/enum enum global_enum8304160
Ref: 62e8304160
Ref: library/enum enum show_flag_values8304529
Ref: 277a8304529
Ref: library/enum enum bin8304686
Ref: 15d88304686
Node: Notes8305168
Ref: library/enum notes8305276
Ref: 27788305276
Node: graphlib — Functionality to operate with graph-like structures8306210
Ref: library/graphlib doc8306363
Ref: 27a68306363
Ref: library/graphlib graphlib-functionality-to-operate-with-graph-like-structures8306363
Ref: 27a78306363
Ref: library/graphlib module-graphlib8306363
Ref: 658306363
Ref: library/graphlib translation-repo8306363
Ref: 27a88306363
Ref: library/graphlib graphlib TopologicalSorter8306617
Ref: 8ea8306617
Ref: library/graphlib graphlib TopologicalSorter add8309903
Ref: 27a98309903
Ref: library/graphlib graphlib TopologicalSorter prepare8310680
Ref: 27aa8310680
Ref: library/graphlib graphlib TopologicalSorter is_active8311153
Ref: 27ab8311153
Ref: library/graphlib graphlib TopologicalSorter done8312030
Ref: 27ad8312030
Ref: library/graphlib graphlib TopologicalSorter get_ready8312710
Ref: 27ac8312710
Ref: library/graphlib graphlib TopologicalSorter static_order8313266
Ref: 27ae8313266
Ref: graphlib — Functionality to operate with graph-like structures-Footnote-18314808
Node: Exceptions<4>8314876
Ref: library/graphlib exceptions8314990
Ref: 27b08314990
Ref: library/graphlib graphlib CycleError8315099
Ref: 27af8315099
Node: Numeric and Mathematical Modules8315772
Ref: library/numeric doc8315926
Ref: 27b18315926
Ref: library/numeric numeric8315926
Ref: 27b28315926
Ref: library/numeric numeric-and-mathematical-modules8315926
Ref: 27b38315926
Ref: library/numeric translation-repo8315926
Ref: 27b48315926
Node: numbers — Numeric abstract base classes8316831
Ref: library/numbers doc8316981
Ref: 27b58316981
Ref: library/numbers module-numbers8316981
Ref: 9e8316981
Ref: library/numbers numbers-numeric-abstract-base-classes8316981
Ref: 27b68316981
Ref: library/numbers numbers Number8317411
Ref: 27b78317411
Ref: numbers — Numeric abstract base classes-Footnote-18317707
Ref: numbers — Numeric abstract base classes-Footnote-28317774
Node: The numeric tower8317816
Ref: library/numbers the-numeric-tower8317947
Ref: 27b88317947
Ref: library/numbers numbers Complex8318000
Ref: 27b98318000
Ref: library/numbers numbers Complex real8318445
Ref: 27ba8318445
Ref: library/numbers numbers Complex imag8318538
Ref: 27bb8318538
Ref: library/numbers numbers Complex conjugate8318636
Ref: 27bc8318636
Ref: library/numbers numbers Real8318795
Ref: 234e8318795
Ref: library/numbers numbers Rational8319299
Ref: 13068319299
Ref: library/numbers numbers Rational numerator8319683
Ref: 27bd8319683
Ref: library/numbers numbers Rational denominator8319775
Ref: 27be8319775
Ref: library/numbers numbers Integral8319871
Ref: 216f8319871
Node: Notes for type implementers8320234
Ref: library/numbers notes-for-type-implementers8320365
Ref: 27bf8320365
Node: Adding More Numeric ABCs8321215
Ref: library/numbers adding-more-numeric-abcs8321350
Ref: 27c08321350
Node: Implementing the arithmetic operations8321696
Ref: library/numbers id18321831
Ref: 27c18321831
Ref: library/numbers implementing-the-arithmetic-operations8321831
Ref: 20978321831
Node: math — Mathematical functions8326497
Ref: library/math doc8326708
Ref: 27c28326708
Ref: library/math math-mathematical-functions8326708
Ref: 27c38326708
Ref: library/math module-math8326708
Ref: 8e8326708
Ref: library/math translation-repo8326708
Ref: 27c48326708
Ref: math — Mathematical functions-Footnote-18341348
Ref: math — Mathematical functions-Footnote-28341401
Ref: math — Mathematical functions-Footnote-38341454
Ref: math — Mathematical functions-Footnote-48341507
Node: Number-theoretic functions8341560
Ref: library/math number-theoretic-functions8341688
Ref: 27d68341688
Ref: library/math math comb8341759
Ref: 6d38341759
Ref: library/math math factorial8342350
Ref: 9518342350
Ref: library/math math gcd8342544
Ref: 9198342544
Ref: library/math math isqrt8343079
Ref: a108343079
Ref: library/math math lcm8343599
Ref: 91a8343599
Ref: library/math math perm8344001
Ref: 6d48344001
Node: Floating point arithmetic8344550
Ref: library/math floating-point-arithmetic8344724
Ref: 27d78344724
Ref: library/math math ceil8344793
Ref: 140b8344793
Ref: library/math math fabs8345034
Ref: 27c58345034
Ref: library/math math floor8345103
Ref: 140a8345103
Ref: library/math math fma8345335
Ref: 2058345335
Ref: library/math math fmod8346019
Ref: 22208346019
Ref: library/math math modf8347056
Ref: 27c68347056
Ref: library/math math remainder8347472
Ref: b6e8347472
Ref: library/math math trunc8348500
Ref: 140c8348500
Node: Floating point manipulation functions8349268
Ref: library/math floating-point-manipulation-functions8349459
Ref: 27d88349459
Ref: library/math math copysign8349552
Ref: 14218349552
Ref: library/math math frexp8349766
Ref: 27c78349766
Ref: library/math math isclose8350408
Ref: dde8350408
Ref: library/math math isfinite8352014
Ref: 12308352014
Ref: library/math math isinf8352219
Ref: 141f8352219
Ref: library/math math isnan8352348
Ref: 14208352348
Ref: library/math math ldexp8352466
Ref: 164a8352466
Ref: library/math math nextafter8352601
Ref: 49b8352601
Ref: library/math math ulp8353269
Ref: 91b8353269
Ref: Floating point manipulation functions-Footnote-18354345
Node: Power exponential and logarithmic functions8354387
Ref: library/math power-exponential-and-logarithmic-functions8354584
Ref: 27d98354584
Ref: library/math math cbrt8354691
Ref: 6648354691
Ref: library/math math exp8354784
Ref: 135d8354784
Ref: library/math math exp28355002
Ref: 6638355002
Ref: library/math math expm18355102
Ref: 12318355102
Ref: library/math math log8355711
Ref: 150f8355711
Ref: library/math math log1p8355946
Ref: 14268355946
Ref: library/math math log28356109
Ref: 111f8356109
Ref: library/math math log108356451
Ref: 27c88356451
Ref: library/math math pow8356583
Ref: 6658356583
Ref: library/math math sqrt8357439
Ref: a118357439
Ref: Power exponential and logarithmic functions-Footnote-18357541
Node: Summation and product functions8357600
Ref: library/math summation-and-product-functions8357778
Ref: 27da8357778
Ref: library/math math dist8357859
Ref: a0d8357859
Ref: library/math math fsum8358190
Ref: 14228358190
Ref: library/math math hypot8358864
Ref: a0e8358864
Ref: library/math math prod8359620
Ref: a0f8359620
Ref: library/math math sumprod8359998
Ref: 49a8359998
Ref: Summation and product functions-Footnote-18360485
Node: Angular conversion8360590
Ref: library/math angular-conversion8360748
Ref: 27db8360748
Ref: library/math math degrees8360803
Ref: 27c98360803
Ref: library/math math radians8360884
Ref: 27ca8360884
Node: Trigonometric functions8360965
Ref: library/math trigonometric-functions8361112
Ref: 27dc8361112
Ref: library/math math acos8361177
Ref: 27cb8361177
Ref: library/math math asin8361304
Ref: 27cc8361304
Ref: library/math math atan8361435
Ref: 27cd8361435
Ref: library/math math atan28361569
Ref: 27ce8361569
Ref: library/math math cos8362069
Ref: 150e8362069
Ref: library/math math sin8362137
Ref: 150d8362137
Ref: library/math math tan8362203
Ref: 27cf8362203
Node: Hyperbolic functions8362272
Ref: library/math hyperbolic-functions8362418
Ref: 27dd8362418
Ref: library/math math acosh8362590
Ref: 14238362590
Ref: library/math math asinh8362671
Ref: 14248362671
Ref: library/math math atanh8362750
Ref: 14258362750
Ref: library/math math cosh8362832
Ref: 27d08362832
Ref: library/math math sinh8362904
Ref: 27d18362904
Ref: library/math math tanh8362974
Ref: 27d28362974
Ref: Hyperbolic functions-Footnote-18363083
Node: Special functions8363142
Ref: library/math special-functions8363277
Ref: 27de8363277
Ref: library/math math erf8363330
Ref: bf98363330
Ref: library/math math erfc8363741
Ref: bfa8363741
Ref: library/math math gamma8364042
Ref: 12328364042
Ref: library/math math lgamma8364143
Ref: 12338364143
Ref: Special functions-Footnote-18364330
Ref: Special functions-Footnote-28364383
Ref: Special functions-Footnote-38364454
Ref: Special functions-Footnote-48364507
Ref: Special functions-Footnote-58364566
Node: Constants<2>8364619
Ref: library/math constants8364725
Ref: 27df8364725
Ref: library/math math pi8364764
Ref: 27d38364764
Ref: library/math math e8364859
Ref: 27d48364859
Ref: library/math math tau8364952
Ref: 27d58364952
Ref: library/math math inf8365332
Ref: ca78365332
Ref: library/math math nan8365523
Ref: 6668365523
Ref: Constants<2>-Footnote-18367475
Ref: Constants<2>-Footnote-28367511
Ref: Constants<2>-Footnote-38367539
Node: cmath — Mathematical functions for complex numbers8367586
Ref: library/cmath doc8367817
Ref: 27e08367817
Ref: library/cmath cmath-mathematical-functions-for-complex-numbers8367817
Ref: 27e18367817
Ref: library/cmath module-cmath8367817
Ref: 188367817
Ref: library/cmath translation-repo8367817
Ref: 27e28367817
Node: Conversions to and from polar coordinates8376154
Ref: library/cmath conversions-to-and-from-polar-coordinates8376324
Ref: 27fb8376324
Ref: library/cmath cmath phase8377129
Ref: 27e48377129
Ref: library/cmath cmath polar8377895
Ref: 27e58377895
Ref: library/cmath cmath rect8378150
Ref: 27e68378150
Node: Power and logarithmic functions8378331
Ref: library/cmath power-and-logarithmic-functions8378536
Ref: 27fc8378536
Ref: library/cmath cmath exp8378617
Ref: 27e78378617
Ref: library/cmath cmath log8378738
Ref: 27e88378738
Ref: library/cmath cmath log108378982
Ref: 27e98378982
Ref: library/cmath cmath sqrt8379113
Ref: 27e38379113
Node: Trigonometric functions<2>8379237
Ref: library/cmath trigonometric-functions8379424
Ref: 27fd8379424
Ref: library/cmath cmath acos8379489
Ref: 27ea8379489
Ref: library/cmath cmath asin8379707
Ref: 27eb8379707
Ref: library/cmath cmath atan8379830
Ref: 27ec8379830
Ref: library/cmath cmath cos8380076
Ref: 27ed8380076
Ref: library/cmath cmath sin8380137
Ref: 27ee8380137
Ref: library/cmath cmath tan8380196
Ref: 27ef8380196
Node: Hyperbolic functions<2>8380258
Ref: library/cmath hyperbolic-functions8380438
Ref: 27fe8380438
Ref: library/cmath cmath acosh8380497
Ref: 27f08380497
Ref: library/cmath cmath asinh8380661
Ref: 27f18380661
Ref: library/cmath cmath atanh8380920
Ref: 27f28380920
Ref: library/cmath cmath cosh8381168
Ref: 27f38381168
Ref: library/cmath cmath sinh8381241
Ref: 27f48381241
Ref: library/cmath cmath tanh8381312
Ref: 27f58381312
Node: Classification functions8381386
Ref: library/cmath classification-functions8381552
Ref: 27ff8381552
Ref: library/cmath cmath isfinite8381619
Ref: 27f68381619
Ref: library/cmath cmath isinf8381793
Ref: 27f78381793
Ref: library/cmath cmath isnan8381944
Ref: 27f88381944
Ref: library/cmath cmath isclose8382089
Ref: ddf8382089
Ref: Classification functions-Footnote-18383720
Node: Constants<3>8383762
Ref: library/cmath constants8383896
Ref: 28008383896
Ref: library/cmath cmath pi8383933
Ref: 27f98383933
Ref: library/cmath cmath e8384003
Ref: 27fa8384003
Ref: library/cmath cmath tau8384071
Ref: ca48384071
Ref: library/cmath cmath inf8384170
Ref: ca58384170
Ref: library/cmath cmath infj8384294
Ref: ca88384294
Ref: library/cmath cmath nan8384477
Ref: ca68384477
Ref: library/cmath cmath nanj8384652
Ref: ca98384652
Node: decimal — Decimal fixed-point and floating-point arithmetic8386060
Ref: library/decimal doc8386290
Ref: 28018386290
Ref: library/decimal decimal-decimal-fixed-point-and-floating-point-arithmetic8386290
Ref: 28028386290
Ref: library/decimal module-decimal8386290
Ref: 368386290
Ref: library/decimal translation-repo8386290
Ref: 28038386290
Ref: decimal — Decimal fixed-point and floating-point arithmetic-Footnote-18391413
Ref: decimal — Decimal fixed-point and floating-point arithmetic-Footnote-28391480
Ref: decimal — Decimal fixed-point and floating-point arithmetic-Footnote-38391543
Node: Quick-start tutorial8391597
Ref: library/decimal decimal-tutorial8391739
Ref: 28138391739
Ref: library/decimal quick-start-tutorial8391739
Ref: 28148391739
Node: Decimal objects8399596
Ref: library/decimal decimal-decimal8399762
Ref: 28178399762
Ref: library/decimal decimal-objects8399762
Ref: 28188399762
Ref: library/decimal decimal Decimal8399811
Ref: 29d8399811
Ref: library/decimal decimal Decimal adjusted8405034
Ref: 28198405034
Ref: library/decimal decimal Decimal as_integer_ratio8405385
Ref: cb98405385
Ref: library/decimal decimal Decimal as_tuple8405820
Ref: 281a8405820
Ref: library/decimal decimal Decimal canonical8405978
Ref: 281b8405978
Ref: library/decimal decimal Decimal compare8406211
Ref: 281c8406211
Ref: library/decimal decimal Decimal compare_signal8406637
Ref: 281d8406637
Ref: library/decimal decimal Decimal compare_total8406949
Ref: 281e8406949
Ref: library/decimal decimal Decimal compare_total_mag8408214
Ref: 281f8408214
Ref: library/decimal decimal Decimal conjugate8408819
Ref: 28208408819
Ref: library/decimal decimal Decimal copy_abs8408952
Ref: 28218408952
Ref: library/decimal decimal Decimal copy_negate8409166
Ref: 28228409166
Ref: library/decimal decimal Decimal copy_sign8409377
Ref: 28238409377
Ref: library/decimal decimal Decimal exp8409914
Ref: 10ee8409914
Ref: library/decimal decimal Decimal from_float8410348
Ref: 12498410348
Ref: library/decimal decimal Decimal fma8411470
Ref: 28248411470
Ref: library/decimal decimal Decimal is_canonical8411714
Ref: 28258411714
Ref: library/decimal decimal Decimal is_finite8411968
Ref: 28268411968
Ref: library/decimal decimal Decimal is_infinite8412143
Ref: 28278412143
Ref: library/decimal decimal Decimal is_nan8412310
Ref: 28288412310
Ref: library/decimal decimal Decimal is_normal8412462
Ref: 28298412462
Ref: library/decimal decimal Decimal is_qnan8412686
Ref: 282a8412686
Ref: library/decimal decimal Decimal is_signed8412825
Ref: 282b8412825
Ref: library/decimal decimal Decimal is_snan8413028
Ref: 282c8413028
Ref: library/decimal decimal Decimal is_subnormal8413170
Ref: 282d8413170
Ref: library/decimal decimal Decimal is_zero8413324
Ref: 282e8413324
Ref: library/decimal decimal Decimal ln8413480
Ref: 10ef8413480
Ref: library/decimal decimal Decimal log108413688
Ref: 282f8413688
Ref: library/decimal decimal Decimal logb8413891
Ref: 28308413891
Ref: library/decimal decimal Decimal logical_and8414272
Ref: 28318414272
Ref: library/decimal decimal Decimal logical_invert8414531
Ref: 28338414531
Ref: library/decimal decimal Decimal logical_or8414703
Ref: 28348414703
Ref: library/decimal decimal Decimal logical_xor8414959
Ref: 28358414959
Ref: library/decimal decimal Decimal max8415221
Ref: 28368415221
Ref: library/decimal decimal Decimal max_mag8415525
Ref: 28378415525
Ref: library/decimal decimal Decimal min8415706
Ref: 28388415706
Ref: library/decimal decimal Decimal min_mag8416010
Ref: 28398416010
Ref: library/decimal decimal Decimal next_minus8416191
Ref: 283a8416191
Ref: library/decimal decimal Decimal next_plus8416429
Ref: 283b8416429
Ref: library/decimal decimal Decimal next_toward8416666
Ref: 283c8416666
Ref: library/decimal decimal Decimal normalize8417033
Ref: 283d8417033
Ref: library/decimal decimal Decimal number_class8418079
Ref: 283e8418079
Ref: library/decimal decimal Decimal quantize8419249
Ref: 10f48419249
Ref: library/decimal decimal Decimal radix8420568
Ref: 28408420568
Ref: library/decimal decimal Decimal remainder_near8420779
Ref: 28418420779
Ref: library/decimal decimal Decimal rotate8421623
Ref: 28428421623
Ref: library/decimal decimal Decimal same_quantum8422296
Ref: 28438422296
Ref: library/decimal decimal Decimal scaleb8422708
Ref: 28448422708
Ref: library/decimal decimal Decimal shift8422959
Ref: 28458422959
Ref: library/decimal decimal Decimal sqrt8423565
Ref: 28468423565
Ref: library/decimal decimal Decimal to_eng_string8423672
Ref: 28478423672
Ref: library/decimal decimal Decimal to_integral8424148
Ref: 28488424148
Ref: library/decimal decimal Decimal to_integral_exact8424378
Ref: 284a8424378
Ref: library/decimal decimal Decimal to_integral_value8424808
Ref: 28498424808
Node: Logical operands8427298
Ref: library/decimal logical-operands8427366
Ref: 284b8427366
Ref: library/decimal logical-operands-label8427366
Ref: 28328427366
Node: Context objects8427739
Ref: library/decimal context-objects8427897
Ref: 284c8427897
Ref: library/decimal decimal-context8427897
Ref: 249d8427897
Ref: library/decimal decimal getcontext8428281
Ref: 16dc8428281
Ref: library/decimal decimal setcontext8428374
Ref: 28158428374
Ref: library/decimal decimal localcontext8428611
Ref: 13d38428611
Ref: library/decimal decimal BasicContext8430224
Ref: 10e88430224
Ref: library/decimal decimal ExtendedContext8430675
Ref: 10e98430675
Ref: library/decimal decimal DefaultContext8431307
Ref: 10e78431307
Ref: library/decimal decimal Context8432440
Ref: 10f38432440
Ref: library/decimal decimal Context prec8432821
Ref: 284d8432821
Ref: library/decimal decimal Context rounding8432991
Ref: 284e8432991
Ref: library/decimal decimal Context traps8433113
Ref: 10f28433113
Ref: library/decimal decimal Context flags8433139
Ref: 10f18433139
Ref: library/decimal decimal Context Emin8433293
Ref: 10eb8433293
Ref: library/decimal decimal Context Emax8433318
Ref: 10ea8433318
Ref: library/decimal decimal Context capitals8433552
Ref: 28508433552
Ref: library/decimal decimal Context clamp8433787
Ref: 11e28433787
Ref: library/decimal decimal Context clear_flags8435542
Ref: 28168435542
Ref: library/decimal decimal Context clear_traps8435622
Ref: 28518435622
Ref: library/decimal decimal Context copy8435735
Ref: 28528435735
Ref: library/decimal decimal Context copy_decimal8435807
Ref: 28538435807
Ref: library/decimal decimal Context create_decimal8435901
Ref: 10ed8435901
Ref: library/decimal decimal Context create_decimal_from_float8437012
Ref: 28548437012
Ref: library/decimal decimal Context Etiny8437781
Ref: 283f8437781
Ref: library/decimal decimal Context Etop8438011
Ref: 28558438011
Ref: library/decimal decimal Context abs8438511
Ref: 28568438511
Ref: library/decimal decimal Context add8438586
Ref: 28578438586
Ref: library/decimal decimal Context canonical8438660
Ref: 13508438660
Ref: library/decimal decimal Context compare8438743
Ref: 28588438743
Ref: library/decimal decimal Context compare_signal8438824
Ref: 28598438824
Ref: library/decimal decimal Context compare_total8438931
Ref: 285a8438931
Ref: library/decimal decimal Context compare_total_mag8439043
Ref: 285b8439043
Ref: library/decimal decimal Context copy_abs8439184
Ref: 285c8439184
Ref: library/decimal decimal Context copy_negate8439275
Ref: 285d8439275
Ref: library/decimal decimal Context copy_sign8439369
Ref: 285e8439369
Ref: library/decimal decimal Context divide8439451
Ref: 285f8439451
Ref: library/decimal decimal Context divide_int8439524
Ref: 28608439524
Ref: library/decimal decimal Context divmod8439626
Ref: 28618439626
Ref: library/decimal decimal Context exp8439746
Ref: 28628439746
Ref: library/decimal decimal Context fma8439808
Ref: 28638439808
Ref: library/decimal decimal Context is_canonical8439895
Ref: 13518439895
Ref: library/decimal decimal Context is_finite8440015
Ref: 28648440015
Ref: library/decimal decimal Context is_infinite8440129
Ref: 28658440129
Ref: library/decimal decimal Context is_nan8440247
Ref: 28668440247
Ref: library/decimal decimal Context is_normal8440376
Ref: 28678440376
Ref: library/decimal decimal Context is_qnan8440509
Ref: 28688440509
Ref: library/decimal decimal Context is_signed8440636
Ref: 28698440636
Ref: library/decimal decimal Context is_snan8440752
Ref: 286a8440752
Ref: library/decimal decimal Context is_subnormal8440883
Ref: 286b8440883
Ref: library/decimal decimal Context is_zero8441003
Ref: 286c8441003
Ref: library/decimal decimal Context ln8441115
Ref: 286d8441115
Ref: library/decimal decimal Context log108441201
Ref: 286e8441201
Ref: library/decimal decimal Context logb8441281
Ref: 286f8441281
Ref: library/decimal decimal Context logical_and8441384
Ref: 28708441384
Ref: library/decimal decimal Context logical_invert8441514
Ref: 28718441514
Ref: library/decimal decimal Context logical_or8441595
Ref: 28728441595
Ref: library/decimal decimal Context logical_xor8441723
Ref: 28738441723
Ref: library/decimal decimal Context max8441853
Ref: 28748441853
Ref: library/decimal decimal Context max_mag8441953
Ref: 28758441953
Ref: library/decimal decimal Context min8442057
Ref: 28768442057
Ref: library/decimal decimal Context min_mag8442157
Ref: 28778442157
Ref: library/decimal decimal Context minus8442261
Ref: 28788442261
Ref: library/decimal decimal Context multiply8442377
Ref: 28798442377
Ref: library/decimal decimal Context next_minus8442460
Ref: 287a8442460
Ref: library/decimal decimal Context next_plus8442566
Ref: 287b8442566
Ref: library/decimal decimal Context next_toward8442671
Ref: 287c8442671
Ref: library/decimal decimal Context normalize8442783
Ref: 287d8442783
Ref: library/decimal decimal Context number_class8442863
Ref: 287e8442863
Ref: library/decimal decimal Context plus8442955
Ref: 287f8442955
Ref: library/decimal decimal Context power8443175
Ref: 28808443175
Ref: library/decimal decimal Context quantize8444978
Ref: 28818444978
Ref: library/decimal decimal Context radix8445104
Ref: 28828445104
Ref: library/decimal decimal Context remainder8445182
Ref: 28838445182
Ref: library/decimal decimal Context remainder_near8445380
Ref: 28848445380
Ref: library/decimal decimal Context rotate8445603
Ref: 28858445603
Ref: library/decimal decimal Context same_quantum8445691
Ref: 28868445691
Ref: library/decimal decimal Context scaleb8445806
Ref: 28878445806
Ref: library/decimal decimal Context shift8445927
Ref: 28888445927
Ref: library/decimal decimal Context sqrt8446014
Ref: 28898446014
Ref: library/decimal decimal Context subtract8446114
Ref: 288a8446114
Ref: library/decimal decimal Context to_eng_string8446205
Ref: 288b8446205
Ref: library/decimal decimal Context to_integral_exact8446572
Ref: 288c8446572
Ref: library/decimal decimal Context to_sci_string8446648
Ref: 288d8446648
Node: Constants<4>8446755
Ref: library/decimal constants8446912
Ref: 288e8446912
Ref: library/decimal decimal-rounding-modes8446912
Ref: 288f8446912
Ref: library/decimal decimal MAX_PREC8447349
Ref: 10e48447349
Ref: library/decimal decimal MAX_EMAX8447484
Ref: 10e58447484
Ref: library/decimal decimal MIN_EMIN8447619
Ref: 10e68447619
Ref: library/decimal decimal MIN_ETINY8447755
Ref: 28908447755
Ref: library/decimal decimal HAVE_THREADS8447883
Ref: 10e28447883
Ref: library/decimal decimal HAVE_CONTEXTVAR8448039
Ref: 1f1a8448039
Node: Rounding modes8448402
Ref: library/decimal rounding-modes8448551
Ref: 284f8448551
Ref: library/decimal decimal ROUND_CEILING8448598
Ref: 28048448598
Ref: library/decimal decimal ROUND_DOWN8448667
Ref: 28058448667
Ref: library/decimal decimal ROUND_FLOOR8448723
Ref: 28068448723
Ref: library/decimal decimal ROUND_HALF_DOWN8448791
Ref: 28078448791
Ref: library/decimal decimal ROUND_HALF_EVEN8448879
Ref: 28088448879
Ref: library/decimal decimal ROUND_HALF_UP8448978
Ref: 28098448978
Ref: library/decimal decimal ROUND_UP8449066
Ref: 280a8449066
Ref: library/decimal decimal ROUND_05UP8449122
Ref: 280b8449122
Node: Signals8449280
Ref: library/decimal decimal-signals8449437
Ref: 28918449437
Ref: library/decimal signals8449437
Ref: 28928449437
Ref: library/decimal decimal Clamped8450154
Ref: 280c8450154
Ref: library/decimal decimal DecimalException8450467
Ref: 28938450467
Ref: library/decimal decimal DivisionByZero8450591
Ref: 280d8450591
Ref: library/decimal decimal Inexact8450929
Ref: 280e8450929
Ref: library/decimal decimal InvalidOperation8451204
Ref: 10ec8451204
Ref: library/decimal decimal Overflow8451645
Ref: 28118451645
Ref: library/decimal decimal Rounded8452068
Ref: 280f8452068
Ref: library/decimal decimal Subnormal8452406
Ref: 28108452406
Ref: library/decimal decimal Underflow8452635
Ref: 28128452635
Ref: library/decimal decimal FloatOperation8452860
Ref: 10e18452860
Node: Floating-point notes8454118
Ref: library/decimal decimal-notes8454281
Ref: 28948454281
Ref: library/decimal floating-point-notes8454281
Ref: 28958454281
Node: Mitigating round-off error with increased precision8454425
Ref: library/decimal mitigating-round-off-error-with-increased-precision8454556
Ref: 28968454556
Node: Special values8456240
Ref: library/decimal special-values8456371
Ref: 28978456371
Node: Working with threads8459497
Ref: library/decimal decimal-threads8459660
Ref: 28988459660
Ref: library/decimal working-with-threads8459660
Ref: 28998459660
Node: Recipes8461027
Ref: library/decimal decimal-recipes8461181
Ref: 289a8461181
Ref: library/decimal recipes8461181
Ref: 289b8461181
Node: Decimal FAQ8466026
Ref: library/decimal decimal-faq8466151
Ref: 289c8466151
Ref: library/decimal id18466151
Ref: 289d8466151
Ref: Decimal FAQ-Footnote-18475163
Ref: Decimal FAQ-Footnote-28475230
Ref: Decimal FAQ-Footnote-38475261
Ref: Decimal FAQ-Footnote-48475319
Ref: Decimal FAQ-Footnote-58475422
Node: fractions — Rational numbers8475532
Ref: library/fractions doc8475751
Ref: 289e8475751
Ref: library/fractions fractions-rational-numbers8475751
Ref: 289f8475751
Ref: library/fractions module-fractions8475751
Ref: 5d8475751
Ref: library/fractions translation-repo8475751
Ref: 28a08475751
Ref: library/fractions fractions Fraction8476126
Ref: 1e78476126
Ref: library/fractions fractions Fraction numerator8480397
Ref: 28a28480397
Ref: library/fractions fractions Fraction denominator8480481
Ref: 28a38480481
Ref: library/fractions fractions Fraction as_integer_ratio8480608
Ref: 28a48480608
Ref: library/fractions fractions Fraction is_integer8480851
Ref: 28a58480851
Ref: library/fractions fractions Fraction from_float8480977
Ref: 124a8480977
Ref: library/fractions fractions Fraction from_decimal8481407
Ref: 124b8481407
Ref: library/fractions fractions Fraction limit_denominator8481774
Ref: 28a18481774
Ref: library/fractions fractions Fraction __floor__8482642
Ref: 189a8482642
Ref: library/fractions fractions Fraction __ceil__8482943
Ref: 18998482943
Ref: library/fractions fractions Fraction __round__8483134
Ref: 18988483134
Ref: library/fractions fractions Fraction __format__8483605
Ref: 28a68483605
Ref: fractions — Rational numbers-Footnote-18485916
Ref: fractions — Rational numbers-Footnote-28485985
Node: random — Generate pseudo-random numbers8486027
Ref: library/random doc8486233
Ref: 28a78486233
Ref: library/random module-random8486233
Ref: b88486233
Ref: library/random random-generate-pseudo-random-numbers8486233
Ref: 28a88486233
Ref: library/random translation-repo8486233
Ref: 28a98486233
Ref: random — Generate pseudo-random numbers-Footnote-18489492
Ref: random — Generate pseudo-random numbers-Footnote-28489558
Node: Bookkeeping functions8489648
Ref: library/random bookkeeping-functions8489775
Ref: 28ab8489775
Ref: library/random random seed8489836
Ref: 12ba8489836
Ref: library/random random getstate8490935
Ref: 28ac8490935
Ref: library/random random setstate8491133
Ref: 28ad8491133
Node: Functions for bytes8491392
Ref: library/random functions-for-bytes8491550
Ref: 28ae8491550
Ref: library/random random randbytes8491607
Ref: 16488491607
Node: Functions for integers8491827
Ref: library/random functions-for-integers8491987
Ref: 28b08491987
Ref: library/random random randrange8492050
Ref: 8728492050
Ref: library/random random randint8493109
Ref: 12758493109
Ref: library/random random getrandbits8493250
Ref: 10488493250
Node: Functions for sequences8493693
Ref: library/random functions-for-sequences8493856
Ref: 28b18493856
Ref: library/random random choice8493921
Ref: 12768493921
Ref: library/random random choices8494077
Ref: cec8494077
Ref: library/random random shuffle8496106
Ref: 74a8496106
Ref: library/random random sample8496767
Ref: 7498496767
Node: Discrete distributions8498304
Ref: library/random discrete-distributions8498470
Ref: 28b28498470
Ref: library/random random binomialvariate8498592
Ref: 4b38498592
Ref: Discrete distributions-Footnote-18499154
Node: Real-valued distributions8499218
Ref: library/random id18499382
Ref: 28b38499382
Ref: library/random real-valued-distributions8499382
Ref: 28b48499382
Ref: library/random random random8499721
Ref: 74b8499721
Ref: library/random random uniform8499843
Ref: 28b58499843
Ref: library/random random triangular8500184
Ref: 28b68500184
Ref: library/random random betavariate8500541
Ref: 28b78500541
Ref: library/random random expovariate8500729
Ref: 4b48500729
Ref: library/random random gammavariate8501184
Ref: 28b88501184
Ref: library/random random gauss8501697
Ref: 197d8501697
Ref: library/random random lognormvariate8502446
Ref: 28b98502446
Ref: library/random random normalvariate8502745
Ref: 197e8502745
Ref: library/random random vonmisesvariate8502972
Ref: 28ba8502972
Ref: library/random random paretovariate8503314
Ref: 28bb8503314
Ref: library/random random weibullvariate8503418
Ref: 28bc8503418
Node: Alternative Generator8503569
Ref: library/random alternative-generator8503735
Ref: 28bd8503735
Ref: library/random random Random8503796
Ref: 1a028503796
Ref: library/random random Random seed8504292
Ref: 1b138504292
Ref: library/random random Random getstate8504465
Ref: 28be8504465
Ref: library/random random Random setstate8504629
Ref: 28bf8504629
Ref: library/random random Random random8504798
Ref: 28c08504798
Ref: library/random random Random getrandbits8505046
Ref: 28c18505046
Ref: library/random random Random randbytes8505217
Ref: 9338505217
Ref: library/random random SystemRandom8505384
Ref: 28aa8505384
Node: Notes on Reproducibility8505882
Ref: library/random notes-on-reproducibility8506034
Ref: 28c28506034
Node: Examples<4>8506743
Ref: library/random examples8506884
Ref: 28c38506884
Ref: library/random random-examples8506884
Ref: 12218506884
Ref: Examples<4>-Footnote-18512133
Ref: Examples<4>-Footnote-28512198
Ref: Examples<4>-Footnote-38512279
Ref: Examples<4>-Footnote-48512325
Ref: Examples<4>-Footnote-58512377
Ref: Examples<4>-Footnote-68512432
Ref: Examples<4>-Footnote-78512500
Ref: Examples<4>-Footnote-88512536
Ref: Examples<4>-Footnote-98512606
Node: Recipes<2>8512642
Ref: library/random recipes8512777
Ref: 28c48512777
Ref: Recipes<2>-Footnote-18516519
Node: Command-line usage8516587
Ref: library/random command-line-usage8516731
Ref: 28c58516731
Ref: library/random random-cli8516731
Ref: 1548516731
Ref: library/random cmdoption-random-h8516992
Ref: 28c68516992
Ref: library/random cmdoption-random-help8516992
Ref: 28c78516992
Ref: library/random cmdoption-random-c8517054
Ref: 28c88517054
Ref: library/random cmdoption-random-choice8517089
Ref: 28c98517089
Ref: library/random cmdoption-random-i8517188
Ref: 28ca8517188
Ref: library/random cmdoption-random-integer8517207
Ref: 28cb8517207
Ref: library/random cmdoption-random-f8517324
Ref: 28cc8517324
Ref: library/random cmdoption-random-float8517343
Ref: 28cd8517343
Node: Command-line example8517672
Ref: library/random command-line-example8517797
Ref: 28ce8517797
Ref: library/random random-cli-example8517797
Ref: 28cf8517797
Node: statistics — Mathematical statistics functions8518626
Ref: library/statistics doc8518793
Ref: 28d08518793
Ref: library/statistics module-statistics8518793
Ref: d28518793
Ref: library/statistics statistics-mathematical-statistics-functions8518793
Ref: 28d18518793
Ref: library/statistics translation-repo8518793
Ref: 28d28518793
Ref: statistics — Mathematical statistics functions-Footnote-18521345
Ref: statistics — Mathematical statistics functions-Footnote-28521415
Ref: statistics — Mathematical statistics functions-Footnote-38521441
Node: Averages and measures of central location8521468
Ref: library/statistics averages-and-measures-of-central-location8521621
Ref: 28d38521621
Node: Measures of spread8523446
Ref: library/statistics measures-of-spread8523651
Ref: 28d88523651
Node: Statistics for relations between two inputs8524277
Ref: library/statistics statistics-for-relations-between-two-inputs8524457
Ref: 28da8524457
Node: Function details8525025
Ref: library/statistics function-details8525200
Ref: 28db8525200
Ref: library/statistics statistics mean8525402
Ref: 6d58525402
Ref: library/statistics statistics fmean8526951
Ref: a418526951
Ref: library/statistics statistics geometric_mean8527902
Ref: a428527902
Ref: library/statistics statistics harmonic_mean8528591
Ref: d088528591
Ref: library/statistics statistics kde8530150
Ref: 24a8530150
Ref: library/statistics statistics kde_random8532028
Ref: 24b8532028
Ref: library/statistics statistics median8533077
Ref: 28d48533077
Ref: library/statistics statistics median_low8534072
Ref: 28d58534072
Ref: library/statistics statistics median_high8534713
Ref: 28d68534713
Ref: library/statistics statistics median_grouped8535351
Ref: 28d78535351
Ref: library/statistics statistics mode8537255
Ref: aa38537255
Ref: library/statistics statistics multimode8538774
Ref: a438538774
Ref: library/statistics statistics pstdev8539195
Ref: 15f88539195
Ref: library/statistics statistics pvariance8539495
Ref: 28d98539495
Ref: library/statistics statistics stdev8541770
Ref: 6d78541770
Ref: library/statistics statistics variance8542061
Ref: 6d68542061
Ref: library/statistics statistics quantiles8544347
Ref: a448544347
Ref: library/statistics statistics covariance8547331
Ref: 8368547331
Ref: library/statistics statistics correlation8547952
Ref: 4bf8547952
Ref: library/statistics statistics linear_regression8550044
Ref: 8378550044
Ref: Function details-Footnote-18552629
Ref: Function details-Footnote-28552675
Ref: Function details-Footnote-38552730
Ref: Function details-Footnote-48552826
Ref: Function details-Footnote-58552884
Ref: Function details-Footnote-68552956
Ref: Function details-Footnote-78553007
Ref: Function details-Footnote-88553077
Ref: Function details-Footnote-98553158
Ref: Function details-Footnote-108553230
Ref: Function details-Footnote-118553294
Node: Exceptions<5>8553352
Ref: library/statistics exceptions8553502
Ref: 28dd8553502
Ref: library/statistics statistics StatisticsError8553573
Ref: 28dc8553573
Node: NormalDist objects8553697
Ref: library/statistics normaldist-objects8553854
Ref: 28de8553854
Ref: library/statistics statistics NormalDist8554242
Ref: a458554242
Ref: library/statistics statistics NormalDist mean8554507
Ref: 28df8554507
Ref: library/statistics statistics NormalDist median8554628
Ref: 28e08554628
Ref: library/statistics statistics NormalDist mode8554742
Ref: 28e18554742
Ref: library/statistics statistics NormalDist stdev8554842
Ref: 28e28554842
Ref: library/statistics statistics NormalDist variance8554967
Ref: 28e38554967
Ref: library/statistics statistics NormalDist from_samples8555133
Ref: 28e48555133
Ref: library/statistics statistics NormalDist samples8555741
Ref: 28e58555741
Ref: library/statistics statistics NormalDist pdf8556354
Ref: 28e68556354
Ref: library/statistics statistics NormalDist cdf8556955
Ref: 28e78556955
Ref: library/statistics statistics NormalDist inv_cdf8557198
Ref: 28e88557198
Ref: library/statistics statistics NormalDist overlap8557637
Ref: 28e98557637
Ref: library/statistics statistics NormalDist quantiles8557893
Ref: 28ea8557893
Ref: library/statistics statistics NormalDist zscore8558348
Ref: 28eb8558348
Ref: NormalDist objects-Footnote-18559756
Ref: NormalDist objects-Footnote-28559820
Ref: NormalDist objects-Footnote-38559880
Ref: NormalDist objects-Footnote-48559934
Ref: NormalDist objects-Footnote-58559991
Ref: NormalDist objects-Footnote-68560045
Ref: NormalDist objects-Footnote-78560090
Ref: NormalDist objects-Footnote-88560146
Ref: NormalDist objects-Footnote-98560203
Ref: NormalDist objects-Footnote-108560250
Ref: NormalDist objects-Footnote-118560318
Ref: NormalDist objects-Footnote-128560390
Ref: NormalDist objects-Footnote-138560447
Ref: NormalDist objects-Footnote-148560582
Ref: NormalDist objects-Footnote-158560629
Ref: NormalDist objects-Footnote-168560707
Node: Examples and Recipes<2>8560792
Ref: library/statistics examples-and-recipes8560927
Ref: 28ec8560927
Node: Classic probability problems8561139
Ref: library/statistics classic-probability-problems8561270
Ref: 28ed8561270
Ref: Classic probability problems-Footnote-18562097
Ref: Classic probability problems-Footnote-28562168
Ref: Classic probability problems-Footnote-38562215
Node: Monte Carlo inputs for simulations8562260
Ref: library/statistics monte-carlo-inputs-for-simulations8562436
Ref: 28ee8562436
Ref: Monte Carlo inputs for simulations-Footnote-18563126
Node: Approximating binomial distributions8563183
Ref: library/statistics approximating-binomial-distributions8563356
Ref: 28ef8563356
Ref: Approximating binomial distributions-Footnote-18564788
Node: Naive bayesian classifier8564852
Ref: library/statistics naive-bayesian-classifier8564982
Ref: 28f08564982
Ref: Naive bayesian classifier-Footnote-18566877
Ref: Naive bayesian classifier-Footnote-28566961
Ref: Naive bayesian classifier-Footnote-38567017
Node: Functional Programming Modules8567087
Ref: library/functional doc8567256
Ref: 28f18567256
Ref: library/functional functional-programming-modules8567256
Ref: 28f28567256
Ref: library/functional translation-repo8567256
Ref: 28f38567256
Node: itertools — Functions creating iterators for efficient looping8567739
Ref: library/itertools doc8567950
Ref: 28f48567950
Ref: library/itertools itertools-functions-creating-iterators-for-efficient-looping8567950
Ref: 28f58567950
Ref: library/itertools module-itertools8567950
Ref: 818567950
Node: Itertool Functions8578999
Ref: library/itertools itertool-functions8579144
Ref: 28fc8579144
Ref: library/itertools itertools-functions8579144
Ref: 28fd8579144
Ref: library/itertools itertools accumulate8579384
Ref: a088579384
Ref: library/itertools itertools batched8581801
Ref: 2018581801
Ref: library/itertools itertools chain8583132
Ref: 23388583132
Ref: library/itertools itertools chain from_iterable8583611
Ref: 28f88583611
Ref: library/itertools itertools combinations8584021
Ref: 135b8584021
Ref: library/itertools itertools combinations_with_replacement8585633
Ref: 12c88585633
Ref: library/itertools itertools compress8587217
Ref: 12c98587217
Ref: library/itertools itertools count8587714
Ref: 12ca8587714
Ref: library/itertools itertools cycle8588531
Ref: 28f68588531
Ref: library/itertools itertools dropwhile8589234
Ref: 28f98589234
Ref: library/itertools itertools filterfalse8589941
Ref: 23268589941
Ref: library/itertools itertools groupby8590526
Ref: 15aa8590526
Ref: library/itertools itertools islice8593124
Ref: b678593124
Ref: library/itertools itertools pairwise8594892
Ref: 81b8594892
Ref: library/itertools itertools permutations8595509
Ref: 1a848595509
Ref: library/itertools itertools product8597578
Ref: 135c8597578
Ref: library/itertools itertools repeat8599277
Ref: 28f78599277
Ref: library/itertools itertools starmap8599963
Ref: 11288599963
Ref: library/itertools itertools takewhile8600603
Ref: 28fa8600603
Ref: library/itertools itertools tee8601406
Ref: 28fb8601406
Ref: library/itertools itertools zip_longest8604099
Ref: 12e58604099
Ref: Itertool Functions-Footnote-18605601
Ref: Itertool Functions-Footnote-28605675
Ref: Itertool Functions-Footnote-38605730
Ref: Itertool Functions-Footnote-48605786
Node: Itertools Recipes8605884
Ref: library/itertools id18606029
Ref: 28ff8606029
Ref: library/itertools itertools-recipes8606029
Ref: 12a58606029
Ref: Itertools Recipes-Footnote-18619825
Ref: Itertools Recipes-Footnote-28619874
Node: functools — Higher-order functions and operations on callable objects8619945
Ref: library/functools doc8620209
Ref: 29008620209
Ref: library/functools functools-higher-order-functions-and-operations-on-callable-objects8620209
Ref: 29018620209
Ref: library/functools module-functools8620209
Ref: 5f8620209
Ref: library/functools translation-repo8620209
Ref: 29028620209
Ref: library/functools functools cache8620742
Ref: 16278620742
Ref: library/functools functools cached_property8621969
Ref: 5448621969
Ref: library/functools functools cmp_to_key8625255
Ref: 121f8625255
Ref: library/functools functools lru_cache8626306
Ref: 9fa8626306
Ref: library/functools functools lru_cache cache_info8628832
Ref: 29048628832
Ref: library/functools functools lru_cache cache_clear8629097
Ref: 29058629097
Ref: library/functools functools total_ordering8631826
Ref: f7a8631826
Ref: library/functools functools partial8634067
Ref: 4178634067
Ref: library/functools functools partialmethod8635439
Ref: a8a8635439
Ref: library/functools functools reduce8637156
Ref: 13248637156
Ref: library/functools functools singledispatch8638406
Ref: 63c8638406
Ref: library/functools functools singledispatch register8639010
Ref: 29078639010
Ref: library/functools functools singledispatchmethod8644912
Ref: 9fb8644912
Ref: library/functools functools update_wrapper8646630
Ref: 105d8646630
Ref: library/functools functools wraps8649212
Ref: f968649212
Ref: functools — Higher-order functions and operations on callable objects-Footnote-18650511
Ref: functools — Higher-order functions and operations on callable objects-Footnote-28650580
Ref: functools — Higher-order functions and operations on callable objects-Footnote-38650630
Ref: functools — Higher-order functions and operations on callable objects-Footnote-48650672
Ref: functools — Higher-order functions and operations on callable objects-Footnote-58650764
Ref: functools — Higher-order functions and operations on callable objects-Footnote-68650819
Ref: functools — Higher-order functions and operations on callable objects-Footnote-78650877
Node: partial Objects8650942
Ref: library/functools id18651065
Ref: 29098651065
Ref: library/functools partial-objects8651065
Ref: 29068651065
Ref: library/functools functools partial func8651246
Ref: 290a8651246
Ref: library/functools functools partial args8651435
Ref: 290b8651435
Ref: library/functools functools partial keywords8651607
Ref: 290c8651607
Node: operator — Standard operators as functions8652186
Ref: library/operator doc8652377
Ref: 290d8652377
Ref: library/operator module-operator8652377
Ref: 9f8652377
Ref: library/operator operator-standard-operators-as-functions8652377
Ref: 290e8652377
Ref: library/operator translation-repo8652377
Ref: 290f8652377
Ref: library/operator operator lt8653305
Ref: 29108653305
Ref: library/operator operator le8653338
Ref: 29118653338
Ref: library/operator operator eq8653371
Ref: 29128653371
Ref: library/operator operator ne8653404
Ref: 29138653404
Ref: library/operator operator ge8653437
Ref: 29148653437
Ref: library/operator operator gt8653470
Ref: 29158653470
Ref: library/operator operator __lt__8653503
Ref: 29168653503
Ref: library/operator operator __le__8653540
Ref: 29178653540
Ref: library/operator operator __eq__8653577
Ref: 29188653577
Ref: library/operator operator __ne__8653614
Ref: 29198653614
Ref: library/operator operator __ge__8653651
Ref: 291a8653651
Ref: library/operator operator __gt__8653688
Ref: 291b8653688
Ref: library/operator operator not_8654428
Ref: 291c8654428
Ref: library/operator operator __not__8654462
Ref: 291d8654462
Ref: library/operator operator truth8654778
Ref: 291e8654778
Ref: library/operator operator is_8654968
Ref: 291f8654968
Ref: library/operator operator is_not8655054
Ref: 29208655054
Ref: library/operator operator abs8655211
Ref: 29218655211
Ref: library/operator operator __abs__8655244
Ref: 29228655244
Ref: library/operator operator add8655324
Ref: 29238655324
Ref: library/operator operator __add__8655358
Ref: 29248655358
Ref: library/operator operator and_8655448
Ref: 29258655448
Ref: library/operator operator __and__8655483
Ref: 29268655483
Ref: library/operator operator floordiv8655567
Ref: 29278655567
Ref: library/operator operator __floordiv__8655606
Ref: 29288655606
Ref: library/operator operator index8655677
Ref: 1a788655677
Ref: library/operator operator __index__8655710
Ref: 29298655710
Ref: library/operator operator inv8655996
Ref: 292a8655996
Ref: library/operator operator invert8656029
Ref: 292b8656029
Ref: library/operator operator __inv__8656065
Ref: 292c8656065
Ref: library/operator operator __invert__8656102
Ref: 292d8656102
Ref: library/operator operator lshift8656237
Ref: 292e8656237
Ref: library/operator operator __lshift__8656274
Ref: 292f8656274
Ref: library/operator operator mod8656354
Ref: 29308656354
Ref: library/operator operator __mod__8656388
Ref: 29318656388
Ref: library/operator operator mul8656453
Ref: 28fe8656453
Ref: library/operator operator __mul__8656487
Ref: 29328656487
Ref: library/operator operator matmul8656577
Ref: e688656577
Ref: library/operator operator __matmul__8656614
Ref: 29338656614
Ref: library/operator operator neg8656710
Ref: 29348656710
Ref: library/operator operator __neg__8656743
Ref: 29358656743
Ref: library/operator operator or_8656822
Ref: 29368656822
Ref: library/operator operator __or__8656856
Ref: 29378656856
Ref: library/operator operator pos8656938
Ref: 29388656938
Ref: library/operator operator __pos__8656971
Ref: 29398656971
Ref: library/operator operator pow8657051
Ref: 293a8657051
Ref: library/operator operator __pow__8657085
Ref: 293b8657085
Ref: library/operator operator rshift8657176
Ref: 293c8657176
Ref: library/operator operator __rshift__8657213
Ref: 293d8657213
Ref: library/operator operator sub8657294
Ref: 293e8657294
Ref: library/operator operator __sub__8657328
Ref: 293f8657328
Ref: library/operator operator truediv8657393
Ref: 29408657393
Ref: library/operator operator __truediv__8657431
Ref: 29418657431
Ref: library/operator operator xor8657580
Ref: 29428657580
Ref: library/operator operator __xor__8657614
Ref: 29438657614
Ref: library/operator operator concat8657787
Ref: 29448657787
Ref: library/operator operator __concat__8657824
Ref: 29458657824
Ref: library/operator operator contains8657918
Ref: 8e38657918
Ref: library/operator operator __contains__8657957
Ref: 29468657957
Ref: library/operator operator countOf8658086
Ref: 8e58658086
Ref: library/operator operator delitem8658179
Ref: 29478658179
Ref: library/operator operator __delitem__8658217
Ref: 29488658217
Ref: library/operator operator getitem8658304
Ref: 29498658304
Ref: library/operator operator __getitem__8658342
Ref: 294a8658342
Ref: library/operator operator indexOf8658429
Ref: 8e48658429
Ref: library/operator operator setitem8658533
Ref: 294b8658533
Ref: library/operator operator __setitem__8658574
Ref: 294c8658574
Ref: library/operator operator length_hint8658668
Ref: fa68658668
Ref: library/operator operator call8659004
Ref: 19c68659004
Ref: library/operator operator __call__8659058
Ref: 294d8659058
Ref: library/operator operator attrgetter8659469
Ref: e668659469
Ref: library/operator operator itemgetter8660770
Ref: a708660770
Ref: library/operator operator methodcaller8662537
Ref: e678662537
Ref: operator — Standard operators as functions-Footnote-18663336
Node: Mapping Operators to Functions8663404
Ref: library/operator mapping-operators-to-functions8663542
Ref: 294e8663542
Ref: library/operator operator-map8663542
Ref: 294f8663542
Node: In-place Operators8670961
Ref: library/operator in-place-operators8671099
Ref: 29508671099
Ref: library/operator operator iadd8672407
Ref: 29528672407
Ref: library/operator operator __iadd__8672442
Ref: 29538672442
Ref: library/operator operator iand8672540
Ref: 29548672540
Ref: library/operator operator __iand__8672575
Ref: 29558672575
Ref: library/operator operator iconcat8672673
Ref: 29568672673
Ref: library/operator operator __iconcat__8672711
Ref: 29578672711
Ref: library/operator operator ifloordiv8672846
Ref: 29588672846
Ref: library/operator operator __ifloordiv__8672886
Ref: 29598672886
Ref: library/operator operator ilshift8672995
Ref: 295a8672995
Ref: library/operator operator __ilshift__8673033
Ref: 295b8673033
Ref: library/operator operator imod8673138
Ref: 295c8673138
Ref: library/operator operator __imod__8673173
Ref: 295d8673173
Ref: library/operator operator imul8673271
Ref: 295e8673271
Ref: library/operator operator __imul__8673306
Ref: 295f8673306
Ref: library/operator operator imatmul8673404
Ref: e698673404
Ref: library/operator operator __imatmul__8673442
Ref: 29608673442
Ref: library/operator operator ior8673574
Ref: 29618673574
Ref: library/operator operator __ior__8673608
Ref: 29628673608
Ref: library/operator operator ipow8673704
Ref: 29638673704
Ref: library/operator operator __ipow__8673739
Ref: 29648673739
Ref: library/operator operator irshift8673838
Ref: 29658673838
Ref: library/operator operator __irshift__8673876
Ref: 29668673876
Ref: library/operator operator isub8673981
Ref: 29678673981
Ref: library/operator operator __isub__8674016
Ref: 29688674016
Ref: library/operator operator itruediv8674114
Ref: 29698674114
Ref: library/operator operator __itruediv__8674153
Ref: 296a8674153
Ref: library/operator operator ixor8674259
Ref: 296b8674259
Ref: library/operator operator __ixor__8674294
Ref: 296c8674294
Node: File and Directory Access8674392
Ref: library/filesys doc8674545
Ref: 296d8674545
Ref: library/filesys file-and-directory-access8674545
Ref: 296e8674545
Ref: library/filesys filesys8674545
Ref: 296f8674545
Ref: library/filesys translation-repo8674545
Ref: 29708674545
Node: pathlib — Object-oriented filesystem paths8675382
Ref: library/pathlib doc8675538
Ref: 29718675538
Ref: library/pathlib module-pathlib8675538
Ref: a48675538
Ref: library/pathlib pathlib-object-oriented-filesystem-paths8675538
Ref: 29728675538
Ref: pathlib — Object-oriented filesystem paths-Footnote-18677745
Ref: pathlib — Object-oriented filesystem paths-Footnote-28677810
Node: Basic use8677852
Ref: library/pathlib basic-use8677964
Ref: 29768677964
Node: Exceptions<6>8678910
Ref: library/pathlib exceptions8679041
Ref: 29778679041
Ref: library/pathlib pathlib UnsupportedOperation8679082
Ref: 2278679082
Node: Pure paths8679296
Ref: library/pathlib id18679432
Ref: 29788679432
Ref: library/pathlib pure-paths8679432
Ref: 29738679432
Ref: library/pathlib pathlib PurePath8679647
Ref: 4a98679647
Ref: library/pathlib pathlib PurePosixPath8682011
Ref: 29798682011
Ref: library/pathlib pathlib PureWindowsPath8682315
Ref: 18148682315
Ref: Pure paths-Footnote-18683076
Node: General properties8683135
Ref: library/pathlib general-properties8683221
Ref: 297a8683221
Node: Operators<2>8684084
Ref: library/pathlib operators8684205
Ref: 297b8684205
Node: Accessing individual parts8685748
Ref: library/pathlib accessing-individual-parts8685873
Ref: 297c8685873
Ref: library/pathlib pathlib PurePath parts8686036
Ref: 297d8686036
Node: Methods and properties8686439
Ref: library/pathlib methods-and-properties8686543
Ref: 297e8686543
Ref: library/pathlib pathlib PurePath parser8686666
Ref: 22c8686666
Ref: library/pathlib pathlib PurePath drive8686875
Ref: 297f8686875
Ref: library/pathlib pathlib PurePath root8687298
Ref: 29808687298
Ref: library/pathlib pathlib PurePath anchor8688345
Ref: 29818688345
Ref: library/pathlib pathlib PurePath parents8688712
Ref: 8268688712
Ref: library/pathlib pathlib PurePath parent8689198
Ref: 183d8689198
Ref: library/pathlib pathlib PurePath name8690018
Ref: 29828690018
Ref: library/pathlib pathlib PurePath suffix8690411
Ref: 29838690411
Ref: library/pathlib pathlib PurePath suffixes8690771
Ref: 29848690771
Ref: library/pathlib pathlib PurePath stem8691109
Ref: 29858691109
Ref: library/pathlib pathlib PurePath as_posix8691408
Ref: 29868691408
Ref: library/pathlib pathlib PurePath is_absolute8691673
Ref: 183c8691673
Ref: library/pathlib pathlib PurePath is_relative_to8692265
Ref: 2c98692265
Ref: library/pathlib pathlib PurePath is_reserved8692980
Ref: 2a68692980
Ref: library/pathlib pathlib PurePath joinpath8693569
Ref: 29878693569
Ref: library/pathlib pathlib PurePath full_match8694156
Ref: 22b8694156
Ref: library/pathlib pathlib PurePath match8695071
Ref: 4af8695071
Ref: library/pathlib pathlib PurePath relative_to8695985
Ref: 2ca8695985
Ref: library/pathlib pathlib PurePath with_name8698194
Ref: 18078698194
Ref: library/pathlib pathlib PurePath with_stem8698908
Ref: 17708698908
Ref: library/pathlib pathlib PurePath with_suffix8699926
Ref: 17218699926
Ref: library/pathlib pathlib PurePath with_segments8700596
Ref: 4aa8700596
Ref: Methods and properties-Footnote-18701532
Node: Concrete paths8701624
Ref: library/pathlib concrete-paths8701763
Ref: 29748701763
Ref: library/pathlib id28701763
Ref: 29898701763
Ref: library/pathlib pathlib Path8702035
Ref: 2298702035
Ref: library/pathlib pathlib PosixPath8702417
Ref: 298a8702417
Ref: library/pathlib pathlib WindowsPath8702906
Ref: 29758702906
Node: Parsing and generating URIs8704432
Ref: library/pathlib parsing-and-generating-uris8704548
Ref: 298b8704548
Ref: library/pathlib pathlib Path from_uri8704839
Ref: 22a8704839
Ref: library/pathlib pathlib Path as_uri8705869
Ref: 298d8705869
Ref: Parsing and generating URIs-Footnote-18706425
Node: Expanding and resolving paths8706484
Ref: library/pathlib expanding-and-resolving-paths8706638
Ref: 298e8706638
Ref: library/pathlib pathlib Path home8706719
Ref: e768706719
Ref: library/pathlib pathlib Path expanduser8707089
Ref: e758707089
Ref: library/pathlib pathlib Path cwd8707494
Ref: 183b8707494
Ref: library/pathlib pathlib Path absolute8707716
Ref: 17bf8707716
Ref: library/pathlib pathlib Path resolve8708010
Ref: 180c8708010
Ref: library/pathlib pathlib Path readlink8709145
Ref: 9288709145
Node: Querying file type and status8709635
Ref: library/pathlib querying-file-type-and-status8709787
Ref: 298f8709787
Ref: library/pathlib pathlib Path stat8710232
Ref: 8298710232
Ref: library/pathlib pathlib Path lstat8710820
Ref: 29908710820
Ref: library/pathlib pathlib Path exists8711005
Ref: a238711005
Ref: library/pathlib pathlib Path is_file8711551
Ref: 22f8711551
Ref: library/pathlib pathlib Path is_dir8712060
Ref: 2308712060
Ref: library/pathlib pathlib Path is_symlink8712580
Ref: a258712580
Ref: library/pathlib pathlib Path is_junction8712829
Ref: 4ae8712829
Ref: library/pathlib pathlib Path is_mount8713042
Ref: a248713042
Ref: library/pathlib pathlib Path is_socket8713745
Ref: a298713745
Ref: library/pathlib pathlib Path is_fifo8714093
Ref: a288714093
Ref: library/pathlib pathlib Path is_block_device8714420
Ref: a268714420
Ref: library/pathlib pathlib Path is_char_device8714776
Ref: a278714776
Ref: library/pathlib pathlib Path samefile8715139
Ref: e738715139
Node: Reading and writing files8715692
Ref: library/pathlib reading-and-writing-files8715834
Ref: 29918715834
Ref: library/pathlib pathlib Path open8715907
Ref: 29928715907
Ref: library/pathlib pathlib Path read_text8716260
Ref: e788716260
Ref: library/pathlib pathlib Path read_bytes8716775
Ref: e7a8716775
Ref: library/pathlib pathlib Path write_text8717086
Ref: e778717086
Ref: library/pathlib pathlib Path write_bytes8717652
Ref: e798717652
Node: Reading directories8718035
Ref: library/pathlib reading-directories8718178
Ref: 29938718178
Ref: library/pathlib pathlib Path iterdir8718239
Ref: 173a8718239
Ref: library/pathlib pathlib Path glob8719094
Ref: 22d8719094
Ref: library/pathlib pathlib Path rglob8721133
Ref: 22e8721133
Ref: library/pathlib pathlib Path walk8721992
Ref: 4ab8721992
Node: Creating files and directories8726913
Ref: library/pathlib creating-files-and-directories8727052
Ref: 29958727052
Ref: library/pathlib pathlib Path touch8727135
Ref: 29968727135
Ref: library/pathlib pathlib Path mkdir8727716
Ref: e748727716
Ref: library/pathlib pathlib Path symlink_to8728778
Ref: 8288728778
Ref: library/pathlib pathlib Path hardlink_to8729866
Ref: 8278729866
Node: Renaming and deleting8730300
Ref: library/pathlib renaming-and-deleting8730445
Ref: 29978730445
Ref: library/pathlib pathlib Path rename8730510
Ref: 29988730510
Ref: library/pathlib pathlib Path replace8731531
Ref: 29998731531
Ref: library/pathlib pathlib Path unlink8732069
Ref: 1b828732069
Ref: library/pathlib pathlib Path rmdir8732564
Ref: 29948732564
Node: Permissions and ownership8732650
Ref: library/pathlib permissions-and-ownership8732756
Ref: 299a8732756
Ref: library/pathlib pathlib Path owner8732829
Ref: 2318732829
Ref: library/pathlib pathlib Path group8733445
Ref: 2328733445
Ref: library/pathlib pathlib Path chmod8734063
Ref: 82a8734063
Ref: library/pathlib pathlib Path lchmod8734658
Ref: 299b8734658
Node: Pattern language8734841
Ref: library/pathlib pathlib-pattern-language8734999
Ref: 29888734999
Ref: library/pathlib pattern-language8734999
Ref: 299c8734999
Node: Comparison to the glob module8737505
Ref: library/pathlib comparison-to-the-glob-module8737689
Ref: 299d8737689
Node: Comparison to the os and os path modules8739139
Ref: library/pathlib comparison-to-the-os-and-os-path-modules8739298
Ref: 299e8739298
Node: Corresponding tools8741485
Ref: library/pathlib corresponding-tools8741581
Ref: 299f8741581
Ref: Corresponding tools-Footnote-18746844
Ref: Corresponding tools-Footnote-28747158
Ref: Corresponding tools-Footnote-38747339
Ref: Corresponding tools-Footnote-48747569
Node: os path — Common pathname manipulations8747801
Ref: library/os path doc8748000
Ref: 29a38748000
Ref: library/os path module-os path8748000
Ref: a28748000
Ref: library/os path os-path-common-pathname-manipulations8748000
Ref: 29a48748000
Ref: library/os path translation-repo8748000
Ref: 29a58748000
Ref: library/os path os path abspath8750003
Ref: 13648750003
Ref: library/os path os path basename8750380
Ref: 29a18750380
Ref: library/os path os path commonpath8750887
Ref: e708750887
Ref: library/os path os path commonprefix8751452
Ref: e718751452
Ref: library/os path os path dirname8752240
Ref: 29a08752240
Ref: library/os path os path exists8752515
Ref: a1b8752515
Ref: library/os path os path lexists8753103
Ref: a1c8753103
Ref: library/os path os path expanduser8753395
Ref: a218753395
Ref: library/os path os path expandvars8754472
Ref: 14278754472
Ref: library/os path os path getatime8754964
Ref: 29a78754964
Ref: library/os path os path getmtime8755267
Ref: 29a88755267
Ref: library/os path os path getctime8755645
Ref: 29a98755645
Ref: library/os path os path getsize8756138
Ref: 29aa8756138
Ref: library/os path os path isabs8756371
Ref: 2248756371
Ref: library/os path os path isfile8756876
Ref: a1e8756876
Ref: library/os path os path isdir8757175
Ref: a1d8757175
Ref: library/os path os path isjunction8757473
Ref: 4a68757473
Ref: library/os path os path islink8757740
Ref: a198757740
Ref: library/os path os path ismount8758044
Ref: a1f8758044
Ref: library/os path os path isdevdrive8759062
Ref: 17568759062
Ref: library/os path os path isreserved8759898
Ref: 2238759898
Ref: library/os path os path join8760789
Ref: 173c8760789
Ref: library/os path os path normcase8762247
Ref: 29ab8762247
Ref: library/os path os path normpath8762589
Ref: 13638762589
Ref: library/os path os path realpath8763495
Ref: 2258763495
Ref: library/os path os path ALLOW_MISSING8765737
Ref: 42d8765737
Ref: library/os path os path relpath8765883
Ref: 4ad8765883
Ref: library/os path os path samefile8766409
Ref: faa8766409
Ref: library/os path os path sameopenfile8766926
Ref: 29ad8766926
Ref: library/os path os path samestat8767188
Ref: fa98767188
Ref: library/os path os path split8767627
Ref: 29a68767627
Ref: library/os path os path splitdrive8768439
Ref: c158768439
Ref: library/os path os path splitroot8769275
Ref: 4a78769275
Ref: library/os path os path splitext8770545
Ref: 29a28770545
Ref: library/os path os path supports_unicode_filenames8771510
Ref: 14dd8771510
Ref: os path — Common pathname manipulations-Footnote-18771718
Ref: os path — Common pathname manipulations-Footnote-28771789
Ref: os path — Common pathname manipulations-Footnote-38771858
Ref: os path — Common pathname manipulations-Footnote-48771924
Ref: os path — Common pathname manipulations-Footnote-58771979
Ref: os path — Common pathname manipulations-Footnote-68772071
Node: stat — Interpreting stat results8772163
Ref: library/stat doc8772360
Ref: 29ae8772360
Ref: library/stat module-stat8772360
Ref: d18772360
Ref: library/stat stat-interpreting-stat-results8772360
Ref: 29af8772360
Ref: library/stat translation-repo8772360
Ref: 29b08772360
Ref: library/stat stat S_ISDIR8773028
Ref: 29b18773028
Ref: library/stat stat S_ISCHR8773118
Ref: 29b28773118
Ref: library/stat stat S_ISBLK8773233
Ref: 29b38773233
Ref: library/stat stat S_ISREG8773339
Ref: 29b48773339
Ref: library/stat stat S_ISFIFO8773432
Ref: 29b58773432
Ref: library/stat stat S_ISLNK8773531
Ref: 29b68773531
Ref: library/stat stat S_ISSOCK8773625
Ref: 29b78773625
Ref: library/stat stat S_ISDOOR8773713
Ref: 1b568773713
Ref: library/stat stat S_ISPORT8773827
Ref: 1b578773827
Ref: library/stat stat S_ISWHT8773948
Ref: 1b588773948
Ref: library/stat stat S_IMODE8774155
Ref: 29b88774155
Ref: library/stat stat S_IFMT8774422
Ref: 29b98774422
Ref: library/stat stat filemode8775953
Ref: 118f8775953
Ref: library/stat stat ST_MODE8776366
Ref: ff38776366
Ref: library/stat stat ST_INO8776419
Ref: 29ba8776419
Ref: library/stat stat ST_DEV8776462
Ref: 29bb8776462
Ref: library/stat stat ST_NLINK8776516
Ref: 29bc8776516
Ref: library/stat stat ST_UID8776577
Ref: 29bd8776577
Ref: library/stat stat ST_GID8776628
Ref: 29be8776628
Ref: library/stat stat ST_SIZE8776680
Ref: 29bf8776680
Ref: library/stat stat ST_ATIME8776792
Ref: 29c08776792
Ref: library/stat stat ST_MTIME8776844
Ref: 29c18776844
Ref: library/stat stat ST_CTIME8776902
Ref: 29c28776902
Ref: library/stat stat S_IFSOCK8777944
Ref: 29c38777944
Ref: library/stat stat S_IFLNK8777983
Ref: 29c48777983
Ref: library/stat stat S_IFREG8778028
Ref: 29c58778028
Ref: library/stat stat S_IFBLK8778072
Ref: 29c68778072
Ref: library/stat stat S_IFDIR8778116
Ref: 29c78778116
Ref: library/stat stat S_IFCHR8778157
Ref: 29c88778157
Ref: library/stat stat S_IFIFO8778205
Ref: 29c98778205
Ref: library/stat stat S_IFDOOR8778241
Ref: ff48778241
Ref: library/stat stat S_IFPORT8778306
Ref: ff58778306
Ref: library/stat stat S_IFWHT8778377
Ref: ff68778377
Ref: library/stat stat S_ISUID8778697
Ref: 29ca8778697
Ref: library/stat stat S_ISGID8778740
Ref: 29cb8778740
Ref: library/stat stat S_ISVTX8779309
Ref: 29ce8779309
Ref: library/stat stat S_IRWXU8779558
Ref: 29cf8779558
Ref: library/stat stat S_IRUSR8779621
Ref: 29d08779621
Ref: library/stat stat S_IWUSR8779678
Ref: 29d18779678
Ref: library/stat stat S_IXUSR8779736
Ref: 29d28779736
Ref: library/stat stat S_IRWXG8779796
Ref: 29d38779796
Ref: library/stat stat S_IRGRP8779854
Ref: 29d48779854
Ref: library/stat stat S_IWGRP8779911
Ref: 29d58779911
Ref: library/stat stat S_IXGRP8779969
Ref: 29cc8779969
Ref: library/stat stat S_IRWXO8780029
Ref: 29d68780029
Ref: library/stat stat S_IROTH8780107
Ref: 29d78780107
Ref: library/stat stat S_IWOTH8780166
Ref: 29d88780166
Ref: library/stat stat S_IXOTH8780226
Ref: 29d98780226
Ref: library/stat stat S_ENFMT8780288
Ref: 29cd8780288
Ref: library/stat stat S_IREAD8780521
Ref: 29da8780521
Ref: library/stat stat S_IWRITE8780592
Ref: 29db8780592
Ref: library/stat stat S_IEXEC8780664
Ref: 29dc8780664
Ref: library/stat stat UF_SETTABLE8780822
Ref: 29dd8780822
Ref: library/stat stat UF_NODUMP8780910
Ref: 29de8780910
Ref: library/stat stat UF_IMMUTABLE8780964
Ref: 29df8780964
Ref: library/stat stat UF_APPEND8781028
Ref: 29e08781028
Ref: library/stat stat UF_OPAQUE8781094
Ref: 29e18781094
Ref: library/stat stat UF_NOUNLINK8781185
Ref: 29e28781185
Ref: library/stat stat UF_COMPRESSED8781259
Ref: 29e38781259
Ref: library/stat stat UF_TRACKED8781340
Ref: 29e48781340
Ref: library/stat stat UF_DATAVAULT8781441
Ref: 29e58781441
Ref: library/stat stat UF_HIDDEN8781573
Ref: 29e68781573
Ref: library/stat stat SF_SETTABLE8781662
Ref: 29e78781662
Ref: library/stat stat SF_SUPPORTED8781757
Ref: 29e88781757
Ref: library/stat stat SF_SYNTHETIC8781891
Ref: 29e98781891
Ref: library/stat stat SF_ARCHIVED8782035
Ref: 29ea8782035
Ref: library/stat stat SF_IMMUTABLE8782095
Ref: 29eb8782095
Ref: library/stat stat SF_APPEND8782159
Ref: 29ec8782159
Ref: library/stat stat SF_RESTRICTED8782225
Ref: 29ed8782225
Ref: library/stat stat SF_NOUNLINK8782347
Ref: 29ee8782347
Ref: library/stat stat SF_SNAPSHOT8782421
Ref: 29ef8782421
Ref: library/stat stat SF_FIRMLINK8782484
Ref: 29f08782484
Ref: library/stat stat SF_DATALESS8782585
Ref: 29f18782585
Ref: library/stat stat FILE_ATTRIBUTE_ARCHIVE8783029
Ref: 29f28783029
Ref: library/stat stat FILE_ATTRIBUTE_COMPRESSED8783067
Ref: 29f38783067
Ref: library/stat stat FILE_ATTRIBUTE_DEVICE8783108
Ref: 29f48783108
Ref: library/stat stat FILE_ATTRIBUTE_DIRECTORY8783145
Ref: 29f58783145
Ref: library/stat stat FILE_ATTRIBUTE_ENCRYPTED8783185
Ref: 29f68783185
Ref: library/stat stat FILE_ATTRIBUTE_HIDDEN8783225
Ref: 29f78783225
Ref: library/stat stat FILE_ATTRIBUTE_INTEGRITY_STREAM8783262
Ref: 29f88783262
Ref: library/stat stat FILE_ATTRIBUTE_NORMAL8783309
Ref: 29f98783309
Ref: library/stat stat FILE_ATTRIBUTE_NOT_CONTENT_INDEXED8783346
Ref: 29fa8783346
Ref: library/stat stat FILE_ATTRIBUTE_NO_SCRUB_DATA8783396
Ref: 29fb8783396
Ref: library/stat stat FILE_ATTRIBUTE_OFFLINE8783440
Ref: 29fc8783440
Ref: library/stat stat FILE_ATTRIBUTE_READONLY8783478
Ref: 29fd8783478
Ref: library/stat stat FILE_ATTRIBUTE_REPARSE_POINT8783517
Ref: 29fe8783517
Ref: library/stat stat FILE_ATTRIBUTE_SPARSE_FILE8783561
Ref: 29ff8783561
Ref: library/stat stat FILE_ATTRIBUTE_SYSTEM8783603
Ref: 2a008783603
Ref: library/stat stat FILE_ATTRIBUTE_TEMPORARY8783640
Ref: 2a018783640
Ref: library/stat stat FILE_ATTRIBUTE_VIRTUAL8783680
Ref: 2a028783680
Ref: library/stat stat IO_REPARSE_TAG_SYMLINK8783952
Ref: 2a038783952
Ref: library/stat stat IO_REPARSE_TAG_MOUNT_POINT8783990
Ref: 2a048783990
Ref: library/stat stat IO_REPARSE_TAG_APPEXECLINK8784032
Ref: 2a058784032
Ref: stat — Interpreting stat results-Footnote-18784139
Ref: stat — Interpreting stat results-Footnote-28784203
Ref: stat — Interpreting stat results-Footnote-38784250
Node: filecmp — File and Directory Comparisons8784330
Ref: library/filecmp doc8784539
Ref: 2a068784539
Ref: library/filecmp filecmp-file-and-directory-comparisons8784539
Ref: 2a078784539
Ref: library/filecmp module-filecmp8784539
Ref: 5a8784539
Ref: library/filecmp translation-repo8784539
Ref: 2a088784539
Ref: library/filecmp filecmp cmp8784998
Ref: 17718784998
Ref: library/filecmp filecmp cmpfiles8785791
Ref: 16f28785791
Ref: library/filecmp filecmp clear_cache8786736
Ref: f768786736
Ref: filecmp — File and Directory Comparisons-Footnote-18787053
Node: The dircmp class8787120
Ref: library/filecmp dircmp-objects8787215
Ref: 2a098787215
Ref: library/filecmp the-dircmp-class8787215
Ref: 2a0a8787215
Ref: library/filecmp filecmp dircmp8787276
Ref: f788787276
Ref: library/filecmp filecmp dircmp report8787935
Ref: 2a0b8787935
Ref: library/filecmp filecmp dircmp report_partial_closure8788052
Ref: 2a0c8788052
Ref: library/filecmp filecmp dircmp report_full_closure8788193
Ref: 2a0d8788193
Ref: library/filecmp filecmp dircmp left8788706
Ref: 2a0e8788706
Ref: library/filecmp filecmp dircmp right8788762
Ref: 2a0f8788762
Ref: library/filecmp filecmp dircmp left_list8788819
Ref: 2a108788819
Ref: library/filecmp filecmp dircmp right_list8788937
Ref: 2a118788937
Ref: library/filecmp filecmp dircmp common8789056
Ref: 2a128789056
Ref: library/filecmp filecmp dircmp left_only8789141
Ref: 2a138789141
Ref: library/filecmp filecmp dircmp right_only8789221
Ref: 2a148789221
Ref: library/filecmp filecmp dircmp common_dirs8789302
Ref: 2a158789302
Ref: library/filecmp filecmp dircmp common_files8789382
Ref: 2a168789382
Ref: library/filecmp filecmp dircmp common_funny8789454
Ref: 2a178789454
Ref: library/filecmp filecmp dircmp same_files8789657
Ref: 2a188789657
Ref: library/filecmp filecmp dircmp diff_files8789803
Ref: 2a198789803
Ref: library/filecmp filecmp dircmp funny_files8789968
Ref: 2a1a8789968
Ref: library/filecmp filecmp dircmp subdirs8790086
Ref: 1a8c8790086
Ref: library/filecmp filecmp DEFAULT_IGNORES8790511
Ref: f778790511
Node: tempfile — Generate temporary files and directories8791192
Ref: library/tempfile doc8791413
Ref: 2a1b8791413
Ref: library/tempfile module-tempfile8791413
Ref: e08791413
Ref: library/tempfile tempfile-generate-temporary-files-and-directories8791413
Ref: 2a1c8791413
Ref: library/tempfile translation-repo8791413
Ref: 2a1d8791413
Ref: library/tempfile tempfile TemporaryFile8792579
Ref: 2a1e8792579
Ref: library/tempfile tempfile NamedTemporaryFile8794754
Ref: 4c98794754
Ref: library/tempfile tempfile SpooledTemporaryFile8798554
Ref: 6968798554
Ref: library/tempfile tempfile SpooledTemporaryFile rollover8799070
Ref: 2a218799070
Ref: library/tempfile tempfile TemporaryDirectory8800032
Ref: 127a8800032
Ref: library/tempfile tempfile TemporaryDirectory name8800559
Ref: 2a228800559
Ref: library/tempfile tempfile TemporaryDirectory cleanup8800914
Ref: 2a238800914
Ref: library/tempfile tempfile mkstemp8802176
Ref: 2a1f8802176
Ref: library/tempfile tempfile mkdtemp8805049
Ref: 21f8805049
Ref: library/tempfile tempfile gettempdir8806261
Ref: 1a398806261
Ref: library/tempfile tempfile gettempdirb8807445
Ref: 1a3a8807445
Ref: library/tempfile tempfile gettempprefix8807586
Ref: 2a258807586
Ref: library/tempfile tempfile gettempprefixb8807745
Ref: 2a268807745
Ref: library/tempfile tempfile tempdir8808324
Ref: 1a388808324
Ref: tempfile — Generate temporary files and directories-Footnote-18809439
Node: Examples<5>8809507
Ref: library/tempfile examples8809651
Ref: 2a278809651
Ref: library/tempfile tempfile-examples8809651
Ref: 2a208809651
Node: Deprecated functions and variables8811041
Ref: library/tempfile deprecated-functions-and-variables8811185
Ref: 2a288811185
Ref: library/tempfile tempfile-mktemp-deprecated8811185
Ref: 2a298811185
Ref: library/tempfile tempfile mktemp8811808
Ref: 19d68811808
Node: glob — Unix style pathname pattern expansion8812934
Ref: library/glob doc8813155
Ref: 2a2a8813155
Ref: library/glob glob-unix-style-pathname-pattern-expansion8813155
Ref: 2a2b8813155
Ref: library/glob module-glob8813155
Ref: 648813155
Ref: library/glob translation-repo8813155
Ref: 2a2c8813155
Ref: library/glob glob glob8814316
Ref: 29f8814316
Ref: library/glob glob iglob8816645
Ref: 80d8816645
Ref: library/glob glob escape8817557
Ref: f7e8817557
Ref: library/glob glob translate8817980
Ref: 1ea8817980
Ref: glob — Unix style pathname pattern expansion-Footnote-18819543
Node: Examples<6>8819607
Ref: library/glob examples8819701
Ref: 2a2d8819701
Node: fnmatch — Unix filename pattern matching8820810
Ref: library/fnmatch doc8821019
Ref: 2a2e8821019
Ref: library/fnmatch fnmatch-unix-filename-pattern-matching8821019
Ref: 2a2f8821019
Ref: library/fnmatch module-fnmatch8821019
Ref: 5c8821019
Ref: library/fnmatch translation-repo8821019
Ref: 2a308821019
Ref: library/fnmatch fnmatch fnmatch8822868
Ref: 19fa8822868
Ref: library/fnmatch fnmatch fnmatchcase8823545
Ref: 19fb8823545
Ref: library/fnmatch fnmatch filter8823803
Ref: 19fc8823803
Ref: library/fnmatch fnmatch translate8824095
Ref: 1bd68824095
Ref: fnmatch — Unix filename pattern matching-Footnote-18824730
Node: linecache — Random access to text lines8824797
Ref: library/linecache doc8824997
Ref: 2a318824997
Ref: library/linecache linecache-random-access-to-text-lines8824997
Ref: 2a328824997
Ref: library/linecache module-linecache8824997
Ref: 858824997
Ref: library/linecache translation-repo8824997
Ref: 2a338824997
Ref: library/linecache linecache getline8825816
Ref: e568825816
Ref: library/linecache linecache clearcache8826585
Ref: 2a368826585
Ref: library/linecache linecache checkcache8826754
Ref: 16898826754
Ref: library/linecache linecache lazycache8827032
Ref: e558827032
Ref: linecache — Random access to text lines-Footnote-18827581
Ref: linecache — Random access to text lines-Footnote-28827650
Node: shutil — High-level file operations8827692
Ref: library/shutil doc8827841
Ref: 2a378827841
Ref: library/shutil module-shutil8827841
Ref: c58827841
Ref: library/shutil shutil-high-level-file-operations8827841
Ref: 2a388827841
Ref: library/shutil translation-repo8827841
Ref: 2a398827841
Ref: shutil — High-level file operations-Footnote-18828937
Node: Directory and files operations8829003
Ref: library/shutil directory-and-files-operations8829136
Ref: 2a3a8829136
Ref: library/shutil file-operations8829136
Ref: 2a3b8829136
Ref: library/shutil shutil copyfileobj8829217
Ref: a6b8829217
Ref: library/shutil shutil copyfile8829814
Ref: a678829814
Ref: library/shutil shutil SpecialFileError8831428
Ref: 13658831428
Ref: library/shutil shutil SameFileError8831616
Ref: fd78831616
Ref: library/shutil shutil copymode8831788
Ref: 17bc8831788
Ref: library/shutil shutil copystat8832682
Ref: 11728832682
Ref: library/shutil shutil copy8834758
Ref: a688834758
Ref: library/shutil shutil copy28836265
Ref: a698836265
Ref: library/shutil shutil ignore_patterns8837739
Ref: 2a3c8837739
Ref: library/shutil shutil copytree8838039
Ref: a368838039
Ref: library/shutil shutil rmtree8841503
Ref: 3018841503
Ref: library/shutil shutil rmtree avoids_symlink_attacks8844268
Ref: 2a3d8844268
Ref: library/shutil shutil move8844604
Ref: a6a8844604
Ref: library/shutil shutil disk_usage8846649
Ref: 11718846649
Ref: library/shutil shutil chown8847348
Ref: 2408847348
Ref: library/shutil shutil which8847971
Ref: 4b78847971
Ref: library/shutil shutil Error8850573
Ref: fd68850573
Node: Platform-dependent efficient copy operations8850909
Ref: library/shutil platform-dependent-efficient-copy-operations8851045
Ref: 2a3f8851045
Ref: library/shutil shutil-platform-dependent-efficient-copy-operations8851045
Ref: a6c8851045
Ref: Platform-dependent efficient copy operations-Footnote-18852162
Ref: Platform-dependent efficient copy operations-Footnote-28852227
Node: copytree example8852275
Ref: library/shutil copytree-example8852434
Ref: 2a408852434
Ref: library/shutil shutil-copytree-example8852434
Ref: 2a418852434
Node: rmtree example8853094
Ref: library/shutil rmtree-example8853200
Ref: 2a428853200
Ref: library/shutil shutil-rmtree-example8853200
Ref: 2a3e8853200
Node: Archiving operations8853741
Ref: library/shutil archiving-operations8853923
Ref: 125e8853923
Ref: library/shutil id18853923
Ref: 2a438853923
Ref: library/shutil shutil make_archive8854230
Ref: 4b68854230
Ref: library/shutil shutil get_archive_formats8856656
Ref: 2a468856656
Ref: library/shutil shutil register_archive_format8857493
Ref: 2a458857493
Ref: library/shutil shutil unregister_archive_format8858794
Ref: 2a478858794
Ref: library/shutil shutil unpack_archive8858929
Ref: 46e8858929
Ref: library/shutil shutil register_unpack_format8860710
Ref: 2a488860710
Ref: library/shutil shutil unregister_unpack_format8861629
Ref: 2a4a8861629
Ref: library/shutil shutil get_unpack_formats8861753
Ref: 2a498861753
Ref: Archiving operations-Footnote-18862701
Node: Archiving example8862743
Ref: library/shutil archiving-example8862857
Ref: 2a4b8862857
Ref: library/shutil shutil-archiving-example8862857
Ref: 2a4c8862857
Node: Archiving example with base_dir8863948
Ref: library/shutil archiving-example-with-base-dir8864062
Ref: 2a4d8864062
Ref: library/shutil shutil-archiving-example-with-basedir8864062
Ref: 2a448864062
Node: Querying the size of the output terminal8865163
Ref: library/shutil querying-the-size-of-the-output-terminal8865306
Ref: 2a4e8865306
Ref: library/shutil shutil get_terminal_size8865407
Ref: 11478865407
Ref: Querying the size of the output terminal-Footnote-18867069
Node: Data Persistence8867152
Ref: library/persistence doc8867305
Ref: 2a518867305
Ref: library/persistence data-persistence8867305
Ref: 2a528867305
Ref: library/persistence persistence8867305
Ref: 2a538867305
Ref: library/persistence translation-repo8867305
Ref: 2a548867305
Node: pickle — Python object serialization8868136
Ref: library/pickle doc8868281
Ref: 2a558868281
Ref: library/pickle module-pickle8868281
Ref: a68868281
Ref: library/pickle pickle-python-object-serialization8868281
Ref: 2a568868281
Ref: pickle — Python object serialization-Footnote-18870111
Ref: pickle — Python object serialization-Footnote-28870177
Node: Relationship to other Python modules8870241
Ref: library/pickle relationship-to-other-python-modules8870379
Ref: 2a588870379
Node: Comparison with marshal8870535
Ref: library/pickle comparison-with-marshal8870660
Ref: 2a598870660
Node: Comparison with json8871999
Ref: library/pickle comparison-with-json8872124
Ref: 2a578872124
Ref: library/pickle id28872124
Ref: 2a5a8872124
Ref: Comparison with json-Footnote-18873289
Node: Data stream format8873314
Ref: library/pickle data-stream-format8873477
Ref: 2a5c8873477
Ref: library/pickle pickle-protocols8873477
Ref: ce78873477
Ref: Data stream format-Footnote-18876406
Ref: Data stream format-Footnote-28876448
Ref: Data stream format-Footnote-38876490
Node: Module Interface8876532
Ref: library/pickle module-interface8876693
Ref: 2a5f8876693
Ref: library/pickle pickle HIGHEST_PROTOCOL8877141
Ref: 14f48877141
Ref: library/pickle pickle DEFAULT_PROTOCOL8877414
Ref: 8348877414
Ref: library/pickle pickle dump8877917
Ref: 2a608877917
Ref: library/pickle pickle dumps8878416
Ref: 14f38878416
Ref: library/pickle pickle load8878853
Ref: d388878853
Ref: library/pickle pickle loads8879602
Ref: d398879602
Ref: library/pickle pickle PickleError8880325
Ref: 2a618880325
Ref: library/pickle pickle PicklingError8880464
Ref: 2a628880464
Ref: library/pickle pickle UnpicklingError8880748
Ref: 2a648880748
Ref: library/pickle pickle Pickler8881257
Ref: a2b8881257
Ref: library/pickle pickle Pickler dump8882835
Ref: 1bd58882835
Ref: library/pickle pickle Pickler persistent_id8882977
Ref: 16a58882977
Ref: library/pickle pickle Pickler dispatch_table8883767
Ref: 11668883767
Ref: library/pickle pickle Pickler reducer_override8884906
Ref: a2c8884906
Ref: library/pickle pickle Pickler fast8885511
Ref: 2a6a8885511
Ref: library/pickle pickle Unpickler8885980
Ref: 15c48885980
Ref: library/pickle pickle Unpickler load8888103
Ref: 2a6c8888103
Ref: library/pickle pickle Unpickler persistent_load8888398
Ref: 16ac8888398
Ref: library/pickle pickle Unpickler find_class8888974
Ref: 2a6d8888974
Ref: library/pickle pickle PickleBuffer8889647
Ref: 15c68889647
Ref: library/pickle pickle PickleBuffer raw8890252
Ref: 2a6f8890252
Ref: library/pickle pickle PickleBuffer release8890595
Ref: 2a708890595
Node: What can be pickled and unpickled?8890711
Ref: library/pickle pickle-picklable8890878
Ref: 2a638890878
Ref: library/pickle what-can-be-pickled-and-unpickled8890878
Ref: 2a718890878
Ref: What can be pickled and unpickled?-Footnote-18893629
Ref: What can be pickled and unpickled?-Footnote-28893762
Node: Pickling Class Instances8893898
Ref: library/pickle pickle-inst8894103
Ref: 2a5b8894103
Ref: library/pickle pickling-class-instances8894103
Ref: 2a728894103
Ref: library/pickle object __getnewargs_ex__8895038
Ref: 2a738895038
Ref: library/pickle object __getnewargs__8895849
Ref: e048895849
Ref: library/pickle object __getstate__8896403
Ref: 5db8896403
Ref: library/pickle object __setstate__8897740
Ref: 9df8897740
Ref: library/pickle object __reduce__8899589
Ref: 9de8899589
Ref: library/pickle object __reduce_ex__8902470
Ref: 16bf8902470
Ref: Pickling Class Instances-Footnote-18903118
Node: Persistence of External Objects8903213
Ref: library/pickle persistence-of-external-objects8903329
Ref: 2a758903329
Ref: library/pickle pickle-persistent8903329
Ref: 2a668903329
Ref: Persistence of External Objects-Footnote-18907986
Node: Dispatch Tables8908250
Ref: library/pickle dispatch-tables8908400
Ref: 2a768908400
Ref: library/pickle pickle-dispatch8908400
Ref: 2a688908400
Node: Handling Stateful Objects8909688
Ref: library/pickle handling-stateful-objects8909798
Ref: 2a778909798
Ref: library/pickle pickle-state8909798
Ref: 2a748909798
Node: Custom Reduction for Types Functions and Other Objects8912080
Ref: library/pickle custom-reduction-for-types-functions-and-other-objects8912270
Ref: 2a788912270
Ref: library/pickle reducer-override8912270
Ref: 2a698912270
Node: Out-of-band Buffers8914366
Ref: library/pickle out-of-band-buffers8914551
Ref: 2a798914551
Ref: library/pickle pickle-oob8914551
Ref: 2a658914551
Node: Provider API8915390
Ref: library/pickle provider-api8915479
Ref: 2a7a8915479
Node: Consumer API8916076
Ref: library/pickle consumer-api8916184
Ref: 2a7b8916184
Node: Example<4>8917487
Ref: library/pickle example8917574
Ref: 2a7c8917574
Ref: Example<4>-Footnote-18919952
Node: Restricting Globals8919994
Ref: library/pickle pickle-restrict8920139
Ref: 2a6e8920139
Ref: library/pickle restricting-globals8920139
Ref: 2a7d8920139
Node: Performance<2>8922908
Ref: library/pickle performance8923045
Ref: 2a7e8923045
Node: Examples<7>8923316
Ref: library/pickle examples8923425
Ref: 2a7f8923425
Ref: library/pickle pickle-example8923425
Ref: 2a808923425
Node: copyreg — Register pickle support functions8924636
Ref: library/copyreg doc8924826
Ref: 2a818924826
Ref: library/copyreg copyreg-register-pickle-support-functions8924826
Ref: 2a828924826
Ref: library/copyreg module-copyreg8924826
Ref: 268924826
Ref: library/copyreg translation-repo8924826
Ref: 2a838924826
Ref: library/copyreg copyreg constructor8925414
Ref: 2a848925414
Ref: library/copyreg copyreg pickle8925617
Ref: 2a678925617
Ref: copyreg — Register pickle support functions-Footnote-18926357
Node: Example<5>8926424
Ref: library/copyreg example8926516
Ref: 2a858926516
Node: shelve — Python object persistence8927060
Ref: library/shelve doc8927260
Ref: 2a868927260
Ref: library/shelve module-shelve8927260
Ref: c38927260
Ref: library/shelve shelve-python-object-persistence8927260
Ref: 2a878927260
Ref: library/shelve translation-repo8927260
Ref: 2a888927260
Ref: library/shelve shelve open8927845
Ref: 18108927845
Ref: library/shelve shelve-security8929887
Ref: 2a8c8929887
Ref: library/shelve shelve Shelf sync8930380
Ref: 2a8a8930380
Ref: library/shelve shelve Shelf close8930701
Ref: 2a8b8930701
Ref: shelve — Python object persistence-Footnote-18931083
Ref: shelve — Python object persistence-Footnote-28931149
Node: Restrictions8931254
Ref: library/shelve restrictions8931358
Ref: 2a8d8931358
Ref: library/shelve shelve Shelf8932538
Ref: fd48932538
Ref: library/shelve shelve BsdDbShelf8933929
Ref: 24108933929
Ref: library/shelve shelve DbfilenameShelf8934645
Ref: 24118934645
Ref: Restrictions-Footnote-18935254
Node: Example<6>8935307
Ref: library/shelve example8935411
Ref: 2a8e8935411
Ref: library/shelve shelve-example8935411
Ref: 2a898935411
Node: marshal — Internal Python object serialization8937086
Ref: library/marshal doc8937283
Ref: 2a8f8937283
Ref: library/marshal marshal-internal-python-object-serialization8937283
Ref: 2a908937283
Ref: library/marshal module-marshal8937283
Ref: 8d8937283
Ref: library/marshal translation-repo8937283
Ref: 2a918937283
Ref: library/marshal marshal dump8939904
Ref: 2a928939904
Ref: library/marshal marshal load8940743
Ref: 1ba48940743
Ref: library/marshal marshal dumps8941739
Ref: ed98941739
Ref: library/marshal marshal loads8942430
Ref: 2a938942430
Ref: library/marshal marshal version8943197
Ref: 2a948943197
Ref: marshal — Internal Python object serialization-Footnote-18943551
Node: dbm — Interfaces to Unix “databases”8943931
Ref: library/dbm doc8944145
Ref: 2a958944145
Ref: library/dbm dbm-interfaces-to-unix-databases8944145
Ref: 2a968944145
Ref: library/dbm module-dbm8944145
Ref: 318944145
Ref: library/dbm translation-repo8944145
Ref: 2a978944145
Ref: library/dbm dbm error8944686
Ref: 2a988944686
Ref: library/dbm dbm whichdb8944951
Ref: 2a998944951
Ref: library/dbm dbm open8945654
Ref: f618945654
Ref: dbm — Interfaces to Unix “databases”-Footnote-18949507
Ref: dbm — Interfaces to Unix “databases”-Footnote-28949579
Node: dbm sqlite3 — SQLite backend for dbm8949632
Ref: library/dbm dbm-sqlite3-sqlite-backend-for-dbm8949790
Ref: 2a9a8949790
Ref: library/dbm module-dbm sqlite38949790
Ref: 358949790
Ref: library/dbm dbm sqlite3 open8950438
Ref: 2a9b8950438
Ref: library/dbm dbm sqlite3 sqlite3 close8951570
Ref: 2a9c8951570
Ref: dbm sqlite3 — SQLite backend for dbm-Footnote-18951679
Node: dbm gnu — GNU database manager8951750
Ref: library/dbm dbm-gnu-gnu-database-manager8951950
Ref: 2a9d8951950
Ref: library/dbm module-dbm gnu8951950
Ref: 338951950
Ref: library/dbm dbm gnu error8952653
Ref: aaf8952653
Ref: library/dbm dbm gnu open_flags8952853
Ref: 2a9e8952853
Ref: library/dbm dbm gnu open8952971
Ref: 1bcf8952971
Ref: library/dbm dbm gnu gdbm close8955139
Ref: 2a9f8955139
Ref: library/dbm dbm gnu gdbm firstkey8955207
Ref: 2aa08955207
Ref: library/dbm dbm gnu gdbm nextkey8955545
Ref: 2aa18955545
Ref: library/dbm dbm gnu gdbm reorganize8955930
Ref: 2aa28955930
Ref: library/dbm dbm gnu gdbm sync8956367
Ref: 2aa38956367
Ref: dbm gnu — GNU database manager-Footnote-18956568
Node: dbm ndbm — New Database Manager8956635
Ref: library/dbm dbm-ndbm-new-database-manager8956837
Ref: 2aa48956837
Ref: library/dbm module-dbm ndbm8956837
Ref: 348956837
Ref: library/dbm dbm ndbm error8957857
Ref: ab08957857
Ref: library/dbm dbm ndbm library8958059
Ref: 2aa58958059
Ref: library/dbm dbm ndbm open8958139
Ref: 1bd08958139
Ref: library/dbm dbm ndbm ndbm close8959711
Ref: 2aa68959711
Ref: dbm ndbm — New Database Manager-Footnote-18959815
Node: dbm dumb — Portable DBM implementation8959883
Ref: library/dbm dbm-dumb-portable-dbm-implementation8960044
Ref: 2aa78960044
Ref: library/dbm module-dbm dumb8960044
Ref: 328960044
Ref: library/dbm dbm dumb error8960792
Ref: aae8960792
Ref: library/dbm dbm dumb open8960994
Ref: aab8960994
Ref: library/dbm dbm dumb dumbdbm close8962867
Ref: 2aa88962867
Ref: library/dbm dbm dumb dumbdbm sync8962933
Ref: 2aa98962933
Ref: dbm dumb — Portable DBM implementation-Footnote-18963145
Node: sqlite3 — DB-API 2 0 interface for SQLite databases8963213
Ref: library/sqlite3 doc8963370
Ref: 2aaa8963370
Ref: library/sqlite3 module-sqlite38963370
Ref: cf8963370
Ref: library/sqlite3 sqlite3-db-api-2-0-interface-for-sqlite-databases8963370
Ref: 2aab8963370
Ref: library/sqlite3 translation-repo8963370
Ref: 2aac8963370
Ref: library/sqlite3 sqlite3-intro8963531
Ref: 2aad8963531
Ref: sqlite3 — DB-API 2 0 interface for SQLite databases-Footnote-18964976
Ref: sqlite3 — DB-API 2 0 interface for SQLite databases-Footnote-28965041
Ref: sqlite3 — DB-API 2 0 interface for SQLite databases-Footnote-38965083
Node: Tutorial8965125
Ref: library/sqlite3 sqlite3-tutorial8965241
Ref: 2aae8965241
Ref: library/sqlite3 tutorial8965241
Ref: 2ab28965241
Ref: Tutorial-Footnote-18971204
Ref: Tutorial-Footnote-28971261
Ref: Tutorial-Footnote-38971320
Ref: Tutorial-Footnote-48971369
Ref: Tutorial-Footnote-58971415
Node: Reference8971467
Ref: library/sqlite3 reference8971605
Ref: 2abc8971605
Ref: library/sqlite3 sqlite3-reference8971605
Ref: 2aaf8971605
Ref: library/sqlite3 sqlite3-module-contents8971644
Ref: 2abd8971644
Node: Module functions8971975
Ref: library/sqlite3 module-functions8972062
Ref: 2abe8972062
Ref: library/sqlite3 sqlite3-module-functions8972062
Ref: 2abf8972062
Ref: library/sqlite3 sqlite3 connect8972115
Ref: 2a88972115
Ref: library/sqlite3 sqlite3 complete_statement8976843
Ref: 2ac88976843
Ref: library/sqlite3 sqlite3 enable_callback_tracebacks8977660
Ref: 2ac98977660
Ref: library/sqlite3 sqlite3 register_adapter8978324
Ref: 2aca8978324
Ref: library/sqlite3 sqlite3 register_converter8978662
Ref: 2ac18978662
Ref: Module functions-Footnote-18979311
Ref: Module functions-Footnote-28979354
Ref: Module functions-Footnote-38979396
Node: Module constants8979473
Ref: library/sqlite3 module-constants8979587
Ref: 2acc8979587
Ref: library/sqlite3 sqlite3-module-constants8979587
Ref: 2acd8979587
Ref: library/sqlite3 sqlite3 LEGACY_TRANSACTION_CONTROL8979640
Ref: 2ac68979640
Ref: library/sqlite3 sqlite3 PARSE_DECLTYPES8979914
Ref: 2ac28979914
Ref: library/sqlite3 sqlite3 PARSE_COLNAMES8980895
Ref: 2ac38980895
Ref: library/sqlite3 sqlite3 SQLITE_OK8981490
Ref: 2ace8981490
Ref: library/sqlite3 sqlite3 SQLITE_DENY8981518
Ref: 2acf8981518
Ref: library/sqlite3 sqlite3 SQLITE_IGNORE8981548
Ref: 2ad08981548
Ref: library/sqlite3 sqlite3 apilevel8981982
Ref: 2ad18981982
Ref: library/sqlite3 sqlite3 paramstyle8982125
Ref: 2ad28982125
Ref: library/sqlite3 sqlite3 sqlite_version8982402
Ref: 2ad38982402
Ref: library/sqlite3 sqlite3 sqlite_version_info8982516
Ref: 2ad48982516
Ref: library/sqlite3 sqlite3 threadsafety8982658
Ref: 67f8982658
Ref: library/sqlite3 sqlite3 version8984989
Ref: 2cf8984989
Ref: library/sqlite3 sqlite3 version_info8985415
Ref: 2d08985415
Ref: library/sqlite3 sqlite3-dbconfig-constants8985869
Ref: 2ad58985869
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_DEFENSIVE8985869
Ref: 2ad68985869
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_DQS_DDL8985913
Ref: 2ad78985913
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_DQS_DML8985955
Ref: 2ad88985955
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_FKEY8985997
Ref: 2ad98985997
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER8986043
Ref: 2ada8986043
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION8986099
Ref: 2adb8986099
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_QPSG8986155
Ref: 2adc8986155
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_TRIGGER8986201
Ref: 2add8986201
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_ENABLE_VIEW8986250
Ref: 2ade8986250
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_LEGACY_ALTER_TABLE8986296
Ref: 2adf8986296
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_LEGACY_FILE_FORMAT8986349
Ref: 2ae08986349
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE8986402
Ref: 2ae18986402
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_RESET_DATABASE8986453
Ref: 2ae28986453
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_TRIGGER_EQP8986502
Ref: 2ae38986502
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_TRUSTED_SCHEMA8986548
Ref: 2ae48986548
Ref: library/sqlite3 sqlite3 SQLITE_DBCONFIG_WRITABLE_SCHEMA8986597
Ref: 2ae58986597
Ref: Module constants-Footnote-18987106
Ref: Module constants-Footnote-28987149
Ref: Module constants-Footnote-38987204
Node: Connection objects8987255
Ref: library/sqlite3 connection-objects8987367
Ref: 2ae68987367
Ref: library/sqlite3 sqlite3-connection-objects8987367
Ref: 2ae78987367
Ref: library/sqlite3 sqlite3 Connection8987424
Ref: 2458987424
Ref: library/sqlite3 sqlite3 Connection cursor8988103
Ref: 2ab38988103
Ref: library/sqlite3 sqlite3 Connection blobopen8988408
Ref: 6848988408
Ref: library/sqlite3 sqlite3 Connection commit8989677
Ref: 2ab78989677
Ref: library/sqlite3 sqlite3 Connection rollback8990036
Ref: 2ae98990036
Ref: library/sqlite3 sqlite3 Connection close8990402
Ref: 2468990402
Ref: library/sqlite3 sqlite3 Connection execute8990821
Ref: 2aea8990821
Ref: library/sqlite3 sqlite3 Connection executemany8991048
Ref: 2aeb8991048
Ref: library/sqlite3 sqlite3 Connection executescript8991281
Ref: 2aec8991281
Ref: library/sqlite3 sqlite3 Connection create_function8991503
Ref: 2a98991503
Ref: library/sqlite3 sqlite3 Connection create_aggregate8993185
Ref: 2aa8993185
Ref: library/sqlite3 sqlite3 Connection create_window_function8995123
Ref: 6838995123
Ref: library/sqlite3 sqlite3 Connection create_collation8998327
Ref: 6798998327
Ref: library/sqlite3 sqlite3 Connection interrupt8999759
Ref: 2af08999759
Ref: library/sqlite3 sqlite3 Connection set_authorizer8999987
Ref: 2ab8999987
Ref: library/sqlite3 sqlite3 Connection set_progress_handler9001627
Ref: 2ac9001627
Ref: library/sqlite3 sqlite3 Connection set_trace_callback9002477
Ref: 2ad9002477
Ref: library/sqlite3 sqlite3 Connection enable_load_extension9003778
Ref: 8449003778
Ref: library/sqlite3 sqlite3 Connection load_extension9006118
Ref: 4bb9006118
Ref: library/sqlite3 sqlite3 Connection iterdump9007095
Ref: 2479007095
Ref: library/sqlite3 sqlite3 Connection backup9008115
Ref: b989008115
Ref: library/sqlite3 sqlite3 Connection getlimit9010487
Ref: 67e9010487
Ref: library/sqlite3 sqlite3 Connection setlimit9011117
Ref: 67d9011117
Ref: library/sqlite3 sqlite3 Connection getconfig9012209
Ref: 4bc9012209
Ref: library/sqlite3 sqlite3 Connection setconfig9012482
Ref: 4bd9012482
Ref: library/sqlite3 sqlite3 Connection serialize9012933
Ref: 6819012933
Ref: library/sqlite3 sqlite3 Connection deserialize9013687
Ref: 6829013687
Ref: library/sqlite3 sqlite3 Connection autocommit9014849
Ref: 4b99014849
Ref: library/sqlite3 sqlite3 Connection in_transaction9016278
Ref: 2af39016278
Ref: library/sqlite3 sqlite3 Connection isolation_level9016564
Ref: 2ac49016564
Ref: library/sqlite3 sqlite3 Connection row_factory9017497
Ref: 17379017497
Ref: library/sqlite3 sqlite3 Connection text_factory9017993
Ref: 2af59017993
Ref: library/sqlite3 sqlite3 Connection total_changes9018399
Ref: 2af69018399
Ref: Connection objects-Footnote-19018630
Ref: Connection objects-Footnote-29018676
Ref: Connection objects-Footnote-39018741
Ref: Connection objects-Footnote-49018800
Ref: Connection objects-Footnote-59018859
Ref: Connection objects-Footnote-69018901
Ref: Connection objects-Footnote-79018943
Ref: Connection objects-Footnote-89019035
Ref: Connection objects-Footnote-99019077
Ref: Connection objects-Footnote-109019169
Node: Cursor objects9019270
Ref: library/sqlite3 cursor-objects9019377
Ref: 2af79019377
Ref: library/sqlite3 sqlite3-cursor-objects9019377
Ref: 2af89019377
Ref: library/sqlite3 sqlite3 Cursor9019987
Ref: 2ab49019987
Ref: library/sqlite3 sqlite3 Cursor execute9020086
Ref: 2d19020086
Ref: library/sqlite3 sqlite3 Cursor executemany9021584
Ref: 2d29021584
Ref: library/sqlite3 sqlite3 Cursor executescript9023087
Ref: 2aed9023087
Ref: library/sqlite3 sqlite3 Cursor fetchone9023933
Ref: 2ab59023933
Ref: library/sqlite3 sqlite3 Cursor fetchmany9024213
Ref: 16119024213
Ref: library/sqlite3 sqlite3 Cursor fetchall9025163
Ref: 2ab89025163
Ref: library/sqlite3 sqlite3 Cursor close9025444
Ref: 2af99025444
Ref: library/sqlite3 sqlite3 Cursor setinputsizes9025748
Ref: 2afa9025748
Ref: library/sqlite3 sqlite3 Cursor setoutputsize9025857
Ref: 2afb9025857
Ref: library/sqlite3 sqlite3 Cursor arraysize9025978
Ref: 16129025978
Ref: library/sqlite3 sqlite3 Cursor connection9026318
Ref: 2afc9026318
Ref: library/sqlite3 sqlite3 Cursor description9026813
Ref: 16689026813
Ref: library/sqlite3 sqlite3 Cursor lastrowid9027189
Ref: cf79027189
Ref: library/sqlite3 sqlite3 Cursor rowcount9027882
Ref: 19069027882
Ref: library/sqlite3 sqlite3 Cursor row_factory9028440
Ref: 2af49028440
Ref: library/sqlite3 sqlite3-columns-by-name9029211
Ref: 2afd9029211
Ref: Cursor objects-Footnote-19029247
Ref: Cursor objects-Footnote-29029304
Node: Row objects9029355
Ref: library/sqlite3 row-objects9029456
Ref: 2afe9029456
Ref: library/sqlite3 sqlite3-row-objects9029456
Ref: 2aff9029456
Ref: library/sqlite3 sqlite3 Row9029499
Ref: ea59029499
Ref: library/sqlite3 sqlite3 Row keys9029950
Ref: 2b009029950
Node: Blob objects9030228
Ref: library/sqlite3 blob-objects9030338
Ref: 2b019030338
Ref: library/sqlite3 sqlite3-blob-objects9030338
Ref: 2b029030338
Ref: library/sqlite3 sqlite3 Blob9030383
Ref: 6859030383
Ref: library/sqlite3 sqlite3 Blob close9031541
Ref: 2b039031541
Ref: library/sqlite3 sqlite3 Blob read9031791
Ref: 2b049031791
Ref: library/sqlite3 sqlite3 Blob write9032140
Ref: 2b059032140
Ref: library/sqlite3 sqlite3 Blob tell9032369
Ref: 2b069032369
Ref: library/sqlite3 sqlite3 Blob seek9032454
Ref: 2b079032454
Node: PrepareProtocol objects9032878
Ref: library/sqlite3 prepareprotocol-objects9032990
Ref: 2b089032990
Ref: library/sqlite3 sqlite3 PrepareProtocol9033057
Ref: 19119033057
Ref: PrepareProtocol objects-Footnote-19033326
Node: Exceptions<7>9033368
Ref: library/sqlite3 exceptions9033491
Ref: 2b0a9033491
Ref: library/sqlite3 sqlite3-exceptions9033491
Ref: 2b0b9033491
Ref: library/sqlite3 sqlite3 Warning9033603
Ref: 195b9033603
Ref: library/sqlite3 sqlite3 Error9033904
Ref: 19c99033904
Ref: library/sqlite3 sqlite3 Error sqlite_errorcode9034260
Ref: 67b9034260
Ref: library/sqlite3 sqlite3 Error sqlite_errorname9034389
Ref: 67c9034389
Ref: library/sqlite3 sqlite3 InterfaceError9034549
Ref: 6809034549
Ref: library/sqlite3 sqlite3 DatabaseError9034828
Ref: 2af19034828
Ref: library/sqlite3 sqlite3 DataError9035143
Ref: 19f79035143
Ref: library/sqlite3 sqlite3 OperationalError9035392
Ref: 19f89035392
Ref: library/sqlite3 sqlite3 IntegrityError9035746
Ref: 2b0c9035746
Ref: library/sqlite3 sqlite3 InternalError9035958
Ref: 2b0d9035958
Ref: library/sqlite3 sqlite3 ProgrammingError9036234
Ref: 4f59036234
Ref: library/sqlite3 sqlite3 NotSupportedError9036542
Ref: 2aef9036542
Ref: Exceptions<7>-Footnote-19036975
Ref: Exceptions<7>-Footnote-29037017
Ref: Exceptions<7>-Footnote-39037057
Node: SQLite and Python types9037097
Ref: library/sqlite3 sqlite-and-python-types9037239
Ref: 2b0e9037239
Ref: library/sqlite3 sqlite3-types9037239
Ref: 2ac09037239
Node: Default adapters and converters deprecated9039151
Ref: library/sqlite3 default-adapters-and-converters-deprecated9039302
Ref: 2b0f9039302
Ref: library/sqlite3 sqlite3-default-converters9039302
Ref: 4f29039302
Ref: Default adapters and converters deprecated-Footnote-19040529
Node: Command-line interface9040576
Ref: library/sqlite3 command-line-interface9040695
Ref: 2b109040695
Ref: library/sqlite3 sqlite3-cli9040695
Ref: 4449040695
Ref: library/sqlite3 cmdoption-python-m-sqlite3-h-v-filename-sql-h9041045
Ref: 2b119041045
Ref: library/sqlite3 cmdoption-python-m-sqlite3-h-v-filename-sql-help9041045
Ref: 2b129041045
Ref: library/sqlite3 cmdoption-python-m-sqlite3-h-v-filename-sql-v9041091
Ref: 2b139041091
Ref: library/sqlite3 cmdoption-python-m-sqlite3-h-v-filename-sql-version9041091
Ref: 2b149041091
Node: How-to guides9041189
Ref: library/sqlite3 how-to-guides9041330
Ref: 2b159041330
Ref: library/sqlite3 sqlite3-howtos9041330
Ref: 2ab09041330
Node: How to use placeholders to bind values in SQL queries9041796
Ref: library/sqlite3 how-to-use-placeholders-to-bind-values-in-sql-queries9041957
Ref: 2b169041957
Ref: library/sqlite3 sqlite3-placeholders9041957
Ref: 2d39041957
Ref: How to use placeholders to bind values in SQL queries-Footnote-19044210
Ref: How to use placeholders to bind values in SQL queries-Footnote-29044262
Node: How to adapt custom Python types to SQLite values9044304
Ref: library/sqlite3 how-to-adapt-custom-python-types-to-sqlite-values9044525
Ref: 2b179044525
Ref: library/sqlite3 sqlite3-adapters9044525
Ref: 2ab99044525
Node: How to write adaptable objects9045314
Ref: library/sqlite3 how-to-write-adaptable-objects9045472
Ref: 2b189045472
Ref: library/sqlite3 sqlite3-conform9045472
Ref: 2b099045472
Node: How to register adapter callables9046383
Ref: library/sqlite3 how-to-register-adapter-callables9046541
Ref: 2b199046541
Node: How to convert SQLite values to custom Python types9047185
Ref: library/sqlite3 how-to-convert-sqlite-values-to-custom-python-types9047382
Ref: 2b1a9047382
Ref: library/sqlite3 sqlite3-converters9047382
Ref: 2aba9047382
Node: Adapter and converter recipes9049953
Ref: library/sqlite3 adapter-and-converter-recipes9050139
Ref: 2b1b9050139
Ref: library/sqlite3 sqlite3-adapter-converter-recipes9050139
Ref: 4f39050139
Node: How to use connection shortcut methods9051566
Ref: library/sqlite3 how-to-use-connection-shortcut-methods9051742
Ref: 2b1c9051742
Ref: library/sqlite3 sqlite3-connection-shortcuts9051742
Ref: 2ae89051742
Node: How to use the connection context manager9053013
Ref: library/sqlite3 how-to-use-the-connection-context-manager9053188
Ref: 2b1d9053188
Ref: library/sqlite3 sqlite3-connection-context-manager9053188
Ref: 19129053188
Node: How to work with SQLite URIs9054939
Ref: library/sqlite3 how-to-work-with-sqlite-uris9055111
Ref: 2b1e9055111
Ref: library/sqlite3 sqlite3-uri-tricks9055111
Ref: 2ac79055111
Ref: How to work with SQLite URIs-Footnote-19056414
Node: How to create and use row factories9056454
Ref: library/sqlite3 how-to-create-and-use-row-factories9056623
Ref: 2b1f9056623
Ref: library/sqlite3 sqlite3-howto-row-factory9056623
Ref: 2abb9056623
Node: How to handle non-UTF-8 text encodings9059483
Ref: library/sqlite3 how-to-handle-non-utf-8-text-encodings9059615
Ref: 2b209059615
Ref: library/sqlite3 sqlite3-howto-encoding9059615
Ref: 2af29059615
Ref: How to handle non-UTF-8 text encodings-Footnote-19060955
Node: Explanation9061004
Ref: library/sqlite3 explanation9061127
Ref: 2b219061127
Ref: library/sqlite3 sqlite3-explanation9061127
Ref: 2ab19061127
Ref: library/sqlite3 sqlite3-transaction-control9061172
Ref: 2b229061172
Node: Transaction control9061206
Ref: library/sqlite3 sqlite3-controlling-transactions9061273
Ref: 2ab69061273
Ref: library/sqlite3 transaction-control9061273
Ref: 2b239061273
Node: Transaction control via the autocommit attribute9061766
Ref: library/sqlite3 sqlite3-transaction-control-autocommit9061932
Ref: 4ba9061932
Ref: library/sqlite3 transaction-control-via-the-autocommit-attribute9061932
Ref: 2b249061932
Ref: Transaction control via the autocommit attribute-Footnote-19063691
Ref: Transaction control via the autocommit attribute-Footnote-29063733
Ref: Transaction control via the autocommit attribute-Footnote-39063825
Node: Transaction control via the isolation_level attribute9063867
Ref: library/sqlite3 sqlite3-transaction-control-isolation-level9064033
Ref: 2ac59064033
Ref: library/sqlite3 transaction-control-via-the-isolation-level-attribute9064033
Ref: 2b259064033
Ref: Transaction control via the isolation_level attribute-Footnote-19066107
Ref: Transaction control via the isolation_level attribute-Footnote-29066207
Node: Data Compression and Archiving9066299
Ref: library/archiving doc9066439
Ref: 2a5d9066439
Ref: library/archiving archiving9066439
Ref: 2b269066439
Ref: library/archiving data-compression-and-archiving9066439
Ref: 2b279066439
Ref: library/archiving translation-repo9066439
Ref: 2b289066439
Node: zlib — Compression compatible with gzip9067032
Ref: library/zlib doc9067180
Ref: 2b299067180
Ref: library/zlib module-zlib9067180
Ref: 1339067180
Ref: library/zlib zlib-compression-compatible-with-gzip9067180
Ref: 2b2a9067180
Ref: library/zlib zlib error9068111
Ref: 2b2b9068111
Ref: library/zlib zlib adler329068202
Ref: 195f9068202
Ref: library/zlib zlib compress9068986
Ref: 6429068986
Ref: library/zlib compress-wbits9069526
Ref: 2b309069526
Ref: library/zlib zlib compressobj9070768
Ref: 2b329070768
Ref: library/zlib zlib crc329072634
Ref: 17a89072634
Ref: library/zlib zlib decompress9073335
Ref: d359073335
Ref: library/zlib decompress-wbits9073768
Ref: 2b399073768
Ref: library/zlib zlib decompressobj9075503
Ref: 2b3a9075503
Ref: library/zlib zlib Compress compress9076495
Ref: 2b3b9076495
Ref: library/zlib zlib Compress flush9076847
Ref: 2b3c9076847
Ref: library/zlib zlib Compress copy9077620
Ref: 2b439077620
Ref: library/zlib zlib Decompress unused_data9077988
Ref: 2b449077988
Ref: library/zlib zlib Decompress unconsumed_tail9078334
Ref: 2b459078334
Ref: library/zlib zlib Decompress eof9078782
Ref: 11b19078782
Ref: library/zlib zlib Decompress decompress9079067
Ref: 2b469079067
Ref: library/zlib zlib Decompress flush9080071
Ref: 2b479080071
Ref: library/zlib zlib Decompress copy9080470
Ref: 2b489080470
Ref: library/zlib zlib DEFLATED9080936
Ref: 2b339080936
Ref: library/zlib zlib MAX_WBITS9080999
Ref: 2b319080999
Ref: library/zlib zlib DEF_MEM_LEVEL9081178
Ref: 2b499081178
Ref: library/zlib zlib DEF_BUF_SIZE9081264
Ref: 2b4a9081264
Ref: library/zlib zlib Z_NO_COMPRESSION9081353
Ref: 2b2e9081353
Ref: library/zlib zlib Z_BEST_SPEED9081463
Ref: 2b2c9081463
Ref: library/zlib zlib Z_BEST_COMPRESSION9081569
Ref: 2b2d9081569
Ref: library/zlib zlib Z_DEFAULT_COMPRESSION9081680
Ref: 2b2f9081680
Ref: library/zlib zlib Z_DEFAULT_STRATEGY9081863
Ref: 2b349081863
Ref: library/zlib zlib Z_FILTERED9081951
Ref: 2b359081951
Ref: library/zlib zlib Z_HUFFMAN_ONLY9082051
Ref: 2b369082051
Ref: library/zlib zlib Z_RLE9082142
Ref: 2b379082142
Ref: library/zlib zlib Z_FIXED9082378
Ref: 2b389082378
Ref: library/zlib zlib Z_NO_FLUSH9082606
Ref: 2b3d9082606
Ref: library/zlib zlib Z_PARTIAL_FLUSH9082718
Ref: 2b3e9082718
Ref: library/zlib zlib Z_SYNC_FLUSH9082811
Ref: 2b3f9082811
Ref: library/zlib zlib Z_FULL_FLUSH9082940
Ref: 2b409082940
Ref: library/zlib zlib Z_FINISH9083059
Ref: 2b429083059
Ref: library/zlib zlib Z_BLOCK9083175
Ref: 2b419083175
Ref: library/zlib zlib Z_TREES9083392
Ref: 2b4b9083392
Ref: library/zlib zlib ZLIB_VERSION9083777
Ref: 2b4c9083777
Ref: library/zlib zlib ZLIB_RUNTIME_VERSION9084032
Ref: 11b29084032
Ref: zlib — Compression compatible with gzip-Footnote-19084640
Ref: zlib — Compression compatible with gzip-Footnote-29084685
Ref: zlib — Compression compatible with gzip-Footnote-39084726
Node: gzip — Support for gzip files9084779
Ref: library/gzip doc9084973
Ref: 2b4d9084973
Ref: library/gzip gzip-support-for-gzip-files9084973
Ref: 2b4e9084973
Ref: library/gzip module-gzip9084973
Ref: 679084973
Ref: library/gzip translation-repo9084973
Ref: 2b4f9084973
Ref: library/gzip gzip open9085959
Ref: 2b509085959
Ref: library/gzip gzip BadGzipFile9087491
Ref: a029087491
Ref: library/gzip gzip GzipFile9087744
Ref: 41d9087744
Ref: library/gzip gzip GzipFile peek9090763
Ref: 12519090763
Ref: library/gzip gzip GzipFile mode9091269
Ref: 2b539091269
Ref: library/gzip gzip GzipFile mtime9091462
Ref: 2b519091462
Ref: library/gzip gzip GzipFile name9091802
Ref: 5109091802
Ref: library/gzip gzip compress9093032
Ref: 6419093032
Ref: library/gzip gzip decompress9093977
Ref: 12529093977
Ref: gzip — Support for gzip files-Footnote-19094662
Node: Examples of usage9094726
Ref: library/gzip examples-of-usage9094845
Ref: 2b559094845
Ref: library/gzip gzip-usage-examples9094845
Ref: 2b569094845
Ref: Examples of usage-Footnote-19095929
Node: Command-line interface<2>9095982
Ref: library/gzip command-line-interface9096101
Ref: 2b579096101
Ref: library/gzip gzip-cli9096101
Ref: 2b589096101
Node: Command-line options9096511
Ref: library/gzip command-line-options9096593
Ref: 2b599096593
Ref: library/gzip cmdoption-gzip-arg-file9096654
Ref: 2b5a9096654
Ref: library/gzip cmdoption-gzip-fast9096738
Ref: 2b5b9096738
Ref: library/gzip cmdoption-gzip-best9096825
Ref: 2b5c9096825
Ref: library/gzip cmdoption-gzip-d9096912
Ref: 2b5d9096912
Ref: library/gzip cmdoption-gzip-decompress9096912
Ref: 2b5e9096912
Ref: library/gzip cmdoption-gzip-h9096975
Ref: 2b5f9096975
Ref: library/gzip cmdoption-gzip-help9096975
Ref: 2b609096975
Node: bz2 — Support for bzip2 compression9097028
Ref: library/bz2 doc9097226
Ref: 2b619097226
Ref: library/bz2 bz2-support-for-bzip2-compression9097226
Ref: 2b629097226
Ref: library/bz2 module-bz29097226
Ref: 139097226
Ref: library/bz2 translation-repo9097226
Ref: 2b639097226
Ref: bz2 — Support for bzip2 compression-Footnote-19098182
Node: De compression of files9098245
Ref: library/bz2 de-compression-of-files9098377
Ref: 2b649098377
Ref: library/bz2 bz2 open9098446
Ref: 10d19098446
Ref: library/bz2 bz2 BZ2File9099887
Ref: 86d9099887
Ref: library/bz2 bz2 BZ2File peek9101343
Ref: 2b669101343
Ref: library/bz2 bz2 BZ2File fileno9101899
Ref: 2b679101899
Ref: library/bz2 bz2 BZ2File readable9102023
Ref: 2b689102023
Ref: library/bz2 bz2 BZ2File seekable9102145
Ref: 2b699102145
Ref: library/bz2 bz2 BZ2File writable9102261
Ref: 2b6a9102261
Ref: library/bz2 bz2 BZ2File read19102383
Ref: 2b6b9102383
Ref: library/bz2 bz2 BZ2File readinto9102704
Ref: 2b6c9102704
Ref: library/bz2 bz2 BZ2File mode9102857
Ref: 2b6d9102857
Ref: library/bz2 bz2 BZ2File name9102979
Ref: 2b6e9102979
Node: Incremental de compression9104219
Ref: library/bz2 incremental-de-compression9104383
Ref: 2b709104383
Ref: library/bz2 bz2 BZ2Compressor9104458
Ref: 18719104458
Ref: library/bz2 bz2 BZ2Compressor compress9104798
Ref: 2b719104798
Ref: library/bz2 bz2 BZ2Compressor flush9105146
Ref: 2b729105146
Ref: library/bz2 bz2 BZ2Decompressor9105375
Ref: 186f9105375
Ref: library/bz2 bz2 BZ2Decompressor decompress9105922
Ref: dfa9105922
Ref: library/bz2 bz2 BZ2Decompressor eof9107271
Ref: 2b759107271
Ref: library/bz2 bz2 BZ2Decompressor unused_data9107397
Ref: 2b749107397
Ref: library/bz2 bz2 BZ2Decompressor needs_input9107619
Ref: 2b739107619
Node: One-shot de compression9107843
Ref: library/bz2 one-shot-de-compression9108004
Ref: 2b769108004
Ref: library/bz2 bz2 compress9108073
Ref: 25cc9108073
Ref: library/bz2 bz2 decompress9108372
Ref: 10d29108372
Node: Examples of usage<2>9108730
Ref: library/bz2 bz2-usage-examples9108856
Ref: 2b779108856
Ref: library/bz2 examples-of-usage9108856
Ref: 2b789108856
Node: lzma — Compression using the LZMA algorithm9111786
Ref: library/lzma doc9111987
Ref: 2b799111987
Ref: library/lzma lzma-compression-using-the-lzma-algorithm9111987
Ref: 2b7a9111987
Ref: library/lzma module-lzma9111987
Ref: 8a9111987
Ref: library/lzma translation-repo9111987
Ref: 2b7b9111987
Ref: library/lzma lzma LZMAError9112814
Ref: 2b7c9112814
Ref: lzma — Compression using the LZMA algorithm-Footnote-19113233
Node: Reading and writing compressed files9113297
Ref: library/lzma reading-and-writing-compressed-files9113468
Ref: 2b7d9113468
Ref: library/lzma lzma open9113561
Ref: 2b7e9113561
Ref: library/lzma lzma LZMAFile9115331
Ref: 10479115331
Ref: library/lzma lzma LZMAFile peek9117226
Ref: 2b7f9117226
Ref: library/lzma lzma LZMAFile mode9117812
Ref: 2b809117812
Ref: library/lzma lzma LZMAFile name9117934
Ref: 2b819117934
Node: Compressing and decompressing data in memory9118388
Ref: library/lzma compressing-and-decompressing-data-in-memory9118584
Ref: 2b829118584
Ref: library/lzma lzma LZMACompressor9118693
Ref: 18709118693
Ref: library/lzma lzma LZMACompressor compress9121754
Ref: 2b859121754
Ref: library/lzma lzma LZMACompressor flush9122198
Ref: 2b869122198
Ref: library/lzma lzma LZMADecompressor9122478
Ref: 186e9122478
Ref: library/lzma lzma LZMADecompressor decompress9124001
Ref: e619124001
Ref: library/lzma lzma LZMADecompressor check9125350
Ref: 2b8a9125350
Ref: library/lzma lzma LZMADecompressor eof9125583
Ref: 2b8b9125583
Ref: library/lzma lzma LZMADecompressor unused_data9125676
Ref: 2b899125676
Ref: library/lzma lzma LZMADecompressor needs_input9125847
Ref: 2b889125847
Ref: library/lzma lzma compress9126071
Ref: 2b839126071
Ref: library/lzma lzma decompress9126411
Ref: 2b879126411
Node: Miscellaneous<2>9126912
Ref: library/lzma miscellaneous9127103
Ref: 2b8c9127103
Ref: library/lzma lzma is_check_supported9127150
Ref: 2b8d9127150
Node: Specifying custom filter chains9127512
Ref: library/lzma filter-chain-specs9127670
Ref: 2b849127670
Ref: library/lzma specifying-custom-filter-chains9127670
Ref: 2b8e9127670
Node: Examples<8>9130355
Ref: library/lzma examples9130488
Ref: 2b8f9130488
Node: zipfile — Work with ZIP archives9131856
Ref: library/zipfile doc9132064
Ref: 2b909132064
Ref: library/zipfile module-zipfile9132064
Ref: 1319132064
Ref: library/zipfile translation-repo9132064
Ref: 2b919132064
Ref: library/zipfile zipfile-work-with-zip-archives9132064
Ref: 2b929132064
Ref: library/zipfile zipfile BadZipFile9132905
Ref: 190e9132905
Ref: library/zipfile zipfile BadZipfile9133010
Ref: 2b939133010
Ref: library/zipfile zipfile LargeZipFile9133171
Ref: 2b949133171
Ref: library/zipfile zipfile ZipInfo9133797
Ref: d329133797
Ref: library/zipfile zipfile is_zipfile9134733
Ref: 13749134733
Ref: library/zipfile zipfile ZIP_STORED9135026
Ref: 2b999135026
Ref: library/zipfile zipfile ZIP_DEFLATED9135119
Ref: 2b9a9135119
Ref: library/zipfile zipfile ZIP_BZIP29135265
Ref: 2b9b9135265
Ref: library/zipfile zipfile ZIP_LZMA9135430
Ref: 2b9c9135430
Ref: zipfile — Work with ZIP archives-Footnote-19136464
Ref: zipfile — Work with ZIP archives-Footnote-29136529
Ref: zipfile — Work with ZIP archives-Footnote-39136597
Ref: zipfile — Work with ZIP archives-Footnote-49136665
Node: ZipFile objects9136706
Ref: library/zipfile id19136813
Ref: 2b9d9136813
Ref: library/zipfile zipfile-objects9136813
Ref: 2b959136813
Ref: library/zipfile zipfile ZipFile9136864
Ref: 6c79136864
Ref: library/zipfile zipfile ZipFile close9141821
Ref: 2b9e9141821
Ref: library/zipfile zipfile ZipFile getinfo9141985
Ref: 2b969141985
Ref: library/zipfile zipfile ZipFile infolist9142237
Ref: 2b979142237
Ref: library/zipfile zipfile ZipFile namelist9142495
Ref: 2b9f9142495
Ref: library/zipfile zipfile ZipFile open9142576
Ref: 41e9142576
Ref: library/zipfile zipfile ZipFile extract9145440
Ref: 2ba29145440
Ref: library/zipfile zipfile ZipFile extractall9146816
Ref: 2ba39146816
Ref: library/zipfile zipfile ZipFile printdir9147857
Ref: 2ba49147857
Ref: library/zipfile zipfile ZipFile setpassword9147959
Ref: 2ba59147959
Ref: library/zipfile zipfile ZipFile read9148096
Ref: 2ba19148096
Ref: library/zipfile zipfile ZipFile testzip9149009
Ref: 2ba69149009
Ref: library/zipfile zipfile ZipFile write9149372
Ref: d769149372
Ref: library/zipfile zipfile ZipFile writestr9151165
Ref: 13759151165
Ref: library/zipfile zipfile ZipFile mkdir9152727
Ref: 6c89152727
Ref: library/zipfile zipfile ZipFile filename9153250
Ref: 2ba79153250
Ref: library/zipfile zipfile ZipFile debug9153311
Ref: 2ba89153311
Ref: library/zipfile zipfile ZipFile comment9153531
Ref: 2ba99153531
Node: Path objects9153854
Ref: library/zipfile id29153987
Ref: 2baa9153987
Ref: library/zipfile path-objects9153987
Ref: 2bab9153987
Ref: library/zipfile zipfile Path9154032
Ref: 6cc9154032
Ref: library/zipfile zipfile Path name9155200
Ref: 2bac9155200
Ref: library/zipfile zipfile Path open9155258
Ref: 169f9155258
Ref: library/zipfile zipfile Path iterdir9156150
Ref: 2bad9156150
Ref: library/zipfile zipfile Path is_dir9156234
Ref: 2bae9156234
Ref: library/zipfile zipfile Path is_file9156333
Ref: 2baf9156333
Ref: library/zipfile zipfile Path is_symlink9156428
Ref: 2bb09156428
Ref: library/zipfile zipfile Path exists9156671
Ref: 2bb19156671
Ref: library/zipfile zipfile Path suffix9156799
Ref: 6ca9156799
Ref: library/zipfile zipfile Path stem9157003
Ref: 6c99157003
Ref: library/zipfile zipfile Path suffixes9157137
Ref: 6cb9157137
Ref: library/zipfile zipfile Path read_text9157299
Ref: 18819157299
Ref: library/zipfile zipfile Path read_bytes9157875
Ref: 2bb29157875
Ref: library/zipfile zipfile Path joinpath9157945
Ref: 2bb39157945
Ref: Path objects-Footnote-19158595
Node: PyZipFile objects9158634
Ref: library/zipfile id39158767
Ref: 2bb49158767
Ref: library/zipfile pyzipfile-objects9158767
Ref: 2bb59158767
Ref: library/zipfile zipfile PyZipFile9158970
Ref: 10349158970
Ref: library/zipfile zipfile PyZipFile writepy9159304
Ref: 10339159304
Node: ZipInfo objects9162142
Ref: library/zipfile id49162288
Ref: 2bb69162288
Ref: library/zipfile zipinfo-objects9162288
Ref: 2b989162288
Ref: library/zipfile zipfile ZipInfo from_file9162656
Ref: d319162656
Ref: library/zipfile zipfile ZipInfo is_dir9163742
Ref: d339163742
Ref: library/zipfile zipfile ZipInfo filename9163944
Ref: 2bb79163944
Ref: library/zipfile zipfile ZipInfo date_time9164016
Ref: 2bb89164016
Ref: library/zipfile zipfile ZipInfo compress_type9165592
Ref: 2bb99165592
Ref: library/zipfile zipfile ZipInfo comment9165680
Ref: 2bba9165680
Ref: library/zipfile zipfile ZipInfo extra9165796
Ref: 2bbb9165796
Ref: library/zipfile zipfile ZipInfo create_system9166000
Ref: 2bbc9166000
Ref: library/zipfile zipfile ZipInfo create_version9166078
Ref: 2bbd9166078
Ref: library/zipfile zipfile ZipInfo extract_version9166164
Ref: 2bbe9166164
Ref: library/zipfile zipfile ZipInfo reserved9166251
Ref: 2bbf9166251
Ref: library/zipfile zipfile ZipInfo flag_bits9166304
Ref: 2bc09166304
Ref: library/zipfile zipfile ZipInfo volume9166359
Ref: 2bc19166359
Ref: library/zipfile zipfile ZipInfo internal_attr9166426
Ref: 2bc29166426
Ref: library/zipfile zipfile ZipInfo external_attr9166491
Ref: 2bc39166491
Ref: library/zipfile zipfile ZipInfo header_offset9166561
Ref: 2bc49166561
Ref: library/zipfile zipfile ZipInfo CRC9166637
Ref: 2bc59166637
Ref: library/zipfile zipfile ZipInfo compress_size9166704
Ref: 2bc69166704
Ref: library/zipfile zipfile ZipInfo file_size9166777
Ref: 2ba09166777
Ref: ZipInfo objects-Footnote-19166884
Node: Command-line interface<3>9166952
Ref: library/zipfile command-line-interface9167103
Ref: 2bc79167103
Ref: library/zipfile zipfile-commandline9167103
Ref: 2bc89167103
Node: Command-line options<2>9167894
Ref: library/zipfile command-line-options9167979
Ref: 2bcc9167979
Ref: library/zipfile cmdoption-zipfile-l9168040
Ref: 2bcb9168040
Ref: library/zipfile cmdoption-zipfile-list9168065
Ref: 2bcd9168065
Ref: library/zipfile cmdoption-zipfile-c9168126
Ref: 2bc99168126
Ref: library/zipfile cmdoption-zipfile-create9168175
Ref: 2bce9168175
Ref: library/zipfile cmdoption-zipfile-e9168271
Ref: 2bca9168271
Ref: library/zipfile cmdoption-zipfile-extract9168309
Ref: 2bcf9168309
Ref: library/zipfile cmdoption-zipfile-t9168400
Ref: 2bd09168400
Ref: library/zipfile cmdoption-zipfile-test9168425
Ref: 2bd19168425
Ref: library/zipfile cmdoption-zipfile-metadata-encoding9168503
Ref: 2bd29168503
Node: Decompression pitfalls9168676
Ref: library/zipfile decompression-pitfalls9168803
Ref: 2bd39168803
Node: From file itself9169086
Ref: library/zipfile from-file-itself9169193
Ref: 2bd49169193
Node: File system limitations9169372
Ref: library/zipfile file-system-limitations9169509
Ref: 2bd59169509
Node: Resources limitations9169811
Ref: library/zipfile resources-limitations9169944
Ref: 2bd69169944
Ref: library/zipfile zipfile-resources-limitations9169944
Ref: 2bd79169944
Ref: Resources limitations-Footnote-19170231
Node: Interruption9170278
Ref: library/zipfile interruption9170419
Ref: 2bd89170419
Node: Default behaviors of extraction9170625
Ref: library/zipfile default-behaviors-of-extraction9170736
Ref: 2bd99170736
Node: tarfile — Read and write tar archive files9171001
Ref: library/tarfile doc9171155
Ref: 2bda9171155
Ref: library/tarfile module-tarfile9171155
Ref: de9171155
Ref: library/tarfile tarfile-read-and-write-tar-archive-files9171155
Ref: 2bdb9171155
Ref: library/tarfile translation-repo9171155
Ref: 2bdc9171155
Ref: library/tarfile tarfile open9172743
Ref: eab9172743
Ref: library/tarfile tarfile is_tarfile9179346
Ref: 19809179346
Ref: library/tarfile tarfile TarError9179690
Ref: 2be09179690
Ref: library/tarfile tarfile ReadError9179774
Ref: 19f59179774
Ref: library/tarfile tarfile CompressionError9179940
Ref: 2bde9179940
Ref: library/tarfile tarfile StreamError9180090
Ref: 2be19180090
Ref: library/tarfile tarfile ExtractError9180230
Ref: 2be29180230
Ref: library/tarfile tarfile HeaderError9180411
Ref: 2be39180411
Ref: library/tarfile tarfile FilterError9180536
Ref: 2be59180536
Ref: library/tarfile tarfile FilterError tarinfo9180634
Ref: 2be79180634
Ref: library/tarfile tarfile AbsolutePathError9180773
Ref: 2be99180773
Ref: library/tarfile tarfile OutsideDestinationError9180881
Ref: 2bea9180881
Ref: library/tarfile tarfile SpecialFileError9181012
Ref: 2beb9181012
Ref: library/tarfile tarfile AbsoluteLinkError9181133
Ref: 2bec9181133
Ref: library/tarfile tarfile LinkOutsideDestinationError9181248
Ref: 2bed9181248
Ref: library/tarfile tarfile LinkFallbackError9181399
Ref: 4339181399
Ref: library/tarfile tarfile ENCODING9181816
Ref: 2bee9181816
Ref: library/tarfile tarfile REGTYPE9181986
Ref: 2bef9181986
Ref: library/tarfile tarfile AREGTYPE9182012
Ref: 2bf09182012
Ref: library/tarfile tarfile LNKTYPE9182079
Ref: 2bf29182079
Ref: library/tarfile tarfile SYMTYPE9182154
Ref: 2bf39182154
Ref: library/tarfile tarfile CHRTYPE9182221
Ref: 2bf49182221
Ref: library/tarfile tarfile BLKTYPE9182299
Ref: 2bf59182299
Ref: library/tarfile tarfile DIRTYPE9182373
Ref: 2bf69182373
Ref: library/tarfile tarfile FIFOTYPE9182436
Ref: 2bf79182436
Ref: library/tarfile tarfile CONTTYPE9182510
Ref: 2bf89182510
Ref: library/tarfile tarfile GNUTYPE_LONGNAME9182580
Ref: 2bf99182580
Ref: library/tarfile tarfile GNUTYPE_LONGLINK9182659
Ref: 2bfa9182659
Ref: library/tarfile tarfile GNUTYPE_SPARSE9182738
Ref: 2bfb9182738
Ref: library/tarfile tarfile USTAR_FORMAT9182990
Ref: 2bfd9182990
Ref: library/tarfile tarfile GNU_FORMAT9183057
Ref: 2bfe9183057
Ref: library/tarfile tarfile PAX_FORMAT9183109
Ref: 2bff9183109
Ref: library/tarfile tarfile DEFAULT_FORMAT9183172
Ref: 2c009183172
Ref: tarfile — Read and write tar archive files-Footnote-19184020
Ref: tarfile — Read and write tar archive files-Footnote-29184087
Node: TarFile Objects9184159
Ref: library/tarfile id19184279
Ref: 2c019184279
Ref: library/tarfile tarfile-objects9184279
Ref: 2bdd9184279
Ref: library/tarfile tarfile TarFile9185152
Ref: 12559185152
Ref: library/tarfile tarfile TarFile open9188476
Ref: 19819188476
Ref: library/tarfile tarfile TarFile getmember9188641
Ref: 19949188641
Ref: library/tarfile tarfile TarFile getmembers9188965
Ref: ead9188965
Ref: library/tarfile tarfile TarFile getnames9189153
Ref: 2c039189153
Ref: library/tarfile tarfile TarFile list9189314
Ref: eac9189314
Ref: library/tarfile tarfile TarFile next9189764
Ref: 2c049189764
Ref: library/tarfile tarfile TarFile extractall9189986
Ref: 4319189986
Ref: library/tarfile tarfile TarFile extract9191799
Ref: 4329191799
Ref: library/tarfile tarfile TarFile extractfile9193140
Ref: 2c059193140
Ref: library/tarfile tarfile TarFile errorlevel9193805
Ref: 4349193805
Ref: library/tarfile tarfile TarFile extraction_filter9194736
Ref: 2c069194736
Ref: library/tarfile tarfile TarFile add9196045
Ref: c149196045
Ref: library/tarfile tarfile TarFile addfile9196940
Ref: 17399196940
Ref: library/tarfile tarfile TarFile gettarinfo9197448
Ref: 2c089197448
Ref: library/tarfile tarfile TarFile close9198592
Ref: 2c0b9198592
Ref: library/tarfile tarfile TarFile pax_headers9198735
Ref: 2c0c9198735
Node: TarInfo Objects9198858
Ref: library/tarfile id29199005
Ref: 2c0d9199005
Ref: library/tarfile tarinfo-objects9199005
Ref: 2be89199005
Ref: library/tarfile tarfile TarInfo9200214
Ref: 12569200214
Ref: library/tarfile tarfile TarInfo frombuf9200289
Ref: 2be49200289
Ref: library/tarfile tarfile TarInfo fromtarfile9200503
Ref: 2c0f9200503
Ref: library/tarfile tarfile TarInfo tobuf9200685
Ref: 2c109200685
Ref: library/tarfile tarfile TarInfo name9201126
Ref: 2c0a9201126
Ref: library/tarfile tarfile TarInfo size9201206
Ref: 2c099201206
Ref: library/tarfile tarfile TarInfo mtime9201273
Ref: 2c119201273
Ref: library/tarfile tarfile TarInfo mode9201633
Ref: 2c149201633
Ref: library/tarfile tarfile TarInfo type9201905
Ref: 2bf19201905
Ref: library/tarfile tarfile TarInfo linkname9202349
Ref: 2c159202349
Ref: library/tarfile tarfile TarInfo uid9202761
Ref: 2c169202761
Ref: library/tarfile tarfile TarInfo gid9203040
Ref: 2c179203040
Ref: library/tarfile tarfile TarInfo uname9203320
Ref: 2c189203320
Ref: library/tarfile tarfile TarInfo gname9203557
Ref: 2c199203557
Ref: library/tarfile tarfile TarInfo chksum9203795
Ref: 2c1a9203795
Ref: library/tarfile tarfile TarInfo devmajor9203866
Ref: 2c1b9203866
Ref: library/tarfile tarfile TarInfo devminor9203943
Ref: 2c1c9203943
Ref: library/tarfile tarfile TarInfo offset9204020
Ref: 2c1d9204020
Ref: library/tarfile tarfile TarInfo offset_data9204102
Ref: 2c1e9204102
Ref: library/tarfile tarfile TarInfo sparse9204192
Ref: 2c1f9204192
Ref: library/tarfile tarfile TarInfo pax_headers9204256
Ref: 2c209204256
Ref: library/tarfile tarfile TarInfo replace9204399
Ref: 2c0e9204399
Ref: library/tarfile tarfile TarInfo isfile9205088
Ref: 2c219205088
Ref: library/tarfile tarfile TarInfo isreg9205208
Ref: 2c229205208
Ref: library/tarfile tarfile TarInfo isdir9205274
Ref: 2c239205274
Ref: library/tarfile tarfile TarInfo issym9205356
Ref: 2c249205356
Ref: library/tarfile tarfile TarInfo islnk9205442
Ref: 2c259205442
Ref: library/tarfile tarfile TarInfo ischr9205524
Ref: 2c269205524
Ref: library/tarfile tarfile TarInfo isblk9205613
Ref: 2c279205613
Ref: library/tarfile tarfile TarInfo isfifo9205698
Ref: 2c289205698
Ref: library/tarfile tarfile TarInfo isdev9205776
Ref: 2c299205776
Node: Extraction filters9205897
Ref: library/tarfile extraction-filters9206051
Ref: 2c2a9206051
Ref: library/tarfile tarfile-extraction-filter9206051
Ref: 46f9206051
Ref: Extraction filters-Footnote-19209145
Node: Default named filters9209187
Ref: library/tarfile default-named-filters9209285
Ref: 2c2c9209285
Ref: library/tarfile tarfile fully_trusted_filter9209449
Ref: 2c079209449
Ref: library/tarfile tarfile tar_filter9209597
Ref: 2c2b9209597
Ref: library/tarfile tarfile data_filter9210404
Ref: 4309210404
Node: Filter errors9212107
Ref: library/tarfile filter-errors9212244
Ref: 2c2d9212244
Ref: library/tarfile tarfile-extraction-refuse9212244
Ref: 2be69212244
Node: Hints for further verification9212604
Ref: library/tarfile hints-for-further-verification9212752
Ref: 2c2e9212752
Node: Supporting older Python versions9214481
Ref: library/tarfile supporting-older-python-versions9214650
Ref: 2c2f9214650
Node: Stateful extraction filter example9216200
Ref: library/tarfile stateful-extraction-filter-example9216330
Ref: 2c309216330
Node: Command-Line Interface9217125
Ref: library/tarfile command-line-interface9217275
Ref: 2c319217275
Ref: library/tarfile tarfile-commandline9217275
Ref: 10069217275
Node: Command-line options<3>9218225
Ref: library/tarfile command-line-options9218307
Ref: 2c359218307
Ref: library/tarfile cmdoption-tarfile-l9218370
Ref: 2c349218370
Ref: library/tarfile cmdoption-tarfile-list9218395
Ref: 2c369218395
Ref: library/tarfile cmdoption-tarfile-c9218456
Ref: 2c329218456
Ref: library/tarfile cmdoption-tarfile-create9218505
Ref: 2c379218505
Ref: library/tarfile cmdoption-tarfile-e9218601
Ref: 2c339218601
Ref: library/tarfile cmdoption-tarfile-extract9218641
Ref: 2c389218641
Ref: library/tarfile cmdoption-tarfile-t9218777
Ref: 2c399218777
Ref: library/tarfile cmdoption-tarfile-test9218802
Ref: 2c3a9218802
Ref: library/tarfile cmdoption-tarfile-v9218880
Ref: 2c3b9218880
Ref: library/tarfile cmdoption-tarfile-verbose9218880
Ref: 2c3c9218880
Ref: library/tarfile cmdoption-tarfile-filter9218929
Ref: 2c3d9218929
Node: Examples<9>9219164
Ref: library/tarfile examples9219317
Ref: 2c3e9219317
Ref: library/tarfile tar-examples9219317
Ref: 2bdf9219317
Node: Reading examples9219408
Ref: library/tarfile reading-examples9219497
Ref: 2c3f9219497
Node: Writing examples9220615
Ref: library/tarfile writing-examples9220704
Ref: 2c409220704
Node: Supported tar formats9221876
Ref: library/tarfile supported-tar-formats9222021
Ref: 2c419222021
Ref: library/tarfile tar-formats9222021
Ref: 2bfc9222021
Node: Unicode issues9224233
Ref: library/tarfile tar-unicode9224358
Ref: 2c029224358
Ref: library/tarfile unicode-issues9224358
Ref: 2c429224358
Node: File Formats9226328
Ref: library/fileformats doc9226474
Ref: 2c449226474
Ref: library/fileformats file-formats9226474
Ref: 2c459226474
Ref: library/fileformats fileformats9226474
Ref: 2c469226474
Ref: library/fileformats translation-repo9226474
Ref: 2c479226474
Node: csv — CSV File Reading and Writing9226925
Ref: library/csv doc9227061
Ref: 2c489227061
Ref: library/csv csv-csv-file-reading-and-writing9227061
Ref: 2c499227061
Ref: library/csv module-csv9227061
Ref: 299227061
Ref: csv — CSV File Reading and Writing-Footnote-19228962
Ref: csv — CSV File Reading and Writing-Footnote-29229025
Ref: csv — CSV File Reading and Writing-Footnote-39229084
Node: Module Contents<2>9229126
Ref: library/csv csv-contents9229260
Ref: 2c4a9229260
Ref: library/csv module-contents9229260
Ref: 2c4b9229260
Ref: library/csv csv reader9229366
Ref: 4899229366
Ref: library/csv csv writer9230978
Ref: 48a9230978
Ref: library/csv csv register_dialect9232755
Ref: 2c4e9232755
Ref: library/csv csv unregister_dialect9233242
Ref: 19399233242
Ref: library/csv csv get_dialect9233449
Ref: 19389233449
Ref: library/csv csv list_dialects9233680
Ref: 193a9233680
Ref: library/csv csv field_size_limit9233767
Ref: 19379233767
Ref: library/csv csv DictReader9234034
Ref: 9f09234034
Ref: library/csv csv DictWriter9235892
Ref: 12439235892
Ref: library/csv csv Dialect9237662
Ref: 178e9237662
Ref: library/csv csv excel9238464
Ref: 2c509238464
Ref: library/csv csv excel_tab9238640
Ref: 2c519238640
Ref: library/csv csv unix_dialect9238838
Ref: 12429238838
Ref: library/csv csv Sniffer9239135
Ref: 2c529239135
Ref: library/csv csv Sniffer sniff9239285
Ref: 2c539239285
Ref: library/csv csv Sniffer has_header9239607
Ref: 19fd9239607
Ref: library/csv csv-constants9240758
Ref: 2c549240758
Ref: library/csv csv QUOTE_ALL9240813
Ref: 2c559240813
Ref: library/csv csv QUOTE_MINIMAL9240902
Ref: 2c569240902
Ref: library/csv csv QUOTE_NONNUMERIC9241147
Ref: 16f59241147
Ref: library/csv csv QUOTE_NONE9241675
Ref: 2c579241675
Ref: library/csv csv QUOTE_NOTNULL9242284
Ref: 4879242284
Ref: library/csv csv QUOTE_STRINGS9242722
Ref: 4889242722
Ref: library/csv csv Error9243245
Ref: 2c4f9243245
Ref: Module Contents<2>-Footnote-19243371
Ref: Module Contents<2>-Footnote-29243714
Node: Dialects and Formatting Parameters9244057
Ref: library/csv csv-fmt-params9244214
Ref: 2c4d9244214
Ref: library/csv dialects-and-formatting-parameters9244214
Ref: 2c589244214
Ref: library/csv csv Dialect delimiter9244990
Ref: 2c599244990
Ref: library/csv csv Dialect doublequote9245110
Ref: 2c5a9245110
Ref: library/csv csv Dialect escapechar9245577
Ref: 2c5b9245577
Ref: library/csv csv Dialect lineterminator9246286
Ref: 2c5c9246286
Ref: library/csv csv Dialect quotechar9246641
Ref: 2c5d9246641
Ref: library/csv csv Dialect quoting9247131
Ref: 2c5e9247131
Ref: library/csv csv Dialect skipinitialspace9247443
Ref: 2c5f9247443
Ref: library/csv csv Dialect strict9247728
Ref: 2c609247728
Node: Reader Objects9247868
Ref: library/csv id39248021
Ref: 2c619248021
Ref: library/csv reader-objects9248021
Ref: 2c4c9248021
Ref: library/csv csv csvreader __next__9248214
Ref: 2c629248214
Ref: library/csv csv csvreader dialect9248610
Ref: 2c639248610
Ref: library/csv csv csvreader line_num9248711
Ref: 2c649248711
Ref: library/csv csv DictReader fieldnames9248963
Ref: 2c659248963
Node: Writer Objects9249168
Ref: library/csv writer-objects9249299
Ref: 2c669249299
Ref: library/csv csv csvwriter writerow9249902
Ref: e1a9249902
Ref: library/csv csv csvwriter writerows9250235
Ref: 2c679250235
Ref: library/csv csv csvwriter dialect9250501
Ref: 2c689250501
Ref: library/csv csv DictWriter writeheader9250656
Ref: 12449250656
Node: Examples<10>9251136
Ref: library/csv csv-examples9251244
Ref: 2c699251244
Ref: library/csv examples9251244
Ref: 2c6a9251244
Node: configparser — Configuration file parser9253235
Ref: library/configparser doc9253408
Ref: 2c6b9253408
Ref: library/configparser configparser-configuration-file-parser9253408
Ref: 2c6c9253408
Ref: library/configparser module-configparser9253408
Ref: 229253408
Ref: library/configparser translation-repo9253408
Ref: 2c6d9253408
Ref: configparser — Configuration file parser-Footnote-19254919
Node: Quick Start9254991
Ref: library/configparser quick-start9255109
Ref: 2c6e9255109
Ref: Quick Start-Footnote-19258848
Ref: Quick Start-Footnote-29259050
Node: Supported Datatypes9259252
Ref: library/configparser supported-datatypes9259394
Ref: 2c729259394
Ref: Supported Datatypes-Footnote-19260716
Ref: Supported Datatypes-Footnote-29260918
Node: Fallback Values9261120
Ref: library/configparser fallback-values9261279
Ref: 2c769261279
Node: Supported INI File Structure9262795
Ref: library/configparser supported-ini-file-structure9262951
Ref: 2c6f9262951
Ref: Supported INI File Structure-Footnote-19265670
Ref: Supported INI File Structure-Footnote-29265872
Ref: Supported INI File Structure-Footnote-39266074
Ref: Supported INI File Structure-Footnote-49266276
Ref: Supported INI File Structure-Footnote-59266478
Node: Unnamed Sections9266680
Ref: library/configparser id109266844
Ref: 2c799266844
Ref: library/configparser unnamed-sections9266844
Ref: 2c7a9266844
Node: Interpolation of values9267324
Ref: library/configparser interpolation-of-values9267483
Ref: 2c7b9267483
Ref: library/configparser configparser BasicInterpolation9267719
Ref: 7259267719
Ref: library/configparser configparser ExtendedInterpolation9269008
Ref: 7269269008
Ref: Interpolation of values-Footnote-19270499
Node: Mapping Protocol Access9270701
Ref: library/configparser mapping-protocol-access9270872
Ref: 2c709270872
Ref: Mapping Protocol Access-Footnote-19273755
Node: Customizing Parser Behaviour9273957
Ref: library/configparser customizing-parser-behaviour9274124
Ref: 2c719274124
Ref: library/configparser configparser ConfigParser BOOLEAN_STATES9284868
Ref: 2c7f9284868
Ref: library/configparser configparser ConfigParser SECTCRE9287054
Ref: 2c779287054
Node: Legacy API Examples9288296
Ref: library/configparser legacy-api-examples9288460
Ref: 2c809288460
Node: ConfigParser Objects9292273
Ref: library/configparser configparser-objects9292432
Ref: 2c819292432
Ref: library/configparser id139292432
Ref: 2c829292432
Ref: library/configparser configparser ConfigParser9292495
Ref: 1c89292495
Ref: library/configparser configparser ConfigParser defaults9297914
Ref: 2c859297914
Ref: library/configparser configparser ConfigParser sections9298014
Ref: 2c869298014
Ref: library/configparser configparser ConfigParser add_section9298157
Ref: 12b49298157
Ref: library/configparser configparser ConfigParser has_section9298647
Ref: 2c879298647
Ref: library/configparser configparser ConfigParser options9298823
Ref: 2c889298823
Ref: library/configparser configparser ConfigParser has_option9298933
Ref: 2c899298933
Ref: library/configparser configparser ConfigParser read9299233
Ref: 14b79299233
Ref: library/configparser configparser ConfigParser read_file9300961
Ref: 5099300961
Ref: library/configparser configparser ConfigParser read_string9301438
Ref: 2c7e9301438
Ref: library/configparser configparser ConfigParser read_dict9301787
Ref: 2c7c9301787
Ref: library/configparser configparser ConfigParser get9302484
Ref: 12b29302484
Ref: library/configparser configparser ConfigParser getint9303440
Ref: 2c749303440
Ref: library/configparser configparser ConfigParser getfloat9303729
Ref: 2c759303729
Ref: library/configparser configparser ConfigParser getboolean9304033
Ref: 2c739304033
Ref: library/configparser configparser ConfigParser items9304764
Ref: 2c8a9304764
Ref: library/configparser configparser ConfigParser set9305403
Ref: 12b39305403
Ref: library/configparser configparser ConfigParser write9305688
Ref: 2c7d9305688
Ref: library/configparser configparser ConfigParser remove_option9306385
Ref: 2c8c9306385
Ref: library/configparser configparser ConfigParser remove_section9306699
Ref: 2c8d9306699
Ref: library/configparser configparser ConfigParser optionxform9306911
Ref: 2c839306911
Ref: library/configparser configparser UNNAMED_SECTION9307867
Ref: 2c789307867
Ref: library/configparser configparser MAX_INTERPOLATION_DEPTH9308038
Ref: 2c8e9308038
Node: RawConfigParser Objects9308271
Ref: library/configparser id159308424
Ref: 2c8f9308424
Ref: library/configparser rawconfigparser-objects9308424
Ref: 2c909308424
Ref: library/configparser configparser RawConfigParser9308493
Ref: f9d9308493
Ref: library/configparser configparser RawConfigParser add_section9309886
Ref: 2c919309886
Ref: library/configparser configparser RawConfigParser set9310361
Ref: 2c929310361
Node: Exceptions<8>9311182
Ref: library/configparser exceptions9311306
Ref: 2c939311306
Ref: library/configparser configparser Error9311349
Ref: 2c949311349
Ref: library/configparser configparser NoSectionError9311446
Ref: 2c8b9311446
Ref: library/configparser configparser DuplicateSectionError9311552
Ref: 12b59311552
Ref: library/configparser configparser DuplicateOptionError9311961
Ref: 12b69311961
Ref: library/configparser configparser NoOptionError9312321
Ref: 2c959312321
Ref: library/configparser configparser InterpolationError9312455
Ref: 2c969312455
Ref: library/configparser configparser InterpolationDepthError9312600
Ref: 2c979312600
Ref: library/configparser configparser InterpolationMissingOptionError9312860
Ref: 2c989312860
Ref: library/configparser configparser InterpolationSyntaxError9313049
Ref: 2c999313049
Ref: library/configparser configparser MissingSectionHeaderError9313277
Ref: 2c9a9313277
Ref: library/configparser configparser ParsingError9313422
Ref: 5089313422
Ref: library/configparser configparser MultilineContinuationError9313724
Ref: 2c849313724
Node: tomllib — Parse TOML files9313914
Ref: library/tomllib doc9314082
Ref: 2c9b9314082
Ref: library/tomllib module-tomllib9314082
Ref: fc9314082
Ref: library/tomllib tomllib-parse-toml-files9314082
Ref: 2c9c9314082
Ref: library/tomllib translation-repo9314082
Ref: 2c9d9314082
Ref: library/tomllib tomllib load9314918
Ref: 2c9e9314918
Ref: library/tomllib tomllib loads9315643
Ref: 2ca19315643
Ref: library/tomllib tomllib TOMLDecodeError9316062
Ref: 2ca09316062
Ref: tomllib — Parse TOML files-Footnote-19316236
Ref: tomllib — Parse TOML files-Footnote-29316300
Ref: tomllib — Parse TOML files-Footnote-39316328
Ref: tomllib — Parse TOML files-Footnote-49316370
Node: Examples<11>9316412
Ref: library/tomllib examples9316514
Ref: 2ca29316514
Node: Conversion Table9316854
Ref: library/tomllib conversion-table9316956
Ref: 2ca39316956
Ref: library/tomllib toml-to-py-table9317009
Ref: 2c9f9317009
Node: netrc — netrc file processing9318367
Ref: library/netrc doc9318542
Ref: 2ca49318542
Ref: library/netrc module-netrc9318542
Ref: 9b9318542
Ref: library/netrc netrc-netrc-file-processing9318542
Ref: 2ca59318542
Ref: library/netrc translation-repo9318542
Ref: 2ca69318542
Ref: library/netrc netrc netrc9318861
Ref: 1a209318861
Ref: library/netrc netrc NetrcParseError9320666
Ref: 2ca79320666
Ref: library/netrc netrc NetrcParseError msg9320892
Ref: 2ca89320892
Ref: library/netrc netrc NetrcParseError filename9320962
Ref: 2ca99320962
Ref: library/netrc netrc NetrcParseError lineno9321032
Ref: 2caa9321032
Ref: netrc — netrc file processing-Footnote-19321181
Node: netrc Objects9321246
Ref: library/netrc id19321327
Ref: 2cab9321327
Ref: library/netrc netrc-objects9321327
Ref: 2cac9321327
Ref: library/netrc netrc netrc authenticators9321432
Ref: 2cad9321432
Ref: library/netrc netrc netrc __repr__9321778
Ref: 2cae9321778
Ref: library/netrc netrc netrc hosts9322002
Ref: 2caf9322002
Ref: library/netrc netrc netrc macros9322200
Ref: 2cb09322200
Node: plistlib — Generate and parse Apple plist files9322283
Ref: library/plistlib doc9322421
Ref: 2cb19322421
Ref: library/plistlib module-plistlib9322421
Ref: ab9322421
Ref: library/plistlib plistlib-generate-and-parse-apple-plist-files9322421
Ref: 2cb29322421
Ref: library/plistlib translation-repo9322421
Ref: 2cb39322421
Ref: library/plistlib plistlib load9323859
Ref: 9599323859
Ref: library/plistlib plistlib loads9325105
Ref: 95a9325105
Ref: library/plistlib plistlib dump9325452
Ref: 95b9325452
Ref: library/plistlib plistlib dumps9326854
Ref: 95c9326854
Ref: library/plistlib plistlib UID9327212
Ref: a2e9327212
Ref: library/plistlib plistlib UID data9327392
Ref: 2cb49327392
Ref: library/plistlib plistlib FMT_XML9327578
Ref: fb29327578
Ref: library/plistlib plistlib FMT_BINARY9327672
Ref: fb39327672
Ref: library/plistlib plistlib InvalidFileException9327817
Ref: 1aa19327817
Ref: plistlib — Generate and parse Apple plist files-Footnote-19328006
Ref: plistlib — Generate and parse Apple plist files-Footnote-29328074
Node: Examples<12>9328173
Ref: library/plistlib examples9328271
Ref: 2cb59328271
Node: Cryptographic Services9329126
Ref: library/crypto doc9329275
Ref: 2cb69329275
Ref: library/crypto crypto9329275
Ref: 2cb79329275
Ref: library/crypto cryptographic-services9329275
Ref: 2cb89329275
Ref: library/crypto translation-repo9329275
Ref: 2cb99329275
Node: hashlib — Secure hashes and message digests9329691
Ref: library/hashlib doc9329853
Ref: 2cba9329853
Ref: library/hashlib hashlib-secure-hashes-and-message-digests9329853
Ref: 2cbb9329853
Ref: library/hashlib module-hashlib9329853
Ref: 689329853
Ref: hashlib — Secure hashes and message digests-Footnote-19330765
Ref: hashlib — Secure hashes and message digests-Footnote-29330832
Ref: hashlib — Secure hashes and message digests-Footnote-39330889
Ref: hashlib — Secure hashes and message digests-Footnote-49330939
Ref: hashlib — Secure hashes and message digests-Footnote-59331009
Node: Hash algorithms9331068
Ref: library/hashlib hash-algorithms9331179
Ref: 2cbc9331179
Ref: library/hashlib id19331179
Ref: 2cbd9331179
Ref: library/hashlib hashlib-usedforsecurity9333304
Ref: 2cc69333304
Ref: Hash algorithms-Footnote-19333989
Ref: Hash algorithms-Footnote-29334097
Node: Usage9334144
Ref: library/hashlib usage9334276
Ref: 2cc79334276
Node: Constructors9334928
Ref: library/hashlib constructors9335055
Ref: 2cc89335055
Ref: library/hashlib hashlib new9335100
Ref: 1ad59335100
Ref: library/hashlib hashlib md59335662
Ref: 16469335662
Ref: library/hashlib hashlib sha19335723
Ref: 2cc19335723
Ref: library/hashlib hashlib sha2249335785
Ref: 2cc29335785
Ref: library/hashlib hashlib sha2569335849
Ref: 16699335849
Ref: library/hashlib hashlib sha3849335913
Ref: 2cc39335913
Ref: library/hashlib hashlib sha5129335977
Ref: 2cc49335977
Ref: library/hashlib hashlib sha3_2249336041
Ref: cc89336041
Ref: library/hashlib hashlib sha3_2569336107
Ref: cc99336107
Ref: library/hashlib hashlib sha3_3849336173
Ref: cca9336173
Ref: library/hashlib hashlib sha3_5129336239
Ref: ccb9336239
Node: Attributes9336403
Ref: library/hashlib attributes9336537
Ref: 2cc99336537
Ref: library/hashlib hashlib algorithms_guaranteed9336638
Ref: 13c09336638
Ref: library/hashlib hashlib algorithms_available9336973
Ref: 13c19336973
Node: Hash Objects9337404
Ref: library/hashlib hash-objects9337555
Ref: 2cca9337555
Ref: library/hashlib hashlib hash digest_size9337708
Ref: 2ccb9337708
Ref: library/hashlib hashlib hash block_size9337783
Ref: 2ccc9337783
Ref: library/hashlib hashlib hash name9337917
Ref: f809337917
Ref: library/hashlib hashlib hash update9338338
Ref: 2cbe9338338
Ref: library/hashlib hashlib hash digest9338614
Ref: 2cbf9338614
Ref: library/hashlib hashlib hash hexdigest9338854
Ref: 2cc09338854
Ref: library/hashlib hashlib hash copy9339125
Ref: 2ccd9339125
Node: SHAKE variable length digests9339312
Ref: library/hashlib shake-variable-length-digests9339465
Ref: 2cce9339465
Ref: library/hashlib hashlib shake_1289339544
Ref: ccc9339544
Ref: library/hashlib hashlib shake_2569339611
Ref: ccd9339611
Ref: library/hashlib hashlib shake digest9339939
Ref: 1bc99339939
Ref: library/hashlib hashlib shake hexdigest9340170
Ref: 1bca9340170
Node: File hashing9340604
Ref: library/hashlib file-hashing9340759
Ref: 2ccf9340759
Ref: library/hashlib hashlib file_digest9340904
Ref: 6479340904
Node: Key derivation9342611
Ref: library/hashlib key-derivation9342743
Ref: 2cd09342743
Ref: library/hashlib hashlib pbkdf2_hmac9343054
Ref: 5129343054
Ref: library/hashlib hashlib scrypt9344806
Ref: c5f9344806
Ref: Key derivation-Footnote-19345544
Ref: Key derivation-Footnote-29345606
Ref: Key derivation-Footnote-39345693
Ref: Key derivation-Footnote-49345804
Node: BLAKE29345863
Ref: library/hashlib blake29345974
Ref: 2cd19345974
Ref: library/hashlib hashlib-blake29345974
Ref: 1f369345974
Ref: BLAKE2-Footnote-19346692
Ref: BLAKE2-Footnote-29346723
Ref: BLAKE2-Footnote-39346782
Node: Creating hash objects9346860
Ref: library/hashlib creating-hash-objects9346945
Ref: 2cd29346945
Ref: library/hashlib hashlib blake2b9347074
Ref: 6459347074
Ref: library/hashlib hashlib blake2s9347310
Ref: 6469347310
Ref: Creating hash objects-Footnote-19350354
Node: Constants<5>9350405
Ref: library/hashlib constants9350511
Ref: 2cd39350511
Ref: library/hashlib hashlib blake2b SALT_SIZE9350552
Ref: 2cd49350552
Ref: library/hashlib hashlib blake2s SALT_SIZE9350581
Ref: 2cd59350581
Ref: library/hashlib hashlib blake2b PERSON_SIZE9350666
Ref: 2cd69350666
Ref: library/hashlib hashlib blake2s PERSON_SIZE9350697
Ref: 2cd79350697
Ref: library/hashlib hashlib blake2b MAX_KEY_SIZE9350802
Ref: 2cd89350802
Ref: library/hashlib hashlib blake2s MAX_KEY_SIZE9350834
Ref: 2cd99350834
Ref: library/hashlib hashlib blake2b MAX_DIGEST_SIZE9350885
Ref: 2cda9350885
Ref: library/hashlib hashlib blake2s MAX_DIGEST_SIZE9350920
Ref: 2cdb9350920
Node: Examples<13>9351011
Ref: library/hashlib examples9351103
Ref: 2cdc9351103
Node: Simple hashing9351279
Ref: library/hashlib simple-hashing9351379
Ref: 2cdd9351379
Node: Using different digest sizes9352833
Ref: library/hashlib using-different-digest-sizes9352955
Ref: 2cde9352955
Node: Keyed hashing9354098
Ref: library/hashlib keyed-hashing9354224
Ref: 2cdf9354224
Ref: Keyed hashing-Footnote-19356235
Node: Randomized hashing9356278
Ref: library/hashlib randomized-hashing9356391
Ref: 2ce09356391
Ref: Randomized hashing-Footnote-19358995
Ref: Randomized hashing-Footnote-29359047
Node: Personalization9359082
Ref: library/hashlib personalization9359191
Ref: 2ce19359191
Ref: Personalization-Footnote-19361186
Node: Tree mode9361256
Ref: library/hashlib tree-mode9361338
Ref: 2ce29361338
Node: Credits9362589
Ref: library/hashlib credits9362660
Ref: 2ce39362660
Ref: library/hashlib hashlib-seealso9364091
Ref: 2cc59364091
Ref: Credits-Footnote-19365077
Ref: Credits-Footnote-29365108
Ref: Credits-Footnote-39365169
Ref: Credits-Footnote-49365247
Ref: Credits-Footnote-59365284
Ref: Credits-Footnote-69365327
Node: hmac — Keyed-Hashing for Message Authentication9365370
Ref: library/hmac doc9365604
Ref: 2ce49365604
Ref: library/hmac hmac-keyed-hashing-for-message-authentication9365604
Ref: 2ce59365604
Ref: library/hmac module-hmac9365604
Ref: 6a9365604
Ref: library/hmac translation-repo9365604
Ref: 2ce69365604
Ref: library/hmac hmac new9366071
Ref: ab49366071
Ref: library/hmac hmac digest9366899
Ref: b569366899
Ref: library/hmac hmac HMAC9367499
Ref: b579367499
Ref: library/hmac hmac HMAC update9367569
Ref: f829367569
Ref: library/hmac hmac HMAC digest9367917
Ref: 2ce79367917
Ref: library/hmac hmac HMAC hexdigest9368521
Ref: 2ce89368521
Ref: library/hmac hmac HMAC copy9369103
Ref: 15cd9369103
Ref: library/hmac hmac HMAC digest_size9369341
Ref: f859369341
Ref: library/hmac hmac HMAC block_size9369428
Ref: f839369428
Ref: library/hmac hmac HMAC name9369550
Ref: f849369550
Ref: library/hmac hmac compare_digest9369871
Ref: 110d9369871
Ref: hmac — Keyed-Hashing for Message Authentication-Footnote-19370810
Ref: hmac — Keyed-Hashing for Message Authentication-Footnote-29370874
Node: secrets — Generate secure random numbers for managing secrets9370933
Ref: library/secrets doc9371113
Ref: 2ce99371113
Ref: library/secrets module-secrets9371113
Ref: c09371113
Ref: library/secrets secrets-generate-secure-random-numbers-for-managing-secrets9371113
Ref: 2cea9371113
Ref: library/secrets translation-repo9371113
Ref: 2ceb9371113
Ref: secrets — Generate secure random numbers for managing secrets-Footnote-19371969
Ref: secrets — Generate secure random numbers for managing secrets-Footnote-29372036
Node: Random numbers9372078
Ref: library/secrets random-numbers9372218
Ref: 2cec9372218
Ref: library/secrets secrets SystemRandom9372386
Ref: 2ced9372386
Ref: library/secrets secrets choice9372603
Ref: 2cee9372603
Ref: library/secrets secrets randbelow9372705
Ref: 2cef9372705
Ref: library/secrets secrets randbits9372831
Ref: 2cf09372831
Node: Generating tokens9372921
Ref: library/secrets generating-tokens9373085
Ref: 2cf19373085
Ref: library/secrets secrets token_bytes9373299
Ref: 28af9373299
Ref: library/secrets secrets token_hex9373608
Ref: 18c99373608
Ref: library/secrets secrets token_urlsafe9373964
Ref: 2cf39373964
Node: How many bytes should tokens use?9374414
Ref: library/secrets how-many-bytes-should-tokens-use9374501
Ref: 2cf49374501
Ref: library/secrets secrets DEFAULT_ENTROPY9375387
Ref: 2cf29375387
Ref: How many bytes should tokens use?-Footnote-19375644
Node: Other functions9375701
Ref: library/secrets other-functions9375877
Ref: 2cf59375877
Ref: library/secrets secrets compare_digest9375928
Ref: 2cf69375928
Ref: Other functions-Footnote-19376280
Node: Recipes and best practices9376337
Ref: library/secrets recipes-and-best-practices9376487
Ref: 2cf79376487
Ref: Recipes and best practices-Footnote-19378221
Ref: Recipes and best practices-Footnote-29378277
Node: Generic Operating System Services9378307
Ref: library/allos doc9378476
Ref: 2cf89378476
Ref: library/allos allos9378476
Ref: 2cf99378476
Ref: library/allos generic-operating-system-services9378476
Ref: 2cfa9378476
Ref: library/allos translation-repo9378476
Ref: 2cfb9378476
Node: os — Miscellaneous operating system interfaces9379396
Ref: library/os doc9379565
Ref: 2cfc9379565
Ref: library/os module-os9379565
Ref: a19379565
Ref: library/os os-miscellaneous-operating-system-interfaces9379565
Ref: 2cfd9379565
Ref: library/os os error9381843
Ref: 2cff9381843
Ref: library/os os name9381931
Ref: 2d009381931
Ref: library/os os-filenames9382375
Ref: 2c439382375
Ref: os — Miscellaneous operating system interfaces-Footnote-19382802
Node: File Names Command Line Arguments and Environment Variables9382864
Ref: library/os file-names-command-line-arguments-and-environment-variables9383034
Ref: 2d019383034
Ref: library/os filesystem-encoding9383034
Ref: 298c9383034
Node: Python UTF-8 Mode9384369
Ref: library/os python-utf-8-mode9384566
Ref: 2d029384566
Ref: library/os utf8-mode9384566
Ref: 6599384566
Ref: Python UTF-8 Mode-Footnote-19387396
Ref: Python UTF-8 Mode-Footnote-29387438
Node: Process Parameters9387480
Ref: library/os os-procinfo9387638
Ref: 2d039387638
Ref: library/os process-parameters9387638
Ref: 2d049387638
Ref: library/os os ctermid9387792
Ref: 2d059387792
Ref: library/os os environ9387959
Ref: 11fe9387959
Ref: library/os os environb9389915
Ref: 125c9389915
Ref: library/os os fsencode9390652
Ref: c769390652
Ref: library/os os fsdecode9391041
Ref: c759391041
Ref: library/os os fspath9391434
Ref: c749391434
Ref: library/os os PathLike9391830
Ref: c729391830
Ref: library/os os PathLike __fspath__9392009
Ref: c739392009
Ref: library/os os getenv9392264
Ref: 2d079392264
Ref: library/os os getenvb9392924
Ref: 125b9392924
Ref: library/os os get_exec_path9393481
Ref: 2d089393481
Ref: library/os os getegid9393863
Ref: 2d099393863
Ref: library/os os geteuid9394104
Ref: 19189394104
Ref: library/os os getgid9394238
Ref: 2d0a9394238
Ref: library/os os getgrouplist9394464
Ref: 11589394464
Ref: library/os os getgroups9394859
Ref: 2d0b9394859
Ref: library/os os getlogin9396066
Ref: 16339396066
Ref: library/os os getpgid9396557
Ref: 2d0d9396557
Ref: library/os os getpgrp9396792
Ref: 2d0e9396792
Ref: library/os os getpid9396920
Ref: 2cfe9396920
Ref: library/os os getppid9397089
Ref: 17609397089
Ref: library/os os getpriority9397469
Ref: 11439397469
Ref: library/os os PRIO_PROCESS9398089
Ref: 2d0f9398089
Ref: library/os os PRIO_PGRP9398115
Ref: 2d109398115
Ref: library/os os PRIO_USER9398138
Ref: 2d119398138
Ref: library/os os PRIO_DARWIN_THREAD9398338
Ref: 2d129398338
Ref: library/os os PRIO_DARWIN_PROCESS9398370
Ref: 2d139398370
Ref: library/os os PRIO_DARWIN_BG9398403
Ref: 2d149398403
Ref: library/os os PRIO_DARWIN_NONUI9398431
Ref: 2d159398431
Ref: library/os os getresuid9398630
Ref: 135f9398630
Ref: library/os os getresgid9398853
Ref: 135e9398853
Ref: library/os os getuid9399077
Ref: 16329399077
Ref: library/os os initgroups9399299
Ref: 13629399299
Ref: library/os os putenv9399621
Ref: 9259399621
Ref: library/os os setegid9400720
Ref: 2d179400720
Ref: library/os os seteuid9400872
Ref: 2d189400872
Ref: library/os os setgid9401023
Ref: 2d199401023
Ref: library/os os setgroups9401162
Ref: 2d0c9401162
Ref: library/os os setns9401820
Ref: 18e59401820
Ref: library/os os setpgrp9403342
Ref: 2d1b9403342
Ref: library/os os setpgid9403588
Ref: 2d1c9403588
Ref: library/os os setpriority9403865
Ref: 11449403865
Ref: library/os os setregid9404629
Ref: 2d1d9404629
Ref: library/os os setresgid9404798
Ref: 13609404798
Ref: library/os os setresuid9405010
Ref: 13619405010
Ref: library/os os setreuid9405221
Ref: 2d1e9405221
Ref: library/os os getsid9405389
Ref: 2d1f9405389
Ref: library/os os setsid9405560
Ref: 1b659405560
Ref: library/os os setuid9405725
Ref: 2d209405725
Ref: library/os os strerror9405864
Ref: 2d219405864
Ref: library/os os supports_bytes_environ9406110
Ref: 125a9406110
Ref: library/os os umask9406277
Ref: 2d229406277
Ref: library/os os uname9406482
Ref: 115a9406482
Ref: library/os os unsetenv9407793
Ref: 9249407793
Ref: library/os os unshare9408534
Ref: 18e69408534
Ref: library/os os-unshare-clone-flags9409248
Ref: 2d1a9409248
Ref: library/os os CLONE_FILES9409418
Ref: 2d249409418
Ref: library/os os CLONE_FS9409443
Ref: 2d259409443
Ref: library/os os CLONE_NEWCGROUP9409465
Ref: 2d269409465
Ref: library/os os CLONE_NEWIPC9409494
Ref: 2d279409494
Ref: library/os os CLONE_NEWNET9409520
Ref: 2d289409520
Ref: library/os os CLONE_NEWNS9409546
Ref: 2d299409546
Ref: library/os os CLONE_NEWPID9409571
Ref: 2d2a9409571
Ref: library/os os CLONE_NEWTIME9409597
Ref: 2d2b9409597
Ref: library/os os CLONE_NEWUSER9409624
Ref: 2d2c9409624
Ref: library/os os CLONE_NEWUTS9409651
Ref: 2d2d9409651
Ref: library/os os CLONE_SIGHAND9409677
Ref: 2d2e9409677
Ref: library/os os CLONE_SYSVSEM9409704
Ref: 2d2f9409704
Ref: library/os os CLONE_THREAD9409731
Ref: 2d309409731
Ref: library/os os CLONE_VM9409757
Ref: 2d319409757
Ref: Process Parameters-Footnote-19409816
Ref: Process Parameters-Footnote-29409858
Ref: Process Parameters-Footnote-39409900
Ref: Process Parameters-Footnote-49409945
Ref: Process Parameters-Footnote-59409995
Ref: Process Parameters-Footnote-69410042
Node: File Object Creation9410089
Ref: library/os file-object-creation9410256
Ref: 2d329410256
Ref: library/os os-newstreams9410256
Ref: 2d339410256
Ref: library/os os fdopen9410432
Ref: 20e39410432
Node: File Descriptor Operations9410752
Ref: library/os file-descriptor-operations9410922
Ref: 2d349410922
Ref: library/os os-fd-ops9410922
Ref: 2d359410922
Ref: library/os os close9411764
Ref: b909411764
Ref: library/os os closerange9412209
Ref: 2d369412209
Ref: library/os os copy_file_range9412558
Ref: 2d379412558
Ref: library/os os device_encoding9414236
Ref: 19db9414236
Ref: library/os os dup9414648
Ref: 1b6d9414648
Ref: library/os os dup29415063
Ref: b7f9415063
Ref: library/os os fchmod9415565
Ref: 21c9415565
Ref: library/os os fchown9416143
Ref: db89416143
Ref: library/os os fdatasync9416710
Ref: db99416710
Ref: library/os os fpathconf9416941
Ref: 2d399416941
Ref: library/os os fstat9417974
Ref: dba9417974
Ref: library/os os fstatvfs9418234
Ref: dbb9418234
Ref: library/os os fsync9418512
Ref: dbc9418512
Ref: library/os os ftruncate9418998
Ref: dbd9418998
Ref: library/os os get_blocking9419443
Ref: e6c9419443
Ref: library/os os grantpt9420022
Ref: 17969420022
Ref: library/os os isatty9420406
Ref: 19da9420406
Ref: library/os os lockf9420560
Ref: 11579420560
Ref: library/os os F_LOCK9421082
Ref: 2d3b9421082
Ref: library/os os F_TLOCK9421102
Ref: 2d3c9421102
Ref: library/os os F_ULOCK9421123
Ref: 2d3d9421123
Ref: library/os os F_TEST9421144
Ref: 2d3e9421144
Ref: library/os os login_tty9421301
Ref: 186d9421301
Ref: library/os os lseek9421660
Ref: 115b9421660
Ref: library/os os SEEK_SET9422517
Ref: 12d49422517
Ref: library/os os SEEK_CUR9422539
Ref: 12d59422539
Ref: library/os os SEEK_END9422561
Ref: 12d69422561
Ref: library/os os SEEK_HOLE9423140
Ref: 2d3f9423140
Ref: library/os os SEEK_DATA9423163
Ref: 2d409423163
Ref: library/os os open9423888
Ref: dc09423888
Ref: library/os os O_RDONLY9425957
Ref: 2d419425957
Ref: library/os os O_WRONLY9425979
Ref: 2d429425979
Ref: library/os os O_RDWR9426001
Ref: 2d449426001
Ref: library/os os O_APPEND9426021
Ref: 2d459426021
Ref: library/os os O_CREAT9426043
Ref: 2d469426043
Ref: library/os os O_EXCL9426064
Ref: 2a249426064
Ref: library/os os O_TRUNC9426084
Ref: 2d479426084
Ref: library/os os O_DSYNC9426167
Ref: 2d489426167
Ref: library/os os O_RSYNC9426188
Ref: 2d499426188
Ref: library/os os O_SYNC9426209
Ref: 2d4a9426209
Ref: library/os os O_NDELAY9426229
Ref: 2d4b9426229
Ref: library/os os O_NONBLOCK9426251
Ref: e6e9426251
Ref: library/os os O_NOCTTY9426275
Ref: 2d4c9426275
Ref: library/os os O_CLOEXEC9426297
Ref: 10ba9426297
Ref: library/os os O_BINARY9426435
Ref: 2d439426435
Ref: library/os os O_NOINHERIT9426457
Ref: 2d4d9426457
Ref: library/os os O_SHORT_LIVED9426482
Ref: 2d4e9426482
Ref: library/os os O_TEMPORARY9426509
Ref: 2d4f9426509
Ref: library/os os O_RANDOM9426534
Ref: 2d509426534
Ref: library/os os O_SEQUENTIAL9426556
Ref: 2d519426556
Ref: library/os os O_TEXT9426582
Ref: 2d529426582
Ref: library/os os O_EVTONLY9426660
Ref: 8209426660
Ref: library/os os O_FSYNC9426683
Ref: 8219426683
Ref: library/os os O_SYMLINK9426704
Ref: 8229426704
Ref: library/os os O_NOFOLLOW_ANY9426727
Ref: 8239426727
Ref: library/os os O_ASYNC9426935
Ref: 2d539426935
Ref: library/os os O_DIRECT9426956
Ref: 2d549426956
Ref: library/os os O_DIRECTORY9426978
Ref: 2d559426978
Ref: library/os os O_NOFOLLOW9427003
Ref: 2d569427003
Ref: library/os os O_NOATIME9427027
Ref: 2d579427027
Ref: library/os os O_PATH9427050
Ref: fab9427050
Ref: library/os os O_TMPFILE9427070
Ref: fac9427070
Ref: library/os os O_SHLOCK9427093
Ref: 147d9427093
Ref: library/os os O_EXLOCK9427115
Ref: 147e9427115
Ref: library/os os openpty9427389
Ref: 2d589427389
Ref: library/os os pipe9427833
Ref: 190a9427833
Ref: library/os os pipe29428173
Ref: 112d9428173
Ref: library/os os posix_fallocate9428564
Ref: dc29428564
Ref: library/os os posix_fadvise9428827
Ref: dc19428827
Ref: library/os os POSIX_FADV_NORMAL9429434
Ref: 2d599429434
Ref: library/os os POSIX_FADV_SEQUENTIAL9429465
Ref: 2d5a9429465
Ref: library/os os POSIX_FADV_RANDOM9429500
Ref: 2d5b9429500
Ref: library/os os POSIX_FADV_NOREUSE9429531
Ref: 2d5c9429531
Ref: library/os os POSIX_FADV_WILLNEED9429563
Ref: 2d5d9429563
Ref: library/os os POSIX_FADV_DONTNEED9429596
Ref: 2d5e9429596
Ref: library/os os pread9429833
Ref: b7b9429833
Ref: library/os os posix_openpt9430225
Ref: 17959430225
Ref: library/os os preadv9430822
Ref: b799430822
Ref: library/os os RWF_NOWAIT9431867
Ref: 2d609431867
Ref: library/os os RWF_HIPRI9432371
Ref: 2d5f9432371
Ref: library/os os ptsname9432764
Ref: 17989432764
Ref: library/os os pwrite9433306
Ref: b7e9433306
Ref: library/os os pwritev9433595
Ref: b7c9433595
Ref: library/os os RWF_DSYNC9434639
Ref: 2d619434639
Ref: library/os os RWF_SYNC9434918
Ref: 2d629434918
Ref: library/os os RWF_APPEND9435195
Ref: 1ad49435195
Ref: library/os os read9435752
Ref: dc39435752
Ref: library/os os sendfile9436720
Ref: b289436720
Ref: library/os os SF_NODISKIO9438217
Ref: 2d639438217
Ref: library/os os SF_MNOWAIT9438242
Ref: 2d649438242
Ref: library/os os SF_SYNC9438266
Ref: 2d659438266
Ref: library/os os SF_NOCACHE9438464
Ref: 2d669438464
Ref: library/os os set_blocking9438748
Ref: e6d9438748
Ref: library/os os splice9439353
Ref: 81f9439353
Ref: library/os os SPLICE_F_MOVE9440773
Ref: 2d679440773
Ref: library/os os SPLICE_F_NONBLOCK9440800
Ref: 2d689440800
Ref: library/os os SPLICE_F_MORE9440831
Ref: 2d699440831
Ref: library/os os readv9440888
Ref: b7a9440888
Ref: library/os os tcgetpgrp9441509
Ref: 2d6a9441509
Ref: library/os os tcsetpgrp9441737
Ref: 2d6b9441737
Ref: library/os os ttyname9441979
Ref: 2d6c9441979
Ref: library/os os unlockpt9442233
Ref: 17979442233
Ref: library/os os write9442609
Ref: dc99442609
Ref: library/os os writev9443477
Ref: b7d9443477
Ref: File Descriptor Operations-Footnote-19444176
Ref: File Descriptor Operations-Footnote-29444218
Ref: File Descriptor Operations-Footnote-39444262
Ref: File Descriptor Operations-Footnote-49444325
Ref: File Descriptor Operations-Footnote-59444367
Node: Querying the size of a terminal9444409
Ref: library/os querying-the-size-of-a-terminal9444543
Ref: 2d6d9444543
Ref: library/os terminal-size9444543
Ref: 2d6e9444543
Ref: library/os os get_terminal_size9444649
Ref: 11469444649
Ref: library/os os terminal_size9445290
Ref: 2a509445290
Ref: library/os os terminal_size columns9445411
Ref: 2d6f9445411
Ref: library/os os terminal_size lines9445495
Ref: 2d709445495
Node: Inheritance of File Descriptors9445578
Ref: library/os fd-inheritance9445712
Ref: f309445712
Ref: library/os inheritance-of-file-descriptors9445712
Ref: 2d719445712
Ref: library/os os get_inheritable9446853
Ref: f319446853
Ref: library/os os set_inheritable9446983
Ref: f329446983
Ref: library/os os get_handle_inheritable9447109
Ref: f339447109
Ref: library/os os set_handle_inheritable9447278
Ref: f349447278
Node: Files and Directories9447448
Ref: library/os files-and-directories9447616
Ref: 2d729447616
Ref: library/os os-file-dir9447616
Ref: 2d069447616
Ref: library/os path-fd9447765
Ref: b789447765
Ref: library/os dir-fd9448703
Ref: 112e9448703
Ref: library/os follow-symlinks9449418
Ref: 112f9449418
Ref: library/os os access9450000
Ref: 11309450000
Ref: library/os os F_OK9452540
Ref: 2d739452540
Ref: library/os os R_OK9452558
Ref: 2d749452558
Ref: library/os os W_OK9452576
Ref: 2d759452576
Ref: library/os os X_OK9452594
Ref: 2d769452594
Ref: library/os os chdir9452784
Ref: 6109452784
Ref: library/os os chflags9453462
Ref: 11319453462
Ref: library/os os chmod9454551
Ref: 21b9454551
Ref: library/os os chown9456624
Ref: 11329456624
Ref: library/os os chroot9457634
Ref: 1b259457634
Ref: library/os os fchdir9457863
Ref: db79457863
Ref: library/os os getcwd9458268
Ref: 16a19458268
Ref: library/os os getcwdb9458362
Ref: aa09458362
Ref: library/os os lchflags9458670
Ref: 2d789458670
Ref: library/os os lchmod9459161
Ref: 21a9459161
Ref: library/os os lchown9459995
Ref: 2d799459995
Ref: library/os os link9460508
Ref: 11339460508
Ref: library/os os listdir9461295
Ref: 113e9461295
Ref: library/os os listdrives9462776
Ref: 4a09462776
Ref: library/os os listmounts9463409
Ref: 4a29463409
Ref: library/os os listvolumes9464250
Ref: 4a19464250
Ref: library/os os lstat9464970
Ref: 4a49464970
Ref: library/os os mkdir9466081
Ref: 21d9466081
Ref: library/os mkdir-modebits9466383
Ref: 2d7a9466383
Ref: library/os os makedirs9467545
Ref: 21e9467545
Ref: library/os os mkfifo9469252
Ref: dbe9469252
Ref: library/os os mknod9470155
Ref: dbf9470155
Ref: library/os os major9471048
Ref: 17229471048
Ref: library/os os minor9471219
Ref: 17239471219
Ref: library/os os makedev9471390
Ref: 17249471390
Ref: library/os os pathconf9471514
Ref: 113f9471514
Ref: library/os os pathconf_names9472612
Ref: 2d7c9472612
Ref: library/os os readlink9472936
Ref: 9299472936
Ref: library/os os remove9474418
Ref: 11349474418
Ref: library/os os removedirs9475353
Ref: 2d7d9475353
Ref: library/os os rename9476189
Ref: 11359476189
Ref: library/os os renames9477859
Ref: 2d7e9477859
Ref: library/os os replace9478648
Ref: 11369478648
Ref: library/os os rmdir9479530
Ref: 11379479530
Ref: library/os os scandir9480176
Ref: a6d9480176
Ref: library/os os scandir close9481936
Ref: ce29481936
Ref: library/os os DirEntry9483440
Ref: 49e9483440
Ref: library/os os DirEntry name9484614
Ref: 2d809484614
Ref: library/os os DirEntry path9484985
Ref: 178f9484985
Ref: library/os os DirEntry inode9485707
Ref: 17e99485707
Ref: library/os os DirEntry is_dir9486066
Ref: 2d7f9486066
Ref: library/os os DirEntry is_file9487501
Ref: db29487501
Ref: library/os os DirEntry is_symlink9488224
Ref: 2d819488224
Ref: library/os os DirEntry is_junction9489075
Ref: 49f9489075
Ref: library/os os DirEntry stat9489510
Ref: 180a9489510
Ref: library/os os stat9491252
Ref: 4a39491252
Ref: library/os os stat_result9493840
Ref: 15109493840
Ref: library/os os stat_result st_mode9494090
Ref: a179494090
Ref: library/os os stat_result st_ino9494185
Ref: 2d829494185
Ref: library/os os stat_result st_dev9494434
Ref: 2d839494434
Ref: library/os os stat_result st_nlink9494526
Ref: 2d849494526
Ref: library/os os stat_result st_uid9494589
Ref: 2d859494589
Ref: library/os os stat_result st_gid9494663
Ref: 2d869494663
Ref: library/os os stat_result st_size9494738
Ref: 2d879494738
Ref: library/os os stat_result st_atime9494992
Ref: 2d889494992
Ref: library/os os stat_result st_mtime9495082
Ref: 2c139495082
Ref: library/os os stat_result st_ctime9495186
Ref: 2d899495186
Ref: library/os os stat_result st_atime_ns9495556
Ref: 2d8a9495556
Ref: library/os os stat_result st_mtime_ns9495710
Ref: 2d8b9495710
Ref: library/os os stat_result st_ctime_ns9495878
Ref: 2d8c9495878
Ref: library/os os stat_result st_birthtime9496318
Ref: 2d8d9496318
Ref: library/os os stat_result st_birthtime_ns9496593
Ref: 2d8e9496593
Ref: library/os os stat_result st_blocks9498130
Ref: 2d8f9498130
Ref: library/os os stat_result st_blksize9498304
Ref: 2d909498304
Ref: library/os os stat_result st_rdev9498506
Ref: 16159498506
Ref: library/os os stat_result st_flags9498581
Ref: 2d919498581
Ref: library/os os stat_result st_gen9498806
Ref: 2d929498806
Ref: library/os os stat_result st_fstype9498956
Ref: b809498956
Ref: library/os os stat_result st_rsize9499163
Ref: 2d939499163
Ref: library/os os stat_result st_creator9499227
Ref: 2d949499227
Ref: library/os os stat_result st_type9499291
Ref: 2d959499291
Ref: library/os os stat_result st_file_attributes9499413
Ref: e6b9499413
Ref: library/os os stat_result st_reparse_tag9499793
Ref: a189499793
Ref: library/os os statvfs9502150
Ref: 11409502150
Ref: library/os os supports_dir_fd9504195
Ref: 113b9504195
Ref: library/os os supports_effective_ids9505350
Ref: 11429505350
Ref: library/os os supports_fd9506086
Ref: 11419506086
Ref: library/os os supports_follow_symlinks9506905
Ref: 113c9506905
Ref: library/os os symlink9508036
Ref: 11389508036
Ref: library/os os sync9509960
Ref: 11569509960
Ref: library/os os truncate9510094
Ref: e6f9510094
Ref: library/os os unlink9510618
Ref: 11399510618
Ref: library/os os utime9511148
Ref: 113a9511148
Ref: library/os os walk9512998
Ref: 4ac9512998
Ref: library/os os fwalk9518240
Ref: b779518240
Ref: library/os os memfd_create9520866
Ref: a169520866
Ref: library/os os MFD_CLOEXEC9521725
Ref: 2d969521725
Ref: library/os os MFD_ALLOW_SEALING9521750
Ref: 2d979521750
Ref: library/os os MFD_HUGETLB9521781
Ref: 2d989521781
Ref: library/os os MFD_HUGE_SHIFT9521806
Ref: 2d999521806
Ref: library/os os MFD_HUGE_MASK9521834
Ref: 2d9a9521834
Ref: library/os os MFD_HUGE_64KB9521861
Ref: 2d9b9521861
Ref: library/os os MFD_HUGE_512KB9521888
Ref: 2d9c9521888
Ref: library/os os MFD_HUGE_1MB9521916
Ref: 2d9d9521916
Ref: library/os os MFD_HUGE_2MB9521942
Ref: 2d9e9521942
Ref: library/os os MFD_HUGE_8MB9521968
Ref: 2d9f9521968
Ref: library/os os MFD_HUGE_16MB9521994
Ref: 2da09521994
Ref: library/os os MFD_HUGE_32MB9522021
Ref: 2da19522021
Ref: library/os os MFD_HUGE_256MB9522048
Ref: 2da29522048
Ref: library/os os MFD_HUGE_512MB9522076
Ref: 2da39522076
Ref: library/os os MFD_HUGE_1GB9522104
Ref: 2da49522104
Ref: library/os os MFD_HUGE_2GB9522130
Ref: 2da59522130
Ref: library/os os MFD_HUGE_16GB9522156
Ref: 2da69522156
Ref: library/os os eventfd9522409
Ref: 81e9522409
Ref: library/os os eventfd_read9524422
Ref: 2da89524422
Ref: library/os os eventfd_write9524706
Ref: 2da99524706
Ref: library/os os EFD_CLOEXEC9525002
Ref: 18fe9525002
Ref: library/os os EFD_NONBLOCK9525187
Ref: 18ff9525187
Ref: library/os os EFD_SEMAPHORE9525389
Ref: 19009525389
Ref: Files and Directories-Footnote-19525757
Ref: Files and Directories-Footnote-29525803
Ref: Files and Directories-Footnote-39525845
Ref: Files and Directories-Footnote-49525910
Ref: Files and Directories-Footnote-59525990
Ref: Files and Directories-Footnote-69526072
Ref: Files and Directories-Footnote-79526161
Ref: Files and Directories-Footnote-89526250
Ref: Files and Directories-Footnote-99526308
Node: Timer File Descriptors9526355
Ref: library/os os-timerfd9526469
Ref: 1539526469
Ref: library/os timer-file-descriptors9526469
Ref: 2daa9526469
Ref: library/os os timerfd_create9526683
Ref: 2119526683
Ref: library/os os timerfd_settime9529345
Ref: 2129529345
Ref: library/os os timerfd_settime_ns9532060
Ref: 2139532060
Ref: library/os os timerfd_gettime9532408
Ref: 2149532408
Ref: library/os os timerfd_gettime_ns9532995
Ref: 2159532995
Ref: library/os os TFD_NONBLOCK9533220
Ref: 2169533220
Ref: library/os os TFD_CLOEXEC9533581
Ref: 2179533581
Ref: library/os os TFD_TIMER_ABSTIME9533866
Ref: 2189533866
Ref: library/os os TFD_TIMER_CANCEL_ON_SET9534253
Ref: 2199534253
Ref: Timer File Descriptors-Footnote-19534664
Ref: Timer File Descriptors-Footnote-29534718
Ref: Timer File Descriptors-Footnote-39534772
Ref: Timer File Descriptors-Footnote-49534827
Ref: Timer File Descriptors-Footnote-59534879
Ref: Timer File Descriptors-Footnote-69534932
Ref: Timer File Descriptors-Footnote-79534976
Node: Linux extended attributes9535031
Ref: library/os linux-extended-attributes9535145
Ref: 2dac9535145
Ref: library/os os getxattr9535291
Ref: 11489535291
Ref: library/os os listxattr9535952
Ref: 11499535952
Ref: library/os os removexattr9536555
Ref: 114a9536555
Ref: library/os os setxattr9537247
Ref: 114b9537247
Ref: library/os os XATTR_SIZE_MAX9538479
Ref: 2daf9538479
Ref: library/os os XATTR_CREATE9538615
Ref: 2dae9538615
Ref: library/os os XATTR_REPLACE9538787
Ref: 2dad9538787
Node: Process Management9538970
Ref: library/os os-process9539138
Ref: 2db09539138
Ref: library/os process-management9539138
Ref: 2db19539138
Ref: library/os os abort9539753
Ref: 2db39539753
Ref: library/os os add_dll_directory9540129
Ref: 9f59540129
Ref: library/os os execl9541293
Ref: 2db29541293
Ref: library/os os execle9541340
Ref: 2db49541340
Ref: library/os os execlp9541393
Ref: 2db59541393
Ref: library/os os execlpe9541441
Ref: 2db69541441
Ref: library/os os execv9541495
Ref: 2d169541495
Ref: library/os os execve9541531
Ref: 113d9541531
Ref: library/os os execvp9541573
Ref: 2db79541573
Ref: library/os os execvpe9541610
Ref: 2db89541610
Ref: library/os os _exit9544838
Ref: 24519544838
Ref: library/os os EX_OK9545584
Ref: 2dba9545584
Ref: library/os os EX_USAGE9545818
Ref: 2dbb9545818
Ref: library/os os EX_DATAERR9546010
Ref: 2dbc9546010
Ref: library/os os EX_NOINPUT9546141
Ref: 2dbd9546141
Ref: library/os os EX_NOUSER9546296
Ref: 2dbe9546296
Ref: library/os os EX_NOHOST9546428
Ref: 2dbf9546428
Ref: library/os os EX_UNAVAILABLE9546560
Ref: 2dc09546560
Ref: library/os os EX_SOFTWARE9546705
Ref: 2dc19546705
Ref: library/os os EX_OSERR9546848
Ref: 2dc29546848
Ref: library/os os EX_OSFILE9547040
Ref: 2dc39547040
Ref: library/os os EX_CANTCREAT9547231
Ref: 2dc49547231
Ref: library/os os EX_IOERR9547390
Ref: 2dc59547390
Ref: library/os os EX_TEMPFAIL9547547
Ref: 2dc69547547
Ref: library/os os EX_PROTOCOL9547831
Ref: 2dc79547831
Ref: library/os os EX_NOPERM9548004
Ref: 2dc89548004
Ref: library/os os EX_CONFIG9548220
Ref: 2dc99548220
Ref: library/os os EX_NOTFOUND9548373
Ref: 2dca9548373
Ref: library/os os fork9548520
Ref: 1979548520
Ref: library/os os forkpty9550526
Ref: 1989550526
Ref: library/os os kill9551673
Ref: 13b49551673
Ref: library/os os killpg9552548
Ref: 1b669552548
Ref: library/os os nice9552806
Ref: 11459552806
Ref: library/os os pidfd_open9552981
Ref: 47d9552981
Ref: library/os os PIDFD_NONBLOCK9553392
Ref: 49d9553392
Ref: library/os os plock9553843
Ref: 2dcb9553843
Ref: library/os os popen9554068
Ref: a969554068
Ref: library/os os posix_spawn9555986
Ref: 2209555986
Ref: library/os os POSIX_SPAWN_OPEN9557083
Ref: 2dcc9557083
Ref: library/os os POSIX_SPAWN_CLOSE9557256
Ref: 2dcd9557256
Ref: library/os os POSIX_SPAWN_DUP29557379
Ref: 2dce9557379
Ref: library/os os POSIX_SPAWN_CLOSEFROM9557517
Ref: 2219557517
Ref: library/os os posix_spawnp9560423
Ref: 15b49560423
Ref: library/os os register_at_fork9561182
Ref: 3009561182
Ref: library/os os spawnl9562631
Ref: 18429562631
Ref: library/os os spawnle9562673
Ref: 2dcf9562673
Ref: library/os os spawnlp9562721
Ref: 2dd09562721
Ref: library/os os spawnlpe9562764
Ref: 2dd19562764
Ref: library/os os spawnv9562813
Ref: 2dd29562813
Ref: library/os os spawnve9562856
Ref: 2dd39562856
Ref: library/os os spawnvp9562905
Ref: 2dd49562905
Ref: library/os os spawnvpe9562949
Ref: 2dd59562949
Ref: library/os os P_NOWAIT9566682
Ref: 2dd69566682
Ref: library/os os P_NOWAITO9566704
Ref: 2dd89566704
Ref: library/os os P_WAIT9567048
Ref: 2dd79567048
Ref: library/os os P_DETACH9567463
Ref: 2dd99567463
Ref: library/os os P_OVERLAY9567485
Ref: 2dda9567485
Ref: library/os os startfile9567970
Ref: 1a299567970
Ref: library/os os system9570554
Ref: 14ac9570554
Ref: library/os os times9572299
Ref: 11599572299
Ref: library/os os wait9573307
Ref: dc69573307
Ref: library/os os waitid9574217
Ref: dc79574217
Ref: library/os os waitpid9575654
Ref: dc89575654
Ref: library/os os wait39578014
Ref: dc49578014
Ref: library/os os wait49578636
Ref: dc59578636
Ref: library/os os P_PID9579216
Ref: 2ddb9579216
Ref: library/os os P_PGID9579235
Ref: 2ddc9579235
Ref: library/os os P_ALL9579255
Ref: 2ddd9579255
Ref: library/os os P_PIDFD9579274
Ref: 9239579274
Ref: library/os os WCONTINUED9580007
Ref: 2de09580007
Ref: library/os os WEXITED9580356
Ref: 2dde9580356
Ref: library/os os WSTOPPED9580723
Ref: 2ddf9580723
Ref: library/os os WUNTRACED9581063
Ref: 2de59581063
Ref: library/os os WNOHANG9581469
Ref: 2de19581469
Ref: library/os os WNOWAIT9581766
Ref: 2de29581766
Ref: library/os os CLD_EXITED9582130
Ref: 2de49582130
Ref: library/os os CLD_KILLED9582154
Ref: 9219582154
Ref: library/os os CLD_DUMPED9582178
Ref: 2de69582178
Ref: library/os os CLD_TRAPPED9582202
Ref: 2de79582202
Ref: library/os os CLD_STOPPED9582227
Ref: 9229582227
Ref: library/os os CLD_CONTINUED9582252
Ref: 2de89582252
Ref: library/os os waitstatus_to_exitcode9582573
Ref: 9269582573
Ref: library/os os WCOREDUMP9584079
Ref: 2def9584079
Ref: library/os os WIFCONTINUED9584383
Ref: 2df09584383
Ref: library/os os WIFSTOPPED9584733
Ref: 2ded9584733
Ref: library/os os WIFSIGNALED9585153
Ref: 2deb9585153
Ref: library/os os WIFEXITED9585365
Ref: 2de99585365
Ref: library/os os WEXITSTATUS9585666
Ref: 2dea9585666
Ref: library/os os WSTOPSIG9585900
Ref: 2dee9585900
Ref: library/os os WTERMSIG9586152
Ref: 2dec9586152
Ref: Process Management-Footnote-19586464
Ref: Process Management-Footnote-29586536
Ref: Process Management-Footnote-39586579
Ref: Process Management-Footnote-49586629
Ref: Process Management-Footnote-59586675
Ref: Process Management-Footnote-69586720
Ref: Process Management-Footnote-79586772
Ref: Process Management-Footnote-89586881
Ref: Process Management-Footnote-99586923
Node: Interface to the scheduler9586969
Ref: library/os interface-to-the-scheduler9587148
Ref: 2df29587148
Ref: library/os os-scheduling-policy9587535
Ref: 2df39587535
Ref: library/os os SCHED_OTHER9587535
Ref: 2df49587535
Ref: library/os os SCHED_BATCH9587598
Ref: 2df59587598
Ref: library/os os SCHED_IDLE9587747
Ref: 2df69587747
Ref: library/os os SCHED_SPORADIC9587841
Ref: 2df79587841
Ref: library/os os SCHED_FIFO9587924
Ref: 2df89587924
Ref: library/os os SCHED_RR9587995
Ref: 2df99587995
Ref: library/os os SCHED_RESET_ON_FORK9588057
Ref: 2dfa9588057
Ref: library/os os sched_param9588279
Ref: 16a89588279
Ref: library/os os sched_param sched_priority9588574
Ref: 2dfb9588574
Ref: library/os os sched_get_priority_min9588670
Ref: 114d9588670
Ref: library/os os sched_get_priority_max9588835
Ref: 114c9588835
Ref: library/os os sched_setscheduler9589000
Ref: 11549589000
Ref: library/os os sched_getscheduler9589289
Ref: 11509589289
Ref: library/os os sched_setparam9589514
Ref: 11539589514
Ref: library/os os sched_getparam9589731
Ref: 114f9589731
Ref: library/os os sched_rr_get_interval9589934
Ref: 11519589934
Ref: library/os os sched_yield9590109
Ref: 11559590109
Ref: library/os os sched_setaffinity9590226
Ref: 11529590226
Ref: library/os os sched_getaffinity9590492
Ref: 114e9590492
Ref: Interface to the scheduler-Footnote-19590820
Node: Miscellaneous System Information9590871
Ref: library/os miscellaneous-system-information9591049
Ref: 2dfc9591049
Ref: library/os os-path9591049
Ref: 2dfd9591049
Ref: library/os os confstr9591136
Ref: 166f9591136
Ref: library/os os confstr_names9592175
Ref: 2dfe9592175
Ref: library/os os cpu_count9592468
Ref: 1c59592468
Ref: library/os os getloadavg9592956
Ref: 16ef9592956
Ref: library/os os process_cpu_count9593210
Ref: 1c49593210
Ref: library/os os sysconf9593812
Ref: 16709593812
Ref: library/os os sysconf_names9594236
Ref: 2dff9594236
Ref: library/os os curdir9594792
Ref: 29ac9594792
Ref: library/os os pardir9594993
Ref: 2d7b9594993
Ref: library/os os sep9595194
Ref: 66d9595194
Ref: library/os os altsep9595606
Ref: 66e9595606
Ref: library/os os extsep9595905
Ref: 2e009595905
Ref: library/os os pathsep9596092
Ref: 1eec9596092
Ref: library/os os defpath9596336
Ref: 1b929596336
Ref: library/os os linesep9596545
Ref: 23349596545
Ref: library/os os devnull9596958
Ref: 1bc39596958
Ref: library/os os RTLD_LAZY9597132
Ref: 115c9597132
Ref: library/os os RTLD_NOW9597155
Ref: 115d9597155
Ref: library/os os RTLD_GLOBAL9597177
Ref: 115e9597177
Ref: library/os os RTLD_LOCAL9597202
Ref: 115f9597202
Ref: library/os os RTLD_NODELETE9597226
Ref: 11609597226
Ref: library/os os RTLD_NOLOAD9597253
Ref: 11619597253
Ref: library/os os RTLD_DEEPBIND9597278
Ref: 11629597278
Ref: Miscellaneous System Information-Footnote-19597564
Node: Random numbers<2>9597610
Ref: library/os random-numbers9597753
Ref: 2e019597753
Ref: library/os os getrandom9597804
Ref: ce39597804
Ref: library/os os urandom9598634
Ref: 5269598634
Ref: library/os os GRND_NONBLOCK9600699
Ref: 2e039600699
Ref: library/os os GRND_RANDOM9601168
Ref: 2e029601168
Ref: Random numbers<2>-Footnote-19601389
Ref: Random numbers<2>-Footnote-29601452
Node: io — Core tools for working with streams9601494
Ref: library/io doc9601708
Ref: 2e049601708
Ref: library/io io-core-tools-for-working-with-streams9601708
Ref: 2e059601708
Ref: library/io module-io9601708
Ref: 7f9601708
Ref: library/io translation-repo9601708
Ref: 2e069601708
Ref: io — Core tools for working with streams-Footnote-19602084
Node: Overview<2>9602146
Ref: library/io io-overview9602258
Ref: 23329602258
Ref: library/io overview9602258
Ref: 2e079602258
Node: Text I/O9603502
Ref: library/io text-i-o9603577
Ref: 2e089603577
Node: Binary I/O9604268
Ref: library/io binary-i-o9604359
Ref: 2e099604359
Node: Raw I/O9605229
Ref: library/io raw-i-o9605303
Ref: 2e0a9605303
Node: Text Encoding9605757
Ref: library/io io-text-encoding9605905
Ref: 7c19605905
Ref: library/io text-encoding9605905
Ref: 2e0b9605905
Ref: Text Encoding-Footnote-19607078
Node: Opt-in EncodingWarning9607120
Ref: library/io io-encoding-warning9607192
Ref: 1ef89607192
Ref: library/io opt-in-encodingwarning9607192
Ref: 2e0c9607192
Ref: Opt-in EncodingWarning-Footnote-19608010
Node: High-level Module Interface9608052
Ref: library/io high-level-module-interface9608204
Ref: 2e0d9608204
Ref: library/io io DEFAULT_BUFFER_SIZE9608279
Ref: 17d79608279
Ref: library/io io open9608514
Ref: 5209608514
Ref: library/io io open_code9608929
Ref: 15a79608929
Ref: library/io io text_encoding9609592
Ref: 17d69609592
Ref: library/io io BlockingIOError9610719
Ref: 2e0e9610719
Ref: library/io io UnsupportedOperation9610844
Ref: 1b289610844
Node: Class hierarchy9611191
Ref: library/io class-hierarchy9611344
Ref: 2e0f9611344
Node: I/O Base Classes9616022
Ref: library/io i-o-base-classes9616111
Ref: 2e109616111
Ref: library/io io IOBase9616164
Ref: 1f59616164
Ref: library/io io IOBase close9617977
Ref: 1f69617977
Ref: library/io io IOBase closed9618387
Ref: 1bbd9618387
Ref: library/io io IOBase fileno9618462
Ref: 15f59618462
Ref: library/io io IOBase flush9618683
Ref: 2db99618683
Ref: library/io io IOBase isatty9618843
Ref: 1e219618843
Ref: library/io io IOBase readable9618983
Ref: 13fa9618983
Ref: library/io io IOBase readline9619145
Ref: 13739619145
Ref: library/io io IOBase readlines9619517
Ref: 24e79619517
Ref: library/io io IOBase seek9620081
Ref: 12d39620081
Ref: library/io io IOBase seekable9621061
Ref: 13fc9621061
Ref: library/io io IOBase tell9621294
Ref: 13f99621294
Ref: library/io io IOBase truncate9621367
Ref: 135a9621367
Ref: library/io io IOBase writable9621945
Ref: 13fb9621945
Ref: library/io io IOBase writelines9622146
Ref: 15c59622146
Ref: library/io io IOBase __del__9622369
Ref: 2e119622369
Ref: library/io io RawIOBase9622580
Ref: 11149622580
Ref: library/io io RawIOBase read9623079
Ref: e4e9623079
Ref: library/io io RawIOBase readall9623763
Ref: 2e129623763
Ref: library/io io RawIOBase readinto9623919
Ref: e4f9623919
Ref: library/io io RawIOBase write9624260
Ref: 13f89624260
Ref: library/io io BufferedIOBase9624899
Ref: 6979624899
Ref: library/io io BufferedIOBase raw9626092
Ref: 13fd9626092
Ref: library/io io BufferedIOBase detach9626351
Ref: 2b659626351
Ref: library/io io BufferedIOBase read9626787
Ref: 13729626787
Ref: library/io io BufferedIOBase read19628067
Ref: 2b549628067
Ref: library/io io BufferedIOBase readinto9628650
Ref: 2e139628650
Ref: library/io io BufferedIOBase readinto19629185
Ref: e4d9629185
Ref: library/io io BufferedIOBase write9629683
Ref: d029629683
Ref: I/O Base Classes-Footnote-19630540
Ref: I/O Base Classes-Footnote-29630582
Node: Raw File I/O9630624
Ref: library/io raw-file-i-o9630738
Ref: 2e149630738
Ref: library/io io FileIO9630785
Ref: 13599630785
Ref: library/io io FileIO mode9633079
Ref: 2e159633079
Ref: library/io io FileIO name9633154
Ref: 2b6f9633154
Node: Buffered Streams9633299
Ref: library/io buffered-streams9633408
Ref: 2e169633408
Ref: library/io io BytesIO9633554
Ref: ed89633554
Ref: library/io io BytesIO getbuffer9634029
Ref: 12369634029
Ref: library/io io BytesIO getvalue9634592
Ref: 2b529634592
Ref: library/io io BytesIO read19634714
Ref: 2e179634714
Ref: library/io io BytesIO readinto19634892
Ref: 2e189634892
Ref: library/io io BufferedReader9635033
Ref: 12539635033
Ref: library/io io BufferedReader peek9635854
Ref: 2e199635854
Ref: library/io io BufferedReader read9636154
Ref: 2e1a9636154
Ref: library/io io BufferedReader read19636293
Ref: 2e1b9636293
Ref: library/io io BufferedWriter9636506
Ref: 13fe9636506
Ref: library/io io BufferedWriter flush9637590
Ref: 2e1c9637590
Ref: library/io io BufferedWriter write9637775
Ref: 2e1d9637775
Ref: library/io io BufferedRandom9638133
Ref: 13ff9638133
Ref: library/io io BufferedRWPair9638823
Ref: 14009638823
Node: Text I/O<2>9639749
Ref: library/io id19639837
Ref: 2e1e9639837
Ref: library/io io TextIOBase9639876
Ref: 6989639876
Ref: library/io io TextIOBase encoding9640186
Ref: 2e1f9640186
Ref: library/io io TextIOBase errors9640346
Ref: 13589640346
Ref: library/io io TextIOBase newlines9640430
Ref: 2e209640430
Ref: library/io io TextIOBase buffer9640674
Ref: 12ea9640674
Ref: library/io io TextIOBase detach9640960
Ref: 15cc9640960
Ref: library/io io TextIOBase read9641449
Ref: 1e249641449
Ref: library/io io TextIOBase readline9641657
Ref: 1e5e9641657
Ref: library/io io TextIOBase seek9641927
Ref: 2e219641927
Ref: library/io io TextIOBase tell9642900
Ref: 2e229642900
Ref: library/io io TextIOBase write9643104
Ref: 1e139643104
Ref: library/io io TextIOWrapper9643236
Ref: 7bf9643236
Ref: library/io io TextIOWrapper line_buffering9647082
Ref: 2e239647082
Ref: library/io io TextIOWrapper write_through9647164
Ref: 2e249647164
Ref: library/io io TextIOWrapper reconfigure9647324
Ref: b649647324
Ref: library/io io TextIOWrapper seek9648214
Ref: 2e259648214
Ref: library/io io TextIOWrapper tell9649135
Ref: 15f99649135
Ref: library/io io StringIO9649358
Ref: f5e9649358
Ref: library/io io StringIO getvalue9650517
Ref: 2e269650517
Ref: library/io io IncrementalNewlineDecoder9651172
Ref: 17d89651172
Node: Performance<3>9651359
Ref: library/io performance9651476
Ref: 2e279651476
Node: Binary I/O<2>9651725
Ref: library/io id29651809
Ref: 2e289651809
Node: Text I/O<3>9652461
Ref: library/io id39652572
Ref: 2e299652572
Node: Multi-threading<3>9653135
Ref: library/io multi-threading9653243
Ref: 2e2a9653243
Ref: Multi-threading<3>-Footnote-19653817
Node: Reentrancy9653861
Ref: library/io reentrancy9653949
Ref: 2e2b9653949
Node: time — Time access and conversions9654742
Ref: library/time doc9654947
Ref: 2e2c9654947
Ref: library/time module-time9654947
Ref: ee9654947
Ref: library/time time-time-access-and-conversions9654947
Ref: 2e2d9654947
Ref: library/time translation-repo9654947
Ref: 2e2e9654947
Ref: library/time epoch9655649
Ref: 2c129655649
Ref: time — Time access and conversions-Footnote-19660093
Ref: time — Time access and conversions-Footnote-29660143
Ref: time — Time access and conversions-Footnote-39660208
Node: Functions<5>9660266
Ref: library/time functions9660378
Ref: 2e319660378
Ref: library/time time-functions9660378
Ref: 2e329660378
Ref: library/time time asctime9660417
Ref: 122c9660417
Ref: library/time time pthread_getcpuclockid9661075
Ref: bb09661075
Ref: library/time time clock_getres9661692
Ref: 11a19661692
Ref: library/time time clock_gettime9661969
Ref: 11a29661969
Ref: library/time time clock_gettime_ns9662351
Ref: afa9662351
Ref: library/time time clock_settime9662554
Ref: 11a39662554
Ref: library/time time clock_settime_ns9662948
Ref: afb9662948
Ref: library/time time ctime9663176
Ref: 26129663176
Ref: library/time time get_clock_info9663750
Ref: 11a09663750
Ref: library/time time gmtime9664887
Ref: 12059664887
Ref: library/time time localtime9665373
Ref: 15489665373
Ref: library/time time mktime9666011
Ref: 122d9666011
Ref: library/time time monotonic9666721
Ref: 2539666721
Ref: library/time time monotonic_ns9667811
Ref: afc9667811
Ref: library/time time perf_counter9667955
Ref: a979667955
Ref: library/time time perf_counter_ns9668890
Ref: afd9668890
Ref: library/time time process_time9669045
Ref: a989669045
Ref: library/time time process_time_ns9669574
Ref: afe9669574
Ref: library/time time sleep9669729
Ref: 6a09669729
Ref: library/time time strftime9671828
Ref: 122e9671828
Ref: library/time leap-second9679261
Ref: 2e349679261
Ref: library/time time strptime9680465
Ref: 147b9680465
Ref: library/time time struct_time9682168
Ref: d119682168
Ref: library/time time struct_time tm_year9682812
Ref: 15479682812
Ref: library/time time struct_time tm_mon9683076
Ref: 2e359683076
Ref: library/time time struct_time tm_mday9683336
Ref: 2e369683336
Ref: library/time time struct_time tm_hour9683595
Ref: 2e379683595
Ref: library/time time struct_time tm_min9683853
Ref: 2e389683853
Ref: library/time time struct_time tm_sec9684112
Ref: 2e399684112
Ref: library/time time struct_time tm_wday9684588
Ref: 2e3a9684588
Ref: library/time time struct_time tm_yday9684859
Ref: 2e3b9684859
Ref: library/time time struct_time tm_isdst9685120
Ref: 26239685120
Ref: library/time time struct_time tm_zone9685386
Ref: 2e309685386
Ref: library/time time struct_time tm_gmtoff9685663
Ref: 2e2f9685663
Ref: library/time time time9686335
Ref: 2549686335
Ref: library/time time time_ns9687902
Ref: aff9687902
Ref: library/time time thread_time9688091
Ref: 9409688091
Ref: library/time time thread_time_ns9688760
Ref: baf9688760
Ref: library/time time tzset9688913
Ref: 2e3c9688913
Ref: Functions<5>-Footnote-19692820
Ref: Functions<5>-Footnote-29692881
Ref: Functions<5>-Footnote-39692980
Ref: Functions<5>-Footnote-49693022
Ref: Functions<5>-Footnote-59693803
Ref: Functions<5>-Footnote-69694584
Ref: Functions<5>-Footnote-79694634
Ref: Functions<5>-Footnote-89694693
Ref: Functions<5>-Footnote-99695474
Ref: Functions<5>-Footnote-109695522
Ref: Functions<5>-Footnote-119695573
Ref: Functions<5>-Footnote-129695622
Node: Clock ID Constants9695669
Ref: library/time clock-id-constants9695808
Ref: 2e3d9695808
Ref: library/time time-clock-id-constants9695808
Ref: 2dab9695808
Ref: library/time time CLOCK_BOOTTIME9695970
Ref: bac9695970
Ref: library/time time CLOCK_HIGHRES9696448
Ref: 2e3e9696448
Ref: library/time time CLOCK_MONOTONIC9696776
Ref: 69c9696776
Ref: library/time time CLOCK_MONOTONIC_RAW9696980
Ref: 2e3f9696980
Ref: library/time time CLOCK_MONOTONIC_RAW_APPROX9697249
Ref: 2e409697249
Ref: library/time time CLOCK_PROCESS_CPUTIME_ID9697511
Ref: 2e419697511
Ref: library/time time CLOCK_PROF9697673
Ref: bad9697673
Ref: library/time time CLOCK_TAI9697846
Ref: 1afe9697846
Ref: library/time time CLOCK_THREAD_CPUTIME_ID9698141
Ref: 2e429698141
Ref: library/time time CLOCK_UPTIME9698286
Ref: bae9698286
Ref: library/time time CLOCK_UPTIME_RAW9698569
Ref: a509698569
Ref: library/time time CLOCK_UPTIME_RAW_APPROX9698868
Ref: 2e439698868
Ref: library/time time CLOCK_REALTIME9699217
Ref: 69d9699217
Ref: Clock ID Constants-Footnote-19699474
Node: Timezone Constants9699601
Ref: library/time time-timezone-constants9699719
Ref: 2e449699719
Ref: library/time timezone-constants9699719
Ref: 2e459699719
Ref: library/time time altzone9699776
Ref: 2e469699776
Ref: library/time time daylight9700064
Ref: 2e479700064
Ref: library/time time timezone9700150
Ref: 2e489700150
Ref: library/time time tzname9700348
Ref: 2e499700348
Node: logging — Logging facility for Python9701550
Ref: library/logging doc9701753
Ref: 2e4a9701753
Ref: library/logging logging-logging-facility-for-python9701753
Ref: 2e4b9701753
Ref: library/logging module-logging9701753
Ref: 879701753
Ref: library/logging translation-repo9701753
Ref: 2e4c9701753
Ref: logging — Logging facility for Python-Footnote-19705245
Node: Logger Objects9705322
Ref: library/logging logger9705435
Ref: 2e4d9705435
Ref: library/logging logger-objects9705435
Ref: 2e4e9705435
Ref: library/logging logging Logger9706589
Ref: b6a9706589
Ref: library/logging logging Logger name9706616
Ref: 2e4f9706616
Ref: library/logging logging Logger level9706843
Ref: 2e509706843
Ref: library/logging logging Logger parent9707136
Ref: 2e519707136
Ref: library/logging logging Logger propagate9707397
Ref: 14e49707397
Ref: library/logging logging Logger handlers9709466
Ref: 2e529709466
Ref: library/logging logging Logger disabled9709843
Ref: 2e559709843
Ref: library/logging logging Logger setLevel9710115
Ref: 14e29710115
Ref: library/logging logging Logger isEnabledFor9712094
Ref: 133f9712094
Ref: library/logging logging Logger getEffectiveLevel9712437
Ref: 2e579712437
Ref: library/logging logging Logger getChild9712938
Ref: 133d9712938
Ref: library/logging logging Logger getChildren9713439
Ref: 18f79713439
Ref: library/logging logging Logger debug9714009
Ref: e5d9714009
Ref: library/logging logging Logger info9719465
Ref: 2e599719465
Ref: library/logging logging Logger warning9719650
Ref: 18139719650
Ref: library/logging logging Logger error9720062
Ref: 2e5b9720062
Ref: library/logging logging Logger critical9720249
Ref: e5c9720249
Ref: library/logging logging Logger log9720453
Ref: e5a9720453
Ref: library/logging logging Logger exception9720649
Ref: e5b9720649
Ref: library/logging logging Logger addFilter9720970
Ref: 2e5c9720970
Ref: library/logging logging Logger removeFilter9721069
Ref: 2e5d9721069
Ref: library/logging logging Logger filter9721176
Ref: 2e5e9721176
Ref: library/logging logging Logger addHandler9721613
Ref: 2e539721613
Ref: library/logging logging Logger removeHandler9721710
Ref: 2e549721710
Ref: library/logging logging Logger findCaller9721815
Ref: 2e5f9721815
Ref: library/logging logging Logger handle9722617
Ref: 2e609722617
Ref: library/logging logging Logger makeRecord9723016
Ref: 2e619723016
Ref: library/logging logging Logger hasHandlers9723279
Ref: 2e629723279
Node: Logging Levels9723900
Ref: library/logging levels9724037
Ref: 65d9724037
Ref: library/logging logging-levels9724037
Ref: 2e639724037
Ref: library/logging logging NOTSET9724710
Ref: 2e569724710
Ref: library/logging logging DEBUG9725320
Ref: 1e959725320
Ref: library/logging logging INFO9725655
Ref: 1e969725655
Ref: library/logging logging WARNING9725902
Ref: 1e979725902
Ref: library/logging logging ERROR9726411
Ref: 1e989726411
Ref: library/logging logging CRITICAL9726727
Ref: 1e999726727
Node: Handler Objects9726999
Ref: library/logging handler9727139
Ref: 2e649727139
Ref: library/logging handler-objects9727139
Ref: 2e659727139
Ref: library/logging logging Handler9727459
Ref: 14e59727459
Ref: library/logging logging Handler __init__9727487
Ref: 2e669727487
Ref: library/logging logging Handler createLock9727775
Ref: 2e679727775
Ref: library/logging logging Handler acquire9727963
Ref: 2e689727963
Ref: library/logging logging Handler release9728077
Ref: 2e699728077
Ref: library/logging logging Handler setLevel9728179
Ref: 2e6a9728179
Ref: library/logging logging Handler setFormatter9728763
Ref: 2e6b9728763
Ref: library/logging logging Handler addFilter9728944
Ref: 2e6c9728944
Ref: library/logging logging Handler removeFilter9729044
Ref: 2e6d9729044
Ref: library/logging logging Handler filter9729152
Ref: 2e6e9729152
Ref: library/logging logging Handler flush9729551
Ref: 2e6f9729551
Ref: library/logging logging Handler close9729719
Ref: 2e709729719
Ref: library/logging logging Handler handle9730056
Ref: 2e719730056
Ref: library/logging logging Handler handleError9730334
Ref: 2e729730334
Ref: library/logging logging Handler format9731129
Ref: 2e749731129
Ref: library/logging logging Handler emit9731297
Ref: 2e739731297
Node: Formatter Objects9732829
Ref: library/logging formatter-objects9732969
Ref: 2e759732969
Ref: library/logging id19732969
Ref: 2e769732969
Ref: library/logging logging Formatter9733024
Ref: 14e69733024
Ref: library/logging logging Formatter format9735187
Ref: 2e799735187
Ref: library/logging logging Formatter formatTime9736657
Ref: 2e779736657
Ref: library/logging logging Formatter formatException9739037
Ref: 2e7a9739037
Ref: library/logging logging Formatter formatStack9739375
Ref: 2e7b9739375
Ref: library/logging logging BufferingFormatter9739667
Ref: 2e7c9739667
Ref: library/logging logging BufferingFormatter formatHeader9740085
Ref: 2e7d9740085
Ref: library/logging logging BufferingFormatter formatFooter9740399
Ref: 2e7e9740399
Ref: library/logging logging BufferingFormatter format9740704
Ref: 2e7f9740704
Node: Filter Objects9741035
Ref: library/logging filter9741177
Ref: 2e809741177
Ref: library/logging filter-objects9741177
Ref: 2e819741177
Ref: library/logging logging Filter9741691
Ref: 12409741691
Ref: library/logging logging Filter filter9741975
Ref: 2e829741975
Node: LogRecord Objects9744375
Ref: library/logging log-record9744520
Ref: 2e859744520
Ref: library/logging logrecord-objects9744520
Ref: 2e869744520
Ref: library/logging logging LogRecord9744814
Ref: 10219744814
Ref: library/logging logging LogRecord getMessage9747369
Ref: 2e899747369
Node: LogRecord attributes9748845
Ref: library/logging id29748997
Ref: 2e8c9748997
Ref: library/logging logrecord-attributes9748997
Ref: 2e589748997
Node: LoggerAdapter Objects9757858
Ref: library/logging logger-adapter9758006
Ref: 2e8d9758006
Ref: library/logging loggeradapter-objects9758006
Ref: 2e8e9758006
Ref: library/logging logging LoggerAdapter9758287
Ref: 133e9758287
Ref: library/logging logging LoggerAdapter process9758841
Ref: 2e909758841
Ref: library/logging logging LoggerAdapter manager9759296
Ref: 2e919759296
Ref: library/logging logging LoggerAdapter _log9759391
Ref: 2e929759391
Node: Thread Safety9760603
Ref: library/logging thread-safety9760753
Ref: 2e939760753
Node: Module-Level Functions9761412
Ref: library/logging module-level-functions9761564
Ref: 2e949761564
Ref: library/logging logging getLogger9761722
Ref: 96a9761722
Ref: library/logging logging getLoggerClass9762453
Ref: 2e959762453
Ref: library/logging logging getLogRecordFactory9762925
Ref: 2e8a9762925
Ref: library/logging logging debug9763388
Ref: 2e5a9763388
Ref: library/logging logging info9764280
Ref: 2e839764280
Ref: library/logging logging warning9764489
Ref: 2ff9764489
Ref: library/logging logging error9764912
Ref: 2e979764912
Ref: library/logging logging critical9765123
Ref: 2e989765123
Ref: library/logging logging exception9765340
Ref: 14e39765340
Ref: library/logging logging log9765672
Ref: 2e999765672
Ref: library/logging logging disable9765878
Ref: 2e9a9765878
Ref: library/logging logging addLevelName9767094
Ref: 2e9b9767094
Ref: library/logging logging getLevelNamesMapping9767752
Ref: 65c9767752
Ref: library/logging logging getLevelName9768081
Ref: 2e9d9768081
Ref: library/logging logging getHandlerByName9769721
Ref: 19089769721
Ref: library/logging logging getHandlerNames9769906
Ref: 180d9769906
Ref: library/logging logging makeLogRecord9770036
Ref: 2e879770036
Ref: library/logging logging basicConfig9770390
Ref: a0b9770390
Ref: library/logging logging shutdown9775800
Ref: 2e9e9775800
Ref: library/logging logging setLoggerClass9776242
Ref: 2e969776242
Ref: library/logging logging setLogRecordFactory9776858
Ref: 2e8b9776858
Ref: Module-Level Functions-Footnote-19778195
Node: Module-Level Attributes9778260
Ref: library/logging module-level-attributes9778435
Ref: 2e9f9778435
Ref: library/logging logging lastResort9778504
Ref: 123f9778504
Ref: library/logging logging raiseExceptions9779111
Ref: 123e9779111
Node: Integration with the warnings module9779500
Ref: library/logging integration-with-the-warnings-module9779644
Ref: 2ea09779644
Ref: library/logging logging captureWarnings9779861
Ref: 2ea19779861
Ref: Integration with the warnings module-Footnote-19781243
Ref: Integration with the warnings module-Footnote-29781285
Node: logging config — Logging configuration9781338
Ref: library/logging config doc9781542
Ref: 2ea29781542
Ref: library/logging config logging-config-logging-configuration9781542
Ref: 2ea39781542
Ref: library/logging config module-logging config9781542
Ref: 889781542
Ref: library/logging config translation-repo9781542
Ref: 2ea49781542
Ref: logging config — Logging configuration-Footnote-19782193
Node: Configuration functions9782267
Ref: library/logging config configuration-functions9782399
Ref: 2ea59782399
Ref: library/logging config logging-config-api9782399
Ref: 133a9782399
Ref: library/logging config logging config dictConfig9782831
Ref: 11f49782831
Ref: library/logging config logging config fileConfig9784929
Ref: b6c9784929
Ref: library/logging config logging config listen9787647
Ref: f9e9787647
Ref: library/logging config logging-eval-security9789301
Ref: 2eaa9789301
Ref: library/logging config logging config stopListening9790952
Ref: 2ea99790952
Node: Security considerations9791191
Ref: library/logging config security-considerations9791363
Ref: 2eab9791363
Node: Configuration dictionary schema9792081
Ref: library/logging config configuration-dictionary-schema9792255
Ref: 2ead9792255
Ref: library/logging config logging-config-dictschema9792255
Ref: 2ea69792255
Node: Dictionary Schema Details9793272
Ref: library/logging config dictionary-schema-details9793399
Ref: 2eaf9793399
Ref: library/logging config logging-config-dictschema-formatters9794206
Ref: 2eb09794206
Node: Incremental Configuration9799072
Ref: library/logging config incremental-configuration9799226
Ref: 2eb29799226
Ref: library/logging config logging-config-dict-incremental9799226
Ref: 2eb19799226
Node: Object connections9800671
Ref: library/logging config logging-config-dict-connections9800820
Ref: 2eae9800820
Ref: library/logging config object-connections9800820
Ref: 2eb39800820
Node: User-defined objects9803215
Ref: library/logging config logging-config-dict-userdef9803366
Ref: 2eac9803366
Ref: library/logging config user-defined-objects9803366
Ref: 2eb49803366
Node: Handler configuration order9807954
Ref: library/logging config handler-config-dict-order9808113
Ref: 2eb59808113
Ref: library/logging config handler-configuration-order9808113
Ref: 2eb69808113
Node: Access to external objects9809426
Ref: library/logging config access-to-external-objects9809591
Ref: 2eb79809591
Ref: library/logging config logging-config-dict-externalobj9809591
Ref: 2eb89809591
Node: Access to internal objects9810890
Ref: library/logging config access-to-internal-objects9811066
Ref: 2eb99811066
Ref: library/logging config logging-config-dict-internalobj9811066
Ref: 2eba9811066
Node: Import resolution and custom importers9814504
Ref: library/logging config import-resolution-and-custom-importers9814696
Ref: 2ebc9814696
Ref: library/logging config logging-import-resolution9814696
Ref: 2ebd9814696
Node: Configuring QueueHandler and QueueListener9815676
Ref: library/logging config configure-queue9815833
Ref: 16e39815833
Ref: library/logging config configuring-queuehandler-and-queuelistener9815833
Ref: 2ebe9815833
Node: Configuration file format9819040
Ref: library/logging config configuration-file-format9819182
Ref: 2ec39819182
Ref: library/logging config logging-config-fileformat9819182
Ref: 2ea79819182
Node: logging handlers — Logging handlers9826512
Ref: library/logging handlers doc9826740
Ref: 2ec49826740
Ref: library/logging handlers logging-handlers-logging-handlers9826740
Ref: 2ec59826740
Ref: library/logging handlers module-logging handlers9826740
Ref: 899826740
Ref: library/logging handlers translation-repo9826740
Ref: 2ec69826740
Ref: logging handlers — Logging handlers-Footnote-19827809
Node: StreamHandler9827886
Ref: library/logging handlers stream-handler9827993
Ref: 2ec79827993
Ref: library/logging handlers streamhandler9827993
Ref: 2ec89827993
Ref: library/logging handlers logging StreamHandler9828307
Ref: 123d9828307
Ref: library/logging handlers logging StreamHandler emit9828538
Ref: 2ec99828538
Ref: library/logging handlers logging StreamHandler flush9828888
Ref: 2ecb9828888
Ref: library/logging handlers logging StreamHandler setStream9829168
Ref: b6b9829168
Ref: library/logging handlers logging StreamHandler terminator9829584
Ref: 2eca9829584
Node: FileHandler9830000
Ref: library/logging handlers file-handler9830127
Ref: 2ecc9830127
Ref: library/logging handlers filehandler9830127
Ref: 2ecd9830127
Ref: library/logging handlers logging FileHandler9830362
Ref: 19f99830362
Ref: library/logging handlers logging FileHandler close9831172
Ref: 2ecf9831172
Ref: library/logging handlers logging FileHandler emit9831227
Ref: 2ece9831227
Ref: FileHandler-Footnote-19831515
Node: NullHandler9831580
Ref: library/logging handlers null-handler9831712
Ref: 2ed09831712
Ref: library/logging handlers nullhandler9831712
Ref: 2ed19831712
Ref: library/logging handlers logging NullHandler9831973
Ref: 12cb9831973
Ref: library/logging handlers logging NullHandler emit9832066
Ref: 2ed29832066
Ref: library/logging handlers logging NullHandler handle9832135
Ref: 2ed39832135
Ref: library/logging handlers logging NullHandler createLock9832206
Ref: 2ed49832206
Node: WatchedFileHandler9832489
Ref: library/logging handlers watched-file-handler9832629
Ref: 2ed69832629
Ref: library/logging handlers watchedfilehandler9832629
Ref: 2ed79832629
Ref: library/logging handlers logging handlers WatchedFileHandler9833639
Ref: 2ed89833639
Ref: library/logging handlers logging handlers WatchedFileHandler reopenIfNeeded9834465
Ref: cdc9834465
Ref: library/logging handlers logging handlers WatchedFileHandler emit9834758
Ref: 2ed99834758
Node: BaseRotatingHandler9834926
Ref: library/logging handlers base-rotating-handler9835074
Ref: 2eda9835074
Ref: library/logging handlers baserotatinghandler9835074
Ref: 2edb9835074
Ref: library/logging handlers logging handlers BaseRotatingHandler9835456
Ref: 2edc9835456
Ref: library/logging handlers logging handlers BaseRotatingHandler namer9835645
Ref: 2edd9835645
Ref: library/logging handlers logging handlers BaseRotatingHandler rotator9837370
Ref: 2ee09837370
Ref: library/logging handlers logging handlers BaseRotatingHandler rotation_filename9837639
Ref: 2ede9837639
Ref: library/logging handlers logging handlers BaseRotatingHandler rotate9838210
Ref: 2ee19838210
Node: RotatingFileHandler9839522
Ref: library/logging handlers rotating-file-handler9839676
Ref: 2ee39839676
Ref: library/logging handlers rotatingfilehandler9839676
Ref: 2ee49839676
Ref: library/logging handlers logging handlers RotatingFileHandler9839863
Ref: 16e09839863
Ref: library/logging handlers logging handlers RotatingFileHandler doRollover9841828
Ref: 2ee69841828
Ref: library/logging handlers logging handlers RotatingFileHandler emit9841908
Ref: 2ee59841908
Ref: library/logging handlers logging handlers RotatingFileHandler shouldRollover9842040
Ref: 2ee79842040
Node: TimedRotatingFileHandler9842188
Ref: library/logging handlers timed-rotating-file-handler9842336
Ref: 2ee89842336
Ref: library/logging handlers timedrotatingfilehandler9842336
Ref: 2ee99842336
Ref: library/logging handlers logging handlers TimedRotatingFileHandler9842564
Ref: f9a9842564
Ref: library/logging handlers logging handlers TimedRotatingFileHandler doRollover9847708
Ref: 2eeb9847708
Ref: library/logging handlers logging handlers TimedRotatingFileHandler emit9847788
Ref: 2eea9847788
Ref: library/logging handlers logging handlers TimedRotatingFileHandler getFilesToDelete9847915
Ref: 2edf9847915
Ref: library/logging handlers logging handlers TimedRotatingFileHandler shouldRollover9848142
Ref: 2eec9848142
Node: SocketHandler9848306
Ref: library/logging handlers socket-handler9848450
Ref: 2eed9848450
Ref: library/logging handlers sockethandler9848450
Ref: 2eee9848450
Ref: library/logging handlers logging handlers SocketHandler9848658
Ref: f9b9848658
Ref: library/logging handlers logging handlers SocketHandler close9849059
Ref: 2eef9849059
Ref: library/logging handlers logging handlers SocketHandler emit9849116
Ref: 2ef09849116
Ref: library/logging handlers logging handlers SocketHandler handleError9849552
Ref: 2ef19849552
Ref: library/logging handlers logging handlers SocketHandler makeSocket9849782
Ref: 2ef29849782
Ref: library/logging handlers logging handlers SocketHandler makePickle9850026
Ref: 2ef39850026
Ref: library/logging handlers logging handlers SocketHandler send9850836
Ref: 2ef49850836
Ref: library/logging handlers logging handlers SocketHandler createSocket9851157
Ref: 6609851157
Node: DatagramHandler9852357
Ref: library/logging handlers datagram-handler9852490
Ref: 2ef59852490
Ref: library/logging handlers datagramhandler9852490
Ref: 2ef69852490
Ref: library/logging handlers logging handlers DatagramHandler9852721
Ref: f9c9852721
Ref: library/logging handlers logging handlers DatagramHandler emit9853629
Ref: 2ef79853629
Ref: library/logging handlers logging handlers DatagramHandler makeSocket9853984
Ref: 2ef89853984
Ref: library/logging handlers logging handlers DatagramHandler send9854171
Ref: 2ef99854171
Node: SysLogHandler9854386
Ref: library/logging handlers syslog-handler9854523
Ref: 2efa9854523
Ref: library/logging handlers sysloghandler9854523
Ref: 2efb9854523
Ref: library/logging handlers logging handlers SysLogHandler9854724
Ref: 65f9854724
Ref: library/logging handlers logging handlers SysLogHandler close9856669
Ref: 2efc9856669
Ref: library/logging handlers logging handlers SysLogHandler createSocket9856745
Ref: 65e9856745
Ref: library/logging handlers logging handlers SysLogHandler emit9857200
Ref: 2efd9857200
Ref: library/logging handlers logging handlers SysLogHandler encodePriority9859082
Ref: 2efe9859082
Ref: library/logging handlers logging handlers SysLogHandler mapPriority9863090
Ref: 2eff9863090
Ref: SysLogHandler-Footnote-19863580
Ref: SysLogHandler-Footnote-29863635
Ref: SysLogHandler-Footnote-39863700
Ref: SysLogHandler-Footnote-49863759
Node: NTEventLogHandler9863824
Ref: library/logging handlers nt-eventlog-handler9863957
Ref: 2f009863957
Ref: library/logging handlers nteventloghandler9863957
Ref: 2f019863957
Ref: library/logging handlers logging handlers NTEventLogHandler9864287
Ref: 2f029864287
Ref: library/logging handlers logging handlers NTEventLogHandler close9865342
Ref: 2f039865342
Ref: library/logging handlers logging handlers NTEventLogHandler emit9865744
Ref: 2f049865744
Ref: library/logging handlers logging handlers NTEventLogHandler getEventCategory9865902
Ref: 2f059865902
Ref: library/logging handlers logging handlers NTEventLogHandler getEventType9866104
Ref: 2f069866104
Ref: library/logging handlers logging handlers NTEventLogHandler getMessageID9866691
Ref: 2f079866691
Node: SMTPHandler9867121
Ref: library/logging handlers smtp-handler9867254
Ref: 2f089867254
Ref: library/logging handlers smtphandler9867254
Ref: 2f099867254
Ref: library/logging handlers logging handlers SMTPHandler9867446
Ref: 166d9867446
Ref: library/logging handlers logging handlers SMTPHandler emit9868694
Ref: 2f0a9868694
Ref: library/logging handlers logging handlers SMTPHandler getSubject9868798
Ref: 2f0b9868798
Node: MemoryHandler9868944
Ref: library/logging handlers memory-handler9869071
Ref: 2f0c9869071
Ref: library/logging handlers memoryhandler9869071
Ref: 2f0d9869071
Ref: library/logging handlers logging handlers BufferingHandler9869769
Ref: 2f0e9869769
Ref: library/logging handlers logging handlers BufferingHandler emit9869965
Ref: 2f0f9869965
Ref: library/logging handlers logging handlers BufferingHandler flush9870155
Ref: 2f119870155
Ref: library/logging handlers logging handlers BufferingHandler shouldFlush9870385
Ref: 2f109870385
Ref: library/logging handlers logging handlers MemoryHandler9870568
Ref: 2ebb9870568
Ref: library/logging handlers logging handlers MemoryHandler close9871376
Ref: 2f139871376
Ref: library/logging handlers logging handlers MemoryHandler flush9871504
Ref: 2f149871504
Ref: library/logging handlers logging handlers MemoryHandler setTarget9871805
Ref: 2f129871805
Ref: library/logging handlers logging handlers MemoryHandler shouldFlush9871895
Ref: 2f159871895
Node: HTTPHandler9872021
Ref: library/logging handlers http-handler9872149
Ref: 2f169872149
Ref: library/logging handlers httphandler9872149
Ref: 2f179872149
Ref: library/logging handlers logging handlers HTTPHandler9872375
Ref: e5e9872375
Ref: library/logging handlers logging handlers HTTPHandler mapLogRecord9873330
Ref: 2f189873330
Ref: library/logging handlers logging handlers HTTPHandler emit9873787
Ref: 2f199873787
Node: QueueHandler9874515
Ref: library/logging handlers queue-handler9874643
Ref: 2f1a9874643
Ref: library/logging handlers queuehandler9874643
Ref: 2f1b9874643
Ref: library/logging handlers logging handlers QueueHandler9875379
Ref: 19079875379
Ref: library/logging handlers logging handlers QueueHandler emit9876495
Ref: 2f1e9876495
Ref: library/logging handlers logging handlers QueueHandler prepare9876991
Ref: 2f1f9876991
Ref: library/logging handlers logging handlers QueueHandler enqueue9878930
Ref: 2f1c9878930
Ref: library/logging handlers logging handlers QueueHandler listener9879176
Ref: 2ebf9879176
Node: QueueListener9879471
Ref: library/logging handlers queue-listener9879579
Ref: 2f209879579
Ref: library/logging handlers queuelistener9879579
Ref: 2f219879579
Ref: library/logging handlers logging handlers QueueListener9880589
Ref: e5f9880589
Ref: library/logging handlers logging handlers QueueListener dequeue9881815
Ref: 2f229881815
Ref: library/logging handlers logging handlers QueueListener prepare9882096
Ref: 2f239882096
Ref: library/logging handlers logging handlers QueueListener handle9882413
Ref: 2f249882413
Ref: library/logging handlers logging handlers QueueListener start9882675
Ref: 164b9882675
Ref: library/logging handlers logging handlers QueueListener stop9882965
Ref: 2f259882965
Ref: library/logging handlers logging handlers QueueListener enqueue_sentinel9883276
Ref: 2f269883276
Node: platform — Access to underlying platform’s identifying data9883775
Ref: library/platform doc9884002
Ref: 2f279884002
Ref: library/platform module-platform9884002
Ref: aa9884002
Ref: library/platform platform-access-to-underlying-platform-s-identifying-data9884002
Ref: 2f289884002
Ref: library/platform translation-repo9884002
Ref: 2f299884002
Ref: platform — Access to underlying platform’s identifying data-Footnote-19884597
Node: Cross platform9884665
Ref: library/platform cross-platform9884801
Ref: 2f2a9884801
Ref: library/platform platform architecture9884850
Ref: 179e9884850
Ref: library/platform platform machine9886179
Ref: 2f2b9886179
Ref: library/platform platform node9886429
Ref: 2f2c9886429
Ref: library/platform platform platform9886604
Ref: 18699886604
Ref: library/platform platform processor9887547
Ref: 2f2e9887547
Ref: library/platform platform python_build9887868
Ref: 2f2f9887868
Ref: library/platform platform python_compiler9888015
Ref: 2f309888015
Ref: library/platform platform python_branch9888138
Ref: 2f319888138
Ref: library/platform platform python_implementation9888252
Ref: 2f329888252
Ref: library/platform platform python_revision9888456
Ref: 2f339888456
Ref: library/platform platform python_version9888579
Ref: 2f349888579
Ref: library/platform platform python_version_tuple9888828
Ref: 2f359888828
Ref: library/platform platform release9889108
Ref: 2f369889108
Ref: library/platform platform system9889285
Ref: 20089889285
Ref: library/platform platform system_alias9889714
Ref: 2f2d9889714
Ref: library/platform platform version9889997
Ref: 2f379889997
Ref: library/platform platform uname9890316
Ref: 1bc29890316
Node: Java platform9891072
Ref: library/platform java-platform9891233
Ref: 2f389891233
Ref: library/platform platform java_ver9891280
Ref: 2a79891280
Node: Windows platform9891917
Ref: library/platform windows-platform9892078
Ref: 2f399892078
Ref: library/platform platform win32_ver9892131
Ref: 1af19892131
Ref: library/platform platform win32_edition9892959
Ref: 2f3a9892959
Ref: library/platform platform win32_is_iot9893289
Ref: 2f3b9893289
Node: macOS platform9893483
Ref: library/platform macos-platform9893643
Ref: 2f3c9893643
Ref: library/platform platform mac_ver9893692
Ref: 1bc49893692
Node: iOS platform9894073
Ref: library/platform ios-platform9894231
Ref: 2f3d9894231
Ref: library/platform platform ios_ver9894276
Ref: 20079894276
Node: Unix platforms9895051
Ref: library/platform unix-platforms9895210
Ref: 2f3e9895210
Ref: library/platform platform libc_ver9895259
Ref: 1bc19895259
Node: Linux platforms9895876
Ref: library/platform linux-platforms9896039
Ref: 2f3f9896039
Ref: library/platform platform freedesktop_os_release9896090
Ref: 82c9896090
Ref: Linux platforms-Footnote-19897556
Node: Android platform9897629
Ref: library/platform android-platform9897799
Ref: 2f409897799
Ref: library/platform platform android_ver9897852
Ref: 175a9897852
Ref: Android platform-Footnote-19898990
Ref: Android platform-Footnote-29899069
Ref: Android platform-Footnote-39899140
Ref: Android platform-Footnote-49899212
Node: Command-line usage<2>9899286
Ref: library/platform command-line-usage9899432
Ref: 2f419899432
Ref: library/platform platform-cli9899432
Ref: 2f429899432
Ref: library/platform cmdoption-platform-terse9899698
Ref: 2f439899698
Ref: library/platform cmdoption-platform-nonaliased9899888
Ref: 2f449899888
Node: errno — Standard errno system symbols9900282
Ref: library/errno doc9900520
Ref: 2f459900520
Ref: library/errno errno-standard-errno-system-symbols9900520
Ref: 2f469900520
Ref: library/errno module-errno9900520
Ref: 579900520
Ref: library/errno translation-repo9900520
Ref: 2f479900520
Ref: library/errno errno errorcode9900923
Ref: 2f489900923
Ref: library/errno errno EPERM9901444
Ref: 18fc9901444
Ref: library/errno errno ENOENT9901570
Ref: 24639901570
Ref: library/errno errno ESRCH9901701
Ref: 24679901701
Ref: library/errno errno EINTR9901823
Ref: db59901823
Ref: library/errno errno EIO9901950
Ref: 2f499901950
Ref: library/errno errno ENXIO9901987
Ref: 2f4a9901987
Ref: library/errno errno E2BIG9902042
Ref: 2f4b9902042
Ref: library/errno errno ENOEXEC9902089
Ref: 2f4c9902089
Ref: library/errno errno EBADF9902138
Ref: 9659902138
Ref: library/errno errno ECHILD9902183
Ref: 245c9902183
Ref: library/errno errno EAGAIN9902308
Ref: 24579902308
Ref: library/errno errno ENOMEM9902422
Ref: 2f4d9902422
Ref: library/errno errno EACCES9902466
Ref: 24669902466
Ref: library/errno errno EFAULT9902587
Ref: 2f4e9902587
Ref: library/errno errno ENOTBLK9902629
Ref: 2f4f9902629
Ref: library/errno errno EBUSY9902682
Ref: 2f509902682
Ref: library/errno errno EEXIST9902735
Ref: 24629902735
Ref: library/errno errno EXDEV9902851
Ref: 2d389902851
Ref: library/errno errno ENODEV9902898
Ref: 2f519902898
Ref: library/errno errno ENOTDIR9902943
Ref: 24659902943
Ref: library/errno errno EISDIR9903067
Ref: 24649903067
Ref: library/errno errno EINVAL9903188
Ref: 1b7f9903188
Ref: library/errno errno ENFILE9903235
Ref: 2f529903235
Ref: library/errno errno EMFILE9903285
Ref: 2f539903285
Ref: library/errno errno ENOTTY9903335
Ref: 2f549903335
Ref: library/errno errno ETXTBSY9903382
Ref: 2f559903382
Ref: library/errno errno EFBIG9903428
Ref: 2f569903428
Ref: library/errno errno ENOSPC9903472
Ref: 2f579903472
Ref: library/errno errno ESPIPE9903526
Ref: 2f589903526
Ref: library/errno errno EROFS9903569
Ref: 2f599903569
Ref: library/errno errno EMLINK9903620
Ref: 2f5a9903620
Ref: library/errno errno EPIPE9903665
Ref: 245d9903665
Ref: library/errno errno EDOM9903780
Ref: 2f5b9903780
Ref: library/errno errno ERANGE9903844
Ref: 2f5c9903844
Ref: library/errno errno EDEADLK9903904
Ref: 2f5d9903904
Ref: library/errno errno ENAMETOOLONG9903965
Ref: 2f5e9903965
Ref: library/errno errno ENOLCK9904020
Ref: 2f5f9904020
Ref: library/errno errno ENOSYS9904076
Ref: 18fd9904076
Ref: library/errno errno ENOTEMPTY9904131
Ref: 2f609904131
Ref: library/errno errno ELOOP9904184
Ref: 2f619904184
Ref: library/errno errno EWOULDBLOCK9904249
Ref: 24599904249
Ref: library/errno errno ENOMSG9904380
Ref: 2f629904380
Ref: library/errno errno EIDRM9904437
Ref: 2f639904437
Ref: library/errno errno ECHRNG9904485
Ref: 2f649904485
Ref: library/errno errno EL2NSYNC9904543
Ref: 2f659904543
Ref: library/errno errno EL3HLT9904600
Ref: 2f669904600
Ref: library/errno errno EL3RST9904645
Ref: 2f679904645
Ref: library/errno errno ELNRNG9904689
Ref: 2f689904689
Ref: library/errno errno EUNATCH9904744
Ref: 2f699904744
Ref: library/errno errno ENOCSI9904804
Ref: 2f6a9904804
Ref: library/errno errno EL2HLT9904861
Ref: 2f6b9904861
Ref: library/errno errno EBADE9904906
Ref: 2f6c9904906
Ref: library/errno errno EBADR9904952
Ref: 2f6d9904952
Ref: library/errno errno EXFULL9905008
Ref: 2f6e9905008
Ref: library/errno errno ENOANO9905052
Ref: 2f6f9905052
Ref: library/errno errno EBADRQC9905091
Ref: 2f709905091
Ref: library/errno errno EBADSLT9905143
Ref: 2f719905143
Ref: library/errno errno EDEADLOCK9905187
Ref: 2f729905187
Ref: library/errno errno EBFONT9905248
Ref: 2f739905248
Ref: library/errno errno ENOSTR9905299
Ref: 2f749905299
Ref: library/errno errno ENODATA9905349
Ref: 2f759905349
Ref: library/errno errno ETIME9905398
Ref: 2f769905398
Ref: library/errno errno ENOSR9905441
Ref: 2f779905441
Ref: library/errno errno ENONET9905495
Ref: 2f789905495
Ref: library/errno errno ENOPKG9905555
Ref: 2f799905555
Ref: library/errno errno EREMOTE9905607
Ref: 2f7a9905607
Ref: library/errno errno ENOLINK9905655
Ref: 2f7b9905655
Ref: library/errno errno EADV9905708
Ref: 2f7c9905708
Ref: library/errno errno ESRMNT9905752
Ref: 2f7d9905752
Ref: library/errno errno ECOMM9905796
Ref: 2f7e9905796
Ref: library/errno errno EPROTO9905853
Ref: 2f7f9905853
Ref: library/errno errno EMULTIHOP9905898
Ref: 2f809905898
Ref: library/errno errno EDOTDOT9905950
Ref: 2f819905950
Ref: library/errno errno EBADMSG9906000
Ref: 2f829906000
Ref: library/errno errno EOVERFLOW9906050
Ref: 2f839906050
Ref: library/errno errno ENOTUNIQ9906121
Ref: 2f849906121
Ref: library/errno errno EBADFD9906180
Ref: 2f859906180
Ref: library/errno errno EREMCHG9906239
Ref: 2f869906239
Ref: library/errno errno ELIBACC9906293
Ref: 2f879906293
Ref: library/errno errno ELIBBAD9906363
Ref: 2f889906363
Ref: library/errno errno ELIBSCN9906431
Ref: 2f899906431
Ref: library/errno errno ELIBMAX9906494
Ref: 2f8a9906494
Ref: library/errno errno ELIBEXEC9906573
Ref: 2f8b9906573
Ref: library/errno errno EILSEQ9906643
Ref: 2f8c9906643
Ref: library/errno errno ERESTART9906695
Ref: 2f8d9906695
Ref: library/errno errno ESTRPIPE9906771
Ref: 2f8e9906771
Ref: library/errno errno EUSERS9906822
Ref: 2f8f9906822
Ref: library/errno errno ENOTSOCK9906867
Ref: 2f909906867
Ref: library/errno errno EDESTADDRREQ9906930
Ref: 2f919906930
Ref: library/errno errno EMSGSIZE9906995
Ref: 2f929906995
Ref: library/errno errno EPROTOTYPE9907044
Ref: 2f939907044
Ref: library/errno errno ENOPROTOOPT9907109
Ref: 2f949907109
Ref: library/errno errno EPROTONOSUPPORT9907167
Ref: 2f959907167
Ref: library/errno errno ESOCKTNOSUPPORT9907229
Ref: 2f969907229
Ref: library/errno errno EOPNOTSUPP9907294
Ref: 2f979907294
Ref: library/errno errno ENOTSUP9907374
Ref: 2f989907374
Ref: library/errno errno EPFNOSUPPORT9907457
Ref: 2f999907457
Ref: library/errno errno EAFNOSUPPORT9907523
Ref: 2f9a9907523
Ref: library/errno errno EADDRINUSE9907600
Ref: 2f9b9907600
Ref: library/errno errno EADDRNOTAVAIL9907657
Ref: 2f9c9907657
Ref: library/errno errno ENETDOWN9907726
Ref: 2f9d9907726
Ref: library/errno errno ENETUNREACH9907774
Ref: 1b979907774
Ref: library/errno errno ENETRESET9907832
Ref: 2f9e9907832
Ref: library/errno errno ECONNABORTED9907909
Ref: 245f9907909
Ref: library/errno errno ECONNRESET9908059
Ref: 24619908059
Ref: library/errno errno ENOBUFS9908197
Ref: 19179908197
Ref: library/errno errno EISCONN9908254
Ref: 2f9f9908254
Ref: library/errno errno ENOTCONN9908325
Ref: 2fa09908325
Ref: library/errno errno ESHUTDOWN9908393
Ref: 245e9908393
Ref: library/errno errno ETOOMANYREFS9908546
Ref: 2fa19908546
Ref: library/errno errno ETIMEDOUT9908617
Ref: 24689908617
Ref: library/errno errno ECONNREFUSED9908741
Ref: 24609908741
Ref: library/errno errno EHOSTDOWN9908877
Ref: 2fa29908877
Ref: library/errno errno EHOSTUNREACH9908923
Ref: 2fa39908923
Ref: library/errno errno EALREADY9908976
Ref: 24589908976
Ref: library/errno errno EINPROGRESS9909112
Ref: 245a9909112
Ref: library/errno errno ESTALE9909247
Ref: 2fa49909247
Ref: library/errno errno EUCLEAN9909299
Ref: 2fa59909299
Ref: library/errno errno ENOTNAM9909355
Ref: 2fa69909355
Ref: library/errno errno ENAVAIL9909414
Ref: 2fa79909414
Ref: library/errno errno EISNAM9909475
Ref: 2fa89909475
Ref: library/errno errno EREMOTEIO9909526
Ref: 2fa99909526
Ref: library/errno errno EDQUOT9909576
Ref: 2faa9909576
Ref: library/errno errno EQFULL9909621
Ref: 2fab9909621
Ref: library/errno errno ENOMEDIUM9909711
Ref: 2fac9909711
Ref: library/errno errno EMEDIUMTYPE9909760
Ref: 2fad9909760
Ref: library/errno errno ENOKEY9909813
Ref: 2fae9909813
Ref: library/errno errno EKEYEXPIRED9909870
Ref: 2faf9909870
Ref: library/errno errno EKEYREVOKED9909921
Ref: 2fb09909921
Ref: library/errno errno EKEYREJECTED9909977
Ref: 2fb19909977
Ref: library/errno errno ERFKILL9910041
Ref: 2fb29910041
Ref: library/errno errno ELOCKUNMAPPED9910110
Ref: 2fb39910110
Ref: library/errno errno ENOTACTIVE9910172
Ref: 2fb49910172
Ref: library/errno errno EAUTH9910229
Ref: 2fb59910229
Ref: library/errno errno EBADARCH9910307
Ref: 2fb69910307
Ref: library/errno errno EBADEXEC9910394
Ref: 2fb79910394
Ref: library/errno errno EBADMACHO9910489
Ref: 2fb89910489
Ref: library/errno errno EDEVERR9910572
Ref: 2fb99910572
Ref: library/errno errno EFTYPE9910644
Ref: 2fba9910644
Ref: library/errno errno ENEEDAUTH9910736
Ref: 2fbb9910736
Ref: library/errno errno ENOATTR9910816
Ref: 2fbc9910816
Ref: library/errno errno ENOPOLICY9910895
Ref: 2fbd9910895
Ref: library/errno errno EPROCLIM9910973
Ref: 2fbe9910973
Ref: library/errno errno EPROCUNAVAIL9911052
Ref: 2fbf9911052
Ref: library/errno errno EPROGMISMATCH9911142
Ref: 2fc09911142
Ref: library/errno errno EPROGUNAVAIL9911229
Ref: 2fc19911229
Ref: library/errno errno EPWROFF9911314
Ref: 2fc29911314
Ref: library/errno errno EBADRPC9911393
Ref: 2fc39911393
Ref: library/errno errno ERPCMISMATCH9911470
Ref: 2fc49911470
Ref: library/errno errno ESHLIBVERS9911552
Ref: 2fc59911552
Ref: library/errno errno ENOTCAPABLE9911646
Ref: 18e39911646
Ref: library/errno errno ECANCELED9911858
Ref: 16189911858
Ref: library/errno errno EOWNERDEAD9911938
Ref: 2fc69911938
Ref: library/errno errno ENOTRECOVERABLE9912011
Ref: 2fc79912011
Node: ctypes — A foreign function library for Python9912100
Ref: library/ctypes doc9912266
Ref: 2fc89912266
Ref: library/ctypes ctypes-a-foreign-function-library-for-python9912266
Ref: 2fc99912266
Ref: library/ctypes module-ctypes9912266
Ref: 2a9912266
Ref: library/ctypes translation-repo9912266
Ref: 2fca9912266
Ref: ctypes — A foreign function library for Python-Footnote-19912778
Node: ctypes tutorial9912841
Ref: library/ctypes ctypes-ctypes-tutorial9912966
Ref: 2fcb9912966
Ref: library/ctypes ctypes-tutorial9912966
Ref: 2fcc9912966
Node: Loading dynamic link libraries9914347
Ref: library/ctypes ctypes-loading-dynamic-link-libraries9914474
Ref: 2fcf9914474
Ref: library/ctypes loading-dynamic-link-libraries9914474
Ref: 2fd09914474
Node: Accessing functions from loaded dlls9916527
Ref: library/ctypes accessing-functions-from-loaded-dlls9916680
Ref: 2fd29916680
Ref: library/ctypes ctypes-accessing-functions-from-loaded-dlls9916680
Ref: 2fd39916680
Node: Calling functions9918902
Ref: library/ctypes calling-functions9919047
Ref: 2fd49919047
Ref: library/ctypes ctypes-calling-functions9919047
Ref: 2fd59919047
Node: Fundamental data types9921469
Ref: library/ctypes ctypes-fundamental-data-types9921605
Ref: 2fd69921605
Ref: library/ctypes fundamental-data-types9921605
Ref: 2fd79921605
Node: Calling functions continued9931583
Ref: library/ctypes calling-functions-continued9931728
Ref: 2fec9931728
Ref: library/ctypes ctypes-calling-functions-continued9931728
Ref: 2fed9931728
Node: Calling variadic functions9932801
Ref: library/ctypes calling-variadic-functions9932973
Ref: 2fee9932973
Ref: library/ctypes ctypes-calling-variadic-functions9932973
Ref: 2fef9932973
Node: Calling functions with your own custom data types9933668
Ref: library/ctypes calling-functions-with-your-own-custom-data-types9933871
Ref: 2ff09933871
Ref: library/ctypes ctypes-calling-functions-with-own-custom-data-types9933871
Ref: 2ff19933871
Node: Specifying the required argument types function prototypes9934772
Ref: library/ctypes ctypes-specifying-required-argument-types9934961
Ref: 2ff29934961
Ref: library/ctypes specifying-the-required-argument-types-function-prototypes9934961
Ref: 2ff39934961
Node: Return types9936850
Ref: library/ctypes ctypes-return-types9937041
Ref: 2ff59937041
Ref: library/ctypes return-types9937041
Ref: 2ff69937041
Node: Passing pointers or passing parameters by reference9940164
Ref: library/ctypes ctypes-passing-pointers9940318
Ref: 2ffa9940318
Ref: library/ctypes passing-pointers-or-passing-parameters-by-reference9940318
Ref: 2ffb9940318
Node: Structures and unions9941391
Ref: library/ctypes ctypes-structures-unions9941573
Ref: 2ffd9941573
Ref: library/ctypes structures-and-unions9941573
Ref: 2ffe9941573
Ref: library/ctypes ctypes-structureunion-alignment-byte-order9943648
Ref: 30009943648
Node: Structure/union alignment and byte order9943971
Ref: library/ctypes structure-union-alignment-and-byte-order9944137
Ref: 30019944137
Node: Bit fields in structures and unions9945170
Ref: library/ctypes bit-fields-in-structures-and-unions9945321
Ref: 30059945321
Ref: library/ctypes ctypes-bit-fields-in-structures-unions9945321
Ref: 30069945321
Node: Arrays9945913
Ref: library/ctypes arrays9946032
Ref: 30079946032
Ref: library/ctypes ctypes-arrays9946032
Ref: 30089946032
Node: Pointers9947319
Ref: library/ctypes ctypes-pointers9947419
Ref: 30099947419
Ref: library/ctypes pointers9947419
Ref: 300a9947419
Node: Type conversions9950060
Ref: library/ctypes ctypes-type-conversions9950170
Ref: 300c9950170
Ref: library/ctypes type-conversions9950170
Ref: 300d9950170
Node: Incomplete Types9952772
Ref: library/ctypes ctypes-incomplete-types9952892
Ref: 300f9952892
Ref: library/ctypes incomplete-types9952892
Ref: 30109952892
Node: Callback functions9954502
Ref: library/ctypes callback-functions9954641
Ref: 30119954641
Ref: library/ctypes ctypes-callback-functions9954641
Ref: 30129954641
Node: Accessing values exported from dlls9958503
Ref: library/ctypes accessing-values-exported-from-dlls9958635
Ref: 30159958635
Ref: library/ctypes ctypes-accessing-values-exported-from-dlls9958635
Ref: 30169958635
Node: Surprises9961284
Ref: library/ctypes ctypes-surprises9961423
Ref: 30199961423
Ref: library/ctypes surprises9961423
Ref: 301a9961423
Node: Variable-sized data types9963591
Ref: library/ctypes ctypes-variable-sized-data-types9963686
Ref: 301b9963686
Ref: library/ctypes variable-sized-data-types9963686
Ref: 301c9963686
Node: ctypes reference9965077
Ref: library/ctypes ctypes-ctypes-reference9965202
Ref: 301e9965202
Ref: library/ctypes ctypes-reference9965202
Ref: 301f9965202
Node: Finding shared libraries9965525
Ref: library/ctypes ctypes-finding-shared-libraries9965635
Ref: 30209965635
Ref: library/ctypes finding-shared-libraries9965635
Ref: 30219965635
Node: Loading shared libraries9968349
Ref: library/ctypes ctypes-loading-shared-libraries9968485
Ref: 30229968485
Ref: library/ctypes loading-shared-libraries9968485
Ref: 30239968485
Ref: library/ctypes ctypes CDLL9968686
Ref: 9f49968686
Ref: library/ctypes ctypes OleDLL9969808
Ref: 18859969808
Ref: library/ctypes ctypes WinDLL9970666
Ref: 18869970666
Ref: library/ctypes ctypes PyDLL9971266
Ref: 18879971266
Ref: library/ctypes ctypes PyDLL _handle9975088
Ref: 30299975088
Ref: library/ctypes ctypes PyDLL _name9975170
Ref: 302a9975170
Ref: library/ctypes ctypes LibraryLoader9975519
Ref: 302b9975519
Ref: library/ctypes ctypes LibraryLoader LoadLibrary9975977
Ref: 2fd19975977
Ref: Loading shared libraries-Footnote-19977601
Ref: Loading shared libraries-Footnote-29977667
Node: Foreign functions9977713
Ref: library/ctypes ctypes-foreign-functions9977844
Ref: 302c9977844
Ref: library/ctypes foreign-functions9977844
Ref: 302d9977844
Ref: library/ctypes ctypes _CFuncPtr9978540
Ref: 302e9978540
Ref: library/ctypes ctypes _CFuncPtr restype9978842
Ref: 2ff79978842
Ref: library/ctypes ctypes _CFuncPtr argtypes9979519
Ref: 16179979519
Ref: library/ctypes ctypes _CFuncPtr errcheck9980765
Ref: 2ff99980765
Ref: library/ctypes ctypes ArgumentError9981751
Ref: 302f9981751
Node: Function prototypes9982391
Ref: library/ctypes ctypes-function-prototypes9982515
Ref: 30309982515
Ref: library/ctypes function-prototypes9982515
Ref: 30319982515
Ref: library/ctypes ctypes CFUNCTYPE9983096
Ref: 30139983096
Ref: library/ctypes ctypes WINFUNCTYPE9983602
Ref: 30149983602
Ref: library/ctypes ctypes PYFUNCTYPE9983983
Ref: 30329983983
Node: Utility functions9989436
Ref: library/ctypes ctypes-utility-functions9989556
Ref: 30339989556
Ref: library/ctypes utility-functions9989556
Ref: 30349989556
Ref: library/ctypes ctypes addressof9989613
Ref: 30359989613
Ref: library/ctypes ctypes alignment9989857
Ref: 30369989857
Ref: library/ctypes ctypes byref9990017
Ref: 2ffc9990017
Ref: library/ctypes ctypes cast9990531
Ref: 300e9990531
Ref: library/ctypes ctypes create_string_buffer9990825
Ref: 2feb9990825
Ref: library/ctypes ctypes create_unicode_buffer9992322
Ref: 1b5f9992322
Ref: library/ctypes ctypes DllCanUnloadNow9992853
Ref: 30379992853
Ref: library/ctypes ctypes DllGetClassObject9993125
Ref: 30389993125
Ref: library/ctypes ctypes util find_library9993407
Ref: d729993407
Ref: library/ctypes ctypes util find_msvcrt9993880
Ref: 30399993880
Ref: library/ctypes ctypes FormatError9994364
Ref: 303a9994364
Ref: library/ctypes ctypes GetLastError9994630
Ref: 2ff89994630
Ref: library/ctypes ctypes get_errno9994925
Ref: 30259994925
Ref: library/ctypes ctypes get_last_error9995178
Ref: 30279995178
Ref: library/ctypes ctypes memmove9995481
Ref: 303b9995481
Ref: library/ctypes ctypes memset9995725
Ref: 303c9995725
Ref: library/ctypes ctypes POINTER9995978
Ref: 17f59995978
Ref: library/ctypes ctypes pointer9996205
Ref: 17f49996205
Ref: library/ctypes ctypes resize9996514
Ref: 301d9996514
Ref: library/ctypes ctypes set_errno9996852
Ref: 30269996852
Ref: library/ctypes ctypes set_last_error9997160
Ref: 30289997160
Ref: library/ctypes ctypes sizeof9997519
Ref: 303d9997519
Ref: library/ctypes ctypes string_at9997690
Ref: 303e9997690
Ref: library/ctypes ctypes WinError9998002
Ref: 303f9998002
Ref: library/ctypes ctypes wstring_at9998567
Ref: 30409998567
Node: Data types<2>9998925
Ref: library/ctypes ctypes-data-types9999051
Ref: 30419999051
Ref: library/ctypes data-types9999051
Ref: 30429999051
Ref: library/ctypes ctypes _CData9999094
Ref: 30439999094
Ref: library/ctypes ctypes _CData from_buffer9999729
Ref: 30459999729
Ref: library/ctypes ctypes _CData from_buffer_copy10000316
Ref: 304610000316
Ref: library/ctypes ctypes _CData from_address10000861
Ref: 304710000861
Ref: library/ctypes ctypes _CData from_param10001207
Ref: 2ff410001207
Ref: library/ctypes ctypes _CData in_dll10001768
Ref: 301710001768
Ref: library/ctypes ctypes _CData _b_base_10002064
Ref: 304810002064
Ref: library/ctypes ctypes _CData _b_needsfree_10002369
Ref: 304910002369
Ref: library/ctypes ctypes _CData _objects10002543
Ref: 304410002543
Node: Fundamental data types<2>10002855
Ref: library/ctypes ctypes-fundamental-data-types-210002985
Ref: 304a10002985
Ref: library/ctypes id110002985
Ref: 304b10002985
Ref: library/ctypes ctypes _SimpleCData10003052
Ref: 304c10003052
Ref: library/ctypes ctypes _SimpleCData value10003518
Ref: 304d10003518
Ref: library/ctypes ctypes c_byte10004867
Ref: 188310004867
Ref: library/ctypes ctypes c_char10005079
Ref: 2fd910005079
Ref: library/ctypes ctypes c_char_p10005319
Ref: 17f610005319
Ref: library/ctypes ctypes c_double10005613
Ref: 1a5e10005613
Ref: library/ctypes ctypes c_longdouble10005742
Ref: 1a5f10005742
Ref: library/ctypes ctypes c_float10005989
Ref: 2fea10005989
Ref: library/ctypes ctypes c_int10006116
Ref: 2fcd10006116
Ref: library/ctypes ctypes c_int810006380
Ref: 2fdd10006380
Ref: library/ctypes ctypes c_int1610006501
Ref: 2fde10006501
Ref: library/ctypes ctypes c_int3210006627
Ref: 2fdf10006627
Ref: library/ctypes ctypes c_int6410006751
Ref: 2fe010006751
Ref: library/ctypes ctypes c_long10006880
Ref: 2fce10006880
Ref: library/ctypes ctypes c_longlong10007044
Ref: 2fe710007044
Ref: library/ctypes ctypes c_short10007222
Ref: 2fdb10007222
Ref: library/ctypes ctypes c_size_t10007388
Ref: 2fe910007388
Ref: library/ctypes ctypes c_ssize_t10007462
Ref: 128210007462
Ref: library/ctypes ctypes c_time_t10007566
Ref: 190910007566
Ref: library/ctypes ctypes c_ubyte10007669
Ref: 188410007669
Ref: library/ctypes ctypes c_uint10007883
Ref: 2fe110007883
Ref: library/ctypes ctypes c_uint810008152
Ref: 2fe210008152
Ref: library/ctypes ctypes c_uint1610008277
Ref: 2fe310008277
Ref: library/ctypes ctypes c_uint3210008407
Ref: 2fe410008407
Ref: library/ctypes ctypes c_uint6410008535
Ref: 2fe510008535
Ref: library/ctypes ctypes c_ulong10008668
Ref: 2fe610008668
Ref: library/ctypes ctypes c_ulonglong10008835
Ref: 2fe810008835
Ref: library/ctypes ctypes c_ushort10009016
Ref: 2fdc10009016
Ref: library/ctypes ctypes c_void_p10009185
Ref: 17f810009185
Ref: library/ctypes ctypes c_wchar10009348
Ref: 2fda10009348
Ref: library/ctypes ctypes c_wchar_p10009613
Ref: 17f710009613
Ref: library/ctypes ctypes c_bool10009820
Ref: 2fd810009820
Ref: library/ctypes ctypes HRESULT10010034
Ref: 302410010034
Ref: library/ctypes ctypes py_object10010222
Ref: 148610010222
Node: Structured data types10010599
Ref: library/ctypes ctypes-structured-data-types10010735
Ref: 304e10010735
Ref: library/ctypes structured-data-types10010735
Ref: 304f10010735
Ref: library/ctypes ctypes Union10010800
Ref: 179410010800
Ref: library/ctypes ctypes BigEndianUnion10010898
Ref: 195c10010898
Ref: library/ctypes ctypes LittleEndianUnion10011040
Ref: 195d10011040
Ref: library/ctypes ctypes BigEndianStructure10011188
Ref: 300310011188
Ref: library/ctypes ctypes LittleEndianStructure10011309
Ref: 300410011309
Ref: library/ctypes ctypes Structure10011578
Ref: 1d410011578
Ref: library/ctypes ctypes Structure _fields_10011997
Ref: 2fff10011997
Ref: library/ctypes ctypes Structure _pack_10013584
Ref: 300210013584
Ref: library/ctypes ctypes Structure _align_10013949
Ref: 1d510013949
Ref: library/ctypes ctypes Structure _anonymous_10014245
Ref: 305010014245
Node: Arrays and pointers10016583
Ref: library/ctypes arrays-and-pointers10016685
Ref: 305110016685
Ref: library/ctypes ctypes-arrays-pointers10016685
Ref: 305210016685
Ref: library/ctypes ctypes Array10016746
Ref: 1bbb10016746
Ref: library/ctypes ctypes Array _length_10017249
Ref: 305310017249
Ref: library/ctypes ctypes Array _type_10017478
Ref: 305410017478
Ref: library/ctypes ctypes ARRAY10017676
Ref: 29c10017676
Ref: library/ctypes ctypes _Pointer10017967
Ref: 305510017967
Ref: library/ctypes ctypes _Pointer _type_10018625
Ref: 164910018625
Ref: library/ctypes ctypes _Pointer contents10018695
Ref: 300b10018695
Node: Command-line interface libraries10018885
Ref: library/cmdlinelibs doc10019052
Ref: 305610019052
Ref: library/cmdlinelibs cmdlinelibs10019052
Ref: 305710019052
Ref: library/cmdlinelibs command-line-interface-libraries10019052
Ref: 305810019052
Ref: library/cmdlinelibs translation-repo10019052
Ref: 305910019052
Node: argparse — Parser for command-line options arguments and subcommands10020028
Ref: library/argparse doc10020220
Ref: 305a10020220
Ref: library/argparse argparse-parser-for-command-line-options-arguments-and-subcommands10020220
Ref: 305b10020220
Ref: library/argparse module-argparse10020220
Ref: 610020220
Ref: argparse — Parser for command-line options arguments and subcommands-Footnote-110023284
Node: ArgumentParser objects10023352
Ref: library/argparse argumentparser-objects10023513
Ref: 306010023513
Ref: library/argparse argparse ArgumentParser10023578
Ref: 53c10023578
Node: prog10026332
Ref: library/argparse id110026409
Ref: 306d10026409
Ref: library/argparse prog10026409
Ref: 306110026409
Node: usage10027910
Ref: library/argparse usage10028007
Ref: 306210028007
Node: description10028740
Ref: library/argparse description10028839
Ref: 306310028839
Ref: library/argparse id210028839
Ref: 306e10028839
Node: epilog10029372
Ref: library/argparse epilog10029473
Ref: 306410029473
Node: parents10030241
Ref: library/argparse parents10030346
Ref: 306510030346
Node: formatter_class10031786
Ref: library/argparse formatter-class10031897
Ref: 306610031897
Ref: library/argparse id310031897
Ref: 306f10031897
Ref: library/argparse argparse RawDescriptionHelpFormatter10032113
Ref: 307010032113
Ref: library/argparse argparse RawTextHelpFormatter10032161
Ref: 307110032161
Ref: library/argparse argparse ArgumentDefaultsHelpFormatter10032202
Ref: 19f610032202
Ref: library/argparse argparse MetavarTypeHelpFormatter10032252
Ref: 307210032252
Node: prefix_chars10035718
Ref: library/argparse prefix-chars10035843
Ref: 306710035843
Node: fromfile_prefix_chars10036591
Ref: library/argparse fromfile-prefix-chars10036717
Ref: 306810036717
Node: argument_default10038695
Ref: library/argparse argument-default10038821
Ref: 306910038821
Node: allow_abbrev10039707
Ref: library/argparse allow-abbrev10039828
Ref: dee10039828
Ref: library/argparse id410039828
Ref: 307710039828
Node: conflict_handler10040481
Ref: library/argparse conflict-handler10040594
Ref: 306a10040594
Node: add_help10042135
Ref: library/argparse add-help10042249
Ref: 306b10042249
Node: exit_on_error10043412
Ref: library/argparse exit-on-error10043501
Ref: 306c10043501
Node: The add_argument method10044383
Ref: library/argparse the-add-argument-method10044574
Ref: 307810044574
Ref: library/argparse argparse ArgumentParser add_argument10044647
Ref: 19e10044647
Node: name or flags10046714
Ref: library/argparse id510046802
Ref: 308110046802
Ref: library/argparse name-or-flags10046802
Ref: 307910046802
Node: action10047943
Ref: library/argparse action10048045
Ref: 307a10048045
Ref: library/argparse id610048045
Ref: 308210048045
Node: nargs10054323
Ref: library/argparse id710054417
Ref: 308410054417
Ref: library/argparse nargs10054417
Ref: 16b010054417
Node: const10058623
Ref: library/argparse const10058718
Ref: 307b10058718
Ref: library/argparse id810058718
Ref: 308610058718
Node: default10059980
Ref: library/argparse default10060074
Ref: 307c10060074
Ref: library/argparse id910060074
Ref: 308710060074
Node: type10062518
Ref: library/argparse argparse-type10062614
Ref: 308810062614
Ref: library/argparse type10062614
Ref: 307310062614
Node: choices10065877
Ref: library/argparse choices10065974
Ref: 16ad10065974
Ref: library/argparse id1010065974
Ref: 308a10065974
Node: required10067748
Ref: library/argparse id1110067845
Ref: 308b10067845
Ref: library/argparse required10067845
Ref: 307d10067845
Node: help10068800
Ref: library/argparse help10068897
Ref: 307e10068897
Ref: library/argparse id1210068897
Ref: 308c10068897
Node: metavar10070406
Ref: library/argparse id1310070499
Ref: 308d10070499
Ref: library/argparse metavar10070499
Ref: 307f10070499
Node: dest10072714
Ref: library/argparse dest10072813
Ref: 307410072813
Ref: library/argparse id1410072813
Ref: 308e10072813
Node: deprecated10074440
Ref: library/argparse deprecated10074546
Ref: 308010074546
Ref: library/argparse id1510074546
Ref: 308f10074546
Node: Action classes10075460
Ref: library/argparse action-classes10075553
Ref: 309010075553
Ref: library/argparse argparse Action10075846
Ref: 193210075846
Ref: library/argparse argparse Action __call__10076740
Ref: 309110076740
Ref: library/argparse argparse Action format_usage10078034
Ref: 309210078034
Ref: library/argparse argparse BooleanOptionalAction10078342
Ref: 199610078342
Node: The parse_args method10078932
Ref: library/argparse the-parse-args-method10079116
Ref: 309310079116
Ref: library/argparse argparse ArgumentParser parse_args10079185
Ref: 305e10079185
Node: Option value syntax10080054
Ref: library/argparse option-value-syntax10080157
Ref: 309610080157
Node: Invalid arguments10081554
Ref: library/argparse invalid-arguments10081688
Ref: 309710081688
Node: Arguments containing -10082673
Ref: library/argparse arguments-containing10082826
Ref: 309810082826
Node: Argument abbreviations prefix matching10084907
Ref: library/argparse argument-abbreviations-prefix-matching10085058
Ref: 309910085058
Ref: library/argparse prefix-matching10085058
Ref: ded10085058
Node: Beyond sys argv10085986
Ref: library/argparse args10086135
Ref: 309410086135
Ref: library/argparse beyond-sys-argv10086135
Ref: 309a10086135
Node: The Namespace object10087097
Ref: library/argparse namespace10087199
Ref: 309510087199
Ref: library/argparse the-namespace-object10087199
Ref: 309b10087199
Ref: library/argparse argparse Namespace10087262
Ref: 305f10087262
Node: Other utilities10088390
Ref: library/argparse other-utilities10088564
Ref: 309c10088564
Node: Subcommands10088875
Ref: library/argparse subcommands10088963
Ref: 309d10088963
Ref: library/argparse argparse ArgumentParser add_subparsers10089008
Ref: c3710089008
Node: FileType objects10098375
Ref: library/argparse filetype-objects10098487
Ref: 309e10098487
Ref: library/argparse argparse FileType10098542
Ref: f5210098542
Node: Argument groups10099987
Ref: library/argparse argument-groups10100104
Ref: 309f10100104
Ref: library/argparse argparse ArgumentParser add_argument_group10100157
Ref: 30a010100157
Node: Mutual exclusion10102923
Ref: library/argparse mutual-exclusion10103039
Ref: 30a110103039
Ref: library/argparse argparse ArgumentParser add_mutually_exclusive_group10103094
Ref: 30a210103094
Node: Parser defaults10105801
Ref: library/argparse parser-defaults10105915
Ref: 30a310105915
Ref: library/argparse argparse ArgumentParser set_defaults10105968
Ref: 307610105968
Ref: library/argparse argparse ArgumentParser get_default10107252
Ref: 30a410107252
Node: Printing help10107608
Ref: library/argparse printing-help10107721
Ref: 30a510107721
Ref: library/argparse argparse ArgumentParser print_usage10107950
Ref: 30a610107950
Ref: library/argparse argparse ArgumentParser print_help10108182
Ref: 30a710108182
Ref: library/argparse argparse ArgumentParser format_usage10108536
Ref: 1b5b10108536
Ref: library/argparse argparse ArgumentParser format_help10108715
Ref: 30a810108715
Node: Partial parsing10108928
Ref: library/argparse partial-parsing10109050
Ref: 30a910109050
Ref: library/argparse argparse ArgumentParser parse_known_args10109103
Ref: 30aa10109103
Node: Customizing file parsing10110260
Ref: library/argparse customizing-file-parsing10110384
Ref: 30ab10110384
Ref: library/argparse argparse ArgumentParser convert_arg_line_to_args10110455
Ref: 307510110455
Node: Exiting methods10111348
Ref: library/argparse exiting-methods10111475
Ref: 30ac10111475
Ref: library/argparse argparse ArgumentParser exit10111528
Ref: 30ad10111528
Ref: library/argparse argparse ArgumentParser error10112091
Ref: 30ae10112091
Node: Intermixed parsing10112290
Ref: library/argparse intermixed-parsing10112428
Ref: 30af10112428
Ref: library/argparse argparse ArgumentParser parse_intermixed_args10112487
Ref: b1910112487
Ref: library/argparse argparse ArgumentParser parse_known_intermixed_args10112575
Ref: 30b010112575
Node: Registering custom types or actions10114200
Ref: library/argparse registering-custom-types-or-actions10114314
Ref: 30b110114314
Ref: library/argparse argparse ArgumentParser register10114407
Ref: 308310114407
Node: Exceptions<9>10115875
Ref: library/argparse exceptions10116019
Ref: 30b210116019
Ref: library/argparse argparse ArgumentError10116062
Ref: 30b310116062
Ref: library/argparse argparse ArgumentTypeError10116306
Ref: 308910116306
Node: Argparse Tutorial10116552
Ref: howto/argparse doc10116663
Ref: 30b410116663
Ref: howto/argparse argparse-tutorial10116663
Ref: 305d10116663
Ref: howto/argparse id110116663
Ref: 30b510116663
Node: Concepts10117926
Ref: howto/argparse concepts10118007
Ref: 30b610118007
Node: The basics10120101
Ref: howto/argparse the-basics10120223
Ref: 30b710120223
Node: Introducing Positional arguments10121388
Ref: howto/argparse introducing-positional-arguments10121532
Ref: 30b810121532
Node: Introducing Optional arguments10124808
Ref: howto/argparse introducing-optional-arguments10124985
Ref: 30b910124985
Node: Short options10127969
Ref: howto/argparse short-options10128049
Ref: 30ba10128049
Node: Combining Positional and Optional arguments10128842
Ref: howto/argparse combining-positional-and-optional-arguments10129017
Ref: 30bb10129017
Node: Getting a little more advanced10137095
Ref: howto/argparse getting-a-little-more-advanced10137276
Ref: 30bc10137276
Node: Specifying ambiguous arguments10139282
Ref: howto/argparse id210139407
Ref: 30bd10139407
Ref: howto/argparse specifying-ambiguous-arguments10139407
Ref: 308510139407
Node: Conflicting options10140363
Ref: howto/argparse conflicting-options10140488
Ref: 30be10140488
Node: How to translate the argparse output10143589
Ref: howto/argparse how-to-translate-the-argparse-output10143749
Ref: 30bf10143749
Ref: How to translate the argparse output-Footnote-110145516
Node: Custom type converters10145549
Ref: howto/argparse custom-type-converters10145689
Ref: 30c110145689
Node: Conclusion10147455
Ref: howto/argparse conclusion10147550
Ref: 30c210147550
Ref: howto/argparse-optparse upgrading-optparse-code10147817
Ref: 11f210147817
Node: Migrating optparse code to argparse10147819
Ref: howto/argparse-optparse doc10147930
Ref: 30c310147930
Ref: howto/argparse-optparse migrating-optparse-code10147930
Ref: 30c410147930
Ref: howto/argparse-optparse migrating-optparse-code-to-argparse10147930
Ref: 30c510147930
Ref: howto/argparse-optparse translation-repo10147930
Ref: 30c610147930
Node: optparse — Parser for command line options10150949
Ref: library/optparse doc10151185
Ref: 30cc10151185
Ref: library/optparse module-optparse10151185
Ref: a010151185
Ref: library/optparse optparse-parser-for-command-line-options10151185
Ref: 30cd10151185
Ref: library/optparse translation-repo10151185
Ref: 30ce10151185
Ref: optparse — Parser for command line options-Footnote-110151653
Node: Choosing an argument parsing library10151721
Ref: library/optparse choosing-an-argument-parser10151862
Ref: 305c10151862
Ref: library/optparse choosing-an-argument-parsing-library10151862
Ref: 30cf10151862
Ref: Choosing an argument parsing library-Footnote-110157479
Ref: Choosing an argument parsing library-Footnote-210157519
Ref: Choosing an argument parsing library-Footnote-310157559
Node: Introduction<7>10157607
Ref: library/optparse introduction10157767
Ref: 30d010157767
Node: Background10160155
Ref: library/optparse background10160290
Ref: 30d110160290
Ref: library/optparse optparse-background10160290
Ref: 30d210160290
Node: Terminology10160882
Ref: library/optparse optparse-terminology10160970
Ref: 30d310160970
Ref: library/optparse terminology10160970
Ref: 30d410160970
Node: What are options for?10164808
Ref: library/optparse optparse-what-options-for10164939
Ref: 30d510164939
Ref: library/optparse what-are-options-for10164939
Ref: 30d610164939
Node: What are positional arguments for?10166624
Ref: library/optparse optparse-what-positional-arguments-for10166735
Ref: 30d710166735
Ref: library/optparse what-are-positional-arguments-for10166735
Ref: 30d810166735
Node: Tutorial<2>10168070
Ref: library/optparse optparse-tutorial10168205
Ref: 30d910168205
Ref: library/optparse tutorial10168205
Ref: 30da10168205
Node: Understanding option actions10170792
Ref: library/optparse optparse-understanding-option-actions10170893
Ref: 30df10170893
Ref: library/optparse understanding-option-actions10170893
Ref: 30e010170893
Node: The store action10171464
Ref: library/optparse optparse-store-action10171603
Ref: 30e210171603
Ref: library/optparse the-store-action10171603
Ref: 30e310171603
Node: Handling boolean flag options10173759
Ref: library/optparse handling-boolean-flag-options10173883
Ref: 30e410173883
Ref: library/optparse optparse-handling-boolean-options10173883
Ref: 30e510173883
Node: Other actions10174758
Ref: library/optparse optparse-other-actions10174880
Ref: 30e610174880
Ref: library/optparse other-actions10174880
Ref: 30e710174880
Node: Default values10175334
Ref: library/optparse default-values10175442
Ref: 30eb10175442
Ref: library/optparse optparse-default-values10175442
Ref: 30ec10175442
Node: Generating help10177327
Ref: library/optparse generating-help10177447
Ref: 30ed10177447
Ref: library/optparse optparse-generating-help10177447
Ref: 30ee10177447
Node: Grouping Options10181571
Ref: library/optparse grouping-options10181639
Ref: 30ef10181639
Ref: library/optparse optparse OptionGroup10181970
Ref: 30f010181970
Ref: library/optparse optparse OptionParser get_option_group10185468
Ref: 30f110185468
Node: Printing a version string10185732
Ref: library/optparse optparse-printing-version-string10185865
Ref: 30f210185865
Ref: library/optparse printing-a-version-string10185865
Ref: 30f310185865
Ref: library/optparse optparse OptionParser print_version10186740
Ref: 30f410186740
Ref: library/optparse optparse OptionParser get_version10187114
Ref: 30f610187114
Node: How optparse handles errors10187258
Ref: library/optparse how-optparse-handles-errors10187399
Ref: 30f710187399
Ref: library/optparse optparse-how-optparse-handles-errors10187399
Ref: 30f810187399
Node: Putting it all together10189465
Ref: library/optparse optparse-putting-it-all-together10189572
Ref: 30f910189572
Ref: library/optparse putting-it-all-together10189572
Ref: 30fa10189572
Node: Reference Guide10190485
Ref: library/optparse optparse-reference-guide10190626
Ref: 30e910190626
Ref: library/optparse reference-guide10190626
Ref: 30fb10190626
Node: Creating the parser10190967
Ref: library/optparse creating-the-parser10191068
Ref: 30fc10191068
Ref: library/optparse optparse-creating-parser10191068
Ref: 30fd10191068
Ref: library/optparse optparse OptionParser10191208
Ref: 151c10191208
Node: Populating the parser10194189
Ref: library/optparse optparse-populating-parser10194315
Ref: 30ff10194315
Ref: library/optparse populating-the-parser10194315
Ref: 310010194315
Node: Defining options10195596
Ref: library/optparse defining-options10195720
Ref: 310110195720
Ref: library/optparse optparse-defining-options10195720
Ref: 310210195720
Ref: library/optparse optparse OptionParser add_option10196136
Ref: 30c710196136
Ref: library/optparse optparse Values10198207
Ref: 30c910198207
Node: Option attributes10199430
Ref: library/optparse option-attributes10199556
Ref: 310610199556
Ref: library/optparse optparse-option-attributes10199556
Ref: 310710199556
Ref: library/optparse optparse Option10199613
Ref: 310310199613
Ref: library/optparse optparse Option action10200226
Ref: 30db10200226
Ref: library/optparse optparse Option type10200444
Ref: 30dc10200444
Ref: library/optparse optparse Option dest10200661
Ref: 30dd10200661
Ref: library/optparse optparse Option default10200989
Ref: 310910200989
Ref: library/optparse optparse Option nargs10201183
Ref: 310b10201183
Ref: library/optparse optparse Option const10201411
Ref: 30e810201411
Ref: library/optparse optparse Option choices10201521
Ref: 310c10201521
Ref: library/optparse optparse Option callback10201645
Ref: 310d10201645
Ref: library/optparse optparse Option callback_args10201877
Ref: 310e10201877
Ref: library/optparse optparse Option callback_kwargs10201913
Ref: 310f10201913
Ref: library/optparse optparse Option help10202077
Ref: 30de10202077
Ref: library/optparse optparse Option metavar10202417
Ref: 311010202417
Node: Standard option actions10202622
Ref: library/optparse optparse-standard-option-actions10202753
Ref: 310410202753
Ref: library/optparse standard-option-actions10202753
Ref: 311110202753
Node: Standard option types10210727
Ref: library/optparse optparse-standard-option-types10210858
Ref: 310810210858
Ref: library/optparse standard-option-types10210858
Ref: 311210210858
Node: Parsing arguments10212327
Ref: library/optparse optparse-parsing-arguments10212479
Ref: 310510212479
Ref: library/optparse parsing-arguments10212479
Ref: 311310212479
Ref: library/optparse optparse OptionParser parse_args10212645
Ref: 151d10212645
Node: Querying and manipulating your option parser10214020
Ref: library/optparse optparse-querying-manipulating-option-parser10214176
Ref: 311410214176
Ref: library/optparse querying-and-manipulating-your-option-parser10214176
Ref: 311510214176
Ref: library/optparse optparse OptionParser disable_interspersed_args10214485
Ref: 30c810214485
Ref: library/optparse optparse OptionParser enable_interspersed_args10215264
Ref: 311610215264
Ref: library/optparse optparse OptionParser get_option10215470
Ref: 311710215470
Ref: library/optparse optparse OptionParser has_option10215643
Ref: 311810215643
Ref: library/optparse optparse OptionParser remove_option10215819
Ref: 311910215819
Node: Conflicts between options10216199
Ref: library/optparse conflicts-between-options10216345
Ref: 311a10216345
Ref: library/optparse optparse-conflicts-between-options10216345
Ref: 30fe10216345
Node: Cleanup10218796
Ref: library/optparse cleanup10218911
Ref: 311c10218911
Ref: library/optparse optparse-cleanup10218911
Ref: 311d10218911
Node: Other methods10219324
Ref: library/optparse optparse-other-methods10219405
Ref: 311e10219405
Ref: library/optparse other-methods10219405
Ref: 311f10219405
Ref: library/optparse optparse OptionParser set_usage10219507
Ref: 312010219507
Ref: library/optparse optparse OptionParser print_usage10219796
Ref: 30f510219796
Ref: library/optparse optparse OptionParser get_usage10220132
Ref: 312110220132
Ref: library/optparse optparse OptionParser set_defaults10220270
Ref: 310a10220270
Node: Option Callbacks10221423
Ref: library/optparse option-callbacks10221571
Ref: 312210221571
Ref: library/optparse optparse-option-callbacks10221571
Ref: 30ea10221571
Node: Defining a callback option10222773
Ref: library/optparse defining-a-callback-option10222885
Ref: 312310222885
Ref: library/optparse optparse-defining-callback-option10222885
Ref: 312410222885
Node: How callbacks are called10225080
Ref: library/optparse how-callbacks-are-called10225229
Ref: 312510225229
Ref: library/optparse optparse-how-callbacks-called10225229
Ref: 312610225229
Node: Raising errors in a callback10227817
Ref: library/optparse optparse-raising-errors-in-callback10227975
Ref: 312710227975
Ref: library/optparse raising-errors-in-a-callback10227975
Ref: 312810227975
Node: Callback example 1 trivial callback10228448
Ref: library/optparse callback-example-1-trivial-callback10228619
Ref: 312910228619
Ref: library/optparse optparse-callback-example-110228619
Ref: 312a10228619
Node: Callback example 2 check option order10229067
Ref: library/optparse callback-example-2-check-option-order10229259
Ref: 312b10229259
Ref: library/optparse optparse-callback-example-210229259
Ref: 312c10229259
Node: Callback example 3 check option order generalized10229817
Ref: library/optparse callback-example-3-check-option-order-generalized10230018
Ref: 312d10230018
Ref: library/optparse optparse-callback-example-310230018
Ref: 312e10230018
Node: Callback example 4 check arbitrary condition10230791
Ref: library/optparse callback-example-4-check-arbitrary-condition10230989
Ref: 312f10230989
Ref: library/optparse optparse-callback-example-410230989
Ref: 313010230989
Node: Callback example 5 fixed arguments10231784
Ref: library/optparse callback-example-5-fixed-arguments10231970
Ref: 313110231970
Ref: library/optparse optparse-callback-example-510231970
Ref: 313210231970
Node: Callback example 6 variable arguments10233033
Ref: library/optparse callback-example-6-variable-arguments10233166
Ref: 313310233166
Ref: library/optparse optparse-callback-example-610233166
Ref: 313410233166
Node: Extending optparse10235256
Ref: library/optparse extending-optparse10235403
Ref: 313510235403
Ref: library/optparse optparse-extending-optparse10235403
Ref: 30e110235403
Node: Adding new types10235735
Ref: library/optparse adding-new-types10235833
Ref: 313610235833
Ref: library/optparse optparse-adding-new-types10235833
Ref: 313710235833
Ref: library/optparse optparse Option TYPES10236119
Ref: 313810236119
Ref: library/optparse optparse Option TYPE_CHECKER10236278
Ref: 313910236278
Node: Adding new actions10239288
Ref: library/optparse adding-new-actions10239386
Ref: 313a10239386
Ref: library/optparse optparse-adding-new-actions10239386
Ref: 313b10239386
Ref: library/optparse optparse Option ACTIONS10240474
Ref: 313c10240474
Ref: library/optparse optparse Option STORE_ACTIONS10240550
Ref: 313d10240550
Ref: library/optparse optparse Option TYPED_ACTIONS10240643
Ref: 313e10240643
Ref: library/optparse optparse Option ALWAYS_TYPED_ACTIONS10240736
Ref: 313f10240736
Node: Exceptions<10>10244026
Ref: library/optparse exceptions10244148
Ref: 314010244148
Ref: library/optparse optparse OptionError10244191
Ref: 30ca10244191
Ref: library/optparse optparse OptionConflictError10244332
Ref: 311b10244332
Ref: library/optparse optparse OptionValueError10244460
Ref: 30cb10244460
Ref: library/optparse optparse BadOptionError10244583
Ref: 314110244583
Ref: library/optparse optparse AmbiguousOptionError10244688
Ref: 314210244688
Node: getpass — Portable password input10244801
Ref: library/getpass doc10245027
Ref: 314310245027
Ref: library/getpass getpass-portable-password-input10245027
Ref: 314410245027
Ref: library/getpass module-getpass10245027
Ref: 6210245027
Ref: library/getpass translation-repo10245027
Ref: 314510245027
Ref: library/getpass getpass getpass10245435
Ref: 314610245435
Ref: library/getpass getpass GetPassWarning10246284
Ref: 314710246284
Ref: library/getpass getpass getuser10246412
Ref: 41b10246412
Ref: getpass — Portable password input-Footnote-110247121
Node: fileinput — Iterate over lines from multiple input streams10247188
Ref: library/fileinput doc10247426
Ref: 314810247426
Ref: library/fileinput fileinput-iterate-over-lines-from-multiple-input-streams10247426
Ref: 314910247426
Ref: library/fileinput module-fileinput10247426
Ref: 5b10247426
Ref: library/fileinput translation-repo10247426
Ref: 314a10247426
Ref: library/fileinput fileinput input10249746
Ref: 80510249746
Ref: library/fileinput fileinput filename10250986
Ref: 314b10250986
Ref: library/fileinput fileinput fileno10251142
Ref: 147c10251142
Ref: library/fileinput fileinput lineno10251341
Ref: 314c10251341
Ref: library/fileinput fileinput filelineno10251614
Ref: 314d10251614
Ref: library/fileinput fileinput isfirstline10251880
Ref: 314e10251880
Ref: library/fileinput fileinput isstdin10252032
Ref: 314f10252032
Ref: library/fileinput fileinput nextfile10252175
Ref: 315010252175
Ref: library/fileinput fileinput close10252715
Ref: 315110252715
Ref: library/fileinput fileinput FileInput10252886
Ref: 73a10252886
Ref: library/fileinput fileinput hook_compressed10255579
Ref: 80610255579
Ref: library/fileinput fileinput hook_encoded10256380
Ref: cc610256380
Ref: fileinput — Iterate over lines from multiple input streams-Footnote-110256982
Node: curses — Terminal handling for character-cell displays10257051
Ref: library/curses doc10257310
Ref: 315210257310
Ref: library/curses curses-terminal-handling-for-character-cell-displays10257310
Ref: 315310257310
Ref: library/curses module-curses10257310
Ref: 2b10257310
Ref: library/curses translation-repo10257310
Ref: 315410257310
Ref: curses — Terminal handling for character-cell displays-Footnote-110259047
Node: Functions<6>10259110
Ref: library/curses curses-functions10259238
Ref: 315610259238
Ref: library/curses functions10259238
Ref: 315710259238
Ref: library/curses curses error10259335
Ref: 315810259335
Ref: library/curses curses baudrate10259698
Ref: 315a10259698
Ref: library/curses curses beep10260050
Ref: 315b10260050
Ref: library/curses curses can_change_color10260116
Ref: 315c10260116
Ref: library/curses curses cbreak10260288
Ref: 315d10260288
Ref: library/curses curses color_content10260759
Ref: 7f610260759
Ref: library/curses curses color_pair10261142
Ref: 315f10261142
Ref: library/curses curses curs_set10261529
Ref: 316310261529
Ref: library/curses curses def_prog_mode10261957
Ref: 316410261957
Ref: library/curses curses def_shell_mode10262285
Ref: 316610262285
Ref: library/curses curses delay_output10262631
Ref: 316810262631
Ref: library/curses curses doupdate10262721
Ref: 316910262721
Ref: library/curses curses echo10263539
Ref: 316d10263539
Ref: library/curses curses endwin10263675
Ref: 316e10263675
Ref: library/curses curses erasechar10263778
Ref: 316f10263778
Ref: library/curses curses filter10264046
Ref: 317010264046
Ref: library/curses curses flash10264650
Ref: 317110264650
Ref: library/curses curses flushinp10264913
Ref: 317210264913
Ref: library/curses curses getmouse10265099
Ref: 317310265099
Ref: library/curses curses getsyx10266100
Ref: 317d10266100
Ref: library/curses curses getwin10266311
Ref: 317f10266311
Ref: library/curses curses has_colors10266566
Ref: 318110266566
Ref: library/curses curses has_extended_color_support10266698
Ref: 7fa10266698
Ref: library/curses curses has_ic10267084
Ref: 318210267084
Ref: library/curses curses has_il10267340
Ref: 318310267340
Ref: library/curses curses has_key10267637
Ref: 318410267637
Ref: library/curses curses halfdelay10267791
Ref: 318510267791
Ref: library/curses curses init_color10268229
Ref: 7f710268229
Ref: library/curses curses init_pair10268874
Ref: 7f810268874
Ref: library/curses curses initscr10269595
Ref: 16a710269595
Ref: library/curses curses is_term_resized10269870
Ref: 318910269870
Ref: library/curses curses isendwin10270041
Ref: 318a10270041
Ref: library/curses curses keyname10270199
Ref: 318b10270199
Ref: library/curses curses killchar10270730
Ref: 318c10270730
Ref: library/curses curses longname10271001
Ref: 318d10271001
Ref: library/curses curses meta10271276
Ref: 318e10271276
Ref: library/curses curses mouseinterval10271433
Ref: 318f10271433
Ref: library/curses curses mousemask10271740
Ref: 319010271740
Ref: library/curses curses napms10272160
Ref: 16a610272160
Ref: library/curses curses newpad10272228
Ref: 319110272228
Ref: library/curses curses newwin10273316
Ref: 319210273316
Ref: library/curses curses nl10273683
Ref: 319310273683
Ref: library/curses curses nocbreak10273898
Ref: 318610273898
Ref: library/curses curses noecho10274019
Ref: 319410274019
Ref: library/curses curses nonl10274118
Ref: 319510274118
Ref: library/curses curses noqiflush10274611
Ref: 319610274611
Ref: library/curses curses noraw10275001
Ref: 319710275001
Ref: library/curses curses pair_content10275116
Ref: 7f910275116
Ref: library/curses curses pair_number10275342
Ref: 316210275342
Ref: library/curses curses putp10275534
Ref: 319810275534
Ref: library/curses curses qiflush10275773
Ref: 319910275773
Ref: library/curses curses raw10276039
Ref: 315e10276039
Ref: library/curses curses reset_prog_mode10276281
Ref: 316510276281
Ref: library/curses curses reset_shell_mode10276429
Ref: 316710276429
Ref: library/curses curses resetty10276577
Ref: 319a10276577
Ref: library/curses curses resize_term10276719
Ref: 16af10276719
Ref: library/curses curses resizeterm10277251
Ref: 16ae10277251
Ref: library/curses curses savetty10277524
Ref: 319b10277524
Ref: library/curses curses get_escdelay10277659
Ref: 8f910277659
Ref: library/curses curses set_escdelay10277785
Ref: 8fa10277785
Ref: library/curses curses get_tabsize10278083
Ref: 8fb10278083
Ref: library/curses curses set_tabsize10278207
Ref: 8fc10278207
Ref: library/curses curses setsyx10278420
Ref: 319c10278420
Ref: library/curses curses setupterm10278590
Ref: 319d10278590
Ref: library/curses curses start_color10279007
Ref: 319e10279007
Ref: library/curses curses termattrs10279683
Ref: 31a110279683
Ref: library/curses curses termname10279913
Ref: 31a210279913
Ref: library/curses curses tigetflag10280062
Ref: 31a310280062
Ref: library/curses curses tigetnum10280378
Ref: 31a410280378
Ref: library/curses curses tigetstr10280694
Ref: 31a510280694
Ref: library/curses curses tparm10281004
Ref: 31a610281004
Ref: library/curses curses typeahead10281341
Ref: 31a710281341
Ref: library/curses curses unctrl10281934
Ref: 31a810281934
Ref: library/curses curses ungetch10282215
Ref: 31a910282215
Ref: library/curses curses update_lines_cols10282392
Ref: e1c10282392
Ref: library/curses curses unget_wch10282585
Ref: 10dc10282585
Ref: library/curses curses ungetmouse10282806
Ref: 31aa10282806
Ref: library/curses curses use_env10282972
Ref: 31ab10282972
Ref: library/curses curses use_default_colors10283482
Ref: 318710283482
Ref: library/curses curses wrapper10283915
Ref: a8f10283915
Node: Window Objects10284741
Ref: library/curses curses-window-objects10284890
Ref: 318810284890
Ref: library/curses window-objects10284890
Ref: 31ac10284890
Ref: library/curses curses window10284939
Ref: 10d910284939
Ref: library/curses curses window addch10285106
Ref: 31ad10285106
Ref: library/curses curses window addnstr10285709
Ref: 31ae10285709
Ref: library/curses curses window addstr10285968
Ref: 316b10285968
Ref: library/curses curses window attroff10286961
Ref: 31af10286961
Ref: library/curses curses window attron10287106
Ref: 31b010287106
Ref: library/curses curses window attrset10287245
Ref: 31b110287245
Ref: library/curses curses window bkgd10287393
Ref: 31b210287393
Ref: library/curses curses window bkgdset10287838
Ref: 31b310287838
Ref: library/curses curses window border10288404
Ref: 31b410288404
Ref: library/curses curses window box10290412
Ref: 31bb10290412
Ref: library/curses curses window chgat10290640
Ref: 31bc10290640
Ref: library/curses curses window clear10291264
Ref: 31be10291264
Ref: library/curses curses window clearok10291419
Ref: 31c010291419
Ref: library/curses curses window clrtobot10291564
Ref: 31c110291564
Ref: library/curses curses window clrtoeol10291761
Ref: 31c210291761
Ref: library/curses curses window cursyncup10291841
Ref: 31c310291841
Ref: library/curses curses window delch10292009
Ref: 31c410292009
Ref: library/curses curses window deleteln10292088
Ref: 31c510292088
Ref: library/curses curses window derwin10292212
Ref: 31c610292212
Ref: library/curses curses window echochar10292610
Ref: 31c810292610
Ref: library/curses curses window enclose10292764
Ref: 1a3710292764
Ref: library/curses curses window encoding10293184
Ref: 10da10293184
Ref: library/curses curses window erase10293565
Ref: 31bf10293565
Ref: library/curses curses window getbegyx10293618
Ref: 31c910293618
Ref: library/curses curses window getbkgd10293721
Ref: 31ca10293721
Ref: library/curses curses window getch10293836
Ref: 164710293836
Ref: library/curses curses window get_wch10294156
Ref: 10db10294156
Ref: library/curses curses window getkey10294424
Ref: 31cb10294424
Ref: library/curses curses window getmaxyx10294732
Ref: 31cc10294732
Ref: library/curses curses window getparyx10294837
Ref: 31cd10294837
Ref: library/curses curses window getstr10295041
Ref: 31ce10295041
Ref: library/curses curses window getyx10295257
Ref: 31cf10295257
Ref: library/curses curses window hline10295398
Ref: 31d010295398
Ref: library/curses curses window idcok10295584
Ref: 31d110295584
Ref: library/curses curses window idlok10295930
Ref: 31d210295930
Ref: library/curses curses window immedok10296118
Ref: 31d310296118
Ref: library/curses curses window inch10296467
Ref: 31d410296467
Ref: library/curses curses window insch10296655
Ref: 31d510296655
Ref: library/curses curses window insdelln10296869
Ref: 31d610296869
Ref: library/curses curses window insertln10297248
Ref: 31d710297248
Ref: library/curses curses window insnstr10297378
Ref: 31d810297378
Ref: library/curses curses window insstr10297891
Ref: 31d910297891
Ref: library/curses curses window instr10298310
Ref: 31da10298310
Ref: library/curses curses window is_linetouched10298699
Ref: 31db10298699
Ref: library/curses curses window is_wintouched10298982
Ref: 31dc10298982
Ref: library/curses curses window keypad10299162
Ref: 31dd10299162
Ref: library/curses curses window leaveok10299427
Ref: 317e10299427
Ref: library/curses curses window move10299778
Ref: 31de10299778
Ref: library/curses curses window mvderwin10299861
Ref: 31df10299861
Ref: library/curses curses window mvwin10300138
Ref: 31e010300138
Ref: library/curses curses window nodelay10300254
Ref: 31e110300254
Ref: library/curses curses window notimeout10300363
Ref: 31e210300363
Ref: library/curses curses window noutrefresh10300627
Ref: 316a10300627
Ref: library/curses curses window overlay10300901
Ref: 31e310300901
Ref: library/curses curses window overwrite10301543
Ref: 31e410301543
Ref: library/curses curses window putwin10302188
Ref: 318010302188
Ref: library/curses curses window redrawln10302394
Ref: 31e510302394
Ref: library/curses curses window redrawwin10302600
Ref: 31e610302600
Ref: library/curses curses window refresh10302746
Ref: 316c10302746
Ref: library/curses curses window resize10303767
Ref: 31e710303767
Ref: library/curses curses window scroll10304119
Ref: 31e810304119
Ref: library/curses curses window scrollok10304227
Ref: 31e910304227
Ref: library/curses curses window setscrreg10304763
Ref: 31ea10304763
Ref: library/curses curses window standend10304932
Ref: 31eb10304932
Ref: library/curses curses window standout10305083
Ref: 31ec10305083
Ref: library/curses curses window subpad10305153
Ref: 31ed10305153
Ref: library/curses curses window subwin10305392
Ref: 31c710305392
Ref: library/curses curses window syncdown10305750
Ref: 31ee10305750
Ref: library/curses curses window syncok10305996
Ref: 31ef10305996
Ref: library/curses curses window syncup10306159
Ref: 31f010306159
Ref: library/curses curses window timeout10306285
Ref: 31f110306285
Ref: library/curses curses window touchline10306781
Ref: 31bd10306781
Ref: library/curses curses window touchwin10307089
Ref: 31f210307089
Ref: library/curses curses window untouchwin10307214
Ref: 31f310307214
Ref: library/curses curses window vline10307347
Ref: 18a110307347
Ref: Window Objects-Footnote-110307606
Node: Constants<6>10307649
Ref: library/curses constants10307777
Ref: 31f410307777
Ref: library/curses curses ERR10307877
Ref: 31f510307877
Ref: library/curses curses OK10308022
Ref: 31f610308022
Ref: library/curses curses version10308165
Ref: 31f710308165
Ref: library/curses curses ncurses_version10308260
Ref: 9f210308260
Ref: library/curses curses COLORS10308679
Ref: 319f10308679
Ref: library/curses curses COLOR_PAIRS10308835
Ref: 31a010308835
Ref: library/curses curses COLS10309001
Ref: e1e10309001
Ref: library/curses curses LINES10309261
Ref: e1d10309261
Ref: library/curses curses A_ALTCHARSET10309814
Ref: 31f810309814
Ref: library/curses curses A_BLINK10309918
Ref: 31f910309918
Ref: library/curses curses A_BOLD10310017
Ref: 31fa10310017
Ref: library/curses curses A_DIM10310115
Ref: 31fb10310115
Ref: library/curses curses A_INVIS10310215
Ref: 31fc10310215
Ref: library/curses curses A_ITALIC10310329
Ref: 31fd10310329
Ref: library/curses curses A_NORMAL10310430
Ref: 315910310430
Ref: library/curses curses A_PROTECT10310537
Ref: 31fe10310537
Ref: library/curses curses A_REVERSE10310641
Ref: 316110310641
Ref: library/curses curses A_STANDOUT10310783
Ref: 316010310783
Ref: library/curses curses A_UNDERLINE10310857
Ref: 31ff10310857
Ref: library/curses curses A_HORIZONTAL10310932
Ref: 320010310932
Ref: library/curses curses A_LEFT10311027
Ref: 320110311027
Ref: library/curses curses A_LOW10311130
Ref: 320210311130
Ref: library/curses curses A_RIGHT10311235
Ref: 320310311235
Ref: library/curses curses A_TOP10311338
Ref: 320410311338
Ref: library/curses curses A_VERTICAL10311428
Ref: 320510311428
Ref: library/curses curses A_ATTRIBUTES10311818
Ref: 320610311818
Ref: library/curses curses A_CHARTEXT10311929
Ref: 320710311929
Ref: library/curses curses A_COLOR10312050
Ref: 320810312050
Ref: library/curses curses KEY_MIN10312498
Ref: 320910312498
Ref: library/curses curses KEY_BREAK10312610
Ref: 320a10312610
Ref: library/curses curses KEY_DOWN10312724
Ref: 320b10312724
Ref: library/curses curses KEY_UP10312825
Ref: 320c10312825
Ref: library/curses curses KEY_LEFT10312928
Ref: 320d10312928
Ref: library/curses curses KEY_RIGHT10313032
Ref: 320e10313032
Ref: library/curses curses KEY_HOME10313135
Ref: 320f10313135
Ref: library/curses curses KEY_BACKSPACE10313240
Ref: 321010313240
Ref: library/curses curses KEY_F010313339
Ref: 321110313339
Ref: library/curses curses KEY_Fn10313515
Ref: 321210313515
Ref: library/curses curses KEY_DL10313633
Ref: 321310313633
Ref: library/curses curses KEY_IL10313737
Ref: 321410313737
Ref: library/curses curses KEY_DC10313841
Ref: 321510313841
Ref: library/curses curses KEY_IC10313950
Ref: 321610313950
Ref: library/curses curses KEY_EIC10314076
Ref: 321710314076
Ref: library/curses curses KEY_CLEAR10314192
Ref: 321810314192
Ref: library/curses curses KEY_EOS10314295
Ref: 321910314295
Ref: library/curses curses KEY_EOL10314410
Ref: 321a10314410
Ref: library/curses curses KEY_SF10314522
Ref: 321b10314522
Ref: library/curses curses KEY_SR10314636
Ref: 321c10314636
Ref: library/curses curses KEY_NPAGE10314764
Ref: 321d10314764
Ref: library/curses curses KEY_PPAGE10314866
Ref: 321e10314866
Ref: library/curses curses KEY_STAB10314971
Ref: 321f10314971
Ref: library/curses curses KEY_CTAB10315071
Ref: 322010315071
Ref: library/curses curses KEY_CATAB10315174
Ref: 322110315174
Ref: library/curses curses KEY_ENTER10315281
Ref: 322210315281
Ref: library/curses curses KEY_SRESET10315401
Ref: 322310315401
Ref: library/curses curses KEY_RESET10315526
Ref: 322410315526
Ref: library/curses curses KEY_PRINT10315651
Ref: 322510315651
Ref: library/curses curses KEY_LL10315746
Ref: 322610315746
Ref: library/curses curses KEY_A110315871
Ref: 322710315871
Ref: library/curses curses KEY_A310315984
Ref: 322810315984
Ref: library/curses curses KEY_B210316098
Ref: 322910316098
Ref: library/curses curses KEY_C110316207
Ref: 322a10316207
Ref: library/curses curses KEY_C310316320
Ref: 322b10316320
Ref: library/curses curses KEY_BTAB10316436
Ref: 322c10316436
Ref: library/curses curses KEY_BEG10316536
Ref: 322d10316536
Ref: library/curses curses KEY_CANCEL10316647
Ref: 322e10316647
Ref: library/curses curses KEY_CLOSE10316745
Ref: 322f10316745
Ref: library/curses curses KEY_COMMAND10316826
Ref: 323010316826
Ref: library/curses curses KEY_COPY10316918
Ref: 323110316918
Ref: library/curses curses KEY_CREATE10317017
Ref: 323210317017
Ref: library/curses curses KEY_END10317113
Ref: 323310317113
Ref: library/curses curses KEY_EXIT10317210
Ref: 323410317210
Ref: library/curses curses KEY_FIND10317307
Ref: 323510317307
Ref: library/curses curses KEY_HELP10317404
Ref: 323610317404
Ref: library/curses curses KEY_MARK10317501
Ref: 323710317501
Ref: library/curses curses KEY_MESSAGE10317582
Ref: 323810317582
Ref: library/curses curses KEY_MOVE10317668
Ref: 323910317668
Ref: library/curses curses KEY_NEXT10317765
Ref: 323a10317765
Ref: library/curses curses KEY_OPEN10317862
Ref: 323b10317862
Ref: library/curses curses KEY_OPTIONS10317943
Ref: 323c10317943
Ref: library/curses curses KEY_PREVIOUS10318013
Ref: 323d10318013
Ref: library/curses curses KEY_REDO10318107
Ref: 323e10318107
Ref: library/curses curses KEY_REFERENCE10318188
Ref: 323f10318188
Ref: library/curses curses KEY_REFRESH10318266
Ref: 324010318266
Ref: library/curses curses KEY_REPLACE10318336
Ref: 324110318336
Ref: library/curses curses KEY_RESTART10318406
Ref: 324210318406
Ref: library/curses curses KEY_RESUME10318494
Ref: 324310318494
Ref: library/curses curses KEY_SAVE10318591
Ref: 324410318591
Ref: library/curses curses KEY_SBEG10318688
Ref: 324510318688
Ref: library/curses curses KEY_SCANCEL10318788
Ref: 324610318788
Ref: library/curses curses KEY_SCOMMAND10318865
Ref: 324710318865
Ref: library/curses curses KEY_SCOPY10318960
Ref: 324810318960
Ref: library/curses curses KEY_SCREATE10319048
Ref: 324910319048
Ref: library/curses curses KEY_SDC10319140
Ref: 324a10319140
Ref: library/curses curses KEY_SDL10319252
Ref: 324b10319252
Ref: library/curses curses KEY_SELECT10319367
Ref: 324c10319367
Ref: library/curses curses KEY_SEND10319464
Ref: 324d10319464
Ref: library/curses curses KEY_SEOL10319568
Ref: 324e10319568
Ref: library/curses curses KEY_SEXIT10319680
Ref: 324f10319680
Ref: library/curses curses KEY_SFIND10319785
Ref: 325010319785
Ref: library/curses curses KEY_SHELP10319890
Ref: 325110319890
Ref: library/curses curses KEY_SHOME10319995
Ref: 325210319995
Ref: library/curses curses KEY_SIC10320098
Ref: 325310320098
Ref: library/curses curses KEY_SLEFT10320206
Ref: 325410320206
Ref: library/curses curses KEY_SMESSAGE10320300
Ref: 325510320300
Ref: library/curses curses KEY_SMOVE10320395
Ref: 325610320395
Ref: library/curses curses KEY_SNEXT10320500
Ref: 325710320500
Ref: library/curses curses KEY_SOPTIONS10320588
Ref: 325810320588
Ref: library/curses curses KEY_SPREVIOUS10320666
Ref: 325910320666
Ref: library/curses curses KEY_SPRINT10320759
Ref: 325a10320759
Ref: library/curses curses KEY_SREDO10320864
Ref: 325b10320864
Ref: library/curses curses KEY_SREPLACE10320952
Ref: 325c10320952
Ref: library/curses curses KEY_SRIGHT10321048
Ref: 325d10321048
Ref: library/curses curses KEY_SRSUME10321160
Ref: 325e10321160
Ref: library/curses curses KEY_SSAVE10321266
Ref: 325f10321266
Ref: library/curses curses KEY_SSUSPEND10321354
Ref: 326010321354
Ref: library/curses curses KEY_SUNDO10321449
Ref: 326110321449
Ref: library/curses curses KEY_SUSPEND10321537
Ref: 326210321537
Ref: library/curses curses KEY_UNDO10321623
Ref: 326310321623
Ref: library/curses curses KEY_MOUSE10321721
Ref: 317410321721
Ref: library/curses curses KEY_RESIZE10321839
Ref: 326410321839
Ref: library/curses curses KEY_MAX10321950
Ref: 326510321950
Ref: library/curses curses-acs-codes10323134
Ref: 326610323134
Ref: library/curses curses ACS_BBSS10323711
Ref: 326710323711
Ref: library/curses curses ACS_BLOCK10323839
Ref: 326810323839
Ref: library/curses curses ACS_BOARD10323947
Ref: 326910323947
Ref: library/curses curses ACS_BSBS10324052
Ref: 326a10324052
Ref: library/curses curses ACS_BSSB10324176
Ref: 326b10324176
Ref: library/curses curses ACS_BSSS10324302
Ref: 326c10324302
Ref: library/curses curses ACS_BTEE10324418
Ref: 326d10324418
Ref: library/curses curses ACS_BULLET10324502
Ref: 326e10324502
Ref: library/curses curses ACS_CKBOARD10324569
Ref: 326f10324569
Ref: library/curses curses ACS_DARROW10324653
Ref: 327010324653
Ref: library/curses curses ACS_DEGREE10324733
Ref: 327110324733
Ref: library/curses curses ACS_DIAMOND10324807
Ref: 327210324807
Ref: library/curses curses ACS_GEQUAL10324875
Ref: 327310324875
Ref: library/curses curses ACS_HLINE10324977
Ref: 31b610324977
Ref: library/curses curses ACS_LANTERN10325065
Ref: 327410325065
Ref: library/curses curses ACS_LARROW10325140
Ref: 327510325140
Ref: library/curses curses ACS_LEQUAL10325211
Ref: 327610325211
Ref: library/curses curses ACS_LLCORNER10325293
Ref: 31b910325293
Ref: library/curses curses ACS_LRCORNER10325376
Ref: 31ba10325376
Ref: library/curses curses ACS_LTEE10325476
Ref: 327710325476
Ref: library/curses curses ACS_NEQUAL10325558
Ref: 327810325558
Ref: library/curses curses ACS_PI10325647
Ref: 327910325647
Ref: library/curses curses ACS_PLMINUS10325732
Ref: 327a10325732
Ref: library/curses curses ACS_PLUS10325827
Ref: 327b10325827
Ref: library/curses curses ACS_RARROW10325914
Ref: 327c10325914
Ref: library/curses curses ACS_RTEE10326002
Ref: 327d10326002
Ref: library/curses curses ACS_S110326099
Ref: 327e10326099
Ref: library/curses curses ACS_S310326200
Ref: 327f10326200
Ref: library/curses curses ACS_S710326301
Ref: 328010326301
Ref: library/curses curses ACS_S910326402
Ref: 328110326402
Ref: library/curses curses ACS_SBBS10326505
Ref: 328210326505
Ref: library/curses curses ACS_SBSB10326632
Ref: 328310326632
Ref: library/curses curses ACS_SBSS10326754
Ref: 328410326754
Ref: library/curses curses ACS_SSBB10326872
Ref: 328510326872
Ref: library/curses curses ACS_SSBS10326998
Ref: 328610326998
Ref: library/curses curses ACS_SSSB10327117
Ref: 328710327117
Ref: library/curses curses ACS_SSSS10327234
Ref: 328810327234
Ref: library/curses curses ACS_STERLING10327348
Ref: 328910327348
Ref: library/curses curses ACS_TTEE10327439
Ref: 328a10327439
Ref: library/curses curses ACS_UARROW10327520
Ref: 328b10327520
Ref: library/curses curses ACS_ULCORNER10327589
Ref: 31b710327589
Ref: library/curses curses ACS_URCORNER10327667
Ref: 31b810327667
Ref: library/curses curses ACS_VLINE10327763
Ref: 31b510327763
Ref: library/curses curses BUTTONn_PRESSED10328143
Ref: 317510328143
Ref: library/curses curses BUTTONn_RELEASED10328288
Ref: 317610328288
Ref: library/curses curses BUTTONn_CLICKED10328432
Ref: 317710328432
Ref: library/curses curses BUTTONn_DOUBLE_CLICKED10328553
Ref: 317810328553
Ref: library/curses curses BUTTONn_TRIPLE_CLICKED10328665
Ref: 317910328665
Ref: library/curses curses BUTTON_SHIFT10328797
Ref: 317a10328797
Ref: library/curses curses BUTTON_CTRL10328957
Ref: 317b10328957
Ref: library/curses curses BUTTON_ALT10329119
Ref: 317c10329119
Ref: library/curses curses COLOR_BLACK10329564
Ref: 328c10329564
Ref: library/curses curses COLOR_BLUE10329650
Ref: 328d10329650
Ref: library/curses curses COLOR_CYAN10329747
Ref: 328e10329747
Ref: library/curses curses COLOR_GREEN10329848
Ref: 328f10329848
Ref: library/curses curses COLOR_MAGENTA10329916
Ref: 329010329916
Ref: library/curses curses COLOR_RED10330018
Ref: 329110330018
Ref: library/curses curses COLOR_WHITE10330097
Ref: 329210330097
Ref: library/curses curses COLOR_YELLOW10330165
Ref: 329310330165
Node: curses textpad — Text input widget for curses programs10330225
Ref: library/curses curses-textpad-text-input-widget-for-curses-programs10330471
Ref: 329410330471
Ref: library/curses module-curses textpad10330471
Ref: 2e10330471
Ref: library/curses curses textpad rectangle10331050
Ref: 329610331050
Node: Textbox objects10331773
Ref: library/curses curses-textpad-objects10331881
Ref: 329710331881
Ref: library/curses textbox-objects10331881
Ref: 329810331881
Ref: library/curses curses textpad Textbox10331995
Ref: 329510331995
Ref: library/curses curses textpad Textbox edit10332467
Ref: 329a10332467
Ref: library/curses curses textpad Textbox do_command10333038
Ref: 329b10333038
Ref: library/curses curses textpad Textbox gather10336768
Ref: 329c10336768
Ref: library/curses curses textpad Textbox stripspaces10336961
Ref: 329910336961
Node: curses ascii — Utilities for ASCII characters10337372
Ref: library/curses ascii doc10337613
Ref: 329d10337613
Ref: library/curses ascii curses-ascii-utilities-for-ascii-characters10337613
Ref: 329e10337613
Ref: library/curses ascii module-curses ascii10337613
Ref: 2c10337613
Ref: library/curses ascii translation-repo10337613
Ref: 329f10337613
Ref: library/curses ascii curses ascii NUL10338201
Ref: 32a010338201
Ref: library/curses ascii curses ascii SOH10338239
Ref: 32a110338239
Ref: library/curses ascii curses ascii STX10338323
Ref: 32a210338323
Ref: library/curses ascii curses ascii ETX10338385
Ref: 32a310338385
Ref: library/curses ascii curses ascii EOT10338445
Ref: 32a410338445
Ref: library/curses ascii curses ascii ENQ10338513
Ref: 32a510338513
Ref: library/curses ascii curses ascii ACK10338610
Ref: 32a610338610
Ref: library/curses ascii curses ascii BEL10338674
Ref: 32a710338674
Ref: library/curses ascii curses ascii BS10338727
Ref: 32a810338727
Ref: library/curses ascii curses ascii TAB10338784
Ref: 32a910338784
Ref: library/curses ascii curses ascii HT10338836
Ref: 32aa10338836
Ref: library/curses ascii curses ascii LF10338932
Ref: 32ab10338932
Ref: library/curses ascii curses ascii NL10338989
Ref: 32ac10338989
Ref: library/curses ascii curses ascii VT10339078
Ref: 32ad10339078
Ref: library/curses ascii curses ascii FF10339138
Ref: 32ae10339138
Ref: library/curses ascii curses ascii CR10339195
Ref: 32af10339195
Ref: library/curses ascii curses ascii SO10339258
Ref: 32b010339258
Ref: library/curses ascii curses ascii SI10339346
Ref: 32b110339346
Ref: library/curses ascii curses ascii DLE10339432
Ref: 32b210339432
Ref: library/curses ascii curses ascii DC110339497
Ref: 32b310339497
Ref: library/curses ascii curses ascii DC210339567
Ref: 32b410339567
Ref: library/curses ascii curses ascii DC310339657
Ref: 32b510339657
Ref: library/curses ascii curses ascii DC410339728
Ref: 32b610339728
Ref: library/curses ascii curses ascii NAK10339793
Ref: 32b710339793
Ref: library/curses ascii curses ascii SYN10339866
Ref: 32b810339866
Ref: library/curses ascii curses ascii ETB10339931
Ref: 32b910339931
Ref: library/curses ascii curses ascii CAN10340002
Ref: 32ba10340002
Ref: library/curses ascii curses ascii EM10340057
Ref: 32bb10340057
Ref: library/curses ascii curses ascii SUB10340118
Ref: 32bc10340118
Ref: library/curses ascii curses ascii ESC10340177
Ref: 32bd10340177
Ref: library/curses ascii curses ascii FS10340232
Ref: 32be10340232
Ref: library/curses ascii curses ascii GS10340294
Ref: 32bf10340294
Ref: library/curses ascii curses ascii RS10340357
Ref: 32c010340357
Ref: library/curses ascii curses ascii US10340444
Ref: 32c110340444
Ref: library/curses ascii curses ascii SP10340506
Ref: 32c210340506
Ref: library/curses ascii curses ascii DEL10340559
Ref: 32c310340559
Ref: library/curses ascii curses ascii isalnum10340857
Ref: 32c410340857
Ref: library/curses ascii curses ascii isalpha10341004
Ref: 32c510341004
Ref: library/curses ascii curses ascii isascii10341149
Ref: 32c610341149
Ref: library/curses ascii curses ascii isblank10341258
Ref: 32c710341258
Ref: library/curses ascii curses ascii iscntrl10341371
Ref: 32c810341371
Ref: library/curses ascii curses ascii isdigit10341497
Ref: 32c910341497
Ref: library/curses ascii curses ascii isgraph10341661
Ref: 32ca10341661
Ref: library/curses ascii curses ascii islower10341762
Ref: 32cb10341762
Ref: library/curses ascii curses ascii isprint10341850
Ref: 32cc10341850
Ref: library/curses ascii curses ascii ispunct10341954
Ref: 32cd10341954
Ref: library/curses ascii curses ascii isspace10342097
Ref: 32ce10342097
Ref: library/curses ascii curses ascii isupper10342265
Ref: 32cf10342265
Ref: library/curses ascii curses ascii isxdigit10342349
Ref: 32d010342349
Ref: library/curses ascii curses ascii isctrl10342492
Ref: 32d110342492
Ref: library/curses ascii curses ascii ismeta10342601
Ref: 32d210342601
Ref: library/curses ascii curses ascii ascii10343201
Ref: 32d310343201
Ref: library/curses ascii curses ascii ctrl10343308
Ref: 32d410343308
Ref: library/curses ascii curses ascii alt10343476
Ref: 32d510343476
Ref: library/curses ascii curses ascii unctrl10343748
Ref: 32d610343748
Ref: library/curses ascii curses ascii controlnames10344303
Ref: 32d710344303
Ref: curses ascii — Utilities for ASCII characters-Footnote-110344585
Node: curses panel — A panel stack extension for curses10344657
Ref: library/curses panel doc10344896
Ref: 32d810344896
Ref: library/curses panel curses-panel-a-panel-stack-extension-for-curses10344896
Ref: 32d910344896
Ref: library/curses panel module-curses panel10344896
Ref: 2d10344896
Ref: library/curses panel translation-repo10344896
Ref: 32da10344896
Node: Functions<7>10345372
Ref: library/curses panel cursespanel-functions10345494
Ref: 32db10345494
Ref: library/curses panel functions10345494
Ref: 32dc10345494
Ref: library/curses panel curses panel bottom_panel10345597
Ref: 32dd10345597
Ref: library/curses panel curses panel new_panel10345692
Ref: 32de10345692
Ref: library/curses panel curses panel top_panel10345994
Ref: 32df10345994
Ref: library/curses panel curses panel update_panels10346083
Ref: 32e010346083
Node: Panel Objects10346294
Ref: library/curses panel curses-panel-objects10346416
Ref: 32e110346416
Ref: library/curses panel panel-objects10346416
Ref: 32e210346416
Ref: library/curses panel curses panel Panel above10346770
Ref: 32e310346770
Ref: library/curses panel curses panel Panel below10346847
Ref: 32e410346847
Ref: library/curses panel curses panel Panel bottom10346924
Ref: 32e510346924
Ref: library/curses panel curses panel Panel hidden10347002
Ref: 32e610347002
Ref: library/curses panel curses panel Panel hide10347122
Ref: 32e710347122
Ref: library/curses panel curses panel Panel move10347256
Ref: 32e810347256
Ref: library/curses panel curses panel Panel replace10347348
Ref: 32e910347348
Ref: library/curses panel curses panel Panel set_userptr10347452
Ref: 32ea10347452
Ref: library/curses panel curses panel Panel show10347646
Ref: 32eb10347646
Ref: library/curses panel curses panel Panel top10347729
Ref: 32ec10347729
Ref: library/curses panel curses panel Panel userptr10347797
Ref: 32ed10347797
Ref: library/curses panel curses panel Panel window10347912
Ref: 32ee10347912
Node: cmd — Support for line-oriented command interpreters10348000
Ref: library/cmd doc10348183
Ref: 32ef10348183
Ref: library/cmd cmd-support-for-line-oriented-command-interpreters10348183
Ref: 32f010348183
Ref: library/cmd module-cmd10348183
Ref: 1910348183
Ref: library/cmd translation-repo10348183
Ref: 32f110348183
Ref: library/cmd cmd Cmd10348659
Ref: 17d510348659
Ref: cmd — Support for line-oriented command interpreters-Footnote-110350293
Node: Cmd Objects10350356
Ref: library/cmd cmd-objects10350478
Ref: 32f310350478
Ref: library/cmd id110350478
Ref: 32f410350478
Ref: library/cmd cmd Cmd cmdloop10350577
Ref: 32f510350577
Ref: library/cmd cmd Cmd do_help10352656
Ref: 17c410352656
Ref: library/cmd cmd Cmd onecmd10353189
Ref: 32f810353189
Ref: library/cmd cmd Cmd emptyline10353780
Ref: 32fb10353780
Ref: library/cmd cmd Cmd default10353978
Ref: 32fa10353978
Ref: library/cmd cmd Cmd completedefault10354175
Ref: 32fc10354175
Ref: library/cmd cmd Cmd columnize10354397
Ref: 19ad10354397
Ref: library/cmd cmd Cmd precmd10354633
Ref: 32f910354633
Ref: library/cmd cmd Cmd postcmd10355105
Ref: 32f710355105
Ref: library/cmd cmd Cmd preloop10355731
Ref: 32fd10355731
Ref: library/cmd cmd Cmd postloop10355925
Ref: 32fe10355925
Ref: library/cmd cmd Cmd prompt10356209
Ref: 32ff10356209
Ref: library/cmd cmd Cmd identchars10356278
Ref: 330010356278
Ref: library/cmd cmd Cmd lastcmd10356373
Ref: 330110356373
Ref: library/cmd cmd Cmd cmdqueue10356446
Ref: 330210356446
Ref: library/cmd cmd Cmd intro10356697
Ref: 32f610356697
Ref: library/cmd cmd Cmd doc_header10356851
Ref: 330310356851
Ref: library/cmd cmd Cmd misc_header10356971
Ref: 330410356971
Ref: library/cmd cmd Cmd undoc_header10357190
Ref: 330510357190
Ref: library/cmd cmd Cmd ruler10357406
Ref: 330610357406
Ref: library/cmd cmd Cmd use_rawinput10357580
Ref: 32f210357580
Node: Cmd Example10358056
Ref: library/cmd cmd-example10358178
Ref: 330710358178
Ref: library/cmd id210358178
Ref: 330810358178
Node: Concurrent Execution10363523
Ref: library/concurrency doc10363698
Ref: 330a10363698
Ref: library/concurrency concurrency10363698
Ref: 330b10363698
Ref: library/concurrency concurrent-execution10363698
Ref: 330c10363698
Ref: library/concurrency translation-repo10363698
Ref: 330d10363698
Node: threading — Thread-based parallelism10364651
Ref: library/threading doc10364800
Ref: 330e10364800
Ref: library/threading module-threading10364800
Ref: ed10364800
Ref: library/threading threading-thread-based-parallelism10364800
Ref: 330f10364800
Ref: threading — Thread-based parallelism-Footnote-110365547
Node: Introduction<8>10365616
Ref: library/threading introduction10365749
Ref: 331010365749
Ref: Introduction<8>-Footnote-110368631
Node: GIL and performance considerations10368688
Ref: library/threading gil-and-performance-considerations10368842
Ref: 331110368842
Ref: GIL and performance considerations-Footnote-110369647
Node: Reference<2>10369689
Ref: library/threading reference10369887
Ref: 331210369887
Ref: library/threading threading active_count10369972
Ref: 30a10369972
Ref: library/threading threading current_thread10370263
Ref: 30910370263
Ref: library/threading threading excepthook10370660
Ref: 85110370660
Ref: library/threading threading __excepthook__10371996
Ref: 85010371996
Ref: library/threading threading get_ident10372268
Ref: 119e10372268
Ref: library/threading threading get_native_id10372664
Ref: a4b10372664
Ref: library/threading threading enumerate10373218
Ref: 1a0010373218
Ref: library/threading threading main_thread10373602
Ref: 100d10373602
Ref: library/threading threading settrace10373829
Ref: 84e10373829
Ref: library/threading threading settrace_all_threads10374086
Ref: 4cb10374086
Ref: library/threading threading gettrace10374441
Ref: 84c10374441
Ref: library/threading threading setprofile10374569
Ref: 84f10374569
Ref: library/threading threading setprofile_all_threads10374832
Ref: 4cc10374832
Ref: library/threading threading getprofile10375193
Ref: 84d10375193
Ref: library/threading threading stack_size10375328
Ref: 331310375328
Ref: library/threading threading TIMEOUT_MAX10376654
Ref: 331410376654
Node: Thread-local data10377873
Ref: library/threading thread-local-data10377962
Ref: 331510377962
Ref: library/threading threading local10381069
Ref: 165010381069
Node: Thread objects10381146
Ref: library/threading id110381256
Ref: 331610381256
Ref: library/threading thread-objects10381256
Ref: 331710381256
Ref: library/threading threading Thread10383915
Ref: 95610383915
Ref: library/threading threading Thread start10385365
Ref: 2ea810385365
Ref: library/threading threading Thread run10385742
Ref: a4a10385742
Ref: library/threading meth-thread-join10386542
Ref: 331810386542
Ref: library/threading threading Thread join10386542
Ref: 122910386542
Ref: library/threading threading Thread name10387761
Ref: 30810387761
Ref: library/threading threading Thread getName10387979
Ref: 331910387979
Ref: library/threading threading Thread setName10388007
Ref: 30710388007
Ref: library/threading threading Thread ident10388189
Ref: 2e3310388189
Ref: library/threading threading Thread native_id10388581
Ref: a4c10388581
Ref: library/threading threading Thread is_alive10389394
Ref: 95710389394
Ref: library/threading threading Thread daemon10389725
Ref: 30610389725
Ref: library/threading threading Thread isDaemon10390313
Ref: 331a10390313
Ref: library/threading threading Thread setDaemon10390342
Ref: 30510390342
Node: Lock objects10390528
Ref: library/threading id210390634
Ref: 331b10390634
Ref: library/threading lock-objects10390634
Ref: 331c10390634
Ref: library/threading threading Lock10392020
Ref: 178a10392020
Ref: library/threading threading Lock acquire10392423
Ref: 69b10392423
Ref: library/threading threading Lock release10393760
Ref: 130a10393760
Ref: library/threading threading Lock locked10394245
Ref: 331e10394245
Node: RLock objects10394327
Ref: library/threading id310394436
Ref: 331f10394436
Ref: library/threading rlock-objects10394436
Ref: 332010394436
Ref: library/threading threading RLock10395785
Ref: 2de10395785
Ref: library/threading threading RLock acquire10396307
Ref: eaf10396307
Ref: library/threading threading RLock release10398287
Ref: 332110398287
Node: Condition objects10398984
Ref: library/threading condition-objects10399098
Ref: 332210399098
Ref: library/threading id410399098
Ref: 332310399098
Ref: library/threading threading Condition10402197
Ref: 119910402197
Ref: library/threading threading Condition acquire10402734
Ref: 332410402734
Ref: library/threading threading Condition release10402946
Ref: 332510402946
Ref: library/threading threading Condition wait10403129
Ref: 1a0c10403129
Ref: library/threading threading Condition wait_for10404653
Ref: 332610404653
Ref: library/threading threading Condition notify10405627
Ref: 190c10405627
Ref: library/threading threading Condition notify_all10406512
Ref: 30310406512
Node: Semaphore objects10406928
Ref: library/threading id510407046
Ref: 332710407046
Ref: library/threading semaphore-objects10407046
Ref: 332810407046
Ref: library/threading threading Semaphore10407732
Ref: 119a10407732
Ref: library/threading threading Semaphore acquire10408417
Ref: 129a10408417
Ref: library/threading threading Semaphore release10409691
Ref: 332910409691
Ref: library/threading threading BoundedSemaphore10410068
Ref: 119b10410068
Node: Semaphore example10410599
Ref: library/threading semaphore-example10410713
Ref: 332a10410713
Ref: library/threading semaphore-examples10410713
Ref: 332b10410713
Node: Event objects10411584
Ref: library/threading event-objects10411694
Ref: 332c10411694
Ref: library/threading id610411694
Ref: 332d10411694
Ref: library/threading threading Event10412098
Ref: 119c10412098
Ref: library/threading threading Event is_set10412494
Ref: 30410412494
Ref: library/threading threading Event set10412666
Ref: 332e10412666
Ref: library/threading threading Event clear10412894
Ref: 332f10412894
Ref: library/threading threading Event wait10413123
Ref: 137010413123
Node: Timer objects10413853
Ref: library/threading id710413961
Ref: 333010413961
Ref: library/threading timer-objects10413961
Ref: 333110413961
Ref: library/threading threading Timer10414725
Ref: 119d10414725
Ref: library/threading threading Timer cancel10415174
Ref: 333210415174
Node: Barrier objects10415364
Ref: library/threading barrier-objects10415450
Ref: 333310415450
Ref: library/threading threading Barrier10416400
Ref: 122810416400
Ref: library/threading threading Barrier wait10416744
Ref: 333410416744
Ref: library/threading threading Barrier reset10417892
Ref: 333510417892
Ref: library/threading threading Barrier abort10418329
Ref: 333610418329
Ref: library/threading threading Barrier parties10418819
Ref: 333710418819
Ref: library/threading threading Barrier n_waiting10418911
Ref: 333810418911
Ref: library/threading threading Barrier broken10419009
Ref: 333910419009
Ref: library/threading threading BrokenBarrierError10419126
Ref: 122a10419126
Node: Using locks conditions and semaphores in the with statement10419304
Ref: library/threading using-locks-conditions-and-semaphores-in-the-with-statement10419459
Ref: 333a10419459
Ref: library/threading with-locks10419459
Ref: 331d10419459
Node: multiprocessing — Process-based parallelism10420300
Ref: library/multiprocessing doc10420540
Ref: 333b10420540
Ref: library/multiprocessing module-multiprocessing10420540
Ref: 9410420540
Ref: library/multiprocessing multiprocessing-process-based-parallelism10420540
Ref: 333c10420540
Ref: library/multiprocessing translation-repo10420540
Ref: 333d10420540
Ref: multiprocessing — Process-based parallelism-Footnote-110421081
Node: Introduction<9>10421154
Ref: library/multiprocessing introduction10421272
Ref: 333e10421272
Node: The Process class10423309
Ref: library/multiprocessing the-process-class10423413
Ref: 334010423413
Node: Contexts and start methods10424878
Ref: library/multiprocessing contexts-and-start-methods10425027
Ref: 334210425027
Ref: library/multiprocessing multiprocessing-start-methods10425027
Ref: 2c810425027
Ref: library/multiprocessing multiprocessing-start-method-spawn10425217
Ref: 334310425217
Ref: library/multiprocessing multiprocessing-start-method-fork10425779
Ref: 334510425779
Ref: library/multiprocessing multiprocessing-start-method-forkserver10426848
Ref: 334610426848
Ref: Contexts and start methods-Footnote-110430646
Node: Exchanging objects between processes10430711
Ref: library/multiprocessing exchanging-objects-between-processes10430876
Ref: 334710430876
Node: Synchronization between processes10432763
Ref: library/multiprocessing synchronization-between-processes10432933
Ref: 334910432933
Node: Sharing state between processes10433648
Ref: library/multiprocessing sharing-state-between-processes10433805
Ref: 334a10433805
Node: Using a pool of workers10436898
Ref: library/multiprocessing using-a-pool-of-workers10437013
Ref: 335210437013
Node: Reference<3>10440303
Ref: library/multiprocessing reference10440452
Ref: 335310440452
Node: Global start method10440977
Ref: library/multiprocessing global-start-method10441076
Ref: 335410441076
Ref: library/multiprocessing id110441076
Ref: 335510441076
Node: Process and exceptions10441695
Ref: library/multiprocessing process-and-exceptions10441819
Ref: 335610441819
Ref: library/multiprocessing multiprocessing Process10441894
Ref: b7510441894
Ref: library/multiprocessing multiprocessing Process run10445024
Ref: 334410445024
Ref: library/multiprocessing multiprocessing Process start10445820
Ref: 13de10445820
Ref: library/multiprocessing multiprocessing Process join10446069
Ref: 13e010446069
Ref: library/multiprocessing multiprocessing Process name10446784
Ref: 335710446784
Ref: library/multiprocessing multiprocessing Process is_alive10447249
Ref: 13df10447249
Ref: library/multiprocessing multiprocessing Process daemon10447485
Ref: 335810447485
Ref: library/multiprocessing multiprocessing Process pid10448360
Ref: 335b10448360
Ref: library/multiprocessing multiprocessing Process exitcode10448485
Ref: 335a10448485
Ref: library/multiprocessing multiprocessing Process authkey10449087
Ref: 335c10449087
Ref: library/multiprocessing multiprocessing Process sentinel10449594
Ref: 112510449594
Ref: library/multiprocessing multiprocessing Process terminate10450235
Ref: 333f10450235
Ref: library/multiprocessing multiprocessing Process kill10451046
Ref: b7310451046
Ref: library/multiprocessing multiprocessing Process close10451204
Ref: b7210451204
Ref: library/multiprocessing multiprocessing ProcessError10452470
Ref: 335e10452470
Ref: library/multiprocessing multiprocessing BufferTooShort10452577
Ref: 335f10452577
Ref: library/multiprocessing multiprocessing AuthenticationError10452879
Ref: 336010452879
Ref: library/multiprocessing multiprocessing TimeoutError10452983
Ref: 336110452983
Ref: Process and exceptions-Footnote-110453129
Node: Pipes and Queues10453185
Ref: library/multiprocessing pipes-and-queues10453306
Ref: 336210453306
Ref: library/multiprocessing multiprocessing Pipe10456986
Ref: 334810456986
Ref: library/multiprocessing multiprocessing Queue10457533
Ref: 192f10457533
Ref: library/multiprocessing multiprocessing Queue qsize10458250
Ref: 336d10458250
Ref: library/multiprocessing multiprocessing Queue empty10458592
Ref: 170410458592
Ref: library/multiprocessing multiprocessing Queue full10458879
Ref: 336e10458879
Ref: library/multiprocessing multiprocessing Queue put10459074
Ref: 1bcc10459074
Ref: library/multiprocessing multiprocessing Queue put_nowait10459894
Ref: 336f10459894
Ref: library/multiprocessing multiprocessing Queue get10459977
Ref: 1bcd10459977
Ref: library/multiprocessing multiprocessing Queue get_nowait10460758
Ref: 336a10460758
Ref: library/multiprocessing multiprocessing Queue close10461005
Ref: 193010461005
Ref: library/multiprocessing multiprocessing Queue join_thread10461464
Ref: 337010461464
Ref: library/multiprocessing multiprocessing Queue cancel_join_thread10462008
Ref: 336b10462008
Ref: library/multiprocessing multiprocessing SimpleQueue10463142
Ref: 91d10463142
Ref: library/multiprocessing multiprocessing SimpleQueue close10463403
Ref: 91e10463403
Ref: library/multiprocessing multiprocessing SimpleQueue empty10463714
Ref: 170510463714
Ref: library/multiprocessing multiprocessing SimpleQueue get10463904
Ref: 337110463904
Ref: library/multiprocessing multiprocessing SimpleQueue put10463982
Ref: 337210463982
Ref: library/multiprocessing multiprocessing JoinableQueue10464049
Ref: 336310464049
Ref: library/multiprocessing multiprocessing JoinableQueue task_done10464388
Ref: 336610464388
Ref: library/multiprocessing multiprocessing JoinableQueue join10465062
Ref: 337310465062
Ref: Pipes and Queues-Footnote-110465566
Node: Miscellaneous<3>10465630
Ref: library/multiprocessing miscellaneous10465747
Ref: 337410465747
Ref: library/multiprocessing multiprocessing active_children10465796
Ref: 337510465796
Ref: library/multiprocessing multiprocessing cpu_count10466013
Ref: fa810466013
Ref: library/multiprocessing multiprocessing current_process10466755
Ref: 337610466755
Ref: library/multiprocessing multiprocessing parent_process10466952
Ref: 337710466952
Ref: library/multiprocessing multiprocessing freeze_support10467221
Ref: 15b210467221
Ref: library/multiprocessing multiprocessing get_all_start_methods10468210
Ref: fa210468210
Ref: library/multiprocessing multiprocessing get_context10468565
Ref: 2c610468565
Ref: library/multiprocessing multiprocessing get_start_method10469207
Ref: fa310469207
Ref: library/multiprocessing multiprocessing set_executable10469939
Ref: 193610469939
Ref: library/multiprocessing multiprocessing set_forkserver_preload10470482
Ref: 16a010470482
Ref: library/multiprocessing multiprocessing set_start_method10471193
Ref: 2c710471193
Ref: Miscellaneous<3>-Footnote-110472292
Node: Connection Objects10472357
Ref: library/multiprocessing connection-objects10472484
Ref: 337810472484
Ref: library/multiprocessing multiprocessing connection Connection10472803
Ref: 112410472803
Ref: library/multiprocessing multiprocessing connection Connection send10472853
Ref: 337a10472853
Ref: library/multiprocessing multiprocessing connection Connection recv10473180
Ref: 337b10473180
Ref: library/multiprocessing multiprocessing connection Connection fileno10473473
Ref: 337c10473473
Ref: library/multiprocessing multiprocessing connection Connection close10473573
Ref: 337d10473573
Ref: library/multiprocessing multiprocessing connection Connection poll10473725
Ref: 337e10473725
Ref: library/multiprocessing multiprocessing connection Connection send_bytes10474212
Ref: 337f10474212
Ref: library/multiprocessing multiprocessing connection Connection recv_bytes10474671
Ref: 338010474671
Ref: library/multiprocessing multiprocessing connection Connection recv_bytes_into10475313
Ref: 338110475313
Ref: library/multiprocessing multiprocessing-recv-pickle-security10477127
Ref: 338210477127
Node: Synchronization primitives10477813
Ref: library/multiprocessing synchronization-primitives10477945
Ref: 338310477945
Ref: library/multiprocessing multiprocessing Barrier10478315
Ref: 335110478315
Ref: library/multiprocessing multiprocessing BoundedSemaphore10478601
Ref: 334f10478601
Ref: library/multiprocessing multiprocessing Condition10479225
Ref: 335010479225
Ref: library/multiprocessing multiprocessing Event10479681
Ref: 19aa10479681
Ref: library/multiprocessing multiprocessing Lock10479886
Ref: 16a210479886
Ref: library/multiprocessing multiprocessing Lock acquire10480828
Ref: 338410480828
Ref: library/multiprocessing multiprocessing Lock release10482354
Ref: 338510482354
Ref: library/multiprocessing multiprocessing RLock10482723
Ref: 15c110482723
Ref: library/multiprocessing multiprocessing RLock acquire10483565
Ref: 338610483565
Ref: library/multiprocessing multiprocessing RLock release10485214
Ref: 338710485214
Ref: library/multiprocessing multiprocessing Semaphore10486191
Ref: 334e10486191
Ref: Synchronization primitives-Footnote-110487180
Node: Shared ctypes Objects10487244
Ref: library/multiprocessing shared-ctypes-objects10487366
Ref: 338810487366
Ref: library/multiprocessing multiprocessing Value10487543
Ref: 334b10487543
Ref: library/multiprocessing multiprocessing Array10488972
Ref: 334c10488972
Node: The multiprocessing sharedctypes module10490574
Ref: library/multiprocessing module-multiprocessing sharedctypes10490671
Ref: 9a10490671
Ref: library/multiprocessing the-multiprocessing-sharedctypes-module10490671
Ref: 338910490671
Ref: library/multiprocessing multiprocessing sharedctypes RawArray10491297
Ref: 338a10491297
Ref: library/multiprocessing multiprocessing sharedctypes RawValue10492126
Ref: 338c10492126
Ref: library/multiprocessing multiprocessing sharedctypes Array10492910
Ref: 338b10492910
Ref: library/multiprocessing multiprocessing sharedctypes Value10493900
Ref: 338d10493900
Ref: library/multiprocessing multiprocessing sharedctypes copy10494874
Ref: 338e10494874
Ref: library/multiprocessing multiprocessing sharedctypes synchronized10495036
Ref: e6410495036
Node: Managers10498276
Ref: library/multiprocessing managers10498385
Ref: 338f10498385
Ref: library/multiprocessing multiprocessing-managers10498385
Ref: 336710498385
Ref: library/multiprocessing multiprocessing Manager10498735
Ref: ce010498735
Ref: library/multiprocessing module-multiprocessing managers10499056
Ref: 9710499056
Ref: library/multiprocessing multiprocessing managers BaseManager10499245
Ref: 339110499245
Ref: library/multiprocessing multiprocessing managers BaseManager start10500768
Ref: 339210500768
Ref: library/multiprocessing multiprocessing managers BaseManager get_server10501003
Ref: 339410501003
Ref: library/multiprocessing multiprocessing managers BaseManager connect10501547
Ref: 339610501547
Ref: library/multiprocessing multiprocessing managers BaseManager shutdown10501828
Ref: 339310501828
Ref: library/multiprocessing multiprocessing managers BaseManager register10502064
Ref: 339710502064
Ref: library/multiprocessing multiprocessing managers BaseManager address10504367
Ref: 339510504367
Ref: library/multiprocessing multiprocessing managers SyncManager10504898
Ref: 339010504898
Ref: library/multiprocessing multiprocessing managers SyncManager Barrier10505338
Ref: 339a10505338
Ref: library/multiprocessing multiprocessing managers SyncManager BoundedSemaphore10505530
Ref: 339b10505530
Ref: library/multiprocessing multiprocessing managers SyncManager Condition10505686
Ref: 339c10505686
Ref: library/multiprocessing multiprocessing managers SyncManager Event10506060
Ref: 339d10506060
Ref: library/multiprocessing multiprocessing managers SyncManager Lock10506187
Ref: 13e410506187
Ref: library/multiprocessing multiprocessing managers SyncManager Namespace10506312
Ref: 339e10506312
Ref: library/multiprocessing multiprocessing managers SyncManager Queue10506437
Ref: 2ec210506437
Ref: library/multiprocessing multiprocessing managers SyncManager RLock10506569
Ref: 13e510506569
Ref: library/multiprocessing multiprocessing managers SyncManager Semaphore10506695
Ref: 13e610506695
Ref: library/multiprocessing multiprocessing managers SyncManager Array10506837
Ref: 339f10506837
Ref: library/multiprocessing multiprocessing managers SyncManager Value10506936
Ref: 33a010506936
Ref: library/multiprocessing multiprocessing managers SyncManager dict10507081
Ref: 33a110507081
Ref: library/multiprocessing multiprocessing managers SyncManager list10507262
Ref: 33a210507262
Ref: library/multiprocessing multiprocessing managers Namespace10507662
Ref: 334d10507662
Node: Customized managers10508502
Ref: library/multiprocessing customized-managers10508597
Ref: 33a310508597
Node: Using a remote manager10509369
Ref: library/multiprocessing using-a-remote-manager10509464
Ref: 33a410509464
Node: Proxy Objects10511605
Ref: library/multiprocessing multiprocessing-proxy-objects10511706
Ref: cdf10511706
Ref: library/multiprocessing proxy-objects10511706
Ref: 33a510511706
Ref: library/multiprocessing multiprocessing managers BaseProxy10514985
Ref: 339810514985
Ref: library/multiprocessing multiprocessing managers BaseProxy _callmethod10515100
Ref: 339910515100
Ref: library/multiprocessing multiprocessing managers BaseProxy _getvalue10516652
Ref: 33a610516652
Ref: library/multiprocessing multiprocessing managers BaseProxy __repr__10516812
Ref: 33a710516812
Ref: library/multiprocessing multiprocessing managers BaseProxy __str__10516898
Ref: 33a810516898
Node: Cleanup<2>10517014
Ref: library/multiprocessing cleanup10517074
Ref: 33a910517074
Node: Process Pools10517363
Ref: library/multiprocessing module-multiprocessing pool10517477
Ref: 9810517477
Ref: library/multiprocessing process-pools10517477
Ref: 33aa10517477
Ref: library/multiprocessing multiprocessing pool Pool10517638
Ref: fa410517638
Ref: library/multiprocessing multiprocessing pool Pool apply10520616
Ref: 13e210520616
Ref: library/multiprocessing multiprocessing pool Pool apply_async10520987
Ref: 13e310520987
Ref: library/multiprocessing multiprocessing pool Pool map10521839
Ref: 112910521839
Ref: library/multiprocessing multiprocessing pool Pool map_async10522624
Ref: 112a10522624
Ref: library/multiprocessing multiprocessing pool Pool imap10523479
Ref: 33ae10523479
Ref: library/multiprocessing multiprocessing pool Pool imap_unordered10524184
Ref: 33af10524184
Ref: library/multiprocessing multiprocessing pool Pool starmap10524510
Ref: 112610524510
Ref: library/multiprocessing multiprocessing pool Pool starmap_async10524865
Ref: 112710524865
Ref: library/multiprocessing multiprocessing pool Pool close10525220
Ref: 33ab10525220
Ref: library/multiprocessing multiprocessing pool Pool terminate10525407
Ref: 33ac10525407
Ref: library/multiprocessing multiprocessing pool Pool join10525634
Ref: 33b010525634
Ref: library/multiprocessing multiprocessing pool AsyncResult10526076
Ref: 33ad10526076
Ref: library/multiprocessing multiprocessing pool AsyncResult get10526234
Ref: 33b110526234
Ref: library/multiprocessing multiprocessing pool AsyncResult wait10526593
Ref: 33b210526593
Ref: library/multiprocessing multiprocessing pool AsyncResult ready10526717
Ref: 33b310526717
Ref: library/multiprocessing multiprocessing pool AsyncResult successful10526794
Ref: 33b410526794
Node: Listeners and Clients10528087
Ref: library/multiprocessing listeners-and-clients10528207
Ref: 33b510528207
Ref: library/multiprocessing module-multiprocessing connection10528207
Ref: 9510528207
Ref: library/multiprocessing multiprocessing-listeners-clients10528207
Ref: 337910528207
Ref: library/multiprocessing multiprocessing connection deliver_challenge10528738
Ref: 33b610528738
Ref: library/multiprocessing multiprocessing connection answer_challenge10529144
Ref: 33b710529144
Ref: library/multiprocessing multiprocessing connection Client10529458
Ref: 33b810529458
Ref: library/multiprocessing multiprocessing connection Listener10530222
Ref: 17bb10530222
Ref: library/multiprocessing multiprocessing connection Listener accept10531992
Ref: 177310531992
Ref: library/multiprocessing multiprocessing connection Listener close10532274
Ref: 33ba10532274
Ref: library/multiprocessing multiprocessing connection Listener address10532574
Ref: 33bb10532574
Ref: library/multiprocessing multiprocessing connection Listener last_accepted10532670
Ref: 33bc10532670
Ref: library/multiprocessing multiprocessing connection wait10533090
Ref: 112310533090
Node: Address Formats10537112
Ref: library/multiprocessing address-formats10537185
Ref: 33bd10537185
Ref: library/multiprocessing multiprocessing-address-formats10537185
Ref: 33b910537185
Node: Authentication keys10537899
Ref: library/multiprocessing authentication-keys10538016
Ref: 33be10538016
Ref: library/multiprocessing multiprocessing-auth-keys10538016
Ref: 335d10538016
Node: Logging<2>10539194
Ref: library/multiprocessing logging10539322
Ref: 33bf10539322
Ref: library/multiprocessing multiprocessing get_logger10539590
Ref: 2f1d10539590
Ref: library/multiprocessing multiprocessing log_to_stderr10540105
Ref: 33c010540105
Node: The multiprocessing dummy module10541212
Ref: library/multiprocessing module-multiprocessing dummy10541312
Ref: 9610541312
Ref: library/multiprocessing the-multiprocessing-dummy-module10541312
Ref: 33c110541312
Ref: library/multiprocessing multiprocessing pool ThreadPool10541821
Ref: 1a7a10541821
Node: Programming guidelines10543565
Ref: library/multiprocessing multiprocessing-programming10543711
Ref: 334110543711
Ref: library/multiprocessing programming-guidelines10543711
Ref: 33c210543711
Node: All start methods10543955
Ref: library/multiprocessing all-start-methods10544078
Ref: 33c310544078
Ref: library/multiprocessing multiprocessing-programming-spawn10550129
Ref: 335910550129
Ref: All start methods-Footnote-110550166
Ref: All start methods-Footnote-210550230
Ref: All start methods-Footnote-310550294
Node: The spawn and forkserver start methods10550358
Ref: library/multiprocessing multiprocessing-programming-forkserver10550481
Ref: 33c410550481
Ref: library/multiprocessing the-spawn-and-forkserver-start-methods10550481
Ref: 33c510550481
Ref: library/multiprocessing multiprocessing-safe-main-import10551287
Ref: 33c610551287
Node: Examples<14>10552562
Ref: library/multiprocessing examples10552687
Ref: 33c710552687
Ref: library/multiprocessing multiprocessing-examples10552687
Ref: 336c10552687
Node: multiprocessing shared_memory — Shared memory for direct access across processes10561598
Ref: library/multiprocessing shared_memory doc10561822
Ref: 33c810561822
Ref: library/multiprocessing shared_memory module-multiprocessing shared_memory10561822
Ref: 9910561822
Ref: library/multiprocessing shared_memory multiprocessing-shared-memory-shared-memory-for-direct-access-across-processes10561822
Ref: 33c910561822
Ref: library/multiprocessing shared_memory translation-repo10561822
Ref: 33ca10561822
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory10563380
Ref: 176c10563380
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory close10566688
Ref: 33cc10566688
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory unlink10567156
Ref: 33cd10567156
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory buf10567762
Ref: 33ce10567762
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory name10567851
Ref: 33cf10567851
Ref: library/multiprocessing shared_memory multiprocessing shared_memory SharedMemory size10567962
Ref: 33d010567962
Ref: library/multiprocessing shared_memory multiprocessing managers SharedMemoryManager10571052
Ref: 33cb10571052
Ref: library/multiprocessing shared_memory multiprocessing managers SharedMemoryManager SharedMemory10572454
Ref: 33d110572454
Ref: library/multiprocessing shared_memory multiprocessing managers SharedMemoryManager ShareableList10572606
Ref: 33d210572606
Ref: library/multiprocessing shared_memory multiprocessing shared_memory ShareableList10574463
Ref: 1b0110574463
Ref: library/multiprocessing shared_memory multiprocessing shared_memory ShareableList count10576959
Ref: 33d310576959
Ref: library/multiprocessing shared_memory multiprocessing shared_memory ShareableList index10577047
Ref: 33d410577047
Ref: library/multiprocessing shared_memory multiprocessing shared_memory ShareableList format10577197
Ref: 33d510577197
Ref: library/multiprocessing shared_memory multiprocessing shared_memory ShareableList shm10577351
Ref: 33d610577351
Ref: multiprocessing shared_memory — Shared memory for direct access across processes-Footnote-110579943
Ref: multiprocessing shared_memory — Shared memory for direct access across processes-Footnote-210580033
Ref: multiprocessing shared_memory — Shared memory for direct access across processes-Footnote-310580060
Node: The concurrent package10580116
Ref: library/concurrent doc10580342
Ref: 33d710580342
Ref: library/concurrent the-concurrent-package10580342
Ref: 33d810580342
Ref: library/concurrent translation-repo10580342
Ref: 33d910580342
Node: concurrent futures — Launching parallel tasks10580530
Ref: library/concurrent futures doc10580710
Ref: 33da10580710
Ref: library/concurrent futures concurrent-futures-launching-parallel-tasks10580710
Ref: 33db10580710
Ref: library/concurrent futures module-concurrent futures10580710
Ref: 2110580710
Ref: library/concurrent futures translation-repo10580710
Ref: 33dc10580710
Ref: concurrent futures — Launching parallel tasks-Footnote-110581971
Ref: concurrent futures — Launching parallel tasks-Footnote-210582057
Node: Executor Objects10582144
Ref: library/concurrent futures executor-objects10582271
Ref: 33df10582271
Ref: library/concurrent futures concurrent futures Executor10582324
Ref: 33dd10582324
Ref: library/concurrent futures concurrent futures Executor submit10582523
Ref: a9110582523
Ref: library/concurrent futures concurrent futures Executor map10582933
Ref: e1410582933
Ref: library/concurrent futures concurrent futures Executor shutdown10584381
Ref: 8f610584381
Node: ThreadPoolExecutor10586531
Ref: library/concurrent futures threadpoolexecutor10586686
Ref: 33e010586686
Ref: library/concurrent futures concurrent futures ThreadPoolExecutor10587905
Ref: 74510587905
Node: ThreadPoolExecutor Example10590269
Ref: library/concurrent futures id110590350
Ref: 33e210590350
Ref: library/concurrent futures threadpoolexecutor-example10590350
Ref: 11f710590350
Node: ProcessPoolExecutor10591558
Ref: library/concurrent futures processpoolexecutor10591711
Ref: 33e310591711
Ref: library/concurrent futures concurrent futures ProcessPoolExecutor10592730
Ref: 8f710592730
Ref: ProcessPoolExecutor-Footnote-110596578
Node: ProcessPoolExecutor Example10596634
Ref: library/concurrent futures id210596717
Ref: 33e510596717
Ref: library/concurrent futures processpoolexecutor-example10596717
Ref: 11f810596717
Node: Future Objects10597623
Ref: library/concurrent futures future-objects10597774
Ref: 33e610597774
Ref: library/concurrent futures concurrent futures Future10597978
Ref: 11f610597978
Ref: library/concurrent futures concurrent futures Future cancel10598211
Ref: 33e710598211
Ref: library/concurrent futures concurrent futures Future cancelled10598510
Ref: 33e810598510
Ref: library/concurrent futures concurrent futures Future running10598610
Ref: 33e910598610
Ref: library/concurrent futures concurrent futures Future done10598743
Ref: 33ea10598743
Ref: library/concurrent futures concurrent futures Future result10598868
Ref: 33eb10598868
Ref: library/concurrent futures concurrent futures Future exception10599525
Ref: 33ec10599525
Ref: library/concurrent futures concurrent futures Future add_done_callback10600165
Ref: 33ed10600165
Ref: library/concurrent futures concurrent futures Future set_running_or_notify_cancel10600996
Ref: 33ee10600996
Ref: library/concurrent futures concurrent futures Future set_result10601955
Ref: 33ef10601955
Ref: library/concurrent futures concurrent futures Future set_exception10602359
Ref: 33f010602359
Node: Module Functions10602798
Ref: library/concurrent futures module-functions10602947
Ref: 33f110602947
Ref: library/concurrent futures concurrent futures wait10603000
Ref: 19a910603000
Ref: library/concurrent futures concurrent futures FIRST_COMPLETED10604321
Ref: 33f210604321
Ref: library/concurrent futures concurrent futures FIRST_EXCEPTION10604630
Ref: 33f310604630
Ref: library/concurrent futures concurrent futures ALL_COMPLETED10605151
Ref: 33f410605151
Ref: library/concurrent futures concurrent futures as_completed10605353
Ref: 175b10605353
Ref: Module Functions-Footnote-110606374
Node: Exception classes10606416
Ref: library/concurrent futures exception-classes10606542
Ref: 33f510606542
Ref: library/concurrent futures concurrent futures CancelledError10606597
Ref: 9e610606597
Ref: library/concurrent futures concurrent futures TimeoutError10606688
Ref: 33f610606688
Ref: library/concurrent futures concurrent futures BrokenExecutor10606935
Ref: 33f710606935
Ref: library/concurrent futures concurrent futures InvalidStateError10607193
Ref: 171510607193
Ref: library/concurrent futures concurrent futures thread BrokenThreadPool10607377
Ref: 33e110607377
Ref: library/concurrent futures concurrent futures process BrokenProcessPool10607637
Ref: 33e410607637
Node: subprocess — Subprocess management10608005
Ref: library/subprocess doc10608188
Ref: 33f810608188
Ref: library/subprocess module-subprocess10608188
Ref: d610608188
Ref: library/subprocess subprocess-subprocess-management10608188
Ref: 33f910608188
Ref: library/subprocess translation-repo10608188
Ref: 33fa10608188
Ref: subprocess — Subprocess management-Footnote-110609289
Ref: subprocess — Subprocess management-Footnote-210609359
Node: Using the subprocess Module10609401
Ref: library/subprocess using-the-subprocess-module10609533
Ref: 33fb10609533
Ref: library/subprocess subprocess run10609836
Ref: ba410609836
Ref: library/subprocess subprocess CompletedProcess10614406
Ref: ea710614406
Ref: library/subprocess subprocess CompletedProcess args10614539
Ref: 33fe10614539
Ref: library/subprocess subprocess CompletedProcess returncode10614661
Ref: 33ff10614661
Ref: library/subprocess subprocess CompletedProcess stdout10614935
Ref: 340010614935
Ref: library/subprocess subprocess CompletedProcess stderr10615366
Ref: 340110615366
Ref: library/subprocess subprocess CompletedProcess check_returncode10615608
Ref: 340210615608
Ref: library/subprocess subprocess DEVNULL10615775
Ref: 119210615775
Ref: library/subprocess subprocess PIPE10616021
Ref: ba510616021
Ref: library/subprocess subprocess STDOUT10616285
Ref: 33fd10616285
Ref: library/subprocess subprocess SubprocessError10616492
Ref: 340310616492
Ref: library/subprocess subprocess TimeoutExpired10616623
Ref: 15f310616623
Ref: library/subprocess subprocess TimeoutExpired cmd10616782
Ref: 340410616782
Ref: library/subprocess subprocess TimeoutExpired timeout10616868
Ref: 340510616868
Ref: library/subprocess subprocess TimeoutExpired output10616928
Ref: 340610616928
Ref: library/subprocess subprocess TimeoutExpired stdout10617311
Ref: 340710617311
Ref: library/subprocess subprocess TimeoutExpired stderr10617406
Ref: 340810617406
Ref: library/subprocess subprocess CalledProcessError10617873
Ref: 136e10617873
Ref: library/subprocess subprocess CalledProcessError returncode10618135
Ref: 340a10618135
Ref: library/subprocess subprocess CalledProcessError cmd10618303
Ref: 340b10618303
Ref: library/subprocess subprocess CalledProcessError output10618389
Ref: 340c10618389
Ref: library/subprocess subprocess CalledProcessError stdout10618560
Ref: 340d10618560
Ref: library/subprocess subprocess CalledProcessError stderr10618655
Ref: 340e10618655
Node: Frequently Used Arguments10618964
Ref: library/subprocess frequently-used-arguments10619079
Ref: 33fc10619079
Ref: library/subprocess id110619079
Ref: 340f10619079
Node: Popen Constructor10623236
Ref: library/subprocess popen-constructor10623374
Ref: 341410623374
Ref: library/subprocess subprocess Popen10623669
Ref: 19910623669
Ref: Popen Constructor-Footnote-110641524
Node: Exceptions<11>10641584
Ref: library/subprocess exceptions10641688
Ref: 342510641688
Node: Security Considerations10642934
Ref: library/subprocess security-considerations10643088
Ref: 341310643088
Ref: library/subprocess subprocess-security10643088
Ref: 342610643088
Ref: Security Considerations-Footnote-110644204
Ref: Security Considerations-Footnote-210644274
Node: Popen Objects10644330
Ref: library/subprocess popen-objects10644478
Ref: 342810644478
Ref: library/subprocess subprocess Popen poll10644595
Ref: 342910644595
Ref: library/subprocess subprocess Popen wait10644754
Ref: d0b10644754
Ref: library/subprocess subprocess Popen communicate10645760
Ref: 15f210645760
Ref: library/subprocess subprocess Popen send_signal10647892
Ref: 142c10647892
Ref: library/subprocess subprocess Popen terminate10648277
Ref: 142a10648277
Ref: library/subprocess subprocess Popen kill10648496
Ref: 142b10648496
Ref: library/subprocess subprocess Popen args10648795
Ref: 342a10648795
Ref: library/subprocess subprocess Popen stdin10648980
Ref: 341010648980
Ref: library/subprocess subprocess Popen stdout10649416
Ref: 341110649416
Ref: library/subprocess subprocess Popen stderr10649924
Ref: 341210649924
Ref: library/subprocess subprocess Popen pid10650694
Ref: 342b10650694
Ref: library/subprocess subprocess Popen returncode10650876
Ref: aa110650876
Node: Windows Popen Helpers10651651
Ref: library/subprocess windows-popen-helpers10651796
Ref: 342c10651796
Ref: library/subprocess subprocess STARTUPINFO10651950
Ref: 341810651950
Ref: library/subprocess subprocess STARTUPINFO dwFlags10652369
Ref: 342d10652369
Ref: library/subprocess subprocess STARTUPINFO hStdInput10652676
Ref: 342e10652676
Ref: library/subprocess subprocess STARTUPINFO hStdOutput10652981
Ref: 343010652981
Ref: library/subprocess subprocess STARTUPINFO hStdError10653292
Ref: 343110653292
Ref: library/subprocess subprocess STARTUPINFO wShowWindow10653600
Ref: 343210653600
Ref: library/subprocess subprocess STARTUPINFO lpAttributeList10654092
Ref: c2e10654092
Ref: Windows Popen Helpers-Footnote-110655348
Ref: Windows Popen Helpers-Footnote-210655420
Ref: Windows Popen Helpers-Footnote-310655492
Node: Windows Constants10655581
Ref: library/subprocess windows-constants10655656
Ref: 343510655656
Ref: library/subprocess subprocess STD_INPUT_HANDLE10655773
Ref: 343610655773
Ref: library/subprocess subprocess STD_OUTPUT_HANDLE10655910
Ref: 343710655910
Ref: library/subprocess subprocess STD_ERROR_HANDLE10656058
Ref: 343810656058
Ref: library/subprocess subprocess SW_HIDE10656204
Ref: 343410656204
Ref: library/subprocess subprocess STARTF_USESTDHANDLES10656293
Ref: 342f10656293
Ref: library/subprocess subprocess STARTF_USESHOWWINDOW10656524
Ref: 343310656524
Ref: library/subprocess subprocess STARTF_FORCEONFEEDBACK10656677
Ref: 343910656677
Ref: library/subprocess subprocess STARTF_FORCEOFFFEEDBACK10656971
Ref: 343a10656971
Ref: library/subprocess subprocess CREATE_NEW_CONSOLE10657181
Ref: 341910657181
Ref: library/subprocess subprocess CREATE_NEW_PROCESS_GROUP10657328
Ref: 341a10657328
Ref: library/subprocess subprocess ABOVE_NORMAL_PRIORITY_CLASS10657651
Ref: 341b10657651
Ref: library/subprocess subprocess BELOW_NORMAL_PRIORITY_CLASS10657857
Ref: 341c10657857
Ref: library/subprocess subprocess HIGH_PRIORITY_CLASS10658062
Ref: 341d10658062
Ref: library/subprocess subprocess IDLE_PRIORITY_CLASS10658250
Ref: 341e10658250
Ref: library/subprocess subprocess NORMAL_PRIORITY_CLASS10658448
Ref: 341f10658448
Ref: library/subprocess subprocess REALTIME_PRIORITY_CLASS10658651
Ref: 342010658651
Ref: library/subprocess subprocess CREATE_NO_WINDOW10659187
Ref: 342110659187
Ref: library/subprocess subprocess DETACHED_PROCESS10659371
Ref: 342210659371
Ref: library/subprocess subprocess CREATE_DEFAULT_ERROR_MODE10659627
Ref: 342310659627
Ref: library/subprocess subprocess CREATE_BREAKAWAY_FROM_JOB10660029
Ref: 342410660029
Node: Older high-level API10660228
Ref: library/subprocess call-function-trio10660412
Ref: 343b10660412
Ref: library/subprocess older-high-level-api10660412
Ref: 343c10660412
Ref: library/subprocess subprocess call10660660
Ref: ba610660660
Ref: library/subprocess subprocess check_call10662047
Ref: 340910662047
Ref: library/subprocess subprocess check_output10663701
Ref: ffb10663701
Node: Replacing Older Functions with the subprocess Module10666253
Ref: library/subprocess replacing-older-functions-with-the-subprocess-module10666449
Ref: 343d10666449
Ref: library/subprocess subprocess-replacements10666449
Ref: 11cc10666449
Node: Replacing /bin/sh shell command substitution10667612
Ref: library/subprocess replacing-bin-sh-shell-command-substitution10667778
Ref: 343e10667778
Node: Replacing shell pipeline10667983
Ref: library/subprocess replacing-shell-pipeline10668177
Ref: 343f10668177
Node: Replacing os system10668828
Ref: library/subprocess replacing-os-system10669007
Ref: 344010669007
Node: Replacing the os spawn family10669950
Ref: library/subprocess replacing-the-os-spawn-family10670143
Ref: 344110670143
Node: Replacing os popen os popen2 os popen310670774
Ref: library/subprocess replacing-os-popen-os-popen2-os-popen310670990
Ref: 344210670990
Node: Replacing functions from the popen2 module10672285
Ref: library/subprocess replacing-functions-from-the-popen2-module10672463
Ref: 344310672463
Node: Legacy Shell Invocation Functions10673777
Ref: library/subprocess legacy-shell-invocation-functions10673961
Ref: 344410673961
Ref: library/subprocess subprocess getstatusoutput10674325
Ref: ffd10674325
Ref: library/subprocess subprocess getoutput10675646
Ref: ffc10675646
Node: Notes<2>10676204
Ref: library/subprocess notes10676327
Ref: 344510676327
Node: Timeout Behavior10676534
Ref: library/subprocess subprocess-timeout-behavior10676658
Ref: 344610676658
Ref: library/subprocess timeout-behavior10676658
Ref: 344710676658
Node: Converting an argument sequence to a string on Windows10677445
Ref: library/subprocess converting-an-argument-sequence-to-a-string-on-windows10677615
Ref: 344810677615
Ref: library/subprocess converting-argument-sequence10677615
Ref: 341510677615
Ref: library/subprocess disable-vfork10678775
Ref: 344910678775
Node: Disabling use of vfork or posix_spawn10678775
Ref: library/subprocess disable-posix-spawn10678920
Ref: 344a10678920
Ref: library/subprocess disabling-use-of-vfork-or-posix-spawn10678920
Ref: 344b10678920
Node: sched — Event scheduler10680330
Ref: library/sched doc10680502
Ref: 344c10680502
Ref: library/sched module-sched10680502
Ref: bf10680502
Ref: library/sched sched-event-scheduler10680502
Ref: 344d10680502
Ref: library/sched translation-repo10680502
Ref: 344e10680502
Ref: library/sched sched scheduler10680767
Ref: 116b10680767
Ref: sched — Event scheduler-Footnote-110682824
Node: Scheduler Objects10682889
Ref: library/sched id110682968
Ref: 344f10682968
Ref: library/sched scheduler-objects10682968
Ref: 345010682968
Ref: library/sched sched scheduler enterabs10683100
Ref: 116d10683100
Ref: library/sched sched scheduler enter10683984
Ref: 116c10683984
Ref: library/sched sched scheduler cancel10684394
Ref: 1aa210684394
Ref: library/sched sched scheduler empty10684581
Ref: 345110684581
Ref: library/sched sched scheduler run10684666
Ref: 116a10684666
Ref: library/sched sched scheduler queue10685702
Ref: 345210685702
Node: queue — A synchronized queue class10685961
Ref: library/queue doc10686130
Ref: 345310686130
Ref: library/queue module-queue10686130
Ref: b610686130
Ref: library/queue queue-a-synchronized-queue-class10686130
Ref: 345410686130
Ref: library/queue translation-repo10686130
Ref: 345510686130
Ref: library/queue queue Queue10687444
Ref: 13e110687444
Ref: library/queue queue LifoQueue10687808
Ref: 240e10687808
Ref: library/queue queue PriorityQueue10688176
Ref: 240f10688176
Ref: library/queue queue SimpleQueue10689173
Ref: b8610689173
Ref: library/queue queue Empty10689349
Ref: 336810689349
Ref: library/queue queue Full10689535
Ref: 336910689535
Ref: library/queue queue ShutDown10689719
Ref: 23b10689719
Ref: queue — A synchronized queue class-Footnote-110690008
Node: Queue Objects10690073
Ref: library/queue queue-objects10690187
Ref: 345810690187
Ref: library/queue queueobjects10690187
Ref: 345910690187
Ref: library/queue queue Queue qsize10690367
Ref: 345a10690367
Ref: library/queue queue Queue empty10690596
Ref: 345b10690596
Ref: library/queue queue Queue full10690925
Ref: 345c10690925
Ref: library/queue queue Queue put10691250
Ref: 345710691250
Ref: library/queue queue Queue put_nowait10691902
Ref: 2ec010691902
Ref: library/queue queue Queue get10691989
Ref: 2ec110691989
Ref: library/queue queue Queue get_nowait10693019
Ref: 345610693019
Ref: library/queue queue Queue task_done10693212
Ref: 336410693212
Ref: library/queue queue Queue join10693844
Ref: 336510693844
Node: Waiting for task completion10694339
Ref: library/queue waiting-for-task-completion10694443
Ref: 345d10694443
Node: Terminating queues10695097
Ref: library/queue terminating-queues10695201
Ref: 345e10695201
Ref: library/queue queue Queue shutdown10695387
Ref: 23a10695387
Node: SimpleQueue Objects10696792
Ref: library/queue simplequeue-objects10696906
Ref: 345f10696906
Ref: library/queue queue SimpleQueue qsize10697042
Ref: 346010697042
Ref: library/queue queue SimpleQueue empty10697208
Ref: 346110697208
Ref: library/queue queue SimpleQueue put10697425
Ref: 346210697425
Ref: library/queue queue SimpleQueue put_nowait10698190
Ref: 346310698190
Ref: library/queue queue SimpleQueue get10698352
Ref: 346410698352
Ref: library/queue queue SimpleQueue get_nowait10698927
Ref: 346510698927
Node: contextvars — Context Variables10699375
Ref: library/contextvars doc10699554
Ref: 346610699554
Ref: library/contextvars contextvars-context-variables10699554
Ref: 346710699554
Ref: library/contextvars module-contextvars10699554
Ref: 2410699554
Ref: library/contextvars translation-repo10699554
Ref: 346810699554
Ref: contextvars — Context Variables-Footnote-110700413
Node: Context Variables10700455
Ref: library/contextvars context-variables10700576
Ref: 346a10700576
Ref: library/contextvars contextvars ContextVar10700631
Ref: 166210700631
Ref: library/contextvars contextvars ContextVar name10701338
Ref: 346c10701338
Ref: library/contextvars contextvars ContextVar get10701467
Ref: 346b10701467
Ref: library/contextvars contextvars ContextVar set10701954
Ref: 15de10701954
Ref: library/contextvars contextvars ContextVar reset10702350
Ref: 346e10702350
Ref: library/contextvars contextvars Token10702921
Ref: 346d10702921
Ref: library/contextvars contextvars Token var10703264
Ref: 346f10703264
Ref: library/contextvars contextvars Token old_value10703402
Ref: 347010703402
Ref: library/contextvars contextvars Token MISSING10703694
Ref: 347110703694
Node: Manual Context Management10703787
Ref: library/contextvars manual-context-management10703932
Ref: 347210703932
Ref: library/contextvars contextvars copy_context10704003
Ref: 346910704003
Ref: library/contextvars contextvars Context10704481
Ref: 15dd10704481
Ref: library/contextvars contextvars Context run10706429
Ref: 171110706429
Ref: library/contextvars contextvars Context copy10707759
Ref: 347310707759
Ref: library/contextvars contextvars Context get10708202
Ref: 347410708202
Ref: library/contextvars contextvars Context keys10708644
Ref: 347510708644
Ref: library/contextvars contextvars Context values10708735
Ref: 347610708735
Ref: library/contextvars contextvars Context items10708838
Ref: 347710708838
Node: asyncio support10708977
Ref: library/contextvars asyncio-support10709096
Ref: 347810709096
Node: _thread — Low-level threading API10710791
Ref: library/_thread doc10710925
Ref: 347910710925
Ref: library/_thread module-_thread10710925
Ref: 210710925
Ref: library/_thread thread-low-level-threading-api10710925
Ref: 347a10710925
Ref: library/_thread translation-repo10710925
Ref: 347b10710925
Ref: library/_thread thread error10711641
Ref: 347c10711641
Ref: library/_thread thread LockType10711809
Ref: 347d10711809
Ref: library/_thread thread start_new_thread10711877
Ref: 19610711877
Ref: library/_thread thread interrupt_main10712906
Ref: 84910712906
Ref: library/_thread thread exit10713825
Ref: 347e10713825
Ref: library/_thread thread allocate_lock10713974
Ref: 347f10713974
Ref: library/_thread thread get_ident10714122
Ref: 348010714122
Ref: library/_thread thread get_native_id10714488
Ref: 348110714488
Ref: library/_thread thread stack_size10715040
Ref: 348210715040
Ref: library/_thread thread TIMEOUT_MAX10716314
Ref: 348310716314
Ref: library/_thread thread lock acquire10716599
Ref: 348410716599
Ref: library/_thread thread lock release10717676
Ref: 348510717676
Ref: library/_thread thread lock locked10717818
Ref: 348610717818
Node: Networking and Interprocess Communication10719055
Ref: library/ipc doc10719220
Ref: 348710719220
Ref: library/ipc ipc10719220
Ref: 348810719220
Ref: library/ipc networking-and-interprocess-communication10719220
Ref: 348910719220
Ref: library/ipc translation-repo10719220
Ref: 348a10719220
Node: asyncio — Asynchronous I/O10720017
Ref: library/asyncio doc10720173
Ref: 348b10720173
Ref: library/asyncio asyncio-asynchronous-i-o10720173
Ref: 348c10720173
Ref: library/asyncio module-asyncio10720173
Ref: a10720173
Ref: library/asyncio asyncio-cli10721913
Ref: 349810721913
Node: Runners10723121
Ref: library/asyncio-runner doc10723222
Ref: 349910723222
Ref: library/asyncio-runner runners10723222
Ref: 349a10723222
Ref: Runners-Footnote-110723640
Node: Running an asyncio Program10723716
Ref: library/asyncio-runner running-an-asyncio-program10723817
Ref: 349b10723817
Ref: library/asyncio-runner asyncio run10723890
Ref: 47f10723890
Node: Runner context manager10725628
Ref: library/asyncio-runner runner-context-manager10725768
Ref: 349d10725768
Ref: library/asyncio-runner asyncio Runner10725833
Ref: 60310725833
Ref: library/asyncio-runner asyncio Runner run10726983
Ref: 17be10726983
Ref: library/asyncio-runner asyncio Runner close10727495
Ref: 349e10727495
Ref: library/asyncio-runner asyncio Runner get_loop10727718
Ref: 349f10727718
Node: Handling Keyboard Interruption10728154
Ref: library/asyncio-runner handling-keyboard-interruption10728259
Ref: 34a010728259
Node: Coroutines and tasks10729769
Ref: library/asyncio-task doc10729886
Ref: 34a110729886
Ref: library/asyncio-task coroutines-and-tasks10729886
Ref: 34a210729886
Ref: library/asyncio-task translation-repo10729886
Ref: 34a310729886
Node: Coroutines<3>10730366
Ref: library/asyncio-task coroutine10730455
Ref: 348e10730455
Ref: library/asyncio-task coroutines10730455
Ref: 34a410730455
Ref: Coroutines<3>-Footnote-110733760
Node: Awaitables10733839
Ref: library/asyncio-task asyncio-awaitables10733951
Ref: 34a510733951
Ref: library/asyncio-task awaitables10733951
Ref: 34a610733951
Node: Creating tasks10736550
Ref: library/asyncio-task creating-tasks10736666
Ref: 34a710736666
Ref: library/asyncio-task asyncio create_task10736823
Ref: 1bf10736823
Ref: Creating tasks-Footnote-110738860
Node: Task cancellation10738933
Ref: library/asyncio-task task-cancellation10739050
Ref: 34a810739050
Node: Task groups10740108
Ref: library/asyncio-task task-groups10740219
Ref: 34a910740219
Ref: library/asyncio-task taskgroups10740219
Ref: 34aa10740219
Ref: library/asyncio-task asyncio TaskGroup10740386
Ref: 1b510740386
Ref: library/asyncio-task asyncio TaskGroup create_task10740651
Ref: 1bc10740651
Node: Terminating a task group10744625
Ref: library/asyncio-task terminating-a-task-group10744697
Ref: 34ab10744697
Node: Sleeping10746026
Ref: library/asyncio-task sleeping10746146
Ref: 34ac10746146
Ref: library/asyncio-task asyncio sleep10746185
Ref: a7e10746185
Ref: library/asyncio-task asyncio-example-sleep10746672
Ref: 34ad10746672
Node: Running tasks concurrently10747334
Ref: library/asyncio-task running-tasks-concurrently10747461
Ref: 34ae10747461
Ref: library/asyncio-task asyncio gather10747536
Ref: 60010747536
Ref: library/asyncio-task asyncio-example-gather10749260
Ref: 34af10749260
Node: Eager task factory10751376
Ref: library/asyncio-task eager-task-factory10751522
Ref: 34b010751522
Ref: library/asyncio-task id110751522
Ref: 34b110751522
Ref: library/asyncio-task asyncio eager_task_factory10751581
Ref: 47a10751581
Ref: library/asyncio-task asyncio create_eager_task_factory10752727
Ref: 47b10752727
Node: Shielding from cancellation10753407
Ref: library/asyncio-task shielding-from-cancellation10753535
Ref: 34b210753535
Ref: library/asyncio-task asyncio shield10753612
Ref: a7f10753612
Node: Timeouts10755290
Ref: library/asyncio-task timeouts10755418
Ref: 34b310755418
Ref: library/asyncio-task asyncio timeout10755457
Ref: 60110755457
Ref: library/asyncio-task asyncio Timeout10757194
Ref: 17da10757194
Ref: library/asyncio-task asyncio Timeout when10757836
Ref: 34b510757836
Ref: library/asyncio-task asyncio Timeout reschedule10758008
Ref: 34b410758008
Ref: library/asyncio-task asyncio Timeout expired10758113
Ref: 34b610758113
Ref: library/asyncio-task asyncio timeout_at10758953
Ref: 195810758953
Ref: library/asyncio-task asyncio wait_for10759568
Ref: 60210759568
Ref: library/asyncio-task asyncio-example-waitfor10760364
Ref: 34b710760364
Node: Waiting primitives10761204
Ref: library/asyncio-task waiting-primitives10761323
Ref: 34b810761323
Ref: library/asyncio-task asyncio wait10761382
Ref: 48210761382
Ref: library/asyncio-task asyncio FIRST_COMPLETED10762583
Ref: 34b910762583
Ref: library/asyncio-task asyncio FIRST_EXCEPTION10762892
Ref: 34ba10762892
Ref: library/asyncio-task asyncio ALL_COMPLETED10763413
Ref: 34bb10763413
Ref: library/asyncio-task asyncio as_completed10763974
Ref: 1aa10763974
Node: Running in threads10766830
Ref: library/asyncio-task running-in-threads10766970
Ref: 34bc10766970
Ref: library/asyncio-task asyncio to_thread10767029
Ref: 8f110767029
Node: Scheduling from other threads10769239
Ref: library/asyncio-task scheduling-from-other-threads10769374
Ref: 34bd10769374
Ref: library/asyncio-task asyncio run_coroutine_threadsafe10769455
Ref: 88910769455
Node: Introspection10770883
Ref: library/asyncio-task introspection10771011
Ref: 34bf10771011
Ref: library/asyncio-task asyncio current_task10771060
Ref: 48010771060
Ref: library/asyncio-task asyncio all_tasks10771339
Ref: 96010771339
Ref: library/asyncio-task asyncio iscoroutine10771599
Ref: 48110771599
Node: Task object10771724
Ref: library/asyncio-task asyncio-task-obj10771814
Ref: 34c010771814
Ref: library/asyncio-task task-object10771814
Ref: 34c110771814
Ref: library/asyncio-task asyncio Task10771859
Ref: 1be10771859
Ref: library/asyncio-task asyncio Task done10774639
Ref: 34c410774639
Ref: library/asyncio-task asyncio Task result10774855
Ref: 34c510774855
Ref: library/asyncio-task asyncio Task exception10775344
Ref: 34c710775344
Ref: library/asyncio-task asyncio Task add_done_callback10775831
Ref: 34c810775831
Ref: library/asyncio-task asyncio Task remove_done_callback10776146
Ref: 34c910776146
Ref: library/asyncio-task asyncio Task get_stack10776444
Ref: 34ca10776444
Ref: library/asyncio-task asyncio Task print_stack10777440
Ref: 187310777440
Ref: library/asyncio-task asyncio Task get_coro10777932
Ref: 9e710777932
Ref: library/asyncio-task asyncio Task get_context10778341
Ref: 34cb10778341
Ref: library/asyncio-task asyncio Task get_name10778506
Ref: 9e910778506
Ref: library/asyncio-task asyncio Task set_name10778780
Ref: 9e810778780
Ref: library/asyncio-task asyncio Task cancel10779116
Ref: 1b710779116
Ref: library/asyncio-task asyncio-example-task-cancel10780309
Ref: 34cc10780309
Ref: library/asyncio-task asyncio Task cancelled10781564
Ref: 34c210781564
Ref: library/asyncio-task asyncio Task uncancel10781863
Ref: 1bb10781863
Ref: library/asyncio-task asyncio Task cancelling10784161
Ref: 1ba10784161
Node: Streams10784971
Ref: library/asyncio-stream doc10785107
Ref: 34cd10785107
Ref: library/asyncio-stream asyncio-streams10785107
Ref: 348f10785107
Ref: library/asyncio-stream streams10785107
Ref: 34ce10785107
Ref: library/asyncio-stream translation-repo10785107
Ref: 34cf10785107
Ref: library/asyncio-stream asyncio-example-stream10785444
Ref: 34d010785444
Ref: library/asyncio-stream asyncio open_connection10786190
Ref: b3110786190
Ref: library/asyncio-stream asyncio start_server10787495
Ref: b3210787495
Ref: library/asyncio-stream asyncio open_unix_connection10789102
Ref: 34d410789102
Ref: library/asyncio-stream asyncio start_unix_server10790076
Ref: 34d610790076
Ref: Streams-Footnote-110791435
Node: StreamReader10791511
Ref: library/asyncio-stream streamreader10791588
Ref: 34d710791588
Ref: library/asyncio-stream asyncio StreamReader10791635
Ref: 15b610791635
Ref: library/asyncio-stream asyncio StreamReader feed_eof10792021
Ref: 34d810792021
Ref: library/asyncio-stream asyncio StreamReader read10792083
Ref: 34d910792083
Ref: library/asyncio-stream asyncio StreamReader readline10792712
Ref: 34da10792712
Ref: library/asyncio-stream asyncio StreamReader readexactly10793064
Ref: c9d10793064
Ref: library/asyncio-stream asyncio StreamReader readuntil10793356
Ref: 1b410793356
Ref: library/asyncio-stream asyncio StreamReader at_eof10794648
Ref: 34dd10794648
Node: StreamWriter10794778
Ref: library/asyncio-stream streamwriter10794876
Ref: 34de10794876
Ref: library/asyncio-stream asyncio StreamWriter10794923
Ref: 180f10794923
Ref: library/asyncio-stream asyncio StreamWriter write10795205
Ref: 34df10795205
Ref: library/asyncio-stream asyncio StreamWriter writelines10795695
Ref: 34e010795695
Ref: library/asyncio-stream asyncio StreamWriter close10796088
Ref: 34d210796088
Ref: library/asyncio-stream asyncio StreamWriter can_write_eof10796368
Ref: 34e110796368
Ref: library/asyncio-stream asyncio StreamWriter write_eof10796539
Ref: 34e210796539
Ref: library/asyncio-stream asyncio StreamWriter transport10796667
Ref: 34e310796667
Ref: library/asyncio-stream asyncio StreamWriter get_extra_info10796750
Ref: 34e410796750
Ref: library/asyncio-stream asyncio StreamWriter drain10796924
Ref: 18cc10796924
Ref: library/asyncio-stream asyncio StreamWriter start_tls10797506
Ref: 60710797506
Ref: library/asyncio-stream asyncio StreamWriter is_closing10798519
Ref: b2610798519
Ref: library/asyncio-stream asyncio StreamWriter wait_closed10798682
Ref: b2510798682
Node: Examples<15>10798998
Ref: library/asyncio-stream examples10799075
Ref: 34d110799075
Node: TCP echo client using streams10799272
Ref: library/asyncio-stream asyncio-tcp-echo-client-streams10799388
Ref: 34e510799388
Ref: library/asyncio-stream tcp-echo-client-using-streams10799388
Ref: 34e610799388
Node: TCP echo server using streams10800176
Ref: library/asyncio-stream asyncio-tcp-echo-server-streams10800317
Ref: 34e810800317
Ref: library/asyncio-stream tcp-echo-server-using-streams10800317
Ref: 34e910800317
Node: Get HTTP headers10801359
Ref: library/asyncio-stream get-http-headers10801525
Ref: 34eb10801525
Node: Register an open socket to wait for data using streams10802796
Ref: library/asyncio-stream asyncio-example-create-connection-streams10802924
Ref: 34ec10802924
Ref: library/asyncio-stream register-an-open-socket-to-wait-for-data-using-streams10802924
Ref: 34ed10802924
Node: Synchronization Primitives10804349
Ref: library/asyncio-sync doc10804477
Ref: 34f110804477
Ref: library/asyncio-sync asyncio-sync10804477
Ref: 349210804477
Ref: library/asyncio-sync synchronization-primitives10804477
Ref: 34f210804477
Ref: library/asyncio-sync translation-repo10804477
Ref: 34f310804477
Ref: Synchronization Primitives-Footnote-110805554
Node: Lock10805627
Ref: library/asyncio-sync lock10805708
Ref: 34f410805708
Ref: library/asyncio-sync asyncio Lock10805739
Ref: a8010805739
Ref: library/asyncio-sync asyncio Lock acquire10806401
Ref: 34f510806401
Ref: library/asyncio-sync asyncio Lock release10806884
Ref: 34f610806884
Ref: library/asyncio-sync asyncio Lock locked10807101
Ref: 34f710807101
Node: Event10807183
Ref: library/asyncio-sync event10807282
Ref: 34f810807282
Ref: library/asyncio-sync asyncio Event10807315
Ref: a8110807315
Ref: library/asyncio-sync asyncio-example-sync-event10807844
Ref: 34fc10807844
Ref: library/asyncio-sync asyncio Event wait10808473
Ref: 34fb10808473
Ref: library/asyncio-sync asyncio Event set10808679
Ref: 34f910808679
Ref: library/asyncio-sync asyncio Event clear10808819
Ref: 34fa10808819
Ref: library/asyncio-sync asyncio Event is_set10809020
Ref: 34fd10809020
Node: Condition10809098
Ref: library/asyncio-sync condition10809202
Ref: 34fe10809202
Ref: library/asyncio-sync asyncio Condition10809243
Ref: a8210809243
Ref: library/asyncio-sync asyncio Condition acquire10810475
Ref: 34ff10810475
Ref: library/asyncio-sync asyncio Condition notify10810674
Ref: 178d10810674
Ref: library/asyncio-sync asyncio Condition locked10811038
Ref: 350010811038
Ref: library/asyncio-sync asyncio Condition notify_all10811131
Ref: 350110811131
Ref: library/asyncio-sync asyncio Condition release10811509
Ref: 350210811509
Ref: library/asyncio-sync asyncio Condition wait10811671
Ref: 17b810811671
Ref: library/asyncio-sync asyncio Condition wait_for10812404
Ref: 350310812404
Node: Semaphore10812752
Ref: library/asyncio-sync semaphore10812867
Ref: 350410812867
Ref: library/asyncio-sync asyncio Semaphore10812908
Ref: a8310812908
Ref: library/asyncio-sync asyncio Semaphore acquire10814007
Ref: 17b910814007
Ref: library/asyncio-sync asyncio Semaphore locked10814291
Ref: 350610814291
Ref: library/asyncio-sync asyncio Semaphore release10814395
Ref: 350510814395
Node: BoundedSemaphore10814703
Ref: library/asyncio-sync boundedsemaphore10814816
Ref: 350710814816
Ref: library/asyncio-sync asyncio BoundedSemaphore10814871
Ref: a8410814871
Node: Barrier10815230
Ref: library/asyncio-sync barrier10815325
Ref: 350810815325
Ref: library/asyncio-sync asyncio Barrier10815362
Ref: 60410815362
Ref: library/asyncio-sync asyncio-example-barrier10815947
Ref: 350a10815947
Ref: library/asyncio-sync asyncio Barrier wait10816815
Ref: 350910816815
Ref: library/asyncio-sync asyncio Barrier reset10817892
Ref: 350b10817892
Ref: library/asyncio-sync asyncio Barrier abort10818188
Ref: 350c10818188
Ref: library/asyncio-sync asyncio Barrier parties10818501
Ref: 350d10818501
Ref: library/asyncio-sync asyncio Barrier n_waiting10818591
Ref: 350e10818591
Ref: library/asyncio-sync asyncio Barrier broken10818711
Ref: 350f10818711
Ref: library/asyncio-sync asyncio BrokenBarrierError10818828
Ref: 60510818828
Node: Subprocesses10819298
Ref: library/asyncio-subprocess doc10819425
Ref: 351010819425
Ref: library/asyncio-subprocess asyncio-subprocess10819425
Ref: 349010819425
Ref: library/asyncio-subprocess subprocesses10819425
Ref: 351110819425
Ref: library/asyncio-subprocess translation-repo10819425
Ref: 351210819425
Ref: library/asyncio-subprocess asyncio-example-subprocess-shell10819713
Ref: 351310819713
Ref: Subprocesses-Footnote-110821009
Ref: Subprocesses-Footnote-210821088
Node: Creating Subprocesses10821172
Ref: library/asyncio-subprocess creating-subprocesses10821263
Ref: 351510821263
Ref: library/asyncio-subprocess asyncio create_subprocess_exec10821328
Ref: a8610821328
Ref: library/asyncio-subprocess asyncio create_subprocess_shell10822047
Ref: a8710822047
Ref: Creating Subprocesses-Footnote-110823712
Node: Constants<7>10823782
Ref: library/asyncio-subprocess constants10823911
Ref: 352010823911
Ref: library/asyncio-subprocess asyncio subprocess PIPE10823952
Ref: 352110823952
Ref: library/asyncio-subprocess asyncio subprocess STDOUT10824398
Ref: 352310824398
Ref: library/asyncio-subprocess asyncio subprocess DEVNULL10824584
Ref: 352410824584
Node: Interacting with Subprocesses10824865
Ref: library/asyncio-subprocess interacting-with-subprocesses10824964
Ref: 352510824964
Ref: library/asyncio-subprocess asyncio subprocess Process10825295
Ref: 351810825295
Ref: library/asyncio-subprocess asyncio subprocess Process wait10826273
Ref: 352610826273
Ref: library/asyncio-subprocess asyncio subprocess Process communicate10826778
Ref: 183f10826778
Ref: library/asyncio-subprocess asyncio subprocess Process send_signal10828137
Ref: 170110828137
Ref: library/asyncio-subprocess asyncio subprocess Process terminate10828551
Ref: 352910828551
Ref: library/asyncio-subprocess asyncio subprocess Process kill10828833
Ref: 352a10828833
Ref: library/asyncio-subprocess asyncio subprocess Process stdin10829077
Ref: 352210829077
Ref: library/asyncio-subprocess asyncio subprocess Process stdout10829239
Ref: 351610829239
Ref: library/asyncio-subprocess asyncio subprocess Process stderr10829404
Ref: 351710829404
Ref: library/asyncio-subprocess asyncio subprocess Process pid10829909
Ref: 352b10829909
Ref: library/asyncio-subprocess asyncio subprocess Process returncode10830148
Ref: 352810830148
Node: Subprocess and Threads10830928
Ref: library/asyncio-subprocess asyncio-subprocess-threads10831037
Ref: 352710831037
Ref: library/asyncio-subprocess subprocess-and-threads10831037
Ref: 352c10831037
Node: Examples<16>10831905
Ref: library/asyncio-subprocess examples10832014
Ref: 351410832014
Ref: library/asyncio-subprocess asyncio-example-create-subprocess-exec10832198
Ref: 352e10832198
Node: Queues10833001
Ref: library/asyncio-queue doc10833116
Ref: 353010833116
Ref: library/asyncio-queue asyncio-queues10833116
Ref: 349110833116
Ref: library/asyncio-queue queues10833116
Ref: 353110833116
Ref: library/asyncio-queue translation-repo10833116
Ref: 353210833116
Ref: Queues-Footnote-110833808
Node: Queue10833882
Ref: library/asyncio-queue queue10833953
Ref: 353410833953
Ref: library/asyncio-queue asyncio Queue10833986
Ref: a8510833986
Ref: library/asyncio-queue asyncio Queue maxsize10834595
Ref: 353710834595
Ref: library/asyncio-queue asyncio Queue empty10834673
Ref: 353810834673
Ref: library/asyncio-queue asyncio Queue full10834775
Ref: 353910834775
Ref: library/asyncio-queue asyncio Queue get10835024
Ref: 353510835024
Ref: library/asyncio-queue asyncio Queue get_nowait10835329
Ref: 353a10835329
Ref: library/asyncio-queue asyncio Queue join10835465
Ref: df610835465
Ref: library/asyncio-queue asyncio Queue put10835943
Ref: 353c10835943
Ref: library/asyncio-queue asyncio Queue put_nowait10836197
Ref: 353d10836197
Ref: library/asyncio-queue asyncio Queue qsize10836381
Ref: 353610836381
Ref: library/asyncio-queue asyncio Queue shutdown10836460
Ref: 1b010836460
Ref: library/asyncio-queue asyncio Queue task_done10838000
Ref: df710838000
Node: Priority Queue10838686
Ref: library/asyncio-queue priority-queue10838776
Ref: 353f10838776
Ref: library/asyncio-queue asyncio PriorityQueue10838827
Ref: 354010838827
Node: LIFO Queue10839034
Ref: library/asyncio-queue lifo-queue10839133
Ref: 354110839133
Ref: library/asyncio-queue asyncio LifoQueue10839176
Ref: 354210839176
Node: Exceptions<12>10839319
Ref: library/asyncio-queue exceptions10839416
Ref: 354310839416
Ref: library/asyncio-queue asyncio QueueEmpty10839459
Ref: 353b10839459
Ref: library/asyncio-queue asyncio QueueFull10839601
Ref: 353e10839601
Ref: library/asyncio-queue asyncio QueueShutDown10839758
Ref: 1b110839758
Node: Examples<17>10839946
Ref: library/asyncio-queue examples10840024
Ref: 353310840024
Ref: library/asyncio-queue asyncio-example-queue-dist10840063
Ref: 354410840063
Node: Exceptions<13>10841821
Ref: library/asyncio-exceptions doc10841934
Ref: 354510841934
Ref: library/asyncio-exceptions asyncio-exceptions10841934
Ref: 354610841934
Ref: library/asyncio-exceptions exceptions10841934
Ref: 354710841934
Ref: library/asyncio-exceptions translation-repo10841934
Ref: 354810841934
Ref: library/asyncio-exceptions asyncio TimeoutError10842090
Ref: 185810842090
Ref: library/asyncio-exceptions asyncio CancelledError10842327
Ref: 1b810842327
Ref: library/asyncio-exceptions asyncio InvalidStateError10842710
Ref: 34c610842710
Ref: library/asyncio-exceptions asyncio SendfileNotAvailableError10842949
Ref: 354910842949
Ref: library/asyncio-exceptions asyncio IncompleteReadError10843134
Ref: 1a8f10843134
Ref: library/asyncio-exceptions asyncio IncompleteReadError expected10843350
Ref: 354a10843350
Ref: library/asyncio-exceptions asyncio IncompleteReadError partial10843445
Ref: 34db10843445
Ref: library/asyncio-exceptions asyncio LimitOverrunError10843568
Ref: 34dc10843568
Ref: library/asyncio-exceptions asyncio LimitOverrunError consumed10843730
Ref: 354b10843730
Ref: Exceptions<13>-Footnote-110843849
Node: Event loop10843928
Ref: library/asyncio-eventloop doc10844042
Ref: 354c10844042
Ref: library/asyncio-eventloop asyncio-event-loop10844042
Ref: da410844042
Ref: library/asyncio-eventloop event-loop10844042
Ref: 354d10844042
Ref: library/asyncio-eventloop translation-repo10844042
Ref: 354e10844042
Ref: library/asyncio-eventloop asyncio get_running_loop10844872
Ref: b2410844872
Ref: library/asyncio-eventloop asyncio get_event_loop10845150
Ref: 2c210845150
Ref: library/asyncio-eventloop asyncio set_event_loop10846142
Ref: 18fa10846142
Ref: library/asyncio-eventloop asyncio new_event_loop10846257
Ref: 349c10846257
Ref: Event loop-Footnote-110847536
Ref: Event loop-Footnote-210847610
Node: Event loop methods10847690
Ref: library/asyncio-eventloop asyncio-event-loop-methods10847780
Ref: 355510847780
Ref: library/asyncio-eventloop event-loop-methods10847780
Ref: 355010847780
Node: Running and stopping the loop10848363
Ref: library/asyncio-eventloop running-and-stopping-the-loop10848476
Ref: 355610848476
Ref: library/asyncio-eventloop asyncio loop run_until_complete10848557
Ref: c9910848557
Ref: library/asyncio-eventloop asyncio loop run_forever10848873
Ref: 355710848873
Ref: library/asyncio-eventloop asyncio loop stop10849571
Ref: c9e10849571
Ref: library/asyncio-eventloop asyncio loop is_running10849624
Ref: 355810849624
Ref: library/asyncio-eventloop asyncio loop is_closed10849720
Ref: df210849720
Ref: library/asyncio-eventloop asyncio loop close10849805
Ref: 355910849805
Ref: library/asyncio-eventloop asyncio loop shutdown_asyncgens10850210
Ref: ca010850210
Ref: library/asyncio-eventloop asyncio loop shutdown_default_executor10850891
Ref: 8f010850891
Node: Scheduling callbacks10851903
Ref: library/asyncio-eventloop scheduling-callbacks10852053
Ref: 355a10852053
Ref: library/asyncio-eventloop asyncio loop call_soon10852116
Ref: b1d10852116
Ref: library/asyncio-eventloop asyncio loop call_soon_threadsafe10852829
Ref: b1e10852829
Ref: library/asyncio-eventloop asyncio-pass-keywords10853646
Ref: 355b10853646
Ref: Scheduling callbacks-Footnote-110854141
Node: Scheduling delayed callbacks10854183
Ref: library/asyncio-eventloop asyncio-delayed-calls10854330
Ref: 355c10854330
Ref: library/asyncio-eventloop scheduling-delayed-callbacks10854330
Ref: 355d10854330
Ref: library/asyncio-eventloop asyncio loop call_later10854563
Ref: b1f10854563
Ref: library/asyncio-eventloop asyncio loop call_at10855928
Ref: b2010855928
Ref: library/asyncio-eventloop asyncio loop time10856886
Ref: 355e10856886
Ref: Scheduling delayed callbacks-Footnote-110857321
Ref: Scheduling delayed callbacks-Footnote-210857363
Node: Creating futures and tasks10857405
Ref: library/asyncio-eventloop creating-futures-and-tasks10857559
Ref: 355f10857559
Ref: library/asyncio-eventloop asyncio loop create_future10857634
Ref: c9b10857634
Ref: library/asyncio-eventloop asyncio loop create_task10857992
Ref: 1c010857992
Ref: library/asyncio-eventloop asyncio loop set_task_factory10859456
Ref: df410859456
Ref: library/asyncio-eventloop asyncio loop get_task_factory10860231
Ref: df510860231
Node: Opening network connections10860341
Ref: library/asyncio-eventloop opening-network-connections10860491
Ref: 356010860491
Ref: library/asyncio-eventloop asyncio loop create_connection10860568
Ref: 60610860568
Ref: library/asyncio-eventloop asyncio loop create_datagram_endpoint10867485
Ref: 73610867485
Ref: library/asyncio-eventloop asyncio loop create_unix_connection10871343
Ref: 34d510871343
Ref: Opening network connections-Footnote-110872398
Ref: Opening network connections-Footnote-210872457
Node: Creating network servers10872516
Ref: library/asyncio-eventloop creating-network-servers10872658
Ref: 356810872658
Ref: library/asyncio-eventloop loop-create-server10872729
Ref: 349310872729
Ref: library/asyncio-eventloop asyncio loop create_server10872729
Ref: b2c10872729
Ref: library/asyncio-eventloop asyncio loop create_unix_server10877424
Ref: 1ae10877424
Ref: library/asyncio-eventloop asyncio loop connect_accepted_socket10878680
Ref: 7e210878680
Node: Transferring files10880240
Ref: library/asyncio-eventloop transferring-files10880366
Ref: 356a10880366
Ref: library/asyncio-eventloop asyncio loop sendfile10880425
Ref: 356b10880425
Node: TLS upgrade10881481
Ref: library/asyncio-eventloop tls-upgrade10881608
Ref: 356c10881608
Ref: library/asyncio-eventloop asyncio loop start_tls10881653
Ref: b2210881653
Node: Watching file descriptors10883593
Ref: library/asyncio-eventloop watching-file-descriptors10883738
Ref: 356d10883738
Ref: library/asyncio-eventloop asyncio loop add_reader10883811
Ref: 34f010883811
Ref: library/asyncio-eventloop asyncio loop remove_reader10884126
Ref: 356e10884126
Ref: library/asyncio-eventloop asyncio loop add_writer10884307
Ref: 356f10884307
Ref: library/asyncio-eventloop asyncio loop remove_writer10884731
Ref: 357010884731
Node: Working with socket objects directly10885001
Ref: library/asyncio-eventloop working-with-socket-objects-directly10885138
Ref: 357210885138
Ref: library/asyncio-eventloop asyncio loop sock_recv10885589
Ref: c3110885589
Ref: library/asyncio-eventloop asyncio loop sock_recv_into10886054
Ref: b2310886054
Ref: library/asyncio-eventloop asyncio loop sock_recvfrom10886360
Ref: 60910886360
Ref: library/asyncio-eventloop asyncio loop sock_recvfrom_into10886661
Ref: 60a10886661
Ref: library/asyncio-eventloop asyncio loop sock_sendall10886999
Ref: c3210886999
Ref: library/asyncio-eventloop asyncio loop sock_sendto10887751
Ref: 60810887751
Ref: library/asyncio-eventloop asyncio loop sock_connect10888027
Ref: df810888027
Ref: library/asyncio-eventloop asyncio loop sock_accept10888644
Ref: c3310888644
Ref: library/asyncio-eventloop asyncio loop sock_sendfile10889464
Ref: b2710889464
Node: DNS10890664
Ref: library/asyncio-eventloop dns10890794
Ref: 357310890794
Ref: library/asyncio-eventloop asyncio loop getaddrinfo10890823
Ref: c3410890823
Ref: library/asyncio-eventloop asyncio loop getnameinfo10890985
Ref: c3510890985
Node: Working with pipes10891823
Ref: library/asyncio-eventloop working-with-pipes10891929
Ref: 357410891929
Ref: library/asyncio-eventloop asyncio loop connect_read_pipe10891988
Ref: 351c10891988
Ref: library/asyncio-eventloop asyncio loop connect_write_pipe10892559
Ref: 351d10892559
Node: Unix signals10893392
Ref: library/asyncio-eventloop unix-signals10893536
Ref: 357710893536
Ref: library/asyncio-eventloop loop-add-signal-handler10893583
Ref: 349510893583
Ref: library/asyncio-eventloop asyncio loop add_signal_handler10893583
Ref: 357810893583
Ref: library/asyncio-eventloop asyncio loop remove_signal_handler10894418
Ref: 357910894418
Node: Executing code in thread or process pools10894723
Ref: library/asyncio-eventloop executing-code-in-thread-or-process-pools10894867
Ref: 357a10894867
Ref: library/asyncio-eventloop asyncio loop run_in_executor10894972
Ref: 8f210894972
Ref: library/asyncio-eventloop asyncio loop set_default_executor10897695
Ref: 74610897695
Node: Error handling API10898005
Ref: library/asyncio-eventloop error-handling-api10898156
Ref: 357b10898156
Ref: library/asyncio-eventloop asyncio loop set_exception_handler10898281
Ref: 357c10898281
Ref: library/asyncio-eventloop asyncio loop get_exception_handler10899137
Ref: c9c10899137
Ref: library/asyncio-eventloop asyncio loop default_exception_handler10899313
Ref: 357e10899313
Ref: library/asyncio-eventloop asyncio loop call_exception_handler10899688
Ref: 357d10899688
Node: Enabling debug mode10900893
Ref: library/asyncio-eventloop enabling-debug-mode10901023
Ref: 357f10901023
Ref: library/asyncio-eventloop asyncio loop get_debug10901084
Ref: df110901084
Ref: library/asyncio-eventloop asyncio loop set_debug10901339
Ref: df010901339
Ref: library/asyncio-eventloop asyncio loop slow_callback_duration10901553
Ref: 358010901553
Node: Running subprocesses10901882
Ref: library/asyncio-eventloop running-subprocesses10901985
Ref: 358110901985
Ref: library/asyncio-eventloop loop-subprocess-exec10902511
Ref: 349410902511
Ref: library/asyncio-eventloop asyncio loop subprocess_exec10902511
Ref: 351910902511
Ref: library/asyncio-eventloop asyncio loop subprocess_shell10906555
Ref: 351a10906555
Ref: Running subprocesses-Footnote-110907986
Node: Callback handles10908056
Ref: library/asyncio-eventloop callback-handles10908169
Ref: 355110908169
Ref: library/asyncio-eventloop asyncio Handle10908224
Ref: 1c3510908224
Ref: library/asyncio-eventloop asyncio Handle get_context10908369
Ref: 358410908369
Ref: library/asyncio-eventloop asyncio Handle cancel10908536
Ref: 358510908536
Ref: library/asyncio-eventloop asyncio Handle cancelled10908689
Ref: b3310908689
Ref: library/asyncio-eventloop asyncio TimerHandle10908813
Ref: 188010908813
Ref: library/asyncio-eventloop asyncio TimerHandle when10909009
Ref: b3010909009
Node: Server objects10909256
Ref: library/asyncio-eventloop server-objects10909377
Ref: 355210909377
Ref: library/asyncio-eventloop asyncio Server10909664
Ref: b2b10909664
Ref: library/asyncio-eventloop asyncio Server close10910354
Ref: 34d310910354
Ref: library/asyncio-eventloop asyncio Server close_clients10910783
Ref: 1b210910783
Ref: library/asyncio-eventloop asyncio Server abort_clients10911145
Ref: 1b310911145
Ref: library/asyncio-eventloop asyncio Server get_loop10911581
Ref: b2a10911581
Ref: library/asyncio-eventloop asyncio Server start_serving10911712
Ref: b2d10911712
Ref: library/asyncio-eventloop asyncio Server serve_forever10912328
Ref: b2e10912328
Ref: library/asyncio-eventloop asyncio Server is_serving10913223
Ref: b2f10913223
Ref: library/asyncio-eventloop asyncio Server wait_closed10913361
Ref: 17d910913361
Ref: library/asyncio-eventloop asyncio Server sockets10913516
Ref: c3610913516
Ref: library/asyncio-eventloop asyncio-event-loops10913863
Ref: 358710913863
Node: Event loop implementations10913863
Ref: library/asyncio-eventloop asyncio-event-loop-implementations10913980
Ref: 358810913980
Ref: library/asyncio-eventloop event-loop-implementations10913980
Ref: 355310913980
Ref: library/asyncio-eventloop asyncio SelectorEventLoop10914245
Ref: 60b10914245
Ref: library/asyncio-eventloop asyncio ProactorEventLoop10914919
Ref: 60c10914919
Ref: library/asyncio-eventloop asyncio EventLoop10915193
Ref: 180610915193
Ref: library/asyncio-eventloop asyncio AbstractEventLoop10915503
Ref: 96910915503
Ref: Event loop implementations-Footnote-110915799
Node: Examples<18>10915878
Ref: library/asyncio-eventloop examples10915972
Ref: 355410915972
Node: Hello World with call_soon10916571
Ref: library/asyncio-eventloop asyncio-example-lowlevel-helloworld10916695
Ref: 358910916695
Ref: library/asyncio-eventloop hello-world-with-call-soon10916695
Ref: 358a10916695
Node: Display the current date with call_later10917469
Ref: library/asyncio-eventloop asyncio-example-call-later10917641
Ref: 358b10917641
Ref: library/asyncio-eventloop display-the-current-date-with-call-later10917641
Ref: 358c10917641
Node: Watch a file descriptor for read events10918633
Ref: library/asyncio-eventloop asyncio-example-watch-fd10918821
Ref: 34ef10918821
Ref: library/asyncio-eventloop watch-a-file-descriptor-for-read-events10918821
Ref: 358d10918821
Node: Set signal handlers for SIGINT and SIGTERM10920141
Ref: library/asyncio-eventloop asyncio-example-unix-signals10920280
Ref: 358e10920280
Ref: library/asyncio-eventloop set-signal-handlers-for-sigint-and-sigterm10920280
Ref: 358f10920280
Node: Futures10921208
Ref: library/asyncio-future doc10921332
Ref: 33de10921332
Ref: library/asyncio-future asyncio-futures10921332
Ref: 349710921332
Ref: library/asyncio-future futures10921332
Ref: 359010921332
Ref: library/asyncio-future translation-repo10921332
Ref: 359110921332
Ref: Futures-Footnote-110921699
Ref: Futures-Footnote-210921775
Node: Future Functions10921856
Ref: library/asyncio-future future-functions10921938
Ref: 359210921938
Ref: library/asyncio-future asyncio isfuture10921993
Ref: 359310921993
Ref: library/asyncio-future asyncio ensure_future10922301
Ref: c9810922301
Ref: library/asyncio-future asyncio wrap_future10923534
Ref: 1a2310923534
Node: Future Object10923878
Ref: library/asyncio-future asyncio-future-obj10923960
Ref: 359410923960
Ref: library/asyncio-future future-object10923960
Ref: 359510923960
Ref: library/asyncio-future asyncio Future10924009
Ref: bec10924009
Ref: library/asyncio-future asyncio Future result10925136
Ref: 359610925136
Ref: library/asyncio-future asyncio Future set_result10925751
Ref: 34c310925751
Ref: library/asyncio-future asyncio Future set_exception10925947
Ref: c9f10925947
Ref: library/asyncio-future asyncio Future done10926151
Ref: 359710926151
Ref: library/asyncio-future asyncio Future cancelled10926414
Ref: 359810926414
Ref: library/asyncio-future asyncio Future add_done_callback10926719
Ref: b2110926719
Ref: library/asyncio-future asyncio Future remove_done_callback10927708
Ref: 16a910927708
Ref: library/asyncio-future asyncio Future cancel10927940
Ref: 194f10927940
Ref: library/asyncio-future asyncio Future exception10928293
Ref: 359910928293
Ref: library/asyncio-future asyncio Future get_loop10928737
Ref: b2910928737
Ref: library/asyncio-future asyncio-example-future10928864
Ref: 359a10928864
Ref: Future Object-Footnote-110931073
Node: Transports and Protocols10931115
Ref: library/asyncio-protocol doc10931237
Ref: 359b10931237
Ref: library/asyncio-protocol asyncio-transports-protocols10931237
Ref: 349610931237
Ref: library/asyncio-protocol translation-repo10931237
Ref: 359c10931237
Ref: library/asyncio-protocol transports-and-protocols10931237
Ref: 359d10931237
Node: Transports10933604
Ref: library/asyncio-protocol asyncio-transport10933693
Ref: 356210933693
Ref: library/asyncio-protocol transports10933693
Ref: 359e10933693
Ref: Transports-Footnote-110934435
Node: Transports Hierarchy10934514
Ref: library/asyncio-protocol transports-hierarchy10934604
Ref: 35a510934604
Ref: library/asyncio-protocol asyncio BaseTransport10934667
Ref: 35a010934667
Ref: library/asyncio-protocol asyncio WriteTransport10934796
Ref: 357610934796
Ref: library/asyncio-protocol asyncio ReadTransport10935127
Ref: 357510935127
Ref: library/asyncio-protocol asyncio Transport10935454
Ref: 35a110935454
Ref: library/asyncio-protocol asyncio DatagramTransport10936057
Ref: 18ca10936057
Ref: library/asyncio-protocol asyncio SubprocessTransport10936300
Ref: 358310936300
Node: Base Transport10936626
Ref: library/asyncio-protocol base-transport10936745
Ref: 35a610936745
Ref: library/asyncio-protocol asyncio BaseTransport close10936796
Ref: 356510936796
Ref: library/asyncio-protocol asyncio BaseTransport is_closing10937225
Ref: c9a10937225
Ref: library/asyncio-protocol asyncio BaseTransport get_extra_info10937332
Ref: ab110937332
Ref: library/asyncio-protocol asyncio BaseTransport set_protocol10939490
Ref: 35ab10939490
Ref: library/asyncio-protocol asyncio BaseTransport get_protocol10939675
Ref: 35ac10939675
Node: Read-only Transports10939753
Ref: library/asyncio-protocol read-only-transports10939873
Ref: 35ad10939873
Ref: library/asyncio-protocol asyncio ReadTransport is_reading10939936
Ref: b3410939936
Ref: library/asyncio-protocol asyncio ReadTransport pause_reading10940069
Ref: b3610940069
Ref: library/asyncio-protocol asyncio ReadTransport resume_reading10940438
Ref: b3510940438
Node: Write-only Transports10940776
Ref: library/asyncio-protocol write-only-transports10940901
Ref: 35ae10940901
Ref: library/asyncio-protocol asyncio WriteTransport abort10940966
Ref: 358610940966
Ref: library/asyncio-protocol asyncio WriteTransport can_write_eof10941305
Ref: 35af10941305
Ref: library/asyncio-protocol asyncio WriteTransport get_write_buffer_size10941462
Ref: 35b110941462
Ref: library/asyncio-protocol asyncio WriteTransport get_write_buffer_limits10941589
Ref: df310941589
Ref: library/asyncio-protocol asyncio WriteTransport set_write_buffer_limits10941905
Ref: 35b210941905
Ref: library/asyncio-protocol asyncio WriteTransport write10943317
Ref: 160110943317
Ref: library/asyncio-protocol asyncio WriteTransport writelines10943516
Ref: 160010943516
Ref: library/asyncio-protocol asyncio WriteTransport write_eof10943800
Ref: 35b010943800
Node: Datagram Transports10944089
Ref: library/asyncio-protocol datagram-transports10944215
Ref: 35b510944215
Ref: library/asyncio-protocol asyncio DatagramTransport sendto10944276
Ref: 1af10944276
Ref: library/asyncio-protocol asyncio DatagramTransport abort10944888
Ref: 35b610944888
Node: Subprocess Transports10945230
Ref: library/asyncio-protocol asyncio-subprocess-transports10945326
Ref: 351e10945326
Ref: library/asyncio-protocol subprocess-transports10945326
Ref: 35b710945326
Ref: library/asyncio-protocol asyncio SubprocessTransport get_pid10945391
Ref: 35b810945391
Ref: library/asyncio-protocol asyncio SubprocessTransport get_pipe_transport10945489
Ref: 35b910945489
Ref: library/asyncio-protocol asyncio SubprocessTransport get_returncode10946235
Ref: 35ba10946235
Ref: library/asyncio-protocol asyncio SubprocessTransport kill10946470
Ref: 35bb10946470
Ref: library/asyncio-protocol asyncio SubprocessTransport send_signal10946731
Ref: 35bd10946731
Ref: library/asyncio-protocol asyncio SubprocessTransport terminate10946890
Ref: 35bc10946890
Ref: library/asyncio-protocol asyncio SubprocessTransport close10947209
Ref: 35be10947209
Node: Protocols10947435
Ref: library/asyncio-protocol asyncio-protocol10947545
Ref: 356110947545
Ref: library/asyncio-protocol protocols10947545
Ref: 359f10947545
Ref: Protocols-Footnote-110948338
Node: Base Protocols10948416
Ref: library/asyncio-protocol base-protocols10948498
Ref: 35bf10948498
Ref: library/asyncio-protocol asyncio BaseProtocol10948549
Ref: 35a210948549
Ref: library/asyncio-protocol asyncio Protocol10948641
Ref: 35a310948641
Ref: library/asyncio-protocol asyncio BufferedProtocol10948774
Ref: ab210948774
Ref: library/asyncio-protocol asyncio DatagramProtocol10948930
Ref: 6d210948930
Ref: library/asyncio-protocol asyncio SubprocessProtocol10949046
Ref: 358210949046
Node: Base Protocol10949212
Ref: library/asyncio-protocol base-protocol10949322
Ref: 35c010949322
Ref: library/asyncio-protocol asyncio BaseProtocol connection_made10949645
Ref: 356310949645
Ref: library/asyncio-protocol asyncio BaseProtocol connection_lost10949899
Ref: 35a710949899
Ref: library/asyncio-protocol asyncio BaseProtocol pause_writing10950442
Ref: 35b310950442
Ref: library/asyncio-protocol asyncio BaseProtocol resume_writing10950558
Ref: 35b410950558
Node: Streaming Protocols10951022
Ref: library/asyncio-protocol streaming-protocols10951146
Ref: 35c110951146
Ref: library/asyncio-protocol asyncio Protocol data_received10951556
Ref: 18a510951556
Ref: library/asyncio-protocol asyncio Protocol eof_received10952237
Ref: 35c210952237
Node: Buffered Streaming Protocols10953101
Ref: library/asyncio-protocol buffered-streaming-protocols10953230
Ref: 35c310953230
Ref: library/asyncio-protocol asyncio BufferedProtocol get_buffer10953923
Ref: 35c410953923
Ref: library/asyncio-protocol asyncio BufferedProtocol buffer_updated10954396
Ref: 35c510954396
Ref: library/asyncio-protocol asyncio BufferedProtocol eof_received10954597
Ref: 35c610954597
Node: Datagram Protocols10955162
Ref: library/asyncio-protocol datagram-protocols10955292
Ref: 35c710955292
Ref: library/asyncio-protocol asyncio DatagramProtocol datagram_received10955490
Ref: 35c810955490
Ref: library/asyncio-protocol asyncio DatagramProtocol error_received10955755
Ref: 35c910955755
Node: Subprocess Protocols10956684
Ref: library/asyncio-protocol asyncio-subprocess-protocols10956777
Ref: 351f10956777
Ref: library/asyncio-protocol subprocess-protocols10956777
Ref: 35ca10956777
Ref: library/asyncio-protocol asyncio SubprocessProtocol pipe_data_received10957015
Ref: 18f410957015
Ref: library/asyncio-protocol asyncio SubprocessProtocol pipe_connection_lost10957288
Ref: 35cb10957288
Ref: library/asyncio-protocol asyncio SubprocessProtocol process_exited10957498
Ref: 18f310957498
Node: Examples<19>10957714
Ref: library/asyncio-protocol examples10957805
Ref: 35a410957805
Node: TCP Echo Server10958060
Ref: library/asyncio-protocol asyncio-example-tcp-echo-server-protocol10958148
Ref: 34ea10958148
Ref: library/asyncio-protocol tcp-echo-server10958148
Ref: 35cc10958148
Node: TCP Echo Client10959422
Ref: library/asyncio-protocol asyncio-example-tcp-echo-client-protocol10959534
Ref: 34e710959534
Ref: library/asyncio-protocol tcp-echo-client10959534
Ref: 35cd10959534
Node: UDP Echo Server10961092
Ref: library/asyncio-protocol asyncio-udp-echo-server-protocol10961204
Ref: 356710961204
Ref: library/asyncio-protocol udp-echo-server10961204
Ref: 35ce10961204
Node: UDP Echo Client10962340
Ref: library/asyncio-protocol asyncio-udp-echo-client-protocol10962464
Ref: 356610962464
Ref: library/asyncio-protocol udp-echo-client10962464
Ref: 35cf10962464
Node: Connecting Existing Sockets10963996
Ref: library/asyncio-protocol asyncio-example-create-connection10964148
Ref: 34ee10964148
Ref: library/asyncio-protocol connecting-existing-sockets10964148
Ref: 35d010964148
Node: loop subprocess_exec and SubprocessProtocol10966062
Ref: library/asyncio-protocol asyncio-example-subprocess-proto10966190
Ref: 352f10966190
Ref: library/asyncio-protocol loop-subprocess-exec-and-subprocessprotocol10966190
Ref: 35d110966190
Node: Policies10968501
Ref: library/asyncio-policy doc10968632
Ref: 35d210968632
Ref: library/asyncio-policy asyncio-policies10968632
Ref: 354f10968632
Ref: library/asyncio-policy policies10968632
Ref: 35d310968632
Ref: library/asyncio-policy translation-repo10968632
Ref: 35d410968632
Node: Getting and Setting the Policy10969563
Ref: library/asyncio-policy asyncio-policy-get-set10969661
Ref: 35d510969661
Ref: library/asyncio-policy getting-and-setting-the-policy10969661
Ref: 35da10969661
Ref: library/asyncio-policy asyncio get_event_loop_policy10969834
Ref: 35db10969834
Ref: library/asyncio-policy asyncio set_event_loop_policy10969928
Ref: 35dc10969928
Node: Policy Objects10970109
Ref: library/asyncio-policy asyncio-policy-objects10970232
Ref: 35d810970232
Ref: library/asyncio-policy policy-objects10970232
Ref: 35dd10970232
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy10970351
Ref: 35d910970351
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy get_event_loop10970446
Ref: 35de10970446
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy set_event_loop10970734
Ref: 35df10970734
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy new_event_loop10970839
Ref: 35e010970839
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy get_child_watcher10970984
Ref: 2c110970984
Ref: library/asyncio-policy asyncio AbstractEventLoopPolicy set_child_watcher10971261
Ref: 2c010971261
Ref: library/asyncio-policy asyncio-policy-builtin10971455
Ref: 35d610971455
Ref: library/asyncio-policy asyncio DefaultEventLoopPolicy10971508
Ref: 35e110971508
Ref: library/asyncio-policy asyncio WindowsSelectorEventLoopPolicy10972209
Ref: 35e210972209
Ref: library/asyncio-policy asyncio WindowsProactorEventLoopPolicy10972417
Ref: 35e310972417
Node: Process Watchers10972625
Ref: library/asyncio-policy asyncio-watchers10972733
Ref: 352d10972733
Ref: library/asyncio-policy process-watchers10972733
Ref: 35e410972733
Ref: library/asyncio-policy asyncio get_child_watcher10973601
Ref: 2bf10973601
Ref: library/asyncio-policy asyncio set_child_watcher10973745
Ref: 2be10973745
Ref: library/asyncio-policy asyncio AbstractChildWatcher10974212
Ref: 2bc10974212
Ref: library/asyncio-policy asyncio AbstractChildWatcher add_child_handler10974253
Ref: 35e510974253
Ref: library/asyncio-policy asyncio AbstractChildWatcher remove_child_handler10974646
Ref: 35e610974646
Ref: library/asyncio-policy asyncio AbstractChildWatcher attach_loop10974897
Ref: 18fb10974897
Ref: library/asyncio-policy asyncio AbstractChildWatcher is_active10975161
Ref: 35e710975161
Ref: library/asyncio-policy asyncio AbstractChildWatcher close10975399
Ref: 35e810975399
Ref: library/asyncio-policy asyncio ThreadedChildWatcher10975595
Ref: 47e10975595
Ref: library/asyncio-policy asyncio MultiLoopChildWatcher10976067
Ref: 2ba10976067
Ref: library/asyncio-policy asyncio SafeChildWatcher10976767
Ref: 2bd10976767
Ref: library/asyncio-policy asyncio FastChildWatcher10977394
Ref: 2bb10977394
Ref: library/asyncio-policy asyncio PidfdChildWatcher10977898
Ref: 47c10977898
Node: Custom Policies10978490
Ref: library/asyncio-policy asyncio-custom-policies10978575
Ref: 35d710978575
Ref: library/asyncio-policy custom-policies10978575
Ref: 35e910978575
Node: Platform Support10979184
Ref: library/asyncio-platforms doc10979300
Ref: 35ea10979300
Ref: library/asyncio-platforms asyncio-platform-support10979300
Ref: 357110979300
Ref: library/asyncio-platforms platform-support10979300
Ref: 35eb10979300
Ref: library/asyncio-platforms translation-repo10979300
Ref: 35ec10979300
Node: All Platforms10979612
Ref: library/asyncio-platforms all-platforms10979698
Ref: 35ed10979698
Node: Windows<82>10979862
Ref: library/asyncio-platforms windows10979966
Ref: 35ee10979966
Ref: Windows<82>-Footnote-110981811
Ref: Windows<82>-Footnote-210981895
Ref: Windows<82>-Footnote-310981978
Ref: Windows<82>-Footnote-410982060
Node: Subprocess Support on Windows10982125
Ref: library/asyncio-platforms asyncio-windows-subprocess10982202
Ref: 351b10982202
Ref: library/asyncio-platforms subprocess-support-on-windows10982202
Ref: 35f010982202
Node: macOS<52>10982583
Ref: library/asyncio-platforms macos10982665
Ref: 35f110982665
Node: Extending10983296
Ref: library/asyncio-extending doc10983424
Ref: 35f310983424
Ref: library/asyncio-extending extending10983424
Ref: 35f410983424
Ref: library/asyncio-extending translation-repo10983424
Ref: 35f510983424
Node: Writing a Custom Event Loop10983904
Ref: library/asyncio-extending writing-a-custom-event-loop10984022
Ref: 35f610984022
Node: Future and Task private constructors10984741
Ref: library/asyncio-extending future-and-task-private-constructors10984889
Ref: 35f710984889
Ref: library/asyncio-extending asyncio Future __init__10985453
Ref: 35f810985453
Ref: library/asyncio-extending asyncio Task __init__10985587
Ref: 35f910985587
Node: Task lifetime support10985897
Ref: library/asyncio-extending task-lifetime-support10986009
Ref: 35fa10986009
Ref: library/asyncio-extending asyncio _register_task10986245
Ref: 35fb10986245
Ref: library/asyncio-extending asyncio _unregister_task10986392
Ref: 35fc10986392
Ref: library/asyncio-extending asyncio _enter_task10986569
Ref: 35fd10986569
Ref: library/asyncio-extending asyncio _leave_task10986827
Ref: 35fe10986827
Node: High-level API Index10987051
Ref: library/asyncio-api-index doc10987182
Ref: 88010987182
Ref: library/asyncio-api-index high-level-api-index10987182
Ref: 35ff10987182
Ref: library/asyncio-api-index translation-repo10987182
Ref: 360010987182
Node: Tasks10987460
Ref: library/asyncio-api-index tasks10987540
Ref: 360110987540
Node: Queues<2>10991680
Ref: library/asyncio-api-index queues10991784
Ref: 360210991784
Node: Subprocesses<2>10992603
Ref: library/asyncio-api-index subprocesses10992712
Ref: 360310992712
Node: Streams<2>10993274
Ref: library/asyncio-api-index streams10993389
Ref: 360410993389
Node: Synchronization10994824
Ref: library/asyncio-api-index synchronization10994938
Ref: 360510994938
Node: Exceptions<14>10996301
Ref: library/asyncio-api-index exceptions10996396
Ref: 360610996396
Node: Low-level API Index10997146
Ref: library/asyncio-llapi-index doc10997291
Ref: 360710997291
Ref: library/asyncio-llapi-index low-level-api-index10997291
Ref: 360810997291
Ref: library/asyncio-llapi-index translation-repo10997291
Ref: 360910997291
Node: Obtaining the Event Loop10997541
Ref: library/asyncio-llapi-index obtaining-the-event-loop10997648
Ref: 360a10997648
Node: Event Loop Methods10998777
Ref: library/asyncio-llapi-index event-loop-methods10998906
Ref: 360b10998906
Node: Transports<2>11011234
Ref: library/asyncio-llapi-index transports11011351
Ref: 360c11011351
Node: Protocols<2>11017396
Ref: library/asyncio-llapi-index protocols11017514
Ref: 360d11017514
Node: Event Loop Policies11021255
Ref: library/asyncio-llapi-index event-loop-policies11021351
Ref: 360e11021351
Node: Developing with asyncio11022180
Ref: library/asyncio-dev doc11022296
Ref: 360f11022296
Ref: library/asyncio-dev asyncio-dev11022296
Ref: 361011022296
Ref: library/asyncio-dev developing-with-asyncio11022296
Ref: 361111022296
Ref: library/asyncio-dev translation-repo11022296
Ref: 361211022296
Node: Debug Mode11022750
Ref: library/asyncio-dev asyncio-debug-mode11022859
Ref: 1ef211022859
Ref: library/asyncio-dev debug-mode11022859
Ref: 361311022859
Node: Concurrency and Multithreading11024357
Ref: library/asyncio-dev asyncio-multithreading11024496
Ref: 34be11024496
Ref: library/asyncio-dev concurrency-and-multithreading11024496
Ref: 361511024496
Node: Running Blocking Code11026779
Ref: library/asyncio-dev asyncio-handle-blocking11026918
Ref: 361611026918
Ref: library/asyncio-dev running-blocking-code11026918
Ref: 361711026918
Node: Logging<3>11027412
Ref: library/asyncio-dev asyncio-logger11027552
Ref: 361411027552
Ref: library/asyncio-dev logging11027552
Ref: 361811027552
Node: Detect never-awaited coroutines11028031
Ref: library/asyncio-dev asyncio-coroutine-not-scheduled11028183
Ref: 361a11028183
Ref: library/asyncio-dev detect-never-awaited-coroutines11028183
Ref: 361b11028183
Node: Detect never-retrieved exceptions11029192
Ref: library/asyncio-dev detect-never-retrieved-exceptions11029372
Ref: 361c11029372
Node: Asynchronous generators best practices11030872
Ref: library/asyncio-dev asynchronous-generators-best-practices11031012
Ref: 361d11031012
Node: Close asynchronous generators explicitly11031474
Ref: library/asyncio-dev close-asynchronous-generators-explicitly11031664
Ref: 361e11031664
Node: Create asynchronous generators only when the event loop is running11034428
Ref: library/asyncio-dev create-asynchronous-generators-only-when-the-event-loop-is-running11034687
Ref: 362011034687
Node: Avoid concurrent iteration and closure of the same generator11036752
Ref: library/asyncio-dev avoid-concurrent-iteration-and-closure-of-the-same-generator11036962
Ref: 362111036962
Ref: Avoid concurrent iteration and closure of the same generator-Footnote-111038783
Node: socket — Low-level networking interface11038848
Ref: library/socket doc11039055
Ref: 362211039055
Ref: library/socket module-socket11039055
Ref: cc11039055
Ref: library/socket socket-low-level-networking-interface11039055
Ref: 362311039055
Ref: library/socket translation-repo11039055
Ref: 362411039055
Ref: socket — Low-level networking interface-Footnote-111040552
Node: Socket families11040618
Ref: library/socket socket-addresses11040738
Ref: 362511040738
Ref: library/socket socket-families11040738
Ref: 362611040738
Ref: library/socket host-port11041934
Ref: 362711041934
Ref: Socket families-Footnote-111052471
Ref: Socket families-Footnote-211052513
Node: Module contents<2>11052558
Ref: library/socket module-contents11052701
Ref: 362e11052701
Node: Exceptions<15>11052903
Ref: library/socket exceptions11052993
Ref: 362f11052993
Ref: library/socket socket error11053034
Ref: 109311053034
Ref: library/socket socket herror11053221
Ref: 363011053221
Ref: library/socket socket gaierror11053846
Ref: 186711053846
Ref: library/socket socket timeout11054451
Ref: 83a11054451
Ref: Exceptions<15>-Footnote-111055092
Node: Constants<8>11055134
Ref: library/socket constants11055245
Ref: 363211055245
Ref: library/socket socket AF_UNIX11055420
Ref: 195511055420
Ref: library/socket socket AF_INET11055445
Ref: 195311055445
Ref: library/socket socket AF_INET611055470
Ref: 195411055470
Ref: library/socket socket AF_UNSPEC11055784
Ref: 356911055784
Ref: library/socket socket SOCK_STREAM11055995
Ref: 133c11055995
Ref: library/socket socket SOCK_DGRAM11056024
Ref: 133b11056024
Ref: library/socket socket SOCK_RAW11056052
Ref: 363311056052
Ref: library/socket socket SOCK_RDM11056078
Ref: 363411056078
Ref: library/socket socket SOCK_SEQPACKET11056104
Ref: 363511056104
Ref: library/socket socket SOCK_CLOEXEC11056405
Ref: c2b11056405
Ref: library/socket socket SOCK_NONBLOCK11056435
Ref: c2a11056435
Ref: library/socket socket-unix-constants11056852
Ref: b9111056852
Ref: library/socket socket SOMAXCONN11056867
Ref: e9311056867
Ref: library/socket socket AF_CAN11059482
Ref: 362811059482
Ref: library/socket socket PF_CAN11059506
Ref: 363611059506
Ref: library/socket socket CAN_BCM11059927
Ref: fdc11059927
Ref: library/socket socket CAN_RAW_FD_FRAMES11060352
Ref: efe11060352
Ref: library/socket socket CAN_RAW_JOIN_FILTERS11060768
Ref: 93b11060768
Ref: library/socket socket CAN_ISOTP11061070
Ref: 362911061070
Ref: library/socket socket CAN_J193911061322
Ref: 93c11061322
Ref: library/socket socket AF_DIVERT11061558
Ref: 363711061558
Ref: library/socket socket PF_DIVERT11061585
Ref: 363811061585
Ref: library/socket socket AF_PACKET11061812
Ref: 362a11061812
Ref: library/socket socket PF_PACKET11061839
Ref: 363911061839
Ref: library/socket socket ETH_P_ALL11062054
Ref: 18c611062054
Ref: library/socket socket AF_RDS11062404
Ref: 363a11062404
Ref: library/socket socket PF_RDS11062428
Ref: 363b11062428
Ref: library/socket socket SOL_RDS11062452
Ref: 363c11062452
Ref: library/socket socket SIO_RCVALL11062693
Ref: 363d11062693
Ref: library/socket socket SIO_KEEPALIVE_VALS11062721
Ref: 363e11062721
Ref: library/socket socket SIO_LOOPBACK_FAST_PATH11062757
Ref: cfa11062757
Ref: library/socket socket AF_ALG11063176
Ref: cfd11063176
Ref: library/socket socket SOL_ALG11063200
Ref: 363f11063200
Ref: library/socket socket AF_VSOCK11063368
Ref: b9211063368
Ref: library/socket socket IOCTL_VM_SOCKETS_GET_LOCAL_CID11063394
Ref: 364011063394
Ref: library/socket socket AF_LINK11063607
Ref: fdd11063607
Ref: library/socket socket has_ipv611063706
Ref: 364111063706
Ref: library/socket socket BDADDR_ANY11063838
Ref: 364211063838
Ref: library/socket socket BDADDR_LOCAL11063866
Ref: 364311063866
Ref: library/socket socket HCI_FILTER11064135
Ref: 364411064135
Ref: library/socket socket HCI_TIME_STAMP11064163
Ref: 364511064163
Ref: library/socket socket HCI_DATA_DIR11064195
Ref: 364611064195
Ref: library/socket socket AF_QIPCRTR11064405
Ref: 362b11064405
Ref: library/socket socket SCM_CREDS211064601
Ref: 364711064601
Ref: library/socket socket LOCAL_CREDS11064629
Ref: 364811064629
Ref: library/socket socket LOCAL_CREDS_PERSISTENT11064658
Ref: 364911064658
Ref: library/socket socket SO_INCOMING_CPU11065096
Ref: 364a11065096
Ref: library/socket socket AF_HYPERV11065302
Ref: 362c11065302
Ref: library/socket socket HV_PROTOCOL_RAW11065329
Ref: 364b11065329
Ref: library/socket socket HVSOCKET_CONNECT_TIMEOUT11065362
Ref: 364c11065362
Ref: library/socket socket HVSOCKET_CONNECT_TIMEOUT_MAX11065404
Ref: 364d11065404
Ref: library/socket socket HVSOCKET_CONNECTED_SUSPEND11065450
Ref: 364e11065450
Ref: library/socket socket HVSOCKET_ADDRESS_FLAG_PASSTHRU11065494
Ref: 364f11065494
Ref: library/socket socket HV_GUID_ZERO11065542
Ref: 365011065542
Ref: library/socket socket HV_GUID_WILDCARD11065572
Ref: 365111065572
Ref: library/socket socket HV_GUID_BROADCAST11065606
Ref: 365211065606
Ref: library/socket socket HV_GUID_CHILDREN11065641
Ref: 365311065641
Ref: library/socket socket HV_GUID_LOOPBACK11065675
Ref: 365411065675
Ref: library/socket socket HV_GUID_PARENT11065709
Ref: 365511065709
Ref: library/socket socket-ethernet-types11065893
Ref: 18c711065893
Ref: library/socket socket ETHERTYPE_ARP11065893
Ref: 365611065893
Ref: library/socket socket ETHERTYPE_IP11065924
Ref: 365711065924
Ref: library/socket socket ETHERTYPE_IPV611065954
Ref: 365811065954
Ref: library/socket socket ETHERTYPE_VLAN11065986
Ref: 365911065986
Ref: library/socket socket SHUT_RD11066153
Ref: 365a11066153
Ref: library/socket socket SHUT_WR11066178
Ref: 365b11066178
Ref: library/socket socket SHUT_RDWR11066203
Ref: 365c11066203
Ref: Constants<8>-Footnote-111066403
Ref: Constants<8>-Footnote-211066455
Ref: Constants<8>-Footnote-311066501
Node: Functions<8>11066581
Ref: library/socket functions11066669
Ref: 365e11066669
Node: Creating sockets11066778
Ref: library/socket creating-sockets11066870
Ref: 365f11066870
Ref: library/socket socket socket11066987
Ref: dcf11066987
Ref: library/socket socket socketpair11069558
Ref: c1611069558
Ref: library/socket socket create_connection11070284
Ref: 67511070284
Ref: library/socket socket create_server11071792
Ref: a3811071792
Ref: library/socket socket has_dualstack_ipv611073621
Ref: a3911073621
Ref: library/socket socket fromfd11073818
Ref: 366111073818
Ref: library/socket socket fromshare11074701
Ref: c2711074701
Ref: library/socket socket SocketType11074957
Ref: 366311074957
Node: Other functions<2>11075110
Ref: library/socket other-functions11075202
Ref: 366411075202
Ref: library/socket socket close11075324
Ref: b8f11075324
Ref: library/socket socket getaddrinfo11075589
Ref: 15ba11075589
Ref: library/socket socket getfqdn11079684
Ref: 189011079684
Ref: library/socket socket gethostbyname11080301
Ref: 366511080301
Ref: library/socket socket gethostbyname_ex11080937
Ref: 1a2b11080937
Ref: library/socket socket gethostname11081720
Ref: 2d2311081720
Ref: library/socket socket gethostbyaddr11082143
Ref: 1a2a11082143
Ref: library/socket socket getnameinfo11082877
Ref: 17d311082877
Ref: library/socket socket getprotobyname11083649
Ref: 366611083649
Ref: library/socket socket getservbyname11084146
Ref: 366711084146
Ref: library/socket socket getservbyport11084601
Ref: 366811084601
Ref: library/socket socket ntohl11085042
Ref: 366911085042
Ref: library/socket socket ntohs11085299
Ref: 88711085299
Ref: library/socket socket htonl11085675
Ref: 366a11085675
Ref: library/socket socket htons11085932
Ref: 88611085932
Ref: library/socket socket inet_aton11086308
Ref: 96b11086308
Ref: library/socket socket inet_ntoa11087222
Ref: 366b11087222
Ref: library/socket socket inet_pton11088037
Ref: 96c11088037
Ref: library/socket socket inet_ntop11088820
Ref: fde11088820
Ref: library/socket socket CMSG_LEN11089793
Ref: 1bc711089793
Ref: library/socket socket CMSG_SPACE11090475
Ref: 1bc611090475
Ref: library/socket socket getdefaulttimeout11091364
Ref: 366211091364
Ref: library/socket socket setdefaulttimeout11091642
Ref: 363111091642
Ref: library/socket socket sethostname11091930
Ref: 117f11091930
Ref: library/socket socket if_nameindex11092277
Ref: a3a11092277
Ref: library/socket socket if_nametoindex11093079
Ref: a3b11093079
Ref: library/socket socket if_indextoname11093541
Ref: a3c11093541
Ref: library/socket socket send_fds11094005
Ref: 93d11094005
Ref: library/socket socket recv_fds11094480
Ref: 93e11094480
Ref: Other functions<2>-Footnote-111095065
Ref: Other functions<2>-Footnote-211095118
Ref: Other functions<2>-Footnote-311095169
Ref: Other functions<2>-Footnote-411095213
Node: Socket Objects11095272
Ref: library/socket id111095424
Ref: 366c11095424
Ref: library/socket socket-objects11095424
Ref: 366011095424
Ref: library/socket socket socket accept11095777
Ref: dd011095777
Ref: library/socket socket socket bind11096543
Ref: 158a11096543
Ref: library/socket socket socket close11096907
Ref: d6c11096907
Ref: library/socket socket socket connect11097876
Ref: dd111097876
Ref: library/socket socket socket connect_ex11099011
Ref: 158911099011
Ref: library/socket socket socket detach11099634
Ref: 126211099634
Ref: library/socket socket socket dup11099877
Ref: 366d11099877
Ref: library/socket socket socket fileno11100102
Ref: 366e11100102
Ref: library/socket socket socket get_inheritable11100463
Ref: f3511100463
Ref: library/socket socket socket getpeername11100727
Ref: 35a811100727
Ref: library/socket socket socket getsockname11101086
Ref: 35a911101086
Ref: library/socket socket socket getsockopt11101360
Ref: cfb11101360
Ref: library/socket socket socket getblocking11102112
Ref: b8e11102112
Ref: library/socket socket socket gettimeout11102336
Ref: 366f11102336
Ref: library/socket socket socket ioctl11102583
Ref: cf911102583
Ref: library/socket socket socket listen11103215
Ref: e9211103215
Ref: library/socket socket socket makefile11103684
Ref: 11e311103684
Ref: library/socket socket socket recv11104806
Ref: dd211104806
Ref: library/socket socket socket recvfrom11105513
Ref: dd311105513
Ref: library/socket socket socket recvmsg11106480
Ref: dd411106480
Ref: library/socket socket socket recvmsg_into11110369
Ref: 117e11110369
Ref: library/socket socket socket recvfrom_into11111999
Ref: 136811111999
Ref: library/socket socket socket recv_into11112557
Ref: 136711112557
Ref: library/socket socket socket send11113008
Ref: dd511113008
Ref: library/socket socket socket sendall11113811
Ref: dd611113811
Ref: library/socket socket socket sendto11114781
Ref: dd711114781
Ref: library/socket socket socket sendmsg11115627
Ref: 47911115627
Ref: library/socket socket socket sendmsg_afalg11117801
Ref: cfe11117801
Ref: library/socket socket socket sendfile11118135
Ref: e9111118135
Ref: library/socket socket socket set_inheritable11119036
Ref: f3611119036
Ref: library/socket socket socket setblocking11119218
Ref: 2d3a11119218
Ref: library/socket socket socket settimeout11119790
Ref: 362d11119790
Ref: library/socket socket socket setsockopt11120526
Ref: cfc11120526
Ref: library/socket socket socket shutdown11121603
Ref: 365d11121603
Ref: library/socket socket socket share11121960
Ref: c2811121960
Ref: library/socket socket socket family11122828
Ref: 367311122828
Ref: library/socket socket socket type11122883
Ref: c2c11122883
Ref: library/socket socket socket proto11122934
Ref: 367411122934
Ref: Socket Objects-Footnote-111123026
Ref: Socket Objects-Footnote-211123068
Ref: Socket Objects-Footnote-311123110
Ref: Socket Objects-Footnote-411123160
Ref: Socket Objects-Footnote-511123234
Ref: Socket Objects-Footnote-611123278
Ref: Socket Objects-Footnote-711123320
Ref: Socket Objects-Footnote-811123364
Ref: Socket Objects-Footnote-911123406
Ref: Socket Objects-Footnote-1011123448
Ref: Socket Objects-Footnote-1111123493
Ref: Socket Objects-Footnote-1211123538
Ref: Socket Objects-Footnote-1311123581
Ref: Socket Objects-Footnote-1411123624
Ref: Socket Objects-Footnote-1511123667
Ref: Socket Objects-Footnote-1611123710
Node: Notes on socket timeouts11123761
Ref: library/socket notes-on-socket-timeouts11123905
Ref: 367511123905
Ref: library/socket socket-timeouts11123905
Ref: 367211123905
Node: Timeouts and the connect method11125274
Ref: library/socket timeouts-and-the-connect-method11125405
Ref: 367611125405
Node: Timeouts and the accept method11125874
Ref: library/socket timeouts-and-the-accept-method11126005
Ref: 367711126005
Node: Example<7>11126746
Ref: library/socket example11126867
Ref: 367811126867
Ref: library/socket socket-example11126867
Ref: 367911126867
Ref: Example<7>-Footnote-111134581
Node: ssl — TLS/SSL wrapper for socket objects11134640
Ref: library/ssl doc11134856
Ref: 367a11134856
Ref: library/ssl module-ssl11134856
Ref: d011134856
Ref: library/ssl ssl-tls-ssl-wrapper-for-socket-objects11134856
Ref: 367b11134856
Ref: library/ssl translation-repo11134856
Ref: 367c11134856
Ref: ssl — TLS/SSL wrapper for socket objects-Footnote-111137869
Ref: ssl — TLS/SSL wrapper for socket objects-Footnote-211137932
Node: Functions constants and exceptions11137974
Ref: library/ssl functions-constants-and-exceptions11138107
Ref: 367d11138107
Node: Socket creation11138355
Ref: library/ssl socket-creation11138466
Ref: 367e11138466
Node: Context creation11139994
Ref: library/ssl context-creation11140128
Ref: 367f11140128
Ref: library/ssl ssl create_default_context11140270
Ref: 15511140270
Ref: Context creation-Footnote-111144264
Ref: Context creation-Footnote-211144323
Ref: Context creation-Footnote-311144368
Node: Exceptions<16>11144427
Ref: library/ssl exceptions11144563
Ref: 368411144563
Ref: library/ssl ssl SSLError11144604
Ref: 12c011144604
Ref: library/ssl ssl SSLError library11145165
Ref: 118b11145165
Ref: library/ssl ssl SSLError reason11145445
Ref: 118c11145445
Ref: library/ssl ssl SSLZeroReturnError11145706
Ref: 368511145706
Ref: library/ssl ssl SSLWantReadError11146003
Ref: e9d11146003
Ref: library/ssl ssl SSLWantWriteError11146313
Ref: e9e11146313
Ref: library/ssl ssl SSLSyscallError11146620
Ref: 368711146620
Ref: library/ssl ssl SSLEOFError11146912
Ref: 185c11146912
Ref: library/ssl ssl SSLCertVerificationError11147183
Ref: b9a11147183
Ref: library/ssl ssl SSLCertVerificationError verify_code11147350
Ref: 368811147350
Ref: library/ssl ssl SSLCertVerificationError verify_message11147454
Ref: 368911147454
Ref: library/ssl ssl CertificateError11147552
Ref: 368a11147552
Node: Random generation11147751
Ref: library/ssl random-generation11147891
Ref: 368b11147891
Ref: library/ssl ssl RAND_bytes11147946
Ref: 52711147946
Ref: library/ssl ssl RAND_status11148631
Ref: 1a2411148631
Ref: library/ssl ssl RAND_add11148951
Ref: 368c11148951
Ref: Random generation-Footnote-111149396
Ref: Random generation-Footnote-211149490
Node: Certificate handling11149549
Ref: library/ssl certificate-handling11149687
Ref: 368d11149687
Ref: library/ssl ssl cert_time_to_seconds11149748
Ref: e9f11149748
Ref: library/ssl ssl get_server_certificate11150664
Ref: 84211150664
Ref: library/ssl ssl DER_cert_to_PEM_cert11151837
Ref: 368f11151837
Ref: library/ssl ssl PEM_cert_to_DER_cert11152019
Ref: 369011152019
Ref: library/ssl ssl get_default_verify_paths11152199
Ref: fe311152199
Ref: library/ssl ssl enum_certificates11153076
Ref: fee11153076
Ref: library/ssl ssl enum_crls11153955
Ref: fef11153955
Ref: Certificate handling-Footnote-111154524
Node: Constants<9>11154583
Ref: library/ssl constants11154695
Ref: 369111154695
Ref: library/ssl ssl CERT_NONE11154861
Ref: 369211154861
Ref: library/ssl ssl CERT_OPTIONAL11155410
Ref: 369311155410
Ref: library/ssl ssl CERT_REQUIRED11156153
Ref: 368111156153
Ref: library/ssl ssl VerifyMode11157116
Ref: 369511157116
Ref: library/ssl ssl VERIFY_DEFAULT11157234
Ref: fe811157234
Ref: library/ssl ssl VERIFY_CRL_CHECK_LEAF11157489
Ref: fe911157489
Ref: library/ssl ssl VERIFY_CRL_CHECK_CHAIN11157936
Ref: fea11157936
Ref: library/ssl ssl VERIFY_X509_STRICT11158144
Ref: 15711158144
Ref: library/ssl ssl VERIFY_ALLOW_PROXY_CERTS11158326
Ref: 1a3b11158326
Ref: library/ssl ssl VERIFY_X509_TRUSTED_FIRST11158504
Ref: 369611158504
Ref: library/ssl ssl VERIFY_X509_PARTIAL_CHAIN11158795
Ref: 15611158795
Ref: library/ssl ssl VerifyFlags11159229
Ref: 369711159229
Ref: library/ssl ssl PROTOCOL_TLS11159350
Ref: 368311159350
Ref: library/ssl ssl PROTOCOL_TLS_CLIENT11159848
Ref: 87911159848
Ref: library/ssl ssl PROTOCOL_TLS_SERVER11160161
Ref: 87a11160161
Ref: library/ssl ssl PROTOCOL_SSLv2311160376
Ref: 369811160376
Ref: library/ssl ssl PROTOCOL_SSLv311160529
Ref: 368e11160529
Ref: library/ssl ssl PROTOCOL_TLSv111161108
Ref: 369911161108
Ref: library/ssl ssl PROTOCOL_TLSv1_111161300
Ref: fe111161300
Ref: library/ssl ssl PROTOCOL_TLSv1_211161571
Ref: fe211161571
Ref: library/ssl ssl OP_ALL11161842
Ref: 369a11161842
Ref: library/ssl ssl OP_NO_SSLv211162101
Ref: 83f11162101
Ref: library/ssl ssl OP_NO_SSLv311162404
Ref: 84011162404
Ref: library/ssl ssl OP_NO_TLSv111162707
Ref: 369b11162707
Ref: library/ssl ssl OP_NO_TLSv1_111163148
Ref: 369c11163148
Ref: library/ssl ssl OP_NO_TLSv1_211163537
Ref: 369d11163537
Ref: library/ssl ssl OP_NO_TLSv1_311163926
Ref: 1a0111163926
Ref: library/ssl ssl OP_NO_RENEGOTIATION11164514
Ref: 369e11164514
Ref: library/ssl ssl OP_CIPHER_SERVER_PREFERENCE11164797
Ref: 118d11164797
Ref: library/ssl ssl OP_SINGLE_DH_USE11165030
Ref: 369f11165030
Ref: library/ssl ssl OP_SINGLE_ECDH_USE11165285
Ref: 36a011165285
Ref: library/ssl ssl OP_ENABLE_MIDDLEBOX_COMPAT11165544
Ref: 36a111165544
Ref: library/ssl ssl OP_NO_COMPRESSION11165823
Ref: 118a11165823
Ref: library/ssl ssl Options11166016
Ref: 36a211166016
Ref: library/ssl ssl OP_NO_TICKET11166101
Ref: 36a311166101
Ref: library/ssl ssl OP_IGNORE_UNEXPECTED_EOF11166217
Ref: 83d11166217
Ref: library/ssl ssl OP_ENABLE_KTLS11166405
Ref: 18b211166405
Ref: library/ssl ssl OP_LEGACY_SERVER_CONNECT11167115
Ref: 189411167115
Ref: library/ssl ssl HAS_ALPN11167275
Ref: e9a11167275
Ref: library/ssl ssl HAS_NEVER_CHECK_COMMON_NAME11167484
Ref: 36a411167484
Ref: library/ssl ssl HAS_ECDH11167722
Ref: 36a511167722
Ref: library/ssl ssl HAS_SNI11167981
Ref: 36a611167981
Ref: library/ssl ssl HAS_NPN11168164
Ref: 36a711168164
Ref: library/ssl ssl HAS_SSLv211168517
Ref: 36a811168517
Ref: library/ssl ssl HAS_SSLv311168656
Ref: 36a911168656
Ref: library/ssl ssl HAS_TLSv111168795
Ref: 36aa11168795
Ref: library/ssl ssl HAS_TLSv1_111168934
Ref: ba111168934
Ref: library/ssl ssl HAS_TLSv1_211169075
Ref: 36ab11169075
Ref: library/ssl ssl HAS_TLSv1_311169216
Ref: 36ac11169216
Ref: library/ssl ssl HAS_PSK11169357
Ref: 36ad11169357
Ref: library/ssl ssl CHANNEL_BINDING_TYPES11169477
Ref: 36ae11169477
Ref: library/ssl ssl OPENSSL_VERSION11169698
Ref: 126411169698
Ref: library/ssl ssl OPENSSL_VERSION_INFO11169912
Ref: 126511169912
Ref: library/ssl ssl OPENSSL_VERSION_NUMBER11170140
Ref: 126611170140
Ref: library/ssl ssl ALERT_DESCRIPTION_HANDSHAKE_FAILURE11170411
Ref: 36af11170411
Ref: library/ssl ssl ALERT_DESCRIPTION_INTERNAL_ERROR11170461
Ref: 36b011170461
Ref: library/ssl ssl AlertDescription11170855
Ref: 36b111170855
Ref: library/ssl ssl Purpose SERVER_AUTH11170997
Ref: fec11170997
Ref: library/ssl ssl Purpose CLIENT_AUTH11171312
Ref: fed11171312
Ref: library/ssl ssl SSLErrorNumber11171627
Ref: 36b211171627
Ref: library/ssl ssl TLSVersion11171754
Ref: 36b311171754
Ref: library/ssl ssl TLSVersion MINIMUM_SUPPORTED11171971
Ref: 36b411171971
Ref: library/ssl ssl TLSVersion MAXIMUM_SUPPORTED11172016
Ref: 36b511172016
Ref: library/ssl ssl TLSVersion SSLv311172239
Ref: 36b611172239
Ref: library/ssl ssl TLSVersion TLSv111172272
Ref: 36b711172272
Ref: library/ssl ssl TLSVersion TLSv1_111172305
Ref: 36b811172305
Ref: library/ssl ssl TLSVersion TLSv1_211172340
Ref: 36b911172340
Ref: library/ssl ssl TLSVersion TLSv1_311172375
Ref: 36ba11172375
Ref: Constants<9>-Footnote-111172639
Ref: Constants<9>-Footnote-211172698
Ref: Constants<9>-Footnote-311172757
Ref: Constants<9>-Footnote-411172835
Ref: Constants<9>-Footnote-511172894
Node: SSL sockets11172987
Ref: library/ssl ssl-sockets11173141
Ref: 36bb11173141
Ref: library/ssl ssl SSLSocket11173184
Ref: 8f311173184
Ref: library/ssl ssl SSLSocket read11175604
Ref: ea211175604
Ref: library/ssl ssl SSLSocket write11176411
Ref: ea311176411
Ref: library/ssl ssl SSLSocket do_handshake11177632
Ref: ea111177632
Ref: library/ssl ssl SSLSocket getpeercert11178565
Ref: ff111178565
Ref: library/ssl ssl SSLSocket get_verified_chain11182090
Ref: 16e411182090
Ref: library/ssl ssl SSLSocket get_unverified_chain11182399
Ref: 16e511182399
Ref: library/ssl ssl SSLSocket cipher11182593
Ref: 35aa11182593
Ref: library/ssl ssl SSLSocket shared_ciphers11182877
Ref: ea011182877
Ref: library/ssl ssl SSLSocket compression11183350
Ref: 118911183350
Ref: library/ssl ssl SSLSocket get_channel_binding11183698
Ref: 118811183698
Ref: library/ssl ssl SSLSocket selected_alpn_protocol11184333
Ref: e9911184333
Ref: library/ssl ssl SSLSocket selected_npn_protocol11184746
Ref: 87b11184746
Ref: library/ssl ssl SSLSocket unwrap11185171
Ref: 36bc11185171
Ref: library/ssl ssl SSLSocket verify_client_post_handshake11185594
Ref: a3f11185594
Ref: library/ssl ssl SSLSocket version11186475
Ref: e9c11186475
Ref: library/ssl ssl SSLSocket pending11186888
Ref: 36be11186888
Ref: library/ssl ssl SSLSocket context11187026
Ref: 36bd11187026
Ref: library/ssl ssl SSLSocket server_side11187156
Ref: 36bf11187156
Ref: library/ssl ssl SSLSocket server_hostname11187328
Ref: b9d11187328
Ref: library/ssl ssl SSLSocket session11187833
Ref: 16b111187833
Ref: library/ssl ssl SSLSocket session_reused11188191
Ref: 36c011188191
Ref: SSL sockets-Footnote-111188296
Ref: SSL sockets-Footnote-211188355
Node: SSL contexts11188414
Ref: library/ssl ssl-contexts11188546
Ref: 36c111188546
Ref: library/ssl ssl SSLContext11188892
Ref: 29411188892
Ref: library/ssl ssl SSLContext cert_store_stats11193835
Ref: fe511193835
Ref: library/ssl ssl SSLContext load_cert_chain11194241
Ref: 29511194241
Ref: library/ssl ssl SSLContext load_default_certs11195865
Ref: feb11195865
Ref: library/ssl ssl SSLContext load_verify_locations11196689
Ref: f2211196689
Ref: library/ssl ssl SSLContext get_ca_certs11198019
Ref: fe611198019
Ref: library/ssl ssl SSLContext get_ciphers11198656
Ref: d0511198656
Ref: library/ssl ssl SSLContext set_default_verify_paths11199959
Ref: fe411199959
Ref: library/ssl ssl SSLContext set_ciphers11200428
Ref: 36c311200428
Ref: library/ssl ssl SSLContext set_alpn_protocols11201015
Ref: e9811201015
Ref: library/ssl ssl SSLContext set_npn_protocols11201658
Ref: 30211201658
Ref: library/ssl ssl SSLContext sni_callback11202401
Ref: 1a3511202401
Ref: library/ssl ssl SSLContext set_servername_callback11205035
Ref: ff011205035
Ref: library/ssl ssl SSLContext load_dh_params11205709
Ref: 118611205709
Ref: library/ssl ssl SSLContext set_ecdh_curve11206257
Ref: 118711206257
Ref: library/ssl ssl SSLContext wrap_socket11206989
Ref: 52811206989
Ref: library/ssl ssl SSLContext sslsocket_class11209882
Ref: 36c411209882
Ref: library/ssl ssl SSLContext wrap_bio11210194
Ref: ba011210194
Ref: library/ssl ssl SSLContext sslobject_class11210933
Ref: 36c511210933
Ref: library/ssl ssl SSLContext session_stats11211218
Ref: 36c611211218
Ref: library/ssl ssl SSLContext check_hostname11211683
Ref: 369411211683
Ref: library/ssl ssl SSLContext keylog_filename11213182
Ref: 368211213182
Ref: library/ssl ssl SSLContext maximum_version11213628
Ref: 87811213628
Ref: library/ssl ssl SSLContext minimum_version11214469
Ref: 87711214469
Ref: library/ssl ssl SSLContext num_tickets11214682
Ref: 36c711214682
Ref: library/ssl ssl SSLContext options11214915
Ref: 83e11214915
Ref: library/ssl ssl SSLContext post_handshake_auth11215640
Ref: a3e11215640
Ref: library/ssl ssl SSLContext protocol11216457
Ref: 36c811216457
Ref: library/ssl ssl SSLContext hostname_checks_common_name11216593
Ref: b9b11216593
Ref: library/ssl ssl SSLContext security_level11217028
Ref: 36c911217028
Ref: library/ssl ssl SSLContext verify_flags11217203
Ref: fe711217203
Ref: library/ssl ssl SSLContext verify_mode11217733
Ref: 368011217733
Ref: library/ssl ssl SSLContext set_psk_client_callback11218196
Ref: 36ca11218196
Ref: library/ssl ssl SSLContext set_psk_server_callback11220197
Ref: 36cb11220197
Ref: SSL contexts-Footnote-111222081
Ref: SSL contexts-Footnote-211222235
Ref: SSL contexts-Footnote-311222316
Ref: SSL contexts-Footnote-411222397
Ref: SSL contexts-Footnote-511222551
Ref: SSL contexts-Footnote-611222632
Ref: SSL contexts-Footnote-711222713
Ref: SSL contexts-Footnote-811222790
Ref: SSL contexts-Footnote-911222844
Ref: SSL contexts-Footnote-1011222903
Ref: SSL contexts-Footnote-1111222982
Ref: SSL contexts-Footnote-1211223042
Ref: SSL contexts-Footnote-1311223119
Ref: SSL contexts-Footnote-1411223185
Node: Certificates11223259
Ref: library/ssl certificates11223392
Ref: 36cc11223392
Ref: library/ssl ssl-certificates11223392
Ref: 36c211223392
Ref: Certificates-Footnote-111225741
Node: Certificate chains11225800
Ref: library/ssl certificate-chains11225891
Ref: 36cd11225891
Node: CA certificates11227162
Ref: library/ssl ca-certificates11227290
Ref: 36ce11227290
Node: Combined key and certificate11227880
Ref: library/ssl combined-key-and-certificate11228014
Ref: 36cf11228014
Node: Self-signed certificates11228630
Ref: library/ssl self-signed-certificates11228740
Ref: 36d011228740
Node: Examples<20>11230438
Ref: library/ssl examples11230588
Ref: 36d111230588
Node: Testing for SSL support11230717
Ref: library/ssl testing-for-ssl-support11230819
Ref: 36d211230819
Node: Client-side operation11231133
Ref: library/ssl client-side-operation11231265
Ref: 36d311231265
Node: Server-side operation11236006
Ref: library/ssl server-side-operation11236106
Ref: 36d411236106
Node: Notes on non-blocking sockets11238115
Ref: library/ssl notes-on-non-blocking-sockets11238271
Ref: 36d511238271
Ref: library/ssl ssl-nonblocking11238271
Ref: 368611238271
Node: Memory BIO support11241159
Ref: library/ssl memory-bio-support11241314
Ref: 36d611241314
Ref: library/ssl ssl SSLObject11242432
Ref: b9f11242432
Ref: library/ssl ssl MemoryBIO11246056
Ref: e9611246056
Ref: library/ssl ssl MemoryBIO pending11246184
Ref: 36d711246184
Ref: library/ssl ssl MemoryBIO eof11246283
Ref: 36d811246283
Ref: library/ssl ssl MemoryBIO read11246413
Ref: 36d911246413
Ref: library/ssl ssl MemoryBIO write11246574
Ref: 36da11246574
Ref: library/ssl ssl MemoryBIO write_eof11246859
Ref: 36db11246859
Node: SSL session11247151
Ref: library/ssl ssl-session11247303
Ref: 36dc11247303
Ref: library/ssl ssl SSLSession11247371
Ref: d0411247371
Ref: library/ssl ssl SSLSession id11247448
Ref: 36dd11247448
Ref: library/ssl ssl SSLSession time11247472
Ref: 36de11247472
Ref: library/ssl ssl SSLSession timeout11247498
Ref: 36df11247498
Ref: library/ssl ssl SSLSession ticket_lifetime_hint11247527
Ref: 36e011247527
Ref: library/ssl ssl SSLSession has_ticket11247569
Ref: 36e111247569
Node: Security considerations<2>11247601
Ref: library/ssl security-considerations11247742
Ref: 36e211247742
Ref: library/ssl ssl-security11247742
Ref: 356411247742
Node: Best defaults11247880
Ref: library/ssl best-defaults11247980
Ref: 36e311247980
Node: Manual settings11249141
Ref: library/ssl manual-settings11249266
Ref: 36e411249266
Node: Verifying certificates11249399
Ref: library/ssl verifying-certificates11249499
Ref: 36e511249499
Node: Protocol versions11250692
Ref: library/ssl protocol-versions11250817
Ref: 36e611250817
Node: Cipher selection11251641
Ref: library/ssl cipher-selection11251735
Ref: 36e711251735
Ref: Cipher selection-Footnote-111252391
Node: Multi-processing11252463
Ref: library/ssl multi-processing11252566
Ref: 36e811252566
Node: TLS 1 311253089
Ref: library/ssl ssl-tlsv1-311253210
Ref: b9e11253210
Ref: library/ssl tls-1-311253210
Ref: 36e911253210
Ref: TLS 1 3-Footnote-111255376
Ref: TLS 1 3-Footnote-211255442
Ref: TLS 1 3-Footnote-311255501
Ref: TLS 1 3-Footnote-411255560
Ref: TLS 1 3-Footnote-511255619
Ref: TLS 1 3-Footnote-611255678
Ref: TLS 1 3-Footnote-711255737
Ref: TLS 1 3-Footnote-811255813
Ref: TLS 1 3-Footnote-911255872
Node: select — Waiting for I/O completion11255930
Ref: library/select doc11256146
Ref: 36ea11256146
Ref: library/select module-select11256146
Ref: c111256146
Ref: library/select select-waiting-for-i-o-completion11256146
Ref: 36eb11256146
Ref: library/select translation-repo11256146
Ref: 36ec11256146
Ref: library/select select error11257307
Ref: 109411257307
Ref: library/select select devpoll11257494
Ref: fcf11257494
Ref: library/select select epoll11258216
Ref: fcd11258216
Ref: library/select select poll11259702
Ref: 2da711259702
Ref: library/select select kqueue11260021
Ref: 17dd11260021
Ref: library/select select kevent11260360
Ref: 36f111260360
Ref: library/select select select11260637
Ref: dce11260637
Ref: library/select select PIPE_BUF11262925
Ref: 124f11262925
Ref: select — Waiting for I/O completion-Footnote-111263611
Ref: select — Waiting for I/O completion-Footnote-211263653
Node: /dev/poll Polling Objects11263695
Ref: library/select dev-poll-polling-objects11263847
Ref: 36f311263847
Ref: library/select devpoll-objects11263847
Ref: 36ed11263847
Ref: library/select select devpoll close11264213
Ref: fd111264213
Ref: library/select select devpoll closed11264326
Ref: fd211264326
Ref: library/select select devpoll fileno11264435
Ref: fd011264435
Ref: library/select select devpoll register11264557
Ref: 36f411264557
Ref: library/select select devpoll modify11265539
Ref: 36f511265539
Ref: library/select select devpoll unregister11265747
Ref: 36f611265747
Ref: library/select select devpoll poll11266104
Ref: dca11266104
Ref: /dev/poll Polling Objects-Footnote-111267247
Node: Edge and Level Trigger Polling epoll Objects11267289
Ref: library/select edge-and-level-trigger-polling-epoll-objects11267465
Ref: 36f711267465
Ref: library/select epoll-objects11267465
Ref: 36ee11267465
Ref: library/select select epoll close11270335
Ref: fce11270335
Ref: library/select select epoll closed11270424
Ref: 36f811270424
Ref: library/select select epoll fileno11270501
Ref: 36f911270501
Ref: library/select select epoll fromfd11270589
Ref: 36fa11270589
Ref: library/select select epoll register11270679
Ref: 36fb11270679
Ref: library/select select epoll modify11270779
Ref: 36fc11270779
Ref: library/select select epoll unregister11270864
Ref: 96411270864
Ref: library/select select epoll poll11271057
Ref: dcb11271057
Ref: Edge and Level Trigger Polling epoll Objects-Footnote-111271459
Node: Polling Objects11271501
Ref: library/select poll-objects11271666
Ref: 36ef11271666
Ref: library/select polling-objects11271666
Ref: 36fd11271666
Ref: library/select select poll register11272241
Ref: 36fe11272241
Ref: library/select select poll modify11274218
Ref: 36ff11274218
Ref: library/select select poll unregister11274519
Ref: 370011274519
Ref: library/select select poll poll11274908
Ref: dcd11274908
Ref: Polling Objects-Footnote-111276054
Node: Kqueue Objects11276096
Ref: library/select id111276231
Ref: 370111276231
Ref: library/select kqueue-objects11276231
Ref: 36f011276231
Ref: library/select select kqueue close11276280
Ref: 370211276280
Ref: library/select select kqueue closed11276371
Ref: 370311276371
Ref: library/select select kqueue fileno11276450
Ref: 370411276450
Ref: library/select select kqueue fromfd11276539
Ref: 370511276539
Ref: library/select select kqueue control11276630
Ref: dcc11276630
Ref: Kqueue Objects-Footnote-111277281
Node: Kevent Objects11277323
Ref: library/select id211277434
Ref: 370611277434
Ref: library/select kevent-objects11277434
Ref: 36f211277434
Ref: library/select select kevent ident11277549
Ref: 370711277549
Ref: library/select select kevent filter11277851
Ref: 370811277851
Ref: library/select select kevent flags11279630
Ref: 370911279630
Ref: library/select select kevent fflags11281292
Ref: 370a11281292
Ref: library/select select kevent data11285034
Ref: 370b11285034
Ref: library/select select kevent udata11285090
Ref: 370c11285090
Node: selectors — High-level I/O multiplexing11285145
Ref: library/selectors doc11285366
Ref: 370d11285366
Ref: library/selectors module-selectors11285366
Ref: c211285366
Ref: library/selectors selectors-high-level-i-o-multiplexing11285366
Ref: 370e11285366
Ref: library/selectors translation-repo11285366
Ref: 370f11285366
Ref: selectors — High-level I/O multiplexing-Footnote-111285727
Node: Introduction<10>11285796
Ref: library/selectors introduction11285909
Ref: 371011285909
Node: Classes<4>11287248
Ref: library/selectors classes11287382
Ref: 371311287382
Ref: library/selectors selectors EVENT_READ11287962
Ref: 371411287962
Ref: library/selectors selectors EVENT_WRITE11288051
Ref: 371511288051
Ref: library/selectors selectors SelectorKey11288128
Ref: 371611288128
Ref: library/selectors selectors SelectorKey fileobj11288399
Ref: 371711288399
Ref: library/selectors selectors SelectorKey fd11288463
Ref: 371811288463
Ref: library/selectors selectors SelectorKey events11288526
Ref: 371911288526
Ref: library/selectors selectors SelectorKey data11288617
Ref: 371a11288617
Ref: library/selectors selectors BaseSelector11288783
Ref: 371111288783
Ref: library/selectors selectors BaseSelector register11289445
Ref: 371b11289445
Ref: library/selectors selectors BaseSelector unregister11290099
Ref: 371c11290099
Ref: library/selectors selectors BaseSelector modify11290719
Ref: bf511290719
Ref: library/selectors selectors BaseSelector select11291315
Ref: 371d11291315
Ref: library/selectors selectors BaseSelector close11292614
Ref: 371e11292614
Ref: library/selectors selectors BaseSelector get_key11292832
Ref: 371f11292832
Ref: library/selectors selectors BaseSelector get_map11293119
Ref: 372011293119
Ref: library/selectors selectors DefaultSelector11293387
Ref: 371211293387
Ref: library/selectors selectors SelectSelector11293595
Ref: 35ef11293595
Ref: library/selectors selectors PollSelector11293682
Ref: bf711293682
Ref: library/selectors selectors EpollSelector11293766
Ref: bf611293766
Ref: library/selectors selectors EpollSelector fileno11293851
Ref: 372111293851
Ref: library/selectors selectors DevpollSelector11293991
Ref: bf811293991
Ref: library/selectors selectors DevpollSelector fileno11294080
Ref: 372211294080
Ref: library/selectors selectors KqueueSelector11294250
Ref: 35f211294250
Ref: library/selectors selectors KqueueSelector fileno11294338
Ref: 372311294338
Ref: Classes<4>-Footnote-111294516
Node: Examples<21>11294558
Ref: library/selectors examples11294667
Ref: 372411294667
Node: signal — Set handlers for asynchronous events11295694
Ref: library/signal doc11295913
Ref: 372511295913
Ref: library/signal module-signal11295913
Ref: c611295913
Ref: library/signal signal-set-handlers-for-asynchronous-events11295913
Ref: 372611295913
Ref: library/signal translation-repo11295913
Ref: 372711295913
Ref: signal — Set handlers for asynchronous events-Footnote-111296390
Node: General rules11296456
Ref: library/signal general-rules11296580
Ref: 372811296580
Node: Execution of Python signal handlers11297547
Ref: library/signal execution-of-python-signal-handlers11297660
Ref: 372a11297660
Node: Signals and threads11298984
Ref: library/signal id111299097
Ref: 372c11299097
Ref: library/signal signals-and-threads11299097
Ref: 372d11299097
Node: Module contents<3>11299744
Ref: library/signal module-contents11299889
Ref: 372e11299889
Ref: library/signal signal Signals11300490
Ref: 373211300490
Ref: library/signal signal Handlers11300636
Ref: 373311300636
Ref: library/signal signal Sigmasks11300802
Ref: 373411300802
Ref: library/signal signal SIG_DFL11301207
Ref: 195711301207
Ref: library/signal signal SIG_IGN11301546
Ref: 195611301546
Ref: library/signal signal SIGABRT11301667
Ref: 10c011301667
Ref: library/signal signal SIGALRM11301736
Ref: 373611301736
Ref: library/signal signal SIGBREAK11301844
Ref: 373711301844
Ref: library/signal signal SIGBUS11301959
Ref: 10c111301959
Ref: library/signal signal SIGCHLD11302060
Ref: 2de311302060
Ref: library/signal signal SIGCLD11302168
Ref: 373811302168
Ref: library/signal signal SIGCONT11302273
Ref: 2df111302273
Ref: library/signal signal SIGFPE11302392
Ref: 10bf11302392
Ref: library/signal signal SIGHUP11302629
Ref: 373911302629
Ref: library/signal signal SIGILL11302777
Ref: 10c211302777
Ref: library/signal signal SIGINT11302829
Ref: 84a11302829
Ref: library/signal signal SIGKILL11302959
Ref: b7411302959
Ref: library/signal signal SIGPIPE11303091
Ref: 372911303091
Ref: library/signal signal SIGPROF11303252
Ref: 373a11303252
Ref: library/signal signal SIGQUIT11303348
Ref: 373511303348
Ref: library/signal signal SIGSEGV11303441
Ref: 10be11303441
Ref: library/signal signal SIGSTOP11303519
Ref: 373b11303519
Ref: library/signal signal SIGSTKFLT11303636
Ref: 19ab11303636
Ref: library/signal signal SIGTERM11303976
Ref: 142d11303976
Ref: library/signal signal SIGUSR111304028
Ref: 373c11304028
Ref: library/signal signal SIGUSR211304122
Ref: 373d11304122
Ref: library/signal signal SIGVTALRM11304216
Ref: 373e11304216
Ref: library/signal signal SIGWINCH11304312
Ref: 373f11304312
Ref: library/signal signal SIGXCPU11304406
Ref: 374011304406
Ref: library/signal signal CTRL_C_EVENT11305069
Ref: 13b511305069
Ref: library/signal signal CTRL_BREAK_EVENT11305307
Ref: 13b611305307
Ref: library/signal signal NSIG11305552
Ref: 193111305552
Ref: library/signal signal ITIMER_REAL11305704
Ref: 374211305704
Ref: library/signal signal ITIMER_VIRTUAL11305836
Ref: 374311305836
Ref: library/signal signal ITIMER_PROF11305982
Ref: 374411305982
Ref: library/signal signal SIG_BLOCK11306321
Ref: 372f11306321
Ref: library/signal signal SIG_UNBLOCK11306506
Ref: 373011306506
Ref: library/signal signal SIG_SETMASK11306700
Ref: 373111306700
Ref: library/signal signal ItimerError11306948
Ref: 374511306948
Ref: library/signal signal alarm11307458
Ref: 374811307458
Ref: library/signal signal getsignal11308105
Ref: 17bd11308105
Ref: library/signal signal strsignal11308663
Ref: 1bce11308663
Ref: library/signal signal valid_signals11308969
Ref: 374111308969
Ref: library/signal signal pause11309214
Ref: 374911309214
Ref: library/signal signal raise_signal11309606
Ref: 193511309606
Ref: library/signal signal pidfd_send_signal11309741
Ref: 93511309741
Ref: library/signal signal pthread_kill11310302
Ref: 117511310302
Ref: library/signal signal pthread_sigmask11311535
Ref: 117411311535
Ref: library/signal signal setitimer11312977
Ref: 374611312977
Ref: library/signal signal getitimer11314008
Ref: 374711314008
Ref: library/signal signal set_wakeup_fd11314168
Ref: b8c11314168
Ref: library/signal signal siginterrupt11316556
Ref: 117911316556
Ref: library/signal signal signal11317164
Ref: 117811317164
Ref: library/signal signal sigpending11318665
Ref: 117611318665
Ref: library/signal signal sigwait11319132
Ref: 117711319132
Ref: library/signal signal sigwaitinfo11319718
Ref: dd911319718
Ref: library/signal signal sigtimedwait11320990
Ref: dd811320990
Ref: Module contents<3>-Footnote-111321767
Ref: Module contents<3>-Footnote-211321818
Ref: Module contents<3>-Footnote-311321873
Ref: Module contents<3>-Footnote-411321918
Ref: Module contents<3>-Footnote-511321963
Ref: Module contents<3>-Footnote-611322009
Ref: Module contents<3>-Footnote-711322055
Ref: Module contents<3>-Footnote-811322101
Ref: Module contents<3>-Footnote-911322146
Ref: Module contents<3>-Footnote-1011322192
Ref: Module contents<3>-Footnote-1111322250
Ref: Module contents<3>-Footnote-1211322303
Ref: Module contents<3>-Footnote-1311322355
Ref: Module contents<3>-Footnote-1411322411
Ref: Module contents<3>-Footnote-1511322464
Ref: Module contents<3>-Footnote-1611322511
Ref: Module contents<3>-Footnote-1711322562
Ref: Module contents<3>-Footnote-1811322610
Ref: Module contents<3>-Footnote-1911322662
Ref: Module contents<3>-Footnote-2011322705
Ref: Module contents<3>-Footnote-2111322758
Node: Examples<22>11322801
Ref: library/signal examples11322948
Ref: 374a11322948
Ref: library/signal signal-example11322948
Ref: 374b11322948
Node: Note on SIGPIPE11323910
Ref: library/signal note-on-sigpipe11324077
Ref: 374c11324077
Ref: Note on SIGPIPE-Footnote-111325526
Node: Note on Signal Handlers and Exceptions11325570
Ref: library/signal handlers-and-exceptions11325716
Ref: 244411325716
Ref: library/signal note-on-signal-handlers-and-exceptions11325716
Ref: 374d11325716
Node: mmap — Memory-mapped file support11328307
Ref: library/mmap doc11328476
Ref: 374e11328476
Ref: library/mmap mmap-memory-mapped-file-support11328476
Ref: 374f11328476
Ref: library/mmap module-mmap11328476
Ref: 9011328476
Ref: library/mmap translation-repo11328476
Ref: 375011328476
Ref: library/mmap mmap mmap11331077
Ref: 20b11331077
Ref: library/mmap mmap mmap close11336677
Ref: 375611336677
Ref: library/mmap mmap mmap closed11336888
Ref: 375711336888
Ref: library/mmap mmap mmap find11336994
Ref: 375811336994
Ref: library/mmap mmap mmap flush11337424
Ref: aad11337424
Ref: library/mmap mmap mmap madvise11338338
Ref: a1311338338
Ref: library/mmap mmap mmap move11338906
Ref: 375a11338906
Ref: library/mmap mmap mmap read11339184
Ref: 112111339184
Ref: library/mmap mmap mmap read_byte11339636
Ref: 375b11339636
Ref: library/mmap mmap mmap readline11339784
Ref: 375c11339784
Ref: library/mmap mmap mmap resize11340009
Ref: 375511340009
Ref: library/mmap mmap mmap rfind11340868
Ref: 375d11340868
Ref: library/mmap mmap mmap seek11341300
Ref: 20d11341300
Ref: library/mmap mmap mmap seekable11341788
Ref: 20c11341788
Ref: library/mmap mmap mmap size11341958
Ref: 375411341958
Ref: library/mmap mmap mmap tell11342097
Ref: 375e11342097
Ref: library/mmap mmap mmap write11342184
Ref: d7311342184
Ref: library/mmap mmap mmap write_byte11342891
Ref: 375f11342891
Node: MADV_* Constants11343257
Ref: library/mmap madv-constants11343369
Ref: 376011343369
Ref: library/mmap madvise-constants11343369
Ref: 375911343369
Ref: library/mmap mmap MADV_NORMAL11343422
Ref: 376111343422
Ref: library/mmap mmap MADV_RANDOM11343449
Ref: 376211343449
Ref: library/mmap mmap MADV_SEQUENTIAL11343476
Ref: 376311343476
Ref: library/mmap mmap MADV_WILLNEED11343507
Ref: 376411343507
Ref: library/mmap mmap MADV_DONTNEED11343536
Ref: 376511343536
Ref: library/mmap mmap MADV_REMOVE11343565
Ref: 376611343565
Ref: library/mmap mmap MADV_DONTFORK11343592
Ref: 376711343592
Ref: library/mmap mmap MADV_DOFORK11343621
Ref: 376811343621
Ref: library/mmap mmap MADV_HWPOISON11343648
Ref: 376911343648
Ref: library/mmap mmap MADV_MERGEABLE11343677
Ref: 376a11343677
Ref: library/mmap mmap MADV_UNMERGEABLE11343707
Ref: 376b11343707
Ref: library/mmap mmap MADV_SOFT_OFFLINE11343739
Ref: 376c11343739
Ref: library/mmap mmap MADV_HUGEPAGE11343772
Ref: 376d11343772
Ref: library/mmap mmap MADV_NOHUGEPAGE11343801
Ref: 376e11343801
Ref: library/mmap mmap MADV_DONTDUMP11343832
Ref: 376f11343832
Ref: library/mmap mmap MADV_DODUMP11343861
Ref: 377011343861
Ref: library/mmap mmap MADV_FREE11343888
Ref: 377111343888
Ref: library/mmap mmap MADV_NOSYNC11343913
Ref: 377211343913
Ref: library/mmap mmap MADV_AUTOSYNC11343940
Ref: 377311343940
Ref: library/mmap mmap MADV_NOCORE11343969
Ref: 377411343969
Ref: library/mmap mmap MADV_CORE11343996
Ref: 377511343996
Ref: library/mmap mmap MADV_PROTECT11344021
Ref: 377611344021
Ref: library/mmap mmap MADV_FREE_REUSABLE11344049
Ref: 377711344049
Ref: library/mmap mmap MADV_FREE_REUSE11344083
Ref: 377811344083
Node: MAP_* Constants11344323
Ref: library/mmap id111344435
Ref: 377911344435
Ref: library/mmap map-constants11344435
Ref: 375311344435
Ref: library/mmap mmap MAP_SHARED11344486
Ref: 375211344486
Ref: library/mmap mmap MAP_PRIVATE11344512
Ref: 375111344512
Ref: library/mmap mmap MAP_32BIT11344539
Ref: 17b411344539
Ref: library/mmap mmap MAP_ALIGNED_SUPER11344564
Ref: 186a11344564
Ref: library/mmap mmap MAP_ANON11344597
Ref: 377a11344597
Ref: library/mmap mmap MAP_ANONYMOUS11344621
Ref: 377b11344621
Ref: library/mmap mmap MAP_CONCEAL11344650
Ref: 186b11344650
Ref: library/mmap mmap MAP_DENYWRITE11344677
Ref: 377c11344677
Ref: library/mmap mmap MAP_EXECUTABLE11344706
Ref: 377d11344706
Ref: library/mmap mmap MAP_HASSEMAPHORE11344736
Ref: 17af11344736
Ref: library/mmap mmap MAP_JIT11344768
Ref: 17b111344768
Ref: library/mmap mmap MAP_NOCACHE11344791
Ref: 17b011344791
Ref: library/mmap mmap MAP_NOEXTEND11344818
Ref: 17ae11344818
Ref: library/mmap mmap MAP_NORESERVE11344846
Ref: 17ad11344846
Ref: library/mmap mmap MAP_POPULATE11344875
Ref: 1ad611344875
Ref: library/mmap mmap MAP_RESILIENT_CODESIGN11344903
Ref: 17b211344903
Ref: library/mmap mmap MAP_RESILIENT_MEDIA11344941
Ref: 17b311344941
Ref: library/mmap mmap MAP_STACK11344976
Ref: 377e11344976
Ref: library/mmap mmap MAP_TPRO11345001
Ref: 17b711345001
Ref: library/mmap mmap MAP_TRANSLATED_ALLOW_EXECUTE11345025
Ref: 17b511345025
Ref: library/mmap mmap MAP_UNIX0311345069
Ref: 17b611345069
Node: Internet Data Handling11345889
Ref: library/netdata doc11346068
Ref: 377f11346068
Ref: library/netdata internet-data-handling11346068
Ref: 378011346068
Ref: library/netdata netdata11346068
Ref: 378111346068
Ref: library/netdata translation-repo11346068
Ref: 378211346068
Node: email — An email and MIME handling package11346648
Ref: library/email doc11346793
Ref: 378311346793
Ref: library/email email-an-email-and-mime-handling-package11346793
Ref: 378411346793
Ref: library/email module-email11346793
Ref: 3b11346793
Ref: email — An email and MIME handling package-Footnote-111353475
Ref: email — An email and MIME handling package-Footnote-211353549
Ref: email — An email and MIME handling package-Footnote-311353608
Ref: email — An email and MIME handling package-Footnote-411353667
Ref: email — An email and MIME handling package-Footnote-511353726
Ref: email — An email and MIME handling package-Footnote-611353785
Ref: email — An email and MIME handling package-Footnote-711353844
Ref: email — An email and MIME handling package-Footnote-811353903
Ref: email — An email and MIME handling package-Footnote-911353962
Node: email message Representing an email message11354021
Ref: library/email message doc11354189
Ref: 378511354189
Ref: library/email message email-message-representing-an-email-message11354189
Ref: 378611354189
Ref: library/email message module-email message11354189
Ref: 4411354189
Ref: library/email message email message EmailMessage11356647
Ref: 27b11356647
Ref: library/email message email message EmailMessage as_string11357133
Ref: 378811357133
Ref: library/email message email message EmailMessage __str__11358980
Ref: 378a11358980
Ref: library/email message email message EmailMessage as_bytes11359449
Ref: 378b11359449
Ref: library/email message email message EmailMessage __bytes__11360607
Ref: 378c11360607
Ref: library/email message email message EmailMessage is_multipart11360783
Ref: 378d11360783
Ref: library/email message email message EmailMessage set_unixfrom11361441
Ref: 378e11361441
Ref: library/email message email message EmailMessage get_unixfrom11361663
Ref: 379011361663
Ref: library/email message email message EmailMessage __len__11362788
Ref: 379211362788
Ref: library/email message email message EmailMessage __contains__11362886
Ref: 379311362886
Ref: library/email message email message EmailMessage __getitem__11363276
Ref: 379411363276
Ref: library/email message email message EmailMessage __setitem__11363993
Ref: 379711363993
Ref: library/email message email message EmailMessage __delitem__11365031
Ref: 379811365031
Ref: library/email message email message EmailMessage keys11365257
Ref: 379111365257
Ref: library/email message email message EmailMessage values11365351
Ref: 379911365351
Ref: library/email message email message EmailMessage items11365441
Ref: 379a11365441
Ref: library/email message email message EmailMessage get11365572
Ref: 379b11365572
Ref: library/email message email message EmailMessage get_all11365920
Ref: 379511365920
Ref: library/email message email message EmailMessage add_header11366157
Ref: 379c11366157
Ref: library/email message email message EmailMessage replace_header11368121
Ref: 379d11368121
Ref: library/email message email message EmailMessage get_content_type11368427
Ref: 379e11368427
Ref: library/email message email message EmailMessage get_content_maintype11369305
Ref: 37a011369305
Ref: library/email message email message EmailMessage get_content_subtype11369511
Ref: 37a111369511
Ref: library/email message email message EmailMessage get_default_type11369704
Ref: 379f11369704
Ref: library/email message email message EmailMessage set_default_type11370024
Ref: 37a211370024
Ref: library/email message email message EmailMessage set_param11370466
Ref: 37a311370466
Ref: library/email message email message EmailMessage del_param11372081
Ref: 37a511372081
Ref: library/email message email message EmailMessage get_filename11372511
Ref: 37a611372511
Ref: library/email message email message EmailMessage get_boundary11373050
Ref: 37a811373050
Ref: library/email message email message EmailMessage set_boundary11373414
Ref: 37a911373414
Ref: library/email message email message EmailMessage get_content_charset11374068
Ref: 37ab11374068
Ref: library/email message email message EmailMessage get_charsets11374370
Ref: 37ac11374370
Ref: library/email message email message EmailMessage is_attachment11375063
Ref: 37ad11375063
Ref: library/email message email message EmailMessage get_content_disposition11375430
Ref: 37af11375430
Ref: library/email message email message EmailMessage walk11375907
Ref: 37b011375907
Ref: library/email message email message EmailMessage get_body11377906
Ref: 37b111377906
Ref: library/email message email message EmailMessage iter_attachments11380025
Ref: 37b211380025
Ref: library/email message email message EmailMessage iter_parts11380999
Ref: 37b311380999
Ref: library/email message email message EmailMessage get_content11381212
Ref: 37b411381212
Ref: library/email message email message EmailMessage set_content11381622
Ref: 1a0311381622
Ref: library/email message email message EmailMessage make_related11382032
Ref: 37b711382032
Ref: library/email message email message EmailMessage make_alternative11382520
Ref: 37b811382520
Ref: library/email message email message EmailMessage make_mixed11383039
Ref: 37b911383039
Ref: library/email message email message EmailMessage add_related11383578
Ref: 37ba11383578
Ref: library/email message email message EmailMessage add_alternative11384335
Ref: 37bc11384335
Ref: library/email message email message EmailMessage add_attachment11385025
Ref: 37bd11385025
Ref: library/email message email message EmailMessage clear11386010
Ref: 37be11386010
Ref: library/email message email message EmailMessage clear_content11386091
Ref: 37bf11386091
Ref: library/email message email message EmailMessage preamble11386341
Ref: 37c011386341
Ref: library/email message email message EmailMessage epilogue11387605
Ref: 37c111387605
Ref: library/email message email message EmailMessage defects11387951
Ref: 37c211387951
Ref: library/email message email message MIMEPart11388193
Ref: f7211388193
Ref: email message Representing an email message-Footnote-111388559
Ref: email message Representing an email message-Footnote-211388632
Ref: email message Representing an email message-Footnote-311388829
Ref: email message Representing an email message-Footnote-411388888
Ref: email message Representing an email message-Footnote-511388947
Ref: email message Representing an email message-Footnote-611389006
Ref: email message Representing an email message-Footnote-711389323
Ref: email message Representing an email message-Footnote-811389382
Ref: email message Representing an email message-Footnote-911389441
Ref: email message Representing an email message-Footnote-1011389500
Ref: email message Representing an email message-Footnote-1111389560
Ref: email message Representing an email message-Footnote-1211389620
Ref: email message Representing an email message-Footnote-1311389680
Ref: email message Representing an email message-Footnote-1411389740
Node: email parser Parsing email messages11389800
Ref: library/email parser doc11390018
Ref: 37c311390018
Ref: library/email parser email-parser-parsing-email-messages11390018
Ref: 37c411390018
Ref: library/email parser module-email parser11390018
Ref: 4e11390018
Ref: library/email parser translation-repo11390018
Ref: 37c511390018
Ref: email parser Parsing email messages-Footnote-111392390
Node: FeedParser API11392462
Ref: library/email parser feedparser-api11392567
Ref: 37c611392567
Ref: library/email parser email parser BytesFeedParser11393851
Ref: 121011393851
Ref: library/email parser email parser BytesFeedParser feed11395047
Ref: 37c711395047
Ref: library/email parser email parser BytesFeedParser close11395482
Ref: 37c811395482
Ref: library/email parser email parser FeedParser11395722
Ref: 15d011395722
Node: Parser API11396187
Ref: library/email parser parser-api11396317
Ref: 37c911396317
Ref: library/email parser email parser BytesParser11397026
Ref: 121111397026
Ref: library/email parser email parser BytesParser parse11397688
Ref: 37ca11397688
Ref: library/email parser email parser BytesParser parsebytes11398740
Ref: 37cb11398740
Ref: library/email parser email parser BytesHeaderParser11399230
Ref: 10ff11399230
Ref: library/email parser email parser Parser11399451
Ref: 11e111399451
Ref: library/email parser email parser Parser parse11399797
Ref: 37cc11399797
Ref: library/email parser email parser Parser parsestr11400235
Ref: 37cd11400235
Ref: library/email parser email parser HeaderParser11400658
Ref: 110011400658
Ref: library/email parser email message_from_bytes11401056
Ref: 120e11401056
Ref: library/email parser email message_from_binary_file11401526
Ref: 120f11401526
Ref: library/email parser email message_from_string11402004
Ref: 37ce11402004
Ref: library/email parser email message_from_file11402400
Ref: 37cf11402400
Ref: Parser API-Footnote-111403132
Ref: Parser API-Footnote-211403191
Node: Additional notes11403250
Ref: library/email parser additional-notes11403357
Ref: 37d011403357
Node: email generator Generating MIME documents11404911
Ref: library/email generator doc11405113
Ref: 37d211405113
Ref: library/email generator email-generator-generating-mime-documents11405113
Ref: 37d311405113
Ref: library/email generator module-email generator11405113
Ref: 4011405113
Ref: library/email generator translation-repo11405113
Ref: 37d411405113
Ref: library/email generator email generator BytesGenerator11407199
Ref: 121411407199
Ref: library/email generator email generator BytesGenerator flatten11409101
Ref: 37d611409101
Ref: library/email generator email generator BytesGenerator clone11410917
Ref: 37d911410917
Ref: library/email generator email generator BytesGenerator write11411109
Ref: 37d711411109
Ref: library/email generator email generator Generator11412135
Ref: 121311412135
Ref: library/email generator email generator Generator flatten11413975
Ref: 37da11413975
Ref: library/email generator email generator Generator clone11415729
Ref: 37dc11415729
Ref: library/email generator email generator Generator write11415898
Ref: 37db11415898
Ref: library/email generator email generator DecodedGenerator11416791
Ref: cbc11416791
Ref: email generator Generating MIME documents-Footnote-111418210
Ref: email generator Generating MIME documents-Footnote-211418286
Ref: email generator Generating MIME documents-Footnote-311418793
Ref: email generator Generating MIME documents-Footnote-411418845
Ref: email generator Generating MIME documents-Footnote-511418904
Ref: email generator Generating MIME documents-Footnote-611418956
Node: email policy Policy Objects11419015
Ref: library/email policy doc11419223
Ref: 37dd11419223
Ref: library/email policy email-policy-policy-objects11419223
Ref: 37de11419223
Ref: library/email policy module-email policy11419223
Ref: 4f11419223
Ref: library/email policy translation-repo11419223
Ref: 37df11419223
Ref: library/email policy email policy Policy11425182
Ref: 10f711425182
Ref: library/email policy email policy Policy max_line_length11426005
Ref: 378911426005
Ref: library/email policy email policy Policy linesep11426311
Ref: 37e011426311
Ref: library/email policy email policy Policy cte_type11426580
Ref: 37d811426580
Ref: library/email policy email policy Policy raise_on_defect11427691
Ref: 37e211427691
Ref: library/email policy email policy Policy mangle_from_11427935
Ref: e2811427935
Ref: library/email policy email policy Policy message_factory11428264
Ref: cbd11428264
Ref: library/email policy email policy Policy verify_generated_headers11428541
Ref: 1e011428541
Ref: library/email policy email policy Policy clone11429382
Ref: 10f911429382
Ref: library/email policy email policy Policy handle_defect11429844
Ref: 37e511429844
Ref: library/email policy email policy Policy register_defect11430336
Ref: 37e311430336
Ref: library/email policy email policy Policy header_max_count11431042
Ref: 37e711431042
Ref: library/email policy email policy Policy header_source_parse11432104
Ref: 37e811432104
Ref: library/email policy email policy Policy header_store_parse11433117
Ref: 37e911433117
Ref: library/email policy email policy Policy header_fetch_parse11433878
Ref: 37ea11433878
Ref: library/email policy email policy Policy fold11434701
Ref: 37eb11434701
Ref: library/email policy email policy Policy fold_binary11435417
Ref: 37e111435417
Ref: library/email policy email policy EmailPolicy11435751
Ref: 10fb11435751
Ref: library/email policy email policy EmailPolicy utf811436584
Ref: e2a11436584
Ref: library/email policy email policy EmailPolicy refold_source11436980
Ref: 37d511436980
Ref: library/email policy email policy EmailPolicy header_factory11437775
Ref: 37ec11437775
Ref: library/email policy email policy EmailPolicy content_manager11438386
Ref: f7311438386
Ref: library/email policy email policy EmailPolicy header_max_count11439098
Ref: 37ee11439098
Ref: library/email policy email policy EmailPolicy header_source_parse11439304
Ref: 16aa11439304
Ref: library/email policy email policy EmailPolicy header_store_parse11439689
Ref: 37f011439689
Ref: library/email policy email policy EmailPolicy header_fetch_parse11440170
Ref: 37f111440170
Ref: library/email policy email policy EmailPolicy fold11440596
Ref: 178811440596
Ref: library/email policy email policy EmailPolicy fold_binary11441759
Ref: 37f211441759
Ref: library/email policy email policy default11442579
Ref: 15d111442579
Ref: library/email policy email policy SMTP11442789
Ref: 37f311442789
Ref: library/email policy email policy SMTPUTF811442991
Ref: 37f411442991
Ref: library/email policy email policy HTTP11443405
Ref: 37f511443405
Ref: library/email policy email policy strict11443597
Ref: 37f611443597
Ref: library/email policy email policy Compat3211444975
Ref: 10f811444975
Ref: library/email policy email policy Compat32 mangle_from_11445504
Ref: 37f711445504
Ref: library/email policy email policy Compat32 header_source_parse11445693
Ref: 16ab11445693
Ref: library/email policy email policy Compat32 header_store_parse11446078
Ref: 37f811446078
Ref: library/email policy email policy Compat32 header_fetch_parse11446184
Ref: 37f911446184
Ref: library/email policy email policy Compat32 fold11446426
Ref: 37fa11446426
Ref: library/email policy email policy Compat32 fold_binary11446769
Ref: 37fb11446769
Ref: library/email policy email policy compat3211447299
Ref: cbe11447299
Ref: email policy Policy Objects-Footnote-111447748
Ref: email policy Policy Objects-Footnote-211447820
Ref: email policy Policy Objects-Footnote-311447879
Ref: email policy Policy Objects-Footnote-411447938
Ref: email policy Policy Objects-Footnote-511447997
Ref: email policy Policy Objects-Footnote-611448056
Ref: email policy Policy Objects-Footnote-711448115
Ref: email policy Policy Objects-Footnote-811448174
Ref: email policy Policy Objects-Footnote-911448244
Ref: email policy Policy Objects-Footnote-1011448303
Ref: email policy Policy Objects-Footnote-1111448363
Ref: email policy Policy Objects-Footnote-1211448423
Node: email errors Exception and Defect classes11448483
Ref: library/email errors doc11448692
Ref: 37fc11448692
Ref: library/email errors email-errors-exception-and-defect-classes11448692
Ref: 37fd11448692
Ref: library/email errors module-email errors11448692
Ref: 3f11448692
Ref: library/email errors translation-repo11448692
Ref: 37fe11448692
Ref: library/email errors email errors MessageError11448991
Ref: 37ff11448991
Ref: library/email errors email errors MessageParseError11449232
Ref: 380011449232
Ref: library/email errors email errors HeaderParseError11449509
Ref: 37aa11449509
Ref: library/email errors email errors BoundaryError11450152
Ref: 380111450152
Ref: library/email errors email errors MultipartConversionError11450232
Ref: 380211450232
Ref: library/email errors email errors HeaderWriteError11450586
Ref: 37e411450586
Ref: library/email errors email errors MessageDefect11450718
Ref: 37e611450718
Ref: library/email errors email errors HeaderDefect11450889
Ref: 380511450889
Ref: library/email errors email errors NoBoundaryInMultipartDefect11451502
Ref: 380611451502
Ref: library/email errors email errors StartBoundaryNotFoundDefect11451644
Ref: 380711451644
Ref: library/email errors email errors CloseBoundaryNotFoundDefect11451789
Ref: 380811451789
Ref: library/email errors email errors FirstHeaderLineIsContinuationDefect11451965
Ref: 380911451965
Ref: library/email errors email errors MisplacedEnvelopeHeaderDefect11452098
Ref: 380a11452098
Ref: library/email errors email errors MissingHeaderBodySeparatorDefect11452231
Ref: 380b11452231
Ref: library/email errors email errors MalformedHeaderDefect11452515
Ref: 380c11452515
Ref: library/email errors email errors MultipartInvariantViolationDefect11452750
Ref: 37d111452750
Ref: library/email errors email errors InvalidBase64PaddingDefect11453068
Ref: 380d11453068
Ref: library/email errors email errors InvalidBase64CharactersDefect11453312
Ref: 380e11453312
Ref: library/email errors email errors InvalidBase64LengthDefect11453568
Ref: 380f11453568
Ref: library/email errors email errors InvalidDateDefect11453808
Ref: 381011453808
Ref: email errors Exception and Defect classes-Footnote-111453988
Ref: email errors Exception and Defect classes-Footnote-211454060
Node: email headerregistry Custom Header Objects11454119
Ref: library/email headerregistry doc11454343
Ref: 381111454343
Ref: library/email headerregistry email-headerregistry-custom-header-objects11454343
Ref: 381211454343
Ref: library/email headerregistry module-email headerregistry11454343
Ref: 4211454343
Ref: library/email headerregistry translation-repo11454343
Ref: 381311454343
Ref: library/email headerregistry email headerregistry BaseHeader11456106
Ref: 379611456106
Ref: library/email headerregistry email headerregistry BaseHeader name11456419
Ref: 381611456419
Ref: library/email headerregistry email headerregistry BaseHeader defects11456670
Ref: 381711456670
Ref: library/email headerregistry email headerregistry BaseHeader max_count11457029
Ref: 37ef11457029
Ref: library/email headerregistry email headerregistry BaseHeader fold11457546
Ref: 381811457546
Ref: library/email headerregistry email headerregistry UnstructuredHeader11459737
Ref: 381511459737
Ref: library/email headerregistry email headerregistry DateHeader11460816
Ref: 381911460816
Ref: library/email headerregistry email headerregistry DateHeader datetime11461179
Ref: 381a11461179
Ref: library/email headerregistry email headerregistry AddressHeader11462726
Ref: 381b11462726
Ref: library/email headerregistry email headerregistry AddressHeader groups11463010
Ref: 381c11463010
Ref: library/email headerregistry email headerregistry AddressHeader addresses11463325
Ref: 381f11463325
Ref: library/email headerregistry email headerregistry SingleAddressHeader11464487
Ref: 382111464487
Ref: library/email headerregistry email headerregistry SingleAddressHeader address11464628
Ref: 382211464628
Ref: library/email headerregistry email headerregistry MIMEVersionHeader11465160
Ref: 382311465160
Ref: library/email headerregistry email headerregistry MIMEVersionHeader version11465552
Ref: 382411465552
Ref: library/email headerregistry email headerregistry MIMEVersionHeader major11465679
Ref: 382511465679
Ref: library/email headerregistry email headerregistry MIMEVersionHeader minor11465756
Ref: 382611465756
Ref: library/email headerregistry email headerregistry ParameterizedMIMEHeader11465833
Ref: 382711465833
Ref: library/email headerregistry email headerregistry ParameterizedMIMEHeader params11466216
Ref: 37a411466216
Ref: library/email headerregistry email headerregistry ContentTypeHeader11466313
Ref: 382811466313
Ref: library/email headerregistry email headerregistry ContentTypeHeader content_type11466464
Ref: 382911466464
Ref: library/email headerregistry email headerregistry ContentTypeHeader maintype11466570
Ref: 382a11466570
Ref: library/email headerregistry email headerregistry ContentTypeHeader subtype11466600
Ref: 382b11466600
Ref: library/email headerregistry email headerregistry ContentDispositionHeader11466629
Ref: 382c11466629
Ref: library/email headerregistry email headerregistry ContentDispositionHeader content_disposition11466794
Ref: 382d11466794
Ref: library/email headerregistry email headerregistry ContentTransferEncodingHeader11466931
Ref: 382e11466931
Ref: library/email headerregistry email headerregistry ContentTransferEncodingHeader cte11467052
Ref: 382f11467052
Ref: library/email headerregistry email headerregistry HeaderRegistry11467221
Ref: 381411467221
Ref: library/email headerregistry email headerregistry HeaderRegistry map_to_type11468954
Ref: 383011468954
Ref: library/email headerregistry email headerregistry HeaderRegistry __getitem__11469289
Ref: 383111469289
Ref: library/email headerregistry email headerregistry HeaderRegistry __call__11469412
Ref: 383211469412
Ref: library/email headerregistry email headerregistry Address11470054
Ref: 382011470054
Ref: library/email headerregistry email headerregistry Address display_name11470893
Ref: 383311470893
Ref: library/email headerregistry email headerregistry Address username11471119
Ref: 383411471119
Ref: library/email headerregistry email headerregistry Address domain11471239
Ref: 383511471239
Ref: library/email headerregistry email headerregistry Address addr_spec11471319
Ref: 383611471319
Ref: library/email headerregistry email headerregistry Address __str__11471537
Ref: 383711471537
Ref: library/email headerregistry email headerregistry Group11471976
Ref: 381d11471976
Ref: library/email headerregistry email headerregistry Group display_name11472525
Ref: 381e11472525
Ref: library/email headerregistry email headerregistry Group addresses11472780
Ref: 383811472780
Ref: library/email headerregistry email headerregistry Group __str__11472928
Ref: 383911472928
Ref: email headerregistry Custom Header Objects-Footnote-111473368
Ref: email headerregistry Custom Header Objects-Footnote-211473449
Ref: email headerregistry Custom Header Objects-Footnote-311473518
Ref: email headerregistry Custom Header Objects-Footnote-411473577
Ref: email headerregistry Custom Header Objects-Footnote-511473636
Ref: email headerregistry Custom Header Objects-Footnote-611473695
Ref: email headerregistry Custom Header Objects-Footnote-711473754
Ref: email headerregistry Custom Header Objects-Footnote-811473813
Ref: email headerregistry Custom Header Objects-Footnote-911473872
Ref: email headerregistry Custom Header Objects-Footnote-1011473931
Ref: email headerregistry Custom Header Objects-Footnote-1111473991
Ref: email headerregistry Custom Header Objects-Footnote-1211474051
Ref: email headerregistry Custom Header Objects-Footnote-1311474111
Ref: email headerregistry Custom Header Objects-Footnote-1411474171
Ref: email headerregistry Custom Header Objects-Footnote-1511474231
Ref: email headerregistry Custom Header Objects-Footnote-1611474291
Ref: email headerregistry Custom Header Objects-Footnote-1711474351
Node: email contentmanager Managing MIME Content11474411
Ref: library/email contentmanager doc11474608
Ref: 383a11474608
Ref: library/email contentmanager email-contentmanager-managing-mime-content11474608
Ref: 383b11474608
Ref: library/email contentmanager module-email contentmanager11474608
Ref: 3d11474608
Ref: library/email contentmanager translation-repo11474608
Ref: 383c11474608
Ref: library/email contentmanager email contentmanager ContentManager11474867
Ref: 383d11474867
Ref: library/email contentmanager email contentmanager ContentManager get_content11475156
Ref: 37b511475156
Ref: library/email contentmanager email contentmanager ContentManager set_content11475990
Ref: 37b611475990
Ref: library/email contentmanager email contentmanager ContentManager add_get_handler11477622
Ref: 383e11477622
Ref: library/email contentmanager email contentmanager ContentManager add_set_handler11477814
Ref: 384011477814
Ref: email contentmanager Managing MIME Content-Footnote-111478173
Ref: email contentmanager Managing MIME Content-Footnote-211478254
Node: Content Manager Instances11478323
Ref: library/email contentmanager content-manager-instances11478427
Ref: 384211478427
Ref: library/email contentmanager email contentmanager raw_data_manager11478761
Ref: 37ed11478761
Ref: library/email contentmanager email contentmanager get_content11479485
Ref: 383f11479485
Ref: library/email contentmanager email contentmanager set_content11480084
Ref: 384111480084
Ref: Content Manager Instances-Footnote-111484868
Node: email Examples11484927
Ref: library/email examples doc11485156
Ref: 384311485156
Ref: library/email examples email-examples11485156
Ref: f7411485156
Ref: library/email examples id111485156
Ref: 384411485156
Ref: library/email examples translation-repo11485156
Ref: 384511485156
Ref: email Examples-Footnote-111499782
Ref: email Examples-Footnote-211499840
Node: email message Message Representing an email message using the compat32 API11499922
Ref: library/email compat32-message doc11500164
Ref: 384611500164
Ref: library/email compat32-message compat32-message11500164
Ref: 378711500164
Ref: library/email compat32-message email-message-message-representing-an-email-message-using-the-compat32-api11500164
Ref: 384711500164
Ref: library/email compat32-message translation-repo11500164
Ref: 384811500164
Ref: library/email compat32-message email message Message11502710
Ref: 27c11502710
Ref: library/email compat32-message email message Message as_string11503238
Ref: f6e11503238
Ref: library/email compat32-message email message Message __str__11505382
Ref: 384911505382
Ref: library/email compat32-message email message Message as_bytes11505547
Ref: f6f11505547
Ref: library/email compat32-message email message Message __bytes__11507099
Ref: f7011507099
Ref: library/email compat32-message email message Message is_multipart11507306
Ref: 37ae11507306
Ref: library/email compat32-message email message Message set_unixfrom11507956
Ref: 384a11507956
Ref: library/email compat32-message email message Message get_unixfrom11508096
Ref: 384b11508096
Ref: library/email compat32-message email message Message attach11508253
Ref: 37bb11508253
Ref: library/email compat32-message email message Message get_payload11508855
Ref: 121211508855
Ref: library/email compat32-message email message Message set_payload11511501
Ref: 384c11511501
Ref: library/email compat32-message email message Message set_charset11511985
Ref: 384d11511985
Ref: library/email compat32-message email message Message get_charset11513756
Ref: 384e11513756
Ref: library/email compat32-message email message Message __len__11515208
Ref: 385011515208
Ref: library/email compat32-message email message Message __contains__11515306
Ref: 189711515306
Ref: library/email compat32-message email message Message __getitem__11515676
Ref: 385111515676
Ref: library/email compat32-message email message Message __setitem__11516211
Ref: 385311516211
Ref: library/email compat32-message email message Message __delitem__11516768
Ref: 385411516768
Ref: library/email compat32-message email message Message keys11516994
Ref: 384f11516994
Ref: library/email compat32-message email message Message values11517088
Ref: 385511517088
Ref: library/email compat32-message email message Message items11517178
Ref: 385611517178
Ref: library/email compat32-message email message Message get11517309
Ref: 385711517309
Ref: library/email compat32-message email message Message get_all11517622
Ref: 385211517622
Ref: library/email compat32-message email message Message add_header11517859
Ref: 385811517859
Ref: library/email compat32-message email message Message replace_header11519825
Ref: 385911519825
Ref: library/email compat32-message email message Message get_content_type11520114
Ref: 385a11520114
Ref: library/email compat32-message email message Message get_content_maintype11520965
Ref: 385c11520965
Ref: library/email compat32-message email message Message get_content_subtype11521171
Ref: 385d11521171
Ref: library/email compat32-message email message Message get_default_type11521364
Ref: 385b11521364
Ref: library/email compat32-message email message Message set_default_type11521684
Ref: 385e11521684
Ref: library/email compat32-message email message Message get_params11521971
Ref: 385f11521971
Ref: library/email compat32-message email message Message get_param11523033
Ref: 386011523033
Ref: library/email compat32-message email message Message set_param11525035
Ref: f7111525035
Ref: library/email compat32-message email message Message del_param11526302
Ref: 386211526302
Ref: library/email compat32-message email message Message set_type11526743
Ref: 386311526743
Ref: library/email compat32-message email message Message get_filename11527632
Ref: 386411527632
Ref: library/email compat32-message email message Message get_boundary11528171
Ref: 386511528171
Ref: library/email compat32-message email message Message set_boundary11528535
Ref: 386611528535
Ref: library/email compat32-message email message Message get_content_charset11529336
Ref: 386711529336
Ref: library/email compat32-message email message Message get_charsets11529824
Ref: 386811529824
Ref: library/email compat32-message email message Message get_content_disposition11530526
Ref: e2911530526
Ref: library/email compat32-message email message Message walk11530891
Ref: 386911530891
Ref: library/email compat32-message email message Message preamble11532991
Ref: 386a11532991
Ref: library/email compat32-message email message Message epilogue11534255
Ref: 386b11534255
Ref: library/email compat32-message email message Message defects11534654
Ref: 386c11534654
Ref: email message Message Representing an email message using the compat32 API-Footnote-111534932
Ref: email message Message Representing an email message using the compat32 API-Footnote-211534991
Ref: email message Message Representing an email message using the compat32 API-Footnote-311535050
Ref: email message Message Representing an email message using the compat32 API-Footnote-411535109
Ref: email message Message Representing an email message using the compat32 API-Footnote-511535168
Ref: email message Message Representing an email message using the compat32 API-Footnote-611535227
Ref: email message Message Representing an email message using the compat32 API-Footnote-711535286
Ref: email message Message Representing an email message using the compat32 API-Footnote-811535345
Ref: email message Message Representing an email message using the compat32 API-Footnote-911535404
Ref: email message Message Representing an email message using the compat32 API-Footnote-1011535463
Ref: email message Message Representing an email message using the compat32 API-Footnote-1111535523
Ref: email message Message Representing an email message using the compat32 API-Footnote-1211535583
Node: email mime Creating email and MIME objects from scratch11535643
Ref: library/email mime doc11535909
Ref: 386d11535909
Ref: library/email mime email-mime-creating-email-and-mime-objects-from-scratch11535909
Ref: 386e11535909
Ref: library/email mime module-email mime11535909
Ref: 4511535909
Ref: library/email mime translation-repo11535909
Ref: 386f11535909
Ref: library/email mime module-email mime base11537139
Ref: 4811537139
Ref: library/email mime email mime base MIMEBase11537139
Ref: 387011537139
Ref: library/email mime module-email mime nonmultipart11538268
Ref: 4c11538268
Ref: library/email mime email mime nonmultipart MIMENonMultipart11538268
Ref: 380311538268
Ref: library/email mime module-email mime multipart11538758
Ref: 4b11538758
Ref: library/email mime email mime multipart MIMEMultipart11538758
Ref: 387111538758
Ref: library/email mime module-email mime application11540077
Ref: 4611540077
Ref: library/email mime email mime application MIMEApplication11540077
Ref: 387211540077
Ref: library/email mime module-email mime audio11541419
Ref: 4711541419
Ref: library/email mime email mime audio MIMEAudio11541419
Ref: 387311541419
Ref: library/email mime module-email mime image11542973
Ref: 4911542973
Ref: library/email mime email mime image MIMEImage11542973
Ref: 380411542973
Ref: library/email mime module-email mime message11544607
Ref: 4a11544607
Ref: library/email mime email mime message MIMEMessage11544607
Ref: 387411544607
Ref: library/email mime module-email mime text11545291
Ref: 4d11545291
Ref: library/email mime email mime text MIMEText11545291
Ref: e2b11545291
Ref: email mime Creating email and MIME objects from scratch-Footnote-111546918
Node: email header Internationalized headers11546986
Ref: library/email header doc11547219
Ref: 387511547219
Ref: library/email header email-header-internationalized-headers11547219
Ref: 387611547219
Ref: library/email header module-email header11547219
Ref: 4111547219
Ref: library/email header translation-repo11547219
Ref: 387711547219
Ref: library/email header email header Header11549891
Ref: 1a0411549891
Ref: library/email header email header Header append11551742
Ref: 387811551742
Ref: library/email header email header Header encode11553066
Ref: 387911553066
Ref: library/email header email header Header __str__11554698
Ref: 387a11554698
Ref: library/email header email header Header __eq__11555180
Ref: 387b11555180
Ref: library/email header email header Header __ne__11555309
Ref: 387c11555309
Ref: library/email header email header decode_header11555521
Ref: 10fc11555521
Ref: library/email header email header make_header11556987
Ref: 10fd11556987
Ref: email header Internationalized headers-Footnote-111557805
Ref: email header Internationalized headers-Footnote-211557877
Ref: email header Internationalized headers-Footnote-311557936
Ref: email header Internationalized headers-Footnote-411557994
Ref: email header Internationalized headers-Footnote-511558053
Ref: email header Internationalized headers-Footnote-611558112
Ref: email header Internationalized headers-Footnote-711558171
Ref: email header Internationalized headers-Footnote-811558230
Ref: email header Internationalized headers-Footnote-911558289
Ref: email header Internationalized headers-Footnote-1011558348
Ref: email header Internationalized headers-Footnote-1111558408
Ref: email header Internationalized headers-Footnote-1211558468
Ref: email header Internationalized headers-Footnote-1311558528
Ref: email header Internationalized headers-Footnote-1411558588
Ref: email header Internationalized headers-Footnote-1511558648
Node: email charset Representing character sets11558708
Ref: library/email charset doc11558909
Ref: 387d11558909
Ref: library/email charset email-charset-representing-character-sets11558909
Ref: 387e11558909
Ref: library/email charset module-email charset11558909
Ref: 3c11558909
Ref: library/email charset translation-repo11558909
Ref: 387f11558909
Ref: library/email charset email charset Charset11559709
Ref: e2c11559709
Ref: library/email charset email charset Charset input_charset11561228
Ref: 388011561228
Ref: library/email charset email charset Charset header_encoding11561484
Ref: 388111561484
Ref: library/email charset email charset Charset body_encoding11561870
Ref: 388211561870
Ref: library/email charset email charset Charset output_charset11562147
Ref: 388311562147
Ref: library/email charset email charset Charset input_codec11562486
Ref: 388411562486
Ref: library/email charset email charset Charset output_codec11562700
Ref: 388511562700
Ref: library/email charset email charset Charset get_body_encoding11563006
Ref: 388611563006
Ref: library/email charset email charset Charset get_output_charset11563723
Ref: 388711563723
Ref: library/email charset email charset Charset header_encode11563927
Ref: 388811563927
Ref: library/email charset email charset Charset header_encode_lines11564135
Ref: 388911564135
Ref: library/email charset email charset Charset body_encode11564568
Ref: 388a11564568
Ref: library/email charset email charset Charset __str__11564894
Ref: 388b11564894
Ref: library/email charset email charset Charset __eq__11565053
Ref: 388c11565053
Ref: library/email charset email charset Charset __ne__11565183
Ref: 388d11565183
Ref: library/email charset email charset add_charset11565466
Ref: 388e11565466
Ref: library/email charset email charset add_alias11566791
Ref: 389011566791
Ref: library/email charset email charset add_codec11567117
Ref: 388f11567117
Ref: email charset Representing character sets-Footnote-111567511
Node: email encoders Encoders11567584
Ref: library/email encoders doc11567782
Ref: 389111567782
Ref: library/email encoders email-encoders-encoders11567782
Ref: 389211567782
Ref: library/email encoders module-email encoders11567782
Ref: 3e11567782
Ref: library/email encoders translation-repo11567782
Ref: 389311567782
Ref: library/email encoders email encoders encode_quopri11569469
Ref: 389411569469
Ref: library/email encoders email encoders encode_base6411569797
Ref: 389511569797
Ref: library/email encoders email encoders encode_7or8bit11570193
Ref: 389611570193
Ref: library/email encoders email encoders encode_noop11570453
Ref: 389711570453
Ref: email encoders Encoders-Footnote-111570633
Ref: email encoders Encoders-Footnote-211570707
Node: email utils Miscellaneous utilities11570824
Ref: library/email utils doc11571006
Ref: 389811571006
Ref: library/email utils email-utils-miscellaneous-utilities11571006
Ref: 389911571006
Ref: library/email utils module-email utils11571006
Ref: 5011571006
Ref: library/email utils translation-repo11571006
Ref: 389a11571006
Ref: library/email utils email utils localtime11571297
Ref: 2c411571297
Ref: library/email utils email utils make_msgid11571884
Ref: 389b11571884
Ref: library/email utils email utils quote11572781
Ref: 389c11572781
Ref: library/email utils email utils unquote11572960
Ref: 37a711572960
Ref: library/email utils email utils parseaddr11573230
Ref: 1e211573230
Ref: library/email utils email utils formataddr11573797
Ref: 11de11573797
Ref: library/email utils email utils getaddresses11574477
Ref: 1e111574477
Ref: library/email utils email utils parsedate11575323
Ref: 389d11575323
Ref: library/email utils email utils parsedate_tz11575934
Ref: 19c711575934
Ref: library/email utils email utils parsedate_to_datetime11576514
Ref: 110211576514
Ref: library/email utils email utils mktime_tz11577396
Ref: 389e11577396
Ref: library/email utils email utils formatdate11577633
Ref: 14b911577633
Ref: library/email utils email utils format_datetime11578580
Ref: 110111578580
Ref: library/email utils email utils decode_rfc223111579270
Ref: 389f11579270
Ref: library/email utils email utils encode_rfc223111579370
Ref: 38a011579370
Ref: library/email utils email utils collapse_rfc2231_value11579778
Ref: 386111579778
Ref: library/email utils email utils decode_params11580615
Ref: 163c11580615
Ref: email utils Miscellaneous utilities-Footnote-111580871
Ref: email utils Miscellaneous utilities-Footnote-211580942
Ref: email utils Miscellaneous utilities-Footnote-311581001
Ref: email utils Miscellaneous utilities-Footnote-411581060
Ref: email utils Miscellaneous utilities-Footnote-511581119
Ref: email utils Miscellaneous utilities-Footnote-611581178
Ref: email utils Miscellaneous utilities-Footnote-711581451
Ref: email utils Miscellaneous utilities-Footnote-811581510
Ref: email utils Miscellaneous utilities-Footnote-911581569
Ref: email utils Miscellaneous utilities-Footnote-1011581628
Ref: email utils Miscellaneous utilities-Footnote-1111581688
Ref: email utils Miscellaneous utilities-Footnote-1211581748
Node: email iterators Iterators11581808
Ref: library/email iterators doc11581958
Ref: 38a111581958
Ref: library/email iterators email-iterators-iterators11581958
Ref: 38a211581958
Ref: library/email iterators module-email iterators11581958
Ref: 4311581958
Ref: library/email iterators translation-repo11581958
Ref: 38a311581958
Ref: library/email iterators email iterators body_line_iterator11582353
Ref: 38a411582353
Ref: library/email iterators email iterators typed_subpart_iterator11582931
Ref: 38a511582931
Ref: library/email iterators email iterators _structure11583642
Ref: 38a611583642
Ref: email iterators Iterators-Footnote-111585063
Node: json — JSON encoder and decoder11585139
Ref: library/json doc11585344
Ref: 38a711585344
Ref: library/json json-json-encoder-and-decoder11585344
Ref: 38a811585344
Ref: library/json module-json11585344
Ref: 8211585344
Ref: library/json translation-repo11585344
Ref: 38a911585344
Ref: json — JSON encoder and decoder-Footnote-111589971
Ref: json — JSON encoder and decoder-Footnote-211590044
Ref: json — JSON encoder and decoder-Footnote-311590069
Ref: json — JSON encoder and decoder-Footnote-411590128
Ref: json — JSON encoder and decoder-Footnote-511590187
Ref: json — JSON encoder and decoder-Footnote-611590274
Ref: json — JSON encoder and decoder-Footnote-711590323
Ref: json — JSON encoder and decoder-Footnote-811590585
Node: Basic Usage11590611
Ref: library/json basic-usage11590722
Ref: 38ab11590722
Ref: library/json json dump11590765
Ref: d6d11590765
Ref: library/json json dumps11595117
Ref: d6e11595117
Ref: library/json json load11595942
Ref: cda11595942
Ref: library/json json loads11599589
Ref: 95f11599589
Ref: Basic Usage-Footnote-111600300
Node: Encoders and Decoders11600332
Ref: library/json encoders-and-decoders11600466
Ref: 38af11600466
Ref: library/json json JSONDecoder11600529
Ref: d7011600529
Ref: library/json json-to-py-table11600783
Ref: 38ae11600783
Ref: library/json json JSONDecoder decode11603766
Ref: 38b011603766
Ref: library/json json JSONDecoder raw_decode11604018
Ref: 38b111604018
Ref: library/json json JSONEncoder11604382
Ref: d6f11604382
Ref: library/json py-to-json-table11604683
Ref: 38ac11604683
Ref: library/json json JSONEncoder default11609167
Ref: 38ad11609167
Ref: library/json json JSONEncoder encode11609849
Ref: 38b211609849
Ref: library/json json JSONEncoder iterencode11610094
Ref: 38b311610094
Ref: Encoders and Decoders-Footnote-111610391
Node: Exceptions<17>11610423
Ref: library/json exceptions11610586
Ref: 38b411610586
Ref: library/json json JSONDecodeError11610627
Ref: e5311610627
Ref: library/json json JSONDecodeError msg11610768
Ref: 38b511610768
Ref: library/json json JSONDecodeError doc11610835
Ref: 38b611610835
Ref: library/json json JSONDecodeError pos11610903
Ref: 38b711610903
Ref: library/json json JSONDecodeError lineno11610986
Ref: 38b811610986
Ref: library/json json JSONDecodeError colno11611058
Ref: 38b911611058
Node: Standard Compliance and Interoperability11611159
Ref: library/json standard-compliance-and-interoperability11611323
Ref: 38ba11611323
Ref: Standard Compliance and Interoperability-Footnote-111612473
Ref: Standard Compliance and Interoperability-Footnote-211612532
Node: Character Encodings11612619
Ref: library/json character-encodings11612754
Ref: 38bb11612754
Node: Infinite and NaN Number Values11614095
Ref: library/json infinite-and-nan-number-values11614270
Ref: 38bc11614270
Node: Repeated Names Within an Object11615058
Ref: library/json repeated-names-within-an-object11615251
Ref: 38bd11615251
Node: Top-level Non-Object Non-Array Values11615774
Ref: library/json top-level-non-object-non-array-values11615963
Ref: 38be11615963
Ref: Top-level Non-Object Non-Array Values-Footnote-111616617
Ref: Top-level Non-Object Non-Array Values-Footnote-211616676
Node: Implementation Limitations11616735
Ref: library/json implementation-limitations11616884
Ref: 38bf11616884
Node: Command Line Interface11617834
Ref: library/json command-line-interface11617975
Ref: 38c011617975
Ref: library/json json-commandline11617975
Ref: 38aa11617975
Ref: library/json module-json tool11617975
Ref: 8311617975
Ref: Command Line Interface-Footnote-111618872
Node: Command line options11618941
Ref: library/json command-line-options11619020
Ref: 38c211619020
Ref: library/json cmdoption-json tool-arg-infile11619083
Ref: 38c311619083
Ref: library/json cmdoption-json tool-arg-outfile11619559
Ref: 38c411619559
Ref: library/json cmdoption-json tool-sort-keys11619694
Ref: 38c111619694
Ref: library/json cmdoption-json tool-no-ensure-ascii11619808
Ref: 38c511619808
Ref: library/json cmdoption-json tool-json-lines11619971
Ref: 38c611619971
Ref: library/json cmdoption-json tool-indent11620079
Ref: 38c711620079
Ref: library/json cmdoption-json tool-tab11620079
Ref: 38c811620079
Ref: library/json cmdoption-json tool-no-indent11620079
Ref: 38c911620079
Ref: library/json cmdoption-json tool-compact11620079
Ref: 38ca11620079
Ref: library/json cmdoption-json tool-h11620217
Ref: 38cb11620217
Ref: library/json cmdoption-json tool-help11620217
Ref: 38cc11620217
Node: mailbox — Manipulate mailboxes in various formats11620270
Ref: library/mailbox doc11620472
Ref: 38cd11620472
Ref: library/mailbox mailbox-manipulate-mailboxes-in-various-formats11620472
Ref: 38ce11620472
Ref: library/mailbox module-mailbox11620472
Ref: 8b11620472
Ref: library/mailbox translation-repo11620472
Ref: 38cf11620472
Ref: mailbox — Manipulate mailboxes in various formats-Footnote-111621354
Node: Mailbox objects11621421
Ref: library/mailbox id111621548
Ref: 38d011621548
Ref: library/mailbox mailbox-objects11621548
Ref: 38d111621548
Ref: library/mailbox mailbox Mailbox11621607
Ref: 129311621607
Ref: library/mailbox mailbox Mailbox add11624396
Ref: 129211624396
Ref: library/mailbox mailbox Mailbox remove11625181
Ref: 38d211625181
Ref: library/mailbox mailbox Mailbox __delitem__11625211
Ref: 38d611625211
Ref: library/mailbox mailbox Mailbox discard11625246
Ref: 38d311625246
Ref: library/mailbox mailbox Mailbox __setitem__11625754
Ref: 38d711625754
Ref: library/mailbox mailbox Mailbox iterkeys11626633
Ref: 38d811626633
Ref: library/mailbox mailbox Mailbox keys11626719
Ref: 38d911626719
Ref: library/mailbox mailbox Mailbox itervalues11626881
Ref: 38da11626881
Ref: library/mailbox mailbox Mailbox __iter__11626912
Ref: 38db11626912
Ref: library/mailbox mailbox Mailbox values11627392
Ref: 38dc11627392
Ref: library/mailbox mailbox Mailbox iteritems11627558
Ref: 38dd11627558
Ref: library/mailbox mailbox Mailbox items11627979
Ref: 38de11627979
Ref: library/mailbox mailbox Mailbox get11628172
Ref: 38df11628172
Ref: library/mailbox mailbox Mailbox __getitem__11628213
Ref: 38e011628213
Ref: library/mailbox mailbox Mailbox get_message11628781
Ref: 38e111628781
Ref: library/mailbox mailbox Mailbox get_bytes11629070
Ref: 129511629070
Ref: library/mailbox mailbox Mailbox get_string11629305
Ref: 129611629305
Ref: library/mailbox mailbox Mailbox get_file11629644
Ref: 129411629644
Ref: library/mailbox mailbox Mailbox __contains__11630675
Ref: 38e211630675
Ref: library/mailbox mailbox Mailbox __len__11630809
Ref: 38e311630809
Ref: library/mailbox mailbox Mailbox clear11630892
Ref: 38e411630892
Ref: library/mailbox mailbox Mailbox pop11630968
Ref: 38e511630968
Ref: library/mailbox mailbox Mailbox popitem11631406
Ref: 38e611631406
Ref: library/mailbox mailbox Mailbox update11631922
Ref: 38e711631922
Ref: library/mailbox mailbox Mailbox flush11632618
Ref: 175511632618
Ref: library/mailbox mailbox Mailbox lock11632896
Ref: 38d411632896
Ref: library/mailbox mailbox Mailbox unlock11633315
Ref: 38d511633315
Ref: library/mailbox mailbox Mailbox close11633395
Ref: 38e911633395
Node: Maildir objects11633681
Ref: library/mailbox mailbox-maildir11633769
Ref: 38ea11633769
Ref: library/mailbox maildir-objects11633769
Ref: 38eb11633769
Ref: library/mailbox mailbox Maildir11633828
Ref: 41f11633828
Ref: library/mailbox mailbox Maildir colon11635959
Ref: 38ed11635959
Ref: library/mailbox mailbox Maildir list_folders11636767
Ref: 38ee11636767
Ref: library/mailbox mailbox Maildir get_folder11636855
Ref: 38ef11636855
Ref: library/mailbox mailbox Maildir add_folder11637089
Ref: 38f111637089
Ref: library/mailbox mailbox Maildir remove_folder11637240
Ref: 38f211637240
Ref: library/mailbox mailbox Maildir clean11637482
Ref: 38f411637482
Ref: library/mailbox mailbox Maildir get_flags11637718
Ref: 17e111637718
Ref: library/mailbox mailbox Maildir set_flags11638523
Ref: 17e211638523
Ref: library/mailbox mailbox Maildir add_flag11639274
Ref: 17e311639274
Ref: library/mailbox mailbox Maildir remove_flag11639786
Ref: 17e411639786
Ref: library/mailbox mailbox Maildir get_info11640309
Ref: 17df11640309
Ref: library/mailbox mailbox Maildir set_info11641039
Ref: 17e011641039
Ref: library/mailbox mailbox Maildir add11641837
Ref: 38fc11641837
Ref: library/mailbox mailbox Maildir __setitem__11641868
Ref: 38f911641868
Ref: library/mailbox mailbox Maildir update11641912
Ref: 38fd11641912
Ref: library/mailbox mailbox Maildir flush11642325
Ref: 38fe11642325
Ref: library/mailbox mailbox Maildir lock11642460
Ref: 38ff11642460
Ref: library/mailbox mailbox Maildir unlock11642485
Ref: 390011642485
Ref: library/mailbox mailbox Maildir close11642618
Ref: 390111642618
Ref: library/mailbox mailbox Maildir get_file11642809
Ref: 390211642809
Ref: Maildir objects-Footnote-111643345
Ref: Maildir objects-Footnote-211643394
Node: mbox objects11643438
Ref: library/mailbox mailbox-mbox11643545
Ref: 390311643545
Ref: library/mailbox mbox-objects11643545
Ref: 390411643545
Ref: library/mailbox mailbox mbox11643598
Ref: 179211643598
Ref: library/mailbox mailbox mbox get_bytes11645017
Ref: 390511645017
Ref: library/mailbox mailbox mbox get_file11645314
Ref: 390611645314
Ref: library/mailbox mailbox mbox get_string11645797
Ref: 390711645797
Ref: library/mailbox mailbox mbox lock11646095
Ref: 390811646095
Ref: library/mailbox mailbox mbox unlock11646120
Ref: 390911646120
Ref: mbox objects-Footnote-111646697
Ref: mbox objects-Footnote-211646757
Ref: mbox objects-Footnote-311646809
Node: MH objects11646887
Ref: library/mailbox mailbox-mh11646992
Ref: 390a11646992
Ref: library/mailbox mh-objects11646992
Ref: 390b11646992
Ref: library/mailbox mailbox MH11647041
Ref: 17c611647041
Ref: library/mailbox mailbox MH list_folders11648578
Ref: 390d11648578
Ref: library/mailbox mailbox MH get_folder11648666
Ref: 390e11648666
Ref: library/mailbox mailbox MH add_folder11648896
Ref: 390f11648896
Ref: library/mailbox mailbox MH remove_folder11649043
Ref: 391011649043
Ref: library/mailbox mailbox MH get_sequences11649285
Ref: 391111649285
Ref: library/mailbox mailbox MH set_sequences11649462
Ref: 391211649462
Ref: library/mailbox mailbox MH pack11649700
Ref: 391311649700
Ref: library/mailbox mailbox MH remove11650115
Ref: 391411650115
Ref: library/mailbox mailbox MH __delitem__11650145
Ref: 391511650145
Ref: library/mailbox mailbox MH discard11650180
Ref: 391611650180
Ref: library/mailbox mailbox MH lock11650389
Ref: 391711650389
Ref: library/mailbox mailbox MH unlock11650414
Ref: 391811650414
Ref: library/mailbox mailbox MH get_file11650789
Ref: 391911650789
Ref: library/mailbox mailbox MH flush11650981
Ref: 391a11650981
Ref: library/mailbox mailbox MH close11651111
Ref: 391b11651111
Ref: MH objects-Footnote-111651571
Ref: MH objects-Footnote-211651607
Node: Babyl objects11651652
Ref: library/mailbox babyl-objects11651757
Ref: 391c11651757
Ref: library/mailbox mailbox-babyl11651757
Ref: 391d11651757
Ref: library/mailbox mailbox Babyl11651812
Ref: 391e11651812
Ref: library/mailbox mailbox Babyl get_labels11653376
Ref: 392011653376
Ref: library/mailbox mailbox Babyl get_file11653903
Ref: 392111653903
Ref: library/mailbox mailbox Babyl lock11654423
Ref: 392211654423
Ref: library/mailbox mailbox Babyl unlock11654448
Ref: 392311654448
Ref: Babyl objects-Footnote-111654842
Ref: Babyl objects-Footnote-211654886
Node: MMDF objects11654964
Ref: library/mailbox mailbox-mmdf11655050
Ref: 392411655050
Ref: library/mailbox mmdf-objects11655050
Ref: 392511655050
Ref: library/mailbox mailbox MMDF11655103
Ref: 179311655103
Ref: library/mailbox mailbox MMDF get_bytes11656361
Ref: 392711656361
Ref: library/mailbox mailbox MMDF get_file11656658
Ref: 392811656658
Ref: library/mailbox mailbox MMDF lock11657141
Ref: 392911657141
Ref: library/mailbox mailbox MMDF unlock11657166
Ref: 392a11657166
Ref: MMDF objects-Footnote-111657603
Ref: MMDF objects-Footnote-211657663
Node: Message objects11657706
Ref: library/mailbox mailbox-message-objects11657856
Ref: 392b11657856
Ref: library/mailbox message-objects11657856
Ref: 392c11657856
Ref: library/mailbox mailbox Message11657915
Ref: 129711657915
Ref: Message objects-Footnote-111659960
Node: MaildirMessage objects11660019
Ref: library/mailbox mailbox-maildirmessage11660121
Ref: 392d11660121
Ref: library/mailbox maildirmessage-objects11660121
Ref: 392e11660121
Ref: library/mailbox mailbox MaildirMessage11660194
Ref: 38ec11660194
Ref: library/mailbox mailbox MaildirMessage get_subdir11662044
Ref: 392f11662044
Ref: library/mailbox mailbox MaildirMessage set_subdir11662558
Ref: 393011662558
Ref: library/mailbox mailbox MaildirMessage get_flags11662729
Ref: 38f511662729
Ref: library/mailbox mailbox MaildirMessage set_flags11663201
Ref: 38f611663201
Ref: library/mailbox mailbox MaildirMessage add_flag11663305
Ref: 38f711663305
Ref: library/mailbox mailbox MaildirMessage remove_flag11663655
Ref: 38f811663655
Ref: library/mailbox mailbox MaildirMessage get_date11664011
Ref: 393111664011
Ref: library/mailbox mailbox MaildirMessage set_date11664167
Ref: 393211664167
Ref: library/mailbox mailbox MaildirMessage get_info11664332
Ref: 38fa11664332
Ref: library/mailbox mailbox MaildirMessage set_info11664555
Ref: 38fb11664555
Node: mboxMessage objects11667352
Ref: library/mailbox mailbox-mboxmessage11667480
Ref: 393311667480
Ref: library/mailbox mboxmessage-objects11667480
Ref: 393411667480
Ref: library/mailbox mailbox mboxMessage11667547
Ref: 378f11667547
Ref: library/mailbox mailbox mboxMessage get_from11669343
Ref: 393511669343
Ref: library/mailbox mailbox mboxMessage set_from11669574
Ref: 393611669574
Ref: library/mailbox mailbox mboxMessage get_flags11670112
Ref: 393711670112
Ref: library/mailbox mailbox mboxMessage set_flags11670460
Ref: 393811670460
Ref: library/mailbox mailbox mboxMessage add_flag11670751
Ref: 393911670751
Ref: library/mailbox mailbox mboxMessage remove_flag11670971
Ref: 393a11670971
Node: MHMessage objects11673943
Ref: library/mailbox mailbox-mhmessage11674069
Ref: 393b11674069
Ref: library/mailbox mhmessage-objects11674069
Ref: 393c11674069
Ref: library/mailbox mailbox MHMessage11674134
Ref: 390c11674134
Ref: library/mailbox mailbox MHMessage get_sequences11675094
Ref: 393d11675094
Ref: library/mailbox mailbox MHMessage set_sequences11675217
Ref: 393e11675217
Ref: library/mailbox mailbox MHMessage add_sequence11675325
Ref: 393f11675325
Ref: library/mailbox mailbox MHMessage remove_sequence11675455
Ref: 394011675455
Node: BabylMessage objects11677320
Ref: library/mailbox babylmessage-objects11677446
Ref: 394111677446
Ref: library/mailbox mailbox-babylmessage11677446
Ref: 394211677446
Ref: library/mailbox mailbox BabylMessage11677517
Ref: 391f11677517
Ref: library/mailbox mailbox BabylMessage get_labels11678872
Ref: 394311678872
Ref: library/mailbox mailbox BabylMessage set_labels11678955
Ref: 394411678955
Ref: library/mailbox mailbox BabylMessage add_label11679055
Ref: 394511679055
Ref: library/mailbox mailbox BabylMessage remove_label11679152
Ref: 394611679152
Ref: library/mailbox mailbox BabylMessage get_visible11679257
Ref: 394711679257
Ref: library/mailbox mailbox BabylMessage set_visible11679425
Ref: 394811679425
Ref: library/mailbox mailbox BabylMessage update_visible11679776
Ref: 394911679776
Node: MMDFMessage objects11682216
Ref: library/mailbox mailbox-mmdfmessage11682316
Ref: 394a11682316
Ref: library/mailbox mmdfmessage-objects11682316
Ref: 394b11682316
Ref: library/mailbox mailbox MMDFMessage11682385
Ref: 392611682385
Ref: library/mailbox mailbox MMDFMessage get_from11684065
Ref: 394c11684065
Ref: library/mailbox mailbox MMDFMessage set_from11684296
Ref: 394d11684296
Ref: library/mailbox mailbox MMDFMessage get_flags11684834
Ref: 394e11684834
Ref: library/mailbox mailbox MMDFMessage set_flags11685182
Ref: 394f11685182
Ref: library/mailbox mailbox MMDFMessage add_flag11685473
Ref: 395011685473
Ref: library/mailbox mailbox MMDFMessage remove_flag11685693
Ref: 395111685693
Node: Exceptions<18>11688666
Ref: library/mailbox exceptions11688813
Ref: 395211688813
Ref: library/mailbox mailbox Error11688930
Ref: 395311688930
Ref: library/mailbox mailbox NoSuchMailboxError11689023
Ref: 38f011689023
Ref: library/mailbox mailbox NotEmptyError11689330
Ref: 38f311689330
Ref: library/mailbox mailbox ExternalClashError11689492
Ref: 38e811689492
Ref: library/mailbox mailbox FormatError11689798
Ref: 395411689798
Node: Examples<23>11689995
Ref: library/mailbox examples11690118
Ref: 395511690118
Ref: library/mailbox mailbox-examples11690118
Ref: 395611690118
Node: mimetypes — Map filenames to MIME types11692396
Ref: library/mimetypes doc11692618
Ref: 395711692618
Ref: library/mimetypes mimetypes-map-filenames-to-mime-types11692618
Ref: 395811692618
Ref: library/mimetypes module-mimetypes11692618
Ref: 8f11692618
Ref: library/mimetypes translation-repo11692618
Ref: 395911692618
Ref: library/mimetypes mimetypes guess_type11693493
Ref: 20811693493
Ref: library/mimetypes mimetypes guess_file_type11694980
Ref: 20711694980
Ref: library/mimetypes mimetypes guess_all_extensions11695311
Ref: 19f011695311
Ref: library/mimetypes mimetypes guess_extension11695908
Ref: 395b11695908
Ref: library/mimetypes mimetypes init11696649
Ref: 395a11696649
Ref: library/mimetypes mimetypes read_mime_types11697611
Ref: 1ad111697611
Ref: library/mimetypes mimetypes add_type11697988
Ref: 395d11697988
Ref: library/mimetypes mimetypes inited11698445
Ref: 395e11698445
Ref: library/mimetypes mimetypes knownfiles11698615
Ref: 395c11698615
Ref: library/mimetypes mimetypes suffix_map11698825
Ref: 395f11698825
Ref: library/mimetypes mimetypes encodings_map11699175
Ref: 396011699175
Ref: library/mimetypes mimetypes types_map11699274
Ref: 396111699274
Ref: library/mimetypes mimetypes common_types11699365
Ref: 396211699365
Ref: mimetypes — Map filenames to MIME types-Footnote-111699907
Ref: mimetypes — Map filenames to MIME types-Footnote-211699976
Node: MimeTypes Objects11700047
Ref: library/mimetypes id111700142
Ref: 396311700142
Ref: library/mimetypes mimetypes-objects11700142
Ref: 396411700142
Ref: library/mimetypes mimetypes MimeTypes11700386
Ref: 154a11700386
Ref: library/mimetypes mimetypes MimeTypes suffix_map11701072
Ref: 396711701072
Ref: library/mimetypes mimetypes MimeTypes encodings_map11701554
Ref: 396811701554
Ref: library/mimetypes mimetypes MimeTypes types_map11701767
Ref: 396911701767
Ref: library/mimetypes mimetypes MimeTypes types_map_inv11702103
Ref: 396a11702103
Ref: library/mimetypes mimetypes MimeTypes guess_extension11702453
Ref: 396b11702453
Ref: library/mimetypes mimetypes MimeTypes guess_type11702631
Ref: 1bc811702631
Ref: library/mimetypes mimetypes MimeTypes guess_file_type11702797
Ref: 396c11702797
Ref: library/mimetypes mimetypes MimeTypes guess_all_extensions11703011
Ref: 396d11703011
Ref: library/mimetypes mimetypes MimeTypes read11703199
Ref: 396511703199
Ref: library/mimetypes mimetypes MimeTypes readfp11703512
Ref: 396611703512
Ref: library/mimetypes mimetypes MimeTypes read_windows_registry11703843
Ref: 396e11703843
Ref: library/mimetypes mimetypes MimeTypes add_type11704187
Ref: 396f11704187
Node: base64 — Base16 Base32 Base64 Base85 Data Encodings11704678
Ref: library/base64 doc11704894
Ref: 397011704894
Ref: library/base64 base64-base16-base32-base64-base85-data-encodings11704894
Ref: 397111704894
Ref: library/base64 module-base6411704894
Ref: e11704894
Ref: library/base64 translation-repo11704894
Ref: 397211704894
Ref: base64 — Base16 Base32 Base64 Base85 Data Encodings-Footnote-111706590
Ref: base64 — Base16 Base32 Base64 Base85 Data Encodings-Footnote-211706656
Ref: base64 — Base16 Base32 Base64 Base85 Data Encodings-Footnote-311706715
Ref: base64 — Base16 Base32 Base64 Base85 Data Encodings-Footnote-411706774
Ref: base64 — Base16 Base32 Base64 Base85 Data Encodings-Footnote-511706833
Node: RFC 4648 Encodings11706892
Ref: library/base64 base64-rfc-464811707025
Ref: 397311707025
Ref: library/base64 rfc-4648-encodings11707025
Ref: 397611707025
Ref: library/base64 base64 b64encode11707255
Ref: 397711707255
Ref: library/base64 base64 b64decode11707939
Ref: 15af11707939
Ref: library/base64 base64 standard_b64encode11708931
Ref: 397811708931
Ref: library/base64 base64 standard_b64decode11709104
Ref: 397911709104
Ref: library/base64 base64 urlsafe_b64encode11709293
Ref: 397a11709293
Ref: library/base64 base64 urlsafe_b64decode11709633
Ref: 397b11709633
Ref: library/base64 base64 b32encode11709950
Ref: 397c11709950
Ref: library/base64 base64 b32decode11710096
Ref: 106011710096
Ref: library/base64 base64 b32hexencode11711092
Ref: 7e811711092
Ref: library/base64 base64 b32hexdecode11711270
Ref: 7e911711270
Ref: library/base64 base64 b16encode11711719
Ref: 397d11711719
Ref: library/base64 base64 b16decode11711865
Ref: 397e11711865
Ref: RFC 4648 Encodings-Footnote-111712390
Ref: RFC 4648 Encodings-Footnote-211712449
Ref: RFC 4648 Encodings-Footnote-311712508
Ref: RFC 4648 Encodings-Footnote-411712567
Node: Base85 Encodings11712626
Ref: library/base64 base64-base-8511712784
Ref: 397411712784
Ref: library/base64 base85-encodings11712784
Ref: 397f11712784
Ref: library/base64 base64 a85encode11713559
Ref: f5511713559
Ref: library/base64 base64 a85decode11714561
Ref: f5611714561
Ref: library/base64 base64 b85encode11715394
Ref: f5711715394
Ref: library/base64 base64 b85decode11715748
Ref: f5811715748
Ref: library/base64 base64 z85encode11715991
Ref: 14f11715991
Ref: library/base64 base64 z85decode11716236
Ref: 15011716236
Ref: Base85 Encodings-Footnote-111716515
Ref: Base85 Encodings-Footnote-211716555
Node: Legacy Interface11716595
Ref: library/base64 base64-legacy11716761
Ref: 397511716761
Ref: library/base64 legacy-interface11716761
Ref: 398011716761
Ref: library/base64 base64 decode11716814
Ref: 398111716814
Ref: library/base64 base64 decodebytes11717123
Ref: 95e11717123
Ref: library/base64 base64 encode11717353
Ref: 398211717353
Ref: library/base64 base64 encodebytes11717866
Ref: 95d11717866
Ref: Legacy Interface-Footnote-111718538
Ref: Legacy Interface-Footnote-211718597
Node: Security Considerations<2>11718656
Ref: library/base64 base64-security11718797
Ref: 398311718797
Ref: library/base64 security-considerations11718797
Ref: 398411718797
Ref: Security Considerations<2>-Footnote-111719459
Ref: Security Considerations<2>-Footnote-211719518
Node: binascii — Convert between binary and ASCII11719577
Ref: library/binascii doc11719807
Ref: 398511719807
Ref: library/binascii binascii-convert-between-binary-and-ascii11719807
Ref: 398611719807
Ref: library/binascii module-binascii11719807
Ref: 1011719807
Ref: library/binascii translation-repo11719807
Ref: 398711719807
Ref: library/binascii binascii a2b_uu11720795
Ref: 398811720795
Ref: library/binascii binascii b2a_uu11721045
Ref: b3911721045
Ref: library/binascii binascii a2b_base6411721424
Ref: 15ae11721424
Ref: library/binascii binascii b2a_base6411722090
Ref: ca211722090
Ref: library/binascii binascii a2b_qp11722440
Ref: 398911722440
Ref: library/binascii binascii b2a_qp11722737
Ref: 398a11722737
Ref: library/binascii binascii crc_hqx11723505
Ref: 73711723505
Ref: library/binascii binascii crc3211723810
Ref: 17a911723810
Ref: library/binascii binascii b2a_hex11724485
Ref: 25cd11724485
Ref: library/binascii binascii hexlify11724549
Ref: 398b11724549
Ref: library/binascii binascii a2b_hex11725746
Ref: 25ce11725746
Ref: library/binascii binascii unhexlify11725786
Ref: 1bd711725786
Ref: library/binascii binascii Error11726315
Ref: 106111726315
Ref: library/binascii binascii Incomplete11726419
Ref: 398c11726419
Ref: binascii — Convert between binary and ASCII-Footnote-111726884
Ref: binascii — Convert between binary and ASCII-Footnote-211726943
Ref: binascii — Convert between binary and ASCII-Footnote-311727002
Node: quopri — Encode and decode MIME quoted-printable data11727061
Ref: library/quopri doc11727229
Ref: 398d11727229
Ref: library/quopri module-quopri11727229
Ref: b711727229
Ref: library/quopri quopri-encode-and-decode-mime-quoted-printable-data11727229
Ref: 398e11727229
Ref: library/quopri translation-repo11727229
Ref: 398f11727229
Ref: library/quopri quopri decode11727964
Ref: 25d011727964
Ref: library/quopri quopri encode11728504
Ref: 25cf11728504
Ref: library/quopri quopri decodestring11729161
Ref: 399011729161
Ref: library/quopri quopri encodestring11729353
Ref: 399111729353
Ref: quopri — Encode and decode MIME quoted-printable data-Footnote-111729792
Ref: quopri — Encode and decode MIME quoted-printable data-Footnote-211729858
Ref: quopri — Encode and decode MIME quoted-printable data-Footnote-311729917
Ref: quopri — Encode and decode MIME quoted-printable data-Footnote-411729976
Ref: quopri — Encode and decode MIME quoted-printable data-Footnote-511730035
Node: Structured Markup Processing Tools11730094
Ref: library/markup doc11730262
Ref: 399211730262
Ref: library/markup markup11730262
Ref: 399311730262
Ref: library/markup structured-markup-processing-tools11730262
Ref: 399411730262
Ref: library/markup translation-repo11730262
Ref: 399511730262
Node: html — HyperText Markup Language support11731805
Ref: library/html doc11731971
Ref: 399611731971
Ref: library/html html-hypertext-markup-language-support11731971
Ref: 399711731971
Ref: library/html module-html11731971
Ref: 6b11731971
Ref: library/html html escape11732237
Ref: 104911732237
Ref: library/html html unescape11732817
Ref: 96111732817
Ref: html — HyperText Markup Language support-Footnote-111733521
Node: html parser — Simple HTML and XHTML parser11733594
Ref: library/html parser doc11733823
Ref: 399811733823
Ref: library/html parser html-parser-simple-html-and-xhtml-parser11733823
Ref: 399911733823
Ref: library/html parser module-html parser11733823
Ref: 6d11733823
Ref: library/html parser translation-repo11733823
Ref: 399a11733823
Ref: library/html parser html parser HTMLParser11734199
Ref: 87e11734199
Ref: html parser — Simple HTML and XHTML parser-Footnote-111735579
Node: Example HTML Parser Application11735650
Ref: library/html parser example-html-parser-application11735789
Ref: 399b11735789
Node: HTMLParser Methods11736995
Ref: library/html parser htmlparser-methods11737155
Ref: 399c11737155
Ref: library/html parser html parser HTMLParser feed11737282
Ref: 399d11737282
Ref: library/html parser html parser HTMLParser close11737549
Ref: 164d11737549
Ref: library/html parser html parser HTMLParser reset11737904
Ref: 399e11737904
Ref: library/html parser html parser HTMLParser getpos11738047
Ref: 399f11738047
Ref: library/html parser html parser HTMLParser get_starttag_text11738126
Ref: 39a011738126
Ref: library/html parser html parser HTMLParser handle_starttag11738697
Ref: 39a211738697
Ref: library/html parser html parser HTMLParser handle_endtag11739501
Ref: 39a311739501
Ref: library/html parser html parser HTMLParser handle_startendtag11739708
Ref: 39a111739708
Ref: library/html parser html parser HTMLParser handle_data11740109
Ref: 39a411740109
Ref: library/html parser html parser HTMLParser handle_entityref11740293
Ref: 39a511740293
Ref: library/html parser html parser HTMLParser handle_charref11740591
Ref: 39a611740591
Ref: library/html parser html parser HTMLParser handle_comment11741031
Ref: 39a711741031
Ref: library/html parser html parser HTMLParser handle_decl11741557
Ref: 39a811741557
Ref: library/html parser html parser HTMLParser handle_pi11741841
Ref: 39a911741841
Ref: library/html parser html parser HTMLParser unknown_decl11742531
Ref: 39aa11742531
Node: Examples<24>11742893
Ref: library/html parser examples11743013
Ref: 39ab11743013
Ref: library/html parser htmlparser-examples11743013
Ref: 39ac11743013
Node: html entities — Definitions of HTML general entities11746572
Ref: library/html entities doc11746781
Ref: 39ad11746781
Ref: library/html entities html-entities-definitions-of-html-general-entities11746781
Ref: 39ae11746781
Ref: library/html entities module-html entities11746781
Ref: 6c11746781
Ref: library/html entities translation-repo11746781
Ref: 39af11746781
Ref: library/html entities html entities html511747163
Ref: 111611747163
Ref: library/html entities html entities entitydefs11747650
Ref: 39b211747650
Ref: library/html entities html entities name2codepoint11747789
Ref: 39b011747789
Ref: library/html entities html entities codepoint2name11747910
Ref: 39b111747910
Ref: html entities — Definitions of HTML general entities-Footnote-111748058
Ref: html entities — Definitions of HTML general entities-Footnote-211748131
Node: XML Processing Modules11748237
Ref: library/xml doc11748451
Ref: 39b311748451
Ref: library/xml module-xml11748451
Ref: 12011748451
Ref: library/xml translation-repo11748451
Ref: 39b411748451
Ref: library/xml xml11748451
Ref: 39b511748451
Ref: library/xml xml-processing-modules11748451
Ref: 39b611748451
Ref: library/xml xml-security11749652
Ref: 39b711749652
Ref: XML Processing Modules-Footnote-111749715
Node: XML security11749776
Ref: library/xml id111749847
Ref: 39b811749847
Ref: library/xml xml-vulnerabilities11749847
Ref: 39b911749847
Ref: XML security-Footnote-111752314
Ref: XML security-Footnote-211752359
Ref: XML security-Footnote-311752412
Ref: XML security-Footnote-411752465
Ref: XML security-Footnote-511752512
Node: xml etree ElementTree — The ElementTree XML API11752568
Ref: library/xml etree elementtree doc11752769
Ref: 39ba11752769
Ref: library/xml etree elementtree module-xml etree ElementTree11752769
Ref: 12511752769
Ref: library/xml etree elementtree translation-repo11752769
Ref: 39bb11752769
Ref: library/xml etree elementtree xml-etree-elementtree-the-elementtree-xml-api11752769
Ref: 39bc11752769
Ref: xml etree ElementTree — The ElementTree XML API-Footnote-111753560
Node: Tutorial<3>11753642
Ref: library/xml etree elementtree tutorial11753761
Ref: 39bd11753761
Node: XML tree and elements11754181
Ref: library/xml etree elementtree xml-tree-and-elements11754270
Ref: 39be11754270
Node: Parsing XML11754836
Ref: library/xml etree elementtree elementtree-parsing-xml11754967
Ref: 39bf11754967
Ref: library/xml etree elementtree parsing-xml11754967
Ref: 39c011754967
Node: Pull API for non-blocking parsing11757444
Ref: library/xml etree elementtree elementtree-pull-parsing11757582
Ref: 102f11757582
Ref: library/xml etree elementtree pull-api-for-non-blocking-parsing11757582
Ref: 39c211757582
Node: Finding interesting elements11759697
Ref: library/xml etree elementtree finding-interesting-elements11759845
Ref: 39c511759845
Node: Modifying an XML File11761087
Ref: library/xml etree elementtree modifying-an-xml-file11761224
Ref: 39c811761224
Node: Building XML documents11764168
Ref: library/xml etree elementtree building-xml-documents11764304
Ref: 39cb11764304
Node: Parsing XML with Namespaces11764673
Ref: library/xml etree elementtree parsing-xml-with-namespaces11764779
Ref: 39cd11764779
Ref: Parsing XML with Namespaces-Footnote-111767094
Ref: Parsing XML with Namespaces-Footnote-211767146
Node: XPath support11767198
Ref: library/xml etree elementtree elementtree-xpath11767338
Ref: bcb11767338
Ref: library/xml etree elementtree xpath-support11767338
Ref: 39ce11767338
Ref: XPath support-Footnote-111767699
Node: Example<8>11767735
Ref: library/xml etree elementtree example11767826
Ref: 39cf11767826
Node: Supported XPath syntax11768845
Ref: library/xml etree elementtree supported-xpath-syntax11768936
Ref: 39d011768936
Node: Reference<4>11773919
Ref: library/xml etree elementtree reference11774064
Ref: 39d111774064
Node: Functions<9>11774142
Ref: library/xml etree elementtree elementtree-functions11774203
Ref: 39d211774203
Ref: library/xml etree elementtree functions11774203
Ref: 39d311774203
Ref: library/xml etree elementtree xml etree ElementTree canonicalize11774244
Ref: a6111774244
Ref: library/xml etree elementtree xml etree ElementTree Comment11776628
Ref: 39d411776628
Ref: library/xml etree elementtree xml etree ElementTree dump11777313
Ref: 39d511777313
Ref: library/xml etree elementtree xml etree ElementTree fromstring11777780
Ref: 39c111777780
Ref: library/xml etree elementtree xml etree ElementTree fromstringlist11778139
Ref: 121611778139
Ref: library/xml etree elementtree xml etree ElementTree indent11778559
Ref: 39d711778559
Ref: library/xml etree elementtree xml etree ElementTree iselement11779087
Ref: 39d811779087
Ref: library/xml etree elementtree xml etree ElementTree iterparse11779301
Ref: 27311779301
Ref: library/xml etree elementtree xml etree ElementTree parse11781437
Ref: 39d911781437
Ref: library/xml etree elementtree xml etree ElementTree ProcessingInstruction11781781
Ref: 39da11781781
Ref: library/xml etree elementtree xml etree ElementTree register_namespace11782509
Ref: 121711782509
Ref: library/xml etree elementtree xml etree ElementTree SubElement11782940
Ref: 39cc11782940
Ref: library/xml etree elementtree xml etree ElementTree tostring11783510
Ref: 103011783510
Ref: library/xml etree elementtree xml etree ElementTree tostringlist11784603
Ref: 103111784603
Ref: library/xml etree elementtree xml etree ElementTree XML11785868
Ref: 39d611785868
Ref: library/xml etree elementtree xml etree ElementTree XMLID11786262
Ref: 39db11786262
Ref: Functions<9>-Footnote-111786737
Ref: Functions<9>-Footnote-211786778
Ref: Functions<9>-Footnote-311787087
Node: XInclude support11787396
Ref: library/xml etree elementtree elementtree-xinclude11787540
Ref: 39dc11787540
Ref: library/xml etree elementtree xinclude-support11787540
Ref: 39dd11787540
Ref: XInclude support-Footnote-111787905
Node: Example<9>11787945
Ref: library/xml etree elementtree id311788008
Ref: 39de11788008
Node: Reference<5>11789816
Ref: library/xml etree elementtree id411789939
Ref: 39df11789939
Node: Functions<10>11790182
Ref: library/xml etree elementtree elementinclude-functions11790268
Ref: 39e011790268
Ref: library/xml etree elementtree id511790268
Ref: 39e111790268
Ref: library/xml etree elementtree module-xml etree ElementInclude11790309
Ref: 12411790309
Ref: library/xml etree elementtree xml etree ElementInclude default_loader11790309
Ref: 39e211790309
Ref: library/xml etree elementtree xml etree ElementInclude include11790904
Ref: 39e311790904
Node: Element Objects11791783
Ref: library/xml etree elementtree element-objects11791897
Ref: 39e411791897
Ref: library/xml etree elementtree elementtree-element-objects11791897
Ref: 39e511791897
Ref: library/xml etree elementtree xml etree ElementTree Element11791950
Ref: 31011791950
Ref: library/xml etree elementtree xml etree ElementTree Element tag11792432
Ref: 139911792432
Ref: library/xml etree elementtree xml etree ElementTree Element text11792577
Ref: 39c611792577
Ref: library/xml etree elementtree xml etree ElementTree Element tail11792602
Ref: 39e611792602
Ref: library/xml etree elementtree xml etree ElementTree Element attrib11793718
Ref: 39e711793718
Ref: library/xml etree elementtree xml etree ElementTree Element clear11794262
Ref: 39e811794262
Ref: library/xml etree elementtree xml etree ElementTree Element get11794455
Ref: 39c711794455
Ref: library/xml etree elementtree xml etree ElementTree Element items11794643
Ref: 39e911794643
Ref: library/xml etree elementtree xml etree ElementTree Element keys11794812
Ref: 39ea11794812
Ref: library/xml etree elementtree xml etree ElementTree Element set11794954
Ref: 39c911794954
Ref: library/xml etree elementtree xml etree ElementTree Element append11795127
Ref: 39ca11795127
Ref: library/xml etree elementtree xml etree ElementTree Element extend11795358
Ref: 121811795358
Ref: library/xml etree elementtree xml etree ElementTree Element find11795574
Ref: 166a11795574
Ref: library/xml etree elementtree xml etree ElementTree Element findall11795996
Ref: 166c11795996
Ref: library/xml etree elementtree xml etree ElementTree Element findtext11796415
Ref: 166b11796415
Ref: library/xml etree elementtree xml etree ElementTree Element insert11797019
Ref: 39eb11797019
Ref: library/xml etree elementtree xml etree ElementTree Element iter11797225
Ref: 139a11797225
Ref: library/xml etree elementtree xml etree ElementTree Element iterfind11797717
Ref: 121911797717
Ref: library/xml etree elementtree xml etree ElementTree Element itertext11798051
Ref: 121a11798051
Ref: library/xml etree elementtree xml etree ElementTree Element makeelement11798276
Ref: 39ec11798276
Ref: library/xml etree elementtree xml etree ElementTree Element remove11798499
Ref: 166e11798499
Ref: Element Objects-Footnote-111801244
Node: ElementTree Objects11801287
Ref: library/xml etree elementtree elementtree-elementtree-objects11801401
Ref: 39ed11801401
Ref: library/xml etree elementtree elementtree-objects11801401
Ref: 39ee11801401
Ref: library/xml etree elementtree xml etree ElementTree ElementTree11801462
Ref: 95811801462
Ref: library/xml etree elementtree xml etree ElementTree ElementTree _setroot11801814
Ref: 39ef11801814
Ref: library/xml etree elementtree xml etree ElementTree ElementTree find11802063
Ref: 39f011802063
Ref: library/xml etree elementtree xml etree ElementTree ElementTree findall11802202
Ref: 39f111802202
Ref: library/xml etree elementtree xml etree ElementTree ElementTree findtext11802347
Ref: 39f211802347
Ref: library/xml etree elementtree xml etree ElementTree ElementTree getroot11802508
Ref: 39f311802508
Ref: library/xml etree elementtree xml etree ElementTree ElementTree iter11802588
Ref: 39f411802588
Ref: library/xml etree elementtree xml etree ElementTree ElementTree iterfind11802858
Ref: 39f511802858
Ref: library/xml etree elementtree xml etree ElementTree ElementTree parse11803038
Ref: 39f611803038
Ref: library/xml etree elementtree xml etree ElementTree ElementTree write11803384
Ref: aaa11803384
Ref: ElementTree Objects-Footnote-111806178
Node: QName Objects11806487
Ref: library/xml etree elementtree elementtree-qname-objects11806605
Ref: 39f711806605
Ref: library/xml etree elementtree qname-objects11806605
Ref: 39f811806605
Ref: library/xml etree elementtree xml etree ElementTree QName11806654
Ref: 39f911806654
Node: TreeBuilder Objects11807160
Ref: library/xml etree elementtree elementtree-treebuilder-objects11807276
Ref: 39fa11807276
Ref: library/xml etree elementtree treebuilder-objects11807276
Ref: 39fb11807276
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder11807337
Ref: a6311807337
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder close11808455
Ref: 39fc11808455
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder data11808617
Ref: 39fd11808617
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder end11808781
Ref: 121b11808781
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder start11808914
Ref: 1b1511808914
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder comment11809116
Ref: 39fe11809116
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder pi11809314
Ref: 39ff11809314
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder doctype11809643
Ref: aac11809643
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder start_ns11809963
Ref: 3a0011809963
Ref: library/xml etree elementtree xml etree ElementTree TreeBuilder end_ns11810359
Ref: 3a0111810359
Ref: library/xml etree elementtree xml etree ElementTree C14NWriterTarget11810608
Ref: 3a0211810608
Ref: TreeBuilder Objects-Footnote-111811157
Node: XMLParser Objects11811198
Ref: library/xml etree elementtree elementtree-xmlparser-objects11811322
Ref: 3a0311811322
Ref: library/xml etree elementtree xmlparser-objects11811322
Ref: 3a0411811322
Ref: library/xml etree elementtree xml etree ElementTree XMLParser11811379
Ref: a6211811379
Ref: library/xml etree elementtree xml etree ElementTree XMLParser close11812094
Ref: 3a0611812094
Ref: library/xml etree elementtree xml etree ElementTree XMLParser feed11812350
Ref: 3a0511812350
Ref: library/xml etree elementtree xml etree ElementTree XMLParser flush11812442
Ref: 26f11812442
Ref: XMLParser Objects-Footnote-111815046
Node: XMLPullParser Objects11815355
Ref: library/xml etree elementtree elementtree-xmlpullparser-objects11815474
Ref: 3a0711815474
Ref: library/xml etree elementtree xmlpullparser-objects11815474
Ref: 3a0811815474
Ref: library/xml etree elementtree xml etree ElementTree XMLPullParser11815539
Ref: 102e11815539
Ref: library/xml etree elementtree xml etree ElementTree XMLPullParser feed11816226
Ref: 39c311816226
Ref: library/xml etree elementtree xml etree ElementTree XMLPullParser flush11816308
Ref: 27011816308
Ref: library/xml etree elementtree xml etree ElementTree XMLPullParser close11817139
Ref: 3a0911817139
Ref: library/xml etree elementtree xml etree ElementTree XMLPullParser read_events11817450
Ref: 39c411817450
Node: Exceptions<19>11819147
Ref: library/xml etree elementtree exceptions11819240
Ref: 3a0a11819240
Ref: library/xml etree elementtree xml etree ElementTree ParseError11819283
Ref: 12be11819283
Ref: library/xml etree elementtree xml etree ElementTree ParseError code11819611
Ref: 3a0b11819611
Ref: library/xml etree elementtree xml etree ElementTree ParseError position11819816
Ref: 3a0c11819816
Node: xml dom — The Document Object Model API11819941
Ref: library/xml dom doc11820166
Ref: 3a0d11820166
Ref: library/xml dom module-xml dom11820166
Ref: 12111820166
Ref: library/xml dom translation-repo11820166
Ref: 3a0e11820166
Ref: library/xml dom xml-dom-the-document-object-model-api11820166
Ref: 3a0f11820166
Ref: xml dom — The Document Object Model API-Footnote-111823640
Ref: xml dom — The Document Object Model API-Footnote-211823717
Ref: xml dom — The Document Object Model API-Footnote-311823783
Ref: xml dom — The Document Object Model API-Footnote-411823830
Node: Module Contents<3>11823876
Ref: library/xml dom module-contents11823999
Ref: 3a1211823999
Ref: library/xml dom xml dom registerDOMImplementation11824103
Ref: 3a1311824103
Ref: library/xml dom xml dom getDOMImplementation11824551
Ref: 3a1011824551
Ref: library/xml dom xml dom EMPTY_NAMESPACE11825460
Ref: 3a1411825460
Ref: library/xml dom xml dom XML_NAMESPACE11825733
Ref: 3a1511825733
Ref: library/xml dom xml dom XMLNS_NAMESPACE11825890
Ref: 3a1611825890
Ref: library/xml dom xml dom XHTML_NAMESPACE11826076
Ref: 3a1711826076
Ref: Module Contents<3>-Footnote-111826805
Ref: Module Contents<3>-Footnote-211826850
Ref: Module Contents<3>-Footnote-311826907
Node: Objects in the DOM11826945
Ref: library/xml dom dom-objects11827088
Ref: 3a1811827088
Ref: library/xml dom objects-in-the-dom11827088
Ref: 3a1911827088
Node: DOMImplementation Objects11831623
Ref: library/xml dom dom-implementation-objects11831724
Ref: 3a1a11831724
Ref: library/xml dom domimplementation-objects11831724
Ref: 3a2311831724
Ref: library/xml dom xml dom DOMImplementation hasFeature11832080
Ref: 3a2411832080
Ref: library/xml dom xml dom DOMImplementation createDocument11832259
Ref: 3a2511832259
Ref: library/xml dom xml dom DOMImplementation createDocumentType11832779
Ref: 3a2611832779
Node: Node Objects11833087
Ref: library/xml dom dom-node-objects11833213
Ref: 3a1b11833213
Ref: library/xml dom node-objects11833213
Ref: 3a2711833213
Ref: library/xml dom xml dom Node nodeType11833330
Ref: 3a2811833330
Ref: library/xml dom xml dom Node parentNode11833753
Ref: 3a2911833753
Ref: library/xml dom xml dom Node attributes11834162
Ref: 3a2a11834162
Ref: library/xml dom xml dom Node previousSibling11834375
Ref: 3a2b11834375
Ref: library/xml dom xml dom Node nextSibling11834861
Ref: 3a2c11834861
Ref: library/xml dom xml dom Node childNodes11835127
Ref: 3a2d11835127
Ref: library/xml dom xml dom Node firstChild11835246
Ref: 3a2e11835246
Ref: library/xml dom xml dom Node lastChild11835383
Ref: 3a2f11835383
Ref: library/xml dom xml dom Node localName11835518
Ref: 3a3011835518
Ref: library/xml dom xml dom Node prefix11835682
Ref: 3a3111835682
Ref: library/xml dom xml dom Node namespaceURI11835850
Ref: 3a3211835850
Ref: library/xml dom xml dom Node nodeName11836013
Ref: 3a3311836013
Ref: library/xml dom xml dom Node nodeValue11836450
Ref: 3a3411836450
Ref: library/xml dom xml dom Node hasAttributes11836684
Ref: 3a3511836684
Ref: library/xml dom xml dom Node hasChildNodes11836775
Ref: 3a3611836775
Ref: library/xml dom xml dom Node isSameNode11836867
Ref: 3a3711836867
Ref: library/xml dom xml dom Node appendChild11837496
Ref: 3a3811837496
Ref: library/xml dom xml dom Node insertBefore11837704
Ref: 3a3911837704
Ref: library/xml dom xml dom Node removeChild11838045
Ref: 3a3a11838045
Ref: library/xml dom xml dom Node replaceChild11838333
Ref: 3a3b11838333
Ref: library/xml dom xml dom Node normalize11838547
Ref: 3a3c11838547
Ref: library/xml dom xml dom Node cloneNode11838764
Ref: 3a3d11838764
Node: NodeList Objects11838908
Ref: library/xml dom dom-nodelist-objects11839029
Ref: 211111839029
Ref: library/xml dom nodelist-objects11839029
Ref: 3a3e11839029
Ref: library/xml dom xml dom NodeList item11839510
Ref: 3a3f11839510
Ref: library/xml dom xml dom NodeList length11839740
Ref: 3a4011839740
Node: DocumentType Objects11840410
Ref: library/xml dom documenttype-objects11840535
Ref: 3a4111840535
Ref: library/xml dom dom-documenttype-objects11840535
Ref: 3a1c11840535
Ref: library/xml dom xml dom DocumentType publicId11841168
Ref: 3a4211841168
Ref: library/xml dom xml dom DocumentType systemId11841334
Ref: 3a4311841334
Ref: library/xml dom xml dom DocumentType internalSubset11841510
Ref: 3a4411841510
Ref: library/xml dom xml dom DocumentType name11841763
Ref: 3a4511841763
Ref: library/xml dom xml dom DocumentType entities11841892
Ref: 3a4611841892
Ref: library/xml dom xml dom DocumentType notations11842275
Ref: 3a4711842275
Node: Document Objects11842654
Ref: library/xml dom document-objects11842781
Ref: 3a4811842781
Ref: library/xml dom dom-document-objects11842781
Ref: 3a1d11842781
Ref: library/xml dom xml dom Document documentElement11843028
Ref: 15cb11843028
Ref: library/xml dom xml dom Document createElement11843122
Ref: 3a4911843122
Ref: library/xml dom xml dom Document createElementNS11843411
Ref: 3a4a11843411
Ref: library/xml dom xml dom Document createTextNode11843762
Ref: 3a4b11843762
Ref: library/xml dom xml dom Document createComment11843981
Ref: 3a4c11843981
Ref: library/xml dom xml dom Document createProcessingInstruction11844202
Ref: 3a4d11844202
Ref: library/xml dom xml dom Document createAttribute11844474
Ref: 3a4e11844474
Ref: library/xml dom xml dom Document createAttributeNS11844781
Ref: 3a4f11844781
Ref: library/xml dom xml dom Document getElementsByTagName11845169
Ref: 3a5011845169
Ref: library/xml dom xml dom Document getElementsByTagNameNS11845345
Ref: 3a5111845345
Node: Element Objects<2>11845616
Ref: library/xml dom dom-element-objects11845735
Ref: 3a1e11845735
Ref: library/xml dom element-objects11845735
Ref: 3a5211845735
Ref: library/xml dom xml dom Element tagName11845876
Ref: 3a5311845876
Ref: library/xml dom xml dom Element getElementsByTagName11846023
Ref: 3a5411846023
Ref: library/xml dom xml dom Element getElementsByTagNameNS11846136
Ref: 3a5511846136
Ref: library/xml dom xml dom Element hasAttribute11846267
Ref: 3a5611846267
Ref: library/xml dom xml dom Element hasAttributeNS11846381
Ref: 3a5711846381
Ref: library/xml dom xml dom Element getAttribute11846545
Ref: 3a5811846545
Ref: library/xml dom xml dom Element getAttributeNode11846758
Ref: 3a5911846758
Ref: library/xml dom xml dom Element getAttributeNS11846879
Ref: 3a5a11846879
Ref: library/xml dom xml dom Element getAttributeNodeNS11847137
Ref: 3a5b11847137
Ref: library/xml dom xml dom Element removeAttribute11847291
Ref: 3a5c11847291
Ref: library/xml dom xml dom Element removeAttributeNode11847449
Ref: 3a5e11847449
Ref: library/xml dom xml dom Element removeAttributeNS11847641
Ref: 3a5f11847641
Ref: library/xml dom xml dom Element setAttribute11847850
Ref: 3a6011847850
Ref: library/xml dom xml dom Element setAttributeNode11847942
Ref: 3a6111847942
Ref: library/xml dom xml dom Element setAttributeNodeNS11848286
Ref: 3a6311848286
Ref: library/xml dom xml dom Element setAttributeNS11848659
Ref: 3a6411848659
Node: Attr Objects11848895
Ref: library/xml dom attr-objects11849018
Ref: 3a6511849018
Ref: library/xml dom dom-attr-objects11849018
Ref: 3a1f11849018
Ref: library/xml dom xml dom Attr name11849133
Ref: 3a6611849133
Ref: library/xml dom xml dom Attr localName11849245
Ref: 3a6711849245
Ref: library/xml dom xml dom Attr prefix11849399
Ref: 3a6811849399
Ref: library/xml dom xml dom Attr value11849519
Ref: 3a6911849519
Node: NamedNodeMap Objects11849644
Ref: library/xml dom dom-attributelist-objects11849764
Ref: 3a6a11849764
Ref: library/xml dom namednodemap-objects11849764
Ref: 3a6b11849764
Ref: library/xml dom xml dom NamedNodeMap length11849883
Ref: 3a6c11849883
Ref: library/xml dom xml dom NamedNodeMap item11849959
Ref: 3a6d11849959
Node: Comment Objects11850440
Ref: library/xml dom comment-objects11850577
Ref: 3a6e11850577
Ref: library/xml dom dom-comment-objects11850577
Ref: 3a2011850577
Ref: library/xml dom xml dom Comment data11850749
Ref: 3a6f11850749
Node: Text and CDATASection Objects11850967
Ref: library/xml dom dom-text-objects11851113
Ref: 3a2111851113
Ref: library/xml dom text-and-cdatasection-objects11851113
Ref: 3a7011851113
Ref: library/xml dom xml dom Text data11851609
Ref: 3a7111851609
Node: ProcessingInstruction Objects11852102
Ref: library/xml dom dom-pi-objects11852247
Ref: 3a2211852247
Ref: library/xml dom processinginstruction-objects11852247
Ref: 3a7211852247
Ref: library/xml dom xml dom ProcessingInstruction target11852459
Ref: 3a7311852459
Ref: library/xml dom xml dom ProcessingInstruction data11852627
Ref: 3a7411852627
Node: Exceptions<20>11852765
Ref: library/xml dom dom-exceptions11852872
Ref: 3a7511852872
Ref: library/xml dom exceptions11852872
Ref: 3a7611852872
Ref: library/xml dom xml dom DOMException11853544
Ref: 3a7711853544
Ref: library/xml dom xml dom DomstringSizeErr11853706
Ref: 3a7811853706
Ref: library/xml dom xml dom HierarchyRequestErr11853961
Ref: 3a7911853961
Ref: library/xml dom xml dom IndexSizeErr11854100
Ref: 3a7a11854100
Ref: library/xml dom xml dom InuseAttributeErr11854242
Ref: 3a6211854242
Ref: library/xml dom xml dom InvalidAccessErr11854406
Ref: 3a7b11854406
Ref: library/xml dom xml dom InvalidCharacterErr11854539
Ref: 3a7c11854539
Ref: library/xml dom xml dom InvalidModificationErr11854899
Ref: 3a7d11854899
Ref: library/xml dom xml dom InvalidStateErr11855013
Ref: 3a7e11855013
Ref: library/xml dom xml dom NamespaceErr11855156
Ref: 3a7f11855156
Ref: library/xml dom xml dom NotFoundErr11855365
Ref: 3a5d11855365
Ref: library/xml dom xml dom NotSupportedErr11855596
Ref: 3a8011855596
Ref: library/xml dom xml dom NoDataAllowedErr11855738
Ref: 3a8111855738
Ref: library/xml dom xml dom NoModificationAllowedErr11855866
Ref: 3a8211855866
Ref: library/xml dom xml dom SyntaxErr11856032
Ref: 3a8311856032
Ref: library/xml dom xml dom WrongDocumentErr11856127
Ref: 3a8411856127
Ref: Exceptions<20>-Footnote-111859168
Node: Conformance11859213
Ref: library/xml dom conformance11859329
Ref: 3a8511859329
Ref: library/xml dom dom-conformance11859329
Ref: 3a1111859329
Node: Type Mapping11859586
Ref: library/xml dom dom-type-mapping11859671
Ref: 3a8611859671
Ref: library/xml dom type-mapping11859671
Ref: 3a8711859671
Node: Accessor Methods11860496
Ref: library/xml dom accessor-methods11860581
Ref: 3a8811860581
Ref: library/xml dom dom-accessor-methods11860581
Ref: 3a8911860581
Node: xml dom minidom — Minimal DOM implementation11862457
Ref: library/xml dom minidom doc11862691
Ref: 3a8a11862691
Ref: library/xml dom minidom module-xml dom minidom11862691
Ref: 12211862691
Ref: library/xml dom minidom translation-repo11862691
Ref: 3a8b11862691
Ref: library/xml dom minidom xml-dom-minidom-minimal-dom-implementation11862691
Ref: 3a8c11862691
Ref: library/xml dom minidom xml dom minidom parse11863912
Ref: 3a8d11863912
Ref: library/xml dom minidom xml dom minidom parseString11864481
Ref: 3a8e11864481
Ref: xml dom minidom — Minimal DOM implementation-Footnote-111867033
Ref: xml dom minidom — Minimal DOM implementation-Footnote-211867109
Node: DOM Objects11867156
Ref: library/xml dom minidom dom-objects11867270
Ref: 3a8f11867270
Ref: library/xml dom minidom minidom-objects11867270
Ref: 3a9011867270
Ref: library/xml dom minidom xml dom minidom Node unlink11867500
Ref: 3a9111867500
Ref: library/xml dom minidom xml dom minidom Node writexml11868276
Ref: aa711868276
Ref: library/xml dom minidom xml dom minidom Node toxml11869509
Ref: aa811869509
Ref: library/xml dom minidom xml dom minidom Node toprettyxml11870310
Ref: aa911870310
Ref: DOM Objects-Footnote-111871042
Node: DOM Example11871445
Ref: library/xml dom minidom dom-example11871596
Ref: 3a9211871596
Ref: library/xml dom minidom id211871596
Ref: 3a9311871596
Node: minidom and the DOM standard11873628
Ref: library/xml dom minidom minidom-and-dom11873759
Ref: 3a9411873759
Ref: library/xml dom minidom minidom-and-the-dom-standard11873759
Ref: 3a9511873759
Node: xml dom pulldom — Support for building partial DOM trees11876365
Ref: library/xml dom pulldom doc11876594
Ref: 3a9611876594
Ref: library/xml dom pulldom module-xml dom pulldom11876594
Ref: 12311876594
Ref: library/xml dom pulldom translation-repo11876594
Ref: 3a9711876594
Ref: library/xml dom pulldom xml-dom-pulldom-support-for-building-partial-dom-trees11876594
Ref: 3a9811876594
Ref: library/xml dom pulldom xml dom pulldom PullDOM11879232
Ref: 3a9a11879232
Ref: library/xml dom pulldom xml dom pulldom SAX2DOM11879353
Ref: 3a9c11879353
Ref: library/xml dom pulldom xml dom pulldom parse11879474
Ref: 3a9d11879474
Ref: library/xml dom pulldom xml dom pulldom parseString11880066
Ref: 3a9f11880066
Ref: library/xml dom pulldom xml dom pulldom default_bufsize11880218
Ref: 3aa011880218
Ref: xml dom pulldom — Support for building partial DOM trees-Footnote-111880531
Node: DOMEventStream Objects11880607
Ref: library/xml dom pulldom domeventstream-objects11880724
Ref: 3aa111880724
Ref: library/xml dom pulldom id111880724
Ref: 3aa211880724
Ref: library/xml dom pulldom xml dom pulldom DOMEventStream11880789
Ref: 73811880789
Ref: library/xml dom pulldom xml dom pulldom DOMEventStream getEvent11880957
Ref: 3aa311880957
Ref: library/xml dom pulldom xml dom pulldom DOMEventStream expandNode11881449
Ref: 3a9911881449
Ref: library/xml dom pulldom xml dom pulldom DOMEventStream reset11882163
Ref: 3aa411882163
Node: xml sax — Support for SAX2 parsers11882190
Ref: library/xml sax doc11882422
Ref: 3aa511882422
Ref: library/xml sax module-xml sax11882422
Ref: 12911882422
Ref: library/xml sax translation-repo11882422
Ref: 3aa611882422
Ref: library/xml sax xml-sax-support-for-sax2-parsers11882422
Ref: 3aa711882422
Ref: library/xml sax xml sax make_parser11883409
Ref: 1bcb11883409
Ref: library/xml sax xml sax parse11883907
Ref: 1b9411883907
Ref: library/xml sax xml sax parseString11884502
Ref: ed011884502
Ref: library/xml sax xml sax SAXException11886410
Ref: 3aac11886410
Ref: library/xml sax xml sax SAXParseException11887282
Ref: 3aaa11887282
Ref: library/xml sax xml sax SAXNotRecognizedException11887693
Ref: 3aad11887693
Ref: library/xml sax xml sax SAXNotSupportedException11887995
Ref: 3aae11887995
Ref: xml sax — Support for SAX2 parsers-Footnote-111889009
Ref: xml sax — Support for SAX2 parsers-Footnote-211889086
Node: SAXException Objects11889121
Ref: library/xml sax sax-exception-objects11889214
Ref: 3aaf11889214
Ref: library/xml sax saxexception-objects11889214
Ref: 3ab011889214
Ref: library/xml sax xml sax SAXException getMessage11889354
Ref: 3ab111889354
Ref: library/xml sax xml sax SAXException getException11889464
Ref: 3ab211889464
Node: xml sax handler — Base classes for SAX handlers11889568
Ref: library/xml sax handler doc11889776
Ref: 3ab311889776
Ref: library/xml sax handler module-xml sax handler11889776
Ref: 12a11889776
Ref: library/xml sax handler translation-repo11889776
Ref: 3ab411889776
Ref: library/xml sax handler xml-sax-handler-base-classes-for-sax-handlers11889776
Ref: 3ab511889776
Ref: library/xml sax handler xml sax handler ContentHandler11890474
Ref: 3a9b11890474
Ref: library/xml sax handler xml sax handler DTDHandler11890714
Ref: 3ab611890714
Ref: library/xml sax handler xml sax handler EntityResolver11890899
Ref: 3ab711890899
Ref: library/xml sax handler xml sax handler ErrorHandler11891181
Ref: 3aa911891181
Ref: library/xml sax handler xml sax handler LexicalHandler11891455
Ref: 86211891455
Ref: library/xml sax handler xml sax handler feature_namespaces11891740
Ref: 3ab811891740
Ref: library/xml sax handler xml sax handler feature_namespace_prefixes11892064
Ref: 3ab911892064
Ref: library/xml sax handler xml sax handler feature_string_interning11892493
Ref: 3aba11892493
Ref: library/xml sax handler xml sax handler feature_validation11892908
Ref: 3abb11892908
Ref: library/xml sax handler xml sax handler feature_external_ges11893247
Ref: 160411893247
Ref: library/xml sax handler xml sax handler feature_external_pes11893795
Ref: 3abc11893795
Ref: library/xml sax handler xml sax handler all_features11894176
Ref: 3abd11894176
Ref: library/xml sax handler xml sax handler property_lexical_handler11894244
Ref: 3abe11894244
Ref: library/xml sax handler xml sax handler property_declaration_handler11894564
Ref: 3abf11894564
Ref: library/xml sax handler xml sax handler property_dom_node11894922
Ref: 3ac011894922
Ref: library/xml sax handler xml sax handler property_xml_string11895312
Ref: 3ac111895312
Ref: library/xml sax handler xml sax handler all_properties11895580
Ref: 3ac211895580
Ref: xml sax handler — Base classes for SAX handlers-Footnote-111895837
Ref: xml sax handler — Base classes for SAX handlers-Footnote-211895913
Ref: xml sax handler — Base classes for SAX handlers-Footnote-311895978
Node: ContentHandler Objects11896029
Ref: library/xml sax handler content-handler-objects11896164
Ref: 3ac311896164
Ref: library/xml sax handler contenthandler-objects11896164
Ref: 3ac411896164
Ref: library/xml sax handler xml sax handler ContentHandler setDocumentLocator11896418
Ref: 3ac511896418
Ref: library/xml sax handler xml sax handler ContentHandler startDocument11897493
Ref: 3ac611897493
Ref: library/xml sax handler xml sax handler ContentHandler endDocument11897771
Ref: 3ac711897771
Ref: library/xml sax handler xml sax handler ContentHandler startPrefixMapping11898139
Ref: 3ac811898139
Ref: library/xml sax handler xml sax handler ContentHandler endPrefixMapping11899308
Ref: 3ac911899308
Ref: library/xml sax handler xml sax handler ContentHandler startElement11899644
Ref: 159311899644
Ref: library/xml sax handler xml sax handler ContentHandler endElement11900243
Ref: 159411900243
Ref: library/xml sax handler xml sax handler ContentHandler startElementNS11900471
Ref: 3acb11900471
Ref: library/xml sax handler xml sax handler ContentHandler endElementNS11901415
Ref: 3acd11901415
Ref: library/xml sax handler xml sax handler ContentHandler characters11901688
Ref: 159511901688
Ref: library/xml sax handler xml sax handler ContentHandler ignorableWhitespace11902715
Ref: 3ace11902715
Ref: library/xml sax handler xml sax handler ContentHandler processingInstruction11903382
Ref: 3acf11903382
Ref: library/xml sax handler xml sax handler ContentHandler skippedEntity11903842
Ref: 3ad011903842
Node: DTDHandler Objects11904342
Ref: library/xml sax handler dtd-handler-objects11904508
Ref: 3ad111904508
Ref: library/xml sax handler dtdhandler-objects11904508
Ref: 3ad211904508
Ref: library/xml sax handler xml sax handler DTDHandler notationDecl11904633
Ref: 3ad311904633
Ref: library/xml sax handler xml sax handler DTDHandler unparsedEntityDecl11904740
Ref: 3ad411904740
Node: EntityResolver Objects11904878
Ref: library/xml sax handler entity-resolver-objects11905042
Ref: 3ad511905042
Ref: library/xml sax handler entityresolver-objects11905042
Ref: 3ad611905042
Ref: library/xml sax handler xml sax handler EntityResolver resolveEntity11905109
Ref: 3ad711905109
Node: ErrorHandler Objects11905377
Ref: library/xml sax handler errorhandler-objects11905545
Ref: 3ad811905545
Ref: library/xml sax handler sax-error-handler11905545
Ref: 3ad911905545
Ref: library/xml sax handler xml sax handler ErrorHandler error11906193
Ref: 3ada11906193
Ref: library/xml sax handler xml sax handler ErrorHandler fatalError11906562
Ref: 3adb11906562
Ref: library/xml sax handler xml sax handler ErrorHandler warning11906748
Ref: 3adc11906748
Node: LexicalHandler Objects11907093
Ref: library/xml sax handler lexical-handler-objects11907230
Ref: 3add11907230
Ref: library/xml sax handler lexicalhandler-objects11907230
Ref: 3ade11907230
Ref: library/xml sax handler xml sax handler LexicalHandler comment11907835
Ref: 3adf11907835
Ref: library/xml sax handler xml sax handler LexicalHandler startDTD11907989
Ref: 3ae011907989
Ref: library/xml sax handler xml sax handler LexicalHandler endDTD11908147
Ref: 3ae111908147
Ref: library/xml sax handler xml sax handler LexicalHandler startCDATA11908227
Ref: 3ae211908227
Ref: library/xml sax handler xml sax handler LexicalHandler endCDATA11908421
Ref: 3ae311908421
Node: xml sax saxutils — SAX Utilities11908510
Ref: library/xml sax utils doc11908729
Ref: 3ae411908729
Ref: library/xml sax utils module-xml sax saxutils11908729
Ref: 12b11908729
Ref: library/xml sax utils translation-repo11908729
Ref: 3ae511908729
Ref: library/xml sax utils xml-sax-saxutils-sax-utilities11908729
Ref: 3ae611908729
Ref: library/xml sax utils xml sax saxutils escape11909110
Ref: 3ae711909110
Ref: library/xml sax utils xml sax saxutils unescape11909761
Ref: 3ae811909761
Ref: library/xml sax utils xml sax saxutils quoteattr11910229
Ref: 3ae911910229
Ref: library/xml sax utils xml sax saxutils XMLGenerator11911130
Ref: 3aea11911130
Ref: library/xml sax utils xml sax saxutils XMLFilterBase11911986
Ref: 3aeb11911986
Ref: library/xml sax utils xml sax saxutils prepare_input_source11912408
Ref: 3aec11912408
Ref: xml sax saxutils — SAX Utilities-Footnote-111912898
Node: xml sax xmlreader — Interface for XML parsers11912975
Ref: library/xml sax reader doc11913195
Ref: 3aee11913195
Ref: library/xml sax reader module-xml sax xmlreader11913195
Ref: 12c11913195
Ref: library/xml sax reader translation-repo11913195
Ref: 3aef11913195
Ref: library/xml sax reader xml-sax-xmlreader-interface-for-xml-parsers11913195
Ref: 3af011913195
Ref: library/xml sax reader xml sax xmlreader XMLReader11913695
Ref: 3a9e11913695
Ref: library/xml sax reader xml sax xmlreader IncrementalParser11913791
Ref: 3af111913791
Ref: library/xml sax reader xml sax xmlreader Locator11914918
Ref: 3aab11914918
Ref: library/xml sax reader xml sax xmlreader InputSource11915251
Ref: ecf11915251
Ref: library/xml sax reader xml sax xmlreader AttributesImpl11916002
Ref: 3af211916002
Ref: library/xml sax reader xml sax xmlreader AttributesNSImpl11916601
Ref: 3af311916601
Ref: xml sax xmlreader — Interface for XML parsers-Footnote-111917352
Node: XMLReader Objects11917430
Ref: library/xml sax reader id111917565
Ref: 3af411917565
Ref: library/xml sax reader xmlreader-objects11917565
Ref: 3af511917565
Ref: library/xml sax reader xml sax xmlreader XMLReader parse11917692
Ref: 3aed11917692
Ref: library/xml sax reader xml sax xmlreader XMLReader getContentHandler11918274
Ref: 3af611918274
Ref: library/xml sax reader xml sax xmlreader XMLReader setContentHandler11918371
Ref: 3af711918371
Ref: library/xml sax reader xml sax xmlreader XMLReader getDTDHandler11918547
Ref: 3af811918547
Ref: library/xml sax reader xml sax xmlreader XMLReader setDTDHandler11918636
Ref: 3af911918636
Ref: library/xml sax reader xml sax xmlreader XMLReader getEntityResolver11918796
Ref: 3afa11918796
Ref: library/xml sax reader xml sax xmlreader XMLReader setEntityResolver11918893
Ref: 3afb11918893
Ref: library/xml sax reader xml sax xmlreader XMLReader getErrorHandler11919178
Ref: 3afc11919178
Ref: library/xml sax reader xml sax xmlreader XMLReader setErrorHandler11919271
Ref: 3afd11919271
Ref: library/xml sax reader xml sax xmlreader XMLReader setLocale11919475
Ref: 3afe11919475
Ref: library/xml sax reader xml sax xmlreader XMLReader getFeature11919841
Ref: 3aff11919841
Ref: library/xml sax reader xml sax xmlreader XMLReader setFeature11920123
Ref: 3aa811920123
Ref: library/xml sax reader xml sax xmlreader XMLReader getProperty11920412
Ref: 3b0011920412
Ref: library/xml sax reader xml sax xmlreader XMLReader setProperty11920703
Ref: 3b0111920703
Node: IncrementalParser Objects11920997
Ref: library/xml sax reader incremental-parser-objects11921156
Ref: 3b0211921156
Ref: library/xml sax reader incrementalparser-objects11921156
Ref: 3b0311921156
Ref: library/xml sax reader xml sax xmlreader IncrementalParser feed11921314
Ref: 3b0411921314
Ref: library/xml sax reader xml sax xmlreader IncrementalParser close11921390
Ref: 3b0511921390
Ref: library/xml sax reader xml sax xmlreader IncrementalParser reset11921629
Ref: 3b0611921629
Node: Locator Objects11921891
Ref: library/xml sax reader id211922052
Ref: 3b0711922052
Ref: library/xml sax reader locator-objects11922052
Ref: 3b0811922052
Ref: library/xml sax reader xml sax xmlreader Locator getColumnNumber11922163
Ref: 3b0911922163
Ref: library/xml sax reader xml sax xmlreader Locator getLineNumber11922266
Ref: 3b0a11922266
Ref: library/xml sax reader xml sax xmlreader Locator getPublicId11922365
Ref: 3b0b11922365
Ref: library/xml sax reader xml sax xmlreader Locator getSystemId11922459
Ref: 3b0c11922459
Node: InputSource Objects11922553
Ref: library/xml sax reader input-source-objects11922713
Ref: 3b0d11922713
Ref: library/xml sax reader inputsource-objects11922713
Ref: 3b0e11922713
Ref: library/xml sax reader xml sax xmlreader InputSource setPublicId11922774
Ref: 3b0f11922774
Ref: library/xml sax reader xml sax xmlreader InputSource getPublicId11922881
Ref: 3b1011922881
Ref: library/xml sax reader xml sax xmlreader InputSource setSystemId11922989
Ref: 3b1111922989
Ref: library/xml sax reader xml sax xmlreader InputSource getSystemId11923096
Ref: 3b1211923096
Ref: library/xml sax reader xml sax xmlreader InputSource setEncoding11923204
Ref: 3b1311923204
Ref: library/xml sax reader xml sax xmlreader InputSource getEncoding11923584
Ref: 3b1411923584
Ref: library/xml sax reader xml sax xmlreader InputSource setByteStream11923678
Ref: 3b1511923678
Ref: library/xml sax reader xml sax xmlreader InputSource getByteStream11924111
Ref: 3b1611924111
Ref: library/xml sax reader xml sax xmlreader InputSource setCharacterStream11924319
Ref: 3b1711924319
Ref: library/xml sax reader xml sax xmlreader InputSource getCharacterStream11924633
Ref: 3b1811924633
Node: The Attributes Interface11924734
Ref: library/xml sax reader attributes-objects11924905
Ref: 3aca11924905
Ref: library/xml sax reader the-attributes-interface11924905
Ref: 3b1911924905
Ref: library/xml sax reader xml sax xmlreader Attributes getLength11925235
Ref: 3b1a11925235
Ref: library/xml sax reader xml sax xmlreader Attributes getNames11925311
Ref: 3b1b11925311
Ref: library/xml sax reader xml sax xmlreader Attributes getType11925389
Ref: 3b1c11925389
Ref: library/xml sax reader xml sax xmlreader Attributes getValue11925514
Ref: 3b1d11925514
Node: The AttributesNS Interface11925598
Ref: library/xml sax reader attributes-ns-objects11925741
Ref: 3acc11925741
Ref: library/xml sax reader the-attributesns-interface11925741
Ref: 3b1e11925741
Ref: library/xml sax reader xml sax xmlreader AttributesNS getValueByQName11926074
Ref: 3b1f11926074
Ref: library/xml sax reader xml sax xmlreader AttributesNS getNameByQName11926168
Ref: 3b2011926168
Ref: library/xml sax reader xml sax xmlreader AttributesNS getQNameByName11926291
Ref: 3b2111926291
Ref: library/xml sax reader xml sax xmlreader AttributesNS getQNames11926412
Ref: 3b2211926412
Node: xml parsers expat — Fast XML parsing using Expat11926503
Ref: library/pyexpat doc11926680
Ref: 3b2311926680
Ref: library/pyexpat module-xml parsers expat11926680
Ref: 12611926680
Ref: library/pyexpat translation-repo11926680
Ref: 3b2411926680
Ref: library/pyexpat xml-parsers-expat-fast-xml-parsing-using-expat11926680
Ref: 3b2511926680
Ref: library/pyexpat xml parsers expat ExpatError11927637
Ref: 12bf11927637
Ref: library/pyexpat xml parsers expat error11927847
Ref: 3b2711927847
Ref: library/pyexpat xml parsers expat XMLParserType11927927
Ref: 3b2811927927
Ref: library/pyexpat xml parsers expat ErrorString11928118
Ref: 3b2a11928118
Ref: library/pyexpat xml parsers expat ParserCreate11928241
Ref: 3b2911928241
Ref: library/pyexpat xmlparser-non-root11928771
Ref: 3b2b11928771
Ref: xml parsers expat — Fast XML parsing using Expat-Footnote-111930915
Ref: xml parsers expat — Fast XML parsing using Expat-Footnote-211931224
Node: XMLParser Objects<2>11931257
Ref: library/pyexpat id211931394
Ref: 3b2c11931394
Ref: library/pyexpat xmlparser-objects11931394
Ref: 15ff11931394
Ref: library/pyexpat xml parsers expat xmlparser Parse11931504
Ref: 3b2d11931504
Ref: library/pyexpat xml parsers expat xmlparser ParseFile11931882
Ref: 3b2e11931882
Ref: library/pyexpat xml parsers expat xmlparser SetBase11932102
Ref: 3b2f11932102
Ref: library/pyexpat xml parsers expat xmlparser GetBase11932518
Ref: 3b3311932518
Ref: library/pyexpat xml parsers expat xmlparser GetInputContext11932704
Ref: 3b3411932704
Ref: library/pyexpat xml parsers expat xmlparser ExternalEntityParserCreate11932987
Ref: 15b011932987
Ref: library/pyexpat xml parsers expat xmlparser SetParamEntityParsing11933504
Ref: 3b3711933504
Ref: library/pyexpat xml parsers expat xmlparser UseForeignDTD11933869
Ref: 3b3811933869
Ref: library/pyexpat xml parsers expat xmlparser SetReparseDeferralEnabled11934849
Ref: 27211934849
Ref: library/pyexpat xml parsers expat xmlparser GetReparseDeferralEnabled11936351
Ref: 27111936351
Ref: library/pyexpat xml parsers expat xmlparser SetAllocTrackerActivationThreshold11936631
Ref: 15fd11936631
Ref: library/pyexpat xml parsers expat xmlparser SetAllocTrackerMaximumAmplification11937227
Ref: 15fe11937227
Ref: library/pyexpat xml parsers expat xmlparser buffer_size11938692
Ref: 3b3d11938692
Ref: library/pyexpat xml parsers expat xmlparser buffer_text11938954
Ref: 151111938954
Ref: library/pyexpat xml parsers expat xmlparser buffer_used11939500
Ref: 3b3f11939500
Ref: library/pyexpat xml parsers expat xmlparser ordered_attributes11939766
Ref: 3b3511939766
Ref: library/pyexpat xml parsers expat xmlparser specified_attributes11940258
Ref: 3b3611940258
Ref: library/pyexpat xml parsers expat xmlparser ErrorByteIndex11941065
Ref: 3b4011941065
Ref: library/pyexpat xml parsers expat xmlparser ErrorCode11941151
Ref: 3b4111941151
Ref: library/pyexpat xml parsers expat xmlparser ErrorColumnNumber11941382
Ref: 3b4211941382
Ref: library/pyexpat xml parsers expat xmlparser ErrorLineNumber11941474
Ref: 3b4311941474
Ref: library/pyexpat xml parsers expat xmlparser CurrentByteIndex11941967
Ref: 3b4411941967
Ref: library/pyexpat xml parsers expat xmlparser CurrentColumnNumber11942056
Ref: 3b4511942056
Ref: library/pyexpat xml parsers expat xmlparser CurrentLineNumber11942151
Ref: 3b4611942151
Ref: library/pyexpat xml parsers expat xmlparser XmlDeclHandler11942564
Ref: 3b4711942564
Ref: library/pyexpat xml parsers expat xmlparser StartDoctypeDeclHandler11943177
Ref: 3b3911943177
Ref: library/pyexpat xml parsers expat xmlparser EndDoctypeDeclHandler11943729
Ref: 3b3a11943729
Ref: library/pyexpat xml parsers expat xmlparser ElementDeclHandler11943895
Ref: 15a511943895
Ref: library/pyexpat xml parsers expat xmlparser AttlistDeclHandler11944109
Ref: 3b4811944109
Ref: library/pyexpat xml parsers expat xmlparser StartElementHandler11945012
Ref: 3b4911945012
Ref: library/pyexpat xml parsers expat xmlparser EndElementHandler11945403
Ref: 3b4a11945403
Ref: library/pyexpat xml parsers expat xmlparser ProcessingInstructionHandler11945494
Ref: 3b4b11945494
Ref: library/pyexpat xml parsers expat xmlparser CharacterDataHandler11945608
Ref: 3b3e11945608
Ref: library/pyexpat xml parsers expat xmlparser UnparsedEntityDeclHandler11946267
Ref: 3b3211946267
Ref: library/pyexpat xml parsers expat xmlparser EntityDeclHandler11946660
Ref: 3b4e11946660
Ref: library/pyexpat xml parsers expat xmlparser NotationDeclHandler11947405
Ref: 3b3111947405
Ref: library/pyexpat xml parsers expat xmlparser StartNamespaceDeclHandler11947696
Ref: 3b4f11947696
Ref: library/pyexpat xml parsers expat xmlparser EndNamespaceDeclHandler11947974
Ref: 3b5011947974
Ref: library/pyexpat xml parsers expat xmlparser CommentHandler11948497
Ref: 3b5111948497
Ref: library/pyexpat xml parsers expat xmlparser StartCdataSectionHandler11948683
Ref: 3b4c11948683
Ref: library/pyexpat xml parsers expat xmlparser EndCdataSectionHandler11948920
Ref: 3b4d11948920
Ref: library/pyexpat xml parsers expat xmlparser DefaultHandler11949013
Ref: 3b5211949013
Ref: library/pyexpat xml parsers expat xmlparser DefaultHandlerExpand11949298
Ref: 3b5311949298
Ref: library/pyexpat xml parsers expat xmlparser NotStandaloneHandler11949538
Ref: 3b5411949538
Ref: library/pyexpat xml parsers expat xmlparser ExternalEntityRefHandler11950060
Ref: 3b3011950060
Ref: XMLParser Objects<2>-Footnote-111951470
Ref: XMLParser Objects<2>-Footnote-211951535
Node: ExpatError Exceptions11951586
Ref: library/pyexpat expaterror-exceptions11951743
Ref: 3b5511951743
Ref: library/pyexpat expaterror-objects11951743
Ref: 3b2611951743
Ref: library/pyexpat xml parsers expat ExpatError code11951885
Ref: 3b5611951885
Ref: library/pyexpat xml parsers expat ExpatError lineno11952534
Ref: 3b3b11952534
Ref: library/pyexpat xml parsers expat ExpatError offset11952661
Ref: 3b3c11952661
Node: Example<10>11952802
Ref: library/pyexpat example11952965
Ref: 3b5911952965
Ref: library/pyexpat expat-example11952965
Ref: 3b5a11952965
Node: Content Model Descriptions11954063
Ref: library/pyexpat content-model-descriptions11954226
Ref: 3b5b11954226
Ref: library/pyexpat expat-content-models11954226
Ref: 3b5c11954226
Ref: library/pyexpat module-xml parsers expat model11954226
Ref: 12811954226
Node: Expat error constants11956063
Ref: library/pyexpat expat-error-constants11956206
Ref: 3b5d11956206
Ref: library/pyexpat expat-errors11956206
Ref: 3b5e11956206
Ref: library/pyexpat module-xml parsers expat errors11956206
Ref: 12711956206
Ref: library/pyexpat xml parsers expat errors codes11956790
Ref: 3b5811956790
Ref: library/pyexpat xml parsers expat errors messages11956929
Ref: 3b5711956929
Ref: library/pyexpat xml parsers expat errors XML_ERROR_ASYNC_ENTITY11957084
Ref: 3b5f11957084
Ref: library/pyexpat xml parsers expat errors XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF11957143
Ref: 3b6011957143
Ref: library/pyexpat xml parsers expat errors XML_ERROR_BAD_CHAR_REF11957344
Ref: 3b6111957344
Ref: library/pyexpat xml parsers expat errors XML_ERROR_BINARY_ENTITY_REF11957539
Ref: 3b6211957539
Ref: library/pyexpat xml parsers expat errors XML_ERROR_DUPLICATE_ATTRIBUTE11957713
Ref: 3b6311957713
Ref: library/pyexpat xml parsers expat errors XML_ERROR_INCORRECT_ENCODING11957838
Ref: 3b6411957838
Ref: library/pyexpat xml parsers expat errors XML_ERROR_INVALID_TOKEN11957903
Ref: 3b6511957903
Ref: library/pyexpat xml parsers expat errors XML_ERROR_JUNK_AFTER_DOC_ELEMENT11958117
Ref: 3b6611958117
Ref: library/pyexpat xml parsers expat errors XML_ERROR_MISPLACED_XML_PI11958266
Ref: 3b6711958266
Ref: library/pyexpat xml parsers expat errors XML_ERROR_NO_ELEMENTS11958419
Ref: 3b6811958419
Ref: library/pyexpat xml parsers expat errors XML_ERROR_NO_MEMORY11958594
Ref: 3b6911958594
Ref: library/pyexpat xml parsers expat errors XML_ERROR_PARAM_ENTITY_REF11958706
Ref: 3b6a11958706
Ref: library/pyexpat xml parsers expat errors XML_ERROR_PARTIAL_CHAR11958840
Ref: 3b6b11958840
Ref: library/pyexpat xml parsers expat errors XML_ERROR_RECURSIVE_ENTITY_REF11958953
Ref: 3b6c11958953
Ref: library/pyexpat xml parsers expat errors XML_ERROR_SYNTAX11959155
Ref: 3b6d11959155
Ref: library/pyexpat xml parsers expat errors XML_ERROR_TAG_MISMATCH11959261
Ref: 3b6e11959261
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNCLOSED_TOKEN11959381
Ref: 3b6f11959381
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNDEFINED_ENTITY11959565
Ref: 3b7011959565
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNKNOWN_ENCODING11959691
Ref: 3b7111959691
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNCLOSED_CDATA_SECTION11959809
Ref: 3b7211959809
Ref: library/pyexpat xml parsers expat errors XML_ERROR_EXTERNAL_ENTITY_HANDLING11959923
Ref: 3b7311959923
Ref: library/pyexpat xml parsers expat errors XML_ERROR_NOT_STANDALONE11959994
Ref: 3b7411959994
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNEXPECTED_STATE11960257
Ref: 3b7511960257
Ref: library/pyexpat xml parsers expat errors XML_ERROR_ENTITY_DECLARED_IN_PE11960320
Ref: 3b7611960320
Ref: library/pyexpat xml parsers expat errors XML_ERROR_FEATURE_REQUIRES_XML_DTD11960388
Ref: 3b7711960388
Ref: library/pyexpat xml parsers expat errors XML_ERROR_CANT_CHANGE_FEATURE_ONCE_PARSING11960688
Ref: 3b7811960688
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNBOUND_PREFIX11960961
Ref: 3b7911960961
Ref: library/pyexpat xml parsers expat errors XML_ERROR_UNDECLARING_PREFIX11961103
Ref: 3b7a11961103
Ref: library/pyexpat xml parsers expat errors XML_ERROR_INCOMPLETE_PE11961264
Ref: 3b7b11961264
Ref: library/pyexpat xml parsers expat errors XML_ERROR_XML_DECL11961378
Ref: 3b7c11961378
Ref: library/pyexpat xml parsers expat errors XML_ERROR_TEXT_DECL11961490
Ref: 3b7d11961490
Ref: library/pyexpat xml parsers expat errors XML_ERROR_PUBLICID11961626
Ref: 3b7e11961626
Ref: library/pyexpat xml parsers expat errors XML_ERROR_SUSPENDED11961748
Ref: 3b7f11961748
Ref: library/pyexpat xml parsers expat errors XML_ERROR_NOT_SUSPENDED11961972
Ref: 3b8011961972
Ref: library/pyexpat xml parsers expat errors XML_ERROR_ABORTED11962124
Ref: 3b8111962124
Ref: library/pyexpat xml parsers expat errors XML_ERROR_FINISHED11962236
Ref: 3b8211962236
Ref: library/pyexpat xml parsers expat errors XML_ERROR_SUSPEND_PE11962482
Ref: 3b8311962482
Ref: library/pyexpat xml parsers expat errors XML_ERROR_RESERVED_PREFIX_XML11962539
Ref: 3b8411962539
Ref: library/pyexpat xml parsers expat errors XML_ERROR_RESERVED_PREFIX_XMLNS11962725
Ref: 3b8511962725
Ref: library/pyexpat xml parsers expat errors XML_ERROR_RESERVED_NAMESPACE_URI11962887
Ref: 3b8611962887
Ref: library/pyexpat xml parsers expat errors XML_ERROR_INVALID_ARGUMENT11963097
Ref: 3b8711963097
Ref: library/pyexpat xml parsers expat errors XML_ERROR_NO_BUFFER11963218
Ref: 3b8811963218
Ref: library/pyexpat xml parsers expat errors XML_ERROR_AMPLIFICATION_LIMIT_BREACH11963332
Ref: 3b8911963332
Node: Internet Protocols and Support11963499
Ref: library/internet doc11963664
Ref: 3b8a11963664
Ref: library/internet internet11963664
Ref: 3b8b11963664
Ref: library/internet internet-protocols-and-support11963664
Ref: 3b8c11963664
Ref: library/internet translation-repo11963664
Ref: 3b8d11963664
Node: webbrowser — Convenient web-browser controller11965607
Ref: library/webbrowser doc11965786
Ref: 3b8e11965786
Ref: library/webbrowser module-webbrowser11965786
Ref: 11511965786
Ref: library/webbrowser webbrowser-convenient-web-browser-controller11965786
Ref: 3b8f11965786
Ref: webbrowser — Convenient web-browser controller-Footnote-111967875
Ref: webbrowser — Convenient web-browser controller-Footnote-211967945
Node: Command-line interface<4>11968078
Ref: library/webbrowser command-line-interface11968223
Ref: 3b9011968223
Ref: library/webbrowser webbrowser-cli11968223
Ref: 3b9111968223
Ref: library/webbrowser cmdoption-webbrowser-n11968455
Ref: 3b9211968455
Ref: library/webbrowser cmdoption-webbrowser-new-window11968455
Ref: 3b9311968455
Ref: library/webbrowser cmdoption-webbrowser-t11968543
Ref: 3b9411968543
Ref: library/webbrowser cmdoption-webbrowser-new-tab11968543
Ref: 3b9511968543
Ref: library/webbrowser webbrowser Error11968820
Ref: 3b9611968820
Ref: library/webbrowser webbrowser open11968951
Ref: 15a811968951
Ref: library/webbrowser webbrowser open_new11969852
Ref: 3b9711969852
Ref: library/webbrowser webbrowser open_new_tab11970111
Ref: 3b9811970111
Ref: library/webbrowser webbrowser get11970382
Ref: 3b9911970382
Ref: library/webbrowser webbrowser register11970610
Ref: 3b9a11970610
Node: Browser controller objects11976951
Ref: library/webbrowser browser-controller-objects11977096
Ref: 3b9b11977096
Ref: library/webbrowser browser-controllers11977096
Ref: 3b9c11977096
Ref: library/webbrowser webbrowser controller name11977313
Ref: 29711977313
Ref: library/webbrowser webbrowser controller open11977390
Ref: 3b9d11977390
Ref: library/webbrowser webbrowser controller open_new11977654
Ref: 3b9e11977654
Ref: library/webbrowser webbrowser controller open_new_tab11977873
Ref: 3b9f11977873
Node: wsgiref — WSGI Utilities and Reference Implementation11978073
Ref: library/wsgiref doc11978292
Ref: 3ba011978292
Ref: library/wsgiref module-wsgiref11978292
Ref: 11811978292
Ref: library/wsgiref translation-repo11978292
Ref: 3ba111978292
Ref: library/wsgiref wsgiref-wsgi-utilities-and-reference-implementation11978292
Ref: 3ba211978292
Ref: wsgiref — WSGI Utilities and Reference Implementation-Footnote-111980465
Ref: wsgiref — WSGI Utilities and Reference Implementation-Footnote-211980529
Ref: wsgiref — WSGI Utilities and Reference Implementation-Footnote-311980571
Node: wsgiref util – WSGI environment utilities11980608
Ref: library/wsgiref module-wsgiref util11980798
Ref: 11d11980798
Ref: library/wsgiref wsgiref-util-wsgi-environment-utilities11980798
Ref: 3ba311980798
Ref: library/wsgiref wsgiref util guess_scheme11981342
Ref: 3ba511981342
Ref: library/wsgiref wsgiref util request_uri11981994
Ref: 3ba611981994
Ref: library/wsgiref wsgiref util application_uri11982320
Ref: 3ba711982320
Ref: library/wsgiref wsgiref util shift_path_info11982586
Ref: 3ba811982586
Ref: library/wsgiref wsgiref util setup_testing_defaults11984247
Ref: 3ba911984247
Ref: library/wsgiref wsgiref util is_hop_by_hop11985985
Ref: 17d411985985
Ref: library/wsgiref wsgiref util FileWrapper11986158
Ref: 73911986158
Ref: wsgiref util – WSGI environment utilities-Footnote-111987401
Ref: wsgiref util – WSGI environment utilities-Footnote-211987443
Ref: wsgiref util – WSGI environment utilities-Footnote-311987485
Ref: wsgiref util – WSGI environment utilities-Footnote-411987527
Ref: wsgiref util – WSGI environment utilities-Footnote-511987569
Node: wsgiref headers – WSGI response header tools11987628
Ref: library/wsgiref module-wsgiref headers11987878
Ref: 11a11987878
Ref: library/wsgiref wsgiref-headers-wsgi-response-header-tools11987878
Ref: 3bac11987878
Ref: library/wsgiref wsgiref headers Headers11988140
Ref: ecc11988140
Ref: library/wsgiref wsgiref headers Headers get_all11990378
Ref: 3bad11990378
Ref: library/wsgiref wsgiref headers Headers add_header11990815
Ref: 3bae11990815
Ref: wsgiref headers – WSGI response header tools-Footnote-111991952
Node: wsgiref simple_server – a simple WSGI HTTP server11991994
Ref: library/wsgiref module-wsgiref simple_server11992246
Ref: 11b11992246
Ref: library/wsgiref wsgiref-simple-server-a-simple-wsgi-http-server11992246
Ref: 3baf11992246
Ref: library/wsgiref wsgiref simple_server make_server11992840
Ref: 3bb011992840
Ref: library/wsgiref wsgiref simple_server demo_app11993680
Ref: 3baa11993680
Ref: library/wsgiref wsgiref simple_server WSGIServer11994205
Ref: 3bb211994205
Ref: library/wsgiref wsgiref simple_server WSGIServer set_app11994938
Ref: 3bb411994938
Ref: library/wsgiref wsgiref simple_server WSGIServer get_app11995083
Ref: 3bb511995083
Ref: library/wsgiref wsgiref simple_server WSGIRequestHandler11995426
Ref: 3bb611995426
Ref: library/wsgiref wsgiref simple_server WSGIRequestHandler get_environ11996042
Ref: 3bb711996042
Ref: library/wsgiref wsgiref simple_server WSGIRequestHandler get_stderr11996544
Ref: 3bb811996544
Ref: library/wsgiref wsgiref simple_server WSGIRequestHandler handle11996727
Ref: 3bb911996727
Ref: wsgiref simple_server – a simple WSGI HTTP server-Footnote-111996998
Ref: wsgiref simple_server – a simple WSGI HTTP server-Footnote-211997040
Node: wsgiref validate — WSGI conformance checker11997082
Ref: library/wsgiref module-wsgiref validate11997336
Ref: 11e11997336
Ref: library/wsgiref wsgiref-validate-wsgi-conformance-checker11997336
Ref: 3bba11997336
Ref: library/wsgiref wsgiref validate validator11998238
Ref: 3bbb11998238
Ref: wsgiref validate — WSGI conformance checker-Footnote-112000445
Ref: wsgiref validate — WSGI conformance checker-Footnote-212000487
Ref: wsgiref validate — WSGI conformance checker-Footnote-312000546
Node: wsgiref handlers – server/gateway base classes12000588
Ref: library/wsgiref module-wsgiref handlers12000844
Ref: 11912000844
Ref: library/wsgiref wsgiref-handlers-server-gateway-base-classes12000844
Ref: 3bbc12000844
Ref: library/wsgiref wsgiref handlers CGIHandler12001235
Ref: 3bbd12001235
Ref: library/wsgiref wsgiref handlers IISCGIHandler12001884
Ref: 3bbf12001884
Ref: library/wsgiref wsgiref handlers BaseCGIHandler12003261
Ref: 3bbe12003261
Ref: library/wsgiref wsgiref handlers SimpleHandler12004117
Ref: 3bc012004117
Ref: library/wsgiref wsgiref handlers BaseHandler12005060
Ref: 1b8012005060
Ref: library/wsgiref wsgiref handlers BaseHandler run12005412
Ref: 3bc612005412
Ref: library/wsgiref wsgiref handlers BaseHandler _write12005744
Ref: 3bc412005744
Ref: library/wsgiref wsgiref handlers BaseHandler _flush12006083
Ref: 3bc512006083
Ref: library/wsgiref wsgiref handlers BaseHandler get_stdin12006292
Ref: 3bc112006292
Ref: library/wsgiref wsgiref handlers BaseHandler get_stderr12006495
Ref: 3bc212006495
Ref: library/wsgiref wsgiref handlers BaseHandler add_cgi_vars12006700
Ref: 3bc312006700
Ref: library/wsgiref wsgiref handlers BaseHandler wsgi_multithread12007240
Ref: 3bc912007240
Ref: library/wsgiref wsgiref handlers BaseHandler wsgi_multiprocess12007525
Ref: 3bca12007525
Ref: library/wsgiref wsgiref handlers BaseHandler wsgi_run_once12007812
Ref: 3bcb12007812
Ref: library/wsgiref wsgiref handlers BaseHandler os_environ12008049
Ref: 3bcc12008049
Ref: library/wsgiref wsgiref handlers BaseHandler server_software12008549
Ref: 3bcd12008549
Ref: library/wsgiref wsgiref handlers BaseHandler get_scheme12009145
Ref: 3bcf12009145
Ref: library/wsgiref wsgiref handlers BaseHandler setup_environ12009506
Ref: 3bd012009506
Ref: library/wsgiref wsgiref handlers BaseHandler log_exception12010166
Ref: 3bd212010166
Ref: library/wsgiref wsgiref handlers BaseHandler traceback_limit12010666
Ref: 3bd312010666
Ref: library/wsgiref wsgiref handlers BaseHandler error_output12010888
Ref: 3bd412010888
Ref: library/wsgiref wsgiref handlers BaseHandler error_status12012070
Ref: 3bd512012070
Ref: library/wsgiref wsgiref handlers BaseHandler error_headers12012275
Ref: 3bd612012275
Ref: library/wsgiref wsgiref handlers BaseHandler error_body12012567
Ref: 3bd712012567
Ref: library/wsgiref wsgiref handlers BaseHandler wsgi_file_wrapper12012913
Ref: 3bd112012913
Ref: library/wsgiref wsgiref handlers BaseHandler sendfile12013186
Ref: 3bd812013186
Ref: library/wsgiref wsgiref handlers BaseHandler origin_server12013762
Ref: 3bce12013762
Ref: library/wsgiref wsgiref handlers BaseHandler http_version12014283
Ref: 3bd912014283
Ref: library/wsgiref wsgiref handlers read_environ12014505
Ref: 11fd12014505
Ref: wsgiref handlers – server/gateway base classes-Footnote-112015421
Ref: wsgiref handlers – server/gateway base classes-Footnote-212015463
Ref: wsgiref handlers – server/gateway base classes-Footnote-312015505
Ref: wsgiref handlers – server/gateway base classes-Footnote-412015547
Ref: wsgiref handlers – server/gateway base classes-Footnote-512015589
Node: wsgiref types – WSGI types for static type checking12015631
Ref: library/wsgiref module-wsgiref types12015854
Ref: 11c12015854
Ref: library/wsgiref wsgiref-types-wsgi-types-for-static-type-checking12015854
Ref: 3bda12015854
Ref: library/wsgiref wsgiref types StartResponse12016101
Ref: 3bb112016101
Ref: library/wsgiref wsgiref types WSGIEnvironment12016239
Ref: 3ba412016239
Ref: library/wsgiref wsgiref types WSGIApplication12016341
Ref: 3bdb12016341
Ref: library/wsgiref wsgiref types InputStream12016441
Ref: 3bc712016441
Ref: library/wsgiref wsgiref types ErrorStream12016550
Ref: 3bc812016550
Ref: library/wsgiref wsgiref types FileWrapper12016659
Ref: 3bab12016659
Ref: wsgiref types – WSGI types for static type checking-Footnote-112016899
Ref: wsgiref types – WSGI types for static type checking-Footnote-212016941
Ref: wsgiref types – WSGI types for static type checking-Footnote-312017011
Ref: wsgiref types – WSGI types for static type checking-Footnote-412017053
Ref: wsgiref types – WSGI types for static type checking-Footnote-512017119
Ref: wsgiref types – WSGI types for static type checking-Footnote-612017185
Node: Examples<25>12017269
Ref: library/wsgiref examples12017435
Ref: 3bdc12017435
Node: urllib — URL handling modules12020267
Ref: library/urllib doc12020492
Ref: 3bdd12020492
Ref: library/urllib module-urllib12020492
Ref: 10812020492
Ref: library/urllib translation-repo12020492
Ref: 3bde12020492
Ref: library/urllib urllib-url-handling-modules12020492
Ref: 3bdf12020492
Ref: urllib — URL handling modules-Footnote-112021073
Node: urllib request — Extensible library for opening URLs12021137
Ref: library/urllib request doc12021358
Ref: 3be012021358
Ref: library/urllib request module-urllib request12021358
Ref: 10b12021358
Ref: library/urllib request translation-repo12021358
Ref: 3be112021358
Ref: library/urllib request urllib-request-extensible-library-for-opening-urls12021358
Ref: 3be212021358
Ref: library/urllib request urllib request urlopen12022451
Ref: 29312022451
Ref: library/urllib request urllib request install_opener12026053
Ref: 3be912026053
Ref: library/urllib request urllib request build_opener12026501
Ref: 3bea12026501
Ref: library/urllib request urllib request pathname2url12027612
Ref: 169b12027612
Ref: library/urllib request urllib request url2pathname12028115
Ref: 169c12028115
Ref: library/urllib request urllib request getproxies12028625
Ref: 3be312028625
Ref: library/urllib request urllib request Request12029768
Ref: 101312029768
Ref: library/urllib request urllib request OpenerDirector12034261
Ref: 3be712034261
Ref: library/urllib request urllib request BaseHandler12034473
Ref: 3beb12034473
Ref: library/urllib request urllib request HTTPDefaultErrorHandler12034633
Ref: 3bec12034633
Ref: library/urllib request urllib request HTTPRedirectHandler12034826
Ref: 3bed12034826
Ref: library/urllib request urllib request HTTPCookieProcessor12034911
Ref: 3bf212034911
Ref: library/urllib request urllib request ProxyHandler12035013
Ref: 1b6012035013
Ref: library/urllib request urllib request HTTPPasswordMgr12036102
Ref: 3bf312036102
Ref: library/urllib request urllib request HTTPPasswordMgrWithDefaultRealm12036219
Ref: 3bf412036219
Ref: library/urllib request urllib request HTTPPasswordMgrWithPriorAuth12036460
Ref: ec812036460
Ref: library/urllib request urllib request AbstractBasicAuthHandler12036848
Ref: 1a1612036848
Ref: library/urllib request urllib request HTTPBasicAuthHandler12038192
Ref: 3bf712038192
Ref: library/urllib request urllib request ProxyBasicAuthHandler12038656
Ref: 3bf812038656
Ref: library/urllib request urllib request AbstractDigestAuthHandler12038996
Ref: 1b1412038996
Ref: library/urllib request urllib request HTTPDigestAuthHandler12039406
Ref: 3bf912039406
Ref: library/urllib request urllib request ProxyDigestAuthHandler12040268
Ref: 3bfa12040268
Ref: library/urllib request urllib request HTTPHandler12040609
Ref: d2312040609
Ref: library/urllib request urllib request HTTPSHandler12040694
Ref: 126912040694
Ref: library/urllib request urllib request FileHandler12041024
Ref: 3bef12041024
Ref: library/urllib request urllib request DataHandler12041087
Ref: 101212041087
Ref: library/urllib request urllib request FTPHandler12041176
Ref: 3bee12041176
Ref: library/urllib request urllib request CacheFTPHandler12041235
Ref: 183912041235
Ref: library/urllib request urllib request UnknownHandler12041364
Ref: 3be812041364
Ref: library/urllib request urllib request HTTPErrorProcessor12041454
Ref: 3bf012041454
Ref: urllib request — Extensible library for opening URLs-Footnote-112042335
Ref: urllib request — Extensible library for opening URLs-Footnote-212042409
Ref: urllib request — Extensible library for opening URLs-Footnote-312042460
Ref: urllib request — Extensible library for opening URLs-Footnote-412042519
Ref: urllib request — Extensible library for opening URLs-Footnote-512042578
Node: Request Objects12042637
Ref: library/urllib request id112042774
Ref: 3bfb12042774
Ref: library/urllib request request-objects12042774
Ref: 3bfc12042774
Ref: library/urllib request urllib request Request full_url12043046
Ref: 101512043046
Ref: library/urllib request urllib request Request type12043335
Ref: 3bfd12043335
Ref: library/urllib request urllib request Request host12043386
Ref: 3bfe12043386
Ref: library/urllib request urllib request Request origin_req_host12043513
Ref: 3bff12043513
Ref: library/urllib request urllib request Request selector12043608
Ref: 3c0012043608
Ref: library/urllib request urllib request Request data12043773
Ref: 101612043773
Ref: library/urllib request urllib request Request unverifiable12044030
Ref: 3c0112044030
Ref: library/urllib request urllib request Request method12044160
Ref: 101412044160
Ref: library/urllib request urllib request Request get_method12044853
Ref: 11ad12044853
Ref: library/urllib request urllib request Request add_header12045278
Ref: 3bf112045278
Ref: library/urllib request urllib request Request add_unredirected_header12045958
Ref: 3c0212045958
Ref: library/urllib request urllib request Request has_header12046084
Ref: 3c0312046084
Ref: library/urllib request urllib request Request remove_header12046225
Ref: 101812046225
Ref: library/urllib request urllib request Request get_full_url12046400
Ref: 3c0412046400
Ref: library/urllib request urllib request Request set_proxy12046558
Ref: 3c0512046558
Ref: library/urllib request urllib request Request get_header12046811
Ref: 3c0612046811
Ref: library/urllib request urllib request Request header_items12046977
Ref: 3c0712046977
Ref: Request Objects-Footnote-112047336
Node: OpenerDirector Objects12047395
Ref: library/urllib request opener-director-objects12047560
Ref: 3c0812047560
Ref: library/urllib request openerdirector-objects12047560
Ref: 3c0912047560
Ref: library/urllib request urllib request OpenerDirector add_handler12047692
Ref: 3c0a12047692
Ref: library/urllib request urllib request OpenerDirector open12049250
Ref: 101712049250
Ref: library/urllib request urllib request OpenerDirector error12049927
Ref: 3c0f12049927
Node: BaseHandler Objects12051712
Ref: library/urllib request base-handler-objects12051889
Ref: 3c1212051889
Ref: library/urllib request basehandler-objects12051889
Ref: 3c1312051889
Ref: library/urllib request urllib request BaseHandler add_parent12052129
Ref: 3c1412052129
Ref: library/urllib request urllib request BaseHandler close12052208
Ref: 3c1512052208
Ref: library/urllib request urllib request BaseHandler parent12052584
Ref: 3c1612052584
Ref: library/urllib request urllib request BaseHandler default_open12052738
Ref: 3c1012052738
Ref: library/urllib request protocol-open12053415
Ref: 3c0b12053415
Ref: library/urllib request urllib request BaseHandler unknown_open12053786
Ref: 3c1112053786
Ref: library/urllib request urllib request BaseHandler http_error_default12054198
Ref: 3c1712054198
Ref: library/urllib request http-error-nnn12055084
Ref: 3c0c12055084
Ref: library/urllib request protocol-request12055588
Ref: 3c0d12055588
Ref: library/urllib request protocol-response12055997
Ref: 3c0e12055997
Node: HTTPRedirectHandler Objects12056578
Ref: library/urllib request http-redirect-handler12056760
Ref: 3c1812056760
Ref: library/urllib request httpredirecthandler-objects12056760
Ref: 3c1912056760
Ref: library/urllib request urllib request HTTPRedirectHandler redirect_request12057266
Ref: 3c1a12057266
Ref: library/urllib request urllib request HTTPRedirectHandler http_error_30112058345
Ref: 3c1b12058345
Ref: library/urllib request urllib request HTTPRedirectHandler http_error_30212058616
Ref: 3c1c12058616
Ref: library/urllib request urllib request HTTPRedirectHandler http_error_30312058795
Ref: 3c1d12058795
Ref: library/urllib request urllib request HTTPRedirectHandler http_error_30712058978
Ref: 3c1e12058978
Ref: library/urllib request urllib request HTTPRedirectHandler http_error_30812059252
Ref: 3c1f12059252
Ref: HTTPRedirectHandler Objects-Footnote-112059591
Ref: HTTPRedirectHandler Objects-Footnote-212059650
Node: HTTPCookieProcessor Objects12059709
Ref: library/urllib request http-cookie-processor12059892
Ref: 3c2012059892
Ref: library/urllib request httpcookieprocessor-objects12059892
Ref: 3c2112059892
Ref: library/urllib request urllib request HTTPCookieProcessor cookiejar12060031
Ref: 3c2212060031
Node: ProxyHandler Objects12060159
Ref: library/urllib request proxy-handler12060338
Ref: 3c2412060338
Ref: library/urllib request proxyhandler-objects12060338
Ref: 3c2512060338
Node: HTTPPasswordMgr Objects12060816
Ref: library/urllib request http-password-mgr12061004
Ref: 3bf512061004
Ref: library/urllib request httppasswordmgr-objects12061004
Ref: 3c2612061004
Ref: library/urllib request urllib request HTTPPasswordMgr add_password12061190
Ref: 3c2712061190
Ref: library/urllib request urllib request HTTPPasswordMgr find_user_password12061537
Ref: 197b12061537
Node: HTTPPasswordMgrWithPriorAuth Objects12061911
Ref: library/urllib request http-password-mgr-with-prior-auth12062111
Ref: 3bf612062111
Ref: library/urllib request httppasswordmgrwithpriorauth-objects12062111
Ref: 3c2812062111
Ref: library/urllib request urllib request HTTPPasswordMgrWithPriorAuth add_password12062365
Ref: 3c2912062365
Ref: library/urllib request urllib request HTTPPasswordMgrWithPriorAuth find_user_password12062779
Ref: 3c2a12062779
Ref: library/urllib request urllib request HTTPPasswordMgrWithPriorAuth update_authenticated12062938
Ref: 3c2b12062938
Ref: library/urllib request urllib request HTTPPasswordMgrWithPriorAuth is_authenticated12063134
Ref: 197c12063134
Node: AbstractBasicAuthHandler Objects12063310
Ref: library/urllib request abstract-basic-auth-handler12063515
Ref: 3c2c12063515
Ref: library/urllib request abstractbasicauthhandler-objects12063515
Ref: 3c2d12063515
Ref: library/urllib request urllib request AbstractBasicAuthHandler http_error_auth_reqed12063600
Ref: 3c2e12063600
Node: HTTPBasicAuthHandler Objects12064421
Ref: library/urllib request http-basic-auth-handler12064619
Ref: 3c2f12064619
Ref: library/urllib request httpbasicauthhandler-objects12064619
Ref: 3c3012064619
Ref: library/urllib request urllib request HTTPBasicAuthHandler http_error_40112064698
Ref: 3c3112064698
Node: ProxyBasicAuthHandler Objects12064855
Ref: library/urllib request proxy-basic-auth-handler12065054
Ref: 3c3212065054
Ref: library/urllib request proxybasicauthhandler-objects12065054
Ref: 3c3312065054
Ref: library/urllib request urllib request ProxyBasicAuthHandler http_error_40712065135
Ref: 3c3412065135
Node: AbstractDigestAuthHandler Objects12065293
Ref: library/urllib request abstract-digest-auth-handler12065493
Ref: 3c3512065493
Ref: library/urllib request abstractdigestauthhandler-objects12065493
Ref: 3c3612065493
Ref: library/urllib request urllib request AbstractDigestAuthHandler http_error_auth_reqed12065582
Ref: 3c3712065582
Node: HTTPDigestAuthHandler Objects12065960
Ref: library/urllib request http-digest-auth-handler12066161
Ref: 3c3812066161
Ref: library/urllib request httpdigestauthhandler-objects12066161
Ref: 3c3912066161
Ref: library/urllib request urllib request HTTPDigestAuthHandler http_error_40112066242
Ref: 3c3a12066242
Node: ProxyDigestAuthHandler Objects12066400
Ref: library/urllib request proxy-digest-auth-handler12066587
Ref: 3c3b12066587
Ref: library/urllib request proxydigestauthhandler-objects12066587
Ref: 3c3c12066587
Ref: library/urllib request urllib request ProxyDigestAuthHandler http_error_40712066670
Ref: 3c3d12066670
Node: HTTPHandler Objects12066829
Ref: library/urllib request http-handler-objects12067007
Ref: 3c3e12067007
Ref: library/urllib request httphandler-objects12067007
Ref: 3c3f12067007
Ref: library/urllib request urllib request HTTPHandler http_open12067068
Ref: 3c4012067068
Node: HTTPSHandler Objects12067204
Ref: library/urllib request https-handler-objects12067371
Ref: 3c4112067371
Ref: library/urllib request httpshandler-objects12067371
Ref: 3c4212067371
Ref: library/urllib request urllib request HTTPSHandler https_open12067434
Ref: 3c4312067434
Node: FileHandler Objects12067573
Ref: library/urllib request file-handler-objects12067740
Ref: 3c4412067740
Ref: library/urllib request filehandler-objects12067740
Ref: 3c4512067740
Ref: library/urllib request urllib request FileHandler file_open12067801
Ref: 3c4612067801
Node: DataHandler Objects12068102
Ref: library/urllib request data-handler-objects12068267
Ref: 3c4712068267
Ref: library/urllib request datahandler-objects12068267
Ref: 3c4812068267
Ref: library/urllib request urllib request DataHandler data_open12068328
Ref: 3c4912068328
Ref: DataHandler Objects-Footnote-112068886
Node: FTPHandler Objects12068945
Ref: library/urllib request ftp-handler-objects12069114
Ref: 3c4a12069114
Ref: library/urllib request ftphandler-objects12069114
Ref: 3c4b12069114
Ref: library/urllib request urllib request FTPHandler ftp_open12069173
Ref: 3c4c12069173
Node: CacheFTPHandler Objects12069321
Ref: library/urllib request cacheftp-handler-objects12069493
Ref: 3c4d12069493
Ref: library/urllib request cacheftphandler-objects12069493
Ref: 3c4e12069493
Ref: library/urllib request urllib request CacheFTPHandler setTimeout12069675
Ref: 3c4f12069675
Ref: library/urllib request urllib request CacheFTPHandler setMaxConns12069768
Ref: 3c5012069768
Node: UnknownHandler Objects12069868
Ref: library/urllib request unknown-handler-objects12070048
Ref: 3c5112070048
Ref: library/urllib request unknownhandler-objects12070048
Ref: 3c5212070048
Ref: library/urllib request urllib request UnknownHandler unknown_open12070115
Ref: 3c5312070115
Node: HTTPErrorProcessor Objects12070206
Ref: library/urllib request http-error-processor-objects12070375
Ref: 3c5412070375
Ref: library/urllib request httperrorprocessor-objects12070375
Ref: 3c5512070375
Ref: library/urllib request urllib request HTTPErrorProcessor http_response12070450
Ref: 3c5612070450
Ref: library/urllib request urllib request HTTPErrorProcessor https_response12070921
Ref: 3c5712070921
Node: Examples<26>12071084
Ref: library/urllib request examples12071247
Ref: 3c5812071247
Ref: library/urllib request urllib-request-examples12071247
Ref: 3c5912071247
Ref: library/urllib request urllib-examples12077131
Ref: 3c5b12077131
Node: Legacy interface12078623
Ref: library/urllib request legacy-interface12078787
Ref: 3c5c12078787
Ref: library/urllib request urllib request urlretrieve12079018
Ref: 3c5d12079018
Ref: library/urllib request urllib request urlcleanup12081675
Ref: 1b6712081675
Ref: library/urllib request urllib request URLopener12081835
Ref: 30e12081835
Ref: library/urllib request urllib request URLopener open12083315
Ref: 3c6012083315
Ref: library/urllib request urllib request URLopener open_unknown12083818
Ref: 3c6112083818
Ref: library/urllib request urllib request URLopener retrieve12083930
Ref: 1b7e12083930
Ref: library/urllib request urllib request URLopener version12085479
Ref: 3c5f12085479
Ref: library/urllib request urllib request FancyURLopener12085800
Ref: 30f12085800
Ref: library/urllib request urllib request FancyURLopener prompt_user_passwd12087514
Ref: 3c6212087514
Ref: Legacy interface-Footnote-112088054
Node: urllib request Restrictions12088113
Ref: library/urllib request urllib-request-restrictions12088256
Ref: 3c6312088256
Node: urllib response — Response classes used by urllib12090823
Ref: library/urllib request module-urllib response12091056
Ref: 10c12091056
Ref: library/urllib request urllib-response-response-classes-used-by-urllib12091056
Ref: 3c6412091056
Ref: library/urllib request urllib response addinfourl12091513
Ref: 3be412091513
Ref: library/urllib request urllib response addinfourl url12091552
Ref: 3c6512091552
Ref: library/urllib request urllib response addinfourl headers12091684
Ref: 3c6612091684
Ref: library/urllib request urllib response addinfourl status12091823
Ref: 3c6712091823
Ref: library/urllib request urllib response addinfourl geturl12091927
Ref: 3c6812091927
Ref: library/urllib request urllib response addinfourl info12092046
Ref: 3c6912092046
Ref: library/urllib request urllib response addinfourl code12092167
Ref: 3c6a12092167
Ref: library/urllib request urllib response addinfourl getcode12092287
Ref: 3c6b12092287
Node: urllib parse — Parse URLs into components12092410
Ref: library/urllib parse doc12092648
Ref: 3c6c12092648
Ref: library/urllib parse module-urllib parse12092648
Ref: 10a12092648
Ref: library/urllib parse translation-repo12092648
Ref: 3c6d12092648
Ref: library/urllib parse urllib-parse-parse-urls-into-components12092648
Ref: 3c6e12092648
Ref: urllib parse — Parse URLs into components-Footnote-112094651
Ref: urllib parse — Parse URLs into components-Footnote-212094723
Ref: urllib parse — Parse URLs into components-Footnote-312094782
Node: URL Parsing12094841
Ref: library/urllib parse url-parsing12094961
Ref: 3c6f12094961
Ref: library/urllib parse urllib parse urlsplit12095134
Ref: d6712095134
Ref: library/urllib parse urllib parse parse_qs12103201
Ref: 27a12103201
Ref: library/urllib parse urllib parse parse_qsl12105382
Ref: 27912105382
Ref: library/urllib parse urllib parse urlunsplit12107413
Ref: 16de12107413
Ref: library/urllib parse urllib parse urlparse12107816
Ref: 30d12107816
Ref: library/urllib parse urllib parse urlunparse12108727
Ref: 16df12108727
Ref: library/urllib parse urllib parse urljoin12109170
Ref: eca12109170
Ref: library/urllib parse urllib parse urldefrag12110907
Ref: 128e12110907
Ref: library/urllib parse urllib parse unwrap12112252
Ref: 3c7612112252
Ref: URL Parsing-Footnote-112112600
Ref: URL Parsing-Footnote-212112659
Ref: URL Parsing-Footnote-312112721
Ref: URL Parsing-Footnote-412112780
Ref: URL Parsing-Footnote-512112839
Ref: URL Parsing-Footnote-612112898
Ref: URL Parsing-Footnote-712112957
Ref: URL Parsing-Footnote-812113016
Node: URL parsing security12113075
Ref: library/urllib parse id112113231
Ref: 3c7712113231
Ref: library/urllib parse url-parsing-security12113231
Ref: 3c7312113231
Ref: URL parsing security-Footnote-112114689
Ref: URL parsing security-Footnote-212114751
Node: Parsing ASCII Encoded Bytes12114810
Ref: library/urllib parse id212114979
Ref: 3c7812114979
Ref: library/urllib parse parsing-ascii-encoded-bytes12114979
Ref: 129012114979
Node: Structured Parse Results12117056
Ref: library/urllib parse structured-parse-results12117216
Ref: 3c7912117216
Ref: library/urllib parse urlparse-result-object12117216
Ref: 3c7212117216
Ref: library/urllib parse urllib parse urllib parse SplitResult geturl12117633
Ref: 3c7a12117633
Ref: library/urllib parse urllib parse DefragResult12118757
Ref: 3c7b12118757
Ref: library/urllib parse urllib parse ParseResult12119018
Ref: 3c7412119018
Ref: library/urllib parse urllib parse SplitResult12119289
Ref: 3c7012119289
Ref: library/urllib parse urllib parse DefragResultBytes12119694
Ref: 3c7c12119694
Ref: library/urllib parse urllib parse ParseResultBytes12119957
Ref: 3c7512119957
Ref: library/urllib parse urllib parse SplitResultBytes12120258
Ref: 3c7112120258
Node: URL Quoting12120551
Ref: library/urllib parse url-quoting12120675
Ref: 3c7d12120675
Ref: library/urllib parse urllib parse quote12121078
Ref: bc112121078
Ref: library/urllib parse urllib parse quote_plus12122453
Ref: 128f12122453
Ref: library/urllib parse urllib parse quote_from_bytes12122946
Ref: 18f512122946
Ref: library/urllib parse urllib parse unquote12123239
Ref: 189e12123239
Ref: library/urllib parse urllib parse unquote_plus12124020
Ref: 3c7e12124020
Ref: library/urllib parse urllib parse unquote_to_bytes12124360
Ref: 189f12124360
Ref: library/urllib parse urllib parse urlencode12124793
Ref: ec912124793
Ref: URL Quoting-Footnote-112128656
Ref: URL Quoting-Footnote-212128715
Ref: URL Quoting-Footnote-312128774
Ref: URL Quoting-Footnote-412128811
Ref: URL Quoting-Footnote-512128870
Ref: URL Quoting-Footnote-612128929
Ref: URL Quoting-Footnote-712128988
Ref: URL Quoting-Footnote-812129047
Ref: URL Quoting-Footnote-912129106
Node: urllib error — Exception classes raised by urllib request12129165
Ref: library/urllib error doc12129396
Ref: 3c7f12129396
Ref: library/urllib error module-urllib error12129396
Ref: 10912129396
Ref: library/urllib error translation-repo12129396
Ref: 3c8012129396
Ref: library/urllib error urllib-error-exception-classes-raised-by-urllib-request12129396
Ref: 3c8112129396
Ref: library/urllib error urllib error URLError12129883
Ref: 3be612129883
Ref: library/urllib error urllib error URLError reason12130061
Ref: 3c8212130061
Ref: library/urllib error urllib error HTTPError12130336
Ref: 101912130336
Ref: library/urllib error urllib error HTTPError url12130714
Ref: 3c8312130714
Ref: library/urllib error urllib error HTTPError code12130811
Ref: 3c8412130811
Ref: library/urllib error urllib error HTTPError reason12131071
Ref: 3c8612131071
Ref: library/urllib error urllib error HTTPError headers12131213
Ref: 101a12131213
Ref: library/urllib error urllib error HTTPError fp12131408
Ref: 3c8712131408
Ref: library/urllib error urllib error ContentTooShortError12131506
Ref: 3c5e12131506
Ref: library/urllib error urllib error ContentTooShortError content12131777
Ref: 3c8812131777
Ref: urllib error — Exception classes raised by urllib request-Footnote-112131901
Ref: urllib error — Exception classes raised by urllib request-Footnote-212131973
Node: urllib robotparser — Parser for robots txt12132032
Ref: library/urllib robotparser doc12132241
Ref: 3c8912132241
Ref: library/urllib robotparser module-urllib robotparser12132241
Ref: 10d12132241
Ref: library/urllib robotparser translation-repo12132241
Ref: 3c8a12132241
Ref: library/urllib robotparser urllib-robotparser-parser-for-robots-txt12132241
Ref: 3c8b12132241
Ref: library/urllib robotparser urllib robotparser RobotFileParser12132781
Ref: d2512132781
Ref: library/urllib robotparser urllib robotparser RobotFileParser set_url12132954
Ref: 3c8c12132954
Ref: library/urllib robotparser urllib robotparser RobotFileParser read12133048
Ref: 3c8d12133048
Ref: library/urllib robotparser urllib robotparser RobotFileParser parse12133144
Ref: 1c3412133144
Ref: library/urllib robotparser urllib robotparser RobotFileParser can_fetch12133214
Ref: 3c8e12133214
Ref: library/urllib robotparser urllib robotparser RobotFileParser mtime12133428
Ref: 3c8f12133428
Ref: library/urllib robotparser urllib robotparser RobotFileParser modified12133656
Ref: 3c9012133656
Ref: library/urllib robotparser urllib robotparser RobotFileParser crawl_delay12133785
Ref: 3c9112133785
Ref: library/urllib robotparser urllib robotparser RobotFileParser request_rate12134189
Ref: 3c9212134189
Ref: library/urllib robotparser urllib robotparser RobotFileParser site_maps12134642
Ref: 1bd112134642
Ref: urllib robotparser — Parser for robots txt-Footnote-112135551
Node: http — HTTP modules12135630
Ref: library/http doc12135816
Ref: 3c9312135816
Ref: library/http http-http-modules12135816
Ref: 3c9412135816
Ref: library/http module-http12135816
Ref: 6e12135816
Ref: library/http translation-repo12135816
Ref: 3c9512135816
Ref: library/http http HTTPStatus12136584
Ref: 90912136584
Ref: http — HTTP modules-Footnote-112137347
Node: HTTP status codes12137420
Ref: library/http http-status-codes12137524
Ref: 3c9612137524
Ref: library/http id112137524
Ref: 3c9712137524
Ref: HTTP status codes-Footnote-112151872
Ref: HTTP status codes-Footnote-212151956
Ref: HTTP status codes-Footnote-312152015
Ref: HTTP status codes-Footnote-412152074
Ref: HTTP status codes-Footnote-512152133
Ref: HTTP status codes-Footnote-612152192
Ref: HTTP status codes-Footnote-712152251
Ref: HTTP status codes-Footnote-812152310
Ref: HTTP status codes-Footnote-912152369
Ref: HTTP status codes-Footnote-1012152428
Ref: HTTP status codes-Footnote-1112152488
Ref: HTTP status codes-Footnote-1212152548
Ref: HTTP status codes-Footnote-1312152608
Ref: HTTP status codes-Footnote-1412152668
Ref: HTTP status codes-Footnote-1512152728
Ref: HTTP status codes-Footnote-1612152788
Ref: HTTP status codes-Footnote-1712152848
Ref: HTTP status codes-Footnote-1812152908
Ref: HTTP status codes-Footnote-1912152968
Ref: HTTP status codes-Footnote-2012153028
Ref: HTTP status codes-Footnote-2112153088
Ref: HTTP status codes-Footnote-2212153148
Ref: HTTP status codes-Footnote-2312153208
Ref: HTTP status codes-Footnote-2412153268
Ref: HTTP status codes-Footnote-2512153328
Ref: HTTP status codes-Footnote-2612153388
Ref: HTTP status codes-Footnote-2712153448
Ref: HTTP status codes-Footnote-2812153508
Ref: HTTP status codes-Footnote-2912153568
Ref: HTTP status codes-Footnote-3012153628
Ref: HTTP status codes-Footnote-3112153688
Ref: HTTP status codes-Footnote-3212153748
Ref: HTTP status codes-Footnote-3312153808
Ref: HTTP status codes-Footnote-3412153868
Ref: HTTP status codes-Footnote-3512153928
Ref: HTTP status codes-Footnote-3612153988
Ref: HTTP status codes-Footnote-3712154048
Ref: HTTP status codes-Footnote-3812154108
Ref: HTTP status codes-Footnote-3912154168
Ref: HTTP status codes-Footnote-4012154228
Ref: HTTP status codes-Footnote-4112154288
Ref: HTTP status codes-Footnote-4212154348
Ref: HTTP status codes-Footnote-4312154408
Ref: HTTP status codes-Footnote-4412154468
Ref: HTTP status codes-Footnote-4512154528
Ref: HTTP status codes-Footnote-4612154588
Ref: HTTP status codes-Footnote-4712154648
Ref: HTTP status codes-Footnote-4812154708
Ref: HTTP status codes-Footnote-4912154768
Ref: HTTP status codes-Footnote-5012154828
Ref: HTTP status codes-Footnote-5112154888
Ref: HTTP status codes-Footnote-5212154948
Ref: HTTP status codes-Footnote-5312155008
Ref: HTTP status codes-Footnote-5412155068
Ref: HTTP status codes-Footnote-5512155128
Ref: HTTP status codes-Footnote-5612155188
Ref: HTTP status codes-Footnote-5712155248
Ref: HTTP status codes-Footnote-5812155308
Ref: HTTP status codes-Footnote-5912155368
Ref: HTTP status codes-Footnote-6012155428
Ref: HTTP status codes-Footnote-6112155488
Ref: HTTP status codes-Footnote-6212155548
Ref: HTTP status codes-Footnote-6312155608
Node: HTTP status category12155668
Ref: library/http http-status-category12155793
Ref: 3c9812155793
Ref: library/http http HTTPMethod12157398
Ref: 3c9912157398
Ref: HTTP status category-Footnote-112158226
Ref: HTTP status category-Footnote-212158285
Ref: HTTP status category-Footnote-312158344
Ref: HTTP status category-Footnote-412158403
Ref: HTTP status category-Footnote-512158462
Node: HTTP methods12158521
Ref: library/http http-methods12158620
Ref: 3c9a12158620
Ref: library/http id212158620
Ref: 3c9b12158620
Ref: HTTP methods-Footnote-112160997
Ref: HTTP methods-Footnote-212161070
Ref: HTTP methods-Footnote-312161129
Ref: HTTP methods-Footnote-412161188
Ref: HTTP methods-Footnote-512161247
Ref: HTTP methods-Footnote-612161306
Ref: HTTP methods-Footnote-712161365
Ref: HTTP methods-Footnote-812161424
Ref: HTTP methods-Footnote-912161483
Ref: HTTP methods-Footnote-1012161542
Node: http client — HTTP protocol client12161602
Ref: library/http client doc12161774
Ref: 3c9c12161774
Ref: library/http client http-client-http-protocol-client12161774
Ref: 3c9d12161774
Ref: library/http client module-http client12161774
Ref: 6f12161774
Ref: library/http client translation-repo12161774
Ref: 3c9e12161774
Ref: library/http client http client HTTPConnection12162628
Ref: b5912162628
Ref: library/http client http client HTTPSConnection12164202
Ref: b5a12164202
Ref: library/http client http client HTTPResponse12165882
Ref: 111212165882
Ref: library/http client http client parse_headers12166264
Ref: 1bd912166264
Ref: library/http client http client HTTPException12167217
Ref: 3ca212167217
Ref: library/http client http client NotConnected12167368
Ref: 3ca312167368
Ref: library/http client http client InvalidURL12167456
Ref: 3ca412167456
Ref: library/http client http client UnknownProtocol12167609
Ref: 3ca512167609
Ref: library/http client http client UnknownTransferEncoding12167700
Ref: 3ca612167700
Ref: library/http client http client UnimplementedFileMode12167799
Ref: 3ca712167799
Ref: library/http client http client IncompleteRead12167896
Ref: 3ca812167896
Ref: library/http client http client ImproperConnectionState12167986
Ref: 3ca912167986
Ref: library/http client http client CannotSendRequest12168085
Ref: 3caa12168085
Ref: library/http client http client CannotSendHeader12168188
Ref: 3cab12168188
Ref: library/http client http client ResponseNotReady12168290
Ref: 3cac12168290
Ref: library/http client http client BadStatusLine12168392
Ref: 3cad12168392
Ref: library/http client http client LineTooLong12168567
Ref: 3cae12168567
Ref: library/http client http client RemoteDisconnected12168745
Ref: e3b12168745
Ref: library/http client http client HTTP_PORT12169227
Ref: 3caf12169227
Ref: library/http client http client HTTPS_PORT12169324
Ref: 3cb012169324
Ref: library/http client http client responses12169424
Ref: 3cb112169424
Ref: http client — HTTP protocol client-Footnote-112169885
Ref: http client — HTTP protocol client-Footnote-212169956
Ref: http client — HTTP protocol client-Footnote-312170007
Node: HTTPConnection Objects12170066
Ref: library/http client httpconnection-objects12170190
Ref: 3cb212170190
Ref: library/http client id112170190
Ref: 3cb312170190
Ref: library/http client http client HTTPConnection request12170323
Ref: ccf12170323
Ref: library/http client http client HTTPConnection getresponse12174128
Ref: e3a12174128
Ref: library/http client http client HTTPConnection set_debuglevel12174692
Ref: 3cb512174692
Ref: library/http client http client HTTPConnection set_tunnel12175096
Ref: 126e12175096
Ref: library/http client http client HTTPConnection get_proxy_response_headers12176762
Ref: 181212176762
Ref: library/http client http client HTTPConnection connect12177043
Ref: 3cb612177043
Ref: library/http client http client HTTPConnection close12177399
Ref: 3cb412177399
Ref: library/http client http client HTTPConnection blocksize12177478
Ref: 3cb712177478
Ref: library/http client http client HTTPConnection putrequest12177770
Ref: 3cb812177770
Ref: library/http client http client HTTPConnection putheader12178319
Ref: 3cb912178319
Ref: library/http client http client HTTPConnection endheaders12178654
Ref: cd012178654
Ref: library/http client http client HTTPConnection send12180025
Ref: 3cba12180025
Ref: HTTPConnection Objects-Footnote-112180394
Ref: HTTPConnection Objects-Footnote-212180467
Ref: HTTPConnection Objects-Footnote-312180540
Ref: HTTPConnection Objects-Footnote-412180613
Ref: HTTPConnection Objects-Footnote-512180681
Ref: HTTPConnection Objects-Footnote-612180739
Node: HTTPResponse Objects12180798
Ref: library/http client httpresponse-objects12180943
Ref: 3cbb12180943
Ref: library/http client id212180943
Ref: 3cbc12180943
Ref: library/http client http client HTTPResponse read12181358
Ref: 168812181358
Ref: library/http client http client HTTPResponse readinto12181471
Ref: 111312181471
Ref: library/http client http client HTTPResponse getheader12181660
Ref: 3cbd12181660
Ref: library/http client http client HTTPResponse getheaders12182047
Ref: 3cbe12182047
Ref: library/http client http client HTTPResponse fileno12182134
Ref: 3cbf12182134
Ref: library/http client http client HTTPResponse msg12182226
Ref: 3ca012182226
Ref: library/http client http client HTTPResponse version12182438
Ref: 3cc012182438
Ref: library/http client http client HTTPResponse url12182559
Ref: 3cc112182559
Ref: library/http client http client HTTPResponse headers12182689
Ref: 3cc212182689
Ref: library/http client http client HTTPResponse status12182828
Ref: 3cc312182828
Ref: library/http client http client HTTPResponse reason12182902
Ref: 3be512182902
Ref: library/http client http client HTTPResponse debuglevel12182978
Ref: 3cc412182978
Ref: library/http client http client HTTPResponse closed12183173
Ref: 3cc512183173
Ref: library/http client http client HTTPResponse geturl12183254
Ref: 3cc612183254
Ref: library/http client http client HTTPResponse info12183371
Ref: 3cc712183371
Ref: library/http client http client HTTPResponse getcode12183490
Ref: 3cc812183490
Node: Examples<27>12183611
Ref: library/http client examples12183753
Ref: 3cc912183753
Node: HTTPMessage Objects12186641
Ref: library/http client httpmessage-objects12186754
Ref: 3cca12186754
Ref: library/http client id312186754
Ref: 3ccb12186754
Ref: library/http client http client HTTPMessage12186815
Ref: 3c9f12186815
Node: ftplib — FTP protocol client12187036
Ref: library/ftplib doc12187218
Ref: 3ccc12187218
Ref: library/ftplib ftplib-ftp-protocol-client12187218
Ref: 3ccd12187218
Ref: library/ftplib module-ftplib12187218
Ref: 5e12187218
Ref: library/ftplib translation-repo12187218
Ref: 3cce12187218
Ref: ftplib — FTP protocol client-Footnote-112189055
Ref: ftplib — FTP protocol client-Footnote-212189121
Ref: ftplib — FTP protocol client-Footnote-312189179
Node: Reference<6>12189238
Ref: library/ftplib ftplib-reference12189317
Ref: 3ccf12189317
Ref: library/ftplib reference12189317
Ref: 3cd012189317
Node: FTP objects12189425
Ref: library/ftplib ftp-objects12189509
Ref: 3cd112189509
Ref: library/ftplib id112189509
Ref: 3cd212189509
Ref: library/ftplib ftplib FTP12189554
Ref: 90312189554
Ref: library/ftplib ftplib FTP set_debuglevel12192416
Ref: 3cd412192416
Ref: library/ftplib ftplib FTP connect12192973
Ref: 3cd312192973
Ref: library/ftplib ftplib FTP getwelcome12194358
Ref: 3cd512194358
Ref: library/ftplib ftplib FTP login12194614
Ref: 3cd612194614
Ref: library/ftplib ftplib FTP abort12195647
Ref: 3cd712195647
Ref: library/ftplib ftplib FTP sendcmd12195796
Ref: 3cd812195796
Ref: library/ftplib ftplib FTP voidcmd12196042
Ref: 3cd912196042
Ref: library/ftplib ftplib FTP retrbinary12196448
Ref: 3cdb12196448
Ref: library/ftplib ftplib FTP retrlines12197507
Ref: 3cdd12197507
Ref: library/ftplib ftplib FTP set_pasv12198244
Ref: 3cde12198244
Ref: library/ftplib ftplib FTP storbinary12198406
Ref: 135312198406
Ref: library/ftplib ftplib FTP storlines12199579
Ref: 3cdf12199579
Ref: library/ftplib ftplib FTP transfercmd12200077
Ref: 3cdc12200077
Ref: library/ftplib ftplib FTP ntransfercmd12201307
Ref: 3ce012201307
Ref: library/ftplib ftplib FTP mlsd12201677
Ref: 110612201677
Ref: library/ftplib ftplib FTP nlst12202432
Ref: 110712202432
Ref: library/ftplib ftplib FTP dir12202874
Ref: 110812202874
Ref: library/ftplib ftplib FTP rename12203571
Ref: 3ce112203571
Ref: library/ftplib ftplib FTP delete12203676
Ref: 3ce212203676
Ref: library/ftplib ftplib FTP cwd12203960
Ref: 3ce412203960
Ref: library/ftplib ftplib FTP mkd12204045
Ref: 3ce512204045
Ref: library/ftplib ftplib FTP pwd12204127
Ref: 3ce612204127
Ref: library/ftplib ftplib FTP rmd12204223
Ref: 3ce712204223
Ref: library/ftplib ftplib FTP size12204318
Ref: 3ce812204318
Ref: library/ftplib ftplib FTP quit12204669
Ref: 3ce912204669
Ref: library/ftplib ftplib FTP close12205103
Ref: 3cea12205103
Ref: FTP objects-Footnote-112205574
Ref: FTP objects-Footnote-212205632
Ref: FTP objects-Footnote-312205691
Ref: FTP objects-Footnote-412205749
Node: FTP_TLS objects12205808
Ref: library/ftplib ftp-tls-objects12205917
Ref: 3ceb12205917
Ref: library/ftplib ftplib FTP_TLS12205970
Ref: 90412205970
Ref: library/ftplib ftplib FTP_TLS ssl_version12209633
Ref: 3ced12209633
Ref: library/ftplib ftplib FTP_TLS auth12209758
Ref: 3cee12209758
Ref: library/ftplib ftplib FTP_TLS ccc12210148
Ref: 110512210148
Ref: library/ftplib ftplib FTP_TLS prot_p12210407
Ref: 3cec12210407
Ref: library/ftplib ftplib FTP_TLS prot_c12210477
Ref: 3cef12210477
Ref: FTP_TLS objects-Footnote-112210587
Ref: FTP_TLS objects-Footnote-212210646
Ref: FTP_TLS objects-Footnote-312210704
Node: Module variables12210763
Ref: library/ftplib module-variables12210852
Ref: 3cf012210852
Ref: library/ftplib ftplib error_reply12210907
Ref: 3cda12210907
Ref: library/ftplib ftplib error_temp12211024
Ref: 3cf112211024
Ref: library/ftplib ftplib error_perm12211187
Ref: 3ce312211187
Ref: library/ftplib ftplib error_proto12211350
Ref: 3cf212211350
Ref: library/ftplib ftplib all_errors12211581
Ref: 3cf312211581
Node: poplib — POP3 protocol client12212162
Ref: library/poplib doc12212341
Ref: 3cf412212341
Ref: library/poplib module-poplib12212341
Ref: ac12212341
Ref: library/poplib poplib-pop3-protocol-client12212341
Ref: 3cf512212341
Ref: library/poplib translation-repo12212341
Ref: 3cf612212341
Ref: library/poplib poplib POP312213599
Ref: 92d12213599
Ref: library/poplib poplib POP3_SSL12214516
Ref: 92e12214516
Ref: library/poplib poplib error_proto12216052
Ref: 11e012216052
Ref: poplib — POP3 protocol client-Footnote-112216705
Ref: poplib — POP3 protocol client-Footnote-212216771
Ref: poplib — POP3 protocol client-Footnote-312216830
Ref: poplib — POP3 protocol client-Footnote-412216889
Ref: poplib — POP3 protocol client-Footnote-512216948
Node: POP3 Objects12217010
Ref: library/poplib id112217111
Ref: 3cf712217111
Ref: library/poplib pop3-objects12217111
Ref: 3cf812217111
Ref: library/poplib poplib POP3 set_debuglevel12217342
Ref: 3cf912217342
Ref: library/poplib poplib POP3 getwelcome12217807
Ref: 3cfa12217807
Ref: library/poplib poplib POP3 capa12217898
Ref: fb512217898
Ref: library/poplib poplib POP3 user12218089
Ref: 3cfb12218089
Ref: library/poplib poplib POP3 pass_12218207
Ref: 3cfc12218207
Ref: library/poplib poplib POP3 apop12218402
Ref: 3cfd12218402
Ref: library/poplib poplib POP3 rpop12218520
Ref: 3cfe12218520
Ref: library/poplib poplib POP3 stat12218639
Ref: 3cff12218639
Ref: library/poplib poplib POP3 list12218771
Ref: 3d0012218771
Ref: library/poplib poplib POP3 retr12218963
Ref: 3d0112218963
Ref: library/poplib poplib POP3 dele12219126
Ref: 3d0212219126
Ref: library/poplib poplib POP3 rset12219404
Ref: 3d0312219404
Ref: library/poplib poplib POP3 noop12219479
Ref: 3d0412219479
Ref: library/poplib poplib POP3 quit12219555
Ref: 11df12219555
Ref: library/poplib poplib POP3 top12219645
Ref: 3d0512219645
Ref: library/poplib poplib POP3 uidl12220182
Ref: 3d0612220182
Ref: library/poplib poplib POP3 utf812220466
Ref: e7d12220466
Ref: library/poplib poplib POP3 stls12220676
Ref: fb612220676
Ref: POP3 Objects-Footnote-112221477
Ref: POP3 Objects-Footnote-212221536
Ref: POP3 Objects-Footnote-312221595
Node: POP3 Example12221654
Ref: library/poplib id212221755
Ref: 3d0712221755
Ref: library/poplib pop3-example12221755
Ref: 3d0812221755
Node: imaplib — IMAP4 protocol client12222267
Ref: library/imaplib doc12222448
Ref: 3d0912222448
Ref: library/imaplib imaplib-imap4-protocol-client12222448
Ref: 3d0a12222448
Ref: library/imaplib module-imaplib12222448
Ref: 7412222448
Ref: library/imaplib translation-repo12222448
Ref: 3d0b12222448
Ref: library/imaplib imaplib IMAP412223270
Ref: 90c12223270
Ref: library/imaplib imaplib IMAP4 error12224474
Ref: 161b12224474
Ref: library/imaplib imaplib IMAP4 abort12224617
Ref: 3d0c12224617
Ref: library/imaplib imaplib IMAP4 readonly12224879
Ref: 3d0d12224879
Ref: library/imaplib imaplib IMAP4_SSL12225236
Ref: 90d12225236
Ref: library/imaplib imaplib IMAP4_stream12226648
Ref: 90f12226648
Ref: library/imaplib imaplib Internaldate2tuple12226918
Ref: 3d0e12226918
Ref: library/imaplib imaplib Int2AP12227168
Ref: 3d0f12227168
Ref: library/imaplib imaplib ParseFlags12227316
Ref: 3d1012227316
Ref: library/imaplib imaplib Time2Internaldate12227437
Ref: 3d1112227437
Ref: imaplib — IMAP4 protocol client-Footnote-112228780
Ref: imaplib — IMAP4 protocol client-Footnote-212228847
Ref: imaplib — IMAP4 protocol client-Footnote-312228906
Node: IMAP4 Objects12228965
Ref: library/imaplib id112229070
Ref: 3d1212229070
Ref: library/imaplib imap4-objects12229070
Ref: 3d1312229070
Ref: library/imaplib imaplib IMAP4 append12230572
Ref: 3d1412230572
Ref: library/imaplib imaplib IMAP4 authenticate12230676
Ref: 3d1512230676
Ref: library/imaplib imaplib IMAP4 check12231512
Ref: 3d1612231512
Ref: library/imaplib imaplib IMAP4 close12231576
Ref: 91112231576
Ref: library/imaplib imaplib IMAP4 copy12231761
Ref: 3d1712231761
Ref: library/imaplib imaplib IMAP4 create12231873
Ref: 3d1812231873
Ref: library/imaplib imaplib IMAP4 delete12231951
Ref: 3d1912231951
Ref: library/imaplib imaplib IMAP4 deleteacl12232029
Ref: 3d1a12232029
Ref: library/imaplib imaplib IMAP4 enable12232139
Ref: e3f12232139
Ref: library/imaplib imaplib IMAP4 expunge12232452
Ref: 3d1b12232452
Ref: library/imaplib imaplib IMAP4 fetch12232700
Ref: 3d1c12232700
Ref: library/imaplib imaplib IMAP4 getacl12232980
Ref: 3d1d12232980
Ref: library/imaplib imaplib IMAP4 getannotation12233134
Ref: 3d1e12233134
Ref: library/imaplib imaplib IMAP4 getquota12233335
Ref: 3d1f12233335
Ref: library/imaplib imaplib IMAP4 getquotaroot12233509
Ref: 3d2012233509
Ref: library/imaplib imaplib IMAP4 list12233697
Ref: 3d2112233697
Ref: library/imaplib imaplib IMAP4 login12233966
Ref: 3d2212233966
Ref: library/imaplib imaplib IMAP4 login_cram_md512234099
Ref: 161a12234099
Ref: library/imaplib imaplib IMAP4 logout12234468
Ref: aa212234468
Ref: library/imaplib imaplib IMAP4 lsub12234665
Ref: 3d2312234665
Ref: library/imaplib imaplib IMAP4 myrights12234955
Ref: 3d2412234955
Ref: library/imaplib imaplib IMAP4 namespace12235074
Ref: 3d2512235074
Ref: library/imaplib imaplib IMAP4 noop12235163
Ref: 3d2612235163
Ref: library/imaplib imaplib IMAP4 open12235223
Ref: 90e12235223
Ref: library/imaplib imaplib IMAP4 partial12236169
Ref: 3d2b12236169
Ref: library/imaplib imaplib IMAP4 proxyauth12236346
Ref: 3d2c12236346
Ref: library/imaplib imaplib IMAP4 read12236498
Ref: 3d2712236498
Ref: library/imaplib imaplib IMAP4 readline12236614
Ref: 3d2812236614
Ref: library/imaplib imaplib IMAP4 recent12236726
Ref: 3d2d12236726
Ref: library/imaplib imaplib IMAP4 rename12236881
Ref: 3d2e12236881
Ref: library/imaplib imaplib IMAP4 response12236989
Ref: 3d2f12236989
Ref: library/imaplib imaplib IMAP4 search12237147
Ref: 3d3012237147
Ref: library/imaplib imaplib IMAP4 select12237822
Ref: 3d3112237822
Ref: library/imaplib imaplib IMAP4 send12238117
Ref: 3d2912238117
Ref: library/imaplib imaplib IMAP4 setacl12238331
Ref: 3d3212238331
Ref: library/imaplib imaplib IMAP4 setannotation12238494
Ref: 3d3312238494
Ref: library/imaplib imaplib IMAP4 setquota12238683
Ref: 3d3412238683
Ref: library/imaplib imaplib IMAP4 shutdown12238857
Ref: 3d2a12238857
Ref: library/imaplib imaplib IMAP4 socket12239038
Ref: 3d3512239038
Ref: library/imaplib imaplib IMAP4 sort12239124
Ref: 3d3612239124
Ref: library/imaplib imaplib IMAP4 starttls12240068
Ref: 126b12240068
Ref: library/imaplib imaplib IMAP4 status12240597
Ref: 3d3712240597
Ref: library/imaplib imaplib IMAP4 store12240693
Ref: 3d3812240693
Ref: library/imaplib imaplib IMAP4 subscribe12241894
Ref: 3d3912241894
Ref: library/imaplib imaplib IMAP4 thread12241965
Ref: 3d3a12241965
Ref: library/imaplib imaplib IMAP4 uid12243094
Ref: 3d3b12243094
Ref: library/imaplib imaplib IMAP4 unsubscribe12243412
Ref: 3d3c12243412
Ref: library/imaplib imaplib IMAP4 unselect12243489
Ref: 91012243489
Ref: library/imaplib imaplib IMAP4 xatom12243888
Ref: 3d3d12243888
Ref: library/imaplib imaplib IMAP4 PROTOCOL_VERSION12244092
Ref: 3d3e12244092
Ref: library/imaplib imaplib IMAP4 debug12244227
Ref: 3d3f12244227
Ref: library/imaplib imaplib IMAP4 utf8_enabled12244430
Ref: e4012244430
Ref: IMAP4 Objects-Footnote-112244710
Ref: IMAP4 Objects-Footnote-212244769
Ref: IMAP4 Objects-Footnote-312244828
Ref: IMAP4 Objects-Footnote-412244887
Ref: IMAP4 Objects-Footnote-512244946
Ref: IMAP4 Objects-Footnote-612245005
Node: IMAP4 Example12245064
Ref: library/imaplib id212245169
Ref: 3d4012245169
Ref: library/imaplib imap4-example12245169
Ref: 3d4112245169
Node: smtplib — SMTP protocol client12245675
Ref: library/smtplib doc12245868
Ref: 3d4212245868
Ref: library/smtplib module-smtplib12245868
Ref: ca12245868
Ref: library/smtplib smtplib-smtp-protocol-client12245868
Ref: 3d4312245868
Ref: library/smtplib translation-repo12245868
Ref: 3d4412245868
Ref: library/smtplib smtplib SMTP12246515
Ref: 93712246515
Ref: library/smtplib smtplib SMTP_SSL12249100
Ref: 93812249100
Ref: library/smtplib smtplib LMTP12250566
Ref: 93912250566
Ref: library/smtplib smtplib SMTPException12251494
Ref: fda12251494
Ref: library/smtplib smtplib SMTPServerDisconnected12251750
Ref: 3d4712251750
Ref: library/smtplib smtplib SMTPResponseException12251978
Ref: 3d4812251978
Ref: library/smtplib smtplib SMTPResponseException smtp_code12252196
Ref: 3d4912252196
Ref: library/smtplib smtplib SMTPResponseException smtp_error12252254
Ref: 3d4a12252254
Ref: library/smtplib smtplib SMTPSenderRefused12252316
Ref: 3d4b12252316
Ref: library/smtplib smtplib SMTPRecipientsRefused12252557
Ref: 3d4c12252557
Ref: library/smtplib smtplib SMTPRecipientsRefused recipients12252642
Ref: 3d4d12252642
Ref: library/smtplib smtplib SMTPDataError12252828
Ref: 3d4e12252828
Ref: library/smtplib smtplib SMTPConnectError12252924
Ref: 3d4512252924
Ref: library/smtplib smtplib SMTPHeloError12253045
Ref: 3d4f12253045
Ref: library/smtplib smtplib SMTPNotSupportedError12253132
Ref: 1b5912253132
Ref: library/smtplib smtplib SMTPAuthenticationError12253276
Ref: 3d5012253276
Ref: smtplib — SMTP protocol client-Footnote-112253999
Ref: smtplib — SMTP protocol client-Footnote-212254066
Ref: smtplib — SMTP protocol client-Footnote-312254124
Ref: smtplib — SMTP protocol client-Footnote-412254183
Ref: smtplib — SMTP protocol client-Footnote-512254242
Ref: smtplib — SMTP protocol client-Footnote-612254300
Node: SMTP Objects12254359
Ref: library/smtplib id112254461
Ref: 3d5112254461
Ref: library/smtplib smtp-objects12254461
Ref: 3d5212254461
Ref: library/smtplib smtplib SMTP set_debuglevel12254565
Ref: e8c12254565
Ref: library/smtplib smtplib SMTP docmd12254916
Ref: 3d5312254916
Ref: library/smtplib smtplib SMTP connect12255566
Ref: 1b5a12255566
Ref: library/smtplib smtplib SMTP helo12256252
Ref: 3d5412256252
Ref: library/smtplib smtplib SMTP ehlo12256719
Ref: 3d5612256719
Ref: library/smtplib smtplib SMTP ehlo_or_helo_if_needed12257645
Ref: 3d5b12257645
Ref: library/smtplib smtplib SMTP has_extn12257987
Ref: 3d5712257987
Ref: library/smtplib smtplib SMTP verify12258182
Ref: 3d5c12258182
Ref: library/smtplib smtplib SMTP login12258601
Ref: 3d5d12258601
Ref: library/smtplib smtplib SMTP auth12260170
Ref: e8b12260170
Ref: library/smtplib smtplib SMTP starttls12262417
Ref: 117c12262417
Ref: library/smtplib smtplib SMTP sendmail12263930
Ref: e8d12263930
Ref: library/smtplib smtplib SMTP send_message12267372
Ref: e8e12267372
Ref: library/smtplib smtplib SMTP quit12269446
Ref: 3d4612269446
Ref: library/smtplib smtplib SMTP helo_resp12269935
Ref: 3d5512269935
Ref: library/smtplib smtplib SMTP ehlo_resp12270036
Ref: 3d5812270036
Ref: library/smtplib smtplib SMTP does_esmtp12270137
Ref: 3d5912270137
Ref: library/smtplib smtplib SMTP esmtp_features12270266
Ref: 3d5a12270266
Ref: SMTP Objects-Footnote-112270451
Ref: SMTP Objects-Footnote-212270509
Ref: SMTP Objects-Footnote-312270568
Ref: SMTP Objects-Footnote-412270627
Ref: SMTP Objects-Footnote-512270685
Ref: SMTP Objects-Footnote-612270743
Node: SMTP Example12270802
Ref: library/smtplib id212270904
Ref: 3d5e12270904
Ref: library/smtplib smtp-example12270904
Ref: 3d5f12270904
Ref: SMTP Example-Footnote-112272332
Node: uuid — UUID objects according to RFC 412212272390
Ref: library/uuid doc12272598
Ref: 3d6012272598
Ref: library/uuid module-uuid12272598
Ref: 11012272598
Ref: library/uuid translation-repo12272598
Ref: 3d6112272598
Ref: library/uuid uuid-uuid-objects-according-to-rfc-412212272598
Ref: 3d6212272598
Ref: library/uuid uuid SafeUUID12273700
Ref: 3d6312273700
Ref: library/uuid uuid SafeUUID safe12273754
Ref: 3d6412273754
Ref: library/uuid uuid SafeUUID unsafe12273871
Ref: 3d6512273871
Ref: library/uuid uuid SafeUUID unknown12273968
Ref: 3d6612273968
Ref: library/uuid uuid UUID12274109
Ref: a6f12274109
Ref: library/uuid uuid UUID bytes12276070
Ref: 3d6812276070
Ref: library/uuid uuid UUID bytes_le12276199
Ref: 3d6912276199
Ref: library/uuid uuid UUID fields12276351
Ref: 3d6a12276351
Ref: library/uuid uuid UUID time_low12276722
Ref: 3d6b12276722
Ref: library/uuid uuid UUID time_mid12276920
Ref: 3d6c12276920
Ref: library/uuid uuid UUID time_hi_version12277124
Ref: 3d6d12277124
Ref: library/uuid uuid UUID clock_seq_hi_variant12277326
Ref: 3d6e12277326
Ref: library/uuid uuid UUID clock_seq_low12277515
Ref: 3d6f12277515
Ref: library/uuid uuid UUID node12277702
Ref: 3d7012277702
Ref: library/uuid uuid UUID time12277899
Ref: 3d7112277899
Ref: library/uuid uuid UUID clock_seq12278093
Ref: 3d7212278093
Ref: library/uuid uuid UUID hex12278204
Ref: 3d7312278204
Ref: library/uuid uuid UUID int12278292
Ref: 3d6712278292
Ref: library/uuid uuid UUID urn12278354
Ref: 3d7412278354
Ref: library/uuid uuid UUID variant12278432
Ref: 3d7512278432
Ref: library/uuid uuid UUID version12278696
Ref: 3d7a12278696
Ref: library/uuid uuid UUID is_safe12278834
Ref: bc412278834
Ref: library/uuid uuid getnode12279085
Ref: bc512279085
Ref: library/uuid uuid uuid112280055
Ref: bc612280055
Ref: library/uuid uuid uuid312280407
Ref: 166412280407
Ref: library/uuid uuid uuid412280644
Ref: 166512280644
Ref: library/uuid uuid uuid512280703
Ref: 166612280703
Ref: library/uuid uuid NAMESPACE_DNS12281067
Ref: 3d7b12281067
Ref: library/uuid uuid NAMESPACE_URL12281194
Ref: 3d7c12281194
Ref: library/uuid uuid NAMESPACE_OID12281292
Ref: 3d7d12281292
Ref: library/uuid uuid NAMESPACE_X50012281395
Ref: 3d7e12281395
Ref: library/uuid uuid RESERVED_NCS12281654
Ref: 3d7612281654
Ref: library/uuid uuid RFC_412212281721
Ref: 3d7712281721
Ref: library/uuid uuid RESERVED_MICROSOFT12281800
Ref: 3d7812281800
Ref: library/uuid uuid RESERVED_FUTURE12281879
Ref: 3d7912281879
Ref: uuid — UUID objects according to RFC 4122-Footnote-112282327
Ref: uuid — UUID objects according to RFC 4122-Footnote-212282391
Ref: uuid — UUID objects according to RFC 4122-Footnote-312282450
Ref: uuid — UUID objects according to RFC 4122-Footnote-412282509
Ref: uuid — UUID objects according to RFC 4122-Footnote-512282568
Ref: uuid — UUID objects according to RFC 4122-Footnote-612282627
Ref: uuid — UUID objects according to RFC 4122-Footnote-712282686
Node: Command-Line Usage<2>12282745
Ref: library/uuid command-line-usage12282866
Ref: 3d7f12282866
Ref: library/uuid uuid-cli12282866
Ref: 44712282866
Ref: library/uuid cmdoption-uuid-h12283142
Ref: 3d8012283142
Ref: library/uuid cmdoption-uuid-help12283142
Ref: 3d8112283142
Ref: library/uuid cmdoption-uuid-u12283204
Ref: 3d8212283204
Ref: library/uuid cmdoption-uuid-uuid12283226
Ref: 3d8312283226
Ref: library/uuid cmdoption-uuid-n12283361
Ref: 3d8412283361
Ref: library/uuid cmdoption-uuid-namespace12283388
Ref: 3d8512283388
Ref: library/uuid cmdoption-uuid-N12283702
Ref: 3d8612283702
Ref: library/uuid cmdoption-uuid-name12283724
Ref: 3d8712283724
Node: Example<11>12283882
Ref: library/uuid example12284032
Ref: 3d8812284032
Ref: library/uuid uuid-example12284032
Ref: 3d8912284032
Node: Command-Line Example12285285
Ref: library/uuid command-line-example12285405
Ref: 3d8a12285405
Ref: library/uuid uuid-cli-example12285405
Ref: 3d8b12285405
Node: socketserver — A framework for network servers12285792
Ref: library/socketserver doc12285996
Ref: 3d8c12285996
Ref: library/socketserver module-socketserver12285996
Ref: cd12285996
Ref: library/socketserver socketserver-a-framework-for-network-servers12285996
Ref: 3d8d12285996
Ref: library/socketserver translation-repo12285996
Ref: 3d8e12285996
Ref: library/socketserver socketserver TCPServer12286513
Ref: 136912286513
Ref: library/socketserver socketserver UDPServer12286985
Ref: 3d9112286985
Ref: library/socketserver socketserver UnixStreamServer12287288
Ref: 3d9212287288
Ref: library/socketserver socketserver UnixDatagramServer12287401
Ref: 3d9312287401
Ref: socketserver — A framework for network servers-Footnote-112289724
Node: Server Creation Notes12289796
Ref: library/socketserver server-creation-notes12289925
Ref: 3d9612289925
Ref: library/socketserver socketserver ForkingMixIn12290698
Ref: b9612290698
Ref: library/socketserver socketserver ThreadingMixIn12290735
Ref: b5e12290735
Ref: library/socketserver socketserver ThreadingMixIn block_on_close12291383
Ref: b9512291383
Ref: library/socketserver socketserver ThreadingMixIn daemon_threads12291772
Ref: 3d9812291772
Ref: library/socketserver socketserver ForkingTCPServer12292290
Ref: 3d9912292290
Ref: library/socketserver socketserver ForkingUDPServer12292331
Ref: 3d9a12292331
Ref: library/socketserver socketserver ThreadingTCPServer12292372
Ref: 3d9b12292372
Ref: library/socketserver socketserver ThreadingUDPServer12292415
Ref: 3d9712292415
Ref: library/socketserver socketserver ForkingUnixStreamServer12292458
Ref: 3d9c12292458
Ref: library/socketserver socketserver ForkingUnixDatagramServer12292506
Ref: 3d9d12292506
Ref: library/socketserver socketserver ThreadingUnixStreamServer12292556
Ref: 3d9e12292556
Ref: library/socketserver socketserver ThreadingUnixDatagramServer12292606
Ref: 3d9f12292606
Node: Server Objects12294964
Ref: library/socketserver server-objects12295125
Ref: 3da112295125
Ref: library/socketserver socketserver BaseServer12295176
Ref: 118112295176
Ref: library/socketserver socketserver BaseServer fileno12295575
Ref: 3da412295575
Ref: library/socketserver socketserver BaseServer handle_request12295848
Ref: 136c12295848
Ref: library/socketserver socketserver BaseServer serve_forever12296443
Ref: 118312296443
Ref: library/socketserver socketserver BaseServer service_actions12297089
Ref: 118212297089
Ref: library/socketserver socketserver BaseServer shutdown12297392
Ref: 1bc512297392
Ref: library/socketserver socketserver BaseServer server_close12297660
Ref: b9412297660
Ref: library/socketserver socketserver BaseServer address_family12297746
Ref: 3da812297746
Ref: library/socketserver socketserver BaseServer RequestHandlerClass12298160
Ref: 3da312298160
Ref: library/socketserver socketserver BaseServer server_address12298318
Ref: 3da212298318
Ref: library/socketserver socketserver BaseServer socket12298741
Ref: 3da912298741
Ref: library/socketserver socketserver BaseServer allow_reuse_address12298927
Ref: 3daa12298927
Ref: library/socketserver socketserver BaseServer request_queue_size12299141
Ref: 3dab12299141
Ref: library/socketserver socketserver BaseServer socket_type12299632
Ref: 3dac12299632
Ref: library/socketserver socketserver BaseServer timeout12299825
Ref: 136a12299825
Ref: library/socketserver socketserver BaseServer finish_request12300331
Ref: 3dad12300331
Ref: library/socketserver socketserver BaseServer get_request12300548
Ref: 3da512300548
Ref: library/socketserver socketserver BaseServer handle_error12300778
Ref: d6a12300778
Ref: library/socketserver socketserver BaseServer handle_timeout12301230
Ref: 136b12301230
Ref: library/socketserver socketserver BaseServer process_request12301669
Ref: 3da712301669
Ref: library/socketserver socketserver BaseServer server_activate12302040
Ref: 3d9012302040
Ref: library/socketserver socketserver BaseServer server_bind12302287
Ref: 3d8f12302287
Ref: library/socketserver socketserver BaseServer verify_request12302441
Ref: 3da612302441
Node: Request Handler Objects12303020
Ref: library/socketserver request-handler-objects12303172
Ref: 3dae12303172
Ref: library/socketserver socketserver BaseRequestHandler12303241
Ref: 3d9412303241
Ref: library/socketserver socketserver BaseRequestHandler setup12303595
Ref: 3daf12303595
Ref: library/socketserver socketserver BaseRequestHandler handle12303790
Ref: 3d9512303790
Ref: library/socketserver socketserver BaseRequestHandler finish12304491
Ref: 3db312304491
Ref: library/socketserver socketserver BaseRequestHandler request12304770
Ref: 3db012304770
Ref: library/socketserver socketserver BaseRequestHandler client_address12304906
Ref: 3db112304906
Ref: library/socketserver socketserver BaseRequestHandler server12305028
Ref: 3db212305028
Ref: library/socketserver socketserver StreamRequestHandler12305129
Ref: d0112305129
Ref: library/socketserver socketserver DatagramRequestHandler12305174
Ref: 3da012305174
Ref: library/socketserver socketserver DatagramRequestHandler rfile12305421
Ref: 3db412305421
Ref: library/socketserver socketserver DatagramRequestHandler wfile12305586
Ref: d0012305586
Node: Examples<28>12305862
Ref: library/socketserver examples12305991
Ref: 3db512305991
Node: socketserver TCPServer Example12306196
Ref: library/socketserver socketserver-tcpserver-example12306314
Ref: 3db612306314
Node: socketserver UDPServer Example12310151
Ref: library/socketserver socketserver-udpserver-example12310297
Ref: 3db712310297
Node: Asynchronous Mixins12311886
Ref: library/socketserver asynchronous-mixins12311993
Ref: 3db812311993
Node: http server — HTTP servers12314339
Ref: library/http server doc12314538
Ref: 3db912314538
Ref: library/http server http-server-http-servers12314538
Ref: 3dba12314538
Ref: library/http server module-http server12314538
Ref: 7212314538
Ref: library/http server translation-repo12314538
Ref: 3dbb12314538
Ref: library/http server http server HTTPServer12315505
Ref: 3bb312315505
Ref: library/http server http server ThreadingHTTPServer12315860
Ref: b5d12315860
Ref: library/http server http server BaseHTTPRequestHandler12316410
Ref: 110f12316410
Ref: library/http server http server BaseHTTPRequestHandler client_address12317377
Ref: 3dbd12317377
Ref: library/http server http server BaseHTTPRequestHandler server12317519
Ref: 3dbe12317519
Ref: library/http server http server BaseHTTPRequestHandler close_connection12317588
Ref: 3dbf12317588
Ref: library/http server http server BaseHTTPRequestHandler requestline12317823
Ref: 3dc112317823
Ref: library/http server http server BaseHTTPRequestHandler command12318138
Ref: 3dc212318138
Ref: library/http server http server BaseHTTPRequestHandler path12318242
Ref: 3dc312318242
Ref: library/http server http server BaseHTTPRequestHandler request_version12318516
Ref: 3dc412318516
Ref: library/http server http server BaseHTTPRequestHandler headers12318652
Ref: 3ca112318652
Ref: library/http server http server BaseHTTPRequestHandler rfile12319079
Ref: 3dc612319079
Ref: library/http server http server BaseHTTPRequestHandler wfile12319231
Ref: 3dc712319231
Ref: library/http server http server BaseHTTPRequestHandler server_version12319673
Ref: 3dc812319673
Ref: library/http server http server BaseHTTPRequestHandler sys_version12319960
Ref: 3dc912319960
Ref: library/http server http server BaseHTTPRequestHandler error_message_format12320215
Ref: f8912320215
Ref: library/http server http server BaseHTTPRequestHandler error_content_type12320571
Ref: 3dcb12320571
Ref: library/http server http server BaseHTTPRequestHandler protocol_version12320751
Ref: 3dcc12320751
Ref: library/http server http server BaseHTTPRequestHandler MessageClass12321347
Ref: 3dc512321347
Ref: library/http server http server BaseHTTPRequestHandler responses12321585
Ref: 3c8512321585
Ref: library/http server http server BaseHTTPRequestHandler handle12322139
Ref: 3dcf12322139
Ref: library/http server http server BaseHTTPRequestHandler handle_one_request12322439
Ref: 3dc012322439
Ref: library/http server http server BaseHTTPRequestHandler handle_expect_10012322637
Ref: 3dd012322637
Ref: library/http server http server BaseHTTPRequestHandler send_error12323148
Ref: f8812323148
Ref: library/http server http server BaseHTTPRequestHandler send_response12324275
Ref: 3dd112324275
Ref: library/http server http server BaseHTTPRequestHandler send_header12325086
Ref: 3dcd12325086
Ref: library/http server http server BaseHTTPRequestHandler send_response_only12325734
Ref: 3dce12325734
Ref: library/http server http server BaseHTTPRequestHandler end_headers12326242
Ref: 111012326242
Ref: library/http server http server BaseHTTPRequestHandler flush_headers12326542
Ref: 111112326542
Ref: library/http server http server BaseHTTPRequestHandler log_request12326716
Ref: 3dd312326716
Ref: library/http server http server BaseHTTPRequestHandler log_error12327013
Ref: 3dd412327013
Ref: library/http server http server BaseHTTPRequestHandler log_message12327258
Ref: 3dd512327258
Ref: library/http server http server BaseHTTPRequestHandler version_string12327730
Ref: 3dca12327730
Ref: library/http server http server BaseHTTPRequestHandler date_time_string12327944
Ref: 3dd212327944
Ref: library/http server http server BaseHTTPRequestHandler log_date_time_string12328332
Ref: 3dd612328332
Ref: library/http server http server BaseHTTPRequestHandler address_string12328443
Ref: 3dd712328443
Ref: library/http server http server SimpleHTTPRequestHandler12328686
Ref: b5c12328686
Ref: library/http server http server SimpleHTTPRequestHandler server_version12329467
Ref: 3dda12329467
Ref: library/http server http server SimpleHTTPRequestHandler extensions_map12329628
Ref: 3ddb12329628
Ref: library/http server http server SimpleHTTPRequestHandler do_HEAD12330119
Ref: 3dd912330119
Ref: library/http server http server SimpleHTTPRequestHandler do_GET12330407
Ref: 3dd812330407
Ref: library/http server http server CGIHTTPRequestHandler12332841
Ref: 2a112332841
Ref: library/http server http server CGIHTTPRequestHandler cgi_directories12334013
Ref: 3ddc12334013
Ref: library/http server http server CGIHTTPRequestHandler do_POST12334247
Ref: 3ddd12334247
Ref: http server — HTTP servers-Footnote-112335181
Ref: http server — HTTP servers-Footnote-212335252
Ref: http server — HTTP servers-Footnote-312335311
Ref: http server — HTTP servers-Footnote-412335370
Node: Command-line interface<5>12335441
Ref: library/http server command-line-interface12335566
Ref: 3dde12335566
Ref: library/http server http-server-cli12335566
Ref: f8a12335566
Ref: library/http server cmdoption-http server-arg-port12335904
Ref: 3ddf12335904
Ref: library/http server cmdoption-http server-b12336097
Ref: 3de012336097
Ref: library/http server cmdoption-http server-bind12336097
Ref: 3de112336097
Ref: library/http server cmdoption-http server-d12336537
Ref: 3de212336537
Ref: library/http server cmdoption-http server-directory12336537
Ref: 3de312336537
Ref: library/http server cmdoption-http server-p12336840
Ref: 3de412336840
Ref: library/http server cmdoption-http server-protocol12336840
Ref: 3de512336840
Ref: library/http server cmdoption-http server-cgi12337161
Ref: 3de612337161
Node: Security considerations<3>12337772
Ref: library/http server http-server-security12337897
Ref: 3dbc12337897
Ref: library/http server security-considerations12337897
Ref: 3de712337897
Node: http cookies — HTTP state management12338836
Ref: library/http cookies doc12339038
Ref: 3de812339038
Ref: library/http cookies http-cookies-http-state-management12339038
Ref: 3de912339038
Ref: library/http cookies module-http cookies12339038
Ref: 7112339038
Ref: library/http cookies translation-repo12339038
Ref: 3dea12339038
Ref: library/http cookies http cookies CookieError12340422
Ref: 3deb12340422
Ref: library/http cookies http cookies BaseCookie12340589
Ref: 3dec12340589
Ref: library/http cookies http cookies SimpleCookie12340972
Ref: 1bd312340972
Ref: http cookies — HTTP state management-Footnote-112341821
Ref: http cookies — HTTP state management-Footnote-212341893
Ref: http cookies — HTTP state management-Footnote-312341952
Ref: http cookies — HTTP state management-Footnote-412342011
Ref: http cookies — HTTP state management-Footnote-512342070
Node: Cookie Objects12342129
Ref: library/http cookies cookie-objects12342241
Ref: 3df012342241
Ref: library/http cookies id112342241
Ref: 3df112342241
Ref: library/http cookies http cookies BaseCookie value_decode12342292
Ref: 3dee12342292
Ref: library/http cookies http cookies BaseCookie value_encode12342564
Ref: 3def12342564
Ref: library/http cookies http cookies BaseCookie output12343004
Ref: 3df212343004
Ref: library/http cookies http cookies BaseCookie js_output12343372
Ref: 15a612343372
Ref: library/http cookies http cookies BaseCookie load12343651
Ref: 3ded12343651
Node: Morsel Objects12343933
Ref: library/http cookies id212344065
Ref: 3df412344065
Ref: library/http cookies morsel-objects12344065
Ref: 3df512344065
Ref: library/http cookies http cookies Morsel12344116
Ref: c2412344116
Ref: library/http cookies http cookies Morsel expires12344347
Ref: 3df612344347
Ref: library/http cookies http cookies Morsel path12344380
Ref: 3df712344380
Ref: library/http cookies http cookies Morsel comment12344410
Ref: 3df812344410
Ref: library/http cookies http cookies Morsel domain12344443
Ref: 3df912344443
Ref: library/http cookies http cookies Morsel secure12344509
Ref: 3dfa12344509
Ref: library/http cookies http cookies Morsel version12344541
Ref: 3dfb12344541
Ref: library/http cookies http cookies Morsel httponly12344574
Ref: 141e12344574
Ref: library/http cookies http cookies Morsel samesite12344608
Ref: 3dfc12344608
Ref: library/http cookies http cookies Morsel value12345794
Ref: c2212345794
Ref: library/http cookies http cookies Morsel coded_value12345854
Ref: c2312345854
Ref: library/http cookies http cookies Morsel key12345960
Ref: c2112345960
Ref: library/http cookies http cookies Morsel set12346017
Ref: c2512346017
Ref: library/http cookies http cookies Morsel isReservedKey12346126
Ref: 3dfd12346126
Ref: library/http cookies http cookies Morsel output12346237
Ref: 3df312346237
Ref: library/http cookies http cookies Morsel js_output12346577
Ref: 3dfe12346577
Ref: library/http cookies http cookies Morsel OutputString12346851
Ref: 3dff12346851
Ref: library/http cookies http cookies Morsel update12347063
Ref: efd12347063
Ref: library/http cookies http cookies Morsel copy12347363
Ref: efc12347363
Ref: library/http cookies http cookies Morsel setdefault12347518
Ref: 3e0012347518
Ref: Morsel Objects-Footnote-112347734
Ref: Morsel Objects-Footnote-212347793
Ref: Morsel Objects-Footnote-312347852
Ref: Morsel Objects-Footnote-412347911
Node: Example<12>12347970
Ref: library/http cookies cookie-example12348079
Ref: 3e0112348079
Ref: library/http cookies example12348079
Ref: 3e0212348079
Node: http cookiejar — Cookie handling for HTTP clients12349717
Ref: library/http cookiejar doc12349934
Ref: 3e0312349934
Ref: library/http cookiejar http-cookiejar-cookie-handling-for-http-clients12349934
Ref: 3e0412349934
Ref: library/http cookiejar module-http cookiejar12349934
Ref: 7012349934
Ref: library/http cookiejar translation-repo12349934
Ref: 3e0512349934
Ref: library/http cookiejar http cookiejar LoadError12351491
Ref: 3e0612351491
Ref: library/http cookiejar http cookiejar CookieJar12351881
Ref: 3c2312351881
Ref: library/http cookiejar http cookiejar FileCookieJar12352343
Ref: 3e0712352343
Ref: library/http cookiejar http cookiejar CookiePolicy12353181
Ref: 3e0812353181
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy12353341
Ref: 1ba212353341
Ref: library/http cookiejar http cookiejar Cookie12355139
Ref: 3e0d12355139
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-112356808
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-212356882
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-312356941
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-412357000
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-512357059
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-612357118
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-712357177
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-812357236
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-912357295
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-1012357354
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-1112357414
Ref: http cookiejar — Cookie handling for HTTP clients-Footnote-1212357474
Node: CookieJar and FileCookieJar Objects12357534
Ref: library/http cookiejar cookie-jar-objects12357725
Ref: 3e0e12357725
Ref: library/http cookiejar cookiejar-and-filecookiejar-objects12357725
Ref: 3e0f12357725
Ref: library/http cookiejar http cookiejar CookieJar add_cookie_header12358001
Ref: 3e1012358001
Ref: library/http cookiejar http cookiejar CookieJar extract_cookies12358919
Ref: 3e1112358919
Ref: library/http cookiejar http cookiejar CookieJar set_policy12360153
Ref: 3e1312360153
Ref: library/http cookiejar http cookiejar CookieJar make_cookies12360257
Ref: 3e1412360257
Ref: library/http cookiejar http cookiejar CookieJar set_cookie_if_ok12360544
Ref: 3e1512360544
Ref: library/http cookiejar http cookiejar CookieJar set_cookie12360669
Ref: 3e1612360669
Ref: library/http cookiejar http cookiejar CookieJar clear12360818
Ref: 3e1712360818
Ref: library/http cookiejar http cookiejar CookieJar clear_session_cookies12361323
Ref: 3e1812361323
Ref: library/http cookiejar http cookiejar FileCookieJar save12361966
Ref: 3e1912361966
Ref: library/http cookiejar http cookiejar FileCookieJar load12362819
Ref: 3e0912362819
Ref: library/http cookiejar http cookiejar FileCookieJar revert12363387
Ref: 3e0a12363387
Ref: library/http cookiejar http cookiejar FileCookieJar filename12363774
Ref: 3e1a12363774
Ref: library/http cookiejar http cookiejar FileCookieJar delayload12363911
Ref: 3e1b12363911
Node: FileCookieJar subclasses and co-operation with web browsers12364332
Ref: library/http cookiejar file-cookie-jar-classes12364552
Ref: 3e0b12364552
Ref: library/http cookiejar filecookiejar-subclasses-and-co-operation-with-web-browsers12364552
Ref: 3e1c12364552
Ref: library/http cookiejar http cookiejar MozillaCookieJar12364780
Ref: 3e1d12364780
Ref: library/http cookiejar http cookiejar LWPCookieJar12365591
Ref: 3e1e12365591
Ref: FileCookieJar subclasses and co-operation with web browsers-Footnote-112366074
Node: CookiePolicy Objects12366133
Ref: library/http cookiejar cookie-policy-objects12366345
Ref: 3e1f12366345
Ref: library/http cookiejar cookiepolicy-objects12366345
Ref: 3e2012366345
Ref: library/http cookiejar http cookiejar CookiePolicy set_ok12366498
Ref: 3e1212366498
Ref: library/http cookiejar http cookiejar CookiePolicy return_ok12366824
Ref: 3e2112366824
Ref: library/http cookiejar http cookiejar CookiePolicy domain_return_ok12367153
Ref: 3e2212367153
Ref: library/http cookiejar http cookiejar CookiePolicy path_return_ok12368478
Ref: 3e2312368478
Ref: library/http cookiejar http cookiejar CookiePolicy netscape12368930
Ref: 3e2412368930
Ref: library/http cookiejar http cookiejar CookiePolicy rfc296512369003
Ref: 3e2512369003
Ref: library/http cookiejar http cookiejar CookiePolicy hide_cookie212369078
Ref: 3e2612369078
Ref: CookiePolicy Objects-Footnote-112369622
Ref: CookiePolicy Objects-Footnote-212369681
Node: DefaultCookiePolicy Objects12369740
Ref: library/http cookiejar default-cookie-policy-objects12369910
Ref: 3e2712369910
Ref: library/http cookiejar defaultcookiepolicy-objects12369910
Ref: 3e2812369910
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy blocked_domains12372229
Ref: 3e2912372229
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy set_blocked_domains12372340
Ref: 3e2a12372340
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy is_blocked12372454
Ref: 3e2b12372454
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy allowed_domains12372602
Ref: 3e2c12372602
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy set_allowed_domains12372738
Ref: 3e2d12372738
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy is_not_allowed12372872
Ref: 3e2e12372872
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy rfc2109_as_netscape12373212
Ref: 3e0c12373212
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_domain12373799
Ref: 3e2f12373799
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_rfc2965_unverifiable12374103
Ref: 3e3012374103
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_ns_unverifiable12374481
Ref: 3e3112374481
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_ns_domain12374630
Ref: 3e3212374630
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_ns_set_initial_dollar12374811
Ref: 3e3312374811
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy strict_ns_set_path12374966
Ref: 3e3412374966
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy DomainStrictNoDots12375297
Ref: 3e3512375297
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy DomainStrictNonDomain12375542
Ref: 3e3612375542
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy DomainRFC2965Match12375890
Ref: 3e3712375890
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy DomainLiberal12376127
Ref: 3e3812376127
Ref: library/http cookiejar http cookiejar DefaultCookiePolicy DomainStrict12376275
Ref: 3e3912376275
Ref: DefaultCookiePolicy Objects-Footnote-112376428
Ref: DefaultCookiePolicy Objects-Footnote-212376487
Ref: DefaultCookiePolicy Objects-Footnote-312376546
Ref: DefaultCookiePolicy Objects-Footnote-412376605
Ref: DefaultCookiePolicy Objects-Footnote-512376664
Ref: DefaultCookiePolicy Objects-Footnote-612376723
Ref: DefaultCookiePolicy Objects-Footnote-712376782
Node: Cookie Objects<2>12376841
Ref: library/http cookiejar cookie-objects12377003
Ref: 3e3a12377003
Ref: library/http cookiejar http cookiejar Cookie version12377767
Ref: 3e3b12377767
Ref: library/http cookiejar http cookiejar Cookie name12378113
Ref: 3e3c12378113
Ref: library/http cookiejar http cookiejar Cookie value12378171
Ref: 3e3d12378171
Ref: library/http cookiejar http cookiejar Cookie port12378251
Ref: 3e3e12378251
Ref: library/http cookiejar http cookiejar Cookie domain12378390
Ref: 3e3f12378390
Ref: library/http cookiejar http cookiejar Cookie path12378452
Ref: 3e4012378452
Ref: library/http cookiejar http cookiejar Cookie secure12378547
Ref: 3e4112378547
Ref: library/http cookiejar http cookiejar Cookie expires12378654
Ref: 3e4212378654
Ref: library/http cookiejar http cookiejar Cookie discard12378807
Ref: 3e4412378807
Ref: library/http cookiejar http cookiejar Cookie comment12378884
Ref: 3e4512378884
Ref: library/http cookiejar http cookiejar Cookie comment_url12379017
Ref: 3e4612379017
Ref: library/http cookiejar http cookiejar Cookie rfc210912379164
Ref: 3e4712379164
Ref: library/http cookiejar http cookiejar Cookie port_specified12379564
Ref: 3e4812379564
Ref: library/http cookiejar http cookiejar Cookie domain_specified12379743
Ref: 3e4912379743
Ref: library/http cookiejar http cookiejar Cookie domain_initial_dot12379852
Ref: 3e4a12379852
Ref: library/http cookiejar http cookiejar Cookie has_nonstandard_attr12380108
Ref: 3e4b12380108
Ref: library/http cookiejar http cookiejar Cookie get_nonstandard_attr12380222
Ref: 3e4c12380222
Ref: library/http cookiejar http cookiejar Cookie set_nonstandard_attr12380384
Ref: 3e4d12380384
Ref: library/http cookiejar http cookiejar Cookie is_expired12380556
Ref: 3e4312380556
Ref: Cookie Objects<2>-Footnote-112380849
Ref: Cookie Objects<2>-Footnote-212380908
Ref: Cookie Objects<2>-Footnote-312380967
Ref: Cookie Objects<2>-Footnote-412381026
Node: Examples<29>12381085
Ref: library/http cookiejar examples12381211
Ref: 3e4e12381211
Ref: Examples<29>-Footnote-112382659
Node: xmlrpc — XMLRPC server and client modules12382718
Ref: library/xmlrpc doc12382936
Ref: 3e4f12382936
Ref: library/xmlrpc module-xmlrpc12382936
Ref: 12d12382936
Ref: library/xmlrpc translation-repo12382936
Ref: 3e5012382936
Ref: library/xmlrpc xmlrpc-xmlrpc-server-and-client-modules12382936
Ref: 3e5112382936
Node: xmlrpc client — XML-RPC client access12383438
Ref: library/xmlrpc client doc12383644
Ref: 3e5212383644
Ref: library/xmlrpc client module-xmlrpc client12383644
Ref: 12e12383644
Ref: library/xmlrpc client translation-repo12383644
Ref: 3e5312383644
Ref: library/xmlrpc client xmlrpc-client-xml-rpc-client-access12383644
Ref: 3e5412383644
Ref: library/xmlrpc client xmlrpc client ServerProxy12384722
Ref: a6512384722
Ref: xmlrpc client — XML-RPC client access-Footnote-112392634
Ref: xmlrpc client — XML-RPC client access-Footnote-212392707
Ref: xmlrpc client — XML-RPC client access-Footnote-312392801
Ref: xmlrpc client — XML-RPC client access-Footnote-412392857
Ref: xmlrpc client — XML-RPC client access-Footnote-512392916
Node: ServerProxy Objects12392962
Ref: library/xmlrpc client id112393082
Ref: 3e5812393082
Ref: library/xmlrpc client serverproxy-objects12393082
Ref: 3e5912393082
Ref: library/xmlrpc client xmlrpc client ServerProxy system listMethods12393738
Ref: 3e5a12393738
Ref: library/xmlrpc client xmlrpc client ServerProxy system methodSignature12393901
Ref: 3e5b12393901
Ref: library/xmlrpc client xmlrpc client ServerProxy system methodHelp12394925
Ref: 3e5c12394925
Node: DateTime Objects12396000
Ref: library/xmlrpc client datetime-objects12396143
Ref: 3e5d12396143
Ref: library/xmlrpc client id212396143
Ref: 3e5e12396143
Ref: library/xmlrpc client xmlrpc client DateTime12396198
Ref: 143112396198
Ref: library/xmlrpc client xmlrpc client DateTime decode12396507
Ref: 3e5f12396507
Ref: library/xmlrpc client xmlrpc client DateTime encode12396604
Ref: 3e6012396604
Node: Binary Objects12397681
Ref: library/xmlrpc client binary-objects12397818
Ref: 3e6112397818
Ref: library/xmlrpc client id312397818
Ref: 3e6212397818
Ref: library/xmlrpc client xmlrpc client Binary12397869
Ref: 3e5512397869
Ref: library/xmlrpc client xmlrpc client Binary data12398079
Ref: 3e6312398079
Ref: library/xmlrpc client xmlrpc client Binary decode12398371
Ref: 3e6412398371
Ref: library/xmlrpc client xmlrpc client Binary encode12398510
Ref: 3e6512398510
Ref: Binary Objects-Footnote-112399754
Node: Fault Objects12399825
Ref: library/xmlrpc client fault-objects12399967
Ref: 3e6612399967
Ref: library/xmlrpc client id412399967
Ref: 3e6712399967
Ref: library/xmlrpc client xmlrpc client Fault12400016
Ref: 3e5612400016
Ref: library/xmlrpc client xmlrpc client Fault faultCode12400175
Ref: 3e6812400175
Ref: library/xmlrpc client xmlrpc client Fault faultString12400251
Ref: 3e6912400251
Node: ProtocolError Objects12401213
Ref: library/xmlrpc client protocol-error-objects12401358
Ref: 3e6a12401358
Ref: library/xmlrpc client protocolerror-objects12401358
Ref: 3e6b12401358
Ref: library/xmlrpc client xmlrpc client ProtocolError12401423
Ref: 3e5712401423
Ref: library/xmlrpc client xmlrpc client ProtocolError url12401693
Ref: 3e6c12401693
Ref: library/xmlrpc client xmlrpc client ProtocolError errcode12401770
Ref: 3e6d12401770
Ref: library/xmlrpc client xmlrpc client ProtocolError errmsg12401826
Ref: 3e6e12401826
Ref: library/xmlrpc client xmlrpc client ProtocolError headers12401905
Ref: 3e6f12401905
Node: MultiCall Objects12402645
Ref: library/xmlrpc client multicall-objects12402798
Ref: 3e7012402798
Ref: library/xmlrpc client xmlrpc client MultiCall12402981
Ref: 3e7112402981
Ref: MultiCall Objects-Footnote-112404681
Node: Convenience Functions12404860
Ref: library/xmlrpc client convenience-functions12405015
Ref: 3e7212405015
Ref: library/xmlrpc client xmlrpc client dumps12405080
Ref: 3e7312405080
Ref: library/xmlrpc client xmlrpc client loads12405792
Ref: 148312405792
Node: Example of Client Usage12406660
Ref: library/xmlrpc client example-of-client-usage12406832
Ref: 3e7412406832
Ref: library/xmlrpc client xmlrpc-client-example12406832
Ref: 3e7512406832
Node: Example of Client and Server Usage12408139
Ref: library/xmlrpc client example-of-client-and-server-usage12408281
Ref: 3e7612408281
Node: xmlrpc server — Basic XML-RPC servers12408417
Ref: library/xmlrpc server doc12408624
Ref: 3e7812408624
Ref: library/xmlrpc server module-xmlrpc server12408624
Ref: 12f12408624
Ref: library/xmlrpc server translation-repo12408624
Ref: 3e7912408624
Ref: library/xmlrpc server xmlrpc-server-basic-xml-rpc-servers12408624
Ref: 3e7a12408624
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCServer12409451
Ref: 3e7b12409451
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler12410975
Ref: 3e7c12410975
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCRequestHandler12411626
Ref: 137112411626
Ref: xmlrpc server — Basic XML-RPC servers-Footnote-112412114
Node: SimpleXMLRPCServer objects12412187
Ref: library/xmlrpc server simple-xmlrpc-servers12412321
Ref: 3e7d12412321
Ref: library/xmlrpc server simplexmlrpcserver-objects12412321
Ref: 3e7e12412321
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCServer register_function12412557
Ref: 3e7f12412557
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCServer register_instance12413306
Ref: 3e8012413306
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCServer register_introspection_functions12414922
Ref: 3e8112414922
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCServer register_multicall_functions12415131
Ref: 3e8212415131
Ref: library/xmlrpc server xmlrpc server SimpleXMLRPCRequestHandler rpc_paths12415260
Ref: 3e8312415260
Node: SimpleXMLRPCServer example12415680
Ref: library/xmlrpc server id112415769
Ref: 3e8412415769
Ref: library/xmlrpc server simplexmlrpcserver-example12415769
Ref: 3e7712415769
Node: CGIXMLRPCRequestHandler12420281
Ref: library/xmlrpc server cgixmlrpcrequesthandler12420449
Ref: 3e8512420449
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler register_function12420633
Ref: 3e8612420633
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler register_instance12421387
Ref: 3e8712421387
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler register_introspection_functions12422272
Ref: 3e8812422272
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler register_multicall_functions12422485
Ref: 3e8912422485
Ref: library/xmlrpc server xmlrpc server CGIXMLRPCRequestHandler handle_request12422624
Ref: 3e8a12422624
Node: Documenting XMLRPC server12423211
Ref: library/xmlrpc server documenting-xmlrpc-server12423376
Ref: 3e8b12423376
Ref: library/xmlrpc server xmlrpc server DocXMLRPCServer12423704
Ref: 1b4e12423704
Ref: library/xmlrpc server xmlrpc server DocCGIXMLRPCRequestHandler12424182
Ref: 3e8c12424182
Ref: library/xmlrpc server xmlrpc server DocXMLRPCRequestHandler12424317
Ref: 3e8d12424317
Node: DocXMLRPCServer objects12424636
Ref: library/xmlrpc server doc-xmlrpc-servers12424804
Ref: 3e8e12424804
Ref: library/xmlrpc server docxmlrpcserver-objects12424804
Ref: 3e8f12424804
Ref: library/xmlrpc server xmlrpc server DocXMLRPCServer set_server_title12425241
Ref: 3e9012425241
Ref: library/xmlrpc server xmlrpc server DocXMLRPCServer set_server_name12425431
Ref: 3e9112425431
Ref: library/xmlrpc server xmlrpc server DocXMLRPCServer set_server_documentation12425653
Ref: 3e9212425653
Node: DocCGIXMLRPCRequestHandler12425909
Ref: library/xmlrpc server doccgixmlrpcrequesthandler12426043
Ref: 3e9312426043
Ref: library/xmlrpc server xmlrpc server DocCGIXMLRPCRequestHandler set_server_title12426494
Ref: 3e9412426494
Ref: library/xmlrpc server xmlrpc server DocCGIXMLRPCRequestHandler set_server_name12426695
Ref: 3e9512426695
Ref: library/xmlrpc server xmlrpc server DocCGIXMLRPCRequestHandler set_server_documentation12426928
Ref: 3e9612426928
Node: ipaddress — IPv4/IPv6 manipulation library12427195
Ref: library/ipaddress doc12427354
Ref: 3e9712427354
Ref: library/ipaddress ipaddress-ipv4-ipv6-manipulation-library12427354
Ref: 3e9812427354
Ref: library/ipaddress module-ipaddress12427354
Ref: 8012427354
Ref: library/ipaddress translation-repo12427354
Ref: 3e9912427354
Ref: ipaddress — IPv4/IPv6 manipulation library-Footnote-112428374
Node: Convenience factory functions12428443
Ref: library/ipaddress convenience-factory-functions12428574
Ref: 3e9b12428574
Ref: library/ipaddress ipaddress ip_address12428772
Ref: 3e9c12428772
Ref: library/ipaddress ipaddress ip_network12429357
Ref: 3e9d12429357
Ref: library/ipaddress ipaddress ip_interface12430060
Ref: 3e9e12430060
Node: IP Addresses12430919
Ref: library/ipaddress ip-addresses12431081
Ref: 3e9f12431081
Node: Address objects12431224
Ref: library/ipaddress address-objects12431331
Ref: 3ea012431331
Ref: library/ipaddress ipaddress IPv4Address12431763
Ref: 1fc12431763
Ref: library/ipaddress ipaddress IPv4Address version12433053
Ref: 3ea212433053
Ref: library/ipaddress ipaddress IPv4Address max_prefixlen12433161
Ref: 3ea312433161
Ref: library/ipaddress ipaddress IPv4Address compressed12433499
Ref: 3ea412433499
Ref: library/ipaddress ipaddress IPv4Address exploded12433531
Ref: 3ea512433531
Ref: library/ipaddress ipaddress IPv4Address packed12434020
Ref: 3ea612434020
Ref: library/ipaddress ipaddress IPv4Address reverse_pointer12434257
Ref: e5112434257
Ref: library/ipaddress ipaddress IPv4Address is_multicast12434804
Ref: 3ea712434804
Ref: library/ipaddress ipaddress IPv4Address is_private12434971
Ref: 175712434971
Ref: library/ipaddress ipaddress IPv4Address is_global12436621
Ref: f9812436621
Ref: library/ipaddress ipaddress IPv4Address is_unspecified12437536
Ref: 3ea912437536
Ref: library/ipaddress ipaddress IPv4Address is_reserved12437690
Ref: 3eaa12437690
Ref: library/ipaddress ipaddress IPv4Address is_loopback12438395
Ref: 3eac12438395
Ref: library/ipaddress ipaddress IPv4Address is_link_local12438548
Ref: 3ead12438548
Ref: library/ipaddress ipaddress IPv4Address ipv6_mapped12438683
Ref: 1fb12438683
Ref: library/ipaddress ipaddress IPv4Address __format__12438858
Ref: 3eae12438858
Ref: library/ipaddress ipaddress IPv6Address12440108
Ref: 1fd12440108
Ref: library/ipaddress ipaddress IPv6Address compressed12441481
Ref: 3eaf12441481
Ref: library/ipaddress ipaddress IPv6Address exploded12441790
Ref: 3eb012441790
Ref: library/ipaddress ipaddress IPv6Address packed12442078
Ref: 3eb112442078
Ref: library/ipaddress ipaddress IPv6Address reverse_pointer12442106
Ref: 16dd12442106
Ref: library/ipaddress ipaddress IPv6Address version12442143
Ref: 3eb212442143
Ref: library/ipaddress ipaddress IPv6Address max_prefixlen12442172
Ref: 3eb312442172
Ref: library/ipaddress ipaddress IPv6Address is_multicast12442207
Ref: 3eb412442207
Ref: library/ipaddress ipaddress IPv6Address is_private12442241
Ref: 175812442241
Ref: library/ipaddress ipaddress IPv6Address is_global12442273
Ref: 175912442273
Ref: library/ipaddress ipaddress IPv6Address is_unspecified12442337
Ref: 3eb512442337
Ref: library/ipaddress ipaddress IPv6Address is_reserved12442373
Ref: 3eb612442373
Ref: library/ipaddress ipaddress IPv6Address is_loopback12442406
Ref: 173d12442406
Ref: library/ipaddress ipaddress IPv6Address is_link_local12442439
Ref: 3eb712442439
Ref: library/ipaddress ipaddress IPv6Address is_site_local12442474
Ref: 3eab12442474
Ref: library/ipaddress ipaddress IPv6Address ipv4_mapped12442820
Ref: 3ea812442820
Ref: library/ipaddress ipaddress IPv6Address scope_id12443092
Ref: 91712443092
Ref: library/ipaddress ipaddress IPv6Address sixtofour12443392
Ref: 3eb812443392
Ref: library/ipaddress ipaddress IPv6Address teredo12443682
Ref: 3eb912443682
Ref: library/ipaddress ipaddress IPv6Address __format__12443996
Ref: 3eba12443996
Ref: Address objects-Footnote-112444188
Ref: Address objects-Footnote-212444247
Ref: Address objects-Footnote-312444306
Ref: Address objects-Footnote-412444408
Ref: Address objects-Footnote-512444510
Ref: Address objects-Footnote-612444612
Ref: Address objects-Footnote-712444714
Ref: Address objects-Footnote-812444773
Ref: Address objects-Footnote-912444832
Ref: Address objects-Footnote-1012444918
Ref: Address objects-Footnote-1112445021
Ref: Address objects-Footnote-1212445081
Ref: Address objects-Footnote-1312445141
Ref: Address objects-Footnote-1412445201
Ref: Address objects-Footnote-1512445261
Ref: Address objects-Footnote-1612445321
Ref: Address objects-Footnote-1712445381
Ref: Address objects-Footnote-1812445441
Ref: Address objects-Footnote-1912445501
Ref: Address objects-Footnote-2012445561
Ref: Address objects-Footnote-2112445621
Ref: Address objects-Footnote-2212445681
Node: Conversion to Strings and Integers12445741
Ref: library/ipaddress conversion-to-strings-and-integers12445869
Ref: 3ebb12445869
Node: Operators<3>12446493
Ref: library/ipaddress operators12446597
Ref: 3ebc12446597
Node: Comparison operators12446862
Ref: library/ipaddress comparison-operators12446960
Ref: 3ebd12446960
Node: Arithmetic operators12447554
Ref: library/ipaddress arithmetic-operators12447652
Ref: 3ebe12447652
Node: IP Network definitions12448155
Ref: library/ipaddress ip-network-definitions12448305
Ref: 3ebf12448305
Node: Prefix net mask and host mask12449015
Ref: library/ipaddress prefix-net-mask-and-host-mask12449127
Ref: 3ec012449127
Node: Network objects12449797
Ref: library/ipaddress network-objects12449930
Ref: 3ec112449930
Ref: library/ipaddress ipaddress IPv4Network12450383
Ref: 1fe12450383
Ref: library/ipaddress ipaddress IPv4Network version12452806
Ref: 3ec312452806
Ref: library/ipaddress ipaddress IPv4Network max_prefixlen12452835
Ref: 3ec412452835
Ref: library/ipaddress ipaddress IPv4Network is_multicast12452969
Ref: 3ec512452969
Ref: library/ipaddress ipaddress IPv4Network is_private12453003
Ref: 3ec612453003
Ref: library/ipaddress ipaddress IPv4Network is_unspecified12453035
Ref: 3ec712453035
Ref: library/ipaddress ipaddress IPv4Network is_reserved12453071
Ref: 3ec812453071
Ref: library/ipaddress ipaddress IPv4Network is_loopback12453104
Ref: 3ec912453104
Ref: library/ipaddress ipaddress IPv4Network is_link_local12453137
Ref: 3eca12453137
Ref: library/ipaddress ipaddress IPv4Network network_address12453329
Ref: 3ecb12453329
Ref: library/ipaddress ipaddress IPv4Network broadcast_address12453503
Ref: 3ecc12453503
Ref: library/ipaddress ipaddress IPv4Network hostmask12453700
Ref: 3ecd12453700
Ref: library/ipaddress ipaddress IPv4Network netmask12453794
Ref: 3ece12453794
Ref: library/ipaddress ipaddress IPv4Network with_prefixlen12453886
Ref: 3ecf12453886
Ref: library/ipaddress ipaddress IPv4Network compressed12453922
Ref: 3ed012453922
Ref: library/ipaddress ipaddress IPv4Network exploded12453954
Ref: 3ed112453954
Ref: library/ipaddress ipaddress IPv4Network with_netmask12454255
Ref: 3ed212454255
Ref: library/ipaddress ipaddress IPv4Network with_hostmask12454386
Ref: 3ed312454386
Ref: library/ipaddress ipaddress IPv4Network num_addresses12454519
Ref: 3ed412454519
Ref: library/ipaddress ipaddress IPv4Network prefixlen12454611
Ref: 3ed512454611
Ref: library/ipaddress ipaddress IPv4Network hosts12454692
Ref: 15f612454692
Ref: library/ipaddress ipaddress IPv4Network overlaps12455689
Ref: 3ed612455689
Ref: library/ipaddress ipaddress IPv4Network address_exclude12455861
Ref: 3ed712455861
Ref: library/ipaddress ipaddress IPv4Network subnets12456467
Ref: ed412456467
Ref: library/ipaddress ipaddress IPv4Network supernet12458015
Ref: ed512458015
Ref: library/ipaddress ipaddress IPv4Network subnet_of12458821
Ref: 3ed812458821
Ref: library/ipaddress ipaddress IPv4Network supernet_of12459120
Ref: 3ed912459120
Ref: library/ipaddress ipaddress IPv4Network compare_networks12459425
Ref: 3eda12459425
Ref: library/ipaddress ipaddress IPv6Network12460123
Ref: 1ff12460123
Ref: library/ipaddress ipaddress IPv6Network version12461930
Ref: 3edb12461930
Ref: library/ipaddress ipaddress IPv6Network max_prefixlen12461959
Ref: 3edc12461959
Ref: library/ipaddress ipaddress IPv6Network is_multicast12461994
Ref: 3edd12461994
Ref: library/ipaddress ipaddress IPv6Network is_private12462028
Ref: 3ede12462028
Ref: library/ipaddress ipaddress IPv6Network is_unspecified12462060
Ref: 3edf12462060
Ref: library/ipaddress ipaddress IPv6Network is_reserved12462096
Ref: 3ee012462096
Ref: library/ipaddress ipaddress IPv6Network is_loopback12462129
Ref: 3ee112462129
Ref: library/ipaddress ipaddress IPv6Network is_link_local12462162
Ref: 3ee212462162
Ref: library/ipaddress ipaddress IPv6Network network_address12462197
Ref: 3ee312462197
Ref: library/ipaddress ipaddress IPv6Network broadcast_address12462234
Ref: 3ee412462234
Ref: library/ipaddress ipaddress IPv6Network hostmask12462273
Ref: 3ee512462273
Ref: library/ipaddress ipaddress IPv6Network netmask12462303
Ref: 3ee612462303
Ref: library/ipaddress ipaddress IPv6Network with_prefixlen12462332
Ref: 3ee712462332
Ref: library/ipaddress ipaddress IPv6Network compressed12462368
Ref: 3ee812462368
Ref: library/ipaddress ipaddress IPv6Network exploded12462400
Ref: 3ee912462400
Ref: library/ipaddress ipaddress IPv6Network with_netmask12462430
Ref: 3eea12462430
Ref: library/ipaddress ipaddress IPv6Network with_hostmask12462464
Ref: 3eeb12462464
Ref: library/ipaddress ipaddress IPv6Network num_addresses12462499
Ref: 3eec12462499
Ref: library/ipaddress ipaddress IPv6Network prefixlen12462534
Ref: 3eed12462534
Ref: library/ipaddress ipaddress IPv6Network hosts12462565
Ref: 15f712462565
Ref: library/ipaddress ipaddress IPv6Network overlaps12463015
Ref: 3eee12463015
Ref: library/ipaddress ipaddress IPv6Network address_exclude12463050
Ref: 3eef12463050
Ref: library/ipaddress ipaddress IPv6Network subnets12463094
Ref: 3ef012463094
Ref: library/ipaddress ipaddress IPv6Network supernet12463156
Ref: 3ef112463156
Ref: library/ipaddress ipaddress IPv6Network subnet_of12463219
Ref: 3ef212463219
Ref: library/ipaddress ipaddress IPv6Network supernet_of12463255
Ref: 3ef312463255
Ref: library/ipaddress ipaddress IPv6Network compare_networks12463293
Ref: 3ef412463293
Ref: library/ipaddress ipaddress IPv6Network is_site_local12463435
Ref: 3ef512463435
Node: Operators<4>12463612
Ref: library/ipaddress id112463707
Ref: 3ef612463707
Node: Logical operators12464000
Ref: library/ipaddress logical-operators12464084
Ref: 3ef712464084
Node: Iteration12464289
Ref: library/ipaddress iteration12464417
Ref: 3ef812464417
Node: Networks as containers of addresses12465245
Ref: library/ipaddress networks-as-containers-of-addresses12465347
Ref: 3ef912465347
Node: Interface objects12465805
Ref: library/ipaddress interface-objects12465971
Ref: 3efa12465971
Ref: library/ipaddress ipaddress IPv4Interface12466119
Ref: 193f12466119
Ref: library/ipaddress ipaddress IPv4Interface ip12466528
Ref: 3efb12466528
Ref: library/ipaddress ipaddress IPv4Interface network12466774
Ref: 3efc12466774
Ref: library/ipaddress ipaddress IPv4Interface with_prefixlen12467031
Ref: 3efd12467031
Ref: library/ipaddress ipaddress IPv4Interface with_netmask12467299
Ref: 3efe12467299
Ref: library/ipaddress ipaddress IPv4Interface with_hostmask12467572
Ref: 3eff12467572
Ref: library/ipaddress ipaddress IPv6Interface12467844
Ref: 194012467844
Ref: library/ipaddress ipaddress IPv6Interface ip12468253
Ref: 3f0012468253
Ref: library/ipaddress ipaddress IPv6Interface network12468277
Ref: 3f0112468277
Ref: library/ipaddress ipaddress IPv6Interface with_prefixlen12468306
Ref: 3f0212468306
Ref: library/ipaddress ipaddress IPv6Interface with_netmask12468342
Ref: 3f0312468342
Ref: library/ipaddress ipaddress IPv6Interface with_hostmask12468376
Ref: 3f0412468376
Node: Operators<5>12468550
Ref: library/ipaddress id212468616
Ref: 3f0512468616
Node: Logical operators<2>12468878
Ref: library/ipaddress id312468947
Ref: 3f0612468947
Node: Other Module Level Functions12469604
Ref: library/ipaddress other-module-level-functions12469765
Ref: 3f0712469765
Ref: library/ipaddress ipaddress v4_int_to_packed12469910
Ref: 3f0812469910
Ref: library/ipaddress ipaddress v6_int_to_packed12470384
Ref: 3f0912470384
Ref: library/ipaddress ipaddress summarize_address_range12470693
Ref: ed612470693
Ref: library/ipaddress ipaddress collapse_addresses12471560
Ref: ed712471560
Ref: library/ipaddress ipaddress get_mixed_type_key12472129
Ref: 3f0a12472129
Node: Custom Exceptions12472723
Ref: library/ipaddress custom-exceptions12472858
Ref: 3f0b12472858
Ref: library/ipaddress ipaddress AddressValueError12473029
Ref: 3ea112473029
Ref: library/ipaddress ipaddress NetmaskValueError12473132
Ref: 3ec212473132
Node: Multimedia Services12473236
Ref: library/mm doc12473387
Ref: 3f0c12473387
Ref: library/mm mmedia12473387
Ref: 3f0d12473387
Ref: library/mm multimedia-services12473387
Ref: 3f0e12473387
Ref: library/mm translation-repo12473387
Ref: 3f0f12473387
Node: wave — Read and write WAV files12473753
Ref: library/wave doc12473897
Ref: 3f1012473897
Ref: library/wave module-wave12473897
Ref: 11312473897
Ref: library/wave wave-read-and-write-wav-files12473897
Ref: 3f1112473897
Ref: library/wave wave open12474482
Ref: 95512474482
Ref: library/wave wave Error12475533
Ref: 3f1412475533
Ref: wave — Read and write WAV files-Footnote-112475787
Node: Wave_read Objects12475851
Ref: library/wave id112475965
Ref: 3f1512475965
Ref: library/wave wave-read-objects12475965
Ref: 3f1612475965
Ref: library/wave wave Wave_read12476020
Ref: 2b612476020
Ref: library/wave wave Wave_read close12476162
Ref: 3f1212476162
Ref: library/wave wave Wave_read getnchannels12476353
Ref: 3f1712476353
Ref: library/wave wave Wave_read getsampwidth12476481
Ref: 3f1812476481
Ref: library/wave wave Wave_read getframerate12476557
Ref: 3f1912476557
Ref: library/wave wave Wave_read getnframes12476630
Ref: 3f1a12476630
Ref: library/wave wave Wave_read getcomptype12476705
Ref: 3f1b12476705
Ref: library/wave wave Wave_read getcompname12476827
Ref: 3f1c12476827
Ref: library/wave wave Wave_read getparams12476990
Ref: 102512476990
Ref: library/wave wave Wave_read readframes12477207
Ref: 3f1d12477207
Ref: library/wave wave Wave_read rewind12477339
Ref: 3f1e12477339
Ref: library/wave wave Wave_read getmarkers12477576
Ref: 2b512477576
Ref: library/wave wave Wave_read getmark12477842
Ref: 2b412477842
Ref: library/wave wave Wave_read setpos12478246
Ref: 3f1f12478246
Ref: library/wave wave Wave_read tell12478336
Ref: 3f2012478336
Node: Wave_write Objects12478411
Ref: library/wave id212478525
Ref: 3f2112478525
Ref: library/wave wave-write-objects12478525
Ref: 102612478525
Ref: library/wave wave Wave_write12478582
Ref: 2b712478582
Ref: library/wave wave Wave_write close12479609
Ref: 3f1312479609
Ref: library/wave wave Wave_write setnchannels12479950
Ref: 3f2412479950
Ref: library/wave wave Wave_write getnchannels12480024
Ref: 3f2512480024
Ref: library/wave wave Wave_write setsampwidth12480100
Ref: 3f2612480100
Ref: library/wave wave Wave_write getsampwidth12480181
Ref: 3f2712480181
Ref: library/wave wave Wave_write setframerate12480260
Ref: 3f2812480260
Ref: library/wave wave Wave_write getframerate12480449
Ref: 3f2912480449
Ref: library/wave wave Wave_write setnframes12480517
Ref: 3f2212480517
Ref: library/wave wave Wave_write getnframes12480786
Ref: 3f2a12480786
Ref: library/wave wave Wave_write setcomptype12480879
Ref: 3f2b12480879
Ref: library/wave wave Wave_write getcomptype12481072
Ref: 3f2c12481072
Ref: library/wave wave Wave_write getcompname12481160
Ref: 3f2d12481160
Ref: library/wave wave Wave_write setparams12481253
Ref: 3f2312481253
Ref: library/wave wave Wave_write getparams12481482
Ref: 3f2e12481482
Ref: library/wave wave Wave_write tell12481689
Ref: 3f2f12481689
Ref: library/wave wave Wave_write writeframesraw12481891
Ref: 102712481891
Ref: library/wave wave Wave_write writeframes12482088
Ref: 102812482088
Node: colorsys — Conversions between color systems12482731
Ref: library/colorsys doc12482875
Ref: 3f3012482875
Ref: library/colorsys colorsys-conversions-between-color-systems12482875
Ref: 3f3112482875
Ref: library/colorsys module-colorsys12482875
Ref: 1f12482875
Ref: library/colorsys translation-repo12482875
Ref: 3f3212482875
Ref: library/colorsys colorsys rgb_to_yiq12483853
Ref: 3f3312483853
Ref: library/colorsys colorsys yiq_to_rgb12483963
Ref: 3f3412483963
Ref: library/colorsys colorsys rgb_to_hls12484073
Ref: 181112484073
Ref: library/colorsys colorsys hls_to_rgb12484183
Ref: 3f3512484183
Ref: library/colorsys colorsys rgb_to_hsv12484293
Ref: 3f3612484293
Ref: library/colorsys colorsys hsv_to_rgb12484403
Ref: 3f3712484403
Ref: colorsys — Conversions between color systems-Footnote-112484715
Node: Internationalization12484783
Ref: library/i18n doc12484937
Ref: 3f3812484937
Ref: library/i18n i18n12484937
Ref: 3f3912484937
Ref: library/i18n internationalization12484937
Ref: 3f3a12484937
Ref: library/i18n translation-repo12484937
Ref: 3f3b12484937
Node: gettext — Multilingual internationalization services12485392
Ref: library/gettext doc12485552
Ref: 3f3c12485552
Ref: library/gettext gettext-multilingual-internationalization-services12485552
Ref: 3f3d12485552
Ref: library/gettext module-gettext12485552
Ref: 6312485552
Ref: gettext — Multilingual internationalization services-Footnote-112486524
Node: GNU gettext API12486591
Ref: library/gettext gnu-gettext-api12486721
Ref: 3f3e12486721
Ref: library/gettext gettext bindtextdomain12487260
Ref: 3f3f12487260
Ref: library/gettext gettext textdomain12487827
Ref: 3f4012487827
Ref: library/gettext gettext gettext12488073
Ref: 14b812488073
Ref: library/gettext gettext dgettext12488342
Ref: 3f4112488342
Ref: library/gettext gettext ngettext12488482
Ref: 3f4212488482
Ref: library/gettext gettext dngettext12489193
Ref: 3f4312489193
Ref: library/gettext gettext pgettext12489347
Ref: a0012489347
Ref: library/gettext gettext dpgettext12489398
Ref: 3f4412489398
Ref: library/gettext gettext npgettext12489458
Ref: 3f4512489458
Ref: library/gettext gettext dnpgettext12489522
Ref: 3f4612489522
Ref: GNU gettext API-Footnote-112490341
Ref: GNU gettext API-Footnote-212490821
Node: Class-based API12490886
Ref: library/gettext class-based-api12491069
Ref: 3f4712491069
Ref: library/gettext gettext find12491594
Ref: 3f4912491594
Ref: library/gettext gettext translation12493025
Ref: a8812493025
Ref: library/gettext gettext install12494264
Ref: a8912494264
Ref: Class-based API-Footnote-112495299
Node: The NullTranslations class12495365
Ref: library/gettext the-nulltranslations-class12495477
Ref: 3f4c12495477
Ref: library/gettext gettext NullTranslations12495922
Ref: 3f4a12495922
Ref: library/gettext gettext NullTranslations _parse12496322
Ref: 3f4e12496322
Ref: library/gettext gettext NullTranslations add_fallback12496633
Ref: 3f4d12496633
Ref: library/gettext gettext NullTranslations gettext12496896
Ref: 3f4f12496896
Ref: library/gettext gettext NullTranslations ngettext12497094
Ref: 3f5012497094
Ref: library/gettext gettext NullTranslations pgettext12497346
Ref: 3f5112497346
Ref: library/gettext gettext NullTranslations npgettext12497600
Ref: 3f5212497600
Ref: library/gettext gettext NullTranslations info12497868
Ref: 3f5312497868
Ref: library/gettext gettext NullTranslations charset12497994
Ref: 3f5412497994
Ref: library/gettext gettext NullTranslations install12498083
Ref: 3f4b12498083
Node: The GNUTranslations class12499275
Ref: library/gettext the-gnutranslations-class12499427
Ref: 3f5512499427
Ref: library/gettext gettext GNUTranslations12500932
Ref: 3f4812500932
Ref: library/gettext gettext GNUTranslations gettext12501052
Ref: 3f5612501052
Ref: library/gettext gettext GNUTranslations ngettext12501461
Ref: 3f5712501461
Ref: library/gettext gettext GNUTranslations pgettext12502385
Ref: 3f5812502385
Ref: library/gettext gettext GNUTranslations npgettext12502858
Ref: 3f5912502858
Ref: The GNUTranslations class-Footnote-112503500
Node: Solaris message catalog support12503558
Ref: library/gettext solaris-message-catalog-support12503707
Ref: 3f5a12503707
Node: The Catalog constructor12503956
Ref: library/gettext the-catalog-constructor12504071
Ref: 3f5b12504071
Node: Internationalizing your programs and modules12504724
Ref: library/gettext i18n-howto12504911
Ref: 30c012504911
Ref: library/gettext internationalizing-your-programs-and-modules12504911
Ref: 3f5c12504911
Ref: Internationalizing your programs and modules-Footnote-112508476
Ref: Internationalizing your programs and modules-Footnote-212508509
Node: Localizing your module12508552
Ref: library/gettext localizing-your-module12508691
Ref: 3f5d12508691
Node: Localizing your application12509286
Ref: library/gettext localizing-your-application12509463
Ref: 3f5e12509463
Node: Changing languages on the fly12510191
Ref: library/gettext changing-languages-on-the-fly12510367
Ref: 3f5f12510367
Node: Deferred translations12511046
Ref: library/gettext deferred-translations12511186
Ref: 3f6012511186
Node: Acknowledgements<9>12513426
Ref: library/gettext acknowledgements12513589
Ref: 3f6112513589
Node: locale — Internationalization services12513985
Ref: library/locale doc12514145
Ref: 3f6212514145
Ref: library/locale locale-internationalization-services12514145
Ref: 3f6312514145
Ref: library/locale module-locale12514145
Ref: 8612514145
Ref: library/locale translation-repo12514145
Ref: 3f6412514145
Ref: library/locale locale Error12514858
Ref: 3f6512514858
Ref: library/locale locale setlocale12514984
Ref: 2db12514984
Ref: library/locale locale localeconv12516894
Ref: c1e12516894
Ref: library/locale locale nl_langinfo12525195
Ref: 3f6a12525195
Ref: library/locale locale CODESET12525708
Ref: 3f6b12525708
Ref: library/locale locale D_T_FMT12525842
Ref: 3f6c12525842
Ref: library/locale locale D_FMT12526039
Ref: 3f6d12526039
Ref: library/locale locale T_FMT12526227
Ref: 3f6e12526227
Ref: library/locale locale T_FMT_AMPM12526415
Ref: 3f6f12526415
Ref: library/locale locale DAY_112526562
Ref: 3f7012526562
Ref: library/locale locale DAY_212526590
Ref: 3f7112526590
Ref: library/locale locale DAY_312526618
Ref: 3f7212526618
Ref: library/locale locale DAY_412526646
Ref: 3f7312526646
Ref: library/locale locale DAY_512526674
Ref: 3f7412526674
Ref: library/locale locale DAY_612526702
Ref: 3f7512526702
Ref: library/locale locale DAY_712526730
Ref: 3f7612526730
Ref: library/locale locale ABDAY_112527017
Ref: 3f7712527017
Ref: library/locale locale ABDAY_212527047
Ref: 3f7812527047
Ref: library/locale locale ABDAY_312527077
Ref: 3f7912527077
Ref: library/locale locale ABDAY_412527107
Ref: 3f7a12527107
Ref: library/locale locale ABDAY_512527137
Ref: 3f7b12527137
Ref: library/locale locale ABDAY_612527167
Ref: 3f7c12527167
Ref: library/locale locale ABDAY_712527197
Ref: 3f7d12527197
Ref: library/locale locale MON_112527293
Ref: 3f7e12527293
Ref: library/locale locale MON_212527321
Ref: 3f7f12527321
Ref: library/locale locale MON_312527349
Ref: 3f8012527349
Ref: library/locale locale MON_412527377
Ref: 3f8112527377
Ref: library/locale locale MON_512527405
Ref: 3f8212527405
Ref: library/locale locale MON_612527433
Ref: 3f8312527433
Ref: library/locale locale MON_712527461
Ref: 3f8412527461
Ref: library/locale locale MON_812527489
Ref: 3f8512527489
Ref: library/locale locale MON_912527517
Ref: 3f8612527517
Ref: library/locale locale MON_1012527545
Ref: 3f8712527545
Ref: library/locale locale MON_1112527574
Ref: 3f8812527574
Ref: library/locale locale MON_1212527603
Ref: 3f8912527603
Ref: library/locale locale ABMON_112527676
Ref: 3f8a12527676
Ref: library/locale locale ABMON_212527706
Ref: 3f8b12527706
Ref: library/locale locale ABMON_312527736
Ref: 3f8c12527736
Ref: library/locale locale ABMON_412527766
Ref: 3f8d12527766
Ref: library/locale locale ABMON_512527796
Ref: 3f8e12527796
Ref: library/locale locale ABMON_612527826
Ref: 3f8f12527826
Ref: library/locale locale ABMON_712527856
Ref: 3f9012527856
Ref: library/locale locale ABMON_812527886
Ref: 3f9112527886
Ref: library/locale locale ABMON_912527916
Ref: 3f9212527916
Ref: library/locale locale ABMON_1012527946
Ref: 3f9312527946
Ref: library/locale locale ABMON_1112527977
Ref: 3f9412527977
Ref: library/locale locale ABMON_1212528008
Ref: 3f9512528008
Ref: library/locale locale RADIXCHAR12528095
Ref: 3f9612528095
Ref: library/locale locale THOUSEP12528199
Ref: 3f9712528199
Ref: library/locale locale YESEXPR12528319
Ref: 3f9812528319
Ref: library/locale locale NOEXPR12528502
Ref: 3f9912528502
Ref: library/locale locale CRNCYSTR12528959
Ref: 3f9a12528959
Ref: library/locale locale ERA12529237
Ref: 3f9b12529237
Ref: library/locale locale ERA_D_T_FMT12530056
Ref: 3f9c12530056
Ref: library/locale locale ERA_D_FMT12530228
Ref: 3f9d12530228
Ref: library/locale locale ERA_T_FMT12530391
Ref: 3f9e12530391
Ref: library/locale locale ALT_DIGITS12530554
Ref: 3f9f12530554
Ref: library/locale locale getdefaultlocale12530789
Ref: 2d912530789
Ref: library/locale locale getlocale12532163
Ref: 2da12532163
Ref: library/locale locale getpreferredencoding12532739
Ref: 53d12532739
Ref: library/locale locale getencoding12533821
Ref: 2dc12533821
Ref: library/locale locale normalize12534595
Ref: 3fa312534595
Ref: library/locale locale strcoll12535015
Ref: 3fa412535015
Ref: library/locale locale strxfrm12535334
Ref: 161412535334
Ref: library/locale locale format_string12535678
Ref: 52212535678
Ref: library/locale locale currency12536380
Ref: 3fa612536380
Ref: library/locale locale str12537027
Ref: 3fa712537027
Ref: library/locale locale delocalize12537216
Ref: e5812537216
Ref: library/locale locale localize12537396
Ref: 3fa812537396
Ref: library/locale locale atof12537616
Ref: 3fa912537616
Ref: library/locale locale atoi12537840
Ref: 3faa12537840
Ref: library/locale locale LC_CTYPE12537971
Ref: 3fa112537971
Ref: library/locale locale LC_COLLATE12538634
Ref: 3fa512538634
Ref: library/locale locale LC_TIME12538822
Ref: 3fab12538822
Ref: library/locale locale LC_MONETARY12538973
Ref: 3f6912538973
Ref: library/locale locale LC_MESSAGES12539146
Ref: 3fac12539146
Ref: library/locale locale LC_NUMERIC12539568
Ref: 3f6712539568
Ref: library/locale locale LC_ALL12539886
Ref: 3fa012539886
Ref: library/locale locale CHAR_MAX12540311
Ref: 3f6812540311
Ref: locale — Internationalization services-Footnote-112540682
Ref: locale — Internationalization services-Footnote-212540748
Ref: locale — Internationalization services-Footnote-312540846
Ref: locale — Internationalization services-Footnote-412540888
Node: Background details hints tips and caveats12540930
Ref: library/locale background-details-hints-tips-and-caveats12541069
Ref: 3fad12541069
Node: Locale names12543276
Ref: library/locale locale-name12543476
Ref: 3f6612543476
Ref: library/locale locale-names12543476
Ref: 3fae12543476
Ref: Locale names-Footnote-112545146
Ref: Locale names-Footnote-212545296
Ref: Locale names-Footnote-312545346
Ref: Locale names-Footnote-412545402
Ref: Locale names-Footnote-512545575
Ref: Locale names-Footnote-612545664
Ref: Locale names-Footnote-712545710
Node: For extension writers and programs that embed Python12545752
Ref: library/locale embedding-locale12545937
Ref: 3faf12545937
Ref: library/locale for-extension-writers-and-programs-that-embed-python12545937
Ref: 3fb012545937
Node: Access to message catalogs12546729
Ref: library/locale access-to-message-catalogs12546893
Ref: 3fb112546893
Ref: library/locale locale-gettext12546893
Ref: 3fb212546893
Ref: library/locale locale gettext12546966
Ref: 3fb312546966
Ref: library/locale locale dgettext12547002
Ref: 3fb412547002
Ref: library/locale locale dcgettext12547047
Ref: 3fb512547047
Ref: library/locale locale textdomain12547103
Ref: 3fb612547103
Ref: library/locale locale bindtextdomain12547145
Ref: 3fb712547145
Ref: library/locale locale bind_textdomain_codeset12547196
Ref: 3fb812547196
Node: Graphical user interfaces with Tk12548183
Ref: library/tk doc12548335
Ref: 3fb912548335
Ref: library/tk graphical-user-interfaces-with-tk12548335
Ref: 3fba12548335
Ref: library/tk tkinter12548335
Ref: 3fbb12548335
Ref: library/tk translation-repo12548335
Ref: 3fbc12548335
Ref: Graphical user interfaces with Tk-Footnote-112550218
Node: tkinter — Python interface to Tcl/Tk12550270
Ref: library/tkinter doc12550433
Ref: 3fbd12550433
Ref: library/tkinter module-tkinter12550433
Ref: f012550433
Ref: library/tkinter tkinter-python-interface-to-tcl-tk12550433
Ref: 3fbe12550433
Ref: tkinter — Python interface to Tcl/Tk-Footnote-112553305
Ref: tkinter — Python interface to Tcl/Tk-Footnote-212553382
Ref: tkinter — Python interface to Tcl/Tk-Footnote-312553410
Ref: tkinter — Python interface to Tcl/Tk-Footnote-412553450
Ref: tkinter — Python interface to Tcl/Tk-Footnote-512553507
Ref: tkinter — Python interface to Tcl/Tk-Footnote-612553534
Ref: tkinter — Python interface to Tcl/Tk-Footnote-712553571
Ref: tkinter — Python interface to Tcl/Tk-Footnote-812553669
Ref: tkinter — Python interface to Tcl/Tk-Footnote-912553721
Node: Architecture12553780
Ref: library/tkinter architecture12553891
Ref: 3fbf12553891
Ref: Architecture-Footnote-112556217
Node: Tkinter Modules12556257
Ref: library/tkinter tkinter-modules12556399
Ref: 3fc112556399
Ref: library/tkinter tkinter Tk12556721
Ref: 173f12556721
Ref: library/tkinter tkinter Tk tk12558849
Ref: 3fc312558849
Ref: library/tkinter tkinter Tk master12559135
Ref: 3fc412559135
Ref: library/tkinter tkinter Tk children12559715
Ref: 3fc512559715
Ref: library/tkinter tkinter Tcl12559925
Ref: 3fc212559925
Ref: library/tkinter module-_tkinter12561500
Ref: 312561500
Node: Tkinter Life Preserver12562394
Ref: library/tkinter tkinter-life-preserver12562539
Ref: 3fc612562539
Node: A Hello World Program12563367
Ref: library/tkinter a-hello-world-program12563477
Ref: 3fc712563477
Node: Important Tk Concepts12564942
Ref: library/tkinter important-tk-concepts12565099
Ref: 3fc812565099
Node: Understanding How Tkinter Wraps Tcl/Tk12566447
Ref: library/tkinter understanding-how-tkinter-wraps-tcl-tk12566616
Ref: 3fc912566616
Node: How do I…? What option does…?12568765
Ref: library/tkinter how-do-i-what-option-does12568951
Ref: 3fca12568951
Node: Navigating the Tcl/Tk Reference Manual12570697
Ref: library/tkinter navigating-the-tcl-tk-reference-manual12570836
Ref: 3fcb12570836
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-112572914
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-212572971
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-312573030
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-412573083
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-512573139
Ref: Navigating the Tcl/Tk Reference Manual-Footnote-612573198
Node: Threading model12573252
Ref: library/tkinter threading-model12573397
Ref: 3fc012573397
Node: Handy Reference12576374
Ref: library/tkinter handy-reference12576510
Ref: 3fcc12576510
Node: Setting Options12576764
Ref: library/tkinter setting-options12576850
Ref: 3fcd12576850
Ref: library/tkinter tkinter-setting-options12576850
Ref: 3fce12576850
Ref: Setting Options-Footnote-112580098
Node: The Packer12580145
Ref: library/tkinter the-packer12580254
Ref: 3fcf12580254
Node: Packer Options12581888
Ref: library/tkinter packer-options12582007
Ref: 3fd012582007
Node: Coupling Widget Variables12582699
Ref: library/tkinter coupling-widget-variables12582826
Ref: 3fd112582826
Node: The Window Manager12585017
Ref: library/tkinter the-window-manager12585150
Ref: 3fd212585150
Node: Tk Option Data Types12586552
Ref: library/tkinter tk-option-data-types12586679
Ref: 3fd312586679
Node: Bindings and Events12589722
Ref: library/tkinter bindings-and-events12589850
Ref: 3fd412589850
Ref: library/tkinter id212589850
Ref: 3fd512589850
Ref: Bindings and Events-Footnote-112592682
Node: The index Parameter12592728
Ref: library/tkinter the-index-parameter12592842
Ref: 3fd612592842
Node: Images12594771
Ref: library/tkinter images12594857
Ref: 3fd712594857
Ref: Images-Footnote-112596155
Node: File Handlers12596190
Ref: library/tkinter file-handlers12596302
Ref: 3fd812596302
Ref: library/tkinter tkinter-file-handlers12596302
Ref: 3fd912596302
Ref: library/tkinter tkinter Widget tk createfilehandler12597244
Ref: 3fda12597244
Ref: library/tkinter tkinter Widget tk deletefilehandler12597679
Ref: 3fdb12597679
Ref: library/tkinter tkinter READABLE12597761
Ref: 3fdc12597761
Ref: library/tkinter tkinter WRITABLE12597789
Ref: 3fdd12597789
Ref: library/tkinter tkinter EXCEPTION12597817
Ref: 3fde12597817
Node: tkinter colorchooser — Color choosing dialog12597893
Ref: library/tkinter colorchooser doc12598102
Ref: 3fdf12598102
Ref: library/tkinter colorchooser module-tkinter colorchooser12598102
Ref: f112598102
Ref: library/tkinter colorchooser tkinter-colorchooser-color-choosing-dialog12598102
Ref: 3fe012598102
Ref: library/tkinter colorchooser translation-repo12598102
Ref: 3fe112598102
Ref: library/tkinter colorchooser tkinter colorchooser Chooser12598596
Ref: 3fe212598596
Ref: library/tkinter colorchooser tkinter colorchooser askcolor12598662
Ref: 3fe412598662
Ref: tkinter colorchooser — Color choosing dialog-Footnote-112599056
Node: tkinter font — Tkinter font wrapper12599137
Ref: library/tkinter font doc12599323
Ref: 3fe512599323
Ref: library/tkinter font module-tkinter font12599323
Ref: f512599323
Ref: library/tkinter font tkinter-font-tkinter-font-wrapper12599323
Ref: 3fe612599323
Ref: library/tkinter font translation-repo12599323
Ref: 3fe712599323
Ref: library/tkinter font tkinter font NORMAL12599675
Ref: 3fe812599675
Ref: library/tkinter font tkinter font BOLD12599705
Ref: 3fe912599705
Ref: library/tkinter font tkinter font ITALIC12599733
Ref: 3fea12599733
Ref: library/tkinter font tkinter font ROMAN12599763
Ref: 3feb12599763
Ref: library/tkinter font tkinter font Font12599793
Ref: 1a7412599793
Ref: library/tkinter font tkinter font Font actual12601092
Ref: 3fec12601092
Ref: library/tkinter font tkinter font Font cget12601193
Ref: 3fed12601193
Ref: library/tkinter font tkinter font Font config12601271
Ref: 3fee12601271
Ref: library/tkinter font tkinter font Font copy12601350
Ref: 3fef12601350
Ref: library/tkinter font tkinter font Font measure12601428
Ref: 3ff012601428
Ref: library/tkinter font tkinter font Font metrics12601687
Ref: 3ff112601687
Ref: library/tkinter font tkinter font families12602264
Ref: 3ff212602264
Ref: library/tkinter font tkinter font names12602371
Ref: 3ff312602371
Ref: library/tkinter font tkinter font nametofont12602458
Ref: 1a7612602458
Ref: tkinter font — Tkinter font wrapper-Footnote-112602682
Node: Tkinter Dialogs12602754
Ref: library/dialog doc12602940
Ref: 3ff412602940
Ref: library/dialog tkinter-dialogs12602940
Ref: 3ff512602940
Ref: library/dialog translation-repo12602940
Ref: 3ff612602940
Node: tkinter simpledialog — Standard Tkinter input dialogs12603311
Ref: library/dialog module-tkinter simpledialog12603472
Ref: f812603472
Ref: library/dialog tkinter-simpledialog-standard-tkinter-input-dialogs12603472
Ref: 3ff712603472
Ref: library/dialog tkinter simpledialog askfloat12603870
Ref: 3ff812603870
Ref: library/dialog tkinter simpledialog askinteger12603936
Ref: 1a7712603936
Ref: library/dialog tkinter simpledialog askstring12604004
Ref: 3ff912604004
Ref: library/dialog tkinter simpledialog Dialog12604184
Ref: 3ffa12604184
Ref: library/dialog tkinter simpledialog Dialog body12604286
Ref: 3ffb12604286
Ref: library/dialog tkinter simpledialog Dialog buttonbox12604440
Ref: 3ffc12604440
Ref: tkinter simpledialog — Standard Tkinter input dialogs-Footnote-112604611
Node: tkinter filedialog — File selection dialogs12604692
Ref: library/dialog module-tkinter filedialog12604910
Ref: f412604910
Ref: library/dialog tkinter-filedialog-file-selection-dialogs12604910
Ref: 3ffd12604910
Ref: tkinter filedialog — File selection dialogs-Footnote-112605338
Node: Native Load/Save Dialogs12605417
Ref: library/dialog native-load-save-dialogs12605523
Ref: 3ffe12605523
Ref: library/dialog tkinter filedialog askopenfile12606532
Ref: 3fff12606532
Ref: library/dialog tkinter filedialog askopenfiles12606599
Ref: 400012606599
Ref: library/dialog tkinter filedialog asksaveasfile12606794
Ref: 400212606794
Ref: library/dialog tkinter filedialog askopenfilename12606963
Ref: 400412606963
Ref: library/dialog tkinter filedialog askopenfilenames12607024
Ref: 400512607024
Ref: library/dialog tkinter filedialog asksaveasfilename12607235
Ref: 400612607235
Ref: library/dialog tkinter filedialog askdirectory12607380
Ref: 400712607380
Ref: library/dialog tkinter filedialog Open12607606
Ref: 400112607606
Ref: library/dialog tkinter filedialog SaveAs12607666
Ref: 400312607666
Ref: library/dialog tkinter filedialog Directory12607987
Ref: 400812607987
Ref: library/dialog tkinter filedialog FileDialog12608219
Ref: 400912608219
Ref: library/dialog tkinter filedialog FileDialog cancel_command12608326
Ref: 400a12608326
Ref: library/dialog tkinter filedialog FileDialog dirs_double_event12608429
Ref: 400b12608429
Ref: library/dialog tkinter filedialog FileDialog dirs_select_event12608535
Ref: 400c12608535
Ref: library/dialog tkinter filedialog FileDialog files_double_event12608634
Ref: 400d12608634
Ref: library/dialog tkinter filedialog FileDialog files_select_event12608736
Ref: 400e12608736
Ref: library/dialog tkinter filedialog FileDialog filter_command12608838
Ref: 400f12608838
Ref: library/dialog tkinter filedialog FileDialog get_filter12608926
Ref: 401012608926
Ref: library/dialog tkinter filedialog FileDialog get_selection12609012
Ref: 401112609012
Ref: library/dialog tkinter filedialog FileDialog go12609096
Ref: 401212609096
Ref: library/dialog tkinter filedialog FileDialog ok_event12609238
Ref: 401312609238
Ref: library/dialog tkinter filedialog FileDialog quit12609325
Ref: 401412609325
Ref: library/dialog tkinter filedialog FileDialog set_filter12609410
Ref: 401512609410
Ref: library/dialog tkinter filedialog FileDialog set_selection12609482
Ref: 401612609482
Ref: library/dialog tkinter filedialog LoadFileDialog12609577
Ref: 401712609577
Ref: library/dialog tkinter filedialog LoadFileDialog ok_command12609741
Ref: 401812609741
Ref: library/dialog tkinter filedialog SaveFileDialog12609882
Ref: 401912609882
Ref: library/dialog tkinter filedialog SaveFileDialog ok_command12610048
Ref: 401a12610048
Node: tkinter commondialog — Dialog window templates12610260
Ref: library/dialog module-tkinter commondialog12610414
Ref: f212610414
Ref: library/dialog tkinter-commondialog-dialog-window-templates12610414
Ref: 401b12610414
Ref: library/dialog tkinter commondialog Dialog12610802
Ref: 3fe312610802
Ref: library/dialog tkinter commondialog Dialog show12610867
Ref: 401c12610867
Ref: tkinter commondialog — Dialog window templates-Footnote-112611072
Node: tkinter messagebox — Tkinter message prompts12611153
Ref: library/tkinter messagebox doc12611347
Ref: 401d12611347
Ref: library/tkinter messagebox module-tkinter messagebox12611347
Ref: f612611347
Ref: library/tkinter messagebox tkinter-messagebox-tkinter-message-prompts12611347
Ref: 401e12611347
Ref: library/tkinter messagebox translation-repo12611347
Ref: 401f12611347
Ref: library/tkinter messagebox tkinter messagebox Message12612042
Ref: 402412612042
Ref: library/tkinter messagebox tkinter messagebox Message show12614183
Ref: 402912614183
Ref: library/tkinter messagebox tkinter messagebox showinfo12614488
Ref: 402a12614488
Ref: library/tkinter messagebox tkinter messagebox showwarning12614701
Ref: 402b12614701
Ref: library/tkinter messagebox tkinter messagebox showerror12614887
Ref: 402c12614887
Ref: library/tkinter messagebox tkinter messagebox askquestion12615096
Ref: 402d12615096
Ref: library/tkinter messagebox tkinter messagebox askokcancel12615346
Ref: 402e12615346
Ref: library/tkinter messagebox tkinter messagebox askretrycancel12615611
Ref: 402f12615611
Ref: library/tkinter messagebox tkinter messagebox askyesno12615885
Ref: 403112615885
Ref: library/tkinter messagebox tkinter messagebox askyesnocancel12616122
Ref: 403212616122
Ref: library/tkinter messagebox messagebox-buttons12616415
Ref: 402512616415
Ref: library/tkinter messagebox tkinter messagebox ABORT12616443
Ref: 403312616443
Ref: library/tkinter messagebox tkinter messagebox RETRY12616489
Ref: 403012616489
Ref: library/tkinter messagebox tkinter messagebox IGNORE12616535
Ref: 403412616535
Ref: library/tkinter messagebox tkinter messagebox OK12616583
Ref: 402012616583
Ref: library/tkinter messagebox tkinter messagebox CANCEL12616623
Ref: 402112616623
Ref: library/tkinter messagebox tkinter messagebox YES12616671
Ref: 402212616671
Ref: library/tkinter messagebox tkinter messagebox NO12616713
Ref: 402312616713
Ref: library/tkinter messagebox messagebox-types12616752
Ref: 402812616752
Ref: library/tkinter messagebox tkinter messagebox ABORTRETRYIGNORE12616781
Ref: 403512616781
Ref: library/tkinter messagebox tkinter messagebox OKCANCEL12617069
Ref: 403612617069
Ref: library/tkinter messagebox tkinter messagebox RETRYCANCEL12617218
Ref: 403712617218
Ref: library/tkinter messagebox tkinter messagebox YESNO12617376
Ref: 403812617376
Ref: library/tkinter messagebox tkinter messagebox YESNOCANCEL12617516
Ref: 403912617516
Ref: library/tkinter messagebox messagebox-icons12617689
Ref: 402612617689
Ref: library/tkinter messagebox tkinter messagebox ERROR12617703
Ref: 403a12617703
Ref: library/tkinter messagebox tkinter messagebox INFO12617749
Ref: 402712617749
Ref: library/tkinter messagebox tkinter messagebox QUESTION12617793
Ref: 403b12617793
Ref: library/tkinter messagebox tkinter messagebox WARNING12617845
Ref: 403c12617845
Ref: tkinter messagebox — Tkinter message prompts-Footnote-112617931
Node: tkinter scrolledtext — Scrolled Text Widget12618010
Ref: library/tkinter scrolledtext doc12618226
Ref: 403d12618226
Ref: library/tkinter scrolledtext module-tkinter scrolledtext12618226
Ref: f712618226
Ref: library/tkinter scrolledtext tkinter-scrolledtext-scrolled-text-widget12618226
Ref: 403e12618226
Ref: library/tkinter scrolledtext translation-repo12618226
Ref: 403f12618226
Ref: library/tkinter scrolledtext tkinter scrolledtext ScrolledText12619134
Ref: 404012619134
Ref: library/tkinter scrolledtext tkinter scrolledtext ScrolledText frame12619200
Ref: 404112619200
Ref: library/tkinter scrolledtext tkinter scrolledtext ScrolledText vbar12619297
Ref: 404212619297
Ref: tkinter scrolledtext — Scrolled Text Widget-Footnote-112619393
Node: tkinter dnd — Drag and drop support12619474
Ref: library/tkinter dnd doc12619677
Ref: 404312619677
Ref: library/tkinter dnd module-tkinter dnd12619677
Ref: f312619677
Ref: library/tkinter dnd tkinter-dnd-drag-and-drop-support12619677
Ref: 404412619677
Ref: library/tkinter dnd translation-repo12619677
Ref: 404512619677
Ref: library/tkinter dnd tkinter dnd DndHandler12621174
Ref: 404712621174
Ref: library/tkinter dnd tkinter dnd DndHandler cancel12621362
Ref: 404812621362
Ref: library/tkinter dnd tkinter dnd DndHandler finish12621445
Ref: 404912621445
Ref: library/tkinter dnd tkinter dnd DndHandler on_motion12621539
Ref: 404a12621539
Ref: library/tkinter dnd tkinter dnd DndHandler on_release12621665
Ref: 404b12621665
Ref: library/tkinter dnd tkinter dnd dnd_start12621771
Ref: 404612621771
Ref: tkinter dnd — Drag and drop support-Footnote-112621963
Node: tkinter ttk — Tk themed widgets12622034
Ref: library/tkinter ttk doc12622227
Ref: 404c12622227
Ref: library/tkinter ttk module-tkinter ttk12622227
Ref: f912622227
Ref: library/tkinter ttk tkinter-ttk-tk-themed-widgets12622227
Ref: 404d12622227
Ref: library/tkinter ttk translation-repo12622227
Ref: 404e12622227
Ref: tkinter ttk — Tk themed widgets-Footnote-112623136
Ref: tkinter ttk — Tk themed widgets-Footnote-212623207
Node: Using Ttk12623260
Ref: library/tkinter ttk using-ttk12623359
Ref: 404f12623359
Ref: Using Ttk-Footnote-112624510
Node: Ttk Widgets12624574
Ref: library/tkinter ttk ttk-widgets12624688
Ref: 405012624688
Node: Widget12625796
Ref: library/tkinter ttk widget12625909
Ref: 405612625909
Node: Standard Options12626226
Ref: library/tkinter ttk standard-options12626319
Ref: 405712626319
Node: Scrollable Widget Options12627860
Ref: library/tkinter ttk scrollable-widget-options12627975
Ref: 405812627975
Node: Label Options12629008
Ref: library/tkinter ttk label-options12629128
Ref: 405912629128
Node: Compatibility Options12631462
Ref: library/tkinter ttk compatibility-options12631570
Ref: 405a12631570
Node: Widget States12632061
Ref: library/tkinter ttk widget-states12632166
Ref: 405c12632166
Node: ttk Widget12633670
Ref: library/tkinter ttk ttk-widget12633745
Ref: 405d12633745
Ref: library/tkinter ttk tkinter ttk Widget12633932
Ref: 405412633932
Ref: library/tkinter ttk tkinter ttk Widget identify12633963
Ref: 405e12633963
Ref: library/tkinter ttk tkinter ttk Widget instate12634206
Ref: 405f12634206
Ref: library/tkinter ttk tkinter ttk Widget state12634550
Ref: 405b12634550
Node: Combobox12634938
Ref: library/tkinter ttk combobox12635047
Ref: 406012635047
Node: Options12635742
Ref: library/tkinter ttk options12635817
Ref: 406112635817
Node: Virtual events12638108
Ref: library/tkinter ttk virtual-events12638204
Ref: 406212638204
Node: ttk Combobox12638384
Ref: library/tkinter ttk ttk-combobox12638464
Ref: 406312638464
Ref: library/tkinter ttk tkinter ttk Combobox12638511
Ref: 405112638511
Ref: library/tkinter ttk tkinter ttk Combobox current12638544
Ref: 406412638544
Ref: library/tkinter ttk tkinter ttk Combobox get12638820
Ref: 406512638820
Ref: library/tkinter ttk tkinter ttk Combobox set12638899
Ref: 406612638899
Node: Spinbox12638983
Ref: library/tkinter ttk spinbox12639094
Ref: 406712639094
Node: Options<2>12639854
Ref: library/tkinter ttk id112639934
Ref: 406812639934
Node: Virtual events<2>12642320
Ref: library/tkinter ttk id212642420
Ref: 406912642420
Node: ttk Spinbox12642628
Ref: library/tkinter ttk ttk-spinbox12642709
Ref: 406a12642709
Ref: library/tkinter ttk tkinter ttk Spinbox12642754
Ref: bb212642754
Ref: library/tkinter ttk tkinter ttk Spinbox get12642786
Ref: 406b12642786
Ref: library/tkinter ttk tkinter ttk Spinbox set12642864
Ref: 406c12642864
Node: Notebook12642947
Ref: library/tkinter ttk notebook12643061
Ref: 406d12643061
Node: Options<3>12643421
Ref: library/tkinter ttk id312643496
Ref: 406e12643496
Node: Tab Options12644571
Ref: library/tkinter ttk tab-options12644670
Ref: 406f12644670
Node: Tab Identifiers12646555
Ref: library/tkinter ttk tab-identifiers12646658
Ref: 407112646658
Node: Virtual Events12647192
Ref: library/tkinter ttk id412647296
Ref: 407312647296
Node: ttk Notebook12647440
Ref: library/tkinter ttk ttk-notebook12647520
Ref: 407412647520
Ref: library/tkinter ttk tkinter ttk Notebook12647567
Ref: 405212647567
Ref: library/tkinter ttk tkinter ttk Notebook add12647600
Ref: 407512647600
Ref: library/tkinter ttk tkinter ttk Notebook forget12647885
Ref: 407612647885
Ref: library/tkinter ttk tkinter ttk Notebook hide12648023
Ref: 407712648023
Ref: library/tkinter ttk tkinter ttk Notebook identify12648333
Ref: 407812648333
Ref: library/tkinter ttk tkinter ttk Notebook index12648475
Ref: 407212648475
Ref: library/tkinter ttk tkinter ttk Notebook insert12648654
Ref: 407912648654
Ref: library/tkinter ttk tkinter ttk Notebook select12649039
Ref: 407a12649039
Ref: library/tkinter ttk tkinter ttk Notebook tab12649353
Ref: 407b12649353
Ref: library/tkinter ttk tkinter ttk Notebook tabs12649699
Ref: 407c12649699
Ref: library/tkinter ttk tkinter ttk Notebook enable_traversal12649787
Ref: 407012649787
Node: Progressbar12650638
Ref: library/tkinter ttk progressbar12650754
Ref: 407d12650754
Node: Options<4>12651195
Ref: library/tkinter ttk id512651277
Ref: 407e12651277
Node: ttk Progressbar12652977
Ref: library/tkinter ttk ttk-progressbar12653059
Ref: 407f12653059
Ref: library/tkinter ttk tkinter ttk Progressbar12653112
Ref: 405312653112
Ref: library/tkinter ttk tkinter ttk Progressbar start12653148
Ref: 408012653148
Ref: library/tkinter ttk tkinter ttk Progressbar step12653416
Ref: 408112653416
Ref: library/tkinter ttk tkinter ttk Progressbar stop12653563
Ref: 408212653563
Node: Separator12653748
Ref: library/tkinter ttk separator12653864
Ref: 408312653864
Node: Options<5>12654094
Ref: library/tkinter ttk id612654150
Ref: 408412654150
Node: Sizegrip12654504
Ref: library/tkinter ttk sizegrip12654617
Ref: 408512654617
Node: Platform-specific notes12654967
Ref: library/tkinter ttk platform-specific-notes12655048
Ref: 408612655048
Node: Bugs12655304
Ref: library/tkinter ttk bugs12655385
Ref: 408712655385
Node: Treeview12655658
Ref: library/tkinter ttk treeview12655773
Ref: 408812655773
Node: Options<6>12657131
Ref: library/tkinter ttk id712657207
Ref: 408c12657207
Node: Item Options12659623
Ref: library/tkinter ttk item-options12659719
Ref: 408d12659719
Node: Tag Options12660775
Ref: library/tkinter ttk tag-options12660879
Ref: 408e12660879
Node: Column Identifiers12661529
Ref: library/tkinter ttk column-identifiers12661638
Ref: 408912661638
Node: Virtual Events<2>12662510
Ref: library/tkinter ttk id812662620
Ref: 408f12662620
Node: ttk Treeview12663452
Ref: library/tkinter ttk ttk-treeview12663535
Ref: 409112663535
Ref: library/tkinter ttk tkinter ttk Treeview12663582
Ref: aa512663582
Ref: library/tkinter ttk tkinter ttk Treeview bbox12663615
Ref: 409212663615
Ref: library/tkinter ttk tkinter ttk Treeview get_children12664052
Ref: 409312664052
Ref: library/tkinter ttk tkinter ttk Treeview set_children12664218
Ref: 409412664218
Ref: library/tkinter ttk tkinter ttk Treeview column12664610
Ref: 409512664610
Ref: library/tkinter ttk tkinter ttk Treeview delete12665855
Ref: 409612665855
Ref: library/tkinter ttk tkinter ttk Treeview detach12666001
Ref: 409712666001
Ref: library/tkinter ttk tkinter ttk Treeview exists12666312
Ref: 409812666312
Ref: library/tkinter ttk tkinter ttk Treeview focus12666422
Ref: 409012666422
Ref: library/tkinter ttk tkinter ttk Treeview heading12666615
Ref: 409912666615
Ref: library/tkinter ttk tkinter ttk Treeview identify12667606
Ref: 409a12667606
Ref: library/tkinter ttk tkinter ttk Treeview identify_row12667843
Ref: 409b12667843
Ref: library/tkinter ttk tkinter ttk Treeview identify_column12667938
Ref: 409c12667938
Ref: library/tkinter ttk tkinter ttk Treeview identify_region12668099
Ref: 409d12668099
Ref: library/tkinter ttk tkinter ttk Treeview identify_element12668735
Ref: 409e12668735
Ref: library/tkinter ttk tkinter ttk Treeview index12668863
Ref: 409f12668863
Ref: library/tkinter ttk tkinter ttk Treeview insert12668991
Ref: 40a012668991
Ref: library/tkinter ttk tkinter ttk Treeview item12669889
Ref: 40a112669889
Ref: library/tkinter ttk tkinter ttk Treeview move12670267
Ref: 40a212670267
Ref: library/tkinter ttk tkinter ttk Treeview next12670705
Ref: 40a312670705
Ref: library/tkinter ttk tkinter ttk Treeview parent12670860
Ref: 40a412670860
Ref: library/tkinter ttk tkinter ttk Treeview prev12671011
Ref: 40a512671011
Ref: library/tkinter ttk tkinter ttk Treeview reattach12671171
Ref: 40a612671171
Ref: library/tkinter ttk tkinter ttk Treeview see12671273
Ref: 40a712671273
Ref: library/tkinter ttk tkinter ttk Treeview selection12671529
Ref: aa412671529
Ref: library/tkinter ttk tkinter ttk Treeview selection_set12671777
Ref: aa612671777
Ref: library/tkinter ttk tkinter ttk Treeview selection_add12671982
Ref: 40a812671982
Ref: library/tkinter ttk tkinter ttk Treeview selection_remove12672182
Ref: 40a912672182
Ref: library/tkinter ttk tkinter ttk Treeview selection_toggle12672390
Ref: 40aa12672390
Ref: library/tkinter ttk tkinter ttk Treeview set12672615
Ref: 40ab12672615
Ref: library/tkinter ttk tkinter ttk Treeview tag_bind12672980
Ref: 40ac12672980
Ref: library/tkinter ttk tkinter ttk Treeview tag_configure12673250
Ref: 40ad12673250
Ref: library/tkinter ttk tkinter ttk Treeview tag_has12673679
Ref: 40ae12673679
Ref: library/tkinter ttk tkinter ttk Treeview xview12673964
Ref: 408a12673964
Ref: library/tkinter ttk tkinter ttk Treeview yview12674060
Ref: 408b12674060
Node: Ttk Styling12674154
Ref: library/tkinter ttk ttk-styling12674252
Ref: 40af12674252
Ref: library/tkinter ttk ttkstyling12674252
Ref: 405512674252
Ref: library/tkinter ttk tkinter ttk Style12674844
Ref: 25912674844
Ref: library/tkinter ttk tkinter ttk Style configure12674933
Ref: 40b012674933
Ref: library/tkinter ttk tkinter ttk Style map12675660
Ref: 1a8d12675660
Ref: library/tkinter ttk tkinter ttk Style lookup12676925
Ref: 40b112676925
Ref: library/tkinter ttk tkinter ttk Style layout12677446
Ref: 40b212677446
Ref: library/tkinter ttk tkinter ttk Style element_create12678758
Ref: 25812678758
Ref: library/tkinter ttk tkinter ttk Style element_names12684119
Ref: 40b412684119
Ref: library/tkinter ttk tkinter ttk Style element_options12684224
Ref: 40b512684224
Ref: library/tkinter ttk tkinter ttk Style theme_create12684330
Ref: 40b612684330
Ref: library/tkinter ttk tkinter ttk Style theme_settings12684743
Ref: 40b712684743
Ref: library/tkinter ttk tkinter ttk Style theme_names12686219
Ref: 40b812686219
Ref: library/tkinter ttk tkinter ttk Style theme_use12686299
Ref: 40b912686299
Ref: Ttk Styling-Footnote-112686596
Node: Layouts12686658
Ref: library/tkinter ttk layouts12686713
Ref: 40b312686713
Ref: library/tkinter ttk layout12687785
Ref: 40ba12687785
Node: IDLE — Python editor and shell<2>12687786
Ref: library/idle doc12687968
Ref: 40bb12687968
Ref: library/idle idle12687968
Ref: 105012687968
Ref: library/idle idle-python-editor-and-shell12687968
Ref: 40bc12687968
Ref: library/idle translation-repo12687968
Ref: 40bd12687968
Ref: IDLE — Python editor and shell<2>-Footnote-112689325
Node: Menus12689390
Ref: library/idle menus12689498
Ref: 40be12689498
Node: File menu Shell and Editor12690780
Ref: library/idle file-menu-shell-and-editor12690883
Ref: 40bf12690883
Node: Edit menu Shell and Editor12692733
Ref: library/idle edit-menu-shell-and-editor12692875
Ref: 40c012692875
Node: Format menu Editor window only12694616
Ref: library/idle format-menu12694759
Ref: 40c312694759
Ref: library/idle format-menu-editor-window-only12694759
Ref: 40c412694759
Node: Run menu Editor window only12696082
Ref: library/idle run-menu-editor-window-only12696227
Ref: 40c612696227
Ref: library/idle run-module12696306
Ref: 40c712696306
Ref: library/idle run-custom12696798
Ref: 40c912696798
Ref: library/idle check-module12697058
Ref: 40c812697058
Ref: library/idle python-shell12697402
Ref: 40ca12697402
Node: Shell menu Shell window only12697464
Ref: library/idle shell-menu-shell-window-only12697607
Ref: 40cb12697607
Node: Debug menu Shell window only12698124
Ref: library/idle debug-menu-shell-window-only12698269
Ref: 40cc12698269
Node: Options menu Shell and Editor12699225
Ref: library/idle options-menu-shell-and-editor12699370
Ref: 40cd12699370
Node: Window menu Shell and Editor12700987
Ref: library/idle window-menu-shell-and-editor12701130
Ref: 40d012701130
Node: Help menu Shell and Editor12701322
Ref: library/idle help-menu-shell-and-editor12701449
Ref: 40d112701449
Node: Context menus12702169
Ref: library/idle context-menus12702259
Ref: 40d312702259
Node: Editing and Navigation12703433
Ref: library/idle editing-and-navigation12703576
Ref: 40d412703576
Ref: library/idle id112703576
Ref: 40d512703576
Node: Editor windows12703834
Ref: library/idle editor-windows12703928
Ref: 40d612703928
Node: Key bindings12704550
Ref: library/idle key-bindings12704674
Ref: 40d712704674
Node: Automatic indentation12706093
Ref: library/idle automatic-indentation12706221
Ref: 40d812706221
Node: Search and Replace12706801
Ref: library/idle search-and-replace12706928
Ref: 40d912706928
Node: Completions12707262
Ref: library/idle completions12707376
Ref: 40c112707376
Ref: library/idle id212707376
Ref: 40da12707376
Node: Calltips12710026
Ref: library/idle calltips12710134
Ref: 40c212710134
Ref: library/idle id312710134
Ref: 40db12710134
Node: Format block12711760
Ref: library/idle format-block12711869
Ref: 40c512711869
Ref: library/idle id412711869
Ref: 40dc12711869
Node: Code Context12712392
Ref: library/idle code-context12712505
Ref: 40cf12712505
Ref: library/idle id512712505
Ref: 40dd12712505
Node: Shell window12713393
Ref: library/idle shell-window12713505
Ref: 40de12713505
Node: Text colors12715184
Ref: library/idle text-colors12715275
Ref: 40df12715275
Node: Startup and Code Execution12716304
Ref: library/idle startup-and-code-execution12716462
Ref: 40e012716462
Node: Command-line usage<3>12717616
Ref: library/idle command-line-usage12717724
Ref: 40e112717724
Ref: library/idle idlelib-cli12717724
Ref: 40e212717724
Ref: library/idle cmdoption-idle-c12717955
Ref: 40e312717955
Ref: library/idle cmdoption-idle-d12718167
Ref: 40e412718167
Ref: library/idle cmdoption-idle-e12718236
Ref: 40e512718236
Ref: library/idle cmdoption-idle-h12718281
Ref: 40e612718281
Ref: library/idle cmdoption-idle-i12718369
Ref: 40e712718369
Ref: library/idle cmdoption-idle-r12718412
Ref: 40e812718412
Ref: library/idle cmdoption-idle-s12718485
Ref: 40e912718485
Ref: library/idle cmdoption-idle-t12718661
Ref: 40ea12718661
Ref: library/idle cmdoption-idle-012718726
Ref: 40eb12718726
Node: Startup failure12719313
Ref: library/idle startup-failure12719447
Ref: 40ec12719447
Node: Running user code12722634
Ref: library/idle running-user-code12722767
Ref: 40ed12722767
Node: User output in Shell12725551
Ref: library/idle user-output-in-shell12725700
Ref: 40ee12725700
Node: Developing tkinter applications12728786
Ref: library/idle developing-tkinter-applications12728946
Ref: 40ef12728946
Node: Running without a subprocess12730195
Ref: library/idle running-without-a-subprocess12730326
Ref: 40f012730326
Node: Help and Preferences12731708
Ref: library/idle help-and-preferences12731890
Ref: 40f112731890
Node: Help sources12732037
Ref: library/idle help-sources12732134
Ref: 40d212732134
Ref: library/idle id612732134
Ref: 40f212732134
Node: Setting preferences12733004
Ref: library/idle preferences12733123
Ref: 40ce12733123
Ref: library/idle setting-preferences12733123
Ref: 40f312733123
Node: IDLE on macOS12734132
Ref: library/idle idle-on-macos12734249
Ref: 40f412734249
Node: Extensions12734516
Ref: library/idle extensions12734605
Ref: 40f512734605
Node: idlelib — implementation of IDLE application12734956
Ref: library/idle idlelib-implementation-of-idle-application12735103
Ref: 40f612735103
Ref: library/idle module-idlelib12735103
Ref: 7312735103
Ref: idlelib — implementation of IDLE application-Footnote-112735811
Ref: idlelib — implementation of IDLE application-Footnote-212735875
Node: turtle — Turtle graphics12735917
Ref: library/turtle doc12736057
Ref: 40f712736057
Ref: library/turtle module-turtle12736057
Ref: 10112736057
Ref: library/turtle translation-repo12736057
Ref: 40f812736057
Ref: library/turtle turtle-turtle-graphics12736057
Ref: 40f912736057
Ref: turtle — Turtle graphics-Footnote-112736740
Node: Introduction<11>12736806
Ref: library/turtle introduction12736905
Ref: 40fa12736905
Ref: Introduction<11>-Footnote-112737161
Node: Get started12737214
Ref: library/turtle get-started12737333
Ref: 40fb12737333
Node: Tutorial<4>12738521
Ref: library/turtle turtle-tutorial12738633
Ref: 40fc12738633
Ref: library/turtle tutorial12738633
Ref: 40fd12738633
Node: Starting a turtle environment12738868
Ref: library/turtle starting-a-turtle-environment12738967
Ref: 40fe12738967
Node: Basic drawing12739282
Ref: library/turtle basic-drawing12739417
Ref: 40ff12739417
Node: Pen control12740058
Ref: library/turtle pen-control12740151
Ref: 410012740151
Node: The turtle’s position12740481
Ref: library/turtle the-turtle-s-position12740574
Ref: 410112740574
Node: Making algorithmic patterns12741019
Ref: library/turtle making-algorithmic-patterns12741116
Ref: 410212741116
Node: How to…12742095
Ref: library/turtle how-to12742221
Ref: 410312742221
Ref: library/turtle turtle-how-to12742221
Ref: 410412742221
Node: Get started as quickly as possible12742488
Ref: library/turtle get-started-as-quickly-as-possible12742608
Ref: 410512742608
Ref: library/turtle note12743366
Ref: 410612743366
Node: Use the turtle module namespace12743638
Ref: library/turtle use-the-turtle-module-namespace12743798
Ref: 410712743798
Node: Use turtle graphics in a script12744468
Ref: library/turtle use-turtle-graphics-in-a-script12744629
Ref: 410812744629
Node: Use object-oriented turtle graphics12745325
Ref: library/turtle use-object-oriented-turtle-graphics12745446
Ref: 410912745446
Node: Turtle graphics reference12746678
Ref: library/turtle turtle-graphics-reference12746848
Ref: 410c12746848
Node: Turtle methods12747168
Ref: library/turtle turtle-methods12747283
Ref: 410d12747283
Node: Methods of TurtleScreen/Screen12750299
Ref: library/turtle methods-of-turtlescreen-screen12750414
Ref: 415a12750414
Node: Methods of RawTurtle/Turtle and corresponding functions12751738
Ref: library/turtle methods-of-rawturtle-turtle-and-corresponding-functions12751957
Ref: 417912751957
Node: Turtle motion12752373
Ref: library/turtle turtle-motion12752508
Ref: 417a12752508
Ref: library/turtle turtle forward12752559
Ref: 330912752559
Ref: library/turtle turtle fd12752599
Ref: 410e12752599
Ref: library/turtle turtle back12753037
Ref: 411112753037
Ref: library/turtle turtle bk12753074
Ref: 411012753074
Ref: library/turtle turtle backward12753109
Ref: 410f12753109
Ref: library/turtle turtle right12753481
Ref: 411212753481
Ref: library/turtle turtle rt12753516
Ref: 411312753516
Ref: library/turtle turtle left12753982
Ref: 411412753982
Ref: library/turtle turtle lt12754016
Ref: 411512754016
Ref: library/turtle turtle goto12754479
Ref: 411612754479
Ref: library/turtle turtle setpos12754517
Ref: 411712754517
Ref: library/turtle turtle setposition12754557
Ref: 411812754557
Ref: library/turtle turtle teleport12755312
Ref: 183812755312
Ref: library/turtle turtle setx12756324
Ref: 411912756324
Ref: library/turtle turtle sety12756648
Ref: 411a12756648
Ref: library/turtle turtle setheading12756971
Ref: 411b12756971
Ref: library/turtle turtle seth12757014
Ref: 411c12757014
Ref: library/turtle turtle home12757830
Ref: 411d12757830
Ref: library/turtle turtle circle12758257
Ref: 411e12758257
Ref: library/turtle turtle dot12759642
Ref: 411f12759642
Ref: library/turtle turtle stamp12760345
Ref: 412012760345
Ref: library/turtle turtle clearstamp12760682
Ref: 412112760682
Ref: library/turtle turtle clearstamps12761192
Ref: 412212761192
Ref: library/turtle turtle undo12761703
Ref: 412312761703
Ref: library/turtle turtle speed12762028
Ref: 412412762028
Node: Tell Turtle’s state12763027
Ref: library/turtle tell-turtle-s-state12763195
Ref: 417c12763195
Ref: library/turtle turtle position12763260
Ref: 412512763260
Ref: library/turtle turtle pos12763293
Ref: 412612763293
Ref: library/turtle turtle towards12763465
Ref: 412712763465
Ref: library/turtle turtle xcor12764030
Ref: 412812764030
Ref: library/turtle turtle ycor12764310
Ref: 412912764310
Ref: library/turtle turtle heading12764597
Ref: 412a12764597
Ref: library/turtle turtle distance12764845
Ref: 412b12764845
Node: Settings for measurement12765434
Ref: library/turtle settings-for-measurement12765603
Ref: 417d12765603
Ref: library/turtle turtle degrees12765676
Ref: 412c12765676
Ref: library/turtle turtle radians12766316
Ref: 412d12766316
Node: Pen control<2>12766641
Ref: library/turtle id112766801
Ref: 417e12766801
Node: Drawing state12766931
Ref: library/turtle drawing-state12767017
Ref: 417f12767017
Ref: library/turtle turtle pendown12767068
Ref: 412e12767068
Ref: library/turtle turtle pd12767100
Ref: 412f12767100
Ref: library/turtle turtle down12767127
Ref: 413012767127
Ref: library/turtle turtle penup12767206
Ref: 413112767206
Ref: library/turtle turtle pu12767236
Ref: 413212767236
Ref: library/turtle turtle up12767263
Ref: 413312767263
Ref: library/turtle turtle pensize12767341
Ref: 413412767341
Ref: library/turtle turtle width12767383
Ref: 413512767383
Ref: library/turtle turtle pen12767845
Ref: 413612767845
Ref: library/turtle turtle isdown12769749
Ref: 413712769749
Node: Color control12769999
Ref: library/turtle color-control12770101
Ref: 418012770101
Ref: library/turtle turtle pencolor12770152
Ref: 413912770152
Ref: library/turtle turtle fillcolor12771845
Ref: 413a12771845
Ref: library/turtle turtle color12773444
Ref: 413812773444
Node: Filling12774770
Ref: library/turtle filling12774879
Ref: 418112774879
Ref: library/turtle turtle filling12774918
Ref: 413b12774918
Ref: library/turtle turtle begin_fill12775177
Ref: 413c12775177
Ref: library/turtle turtle end_fill12775274
Ref: 413d12775274
Node: More drawing control12775821
Ref: library/turtle more-drawing-control12775908
Ref: 418212775908
Ref: library/turtle turtle reset12775973
Ref: 413e12775973
Ref: library/turtle turtle clear12776421
Ref: 413f12776421
Ref: library/turtle turtle write12776625
Ref: 414012776625
Node: Turtle state12777404
Ref: library/turtle turtle-state12777552
Ref: 418312777552
Node: Visibility12777641
Ref: library/turtle visibility12777719
Ref: 418412777719
Ref: library/turtle turtle hideturtle12777764
Ref: 414312777764
Ref: library/turtle turtle ht12777799
Ref: 414412777799
Ref: library/turtle turtle showturtle12778056
Ref: 414112778056
Ref: library/turtle turtle st12778091
Ref: 414212778091
Ref: library/turtle turtle isvisible12778185
Ref: 414512778185
Node: Appearance12778464
Ref: library/turtle appearance12778542
Ref: 418512778542
Ref: library/turtle turtle shape12778587
Ref: 414612778587
Ref: library/turtle turtle resizemode12779260
Ref: 414712779260
Ref: library/turtle turtle shapesize12780231
Ref: 414812780231
Ref: library/turtle turtle turtlesize12780323
Ref: 414912780323
Ref: library/turtle turtle shearfactor12781308
Ref: 414a12781308
Ref: library/turtle turtle tilt12781972
Ref: 414b12781972
Ref: library/turtle turtle tiltangle12782412
Ref: 72812782412
Ref: library/turtle turtle shapetransform12783134
Ref: 414c12783134
Ref: library/turtle turtle get_shapepoly12784166
Ref: 414d12784166
Node: Using events12784537
Ref: library/turtle using-events12784693
Ref: 418612784693
Ref: library/turtle turtle onrelease12785595
Ref: 414f12785595
Ref: library/turtle turtle ondrag12786606
Ref: 415012786606
Node: Special Turtle methods12787481
Ref: library/turtle special-turtle-methods12787640
Ref: 418712787640
Ref: library/turtle turtle begin_poly12787709
Ref: 415112787709
Ref: library/turtle turtle end_poly12787852
Ref: 415212787852
Ref: library/turtle turtle get_poly12788043
Ref: 415312788043
Ref: library/turtle turtle clone12788445
Ref: 415412788445
Ref: library/turtle turtle getturtle12788642
Ref: 415512788642
Ref: library/turtle turtle getpen12788676
Ref: 415612788676
Ref: library/turtle turtle getscreen12788944
Ref: 415712788944
Ref: library/turtle turtle setundobuffer12789250
Ref: 415812789250
Ref: library/turtle turtle undobufferentries12789687
Ref: 415912789687
Node: Compound shapes12789847
Ref: library/turtle compound-shapes12789985
Ref: 418912789985
Ref: library/turtle compoundshapes12789985
Ref: 418a12789985
Node: Methods of TurtleScreen/Screen and corresponding functions12791021
Ref: library/turtle methods-of-turtlescreen-screen-and-corresponding-functions12791229
Ref: 418d12791229
Node: Window control12791711
Ref: library/turtle window-control12791846
Ref: 418e12791846
Ref: library/turtle turtle bgcolor12791899
Ref: 415b12791899
Ref: library/turtle turtle bgpic12793223
Ref: 415c12793223
Ref: library/turtle turtle clearscreen12794099
Ref: 415d12794099
Ref: library/turtle turtle resetscreen12794608
Ref: 415e12794608
Ref: library/turtle turtle screensize12794707
Ref: 415f12794707
Ref: library/turtle turtle setworldcoordinates12795616
Ref: 416012795616
Node: Animation control12796598
Ref: library/turtle animation-control12796761
Ref: 418f12796761
Ref: library/turtle turtle delay12796820
Ref: 416112796820
Ref: library/turtle turtle tracer12797259
Ref: 416212797259
Ref: library/turtle turtle update12797960
Ref: 416312797960
Node: Using screen events12798132
Ref: library/turtle using-screen-events12798294
Ref: 419012798294
Ref: library/turtle turtle listen12798357
Ref: 416412798357
Ref: library/turtle turtle onkey12798585
Ref: 416512798585
Ref: library/turtle turtle onkeyrelease12798623
Ref: 416612798623
Ref: library/turtle turtle onkeypress12799245
Ref: 416712799245
Ref: library/turtle turtle onclick12799848
Ref: 414e12799848
Ref: library/turtle turtle onscreenclick12799900
Ref: 416812799900
Ref: library/turtle turtle ontimer12801088
Ref: 416912801088
Ref: library/turtle turtle mainloop12801572
Ref: 416a12801572
Ref: library/turtle turtle done12801605
Ref: 416b12801605
Node: Input methods12801931
Ref: library/turtle input-methods12802104
Ref: 419112802104
Ref: library/turtle turtle textinput12802155
Ref: 1a2112802155
Ref: library/turtle turtle numinput12802609
Ref: 1a2212802609
Node: Settings and special methods12803532
Ref: library/turtle settings-and-special-methods12803744
Ref: 419212803744
Ref: library/turtle turtle mode12803825
Ref: 416c12803825
Ref: library/turtle turtle colormode12805049
Ref: 416d12805049
Ref: library/turtle turtle getcanvas12805689
Ref: 416e12805689
Ref: library/turtle turtle getshapes12805940
Ref: 416f12805940
Ref: library/turtle turtle register_shape12806134
Ref: 417012806134
Ref: library/turtle turtle addshape12806189
Ref: 417112806189
Ref: library/turtle turtle turtles12807150
Ref: 417212807150
Ref: library/turtle turtle window_height12807316
Ref: 417312807316
Ref: library/turtle turtle window_width12807453
Ref: 417412807453
Node: Methods specific to Screen not inherited from TurtleScreen12807587
Ref: library/turtle methods-specific-to-screen-not-inherited-from-turtlescreen12807777
Ref: 419312807777
Ref: library/turtle screenspecific12807777
Ref: 419412807777
Ref: library/turtle turtle bye12807920
Ref: 417512807920
Ref: library/turtle turtle exitonclick12807987
Ref: 417612807987
Ref: library/turtle turtle setup12808427
Ref: 417712808427
Ref: library/turtle turtle title12809747
Ref: 417812809747
Node: Public classes12810013
Ref: library/turtle public-classes12810180
Ref: 419512810180
Ref: library/turtle turtle RawTurtle12810233
Ref: 419612810233
Ref: library/turtle turtle RawPen12810270
Ref: 419712810270
Ref: library/turtle turtle Turtle12810541
Ref: 419912810541
Ref: library/turtle turtle TurtleScreen12810733
Ref: 418812810733
Ref: library/turtle turtle Screen12810928
Ref: 410b12810928
Ref: library/turtle turtle ScrolledCanvas12811023
Ref: 419812811023
Ref: library/turtle turtle Shape12811318
Ref: 418b12811318
Ref: library/turtle turtle Shape addcomponent12812126
Ref: 418c12812126
Ref: library/turtle turtle Vec2D12812726
Ref: 417b12812726
Node: Explanation<2>12813278
Ref: library/turtle explanation12813409
Ref: 419a12813409
Ref: library/turtle turtle-explanation12813409
Ref: 410a12813409
Node: Help and configuration12814843
Ref: library/turtle help-and-configuration12814987
Ref: 419b12814987
Node: How to use help12815181
Ref: library/turtle how-to-use-help12815314
Ref: 419c12815314
Node: Translation of docstrings into different languages12817634
Ref: library/turtle translation-of-docstrings-into-different-languages12817811
Ref: 419d12817811
Ref: library/turtle turtle write_docstringdict12818117
Ref: 419e12818117
Node: How to configure Screen and Turtles12819150
Ref: library/turtle how-to-configure-screen-and-turtles12819303
Ref: 419f12819303
Node: turtledemo — Demo scripts12822101
Ref: library/turtle module-turtledemo12822255
Ref: 10212822255
Ref: library/turtle turtledemo-demo-scripts12822255
Ref: 41a012822255
Node: Changes since Python 2 612828864
Ref: library/turtle changes-since-python-2-612829020
Ref: 41a112829020
Node: Changes since Python 3 012830053
Ref: library/turtle changes-since-python-3-012830173
Ref: 41a212830173
Node: Development Tools12831417
Ref: library/development doc12831572
Ref: 41a312831572
Ref: library/development development12831572
Ref: 41a412831572
Ref: library/development development-tools12831572
Ref: 41a512831572
Ref: library/development translation-repo12831572
Ref: 41a612831572
Node: typing — Support for type hints12833502
Ref: library/typing doc12833654
Ref: 41a712833654
Ref: library/typing typing-support-for-type-hints12833654
Ref: 41a812833654
Ref: library/typing module-typing12833743
Ref: 10412833743
Ref: typing — Support for type hints-Footnote-112835875
Ref: typing — Support for type hints-Footnote-212835941
Ref: typing — Support for type hints-Footnote-312835993
Ref: typing — Support for type hints-Footnote-412836060
Ref: typing — Support for type hints-Footnote-512836117
Node: Specification for the Python Type System12836162
Ref: library/typing relevant-peps12836293
Ref: 41a912836293
Ref: library/typing specification-for-the-python-type-system12836293
Ref: 41aa12836293
Ref: Specification for the Python Type System-Footnote-112836558
Node: Type aliases12836618
Ref: library/typing id212836765
Ref: 41ab12836765
Ref: library/typing type-aliases12836765
Ref: 45712836765
Node: NewType12838270
Ref: library/typing distinct12838404
Ref: 41ac12838404
Ref: library/typing newtype12838404
Ref: 41ad12838404
Ref: NewType-Footnote-112841501
Node: Annotating callable objects12841543
Ref: library/typing annotating-callable-objects12841673
Ref: 41ae12841673
Ref: library/typing annotating-callables12841673
Ref: 242712841673
Ref: Annotating callable objects-Footnote-112844777
Node: Generics12844819
Ref: library/typing generics12844959
Ref: 212f12844959
Ref: library/typing id312844959
Ref: 41b012844959
Node: Annotating tuples12846264
Ref: library/typing annotating-tuples12846402
Ref: 242812846402
Ref: library/typing id412846402
Ref: 41b112846402
Node: The type of class objects12848781
Ref: library/typing the-type-of-class-objects12848947
Ref: 41b212848947
Ref: library/typing type-of-class-objects12848947
Ref: 41b312848947
Node: Annotating generators and coroutines12850626
Ref: library/typing annotating-generators-and-coroutines12850801
Ref: 26ea12850801
Ref: library/typing id512850801
Ref: 41b512850801
Node: User-defined generic types12853368
Ref: library/typing user-defined-generic-types12853530
Ref: 41b612853530
Ref: library/typing user-defined-generics12853530
Ref: 4d212853530
Ref: User-defined generic types-Footnote-112859438
Node: The Any type12859480
Ref: library/typing the-any-type12859637
Ref: 41b812859637
Node: Nominal vs structural subtyping12862238
Ref: library/typing nominal-vs-structural-subtyping12862387
Ref: 41b912862387
Ref: Nominal vs structural subtyping-Footnote-112864054
Ref: Nominal vs structural subtyping-Footnote-212864096
Ref: Nominal vs structural subtyping-Footnote-312864138
Node: Module contents<4>12864180
Ref: library/typing module-contents12864355
Ref: 41ba12864355
Node: Special typing primitives12864677
Ref: library/typing special-typing-primitives12864778
Ref: 41bb12864778
Node: Special types12864970
Ref: library/typing special-types12865067
Ref: 41bc12865067
Ref: library/typing typing Any12865210
Ref: 6af12865210
Ref: library/typing typing AnyStr12865589
Ref: 2b212865589
Ref: library/typing typing LiteralString12867404
Ref: 5cd12867404
Ref: library/typing typing Never12868628
Ref: 6ab12868628
Ref: library/typing typing NoReturn12868651
Ref: 41be12868651
Ref: library/typing typing Self12869879
Ref: 5ca12869879
Ref: library/typing typing TypeAlias12871810
Ref: 7cd12871810
Ref: Special types-Footnote-112873411
Ref: Special types-Footnote-212873453
Ref: Special types-Footnote-312873495
Ref: Special types-Footnote-412873545
Ref: Special types-Footnote-512873587
Node: Special forms12873629
Ref: library/typing special-forms12873774
Ref: 41bf12873774
Ref: library/typing typing Union12873944
Ref: 63e12873944
Ref: library/typing typing Optional12875361
Ref: 6b612875361
Ref: library/typing typing Concatenate12876172
Ref: 7c812876172
Ref: library/typing typing Literal12878560
Ref: 85b12878560
Ref: library/typing typing ClassVar12880654
Ref: 26612880654
Ref: library/typing typing Final12881825
Ref: 26712881825
Ref: library/typing typing Required12882566
Ref: 5c712882566
Ref: library/typing typing NotRequired12882834
Ref: 5c812882834
Ref: library/typing typing ReadOnly12883054
Ref: 16112883054
Ref: library/typing typing Annotated12883583
Ref: 94712883583
Ref: library/typing typing TypeIs12889346
Ref: 16312889346
Ref: library/typing typing TypeGuard12893152
Ref: 16412893152
Ref: library/typing typing Unpack12895573
Ref: 173812895573
Ref: Special forms-Footnote-112897280
Ref: Special forms-Footnote-212897322
Ref: Special forms-Footnote-312897364
Ref: Special forms-Footnote-412897406
Ref: Special forms-Footnote-512897448
Ref: Special forms-Footnote-612897490
Ref: Special forms-Footnote-712897532
Ref: Special forms-Footnote-812897574
Ref: Special forms-Footnote-912897616
Ref: Special forms-Footnote-1012897658
Ref: Special forms-Footnote-1112897701
Node: Building generic types and type aliases12897744
Ref: library/typing building-generic-types-and-type-aliases12897900
Ref: 41c112897900
Ref: library/typing typing Generic12898411
Ref: 15fb12898411
Ref: library/typing typevar12899616
Ref: 41b712899616
Ref: library/typing typing TypeVar12899616
Ref: 15d12899616
Ref: library/typing typing-constrained-typevar12903140
Ref: 41bd12903140
Ref: library/typing typing TypeVar __name__12903758
Ref: 41c212903758
Ref: library/typing typing TypeVar __covariant__12903830
Ref: 41c312903830
Ref: library/typing typing TypeVar __contravariant__12903938
Ref: 41c412903938
Ref: library/typing typing TypeVar __infer_variance__12904064
Ref: 41c512904064
Ref: library/typing typing TypeVar __bound__12904235
Ref: 41c612904235
Ref: library/typing typing TypeVar __constraints__12904591
Ref: 41c712904591
Ref: library/typing typing TypeVar __default__12904989
Ref: 41c812904989
Ref: library/typing typing TypeVar has_default12905171
Ref: 41c912905171
Ref: library/typing typevartuple12905818
Ref: 41c012905818
Ref: library/typing typing TypeVarTuple12905818
Ref: 15f12905818
Ref: library/typing typing TypeVarTuple __name__12910082
Ref: 41ca12910082
Ref: library/typing typing TypeVarTuple __default__12910160
Ref: 41cb12910160
Ref: library/typing typing TypeVarTuple has_default12910348
Ref: 41cc12910348
Ref: library/typing typing ParamSpec12910991
Ref: 15e12910991
Ref: library/typing typing ParamSpec args12913487
Ref: 41ce12913487
Ref: library/typing typing ParamSpec kwargs12913513
Ref: 41cf12913513
Ref: library/typing typing ParamSpec __name__12914277
Ref: 41d012914277
Ref: library/typing typing ParamSpec __default__12914359
Ref: 41d112914359
Ref: library/typing typing ParamSpec has_default12914551
Ref: 41d212914551
Ref: library/typing typing ParamSpecArgs12915892
Ref: 7ca12915892
Ref: library/typing typing ParamSpecKwargs12915923
Ref: 7cb12915923
Ref: library/typing typing TypeAliasType12916638
Ref: 45812916638
Ref: library/typing typing TypeAliasType __name__12916931
Ref: 41d312916931
Ref: library/typing typing TypeAliasType __module__12917094
Ref: 41d412917094
Ref: library/typing typing TypeAliasType __type_params__12917296
Ref: 41d512917296
Ref: library/typing typing TypeAliasType __value__12917667
Ref: 41d612917667
Ref: Building generic types and type aliases-Footnote-112918263
Ref: Building generic types and type aliases-Footnote-212918305
Ref: Building generic types and type aliases-Footnote-312918347
Ref: Building generic types and type aliases-Footnote-412918389
Ref: Building generic types and type aliases-Footnote-512918431
Ref: Building generic types and type aliases-Footnote-612918473
Ref: Building generic types and type aliases-Footnote-712918515
Node: Other special directives12918557
Ref: library/typing other-special-directives12918691
Ref: 41d712918691
Ref: library/typing typing NamedTuple12918917
Ref: 2b012918917
Ref: library/typing typing NewType12922263
Ref: d1c12922263
Ref: library/typing typing NewType __module__12922704
Ref: 41d812922704
Ref: library/typing typing NewType __name__12922804
Ref: 41d912922804
Ref: library/typing typing NewType __supertype__12922871
Ref: 41da12922871
Ref: library/typing typing Protocol12923076
Ref: 26412923076
Ref: library/typing typing runtime_checkable12924457
Ref: 44612924457
Ref: library/typing typing TypedDict12927132
Ref: 16212927132
Ref: library/typing typing TypedDict __total__12931871
Ref: 41db12931871
Ref: library/typing typing TypedDict __required_keys__12932935
Ref: 41dc12932935
Ref: library/typing typing TypedDict __optional_keys__12933007
Ref: 41dd12933007
Ref: library/typing typing TypedDict __readonly_keys__12934820
Ref: 41de12934820
Ref: library/typing typing TypedDict __mutable_keys__12935062
Ref: 41df12935062
Ref: Other special directives-Footnote-112936563
Ref: Other special directives-Footnote-212936605
Ref: Other special directives-Footnote-312936647
Ref: Other special directives-Footnote-412936689
Node: Protocols<3>12936731
Ref: library/typing protocols12936865
Ref: 41e012936865
Ref: library/typing typing SupportsAbs12937027
Ref: 41e112937027
Ref: library/typing typing SupportsBytes12937153
Ref: 5ed12937153
Ref: library/typing typing SupportsComplex12937241
Ref: 5ec12937241
Ref: library/typing typing SupportsFloat12937333
Ref: 41e212937333
Ref: library/typing typing SupportsIndex12937421
Ref: a5312937421
Ref: library/typing typing SupportsInt12937537
Ref: a5212937537
Ref: library/typing typing SupportsRound12937621
Ref: 41e312937621
Node: ABCs for working with IO12937751
Ref: library/typing abcs-for-working-with-io12937884
Ref: 41e412937884
Ref: library/typing typing IO12937955
Ref: 72e12937955
Ref: library/typing typing TextIO12937976
Ref: 41e512937976
Ref: library/typing typing BinaryIO12938001
Ref: 41e612938001
Node: Functions and decorators12938220
Ref: library/typing functions-and-decorators12938362
Ref: 41e712938362
Ref: library/typing typing cast12938433
Ref: 41cd12938433
Ref: library/typing typing assert_type12938734
Ref: 6ae12938734
Ref: library/typing typing assert_never12939829
Ref: 6aa12939829
Ref: library/typing typing reveal_type12941234
Ref: 6ad12941234
Ref: library/typing typing dataclass_transform12942428
Ref: 4d712942428
Ref: library/typing overload12948460
Ref: 41af12948460
Ref: library/typing typing overload12948460
Ref: 41e812948460
Ref: library/typing typing get_overloads12949991
Ref: 6b112949991
Ref: library/typing typing clear_overloads12950666
Ref: 6b212950666
Ref: library/typing typing final12950866
Ref: 6b012950866
Ref: library/typing typing no_type_check12952127
Ref: 6b712952127
Ref: library/typing typing no_type_check_decorator12952615
Ref: 2b112952615
Ref: library/typing typing override12953081
Ref: 44e12953081
Ref: library/typing typing type_check_only12954427
Ref: 41e912954427
Ref: Functions and decorators-Footnote-112955135
Ref: Functions and decorators-Footnote-212955203
Ref: Functions and decorators-Footnote-312955245
Ref: Functions and decorators-Footnote-412955287
Ref: Functions and decorators-Footnote-512955329
Node: Introspection helpers12955371
Ref: library/typing introspection-helpers12955497
Ref: 41ea12955497
Ref: library/typing typing get_type_hints12955562
Ref: 6b412955562
Ref: library/typing typing get_origin12958173
Ref: 2ec12958173
Ref: library/typing typing get_args12959033
Ref: 2ed12959033
Ref: library/typing typing get_protocol_members12959675
Ref: 26312959675
Ref: library/typing typing is_protocol12960133
Ref: 26512960133
Ref: library/typing typing is_typeddict12960439
Ref: 85c12960439
Ref: library/typing typing ForwardRef12960885
Ref: 197f12960885
Ref: library/typing typing NoDefault12961495
Ref: 26212961495
Ref: Introspection helpers-Footnote-112961883
Ref: Introspection helpers-Footnote-212961925
Node: Constant12961967
Ref: library/typing constant12962087
Ref: 41eb12962087
Ref: library/typing typing TYPE_CHECKING12962126
Ref: d1b12962126
Ref: library/typing generic-concrete-collections12963140
Ref: 41ec12963140
Ref: Constant-Footnote-112963176
Node: Deprecated aliases12963218
Ref: library/typing deprecated-aliases12963308
Ref: 41ed12963308
Ref: library/typing id612963308
Ref: 41ee12963308
Ref: Deprecated aliases-Footnote-112964892
Node: Aliases to built-in types12964934
Ref: library/typing aliases-to-built-in-types12965054
Ref: 41ef12965054
Ref: library/typing corresponding-to-built-in-types12965054
Ref: 41f012965054
Ref: library/typing typing Dict12965127
Ref: 41f112965127
Ref: library/typing typing List12965572
Ref: 41f212965572
Ref: library/typing typing Set12966040
Ref: 41f312966040
Ref: library/typing typing FrozenSet12966498
Ref: 41f412966498
Ref: library/typing typing Tuple12966781
Ref: 41f512966781
Ref: library/typing typing Type12967148
Ref: 41b412967148
Ref: Aliases to built-in types-Footnote-112967593
Ref: Aliases to built-in types-Footnote-212967635
Ref: Aliases to built-in types-Footnote-312967677
Ref: Aliases to built-in types-Footnote-412967719
Ref: Aliases to built-in types-Footnote-512967761
Ref: Aliases to built-in types-Footnote-612967803
Node: Aliases to types in collections12967845
Ref: library/typing aliases-to-types-in-collections12968005
Ref: 41f612968005
Ref: library/typing corresponding-to-types-in-collections12968005
Ref: 41f712968005
Ref: library/typing typing DefaultDict12968098
Ref: 41f812968098
Ref: library/typing typing OrderedDict12968454
Ref: 41f912968454
Ref: library/typing typing ChainMap12968808
Ref: 41fa12968808
Ref: library/typing typing Counter12969150
Ref: 41fb12969150
Ref: library/typing typing Deque12969470
Ref: 41fc12969470
Ref: Aliases to types in collections-Footnote-112969810
Ref: Aliases to types in collections-Footnote-212969852
Ref: Aliases to types in collections-Footnote-312969894
Ref: Aliases to types in collections-Footnote-412969936
Ref: Aliases to types in collections-Footnote-512969978
Node: Aliases to other concrete types12970020
Ref: library/typing aliases-to-other-concrete-types12970199
Ref: 41fd12970199
Ref: library/typing other-concrete-types12970199
Ref: 41fe12970199
Ref: library/typing typing Pattern12970284
Ref: 72f12970284
Ref: library/typing typing Match12970310
Ref: 41ff12970310
Ref: library/typing typing Text12970891
Ref: 30b12970891
Ref: library/typing abstract-base-classes12971653
Ref: 420012971653
Ref: Aliases to other concrete types-Footnote-112971689
Node: Aliases to container ABCs in collections abc12971731
Ref: library/typing aliases-to-container-abcs-in-collections-abc12971926
Ref: 420112971926
Ref: library/typing corresponding-to-collections-in-collections-abc12971926
Ref: 420212971926
Ref: library/typing typing AbstractSet12972045
Ref: 420312972045
Ref: library/typing typing ByteString12972322
Ref: 2ee12972322
Ref: library/typing typing Collection12973384
Ref: d1a12973384
Ref: library/typing typing Container12973722
Ref: 420412973722
Ref: library/typing typing ItemsView12974006
Ref: 420512974006
Ref: library/typing typing KeysView12974332
Ref: 420612974332
Ref: library/typing typing Mapping12974631
Ref: 420712974631
Ref: library/typing typing MappingView12974928
Ref: 420812974928
Ref: library/typing typing MutableMapping12975210
Ref: 420912975210
Ref: library/typing typing MutableSequence12975511
Ref: 420a12975511
Ref: library/typing typing MutableSet12975810
Ref: 420b12975810
Ref: library/typing typing Sequence12976099
Ref: 420c12976099
Ref: library/typing typing ValuesView12976402
Ref: 420d12976402
Ref: Aliases to container ABCs in collections abc-Footnote-112976744
Ref: Aliases to container ABCs in collections abc-Footnote-212976786
Ref: Aliases to container ABCs in collections abc-Footnote-312976844
Ref: Aliases to container ABCs in collections abc-Footnote-412976886
Ref: Aliases to container ABCs in collections abc-Footnote-512976928
Ref: Aliases to container ABCs in collections abc-Footnote-612976970
Ref: Aliases to container ABCs in collections abc-Footnote-712977012
Ref: Aliases to container ABCs in collections abc-Footnote-812977054
Ref: Aliases to container ABCs in collections abc-Footnote-912977096
Ref: Aliases to container ABCs in collections abc-Footnote-1012977138
Ref: Aliases to container ABCs in collections abc-Footnote-1112977181
Ref: Aliases to container ABCs in collections abc-Footnote-1212977224
Ref: Aliases to container ABCs in collections abc-Footnote-1312977267
Node: Aliases to asynchronous ABCs in collections abc12977310
Ref: library/typing aliases-to-asynchronous-abcs-in-collections-abc12977514
Ref: 420e12977514
Ref: library/typing asynchronous-programming12977514
Ref: 420f12977514
Ref: library/typing typing Coroutine12977639
Ref: 1ad812977639
Ref: library/typing typing AsyncGenerator12978188
Ref: 173612978188
Ref: library/typing typing AsyncIterable12978837
Ref: 421012978837
Ref: library/typing typing AsyncIterator12979161
Ref: 421112979161
Ref: library/typing typing Awaitable12979491
Ref: 421212979491
Ref: Aliases to asynchronous ABCs in collections abc-Footnote-112979839
Ref: Aliases to asynchronous ABCs in collections abc-Footnote-212979881
Ref: Aliases to asynchronous ABCs in collections abc-Footnote-312979923
Ref: Aliases to asynchronous ABCs in collections abc-Footnote-412979965
Ref: Aliases to asynchronous ABCs in collections abc-Footnote-512980007
Node: Aliases to other ABCs in collections abc12980049
Ref: library/typing aliases-to-other-abcs-in-collections-abc12980235
Ref: 421312980235
Ref: library/typing corresponding-to-other-types-in-collections-abc12980235
Ref: 421412980235
Ref: library/typing typing Iterable12980346
Ref: 421512980346
Ref: library/typing typing Iterator12980627
Ref: 421612980627
Ref: library/typing typing Callable12980909
Ref: 7c912980909
Ref: library/typing typing Generator12981490
Ref: 173512981490
Ref: library/typing typing Hashable12982100
Ref: 4f612982100
Ref: library/typing typing Reversible12982292
Ref: 421712982292
Ref: library/typing typing Sized12982578
Ref: 4f712982578
Ref: Aliases to other ABCs in collections abc-Footnote-112982797
Ref: Aliases to other ABCs in collections abc-Footnote-212982839
Ref: Aliases to other ABCs in collections abc-Footnote-312982881
Ref: Aliases to other ABCs in collections abc-Footnote-412982923
Ref: Aliases to other ABCs in collections abc-Footnote-512982965
Ref: Aliases to other ABCs in collections abc-Footnote-612983007
Node: Aliases to contextlib ABCs12983049
Ref: library/typing aliases-to-contextlib-abcs12983179
Ref: 421812983179
Ref: library/typing context-manager-types12983179
Ref: 421912983179
Ref: library/typing typing ContextManager12983262
Ref: cb212983262
Ref: library/typing typing AsyncContextManager12983984
Ref: 173312983984
Ref: Aliases to contextlib ABCs-Footnote-112984773
Ref: Aliases to contextlib ABCs-Footnote-212984815
Node: Deprecation Timeline of Major Features12984857
Ref: library/typing deprecation-timeline-of-major-features12984992
Ref: 421a12984992
Ref: Deprecation Timeline of Major Features-Footnote-112987748
Ref: Deprecation Timeline of Major Features-Footnote-212987790
Ref: Deprecation Timeline of Major Features-Footnote-312987845
Ref: Deprecation Timeline of Major Features-Footnote-412987900
Ref: Deprecation Timeline of Major Features-Footnote-512987955
Ref: Deprecation Timeline of Major Features-Footnote-612987997
Ref: Deprecation Timeline of Major Features-Footnote-712988053
Node: pydoc — Documentation generator and online help system12988109
Ref: library/pydoc doc12988293
Ref: 421b12988293
Ref: library/pydoc module-pydoc12988293
Ref: b512988293
Ref: library/pydoc pydoc-documentation-generator-and-online-help-system12988293
Ref: 421c12988293
Ref: library/pydoc translation-repo12988293
Ref: 421d12988293
Ref: pydoc — Documentation generator and online help system-Footnote-112993282
Node: Python Development Mode12993347
Ref: library/devmode doc12993542
Ref: 421e12993542
Ref: library/devmode devmode12993542
Ref: 1f812993542
Ref: library/devmode python-development-mode12993542
Ref: 421f12993542
Ref: library/devmode translation-repo12993542
Ref: 422012993542
Node: Effects of the Python Development Mode12994177
Ref: library/devmode effects-of-the-python-development-mode12994307
Ref: 422112994307
Node: ResourceWarning Example12997999
Ref: library/devmode resourcewarning-example12998171
Ref: 422212998171
Node: Bad file descriptor error example13000083
Ref: library/devmode bad-file-descriptor-error-example13000208
Ref: 422313000208
Ref: Bad file descriptor error example-Footnote-113001743
Node: doctest — Test interactive Python examples13001808
Ref: library/doctest doc13001982
Ref: 422413001982
Ref: library/doctest doctest-test-interactive-python-examples13001982
Ref: 422513001982
Ref: library/doctest module-doctest13001982
Ref: 3a13001982
Ref: library/doctest translation-repo13001982
Ref: 422613001982
Ref: doctest — Test interactive Python examples-Footnote-113006100
Node: Simple Usage Checking Examples in Docstrings13006167
Ref: library/doctest doctest-simple-testmod13006346
Ref: 422713006346
Ref: library/doctest simple-usage-checking-examples-in-docstrings13006346
Ref: 422813006346
Node: Simple Usage Checking Examples in a Text File13007762
Ref: library/doctest doctest-simple-testfile13007968
Ref: 422b13007968
Ref: library/doctest simple-usage-checking-examples-in-a-text-file13007968
Ref: 422c13007968
Node: Command-line Usage13010014
Ref: library/doctest command-line-usage13010188
Ref: 422e13010188
Ref: library/doctest doctest-cli13010188
Ref: 422913010188
Ref: library/doctest cmdoption-doctest-v13010383
Ref: 422f13010383
Ref: library/doctest cmdoption-doctest-verbose13010383
Ref: 423013010383
Ref: library/doctest cmdoption-doctest-o13010991
Ref: 423113010991
Ref: library/doctest cmdoption-doctest-option13010991
Ref: 423213010991
Ref: library/doctest cmdoption-doctest-f13011164
Ref: 423313011164
Ref: library/doctest cmdoption-doctest-fail-fast13011164
Ref: 423413011164
Node: How It Works13011269
Ref: library/doctest doctest-how-it-works13011407
Ref: 423513011407
Ref: library/doctest how-it-works13011407
Ref: 423613011407
Node: Which Docstrings Are Examined?13012062
Ref: library/doctest doctest-which-docstrings13012188
Ref: 423713012188
Ref: library/doctest which-docstrings-are-examined13012188
Ref: 423813012188
Ref: library/doctest module __test__13012404
Ref: 423913012404
Node: How are Docstring Examples Recognized?13014000
Ref: library/doctest doctest-finding-examples13014166
Ref: 423a13014166
Ref: library/doctest how-are-docstring-examples-recognized13014166
Ref: 423b13014166
Node: What’s the Execution Context?13017282
Ref: library/doctest doctest-execution-context13017440
Ref: 423f13017440
Ref: library/doctest what-s-the-execution-context13017440
Ref: 424013017440
Node: What About Exceptions?13018153
Ref: library/doctest doctest-exceptions13018285
Ref: 424113018285
Ref: library/doctest what-about-exceptions13018285
Ref: 424213018285
Ref: library/doctest option-flags-and-directives13022832
Ref: 424313022832
Ref: What About Exceptions?-Footnote-113022869
Node: Option Flags13023069
Ref: library/doctest doctest-options13023180
Ref: f6b13023180
Ref: library/doctest option-flags13023180
Ref: 424413023180
Ref: library/doctest doctest DONT_ACCEPT_TRUE_FOR_113023743
Ref: 424513023743
Ref: library/doctest doctest DONT_ACCEPT_BLANKLINE13024371
Ref: 424613024371
Ref: library/doctest doctest NORMALIZE_WHITESPACE13024824
Ref: 423c13024824
Ref: library/doctest doctest ELLIPSIS13025314
Ref: 14bd13025314
Ref: library/doctest doctest IGNORE_EXCEPTION_DETAIL13025750
Ref: 135213025750
Ref: library/doctest doctest SKIP13027214
Ref: 424713027214
Ref: library/doctest doctest COMPARISON_FLAGS13027728
Ref: 424813027728
Ref: library/doctest doctest REPORT_UDIFF13027900
Ref: 14be13027900
Ref: library/doctest doctest REPORT_CDIFF13028056
Ref: 14bf13028056
Ref: library/doctest doctest REPORT_NDIFF13028216
Ref: 14c013028216
Ref: library/doctest doctest REPORT_ONLY_FIRST_FAILURE13028680
Ref: 424913028680
Ref: library/doctest doctest FAIL_FAST13029259
Ref: f6c13029259
Ref: library/doctest doctest REPORTING_FLAGS13029597
Ref: 424a13029597
Ref: library/doctest doctest register_optionflag13029849
Ref: 424b13029849
Node: Directives13030324
Ref: library/doctest directives13030424
Ref: 424e13030424
Ref: library/doctest doctest-directives13030424
Ref: 423d13030424
Ref: library/doctest grammar-token-doctest-directive13030651
Ref: 424f13030651
Ref: library/doctest grammar-token-doctest-directive_options13030728
Ref: 425013030728
Ref: library/doctest grammar-token-doctest-directive_option13030826
Ref: 425113030826
Ref: library/doctest grammar-token-doctest-on_or_off13030915
Ref: 425213030915
Ref: library/doctest grammar-token-doctest-directive_option_name13030956
Ref: 425313030956
Node: Warnings<2>13033057
Ref: library/doctest doctest-warnings13033136
Ref: 425413033136
Ref: library/doctest warnings13033136
Ref: 425513033136
Node: Basic API13034882
Ref: library/doctest basic-api13035014
Ref: 425613035014
Ref: library/doctest doctest-basic-api13035014
Ref: 422a13035014
Ref: library/doctest doctest testfile13035398
Ref: 422d13035398
Ref: library/doctest doctest testmod13039343
Ref: 14bc13039343
Ref: library/doctest doctest run_docstring_examples13041060
Ref: 425813041060
Node: Unittest API13042038
Ref: library/doctest doctest-unittest-api13042170
Ref: 425913042170
Ref: library/doctest unittest-api13042170
Ref: 425a13042170
Ref: library/doctest doctest DocFileSuite13042934
Ref: 425c13042934
Ref: library/doctest doctest DocTestSuite13046795
Ref: e2513046795
Ref: library/doctest doctest set_unittest_reportflags13050112
Ref: 425f13050112
Node: Advanced API13051281
Ref: library/doctest advanced-api13051413
Ref: 426013051413
Ref: library/doctest doctest-advanced-api13051413
Ref: 426113051413
Node: DocTest Objects13053578
Ref: library/doctest doctest-doctest13053666
Ref: 426313053666
Ref: library/doctest doctest-objects13053666
Ref: 426413053666
Ref: library/doctest doctest DocTest13053719
Ref: 17c213053719
Ref: library/doctest doctest DocTest examples13054123
Ref: 426513054123
Ref: library/doctest doctest DocTest globs13054298
Ref: 425e13054298
Ref: library/doctest doctest DocTest name13054633
Ref: 426613054633
Ref: library/doctest doctest DocTest filename13054820
Ref: 426713054820
Ref: library/doctest doctest DocTest lineno13055043
Ref: 162613055043
Ref: library/doctest doctest DocTest docstring13055313
Ref: 426813055313
Node: Example Objects13055512
Ref: library/doctest doctest-example13055630
Ref: 426913055630
Ref: library/doctest example-objects13055630
Ref: 426a13055630
Ref: library/doctest doctest Example13055683
Ref: 426213055683
Ref: library/doctest doctest Example source13056110
Ref: 426b13056110
Ref: library/doctest doctest Example want13056354
Ref: 426c13056354
Ref: library/doctest doctest Example exc_msg13056705
Ref: 426d13056705
Ref: library/doctest doctest Example lineno13057189
Ref: 426e13057189
Ref: library/doctest doctest Example indent13057420
Ref: 426f13057420
Ref: library/doctest doctest Example options13057613
Ref: 427013057613
Node: DocTestFinder objects13058025
Ref: library/doctest doctest-doctestfinder13058149
Ref: 427113058149
Ref: library/doctest doctestfinder-objects13058149
Ref: 427213058149
Ref: library/doctest doctest DocTestFinder13058214
Ref: 173b13058214
Ref: library/doctest doctest DocTestFinder find13059339
Ref: 180e13059339
Node: DocTestParser objects13061463
Ref: library/doctest doctest-doctestparser13061591
Ref: 427313061591
Ref: library/doctest doctestparser-objects13061591
Ref: 427413061591
Ref: library/doctest doctest DocTestParser13061656
Ref: 423e13061656
Ref: library/doctest doctest DocTestParser get_doctest13061883
Ref: 427513061883
Ref: library/doctest doctest DocTestParser get_examples13062271
Ref: 427613062271
Ref: library/doctest doctest DocTestParser parse13062609
Ref: 427713062609
Node: TestResults objects13062997
Ref: library/doctest testresults-objects13063125
Ref: 427813063125
Ref: library/doctest doctest TestResults13063186
Ref: 427913063186
Ref: library/doctest doctest TestResults failed13063238
Ref: 427a13063238
Ref: library/doctest doctest TestResults attempted13063301
Ref: 427b13063301
Ref: library/doctest doctest TestResults skipped13063370
Ref: 1de13063370
Node: DocTestRunner objects13063469
Ref: library/doctest doctest-doctestrunner13063597
Ref: 427c13063597
Ref: library/doctest doctestrunner-objects13063597
Ref: 427d13063597
Ref: library/doctest doctest DocTestRunner13063662
Ref: 424d13063662
Ref: library/doctest doctest DocTestRunner report_start13066080
Ref: 427e13066080
Ref: library/doctest doctest DocTestRunner report_success13066571
Ref: 427f13066571
Ref: library/doctest doctest DocTestRunner report_failure13067096
Ref: 428113067096
Ref: library/doctest doctest DocTestRunner report_unexpected_exception13067611
Ref: 428013067611
Ref: library/doctest doctest DocTestRunner run13068268
Ref: 1dc13068268
Ref: library/doctest doctest DocTestRunner summarize13069331
Ref: 425713069331
Ref: library/doctest doctest DocTestRunner tries13069785
Ref: 428213069785
Ref: library/doctest doctest DocTestRunner failures13069853
Ref: 428313069853
Ref: library/doctest doctest DocTestRunner skips13069921
Ref: 1dd13069921
Node: OutputChecker objects13070021
Ref: library/doctest doctest-outputchecker13070121
Ref: 428413070121
Ref: library/doctest outputchecker-objects13070121
Ref: 428513070121
Ref: library/doctest doctest OutputChecker13070186
Ref: 424c13070186
Ref: library/doctest doctest OutputChecker check_output13070668
Ref: 428613070668
Ref: library/doctest doctest OutputChecker output_difference13071155
Ref: 428713071155
Node: Debugging13071470
Ref: library/doctest debugging13071597
Ref: 428813071597
Ref: library/doctest doctest-debugging13071597
Ref: 428913071597
Ref: library/doctest doctest script_from_examples13073696
Ref: 428c13073696
Ref: library/doctest doctest testsource13074683
Ref: 428d13074683
Ref: library/doctest doctest debug13075480
Ref: 428b13075480
Ref: library/doctest doctest debug_src13076571
Ref: 428f13076571
Ref: library/doctest doctest DebugRunner13077438
Ref: 428a13077438
Ref: library/doctest doctest DocTestFailure13078215
Ref: 429113078215
Ref: library/doctest doctest DocTestFailure test13078578
Ref: 429213078578
Ref: library/doctest doctest DocTestFailure example13078701
Ref: 429313078701
Ref: library/doctest doctest DocTestFailure got13078784
Ref: 429413078784
Ref: library/doctest doctest UnexpectedException13078856
Ref: 429013078856
Ref: library/doctest doctest UnexpectedException test13079209
Ref: 429513079209
Ref: library/doctest doctest UnexpectedException example13079337
Ref: 429613079337
Ref: library/doctest doctest UnexpectedException exc_info13079425
Ref: 429713079425
Node: Soapbox13079586
Ref: library/doctest doctest-soapbox13079692
Ref: 429813079692
Ref: library/doctest soapbox13079692
Ref: 429913079692
Node: unittest — Unit testing framework13083523
Ref: library/unittest doc13083711
Ref: 429a13083711
Ref: library/unittest module-unittest13083711
Ref: 10613083711
Ref: library/unittest translation-repo13083711
Ref: 429b13083711
Ref: library/unittest unittest-unit-testing-framework13083711
Ref: 429c13083711
Ref: unittest — Unit testing framework-Footnote-113086848
Ref: unittest — Unit testing framework-Footnote-213086926
Ref: unittest — Unit testing framework-Footnote-313087019
Ref: unittest — Unit testing framework-Footnote-413087052
Ref: unittest — Unit testing framework-Footnote-513087116
Ref: unittest — Unit testing framework-Footnote-613087174
Ref: unittest — Unit testing framework-Footnote-713087204
Ref: unittest — Unit testing framework-Footnote-813087236
Ref: unittest — Unit testing framework-Footnote-913087280
Node: Basic example13087314
Ref: library/unittest basic-example13087433
Ref: 429e13087433
Ref: library/unittest unittest-minimal-example13087433
Ref: 429f13087433
Node: Command-Line Interface<2>13090406
Ref: library/unittest command-line-interface13090548
Ref: 42a113090548
Ref: library/unittest unittest-command-line-interface13090548
Ref: 42a213090548
Node: Command-line options<4>13091944
Ref: library/unittest command-line-options13092029
Ref: 42a413092029
Ref: library/unittest cmdoption-unittest-b13092143
Ref: 137c13092143
Ref: library/unittest cmdoption-unittest-buffer13092143
Ref: 42a513092143
Ref: library/unittest cmdoption-unittest-c13092402
Ref: 137d13092402
Ref: library/unittest cmdoption-unittest-catch13092402
Ref: 42a613092402
Ref: library/unittest cmdoption-unittest-f13092746
Ref: 137f13092746
Ref: library/unittest cmdoption-unittest-failfast13092746
Ref: 42a813092746
Ref: library/unittest cmdoption-unittest-k13092829
Ref: 42a913092829
Ref: library/unittest cmdoption-unittest-locals13093541
Ref: 42aa13093541
Ref: library/unittest cmdoption-unittest-durations13093605
Ref: 42ab13093605
Node: Test Discovery13094077
Ref: library/unittest test-discovery13094226
Ref: 42ac13094226
Ref: library/unittest unittest-test-discovery13094226
Ref: 42a313094226
Ref: library/unittest cmdoption-unittest-discover-v13095082
Ref: 42ad13095082
Ref: library/unittest cmdoption-unittest-discover-verbose13095082
Ref: 42ae13095082
Ref: library/unittest cmdoption-unittest-discover-s13095130
Ref: 42af13095130
Ref: library/unittest cmdoption-unittest-discover-start-directory13095130
Ref: 42b013095130
Ref: library/unittest cmdoption-unittest-discover-p13095228
Ref: 42b113095228
Ref: library/unittest cmdoption-unittest-discover-pattern13095228
Ref: 42b213095228
Ref: library/unittest cmdoption-unittest-discover-t13095322
Ref: 42b313095322
Ref: library/unittest cmdoption-unittest-discover-top-level-directory13095322
Ref: 42b413095322
Node: Organizing test code13097735
Ref: library/unittest organizing-test-code13097881
Ref: 42b613097881
Ref: library/unittest organizing-tests13097881
Ref: 42a013097881
Node: Re-using old test code13102634
Ref: library/unittest legacy-unit-tests13102802
Ref: 42b713102802
Ref: library/unittest re-using-old-test-code13102802
Ref: 42b813102802
Node: Skipping tests and expected failures13104321
Ref: library/unittest skipping-tests-and-expected-failures13104514
Ref: 42b913104514
Ref: library/unittest unittest-skipping13104514
Ref: 42ba13104514
Ref: library/unittest unittest skip13107673
Ref: 1b6913107673
Ref: library/unittest unittest skipIf13107821
Ref: 42bd13107821
Ref: library/unittest unittest skipUnless13107927
Ref: 42be13107927
Ref: library/unittest unittest expectedFailure13108041
Ref: 42bc13108041
Ref: library/unittest unittest SkipTest13108350
Ref: 101f13108350
Node: Distinguishing test iterations using subtests13108854
Ref: library/unittest distinguishing-test-iterations-using-subtests13109046
Ref: 42bf13109046
Ref: library/unittest subtests13109046
Ref: 101d13109046
Node: Classes and functions13111650
Ref: library/unittest classes-and-functions13111831
Ref: 42c013111831
Ref: library/unittest unittest-contents13111831
Ref: 42c113111831
Node: Test cases13112028
Ref: library/unittest test-cases13112119
Ref: 42c213112119
Ref: library/unittest testcase-objects13112119
Ref: 42c313112119
Ref: library/unittest unittest TestCase13112162
Ref: 45113112162
Ref: library/unittest unittest TestCase setUp13113433
Ref: 138413113433
Ref: library/unittest unittest TestCase tearDown13113811
Ref: 138513113811
Ref: library/unittest unittest TestCase setUpClass13114586
Ref: a5c13114586
Ref: library/unittest unittest TestCase tearDownClass13115027
Ref: 138213115027
Ref: library/unittest unittest TestCase run13115477
Ref: 11aa13115477
Ref: library/unittest unittest TestCase skipTest13116093
Ref: 42bb13116093
Ref: library/unittest unittest TestCase subTest13116352
Ref: 101c13116352
Ref: library/unittest unittest TestCase debug13116910
Ref: 19ef13116910
Ref: library/unittest assert-methods13117145
Ref: 429d13117145
Ref: library/unittest unittest TestCase assertEqual13120984
Ref: 52c13120984
Ref: library/unittest unittest TestCase assertNotEqual13121856
Ref: 52d13121856
Ref: library/unittest unittest TestCase assertTrue13122035
Ref: 52a13122035
Ref: library/unittest unittest TestCase assertFalse13122080
Ref: 52b13122080
Ref: library/unittest unittest TestCase assertIs13122581
Ref: 138613122581
Ref: library/unittest unittest TestCase assertIsNot13122633
Ref: 138713122633
Ref: library/unittest unittest TestCase assertIsNone13122808
Ref: 12d113122808
Ref: library/unittest unittest TestCase assertIsNotNone13122855
Ref: 12d213122855
Ref: library/unittest unittest TestCase assertIn13122994
Ref: 138f13122994
Ref: library/unittest unittest TestCase assertNotIn13123050
Ref: 139013123050
Ref: library/unittest unittest TestCase assertIsInstance13123204
Ref: 138813123204
Ref: library/unittest unittest TestCase assertNotIsInstance13123259
Ref: 138913123259
Ref: library/unittest unittest TestCase assertRaises13126446
Ref: 53013126446
Ref: library/unittest unittest TestCase assertRaisesRegex13128156
Ref: 53213128156
Ref: library/unittest unittest TestCase assertWarns13129151
Ref: 11a813129151
Ref: library/unittest unittest TestCase assertWarnsRegex13130854
Ref: 11a913130854
Ref: library/unittest unittest TestCase assertLogs13131794
Ref: 85f13131794
Ref: library/unittest unittest TestCase records13132870
Ref: 42c713132870
Ref: library/unittest unittest TestCase output13133014
Ref: 42c813133014
Ref: library/unittest unittest TestCase assertNoLogs13133563
Ref: 85e13133563
Ref: library/unittest unittest TestCase assertAlmostEqual13137137
Ref: 52e13137137
Ref: library/unittest unittest TestCase assertNotAlmostEqual13137235
Ref: 52f13137235
Ref: library/unittest unittest TestCase assertGreater13138284
Ref: 138a13138284
Ref: library/unittest unittest TestCase assertGreaterEqual13138341
Ref: 138b13138341
Ref: library/unittest unittest TestCase assertLess13138403
Ref: 138c13138403
Ref: library/unittest unittest TestCase assertLessEqual13138457
Ref: 138d13138457
Ref: library/unittest unittest TestCase assertRegex13138824
Ref: 53113138824
Ref: library/unittest unittest TestCase assertNotRegex13138877
Ref: 53313138877
Ref: library/unittest unittest TestCase assertCountEqual13139609
Ref: 127013139609
Ref: library/unittest type-specific-methods13140272
Ref: 42c613140272
Ref: library/unittest unittest TestCase addTypeEqualityFunc13140591
Ref: 139313140591
Ref: library/unittest unittest TestCase assertMultiLineEqual13143331
Ref: 138e13143331
Ref: library/unittest unittest TestCase assertSequenceEqual13143748
Ref: 12d013143748
Ref: library/unittest unittest TestCase assertListEqual13144377
Ref: 12ce13144377
Ref: library/unittest unittest TestCase assertTupleEqual13144436
Ref: 12cf13144436
Ref: library/unittest unittest TestCase assertSetEqual13144886
Ref: 12cc13144886
Ref: library/unittest unittest TestCase assertDictEqual13145343
Ref: 12cd13145343
Ref: library/unittest other-methods-and-attrs13145703
Ref: 42c913145703
Ref: library/unittest unittest TestCase fail13145788
Ref: 42ca13145788
Ref: library/unittest unittest TestCase failureException13145931
Ref: 425d13145931
Ref: library/unittest unittest TestCase longMessage13146346
Ref: 138013146346
Ref: library/unittest unittest TestCase maxDiff13147086
Ref: 127113147086
Ref: library/unittest unittest TestCase countTestCases13147782
Ref: 42cb13147782
Ref: library/unittest unittest TestCase defaultTestResult13147958
Ref: 42c513147958
Ref: library/unittest unittest TestCase id13148378
Ref: 42cc13148378
Ref: library/unittest unittest TestCase shortDescription13148573
Ref: 42cd13148573
Ref: library/unittest unittest TestCase addCleanup13149192
Ref: a9013149192
Ref: library/unittest unittest TestCase enterContext13149794
Ref: 6bc13149794
Ref: library/unittest unittest TestCase doCleanups13150123
Ref: 138313150123
Ref: library/unittest unittest TestCase addClassCleanup13150748
Ref: a5a13150748
Ref: library/unittest unittest TestCase enterClassContext13151408
Ref: 6bd13151408
Ref: library/unittest unittest TestCase doClassCleanups13151759
Ref: 42ce13151759
Ref: library/unittest unittest IsolatedAsyncioTestCase13152435
Ref: 30c13152435
Ref: library/unittest unittest IsolatedAsyncioTestCase loop_factory13152648
Ref: 42cf13152648
Ref: library/unittest unittest IsolatedAsyncioTestCase asyncSetUp13152904
Ref: 42d013152904
Ref: library/unittest unittest IsolatedAsyncioTestCase asyncTearDown13153355
Ref: 42d113153355
Ref: library/unittest unittest IsolatedAsyncioTestCase addAsyncCleanup13154202
Ref: 42d213154202
Ref: library/unittest unittest IsolatedAsyncioTestCase enterAsyncContext13154360
Ref: 6be13154360
Ref: library/unittest unittest IsolatedAsyncioTestCase run13154721
Ref: 42d313154721
Ref: library/unittest unittest FunctionTestCase13156459
Ref: 181813156459
Node: Grouping tests13156931
Ref: library/unittest grouping-tests13157056
Ref: 42d413157056
Ref: library/unittest testsuite-objects13157056
Ref: 42d513157056
Ref: library/unittest unittest TestSuite13157107
Ref: e2613157107
Ref: library/unittest unittest TestSuite addTest13158036
Ref: 42d613158036
Ref: library/unittest unittest TestSuite addTests13158140
Ref: 42d713158140
Ref: library/unittest unittest TestSuite run13158499
Ref: 42d813158499
Ref: library/unittest unittest TestSuite debug13158795
Ref: 42d913158795
Ref: library/unittest unittest TestSuite countTestCases13159068
Ref: 42da13159068
Ref: library/unittest unittest TestSuite __iter__13159232
Ref: 106413159232
Node: Loading and running tests13160627
Ref: library/unittest loading-and-running-tests13160733
Ref: 42db13160733
Ref: library/unittest unittest TestLoader13160806
Ref: 28e13160806
Ref: library/unittest unittest TestLoader errors13161282
Ref: ec013161282
Ref: library/unittest unittest TestLoader loadTestsFromTestCase13161745
Ref: 29013161745
Ref: library/unittest unittest TestLoader loadTestsFromModule13162278
Ref: 28f13162278
Ref: library/unittest unittest TestLoader loadTestsFromName13163668
Ref: 139113163668
Ref: library/unittest unittest TestLoader loadTestsFromNames13165462
Ref: 42dd13165462
Ref: library/unittest unittest TestLoader getTestCaseNames13165748
Ref: 29113165748
Ref: library/unittest unittest TestLoader discover13165951
Ref: 102013165951
Ref: library/unittest unittest TestLoader testMethodPrefix13169223
Ref: 42de13169223
Ref: library/unittest unittest TestLoader sortTestMethodsUsing13169509
Ref: 42df13169509
Ref: library/unittest unittest TestLoader suiteClass13169720
Ref: 139213169720
Ref: library/unittest unittest TestLoader testNamePatterns13170015
Ref: 42e013170015
Ref: library/unittest unittest TestResult13170729
Ref: 11ab13170729
Ref: library/unittest unittest TestResult errors13171551
Ref: 42e113171551
Ref: library/unittest unittest TestResult failures13171781
Ref: 42e213171781
Ref: library/unittest unittest TestResult skipped13172065
Ref: 42e313172065
Ref: library/unittest unittest TestResult expectedFailures13172263
Ref: 42e413172263
Ref: library/unittest unittest TestResult unexpectedSuccesses13172505
Ref: 42e513172505
Ref: library/unittest unittest TestResult collectedDurations13172670
Ref: 181b13172670
Ref: library/unittest unittest TestResult shouldStop13172880
Ref: 42e613172880
Ref: library/unittest unittest TestResult testsRun13173014
Ref: 42e813173014
Ref: library/unittest unittest TestResult buffer13173093
Ref: 42e913173093
Ref: library/unittest unittest TestResult failfast13173544
Ref: 42ec13173544
Ref: library/unittest unittest TestResult tb_locals13173731
Ref: 42ed13173731
Ref: library/unittest unittest TestResult wasSuccessful13173881
Ref: 42ee13173881
Ref: library/unittest unittest TestResult stop13174218
Ref: 42e713174218
Ref: library/unittest unittest TestResult startTest13175171
Ref: 42ea13175171
Ref: library/unittest unittest TestResult stopTest13175270
Ref: 42eb13175270
Ref: library/unittest unittest TestResult startTestRun13175405
Ref: 139513175405
Ref: library/unittest unittest TestResult stopTestRun13175526
Ref: 139613175526
Ref: library/unittest unittest TestResult addError13175645
Ref: 19f213175645
Ref: library/unittest unittest TestResult addFailure13176112
Ref: 19f113176112
Ref: library/unittest unittest TestResult addSuccess13176570
Ref: 42ef13176570
Ref: library/unittest unittest TestResult addSkip13176712
Ref: 19f313176712
Ref: library/unittest unittest TestResult addExpectedFailure13177008
Ref: 42f013177008
Ref: library/unittest unittest TestResult addUnexpectedSuccess13177434
Ref: 42f113177434
Ref: library/unittest unittest TestResult addSubTest13177740
Ref: 19f413177740
Ref: library/unittest unittest TestResult addDuration13178414
Ref: 185b13178414
Ref: library/unittest unittest TextTestResult13178660
Ref: 53413178660
Ref: library/unittest unittest defaultTestLoader13179059
Ref: 42dc13179059
Ref: library/unittest unittest TextTestRunner13179308
Ref: 185a13179308
Ref: library/unittest unittest TextTestRunner _makeResult13180721
Ref: 42f313180721
Ref: library/unittest unittest TextTestRunner run13181372
Ref: 42f413181372
Ref: library/unittest unittest main13181734
Ref: 101e13181734
Node: load_tests Protocol13184680
Ref: library/unittest id113184761
Ref: 42b513184761
Ref: library/unittest load-tests-protocol13184761
Ref: 425b13184761
Node: Class and Module Fixtures13187436
Ref: library/unittest class-and-module-fixtures13187587
Ref: 42c413187587
Node: setUpClass and tearDownClass13189488
Ref: library/unittest setupclass-and-teardownclass13189617
Ref: 42f513189617
Node: setUpModule and tearDownModule13190532
Ref: library/unittest setupmodule-and-teardownmodule13190661
Ref: 42f613190661
Ref: library/unittest unittest setUpModule13190744
Ref: a5b13190744
Ref: library/unittest unittest addModuleCleanup13191275
Ref: a5913191275
Ref: library/unittest unittest enterModuleContext13191880
Ref: 6bf13191880
Ref: library/unittest unittest doModuleCleanups13192202
Ref: 197813192202
Node: Signal Handling13192832
Ref: library/unittest signal-handling13192953
Ref: 42a713192953
Ref: library/unittest unittest installHandler13194182
Ref: 42f713194182
Ref: library/unittest unittest registerResult13194426
Ref: 42f813194426
Ref: library/unittest unittest removeResult13194922
Ref: 42f913194922
Ref: library/unittest unittest removeHandler13195144
Ref: 137e13195144
Node: unittest mock — mock object library13195534
Ref: library/unittest mock doc13195711
Ref: 42fa13195711
Ref: library/unittest mock module-unittest mock13195711
Ref: 10713195711
Ref: library/unittest mock translation-repo13195711
Ref: 42fb13195711
Ref: library/unittest mock unittest-mock-mock-object-library13195711
Ref: 42fc13195711
Ref: unittest mock — mock object library-Footnote-113197348
Ref: unittest mock — mock object library-Footnote-213197421
Node: Quick Guide13197460
Ref: library/unittest mock quick-guide13197568
Ref: 42fd13197568
Node: The Mock Class13202976
Ref: library/unittest mock the-mock-class13203105
Ref: 430213203105
Ref: library/unittest mock unittest mock Mock13204117
Ref: a5813204117
Ref: library/unittest mock unittest mock Mock assert_called13207584
Ref: d1f13207584
Ref: library/unittest mock unittest mock Mock assert_called_once13207876
Ref: d2013207876
Ref: library/unittest mock unittest mock Mock assert_called_with13208514
Ref: 1bb213208514
Ref: library/unittest mock unittest mock Mock assert_called_once_with13208898
Ref: 430813208898
Ref: library/unittest mock unittest mock Mock assert_any_call13209579
Ref: 430913209579
Ref: library/unittest mock unittest mock Mock assert_has_calls13210228
Ref: 17ba13210228
Ref: library/unittest mock unittest mock Mock assert_not_called13211073
Ref: ec213211073
Ref: library/unittest mock unittest mock Mock reset_mock13211542
Ref: d2113211542
Ref: library/unittest mock unittest mock Mock mock_add_spec13213149
Ref: 430b13213149
Ref: library/unittest mock unittest mock Mock attach_mock13213474
Ref: 171813213474
Ref: library/unittest mock unittest mock Mock configure_mock13213767
Ref: 430713213767
Ref: library/unittest mock unittest mock Mock __dir__13214994
Ref: 430d13214994
Ref: library/unittest mock unittest mock Mock _get_child_mock13215321
Ref: 430f13215321
Ref: library/unittest mock unittest mock Mock called13215721
Ref: 431013215721
Ref: library/unittest mock unittest mock Mock call_count13216021
Ref: 15ce13216021
Ref: library/unittest mock unittest mock Mock return_value13216352
Ref: 430613216352
Ref: library/unittest mock unittest mock Mock side_effect13217158
Ref: 42fe13217158
Ref: library/unittest mock unittest mock Mock call_args13219621
Ref: 1b1213219621
Ref: library/unittest mock unittest mock Mock call_args_list13221451
Ref: 431113221451
Ref: library/unittest mock unittest mock Mock method_calls13222494
Ref: 430c13222494
Ref: library/unittest mock unittest mock Mock mock_calls13223232
Ref: 430a13223232
Ref: library/unittest mock unittest mock Mock __class__13224770
Ref: 431313224770
Ref: library/unittest mock unittest mock NonCallableMock13225529
Ref: 430313225529
Ref: library/unittest mock unittest mock PropertyMock13228036
Ref: 431413228036
Ref: library/unittest mock unittest mock AsyncMock13229917
Ref: a5713229917
Ref: library/unittest mock unittest mock AsyncMock assert_awaited13232722
Ref: 431513232722
Ref: library/unittest mock unittest mock AsyncMock assert_awaited_once13233457
Ref: 431613233457
Ref: library/unittest mock unittest mock AsyncMock assert_awaited_with13234015
Ref: 431713234015
Ref: library/unittest mock unittest mock AsyncMock assert_awaited_once_with13234685
Ref: 431813234685
Ref: library/unittest mock unittest mock AsyncMock assert_any_await13235410
Ref: 431913235410
Ref: library/unittest mock unittest mock AsyncMock assert_has_awaits13236053
Ref: 431a13236053
Ref: library/unittest mock unittest mock AsyncMock assert_not_awaited13237148
Ref: 431b13237148
Ref: library/unittest mock unittest mock AsyncMock reset_mock13237323
Ref: 431c13237323
Ref: library/unittest mock unittest mock AsyncMock await_count13237554
Ref: 431d13237554
Ref: library/unittest mock unittest mock AsyncMock await_args13238000
Ref: 431e13238000
Ref: library/unittest mock unittest mock AsyncMock await_args_list13238619
Ref: 1b1113238619
Ref: library/unittest mock unittest mock ThreadingMock13239331
Ref: 431f13239331
Ref: library/unittest mock unittest mock ThreadingMock wait_until_called13240031
Ref: 432113240031
Ref: library/unittest mock unittest mock ThreadingMock wait_until_any_call_with13240584
Ref: 432213240584
Ref: library/unittest mock unittest mock ThreadingMock DEFAULT_TIMEOUT13241183
Ref: 432013241183
Ref: The Mock Class-Footnote-113241502
Node: Calling13241924
Ref: library/unittest mock calling13242010
Ref: 432313242010
Node: Deleting Attributes13245280
Ref: library/unittest mock deleting-attributes13245408
Ref: 432413245408
Ref: library/unittest mock id213245408
Ref: 432513245408
Node: Mock names and the name attribute13246185
Ref: library/unittest mock mock-names-and-the-name-attribute13246335
Ref: 432613246335
Node: Attaching Mocks as Attributes13246925
Ref: library/unittest mock attaching-mocks-as-attributes13247047
Ref: 432713247047
Node: The patchers13248911
Ref: library/unittest mock the-patchers13249063
Ref: 432813249063
Node: patch13249678
Ref: library/unittest mock patch13249753
Ref: 432913249753
Ref: library/unittest mock unittest mock patch13249900
Ref: ec613249900
Node: patch object13258789
Ref: library/unittest mock patch-object13258883
Ref: 432b13258883
Ref: library/unittest mock unittest mock patch object13258928
Ref: 169e13258928
Node: patch dict13260376
Ref: library/unittest mock patch-dict13260479
Ref: 432c13260479
Ref: library/unittest mock unittest mock patch dict13260522
Ref: 1b8313260522
Node: patch multiple13264641
Ref: library/unittest mock patch-multiple13264760
Ref: 432e13264760
Ref: library/unittest mock unittest mock patch multiple13264811
Ref: 432f13264811
Node: patch methods start and stop13267478
Ref: library/unittest mock patch-methods-start-and-stop13267601
Ref: 433013267601
Ref: library/unittest mock start-and-stop13267601
Ref: 433113267601
Ref: library/unittest mock unittest mock patch stopall13270344
Ref: 433213270344
Node: patch builtins13270453
Ref: library/unittest mock id413270573
Ref: 433313270573
Ref: library/unittest mock patch-builtins13270573
Ref: 433413270573
Node: TEST_PREFIX13270894
Ref: library/unittest mock id513271010
Ref: 433513271010
Ref: library/unittest mock test-prefix13271010
Ref: 432d13271010
Node: Nesting Patch Decorators13271893
Ref: library/unittest mock nesting-patch-decorators13272009
Ref: 433613272009
Node: Where to patch13272926
Ref: library/unittest mock id613273069
Ref: 432a13273069
Ref: library/unittest mock where-to-patch13273069
Ref: 42ff13273069
Node: Patching Descriptors and Proxy Objects13274829
Ref: library/unittest mock patching-descriptors-and-proxy-objects13274939
Ref: 433713274939
Ref: Patching Descriptors and Proxy Objects-Footnote-113275380
Node: MagicMock and magic method support13275505
Ref: library/unittest mock magicmock-and-magic-method-support13275650
Ref: 433813275650
Node: Mocking Magic Methods13275792
Ref: library/unittest mock magic-methods13275903
Ref: 430013275903
Ref: library/unittest mock mocking-magic-methods13275903
Ref: 433913275903
Ref: Mocking Magic Methods-Footnote-113279793
Ref: Mocking Magic Methods-Footnote-213280032
Node: Magic Mock13280153
Ref: library/unittest mock magic-mock13280264
Ref: 433b13280264
Ref: library/unittest mock unittest mock MagicMock13280408
Ref: ec313280408
Ref: library/unittest mock unittest mock NonCallableMagicMock13280892
Ref: 430413280892
Node: Helpers13284233
Ref: library/unittest mock helpers13284423
Ref: 433c13284423
Node: sentinel13284596
Ref: library/unittest mock sentinel13284664
Ref: 433d13284664
Ref: library/unittest mock unittest mock sentinel13284703
Ref: bbe13284703
Node: DEFAULT13285864
Ref: library/unittest mock default13285945
Ref: 433e13285945
Ref: library/unittest mock unittest mock DEFAULT13285982
Ref: 430513285982
Node: call13286228
Ref: library/unittest mock call13286316
Ref: 433f13286316
Ref: library/unittest mock unittest mock call13286347
Ref: 1b5e13286347
Ref: library/unittest mock unittest mock call call_list13286869
Ref: 434013286869
Ref: library/unittest mock calls-as-tuples13287814
Ref: 431213287814
Node: create_autospec13289440
Ref: library/unittest mock create-autospec13289524
Ref: 434113289524
Ref: library/unittest mock unittest mock create_autospec13289577
Ref: 171213289577
Node: ANY13290870
Ref: library/unittest mock any13290960
Ref: 434213290960
Ref: library/unittest mock unittest mock ANY13290989
Ref: 1b5c13290989
Node: FILTER_DIR13292151
Ref: library/unittest mock filter-dir13292235
Ref: 434313292235
Ref: library/unittest mock unittest mock FILTER_DIR13292278
Ref: 430e13292278
Node: mock_open13294289
Ref: library/unittest mock mock-open13294382
Ref: 434413294382
Ref: library/unittest mock unittest mock mock_open13294423
Ref: 102213294423
Ref: mock_open-Footnote-113297260
Node: Autospeccing13297285
Ref: library/unittest mock auto-speccing13297381
Ref: 430113297381
Ref: library/unittest mock autospeccing13297381
Ref: 434513297381
Ref: Autospeccing-Footnote-113306086
Node: Sealing mocks13306327
Ref: library/unittest mock sealing-mocks13306405
Ref: 434613306405
Ref: library/unittest mock unittest mock seal13306454
Ref: bbf13306454
Node: Order of precedence of side_effect return_value and wraps13307268
Ref: library/unittest mock order-of-precedence-of-side-effect-return-value-and-wraps13307415
Ref: 434713307415
Node: unittest mock — getting started13311492
Ref: library/unittest mock-examples doc13311678
Ref: 434813311678
Ref: library/unittest mock-examples translation-repo13311678
Ref: 434913311678
Ref: library/unittest mock-examples unittest-mock-getting-started13311678
Ref: 434a13311678
Ref: library/unittest mock-examples getting-started13311790
Ref: 434b13311790
Node: Using Mock13311857
Ref: library/unittest mock-examples using-mock13311962
Ref: 434c13311962
Node: Mock patching methods13312427
Ref: library/unittest mock-examples mock-patching-methods13312538
Ref: 434d13312538
Node: Mock for method calls on an object13314088
Ref: library/unittest mock-examples mock-for-method-calls-on-an-object13314223
Ref: 434e13314223
Node: Mocking classes13315324
Ref: library/unittest mock-examples mocking-classes13315455
Ref: 434f13315455
Node: Naming your mocks13316452
Ref: library/unittest mock-examples naming-your-mocks13316567
Ref: 435013316567
Node: Tracking all calls13316999
Ref: library/unittest mock-examples tracking-all-calls13317135
Ref: 435113317135
Node: Setting return values and attributes13318542
Ref: library/unittest mock-examples setting-return-values-and-attributes13318690
Ref: 435213318690
Node: Raising exceptions with mocks13320201
Ref: library/unittest mock-examples raising-exceptions-with-mocks13320366
Ref: 435313320366
Node: Side effect functions and iterables13320746
Ref: library/unittest mock-examples side-effect-functions-and-iterables13320905
Ref: 435413320905
Node: Mocking asynchronous iterators13321945
Ref: library/unittest mock-examples mocking-asynchronous-iterators13322111
Ref: 435513322111
Node: Mocking asynchronous context manager13322684
Ref: library/unittest mock-examples mocking-asynchronous-context-manager13322854
Ref: 435613322854
Node: Creating a mock from an existing object13323755
Ref: library/unittest mock-examples creating-a-mock-from-an-existing-object13323939
Ref: 435713323939
Node: Using side_effect to return per file content13325785
Ref: library/unittest mock-examples using-side-effect-to-return-per-file-content13325924
Ref: 435813325924
Node: Patch decorators13326775
Ref: library/unittest mock-examples patch-decorators13326905
Ref: 435913326905
Node: Further examples13332178
Ref: library/unittest mock-examples further-examples13332289
Ref: 435a13332289
Ref: library/unittest mock-examples id113332289
Ref: 435b13332289
Node: Mocking chained calls13332917
Ref: library/unittest mock-examples mocking-chained-calls13333015
Ref: 435c13333015
Node: Partial mocking13336130
Ref: library/unittest mock-examples partial-mocking13336263
Ref: 435d13336263
Ref: Partial mocking-Footnote-113338259
Node: Mocking a generator method13338360
Ref: library/unittest mock-examples mocking-a-generator-method13338516
Ref: 435e13338516
Ref: Mocking a generator method-Footnote-113339650
Node: Applying the same patch to every test method13339970
Ref: library/unittest mock-examples applying-the-same-patch-to-every-test-method13340134
Ref: 435f13340134
Node: Mocking unbound methods13342432
Ref: library/unittest mock-examples mocking-unbound-methods13342603
Ref: 436013342603
Node: Checking multiple calls with mock13344373
Ref: library/unittest mock-examples checking-multiple-calls-with-mock13344529
Ref: 436113344529
Node: Coping with mutable arguments13346145
Ref: library/unittest mock-examples coping-with-mutable-arguments13346293
Ref: 436213346293
Node: Nesting patches13350477
Ref: library/unittest mock-examples nesting-patches13350627
Ref: 436313350627
Node: Mocking a dictionary with MagicMock13352434
Ref: library/unittest mock-examples mocking-a-dictionary-with-magicmock13352591
Ref: 436413352591
Node: Mock subclasses and their attributes13355238
Ref: library/unittest mock-examples mock-subclasses-and-their-attributes13355411
Ref: 436513355411
Ref: Mock subclasses and their attributes-Footnote-113357547
Ref: Mock subclasses and their attributes-Footnote-213357717
Ref: Mock subclasses and their attributes-Footnote-313357775
Node: Mocking imports with patch dict13357856
Ref: library/unittest mock-examples mocking-imports-with-patch-dict13358050
Ref: 436613358050
Node: Tracking order of calls and less verbose call assertions13360698
Ref: library/unittest mock-examples tracking-order-of-calls-and-less-verbose-call-assertions13360886
Ref: 436713360886
Node: More complex argument matching13364225
Ref: library/unittest mock-examples more-complex-argument-matching13364373
Ref: 436813364373
Ref: More complex argument matching-Footnote-113367445
Ref: More complex argument matching-Footnote-213367488
Node: test — Regression tests package for Python13367610
Ref: library/test doc13367811
Ref: 436913367811
Ref: library/test module-test13367811
Ref: e213367811
Ref: library/test test-regression-tests-package-for-python13367811
Ref: 436a13367811
Ref: library/test translation-repo13367811
Ref: 436b13367811
Node: Writing Unit Tests for the test package13369216
Ref: library/test writing-tests13369391
Ref: 436c13369391
Ref: library/test writing-unit-tests-for-the-test-package13369391
Ref: 436d13369391
Node: Running tests using the command-line interface13373959
Ref: library/test module-test regrtest13374134
Ref: e313374134
Ref: library/test regrtest13374134
Ref: 104413374134
Ref: library/test running-tests-using-the-command-line-interface13374134
Ref: 436e13374134
Node: test support — Utilities for the Python test suite13376046
Ref: library/test module-test support13376271
Ref: e413376271
Ref: library/test test-support-utilities-for-the-python-test-suite13376271
Ref: 436f13376271
Ref: library/test test support TestFailed13376767
Ref: 437013376767
Ref: library/test test support ResourceDenied13376987
Ref: 437113376987
Ref: library/test test support verbose13377276
Ref: 437313377276
Ref: library/test test support is_jython13377496
Ref: 437413377496
Ref: library/test test support is_android13377585
Ref: 437513377585
Ref: library/test test support unix_shell13377663
Ref: 437613377663
Ref: library/test test support LOOPBACK_TIMEOUT13377760
Ref: 1b4413377760
Ref: library/test test support INTERNET_TIMEOUT13378353
Ref: 1b4513378353
Ref: library/test test support SHORT_TIMEOUT13378842
Ref: 1a0913378842
Ref: library/test test support LONG_TIMEOUT13379227
Ref: 1b4613379227
Ref: library/test test support PGO13379736
Ref: 437813379736
Ref: library/test test support PIPE_MAX_SIZE13379834
Ref: 437913379834
Ref: library/test test support Py_DEBUG13379982
Ref: 437a13379982
Ref: library/test test support SOCK_MAX_SIZE13380187
Ref: 437c13380187
Ref: library/test test support TEST_SUPPORT_DIR13380337
Ref: 437d13380337
Ref: library/test test support TEST_HOME_DIR13380449
Ref: 437e13380449
Ref: library/test test support TEST_DATA_DIR13380546
Ref: 437f13380546
Ref: library/test test support MAX_Py_ssize_t13380647
Ref: 438013380647
Ref: library/test test support max_memuse13380746
Ref: 438113380746
Ref: library/test test support real_max_memuse13380909
Ref: 438313380909
Ref: library/test test support MISSING_C_DOCSTRINGS13381081
Ref: 438413381081
Ref: library/test test support HAVE_DOCSTRINGS13381368
Ref: 438513381368
Ref: library/test test support TEST_HTTP_URL13381643
Ref: 438613381643
Ref: library/test test support ALWAYS_EQ13381752
Ref: 438713381752
Ref: library/test test support NEVER_EQ13381868
Ref: 438813381868
Ref: library/test test support LARGEST13382020
Ref: 438913382020
Ref: library/test test support SMALLEST13382154
Ref: 438a13382154
Ref: library/test test support busy_retry13382350
Ref: 438b13382350
Ref: library/test test support sleeping_retry13382992
Ref: 438c13382992
Ref: library/test test support is_resource_enabled13383876
Ref: 438d13383876
Ref: library/test test support get_resource_value13384108
Ref: 438e13384108
Ref: library/test test support python_is_optimized13384319
Ref: 438f13384319
Ref: library/test test support with_pymalloc13384447
Ref: 439013384447
Ref: library/test test support requires13384536
Ref: 437213384536
Ref: library/test test support sortdict13384900
Ref: 439113384900
Ref: library/test test support findfile13384992
Ref: 439213384992
Ref: library/test test support get_pagesize13385364
Ref: 439313385364
Ref: library/test test support setswitchinterval13385472
Ref: 439413385472
Ref: library/test test support check_impl_detail13385698
Ref: 439513385698
Ref: library/test test support set_memlimit13386216
Ref: 438213386216
Ref: library/test test support record_original_stdout13386374
Ref: 439613386374
Ref: library/test test support get_original_stdout13386540
Ref: 439713386540
Ref: library/test test support args_from_interpreter_flags13386713
Ref: 439813386713
Ref: library/test test support optim_args_from_interpreter_flags13386902
Ref: 439913386902
Ref: library/test test support captured_stdin13387084
Ref: 439a13387084
Ref: library/test test support captured_stdout13387129
Ref: 439b13387129
Ref: library/test test support captured_stderr13387175
Ref: 1b8613387175
Ref: library/test test support disable_faulthandler13387900
Ref: 439c13387900
Ref: library/test test support gc_collect13388024
Ref: 439d13388024
Ref: library/test test support disable_gc13388360
Ref: 439e13388360
Ref: library/test test support swap_attr13388541
Ref: 439f13388541
Ref: library/test test support swap_item13389127
Ref: 43a013389127
Ref: library/test test support flush_std_streams13389711
Ref: 43a113389711
Ref: library/test test support print_warning13389987
Ref: 43a213389987
Ref: library/test test support wait_process13390261
Ref: 1b0613390261
Ref: library/test test support calcobjsize13390780
Ref: 43a413390780
Ref: library/test test support calcvobjsize13391013
Ref: 43a513391013
Ref: library/test test support checksizeof13391251
Ref: 43a713391251
Ref: library/test test support anticipate_failure13391422
Ref: 43a813391422
Ref: library/test test support system_must_validate_cert13391684
Ref: 43a913391684
Ref: library/test test support run_with_locale13391837
Ref: 43aa13391837
Ref: library/test test support run_with_tz13392197
Ref: 43ab13392197
Ref: library/test test support requires_freebsd_version13392359
Ref: 43ac13392359
Ref: library/test test support requires_linux_version13392573
Ref: 43ad13392573
Ref: library/test test support requires_mac_version13392782
Ref: 43ae13392782
Ref: library/test test support requires_gil_enabled13392988
Ref: 43af13392988
Ref: library/test test support requires_IEEE_75413393164
Ref: 43b013393164
Ref: library/test test support requires_zlib13393273
Ref: 43b113393273
Ref: library/test test support requires_gzip13393388
Ref: 43b213393388
Ref: library/test test support requires_bz213393502
Ref: 43b313393502
Ref: library/test test support requires_lzma13393614
Ref: 43b413393614
Ref: library/test test support requires_resource13393728
Ref: 43b513393728
Ref: library/test test support requires_docstrings13393853
Ref: 43b613393853
Ref: library/test test support requires_limited_api13393976
Ref: 43b713393976
Ref: library/test test support cpython_only13394116
Ref: 43b813394116
Ref: library/test test support impl_detail13394212
Ref: 43b913394212
Ref: library/test test support no_tracing13394442
Ref: 43ba13394442
Ref: library/test test support refcount_test13394565
Ref: 43bb13394565
Ref: library/test test support bigmemtest13394869
Ref: 43bc13394869
Ref: library/test test support bigaddrspacetest13395616
Ref: 43bd13395616
Ref: library/test test support check_syntax_error13395717
Ref: 43be13395717
Ref: library/test test support open_urlresource13396271
Ref: 43bf13396271
Ref: library/test test support reap_children13396400
Ref: 43c013396400
Ref: library/test test support get_attribute13396674
Ref: 43c113396674
Ref: library/test test support catch_unraisable_exception13396837
Ref: 1b6813396837
Ref: library/test test support load_package_tests13397725
Ref: 43c213397725
Ref: library/test test support detect_api_mismatch13398355
Ref: 43c313398355
Ref: library/test test support patch13398826
Ref: 43c413398826
Ref: library/test test support run_in_subinterp13399162
Ref: 43c513399162
Ref: library/test test support check_free_after_iterating13399331
Ref: 43c613399331
Ref: library/test test support missing_compiler_executable13399488
Ref: 43c713399488
Ref: library/test test support check__all__13399810
Ref: 1ada13399810
Ref: library/test test support skip_if_broken_multiprocessing_synchronize13401630
Ref: 1adb13401630
Ref: library/test test support check_disallow_instantiation13401923
Ref: 43c813401923
Ref: library/test test support adjust_int_max_str_digits13402131
Ref: 43c913402131
Ref: library/test test support SuppressCrashReport13402597
Ref: 43ca13402597
Ref: library/test test support SaveSignals13403100
Ref: 43cc13403100
Ref: library/test test support SaveSignals save13403231
Ref: 43cd13403231
Ref: library/test test support SaveSignals restore13403377
Ref: 43ce13403377
Ref: library/test test support Matcher13403516
Ref: 43cf13403516
Ref: library/test test support Matcher matches13403549
Ref: 43d013403549
Ref: library/test test support Matcher match_value13403662
Ref: 43d113403662
Ref: test support — Utilities for the Python test suite-Footnote-113403837
Node: test support socket_helper — Utilities for socket tests13403917
Ref: library/test module-test support socket_helper13404169
Ref: e913404169
Ref: library/test test-support-socket-helper-utilities-for-socket-tests13404169
Ref: 43d213404169
Ref: library/test test support socket_helper IPV6_ENABLED13404411
Ref: 43d313404411
Ref: library/test test support socket_helper find_unused_port13404542
Ref: 43d413404542
Ref: library/test test support socket_helper bind_port13405851
Ref: 43d513405851
Ref: library/test test support socket_helper bind_unix_socket13406796
Ref: 43d613406796
Ref: library/test test support socket_helper skip_unless_bind_unix_socket13406980
Ref: 43d713406980
Ref: library/test test support socket_helper transient_internet13407150
Ref: 437713407150
Node: test support script_helper — Utilities for the Python execution tests13407423
Ref: library/test module-test support script_helper13407709
Ref: e813407709
Ref: library/test test-support-script-helper-utilities-for-the-python-execution-tests13407709
Ref: 43d813407709
Ref: library/test test support script_helper interpreter_requires_environment13407977
Ref: 43d913407977
Ref: library/test test support script_helper run_python_until_end13408953
Ref: 43da13408953
Ref: library/test test support script_helper assert_python_ok13409331
Ref: 43db13409331
Ref: library/test test support script_helper assert_python_failure13409964
Ref: 43dc13409964
Ref: library/test test support script_helper spawn_python13410398
Ref: 43dd13410398
Ref: library/test test support script_helper kill_python13410711
Ref: 43de13410711
Ref: library/test test support script_helper make_script13410867
Ref: 43df13410867
Ref: library/test test support script_helper make_zip_script13411176
Ref: 43e013411176
Ref: library/test test support script_helper make_pkg13411545
Ref: 43e113411545
Ref: library/test test support script_helper make_zip_pkg13411748
Ref: 43e213411748
Node: test support bytecode_helper — Support tools for testing correct bytecode generation13412278
Ref: library/test module-test support bytecode_helper13412570
Ref: e513412570
Ref: library/test test-support-bytecode-helper-support-tools-for-testing-correct-bytecode-generation13412570
Ref: 43e313412570
Ref: library/test test support bytecode_helper BytecodeTestCase13412943
Ref: 43e413412943
Ref: library/test test support bytecode_helper BytecodeTestCase get_disassembly_as_string13413102
Ref: 43e513413102
Ref: library/test test support bytecode_helper BytecodeTestCase assertInBytecode13413211
Ref: 43e613413211
Ref: library/test test support bytecode_helper BytecodeTestCase assertNotInBytecode13413391
Ref: 43e713413391
Node: test support threading_helper — Utilities for threading tests13413546
Ref: library/test module-test support threading_helper13413816
Ref: ea13413816
Ref: library/test test-support-threading-helper-utilities-for-threading-tests13413816
Ref: 43e813413816
Ref: library/test test support threading_helper join_thread13414077
Ref: 43e913414077
Ref: library/test test support threading_helper reap_threads13414299
Ref: 43ea13414299
Ref: library/test test support threading_helper start_threads13414440
Ref: 43eb13414440
Ref: library/test test support threading_helper threading_cleanup13414848
Ref: 43ec13414848
Ref: library/test test support threading_helper threading_setup13415086
Ref: 43ed13415086
Ref: library/test test support threading_helper wait_threads_exit13415214
Ref: 43ee13415214
Ref: library/test test support threading_helper catch_threading_exception13415397
Ref: 43ef13415397
Node: test support os_helper — Utilities for os tests13416358
Ref: library/test module-test support os_helper13416599
Ref: e713416599
Ref: library/test test-support-os-helper-utilities-for-os-tests13416599
Ref: 43f013416599
Ref: library/test test support os_helper FS_NONASCII13416818
Ref: 43f113416818
Ref: library/test test support os_helper SAVEDCWD13416931
Ref: 43f213416931
Ref: library/test test support os_helper TESTFN13417012
Ref: 43f313417012
Ref: library/test test support os_helper TESTFN_NONASCII13417212
Ref: 43f413417212
Ref: library/test test support os_helper TESTFN_UNENCODABLE13417597
Ref: 43f513417597
Ref: library/test test support os_helper TESTFN_UNDECODABLE13417847
Ref: 43f613417847
Ref: library/test test support os_helper TESTFN_UNICODE13418099
Ref: 43f713418099
Ref: library/test test support os_helper EnvironmentVarGuard13418200
Ref: 143013418200
Ref: library/test test support os_helper FakePath13418668
Ref: 43f813418668
Ref: library/test test support os_helper EnvironmentVarGuard set13418930
Ref: 43f913418930
Ref: library/test test support os_helper EnvironmentVarGuard unset13419077
Ref: 43fa13419077
Ref: library/test test support os_helper can_symlink13419188
Ref: 43fb13419188
Ref: library/test test support os_helper can_xattr13419323
Ref: 43fc13419323
Ref: library/test test support os_helper change_cwd13419447
Ref: 43fd13419447
Ref: library/test test support os_helper create_empty_file13419816
Ref: 43fe13419816
Ref: library/test test support os_helper fd_count13419968
Ref: 43ff13419968
Ref: library/test test support os_helper fs_is_case_insensitive13420067
Ref: 440013420067
Ref: library/test test support os_helper make_bad_fd13420225
Ref: 440113420225
Ref: library/test test support os_helper rmdir13420394
Ref: 440213420394
Ref: library/test test support os_helper rmtree13420702
Ref: 440313420702
Ref: library/test test support os_helper skip_unless_symlink13421045
Ref: 440413421045
Ref: library/test test support os_helper skip_unless_xattr13421186
Ref: 440513421186
Ref: library/test test support os_helper temp_cwd13421311
Ref: 440613421311
Ref: library/test test support os_helper temp_dir13421968
Ref: 440713421968
Ref: library/test test support os_helper temp_umask13422420
Ref: 440813422420
Ref: library/test test support os_helper unlink13422542
Ref: 440913422542
Node: test support import_helper — Utilities for import tests13422787
Ref: library/test module-test support import_helper13423026
Ref: e613423026
Ref: library/test test-support-import-helper-utilities-for-import-tests13423026
Ref: 440a13423026
Ref: library/test test support import_helper forget13423269
Ref: 440b13423269
Ref: library/test test support import_helper import_fresh_module13423454
Ref: 1a0813423454
Ref: library/test test support import_helper import_module13425071
Ref: 440c13425071
Ref: library/test test support import_helper modules_setup13425693
Ref: 440d13425693
Ref: library/test test support import_helper modules_cleanup13425800
Ref: 440e13425800
Ref: library/test test support import_helper unload13425978
Ref: 440f13425978
Ref: library/test test support import_helper make_legacy_pyc13426078
Ref: 441013426078
Ref: library/test test support import_helper CleanImport13426427
Ref: 441113426427
Ref: library/test test support import_helper DirsOnSysPath13426817
Ref: 441213426817
Ref: test support import_helper — Utilities for import tests-Footnote-113427368
Ref: test support import_helper — Utilities for import tests-Footnote-213427410
Node: test support warnings_helper — Utilities for warnings tests13427452
Ref: library/test module-test support warnings_helper13427633
Ref: eb13427633
Ref: library/test test-support-warnings-helper-utilities-for-warnings-tests13427633
Ref: 441313427633
Ref: library/test test support warnings_helper ignore_warnings13427888
Ref: 441413427888
Ref: library/test test support warnings_helper check_no_resource_warning13428401
Ref: 441513428401
Ref: library/test test support warnings_helper check_syntax_warning13428685
Ref: 441613428685
Ref: library/test test support warnings_helper check_warnings13429488
Ref: 441713429488
Ref: library/test test support warnings_helper WarningsRecorder13432546
Ref: 441813432546
Node: Debugging and Profiling13432737
Ref: library/debug doc13432894
Ref: 441913432894
Ref: library/debug debugging-and-profiling13432894
Ref: 441a13432894
Ref: library/debug translation-repo13432894
Ref: 441b13432894
Ref: library/audit_events audit-events13433354
Ref: 19b713433354
Node: Audit events table13433684
Ref: library/audit_events doc13433797
Ref: 441c13433797
Ref: library/audit_events audit-events-table13433797
Ref: 441d13433797
Ref: Audit events table-Footnote-113492659
Node: bdb — Debugger framework13492701
Ref: library/bdb doc13492865
Ref: 443c13492865
Ref: library/bdb bdb-debugger-framework13492865
Ref: 443d13492865
Ref: library/bdb module-bdb13492865
Ref: f13492865
Ref: library/bdb translation-repo13492865
Ref: 443e13492865
Ref: library/bdb bdb BdbQuit13493196
Ref: 443f13493196
Ref: library/bdb bdb Breakpoint13493357
Ref: 444013493357
Ref: library/bdb bdb Breakpoint deleteMe13494292
Ref: 444713494292
Ref: library/bdb bdb Breakpoint enable13494508
Ref: 444813494508
Ref: library/bdb bdb Breakpoint disable13494579
Ref: 444913494579
Ref: library/bdb bdb Breakpoint bpformat13494652
Ref: 444a13494652
Ref: library/bdb bdb Breakpoint bpprint13495049
Ref: 444b13495049
Ref: library/bdb bdb Breakpoint file13495278
Ref: 444313495278
Ref: library/bdb bdb Breakpoint line13495350
Ref: 444c13495350
Ref: library/bdb bdb Breakpoint temporary13495448
Ref: 444d13495448
Ref: library/bdb bdb Breakpoint cond13495553
Ref: 444613495553
Ref: library/bdb bdb Breakpoint funcname13495651
Ref: 444413495651
Ref: library/bdb bdb Breakpoint enabled13495791
Ref: 444e13495791
Ref: library/bdb bdb Breakpoint bpbynumber13495874
Ref: 444113495874
Ref: library/bdb bdb Breakpoint bplist13495976
Ref: 444213495976
Ref: library/bdb bdb Breakpoint ignore13496123
Ref: 444f13496123
Ref: library/bdb bdb Breakpoint hits13496208
Ref: 444513496208
Ref: library/bdb bdb Bdb13496307
Ref: 134b13496307
Ref: library/bdb bdb Bdb canonic13497086
Ref: 445013497086
Ref: library/bdb bdb Bdb reset13497465
Ref: 445113497465
Ref: library/bdb bdb Bdb trace_dispatch13497657
Ref: 445313497657
Ref: library/bdb bdb Bdb dispatch_line13499076
Ref: 445413499076
Ref: library/bdb bdb Bdb dispatch_call13499546
Ref: 445613499546
Ref: library/bdb bdb Bdb dispatch_return13500023
Ref: 445813500023
Ref: library/bdb bdb Bdb dispatch_exception13500508
Ref: 445a13500508
Ref: library/bdb bdb Bdb is_skipped_module13501160
Ref: 445c13501160
Ref: library/bdb bdb Bdb stop_here13501282
Ref: 445d13501282
Ref: library/bdb bdb Bdb break_here13501410
Ref: 445e13501410
Ref: library/bdb bdb Bdb break_anywhere13501718
Ref: 446013501718
Ref: library/bdb bdb Bdb user_call13501937
Ref: 445713501937
Ref: library/bdb bdb Bdb user_line13502238
Ref: 445513502238
Ref: library/bdb bdb Bdb user_return13502432
Ref: 445913502432
Ref: library/bdb bdb Bdb user_exception13502598
Ref: 445b13502598
Ref: library/bdb bdb Bdb do_clear13502766
Ref: 446113502766
Ref: library/bdb bdb Bdb set_step13503051
Ref: 446213503051
Ref: library/bdb bdb Bdb set_next13503121
Ref: 446313503121
Ref: library/bdb bdb Bdb set_return13503218
Ref: 446413503218
Ref: library/bdb bdb Bdb set_until13503308
Ref: 446513503308
Ref: library/bdb bdb Bdb set_trace13503493
Ref: 446613503493
Ref: library/bdb bdb Bdb set_continue13503823
Ref: 446813503823
Ref: library/bdb bdb Bdb set_quit13503996
Ref: 445213503996
Ref: library/bdb bdb Bdb set_break13504414
Ref: 446913504414
Ref: library/bdb bdb Bdb clear_break13504779
Ref: 446a13504779
Ref: library/bdb bdb Bdb clear_bpbynumber13504944
Ref: 446b13504944
Ref: library/bdb bdb Bdb clear_all_file_breaks13505173
Ref: 446c13505173
Ref: library/bdb bdb Bdb clear_all_breaks13505327
Ref: 446d13505327
Ref: library/bdb bdb Bdb get_bpbynumber13505463
Ref: 446e13505463
Ref: library/bdb bdb Bdb get_break13505814
Ref: 446f13505814
Ref: library/bdb bdb Bdb get_breaks13505953
Ref: 447013505953
Ref: library/bdb bdb Bdb get_file_breaks13506107
Ref: 447113506107
Ref: library/bdb bdb Bdb get_all_breaks13506245
Ref: 447213506245
Ref: library/bdb bdb Bdb get_stack13506451
Ref: 447313506451
Ref: library/bdb bdb Bdb format_stack_entry13506742
Ref: 447413506742
Ref: library/bdb bdb Bdb run13507325
Ref: 447513507325
Ref: library/bdb bdb Bdb runeval13507555
Ref: 447613507555
Ref: library/bdb bdb Bdb runctx13507783
Ref: 447713507783
Ref: library/bdb bdb Bdb runcall13507919
Ref: a8d13507919
Ref: library/bdb bdb checkfuncname13508088
Ref: 447813508088
Ref: library/bdb bdb effective13508541
Ref: 445f13508541
Ref: library/bdb bdb set_trace13509295
Ref: 446713509295
Ref: bdb — Debugger framework-Footnote-113509446
Node: faulthandler — Dump the Python traceback13509509
Ref: library/faulthandler doc13509682
Ref: 447913509682
Ref: library/faulthandler faulthandler-dump-the-python-traceback13509682
Ref: 447a13509682
Ref: library/faulthandler module-faulthandler13509682
Ref: 5813509682
Ref: library/faulthandler translation-repo13509682
Ref: 447b13509682
Node: Dumping the traceback13512081
Ref: library/faulthandler dumping-the-traceback13512209
Ref: 447c13512209
Ref: library/faulthandler faulthandler dump_traceback13512272
Ref: e3013512272
Node: Fault handler state13512699
Ref: library/faulthandler fault-handler-state13512874
Ref: 447d13512874
Ref: library/faulthandler faulthandler enable13512933
Ref: cc413512933
Ref: library/faulthandler faulthandler disable13513789
Ref: 447f13513789
Ref: library/faulthandler faulthandler is_enabled13513930
Ref: 448013513930
Node: Dumping the tracebacks after a timeout13514017
Ref: library/faulthandler dumping-the-tracebacks-after-a-timeout13514209
Ref: 448113514209
Ref: library/faulthandler faulthandler dump_traceback_later13514306
Ref: e3113514306
Ref: library/faulthandler faulthandler cancel_dump_traceback_later13515338
Ref: 448213515338
Node: Dumping the traceback on a user signal13515462
Ref: library/faulthandler dumping-the-traceback-on-a-user-signal13515662
Ref: 448313515662
Ref: library/faulthandler faulthandler register13515759
Ref: e2f13515759
Ref: library/faulthandler faulthandler unregister13516390
Ref: 448413516390
Node: Issue with file descriptors13516665
Ref: library/faulthandler faulthandler-fd13516838
Ref: 447e13516838
Ref: library/faulthandler issue-with-file-descriptors13516838
Ref: 448513516838
Node: Example<13>13517306
Ref: library/faulthandler example13517432
Ref: 448613517432
Node: pdb — The Python Debugger13517976
Ref: library/pdb doc13518143
Ref: 448713518143
Ref: library/pdb debugger13518143
Ref: 448813518143
Ref: library/pdb module-pdb13518143
Ref: a513518143
Ref: library/pdb pdb-the-python-debugger13518143
Ref: 448913518143
Ref: library/pdb translation-repo13518143
Ref: 448a13518143
Ref: pdb — The Python Debugger-Footnote-113520353
Node: Command-line interface<6>13520416
Ref: library/pdb command-line-interface13520531
Ref: 448c13520531
Ref: library/pdb pdb-cli13520531
Ref: 448d13520531
Ref: library/pdb cmdoption-pdb-c13521126
Ref: 448e13521126
Ref: library/pdb cmdoption-pdb-command13521126
Ref: 448f13521126
Ref: library/pdb cmdoption-pdb-m13521322
Ref: 449113521322
Ref: library/pdb pdb run13522481
Ref: 428e13522481
Ref: library/pdb pdb runeval13523173
Ref: 449413523173
Ref: library/pdb pdb runcall13523479
Ref: 449513523479
Ref: library/pdb pdb set_trace13523787
Ref: 23513523787
Ref: library/pdb pdb post_mortem13524347
Ref: 142813524347
Ref: library/pdb pdb pm13524690
Ref: 23713524690
Ref: library/pdb pdb Pdb13525027
Ref: 92b13525027
Ref: library/pdb pdb Pdb run13526428
Ref: 449613526428
Ref: library/pdb pdb Pdb runeval13526488
Ref: 449713526488
Ref: library/pdb pdb Pdb runcall13526553
Ref: 449813526553
Ref: library/pdb pdb Pdb set_trace13526604
Ref: 449913526604
Ref: Command-line interface<6>-Footnote-113526739
Ref: Command-line interface<6>-Footnote-213526781
Node: Debugger commands13526910
Ref: library/pdb debugger-commands13527025
Ref: 449013527025
Ref: library/pdb id213527025
Ref: 449a13527025
Ref: library/pdb pdbcommand-help13530525
Ref: 449d13530525
Ref: library/pdb pdbcommand-where13530913
Ref: 449e13530913
Ref: library/pdb pdbcommand-down13531113
Ref: 449f13531113
Ref: library/pdb pdbcommand-up13531252
Ref: 44a013531252
Ref: library/pdb pdbcommand-break13531388
Ref: 44a113531388
Ref: library/pdb pdbcommand-tbreak13532514
Ref: 44a213532514
Ref: library/pdb pdbcommand-clear13532725
Ref: 44a313532725
Ref: library/pdb pdbcommand-disable13533022
Ref: 44a413533022
Ref: library/pdb pdbcommand-enable13533345
Ref: 44a513533345
Ref: library/pdb pdbcommand-ignore13533433
Ref: 44a613533433
Ref: library/pdb pdbcommand-condition13533835
Ref: 44a713533835
Ref: library/pdb pdbcommand-commands13534128
Ref: 44a813534128
Ref: library/pdb pdbcommand-step13535763
Ref: 449213535763
Ref: library/pdb pdbcommand-next13535948
Ref: 449313535948
Ref: library/pdb pdbcommand-until13536327
Ref: 44ac13536327
Ref: library/pdb pdbcommand-return13536723
Ref: 44a913536723
Ref: library/pdb pdbcommand-continue13536810
Ref: 448b13536810
Ref: library/pdb pdbcommand-jump13536910
Ref: 44aa13536910
Ref: library/pdb pdbcommand-list13537340
Ref: 449b13537340
Ref: library/pdb pdbcommand-ll13538088
Ref: 44ad13538088
Ref: library/pdb pdbcommand-args13538268
Ref: 44ae13538268
Ref: library/pdb pdbcommand-p13538373
Ref: faf13538373
Ref: library/pdb pdbcommand-pp13538633
Ref: 44af13538633
Ref: library/pdb pdbcommand-whatis13538794
Ref: 44b013538794
Ref: library/pdb pdbcommand-source13538867
Ref: 44b113538867
Ref: library/pdb pdbcommand-display13538991
Ref: 44b213538991
Ref: library/pdb pdbcommand-undisplay13540444
Ref: 44b313540444
Ref: library/pdb pdbcommand-interact13540657
Ref: 44b413540657
Ref: library/pdb debugger-aliases13541560
Ref: 449c13541560
Ref: library/pdb pdbcommand-alias13541560
Ref: 44b513541560
Ref: library/pdb pdbcommand-unalias13542669
Ref: 44b613542669
Ref: library/pdb pdbcommand-013542740
Ref: 44b713542740
Ref: library/pdb pdbcommand-run13543227
Ref: 44b813543227
Ref: library/pdb pdbcommand-restart13543258
Ref: 44b913543258
Ref: library/pdb pdbcommand-quit13543593
Ref: 44ab13543593
Ref: library/pdb pdbcommand-debug13543687
Ref: 44ba13543687
Ref: library/pdb pdbcommand-retval13543875
Ref: 44bb13543875
Ref: library/pdb pdbcommand-exceptions13543973
Ref: 23813543973
Node: The Python Profilers13545300
Ref: library/profile doc13545481
Ref: 44bc13545481
Ref: library/profile profile13545481
Ref: 44bd13545481
Ref: library/profile the-python-profilers13545481
Ref: 44be13545481
Ref: library/profile translation-repo13545481
Ref: 44bf13545481
Ref: The Python Profilers-Footnote-113545925
Ref: The Python Profilers-Footnote-213545992
Node: Introduction to the profilers13546058
Ref: library/profile introduction-to-the-profilers13546176
Ref: 44c013546176
Ref: library/profile profiler-introduction13546176
Ref: 44c113546176
Node: Instant User’s Manual13547661
Ref: library/profile instant-user-s-manual13547825
Ref: 44c213547825
Ref: library/profile profile-instant13547825
Ref: 44c313547825
Ref: library/profile profile-cli13550705
Ref: 44c513550705
Ref: library/profile cmdoption-cProfile-o13550918
Ref: 44c613550918
Ref: library/profile cmdoption-cProfile-s13551013
Ref: 44c713551013
Ref: library/profile cmdoption-cProfile-m13551197
Ref: 44c913551197
Node: profile and cProfile Module Reference13554125
Ref: library/profile module-cProfile13554275
Ref: 2713554275
Ref: library/profile profile-and-cprofile-module-reference13554275
Ref: 44cc13554275
Ref: library/profile module-profile13554386
Ref: af13554386
Ref: library/profile profile run13554475
Ref: 44cd13554475
Ref: library/profile profile runctx13555103
Ref: 44ce13555103
Ref: library/profile profile Profile13555500
Ref: 9ee13555500
Ref: library/profile profile Profile enable13557055
Ref: 44cf13557055
Ref: library/profile profile Profile disable13557152
Ref: 44d013557152
Ref: library/profile profile Profile create_stats13557249
Ref: 44d113557249
Ref: library/profile profile Profile print_stats13557393
Ref: 44d213557393
Ref: library/profile profile Profile dump_stats13557874
Ref: 44d313557874
Ref: library/profile profile Profile run13557981
Ref: 44d413557981
Ref: library/profile profile Profile runctx13558059
Ref: 44d513558059
Ref: library/profile profile Profile runcall13558216
Ref: a8c13558216
Node: The Stats Class13558561
Ref: library/profile profile-stats13558720
Ref: 44d613558720
Ref: library/profile the-stats-class13558720
Ref: 44d713558720
Ref: library/profile module-pstats13558854
Ref: b013558854
Ref: library/profile pstats Stats13558854
Ref: 44c413558854
Ref: library/profile pstats Stats strip_dirs13560110
Ref: 44ca13560110
Ref: library/profile pstats Stats add13560924
Ref: 44d813560924
Ref: library/profile pstats Stats dump_stats13561410
Ref: 44d913561410
Ref: library/profile pstats Stats sort_stats13561784
Ref: 44c813561784
Ref: library/profile pstats Stats reverse_order13567136
Ref: 44da13567136
Ref: library/profile pstats Stats print_stats13567415
Ref: 44cb13567415
Ref: library/profile pstats Stats print_callers13568845
Ref: 44db13568845
Ref: library/profile pstats Stats print_callees13569953
Ref: 44dc13569953
Ref: library/profile pstats Stats get_stats_profile13570328
Ref: 44dd13570328
Node: What Is Deterministic Profiling?13570875
Ref: library/profile deterministic-profiling13571008
Ref: 44de13571008
Ref: library/profile what-is-deterministic-profiling13571008
Ref: 44df13571008
Node: Limitations13572806
Ref: library/profile limitations13572935
Ref: 44e013572935
Ref: library/profile profile-limitations13572935
Ref: 44e113572935
Node: Calibration13574813
Ref: library/profile calibration13574930
Ref: 44e213574930
Ref: library/profile profile-calibration13574930
Ref: 44e313574930
Node: Using a custom timer13576622
Ref: library/profile profile-timers13576719
Ref: 44e413576719
Ref: library/profile using-a-custom-timer13576719
Ref: 44e513576719
Node: timeit — Measure execution time of small code snippets13579170
Ref: library/timeit doc13579375
Ref: 44e613579375
Ref: library/timeit module-timeit13579375
Ref: ef13579375
Ref: library/timeit timeit-measure-execution-time-of-small-code-snippets13579375
Ref: 44e713579375
Ref: library/timeit translation-repo13579375
Ref: 44e813579375
Ref: timeit — Measure execution time of small code snippets-Footnote-113580160
Node: Basic Examples<2>13580226
Ref: library/timeit basic-examples13580361
Ref: 44eb13580361
Node: Python Interface13581646
Ref: library/timeit id113581815
Ref: 44ed13581815
Ref: library/timeit python-interface13581815
Ref: 44ea13581815
Ref: library/timeit timeit timeit13581936
Ref: eb213581936
Ref: library/timeit timeit repeat13582399
Ref: 44ee13582399
Ref: library/timeit timeit default_timer13582989
Ref: 44f013582989
Ref: library/timeit timeit Timer13583284
Ref: 151713583284
Ref: library/timeit timeit Timer timeit13584725
Ref: d1413584725
Ref: library/timeit timeit Timer autorange13585831
Ref: d1313585831
Ref: library/timeit timeit Timer repeat13586555
Ref: 44ef13586555
Ref: library/timeit timeit Timer print_exc13587821
Ref: 44f113587821
Node: Command-Line Interface<3>13588401
Ref: library/timeit command-line-interface13588565
Ref: 44f213588565
Ref: library/timeit timeit-command-line-interface13588565
Ref: 44e913588565
Ref: library/timeit cmdoption-timeit-n13588834
Ref: 44f313588834
Ref: library/timeit cmdoption-timeit-number13588834
Ref: 44f413588834
Ref: library/timeit cmdoption-timeit-r13588912
Ref: 44f513588912
Ref: library/timeit cmdoption-timeit-repeat13588912
Ref: 44f613588912
Ref: library/timeit cmdoption-timeit-s13588995
Ref: 44f713588995
Ref: library/timeit cmdoption-timeit-setup13588995
Ref: 44f813588995
Ref: library/timeit cmdoption-timeit-p13589091
Ref: 44f913589091
Ref: library/timeit cmdoption-timeit-process13589091
Ref: 44fa13589091
Ref: library/timeit cmdoption-timeit-u13589306
Ref: 44fb13589306
Ref: library/timeit cmdoption-timeit-unit13589306
Ref: 44fc13589306
Ref: library/timeit cmdoption-timeit-v13589469
Ref: 44fd13589469
Ref: library/timeit cmdoption-timeit-verbose13589469
Ref: 44fe13589469
Ref: library/timeit cmdoption-timeit-h13589561
Ref: 44ff13589561
Ref: library/timeit cmdoption-timeit-help13589561
Ref: 450013589561
Node: Examples<30>13590772
Ref: library/timeit examples13590911
Ref: 450113590911
Ref: library/timeit timeit-examples13590911
Ref: 44ec13590911
Node: trace — Trace or track Python statement execution13594540
Ref: library/trace doc13594765
Ref: 450213594765
Ref: library/trace module-trace13594765
Ref: fd13594765
Ref: library/trace trace-trace-or-track-python-statement-execution13594765
Ref: 450313594765
Ref: library/trace translation-repo13594765
Ref: 450413594765
Ref: trace — Trace or track Python statement execution-Footnote-113595526
Ref: trace — Trace or track Python statement execution-Footnote-213595591
Node: Command-Line Usage<3>13595632
Ref: library/trace command-line-usage13595772
Ref: 450513595772
Ref: library/trace trace-cli13595772
Ref: 450613595772
Ref: library/trace cmdoption-trace-help13596120
Ref: 450713596120
Ref: library/trace cmdoption-trace-version13596170
Ref: 450813596170
Node: Main options13596389
Ref: library/trace main-options13596477
Ref: 450913596477
Ref: library/trace cmdoption-trace-c13596833
Ref: 450c13596833
Ref: library/trace cmdoption-trace-count13596833
Ref: 450d13596833
Ref: library/trace cmdoption-trace-t13597086
Ref: 450b13597086
Ref: library/trace cmdoption-trace-trace13597086
Ref: 451113597086
Ref: library/trace cmdoption-trace-l13597153
Ref: 450a13597153
Ref: library/trace cmdoption-trace-listfuncs13597153
Ref: 451213597153
Ref: library/trace cmdoption-trace-r13597243
Ref: 451313597243
Ref: library/trace cmdoption-trace-report13597243
Ref: 451413597243
Ref: library/trace cmdoption-trace-T13597437
Ref: 451513597437
Ref: library/trace cmdoption-trace-trackcalls13597437
Ref: 451613597437
Node: Modifiers13597539
Ref: library/trace modifiers13597643
Ref: 451713597643
Ref: library/trace cmdoption-trace-f13597682
Ref: 450f13597682
Ref: library/trace cmdoption-trace-file13597682
Ref: 451813597682
Ref: library/trace cmdoption-trace-C13597839
Ref: 450e13597839
Ref: library/trace cmdoption-trace-coverdir13597839
Ref: 451913597839
Ref: library/trace cmdoption-trace-m13598029
Ref: 451a13598029
Ref: library/trace cmdoption-trace-missing13598029
Ref: 451b13598029
Ref: library/trace cmdoption-trace-s13598157
Ref: 451c13598157
Ref: library/trace cmdoption-trace-summary13598157
Ref: 451d13598157
Ref: library/trace cmdoption-trace-R13598307
Ref: 451013598307
Ref: library/trace cmdoption-trace-no-report13598307
Ref: 451e13598307
Ref: library/trace cmdoption-trace-g13598528
Ref: 451f13598528
Ref: library/trace cmdoption-trace-timing13598528
Ref: 452013598528
Node: Filters13598649
Ref: library/trace filters13598732
Ref: 452113598732
Ref: library/trace cmdoption-trace-ignore-module13598814
Ref: 452213598814
Ref: library/trace cmdoption-trace-ignore-dir13599003
Ref: 452313599003
Node: Programmatic Interface13599206
Ref: library/trace programmatic-interface13599346
Ref: 452413599346
Ref: library/trace trace-api13599346
Ref: 452513599346
Ref: library/trace trace Trace13599411
Ref: 452613599411
Ref: library/trace trace Trace run13600322
Ref: 452713600322
Ref: library/trace trace Trace runctx13600564
Ref: 452813600564
Ref: library/trace trace Trace runfunc13600878
Ref: a8e13600878
Ref: library/trace trace Trace results13601064
Ref: 452913601064
Ref: library/trace trace CoverageResults13601366
Ref: 452a13601366
Ref: library/trace trace CoverageResults update13601530
Ref: 452b13601530
Ref: library/trace trace CoverageResults write_results13601631
Ref: 452c13601631
Node: tracemalloc — Trace memory allocations13602989
Ref: library/tracemalloc doc13603149
Ref: 452d13603149
Ref: library/tracemalloc module-tracemalloc13603149
Ref: ff13603149
Ref: library/tracemalloc tracemalloc-trace-memory-allocations13603149
Ref: 452e13603149
Ref: library/tracemalloc translation-repo13603149
Ref: 452f13603149
Ref: tracemalloc — Trace memory allocations-Footnote-113604491
Node: Examples<31>13604562
Ref: library/tracemalloc examples13604663
Ref: 453013604663
Node: Display the top 1013604812
Ref: library/tracemalloc display-the-top-1013604907
Ref: 453113604907
Node: Compute differences13606391
Ref: library/tracemalloc compute-differences13606530
Ref: 453313606530
Node: Get the traceback of a memory block13608720
Ref: library/tracemalloc get-the-traceback-of-a-memory-block13608851
Ref: 453613608851
Node: Pretty top13611479
Ref: library/tracemalloc pretty-top13611582
Ref: 453713611582
Node: Record the current and peak size of all traced memory blocks13614044
Ref: library/tracemalloc record-the-current-and-peak-size-of-all-traced-memory-blocks13614151
Ref: 453813614151
Node: API13615838
Ref: library/tracemalloc api13615939
Ref: 453a13615939
Node: Functions<11>13616111
Ref: library/tracemalloc functions13616185
Ref: 453b13616185
Ref: library/tracemalloc tracemalloc clear_traces13616224
Ref: 453c13616224
Ref: library/tracemalloc tracemalloc get_object_traceback13616359
Ref: 1cea13616359
Ref: library/tracemalloc tracemalloc get_traceback_limit13616760
Ref: 453d13616760
Ref: library/tracemalloc tracemalloc get_traced_memory13617078
Ref: 453913617078
Ref: library/tracemalloc tracemalloc reset_peak13617273
Ref: 94513617273
Ref: library/tracemalloc tracemalloc get_tracemalloc_memory13617889
Ref: 453f13617889
Ref: library/tracemalloc tracemalloc is_tracing13618081
Ref: 454013618081
Ref: library/tracemalloc tracemalloc start13618308
Ref: 1ee313618308
Ref: library/tracemalloc tracemalloc stop13619662
Ref: 168713619662
Ref: library/tracemalloc tracemalloc take_snapshot13620096
Ref: 453e13620096
Node: DomainFilter13620779
Ref: library/tracemalloc domainfilter13620868
Ref: 454413620868
Ref: library/tracemalloc tracemalloc DomainFilter13620913
Ref: d1813620913
Ref: library/tracemalloc tracemalloc DomainFilter inclusive13621079
Ref: 454513621079
Ref: library/tracemalloc tracemalloc DomainFilter domain13621379
Ref: 454613621379
Node: Filter13621484
Ref: library/tracemalloc filter13621565
Ref: 454713621565
Ref: library/tracemalloc tracemalloc Filter13621600
Ref: 454813621600
Ref: library/tracemalloc tracemalloc Filter domain13622457
Ref: 454913622457
Ref: library/tracemalloc tracemalloc Filter inclusive13622728
Ref: 454a13622728
Ref: library/tracemalloc tracemalloc Filter lineno13623160
Ref: 454c13623160
Ref: library/tracemalloc tracemalloc Filter filename_pattern13623312
Ref: 454b13623312
Ref: library/tracemalloc tracemalloc Filter all_frames13623426
Ref: 454d13623426
Node: Frame13623833
Ref: library/tracemalloc frame13623910
Ref: 454f13623910
Ref: library/tracemalloc tracemalloc Frame13623943
Ref: 455013623943
Ref: library/tracemalloc tracemalloc Frame filename13624079
Ref: 455113624079
Ref: library/tracemalloc tracemalloc Frame lineno13624142
Ref: 455213624142
Node: Snapshot13624206
Ref: library/tracemalloc snapshot13624286
Ref: 455313624286
Ref: library/tracemalloc tracemalloc Snapshot13624325
Ref: 454313624325
Ref: library/tracemalloc tracemalloc Snapshot compare_to13624503
Ref: 454213624503
Ref: library/tracemalloc tracemalloc Snapshot dump13625231
Ref: 453413625231
Ref: library/tracemalloc tracemalloc Snapshot filter_traces13625367
Ref: 455a13625367
Ref: library/tracemalloc tracemalloc Snapshot load13626030
Ref: 453513626030
Ref: library/tracemalloc tracemalloc Snapshot statistics13626156
Ref: 453213626156
Ref: library/tracemalloc tracemalloc Snapshot traceback_limit13627356
Ref: 454e13627356
Ref: library/tracemalloc tracemalloc Snapshot traces13627575
Ref: 455b13627575
Node: Statistic13627870
Ref: library/tracemalloc statistic13627958
Ref: 456013627958
Ref: library/tracemalloc tracemalloc Statistic13627999
Ref: 455c13627999
Ref: library/tracemalloc tracemalloc Statistic count13628216
Ref: 455813628216
Ref: library/tracemalloc tracemalloc Statistic size13628291
Ref: 455d13628291
Ref: library/tracemalloc tracemalloc Statistic traceback13628378
Ref: 455e13628378
Node: StatisticDiff13628510
Ref: library/tracemalloc statisticdiff13628595
Ref: 456113628595
Ref: library/tracemalloc tracemalloc StatisticDiff13628644
Ref: 455413628644
Ref: library/tracemalloc tracemalloc StatisticDiff count13628937
Ref: 456213628937
Ref: library/tracemalloc tracemalloc StatisticDiff count_diff13629111
Ref: 455713629111
Ref: library/tracemalloc tracemalloc StatisticDiff size13629333
Ref: 455613629333
Ref: library/tracemalloc tracemalloc StatisticDiff size_diff13629529
Ref: 455513629529
Ref: library/tracemalloc tracemalloc StatisticDiff traceback13629763
Ref: 455913629763
Node: Trace13629897
Ref: library/tracemalloc trace13629982
Ref: 456313629982
Ref: library/tracemalloc tracemalloc Trace13630015
Ref: 455f13630015
Ref: library/tracemalloc tracemalloc Trace domain13630241
Ref: 456413630241
Ref: library/tracemalloc tracemalloc Trace size13630519
Ref: 456513630519
Ref: library/tracemalloc tracemalloc Trace traceback13630603
Ref: 456613630603
Node: Traceback13630735
Ref: library/tracemalloc traceback13630798
Ref: 456713630798
Ref: library/tracemalloc tracemalloc Traceback13630839
Ref: bb413630839
Ref: library/tracemalloc tracemalloc Traceback total_nframe13631751
Ref: 454113631751
Ref: library/tracemalloc tracemalloc Traceback format13632060
Ref: bb513632060
Node: Software Packaging and Distribution13633122
Ref: library/distribution doc13633285
Ref: 456913633285
Ref: library/distribution software-packaging-and-distribution13633285
Ref: 456a13633285
Ref: library/distribution translation-repo13633285
Ref: 456b13633285
Ref: Software Packaging and Distribution-Footnote-113633812
Node: ensurepip — Bootstrapping the pip installer13633837
Ref: library/ensurepip doc13634004
Ref: 456c13634004
Ref: library/ensurepip ensurepip-bootstrapping-the-pip-installer13634004
Ref: 456d13634004
Ref: library/ensurepip module-ensurepip13634004
Ref: 5513634004
Ref: ensurepip — Bootstrapping the pip installer-Footnote-113635625
Ref: ensurepip — Bootstrapping the pip installer-Footnote-213635691
Node: Command-line interface<7>13635733
Ref: library/ensurepip command-line-interface13635859
Ref: 456e13635859
Ref: library/ensurepip ensurepip-cli13635859
Ref: 456f13635859
Ref: library/ensurepip cmdoption-ensurepip-root13636608
Ref: 457013636608
Ref: library/ensurepip cmdoption-ensurepip-user13636837
Ref: 457113636837
Ref: library/ensurepip cmdoption-ensurepip-altinstall13637290
Ref: 457213637290
Ref: library/ensurepip cmdoption-ensurepip-default-pip13637417
Ref: 457313637417
Node: Module API13637659
Ref: library/ensurepip module-api13637785
Ref: 457413637785
Ref: library/ensurepip ensurepip version13637887
Ref: 457513637887
Ref: library/ensurepip ensurepip bootstrap13638049
Ref: 442713638049
Node: venv — Creation of virtual environments13639832
Ref: library/venv doc13640056
Ref: 457613640056
Ref: library/venv module-venv13640056
Ref: 11113640056
Ref: library/venv translation-repo13640056
Ref: 457713640056
Ref: library/venv venv-creation-of-virtual-environments13640056
Ref: 457813640056
Ref: library/venv venv-def13640281
Ref: 457913640281
Ref: library/venv venv-intro13640281
Ref: 457a13640281
Ref: venv — Creation of virtual environments-Footnote-113642331
Ref: venv — Creation of virtual environments-Footnote-213642393
Ref: venv — Creation of virtual environments-Footnote-313642431
Ref: venv — Creation of virtual environments-Footnote-413642473
Node: Creating virtual environments13642601
Ref: library/venv creating-virtual-environments13642731
Ref: 457b13642731
Ref: library/venv venv-cli13644485
Ref: 457c13644485
Ref: library/venv cmdoption-venv-arg-ENV_DIR13644485
Ref: 457d13644485
Ref: library/venv cmdoption-venv-system-site-packages13644592
Ref: 457e13644592
Ref: library/venv cmdoption-venv-symlinks13644714
Ref: 457f13644714
Ref: library/venv cmdoption-venv-copies13644841
Ref: 458013644841
Ref: library/venv cmdoption-venv-clear13644967
Ref: 458113644967
Ref: library/venv cmdoption-venv-upgrade13645099
Ref: 458213645099
Ref: library/venv cmdoption-venv-without-pip13645242
Ref: 458313645242
Ref: library/venv cmdoption-venv-prompt13645375
Ref: 458413645375
Ref: library/venv cmdoption-venv-upgrade-deps13645472
Ref: 458513645472
Ref: library/venv cmdoption-venv-without-scm-ignore-files13645569
Ref: 458613645569
Ref: Creating virtual environments-Footnote-113647487
Node: How venvs work13647542
Ref: library/venv how-venvs-work13647687
Ref: 458713647687
Ref: library/venv venv-explanation13647687
Ref: 45013647687
Node: API<2>13652186
Ref: library/venv api13652336
Ref: 458813652336
Ref: library/venv venv-api13652336
Ref: f2913652336
Ref: library/venv venv EnvBuilder13652593
Ref: 26a13652593
Ref: library/venv venv EnvBuilder create13654863
Ref: 458a13654863
Ref: library/venv venv EnvBuilder ensure_directories13656152
Ref: 458b13656152
Ref: library/venv venv EnvBuilder create_configuration13658872
Ref: 458c13658872
Ref: library/venv venv EnvBuilder setup_python13659010
Ref: 458d13659010
Ref: library/venv venv EnvBuilder setup_scripts13659376
Ref: 458e13659376
Ref: library/venv venv EnvBuilder upgrade_dependencies13659525
Ref: 459113659525
Ref: library/venv venv EnvBuilder post_setup13659895
Ref: 458f13659895
Ref: library/venv venv EnvBuilder install_scripts13660130
Ref: 459013660130
Ref: library/venv venv EnvBuilder create_git_ignore_file13661569
Ref: 458913661569
Ref: library/venv venv create13662393
Ref: 26b13662393
Ref: API<2>-Footnote-113663062
Ref: API<2>-Footnote-213663100
Node: An example of extending EnvBuilder13663145
Ref: library/venv an-example-of-extending-envbuilder13663272
Ref: 459213663272
Ref: An example of extending EnvBuilder-Footnote-113673414
Node: zipapp — Manage executable Python zip archives13673461
Ref: library/zipapp doc13673631
Ref: 459313673631
Ref: library/zipapp module-zipapp13673631
Ref: 13013673631
Ref: library/zipapp translation-repo13673631
Ref: 459413673631
Ref: library/zipapp zipapp-manage-executable-python-zip-archives13673631
Ref: 459513673631
Ref: zipapp — Manage executable Python zip archives-Footnote-113674410
Node: Basic Example13674476
Ref: library/zipapp basic-example13674608
Ref: 459813674608
Node: Command-Line Interface<4>13675013
Ref: library/zipapp command-line-interface13675164
Ref: 459913675164
Ref: library/zipapp zipapp-command-line-interface13675164
Ref: 459613675164
Ref: library/zipapp cmdoption-zipapp-o13675660
Ref: 459a13675660
Ref: library/zipapp cmdoption-zipapp-output13675660
Ref: 459b13675660
Ref: library/zipapp cmdoption-zipapp-p13676157
Ref: 459c13676157
Ref: library/zipapp cmdoption-zipapp-python13676157
Ref: 459d13676157
Ref: library/zipapp cmdoption-zipapp-m13676433
Ref: 459e13676433
Ref: library/zipapp cmdoption-zipapp-main13676433
Ref: 459f13676433
Ref: library/zipapp cmdoption-zipapp-c13676862
Ref: 45a013676862
Ref: library/zipapp cmdoption-zipapp-compress13676862
Ref: 45a113676862
Ref: library/zipapp cmdoption-zipapp-info13677139
Ref: 45a213677139
Ref: library/zipapp cmdoption-zipapp-h13677342
Ref: 45a313677342
Ref: library/zipapp cmdoption-zipapp-help13677342
Ref: 45a413677342
Node: Python API13677410
Ref: library/zipapp python-api13677560
Ref: 45a513677560
Ref: library/zipapp zipapp-python-api13677560
Ref: 459713677560
Ref: library/zipapp zipapp create_archive13677648
Ref: bce13677648
Ref: library/zipapp zipapp get_interpreter13681441
Ref: 45a613681441
Node: Examples<32>13681798
Ref: library/zipapp examples13681949
Ref: 45a713681949
Ref: library/zipapp zipapp-examples13681949
Ref: 45a813681949
Node: Specifying the Interpreter13683320
Ref: library/zipapp specifying-the-interpreter13683505
Ref: 45a913683505
Ref: library/zipapp zipapp-specifying-the-interpreter13683505
Ref: 45aa13683505
Node: Creating Standalone Applications with zipapp13684744
Ref: library/zipapp creating-standalone-applications-with-zipapp13684958
Ref: 45ab13684958
Node: Caveats13686663
Ref: library/zipapp caveats13686751
Ref: 45ac13686751
Node: The Python Zip Application Archive Format13687490
Ref: library/zipapp the-python-zip-application-archive-format13687669
Ref: 45ad13687669
Node: Python Runtime Services13689572
Ref: library/python doc13689738
Ref: 45ae13689738
Ref: library/python python13689738
Ref: 45af13689738
Ref: library/python python-runtime-services13689738
Ref: 45b013689738
Ref: library/python translation-repo13689738
Ref: 45b113689738
Node: sys — System-specific parameters and functions13690688
Ref: library/sys doc13690850
Ref: 45b213690850
Ref: library/sys module-sys13690850
Ref: d913690850
Ref: library/sys sys-system-specific-parameters-and-functions13690850
Ref: 45b313690850
Ref: library/sys sys abiflags13691274
Ref: a7213691274
Ref: library/sys sys addaudithook13691638
Ref: 441e13691638
Ref: library/sys sys argv13693854
Ref: 12ab13693854
Ref: library/sys auditing13694782
Ref: 1a1513694782
Ref: library/sys sys audit13694782
Ref: 16be13694782
Ref: library/sys sys base_exec_prefix13696182
Ref: 3f113696182
Ref: library/sys sys base_prefix13696813
Ref: 3f213696813
Ref: library/sys sys byteorder13697429
Ref: 235313697429
Ref: library/sys sys builtin_module_names13697685
Ref: 1dfd13697685
Ref: library/sys sys call_tracing13698018
Ref: 196813698018
Ref: library/sys sys copyright13698541
Ref: 45b413698541
Ref: library/sys sys _clear_type_cache13698649
Ref: 178413698649
Ref: library/sys sys _clear_internal_caches13699094
Ref: 178313699094
Ref: library/sys sys _current_frames13699333
Ref: 148113699333
Ref: library/sys sys _current_exceptions13700202
Ref: 4c513700202
Ref: library/sys sys breakpointhook13700913
Ref: af013700913
Ref: library/sys sys _debugmallocstats13702813
Ref: 45b513702813
Ref: library/sys sys dllhandle13703296
Ref: 45b613703296
Ref: library/sys sys displayhook13703418
Ref: 156f13703418
Ref: library/sys sys dont_write_bytecode13704945
Ref: 45b713704945
Ref: library/sys sys _emscripten_info13705344
Ref: 193413705344
Ref: library/sys sys _emscripten_info emscripten_version13705559
Ref: 45b813705559
Ref: library/sys sys _emscripten_info runtime13705719
Ref: 45b913705719
Ref: library/sys sys _emscripten_info pthreads13705874
Ref: 45ba13705874
Ref: library/sys sys _emscripten_info shared_memory13705999
Ref: 45bb13705999
Ref: library/sys sys pycache_prefix13706197
Ref: 9af13706197
Ref: library/sys sys excepthook13707170
Ref: 81113707170
Ref: library/sys sys __breakpointhook__13708535
Ref: 45bc13708535
Ref: library/sys sys __displayhook__13708568
Ref: 45bd13708568
Ref: library/sys sys __excepthook__13708598
Ref: 45be13708598
Ref: library/sys sys __unraisablehook__13708627
Ref: 45bf13708627
Ref: library/sys sys exception13709139
Ref: 68e13709139
Ref: library/sys sys exc_info13709609
Ref: 68d13709609
Ref: library/sys sys exec_prefix13710599
Ref: 3b513710599
Ref: library/sys sys executable13711518
Ref: 3bb13711518
Ref: library/sys sys exit13711819
Ref: 139413711819
Ref: library/sys sys flags13713485
Ref: 68f13713485
Ref: library/sys sys flags debug13713657
Ref: 45c013713657
Ref: library/sys sys flags inspect13713857
Ref: 15db13713857
Ref: library/sys sys flags interactive13714059
Ref: 45c113714059
Ref: library/sys sys flags isolated13714254
Ref: 45c213714254
Ref: library/sys sys flags optimize13714451
Ref: 45c313714451
Ref: library/sys sys flags dont_write_bytecode13714678
Ref: 45c413714678
Ref: library/sys sys flags no_user_site13714869
Ref: 45c513714869
Ref: library/sys sys flags no_site13715062
Ref: 45c613715062
Ref: library/sys sys flags ignore_environment13715271
Ref: 45c713715271
Ref: library/sys sys flags verbose13715457
Ref: 45c813715457
Ref: library/sys sys flags bytes_warning13715661
Ref: 45c913715661
Ref: library/sys sys flags quiet13715850
Ref: 45ca13715850
Ref: library/sys sys flags hash_randomization13716061
Ref: 45cb13716061
Ref: library/sys sys flags dev_mode13716249
Ref: 1c3313716249
Ref: library/sys sys flags utf8_mode13716549
Ref: 45cc13716549
Ref: library/sys sys flags safe_path13716751
Ref: 23613716751
Ref: library/sys sys flags int_max_str_digits13716957
Ref: 243313716957
Ref: library/sys sys flags warn_default_encoding13717294
Ref: 45cd13717294
Ref: library/sys sys float_info13718275
Ref: 1b7b13718275
Ref: library/sys sys float_info epsilon13719233
Ref: 45cf13719233
Ref: library/sys sys float_info dig13719929
Ref: 45d013719929
Ref: library/sys sys float_info mant_dig13720440
Ref: 45d113720440
Ref: library/sys sys float_info max13720932
Ref: 45d213720932
Ref: library/sys sys float_info max_exp13721315
Ref: 45d313721315
Ref: library/sys sys float_info max_10_exp13721793
Ref: 45d413721793
Ref: library/sys sys float_info min13722313
Ref: 45d513722313
Ref: library/sys sys float_info min_exp13723122
Ref: 45d613723122
Ref: library/sys sys float_info min_10_exp13723590
Ref: 45d713723590
Ref: library/sys sys float_info radix13724006
Ref: 45d813724006
Ref: library/sys sys float_info rounds13724375
Ref: 45d913724375
Ref: library/sys sys float_repr_style13727269
Ref: 134313727269
Ref: library/sys sys getallocatedblocks13727810
Ref: 100013727810
Ref: library/sys sys getunicodeinternedsize13728443
Ref: 45da13728443
Ref: library/sys sys getandroidapilevel13728585
Ref: ba813728585
Ref: library/sys sys getdefaultencoding13728930
Ref: 45db13728930
Ref: library/sys sys getdlopenflags13729100
Ref: 155e13729100
Ref: library/sys sys getfilesystemencoding13729413
Ref: c7a13729413
Ref: library/sys sys getfilesystemencodeerrors13730807
Ref: d0d13730807
Ref: library/sys sys get_int_max_str_digits13731537
Ref: 163413731537
Ref: library/sys sys getrefcount13731765
Ref: 45dc13731765
Ref: library/sys sys getrecursionlimit13732531
Ref: 4c713732531
Ref: library/sys sys getsizeof13732843
Ref: 187e13732843
Ref: library/sys sys getswitchinterval13733781
Ref: 95313733781
Ref: library/sys sys _getframe13733964
Ref: 6e413733964
Ref: library/sys sys _getframemodulename13734620
Ref: 188213734620
Ref: library/sys sys getobjects13735352
Ref: 42a13735352
Ref: library/sys sys getprofile13736477
Ref: 142e13736477
Ref: library/sys sys gettrace13736578
Ref: 142f13736578
Ref: library/sys sys getwindowsversion13737006
Ref: d0e13737006
Ref: library/sys sys get_asyncgen_hooks13739535
Ref: 196913739535
Ref: library/sys sys get_coroutine_origin_tracking_depth13740144
Ref: ba913740144
Ref: library/sys sys hash_info13740496
Ref: 103a13740496
Ref: library/sys sys hash_info width13740709
Ref: 45df13740709
Ref: library/sys sys hash_info modulus13740796
Ref: 235913740796
Ref: library/sys sys hash_info inf13740895
Ref: 45e013740895
Ref: library/sys sys hash_info nan13740989
Ref: 45e113740989
Ref: library/sys sys hash_info imag13741070
Ref: 45e213741070
Ref: library/sys sys hash_info algorithm13741180
Ref: 45e313741180
Ref: library/sys sys hash_info hash_bits13741310
Ref: 45e413741310
Ref: library/sys sys hash_info seed_bits13741409
Ref: 45e513741409
Ref: library/sys sys hash_info cutoff13741508
Ref: 45e613741508
Ref: library/sys sys hexversion13741762
Ref: 45e713741762
Ref: library/sys sys implementation13742656
Ref: 51a13742656
Ref: library/sys sys int_info13744853
Ref: 12da13744853
Ref: library/sys sys int_info bits_per_digit13745022
Ref: 45e913745022
Ref: library/sys sys int_info sizeof_digit13745208
Ref: 45ea13745208
Ref: library/sys sys int_info default_max_str_digits13745321
Ref: 243413745321
Ref: library/sys sys int_info str_digits_check_threshold13745507
Ref: 45eb13745507
Ref: library/sys sys __interactivehook__13745900
Ref: 100213745900
Ref: library/sys sys intern13746451
Ref: 132313746451
Ref: library/sys sys _is_gil_enabled13747231
Ref: 45ec13747231
Ref: library/sys sys is_finalizing13747516
Ref: a9e13747516
Ref: library/sys sys last_exc13747778
Ref: 4c113747778
Ref: library/sys sys _is_interned13748351
Ref: 25013748351
Ref: library/sys sys last_type13748632
Ref: 4c213748632
Ref: library/sys sys last_value13748656
Ref: 4c313748656
Ref: library/sys sys last_traceback13748681
Ref: 4c413748681
Ref: library/sys sys maxsize13748910
Ref: 120a13748910
Ref: library/sys sys maxunicode13749132
Ref: 108a13749132
Ref: library/sys sys meta_path13749531
Ref: d5313749531
Ref: library/sys sys modules13750823
Ref: 165513750823
Ref: library/sys sys orig_argv13751431
Ref: 84613751431
Ref: library/sys sys path13751895
Ref: 3b713751895
Ref: library/sys sys path_hooks13753169
Ref: 105f13753169
Ref: library/sys sys path_importer_cache13753460
Ref: 5e713753460
Ref: library/sys sys platform13753860
Ref: a9c13753860
Ref: library/sys sys platlibdir13756198
Ref: 94213756198
Ref: library/sys sys prefix13757202
Ref: 3b913757202
Ref: library/sys sys ps113757830
Ref: 1eed13757830
Ref: library/sys sys ps213757848
Ref: 1eee13757848
Ref: library/sys sys setdlopenflags13758324
Ref: 116313758324
Ref: library/sys sys set_int_max_str_digits13758925
Ref: 18e013758925
Ref: library/sys sys setprofile13759162
Ref: 154d13759162
Ref: library/sys sys setrecursionlimit13761567
Ref: 4c613761567
Ref: library/sys sys setswitchinterval13762359
Ref: 95413762359
Ref: library/sys sys settrace13762938
Ref: 154e13762938
Ref: library/sys sys set_asyncgen_hooks13767687
Ref: 173013767687
Ref: library/sys sys set_coroutine_origin_tracking_depth13768798
Ref: baa13768798
Ref: library/sys sys activate_stack_trampoline13769621
Ref: 47213769621
Ref: library/sys sys deactivate_stack_trampoline13769995
Ref: 47313769995
Ref: library/sys sys is_stack_trampoline_active13770248
Ref: 47413770248
Ref: library/sys sys _enablelegacywindowsfsencoding13770432
Ref: 2ae13770432
Ref: library/sys sys stdin13771401
Ref: 54013771401
Ref: library/sys sys stdout13771421
Ref: aec13771421
Ref: library/sys sys stderr13771442
Ref: 94313771442
Ref: library/sys sys __stdin__13774595
Ref: 45ee13774595
Ref: library/sys sys __stdout__13774619
Ref: 2a4f13774619
Ref: library/sys sys __stderr__13774644
Ref: 43a313774644
Ref: library/sys sys stdlib_module_names13775609
Ref: 84713775609
Ref: library/sys sys thread_info13776344
Ref: 119413776344
Ref: library/sys sys thread_info name13776461
Ref: 45ef13776461
Ref: library/sys sys thread_info lock13776815
Ref: 45f013776815
Ref: library/sys sys thread_info version13777114
Ref: 45f113777114
Ref: library/sys sys tracebacklimit13777311
Ref: 16e213777311
Ref: library/sys sys unraisablehook13777675
Ref: 1f713777675
Ref: library/sys sys version13779503
Ref: 17813779503
Ref: library/sys sys api_version13779905
Ref: 45f213779905
Ref: library/sys sys version_info13780093
Ref: 6a313780093
Ref: library/sys sys warnoptions13780714
Ref: 3b313780714
Ref: library/sys sys winver13780933
Ref: 45f313780933
Ref: library/sys sys _xoptions13781569
Ref: 1ee713781569
Ref: library/sys c9913782370
Ref: 45ce13782370
Ref: sys — System-specific parameters and functions-Footnote-113782582
Ref: sys — System-specific parameters and functions-Footnote-213782624
Ref: sys — System-specific parameters and functions-Footnote-313782666
Ref: sys — System-specific parameters and functions-Footnote-413782708
Ref: sys — System-specific parameters and functions-Footnote-513782813
Ref: sys — System-specific parameters and functions-Footnote-613782855
Ref: sys — System-specific parameters and functions-Footnote-713782897
Ref: sys — System-specific parameters and functions-Footnote-813782939
Ref: sys — System-specific parameters and functions-Footnote-913782981
Ref: sys — System-specific parameters and functions-Footnote-1013783023
Ref: sys — System-specific parameters and functions-Footnote-1113783066
Ref: sys — System-specific parameters and functions-Footnote-1213783109
Ref: sys — System-specific parameters and functions-Footnote-1313783152
Ref: sys — System-specific parameters and functions-Footnote-1413783195
Ref: sys — System-specific parameters and functions-Footnote-1513783238
Ref: sys — System-specific parameters and functions-Footnote-1613783319
Ref: sys — System-specific parameters and functions-Footnote-1713783362
Ref: sys — System-specific parameters and functions-Footnote-1813783405
Node: sys monitoring — Execution event monitoring13783448
Ref: library/sys monitoring doc13783687
Ref: 45f413783687
Ref: library/sys monitoring module-sys monitoring13783687
Ref: da13783687
Ref: library/sys monitoring sys-monitoring-execution-event-monitoring13783687
Ref: 45f513783687
Ref: library/sys monitoring translation-repo13783687
Ref: 45f613783687
Node: Tool identifiers13784682
Ref: library/sys monitoring tool-identifiers13784795
Ref: 45f713784795
Node: Registering and using tools13785352
Ref: library/sys monitoring registering-and-using-tools13785432
Ref: 45fa13785432
Ref: library/sys monitoring sys monitoring use_tool_id13785507
Ref: 45fb13785507
Ref: library/sys monitoring sys monitoring free_tool_id13785764
Ref: 45fc13785764
Ref: library/sys monitoring sys monitoring get_tool13786178
Ref: 45fd13786178
Node: Events13786681
Ref: library/sys monitoring events13786828
Ref: 45f813786828
Ref: library/sys monitoring monitoring-event-BRANCH13786898
Ref: 45fe13786898
Ref: library/sys monitoring monitoring-event-CALL13786996
Ref: 175113786996
Ref: library/sys monitoring monitoring-event-C_RAISE13787106
Ref: 45ff13787106
Ref: library/sys monitoring monitoring-event-C_RETURN13787268
Ref: 460013787268
Ref: library/sys monitoring monitoring-event-EXCEPTION_HANDLED13787420
Ref: 460113787420
Ref: library/sys monitoring monitoring-event-INSTRUCTION13787514
Ref: 460213787514
Ref: library/sys monitoring monitoring-event-JUMP13787619
Ref: 460313787619
Ref: library/sys monitoring monitoring-event-LINE13787732
Ref: 460413787732
Ref: library/sys monitoring monitoring-event-PY_RESUME13787897
Ref: 460513787897
Ref: library/sys monitoring monitoring-event-PY_RETURN13788068
Ref: 460613788068
Ref: library/sys monitoring monitoring-event-PY_START13788247
Ref: 460713788247
Ref: library/sys monitoring monitoring-event-PY_THROW13788418
Ref: 460813788418
Ref: library/sys monitoring monitoring-event-PY_UNWIND13788532
Ref: 460913788532
Ref: library/sys monitoring monitoring-event-PY_YIELD13788649
Ref: 460a13788649
Ref: library/sys monitoring monitoring-event-RAISE13788825
Ref: 16f813788825
Ref: library/sys monitoring monitoring-event-RERAISE13788972
Ref: 460c13788972
Ref: library/sys monitoring monitoring-event-STOP_ITERATION13789118
Ref: 460b13789118
Ref: library/sys monitoring monitoring-event-NO_EVENTS13789670
Ref: 460e13789670
Node: Local events13789998
Ref: library/sys monitoring local-events13790078
Ref: 460f13790078
Ref: library/sys monitoring monitoring-event-local13790078
Ref: 461013790078
Node: Ancillary events13790564
Ref: library/sys monitoring ancillary-events13790665
Ref: 461113790665
Node: Other events13791087
Ref: library/sys monitoring monitoring-event-global13791200
Ref: 461213791200
Ref: library/sys monitoring other-events13791200
Ref: 461313791200
Node: The STOP_ITERATION event13791547
Ref: library/sys monitoring the-stop-iteration-event13791635
Ref: 460d13791635
Ref: The STOP_ITERATION event-Footnote-113792271
Node: Turning events on and off13792352
Ref: library/sys monitoring turning-events-on-and-off13792513
Ref: 461513792513
Node: Setting events globally13792874
Ref: library/sys monitoring setting-events-globally13792990
Ref: 461613792990
Ref: library/sys monitoring sys monitoring get_events13793140
Ref: 461713793140
Ref: library/sys monitoring sys monitoring set_events13793270
Ref: 461813793270
Node: Per code object events13793520
Ref: library/sys monitoring per-code-object-events13793661
Ref: 461913793661
Ref: library/sys monitoring sys monitoring get_local_events13793990
Ref: 461a13793990
Ref: library/sys monitoring sys monitoring set_local_events13794147
Ref: 461b13794147
Node: Disabling events13794581
Ref: library/sys monitoring disabling-events13794690
Ref: 461c13794690
Ref: library/sys monitoring sys monitoring DISABLE13794745
Ref: 461413794745
Ref: library/sys monitoring sys monitoring restart_events13795580
Ref: 461d13795580
Node: Registering callback functions13795742
Ref: library/sys monitoring callbacks13795888
Ref: 45f913795888
Ref: library/sys monitoring registering-callback-functions13795888
Ref: 461e13795888
Ref: library/sys monitoring sys monitoring register_callback13796011
Ref: 442c13796011
Node: Callback function arguments13796729
Ref: library/sys monitoring callback-function-arguments13796823
Ref: 461f13796823
Ref: library/sys monitoring sys monitoring MISSING13796900
Ref: 462013796900
Node: sysconfig — Provide access to Python’s configuration information13798558
Ref: library/sysconfig doc13798778
Ref: 462113798778
Ref: library/sysconfig module-sysconfig13798778
Ref: db13798778
Ref: library/sysconfig sysconfig-provide-access-to-python-s-configuration-information13798778
Ref: 462213798778
Ref: library/sysconfig translation-repo13798778
Ref: 462313798778
Ref: sysconfig — Provide access to Python’s configuration information-Footnote-113799509
Node: Configuration variables13799575
Ref: library/sysconfig configuration-variables13799730
Ref: 462413799730
Ref: library/sysconfig sysconfig get_config_vars13800217
Ref: 106913800217
Ref: library/sysconfig sysconfig get_config_var13800588
Ref: 106813800588
Node: Installation paths13801031
Ref: library/sysconfig id113801206
Ref: 462513801206
Ref: library/sysconfig installation-paths13801206
Ref: 69213801206
Node: User scheme13803543
Ref: library/sysconfig sysconfig-user-scheme13803706
Ref: 1eef13803706
Ref: library/sysconfig user-scheme13803706
Ref: 462613803706
Node: posix_user13804235
Ref: library/sysconfig posix-user13804309
Ref: 462713804309
Node: nt_user13805153
Ref: library/sysconfig nt-user13805254
Ref: 462813805254
Node: osx_framework_user13806086
Ref: library/sysconfig osx-framework-user13806168
Ref: 462913806168
Node: Home scheme13807008
Ref: library/sysconfig home-scheme13807166
Ref: 462a13807166
Ref: library/sysconfig sysconfig-home-scheme13807166
Ref: 462b13807166
Node: posix_home13807647
Ref: library/sysconfig posix-home13807705
Ref: 462c13807705
Node: Prefix scheme13808555
Ref: library/sysconfig prefix-scheme13808729
Ref: 462d13808729
Ref: library/sysconfig sysconfig-prefix-scheme13808729
Ref: 462e13808729
Node: posix_prefix13810069
Ref: library/sysconfig posix-prefix13810142
Ref: 462f13810142
Node: nt13811071
Ref: library/sysconfig nt13811144
Ref: 463013811144
Node: Installation path functions13811985
Ref: library/sysconfig installation-path-functions13812166
Ref: 463113812166
Ref: library/sysconfig sysconfig get_scheme_names13812323
Ref: 463213812323
Ref: library/sysconfig sysconfig get_default_scheme13812457
Ref: 195a13812457
Ref: library/sysconfig sysconfig get_preferred_scheme13812817
Ref: 69313812817
Ref: library/sysconfig sysconfig _get_preferred_schemes13813404
Ref: 463313813404
Ref: library/sysconfig sysconfig get_path_names13814071
Ref: 463413814071
Ref: library/sysconfig sysconfig get_path13814206
Ref: 137813814206
Ref: library/sysconfig sysconfig get_paths13815419
Ref: 128a13815419
Node: Other functions<3>13816037
Ref: library/sysconfig other-functions13816226
Ref: 463513816226
Ref: library/sysconfig sysconfig get_python_version13816279
Ref: 128913816279
Ref: library/sysconfig sysconfig get_platform13816450
Ref: 128813816450
Ref: library/sysconfig sysconfig is_python_build13817464
Ref: 2dd13817464
Ref: library/sysconfig sysconfig parse_config_h13817755
Ref: 463613817755
Ref: library/sysconfig sysconfig get_config_h_filename13818149
Ref: 463713818149
Ref: library/sysconfig sysconfig get_makefile_filename13818242
Ref: 463813818242
Ref: library/sysconfig sysconfig-cli13818332
Ref: 463913818332
Node: Command-line usage<4>13818333
Ref: library/sysconfig command-line-usage13818486
Ref: 463a13818486
Ref: library/sysconfig using-sysconfig-as-a-script13818486
Ref: 463b13818486
Node: builtins — Built-in objects13819534
Ref: library/builtins doc13819748
Ref: 463c13819748
Ref: library/builtins builtins-built-in-objects13819748
Ref: 463d13819748
Ref: library/builtins module-builtins13819748
Ref: 1213819748
Ref: library/builtins translation-repo13819748
Ref: 463e13819748
Node: __main__ — Top-level code environment13821320
Ref: library/__main__ doc13821494
Ref: 463f13821494
Ref: library/__main__ main-top-level-code-environment13821494
Ref: 464013821494
Ref: library/__main__ module-__main__13821494
Ref: 113821494
Ref: library/__main__ translation-repo13821494
Ref: 464113821494
Node: __name__ == '__main__'13822327
Ref: library/__main__ name-equals-main13822464
Ref: 464213822464
Ref: library/__main__ name-main13822464
Ref: 464313822464
Node: What is the “top-level code environment”?13823240
Ref: library/__main__ what-is-the-top-level-code-environment13823368
Ref: 464413823368
Node: Idiomatic Usage13825387
Ref: library/__main__ idiomatic-usage13825548
Ref: 464513825548
Node: Packaging Considerations13827528
Ref: library/__main__ packaging-considerations13827635
Ref: 464613827635
Ref: Packaging Considerations-Footnote-113829139
Ref: Packaging Considerations-Footnote-213829168
Node: __main__ py in Python Packages13829206
Ref: library/__main__ main-py-in-python-packages13829367
Ref: 464713829367
Node: Idiomatic Usage<2>13830774
Ref: library/__main__ id113830859
Ref: 464813830859
Node: import __main__13832200
Ref: library/__main__ import-main13832330
Ref: 464913832330
Node: warnings — Warning control13835508
Ref: library/warnings doc13835681
Ref: 464a13835681
Ref: library/warnings module-warnings13835681
Ref: 11213835681
Ref: library/warnings translation-repo13835681
Ref: 464b13835681
Ref: library/warnings warnings-warning-control13835681
Ref: 464c13835681
Ref: warnings — Warning control-Footnote-113837995
Node: Warning Categories13838063
Ref: library/warnings id113838174
Ref: 465013838174
Ref: library/warnings warning-categories13838174
Ref: 246b13838174
Node: The Warnings Filter13842361
Ref: library/warnings the-warnings-filter13842513
Ref: 465113842513
Ref: library/warnings warning-filter13842513
Ref: 8d213842513
Node: Repeated Warning Suppression Criteria13845698
Ref: library/warnings id213845826
Ref: 465213845826
Ref: library/warnings repeated-warning-suppression-criteria13845826
Ref: 465313845826
Node: Describing Warning Filters13846461
Ref: library/warnings describing-warning-filters13846620
Ref: 1ee113846620
Ref: library/warnings id313846620
Ref: 465413846620
Node: Default Warning Filter13848339
Ref: library/warnings default-warning-filter13848490
Ref: 465513848490
Ref: library/warnings id413848490
Ref: 465613848490
Node: Overriding the default filter13849590
Ref: library/warnings overriding-the-default-filter13849706
Ref: 465713849706
Ref: library/warnings warning-disable13849706
Ref: 465813849706
Node: Temporarily Suppressing Warnings13851141
Ref: library/warnings temporarily-suppressing-warnings13851291
Ref: 465913851291
Ref: library/warnings warning-suppress13851291
Ref: 465a13851291
Node: Testing Warnings13852307
Ref: library/warnings testing-warnings13852484
Ref: 465b13852484
Ref: library/warnings warning-testing13852484
Ref: 465c13852484
Node: Updating Code For New Versions of Dependencies13854546
Ref: library/warnings updating-code-for-new-versions-of-dependencies13854710
Ref: 465d13854710
Ref: library/warnings warning-ignored13854710
Ref: 42f213854710
Node: Available Functions13856088
Ref: library/warnings available-functions13856262
Ref: 465e13856262
Ref: library/warnings warning-functions13856262
Ref: 465f13856262
Ref: library/warnings warnings warn13856323
Ref: 156913856323
Ref: library/warnings warnings warn_explicit13858899
Ref: d2813858899
Ref: library/warnings warnings showwarning13860274
Ref: 464f13860274
Ref: library/warnings warnings formatwarning13860905
Ref: 1ba613860905
Ref: library/warnings warnings filterwarnings13861330
Ref: 14f813861330
Ref: library/warnings warnings simplefilter13862006
Ref: 6c413862006
Ref: library/warnings warnings resetwarnings13862442
Ref: 464e13862442
Ref: library/warnings warnings deprecated13862710
Ref: 16013862710
Ref: Available Functions-Footnote-113864579
Node: Available Context Managers13864621
Ref: library/warnings available-context-managers13864740
Ref: 466013864740
Ref: library/warnings warnings catch_warnings13864815
Ref: 58713864815
Node: dataclasses — Data Classes13866484
Ref: library/dataclasses doc13866670
Ref: 466113866670
Ref: library/dataclasses dataclasses-data-classes13866670
Ref: 466213866670
Ref: library/dataclasses module-dataclasses13866670
Ref: 2f13866670
Ref: library/dataclasses translation-repo13866670
Ref: 466313866670
Ref: dataclasses — Data Classes-Footnote-113868377
Ref: dataclasses — Data Classes-Footnote-213868448
Ref: dataclasses — Data Classes-Footnote-313868490
Node: Module contents<5>13868532
Ref: library/dataclasses module-contents13868644
Ref: 466413868644
Ref: library/dataclasses dataclasses dataclass13868695
Ref: 1cb13868695
Ref: library/dataclasses dataclasses field13878678
Ref: 1bb113878678
Ref: library/dataclasses dataclasses Field13883285
Ref: 240d13883285
Ref: library/dataclasses dataclasses InitVar13884041
Ref: 195913884041
Ref: library/dataclasses dataclasses fields13884448
Ref: 185713884448
Ref: library/dataclasses dataclasses asdict13884827
Ref: 183613884827
Ref: library/dataclasses dataclasses astuple13885869
Ref: 183e13885869
Ref: library/dataclasses dataclasses make_dataclass13886608
Ref: 185913886608
Ref: library/dataclasses dataclasses replace13888403
Ref: 180913888403
Ref: library/dataclasses dataclasses is_dataclass13889898
Ref: 19bb13889898
Ref: library/dataclasses dataclasses MISSING13890377
Ref: 466713890377
Ref: library/dataclasses dataclasses KW_ONLY13890480
Ref: 466613890480
Ref: library/dataclasses dataclasses FrozenInstanceError13891423
Ref: 466a13891423
Ref: Module contents<5>-Footnote-113891734
Ref: Module contents<5>-Footnote-213891789
Node: Post-init processing13891844
Ref: library/dataclasses id113891980
Ref: 466b13891980
Ref: library/dataclasses post-init-processing13891980
Ref: 466c13891980
Ref: library/dataclasses dataclasses __post_init__13892041
Ref: 466913892041
Node: Class variables13893802
Ref: library/dataclasses class-variables13893939
Ref: 466d13893939
Ref: library/dataclasses dataclasses-class-variables13893939
Ref: 466e13893939
Ref: Class variables-Footnote-113894497
Node: Init-only variables13894539
Ref: library/dataclasses dataclasses-init-only-variables13894672
Ref: 466813894672
Ref: library/dataclasses init-only-variables13894672
Ref: 466f13894672
Node: Frozen instances13895895
Ref: library/dataclasses dataclasses-frozen13896027
Ref: 466513896027
Ref: library/dataclasses frozen-instances13896027
Ref: 467013896027
Node: Inheritance<2>13896624
Ref: library/dataclasses dataclasses-inheritance13896787
Ref: 467113896787
Ref: library/dataclasses inheritance13896787
Ref: 467213896787
Node: Re-ordering of keyword-only parameters in __init__13897843
Ref: library/dataclasses re-ordering-of-keyword-only-parameters-in-init13898015
Ref: 467313898015
Node: Default factory functions13899270
Ref: library/dataclasses default-factory-functions13899450
Ref: 467413899450
Node: Mutable default values13900068
Ref: library/dataclasses mutable-default-values13900221
Ref: 467513900221
Node: Descriptor-typed fields13902246
Ref: library/dataclasses descriptor-typed-fields13902365
Ref: 467613902365
Node: contextlib — Utilities for with-statement contexts13904343
Ref: library/contextlib doc13904530
Ref: 467713904530
Ref: library/contextlib contextlib-utilities-for-with-statement-contexts13904530
Ref: 467813904530
Ref: library/contextlib module-contextlib13904530
Ref: 2313904530
Ref: library/contextlib translation-repo13904530
Ref: 467913904530
Ref: contextlib — Utilities for with-statement contexts-Footnote-113905192
Node: Utilities13905262
Ref: library/contextlib utilities13905392
Ref: 467a13905392
Ref: library/contextlib contextlib AbstractContextManager13905464
Ref: cb113905464
Ref: library/contextlib contextlib AbstractAsyncContextManager13905914
Ref: b4313905914
Ref: library/contextlib contextlib contextmanager13906381
Ref: 124713906381
Ref: library/contextlib contextlib asynccontextmanager13909384
Ref: b4213909384
Ref: library/contextlib contextlib closing13911392
Ref: 13d613911392
Ref: library/contextlib contextlib aclosing13912633
Ref: 7f213912633
Ref: library/contextlib simplifying-support-for-single-optional-context-managers13913754
Ref: 467b13913754
Ref: library/contextlib contextlib nullcontext13913754
Ref: 7f313913754
Ref: library/contextlib contextlib suppress13915472
Ref: f5d13915472
Ref: library/contextlib contextlib redirect_stdout13917044
Ref: e1813917044
Ref: library/contextlib contextlib redirect_stderr13918531
Ref: e1713918531
Ref: library/contextlib contextlib chdir13918795
Ref: 60f13918795
Ref: library/contextlib contextlib ContextDecorator13919526
Ref: 124613919526
Ref: library/contextlib contextlib AsyncContextDecorator13921989
Ref: 7f413921989
Ref: library/contextlib contextlib ExitStack13923081
Ref: b4113923081
Ref: library/contextlib contextlib ExitStack enter_context13925072
Ref: 5d613925072
Ref: library/contextlib contextlib ExitStack push13925662
Ref: 467d13925662
Ref: library/contextlib contextlib ExitStack callback13926554
Ref: a9213926554
Ref: library/contextlib contextlib ExitStack pop_all13927010
Ref: 467e13927010
Ref: library/contextlib contextlib ExitStack close13928056
Ref: 467f13928056
Ref: library/contextlib contextlib AsyncExitStack13928344
Ref: b4413928344
Ref: library/contextlib contextlib AsyncExitStack enter_async_context13928711
Ref: 5d913928711
Ref: library/contextlib contextlib AsyncExitStack push_async_exit13929046
Ref: 468113929046
Ref: library/contextlib contextlib AsyncExitStack push_async_callback13929225
Ref: a9313929225
Ref: library/contextlib contextlib AsyncExitStack aclose13929391
Ref: 468013929391
Node: Examples and Recipes<3>13930000
Ref: library/contextlib examples-and-recipes13930189
Ref: 468213930189
Node: Supporting a variable number of context managers13930633
Ref: library/contextlib supporting-a-variable-number-of-context-managers13930792
Ref: 468313930792
Node: Catching exceptions from __enter__ methods13931834
Ref: library/contextlib catching-exceptions-from-enter-methods13932044
Ref: 468413932044
Node: Cleaning up in an __enter__ implementation13933209
Ref: library/contextlib cleaning-up-in-an-enter-implementation13933422
Ref: 468513933422
Node: Replacing any use of try-finally and flag variables13935325
Ref: library/contextlib replacing-any-use-of-try-finally-and-flag-variables13935543
Ref: 468613935543
Node: Using a context manager as a function decorator13938055
Ref: library/contextlib using-a-context-manager-as-a-function-decorator13938222
Ref: 468713938222
Ref: Using a context manager as a function decorator-Footnote-113940058
Node: Single use reusable and reentrant context managers13940100
Ref: library/contextlib single-use-reusable-and-reentrant-cms13940271
Ref: f5f13940271
Ref: library/contextlib single-use-reusable-and-reentrant-context-managers13940271
Ref: 468813940271
Node: Reentrant context managers13941809
Ref: library/contextlib reentrant-cms13941956
Ref: 467c13941956
Ref: library/contextlib reentrant-context-managers13941956
Ref: 468913941956
Node: Reusable context managers13943493
Ref: library/contextlib reusable-cms13943640
Ref: 468a13943640
Ref: library/contextlib reusable-context-managers13943640
Ref: 468b13943640
Node: abc — Abstract Base Classes13946318
Ref: library/abc doc13946501
Ref: 468c13946501
Ref: library/abc abc-abstract-base-classes13946501
Ref: 468d13946501
Ref: library/abc module-abc13946501
Ref: 413946501
Ref: library/abc translation-repo13946501
Ref: 468e13946501
Ref: library/abc abc ABC13947491
Ref: f4e13947491
Ref: library/abc abc ABCMeta13948309
Ref: f4f13948309
Ref: library/abc abc ABCMeta register13949083
Ref: 10cc13949083
Ref: library/abc abc ABCMeta __subclasshook__13949760
Ref: 26e813949760
Ref: library/abc abc abstractmethod13952673
Ref: 10c913952673
Ref: library/abc abc abstractclassmethod13955818
Ref: 10ca13955818
Ref: library/abc abc abstractstaticmethod13956538
Ref: 10cb13956538
Ref: library/abc abc abstractproperty13957260
Ref: 10c813957260
Ref: library/abc abc get_cache_token13958664
Ref: f4d13958664
Ref: library/abc abc update_abstractmethods13959044
Ref: 468f13959044
Ref: abc — Abstract Base Classes-Footnote-113959699
Ref: abc — Abstract Base Classes-Footnote-213959762
Ref: abc — Abstract Base Classes-Footnote-313959804
Ref: abc — Abstract Base Classes-Footnote-413959846
Node: atexit — Exit handlers13959953
Ref: library/atexit doc13960133
Ref: 469013960133
Ref: library/atexit atexit-exit-handlers13960133
Ref: 469113960133
Ref: library/atexit module-atexit13960133
Ref: c13960133
Ref: library/atexit translation-repo13960133
Ref: 469213960133
Ref: library/atexit atexit register13961142
Ref: 88513961142
Ref: library/atexit atexit unregister13962744
Ref: 15ca13962744
Node: atexit Example13963419
Ref: library/atexit atexit-example13963494
Ref: 469313963494
Ref: library/atexit id113963494
Ref: 469413963494
Node: traceback — Print or retrieve a stack traceback13964857
Ref: library/traceback doc13965051
Ref: 469513965051
Ref: library/traceback module-traceback13965051
Ref: fe13965051
Ref: library/traceback traceback-print-or-retrieve-a-stack-traceback13965051
Ref: 469613965051
Ref: library/traceback translation-repo13965051
Ref: 469713965051
Ref: traceback — Print or retrieve a stack traceback-Footnote-113967059
Node: Module-Level Functions<2>13967128
Ref: library/traceback module-level-functions13967274
Ref: 469813967274
Ref: library/traceback traceback print_tb13967341
Ref: eb913967341
Ref: library/traceback traceback print_exception13968288
Ref: 85513968288
Ref: library/traceback traceback print_exc13969809
Ref: 19c813969809
Ref: library/traceback traceback print_last13969992
Ref: 469913969992
Ref: library/traceback traceback print_stack13970298
Ref: eba13970298
Ref: library/traceback traceback extract_tb13970860
Ref: 469a13970860
Ref: library/traceback traceback extract_stack13971509
Ref: 469f13971509
Ref: library/traceback traceback print_list13971822
Ref: 46a013971822
Ref: library/traceback traceback format_list13972125
Ref: 46a113972125
Ref: library/traceback traceback format_exception_only13972634
Ref: 85413972634
Ref: library/traceback traceback format_exception13974017
Ref: 85313974017
Ref: library/traceback traceback format_exc13974752
Ref: 46a213974752
Ref: library/traceback traceback format_tb13974912
Ref: 456813974912
Ref: library/traceback traceback format_stack13975028
Ref: 46a313975028
Ref: library/traceback traceback clear_frames13975153
Ref: 100f13975153
Ref: library/traceback traceback walk_stack13975398
Ref: eb513975398
Ref: library/traceback traceback walk_tb13975716
Ref: eb613975716
Node: TracebackException Objects13975958
Ref: library/traceback tracebackexception-objects13976133
Ref: 46a513976133
Ref: library/traceback traceback TracebackException13976616
Ref: 25c13976616
Ref: library/traceback traceback TracebackException __cause__13977922
Ref: 46a713977922
Ref: library/traceback traceback TracebackException __context__13978030
Ref: 46a613978030
Ref: library/traceback traceback TracebackException exceptions13978152
Ref: 46a913978152
Ref: library/traceback traceback TracebackException __suppress_context__13978431
Ref: 46a813978431
Ref: library/traceback traceback TracebackException __notes__13978567
Ref: 46aa13978567
Ref: library/traceback traceback TracebackException stack13978877
Ref: 46ab13978877
Ref: library/traceback traceback TracebackException exc_type13978970
Ref: 25d13978970
Ref: library/traceback traceback TracebackException exc_type_str13979090
Ref: 25b13979090
Ref: library/traceback traceback TracebackException filename13979224
Ref: 46ac13979224
Ref: library/traceback traceback TracebackException lineno13979325
Ref: 46ad13979325
Ref: library/traceback traceback TracebackException end_lineno13979426
Ref: 46ae13979426
Ref: library/traceback traceback TracebackException text13979614
Ref: 46af13979614
Ref: library/traceback traceback TracebackException offset13979706
Ref: 46b013979706
Ref: library/traceback traceback TracebackException end_offset13979826
Ref: 46b113979826
Ref: library/traceback traceback TracebackException msg13980023
Ref: 46b213980023
Ref: library/traceback traceback TracebackException from_exception13980107
Ref: 46b313980107
Ref: library/traceback traceback TracebackException print13980490
Ref: 6a713980490
Ref: library/traceback traceback TracebackException format13980698
Ref: 46b413980698
Ref: library/traceback traceback TracebackException format_exception_only13981149
Ref: 25e13981149
Node: StackSummary Objects13982187
Ref: library/traceback stacksummary-objects13982357
Ref: 46b513982357
Ref: library/traceback traceback StackSummary13982524
Ref: eb713982524
Ref: library/traceback traceback StackSummary extract13982559
Ref: 46a413982559
Ref: library/traceback traceback StackSummary from_list13983551
Ref: 46b613983551
Ref: library/traceback traceback StackSummary format13983855
Ref: 46b713983855
Ref: library/traceback traceback StackSummary format_frame_summary13984487
Ref: 6a613984487
Node: FrameSummary Objects13984891
Ref: library/traceback framesummary-objects13985079
Ref: 46b813985079
Ref: library/traceback traceback FrameSummary13985267
Ref: eb813985267
Ref: library/traceback traceback FrameSummary filename13986177
Ref: 469b13986177
Ref: library/traceback traceback FrameSummary lineno13986380
Ref: 469c13986380
Ref: library/traceback traceback FrameSummary name13986470
Ref: 469d13986470
Ref: library/traceback traceback FrameSummary line13986606
Ref: 469e13986606
Ref: library/traceback traceback FrameSummary end_lineno13986815
Ref: 46b913986815
Ref: library/traceback traceback FrameSummary colno13987098
Ref: 46ba13987098
Ref: library/traceback traceback FrameSummary end_colno13987259
Ref: 46bb13987259
Node: Examples of Using the Module-Level Functions13987429
Ref: library/traceback examples-of-using-the-module-level-functions13987633
Ref: 46bc13987633
Ref: library/traceback traceback-example13987633
Ref: 46bd13987633
Node: Examples of Using TracebackException13993078
Ref: library/traceback examples-of-using-tracebackexception13993253
Ref: 46be13993253
Node: __future__ — Future statement definitions13995909
Ref: library/__future__ doc13996113
Ref: 46bf13996113
Ref: library/__future__ future-future-statement-definitions13996113
Ref: 46c013996113
Ref: library/__future__ module-__future__13996113
Ref: 013996113
Ref: library/__future__ translation-repo13996113
Ref: 46c113996113
Ref: __future__ — Future statement definitions-Footnote-113997639
Node: Module Contents<4>13997709
Ref: library/__future__ module-contents13997807
Ref: 46c213997807
Ref: library/__future__ future__ nested_scopes13998459
Ref: 46c313998459
Ref: library/__future__ future__ generators13998860
Ref: 46c413998860
Ref: library/__future__ future__ division13999254
Ref: 46c513999254
Ref: library/__future__ future__ absolute_import13999661
Ref: 46c613999661
Ref: library/__future__ future__ with_statement14000169
Ref: 46c714000169
Ref: library/__future__ future__ print_function14000570
Ref: 46c814000570
Ref: library/__future__ future__ unicode_literals14000969
Ref: 46c914000969
Ref: library/__future__ future__ generator_stop14001376
Ref: 46ca14001376
Ref: library/__future__ future__ annotations14001793
Ref: 46cb14001793
Ref: library/__future__ future-classes14002107
Ref: 46cc14002107
Ref: library/__future__ future__ _Feature14002107
Ref: 232014002107
Ref: library/__future__ future__ _Feature getOptionalRelease14002754
Ref: 46cd14002754
Ref: library/__future__ future__ _Feature getMandatoryRelease14002888
Ref: 46ce14002888
Ref: library/__future__ future__ _Feature compiler_flag14003476
Ref: 20fb14003476
Ref: Module Contents<4>-Footnote-114004054
Ref: Module Contents<4>-Footnote-214004096
Ref: Module Contents<4>-Footnote-314004138
Ref: Module Contents<4>-Footnote-414004180
Ref: Module Contents<4>-Footnote-514004222
Ref: Module Contents<4>-Footnote-614004264
Ref: Module Contents<4>-Footnote-714004306
Ref: Module Contents<4>-Footnote-814004348
Ref: Module Contents<4>-Footnote-914004390
Ref: Module Contents<4>-Footnote-1014004976
Ref: Module Contents<4>-Footnote-1114005019
Node: gc — Garbage Collector interface14005062
Ref: library/gc doc14005249
Ref: 46cf14005249
Ref: library/gc gc-garbage-collector-interface14005249
Ref: 46d014005249
Ref: library/gc module-gc14005249
Ref: 6014005249
Ref: library/gc translation-repo14005249
Ref: 46d114005249
Ref: library/gc gc enable14006171
Ref: 46d214006171
Ref: library/gc gc disable14006242
Ref: 46d314006242
Ref: library/gc gc isenabled14006315
Ref: 46d414006315
Ref: library/gc gc collect14006406
Ref: a4714006406
Ref: library/gc gc set_debug14007179
Ref: 46d514007179
Ref: library/gc gc get_debug14007446
Ref: 46d614007446
Ref: library/gc gc get_objects14007525
Ref: 80914007525
Ref: library/gc gc get_stats14007948
Ref: f7c14007948
Ref: library/gc gc set_threshold14008645
Ref: 46d714008645
Ref: library/gc gc get_count14009871
Ref: 46d814009871
Ref: library/gc gc get_threshold14009996
Ref: 46d914009996
Ref: library/gc gc get_referrers14010141
Ref: 80a14010141
Ref: library/gc gc get_referents14011153
Ref: 80b14011153
Ref: library/gc gc is_tracked14011880
Ref: 135714011880
Ref: library/gc gc is_finalized14012707
Ref: 90614012707
Ref: library/gc gc freeze14013219
Ref: b5214013219
Ref: library/gc gc unfreeze14014058
Ref: b5314014058
Ref: library/gc gc get_freeze_count14014219
Ref: b5414014219
Ref: library/gc gc garbage14014464
Ref: 120614014464
Ref: library/gc gc callbacks14015333
Ref: 110b14015333
Ref: library/gc gc DEBUG_STATS14016668
Ref: 46db14016668
Ref: library/gc gc DEBUG_COLLECTABLE14016811
Ref: 46dc14016811
Ref: library/gc gc DEBUG_UNCOLLECTABLE14016897
Ref: 120714016897
Ref: library/gc gc DEBUG_SAVEALL14017278
Ref: 46da14017278
Ref: library/gc gc DEBUG_LEAK14017470
Ref: 46dd14017470
Ref: gc — Garbage Collector interface-Footnote-114017714
Ref: gc — Garbage Collector interface-Footnote-214017870
Node: inspect — Inspect live objects14017912
Ref: library/inspect doc14018097
Ref: 46de14018097
Ref: library/inspect inspect-inspect-live-objects14018097
Ref: 46df14018097
Ref: library/inspect translation-repo14018097
Ref: 46e014018097
Ref: library/inspect module-inspect14018186
Ref: 7e14018186
Ref: inspect — Inspect live objects-Footnote-114019379
Node: Types and members14019446
Ref: library/inspect inspect-types14019563
Ref: 1b3a14019563
Ref: library/inspect types-and-members14019563
Ref: 46e114019563
Ref: library/inspect inspect getmembers14037315
Ref: 199514037315
Ref: library/inspect inspect getmembers_static14037921
Ref: 64c14037921
Ref: library/inspect inspect getmodulename14038645
Ref: d6114038645
Ref: library/inspect inspect ismodule14039322
Ref: 46e314039322
Ref: library/inspect inspect isclass14039414
Ref: 46e414039414
Ref: library/inspect inspect ismethod14039553
Ref: 46e514039553
Ref: library/inspect inspect isfunction14039669
Ref: 46e614039669
Ref: library/inspect inspect isgeneratorfunction14039847
Ref: 190114039847
Ref: library/inspect inspect isgenerator14040318
Ref: 46e714040318
Ref: library/inspect inspect iscoroutinefunction14040416
Ref: 2e414040416
Ref: library/inspect inspect markcoroutinefunction14041255
Ref: 49314041255
Ref: library/inspect inspect iscoroutine14041846
Ref: e4814041846
Ref: library/inspect inspect isawaitable14042034
Ref: e4914042034
Ref: library/inspect inspect isasyncgenfunction14042510
Ref: 190214042510
Ref: library/inspect inspect isasyncgen14043220
Ref: 46e814043220
Ref: library/inspect inspect istraceback14043450
Ref: 46e914043450
Ref: library/inspect inspect isframe14043548
Ref: 46ea14043548
Ref: library/inspect inspect iscode14043638
Ref: 46eb14043638
Ref: library/inspect inspect isbuiltin14043726
Ref: 46ec14043726
Ref: library/inspect inspect ismethodwrapper14043862
Ref: 64d14043862
Ref: library/inspect inspect isroutine14044167
Ref: 16f414044167
Ref: library/inspect inspect isabstract14044302
Ref: 46ed14044302
Ref: library/inspect inspect ismethoddescriptor14044410
Ref: 16f314044410
Ref: library/inspect inspect isdatadescriptor14045612
Ref: 46ee14045612
Ref: library/inspect inspect isgetsetdescriptor14046242
Ref: 46ef14046242
Ref: library/inspect inspect ismemberdescriptor14046593
Ref: 46f014046593
Node: Retrieving source code14046955
Ref: library/inspect inspect-source14047130
Ref: 46f114047130
Ref: library/inspect retrieving-source-code14047130
Ref: 46f214047130
Ref: library/inspect inspect getdoc14047197
Ref: a0514047197
Ref: library/inspect inspect getcomments14047705
Ref: 16ce14047705
Ref: library/inspect inspect getfile14048129
Ref: 1c3614048129
Ref: library/inspect inspect getmodule14048363
Ref: 191314048363
Ref: library/inspect inspect getsourcefile14048523
Ref: 191414048523
Ref: library/inspect inspect getsourcelines14048824
Ref: 15fc14048824
Ref: library/inspect inspect getsource14049540
Ref: 161914049540
Ref: library/inspect inspect cleandoc14050092
Ref: 17c514050092
Node: Introspecting callables with the Signature object14050503
Ref: library/inspect inspect-signature-object14050685
Ref: 46f314050685
Ref: library/inspect introspecting-callables-with-the-signature-object14050685
Ref: 46f414050685
Ref: library/inspect inspect signature14051016
Ref: 73b14051016
Ref: library/inspect inspect Signature14053568
Ref: 1cf14053568
Ref: library/inspect inspect Signature empty14054683
Ref: 46f714054683
Ref: library/inspect inspect Signature parameters14054803
Ref: 46f514054803
Ref: library/inspect inspect Signature return_annotation14055298
Ref: 46f814055298
Ref: library/inspect inspect Signature bind14055517
Ref: 166714055517
Ref: library/inspect inspect Signature bind_partial14055795
Ref: 46f914055795
Ref: library/inspect inspect Signature replace14056172
Ref: 46f614056172
Ref: library/inspect inspect Signature format14057027
Ref: 46fa14057027
Ref: library/inspect inspect Signature from_callable14057425
Ref: 73d14057425
Ref: library/inspect inspect Parameter14058129
Ref: 1d014058129
Ref: library/inspect inspect Parameter empty14058541
Ref: 46fc14058541
Ref: library/inspect inspect Parameter name14058672
Ref: 46fd14058672
Ref: library/inspect inspect Parameter default14059140
Ref: 46fe14059140
Ref: library/inspect inspect Parameter annotation14059331
Ref: 46ff14059331
Ref: library/inspect inspect Parameter kind14059519
Ref: 470014059519
Ref: library/inspect inspect Parameter kind description14062417
Ref: 470114062417
Ref: library/inspect inspect Parameter replace14062967
Ref: 46fb14062967
Ref: library/inspect inspect BoundArguments14064083
Ref: 10a714064083
Ref: library/inspect inspect BoundArguments arguments14064287
Ref: 91514064287
Ref: library/inspect inspect BoundArguments args14065136
Ref: 470214065136
Ref: library/inspect inspect BoundArguments kwargs14065287
Ref: 470314065287
Ref: library/inspect inspect BoundArguments signature14065532
Ref: 470414065532
Ref: library/inspect inspect BoundArguments apply_defaults14065630
Ref: e4714065630
Ref: Introspecting callables with the Signature object-Footnote-114066609
Node: Classes and functions<2>14066651
Ref: library/inspect classes-and-functions14066832
Ref: 470514066832
Ref: library/inspect inspect-classes-functions14066832
Ref: 470614066832
Ref: library/inspect inspect getclasstree14066897
Ref: 470714066897
Ref: library/inspect inspect getfullargspec14067476
Ref: 73c14067476
Ref: library/inspect inspect getargvalues14069844
Ref: ef314069844
Ref: library/inspect inspect formatargvalues14070349
Ref: ef414070349
Ref: library/inspect inspect getmro14070819
Ref: 470814070819
Ref: library/inspect inspect getcallargs14071183
Ref: ef214071183
Ref: library/inspect inspect getclosurevars14072548
Ref: 111914072548
Ref: library/inspect inspect unwrap14073266
Ref: f9514073266
Ref: library/inspect inspect get_annotations14074002
Ref: 81914074002
Node: The interpreter stack14076891
Ref: library/inspect inspect-stack14077053
Ref: 470914077053
Ref: library/inspect the-interpreter-stack14077053
Ref: 470a14077053
Ref: library/inspect inspect FrameInfo14077375
Ref: 64f14077375
Ref: library/inspect inspect FrameInfo frame14077405
Ref: 470b14077405
Ref: library/inspect inspect FrameInfo filename14077504
Ref: 470c14077504
Ref: library/inspect inspect FrameInfo lineno14077650
Ref: 470d14077650
Ref: library/inspect inspect FrameInfo function14077816
Ref: 470e14077816
Ref: library/inspect inspect FrameInfo code_context14077949
Ref: 470f14077949
Ref: library/inspect inspect FrameInfo index14078117
Ref: 471014078117
Ref: library/inspect inspect FrameInfo positions14078249
Ref: 471114078249
Ref: library/inspect inspect Traceback14078788
Ref: 65014078788
Ref: library/inspect inspect Traceback filename14078818
Ref: 471314078818
Ref: library/inspect inspect Traceback lineno14078967
Ref: 471414078967
Ref: library/inspect inspect Traceback function14079136
Ref: 471514079136
Ref: library/inspect inspect Traceback code_context14079272
Ref: 471614079272
Ref: library/inspect inspect Traceback index14079443
Ref: 471714079443
Ref: library/inspect inspect Traceback positions14079575
Ref: 471814079575
Ref: library/inspect inspect getframeinfo14081506
Ref: 65214081506
Ref: library/inspect inspect getouterframes14081773
Ref: 65314081773
Ref: library/inspect inspect getinnerframes14082380
Ref: 65414082380
Ref: library/inspect inspect currentframe14082983
Ref: 6e514082983
Ref: library/inspect inspect stack14083384
Ref: 65514083384
Ref: library/inspect inspect trace14083883
Ref: 65614083883
Node: Fetching attributes statically14084471
Ref: library/inspect fetching-attributes-statically14084675
Ref: 471914084675
Ref: library/inspect inspect getattr_static14085257
Ref: 49714085257
Node: Current State of Generators Coroutines and Asynchronous Generators14087064
Ref: library/inspect current-state-of-generators-coroutines-and-asynchronous-generators14087269
Ref: 471a14087269
Ref: library/inspect inspect getgeneratorstate14087751
Ref: 127c14087751
Ref: library/inspect inspect getcoroutinestate14088146
Ref: e4b14088146
Ref: library/inspect inspect getasyncgenstate14088762
Ref: 49514088762
Ref: library/inspect inspect getgeneratorlocals14089634
Ref: 111a14089634
Ref: library/inspect inspect getcoroutinelocals14090511
Ref: e4a14090511
Ref: library/inspect inspect getasyncgenlocals14090749
Ref: 49614090749
Node: Code Objects Bit Flags14091037
Ref: library/inspect code-objects-bit-flags14091224
Ref: 471b14091224
Ref: library/inspect inspect-module-co-flags14091224
Ref: 20fa14091224
Ref: library/inspect inspect CO_OPTIMIZED14091394
Ref: 471c14091394
Ref: library/inspect inspect CO_NEWLOCALS14091481
Ref: 471d14091481
Ref: library/inspect inspect CO_VARARGS14091632
Ref: 471e14091632
Ref: library/inspect inspect CO_VARKEYWORDS14091740
Ref: 471f14091740
Ref: library/inspect inspect CO_NESTED14091852
Ref: 472014091852
Ref: library/inspect inspect CO_GENERATOR14091946
Ref: 472114091946
Ref: library/inspect inspect CO_COROUTINE14092121
Ref: 472214092121
Ref: library/inspect inspect CO_ITERABLE_COROUTINE14092358
Ref: 472314092358
Ref: library/inspect inspect CO_ASYNC_GENERATOR14092673
Ref: 472414092673
Ref: Code Objects Bit Flags-Footnote-114093320
Ref: Code Objects Bit Flags-Footnote-214093362
Ref: Code Objects Bit Flags-Footnote-314093404
Node: Buffer flags14093446
Ref: library/inspect buffer-flags14093592
Ref: 472514093592
Ref: library/inspect inspect BufferFlags14093639
Ref: 46314093639
Ref: library/inspect inspect BufferFlags SIMPLE14093949
Ref: 472714093949
Ref: library/inspect inspect BufferFlags WRITABLE14093977
Ref: 472814093977
Ref: library/inspect inspect BufferFlags FORMAT14094007
Ref: 472914094007
Ref: library/inspect inspect BufferFlags ND14094035
Ref: 472a14094035
Ref: library/inspect inspect BufferFlags STRIDES14094059
Ref: 472b14094059
Ref: library/inspect inspect BufferFlags C_CONTIGUOUS14094088
Ref: 472c14094088
Ref: library/inspect inspect BufferFlags F_CONTIGUOUS14094122
Ref: 472d14094122
Ref: library/inspect inspect BufferFlags ANY_CONTIGUOUS14094156
Ref: 472e14094156
Ref: library/inspect inspect BufferFlags INDIRECT14094192
Ref: 472f14094192
Ref: library/inspect inspect BufferFlags CONTIG14094222
Ref: 473014094222
Ref: library/inspect inspect BufferFlags CONTIG_RO14094250
Ref: 473114094250
Ref: library/inspect inspect BufferFlags STRIDED14094281
Ref: 473214094281
Ref: library/inspect inspect BufferFlags STRIDED_RO14094310
Ref: 473314094310
Ref: library/inspect inspect BufferFlags RECORDS14094342
Ref: 473414094342
Ref: library/inspect inspect BufferFlags RECORDS_RO14094371
Ref: 473514094371
Ref: library/inspect inspect BufferFlags FULL14094403
Ref: 473614094403
Ref: library/inspect inspect BufferFlags FULL_RO14094429
Ref: 473714094429
Ref: library/inspect inspect BufferFlags READ14094458
Ref: 16ba14094458
Ref: library/inspect inspect BufferFlags WRITE14094484
Ref: 16bb14094484
Node: Command-line interface<8>14094540
Ref: library/inspect command-line-interface14094655
Ref: 473814094655
Ref: library/inspect inspect-module-cli14094655
Ref: f9414094655
Ref: library/inspect cmdoption-inspect-details14095032
Ref: 473914095032
Node: site — Site-specific configuration hook14095139
Ref: library/site doc14095281
Ref: 473a14095281
Ref: library/site module-site14095281
Ref: c714095281
Ref: library/site site-site-specific-configuration-hook14095281
Ref: 473b14095281
Ref: library/site translation-repo14095281
Ref: 473c14095281
Ref: site — Site-specific configuration hook-Footnote-114100238
Node: sitecustomize14100302
Ref: library/site module-sitecustomize14100415
Ref: c814100415
Ref: library/site sitecustomize14100415
Ref: 473d14100415
Node: usercustomize14101168
Ref: library/site module-usercustomize14101312
Ref: 10e14101312
Ref: library/site usercustomize14101312
Ref: 473e14101312
Node: Readline configuration14102108
Ref: library/site readline-configuration14102257
Ref: 474014102257
Ref: library/site rlcompleter-config14102257
Ref: 100414102257
Node: Module contents<6>14102932
Ref: library/site module-contents14103093
Ref: 474114103093
Ref: library/site site PREFIXES14103146
Ref: 474214103146
Ref: library/site site ENABLE_USER_SITE14103227
Ref: 473f14103227
Ref: library/site site USER_SITE14103665
Ref: 1edd14103665
Ref: library/site site USER_BASE14104282
Ref: 136614104282
Ref: library/site site main14104842
Ref: 1ede14104842
Ref: library/site site addsitedir14105192
Ref: 201214105192
Ref: library/site site getsitepackages14105414
Ref: 128414105414
Ref: library/site site getuserbase14105550
Ref: 128514105550
Ref: library/site site getusersitepackages14105797
Ref: 128614105797
Node: Command-line interface<9>14106199
Ref: library/site command-line-interface14106329
Ref: 474314106329
Ref: library/site site-commandline14106329
Ref: 474414106329
Ref: library/site cmdoption-site-user-base14106872
Ref: 474514106872
Ref: library/site cmdoption-site-user-site14106946
Ref: 474614106946
Ref: Command-line interface<9>-Footnote-114107680
Node: Custom Python Interpreters14107722
Ref: library/custominterp doc14107870
Ref: 474714107870
Ref: library/custominterp custom-python-interpreters14107870
Ref: 474814107870
Ref: library/custominterp custominterp14107870
Ref: 474914107870
Ref: library/custominterp translation-repo14107870
Ref: 474a14107870
Node: code — Interpreter base classes14108455
Ref: library/code doc14108590
Ref: 474b14108590
Ref: library/code code-interpreter-base-classes14108590
Ref: 474c14108590
Ref: library/code module-code14108590
Ref: 1a14108590
Ref: library/code code InteractiveInterpreter14109008
Ref: 16e114109008
Ref: library/code code InteractiveConsole14109786
Ref: 255214109786
Ref: library/code code interact14110344
Ref: 17e514110344
Ref: library/code code compile_command14111268
Ref: 474f14111268
Ref: code — Interpreter base classes-Footnote-114112554
Node: Interactive Interpreter Objects14112618
Ref: library/code interactive-interpreter-objects14112755
Ref: 475014112755
Ref: library/code interpreter-objects14112755
Ref: 475114112755
Ref: library/code code InteractiveInterpreter runsource14112838
Ref: 475214112838
Ref: library/code code InteractiveInterpreter runcode14114104
Ref: 475414114104
Ref: library/code code InteractiveInterpreter showsyntaxerror14114563
Ref: 475314114563
Ref: library/code code InteractiveInterpreter showtraceback14115037
Ref: dfe14115037
Ref: library/code code InteractiveInterpreter write14115418
Ref: 475514115418
Node: Interactive Console Objects14115638
Ref: library/code console-objects14115775
Ref: 475614115775
Ref: library/code interactive-console-objects14115775
Ref: 475714115775
Ref: library/code code InteractiveConsole interact14116039
Ref: 474e14116039
Ref: library/code code InteractiveConsole push14116892
Ref: 475814116892
Ref: library/code code InteractiveConsole resetbuffer14117600
Ref: 475914117600
Ref: library/code code InteractiveConsole raw_input14117709
Ref: 474d14117709
Node: codeop — Compile Python code14118070
Ref: library/codeop doc14118205
Ref: 475a14118205
Ref: library/codeop codeop-compile-python-code14118205
Ref: 475b14118205
Ref: library/codeop module-codeop14118205
Ref: 1c14118205
Ref: library/codeop translation-repo14118205
Ref: 475c14118205
Ref: library/codeop codeop compile_command14119151
Ref: 18f814119151
Ref: library/codeop codeop Compile14120570
Ref: 475d14120570
Ref: library/codeop codeop CommandCompiler14120970
Ref: 475e14120970
Ref: codeop — Compile Python code-Footnote-114121391
Node: Importing Modules14121457
Ref: library/modules doc14121606
Ref: 475f14121606
Ref: library/modules importing-modules14121606
Ref: 476014121606
Ref: library/modules modules14121606
Ref: 476114121606
Ref: library/modules translation-repo14121606
Ref: 476214121606
Node: zipimport — Import modules from Zip archives14122584
Ref: library/zipimport doc14122730
Ref: 476314122730
Ref: library/zipimport module-zipimport14122730
Ref: 13214122730
Ref: library/zipimport zipimport-import-modules-from-zip-archives14122730
Ref: 476414122730
Ref: library/zipimport zipimport ZipImportError14124921
Ref: 476514124921
Ref: zipimport — Import modules from Zip archives-Footnote-114125203
Ref: zipimport — Import modules from Zip archives-Footnote-214125272
Ref: zipimport — Import modules from Zip archives-Footnote-314125340
Ref: zipimport — Import modules from Zip archives-Footnote-414125382
Ref: zipimport — Import modules from Zip archives-Footnote-514125424
Node: zipimporter Objects14125466
Ref: library/zipimport id114125589
Ref: 476614125589
Ref: library/zipimport zipimporter-objects14125589
Ref: 476714125589
Ref: library/zipimport zipimport zipimporter14125712
Ref: 476814125712
Ref: library/zipimport zipimport zipimporter create_module14126351
Ref: 86514126351
Ref: library/zipimport zipimport zipimporter exec_module14126597
Ref: 31214126597
Ref: library/zipimport zipimport zipimporter find_spec14126756
Ref: 86414126756
Ref: library/zipimport zipimport zipimporter get_code14126938
Ref: 476914126938
Ref: library/zipimport zipimport zipimporter get_data14127119
Ref: 476a14127119
Ref: library/zipimport zipimport zipimporter get_filename14127404
Ref: 476b14127404
Ref: library/zipimport zipimport zipimporter get_source14127669
Ref: 476c14127669
Ref: library/zipimport zipimport zipimporter is_package14127959
Ref: 476d14127959
Ref: library/zipimport zipimport zipimporter load_module14128170
Ref: 31114128170
Ref: library/zipimport zipimport zipimporter invalidate_caches14128534
Ref: 86614128534
Ref: library/zipimport zipimport zipimporter archive14128714
Ref: 476e14128714
Ref: library/zipimport zipimport zipimporter prefix14128847
Ref: 476f14128847
Node: Examples<33>14129247
Ref: library/zipimport examples14129370
Ref: 477014129370
Ref: library/zipimport zipimport-examples14129370
Ref: 477114129370
Node: pkgutil — Package extension utility14130030
Ref: library/pkgutil doc14130231
Ref: 477214130231
Ref: library/pkgutil module-pkgutil14130231
Ref: a914130231
Ref: library/pkgutil pkgutil-package-extension-utility14130231
Ref: 477314130231
Ref: library/pkgutil translation-repo14130231
Ref: 477414130231
Ref: library/pkgutil pkgutil ModuleInfo14130516
Ref: d7514130516
Ref: library/pkgutil pkgutil extend_path14130672
Ref: 16ee14130672
Ref: library/pkgutil pkgutil find_loader14132389
Ref: 2cb14132389
Ref: library/pkgutil pkgutil get_importer14133119
Ref: 477514133119
Ref: library/pkgutil pkgutil get_loader14133635
Ref: 2cc14133635
Ref: library/pkgutil pkgutil iter_importers14134477
Ref: 11dd14134477
Ref: library/pkgutil pkgutil iter_modules14135206
Ref: d7414135206
Ref: library/pkgutil pkgutil walk_packages14136057
Ref: c1f14136057
Ref: library/pkgutil pkgutil get_data14137635
Ref: 477614137635
Ref: library/pkgutil pkgutil resolve_name14139694
Ref: 477914139694
Ref: pkgutil — Package extension utility-Footnote-114141562
Ref: pkgutil — Package extension utility-Footnote-214141629
Ref: pkgutil — Package extension utility-Footnote-314141671
Ref: pkgutil — Package extension utility-Footnote-414141713
Ref: pkgutil — Package extension utility-Footnote-514141755
Ref: pkgutil — Package extension utility-Footnote-614141797
Ref: pkgutil — Package extension utility-Footnote-714141839
Ref: pkgutil — Package extension utility-Footnote-814141881
Ref: pkgutil — Package extension utility-Footnote-914141923
Ref: pkgutil — Package extension utility-Footnote-1014141965
Node: modulefinder — Find modules used by a script14142031
Ref: library/modulefinder doc14142233
Ref: 477a14142233
Ref: library/modulefinder module-modulefinder14142233
Ref: 9114142233
Ref: library/modulefinder modulefinder-find-modules-used-by-a-script14142233
Ref: 477b14142233
Ref: library/modulefinder translation-repo14142233
Ref: 477c14142233
Ref: library/modulefinder modulefinder AddPackagePath14142752
Ref: 477d14142752
Ref: library/modulefinder modulefinder ReplacePackage14142902
Ref: 477e14142902
Ref: library/modulefinder modulefinder ModuleFinder14143065
Ref: 1b9314143065
Ref: library/modulefinder modulefinder ModuleFinder report14143724
Ref: 478014143724
Ref: library/modulefinder modulefinder ModuleFinder run_script14143939
Ref: 477f14143939
Ref: library/modulefinder modulefinder ModuleFinder modules14144077
Ref: 478114144077
Ref: modulefinder — Find modules used by a script-Footnote-114144301
Node: Example usage of ModuleFinder14144373
Ref: library/modulefinder example-usage-of-modulefinder14144485
Ref: 478314144485
Ref: library/modulefinder modulefinder-example14144485
Ref: 478214144485
Node: runpy — Locating and executing Python modules14145858
Ref: library/runpy doc14146065
Ref: 478414146065
Ref: library/runpy module-runpy14146065
Ref: be14146065
Ref: library/runpy runpy-locating-and-executing-python-modules14146065
Ref: 478514146065
Ref: library/runpy translation-repo14146065
Ref: 478614146065
Ref: library/runpy runpy run_module14147084
Ref: 193d14147084
Ref: library/runpy runpy run_path14150505
Ref: 18114150505
Ref: runpy — Locating and executing Python modules-Footnote-114154940
Ref: runpy — Locating and executing Python modules-Footnote-214155005
Ref: runpy — Locating and executing Python modules-Footnote-314155047
Ref: runpy — Locating and executing Python modules-Footnote-414155089
Ref: runpy — Locating and executing Python modules-Footnote-514155131
Ref: runpy — Locating and executing Python modules-Footnote-614155173
Ref: runpy — Locating and executing Python modules-Footnote-714155215
Ref: runpy — Locating and executing Python modules-Footnote-814155257
Node: importlib — The implementation of import14155299
Ref: library/importlib doc14155527
Ref: 478714155527
Ref: library/importlib importlib-the-implementation-of-import14155527
Ref: 478814155527
Ref: library/importlib module-importlib14155527
Ref: 7714155527
Ref: library/importlib translation-repo14155527
Ref: 478914155527
Ref: importlib — The implementation of import-Footnote-114156230
Node: Introduction<12>14156309
Ref: library/importlib introduction14156426
Ref: 478a14156426
Ref: Introduction<12>-Footnote-114158710
Ref: Introduction<12>-Footnote-214158762
Ref: Introduction<12>-Footnote-314158804
Ref: Introduction<12>-Footnote-414158846
Ref: Introduction<12>-Footnote-514158888
Ref: Introduction<12>-Footnote-614158930
Ref: Introduction<12>-Footnote-714158972
Ref: Introduction<12>-Footnote-814159014
Ref: Introduction<12>-Footnote-914159056
Ref: Introduction<12>-Footnote-1014159098
Ref: Introduction<12>-Footnote-1114159141
Ref: Introduction<12>-Footnote-1214159184
Ref: Introduction<12>-Footnote-1314159227
Node: Functions<12>14159270
Ref: library/importlib functions14159453
Ref: 478b14159453
Ref: library/importlib importlib __import__14159492
Ref: 10ab14159492
Ref: library/importlib importlib import_module14159789
Ref: 51b14159789
Ref: library/importlib importlib invalidate_caches14161096
Ref: c3014161096
Ref: library/importlib importlib reload14161729
Ref: 51c14161729
Node: importlib abc – Abstract base classes related to import14165240
Ref: library/importlib importlib-abc-abstract-base-classes-related-to-import14165455
Ref: 478c14165455
Ref: library/importlib module-importlib abc14165455
Ref: 7814165455
Ref: library/importlib importlib abc MetaPathFinder14166243
Ref: 87514166243
Ref: library/importlib importlib abc MetaPathFinder find_spec14166455
Ref: 86f14166455
Ref: library/importlib importlib abc MetaPathFinder invalidate_caches14167200
Ref: 478d14167200
Ref: library/importlib importlib abc PathEntryFinder14167614
Ref: 87614167614
Ref: library/importlib importlib abc PathEntryFinder find_spec14168052
Ref: 87314168052
Ref: library/importlib importlib abc PathEntryFinder invalidate_caches14168691
Ref: 478e14168691
Ref: library/importlib importlib abc Loader14168991
Ref: efb14168991
Ref: library/importlib importlib abc Loader create_module14169418
Ref: cd414169418
Ref: library/importlib importlib abc Loader exec_module14169820
Ref: 87114169820
Ref: library/importlib importlib abc Loader load_module14170290
Ref: 87014170290
Ref: library/importlib importlib abc ResourceLoader14172288
Ref: c0814172288
Ref: library/importlib importlib abc ResourceLoader get_data14172751
Ref: 477714172751
Ref: library/importlib importlib abc InspectLoader14173565
Ref: f8d14173565
Ref: library/importlib importlib abc InspectLoader get_code14173749
Ref: f8e14173749
Ref: library/importlib importlib abc InspectLoader get_source14174332
Ref: f9114174332
Ref: library/importlib importlib abc InspectLoader is_package14174969
Ref: 479014174969
Ref: library/importlib importlib abc InspectLoader source_to_code14175340
Ref: e4314175340
Ref: library/importlib importlib abc InspectLoader exec_module14175986
Ref: 104d14175986
Ref: library/importlib importlib abc InspectLoader load_module14176120
Ref: 479114176120
Ref: library/importlib importlib abc ExecutionLoader14176347
Ref: 479214176347
Ref: library/importlib importlib abc ExecutionLoader get_filename14176594
Ref: 479314176594
Ref: library/importlib importlib abc FileLoader14177181
Ref: 10b114177181
Ref: library/importlib importlib abc FileLoader name14177677
Ref: 479414177677
Ref: library/importlib importlib abc FileLoader path14177760
Ref: 479514177760
Ref: library/importlib importlib abc FileLoader load_module14177829
Ref: 479614177829
Ref: library/importlib importlib abc FileLoader get_filename14178048
Ref: 479714178048
Ref: library/importlib importlib abc FileLoader get_data14178142
Ref: 477814178142
Ref: library/importlib importlib abc SourceLoader14178263
Ref: 479814178263
Ref: library/importlib importlib abc SourceLoader path_stats14179360
Ref: 11ce14179360
Ref: library/importlib importlib abc SourceLoader path_mtime14180140
Ref: 11cd14180140
Ref: library/importlib importlib abc SourceLoader set_data14180689
Ref: 479914180689
Ref: library/importlib importlib abc SourceLoader get_code14181204
Ref: 479a14181204
Ref: library/importlib importlib abc SourceLoader exec_module14181327
Ref: 104e14181327
Ref: library/importlib importlib abc SourceLoader load_module14181470
Ref: 479b14181470
Ref: library/importlib importlib abc SourceLoader get_source14181706
Ref: 105c14181706
Ref: library/importlib importlib abc SourceLoader is_package14181833
Ref: 479c14181833
Ref: library/importlib importlib abc ResourceReader14182236
Ref: b1614182236
Ref: library/importlib importlib abc ResourceReader open_resource14184085
Ref: 479d14184085
Ref: library/importlib importlib abc ResourceReader resource_path14184366
Ref: 479e14184366
Ref: library/importlib importlib abc ResourceReader is_resource14184617
Ref: 479f14184617
Ref: library/importlib importlib abc ResourceReader contents14184847
Ref: 1bd414184847
Ref: library/importlib importlib abc Traversable14185782
Ref: 19cd14185782
Ref: library/importlib importlib abc Traversable name14186222
Ref: 47a014186222
Ref: library/importlib importlib abc Traversable iterdir14186340
Ref: 47a114186340
Ref: library/importlib importlib abc Traversable is_dir14186442
Ref: 47a214186442
Ref: library/importlib importlib abc Traversable is_file14186544
Ref: 47a314186544
Ref: library/importlib importlib abc Traversable joinpath14186642
Ref: 47a414186642
Ref: library/importlib importlib abc Traversable __truediv__14186743
Ref: 47a514186743
Ref: library/importlib importlib abc Traversable open14186853
Ref: 47a614186853
Ref: library/importlib importlib abc Traversable read_bytes14187217
Ref: 47a714187217
Ref: library/importlib importlib abc Traversable read_text14187298
Ref: 47a814187298
Ref: library/importlib importlib abc TraversableResources14187390
Ref: 19cb14187390
Ref: library/importlib importlib abc TraversableResources files14188154
Ref: 47a914188154
Ref: importlib abc – Abstract base classes related to import-Footnote-114188342
Ref: importlib abc – Abstract base classes related to import-Footnote-214188415
Ref: importlib abc – Abstract base classes related to import-Footnote-314188457
Ref: importlib abc – Abstract base classes related to import-Footnote-414188499
Ref: importlib abc – Abstract base classes related to import-Footnote-514188541
Node: importlib machinery – Importers and path hooks14188583
Ref: library/importlib importlib-machinery-importers-and-path-hooks14188830
Ref: 47aa14188830
Ref: library/importlib module-importlib machinery14188830
Ref: 7914188830
Ref: library/importlib importlib machinery SOURCE_SUFFIXES14189161
Ref: 51714189161
Ref: library/importlib importlib machinery DEBUG_BYTECODE_SUFFIXES14189327
Ref: 47ab14189327
Ref: library/importlib importlib machinery OPTIMIZED_BYTECODE_SUFFIXES14189590
Ref: 47ac14189590
Ref: library/importlib importlib machinery BYTECODE_SUFFIXES14189853
Ref: 51914189853
Ref: library/importlib importlib machinery EXTENSION_SUFFIXES14190139
Ref: 51814190139
Ref: library/importlib importlib machinery all_suffixes14190311
Ref: 46e214190311
Ref: library/importlib importlib machinery BuiltinImporter14190747
Ref: cd514190747
Ref: library/importlib importlib machinery FrozenImporter14191312
Ref: 105a14191312
Ref: library/importlib importlib machinery WindowsRegistryFinder14191732
Ref: d5214191732
Ref: library/importlib importlib machinery PathFinder14192220
Ref: 105e14192220
Ref: library/importlib importlib machinery PathFinder find_spec14192535
Ref: 104c14192535
Ref: library/importlib importlib machinery PathFinder invalidate_caches14193705
Ref: c2f14193705
Ref: library/importlib importlib machinery FileFinder14194312
Ref: 10b014194312
Ref: library/importlib importlib machinery FileFinder path14195619
Ref: 47ad14195619
Ref: library/importlib importlib machinery FileFinder find_spec14195692
Ref: efa14195692
Ref: library/importlib importlib machinery FileFinder invalidate_caches14195869
Ref: 47ae14195869
Ref: library/importlib importlib machinery FileFinder path_hook14195949
Ref: 47af14195949
Ref: library/importlib importlib machinery SourceFileLoader14196390
Ref: 10b214196390
Ref: library/importlib importlib machinery SourceFileLoader name14196684
Ref: 47b014196684
Ref: library/importlib importlib machinery SourceFileLoader path14196774
Ref: 47b114196774
Ref: library/importlib importlib machinery SourceFileLoader is_package14196840
Ref: 47b214196840
Ref: library/importlib importlib machinery SourceFileLoader path_stats14196969
Ref: 47b314196969
Ref: library/importlib importlib machinery SourceFileLoader set_data14197106
Ref: 47b414197106
Ref: library/importlib importlib machinery SourceFileLoader load_module14197245
Ref: d5014197245
Ref: library/importlib importlib machinery SourcelessFileLoader14197597
Ref: 10b314197597
Ref: library/importlib importlib machinery SourcelessFileLoader name14198071
Ref: 47b514198071
Ref: library/importlib importlib machinery SourcelessFileLoader path14198155
Ref: 47b614198155
Ref: library/importlib importlib machinery SourcelessFileLoader is_package14198223
Ref: 47b714198223
Ref: library/importlib importlib machinery SourcelessFileLoader get_code14198349
Ref: 47b814198349
Ref: library/importlib importlib machinery SourcelessFileLoader get_source14198485
Ref: 47b914198485
Ref: library/importlib importlib machinery SourcelessFileLoader load_module14198624
Ref: d5114198624
Ref: library/importlib importlib machinery ExtensionFileLoader14198951
Ref: cd614198951
Ref: library/importlib importlib machinery ExtensionFileLoader name14199624
Ref: 47ba14199624
Ref: library/importlib importlib machinery ExtensionFileLoader path14199701
Ref: 47bb14199701
Ref: library/importlib importlib machinery ExtensionFileLoader create_module14199768
Ref: 47bc14199768
Ref: library/importlib importlib machinery ExtensionFileLoader exec_module14199947
Ref: 47bd14199947
Ref: library/importlib importlib machinery ExtensionFileLoader is_package14200107
Ref: 47be14200107
Ref: library/importlib importlib machinery ExtensionFileLoader get_code14200290
Ref: 47bf14200290
Ref: library/importlib importlib machinery ExtensionFileLoader get_source14200399
Ref: 47c014200399
Ref: library/importlib importlib machinery ExtensionFileLoader get_filename14200515
Ref: f9214200515
Ref: library/importlib importlib machinery NamespaceLoader14200627
Ref: f8f14200627
Ref: library/importlib importlib machinery ModuleSpec14201279
Ref: 200d14201279
Ref: library/importlib importlib machinery ModuleSpec name14202080
Ref: 20c714202080
Ref: library/importlib importlib machinery ModuleSpec loader14202290
Ref: 2e314202290
Ref: library/importlib importlib machinery ModuleSpec origin14202493
Ref: 47c114202493
Ref: library/importlib importlib machinery ModuleSpec submodule_search_locations14202982
Ref: 20cb14202982
Ref: library/importlib importlib machinery ModuleSpec loader_state14203632
Ref: 47c214203632
Ref: library/importlib importlib machinery ModuleSpec cached14203876
Ref: 2d614203876
Ref: library/importlib importlib machinery ModuleSpec parent14204174
Ref: 2d814204174
Ref: library/importlib importlib machinery ModuleSpec has_location14204465
Ref: 47c314204465
Ref: library/importlib importlib machinery AppleFrameworkLoader14204752
Ref: 200c14204752
Ref: library/importlib importlib machinery AppleFrameworkLoader name14208050
Ref: 47c414208050
Ref: library/importlib importlib machinery AppleFrameworkLoader path14208127
Ref: 47c514208127
Ref: importlib machinery – Importers and path hooks-Footnote-114208256
Ref: importlib machinery – Importers and path hooks-Footnote-214208336
Ref: importlib machinery – Importers and path hooks-Footnote-314208378
Ref: importlib machinery – Importers and path hooks-Footnote-414208420
Ref: importlib machinery – Importers and path hooks-Footnote-514208462
Node: importlib util – Utility code for importers14208504
Ref: library/importlib importlib-util-utility-code-for-importers14208706
Ref: 47c614208706
Ref: library/importlib module-importlib util14208706
Ref: 7d14208706
Ref: library/importlib importlib util MAGIC_NUMBER14209032
Ref: 51614209032
Ref: library/importlib importlib util cache_from_source14209272
Ref: 2fe14209272
Ref: library/importlib importlib util source_from_cache14211183
Ref: 51d14211183
Ref: library/importlib importlib util decode_source14211810
Ref: f9014211810
Ref: library/importlib importlib util resolve_name14212082
Ref: 91314212082
Ref: library/importlib importlib util find_spec14212978
Ref: 2cd14212978
Ref: library/importlib importlib util module_from_spec14213873
Ref: e4414213873
Ref: library/importlib importlib util spec_from_loader14214508
Ref: 87414214508
Ref: library/importlib importlib util spec_from_file_location14214963
Ref: cd714214963
Ref: library/importlib importlib util source_hash14215446
Ref: b6214215446
Ref: library/importlib importlib util _incompatible_extension_module_restrictions14215713
Ref: 47c714215713
Ref: library/importlib importlib util LazyLoader14216832
Ref: cd314216832
Ref: library/importlib importlib util LazyLoader factory14218316
Ref: 47c814218316
Ref: importlib util – Utility code for importers-Footnote-114218879
Ref: importlib util – Utility code for importers-Footnote-214218953
Ref: importlib util – Utility code for importers-Footnote-314218995
Ref: importlib util – Utility code for importers-Footnote-414219037
Ref: importlib util – Utility code for importers-Footnote-514219079
Ref: importlib util – Utility code for importers-Footnote-614219121
Ref: importlib util – Utility code for importers-Footnote-714219163
Node: Examples<34>14219205
Ref: library/importlib examples14219350
Ref: 47c914219350
Ref: library/importlib importlib-examples14219350
Ref: 47ca14219350
Node: Importing programmatically14219645
Ref: library/importlib importing-programmatically14219765
Ref: 47cb14219765
Node: Checking if a module can be imported14219996
Ref: library/importlib checking-if-a-module-can-be-imported14220157
Ref: 47cc14220157
Node: Importing a source file directly14221070
Ref: library/importlib importing-a-source-file-directly14221230
Ref: 47cd14221230
Node: Implementing lazy imports14222392
Ref: library/importlib implementing-lazy-imports14222538
Ref: 47ce14222538
Node: Setting up an importer14223257
Ref: library/importlib setting-up-an-importer14223408
Ref: 47cf14223408
Node: Approximating importlib import_module14224985
Ref: library/importlib approximating-importlib-import-module14225102
Ref: 47d014225102
Node: importlib resources – Package resource reading opening and access14226602
Ref: library/importlib resources doc14226846
Ref: 47d114226846
Ref: library/importlib resources importlib-resources-package-resource-reading-opening-and-access14226846
Ref: 47d214226846
Ref: library/importlib resources module-importlib resources14226846
Ref: 7b14226846
Ref: library/importlib resources translation-repo14226846
Ref: 47d314226846
Ref: library/importlib resources importlib resources Anchor14228881
Ref: 47d414228881
Ref: library/importlib resources importlib resources files14229079
Ref: 49114229079
Ref: library/importlib resources importlib resources as_file14230120
Ref: 49014230120
Ref: importlib resources – Package resource reading opening and access-Footnote-114230959
Ref: importlib resources – Package resource reading opening and access-Footnote-214231048
Ref: importlib resources – Package resource reading opening and access-Footnote-314231119
Ref: importlib resources – Package resource reading opening and access-Footnote-414231213
Ref: importlib resources – Package resource reading opening and access-Footnote-514231285
Node: Functional API14231362
Ref: library/importlib resources functional-api14231480
Ref: 47d514231480
Ref: library/importlib resources importlib-resources-functional14231480
Ref: 47d614231480
Ref: library/importlib resources importlib resources open_binary14232722
Ref: 1ed14232722
Ref: library/importlib resources importlib resources open_text14233207
Ref: 1ee14233207
Ref: library/importlib resources importlib resources read_binary14234152
Ref: 1f014234152
Ref: library/importlib resources importlib resources read_text14234564
Ref: 1f114234564
Ref: library/importlib resources importlib resources path14235433
Ref: 1ef14235433
Ref: library/importlib resources importlib resources is_resource14236421
Ref: 1ec14236421
Ref: library/importlib resources importlib resources contents14236890
Ref: 1f214236890
Node: importlib resources abc – Abstract base classes for resources14237593
Ref: library/importlib resources abc doc14237844
Ref: 47d714237844
Ref: library/importlib resources abc importlib-resources-abc-abstract-base-classes-for-resources14237844
Ref: 47d814237844
Ref: library/importlib resources abc module-importlib resources abc14237844
Ref: 7c14237844
Ref: library/importlib resources abc translation-repo14237844
Ref: 47d914237844
Ref: library/importlib resources abc importlib resources abc ResourceReader14238135
Ref: 478f14238135
Ref: library/importlib resources abc importlib resources abc ResourceReader open_resource14239933
Ref: 47da14239933
Ref: library/importlib resources abc importlib resources abc ResourceReader resource_path14240194
Ref: 47db14240194
Ref: library/importlib resources abc importlib resources abc ResourceReader is_resource14240430
Ref: 47dc14240430
Ref: library/importlib resources abc importlib resources abc ResourceReader contents14240733
Ref: 47dd14240733
Ref: library/importlib resources abc importlib resources abc Traversable14241602
Ref: 1f314241602
Ref: library/importlib resources abc importlib resources abc Traversable name14241888
Ref: 47de14241888
Ref: library/importlib resources abc importlib resources abc Traversable iterdir14242006
Ref: 47df14242006
Ref: library/importlib resources abc importlib resources abc Traversable is_dir14242096
Ref: 47e014242096
Ref: library/importlib resources abc importlib resources abc Traversable is_file14242192
Ref: 47e114242192
Ref: library/importlib resources abc importlib resources abc Traversable joinpath14242284
Ref: 47e214242284
Ref: library/importlib resources abc importlib resources abc Traversable __truediv__14243398
Ref: 47e314243398
Ref: library/importlib resources abc importlib resources abc Traversable open14243544
Ref: 47e414243544
Ref: library/importlib resources abc importlib resources abc Traversable read_bytes14243908
Ref: 47e514243908
Ref: library/importlib resources abc importlib resources abc Traversable read_text14243983
Ref: 47e614243983
Ref: library/importlib resources abc importlib resources abc TraversableResources14244069
Ref: 2c514244069
Ref: library/importlib resources abc importlib resources abc TraversableResources files14244593
Ref: 47e714244593
Ref: importlib resources abc – Abstract base classes for resources-Footnote-114244781
Node: importlib metadata – Accessing package metadata14244865
Ref: library/importlib metadata doc14245102
Ref: 47e814245102
Ref: library/importlib metadata importlib-metadata-accessing-package-metadata14245102
Ref: 47e914245102
Ref: library/importlib metadata module-importlib metadata14245102
Ref: 7a14245102
Ref: library/importlib metadata translation-repo14245102
Ref: 47ea14245102
Ref: library/importlib metadata using14245102
Ref: 47eb14245102
Ref: importlib metadata – Accessing package metadata-Footnote-114247399
Ref: importlib metadata – Accessing package metadata-Footnote-214247487
Ref: importlib metadata – Accessing package metadata-Footnote-314247571
Ref: importlib metadata – Accessing package metadata-Footnote-414247649
Ref: importlib metadata – Accessing package metadata-Footnote-514247734
Ref: importlib metadata – Accessing package metadata-Footnote-614247819
Ref: importlib metadata – Accessing package metadata-Footnote-714247857
Ref: importlib metadata – Accessing package metadata-Footnote-814247949
Ref: importlib metadata – Accessing package metadata-Footnote-914248018
Node: Overview<3>14248094
Ref: library/importlib metadata overview14248217
Ref: 47ec14248217
Ref: library/importlib metadata importlib metadata PackageNotFoundError14249736
Ref: 47f114249736
Ref: Overview<3>-Footnote-114250029
Node: Functional API<2>14250113
Ref: library/importlib metadata functional-api14250258
Ref: 47f214250258
Node: Entry points14250554
Ref: library/importlib metadata entry-points14250650
Ref: 28414250650
Ref: library/importlib metadata id214250650
Ref: 47f314250650
Ref: library/importlib metadata importlib metadata entry_points14250695
Ref: 47f414250695
Ref: library/importlib metadata importlib metadata EntryPoints14251267
Ref: 47f514251267
Ref: library/importlib metadata importlib metadata EntryPoint14251547
Ref: 47f614251547
Ref: Entry points-Footnote-114254323
Ref: Entry points-Footnote-214254395
Node: Distribution metadata14254463
Ref: library/importlib metadata distribution-metadata14254589
Ref: 47f714254589
Ref: library/importlib metadata metadata14254589
Ref: 47ed14254589
Ref: library/importlib metadata importlib metadata metadata14254652
Ref: 47f814254652
Ref: library/importlib metadata importlib metadata PackageMetadata14254989
Ref: 47f914254989
Ref: Distribution metadata-Footnote-114256258
Ref: Distribution metadata-Footnote-214256363
Ref: Distribution metadata-Footnote-314256447
Ref: Distribution metadata-Footnote-414256489
Node: Distribution versions14256581
Ref: library/importlib metadata distribution-versions14256713
Ref: 47fa14256713
Ref: library/importlib metadata version14256713
Ref: 47ee14256713
Ref: library/importlib metadata importlib metadata version14256776
Ref: 16b714256776
Ref: Distribution versions-Footnote-114257269
Ref: Distribution versions-Footnote-214257355
Node: Distribution files14257439
Ref: library/importlib metadata distribution-files14257575
Ref: 47fb14257575
Ref: library/importlib metadata files14257575
Ref: 47ef14257575
Ref: library/importlib metadata importlib metadata files14257632
Ref: 47fc14257632
Ref: library/importlib metadata importlib metadata PackagePath14258100
Ref: 47fd14258100
Ref: Distribution files-Footnote-114259686
Ref: Distribution files-Footnote-214259770
Node: Distribution requirements14259867
Ref: library/importlib metadata distribution-requirements14260021
Ref: 47fe14260021
Ref: library/importlib metadata requirements14260021
Ref: 47f014260021
Ref: library/importlib metadata importlib metadata requires14260092
Ref: 47ff14260092
Ref: library/importlib metadata package-distributions14260588
Ref: 81614260588
Ref: Distribution requirements-Footnote-114260625
Node: Mapping import to distribution packages14260709
Ref: library/importlib metadata import-distribution-package-mapping14260836
Ref: 480014260836
Ref: library/importlib metadata mapping-import-to-distribution-packages14260836
Ref: 480114260836
Ref: library/importlib metadata importlib metadata packages_distributions14260935
Ref: 480214260935
Ref: Mapping import to distribution packages-Footnote-114261970
Ref: Mapping import to distribution packages-Footnote-214262054
Ref: Mapping import to distribution packages-Footnote-314262132
Node: Distributions14262194
Ref: library/importlib metadata distributions14262350
Ref: 81714262350
Ref: library/importlib metadata id914262350
Ref: 480314262350
Ref: library/importlib metadata importlib metadata distribution14262397
Ref: 480414262397
Ref: library/importlib metadata importlib metadata Distribution14262700
Ref: 480514262700
Ref: Distributions-Footnote-114264321
Ref: Distributions-Footnote-214264405
Ref: Distributions-Footnote-314264447
Node: Distribution Discovery14264539
Ref: library/importlib metadata distribution-discovery14264708
Ref: 480614264708
Ref: Distribution Discovery-Footnote-114265374
Node: Extending the search algorithm14265458
Ref: library/importlib metadata extending-the-search-algorithm14265605
Ref: 480714265605
Ref: Extending the search algorithm-Footnote-114267474
Node: Example<14>14267558
Ref: library/importlib metadata example14267636
Ref: 480814267636
Node: The initialization of the sys path module search path14270930
Ref: library/sys_path_init doc14271095
Ref: 480914271095
Ref: library/sys_path_init sys-path-init14271095
Ref: 1dfe14271095
Ref: library/sys_path_init the-initialization-of-the-sys-path-module-search-path14271095
Ref: 480a14271095
Ref: library/sys_path_init translation-repo14271095
Ref: 480b14271095
Node: Virtual environments<2>14274622
Ref: library/sys_path_init virtual-environments14274754
Ref: 480d14274754
Node: _pth files14275356
Ref: library/sys_path_init pth-files14275512
Ref: 480e14275512
Node: Embedded Python14276661
Ref: library/sys_path_init embedded-python14276785
Ref: 480f14276785
Node: Python Language Services14277228
Ref: library/language doc14277379
Ref: 481014277379
Ref: library/language language14277379
Ref: 481114277379
Ref: library/language python-language-services14277379
Ref: 481214277379
Ref: library/language translation-repo14277379
Ref: 481314277379
Node: ast — Abstract Syntax Trees14278191
Ref: library/ast doc14278343
Ref: 481414278343
Ref: library/ast ast-abstract-syntax-trees14278343
Ref: 481514278343
Ref: library/ast module-ast14278343
Ref: 814278343
Ref: ast — Abstract Syntax Trees-Footnote-114279349
Node: Abstract Grammar14279412
Ref: library/ast abstract-grammar14279515
Ref: 481714279515
Ref: library/ast id114279515
Ref: 481814279515
Node: Node classes14286927
Ref: library/ast node-classes14287050
Ref: 481914287050
Ref: library/ast ast AST14287095
Ref: 1a614287095
Ref: library/ast ast AST _fields14287922
Ref: 160614287922
Ref: library/ast ast AST _field_types14288724
Ref: 1a714288724
Ref: library/ast ast AST lineno14289116
Ref: 481a14289116
Ref: library/ast ast AST col_offset14289143
Ref: 481b14289143
Ref: library/ast ast AST end_lineno14289174
Ref: 481c14289174
Ref: library/ast ast AST end_col_offset14289205
Ref: 481d14289205
Ref: Node classes-Footnote-114293227
Node: Root nodes14293285
Ref: library/ast ast-root-nodes14293364
Ref: 481f14293364
Ref: library/ast root-nodes14293364
Ref: 482014293364
Ref: library/ast ast Module14293405
Ref: 482114293405
Ref: library/ast ast Expression14294083
Ref: 482314294083
Ref: library/ast ast Interactive14294461
Ref: 482514294461
Ref: library/ast ast FunctionType14295187
Ref: 482614295187
Ref: Root nodes-Footnote-114296233
Node: Literals<3>14296275
Ref: library/ast literals14296372
Ref: 482714296372
Ref: library/ast ast Constant14296409
Ref: 2b914296409
Ref: library/ast ast FormattedValue14296933
Ref: 482814296933
Ref: library/ast ast JoinedStr14297788
Ref: 17fb14297788
Ref: library/ast ast List14298763
Ref: 482914298763
Ref: library/ast ast Tuple14298795
Ref: 482a14298795
Ref: library/ast ast Set14299675
Ref: 482c14299675
Ref: library/ast ast Dict14300063
Ref: 1af014300063
Node: Variables14300886
Ref: library/ast variables14300987
Ref: 482d14300987
Ref: library/ast ast Name14301026
Ref: 1ac914301026
Ref: library/ast ast Load14301168
Ref: 1a414301168
Ref: library/ast ast Store14301188
Ref: 482b14301188
Ref: library/ast ast Del14301209
Ref: 482e14301209
Ref: library/ast ast Starred14302074
Ref: 482f14302074
Node: Expressions<2>14302873
Ref: library/ast ast-expressions14302973
Ref: 482414302973
Ref: library/ast expressions14302973
Ref: 483114302973
Ref: library/ast ast Expr14303016
Ref: 483214303016
Ref: library/ast ast UnaryOp14303659
Ref: 481e14303659
Ref: library/ast ast UAdd14303793
Ref: 483614303793
Ref: library/ast ast USub14303813
Ref: 483714303813
Ref: library/ast ast Not14303833
Ref: 483814303833
Ref: library/ast ast Invert14303852
Ref: 483914303852
Ref: library/ast ast BinOp14304189
Ref: 1b5d14304189
Ref: library/ast ast Add14304622
Ref: 483a14304622
Ref: library/ast ast Sub14304641
Ref: 483b14304641
Ref: library/ast ast Mult14304660
Ref: 483c14304660
Ref: library/ast ast Div14304680
Ref: 483d14304680
Ref: library/ast ast FloorDiv14304699
Ref: 483e14304699
Ref: library/ast ast Mod14304723
Ref: 483f14304723
Ref: library/ast ast Pow14304742
Ref: 484014304742
Ref: library/ast ast LShift14304761
Ref: 484114304761
Ref: library/ast ast RShift14304783
Ref: 484214304783
Ref: library/ast ast BitOr14304805
Ref: 484314304805
Ref: library/ast ast BitXor14304826
Ref: 484414304826
Ref: library/ast ast BitAnd14304848
Ref: 484514304848
Ref: library/ast ast MatMult14304870
Ref: 484614304870
Ref: library/ast ast BoolOp14304924
Ref: 484714304924
Ref: library/ast ast And14305585
Ref: 484914305585
Ref: library/ast ast Or14305604
Ref: 484814305604
Ref: library/ast ast Compare14305654
Ref: 484a14305654
Ref: library/ast ast Eq14306300
Ref: 484b14306300
Ref: library/ast ast NotEq14306318
Ref: 484c14306318
Ref: library/ast ast Lt14306339
Ref: 484d14306339
Ref: library/ast ast LtE14306357
Ref: 484e14306357
Ref: library/ast ast Gt14306376
Ref: 484f14306376
Ref: library/ast ast GtE14306394
Ref: 485014306394
Ref: library/ast ast Is14306413
Ref: 485114306413
Ref: library/ast ast IsNot14306431
Ref: 485214306431
Ref: library/ast ast In14306452
Ref: 485314306452
Ref: library/ast ast NotIn14306470
Ref: 485414306470
Ref: library/ast ast Call14306526
Ref: 483014306526
Ref: library/ast ast keyword14307653
Ref: 485614307653
Ref: library/ast ast IfExp14307849
Ref: 485714307849
Ref: library/ast ast Attribute14308332
Ref: 485514308332
Ref: library/ast ast NamedExpr14308921
Ref: 485814308921
Node: Subscripting14309575
Ref: library/ast subscripting14309661
Ref: 485a14309661
Ref: library/ast ast Subscript14309706
Ref: 485b14309706
Ref: library/ast ast Slice14310604
Ref: 485c14310604
Node: Comprehensions14311193
Ref: library/ast comprehensions14311279
Ref: 485d14311279
Ref: library/ast ast ListComp14311328
Ref: 485e14311328
Ref: library/ast ast SetComp14311370
Ref: 485f14311370
Ref: library/ast ast GeneratorExp14311411
Ref: 486014311411
Ref: library/ast ast DictComp14311457
Ref: 486114311457
Ref: library/ast ast comprehension14313381
Ref: 486214313381
Node: Statements14316423
Ref: library/ast ast-statements14316526
Ref: 482214316526
Ref: library/ast statements14316526
Ref: 486314316526
Ref: library/ast ast Assign14316567
Ref: 485914316567
Ref: library/ast ast Assign type_comment14316910
Ref: 486414316910
Ref: library/ast ast AnnAssign14317851
Ref: 486514317851
Ref: library/ast ast AugAssign14320108
Ref: 486614320108
Ref: library/ast ast Raise14320833
Ref: 486714320833
Ref: library/ast ast Assert14321370
Ref: 486814321370
Ref: library/ast ast Delete14321776
Ref: 486914321776
Ref: library/ast ast Pass14322294
Ref: 486a14322294
Ref: library/ast ast TypeAlias14322471
Ref: 17f114322471
Node: Imports14323174
Ref: library/ast imports14323228
Ref: 486c14323228
Ref: library/ast ast Import14323265
Ref: 486d14323265
Ref: library/ast ast ImportFrom14323675
Ref: 486e14323675
Ref: library/ast ast alias14324388
Ref: 1a1b14324388
Node: Control flow14324907
Ref: library/ast control-flow14325012
Ref: 486f14325012
Ref: library/ast ast If14325166
Ref: 487014325166
Ref: library/ast ast For14326416
Ref: 487114326416
Ref: library/ast ast For type_comment14326954
Ref: 487214326954
Ref: library/ast ast While14327679
Ref: 487314327679
Ref: library/ast ast Break14328354
Ref: 487414328354
Ref: library/ast ast Continue14328375
Ref: 487514328375
Ref: library/ast ast Try14329382
Ref: 487614329382
Ref: library/ast ast TryStar14330959
Ref: 487814330959
Ref: library/ast ast ExceptHandler14331965
Ref: 487714331965
Ref: library/ast ast With14333099
Ref: 487914333099
Ref: library/ast ast With type_comment14333330
Ref: 487b14333330
Ref: library/ast ast withitem14333465
Ref: 487a14333465
Node: Pattern matching14334755
Ref: library/ast pattern-matching14334866
Ref: 487c14334866
Ref: library/ast ast Match14334921
Ref: 487d14334921
Ref: library/ast ast match_case14335230
Ref: 487e14335230
Ref: library/ast ast MatchValue14337193
Ref: 487f14337193
Ref: library/ast ast MatchSingleton14338163
Ref: 488014338163
Ref: library/ast ast MatchSequence14339019
Ref: 488114339019
Ref: library/ast ast MatchStar14340210
Ref: 488214340210
Ref: library/ast ast MatchMapping14341819
Ref: 488314341819
Ref: library/ast ast MatchClass14343785
Ref: 488414343785
Ref: library/ast ast MatchAs14346720
Ref: 488514346720
Ref: library/ast ast MatchOr14348338
Ref: 488614348338
Node: Type annotations14349585
Ref: library/ast type-annotations14349699
Ref: 488714349699
Ref: library/ast ast TypeIgnore14349754
Ref: 18b114349754
Node: Type parameters14351000
Ref: library/ast ast-type-params14351128
Ref: 486b14351128
Ref: library/ast type-parameters14351128
Ref: 488814351128
Ref: library/ast ast TypeVar14351261
Ref: 488914351261
Ref: library/ast ast ParamSpec14352452
Ref: 488a14352452
Ref: library/ast ast TypeVarTuple14353826
Ref: 488b14353826
Node: Function and class definitions14355032
Ref: library/ast function-and-class-definitions14355159
Ref: 488c14355159
Ref: library/ast ast FunctionDef14355242
Ref: 181714355242
Ref: library/ast ast FunctionDef type_comment14355851
Ref: 488e14355851
Ref: library/ast ast Lambda14356042
Ref: 483314356042
Ref: library/ast ast arguments14356651
Ref: 488d14356651
Ref: library/ast ast arg14357398
Ref: 488f14357398
Ref: library/ast ast arg type_comment14357614
Ref: 489014357614
Ref: library/ast ast Return14359182
Ref: 489114359182
Ref: library/ast ast Yield14359423
Ref: 483414359423
Ref: library/ast ast YieldFrom14359452
Ref: 483514359452
Ref: library/ast ast Global14360119
Ref: 489214360119
Ref: library/ast ast Nonlocal14360149
Ref: 489314360149
Ref: library/ast ast ClassDef14360798
Ref: 181514360798
Ref: Function and class definitions-Footnote-114362473
Node: Async and await14362515
Ref: library/ast async-and-await14362618
Ref: 489414362618
Ref: library/ast ast AsyncFunctionDef14362671
Ref: 181614362671
Ref: library/ast ast Await14362941
Ref: 489514362941
Ref: library/ast ast AsyncFor14363557
Ref: 489614363557
Ref: library/ast ast AsyncWith14363624
Ref: 489714363624
Node: ast Helpers14364259
Ref: library/ast ast-helpers14364380
Ref: 489814364380
Ref: library/ast ast parse14364566
Ref: 1a814364566
Ref: library/ast ast unparse14367671
Ref: 8ee14367671
Ref: library/ast ast literal_eval14368287
Ref: c3814368287
Ref: library/ast ast get_docstring14370087
Ref: 1bec14370087
Ref: library/ast ast get_source_segment14370548
Ref: 9e314370548
Ref: library/ast ast fix_missing_locations14371030
Ref: 489a14371030
Ref: library/ast ast increment_lineno14371505
Ref: 18b014371505
Ref: library/ast ast copy_location14371737
Ref: 489b14371737
Ref: library/ast ast iter_fields14371996
Ref: 489c14371996
Ref: library/ast ast iter_child_nodes14372151
Ref: 489d14372151
Ref: library/ast ast walk14372329
Ref: 489e14372329
Ref: library/ast ast NodeVisitor14372595
Ref: a7c14372595
Ref: library/ast ast NodeVisitor visit14372937
Ref: 489f14372937
Ref: library/ast ast NodeVisitor generic_visit14373215
Ref: 48a014373215
Ref: library/ast ast NodeVisitor visit_Constant14373529
Ref: a7d14373529
Ref: library/ast ast NodeTransformer14374127
Ref: 48a114374127
Ref: library/ast ast dump14375985
Ref: 8ed14375985
Ref: ast Helpers-Footnote-114378292
Ref: ast Helpers-Footnote-214378334
Ref: ast Helpers-Footnote-314378376
Node: Compiler Flags14378418
Ref: library/ast ast-compiler-flags14378548
Ref: 231f14378548
Ref: library/ast compiler-flags14378548
Ref: 48a214378548
Ref: library/ast ast PyCF_ALLOW_TOP_LEVEL_AWAIT14378719
Ref: 48a314378719
Ref: library/ast ast PyCF_ONLY_AST14378903
Ref: 481614378903
Ref: library/ast ast PyCF_OPTIMIZED_AST14379034
Ref: 48a414379034
Ref: library/ast ast PyCF_TYPE_COMMENTS14379227
Ref: 489914379227
Ref: Compiler Flags-Footnote-114379456
Ref: Compiler Flags-Footnote-214379498
Node: Command-Line Usage<4>14379540
Ref: library/ast ast-cli14379650
Ref: 48a514379650
Ref: library/ast command-line-usage14379650
Ref: 48a614379650
Ref: library/ast cmdoption-ast-h14379909
Ref: 48a714379909
Ref: library/ast cmdoption-ast-help14379909
Ref: 48a814379909
Ref: library/ast cmdoption-ast-m14379971
Ref: 48a914379971
Ref: library/ast cmdoption-ast-mode14379993
Ref: 48aa14379993
Ref: library/ast cmdoption-ast-no-type-comments14380123
Ref: 48ab14380123
Ref: library/ast cmdoption-ast-a14380190
Ref: 48ac14380190
Ref: library/ast cmdoption-ast-include-attributes14380190
Ref: 48ad14380190
Ref: library/ast cmdoption-ast-i14380294
Ref: 48ae14380294
Ref: library/ast cmdoption-ast-indent14380318
Ref: 48af14380318
Ref: Command-Line Usage<4>-Footnote-114381421
Ref: Command-Line Usage<4>-Footnote-214381469
Ref: Command-Line Usage<4>-Footnote-314381536
Ref: Command-Line Usage<4>-Footnote-414381610
Ref: Command-Line Usage<4>-Footnote-514381649
Node: symtable — Access to the compiler’s symbol tables14381686
Ref: library/symtable doc14381895
Ref: 48b014381895
Ref: library/symtable module-symtable14381895
Ref: d814381895
Ref: library/symtable symtable-access-to-the-compiler-s-symbol-tables14381895
Ref: 48b114381895
Ref: library/symtable translation-repo14381895
Ref: 48b214381895
Ref: symtable — Access to the compiler’s symbol tables-Footnote-114382517
Node: Generating Symbol Tables14382585
Ref: library/symtable generating-symbol-tables14382731
Ref: 48b314382731
Ref: library/symtable symtable symtable14382800
Ref: 1b7d14382800
Node: Examining Symbol Tables14383080
Ref: library/symtable examining-symbol-tables14383256
Ref: 48b514383256
Ref: library/symtable symtable SymbolTableType14383323
Ref: 171614383323
Ref: library/symtable symtable SymbolTableType MODULE14383444
Ref: 48b614383444
Ref: library/symtable symtable SymbolTableType FUNCTION14383533
Ref: 48b714383533
Ref: library/symtable symtable SymbolTableType CLASS14383628
Ref: 48b814383628
Ref: library/symtable symtable SymbolTableType ANNOTATION14383807
Ref: 48b914383807
Ref: library/symtable symtable SymbolTableType TYPE_ALIAS14383951
Ref: 48ba14383951
Ref: library/symtable symtable SymbolTableType TYPE_PARAMETERS14384070
Ref: 48bb14384070
Ref: library/symtable symtable SymbolTableType TYPE_VARIABLE14384238
Ref: 48bc14384238
Ref: library/symtable symtable SymbolTable14384607
Ref: 48b414384607
Ref: library/symtable symtable SymbolTable get_type14384709
Ref: 171714384709
Ref: library/symtable symtable SymbolTable get_id14385375
Ref: 48bd14385375
Ref: library/symtable symtable SymbolTable get_name14385447
Ref: 48be14385447
Ref: library/symtable symtable SymbolTable get_lineno14386093
Ref: 48bf14386093
Ref: library/symtable symtable SymbolTable is_optimized14386218
Ref: 48c014386218
Ref: library/symtable symtable SymbolTable is_nested14386327
Ref: 48c114386327
Ref: library/symtable symtable SymbolTable has_children14386431
Ref: 48c214386431
Ref: library/symtable symtable SymbolTable get_identifiers14386605
Ref: 48c414386605
Ref: library/symtable symtable SymbolTable lookup14386782
Ref: 48c514386782
Ref: library/symtable symtable SymbolTable get_symbols14386905
Ref: 48c614386905
Ref: library/symtable symtable SymbolTable get_children14387030
Ref: 48c314387030
Ref: library/symtable symtable Function14387118
Ref: 48c714387118
Ref: library/symtable symtable Function get_parameters14387248
Ref: 48c814387248
Ref: library/symtable symtable Function get_locals14387369
Ref: 48c914387369
Ref: library/symtable symtable Function get_globals14387472
Ref: 48ca14387472
Ref: library/symtable symtable Function get_nonlocals14387577
Ref: 48cb14387577
Ref: library/symtable symtable Function get_frees14387716
Ref: 48cc14387716
Ref: library/symtable symtable Class14387859
Ref: 48cd14387859
Ref: library/symtable symtable Class get_methods14387972
Ref: 2e514387972
Ref: library/symtable symtable Symbol14389203
Ref: 17de14389203
Ref: library/symtable symtable Symbol get_name14389359
Ref: 48ce14389359
Ref: library/symtable symtable Symbol is_referenced14389428
Ref: 48cf14389428
Ref: library/symtable symtable Symbol is_imported14389528
Ref: 48d014389528
Ref: library/symtable symtable Symbol is_parameter14389651
Ref: 48d114389651
Ref: library/symtable symtable Symbol is_global14389744
Ref: 48d214389744
Ref: library/symtable symtable Symbol is_nonlocal14389829
Ref: 1bbc14389829
Ref: library/symtable symtable Symbol is_declared_global14389918
Ref: 136f14389918
Ref: library/symtable symtable Symbol is_local14390055
Ref: 48d314390055
Ref: library/symtable symtable Symbol is_annotated14390151
Ref: 48d414390151
Ref: library/symtable symtable Symbol is_free14390275
Ref: 48d514390275
Ref: library/symtable symtable Symbol is_assigned14390406
Ref: 48d614390406
Ref: library/symtable symtable Symbol is_namespace14390511
Ref: 48d714390511
Ref: library/symtable symtable Symbol get_namespaces14391153
Ref: 48d814391153
Ref: library/symtable symtable Symbol get_namespace14391248
Ref: 48d914391248
Node: Command-Line Usage<5>14391448
Ref: library/symtable command-line-usage14391591
Ref: 48da14391591
Ref: library/symtable symtable-cli14391591
Ref: 48db14391591
Node: token — Constants used with Python parse trees14391940
Ref: library/token doc14392159
Ref: 48dc14392159
Ref: library/token module-token14392159
Ref: fa14392159
Ref: library/token token-constants-used-with-python-parse-trees14392159
Ref: 48dd14392159
Ref: library/token translation-repo14392159
Ref: 48de14392159
Ref: library/token token tok_name14393115
Ref: 48e314393115
Ref: library/token token ISTERMINAL14393333
Ref: 48e414393333
Ref: library/token token ISNONTERMINAL14393420
Ref: 48e514393420
Ref: library/token token ISEOF14393514
Ref: 48e614393514
Ref: library/token token NAME14393645
Ref: 48e114393645
Ref: library/token token NUMBER14393803
Ref: 48e714393803
Ref: library/token token STRING14393891
Ref: 48e814393891
Ref: library/token token OP14394236
Ref: 48e014394236
Ref: library/token token COMMENT14394539
Ref: 48ea14394539
Ref: library/token token NEWLINE14394657
Ref: 48eb14394657
Ref: library/token token NL14394754
Ref: 48ec14394754
Ref: library/token token INDENT14394985
Ref: 1eb414394985
Ref: library/token token DEDENT14395141
Ref: 48ed14395141
Ref: library/token token FSTRING_START14395295
Ref: 48ee14395295
Ref: library/token token FSTRING_MIDDLE14395568
Ref: 48ef14395568
Ref: library/token token FSTRING_END14395995
Ref: 48f414395995
Ref: library/token token ENDMARKER14396185
Ref: 48f514396185
Ref: library/token token ENCODING14396263
Ref: 48f614396263
Ref: library/token token TYPE_IGNORE14396771
Ref: 48f714396771
Ref: library/token token TYPE_COMMENT14397019
Ref: 48f814397019
Ref: library/token token SOFT_KEYWORD14397249
Ref: 48e214397249
Ref: library/token token ERRORTOKEN14397504
Ref: 48fa14397504
Ref: library/token token-operators-delimiters14397834
Ref: 48e914397834
Ref: library/token token LPAR14398368
Ref: 48fb14398368
Ref: library/token token RPAR14398545
Ref: 48fc14398545
Ref: library/token token LSQB14398722
Ref: 48fd14398722
Ref: library/token token RSQB14398899
Ref: 48fe14398899
Ref: library/token token COLON14399077
Ref: 48f314399077
Ref: library/token token COMMA14399254
Ref: 48ff14399254
Ref: library/token token SEMI14399430
Ref: 490014399430
Ref: library/token token PLUS14399607
Ref: 48df14399607
Ref: library/token token MINUS14399785
Ref: 490114399785
Ref: library/token token STAR14399961
Ref: 490214399961
Ref: library/token token SLASH14400139
Ref: 490314400139
Ref: library/token token VBAR14400315
Ref: 490414400315
Ref: library/token token AMPER14400493
Ref: 490514400493
Ref: library/token token LESS14400669
Ref: 490614400669
Ref: library/token token GREATER14400849
Ref: 490714400849
Ref: library/token token EQUAL14401024
Ref: 490814401024
Ref: library/token token DOT14401199
Ref: 490914401199
Ref: library/token token PERCENT14401380
Ref: 490a14401380
Ref: library/token token LBRACE14401556
Ref: 48f014401556
Ref: library/token token RBRACE14401733
Ref: 48f114401733
Ref: library/token token EQEQUAL14401911
Ref: 490b14401911
Ref: library/token token NOTEQUAL14402090
Ref: 490c14402090
Ref: library/token token LESSEQUAL14402269
Ref: 490d14402269
Ref: library/token token GREATEREQUAL14402450
Ref: 490e14402450
Ref: library/token token TILDE14402621
Ref: 490f14402621
Ref: library/token token CIRCUMFLEX14402803
Ref: 491014402803
Ref: library/token token LEFTSHIFT14402979
Ref: 491114402979
Ref: library/token token RIGHTSHIFT14403158
Ref: 491214403158
Ref: library/token token DOUBLESTAR14403336
Ref: 491314403336
Ref: library/token token PLUSEQUAL14403513
Ref: 491414403513
Ref: library/token token MINEQUAL14403690
Ref: 491514403690
Ref: library/token token STAREQUAL14403869
Ref: 491614403869
Ref: library/token token SLASHEQUAL14404048
Ref: 491714404048
Ref: library/token token PERCENTEQUAL14404228
Ref: 491814404228
Ref: library/token token AMPEREQUAL14404404
Ref: 491914404404
Ref: library/token token VBAREQUAL14404581
Ref: 491a14404581
Ref: library/token token CIRCUMFLEXEQUAL14404765
Ref: 491b14404765
Ref: library/token token LEFTSHIFTEQUAL14404942
Ref: 491c14404942
Ref: library/token token RIGHTSHIFTEQUAL14405122
Ref: 491d14405122
Ref: library/token token DOUBLESTAREQUAL14405301
Ref: 491e14405301
Ref: library/token token DOUBLESLASH14405476
Ref: 491f14405476
Ref: library/token token DOUBLESLASHEQUAL14405659
Ref: 492014405659
Ref: library/token token AT14405824
Ref: 492114405824
Ref: library/token token ATEQUAL14406006
Ref: 492214406006
Ref: library/token token RARROW14406183
Ref: 492314406183
Ref: library/token token ELLIPSIS14406363
Ref: 492414406363
Ref: library/token token COLONEQUAL14406544
Ref: 492514406544
Ref: library/token token EXCLAMATION14406723
Ref: 48f214406723
Ref: library/token token N_TOKENS14406867
Ref: 492614406867
Ref: library/token token EXACT_TOKEN_TYPES14406949
Ref: 169a14406949
Ref: token — Constants used with Python parse trees-Footnote-114407872
Node: keyword — Testing for Python keywords14407937
Ref: library/keyword doc14408143
Ref: 492714408143
Ref: library/keyword keyword-testing-for-python-keywords14408143
Ref: 492814408143
Ref: library/keyword module-keyword14408143
Ref: 8414408143
Ref: library/keyword translation-repo14408143
Ref: 492914408143
Ref: library/keyword keyword iskeyword14408462
Ref: 237f14408462
Ref: library/keyword keyword kwlist14408563
Ref: 492a14408563
Ref: library/keyword keyword issoftkeyword14408831
Ref: 48f914408831
Ref: library/keyword keyword softkwlist14408968
Ref: 492b14408968
Ref: keyword — Testing for Python keywords-Footnote-114409313
Node: tokenize — Tokenizer for Python source14409380
Ref: library/tokenize doc14409585
Ref: 492c14409585
Ref: library/tokenize module-tokenize14409585
Ref: fb14409585
Ref: library/tokenize tokenize-tokenizer-for-python-source14409585
Ref: 492d14409585
Ref: library/tokenize translation-repo14409585
Ref: 492e14409585
Ref: tokenize — Tokenizer for Python source-Footnote-114410861
Node: Tokenizing Input14410929
Ref: library/tokenize tokenizing-input14411052
Ref: 492f14411052
Ref: library/tokenize tokenize tokenize14411159
Ref: 4dc14411159
Ref: library/tokenize tokenize generate_tokens14412571
Ref: 4dd14412571
Ref: library/tokenize tokenize untokenize14413320
Ref: 168a14413320
Ref: library/tokenize tokenize detect_encoding14414201
Ref: 2a3514414201
Ref: library/tokenize tokenize open14415183
Ref: 2a3414415183
Ref: library/tokenize tokenize TokenError14415354
Ref: 54514415354
Ref: Tokenizing Input-Footnote-114415670
Ref: Tokenizing Input-Footnote-214415712
Node: Command-Line Usage<6>14415754
Ref: library/tokenize command-line-usage14415898
Ref: 493014415898
Ref: library/tokenize tokenize-cli14415898
Ref: 493114415898
Ref: library/tokenize cmdoption-tokenize-h14416157
Ref: 493214416157
Ref: library/tokenize cmdoption-tokenize-help14416157
Ref: 493314416157
Ref: library/tokenize cmdoption-tokenize-e14416219
Ref: 493414416219
Ref: library/tokenize cmdoption-tokenize-exact14416219
Ref: 493514416219
Node: Examples<35>14416411
Ref: library/tokenize examples14416530
Ref: 493614416530
Node: tabnanny — Detection of ambiguous indentation14421023
Ref: library/tabnanny doc14421229
Ref: 493714421229
Ref: library/tabnanny module-tabnanny14421229
Ref: dd14421229
Ref: library/tabnanny tabnanny-detection-of-ambiguous-indentation14421229
Ref: 493814421229
Ref: library/tabnanny translation-repo14421229
Ref: 493914421229
Ref: library/tabnanny tabnanny check14421760
Ref: 493a14421760
Ref: library/tabnanny tabnanny verbose14422200
Ref: 493b14422200
Ref: library/tabnanny tabnanny filename_only14422357
Ref: 493c14422357
Ref: library/tabnanny tabnanny NannyNag14422575
Ref: 493d14422575
Ref: library/tabnanny tabnanny process_tokens14422740
Ref: 493e14422740
Ref: tabnanny — Detection of ambiguous indentation-Footnote-114423037
Node: pyclbr — Python module browser support14423105
Ref: library/pyclbr doc14423313
Ref: 493f14423313
Ref: library/pyclbr module-pyclbr14423313
Ref: b414423313
Ref: library/pyclbr pyclbr-python-module-browser-support14423313
Ref: 494014423313
Ref: library/pyclbr translation-repo14423313
Ref: 494114423313
Ref: library/pyclbr pyclbr readmodule14424007
Ref: 83114424007
Ref: library/pyclbr pyclbr readmodule_ex14424618
Ref: 83214424618
Ref: pyclbr — Python module browser support-Footnote-114425696
Node: Function Objects14425762
Ref: library/pyclbr function-objects14425880
Ref: 494214425880
Ref: library/pyclbr pyclbr-function-objects14425880
Ref: 494314425880
Ref: library/pyclbr pyclbr Function14425933
Ref: 494414425933
Ref: library/pyclbr pyclbr Function file14426086
Ref: 494514426086
Ref: library/pyclbr pyclbr Function module14426174
Ref: 494614426174
Ref: library/pyclbr pyclbr Function name14426269
Ref: 494714426269
Ref: library/pyclbr pyclbr Function lineno14426332
Ref: 494814426332
Ref: library/pyclbr pyclbr Function parent14426428
Ref: 494914426428
Ref: library/pyclbr pyclbr Function children14426582
Ref: 494a14426582
Ref: library/pyclbr pyclbr Function is_async14426754
Ref: 494b14426754
Node: Class Objects<2>14426939
Ref: library/pyclbr class-objects14427057
Ref: 494c14427057
Ref: library/pyclbr pyclbr-class-objects14427057
Ref: 494d14427057
Ref: library/pyclbr pyclbr Class14427104
Ref: 494e14427104
Ref: library/pyclbr pyclbr Class file14427290
Ref: 494f14427290
Ref: library/pyclbr pyclbr Class module14427375
Ref: 495014427375
Ref: library/pyclbr pyclbr Class name14427467
Ref: 495114427467
Ref: library/pyclbr pyclbr Class lineno14427527
Ref: 495214427527
Ref: library/pyclbr pyclbr Class parent14427623
Ref: 495314427623
Ref: library/pyclbr pyclbr Class children14427773
Ref: 495414427773
Ref: library/pyclbr pyclbr Class super14427933
Ref: 495514427933
Ref: library/pyclbr pyclbr Class methods14428294
Ref: 495614428294
Node: py_compile — Compile Python source files14428522
Ref: library/py_compile doc14428727
Ref: 495714428727
Ref: library/py_compile module-py_compile14428727
Ref: b314428727
Ref: library/py_compile py-compile-compile-python-source-files14428727
Ref: 495814428727
Ref: library/py_compile translation-repo14428727
Ref: 495914428727
Ref: library/py_compile py_compile PyCompileError14429345
Ref: 495a14429345
Ref: library/py_compile py_compile compile14429474
Ref: a3214429474
Ref: library/py_compile py_compile PycInvalidationMode14433214
Ref: 495b14433214
Ref: library/py_compile py_compile PycInvalidationMode TIMESTAMP14433638
Ref: 495d14433638
Ref: library/py_compile py_compile PycInvalidationMode CHECKED_HASH14433920
Ref: 495c14433920
Ref: library/py_compile py_compile PycInvalidationMode UNCHECKED_HASH14434166
Ref: 495e14434166
Ref: py_compile — Compile Python source files-Footnote-114434714
Ref: py_compile — Compile Python source files-Footnote-214434784
Ref: py_compile — Compile Python source files-Footnote-314434826
Ref: py_compile — Compile Python source files-Footnote-414434868
Ref: py_compile — Compile Python source files-Footnote-514434910
Node: Command-Line Interface<5>14434952
Ref: library/py_compile command-line-interface14435056
Ref: 495f14435056
Ref: library/py_compile py-compile-cli14435056
Ref: 496014435056
Ref: library/py_compile cmdoption-python-m-py_compile-arg-file14435485
Ref: 496114435485
Ref: library/py_compile cmdoption-python-m-py_compile14435516
Ref: 496214435516
Ref: library/py_compile cmdoption-python-m-py_compile-q14435668
Ref: 496314435668
Ref: library/py_compile cmdoption-python-m-py_compile-quiet14435668
Ref: 496414435668
Node: compileall — Byte-compile Python libraries14435956
Ref: library/compileall doc14436161
Ref: 496514436161
Ref: library/compileall compileall-byte-compile-python-libraries14436161
Ref: 496614436161
Ref: library/compileall module-compileall14436161
Ref: 2014436161
Ref: library/compileall translation-repo14436161
Ref: 496714436161
Ref: compileall — Byte-compile Python libraries-Footnote-114436982
Node: Command-line use14437052
Ref: library/compileall command-line-use14437174
Ref: 496814437174
Ref: library/compileall compileall-cli14437174
Ref: 496914437174
Ref: library/compileall cmdoption-compileall-arg-directory14437323
Ref: 496a14437323
Ref: library/compileall cmdoption-compileall-arg-file14437349
Ref: 496b14437349
Ref: library/compileall cmdoption-compileall-l14437597
Ref: 496c14437597
Ref: library/compileall cmdoption-compileall-f14437747
Ref: 496d14437747
Ref: library/compileall cmdoption-compileall-q14437818
Ref: 496e14437818
Ref: library/compileall cmdoption-compileall-d14438002
Ref: 496f14438002
Ref: library/compileall cmdoption-compileall-s14438355
Ref: 497014438355
Ref: library/compileall cmdoption-compileall-p14438570
Ref: 497114438570
Ref: library/compileall cmdoption-compileall-x14438790
Ref: 497214438790
Ref: library/compileall cmdoption-compileall-i14438963
Ref: 497314438963
Ref: library/compileall cmdoption-compileall-b14439165
Ref: 497414439165
Ref: library/compileall cmdoption-compileall-r14439491
Ref: 497514439491
Ref: library/compileall cmdoption-compileall-j14439761
Ref: 497614439761
Ref: library/compileall cmdoption-compileall-invalidation-mode14439948
Ref: 497714439948
Ref: library/compileall cmdoption-compileall-o14440747
Ref: 497814440747
Ref: library/compileall cmdoption-compileall-e14440940
Ref: 497914440940
Ref: library/compileall cmdoption-compileall-hardlink-dupes14441020
Ref: 497a14441020
Ref: Command-line use-Footnote-114442303
Node: Public functions14442345
Ref: library/compileall public-functions14442467
Ref: 497b14442467
Ref: library/compileall compileall compile_dir14442520
Ref: b3e14442520
Ref: library/compileall compileall compile_file14446666
Ref: e1114446666
Ref: library/compileall compileall compile_path14449664
Ref: e1214449664
Ref: Public functions-Footnote-114451398
Ref: Public functions-Footnote-214451440
Node: dis — Disassembler for Python bytecode14451482
Ref: library/dis doc14451688
Ref: 497c14451688
Ref: library/dis dis-disassembler-for-python-bytecode14451688
Ref: 497d14451688
Ref: library/dis module-dis14451688
Ref: 3814451688
Ref: library/dis translation-repo14451688
Ref: 497e14451688
Ref: dis — Disassembler for Python bytecode-Footnote-114454404
Node: Command-line interface<10>14454467
Ref: library/dis command-line-interface14454596
Ref: 497f14454596
Ref: library/dis dis-cli14454596
Ref: 498014454596
Ref: library/dis cmdoption-dis-h14454816
Ref: 498114454816
Ref: library/dis cmdoption-dis-help14454816
Ref: 498214454816
Ref: library/dis cmdoption-dis-C14454870
Ref: 498314454870
Ref: library/dis cmdoption-dis-show-caches14454870
Ref: 498414454870
Ref: library/dis cmdoption-dis-O14454956
Ref: 1d814454956
Ref: library/dis cmdoption-dis-show-offsets14454956
Ref: 498514454956
Node: Bytecode analysis14455215
Ref: library/dis bytecode-analysis14455371
Ref: 498614455371
Ref: library/dis dis Bytecode14455613
Ref: f6614455613
Ref: library/dis dis Bytecode from_traceback14457098
Ref: f6814457098
Ref: library/dis dis Bytecode codeobj14457338
Ref: 498714457338
Ref: library/dis dis Bytecode first_line14457399
Ref: 498814457399
Ref: library/dis dis Bytecode dis14457493
Ref: f6714457493
Ref: library/dis dis Bytecode info14457684
Ref: 498914457684
Node: Analysis functions14458233
Ref: library/dis analysis-functions14458391
Ref: 498a14458391
Ref: library/dis dis code_info14458692
Ref: 127f14458692
Ref: library/dis dis show_code14459233
Ref: f6314459233
Ref: library/dis dis dis14459699
Ref: b4c14459699
Ref: library/dis dis distb14461578
Ref: f6414461578
Ref: library/dis dis disassemble14462192
Ref: f6514462192
Ref: library/dis dis get_instructions14463415
Ref: 1d914463415
Ref: library/dis dis findlinestarts14464549
Ref: 498b14464549
Ref: library/dis dis findlabels14465256
Ref: 498c14465256
Ref: library/dis dis stack_effect14465426
Ref: f6914465426
Ref: Analysis functions-Footnote-114466340
Node: Python Bytecode Instructions14466382
Ref: library/dis bytecodes14466541
Ref: 5b514466541
Ref: library/dis python-bytecode-instructions14466541
Ref: 498d14466541
Ref: library/dis dis Instruction14466775
Ref: 1da14466775
Ref: library/dis dis Instruction opcode14466842
Ref: 498e14466842
Ref: library/dis dis Instruction opname14467035
Ref: 499014467035
Ref: library/dis dis Instruction baseopcode14467103
Ref: 499114467103
Ref: library/dis dis Instruction baseopname14467255
Ref: 499214467255
Ref: library/dis dis Instruction arg14467414
Ref: 499414467414
Ref: library/dis dis Instruction oparg14467506
Ref: 499514467506
Ref: library/dis dis Instruction argval14467566
Ref: 499614467566
Ref: library/dis dis Instruction argrepr14467650
Ref: 499714467650
Ref: library/dis dis Instruction offset14467781
Ref: 499814467781
Ref: library/dis dis Instruction start_offset14467865
Ref: 499914467865
Ref: library/dis dis Instruction cache_offset14468076
Ref: 499a14468076
Ref: library/dis dis Instruction end_offset14468173
Ref: 499b14468173
Ref: library/dis dis Instruction starts_line14468266
Ref: 499c14468266
Ref: library/dis dis Instruction line_number14468375
Ref: 499d14468375
Ref: library/dis dis Instruction is_jump_target14468502
Ref: 499e14468502
Ref: library/dis dis Instruction jump_target14468606
Ref: 499f14468606
Ref: library/dis dis Instruction positions14468739
Ref: 49a014468739
Ref: library/dis dis Instruction cache_info14468894
Ref: 49a114468894
Ref: library/dis dis Positions14469603
Ref: 471214469603
Ref: library/dis dis Positions lineno14469715
Ref: 49a214469715
Ref: library/dis dis Positions end_lineno14469738
Ref: 49a314469738
Ref: library/dis dis Positions col_offset14469765
Ref: 49a414469765
Ref: library/dis dis Positions end_col_offset14469792
Ref: 49a514469792
Ref: library/dis opcode-NOP14470156
Ref: 49a614470156
Ref: library/dis opcode-POP_TOP14470288
Ref: 49a714470288
Ref: library/dis opcode-END_FOR14470369
Ref: 49a814470369
Ref: library/dis opcode-END_SEND14470546
Ref: 49a914470546
Ref: library/dis opcode-COPY14470682
Ref: 70c14470682
Ref: library/dis opcode-SWAP14470893
Ref: 70d14470893
Ref: library/dis opcode-CACHE14471054
Ref: 6fc14471054
Ref: library/dis opcode-UNARY_NEGATIVE14471889
Ref: 49aa14471889
Ref: library/dis opcode-UNARY_NOT14471964
Ref: 180014471964
Ref: library/dis opcode-UNARY_INVERT14472138
Ref: 49ab14472138
Ref: library/dis opcode-GET_ITER14472211
Ref: 49ac14472211
Ref: library/dis opcode-GET_YIELD_FROM_ITER14472285
Ref: 49ad14472285
Ref: library/dis opcode-TO_BOOL14472525
Ref: 17fd14472525
Ref: library/dis opcode-BINARY_OP14473042
Ref: 70914473042
Ref: library/dis opcode-BINARY_SUBSCR14473281
Ref: 185114473281
Ref: library/dis opcode-STORE_SUBSCR14473428
Ref: 195114473428
Ref: library/dis opcode-DELETE_SUBSCR14473598
Ref: 49ae14473598
Ref: library/dis opcode-BINARY_SLICE14473735
Ref: 4e214473735
Ref: library/dis opcode-STORE_SLICE14473946
Ref: 4e314473946
Ref: library/dis opcode-GET_AWAITABLE14474201
Ref: 196c14474201
Ref: library/dis opcode-GET_AITER14474827
Ref: 49af14474827
Ref: library/dis opcode-GET_ANEXT14475044
Ref: 49b014475044
Ref: library/dis opcode-END_ASYNC_FOR14475251
Ref: abf14475251
Ref: library/dis opcode-CLEANUP_THROW14475736
Ref: 4e614475736
Ref: library/dis opcode-BEFORE_ASYNC_WITH14476098
Ref: 49b114476098
Ref: library/dis opcode-SET_ADD14476382
Ref: 49b214476382
Ref: library/dis opcode-LIST_APPEND14476534
Ref: 49b314476534
Ref: library/dis opcode-MAP_ADD14476695
Ref: ac114476695
Ref: library/dis opcode-RETURN_VALUE14477303
Ref: 18c314477303
Ref: library/dis opcode-RETURN_CONST14477395
Ref: 4ec14477395
Ref: library/dis opcode-YIELD_VALUE14477533
Ref: 31414477533
Ref: library/dis opcode-SETUP_ANNOTATIONS14477929
Ref: d7e14477929
Ref: library/dis opcode-POP_EXCEPT14478229
Ref: 49b414478229
Ref: library/dis opcode-RERAISE14478451
Ref: 49b514478451
Ref: library/dis opcode-PUSH_EXC_INFO14478809
Ref: 70614478809
Ref: library/dis opcode-CHECK_EXC_MATCH14479049
Ref: 70e14479049
Ref: library/dis opcode-CHECK_EG_MATCH14479311
Ref: 70514479311
Ref: library/dis opcode-WITH_EXCEPT_START14479768
Ref: 49b614479768
Ref: library/dis opcode-LOAD_ASSERTION_ERROR14480304
Ref: 97114480304
Ref: library/dis opcode-LOAD_BUILD_CLASS14480470
Ref: 49b714480470
Ref: library/dis opcode-BEFORE_WITH14480609
Ref: 71014480609
Ref: library/dis opcode-GET_LEN14481032
Ref: 49b814481032
Ref: library/dis opcode-MATCH_MAPPING14481229
Ref: 49b914481229
Ref: library/dis opcode-MATCH_SEQUENCE14481550
Ref: 49ba14481550
Ref: library/dis opcode-MATCH_KEYS14481964
Ref: 71614481964
Ref: library/dis opcode-STORE_NAME14482431
Ref: 49bb14482431
Ref: library/dis opcode-DELETE_NAME14482715
Ref: 49bd14482715
Ref: library/dis opcode-UNPACK_SEQUENCE14482881
Ref: 196e14482881
Ref: library/dis opcode-UNPACK_EX14483173
Ref: 49be14483173
Ref: library/dis opcode-STORE_ATTR14484132
Ref: 196d14484132
Ref: library/dis opcode-DELETE_ATTR14484370
Ref: 49bf14484370
Ref: library/dis opcode-STORE_GLOBAL14484577
Ref: 49bc14484577
Ref: library/dis opcode-DELETE_GLOBAL14484683
Ref: 49c014484683
Ref: library/dis opcode-LOAD_CONST14484785
Ref: 49c114484785
Ref: library/dis opcode-LOAD_NAME14484871
Ref: 49c214484871
Ref: library/dis opcode-LOAD_LOCALS14485067
Ref: 4eb14485067
Ref: library/dis opcode-LOAD_FROM_DICT_OR_GLOBALS14485332
Ref: 4ea14485332
Ref: library/dis opcode-BUILD_TUPLE14485725
Ref: 49c314485725
Ref: library/dis opcode-BUILD_LIST14486051
Ref: 49c414486051
Ref: library/dis opcode-BUILD_SET14486143
Ref: 49c514486143
Ref: library/dis opcode-BUILD_MAP14486233
Ref: 17f214486233
Ref: library/dis opcode-BUILD_CONST_KEY_MAP14486614
Ref: d7b14486614
Ref: library/dis opcode-BUILD_STRING14486936
Ref: d7a14486936
Ref: library/dis opcode-LIST_EXTEND14487101
Ref: 49c614487101
Ref: library/dis opcode-SET_UPDATE14487270
Ref: 49c714487270
Ref: library/dis opcode-DICT_UPDATE14487436
Ref: 49c814487436
Ref: library/dis opcode-DICT_MERGE14487605
Ref: 49c914487605
Ref: library/dis opcode-LOAD_ATTR14487746
Ref: 4e114487746
Ref: library/dis opcode-LOAD_SUPER_ATTR14488683
Ref: 4df14488683
Ref: library/dis opcode-COMPARE_OP14489754
Ref: 97314489754
Ref: library/dis opcode-IS_OP14490133
Ref: 49ca14490133
Ref: library/dis opcode-CONTAINS_OP14490263
Ref: 49cb14490263
Ref: library/dis opcode-IMPORT_NAME14490399
Ref: 49cc14490399
Ref: library/dis opcode-IMPORT_FROM14490819
Ref: 49cd14490819
Ref: library/dis opcode-JUMP_FORWARD14491068
Ref: 16e914491068
Ref: library/dis opcode-JUMP_BACKWARD14491148
Ref: 70f14491148
Ref: library/dis opcode-JUMP_BACKWARD_NO_INTERRUPT14491282
Ref: 70214491282
Ref: library/dis opcode-POP_JUMP_IF_TRUE14491442
Ref: 17fe14491442
Ref: library/dis opcode-POP_JUMP_IF_FALSE14491984
Ref: 17ff14491984
Ref: library/dis opcode-POP_JUMP_IF_NOT_NONE14492529
Ref: 192614492529
Ref: library/dis opcode-POP_JUMP_IF_NONE14492792
Ref: 192514492792
Ref: library/dis opcode-FOR_ITER14493047
Ref: 186614493047
Ref: library/dis opcode-LOAD_GLOBAL14493460
Ref: 17f914493460
Ref: library/dis opcode-LOAD_FAST14493706
Ref: 49ce14493706
Ref: library/dis opcode-LOAD_FAST_LOAD_FAST14494015
Ref: 49cf14494015
Ref: library/dis opcode-LOAD_FAST_CHECK14494206
Ref: 4e814494206
Ref: library/dis opcode-LOAD_FAST_AND_CLEAR14494455
Ref: 4e714494455
Ref: library/dis opcode-STORE_FAST14494753
Ref: 180214494753
Ref: library/dis opcode-STORE_FAST_STORE_FAST14494861
Ref: 49d014494861
Ref: library/dis opcode-STORE_FAST_LOAD_FAST14495067
Ref: 49d114495067
Ref: library/dis opcode-DELETE_FAST14495315
Ref: 49d214495315
Ref: library/dis opcode-MAKE_CELL14495398
Ref: 70314495398
Ref: library/dis opcode-LOAD_DEREF14495572
Ref: 49d314495572
Ref: library/dis opcode-LOAD_FROM_DICT_OR_DEREF14495857
Ref: 4e914495857
Ref: library/dis opcode-STORE_DEREF14496388
Ref: 49d414496388
Ref: library/dis opcode-DELETE_DEREF14496633
Ref: 49d514496633
Ref: library/dis opcode-COPY_FREE_VARS14496926
Ref: 70114496926
Ref: library/dis opcode-RAISE_VARARGS14497174
Ref: 49d614497174
Ref: library/dis opcode-CALL14497643
Ref: 70a14497643
Ref: library/dis opcode-CALL_KW14498415
Ref: 17f314498415
Ref: library/dis opcode-CALL_FUNCTION_EX14499247
Ref: d7d14499247
Ref: library/dis opcode-PUSH_NULL14499929
Ref: 70b14499929
Ref: library/dis opcode-MAKE_FUNCTION14500133
Ref: d7c14500133
Ref: library/dis opcode-SET_FUNCTION_ATTRIBUTE14500610
Ref: 49d714500610
Ref: library/dis opcode-BUILD_SLICE14501325
Ref: 49d814501325
Ref: library/dis opcode-EXTENDED_ARG14501794
Ref: 18c114501794
Ref: library/dis opcode-CONVERT_VALUE14502131
Ref: 49d914502131
Ref: library/dis opcode-FORMAT_SIMPLE14502607
Ref: 49da14502607
Ref: library/dis opcode-FORMAT_WITH_SPEC14502873
Ref: 49db14502873
Ref: library/dis opcode-MATCH_CLASS14503190
Ref: 71514503190
Ref: library/dis opcode-RESUME14503907
Ref: 31514503907
Ref: library/dis opcode-RETURN_GENERATOR14504645
Ref: 6ff14504645
Ref: library/dis opcode-SEND14504939
Ref: 70014504939
Ref: library/dis opcode-HAVE_ARGUMENT14505306
Ref: 48c14505306
Ref: library/dis opcode-CALL_INTRINSIC_114506162
Ref: 4e414506162
Ref: library/dis opcode-CALL_INTRINSIC_214509492
Ref: 4e514509492
Ref: library/dis opcode-SETUP_FINALLY14511535
Ref: 49dc14511535
Ref: library/dis opcode-SETUP_CLEANUP14511799
Ref: 49dd14511799
Ref: library/dis opcode-SETUP_WITH14512204
Ref: 49de14512204
Ref: library/dis opcode-POP_BLOCK14512636
Ref: 49df14512636
Ref: library/dis opcode-JUMP14512789
Ref: 49e014512789
Ref: library/dis opcode-JUMP_NO_INTERRUPT14512807
Ref: 194b14512807
Ref: library/dis opcode-LOAD_CLOSURE14512974
Ref: 17fc14512974
Ref: library/dis opcode-LOAD_METHOD14513269
Ref: c3f14513269
Node: Opcode collections14513403
Ref: library/dis id114513535
Ref: 49e114513535
Ref: library/dis opcode-collections14513535
Ref: 498f14513535
Ref: library/dis dis opname14513889
Ref: 499314513889
Ref: library/dis dis opmap14513976
Ref: 49e214513976
Ref: library/dis dis cmp_op14514052
Ref: 49e314514052
Ref: library/dis dis hasarg14514121
Ref: 29e14514121
Ref: library/dis dis hasconst14514225
Ref: 49e414514225
Ref: library/dis dis hasfree14514301
Ref: 49e514514301
Ref: library/dis dis hasname14514649
Ref: 49e614514649
Ref: library/dis dis hasjump14514734
Ref: 49e714514734
Ref: library/dis dis haslocal14514869
Ref: 49e814514869
Ref: library/dis dis hascompare14514951
Ref: 49e914514951
Ref: library/dis dis hasexc14515028
Ref: 48d14515028
Ref: library/dis dis hasjrel14515138
Ref: 49ea14515138
Ref: library/dis dis hasjabs14515319
Ref: 49eb14515319
Node: pickletools — Tools for pickle developers14515496
Ref: library/pickletools doc14515649
Ref: 49ec14515649
Ref: library/pickletools module-pickletools14515649
Ref: a714515649
Ref: library/pickletools pickletools-tools-for-pickle-developers14515649
Ref: 49ed14515649
Ref: library/pickletools translation-repo14515649
Ref: 49ee14515649
Ref: pickletools — Tools for pickle developers-Footnote-114516403
Node: Command line usage14516474
Ref: library/pickletools command-line-usage14516606
Ref: 49ef14516606
Ref: library/pickletools pickletools-cli14516606
Ref: 49f014516606
Node: Command line options<2>14517561
Ref: library/pickletools command-line-options14517639
Ref: 49f114517639
Ref: library/pickletools cmdoption-pickletools-a14517702
Ref: 49f214517702
Ref: library/pickletools cmdoption-pickletools-annotate14517702
Ref: 49f314517702
Ref: library/pickletools cmdoption-pickletools-o14517788
Ref: 49f414517788
Ref: library/pickletools cmdoption-pickletools-output14517788
Ref: 49f514517788
Ref: library/pickletools cmdoption-pickletools-l14517878
Ref: 49f614517878
Ref: library/pickletools cmdoption-pickletools-indentlevel14517878
Ref: 49f714517878
Ref: library/pickletools cmdoption-pickletools-m14517979
Ref: 49f814517979
Ref: library/pickletools cmdoption-pickletools-memo14517979
Ref: 49f914517979
Ref: library/pickletools cmdoption-pickletools-p14518091
Ref: 49fa14518091
Ref: library/pickletools cmdoption-pickletools-preamble14518091
Ref: 49fb14518091
Node: Programmatic Interface<2>14518233
Ref: library/pickletools programmatic-interface14518365
Ref: 49fc14518365
Ref: library/pickletools pickletools dis14518432
Ref: ce914518432
Ref: library/pickletools pickletools genops14519272
Ref: 49fd14519272
Ref: library/pickletools pickletools optimize14519708
Ref: 2a6b14519708
Node: MS Windows Specific Services14519988
Ref: library/windows doc14520144
Ref: 49fe14520144
Ref: library/windows ms-windows-specific-services14520144
Ref: 49ff14520144
Ref: library/windows mswin-specific-services14520144
Ref: 1fda14520144
Ref: library/windows translation-repo14520144
Ref: 4a0014520144
Node: msvcrt — Useful routines from the MS VC++ runtime14520452
Ref: library/msvcrt doc14520611
Ref: 4a0114520611
Ref: library/msvcrt module-msvcrt14520611
Ref: 9314520611
Ref: library/msvcrt msvcrt-useful-routines-from-the-ms-vc-runtime14520611
Ref: 4a0214520611
Node: File Operations14521664
Ref: library/msvcrt file-operations14521787
Ref: 4a0314521787
Ref: library/msvcrt msvcrt-files14521787
Ref: 4a0414521787
Ref: library/msvcrt msvcrt locking14521838
Ref: 442a14521838
Ref: library/msvcrt msvcrt LK_LOCK14522502
Ref: 4a0514522502
Ref: library/msvcrt msvcrt LK_RLCK14522527
Ref: 4a0614522527
Ref: library/msvcrt msvcrt LK_NBLCK14522768
Ref: 4a0714522768
Ref: library/msvcrt msvcrt LK_NBRLCK14522794
Ref: 4a0814522794
Ref: library/msvcrt msvcrt LK_UNLCK14522923
Ref: 4a0914522923
Ref: library/msvcrt msvcrt setmode14523030
Ref: 4a0a14523030
Ref: library/msvcrt msvcrt open_osfhandle14523269
Ref: 442b14523269
Ref: library/msvcrt msvcrt get_osfhandle14523921
Ref: 442914523921
Node: Console I/O14524181
Ref: library/msvcrt console-i-o14524328
Ref: 4a0b14524328
Ref: library/msvcrt msvcrt-console14524328
Ref: 4a0c14524328
Ref: library/msvcrt msvcrt kbhit14524371
Ref: 4a0d14524371
Ref: library/msvcrt msvcrt getch14524495
Ref: 4a0e14524495
Ref: library/msvcrt msvcrt getwch14524982
Ref: 144314524982
Ref: library/msvcrt msvcrt getche14525094
Ref: 4a0f14525094
Ref: library/msvcrt msvcrt getwche14525241
Ref: 144414525241
Ref: library/msvcrt msvcrt putch14525355
Ref: 4a1014525355
Ref: library/msvcrt msvcrt putwch14525459
Ref: 144514525459
Ref: library/msvcrt msvcrt ungetch14525583
Ref: 4a1114525583
Ref: library/msvcrt msvcrt ungetwch14525798
Ref: 4a1214525798
Node: Other Functions14525926
Ref: library/msvcrt msvcrt-other14526049
Ref: 4a1314526049
Ref: library/msvcrt other-functions14526049
Ref: 4a1414526049
Ref: library/msvcrt msvcrt heapmin14526100
Ref: 4a1514526100
Ref: library/msvcrt msvcrt set_error_mode14526293
Ref: 4a1614526293
Ref: library/msvcrt msvcrt OUT_TO_DEFAULT14526665
Ref: 4a1814526665
Ref: library/msvcrt msvcrt OUT_TO_STDERR14526808
Ref: 4a1914526808
Ref: library/msvcrt msvcrt OUT_TO_MSGBOX14526936
Ref: 4a1a14526936
Ref: library/msvcrt msvcrt REPORT_ERRMODE14527061
Ref: 4a1714527061
Ref: library/msvcrt msvcrt CrtSetReportMode14527195
Ref: 4a1b14527195
Ref: library/msvcrt msvcrt CrtSetReportFile14527583
Ref: 4a1c14527583
Ref: library/msvcrt msvcrt CRT_WARN14527980
Ref: 4a1e14527980
Ref: library/msvcrt msvcrt CRT_ERROR14528095
Ref: 4a1f14528095
Ref: library/msvcrt msvcrt CRT_ASSERT14528211
Ref: 4a2014528211
Ref: library/msvcrt msvcrt CRTDBG_MODE_DEBUG14528266
Ref: 4a2114528266
Ref: library/msvcrt msvcrt CRTDBG_MODE_FILE14528362
Ref: 4a1d14528362
Ref: library/msvcrt msvcrt CRTDBG_MODE_WNDW14528579
Ref: 4a2214528579
Ref: library/msvcrt msvcrt CRTDBG_REPORT_MODE14528737
Ref: 4a2314528737
Ref: library/msvcrt msvcrt CRT_ASSEMBLY_VERSION14528829
Ref: 13ac14528829
Ref: library/msvcrt msvcrt VC_ASSEMBLY_PUBLICKEYTOKEN14528939
Ref: 13ad14528939
Ref: library/msvcrt msvcrt LIBRARIES_ASSEMBLY_NAME_PREFIX14529068
Ref: 13ae14529068
Node: winreg — Windows registry access14529203
Ref: library/winreg doc14529419
Ref: 4a2414529419
Ref: library/winreg module-winreg14529419
Ref: 11614529419
Ref: library/winreg translation-repo14529419
Ref: 4a2514529419
Ref: library/winreg winreg-windows-registry-access14529419
Ref: 4a2614529419
Ref: library/winreg exception-changed14529870
Ref: 4a2814529870
Node: Functions<13>14530111
Ref: library/winreg functions14530217
Ref: 4a2914530217
Ref: library/winreg id114530217
Ref: 4a2a14530217
Ref: library/winreg winreg CloseKey14530301
Ref: 4a2b14530301
Ref: library/winreg winreg ConnectRegistry14530622
Ref: 442f14530622
Ref: library/winreg winreg CreateKey14531314
Ref: 443014531314
Ref: library/winreg winreg CreateKeyEx14532276
Ref: 13af14532276
Ref: library/winreg winreg DeleteKey14533616
Ref: 443114533616
Ref: library/winreg winreg DeleteKeyEx14534365
Ref: 13b014534365
Ref: library/winreg winreg DeleteValue14535644
Ref: 443214535644
Ref: library/winreg winreg EnumKey14536012
Ref: 443314536012
Ref: library/winreg winreg EnumValue14536679
Ref: 443414536679
Ref: library/winreg winreg ExpandEnvironmentStrings14537945
Ref: 144614537945
Ref: library/winreg winreg FlushKey14538296
Ref: 4a3214538296
Ref: library/winreg winreg LoadKey14539081
Ref: 443514539081
Ref: library/winreg winreg OpenKey14540267
Ref: 443614540267
Ref: library/winreg winreg OpenKeyEx14540340
Ref: 4a3514540340
Ref: library/winreg winreg QueryInfoKey14541423
Ref: 443814541423
Ref: library/winreg winreg QueryValue14542319
Ref: 443914542319
Ref: library/winreg winreg QueryValueEx14543196
Ref: 15cf14543196
Ref: library/winreg winreg SaveKey14544072
Ref: 443a14544072
Ref: library/winreg winreg SetValue14545114
Ref: 443b14545114
Ref: library/winreg winreg SetValueEx14546293
Ref: 18a614546293
Ref: library/winreg winreg DisableReflectionKey14547541
Ref: 13b114547541
Ref: library/winreg winreg EnableReflectionKey14548173
Ref: 13b214548173
Ref: library/winreg winreg QueryReflectionKey14548682
Ref: 13b314548682
Ref: Functions<13>-Footnote-114549186
Ref: Functions<13>-Footnote-214549263
Node: Constants<10>14549340
Ref: library/winreg constants14549478
Ref: 4a3a14549478
Ref: library/winreg id214549478
Ref: 4a3b14549478
Node: HKEY_* Constants14549659
Ref: library/winreg hkey-constants14549747
Ref: 4a2d14549747
Ref: library/winreg id314549747
Ref: 4a3c14549747
Ref: library/winreg winreg HKEY_CLASSES_ROOT14549800
Ref: 4a3d14549800
Ref: library/winreg winreg HKEY_CURRENT_USER14550051
Ref: 4a3e14550051
Ref: library/winreg winreg HKEY_LOCAL_MACHINE14550354
Ref: 4a3414550354
Ref: library/winreg winreg HKEY_USERS14550578
Ref: 4a3314550578
Ref: library/winreg winreg HKEY_PERFORMANCE_DATA14550787
Ref: 4a3f14550787
Ref: library/winreg winreg HKEY_CURRENT_CONFIG14551054
Ref: 4a4014551054
Ref: library/winreg winreg HKEY_DYN_DATA14551189
Ref: 4a4114551189
Node: Access Rights14551281
Ref: library/winreg access-rights14551389
Ref: 4a2f14551389
Ref: library/winreg id414551389
Ref: 4a4214551389
Ref: library/winreg winreg KEY_ALL_ACCESS14551500
Ref: 4a4314551500
Ref: library/winreg winreg KEY_WRITE14551789
Ref: 4a2e14551789
Ref: library/winreg winreg KEY_READ14551942
Ref: 4a3614551942
Ref: library/winreg winreg KEY_EXECUTE14552121
Ref: 4a4914552121
Ref: library/winreg winreg KEY_QUERY_VALUE14552193
Ref: 4a4414552193
Ref: library/winreg winreg KEY_SET_VALUE14552281
Ref: 4a3814552281
Ref: library/winreg winreg KEY_CREATE_SUB_KEY14552372
Ref: 4a4514552372
Ref: library/winreg winreg KEY_ENUMERATE_SUB_KEYS14552462
Ref: 4a4614552462
Ref: library/winreg winreg KEY_NOTIFY14552562
Ref: 4a4714552562
Ref: library/winreg winreg KEY_CREATE_LINK14552696
Ref: 4a4814552696
Ref: Access Rights-Footnote-114552827
Node: 64-bit Specific14552904
Ref: library/winreg bit-access-rights14552969
Ref: 4a4a14552969
Ref: library/winreg bit-specific14552969
Ref: 4a4b14552969
Ref: library/winreg winreg KEY_WOW64_64KEY14553088
Ref: 4a3014553088
Ref: library/winreg winreg KEY_WOW64_32KEY14553276
Ref: 4a4c14553276
Ref: 64-bit Specific-Footnote-114553500
Node: Value Types14553572
Ref: library/winreg id514553655
Ref: 4a4d14553655
Ref: library/winreg value-types14553655
Ref: 4a3914553655
Ref: library/winreg winreg REG_BINARY14553750
Ref: 4a4e14553750
Ref: library/winreg winreg REG_DWORD14553810
Ref: 4a4f14553810
Ref: library/winreg winreg REG_DWORD_LITTLE_ENDIAN14553859
Ref: 4a5014553859
Ref: library/winreg winreg REG_DWORD_BIG_ENDIAN14553991
Ref: 4a5114553991
Ref: library/winreg winreg REG_EXPAND_SZ14554074
Ref: 4a3114554074
Ref: library/winreg winreg REG_LINK14554203
Ref: 4a5214554203
Ref: library/winreg winreg REG_MULTI_SZ14554261
Ref: 1b6e14554261
Ref: library/winreg winreg REG_NONE14554427
Ref: 4a5314554427
Ref: library/winreg winreg REG_QWORD14554483
Ref: d2a14554483
Ref: library/winreg winreg REG_QWORD_LITTLE_ENDIAN14554562
Ref: 4a5414554562
Ref: library/winreg winreg REG_RESOURCE_LIST14554721
Ref: 4a5514554721
Ref: library/winreg winreg REG_FULL_RESOURCE_DESCRIPTOR14554794
Ref: 4a5614554794
Ref: library/winreg winreg REG_RESOURCE_REQUIREMENTS_LIST14554867
Ref: 4a5714554867
Ref: library/winreg winreg REG_SZ14554948
Ref: 4a3714554948
Ref: Value Types-Footnote-114555041
Node: Registry Handle Objects14555118
Ref: library/winreg handle-object14555234
Ref: 4a2714555234
Ref: library/winreg registry-handle-objects14555234
Ref: 4a5814555234
Ref: library/winreg winreg PyHKEY Close14556247
Ref: 4a2c14556247
Ref: library/winreg winreg PyHKEY Detach14556379
Ref: 443714556379
Ref: library/winreg winreg PyHKEY __enter__14556978
Ref: 4a5914556978
Ref: library/winreg winreg PyHKEY __exit__14557010
Ref: 4a5a14557010
Node: winsound — Sound-playing interface for Windows14557405
Ref: library/winsound doc14557561
Ref: 4a5b14557561
Ref: library/winsound module-winsound14557561
Ref: 11714557561
Ref: library/winsound translation-repo14557561
Ref: 4a5c14557561
Ref: library/winsound winsound-sound-playing-interface-for-windows14557561
Ref: 4a5d14557561
Ref: library/winsound winsound Beep14557942
Ref: d2c14557942
Ref: library/winsound winsound PlaySound14558330
Ref: d2e14558330
Ref: library/winsound winsound MessageBeep14558902
Ref: d2d14558902
Ref: library/winsound winsound SND_FILENAME14559511
Ref: 4a5e14559511
Ref: library/winsound winsound SND_ALIAS14559644
Ref: 4a5f14559644
Ref: library/winsound winsound SND_LOOP14561262
Ref: 4a6114561262
Ref: library/winsound winsound SND_MEMORY14561449
Ref: 4a6314561449
Ref: library/winsound winsound SND_PURGE14561811
Ref: 4a6414561811
Ref: library/winsound winsound SND_ASYNC14561971
Ref: 4a6214561971
Ref: library/winsound winsound SND_NODEFAULT14562067
Ref: 4a6014562067
Ref: library/winsound winsound SND_NOSTOP14562190
Ref: 4a6514562190
Ref: library/winsound winsound SND_NOWAIT14562270
Ref: 4a6614562270
Ref: library/winsound winsound SND_APPLICATION14562428
Ref: 4a6714562428
Ref: library/winsound winsound MB_ICONASTERISK14562663
Ref: 4a6814562663
Ref: library/winsound winsound MB_ICONEXCLAMATION14562741
Ref: 4a6914562741
Ref: library/winsound winsound MB_ICONHAND14562826
Ref: 4a6a14562826
Ref: library/winsound winsound MB_ICONQUESTION14562897
Ref: 4a6b14562897
Ref: library/winsound winsound MB_OK14562976
Ref: 4a6c14562976
Node: Unix-specific services14563044
Ref: library/unix doc14563210
Ref: 4a6d14563210
Ref: library/unix translation-repo14563210
Ref: 4a6e14563210
Ref: library/unix unix14563210
Ref: 4a6f14563210
Ref: library/unix unix-specific-services14563210
Ref: 4a7014563210
Node: shlex — Simple lexical analysis14563869
Ref: library/shlex doc14564014
Ref: 4a7114564014
Ref: library/shlex module-shlex14564014
Ref: c414564014
Ref: library/shlex shlex-simple-lexical-analysis14564014
Ref: 4a7214564014
Ref: library/shlex shlex split14564530
Ref: 53f14564530
Ref: library/shlex shlex join14565127
Ref: a3414565127
Ref: library/shlex shlex quote14565585
Ref: 27d14565585
Ref: library/shlex shlex-quote-warning14565813
Ref: 342714565813
Ref: library/shlex shlex shlex14567431
Ref: cf314567431
Ref: shlex — Simple lexical analysis-Footnote-114569648
Node: shlex Objects14569713
Ref: library/shlex id114569818
Ref: 4a7614569818
Ref: library/shlex shlex-objects14569818
Ref: 4a7714569818
Ref: library/shlex shlex shlex get_token14569922
Ref: 4a7814569922
Ref: library/shlex shlex shlex push_token14570285
Ref: 4a7914570285
Ref: library/shlex shlex shlex read_token14570367
Ref: 4a7b14570367
Ref: library/shlex shlex shlex sourcehook14570606
Ref: 4a7c14570606
Ref: library/shlex shlex shlex push_source14572145
Ref: 4a7e14572145
Ref: library/shlex shlex shlex pop_source14572448
Ref: 4a7f14572448
Ref: library/shlex shlex shlex error_leader14572647
Ref: 4a8014572647
Ref: library/shlex shlex shlex commenters14573371
Ref: 4a7314573371
Ref: library/shlex shlex shlex wordchars14573593
Ref: 4a7514573593
Ref: library/shlex shlex shlex whitespace14574289
Ref: 4a8214574289
Ref: library/shlex shlex shlex escape14574487
Ref: 4a8314574487
Ref: library/shlex shlex shlex quotes14574652
Ref: 4a8414574652
Ref: library/shlex shlex shlex escapedquotes14574937
Ref: 4a8514574937
Ref: library/shlex shlex shlex whitespace_split14575166
Ref: 4a8114575166
Ref: library/shlex shlex shlex infile14575704
Ref: 4a7414575704
Ref: library/shlex shlex shlex instream14575935
Ref: 4a8614575935
Ref: library/shlex shlex shlex source14576060
Ref: 4a7d14576060
Ref: library/shlex shlex shlex debug14576649
Ref: 4a8714576649
Ref: library/shlex shlex shlex lineno14576913
Ref: 4a8814576913
Ref: library/shlex shlex shlex token14577009
Ref: 4a8914577009
Ref: library/shlex shlex shlex eof14577126
Ref: 4a7a14577126
Ref: library/shlex shlex shlex punctuation_chars14577302
Ref: 1b6114577302
Node: Parsing Rules14577713
Ref: library/shlex parsing-rules14577861
Ref: 4a8a14577861
Ref: library/shlex shlex-parsing-rules14577861
Ref: 4a8b14577861
Node: Improved Compatibility with Shells14579878
Ref: library/shlex improved-compatibility-with-shells14580004
Ref: 4a8c14580004
Ref: library/shlex improved-shell-compatibility14580004
Ref: cf414580004
Node: posix — The most common POSIX system calls14582839
Ref: library/posix doc14583022
Ref: 4a8d14583022
Ref: library/posix module-posix14583022
Ref: ad14583022
Ref: library/posix posix-the-most-common-posix-system-calls14583022
Ref: 4a8e14583022
Ref: library/posix translation-repo14583022
Ref: 4a8f14583022
Node: Large File Support14584221
Ref: library/posix large-file-support14584352
Ref: 4a9014584352
Ref: library/posix posix-large-files14584352
Ref: 4a9114584352
Node: Notable Module Contents14585306
Ref: library/posix notable-module-contents14585437
Ref: 4a9214585437
Ref: library/posix posix-contents14585437
Ref: 4a9314585437
Ref: library/posix posix environ14585633
Ref: 4a9414585633
Node: pwd — The password database14586801
Ref: library/pwd doc14586977
Ref: 4a9514586977
Ref: library/pwd module-pwd14586977
Ref: b214586977
Ref: library/pwd pwd-the-password-database14586977
Ref: 4a9614586977
Ref: library/pwd translation-repo14586977
Ref: 4a9714586977
Ref: library/pwd pwd getpwuid14589145
Ref: 1bc014589145
Ref: library/pwd pwd getpwnam14589251
Ref: 341714589251
Ref: library/pwd pwd getpwall14589352
Ref: 4a9814589352
Node: grp — The group database14589573
Ref: library/grp doc14589740
Ref: 4a9914589740
Ref: library/grp grp-the-group-database14589740
Ref: 4a9a14589740
Ref: library/grp module-grp14589740
Ref: 6614589740
Ref: library/grp translation-repo14589740
Ref: 4a9b14589740
Ref: library/grp grp getgrgid14591350
Ref: d4e14591350
Ref: library/grp grp getgrnam14591652
Ref: 341614591652
Ref: library/grp grp getgrall14591828
Ref: 169d14591828
Node: termios — POSIX style tty control14592031
Ref: library/termios doc14592203
Ref: 4a9c14592203
Ref: library/termios module-termios14592203
Ref: e114592203
Ref: library/termios termios-posix-style-tty-control14592203
Ref: 4a9d14592203
Ref: library/termios translation-repo14592203
Ref: 4a9e14592203
Ref: library/termios termios tcgetattr14593218
Ref: 178914593218
Ref: library/termios termios tcsetattr14593791
Ref: 180814593791
Ref: library/termios termios TCSANOW14594070
Ref: 4a9f14594070
Ref: library/termios termios TCSADRAIN14594144
Ref: 4aa014594144
Ref: library/termios termios TCSAFLUSH14594245
Ref: 4aa114594245
Ref: library/termios termios tcsendbreak14594388
Ref: 4aa214594388
Ref: library/termios termios tcdrain14594602
Ref: 4aa314594602
Ref: library/termios termios tcflush14594725
Ref: 4aa414594725
Ref: library/termios termios tcflow14594983
Ref: 4aa514594983
Ref: library/termios termios tcgetwinsize14595263
Ref: 4aa614595263
Ref: library/termios termios tcsetwinsize14595507
Ref: 4aa714595507
Ref: termios — POSIX style tty control-Footnote-114596116
Node: Example<15>14596163
Ref: library/termios example14596246
Ref: 4aa814596246
Ref: library/termios termios-example14596246
Ref: 4aa914596246
Node: tty — Terminal control functions14597004
Ref: library/tty doc14597183
Ref: 4aaa14597183
Ref: library/tty module-tty14597183
Ref: 10014597183
Ref: library/tty translation-repo14597183
Ref: 4aab14597183
Ref: library/tty tty-terminal-control-functions14597183
Ref: 4aac14597183
Ref: library/tty tty cfmakeraw14597627
Ref: 17dc14597627
Ref: library/tty tty cfmakecbreak14597851
Ref: 178c14597851
Ref: library/tty tty setraw14598419
Ref: 17db14598419
Ref: library/tty tty setcbreak14598903
Ref: 178b14598903
Ref: tty — Terminal control functions-Footnote-114599908
Node: pty — Pseudo-terminal utilities14599971
Ref: library/pty doc14600157
Ref: 4aad14600157
Ref: library/pty module-pty14600157
Ref: b114600157
Ref: library/pty pty-pseudo-terminal-utilities14600157
Ref: 4aae14600157
Ref: library/pty translation-repo14600157
Ref: 4aaf14600157
Ref: library/pty pty fork14600827
Ref: 186c14600827
Ref: library/pty pty openpty14601425
Ref: 2ce14601425
Ref: library/pty pty spawn14601704
Ref: fbb14601704
Ref: pty — Pseudo-terminal utilities-Footnote-114603965
Node: Example<16>14604028
Ref: library/pty example14604109
Ref: 4ab014604109
Ref: Example<16>-Footnote-114605330
Node: fcntl — The fcntl and ioctl system calls14605376
Ref: library/fcntl doc14605567
Ref: 4ab114605567
Ref: library/fcntl fcntl-the-fcntl-and-ioctl-system-calls14605567
Ref: 4ab214605567
Ref: library/fcntl module-fcntl14605567
Ref: 5914605567
Ref: library/fcntl translation-repo14605567
Ref: 4ab314605567
Ref: library/fcntl fcntl fcntl14609024
Ref: 367014609024
Ref: library/fcntl fcntl ioctl14610912
Ref: 14ca14610912
Ref: library/fcntl fcntl flock14613497
Ref: 442814613497
Ref: library/fcntl fcntl lockf14614021
Ref: 143a14614021
Ref: library/fcntl fcntl LOCK_UN14614364
Ref: 4ab414614364
Ref: library/fcntl fcntl LOCK_SH14614431
Ref: 4ab514614431
Ref: library/fcntl fcntl LOCK_EX14614495
Ref: 4ab614614495
Ref: library/fcntl fcntl LOCK_NB14614563
Ref: 4ab714614563
Ref: fcntl — The fcntl and ioctl system calls-Footnote-114616864
Ref: fcntl — The fcntl and ioctl system calls-Footnote-214616909
Ref: fcntl — The fcntl and ioctl system calls-Footnote-314616954
Node: resource — Resource usage information14616999
Ref: library/resource doc14617196
Ref: 4ab814617196
Ref: library/resource module-resource14617196
Ref: bc14617196
Ref: library/resource resource-resource-usage-information14617196
Ref: 4ab914617196
Ref: library/resource translation-repo14617196
Ref: 4aba14617196
Ref: library/resource resource error14617723
Ref: 4abb14617723
Ref: resource — Resource usage information-Footnote-114617997
Node: Resource Limits14618039
Ref: library/resource resource-limits14618153
Ref: 4abc14618153
Ref: library/resource resource RLIM_INFINITY14619033
Ref: 162414619033
Ref: library/resource resource getrlimit14619137
Ref: 162314619137
Ref: library/resource resource setrlimit14619431
Ref: 162514619431
Ref: library/resource resource prlimit14620575
Ref: fc314620575
Ref: library/resource resource RLIMIT_CORE14622165
Ref: 43cb14622165
Ref: library/resource resource RLIMIT_CPU14622426
Ref: 4abe14622426
Ref: library/resource resource RLIMIT_FSIZE14622793
Ref: 4abf14622793
Ref: library/resource resource RLIMIT_DATA14622889
Ref: 4ac014622889
Ref: library/resource resource RLIMIT_STACK14622980
Ref: 4ac114622980
Ref: library/resource resource RLIMIT_RSS14623177
Ref: 4ac214623177
Ref: library/resource resource RLIMIT_NPROC14623295
Ref: 4ac314623295
Ref: library/resource resource RLIMIT_NOFILE14623398
Ref: 4abd14623398
Ref: library/resource resource RLIMIT_OFILE14623512
Ref: 4ac414623512
Ref: library/resource resource RLIMIT_MEMLOCK14623595
Ref: 4ac514623595
Ref: library/resource resource RLIMIT_VMEM14623693
Ref: 4ac614623693
Ref: library/resource resource RLIMIT_AS14623902
Ref: 4ac714623902
Ref: library/resource resource RLIMIT_MSGQUEUE14624023
Ref: fc414624023
Ref: library/resource resource RLIMIT_NICE14624210
Ref: fc514624210
Ref: library/resource resource RLIMIT_RTPRIO14624405
Ref: fc614624405
Ref: library/resource resource RLIMIT_RTTIME14624562
Ref: fc714624562
Ref: library/resource resource RLIMIT_SIGPENDING14624817
Ref: fc814624817
Ref: library/resource resource RLIMIT_SBSIZE14624989
Ref: fc914624989
Ref: library/resource resource RLIMIT_SWAP14625293
Ref: fca14625293
Ref: library/resource resource RLIMIT_NPTS14625676
Ref: fcb14625676
Ref: library/resource resource RLIMIT_KQUEUES14625853
Ref: 1a4c14625853
Ref: Resource Limits-Footnote-114626072
Ref: Resource Limits-Footnote-214626121
Ref: Resource Limits-Footnote-314626170
Node: Resource Usage14626237
Ref: library/resource resource-usage14626351
Ref: 4ac814626351
Ref: library/resource resource getrusage14626466
Ref: 147f14626466
Ref: library/resource resource getpagesize14631013
Ref: 4ac914631013
Ref: library/resource resource RUSAGE_SELF14631318
Ref: 4aca14631318
Ref: library/resource resource RUSAGE_CHILDREN14631519
Ref: 4acb14631519
Ref: library/resource resource RUSAGE_BOTH14631719
Ref: 4acc14631719
Ref: library/resource resource RUSAGE_THREAD14631917
Ref: 4acd14631917
Ref: Resource Usage-Footnote-114632150
Node: syslog — Unix syslog library routines14632199
Ref: library/syslog doc14632345
Ref: 4ace14632345
Ref: library/syslog module-syslog14632345
Ref: dc14632345
Ref: library/syslog syslog-unix-syslog-library-routines14632345
Ref: 4acf14632345
Ref: library/syslog translation-repo14632345
Ref: 4ad014632345
Ref: library/syslog syslog syslog14632984
Ref: 54314632984
Ref: library/syslog syslog openlog14634424
Ref: 54114634424
Ref: library/syslog syslog closelog14635756
Ref: 54214635756
Ref: library/syslog syslog setlogmask14636607
Ref: 442d14636607
Ref: library/syslog syslog LOG_EMERG14637212
Ref: 4ad314637212
Ref: library/syslog syslog LOG_ALERT14637239
Ref: 4ad414637239
Ref: library/syslog syslog LOG_CRIT14637266
Ref: 4ad514637266
Ref: library/syslog syslog LOG_ERR14637292
Ref: 4ad614637292
Ref: library/syslog syslog LOG_WARNING14637317
Ref: 4ad714637317
Ref: library/syslog syslog LOG_NOTICE14637346
Ref: 4ad814637346
Ref: library/syslog syslog LOG_INFO14637374
Ref: 4ad114637374
Ref: library/syslog syslog LOG_DEBUG14637400
Ref: 4ad914637400
Ref: library/syslog syslog LOG_AUTH14637465
Ref: 4ada14637465
Ref: library/syslog syslog LOG_AUTHPRIV14637491
Ref: 4adb14637491
Ref: library/syslog syslog LOG_CRON14637521
Ref: 4adc14637521
Ref: library/syslog syslog LOG_DAEMON14637547
Ref: 4add14637547
Ref: library/syslog syslog LOG_FTP14637575
Ref: 4ade14637575
Ref: library/syslog syslog LOG_INSTALL14637600
Ref: 4adf14637600
Ref: library/syslog syslog LOG_KERN14637629
Ref: 4ae014637629
Ref: library/syslog syslog LOG_LAUNCHD14637655
Ref: 4ae114637655
Ref: library/syslog syslog LOG_LPR14637684
Ref: 4ae214637684
Ref: library/syslog syslog LOG_MAIL14637709
Ref: 4ae314637709
Ref: library/syslog syslog LOG_NETINFO14637735
Ref: 4ae414637735
Ref: library/syslog syslog LOG_NEWS14637764
Ref: 4ae514637764
Ref: library/syslog syslog LOG_RAS14637790
Ref: 4ae614637790
Ref: library/syslog syslog LOG_REMOTEAUTH14637815
Ref: 4ae714637815
Ref: library/syslog syslog LOG_SYSLOG14637847
Ref: 4ae814637847
Ref: library/syslog syslog LOG_USER14637875
Ref: 4ad214637875
Ref: library/syslog syslog LOG_UUCP14637901
Ref: 4ae914637901
Ref: library/syslog syslog LOG_LOCAL014637927
Ref: 4aea14637927
Ref: library/syslog syslog LOG_LOCAL114637955
Ref: 4aeb14637955
Ref: library/syslog syslog LOG_LOCAL214637983
Ref: 4aec14637983
Ref: library/syslog syslog LOG_LOCAL314638011
Ref: 4aed14638011
Ref: library/syslog syslog LOG_LOCAL414638039
Ref: 4aee14638039
Ref: library/syslog syslog LOG_LOCAL514638067
Ref: 4aef14638067
Ref: library/syslog syslog LOG_LOCAL614638095
Ref: 4af014638095
Ref: library/syslog syslog LOG_LOCAL714638123
Ref: 4af114638123
Ref: library/syslog syslog LOG_PID14638581
Ref: 4af214638581
Ref: library/syslog syslog LOG_CONS14638606
Ref: 4af314638606
Ref: library/syslog syslog LOG_NDELAY14638632
Ref: 4af414638632
Ref: library/syslog syslog LOG_ODELAY14638660
Ref: 4af514638660
Ref: library/syslog syslog LOG_NOWAIT14638688
Ref: 4af614638688
Ref: library/syslog syslog LOG_PERROR14638716
Ref: 4af714638716
Node: Examples<36>14638936
Ref: library/syslog examples14639024
Ref: 4af814639024
Node: Simple example14639092
Ref: library/syslog simple-example14639155
Ref: 4af914639155
Node: Modules command-line interface CLI14639667
Ref: library/cmdline doc14639823
Ref: 4afa14639823
Ref: library/cmdline modules-command-line-interface-cli14639823
Ref: 4afb14639823
Ref: library/cmdline translation-repo14639823
Ref: 4afc14639823
Node: Superseded Modules14641371
Ref: library/superseded doc14641520
Ref: 4afd14641520
Ref: library/superseded superseded14641520
Ref: 4afe14641520
Ref: library/superseded superseded-modules14641520
Ref: 4aff14641520
Ref: library/superseded translation-repo14641520
Ref: 4b0014641520
Ref: Superseded Modules-Footnote-114642619
Node: getopt — C-style parser for command line options14642661
Ref: library/getopt doc14642766
Ref: 4b0114642766
Ref: library/getopt getopt-c-style-parser-for-command-line-options14642766
Ref: 4b0214642766
Ref: library/getopt module-getopt14642766
Ref: 6114642766
Ref: library/getopt getopt getopt14644190
Ref: 150a14644190
Ref: library/getopt getopt gnu_getopt14646377
Ref: 150914646377
Ref: library/getopt getopt GetoptError14646952
Ref: 4b0314646952
Ref: library/getopt getopt error14647532
Ref: 4b0414647532
Ref: getopt — C-style parser for command line options-Footnote-114650741
Node: Removed Modules14650807
Ref: library/removed doc14650948
Ref: 4b0514650948
Ref: library/removed removed14650948
Ref: 4b0614650948
Ref: library/removed removed-modules14650948
Ref: 4b0714650948
Ref: library/removed translation-repo14650948
Ref: 4b0814650948
Node: aifc — Read and write AIFF and AIFC files14652271
Ref: library/aifc doc14652432
Ref: 4b0914652432
Ref: library/aifc aifc-read-and-write-aiff-and-aifc-files14652432
Ref: 4b0a14652432
Ref: library/aifc module-aifc14652432
Ref: 514652432
Ref: aifc — Read and write AIFF and AIFC files-Footnote-114652903
Ref: aifc — Read and write AIFF and AIFC files-Footnote-214652945
Node: asynchat — Asynchronous socket command/response handler14653000
Ref: library/asynchat doc14653210
Ref: 4b0b14653210
Ref: library/asynchat asynchat-asynchronous-socket-command-response-handler14653210
Ref: 4b0c14653210
Ref: library/asynchat module-asynchat14653210
Ref: 914653210
Ref: library/asynchat translation-repo14653210
Ref: 4b0d14653210
Ref: asynchat — Asynchronous socket command/response handler-Footnote-114653773
Ref: asynchat — Asynchronous socket command/response handler-Footnote-214653815
Node: asyncore — Asynchronous socket handler14653874
Ref: library/asyncore doc14654078
Ref: 4b0e14654078
Ref: library/asyncore asyncore-asynchronous-socket-handler14654078
Ref: 4b0f14654078
Ref: library/asyncore module-asyncore14654078
Ref: b14654078
Ref: library/asyncore translation-repo14654078
Ref: 4b1014654078
Ref: asyncore — Asynchronous socket handler-Footnote-114654607
Ref: asyncore — Asynchronous socket handler-Footnote-214654649
Node: audioop — Manipulate raw audio data14654708
Ref: library/audioop doc14654895
Ref: 4b1114654895
Ref: library/audioop audioop-manipulate-raw-audio-data14654895
Ref: 4b1214654895
Ref: library/audioop module-audioop14654895
Ref: d14654895
Ref: library/audioop translation-repo14654895
Ref: 4b1314654895
Ref: audioop — Manipulate raw audio data-Footnote-114655357
Ref: audioop — Manipulate raw audio data-Footnote-214655399
Node: cgi — Common Gateway Interface support14655457
Ref: library/cgi doc14655647
Ref: 4b1414655647
Ref: library/cgi cgi-common-gateway-interface-support14655647
Ref: 4b1514655647
Ref: library/cgi module-cgi14655647
Ref: 1514655647
Ref: library/cgi translation-repo14655647
Ref: 4b1614655647
Ref: cgi — Common Gateway Interface support-Footnote-114656271
Ref: cgi — Common Gateway Interface support-Footnote-214656313
Ref: cgi — Common Gateway Interface support-Footnote-314656358
Node: cgitb — Traceback manager for CGI scripts14656412
Ref: library/cgitb doc14656596
Ref: 4b1714656596
Ref: library/cgitb cgitb-traceback-manager-for-cgi-scripts14656596
Ref: 4b1814656596
Ref: library/cgitb module-cgitb14656596
Ref: 1614656596
Ref: library/cgitb translation-repo14656596
Ref: 4b1914656596
Ref: cgitb — Traceback manager for CGI scripts-Footnote-114657231
Ref: cgitb — Traceback manager for CGI scripts-Footnote-214657273
Ref: cgitb — Traceback manager for CGI scripts-Footnote-314657318
Node: chunk — Read IFF chunked data14657374
Ref: library/chunk doc14657560
Ref: 4b1a14657560
Ref: library/chunk chunk-read-iff-chunked-data14657560
Ref: 4b1b14657560
Ref: library/chunk module-chunk14657560
Ref: 1714657560
Ref: library/chunk translation-repo14657560
Ref: 4b1c14657560
Ref: chunk — Read IFF chunked data-Footnote-114658008
Ref: chunk — Read IFF chunked data-Footnote-214658050
Node: crypt — Function to check Unix passwords14658106
Ref: library/crypt doc14658301
Ref: 4b1d14658301
Ref: library/crypt crypt-function-to-check-unix-passwords14658301
Ref: 4b1e14658301
Ref: library/crypt module-crypt14658301
Ref: 2814658301
Ref: library/crypt translation-repo14658301
Ref: 4b1f14658301
Ref: crypt — Function to check Unix passwords-Footnote-114659026
Ref: crypt — Function to check Unix passwords-Footnote-214659068
Ref: crypt — Function to check Unix passwords-Footnote-314659114
Ref: crypt — Function to check Unix passwords-Footnote-414659155
Ref: crypt — Function to check Unix passwords-Footnote-514659201
Node: distutils — Building and installing Python modules14659257
Ref: library/distutils doc14659462
Ref: 4b2014659462
Ref: library/distutils distutils-building-and-installing-python-modules14659462
Ref: 4b2114659462
Ref: library/distutils module-distutils14659462
Ref: 3914659462
Ref: library/distutils translation-repo14659462
Ref: 4b2214659462
Ref: distutils — Building and installing Python modules-Footnote-114659987
Ref: distutils — Building and installing Python modules-Footnote-214660029
Ref: distutils — Building and installing Python modules-Footnote-314660088
Node: imghdr — Determine the type of an image14660148
Ref: library/imghdr doc14660346
Ref: 4b2314660346
Ref: library/imghdr imghdr-determine-the-type-of-an-image14660346
Ref: 4b2414660346
Ref: library/imghdr module-imghdr14660346
Ref: 7514660346
Ref: library/imghdr translation-repo14660346
Ref: 4b2514660346
Ref: imghdr — Determine the type of an image-Footnote-114660988
Ref: imghdr — Determine the type of an image-Footnote-214661030
Ref: imghdr — Determine the type of an image-Footnote-314661073
Ref: imghdr — Determine the type of an image-Footnote-414661117
Ref: imghdr — Determine the type of an image-Footnote-514661164
Node: imp — Access the import internals14661221
Ref: library/imp doc14661400
Ref: 4b2614661400
Ref: library/imp imp-access-the-import-internals14661400
Ref: 4b2714661400
Ref: library/imp module-imp14661400
Ref: 7614661400
Ref: library/imp translation-repo14661400
Ref: 4b2814661400
Ref: imp — Access the import internals-Footnote-114661922
Node: mailcap — Mailcap file handling14661976
Ref: library/mailcap doc14662165
Ref: 4b2914662165
Ref: library/mailcap mailcap-mailcap-file-handling14662165
Ref: 4b2a14662165
Ref: library/mailcap module-mailcap14662165
Ref: 8c14662165
Ref: library/mailcap translation-repo14662165
Ref: 4b2b14662165
Ref: mailcap — Mailcap file handling-Footnote-114662621
Ref: mailcap — Mailcap file handling-Footnote-214662663
Node: msilib — Read and write Microsoft Installer files14662721
Ref: library/msilib doc14662920
Ref: 4b2c14662920
Ref: library/msilib module-msilib14662920
Ref: 9214662920
Ref: library/msilib msilib-read-and-write-microsoft-installer-files14662920
Ref: 4b2d14662920
Ref: library/msilib translation-repo14662920
Ref: 4b2e14662920
Ref: msilib — Read and write Microsoft Installer files-Footnote-114663411
Ref: msilib — Read and write Microsoft Installer files-Footnote-214663453
Node: nis — Interface to Sun’s NIS Yellow Pages14663510
Ref: library/nis doc14663708
Ref: 4b2f14663708
Ref: library/nis module-nis14663708
Ref: 9c14663708
Ref: library/nis nis-interface-to-suns-nis-yellow-pages14663708
Ref: 4b3014663708
Ref: library/nis translation-repo14663708
Ref: 4b3114663708
Ref: nis — Interface to Sun’s NIS Yellow Pages-Footnote-114664186
Ref: nis — Interface to Sun’s NIS Yellow Pages-Footnote-214664228
Node: nntplib — NNTP protocol client14664282
Ref: library/nntplib doc14664483
Ref: 4b3214664483
Ref: library/nntplib module-nntplib14664483
Ref: 9d14664483
Ref: library/nntplib nntplib-nntp-protocol-client14664483
Ref: 4b3314664483
Ref: library/nntplib translation-repo14664483
Ref: 4b3414664483
Ref: nntplib — NNTP protocol client-Footnote-114664937
Ref: nntplib — NNTP protocol client-Footnote-214664979
Node: ossaudiodev — Access to OSS-compatible audio devices14665037
Ref: library/ossaudiodev doc14665231
Ref: 4b3514665231
Ref: library/ossaudiodev module-ossaudiodev14665231
Ref: a314665231
Ref: library/ossaudiodev ossaudiodev-access-to-oss-compatible-audio-devices14665231
Ref: 4b3614665231
Ref: library/ossaudiodev translation-repo14665231
Ref: 4b3714665231
Ref: ossaudiodev — Access to OSS-compatible audio devices-Footnote-114665733
Ref: ossaudiodev — Access to OSS-compatible audio devices-Footnote-214665775
Node: pipes — Interface to shell pipelines14665837
Ref: library/pipes doc14666020
Ref: 4b3814666020
Ref: library/pipes module-pipes14666020
Ref: a814666020
Ref: library/pipes pipes-interface-to-shell-pipelines14666020
Ref: 4b3914666020
Ref: library/pipes translation-repo14666020
Ref: 4b3a14666020
Ref: pipes — Interface to shell pipelines-Footnote-114666551
Ref: pipes — Interface to shell pipelines-Footnote-214666593
Node: smtpd — SMTP Server14666649
Ref: library/smtpd doc14666817
Ref: 4b3b14666817
Ref: library/smtpd module-smtpd14666817
Ref: c914666817
Ref: library/smtpd smtpd-smtp-server14666817
Ref: 4b3c14666817
Ref: library/smtpd translation-repo14666817
Ref: 4b3d14666817
Ref: smtpd — SMTP Server-Footnote-114667378
Ref: smtpd — SMTP Server-Footnote-214667420
Ref: smtpd — SMTP Server-Footnote-314667463
Node: sndhdr — Determine type of sound file14667519
Ref: library/sndhdr doc14667686
Ref: 4b3e14667686
Ref: library/sndhdr module-sndhdr14667686
Ref: cb14667686
Ref: library/sndhdr sndhdr-determine-type-of-sound-file14667686
Ref: 4b3f14667686
Ref: library/sndhdr translation-repo14667686
Ref: 4b4014667686
Ref: sndhdr — Determine type of sound file-Footnote-114668322
Ref: sndhdr — Determine type of sound file-Footnote-214668364
Ref: sndhdr — Determine type of sound file-Footnote-314668407
Ref: sndhdr — Determine type of sound file-Footnote-414668451
Ref: sndhdr — Determine type of sound file-Footnote-514668498
Node: spwd — The shadow password database14668555
Ref: library/spwd doc14668738
Ref: 4b4114668738
Ref: library/spwd module-spwd14668738
Ref: ce14668738
Ref: library/spwd spwd-the-shadow-password-database14668738
Ref: 4b4214668738
Ref: library/spwd translation-repo14668738
Ref: 4b4314668738
Ref: spwd — The shadow password database-Footnote-114669335
Ref: spwd — The shadow password database-Footnote-214669377
Ref: spwd — The shadow password database-Footnote-314669422
Node: sunau — Read and write Sun AU files14669477
Ref: library/sunau doc14669648
Ref: 4b4414669648
Ref: library/sunau module-sunau14669648
Ref: d714669648
Ref: library/sunau sunau-read-and-write-sun-au-files14669648
Ref: 4b4514669648
Ref: library/sunau translation-repo14669648
Ref: 4b4614669648
Ref: sunau — Read and write Sun AU files-Footnote-114670110
Ref: sunau — Read and write Sun AU files-Footnote-214670152
Node: telnetlib — Telnet client14670208
Ref: library/telnetlib doc14670381
Ref: 4b4714670381
Ref: library/telnetlib module-telnetlib14670381
Ref: df14670381
Ref: library/telnetlib telnetlib-telnet-client14670381
Ref: 4b4814670381
Ref: library/telnetlib translation-repo14670381
Ref: 4b4914670381
Ref: telnetlib — Telnet client-Footnote-114670981
Ref: telnetlib — Telnet client-Footnote-214671023
Ref: telnetlib — Telnet client-Footnote-314671068
Ref: telnetlib — Telnet client-Footnote-414671111
Node: uu — Encode and decode uuencode files14671171
Ref: library/uu doc14671344
Ref: 4b4a14671344
Ref: library/uu module-uu14671344
Ref: 10f14671344
Ref: library/uu translation-repo14671344
Ref: 4b4b14671344
Ref: library/uu uu-encode-and-decode-uuencode-files14671344
Ref: 4b4c14671344
Ref: uu — Encode and decode uuencode files-Footnote-114671807
Ref: uu — Encode and decode uuencode files-Footnote-214671849
Node: xdrlib — Encode and decode XDR data14671902
Ref: library/xdrlib doc14672039
Ref: 4b4d14672039
Ref: library/xdrlib module-xdrlib14672039
Ref: 11f14672039
Ref: library/xdrlib translation-repo14672039
Ref: 4b4e14672039
Ref: library/xdrlib xdrlib-encode-and-decode-xdr-data14672039
Ref: 4b4f14672039
Ref: library/security_warnings security-warnings14672466
Ref: 4b5014672466
Ref: xdrlib — Encode and decode XDR data-Footnote-114672502
Ref: xdrlib — Encode and decode XDR data-Footnote-214672544
Node: Security Considerations<3>14672601
Ref: library/security_warnings doc14672715
Ref: 4b5114672715
Ref: library/security_warnings security-considerations14672715
Ref: 4b5214672715
Ref: library/security_warnings translation-repo14672715
Ref: 4b5314672715
Ref: Security Considerations<3>-Footnote-114674494
Node: Extending and Embedding the Python Interpreter14674553
Ref: extending/index doc14674713
Ref: 4b5414674713
Ref: extending/index extending-and-embedding-the-python-interpreter14674713
Ref: 4b5514674713
Ref: extending/index extending-index14674713
Ref: 1d6e14674713
Ref: extending/index translation-repo14674713
Ref: 4b5614674713
Node: Recommended third party tools14676015
Ref: extending/index recommended-third-party-tools14676181
Ref: 4b5714676181
Node: Creating extensions without third party tools14676494
Ref: extending/index creating-extensions-without-third-party-tools14676722
Ref: 4b5914676722
Ref: Creating extensions without third party tools-Footnote-114677453
Node: Extending Python with C or C++14677495
Ref: extending/extending doc14677649
Ref: 4b5a14677649
Ref: extending/extending extending-intro14677649
Ref: 4b5b14677649
Ref: extending/extending extending-python-with-c-or-c14677649
Ref: 4b5c14677649
Ref: Extending Python with C or C++-Footnote-114679580
Node: A Simple Example14679617
Ref: extending/extending a-simple-example14679741
Ref: 4b5d14679741
Ref: extending/extending extending-simpleexample14679741
Ref: 4b5e14679741
Ref: A Simple Example-Footnote-114684220
Node: Intermezzo Errors and Exceptions14684370
Ref: extending/extending extending-errors14684522
Ref: 4b5f14684522
Ref: extending/extending intermezzo-errors-and-exceptions14684522
Ref: 4b6014684522
Node: Back to the Example14692598
Ref: extending/extending back-to-the-example14692789
Ref: 4b6714692789
Ref: extending/extending backtoexample14692789
Ref: 4b6814692789
Node: The Module’s Method Table and Initialization Function14694446
Ref: extending/extending methodtable14694628
Ref: 4b6a14694628
Ref: extending/extending the-module-s-method-table-and-initialization-function14694628
Ref: 4b6b14694628
Node: Compilation and Linkage14699636
Ref: extending/extending compilation14699830
Ref: 4b7014699830
Ref: extending/extending compilation-and-linkage14699830
Ref: 4b7114699830
Node: Calling Python Functions from C14701304
Ref: extending/extending calling-python-functions-from-c14701487
Ref: 4b7314701487
Ref: extending/extending callingpython14701487
Ref: 4b7414701487
Node: Extracting Parameters in Extension Functions14708157
Ref: extending/extending extracting-parameters-in-extension-functions14708359
Ref: 4b7814708359
Ref: extending/extending parsetuple14708359
Ref: 4b7514708359
Node: Keyword Parameters for Extension Functions14710992
Ref: extending/extending keyword-parameters-for-extension-functions14711188
Ref: 4b7914711188
Ref: extending/extending parsetupleandkeywords14711188
Ref: 4b7a14711188
Node: Building Arbitrary Values14713891
Ref: extending/extending building-arbitrary-values14714059
Ref: 4b7b14714059
Ref: extending/extending buildvalue14714059
Ref: 4b7c14714059
Node: Reference Counts14716145
Ref: extending/extending refcounts14716296
Ref: 4b7614716296
Ref: extending/extending reference-counts14716296
Ref: 4b7d14716296
Node: Reference Counting in Python14720741
Ref: extending/extending refcountsinpython14720846
Ref: 4b7e14720846
Ref: extending/extending reference-counting-in-python14720846
Ref: 4b7f14720846
Ref: Reference Counting in Python-Footnote-114723219
Ref: Reference Counting in Python-Footnote-214723343
Node: Ownership Rules14723514
Ref: extending/extending ownership-rules14723636
Ref: 4b8014723636
Ref: extending/extending ownershiprules14723636
Ref: 4b8114723636
Node: Thin Ice14726093
Ref: extending/extending thin-ice14726200
Ref: 4b8514726200
Ref: extending/extending thinice14726200
Ref: 4b8614726200
Ref: Thin Ice-Footnote-114729905
Node: NULL Pointers14729947
Ref: extending/extending null-pointers14730030
Ref: 4b8914730030
Ref: extending/extending nullpointers14730030
Ref: 4b8a14730030
Ref: NULL Pointers-Footnote-114731655
Node: Writing Extensions in C++14731792
Ref: extending/extending cplusplus14731959
Ref: 4b8b14731959
Ref: extending/extending writing-extensions-in-c14731959
Ref: 4b8c14731959
Node: Providing a C API for an Extension Module14732679
Ref: extending/extending providing-a-c-api-for-an-extension-module14732821
Ref: 4b8d14732821
Ref: extending/extending using-capsules14732821
Ref: 13aa14732821
Node: Defining Extension Types Tutorial14741384
Ref: extending/newtypes_tutorial doc14741587
Ref: 196014741587
Ref: extending/newtypes_tutorial defining-extension-types-tutorial14741587
Ref: 4b8f14741587
Ref: extending/newtypes_tutorial defining-new-types14741587
Ref: 4b9014741587
Ref: extending/newtypes_tutorial translation-repo14741587
Ref: 4b9114741587
Node: The Basics14742231
Ref: extending/newtypes_tutorial dnt-basics14742364
Ref: 4b9214742364
Ref: extending/newtypes_tutorial the-basics14742364
Ref: 4b9314742364
Node: Adding data and methods to the Basic example14751771
Ref: extending/newtypes_tutorial adding-data-and-methods-to-the-basic-example14751957
Ref: 4b9914751957
Ref: Adding data and methods to the Basic example-Footnote-114768143
Ref: Adding data and methods to the Basic example-Footnote-214768236
Node: Providing finer control over data attributes14768373
Ref: extending/newtypes_tutorial providing-finer-control-over-data-attributes14768585
Ref: 4ba014768585
Ref: Providing finer control over data attributes-Footnote-114778362
Node: Supporting cyclic garbage collection14778742
Ref: extending/newtypes_tutorial supporting-cyclic-garbage-collection14778933
Ref: 4ba214778933
Ref: Supporting cyclic garbage collection-Footnote-114789512
Node: Subclassing other types14789686
Ref: extending/newtypes_tutorial subclassing-other-types14789824
Ref: 4ba414789824
Node: Defining Extension Types Assorted Topics14795054
Ref: extending/newtypes doc14795256
Ref: 4ba614795256
Ref: extending/newtypes defining-extension-types-assorted-topics14795256
Ref: 4ba714795256
Ref: extending/newtypes new-types-topics14795256
Ref: 4ba814795256
Ref: extending/newtypes translation-repo14795256
Ref: 4ba914795256
Ref: extending/newtypes dnt-type-methods14795353
Ref: 4baa14795353
Node: Finalization and De-allocation14800113
Ref: extending/newtypes finalization-and-de-allocation14800248
Ref: 4bab14800248
Ref: Finalization and De-allocation-Footnote-114803733
Node: Object Presentation14803775
Ref: extending/newtypes object-presentation14803939
Ref: 4bad14803939
Node: Attribute Management14805559
Ref: extending/newtypes attribute-management14805710
Ref: 4bb014805710
Node: Generic Attribute Management14807259
Ref: extending/newtypes generic-attribute-management14807387
Ref: 4b9d14807387
Ref: extending/newtypes id114807387
Ref: 4bb114807387
Node: Type-specific Attribute Management14810959
Ref: extending/newtypes type-specific-attribute-management14811087
Ref: 4bb614811087
Node: Object Comparison14812848
Ref: extending/newtypes object-comparison14813005
Ref: 4bb914813005
Node: Abstract Protocol Support14814788
Ref: extending/newtypes abstract-protocol-support14814947
Ref: 4bbc14814947
Node: Weak Reference Support14820617
Ref: extending/newtypes weak-reference-support14820775
Ref: 4bc114820775
Ref: extending/newtypes weakref-support14820775
Ref: 271c14820775
Node: More Suggestions14822070
Ref: extending/newtypes more-suggestions14822194
Ref: 4bc214822194
Node: Building C and C++ Extensions14823163
Ref: extending/building doc14823372
Ref: 4bc314823372
Ref: extending/building building14823372
Ref: 4b7214823372
Ref: extending/building building-c-and-c-extensions14823372
Ref: 4bc414823372
Ref: extending/building translation-repo14823372
Ref: 4bc514823372
Ref: extending/building c PyInit_modulename14823870
Ref: 4bc614823870
Ref: extending/building install-index14825081
Ref: f2d14825081
Ref: Building C and C++ Extensions-Footnote-114825178
Node: Building C and C++ Extensions with setuptools14825220
Ref: extending/building building-c-and-c-extensions-with-setuptools14825331
Ref: 4bc914825331
Ref: extending/building setuptools-index14825331
Ref: f2e14825331
Node: Building C and C++ Extensions on Windows14825694
Ref: extending/windows doc14825854
Ref: 4bca14825854
Ref: extending/windows building-c-and-c-extensions-on-windows14825854
Ref: 4bcb14825854
Ref: extending/windows building-on-windows14825854
Ref: 1fde14825854
Ref: extending/windows translation-repo14825854
Ref: 4bcc14825854
Node: A Cookbook Approach14827123
Ref: extending/windows a-cookbook-approach14827264
Ref: 4bcd14827264
Ref: extending/windows win-cookbook14827264
Ref: 4bce14827264
Ref: A Cookbook Approach-Footnote-114827893
Node: Differences Between Unix and Windows14827971
Ref: extending/windows differences-between-unix-and-windows14828143
Ref: 4bcf14828143
Ref: extending/windows dynamic-linking14828143
Ref: 4bd014828143
Node: Using DLLs in Practice14831066
Ref: extending/windows using-dlls-in-practice14831210
Ref: 4bd114831210
Ref: extending/windows win-dlls14831210
Ref: 4bd214831210
Node: Embedding the CPython runtime in a larger application14832741
Ref: extending/index embedding-the-cpython-runtime-in-a-larger-application14832931
Ref: 4bd314832931
Node: Embedding Python in Another Application14833373
Ref: extending/embedding doc14833502
Ref: 4bd414833502
Ref: extending/embedding embedding14833502
Ref: 1ffc14833502
Ref: extending/embedding embedding-python-in-another-application14833502
Ref: 4bd514833502
Node: Very High Level Embedding14835846
Ref: extending/embedding high-level-embedding14836000
Ref: 4bd814836000
Ref: extending/embedding very-high-level-embedding14836000
Ref: 4bd914836000
Node: Beyond Very High Level Embedding An overview14838332
Ref: extending/embedding beyond-very-high-level-embedding-an-overview14838509
Ref: 4bda14838509
Ref: extending/embedding lower-level-embedding14838509
Ref: 4bdb14838509
Node: Pure Embedding14840228
Ref: extending/embedding id114840405
Ref: 4bdc14840405
Ref: extending/embedding pure-embedding14840405
Ref: 4bdd14840405
Node: Extending Embedded Python14845030
Ref: extending/embedding extending-embedded-python14845186
Ref: 4bdf14845186
Ref: extending/embedding extending-with-embedding14845186
Ref: 4be014845186
Node: Embedding Python in C++14847223
Ref: extending/embedding embedding-python-in-c14847410
Ref: 4be114847410
Ref: extending/embedding embeddingincplusplus14847410
Ref: 4be214847410
Node: Compiling and Linking under Unix-like systems14847782
Ref: extending/embedding compiling14847935
Ref: 4bde14847935
Ref: extending/embedding compiling-and-linking-under-unix-like-systems14847935
Ref: 4be314847935
Node: Python/C API Reference Manual14850132
Ref: c-api/index doc14850290
Ref: 4be514850290
Ref: c-api/index c-api-index14850290
Ref: 1d6f14850290
Ref: c-api/index python-c-api-reference-manual14850290
Ref: 4be614850290
Ref: c-api/index translation-repo14850290
Ref: 4be714850290
Node: Introduction<13>14851145
Ref: c-api/intro doc14851251
Ref: 4be814851251
Ref: c-api/intro api-intro14851251
Ref: 4be914851251
Ref: c-api/intro introduction14851251
Ref: 4bea14851251
Node: Coding standards14852892
Ref: c-api/intro coding-standards14852983
Ref: 4beb14852983
Ref: Coding standards-Footnote-114853422
Node: Include Files14853464
Ref: c-api/intro api-includes14853577
Ref: 78714853577
Ref: c-api/intro include-files14853577
Ref: 4bec14853577
Node: Useful macros14856125
Ref: c-api/intro useful-macros14856256
Ref: 4bed14856256
Ref: c-api/intro c PyMODINIT_FUNC14856544
Ref: 152214856544
Ref: c-api/intro c Py_ABS14857340
Ref: 4bee14857340
Ref: c-api/intro c Py_ALIGNED14857575
Ref: 4bef14857575
Ref: c-api/intro c Py_ARITHMETIC_RIGHT_SHIFT14857760
Ref: 4bf014857760
Ref: c-api/intro c Py_ALWAYS_INLINE14858710
Ref: 1a1114858710
Ref: c-api/intro c Py_CAN_START_THREADS14859688
Ref: 4bf114859688
Ref: c-api/intro c Py_CHARMASK14859992
Ref: 4bf214859992
Ref: c-api/intro c Py_DEPRECATED14860174
Ref: ab914860174
Ref: c-api/intro c Py_FORCE_EXPANSION14860448
Ref: 4bf314860448
Ref: c-api/intro c Py_GCC_ATTRIBUTE14860650
Ref: 4bf414860650
Ref: c-api/intro c Py_GETENV14860951
Ref: 4bf514860951
Ref: c-api/intro c Py_LL14861128
Ref: 4bf614861128
Ref: c-api/intro c Py_LOCAL14861520
Ref: 149914861520
Ref: c-api/intro c Py_LOCAL_INLINE14861753
Ref: 149a14861753
Ref: c-api/intro c Py_LOCAL_SYMBOL14861888
Ref: 4bf714861888
Ref: c-api/intro c Py_MAX14862177
Ref: 4bf814862177
Ref: c-api/intro c Py_MEMBER_SIZE14862293
Ref: 4bf914862293
Ref: c-api/intro c Py_MIN14862438
Ref: 4bfa14862438
Ref: c-api/intro c Py_NO_INLINE14862554
Ref: 1a1214862554
Ref: c-api/intro c Py_SAFE_DOWNCAST14862854
Ref: 4bfb14862854
Ref: c-api/intro c Py_STRINGIFY14863528
Ref: 4bfc14863528
Ref: c-api/intro c Py_ULL14863681
Ref: 4bfd14863681
Ref: c-api/intro c Py_UNREACHABLE14864051
Ref: bd314864051
Ref: c-api/intro c Py_UNUSED14865209
Ref: 182914865209
Ref: c-api/intro c Py_BUILD_ASSERT14865433
Ref: 174614865433
Ref: c-api/intro c Py_BUILD_ASSERT_EXPR14865742
Ref: 174714865742
Ref: c-api/intro c PyDoc_STRVAR14866145
Ref: 1b0414866145
Ref: c-api/intro c PyDoc_STR14866722
Ref: 193c14866722
Ref: c-api/intro c PyDoc_VAR14867235
Ref: 1b9e14867235
Ref: c-api/intro c Py_ARRAY_LENGTH14867583
Ref: 4bfe14867583
Ref: c-api/intro c Py_EXPORTED_SYMBOL14868046
Ref: 4bff14868046
Ref: c-api/intro c Py_IMPORTED_SYMBOL14868407
Ref: 4c0014868407
Ref: c-api/intro c PyAPI_FUNC14868641
Ref: 4c0114868641
Ref: c-api/intro c PyAPI_DATA14868944
Ref: 4c0214868944
Ref: c-api/intro c Py_VA_COPY14869262
Ref: 4c0314869262
Ref: Useful macros-Footnote-114869583
Ref: Useful macros-Footnote-214869625
Ref: Useful macros-Footnote-314869690
Ref: Useful macros-Footnote-414869732
Node: Objects Types and Reference Counts14869774
Ref: c-api/intro api-objects14869906
Ref: 4c0414869906
Ref: c-api/intro objects-types-and-reference-counts14869906
Ref: 4c0514869906
Node: Reference Counts<2>14871276
Ref: c-api/intro api-refcounts14871380
Ref: 4c0614871380
Ref: c-api/intro reference-counts14871380
Ref: 4c0714871380
Node: Reference Count Details14875292
Ref: c-api/intro api-refcountdetails14875371
Ref: 4c0814875371
Ref: c-api/intro reference-count-details14875371
Ref: 4c0914875371
Node: Types14882572
Ref: c-api/intro api-types14882676
Ref: 4c0c14882676
Ref: c-api/intro types14882676
Ref: 4c0d14882676
Ref: c-api/intro c Py_ssize_t14883130
Ref: a6e14883130
Ref: Types-Footnote-114883531
Node: Exceptions<21>14883573
Ref: c-api/intro api-exceptions14883711
Ref: 4c0e14883711
Ref: c-api/intro exceptions14883711
Ref: 4c0f14883711
Node: Embedding Python<2>14889850
Ref: c-api/intro api-embedding14889970
Ref: 4c1114889970
Ref: c-api/intro embedding-python14889970
Ref: 4c1214889970
Node: Debugging Builds14893180
Ref: c-api/intro api-debugging14893318
Ref: 4c1414893318
Ref: c-api/intro debugging-builds14893318
Ref: 4c1514893318
Ref: c-api/intro c Py_DEBUG14893947
Ref: 437b14893947
Node: Recommended third party tools<2>14895045
Ref: c-api/intro c-api-tools14895155
Ref: 4b5814895155
Ref: c-api/intro recommended-third-party-tools14895155
Ref: 4c1614895155
Ref: Recommended third party tools<2>-Footnote-114896562
Ref: Recommended third party tools<2>-Footnote-214896590
Ref: Recommended third party tools<2>-Footnote-314896626
Ref: Recommended third party tools<2>-Footnote-414896658
Ref: Recommended third party tools<2>-Footnote-514896701
Ref: Recommended third party tools<2>-Footnote-614896735
Ref: Recommended third party tools<2>-Footnote-714896776
Ref: Recommended third party tools<2>-Footnote-814896801
Ref: Recommended third party tools<2>-Footnote-914896830
Node: C API Stability14896903
Ref: c-api/stable doc14897043
Ref: 4c1714897043
Ref: c-api/stable c-api-stability14897043
Ref: 4c1814897043
Ref: c-api/stable stable14897043
Ref: 55614897043
Ref: c-api/stable translation-repo14897043
Ref: 4c1914897043
Ref: C API Stability-Footnote-114898574
Ref: C API Stability-Footnote-214898616
Node: Unstable C API14898671
Ref: c-api/stable id114898781
Ref: 4c1b14898781
Ref: c-api/stable unstable-c-api14898781
Ref: 54a14898781
Node: Stable Application Binary Interface14899279
Ref: c-api/stable stable-application-binary-interface14899421
Ref: 4c1c14899421
Node: Limited C API14899780
Ref: c-api/stable id214899884
Ref: 4c1d14899884
Ref: c-api/stable limited-c-api14899884
Ref: 39914899884
Ref: c-api/stable c Py_LIMITED_API14900167
Ref: 42114900167
Node: Stable ABI14901022
Ref: c-api/stable id314901168
Ref: 4c1e14901168
Ref: c-api/stable stable-abi14901168
Ref: 4c1f14901168
Ref: Stable ABI-Footnote-114902584
Node: Limited API Scope and Performance14902626
Ref: c-api/stable limited-api-scope-and-performance14902778
Ref: 4c2014902778
Node: Limited API Caveats14903900
Ref: c-api/stable limited-api-caveats14904033
Ref: 4c2214904033
Node: Platform Considerations14905686
Ref: c-api/stable platform-considerations14905837
Ref: 4c2314905837
Ref: c-api/stable stable-abi-platform14905837
Ref: 4c1a14905837
Node: Contents of Limited API14906455
Ref: c-api/stable contents-of-limited-api14906562
Ref: 4c2414906562
Ref: c-api/stable limited-api-list14906562
Ref: 79d14906562
Node: The Very High Level Layer14947950
Ref: c-api/veryhigh doc14948092
Ref: 4e7b14948092
Ref: c-api/veryhigh the-very-high-level-layer14948092
Ref: 4e7c14948092
Ref: c-api/veryhigh translation-repo14948092
Ref: 4e7d14948092
Ref: c-api/veryhigh veryhigh14948092
Ref: 4e7e14948092
Ref: c-api/veryhigh c PyRun_AnyFile14949151
Ref: 4e8314949151
Ref: c-api/veryhigh c PyRun_AnyFileFlags14949376
Ref: 4e8514949376
Ref: c-api/veryhigh c PyRun_AnyFileEx14949618
Ref: 4e8614949618
Ref: c-api/veryhigh c PyRun_AnyFileExFlags14949847
Ref: 4e8414949847
Ref: c-api/veryhigh c PyRun_SimpleString14950509
Ref: 4bd614950509
Ref: c-api/veryhigh c PyRun_SimpleStringFlags14950736
Ref: 4e8814950736
Ref: c-api/veryhigh c PyRun_SimpleFile14951420
Ref: 4bd714951420
Ref: c-api/veryhigh c PyRun_SimpleFileEx14951651
Ref: 4e8914951651
Ref: c-api/veryhigh c PyRun_SimpleFileExFlags14951873
Ref: 1a7014951873
Ref: c-api/veryhigh c PyRun_InteractiveOneObject14952552
Ref: 4e8a14952552
Ref: c-api/veryhigh c PyRun_InteractiveOne14953266
Ref: 4e8b14953266
Ref: c-api/veryhigh c PyRun_InteractiveOneFlags14953484
Ref: 4e8c14953484
Ref: c-api/veryhigh c PyRun_InteractiveLoop14953776
Ref: 4e8714953776
Ref: c-api/veryhigh c PyRun_InteractiveLoopFlags14953996
Ref: 4e8d14953996
Ref: c-api/veryhigh c PyOS_InputHook14954444
Ref: 58814954444
Ref: c-api/veryhigh c PyOS_ReadlineFunctionPointer14955063
Ref: 58914955063
Ref: c-api/veryhigh c PyRun_String14956193
Ref: 1b6b14956193
Ref: c-api/veryhigh c PyRun_StringFlags14956477
Ref: 4e8e14956477
Ref: c-api/veryhigh c PyRun_File14957175
Ref: 4e9014957175
Ref: c-api/veryhigh c PyRun_FileEx14957501
Ref: 4e9214957501
Ref: c-api/veryhigh c PyRun_FileFlags14957823
Ref: 4e9314957823
Ref: c-api/veryhigh c PyRun_FileExFlags14958158
Ref: 4e9114958158
Ref: c-api/veryhigh c Py_CompileString14958744
Ref: 88c14958744
Ref: c-api/veryhigh c Py_CompileStringFlags14959064
Ref: 4e9414959064
Ref: c-api/veryhigh c Py_CompileStringObject14959370
Ref: 4e9614959370
Ref: c-api/veryhigh c Py_CompileStringExFlags14960471
Ref: 4e9514960471
Ref: c-api/veryhigh c PyEval_EvalCode14960860
Ref: 88d14960860
Ref: c-api/veryhigh c PyEval_EvalCodeEx14961236
Ref: 187d14961236
Ref: c-api/veryhigh c PyEval_EvalFrame14961968
Ref: 4c9d14961968
Ref: c-api/veryhigh c PyEval_EvalFrameEx14962264
Ref: 106b14962264
Ref: c-api/veryhigh c PyEval_MergeCompilerFlags14963015
Ref: 4e9714963015
Ref: c-api/veryhigh c PyCompilerFlags14963207
Ref: ab614963207
Ref: c-api/veryhigh c PyCompilerFlags cf_flags14963747
Ref: 4e9814963747
Ref: c-api/veryhigh c PyCompilerFlags cf_feature_version14963807
Ref: 4e9914963807
Ref: c-api/veryhigh c PyCF_ALLOW_TOP_LEVEL_AWAIT14964236
Ref: 4e9a14964236
Ref: c-api/veryhigh c PyCF_ONLY_AST14964281
Ref: 4e9b14964281
Ref: c-api/veryhigh c PyCF_OPTIMIZED_AST14964313
Ref: 4e9c14964313
Ref: c-api/veryhigh c PyCF_TYPE_COMMENTS14964350
Ref: 4e9d14964350
Node: Available start symbols14964886
Ref: c-api/veryhigh available-start-symbols14964993
Ref: 4ea014964993
Ref: c-api/veryhigh start-symbols14964993
Ref: 4e8f14964993
Ref: c-api/veryhigh c Py_eval_input14965054
Ref: 4e7f14965054
Ref: c-api/veryhigh c Py_file_input14965211
Ref: 4e8014965211
Ref: c-api/veryhigh c Py_single_input14965496
Ref: 4e8114965496
Ref: c-api/veryhigh c Py_func_type_input14965721
Ref: 4e8214965721
Ref: Available start symbols-Footnote-114966176
Ref: Available start symbols-Footnote-214966218
Node: Stack Effects14966260
Ref: c-api/veryhigh stack-effects14966367
Ref: 4ea114966367
Ref: c-api/veryhigh c PY_INVALID_STACK_EFFECT14966459
Ref: 4ea214966459
Ref: c-api/veryhigh c PyCompile_OpcodeStackEffect14966637
Ref: 4ea314966637
Ref: c-api/veryhigh c PyCompile_OpcodeStackEffectWithJump14966929
Ref: 1be314966929
Node: Reference Counting14967459
Ref: c-api/refcounting doc14967604
Ref: 4ea414967604
Ref: c-api/refcounting countingrefs14967604
Ref: 4ea514967604
Ref: c-api/refcounting reference-counting14967604
Ref: 4ea614967604
Ref: c-api/refcounting translation-repo14967604
Ref: 4ea714967604
Ref: c-api/refcounting c Py_REFCNT14967751
Ref: 8b114967751
Ref: c-api/refcounting c Py_SET_REFCNT14968530
Ref: 8b214968530
Ref: c-api/refcounting c Py_INCREF14968963
Ref: 57114968963
Ref: c-api/refcounting c Py_XINCREF14969839
Ref: a7314969839
Ref: c-api/refcounting c Py_NewRef14970044
Ref: 8a114970044
Ref: c-api/refcounting c Py_XNewRef14970755
Ref: 8a214970755
Ref: c-api/refcounting c Py_DECREF14971061
Ref: 57214971061
Ref: c-api/refcounting c Py_XDECREF14972675
Ref: 79214972675
Ref: c-api/refcounting c Py_CLEAR14972908
Ref: 57b14972908
Ref: c-api/refcounting c Py_IncRef14973733
Ref: 4df214973733
Ref: c-api/refcounting c Py_DecRef14974009
Ref: 4dea14974009
Ref: c-api/refcounting c Py_SETREF14974273
Ref: 57c14974273
Ref: c-api/refcounting c Py_XSETREF14975029
Ref: 57d14975029
Ref: Reference Counting-Footnote-114975405
Ref: Reference Counting-Footnote-214975447
Node: Exception Handling14975489
Ref: c-api/exceptions doc14975621
Ref: 4ea814975621
Ref: c-api/exceptions exception-handling14975621
Ref: 4ea914975621
Ref: c-api/exceptions exceptionhandling14975621
Ref: 464d14975621
Ref: c-api/exceptions translation-repo14975621
Ref: 4eaa14975621
Node: Printing and clearing14977924
Ref: c-api/exceptions printing-and-clearing14978027
Ref: 4eab14978027
Ref: c-api/exceptions c PyErr_Clear14978084
Ref: 106e14978084
Ref: c-api/exceptions c PyErr_PrintEx14978252
Ref: 4c9014978252
Ref: c-api/exceptions c PyErr_Print14979186
Ref: 1ad314979186
Ref: c-api/exceptions c PyErr_WriteUnraisable14979306
Ref: 35014979306
Ref: c-api/exceptions c PyErr_FormatUnraisable14980285
Ref: 34f14980285
Ref: c-api/exceptions c PyErr_DisplayException14980799
Ref: 40514980799
Node: Raising exceptions14981074
Ref: c-api/exceptions raising-exceptions14981202
Ref: 4eac14981202
Ref: c-api/exceptions c PyErr_SetString14981442
Ref: 57f14981442
Ref: c-api/exceptions c PyErr_SetObject14981967
Ref: 57e14981967
Ref: c-api/exceptions c PyErr_Format14982237
Ref: ee514982237
Ref: c-api/exceptions c PyErr_FormatV14982740
Ref: ee414982740
Ref: c-api/exceptions c PyErr_SetNone14983104
Ref: 4c9914983104
Ref: c-api/exceptions c PyErr_BadArgument14983268
Ref: 4c8d14983268
Ref: c-api/exceptions c PyErr_NoMemory14983564
Ref: 4b6314983564
Ref: c-api/exceptions c PyErr_SetFromErrno14983895
Ref: 4b6214983895
Ref: c-api/exceptions c PyErr_SetFromErrnoWithFilenameObject14984833
Ref: 4c9514984833
Ref: c-api/exceptions c PyErr_SetFromErrnoWithFilenameObjects14985376
Ref: 4c9614985376
Ref: c-api/exceptions c PyErr_SetFromErrnoWithFilename14985848
Ref: 182414985848
Ref: c-api/exceptions c PyErr_SetFromWindowsErr14986239
Ref: 4c9714986239
Ref: c-api/exceptions c PyErr_SetExcFromWindowsErr14987140
Ref: 4c9214987140
Ref: c-api/exceptions c PyErr_SetFromWindowsErrWithFilename14987525
Ref: 182614987525
Ref: c-api/exceptions c PyErr_SetExcFromWindowsErrWithFilenameObject14988166
Ref: 4c9314988166
Ref: c-api/exceptions c PyErr_SetExcFromWindowsErrWithFilenameObjects14988759
Ref: 4c9414988759
Ref: c-api/exceptions c PyErr_SetExcFromWindowsErrWithFilename14989228
Ref: 182514989228
Ref: c-api/exceptions c PyErr_SetImportError14989669
Ref: d6614989669
Ref: c-api/exceptions c PyErr_SetImportErrorSubclass14990189
Ref: d3e14990189
Ref: c-api/exceptions c PyErr_SyntaxLocationObject14990613
Ref: 4ead14990613
Ref: c-api/exceptions c PyErr_RangedSyntaxLocationObject14991018
Ref: 4eae14991018
Ref: c-api/exceptions c PyErr_SyntaxLocationEx14991367
Ref: 4c9b14991367
Ref: c-api/exceptions c PyErr_SyntaxLocation14991725
Ref: 4c9a14991725
Ref: c-api/exceptions c PyErr_BadInternalCall14991953
Ref: 4c8e14991953
Ref: c-api/exceptions c PyErr_ProgramTextObject14992294
Ref: 4eaf14992294
Ref: c-api/exceptions c PyErr_ProgramText14992684
Ref: 4c9114992684
Node: Issuing warnings14993042
Ref: c-api/exceptions issuing-warnings14993177
Ref: 4eb014993177
Ref: c-api/exceptions c PyErr_WarnEx14994073
Ref: 149b14994073
Ref: c-api/exceptions c PyErr_WarnExplicitObject14995273
Ref: 4eb214995273
Ref: c-api/exceptions c PyErr_WarnExplicit14995817
Ref: 182c14995817
Ref: c-api/exceptions c PyErr_WarnFormat14996250
Ref: 4c9c14996250
Ref: c-api/exceptions c PyErr_WarnExplicitFormat14996610
Ref: 4eb314996610
Ref: c-api/exceptions c PyErr_ResourceWarning14996997
Ref: d3f14996997
Node: Querying the error indicator14997379
Ref: c-api/exceptions querying-the-error-indicator14997514
Ref: 4eb414997514
Ref: c-api/exceptions c PyErr_Occurred14997585
Ref: 1a5514997585
Ref: c-api/exceptions c PyErr_ExceptionMatches14998464
Ref: 4c1014998464
Ref: c-api/exceptions c PyErr_GivenExceptionMatches14998788
Ref: 4c8f14998788
Ref: c-api/exceptions c PyErr_GetRaisedException14999225
Ref: 3f714999225
Ref: c-api/exceptions c PyErr_SetRaisedException15000069
Ref: 3fa15000069
Ref: c-api/exceptions c PyErr_Fetch15000435
Ref: 3f615000435
Ref: c-api/exceptions c PyErr_Restore15001495
Ref: 3f915001495
Ref: c-api/exceptions c PyErr_NormalizeException15002661
Ref: 3f815002661
Ref: c-api/exceptions c PyErr_GetHandledException15003724
Ref: 77215003724
Ref: c-api/exceptions c PyErr_SetHandledException15004529
Ref: 77315004529
Ref: c-api/exceptions c PyErr_GetExcInfo15005202
Ref: 77515005202
Ref: c-api/exceptions c PyErr_SetExcInfo15006171
Ref: 77415006171
Node: Signal Handling<2>15007348
Ref: c-api/exceptions signal-handling15007484
Ref: 4eb515007484
Ref: c-api/exceptions c PyErr_CheckSignals15007529
Ref: 46a15007529
Ref: c-api/exceptions c PyErr_SetInterrupt15009082
Ref: 4c9815009082
Ref: c-api/exceptions c PyErr_SetInterruptEx15009432
Ref: 8a515009432
Ref: c-api/exceptions c PySignal_SetWakeupFd15010511
Ref: 142915010511
Node: Exception Classes15011181
Ref: c-api/exceptions exception-classes15011306
Ref: 4eb615011306
Ref: c-api/exceptions c PyErr_NewException15011355
Ref: 12b015011355
Ref: c-api/exceptions c PyErr_NewExceptionWithDoc15012361
Ref: 12af15012361
Ref: c-api/exceptions c PyExceptionClass_Check15012824
Ref: 4eb715012824
Ref: c-api/exceptions c PyExceptionClass_Name15012988
Ref: a7415012988
Node: Exception Objects15013179
Ref: c-api/exceptions exception-objects15013311
Ref: 4eb815013311
Ref: c-api/exceptions c PyExceptionInstance_Check15013360
Ref: 4eb915013360
Ref: c-api/exceptions c PyExceptionInstance_Class15013546
Ref: 4eba15013546
Ref: c-api/exceptions c PyException_GetTraceback15013635
Ref: 4ce315013635
Ref: c-api/exceptions c PyException_SetTraceback15014029
Ref: 1b7a15014029
Ref: c-api/exceptions c PyException_GetContext15014252
Ref: 4ce215014252
Ref: c-api/exceptions c PyException_SetContext15014710
Ref: 4ce515014710
Ref: c-api/exceptions c PyException_GetCause15015048
Ref: 4ce115015048
Ref: c-api/exceptions c PyException_SetCause15015446
Ref: 4ce415015446
Ref: c-api/exceptions c PyException_GetArgs15015918
Ref: 56d15015918
Ref: c-api/exceptions c PyException_SetArgs15016135
Ref: 56e15016135
Ref: c-api/exceptions c PyUnstable_Exc_PrepReraiseStar15016327
Ref: 4ebb15016327
Node: Unicode Exception Objects15017242
Ref: c-api/exceptions unicode-exception-objects15017374
Ref: 4ebc15017374
Ref: c-api/exceptions unicodeexceptions15017374
Ref: 4ebd15017374
Ref: c-api/exceptions c PyUnicodeDecodeError_Create15017521
Ref: 4da515017521
Ref: c-api/exceptions c PyUnicodeDecodeError_GetEncoding15017994
Ref: 4da615017994
Ref: c-api/exceptions c PyUnicodeEncodeError_GetEncoding15018091
Ref: 4dae15018091
Ref: c-api/exceptions c PyUnicodeDecodeError_GetObject15018337
Ref: 4da815018337
Ref: c-api/exceptions c PyUnicodeEncodeError_GetObject15018432
Ref: 4db015018432
Ref: c-api/exceptions c PyUnicodeTranslateError_GetObject15018527
Ref: 4db815018527
Ref: c-api/exceptions c PyUnicodeDecodeError_GetStart15018767
Ref: 4daa15018767
Ref: c-api/exceptions c PyUnicodeEncodeError_GetStart15018862
Ref: 4db215018862
Ref: c-api/exceptions c PyUnicodeTranslateError_GetStart15018957
Ref: 4dba15018957
Ref: c-api/exceptions c PyUnicodeDecodeError_SetStart15019276
Ref: 4dad15019276
Ref: c-api/exceptions c PyUnicodeEncodeError_SetStart15019370
Ref: 4db515019370
Ref: c-api/exceptions c PyUnicodeTranslateError_SetStart15019464
Ref: 4dbd15019464
Ref: c-api/exceptions c PyUnicodeDecodeError_GetEnd15019733
Ref: 4da715019733
Ref: c-api/exceptions c PyUnicodeEncodeError_GetEnd15019824
Ref: 4daf15019824
Ref: c-api/exceptions c PyUnicodeTranslateError_GetEnd15019915
Ref: 4db715019915
Ref: c-api/exceptions c PyUnicodeDecodeError_SetEnd15020224
Ref: 4dab15020224
Ref: c-api/exceptions c PyUnicodeEncodeError_SetEnd15020314
Ref: 4db315020314
Ref: c-api/exceptions c PyUnicodeTranslateError_SetEnd15020404
Ref: 4dbb15020404
Ref: c-api/exceptions c PyUnicodeDecodeError_GetReason15020665
Ref: 4da915020665
Ref: c-api/exceptions c PyUnicodeEncodeError_GetReason15020760
Ref: 4db115020760
Ref: c-api/exceptions c PyUnicodeTranslateError_GetReason15020855
Ref: 4db915020855
Ref: c-api/exceptions c PyUnicodeDecodeError_SetReason15021095
Ref: 4dac15021095
Ref: c-api/exceptions c PyUnicodeEncodeError_SetReason15021192
Ref: 4db415021192
Ref: c-api/exceptions c PyUnicodeTranslateError_SetReason15021289
Ref: 4dbc15021289
Node: Recursion Control15021563
Ref: c-api/exceptions recursion15021705
Ref: 4ebe15021705
Ref: c-api/exceptions recursion-control15021705
Ref: 4ebf15021705
Ref: c-api/exceptions c Py_EnterRecursiveCall15022137
Ref: 97d15022137
Ref: c-api/exceptions c Py_LeaveRecursiveCall15023056
Ref: 97e15023056
Ref: c-api/exceptions c Py_ReprEnter15023755
Ref: 4df515023755
Ref: c-api/exceptions c Py_ReprLeave15024561
Ref: 4df615024561
Ref: c-api/exceptions c Py_GetRecursionLimit15024788
Ref: 4df015024788
Ref: c-api/exceptions c Py_SetRecursionLimit15025243
Ref: 4df715025243
Node: Exception and warning types15025558
Ref: c-api/exceptions exception-and-warning-types15025685
Ref: 4ec015025685
Ref: c-api/exceptions standardexceptions15025685
Ref: 4ec115025685
Node: Exception types15026100
Ref: c-api/exceptions exception-types15026203
Ref: 4ec215026203
Ref: c-api/exceptions c PyExc_BaseException15026580
Ref: 4ca415026580
Ref: c-api/exceptions c PyExc_BaseExceptionGroup15026761
Ref: 4ca515026761
Ref: c-api/exceptions c PyExc_Exception15026972
Ref: 4cb315026972
Ref: c-api/exceptions c PyExc_ArithmeticError15027149
Ref: 4ca115027149
Ref: c-api/exceptions c PyExc_AssertionError15027333
Ref: 4ca215027333
Ref: c-api/exceptions c PyExc_AttributeError15027515
Ref: 4ca315027515
Ref: c-api/exceptions c PyExc_BlockingIOError15027697
Ref: 4ca615027697
Ref: c-api/exceptions c PyExc_BrokenPipeError15027905
Ref: 4ca715027905
Ref: c-api/exceptions c PyExc_BufferError15028113
Ref: 4ca815028113
Ref: c-api/exceptions c PyExc_ChildProcessError15028293
Ref: 4caa15028293
Ref: c-api/exceptions c PyExc_ConnectionAbortedError15028503
Ref: 4cab15028503
Ref: c-api/exceptions c PyExc_ConnectionError15028718
Ref: 4cac15028718
Ref: c-api/exceptions c PyExc_ConnectionRefusedError15028925
Ref: 4cad15028925
Ref: c-api/exceptions c PyExc_ConnectionResetError15029140
Ref: 4cae15029140
Ref: c-api/exceptions c PyExc_EOFError15029369
Ref: 4cb015029369
Ref: c-api/exceptions c PyExc_FileExistsError15029487
Ref: 4cb415029487
Ref: c-api/exceptions c PyExc_FileNotFoundError15029695
Ref: 4cb515029695
Ref: c-api/exceptions c PyExc_FloatingPointError15029904
Ref: 4cb615029904
Ref: c-api/exceptions c PyExc_GeneratorExit15030091
Ref: 4cb815030091
Ref: c-api/exceptions c PyExc_ImportError15030273
Ref: 4cba15030273
Ref: c-api/exceptions c PyExc_IndentationError15030452
Ref: 4cbc15030452
Ref: c-api/exceptions c PyExc_IndexError15030636
Ref: 4cbd15030636
Ref: c-api/exceptions c PyExc_InterruptedError15030815
Ref: 4cbe15030815
Ref: c-api/exceptions c PyExc_IsADirectoryError15031023
Ref: 4cbf15031023
Ref: c-api/exceptions c PyExc_KeyError15031249
Ref: 4cc015031249
Ref: c-api/exceptions c PyExc_KeyboardInterrupt15031366
Ref: 4cc115031366
Ref: c-api/exceptions c PyExc_LookupError15031551
Ref: 4cc215031551
Ref: c-api/exceptions c PyExc_MemoryError15031731
Ref: 4cc315031731
Ref: c-api/exceptions c PyExc_ModuleNotFoundError15031911
Ref: 4cc415031911
Ref: c-api/exceptions c PyExc_NameError15032122
Ref: 4cc515032122
Ref: c-api/exceptions c PyExc_NotADirectoryError15032299
Ref: 4cc615032299
Ref: c-api/exceptions c PyExc_NotImplementedError15032510
Ref: 4cc715032510
Ref: c-api/exceptions c PyExc_OSError15032712
Ref: 4b6515032712
Ref: c-api/exceptions c PyExc_OverflowError15032829
Ref: 4cc815032829
Ref: c-api/exceptions c PyExc_PermissionError15033010
Ref: 4cca15033010
Ref: c-api/exceptions c PyExc_ProcessLookupError15033217
Ref: 4ccb15033217
Ref: c-api/exceptions c PyExc_PythonFinalizationError15033428
Ref: 4ec315033428
Ref: c-api/exceptions c PyExc_RecursionError15033576
Ref: ee615033576
Ref: c-api/exceptions c PyExc_ReferenceError15033782
Ref: 4ccc15033782
Ref: c-api/exceptions c PyExc_RuntimeError15033965
Ref: 4cce15033965
Ref: c-api/exceptions c PyExc_StopAsyncIteration15034145
Ref: 4cd015034145
Ref: c-api/exceptions c PyExc_StopIteration15034356
Ref: 4cd115034356
Ref: c-api/exceptions c PyExc_SyntaxError15034537
Ref: 4cd215034537
Ref: c-api/exceptions c PyExc_SystemError15034716
Ref: 4cd415034716
Ref: c-api/exceptions c PyExc_SystemExit15034895
Ref: 4cd515034895
Ref: c-api/exceptions c PyExc_TabError15035089
Ref: 4cd615035089
Ref: c-api/exceptions c PyExc_TimeoutError15035206
Ref: 4cd715035206
Ref: c-api/exceptions c PyExc_TypeError15035410
Ref: 4b6415035410
Ref: c-api/exceptions c PyExc_UnboundLocalError15035587
Ref: 4cd815035587
Ref: c-api/exceptions c PyExc_UnicodeDecodeError15035773
Ref: 4cd915035773
Ref: c-api/exceptions c PyExc_UnicodeEncodeError15035959
Ref: 4cda15035959
Ref: c-api/exceptions c PyExc_UnicodeError15036145
Ref: 4cdb15036145
Ref: c-api/exceptions c PyExc_UnicodeTranslateError15036326
Ref: 4cdc15036326
Ref: c-api/exceptions c PyExc_ValueError15036516
Ref: 4b6615036516
Ref: c-api/exceptions c PyExc_ZeroDivisionError15036694
Ref: 4b6115036694
Ref: Exception types-Footnote-115037721
Node: OSError aliases15037763
Ref: c-api/exceptions oserror-aliases15037888
Ref: 4ec415037888
Ref: c-api/exceptions c PyExc_EnvironmentError15038454
Ref: 4cb215038454
Ref: c-api/exceptions c PyExc_IOError15038634
Ref: 4cb915038634
Ref: c-api/exceptions c PyExc_WindowsError15038805
Ref: 4ce015038805
Ref: c-api/exceptions win15039084
Ref: 4ec515039084
Node: Warning types15039240
Ref: c-api/exceptions standardwarningcategories15039341
Ref: 4eb115039341
Ref: c-api/exceptions warning-types15039341
Ref: 4ec615039341
Ref: c-api/exceptions c PyExc_Warning15039729
Ref: 4cdf15039729
Ref: c-api/exceptions c PyExc_BytesWarning15039847
Ref: 4ca915039847
Ref: c-api/exceptions c PyExc_DeprecationWarning15040027
Ref: 4caf15040027
Ref: c-api/exceptions c PyExc_EncodingWarning15040213
Ref: 4cb115040213
Ref: c-api/exceptions c PyExc_FutureWarning15040422
Ref: 4cb715040422
Ref: c-api/exceptions c PyExc_ImportWarning15040603
Ref: 4cbb15040603
Ref: c-api/exceptions c PyExc_PendingDeprecationWarning15040784
Ref: 4cc915040784
Ref: c-api/exceptions c PyExc_ResourceWarning15040977
Ref: 4ccd15040977
Ref: c-api/exceptions c PyExc_RuntimeWarning15041184
Ref: 4ccf15041184
Ref: c-api/exceptions c PyExc_SyntaxWarning15041366
Ref: 4cd315041366
Ref: c-api/exceptions c PyExc_UnicodeWarning15041547
Ref: 4cdd15041547
Ref: c-api/exceptions c PyExc_UserWarning15041730
Ref: 4cde15041730
Node: Tracebacks15041991
Ref: c-api/exceptions tracebacks15042092
Ref: 4ec715042092
Ref: c-api/exceptions c PyTraceBack_Type15042129
Ref: 4d9c15042129
Ref: c-api/exceptions c PyTraceBack_Check15042352
Ref: 4ec815042352
Ref: c-api/exceptions c PyTraceBack_Here15042523
Ref: 4d9a15042523
Ref: c-api/exceptions c PyTraceBack_Print15042956
Ref: 4d9b15042956
Node: Utilities<2>15043224
Ref: c-api/utilities doc15043360
Ref: 4ec915043360
Ref: c-api/utilities id115043360
Ref: 4eca15043360
Ref: c-api/utilities translation-repo15043360
Ref: 4ecb15043360
Ref: c-api/utilities utilities15043360
Ref: 4ecc15043360
Node: Operating System Utilities15044011
Ref: c-api/sys doc15044111
Ref: 4ecd15044111
Ref: c-api/sys operating-system-utilities15044111
Ref: 4ece15044111
Ref: c-api/sys os15044111
Ref: 4ecf15044111
Ref: c-api/sys c PyOS_FSPath15044178
Ref: d4015044178
Ref: c-api/sys c Py_FdIsInteractive15044801
Ref: 4ed015044801
Ref: c-api/sys c PyOS_BeforeFork15045346
Ref: bde15045346
Ref: c-api/sys c PyOS_AfterFork_Parent15045968
Ref: bdf15045968
Ref: c-api/sys c PyOS_AfterFork_Child15046681
Ref: 3fe15046681
Ref: c-api/sys c PyOS_AfterFork15047676
Ref: 3fd15047676
Ref: c-api/sys c PyOS_CheckStack15048161
Ref: 194715048161
Ref: c-api/sys c PyOS_sighandler_t15048670
Ref: 4d4915048670
Ref: c-api/sys c PyOS_getsig15048765
Ref: 158e15048765
Ref: c-api/sys c PyOS_setsig15049051
Ref: 158f15049051
Ref: c-api/sys c PyOS_InterruptOccurred15049403
Ref: 1ae915049403
Ref: c-api/sys c Py_DecodeLocale15050131
Ref: be615050131
Ref: c-api/sys c Py_EncodeLocale15052450
Ref: be715052450
Node: System Functions15054214
Ref: c-api/sys system-functions15054338
Ref: 4ed215054338
Ref: c-api/sys systemfunctions15054338
Ref: 4ed315054338
Ref: c-api/sys c PySys_GetObject15054632
Ref: 38c15054632
Ref: c-api/sys c PySys_SetObject15054918
Ref: 4d8715054918
Ref: c-api/sys c PySys_ResetWarnOptions15055220
Ref: 3b215055220
Ref: c-api/sys c PySys_WriteStdout15055585
Ref: 4d8915055585
Ref: c-api/sys c PySys_WriteStderr15056499
Ref: 4d8815056499
Ref: c-api/sys c PySys_FormatStdout15056712
Ref: 4d8515056712
Ref: c-api/sys c PySys_FormatStderr15057028
Ref: 4d8415057028
Ref: c-api/sys c PySys_GetXOptions15057271
Ref: 4d8615057271
Ref: c-api/sys c PySys_Audit15057629
Ref: 37215057629
Ref: c-api/sys c PySys_AuditTuple15058964
Ref: 37115058964
Ref: c-api/sys c PySys_AddAuditHook15059302
Ref: 441f15059302
Ref: c-api/sys c Py_AuditHookFunction15060923
Ref: 4ed415060923
Ref: System Functions-Footnote-115061428
Node: Process Control15061470
Ref: c-api/sys process-control15061588
Ref: 4ed615061588
Ref: c-api/sys processcontrol15061588
Ref: 4ed715061588
Ref: c-api/sys c Py_FatalError15061633
Ref: 98d15061633
Ref: c-api/sys c Py_Exit15062408
Ref: d7815062408
Ref: c-api/sys c Py_AtExit15062799
Ref: 4de815062799
Node: Importing Modules<2>15063606
Ref: c-api/import doc15063732
Ref: 4ed815063732
Ref: c-api/import importing15063732
Ref: 4ed915063732
Ref: c-api/import importing-modules15063732
Ref: 4eda15063732
Ref: c-api/import translation-repo15063732
Ref: 4edb15063732
Ref: c-api/import c PyImport_ImportModule15063781
Ref: 3c115063781
Ref: c-api/import c PyImport_ImportModuleNoBlock15064094
Ref: 3c015064094
Ref: c-api/import c PyImport_ImportModuleEx15064761
Ref: 11e915064761
Ref: c-api/import c PyImport_ImportModuleLevelObject15065511
Ref: 4cfb15065511
Ref: c-api/import c PyImport_ImportModuleLevel15066341
Ref: 11e815066341
Ref: c-api/import c PyImport_Import15066813
Ref: 144a15066813
Ref: c-api/import c PyImport_ReloadModule15067389
Ref: 4cfc15067389
Ref: c-api/import c PyImport_AddModuleRef15067716
Ref: 35915067716
Ref: c-api/import c PyImport_AddModuleObject15068715
Ref: 4cf215068715
Ref: c-api/import c PyImport_AddModule15069086
Ref: 35a15069086
Ref: c-api/import c PyImport_ExecCodeModule15069354
Ref: 4cf315069354
Ref: c-api/import c PyImport_ExecCodeModuleEx15071357
Ref: 4cf415071357
Ref: c-api/import c PyImport_ExecCodeModuleObject15071795
Ref: 4cf515071795
Ref: c-api/import c PyImport_ExecCodeModuleWithPathnames15072441
Ref: 4cf615072441
Ref: c-api/import c PyImport_GetMagicNumber15073200
Ref: 11e715073200
Ref: c-api/import c PyImport_GetMagicTag15073593
Ref: 4cf715073593
Ref: c-api/import c PyImport_GetModuleDict15073941
Ref: 4cf815073941
Ref: c-api/import c PyImport_GetModule15074234
Ref: bd115074234
Ref: c-api/import c PyImport_GetImporter15074669
Ref: 182315074669
Ref: c-api/import c PyImport_ImportFrozenModuleObject15075392
Ref: 4cfa15075392
Ref: c-api/import c PyImport_ImportFrozenModule15076030
Ref: 4cf915076030
Ref: c-api/import c _frozen15076280
Ref: 77815076280
Ref: c-api/import c PyImport_FrozenModules15076912
Ref: 301815076912
Ref: c-api/import c PyImport_AppendInittab15077327
Ref: 18bf15077327
Ref: c-api/import c _inittab15077909
Ref: 4edc15077909
Ref: c-api/import c _inittab name15078239
Ref: 4edd15078239
Ref: c-api/import c _inittab initfunc15078332
Ref: 4ede15078332
Ref: c-api/import c PyImport_ExtendInittab15078478
Ref: 18c015078478
Ref: c-api/import c PyImport_Inittab15079253
Ref: 18be15079253
Ref: Importing Modules<2>-Footnote-115079550
Node: Data marshalling support15079592
Ref: c-api/marshal doc15079740
Ref: 4edf15079740
Ref: c-api/marshal data-marshalling-support15079740
Ref: 4ee015079740
Ref: c-api/marshal marshalling-utils15079740
Ref: 4ee115079740
Ref: c-api/marshal translation-repo15079740
Ref: 4ee215079740
Ref: c-api/marshal c PyMarshal_WriteLongToFile15080487
Ref: 79915080487
Ref: c-api/marshal c PyMarshal_WriteObjectToFile15080924
Ref: 79a15080924
Ref: c-api/marshal c PyMarshal_WriteObjectToString15081252
Ref: 79c15081252
Ref: c-api/marshal c PyMarshal_ReadLongFromFile15081591
Ref: 4ee315081591
Ref: c-api/marshal c PyMarshal_ReadShortFromFile15081930
Ref: 4ee415081930
Ref: c-api/marshal c PyMarshal_ReadObjectFromFile15082272
Ref: 4ee515082272
Ref: c-api/marshal c PyMarshal_ReadLastObjectFromFile15082633
Ref: 4ee615082633
Ref: c-api/marshal c PyMarshal_ReadObjectFromString15083426
Ref: 79b15083426
Node: Parsing arguments and building values15083847
Ref: c-api/arg doc15084007
Ref: 4ee715084007
Ref: c-api/arg arg-parsing15084007
Ref: 8b015084007
Ref: c-api/arg parsing-arguments-and-building-values15084007
Ref: 4ee815084007
Ref: c-api/arg translation-repo15084007
Ref: 4ee915084007
Node: Parsing arguments<2>15084678
Ref: c-api/arg parsing-arguments15084796
Ref: 4eea15084796
Node: Strings and buffers15085526
Ref: c-api/arg arg-parsing-string-and-buffers15085621
Ref: 38e15085621
Ref: c-api/arg strings-and-buffers15085621
Ref: 4eeb15085621
Ref: c-api/arg c-arg-borrowed-buffer15086900
Ref: 4eec15086900
Node: Numbers<2>15096229
Ref: c-api/arg numbers15096346
Ref: 4eed15096346
Node: Other objects15099023
Ref: c-api/arg other-objects15099134
Ref: 4eef15099134
Ref: c-api/arg o-ampersand15099952
Ref: 4ef015099952
Ref: c-api/arg c Py_CLEANUP_SUPPORTED15100742
Ref: 4ef115100742
Node: API Functions15104247
Ref: c-api/arg api-functions15104339
Ref: 4ef215104339
Ref: c-api/arg c PyArg_ParseTuple15104384
Ref: 57415104384
Ref: c-api/arg c PyArg_VaParse15104721
Ref: 4c2615104721
Ref: c-api/arg c PyArg_ParseTupleAndKeywords15104993
Ref: 38615104993
Ref: c-api/arg c PyArg_VaParseTupleAndKeywords15106095
Ref: 38715106095
Ref: c-api/arg c PyArg_ValidateKeywordArguments15106441
Ref: 4c2715106441
Ref: c-api/arg c PyArg_Parse15106783
Ref: 1b7415106783
Ref: c-api/arg c PyArg_UnpackTuple15107465
Ref: 155615107465
Ref: c-api/arg c PY_CXX_CONST15109447
Ref: 38815109447
Node: Building values15109866
Ref: c-api/arg building-values15109984
Ref: 4ef315109984
Ref: c-api/arg c Py_BuildValue15110033
Ref: 8af15110033
Ref: c-api/arg capi-py-buildvalue-format-k15114758
Ref: 165915114758
Ref: c-api/arg c Py_VaBuildValue15117595
Ref: 4e0915117595
Node: String conversion and formatting15117899
Ref: c-api/conversion doc15118074
Ref: 4ef415118074
Ref: c-api/conversion string-conversion15118074
Ref: 4ef515118074
Ref: c-api/conversion string-conversion-and-formatting15118074
Ref: 4ef615118074
Ref: c-api/conversion translation-repo15118074
Ref: 4ef715118074
Ref: c-api/conversion c PyOS_snprintf15118215
Ref: 155915118215
Ref: c-api/conversion c PyOS_vsnprintf15118517
Ref: 155a15118517
Ref: c-api/conversion c PyOS_strtoul15120249
Ref: 4d4b15120249
Ref: c-api/conversion c PyOS_strtol15121279
Ref: 4d4a15121279
Ref: c-api/conversion c PyOS_string_to_double15121796
Ref: 12dc15121796
Ref: c-api/conversion c PyOS_double_to_string15123555
Ref: 4d4815123555
Ref: c-api/conversion c Py_DTSF_SIGN15124166
Ref: 4ef815124166
Ref: c-api/conversion c Py_DTSF_ADD_DOT_015124308
Ref: 4ef915124308
Ref: c-api/conversion c Py_DTSF_ALT15124419
Ref: 4efa15124419
Ref: c-api/conversion c Py_DTSF_NO_NEG_015124604
Ref: 4efb15124604
Ref: c-api/conversion c Py_DTST_FINITE15125221
Ref: 4efc15125221
Ref: c-api/conversion c Py_DTST_INFINITE15125419
Ref: 4efd15125419
Ref: c-api/conversion c Py_DTST_NAN15125612
Ref: 4efe15125612
Ref: c-api/conversion c PyOS_mystricmp15125966
Ref: 1ae215125966
Ref: c-api/conversion c PyOS_mystrnicmp15126038
Ref: 1ae115126038
Ref: c-api/conversion c PyOS_stricmp15126830
Ref: 4eff15126830
Ref: c-api/conversion c PyOS_strnicmp15126900
Ref: 4f0015126900
Ref: String conversion and formatting-Footnote-115127307
Ref: String conversion and formatting-Footnote-215127355
Ref: String conversion and formatting-Footnote-315127404
Ref: String conversion and formatting-Footnote-415127451
Node: Character classification and conversion15127497
Ref: c-api/conversion character-classification-and-conversion15127645
Ref: 4f0115127645
Ref: c-api/conversion c Py_ISALNUM15127923
Ref: 139d15127923
Ref: c-api/conversion c Py_ISALPHA15128021
Ref: 139e15128021
Ref: c-api/conversion c Py_ISDIGIT15128148
Ref: 139f15128148
Ref: c-api/conversion c Py_ISLOWER15128248
Ref: 13a015128248
Ref: c-api/conversion c Py_ISUPPER15128362
Ref: 13a215128362
Ref: c-api/conversion c Py_ISSPACE15128477
Ref: 13a115128477
Ref: c-api/conversion c Py_ISXDIGIT15128644
Ref: 13a315128644
Ref: c-api/conversion c Py_TOLOWER15128780
Ref: 13a415128780
Ref: c-api/conversion c Py_TOUPPER15128869
Ref: 13a515128869
Node: PyHash API15128958
Ref: c-api/hash doc15129084
Ref: 4f0215129084
Ref: c-api/hash pyhash-api15129084
Ref: 4f0315129084
Ref: c-api/hash translation-repo15129084
Ref: 4f0415129084
Ref: c-api/hash c Py_hash_t15129216
Ref: 12aa15129216
Ref: c-api/hash c Py_uhash_t15129311
Ref: 4f0515129311
Ref: c-api/hash c Py_HASH_ALGORITHM15129409
Ref: 4f0615129409
Ref: c-api/hash c Py_HASH_FNV15129680
Ref: 4f0715129680
Ref: c-api/hash c Py_HASH_SIPHASH2415129705
Ref: 4f0815129705
Ref: c-api/hash c Py_HASH_SIPHASH1315129736
Ref: 4f0915129736
Ref: c-api/hash c Py_HASH_CUTOFF15130136
Ref: 4f0a15130136
Ref: c-api/hash c PyHASH_MODULUS15130823
Ref: 177c15130823
Ref: c-api/hash c PyHASH_BITS15131038
Ref: 177d15131038
Ref: c-api/hash c PyHASH_MULTIPLIER15131162
Ref: 172a15131162
Ref: c-api/hash c PyHASH_INF15131287
Ref: 177e15131287
Ref: c-api/hash c PyHASH_IMAG15131467
Ref: 177f15131467
Ref: c-api/hash c PyHash_FuncDef15131664
Ref: 4f0b15131664
Ref: c-api/hash c PyHash_FuncDef hash15131769
Ref: 4f0d15131769
Ref: c-api/hash c PyHash_FuncDef name15131904
Ref: 4f0e15131904
Ref: c-api/hash c PyHash_FuncDef hash_bits15132087
Ref: 4f0f15132087
Ref: c-api/hash c PyHash_FuncDef seed_bits15132271
Ref: 4f1015132271
Ref: c-api/hash c PyHash_GetFuncDef15132470
Ref: 4f0c15132470
Ref: c-api/hash c Py_HashPointer15132704
Ref: 36b15132704
Ref: c-api/hash c PyObject_GenericHash15133013
Ref: 36a15133013
Ref: PyHash API-Footnote-115133431
Ref: PyHash API-Footnote-215133484
Node: Reflection15133526
Ref: c-api/reflection doc15133649
Ref: 4f1115133649
Ref: c-api/reflection id115133649
Ref: 4f1215133649
Ref: c-api/reflection reflection15133649
Ref: 4f1315133649
Ref: c-api/reflection translation-repo15133649
Ref: 4f1415133649
Ref: c-api/reflection c PyEval_GetBuiltins15133686
Ref: 35215133686
Ref: c-api/reflection c PyEval_GetLocals15134087
Ref: 35615134087
Ref: c-api/reflection c PyEval_GetGlobals15135633
Ref: 35415135633
Ref: c-api/reflection c PyEval_GetFrame15136010
Ref: 18dc15136010
Ref: c-api/reflection c PyEval_GetFrameBuiltins15136318
Ref: 35115136318
Ref: c-api/reflection c PyEval_GetFrameLocals15136670
Ref: 35515136670
Ref: c-api/reflection c PyEval_GetFrameGlobals15137296
Ref: 35315137296
Ref: c-api/reflection c PyEval_GetFuncName15137697
Ref: 4c9f15137697
Ref: c-api/reflection c PyEval_GetFuncDesc15137920
Ref: 4c9e15137920
Ref: Reflection-Footnote-115138372
Node: Codec registry and support functions15138414
Ref: c-api/codec doc15138539
Ref: 4f1515138539
Ref: c-api/codec codec-registry15138539
Ref: d5d15138539
Ref: c-api/codec codec-registry-and-support-functions15138539
Ref: 4f1615138539
Ref: c-api/codec translation-repo15138539
Ref: 4f1715138539
Ref: c-api/codec c PyCodec_Register15138628
Ref: 4c6815138628
Ref: c-api/codec c PyCodec_Unregister15138950
Ref: 89e15138950
Ref: c-api/codec c PyCodec_KnownEncoding15139314
Ref: 4c6615139314
Ref: c-api/codec c PyCodec_Encode15139566
Ref: 40315139566
Ref: c-api/codec c PyCodec_Decode15140102
Ref: 40215140102
Node: Codec lookup API15140750
Ref: c-api/codec codec-lookup-api15140896
Ref: 4f1815140896
Ref: c-api/codec c PyCodec_Encoder15141216
Ref: 4c6215141216
Ref: c-api/codec c PyCodec_Decoder15141434
Ref: 4c6115141434
Ref: c-api/codec c PyCodec_IncrementalEncoder15141651
Ref: 4c6515141651
Ref: c-api/codec c PyCodec_IncrementalDecoder15141927
Ref: 4c6415141927
Ref: c-api/codec c PyCodec_StreamReader15142203
Ref: 4c6b15142203
Ref: c-api/codec c PyCodec_StreamWriter15142494
Ref: 4c6c15142494
Node: Registry API for Unicode encoding error handlers15142785
Ref: c-api/codec registry-api-for-unicode-encoding-error-handlers15142963
Ref: 4f1915142963
Ref: c-api/codec c PyCodec_RegisterError15143080
Ref: 4c6915143080
Ref: c-api/codec c PyCodec_LookupError15144210
Ref: 4c6715144210
Ref: c-api/codec c PyCodec_StrictErrors15144579
Ref: 4c6d15144579
Ref: c-api/codec c PyCodec_IgnoreErrors15144770
Ref: 4c6315144770
Ref: c-api/codec c PyCodec_ReplaceErrors15144989
Ref: 4c6a15144989
Ref: c-api/codec c PyCodec_XMLCharRefReplaceErrors15145219
Ref: 4c6e15145219
Ref: c-api/codec c PyCodec_BackslashReplaceErrors15145465
Ref: 4c6015145465
Ref: c-api/codec c PyCodec_NameReplaceErrors15145737
Ref: ee315145737
Node: Codec utility variables15146021
Ref: c-api/codec codec-utility-variables15146174
Ref: 4f1a15146174
Ref: c-api/codec c Py_hexdigits15146241
Ref: 4f1b15146241
Node: PyTime C API15146411
Ref: c-api/time doc15146547
Ref: 15a15146547
Ref: c-api/time c-api-time15146547
Ref: 32d15146547
Ref: c-api/time pytime-c-api15146547
Ref: 4f1c15146547
Ref: c-api/time translation-repo15146547
Ref: 4f1d15146547
Node: Types<2>15146902
Ref: c-api/time types15146983
Ref: 4f1f15146983
Ref: c-api/time c PyTime_t15147014
Ref: 32e15147014
Ref: c-api/time c PyTime_MIN15147539
Ref: 32f15147539
Ref: c-api/time c PyTime_MAX15147632
Ref: 33015147632
Node: Clock Functions15147725
Ref: c-api/time clock-functions15147834
Ref: 4f2015147834
Ref: c-api/time c PyTime_Monotonic15148548
Ref: 33215148548
Ref: c-api/time c PyTime_PerfCounter15148713
Ref: 33415148713
Ref: c-api/time c PyTime_Time15148887
Ref: 33615148887
Node: Raw Clock Functions15149048
Ref: c-api/time raw-clock-functions15149169
Ref: 4f2115149169
Ref: c-api/time c PyTime_MonotonicRaw15149657
Ref: 33315149657
Ref: c-api/time c PyTime_PerfCounterRaw15149845
Ref: 33515149845
Ref: c-api/time c PyTime_TimeRaw15150037
Ref: 33715150037
Node: Conversion functions15150215
Ref: c-api/time conversion-functions15150312
Ref: 4f2215150312
Ref: c-api/time c PyTime_AsSecondsDouble15150373
Ref: 33115150373
Node: Support for Perf Maps15150594
Ref: c-api/perfmaps doc15150685
Ref: 4f2315150685
Ref: c-api/perfmaps perfmaps15150685
Ref: 4f2415150685
Ref: c-api/perfmaps support-for-perf-maps15150685
Ref: 4f2515150685
Ref: c-api/perfmaps translation-repo15150685
Ref: 4f2615150685
Ref: c-api/perfmaps c PyUnstable_PerfMapState_Init15151356
Ref: 184b15151356
Ref: c-api/perfmaps c PyUnstable_WritePerfMapEntry15152181
Ref: 184a15152181
Ref: c-api/perfmaps c PyUnstable_PerfMapState_Fini15152959
Ref: 184c15152959
Ref: Support for Perf Maps-Footnote-115153513
Ref: Support for Perf Maps-Footnote-215153570
Node: Abstract Objects Layer15153694
Ref: c-api/abstract doc15153834
Ref: 4f2715153834
Ref: c-api/abstract abstract15153834
Ref: 4bbd15153834
Ref: c-api/abstract abstract-objects-layer15153834
Ref: 4f2815153834
Ref: c-api/abstract translation-repo15153834
Ref: 4f2915153834
Node: Object Protocol15154539
Ref: c-api/object doc15154635
Ref: 4f2a15154635
Ref: c-api/object object15154635
Ref: 4f2b15154635
Ref: c-api/object object-protocol15154635
Ref: 4f2c15154635
Ref: c-api/object c Py_GetConstant15154680
Ref: 35715154680
Ref: c-api/object c Py_CONSTANT_NONE15155350
Ref: 4f2d15155350
Ref: c-api/object c Py_CONSTANT_FALSE15155554
Ref: 4f2e15155554
Ref: c-api/object c Py_CONSTANT_TRUE15155757
Ref: 4f2f15155757
Ref: c-api/object c Py_CONSTANT_ELLIPSIS15155964
Ref: 4f3015155964
Ref: c-api/object c Py_CONSTANT_NOT_IMPLEMENTED15156179
Ref: 4f3115156179
Ref: c-api/object c Py_CONSTANT_ZERO15156381
Ref: 4f3215156381
Ref: c-api/object c Py_CONSTANT_ONE15156574
Ref: 4f3315156574
Ref: c-api/object c Py_CONSTANT_EMPTY_STR15156774
Ref: 4f3415156774
Ref: c-api/object c Py_CONSTANT_EMPTY_BYTES15156971
Ref: 4f3515156971
Ref: c-api/object c Py_CONSTANT_EMPTY_TUPLE15157167
Ref: 4f3615157167
Ref: c-api/object c Py_GetConstantBorrowed15157492
Ref: 35815157492
Ref: c-api/object c Py_NotImplemented15158026
Ref: 4f3715158026
Ref: c-api/object c Py_RETURN_NOTIMPLEMENTED15158214
Ref: 160815158214
Ref: c-api/object c Py_PRINT_RAW15158449
Ref: 4f3815158449
Ref: c-api/object c PyObject_Print15158737
Ref: 16fa15158737
Ref: c-api/object c PyObject_HasAttrWithError15159119
Ref: 37d15159119
Ref: c-api/object c PyObject_HasAttrStringWithError15159500
Ref: 37f15159500
Ref: c-api/object c PyObject_HasAttr15159879
Ref: 37e15159879
Ref: c-api/object c PyObject_HasAttrString15160528
Ref: 38015160528
Ref: c-api/object c PyObject_GetAttr15161273
Ref: 34c15161273
Ref: c-api/object c PyObject_GetAttrString15161787
Ref: 34d15161787
Ref: c-api/object c PyObject_GetOptionalAttr15162286
Ref: 34a15162286
Ref: c-api/object c PyObject_GetOptionalAttrString15163000
Ref: 34b15163000
Ref: c-api/object c PyObject_GenericGetAttr15163399
Ref: 4d5415163399
Ref: c-api/object c PyObject_SetAttr15164078
Ref: 4d5d15164078
Ref: c-api/object c PyObject_SetAttrString15164663
Ref: 170a15164663
Ref: c-api/object c PyObject_GenericSetAttr15165594
Ref: 4d5515165594
Ref: c-api/object c PyObject_DelAttr15166295
Ref: 163f15166295
Ref: c-api/object c PyObject_DelAttrString15166600
Ref: 164015166600
Ref: c-api/object c PyObject_GenericGetDict15167402
Ref: 1aac15167402
Ref: c-api/object c PyObject_GenericSetDict15168144
Ref: 4d5615168144
Ref: c-api/object c _PyObject_GetDictPtr15168484
Ref: 4f3915168484
Ref: c-api/object c PyObject_RichCompare15168912
Ref: 4bbb15168912
Ref: c-api/object c PyObject_RichCompareBool15169638
Ref: 1b3515169638
Ref: c-api/object c PyObject_Format15170177
Ref: 4d5315170177
Ref: c-api/object c PyObject_Repr15170619
Ref: 106c15170619
Ref: c-api/object c PyObject_ASCII15171242
Ref: 4d4c15171242
Ref: c-api/object c PyObject_Str15171837
Ref: 106d15171837
Ref: c-api/object c PyObject_Bytes15172509
Ref: 4d4e15172509
Ref: c-api/object c PyObject_IsSubclass15173086
Ref: edb15173086
Ref: c-api/object c PyObject_IsInstance15174118
Ref: eda15174118
Ref: c-api/object c PyObject_Hash15175140
Ref: 40615175140
Ref: c-api/object c PyObject_HashNotImplemented15175548
Ref: 141315175548
Ref: c-api/object c PyObject_IsTrue15175973
Ref: 4d5915175973
Ref: c-api/object c PyObject_Not15176258
Ref: 4d5b15176258
Ref: c-api/object c PyObject_Type15176536
Ref: 4d5f15176536
Ref: c-api/object c PyObject_TypeCheck15177229
Ref: 1a5b15177229
Ref: c-api/object c PyObject_Size15177454
Ref: 4d5e15177454
Ref: c-api/object c PyObject_Length15177521
Ref: 4d5a15177521
Ref: c-api/object c PyObject_LengthHint15177888
Ref: 103f15177888
Ref: c-api/object c PyObject_GetItem15178349
Ref: 34815178349
Ref: c-api/object c PyObject_SetItem15178679
Ref: 4c0a15178679
Ref: c-api/object c PyObject_DelItem15179064
Ref: 4d5015179064
Ref: c-api/object c PyObject_DelItemString15179337
Ref: 4d5115179337
Ref: c-api/object c PyObject_Dir15179633
Ref: 4d5215179633
Ref: c-api/object c PyObject_GetIter15180225
Ref: 4d5815180225
Ref: c-api/object c PyObject_SelfIter15180652
Ref: 4d5c15180652
Ref: c-api/object c PyObject_GetAIter15180996
Ref: 4d5715180996
Ref: c-api/object c PyObject_GetTypeData15181554
Ref: 54c15181554
Ref: c-api/object c PyType_GetTypeDataSize15182026
Ref: 54d15182026
Ref: c-api/object c PyObject_GetItemData15182707
Ref: 54f15182707
Ref: c-api/object c PyObject_VisitManagedDict15183050
Ref: 36c15183050
Ref: c-api/object c PyObject_ClearManagedDict15183365
Ref: 36d15183365
Ref: Object Protocol-Footnote-115183676
Ref: Object Protocol-Footnote-215183718
Node: Call Protocol15183760
Ref: c-api/call doc15183880
Ref: 4f4015183880
Ref: c-api/call call15183880
Ref: 58615183880
Ref: c-api/call call-protocol15183880
Ref: 4f4115183880
Ref: c-api/call translation-repo15183880
Ref: 4f4215183880
Node: The tp_call Protocol15184105
Ref: c-api/call the-tp-call-protocol15184207
Ref: 4f4315184207
Node: The Vectorcall Protocol15184943
Ref: c-api/call the-vectorcall-protocol15185072
Ref: 4f4515185072
Ref: c-api/call vectorcall15185072
Ref: 55515185072
Ref: c-api/call c vectorcallfunc15186842
Ref: 55a15186842
Ref: c-api/call c PY_VECTORCALL_ARGUMENTS_OFFSET15187924
Ref: 56115187924
Ref: The Vectorcall Protocol-Footnote-115189060
Node: Recursion Control<2>15189102
Ref: c-api/call recursion-control15189213
Ref: 4f4715189213
Node: Vectorcall Support API15189625
Ref: c-api/call vectorcall-support-api15189736
Ref: 4f4815189736
Ref: c-api/call c PyVectorcall_NARGS15189799
Ref: 55815189799
Ref: c-api/call c PyVectorcall_Function15190260
Ref: 4f4915190260
Ref: c-api/call c PyVectorcall_Call15190809
Ref: 55915190809
Node: Object Calling API15191422
Ref: c-api/call capi-call15191547
Ref: 4f4415191547
Ref: c-api/call object-calling-api15191547
Ref: 4f4a15191547
Ref: c-api/call c PyObject_Call15196175
Ref: 39f15196175
Ref: c-api/call c PyObject_CallNoArgs15196863
Ref: 39e15196863
Ref: c-api/call c PyObject_CallOneArg15197345
Ref: 98215197345
Ref: c-api/call c PyObject_CallObject15197738
Ref: 4b7715197738
Ref: c-api/call c PyObject_CallFunction15198257
Ref: 3a115198257
Ref: c-api/call c PyObject_CallMethod15199113
Ref: 3a215199113
Ref: c-api/call c PyObject_CallFunctionObjArgs15200033
Ref: 4d4f15200033
Ref: c-api/call c PyObject_CallMethodObjArgs15200609
Ref: 1b8d15200609
Ref: c-api/call c PyObject_CallMethodNoArgs15201199
Ref: 4f4b15201199
Ref: c-api/call c PyObject_CallMethodOneArg15201590
Ref: 4f4c15201590
Ref: c-api/call c _PyObject_Vectorcall15202018
Ref: 4f4e15202018
Ref: c-api/call c PyObject_Vectorcall15202018
Ref: 55f15202018
Ref: c-api/call c PyObject_VectorcallDict15202797
Ref: 4f4d15202797
Ref: c-api/call c PyObject_VectorcallMethod15203509
Ref: 56015203509
Node: Call Support API15204631
Ref: c-api/call call-support-api15204724
Ref: 4f4f15204724
Ref: c-api/call c PyCallable_Check15204775
Ref: 4c5415204775
Node: Number Protocol15205019
Ref: c-api/number doc15205141
Ref: 4f5015205141
Ref: c-api/number number15205141
Ref: 4f5115205141
Ref: c-api/number number-protocol15205141
Ref: 4f5215205141
Ref: c-api/number translation-repo15205141
Ref: 4f5315205141
Ref: c-api/number c PyNumber_Check15205186
Ref: a7515205186
Ref: c-api/number c PyNumber_Add15205479
Ref: 4d2b15205479
Ref: c-api/number c PyNumber_Subtract15205794
Ref: 4d4515205794
Ref: c-api/number c PyNumber_Multiply15206120
Ref: 4d3e15206120
Ref: c-api/number c PyNumber_MatrixMultiply15206445
Ref: eea15206445
Ref: c-api/number c PyNumber_FloorDivide15206836
Ref: 4d2f15206836
Ref: c-api/number c PyNumber_TrueDivide15207158
Ref: 4d4615207158
Ref: c-api/number c PyNumber_Remainder15207773
Ref: 4d4315207773
Ref: c-api/number c PyNumber_Divmod15208098
Ref: 4d2e15208098
Ref: c-api/number c PyNumber_Power15208437
Ref: 4d4215208437
Ref: c-api/number c PyNumber_Negative15208955
Ref: 4d3f15208955
Ref: c-api/number c PyNumber_Positive15209236
Ref: 4d4115209236
Ref: c-api/number c PyNumber_Absolute15209501
Ref: 4d2a15209501
Ref: c-api/number c PyNumber_Invert15209786
Ref: 4d3c15209786
Ref: c-api/number c PyNumber_Lshift15210073
Ref: 4d3d15210073
Ref: c-api/number c PyNumber_Rshift15210409
Ref: 4d4415210409
Ref: c-api/number c PyNumber_And15210746
Ref: 4d2c15210746
Ref: c-api/number c PyNumber_Xor15211076
Ref: 4d4715211076
Ref: c-api/number c PyNumber_Or15211414
Ref: 4d4015211414
Ref: c-api/number c PyNumber_InPlaceAdd15211742
Ref: 4d3015211742
Ref: c-api/number c PyNumber_InPlaceSubtract15212120
Ref: 4d3915212120
Ref: c-api/number c PyNumber_InPlaceMultiply15212510
Ref: 4d3415212510
Ref: c-api/number c PyNumber_InPlaceMatrixMultiply15212899
Ref: eeb15212899
Ref: c-api/number c PyNumber_InPlaceFloorDivide15213359
Ref: 4d3215213359
Ref: c-api/number c PyNumber_InPlaceTrueDivide15213765
Ref: 4d3a15213765
Ref: c-api/number c PyNumber_InPlaceRemainder15214449
Ref: 4d3715214449
Ref: c-api/number c PyNumber_InPlacePower15214837
Ref: 4d3615214837
Ref: c-api/number c PyNumber_InPlaceLshift15215475
Ref: 4d3315215475
Ref: c-api/number c PyNumber_InPlaceRshift15215880
Ref: 4d3815215880
Ref: c-api/number c PyNumber_InPlaceAnd15216286
Ref: 4d3115216286
Ref: c-api/number c PyNumber_InPlaceXor15216685
Ref: 4d3b15216685
Ref: c-api/number c PyNumber_InPlaceOr15217092
Ref: 4d3515217092
Ref: c-api/number c PyNumber_Long15217489
Ref: a7615217489
Ref: c-api/number c PyNumber_Float15217799
Ref: a7715217799
Ref: c-api/number c PyNumber_Index15218109
Ref: 89a15218109
Ref: c-api/number c PyNumber_ToBase15218557
Ref: 191915218557
Ref: c-api/number c PyNumber_AsSsize_t15219082
Ref: 4d2d15219082
Ref: c-api/number c PyIndex_Check15219885
Ref: 99415219885
Node: Sequence Protocol15220187
Ref: c-api/sequence doc15220312
Ref: 4f5415220312
Ref: c-api/sequence sequence15220312
Ref: 4f5515220312
Ref: c-api/sequence sequence-protocol15220312
Ref: 4f5615220312
Ref: c-api/sequence translation-repo15220312
Ref: 4f5715220312
Ref: c-api/sequence c PySequence_Check15220361
Ref: 4d6615220361
Ref: c-api/sequence c PySequence_Size15220818
Ref: 1be415220818
Ref: c-api/sequence c PySequence_Length15220887
Ref: 4d7015220887
Ref: c-api/sequence c PySequence_Concat15221155
Ref: 4d6715221155
Ref: c-api/sequence c PySequence_Repeat15221486
Ref: 4d7215221486
Ref: c-api/sequence c PySequence_InPlaceConcat15221833
Ref: 4d6d15221833
Ref: c-api/sequence c PySequence_InPlaceRepeat15222234
Ref: 4d6e15222234
Ref: c-api/sequence c PySequence_GetItem15222650
Ref: 1be515222650
Ref: c-api/sequence c PySequence_GetSlice15222951
Ref: 4d6c15222951
Ref: c-api/sequence c PySequence_SetItem15223308
Ref: 1be615223308
Ref: c-api/sequence c PySequence_DelItem15223846
Ref: 1be715223846
Ref: c-api/sequence c PySequence_SetSlice15224102
Ref: 4d7315224102
Ref: c-api/sequence c PySequence_DelSlice15224418
Ref: 4d6a15224418
Ref: c-api/sequence c PySequence_Count15224724
Ref: 4d6915224724
Ref: c-api/sequence c PySequence_Contains15225098
Ref: 4d6815225098
Ref: c-api/sequence c PySequence_Index15225437
Ref: 4d6f15225437
Ref: c-api/sequence c PySequence_List15225742
Ref: 4d7115225742
Ref: c-api/sequence c PySequence_Tuple15226113
Ref: 4d7415226113
Ref: c-api/sequence c PySequence_Fast15226576
Ref: 4d6b15226576
Ref: c-api/sequence c PySequence_Fast_GET_SIZE15227320
Ref: 4f5915227320
Ref: c-api/sequence c PySequence_Fast_GET_ITEM15227741
Ref: 4f5a15227741
Ref: c-api/sequence c PySequence_Fast_ITEMS15228047
Ref: 4f5b15228047
Ref: c-api/sequence c PySequence_ITEM15228473
Ref: 4f5c15228473
Node: Mapping Protocol15228844
Ref: c-api/mapping doc15228971
Ref: 4f5d15228971
Ref: c-api/mapping mapping15228971
Ref: 4f5e15228971
Ref: c-api/mapping mapping-protocol15228971
Ref: 4f5f15228971
Ref: c-api/mapping translation-repo15228971
Ref: 4f6015228971
Ref: c-api/mapping c PyMapping_Check15229127
Ref: 4d1615229127
Ref: c-api/mapping c PyMapping_Size15229557
Ref: 1be815229557
Ref: c-api/mapping c PyMapping_Length15229625
Ref: 4d1715229625
Ref: c-api/mapping c PyMapping_GetItemString15229887
Ref: 34915229887
Ref: c-api/mapping c PyMapping_GetOptionalItem15230237
Ref: 34615230237
Ref: c-api/mapping c PyMapping_GetOptionalItemString15230914
Ref: 34715230914
Ref: c-api/mapping c PyMapping_SetItemString15231302
Ref: 4d1815231302
Ref: c-api/mapping c PyMapping_DelItem15231612
Ref: 4f6115231612
Ref: c-api/mapping c PyMapping_DelItemString15231738
Ref: 4f6215231738
Ref: c-api/mapping c PyMapping_HasKeyWithError15231997
Ref: 38115231997
Ref: c-api/mapping c PyMapping_HasKeyStringWithError15232359
Ref: 38315232359
Ref: c-api/mapping c PyMapping_HasKey15232726
Ref: 38215232726
Ref: c-api/mapping c PyMapping_HasKeyString15233328
Ref: 38415233328
Ref: c-api/mapping c PyMapping_Keys15234016
Ref: c-api/mapping c PyMapping_Values15234342
Ref: bdc15234342
Ref: c-api/mapping c PyMapping_Items15234672
Ref: bdd15234672
Node: Iterator Protocol15235061
Ref: c-api/iter doc15235186
Ref: 4f6315235186
Ref: c-api/iter iterator15235186
Ref: 4f6415235186
Ref: c-api/iter iterator-protocol15235186
Ref: 4f6515235186
Ref: c-api/iter translation-repo15235186
Ref: 4f6615235186
Ref: c-api/iter c PyIter_Check15235301
Ref: 1a5815235301
Ref: c-api/iter c PyAIter_Check15235567
Ref: 4c2515235567
Ref: c-api/iter c PyIter_Next15235851
Ref: 4cff15235851
Ref: c-api/iter c PySendResult15236912
Ref: 4f6715236912
Ref: c-api/iter c PyIter_Send15237063
Ref: 89f15237063
Node: Buffer Protocol15237648
Ref: c-api/buffer doc15237748
Ref: 4f6815237748
Ref: c-api/buffer buffer-protocol15237748
Ref: 4f6915237748
Ref: c-api/buffer bufferobjects15237748
Ref: 2e815237748
Ref: c-api/buffer translation-repo15237748
Ref: 4f6a15237748
Node: Buffer structure15240515
Ref: c-api/buffer buffer-structure15240612
Ref: 4f6c15240612
Ref: c-api/buffer id115240612
Ref: 4f6d15240612
Ref: c-api/buffer c Py_buffer15241687
Ref: 75b15241687
Ref: c-api/buffer c Py_buffer buf15241805
Ref: 4f6f15241805
Ref: c-api/buffer c Py_buffer obj15242267
Ref: 4f7115242267
Ref: c-api/buffer c Py_buffer len15242904
Ref: 4f7215242904
Ref: c-api/buffer c Py_buffer readonly15243516
Ref: 4f7315243516
Ref: c-api/buffer c Py_buffer itemsize15243686
Ref: 4f7415243686
Ref: c-api/buffer c Py_buffer format15244615
Ref: 4f7515244615
Ref: c-api/buffer c Py_buffer ndim15244937
Ref: 4f7715244937
Ref: c-api/buffer c Py_buffer shape15245361
Ref: 4f7615245361
Ref: c-api/buffer c Py_buffer strides15245926
Ref: 4f7015245926
Ref: c-api/buffer c Py_buffer suboffsets15246464
Ref: 4f7815246464
Ref: c-api/buffer c Py_buffer internal15247368
Ref: 4f7a15247368
Ref: c-api/buffer c PyBUF_MAX_NDIM15247755
Ref: 4c2f15247755
Node: Buffer request types15248085
Ref: c-api/buffer buffer-request-types15248205
Ref: 472615248205
Ref: c-api/buffer id215248205
Ref: 4f7b15248205
Node: request-independent fields15248813
Ref: c-api/buffer request-independent-fields15248920
Ref: 4f7c15248920
Node: readonly format15249188
Ref: c-api/buffer readonly-format15249328
Ref: 4f7d15249328
Ref: c-api/buffer c PyBUF_WRITABLE15249379
Ref: 140215249379
Ref: c-api/buffer c PyBUF_WRITEABLE15249918
Ref: 4f7e15249918
Ref: c-api/buffer c PyBUF_FORMAT15250049
Ref: 4c2b15250049
Node: shape strides suboffsets15250745
Ref: c-api/buffer shape-strides-suboffsets15250878
Ref: 4f7f15250878
Ref: c-api/buffer c PyBUF_INDIRECT15251415
Ref: 4c2e15251415
Ref: c-api/buffer c PyBUF_STRIDES15251600
Ref: 4c3615251600
Ref: c-api/buffer c PyBUF_ND15251776
Ref: 4c3015251776
Ref: c-api/buffer c PyBUF_SIMPLE15251961
Ref: 4c3315251961
Node: contiguity requests15252117
Ref: c-api/buffer contiguity-requests15252252
Ref: 4f8015252252
Ref: c-api/buffer c PyBUF_C_CONTIGUOUS15252861
Ref: 140315252861
Ref: c-api/buffer c PyBUF_F_CONTIGUOUS15253085
Ref: 140415253085
Ref: c-api/buffer c PyBUF_ANY_CONTIGUOUS15253311
Ref: 4c2815253311
Node: compound requests15253677
Ref: c-api/buffer compound-requests15253779
Ref: 4f8115253779
Ref: c-api/buffer c PyBUF_FULL15254653
Ref: 4c2c15254653
Ref: c-api/buffer c PyBUF_FULL_RO15254930
Ref: 4c2d15254930
Ref: c-api/buffer c PyBUF_RECORDS15255204
Ref: 4c3115255204
Ref: c-api/buffer c PyBUF_RECORDS_RO15255481
Ref: 4c3215255481
Ref: c-api/buffer c PyBUF_STRIDED15255752
Ref: 4c3415255752
Ref: c-api/buffer c PyBUF_STRIDED_RO15256030
Ref: 4c3515256030
Ref: c-api/buffer c PyBUF_CONTIG15256301
Ref: 4c2915256301
Ref: c-api/buffer c PyBUF_CONTIG_RO15256579
Ref: 4c2a15256579
Node: Complex arrays15256826
Ref: c-api/buffer complex-arrays15256954
Ref: 4f7915256954
Node: NumPy-style shape and strides15257160
Ref: c-api/buffer numpy-style-shape-and-strides15257287
Ref: 4f8215257287
Node: PIL-style shape strides and suboffsets15259167
Ref: c-api/buffer pil-style-shape-strides-and-suboffsets15259294
Ref: 4f8315259294
Node: Buffer-related functions15260520
Ref: c-api/buffer buffer-related-functions15260619
Ref: 4f8415260619
Ref: c-api/buffer c PyObject_CheckBuffer15260688
Ref: 39b15260688
Ref: c-api/buffer c PyObject_GetBuffer15261032
Ref: 39c15261032
Ref: c-api/buffer c PyBuffer_Release15262036
Ref: 39d15262036
Ref: c-api/buffer c PyBuffer_SizeFromFormat15262565
Ref: 75d15262565
Ref: c-api/buffer c PyBuffer_IsContiguous15262873
Ref: 76115262873
Ref: c-api/buffer c PyBuffer_GetPointer15263292
Ref: 75c15263292
Ref: c-api/buffer c PyBuffer_FromContiguous15263605
Ref: 75f15263605
Ref: c-api/buffer c PyBuffer_ToContiguous15263988
Ref: 75e15263988
Ref: c-api/buffer c PyObject_CopyData15264466
Ref: 76015264466
Ref: c-api/buffer c PyBuffer_FillContiguousStrides15264766
Ref: 76215264766
Ref: c-api/buffer c PyBuffer_FillInfo15265217
Ref: 76315265217
Node: Concrete Objects Layer15266247
Ref: c-api/concrete doc15266414
Ref: 4f8515266414
Ref: c-api/concrete concrete15266414
Ref: 4f8615266414
Ref: c-api/concrete concrete-objects-layer15266414
Ref: 4f8715266414
Ref: c-api/concrete translation-repo15266414
Ref: 4f8815266414
Node: Fundamental Objects15267431
Ref: c-api/concrete fundamental15267533
Ref: 4f8a15267533
Ref: c-api/concrete fundamental-objects15267533
Ref: 4f8b15267533
Node: Type Objects<2>15267730
Ref: c-api/type doc15267825
Ref: 4f8c15267825
Ref: c-api/type type-objects15267825
Ref: 4f8d15267825
Ref: c-api/type typeobjects15267825
Ref: 4f8e15267825
Ref: c-api/type c PyTypeObject15267868
Ref: aba15267868
Ref: c-api/type c PyType_Type15268036
Ref: 55015268036
Ref: c-api/type c PyType_Check15268249
Ref: 1b3015268249
Ref: c-api/type c PyType_CheckExact15268495
Ref: 1b3115268495
Ref: c-api/type c PyType_ClearCache15268724
Ref: 4da215268724
Ref: c-api/type c PyType_GetFlags15268890
Ref: 1ae415268890
Ref: c-api/type c PyType_GetDict15269428
Ref: 182a15269428
Ref: c-api/type c PyType_Modified15270171
Ref: 192115270171
Ref: c-api/type c PyType_AddWatcher15270471
Ref: 56715270471
Ref: c-api/type c PyType_ClearWatcher15270989
Ref: 4f8f15270989
Ref: c-api/type c PyType_Watch15271460
Ref: 56815271460
Ref: c-api/type c PyType_Unwatch15272163
Ref: 4f9015272163
Ref: c-api/type c PyType_WatchCallback15272675
Ref: 4f9115272675
Ref: c-api/type c PyType_HasFeature15273030
Ref: 1ae315273030
Ref: c-api/type c PyType_FastSubclass15273225
Ref: 4f9215273225
Ref: c-api/type c PyType_IS_GC15273721
Ref: 4f9415273721
Ref: c-api/type c PyType_IsSubtype15273912
Ref: 4da315273912
Ref: c-api/type c PyType_GenericAlloc15274315
Ref: a7a15274315
Ref: c-api/type c PyType_GenericNew15274709
Ref: 4b9715274709
Ref: c-api/type c PyType_Ready15275055
Ref: 77f15275055
Ref: c-api/type c PyType_GetName15275943
Ref: 75515275943
Ref: c-api/type c PyType_GetQualName15276257
Ref: 75615276257
Ref: c-api/type c PyType_GetFullyQualifiedName15276589
Ref: 37615276589
Ref: c-api/type c PyType_GetModuleName15277020
Ref: 37815277020
Ref: c-api/type c PyType_GetSlot15277313
Ref: 8a315277313
Ref: c-api/type c PyType_GetModule15278013
Ref: 97815278013
Ref: c-api/type c PyType_GetModuleState15279203
Ref: 97915279203
Ref: c-api/type c PyType_GetModuleByDef15279795
Ref: 39715279795
Ref: c-api/type c PyUnstable_Type_AssignVersionTag15280783
Ref: 4f9715280783
Ref: c-api/type c PyType_SUPPORTS_WEAKREFS15281254
Ref: 4f9815281254
Node: Creating Heap-Allocated Types15281637
Ref: c-api/type creating-heap-allocated-types15281718
Ref: 4f9a15281718
Ref: c-api/type c PyType_FromMetaclass15281874
Ref: 55315281874
Ref: c-api/type c PyType_FromModuleAndSpec15284291
Ref: 55415284291
Ref: c-api/type c PyType_FromSpecWithBases15285196
Ref: 58115285196
Ref: c-api/type c PyType_FromSpec15285939
Ref: 58015285939
Ref: c-api/type c PyType_Spec15286638
Ref: 182815286638
Ref: c-api/type c PyType_Spec name15286781
Ref: 4f9b15286781
Ref: c-api/type c PyType_Spec basicsize15286903
Ref: 54b15286903
Ref: c-api/type c PyType_Spec itemsize15287669
Ref: 4f9c15287669
Ref: c-api/type c PyType_Spec flags15288792
Ref: 4f9d15288792
Ref: c-api/type c PyType_Spec slots15289034
Ref: 4f9e15289034
Ref: c-api/type c PyType_Slot15289266
Ref: 4da415289266
Ref: c-api/type c PyType_Slot slot15289469
Ref: 4f9515289469
Ref: c-api/type c PyType_Slot pfunc15291735
Ref: 4fa815291735
Node: The None Object15291935
Ref: c-api/none doc15292030
Ref: 4fa915292030
Ref: c-api/none noneobject15292030
Ref: 4faa15292030
Ref: c-api/none the-none-object15292030
Ref: 4fab15292030
Ref: c-api/none translation-repo15292030
Ref: 4fac15292030
Ref: c-api/none c Py_None15292349
Ref: 4b6915292349
Ref: c-api/none c Py_RETURN_NONE15292600
Ref: 14c215292600
Node: Numeric Objects15292680
Ref: c-api/concrete numeric-objects15292807
Ref: 4fad15292807
Ref: c-api/concrete numericobjects15292807
Ref: 4fae15292807
Node: Integer Objects15292956
Ref: c-api/long doc15293047
Ref: 4faf15293047
Ref: c-api/long integer-objects15293047
Ref: 4fb015293047
Ref: c-api/long longobjects15293047
Ref: 4fb115293047
Ref: c-api/long c PyLongObject15293339
Ref: 58b15293339
Ref: c-api/long c PyLong_Type15293516
Ref: 4d1415293516
Ref: c-api/long c PyLong_Check15293767
Ref: 4fb215293767
Ref: c-api/long c PyLong_CheckExact15293952
Ref: 4fb315293952
Ref: c-api/long c PyLong_FromLong15294147
Ref: 197515294147
Ref: c-api/long c PyLong_FromUnsignedLong15294623
Ref: 1b5115294623
Ref: c-api/long c PyLong_FromSsize_t15294894
Ref: 4d1015294894
Ref: c-api/long c PyLong_FromSize_t15295155
Ref: 1b5315295155
Ref: c-api/long c PyLong_FromLongLong15295402
Ref: 197615295402
Ref: c-api/long c PyLong_FromUnsignedLongLong15295651
Ref: 1b5215295651
Ref: c-api/long c PyLong_FromDouble15295936
Ref: 94c15295936
Ref: c-api/long c PyLong_FromString15296190
Ref: 4d1115296190
Ref: c-api/long c PyLong_FromUnicodeObject15297524
Ref: 8c215297524
Ref: c-api/long c PyLong_FromVoidPtr15297774
Ref: 4d1215297774
Ref: c-api/long c PyLong_FromNativeBytes15298077
Ref: 36515298077
Ref: c-api/long c PyLong_FromUnsignedNativeBytes15298757
Ref: 36615298757
Ref: c-api/long c PyLong_FromPid15299297
Ref: 4fb415299297
Ref: c-api/long c PyLong_AsLong15299599
Ref: 36315299599
Ref: c-api/long c PyLong_AS_LONG15300257
Ref: 4fb515300257
Ref: c-api/long c PyLong_AsInt15300607
Ref: 36215300607
Ref: c-api/long c PyLong_AsLongAndOverflow15300852
Ref: 12ad15300852
Ref: c-api/long c PyLong_AsLongLong15301753
Ref: 4d0a15301753
Ref: c-api/long c PyLong_AsLongLongAndOverflow15302430
Ref: 12ac15302430
Ref: c-api/long c PyLong_AsSsize_t15303375
Ref: 4d0c15303375
Ref: c-api/long c PyLong_AsUnsignedLong15303837
Ref: 4d0d15303837
Ref: c-api/long c PyLong_AsSize_t15304284
Ref: 4d0b15304284
Ref: c-api/long c PyLong_AsUnsignedLongLong15304709
Ref: 12db15304709
Ref: c-api/long c PyLong_AsUnsignedLongMask15305309
Ref: 4d0e15305309
Ref: c-api/long c PyLong_AsUnsignedLongLongMask15306048
Ref: 1b7615306048
Ref: c-api/long c PyLong_AsDouble15306822
Ref: 4d0915306822
Ref: c-api/long c PyLong_AsVoidPtr15307229
Ref: 4d0f15307229
Ref: c-api/long c PyLong_AsPid15307691
Ref: 176315307691
Ref: c-api/long c PyLong_AsNativeBytes15308017
Ref: 36415308017
Ref: c-api/long c Py_ASNATIVEBYTES_DEFAULTS15312168
Ref: 4fb615312168
Ref: c-api/long c Py_ASNATIVEBYTES_BIG_ENDIAN15312346
Ref: 4fb715312346
Ref: c-api/long c Py_ASNATIVEBYTES_LITTLE_ENDIAN15312524
Ref: 4fb815312524
Ref: c-api/long c Py_ASNATIVEBYTES_NATIVE_ENDIAN15312699
Ref: 4fb915312699
Ref: c-api/long c Py_ASNATIVEBYTES_UNSIGNED_BUFFER15312876
Ref: 4fba15312876
Ref: c-api/long c Py_ASNATIVEBYTES_REJECT_NEGATIVE15313051
Ref: 4fbb15313051
Ref: c-api/long c Py_ASNATIVEBYTES_ALLOW_INDEX15313222
Ref: 4fbc15313222
Ref: c-api/long c PyLong_GetInfo15315166
Ref: 4d1315315166
Ref: c-api/long c PyUnstable_Long_IsCompact15315574
Ref: 58c15315574
Ref: c-api/long c PyUnstable_Long_CompactValue15316365
Ref: 58d15316365
Node: Boolean Objects15316819
Ref: c-api/bool doc15316941
Ref: 4fbd15316941
Ref: c-api/bool boolean-objects15316941
Ref: 4fbe15316941
Ref: c-api/bool boolobjects15316941
Ref: 4fbf15316941
Ref: c-api/bool translation-repo15316941
Ref: 4fc015316941
Ref: c-api/bool c PyBool_Type15317256
Ref: 4c3915317256
Ref: c-api/bool c PyBool_Check15317505
Ref: 4fc315317505
Ref: c-api/bool c Py_False15317651
Ref: 4fc115317651
Ref: c-api/bool c Py_True15317881
Ref: 4fc215317881
Ref: c-api/bool c Py_RETURN_FALSE15318108
Ref: 14c415318108
Ref: c-api/bool c Py_RETURN_TRUE15318190
Ref: 14c315318190
Ref: c-api/bool c PyBool_FromLong15318270
Ref: 4c3815318270
Node: Floating-Point Objects15318509
Ref: c-api/float doc15318638
Ref: 4fc415318638
Ref: c-api/float floating-point-objects15318638
Ref: 4fc515318638
Ref: c-api/float floatobjects15318638
Ref: 4fc615318638
Ref: c-api/float translation-repo15318638
Ref: 4fc715318638
Ref: c-api/float c PyFloatObject15318701
Ref: 4fc815318701
Ref: c-api/float c PyFloat_Type15318824
Ref: 4ced15318824
Ref: c-api/float c PyFloat_Check15319085
Ref: 4fc915319085
Ref: c-api/float c PyFloat_CheckExact15319274
Ref: 4fca15319274
Ref: c-api/float c PyFloat_FromString15319473
Ref: 4cec15319473
Ref: c-api/float c PyFloat_FromDouble15319737
Ref: 4ceb15319737
Ref: c-api/float c PyFloat_AsDouble15319970
Ref: a7815319970
Ref: c-api/float c PyFloat_AS_DOUBLE15320606
Ref: 4fcb15320606
Ref: c-api/float c PyFloat_GetInfo15320770
Ref: 143e15320770
Ref: c-api/float c PyFloat_GetMax15321098
Ref: 143c15321098
Ref: c-api/float c PyFloat_GetMin15321258
Ref: 143d15321258
Ref: c-api/float c Py_INFINITY15321417
Ref: 4fcc15321417
Ref: c-api/float c Py_NAN15321675
Ref: 4fcd15321675
Ref: c-api/float c Py_HUGE_VAL15321935
Ref: 4fce15321935
Ref: c-api/float c Py_MATH_E15322080
Ref: 4fcf15322080
Ref: c-api/float c Py_MATH_El15322196
Ref: 4fd015322196
Ref: c-api/float c Py_MATH_PI15322295
Ref: 4fd115322295
Ref: c-api/float c Py_MATH_PIl15322413
Ref: 4fd215322413
Ref: c-api/float c Py_MATH_TAU15322519
Ref: 4fd315322519
Ref: c-api/float c Py_RETURN_NAN15322667
Ref: 4fd415322667
Ref: c-api/float c Py_RETURN_INF15322836
Ref: 4fd515322836
Ref: c-api/float c Py_IS_FINITE15323105
Ref: 4fd615323105
Ref: c-api/float c Py_IS_INFINITY15323422
Ref: 4fd715323422
Ref: c-api/float c Py_IS_NAN15323690
Ref: 14c515323690
Node: Pack and Unpack functions15323990
Ref: c-api/float pack-and-unpack-functions15324074
Ref: 4fd815324074
Node: Pack functions15325375
Ref: c-api/float pack-functions15325476
Ref: 4fd915325476
Ref: c-api/float c PyFloat_Pack215326250
Ref: 76815326250
Ref: c-api/float c PyFloat_Pack415326383
Ref: 76915326383
Ref: c-api/float c PyFloat_Pack815326518
Ref: 76a15326518
Node: Unpack functions15326653
Ref: c-api/float unpack-functions15326754
Ref: 4fda15326754
Ref: c-api/float c PyFloat_Unpack215327505
Ref: 76b15327505
Ref: c-api/float c PyFloat_Unpack415327641
Ref: 76c15327641
Ref: c-api/float c PyFloat_Unpack815327779
Ref: 76d15327779
Node: Complex Number Objects15327917
Ref: c-api/complex doc15328022
Ref: 4fdb15328022
Ref: c-api/complex complex-number-objects15328022
Ref: 4fdc15328022
Ref: c-api/complex complexobjects15328022
Ref: 4fdd15328022
Ref: c-api/complex translation-repo15328022
Ref: 4fde15328022
Node: Complex Numbers as C Structures15328455
Ref: c-api/complex complex-numbers-as-c-structures15328587
Ref: 4fdf15328587
Ref: c-api/complex c Py_complex15328870
Ref: 4eee15328870
Ref: c-api/complex c Py_complex real15329144
Ref: 4fe015329144
Ref: c-api/complex c Py_complex imag15329175
Ref: 4fe115329175
Ref: c-api/complex c _Py_c_sum15329348
Ref: 4fe215329348
Ref: c-api/complex c _Py_c_diff15329547
Ref: 4fe315329547
Ref: c-api/complex c _Py_c_neg15329759
Ref: 4fe415329759
Ref: c-api/complex c _Py_c_prod15329939
Ref: 4fe515329939
Ref: c-api/complex c _Py_c_quot15330143
Ref: 4fe615330143
Ref: c-api/complex c _Py_c_pow15330448
Ref: 16b915330448
Node: Complex Numbers as Python Objects15330780
Ref: c-api/complex complex-numbers-as-python-objects15330912
Ref: 4fe715330912
Ref: c-api/complex c PyComplexObject15330997
Ref: 4fe815330997
Ref: c-api/complex c PyComplex_Type15331122
Ref: 4c7015331122
Ref: c-api/complex c PyComplex_Check15331385
Ref: 4fe915331385
Ref: c-api/complex c PyComplex_CheckExact15331580
Ref: 4fea15331580
Ref: c-api/complex c PyComplex_FromCComplex15331785
Ref: 4feb15331785
Ref: c-api/complex c PyComplex_FromDoubles15332052
Ref: 4c6f15332052
Ref: c-api/complex c PyComplex_RealAsDouble15332359
Ref: 17aa15332359
Ref: c-api/complex c PyComplex_ImagAsDouble15333064
Ref: 17ab15333064
Ref: c-api/complex c PyComplex_AsCComplex15333784
Ref: 143f15333784
Node: Sequence Objects15334608
Ref: c-api/concrete sequence-objects15334733
Ref: 4fec15334733
Ref: c-api/concrete sequenceobjects15334733
Ref: 4fed15334733
Node: Bytes Objects<2>15335128
Ref: c-api/bytes doc15335224
Ref: 4fee15335224
Ref: c-api/bytes bytes-objects15335224
Ref: 4fef15335224
Ref: c-api/bytes bytesobjects15335224
Ref: 4ff015335224
Ref: c-api/bytes c PyBytesObject15335386
Ref: 79515335386
Ref: c-api/bytes c PyBytes_Type15335500
Ref: 4c4a15335500
Ref: c-api/bytes c PyBytes_Check15335749
Ref: 13ec15335749
Ref: c-api/bytes c PyBytes_CheckExact15335936
Ref: 4ff115335936
Ref: c-api/bytes c PyBytes_FromString15336139
Ref: 4c4715336139
Ref: c-api/bytes c PyBytes_FromStringAndSize15336474
Ref: 13ed15336474
Ref: c-api/bytes c PyBytes_FromFormat15336867
Ref: 1bba15336867
Ref: c-api/bytes c PyBytes_FromFormatV15340779
Ref: 4c4515340779
Ref: c-api/bytes c PyBytes_FromObject15341060
Ref: 4c4615341060
Ref: c-api/bytes c PyBytes_Size15341300
Ref: 4c4915341300
Ref: c-api/bytes c PyBytes_GET_SIZE15341468
Ref: 4ff215341468
Ref: c-api/bytes c PyBytes_AsString15341612
Ref: 88e15341612
Ref: c-api/bytes c PyBytes_AS_STRING15342262
Ref: 4ff315342262
Ref: c-api/bytes c PyBytes_AsStringAndSize15342403
Ref: 4c4115342403
Ref: c-api/bytes c PyBytes_Concat15343477
Ref: 4c4215343477
Ref: c-api/bytes c PyBytes_ConcatAndDel15344013
Ref: 4c4315344013
Ref: c-api/bytes c _PyBytes_Resize15344367
Ref: 176215344367
Ref: c-api/bytes c PyBytes_Repr15345098
Ref: 4c4815345098
Ref: c-api/bytes c PyBytes_DecodeEscape15346035
Ref: 4c4415346035
Ref: Bytes Objects<2>-Footnote-115346865
Ref: Bytes Objects<2>-Footnote-215346991
Ref: Bytes Objects<2>-Footnote-315347117
Ref: Bytes Objects<2>-Footnote-415347243
Ref: Bytes Objects<2>-Footnote-515347369
Ref: Bytes Objects<2>-Footnote-615347495
Ref: Bytes Objects<2>-Footnote-715347621
Ref: Bytes Objects<2>-Footnote-815347747
Node: Byte Array Objects15347873
Ref: c-api/bytearray doc15348004
Ref: 4ff415348004
Ref: c-api/bytearray byte-array-objects15348004
Ref: 4ff515348004
Ref: c-api/bytearray bytearrayobjects15348004
Ref: 4ff615348004
Ref: c-api/bytearray translation-repo15348004
Ref: 4ff715348004
Ref: c-api/bytearray c PyByteArrayObject15348059
Ref: 4ff815348059
Ref: c-api/bytearray c PyByteArray_Type15348181
Ref: 4c3f15348181
Node: Type check macros15348510
Ref: c-api/bytearray type-check-macros15348611
Ref: 4ff915348611
Ref: c-api/bytearray c PyByteArray_Check15348664
Ref: 4ffa15348664
Ref: c-api/bytearray c PyByteArray_CheckExact15348863
Ref: 4ffb15348863
Node: Direct API functions15349078
Ref: c-api/bytearray direct-api-functions15349194
Ref: 4ffc15349194
Ref: c-api/bytearray c PyByteArray_FromObject15349253
Ref: 13f515349253
Ref: c-api/bytearray c PyByteArray_FromStringAndSize15349583
Ref: 13f615349583
Ref: c-api/bytearray c PyByteArray_Concat15349910
Ref: 4c3c15349910
Ref: c-api/bytearray c PyByteArray_Size15350223
Ref: 4c3e15350223
Ref: c-api/bytearray c PyByteArray_AsString15350433
Ref: 4c3b15350433
Ref: c-api/bytearray c PyByteArray_Resize15350704
Ref: 4c3d15350704
Node: Macros15350893
Ref: c-api/bytearray macros15350983
Ref: 4ffd15350983
Ref: c-api/bytearray c PyByteArray_AS_STRING15351084
Ref: 4ffe15351084
Ref: c-api/bytearray c PyByteArray_GET_SIZE15351237
Ref: 4fff15351237
Node: Unicode Objects and Codecs15351412
Ref: c-api/unicode doc15351540
Ref: 11e415351540
Ref: c-api/unicode translation-repo15351540
Ref: 500015351540
Ref: c-api/unicode unicode-objects-and-codecs15351540
Ref: 500115351540
Ref: c-api/unicode unicodeobjects15351540
Ref: 500215351540
Node: Unicode Objects15351692
Ref: c-api/unicode unicode-objects15351794
Ref: 500315351794
Ref: Unicode Objects-Footnote-115352667
Ref: Unicode Objects-Footnote-215352709
Node: Unicode Type15352751
Ref: c-api/unicode unicode-type15352852
Ref: 500415352852
Ref: c-api/unicode c Py_UCS415352984
Ref: 29b15352984
Ref: c-api/unicode c Py_UCS215353009
Ref: 11b815353009
Ref: c-api/unicode c Py_UCS115353034
Ref: 11b715353034
Ref: c-api/unicode c Py_UNICODE15353349
Ref: 3f015353349
Ref: c-api/unicode c PyASCIIObject15353766
Ref: 11b915353766
Ref: c-api/unicode c PyCompactUnicodeObject15353797
Ref: 11ba15353797
Ref: c-api/unicode c PyUnicodeObject15353837
Ref: 79715353837
Ref: c-api/unicode c PyUnicode_Type15354147
Ref: 4de215354147
Ref: c-api/unicode c PyUnicodeIter_Type15354380
Ref: 4db615354380
Ref: c-api/unicode c PyUnicode_Check15354770
Ref: 500515354770
Ref: c-api/unicode c PyUnicode_CheckExact15354955
Ref: 500615354955
Ref: c-api/unicode c PyUnicode_READY15355143
Ref: 40415355143
Ref: c-api/unicode c PyUnicode_GET_LENGTH15355385
Ref: 8bc15355385
Ref: c-api/unicode c PyUnicode_1BYTE_DATA15355668
Ref: 11be15355668
Ref: c-api/unicode c PyUnicode_2BYTE_DATA15355757
Ref: 11bf15355757
Ref: c-api/unicode c PyUnicode_4BYTE_DATA15355846
Ref: 11c015355846
Ref: c-api/unicode c PyUnicode_1BYTE_KIND15356261
Ref: 11c215356261
Ref: c-api/unicode c PyUnicode_2BYTE_KIND15356295
Ref: 11c315356295
Ref: c-api/unicode c PyUnicode_4BYTE_KIND15356329
Ref: 11c415356329
Ref: c-api/unicode c PyUnicode_KIND15356532
Ref: 11c115356532
Ref: c-api/unicode c PyUnicode_DATA15356870
Ref: 11bd15356870
Ref: c-api/unicode c PyUnicode_WRITE15357112
Ref: 11c715357112
Ref: c-api/unicode c PyUnicode_READ15357676
Ref: 11c515357676
Ref: c-api/unicode c PyUnicode_READ_CHAR15357971
Ref: 11c615357971
Ref: c-api/unicode c PyUnicode_MAX_CHAR_VALUE15358320
Ref: 11c815358320
Ref: c-api/unicode c PyUnicode_IsIdentifier15358693
Ref: 1b2f15358693
Node: Unicode Character Properties15359099
Ref: c-api/unicode unicode-character-properties15359247
Ref: 500715359247
Ref: c-api/unicode c Py_UNICODE_ISSPACE15359511
Ref: 1a6b15359511
Ref: c-api/unicode c Py_UNICODE_ISLOWER15359654
Ref: 500815359654
Ref: c-api/unicode c Py_UNICODE_ISUPPER15359796
Ref: 500915359796
Ref: c-api/unicode c Py_UNICODE_ISTITLE15359939
Ref: 500a15359939
Ref: c-api/unicode c Py_UNICODE_ISLINEBREAK15360081
Ref: 500b15360081
Ref: c-api/unicode c Py_UNICODE_ISDECIMAL15360227
Ref: 500c15360227
Ref: c-api/unicode c Py_UNICODE_ISDIGIT15360364
Ref: 500d15360364
Ref: c-api/unicode c Py_UNICODE_ISNUMERIC15360497
Ref: 500e15360497
Ref: c-api/unicode c Py_UNICODE_ISALPHA15360634
Ref: 500f15360634
Ref: c-api/unicode c Py_UNICODE_ISALNUM15360778
Ref: 501015360778
Ref: c-api/unicode c Py_UNICODE_ISPRINTABLE15360924
Ref: 501115360924
Ref: c-api/unicode c Py_UNICODE_TOLOWER15361179
Ref: 501215361179
Ref: c-api/unicode c Py_UNICODE_TOUPPER15361305
Ref: 501315361305
Ref: c-api/unicode c Py_UNICODE_TOTITLE15361431
Ref: 501415361431
Ref: c-api/unicode c Py_UNICODE_TODECIMAL15361557
Ref: 501515361557
Ref: c-api/unicode c Py_UNICODE_TODIGIT15361778
Ref: 501615361778
Ref: c-api/unicode c Py_UNICODE_TONUMERIC15361993
Ref: 501715361993
Ref: c-api/unicode c Py_UNICODE_IS_SURROGATE15362246
Ref: 501815362246
Ref: c-api/unicode c Py_UNICODE_IS_HIGH_SURROGATE15362371
Ref: 501915362371
Ref: c-api/unicode c Py_UNICODE_IS_LOW_SURROGATE15362506
Ref: 501a15362506
Ref: c-api/unicode c Py_UNICODE_HIGH_SURROGATE15362639
Ref: 501b15362639
Ref: c-api/unicode c Py_UNICODE_LOW_SURROGATE15362865
Ref: 501c15362865
Ref: c-api/unicode c Py_UNICODE_JOIN_SURROGATES15363089
Ref: 501d15363089
Node: Creating and accessing Unicode strings15363494
Ref: c-api/unicode creating-and-accessing-unicode-strings15363645
Ref: 501e15363645
Ref: c-api/unicode c PyUnicode_New15363829
Ref: 8b315363829
Ref: c-api/unicode c PyUnicode_FromKindAndData15364402
Ref: 11bb15364402
Ref: c-api/unicode c PyUnicode_FromStringAndSize15365204
Ref: 4ddb15365204
Ref: c-api/unicode c PyUnicode_FromString15365874
Ref: 4dda15365874
Ref: c-api/unicode c PyUnicode_FromFormat15366127
Ref: 38d15366127
Ref: c-api/unicode c PyUnicode_FromFormatV15379080
Ref: 57715379080
Ref: c-api/unicode c PyUnicode_FromObject15379364
Ref: 4dd815379364
Ref: c-api/unicode c PyUnicode_FromOrdinal15379832
Ref: 4dd915379832
Ref: c-api/unicode c PyUnicode_FromEncodedObject15380187
Ref: 4dd715380187
Ref: c-api/unicode c PyUnicode_BuildEncodingMap15380999
Ref: 180115380999
Ref: c-api/unicode c PyUnicode_GetDefaultEncoding15381562
Ref: 4ddc15381562
Ref: c-api/unicode c PyUnicode_GetLength15381886
Ref: 8bb15381886
Ref: c-api/unicode c PyUnicode_CopyCharacters15382183
Ref: 8bd15382183
Ref: c-api/unicode c PyUnicode_Fill15382674
Ref: 11d115382674
Ref: c-api/unicode c PyUnicode_WriteChar15383177
Ref: 11b615383177
Ref: c-api/unicode c PyUnicode_ReadChar15383878
Ref: 11b515383878
Ref: c-api/unicode c PyUnicode_Substring15384378
Ref: 8be15384378
Ref: c-api/unicode c PyUnicode_AsUCS415384841
Ref: 11bc15384841
Ref: c-api/unicode c PyUnicode_AsUCS4Copy15385366
Ref: 8c315385366
Node: Locale Encoding15385809
Ref: c-api/unicode locale-encoding15385952
Ref: 502015385952
Ref: c-api/unicode c PyUnicode_DecodeLocaleAndSize15386086
Ref: be815386086
Ref: c-api/unicode c PyUnicode_DecodeLocale15387322
Ref: 4dc915387322
Ref: c-api/unicode c PyUnicode_EncodeLocale15387676
Ref: be915387676
Ref: Locale Encoding-Footnote-115388924
Ref: Locale Encoding-Footnote-215388966
Node: File System Encoding15389008
Ref: c-api/unicode file-system-encoding15389128
Ref: 502115389128
Ref: c-api/unicode c PyUnicode_FSConverter15389489
Ref: d4115389489
Ref: c-api/unicode c PyUnicode_FSDecoder15390743
Ref: 57a15390743
Ref: c-api/unicode c PyUnicode_DecodeFSDefaultAndSize15391836
Ref: 4dc715391836
Ref: c-api/unicode c PyUnicode_DecodeFSDefault15392405
Ref: 182715392405
Ref: c-api/unicode c PyUnicode_EncodeFSDefault15392857
Ref: 1be215392857
Ref: File System Encoding-Footnote-115393567
Ref: File System Encoding-Footnote-215393609
Node: wchar_t Support15393651
Ref: c-api/unicode wchar-t-support15393747
Ref: 502215393747
Ref: c-api/unicode c PyUnicode_FromWideChar15393853
Ref: 11d015393853
Ref: c-api/unicode c PyUnicode_AsWideChar15394286
Ref: 1be915394286
Ref: c-api/unicode c PyUnicode_AsWideCharString15395280
Ref: 8c415395280
Node: Built-in Codecs15396411
Ref: c-api/unicode built-in-codecs15396548
Ref: 502315396548
Ref: c-api/unicode builtincodecs15396548
Ref: 501f15396548
Node: Generic Codecs15397771
Ref: c-api/unicode generic-codecs15397858
Ref: 502415397858
Ref: c-api/unicode c PyUnicode_Decode15397942
Ref: 1b7215397942
Ref: c-api/unicode c PyUnicode_AsEncodedString15398522
Ref: 4dbf15398522
Node: UTF-8 Codecs15399083
Ref: c-api/unicode utf-8-codecs15399192
Ref: 502515399192
Ref: c-api/unicode c PyUnicode_DecodeUTF815399270
Ref: 4dd315399270
Ref: c-api/unicode c PyUnicode_DecodeUTF8Stateful15399629
Ref: 18ba15399629
Ref: c-api/unicode c PyUnicode_AsUTF8String15400189
Ref: 11d215400189
Ref: c-api/unicode c PyUnicode_AsUTF8AndSize15400652
Ref: 8a015400652
Ref: c-api/unicode c PyUnicode_AsUTF815401963
Ref: bda15401963
Ref: UTF-8 Codecs-Footnote-115402727
Node: UTF-32 Codecs15402780
Ref: c-api/unicode utf-32-codecs15402888
Ref: 502615402888
Ref: c-api/unicode c PyUnicode_DecodeUTF3215402969
Ref: 4dcf15402969
Ref: c-api/unicode c PyUnicode_DecodeUTF32Stateful15404172
Ref: 4dd015404172
Ref: c-api/unicode c PyUnicode_AsUTF32String15404851
Ref: 4dc115404851
Node: UTF-16 Codecs15405250
Ref: c-api/unicode utf-16-codecs15405358
Ref: 502715405358
Ref: c-api/unicode c PyUnicode_DecodeUTF1615405439
Ref: 4dcd15405439
Ref: c-api/unicode c PyUnicode_DecodeUTF16Stateful15406726
Ref: 4dce15406726
Ref: c-api/unicode c PyUnicode_AsUTF16String15407414
Ref: 4dc015407414
Node: UTF-7 Codecs15407813
Ref: c-api/unicode utf-7-codecs15407929
Ref: 502815407929
Ref: c-api/unicode c PyUnicode_DecodeUTF715408007
Ref: 4dd115408007
Ref: c-api/unicode c PyUnicode_DecodeUTF7Stateful15408366
Ref: 4dd215408366
Node: Unicode-Escape Codecs15408928
Ref: c-api/unicode unicode-escape-codecs15409056
Ref: 502915409056
Ref: c-api/unicode c PyUnicode_DecodeUnicodeEscape15409167
Ref: 4dd415409167
Ref: c-api/unicode c PyUnicode_AsUnicodeEscapeString15409544
Ref: 11d315409544
Node: Raw-Unicode-Escape Codecs15409914
Ref: c-api/unicode raw-unicode-escape-codecs15410044
Ref: 502a15410044
Ref: c-api/unicode c PyUnicode_DecodeRawUnicodeEscape15410167
Ref: 4dcc15410167
Ref: c-api/unicode c PyUnicode_AsRawUnicodeEscapeString15410551
Ref: 11d415410551
Node: Latin-1 Codecs15410928
Ref: c-api/unicode latin-1-codecs15411049
Ref: 502b15411049
Ref: c-api/unicode c PyUnicode_DecodeLatin115411246
Ref: 4dc815411246
Ref: c-api/unicode c PyUnicode_AsLatin1String15411609
Ref: 11d515411609
Node: ASCII Codecs15411970
Ref: c-api/unicode ascii-codecs15412086
Ref: 502c15412086
Ref: c-api/unicode c PyUnicode_DecodeASCII15412234
Ref: 4dc415412234
Ref: c-api/unicode c PyUnicode_AsASCIIString15412594
Ref: 11d615412594
Node: Character Map Codecs15412952
Ref: c-api/unicode character-map-codecs15413077
Ref: 502d15413077
Ref: c-api/unicode c PyUnicode_DecodeCharmap15413557
Ref: 4dc515413557
Ref: c-api/unicode c PyUnicode_AsCharmapString15414449
Ref: 4dbe15414449
Ref: c-api/unicode c PyUnicode_Translate15415228
Ref: 4de115415228
Node: MBCS codecs for Windows15416126
Ref: c-api/unicode mbcs-codecs-for-windows15416230
Ref: 502e15416230
Ref: c-api/unicode c PyUnicode_DecodeMBCS15416590
Ref: 4dca15416590
Ref: c-api/unicode c PyUnicode_DecodeMBCSStateful15416978
Ref: 4dcb15416978
Ref: c-api/unicode c PyUnicode_DecodeCodePageStateful15417540
Ref: 4dc615417540
Ref: c-api/unicode c PyUnicode_AsMBCSString15417951
Ref: 11d715417951
Ref: c-api/unicode c PyUnicode_EncodeCodePage15418337
Ref: 11d815418337
Node: Methods and Slot Functions15418822
Ref: c-api/unicode methods-and-slot-functions15418935
Ref: 502f15418935
Ref: c-api/unicode unicodemethodsandslots15418935
Ref: 503015418935
Ref: c-api/unicode c PyUnicode_Concat15419258
Ref: 11e515419258
Ref: c-api/unicode c PyUnicode_Split15419486
Ref: 4ddf15419486
Ref: c-api/unicode c PyUnicode_RSplit15420107
Ref: 167315420107
Ref: c-api/unicode c PyUnicode_Splitlines15420522
Ref: 4de015420522
Ref: c-api/unicode c PyUnicode_Partition15420935
Ref: 167415420935
Ref: c-api/unicode c PyUnicode_RPartition15421561
Ref: 167515421561
Ref: c-api/unicode c PyUnicode_Join15422115
Ref: 11e615422115
Ref: c-api/unicode c PyUnicode_Tailmatch15422397
Ref: 8c015422397
Ref: c-api/unicode c PyUnicode_Find15422856
Ref: 4dd515422856
Ref: c-api/unicode c PyUnicode_FindChar15423467
Ref: 8c115423467
Ref: c-api/unicode c PyUnicode_Count15424244
Ref: 4dc315424244
Ref: c-api/unicode c PyUnicode_Replace15424564
Ref: 4ddd15424564
Ref: c-api/unicode c PyUnicode_Compare15424983
Ref: 8bf15424983
Ref: c-api/unicode c PyUnicode_EqualToUTF8AndSize15425348
Ref: 37915425348
Ref: c-api/unicode c PyUnicode_EqualToUTF815425951
Ref: 37a15425951
Ref: c-api/unicode c PyUnicode_CompareWithASCIIString15426334
Ref: 12ae15426334
Ref: c-api/unicode c PyUnicode_RichCompare15426836
Ref: 4dde15426836
Ref: c-api/unicode c PyUnicode_Format15427503
Ref: 4dd615427503
Ref: c-api/unicode c PyUnicode_Contains15427784
Ref: 4dc215427784
Ref: c-api/unicode c PyUnicode_InternInPlace15428120
Ref: 8b915428120
Ref: c-api/unicode c PyUnicode_InternFromString15429462
Ref: 170815429462
Node: Tuple Objects15430311
Ref: c-api/tuple doc15430444
Ref: 503115430444
Ref: c-api/tuple translation-repo15430444
Ref: 503215430444
Ref: c-api/tuple tuple-objects15430444
Ref: 503315430444
Ref: c-api/tuple tupleobjects15430444
Ref: 503415430444
Ref: c-api/tuple c PyTupleObject15430491
Ref: 4ed515430491
Ref: c-api/tuple c PyTuple_Type15430605
Ref: 4da115430605
Ref: c-api/tuple c PyTuple_Check15430854
Ref: 503515430854
Ref: c-api/tuple c PyTuple_CheckExact15431030
Ref: 503615431030
Ref: c-api/tuple c PyTuple_New15431217
Ref: 3a015431217
Ref: c-api/tuple c PyTuple_Pack15431459
Ref: 4d9f15431459
Ref: c-api/tuple c PyTuple_Size15431894
Ref: 4da015431894
Ref: c-api/tuple c PyTuple_GET_SIZE15432134
Ref: 503715432134
Ref: c-api/tuple c PyTuple_GetItem15432272
Ref: 4b8215432272
Ref: c-api/tuple c PyTuple_GET_ITEM15432906
Ref: 503815432906
Ref: c-api/tuple c PyTuple_GetSlice15433124
Ref: 4d9e15433124
Ref: c-api/tuple c PyTuple_SetItem15433575
Ref: 4b8315433575
Ref: c-api/tuple c PyTuple_SET_ITEM15434091
Ref: 39015434091
Ref: c-api/tuple c _PyTuple_Resize15434710
Ref: 155b15434710
Node: Struct Sequence Objects15435626
Ref: c-api/tuple id115435745
Ref: 503915435745
Ref: c-api/tuple struct-sequence-objects15435745
Ref: 120415435745
Ref: c-api/tuple c PyStructSequence_NewType15436053
Ref: 4d8115436053
Ref: c-api/tuple c PyStructSequence_InitType15436474
Ref: 103e15436474
Ref: c-api/tuple c PyStructSequence_InitType215436652
Ref: 103d15436652
Ref: c-api/tuple c PyStructSequence_Desc15436923
Ref: bd915436923
Ref: c-api/tuple c PyStructSequence_Desc name15437103
Ref: 503a15437103
Ref: c-api/tuple c PyStructSequence_Desc doc15437266
Ref: 503b15437266
Ref: c-api/tuple c PyStructSequence_Desc fields15437370
Ref: 503c15437370
Ref: c-api/tuple c PyStructSequence_Desc n_in_sequence15437527
Ref: 503d15437527
Ref: c-api/tuple c PyStructSequence_Field15437650
Ref: bd815437650
Ref: c-api/tuple c PyStructSequence_Field name15438060
Ref: 503e15438060
Ref: c-api/tuple c PyStructSequence_Field doc15438261
Ref: 503f15438261
Ref: c-api/tuple c PyStructSequence_UnnamedField15438347
Ref: 98c15438347
Ref: c-api/tuple c PyStructSequence_New15438603
Ref: 4d8015438603
Ref: c-api/tuple c PyStructSequence_GetItem15438942
Ref: 4d7f15438942
Ref: c-api/tuple c PyStructSequence_GET_ITEM15439346
Ref: 504015439346
Ref: c-api/tuple c PyStructSequence_SetItem15439654
Ref: 4d8215439654
Ref: c-api/tuple c PyStructSequence_SET_ITEM15440174
Ref: 504115440174
Node: List Objects15440438
Ref: c-api/list doc15440535
Ref: 504215440535
Ref: c-api/list list-objects15440535
Ref: 504315440535
Ref: c-api/list listobjects15440535
Ref: 504415440535
Ref: c-api/list translation-repo15440535
Ref: 504515440535
Ref: c-api/list c PyListObject15440580
Ref: 4f5815440580
Ref: c-api/list c PyList_Type15440692
Ref: 4ba515440692
Ref: c-api/list c PyList_Check15440941
Ref: 504615440941
Ref: c-api/list c PyList_CheckExact15441114
Ref: 504715441114
Ref: c-api/list c PyList_New15441298
Ref: 4c0b15441298
Ref: c-api/list c PyList_Size15442054
Ref: 146815442054
Ref: c-api/list c PyList_GET_SIZE15442281
Ref: 504815442281
Ref: c-api/list c PyList_GetItemRef15442426
Ref: 35c15442426
Ref: c-api/list c PyList_GetItem15442957
Ref: 35d15442957
Ref: c-api/list c PyList_GET_ITEM15443270
Ref: 4c2115443270
Ref: c-api/list c PyList_SetItem15443481
Ref: 167d15443481
Ref: c-api/list c PyList_SET_ITEM15443974
Ref: 39115443974
Ref: c-api/list c PyList_Insert15444625
Ref: 167c15444625
Ref: c-api/list c PyList_Append15444978
Ref: 4d0215444978
Ref: c-api/list c PyList_GetSlice15445281
Ref: 4d0415445281
Ref: c-api/list c PyList_SetSlice15445726
Ref: 4d0615445726
Ref: c-api/list c PyList_Extend15446236
Ref: 35e15446236
Ref: c-api/list c PyList_Clear15446679
Ref: 35f15446679
Ref: c-api/list c PyList_Sort15447053
Ref: 4d0715447053
Ref: c-api/list c PyList_Reverse15447283
Ref: 4d0515447283
Ref: c-api/list c PyList_AsTuple15447526
Ref: 4d0315447526
Node: Container Objects15447781
Ref: c-api/concrete container-objects15447910
Ref: 504915447910
Ref: c-api/concrete mapobjects15447910
Ref: 504a15447910
Node: Dictionary Objects15448008
Ref: c-api/dict doc15448100
Ref: 504b15448100
Ref: c-api/dict dictionary-objects15448100
Ref: 504c15448100
Ref: c-api/dict dictobjects15448100
Ref: 504d15448100
Ref: c-api/dict c PyDictObject15448155
Ref: 3c415448155
Ref: c-api/dict c PyDict_Type15448273
Ref: 4c8815448273
Ref: c-api/dict c PyDict_Check15448528
Ref: 4f8915448528
Ref: c-api/dict c PyDict_CheckExact15448701
Ref: 504e15448701
Ref: c-api/dict c PyDict_New15448885
Ref: 4c8615448885
Ref: c-api/dict c PyDictProxy_New15449075
Ref: 4c7915449075
Ref: c-api/dict c PyDictProxy_Type15449466
Ref: 4c7a15449466
Ref: c-api/dict c PyDict_Clear15450056
Ref: 4c7f15450056
Ref: c-api/dict c PyDict_Contains15450207
Ref: 33915450207
Ref: c-api/dict c PyDict_ContainsString15450541
Ref: 33815450541
Ref: c-api/dict c PyDict_Copy15450815
Ref: 42315450815
Ref: c-api/dict c PyDict_SetItem15451036
Ref: 4b8415451036
Ref: c-api/dict c PyDict_SetItemString15451443
Ref: 170915451443
Ref: c-api/dict c PyDict_DelItem15451750
Ref: 4c8015451750
Ref: c-api/dict c PyDict_DelItemString15452134
Ref: 4c8115452134
Ref: c-api/dict c PyDict_GetItemRef15452416
Ref: 33b15452416
Ref: c-api/dict c PyDict_GetItem15453047
Ref: 38a15453047
Ref: c-api/dict c PyDict_GetItemWithError15453795
Ref: 33d15453795
Ref: c-api/dict c PyDict_GetItemString15454216
Ref: 38b15454216
Ref: c-api/dict c PyDict_GetItemStringRef15454925
Ref: 33c15454925
Ref: c-api/dict c PyDict_SetDefault15455286
Ref: 34115455286
Ref: c-api/dict c PyDict_SetDefaultRef15455891
Ref: 34015455891
Ref: c-api/dict c PyDict_Pop15456989
Ref: 34215456989
Ref: c-api/dict c PyDict_PopString15457719
Ref: 34315457719
Ref: c-api/dict c PyDict_Items15458003
Ref: 4c8215458003
Ref: c-api/dict c PyDict_Keys15458235
Ref: 4c8315458235
Ref: c-api/dict c PyDict_Values15458465
Ref: 4c8a15458465
Ref: c-api/dict c PyDict_Size15458703
Ref: 4c8715458703
Ref: c-api/dict c PyDict_GET_SIZE15458922
Ref: 504f15458922
Ref: c-api/dict c PyDict_Next15459064
Ref: 171b15459064
Ref: c-api/dict c PyDict_Merge15461427
Ref: 4c8415461427
Ref: c-api/dict c PyDict_Update15462014
Ref: 4c8915462014
Ref: c-api/dict c PyDict_MergeFromSeq215462477
Ref: 4c8515462477
Ref: c-api/dict c PyDict_AddWatcher15463203
Ref: 56515463203
Ref: c-api/dict c PyDict_ClearWatcher15463565
Ref: 505115463565
Ref: c-api/dict c PyDict_Watch15463868
Ref: 56615463868
Ref: c-api/dict c PyDict_Unwatch15464194
Ref: 505215464194
Ref: c-api/dict c PyDict_WatchEvent15464608
Ref: 505315464608
Ref: c-api/dict c PyDict_WatchCallback15464918
Ref: 505415464918
Node: Dictionary View Objects15467248
Ref: c-api/dict dictionary-view-objects15467355
Ref: 505515467355
Ref: c-api/dict c PyDictViewSet_Check15467420
Ref: 505615467420
Ref: c-api/dict c PyDictKeys_Type15467708
Ref: 4c7815467708
Ref: c-api/dict c PyDictKeys_Check15467942
Ref: 505715467942
Ref: c-api/dict c PyDictValues_Type15468100
Ref: 4c7e15468100
Ref: c-api/dict c PyDictValues_Check15468340
Ref: 505915468340
Ref: c-api/dict c PyDictItems_Type15468501
Ref: 4c7415468501
Ref: c-api/dict c PyDictItems_Check15468738
Ref: 505815468738
Node: Ordered Dictionaries15468897
Ref: c-api/dict ordered-dictionaries15469004
Ref: 505a15469004
Ref: c-api/dict c PyODict_Type15469293
Ref: 505b15469293
Ref: c-api/dict c PyODict_Check15469482
Ref: 505c15469482
Ref: c-api/dict c PyODict_CheckExact15469697
Ref: 505d15469697
Ref: c-api/dict c PyODictKeys_Type15469923
Ref: 505e15469923
Ref: c-api/dict c PyODictValues_Type15470056
Ref: 505f15470056
Ref: c-api/dict c PyODictItems_Type15470198
Ref: 506015470198
Ref: c-api/dict c PyODict_New15470338
Ref: 506115470338
Ref: c-api/dict c PyODict_SetItem15470520
Ref: 506215470520
Ref: c-api/dict c PyODict_DelItem15470829
Ref: 506315470829
Ref: c-api/dict c PyODict_GetItem15471502
Ref: 506415471502
Ref: c-api/dict c PyODict_GetItemWithError15471707
Ref: 506515471707
Ref: c-api/dict c PyODict_GetItemString15471909
Ref: 506615471909
Ref: c-api/dict c PyODict_Contains15472106
Ref: 506715472106
Ref: c-api/dict c PyODict_Size15472294
Ref: 506815472294
Ref: c-api/dict c PyODict_SIZE15472488
Ref: 506915472488
Node: Set Objects15472601
Ref: c-api/set doc15472693
Ref: 506a15472693
Ref: c-api/set set-objects15472693
Ref: 506b15472693
Ref: c-api/set setobjects15472693
Ref: 506c15472693
Ref: c-api/set translation-repo15472693
Ref: 506d15472693
Ref: c-api/set c PySetObject15473470
Ref: 506e15473470
Ref: c-api/set c PySet_Type15474110
Ref: 4d7815474110
Ref: c-api/set c PyFrozenSet_Type15474306
Ref: 4cee15474306
Ref: c-api/set c PySet_Check15474665
Ref: 506f15474665
Ref: c-api/set c PyFrozenSet_Check15474831
Ref: 507015474831
Ref: c-api/set c PyAnySet_Check15475009
Ref: 507115475009
Ref: c-api/set c PySet_CheckExact15475216
Ref: 8a415475216
Ref: c-api/set c PyAnySet_CheckExact15475421
Ref: 507215475421
Ref: c-api/set c PyFrozenSet_CheckExact15475639
Ref: 507315475639
Ref: c-api/set c PySet_New15475827
Ref: 149315475827
Ref: c-api/set c PyFrozenSet_New15476328
Ref: 149415476328
Ref: c-api/set c PySet_Size15476929
Ref: 149815476929
Ref: c-api/set c PySet_GET_SIZE15477281
Ref: 507415477281
Ref: c-api/set c PySet_Contains15477425
Ref: 149715477425
Ref: c-api/set c PySet_Add15477977
Ref: 149515477977
Ref: c-api/set c PySet_Discard15478766
Ref: 149615478766
Ref: c-api/set c PySet_Pop15479374
Ref: 4d7715479374
Ref: c-api/set c PySet_Clear15479813
Ref: 4d7615479813
Node: Function Objects<2>15480102
Ref: c-api/concrete function-objects15480228
Ref: 507515480228
Ref: c-api/concrete otherobjects15480228
Ref: 507615480228
Node: Function Objects<3>15480485
Ref: c-api/function doc15480592
Ref: 507715480592
Ref: c-api/function function-objects15480592
Ref: 507815480592
Ref: c-api/function id115480592
Ref: 507915480592
Ref: c-api/function c PyFunctionObject15480700
Ref: 56415480700
Ref: c-api/function c PyFunction_Type15480777
Ref: 507a15480777
Ref: c-api/function c PyFunction_Check15481006
Ref: 507b15481006
Ref: c-api/function c PyFunction_New15481226
Ref: 507c15481226
Ref: c-api/function c PyFunction_NewWithQualName15481857
Ref: 507d15481857
Ref: c-api/function c PyFunction_GetCode15482374
Ref: 507e15482374
Ref: c-api/function c PyFunction_GetGlobals15482559
Ref: 507f15482559
Ref: c-api/function c PyFunction_GetModule15482764
Ref: 508015482764
Ref: c-api/function c PyFunction_GetDefaults15483170
Ref: 508115483170
Ref: c-api/function c PyFunction_SetDefaults15483422
Ref: 508215483422
Ref: c-api/function c PyFunction_SetVectorcall15483699
Ref: 56315483699
Ref: c-api/function c PyFunction_GetKwDefaults15484024
Ref: 508315484024
Ref: c-api/function c PyFunction_SetKwDefaults15484296
Ref: 508415484296
Ref: c-api/function c PyFunction_GetClosure15484662
Ref: 508515484662
Ref: c-api/function c PyFunction_SetClosure15484913
Ref: 508615484913
Ref: c-api/function c PyFunction_GetAnnotations15485199
Ref: 18da15485199
Ref: c-api/function c PyFunction_SetAnnotations15485437
Ref: 508715485437
Ref: c-api/function c PyFunction_GET_CODE15485717
Ref: 508815485717
Ref: c-api/function c PyFunction_GET_GLOBALS15485790
Ref: 508915485790
Ref: c-api/function c PyFunction_GET_MODULE15485876
Ref: 508a15485876
Ref: c-api/function c PyFunction_GET_DEFAULTS15485961
Ref: 508b15485961
Ref: c-api/function c PyFunction_GET_KW_DEFAULTS15486048
Ref: 508c15486048
Ref: c-api/function c PyFunction_GET_CLOSURE15486138
Ref: 508d15486138
Ref: c-api/function c PyFunction_GET_ANNOTATIONS15486224
Ref: 508e15486224
Ref: c-api/function c PyFunction_AddWatcher15486569
Ref: 508f15486569
Ref: c-api/function c PyFunction_ClearWatcher15486950
Ref: 509015486950
Ref: c-api/function c PyFunction_WatchEvent15487318
Ref: 509115487318
Ref: c-api/function c PyFunction_WatchCallback15487703
Ref: 509215487703
Node: Instance Method Objects15489906
Ref: c-api/method doc15490039
Ref: 509315490039
Ref: c-api/method instance-method-objects15490039
Ref: 509415490039
Ref: c-api/method instancemethod-objects15490039
Ref: 509515490039
Ref: c-api/method translation-repo15490039
Ref: 509615490039
Ref: c-api/method c PyInstanceMethod_Type15490299
Ref: 509715490299
Ref: c-api/method c PyInstanceMethod_Check15490499
Ref: 509815490499
Ref: c-api/method c PyInstanceMethod_New15490738
Ref: 509915490738
Ref: c-api/method c PyInstanceMethod_Function15491028
Ref: 509a15491028
Ref: c-api/method c PyInstanceMethod_GET_FUNCTION15491234
Ref: 509b15491234
Node: Method Objects<2>15491462
Ref: c-api/method id115491588
Ref: 509c15491588
Ref: c-api/method method-objects15491588
Ref: 509d15491588
Ref: c-api/method c PyMethod_Type15491814
Ref: 509e15491814
Ref: c-api/method c PyMethod_Check15492026
Ref: 509f15492026
Ref: c-api/method c PyMethod_New15492240
Ref: 50a015492240
Ref: c-api/method c PyMethod_Function15492608
Ref: 50a115492608
Ref: c-api/method c PyMethod_GET_FUNCTION15492791
Ref: 50a215492791
Ref: c-api/method c PyMethod_Self15493005
Ref: 50a315493005
Ref: c-api/method c PyMethod_GET_SELF15493177
Ref: 50a415493177
Node: Cell Objects15493373
Ref: c-api/cell doc15493491
Ref: 50a515493491
Ref: c-api/cell cell-objects15493491
Ref: 70415493491
Ref: c-api/cell id115493491
Ref: 50a615493491
Ref: c-api/cell translation-repo15493491
Ref: 50a715493491
Ref: c-api/cell c PyCellObject15494135
Ref: 50a815494135
Ref: c-api/cell c PyCell_Type15494211
Ref: 50a915494211
Ref: c-api/cell c PyCell_Check15494318
Ref: 50aa15494318
Ref: c-api/cell c PyCell_New15494476
Ref: 50ab15494476
Ref: c-api/cell c PyCell_Get15494680
Ref: 50ac15494680
Ref: c-api/cell c PyCell_GET15494934
Ref: 50ad15494934
Ref: c-api/cell c PyCell_Set15495163
Ref: 50ae15495163
Ref: c-api/cell c PyCell_SET15495535
Ref: 8b615495535
Node: Code Objects<2>15495798
Ref: c-api/code doc15495916
Ref: 50af15495916
Ref: c-api/code code-objects15495916
Ref: 50b015495916
Ref: c-api/code codeobjects15495916
Ref: 5b815495916
Ref: c-api/code translation-repo15495916
Ref: 50b115495916
Ref: c-api/code c PyCodeObject15496121
Ref: 77a15496121
Ref: c-api/code c PyCode_Type15496285
Ref: 50b215496285
Ref: c-api/code c PyCode_Check15496446
Ref: 50b315496446
Ref: c-api/code c PyCode_GetNumFree15496587
Ref: 50b415496587
Ref: c-api/code c PyUnstable_Code_GetFirstFree15496762
Ref: 38915496762
Ref: c-api/code c PyUnstable_Code_New15497305
Ref: 50b515497305
Ref: c-api/code c PyCode_NewWithPosOnlyArgs15498712
Ref: 50b615498712
Ref: c-api/code c PyUnstable_Code_NewWithPosOnlyArgs15498712
Ref: 50b715498712
Ref: c-api/code c PyCode_NewEmpty15499914
Ref: 139c15499914
Ref: c-api/code c PyCode_Addr2Line15500260
Ref: 89015500260
Ref: c-api/code c PyCode_Addr2Location15500663
Ref: 5b715500663
Ref: c-api/code c PyCode_GetCode15501143
Ref: 77b15501143
Ref: c-api/code c PyCode_GetVarnames15501727
Ref: 77c15501727
Ref: c-api/code c PyCode_GetCellvars15502091
Ref: 77d15502091
Ref: c-api/code c PyCode_GetFreevars15502500
Ref: 77e15502500
Ref: c-api/code c PyCode_AddWatcher15502885
Ref: 56915502885
Ref: c-api/code c PyCode_ClearWatcher15503246
Ref: 56a15503246
Ref: c-api/code c PyCodeEvent15503605
Ref: 50b815503605
Ref: c-api/code c PyCode_WatchCallback15503786
Ref: 50b915503786
Ref: c-api/code c PyCode_Optimize15505566
Ref: 50ba15505566
Ref: Code Objects<2>-Footnote-115505975
Node: Code Object Flags15506057
Ref: c-api/code c-codeobject-flags15506180
Ref: 4e9f15506180
Ref: c-api/code code-object-flags15506180
Ref: 50bb15506180
Ref: c-api/code c CO_OPTIMIZED15507228
Ref: 50bc15507228
Ref: c-api/code c CO_NEWLOCALS15507429
Ref: 50bd15507429
Ref: c-api/code c CO_VARARGS15507628
Ref: 50be15507628
Ref: c-api/code c CO_VARKEYWORDS15507831
Ref: 50bf15507831
Ref: c-api/code c CO_NESTED15508029
Ref: 50c015508029
Ref: c-api/code c CO_GENERATOR15508230
Ref: 50c115508230
Ref: c-api/code c CO_COROUTINE15508431
Ref: 50c215508431
Ref: c-api/code c CO_ITERABLE_COROUTINE15508641
Ref: 50c315508641
Ref: c-api/code c CO_ASYNC_GENERATOR15508848
Ref: 50c415508848
Ref: c-api/code c CO_FUTURE_DIVISION15509055
Ref: 50c515509055
Ref: c-api/code c CO_FUTURE_ABSOLUTE_IMPORT15509274
Ref: 50c615509274
Ref: c-api/code c CO_FUTURE_WITH_STATEMENT15509492
Ref: 50c715509492
Ref: c-api/code c CO_FUTURE_PRINT_FUNCTION15509710
Ref: 50c815509710
Ref: c-api/code c CO_FUTURE_UNICODE_LITERALS15509930
Ref: 50c915509930
Ref: c-api/code c CO_FUTURE_GENERATOR_STOP15510148
Ref: 50ca15510148
Ref: c-api/code c CO_FUTURE_ANNOTATIONS15510363
Ref: 4e9e15510363
Node: Extra information15510477
Ref: c-api/code extra-information15510576
Ref: 50cb15510576
Ref: c-api/code c _PyEval_RequestCodeExtraIndex15510949
Ref: 50cc15510949
Ref: c-api/code c PyUnstable_Eval_RequestCodeExtraIndex15510949
Ref: 50cd15510949
Ref: c-api/code c _PyCode_GetExtra15511954
Ref: 50ce15511954
Ref: c-api/code c PyUnstable_Code_GetExtra15511954
Ref: 50cf15511954
Ref: c-api/code c _PyCode_SetExtra15512698
Ref: 50d015512698
Ref: c-api/code c PyUnstable_Code_SetExtra15512698
Ref: 50d115512698
Node: Other Objects15513325
Ref: c-api/concrete other-objects15513461
Ref: 50d215513461
Node: File Objects15513879
Ref: c-api/file doc15513964
Ref: 50d315513964
Ref: c-api/file file-objects15513964
Ref: 50d415513964
Ref: c-api/file fileobjects15513964
Ref: 50d515513964
Ref: c-api/file c PyFile_FromFd15514540
Ref: 4ce615514540
Ref: c-api/file c PyObject_AsFileDescriptor15515551
Ref: 4d4d15515551
Ref: c-api/file c PyFile_GetLine15516004
Ref: 4ce715516004
Ref: c-api/file c PyFile_SetOpenCodeHook15516837
Ref: 183a15516837
Ref: c-api/file c Py_OpenCodeHookFunction15517092
Ref: 50d615517092
Ref: c-api/file c PyFile_OpenCodeObject15518190
Ref: 50d715518190
Ref: c-api/file c PyFile_OpenCode15518790
Ref: 50d815518790
Ref: c-api/file c PyFile_WriteObject15518994
Ref: 4ce815518994
Ref: c-api/file c PyFile_WriteString15519503
Ref: 4ce915519503
Node: Module Objects15519753
Ref: c-api/module doc15519863
Ref: 50d915519863
Ref: c-api/module module-objects15519863
Ref: 50da15519863
Ref: c-api/module moduleobjects15519863
Ref: 50db15519863
Ref: c-api/module translation-repo15519863
Ref: 50dc15519863
Ref: c-api/module c PyModule_Type15519910
Ref: 4d2915519910
Ref: c-api/module c PyModule_Check15520170
Ref: 50dd15520170
Ref: c-api/module c PyModule_CheckExact15520335
Ref: 50de15520335
Ref: c-api/module c PyModule_NewObject15520520
Ref: 4d2715520520
Ref: c-api/module c PyModule_New15521253
Ref: 4d2615521253
Ref: c-api/module c PyModule_GetDict15521522
Ref: 4d2315521522
Ref: c-api/module c PyModule_GetNameObject15522278
Ref: 4d2515522278
Ref: c-api/module c PyModule_GetName15522685
Ref: 4d2415522685
Ref: c-api/module c PyModule_GetState15523082
Ref: 98a15523082
Ref: c-api/module c PyModule_GetDef15523367
Ref: 4d2215523367
Ref: c-api/module c PyModule_GetFilenameObject15523822
Ref: 3fc15523822
Ref: c-api/module c PyModule_GetFilename15524315
Ref: 3fb15524315
Node: Initializing C modules15524932
Ref: c-api/module initializing-c-modules15525027
Ref: 50df15525027
Ref: c-api/module initializing-modules15525027
Ref: 4bc715525027
Ref: c-api/module c PyModuleDef15525661
Ref: 98715525661
Ref: c-api/module c PyModuleDef m_base15525956
Ref: 50e115525956
Ref: c-api/module c PyModuleDef m_name15526073
Ref: 50e215526073
Ref: c-api/module c PyModuleDef m_doc15526148
Ref: 50e315526148
Ref: c-api/module c PyModuleDef m_size15526310
Ref: 98915526310
Ref: c-api/module c PyModuleDef m_methods15527281
Ref: 50e415527281
Ref: c-api/module c PyModuleDef m_slots15527510
Ref: 50e515527510
Ref: c-api/module c PyModuleDef m_slots m_reload15527900
Ref: 50e615527900
Ref: c-api/module c PyModuleDef m_traverse15527960
Ref: 98415527960
Ref: c-api/module c PyModuleDef m_clear15528695
Ref: 98515528695
Ref: c-api/module c PyModuleDef m_free15529760
Ref: 98615529760
Ref: c-api/module c PyModuleDef_Type15530477
Ref: 4d1f15530477
Ref: Initializing C modules-Footnote-115530814
Node: Single-phase initialization15530856
Ref: c-api/module single-phase-initialization15530977
Ref: 50e815530977
Ref: c-api/module c PyModule_Create15531256
Ref: 50e015531256
Ref: c-api/module c PyModule_Create215531551
Ref: 4d2115531551
Node: Multi-phase initialization15532361
Ref: c-api/module id115532526
Ref: 50e915532526
Ref: c-api/module multi-phase-initialization15532526
Ref: 4bc815532526
Ref: c-api/module c PyModuleDef_Init15534749
Ref: 4b6d15534749
Ref: c-api/module c PyModuleDef_Slot15535286
Ref: 4d1e15535286
Ref: c-api/module c PyModuleDef_Slot slot15535410
Ref: 50eb15535410
Ref: c-api/module c PyModuleDef_Slot value15535512
Ref: 50ec15535512
Ref: c-api/module c Py_mod_create15535732
Ref: 4e1015535732
Ref: c-api/module c Py_mod_create create_module15535987
Ref: 50ed15535987
Ref: c-api/module c Py_mod_exec15537446
Ref: 98815537446
Ref: c-api/module c Py_mod_exec exec_module15537780
Ref: 50ee15537780
Ref: c-api/module c Py_mod_multiple_interpreters15537995
Ref: 4e1115537995
Ref: c-api/module c Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED15538145
Ref: 4b6f15538145
Ref: c-api/module c Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED15538281
Ref: 50ef15538281
Ref: c-api/module c Py_MOD_PER_INTERPRETER_GIL_SUPPORTED15538527
Ref: 50f015538527
Ref: c-api/module c Py_mod_gil15539134
Ref: 15815539134
Ref: c-api/module c Py_MOD_GIL_USED15539266
Ref: 50f115539266
Ref: c-api/module c Py_MOD_GIL_NOT_USED15539458
Ref: 50f215539458
Ref: Multi-phase initialization-Footnote-115540152
Ref: Multi-phase initialization-Footnote-215540194
Node: Low-level module creation functions15540236
Ref: c-api/module low-level-module-creation-functions15540391
Ref: 50f315540391
Ref: c-api/module c PyModule_FromDefAndSpec15540770
Ref: ee715540770
Ref: c-api/module c PyModule_FromDefAndSpec215541160
Ref: ee815541160
Ref: c-api/module c PyModule_ExecDef15541911
Ref: ee915541911
Ref: c-api/module c PyModule_SetDocString15542162
Ref: 4d2815542162
Ref: c-api/module c PyModule_AddFunctions15542647
Ref: 4d2015542647
Node: Support functions15543521
Ref: c-api/module support-functions15543641
Ref: 50f415543641
Ref: c-api/module c PyModule_AddObjectRef15543927
Ref: 36815543927
Ref: c-api/module c PyModule_Add15545850
Ref: 36715545850
Ref: c-api/module c PyModule_AddObject15546430
Ref: 36915546430
Ref: c-api/module c PyModule_AddIntConstant15547868
Ref: 158c15547868
Ref: c-api/module c PyModule_AddStringConstant15548398
Ref: 158d15548398
Ref: c-api/module c PyModule_AddIntMacro15549003
Ref: 144115549003
Ref: c-api/module c PyModule_AddStringMacro15549360
Ref: 144015549360
Ref: c-api/module c PyModule_AddType15549455
Ref: 97f15549455
Ref: c-api/module c PyUnstable_Module_SetGIL15549929
Ref: 17915549929
Node: Module lookup15550769
Ref: c-api/module module-lookup15550864
Ref: 50f515550864
Ref: c-api/module c PyState_FindModule15551283
Ref: 4d7d15551283
Ref: c-api/module c PyState_AddModule15551833
Ref: 4d7c15551833
Ref: c-api/module c PyState_RemoveModule15552872
Ref: 4d7e15552872
Node: Iterator Objects15553211
Ref: c-api/iterator doc15553327
Ref: 50f615553327
Ref: c-api/iterator id115553327
Ref: 50f715553327
Ref: c-api/iterator iterator-objects15553327
Ref: 50f815553327
Ref: c-api/iterator translation-repo15553327
Ref: 50f915553327
Ref: c-api/iterator c PySeqIter_Type15553725
Ref: 4d6515553725
Ref: c-api/iterator c PySeqIter_Check15554014
Ref: 50fa15554014
Ref: c-api/iterator c PySeqIter_New15554171
Ref: 4d6415554171
Ref: c-api/iterator c PyCallIter_Type15554500
Ref: 4c5315554500
Ref: c-api/iterator c PyCallIter_Check15554758
Ref: 50fb15554758
Ref: c-api/iterator c PyCallIter_New15554917
Ref: 4c5215554917
Node: Range Objects15555484
Ref: c-api/iterator range-objects15555581
Ref: 50fc15555581
Ref: c-api/iterator c PyRange_Type15555628
Ref: 4d6215555628
Ref: c-api/iterator c PyRange_Check15555779
Ref: 50fd15555779
Node: Builtin Iterator Types15555947
Ref: c-api/iterator builtin-iterator-types15556075
Ref: 50fe15556075
Ref: c-api/iterator c PyEnum_Type15556627
Ref: 4c8c15556627
Ref: c-api/iterator c PyFilter_Type15556750
Ref: 4cea15556750
Ref: c-api/iterator c PyMap_Type15556935
Ref: 4d1515556935
Ref: c-api/iterator c PyReversed_Type15557052
Ref: 4d6315557052
Ref: c-api/iterator c PyZip_Type15557239
Ref: 4de715557239
Node: Other Iterator Objects15557316
Ref: c-api/iterator other-iterator-objects15557422
Ref: 50ff15557422
Ref: c-api/iterator c PyByteArrayIter_Type15557487
Ref: 4c3a15557487
Ref: c-api/iterator c PyBytesIter_Type15557593
Ref: 4c4015557593
Ref: c-api/iterator c PyListIter_Type15557695
Ref: 4d0015557695
Ref: c-api/iterator c PyListRevIter_Type15557796
Ref: 4d0115557796
Ref: c-api/iterator c PySetIter_Type15557900
Ref: 4d7515557900
Ref: c-api/iterator c PyTupleIter_Type15558000
Ref: 4d9d15558000
Ref: c-api/iterator c PyRangeIter_Type15558102
Ref: 4d6115558102
Ref: c-api/iterator c PyLongRangeIter_Type15558204
Ref: 4d0815558204
Ref: c-api/iterator c PyDictIterKey_Type15558310
Ref: 4c7615558310
Ref: c-api/iterator c PyDictRevIterKey_Type15558414
Ref: 4c7c15558414
Ref: c-api/iterator c PyDictIterValue_Type15558540
Ref: 4c7715558540
Ref: c-api/iterator c PyDictRevIterValue_Type15558646
Ref: 4c7d15558646
Ref: c-api/iterator c PyDictIterItem_Type15558774
Ref: 4c7515558774
Ref: c-api/iterator c PyDictRevIterItem_Type15558879
Ref: 4c7b15558879
Ref: c-api/iterator c PyODictIter_Type15559006
Ref: 510015559006
Node: Descriptor Objects15559546
Ref: c-api/descriptor doc15559661
Ref: 510115559661
Ref: c-api/descriptor descriptor-objects15559661
Ref: 510215559661
Ref: c-api/descriptor id115559661
Ref: 510315559661
Ref: c-api/descriptor translation-repo15559661
Ref: 510415559661
Ref: c-api/descriptor c PyProperty_Type15559842
Ref: 4d6015559842
Ref: c-api/descriptor c PyDescr_NewGetSet15560000
Ref: 4c7215560000
Ref: c-api/descriptor c PyDescr_NewMember15560195
Ref: 4c7315560195
Ref: c-api/descriptor c PyMemberDescr_Type15560388
Ref: 4d1915560388
Ref: c-api/descriptor c PyGetSetDescr_Type15560756
Ref: 4cf115560756
Ref: c-api/descriptor c PyDescr_NewMethod15561122
Ref: 1b1e15561122
Ref: c-api/descriptor c PyMethodDescr_Type15561315
Ref: 4d1d15561315
Ref: c-api/descriptor c PyDescr_NewWrapper15561673
Ref: 510515561673
Ref: c-api/descriptor c PyWrapperDescr_Type15561842
Ref: 4de515561842
Ref: c-api/descriptor c PyDescr_NewClassMethod15562274
Ref: 4c7115562274
Ref: c-api/descriptor c PyDescr_IsData15562467
Ref: 1a5915562467
Ref: c-api/descriptor c PyWrapper_New15562717
Ref: 4de615562717
Node: Built-in descriptors15562917
Ref: c-api/descriptor built-in-descriptors15562992
Ref: 510615562992
Ref: c-api/descriptor c PySuper_Type15563053
Ref: 4d8315563053
Ref: c-api/descriptor c PyClassMethod_Type15563264
Ref: 510715563264
Ref: c-api/descriptor c PyClassMethodDescr_Type15563443
Ref: 4c5f15563443
Ref: c-api/descriptor c PyClassMethod_New15563800
Ref: 510815563800
Ref: c-api/descriptor c PyStaticMethod_Type15564213
Ref: 510915564213
Ref: c-api/descriptor c PyStaticMethod_New15564395
Ref: 510a15564395
Node: Slice Objects15564811
Ref: c-api/slice doc15564928
Ref: 510b15564928
Ref: c-api/slice id115564928
Ref: 510c15564928
Ref: c-api/slice slice-objects15564928
Ref: 510d15564928
Ref: c-api/slice translation-repo15564928
Ref: 510e15564928
Ref: c-api/slice c PySlice_Type15564975
Ref: 4d7b15564975
Ref: c-api/slice c PySlice_Check15565179
Ref: 510f15565179
Ref: c-api/slice c PySlice_New15565339
Ref: 4d7a15565339
Ref: c-api/slice c PySlice_GetIndices15565922
Ref: 4d7915565922
Ref: c-api/slice c PySlice_GetIndicesEx15566685
Ref: 3ff15566685
Ref: c-api/slice c PySlice_Unpack15568689
Ref: 40015568689
Ref: c-api/slice c PySlice_AdjustIndices15569353
Ref: 40115569353
Node: Ellipsis Object15569899
Ref: c-api/slice ellipsis-object15569964
Ref: 511015569964
Ref: c-api/slice c PyEllipsis_Type15570015
Ref: 4c8b15570015
Ref: c-api/slice c Py_Ellipsis15570238
Ref: 511115570238
Ref: c-api/memoryview memoryview-objects15570513
Ref: 4f6e15570513
Node: MemoryView objects15570513
Ref: c-api/memoryview doc15570633
Ref: 511215570633
Ref: c-api/memoryview id115570633
Ref: 511315570633
Ref: c-api/memoryview translation-repo15570633
Ref: 511415570633
Ref: c-api/memoryview c PyMemoryView_Type15570846
Ref: 4d1c15570846
Ref: c-api/memoryview c PyMemoryView_FromObject15571113
Ref: 4d1a15571113
Ref: c-api/memoryview c PyBUF_READ15571547
Ref: 17a315571547
Ref: c-api/memoryview c PyBUF_WRITE15571676
Ref: 17a415571676
Ref: c-api/memoryview c PyMemoryView_FromMemory15571806
Ref: 11b415571806
Ref: c-api/memoryview c PyMemoryView_FromBuffer15572196
Ref: 76415572196
Ref: c-api/memoryview c PyMemoryView_GetContiguous15572566
Ref: 4d1b15572566
Ref: c-api/memoryview c PyMemoryView_Check15573198
Ref: 511515573198
Ref: c-api/memoryview c PyMemoryView_GET_BUFFER15573433
Ref: 511615573433
Ref: c-api/memoryview c PyMemoryView_GET_BASE15573755
Ref: 511715573755
Ref: c-api/picklebuffer picklebuffer-objects15574145
Ref: 511815574145
Node: Pickle buffer objects15574145
Ref: c-api/picklebuffer doc15574277
Ref: 511915574277
Ref: c-api/picklebuffer pickle-buffer-objects15574277
Ref: 511a15574277
Ref: c-api/picklebuffer translation-repo15574277
Ref: 511b15574277
Ref: c-api/picklebuffer c PyPickleBuffer_Type15574515
Ref: 511c15574515
Ref: c-api/picklebuffer c PyPickleBuffer_Check15574759
Ref: 511d15574759
Ref: c-api/picklebuffer c PyPickleBuffer_FromObject15574908
Ref: 511e15574908
Ref: c-api/picklebuffer c PyPickleBuffer_GetBuffer15575345
Ref: 511f15575345
Ref: c-api/picklebuffer c PyPickleBuffer_Release15575907
Ref: 512015575907
Node: Weak Reference Objects<2>15576211
Ref: c-api/weakref doc15576336
Ref: 512115576336
Ref: c-api/weakref translation-repo15576336
Ref: 512215576336
Ref: c-api/weakref weak-reference-objects15576336
Ref: 512315576336
Ref: c-api/weakref weakrefobjects15576336
Ref: 4f9915576336
Ref: c-api/weakref c PyWeakref_Check15576654
Ref: 512415576654
Ref: c-api/weakref c PyWeakref_CheckRef15576811
Ref: 512515576811
Ref: c-api/weakref c PyWeakref_CheckRefExact15576992
Ref: 512615576992
Ref: c-api/weakref c PyWeakref_CheckProxy15577184
Ref: 512715577184
Ref: c-api/weakref c PyWeakref_NewRef15577327
Ref: 198a15577327
Ref: c-api/weakref c PyWeakref_NewProxy15578287
Ref: 4de415578287
Ref: c-api/weakref c PyWeakref_GetRef15579250
Ref: 37b15579250
Ref: c-api/weakref c PyWeakref_GetObject15579782
Ref: 37c15579782
Ref: c-api/weakref c PyWeakref_GET_OBJECT15580535
Ref: 3c215580535
Ref: c-api/weakref c PyObject_ClearWeakRefs15580860
Ref: 57915580860
Ref: c-api/weakref c PyUnstable_Object_ClearWeakRefsNoCallbacks15581242
Ref: 171c15581242
Node: Capsules<2>15582142
Ref: c-api/capsule doc15582259
Ref: 512815582259
Ref: c-api/capsule capsules15582259
Ref: 274015582259
Ref: c-api/capsule id115582259
Ref: 512915582259
Ref: c-api/capsule translation-repo15582259
Ref: 512a15582259
Ref: c-api/capsule c PyCapsule15582429
Ref: 12b915582429
Ref: c-api/capsule c PyCapsule_Type15582874
Ref: 4c5e15582874
Ref: c-api/capsule c PyCapsule_Destructor15583115
Ref: 4c5515583115
Ref: c-api/capsule c PyCapsule_CheckExact15583423
Ref: 512b15583423
Ref: c-api/capsule c PyCapsule_New15583578
Ref: 4b8e15583578
Ref: c-api/capsule c PyCapsule_GetPointer15584541
Ref: 4c5915584541
Ref: c-api/capsule c PyCapsule_GetDestructor15585049
Ref: 4c5715585049
Ref: c-api/capsule c PyCapsule_GetContext15585538
Ref: 4c5615585538
Ref: c-api/capsule c PyCapsule_GetName15585980
Ref: 4c5815585980
Ref: c-api/capsule c PyCapsule_Import15586419
Ref: 19b415586419
Ref: c-api/capsule c PyCapsule_IsValid15587430
Ref: 13a915587430
Ref: c-api/capsule c PyCapsule_SetContext15588251
Ref: 4c5a15588251
Ref: c-api/capsule c PyCapsule_SetDestructor15588529
Ref: 4c5b15588529
Ref: c-api/capsule c PyCapsule_SetName15588826
Ref: 4c5c15588826
Ref: c-api/capsule c PyCapsule_SetPointer15589252
Ref: 4c5d15589252
Node: Frame Objects15589563
Ref: c-api/frame doc15589672
Ref: 512c15589672
Ref: c-api/frame frame-objects15589672
Ref: 512d15589672
Ref: c-api/frame translation-repo15589672
Ref: 512e15589672
Ref: c-api/frame c PyFrameObject15589719
Ref: 78c15589719
Ref: c-api/frame c PyFrame_Type15590260
Ref: 78a15590260
Ref: c-api/frame c PyFrame_New15590545
Ref: 189215590545
Ref: c-api/frame c PyFrame_Check15590892
Ref: 78815590892
Ref: c-api/frame c PyFrame_GetBack15591113
Ref: 78915591113
Ref: c-api/frame c PyFrame_GetBuiltins15591427
Ref: 76e15591427
Ref: c-api/frame c PyFrame_GetCode15591723
Ref: 78d15591723
Ref: c-api/frame c PyFrame_GetGenerator15592061
Ref: 76f15592061
Ref: c-api/frame c PyFrame_GetGlobals15592492
Ref: 77015592492
Ref: c-api/frame c PyFrame_GetLasti15592786
Ref: 77115592786
Ref: c-api/frame c PyFrame_GetVar15592988
Ref: 56b15592988
Ref: c-api/frame c PyFrame_GetVarString15593495
Ref: 56c15593495
Ref: c-api/frame c PyFrame_GetLocals15593771
Ref: 42215593771
Ref: c-api/frame c PyFrame_GetLineNumber15594483
Ref: 78e15594483
Ref: Frame Objects-Footnote-115594800
Node: Frame Locals Proxies15594842
Ref: c-api/frame frame-locals-proxies15594947
Ref: 513015594947
Ref: c-api/frame c PyFrameLocalsProxy_Type15595411
Ref: 512f15595411
Ref: c-api/frame c PyFrameLocalsProxy_Check15595537
Ref: 513115595537
Ref: Frame Locals Proxies-Footnote-115595705
Node: Legacy Local Variable APIs15595747
Ref: c-api/frame legacy-local-variable-apis15595876
Ref: 513215595876
Ref: c-api/frame c PyFrame_LocalsToFast15596078
Ref: 513315596078
Ref: c-api/frame c PyFrame_FastToLocals15596621
Ref: 513415596621
Ref: c-api/frame c PyFrame_FastToLocalsWithError15597081
Ref: 513515597081
Ref: Legacy Local Variable APIs-Footnote-115597537
Node: Internal Frames15597579
Ref: c-api/frame internal-frames15597679
Ref: 513615597679
Ref: c-api/frame c _PyInterpreterFrame15597780
Ref: 513715597780
Ref: c-api/frame c PyUnstable_InterpreterFrame_GetCode15597908
Ref: 513815597908
Ref: c-api/frame c PyUnstable_InterpreterFrame_GetLasti15598329
Ref: 513915598329
Ref: c-api/frame c PyUnstable_InterpreterFrame_GetLine15598695
Ref: 513a15598695
Ref: Internal Frames-Footnote-115599120
Node: Generator Objects15599162
Ref: c-api/gen doc15599280
Ref: 513b15599280
Ref: c-api/gen gen-objects15599280
Ref: 513c15599280
Ref: c-api/gen generator-objects15599280
Ref: 513d15599280
Ref: c-api/gen translation-repo15599280
Ref: 513e15599280
Ref: c-api/gen c PyGenObject15599580
Ref: 514115599580
Ref: c-api/gen c PyGen_Type15599660
Ref: 514215599660
Ref: c-api/gen c PyGen_Check15599771
Ref: 514315599771
Ref: c-api/gen c PyGen_CheckExact15599933
Ref: 514415599933
Ref: c-api/gen c PyGen_New15600115
Ref: 513f15600115
Ref: c-api/gen c PyGen_NewWithQualName15600394
Ref: 514015600394
Ref: c-api/gen c PyGen_GetCode15600822
Ref: 514515600822
Node: Asynchronous Generator Objects15601075
Ref: c-api/gen asynchronous-generator-objects15601159
Ref: 514615601159
Ref: c-api/gen c PyAsyncGen_Type15601271
Ref: 514715601271
Ref: c-api/gen c PyAsyncGen_New15601518
Ref: 514815601518
Ref: c-api/gen c PyAsyncGen_CheckExact15602060
Ref: 514915602060
Ref: Asynchronous Generator Objects-Footnote-115602299
Node: Coroutine Objects<2>15602341
Ref: c-api/coro doc15602471
Ref: 514a15602471
Ref: c-api/coro coro-objects15602471
Ref: f0415602471
Ref: c-api/coro coroutine-objects15602471
Ref: 514b15602471
Ref: c-api/coro translation-repo15602471
Ref: 514c15602471
Ref: c-api/coro c PyCoroObject15602632
Ref: 514d15602632
Ref: c-api/coro c PyCoro_Type15602713
Ref: 514e15602713
Ref: c-api/coro c PyCoro_CheckExact15602825
Ref: 514f15602825
Ref: c-api/coro c PyCoro_New15603009
Ref: 515015603009
Node: Context Variables Objects15603426
Ref: c-api/contextvars doc15603563
Ref: 515115603563
Ref: c-api/contextvars context-variables-objects15603563
Ref: 515215603563
Ref: c-api/contextvars contextvarsobjects15603563
Ref: b1115603563
Ref: c-api/contextvars translation-repo15603563
Ref: 515315603563
Ref: c-api/contextvars contextvarsobjects-pointertype-change15603634
Ref: c4615603634
Ref: c-api/contextvars c PyContext15604175
Ref: 515415604175
Ref: c-api/contextvars c PyContextVar15604291
Ref: 515515604291
Ref: c-api/contextvars c PyContextToken15604413
Ref: 515615604413
Ref: c-api/contextvars c PyContext_Type15604532
Ref: 515715604532
Ref: c-api/contextvars c PyContextVar_Type15604644
Ref: 515815604644
Ref: c-api/contextvars c PyContextToken_Type15604768
Ref: 515915604768
Ref: c-api/contextvars c PyContext_CheckExact15604920
Ref: 515a15604920
Ref: c-api/contextvars c PyContextVar_CheckExact15605106
Ref: 515b15605106
Ref: c-api/contextvars c PyContextToken_CheckExact15605298
Ref: 515c15605298
Ref: c-api/contextvars c PyContext_New15605532
Ref: 515d15605532
Ref: c-api/contextvars c PyContext_Copy15605714
Ref: 515e15605714
Ref: c-api/contextvars c PyContext_CopyCurrent15605930
Ref: 515f15605930
Ref: c-api/contextvars c PyContext_Enter15606139
Ref: 516015606139
Ref: c-api/contextvars c PyContext_Exit15606312
Ref: 516115606312
Ref: c-api/contextvars c PyContextVar_New15606570
Ref: 516215606570
Ref: c-api/contextvars c PyContextVar_Get15606995
Ref: 516315606995
Ref: c-api/contextvars c PyContextVar_Set15607618
Ref: 516415607618
Ref: c-api/contextvars c PyContextVar_Reset15607907
Ref: 516515607907
Ref: Context Variables Objects-Footnote-115608243
Node: Objects for Type Hinting15608308
Ref: c-api/typehints doc15608416
Ref: 516615608416
Ref: c-api/typehints objects-for-type-hinting15608416
Ref: 516715608416
Ref: c-api/typehints translation-repo15608416
Ref: 516815608416
Ref: c-api/typehints typehintobjects15608416
Ref: 516915608416
Ref: c-api/typehints c Py_GenericAlias15608661
Ref: 4deb15608661
Ref: c-api/typehints c Py_GenericAliasType15610044
Ref: 4dec15610044
Node: C API for extension modules15610331
Ref: c-api/concrete c-api-for-extension-modules15610439
Ref: 516a15610439
Node: Curses C API15610629
Ref: c-api/curses doc15610727
Ref: 516b15610727
Ref: c-api/curses curses-c-api15610727
Ref: 516c15610727
Ref: c-api/curses c import_curses15611213
Ref: 516d15611213
Ref: c-api/curses c PyCurses_API15611685
Ref: 516e15611685
Ref: c-api/curses c PyCurses_API_pointers15612642
Ref: 517315612642
Ref: c-api/curses c PyCursesWindow_Type15612818
Ref: 516f15612818
Ref: c-api/curses c PyCursesWindow_Check15612961
Ref: 517415612961
Ref: c-api/curses c PyCursesSetupTermCalled15613292
Ref: 517015613292
Ref: c-api/curses c PyCursesInitialised15613699
Ref: 517115613699
Ref: c-api/curses c PyCursesInitialisedColor15614096
Ref: 517215614096
Node: Internal data15614515
Ref: c-api/curses internal-data15614641
Ref: 517515614641
Ref: c-api/curses c PyCurses_CAPSULE_NAME15614774
Ref: 517615614774
Node: DateTime Objects<2>15614959
Ref: c-api/datetime doc15615089
Ref: 517715615089
Ref: c-api/datetime datetime-objects15615089
Ref: 517815615089
Ref: c-api/datetime datetimeobjects15615089
Ref: 4f1e15615089
Ref: c-api/datetime translation-repo15615089
Ref: 517915615089
Ref: c-api/datetime c PyDateTime_IMPORT15615622
Ref: 517a15615622
Ref: c-api/datetime c PyDateTime_CAPI15616069
Ref: 517c15616069
Ref: c-api/datetime c PyDateTimeAPI15616307
Ref: 517b15616307
Ref: c-api/datetime c PyDateTime_Date15616523
Ref: 517d15616523
Ref: c-api/datetime c PyDateTime_DateTime15616638
Ref: 517e15616638
Ref: c-api/datetime c PyDateTime_Time15616761
Ref: 517f15616761
Ref: c-api/datetime c PyDateTime_Delta15616876
Ref: 518015616876
Ref: c-api/datetime c PyDateTime_DateType15617014
Ref: 518115617014
Ref: c-api/datetime c PyDateTime_DateTimeType15617239
Ref: 518215617239
Ref: c-api/datetime c PyDateTime_TimeType15617476
Ref: 518315617476
Ref: c-api/datetime c PyDateTime_DeltaType15617701
Ref: 518415617701
Ref: c-api/datetime c PyDateTime_TZInfoType15617974
Ref: 518515617974
Ref: c-api/datetime c PyDateTime_TimeZone_UTC15618253
Ref: be215618253
Ref: c-api/datetime c PyDate_Check15618478
Ref: 518615618478
Ref: c-api/datetime c PyDate_CheckExact15618712
Ref: 518715618712
Ref: c-api/datetime c PyDateTime_Check15618902
Ref: 518815618902
Ref: c-api/datetime c PyDateTime_CheckExact15619148
Ref: 518915619148
Ref: c-api/datetime c PyTime_Check15619346
Ref: 518a15619346
Ref: c-api/datetime c PyTime_CheckExact15619580
Ref: 518b15619580
Ref: c-api/datetime c PyDelta_Check15619770
Ref: 518c15619770
Ref: c-api/datetime c PyDelta_CheckExact15620006
Ref: 518d15620006
Ref: c-api/datetime c PyTZInfo_Check15620198
Ref: 518e15620198
Ref: c-api/datetime c PyTZInfo_CheckExact15620437
Ref: 518f15620437
Ref: c-api/datetime c PyDate_FromDate15620658
Ref: 519015620658
Ref: c-api/datetime c PyDateTime_FromDateAndTime15620878
Ref: 519115620878
Ref: c-api/datetime c PyDateTime_FromDateAndTimeAndFold15621210
Ref: 519215621210
Ref: c-api/datetime c PyTime_FromTime15621593
Ref: 519315621593
Ref: c-api/datetime c PyTime_FromTimeAndFold15621847
Ref: 519415621847
Ref: c-api/datetime c PyDelta_FromDSU15622157
Ref: 519515622157
Ref: c-api/datetime c PyTimeZone_FromOffset15622581
Ref: be015622581
Ref: c-api/datetime c PyTimeZone_FromOffsetAndName15622860
Ref: be115622860
Ref: c-api/datetime c PyDateTime_GET_YEAR15623419
Ref: 519615623419
Ref: c-api/datetime c PyDateTime_GET_MONTH15623523
Ref: 519715623523
Ref: c-api/datetime c PyDateTime_GET_DAY15623639
Ref: 519815623639
Ref: c-api/datetime c PyDateTime_DATE_GET_HOUR15623959
Ref: 519915623959
Ref: c-api/datetime c PyDateTime_DATE_GET_MINUTE15624082
Ref: 519a15624082
Ref: c-api/datetime c PyDateTime_DATE_GET_SECOND15624209
Ref: 519b15624209
Ref: c-api/datetime c PyDateTime_DATE_GET_MICROSECOND15624336
Ref: 519c15624336
Ref: c-api/datetime c PyDateTime_DATE_GET_FOLD15624487
Ref: 519d15624487
Ref: c-api/datetime c PyDateTime_DATE_GET_TZINFO15624637
Ref: 89c15624637
Ref: c-api/datetime c PyDateTime_TIME_GET_HOUR15625018
Ref: 519e15625018
Ref: c-api/datetime c PyDateTime_TIME_GET_MINUTE15625137
Ref: 519f15625137
Ref: c-api/datetime c PyDateTime_TIME_GET_SECOND15625260
Ref: 51a015625260
Ref: c-api/datetime c PyDateTime_TIME_GET_MICROSECOND15625383
Ref: 51a115625383
Ref: c-api/datetime c PyDateTime_TIME_GET_FOLD15625520
Ref: 51a215625520
Ref: c-api/datetime c PyDateTime_TIME_GET_TZINFO15625666
Ref: 89d15625666
Ref: c-api/datetime c PyDateTime_DELTA_GET_DAYS15626050
Ref: 51a315626050
Ref: c-api/datetime c PyDateTime_DELTA_GET_SECONDS15626220
Ref: 51a415626220
Ref: c-api/datetime c PyDateTime_DELTA_GET_MICROSECONDS15626388
Ref: 51a515626388
Ref: c-api/datetime c PyDateTime_FromTimestamp15626641
Ref: 51a615626641
Ref: c-api/datetime c PyDate_FromTimestamp15626934
Ref: 1b9f15626934
Node: Internal data<2>15627215
Ref: c-api/datetime internal-data15627323
Ref: 51a715627323
Ref: c-api/datetime c PyDateTime_CAPSULE_NAME15627456
Ref: 51a815627456
Node: Initialization Finalization and Threads15627649
Ref: c-api/init doc15627829
Ref: 51a915627829
Ref: c-api/init initialization15627829
Ref: 51aa15627829
Ref: c-api/init initialization-finalization-and-threads15627829
Ref: 51ab15627829
Ref: c-api/init translation-repo15627829
Ref: 51ac15627829
Node: Before Python Initialization15628515
Ref: c-api/init before-python-initialization15628658
Ref: 51ad15628658
Ref: c-api/init pre-init-safe15628658
Ref: be415628658
Node: Global configuration variables15631335
Ref: c-api/init global-conf-vars15631530
Ref: 51ae15631530
Ref: c-api/init global-configuration-variables15631530
Ref: 51b215631530
Ref: c-api/init c Py_BytesWarningFlag15631996
Ref: 3d715631996
Ref: c-api/init c Py_DebugFlag15632522
Ref: 3c915632522
Ref: c-api/init c Py_DontWriteBytecodeFlag15633001
Ref: 3dd15633001
Ref: c-api/init c Py_FrozenFlag15633519
Ref: 3d915633519
Ref: c-api/init c Py_HashRandomizationFlag15633992
Ref: 3e315633992
Ref: c-api/init c Py_IgnoreEnvironmentFlag15634570
Ref: 3db15634570
Ref: c-api/init c Py_InspectFlag15635063
Ref: 3d115635063
Ref: c-api/init c Py_InteractiveFlag15635678
Ref: 3cf15635678
Ref: c-api/init c Py_IsolatedFlag15636007
Ref: 3e615636007
Ref: c-api/init c Py_LegacyWindowsFSEncodingFlag15636525
Ref: 3e815636525
Ref: c-api/init c Py_LegacyWindowsStdioFlag15637286
Ref: 3ea15637286
Ref: c-api/init c Py_NoSiteFlag15637930
Ref: 3d515637930
Ref: c-api/init c Py_NoUserSiteDirectory15638550
Ref: 3df15638550
Ref: c-api/init c Py_OptimizeFlag15639069
Ref: 3d315639069
Ref: c-api/init c Py_QuietFlag15639463
Ref: 3cd15639463
Ref: c-api/init c Py_UnbufferedStdioFlag15639896
Ref: 3e115639896
Ref: c-api/init c Py_VerboseFlag15640356
Ref: 3cb15640356
Ref: Global configuration variables-Footnote-115641090
Ref: Global configuration variables-Footnote-215641132
Node: Initializing and finalizing the interpreter15641174
Ref: c-api/init initializing-and-finalizing-the-interpreter15641364
Ref: 51b315641364
Ref: c-api/init c Py_Initialize15641465
Ref: 8b415641465
Ref: c-api/init c Py_InitializeEx15642624
Ref: 4df315642624
Ref: c-api/init c Py_InitializeFromConfig15643100
Ref: 3c815643100
Ref: c-api/init c Py_IsInitialized15643539
Ref: 4c1315643539
Ref: c-api/init c Py_IsFinalizing15643847
Ref: 35b15643847
Ref: c-api/init c Py_FinalizeEx15644105
Ref: d3d15644105
Ref: c-api/init c Py_Finalize15646902
Ref: 13a615646902
Ref: c-api/init c Py_BytesMain15647097
Ref: 9cc15647097
Ref: c-api/init c Py_Main15647427
Ref: c4515647427
Ref: c-api/init c Py_RunMain15649785
Ref: 9d015649785
Ref: c-api/init c PyUnstable_AtExit15651358
Ref: 169115651358
Node: Process-wide parameters15651923
Ref: c-api/init process-wide-parameters15652127
Ref: 51b915652127
Ref: c-api/init c Py_SetProgramName15652188
Ref: 174915652188
Ref: c-api/init c Py_GetProgramName15653355
Ref: 3bc15653355
Ref: c-api/init c Py_GetPrefix15653969
Ref: 3b815653969
Ref: c-api/init c Py_GetExecPrefix15655217
Ref: 3b415655217
Ref: c-api/init c Py_GetProgramFullPath15657872
Ref: 3ba15657872
Ref: c-api/init c Py_GetPath15658684
Ref: 3b615658684
Ref: c-api/init c Py_GetVersion15659760
Ref: 4df115659760
Ref: c-api/init c Py_GetPlatform15660406
Ref: 4def15660406
Ref: c-api/init c Py_GetCopyright15661039
Ref: 4dee15661039
Ref: c-api/init c Py_GetCompiler15661460
Ref: 4ded15661460
Ref: c-api/init c Py_GetBuildInfo15661886
Ref: 148015661886
Ref: c-api/init c PySys_SetArgvEx15662339
Ref: 174a15662339
Ref: c-api/init c PySys_SetArgv15664777
Ref: 174b15664777
Ref: c-api/init c Py_SetPythonHome15665629
Ref: 174815665629
Ref: c-api/init c Py_GetPythonHome15666468
Ref: 3bd15666468
Ref: Process-wide parameters-Footnote-115667152
Node: Thread State and the Global Interpreter Lock15667207
Ref: c-api/init thread-state-and-the-global-interpreter-lock15667391
Ref: 51ba15667391
Ref: c-api/init threads15667391
Ref: 51bb15667391
Node: Releasing the GIL from extension code15668969
Ref: c-api/init releasing-the-gil-from-extension-code15669122
Ref: 51bc15669122
Node: Non-Python created threads15670997
Ref: c-api/init gilstate15671178
Ref: 51bd15671178
Ref: c-api/init non-python-created-threads15671178
Ref: 51be15671178
Node: Cautions about fork15672931
Ref: c-api/init cautions-about-fork15673114
Ref: 51bf15673114
Ref: c-api/init fork-and-threads15673114
Ref: 4ed115673114
Node: Cautions regarding runtime finalization15675046
Ref: c-api/init cautions-regarding-runtime-finalization15675217
Ref: 51c015675217
Ref: c-api/init id115675217
Ref: 51c115675217
Node: High-level API15676945
Ref: c-api/init high-level-api15677110
Ref: 51c215677110
Ref: c-api/init c PyInterpreterState15677284
Ref: 8c515677284
Ref: c-api/init c PyThreadState15678087
Ref: 79015678087
Ref: c-api/init c PyThreadState interp15678291
Ref: 51c415678291
Ref: c-api/init c PyEval_InitThreads15678396
Ref: 174c15678396
Ref: c-api/init c PyEval_SaveThread15678972
Ref: 3ab15678972
Ref: c-api/init c PyEval_RestoreThread15679340
Ref: 3ac15679340
Ref: c-api/init c PyThreadState_Get15680140
Ref: 37515680140
Ref: c-api/init c PyThreadState_GetUnchecked15680521
Ref: 37415680521
Ref: c-api/init c PyThreadState_Swap15680907
Ref: 4d8c15680907
Ref: c-api/init c PyGILState_STATE15681384
Ref: 4cf015681384
Ref: c-api/init c PyGILState_STATE PyGILState_LOCKED15681586
Ref: 51c515681586
Ref: c-api/init c PyGILState_STATE PyGILState_UNLOCKED15681734
Ref: 51c615681734
Ref: c-api/init c PyGILState_Ensure15681880
Ref: 3ae15681880
Ref: c-api/init c PyGILState_Release15683674
Ref: 3af15683674
Ref: c-api/init c PyGILState_GetThisThreadState15684199
Ref: 4cef15684199
Ref: c-api/init c PyGILState_Check15684653
Ref: 51c715684653
Ref: c-api/init c Py_BEGIN_ALLOW_THREADS15685388
Ref: 4b8815685388
Ref: c-api/init c Py_END_ALLOW_THREADS15685737
Ref: a9d15685737
Ref: c-api/init c Py_BLOCK_THREADS15686063
Ref: 4de915686063
Ref: c-api/init c Py_UNBLOCK_THREADS15686286
Ref: 4e0815686286
Ref: High-level API-Footnote-115686580
Node: Low-level API15686622
Ref: c-api/init low-level-api15686739
Ref: 51c815686739
Ref: c-api/init c PyInterpreterState_New15686954
Ref: 442215686954
Ref: c-api/init c PyInterpreterState_Clear15687356
Ref: 442115687356
Ref: c-api/init c PyInterpreterState_Delete15687700
Ref: 4cfd15687700
Ref: c-api/init c PyThreadState_New15688038
Ref: 4d8b15688038
Ref: c-api/init c PyThreadState_Clear15688393
Ref: 172915688393
Ref: c-api/init c PyThreadState_Delete15688865
Ref: 1b3215688865
Ref: c-api/init c PyThreadState_DeleteCurrent15689167
Ref: 1b6315689167
Ref: c-api/init c PyThreadState_GetFrame15689501
Ref: 79115689501
Ref: c-api/init c PyThreadState_GetID15689947
Ref: 97c15689947
Ref: c-api/init c PyThreadState_GetInterpreter15690229
Ref: 97b15690229
Ref: c-api/init c PyThreadState_EnterTracing15690534
Ref: 75715690534
Ref: c-api/init c PyThreadState_LeaveTracing15690793
Ref: 75815690793
Ref: c-api/init c PyInterpreterState_Get15691137
Ref: 3b015691137
Ref: c-api/init c PyInterpreterState_GetID15691512
Ref: be515691512
Ref: c-api/init c PyInterpreterState_GetDict15691858
Ref: 4cfe15691858
Ref: c-api/init c PyUnstable_InterpreterState_GetMainModule15692587
Ref: 51c915692587
Ref: c-api/init c _PyFrameEvalFunction15693074
Ref: 77915693074
Ref: c-api/init c _PyInterpreterState_GetEvalFrameFunc15693629
Ref: 1b2015693629
Ref: c-api/init c _PyInterpreterState_SetEvalFrameFunc15693907
Ref: 1b2115693907
Ref: c-api/init c PyThreadState_GetDict15694180
Ref: 4d8a15694180
Ref: c-api/init c PyThreadState_SetAsyncExc15694731
Ref: be315694731
Ref: c-api/init c PyEval_AcquireThread15695552
Ref: 3ad15695552
Ref: c-api/init c PyEval_ReleaseThread15696729
Ref: 4ca015696729
Ref: Low-level API-Footnote-115697377
Ref: Low-level API-Footnote-215697419
Node: Sub-interpreter support15697461
Ref: c-api/init id215697648
Ref: 51ca15697648
Ref: c-api/init sub-interpreter-support15697648
Ref: 58a15697648
Ref: c-api/init c PyInterpreterConfig15698579
Ref: 57015698579
Ref: c-api/init c PyInterpreterConfig use_main_obmalloc15698866
Ref: 45de15698866
Ref: c-api/init c PyInterpreterConfig allow_fork15699308
Ref: 51cf15699308
Ref: c-api/init c PyInterpreterConfig allow_exec15699642
Ref: 51d015699642
Ref: c-api/init c PyInterpreterConfig allow_threads15700036
Ref: 51d115700036
Ref: c-api/init c PyInterpreterConfig allow_daemon_threads15700227
Ref: 51d215700227
Ref: c-api/init c PyInterpreterConfig check_multi_interp_extensions15700511
Ref: 51cc15700511
Ref: c-api/init c PyInterpreterConfig gil15701034
Ref: 51cd15701034
Ref: c-api/init c PyInterpreterConfig_DEFAULT_GIL15701182
Ref: 51d315701182
Ref: c-api/init c PyInterpreterConfig_SHARED_GIL15701342
Ref: 51d415701342
Ref: c-api/init c PyInterpreterConfig_OWN_GIL15701455
Ref: 51ce15701455
Ref: c-api/init c Py_NewInterpreterFromConfig15701706
Ref: 45f15701706
Ref: c-api/init c Py_NewInterpreter15706208
Ref: 18d415706208
Ref: c-api/init c Py_EndInterpreter15706684
Ref: 19a015706684
Ref: Sub-interpreter support-Footnote-115707486
Node: A Per-Interpreter GIL15707528
Ref: c-api/init a-per-interpreter-gil15707634
Ref: 51d615707634
Ref: c-api/init per-interpreter-gil15707634
Ref: 51c315707634
Ref: A Per-Interpreter GIL-Footnote-115709695
Ref: A Per-Interpreter GIL-Footnote-215709737
Node: Bugs and caveats15709779
Ref: c-api/init bugs-and-caveats15709885
Ref: 51d515709885
Node: Asynchronous Notifications15711491
Ref: c-api/init asynchronous-notifications15711655
Ref: 51d715711655
Ref: c-api/init c Py_AddPendingCall15711900
Ref: 98b15711900
Ref: c-api/init c Py_MakePendingCalls15714176
Ref: 4df415714176
Node: Profiling and Tracing15714766
Ref: c-api/init profiling15714924
Ref: 51d815714924
Ref: c-api/init profiling-and-tracing15714924
Ref: 51d915714924
Ref: c-api/init c Py_tracefunc15715603
Ref: 51da15715603
Ref: c-api/init c PyTrace_CALL15717952
Ref: 51db15717952
Ref: c-api/init c PyTrace_EXCEPTION15718342
Ref: 51dc15718342
Ref: c-api/init c PyTrace_LINE15718951
Ref: 51dd15718951
Ref: c-api/init c PyTrace_RETURN15719253
Ref: 51de15719253
Ref: c-api/init c PyTrace_C_CALL15719406
Ref: 51df15719406
Ref: c-api/init c PyTrace_C_EXCEPTION15719568
Ref: 51e015719568
Ref: c-api/init c PyTrace_C_RETURN15719737
Ref: 51e115719737
Ref: c-api/init c PyTrace_OPCODE15719892
Ref: 51e215719892
Ref: c-api/init c PyEval_SetProfile15720232
Ref: 154c15720232
Ref: c-api/init c PyEval_SetProfileAllThreads15720922
Ref: 56215720922
Ref: c-api/init c PyEval_SetTrace15721434
Ref: 42415721434
Ref: c-api/init c PyEval_SetTraceAllThreads15722114
Ref: 42515722114
Node: Reference tracing15722611
Ref: c-api/init reference-tracing15722768
Ref: 51e315722768
Ref: c-api/init c PyRefTracer15722841
Ref: 51e415722841
Ref: c-api/init c PyRefTracer_CREATE15723397
Ref: 51e515723397
Ref: c-api/init c PyRefTracer_DESTROY15723561
Ref: 51e615723561
Ref: c-api/init c PyRefTracer_SetTracer15723728
Ref: 36f15723728
Ref: c-api/init c PyRefTracer_GetTracer15724523
Ref: 37015724523
Node: Advanced Debugger Support15724976
Ref: c-api/init advanced-debugger-support15725140
Ref: 51e715725140
Ref: c-api/init advanced-debugging15725140
Ref: 51e815725140
Ref: c-api/init c PyInterpreterState_Head15725282
Ref: 154f15725282
Ref: c-api/init c PyInterpreterState_Main15725460
Ref: 51cb15725460
Ref: c-api/init c PyInterpreterState_Next15725594
Ref: 155015725594
Ref: c-api/init c PyInterpreterState_ThreadHead15725808
Ref: 155115725808
Ref: c-api/init c PyThreadState_Next15726062
Ref: 155215726062
Node: Thread Local Storage Support15726321
Ref: c-api/init thread-local-storage15726497
Ref: 51e915726497
Ref: c-api/init thread-local-storage-support15726497
Ref: 51ea15726497
Node: Thread Specific Storage TSS API15727606
Ref: c-api/init thread-specific-storage-api15727739
Ref: af415727739
Ref: c-api/init thread-specific-storage-tss-api15727739
Ref: 51eb15727739
Ref: c-api/init c Py_tss_t15728125
Ref: af515728125
Ref: c-api/init c Py_tss_NEEDS_INIT15728569
Ref: 51ec15728569
Ref: Thread Specific Storage TSS API-Footnote-115728856
Node: Dynamic Allocation15728898
Ref: c-api/init dynamic-allocation15729003
Ref: 51ed15729003
Ref: c-api/init c PyThread_tss_alloc15729283
Ref: 40815729283
Ref: c-api/init c PyThread_tss_free15729577
Ref: 40a15729577
Node: Methods<2>15730060
Ref: c-api/init methods15730165
Ref: 51ee15730165
Ref: c-api/init c PyThread_tss_is_created15730469
Ref: 4d9915730469
Ref: c-api/init c PyThread_tss_create15730720
Ref: 4d9815730720
Ref: c-api/init c PyThread_tss_delete15731199
Ref: 41015731199
Ref: c-api/init c PyThread_tss_set15731693
Ref: 40c15731693
Ref: c-api/init c PyThread_tss_get15732012
Ref: 40e15732012
Node: Thread Local Storage TLS API15732304
Ref: c-api/init thread-local-storage-api15732437
Ref: af315732437
Ref: c-api/init thread-local-storage-tls-api15732437
Ref: 51ef15732437
Ref: c-api/init c PyThread_create_key15733060
Ref: 40715733060
Ref: c-api/init c PyThread_delete_key15733147
Ref: 40915733147
Ref: c-api/init c PyThread_set_key_value15733242
Ref: 40b15733242
Ref: c-api/init c PyThread_get_key_value15733352
Ref: 40d15733352
Ref: c-api/init c PyThread_delete_key_value15733451
Ref: 40f15733451
Ref: c-api/init c PyThread_ReInitTLS15733552
Ref: 41115733552
Node: Synchronization Primitives<2>15733639
Ref: c-api/init synchronization-primitives15733818
Ref: 51f015733818
Ref: c-api/init c PyMutex15733938
Ref: 15b15733938
Ref: c-api/init c PyMutex_Lock15734560
Ref: 32b15734560
Ref: c-api/init c PyMutex_Unlock15734862
Ref: 32c15734862
Node: Python Critical Section API15735116
Ref: c-api/init id315735237
Ref: 51f115735237
Ref: c-api/init python-critical-section-api15735237
Ref: 51f215735237
Ref: c-api/init c Py_BEGIN_CRITICAL_SECTION15737731
Ref: 505015737731
Ref: c-api/init c Py_END_CRITICAL_SECTION15738129
Ref: 51f415738129
Ref: c-api/init c Py_BEGIN_CRITICAL_SECTION215738440
Ref: 51f315738440
Ref: c-api/init c Py_END_CRITICAL_SECTION215738978
Ref: 51f515738978
Node: Legacy Locking APIs15739293
Ref: c-api/init legacy-locking-apis15739414
Ref: 51f615739414
Ref: c-api/init c PyThread_type_lock15739645
Ref: 51f715739645
Ref: c-api/init c PyLockStatus15739726
Ref: 51f815739726
Ref: c-api/init c PY_LOCK_FAILURE15739810
Ref: 51f915739810
Ref: c-api/init c PY_LOCK_ACQUIRED15739900
Ref: 51fa15739900
Ref: c-api/init c PY_LOCK_INTR15739999
Ref: 51fb15739999
Ref: c-api/init c PyThread_allocate_lock15740096
Ref: 4d9015740096
Ref: c-api/init c PyThread_free_lock15740597
Ref: 4d9215740597
Ref: c-api/init c PyThread_acquire_lock_timed15740850
Ref: 4d8f15740850
Ref: c-api/init c PyThread_acquire_lock15741825
Ref: 4d8e15741825
Ref: c-api/init c PyThread_release_lock15742563
Ref: 4d9615742563
Node: Operating System Thread APIs15742821
Ref: c-api/init operating-system-thread-apis15742963
Ref: 51fc15742963
Ref: c-api/init c PYTHREAD_INVALID_THREAD_ID15743036
Ref: 51fd15743036
Ref: c-api/init c PyThread_start_new_thread15743187
Ref: 1bdc15743187
Ref: c-api/init c PyThread_get_thread_ident15743721
Ref: 4d9415743721
Ref: c-api/init c PyThread_GetInfo15744070
Ref: 4d8d15744070
Ref: c-api/init c PY_HAVE_THREAD_NATIVE_ID15744598
Ref: 51fe15744598
Ref: c-api/init c PyThread_get_thread_native_id15744709
Ref: 194815744709
Ref: c-api/init c PyThread_exit_thread15745278
Ref: 4d9115745278
Ref: c-api/init c PyThread_init_thread15746263
Ref: 4d9515746263
Ref: c-api/init c PyThread_set_stacksize15746507
Ref: 4d9715746507
Ref: c-api/init c PyThread_get_stacksize15746928
Ref: 4d9315746928
Ref: Operating System Thread APIs-Footnote-115747244
Node: Python Initialization Configuration15747296
Ref: c-api/init_config doc15747471
Ref: 51ff15747471
Ref: c-api/init_config init-config15747471
Ref: 3aa15747471
Ref: c-api/init_config python-initialization-configuration15747471
Ref: 520015747471
Ref: c-api/init_config translation-repo15747471
Ref: 520115747471
Ref: Python Initialization Configuration-Footnote-115748941
Node: Example<17>15748983
Ref: c-api/init_config example15749091
Ref: 520315749091
Node: PyWideStringList15750100
Ref: c-api/init_config pywidestringlist15750225
Ref: 520415750225
Ref: c-api/init_config c PyWideStringList15750274
Ref: 9b915750274
Ref: c-api/init_config c PyWideStringList_Append15750469
Ref: 9ca15750469
Ref: c-api/init_config c PyWideStringList_Insert15750697
Ref: 9cb15750697
Ref: c-api/init_config c PyWideStringList length15751156
Ref: 520515751156
Ref: c-api/init_config c PyWideStringList items15751230
Ref: 520615751230
Node: PyStatus15751289
Ref: c-api/init_config pystatus15751414
Ref: 520715751414
Ref: c-api/init_config c PyStatus15751447
Ref: 9b815751447
Ref: c-api/init_config c PyStatus exitcode15751670
Ref: 520815751670
Ref: c-api/init_config c PyStatus err_msg15751759
Ref: 520915751759
Ref: c-api/init_config c PyStatus func15751825
Ref: 520a15751825
Ref: c-api/init_config c PyStatus_Ok15751973
Ref: 9c915751973
Ref: c-api/init_config c PyStatus_Error15752055
Ref: 9c315752055
Ref: c-api/init_config c PyStatus_NoMemory15752243
Ref: 9c815752243
Ref: c-api/init_config c PyStatus_Exit15752365
Ref: 9c515752365
Ref: c-api/init_config c PyStatus_Exception15752526
Ref: 9c415752526
Ref: c-api/init_config c PyStatus_IsError15752757
Ref: 9c615752757
Ref: c-api/init_config c PyStatus_IsExit15752853
Ref: 9c715752853
Ref: c-api/init_config c Py_ExitStatusException15752947
Ref: 9cd15752947
Node: PyPreConfig15753888
Ref: c-api/init_config pypreconfig15754034
Ref: 520b15754034
Ref: c-api/init_config c PyPreConfig15754073
Ref: 9b715754073
Ref: c-api/init_config c PyPreConfig_InitPythonConfig15754198
Ref: 9c215754198
Ref: c-api/init_config c PyPreConfig_InitIsolatedConfig15754386
Ref: 9c115754386
Ref: c-api/init_config c PyPreConfig allocator15754602
Ref: 520c15754602
Ref: c-api/init_config c PyPreConfig configure_locale15756389
Ref: 520e15756389
Ref: c-api/init_config c PyPreConfig coerce_c_locale15756750
Ref: 520f15756750
Ref: c-api/init_config c PyPreConfig coerce_c_locale_warn15757069
Ref: 521015757069
Ref: c-api/init_config c PyPreConfig dev_mode15757256
Ref: 521115757256
Ref: c-api/init_config c PyPreConfig isolated15757453
Ref: 521315757453
Ref: c-api/init_config c PyPreConfig legacy_windows_fs_encoding15757616
Ref: 3e915757616
Ref: c-api/init_config c PyPreConfig parse_argv15758188
Ref: 521415758188
Ref: c-api/init_config c PyPreConfig use_environment15758573
Ref: 521515758573
Ref: c-api/init_config c PyPreConfig utf8_mode15758792
Ref: 3ed15758792
Node: Preinitialize Python with PyPreConfig15759203
Ref: c-api/init_config c-preinit15759349
Ref: 3fa215759349
Ref: c-api/init_config preinitialize-python-with-pypreconfig15759349
Ref: 521615759349
Ref: c-api/init_config c Py_PreInitialize15759838
Ref: 3ee15759838
Ref: c-api/init_config c Py_PreInitializeFromBytesArgs15760038
Ref: 9cf15760038
Ref: c-api/init_config c Py_PreInitializeFromArgs15760398
Ref: 9ce15760398
Node: PyConfig15762329
Ref: c-api/init_config pyconfig15762492
Ref: 521715762492
Ref: c-api/init_config c PyConfig15762525
Ref: 3a915762525
Ref: c-api/init_config c PyConfig_InitPythonConfig15762755
Ref: 9bc15762755
Ref: c-api/init_config c PyConfig_InitIsolatedConfig15762916
Ref: 9bb15762916
Ref: c-api/init_config c PyConfig_SetString15763081
Ref: 9c015763081
Ref: c-api/init_config c PyConfig_SetBytesString15763353
Ref: 9bf15763353
Ref: c-api/init_config c PyConfig_SetArgv15763683
Ref: 9bd15763683
Ref: c-api/init_config c PyConfig_SetBytesArgv15763999
Ref: 9be15763999
Ref: c-api/init_config c PyConfig_SetWideStringList15764368
Ref: 1b7515764368
Ref: c-api/init_config c PyConfig_Read15764675
Ref: 79315764675
Ref: c-api/init_config c PyConfig_Clear15766013
Ref: 9ba15766013
Ref: c-api/init_config c PyConfig argv15767120
Ref: 3c615767120
Ref: c-api/init_config c PyConfig safe_path15768113
Ref: 77615768113
Ref: c-api/init_config c PyConfig base_exec_prefix15768991
Ref: 521815768991
Ref: c-api/init_config c PyConfig base_executable15769236
Ref: 521a15769236
Ref: c-api/init_config c PyConfig base_prefix15769634
Ref: 521b15769634
Ref: c-api/init_config c PyConfig buffered_stdio15769864
Ref: 3e215769864
Ref: c-api/init_config c PyConfig bytes_warning15770277
Ref: 3d815770277
Ref: c-api/init_config c PyConfig warn_default_encoding15770716
Ref: 521e15770716
Ref: c-api/init_config c PyConfig code_debug_ranges15771028
Ref: 521f15771028
Ref: c-api/init_config c PyConfig check_hash_pycs_mode15771501
Ref: 522015771501
Ref: c-api/init_config c PyConfig configure_c_stdio15772173
Ref: 521d15772173
Ref: c-api/init_config c PyConfig dev_mode15772722
Ref: 521215772722
Ref: c-api/init_config c PyConfig dump_refs15773022
Ref: 522115773022
Ref: c-api/init_config c PyConfig exec_prefix15773435
Ref: 521915773435
Ref: c-api/init_config c PyConfig executable15773787
Ref: 3a815773787
Ref: c-api/init_config c PyConfig faulthandler15774105
Ref: 522215774105
Ref: c-api/init_config c PyConfig filesystem_encoding15774459
Ref: 3eb15774459
Ref: c-api/init_config c PyConfig filesystem_errors15775686
Ref: 3ec15775686
Ref: c-api/init_config c PyConfig hash_seed15776355
Ref: 3e515776355
Ref: c-api/init_config c PyConfig use_hash_seed15776399
Ref: 3e415776399
Ref: c-api/init_config c PyConfig home15776806
Ref: 3be15776806
Ref: c-api/init_config c PyConfig import_time15777158
Ref: 522315777158
Ref: c-api/init_config c PyConfig inspect15777411
Ref: 3d215777411
Ref: c-api/init_config c PyConfig install_signal_handlers15777999
Ref: 8c615777999
Ref: c-api/init_config c PyConfig interactive15778160
Ref: 3d015778160
Ref: c-api/init_config c PyConfig int_max_str_digits15778364
Ref: 522415778364
Ref: c-api/init_config c PyConfig cpu_count15779253
Ref: 522515779253
Ref: c-api/init_config c PyConfig isolated15779740
Ref: 3e715779740
Ref: c-api/init_config c PyConfig legacy_windows_stdio15780741
Ref: 3a715780741
Ref: c-api/init_config c PyConfig malloc_stats15781338
Ref: 522615781338
Ref: c-api/init_config c PyConfig platlibdir15781722
Ref: 1ac815781722
Ref: c-api/init_config c PyConfig pythonpath_env15782533
Ref: 522715782533
Ref: c-api/init_config c PyConfig module_search_paths15782873
Ref: 3a515782873
Ref: c-api/init_config c PyConfig module_search_paths_set15782942
Ref: 5f215782942
Ref: c-api/init_config c PyConfig optimization_level15783461
Ref: 3d415783461
Ref: c-api/init_config c PyConfig orig_argv15783956
Ref: 89b15783956
Ref: c-api/init_config c PyConfig parse_argv15784600
Ref: 1a9815784600
Ref: c-api/init_config c PyConfig parser_debug15785479
Ref: 3ca15785479
Ref: c-api/init_config c PyConfig pathconfig_warnings15785955
Ref: 3da15785955
Ref: c-api/init_config c PyConfig prefix15786374
Ref: 521c15786374
Ref: c-api/init_config c PyConfig program_name15786703
Ref: 3c715786703
Ref: c-api/init_config c PyConfig pycache_prefix15787435
Ref: 522815787435
Ref: c-api/init_config c PyConfig quiet15787897
Ref: 3ce15787897
Ref: c-api/init_config c PyConfig run_command15788163
Ref: 51b515788163
Ref: c-api/init_config c PyConfig run_filename15788340
Ref: 51b615788340
Ref: c-api/init_config c PyConfig run_module15788807
Ref: 51b715788807
Ref: c-api/init_config c PyConfig run_presite15788983
Ref: 522a15788983
Ref: c-api/init_config c PyConfig show_ref_count15789474
Ref: 522b15789474
Ref: c-api/init_config c PyConfig site_import15789830
Ref: 3d615789830
Ref: c-api/init_config c PyConfig skip_source_first_line15790483
Ref: 522915790483
Ref: c-api/init_config c PyConfig stdio_encoding15790856
Ref: 3a615790856
Ref: c-api/init_config c PyConfig stdio_errors15790900
Ref: 45ed15790900
Ref: c-api/init_config c PyConfig tracemalloc15791792
Ref: 522c15791792
Ref: c-api/init_config c PyConfig perf_profiling15792145
Ref: 522d15792145
Ref: c-api/init_config c PyConfig use_environment15792829
Ref: 3dc15792829
Ref: c-api/init_config c PyConfig user_site_directory15793151
Ref: 3e015793151
Ref: c-api/init_config c PyConfig verbose15793546
Ref: 3cc15793546
Ref: c-api/init_config c PyConfig warnoptions15794154
Ref: 3a315794154
Ref: c-api/init_config c PyConfig write_bytecode15794996
Ref: 3de15794996
Ref: c-api/init_config c PyConfig xoptions15795455
Ref: 3a415795455
Ref: PyConfig-Footnote-115796072
Ref: PyConfig-Footnote-215796114
Node: Initialization with PyConfig15796156
Ref: c-api/init_config init-from-config15796304
Ref: 51b415796304
Ref: c-api/init_config initialization-with-pyconfig15796304
Ref: 522e15796304
Node: Isolated Configuration15799985
Ref: c-api/init_config init-isolated-conf15800145
Ref: 520215800145
Ref: c-api/init_config isolated-configuration15800145
Ref: 522f15800145
Node: Python Configuration15800912
Ref: c-api/init_config init-python-config15801069
Ref: 51b815801069
Ref: c-api/init_config python-configuration15801069
Ref: 523015801069
Ref: Python Configuration-Footnote-115801701
Ref: Python Configuration-Footnote-215801743
Node: Python Path Configuration15801785
Ref: c-api/init_config init-path-config15801934
Ref: 8b515801934
Ref: c-api/init_config python-path-configuration15801934
Ref: 523115801934
Node: Py_GetArgcArgv15805647
Ref: c-api/init_config py-getargcargv15805826
Ref: 523215805826
Ref: c-api/init_config c Py_GetArgcArgv15805877
Ref: 1ae815805877
Node: Multi-Phase Initialization Private Provisional API15806078
Ref: c-api/init_config multi-phase-initialization-private-provisional-api15806223
Ref: 523315806223
Ref: c-api/init_config c _Py_InitializeMain15807420
Ref: 523415807420
Ref: Multi-Phase Initialization Private Provisional API-Footnote-115809447
Ref: Multi-Phase Initialization Private Provisional API-Footnote-215809489
Node: Memory Management15809531
Ref: c-api/memory doc15809696
Ref: 523515809696
Ref: c-api/memory memory15809696
Ref: 520d15809696
Ref: c-api/memory memory-management15809696
Ref: 523615809696
Ref: c-api/memory translation-repo15809696
Ref: 523715809696
Node: Overview<4>15810080
Ref: c-api/memory memoryoverview15810171
Ref: 523815810171
Ref: c-api/memory overview15810171
Ref: 523915810171
Node: Allocator Domains15814087
Ref: c-api/memory allocator-domains15814207
Ref: 523a15814207
Ref: c-api/memory id115814258
Ref: 523b15814258
Node: Raw Memory Interface15816273
Ref: c-api/memory raw-memory-interface15816398
Ref: 524115816398
Ref: c-api/memory raw-memoryinterface15816398
Ref: 523d15816398
Ref: c-api/memory c PyMem_RawMalloc15816841
Ref: 39315816841
Ref: c-api/memory c PyMem_RawCalloc15817285
Ref: 39415817285
Ref: c-api/memory c PyMem_RawRealloc15817844
Ref: 39515817844
Ref: c-api/memory c PyMem_RawFree15818651
Ref: 39615818651
Node: Memory Interface15819120
Ref: c-api/memory memory-interface15819245
Ref: 524215819245
Ref: c-api/memory memoryinterface15819245
Ref: 523e15819245
Ref: c-api/memory c PyMem_Malloc15819751
Ref: c8715819751
Ref: c-api/memory c PyMem_Calloc15820170
Ref: ee115820170
Ref: c-api/memory c PyMem_Realloc15820723
Ref: 106f15820723
Ref: c-api/memory c PyMem_Free15821494
Ref: 149115821494
Ref: c-api/memory c PyMem_New15822031
Ref: 157415822031
Ref: c-api/memory c PyMem_Resize15822266
Ref: 524315822266
Ref: c-api/memory c PyMem_Del15822714
Ref: 157515822714
Node: Deprecated aliases<2>15822851
Ref: c-api/memory deprecated-aliases15822925
Ref: 524415822925
Ref: c-api/memory c PyMem_MALLOC15823453
Ref: 524515823453
Ref: c-api/memory c PyMem_NEW15823650
Ref: 524615823650
Ref: c-api/memory c PyMem_REALLOC15823843
Ref: 524715823843
Ref: c-api/memory c PyMem_RESIZE15824044
Ref: 524815824044
Ref: c-api/memory c PyMem_FREE15824223
Ref: 524915824223
Ref: c-api/memory c PyMem_DEL15824415
Ref: 524a15824415
Node: Object allocators15824781
Ref: c-api/memory object-allocators15824911
Ref: 524b15824911
Ref: c-api/memory objectinterface15824911
Ref: 523f15824911
Ref: c-api/memory c PyObject_Malloc15825600
Ref: c8915825600
Ref: c-api/memory c PyObject_Calloc15826025
Ref: ee215826025
Ref: c-api/memory c PyObject_Realloc15826584
Ref: 149215826584
Ref: c-api/memory c PyObject_Free15827373
Ref: c8615827373
Node: Default Memory Allocators15827819
Ref: c-api/memory default-memory-allocators15827960
Ref: 1ef315827960
Ref: c-api/memory id215827960
Ref: 524d15827960
Node: Customize Memory Allocators15830460
Ref: c-api/memory customize-memory-allocators15830627
Ref: 524c15830627
Ref: c-api/memory id315830627
Ref: 524e15830627
Ref: c-api/memory c PyMemAllocatorEx15830721
Ref: f0215830721
Ref: c-api/memory c PyMemAllocatorDomain15832555
Ref: 523c15832555
Ref: c-api/memory c PYMEM_DOMAIN_RAW15832653
Ref: 1ef415832653
Ref: c-api/memory c PYMEM_DOMAIN_MEM15832894
Ref: c8a15832894
Ref: c-api/memory c PYMEM_DOMAIN_OBJ15833125
Ref: c8815833125
Ref: c-api/memory c PyMem_GetAllocator15833367
Ref: 51b015833367
Ref: c-api/memory c PyMem_SetAllocator15833539
Ref: 58e15833539
Ref: c-api/memory c PyMem_SetupDebugHooks15835467
Ref: c8b15835467
Node: Debug hooks on the Python memory allocators15835617
Ref: c-api/memory debug-hooks-on-the-python-memory-allocators15835781
Ref: 524f15835781
Ref: c-api/memory pymem-debug-hooks15835781
Ref: 1ef615835781
Node: The pymalloc allocator15841024
Ref: c-api/memory pymalloc15841183
Ref: d3715841183
Ref: c-api/memory the-pymalloc-allocator15841183
Ref: 525015841183
Node: Customize pymalloc Arena Allocator15842498
Ref: c-api/memory customize-pymalloc-arena-allocator15842591
Ref: 525115842591
Ref: c-api/memory c PyObjectArenaAllocator15842703
Ref: 525215842703
Ref: c-api/memory c PyObject_GetArenaAllocator15843712
Ref: 51b115843712
Ref: c-api/memory c PyObject_SetArenaAllocator15843838
Ref: 51af15843838
Node: The mimalloc allocator15843964
Ref: c-api/memory mimalloc15844097
Ref: 1ef515844097
Ref: c-api/memory the-mimalloc-allocator15844097
Ref: 525315844097
Node: tracemalloc C API15844458
Ref: c-api/memory tracemalloc-c-api15844581
Ref: 525415844581
Ref: c-api/memory c PyTraceMalloc_Track15844657
Ref: bd415844657
Ref: c-api/memory c PyTraceMalloc_Untrack15845069
Ref: bd515845069
Node: Examples<37>15845360
Ref: c-api/memory examples15845452
Ref: 525515845452
Ref: c-api/memory memoryexamples15845452
Ref: 525615845452
Node: Object Implementation Support15847364
Ref: c-api/objimpl doc15847516
Ref: 525715847516
Ref: c-api/objimpl newtypes15847516
Ref: 525815847516
Ref: c-api/objimpl object-implementation-support15847516
Ref: 525915847516
Ref: c-api/objimpl translation-repo15847516
Ref: 525a15847516
Node: Allocating Objects on the Heap15847823
Ref: c-api/allocation doc15847952
Ref: 525b15847952
Ref: c-api/allocation allocating-objects15847952
Ref: 525c15847952
Ref: c-api/allocation allocating-objects-on-the-heap15847952
Ref: 525d15847952
Ref: c-api/allocation c _PyObject_New15848029
Ref: 525e15848029
Ref: c-api/allocation c _PyObject_NewVar15848139
Ref: 525f15848139
Ref: c-api/allocation c PyObject_Init15848283
Ref: a7915848283
Ref: c-api/allocation c PyObject_InitVar15848633
Ref: 1ae715848633
Ref: c-api/allocation c PyObject_New15848975
Ref: 98f15848975
Ref: c-api/allocation c PyObject_NewVar15849619
Ref: 99015849619
Ref: c-api/allocation c _Py_NoneStruct15850500
Ref: 526015850500
Node: Deprecated aliases<3>15850882
Ref: c-api/allocation deprecated-aliases15850970
Ref: 526115850970
Ref: c-api/allocation c PyObject_NEW15851484
Ref: 526215851484
Ref: c-api/allocation c PyObject_NEW_VAR15851683
Ref: 526315851683
Ref: c-api/allocation c PyObject_INIT15851870
Ref: 1ae515851870
Ref: c-api/allocation c PyObject_INIT_VAR15852072
Ref: 1ae615852072
Ref: c-api/allocation c PyObject_MALLOC15852256
Ref: 526415852256
Ref: c-api/allocation c PyObject_REALLOC15852457
Ref: 526515852457
Ref: c-api/allocation c PyObject_FREE15852650
Ref: 526615852650
Ref: c-api/allocation c PyObject_DEL15852844
Ref: 526715852844
Ref: c-api/allocation c PyObject_Del15853039
Ref: 152015853039
Node: Common Object Structures15853150
Ref: c-api/structures doc15853310
Ref: 526815853310
Ref: c-api/structures common-object-structures15853310
Ref: 526915853310
Ref: c-api/structures common-structs15853310
Ref: 526a15853310
Ref: c-api/structures translation-repo15853310
Ref: 526b15853310
Node: Base object types and macros15853666
Ref: c-api/structures base-object-types-and-macros15853798
Ref: 526c15853798
Ref: c-api/structures c PyObject15854306
Ref: 33a15854306
Ref: c-api/structures c PyVarObject15854990
Ref: 43a615854990
Ref: c-api/structures c PyObject_HEAD15855471
Ref: 132615855471
Ref: c-api/structures c PyObject_VAR_HEAD15855732
Ref: 526d15855732
Ref: c-api/structures c PyBaseObject_Type15856035
Ref: 4c3715856035
Ref: c-api/structures c Py_Is15856223
Ref: 8a715856223
Ref: c-api/structures c Py_IsNone15856453
Ref: 8a815856453
Ref: c-api/structures c Py_IsTrue15856687
Ref: 8a915856687
Ref: c-api/structures c Py_IsFalse15856921
Ref: 8aa15856921
Ref: c-api/structures c Py_TYPE15857158
Ref: 78315857158
Ref: c-api/structures c Py_IS_TYPE15857593
Ref: 194615857593
Ref: c-api/structures c Py_SET_TYPE15857814
Ref: 78415857814
Ref: c-api/structures c Py_SIZE15857951
Ref: 78515857951
Ref: c-api/structures c Py_SET_SIZE15858303
Ref: 78615858303
Ref: c-api/structures c PyObject_HEAD_INIT15858440
Ref: 526e15858440
Ref: c-api/structures c PyVarObject_HEAD_INIT15858658
Ref: 526f15858658
Node: Implementing functions and methods15858942
Ref: c-api/structures implementing-functions-and-methods15859122
Ref: 527015859122
Ref: c-api/structures c PyCFunction15859211
Ref: 14c715859211
Ref: c-api/structures c PyCFunctionWithKeywords15859829
Ref: 4c4d15859829
Ref: c-api/structures c PyCFunctionFast15860256
Ref: 4c4b15860256
Ref: c-api/structures c PyCFunctionFastWithKeywords15860663
Ref: 4c4c15860663
Ref: c-api/structures c PyCMethod15861206
Ref: 76715861206
Ref: c-api/structures c PyMethodDef15861696
Ref: 152615861696
Ref: c-api/structures c PyMethodDef ml_name15861895
Ref: 4bb315861895
Ref: c-api/structures c PyMethodDef ml_meth15861966
Ref: 527315861966
Ref: c-api/structures c PyMethodDef ml_flags15862063
Ref: 527415862063
Ref: c-api/structures c PyMethodDef ml_doc15862165
Ref: 527515862165
Ref: c-api/structures c METH_VARARGS15862877
Ref: 155815862877
Ref: c-api/structures c METH_KEYWORDS15863434
Ref: 4b6c15863434
Ref: c-api/structures meth-varargs-meth-keywords15863687
Ref: 527115863687
Ref: c-api/structures c METH_FASTCALL15864124
Ref: 173115864124
Ref: c-api/structures meth-fastcall-meth-keywords15864686
Ref: 527215864686
Ref: c-api/structures c METH_METHOD15865354
Ref: 97a15865354
Ref: c-api/structures meth-method-meth-fastcall-meth-keywords15865563
Ref: 17a115865563
Ref: c-api/structures c METH_NOARGS15866088
Ref: 152315866088
Ref: c-api/structures c METH_O15866688
Ref: 155715866688
Ref: c-api/structures c METH_CLASS15867325
Ref: 152415867325
Ref: c-api/structures c METH_STATIC15867644
Ref: 152515867644
Ref: c-api/structures c METH_COEXIST15868075
Ref: 14c615868075
Ref: c-api/structures c PyCMethod_Type15868784
Ref: 527615868784
Ref: c-api/structures c PyCMethod_Check15868995
Ref: 527715868995
Ref: c-api/structures c PyCMethod_CheckExact15869185
Ref: 527815869185
Ref: c-api/structures c PyCMethod_New15869339
Ref: 1a5115869339
Ref: c-api/structures c PyCFunction_Type15870468
Ref: 4c5115870468
Ref: c-api/structures c PyCFunction_Check15870723
Ref: 527915870723
Ref: c-api/structures c PyCFunction_CheckExact15870917
Ref: 527a15870917
Ref: c-api/structures c PyCFunction_NewEx15871075
Ref: 1b1f15871075
Ref: c-api/structures c PyCFunction_New15871333
Ref: 1a5715871333
Ref: c-api/structures c PyCFunction_GetFlags15871593
Ref: 4c4e15871593
Ref: c-api/structures c PyCFunction_GET_FLAGS15872008
Ref: 527b15872008
Ref: c-api/structures c PyCFunction_GetFunction15872171
Ref: 4c4f15872171
Ref: c-api/structures c PyCFunction_GET_FUNCTION15872614
Ref: 527c15872614
Ref: c-api/structures c PyCFunction_GetSelf15872783
Ref: 4c5015872783
Ref: c-api/structures c PyCFunction_GET_SELF15873463
Ref: 527d15873463
Node: Accessing attributes of extension types15873652
Ref: c-api/structures accessing-attributes-of-extension-types15873795
Ref: 527e15873795
Ref: c-api/structures c PyMemberDef15873894
Ref: 55215873894
Ref: c-api/structures c PyMemberDef name15874237
Ref: 527f15874237
Ref: c-api/structures c PyMemberDef type15874438
Ref: 4bb415874438
Ref: c-api/structures c PyMemberDef offset15874584
Ref: 528015874584
Ref: c-api/structures c PyMemberDef flags15874733
Ref: 4bb515874733
Ref: c-api/structures c PyMemberDef doc15874857
Ref: 528215874857
Ref: c-api/structures pymemberdef-offsets15875392
Ref: 4fa215875392
Ref: c-api/structures c PyMember_GetOne15876517
Ref: 59015876517
Ref: c-api/structures c PyMember_SetOne15876967
Ref: 59115876967
Node: Member flags15877543
Ref: c-api/structures member-flags15877652
Ref: 528315877652
Ref: c-api/structures pymemberdef-flags15877652
Ref: 528115877652
Ref: c-api/structures c Py_READONLY15877767
Ref: 59415877767
Ref: c-api/structures c Py_AUDIT_READ15877876
Ref: 59515877876
Ref: c-api/structures c Py_RELATIVE_OFFSET15878047
Ref: 55115878047
Node: Member types15879347
Ref: c-api/structures member-types15879493
Ref: 528415879493
Ref: c-api/structures pymemberdef-types15879493
Ref: 178615879493
Ref: c-api/structures c Py_T_BYTE15880375
Ref: 4dfa15880375
Ref: c-api/structures c Py_T_SHORT15880590
Ref: 4e0015880590
Ref: c-api/structures c Py_T_INT15880802
Ref: 59215880802
Ref: c-api/structures c Py_T_LONG15881017
Ref: 4dfd15881017
Ref: c-api/structures c Py_T_LONGLONG15881235
Ref: 4dfe15881235
Ref: c-api/structures c Py_T_UBYTE15881446
Ref: 4e0315881446
Ref: c-api/structures c Py_T_UINT15881659
Ref: 4e0415881659
Ref: c-api/structures c Py_T_USHORT15881875
Ref: 4e0715881875
Ref: c-api/structures c Py_T_ULONG15882088
Ref: 4e0515882088
Ref: c-api/structures c Py_T_ULONGLONG15882306
Ref: 4e0615882306
Ref: c-api/structures c Py_T_PYSSIZET15882519
Ref: 4dff15882519
Ref: c-api/structures c Py_T_FLOAT15882730
Ref: 4dfc15882730
Ref: c-api/structures c Py_T_DOUBLE15882947
Ref: 59315882947
Ref: c-api/structures c Py_T_BOOL15883161
Ref: 4df915883161
Ref: c-api/structures c Py_T_STRING15883378
Ref: 4e0115883378
Ref: c-api/structures c Py_T_STRING_INPLACE15883605
Ref: 4e0215883605
Ref: c-api/structures c Py_T_CHAR15883814
Ref: 4dfb15883814
Ref: c-api/structures c Py_T_OBJECT_EX15884038
Ref: 59715884038
Ref: c-api/structures c T_OBJECT15884959
Ref: 59615884959
Ref: c-api/structures c T_NONE15885174
Ref: 59815885174
Node: Defining Getters and Setters15885263
Ref: c-api/structures defining-getters-and-setters15885388
Ref: 528515885388
Ref: c-api/structures c PyGetSetDef15885465
Ref: bd715885465
Ref: c-api/structures c PyGetSetDef name15885697
Ref: 528615885697
Ref: c-api/structures c PyGetSetDef get15885760
Ref: 528715885760
Ref: c-api/structures c PyGetSetDef set15885848
Ref: 528815885848
Ref: c-api/structures c PyGetSetDef doc15886009
Ref: 528915886009
Ref: c-api/structures c PyGetSetDef closure15886075
Ref: 528a15886075
Ref: c-api/structures c getter15886207
Ref: 4e6615886207
Ref: c-api/structures c setter15886592
Ref: 4e7415886592
Node: Type Object Structures15887072
Ref: c-api/typeobj doc15887238
Ref: 528b15887238
Ref: c-api/typeobj translation-repo15887238
Ref: 528c15887238
Ref: c-api/typeobj type-object-structures15887238
Ref: 528d15887238
Ref: c-api/typeobj type-structs15887238
Ref: 99715887238
Node: Quick Reference15888696
Ref: c-api/typeobj quick-reference15888802
Ref: 528f15888802
Node: “tp slots”15888914
Ref: c-api/typeobj tp-slots15888998
Ref: 529015888998
Ref: c-api/typeobj tp-slots-table15888998
Ref: 529115888998
Ref: “tp slots”-Footnote-115902251
Ref: “tp slots”-Footnote-215902563
Node: sub-slots15903358
Ref: c-api/typeobj id315903464
Ref: 529c15903464
Ref: c-api/typeobj sub-slots15903464
Ref: 529315903464
Node: slot typedefs15913872
Ref: c-api/typeobj slot-typedefs15913955
Ref: 52cc15913955
Ref: c-api/typeobj slot-typedefs-table15913955
Ref: 529215913955
Node: PyTypeObject Definition15921818
Ref: c-api/typeobj pytypeobject-definition15921947
Ref: 52ce15921947
Node: PyObject Slots15925095
Ref: c-api/typeobj pyobject-slots15925226
Ref: 52cf15925226
Ref: c-api/typeobj c PyObject ob_refcnt15925654
Ref: 8a615925654
Ref: c-api/typeobj c PyObject ob_type15926242
Ref: 4b9815926242
Node: PyVarObject Slots15927399
Ref: c-api/typeobj pyvarobject-slots15927525
Ref: 52d015927525
Ref: c-api/typeobj c PyVarObject ob_size15927580
Ref: 4de315927580
Node: PyTypeObject Slots15928068
Ref: c-api/typeobj pytypeobject-slots15928192
Ref: 52d115928192
Ref: c-api/typeobj c PyTypeObject tp_name15928550
Ref: 1a5615928550
Ref: c-api/typeobj c PyTypeObject tp_basicsize15930309
Ref: 99115930309
Ref: c-api/typeobj c PyTypeObject tp_itemsize15930393
Ref: 212115930393
Ref: c-api/typeobj c PyTypeObject tp_dealloc15934504
Ref: 4b8715934504
Ref: c-api/typeobj c Py_tp_dealloc15934687
Ref: 4e4515934687
Ref: c-api/typeobj c PyTypeObject tp_vectorcall_offset15937891
Ref: 4f4615937891
Ref: c-api/typeobj c PyTypeObject tp_getattr15939818
Ref: 4bb715939818
Ref: c-api/typeobj c Py_tp_getattr15940012
Ref: 4e4c15940012
Ref: c-api/typeobj c PyTypeObject tp_setattr15940671
Ref: 4bb815940671
Ref: c-api/typeobj c Py_tp_setattr15940865
Ref: 4e5915940865
Ref: c-api/typeobj c PyTypeObject tp_as_async15941544
Ref: f0315941544
Ref: c-api/typeobj c PyTypeObject tp_repr15942121
Ref: 4bae15942121
Ref: c-api/typeobj c Py_tp_repr15942296
Ref: 4e5715942296
Ref: c-api/typeobj c PyTypeObject tp_as_number15943203
Ref: 99515943203
Ref: c-api/typeobj c PyTypeObject tp_as_sequence15943637
Ref: 529415943637
Ref: c-api/typeobj c PyTypeObject tp_as_mapping15944082
Ref: 529515944082
Ref: c-api/typeobj c PyTypeObject tp_hash15944522
Ref: 4bc015944522
Ref: c-api/typeobj c Py_tp_hash15944697
Ref: 4e4f15944697
Ref: c-api/typeobj c PyTypeObject tp_call15946332
Ref: 55c15946332
Ref: c-api/typeobj c Py_tp_call15946510
Ref: 4e4315946510
Ref: c-api/typeobj c PyTypeObject tp_str15946863
Ref: 4baf15946863
Ref: c-api/typeobj c Py_tp_str15947036
Ref: 4e5b15947036
Ref: c-api/typeobj c PyTypeObject tp_getattro15947933
Ref: 180315947933
Ref: c-api/typeobj c Py_tp_getattro15948130
Ref: 4e4d15948130
Ref: c-api/typeobj c PyTypeObject tp_setattro15948945
Ref: 4bb215948945
Ref: c-api/typeobj c Py_tp_setattro15949142
Ref: 4e5a15949142
Ref: c-api/typeobj c PyTypeObject tp_as_buffer15950083
Ref: 99315950083
Ref: c-api/typeobj c PyTypeObject tp_flags15950516
Ref: 1a1815950516
Ref: c-api/typeobj c Py_TPFLAGS_HEAPTYPE15952462
Ref: 8b715952462
Ref: c-api/typeobj c Py_TPFLAGS_BASETYPE15953276
Ref: 4b9f15953276
Ref: c-api/typeobj c Py_TPFLAGS_READY15953604
Ref: 52d715953604
Ref: c-api/typeobj c Py_TPFLAGS_READYING15953796
Ref: 52d815953796
Ref: c-api/typeobj c Py_TPFLAGS_HAVE_GC15953997
Ref: 78015953997
Ref: c-api/typeobj c Py_TPFLAGS_DEFAULT15955045
Ref: 4b9515955045
Ref: c-api/typeobj c Py_TPFLAGS_METHOD_DESCRIPTOR15955437
Ref: 4df815955437
Ref: c-api/typeobj c Py_TPFLAGS_MANAGED_DICT15956437
Ref: 36e15956437
Ref: c-api/typeobj c Py_TPFLAGS_MANAGED_WEAKREF15957103
Ref: 55d15957103
Ref: c-api/typeobj c Py_TPFLAGS_ITEMS_AT_END15957424
Ref: 54e15957424
Ref: c-api/typeobj c Py_TPFLAGS_LONG_SUBCLASS15958160
Ref: 4f9315958160
Ref: c-api/typeobj c Py_TPFLAGS_LIST_SUBCLASS15958204
Ref: 52da15958204
Ref: c-api/typeobj c Py_TPFLAGS_TUPLE_SUBCLASS15958248
Ref: 52db15958248
Ref: c-api/typeobj c Py_TPFLAGS_BYTES_SUBCLASS15958293
Ref: 52dc15958293
Ref: c-api/typeobj c Py_TPFLAGS_UNICODE_SUBCLASS15958338
Ref: 52dd15958338
Ref: c-api/typeobj c Py_TPFLAGS_DICT_SUBCLASS15958385
Ref: 52de15958385
Ref: c-api/typeobj c Py_TPFLAGS_BASE_EXC_SUBCLASS15958429
Ref: 52df15958429
Ref: c-api/typeobj c Py_TPFLAGS_TYPE_SUBCLASS15958477
Ref: 52e015958477
Ref: c-api/typeobj c Py_TPFLAGS_HAVE_FINALIZE15959084
Ref: 3f515959084
Ref: c-api/typeobj c _Py_TPFLAGS_HAVE_VECTORCALL15959469
Ref: 52e115959469
Ref: c-api/typeobj c Py_TPFLAGS_HAVE_VECTORCALL15959469
Ref: 55715959469
Ref: c-api/typeobj c Py_TPFLAGS_IMMUTABLETYPE15960307
Ref: 3c515960307
Ref: c-api/typeobj c Py_TPFLAGS_DISALLOW_INSTANTIATION15960675
Ref: 58515960675
Ref: c-api/typeobj c Py_TPFLAGS_MAPPING15961804
Ref: 19fe15961804
Ref: c-api/typeobj c Py_TPFLAGS_SEQUENCE15962655
Ref: 19ff15962655
Ref: c-api/typeobj c Py_TPFLAGS_VALID_VERSION_TAG15963507
Ref: 52e215963507
Ref: c-api/typeobj c Py_TPFLAGS_HAVE_VERSION_TAG15963856
Ref: 141715963856
Ref: c-api/typeobj c Py_TPFLAGS_INLINE_VALUES15964105
Ref: 52e315964105
Ref: c-api/typeobj c Py_TPFLAGS_IS_ABSTRACT15964518
Ref: 52e415964518
Ref: c-api/typeobj c Py_TPFLAGS_HAVE_STACKLESS_EXTENSION15964797
Ref: 52d915964797
Ref: c-api/typeobj c PyTypeObject tp_doc15965150
Ref: 4b9615965150
Ref: c-api/typeobj c Py_tp_doc15965313
Ref: 4e4915965313
Ref: c-api/typeobj c PyTypeObject tp_traverse15965587
Ref: 78115965587
Ref: c-api/typeobj c Py_tp_traverse15965784
Ref: 4e5c15965784
Ref: c-api/typeobj c PyTypeObject tp_clear15970048
Ref: 4bac15970048
Ref: c-api/typeobj c Py_tp_clear15970224
Ref: 4e4415970224
Ref: c-api/typeobj c PyTypeObject tp_richcompare15974020
Ref: 4bba15974020
Ref: c-api/typeobj c Py_tp_richcompare15974222
Ref: 4e5815974222
Ref: c-api/typeobj c Py_LT15975118
Ref: 4f3a15975118
Ref: c-api/typeobj c Py_LE15975218
Ref: 4f3b15975218
Ref: c-api/typeobj c Py_EQ15975319
Ref: 4f3c15975319
Ref: c-api/typeobj c Py_NE15975420
Ref: 4f3d15975420
Ref: c-api/typeobj c Py_GT15975521
Ref: 4f3e15975521
Ref: c-api/typeobj c Py_GE15975621
Ref: 4f3f15975621
Ref: c-api/typeobj c Py_RETURN_RICHCOMPARE15975754
Ref: bd215975754
Ref: c-api/typeobj c PyTypeObject tp_weaklistoffset15976999
Ref: 99215976999
Ref: c-api/typeobj c PyTypeObject tp_iter15978529
Ref: 153e15978529
Ref: c-api/typeobj c Py_tp_iter15978707
Ref: 4e5215978707
Ref: c-api/typeobj c PyTypeObject tp_iternext15979160
Ref: 153f15979160
Ref: c-api/typeobj c Py_tp_iternext15979357
Ref: 4e5315979357
Ref: c-api/typeobj c PyTypeObject tp_methods15980110
Ref: 4b9e15980110
Ref: c-api/typeobj c Py_tp_methods15980312
Ref: 4e5515980312
Ref: c-api/typeobj c PyTypeObject tp_members15980752
Ref: 4b9c15980752
Ref: c-api/typeobj c Py_tp_members15980953
Ref: 4e5415980953
Ref: c-api/typeobj c PyTypeObject tp_getset15981428
Ref: 4ba115981428
Ref: c-api/typeobj c Py_tp_getset15981627
Ref: 4e4e15981627
Ref: c-api/typeobj c PyTypeObject tp_base15982095
Ref: 20d715982095
Ref: c-api/typeobj c Py_tp_base15982274
Ref: 4e4115982274
Ref: c-api/typeobj c PyTypeObject tp_dict15983525
Ref: 182b15983525
Ref: c-api/typeobj c PyTypeObject tp_descr_get15985044
Ref: 529615985044
Ref: c-api/typeobj c Py_tp_descr_get15985243
Ref: 4e4715985243
Ref: c-api/typeobj c PyTypeObject tp_descr_set15985487
Ref: 1a5a15985487
Ref: c-api/typeobj c Py_tp_descr_set15985686
Ref: 4e4815985686
Ref: c-api/typeobj c PyTypeObject tp_dictoffset15986025
Ref: 4fa115986025
Ref: c-api/typeobj c PyTypeObject tp_init15987910
Ref: 58415987910
Ref: c-api/typeobj c Py_tp_init15988085
Ref: 4e5015988085
Ref: c-api/typeobj c PyTypeObject tp_alloc15989454
Ref: 4b9b15989454
Ref: c-api/typeobj c Py_tp_alloc15989632
Ref: 4e4015989632
Ref: c-api/typeobj c PyTypeObject tp_new15990279
Ref: 58215990279
Ref: c-api/typeobj c Py_tp_new15990451
Ref: 4e5615990451
Ref: c-api/typeobj c PyTypeObject tp_free15992111
Ref: 4b9a15992111
Ref: c-api/typeobj c Py_tp_free15992286
Ref: 4e4b15992286
Ref: c-api/typeobj c PyTypeObject tp_is_gc15992952
Ref: 529715992952
Ref: c-api/typeobj c Py_tp_is_gc15993128
Ref: 4e5115993128
Ref: c-api/typeobj c PyTypeObject tp_bases15994244
Ref: 529815994244
Ref: c-api/typeobj c Py_tp_bases15994421
Ref: 4e4215994421
Ref: c-api/typeobj c PyTypeObject tp_mro15995104
Ref: 4fa415995104
Ref: c-api/typeobj c PyTypeObject tp_cache15995584
Ref: 4fa515995584
Ref: c-api/typeobj c PyTypeObject tp_subclasses15995744
Ref: 57515995744
Ref: c-api/typeobj c PyTypeObject tp_weaklist15996200
Ref: 4fa615996200
Ref: c-api/typeobj c PyTypeObject tp_del15996776
Ref: 529915996776
Ref: c-api/typeobj c Py_tp_del15996951
Ref: 4e4615996951
Ref: c-api/typeobj c PyTypeObject tp_version_tag15997023
Ref: 529a15997023
Ref: c-api/typeobj c PyTypeObject tp_finalize15997209
Ref: abb15997209
Ref: c-api/typeobj c Py_tp_finalize15997423
Ref: 4e4a15997423
Ref: c-api/typeobj c PyTypeObject tp_vectorcall15998896
Ref: 4fa315998896
Ref: c-api/typeobj c PyTypeObject tp_watched15999445
Ref: 529b15999445
Ref: PyTypeObject Slots-Footnote-115999603
Ref: PyTypeObject Slots-Footnote-215999645
Ref: PyTypeObject Slots-Footnote-315999687
Ref: PyTypeObject Slots-Footnote-415999730
Node: Static Types15999772
Ref: c-api/typeobj id415999889
Ref: 52e515999889
Ref: c-api/typeobj static-types15999889
Ref: 78215999889
Node: Heap Types16000796
Ref: c-api/typeobj heap-types16000919
Ref: 96f16000919
Ref: c-api/typeobj id516000919
Ref: 52e616000919
Node: Number Object Structures16001424
Ref: c-api/typeobj number-object-structures16001560
Ref: 52e716001560
Ref: c-api/typeobj number-structs16001560
Ref: 52d316001560
Ref: c-api/typeobj c PyNumberMethods16001631
Ref: 146c16001631
Ref: c-api/typeobj c PyNumberMethods nb_add16004079
Ref: 4f9616004079
Ref: c-api/typeobj c Py_nb_add16004258
Ref: 4e1616004258
Ref: c-api/typeobj c PyNumberMethods nb_subtract16004260
Ref: 52a316004260
Ref: c-api/typeobj c Py_nb_subtract16004459
Ref: 4e3516004459
Ref: c-api/typeobj c PyNumberMethods nb_multiply16004461
Ref: 52a516004461
Ref: c-api/typeobj c Py_nb_multiply16004660
Ref: 4e2e16004660
Ref: c-api/typeobj c PyNumberMethods nb_remainder16004662
Ref: 52a716004662
Ref: c-api/typeobj c Py_nb_remainder16004863
Ref: 4e3316004863
Ref: c-api/typeobj c PyNumberMethods nb_divmod16004865
Ref: 52a916004865
Ref: c-api/typeobj c Py_nb_divmod16005060
Ref: 4e1916005060
Ref: c-api/typeobj c PyNumberMethods nb_power16005062
Ref: 52aa16005062
Ref: c-api/typeobj c Py_nb_power16005256
Ref: 4e3216005256
Ref: c-api/typeobj c PyNumberMethods nb_negative16005258
Ref: 52ac16005258
Ref: c-api/typeobj c Py_nb_negative16005456
Ref: 4e2f16005456
Ref: c-api/typeobj c PyNumberMethods nb_positive16005458
Ref: 52ad16005458
Ref: c-api/typeobj c Py_nb_positive16005656
Ref: 4e3116005656
Ref: c-api/typeobj c PyNumberMethods nb_absolute16005658
Ref: 52ae16005658
Ref: c-api/typeobj c Py_nb_absolute16005856
Ref: 4e1516005856
Ref: c-api/typeobj c PyNumberMethods nb_bool16005858
Ref: 52af16005858
Ref: c-api/typeobj c Py_nb_bool16006036
Ref: 4e1816006036
Ref: c-api/typeobj c PyNumberMethods nb_invert16006038
Ref: 52b016006038
Ref: c-api/typeobj c Py_nb_invert16006232
Ref: 4e2b16006232
Ref: c-api/typeobj c PyNumberMethods nb_lshift16006234
Ref: 52b116006234
Ref: c-api/typeobj c Py_nb_lshift16006429
Ref: 4e2c16006429
Ref: c-api/typeobj c PyNumberMethods nb_rshift16006431
Ref: 52b316006431
Ref: c-api/typeobj c Py_nb_rshift16006626
Ref: 4e3416006626
Ref: c-api/typeobj c PyNumberMethods nb_and16006628
Ref: 52b516006628
Ref: c-api/typeobj c Py_nb_and16006807
Ref: 4e1716006807
Ref: c-api/typeobj c PyNumberMethods nb_xor16006809
Ref: 52b716006809
Ref: c-api/typeobj c Py_nb_xor16006988
Ref: 4e3716006988
Ref: c-api/typeobj c PyNumberMethods nb_or16006990
Ref: 52b916006990
Ref: c-api/typeobj c Py_nb_or16007167
Ref: 4e3016007167
Ref: c-api/typeobj c PyNumberMethods nb_int16007169
Ref: 52bb16007169
Ref: c-api/typeobj c Py_nb_int16007347
Ref: 4e2a16007347
Ref: c-api/typeobj c PyNumberMethods nb_reserved16007349
Ref: 52bc16007349
Ref: c-api/typeobj c PyNumberMethods nb_float16007410
Ref: 52bd16007410
Ref: c-api/typeobj c Py_nb_float16007602
Ref: 4e1a16007602
Ref: c-api/typeobj c PyNumberMethods nb_inplace_add16007604
Ref: 52a216007604
Ref: c-api/typeobj c Py_nb_inplace_add16007809
Ref: 4e1d16007809
Ref: c-api/typeobj c PyNumberMethods nb_inplace_subtract16007811
Ref: 52a416007811
Ref: c-api/typeobj c Py_nb_inplace_subtract16008026
Ref: 4e2716008026
Ref: c-api/typeobj c PyNumberMethods nb_inplace_multiply16008028
Ref: 52a616008028
Ref: c-api/typeobj c Py_nb_inplace_multiply16008243
Ref: 4e2216008243
Ref: c-api/typeobj c PyNumberMethods nb_inplace_remainder16008245
Ref: 52a816008245
Ref: c-api/typeobj c Py_nb_inplace_remainder16008462
Ref: 4e2516008462
Ref: c-api/typeobj c PyNumberMethods nb_inplace_power16008464
Ref: 52ab16008464
Ref: c-api/typeobj c Py_nb_inplace_power16008674
Ref: 4e2416008674
Ref: c-api/typeobj c PyNumberMethods nb_inplace_lshift16008676
Ref: 52b216008676
Ref: c-api/typeobj c Py_nb_inplace_lshift16008887
Ref: 4e2016008887
Ref: c-api/typeobj c PyNumberMethods nb_inplace_rshift16008889
Ref: 52b416008889
Ref: c-api/typeobj c Py_nb_inplace_rshift16009100
Ref: 4e2616009100
Ref: c-api/typeobj c PyNumberMethods nb_inplace_and16009102
Ref: 52b616009102
Ref: c-api/typeobj c Py_nb_inplace_and16009307
Ref: 4e1e16009307
Ref: c-api/typeobj c PyNumberMethods nb_inplace_xor16009309
Ref: 52b816009309
Ref: c-api/typeobj c Py_nb_inplace_xor16009514
Ref: 4e2916009514
Ref: c-api/typeobj c PyNumberMethods nb_inplace_or16009516
Ref: 52ba16009516
Ref: c-api/typeobj c Py_nb_inplace_or16009719
Ref: 4e2316009719
Ref: c-api/typeobj c PyNumberMethods nb_floor_divide16009721
Ref: 52be16009721
Ref: c-api/typeobj c Py_nb_floor_divide16009928
Ref: 4e1b16009928
Ref: c-api/typeobj c PyNumberMethods nb_true_divide16009930
Ref: 52c016009930
Ref: c-api/typeobj c Py_nb_true_divide16010135
Ref: 4e3616010135
Ref: c-api/typeobj c PyNumberMethods nb_inplace_floor_divide16010137
Ref: 52bf16010137
Ref: c-api/typeobj c Py_nb_inplace_floor_divide16010361
Ref: 4e1f16010361
Ref: c-api/typeobj c PyNumberMethods nb_inplace_true_divide16010362
Ref: 52c116010362
Ref: c-api/typeobj c Py_nb_inplace_true_divide16010584
Ref: 4e2816010584
Ref: c-api/typeobj c PyNumberMethods nb_index16010585
Ref: 146b16010585
Ref: c-api/typeobj c Py_nb_index16010777
Ref: 4e1c16010777
Ref: c-api/typeobj c PyNumberMethods nb_matrix_multiply16010779
Ref: 52c216010779
Ref: c-api/typeobj c Py_nb_matrix_multiply16011011
Ref: 4e2d16011011
Ref: c-api/typeobj c PyNumberMethods nb_inplace_matrix_multiply16011013
Ref: 52c316011013
Ref: c-api/typeobj c Py_nb_inplace_matrix_multiply16011266
Ref: 4e2116011266
Node: Mapping Object Structures16011268
Ref: c-api/typeobj mapping-object-structures16011420
Ref: 52e816011420
Ref: c-api/typeobj mapping-structs16011420
Ref: 52d516011420
Ref: c-api/typeobj c PyMappingMethods16011493
Ref: 4bbf16011493
Ref: c-api/typeobj c PyMappingMethods mp_length16011665
Ref: 52c416011665
Ref: c-api/typeobj c Py_mp_length16011858
Ref: 4e1316011858
Ref: c-api/typeobj c PyMappingMethods mp_subscript16012065
Ref: 1a9d16012065
Ref: c-api/typeobj c Py_mp_subscript16012267
Ref: 4e1416012267
Ref: c-api/typeobj c PyMappingMethods mp_ass_subscript16012571
Ref: 52c516012571
Ref: c-api/typeobj c Py_mp_ass_subscript16012784
Ref: 4e1216012784
Node: Sequence Object Structures16013180
Ref: c-api/typeobj sequence-object-structures16013332
Ref: 52e916013332
Ref: c-api/typeobj sequence-structs16013332
Ref: 52d416013332
Ref: c-api/typeobj c PySequenceMethods16013407
Ref: 4bbe16013407
Ref: c-api/typeobj c PySequenceMethods sq_length16013558
Ref: 4fa016013558
Ref: c-api/typeobj c Py_sq_length16013752
Ref: 4e3e16013752
Ref: c-api/typeobj c PySequenceMethods sq_concat16014008
Ref: 52c616014008
Ref: c-api/typeobj c Py_sq_concat16014205
Ref: 4e3916014205
Ref: c-api/typeobj c PySequenceMethods sq_repeat16014419
Ref: 52c716014419
Ref: c-api/typeobj c Py_sq_repeat16014618
Ref: 4e3f16014618
Ref: c-api/typeobj c PySequenceMethods sq_item16014844
Ref: 1a9c16014844
Ref: c-api/typeobj c Py_sq_item16015039
Ref: 4e3d16015039
Ref: c-api/typeobj c PySequenceMethods sq_ass_item16015709
Ref: 52c816015709
Ref: c-api/typeobj c Py_sq_ass_item16015915
Ref: 4e3816015915
Ref: c-api/typeobj c PySequenceMethods sq_contains16016310
Ref: 52c916016310
Ref: c-api/typeobj c Py_sq_contains16016511
Ref: 4e3a16016511
Ref: c-api/typeobj c PySequenceMethods sq_inplace_concat16016759
Ref: 52ca16016759
Ref: c-api/typeobj c Py_sq_inplace_concat16016972
Ref: 4e3b16016972
Ref: c-api/typeobj c PySequenceMethods sq_inplace_repeat16017426
Ref: 52cb16017426
Ref: c-api/typeobj c Py_sq_inplace_repeat16017641
Ref: 4e3c16017641
Node: Buffer Object Structures16018106
Ref: c-api/typeobj buffer-object-structures16018256
Ref: 52ea16018256
Ref: c-api/typeobj buffer-structs16018256
Ref: 4f6b16018256
Ref: c-api/typeobj c PyBufferProcs16018327
Ref: 4fa716018327
Ref: c-api/typeobj c PyBufferProcs bf_getbuffer16018561
Ref: 76516018561
Ref: c-api/typeobj c Py_bf_getbuffer16018783
Ref: 4e0e16018783
Ref: c-api/typeobj c PyBufferProcs bf_releasebuffer16020580
Ref: 76616020580
Ref: c-api/typeobj c Py_bf_releasebuffer16020814
Ref: 4e0f16020814
Node: Async Object Structures16021857
Ref: c-api/typeobj async-object-structures16021999
Ref: 52eb16021999
Ref: c-api/typeobj async-structs16021999
Ref: 52d216021999
Ref: c-api/typeobj c PyAsyncMethods16022091
Ref: 4f9f16022091
Ref: c-api/typeobj c PyAsyncMethods am_await16022508
Ref: 529d16022508
Ref: c-api/typeobj c Py_am_await16022708
Ref: 4e0c16022708
Ref: c-api/typeobj c PyAsyncMethods am_aiter16023014
Ref: 529e16023014
Ref: c-api/typeobj c Py_am_aiter16023214
Ref: 4e0a16023214
Ref: c-api/typeobj c PyAsyncMethods am_anext16023526
Ref: 529f16023526
Ref: c-api/typeobj c Py_am_anext16023726
Ref: 4e0b16023726
Ref: c-api/typeobj c PyAsyncMethods am_send16023952
Ref: 52a016023952
Ref: c-api/typeobj c Py_am_send16024150
Ref: 4e0d16024150
Node: Slot Type typedefs16024396
Ref: c-api/typeobj id616024526
Ref: 52cd16024526
Ref: c-api/typeobj slot-type-typedefs16024526
Ref: 52ec16024526
Ref: c-api/typeobj c allocfunc16024585
Ref: 4e5d16024585
Ref: c-api/typeobj c destructor16025656
Ref: 4e6116025656
Ref: c-api/typeobj c freefunc16025762
Ref: 50e716025762
Ref: c-api/typeobj c newfunc16025838
Ref: 4e6c16025838
Ref: c-api/typeobj c initproc16026042
Ref: 4e6816026042
Ref: c-api/typeobj c reprfunc16026226
Ref: 4e7016026226
Ref: c-api/typeobj c getattrfunc16026383
Ref: 4e6216026383
Ref: c-api/typeobj c setattrfunc16026596
Ref: 4e7216026596
Ref: c-api/typeobj c getattrofunc16026888
Ref: 4e6316026888
Ref: c-api/typeobj c setattrofunc16027153
Ref: 4e7316027153
Ref: c-api/typeobj c descrgetfunc16027497
Ref: 4e5f16027497
Ref: c-api/typeobj c descrsetfunc16027714
Ref: 4e6016027714
Ref: c-api/typeobj c hashfunc16027913
Ref: 4e6716027913
Ref: c-api/typeobj c richcmpfunc16028071
Ref: 4e7116028071
Ref: c-api/typeobj c getiterfunc16028271
Ref: 4e6516028271
Ref: c-api/typeobj c iternextfunc16028431
Ref: 4e6a16028431
Ref: c-api/typeobj c lenfunc16028596
Ref: 4e6b16028596
Ref: c-api/typeobj c getbufferproc16028727
Ref: 4e6416028727
Ref: c-api/typeobj c releasebufferproc16028894
Ref: 4e6f16028894
Ref: c-api/typeobj c unaryfunc16029061
Ref: 4e7916029061
Ref: c-api/typeobj c binaryfunc16029193
Ref: 4e5e16029193
Ref: c-api/typeobj c sendfunc16029349
Ref: 52a116029349
Ref: c-api/typeobj c ternaryfunc16029529
Ref: 4e7716029529
Ref: c-api/typeobj c ssizeargfunc16029709
Ref: 4e7516029709
Ref: c-api/typeobj c ssizeobjargproc16029868
Ref: 4e7616029868
Ref: c-api/typeobj c objobjproc16030034
Ref: 4e6e16030034
Ref: c-api/typeobj c objobjargproc16030172
Ref: 4e6d16030172
Node: Examples<38>16030336
Ref: c-api/typeobj examples16030434
Ref: 52ed16030434
Ref: c-api/typeobj typedef-examples16030434
Ref: 528e16030434
Node: Supporting Cyclic Garbage Collection16035809
Ref: c-api/gcsupport doc16035942
Ref: 52ee16035942
Ref: c-api/gcsupport supporting-cycle-detection16035942
Ref: 52d616035942
Ref: c-api/gcsupport supporting-cyclic-garbage-collection16035942
Ref: 52ef16035942
Ref: c-api/gcsupport translation-repo16035942
Ref: 52f016035942
Ref: c-api/gcsupport c PyObject_GC_New16038300
Ref: ab716038300
Ref: c-api/gcsupport c PyObject_GC_NewVar16038471
Ref: ab816038471
Ref: c-api/gcsupport c PyUnstable_Object_GC_NewWithExtraData16038654
Ref: 184916038654
Ref: c-api/gcsupport c PyObject_GC_Resize16039653
Ref: 184e16039653
Ref: c-api/gcsupport c PyObject_GC_Track16040036
Ref: 155416040036
Ref: c-api/gcsupport c PyObject_IS_GC16040474
Ref: 98e16040474
Ref: c-api/gcsupport c PyObject_GC_IsTracked16040725
Ref: 98016040725
Ref: c-api/gcsupport c PyObject_GC_IsFinalized16041107
Ref: 98116041107
Ref: c-api/gcsupport c PyObject_GC_Del16041492
Ref: 155316041492
Ref: c-api/gcsupport c PyObject_GC_UnTrack16041702
Ref: 155516041702
Ref: c-api/gcsupport c visitproc16042422
Ref: 4e7a16042422
Ref: c-api/gcsupport c traverseproc16043031
Ref: 4e7816043031
Ref: c-api/gcsupport c Py_VISIT16044023
Ref: 4ba316044023
Ref: c-api/gcsupport c inquiry16044619
Ref: 4e6916044619
Node: Controlling the Garbage Collector State16045242
Ref: c-api/gcsupport controlling-the-garbage-collector-state16045395
Ref: 52f116045395
Ref: c-api/gcsupport c PyGC_Collect16045579
Ref: 99816045579
Ref: c-api/gcsupport c PyGC_Enable16046146
Ref: 8ab16046146
Ref: c-api/gcsupport c PyGC_Disable16046418
Ref: 8ac16046418
Ref: c-api/gcsupport c PyGC_IsEnabled16046692
Ref: 8ad16046692
Node: Querying Garbage Collector State16046986
Ref: c-api/gcsupport querying-garbage-collector-state16047139
Ref: 52f216047139
Ref: c-api/gcsupport c PyUnstable_GC_VisitObjects16047322
Ref: 52f316047322
Ref: c-api/gcsupport c gcvisitobjects_t16048095
Ref: 52f416048095
Node: API and ABI Versioning16048582
Ref: c-api/apiabiversion doc16048733
Ref: 52f516048733
Ref: c-api/apiabiversion api-and-abi-versioning16048733
Ref: 52f616048733
Ref: c-api/apiabiversion apiabiversion16048733
Ref: 45e816048733
Ref: c-api/apiabiversion translation-repo16048733
Ref: 52f716048733
Ref: c-api/apiabiversion c PY_MAJOR_VERSION16049056
Ref: 52f816049056
Ref: c-api/apiabiversion c PY_MINOR_VERSION16049123
Ref: 52f916049123
Ref: c-api/apiabiversion c PY_MICRO_VERSION16049190
Ref: 52fa16049190
Ref: c-api/apiabiversion c PY_RELEASE_LEVEL16049257
Ref: 52fb16049257
Ref: c-api/apiabiversion c PY_RELEASE_SERIAL16049439
Ref: 52fc16049439
Ref: c-api/apiabiversion c PY_VERSION_HEX16049533
Ref: 75a16049533
Ref: c-api/apiabiversion c Py_Version16051452
Ref: 75916051452
Ref: API and ABI Versioning-Footnote-116051892
Node: Monitoring C API16051965
Ref: c-api/monitoring doc16052114
Ref: 52fd16052114
Ref: c-api/monitoring c-api-monitoring16052114
Ref: 15c16052114
Ref: c-api/monitoring monitoring-c-api16052114
Ref: 52fe16052114
Ref: c-api/monitoring translation-repo16052114
Ref: 52ff16052114
Node: Generating Execution Events16052368
Ref: c-api/monitoring generating-execution-events16052486
Ref: 530016052486
Ref: c-api/monitoring c PyMonitoringState16053421
Ref: 31816053421
Ref: c-api/monitoring c PyMonitoring_FirePyStartEvent16053783
Ref: 31916053783
Ref: c-api/monitoring c PyMonitoring_FirePyResumeEvent16053942
Ref: 31a16053942
Ref: c-api/monitoring c PyMonitoring_FirePyReturnEvent16054103
Ref: 31b16054103
Ref: c-api/monitoring c PyMonitoring_FirePyYieldEvent16054282
Ref: 31c16054282
Ref: c-api/monitoring c PyMonitoring_FireCallEvent16054459
Ref: 31d16054459
Ref: c-api/monitoring c PyMonitoring_FireLineEvent16054657
Ref: 31e16054657
Ref: c-api/monitoring c PyMonitoring_FireJumpEvent16054821
Ref: 31f16054821
Ref: c-api/monitoring c PyMonitoring_FireBranchEvent16055008
Ref: 32016055008
Ref: c-api/monitoring c PyMonitoring_FireCReturnEvent16055199
Ref: 32116055199
Ref: c-api/monitoring c PyMonitoring_FirePyThrowEvent16055376
Ref: 32216055376
Ref: c-api/monitoring c PyMonitoring_FireRaiseEvent16055623
Ref: 32316055623
Ref: c-api/monitoring c PyMonitoring_FireCRaiseEvent16055865
Ref: 32416055865
Ref: c-api/monitoring c PyMonitoring_FireReraiseEvent16056110
Ref: 32516056110
Ref: c-api/monitoring c PyMonitoring_FireExceptionHandledEvent16056356
Ref: 32616056356
Ref: c-api/monitoring c PyMonitoring_FirePyUnwindEvent16056622
Ref: 32716056622
Ref: c-api/monitoring c PyMonitoring_FireStopIterationEvent16056871
Ref: 32816056871
Node: Managing the Monitoring State16057287
Ref: c-api/monitoring managing-the-monitoring-state16057380
Ref: 530116057380
Ref: c-api/monitoring c PyMonitoring_EnterScope16057583
Ref: 32916057583
Ref: c-api/monitoring c PY_MONITORING_EVENT_BRANCH16059634
Ref: 530216059634
Ref: c-api/monitoring c PY_MONITORING_EVENT_CALL16059834
Ref: 530316059834
Ref: c-api/monitoring c PY_MONITORING_EVENT_C_RAISE16060037
Ref: 530416060037
Ref: c-api/monitoring c PY_MONITORING_EVENT_C_RETURN16060241
Ref: 530516060241
Ref: c-api/monitoring c PY_MONITORING_EVENT_EXCEPTION_HANDLED16060454
Ref: 530616060454
Ref: c-api/monitoring c PY_MONITORING_EVENT_INSTRUCTION16060661
Ref: 530716060661
Ref: c-api/monitoring c PY_MONITORING_EVENT_JUMP16060861
Ref: 530816060861
Ref: c-api/monitoring c PY_MONITORING_EVENT_LINE16061061
Ref: 530916061061
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_RESUME16061266
Ref: 530a16061266
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_RETURN16061471
Ref: 530b16061471
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_START16061675
Ref: 530c16061675
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_THROW16061879
Ref: 530d16061879
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_UNWIND16062084
Ref: 530e16062084
Ref: c-api/monitoring c PY_MONITORING_EVENT_PY_YIELD16062288
Ref: 530f16062288
Ref: c-api/monitoring c PY_MONITORING_EVENT_RAISE16062489
Ref: 531016062489
Ref: c-api/monitoring c PY_MONITORING_EVENT_RERAISE16062692
Ref: 531116062692
Ref: c-api/monitoring c PY_MONITORING_EVENT_STOP_ITERATION16062902
Ref: 531216062902
Ref: c-api/monitoring c PyMonitoring_ExitScope16063000
Ref: 32a16063000
Ref: c-api/monitoring c PY_MONITORING_IS_INSTRUMENTED_EVENT16063137
Ref: 531316063137
Node: Installing Python modules16063426
Ref: installing/index doc16063551
Ref: 531416063551
Ref: installing/index installing-index16063551
Ref: f2c16063551
Ref: installing/index installing-python-modules16063551
Ref: 531516063551
Ref: installing/index translation-repo16063551
Ref: 531616063551
Ref: Installing Python modules-Footnote-116064677
Node: Key terms16064755
Ref: installing/index key-terms16064846
Ref: 531716064846
Ref: Key terms-Footnote-116066142
Ref: Key terms-Footnote-216066167
Ref: Key terms-Footnote-316066196
Ref: Key terms-Footnote-416066228
Node: Basic usage16066308
Ref: installing/index basic-usage16066421
Ref: 531816066421
Ref: Basic usage-Footnote-116068052
Ref: Basic usage-Footnote-216068089
Node: How do I …?16068138
Ref: installing/index how-do-i16068268
Ref: 531916068268
Node: … install packages just for the current user?16068535
Ref: installing/index install-packages-just-for-the-current-user16068680
Ref: 531a16068680
Node: … install scientific Python packages?16068942
Ref: installing/index install-scientific-python-packages16069160
Ref: 531b16069160
Ref: … install scientific Python packages?-Footnote-116069643
Ref: … install scientific Python packages?-Footnote-216069689
Node: … work with multiple versions of Python installed in parallel?16069735
Ref: installing/index work-with-multiple-versions-of-python-installed-in-parallel16069897
Ref: 531c16069897
Node: Common installation issues16070617
Ref: installing/index common-installation-issues16070727
Ref: 531d16070727
Node: Installing into the system Python on Linux16070902
Ref: installing/index installing-into-the-system-python-on-linux16071033
Ref: 531e16071033
Node: Pip not installed16071600
Ref: installing/index pip-not-installed16071768
Ref: 531f16071768
Ref: Pip not installed-Footnote-116072042
Node: Installing binary extensions16072168
Ref: installing/index installing-binary-extensions16072285
Ref: 532016072285
Ref: Installing binary extensions-Footnote-116073072
Ref: Installing binary extensions-Footnote-216073118
Node: Python HOWTOs16073167
Ref: howto/index doc16073296
Ref: 532116073296
Ref: howto/index how-tos16073296
Ref: 532216073296
Ref: howto/index python-howtos16073296
Ref: 532316073296
Ref: howto/index translation-repo16073296
Ref: 532416073296
Node: A Conceptual Overview of asyncio16074443
Ref: howto/a-conceptual-overview-of-asyncio doc16074571
Ref: 532516074571
Ref: howto/a-conceptual-overview-of-asyncio a-conceptual-overview-of-asyncio16074571
Ref: 348d16074571
Ref: howto/a-conceptual-overview-of-asyncio id116074571
Ref: 532616074571
Ref: A Conceptual Overview of asyncio-Footnote-116075949
Ref: A Conceptual Overview of asyncio-Footnote-216076030
Ref: A Conceptual Overview of asyncio-Footnote-316076123
Node: A conceptual overview part 1 the high-level16076204
Ref: howto/a-conceptual-overview-of-asyncio a-conceptual-overview-part-1-the-high-level16076372
Ref: 532716076372
Node: Event Loop16076732
Ref: howto/a-conceptual-overview-of-asyncio event-loop16076868
Ref: 532816076868
Node: Asynchronous functions and coroutines16078478
Ref: howto/a-conceptual-overview-of-asyncio asynchronous-functions-and-coroutines16078631
Ref: 532916078631
Node: Tasks<2>16081571
Ref: howto/a-conceptual-overview-of-asyncio tasks16081719
Ref: 532a16081719
Node: await16084663
Ref: howto/a-conceptual-overview-of-asyncio await16084765
Ref: 532b16084765
Node: A conceptual overview part 2 the nuts and bolts16088947
Ref: howto/a-conceptual-overview-of-asyncio a-conceptual-overview-part-2-the-nuts-and-bolts16089115
Ref: 532c16089115
Node: The inner workings of coroutines16089605
Ref: howto/a-conceptual-overview-of-asyncio the-inner-workings-of-coroutines16089740
Ref: 532d16089740
Node: Futures<2>16093403
Ref: howto/a-conceptual-overview-of-asyncio futures16093571
Ref: 532e16093571
Node: A homemade asyncio sleep16094848
Ref: howto/a-conceptual-overview-of-asyncio a-homemade-asyncio-sleep16094975
Ref: 532f16094975
Node: Porting Extension Modules to Python 316099601
Ref: howto/cporting doc16099768
Ref: 533016099768
Ref: howto/cporting cporting-howto16099768
Ref: 132916099768
Ref: howto/cporting porting-extension-modules-to-python-316099768
Ref: 533116099768
Ref: howto/cporting translation-repo16099768
Ref: 533216099768
Ref: Porting Extension Modules to Python 3-Footnote-116100559
Ref: Porting Extension Modules to Python 3-Footnote-216100610
Node: Curses Programming with Python16100667
Ref: howto/curses doc16100818
Ref: 533316100818
Ref: howto/curses curses-howto16100818
Ref: 315516100818
Ref: howto/curses curses-programming-with-python16100818
Ref: 533416100818
Ref: howto/curses translation-repo16100818
Ref: 533516100818
Node: What is curses?16101227
Ref: howto/curses what-is-curses16101358
Ref: 533616101358
Ref: What is curses?-Footnote-116103714
Ref: What is curses?-Footnote-216103754
Node: The Python curses module16103798
Ref: howto/curses the-python-curses-module16103874
Ref: 533716103874
Node: Starting and ending a curses application16104701
Ref: howto/curses starting-and-ending-a-curses-application16104857
Ref: 533816104857
Node: Windows and Pads16108133
Ref: howto/curses windows-and-pads16108289
Ref: 533916108289
Node: Displaying Text16112845
Ref: howto/curses displaying-text16112971
Ref: 533a16112971
Node: Attributes and Color16116767
Ref: howto/curses attributes-and-color16116839
Ref: 533b16116839
Node: User Input16121398
Ref: howto/curses user-input16121528
Ref: 533c16121528
Ref: User Input-Footnote-116125348
Node: For More Information16125388
Ref: howto/curses for-more-information16125494
Ref: 533d16125494
Ref: For More Information-Footnote-116126994
Ref: For More Information-Footnote-216127031
Ref: For More Information-Footnote-316127095
Ref: For More Information-Footnote-416127139
Ref: For More Information-Footnote-516127201
Ref: For More Information-Footnote-616127253
Node: Descriptor Guide16127324
Ref: howto/descriptor doc16127495
Ref: 533e16127495
Ref: howto/descriptor descriptor-guide16127495
Ref: 533f16127495
Ref: howto/descriptor descriptorhowto16127495
Ref: 153c16127495
Ref: howto/descriptor translation-repo16127495
Ref: 534016127495
Node: Primer16128649
Ref: howto/descriptor primer16128743
Ref: 534116128743
Node: Simple example A descriptor that returns a constant16129087
Ref: howto/descriptor simple-example-a-descriptor-that-returns-a-constant16129205
Ref: 534216129205
Node: Dynamic lookups16130674
Ref: howto/descriptor dynamic-lookups16130819
Ref: 534316130819
Node: Managed attributes16132221
Ref: howto/descriptor managed-attributes16132331
Ref: 534416132331
Node: Customized names16134986
Ref: howto/descriptor customized-names16135097
Ref: 534516135097
Node: Closing thoughts16137442
Ref: howto/descriptor closing-thoughts16137526
Ref: 534616137526
Node: Complete Practical Example16138916
Ref: howto/descriptor complete-practical-example16139037
Ref: 534716139037
Node: Validator class16139300
Ref: howto/descriptor validator-class16139404
Ref: 534816139404
Node: Custom validators16140430
Ref: howto/descriptor custom-validators16140564
Ref: 534916140564
Ref: Custom validators-Footnote-116143194
Node: Practical application16143263
Ref: howto/descriptor practical-application16143373
Ref: 534a16143373
Node: Technical Tutorial16144761
Ref: howto/descriptor technical-tutorial16144899
Ref: 534b16144899
Node: Abstract16145331
Ref: howto/descriptor abstract16145430
Ref: 534c16145430
Node: Definition and introduction16145745
Ref: howto/descriptor definition-and-introduction16145872
Ref: 534d16145872
Node: Descriptor protocol16147112
Ref: howto/descriptor descriptor-protocol16147264
Ref: 534e16147264
Node: Overview of descriptor invocation16148534
Ref: howto/descriptor overview-of-descriptor-invocation16148686
Ref: 534f16148686
Node: Invocation from an instance16149333
Ref: howto/descriptor invocation-from-an-instance16149489
Ref: 535016149489
Node: Invocation from a class16151994
Ref: howto/descriptor invocation-from-a-class16152138
Ref: 535116152138
Ref: Invocation from a class-Footnote-116152706
Node: Invocation from super16152779
Ref: howto/descriptor invocation-from-super16152923
Ref: 535216152923
Ref: Invocation from super-Footnote-116153557
Ref: Invocation from super-Footnote-216153630
Node: Summary of invocation logic16153710
Ref: howto/descriptor summary-of-invocation-logic16153858
Ref: 535316153858
Node: Automatic name notification16154862
Ref: howto/descriptor automatic-name-notification16155000
Ref: 535416155000
Ref: Automatic name notification-Footnote-116155884
Node: ORM example16155957
Ref: howto/descriptor orm-example16156059
Ref: 535516156059
Ref: ORM example-Footnote-116158072
Ref: ORM example-Footnote-216158144
Node: Pure Python Equivalents16158197
Ref: howto/descriptor pure-python-equivalents16158300
Ref: 535616158300
Node: Properties16158773
Ref: howto/descriptor properties16158873
Ref: 535716158873
Node: Functions and methods16161710
Ref: howto/descriptor functions-and-methods16161835
Ref: 535816161835
Node: Kinds of methods16165107
Ref: howto/descriptor kinds-of-methods16165236
Ref: 535916165236
Node: Static methods16166478
Ref: howto/descriptor static-methods16166599
Ref: 535a16166599
Node: Class methods16168708
Ref: howto/descriptor class-methods16168841
Ref: 535b16168841
Node: Member objects and __slots__16170898
Ref: howto/descriptor member-objects-and-slots16171008
Ref: 535c16171008
Ref: Member objects and __slots__-Footnote-116178631
Node: Debugging C API extensions and CPython Internals with GDB16178687
Ref: howto/gdb_helpers doc16178838
Ref: 535d16178838
Ref: howto/gdb_helpers debugging-c-api-extensions-and-cpython-internals-with-gdb16178838
Ref: 535e16178838
Ref: howto/gdb_helpers gdb16178838
Ref: 535f16178838
Ref: howto/gdb_helpers translation-repo16178838
Ref: 536016178838
Ref: Debugging C API extensions and CPython Internals with GDB-Footnote-116180240
Ref: Debugging C API extensions and CPython Internals with GDB-Footnote-216180276
Node: Prerequisites16180330
Ref: howto/gdb_helpers prerequisites16180488
Ref: 536116180488
Node: Setup with Python built from source16181129
Ref: howto/gdb_helpers setup-with-python-built-from-source16181259
Ref: 536216181259
Node: Setup for Python from a Linux distro16182032
Ref: howto/gdb_helpers setup-for-python-from-a-linux-distro16182162
Ref: 536316182162
Node: Using the Debug build and Development mode16182810
Ref: howto/gdb_helpers using-the-debug-build-and-development-mode16183007
Ref: 536416183007
Node: Using the python-gdb extension16183611
Ref: howto/gdb_helpers using-the-python-gdb-extension16183816
Ref: 536516183816
Node: Pretty-printers16184122
Ref: howto/gdb_helpers pretty-printers16184220
Ref: 536616184220
Node: py-list16188751
Ref: howto/gdb_helpers py-list16188875
Ref: 536716188875
Node: py-up and py-down16189767
Ref: howto/gdb_helpers py-up-and-py-down16189881
Ref: 536816189881
Node: py-bt16194606
Ref: howto/gdb_helpers py-bt16194721
Ref: 536916194721
Node: py-print16196976
Ref: howto/gdb_helpers py-print16197083
Ref: 536a16197083
Node: py-locals16197832
Ref: howto/gdb_helpers py-locals16197925
Ref: 536b16197925
Node: Use with GDB commands16198828
Ref: howto/gdb_helpers use-with-gdb-commands16198982
Ref: 536c16198982
Node: Enum HOWTO16205003
Ref: howto/enum doc16205166
Ref: 536d16205166
Ref: howto/enum enum-howto16205166
Ref: 536e16205166
Ref: howto/enum id116205166
Ref: 536f16205166
Ref: howto/enum translation-repo16205166
Ref: 537016205166
Ref: howto/enum enum-basic-tutorial16205197
Ref: 277316205197
Node: Programmatic access to enumeration members and their attributes16211150
Ref: howto/enum enum-advanced-tutorial16211304
Ref: 277416211304
Ref: howto/enum programmatic-access-to-enumeration-members-and-their-attributes16211304
Ref: 537116211304
Node: Duplicating enum members and values16212056
Ref: howto/enum duplicating-enum-members-and-values16212253
Ref: 537216212253
Node: Ensuring unique enumeration values16213481
Ref: howto/enum ensuring-unique-enumeration-values16213637
Ref: 537316213637
Node: Using automatic values16214191
Ref: howto/enum using-automatic-values16214324
Ref: 537416214324
Node: Iteration<2>16215261
Ref: howto/enum iteration16215374
Ref: 537516215374
Node: Comparisons<3>16216636
Ref: howto/enum comparisons16216773
Ref: 537616216773
Node: Allowed members and attributes of enumerations16217891
Ref: howto/enum allowed-members-and-attributes-of-enumerations16218043
Ref: 537816218043
Node: Restricted Enum subclassing16220185
Ref: howto/enum restricted-enum-subclassing16220340
Ref: 537c16220340
Node: Dataclass support16221454
Ref: howto/enum dataclass-support16221571
Ref: 537e16221571
Ref: howto/enum enum-dataclass-support16221571
Ref: 189c16221571
Node: Pickling16222941
Ref: howto/enum pickling16223048
Ref: 537f16223048
Node: Functional API<3>16223987
Ref: howto/enum functional-api16224097
Ref: 537916224097
Node: Derived Enumerations16227488
Ref: howto/enum derived-enumerations16227621
Ref: 538016227621
Node: IntEnum16227754
Ref: howto/enum intenum16227834
Ref: 537716227834
Node: StrEnum16228959
Ref: howto/enum strenum16229055
Ref: 538116229055
Node: IntFlag16229362
Ref: howto/enum intflag16229455
Ref: 538216229455
Node: Flag16231767
Ref: howto/enum flag16231862
Ref: 538316231862
Node: Others<2>16234101
Ref: howto/enum others16234180
Ref: 538416234180
Node: When to use __new__ vs __init__16236208
Ref: howto/enum new-vs-init16236336
Ref: 537b16236336
Ref: howto/enum when-to-use-new-vs-init16236336
Ref: 538516236336
Node: Finer Points16237596
Ref: howto/enum finer-points16237738
Ref: 538616237738
Node: Supported __dunder__ and _sunder_ names16238067
Ref: howto/enum supported-dunder-and-sunder-names16238179
Ref: 538716238179
Node: _Private__names16238407
Ref: howto/enum private-names16238544
Ref: 538816238544
Node: Enum member type16238714
Ref: howto/enum enum-member-type16238865
Ref: 538916238865
Node: Creating members that are mixed with other data types16239348
Ref: howto/enum creating-members-that-are-mixed-with-other-data-types16239525
Ref: 538a16239525
Node: Boolean value of Enum classes and members16240060
Ref: howto/enum boolean-value-of-enum-classes-and-members16240246
Ref: 538b16240246
Node: Enum classes with methods16240811
Ref: howto/enum enum-classes-with-methods16240969
Ref: 538c16240969
Node: Combining members of Flag16241509
Ref: howto/enum combining-members-of-flag16241650
Ref: 538d16241650
Node: Flag and IntFlag minutia16242212
Ref: howto/enum flag-and-intflag-minutia16242319
Ref: 538e16242319
Node: How are Enums and Flags different?16244853
Ref: howto/enum enum-class-differences16244977
Ref: 277616244977
Ref: howto/enum how-are-enums-and-flags-different16244977
Ref: 538f16244977
Node: Enum Classes16245312
Ref: howto/enum enum-classes16245416
Ref: 539016245416
Node: Flag Classes16245994
Ref: howto/enum flag-classes16246133
Ref: 539116246133
Node: Enum Members aka instances16246499
Ref: howto/enum enum-members-aka-instances16246638
Ref: 539216246638
Node: Flag Members16247026
Ref: howto/enum flag-members16247144
Ref: 539316247144
Node: Enum Cookbook16247779
Ref: howto/enum enum-cookbook16247911
Ref: 277516247911
Ref: howto/enum id216247911
Ref: 539416247911
Node: Omitting values16248376
Ref: howto/enum omitting-values16248461
Ref: 539516248461
Node: Using auto16249255
Ref: howto/enum using-auto16249338
Ref: 539616249338
Node: Using object16249590
Ref: howto/enum using-object16249708
Ref: 539716249708
Node: Using a descriptive string16250361
Ref: howto/enum using-a-descriptive-string16250491
Ref: 539816250491
Node: Using a custom __new__16250778
Ref: howto/enum using-a-custom-new16250887
Ref: 539916250887
Node: OrderedEnum16252755
Ref: howto/enum orderedenum16252866
Ref: 537d16252866
Node: DuplicateFreeEnum16254046
Ref: howto/enum duplicatefreeenum16254156
Ref: 539a16254156
Node: MultiValueEnum16255236
Ref: howto/enum multi-value-enum16255341
Ref: 279316255341
Ref: howto/enum multivalueenum16255341
Ref: 539b16255341
Node: Planet16255924
Ref: howto/enum planet16256022
Ref: 537a16256022
Node: TimePeriod16257083
Ref: howto/enum enum-time-period16257158
Ref: 278c16257158
Ref: howto/enum timeperiod16257158
Ref: 539c16257158
Node: Subclassing EnumType16257774
Ref: howto/enum enumtype-examples16257863
Ref: 277c16257863
Ref: howto/enum subclassing-enumtype16257863
Ref: 539d16257863
Node: Functional Programming HOWTO16258127
Ref: howto/functional doc16258246
Ref: 539e16258246
Ref: howto/functional functional-howto16258246
Ref: 539f16258246
Ref: howto/functional functional-programming-howto16258246
Ref: 53a016258246
Ref: howto/functional translation-repo16258246
Ref: 53a116258246
Node: Introduction<14>16259077
Ref: howto/functional introduction16259179
Ref: 53a216259179
Node: Formal provability16263877
Ref: howto/functional formal-provability16263967
Ref: 53a416263967
Node: Modularity16265881
Ref: howto/functional modularity16266009
Ref: 53a516266009
Node: Ease of debugging and testing16266414
Ref: howto/functional ease-of-debugging-and-testing16266537
Ref: 53a616266537
Node: Composability16267272
Ref: howto/functional composability16267376
Ref: 53a716267376
Node: Iterators<2>16268099
Ref: howto/functional functional-howto-iterators16268255
Ref: 53a316268255
Ref: howto/functional iterators16268255
Ref: 53a816268255
Node: Data Types That Support Iterators16271602
Ref: howto/functional data-types-that-support-iterators16271684
Ref: 53a916271684
Node: Generator expressions and list comprehensions16273648
Ref: howto/functional generator-expressions-and-list-comprehensions16273801
Ref: 53aa16273801
Node: Generators<2>16278358
Ref: howto/functional generators16278520
Ref: 53ab16278520
Ref: Generators<2>-Footnote-116282379
Node: Passing values into a generator16282460
Ref: howto/functional passing-values-into-a-generator16282541
Ref: 53ac16282541
Ref: Passing values into a generator-Footnote-116286480
Node: Built-in functions<2>16286522
Ref: howto/functional built-in-functions16286659
Ref: 53ad16286659
Ref: Built-in functions<2>-Footnote-116290686
Node: The itertools module16290740
Ref: howto/functional the-itertools-module16290884
Ref: 53ae16290884
Node: Creating new iterators16291627
Ref: howto/functional creating-new-iterators16291744
Ref: 53af16291744
Node: Calling functions on elements16294428
Ref: howto/functional calling-functions-on-elements16294572
Ref: 53b016294572
Node: Selecting elements16295384
Ref: howto/functional selecting-elements16295528
Ref: 53b116295528
Node: Combinatoric functions16297019
Ref: howto/functional combinatoric-functions16297151
Ref: 53b216297151
Node: Grouping elements16299484
Ref: howto/functional grouping-elements16299589
Ref: 53b316299589
Node: The functools module16301139
Ref: howto/functional the-functools-module16301303
Ref: 53b416301303
Node: The operator module16304901
Ref: howto/functional the-operator-module16304977
Ref: 53b516304977
Node: Small functions and the lambda expression16305789
Ref: howto/functional small-functions-and-the-lambda-expression16305970
Ref: 53b616305970
Node: Revision History and Acknowledgements16308829
Ref: howto/functional revision-history-and-acknowledgements16309003
Ref: 53b716309003
Node: References<2>16309780
Ref: howto/functional references16309904
Ref: 53b816309904
Node: General16310008
Ref: howto/functional general16310089
Ref: 53b916310089
Node: Python-specific16311150
Ref: howto/functional python-specific16311260
Ref: 53ba16311260
Ref: Python-specific-Footnote-116311734
Ref: Python-specific-Footnote-216311785
Ref: Python-specific-Footnote-316311838
Node: Python documentation16311891
Ref: howto/functional python-documentation16311985
Ref: 53bb16311985
Ref: Python documentation-Footnote-116312384
Ref: Python documentation-Footnote-216312426
Node: Logging HOWTO16312468
Ref: howto/logging doc16312593
Ref: 53bc16312593
Ref: howto/logging id116312593
Ref: 53bd16312593
Ref: howto/logging logging-howto16312593
Ref: 53be16312593
Ref: howto/logging translation-repo16312593
Ref: 53bf16312593
Ref: howto/logging logging-basic-tutorial16312686
Ref: 123a16312686
Node: Basic Logging Tutorial16313066
Ref: howto/logging basic-logging-tutorial16313172
Ref: 53c116313172
Node: When to use logging16313922
Ref: howto/logging when-to-use-logging16314025
Ref: 53c216314025
Node: A simple example16318035
Ref: howto/logging a-simple-example16318164
Ref: 53c316318164
Ref: howto/logging howto-minimal-example16318164
Ref: 53c416318164
Node: Logging to a file16319405
Ref: howto/logging logging-to-a-file16319536
Ref: 53c516319536
Node: Logging variable data16322597
Ref: howto/logging logging-variable-data16322753
Ref: 53c616322753
Node: Changing the format of displayed messages16323570
Ref: howto/logging changing-the-format-of-displayed-messages16323745
Ref: 53c716323745
Node: Displaying the date/time in messages16324739
Ref: howto/logging displaying-the-date-time-in-messages16324903
Ref: 53c816324903
Ref: Displaying the date/time in messages-Footnote-116325954
Node: Next Steps16326013
Ref: howto/logging next-steps16326127
Ref: 53c916326127
Ref: Next Steps-Footnote-116327060
Node: Advanced Logging Tutorial16327104
Ref: howto/logging advanced-logging-tutorial16327236
Ref: 53ca16327236
Ref: howto/logging logging-advanced-tutorial16327236
Ref: 123b16327236
Node: Logging Flow16330624
Ref: howto/logging logging-flow16330714
Ref: 53cb16330714
Node: Loggers16330909
Ref: howto/logging loggers16331016
Ref: 53cc16331016
Node: Handlers16335281
Ref: howto/logging handler-basic16335386
Ref: 53cd16335386
Ref: howto/logging handlers16335386
Ref: 53ce16335386
Node: Formatters16337446
Ref: howto/logging formatters16337563
Ref: 53d016337563
Ref: howto/logging logging logging Formatter __init__16338011
Ref: 53d116338011
Node: Configuring Logging16339714
Ref: howto/logging configuring-logging16339867
Ref: 53d216339867
Node: What happens if no configuration is provided16346413
Ref: howto/logging what-happens-if-no-configuration-is-provided16346589
Ref: 53d316346589
Node: Configuring Logging for a Library16347850
Ref: howto/logging configuring-logging-for-a-library16347998
Ref: 53d416347998
Ref: howto/logging library-config16347998
Ref: 2ed516347998
Node: Logging Levels<2>16350867
Ref: howto/logging logging-levels16350992
Ref: 53d516350992
Node: Custom Levels16353835
Ref: howto/logging custom-levels16353902
Ref: 2e9c16353902
Ref: howto/logging id216353902
Ref: 53d616353902
Node: Useful Handlers16354615
Ref: howto/logging id316354747
Ref: 53d716354747
Ref: howto/logging useful-handlers16354747
Ref: 53cf16354747
Node: Exceptions raised during logging16358773
Ref: howto/logging exceptions-raised-during-logging16358923
Ref: 53d816358923
Ref: howto/logging logging-exceptions16358923
Ref: 53d916358923
Node: Using arbitrary objects as messages16360089
Ref: howto/logging arbitrary-object-messages16360236
Ref: 2e8816360236
Ref: howto/logging using-arbitrary-objects-as-messages16360236
Ref: 53da16360236
Node: Optimization16360848
Ref: howto/logging optimization16360978
Ref: 53db16360978
Node: Other resources16364537
Ref: howto/logging other-resources16364623
Ref: 53dc16364623
Ref: howto/logging tutorial-ref-links16364623
Ref: 53c016364623
Node: Logging Cookbook16364965
Ref: howto/logging-cookbook doc16365086
Ref: 53dd16365086
Ref: howto/logging-cookbook id116365086
Ref: 53de16365086
Ref: howto/logging-cookbook logging-cookbook16365086
Ref: 123c16365086
Ref: howto/logging-cookbook translation-repo16365086
Ref: 53df16365086
Node: Using logging in multiple modules16367229
Ref: howto/logging-cookbook using-logging-in-multiple-modules16367353
Ref: 53e116367353
Node: Logging from multiple threads16370925
Ref: howto/logging-cookbook logging-from-multiple-threads16371090
Ref: 53e216371090
Node: Multiple handlers and formatters16372835
Ref: howto/logging-cookbook multiple-handlers-and-formatters16372999
Ref: 53e316372999
Node: Logging to multiple destinations16375160
Ref: howto/logging-cookbook logging-to-multiple-destinations16375320
Ref: 53e416375320
Ref: howto/logging-cookbook multiple-destinations16375320
Ref: 53e516375320
Node: Custom handling of levels16378487
Ref: howto/logging-cookbook custom-handling-of-levels16378643
Ref: 53e616378643
Ref: howto/logging-cookbook custom-level-handling16378643
Ref: 53e716378643
Node: Configuration server example16384515
Ref: howto/logging-cookbook configuration-server-example16384671
Ref: 53e816384671
Node: Dealing with handlers that block16386231
Ref: howto/logging-cookbook blocking-handlers16386415
Ref: 361916386415
Ref: howto/logging-cookbook dealing-with-handlers-that-block16386415
Ref: 53e916386415
Node: Sending and receiving logging events across a network16390602
Ref: howto/logging-cookbook network-logging16390810
Ref: 53ea16390810
Ref: howto/logging-cookbook sending-and-receiving-logging-events-across-a-network16390810
Ref: 53eb16390810
Node: Running a logging socket listener in production16396343
Ref: howto/logging-cookbook running-a-logging-socket-listener-in-production16396480
Ref: 53ec16396480
Ref: Running a logging socket listener in production-Footnote-116400591
Ref: Running a logging socket listener in production-Footnote-216400623
Ref: Running a logging socket listener in production-Footnote-316400695
Ref: Running a logging socket listener in production-Footnote-416400725
Node: Adding contextual information to your logging output16400797
Ref: howto/logging-cookbook adding-contextual-information-to-your-logging-output16400991
Ref: 53ed16400991
Ref: howto/logging-cookbook context-info16400991
Ref: 2e8f16400991
Node: Using LoggerAdapters to impart contextual information16402078
Ref: howto/logging-cookbook using-loggeradapters-to-impart-contextual-information16402275
Ref: 53ee16402275
Node: Using objects other than dicts to pass contextual information16405530
Ref: howto/logging-cookbook using-objects-other-than-dicts-to-pass-contextual-information16405681
Ref: 53ef16405681
Node: Using Filters to impart contextual information16406145
Ref: howto/logging-cookbook filters-contextual16406342
Ref: 2e8416406342
Ref: howto/logging-cookbook using-filters-to-impart-contextual-information16406342
Ref: 53f016406342
Node: Use of contextvars16410157
Ref: howto/logging-cookbook use-of-contextvars16410342
Ref: 53f116410342
Node: Imparting contextual information in handlers16419920
Ref: howto/logging-cookbook imparting-contextual-information-in-handlers16420101
Ref: 53f216420101
Node: Logging to a single file from multiple processes16421041
Ref: howto/logging-cookbook logging-to-a-single-file-from-multiple-processes16421223
Ref: 53f316421223
Ref: howto/logging-cookbook multiple-processes16421223
Ref: 53f416421223
Node: Using concurrent futures ProcessPoolExecutor16431497
Ref: howto/logging-cookbook using-concurrent-futures-processpoolexecutor16431686
Ref: 53f516431686
Node: Deploying web applications using Gunicorn and uWSGI16432692
Ref: howto/logging-cookbook deploying-web-applications-using-gunicorn-and-uwsgi16432881
Ref: 53f616432881
Ref: Deploying web applications using Gunicorn and uWSGI-Footnote-116433541
Ref: Deploying web applications using Gunicorn and uWSGI-Footnote-216433571
Node: Using file rotation16433624
Ref: howto/logging-cookbook using-file-rotation16433798
Ref: 53f716433798
Node: Use of alternative formatting styles16435701
Ref: howto/logging-cookbook format-styles16435848
Ref: 53f816435848
Ref: howto/logging-cookbook use-of-alternative-formatting-styles16435848
Ref: 53f916435848
Node: Customizing LogRecord16443001
Ref: howto/logging-cookbook custom-logrecord16443189
Ref: 53fa16443189
Ref: howto/logging-cookbook customizing-logrecord16443189
Ref: 53fb16443189
Node: Subclassing QueueHandler and QueueListener- a ZeroMQ example16447097
Ref: howto/logging-cookbook subclassing-queuehandler-and-queuelistener-a-zeromq-example16447308
Ref: 53fc16447308
Ref: howto/logging-cookbook zeromq-handlers16447308
Ref: 53fd16447308
Node: Subclass QueueHandler16447508
Ref: howto/logging-cookbook subclass-queuehandler16447657
Ref: 53fe16447657
Node: Subclass QueueListener16448966
Ref: howto/logging-cookbook subclass-queuelistener16449115
Ref: 53ff16449115
Node: Subclassing QueueHandler and QueueListener- a pynng example16449860
Ref: howto/logging-cookbook pynng-handlers16450091
Ref: 540016450091
Ref: howto/logging-cookbook subclassing-queuehandler-and-queuelistener-a-pynng-example16450091
Ref: 540116450091
Ref: Subclassing QueueHandler and QueueListener- a pynng example-Footnote-116450717
Ref: Subclassing QueueHandler and QueueListener- a pynng example-Footnote-216450757
Node: Subclass QueueListener<2>16450790
Ref: howto/logging-cookbook id316450944
Ref: 540216450944
Node: Subclass QueueHandler<2>16452920
Ref: howto/logging-cookbook id416453074
Ref: 540316453074
Node: An example dictionary-based configuration16456788
Ref: howto/logging-cookbook an-example-dictionary-based-configuration16457021
Ref: 540416457021
Ref: An example dictionary-based configuration-Footnote-116458955
Ref: An example dictionary-based configuration-Footnote-216459041
Node: Using a rotator and namer to customize log rotation processing16459127
Ref: howto/logging-cookbook cookbook-rotator-namer16459341
Ref: 2ee216459341
Ref: howto/logging-cookbook using-a-rotator-and-namer-to-customize-log-rotation-processing16459341
Ref: 540516459341
Node: A more elaborate multiprocessing example16460742
Ref: howto/logging-cookbook a-more-elaborate-multiprocessing-example16460968
Ref: 540616460968
Node: Inserting a BOM into messages sent to a SysLogHandler16470594
Ref: howto/logging-cookbook inserting-a-bom-into-messages-sent-to-a-sysloghandler16470789
Ref: 540716470789
Ref: Inserting a BOM into messages sent to a SysLogHandler-Footnote-116472954
Ref: Inserting a BOM into messages sent to a SysLogHandler-Footnote-216473013
Ref: Inserting a BOM into messages sent to a SysLogHandler-Footnote-316473082
Ref: Inserting a BOM into messages sent to a SysLogHandler-Footnote-416473141
Node: Implementing structured logging16473200
Ref: howto/logging-cookbook implementing-structured-logging16473391
Ref: 540816473391
Node: Customizing handlers with dictConfig16475925
Ref: howto/logging-cookbook custom-handlers16476125
Ref: 540916476125
Ref: howto/logging-cookbook customizing-handlers-with-dictconfig16476125
Ref: 540a16476125
Node: Using particular formatting styles throughout your application16481321
Ref: howto/logging-cookbook formatting-styles16481525
Ref: 2e7816481525
Ref: howto/logging-cookbook using-particular-formatting-styles-throughout-your-application16481525
Ref: 540b16481525
Node: Using LogRecord factories16483527
Ref: howto/logging-cookbook using-logrecord-factories16483688
Ref: 540c16483688
Node: Using custom message objects16484659
Ref: howto/logging-cookbook using-custom-message-objects16484820
Ref: 540d16484820
Node: Configuring filters with dictConfig16487528
Ref: howto/logging-cookbook configuring-filters-with-dictconfig16487727
Ref: 540e16487727
Ref: howto/logging-cookbook filters-dictconfig16487727
Ref: 540f16487727
Node: Customized exception formatting16490680
Ref: howto/logging-cookbook custom-format-exception16490842
Ref: 541016490842
Ref: howto/logging-cookbook customized-exception-formatting16490842
Ref: 541116490842
Node: Speaking logging messages16492907
Ref: howto/logging-cookbook speaking-logging-messages16493094
Ref: 541216493094
Ref: howto/logging-cookbook spoken-messages16493094
Ref: 541316493094
Node: Buffering logging messages and outputting them conditionally16495260
Ref: howto/logging-cookbook buffered-logging16495464
Ref: 541416495464
Ref: howto/logging-cookbook buffering-logging-messages-and-outputting-them-conditionally16495464
Ref: 541516495464
Node: Sending logging messages to email with buffering16501040
Ref: howto/logging-cookbook buffered-smtp16501267
Ref: 541616501267
Ref: howto/logging-cookbook sending-logging-messages-to-email-with-buffering16501267
Ref: 541716501267
Node: Formatting times using UTC GMT via configuration16504833
Ref: howto/logging-cookbook formatting-times-using-utc-gmt-via-configuration16505045
Ref: 541816505045
Ref: howto/logging-cookbook utc-formatting16505045
Ref: 541916505045
Node: Using a context manager for selective logging16506946
Ref: howto/logging-cookbook context-manager16507144
Ref: 541a16507144
Ref: howto/logging-cookbook using-a-context-manager-for-selective-logging16507144
Ref: 541b16507144
Node: A CLI application starter template16511724
Ref: howto/logging-cookbook a-cli-application-starter-template16511894
Ref: 541c16511894
Ref: howto/logging-cookbook starter-template16511894
Ref: 541d16511894
Node: A Qt GUI for logging16517875
Ref: howto/logging-cookbook a-qt-gui-for-logging16518038
Ref: 541e16518038
Ref: howto/logging-cookbook qt-gui16518038
Ref: 541f16518038
Ref: A Qt GUI for logging-Footnote-116528320
Ref: A Qt GUI for logging-Footnote-216528347
Ref: A Qt GUI for logging-Footnote-316528389
Node: Logging to syslog with RFC5424 support16528429
Ref: howto/logging-cookbook logging-to-syslog-with-rfc5424-support16528601
Ref: 542016528601
Ref: Logging to syslog with RFC5424 support-Footnote-116532332
Ref: Logging to syslog with RFC5424 support-Footnote-216532391
Node: How to treat a logger like an output stream16532450
Ref: howto/logging-cookbook how-to-treat-a-logger-like-an-output-stream16532652
Ref: 542116532652
Node: How to uniformly handle newlines in logging output16537328
Ref: howto/logging-cookbook how-to-uniformly-handle-newlines-in-logging-output16537509
Ref: 542216537509
Ref: How to uniformly handle newlines in logging output-Footnote-116541039
Node: Patterns to avoid16541101
Ref: howto/logging-cookbook patterns-to-avoid16541257
Ref: 542316541257
Node: Opening the same log file multiple times16541809
Ref: howto/logging-cookbook opening-the-same-log-file-multiple-times16541980
Ref: 542416541980
Node: Using loggers as attributes in a class or passing them as parameters16543903
Ref: howto/logging-cookbook using-loggers-as-attributes-in-a-class-or-passing-them-as-parameters16544146
Ref: 542516544146
Node: Adding handlers other than NullHandler to a logger in a library16544832
Ref: howto/logging-cookbook adding-handlers-other-than-nullhandler-to-a-logger-in-a-library16545060
Ref: 542616545060
Node: Creating a lot of loggers16545500
Ref: howto/logging-cookbook creating-a-lot-of-loggers16545651
Ref: 542716545651
Node: Other resources<2>16546206
Ref: howto/logging-cookbook cookbook-ref-links16546303
Ref: 53e016546303
Ref: howto/logging-cookbook other-resources16546303
Ref: 542816546303
Node: Regular expression HOWTO16546675
Ref: howto/regex doc16546807
Ref: 542916546807
Ref: howto/regex regex-howto16546807
Ref: 24a716546807
Ref: howto/regex regular-expression-howto16546807
Ref: 542a16546807
Ref: howto/regex translation-repo16546807
Ref: 542b16546807
Node: Introduction<15>16547304
Ref: howto/regex introduction16547405
Ref: 542c16547405
Node: Simple patterns16549010
Ref: howto/regex simple-patterns16549145
Ref: 542d16549145
Node: Matching characters16549640
Ref: howto/regex matching-characters16549736
Ref: 542e16549736
Node: Repeating things16554387
Ref: howto/regex repeating-things16554483
Ref: 542f16554483
Node: Using regular expressions16559561
Ref: howto/regex using-regular-expressions16559698
Ref: 543016559698
Node: Compiling regular expressions16560165
Ref: howto/regex compiling-regular-expressions16560285
Ref: 543116560285
Node: The backslash plague16561502
Ref: howto/regex id116561649
Ref: 543216561649
Ref: howto/regex the-backslash-plague16561649
Ref: 543316561649
Node: Performing matches16564530
Ref: howto/regex performing-matches16564670
Ref: 543416564670
Node: Module-level functions16570206
Ref: howto/regex module-level-functions16570343
Ref: 543516570343
Node: Compilation flags16571546
Ref: howto/regex compilation-flags16571656
Ref: 543616571656
Node: More pattern power16578800
Ref: howto/regex more-pattern-power16578939
Ref: 543816578939
Node: More metacharacters16579304
Ref: howto/regex id216579395
Ref: 543916579395
Ref: howto/regex more-metacharacters16579395
Ref: 543716579395
Node: Grouping16584062
Ref: howto/regex grouping16584192
Ref: 543a16584192
Node: Non-capturing and named groups16587668
Ref: howto/regex non-capturing-and-named-groups16587799
Ref: 543b16587799
Node: Lookahead assertions16592935
Ref: howto/regex lookahead-assertions16593049
Ref: 543c16593049
Node: Modifying strings16596718
Ref: howto/regex modifying-strings16596847
Ref: 543d16596847
Node: Splitting strings16597817
Ref: howto/regex splitting-strings16597915
Ref: 543e16597915
Node: Search and replace16600233
Ref: howto/regex search-and-replace16600331
Ref: 543f16600331
Node: Common problems16604819
Ref: howto/regex common-problems16604938
Ref: 544016604938
Node: Use string methods16605376
Ref: howto/regex use-string-methods16605474
Ref: 544116605474
Node: match versus search16607186
Ref: howto/regex match-versus-search16607317
Ref: 544216607317
Node: Greedy versus non-greedy16608951
Ref: howto/regex greedy-versus-non-greedy16609080
Ref: 544316609080
Node: Using re VERBOSE16611004
Ref: howto/regex using-re-verbose16611105
Ref: 544416611105
Node: Feedback16612632
Ref: howto/regex feedback16612725
Ref: 544516612725
Node: Socket Programming HOWTO16613526
Ref: howto/sockets doc16613660
Ref: 544616613660
Ref: howto/sockets socket-howto16613660
Ref: 367116613660
Ref: howto/sockets socket-programming-howto16613660
Ref: 544716613660
Ref: howto/sockets translation-repo16613660
Ref: 544816613660
Node: Sockets16614258
Ref: howto/sockets sockets16614352
Ref: 544916614352
Node: History16615512
Ref: howto/sockets history16615563
Ref: 544a16615563
Node: Creating a Socket16616138
Ref: howto/sockets creating-a-socket16616255
Ref: 544b16616255
Node: IPC16619511
Ref: howto/sockets ipc16619568
Ref: 544c16619568
Node: Using a Socket16620014
Ref: howto/sockets using-a-socket16620137
Ref: 544d16620137
Node: Binary Data16626276
Ref: howto/sockets binary-data16626338
Ref: 544e16626338
Ref: Binary Data-Footnote-116627625
Node: Disconnecting16627685
Ref: howto/sockets disconnecting16627811
Ref: 544f16627811
Node: When Sockets Die16629287
Ref: howto/sockets when-sockets-die16629353
Ref: 545016629353
Node: Non-blocking Sockets16630232
Ref: howto/sockets non-blocking-sockets16630335
Ref: 545116630335
Node: Sorting Techniques16634156
Ref: howto/sorting doc16634279
Ref: 545216634279
Ref: howto/sorting sorting-techniques16634279
Ref: 545316634279
Ref: howto/sorting sortinghowto16634279
Ref: 233716634279
Ref: howto/sorting translation-repo16634279
Ref: 545416634279
Node: Sorting Basics16634937
Ref: howto/sorting sorting-basics16635028
Ref: 545516635028
Node: Key Functions16635828
Ref: howto/sorting key-functions16635985
Ref: 545616635985
Node: Operator Module Functions and Partial Function Evaluation16637853
Ref: howto/sorting operator-module-functions-and-partial-function-evaluation16638020
Ref: 545716638020
Ref: Operator Module Functions and Partial Function Evaluation-Footnote-116639847
Node: Ascending and Descending16639891
Ref: howto/sorting ascending-and-descending16640077
Ref: 545816640077
Node: Sort Stability and Complex Sorts16640612
Ref: howto/sorting sort-stability-and-complex-sorts16640765
Ref: 545916640765
Ref: Sort Stability and Complex Sorts-Footnote-116642398
Ref: Sort Stability and Complex Sorts-Footnote-216642464
Node: Decorate-Sort-Undecorate16642510
Ref: howto/sorting decorate-sort-undecorate16642659
Ref: 545a16642659
Ref: Decorate-Sort-Undecorate-Footnote-116644310
Node: Comparison Functions16644370
Ref: howto/sorting comparison-functions16644503
Ref: 545b16644503
Ref: Comparison Functions-Footnote-116645474
Node: Odds and Ends<2>16645561
Ref: howto/sorting odds-and-ends16645683
Ref: 545c16645683
Ref: Odds and Ends<2>-Footnote-116647928
Node: Partial Sorts16647970
Ref: howto/sorting partial-sorts16648063
Ref: 545d16648063
Node: Unicode HOWTO16649146
Ref: howto/unicode doc16649300
Ref: 545e16649300
Ref: howto/unicode id116649300
Ref: 545f16649300
Ref: howto/unicode translation-repo16649300
Ref: 546016649300
Ref: howto/unicode unicode-howto16649300
Ref: 12ec16649300
Node: Introduction to Unicode16649700
Ref: howto/unicode introduction-to-unicode16649808
Ref: 546116649808
Node: Definitions16649940
Ref: howto/unicode definitions16650029
Ref: 546216650029
Ref: Definitions-Footnote-116653093
Node: Encodings16653150
Ref: howto/unicode encodings16653261
Ref: 546316653261
Node: References<3>16656942
Ref: howto/unicode references16657033
Ref: 546416657033
Ref: References<3>-Footnote-116657908
Ref: References<3>-Footnote-216657940
Ref: References<3>-Footnote-316657981
Ref: References<3>-Footnote-416658033
Ref: References<3>-Footnote-516658080
Ref: References<3>-Footnote-616658254
Ref: References<3>-Footnote-716658311
Node: Python’s Unicode Support16658355
Ref: howto/unicode python-s-unicode-support16658504
Ref: 546516658504
Node: The String Type16658871
Ref: howto/unicode the-string-type16658977
Ref: 546616658977
Node: Converting to Bytes16662087
Ref: howto/unicode converting-to-bytes16662240
Ref: 546716662240
Node: Unicode Literals in Python Source Code16664080
Ref: howto/unicode unicode-literals-in-python-source-code16664236
Ref: 546816664236
Ref: Unicode Literals in Python Source Code-Footnote-116666341
Node: Unicode Properties16666383
Ref: howto/unicode id216666537
Ref: 546916666537
Ref: howto/unicode unicode-properties16666537
Ref: 237c16666537
Ref: Unicode Properties-Footnote-116668302
Node: Comparing Strings16668372
Ref: howto/unicode comparing-strings16668515
Ref: 546a16668515
Node: Unicode Regular Expressions16671363
Ref: howto/unicode unicode-regular-expressions16671501
Ref: 546b16671501
Node: References<4>16672640
Ref: howto/unicode id316672752
Ref: 546c16672752
Ref: References<4>-Footnote-116673538
Ref: References<4>-Footnote-216673634
Ref: References<4>-Footnote-316673686
Node: Reading and Writing Unicode Data16673755
Ref: howto/unicode reading-and-writing-unicode-data16673901
Ref: 546d16673901
Node: Unicode filenames16677603
Ref: howto/unicode unicode-filenames16677737
Ref: 546e16677737
Node: Tips for Writing Unicode-aware Programs16680193
Ref: howto/unicode tips-for-writing-unicode-aware-programs16680349
Ref: 546f16680349
Node: Converting Between File Encodings16681712
Ref: howto/unicode converting-between-file-encodings16681858
Ref: 547016681858
Node: Files in an Unknown Encoding16682627
Ref: howto/unicode files-in-an-unknown-encoding16682773
Ref: 547116682773
Node: References<5>16683674
Ref: howto/unicode id416683804
Ref: 547216683804
Ref: References<5>-Footnote-116684410
Ref: References<5>-Footnote-216684482
Ref: References<5>-Footnote-316684587
Node: Acknowledgements<10>16684656
Ref: howto/unicode acknowledgements16684767
Ref: 547316684767
Node: HOWTO Fetch Internet Resources Using The urllib Package16685291
Ref: howto/urllib2 doc16685466
Ref: 547416685466
Ref: howto/urllib2 howto-fetch-internet-resources-using-the-urllib-package16685466
Ref: 547516685466
Ref: howto/urllib2 translation-repo16685466
Ref: 547616685466
Ref: howto/urllib2 urllib-howto16685466
Ref: 3c5a16685466
Ref: HOWTO Fetch Internet Resources Using The urllib Package-Footnote-116685880
Node: Introduction<16>16685919
Ref: howto/urllib2 introduction16686049
Ref: 547716686049
Ref: Introduction<16>-Footnote-116687643
Ref: Introduction<16>-Footnote-216687760
Node: Fetching URLs16687819
Ref: howto/urllib2 fetching-urls16687980
Ref: 547816687980
Node: Data16690217
Ref: howto/urllib2 data16690287
Ref: 547916690287
Ref: Data-Footnote-116692938
Node: Headers16693007
Ref: howto/urllib2 headers16693077
Ref: 547a16693077
Ref: Headers-Footnote-116694589
Ref: Headers-Footnote-216694617
Ref: Headers-Footnote-316694827
Ref: Headers-Footnote-416694947
Node: Handling Exceptions<2>16695066
Ref: howto/urllib2 handling-exceptions16695226
Ref: 547c16695226
Node: URLError16695730
Ref: howto/urllib2 urlerror16695815
Ref: 547d16695815
Node: HTTPError16696367
Ref: howto/urllib2 httperror16696475
Ref: 547e16696475
Ref: HTTPError-Footnote-116697368
Node: Error Codes16697427
Ref: howto/urllib2 error-codes16697484
Ref: 547f16697484
Ref: Error Codes-Footnote-116699649
Node: Wrapping it Up16699708
Ref: howto/urllib2 wrapping-it-up16699799
Ref: 548016699799
Node: Number 116700032
Ref: howto/urllib2 number-116700108
Ref: 548116700108
Node: Number 216700734
Ref: howto/urllib2 number-216700810
Ref: 548216700810
Node: info and geturl16701342
Ref: howto/urllib2 info-and-geturl16701509
Ref: 547b16701509
Ref: info and geturl-Footnote-116702441
Node: Openers and Handlers16702479
Ref: howto/urllib2 openers-and-handlers16702644
Ref: 548316702644
Node: Basic Authentication16704292
Ref: howto/urllib2 basic-authentication16704449
Ref: 548416704449
Ref: Basic Authentication-Footnote-116707862
Node: Proxies16707979
Ref: howto/urllib2 proxies16708134
Ref: 548516708134
Ref: Proxies-Footnote-116709166
Ref: Proxies-Footnote-216709468
Node: Sockets and Layers16709635
Ref: howto/urllib2 sockets-and-layers16709779
Ref: 548616709779
Node: Footnotes16710798
Ref: howto/urllib2 footnotes16710926
Ref: 548716710926
Node: An introduction to the ipaddress module16711014
Ref: howto/ipaddress doc16711223
Ref: 548816711223
Ref: howto/ipaddress an-introduction-to-the-ipaddress-module16711223
Ref: 548916711223
Ref: howto/ipaddress ipaddress-howto16711223
Ref: 3e9a16711223
Ref: howto/ipaddress translation-repo16711223
Ref: 548a16711223
Node: Creating Address/Network/Interface objects16711959
Ref: howto/ipaddress creating-address-network-interface-objects16712130
Ref: 548b16712130
Node: A Note on IP Versions16712550
Ref: howto/ipaddress a-note-on-ip-versions16712676
Ref: 548c16712676
Node: IP Host Addresses16713462
Ref: howto/ipaddress ip-host-addresses16713614
Ref: 548d16713614
Node: Defining Networks16714799
Ref: howto/ipaddress defining-networks16714945
Ref: 548e16714945
Node: Host Interfaces16717301
Ref: howto/ipaddress host-interfaces16717421
Ref: 548f16717421
Node: Inspecting Address/Network/Interface Objects16718424
Ref: howto/ipaddress inspecting-address-network-interface-objects16718634
Ref: 549016718634
Node: Networks as lists of Addresses16720982
Ref: howto/ipaddress networks-as-lists-of-addresses16721164
Ref: 549116721164
Node: Comparisons<4>16721961
Ref: howto/ipaddress comparisons16722136
Ref: 549216722136
Node: Using IP Addresses with other modules16722493
Ref: howto/ipaddress using-ip-addresses-with-other-modules16722686
Ref: 549316722686
Node: Getting more detail when instance creation fails16723115
Ref: howto/ipaddress getting-more-detail-when-instance-creation-fails16723285
Ref: 549416723285
Node: Instrumenting CPython with DTrace and SystemTap16725341
Ref: howto/instrumentation doc16725537
Ref: 549516725537
Ref: howto/instrumentation instrumentation16725537
Ref: c8d16725537
Ref: howto/instrumentation instrumenting-cpython-with-dtrace-and-systemtap16725537
Ref: 549616725537
Ref: howto/instrumentation translation-repo16725537
Ref: 549716725537
Node: Enabling the static markers16726718
Ref: howto/instrumentation enabling-the-static-markers16726858
Ref: 549816726858
Node: Static DTrace probes16731056
Ref: howto/instrumentation static-dtrace-probes16731229
Ref: 549916731229
Node: Static SystemTap markers16733668
Ref: howto/instrumentation static-systemtap-markers16733838
Ref: 549a16733838
Node: Available static markers16735882
Ref: howto/instrumentation available-static-markers16736049
Ref: 549b16736049
Ref: howto/instrumentation static-markers16736049
Ref: bd616736049
Node: C Entry Points16738647
Ref: howto/instrumentation c-entry-points16738747
Ref: 549c16738747
Ref: howto/instrumentation c PyDTrace_LINE16739503
Ref: 549d16739503
Ref: howto/instrumentation c PyDTrace_FUNCTION_ENTRY16739633
Ref: 549e16739633
Ref: howto/instrumentation c PyDTrace_FUNCTION_RETURN16739770
Ref: 549f16739770
Ref: howto/instrumentation c PyDTrace_GC_START16739904
Ref: 54a016739904
Ref: howto/instrumentation c PyDTrace_GC_DONE16740119
Ref: 54a116740119
Ref: howto/instrumentation c PyDTrace_INSTANCE_NEW_START16740247
Ref: 54a216740247
Ref: howto/instrumentation c PyDTrace_INSTANCE_NEW_DONE16740446
Ref: 54a316740446
Ref: howto/instrumentation c PyDTrace_INSTANCE_DELETE_START16740640
Ref: 54a416740640
Ref: howto/instrumentation c PyDTrace_INSTANCE_DELETE_DONE16740834
Ref: 54a516740834
Ref: howto/instrumentation c PyDTrace_IMPORT_FIND_LOAD_START16741031
Ref: 54a616741031
Ref: howto/instrumentation c PyDTrace_IMPORT_FIND_LOAD_DONE16741176
Ref: 54a716741176
Ref: howto/instrumentation c PyDTrace_AUDIT16741317
Ref: 54a816741317
Node: C Probing Checks16741396
Ref: howto/instrumentation c-probing-checks16741496
Ref: 54a916741496
Ref: howto/instrumentation c PyDTrace_LINE_ENABLED16741549
Ref: 54aa16741549
Ref: howto/instrumentation c PyDTrace_FUNCTION_ENTRY_ENABLED16741599
Ref: 54ab16741599
Ref: howto/instrumentation c PyDTrace_FUNCTION_RETURN_ENABLED16741659
Ref: 54ac16741659
Ref: howto/instrumentation c PyDTrace_GC_START_ENABLED16741720
Ref: 54ad16741720
Ref: howto/instrumentation c PyDTrace_GC_DONE_ENABLED16741774
Ref: 54ae16741774
Ref: howto/instrumentation c PyDTrace_INSTANCE_NEW_START_ENABLED16741827
Ref: 54af16741827
Ref: howto/instrumentation c PyDTrace_INSTANCE_NEW_DONE_ENABLED16741891
Ref: 54b016741891
Ref: howto/instrumentation c PyDTrace_INSTANCE_DELETE_START_ENABLED16741954
Ref: 54b116741954
Ref: howto/instrumentation c PyDTrace_INSTANCE_DELETE_DONE_ENABLED16742021
Ref: 54b216742021
Ref: howto/instrumentation c PyDTrace_IMPORT_FIND_LOAD_START_ENABLED16742087
Ref: 54b316742087
Ref: howto/instrumentation c PyDTrace_IMPORT_FIND_LOAD_DONE_ENABLED16742155
Ref: 54b416742155
Ref: howto/instrumentation c PyDTrace_AUDIT_ENABLED16742222
Ref: 54b516742222
Node: SystemTap Tapsets16742549
Ref: howto/instrumentation systemtap-tapsets16742704
Ref: 54b616742704
Node: Examples<39>16744322
Ref: howto/instrumentation examples16744444
Ref: 54b716744444
Node: Python support for the Linux perf profiler16745765
Ref: howto/perf_profiling doc16745948
Ref: 184d16745948
Ref: howto/perf_profiling perf-profiling16745948
Ref: 18f16745948
Ref: howto/perf_profiling python-support-for-the-linux-perf-profiler16745948
Ref: 54b816745948
Ref: howto/perf_profiling translation-repo16745948
Ref: 54b916745948
Ref: Python support for the Linux perf profiler-Footnote-116753833
Node: How to enable perf profiling support16753870
Ref: howto/perf_profiling how-to-enable-perf-profiling-support16754024
Ref: 54ba16754024
Node: How to obtain the best results16755166
Ref: howto/perf_profiling how-to-obtain-the-best-results16755363
Ref: 54bb16755363
Node: How to work without frame pointers16756145
Ref: howto/perf_profiling how-to-work-without-frame-pointers16756297
Ref: 54bc16756297
Node: Annotations Best Practices16760161
Ref: howto/annotations doc16760324
Ref: 54bd16760324
Ref: howto/annotations annotations-best-practices16760324
Ref: 54be16760324
Ref: howto/annotations annotations-howto16760324
Ref: 7dd16760324
Ref: howto/annotations translation-repo16760324
Ref: 54bf16760324
Node: Accessing The Annotations Dict Of An Object In Python 3 10 And Newer16761686
Ref: howto/annotations accessing-the-annotations-dict-of-an-object-in-python-3-10-and-newer16761893
Ref: 54c016761893
Node: Accessing The Annotations Dict Of An Object In Python 3 9 And Older16763549
Ref: howto/annotations accessing-the-annotations-dict-of-an-object-in-python-3-9-and-older16763811
Ref: 54c116763811
Node: Manually Un-Stringizing Stringized Annotations16766205
Ref: howto/annotations manually-un-stringizing-stringized-annotations16766455
Ref: 54c216766455
Ref: Manually Un-Stringizing Stringized Annotations-Footnote-116768787
Node: Best Practices For __annotations__ In Any Python Version16768829
Ref: howto/annotations best-practices-for-annotations-in-any-python-version16769034
Ref: 54c316769034
Node: __annotations__ Quirks16769773
Ref: howto/annotations annotations-quirks16769923
Ref: 54c416769923
Node: Isolating Extension Modules16771616
Ref: howto/isolating-extensions doc16771764
Ref: 54c516771764
Ref: howto/isolating-extensions isolating-extension-modules16771764
Ref: 54c616771764
Ref: howto/isolating-extensions isolating-extensions-howto16771764
Ref: 4b6e16771764
Ref: howto/isolating-extensions translation-repo16771764
Ref: 54c716771764
Node: Who should read this16772504
Ref: howto/isolating-extensions who-should-read-this16772610
Ref: 54c816772610
Node: Background<2>16772848
Ref: howto/isolating-extensions background16773009
Ref: 54c916773009
Node: Enter Per-Module State16774620
Ref: howto/isolating-extensions enter-per-module-state16774724
Ref: 54ca16774724
Node: Isolated Module Objects16775895
Ref: howto/isolating-extensions isolated-module-objects16776029
Ref: 54cb16776029
Node: Surprising Edge Cases16777066
Ref: howto/isolating-extensions surprising-edge-cases16777169
Ref: 54cd16777169
Node: Making Modules Safe with Multiple Interpreters16778185
Ref: howto/isolating-extensions making-modules-safe-with-multiple-interpreters16778339
Ref: 54ce16778339
Node: Managing Global State16778658
Ref: howto/isolating-extensions managing-global-state16778796
Ref: 54cc16778796
Node: Managing Per-Module State16779756
Ref: howto/isolating-extensions managing-per-module-state16779952
Ref: 54cf16779952
Ref: Managing Per-Module State-Footnote-116781628
Node: Opt-Out Limiting to One Module Object per Process16781702
Ref: howto/isolating-extensions isolating-extensions-optout16781911
Ref: 50ea16781911
Ref: howto/isolating-extensions opt-out-limiting-to-one-module-object-per-process16781911
Ref: 54d016781911
Node: Module State Access from Functions16783273
Ref: howto/isolating-extensions module-state-access-from-functions16783448
Ref: 54d116783448
Node: Heap Types<2>16784230
Ref: howto/isolating-extensions heap-types16784382
Ref: 54d216784382
Node: Changing Static Types to Heap Types16786048
Ref: howto/isolating-extensions changing-static-types-to-heap-types16786161
Ref: 54d316786161
Node: Defining Heap Types16787141
Ref: howto/isolating-extensions defining-heap-types16787290
Ref: 54d416787290
Node: Garbage-Collection Protocol16787947
Ref: howto/isolating-extensions garbage-collection-protocol16788093
Ref: 54d516788093
Node: tp_traverse in Python 3 8 and lower16789183
Ref: howto/isolating-extensions tp-traverse-in-python-3-8-and-lower16789313
Ref: 54d616789313
Node: Delegating tp_traverse16790081
Ref: howto/isolating-extensions delegating-tp-traverse16790239
Ref: 54d716790239
Node: Defining tp_dealloc16791049
Ref: howto/isolating-extensions defining-tp-dealloc16791194
Ref: 54d816791194
Node: Not overriding tp_free16791966
Ref: howto/isolating-extensions not-overriding-tp-free16792110
Ref: 54d916792110
Node: Avoiding PyObject_New16792317
Ref: howto/isolating-extensions avoiding-pyobject-new16792433
Ref: 54da16792433
Node: Module State Access from Classes16793222
Ref: howto/isolating-extensions module-state-access-from-classes16793389
Ref: 54db16793389
Node: Module State Access from Regular Methods16793962
Ref: howto/isolating-extensions module-state-access-from-regular-methods16794159
Ref: 54dc16794159
Node: Module State Access from Slot Methods Getters and Setters16796672
Ref: howto/isolating-extensions module-state-access-from-slot-methods-getters-and-setters16796865
Ref: 54dd16796865
Node: Lifetime of the Module State16798294
Ref: howto/isolating-extensions lifetime-of-the-module-state16798438
Ref: 54de16798438
Node: Open Issues16798981
Ref: howto/isolating-extensions open-issues16799078
Ref: 54df16799078
Ref: Open Issues-Footnote-116799390
Node: Per-Class Scope16799445
Ref: howto/isolating-extensions per-class-scope16799550
Ref: 54e016799550
Node: Lossless Conversion to Heap Types16799843
Ref: howto/isolating-extensions lossless-conversion-to-heap-types16799948
Ref: 54e116799948
Node: timer file descriptor HOWTO16800190
Ref: howto/timerfd doc16800350
Ref: 54e216800350
Ref: howto/timerfd timer-file-descriptor-howto16800350
Ref: 54e316800350
Ref: howto/timerfd timerfd-howto16800350
Ref: 54e416800350
Ref: howto/timerfd translation-repo16800350
Ref: 54e516800350
Node: Examples<40>16800547
Ref: howto/timerfd examples16800623
Ref: 54e616800623
Node: The Python 2 3 Method Resolution Order16809429
Ref: howto/mro doc16809608
Ref: 54e716809608
Ref: howto/mro python-2-3-mro16809608
Ref: 14f916809608
Ref: howto/mro the-python-2-3-method-resolution-order16809608
Ref: 54e816809608
Ref: howto/mro translation-repo16809608
Ref: 54e916809608
Ref: The Python 2 3 Method Resolution Order-Footnote-116811221
Node: The beginning16811268
Ref: howto/mro the-beginning16811395
Ref: 54ea16811395
Ref: The beginning-Footnote-116815982
Ref: The beginning-Footnote-216816119
Node: The C3 Method Resolution Order16816231
Ref: howto/mro the-c3-method-resolution-order16816379
Ref: 54eb16816379
Node: Examples<41>16818710
Ref: howto/mro examples16818873
Ref: 54ec16818873
Node: Bad Method Resolution Orders16824424
Ref: howto/mro bad-method-resolution-orders16824564
Ref: 54ed16824564
Ref: Bad Method Resolution Orders-Footnote-116830812
Node: The end16830998
Ref: howto/mro the-end16831135
Ref: 54ee16831135
Node: Resources16834314
Ref: howto/mro resources16834414
Ref: 54ef16834414
Node: Python experimental support for free threading16834449
Ref: howto/free-threading-python doc16834643
Ref: 54f016834643
Ref: howto/free-threading-python freethreading-python-howto16834643
Ref: 54f116834643
Ref: howto/free-threading-python python-experimental-support-for-free-threading16834643
Ref: 54f216834643
Ref: howto/free-threading-python translation-repo16834643
Ref: 54f316834643
Ref: Python experimental support for free threading-Footnote-116835925
Node: Installation16835967
Ref: howto/free-threading-python installation16836103
Ref: 54f516836103
Ref: Installation-Footnote-116836689
Node: Identifying free-threaded Python16836753
Ref: howto/free-threading-python identifying-free-threaded-python16836949
Ref: 54f616836949
Node: The global interpreter lock in free-threaded Python16837633
Ref: howto/free-threading-python the-global-interpreter-lock-in-free-threaded-python16837830
Ref: 54f716837830
Node: Thread safety16838580
Ref: howto/free-threading-python thread-safety16838762
Ref: 54f816838762
Node: Known limitations16839554
Ref: howto/free-threading-python known-limitations16839676
Ref: 54f916839676
Node: Immortalization16839929
Ref: howto/free-threading-python immortalization16840023
Ref: 54fa16840023
Node: Frame objects<2>16841134
Ref: howto/free-threading-python frame-objects16841249
Ref: 54fb16841249
Node: Iterators<3>16841694
Ref: howto/free-threading-python iterators16841821
Ref: 54fc16841821
Node: Single-threaded performance16842032
Ref: howto/free-threading-python single-threaded-performance16842134
Ref: 54fd16842134
Ref: Single-threaded performance-Footnote-116842900
Ref: Single-threaded performance-Footnote-216842946
Node: C API Extension Support for Free Threading16842988
Ref: howto/free-threading-extensions doc16843135
Ref: 54fe16843135
Ref: howto/free-threading-extensions c-api-extension-support-for-free-threading16843135
Ref: 54ff16843135
Ref: howto/free-threading-extensions freethreading-extensions-howto16843135
Ref: 54f416843135
Ref: howto/free-threading-extensions translation-repo16843135
Ref: 550016843135
Node: Identifying the Free-Threaded Build in C16843787
Ref: howto/free-threading-extensions identifying-the-free-threaded-build-in-c16843936
Ref: 550116843936
Node: Module Initialization16844643
Ref: howto/free-threading-extensions module-initialization16844823
Ref: 550216844823
Node: Multi-Phase Initialization16845317
Ref: howto/free-threading-extensions multi-phase-initialization16845437
Ref: 550316845437
Node: Single-Phase Initialization16846110
Ref: howto/free-threading-extensions single-phase-initialization16846230
Ref: 550416846230
Node: General API Guidelines16847070
Ref: howto/free-threading-extensions general-api-guidelines16847229
Ref: 550516847229
Node: Container Thread Safety16848050
Ref: howto/free-threading-extensions container-thread-safety16848132
Ref: 550716848132
Node: PyDict_Next16848467
Ref: howto/free-threading-extensions id116848538
Ref: 550816848538
Ref: howto/free-threading-extensions pydict-next16848538
Ref: 550916848538
Node: Borrowed References16849026
Ref: howto/free-threading-extensions borrowed-references16849186
Ref: 550a16849186
Ref: howto/free-threading-extensions id216849241
Ref: 550616849241
Ref: Borrowed References-Footnote-116852031
Node: Memory Allocation APIs16852083
Ref: howto/free-threading-extensions free-threaded-memory-allocation16852246
Ref: 524016852246
Ref: howto/free-threading-extensions memory-allocation-apis16852246
Ref: 550b16852246
Node: Thread State and GIL APIs16852987
Ref: howto/free-threading-extensions thread-state-and-gil-apis16853166
Ref: 550c16853166
Node: Protecting Internal Extension State16854132
Ref: howto/free-threading-extensions protecting-internal-extension-state16854336
Ref: 550d16854336
Ref: Protecting Internal Extension State-Footnote-116855092
Node: Building Extensions for the Free-Threaded Build16855158
Ref: howto/free-threading-extensions building-extensions-for-the-free-threaded-build16855328
Ref: 550e16855328
Ref: Building Extensions for the Free-Threaded Build-Footnote-116855930
Ref: Building Extensions for the Free-Threaded Build-Footnote-216855972
Ref: Building Extensions for the Free-Threaded Build-Footnote-316856017
Node: Limited C API and Stable ABI16856080
Ref: howto/free-threading-extensions limited-c-api-and-stable-abi16856212
Ref: 550f16856212
Ref: Limited C API and Stable ABI-Footnote-116856909
Node: Windows<83>16856970
Ref: howto/free-threading-extensions windows16857102
Ref: 551016857102
Ref: Windows<83>-Footnote-116858730
Node: Python Frequently Asked Questions16858783
Ref: faq/index doc16858899
Ref: 551116858899
Ref: faq/index faq-index16858899
Ref: 1eac16858899
Ref: faq/index python-frequently-asked-questions16858899
Ref: 551216858899
Ref: faq/index translation-repo16858899
Ref: 551316858899
Node: General Python FAQ16859223
Ref: faq/general doc16859335
Ref: 551416859335
Ref: faq/general general-python-faq16859335
Ref: 551516859335
Node: General Information16859447
Ref: faq/general general-information16859554
Ref: 551616859554
Node: What is Python?16860543
Ref: faq/general what-is-python16860662
Ref: 551716860662
Ref: What is Python?-Footnote-116861610
Node: What is the Python Software Foundation?16861662
Ref: faq/general what-is-the-python-software-foundation16861844
Ref: 551816861844
Ref: What is the Python Software Foundation?-Footnote-116862448
Node: Are there copyright restrictions on the use of Python?16862494
Ref: faq/general are-there-copyright-restrictions-on-the-use-of-python16862703
Ref: 551916862703
Ref: Are there copyright restrictions on the use of Python?-Footnote-116863565
Ref: Are there copyright restrictions on the use of Python?-Footnote-216863612
Node: Why was Python created in the first place?16863659
Ref: faq/general why-was-python-created-in-the-first-place16863853
Ref: 551a16863853
Node: What is Python good for?16866185
Ref: faq/general what-is-python-good-for16866375
Ref: 551b16866375
Ref: What is Python good for?-Footnote-116867226
Node: How does the Python version numbering scheme work?16867251
Ref: faq/general faq-version-numbering-scheme16867443
Ref: 551c16867443
Ref: faq/general how-does-the-python-version-numbering-scheme-work16867443
Ref: 551d16867443
Ref: How does the Python version numbering scheme work?-Footnote-116869519
Ref: How does the Python version numbering scheme work?-Footnote-216869593
Node: How do I obtain a copy of the Python source?16869635
Ref: faq/general how-do-i-obtain-a-copy-of-the-python-source16869840
Ref: 551e16869840
Ref: How do I obtain a copy of the Python source?-Footnote-116870622
Node: How do I get documentation on Python?16870665
Ref: faq/general how-do-i-get-documentation-on-python16870878
Ref: 551f16870878
Ref: How do I get documentation on Python?-Footnote-116871442
Node: I’ve never programmed before Is there a Python tutorial?16871478
Ref: faq/general i-ve-never-programmed-before-is-there-a-python-tutorial16871702
Ref: 552016871702
Ref: I’ve never programmed before Is there a Python tutorial?-Footnote-116872113
Node: Is there a newsgroup or mailing list devoted to Python?16872165
Ref: faq/general is-there-a-newsgroup-or-mailing-list-devoted-to-python16872395
Ref: 552116872395
Ref: Is there a newsgroup or mailing list devoted to Python?-Footnote-116873274
Ref: Is there a newsgroup or mailing list devoted to Python?-Footnote-216873335
Node: How do I get a beta test version of Python?16873416
Ref: faq/general how-do-i-get-a-beta-test-version-of-python16873639
Ref: 552216873639
Ref: How do I get a beta test version of Python?-Footnote-116874176
Node: How do I submit bug reports and patches for Python?16874213
Ref: faq/general how-do-i-submit-bug-reports-and-patches-for-python16874448
Ref: 552316874448
Ref: How do I submit bug reports and patches for Python?-Footnote-116874809
Node: Are there any published articles about Python that I can reference?16874846
Ref: faq/general are-there-any-published-articles-about-python-that-i-can-reference16875068
Ref: 552416875068
Ref: Are there any published articles about Python that I can reference?-Footnote-116875620
Node: Are there any books on Python?16875656
Ref: faq/general are-there-any-books-on-python16875872
Ref: 552516875872
Node: Where in the world is www python org located?16876249
Ref: faq/general where-in-the-world-is-www-python-org-located16876422
Ref: 552616876422
Ref: Where in the world is www python org located?-Footnote-116876708
Node: Why is it called Python?16876737
Ref: faq/general why-is-it-called-python16876935
Ref: 552716876935
Ref: Why is it called Python?-Footnote-116877339
Node: Do I have to like “Monty Python’s Flying Circus”?16877390
Ref: faq/general do-i-have-to-like-monty-python-s-flying-circus16877534
Ref: 552816877534
Node: Python in the real world16877684
Ref: faq/general python-in-the-real-world16877791
Ref: 552916877791
Node: How stable is Python?16878171
Ref: faq/general how-stable-is-python16878295
Ref: 552a16878295
Ref: How stable is Python?-Footnote-116879221
Ref: How stable is Python?-Footnote-216879263
Ref: How stable is Python?-Footnote-316879305
Node: How many people are using Python?16879347
Ref: faq/general how-many-people-are-using-python16879530
Ref: 552b16879530
Node: Have any significant projects been done in Python?16880036
Ref: faq/general have-any-significant-projects-been-done-in-python16880258
Ref: 552c16880258
Ref: Have any significant projects been done in Python?-Footnote-116880972
Ref: Have any significant projects been done in Python?-Footnote-216881024
Ref: Have any significant projects been done in Python?-Footnote-316881053
Ref: Have any significant projects been done in Python?-Footnote-416881082
Node: What new developments are expected for Python in the future?16881113
Ref: faq/general what-new-developments-are-expected-for-python-in-the-future16881361
Ref: 552d16881361
Ref: What new developments are expected for Python in the future?-Footnote-116881941
Node: Is it reasonable to propose incompatible changes to Python?16882011
Ref: faq/general is-it-reasonable-to-propose-incompatible-changes-to-python16882261
Ref: 552e16882261
Ref: Is it reasonable to propose incompatible changes to Python?-Footnote-116883065
Node: Is Python a good language for beginning programmers?16883107
Ref: faq/general is-python-a-good-language-for-beginning-programmers16883288
Ref: 552f16883288
Ref: Is Python a good language for beginning programmers?-Footnote-116887109
Ref: Is Python a good language for beginning programmers?-Footnote-216887160
Node: Programming FAQ16887222
Ref: faq/programming doc16887365
Ref: 553016887365
Ref: faq/programming programming-faq16887365
Ref: 553116887365
Ref: faq/programming translation-repo16887365
Ref: 553216887365
Node: General questions16887600
Ref: faq/programming general-questions16887691
Ref: 553316887691
Node: Is there a source code-level debugger with breakpoints and single-stepping?16888031
Ref: faq/programming is-there-a-source-code-level-debugger-with-breakpoints-and-single-stepping16888230
Ref: 553416888230
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-116889644
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-216889688
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-316889741
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-416889787
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-516889836
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-616889875
Ref: Is there a source code-level debugger with breakpoints and single-stepping?-Footnote-716889905
Node: Are there tools to help find bugs or perform static analysis?16889948
Ref: faq/programming are-there-tools-to-help-find-bugs-or-perform-static-analysis16890215
Ref: 553516890215
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-116890608
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-216890645
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-316890684
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-416890726
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-516890757
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-616890792
Ref: Are there tools to help find bugs or perform static analysis?-Footnote-716890821
Node: How can I create a stand-alone binary from a Python script?16890862
Ref: faq/programming faq-create-standalone-binary16891118
Ref: 553616891118
Ref: faq/programming how-can-i-create-a-stand-alone-binary-from-a-python-script16891118
Ref: 553716891118
Ref: How can I create a stand-alone binary from a Python script?-Footnote-116892834
Ref: How can I create a stand-alone binary from a Python script?-Footnote-216892899
Ref: How can I create a stand-alone binary from a Python script?-Footnote-316892927
Ref: How can I create a stand-alone binary from a Python script?-Footnote-416892960
Ref: How can I create a stand-alone binary from a Python script?-Footnote-516893013
Ref: How can I create a stand-alone binary from a Python script?-Footnote-616893065
Ref: How can I create a stand-alone binary from a Python script?-Footnote-716893114
Node: Are there coding standards or a style guide for Python programs?16893146
Ref: faq/programming are-there-coding-standards-or-a-style-guide-for-python-programs16893332
Ref: 553816893332
Ref: Are there coding standards or a style guide for Python programs?-Footnote-116893606
Node: Core language16893648
Ref: faq/programming core-language16893767
Ref: 553916893767
Node: Why am I getting an UnboundLocalError when the variable has a value?16895137
Ref: faq/programming faq-unboundlocalerror16895324
Ref: 218f16895324
Ref: faq/programming why-am-i-getting-an-unboundlocalerror-when-the-variable-has-a-value16895324
Ref: 553a16895324
Node: What are the rules for local and global variables in Python?16897255
Ref: faq/programming what-are-the-rules-for-local-and-global-variables-in-python16897533
Ref: 553b16897533
Node: Why do lambdas defined in a loop with different values all return the same result?16898433
Ref: faq/programming why-do-lambdas-defined-in-a-loop-with-different-values-all-return-the-same-result16898690
Ref: 553c16898690
Node: How do I share global variables across modules?16900608
Ref: faq/programming how-do-i-share-global-variables-across-modules16900868
Ref: 553d16900868
Node: What are the “best practices” for using import in a module?16901671
Ref: faq/programming what-are-the-best-practices-for-using-import-in-a-module16901895
Ref: 553e16901895
Ref: What are the “best practices” for using import in a module?-Footnote-116904720
Ref: What are the “best practices” for using import in a module?-Footnote-216904763
Ref: What are the “best practices” for using import in a module?-Footnote-316904806
Node: Why are default values shared between objects?16904847
Ref: faq/programming why-are-default-values-shared-between-objects16905099
Ref: 553f16905099
Node: How can I pass optional or keyword parameters from one function to another?16907487
Ref: faq/programming how-can-i-pass-optional-or-keyword-parameters-from-one-function-to-another16907732
Ref: 554016907732
Node: What is the difference between arguments and parameters?16908319
Ref: faq/programming faq-argument-vs-parameter16908573
Ref: 554116908573
Ref: faq/programming what-is-the-difference-between-arguments-and-parameters16908573
Ref: 554216908573
Node: Why did changing list ‘y’ also change list ‘x’?16909261
Ref: faq/programming why-did-changing-list-y-also-change-list-x16909508
Ref: 554316909508
Node: How do I write a function with output parameters call by reference ?16912929
Ref: faq/programming how-do-i-write-a-function-with-output-parameters-call-by-reference16913170
Ref: 554416913170
Node: How do you make a higher order function in Python?16915578
Ref: faq/programming how-do-you-make-a-higher-order-function-in-python16915798
Ref: 554516915798
Node: How do I copy an object in Python?16917372
Ref: faq/programming how-do-i-copy-an-object-in-python16917578
Ref: 554616917578
Node: How can I find the methods or attributes of an object?16917985
Ref: faq/programming how-can-i-find-the-methods-or-attributes-of-an-object16918188
Ref: 554716918188
Node: How can my code discover the name of an object?16918514
Ref: faq/programming how-can-my-code-discover-the-name-of-an-object16918734
Ref: 554816918734
Node: What’s up with the comma operator’s precedence?16920379
Ref: faq/programming what-s-up-with-the-comma-operator-s-precedence16920603
Ref: 554916920603
Node: Is there an equivalent of C’s “? ” ternary operator?16921169
Ref: faq/programming is-there-an-equivalent-of-c-s-ternary-operator16921402
Ref: 554a16921402
Node: Is it possible to write obfuscated one-liners in Python?16921997
Ref: faq/programming is-it-possible-to-write-obfuscated-one-liners-in-python16922242
Ref: 554b16922242
Node: What does the slash / in the parameter list of a function mean?16923742
Ref: faq/programming faq-positional-only-arguments16923920
Ref: 232e16923920
Ref: faq/programming what-does-the-slash-in-the-parameter-list-of-a-function-mean16923920
Ref: 554c16923920
Node: Numbers and strings16925020
Ref: faq/programming numbers-and-strings16925136
Ref: 554d16925136
Node: How do I specify hexadecimal and octal integers?16925921
Ref: faq/programming how-do-i-specify-hexadecimal-and-octal-integers16926063
Ref: 554e16926063
Node: Why does -22 // 10 return -3?16926712
Ref: faq/programming why-does-22-10-return-316926921
Ref: 554f16926921
Node: How do I get int literal attribute instead of SyntaxError?16927682
Ref: faq/programming how-do-i-get-int-literal-attribute-instead-of-syntaxerror16927881
Ref: 555016927881
Node: How do I convert a string to a number?16928467
Ref: faq/programming how-do-i-convert-a-string-to-a-number16928675
Ref: 555116928675
Node: How do I convert a number to a string?16930025
Ref: faq/programming how-do-i-convert-a-number-to-a-string16930209
Ref: 555216930209
Node: How do I modify a string in place?16930770
Ref: faq/programming how-do-i-modify-a-string-in-place16930963
Ref: 555316930963
Node: How do I use strings to call functions/methods?16931819
Ref: faq/programming how-do-i-use-strings-to-call-functions-methods16932059
Ref: 555416932059
Node: Is there an equivalent to Perl’s chomp for removing trailing newlines from strings?16933387
Ref: faq/programming is-there-an-equivalent-to-perl-s-chomp-for-removing-trailing-newlines-from-strings16933631
Ref: 555516933631
Node: Is there a scanf or sscanf equivalent?16934398
Ref: faq/programming is-there-a-scanf-or-sscanf-equivalent16934657
Ref: 555616934657
Node: What does UnicodeDecodeError or UnicodeEncodeError error mean?16935322
Ref: faq/programming what-does-unicodedecodeerror-or-unicodeencodeerror-error-mean16935553
Ref: 555716935553
Node: Can I end a raw string with an odd number of backslashes?16935752
Ref: faq/programming can-i-end-a-raw-string-with-an-odd-number-of-backslashes16935936
Ref: 555816935936
Ref: faq/programming faq-programming-raw-string-backslash16935936
Ref: 1d9016935936
Node: Performance<4>16937218
Ref: faq/programming performance16937343
Ref: 555916937343
Node: My program is too slow How do I speed it up?16937560
Ref: faq/programming my-program-is-too-slow-how-do-i-speed-it-up16937732
Ref: 555a16937732
Ref: My program is too slow How do I speed it up?-Footnote-116940613
Ref: My program is too slow How do I speed it up?-Footnote-216940640
Node: What is the most efficient way to concatenate many strings together?16940705
Ref: faq/programming efficient-string-concatenation16940877
Ref: 555b16940877
Ref: faq/programming what-is-the-most-efficient-way-to-concatenate-many-strings-together16940877
Ref: 555c16940877
Node: Sequences tuples/lists16941847
Ref: faq/programming sequences-tuples-lists16941960
Ref: 555d16941960
Node: How do I convert between tuples and lists?16942717
Ref: faq/programming how-do-i-convert-between-tuples-and-lists16942853
Ref: 555e16942853
Node: What’s a negative index?16943700
Ref: faq/programming what-s-a-negative-index16943895
Ref: 555f16943895
Node: How do I iterate over a sequence in reverse order?16944475
Ref: faq/programming how-do-i-iterate-over-a-sequence-in-reverse-order16944669
Ref: 556016944669
Node: How do you remove duplicates from a list?16945018
Ref: faq/programming how-do-you-remove-duplicates-from-a-list16945231
Ref: 556116945231
Node: How do you remove multiple items from a list?16946062
Ref: faq/programming how-do-you-remove-multiple-items-from-a-list16946260
Ref: 556216946260
Node: How do you make an array in Python?16946809
Ref: faq/programming how-do-you-make-an-array-in-python16947006
Ref: 556316947006
Ref: How do you make an array in Python?-Footnote-116948040
Node: How do I create a multidimensional list?16948067
Ref: faq/programming faq-multidimensional-list16948280
Ref: 236216948280
Ref: faq/programming how-do-i-create-a-multidimensional-list16948280
Ref: 556416948280
Ref: How do I create a multidimensional list?-Footnote-116949502
Node: How do I apply a method or function to a sequence of objects?16949529
Ref: faq/programming how-do-i-apply-a-method-or-function-to-a-sequence-of-objects16949786
Ref: 556516949786
Node: Why does a_tuple[i] += [‘item’] raise an exception when the addition works?16950365
Ref: faq/programming faq-augmented-assignment-tuple-error16950659
Ref: 216716950659
Ref: faq/programming why-does-a-tuple-i-item-raise-an-exception-when-the-addition-works16950659
Ref: 556616950659
Node: I want to do a complicated sort can you do a Schwartzian Transform in Python?16953913
Ref: faq/programming i-want-to-do-a-complicated-sort-can-you-do-a-schwartzian-transform-in-python16954198
Ref: 556716954198
Node: How can I sort one list by values from another list?16954683
Ref: faq/programming how-can-i-sort-one-list-by-values-from-another-list16954880
Ref: 556816954880
Node: Objects16955475
Ref: faq/programming objects16955584
Ref: 556916955584
Node: What is a class?16956761
Ref: faq/programming what-is-a-class16956847
Ref: 556a16956847
Node: What is a method?16957573
Ref: faq/programming what-is-a-method16957681
Ref: 556b16957681
Node: What is self?16957990
Ref: faq/programming what-is-self16958165
Ref: 556c16958165
Node: How do I check if an object is an instance of a given class or of a subclass of it?16958607
Ref: faq/programming how-do-i-check-if-an-object-is-an-instance-of-a-given-class-or-of-a-subclass-of-it16958784
Ref: 556e16958784
Node: What is delegation?16961127
Ref: faq/programming what-is-delegation16961375
Ref: 556f16961375
Node: How do I call a method defined in a base class from a derived class that extends it?16963482
Ref: faq/programming how-do-i-call-a-method-defined-in-a-base-class-from-a-derived-class-that-extends-it16963717
Ref: 557016963717
Node: How can I organize my code to make it easier to change the base class?16964339
Ref: faq/programming how-can-i-organize-my-code-to-make-it-easier-to-change-the-base-class16964614
Ref: 557116964614
Node: How do I create static class data and static class methods?16965167
Ref: faq/programming how-do-i-create-static-class-data-and-static-class-methods16965411
Ref: 557216965411
Node: How can I overload constructors or methods in Python?16966980
Ref: faq/programming how-can-i-overload-constructors-or-methods-in-python16967219
Ref: 557316967219
Node: I try to use __spam and I get an error about _SomeClassName__spam16968135
Ref: faq/programming i-try-to-use-spam-and-i-get-an-error-about-someclassname-spam16968385
Ref: 557416968385
Node: My class defines __del__ but it is not called when I delete the object16969590
Ref: faq/programming my-class-defines-del-but-it-is-not-called-when-i-delete-the-object16969841
Ref: 557516969841
Node: How do I get a list of all instances of a given class?16971800
Ref: faq/programming how-do-i-get-a-list-of-all-instances-of-a-given-class16972036
Ref: 557616972036
Node: Why does the result of id appear to be not unique?16972377
Ref: faq/programming why-does-the-result-of-id-appear-to-be-not-unique16972598
Ref: 557716972598
Node: When can I rely on identity tests with the is operator?16973491
Ref: faq/programming when-can-i-rely-on-identity-tests-with-the-is-operator16973730
Ref: 557816973730
Ref: When can I rely on identity tests with the is operator?-Footnote-116977091
Node: How can a subclass control what data is stored in an immutable instance?16977133
Ref: faq/programming how-can-a-subclass-control-what-data-is-stored-in-an-immutable-instance16977350
Ref: 557916977350
Node: How do I cache method calls?16978825
Ref: faq/programming faq-cache-method-calls16978978
Ref: 290316978978
Ref: faq/programming how-do-i-cache-method-calls16978978
Ref: 557a16978978
Node: Modules<5>16981989
Ref: faq/programming modules16982067
Ref: 557b16982067
Node: How do I create a pyc file?16982607
Ref: faq/programming how-do-i-create-a-pyc-file16982728
Ref: 557c16982728
Ref: How do I create a pyc file?-Footnote-116985309
Node: How do I find the current module name?16985351
Ref: faq/programming how-do-i-find-the-current-module-name16985536
Ref: 557d16985536
Node: How can I have modules that mutually import each other?16986094
Ref: faq/programming how-can-i-have-modules-that-mutually-import-each-other16986316
Ref: 557e16986316
Node: __import__ ‘x y z’ returns <module ‘x’>; how do I get z?16988365
Ref: faq/programming import-x-y-z-returns-module-x-how-do-i-get-z16988645
Ref: 557f16988645
Node: When I edit an imported module and reimport it the changes don’t show up Why does this happen?16988935
Ref: faq/programming when-i-edit-an-imported-module-and-reimport-it-the-changes-don-t-show-up-why-does-this-happen16989151
Ref: 558016989151
Node: Design and History FAQ16990599
Ref: faq/design doc16990749
Ref: 558116990749
Ref: faq/design design-and-history-faq16990749
Ref: 558216990749
Ref: faq/design translation-repo16990749
Ref: 558316990749
Node: Why does Python use indentation for grouping of statements?16992848
Ref: faq/design why-does-python-use-indentation-for-grouping-of-statements16993042
Ref: 558416993042
Node: Why am I getting strange results with simple arithmetic operations?16994762
Ref: faq/design why-am-i-getting-strange-results-with-simple-arithmetic-operations16995015
Ref: 558516995015
Node: Why are floating-point calculations so inaccurate?16995190
Ref: faq/design why-are-floating-point-calculations-so-inaccurate16995417
Ref: 558616995417
Node: Why are Python strings immutable?16996950
Ref: faq/design why-are-python-strings-immutable16997181
Ref: 558716997181
Node: Why must ‘self’ be used explicitly in method definitions and calls?16997784
Ref: faq/design why-must-self-be-used-explicitly-in-method-definitions-and-calls16998014
Ref: 558816998014
Ref: faq/design why-self16998014
Ref: 556d16998014
Node: Why can’t I use an assignment in an expression?17000504
Ref: faq/design id117000805
Ref: 558917000805
Ref: faq/design why-can-t-i-use-an-assignment-in-an-expression17000805
Ref: 1dee17000805
Ref: Why can’t I use an assignment in an expression?-Footnote-117001177
Node: Why does Python use methods for some functionality e g list index but functions for other e g len list ?17001219
Ref: faq/design why-does-python-use-methods-for-some-functionality-e-g-list-index-but-functions-for-other-e-g-len-list17001511
Ref: 558a17001511
Node: Why is join a string method instead of a list or tuple method?17002849
Ref: faq/design why-is-join-a-string-method-instead-of-a-list-or-tuple-method17003116
Ref: 558b17003116
Node: How fast are exceptions?17004927
Ref: faq/design how-fast-are-exceptions17005145
Ref: 558c17005145
Node: Why isn’t there a switch or case statement in Python?17005983
Ref: faq/design why-isn-t-there-a-switch-or-case-statement-in-python17006245
Ref: 558d17006245
Node: Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?17007736
Ref: faq/design can-t-you-emulate-threads-in-the-interpreter-instead-of-relying-on-an-os-specific-thread-implementation17008024
Ref: 558e17008024
Ref: Can’t you emulate threads in the interpreter instead of relying on an OS-specific thread implementation?-Footnote-117008671
Node: Why can’t lambda expressions contain statements?17008727
Ref: faq/design why-can-t-lambda-expressions-contain-statements17009024
Ref: 558f17009024
Node: Can Python be compiled to machine code C or some other language?17009889
Ref: faq/design can-python-be-compiled-to-machine-code-c-or-some-other-language17010110
Ref: 559017010110
Ref: Can Python be compiled to machine code C or some other language?-Footnote-117010498
Ref: Can Python be compiled to machine code C or some other language?-Footnote-217010526
Node: How does Python manage memory?17010554
Ref: faq/design how-does-python-manage-memory17010796
Ref: 559117010796
Ref: How does Python manage memory?-Footnote-117012468
Ref: How does Python manage memory?-Footnote-217012499
Node: Why doesn’t CPython use a more traditional garbage collection scheme?17012524
Ref: faq/design why-doesn-t-cpython-use-a-more-traditional-garbage-collection-scheme17012750
Ref: 559217012750
Node: Why isn’t all memory freed when CPython exits?17013701
Ref: faq/design why-isn-t-all-memory-freed-when-cpython-exits17013946
Ref: 559317013946
Node: Why are there separate tuple and list data types?17014641
Ref: faq/design why-are-there-separate-tuple-and-list-data-types17014852
Ref: 559417014852
Node: How are lists implemented in CPython?17016105
Ref: faq/design how-are-lists-implemented-in-cpython17016312
Ref: 559517016312
Node: How are dictionaries implemented in CPython?17017053
Ref: faq/design how-are-dictionaries-implemented-in-cpython17017249
Ref: 559617017249
Node: Why must dictionary keys be immutable?17018218
Ref: faq/design why-must-dictionary-keys-be-immutable17018424
Ref: 559717018424
Node: Why doesn’t list sort return the sorted list?17022632
Ref: faq/design why-doesn-t-list-sort-return-the-sorted-list17022853
Ref: 559817022853
Node: How do you specify and enforce an interface spec in Python?17023697
Ref: faq/design how-do-you-specify-and-enforce-an-interface-spec-in-python17023901
Ref: 559917023901
Node: Why is there no goto?17026235
Ref: faq/design why-is-there-no-goto17026447
Ref: 559a17026447
Node: Why can’t raw strings r-strings end with a backslash?17027584
Ref: faq/design why-can-t-raw-strings-r-strings-end-with-a-backslash17027812
Ref: 559b17027812
Node: Why doesn’t Python have a “with” statement for attribute assignments?17028913
Ref: faq/design why-doesn-t-python-have-a-with-statement-for-attribute-assignments17029170
Ref: 559c17029170
Node: Why don’t generators support the with statement?17031635
Ref: faq/design why-don-t-generators-support-the-with-statement17031899
Ref: 559d17031899
Node: Why are colons required for the if/while/def/class statements?17032317
Ref: faq/design why-are-colons-required-for-the-if-while-def-class-statements17032566
Ref: 559e17032566
Node: Why does Python allow commas at the end of lists and tuples?17033311
Ref: faq/design why-does-python-allow-commas-at-the-end-of-lists-and-tuples17033501
Ref: 559f17033501
Node: Library and Extension FAQ17034602
Ref: faq/library doc17034760
Ref: 55a017034760
Ref: faq/library library-and-extension-faq17034760
Ref: 55a117034760
Ref: faq/library translation-repo17034760
Ref: 55a217034760
Node: General Library Questions17035009
Ref: faq/library general-library-questions17035117
Ref: 55a317035117
Node: How do I find a module or application to perform task X?17035629
Ref: faq/library how-do-i-find-a-module-or-application-to-perform-task-x17035812
Ref: 55a417035812
Ref: How do I find a module or application to perform task X?-Footnote-117036399
Ref: How do I find a module or application to perform task X?-Footnote-217036424
Node: Where is the math py socket py regex py etc source file?17036455
Ref: faq/library where-is-the-math-py-socket-py-regex-py-etc-source-file17036696
Ref: 55a517036696
Node: How do I make a Python script executable on Unix?17037480
Ref: faq/library how-do-i-make-a-python-script-executable-on-unix17037710
Ref: 55a617037710
Node: Is there a curses/termcap package for Python?17039187
Ref: faq/library is-there-a-curses-termcap-package-for-python17039410
Ref: 55a717039410
Ref: Is there a curses/termcap package for Python?-Footnote-117040205
Node: Is there an equivalent to C’s onexit in Python?17040265
Ref: faq/library is-there-an-equivalent-to-c-s-onexit-in-python17040475
Ref: 55a817040475
Node: Why don’t my signal handlers work?17040695
Ref: faq/library why-don-t-my-signal-handlers-work17040851
Ref: 55a917040851
Node: Common tasks17041176
Ref: faq/library common-tasks17041300
Ref: 55aa17041300
Node: How do I test a Python program or component?17041498
Ref: faq/library how-do-i-test-a-python-program-or-component17041647
Ref: 55ab17041647
Node: How do I create documentation from doc strings?17043598
Ref: faq/library how-do-i-create-documentation-from-doc-strings17043797
Ref: 55ac17043797
Ref: How do I create documentation from doc strings?-Footnote-117044173
Ref: How do I create documentation from doc strings?-Footnote-217044213
Node: How do I get a single keypress at a time?17044248
Ref: faq/library how-do-i-get-a-single-keypress-at-a-time17044394
Ref: 55ad17044394
Node: Threads17044640
Ref: faq/library threads17044758
Ref: 55ae17044758
Node: How do I program using threads?17045086
Ref: faq/library how-do-i-program-using-threads17045205
Ref: 55af17045205
Node: None of my threads seem to run why?17045506
Ref: faq/library none-of-my-threads-seem-to-run-why17045691
Ref: 55b017045691
Node: How do I parcel out work among a bunch of worker threads?17047240
Ref: faq/library how-do-i-parcel-out-work-among-a-bunch-of-worker-threads17047446
Ref: 55b117047446
Node: What kinds of global value mutation are thread-safe?17050046
Ref: faq/library what-kinds-of-global-value-mutation-are-thread-safe17050267
Ref: 55b217050267
Node: Can’t we get rid of the Global Interpreter Lock?17051774
Ref: faq/library can-t-we-get-rid-of-the-global-interpreter-lock17051929
Ref: 55b317051929
Ref: Can’t we get rid of the Global Interpreter Lock?-Footnote-117054944
Ref: Can’t we get rid of the Global Interpreter Lock?-Footnote-217054986
Ref: Can’t we get rid of the Global Interpreter Lock?-Footnote-317055029
Node: Input and Output<2>17055089
Ref: faq/library input-and-output17055223
Ref: 55b417055223
Node: How do I delete a file? And other file questions…17055858
Ref: faq/library how-do-i-delete-a-file-and-other-file-questions17055995
Ref: 55b517055995
Node: How do I copy a file?17057246
Ref: faq/library how-do-i-copy-a-file17057427
Ref: 55b617057427
Ref: How do I copy a file?-Footnote-117057902
Ref: How do I copy a file?-Footnote-217057973
Node: How do I read or write binary data?17058025
Ref: faq/library how-do-i-read-or-write-binary-data17058223
Ref: 55b717058223
Node: I can’t seem to use os read on a pipe created with os popen ; why?17059420
Ref: faq/library i-can-t-seem-to-use-os-read-on-a-pipe-created-with-os-popen-why17059635
Ref: 55b817059635
Node: How do I access the serial RS232 port?17060151
Ref: faq/library how-do-i-access-the-serial-rs232-port17060393
Ref: 55b917060393
Ref: How do I access the serial RS232 port?-Footnote-117060718
Node: Why doesn’t closing sys stdout stdin stderr really close it?17060761
Ref: faq/library why-doesn-t-closing-sys-stdout-stdin-stderr-really-close-it17060926
Ref: 55ba17060926
Node: Network/Internet Programming17062154
Ref: faq/library network-internet-programming17062290
Ref: 55bb17062290
Node: What WWW tools are there for Python?17062642
Ref: faq/library what-www-tools-are-there-for-python17062806
Ref: 55bc17062806
Node: What module should I use to help with generating HTML?17063249
Ref: faq/library what-module-should-i-use-to-help-with-generating-html17063462
Ref: 55bd17063462
Ref: What module should I use to help with generating HTML?-Footnote-117063707
Node: How do I send mail from a Python script?17063759
Ref: faq/library how-do-i-send-mail-from-a-python-script17063994
Ref: 55be17063994
Node: How do I avoid blocking in the connect method of a socket?17065335
Ref: faq/library how-do-i-avoid-blocking-in-the-connect-method-of-a-socket17065507
Ref: 55bf17065507
Ref: How do I avoid blocking in the connect method of a socket?-Footnote-117066839
Node: Databases17066868
Ref: faq/library databases17067009
Ref: 55c017067009
Node: Are there any interfaces to database packages in Python?17067170
Ref: faq/library are-there-any-interfaces-to-database-packages-in-python17067331
Ref: 55c117067331
Ref: Are there any interfaces to database packages in Python?-Footnote-117067837
Node: How do you implement persistent objects in Python?17067894
Ref: faq/library how-do-you-implement-persistent-objects-in-python17068055
Ref: 55c217068055
Node: Mathematics and Numerics17068456
Ref: faq/library mathematics-and-numerics17068560
Ref: 55c317068560
Node: How do I generate random numbers in Python?17068683
Ref: faq/library how-do-i-generate-random-numbers-in-python17068787
Ref: 55c417068787
Node: Extending/Embedding FAQ17069740
Ref: faq/extending doc17069897
Ref: 55c517069897
Ref: faq/extending extending-embedding-faq17069897
Ref: 55c617069897
Ref: faq/extending translation-repo17069897
Ref: 55c717069897
Node: Can I create my own functions in C?17071385
Ref: faq/extending can-i-create-my-own-functions-in-c17071526
Ref: 55c817071526
Node: Can I create my own functions in C++?17071886
Ref: faq/extending id117072082
Ref: 55c917072082
Node: Writing C is hard; are there any alternatives?17072469
Ref: faq/extending c-wrapper-software17072683
Ref: 55ca17072683
Ref: faq/extending writing-c-is-hard-are-there-any-alternatives17072683
Ref: 55cb17072683
Node: How can I execute arbitrary Python statements from C?17073045
Ref: faq/extending how-can-i-execute-arbitrary-python-statements-from-c17073279
Ref: 55cc17073279
Node: How can I evaluate an arbitrary Python expression from C?17073818
Ref: faq/extending how-can-i-evaluate-an-arbitrary-python-expression-from-c17074053
Ref: 55cd17074053
Node: How do I extract C values from a Python object?17074369
Ref: faq/extending how-do-i-extract-c-values-from-a-python-object17074616
Ref: 55ce17074616
Node: How do I use Py_BuildValue to create a tuple of arbitrary length?17075862
Ref: faq/extending how-do-i-use-py-buildvalue-to-create-a-tuple-of-arbitrary-length17076094
Ref: 55cf17076094
Node: How do I call an object’s method from C?17076301
Ref: faq/extending how-do-i-call-an-object-s-method-from-c17076571
Ref: 55d017076571
Node: How do I catch the output from PyErr_Print or anything that prints to stdout/stderr ?17077795
Ref: faq/extending how-do-i-catch-the-output-from-pyerr-print-or-anything-that-prints-to-stdout-stderr17078050
Ref: 55d117078050
Node: How do I access a module written in Python from C?17079263
Ref: faq/extending how-do-i-access-a-module-written-in-python-from-c17079522
Ref: 55d217079522
Node: How do I interface to C++ objects from Python?17080350
Ref: faq/extending how-do-i-interface-to-c-objects-from-python17080586
Ref: 55d317080586
Node: I added a module using the Setup file and the make fails; why?17081158
Ref: faq/extending i-added-a-module-using-the-setup-file-and-the-make-fails-why17081372
Ref: 55d417081372
Node: How do I debug an extension?17081722
Ref: faq/extending how-do-i-debug-an-extension17081974
Ref: 55d517081974
Node: I want to compile a Python module on my Linux system but some files are missing Why?17082525
Ref: faq/extending i-want-to-compile-a-python-module-on-my-linux-system-but-some-files-are-missing-why17082777
Ref: 55d617082777
Node: How do I tell “incomplete input” from “invalid input”?17083184
Ref: faq/extending how-do-i-tell-incomplete-input-from-invalid-input17083476
Ref: 55d717083476
Node: How do I find undefined g++ symbols __builtin_new or __pure_virtual?17084445
Ref: faq/extending how-do-i-find-undefined-g-symbols-builtin-new-or-pure-virtual17084763
Ref: 55d817084763
Node: Can I create an object class with some methods implemented in C and others in Python e g through inheritance ?17085151
Ref: faq/extending can-i-create-an-object-class-with-some-methods-implemented-in-c-and-others-in-python-e-g-through-inheritance17085398
Ref: 55d917085398
Node: Python on Windows FAQ17085952
Ref: faq/windows doc17086110
Ref: 55da17086110
Ref: faq/windows python-on-windows-faq17086110
Ref: 55db17086110
Ref: faq/windows translation-repo17086110
Ref: 55dc17086110
Ref: faq/windows windows-faq17086110
Ref: 55dd17086110
Node: How do I run a Python program under Windows?17086766
Ref: faq/windows faq-run-program-under-windows17086917
Ref: 55de17086917
Ref: faq/windows how-do-i-run-a-python-program-under-windows17086917
Ref: 55df17086917
Node: How do I make Python scripts executable?17090485
Ref: faq/windows how-do-i-make-python-scripts-executable17090693
Ref: 55e017090693
Node: Why does Python sometimes take so long to start?17091255
Ref: faq/windows why-does-python-sometimes-take-so-long-to-start17091468
Ref: 55e117091468
Node: How do I make an executable from a Python script?17092347
Ref: faq/windows how-do-i-make-an-executable-from-a-python-script17092554
Ref: 55e217092554
Node: Is a * pyd file the same as a DLL?17092805
Ref: faq/windows is-a-pyd-file-the-same-as-a-dll17093014
Ref: 55e317093014
Node: How can I embed Python into a Windows application?17094011
Ref: faq/windows how-can-i-embed-python-into-a-windows-application17094235
Ref: 55e417094235
Node: How do I keep editors from inserting tabs into my Python source?17098694
Ref: faq/windows how-do-i-keep-editors-from-inserting-tabs-into-my-python-source17098931
Ref: 55e517098931
Ref: How do I keep editors from inserting tabs into my Python source?-Footnote-117099807
Node: How do I check for a keypress without blocking?17099849
Ref: faq/windows how-do-i-check-for-a-keypress-without-blocking17100103
Ref: 55e617100103
Node: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?17100452
Ref: faq/windows how-do-i-solve-the-missing-api-ms-win-crt-runtime-l1-1-0-dll-error17100633
Ref: 55e717100633
Ref: How do I solve the missing api-ms-win-crt-runtime-l1-1-0 dll error?-Footnote-117101139
Node: Graphic User Interface FAQ17101197
Ref: faq/gui doc17101381
Ref: 55e817101381
Ref: faq/gui graphic-user-interface-faq17101381
Ref: 55e917101381
Ref: faq/gui translation-repo17101381
Ref: 55ea17101381
Node: General GUI Questions17101544
Ref: faq/gui general-gui-questions17101672
Ref: 55eb17101672
Node: What GUI toolkits exist for Python?17101731
Ref: faq/gui what-gui-toolkits-exist-for-python17101885
Ref: 55ec17101885
Ref: What GUI toolkits exist for Python?-Footnote-117102592
Ref: What GUI toolkits exist for Python?-Footnote-217102634
Ref: What GUI toolkits exist for Python?-Footnote-317102661
Ref: What GUI toolkits exist for Python?-Footnote-417102740
Node: Tkinter questions17102822
Ref: faq/gui tkinter-questions17102946
Ref: 55ed17102946
Node: How do I freeze Tkinter applications?17103212
Ref: faq/gui how-do-i-freeze-tkinter-applications17103363
Ref: 55ee17103363
Node: Can I have Tk events handled while waiting for I/O?17103948
Ref: faq/gui can-i-have-tk-events-handled-while-waiting-for-i-o17104158
Ref: 55ef17104158
Node: I can’t get key bindings to work in Tkinter why?17104633
Ref: faq/gui i-can-t-get-key-bindings-to-work-in-tkinter-why17104797
Ref: 55f017104797
Node: “Why is Python Installed on my Computer?” FAQ17105362
Ref: faq/installed doc17105516
Ref: 55f117105516
Ref: faq/installed translation-repo17105516
Ref: 55f217105516
Ref: faq/installed why-is-python-installed-on-my-computer-faq17105516
Ref: 55f317105516
Node: What is Python?<2>17105740
Ref: faq/installed what-is-python17105891
Ref: 55f417105891
Ref: What is Python?<2>-Footnote-117106370
Node: Why is Python installed on my machine?17106422
Ref: faq/installed why-is-python-installed-on-my-machine17106602
Ref: 55f517106602
Node: Can I delete Python?17107687
Ref: faq/installed can-i-delete-python17107840
Ref: 55f617107840
Node: Deprecations17108568
Ref: deprecations/index doc17108679
Ref: 55f717108679
Ref: deprecations/index deprecations17108679
Ref: 55f817108679
Ref: deprecations/index translation-repo17108679
Ref: 55f917108679
Node: Pending Removal in Python 3 14<5>17109167
Ref: deprecations/index pending-removal-in-python-3-1417109291
Ref: 55fa17109291
Ref: Pending Removal in Python 3 14<5>-Footnote-117113747
Ref: Pending Removal in Python 3 14<5>-Footnote-217113802
Ref: Pending Removal in Python 3 14<5>-Footnote-317113857
Ref: Pending Removal in Python 3 14<5>-Footnote-417113912
Ref: Pending Removal in Python 3 14<5>-Footnote-517113967
Ref: Pending Removal in Python 3 14<5>-Footnote-617114023
Ref: Pending Removal in Python 3 14<5>-Footnote-717114079
Ref: Pending Removal in Python 3 14<5>-Footnote-817114134
Ref: Pending Removal in Python 3 14<5>-Footnote-917114189
Ref: Pending Removal in Python 3 14<5>-Footnote-1017114245
Ref: Pending Removal in Python 3 14<5>-Footnote-1117114301
Ref: Pending Removal in Python 3 14<5>-Footnote-1217114357
Node: Pending Removal in Python 3 15<5>17114413
Ref: deprecations/index pending-removal-in-python-3-1517114579
Ref: 55fb17114579
Ref: Pending Removal in Python 3 15<5>-Footnote-117118901
Ref: Pending Removal in Python 3 15<5>-Footnote-217118956
Ref: Pending Removal in Python 3 15<5>-Footnote-317119011
Ref: Pending Removal in Python 3 15<5>-Footnote-417119066
Ref: Pending Removal in Python 3 15<5>-Footnote-517119122
Ref: Pending Removal in Python 3 15<5>-Footnote-617119164
Node: Pending removal in Python 3 16<5>17119220
Ref: deprecations/index pending-removal-in-python-3-1617119386
Ref: 55fc17119386
Ref: Pending removal in Python 3 16<5>-Footnote-117121565
Node: Pending removal in Python 3 17<3>17121621
Ref: deprecations/index pending-removal-in-python-3-1717121787
Ref: 55fd17121787
Ref: Pending removal in Python 3 17<3>-Footnote-117124715
Ref: Pending removal in Python 3 17<3>-Footnote-217124773
Ref: Pending removal in Python 3 17<3>-Footnote-317124828
Ref: Pending removal in Python 3 17<3>-Footnote-417124886
Node: Pending removal in Python 3 18<2>17124941
Ref: deprecations/index pending-removal-in-python-3-1817125111
Ref: 55fe17125111
Ref: Pending removal in Python 3 18<2>-Footnote-117125533
Node: Pending Removal in Future Versions<5>17125588
Ref: deprecations/index pending-removal-in-future-versions17125743
Ref: 55ff17125743
Ref: Pending Removal in Future Versions<5>-Footnote-117132531
Ref: Pending Removal in Future Versions<5>-Footnote-217132586
Ref: Pending Removal in Future Versions<5>-Footnote-317132642
Ref: Pending Removal in Future Versions<5>-Footnote-417132698
Ref: Pending Removal in Future Versions<5>-Footnote-517132753
Node: C API Deprecations17132808
Ref: deprecations/index c-api-deprecations17132921
Ref: 560017132921
Node: Pending Removal in Python 3 14<6>17133195
Ref: deprecations/index id117133325
Ref: 560117133325
Ref: Pending Removal in Python 3 14<6>-Footnote-117136548
Ref: Pending Removal in Python 3 14<6>-Footnote-217136590
Ref: Pending Removal in Python 3 14<6>-Footnote-317136646
Node: Pending Removal in Python 3 15<6>17136701
Ref: deprecations/index id217136877
Ref: 560217136877
Node: Pending Removal in Future Versions<6>17138126
Ref: deprecations/index id317138260
Ref: 560317138260
Node: Glossary17140497
Ref: glossary doc17140599
Ref: 560417140599
Ref: glossary glossary17140599
Ref: 1d7017140599
Ref: glossary id117140599
Ref: 560517140599
Ref: glossary translation-repo17140599
Ref: 560617140599
Ref: glossary term-017140624
Ref: 16c17140624
Ref: glossary term-17140798
Ref: 16d17140798
Ref: glossary term-abstract-base-class17141216
Ref: 11fa17141216
Ref: glossary term-annotation17142048
Ref: 45b17142048
Ref: glossary term-argument17142726
Ref: 44c17142726
Ref: glossary term-asynchronous-context-manager17144160
Ref: 5da17144160
Ref: glossary term-asynchronous-generator17144394
Ref: 21f217144394
Ref: glossary term-asynchronous-generator-iterator17145119
Ref: 361f17145119
Ref: glossary term-asynchronous-iterable17145861
Ref: da217145861
Ref: glossary term-asynchronous-iterator17146084
Ref: 1ab17146084
Ref: glossary term-atomic-operation17146494
Ref: 560817146494
Ref: glossary term-attribute17146976
Ref: 265817146976
Ref: glossary term-awaitable17147541
Ref: 1ad17147541
Ref: glossary term-BDFL17147738
Ref: 560b17147738
Ref: glossary term-binary-file17147835
Ref: 1e2617147835
Ref: glossary term-borrowed-reference17148292
Ref: 33f17148292
Ref: glossary term-bytes-like-object17148989
Ref: d5517148989
Ref: glossary term-bytecode17149951
Ref: 18717149951
Ref: glossary term-callable17150680
Ref: 2acb17150680
Ref: glossary term-callback17151074
Ref: 2aee17151074
Ref: glossary term-class17151192
Ref: 1aa417151192
Ref: glossary term-class-variable17151357
Ref: 560c17151357
Ref: glossary term-closure-variable17151503
Ref: 20f417151503
Ref: glossary term-complex-number17152598
Ref: 560d17152598
Ref: glossary term-concurrency17153368
Ref: 560e17153368
Ref: glossary term-concurrent-modification17153942
Ref: 561017153942
Ref: glossary term-context17154215
Ref: 16b417154215
Ref: glossary term-context-management-protocol17154807
Ref: 16b617154807
Ref: glossary term-context-manager17154970
Ref: 5d717154970
Ref: glossary term-context-variable17155160
Ref: 561117155160
Ref: glossary term-contiguous17155452
Ref: 23dc17155452
Ref: glossary term-coroutine17155995
Ref: 49417155995
Ref: glossary term-coroutine-function17156318
Ref: da117156318
Ref: glossary term-CPython17156632
Ref: 6f917156632
Ref: glossary term-current-context17156885
Ref: 16b517156885
Ref: glossary term-data-race17157358
Ref: 560a17157358
Ref: glossary term-deadlock17157992
Ref: 561717157992
Ref: glossary term-decorator17158650
Ref: 73417158650
Ref: glossary term-descriptor17159364
Ref: 167717159364
Ref: glossary term-dictionary17160212
Ref: 213b17160212
Ref: glossary term-dictionary-comprehension17160418
Ref: 561917160418
Ref: glossary term-dictionary-view17160763
Ref: 26dc17160763
Ref: glossary term-docstring17161209
Ref: 22e017161209
Ref: glossary term-duck-typing17161606
Ref: 560717161606
Ref: glossary term-dunder17162311
Ref: 561a17162311
Ref: glossary term-EAFP17162509
Ref: 2d7717162509
Ref: glossary term-expression17162955
Ref: 213517162955
Ref: glossary term-extension-module17163469
Ref: 480c17163469
Ref: glossary term-f-string17163597
Ref: 43917163597
Ref: glossary term-file-object17163792
Ref: 120817163792
Ref: glossary term-file-like-object17164555
Ref: 15f417164555
Ref: glossary term-filesystem-encoding-and-error-handler17164618
Ref: 53e17164618
Ref: glossary term-finder17165489
Ref: 20cd17165489
Ref: glossary term-floor-division17165887
Ref: 94e17165887
Ref: glossary term-free-threading17166263
Ref: 15b317166263
Ref: glossary term-free-variable17166558
Ref: 218c17166558
Ref: glossary term-function17166975
Ref: 220d17166975
Ref: glossary term-function-annotation17167282
Ref: 1dcf17167282
Ref: glossary term-__future__17167970
Ref: ddb17167970
Ref: glossary term-garbage-collection17168603
Ref: 1a8317168603
Ref: glossary term-generator17168923
Ref: 109f17168923
Ref: glossary term-generator-iterator17169439
Ref: bff17169439
Ref: glossary term-generator-expression17169829
Ref: 561c17169829
Ref: glossary term-generic-function17170234
Ref: 9fc17170234
Ref: glossary term-generic-type17170593
Ref: 43c17170593
Ref: glossary term-GIL17170956
Ref: 15917170956
Ref: glossary term-global-interpreter-lock17171007
Ref: 14817171007
Ref: glossary term-global-state17172258
Ref: 561d17172258
Ref: glossary term-hash-based-pyc17172615
Ref: 561e17172615
Ref: glossary term-hashable17172829
Ref: 61317172829
Ref: glossary term-IDLE17173745
Ref: 561f17173745
Ref: glossary term-immortal17173981
Ref: 45dd17173981
Ref: glossary term-immutable17174332
Ref: 1d9117174332
Ref: glossary term-import-path17174893
Ref: 21a917174893
Ref: glossary term-importing17175232
Ref: 219c17175232
Ref: glossary term-importer17175353
Ref: 21a817175353
Ref: glossary term-interactive17175479
Ref: 16917175479
Ref: glossary term-interpreted17175970
Ref: 562017175970
Ref: glossary term-interpreter-shutdown17176462
Ref: 14e17176462
Ref: glossary term-iterable17177197
Ref: 126d17177197
Ref: glossary term-iterator17178383
Ref: 1ac17178383
Ref: glossary term-key-function17179900
Ref: e3717179900
Ref: glossary term-keyword-argument17181065
Ref: d3a17181065
Ref: glossary term-lambda17181114
Ref: 290817181114
Ref: glossary term-LBYL17181347
Ref: 561b17181347
Ref: glossary term-lexical-analyzer17182093
Ref: 562117182093
Ref: glossary term-list17182173
Ref: 562217182173
Ref: glossary term-list-comprehension17182357
Ref: 6d117182357
Ref: glossary term-lock17182775
Ref: 561317182775
Ref: glossary term-lock-free17183585
Ref: 562317183585
Ref: glossary term-loader17184173
Ref: 17c117184173
Ref: glossary term-locale-encoding17184533
Ref: 24217184533
Ref: glossary term-magic-method17184993
Ref: 433a17184993
Ref: glossary term-mapping17185065
Ref: 120017185065
Ref: glossary term-meta-path-finder17185471
Ref: 10ae17185471
Ref: glossary term-metaclass17185769
Ref: 213617185769
Ref: glossary term-method17186509
Ref: 165717186509
Ref: glossary term-method-resolution-order17186818
Ref: 233917186818
Ref: glossary term-module17187104
Ref: 177217187104
Ref: glossary term-module-spec17187367
Ref: 20c517187367
Ref: glossary term-MRO17187574
Ref: 15e617187574
Ref: glossary term-mutable17187626
Ref: 1d9617187626
Ref: glossary term-named-tuple17188006
Ref: 65117188006
Ref: glossary term-namespace17189226
Ref: 1df517189226
Ref: glossary term-namespace-package17189982
Ref: 1e0617189982
Ref: glossary term-native-code17190562
Ref: 561517190562
Ref: glossary term-nested-scope17190934
Ref: 20f317190934
Ref: glossary term-new-style-class17191423
Ref: 2a5e17191423
Ref: glossary term-non-deterministic17191750
Ref: 561217191750
Ref: glossary term-object17192208
Ref: 562517192208
Ref: glossary term-optimized-scope17192372
Ref: 17e17192372
Ref: glossary term-package17192903
Ref: 20c917192903
Ref: glossary term-parallelism17193175
Ref: 560f17193175
Ref: glossary term-parameter17193699
Ref: 20ae17193699
Ref: glossary positional-only-parameter17194228
Ref: a9417194228
Ref: glossary keyword-only-parameter17194628
Ref: 2a517194628
Ref: glossary term-per-object-lock17196139
Ref: 562417196139
Ref: glossary term-path-entry17196698
Ref: 21b717196698
Ref: glossary term-path-entry-finder17196852
Ref: 10af17196852
Ref: glossary term-path-entry-hook17197176
Ref: 21b917197176
Ref: glossary term-path-based-finder17197377
Ref: 21ac17197377
Ref: glossary term-path-like-object17197513
Ref: 2a017197513
Ref: glossary term-PEP17198111
Ref: 562617198111
Ref: glossary term-portion17198765
Ref: 21a317198765
Ref: glossary term-positional-argument17198926
Ref: d3b17198926
Ref: glossary term-provisional-API17198978
Ref: b1c17198978
Ref: glossary term-provisional-package17199982
Ref: 107f17199982
Ref: glossary term-Python-300017200041
Ref: 562717200041
Ref: glossary term-Pythonic17200234
Ref: 562817200234
Ref: glossary term-qualified-name17200874
Ref: 1acb17200874
Ref: glossary term-race-condition17201719
Ref: 560917201719
Ref: glossary term-reference-count17202357
Ref: 4b9417202357
Ref: glossary term-regular-package17203155
Ref: 21a017203155
Ref: glossary term-reentrant17203322
Ref: 561817203322
Ref: glossary term-REPL17204255
Ref: 16a17204255
Ref: glossary term-__slots__17204387
Ref: 5e217204387
Ref: glossary term-sequence17204733
Ref: 4f417204733
Ref: glossary term-set-comprehension17205854
Ref: 562917205854
Ref: glossary term-single-dispatch17206170
Ref: 9fd17206170
Ref: glossary term-slice17206321
Ref: 233617206321
Ref: glossary term-soft-deprecated17206646
Ref: 20917206646
Ref: glossary term-special-method17207018
Ref: 1a0617207018
Ref: glossary term-standard-library17207298
Ref: 562a17207298
Ref: glossary term-statement17207809
Ref: 295117207809
Ref: glossary term-static-type-checker17208053
Ref: 26d17208053
Ref: glossary term-stdlib17208260
Ref: 15d217208260
Ref: glossary term-strong-reference17208323
Ref: 33e17208323
Ref: glossary term-synchronization-primitive17208981
Ref: 561417208981
Ref: glossary term-text-encoding17209697
Ref: 233317209697
Ref: glossary term-text-file17210221
Ref: 1e2517210221
Ref: glossary term-thread-safe17210744
Ref: 561617210744
Ref: glossary term-token17211459
Ref: 202917211459
Ref: glossary term-triple-quoted-string17211839
Ref: 562b17211839
Ref: glossary term-type17212339
Ref: 1aa517212339
Ref: glossary term-type-alias17212573
Ref: 43d17212573
Ref: glossary term-type-hint17213154
Ref: 213117213154
Ref: glossary term-universal-newlines17213755
Ref: d6217213755
Ref: glossary term-variable-annotation17214129
Ref: d7f17214129
Ref: glossary term-virtual-environment17214856
Ref: 1ea517214856
Ref: glossary term-virtual-machine17215165
Ref: 372b17215165
Ref: glossary term-walrus-operator17215331
Ref: 562c17215331
Ref: glossary term-Zen-of-Python17215512
Ref: 562d17215512
Ref: Glossary-Footnote-117215779
Ref: Glossary-Footnote-217215821
Ref: Glossary-Footnote-317215863
Ref: Glossary-Footnote-417215905
Ref: Glossary-Footnote-517215947
Ref: Glossary-Footnote-617215989
Ref: Glossary-Footnote-717216031
Ref: Glossary-Footnote-817216073
Ref: Glossary-Footnote-917216115
Ref: Glossary-Footnote-1017216157
Ref: Glossary-Footnote-1117216196
Ref: Glossary-Footnote-1217216239
Ref: Glossary-Footnote-1317216282
Ref: Glossary-Footnote-1417216325
Ref: Glossary-Footnote-1517216368
Ref: Glossary-Footnote-1617216400
Ref: Glossary-Footnote-1717216443
Ref: Glossary-Footnote-1817216486
Ref: Glossary-Footnote-1917216529
Ref: Glossary-Footnote-2017216572
Ref: Glossary-Footnote-2117216615
Ref: Glossary-Footnote-2217216658
Ref: Glossary-Footnote-2317216701
Ref: Glossary-Footnote-2417216744
Ref: Glossary-Footnote-2517216787
Ref: Glossary-Footnote-2617216830
Ref: Glossary-Footnote-2717216873
Ref: Glossary-Footnote-2817216916
Ref: Glossary-Footnote-2917216959
Ref: Glossary-Footnote-3017217002
Ref: Glossary-Footnote-3117217045
Ref: Glossary-Footnote-3217217088
Ref: Glossary-Footnote-3317217131
Ref: Glossary-Footnote-3417217174
Ref: Glossary-Footnote-3517217234
Ref: Glossary-Footnote-3617217277
Ref: Glossary-Footnote-3717217320
Ref: Glossary-Footnote-3817217363
Ref: Glossary-Footnote-3917217406
Ref: Glossary-Footnote-4017217449
Node: About this documentation17217492
Ref: about doc17217599
Ref: 562e17217599
Ref: about about-this-documentation17217599
Ref: 562f17217599
Ref: about translation-repo17217599
Ref: 563017217599
Ref: About this documentation-Footnote-117218548
Ref: About this documentation-Footnote-217218597
Ref: About this documentation-Footnote-317218633
Node: Contributors to the Python documentation17218674
Ref: about contributors-to-the-python-documentation17218775
Ref: 563117218775
Ref: Contributors to the Python documentation-Footnote-117219234
Node: Dealing with Bugs17219296
Ref: bugs doc17219404
Ref: 563217219404
Ref: bugs dealing-with-bugs17219404
Ref: 563317219404
Ref: bugs reporting-bugs17219404
Ref: 4be417219404
Ref: bugs translation-repo17219404
Ref: 563417219404
Node: Documentation bugs17219947
Ref: bugs documentation-bugs17220058
Ref: 563617220058
Ref: Documentation bugs-Footnote-117221082
Ref: Documentation bugs-Footnote-217221136
Ref: Documentation bugs-Footnote-317221188
Ref: Documentation bugs-Footnote-417221274
Ref: Documentation bugs-Footnote-517221319
Ref: Documentation bugs-Footnote-617221395
Node: Using the Python issue tracker17221458
Ref: bugs using-the-python-issue-tracker17221625
Ref: 563717221625
Ref: bugs using-the-tracker17221625
Ref: 24e17221625
Ref: Using the Python issue tracker-Footnote-117223857
Ref: Using the Python issue tracker-Footnote-217223920
Node: Getting started contributing to Python yourself17223986
Ref: bugs contributing-to-python17224126
Ref: 563517224126
Ref: bugs getting-started-contributing-to-python-yourself17224126
Ref: 563817224126
Ref: Getting started contributing to Python yourself-Footnote-117224643
Ref: Getting started contributing to Python yourself-Footnote-217224680
Node: Copyright17224756
Ref: copyright doc17224859
Ref: 563917224859
Ref: copyright copyright17224859
Ref: 563a17224859
Ref: copyright translation-repo17224859
Ref: 563b17224859
Node: History and License17225374
Ref: license doc17225479
Ref: 563d17225479
Ref: license history-and-license17225479
Ref: 563c17225479
Ref: license id117225479
Ref: 563e17225479
Ref: license translation-repo17225479
Ref: 563f17225479
Node: History of the software17225689
Ref: license history-of-the-software17225837
Ref: 564017225837
Node: Terms and conditions for accessing or otherwise using Python17230671
Ref: license terms-and-conditions-for-accessing-or-otherwise-using-python17230883
Ref: 564117230883
Node: PYTHON SOFTWARE FOUNDATION LICENSE VERSION 217231953
Ref: license psf-license17232146
Ref: 564417232146
Ref: license python-software-foundation-license-version-217232146
Ref: 564517232146
Node: BEOPEN COM LICENSE AGREEMENT FOR PYTHON 2 017234768
Ref: license beopen-com-license-agreement-for-python-2-017235009
Ref: 564617235009
Node: CNRI LICENSE AGREEMENT FOR PYTHON 1 6 117237717
Ref: license cnri-license-agreement-for-python-1-6-117237964
Ref: 564717237964
Node: CWI LICENSE AGREEMENT FOR PYTHON 0 9 0 THROUGH 1 217242142
Ref: license cwi-license-agreement-for-python-0-9-0-through-1-217242406
Ref: 564817242406
Node: ZERO-CLAUSE BSD LICENSE FOR CODE IN THE PYTHON DOCUMENTATION17243676
Ref: license bsd017243892
Ref: 564217243892
Ref: license zero-clause-bsd-license-for-code-in-the-python-documentation17243892
Ref: 564917243892
Node: Licenses and Acknowledgements for Incorporated Software17244682
Ref: license licenses-and-acknowledgements-for-incorporated-software17244862
Ref: 564a17244862
Ref: license otherlicenses17244862
Ref: 564317244862
Node: Mersenne Twister17245613
Ref: license mersenne-twister17245740
Ref: 564b17245740
Node: Sockets<2>17248059
Ref: license sockets17248223
Ref: 564c17248223
Node: Asynchronous socket services17250056
Ref: license asynchronous-socket-services17250221
Ref: 564d17250221
Node: Cookie management17251459
Ref: license cookie-management17251631
Ref: 564e17251631
Node: Execution tracing17252848
Ref: license execution-tracing17253023
Ref: 564f17253023
Node: UUencode and UUdecode functions17254282
Ref: license uuencode-and-uudecode-functions17254466
Ref: 565017254466
Node: XML Remote Procedure Calls17256041
Ref: license xml-remote-procedure-calls17256218
Ref: 565117256218
Node: test_epoll17257743
Ref: license test-epoll17257902
Ref: 565217257902
Node: Select kqueue17259167
Ref: license select-kqueue17259309
Ref: 565317259309
Node: SipHash2417260861
Ref: license siphash2417261008
Ref: 565417261008
Node: strtod and dtoa17262191
Ref: license strtod-and-dtoa17262335
Ref: 565517262335
Node: OpenSSL<2>17263732
Ref: license openssl17263872
Ref: 565617263872
Node: expat17274790
Ref: license expat17274921
Ref: 565717274921
Node: libffi17276327
Ref: license libffi17276455
Ref: 565817276455
Node: zlib<3>17277836
Ref: license zlib17277966
Ref: 565917277966
Node: cfuhash17279199
Ref: license cfuhash17279331
Ref: 565a17279331
Node: libmpdec17281147
Ref: license libmpdec17281291
Ref: 565b17281291
Node: W3C C14N test suite17282901
Ref: license w3c-c14n-test-suite17283046
Ref: 565c17283046
Node: mimalloc17284948
Ref: license mimalloc17285096
Ref: 565d17285096
Ref: license mimalloc-license17285096
Ref: 41417285096
Node: asyncio<12>17286309
Ref: license asyncio17286468
Ref: 565e17286468
Ref: asyncio<12>-Footnote-117287825
Node: Global Unbounded Sequences GUS17287883
Ref: license global-unbounded-sequences-gus17288025
Ref: 565f17288025
Ref: Global Unbounded Sequences GUS-Footnote-117289707
Node: Python Module Index17289785
Node: Index17309016
Ref: 442619418549
Ref: library/asyncio audit_event_cpython_run_stdin_019418550
Ref: 442419418552
Ref: library/stdtypes tuple index19418554
Ref: using/cmdline audit_event_cpython_run_file_019418556
Ref: library/stdtypes tuple count19418558
Ref: library/stdtypes list extend19418560
Ref: 140f19418562
Ref: 442519418564
Ref: library/stdtypes list pop19418566
Ref: 36019418568
Ref: library/unittest unittest tearDownModule19418570
Ref: library/stdtypes list insert19418572
Ref: library/time audit_event_time_sleep_019418574
Ref: 1ddb19418576
Ref: library/stdtypes list clear19418578
Ref: 36119418580
Ref: 17fa19418582
Ref: 141019418584
Ref: 11dc19418586
Ref: library/_thread start_new_thread19418588
Ref: library/stdtypes list remove19418590
Ref: using/cmdline audit_event_cpython_run_stdin_119418592
Ref: 442319418594
Ref: 138119418596
Ref: 442e19418598
Ref: 442019418600
Ref: 6d019418602
Ref: using/cmdline audit_event_cpython_run_stdin_019418604
Ref: library/stdtypes list append19418606

End Tag Table


Local Variables:
coding: utf-8
End:
